Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3598095 A
Publication typeGrant
Publication dateAug 10, 1971
Filing dateOct 2, 1969
Priority dateOct 2, 1969
Publication numberUS 3598095 A, US 3598095A, US-A-3598095, US3598095 A, US3598095A
InventorsAyres H Vincent
Original AssigneeEaton Yale & Towne
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Hydraulic valve lifter with temperature compensating lubricant metering means
US 3598095 A
Abstract  available in
Images(1)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

United States Patent 000000000 999999999 333333333 222222222 llllillll.

t .t m w H n 8 r r a Pn i n .JJ h o m slqlq k o vn 0 Cmdd m h a .m 0 u y b b BTDLVKAAA 389946699 355566666 999999999 HHHHHHHH 721237846 1 27544800 95583 83 J 650442778 67726634 v m y vl fl w 22233333 w mm I HM A...- 7 80 QM n a n 9 d awMJQYM mmn ww w w m H 8 A C r 0. de m N. m e e v Wham .m AFPA .1 11]] 2 1253 7 2247 I [[[i [54] HYDRAULIC VALVE LIFTER WITH Primary Examiner-Al Lawrence Smith TEMPERATURE COMPENSATING LUBRICANT Attorney-Your and Tarolli METERING MEANS 3 Claims,4 Drawing Figs.

An improved hydraulic valve lifter has a socket member and a body member with cooperating surfaces which define a metering passageway therebetwee flow of oil to an associated rocker arm asse member has a higher coefficient of expansl member. Therefore, when the temperature of the oil and the socket member increases the socket member will ex tive to the body to decrease the cross tering passageway. Since the cross-sectional area of the metering passageway decreases as the temperature of the oil increases, the flow rate of the oil tends to remain constant even though the viscosity of the oil decreases.

T C A R T S B A 5 4 03 s n m m W wl 304 m l .l 0M 7; HJFF 51 0 0 5 m m vw n w "0 n m m mm m6 m m m m MS m .n 2 C m m3 m m m n no u m m n m m e u "3 d M MD R n T1, m mm L r C o t m S m k U I. F 1 1 l l 2 I. 0 6 5 5 5 5 l l I .1

x ll 4 I .-i E

PATENTED AUG 1 01971 ME 5 m. M rm m A w W r N E w w w H 2 .6 El

HYDRAULIC VALVE LIFTER WITH TEMPERATURE COMPENSATING LUBRICANT METERING MEANS The present invention relates to a hydraulic valve lifter, and more particularly to a hydraulic valve lifter which is operable to meter a flow of lubricant from the hydraulic valve lifter to the rocker arm assembly of an internal combustion engine.

Known hydraulic valve lifters are provided with metering means for controlling the flow of lubricant from the lifter to a rocker arm assembly. Such lifters are exemplified by the lifters disclosed in Line Pat. No. 3,476,093 and in the Abell Pat. No. 3,448,730 both assigned to the same assignee as the present invention.

Known lifters include a metering fluid passageway through which lubricating fluid flows to the rocker arm assembly. The valve lifters have been constructed so that the cross sectional area of the metering passageway remains substantially constant with temperature changes. As a result, as temperature increases there is a greater flow of lubricating fluid through the metering passageway due to decreased viscosity of the fluid. This results in a variable flow of lubricating fluid with temperature changes. As a result, in the known lifters, there is frequently either too great a flow of fluid from the lifter at high temperatures, or too little a flow of fluid at low temperatures.

In accordance with the present invention, the flow passageway through which the lubricating fluid flows varies in cross-sectional dimension upon temperature changes. At low temperatures, the flow passageway is of its greatest size and the flow passageway decreases in size as the temperature increases. Accordingly, the flow passageway cross-sectional area changes, namely, decreases, as the viscosity of the fluid increases. As a result, the flow of fluid through the metering passageway can be maintained substantially constant. In accordance with the present invention, the change in the crosssectional area of the metering passageway is effected by manufacturing the parts defining the passageway of materials having difl'erent coefficients of expansion.

Accordingly, the principal object of the present invention is to provide a new and improved hydraulic valve lifter having a metering passageway through which fluid for lubricating a rocker arm assembly flows, and wherein the cross-sectional area of the metering passageway is controlled with changes in temperature so as to provide for a substantially constant flow of lubricating fluid to the rocker arm assembly.

A further object of the present invention is to provide a new and improved hydraulic valve lifter having a metering passageway with a cross-sectional area which decreases as the temperature of the valve lifter increases to thereby at least partially control the flow of lubricant to the rocker arm assembly associated with the valve lifter.

Another object of the present invention is to provide a new and improved hydraulic valve lifter having a body member, a socket member located in the body member, and a metering passageway defined by cooperating surfaces of the socket member and the body member and wherein the socket member has a higher coefficient of expansion than the body member which causes the socket member to expand faster than the body member as the temperature of the valve lifter increases to thereby effect a decrease in the cross-sectional area of the metering passageway as the temperature of the valve lifter increases.

A further object of the present invention is to provide a new and improved hydraulic valve lifter, as noted in the next preceding paragraph, wherein the increase in temperature of the valve lifter which effects the decrease in size of the metering passageway also causes a decrease in the viscosity of the fluid to be metered, and wherein the decrease in cross-sectional area of the metering passageway compensates for the decrease in the viscosity of the fluid to be metered so that the flow of metered fluid through the metering passageway is substantially constant.

A still further object of the present invention is to provide a new and improved hydraulic valve lifter having a socket member having a fluid passageway therein for directing fluid from a fluid reservoir located in the hydraulic valve lifter, a metering passageway for metering the flow of fluid to the fluid passageway and wherein the metering passageway decreases in cross-sectional area as the temperature of the valve lifter increases to thereby compensate for the decrease in viscosity of the fluid due to the increase in the temperature thereof.

Further objects and advantages of the present invention will be apparent from the following description of a preferred embodiment of the present invention made with reference to the accompanying drawings forming a part of the specification and wherein:

FIG. 1 is a schematic view of a hydraulic valve lifter and related assemblies in an engine block;

FIG. 2 is a cross-sectional view of a preferred embodiment of the invention taken approximately along the lines 2-2 of FIG. 1;

FIG. 3a is an enlarged cross-sectional view of a portion of the hydraulic valve lifter illustrated in FIG. 2 showing the rela tively large cross-sectional area of the metering passageway when the socket member has a low temperature; and

FIG. 3b is a view similar to FIG. 3a but showing the relatively small cross-sectional area of the metering passageway when the socket member has a high temperature.

The present invention provides an improved hydraulic valve lifter, and particularly an improved metering means for metering the flow of lubricant or oil from the lifter to a rocker arm assembly of an internal combustion engine. The metering means includes cooperating surfaces located on the socket member and valve lifter body. The cooperating surfaces define a metering passageway which meters the flow of lubricant from the valve lifter to the rocker arm assembly. The socket member is constructed of a material having a higher coefficient of expansion than the material of which the body member is constructed so that an increase in temperature of the socket member and the expansion thereof effects a decrease in size of the metering passageway. The present invention may be embodied in valve lifters of a variety of constructions and by way of example a hydraulic valve lifter l0, embodying the present invention, is illustrated in FIG. 1.

The hydraulic valve lifter 10 controls the movement of an engine valve 20. The valve 20 controls the flow of gases into and from the combustion chamber 14 of a cylinder of the engine. The valve member 20 is moved between the open and closed positions with respect to a valve seat 20a by a valve gear, generally designated 21.

The valve gear 21 is actuated by a cam 9 which engages the hydraulic lifter 10. The cam 9 consists of a circular portion 11 and a raised portion 13, which rotate with a cam shaft 12. The bottom portion of the lifter 10 engages the cam 9 which imparts motion to the lifter during its rotation. The cam 9 rotates in a clockwise direction and an upward motion is imparted to the lifter 10 as the ramp 13a of the cam 9 engages and moves relative to the lifter 10. An upward motion of the lifter If) ef fects an upward movement of the valve gear 21 and an opening of the valve 20. When the ramp 13!; engages with and moves relative to the lifter 10, a downward movement of the lifter I0 and of the valve gear 21 is effected. The downward movement of the valve gear 21 closes valve 20 and it engages the valve seat 20a.

A push rod 15 is interposed between the lifter I0 and a rocker arm 17. Movement of the push rod 15 by the lifter 10 causes the rocker arm I7 to pivot about bearing 18 and effect opening or closing of the valve 20. The push rod 15 has a tubular inner passageway 16 which allows lubricant to flow therethrough from the valve lifter 10 to the bearing 18 of the rocker arm. When the rocker arm 17 is raised by an upward movement of the push rod 15 acting upon a shoulder 17a thereof, the rocker arm 17 pivots about the bearing 18 and a shoulder 17b of the rocker arm 17 exerts a downward force to open the valve 20. A spring 19 biases the shoulder 17b upwardly so that when the ramp 13b engages with the bottom of the lifter, the spring 19 effects an upward movement on member 30 has a closed end 31 which is engaged by the cam 9 as shown in FIG. 1. Disposed within the hollow body member 30 are a plunger member 32 and a push rod socket member 33. Seated within the push rod socket on a push rod seat 34 is the push rod 15. A snap ring 41 is disposed in an annular groove 41a in the portion 35 of the hollow body member 30 to hold the parts of the lifter within the body member 30.

The plunger member 32 at least in part defines a lubricant reservoir 40. Lubricant such as oil is pumped into a passageway 42 in the portion 35 of the body member 30 by some suitable means not illustrated, such as a pump. The passageway 42 communicates with an annular groove 43 in the portion 35 of the body member 30 which in turn communicates with a passageway 45 in the plunger member 32 to allow lubricant to flow into the reservoir 40. Therefore. during normal operations the reservoir 40 is filled with lubrica nt.

The reservoir 40 communicates with a lower rressure chamber 52 by means of a passageway 46 located in the lower end of the plunger member 32. Disposed within the pressure chamber 52 is a check valve 47. The check valve 47 rests within a check valve retaining cup 48 suitably connected to the plunger member 32 at the shoulder 49. The check valve 47 is biased into engagement with a valve seat 47a formed on the lower end of the plunger member 32 by a spring means 50 attached to the bottom of the check valve retainer cup 48.

When the hollow body member 30 is moving in a downward direction, the check valve 47 tends to open and allow lubricant to flow from the reservoir 40 through passageway 46 into the pressure chamber 52. The check valve 47 opens when the chamber 52 enlarges with a'corresponding reduction in pressure therein. The enlargement of chamber 52 is effected by the plunger spring 51 which biases the plunger 32 away from the bottom portion 31 of the body member 30. During a downward motion of the lifter the forces acting thereon are such that the spring 51 effects enlargement of the pressure chamber 52, as is well known. The drop in pressure in chamber 52 leaves the check valve 47 with unbalanced forces acting thereon. The pressure acting on check valve 47 from the reservoir 40 is much greater than the pressure in chamber 52 and overcomes the force of the spring 50 and the pressure in the chamber 52 to open the check valve 47. When the body member 30 moves upwardly the fluid pressure in the chamber 52 is increased. The pressure increase in chamber 52 tends to push the check valve 47 against the valve seat 47a, thus sealing the pressure chamber 52 from the reservoir 40.

When the check valve 47 closes passageway 46 due to an upward movement of the body member 30, the lubricant in the pressure chamber 52 is essentially sealed therein. The lubricant sealed within the pressure chamber 52 is substantially incompressible and therefore when the hollow body member 30 is raised, the lubricant within the pressure chamber 52 will exert an upward force which resists downward movement of the plunger member 32 relative to the body member 30. As a result, the plunger member 32 moves in an upward direction, thus opening the valve as described hereinabove. During each valve opening stroke, a small amount of lubricant trapped in the pressure chamber 52 escapes or leaks around the plunger through a small space 60 disposed between the body member and the plunger member. This leakage is termed "leak-down and is necessary in order to insure that the valve 20 can be fully seated on the subsequent return stroke which occurs with a continued rotation of the cam 9. Were it not for this leak-down" during r-ach lifting stroke and any of the parts of valve train lengthened due to an increase in temperature, such greater length would hold the engine valve 20 slightly off its seat 20a.

The plunger member 32 is disposed to abut the socket member 33 at the bottom portion 53 thereof and the plunger return spring 51' biases the plunger into engagement with the socket 33 during normal operation. Therefore, an upward movement of the plunger member 32 causes an upward movement of the socket member 33. This upward movement of the socket member causes the push rod 15 which is engaged upon the push rod seat 34 of the socket member to move upwardly. The upward movement of the push rod 15 and its opening of valve 20 has been described hereinabove.

The hydraulic lifter 10 provides for lubricant flow through the push rod passage 16 to the rocker arm 17. To this end, the socket member 33 has an annular peripheral surface 38 upon which is located an inlet 38a. A radially extending passageway 37 is interposed between the inlet 38a and a perpendicular passageway 36. The passageway 36 has an outlet 36a in communication with the push rod seat 34. Spaced from the annular groove 43 is a groove 61 which includes an O-ring seal 610 which cooperates with the body member 35 and socket member 33 to prevent the free flow of lubricant therepast. The passageways 36, 37 and the openings 38a, 36a allow lubricant to flow from the reservoir 40 through the passageways to the passageway 16 within the push rod 15 and to the rocker arm 17.

In accordance with the present invention, the hydraulic valve lifter ll) includes means for metering the flow of lubricant from the reservoir 40 through the push rod 15 and to the rocker arm 17. The metering means'includes a surface 62 (FIG. 3a) of the socket member 33 and the surface 64 of the portion 35 of the body member. The surfaces 62 and 64 cooperate to define a metering passageway 66 disposed therebetween for. metering the flow of the lubricant from the reservoir 40 to the passageway 37 in the socket member 33. The flow of lubricant is metered by controlling the cross-sectional area of the metering passageway 66 which is proportional to the difference in the outer diameter of the socket member 33 and the inner diameter of the upper portion of the body member 35. By varying the outer diameter of the socket member 33 or the inner diameter of the upper portion 35 of the body member the separation between thesurfaces 62 and 64 can be varied thus, varying the cross-sectional area of the metering passageway 66. i

The socket member 33 is constructed of a material which has a higher coefficient of expansion then the material of which the body member is constructed. The high coefficient of expansion of the socket member 33 effects an increase in the outer diameter of the socket member 33 when the tem perature of the socket member is raised. Since the coefficient of expansion of the socket member 33 is higher than the coefficient of expansion of the body member 30, the socket member expands faster than the body member when the temperature of the lifter 10 is raised. The faster expansion of the socket member 33 causes the outer diameter of the socket member to increase to thereby decrease the cross-sectional area of the metering passageway.

It should be apparent that the temperature of the socket member 33 will vary depending upon the mode of operation of the engine within which the valve lifter 10 is mounted. When the engine is not operating the temperature of the socket member 33 will be relatively low. However, when the engine is started the temperature of the socket member 33 will increase due to the friction caused by movement of the valve lifter l0 and the parts therein. Further increases in the speed of operation of the engine and the increased friction associated therewith will cause a still further rise in the temperature of the socket member 33. As the temperature of the socket member increases, the outer diameter of the socket member 33 will also increase, causing a reduction in the cross-sectional area of the metering passageway 66. Thus, it should be apparent that when the engine is initially started and relatively cold the cross-sectional area of the metering passageway 66 will be much greater than the cross-sectional area of the metering passageway 66 after the engine has been run for a short period of time and is relatively hot. This is a result of a high coefficient of expansion of the socket member 33.

Generally, the viscosity of the lubricating fluid used to' lubricate the rocker arm 17 varies with the temperature of the fluid. At low temperatures the viscosity of the lubricating fluid is high, but as the temperature of the fluid increases the viscosity will decrease. Thus, when the engine is cold and the lubricating fluid is relatively thick or viscous, the socket member 33 is contracted relative to the body member 35 so that the metering passageway 66 is relatively large (FIG. 30). Therefore, the relatively viscous lubricating fluid can flow at a desired rate through the metering passageway to the rocker arm 17. When the engine is warmed up and the lubricating fluid is relatively thin, the socket member 33 is expanded relative to the body member 35 so that the metering passageway 66 is relatively small (FIG. 3b). Therefore, the flow of the relatively thin, low viscosity lubricating fluid is restricted so that the desired flow rate is not substantially exceeded. Thus, the use of materials having different coefficients of expansion enables the size of the metering passageway 66 to be varied with variations in temperature to provide a substantially constant flow of lubricating fluid to the rocker arm 17.

The socket member 33 may be constructed of a wide range of materials which have a high coefficient of expansion. To this end a material such as 18-8 stainless steel may be used. Generally, stainless or austenitic steel expands clue to a temperature increase at approximately 150 percent of the rate at which ferritic steels expand. Therefore, the utilization of a stainless steel socket member with a ferritic steel body member will effect a decrease in the cross-sectional area of the metering passageway 66 by lessening the clearance between the outer diameter of the socket member 33 and the inner diameter of the upper portion of the body member 30 when the temperature of the valve lifter is increased. Thus, the provision of a stainless steel socket member and a ferritic steel body member will provide for a constant flow of lubricant as disclosed hereinabove.

It should be realized that the provision of a constant flow of lubricant to the rocker arm assembly 17 is desirable in most engines. To this end, the coefficient of expansion of the socket member 33 must be chosen in view of the coefficient of expansion of the body member 30 and the type of lubricant that is to be used in the valve lifter 10. The provision of a socket member having a proper coefficient of expansion will allow the cross-sectional area of the metering passageway to vary as the viscosity of the lubricant varies to thereby provide a constant flow of lubricant to the rocker arm assembly.

While a preferred embodiment of the present invention illustrates a constant flow of lubricant to the rocker arm assembly 17, it should be apparent that a nonconstant flow of lubricant could also be provided by the utilization of a socket material having a higher coefficient of expansion. This may be desirable in certain situations wherein a higher flow of lubricant to the rocker arm assembly 17 is needed due to higher operating temperatures of the engine. Therefore, it should be apparent that the flow rate of lubricant may be controlled by the relationship of the coefficient of expansion of the socket member 33, the coefficient of expansion of the body member 30 and the characteristics of the lubricating fluid that is used to lubricate the valve train 21.

Moreover, it should be apparent that a metering members disclosed in the Line Pat. No. 3,476,093 could also be utilized in the present invention to decrease the cross-sectional area of the metering passageway 66 when the temperature of the lifter increases. The metering member could be disposed so as to meter the flow of lubricant into the passageway 37. The metering member would be constructed of a material hiving a high coefficient of expansion so that the flow of lubricant through the socket member would decrease as the metering member expands due to an increase in temperature. Thus, as the temperature of the metering member was increased due to the friction acting on the hydraulic valve lifter 10, the metering member would expand and tend to decrease the effective cross-sectional area of the metering passageway. Clearly, as

discussed hereinabove the expansion of the metering member would occur as the viscosity of the lubricant decreased so that a constant flow of lubricant could be provided to the rocker arm assembly if it is so desired.

From the foregoing it should be apparent that a hydraulic valve lifter has been provided which has a metering passageway therein for metering the flow of lubricant from the hydraulic valve lifter to the rocker arm of an internal combustion engine. The socket member and the body member have cooperating surfaces which define the metering passageway therebetween for metering the flow of lubricant. The socket member is constructed of a material which has a higher coefficient of expansion than the material from which the body member is constructed and the metering is provided by controlling the clearance between the outside diameter of the socket member and the inside diameter of the body member. When the valve lifter and the lubricant are cold the lubricant has a high viscosity and there exists a relatively large clearance between the socket member and the body member which provides a metering passageway having a relatively large cross-sectional area. However, as the engine tempera ture increases and the viscosity of the lubricant decreases, the socket expands more rapidly than does the body member so that a decrease in the cross-sectional area of the metering passageway is effected. Thus, a substantially constant flow of lubricant to the rocker arm is provided by controlling the cross-sectional area of the metering passageway as the viscosity of the lubricant varies.

What I claim is:

1. A hydraulic valve lifter for use in a valve train including a rocker arm assembly, said hydraulic valve lifter comprising a body member made of a material having a first coefficient of expansion, and a socket member located at least partially within said body member and made of a material having a second coefficient of expansion which is greater than said first coefficient of expansion, said socket member having a first fluid passageway therein for directing lubricating fluid therethrough to the rocker arm assembly, said socket member and said body member having cooperating surfaces which define a second fluid passageway for continuously metering a flow of lubricating fluid to the rocker arm assembly, said socket member being expandable relative to said body member in response to an increase in temperature to decrease the cross-sectional area of said second fluid passageway and to thereby control to' at least a limited extent the flow rate of lubricating fluid to the rocker arm assembly as the temperature of the valve lifter and lubricating fluid increases.

2. A hydraulic valve lifter as defined in claim 1 wherein the cross-sectional area of said second passageway and the viscosity of the lubricating fluid varies with changes in temperature in such a manner that the lubricating fluid has a high viscosity and said second passageway has a relatively large cross-sectional area at a relatively low temperature and the lubricating fluid has a low viscosity and said second passageway has a relatively small cross-sectional area at a relatively high operating temperature.

3. A hydraulic valve lifter as defined in claim 2 wherein changes in the cross-sectional area of said second passageway with changes in temperatures are such as to provide for a substantially constant flow of lubricating fluid to the rocker arm assembly even though the viscosity of the lubricating fluid changes with changes in temperature.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1727790 *Apr 21, 1927Sep 10, 1929Gen Motors Res CorpHydraulic slack adjuster
US1916191 *Nov 27, 1931Jul 4, 1933Gen Motors CorpZero lash valve lifter
US2865352 *Dec 5, 1955Dec 23, 1958Thompson Earl ATappet construction
US2870757 *Jul 30, 1956Jan 27, 1959Dayton Ernest LHydraulic valve tappet
US2874685 *Aug 26, 1955Feb 24, 1959Eaton Mfg CoHydraulic valve lifter
US3124114 *Aug 5, 1960Mar 10, 1964 Voorhies
US3262434 *Feb 27, 1964Jul 26, 1966Motomak Motorenbau MaschinenunSelf-adjusting hydraulic valve lifter for piston engines
US3267918 *Aug 3, 1964Aug 23, 1966Eaton Mfg CoFluid metering valve structure
US3437080 *Nov 13, 1967Apr 8, 1969Eaton Yale & TowneValve tappet
US3448730 *Jun 7, 1967Jun 10, 1969Eaton Yale & TowneHydraulic valve lifter
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3717134 *Sep 13, 1971Feb 20, 1973Johnson Products IncTappet push rod seat and meter means
US3782345 *Jun 3, 1971Jan 1, 1974Johnson Products IncMetered mechanical tappet with slotted push rod seat
US3838669 *Aug 11, 1972Oct 1, 1974Johnson Products IncHydraulic lash adjuster
US4009696 *Nov 20, 1975Mar 1, 1977Sealed Power CorporationHydraulic lash adjuster with internal oil pressure control
US4083334 *Mar 11, 1974Apr 11, 1978Carlos Alberto Ferrari RonconHydraulic valve lifter
US4867113 *Dec 27, 1988Sep 19, 1989Ford Motor CompanyReduced friction engine tappet construction
US6039018 *Feb 18, 1999Mar 21, 2000General Motors CorporationHydraulic lash adjuster with plunger inner control ring
US6119644 *Jan 18, 2000Sep 19, 2000Ina Walzlager Schaeffler OhgHydraulic clearance compensation element
US6626137 *Jan 14, 2002Sep 30, 2003Caterpillar IncAutomatic lash adjuster
Classifications
U.S. Classification123/90.35, 123/90.51, 184/6.9, 123/90.55, 184/6
International ClassificationF01L1/245, F01L1/20
Cooperative ClassificationF01L1/245
European ClassificationF01L1/245