JPS633699B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for manufacturing an operating rod used to operate an automobile brake booster, which has become widely used in recent years.

Conventionally, the operating rod was directly connected to a clevis installed above the foot plate of the brake pedal, and the operating rod was threaded and connected to the clevis, and when the brake pedal was depressed, the plunger valve built into the brake booster was activated. It is used to activate the brakes and make the brakes more effective. A typical example of the operating rod 1 will be explained with reference to FIG. 1.Although not shown, it has a threaded portion 2 for screwing and connecting with the clevis, a knurled portion 3 that makes it easy to turn by hand during screwing, and a shaft portion 4. A spherical portion 7 is formed inseparably at the tip of the collar portion 5 and the thin shaft portion 6 (on the right side in FIG. 1). The spherical portion 7 is connected to a plunger valve (not shown), and when the brake pedal is depressed, the spherical portion 7 swings like a universal joint within the plunger valve, which is connected to the operating rod and the plunger valve. The sphericity of the spherical portion 7 is important. However, the method of manufacturing the operating rod 1 involves turning a material whose overall outer diameter is the outer diameter of the collar portion 5, or upsetting and forging the collar portion 5 from a material with the thickness of the shaft portion 4, and then Spherical part 7 and thin shaft part 6 at the tip
The yield rate from material weight to product weight is 60-70% for the former and 80-70% for the latter.
85%, and it is particularly difficult to turn the spherical part 7, and the shape of the spherical part 7 cannot be maintained constant, resulting in variations in length over the whole, and the turning roughness peculiar to turning remains as streaks. When it is necessary to remove the striations by cloth polishing, and the striations remain on the spherical part 7 at the tip and this part abuts inside the plunger valve, it is generally made of harder steel than the plunger valve. It also has drawbacks in terms of its manufacture and use, such as excessive friction caused by the operating rod 1, which causes wear inside the plunger valve. Therefore, the present invention aims to eliminate the above-mentioned drawbacks, improve product quality and manufacturing efficiency, and reduce manufacturing costs.

The present invention will be described in detail with reference to FIGS. 1 to 8. A raw material A is obtained by cutting a straight round bar having the same thickness as the shaft portion 4 into a certain length. Next, the material A is inserted into the die 10 having a blank insertion hole 11, a squeeze hole 12, and an escape hole 13, and pushed in with a push pin 14 (see Fig. 3).
4) and the material A pass through the ironing hole 12, are pressed into the shaft part 18, are pushed out into the relief hole 13, come into contact with the ejector pin 15, finish the processing of the thin shaft 18, and are pushed into the push pin. 14 retreats (rightward in FIGS. 3 and 4), and the ejector pin 15 moves forward to push out the material B and release it. The corner portion 16 at the upsetting entrance of the ironing hole 12 is
Since this is the minimum radius of curvature suitable for upsetting, the corner portion 17 of the material B is also processed to have the minimum radius of curvature. In this primary processing, the push pins 14 and ejector pins 15 may be operated mechanically, but pneumatic or hydraulic pressure is more advantageous in terms of noise and pressing force, and this manufacturing equipment uses hydraulic pressure (lower In the same way, we will discuss the case where hydraulic pressure is used for pressurization in processing).

The material B that has undergone the primary processing has a left die 22 (left side in FIG. 5) consisting of a hole 24 corresponding to the shaft portion 19, a squeeze hole 25, and an escape hole 26, a collar portion 20, and a thin shaft. The ejecting pin 27 and push pin 29 are inserted into each of the right die 23 (on the right side in FIG. 5) having a hole 28 in which the portion 18 is formed, and the left die 2
2 and the right die 23 are both opened, insert the shaft part 19 of the material B into the hole 24 of the left die 22, and when the right die 23 approaches and the thin shaft part 18 starts to be inserted into the hole 28, the fine shaft Since the material B is pushed into the left die 22 by the corner part 17 of the shaft part 19 which is thicker than the part 18, the shaft part 19 is pushed to the left by the squeeze hole 25, and the ejecting pin 27 is chamfered as shown in FIG. 3
The push pin 29 moves forward (the fifth
(leftward in the figure) and presses the end of the thin shaft portion 18, so the thin shaft 21 is forcibly passed through the ironing hole 25 on the left die 22 side and ironed to the effective diameter of the threaded portion 2, which will be described later, and escapes. A chamfered portion 30 is formed at the end of the thin shaft 21 in contact with a tapered portion 31 formed at the end of the hole 26 . On the other hand, the right die 23 makes contact with the left die 22 to bulge the collar 20, and the left die 2
2. The holes 24 and 28 formed by the right die 23 are filled, and the molding of the material C is completed. Then, when the right die 23 retreats and becomes open, the ejector pins 27 and push pins 29 move forward to open the holes 24 and 2.
The material C remaining in 8 is released. In this secondary processing, the respective corner portions a, b, c, and d of the left die 22 and right die 23 are formed into the aforementioned corner portions 16.
Similarly, since it is configured with the minimum radius of curvature that is necessary for forming the part, protects the mold, and does not cause damage to the product, the stress of the completed operating rod 1 as a shaft is reduced. It is possible to form and provide corners that can avoid damage due to concentration.

The forward extrusion processing method was used in the primary processing and the secondary processing, respectively, by means of the front and rear extrusion upsetting processing method using the left die 22 and right die 23, which are the same as in the secondary processing. , it is also possible to perform primary processing and secondary processing at the same time,
In this case, an excessive load is applied to the shaft portion 19, and the shaft portion 19 is
9 may cause buckling, strain on the ejector pin 27 or push pin 29 may result in breakage, or cracks may occur especially on the outer periphery of the collar portion 20 to be bulged. This is to avoid processing.

Furthermore, to describe the tertiary processing of processing material C into material E in Figs. 6 and 7, the shaft portion 1
9. It consists of an upper mold 32 and a lower mold 33 having a groove that can hold the collar part 20 and the thin shaft part 18, and the end of the fine shaft part 18 of the groove (on the right side in Fig. 6) has a hemispherical shape. The groove 34 is bored, the upper die 32 moves upward, and the material C is inserted in an open state with the lower die 33. The upper die 32 comes into contact with the lower die 33, grips the material C, and presses the tip of the preliminary punch 35. The formed groove 36 is preformed into a roughly egg-shaped spherical part 37 by strongly pressing or hitting the tip of the thin shaft part 18, and after separating the preliminary punch 35, the upper mold 32 is moved upward to take out the material D. . The material D is gripped and held in the same manner as the upper die 32 and the lower die 33 described above using the same means as used for processing the material D, and the spherical portion 37 is strongly pressed with the hemispherical groove 39 at the tip of the finishing punch 38. Alternatively, the spherical portion 40 is finished by strong hitting. The material D was previously taken out after preforming, but after being preformed with the preliminary punch 35, the material D may be finished formed while being held by the upper die 32 and the lower die 33 with the finishing punch 38. There is no problem. The thus obtained spherical part 4
0 is because the upper die 32 and the lower die 33 are composed of two split dies, and the finished spherical part 40 is slightly damaged by the upper die 32 and lower die 33 portions that contact the preliminary punch 35 and the finishing punch 38, respectively. Since the protruding burr-like streaks that become excess thickness appear as protrusions, as shown in FIG. 44, and the rolls 41 and 42 clamp and rotate the spherical part 40 to crush and remove the sphericity of the spherical part 40 as well as the protruding excess flesh.

The material D obtained in the above manner is processed by rolling the threaded part 2 and the knurled part 3 in the conventional manner, and is further plated as necessary to form the threaded part 2, knurled part 3, and shaft, respectively. An operating rod 1 is manufactured in which the portion 4, the collar portion 5, the thin shaft portion 6, and the spherical portion 7 are integrated.

Further, although explanations are omitted during each step, bonderite treatment may be performed between each step as necessary to promote workability. In addition, all of this processing is performed by cold processing, but warm processing can also be used to accelerate processing, but in the case of warm processing, manufacturing costs are generally high, and the process occurs when the material is heated. This is undesirable because the peeling of the black skin causes the surface to become rough and the product value is reduced, which is contrary to the spirit of the present invention.

By forming the operating rod using the manufacturing apparatus and manufacturing method of the present invention, unlike the conventional example where a round bar is finished by cutting or a part is forged or upset and then finished by cutting. , because we perform cold upsetting up to the entire forming process,
Does not require a press with large capacity like forging,
Noise can be reduced, most can be automated, and materials can be
A yield improvement of close to 100% can be expected. Moreover,
The brim gets thicker around the shaft, the thinner shaft gets thinner,
The corner part that continues from the thin shaft part to the spherical part is connected with a uniform radius of curvature, which avoids stress concentration, and also contributes to improving the material quality of the product, which is a characteristic of cold working, and significantly improves the overall quality of the product. It also improves strength, and even if the whole part is made thinner, it can be made even thinner than by cutting out the whole part, so material costs and manufacturing costs can be lowered, and the product can be made lighter. Moreover, Shigoki
Surface hardening by upsetting is promoted, and the surface is hard and smooth, so even when plating, for example, there is no need for cloth polishing as in conventional methods, and the surface finish is beautiful, and the surface is as described above. Since hardening is more accelerated in lower carbon steels, the reduction in material costs and manufacturing costs is doubled along with the reduction in processing time. Furthermore, since the spherical part in particular becomes smooth, there is no risk of wear on the inside of the plunger valve that comes in contact with the part, and the spherical part can be formed into a more accurate spherical shape than by turning. This has many effects, such as improving the length accuracy of the rod.

[Brief explanation of the drawing]

Fig. 1 is an overall side view of the operating rod according to the present invention, and Fig. 2 is a side view of the material in each manufacturing process. Material B that has undergone primary processing, C represents material C that has undergone secondary processing, D represents material D in tertiary processing, and E represents material E at the end of tertiary processing. Figure 3 is a cross-sectional view of the material A in the die before primary processing, Figure 4 is a cross-sectional view of the state after primary processing, and similarly Figure 5 is a cross-sectional view of the material A in the die before primary processing. FIG. 6 is a cross-sectional view showing the state of the spherical part in the pre-beating state, FIG. 7 is a cross-sectional view showing the state of the spherical part in FIG. FIG. 8 is a top view showing the state in which the spherical part is rolled.

Claims (1)

[Claims] 1. In an operating rod 1 consisting of a threaded portion 2, a knurled portion 3, a shaft portion 4, a collar portion 5, a thin shaft portion 6, and a spherical portion 7, a long round bar is made into a certain length. Material A is obtained by cutting, and the thin shaft part 18 is produced in the first processing.
The material B in which the shaft portion 19 has been formed and the corner portion 17 has been formed is subjected to secondary processing to form the thin shaft portion 18, the shaft portion 19, the collar portion 20, and the thin shaft 21, and is chamfered 3.
After obtaining the material C by zeroing, the spherical part 40 is formed into a spherical shape by pre-striking and finishing-stamping the tip of the thin shaft part 18 in the tertiary processing, and then the spherical part 40 is formed into a spherical shape by the sandwiching rotation of the rolls 41 and 42. A method of manufacturing an operating rod for a brake booster, characterized in that a portion 40 is processed into a true spherical shape. 2 Cut a long round bar to a certain length to obtain material A. Pass this material into blank insertion hole 11, ironing hole 12,
A primary processing device consisting of an ejecting pin 15 that is inserted into a die 10 having an escape hole 13, pushed in with a push pin 14, and squeezed to extrude the material B into a thin shaft portion 18 and a shaft portion 19; 24・Shigoki hole 25・
A left die 22 consisting of an escape hole 26 and a collar portion 2
The ejecting pin 27 and push pin 29 are inserted into the right die 23 having a hole 28 in which a thin shaft portion 18 is formed. A secondary processing device capable of moving backward; a gripping means consisting of an upper mold 32 and a lower mold 33 having grooves capable of holding the shaft portion 19, the collar portion 20, and the thin shaft portion 18; A hemispherical groove 34 is bored at the end of the shaft portion 18, and a groove 36 is bored at the tip of the preliminary punch 35 or a hemispherical groove 39 is bored at the tip of the finishing punch 38 opposite to the groove 34 to form the preliminary punch. A manufacturing device for an operating rod for a brake booster, which is equipped with a tertiary processing device comprising a finishing punch forming means, and is configured to obtain a material E from a material A.