JP4490310B2 - Rush adjuster - Google Patents

Description

  The present invention relates to a lash adjuster for adjusting a gap between components in a valve gear for an internal combustion engine.

  For example, in an internal combustion engine, the engine body becomes hot due to combustion in the combustion chamber, and the heat is transmitted to the valve mechanism so that the valve mechanism also becomes hot. In order to prevent this, a lash adjuster that adjusts the gaps between the components of the valve operating mechanism is provided. This lash adjuster is interposed between components that are displaced during the operation of the valve mechanism, and prevents the formation of gaps following the change in the distance between them. Wear during operation can be reduced.

  As a conventional lash adjuster applied to an internal combustion engine, for example, there is one described in Patent Document 1 below. In the hydraulic lash adjuster described in Patent Document 1, a plunger body and a reservoir cap are slidably disposed in a cylinder, and a plunger is slidably accommodated in the plunger body to form a hydraulic chamber. In addition, a reservoir chamber opened upward is provided in the plunger, and a check ball is provided in a communication path that connects the reservoir chamber and the hydraulic chamber.

  Therefore, when the reservoir cap is pressed by the cam mechanism, the plunger is pressed by this pressing force, the pressure in the hydraulic chamber is increased, the communication path is closed by the check ball, and the plunger body is lowered together with the plunger to open the valve. Set the valve state. When the operation of pushing the reservoir cap by the cam disappears, the valve starts to rise while the pressure in the hydraulic chamber is maintained. When the valve is closed, the plunger moves by the spring to eliminate the valve clearance, and at the same time, the communication path is opened. As a result, hydraulic oil flows from the reservoir chamber to the high pressure chamber and enters a standby state.

JP 2000-161026 A

  In the above-mentioned Patent Document 1, the plunger body and the reservoir cap are slidably supported in the cylinder, and the plunger body and the reservoir cap are moved downward by the pressing force of the cam mechanism to open the valve, while the valve spring The plunger body and the reservoir cap are moved upward by this urging force to close the valve. In this case, since the plunger body and the reservoir cap slide with respect to the inner peripheral surface of the cylinder, a sliding resistance is generated here. Then, there is a problem that the driving force of the cam mechanism and the urging force of the valve spring are not properly transmitted to the valve, and the valve cannot be opened and closed with high accuracy, so that combustion deteriorates and fuel consumption deteriorates.

  In particular, in an electromagnetically driven valve that electrically opens and closes the valve, the driving energy of the electromagnetic actuator increases due to the sliding resistance between the cylinder and the plunger body and the reservoir cap, which causes a great deterioration in fuel consumption. End up. That is, in an electromagnetically driven valve that does not use a cam mechanism, the friction of the sliding portion attenuates this resonance on the principle of operating by utilizing the resonance of the upper and lower springs, which may lead to an operation error or inoperability. . Therefore, if an excessive current is supplied to the electromagnetic coil to ensure a large driving force, the power consumption increases and the fuel consumption is deteriorated.

  In a general lash adjuster, the oil supplied to the reservoir chamber and the hydraulic chamber leaks to the outside due to the clearance of each constituent member, and circulates through the constituent members of the valve mechanism. However, in the hydraulic lash adjuster of Patent Document 1 described above, a large sliding resistance is generated between the cylinder and the plunger body. Therefore, the oil in the lash adjuster slides the valve from the clearance between the cylinder and the plunger body. There is a risk of insufficient lubrication and insufficient lubrication.

  As described above, in the hydraulic lash adjuster disclosed in Patent Document 1, there is a possibility that the operation failure of the entire valve mechanism is caused by an increase in friction between the cylinder, the plunger body, and the reservoir cap.

  The present invention is intended to solve such problems, and an object thereof is to provide a lash adjuster that improves the operability of the valve operating mechanism.

In order to solve the above-described problems and achieve the object, a lash adjuster according to the present invention includes a reservoir cap that is slidably supported in the cylinder along the axial direction, and a valve mechanism acts on one end, and a cylinder. A plunger body that is slidably supported along the axial direction and has a valve element at one end and a recess that opens toward the reservoir cap at the other end, and is slidably received in the recess. And a plunger that forms a hydraulic chamber with the plunger body, a spring that urges the plunger in a direction to contact the reservoir cap, and a supply oil passage that supplies hydraulic oil to the hydraulic chamber. In the lash adjuster, the sliding clearance between the cylinder and the plunger body is determined by the sliding clearance between the cylinder and the reservoir cap. It is characterized in that it has heard set.

  The lash adjuster according to the present invention is characterized in that a depression is provided on the outer peripheral surface of the plunger body over a region shorter than the axial length.

According to the lash adjuster of the present invention, the reservoir cap on which the valve operating mechanism acts on one end is supported slidably along the axial direction in the cylinder, the valve element acts on one end, and the other end A plunger body having a recess opening toward the reservoir cap is slidably supported in the cylinder along the axial direction, and the plunger is slidably received in the recess to form a hydraulic chamber between the plunger body. The plunger is urged by a spring in a direction to abut against the reservoir cap, and a supply oil passage for supplying hydraulic oil to the hydraulic chamber is provided, and the sliding clearance between the cylinder and the plunger body is determined between the cylinder and the reservoir cap. The plunger body and reservoir cap are set in the cylinder due to the difference in sliding clearance. Becomes the sliding resistance between the surface and the plunger body is reduced, properly lubricating oil is supplied to the valve operating mechanism, it is possible to improve the operability of the valve operating mechanism.

  Embodiments of a lash adjuster according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  1 is a cross-sectional view of a lash adjuster according to a first embodiment of the present invention, and FIG. 2 is a schematic view for explaining sliding clearances between a cylinder, a plunger body, and a reservoir cap in the lash adjuster of the first embodiment. FIGS. 3-1 to 3-3 are schematic views showing a support structure of the armature shaft in the electromagnetically driven valve of the first embodiment, FIG. 4 is a graph showing the friction reduction effect by the lash adjuster of the first embodiment, and FIG. It is sectional drawing showing the electromagnetically driven valve to which the lash adjuster of Example 1 was applied.

  In the electromagnetically driven valve to which the lash adjuster of the present embodiment is applied, as shown in FIG. 5, the electromagnetically driven valve 11 has a valve body 12, which is an intake valve or exhaust of an internal combustion engine. It is configured as a valve. The valve body 12 is disposed in the lower head 14 so as to be exposed in the combustion chamber 13 of the internal combustion engine. A port 15 is formed in the lower head 14, and the opening to the combustion chamber 13 is connected to the valve body 12. A valve seat 16 is formed. The port 15 is opened when the valve body 12 is separated from the valve seat 16, and is closed when the valve body 12 is seated on the valve seat 16.

  A cylinder head spacer 18 is disposed above the lower head 14 via a heat insulating plate 17. The heat insulating plate 17 is a sheet-like member made of a heat insulating material such as bakelite, for example, and has a combustion chamber. 13 has a function of suppressing high heat generated at 13 from being transmitted from the lower head 14 to the cylinder head spacer 18. An upper head 19 is fixed to the upper part of the cylinder head spacer 18.

  The valve body 12 has a valve shaft 20 extending upward. The valve shaft 20 is held by a valve guide 21 fixed to the lower head 14 so as to be slidable in the axial direction. A spring holding space 22 formed in a cylindrical shape is provided at a portion surrounding the upper half of the valve shaft 20 of the lower head 14, and the upper end portion of the valve guide 21 is exposed inside the spring holding space 22. . A valve stem seal 23 is mounted around the upper end of the valve guide 21 in the spring holding space 22.

  A cotter 24 is mounted in the vicinity of the upper end of the valve shaft 20 of the valve body 12, and the cotter 24 has a wedge-shaped outer peripheral surface having a larger diameter toward the upper side, and an inwardly facing inner peripheral surface. It is a substantially cylindrical member provided with protrusions. The protrusion on the inner peripheral surface of the cotter 24 is fitted in a recess provided on the outer peripheral surface of the valve shaft 20. A lower retainer 25 is fitted on the outer periphery of the cotter 24.

  A spring seat 26 is disposed on the bottom surface of the spring holding space 22, and a lower spring 27 is disposed between the spring seat 26 and the lower retainer 25 to generate a biasing force in a direction to separate them. Yes. The lower spring 27 urges the valve body 12 upward via the lower retainer 25, that is, in a direction toward the valve seat 16.

  Above the valve shaft 20 of the valve body 12, an armature shaft 29 is disposed coaxially with the valve shaft 20 via a zero lash adjuster (hereinafter referred to as lash adjuster) 28. The configuration of the lash adjuster 28 will be described in detail later. A cotter 30 having a vertically symmetrical configuration with the cotter 24 is mounted on the upper end portion of the armature shaft 29, and an applicator 31 is fitted around the cotter 30. A lower end portion of the upper spring 32 is in contact with the upper surface of the upper retainer 31, and a cylindrical upper case 33 is disposed around the upper spring 32. Bolts 34 are screwed. Further, the upper end portion of the upper spring 32 is in contact with an adjuster bolt 34 via a spring guide 36, and the upper spring 32 urges the armature shaft 29 downward via the upper retainer 31.

  An armature 37 is joined to the outer periphery of the central portion in the axial direction of the armature shaft 29. The armature 37 is a disk-shaped member made of a soft magnetic material. An upper coil 38 and an upper core 39 are disposed above the armature 37. A lower coil 40 and a lower core 41 are disposed below the armature 37. The upper coil 38 and the lower coil 40 are accommodated in annular grooves formed in the upper core 39 and the lower core 41, respectively.

  The upper core 39 and the lower core 41 have through-holes 39a and 41a penetrating through the center portions thereof, and an upper bush 42 is disposed at the upper end of the through-hole 39a of the upper core 39. A lower bush 43 is disposed at the lower end. The armature shaft 29 is held by an upper bush 42 and a lower bush 43 so as to be slidable in the axial direction.

  The cylinder head spacer 18 is formed with a cylindrical lash adjuster holding space 18 a passing through the upper and lower sides thereof and coaxial with the spring holding space 22. The lash adjuster 28 described above is held in the lash adjuster holding space 18a.

  The upper head 19 is formed with a cylindrical core holding space 19 a penetrating the upper head 19 in the same direction as the spring holding space 22 and the lash adjuster holding space 18 a. The upper core 39 is inserted into the core holding space 19a so that the enlarged flange portion contacts the upper head 19 via the shim 44, and the lower core 41 is inserted so that the expanded flange portion contacts the upper head 19. The upper case 33 and the lower bracket 45 are fixed to the upper head 19 by the fixing bolts 46 and 47, so that the upper core 39 and the lower core 41 are fixed at a predetermined interval.

  The cylinder head spacer 18 is provided with oil supply passages 48 and 49 communicating with each other. Oil is supplied to the oil supply passage 48 from a hydraulic pump (not shown), and the oil supply passage 49 opens at a predetermined position in the lash adjuster holding space 18a.

  In the electromagnetically driven valve 11 configured as described above, when an excitation current is supplied to the upper coil 38, an electromagnetic force in a direction toward the upper core 39 acts on the armature 37 by the magnetic flux generated by the upper coil 38. For this reason, the armature 37 is displaced until it abuts against the upper core 39 against the urging force of the upper spring 32. Hereinafter, the position where the armature 37 contacts the upper core 39 is referred to as a fully closed position of the armature 37, the armature shaft 29, and the valve body 12. In this fully closed state, the valve body 12 is seated on the valve seat 16 so that the valve body 16 is seated. 12 becomes a valve closing state.

  Here, when the supply of the excitation current to the upper coil 38 is stopped in the state where the valve body 12 is closed in this way, the electromagnetic force necessary to hold the armature 37 in the fully closed position disappears. For this reason, when the supply of the excitation current to the upper coil 38 is stopped, the armature shaft 29 starts to be displaced downward by being urged by the upper spring 32 together with the valve body 12. For this reason, the valve body 12 is opened by separating the valve body 12 from the valve seat 16. When an excitation current is supplied to the lower coil 40 when the amount of displacement of the armature shaft 29 reaches a predetermined value, an electromagnetic force that urges the armature 37 toward the lower core 41 is generated.

  When this electromagnetic force acts on the armature 37, the armature 37 is displaced until it abuts against the lower core 41 against the urging force generated by the lower spring 27, and the amount of displacement of the valve body 12 in the valve opening direction is maximized. . Hereinafter, the position where the armature 37 contacts the lower core 41 is referred to as the fully opened position of the armature 37, the armature shaft 29, and the valve body 12. When the supply of the excitation current to the lower coil 40 is stopped in this fully opened state, the armature The electromagnetic force required to hold 37 in the fully open position disappears. For this reason, the valve body 12 and the armature shaft 29 start to be displaced upward by the urging force generated by the lower spring 27. When an excitation current is supplied to the upper coil 38 when these displacement amounts reach predetermined values, the armature 37 is displaced toward the upper core 39 by the electromagnetic force generated by the upper coil 38 until it contacts the upper core 39. In a state where the armature 37 is in contact with the upper core 39, the valve body 12 is again closed by the seating of the valve body 12 on the valve seat 16.

  As described above, in the electromagnetically driven valve 11 of this embodiment, the valve body 12 is repeated between the fully closed position and the fully open position by alternately supplying excitation current to the upper coil 38 and the lower coil 40 at appropriate timing. It can be reciprocated.

  Here, the lash adjuster 28 applied to the electromagnetically driven valve 11 will be described in detail.

  In the lash adjuster 28 according to the first embodiment, as shown in FIG. 1, a plunger body 51 is slidably disposed in a cylinder head spacer (hereinafter referred to as a cylinder) 18. It is a closed substantially cylindrical member. The plunger body 51 is provided therein with a spring accommodating portion 51a provided at the lower end portion and a plunger accommodating portion 51b formed larger in diameter than the spring accommodating portion 51a.

  A plunger 52 is slidably disposed in the plunger accommodating portion 51b of the plunger body 51, and a hydraulic chamber 53 is formed between the lower bottom surface of the plunger 52 and the lower bottom surface of the spring accommodating portion 51a. Has been. The plunger 52 has a large-diameter portion 52a that slides with respect to the inner peripheral surface of the plunger housing portion 51b and a small-diameter portion 52b provided at the upper end portion on the outer peripheral surface. On the other hand, a stopper ring 54 is press-fitted into the upper end of the inner peripheral surface of the plunger accommodating portion 51b, and this stopper ring 54 has a smaller inner diameter than the outer diameter of the large diameter portion 52a. Therefore, the upward displacement of the plunger 52 inside the plunger accommodating portion 51b is restricted by the step between the large diameter portion 52a and the small diameter portion 52b coming into contact with the stopper ring 54. The plunger 52 has a reservoir chamber 55 that opens upward, and a communication passage 56 that connects the reservoir chamber 55 and the hydraulic chamber 53.

  A retainer 57 and a plunger spring 58 are disposed in the hydraulic chamber 53. The plunger spring 58 urges the plunger 52 upward via the retainer 57. A check ball 59 and a check ball spring 60 are disposed inside the retainer 57. The check ball spring 60 urges the check ball 59 toward the opening of the communication path 56. The check ball 59 and the check ball spring 60 function as a check valve that opens only when the hydraulic chamber 53 side has a lower pressure than the reservoir chamber 55 side.

  In addition, a reservoir cap 61 is slidably disposed in the cylinder 18, and the reservoir cap 61 is a cylindrical member having a closed lower end. The reservoir cap 61 is slidable in the cylinder 18 so that the bottom surface thereof is in contact with the upper end surface of the plunger 52. An overflow recess 62, which is partially cut away, is provided on the lower bottom surface of the reservoir cap 61, and the overflow recess 62 is always in communication with the reservoir chamber 55.

  The cylinder 18 is provided with oil supply passages 48 and 49. The oil supply passages 48 and 49 are connected to the overflow recess 62 and the plunger body 51, the plunger 52, and the reservoir cap 61 in the fully closed position. It opens to the inner peripheral surface of the cylinder 18 so as to communicate with each other. Oil of a predetermined pressure is supplied to the oil supply passages 48 and 49 by a hydraulic pump. In addition, when the lash adjuster 28 is assembled, the reservoir chamber 55 and the hydraulic chamber 53 are filled with hydraulic oil.

Further, in the lash adjuster 28 of the present embodiment, as shown in FIGS. 1 and 2, the relationship among the inner diameter D1 of the cylinder 18, the outer diameter d1 of the reservoir cap 61, and the outer diameter d2 of the plunger body 51 is as follows. The relationship is shown in
D1>d1> d2

That is, in this embodiment,
D1-d1 = 0.028mm
D1-d2 = 0.058mm
The sliding clearance (0.058 mm) between the cylinder 18 and the plunger body 51 is set to be larger than the sliding clearance (0.028 mm) between the cylinder 18 and the reservoir cap 61.

Accordingly, oil leaking from the reservoir chamber 55 of the lash adjuster 28 or the like hardly flows upward through the sliding clearance between the cylinder 18 and the reservoir cap 61, and passes through the sliding clearance between the cylinder 18 and the plunger body 51. It tends to flow downward. Therefore, almost no hydraulic oil is supplied to the armature 37, the coils 38, 40, the cores 39, 41, etc. positioned above the lash adjuster 28, and electromagnetic failure due to the hydraulic oil can be prevented. Meanwhile, Rush Adjuster 2
The hydraulic oil is sufficiently supplied to the valve body 12, the valve guide 21, and the like located below 8, and the shortage of lubricating oil can be prevented by this hydraulic oil.

  Further, the plunger body 51 is provided with a recess 51c on the outer peripheral surface thereof. The recess 51c is formed on the outer peripheral surface of the plunger body 51 over the entire circumference over a region A1 shorter than the axial length L. In this case, the region A1 of the recess 51c is located in the axial middle portion of the outer peripheral surface of the plunger body 51, and above and below the sliding regions A2 and A3 sliding with the inner peripheral surface of the cylinder 18. Is provided.

  In this embodiment, as shown in FIG. 3A, the armature shaft 29 in the electromagnetically driven valve 11 is similarly provided with recesses 29 a and 29 b on the outer peripheral surface facing the bushes 42 and 43. . That is, a recess 29a is formed on the outer peripheral surface of the armature shaft 29 facing the upper bush 42 at the neutral position where the coils 38 and 40 are not excited. In addition, a recess 29 b is formed on the entire outer peripheral surface of the armature shaft 29 facing the lower bush 43. In this case, between the upper bush 42 and the armature shaft 29 in order to prevent the supply of hydraulic oil from above to the armature 37, the coils 38, 40, the cores 39, 41, etc. provided in the intermediate portion of the armature shaft 29. It is desirable to set a small clearance. In addition, the clearance between the lower bush 43 and the armature shaft 29 is increased in order to facilitate the discharge of hydraulic oil that has entered the armature 37, the coils 38 and 40, the cores 39 and 41, etc. provided in the intermediate portion of the armature shaft 29. It is desirable to set.

  In the lash adjuster 28 of the present embodiment configured as described above, a downward driving force is applied to the reservoir cap 61 by the armature shaft 29 as shown in FIGS. Further, the valve body 12 of the internal combustion engine is in contact with the lower end surface of the plunger body 51, and the valve body 12 is urged by the lower spring 27 in the valve closing direction, that is, toward the plunger body 51. .

  First, when an exciting current is supplied to the lower coil 40 and an electromagnetic force that urges the armature 37 toward the lower core 41 is generated, the armature 37 is displaced until it abuts against the lower core 41 against the urging force of the lower spring 27. The armature shaft 29 integrated with the armature 37 moves downward to apply a downward driving force to the reservoir cap 61. Then, this driving force is transmitted to the plunger 52. When the driving force transmitted to the plunger 52 exceeds the urging force of the plunger spring 58, the plunger 52 is pressed downward, so that the hydraulic oil in the hydraulic chamber 53 is pressed. Is pressurized. Therefore, the hydraulic pressure in the hydraulic chamber 53 becomes higher than the hydraulic pressure in the reservoir chamber 55, and the communication path 56 is closed by the check ball 59.

  When the communication path 56 is closed, the exchange of hydraulic oil between the hydraulic chamber 53 and the reservoir chamber 55 is prohibited. Therefore, the driving force transmitted to the plunger 52 is transmitted to the plunger body 51 via the hydraulic chamber 53, and the reservoir cap 61, the plunger 52, and the plunger body 51 are integrated and receive the reaction force of the lower spring 27. The valve body 12 is opened by being displaced downward. In the process of opening the valve body 12, the oil in the hydraulic chamber 53 is pressurized, so that the hydraulic oil gradually leaks from the hydraulic chamber 53 via the sliding surface between the plunger 52 and the plunger body 51, and the reservoir The cap 61 presses the plunger 52 and the stroke to the plunger body 51 gradually contracts.

  When the downward displacement of the reservoir cap 61, the plunger 52, and the plunger body 51 reaches the lowest point, the supply of the excitation current to the lower coil 40 is stopped, and the excitation current is supplied to the upper coil 38. Then, the armature 37 is displaced upward toward the upper core 39 by the electromagnetic force generated by the upper coil 38 until it contacts the upper core 39. When the valve body 12 reaches the fully closed position, the reaction force from the lower spring 27 does not act on the plunger body 51. Then, even after the valve body 12 reaches the fully closed position, the reservoir cap 61 continues to be displaced relatively gently upward together with the armature shaft 29. In this case, the plunger 52 follows the reservoir cap 61 by the urging force of the plunger spring 58 and tries to slide upward with respect to the plunger body 51, and the hydraulic pressure in the hydraulic chamber 53 decreases. When the hydraulic chamber 53 has a lower pressure than the reservoir chamber 55, the check ball 59 is separated from the opening of the communication path 56, so that the hydraulic chamber 53 and the reservoir chamber 55 communicate with each other.

  When the valve body 12 is in the fully closed position, the oil supply passage 49 and the overflow recess 62 communicate with each other, so that the hydraulic chamber 53 and the reservoir chamber 55 communicate with each other. By supplying the hydraulic oil to the chamber 53, the plunger 52 slides upward while maintaining the state in contact with the reservoir cap 61.

  When such a lash adjuster 28 is operated, the depression 51 c is provided on the outer peripheral surface of the plunger body 51, so that the sliding resistance between the inner peripheral surface of the cylinder 18 and the outer peripheral surface of the plunger body 51 is reduced. As a result, the plunger body 51 can be smoothly operated, and the operability of the valve body 12 is improved. Further, since the sliding clearance between the cylinder 18 and the plunger body 51 is set to be larger than the sliding clearance between the cylinder 18 and the reservoir cap 61, it is located above the lash adjuster 28 and dislikes the supply of hydraulic oil. The hydraulic oil is prevented from being supplied to the armature 37, the coils 38 and 40, and the cores 39 and 41, while the hydraulic oil is disposed below the lash adjuster 28 and needs to be supplied to the valve body 12 and the valve guide 21. Is sufficiently supplied to prevent a shortage of lubricating oil.

  Further, when the electromagnetically driven valve 11 is operated, the armature shaft 29 reciprocates between the fully open position and the fully closed position as shown in FIGS. 3-2 and 3-3. In this case, since the armature shaft 29 is provided with depressions 29 a and 29 b on the outer peripheral surface facing the bushes 42 and 43, there is a gap between the inner peripheral surface of the bushes 42 and 43 and the outer peripheral surface of the armature shaft 29. The sliding resistance is reduced, the armature shaft 29 can be smoothly operated, and the operability of the valve body 12 is improved. Further, since the clearance between the lower bush 43 and the armature shaft 29 is set larger than the clearance between the upper bush 42 and the armature shaft 29, the armature 37, the coils 38 and 40, the cores 39 and 41, etc. While the supply of the hydraulic oil from above is blocked, the hydraulic oil that has entered the interior is easily discharged downward.

  As described above, in the lash adjuster 28 of the present embodiment, even when the interval between the reservoir cap 61 and the plunger body 51 is changed, the plunger 52 is moved to the plunger body 51 when the valve body 12 reaches the fully closed position. , The plunger 52 and the reservoir cap 61 are kept in contact with each other, and even when the valve body 12 is thermally expanded or worn, the occurrence of a gap is prevented. be able to.

  That is, as shown in FIG. 4, when the friction of the conventional lash adjuster without the recess 51c is set to 100, the friction can be reduced to 60 or less in the lash adjuster 28 of the present embodiment.

  As described above, in the lash adjuster 28 of the first embodiment, the reservoir cap 61 on which the armature shaft 29 acts on the upper end portion is slidably supported in the cylinder 18 and the plunger on which the valve body 12 acts on the lower end portion. The body 51 is slidably supported in the cylinder 18, and the plunger 52 is slidably accommodated in the plunger accommodating portion 51b so as to be biased toward the reservoir cap 61, thereby forming a hydraulic chamber 53 and a reservoir chamber 55. The oil supply passage 49 for supplying hydraulic oil to the reservoir chamber 55 and the hydraulic chamber 53 is provided, and the sliding clearance between the cylinder 18 and the plunger body 51 is larger than the sliding clearance between the cylinder 18 and the reservoir cap 61. While setting, the hollow 51c is provided in the outer peripheral surface of the plunger body 51. FIG.

  Accordingly, since the recess 51c is provided on the outer peripheral surface of the plunger body 51, the sliding resistance between the inner peripheral surface of the cylinder 18 and the outer peripheral surface of the plunger body 51 is reduced, and the plunger body 51 operates smoothly. Thus, the operability of the valve body 12 can be improved. As a result, fuel efficiency can be improved by easily improving the operability of the valve body 12 without increasing the cost of the product.

  Further, by providing the recess 51c on the outer peripheral surface of the plunger body 51, the weight can be reduced, which can contribute to the high rotation of the internal combustion engine. Further, since the hydraulic oil is accumulated in the recess 51c, seizure on the sliding surface between the cylinder 18 and the plunger body 51 can be suppressed, and vibration during the operation of the lash adjuster 28 is caused by the hydraulic oil accumulated in the recess 51c. Can be attenuated to reduce noise.

  In the electromagnetically driven valve 11, on the principle of operating using the resonance of the upper and lower springs 27, 32, the friction of the sliding part attenuates this resonance, which may lead to an operation error or inoperability. However, since the lash adjuster 28 provided with the depression 51 c on the outer peripheral surface of the plunger body 51 is applied to the electromagnetically driven valve 11, the sliding resistance between the inner peripheral surface of the cylinder 18 and the outer peripheral surface of the plunger body 51 is improved. Therefore, the operation of the lash adjuster 28 via the armature shaft 29 by electromagnetic force can be smoothly performed.

  In the lash adjuster 28 of the first embodiment, the sliding clearance between the cylinder 18 and the plunger body 51 is set larger than the sliding clearance between the cylinder 18 and the reservoir cap 61.

  Accordingly, supply of hydraulic oil to the armature 37, the coils 38, 40, the cores 39, 41 and the like positioned above the lash adjuster 28 is prevented, and the malfunction of the electromagnetically driven valve 11 can be suppressed, while the lash adjuster is suppressed. The hydraulic oil can be sufficiently supplied to the valve body 12 and the valve guide 21 located below the valve 28, and a lack of lubricating oil can be prevented to ensure a smooth operation of the valve body 12.

  FIG. 6 is a cross-sectional view of a lash adjuster according to the second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the second embodiment, as shown in FIG. 6, the lash adjuster 71 has a sliding clearance between the cylinder 18 and the plunger body 51 and a sliding clearance between the cylinder 18 and the reservoir cap 61, as in the first embodiment. It is set larger. The plunger body 51 has a recess 51c on its outer peripheral surface, and the reservoir cap 61 has a recess 61a on its outer peripheral surface. Each of the recesses 51c and 61a is formed on the outer peripheral surface of the plunger body 51 and the reservoir cap 61 at the center and over the entire circumference over a region shorter than the axial length.

  Accordingly, when the lash adjuster 71 is operated, the depression 51 c is provided on the outer circumferential surface of the plunger body 51 and the depression 61 a is provided on the outer circumferential surface of the reservoir cap 61, so that the inner circumferential surface of the cylinder 18 and the plunger body 51 are The sliding resistance between the outer peripheral surface and the inner peripheral surface of the cylinder 18 and the outer peripheral surface of the reservoir cap 61 is reduced, and the lash adjuster 71 as a whole operates smoothly. Is possible.

  As described above, in the lash adjuster 71 of the second embodiment, the depression 51 c is provided on the outer peripheral surface of the plunger body 51, and the depression 61 a is provided on the outer peripheral surface of the reservoir cap 61. Accordingly, sliding resistance between the inner peripheral surface of the cylinder 18 and the outer peripheral surfaces of the plunger body 51 and the reservoir cap 61 is reduced, and the lash adjuster 71 as a whole can be operated smoothly, and the operability of the valve body 12 is improved. can do. As a result, fuel efficiency can be improved by easily improving the operability of the valve body 12 without increasing the cost of the product.

  FIG. 7 is a sectional view of a lash adjuster according to the third embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the third embodiment, as shown in FIG. 7, the basic configuration of the lash adjuster 81 is the same as that of the first embodiment. In this embodiment, the lash adjuster 81 is applied not to an electromagnetically driven valve but to a valve mechanism of a cam mechanism. In other words, a cylindrical lifter 82 whose upper end is closed is fitted and fixed to the reservoir cap 61 from above. The cam 84 of the camshaft 83 can be pressed against the upper surface 82a of the lifter 82.

  Accordingly, a downward driving force is applied to the reservoir cap 61 by the cam 84. Further, the valve body 12 of the internal combustion engine is in contact with the lower end surface of the plunger body 51, and this valve body 12 is urged in the valve closing direction, that is, toward the plunger body 51 by a valve spring (not shown). Yes.

  When the camshaft 83 rotates from this state, a downward driving force is applied to the reservoir cap 61 by the cam 84, and the plunger 52 is pressed downward, whereby the hydraulic oil in the hydraulic chamber 53 is pressurized. When the hydraulic chamber 53 becomes high pressure and the communication path 56 is closed by the check ball 59, the driving force transmitted to the plunger 52 is transmitted to the plunger body 51 via the hydraulic chamber 53, and the reservoir cap 61 and the plunger 52 and the plunger body 51 are integrated and displaced downward to open the valve body 12.

  When the downward displacement of the reservoir cap 61, the plunger 52, and the plunger body 51 reaches the lowest point and the cam shaft 83 further rotates, the press of the reservoir cap 61 by the cam 84 is released, and the reservoir cap 61, the plunger 52, and the plunger are released. The body 51 is integrated and displaced upward. When the valve body 12 reaches the fully closed position, the reservoir cap 61 continues to move relatively gently upward, and when the hydraulic pressure in the hydraulic chamber 53 becomes low pressure, the check ball 59 opens the communication path 56 to increase the hydraulic pressure. The hydraulic oil in the chamber 53 flows into the reservoir chamber 55, and the plunger 52 slides upward while maintaining the state in contact with the reservoir cap 61.

  When such a lash adjuster 81 is operated, the depression 51 c is provided on the outer peripheral surface of the plunger body 51, so that the sliding resistance between the inner peripheral surface of the cylinder 18 and the outer peripheral surface of the plunger body 51 is reduced. As a result, the plunger body 51 can be smoothly operated, and the operability of the valve body 12 is improved.

  Thus, in the lash adjuster 81 of the third embodiment, the lash adjuster 81 is applied to a valve operating mechanism having the cam 84. Therefore, even in the valve mechanism having such a configuration, by providing the recess 51 c on the outer peripheral surface of the plunger body 51, the space between the inner peripheral surface of the cylinder 18 and the outer peripheral surfaces of the plunger body 51 and the reservoir cap 61 is increased. The sliding resistance is reduced, and the operability of the valve body 12 can be improved.

  In each of the embodiments described above, the depression 51c is provided in the plunger body 51 of the lash adjuster, or the depressions 51c and 61a are provided in the plunger body 51 and the reservoir cap 61. However, the depression 61a is provided only in the reservoir cap 61. Also good. Further, the number of the recesses 51c and 61a is not limited to one, and may be divided into a plurality, or may be divided in the circumferential direction.

  As described above, the lash adjuster according to the present invention is intended to improve the operability of the valve body by providing a depression on the outer peripheral surface of the plunger body or appropriately setting the clearance with the cylinder. It is useful when applied to a lash adjuster having any structure.

It is sectional drawing of the lash adjuster which concerns on Example 1 of this invention. It is the schematic for demonstrating the sliding clearance with the cylinder in the lash adjuster of Example 1, a plunger body, and a reservoir cap. It is the schematic showing the support structure of the armature shaft in the electromagnetically driven valve of Example 1. FIG. It is the schematic showing the support structure of the armature shaft in the electromagnetically driven valve of Example 1. FIG. It is the schematic showing the support structure of the armature shaft in the electromagnetically driven valve of Example 1. FIG. 3 is a graph showing the friction reduction effect by the lash adjuster of Example 1. It is sectional drawing showing the electromagnetically driven valve to which the lash adjuster of Example 1 was applied. It is sectional drawing of the lash adjuster which concerns on Example 2 of this invention. It is sectional drawing of the lash adjuster which concerns on Example 3 of this invention.

Explanation of symbols

11 Electromagnetically driven valve 12 Valve element 18 Cylinder head spacer (cylinder)
27 Lower spring 28, 71, 81 Rush adjuster 29 Armature shaft 29a, 29b Recess 32 Upper spring 37 Armature 38 Upper coil 39 Upper core 40 Lower coil 41 Lower core 48, 49 Oil supply path (supply oil path)
51 Plunger Body 51c Recess 52 Plunger 53 Hydraulic Chamber 55 Reservoir Chamber 56 Communication Path 58 Plunger Spring 59 Check Ball 61 Reservoir Cap 61a Recess 82 Lifter 83 Camshaft 84 Cam

Claims (2)

  A reservoir cap that is slidably supported along the axial direction inside the cylinder and has a valve operating mechanism at one end thereof, and a valve body that is slidably supported along the axial direction inside the cylinder and that has a valve element acting on one end thereof And a plunger body having a recess opening at the other end toward the reservoir cap, a plunger slidably received in the recess to form a hydraulic chamber between the plunger body, and the plunger In a lash adjuster comprising a spring urging in a direction in contact with the reservoir cap and a supply oil passage for supplying hydraulic oil to the hydraulic chamber, a sliding clearance between the cylinder and the plunger body is set between the cylinder and the A lash adjuster that is set larger than the sliding clearance with the reservoir cap. The lash adjuster according to claim 2 , wherein a depression is provided on an outer peripheral surface of the plunger body over a region shorter than an axial length.

Images