JP2018044463A - Valve lifter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve lifter capable of improving abrasion resistance by preventing lubrication failure caused by cocking.SOLUTION: A valve lifter 10 includes an ended cylindrical lifter body 11 which is stored in a lifter guide and reciprocally slides on an inner peripheral surface of the lifter guide by receiving turning force of a cam 50. The lifter body 11 has a retreat surface which is inclined in multiple steps or is inclined in a form of a curved surface without steps to a direction separating from the inner peripheral surface of the lifter guide in an end of a reciprocating slide direction to the lifter guide.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a valve lifter.

  Patent Document 1 discloses a valve lifter having an inverted cup shape from a cylindrical side wall portion and a disk-like end wall portion that closes the upper end of the side wall portion. The side wall portion is slidable in the vertical direction in the guide hole of the cylinder head, and the end wall portion is pressed by a rotating cam. In the case of Patent Document 1, the side wall is provided with a meandering concave shape, and by ensuring the oil in the meandering concave shape, the side wall can be lubricated uniformly and the wear resistance can be improved. Yes.

JP 2003-269115 A

  This type of valve lifter receives a load in the direction crossing the reciprocating movement direction (vertical direction) according to the cam profile of the cam when reciprocating in the guide hole. There is a case of so-called cocking. At this time, of the upper and lower end portions of the side wall portion, the portion facing the outer peripheral surface of the cam in the rotational direction of the cam hits the inner peripheral surface of the guide hole, and between this portion and the inner peripheral surface of the guide hole The oil film formed on the surface may break. Such oil film breakage increases the amount of wear on the outer peripheral surface of the valve lifter, resulting in poor lubrication.

  The present invention has been completed based on the above circumstances, and an object of the present invention is to provide a valve lifter that can prevent poor lubrication due to cocking and can improve wear resistance.

  The valve lifter according to the present invention includes an end-cylinder-shaped lifter body that is housed in a lifter guide and reciprocally slides on an inner peripheral surface of the lifter guide in response to a rotational force of a cam. The lifter body includes the lifter guide. It has a feature in that it has a retracting surface that is inclined in a curved shape without multiple steps or steps in the direction away from the inner peripheral surface of the lifter guide at the end in the reciprocating sliding direction.

  When the lifter body reciprocates and slides on the inner peripheral surface of the lifter guide due to the rotational force of the cam, even if the lifter body tilts in the lifter guide, the end of the lifter body in the reciprocating sliding direction is Since it is possible to avoid hitting the inner peripheral surface by the retreating surface, it is difficult for the oil film to break and to prevent insufficient lubrication. As a result, improvement in wear resistance can be realized. In particular, since the retracting surface is inclined in a curved shape without multiple steps or steps in a direction away from the inner peripheral surface of the lifter guide, the reciprocating slide of the lifter body is different from the case where it is simply chamfered into a tapered shape. It is easy to avoid the end portion in the moving direction from coming into contact with the inner peripheral surface of the lifter guide, and the risk of oil film breakage can be further reduced.

In the valve lifter of Example 1 of this invention, it is sectional drawing of the valve lifter used for the valve operating apparatus. It is a front view of the lifter main body inclined in the lifter guide. FIG. 3 is an enlarged view of a main part of FIG. 2. FIG. 3 is a front view of a lifter body tilted to the opposite side to FIG. 2. FIG. 3 is a view corresponding to FIG. 2 for a valve lifter according to a second embodiment of the present invention. FIG. 4 is a view corresponding to FIG. 3 in a valve lifter of Embodiment 2.

Preferred embodiments of the present invention are shown below.
The retracting surface may be provided over the entire circumference at both ends of the lifter body in the reciprocating sliding direction. According to this, even if the lifter body rotates and tilts in the lifter guide, there is always a retraction surface at a position facing the outer peripheral surface of the cam, and it is possible to more reliably prevent insufficient lubrication. be able to.

  The end face of the lifter body may contact the cam without a roller. If the valve lifter comes into contact with the cam via the roller, the valve lifter is provided with a fork structure that supports the end of the rotating shaft of the roller or a structure that prevents the lifter body from rotating, and the valve lifter tilts within the lifter guide and breaks the oil film. There is relatively little concern that this will occur. On the other hand, if the valve lifter does not have a roller as in this configuration, the lifter body tends to tilt in the lifter guide, and therefore it is significant to improve the wear resistance by the retracting surface.

<Example 1>
A first embodiment of the present invention will be described with reference to FIGS. In the following description, the vertical direction is based on each figure, and includes an aspect in which it is inclined obliquely with respect to the direction of gravity during use.

  The valve operating apparatus shown in FIG. 1 opens and closes a guide hole 81 having a circular cross section provided through a cylinder head 80 in the vertical direction, and an intake / exhaust port of the internal combustion engine, and within the guide hole 81 (inside the lifter guide). A valve 70 having a stem 71 protruding to the top, a valve lifter 10 inserted into the guide hole 81 and biased upward by a spring material 60 connected to the stem 71 via a retainer 65, and an upper surface of the valve lifter 10. And a substantially egg-shaped cam 50 that reciprocates the valve lifter 10 in the vertical direction by rotating about the shaft portion 51.

  The valve lifter 10 is composed of an inverted cup-shaped lifter main body 11 and is rotatable around an axis within the guide hole 81. The lifter body 11 includes a cylindrical peripheral wall portion 12 and a disk-shaped end wall portion 13 that closes the upper end of the peripheral wall portion 12.

  The central portion of the end wall portion 13 is formed thicker than the peripheral portion, the build-up portion 14 protrudes downward, and the flat lower surface (inner surface) of the build-up portion 14 is in contact with the upper end of the stem 71. The upper surface (outer surface) of the end wall portion 13 is in sliding contact with the cam 50 at the center portion and is pressed downward by the rotating cam 50.

  A portion of the outer peripheral surface of the peripheral wall portion 12 excluding the upper and lower end portions is arranged substantially along the vertical direction, and can be slid against the inner peripheral surface of the guide hole 81 (the inner peripheral surface of the lifter guide). The outer surface 15 is used. The inner peripheral surface of the peripheral wall portion 12 is also disposed substantially along the vertical direction.

  The upper end portion of the outer peripheral surface of the peripheral wall portion 12 is multi-step inward from the upper end of the outer peripheral surface 15 (upper image line portion 21A described later) to the upper surface of the end wall portion 13 (the side away from the inner peripheral surface of the guide hole 81) The upper retracting surface 16A is inclined to the upper side. Specifically, the upper retreat surface 16A is formed over the entire circumference on the outer peripheral surface of the peripheral wall portion 12, and, as shown in FIGS. 2 and 3, is a two-stage process with different inclination angles with the upper switching portion 17A as a boundary. It is comprised by the 1st, 2nd upper side slope 18A, 19A. The upper switching portion 17 </ b> A is an annular line that is continuous at the same height on the outer peripheral surface of the peripheral wall portion 12.

  The first upper slope 18A is disposed below the upper switching portion 17A, and the vertical formation range is sufficiently larger than the second upper slope 19A. The first upper inclined surface 18A is inclined in a tapered shape with a constant inclination angle with respect to the vertical direction, and the inclination angle is an inclination angle when the lifter body 11 is inclined to the maximum with respect to the vertical direction in the guide hole 81. Has been bigger than.

  The second upper inclined surface 19A is disposed above the upper switching portion 17A and has substantially the same form as the conventional chamfered portion. The second upper inclined surface 19A is inclined in a tapered shape with a constant inclination angle with respect to the vertical direction, and the inclination angle is larger than the inclination angle of the first upper inclined surface 18A.

  The first upper slope 18A and the second upper slope 19A are connected to each other at an obtuse angle via the upper switching portion 17A, and also intersect with the circumferential outer surface 15 at an obtuse angle. The first upper slope 18A and the outer circumferential surface 15 are partitioned by an upper image portion 21A as an annular line parallel to the upper switching portion 17A.

  As shown in FIG. 1, the entire vertical range of the second upper slope 19 </ b> A is included in the vertical thickness range of the end wall portion 13. On the other hand, the vertical formation range of the first upper slope 18A has a portion that exceeds the vertical thickness range of the end wall.

  As shown in FIG. 2, the outer peripheral surface of the peripheral wall portion 12 has a substantially vertically symmetrical shape, and the lower end portion of the outer peripheral surface of the peripheral wall portion 12 has a lower retraction surface 16B corresponding to the upper retraction surface 16A. It is said that. The lower retraction surface 16B is gradually inclined inward (side away from the inner peripheral surface of the guide hole 81) from the lower end of the circumferential outer surface 15 (lower image line portion 21B described later) to the lower end of the lifter body 11 in a multi-step manner. It is in form. Specifically, the lower retreat surface 16B is constituted by two stages of first and second lower inclined surfaces 18B and 19B having different inclination angles with the lower switching portion 17B as a boundary. The lower switching portion 17B is an annular line that is continuous at the same height on the outer peripheral surface of the peripheral wall portion 12.

  The first lower slope 18B is disposed above the lower switching portion 17B, and the vertical range is sufficiently larger than the second lower slope 19B. The first lower inclined surface 18B is inclined in a tapered shape with a constant inclination angle with respect to the vertical direction, and the inclination angle is substantially the same as that of the first upper inclined surface 18A. It is larger than the tilt angle when tilted to the maximum with respect to the direction.

  The second lower inclined surface 19B is disposed below the lower switching portion 17B and has substantially the same form as the conventional chamfered portion. The inclination angle of the second lower slope 19B is tapered with a constant inclination angle with respect to the vertical direction, and the inclination angle is larger than the inclination angle of the first lower slope 18B.

  The first lower slope 18B and the second lower slope 19B are connected to each other at an obtuse angle via the upper switching portion 17A, and also intersect with the circumferential outer surface 15 at an obtuse angle. A space between the first lower slope 18B and the outer circumferential surface 15 is defined by a lower drawing portion 21B as an annular line parallel to the lower switching portion 17B.

Next, the operation of the first embodiment will be described.
When the cam 50 rotates and the outer peripheral surface of the cam 50 slides on the upper surface of the end wall portion 13 and a downward pressing force acts on the lifter body 11, the lifter body 11 descends while compressing the spring material 60. Then, the valve 70 opens the intake / exhaust port. When the cam 50 further rotates, the lifter body 11 rises due to the urging force of the spring material 60, and the valve 70 closes the intake / exhaust port. Thus, the lifter body 11 slides back and forth in the vertical direction in accordance with the rotation of the cam 50. At this time, lubricating oil is supplied between the outer peripheral surface of the peripheral wall portion 12 and the inner peripheral surface of the guide hole 81 so that an oil film is formed so that the lifter body 11 can smoothly reciprocate.

  During rotation of the cam 50, a portion of the lifter body 11 that faces the outer peripheral surface of the cam 50 in the rotational direction of the cam 50 receives a load in the left-right direction intersecting the vertical direction, and is in contact with the inner peripheral surface of the guide hole 81. Cocking that vibrates so as to be alternately tilted to the left and right in the guide hole 81 may occur in the gap range.

  If cocking occurs, the lifter body 11 tilts in the guide hole 81 as shown in FIG. 2, and the upper left end and lower right end of the lifter body 11 approach the inner peripheral surface of the guide hole 81. When the upper right end and the lower left end of the lifter body 11 are separated from the inner peripheral surface of the guide hole 81, the upper image portion 21A and the lower image portion 21B come into contact with the inner peripheral surface of the guide hole 81. The upper retracting surface 16A and the lower retracting surface 16B escape away from the inner peripheral surface of the guide hole 81 and do not contact the inner peripheral surface of the guide hole 81. Further, as shown in FIG. 4, the lifter body 11 is inclined to the opposite side in the guide hole 81, and the upper right end portion and the lower left end portion of the lifter body 11 approach the inner peripheral surface of the guide hole 81. Even when the upper left end portion and the lower right end portion of the lifter body 11 are separated from the inner peripheral surface of the guide hole 81, the upper drawing portion 21 </ b> A and the lower drawing portion 21 </ b> B are arranged on the inner periphery of the guide hole 81 as described above. The upper retracting surface 16 </ b> A and the lower retracting surface 16 </ b> B are not in contact with the inner peripheral surface of the guide hole 81.

  In the above description, the upper image portion 21 </ b> A and the lower image portion 21 </ b> B are merely lightly obtusely in contact with the inner peripheral surface of the guide hole 81 at positions that are not the upper and lower ends of the lifter body 11. The first upper slope 18A and the first lower slope 18B are not in contact with the inner peripheral surface of the guide hole 81 because the inclination angle is set larger than the maximum inclination angle of the lifter body 11. Can be maintained. For this reason, the state in which the oil film of the lubricating oil is formed between the outer peripheral surface of the peripheral wall portion 12 and the inner peripheral surface of the guide hole 81 is well maintained, and a situation in which the oil film is cut can be avoided. As a result, the valve lifter 10 capable of preventing poor lubrication due to cocking and improving wear resistance is provided.

  In particular, in the case of the first embodiment, the upper retracting surface 16 </ b> A and the lower retracting surface 16 </ b> B are provided over the entire circumference at the upper and lower end portions of the lifter body 11, so that the lifter body 11 tilts while rotating in the guide hole 81. However, the upper retracting surface 16A and the lower retracting surface 16B always exist at positions facing the outer peripheral surface of the cam 50, and it is possible to more reliably prevent insufficient lubrication.

<Example 2>
5 and 6 show a second embodiment of the present invention. The second embodiment is different from the first embodiment in the form of the upper retracting surface 16AD and the lower retracting surface 16BD. However, the upper retraction surface 16AD is formed over the entire circumference at the upper end portion of the outer peripheral surface of the peripheral wall portion 12, and the lower retraction surface 16BD is formed over the entire periphery at the lower end portion of the outer peripheral surface of the peripheral wall portion 12. It is the same as Example 1, and forms other than upper retraction surface 16AD and lower retraction surface 16BD are also the same as Example 1. Therefore, the same reference numerals are given to structures that are the same as or correspond to those in the first embodiment, and redundant descriptions are omitted.

  The upper retreating surface 16AD has a shape that infinitely inclines in a curved shape from the upper end of the outer circumferential surface 15 to the upper surface of the end wall 13 toward the inside (the side away from the inner circumferential surface of the guide hole 81). Specifically, the upper retraction surface 16AD is connected to the circumferential outer surface 15 of the peripheral wall portion 12 in an R shape via the upper image line portion 21AD, and is connected to the upper surface of the end wall portion 13 in an R shape so as to have an arc having a constant curvature. It is formed along.

  Similarly, the lower retreating surface 16BD has a shape that is steplessly curved inwardly from the lower end of the circumferential outer surface 15 to the lower end of the lifter main body 11, and is formed on the lower side of the circumferential outer surface 15 of the circumferential wall portion 12. It is connected in an R shape via the image line portion 21BD, and is connected in an R shape to the lower surface of the end wall portion 13, and is formed along an arc having a constant curvature. The upper retracting surface 16AD and the lower retracting surface 16BD are formed with the same curvature, and are disposed symmetrically with respect to the upper and lower centers of the outer peripheral surface of the peripheral wall portion 12.

  When the lifter body 11D reciprocates vertically in the guide hole 81 and the portion of the lifter body 11D facing the outer peripheral surface of the cam 50 in the rotation direction of the cam 50 is inclined, the upper image portion 21AD and While the R surface of the lower drawing portion 21BD comes into contact with the inner peripheral surface of the guide hole 81, the upper retracting surface 16AD and the lower retracting surface 16BD escape away from the inner peripheral surface of the guide hole 81 and It is designed not to touch. In this case, the upper retracting surface 16AD and the lower retracting surface 16BD are set so as to be separated from the inner peripheral surface of the guide hole 81 even when the lifter body 11D is tilted to the maximum extent in the guide hole 81. The state which does not contact the inner peripheral surface of the hole 81 can be maintained. As a result, it is possible to avoid a situation in which the oil film between the outer peripheral surface of the peripheral wall portion 12 and the inner peripheral surface of the guide hole 81 is cut, to prevent insufficient lubrication, and to improve wear resistance. Can be planned.

  In particular, in the case of Example 2, the upper withdrawal surface 16AD and the lower withdrawal surface 16BD are curved, and the upper drawing portion 21AD and the lower drawing portion 21BD that contact the inner peripheral surface of the guide hole 81 by cocking are also respectively provided. Since an R shape is formed between the upper retracting surface 16AD and the lower retracting surface 16BD and the circumferential outer surface 15, the inner peripheral surface of the guide hole 81 is not hit by an angle, and the occurrence of oil film breakage can be avoided more reliably. be able to.

<Other embodiments>
Other embodiments will be briefly described below.
(1) In Example 1, the upper inclined surface and the lower inclined surface may be configured by three or more stages of tapered surfaces having different inclination angles.
(2) Also in the first embodiment, as in the second embodiment, the upper image portion and the lower image portion have an R shape between the first upper inclined surface and the first lower inclined surface and the circumferential outer surface. It may be.
(3) In Examples 1 and 2, the upper and lower end portions of the peripheral wall portion are overlaid on the inner peripheral surface facing the upper retraction surface and the lower retraction surface to prevent the rigidity of the peripheral wall portion from being lowered. It may be the structure to do.
(4) In the first and second embodiments, when the end wall portion of the lifter body always protrudes from the guide hole, the upper inclined surface may not be provided at the upper end portion of the outer peripheral surface of the peripheral wall portion.

DESCRIPTION OF SYMBOLS 10 ... Valve lifter 11, 11D ... Lifter main body 16A, 16AD ... Upper retraction surface (retraction surface)
16B, 16BD: Lower retraction surface (retraction surface)
50 ... Cam 80 ... Cylinder head 81 ... Guide hole

Claims (3)

The lifter guide is housed in a lifter guide, and is provided with an end-cylinder lifter body that reciprocally slides on the inner peripheral surface of the lifter guide in response to the rotational force of a cam.
The lifter body has a retraction surface that is inclined in a curved shape without a step or a step in a direction away from the inner peripheral surface of the lifter guide at an end in a reciprocating sliding direction with respect to the lifter guide. Valve lifter to do.   The valve lifter according to claim 1, wherein the evacuation surface is provided over the entire circumference at both ends of the lifter body in the reciprocating sliding direction.   The valve lifter according to claim 1 or 2, wherein an end surface of the lifter main body contacts the cam without a roller.

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