JP2003138914A - Rocker arm and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a rocker arm, in which a shaft hole is formed in a state of properly keeping relationships of a first connecting part and a second connecting part to the shaft hole, without lowering strength of a position for forming the shaft hole. SOLUTION: The rocker arm has a pair of side wall parts 13 formed to be opposite to each other and a first connecting part 11 and a second connecting part 12 connecting the pair of the side wall parts 13, respectively. The first connecting part 11 and the pair of side wall parts 13 form an approximately U-shaped section. Each of side wall parts 13 has a projecting part 131 projecting toward a bottom part side 101 of an approximately U-shaped section and a shaft hole 15. The whole board thickness (t) of the projecting portions 131 is approximately uniform and the projecting amount H is 80% or more of a value calculated by subtracting the board thickness (t) of the projecting parts 131 from spacing W between inner faces 136.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a rocker arm for transmitting a driving force for opening and closing a valve in an engine and a method for manufacturing the rocker arm.

[0002]

2. Description of the Related Art As shown in FIGS. 33 to 35, a conventional rocker arm 9 includes a pair of side wall portions 93 formed to face each other, a first connecting portion 91 and a second side wall portion 93 connecting the pair of side wall portions 93. And a connecting portion 92. The first connecting portion 91 and the second connecting portion 92 each have a substantially U-shaped cross section together with the pair of side wall portions 93.
Further, the first connecting portion 91 forms a support portion 911 that supports the valve stem portion 31 of the valve 3 of the engine 7. Further, the cam 2 is provided on the pair of side wall portions 93.
2 forms a shaft hole 95 for mounting the main shaft 211 of the roller 21 which is driven to rotate.

In the rocker arm 9, the roller 21 is assembled in the shaft hole 95, the valve stem portion 31 of the valve 3 is supported in the support portion 911, and the second connecting portion 92 is rotated by the rocker arm 9. It is used by engaging with the pivot 4, which is the center of movement.

As shown in FIG. 35, the rocker arm 9 is
Is formed by forming protrusions 931 on both sides of the hollow portion 94 of the metal plate 90 and bending the protrusions 931 in the direction of the bottom 901 side (arrow A direction) of the above-mentioned substantially U-shaped cross section.
(See FIG. 34). That is, in the rocker arm 9, the projecting portion 931 is projected in the direction opposite to the direction in which the side wall portion 93 is extended from the first connecting portion 91 and the second connecting portion 92. A shaft hole 95 is provided at a position surrounded by the protruding portion 931 so that the roller 2
1, and a rocker arm 9 is formed.

[0005]

By the way, in the rocker arm 9, it is structurally stable that the roller 21 has a wider space between the line connecting the first connecting portion 91 and the second connecting portion 92. To do. However, in the above-mentioned conventional rocker arm 9, if an attempt is made to increase the distance,
The formation position of the shaft hole 95 is such that the protruding tip surface 932 of the protruding portion 931 is formed.
It will be located in the vicinity of. Therefore, in this case, the strength of the formation position of the shaft hole 95 decreases.

Therefore, the distance between the shaft hole 95 and the line connecting the first connecting portion 91 and the second connecting portion 92 cannot be made too wide. As described above, in the conventional rocker arm 9, the protrusion amount of the protrusion 131 is not sufficient. Therefore, the shaft hole 95 is inserted into the first connecting portion 91 and the second connecting portion 92 while maintaining the strength around the shaft hole 95.
It is difficult to form them while maintaining a proper positional relationship with.

The present invention has been made in view of the above conventional problems, and maintains the positional relationship between the first connecting portion and the second connecting portion appropriately without lowering the strength of the position where the shaft hole is formed. An object of the present invention is to provide a rocker arm capable of forming a shaft hole in a closed state and a manufacturing method thereof.

[0008]

According to a first aspect of the present invention, a pair of side wall portions formed so as to face each other, a first connecting portion and a second connecting portion connecting the pair of side wall portions, the first connecting portion, and A hollow portion formed between the first connecting portion and the second connecting portion, the first connecting portion forms a substantially U-shaped cross section together with the pair of side wall portions, and the valve stem portion is formed inside the U-shaped portion. The pair of side wall portions has a pair of projecting portions projecting toward the bottom side of the substantially U-shaped cross section and are arranged on the projecting portions. The projecting portion has a substantially uniform plate thickness t, and the projecting amount from the bearing surface of the first connecting portion to the tip of the projecting portion is H, Where W is the distance between the inner surfaces of the protrusions, the relationship of H ≧ 0.8 (W−t) is satisfied. In the rocker arm, characterized in that (claim 1).

In the rocker arm of the present invention, the pair of side wall portions are provided with a direction toward the bottom side having the substantially U-shaped cross section, that is, a direction in which the side wall portions are extended from the first connecting portion and the second connecting portion. And a protrusion that protrudes in a direction opposite to the direction. And the total plate thickness t of this protrusion
Is substantially uniform, and the protrusion amount H of the protrusion is 80% or more of the value obtained by subtracting the plate thickness t of the protrusion from the distance W between the inner side surfaces.

That is, first, the protrusion amount H of the protrusion is much larger than that in the conventional case. Therefore, by positioning the shaft hole so as to be surrounded by the protrusion, the positional relationship between the shaft hole and the first connecting portion and the second connecting portion can be made more appropriate than before. That is, when the rocker arm is installed in the engine, the gap between the cam and the first connecting portion and the second connecting portion can be set wide. Further, as described above, the plate thickness of the entire projecting portion is substantially uniform, and the plate thickness hardly changes even in the vicinity of the outer peripheral edge thereof. Therefore, the shaft hole can be formed in a state where the positional relationship between the first connecting portion and the second connecting portion is appropriately maintained without lowering the strength of the portion around the shaft hole.

According to a second aspect of the present invention, a metal plate is punched to form a hollow portion and a pair of projecting portions that face each other with the hollow portion sandwiched between them. A bending step of forming a first connecting portion and a second connecting portion that connect the pair of side wall portions to each other while facing the pair of side wall portions having the protruding portion, and at least an outer surface and an inner side surface of the pair of protruding portions. A step of deforming and moving the protrusion so as to further protrude in the protruding direction in a state that the protrusion is restrained, and a pressure deforming step of increasing the protrusion amount of the protrusion is included. (Claim 3).

In the rocker arm manufacturing method of the present invention, the hollow portion is formed by punching the metal plate in the punching step. The shape of the hollow portion is such that a pair of projecting portions facing each other with the hollow portion sandwiched therebetween is formed.

Also, in the bending step, the metal plate having the hollow portion is bent. As a result, the pair of side wall portions having the above-mentioned protrusions are formed to face each other, and the first connecting portion and the second connecting portion that connect them are formed. Then, a substantially U-shaped cross section is formed by the first connecting portion and the pair of side wall portions, and a substantially U-shaped cross section is formed by the second connecting portion and the pair of side wall portions. Further, due to the bending, the protruding portion is on the side opposite to the direction of the U-shaped bottom portion side in the substantially U-shaped cross section, that is, the direction in which the side wall portion is extended from the first connecting portion and the second connecting portion. Stand so that it projects in the direction of.

Then, in the pressurizing and deforming step, the protruding portion is deformed and moved in the protruding direction to increase the protruding amount of the protruding portion. At this time, an important point is that the deformation movement is performed while at least the outer side surface and the inner side surface of the pair of protrusions are constrained. As a result, it is possible to prevent the protruding portion from being deformed in the plate thickness direction, and it is possible to increase the protruding amount without substantially changing the plate thickness of the protruding portion. Therefore, by manufacturing the rocker arm by performing the above steps,
As shown in the first aspect of the invention, it is possible to manufacture a rocker arm that exhibits excellent effects.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The preferred embodiments of the present invention described above will be described. In the above first invention,
The fact that the protrusions satisfy the relationship of H ≧ 0.8 (W−t) and the overall plate thickness t of the protrusions is substantially uniform means the following. That is, when forming the rocker arm using a metal plate, the hole shape of the hollow portion is devised to previously form a pair of protrusions that protrude inward from each other.

Then, the rocker arm is formed by applying a protruding portion raising method in which these protruding portions are bent and raised along two substantially parallel bending lines passing near the respective base end portions. In this case, the space between the bending lines is the space between the inner side surfaces after the protruding portions are erected. In addition, as a practical problem, there is an influence of the minimum punching width when punching the hollow portion, an influence of the plate thickness of the metal plate when bending, and the like. Therefore, it is extremely difficult to set the protrusion amount H of the protruding portion to 80% or more of the value obtained by subtracting the plate thickness t of the protruding portion from the distance W between the inner side surfaces.

As described above, according to the first aspect of the present invention, while the plate thickness of the entire protruding portion is kept substantially uniform, the protruding portion is positively protruded to a range almost impossible by the protruding portion raising method. The amount H is increased. The amount of protrusion H is calculated from the distance W between the inner side surfaces to the thickness t of the protrusion.
If less than 80% of the value after subtracting
The effect of improving the positional relationship between the connecting portion and the second connecting portion and the shaft hole is reduced.

An example for explaining the effect of improving the protrusion amount of the protrusion is as follows. That is, for example, W = 1
Considering the case of 1.5 mm and t = 3.2 mm, W-t
= 8.3 mm, this half is 4.15 mm. That is, in this case, it means that H cannot be made larger than 4.15 mm simply by performing the above-mentioned bending.

On the other hand, in the relationship of H ≧ 0.8 (Wt), 0.8 (11.5-3.2) = 6.6.
This means that H of 4 mm or more can be secured. H ≧
As an example when the relationship of 0.8 (W−t) is satisfied,
When W = 11.5 mm and t = 3.2 mm, H is set to 8.
It may be 3 mm. In this case, 8.3 ≧ 6.64
As a result, it is possible to provide a rocker arm satisfying the relationship of H ≧ 0.8 (W−t). (In this case, the relationship of H ≧ (W−t) is also satisfied.)

Further, in the first aspect of the present invention, the projecting portion restrains at least the outer side surface and the inner side surface of the pair of projecting portions, and the pair of side wall portions, the first connecting portion, and the second side portion. It is preferable that the connecting portion and the connecting portion are formed by pressing in opposite directions. In this case, H ≧ 0.8
It is possible to easily form a protrusion having a large protrusion amount H that satisfies the relationship of (W−t).

In the first aspect of the invention, it is preferable that the plate thickness t of the protruding portion is 2 mm or more (claim 2). In this case, when the shaft hole is formed at the position where the protrusion is formed, the strength of the position where the shaft hole is formed can be sufficiently maintained.

In the manufacturing method of the second aspect of the invention, it is preferable that the pair of side wall portions face each other substantially in parallel after the bending step is performed. In this case, when the pressurizing and deforming step is performed, the device used for the pressurizing and deforming step is simplified, and the deformable movement of the protruding portion can be easily performed. In addition, after performing the bending step, the pair of side wall portions may be inclined to face each other. In this case, as will be described later, after performing the pressure deformation step, the pair of inclined side wall portions can be formed so as to face each other in parallel.

Further, in the pressurizing and deforming step, the protrusion has a protrusion amount H from the bearing surface of the first connecting portion to the tip of the protrusion, and a distance between inner side surfaces of the pair of protrusions. W, H ≧, where t is the plate thickness of the protrusion
It can be projected until the relationship of 0.8 (W-t) is satisfied (claim 4). In this case, it is possible to manufacture the rocker arm in which the positional relationship between the first connecting portion and the second connecting portion and the shaft hole is improved, as in the above-described first invention, by making the protruding portion largely protrude. it can.

The plate thickness t of the protrusion is preferably 2 mm or more (claim 5). In this case, when the shaft hole is formed at the position where the protrusion is formed, the strength of the position where the shaft hole is formed can be sufficiently maintained. Further, according to the method of manufacturing the rocker arm, the rocker arm in which the positional relationship between the first connecting portion and the second connecting portion and the shaft hole is improved in a state where the plate thickness t of the protruding portion is maintained at 2 mm or more. Can be manufactured.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) As shown in FIG. 1, a rocker arm 1 of this embodiment
Is a pair of side wall portions 13 formed to face each other.
And a first connecting portion 11 and a second connecting portion 12 that connect the pair of side wall portions 13, respectively. The pair of side wall portions 13 are formed to face each other by bending using the metal plate 10 having the hollow portion 14 in the vicinity of both lateral end portions 141 of the hollow portion 14 (see FIG. 7). In addition, the first connecting portion 11 and the second connecting portion 12 connect the pair of side wall portions 13 at the front and rear of the hollow portion 14 in the vertical direction, respectively.

In this example, the lateral direction means the direction in which the pair of protrusions 131 are located when the hollow portion 14 and the protrusion 131 are formed by punching described later,
The vertical direction means a direction orthogonal to the horizontal direction.

The first connecting portion 11 and the pair of side wall portions 13 form a substantially U-shaped cross section. Also, the first
The connecting portion 11 constitutes a bearing surface 111 that supports a valve stem portion 31 of the valve 3 described later in a U-shaped interior 103 having a substantially U-shaped cross section. In addition, the second connecting portion 12
Similarly, together with the pair of side wall portions 13, a substantially U-shaped cross section is formed.

Further, as shown in FIGS. 2 to 4, the pair of side wall portions 13 has a pair of projecting portions 131 projecting in the direction of the bottom portion 101 (direction of arrow A) having a substantially U-shaped cross section. ing. In addition, a pair of shaft holes 15 for mounting a main shaft 211 of the roller 21, which will be described later, are provided at the positions where the protrusions 131 are formed on the pair of side wall parts 13. In this example, the protrusion 131 has a substantially uniform plate thickness t. In addition, the protrusion 131 is formed from the bearing surface 111 of the first connecting portion 11 to the protrusion 131.
Where H is the amount of protrusion up to the protruding tip surface 132, which is the tip of the pair, and W is the distance between the inner side surfaces 136 of the pair of protruding portions 131, the relationship of H ≧ 0.8 (W−t) is satisfied. .

In the present embodiment, the state where the plate thickness t of the entire protrusion 131 is substantially uniform means that the hollow portion 14 and the protrusion 131 are formed by punching the metal plate 10 in the punching process described later. When the sheet thickness t is formed,
Change beyond the range in which the sag formed near the outer periphery of the protrusion 131 (a portion whose shape has collapsed due to chamfering due to sagging of the periphery of the protrusion 131) is allowed. It refers to the state of not doing.

This will be described in detail below. As shown in FIGS. 1 to 4, the bearing surface 111 of the first connecting portion 11 is shown.
Is the vertical direction of the hollow portion 14, that is, the rocker arm 1
Is formed in an arc shape in the longitudinal direction. In addition, the pair of side wall portions 1 located on both sides of the first connecting portion 11
The portion 3 forms a stem guide portion 133 that guides the valve stem portion 31. The distance W1 between the inner side surfaces 136 of the stem guide portion 133 is smaller than the distance W between the inner side surfaces 136 of the protrusion 131.

In this example, the protrusion amount H is
The bearing surface 111 of the first connecting portion 11 and the second connecting portion 12
When the line connecting the opening side surface 138, which is a surface located on the opening side 102 having a substantially U-shaped cross section, is defined as a reference line L1, the protruding tip surface 1 of the protruding portion 131 is defined from the reference line L1.
The distance is up to 32 (see FIG. 4). Further, in this example, the overall plate thickness t of the protruding portion 131 is 2 mm or more, which is substantially the same as the overall plate thickness of the side wall portion 13. That is, in the rocker arm 1 of this example, no deformation force is applied to the pair of side wall portions 13 in the plate thickness direction, and the plate thickness of the pair of side wall portions 13 is hardly changed.

Further, as shown in FIG. 5, the second connecting portion 12 forms a mounting portion 12 which is mounted on the pivot 4 which is the rotation center of the rocker arm 1. In addition, in the present example, the pair of shaft holes 15 are formed so that the center of the hole is located in each of the protrusions 131. Also,
The pair of side wall portions 13 do not protrude much to the opening side 102 opposite to the bottom side 101 having the substantially U-shaped cross section. As a result, when the rocker arm 1 is used to construct the engine 7, it is possible to easily avoid interference between the rocker arm 1 and the components such as the valve 3 located around the rocker arm 1.

Next, the valve 3 by the rocker arm 1
The opening / closing operation of will be described. As shown in FIG. 5, the valve 3 that performs at least one of intake and exhaust of mixed gas or the like in the engine 7 is opened and closed by transmitting the driving force by the rotation of the cam 22 by the rocker arm 1.

When the cam 22 rotates, the roller 21 attached to the rocker arm 1 is driven to rotate, and at the same time, the cam 22 pushes down the rocker arm 1. At this time, the rocker arm 1 rotates about the rotation center portion 41 of the pivot 4. Here, the rocker arm 1 has a bearing surface 111.
Is the tip portion 3 of the valve stem portion 31 of the valve 3
It is in contact with 11. Therefore, the valve 3 is pushed down and opened by the rotation of the rocker arm 1. When the cam 22 further rotates, the valve 3 is closed by the retainer 33 fixed to the valve 3 being pushed up by the pushing force of the spring 32. Thus, valve 3
The opening / closing operation of is performed.

Next, a method of manufacturing the rocker arm 1 will be described. The rocker arm 1 in this example is formed by press working. First, as shown in FIG. 6, as a punching step, the metal plate 10 is punched by a punching die (not shown),
The outer shape 100 of the rocker arm 1 is formed. At this time, in the lateral direction of the outer shape 100, the convex portion 139 is deformed and moved in order to increase the protrusion amount of the protrusion 131.
Is formed.

Further, as shown in FIG. 7, the metal plate 10 is punched by another punching die (not shown) to form a hollow portion 14 and a pair of protruding portions 131 facing each other in the lateral direction of the hollow portion 14. . At this time, the protrusion 131 is formed so as to protrude toward the inside of the hollow portion 14 such that the hole shape of the hollow portion 14 is narrowed in the lateral direction. In addition, the protrusion 131 is formed to have a convex curve. In addition, as shown in FIG.
An engaging portion 121 that engages with the pivot 4 is formed at a position where the connecting portion 12 is formed.

Next, as a bending step, the hollow portion 1 is
The metal plate 10 on which the 4 is formed is bent at the bending line L2 shown in FIG.
Bend with starting point of bending. As shown in FIGS. 9 to 12, in the bending step, the inner punch 51 positioned on the opening side 102 in the substantially U-shaped cross section of the rocker arm 1 to be formed and the bottom side 101 in the substantially U-shaped cross section of the rocker arm 1 are formed. A forming die 5 is used which is composed of the outer punch 52 positioned and the die 53 positioned on the outer circumference of the inner punch 51 and the outer punch 52 so as to surround them.

The inner punch 51 is provided with a convex portion 511 to be inserted into the hollow portion 14 of the metal plate 10, and the outer punch 52 is provided with a concave portion 521 in which the convex portion 511 can be arranged. There is. Then, first, as shown in FIG. 9, the metal plate 10 is arranged between the inner punch 51 and the outer punch 52 and sandwiched between them.

Next, as shown in FIGS. 10 to 12, the inner punch 51 and the outer punch 52 with the metal plate 10 held therebetween and the die 53 are relatively moved to bend the metal plate 10 into the bent state. The line L2 (see FIG. 8) is used as the starting point of bending and is bent.

At this time, as shown in FIGS. 13 and 14,
The projecting portion 131 stands up on the bottom side 101 in the substantially U-shaped cross section, and the side wall portion 13 excluding the projecting section 131 stands up on the opening side 102 opposite to the bottom side 101. At this time, the convex portion 139 is located on the opening side 102 of the pair of side wall portions 13.

The projecting portion 131 projects toward the bottom side 101 having a substantially U-shaped cross section. In addition, at the time of bending, before and after the hollow portion 14 in the vertical direction, the first connecting portion 11 and the pair of side wall portions 13 have a substantially U-shaped cross section, and the second connecting portion 12 and the pair of side wall portions 13 are formed. To form a substantially U-shaped cross section. Thus,
An intermediate body 105 having a substantially U-shaped cross section is formed from the metal plate 100.

Then, as a pressure deformation step, the protruding portion 131 is deformed and moved in the protruding direction, that is, in the direction of the bottom side 101 in the substantially U-shaped cross section to increase the protruding amount H of the protruding portion 131. Let At this time, the deformation movement is performed in a state where at least the outer side surface 135 and the inner side surface 136 of the pair of protrusions 131 are constrained (see FIG. 22).

As shown in FIGS. 15 to 17, in the pressurizing and deforming step, a section U of the rocker arm 1 to be molded is formed.
An inner punch 61 located on the opening side 102 in the shape of a letter,
Bottom side 101 of rocker arm 1 having a substantially U-shaped cross section
The forming die 6 is composed of the outer punch 62 located at the above position and the die 63 located at the outer circumference of the inner punch 61 and the outer punch 62 so as to surround them.

The inner punch 61 is located in the U-shaped interior 103 (see FIGS. 1 and 2) of the rocker arm 1 to be molded having a substantially U-shaped cross section, and the intermediate body 105 (see FIG. 13).
It has an inner shape portion 611 that is inserted into the hollow portion 14. Further, the outer punch 62 is an outer shape portion 621 located on the bottom side 101 of the rocker arm 1 having a substantially U-shaped cross section.
have. Further, the die 63 has an inner peripheral shape portion 631 into which the inner punch 61 and the outer punch 62 can be inserted.

Then, as shown in FIGS. 17 and 18, in the pressure deformation step, first, the intermediate body 105 is
Are placed on the outer punch 62 placed inside the die 63. Then, as shown in FIG. 19, the outer punch 6 is
2 and the die 63 and the inner punch 61 are relatively moved so as to approach each other. Then, the tip forming surface 613 of the inner punch 61 presses the convex portions 139 of the pair of side wall portions 13 to the bottom side 101 having a substantially U-shaped cross section, and the outer shape portion 621 of the outer punch 62 makes the first connection. Part 1
The first and second connecting portions 12 are provided with an opening side 102 having a substantially U-shaped cross section.
Pressurize. Thus, the pair of side wall portions 13 and the first connecting portion 11 and the second connecting portion 12 are pressed in opposite directions.

At this time, the convex portion 139 and the projecting portion 131 of the pair of side wall portions 13 are deformed and moved by the pressurizing in the projecting direction thereof, that is, in the direction of the bottom portion side 101. Thus, as shown in FIGS.
The protrusion 131 is protruded until the protrusion amount H becomes 80% or more of the value obtained by subtracting the plate thickness t of the protrusion from the distance W between the inner side surfaces.

Further, as shown in FIGS. 22 and 23, when the deformation movement is performed, the inner side surface 136 of the entire side wall portion 13 including the protrusion 131 is formed by the inner shape portion 611 of the inner punch 61. The inner peripheral shape portion 631 of the die 63 restrains the outer side surface 135 of the entire side wall portion 13 including the protruding portion 131. Therefore, the pair of side wall portions 13 each having the protrusion 131 cannot be deformed in the plate thickness direction. Therefore, the protrusion 131 can be prevented from being deformed in the plate thickness direction, and the protrusion 13 can be prevented.
No change in the plate thickness of 1
It is possible to increase the protrusion amount H of the.

As described above, as shown in FIGS. 24 and 25, the plate thickness t of the entire protrusion 131 is substantially uniform, and the relationship of H ≧ 0.8 (W−t) is satisfied. The rocker arm 1 can be molded. Further, as shown in FIGS. 1 and 4, after the rocker arm 1 is formed, as a shaft hole forming step, at the formation position of the protrusion 131 in the pair of side wall portions 13, that is, the hole center is the protrusion 13
The shaft hole 15 is bored at the position 1.

As shown in FIG. 5, when the engine 7 is constructed by using the rocker arm 1 formed by the method for manufacturing the rocker arm 1, the rocker arm 1 has the bottom side 101 in the substantially U-shaped cross section and the cam 22 side. Place it toward. Therefore, the supporting surface 111 for supporting the valve stem portion 31 of the valve 3 and the stem guide portion 133 for guiding the valve stem portion 31 can be easily utilized by utilizing the substantially U-shaped cross section after the bending. Can be formed.

Further, as described above, in this example, the protrusion amount H of the protrusion 131 is much larger than that in the conventional case. Therefore, by positioning the shaft hole 15 so as to be surrounded by the protrusion 131, the first connecting portion 11
Also, the positional relationship between the second connecting portion 12 and the shaft hole 15 can be made more appropriate than before. That is, the shaft hole 1
5 can be formed at a position largely separated from the first connecting portion 11 and the second connecting portion 12. Therefore, when the rocker arm 1 is assembled into the engine 7, the first
The interval between the connecting portion 11 and the second connecting portion 12 and the cam 22 can be set wide. In addition, this makes it possible to set a wide gap between the cam 22 and the valve stem portion 31 of the valve 3 and the pivot center portion 41 of the pivot.

Further, as described above, the protrusion 1
The plate thickness t of 31 is substantially uniform, and the plate thickness of the protruding tip surface 132, which is the outer peripheral end surface, hardly changes. Therefore, in the rocker arm 1 of this example, the strength of the position where the shaft hole 15 is formed is not lowered, and the positional relationship between the first connecting portion 11 and the second connecting portion 12 is appropriately maintained. The shaft hole 15 can be formed.

(Embodiment 2) In this embodiment, in the bending step, the pair of side wall portions 13 are not formed to face each other in parallel, but the pair of side wall portions 13 have an inclination angle. It is an example in which they are formed so as to face each other. FIG. 26,
As shown in FIG. 27, in the bending step of this example, when the metal plate 10 is bent at the bending line L2 as a starting point of bending, the cross section is formed by the first connecting portion 11 and the pair of side wall portions 13. The substantially U-shaped opening side 102 forms a substantially U-shaped cross section in a state in which the opening side 102 is open outward. At this time,
The pair of side wall portions 13 face each other with an inclination angle.

Then, as shown in FIGS. 28 and 29, in the pressurizing and deforming step of this embodiment, the first connecting portion 11 and the second connecting portion 12 and the pair of side wall portions 13 are moved in opposite directions. The pressure is applied to further deform and move the protrusion 131 in the protrusion direction of the protrusion 131 along the inclined side wall 13. Further, after performing the pressurizing and deforming step, the bending is performed again with the bending line L2 as a bending starting point so that the pair of side wall portions 13 face each other in parallel. Others are the same as those in the first embodiment.

Also in this example, as in the first embodiment,
It is possible to mold the rocker arm 1 in which the plate thickness t of the entire projection 131 is substantially uniform and the relationship of H ≧ 0.8 (W−t) is satisfied. Other than the above, Example 1
It is possible to obtain the same operational effect as.

(Embodiment 3) In this embodiment, as shown in FIGS. 30 and 31, before the punching step, the metal plate 10 is removed.
2 is an example in which the drawing step is performed to form the drawn portion 19 by performing drawing processing at the position where the hollow portion 14 is formed.
Then, as shown in FIG. 32, in the punching step, the hollow portion 14 is formed at the position where the narrowed portion 19 is formed, and the protruding portion 131 deformed in the plate thickness direction is formed.

Then, in the bending step, the metal plate 10 is bent by using the forming die 5, and the protrusion 131 is formed on the bottom side 10 in the substantially U-shaped cross section.
1, and the side wall portion 13 excluding the protrusion 131 is raised on the opening side 102. Others are the same as those in the first embodiment.

In this example, when the metal plate 10 is bent in the bending step, the protrusion of the narrowed portion 19 is utilized to cause the protrusion 131 to move toward the bottom surface 101 in a substantially U-shaped cross section. It can be made to project greatly toward. Therefore, it is possible to reduce the amount of deformation movement of the protrusion 131 in the pressure deformation step. In addition, it is possible to obtain the same effect as that of the first embodiment.

[Brief description of drawings]

FIG. 1 is a perspective view showing a rocker arm according to a first embodiment.

FIG. 2 is a side view showing the rocker arm according to the first embodiment.

FIG. 3 is a plan view showing a rocker arm according to the first embodiment.

FIG. 4 is a diagram showing a rocker arm according to the first embodiment,
Sectional drawing in the AA arrow in FIG.

FIG. 5 is an explanatory diagram showing a rocker arm mounting structure according to the first embodiment.

FIG. 6 is a plan view showing a metal plate that has been subjected to a punching process in Example 1.

FIG. 7 is a plan view showing a metal plate in which a hollow portion and a protruding portion are formed by performing a punching process in the first embodiment.

FIG. 8 is an explanatory view showing the metal plate in the first embodiment, in which the engaging portion that engages with the pivot is formed at the position where the second connecting portion is formed.

FIG. 9 is a view showing a bending step in Example 1, and a cross-sectional view showing the forming die before being bent.

FIG. 10 is a diagram showing a bending step in Example 1,
Sectional drawing of the longitudinal direction which shows the shaping | molding die in the state after bending.

11 is a view showing the forming die in a state after being bent in a bending step in Example 1, and is a cross-sectional view taken along the line AA of FIG.

FIG. 12 is a view showing the forming die in a state after bending in the bending step in Example 1, and is a cross-sectional view taken along the line BB of FIG.

FIG. 13 is a perspective view of an intermediate body formed in a bending process in Example 1.

14 is a view showing an intermediate body formed in a bending step in Example 1, and is a cross-sectional view taken along the line AA in FIG.

FIG. 15 is a plan view showing the outer punch and the die in the pressure deformation step in the first embodiment.

FIG. 16 is a plan view showing the inner punch in the pressure deformation step in the first embodiment.

FIG. 17 is a view showing the forming die before a deformation movement in the pressure deformation step in the embodiment 1, and is a cross-sectional view at the position of the side wall portion.

FIG. 18 is a view showing the forming die before being deformed and moved in the pressurizing and deforming step in Embodiment 1, and is a cross-sectional view at the positions of the first connecting portion and the second connecting portion.

FIG. 19 is an explanatory cross-sectional view showing the molding die in a state of deformation movement in the pressure deformation step in the first embodiment.

FIG. 20 is a view showing the forming die after the deformation movement in the pressure deformation step in the embodiment 1, and is a cross-sectional view at the position of the side wall portion.

FIG. 21 is a view showing the forming die in a state after deformation and movement in the pressure deformation step in Embodiment 1, and is a cross-sectional view at the positions of the first connecting portion and the second connecting portion.

22 is a view showing the molding die in a state after deformation and movement in the pressure deformation step in Embodiment 1, which is indicated by A in FIG.
-A arrow sectional view.

FIG. 23 is a view showing the molding die in a state after deformation and movement in the pressure deformation step in Embodiment 1, which is indicated by B in FIG.
-B arrow sectional drawing.

FIG. 24 is a perspective view showing the rocker arm formed in the pressure deformation step in the first embodiment.

FIG. 25 is a diagram showing the rocker arm formed in the pressure deformation step in the first embodiment, which is taken along the line AA in FIG.
FIG.

FIG. 26 is a plan view showing an intermediate body formed in a bending process in Example 2.

FIG. 27 is a side view showing an intermediate body formed in a bending step in Example 2.

FIG. 28 is a plan view showing the rocker arm formed in the pressure deformation step in the second embodiment.

FIG. 29 is a side view showing the rocker arm formed in the pressure deformation step in the second embodiment.

FIG. 30 is a plan view showing a state in which a narrowed portion is formed in a narrowing step in the third embodiment.

FIG. 31 is a view showing a state in which a narrowed portion is formed in the narrowing step in the third embodiment, and is a cross-sectional view taken along the line AA in FIG. 30.

32 is a view showing a state in which a hollow portion and a protruding portion are formed in the punching process in Example 3, and is a cross-sectional view corresponding to the arrow AA in FIG. 30. FIG.

FIG. 33 is an explanatory view showing a rocker arm mounting structure in a conventional example.

FIG. 34 is a perspective view showing a rocker arm in a conventional example.

FIG. 35 is a plan view showing a metal plate in a conventional example.

[Explanation of symbols]

1. ． ． Rocker arm, 10. ． ． Metal plate, 101. ． ． Bottom side, 102. ． ． Opening side, 11. ． ． The first connecting part, 111. ． ． Bearing surface, 12. ． ． The second connecting part, 13. ． ． Side wall, 131. ． ． Protrusion, 135. ． ． Outer surface, 136. ． ． Inside surface, 14. ． ． Hollow part, 15. ． ． Shaft hole,

Continued front page    F term (reference) 3G016 AA06 BB09 BB22 CA04 CA22                       CA45 EA24 FA06 FA07 GA01                       GA05

Claims (5)

[Claims] 1. A pair of side wall portions formed so as to face each other, and a first connecting portion and a second connecting portion for connecting the pair of side wall portions.
A connecting part and a hollow part formed between the first connecting part and the second connecting part, and the first connecting part forms a substantially U-shaped cross section with the pair of side wall parts. , A bearing surface for supporting the valve stem portion is formed inside the U-shape, and the pair of side wall portions has a pair of projecting portions projecting toward the bottom side of the substantially U-shaped cross section. In addition, the projection has a shaft hole arranged therein, the projection has a substantially uniform plate thickness t, and the projection of the projection from the bearing surface of the first connecting portion. A rocker arm satisfying a relationship of H ≧ 0.8 (W−t), where H is a protrusion amount up to the tip and W is a distance between inner side surfaces of the pair of protrusions. 2. The plate thickness t of the protrusion according to claim 1.
Is a rocker arm that is 2 mm or more. 3. A punching step of punching a metal plate to form a hollow portion and a pair of projecting portions that face each other with the hollow portion sandwiched therebetween; and a step of bending the metal plate to have the pair of projecting portions. Bending step of facing the pair of side wall portions and forming a first connecting portion and a second connecting portion that connect the pair of side wall portions, and a state in which at least the outer side surface and the inner side surface of the pair of projecting portions are constrained The method of manufacturing a rocker arm according to claim 1, further comprising the step of deforming and moving the protruding portion so as to further protrude in the protruding direction to increase the protruding amount of the protruding portion. 4. The pressure deformation step according to claim 3, wherein the projection has a substantially uniform plate thickness t, and a tip of the projection from the bearing surface of the first connecting portion. Up to H and the distance between the inner surfaces of the pair of protrusions is W, the protrusion is performed until the relationship of H ≧ 0.8 (W−t) is satisfied. . 5. The rocker arm manufacturing method according to claim 3, wherein the plate thickness t of the protrusion is 2 mm or more.