US 2790520 A
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Description (OCR text may contain errors)
April 30, 1957 Filed Aug. 2, 1954.
SEAL FOR WINGS R MOVING VANES OF DAMPERS William A. Kuhn, Jr., Detroit, Miclr, assignor to Houdaille Industries, lnc., Detroit, Mich, a corporation of Michigan Application August 2, 1954, Serial No. 447,141
(Ilaims. (Cl. 188-93) The present invention relates to improvements in structures useful in rotary type shock absorbers, flutter dampers, steering motors and the like.
An important object of this invention is to provide new 2 d improved vane sealing means for rotary type shock absorbers, and the like, for preventing fluid leak-by during operation.
Another object is to provide a new and improved seal structure between the vanes and cylinder walls of rotary hydraulic shock absorbers or dampers, and the like affording a novel wiping, squeegee-like action in operation.
Still another obiect is to provide improved means for preventing leak-by of fluid past the fluid moving vanes or piston in a rotary shock absorber, damper or similar rotary vane device.
Qther obiects, features and advantages of the present inventi n will readily apparent from the following detailed description of a preferred embodiment thereof taken in conjunction with the accompanying drawing, in which:
Figure l is a more or less schematic, cross-sectional view through a rotary vane shock absorber or damper embodying the novel features of the instant invention;
Figure 2 is a perspective view of the rotary piston or hub and vane structure of the shock absorber;
Figure 3 is an enlarged fragmentary view of the terminal portion of one of the vanes or wings of the rotary piston; and
Figure is a view similar to Figure 3 showing the action of the instant sealing means in operation.
The novel features of the instant invention are especially useful in conjunction with rotary piston devices such as rotary vane or piston hydraulic shock absorbers, vibration dampers, flutter dampers, steering vane or piston motors, and the like, wherein a varied piston is rotatable within a hydraulic working space circumscribed by a cylindrical wall.
As shown by way of example, more or less schematically, in Figure l, a cylindrical housing 10, has means therein defining a hydraulic working space, in the instant embodiment comprising diametrically opposed radially inwardly projecting abutment members 11, 11. The abutmerit members ll, 11 in conjunction with the cylindrical housing 33 define hydraulic working spaces l2, 12. A piston shaft 13 is rotatably disposed within the working space l2, 12 between the abutment members 11, 11. The l3 and the housing Iii are adapted to be connected to. relatively torsionally movable members or structures.
A pair of diametrically opposed fluid moving vanes 14, is formed integrally with the shaft 13 to project radially outwardly therefrom. The frusto-conical vanes or Wings 14- have their distal or terminal portions 15 curved complementarily to coincide with the contour of the inner periphery 1 3:: of the cylindricalhousing lit. The curved terminal portions 15 of the vanes 14 are thus adapted for close cooperative though not necessarily sliding coopera- "ice tion with the inner periphery 10a of the cylindrical housing 10.
The wing shaft 13 and the vanes 14 are rotatable within the work space 12 of the cylindrical housing 10 and define hydraulic chambers 16, 17, 18 and 19 in conjunction with the abutment numbers 11, and the cylindrical housing 10.
Displacement and movement of the hydraulic fluid between the chambers 16, 1'7, 18 and 19 during rotational movement of the vanes 14 is provided for by passageways 21, 22, 23 and 24 and is controlled by a valve V in a well known manner.
The curved distal terminal portions 15 of the vanes 14 have a groove 25 formed therein which preferably extends axially the entire length of the vanes 14. The groove 2% has generally radially outwardly tapering walls, 26 and 27 and confronts the inner periphery 10a of the cylindrical housing 19. As seen best in Figures 3 and 4, the groove 25 has a generally triangular or V-shape configuration, Since the sides 26 and 27, of the groove-25 are of substantially equal length, the groove 25 may be said to have the general shape of an isosceles or equilateral triangle. That is, the groove 25 has a generally triangular shape wherein at least two sides of said triangle are of equal length.
Means are provided in the grooves 25 to prevent the lealoby of hydraulic fluid when the vanes 14 are rotated. Such means, as shown in the drawings, preferably comprise an elongated, resilient sealing member 28. The resilient sealing member 28 is preferably of a generally triangular cross-sectional configuration. As in the case of the groove 25, the sealing member 28 is preferably of an equilateral or isosceles triangular cross-sectional shape wherein at least two of the sides of the triangle are of equal length, while the base or bottom portion 3.0 of the triangular sealing member 28 is preferably concave or arcuately shaped in opposition to the curvature of the inner periphery Ilia of the housing 10.
The sealing member 28 preferably extends the entire length of the vane 14.
The material from which the seal member 28 is formed is not critical and can vary so long as the material is sufficiently resilient and has the other appropriate characteristics and properties necessary to effect a proper seal between the chambers 16 and 17, and 18 and 19, when the vanes 14 are rotated, as will be explained more fully hereinafter, The preferred material, however, is one which is resilient, wear resistant and resistant to the chemical action of oil and similar materials most commonly employed as hydraulic fluids. Among the materials which may be employed in producing the sealing member 28 are extruded nylons or similar long chain synthetic polymeric amides. Other suitable resilient or elastromeric substances for this purpose are the so-called synthetic rubbers or oil resistant rubber substitutes which may be produced by:
(A) Polymerization of butadiene alone or with styrene;
(B) Inter-reaction between sodium polysulfides and dihalides;
(C) Polymerization of chloroprene;
(D) Polymerization of isobutadiene;
(E) Polymerization and plasticisation of vinyl chloride.
The triangular sealing member 28 is disposed within the triangular groove 25 so that the apex portion of the triangular sealing member 28 is pivotally engaged or fulcrumed on the apex portion of the triangular groove such as at 29. In a preferred embodiment this arrangement provides superposed isosceles triangles, wherein the legs or sides of the seal 28 describe a slightly smaller angle than do the sides 26 and 27 of the groove 25. This differential angularity provides a space between the sides of the sealing member 28 and the walls of the groove 25. As seen best in Figure 3, when the vane 14 is in stationary or non-rotating position substantially all of the base portion 30, except. for the ends thereof, is in arcuate spaced relationship from the inner periphery a of the cylindrical housing 10. Only the tapered end portions 31 and 32 of the base portion 30 are in contact with the inner periphery 10a of the housing 10. The end portions 31 and 32 aflord virtually line contact in sealing the terminal portions of the vanes 14 when at rest or during slight movement of the vanes.
This virtually line sealing contact of the marginal wiping edges 31 and 32 presents a minimum amount of frictional engagement with the inner surface 10a of the housing 10 during normal damping movement of the vanes 14. When, however, the vanes 14 are subjected to a fluid moving force, the differential flare or angularity existing between the sealing member 28 and the walls of the groove 25 causes the sealing member 28 to cant by fulcruming on its apex as at 29. This canting of the sealing member 28, as in Figure 4, causes the trailing wall, such as 27, of the groove 25 to exert pressure against the sealing member 28. This pressure, in turn, causes the leading marginal edge of the sealing member 28, such as 32, to be resiliently deformed. This deformation brings a much larger portion of base 30 into wiping engagement with the inner surface 10a of the housing resulting in an increased sealing effect between the vane 14 and the housing 10. In addition the back pressure exerted by the fluid being displaced by the advancing vane also aids in resiliently deforming the sealing member 28 into greater wiping sealing contact with the inner surface 10a of the housing 10.
This novel triangular shape of the seal member 10 is designed so that scaling is a function of the applied pressure. That is, the higher the pressure exerted by the canting action against the side of the seal member 28 the greater the resilient deformation and the greater the corresponding sealing effect. In this manner an eflicient seal between the terminal portion 15 of the vane 14 and the inner periphery 10a of the cylindrical housing 10 is effected advantageously, and leak-by of hydraulic fluid around the terminal portions of the vanes 14 is effectively reduced.
Although in the preferred embodiment the groove 25 hasbeen shown as formed on the terminal portion of the vane, it will be understood that the groove 25 could be formed in the inner periphery 10a of the housing 10 and have the sealing member 28 disposed therein.
Heretofore, it has been extremely diflicult to prevent leak-by of hydraulic fluid in shock absorbers of the instant type. Such shock absorbers which have been produced hitherto have had to rely upon extremely close tolerances between the terminal portions of the vanes and the inner periphery of the cylindrical housing or have resorted to bulky seals which materially increased friction to minimize and control leak-by. In spite of the extremely close tolerances employed, however, it has been substantially impossible adequately to control leakby.
By means of the novel features of the instant invention, however, it is now possible to produce vanes, Wings or pistons in the rotary type devices without observing close tolerances and without creating undesirable amounts of friction in order to control leak-by. The instant invention now minimizes expensive and time-consuming machining operations to assure close tolerances between the terminal portions of the vanes and the inner periphery of the housing. The novel resilient sealing means of this invention adequately compensate for any gap existing between the vane and housing inner periphery and do so without increasing friction to any appreciable extent. It will be understood that modifications and variations maybe effected without departing from the scope of the novelconcepts of the present invention.
I claim as my invention:
1. In an article of the class described, a rotary piston member having a fluid displacing vane having its distal terminal cooperatively related to an arcuate wall forming a part of a working chamber, said distal terminal having a generally triangular longitudinal groove extending therealong, and a resilient generally triangular sealing member rockingly carried in said groove and having a concave surface facing the arcuate wall of the working chamber, the opposite marginal edges of which have wiping engagement with said wall accommodating free rocking movement of said vane along said wall and providing a seal of increasing sealing area upon increases in pressure thereagainst.
2. In an article of the class described, a cylindrical housing, means defining a working space within said housing, a rotary piston member within said working space, and having a fluid displacing vane having a distal terminal end in curved complemental relationship with the inner peripheral surface of said cylindrical housing, said distal terminal having a groove extending therealong and opening to the inner peripheral surface of said housing, and a resilient sealing member freely and rockingly carried within said groove, said sealing member having opposite longitudinal marginal projections having wiping engagement with the inner peripheral surface of said cylindrical housing and being freely resilient throughout its entire cross sectional area and accommodatingfree rocking movement of said vane in said working space and pressing against said inner peripheral surface of said housing with increasing sealing area as the pressures against said sealing member increase.
3. In a rotary hydraulic shock absorber, a cylindrical housing, means defining 'a working space Within said cylindrical housing, a piston rotatably disposed within said working space, a fluid moving vane integral with said piston and projecting radially therefrom, said vane having the terminal portions thereof in close complemental curved relationship with the inner periphery of said cylindrical housing, means defining an axially extending generally triangular groove on said terminal portion of said vane confronting said inner periphery of said cylindrical housing, and a triangular resilient sealing member tiltably disposed within said groove, said sealing member having respective opposite longitudinal marginal projections having line sealing contact with said inner periphery of said cylindrical housing and resiliently deformed against said inner periphery with increasing sealing area in sliding sealing contact therewith as the pressures thereon increase.
4. In a rotary shock absorber, a cylindrical housing, means defining a working space within said cylindrical housing, a piston rotatably disposed within said working space, a fluid moving vane integral with said piston and projecting radially therefrom, said vane having the terminal portion thereof in close complemental curved relationship with the inner periphery of said cylindrical housing, said vane having an axially extending generally isosceles triangular groove on the terminal portion there of confronting the inner periphery of said cylindrical housing, and an elongated resilient generally isosceles triangular sealing member disposed within said groove and having the apex thereof pivotally engaged with the apex of said triangular groove, said triangular sealing member including a concave base portion having respective opposite longitudinal marginal projections wipingly cooperative with the inner periphery of said cylindrical housing, said projections being adapted to be deformed resiliently against said inner periphery of said cylindrical housing with increasing sealing area when said vanes are rotated as the pressures thereon increase, and thereby to prevent leak-by of fluid past the terminal portions of said vanes.
5. In combination with a housing having a cylindrical wall and a rotatable piston in said housing having a vane movable along said wall, variable pressure sealing means between said vane and said wall comprising a generally V-shaped groove extending along said vane and opening toward said wall and having a resilient sealing member carried therein, said sealing member being generally triangular in cross sectional area the angle at the apex of 5 which is smaller than the angle at the apex of said groove and having a concave base the edges of which have line contact with said wall and have increasing sealing engaging area with said wall on the edge thereof facing the direction of rotation of said vane as the pressures thereon 10 increase.
References Cited in the file of this patent UNITED STATES PATENTS