JP2003211253A - Forming method of shaft and its device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce as much as possible a forging forming process and a number of components necessary for the forming of a shaft having a large diameter part and a projecting part which extends from the large diameter part, and to reduce a manufacturing cost. <P>SOLUTION: A forming device 10 has a fixing part 12 and a movable part 14. The sleeve punch 70 is fitted in a hole part 68 of a sleeve punch holder 60 which forms the movable part 14. An inner punch 74 which is vertically movable freely in a hole part 72 under an action of a piston 78 is inserted in the hole part 72 of the sleeve punch 70. Firstly, a work W inserted in a cavity 44 is pressed by the sleeve punch 70 and the inner punch 74, and a tapered shape stage parts 3a and 3b and a large diameter part 4 are installed. Then, while pressing only by sleeve punch 70 is continued, the inner punch 74 is raised. By a plastic flow of a metal of the work W to be built up following to the raised inner punch 74, a projecting part 5 which is extended from the large diameter part 4 is formed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft forming method and apparatus for forming a shaft by hot forging or cold forging.

[0002]

2. Description of the Related Art As shown in FIG. 6, a counter shaft 1 incorporated in a transmission of an automobile generally has a shaft portion 2 and a tapered step portion 3 provided on the shaft portion 2.
a, 3b and the large diameter portion 4 provided on the one end side of the shaft portion 2
And a protrusion 5 extending from the large diameter portion 4. Of these, a toothed portion 6 that meshes with a gear of an input shaft that constitutes the transmission is formed on a side peripheral wall portion of the large diameter portion 4.

The counter shaft 1 is manufactured as follows. That is, first, in the first forging forming step, by pressing the work W, which is a long cylindrical body (see FIG. 7A), from the upper end side, along the longitudinal direction of the work W as shown in FIG. 7B. Taper step 3
a and 3b are provided. Hereinafter, this is referred to as draw forming.

Next, in the second forging forming step, the upper end of the work W is crushed by performing upsetting, and a large diameter portion 4 is provided as shown in FIG. 7C.

Next, in the third forging forming step, backward extrusion forming is performed in which the work W is pushed up from the lower end side while the peripheral portion of the large diameter portion 4 is being pressed, as shown in FIG. 7D.
As shown in FIG. 3, a protruding portion 5 protruding from the large diameter portion 4 is provided.

Finally, the toothed portion 6 is formed on the side peripheral wall portion of the large-diameter portion 4 by machining or forging, and the counter shaft 1 (see FIG. 6) is obtained.

[0007]

By the way, in the above-mentioned first to third forging forming steps, three forging forming apparatuses corresponding to the respective forging forming steps, that is, a draw forming apparatus, an upsetting apparatus and a rear forming apparatus. Extrusion equipment is used. For this reason, for example, the number of parts required to manufacture the counter shaft 1 such as a die provided in each forging forming apparatus as well as the forging forming apparatus becomes enormous. In addition, since it is necessary to perform the forging step a plurality of times, there is a problem that the manufacturing step becomes complicated.

Further, during each forging process,
It is necessary to perform an intermediate treatment such as a heat treatment for the purpose of removing residual stress and a lubricating coating treatment for providing a lubricating coating on the surface of the molded product so that the forging molding can proceed smoothly. For this reason, it has been pointed out that the cost of manufacturing the counter shaft 1 by forging increases, which in turn increases the manufacturing cost.

The present invention has been made in order to solve the above-mentioned problems, and makes it possible to mold a shaft having a large diameter portion and a protruding portion, thereby reducing the forging step as much as possible. It is an object of the present invention to provide a shaft molding method and a shaft molding method that are capable of achieving a reduction in manufacturing cost.

[0010]

In order to achieve the above-mentioned object, according to the present invention, a cavity formed in a mold accommodates a work made of an elongated body, and a first punch and the first punch are provided. An upsetting step of providing a large diameter portion on the work by pressing the work with a second punch slidably inserted therein, and pressing the peripheral portion of the large diameter portion with the first punch At the same time, the pressing force applied to the piston connected to the second punch is reduced to retract the second punch into the first punch so that the protruding portion extending from the large diameter portion is removed. And an extruding step to be provided.

According to this forming method, each forging forming step is continuously performed without performing an intermediate treatment on the work. For this reason, the forging process can be reduced as much as possible, so that the manufacturing process can be prevented from becoming complicated. Moreover, since the intermediate treatment is unnecessary, the manufacturing cost of the shaft can be reduced.

In the upsetting process, it is possible to provide a step on the shaft of the work. Therefore, forging can be continuously performed even when manufacturing a shaft having a step.

As a preferable example of the shaft manufactured by such a molding method, shafts constituting an automobile transmission, particularly a counter shaft can be mentioned.

Further, according to the present invention, a fixed portion, a die provided in the fixed portion, a cavity provided in the die, a movable portion that can be moved toward and away from the fixed portion, and a movable portion are provided in the movable portion. A first punch that is positioned and fixed; a second punch that is slidably inserted into the first punch; and a piston that is connected to the second punch, and is housed in the cavity A large-diameter portion is formed on the work by pressing the work made of the elongated body with the first punch and the second punch, and then the pressing by the first punch is continued, and the piston By depressing the pressing force applied to the second punch, the second punch is relatively retracted in the first punch, and the meat of the large diameter portion of the workpiece is plastically fluidized in accordance with the retracting operation. Projection on the large diameter part It is characterized by forming a part.

With such a structure, the work can be provided with the large diameter portion and the protruding portion by one forging machine. Therefore, the number of forging devices and the number of parts required for forming the shaft can be reduced as much as possible, so that the manufacturing equipment can be significantly simplified. Inevitably, the manufacturing cost will be significantly reduced.

When molding a shaft having a stepped portion, the cavity may be provided with a large diameter portion and a small diameter portion. A taper portion may be provided between the large diameter portion and the small diameter portion to facilitate plastic flow.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the method of molding a shaft according to the present invention will be described below in detail with reference to the accompanying drawings, in connection with preferred embodiments. In the present embodiment, the case where the counter shaft 1 (see FIG. 6) that constitutes a transmission of an automobile is manufactured is illustrated as the shaft.

FIG. 1 shows a counter shaft molding apparatus according to the present embodiment (hereinafter sometimes simply referred to as a molding apparatus). The molding apparatus 10 has a fixed portion 12 and a movable portion 14.

In the fixed portion 12, the hard plate 1
The first to third dice 18, 20, 22 are laminated on the 6 in this order. Of these, the first die 18 and the third
Tightening rings 24 and 26 are fitted onto the die 22, respectively, and bolt holes 28 and 30 are provided in the fastening rings 24 and 26. When the bolt 32 that has passed through the bolt hole 28 is screwed into the bolt hole 30,
~ The third dies 18, 20, 22 are integrally clamped and held.

The tightening rings 24 and 26 are supported from the outer peripheral side by support members 34 and 36. That is, the lower end of the tightening ring 24 is sandwiched by the supporting members 34, while the tightening ring 26 is sandwiched by the supporting members 36 connected to the upper end side of the supporting members 34.

The foot portion 34a of the support member 34 is connected to an exterior member 38 arranged outside the hard plate 16 by a bolt (not shown). Further, the exterior member 38 and the hard plate 16 are positioned and fixed on a frame 39.

Here, the mount 39 and the hard plate 1
6, through holes 40 and 41 are provided, and knockout pins 42 are inserted into these through holes 40 and 41. The knockout pin 42 is connected to a control mechanism (not shown), and is vertically movable under the action of the control mechanism.

The first to third dice 18, 20, 22 are
A cavity 44 communicating with the through hole 40 is provided. The cavity 44 includes a first straight line portion 46 and a first taper portion 48 that is inclined at a predetermined angle in a direction away from the first straight line portion 46 with respect to the longitudinal direction from the lower side in FIG. 1.
A second linear portion 50 extending in the longitudinal direction from the first tapered portion 48, a second taper portion 52 inclined by a predetermined angle in a direction away from the second linear portion 50 in the longitudinal direction, Third straight line portion 5 extending in the longitudinal direction from the second taper portion 52.
4 and a fourth straight line portion 56 having a larger diameter than the third straight line portion 54.
It consists of and. In addition, the first taper portion 48, the second
The taper portion 52 and the fourth straight portion 56 are provided on the first die 18, the second die 20, and the third die 22, respectively.

On the other hand, the movable portion 14 has a sleeve punch holder 60, a piston pin guide 62 fixed to the bottom surface of the sleeve punch holder 60, and a counter punch holder 64, of which the counter punch holder 64 is included.
Are held in the cylinder case 66. A sleeve punch 70 (first punch) is fitted in the hole 68 provided in the sleeve punch holder 60.

The sleeve punch 70, the piston pin guide 62 and the counter punch holder 64 are provided with a hole 72, and an inner punch 74 (second punch) is inserted into the hole 72. . The lower end of the inner punch 74 in FIG. 1 is surrounded by the sleeve punch 70. When the inner punch 74 moves up and down,
The sleeve punch 70 is brought into sliding contact with the inner peripheral wall portion.

As is clear from FIG. 1, the cylinder case 66 is provided with a chamber 76.
A piston 78 including a small diameter portion 78a and a large diameter portion 78b is housed therein so as to be vertically movable. The upper end surface of the inner punch 74 is connected to the lower end surface of the small diameter portion 78a of the piston 78. Therefore, the inner punch 74 moves up and down as the piston 78 moves up and down. An annular groove is formed in the side peripheral wall portion of the large diameter portion 78b, and a piston ring 80 as a seal member is fitted in the annular groove.

A piston pin 82 is connected to the lower end surface of the large diameter portion 78b. The lower end portion of the piston pin 82 projects from the sleeve punch holder 60 through a guide hole 84 formed in the piston pin guide 62.

The cylinder case 66 is connected to a drive mechanism (not shown) in the upper part of FIG. That is, the cylinder case 66, and thus the movable portion 14, is vertically movable under the action of the drive mechanism.

The sleeve punch holder 60, the piston pin guide 62 and the counter punch holder 64 are
It is clamped by the support holder 85. A support holder pressing member 86 is also fitted on the sleeve punch holder 60, and the support holder 85 is sandwiched between the support holder pressing member 86 and the cylinder case 66. The large-diameter portion of the support holder 85 is connected to a case cover 87 fitted on the cylinder case 66.

The cylinder case 66 is provided with a small chamber 90 communicating with the chamber 76 via a notch groove 88, and the small chamber 90 is provided with a passage 92 formed in the case cover 87.
Is in communication with. A joint portion 94 of an oil supply / discharge mechanism (not shown) is connected to the opening of the passage 92. The oil supply / discharge mechanism is for supplying / discharging the hydraulic oil OL between the chamber 76 and the upper end surface of the large diameter portion 78b of the piston 78 as the piston 78 moves up and down.

The molding apparatus 10 according to this embodiment is basically constructed as described above. Next, its operation and effect will be explained in relation to its molding method.

First, as shown in FIG. 1, the movable portion 14 is separated from the fixed portion 12 under the driving action of a driving mechanism (not shown), and the first to third dies 18, 20 are formed. Two
The long cylindrical work W in the cavity 44 formed in
To house. At this point, the lower end of the work W is locked by the second taper portion 52 and protrudes from the cavity 44.

Then, the working oil OL is supplied from the oil supply / discharge mechanism to the chamber 76, and thereby the piston 78 is lowered to the bottom dead center. In this case, the hydraulic oil OL passes through the joint portion 94, the passage 92 and the small chamber 90 and flows into the chamber 76.
When the piston 78 reaches the bottom dead center, the lower end surface of the inner punch 74 is flush with the lower end surface of the sleeve punch 70.

Next, the driving mechanism is driven to move the movable portion 14 vertically downward to approach the fixed portion 12, as shown in FIG. As a result, the work W housed in the cavity 44 is pressed and compressed by the inner punch 74 and the sleeve punch 70. As a result, the shaft portion 2 of the work W is reduced in diameter to a shape corresponding to the shape of the cavity 44, and finally, at a position corresponding to the first taper portion 48 and the second taper portion 52 of the cavity 44 in the shaft portion 2. Form tapered steps 3a and 3b (drawing).

When the movable portion 14 is further moved vertically downward in this state, the upper end portion of the work W is crushed and the diameter thereof is expanded, as shown in FIG. That is, the large diameter portion 4 is formed on the work W (upsetting). At this time, the lower end surface of the piston pin 82 contacts the upper end surface of the third die 22.

In the above steps, the piston 78 is constantly pressed by the hydraulic oil OL, so that the lower end surfaces of the inner punch 74 and the sleeve punch 70 are kept flush with each other.

Then, the chamber 76 is operated under the action of the oil supply / discharge mechanism.
After the hydraulic oil OL is ready to be discharged, that is, the pressing force applied to the piston 78 is reduced, the movable part 14 is further moved vertically downward as shown in FIG.

At this time, when the sleeve punch 70 further presses the work W following the lowering operation of the movable portion 14, the piston 78 is pressed by the piston pin 82 which is in contact with the upper end surface of the third die 22. It Along with this, the hydraulic oil OL is discharged from the chamber 76,
The hydraulic pressure in the chamber 76 decreases. Therefore, the piston 7
8 is prevented by the piston pin 82 from descending following the movable portion 14, and eventually the piston 78 moves up relative to the descending movable portion 14. As a result, the inner punch 74 moves backward within the sleeve punch 70 while slidingly contacting the inner peripheral wall portion of the sleeve punch 70.

Therefore, the flesh on the upper end surface of the large diameter portion 4 which has been plastically flowed by being pressed by the sleeve punch 70 flows into a space between the inner punch 74 and the large diameter portion 4. As a result, a protrusion 5 having a diameter smaller than that of the large diameter portion 4 is formed on the upper end surface of the large diameter portion 4 so as to protrude. at the same time,
When the large diameter portion 4 is further expanded, the large diameter portion 4
Dimensional accuracy is improved.

As described above, according to the present embodiment, the draw forming is performed only by the forming device 10 without installing the draw forming device, the upsetting device and the rear extrusion device.
All upsetting and rear extrusion can be performed. That is, it is possible to reduce the number of forging and forming apparatuses and the number of parts.

Moreover, in this case, it is not necessary to take out the forged product each time one forging process is completed. Therefore, the manufacturing process is remarkably simple.

Further, for example, it is not necessary to provide a lubricating coating on the surface of the work W between the draw forming and the upsetting. Therefore, the manufacturing cost of the counter shaft 1 can be reduced.

After the above steps are completed, as shown in FIG. 5, the drive mechanism is driven to separate the movable portion 14 from the fixed portion 12, and the knockout pin is operated under the action of a control mechanism (not shown) not shown. 42 is moved vertically upward. As a result, the work W as a molded product is taken out from the cavity 44.

Finally, the work W taken out of the cavity 44 is conveyed to the next step by a conveying device (not shown), and the toothed portion 6 is formed on the large-diameter portion 4 by machining or forging. Counter shaft 1
Will be obtained.

Although the counter shaft 1 is illustrated as the shaft in the present embodiment, the shaft is not particularly limited to this, and a shaft having a large diameter portion and a protruding portion extending from the large diameter portion is used. I wish I had it. Further, it goes without saying that the shaft does not have to be the shaft that constitutes the automobile transmission.

[0046]

As described above, according to the present invention,
After the work is pressed by the first punch and the second punch to perform upsetting and a large diameter portion is provided, the work is further pressed by the first punch during the backward extrusion molding, while the second punch is pressed. By retracting the punch, a protrusion can be provided on the large diameter portion. That is, a shaft having a large diameter portion and a protruding portion can be molded with one shaft molding device.

Therefore, the number of forging devices or the number of parts required for forming the shaft and the forging process can be reduced as much as possible, so that the manufacturing process and equipment can be remarkably simplified. In addition, since intermediate treatments such as heat treatment and lubricating coating treatment can be reduced, the effect of significantly reducing the manufacturing cost can be achieved.

[Brief description of drawings]

FIG. 1 is an explanatory longitudinal sectional view of a main part of a shaft molding device according to an embodiment.

FIG. 2 is a longitudinal cross-sectional explanatory view of essential parts showing a state where a work is pressed by an inner punch and a sleeve punch in the molding apparatus of FIG.

FIG. 3 is a partially omitted vertical cross-sectional explanatory view showing a state where the work shown in FIG. 2 is further pressed by an inner punch and a sleeve punch.

FIG. 4 is a longitudinal cross-sectional explanatory view of essential parts showing a state where the work shown in FIG. 2 is further pressed only by the sleeve punch and the inner punch is retracted.

5 is a longitudinal cross-sectional explanatory view of an essential part showing a state where the movable part is separated from the fixed part in the molding apparatus of FIG.

FIG. 6 is an overall schematic front view of a counter shaft incorporated in a transmission of an automobile.

FIG. 7A is a schematic front view of a work, FIG. 7B is a schematic front view of a molded product formed by a first forging forming step of a forming method according to a conventional technique, and FIG. 7C is a second forging forming. It is a schematic front view of the molded product in which the large diameter part was formed by the process, and FIG. 7D is a schematic front view of the molded product in which the protrusion part was formed in the said large diameter part by the 3rd forge molding process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Counter shaft 2 ... Shaft part 3a, 3b ... Tapered step part 4 ... Large diameter part 5 ... Projection part 6 ... Tooth profile part 10 ... Molding device 12 ... Fixed part 14 ... Movable part 16 ... Hard plates 18, 20, 22 … Dice 42… Knockout pin 44… Cavities 46, 50, 5
4, 56 ... Straight portions 48, 52 ... Tapered portion 62 ... Piston pin guide 66 ... Cylinder case 70 ... Sleeve punch 74 ... Inner punch 76 ... Chamber 78 ... Piston 82 ... Piston pin 84 ... Guide hole 88 ... Notch groove 90 ... Small chamber 92 ... passage 94 ... joint OL ... hydraulic oil W ... work

Continued front page    (72) Inventor Ryuji Sawamura             8-1 Honmachi, Wako-shi, Saitama Honda Motor Co., Ltd.             Ceremony Company Saitama Factory Wako Factory (72) Inventor Katsuhiro Sekine             8-1 Honmachi, Wako-shi, Saitama Honda Motor Co., Ltd.             Ceremony Company Saitama Factory Wako Factory F-term (reference) 4E087 AA10 CA24 CA31 CB01 CB03                       CC01 DA05 EC19 HA31 HA38                       HA82 HB13

Claims (6)

[Claims] 1. A work formed of a long body is accommodated in a cavity formed in a mold, and the work is formed by a first punch and a second punch slidably inserted into the first punch. A step of providing a large-diameter portion on the work by pressing, and pressing the peripheral portion of the large-diameter portion with the first punch, and pressing the piston connected to the second punch. An extrusion step of providing a protrusion extending from the large diameter portion by reducing the pressure to retract the second punch into the first punch; and 2. The molding method according to claim 1, wherein a step is provided on the shaft of the work in the upsetting step. 3. A molding method according to claim 1 or 2, wherein shafts constituting a transmission of an automobile are manufactured. 4. The molding method according to claim 1, wherein a counter shaft is manufactured as the shafts. 5. A fixed part, a die provided in the fixed part, a cavity provided in the die, a movable part that can be moved toward and away from the fixed part, and positioning and fixed to the movable part. A long punch having a first punch, a second punch slidably inserted into the first punch, and a piston connected to the second punch; After a large-diameter portion is formed on the work by pressing the work made of a body with the first punch and the second punch, the pressing by the first punch is continued and is applied to the piston. The pressing force is reduced to cause the second punch to relatively move backward in the first punch, and the large diameter portion of the workpiece is plastically fluidized in accordance with the backward movement to cause the large diameter portion to move. To form a protrusion Shaft forming apparatus according to claim and. 6. The shaft molding apparatus according to claim 5, wherein the cavity has a large diameter portion and a small diameter portion.