JP2000045721A - Cam follower with roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply fix a roller shaft to a support wall of a cam follower body without specially requiring a caulking equipment, and to certainly restrict the rotation and axial movement of the roller shaft in a cam follower with a roller. SOLUTION: A C-shaped first groove g1 extending along the peripheral direction of a cam follower body is formed on the inner periphery of a through hole 9b of one support wall Wb, and a C-shaped second groove g2 is formed opposite to the first groove g1 on the outer periphery of the one end 7b of the roller shaft 7, and a C-shaped elastic stopper L is attached in a C-shaped hollow part G formed between the first and the second groove g1, g2, and both the ends Lf of the stopper L are severally formed on a flat face inclined to an imaginary plane D to radially extend from the axis of the roller shaft O toward the end of the stopper L and on the other hand, both the inner end faces Gf of the hollow part G opposite to both the end faces Lf are formed on flat faces severally parallel to both the end faces of the stopper L.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cam follower body in which a pair of support walls are arranged integrally so as to sandwich rollers therebetween, and the rollers are rotated in through holes formed in both support walls. The present invention relates to a cam follower with a roller that supports the outer periphery of both ends of a roller shaft that is freely supported.

[0002]

2. Description of the Related Art The above-mentioned cam follower with a roller is designed to enhance the slidability and followability of the cam follower with respect to the cam by means of a roller in contact with the cam, and has been widely used in valve gears for internal combustion engines. ing.

In the conventional cam follower with a roller, a method of fixing a roller shaft is disclosed in, for example,
No. 321999, the both ends of the shaft are swaged by punching with a punch or a bolt-shaped roller shaft as shown in Japanese Utility Model Laid-Open No. 57-98350. There has been known a structure in which the shaft end is fastened and fixed with a nut outside a support wall.

[0004]

However, the above-mentioned fixing by caulking has a problem that the cost is increased because specially required caulking equipment, and especially when a hollow roller shaft is used, the caulking is caused by the caulking. The roller shaft is liable to be deformed or distorted, so that the roller rolling surface is not smooth, and the roller may not be able to rotate smoothly on the rolling surface.

On the other hand, in the above-mentioned fixing with the bolt and nut, the head and nut of the bolt protrude from the outer surface of the support wall, and the width of the cam follower (the maximum dimension in the direction along the roller shaft) becomes unnecessarily large. There is.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cam follower with a roller which can solve the above-mentioned problems and disadvantages of the conventional one.

[0007]

According to a first aspect of the present invention, there is provided a cam follower body having a pair of support walls which are arranged side by side so as to sandwich rollers therebetween.
In a cam follower with a roller in which the outer circumferences of both ends of a roller shaft for rotatably supporting the roller are fitted and supported in respective through holes formed in both support walls, the inner circumference of the through hole of one of the support walls is provided. The surface has a C-shaped first groove extending along the circumferential direction thereof, and the outer peripheral surface of one end of the roller shaft has the same C-shaped second groove corresponding to the first groove.
A groove is formed, and a C-shaped elastic stopper that can be engaged across the inner surfaces of both grooves is mounted in a C-shaped hollow portion formed between the first and second grooves. Then, the axial relative movement and relative rotation of the roller shaft and the support wall are regulated, and both end surfaces of the stopper are positioned with respect to an imaginary plane extending radially from the roller axis to the end of the stopper. It is characterized in that, while being formed on each of the inclined flat surfaces, both inner end surfaces of the hollow portion opposed to them are formed on flat surfaces respectively parallel to both end surfaces of the stopper.

According to this feature, the C-shaped elastic stopper provided between the fitting surfaces of the roller shaft and the support wall through-hole (C-shaped hollow portion) is provided in the axial direction relative to the support wall through-hole of the roller shaft. Since the sliding and relative rotation can be reliably prevented, the roller shaft can be easily fixed to the support wall without using special caulking equipment, and the roller shaft is fixed to the outer surface of the support wall. There is no overhang portion for this, and the width of the cam follower can be narrowed accordingly, and even if the roller shaft is hollow, there is no possibility that the roller shaft will be deformed or distorted as in the case of caulking. Also, especially each end face of the stopper,
The flat surface is inclined with respect to an imaginary plane extending radially from the roller axis to the end of the stopper, while the inner end surface of the hollow portion facing the flat surface is a flat surface parallel to the end surface of the stopper. As a result, the end face of the stopper and the inner end face of the hollow portion (each groove) can come into surface contact with each other with a sufficiently large contact area, and they are accurately engaged with each other, and a sufficient detent effect is exhibited. In addition, the contact surface pressure between them is reduced, which is effective for reducing the wear of the contact portion (that is, the end face of the stopper, the inner end face of the first and second grooves).

According to a second aspect of the present invention, in addition to the features of the first aspect, each inner end surface of the hollow portion extends radially outward from an outer peripheral edge portion of a stopper end surface opposed to the inner end surface. According to this feature, a V-shaped recess (corresponding to the starting point of stress concentration) corresponding to the outer edge of the end face of the stopper is formed on the inner end face of the first groove in the support wall. (Easy) is not formed, so that generation of cracks and cracks on the inner end face of the first groove due to contact with the edge portion is effectively prevented.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below based on embodiments of the present invention illustrated in the accompanying drawings.

In the accompanying drawings, FIG. 1 is a cross-sectional view of an essential part showing an example of a valve train for an internal combustion engine incorporating a cam follower with a roller according to a first embodiment, and FIG. FIG. 3 is a sectional view taken along line 3-3 of FIG. 2 and a partially enlarged view of FIG. 2, FIG. 4 is an exploded perspective view of a cam follower with a roller according to the first embodiment, and FIG.
FIG. 6 is an explanatory view for simply explaining a groove forming process.
FIG. 4 is a sectional view corresponding to FIG.

First, a first embodiment in which the cam follower with a roller according to the present invention is applied to a valve train of a four-cycle internal combustion engine will be described with reference to FIGS.

In FIG. 1, a rocker arm body 2 of a rocker arm 1 as a cam follower has a shaft hole 2a formed at a longitudinally intermediate portion thereof, and a rocker arm fixed to an engine body E of an internal combustion engine is formed in the shaft hole 2a. The shaft 3 is penetrated so as to be relatively rotatable. An adjust bolt 4 is screwed into the base of the rocker arm body 2, and the screwed position is fixed by a lock nut 5. An upper end of an engine valve V (for example, an intake valve or an exhaust valve) supported slidably up and down on the engine body E is in contact with a lower end of the adjustment bolt 4. It is constantly urged in the valve closing direction (the direction of contact with the adjustment bolt 4) by the generated force.

A roller R is rotatably attached to the tip of the rocker arm body 2 via a roller shaft 7. The outer peripheral surface of the roller R is pressed against a valve cam C as a cam based on the resilience of the valve spring 6, and the valve cam C is supported by the engine main body E and has a crankshaft (not shown). Z)
Are formed integrally with the outer periphery of the valve gear camshaft 8 which rotates in conjunction with. When the valve operating cam C rotates, the rocker arm main body 2 that comes into contact with the cam C via the roller R moves to the rocker shaft 3.
By swinging up and down around, the engine valve V can be opened and closed.

Next, the mounting structure of the roller R and the roller shaft 7 will be specifically described with reference to FIGS. A fork-shaped roller holding portion H having first and second support walls Wa and Wb arranged in parallel at intervals so as to sandwich the roller R therebetween is integrally formed at the leading end of the rocker arm body 2. In each of the support walls Wa and Wb, through-holes 9a and 9b crossing them are formed on the same axis, and the outer circumferences of both ends of the roller shaft 7 are fitted and supported in the through-holes 9a and 9b, respectively. You.

The roller shaft 7 is formed in a hollow cylindrical shape which is open at both ends and has the same diameter over the entire length. The inner periphery of the roller R is arranged in the circumferential direction at the outer periphery of a central portion 7m in the longitudinal direction. It is rotatably supported via a number of needles N.
Further, both outer end surfaces of the roller shaft 7 are formed so as not to protrude from both outer surfaces of both support walls Wa and Wb (particularly, in the illustrated example, to be flush with both outer surfaces). On the other hand, each support wall W
The through holes 9a and 9b of a and Wb are formed in arc holes having the same inner diameter over the entire width, and the inner diameter is set to be substantially the same as the outer diameter of the roller shaft 7.
a and 7b are tightly fitted (that is, slidable but without backlash).

One support wall (the second support wall W in the illustrated example)
The through-hole 9b in the peripheral surface of b), the first groove g ₁ of C-shaped cross section extending in the circumferential direction is formed. The roller shaft 7
Of, on the outer peripheral surface of the end portion 7b corresponding to the second support wall Wb, cross-section extending in the circumferential direction corresponding to the first groove g ₁ C
Second groove g ₂ is formed shaped. Thus, the through hole 9b
A C-shaped hollow portion G is formed between the first and second grooves g ₁ and g ₂ between the fitting surfaces of the roller shaft 7 and one end portion 7 b of the roller shaft 7. A metal circlip L formed in a C-shape having substantially the same shape as the above is attached, and this circlip L constitutes an elastic stopper of the present invention.

When the circlip L is set in the hollow portion G, one end surface of the circlip L straddles the inner surfaces of one end of the grooves g ₁ and g ₂ , and the other end surface of the circlip L has both ends g _1. , G
₂ so as to be able to prevent relative rotation between the roller shaft 7 and the support walls Wa and Wb by making contact with each other across the inner surface of the other end of the circlip L. astride the said two grooves g _1, one side inner surface of g ₂ over, also the other side surface over the entire circumference at both groove g _1, g ₂ of the other side the inner surface so as to straddle By making contact with each other, relative axial movement between the roller shaft 7 and the support walls Wa and Wb can be prevented.

Also, as clearly shown in FIG.
Are flatly formed on the entire surface. Moreover, each of the end faces Lf is closer to a virtual plane D extending radially from the axis O of the roller shaft 7 toward the end of the circlip L, and the end faces Lf are closer to each other outward in the radial direction of the circlip L. To both sides, and at the same time, both inner end faces Gf of the hollow portion G facing them (that is, both inner end faces of the first and second grooves g ₁ and g ₂ ).
Are formed on flat surfaces parallel to the both end surfaces Lf of the circlip L (and thus similarly inclined with respect to the virtual plane D). Thereby, each end face L of the circlip L
f, and each inner end face Gf of the hollow portion G facing in parallel with this
And can make surface contact with a sufficiently large contact area, so that the mutual engagement is accurate and a sufficient detent effect is exhibited, and the contact surface pressure between them is effectively reduced, This is extremely effective in reducing abrasion of the contact portion (that is, the circlip end face Lf and the inner end face Gf of the hollow portion G).

Further, each inner end face Gf of the hollow portion G extends longer than the outer peripheral edge portion Lfe of the end face Lf of the circlip L opposed thereto to the outside in the radial direction, and the extended end is formed by the first end. It is smoothly continuous with the edge of the first groove g ₁ end arcuate groove r formed by depressing the bottom surface. This allows
The inner end surface of the first groove g _1, since the circlip L end face Lf outer peripheral side edge portion Lfe V-shaped recess corresponding to the in (such recess tends to be a starting point of stress concentration) is not formed, the edge the by the contact between the portion Lfe of cracks or cracks in the first inner end face of the groove g ₁ is generated can be effectively prevented.

[0021] The circlip L is in its free state, the outside diameter of the roller shaft 7 (therefore through-hole 9a, the inner diameter of 9b) than, the first groove g ₁ of the inner diameter is formed to be larger in diameter cage, therefore the outer peripheral surface of the circlip L with the set state to the hollow portion G is pressed against the first inner bottom surface of the groove g ₁ based on the elastic restoring force of the circlip L itself. The second groove g ₂ in the roller shaft 7, until retracts the circlip L fitted thereto in the second groove g ₂ (i.e. the outer diameter of the circlip L is not more than the outside diameter of the roller shaft 7) The groove depth is set so that the first jig (not shown) can be forcibly elastically contracted and deformed. In addition, between the both ends of the circlip L and the inner ends of the C-shaped hollow portion G, the circlip L can be easily elastically deformed in the radial direction when the circlip L is assembled. Some play is set in the circumferential direction.

[0022] In manufacturing the rocker arm 1 of the structure, first, to prepare a rocker arm main body 2, then cutting the first groove g ₁ in the through hole 9b of the second support wall Wb in the roller holding portion H . When processing of the first groove g _1, first the inner peripheral surface of the through hole 9b by sending a grooving cutter Cg, as shown in (a) of FIG. 5 along the inner periphery of the through hole 9b in an arc cutting the first main part of the groove g _1, then both inner end faces Gf of the groove g ₁ as (b), the
An end mill fed in the same direction so as to be a flat surface inclined by a predetermined angle θ with respect to the imaginary plane D, and to extend longer than the outer peripheral edge portion Lfe of the end surface Lf of the circlip L to the outside in the radial direction. And other cutters (not shown).

On the other hand, the roller shaft 7 is manufactured in a process different from the manufacturing process of the rocker arm main body 2, and thereafter, a second groove g ₂ is cut around the outer periphery of one end 7 b of the shaft 7, and the second shaft g ₂ is cut. the second groove g ₂ Prefer fitting the circlip L.

Next, the roller R, on which a large number of needles N are temporarily assembled, is mounted on the inner periphery of the first and second support walls W of the rocker arm body 2.
The roller R is provided between the supporting walls Wa and Wb in the gap between the supporting walls Wa and Wb.
Is inserted and held using a second jig (not shown) so as to be coaxial with the through holes 9a and 9b, and the roller shaft 7 is held in this holding state with the other end 7a first and the first , Second
The grooves g ₁ and g ₂ are sequentially inserted into the through-hole 9b and the roller R of the second support wall Wb so that the phases of the grooves g ₁ and g ₂ are matched with each other. 9b. As the time of insertion, it keeps forced retention advance circlip L by the first jig (not shown) to the elastic contractive state of being immersed into the second groove g _2. When the circlip L reaches the inside of the through hole 9b with the insertion, the circlip L is released from the first jig and the through hole 9b
Sliding an inner and come becomes extended deformation by its own elastic restoring force into the first groove g ₁ and normal set state to a position corresponding to the first groove g _1. Thereby, the roller shaft 7 can be integrally fixed to the second support wall Wb (accordingly, the rocker arm main body 2).

As described above, the C-shaped elastic circlip L that can be engaged across the inner surfaces of the first and second grooves g ₁ and g ₂ allows the shaft between the roller shaft 7 and the support walls Wa and Wb to be engaged. Since the directional relative movement and relative rotation are prevented, the roller shaft 7 can be easily fixed to the rocker arm main body 2 without specially requiring caulking equipment, thereby achieving cost reduction. Moreover, there is no protrusion on the outer surfaces of the support walls Wa and Wb for fixing the roller shaft, and the width of the rocker arm 1 (the maximum dimension in the roller shaft direction) is correspondingly reduced.
And the rocker arm 1 can be reduced in size.

In the illustrated example, the roller shaft 7 is formed hollow for the purpose of reducing the weight of the rocker arm 1 or the like. However, even with such a hollow structure, the roller shaft 7 may be deformed or deformed as in the case of caulking. There is no risk of distortion, and the roller rolling surface (the outer peripheral surface of the central portion 7m) can be formed smoothly, so that the roller R can always be smoothly rotated on the rolling surface.

The roller shaft 7 is large from the cam C.
Each support wall W of the roller shaft 7 receives a hit load.
a, Wb and roller R (needle N)
Is the one where the maximum shearing force is exerted by the hitting load
However, in the present embodiment, the second groove g _TwoIs from the above boundary corresponding part
Are also spaced apart in the axial direction, so that the groove g_TwoFeatures
Of the above-mentioned boundary corresponding part due to installation (specifically, deformation
And breakage) are effectively suppressed.

[0028] In a further illustrated embodiment, the first groove g ₁ C-shaped formed in the through hole 9b in the periphery of the support wall Wb at the rocker arm body 2 as the cam follower body, the rocker arm as shown in FIG. 3 to be (the groove g ₁ is not to position or on the side corresponding to the rocker shaft 3) arranged to unevenly distributed on the free end side of the main body 2, the rocker arm 1 has its free end is C-shaped first groove conformability to the cam is lighter is enhanced by the formation of g _1, thereon, the arcuate groove r is formed at both ends of the first groove g _1, r is the rocker arm body 2 of the (support wall Wb) , Respectively, in the radially thick portion around the through hole 9b.
The rigidity reduction of the rocker arm main body 2 (support wall Wb) due to the formation of r can be effectively avoided.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, each end face Lf of the circlip L as an elastic stopper is oriented in the opposite direction to the virtual plane D from the first embodiment (that is, with respect to the virtual plane D,
The circlip L has the same configuration as that of the first embodiment except that it is inclined toward the radially outward side of the circlip L by a predetermined angle θ toward the side where the both end faces Lf are separated from each other. The same effect as in the first embodiment can be expected.

Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments, and various embodiments are possible within the scope of the present invention. For example, in the above embodiment, the roller shaft 7 is formed in a hollow cylindrical shape, but in the present invention, the roller shaft 7 may be formed in a solid cylindrical shape. In the above embodiment, the circlip L as an elastic stopper is used.
In a state that was allowed to elastically contracted and deformed into the second groove g ₂ in the roller shaft 7 by inserting the roller shaft 7 in the through hole 9b of the support walls Wb, the first groove of the through hole 9b of the circlip L g
_In the present invention, the circlip L serving as an elastic stopper is attached to the support wall W.
In b while being elastically expanded deformed into the first groove g ₁ in the through hole 9b of, by inserting the roller shaft 7 in the through hole 9b of the support walls Wb, the said circlip L of the roller shaft 7 2 it may be brought into contraction engagement into the groove g ₂ side. Further, in the above-described embodiment, the direction in which the both end surfaces Lf of the circlip L as the elastic stoppers are inclined with respect to the virtual plane D is set to be opposite to each other. However, in the present invention, the inclination direction of the both end surfaces Lf is set. May be set in the same direction.

[0031]

As described above, according to the first aspect of the present invention,
In a cam follower with a roller, a C-shaped first groove formed on an inner peripheral surface of a through hole of one support wall and a C-shaped second groove formed on an outer peripheral surface of one end of a roller shaft are formed between each other. A C-shaped elastic stopper that can be engaged across the inner surfaces of both grooves is attached to the C-shaped hollow portion to be engaged in the axial relative movement and relative rotation between the roller shaft and the support wall. The roller shaft can be easily fixed to the support wall without specially using caulking equipment, and an overhang for fixing the roller shaft is provided on the outer surface of the support wall. It does not exist, and the width of the cam follower can be reduced accordingly.

In particular, each end surface of the stopper is a flat surface inclined with respect to an imaginary plane radially extending from the roller axis toward the end of the stopper, while the inner end surface of the hollow portion opposed to them is Since the flat surface is parallel to the end surface of the stopper, the end surface of the stopper and the inner end surface of the hollow portion (each groove) opposed thereto can be brought into surface contact with a sufficiently large contact area. And the roller shaft can be reliably prevented from rotating, and the contact surface pressure between the end face of the stopper and the inner end face of the hollow portion (each groove) can be effectively reduced, greatly reducing the wear of the contact portion. Can contribute.

According to the second aspect of the present invention, each inner end surface of the hollow portion extends radially outward from the outer peripheral edge portion of the end surface of the stopper facing the inner end surface.
V corresponding to the above-mentioned edge of the end face of the stopper is provided on the inner end face of the groove.
There is no U-shaped concave portion (such a concave portion is likely to be a starting point of stress concentration), so that cracks and cracks are effectively prevented from being generated on the inner end face of the first groove due to contact with the edge portion. Therefore, the support strength of the roller shaft by the support wall can be increased.

[Brief description of the drawings]

FIG. 1 is a sectional view of an essential part showing an example of a valve train for an internal combustion engine incorporating a cam follower with a roller according to a first embodiment.

FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1;

3 is a sectional view taken along line 3-3 of FIG. 2 and a partially enlarged view thereof.

FIG. 4 is an exploded perspective view of a cam follower with a roller according to the first embodiment.

FIG. 5 is an explanatory diagram for simply explaining a processing step of a first groove in the cam follower main body.

FIG. 6 is a sectional view corresponding to FIG. 3, showing a main part of the second embodiment;

[Explanation of symbols]

D · · · · circlip as imaginary plane G · · · · hollow portion Gf · · · in the end surface g ₁ · · · first groove g ₂ · · · second groove L · · · · elastic fastener Lf · ··· End face Lfe ··· Outer peripheral edge portion O ··· Roller axis axis Wa ··· Second support wall as support wall Wb ··· First support wall as one support wall 1 ··· Cam follower Rocker arm 2 as a rocker arm body as a cam follower body 7 roller roller 7a other end 7b one end 9a, 9b.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G016 AA02 AA19 BA02 BA05 BB18 BB22 CA01 CA04 CA13 CA32 CA40 CA44 CA45 CA46 CA52 FA36 GA00 GA01 GA02 GA05

Claims (2)

[Claims] 1. A pair of support walls (Wa, Wb), which are arranged side by side so as to sandwich a roller (R) therebetween, are integrally formed on a cam follower body (2), and are respectively formed on both support walls (Wa, Wb). In a cam follower with a roller, the outer periphery of both ends (7a, 7b) of a roller shaft (7) rotatably supporting the roller (R) is fitted and supported in the formed through holes (9a, 9b). On the inner peripheral surface of the through hole (9b) of the one support wall (Wb), a C-shaped first groove (g ₁ ) extending along the circumferential direction is provided, and one end of the roller shaft (7) ( 7b) On the outer peripheral surface, the first
A second C-shaped groove (g ₂ ) corresponding to the groove (g ₁ ) is formed, and a C-shaped groove formed between the first and second grooves (g ₁ , g ₂ ). In the hollow part (G), both grooves (g
₁ , g ₂ ), a C-shaped elastic stopper (L) that can be engaged across the inner surface of the roller shaft (7) is attached to the roller shaft (7) and the support wall (Wa, Wb) in the axial direction. Movement and relative rotation are restricted, and both end faces (Lf) of the stopper (L) are formed on a virtual plane (D) extending radially from the roller axis (O) toward the end of the stopper (L). The hollow portions (G) which are formed on flat surfaces inclined with respect to each other, and opposed to them.
Of the inner end faces (Gf) of the stopper (L).
A cam follower with a roller, wherein the cam follower is formed on flat surfaces parallel to each other. 2. Each inner end surface (Gf) of the hollow portion (G).
The cam follower with a roller according to claim 1, wherein the cam follower extends radially outward from an outer peripheral edge portion (Lfe) of a stopper end surface (Lf) facing the stopper.