JP2013189926A - Lash adjuster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow air accumulating on a lower surface (a ceiling surface of a high-pressure oil chamber) of the bottom of a plunger to be easily released to the outside.SOLUTION: A tapered surface 50, that becomes higher as going to a valve seat 31, is formed on a lower surface of the bottom 26 of a plunger 20, including the valve seat 31 at the central part, in order to collect air in a high-pressure oil chamber 15, floating up to the lower surface, at the periphery of the valve seat 31. The tapered surface 50 is a plane of rotation formed by rotating a straight line L, inclined in the horizontal direction, about the axis X of the plunger.

Description

  The present invention relates to a hydraulic lash adjuster that automatically adjusts a valve clearance.

  A general hydraulic lash adjuster 90 (Patent Document 1) shown in FIG. 6 has a lower portion of a plunger 92 inserted into an upper portion of a body 91, and between the bottom of the body 91 and the bottom of the plunger 92, A high pressure oil chamber 97 is formed, and a low pressure oil chamber 98 is formed above the bottom of the plunger 92. A through hole 93 is provided at the bottom of the plunger 92 to allow oil to flow from the low pressure oil chamber 98 to the high pressure oil chamber 97 when the plunger 92 is extended, and a check valve 95 is provided at the lower opening edge. ing.

  Such a general hydraulic lash adjuster 90 supports a rocker arm (not shown) on the upper end portion of the plunger 92 so as to be able to swing, and inputs an input load from the rocker arm by the hydraulic pressure of the high pressure oil chamber 97. The basic function is to apply a damping force when the plunger 92 is retracted and retracted.

JP 2004-278377 A

  Oil of the hydraulic lash adjuster 90 is pumped out of an oil pan (not shown) by an oil pump, and then supplied to the high pressure oil chamber 97 via an oil passage (not shown) and the low pressure oil chamber 98. In the meantime, air E may be bitten. As shown in FIG. 7A, the air E bitten in the high-pressure oil chamber 97 floats by buoyancy and accumulates on the bottom surface of the bottom of the plunger 92 (the ceiling surface of the high-pressure oil chamber 97). As shown in FIG. 7B, the air E accumulated on the bottom surface of the plunger 92 passes through the check valve 95 every time the plunger 92 is fed and the check valve 95 is opened. The air passes through the through-hole 93, but if the speed and frequency of removal are not sufficient, a large amount of air E still remains on the bottom surface of the plunger 92. The accumulated air E is compressed when the plunger 92 is retracted, so that the plunger 92 is easily retracted, and the basic function of the lash adjuster 90 such as applying a damping force to the plunger 92 is impaired. . If the basic function is impaired in such a manner, the amount of retraction (plunging amount) of the plunger 92 when the valve (not shown) is pressed by the rocker arm is increased, so that the valve is lifted in a shocking manner. There is a risk that the valve will be damaged by being seated on the portion (not shown), or that the clearance of the valve operating system will increase and the support of the rocker arm by the plunger 92 will become unstable.

  Therefore, it is an object to make it easy for air accumulated on the bottom surface of the bottom of the plunger (the ceiling surface of the high pressure oil chamber) to escape to the outside.

  In order to solve the above-described problems, a lash adjuster according to the present invention is configured such that a lower portion of a plunger including a cylinder and a bottom is inserted into an upper portion of a body including a cylinder and a bottom so that the plunger can be extended and retracted. A high-pressure oil chamber is formed between the bottom of the plunger, a low-pressure oil chamber is formed above the bottom of the plunger, and a through-hole is provided in the bottom of the plunger for flowing oil from the low-pressure oil chamber to the high-pressure oil chamber when the plunger is extended. A check valve including a check ball and a check spring for biasing the check ball to the valve seat below the valve seat. In the lash adjuster provided with a taper surface, which becomes higher toward the valve seat, is formed on the lower surface of the bottom of the plunger to collect the air in the high pressure oil chamber that has floated up to the lower surface around the valve seat. It is characterized in.

  Here, the width of the tapered surface in the horizontal direction is not particularly limited, but it is preferable that the outer diameter of the skirt of the tapered surface is larger than the outer diameter of the check ball in plan view. Furthermore, it is preferable that the outer diameter of the skirt of the tapered surface is larger than the inner diameter of the low-pressure oil chamber in plan view. This is because the wider the taper surface in the horizontal direction, the more air can be collected around the valve seat from the lower surface of the bottom surface of the plunger.

  The tapered surface is not particularly limited, but is preferably a rotating surface formed by rotating a straight line or a curved line inclined with respect to the horizontal direction around the axis of the plunger.

  Moreover, although a taper surface is not specifically limited, It is preferable to include the part whose inclination | tilt angle with respect to a horizontal direction is 1-58.5 degrees. This is because if the inclination angle is 1 ° or more, it is easy to collect air on the bottom surface of the plunger, and if the inclination angle is 58.5 ° or less, the taper surface becomes too steep so that the plunger is near the hem. This is because there is no worry that the thickness of the bottom of the wall becomes too thick in the vertical direction.

  According to the present invention, even if air enters the high-pressure oil chamber, the air is collected around the valve seat by the tapered surface when it rises. Therefore, when the plunger is extended and the check valve is opened, the air in the high-pressure oil chamber easily escapes from between the valve seat and the check ball into the through hole.

1 is a front cross-sectional view showing a lash adjuster of Example 1. FIG. It is a perspective view which shows the plunger of the lash adjuster of Example 1. FIG. (A) is front sectional drawing which shows the bottom in the normal time of the plunger of the lash adjuster of Example 1, (b) is the lower surface sectional drawing. (A) is front sectional drawing which shows the bottom at the time of extension of the plunger of the lash adjuster of Example 1, (b) is the lower surface sectional drawing. (A) is front sectional drawing which shows the bottom of the plunger of the lash adjuster of Example 2, (b) is front sectional drawing which shows the bottom of the plunger of the lash adjuster of Example 3, (c) is the lash adjuster of Example 4. It is a front sectional view showing the bottom of the plunger. It is front sectional drawing which shows the lash adjuster of a prior art example. (A) is front sectional drawing which shows the bottom in the normal time of the plunger of the lash adjuster of a prior art example, (b) is front sectional drawing which shows the bottom at the time of the extension of the plunger.

  The lash adjuster 9 according to the first embodiment shown in FIGS. 1 to 4 includes a body 10, a plunger 20, a through hole 30, a leak gap 40, and a tapered surface 50 described below. 3B and 4B, a retainer 38, a check spring 37, and a feeding spring 19 which will be described later are not shown.

  The body 10 is a bottomed cylindrical member having a cylinder 11 extending in the vertical direction and a bottom 16 integrally formed at the lower end thereof, and the lower part of the plunger 20 is inserted into the upper part of the cylinder 11. . A high-pressure oil chamber 15 is formed between the bottom 16 of the body 10 and the bottom 26 of the plunger 20, and a feeding spring 19 for feeding the plunger 20 upward by elastic force is formed in the high-pressure oil chamber 15. Is provided. The cylinder 11 of the body 10 is provided with an outer oil supply hole 12 through which oil O flows from an external oil passage (not shown) into the low pressure oil chamber 25 of the inner plunger 20. A ring-shaped seal 13 for sealing the inside of the body 10 is attached to the upper end portion of the cylinder 11.

  The plunger 20 includes a cylinder 21 extending in the vertical direction, a hemispherical hemispherical part 23 integrally formed at the upper end of the cylinder 21, and a bottom 26 integrally formed at the lower end of the cylinder 21. A low pressure oil chamber 25 is formed between the hemispherical portion 23 and the bottom 26. Further, the hemispherical portion 23 is provided with an air vent hole 24 through which air in the low pressure oil chamber 25 is drawn upward. In addition, a cylindrical outer edge protrusion 27 protruding downward from the outer peripheral edge is provided on the outer peripheral edge of the bottom surface of the bottom 26. Further, the cylinder 21 is provided with an inner oil supply hole 22 through which the oil O from the outer oil supply hole 12 of the body 10 flows into the internal low-pressure oil chamber 25.

  The through hole 30 is a hole for allowing the oil O to flow from the low pressure oil chamber 25 to the high pressure oil chamber 15 when the plunger 20 is extended from the body 10. A valve seat 31 is provided at the lower opening edge of the through hole 30, and a check valve 35 is provided for the valve seat 31. The check valve 35 includes a check ball 36 provided below the valve seat 31, a retainer 38 that is press-fitted into the outer edge protrusion 27 to surround the check ball 36, a check ball 36, and a retainer 38. And a check spring 37 that urges the check ball 36 against the valve seat 31 with an elastic force.

  The leak gap 40 is a gap for leaking the oil O from the high-pressure oil chamber 15 to the low-pressure oil chamber 25 when the plunger 20 retreats into the body 10, and the leak gap 40 is between the inner peripheral surface of the cylinder 11 of the body 10 and the plunger 20. It is formed between the outer peripheral surface of the cylinder 21.

  The tapered surface 50 is a conical surface for collecting the air E in the high pressure oil chamber 15 that has floated up to the lower surface of the bottom 26 of the plunger 20 (the ceiling surface of the high pressure oil chamber 15) around the valve seat 31. Of the bottom surface of the bottom 26, the entire portion from the outer peripheral end of the valve seat 31 to the inner peripheral end of the outer edge protrusion 27 is provided. Therefore, the outer diameter D of the skirt of the tapered surface 50 is larger than the outer diameter D1 of the check ball 36 in plan view. Further, it is larger than the inner diameter D2 of the low pressure oil chamber 25 in plan view. Specifically, the taper surface 50 is a rotation surface formed by rotating a straight line L around the axis X toward the axis X of the plunger at an inclination angle θ of 1 to 58.5 ° with respect to the horizontal direction H ( Conical surface).

  According to the first embodiment, as shown in FIG. 3, even when the air E enters the high pressure oil chamber 15, the air E is collected around the valve seat 31 by the tapered surface 50 when the air E floats. . Therefore, as shown in FIG. 4, when the plunger 20 is extended from the body 10 and the check valve 35 is opened, the air E in the high-pressure oil chamber 15 passes through the through hole 30 between the valve seat 31 and the check ball 36. It is easy to come off. Therefore, it is difficult for the air E to accumulate in the high-pressure oil chamber 15, and thus there is no fear that the plunger 20 easily retreats into the body 10.

  The lash adjuster 9a of the second embodiment shown in FIG. 5A differs from the tapered surface 50 of the first embodiment only in the tapered surface 50a, and the other portions are the same as those of the first embodiment. The taper surface 50a is a rotation surface formed by rotating a curve Ca (convex upward) toward the axis X of the plunger 20 obliquely with respect to the horizontal direction around the axis X. According to the second embodiment, the same effect as that of the first embodiment can be obtained.

  The lash adjuster 9b of the third embodiment shown in FIG. 5B is different from the tapered surface 50 of the first embodiment only in the tapered surface 50b, and the other portions are the same as the first embodiment. The taper surface 50b is a rotation surface formed by rotating a curve Cb (convex downward) toward the axis X of the plunger 20 obliquely with respect to the horizontal direction around the axis X. According to the third embodiment, the same effect as that of the first embodiment can be obtained.

  The lash adjuster 9c of the fourth embodiment shown in FIG. 5C is different from the tapered surface 50 of the first embodiment only in the tapered surface 50c, and the other portions are the same as those of the first embodiment. The taper surface 50c is a rotation surface formed by rotating a bending line Lc (consisting of a straight line L1 and a straight line L2) obliquely with respect to the axis line X of the plunger 20 around the axis line X. According to the fourth embodiment, the same effect as that of the first embodiment can be obtained.

  In addition, this invention is not limited to the structure of the said Examples 1-4, It can also change and actualize in the range which does not deviate from the meaning of invention.

9 Rush Adjuster 10 Body 11 Body Tube 15 High Pressure Oil Chamber 16 Body Bottom 20 Plunger 21 Plunger Tube 25 Low Pressure Oil Chamber 26 Plunger Bottom 30 Through-hole 31 Valve Seat 35 Check Valve 36 Check Ball 37 Check Spring 40 Leak Clearance 50 Tapered surface 50a Tapered surface 50b Tapered surface 50c Tapered surface O Oil E Air D Tapered hem outer diameter D1 Check ball outer diameter D2 Low pressure oil chamber inner diameter L Straight line L1 Straight line (part of broken line)
L2 straight line (part of broken line)
Ca curve Cb curve

Claims (4)

A lower part of a plunger (20) having a cylinder (21) and a bottom (26) is inserted into an upper part of a body (10) having a cylinder (11) and a bottom (16) so as to be extended and retracted. A high pressure oil chamber (15) is formed between the bottom (16) and the bottom (26) of the plunger, and a low pressure oil chamber (25) is formed above the bottom (26) of the plunger (20),
A through hole (30) through which oil flows from the low-pressure oil chamber (25) to the high-pressure oil chamber (15) when the plunger (20) is fed to the bottom (26) of the plunger is provided, of the lower surface of the plunger bottom (26) A valve seat (31) is formed at the lower opening edge of the through hole (30), and a check ball (36) and the check ball (36) are biased to the valve seat (31) below the valve seat (31). A lash adjuster provided with a check valve (35) including a check spring (37)
On the lower surface of the bottom (26) of the plunger, a tapered surface (which increases toward the valve seat (31) for collecting the air in the high-pressure oil chamber (15) floating up to the lower surface around the valve seat (31) ( 50, 50a, 50b, 50c) is formed.   The lash adjuster according to claim 1, wherein the outer diameter (D) of the skirt of the tapered surface (50, 50a, 50b, 50c) is larger than the outer diameter (D1) of the check ball (36) in plan view.   The lash adjuster according to claim 2, wherein the outer diameter (D) of the skirt of the tapered surface (50, 50a, 50b, 50c) is larger than the inner diameter (D2) of the low-pressure oil chamber (25) in plan view.   The tapered surfaces (50, 50a, 50b, 50c) are formed by rotating a straight line (L, L1, L2) or a curve (Ca, Cb) inclined with respect to the horizontal direction around the axis (X) of the plunger. The lash adjuster according to any one of claims 1 to 3, wherein the lash adjuster is a rotating surface.

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