JP3761766B2 - Cam follower - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cam follower such as a rocker arm that is tilted by a cam to open and close a valve provided in a cylinder head.
[0002]
[Prior art]
In general, a cam follower (hereinafter referred to as a rocker arm) is configured to open and close a valve provided in a cylinder head by being tilted by a cam. For example, an end pivot as shown in FIGS. There is what is called a type.
[0003]
The end pivot type rocker arm 50 shown in the figure is provided with a pair of sheet metal roller support walls 51 and 52 facing the body substantially parallel to each other, and a punching process is performed at an intermediate position in the longitudinal direction of each of the roller support walls 51 and 52. The insertion holes 62 and 63 are formed, and a support shaft 55 is passed between the insertion holes 62 and 63 as shown by phantom lines in the figure, and the cam 55 is connected to the support shaft 55 via a plurality of needle rollers 56. A roller 54 with which 53 is in rolling contact is externally provided.
[0004]
Further, a valve receiving portion 58 with which the upper end of the valve 57 abuts is provided on one end side of the roller support walls 51, 52, and the upper end of the lash adjuster 59 abuts on the other end side of the roller support walls 51, 52. The pivot receiving part 60 is provided, and the whole pivots around the pivot receiving part 60 as a fulcrum.
[0005]
[Problems to be solved by the invention]
As shown in FIG. 7, the rocker arm 50 holds the needle roller 56 on the inner peripheral surface side of the roller 54 by a synthetic rubber holding member (also referred to as a holding plug) 61, thereby holding the holding member 61 and the needle roller 56. The assembly of the roller 54 is mounted between the roller support walls 51, 52, and in this state, the support shaft 55 is inserted through the insertion hole 62 formed in the one roller support wall 51, and the holding member 61 is inserted into the other roller support wall. 52 so as to be pushed out from the insertion hole 63 formed in 52.
[0006]
By the way, since the insertion holes 62 and 63 of the roller support walls 51 and 52 are formed by punching, the outer periphery of the insertion hole 63 is angular. For this reason, when the holding member 61 is pushed out from the insertion hole 63 formed in the other roller support wall 52 by the support shaft 55, the holding member 61 is scraped at the outer peripheral corner portion of the insertion hole 63 to generate cutting waste. Sometimes. And if this cutting waste remains on the spot, it will have a bad influence on rotation of the needle roller 56 or the roller 54, and the rocker arm 50 cannot operate | move smoothly.
[0007]
Accordingly, an object of the present invention is to provide a cam follower that can solve the above-described problems.
[0008]
[Means for Solving the Problems]
The problem-solving means in the present invention has support walls arranged in parallel and opposed to each other in the body, and both support walls are formed with insertion holes through which the support shafts are inserted. A cam follower configured to open and close a valve provided on a cylinder head by disposing a roller on which the cam is brought into contact via a roller for bearing, and the body being displaced via the roller by rotation of the cam. In the state where a plurality of bearing rollers are pressed and held by the holding member on the inner peripheral surface of the roller and the roller and the bearing roller are assembled between the support walls, the support shaft is placed outside the insertion hole of one support wall. The support member is pushed out from the insertion hole of the other support wall and is inserted so that the support shaft passes between the insertion holes, and at least the support member on the side from which the holding member is pushed out is supported. Formed on the wall The inner opening edge of the insertion hole is chamfered into a curved surface, and the inner surface of the support wall around the inner opening edge chamfered into the curved surface is a guide plane that guides the end surface of the bearing roller, and the insertion hole The chamfer dimension of the inner opening edge is set to half of the outer diameter dimension of the bearing roller. The material of the holding member is preferably made of rubber or synthetic resin.
[0009]
According to this configuration, the plurality of bearing rollers are pressed and held on the inner peripheral surface of the roller by the holding member, and the support shaft is inserted into the one support wall in a state where the roller and the bearing roller are assembled between the support walls. When the holding member is inserted from the outside of the hole so that the holding member is pushed out from the insertion hole of the other support wall and the support shaft is passed between the insertion holes, the holding member can be inserted through the insertion hole of the other support wall without difficulty. The holding member is prevented from being cut at the outer peripheral corner of the insertion hole of the other support wall.
[0010]
In addition, the periphery of the opening of the insertion hole on the inner surface facing the support wall is a guide surface that guides the shaft end surface of the bearing roller, and the chamfer dimension of the inner opening edge of the insertion hole is the outer diameter dimension of the bearing roller. because it is set to half, when the roller bearing is guided on the inner surface of the support wall, and the inner surface of the end face and the support wall of the roller bearings is a state of surface contact, rollers smoothly the support wall bearing Guided.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a rocker arm according to an embodiment of the present invention will be described with reference to FIGS. A rocker arm (in this case, an end pivot type) R according to an embodiment of the present invention is attached to an OHC type engine, and is disposed in parallel with each other as shown in an exploded perspective view of FIG. 1 and a sectional view of FIG. The body 3 has a pair of roller support walls 1 and 2, and a roller 5 to which the cam 4 rolls is attached via a plurality of needle rollers 6 and a support shaft 7 in the middle in the longitudinal direction. A valve receiving portion 3a with which the upper end of the valve 8 is brought into contact with one end in the longitudinal direction of the walls 1 and 2 is formed, and the upper end of the lash adjuster 9 is fitted into the other end in the longitudinal direction of the both roller support walls 1 and 2. The pivot receiving portion 3b is formed, and is configured to be swingable with the pivot receiving portion 3b as a fulcrum.
[0012]
That is, the body 3 is formed by punching a single metal plate into a shape as shown in FIG. 5 (a), punching the insertion holes 11 and 12 at the longitudinal intermediate positions of the roller support walls 1 and 2, respectively, The outer peripheral portion of the insertion hole 12 is chamfered 12a in a circular arc shape, and the portion shown by the broken line in FIG. 5 is bent to the state shown in FIG. To do.
[0013]
By doing in this way, the inner opening edge part of each insertion hole 11 and 12 turns into a guide surface which guides the axial end surface of the said needle roller 6. FIG. And the chamfering 12a dimension of the inner side opening edge part of the insertion hole 12 is set to the half of the outer diameter dimension of the said needle roller 6, for example.
[0014]
Thereafter, as shown in FIG. 5 (c), the pivot receiving portion 3b is formed into a hemispherical shape by drawing at approximately the center of the connecting portion of the roller support walls 1 and 2, and as shown in FIG. 5 (d). As described above, the body 3 is manufactured by joining the separate valve receiving portions 3a by welding.
[0015]
As shown in FIG. 1, the valve receiving portion 3a is a rectangular flat plate bent in a substantially M shape in a side view, and is formed to be curved so that the top plate 13 bulges downward. The outer surface of the hanging wall portion 14 is joined in a state where it is applied to the inner surfaces of the roller support walls 1 and 2.
[0016]
Next, as shown in FIG. 3, a plurality of needle rollers 6 are attached to the inner peripheral surface of the roller 5 as shown in FIG. These assemblies are assembled between the roller support walls 1 and 2 while being pressed and held by the stopper 15. Then, by pushing the support shaft 7 from the outside of the insertion hole 11 of one roller support wall 1, the holding member 15 is pushed out from the insertion hole 12 of the other roller support wall 2 and the support shaft 7 is inserted into both insertion holes. The rocker arm R is manufactured as shown in FIG.
[0017]
When the support shaft 7 is pushed from the outside of the insertion hole 11 of one roller support wall 1 and the holding member 15 is pushed out from the insertion hole 12 of the other roller support wall 2 in this way, Since the opening edge portion is chamfered 12a in an arc shape, the holding member 15 is easily deformed and smoothly and smoothly pushed out from the insertion hole 12 of the other roller support wall 2, so that the holding member 15 is held as in the conventional case. It is possible to avoid a state in which cutting scraps are generated by cutting the member 15 at the inner opening edge of the insertion hole 12 of the other roller support wall 2. This prevents the adverse effect on the rotation of the needle rollers 6 and the rollers 5 due to the cutting waste, and the rocker arm R can operate smoothly.
[0018]
In the embodiment of the present invention, as shown in FIG. 2, the roller 5 is in contact with the cam 4 in the use state, and the body 3 is displaced while the roller 5 rotates around the support shaft 7 by the rotation of the cam 4. However, at this time, the end surfaces of the needle rollers 6 are guided to the inner surfaces of the roller support walls 1 and 2.
[0019]
By the way, in the embodiment of the present invention, the outer peripheral portion of the insertion hole 12 is chamfered 12a in an arc shape, but when the needle roller 6 is guided to the inner surfaces of the roller support walls 1 and 2, the needle roller 6 It is necessary to prevent the end portion from entering the chamfered portion 12a. However, in the embodiment of the present invention, the chamfer 12a dimension of the inner opening edge of the insertion hole 12 is set to half of the outer diameter dimension of the needle roller 6, so that the needle roller 6 enters the chamfer 12a portion. In addition, when the needle roller 6 is guided to the inner surfaces of the roller support walls 1 and 2, the end surface of the needle roller 6 and the inner surfaces of the roller support walls 1 and 2 (particularly the roller support wall 2) are The surface contact is made, and the needle rollers 6 are smoothly guided to the roller support walls 1 and 2.
[0020]
The valve receiving portion 3a is formed to be curved so that the top plate 13 bulges downward. In the rocker arm R provided with such a valve receiving portion 3a, the rocker arm R with respect to the cylinder head is provided. When there is almost no assembly error or mounting error of the valve receiving portion 3a with respect to both roller support walls 1 and 2, the top plate 13 portion of the valve receiving portion 3a is in contact with the substantially upper center of the valve 8 Therefore, even if the valve receiving portion 3a is inclined with respect to the valve 8 due to the above-described assembly error or mounting error, the top plate 13 portion of the valve receiving portion 3a is almost at the center of the upper end surface of the valve 8. The contact state is maintained, and the contact state can be maintained normally.
[0021]
That is, in this embodiment, the top plate 13 portion of the valve receiving portion 3a comes into contact with the upper end surface of the valve 8 regardless of the inclination of the valve receiving portion 3a. It is possible to prevent the edge load from being generated in 3a, prevent the valve receiving portion 3a from being unevenly worn, and prevent damage such as pitching, thereby extending the life and stable operation.
[0022]
In the above embodiment, the rocker arm R has been described as an end pivot type, but the present invention is not limited to this, and the present invention can also be applied to a center pivot type rocker arm R. In this center pivot type rocker arm R, a roller 5 with which a cam 4 is brought into rolling contact with each other via a plurality of needle rollers 6 and a support shaft 7 is disposed at one end in a longitudinal direction between a pair of roller support walls 1 and 2 facing substantially parallel. Is attached to the other end in the longitudinal direction between the roller support walls 1 and 2, and a valve receiving portion 3 a with which the upper end of the valve 8 abuts is provided. A shaft is attached, and the body 3 swings around the other support shaft.
[0023]
Even when the rocker arm R having such a configuration is assembled, the holding member 15 is inserted into the other roller support wall 2 by applying an arc-shaped chamfer 12 a to the inner opening edge of the insertion hole 12. Therefore, the holding member 15 is prevented from being scraped at the inner opening edge of the insertion hole 12 of the other roller support wall 2, and the needle rollers 6 and the rollers 5 are rotated by the cutting waste. Can be operated smoothly.
[0024]
Although the rocker arm R in which the inner opening edge portion of the insertion hole 12 of the roller support wall 2 is chamfered 12a in a circular arc shape is attached to the OHC type engine as in the above embodiment, it is limited to this. Instead, for example, it may be used for a rocker arm R attached to an OHV type engine.
[0026]
In the above embodiment, the inner opening edge of the insertion hole 12 of the roller support wall 2 is chamfered 12a in an arc shape, but the present invention is not limited to this, and the support shaft 7 is inserted into the insertion hole of one roller support wall 1. 11, when the holding member 15 is pushed out from the insertion hole 12 of the other roller support wall 2, the holding member 15 is pushed out from the insertion hole 12 of the other roller support wall 2. Further, the chamfer 12a may be chamfered to a curve other than the arc, and in this case, the same effect as that of the above embodiment can be obtained.
[0027]
In the above embodiment, only the inner opening edge of the insertion hole 12 of the other roller support wall 2 is chamfered 12a in a circular arc shape, but the present invention is not limited to this, and at the time of production shown in FIG. The inner opening edge of both the insertion hole 11 of the roller support wall 1 and the insertion hole 12 of the other roller support wall 2 or only the inner opening edge of the insertion hole 11 of one roller support wall 1 is chamfered. May be.
[0028]
In this case, contrary to the above embodiment, the support shaft 7 is inserted from the insertion hole 12 of the other roller support wall 2 toward the insertion hole 11 of the one roller support wall 1, and the holding member 15 is inserted into one of the support members 15. When pushing out from the insertion hole 11 of the roller support wall 1, the holding member 15 can be prevented from being scraped by the inner opening edge of the insertion hole 11 of one of the roller support walls 1. Thus, a rocker arm R capable of smoothly operating while preventing adverse effects on the rotation of the roller 5 is obtained.
[0029]
【The invention's effect】
As is apparent from the above description, the present invention has an inner opening edge in the insertion hole formed in at least one of the support walls of the body that is displaced by the rotation of the cam. In a state where a plurality of bearing rollers are pressed and held on the inner peripheral surface of the roller, the roller and the bearing roller are assembled between the support walls, and the support shaft is pushed from the outside of the insertion hole of one support wall. Prevents the holding member from being scraped at the inner opening edge of the insertion hole of the other support wall when the holding member is pushed out from the insertion hole of the other support wall and the support shaft is passed between both insertion holes. Thus, generation of cutting waste can be suppressed, thereby preventing adverse effects on the rotation of the bearing rollers and the rollers, thereby enabling smooth operation.
[0030]
The chamfer dimension of the inner opening edge of the insertion hole, since the set half of the outer diameter of the roller bearings, the ends of the roller bearings can be prevented from entering the chamfered portion, also, roller bearings support wall When the inner surface of the bearing roller is guided, the end surface of the bearing roller and the inner surface of the support wall come into surface contact, and the bearing roller is smoothly guided to the support wall.
[Brief description of the drawings]
FIG. 1 is an exploded view of a rocker arm showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a usage state of the rocker arm.
FIG. 3 is a cross-sectional view illustrating a procedure for manufacturing a rocker arm.
FIG. 4 is a cross-sectional view showing a state in which the support shaft is similarly inserted through the other insertion hole.
FIG. 5 is a plan view for explaining the same procedure for manufacturing the body.
FIG. 6 is a view showing a usage state of a conventional rocker arm.
FIG. 7 is a cross-sectional view illustrating a procedure for manufacturing a rocker arm.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Roller support wall 2 Roller support wall 3 Body 4 Cam 5 Roller 6 Needle roller 7 Support shaft 11 Insertion hole 12 Insertion hole 15 Holding member R Rocker arm

Claims (2)

A roller having support walls arranged in parallel and opposed to each other in the body, and through holes formed in the support walls through which the support shafts are inserted. A roller on which the cam rolls on the outer periphery of the support shaft between the support walls. Is a cam follower configured to open and close a valve provided on the cylinder head by the body being displaced via a roller by rotation of a cam.
A plurality of bearing rollers are pressed and held on the inner peripheral surface of the roller by the holding member, and the support shaft is inserted from the outside of the insertion hole of one support wall in a state where the roller and the bearing roller are assembled between the support walls. As a result, the holding member is pushed out from the insertion hole of the other support wall and installed so as to pass the support shaft between the insertion holes,
Of the two support walls, at least the inner opening edge in the insertion hole formed in the support wall on the side where the holding member is pushed out is chamfered into a curved surface,
Support wall inner surface around the curved surface shape chamfered inner opening edge portion is a guide plane that guides an end face of the roller for the bearing, and the chamfer dimension of the inner opening edge of the insertion hole, outside the roller bearing Cam follower characterized in that it is set to half the diameter.   2. The cam follower according to claim 1, wherein the holding member is made of rubber or synthetic resin.

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