EP0100241B1 - Hydraulic lash adjustor in a valve operating mechanism - Google Patents
Hydraulic lash adjustor in a valve operating mechanism Download PDFInfo
- Publication number
- EP0100241B1 EP0100241B1 EP19830304368 EP83304368A EP0100241B1 EP 0100241 B1 EP0100241 B1 EP 0100241B1 EP 19830304368 EP19830304368 EP 19830304368 EP 83304368 A EP83304368 A EP 83304368A EP 0100241 B1 EP0100241 B1 EP 0100241B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- plunger
- valve
- operating mechanism
- hydraulic
- valve operating
- 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
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- 239000010720 hydraulic oil Substances 0.000 claims description 16
- 230000002093 peripheral effect Effects 0.000 claims description 6
- 230000007423 decrease Effects 0.000 claims description 4
- 230000000881 depressing effect Effects 0.000 claims description 2
- 238000006073 displacement reaction Methods 0.000 description 11
- 238000003754 machining Methods 0.000 description 4
- 230000006378 damage Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 208000027418 Wounds and injury Diseases 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000000994 depressogenic effect Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 208000014674 injury Diseases 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/12—Transmitting gear between valve drive and valve
- F01L1/18—Rocking arms or levers
- F01L1/185—Overhead end-pivot rocking arms
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/20—Adjusting or compensating clearance
- F01L1/22—Adjusting or compensating clearance automatically, e.g. mechanically
- F01L1/24—Adjusting or compensating clearance automatically, e.g. mechanically by fluid means, e.g. hydraulically
- F01L1/2405—Adjusting or compensating clearance automatically, e.g. mechanically by fluid means, e.g. hydraulically by means of a hydraulic adjusting device located between the cylinder head and rocker arm
Definitions
- the present invention relates to a hydraulic valve head clearance eliminating device, that is a so-called hydraulic lash adjustor, in a valve-operating mechanism and more particularly to an improved hydraulic lash adjustor for automatically eliminating valve head clearance in the valve operating mechanism for an internal combustion engine with the aid of resilient force given by a resilient means and hydraulic force so that the valve operating mechanism can be reliably and quietly operated for a long period of time and excellent durability is assured.
- a hydraulic lash adjustor is equipped with a check valve located in the interior thereof so as to open or close a hydraulic passage formed in the adjustor and due to the fact that the check valve moves violently within a valve cage which serves to contain the valve therein there is necessity for firmly holding the valve cage in order to assure that the check valve operates properly at all time.
- Fig. 1 being a vertical sectional view of the whole lash adjustor
- Fig. 2 being a fragmentary vertical sectional view of an important detail of the lash adjustor, shown on an enlarged scale.
- the hydraulic lash adjustor includes a cylinder 1 which serves as a housing therefor.
- the cylinder 1 is designed in the form of a bottomed hollow cylinder which is open at upper end part 1a while having a closed bottom wall 1 at the lower end part thereof and which is fitted into a support hole Ea of an engine casing E.
- a plunger 2 with a semi-spherical top part 2a formed at its upper end is slidably inserted into the cylinder 1 through the open end part 1a a and a hydraulic chamber 3 is defined between the lower end part of the plunger 2 and the bottom wall 1 b of the cylinder 1.
- the plunger 2 is formed with a hydraulic oil reservoir chamber 4 in the interior and has a valve bore 5 at its bottom portion by way of which bore the hydraulic oil reservoir chamber 4 is in communication with the hydraulic chamber 3.
- the hydraulic oil reservoir chamber 4 is in communication with a hydraulic oil supply passage 10 via a through hole 6 on the side wall of the plunger 2, an annular hydraulic passage 7 between both the sliding surfaces of the cylinder 1 and the plunger 2, a through hole 8 on the side wall of the cylinder 1 and an annular hydraulic passage 9 on the outer surface of the cylinder 1 so that the chamber 4 is always filled with hydraulic oil which is delivered through the hydraulic oil supply passage 10.
- the plunger 2 includes a cylindrical portion 11 at its lower end which is adapted to abut against a shoulder 1c formed on the inner side wall of the cylinder 1 at a position located in the proximity of the bottom of the latter so as to define a positional limit of downward movement of the plunger 2.
- valve cage 12 is disposed in the hydraulic chamber 3.
- the valve cage 12 comprises a main body 12a and a flange portion 12b made integral with the ' former and extending radially outward from the upper end of the body 12a.
- a through hole 13 is formed on the side wall of the main body 12a and the outer peripheral part of the flange portion 12b is fitted into an annular engagement groove 14 on the inner side wall of the cylindrical portion 11 of the plunger 2.
- a check valve 15 in the form of a ball is floatably housed in the valve cage 12 so as to open or close the valve bore 5.
- the conventional hydraulic lash adjustor is so constructed that the check valve 15 is caused to open as hydraulic pressure in the hydraulic chamber 3 decreases and close as it increases and a stopper 16 is provided at the bottom of the valve cage 12 so as to confine a working stroke of the check valve 15.
- a resilient spring 17 in the form of a coil spring is contained in the hydraulic chamber 3 to apply thrusting force to the plunger 2 from the bottom side therof.
- the semi-spherical top end part 2a of the plunger 2 abuts against the righthand end part of a rocker arm R as seen in Fig. 1 and the lefthand end part of the latter abuts against the valve head of a poppet valve V which serves to open or close an intake valve or an exhaust valve on the engine casing E, wherein an operating cam C is disposed at a position intermediate between both the righthand and lefthand end parts of the rocker arm R so that the poppet valve V is opened by rotation of the operating cam C.
- the poppet valve V is usually equipped with a valve spring S in the form of a coil spring which is adapted to urge the valve in the closing direction. It should be noted that resilient force of the valve spring S is set far stronger than that of the resilient spring 17 in the hydraulic chamber 3.
- a conventional hydraulic lash adjustor of the above type has the following drawbacks because of the fact that the valve cage 12 with the check valve 15 housed therein is held in place merely by fitting its flange portion 12b into the annular engagement groove 14 on the inner side wall of the cylindrical portion 11 of the plunger 2.
- a prior art device as disclosed in U.S. Patent 3,967,602 also suffers from the above disadvantages because its cup-shaped valve cage having a radial flange is held against axial movement by spring means which merely urges the flange onto the bottom face of the plunger.
- a hydraulic lash adjustor in a valve operating mechanism of the type including a cylinder, a plunger slidably fitted into said cylinder, a hydraulic chamber defined between both the cylinder and the plunger, a hydraulic oil reservoir chamber formed in the plunger, said hydraulic oil reservoir chamber being in communication with the hydraulic chamber by way of a valve bore which is formed in the plunger, a check valve mdunted to said valve bore so as to open when hydraulic pressure in the hydraulic chamber decreases and close when it increases, and a valve cage disposed on the plunger and accommodating therein the check valve, wherein the plunger is so biased by a resilient means asto project outwardly of the cylinder to support at its outermost end a rocker arm of the valve operating mechanism and wherein valve opening force generated by an operating cam of the valve operating mechanism is transmitted to the plunger as a force depressing the plunger in the axial direction, the valve cage comprising a cup-shaped main body and a flange portion integrally extending radially outward
- valve cage with the check valve housed therein is firmly secured to the plunger without any fear of causing dropping of the valve cage and of generating unpleasant noise, while the extent of displacement of the checkvalve is always maintained within a predetermined range so as to ensure proper operation of the checkvalve. Further, theflange portion ofthevalve cage is firmly secured to the plunger irrespective of fluctuated machining errors of holding members for firmly securing the valve cage to the plunger.
- the present hydraulic lash adjustor is constructed such that the valve cage comprises the cup-shaped main body and the flange portion extending radially outward from the peripheral end part of the main body and the flange portion is firmly held between the inner end surface of the plunger and the holding member fitted into the annular engagement groove formed in the plunger, it is assured that the valve cage is firmly secured to the plunger without any fear of causing deformation, damage or injury and of generating unpleasant noise due to abutment or frictional sliding movement of the valve cage with respect to the plunger and moreover the check valve accommodated in the valve cage is reliably and quietly operated for a long period of time while the extent of displacement of the check valve within the valve cage is kept constant at all times.
- the holding member is supported by a retainer fitted into the lower end part of the plunger from the bottom side thereof and the retainer is in turn resiliently supported by the resilient member.
- the holding member can be retained more reliably, thus further enhancing advantageous functional effects.
- the holding member By forming at least a lower side wall surface constituting the annular engagement groove located at the bottom side of the cylinder as a tapered face extending radially inward in such a manner as to cause the open width of the annular engagement groove to enlarge toward the axis of the plunger, as hereinafter described, the holding member can be smoothly fitted into the annular engagement groove by way of expansive displacement of the holding member along the tapered face during the fitting operation until it is located at the predetermined position within the annular engagement groove and therefore the flange portion of the valve cage can be reliably secured to the plunger.
- a plunger 2 has a cylindrical portion 11 at its lower end part and an annular engagement groove 24 is formed around the inner wall surface of the cylindrical portion 11 at a position located away from the inner end surface of the plunger 2 by a distance substantially equal to the thickness of a flange portion 12b of a valve cage 12.
- the outer periphery of the flange portion 12b of the valve cage 12 is fitted into the inner periphery of the cylindrical portion 11 of the plunger 2.
- a caulking ring 30 to serve as a holding member is inserted into the cylindrical portion 11 of the plunger 2 and it is then expanded by operating a caulking punch P so as to cause it to be forcibly fitted into the engagement groove 24 whereby the flange portion 12b of the valve cage 12 is firmly held between the caulking ring 30 and the inner end surface of the plunger 2. Since the caulking ring 30 is subjected to plastic deformation during caulking operation until the flange portion 12b is tightly fitted into the annular engagement groove 24, it results that the valve cage 12 is immovably secured to the plunger 2 without any fear of causing vertical displacement or turning movement which may generate unpleasant noise due to collision or frictional sliding movement of the valve cage 12 with respect to the plunger 2. Accordingly, the distance of displacement of a check valve 15 within the valve cage 12 can be always kept constant.
- a plunger 2 has a cylindrical portion 11 at its lower end part and an annular engagement groove 25 having a female tapered face t 1 is formed around the inner wall surface of the cylindrical portion 11 at a position located away from the inner end surface of the plunger 2 by a distance appreciably less than the thickness of a flange portion 12b of a valve cage 12.
- the outer periphery of the flange portion 12b of the valve cage 12 is fitted into the inner periphery of the cylindrical portion 11 of the plunger 2. Accordingly, no interferential dimension exists between the outer diameter of the flange portion 12b and the inner diameter of the cylindrical portion 11 either in this embodiment.
- a snap ring 31 having a male tapered face t 2 corresponding to the female tapered face t 1 on the annular engagement groove 25 is resiliently fitted into the groove 25.
- the snap ring 31 has a cutout formed at a part thereof and it is so dimensioned to have its outer diameter larger than the inner diameter of the cylindrical portion 11 of the plunger 2 in a freely expanded state.
- the third embodiment provides a special means for preventing a snap ring 32 from dropping out of the annular engagement groove 26 in addition to the arrangement as disclosed in the above-described second embodiment. Specifically, after the snap ring 32 is resiliently fitted into the annular engagement groove 26, a retainer 22 is additionally inserted into the cylindrical portion 11 of the plunger 2 and a coil spring 17 is then disposed below the retainer 22 in such a manner as to resiliently support the retainer 22 from the bottom side thereof.
- Fig. 8 illustrates a hydraulic lash adjustor in accordance with the fourth embodiment of the invention wherein a caulking ring having a specific cross-sectional configuration is employed as a holding member.
- a plunger 2. has a cylindrical portion 11 at its lower end part and an annular engagement groove 27 is formed around the inner wall surface of the cylindrical portion 11 at a position spaced from the inner end surface of the plunger 2 by a distance equal to or appreciably less than the thickness of a flange portion 12b of a valve cage 12.
- the annular engagement groove 27 has its lower side wall surface formed to be a tapered face t 3 inclined downward in the radially inward direction so that its open width increases towards the axis of the plunger.
- fitting of a caulking ring 33 into the groove 27 is precisely carried out by plastic deformation of said caulking ring 33 along the tapered face t 3 at its outside lower edge portion until the caulking ring 33 assumes a predetermined position.
- fitting of the caulking ring 33 into the annular engagement groove 27 can be achieved more smoothly and easily than in case of the first embodiment where the annular engagement groove has its lower side wall surface extending at right angles to the axis of the plunger 2.
- a caulking ring is so designed that its lower surface is located below the lower side wall surface of an annular engagement groove prior to carrying out caulking operation in order to assure that the caulking ring is fitted into the annular engagement groove with an engagement strength higher than certain level, i.e., the outer peripheral surface of the caulking ring partially overlaps the inner wall surface of the cylindrical portion of the plunger immediately below and continuous with the lower side wall surface of the engagement groove.
- the extent of overlapping fluctuates within a certain range due to machining errors of caulking rings to be used.
- the caulking ring 33 can serve as an effective holding member for a long period of time and therefore a valve operating mechanism can work reliably and quietly for a longer period of time. It should also be noted that a larger extent of overlapping is permissible than in the case of the first embodiment.
- an inclination angle of the tapered face t 3 in the annular engagement groove 27 is selectively determined in the range of 15 to 45 degrees with respect to the plane extending at right angles to the axis of the plunger 2, taking into account the direction of application of caulking load when the caulking ring 24 is mounted.
- Figs. 9 to 11 schematically illustrate a hydraulic lash adjustor in accordance with the fifth embodiment of the invention, wherein the structure of the hydraulic lash adjustor is partially modified from that of the fourth embodiment.
- an annular engagement groove 28 has an upper tapered face t 4 in addition to the lower tapered face t 3 which has already been proposed in the foregoing fourth embodiment.
- Both the tapered faces t 3 and t 4 extend radially inward in a diverging manner, that is, in opposite inclined directions to one another with respect to a plane extending at right angles to the axis of the plunger 2.
- the tapered face t 3 extends inward at a downward inclination angle of 8
- the tapered face t 4 extends inward at an upward inclination angle of 0'.
- the inclination angles 6 and 8' of both the tapered faces t 3 and t 4 are selectively determined in the range of 15 to 45 degrees in the same manner as in the case of the foregoing fourth embodiment. They may be enlarged to the maximum of 60 degrees without any loss of advantageous functional features.
- the arrangement made in accordance with this embodiment ensures that there is formed no useless escape area for the caulking ring 34 at the time of fitting of the latter into the annular engagement groove 28 and moreover caulking operation is performed more smoothly and reliably.
- the caulking ring 34 is fitted into the annular engagement groove 28 until its outer peripheral surface comes in close contact with the innermost end wall of the groove 28, there is no fear of causing unexpected displacement of the caulking ring 34 within the annular engagement groove 28 or locating it at any geometrically unstable position.
- the flange portion 12b of the valve cage 12 can be immovably held between the inner end surface of the plunger 2 and the caulking ring 34.
- a lathing bit for machining the annular engagement groove 28 may be designed in such a configuration as to correspond to the cross-sectional confi.guration of the groove 28, i.e., in a trapezoidal configuration with a tapered tip end portion, thereby elongating running life of the lathing bit.
- the caulking ring 34 is plastically deformed smoothly along the lower tapered face t 3 during caulking operation in the same manner as in the case of the fourth embodiment even if the amount of overlapping of the caulking ring 34 with respect to the annular engagement groove 28 is excessively large, and therefore the caulking ring 34 is brought in surface contact with the tapered side face t 3 as illustrated in Fig. 10. As a result, there is no fear of reducing durability of the hydraulic lash adjustor. On the other hand, when the extent of overlapping is small, the caulking ring 34 is necessarily brought in contact with at least part of the tapered face t 3 on the side of the bottom surface of the groove 28 as illustrated in Fig.
- the caulking ring 34 can be reliably fitted into the annular engagement groove 28 by caulking operation irrespective of the amount of overlapping.
- valve cage 12 has a cup-shaped main body 12a.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Valve-Gear Or Valve Arrangements (AREA)
Description
- The present invention relates to a hydraulic valve head clearance eliminating device, that is a so-called hydraulic lash adjustor, in a valve-operating mechanism and more particularly to an improved hydraulic lash adjustor for automatically eliminating valve head clearance in the valve operating mechanism for an internal combustion engine with the aid of resilient force given by a resilient means and hydraulic force so that the valve operating mechanism can be reliably and quietly operated for a long period of time and excellent durability is assured.
- In general, a hydraulic lash adjustor is equipped with a check valve located in the interior thereof so as to open or close a hydraulic passage formed in the adjustor and due to the fact that the check valve moves violently within a valve cage which serves to contain the valve therein there is necessity for firmly holding the valve cage in order to assure that the check valve operates properly at all time.
- To facilitate understanding of the present invention" it will be helpful that a hitherto known hydraulic lash adjustor will be described below with reference to Figs. 1 and 2 of the accompanying drawings, Fig. 1 being a vertical sectional view of the whole lash adjustor and Fig. 2 being a fragmentary vertical sectional view of an important detail of the lash adjustor, shown on an enlarged scale.
- Referring to Figs. 1 and 2, the hydraulic lash adjustor includes a cylinder 1 which serves as a housing therefor. As is apparent from the drawings, the cylinder 1 is designed in the form of a bottomed hollow cylinder which is open at upper end part 1a while having a closed bottom wall 1 at the lower end part thereof and which is fitted into a support hole Ea of an engine casing
E. A plunger 2 with a semi-spherical top part 2a formed at its upper end is slidably inserted into the cylinder 1 through the open end part 1a a and ahydraulic chamber 3 is defined between the lower end part of theplunger 2 and the bottom wall 1 b of the cylinder 1. Further, theplunger 2 is formed with a hydraulicoil reservoir chamber 4 in the interior and has avalve bore 5 at its bottom portion by way of which bore the hydraulicoil reservoir chamber 4 is in communication with thehydraulic chamber 3. The hydraulicoil reservoir chamber 4 is in communication with a hydraulic oil supply passage 10 via a through hole 6 on the side wall of theplunger 2, an annular hydraulic passage 7 between both the sliding surfaces of the cylinder 1 and theplunger 2, a through hole 8 on the side wall of the cylinder 1 and an annular hydraulic passage 9 on the outer surface of the cylinder 1 so that thechamber 4 is always filled with hydraulic oil which is delivered through the hydraulic oil supply passage 10. - The
plunger 2 includes acylindrical portion 11 at its lower end which is adapted to abut against a shoulder 1c formed on the inner side wall of the cylinder 1 at a position located in the proximity of the bottom of the latter so as to define a positional limit of downward movement of theplunger 2. - A
valve cage 12 is disposed in thehydraulic chamber 3. Specifically, thevalve cage 12 comprises amain body 12a and a flange portion 12b made integral with the' former and extending radially outward from the upper end of thebody 12a. A through hole 13 is formed on the side wall of themain body 12a and the outer peripheral part of the flange portion 12b is fitted into anannular engagement groove 14 on the inner side wall of thecylindrical portion 11 of theplunger 2. - A
check valve 15 in the form of a ball is floatably housed in thevalve cage 12 so as to open or close thevalve bore 5. The conventional hydraulic lash adjustor is so constructed that thecheck valve 15 is caused to open as hydraulic pressure in thehydraulic chamber 3 decreases and close as it increases and astopper 16 is provided at the bottom of thevalve cage 12 so as to confine a working stroke of thecheck valve 15. Further, to assure that theplunger 2 projects upward above the upper end of the cylinder 1 aresilient spring 17 in the form of a coil spring is contained in thehydraulic chamber 3 to apply thrusting force to theplunger 2 from the bottom side therof. - The semi-spherical top end part 2a of the
plunger 2 abuts against the righthand end part of a rocker arm R as seen in Fig. 1 and the lefthand end part of the latter abuts against the valve head of a poppet valve V which serves to open or close an intake valve or an exhaust valve on the engine casing E, wherein an operating cam C is disposed at a position intermediate between both the righthand and lefthand end parts of the rocker arm R so that the poppet valve V is opened by rotation of the operating cam C. The poppet valve V is usually equipped with a valve spring S in the form of a coil spring which is adapted to urge the valve in the closing direction. It should be noted that resilient force of the valve spring S is set far stronger than that of theresilient spring 17 in thehydraulic chamber 3. - Next, operation of the conventional hydraulic lash adjustor will be described below.
- While the poppet valve V is kept closed, the
plunger 2 is caused to move upward under the influence of resilient force of theresilient spring 17 until the righthand end part of the rocker arm R is raised up and thereby clearance between the lefthand end part of the rocker arm R and the valve head of the poppet valve V is eliminated. As theplunger 2 is raised up and thereby hydraulic pressure in thehydraulic chamber 3 decreases, thecheck valve 15 is opened and hydraulic oil in the hydraulicoil reservoir chamber 4 flows into thehydraulic chamber 3 via thevalve bore 5 whereby thehydraulic chamber 3 is filled with hydraulic oil again. - Next, when the cam face on the operating cam C comes in contact with the rocker arm R as it is rotated, the rocker arm R is depressed its intermediate part and thereby valve opening force is generated. In response to valve opening force, hydraulic pressure is developed in the
hydraulic chamber 3 which has been kept closed by means of thecheckvalve 15 and it results that theplunger 2 is supported under application of the thus developed hydraulic pressure onto the bottom surface thereof. Thus, the rocker arm R is caused to pivot downwardly toward the poppet valve V about the semi-spherical end part2a of theplunger 2 which serves as a fulcrum, whereby the poppet valve V is opened against resilient force of the valve spring S. During the downward pivoting movement of the rocker arm R, a very small amount of hydraulic oil in thehydraulic chamber 3 leaks through close clearance between the sliding surfaces of the cylinder 1 and theplunger 2 but the leaked amount of hydraulic oil will be compensated by an auxiliary supply from the hydraulicoil reservoir chamber 4 during next closing operation of the poppet valve V. - However, it has been found that a conventional hydraulic lash adjustor of the above type has the following drawbacks because of the fact that the
valve cage 12 with thecheck valve 15 housed therein is held in place merely by fitting its flange portion 12b into theannular engagement groove 14 on the inner side wall of thecylindrical portion 11 of theplunger 2. - (1) There is fear of causing disconnection of the
valve cage 12 from the annular engagement groove 14when a considerably large volume of air enters thehydraulic chamber 3 during operation of an engine at a high speed or oil feeding, because thecheck valve 15 resonates in thevalve cage 12 and a high intensity of impulsive force caused by such resonance is adversely transmitted to thevalve cage 12. - (2) To inhibit disconnection of the
valve cage 12 in that way there has been proposed an arrangement that interferencial dimension is provided for the flange portion 12b of thevalve cage 12 so as to allow it to be forcibly fitted into theannular engagement groove 14. Thevalve cage 12 is generally manufactured by press forming, because a machining operation causes a substantially increased manufacturing cost. To practice the proposal there is necessity for maintaining dimensional tolerance of the flange portion 12b of thevalve cage 12 within a strictly close range but it is difficult to meet this necessity so that interferencial dimension fluctuates. If the interferencial dimension is excessively small, there is fear of causing thevalve cage 12 to drop out of its place in the same manner as in the foregoing. On the contrary, if it is excessively large, plastic deformation tends to take place with the flange portion 12b at the time of fitting into theannular engagement groove 14, resulting in an occurence of fluctuation in clearance for displacement of thecheck valve 15 within thevalve cage 12. Furthermore, there may be a case where it becomes difficult to assure an extent of displacement of thecheck valve 15 required for its intended operation. In another case, there may be produced a cracking in thevalve cage 12, resulting in that thevalve cage 12 becomes liable to drop out of its place in theannular engagement groove 14. - (3) To assure that the flange portion 12b of the
valve cage 12 is reliably fitted into theannular engagement groove 14 it is inevitably necessary to keep an appreciable amount of dimensional clearance between the width of theannular engagement groove 14 and the thickness of the flange portion 12b of thevalve cage 12. However, this in turn causes thevalve cage 12 to move toward and away from theplunger 2 or to rotate in thegroove 14 and moreover unpleasant noise is generated due to abutment or frictional sliding movement of the former with respect to the latter. Thus, it becomes impossible to keep constant the extent of displacement of the check valve. Also in this case there is fear of causing the check valve to drop out in the above-described manner. - A prior art device as disclosed in U.S. Patent 3,967,602 also suffers from the above disadvantages because its cup-shaped valve cage having a radial flange is held against axial movement by spring means which merely urges the flange onto the bottom face of the plunger.
- According to the present invention there is provided a hydraulic lash adjustor in a valve operating mechanism of the type including a cylinder, a plunger slidably fitted into said cylinder, a hydraulic chamber defined between both the cylinder and the plunger, a hydraulic oil reservoir chamber formed in the plunger, said hydraulic oil reservoir chamber being in communication with the hydraulic chamber by way of a valve bore which is formed in the plunger, a check valve mdunted to said valve bore so as to open when hydraulic pressure in the hydraulic chamber decreases and close when it increases, and a valve cage disposed on the plunger and accommodating therein the check valve, wherein the plunger is so biased by a resilient means asto project outwardly of the cylinder to support at its outermost end a rocker arm of the valve operating mechanism and wherein valve opening force generated by an operating cam of the valve operating mechanism is transmitted to the plunger as a force depressing the plunger in the axial direction, the valve cage comprising a cup-shaped main body and a flange portion integrally extending radially outward from the peripheral end part of said main body; characterised in that the flange portion is firmly held in place onto the inner end surface of the plunger by a holding member fitted into an annular engagement groove formed in the plunger. In this hydraulic lash adjustor the valve cage with the check valve housed therein is firmly secured to the plunger without any fear of causing dropping of the valve cage and of generating unpleasant noise, while the extent of displacement of the checkvalve is always maintained within a predetermined range so as to ensure proper operation of the checkvalve. Further, theflange portion ofthevalve cage is firmly secured to the plunger irrespective of fluctuated machining errors of holding members for firmly securing the valve cage to the plunger.
- Since the present hydraulic lash adjustor is constructed such that the valve cage comprises the cup-shaped main body and the flange portion extending radially outward from the peripheral end part of the main body and the flange portion is firmly held between the inner end surface of the plunger and the holding member fitted into the annular engagement groove formed in the plunger, it is assured that the valve cage is firmly secured to the plunger without any fear of causing deformation, damage or injury and of generating unpleasant noise due to abutment or frictional sliding movement of the valve cage with respect to the plunger and moreover the check valve accommodated in the valve cage is reliably and quietly operated for a long period of time while the extent of displacement of the check valve within the valve cage is kept constant at all times.
- As described hereinafter, in a particular form the holding member is supported by a retainer fitted into the lower end part of the plunger from the bottom side thereof and the retainer is in turn resiliently supported by the resilient member. In this construction the holding member can be retained more reliably, thus further enhancing advantageous functional effects.
- By forming at least a lower side wall surface constituting the annular engagement groove located at the bottom side of the cylinder as a tapered face extending radially inward in such a manner as to cause the open width of the annular engagement groove to enlarge toward the axis of the plunger, as hereinafter described, the holding member can be smoothly fitted into the annular engagement groove by way of expansive displacement of the holding member along the tapered face during the fitting operation until it is located at the predetermined position within the annular engagement groove and therefore the flange portion of the valve cage can be reliably secured to the plunger.
- For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made, by way of example, to Figs. 3 to 11 of the accompanying drawings which illustrate several preferred embodiments of the present invention.
- The accompanying drawings will be briefly described below.
- Figs. 1 and 2 illustrate a hitherto known hydraulic lash adjustor, wherein Fig. 1 is a vertical sectional view of the whole lash adjustor and Fig. 2 is a fragmentary vertical sectional view of an essential part of the lash adjustor, shown in an enlarged scale.
- Figs. 3 and 4 illustrate a hydraulic lash adjustor in accordance with a first embodiment of the present invention, wherein Fig. 3 is a fragmentary vertical sectional view of an essential part of the lash adjustor, shown in an enlarged scale and Fig. 4 is a plan view of a caulking ring as seen in the plane taken in line IV-IV of Fig. 3.
- Figs. 5 and 6 illustrate a hydraulic lash adjustor in accordance with a second embodiment of the present invention, wherein Fig. 5 is a fragmentary vertical sectional view of an essential part of the lash adjustor, shown in an enlarged scale and Fig. 6 is a plan view of a snap ring as seen in the plane taken in line VI-VI of Fig. 5.
- Fig. 7 is a fragmentary vertical sectional view of an essential part of a hydraulic lash adjustor in accordance with a third embodiment of the present invention, shown in an enlarged scale.
- Fig. 8 is an enlarged fragmentary vertical sectional view of a hydraulic lash adjustor in accordance with a fourth embodiment of the present invention.
- Figs. 9 to 11 illustrate a hydraulic lash adjustor in accordance with a fifth embodiment of the present invention, wherein Fig. 9 is an enlarged fragmentary vertical sectional view of an essential part of the lash adjustor, while Figs. 10 and 11 are enlarged fragmentary vertical sectional views similar to Fig. 9, respectively, illustrating exemplified fitted states of caulking rings into an annular engagement groove formed on the inner side wall of the cylindrical portion of the plunger.
- Now, the present invention will be described in a greater detail hereunder with reference to Figs. 3 to 11 of the accompanying drawings which illustrate preferred embodiments of the invention. It should be noted that the same parts and components as those in Figs. 1 and 2 are identified. with the same reference characters and numerals.
- First, a hydraulic lash adjustor in accordance with the first embodiment of the invention will be described with reference to Figs. 3 and 4.
- A
plunger 2 has acylindrical portion 11 at its lower end part and an annular engagement groove 24 is formed around the inner wall surface of thecylindrical portion 11 at a position located away from the inner end surface of theplunger 2 by a distance substantially equal to the thickness of a flange portion 12b of avalve cage 12. The outer periphery of the flange portion 12b of thevalve cage 12 is fitted into the inner periphery of thecylindrical portion 11 of theplunger 2. In this embodiment, there is appreciably small dimensional difference between the outer diameter of the flange portion 12b and the inner diameter of thecylindrical portion 11 of theplunger 2 and therefore no interferential dimension exists with respect to thecylindrical portion 11 of theplunger 2. Next, acaulking ring 30 to serve as a holding member is inserted into thecylindrical portion 11 of theplunger 2 and it is then expanded by operating a caulking punch P so as to cause it to be forcibly fitted into the engagement groove 24 whereby the flange portion 12b of thevalve cage 12 is firmly held between thecaulking ring 30 and the inner end surface of theplunger 2. Since thecaulking ring 30 is subjected to plastic deformation during caulking operation until the flange portion 12b is tightly fitted into the annular engagement groove 24, it results that thevalve cage 12 is immovably secured to theplunger 2 without any fear of causing vertical displacement or turning movement which may generate unpleasant noise due to collision or frictional sliding movement of thevalve cage 12 with respect to theplunger 2. Accordingly, the distance of displacement of acheck valve 15 within thevalve cage 12 can be always kept constant. - Next, a hydraulic lash adjustor in accordance with the second embodiment of the invention will be described with reference to Figs. 5 and 6.
- A
plunger 2 has acylindrical portion 11 at its lower end part and an annular engagement groove 25 having a female tapered face t1 is formed around the inner wall surface of thecylindrical portion 11 at a position located away from the inner end surface of theplunger 2 by a distance appreciably less than the thickness of a flange portion 12b of avalve cage 12. The outer periphery of the flange portion 12b of thevalve cage 12 is fitted into the inner periphery of thecylindrical portion 11 of theplunger 2. Accordingly, no interferential dimension exists between the outer diameter of the flange portion 12b and the inner diameter of thecylindrical portion 11 either in this embodiment. - Next, a
snap ring 31 having a male tapered face t2 corresponding to the female tapered face t1 on the annular engagement groove 25 is resiliently fitted into the groove 25. As is apparent from Fig. 6, thesnap ring 31 has a cutout formed at a part thereof and it is so dimensioned to have its outer diameter larger than the inner diameter of thecylindrical portion 11 of theplunger 2 in a freely expanded state. When it is resiliently fitted into the annular engagement groove 25, clearance between the flange portion 12b and thesnap ring 31 disappears due to tight engagement of the male tapered face t2 to the female tapered face t1 whereby the flange portion 12b of thevalve cage 12 is immovably held between the inner end surface of theplunger 2 and thesnap ring 31 without causing vertical displacement or turning movement of thevalve cage 12. If acoil spring 17 is so arranged to provide only a small clearance between itself and thesnap ring 31, thesnap ring 31 can be prevented from dropping out of the annular engagement groove 25 by abutment against thespring 17. - Next, a hydraulic lash adjustor in accordance with the third embodiment of the invention will be described with reference to Fig. 7.
- The third embodiment provides a special means for preventing a snap ring 32 from dropping out of the annular engagement groove 26 in addition to the arrangement as disclosed in the above-described second embodiment. Specifically, after the snap ring 32 is resiliently fitted into the annular engagement groove 26, a
retainer 22 is additionally inserted into thecylindrical portion 11 of theplunger 2 and acoil spring 17 is then disposed below theretainer 22 in such a manner as to resiliently support theretainer 22 from the bottom side thereof. - Next, Fig. 8 illustrates a hydraulic lash adjustor in accordance with the fourth embodiment of the invention wherein a caulking ring having a specific cross-sectional configuration is employed as a holding member. As is apparent from the drawing, a
plunger 2. has acylindrical portion 11 at its lower end part and anannular engagement groove 27 is formed around the inner wall surface of thecylindrical portion 11 at a position spaced from the inner end surface of theplunger 2 by a distance equal to or appreciably less than the thickness of a flange portion 12b of avalve cage 12. Theannular engagement groove 27 has its lower side wall surface formed to be a tapered face t3 inclined downward in the radially inward direction so that its open width increases towards the axis of the plunger. Owing to the cross-sectional configuration of theannular engagement groove 27 as described above, fitting of a caulking ring 33 into thegroove 27 is precisely carried out by plastic deformation of said caulking ring 33 along the tapered face t3 at its outside lower edge portion until the caulking ring 33 assumes a predetermined position. Thus, fitting of the caulking ring 33 into theannular engagement groove 27 can be achieved more smoothly and easily than in case of the first embodiment where the annular engagement groove has its lower side wall surface extending at right angles to the axis of theplunger 2. Generally, a caulking ring is so designed that its lower surface is located below the lower side wall surface of an annular engagement groove prior to carrying out caulking operation in order to assure that the caulking ring is fitted into the annular engagement groove with an engagement strength higher than certain level, i.e., the outer peripheral surface of the caulking ring partially overlaps the inner wall surface of the cylindrical portion of the plunger immediately below and continuous with the lower side wall surface of the engagement groove. However, the extent of overlapping fluctuates within a certain range due to machining errors of caulking rings to be used. Assuming here that the amount of overlapping is large and a caulking load is insufficiently applied to thecaulking ring 30 of the first embodiment where the lower side wall surface of the annular engagement groove 24 extends inward at right angles to the axis of theplunger 2, it is expected that irregular plastic deformation may take place, for example, a part of thecaulking ring 30 may be cut away by the corner edge of the annular engagement groove 24 and/or stress concentration may appear at contact areas of thecaulking ring 30 brought in point contact or line contact with bottom and side wall surfaces of the annular engagement groove. However, such fear as described above never arise in a case where the lower side wall surface is inclined in the form of a tapered face as in the fourth embodiment. Accordingly, the caulking ring 33 can serve as an effective holding member for a long period of time and therefore a valve operating mechanism can work reliably and quietly for a longer period of time. It should also be noted that a larger extent of overlapping is permissible than in the case of the first embodiment. - Incidentally, an inclination angle of the tapered face t3 in the
annular engagement groove 27 is selectively determined in the range of 15 to 45 degrees with respect to the plane extending at right angles to the axis of theplunger 2, taking into account the direction of application of caulking load when the caulking ring 24 is mounted. - Next, Figs. 9 to 11 schematically illustrate a hydraulic lash adjustor in accordance with the fifth embodiment of the invention, wherein the structure of the hydraulic lash adjustor is partially modified from that of the fourth embodiment. Specifically, in this embodiment, an
annular engagement groove 28 has an upper tapered face t4 in addition to the lower tapered face t3 which has already been proposed in the foregoing fourth embodiment. Both the tapered faces t3 and t4 extend radially inward in a diverging manner, that is, in opposite inclined directions to one another with respect to a plane extending at right angles to the axis of theplunger 2. In other words, the tapered face t3 extends inward at a downward inclination angle of 8, whereas the tapered face t4 extends inward at an upward inclination angle of 0'. The inclination angles 6 and 8' of both the tapered faces t3 and t4 are selectively determined in the range of 15 to 45 degrees in the same manner as in the case of the foregoing fourth embodiment. They may be enlarged to the maximum of 60 degrees without any loss of advantageous functional features. Thus, the arrangement made in accordance with this embodiment ensures that there is formed no useless escape area for the caulking ring 34 at the time of fitting of the latter into theannular engagement groove 28 and moreover caulking operation is performed more smoothly and reliably. Further, since the caulking ring 34 is fitted into theannular engagement groove 28 until its outer peripheral surface comes in close contact with the innermost end wall of thegroove 28, there is no fear of causing unexpected displacement of the caulking ring 34 within theannular engagement groove 28 or locating it at any geometrically unstable position. As a result, the flange portion 12b of thevalve cage 12 can be immovably held between the inner end surface of theplunger 2 and the caulking ring 34. - Another advantageous feature of this embodiment is that a lathing bit for machining the
annular engagement groove 28 may be designed in such a configuration as to correspond to the cross-sectional confi.guration of thegroove 28, i.e., in a trapezoidal configuration with a tapered tip end portion, thereby elongating running life of the lathing bit. - Further, also in this embodiment, the caulking ring 34 is plastically deformed smoothly along the lower tapered face t3 during caulking operation in the same manner as in the case of the fourth embodiment even if the amount of overlapping of the caulking ring 34 with respect to the
annular engagement groove 28 is excessively large, and therefore the caulking ring 34 is brought in surface contact with the tapered side face t3 as illustrated in Fig. 10. As a result, there is no fear of reducing durability of the hydraulic lash adjustor. On the other hand, when the extent of overlapping is small, the caulking ring 34 is necessarily brought in contact with at least part of the tapered face t3 on the side of the bottom surface of thegroove 28 as illustrated in Fig. 11 and therefore downward displacement of the caulking ring 34 is reliably inhibited. Thus, the flange portion 12b of thevalve cage 12 can be held firmly in place. As will be apparent from the foregoing, the caulking ring 34 can be reliably fitted into theannular engagement groove 28 by caulking operation irrespective of the amount of overlapping. - It will be noted that in all the embodiments of the invention described the
valve cage 12 has a cup-shapedmain body 12a.
Claims (11)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP133375/82 | 1982-07-30 | ||
JP57133375A JPS5923011A (en) | 1982-07-30 | 1982-07-30 | Oil pressure type valve head gap removing device in valve moving mechanism |
JP57148106A JPS5937220A (en) | 1982-08-26 | 1982-08-26 | Hydraulic lash adjuster |
JP148106/82 | 1982-08-26 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0100241A2 EP0100241A2 (en) | 1984-02-08 |
EP0100241A3 EP0100241A3 (en) | 1985-02-06 |
EP0100241B1 true EP0100241B1 (en) | 1987-05-06 |
Family
ID=26467752
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19830304368 Expired EP0100241B1 (en) | 1982-07-30 | 1983-07-28 | Hydraulic lash adjustor in a valve operating mechanism |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0100241B1 (en) |
DE (1) | DE3371384D1 (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2209574B (en) * | 1983-11-04 | 1990-01-17 | Honda Motor Co Ltd | Lash adjuster |
DE3635110A1 (en) * | 1985-10-15 | 1987-04-16 | Honda Motor Co Ltd | VALVE CONTROL DEVICE FOR AN INTERNAL COMBUSTION ENGINE |
DE19601045A1 (en) * | 1996-01-13 | 1997-07-17 | Schaeffler Waelzlager Kg | Preassembled valve unit for self-adjusting hydraulic tappet |
DE19710577B4 (en) * | 1997-03-14 | 2015-02-12 | Schaeffler Technologies Gmbh & Co. Kg | Hydraulic clearance compensation element |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR333662A (en) * | 1903-07-08 | 1903-12-01 | Charles Comiot | Assembly method of two parts intended to rotate concentrically together |
US2694388A (en) * | 1950-12-30 | 1954-11-16 | Thompson Prod Inc | Self-contained hydraulic valve train length adjusting mechanism |
US2700965A (en) * | 1951-09-20 | 1955-02-01 | Johnson Products Inc | Hydraulic tappet |
US3358660A (en) * | 1967-04-27 | 1967-12-19 | Johnson Products Inc | Pull-out retainer for hydraulic lash adjuster |
NL6918654A (en) * | 1969-12-12 | 1971-06-15 | ||
US3967602A (en) * | 1974-06-10 | 1976-07-06 | Brown William G | Hydraulic valve lifter for reciprocating internal combustion engines |
-
1983
- 1983-07-28 DE DE8383304368T patent/DE3371384D1/en not_active Expired
- 1983-07-28 EP EP19830304368 patent/EP0100241B1/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
DE3371384D1 (en) | 1987-06-11 |
EP0100241A3 (en) | 1985-02-06 |
EP0100241A2 (en) | 1984-02-08 |
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