JP2805409B2 - Sheet metal roller rocker arm and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller rocker arm for opening and closing a valve provided on a cylinder head in response to a sliding operation by a cam, and more particularly to a roller rocker arm formed of sheet metal and a method of manufacturing the same. .

[0002]

2. Description of the Related Art As is well known, a roller rocker arm used for a valve operating mechanism is generally manufactured integrally with lost wax, hot casting, or the like in consideration of durability in consideration of durability. There was no problem, but the cost was very high.

[0003] Therefore, a part of a roller rocker arm manufactured by press-molding a sheet metal material has been mass-produced. As shown in FIG. 21, in the shape punching step shown in FIG. 21A, this rocker arm is formed by punching a sheet metal material into a developed shape of a rocker arm main body having a roller mounting portion in the center and a portion bulging outward in the vicinity thereof. Then, in a bending step shown in FIG. 21 (b), a side plate is formed by bending the cross-section into a downward U-shape, and one end thereof is narrowed to form a valve fitting portion, thereby forming a roller insertion portion. To do so, as shown in FIG. 21 (c), one end of the narrowed side plate is pressed downward from above, and both side walls of the opening are symmetrically pressed upward against the one end to deform the side wall. To form a roller insertion part,
In the drawing step shown in FIG. 21D, the other end opposite to the one end where the valve fitting portion is formed is drawn into a shape corresponding to the pivot portion of the lash adjuster to form a pivot engagement portion, and further, the roller is inserted. A roller support portion is provided by making a hole in the outer wall of the portion, and then the roller is fixed to the support portion by a shaft.

[0004]

However, in the roller rocker arm formed as described above, the valve fitting portion is formed integrally with the valve rocker arm toward the valve (downward).
Because the rocker arm body is molded in a U-shaped cross section,
The rocker arm body must be pressed up and down to form the valve fitting portion and the roller insertion portion, and the material is closer to cold forging than sheet metal forming. Therefore, it is difficult to secure the molding accuracy of the valve fitting portion and the roller insertion portion. Further, there is a problem that the plate thickness of the rocker arm body becomes thin due to complicated forming for cold forging, and the rigidity of the rocker arm is not high.

[0005]

Therefore, in the present invention, one is connected by a connecting portion and the other is cut out and opened, and the cross section is bent upward in a U-shape with the width of the connecting portion. A main body having a pair of side walls on which a roller supporting portion is formed, a pivot engaging portion formed on the connecting portion, and a roller member positioned in the opening and supported by a shaft on the roller supporting portion; A sheet metal roller rocker arm composed of the main body fixed to the end of the opening by integral means and a valve engaging member formed separately was manufactured by a method including the following steps.

[0006] The manufacturing method according to the present invention comprises a shape punching step of forming a connecting portion on one side of the plate material and forming a connecting portion on the other side, and forming a roller supporting portion on both outer sides of the notch. A bending step of bending the roller support portion upward so that the roller support portion is coaxially arranged to form a pair of side walls having a U-shaped cross section, and pressing the joint portion to form a pivot engagement portion. A molding step and a joining step of joining a separately formed valve engaging member to an end of an opening formed between the side walls by the notch.

[0007]

A rocker arm body in an unfolded state in which a notch is formed at one end and a connecting portion is provided at the other end, and a hole serving as a roller support is formed around the notch.
In the bending step, the roller support portion was bent upward so as to be coaxially arranged to have a U-shaped cross section, and the valve fitting portion was formed separately from the main body and attached later, so that the side plate was The degree of design freedom (the degree of freedom of the main body deployment shape during the punching process) is increased, and the valve insertion fits with the roller insertion part in the main body bending process and the joining process without narrowing down the side plate or pressing up and down as in the past. A part is formed.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

First Embodiment FIG. 20 shows a part of a cylinder head 1. The cylinder head 1 has a moving part composed of a valve 2, a valve spring 3, a lash adjuster 4, a cam shaft 5, and a rocker arm 6. A valve mechanism is provided. The rocker arm 6 has a roller rocker arm 6 having a roller 7.
The roller 7 is in contact with the cam 8 on the camshaft 5. The pivot portion 4a of the lash adjuster 4 is engaged with one end of the rocker arm 6, and the stem 2a of the valve 2 is fitted to the other end. In the valve mechanism configured as described above, the rocker arm 6 presses the upper end of the valve stem 2 a by the rotation of the camshaft 5, and the valve 2 projects into the combustion chamber 9 against the valve spring 4. The above-mentioned roller rocker arm 6, which opens and closes each of the intake and exhaust ports 10 and 10 'at a predetermined timing, is made of sheet metal, and includes a rocker arm body 11, a roller 7, and a valve engaging member 14, as shown in FIGS. It is configured. The rocker arm body 11 has an upward U-shaped cross section, and one end 11 a thereof is connected by a connecting portion 12. The lash adjuster 4 (FIG. 2)
The engaging portion 12a with which the pivot portion 4a of (0) is engaged is formed by drawing. The engaging portion 12a has a cross-sectional shape similar to a mirror cake as shown in FIGS.

The other end 11b of the rocker arm body 11 is cut out to the vicinity of the pivot engaging portion 12a, and side walls 11c are formed on both sides of the notch by bending. A hole 13 is formed in each of the side walls 11c as a roller supporting portion, and a valve engaging member 14 formed as a member separate from the rocker arm body 11 is provided between the side walls 11c corresponding to the ends of the notches. The lower surface is fixed by means such as welding (see FIGS. 2 and 5). In addition, the code | symbol W shows a welding part.

The valve engaging member 14 is made of a wear resistant material such as high Cr steel or ceramic in consideration of wear resistance. A groove 14 a is formed on the lower surface of the engaging member 14 toward the longitudinal direction of the rocker arm main body 11. The width of the groove 14a is determined by the width of the valve stem 2 used.
In addition to being finished to approximately the same diameter as the outer diameter a, as shown in FIG. 3, the inner upper surface 14b is formed into a curved surface in consideration of the state of contact with the valve stem. That is, the groove 14a serves as a valve fitting portion.

On the other hand, the roller 7 is rotatably supported by a shaft 15 between the side walls 11c located between the valve engaging member 14 and the pivot engaging portion 12a, ie, between the roller inserting portions 11d. As shown in FIG. 3, the roller 7 uses a roller bearing to reduce uneven wear and noise of the cam 8 and the bearing.

The manufacturing process of the roller rocker arm 6 configured as described above will be described below with reference to FIG.

First, in the punching step shown in FIG. 6 (a), one is cut out and the other is connected, holes 13 are located on both sides of the notch, and the periphery of each hole 13 is in the notch side. The sheet metal material is punched into a substantially U-shaped planar shape that bulges outward, and the rocker arm main body 11 in an expanded shape is formed. At this time, the maximum width of the notch is about the largest roller width among the rollers 7 to be used.

Next, in the bending step shown in FIG. 6B, the expanded rocker arm pair is formed so that the holes 13 formed on both sides of the notch in the step (a) are coaxial with the notch. 11 is bent at the notch width to form a U-shaped cross section, and side walls 11c are formed on both sides of the notch.

Next, in the drawing step shown in FIG.
1c is connected to the rocker arm body 11
To the upper part (opening of a U-shape) of the connecting portion 12
The pivot engagement portion 12a is formed so as to project therefrom, and in the joining step shown in FIG. 6D, the previously formed valve engagement member 14 is fixed between the side walls 11c located at the ends of the notches. Then, the roller 7 is inserted into the roller insertion portion 11d from above the rocker arm main body 11, and is mounted on the side plate 11c with a shaft inserted into the hole 13.

When the width of the roller 7 to be mounted is smaller than the width of the connecting portion 12, the width of the roller fitting portion 11d is reduced by bending the side wall 11c up to the notch shown in FIG. Therefore, it is possible to easily cope with the rollers 7 'having different widths.

In this embodiment, the valve engaging member 14 is welded and fixed on the lower surface side. However, as shown in FIG. 7, the valve engaging member 14 is welded and fixed on the upper surface side, or as shown in FIG. A portion of the side surface 14c is formed so as to protrude toward the side wall 11c, and the protruding portion is thickly welded to a lower portion of the side wall 11c, so that the engagement member 14 can be more firmly fixed. The hole 13 may be formed after the joining step shown in FIG.

Second Embodiment A side plate 11c of the first embodiment is modified.
9 to 11. The edge X of the side wall 11c located at the other end 11b of the rocker arm body shown in FIG.
Are provided respectively. This groove 16 is formed at the time of the punching step shown in FIG. 6A, and the groove 16 is engaged with a valve engaging member 14 'having no groove 14a, which is a valve fitting portion. The valve engaging member 14 'has a width up to the outer surface of the side wall 11c, and the lower surface 14'c is formed in a curved shape, and is made of a wear-resistant material.

A portion a of the side wall 11c located below the groove 16 is narrowed down, and the valve engaging member 14 'is fixed by welding the upper surface side inside the side wall 11c and the lower surface 14'c side by welding outside the partial a. Have been. In this manner, the valve engaging portion 14'a is formed by the valve engaging member 14 'and the part a of the side wall. Further, in the roller rocker arm 6 shown in FIG. 10, the end Y of the side wall 11c is narrowed down as a whole, and the valve engaging member 14 'is provided between the narrowed side wall 11c.
Is fixed, and a valve fitting portion 14'a is formed by the engaging member 14 'and the side wall 11c.

Further, in the roller rocker arm 6 shown in FIG. 11, the end portion Y is bent at a substantially right angle between the side walls 11c, and the bent end portion Y is formed with a groove 14a serving as a valve fitting portion. The valve engaging member 14 is fixed by welding. By slightly deforming the side plate 11c in this way, the method of fixing the valve engaging member is widened and the width of the valve fitting portion can be adjusted.

Third Embodiment A third embodiment of the present invention will be described with reference to FIGS. In the third embodiment, the valve engaging member is formed in a shaft or bolt shape and mounted on the side wall 11c.

In the roller rocker arm 6 shown in FIG.
From the shaft 15 supporting the roller 7, in FIG.
A through hole 17 is provided in each side plate 11c located on the left side. The through holes 17 are formed at the time of the rocker arm main body punching step shown in FIG. A shaft 18 shown in FIG. 15 is supported in the through hole 17 as a valve engaging member. This shaft 18 has a through hole 17
The two ends 18a supported by are formed in a columnar shape, and a portion located between the side walls 11c is a half-moon shape, and a groove 14a serving as a valve fitting portion is formed in the circular arc portion 18b. Then, by caulking the both ends 18a, it is fixed to the support holes 17 in the side wall 11c.

FIG. 13 shows the roller rocker arm 6 in which the shaft-shaped valve engaging member 19 is fixed to the through hole 17 by the snap ring 20. As shown in FIG. 16, the valve engaging member 19 fixed to the rocker arm 6 is a shaft having a cylindrical head 19a at one end and a circumferential groove 19b cut at the other end. The snap ring 20 is fitted so that the movement in the axial direction is restricted.
The portion of the shaft 19 located between the side walls 11c is
Similar to the shaft 18 shown in FIG. 15, the upper part is shaped like a half moon with a flat shape, and the arc portion 19c is provided with a groove 14a.

The through hole 17 of the rocker arm 6 shown in FIG.
The bolt-shaped valve engaging member 21 shown in FIG. One end 21a of the engagement member 21 is formed to have a small diameter and is threaded, and
Similarly to 9, a groove 14a is provided in the semicircular arc portion 21b, and is fixed to the side plate 11c by tightening the nut 22.

By forming the valve engaging member in the shape of a shaft or a bolt, the operation of fixing the valve engaging member to the side wall 11c can be simplified. Further, in the case of a type fixed by a nut or a ring, the axial position of the groove 14a, which is the valve fitting portion, can be adjusted by adjusting the ring mounting position or the tightening of the nut.

The roller rocker arm 6 shown in FIG. 18 is provided with a valve engaging member 23 having a clearance adjusting mechanism with the valve stem 2a (FIG. 20). As shown in FIG. 19, the engaging member 23 is a cube having a height higher than a side wall 11c having a groove 14a formed in a lower surface 23a.
It is fixed by welding between 1c. A screw hole 24 is formed in the upper surface 23b of the engagement member 23 toward the groove 14a formed in the lower surface 23a.
Are drilled. A screw rod 25 having a slit 26 formed at one end 25a and a curved end at the other end 25b is screwed into the groove 14a. Is screwed.

That is, the clearance between the valve stem 2a and the screw rod 25 in the vertical direction can be adjusted by loosening the lock nut 27 and turning the screw rod 25 to adjust the amount of protrusion of the screw 25 into the groove 14a. Become.

As described above, the rocker arm body 1
1 has a U-shaped cross section, a part corresponding to the bottom on one side thereof is cut away, and the side wall 11c is connected only by the connecting portion 12, so that the roller insertion portion is formed by bending the inside of the side plate. The width can be set freely. In addition, since the valve engaging member formed separately from the main body is provided with a groove as the valve fitting portion, the fitting portion can be adjusted by changing the groove width.
Further, when the rigidity of the valve fitting portion is to be increased, it is possible to cope by changing only the valve engaging member to a wear-resistant material, so that the cost of the rocker arm can be reduced.

[0030]

According to the present invention, the bending of the main body is reduced, so that there is no shortage of the thickness due to the bending, and the rigidity of the sheet metal roller rocker arm can be increased.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a roller rocker arm according to a first embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a sectional view of the roller rocker arm shown in FIG. 1;

FIG. 4 is a sectional view taken along the line AA of FIG. 2 ;

FIG. 5 is a bottom view showing a modification of the first embodiment.

FIG. 6 is a schematic view showing a forming process of the roller rocker arm of the first embodiment.

FIG. 7 is a side view showing a modified example of a welding portion of the valve engaging member in the first embodiment.

FIG. 8A is a side view showing a modified example of the roller rocker arm of the first embodiment, and FIG. 8B is a front view of the roller rocker arm.

FIG. 9A is a side view showing a roller rocker arm according to a second embodiment of the present invention, and FIG. 9B is a front view of the roller rocker arm.

FIG. 10A is a side view showing a modified example of the roller rocker arm of the second embodiment, and FIG. 10B is a front view of the roller rocker arm.

11A is a side view showing a modified example of the roller rocker arm according to the second embodiment, and FIG. 11B is a front view of the roller rocker arm.

FIG. 12A is a side view showing a roller rocker arm according to a third embodiment of the present invention, and FIG. 12B is a front view of the roller rocker arm.

FIG. 13A is a side view showing a modified example of the roller rocker arm of the third embodiment, and FIG. 13B is a front view of the roller rocker arm.

FIG. 14A is a side view showing a modified example of the roller rocker arm of the third embodiment, and FIG. 14B is a front view of the roller rocker arm.

FIG. 15 is a perspective view showing a valve engaging member in FIG.

FIG. 16 is a perspective view showing a valve engaging member in FIG.

FIG. 17 is a perspective view showing a valve engaging member in FIG.

FIG. 18A is a side view showing a modified example of the roller rocker arm of the third embodiment, and FIG. 18B is a front view of the roller rocker arm.

FIG. 19 is a perspective view showing the structure of the valve engaging member in FIG.

FIG. 20 is a schematic view showing a valve operating mechanism using a conventional sheet metal roller rocker arm.

FIG. 21 is a schematic view showing a forming process of a conventional sheet metal roller rocker arm.

[Explanation of symbols]

 Reference Signs List 6 Roller rocker arm 7, 7 'Roller member 11 Rocker arm main body 11c Side wall 11d Roller insertion part 12 Connecting part 12a Pivot engagement part 13 Roller support part 14 Valve engagement member 15 shaft

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takao Ichimura 5-33-8 Shiba, Minato-ku, Tokyo / Inside Mitsubishi Motors Corporation (72) Inventor Hirokazu Komai 5-33 Shiba, Minato-ku, Tokyo No. 8, Mitsubishi Motors Corporation (72) Inventor Kenji Takahashi 3-5-8 Minamisenba, Chuo-ku, Osaka City, Osaka Prefecture, Koyo Seiko Co., Ltd. (56) References JP-A-3-172506 (JP, A) JP-A-63-272903 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F01L 1/18

Claims (2)

(57) [Claims] 1. A pair of roller supporting portions, one of which is connected by a connecting portion and the other of which is cut out and opened to form a roller supporting portion having a cross section bent upward in a U-shape with the width of the connecting portion. A main body having a side wall, a pivot engaging part formed in the connecting part, a valve engaging member formed separately from the main body fixed to an end of the opening by integral means, and the side wall; A sheet metal roller rocker arm comprising: a roller insertion portion formed by the valve engagement member and the connection portion; and a roller member supported by the roller support portion via a shaft and disposed in the roller insertion portion. 2. A shape punching step in which one of the plate materials is notched and a connecting portion is formed on the other side, and a roller supporting portion is formed on both outer sides of the notch; and the roller supporting portion is coaxial with the connecting portion. A bending step of forming the pair of side walls having a U-shaped cross-section by bending the roller support portion upward so as to be disposed at a position; a squeezing forming step of forming a pivot engagement portion at the connection portion; A joining step of joining a separately formed valve engagement member to an end of the opening formed between the side walls by the notch, and a joining step of joining the sheet metal roller rocker arm.