JPH0724548A - Production of rocker arm for engine - Google Patents

Abstract

PURPOSE:To use by changing a part of the parts in a metallic mold at each processing and to reduce the number of the necessary parts in the metallic mold by commonly using the parts in the metallic mold except a punch, female die, stripper and counter in the parts in the metallic mold set in a general purpose pressing machine in order. CONSTITUTION:A shaping of a semiproduct which integrally forms four rocker arm shaping parts 1a-1d with a connecting part 2, is executed by a hot pressing. Successively, an outer peripheral trimming and a punching work to the rocker arm shaping parts 1a-1d integrally forming four pieces and a dividing work for dividing into two sets of the rocker arm shaping parts 1a, 1b and 1c, 1d and a side hole punching work and a side hole sizing work to each position are executed by the pressing. Further, a tapping work, a shearing work shearing to one by and a sizing work are executed by the pressing. At this time, the punch, female die, stripper and counter in the parts in the metallic mold which can not commonly be used in each process, are changed and each process is executed in order by using the general purpose pressing machine, and then, the number of the necessary parts is drastically reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a rocker arm for an engine and a production facility therefor.

[0002]

2. Description of the Related Art Conventionally, a push rod / rocker system in which a cam shaft is provided in a cylinder block and a valve is driven via a push rod and a rocker arm is known as a structural example of a typical valve operating system in a 4-cycle gasoline engine. And an overhead camshaft system in which a camshaft is arranged in a cylinder head and a valve is driven via a rocker arm or a lifter. In each case, since 4 to 6 rocker arms are used per cylinder, the production amount becomes very large.

However, as a method of processing the rocker arm for the engine, a predetermined rocker arm shape portion is manufactured by a hot hammer or a hot forging press, and then, horizontal hole boring processing, horizontal hole reaming processing, and milling machine at several places. After cutting such as end notch processing, vertical hole drilling, tapping, carburizing and quenching, polishing both ends of the center part, horizontal hole honing at several locations, and polishing of the notch. The process steps from the hot forging material to the completion of the rocker arm must go through a large number of steps as described above. Moreover, each process requires a large number of man-hours (processing time). In addition, although efforts have been made for a long time to rationalize and to automate the production line, the reduction of production cost in the current production method has already reached the limit, so it is not possible to improve productivity. There is.

Therefore, the applicant of the present invention can significantly reduce the processing time of the rocker arm by sequentially performing the processing using a general-purpose press machine instead of the cutting processing such as drilling, and thereby the manufacturing cost can be reduced. Proposal of a method for producing a rocker arm for an engine using a general-purpose press machine (June 3, 1993).
0-day patent application).

The rocker arms that are normally used in one cylinder of an engine are different in shape. Therefore, for example, when using four rocker arms per cylinder, four sets of dies are required, and a very large investment is required for the dies. To solve the problem, the applicant has made a set of metal molds by making the shape of each rocker arm shape part in one-sided mold different from that of one rocker arm. Since all kinds of rocker arms can be produced by the mold, and the mold cost can be suppressed,
At the same time, the above-mentioned patent application also proposes a rocker arm production method that can be used for small-scale production.

[0006]

However, the above-mentioned 1
Set the shape of each rocker arm in the surface mold to 1
According to the rocker arm production method for an engine, which is capable of producing all kinds of rocker arms 1 with one set of molds by forming different shapes corresponding to the shapes of different rocker arms of the cylinder, a small amount of Although it is possible to cope with it in production, it is necessary to provide a mold for each process because many processing steps have been taken, and still a large amount of investment is required for the mold. Therefore, there is a problem to be solved that the production cost per piece is high. The present invention has been made in order to solve the above problems, by sharing sharable mold parts, a non-sharable punch, a female die, a stripper, and a counter are replaced at each processing time. An object of the present invention is to provide a method for producing a rocker arm for an engine, which can drastically reduce the number of mold components required by using the rocker arm and can be produced at low cost.

[0007]

As a concrete means for solving the above problems, the present invention provides a semi-finished product in which a plurality of rocker arm-shaped portions are connected by a connecting portion,
A punching process is performed at a predetermined position of each rocker arm shape part, a division process of cutting the joint part into a predetermined number of pieces, and a part of the joint part is left, and the outer periphery of the rocker arm shape part of a predetermined number is punched. To perform trimming processing for pulling out, horizontal hole drilling processing and horizontal hole sizing processing to be applied to predetermined places, cutting processing for cutting the connecting part of the remaining part and dividing into each rocker arm shape part, and finishing sizing processing A method for producing a rocker arm for an engine is provided, wherein at least a punch, a female die, a stripper, and a counter are used in common among mold parts sequentially set in a general-purpose press. .

[0008]

According to the method of producing a rocker arm for an engine having the above-mentioned structure, a predetermined position of each rocker arm shape portion is provided with respect to a semi-finished product in which a plurality of rocker arm shape portions are connected by a connecting portion. Punching process, dividing process that cuts the connecting part into a predetermined number of pieces, trimming process that punches out the outer periphery of each rocker arm shape part for each pair, leaving a part of the connecting part, and applying to the predetermined place Lateral hole drilling and lateral hole sizing process, dividing process for dividing each rocker arm shape part, and finishing sizing process, punches, female dies, strippers, and die parts that cannot be shared at each processing time, The counter is exchanged and the operation is sequentially performed by a general-purpose press machine. Therefore, the required number of mold parts can be significantly reduced, and the cost required for the mold can be reduced, so that there is an excellent effect that the manufacturing cost can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for producing an engine rocker arm of the present invention will be described with reference to the accompanying drawings. 1 in 4
It is a top view showing the state where the individual rocker arm shape parts were integrally molded. FIG. 2 is a cross-sectional view of the rocker arm shaped portion integrally formed. FIG. 3 is a process diagram showing the processing temperature and the number of machining steps in each process. In this embodiment, as shown in FIG. 3, four rocker arm-shaped portions 1a to 1d are integrated by a connecting portion 2 in a die having one surface, and a semi-finished product having a prepared hole is formed. Is performed by a hot forging press. Subsequently, outer periphery trimming and hole punching are performed on the rocker arm shaped portions 1a to 1d in which four pieces are integrated, and the rocker arm shaped portions 1a to 1d.
d, rocker arm shaped portions 1a and 1b and 1c and 1d
And the horizontal hole sizing and the horizontal hole sizing for the rocker arm shaped portions 1a and 1b and 1c and 1d, respectively. Subsequently, tapping is performed by a tapping machine to divide the rocker arm shaped portions 1a and 1b and 1c and 1d into one piece, and finish sizing processing for each of the divided rocker arm shaped portions 1a to 1d. By press working. Then heat treatment and carburizing and quenching,
It is completed by performing inner diameter polishing and inner diameter honing. Then, the punch 51, the female die 52, the stripper 53, and the counter 54, which cannot be shared for each processing, are exchanged to perform each processing.

FIG. 8 is a cross-sectional view showing a common mold part. The upper die assembly 20, which is an upper mold, is provided with a shank 21, an upper die base 22, four hollow cylindrical slide guides 23, a punch plate 24, and a punch holder 27, which are screwed to each other. Are assembled together. The punch plate 24
A counter insertion hole 25 and a counter guide recess 26 are provided in the. In the lower die assembly 30, which is a lower mold, a knockout guide 33 having a knockout guide recess 34 is attached to the center of a lower die base 31, and two die plates 35 and 36 having knockout insertion holes 41 are provided above the knockout guide 33. The die holder 37 having the knockout insertion hole 41 and the die mounting recess 42 is provided on the upper portion thereof, and the die holder 37 is screwed to be integrally assembled. In addition, four guide posts 32 are provided at positions corresponding to the slide guides 23 so that the slide guides 23 can be inserted into the four corners. Further, the knockout insertion hole 41 and the knockout guide recess 3
The knock-out pin 40 and the knock-out disc 39 are slidably inserted into the respective parts 4. Then, the knockout disk 39 is pressed upward by the cushion pin 38 which is pressed by a spring or a cylinder (not shown). The upper die assembly 20 and the lower die assembly 30 configured as described above are commonly used for the respective processes and are not replaced.

Next, the operation of each step will be described in detail. FIG. 9 shows each processing performed by press processing, a plan shape,
It is explanatory drawing which shows the relationship of the metal mold components replaced. First, in the first step, the rocker arm blank 1 is formed by cutting the round bar steel material into a predetermined volume corresponding to four pieces at room temperature. Then, in the second step, 1000 to 1 Celsius
After being heated to 200 degrees, as shown in FIG. 10, a punch 51 is attached to the upper die assembly 20, a female die 52 is attached to the lower assembly 30, and hot forging is performed. By the hot forging process, as shown in FIG. 1, four rocker arm shaped portions 1a to 1d having the same shape,
A joint portion 2 for connecting the rocker arm-shaped portions 1a to 1d is simultaneously formed. At this time, flash 3 is generated on the outer peripheral portion. Since the four rocker arm-shaped portions 1a to 1d are integrated by the connecting portion 2, the third to fifth steps of the next step are performed.
In the process, the positional relationship among the rocker arm-shaped portions 1a to 1d is accurately maintained, and shake or rattling does not occur. Therefore, the dimensional accuracy of molding is improved.

As shown in FIG. 11, the trimming process of the third step is performed by punching the upper die assembly 20 with the punch 51,
The stripper 53 and the spring 55 are attached, the female die 52 is attached to the lower assembly 30, and the burrs 3 on the outer peripheral portion are removed while being heated to 1000 to 1200 degrees Celsius. In addition, sizing processing is also performed at the same time to correct the deformation of the shape of the rocker arm 1 due to the increase in friction with the mold due to heat.
Subsequently, in the fourth step, as shown in FIG. 12, a punch 51 having a punching pin 56 provided on the upper die assembly 20, a stripper 53, and a spring 55 are attached to the side surfaces of the rocker arm-shaped portions 1a to 1d, A female die 52 is attached to the lower assembly 30, and the round hole 4 and the square hole 5 are processed in a heated state of 600 to 800 degrees Celsius. The round holes 4 and the square holes 5 are first processed by press working a prepared hole having a diameter or width of about 0.5 to 5 mm smaller than the instructed processing dimension, and then processed to the instructed processing dimension by sizing. Further, in order to cleanly finish the round hole 4 and the square hole 5, the punching pin 56 is formed in a taper shape, and the corner portion of the tip is rounded.

By the above steps, the machining of the flat surface portions of the rocker arm shaped portions 1a to 1d is completed. Next, it is necessary to remove the connecting portion 2 before processing the side surface portions of the rocker arm-shaped portions 1a to 1d. Therefore, the rocker arm-shaped portions 1a to 1d are paired with the rocker arm-shaped portions 1a, 1b and 1c at a temperature of 200 to 800 degrees Celsius by the two-division processing in the fifth step as shown in FIG.
And 1d. After that, a part 2a of the connecting portion 2
As shown in FIG. 13, the boss 57 is attached to the upper die assembly 20 as shown in FIG. Provided punch 51, stripper 53,
This is performed by a mold in which a counter 54 and a spring 55 are attached and a female die 52 is attached to the lower assembly 30. Female die 52 for performing the trimming process
As shown in FIG. 5, the inlet corner portion 58 is provided with an R chamfer or a tapered portion to prevent burrs from being generated. Also,
At this time, the clearance between the female die 52 and the boss 57 is
It is set to about 0.2 to 2% of the thickness of the rocker arm shaped portions 1a to 1d to be punched. By performing these processing steps, the side surface of the rocker arm-shaped portion 1 is finished with a beautiful surface, and at the same time, it can be processed with high accuracy during hot and warm processing. In the case where the thickness of the rocker arm shaped portions 1a to 1d to be processed is 20 mm,
It can be manufactured with a dimensional error of 0.05 mm or less.

Then, at a temperature of 200 to 600 degrees Celsius, a sixth step of forming a horizontal hole is as shown in FIG. 14, in which the punch 5 in which the upper die assembly 20 is provided with a punching pin 58.
1, attach the stripper 53, and the spring 55,
It is performed by a die having a female die 52 attached to the lower assembly 30. Horizontal holes 6 are simultaneously formed in the rocker arm-shaped portions 1a and 1b and 1c and 1d which are divided by the two-division processing and are paired as shown in FIG.
To provide. In this case, machining is performed with a machining allowance of about 0.05 to 2 mm in diameter with respect to the machining instruction dimension. Further, the horizontal holes 6 of the rocker arms 1a to 1d are generally of one-hole type and two-hole type, but if the two-hole type is close to each other, the The hole is formed in this step and the other hole is formed in the next step to prevent the strength of the mold from being lowered. As shown in FIG. 7, the punching pin 58 at the time of machining the horizontal hole is provided with an R chamfer or a taper portion at a corner portion 59. As a result, the inner wall surface of the lateral hole 6 after processing is finished smoothly, so that it is possible to prevent the inner wall surface of the lateral hole 6 from being scratched, chipped, or broken during the lateral hole sizing process in the next step.

Next, at a temperature of 200 to 600 degrees Celsius,
As shown in FIG. 15, the horizontal hole sizing process, which is a process, is performed on the upper die assembly 20 by sizing pins 60.
The punch 51 provided with the above, the stripper 53, and the spring 55 are attached, and the female die 5 is attached to the lower assembly 30.
It is carried out by a mold attached with 2. Two pieces are machined at the same time as in the case of the lateral hole machining. A machining allowance having a diameter of about 0.05 to 2 mm of the lateral hole machined by the lateral hole machining is sized. In this case, the rocker arm shape part 1
In order not to destroy the outer shapes of a to 1d, the female die 52 and the stripper 53 of the mold are provided with recesses having the same shape as the rocker arm shape portion 1. Subsequently, tapping, which is the eighth step, is performed on the state in which the two rocker arm-shaped portions 1a to 1d are united in the cold state. In this step, two integrated rocker arm-shaped portions 1a and 1b or 1c and 1d are simultaneously machined by a biaxial tap by a general tapping machine.

Then, as shown in FIG. 16, the four-division processing, which is the cutting processing in the ninth step, includes a punch 51 provided with a punching plate 61 on the upper die assembly 20, a stripper 53, a counter 54, and a spring 55. attachment,
It is performed by a die having a female die 52 attached to the lower assembly 30. Thereby, the two rocker arm-shaped portions 1a and 1b and the part 2a of the connecting portion 2 that connects 1c and 1d are punched out into four independent rocker arm-shaped portions 1a, 1b, 1c and 1d. Divided. The four-division processing is performed by the female die 52 and the stripper 53 which are set so as not to destroy the already finished shape of the rocker arm shaped portions 1a to 1d as in the case of the horizontal hole sizing processing. Square hole 5 in the flat part, sandwiching one of
Also, a pilot pin (not shown) is inserted into the lateral hole 6 and the pressing is performed.

Then, in the tenth step, the rocker arm shaped portions 1a, 1b, 1c and 1d divided into four are shown in FIG. 17 in a cold press for the purpose of improving accuracy and final finishing with a general-purpose press machine. As mentioned above, the upper die assembly 2
A punch 51, a stripper 53, a counter 54, and a spring 55 are attached to 0, and a finish sizing process is performed by a die in which a female die 52 is attached to the lower assembly 30. In this case, the mold structure uses a cam (not shown) to simultaneously correct the shape, hole diameter, etc., with one stroke of the press machine. As a result, the rocker arm 1 with high accuracy is manufactured by slightly improving the accuracy in anticipation of quenching distortion in the next step. Therefore, even if the rocker arm 1 is mass-produced, it can always be manufactured with high accuracy. Then, the heat treatment and the carburizing and quenching process are performed in the 11th process, the inner diameter polishing process is performed in the 12th process, and the inner diameter honing process is performed in the 13th process to complete the process.

In this embodiment, four molds are formed on one surface of the mold, but the present invention is not limited to this. In the multi-cavity processing of a die on one surface, the higher the number of simultaneous machining is, the higher the productivity is, but at the same time, the difficulty in producing the die is increased and the strength of the die is also a problem. Further, it is necessary to consider not only hot forging but also cold pressing thereafter. Therefore, in consideration of the shape of the rocker arm 1 to be produced, the degree of processing difficulty, the production quantity, etc., a die for taking one piece to about six pieces is determined.

Further, in this embodiment, the rocker arms 1 manufactured on one surface of the mold have the same shape.
On the other hand, it is also possible to have different shapes corresponding to the shapes of the separate rocker arms 1 of one cylinder.
In this case, all types of rocker arms 1 can be produced with one set of molds, so that the mold cost can be suppressed. Therefore, in consideration of the points described above, when the rocker arm 1 is produced, the number of products to be taken by the one-sided die, and whether the same type is produced by the one-sided die or different types are produced. Decide whether to produce.

According to the above-described embodiment, since the mold for the rocker arm for the engine can be incorporated into the general general-purpose press device, no special device is required. It is also possible to incorporate it into a general-purpose press device and integrate it into a dedicated processing device for an engine rocker arm. Further, by using a mold in which parts are exchanged according to each processing, the general-purpose press device can be implemented by only one unit.

[Brief description of drawings]

FIG. 1 is a plan view showing a state in which four rocker arm-shaped portions of the present invention are integrally molded.

FIG. 2 is a sectional view showing a rocker arm-shaped portion in FIG.

FIG. 3 is a process diagram showing each process, a processing temperature, and the number of processed pieces.

FIG. 4 is a plan view showing a rocker arm-shaped portion after being divided into two.

FIG. 5 is a cross-sectional view showing a female die that performs two-division processing.

FIG. 6 is a side view showing a state in which a lateral hole is processed.

FIG. 7 is a cross-sectional view showing a punch at the time of processing a horizontal hole.

FIG. 8 is a cross-sectional view showing an outline of a common mold component.

FIG. 9 is an explanatory diagram showing a relationship between each process performed by press working, a planar shape, and a die part to be replaced.

FIG. 10 to FIG. 17 are cross-sectional views schematically showing a mold in which parts are exchanged for each processing.

[Explanation of symbols]

 1 ... rocker arm material, 1a-1d ... rocker arm shape part, 2 ... connecting part, 3 ... flash part, 4 ... Round hole, 5 ... Square hole, 6 ... Horizontal hole 51 ... Punch, 52 ... Female die, 53 ... Stripper, 54 ... Counter

Claims (1)

[Claims] 1. A semi-finished product in which a plurality of rocker arm-shaped portions are connected by a connecting portion, and punching at predetermined positions of each rocker arm-shaped portion, and cutting the connecting portion for each predetermined number. Dividing into two parts, trimming to punch out the outer periphery of each predetermined number of rocker arm shaped parts with a part of the connecting part left, lateral drilling and lateral hole sizing to be applied at a predetermined position, and joining of the remaining part At least a punch, a female die, a stripper, and a counter among the die parts that are sequentially set in a general-purpose press in order to perform a cutting process for cutting a rocker arm shape part and a finishing sizing process. A method for producing a rocker arm for an engine, characterized in that mold parts other than the above are commonly used.