CA1143398A - Seal for a cylinder-piston arrangement - Google Patents
Seal for a cylinder-piston arrangementInfo
- Publication number
- CA1143398A CA1143398A CA000350144A CA350144A CA1143398A CA 1143398 A CA1143398 A CA 1143398A CA 000350144 A CA000350144 A CA 000350144A CA 350144 A CA350144 A CA 350144A CA 1143398 A CA1143398 A CA 1143398A
- Authority
- CA
- Canada
- Prior art keywords
- working
- tube
- tube member
- cylinder
- supporting wall
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J3/00—Diaphragms; Bellows; Bellows pistons
- F16J3/06—Bellows pistons
Abstract
ABSTRACT
In the case of cylinder-piston arrangements having a sealing tube (10), which is connected on one side to the piston (4) and on the other side to the cylinder (6) and under high working pressure rests against a bearing surface (6a), in the region of that connection of the tube (12) which exhibits the greatest relative speed with respect to the bearing surface (6a) critical loadings of the tube arise with increased radial pressure and if the occasion arises outwards deformation with direct sliding contact between the surface of the tube and the bearing surface.
This problem is solved by at least one intermediate part (20) arranged in the critical connection region (12) and.
embracing the sealing tube (10) and/or the working member in question,e.g., the piston (4), and consisting preferably of slide-promoting material and able to exert also a radial restraining action upon the material of the tube in the connection region as well as a heat-insulating action with respect to adjoining heat sources, e.g., driving parts.
(Figure 2)
In the case of cylinder-piston arrangements having a sealing tube (10), which is connected on one side to the piston (4) and on the other side to the cylinder (6) and under high working pressure rests against a bearing surface (6a), in the region of that connection of the tube (12) which exhibits the greatest relative speed with respect to the bearing surface (6a) critical loadings of the tube arise with increased radial pressure and if the occasion arises outwards deformation with direct sliding contact between the surface of the tube and the bearing surface.
This problem is solved by at least one intermediate part (20) arranged in the critical connection region (12) and.
embracing the sealing tube (10) and/or the working member in question,e.g., the piston (4), and consisting preferably of slide-promoting material and able to exert also a radial restraining action upon the material of the tube in the connection region as well as a heat-insulating action with respect to adjoining heat sources, e.g., driving parts.
(Figure 2)
Description
~4;~
Seal for a cylinder-piston arran~ement The invention relates to an apparatus comprising a cylinder-piston arrangement having two working members movable relatively to one another and having a sealing tube which bounds a working space and is positively connected to at least one of the two working members, and under the pressure in the working space, preferably via a lubricant, bears against a bearing surface formed by the other working member.
Cylinder-piston arrangements of the aforesaid kind find employment particularly as pumps and motors for working liquids which are under high pressure. The sealing tube connected to the two working members, i.e., piston and cylinder, takes part by elastic compression or stretching respectively in its longitudinal direction in the periodic - alteration in the working space and brings about a hermetic sealing which at high pressures can be achieved in other ways only with difficulty. In the case of the conveyance of corrosive or poisonous liquids the hermetic sealing which can hereby be achieved is of significance too.
A considerable problem in the case of cylinder-piston arrangements of the present kind at high working pressures is the sliding motion occurring under correspondingly high r~ , \
~"~ ,r - ~43;~98 - la -contact pressure between the outer face of the sealing tube and the bearing surface. In particular in the connection region of the sealing tube to the working member which moves with respect to the bearing surface a high loading of the ' ', ' ' ' , ' . ,:
~4~3g8 material of the tube results, because the sliding speed of the surface of the tube here corresponds with the full value of the relative speed of the working member in question with respect to the bearing surface (in the direction towards the opposite point of connection onto the working member forming the bearing surface this sliding speed diminishes with the degree of deformation of the tube down to zero). Even in the case of introduction of a lubricant liquid into the clearance volume between the sealing tube and the bearing surface with discharge from this clearance volume in the connection region between the tube and the first working member critical deformation and sliding conditions result here because the flexible material of the sealing tube under the action of the working pressure is still being pressed strongly against the bearing surface, whilst on the other hand the lubricant pressure close to the discharge opening from the clearance volume already drops off. Under certain circums~ances therefore in the transition region direct contact between the material of the seal and the bearing surface with corresponding mixe ~ riction and wear of the surface of the tube may result, above all in combination with the heating of the material of the seal caused : by high-pressure friction. On the other hand the outwards deformation of the material of the seal in the region of the discharge out of the clearance volume cannot be suppressed at : option because here if necessary a throttling action with respect to the escaping lubricant liquid is striven for by narrowing of the clearance volume, Such a throttle, self- '.
adjusting under the action of deformation from working pressure, offers the advantage of a reliable maintenance of pressure and maintenance o~ the distance between the surface of the . ~ ... , . , , ~ , ', ~i43398 ~ _ 3 _ tube and the bearing surface in the main region of the surface of the tube lying at the back of it. But the outwards deformation of the material of the tube leads again to the danger of contact with the bearing surface with the injurious consequences of it which have been mentioned.
It is an object of the present invention to provide an improved sealing arrangement having low susceptibility to wear and damage to the sealing tube in the region of maximum sliding speed with respect to the bearing surface.
According to the invention there is provided an apparatus comprising two working members formed as a piston and a cylinder and being relatively movable, an elastic tube member sealingly engaging said working members at spaced locations and at least partially defining a working chamber, said tube member stretching and contracting and said working chamber varying in volume as said working members move relatively, said tube member having a surface portion sliding against a cylindrical supporting wall of a first one of said working members as the volume of said working chamber varies, and a ring member extending along the circumference of said tube member and located between said tube member and said supporting wall of said first working member in the region .
~3398 - 3a -of connection of said tube member with the second one of said working members for limiting radial deformation of said tube member in direction towards said supporting wall of said first working member, said ring member being elastically deformable and having a radial prestress against said tube member.
The arrangement of an intermediate part embracing the sealing tube in its connection region offers first of all the possibility of screening this exposed section of the material of the tube against contact with the bearing surface and hence against damage. For this purpose an exècution of the intermediate part from slide-promoting material particularly comes into consideration, espscially a slide-promoting plastics, preferably from polytetra-fluroethylene or a similar polymer plastics. Independentlyof that, but if necessary even in addition, such an intermediate part may exert a restraining action directed radially inwards on the material of the tube in the connection region and thereby against the radially out-: 20 wards directed components of the working pressure prevent the bulging of the materlal of the tube and possible contact of it with the bearing surface. In order to do that thepreferably annular intermediate part is advantageously mounted with compressive prestress directed radially inwards on the connection region of the sealing tube. If in spite of that, sliding contact occurs against the bearing sur~ace, the intermediate part again takes over its protective function with respect to the material of the tube. As a further function such an intermediate part may with deliberately permitted radial expansion under the action of the working pressure acting on the inside of it, take over the formation of a self-adjusting throttle for a lubricant escaping from the clearance volume between the tube and the bearing surface. In order to do this the section of the intermediate part next to the working space is advantageously made comparatively thinwalled in the form of a sleeve or a collar tapering off to a point, which is expanded radially at its edge region next to the working space and forms here an annular throttling gap. The transfer of the working pressure to the inner face of the intermediate part may be brought about ~y the elastic material of the connection region of the sealLng tube, which wholly or partially fills the interior of the intermediate part. As has been said, in practice by appropriate shaping and dimensioning of the intermediate part, in particularits annular or wall-like part which extends along the circumference of the bearing surface, com~binations of the various functions mentioned may deliberately be adjusted.
Further features and advantages of the invention are explained with the aid of the embodimentsillustrated diagrammatically in the drawings. In these there is shown in:
.
. :
~5~ i~4~8 Figure 1 - an axial section through a cylinder-piston arrangement ~aving a sealing tube as an example insertion of application for the // of an annular intermediate part;
Figure 2 - on a larger scale a partial axial section of the connection region of the sealing tube onto a working member made as a piston, with an annular intermediate part inserted;
Figure 2 a - a modified cross-sectional shape of an annular intermediate part with an auxiliary spring;
: Fig~lre 2 b - a further execution of the cross-section of an annular intermediate part, likewise with an auxiliary spring ring; and Figure 3 - a partial axial section similar to Figure 2 with a can-shaped intermediate part in the connection region of the sealing tube.
In accordance with Figure 1 the cylinder-piston arrangement 1 acting, for example, as pump, is driven by an eccentric 2 ~: a : via/non-rotating bearing ring 3 in the direction of the arrow P. A first working member 4,here made as a piston,bears downwards by a guide and ram section 4a against the bearing ~` ~ . ring 3 and hence executes an oscillating working motion in accordance with the arrow P. A second working member 6 made as a cylinder encloses a working space 8 inside which is accommodated a spiral compression spring 9 holding the piston i working member 4 in contact against the bearing ring 3. Inside tbe cylinder working member 6 a sea-ing tube 10 is arranged, ~ 1~4339~
which by its outer face bears radially against the cylindrical bearing surface 6a of the working member 6 under the action of the pressure in the working space 8. The bottom end of the sealing tube 10 by a connection region 12 has a connection of the substance of the material, preferably by vulcanization, to the pistor working member 4 and hence is subjected to an aYial stretchingand compression in accordance with the working motion corresponding with the arrow P. At the top end the sealing tube 10 is connec~ed solidly by a connection region 13 with a clamp connection or a connection of the substance of the material to the head section 6b of the cylinder working member 6. Hence the working space 8 is hermetically sealedall round by the sealing tube 10 which takes part by its axial deformation in the periodic alteration of the working space. In a way not shown in greater detail a lubricant liquid is forced via a connection 14 into the clearance volume between the outer face of the sealing tube 10 and the bearing surface 6a and flows down through this clearance volume in the axial direction and at the bottom end of the connection region 12 of the sealing tube flows away via a throttle point into a low pressure chamber, for example, an annular space 16 provided with outlet channels (not shown).
Because of this throttling of the discharge a lubricant pressure may be developed in the clearance volume between the sealing tube and the bearing surface, which is in e~uilibrium with the pressure in the working space, to exclude contact and mixed friction between the tube ana the bearing surface. In order to do that an appropriate dimensioning and adjustment of the elasticity of the throttle point in the connection region 12 is necessary, which is achieved by the insertion of an annular intermediate part 20 which is seated, for . .
. . .; . . . :
~ '. ' ..
-7- ~43~8 example, with radial prestress on the material of the tube.
The construction and arrangement of the annular intermediate part 20 may be seen in detail ~rom Figure 2. According to that the cross-section of this intermediate part is made triangular with the outside arranged in parallel with the direction of the generatrix of the bearing surface 6a and the end section tapering out into a sharp edge in the direction of the working space 8. On the opposite side the intermediate part exhibits a side of the cross-section running radially, which bears against an axial stop 4b on the piston working member 4 against the axial component of the pressure prevailing in the working space 8. This pressure is transmitted by the elastic material of the connection region 12 of the sealing tube to the inside of the intermediate part 20. A radially expanding component of the pressure acting upon this annular body thereby also results, which in the case of appropriately elastic deform-ability may be made use of for direct participation of the outer face of the intermediate part and in particular of the edge section 22 of it ne~t to the working space, in the formation of a self-adjusting discharge throttle for the lubricant flowing along the bearing surface 6a from left to right in the sense of Figure 2. On the contrary a comparatively great stiffness against stretching of the ~annular body leads to an excessive constricti~e function or restraining function in respect of the elastic material of the connection region 12, so that the throttling action can be adjusted by radial bulging of the material of the seal independently of the more or less complicated shape of the .
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profile of the axial section and of the area of vulcanization on the piston working member.
The radial prestress effect and the stiffness against stretching of the intermediate part can be adapted to the requirement at the time with the aid of auxiliary springs. Figure 2a sho-~s a comparatively weakly acting annular spiral tension spring 26 in the axial section through an annular intermediate part 20a having a trapezoidal profile. The auxiliary spring 26 is accommodated here in an outer circumferential groove in the annular body. Figure 2b shows a modified execution of the profile of an annular intermediate part 20b having lower radial extensibility because of a more massive shape of cross-section, furthermore because of a massive spring ring accommodated in a corresponding circumferential groove. Such an execution can scarcely be called upon for the formation of a throttle under radial expansion but brings about a stiff constriction and restraint of the connection region of the sealing tube against bulging under the working pressure.
The radially expandable executions as Figure 2 and Figure 2a offer on the contrary the further particular advantage that the annular body can during assembly be forced axially onto the piston which can be produced in one piece, past the greatest diameter of the axial stop 4b. On the other hand fitting is also possible o~ the smaller-diameter section of plston on the side next the working space, in the state before the vulcanization onto the connection region of the sealing tube. The centreing and embedding into the mass of the seal is then effected by the vulcanization.
In this case a connection of the substance of the material ,; . . ~ ' ~ ' ' ' ' ' : - ' :- ' 9 ~,43398 ," . .
does not readily result with the pla~tics ofthe intermediate part, but only to the surface of the piston working member.
A sufficient radial prestress leads nevertheless to sealing against the luhricant liquid from the clearance volume between the sealing tube and the bearing surface. On the other hand a certain admission under the annular body of the intermediate part, of the lubricant liquid under pressure, for assisting the radial expansion during throttle formation may be desirable.
In the case o~ the execution as in Figure 3 the intermediate part 30 is can-shaped and provided with a thinwalled and therefore easily stretchable wall part 32 extending along the bearing surface 6a, as well as with a thickwalled and stiff bottom or flange part 34. The latter is fastened by means of a thrust washer and a bolted joint (not shown) to the piston working member 4 and imparts radial stiffness to the outer end section of the wall part. The edge section 32a of the wall part 32 next the working space on the contrary expands comparatively widely radially under the action of the working pressure in the space 8 or respectively the corresponding pressure in the flexible material of the connection region 12 of the sealing tube and thus may form mainly or exclusively a self-adjusting throttle. If necessary for this purpose a shape of the wall part 32 may advantageously be provided which is already in the unstressed state slightly conical, diverging towards the working space.
For the rest the interior of the can-shaped intermediate part may if necessary be kept wholly or partially free of the material of the sealing tube if exp~nsion for the formation : ~
, ~ ~ - 1 o- 1~43398 of a throttle is effective in some other way. Under certain circumstances, for doing this the pressure of the lubricant entering from the clearance volume comes into consideration, which depends upon the pressure in the working space or respectively is in equilibrium with it.
Furthermore the heat-insulating action of the intermediate part is particularly advantageous, especially also the execution as in Figure 3 with its wide wall part, against a flow of heat from the cylinder or respectively - as regards the bottom part ~ from the driving cam with its heat of friction. This screening against additional heating contributes considerably to the resistance of the material of the tube in the connection region.
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Seal for a cylinder-piston arran~ement The invention relates to an apparatus comprising a cylinder-piston arrangement having two working members movable relatively to one another and having a sealing tube which bounds a working space and is positively connected to at least one of the two working members, and under the pressure in the working space, preferably via a lubricant, bears against a bearing surface formed by the other working member.
Cylinder-piston arrangements of the aforesaid kind find employment particularly as pumps and motors for working liquids which are under high pressure. The sealing tube connected to the two working members, i.e., piston and cylinder, takes part by elastic compression or stretching respectively in its longitudinal direction in the periodic - alteration in the working space and brings about a hermetic sealing which at high pressures can be achieved in other ways only with difficulty. In the case of the conveyance of corrosive or poisonous liquids the hermetic sealing which can hereby be achieved is of significance too.
A considerable problem in the case of cylinder-piston arrangements of the present kind at high working pressures is the sliding motion occurring under correspondingly high r~ , \
~"~ ,r - ~43;~98 - la -contact pressure between the outer face of the sealing tube and the bearing surface. In particular in the connection region of the sealing tube to the working member which moves with respect to the bearing surface a high loading of the ' ', ' ' ' , ' . ,:
~4~3g8 material of the tube results, because the sliding speed of the surface of the tube here corresponds with the full value of the relative speed of the working member in question with respect to the bearing surface (in the direction towards the opposite point of connection onto the working member forming the bearing surface this sliding speed diminishes with the degree of deformation of the tube down to zero). Even in the case of introduction of a lubricant liquid into the clearance volume between the sealing tube and the bearing surface with discharge from this clearance volume in the connection region between the tube and the first working member critical deformation and sliding conditions result here because the flexible material of the sealing tube under the action of the working pressure is still being pressed strongly against the bearing surface, whilst on the other hand the lubricant pressure close to the discharge opening from the clearance volume already drops off. Under certain circums~ances therefore in the transition region direct contact between the material of the seal and the bearing surface with corresponding mixe ~ riction and wear of the surface of the tube may result, above all in combination with the heating of the material of the seal caused : by high-pressure friction. On the other hand the outwards deformation of the material of the seal in the region of the discharge out of the clearance volume cannot be suppressed at : option because here if necessary a throttling action with respect to the escaping lubricant liquid is striven for by narrowing of the clearance volume, Such a throttle, self- '.
adjusting under the action of deformation from working pressure, offers the advantage of a reliable maintenance of pressure and maintenance o~ the distance between the surface of the . ~ ... , . , , ~ , ', ~i43398 ~ _ 3 _ tube and the bearing surface in the main region of the surface of the tube lying at the back of it. But the outwards deformation of the material of the tube leads again to the danger of contact with the bearing surface with the injurious consequences of it which have been mentioned.
It is an object of the present invention to provide an improved sealing arrangement having low susceptibility to wear and damage to the sealing tube in the region of maximum sliding speed with respect to the bearing surface.
According to the invention there is provided an apparatus comprising two working members formed as a piston and a cylinder and being relatively movable, an elastic tube member sealingly engaging said working members at spaced locations and at least partially defining a working chamber, said tube member stretching and contracting and said working chamber varying in volume as said working members move relatively, said tube member having a surface portion sliding against a cylindrical supporting wall of a first one of said working members as the volume of said working chamber varies, and a ring member extending along the circumference of said tube member and located between said tube member and said supporting wall of said first working member in the region .
~3398 - 3a -of connection of said tube member with the second one of said working members for limiting radial deformation of said tube member in direction towards said supporting wall of said first working member, said ring member being elastically deformable and having a radial prestress against said tube member.
The arrangement of an intermediate part embracing the sealing tube in its connection region offers first of all the possibility of screening this exposed section of the material of the tube against contact with the bearing surface and hence against damage. For this purpose an exècution of the intermediate part from slide-promoting material particularly comes into consideration, espscially a slide-promoting plastics, preferably from polytetra-fluroethylene or a similar polymer plastics. Independentlyof that, but if necessary even in addition, such an intermediate part may exert a restraining action directed radially inwards on the material of the tube in the connection region and thereby against the radially out-: 20 wards directed components of the working pressure prevent the bulging of the materlal of the tube and possible contact of it with the bearing surface. In order to do that thepreferably annular intermediate part is advantageously mounted with compressive prestress directed radially inwards on the connection region of the sealing tube. If in spite of that, sliding contact occurs against the bearing sur~ace, the intermediate part again takes over its protective function with respect to the material of the tube. As a further function such an intermediate part may with deliberately permitted radial expansion under the action of the working pressure acting on the inside of it, take over the formation of a self-adjusting throttle for a lubricant escaping from the clearance volume between the tube and the bearing surface. In order to do this the section of the intermediate part next to the working space is advantageously made comparatively thinwalled in the form of a sleeve or a collar tapering off to a point, which is expanded radially at its edge region next to the working space and forms here an annular throttling gap. The transfer of the working pressure to the inner face of the intermediate part may be brought about ~y the elastic material of the connection region of the sealLng tube, which wholly or partially fills the interior of the intermediate part. As has been said, in practice by appropriate shaping and dimensioning of the intermediate part, in particularits annular or wall-like part which extends along the circumference of the bearing surface, com~binations of the various functions mentioned may deliberately be adjusted.
Further features and advantages of the invention are explained with the aid of the embodimentsillustrated diagrammatically in the drawings. In these there is shown in:
.
. :
~5~ i~4~8 Figure 1 - an axial section through a cylinder-piston arrangement ~aving a sealing tube as an example insertion of application for the // of an annular intermediate part;
Figure 2 - on a larger scale a partial axial section of the connection region of the sealing tube onto a working member made as a piston, with an annular intermediate part inserted;
Figure 2 a - a modified cross-sectional shape of an annular intermediate part with an auxiliary spring;
: Fig~lre 2 b - a further execution of the cross-section of an annular intermediate part, likewise with an auxiliary spring ring; and Figure 3 - a partial axial section similar to Figure 2 with a can-shaped intermediate part in the connection region of the sealing tube.
In accordance with Figure 1 the cylinder-piston arrangement 1 acting, for example, as pump, is driven by an eccentric 2 ~: a : via/non-rotating bearing ring 3 in the direction of the arrow P. A first working member 4,here made as a piston,bears downwards by a guide and ram section 4a against the bearing ~` ~ . ring 3 and hence executes an oscillating working motion in accordance with the arrow P. A second working member 6 made as a cylinder encloses a working space 8 inside which is accommodated a spiral compression spring 9 holding the piston i working member 4 in contact against the bearing ring 3. Inside tbe cylinder working member 6 a sea-ing tube 10 is arranged, ~ 1~4339~
which by its outer face bears radially against the cylindrical bearing surface 6a of the working member 6 under the action of the pressure in the working space 8. The bottom end of the sealing tube 10 by a connection region 12 has a connection of the substance of the material, preferably by vulcanization, to the pistor working member 4 and hence is subjected to an aYial stretchingand compression in accordance with the working motion corresponding with the arrow P. At the top end the sealing tube 10 is connec~ed solidly by a connection region 13 with a clamp connection or a connection of the substance of the material to the head section 6b of the cylinder working member 6. Hence the working space 8 is hermetically sealedall round by the sealing tube 10 which takes part by its axial deformation in the periodic alteration of the working space. In a way not shown in greater detail a lubricant liquid is forced via a connection 14 into the clearance volume between the outer face of the sealing tube 10 and the bearing surface 6a and flows down through this clearance volume in the axial direction and at the bottom end of the connection region 12 of the sealing tube flows away via a throttle point into a low pressure chamber, for example, an annular space 16 provided with outlet channels (not shown).
Because of this throttling of the discharge a lubricant pressure may be developed in the clearance volume between the sealing tube and the bearing surface, which is in e~uilibrium with the pressure in the working space, to exclude contact and mixed friction between the tube ana the bearing surface. In order to do that an appropriate dimensioning and adjustment of the elasticity of the throttle point in the connection region 12 is necessary, which is achieved by the insertion of an annular intermediate part 20 which is seated, for . .
. . .; . . . :
~ '. ' ..
-7- ~43~8 example, with radial prestress on the material of the tube.
The construction and arrangement of the annular intermediate part 20 may be seen in detail ~rom Figure 2. According to that the cross-section of this intermediate part is made triangular with the outside arranged in parallel with the direction of the generatrix of the bearing surface 6a and the end section tapering out into a sharp edge in the direction of the working space 8. On the opposite side the intermediate part exhibits a side of the cross-section running radially, which bears against an axial stop 4b on the piston working member 4 against the axial component of the pressure prevailing in the working space 8. This pressure is transmitted by the elastic material of the connection region 12 of the sealing tube to the inside of the intermediate part 20. A radially expanding component of the pressure acting upon this annular body thereby also results, which in the case of appropriately elastic deform-ability may be made use of for direct participation of the outer face of the intermediate part and in particular of the edge section 22 of it ne~t to the working space, in the formation of a self-adjusting discharge throttle for the lubricant flowing along the bearing surface 6a from left to right in the sense of Figure 2. On the contrary a comparatively great stiffness against stretching of the ~annular body leads to an excessive constricti~e function or restraining function in respect of the elastic material of the connection region 12, so that the throttling action can be adjusted by radial bulging of the material of the seal independently of the more or less complicated shape of the .
' - , :: , ~, ,, : : . . ..
- :
~ .
profile of the axial section and of the area of vulcanization on the piston working member.
The radial prestress effect and the stiffness against stretching of the intermediate part can be adapted to the requirement at the time with the aid of auxiliary springs. Figure 2a sho-~s a comparatively weakly acting annular spiral tension spring 26 in the axial section through an annular intermediate part 20a having a trapezoidal profile. The auxiliary spring 26 is accommodated here in an outer circumferential groove in the annular body. Figure 2b shows a modified execution of the profile of an annular intermediate part 20b having lower radial extensibility because of a more massive shape of cross-section, furthermore because of a massive spring ring accommodated in a corresponding circumferential groove. Such an execution can scarcely be called upon for the formation of a throttle under radial expansion but brings about a stiff constriction and restraint of the connection region of the sealing tube against bulging under the working pressure.
The radially expandable executions as Figure 2 and Figure 2a offer on the contrary the further particular advantage that the annular body can during assembly be forced axially onto the piston which can be produced in one piece, past the greatest diameter of the axial stop 4b. On the other hand fitting is also possible o~ the smaller-diameter section of plston on the side next the working space, in the state before the vulcanization onto the connection region of the sealing tube. The centreing and embedding into the mass of the seal is then effected by the vulcanization.
In this case a connection of the substance of the material ,; . . ~ ' ~ ' ' ' ' ' : - ' :- ' 9 ~,43398 ," . .
does not readily result with the pla~tics ofthe intermediate part, but only to the surface of the piston working member.
A sufficient radial prestress leads nevertheless to sealing against the luhricant liquid from the clearance volume between the sealing tube and the bearing surface. On the other hand a certain admission under the annular body of the intermediate part, of the lubricant liquid under pressure, for assisting the radial expansion during throttle formation may be desirable.
In the case o~ the execution as in Figure 3 the intermediate part 30 is can-shaped and provided with a thinwalled and therefore easily stretchable wall part 32 extending along the bearing surface 6a, as well as with a thickwalled and stiff bottom or flange part 34. The latter is fastened by means of a thrust washer and a bolted joint (not shown) to the piston working member 4 and imparts radial stiffness to the outer end section of the wall part. The edge section 32a of the wall part 32 next the working space on the contrary expands comparatively widely radially under the action of the working pressure in the space 8 or respectively the corresponding pressure in the flexible material of the connection region 12 of the sealing tube and thus may form mainly or exclusively a self-adjusting throttle. If necessary for this purpose a shape of the wall part 32 may advantageously be provided which is already in the unstressed state slightly conical, diverging towards the working space.
For the rest the interior of the can-shaped intermediate part may if necessary be kept wholly or partially free of the material of the sealing tube if exp~nsion for the formation : ~
, ~ ~ - 1 o- 1~43398 of a throttle is effective in some other way. Under certain circumstances, for doing this the pressure of the lubricant entering from the clearance volume comes into consideration, which depends upon the pressure in the working space or respectively is in equilibrium with it.
Furthermore the heat-insulating action of the intermediate part is particularly advantageous, especially also the execution as in Figure 3 with its wide wall part, against a flow of heat from the cylinder or respectively - as regards the bottom part ~ from the driving cam with its heat of friction. This screening against additional heating contributes considerably to the resistance of the material of the tube in the connection region.
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Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Apparatus comprising two working members formed as a piston and a cylinder and being relatively movable, an elastic tube member sealingly engaging said working members at spaced locations and at least partially defining a working chamber, said tube member stretching and contracting and said working chamber varying in volume as said working members move relatively, said tube member having a surface portion sliding against a cylindrical supporting wall of a first one of said working members as the volume of said working chamber varies, and a ring member extending along the circumference of said tube member and located between said tube member and said supporting wall of said first working member in the region of connection of said tube member with the second one of said working members for limiting radial deformation of said tube member in direction towards said supporting wall of said first working member, said ring member being elastically deformable and having a radial prestress against said tube member.
2. Apparatus according to claim 1, in which said first working member is formed as said cylinder and said second working member as said piston being located at least partially within said cylinder and in which said supporting wall is formed as the inner wall of said cylinder, said working chamber being formed substantially within said tube member.
3. Apparatus according to claim 1, wherein a lubricant fluid flow is created between said tube member and said supporting surface, and said ring member is located in the area of discharge of said lubricant fluid flow from between said tube member and said supporting wall to a low-pressure exit space.
4. Apparatus according to claim 1, wherein said ring member is provided with spring means acting radially in direction towards said tube member.
5. Apparatus according to claim 1, wherein said ring member is supported at least partially by an axial stop integral with said second working member for preventing axial deformation of said ring member under the pressure in said working chamber.
6. Apparatus according to claim 5, wherein said ring member has a substantially triangular cross section with one side of said triangular cross section extending substantially parallel to said supporting wall, and another side of said triangular cross section extending radially from said one side in a direction away from said supporting wall.
7. Apparatus according to claim 1, wherein said ring member is can-shaped with a comparatively thin wall part extending along said supporting wall of said cylinder, and a comparatively thick wall part bearing against said tube member.
8. Apparatus according to claim 3, wherein said ring member forms throttle means for the discharge of said lubricant fluid flow to said low-pressure exit space.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH363379A CH639737A5 (en) | 1979-04-18 | 1979-04-18 | SEAL ON A PISTON CYLINDER ASSEMBLY. |
| CH3633/79-0 | 1979-04-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1143398A true CA1143398A (en) | 1983-03-22 |
Family
ID=4260170
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000350144A Expired CA1143398A (en) | 1979-04-18 | 1980-04-18 | Seal for a cylinder-piston arrangement |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4327629A (en) |
| EP (1) | EP0017787B1 (en) |
| JP (1) | JPS55139948A (en) |
| AT (1) | ATE5018T1 (en) |
| CA (1) | CA1143398A (en) |
| CH (1) | CH639737A5 (en) |
| DE (1) | DE3065235D1 (en) |
| ZA (1) | ZA802071B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108375103A (en) * | 2017-01-30 | 2018-08-07 | I.V.A.R.股份公司 | Device and method for adjusting heating system |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5052276A (en) * | 1990-06-18 | 1991-10-01 | Halsey George H | Diaphragm construction |
| JPH0618671U (en) * | 1992-08-04 | 1994-03-11 | 株式会社ケンウッド | Fluid pumping device |
| DK1173677T3 (en) * | 1999-04-22 | 2008-04-28 | Nvb Composites Internat A S | A device comprising a combination of a chamber and a piston |
| CN105604944A (en) * | 2015-12-18 | 2016-05-25 | 成都成发科能动力工程有限公司 | Compressor capable of changing critical speed of rotation of rotor and adjusting device thereof |
| JP6928192B1 (en) * | 2021-05-12 | 2021-09-01 | 株式会社三井Ｅ＆Ｓマシナリー | Piston pump |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US305214A (en) * | 1884-09-16 | Foueths to alvin shetjkeb | ||
| DE584025C (en) * | 1933-09-13 | Pfister & Langhanss Akt Ges | Self-closing flush valve that works with an auxiliary valve, counter pressure chamber, piston and roller sleeve | |
| US1085818A (en) * | 1909-03-10 | 1914-02-03 | Henry E Oxnard | Expansible chamber. |
| US2027979A (en) * | 1934-07-14 | 1936-01-14 | Kellogg M W Co | Boot pump |
| FR975545A (en) * | 1942-02-17 | 1951-03-06 | Improvements to elastically deformable hydraulic pistons and resulting new industrial product | |
| NL266067A (en) * | 1961-06-16 | |||
| FR1510437A (en) * | 1967-02-06 | 1968-01-19 | New type of master cylinder | |
| US3478649A (en) * | 1967-08-03 | 1969-11-18 | Bendix Corp | Sealed wheel cylinder |
| DE2554733C3 (en) * | 1974-12-17 | 1983-12-15 | Quadrupol AG, Glarus | Piston-cylinder arrangement with sealing hose |
-
1979
- 1979-04-18 CH CH363379A patent/CH639737A5/en not_active IP Right Cessation
-
1980
- 1980-03-21 AT AT80101488T patent/ATE5018T1/en not_active IP Right Cessation
- 1980-03-21 DE DE8080101488T patent/DE3065235D1/en not_active Expired
- 1980-03-21 EP EP80101488A patent/EP0017787B1/en not_active Expired
- 1980-04-08 ZA ZA00802071A patent/ZA802071B/en unknown
- 1980-04-09 US US06/138,573 patent/US4327629A/en not_active Expired - Lifetime
- 1980-04-18 CA CA000350144A patent/CA1143398A/en not_active Expired
- 1980-04-18 JP JP5222980A patent/JPS55139948A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108375103A (en) * | 2017-01-30 | 2018-08-07 | I.V.A.R.股份公司 | Device and method for adjusting heating system |
Also Published As
| Publication number | Publication date |
|---|---|
| US4327629A (en) | 1982-05-04 |
| ATE5018T1 (en) | 1983-10-15 |
| JPS6357625B2 (en) | 1988-11-11 |
| EP0017787B1 (en) | 1983-10-12 |
| JPS55139948A (en) | 1980-11-01 |
| DE3065235D1 (en) | 1983-11-17 |
| EP0017787A1 (en) | 1980-10-29 |
| CH639737A5 (en) | 1983-11-30 |
| ZA802071B (en) | 1981-05-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |