JPH11210418A - Manufacture for rocker arm and manufacturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacture for a rocker arm certainly forming a pair of shaft fixing holes coaxially while improving production efficiency and reducing a cost. SOLUTION: In this manufacture of a rocker arm, after a rocker arm main body 11 equipped with a pair of both side walls 21 arranged in parallel and connecting walls connecting these both side walls 21 to each other is manufactured by executing outside diameter punching and folding to a metallic plate, the both side walls 21 of the rocker arm main body 11 are punched out simultaneously from the outside by a pair of boring punches so as to form simultaneously shaft fixing holes 26 in the both side walls 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a rocker arm for opening and closing a valve in, for example, a valve train of an internal combustion engine of a vehicle.

[0002]

2. Description of the Related Art FIG. 6 is a sectional view showing a valve operating mechanism in an internal combustion engine of a vehicle or the like. As shown in the figure, the valve operating mechanism includes a cam (3) that rotates in conjunction with a crankshaft (2) and a cam (3) that rotates by a valve (4) such as an intake valve or an exhaust valve.
A rocker arm (1) is provided for converting the reciprocating motion of the valve stem (5).

As shown in FIGS. 6 and 7, the rocker arm (1) has a pair of side walls (1) arranged in parallel.
a), connecting walls (1b) and (1c) connecting one end and the other end between the two side walls, and a valve provided on the connecting wall (1b) on one end and abutting on the valve stem (5). It has a stem contact portion (1d) and a pivot engaging portion (1e) provided on the other end side connecting wall (1c) and engaged with a pivot portion (6) fixed to the cylinder head. Further, on both side walls (1a) of the rocker arm (1), shaft fixing holes (1f) are provided coaxially with each other. The shaft fixing holes (1f) are provided with support shafts (8) for the rollers (7). ) Is fixed, so that the roller (7) and the cam (3) can be in rolling contact with each other.

Since such a rocker arm (1) requires sufficient rigidity and has a complicated shape, it is generally manufactured by forging or precision casting (lost wax).
Further, after forming a hole for a shaft fixing hole with a drill or the like in the forged product or cast article, the hole is subjected to machining such as reamer processing as necessary to form a shaft fixing hole (1f). Like that.

[0005]

However, the above-mentioned method of manufacturing a rocker arm requires low-efficiency machining, such as drilling, which leads to a reduction in production efficiency and an increase in cost. was there.

On the other hand, in recent years, as the rotation speed and the output of the internal combustion engine have been increased, it has been desired to reduce the weight of the rocker arm in order to reduce the inertial weight. Many have been proposed.

When a rocker arm is manufactured by pressing, a rocker arm body having a predetermined shape is manufactured by performing an outer diameter punching process and a bending process on a steel plate, and a drill or the like is formed on both side walls of the rocker arm body. 8 to obtain a rocker arm by forming a shaft fixing hole, and FIG.
As shown in FIG. 9, when the outer diameter is removed from the steel sheet, a shaft fixing hole (1f) is also formed at the same time, and the hole (1f) is arranged on the coaxial line as shown in FIG. It is well known that the rocker arm (1) is obtained by bending.

However, in the former method using a drill or the like, the production efficiency is low and the cost still increases.

In the latter outer diameter punching process, the shaft fixing hole (1
In the method in which f) is formed, the shaft fixing holes (1f) are displaced from each other when bent, and it is difficult to arrange the shaft fixing holes on a coaxial line. However, there arises a problem that the positional accuracy cannot be sufficiently secured.

The present invention solves the above-mentioned problems of the prior art, improves the production efficiency and reduces the cost, and can sufficiently secure the positional accuracy between the pair of shaft fixing holes.
An object of the present invention is to provide a method and an apparatus for manufacturing a rocker arm to which a roller support shaft can be attached in a stable state.

[0011]

In order to achieve the above object, a method for manufacturing a rocker arm according to the present invention comprises a rocker arm having a pair of side walls arranged in parallel and a connecting wall connecting the both side walls. A step of obtaining a main body, and in a state in which a punch for punching is arranged inside both side walls of the rocker arm main body, a pair of punches for punching which are arranged coaxially opposite each other, so that predetermined regions of the both side walls are outside. And a step of simultaneously forming roller support shaft fixing holes in both side walls.

In the method of manufacturing a rocker arm according to the present invention, both side walls of the rocker arm body are simultaneously punched by a pair of punches for forming holes on the same axis to form a roller support shaft fixing hole. Therefore, the pair of shaft fixing holes can be accurately formed on the coaxial line. In addition, since the punching pressure acting on the rocker arm main body is evenly applied from both sides in a well-balanced manner, it is possible to effectively prevent adverse effects due to the punching pressure.

[0013] Also, compared with drilling and the like,
In addition to efficient processing, the processing can be performed more efficiently than in the case where the shaft fixing holes are separately formed on each side.

In the present invention, a chamfered portion is formed on the outer periphery of the base end portion of the punch for punching, and when the punch is driven, the periphery of the hole is pressed by the chamfered portion to crush and deform. Is desirable.

That is, in this case, since it is not necessary to form the chamfered portion in a separate step, the chamfered portion can be formed while maintaining high production efficiency, and the end portion of the roller support shaft inserted into the shaft fixing hole can be formed. When swaged to an enlarged diameter, the swaged end can be sufficiently pressed against the chamfered portion,
The fixing force of the roller support shaft can be further improved.

Further, when the surface pressing portion is formed, even if the punching timing of the pair of punches is shifted, an adverse effect due to the punching pressure can be avoided.
For example, in the case where the surface pressing portion is not formed on the punch, immediately after the side wall of the rocker arm main body is punched by the punch, the punch driving load applied to the punching die becomes “0”. If it is misaligned, the driving load is applied from one side and the die may be damaged. However, when forming a surface pressing portion on a punch, even after punching with a punch,
Since the surface pressing load is applied to the die by the surface pressing part, even if the punching timing of the left and right punches is shifted, the die is supported by the surface pressing load, so it is possible to reliably prevent defects such as breakage of the die. Can be prevented.

Further, in the present invention, after the roller support shaft fixing holes are formed on both side walls of the rocker arm main body,
It is preferable that the relative position between the rocker arm main body and the punching die is shifted to discharge the scraps in the punching die.

That is, in this case, scraps in the die for punching can be discharged without any trouble, and continuous processing becomes possible.

On the other hand, according to the rocker arm manufacturing apparatus of the present invention, a roller support shaft fixing hole is formed in both side walls of a rocker arm body having a pair of side walls arranged in parallel and a connecting wall connecting the both side walls. A rocker arm manufacturing apparatus for forming a, in a mode to be fitted between both side walls of the rocker arm body, a hole-forming die capable of setting the rocker arm, on both sides of the hole-forming die,
A pair of punches for punching, which are disposed on the same axis and coaxial with each other, corresponding to both side walls of the rocker arm main body, and wherein the rocker arm is set on the die for punching, and the pair of punches are punched. The gist of the present invention is configured such that predetermined regions of both side walls can be simultaneously punched out from the outside by a punch to form the roller support shaft fixing hole.

This apparatus invention specifies an apparatus suitable for carrying out the above-mentioned manufacturing method invention.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing a rocker arm according to an embodiment of the present invention will be described in detail with reference to the drawings.

In the present manufacturing method, first, as shown in FIG. 1, a predetermined region of a steel plate is punched to obtain a punched product (10) having a predetermined shape.

Subsequently, as shown in FIG. 2, the punched product (10) is bent to obtain a rocker arm body (11).

The rocker arm body (11) has a pair of side walls (21) arranged in parallel with each other, and a connecting wall (22a) connecting one end and the other end between the two side walls.
(22b), a valve stem contact portion (23) provided on one end side connection wall (22a) and abutting against a valve stem (see FIG. 6), and a cylinder head provided on the other end side connection wall (22b). And a pivot engaging portion (24) that engages with a pivot portion (see FIG. 6) fixed to the arm.

Next, a shaft fixing hole is formed on both side walls (21) of the rocker arm body (11) thus obtained by using a hole punching device (rocker arm manufacturing device) described in detail below.

That is, the drilling device of the present embodiment is similar to that of FIG.
And as shown in FIG. 4, it has a mounting table (31),
A hole forming die (32) having a width corresponding to a size between both side walls of the rocker arm main body (11) is provided on the mounting table (31). In addition, the installation table (3
1) A positioning projection (33) that can be engaged with the pivot engagement portion (24) of the rocker arm body (11) is provided on the upper side. Then, a hole forming die (32) is fitted in the center between both side walls (21) of the rocker arm body (11) so that the pivot engaging portion (24) is engaged with the positioning protrusion (33). Thereby, the rocker arm body (11) is configured to be installed at a predetermined position on the installation table (31).

In the hole forming die (32), the die hole (32a) penetrates in the width direction corresponding to the shaft fixing hole forming position on both side walls (21) of the rocker arm body (11). Is formed.

The drilling device also includes an installation table (31)
Punch supports (35) are arranged on both sides of the
Each punch support (35) is provided with the above-mentioned punching die (3).
A punch for punching (36) is slidably supported in the axial direction on a coaxial line via a punch support member (37). Further, on both sides of the punch support table (35), an elevating driver (38) that can be driven up and down is arranged. A cam surface (38a) provided at the lower end of the elevating driver (38) and a punch A cam surface (37a) provided on the base end side of the support member (37) is slidably abutted and arranged. When the lifting drive (38) is driven to descend, the punch for punching (36) is configured to advance in the axial direction.

On the outer periphery of the base end side of the punch (36),
A tapered surface pressing portion (39) is formed for forming a chamfered portion.

In order to form a shaft fixing hole in the rocker arm main body (11) by the hole punching device having the above configuration, first, the rocker arm main body (11) is set on the mounting table (31) as described above. Then, the lift (38) is lowered to advance the punch (36). As a result, FIG.
As shown in the figure, predetermined regions of both side walls (21) of the rocker arm body (11) are punched out from both sides at the same time, and shaft fixing holes (26) arranged coaxially with each other are formed in both side walls (21). Is done.

Also, during punching, when the punch (36) is driven, the surface pressing portion (39) on the base end side of the punch presses the periphery of the open end of the rocker arm body (11). It is crushed and deformed, and a chamfer (27) is formed along the periphery.

In the punching device of the present embodiment, the rocker arm main body (11) is set on the punching die (32) after both side walls (21) of the rocker arm main body (11) are punched out. In the state, the installation table (31)
Along with the punching die (32), it slides in the horizontal direction and moves to the discharge stage. Then, the rocker arm body (11) is pushed up from below by a pushing-up mechanism (not shown) and is taken out of the die (32). afterwards,
A protruding pin (not shown) is inserted into the die hole (32a) from one side along the axial direction, and the die hole (32a) is inserted.
The scraps in a) are discharged to a predetermined location.
When the ejection of the scraps is completed, the installation table (31) slides back to the original position, a new rocker arm body is installed, and the punching is performed in the same manner as described above.
In this way, the drilling of the rocker arm main body is performed sequentially and sequentially, and the rocker arms are sequentially manufactured.

As described above, in this embodiment, both side walls (21) of the rocker arm main body (11) are formed by a pair of punches (36) arranged coaxially.
Punched from both sides at the same time, the shaft fixing holes (2
6), a pair of shaft fixing holes (2) are formed.
6) can be accurately arranged on a coaxial line, and mutual positional accuracy can be sufficiently ensured. For this reason, the support shaft of the roller can be stably mounted in the shaft fixing hole (26), and it is possible to reliably prevent problems such as removal of the roller support shaft from occurring.

Further, since the pressure at the time of the driving is uniformly applied from both sides in a well-balanced manner, it is possible to reliably prevent the die (32) and the processed product from being harmfully deformed by the punching pressure. . Furthermore, compared to the case where the shaft fixing holes (26) are separately formed on each side, the processing efficiency of the drilling process can be improved, and the production efficiency can be further improved.

Further, in this embodiment, since the boring is performed sequentially and continuously, a higher production efficiency can be obtained.

In this embodiment, the chamfered portion (2) is formed on the periphery of the opening of the shaft fixing hole (26) in the rocker arm.
7), when the roller support shaft is inserted into the shaft fixing hole (26) and the end of the roller support shaft is caulked to an enlarged diameter, the end of the roller support shaft is chamfered ( 27), the fixing force of the roller support shaft can be further improved, and problems such as detachment of the roller support shaft can be more reliably prevented.

Further, since the chamfered portion (27) is formed at the same time as the boring process, the chamfering process is performed.
There is no need to perform this step separately, and high production efficiency can be maintained.

In addition, a punch (39) is provided on the punch (36).
Thus, even if the punching timing of the pair of punches (36) is shifted, adverse effects due to the punching pressure can be avoided. That is, the punch (36)
When the surface pressing portion is not formed, the punching load applied to the punching die (32) immediately after the side wall (21) of the rocker arm body (11) is punched by the punch (36) is "0". So, tentatively left and right punch (36)
If the punching timing is shifted, the driving load is applied from one side, and the die (32) and the like may be damaged. However, in the case where the surface pressing portion (39) is formed on the punch (36), a surface pressing load is applied to the die (32) by the surface pressing portion (39) even after punching by the punch (36). Left and right punches (36)
Even if the punching timing of the die is shifted, since the die (32) is supported by the surface pressing load, it is possible to reliably prevent problems such as breakage of the die (32).

Here, as shown in FIG.
7) The chamfer amount (L2) is the thickness (T) of the side wall (21).
Is preferably set to 10 to 30%. In other words, if the chamfer amount (L2) is too small, the amount of press-contact of the support shaft to the chamfered portion (27) when the roller support shaft is crimped and fixed becomes small, and the fixing force of the roller support shaft may not be sufficiently secured. There is. Conversely, if the amount of chamfering (L2) is too large, the amount of crushing around the shaft fixing hole (26) will increase, causing burrs to protrude to the periphery or harmful deformation, and the trueness of the shaft fixing hole (26). Roundness may be reduced.

In the above embodiment, the case where the rocker arm main body is obtained by pressing such as outer diameter punching and bending is described. However, the present invention is not limited to this. For example, forging and precision casting ( The rocker arm body may be obtained by lost wax), and the shaft fixing hole may be formed in the rocker arm body as described above.

Further, in the present invention, after the shaft fixing hole is formed in the rocker arm main body, a mechanic such as reaming may be performed.

In the present invention, it is not always necessary to form the chamfered portion. Needless to say, the formation of the chamfered portion does not have to be performed at the same time as the drilling process.

In the above embodiment, after the both side walls (21) of the rocker arm body are punched by the punch (36), the rocker arm body (11) is moved to the discharge stage together with the punching die (32). Although the scraps in the die hole are discharged, the present invention is not limited to this. After punching both side walls (21), the die (32) and the rocker arm body (11) are not moved, and In the original processing stage, the scrap may be discharged.

In the above embodiment, the rocker arm body (11) is moved relative to the die (32) at the discharge stage to discharge the scraps in the die hole. However, the present invention is not limited to this. Not die (32)
May be moved downward, for example, with respect to the rocker arm body (11) to discharge the scraps. In short, the relative position between the die (32) and the rocker arm body (11) is shifted, Discharging the scrap in the die By this means, the scrap can be reliably discharged.

[0045]

EXAMPLE A steel plate was subjected to an outer diameter punching process and a bending process to produce a bent product (rocker arm body) having a side wall having a thickness of 3.5 mm.

The rocker arm body is formed with shaft fixing holes on both side walls using the same drilling device as in the above embodiment, and the shaft fixing holes are subjected to reaming to finish the inner surface of the hole. Was done.

In the rocker arm thus obtained, a pair of shaft fixing holes formed on both side walls thereof are accurately arranged on a coaxial line, and have high positional accuracy between each other. Further, the inner surface of the shaft fixing hole was formed on a good surface having a small surface roughness.

[0048]

As described above, according to the method of manufacturing a rocker arm of the present invention, both side walls of the rocker arm body are simultaneously punched out by a pair of punches for making holes facing each other on a coaxial line. Since the fixing holes are formed, the pair of shaft fixing holes can be formed accurately on the coaxial line, and the positional accuracy between them can be sufficiently ensured. Therefore, the roller support shaft can be stably mounted in the shaft fixing hole, and it is possible to reliably prevent a problem such as removal of the roller support shaft from occurring. In addition, since the punching pressure acting on the rocker arm main body is evenly applied from both sides in a well-balanced manner, it is possible to effectively prevent adverse effects due to the punching pressure. Furthermore, compared to the case where holes are formed by machining such as drill cutting, machining can be performed more efficiently. In addition, compared to the case where shaft fixing holes are formed separately for each side, machining can be performed more efficiently, improving production efficiency. There is an effect that can be achieved.

In the present invention, when a chamfered portion is formed on the outer periphery of the base end of the punch for punching and the chamfered portion is formed simultaneously with the punching, it is not necessary to form the chamfered portion in a separate step. Further, the fixing force of the roller support shaft can be further improved by the chamfered portion while maintaining high production efficiency. In addition, when the surface pressing portion is formed, even after the punching by the punch, the surface pressing load is applied to the die by the surface pressing portion. Since it is supported, there is an advantage that adverse effects such as breakage of the die due to the punching pressure can be more reliably prevented.

Also, in the present invention, when the position of the rocker arm main body and the hole forming die is shifted after forming the roller support shaft fixing hole to discharge the chippings in the die, the chips in the die are surely removed. The drilling process can be performed successively and continuously, and the production efficiency can be reduced.
There is an advantage that it can be further improved.

On the other hand, the rocker arm manufacturing apparatus according to the present invention specifies an apparatus suitable for carrying out the above-described manufacturing method, and the same effects as described above can be obtained.

[Brief description of the drawings]

FIG. 1 is a view showing a punched product as an intermediate product in a method of manufacturing a rocker arm according to an embodiment of the present invention, wherein FIG. 1 (a) is a sectional view and FIG. 1 (b) is a plan view. .

FIGS. 2A and 2B are views showing a rocker arm main body as an intermediate product in the method of the embodiment, wherein FIG. 2A is a sectional view and FIG. 2B is a plan view.

FIG. 3 is a sectional view showing a hole punching device used in the method of the embodiment.

FIG. 4 is a perspective view showing an installation table in the hole punching device of the embodiment.

FIG. 5 is an enlarged cross-sectional view showing the vicinity of a shaft fixing hole of the rocker arm main body immediately after drilling in the method of the embodiment.

FIG. 6 is a sectional view showing a valve mechanism of an internal combustion engine in a vehicle.

FIG. 7 is a perspective view showing a conventional rocker arm.

8A and 8B are views showing a punched product as an intermediate product in the conventional method, wherein FIG. 8A is a sectional view and FIG. 8B is a plan view.

9A and 9B are views showing a rocker arm obtained by conventional press working, wherein FIG. 9A is a cross-sectional view and FIG.
Is a plan view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Rocker arm main body 21 ... Side wall 22a, 22b ... Connecting wall 26 ... Shaft fixing hole 27 ... Chamfering part 32 ... Drilling die 36 ... Drilling punch 39 ... Surface pressing part

Claims (4)

[Claims] 1. A step of obtaining a rocker arm main body having a pair of side walls arranged in parallel and a connecting wall connecting the both side walls, and forming a hole forming die inside both side walls of the rocker arm main body. A step of simultaneously punching predetermined regions of the side walls from outside with a pair of hole punches disposed coaxially facing each other in the arranged state, and simultaneously forming roller support shaft fixing holes in both side walls. Rocker arm manufacturing method. 2. A chamfered portion in which a punched portion is formed on the outer periphery of a base end portion of the punch for punching, and when punching is performed, the periphery of the hole is pressed by the chamfered portion to be crushed and deformed. The method for manufacturing a rocker arm according to claim 1, wherein 3. After forming a roller support shaft fixing hole on both side walls of the rocker arm main body, a relative position between the rocker arm main body and the hole forming die is shifted to remove a scrap in the hole forming die. The method for manufacturing a rocker arm according to claim 1 or 2, wherein the rocker arm is discharged. 4. A rocker arm manufacturing apparatus for forming a roller support shaft fixing hole in both side walls of a rocker arm body having a pair of side walls arranged in parallel and a connecting wall connecting the both side walls. And a pair of piercing dies that can be arranged on the inside of both side walls of the rocker arm main body, and a pair of piercing punches arranged on both sides of the piercing die on the same axis. In a state where the perforating dies are arranged inside both side walls of the rocker arm, a predetermined area of each of the side walls can be simultaneously punched from the outside by the pair of perforating punches to form the roller support shaft fixing hole. An apparatus for manufacturing a rocker arm, comprising: