JP4368518B2 - Rocker arm manufacturing method - Google Patents

Description

[0001]
【Technical field】
The present invention relates to a method for manufacturing a rocker arm that transmits a driving force for opening and closing a valve in an engine.
[0002]
[Prior art]
Conventionally, a rocker arm has been used as a component that transmits a driving force for opening and closing a valve in an engine.
As shown in FIG. 10 (a), the rocker arm 9 includes a bearing portion 92 provided with a pair of shaft holes 921 for attaching the main shaft of the roller at the center portion, and a support portion 91 for supporting the valve stem portion of the valve at one end. The other end has an attachment portion 93 attached to a pivot serving as a rotation center.
Further, the rocker arm 9 has a U-shaped cross section, and the bearing portion 92 is placed on a pair of side walls 94 having a U-shaped cross section, and the base side on the side opposite to the opening tip side 95 having the U-shaped cross section. 96 includes the support portion 91 and the attachment portion 93.
[0003]
As shown in FIG. 10 (c), when the rocker arm 9 is formed by press working, first, a plate-shaped material piece 90 is punched, and the material piece 90 is formed with a punching hole 97 in the central portion. The rocker arm 9 having the developed shape 901 is formed.
Next, the material piece 90 having the developed shape 901 is subjected to bending processing using the both side portions 971 of the punched hole 97 as a starting point of bending.
Thereafter, as shown in FIG. 10B, the shaft hole 921 of the bearing portion 92 in the side wall 94 is opened at a desired distance d1 from the bearing surface 911 that contacts the valve stem portion in the bearing portion 91. Thus, the rocker arm 9 having a pair of side walls 94 is formed.
[0004]
[Problems to be solved]
However, the conventional method for manufacturing the rocker arm 9 has the following problems.
That is, when the bending process is performed, the portion 972 that protrudes inward from the bending line L that is the starting point of the bending becomes the protruding portion 923 on the base side 96 of the bearing portion 92 (see FIG. 10C). . That is, the protruding amount of the protruding portion 923 depends on the shape of the punched hole 97 and the width between the side walls 94 and becomes a value fixed by them.
For this reason, the distance d2 from the shaft hole 921 to the tip of the protruding portion 923 cannot be increased, and the protruding portion 923 may be weakened in strength (see FIG. 10B).
[0005]
The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a rocker arm manufacturing method capable of forming a rocker arm having high strength by flexibly deforming the shape of the rocker arm. .
[0006]
[Means for solving problems]
The invention according to claim 1 has a U-shaped cross section, a bearing portion provided with a pair of shaft holes for attaching the main shaft of the roller at the center portion, and a bearing portion for supporting the valve stem portion of the valve at one end. In the method for manufacturing a rocker arm, the other end is provided with a mounting portion that is attached to a pivot that is a pivot center.
A punching step of forming a piece of material into a developed shape of the rocker arm, forming a punched hole in the central portion of the developed shape, and forming a convex portion projecting inward from a bending line located on both sides of the punched hole;
Bending lines located on both sides of the punched hole are used as the starting point of bending, the material piece is bent into a U-shaped cross section , an intermediate body having a pair of side walls is formed , and the opening front side of the U-shaped cross section A U-bending step of forming, from the convex portion, a protruding portion that protrudes in a curved shape toward the base side opposite to
Pressurized in opposite directions the bearing portion located at the center portion and the said bearing portion and the mounting portion of both ends of the intermediate, deform the bearing portion toward the base side of the U-shaped section A pressure deformation step of moving and projecting the protrusion further toward the base side ;
A rocker arm manufacturing method comprising: a shaft hole forming step of drilling the shaft hole in the bearing portion in the pair of side walls .
[0007]
The most notable aspect of the present invention is that, in the pressure deformation step, the shaft hole is formed by pressing the bearing portion of the intermediate body and the support portions and the attachment portions at both ends in opposite directions. The position to be deformed is moved toward the base side opposite to the opening tip side of the U-shaped cross section.
[0008]
Next, the effects of the present invention will be described.
In forming the rocker arm, the U-shaped bending process is performed. In this U-shaped bending step, the material piece is bent into the U-shape to form an intermediate body having a pair of side walls.
Next, in the pressurizing and deforming step, the bearing portion positioned at the center portion of the intermediate body, and the support portions and the attachment portions at both ends thereof are pressed in opposite directions. At this time, the position where the shaft hole is formed in the bearing portion is deformed and moved toward the base side opposite to the distal end side of the U-shaped opening. That is, the portion on the base side of the bearing portion can be further protruded toward the base side.
[0009]
By the deformation movement, the distance from the position where the shaft hole is formed to the tip of the portion on the base side of the bearing portion can be increased in the bearing portion after the bending. Therefore, the strength of the bearing portion can be improved.
Therefore, according to the manufacturing method of the present invention, the rocker arm having high strength can be formed by flexibly deforming the shape of the rocker arm.
[0010]
Next , before the U-shaped bending step, a through hole (punching hole) is formed in the central portion of the material piece, and when the bending is performed in the U-shaped bending step, Both sides shall be the starting point of bending .
Thereby, when performing the bending, the bending resistance generated at the starting point of the bending is reduced, and the bending can be easily performed. Further, when the pressure is applied in the pressure deformation step, the pressure resistance is reduced, and the position where the shaft hole is formed can be easily deformed and moved.
[0011]
Next, after the above deform under pressure step, bored the shaft hole in the bearing portion of the pair of side walls.
Thereby, the shaft hole can be opened at an accurate position.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment A method for manufacturing a rocker arm according to an embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 1A to 1D, the method for manufacturing the rocker arm 1 in this example has a U-shaped cross section, and has a pair of shaft holes 121 to which the main shaft 211 of the roller 21 is attached at the center. A bearing portion 12 that guides the roller 21 is provided, a support portion 11 that supports the valve stem portion 31 of the valve 3 is provided at one end, and a mounting portion 13 that is attached to a pivot 44 serving as a rotation center is provided at the other end. The rocker arm 1 is manufactured.
[0013]
In manufacturing the rocker arm 1, first, a U-shaped bending process is performed in which the material piece 101 is bent in a U shape to form an intermediate body 103 having a pair of side walls 14.
Next, the bearing portion 12 positioned at the center portion of the intermediate body 103 and the support portions 11 and the mounting portions 13 at both ends thereof are pressed in opposite directions to determine the position where the shaft hole 121 is formed in the section U. A pressurizing and deforming step of deforming and moving toward the base side 16 opposite to the letter-shaped opening distal end side 15 is performed.
[0014]
This is described in detail below.
As shown in FIGS. 1A to 1D, the rocker arm 1 has a U-shaped cross section. Side walls 14 are formed at positions corresponding to both side portions of the U-shaped cross section, and the U-shaped cross section is formed. A support portion 11 and a mounting portion 13 are provided at a position corresponding to the bottom of the base plate. An opening hole 18 is provided between the support portion 11 and the attachment portion 13 at a position corresponding to the bottom portion.
The rocker arm 1 has a bearing portion 12 at the center portion of the side wall 14 between the support portion 11 and the mounting portion 13. In this bearing portion 12, a tip portion 122 which is a portion of the opening tip side 15 having a U-shaped cross section and a protruding portion 123 which is a portion of the base side 16 having a U-shape cross section have a convex curve. Yes.
[0015]
As shown in FIG. 2, the valve 3 that performs intake and / or exhaust of mixed gas or the like in the engine 6 is opened and closed by the driving force generated by the rotation of the cam 22 transmitted 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 441 of the pivot 44, and the support surface 111 of the support portion 11 pushes down the tip of the valve stem portion 31 of the valve 3 that contacts the support surface 111. Then, the valve 3 is opened. 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, the opening / closing operation of the valve 3 is performed.
[0016]
The mounting portion 13 of the rocker arm 1 is attached to the pivot 44 by screwing an adjusting screw 41 into a mounting hole 131 in which a female thread is cut, and fixing the screwing with a nut 42. A spring 43 is bridged between the mounting portion 13 and the pivot 44.
[0017]
Here, the shape of the mounting portion 13 can be various shapes. For example, as shown in FIG. 3 (a), a convex spherical pivot 44 is used, and the mounting portion 13 is formed into a concave spherical surface to be attached thereto. As shown in FIG. 3 (b), the boss of the mounting portion 13 is used. For example, the portion 131 is provided on the side opposite to the pivot 44 side.
Of course, the mounting hole 131 may be formed by welding a weld nut serving as the boss portion 131 to the through hole and screwing the adjusting screw 41 therethrough.
[0018]
Next, a method for manufacturing the rocker arm 1 will be described.
The rocker arm 1 in this example is formed by press working.
First, as a punching process, unnecessary portions of the flat plate-like material piece 101 are cut out by a punching die (not shown), and the material piece 101 is formed into a developed shape 102 of the rocker arm 1. At this time, the punched hole 17 is provided in the central portion of the developed shape 102 (see FIGS. 4A, 4B, and 4C).
A mounting hole 131 for the mounting portion 13 is formed.
[0019]
Next, as a U-shaped bending step, the material piece 101 is bent into a U-shape with bending lines L positioned at both side portions 171 of the punching hole 17 as the starting point of bending.
Thus, the intermediate body 103 having a U-shaped cross section and having a pair of side walls 14 is formed (see FIGS. 5A, 5B, and 5C).
[0020]
When the bending is performed, the protruding portion 172 (see FIG. 4A) protruding inward from the bending line L becomes the protruding portion 123 of the bearing portion 12 in the intermediate body 103 (see FIG. 5B). ). At this time, the punching hole 17 becomes the opening hole 18 (see FIG. 5A).
Next, as a support part forming step, the support surface 111 of the support part 11 is formed so as to have a convex curved surface by using a mold (not shown).
[0021]
Next, as a pressurizing deformation step, the bearing portion 12 at the center portion of the intermediate body 103 and the support portions 11 and the attachment portions 13 at both ends thereof are pressurized in opposite directions. At this time, the bearing portion 12 is deformed and moved in the direction of the base side 16 opposite to the opening tip side 15 having the U-shaped cross section, and the protrusion 123 is further protruded toward the base side 16. (See FIGS. 6A, 6B, and 6C).
Thereafter, as the shaft hole forming step, the shaft hole 121 is formed in the bearing portion 12 in the pair of side walls 14 (see FIGS. 7A, 7B, and 7C).
[0022]
Next, the pressure deformation process will be described in further detail.
As shown in FIGS. 8 (a) and 8 (b), in the pressurizing and deforming step, the first mold 51 and the support portion 11 that pressurize the tip 122 of the bearing portion 12 are used to perform the pressurization. A molding die 5 having a second molding die 52 that pressurizes and a third molding die 53 that pressurizes the mounting portion 13 is used.
[0023]
The first mold 51 has a guide groove 511 for applying pressure while guiding the front end portion 122 of the bearing portion 12.
In addition, the second molding die 52 has a tip surface 521 formed in a convex curved surface along the surface of the support portion 11 opposite to the support surface 111.
Further, the third mold 53 is formed in a flat shape so that the tip end surface 531 matches the plane of the mounting portion 13.
[0024]
In this example, the first mold 51 is fixed, the second mold 52 and the third mold 53 are stroked by a hydraulic cylinder (not shown), and the intermediate body 103 of the rocker arm 1 is pressurized.
Then, as shown in FIGS. 9A and 9B, when the second molding die 52 and the third molding die 53 are stroked, the bearing portion 12 is moved relative to the support portion 11 and the mounting portion 13. , And deforms and moves from the opening tip side 15 toward the base side 16.
[0025]
In this example, the support surface 111 of the support portion 11 is formed before the pressure deformation step as the support portion forming step. On the other hand, the bearing surface 111 may be formed at the same time as the bearing 12 is deformed and moved when the pressure is applied in the pressure deformation process.
[0026]
Next, the effect of this example will be described.
When bending is performed in the U-shaped bending step, the protruding portion 172 protruding inward from the bending line L becomes the protruding portion 123 of the bearing portion 12 in the intermediate body 103. Next, in the pressure deformation step, when the pressure is applied, the protrusion 123 can be further protruded toward the base side 16.
[0027]
And after making the protrusion part 123 protrude further in this way, the said shaft hole 121 is drilled in the said shaft hole formation process. Therefore, the distance d2 from the shaft hole 921 to the tip of the protruding portion 923 can be increased, and the strength of the protruding portion 123 in the bearing portion 12 can be improved. Therefore, the rocker arm 1 having high strength can be formed.
[0028]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a rocker arm manufacturing method capable of forming a rocker arm having high strength by flexibly deforming the shape of the rocker arm.
[Brief description of the drawings]
FIG. 1 is a diagram showing a rocker arm in an embodiment, (a) a perspective view, (b) a side view, (c) a plan view, and (d) a sectional view taken along line AA in (c).
FIG. 2 is an explanatory view showing a rocker arm mounting structure in the embodiment.
FIGS. 3A and 3B are diagrams showing a mounting portion of another rocker arm in the embodiment, wherein FIG. 3A is an explanatory diagram showing a concave spherical shape, and FIG. 3B is a diagram showing a boss portion provided on the side opposite to the pivot side.
FIGS. 4A and 4B are diagrams showing a punching process in the method for manufacturing a rocker arm in the embodiment, and FIG. 4A is a plan view, FIG. 4B is a cross-sectional view taken along line AA in FIG.
FIGS. 5A and 5B are diagrams showing a U-shaped bending process in a method for manufacturing a rocker arm in the embodiment, and FIG. 5A is a plan view, FIG. 5B is a cross-sectional view taken along line AA in FIG.
6A and 6B are diagrams showing a pressure deformation process in the method for manufacturing a rocker arm in the embodiment, and FIG. 6A is a plan view, FIG. 6B is a cross-sectional view taken along line AA in FIG.
7A and 7B are diagrams showing a shaft hole forming step in the method for manufacturing a rocker arm in the embodiment, and FIG. 7A is a plan view, and FIG. 7B is a cross-sectional view taken along line AA in FIG.
FIGS. 8A and 8B are diagrams showing an intermediate body before pressure deformation in a pressure deformation process in the embodiment, (a) a cross-sectional explanatory view, and (b) a side explanatory view.
9A and 9B are diagrams showing an intermediate body after pressure deformation in a pressure deformation process in the embodiment, (a) a cross-sectional explanatory view, and (b) a side explanatory view.
10A and 10B are diagrams showing a rocker arm in a conventional example, and FIG. 10A is a perspective view, FIG. 10B is a cross-sectional view taken along line AA in FIG.
[Explanation of symbols]
1. . . Rocker arm,
11. . . Bearing,
12 . . Bearing part,
13. . . Mounting part,
14 . . Side wall,
15. . . Opening tip side,
16. . . Base side,

Claims (1)

It has a U-shaped cross section, a bearing part with a pair of shaft holes for attaching the main shaft of the roller in the central part, a bearing part that supports the valve stem part of the valve at one end, and a rotation center at the other end In the manufacturing method of the rocker arm provided with a mounting portion that can be attached to the pivot to be
A punching step of forming a piece of material into a developed shape of the rocker arm, forming a punched hole in the central portion of the developed shape, and forming a convex portion projecting inward from a bending line located on both sides of the punched hole;
Bending lines located on both sides of the punched hole are used as the starting point of bending, the material piece is bent into a U-shaped cross section , an intermediate body having a pair of side walls is formed , and the opening front side of the U-shaped cross section A U-bending step of forming a protruding portion that protrudes in a curved shape toward the base side opposite to the above-mentioned protruding portion ;
Pressurized in opposite directions the bearing portion located at the center portion and the said bearing portion and the mounting portion of both ends of the intermediate, deform the bearing portion toward the base side of the U-shaped section A pressure deformation step of moving and projecting the protrusion further toward the base side ;
A method of manufacturing a rocker arm, comprising: a shaft hole forming step of drilling the shaft hole in the bearing portion on the pair of side walls .

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