JP2004108375A - Rocker arm - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control variation of dimensions for each product by accurately performing relative positioning of two members composing a frame in attaching the two members. <P>SOLUTION: In a second member 7 fixed by welding on another end side in a longitudinal direction of a pair of wall parts 61, 61 of a first member 6, projection parts 72, 72 are provided on end parts 71, 71 corresponding to another end side in the longitudinal direction of the pair of the wall parts 61, 61 of the first member 6, and end surfaces 73, 73 of the projection parts 72, 72 are formed flat. In joining two members 6, 7, the second member 7 can be stably positioned in relation to the first member 6 in an appropriate attitude and the positioning can be done accurately by using the flat end surfaces 73, 73 of the second member 7 as a positioning reference surface in positioning the second member 7 in relation of the first member 6. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a rocker arm that opens and closes a valve provided on a cylinder head of an engine with rotation of a cam in an engine, and more particularly, to an improvement on a valve engagement side of a press frame.

FIGS. 13 to 16 show an example of a conventional rocker arm of this type (see Patent Document 1). 13 is a longitudinal side view of the rocker arm, FIG. 14 is an exploded perspective view of the rocker arm, FIG. 15 is a top view of a main part of the rocker arm, and FIG. 16 is a manufacturing process diagram of the second member. The rocker arm 40 in the illustrated example includes a frame 41 formed by press-forming a metal plate punched into a required shape, and a roller 42.

The frame 41 has a two-piece structure having a substantially U-shaped cross section and including two members 43 and 44. The first member 43 is connected to a pair of rising wall portions 45, 45 that are disposed substantially parallel to each other and is connected to each other at one longitudinal end of the pair of wall portions 45, in a bridging manner and substantially at the center. And a connecting portion 46 in which a hemispherical pivot engaging portion 47 is provided. The pivot engagement portion 47 is provided with an oil hole (reference numeral omitted) for ejecting lubricating oil toward the roller 42 side. The second member 44 is joined and fixed between the pair of wall portions 45, 45 at the other ends in the longitudinal direction in a cross-linking manner therebetween. The second member 44 is curved and formed along the longitudinal direction of the wall portions 45, 45 to form the valve. It is an engagement portion.

The roller 42 is rotatably supported via a shaft 48 and a needle roller bearing 49 extending between the holes 50 of the pair of wall portions 45, 45, and is disposed in the through hole 51 of the frame 41. .

The rocker arm 40 swings up and down about a pivot engaging portion 47 with which the pivot P of the lash adjuster engages as the roller 42 is pushed by the rotation of the cam C linked to the crankshaft, and the second member The valve stem V engaged with 44 is moved up and down along a valve guide (not shown).

An example of manufacturing the frame 41 will be described. First, the first member 43 is formed by punching a single metal plate material into, for example, a substantially U-shape in plan view and bending the two protruding portions so as to face each other to form a pair of wall portions 45, 45. Is obtained by drawing a hemispherical pivot engaging portion 47 at the connecting portion (connecting portion 46). One of the second member 44, providing a single rectangular metal plate B ₁ shown in FIG. 16 (a), which imaginary line X, and by bending the cross-section substantially reversed U-shape along the X 16 ( a shape B ₂ as shown in b), an a side view substantially fan shape to indicate that the top plate portion B ₃ in FIG. 16 (c) by curving along the longitudinal direction. Then, the two side wall portions B ₄ , B ₄ of the second member 44 are joined and fixed to the free end side of the wall portion (see FIG. 14) of the completed first member 43 by welding or the like. .
JP-A-5-179907

The rocker arm 40 having the two-piece frame 41 as in the above-described conventional example has an advantage that the manufacture is easier than the rocker arm having the one-piece frame. It is pointed out that it is difficult to position and attach the 44 with high precision.

That is, when the second member 44 is attached to the wall portions 45, the distance from the longitudinal center of the second member 44 to the center of the connecting portion 46 of the first member 43 is adjusted to a required size. Like that. At this time, by applying one longitudinal end of the second member 44 to the first member 43 against the positioning jig (see FIG. 5), the relative position between the first member 43 and the second member 44 is increased. Conventionally, the positioning is performed. Conventionally, since the second member 44 is formed into a substantially sector shape in a side view, both ends in the longitudinal direction of the second member 44 are plastically deformed into an irregular shape. When positioning the second member 44 with the second member 44, the posture of the second member 44 tends to be unstable. This makes it difficult to perform the above-described positioning with high precision. As a result, the distance from the center in the longitudinal direction of the second member 44 to the center of the pivot engagement portion 47 of the connecting portion 46 of the first member 43 is reduced. It is easy to vary.

In view of such circumstances, the present invention makes it possible to perform relative positioning of two members with high accuracy when mounting two members constituting a frame, and to suppress dimensional variations of individual products. That is the task.

The present invention is a rocker arm that opens and closes a valve provided on a cylinder head with the rotation of a cam, and includes a roller to which the cam comes into contact, and a press frame that rotatably supports the roller. The frame includes a pair of walls that are disposed substantially parallel to each other and that are rotatably mounted at the center in the longitudinal direction, and a pivot member provided to connect one end in the longitudinal direction of the pair of walls in a cross-linked manner. A mating portion, and a valve engaging portion provided to connect the other ends of the pair of wall portions in the longitudinal direction in a cross-linked manner, wherein the valve engaging portion is curved along the longitudinal direction of the wall portion. It is also curved along the width direction of the wall.

The present invention is a rocker arm that opens and closes a valve provided on a cylinder head with the rotation of a cam, and includes a roller to which the cam comes into contact, and a press frame that rotatably supports the roller. A frame having a two-piece structure composed of two members, a first member of the two members being a pair of wall portions disposed substantially parallel and opposed to each other so as to rotatably support the roller in the middle in the longitudinal direction. A connecting portion provided at one longitudinal end of the pair of wall portions and connected in a cross-linking manner therebetween and provided with a pivot engaging portion, and a second member of the two members is The other end of the pair of walls of the first member in the longitudinal direction is joined and fixed therebetween in a cross-linking manner to form a valve engaging portion, and the second member of the two members is the second member. One member of a pair of walls The other end in the longitudinal direction is joined and fixed in a cross-linking manner therebetween to form a valve engaging portion, wherein the second member is curved along the longitudinal direction of the wall, and Are also curved along the width direction.

The second member is formed to have a substantially inverted U-shaped cross section, and a pair of opposed wall portions of the second member is joined to the pair of wall portions to form the second member. The top plate portion may be arranged in the height direction of the pair of wall portions.

In the above-described configuration, since the flat surface which is the reference surface when the second member is attached is formed at the end corresponding to the other end in the longitudinal direction of the pair of walls in the second member, the two members are formed. When the second member is positioned with respect to the first member in joining the two members, if the flat surface of the end portion of the second member is used as a reference surface, the second member is placed in an appropriate posture with respect to the first member. Since the positioning can be performed stably, the positioning can be performed with high accuracy.

As described above, in the present invention, the second member can be stably positioned in an appropriate posture with respect to the first member, and the positioning can be performed with high accuracy. The distance from the center of the pivot engagement portion to the predetermined portion of the second member can be accurately controlled, and a high-quality rocker arm can be provided that minimizes variations among products.

Hereinafter, the details of the present invention will be described based on the embodiment shown in FIGS. 1 to 6 relate to a first embodiment of the present invention. FIG. 1 is a longitudinal side view of a rocker arm, FIG. 2 is an exploded perspective view of the rocker arm, FIG. 3 is a top view of the rocker arm, and FIG. FIG. 5 is a perspective side view of a single unit, FIG. 5 is a longitudinal sectional side view for explaining a mounting state of a second member, and FIG.

で は In this embodiment, an example in which the basic configuration is the same as the conventional example is described. That is, the rocker arm 1 in the illustrated example has a structure in which the roller 3 is rotatably mounted on the press-made frame 2 via the shaft 4 and the needle roller bearing 5. Note that the needle roller bearing 5 may be omitted.

The frame 2 has a two-piece structure composed of two members 6 and 7 having a substantially U-shaped cross section. Examples of the material of the frame 2 include chromium molybdenum steel such as JIS SCM415 and 420, JIS SCr420 and SAE 5120 and the like. Case-hardened steel or JIS-standard SPC cold-rolled steel sheet is preferably used. The first member 6 includes a pair of rising wall portions 61, 61 arranged opposite to each other, and a pair of wall portions 61, which are connected to each other at one longitudinal end of the pair of wall portions 61, in a bridging manner therebetween. , 61 side and a connecting portion 62 provided with a hemispherical pivot engaging portion 63 so as to leave a flat portion of a required width D. The pivot engagement portion 63 is provided with an oil hole (reference number omitted) for ejecting lubricating oil toward the roller 3. The second member 7 is joined and fixed between the pair of wall portions 61, 61 at the other end sides in the longitudinal direction in a cross-linking manner therebetween. It is an engagement portion. The top plate portion 74 of the second member 7 is slightly curved also in the width direction, so that the sliding contact resistance with the valve stem V is reduced.

The roller 3 is rotatably supported via a shaft 4 and a needle roller bearing 5 extending between holes 64, 64 of the pair of wall portions 61, 61, and is disposed in the through hole 8 of the frame 2. . The roller 3 is formed of a steel material (for example, SUJ-2 of JIS standard) or a ceramic mainly composed of silicon nitride.

The rocker arm 1 swings up and down with the pivot 3 being pushed by the roller 3 with the rotation of the cam C interlocking with the crankshaft, with the pivot engaging portion 63 with which the pivot P of the lash adjuster engages as a fulcrum. The valve stem V that engages with 7 is moved up and down along a valve guide (not shown).

In the present embodiment, the configuration different from the conventional example is mainly the second member 7. That is, as shown in FIG. 4, the second member 7 has convex portions 72, 72 in the widthwise middle of both end portions 71, 71 corresponding to both longitudinal ends of the pair of wall portions 61, 61 of the first member 6. Each one is provided, and each end face 73 of this convex part 72 is formed flat. Specifically, the second member 7 of substantially side view sector in a state in position as shown in FIG. 6 (d), the center of gravity G of the end face 73, 73 in the longitudinal direction of both ends in its longitudinal center O ₂ It is formed on a flat surface that is substantially parallel to the line along.

Next, an example of manufacturing the frame 2 will be described. First, the first member 6 is formed by punching a single metal plate into, for example, a substantially U-shape in plan view and bending the two protruding portions so as to face each other to form a pair of wall portions 61, 61. Is obtained by drawing a hemispherical pivot engaging portion 63 at the connecting portion (connecting portion 62).

One of the second member 7, providing a metal plate A ₁ of one square as shown in FIG. 6 (a), which imaginary line X, and by bending cross section substantially reversed U-shape along the X a shape a ₂ as shown in FIG. 6 (b), and side view substantially fan shape as shown in FIG. 6 (c) by curving along the top plate portion a _{3 (74)} in the longitudinal direction. If the projections A ₄ (72, 72) are substantially fan-shaped as viewed from the side, the respective end faces A ₅ (73, 73) of the projections A ₄ (72, 72) are plastically deformed into an irregular shape. ), And each end face A ₅ ( ₅ ) of the convex portion A ₄ (72, 72) along a line Y, Y substantially parallel to a line along the center of gravity G at the center O ₂ in the longitudinal direction. by cutting 73), and these end faces _a 5 a (73, 73) to the substantially flat second member 7 is completed.

Thereafter, the two wall portions 75, 75 of the second member 7 are joined and fixed to the free end sides of the wall portions 61, 61 of the first member 6 by welding or the like. Specifically, in the longitudinal direction while the flat state of the end face 73 against wanted relative to the positioning jig 9 of the second member 7, as shown in FIG. 5, the longitudinal center O ₂ of the second member 7 from the distance L to the center O ₁ of the pivot engaging portion 63 of the flat portion 62 of the first member 6 and positioned adjusted to the required dimensions required, by joining secured thereto by welding or the like both Frame 2 is completed.

The frame 2 obtained in this way is subjected to a quench hardening process, and after shaping the entire surface of the frame 2 by barrel processing or the like, the shaft 4 inserted into the holes 64, 64 of the pair of wall portions 61, 61. The roller 3 is mounted between the pair of wall portions 61, 61 via the intermediate member to complete the rocker arm.

By the way, in the above-described positioning step, the flat end face 73 of the convex portion 72 of the second member 7 is used as a reference surface when positioning the second member 7 with respect to the first member 6. The second member 7 can be stably arranged in an appropriate posture, and as a result, the distance L can be managed with high accuracy. When adjusting the distance L, it is preferable that a ball having the same diameter as the pivot P of the lash adjuster is applied to the pivot engaging portion 63, and the center of the ball is set as the center of the pivot engaging portion 63. By doing so, it becomes easier to set the above-mentioned interval L more appropriately regardless of the magnitude of the shape error of the pivot engagement portion 63.

7 to 9 relate to a second embodiment of the present invention, FIG. 7 is an exploded perspective view of a rocker arm, FIG. 8 is a top view of the rocker arm, and FIG. 9 is a perspective view of a second member alone. In this embodiment, concave portions 72A, 72A are provided at both ends 71, 71 in the longitudinal direction of the second member 7 instead of the convex portions 72, 72 of the first embodiment. The end surfaces 73A, 73A of the concave portions 72A, 72A are also formed as flat reference surfaces, as in the above-described embodiment. Other configurations are the same as those in the above embodiment. If end portions 73A, 73A serving as flat reference surfaces are provided in concave portions 72A, 72A as described above, end surfaces 73A, 73A may be damaged even when the second member 7 is handled alone even if it collides with something. Less likely.

It should be noted that the present invention is not limited to only the above embodiment. For example, as shown in FIG. 10, both ends of the second member 7 in the longitudinal direction of the second member 7 have the same shape as the conventional example, without providing the second member 7 with the convex portion 72 and the concave portion 72A as in the first and second embodiments. 71 (including both wall portions 75, 75), substantially parallel lines Z with respect to a line along the center of gravity G in the longitudinal center _{O 2} of the second member 7, planar by cutting along the Z Any surface may be used. Also, as shown in FIGS. 11 and 12, grooves 76, 76 are formed at two inner corners of the second member 7 of the first and second embodiments, which are boundaries between the top plate portion 74 and the two wall portions 75, 75. It may be provided. These grooves 76, 76 are provided with protrusions at corners corresponding to two inner corners of the second member 7 in a receiving mold (not shown) used when bending the second member 7 from one metal plate. The inner corner is depressed by the ridges at the corners of the receiving mold. The grooves 76 serve to alleviate the concentration of stress on the inner edges at the time of bending the second member 7, and can prevent cracks from being generated at the inner edges. Lubricating oil is also accumulated, so that the lubrication of the sliding contact portion with the valve stem V is improved. Further, the present invention can be applied to a case in which the pivot engagement portion 63 of the first member 6 is formed in a hemispherical shape or a screw hole.

FIG. 2 is a longitudinal sectional side view of a first embodiment of the rocker arm of the present invention. FIG. 3 is an exploded perspective view of the rocker arm according to the first embodiment. FIG. 3 is a top view of the rocker arm according to the first embodiment. FIG. 3 is a perspective view of a second member alone according to the first embodiment. FIG. 4 is a longitudinal side view for explaining a mounting state of a second member of the first embodiment. The manufacturing process figure of the 2nd member of a 1st example. FIG. 6 is an exploded perspective view of a rocker arm according to a second embodiment of the present invention. FIG. 11 is a top view of the rocker arm according to the second embodiment. The perspective view of the 2nd member single body of a 2nd example. The manufacturing process figure of the 2nd member of a 3rd example. FIG. 13 is a perspective view of a second member alone according to a fourth embodiment. The perspective view of the 2nd member single body of a 5th example. FIG. 6 is a longitudinal sectional side view of a rocker arm of a conventional example. The perspective view of the rocker arm of the conventional example. The top view of the rocker arm of the conventional example. The manufacturing process figure of the 2nd member of a prior art example.

Explanation of reference numerals

REFERENCE SIGNS LIST 1 rocker arm 2 frame 3 roller 6 first member of frame 61 first member wall 62 connecting portion of first member 63 pivot engaging portion of connecting portion 7 second member of frame 71 end portion of second member in longitudinal direction 72 Convex part of second member 73 End face of convex part

Claims (3)

A rocker arm that opens and closes a valve provided on a cylinder head with rotation of a cam,
A roller with which the cam is in contact, and a press-made frame that rotatably supports the roller,
The frame is substantially parallel and opposed to each other, and a pair of wall portions to which the roller is rotatably mounted in the middle in the longitudinal direction, and a pivot engagement provided so as to connect one longitudinal end of the pair of wall portions in a cross-linked manner. And a valve engaging portion provided so as to connect the other end in the longitudinal direction of the pair of wall portions in a cross-linked manner,
The rocker arm, wherein the valve engagement portion is curved along a longitudinal direction of the wall portion and is also curved along a width direction of the wall portion. A rocker arm that opens and closes a valve provided on a cylinder head with rotation of a cam,
A roller with which the cam is in contact, and a press-made frame that rotatably supports the roller,
The frame has a two-piece structure composed of two members, a first member of the two members, a pair of wall portions disposed substantially parallel and opposed to each other so as to rotatably support the roller in the middle in the longitudinal direction, And a connecting portion provided at one end in the longitudinal direction of the pair of wall portions in a cross-linking manner therebetween and provided with a pivot engaging portion, wherein a second member of the two members is the second member. A valve engaging portion is formed by being joined and fixed in a bridging manner between the pair of wall portions of the one member at the other longitudinal ends thereof,
The rocker arm, wherein the second member is curved along a longitudinal direction of the wall and is also curved along a width of the wall. The second member is formed to have a substantially inverted U-shaped cross section, and a pair of opposed wall portions of the second member is joined to the pair of wall portions, thereby forming a top of the second member. The rocker arm according to claim 2, wherein a plate portion is disposed halfway in the height direction of the pair of wall portions.

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