JP2003278509A - Rocker arm and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily manufacture a rocker arm which receives the sliding operations of a cam to open/close a valve provided at a cylinder head without damaging a shaft at a low cost. <P>SOLUTION: This device comprises a pair of opposing side wall parts 7, 8 faced and disposed in roughly parallel to each other, a pivot part 9 and a valve abutting part 10 provided between both ends in a longitudinal direction of both the opposing side wall parts 7, 8 respectively. A body 2 coaxially having bearing recessed parts 11 is formed at inner surfaces which face each other at a roughly intermediate portion in the longitudinal direction of both the opposing side wall parts 7, 8, both ends of the spindle 3 in which a roller 4 is rotatably mounted at an outer part are pressed in the bearing recessed parts 11 with the roughly intermediate portion in the longitudinal direction of both the opposing side wall parts 7, 8 elastically deformed outward, and the shaft 3 is mounted between the opposing side wall parts 7, 8. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rocker arm that opens and closes a valve provided in a cylinder head in response to a sliding motion by a cam and a method for manufacturing the rocker arm.

[0002]

2. Description of the Related Art A conventional rocker arm 81 is shown in FIGS. The rocker arm 81 in the illustrated example has a body 8
2, it has a spindle 83, a roller 84, and a plurality of needle rollers 85.

The body 82 has a pair of side walls 86 and 87, a pivot portion 88 against which a lash adjuster 90 is abutted,
Valve abutting portion 8 against which the stem end of the valve 91 abuts
9 and 9. The support shaft 8 is provided between the pair of side walls 86 and 87.
A roller 84, on which the cam 92 is abutted, is rotatably supported on the outer periphery of the support shaft 83 via a plurality of needle rollers 85.

The support shaft 83 is inserted into the through holes 93, 94 provided in the pair of side walls 86, 87. Both end surfaces of the support shaft 83 are stamped and crimped to support the support shaft 83.
Is locked out.

In this embossing caulking, a punching tool or the like is used to form concave engraving grooves 95 on both end surfaces of the support shaft 83, and a wall portion that flows along with the formation of the engraving grooves 95 is formed on the side wall 8.
It is made to project around the through holes 93, 94 of 6, 87. This protruding portion serves as a claw 96 that prevents the support shaft 83 from coming out. In order to carry out such imprinting and crimping,
Usually, both ends of the support shaft 83 are set to be substantially flush with the outer openings of the through holes 93, 94.

The body 82 may be a cast product or a pressed product, and in any case, the above-mentioned method is used to prevent the spindle 83 from coming off.

[0007]

Usually, the outer peripheral surface of the support shaft 83 becomes the raceway surface of the needle roller 85, and therefore, it is necessary to perform a heat curing treatment. However, it is desirable not to cure both end portions of the support shaft 83 because of the relationship of stamping and crimping both end surfaces of the support shaft 83. Therefore, the support shaft 8
As the heat hardening treatment of No. 3, it is necessary to remove the both ends of the support shaft 83, for example. Also, in this heat curing treatment,
The processing area tends to shift in the axial direction. From such a thing,
A great deal of time and effort is required for the thermosetting process, resulting in an increase in manufacturing cost.

Further, since both end portions of the support shaft 83 are not cured, there is a problem that both end portions are easily damaged during the manufacturing process or transportation.

There is also a problem in that the steps of disposing the needle rollers 85 and the rollers 84 on the side walls 86 and 87, the step of inserting the support shaft 83, and the caulking step are required, and the number of manufacturing steps increases.

Further, a holding plug is required to prevent the needle rollers 85 from coming apart until the support shaft 83 is inserted.
There is also a problem that manufacturing becomes complicated.

An object of the present invention is to provide a rocker arm which can be manufactured easily and inexpensively without damaging a supporting shaft and a manufacturing method thereof.

[0012]

A rocker arm according to the present invention comprises a pair of opposed side walls arranged substantially parallel to each other, and a pivot part and a valve block provided between both ends of the opposed side walls in the longitudinal direction. A body including a contact portion, a support shaft that is provided between the opposite side wall parts and has at least an entire circumferential surface subjected to quench hardening treatment, and is rotatably mounted on the support shaft between the opposite side wall parts. A bearing recess is provided coaxially on the inner surfaces facing each other at approximately the middle in the longitudinal direction, and both ends of the support shaft are press-fitted into the bearing recess. And is installed between the opposite side wall portions.

It should be noted that whirl-stop portions are provided at both ends of the support shaft, and fitting portions into which the whirl-stop portions can be fitted are formed in the bearing recesses, and the whirl-stop portions are fitted to the fitting portions. In addition, both ends of the support shaft may be pressed into the bearing recesses.

According to the rocker arm manufacturing method of the present invention, a pair of opposing side wall portions are arranged substantially parallel to each other, and a pivot portion and a valve abutting portion are provided between both ends of the opposing side wall portions in the longitudinal direction. A state in which a body having a bearing concave portion is coaxially formed on inner surfaces of the opposite side wall portions facing each other at substantially intermediate portions in the longitudinal direction, and the substantially intermediate portions in the longitudinal direction of the opposite side wall portions are elastically deformed outward. With the roller rotatably mounted, at least both ends of the support shaft, which has been subjected to quench hardening treatment on the entire peripheral surface, are press-fitted into the bearing recesses,
It is characterized in that the support shaft is installed between the opposite side wall portions.

It should be noted that whirl-stop portions are provided at both ends of the support shaft, and fitting portions into which the whirl-stop portions can be fitted are formed in the bearing recesses, and the whirl-stop portions are fitted to the fitting portions. In addition, both ends of the support shaft may be pressed into the bearing recesses.

According to the rocker arm and the method for manufacturing the same of the present invention, the bearing concave portion formed on the inner surface of the opposing side wall portions is provided with
By pressing both ends of the support shaft, the support shaft can be installed between the opposite side wall portions. That is, approximately the middle portion in the longitudinal direction in which the bearing concave portions of the opposite side wall portions are formed is elastically deformed outward, and both ends of the support shaft are press-fitted into the bearing concave portions of the opposite side wall portions so that the support shaft is placed between the opposite side wall portions. To be installed.

As described above, since both ends of the support shaft are press-fitted from the inside of the body into the bearing recesses and the support shaft is installed between the opposite side wall portions, caulking for preventing the support shaft from coming off is unnecessary. Therefore, it is not necessary to form uncured portions for caulking on both ends of the support shaft, and the entire support shaft can be heat-cured.
It is not damaged during the manufacturing process or transportation, can be manufactured easily and inexpensively, and the surface hardness can be easily controlled to improve the quality.

Further, since both ends of the support shaft are press-fitted into the bearing recesses while the roller is rotatably covered, the support shaft and the roller can be mounted on the body at the same time, and the manufacturing process can be simplified. Moreover, even if the needle roller or the like is interposed between the support shaft and the roller, there is no concern that the needle roller will come loose during assembly, and the needle roller is separately held by the holding plug. There is no need, and the manufacturing process can be further simplified.

Further, by fitting the detent portions projecting at both ends of the support shaft into the fitting portions formed in the bearing recesses of the opposing side wall portions, the support shaft can be more reliably prevented from rotating. It can be installed between the opposite side wall portions.

[0020]

1 to 10 show one embodiment of the present invention. In this embodiment, an end pivot type rocker arm is taken as an example.

The end pivot type rocker arm 1 shown in FIG. 1 has a body 2, a support shaft 3, a roller 4, and a plurality of needle rollers 5.

The body 2 has a pair of opposing side wall portions 7 and 8 arranged substantially parallel to each other, and a pivot portion 9 provided between the opposing side wall portions 7 and 8 at the lower side at one longitudinal end thereof. It is a pressed product having a shape including a valve contact portion 10 provided between the other ends of the side wall portions 7 and 8 in the longitudinal direction.

The pivot portion 9 is provided with a hemispherical pivot 12 which bulges upward.

The valve contact portion 10 has a concave shape which is upside down when viewed from the end face, and the ceiling portion thereof has a shape which is bulged downward to warp.

On the inner surfaces of the opposite side wall portions 7 and 8 facing each other in the middle in the longitudinal direction, circular bearing recesses 11 which are coaxial with each other are formed.
Is provided, and both ends of the support shaft 3 are press-fitted into the bearing recess 11, so that the support shaft 3 is attached in a state of being bridged between the opposing side wall portions 7 and 8. A roller 4 is rotatably provided on the outer periphery of the support shaft 3 via a plurality of needle rollers 5 in a region between the opposing side wall portions 7 and 8.

The support shaft 3 is made of, for example, high carbon chromium bearing steel or carbon steel, and the whole of the support shaft 3 is heat-hardened. This thermosetting treatment should be performed by various other well-known techniques such as soaking quenching, carburizing quenching, and induction hardening so that the surface hardness of the support shaft 3 is set to, for example, Rockwell hardness (HRC) of 58 or more. You can Further, both ends of the support shaft 3 may be chamfered for general end surface treatment.

In such a rocker arm 1, the pivot 12 of the body 2 is engaged with the upper end of the lash adjuster 20 installed on the cylinder head (not shown), and the valve contact portion 10 is operated on the cylinder head. It contacts the stem end of the valve 21 of the mechanism, and
The cam 22 installed on the cylinder head is brought into contact with. Then, by rotating the cam 22, the body 2 can be tilted with the pivot 12 serving as a fulcrum, and the valve contact portion 10 is repeatedly displaced up and down by a predetermined stroke to open and close the valve 21. I will let you. In this way, the rocker arm 1 is tilted with one end side in the longitudinal direction of the body 2 as a fulcrum.

Now, a procedure for manufacturing the above-mentioned body 2 will be described.

First, as shown in FIG. 2, a substrate 2A such as a steel plate is blanked, and a pair of opposing side wall portions 7 and 8 are formed.
In the regions 2B and 2C to be defined as above, the bearing recess 11 is formed in the portion where the spindle 3 is to be inserted.

Subsequently, the region 2D to be the pivot portion 9 in the substrate 2A is subjected to a drawing process to form the hemispherically bulged pivot 12.

A sectional view taken along line III-III of FIG. 2 is shown in FIG.

Subsequently, after trimming and removing the outer peripheral unnecessary portion of the substrate 5A, as shown in FIG. 4, regions 2B and 2C which will become a pair of opposing side wall portions 7 and 8 in the substrate 5A.
Is bent into a substantially U shape so that the pair of opposed side wall portions 7 and 8 face each other substantially in parallel.

Then, a region 2E which becomes the valve contact portion 10
By pressing the (see FIG. 2), the valve contact portion 10 having the stem end insertion concave portion 13 on the lower surface.
To form. Note that FIG. 5 shows a view on arrow V in FIG.

Then, the entire body 2 is subjected to a heat curing treatment.

After that, the support shaft 3 formed by externally elastically deforming the substantially intermediate portion in the longitudinal direction in which the bearing recessed portions 11 of the pair of opposed side wall portions 7 and 8 are formed, and the roller 4 is exteriorly mounted via the needle roller 5.
Is pushed between the opposite side wall portions 7 and 8.

For example, as shown in FIG. 6 and FIG. 7, the upper sides of the opposing side wall portions 7 and 8 which are substantially in the middle in the longitudinal direction are elastically deformed outward, and the support shaft 3 is pushed in. Alternatively, approximately the middle of the opposing side wall portions 7, 8 in the longitudinal direction is curved outward in an arc shape, and the support shaft 3 is pushed in.

The work of elastically deforming the opposing side wall portions 7 and 8 outward is performed by, for example, interposing a jig between the opposing side wall portions 7 and 8 so as not to interfere with the attachment of the support shaft 3, and to make the opposing side wall portions 7 and 8 face each other. This is performed by applying a pressing force outward to the side wall portions 7 and 8.

Both ends of the support shaft 3 project outward from the roller 4, and the projecting portions are the bearing recesses 1 of the opposite side wall portions 7 and 8.
Pressed into 1.

As a result, the support shaft 3 is held in a state where it is prevented from rotating by the opposing side wall portions 7 and 8, and the roller 4 externally fitted through the needle roller 5 is rotatably abutted against the cam 22. Contact.

FIG. 8 is a plan view of the rocker arm 1 with the support shaft 3, the roller 4, and the needle roller 5 mounted on the body 2, and FIG. 9 is an enlarged sectional view of the press-fitted portion of the support shaft 3.

At this time, both opposing side wall portions 7 and 8 may be slightly inwardly inclined so that the supporting shaft 3 is firmly held by the opposing side wall portions 7 and 8. That is, the substrate 5
When A is bent into a substantially U-shape, both opposing side wall portions 7 and 8 are formed so as to be inclined slightly inward as shown in FIG. As a result, the support shaft 3 is attached to the opposite side wall portions 7, 8
In the state of being installed in between, the opposing side wall portions 7 and 8 firmly sandwich the support shaft 3 from both sides, and the support shaft 3 can be held more reliably in the rotation-prevented state.

According to the rocker arm 1 and the method of manufacturing the rocker arm 1 configured as described above, both ends of the support shaft 3 are press-fitted into the bearing recess 11 from the inside of the body 2 to place the support shaft 3 between the opposing side wall portions 7 and 8. Since it is installed, the caulking for preventing the support shaft 3 from coming off is unnecessary. Therefore, it is not necessary to form uncured portions for caulking on both ends of the support shaft 3, the entire support shaft 3 can be subjected to thermosetting treatment, and is not damaged during the manufacturing process or transportation,
It can be manufactured easily and inexpensively, and the surface hardness can be easily controlled to improve the quality.

Since both ends of the support shaft 3 are press-fitted into the bearing recesses 11 in a state where the roller 4 is rotatably mounted via the needle roller 5, the support shaft 3 and the roller 4 can be mounted on the body 2 at the same time. The manufacturing process can be simplified. Moreover, there is no need to worry about the needle roller 5 interposing between the support shaft 3 and the roller 4 being separated when assembled, and it is not necessary to separately hold the needle roller 5 with a holding plug, and the manufacturing process is further improved. Can be simplified.

Further, the support shaft 3 has opposite side wall portions 7,
Since the bearing recess 11 formed on the inner surface of the support 8 is press-fitted and installed, the end surface of the support shaft 3 is not exposed on the outer surface of the opposing side wall portions 7 and 8, and the appearance is good.

As shown in FIG. 11, the bearing recesses 11 of the opposing side wall portions 7 and 8 have a large diameter portion 11a and a small diameter portion 11b.
Is formed by a through hole made of, and circular projections 3a that can be fitted into the small diameter portion 11b are formed at both ends of the support shaft 3. The circular projection 3a is press-fitted into the small diameter portion 11b and the support shaft 3 is formed. Both ends of the body may be press-fitted into the large diameter portion 11a. With this configuration, the contact area (press-fitting margin) between the support shaft 3 and the opposing side wall portions 7 and 8 is increased, and the supporting force of the support shaft 3 by the body 2 is improved.

12 and 13 show a modified example of the rocker arm of the present invention. The same parts as those in the example shown in FIGS. 1 to 9 are designated by the same reference numerals, and the description thereof will be omitted.

This example is characterized in that anti-rotation convex portions 14 serving as anti-rotation portions are formed at both ends of the support shaft 3.

The anti-rotation protrusions 14 are integrally formed on both ends of the support shaft 3 so as to extend in one radial direction. Further, in the bearing recesses 11 of the opposite side wall portions 7 and 8, there are formed anti-rotation recesses 15 serving as fitting portions into which the anti-rotation protrusions 14 can be fitted.

The support shaft 3 is formed by elastically deforming approximately the middle of the opposing side wall portions 7 and 8 in the longitudinal direction so that the anti-rotation protrusion 14 is formed.
Is fitted into the rotation preventing recess 15, and both ends thereof are press-fitted into the bearing recess 11 so as to be installed between the opposed side wall portions 7 and 8.

As a result, the rotation of the support shaft 3 can be prevented more reliably. It should be noted that it is also possible to form anti-rotation recesses that serve as anti-rotation parts at both ends of the support shaft 3 and to form anti-rotation projections that serve as fitting parts that can be fitted into the anti-rotation recesses in the bearing recess 11. Good.

Further, as shown in FIG. 14, a detent recess 15 may be formed in the bearing recess 11 of each of the opposed side walls 7 and 8 so as to penetrate the opposed side walls 7 and 8. That is, since the anti-rotation recess 15 is formed so as to penetrate through the opposing side wall portions 7 and 8, the bearing recess 11 can be formed deeper by that amount, and the contact area between the spindle 3 and the opposing side wall portions 7 and 8 (press-fitting margin). ) Is increased, and the supporting force of the support shaft 3 by the body 2 is improved.

The valve contact portion 10 may be formed separately from the body 2 and fixed to the body 2 by welding or the like.

Further, in order to securely hold the support shaft 3, as shown in FIG. 10, the opposite side wall portions 7 and 8 are slightly inwardly inclined, but the present invention is not limited to this, and the support shaft 3 may be used, for example. A structure in which pawls are formed on the outer peripheral surfaces of both ends of the shaft 3, and when the both ends of the support shaft 3 are press-fitted into the bearing recess 11, the pawls are caught on the inner surface of the bearing recess 11 to improve the retention of the support shaft 3. May be

Alternatively, the roller 4 may be brought into sliding contact with the support shaft 3 without using the needle roller 5. That is,
The roller 4 may be directly fitted onto the support shaft 3 by a clearance fit, or may be fitted via a slide bearing.

Further, the body 2 may be a cast product made of iron-based metal or a light alloy such as aluminum by a lost wax method or a die casting method.

[0056]

According to the rocker arm and the method of manufacturing the same of the present invention, there is an effect that the support shaft is not damaged, the manufacturing is simple and inexpensive, and the quality and appearance are improved.

[Brief description of drawings]

FIG. 1 is a side view showing a rocker arm according to an embodiment of the present invention.

FIG. 2 is a development view of the body of the rocker arm according to the embodiment of the present invention.

3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a plan view of a body of a rocker arm according to an exemplary embodiment of the present invention.

FIG. 5 is a view on arrow V in FIG.

FIG. 6 is a perspective view showing an assembling operation of the support shaft of the rocker arm according to the embodiment of the present invention.

FIG. 7 is a side view showing an assembling operation of the support shaft of the rocker arm according to the embodiment of the present invention.

FIG. 8 is a plan view of a rocker arm according to an embodiment of the present invention.

FIG. 9 is a partially enlarged sectional view of a rocker arm according to an embodiment of the present invention.

FIG. 10 is a front view of the rocker arm according to the embodiment of the present invention.

FIG. 11 is a partial enlarged cross-sectional view of a modified example of the rocker arm according to the embodiment of the present invention.

FIG. 12 is a side view showing the work of incorporating the support shaft of the rocker arm according to the modified example of the present invention.

FIG. 13 is a plan view of a rocker arm according to a modified example of the present invention.

FIG. 14 is a plan view of a rocker arm according to still another modification of the present invention.

FIG. 15 is a side view showing a rocker arm according to a conventional example.

16 is a sectional view taken along line XVI-XVI of FIG.

[Explanation of symbols]

1 rocker arm 2 torso 3 spindles 4 roller 5 needle rollers 7,8 Opposing side wall 9 Pivot part 10 Valve contact part 11 Bearing recess 14 Anti-rotation convex part (anti-rotation part) 15 Anti-rotation recess (fitting part)

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3G016 AA06 AA19 BA18 BA49 BB22                       CA05 CA07 CA10 CA12 CA14                       CA15 CA21 CA25 CA34 CA35                       CA44 CA52 EA01 FA01 FA06                       FA16 FA19 FA29 FA37 GA01

Claims (4)

[Claims] 1. A body comprising a pair of opposing side wall portions arranged substantially parallel to each other, and a pivot portion and a valve abutting portion provided at both longitudinal ends of the opposing side wall portions, respectively. The support shaft is provided between the opposing side wall parts, and includes a support shaft having at least an entire circumferential surface subjected to quench hardening treatment; and a roller rotatably mounted on the support shaft between the opposing side wall parts. The portion is provided with bearing recesses coaxially on the inner surfaces facing each other at approximately the middle in the longitudinal direction, and the support shaft is installed between the opposite side wall portions with both ends thereof press-fitted into the bearing recesses. A rocker arm that is characterized by 2. The rocker arm according to claim 1, wherein rotation preventing portions are provided at both ends of the support shaft, and fitting portions into which the rotation preventing portion can be fitted are formed in the bearing recess. A rocker arm, characterized in that a stopper portion is fitted into the fitting portion, and both ends of the spindle are press-fitted into the bearing recesses. 3. A pair of opposed side walls arranged substantially parallel to each other, and a pivot part and a valve contact part provided respectively at both ends in the longitudinal direction of the opposed side wall parts. A roller body is rotatably formed in a state in which a body having a bearing recess is coaxially formed on inner surfaces facing each other at approximately the middle in the longitudinal direction of the portion, and the approximately middle portions in the longitudinal direction of the opposed side wall portions are elastically deformed outward. A method for manufacturing a rocker arm, comprising press-fitting both ends of a support shaft, which is externally applied and has at least an entire circumferential surface subjected to quenching and hardening treatment, into the bearing recesses, and bridges the support shaft between the opposite side wall parts. 4. The method for manufacturing a rocker arm according to claim 3, wherein rotation preventing portions are provided at both ends of the support shaft, and fitting portions into which the rotation preventing portion can be fitted are formed in the bearing recess. A method of manufacturing a rocker arm, characterized in that the detent portion is fitted into the fitting portion, and both ends of the support shaft are press-fitted into the bearing recesses.