JP2002035886A - Forming method of shaft and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce punching processes necessary for forming a shaft having a cup section and the number of parts as many as possible and achieve reduction of production cost. SOLUTION: The forming device 10 is provided with a fixed part 12 and a movable part 14. The movable part 14 is provided with an insert punch 68 and a piston 82 located in a first holder 72. The piston 82 is slidable on the outer peripheral face of the third shaft 68c of insert punch 68. A chamber 85 formed by the first holder 72 and the piston 82 is filled with oil 108. A sleeve punch 90 which is slidable on the outer peripheral face of a fourth shaft 68d of the insert punch 68 is fixed to a support member 88 fitted to a recess 86 of the piston 82, that is, the insert punch 68 is inserted slidably in the sleeve punch 90.

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 Generally, a shaft connecting left and right drive shafts of a front-wheel drive motor vehicle has a cup portion (tubular portion) having a straight tooth profile. This shaft is formed through first to third punching steps.

Specifically, first, a long cylindrical work is formed into a shaft 1 having a predetermined outer shape by a first punching process (see FIG. 5A). Next, the cup part 2 is formed at one end of the shaft 1 by a second punching process (see FIG. 5B). Next, a straight tooth profile 3 is formed in the cup 2 (see FIG. 5C). In this case, three forming apparatuses corresponding to the respective punching processes are used. Further, between each punching step, for example, an intermediate treatment such as a heat treatment for removing residual stress or a lubricating film treatment on the surface of the shaft 1 is performed. Finally, a tooth profile is formed on the other end of the shaft 1 by machining to complete the product.

[0004]

However, in the above-mentioned conventional molding method, since a molding device corresponding to each punching step is used, for example, a shaft such as a mold provided in each molding device is formed. In addition, the number of parts required for the method is significantly increased, and a plurality of punching steps are required.
Further, it is pointed out that an intermediate process is performed between the respective punching steps, so that the cost increases, and the manufacturing cost also increases.

The present invention has been made in view of such problems, and a punching process is reduced as much as possible to form a shaft having a cup portion, and at the same time a tooth profile portion is formed in the cup portion. In addition, the number of molding devices and the number of parts required to mold a shaft having a cup portion can be reduced as much as possible, and the number of intermediate processes performed during the punching process can be reduced. It is an object of the present invention to provide a shaft molding method and a shaft molding method capable of achieving a reduction in manufacturing cost by enabling reduction as much as possible.

[0006]

According to the present invention, a workpiece is housed in a cavity formed in a mold, and an annular first punch and a second punch slidably inserted into the first punch. A first step of pressing the workpiece with the punch, and a pressure applied to a piston connected to the first punch is reduced by the action of a pressing mechanism to reduce the pressure of the second punch. A second step of projecting from the inside of the first punch and further pressing the work by the second punch to form a cup (cylindrical part) on the work.

In the above-described method of forming a shaft, a tooth forming portion is formed at a tip portion of the second punch, and when the work is further pressed by the second punch, a cup portion is formed on the work. Preferably, a tooth profile is formed on the inner peripheral surface of the cup at the same time as the molding.

The present invention also provides an annular first punch,
A second punch inserted into the first punch, wherein the first punch is connected to a piston and changes a pressing force applied to the piston under the action of a pressing mechanism. Thereby, the second punch slides in the first punch. In this case, it is preferable that a tooth forming portion is formed at the tip of the second punch.

According to the present invention, when a work is pressed by the first punch and the second punch, the work is formed into a shaft having a predetermined outer shape. Thereafter, the work is further pressed by the second punch, so that a cup portion (cylindrical portion) can be formed on the work.
Thereby, the shaft having the cup portion can be molded by one molding device, so that the punching process can be reduced as much as possible, and the number of molding devices necessary for molding the shaft is reduced as much as possible. In addition to reducing the number of parts, the number of parts constituting the molding apparatus, such as dies, can be reduced as much as possible. Therefore, when a plurality of punching steps are performed, the number of intermediate processes performed between each punching step can be reduced, and the manufacturing cost can be reduced.

Further, by forming the tooth forming part at the tip of the second punch, it is possible to form the cup part on the work and simultaneously form the tooth part on the inner peripheral surface of the cup part. As a result, the number of punching steps can be further reduced, and the manufacturing cost can be further reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a shaft forming method according to the present invention in relation to a forming apparatus for carrying out the method will be described below with reference to FIGS. explain. Although the use of this molding method is not limited, it is preferably used, for example, for molding a shaft connecting left and right drive shafts of a front-wheel drive automobile.

A molding apparatus 10 according to the present embodiment has a structure shown in FIG.
As shown in FIG. The fixed part 12 has a first gantry 16 and a second gantry 18 fixed on the first gantry 16, and a small-diameter part 20 and a large-diameter The hole 24 comprising the part 22
Is formed, and the opening 2 communicating with the hole 24 is formed.
6 is formed at a substantially central portion of the second gantry 18. A guide 28 is fixed to the large-diameter portion 22, and a knock-out punch 30 is inserted into the small-diameter portion 20 and the large-diameter portion 22, that is, the hole 24 so as to slidably pass through a substantially central portion of the guide 28. Is inserted. This knockout punch 30
Is a control mechanism (not shown) located below in FIG.
It is connected to. Therefore, the knockout punch 3
Numeral 0 is vertically movable under the action of the control mechanism. The upper flat surface 32 of the second gantry 18 is provided with a plurality of bolt holes 34 spaced apart from the axis of the second gantry 18 by a predetermined angle.

The opening 2 formed in the second base 18
6, a claw 3 provided integrally with the second base 18;
An annular first mold 38 that engages with 6 is fitted. An annular second mold 40 is engaged with the first mold 38, and a third mold 42 is fitted on the second mold 40. further,
A fourth mold 44 having a claw portion 44a formed thereon is engaged with the third mold 42. The first to fourth molds 38, 4
The thickness of each of the first, second, and fourth molds 0, 42, and 44 is such that the third mold 42 is the thickest, then the second mold 40 is the thickest, and the first mold has substantially the same thickness. 38 and the fourth mold 44 are formed to be the thinnest among the four molds.

The claw portion 44a of the fourth mold 44 is engaged with a claw portion 46a of a tightening ring 46. Then, a plurality of tightening bolts 47 pass through the tightening ring 46 and are screwed into the bolt holes 34 formed in the upper flat surface 32 of the second gantry 18. As a result, the first mold 38, the second
Mold 40, the third mold 42, and the fourth mold 4
4 are integrally tightened.

The first to fourth dies 38, 40, 42,
44, the first to fourth molds 3
A cavity 48 communicating with 8, 40, 42, 44 is formed. The cavity 48 has a first linear portion 50.
A first tapered portion 52 inclined at a predetermined angle in a direction away from the axis from the first linear portion 50; and a second linear portion 54 extending in the axial direction from the first tapered portion 52 A second tapered portion 56 inclined by a predetermined angle in a direction away from the axis from the second linear portion 54, and a third straight line extending in the axial direction from the second tapered portion 56 And a unit 58.

The movable section 14 includes a third mount 60 and the third mount 60.
And a fourth frame 64 fixed to the bottom surface 62 of the frame 60. A hole 66 is formed at a substantially central portion of the fourth frame 64. The hole 66 has a substantially cylindrical first diameter whose diameter decreases in four steps as it goes downward in FIG.
Insert punch 68 having fourth to fourth shaft portions 68a to 68d is mounted. The third gantry 60 is connected to a driving mechanism (not shown) in the upper part of FIG. Therefore, under the action of the drive mechanism, the third gantry 60, that is, the insert punch 68, can move up and down in the vertical direction.

A first holder 72 is fixed to the bottom surface 70 of the fourth gantry 64. The first holder 72 has a substantially U-shape, and the insert punch 6
8 penetrates. That is, the side wall portion 72b of the first holder 72 extends downward in FIG. 1 and is substantially parallel to the insert punch 68. Also,
An annular bulging groove 74 is formed on a side of the bottom portion 72a that is not fixed to the fourth gantry 64, and a cutout groove 76 is formed on an outer peripheral surface of the side wall portion 72b. The groove 74 communicates with the notch groove 76 through a first communication port 78.

In the first holder 72, a piston 82 surrounding a third shaft portion 68c of the insert punch 68 via a plurality of O-rings 80 is provided. A plurality of piston rings 84 are interposed between the piston 82 and the inner peripheral surface of the side wall 72b of the first holder 72. Therefore, the piston 82 is connected to the third shaft 68c.
Is slidable between the outer peripheral surface of the base member and the inner peripheral surface of the side wall portion 72b, and a chamber 85 is formed by the bottom portion 72a, the side wall portion 72b, and the piston 82.

An annular recess 86 is formed on the side of the piston 82 not facing the bottom 72a.
6 is fitted with an annular support member 88 surrounding the fourth shaft portion 68d of the insert punch 68. A substantially central portion of the support member 88 is provided with a third
A concave portion 89 slightly larger in diameter than the diameter of the shaft portion 68c is formed. Further, a sleeve punch 90 slidable on the outer peripheral surface of the fourth shaft portion 68d is fixed to one end surface 91 of the support member 88. In other words, the insert punch 68 is slidably inserted into the sleeve punch 90. A claw portion 92a of a holding member 92 fixed to one end surface 91 of the support member 88 is engaged with a claw portion 90a formed on the sleeve punch 90.

A step 94 is formed at the end of the inner peripheral surface of the side wall 72b of the first holder 72, and a ring 96 is fixed to the step 94. This ring 96 is an O-ring 98
Through the support member 88.

The first holder 72 is provided with a second holder 100. In the second holder 100, a second communication port 102 communicating with a first communication port 78 formed in the first holder 72 is formed, and the second communication port 102 is provided with the second communication port 102. A connection portion 104 for connecting the second holder 100 and a pressing mechanism (not shown) is provided. Therefore, the chamber 85 formed by the first holder 72 and the piston 82, the first communication port 78, the notch groove 7
The sixth communication port 102 and the second communication port 102 are connected to the pressure mechanism (not shown) via a connection portion 104.

The lower end surfaces of the first holder 72, the ring 96 and the second holder 100 in FIG. 1 are flush with each other, and an annular plate 106 is fixed so as to include the respective lower end surfaces.

The molding apparatus 10 according to the present embodiment is basically configured as described above. Next, the operation and effects of the apparatus will be described in relation to the molding method.

First, as shown in FIG. 1, under the driving action of a driving mechanism (not shown), the movable part 14 is separated from the fixed part 12, and the first to fourth dies 38, 40, 4
A substantially columnar work W is accommodated in a cavity 48 formed in each of the bases 2 and 44. At this time, under the action of the pressurizing mechanism (not shown), the control valve (not shown) interposed between the pressurizing mechanism and the connecting portion 104 is opened to supply the oil 108 into the chamber 85. Fill. It is preferable to use hydraulic pressure for the pressurizing mechanism. In this case, the oil 108 flows into the chamber 85 through the second communication port 102, the notch groove 76, and the first communication port 78. Then, the fourth shaft portion 68d of the insert punch 68
While pressing the piston 82 with oil 108 until the end face of the sleeve punch 90 is flush with the end face of the sleeve punch 90, the chamber 8
5 is filled with oil 108 (see FIG. 1).

Next, the driving mechanism is driven to move the movable section 14 vertically downward to bring the movable section 14 closer to the fixed section 12 (see FIG. 2). Thus, the work W accommodated in the cavity 48 is pressed by the insert punch 68 and the sleeve punch 90. In this case, the piston 82 is always pressed by the oil 108 such that the end face of the insert punch 68 and the end face of the sleeve punch 90 are flush. Thereby, the work W is formed into a shaft having a predetermined outer shape.

Next, under the action of the pressurizing mechanism, the pressing force for pressing the piston 82 is reduced. At the same time, the driving mechanism is driven. As a result, the insert punch 68 protrudes from the inside of the sleeve punch 90, and the work W is further pressed. In this case, the piston 82 slides vertically upward on the outer peripheral surface of the third shaft portion 68c of the insert punch 68, and the third shaft portion 68c is inserted into the recess 89 formed in the support member 88. Portion is accommodated (see FIG. 3). Thereby, the cup WC is formed on the work W (see FIG. 3).

Thereafter, the driving mechanism is driven to move the movable portion 14.
Is moved away from the fixing portion 12, and the knockout punch 30 is moved vertically upward under the action of a control mechanism (not shown) (see FIG. 4). As a result, the work W is
8 and the work W is transferred to a transfer device (not shown).
Is transferred to the next step, and the cup WC of the work W
A tooth profile is formed by machining on the side where is not formed, and is finally processed to a predetermined size and shape to complete the product.

In this embodiment, a tooth forming portion for forming a straight tooth portion may be provided at the tip of the insert punch 68. Thereby, at the same time as forming the cup portion WC of the work W, the cup portion WC
It is possible to form a straight tooth profile portion on the inner peripheral surface of the shaft.

[0029]

As described above, according to the present invention,
When the work is pressed by the sleeve punch and the insert punch, the work is formed into a shaft having a predetermined outer shape. Thereafter, the work is further pressed by the insert punch, so that a cup portion (cylindrical portion) can be formed on the work. Thereby, the shaft having the cup portion can be molded by one molding device, so that the punching process can be reduced as much as possible, and the number of molding devices necessary for molding the shaft is reduced as much as possible. In addition to reducing the number of parts, the number of parts constituting the molding apparatus, such as dies, can be reduced as much as possible.
Therefore, when a plurality of punching steps are performed, the number of intermediate processes performed between each punching step can be reduced, and the manufacturing cost can be reduced.

Further, by forming the tooth forming part at the tip of the insert punch, it is possible to form the cup part on the work and simultaneously form the tooth part on the inner peripheral surface of the cup part. As a result, it is possible to further reduce the number of punching steps, and to achieve a unique effect that a further reduction in manufacturing cost can be achieved.

[Brief description of the drawings]

FIG. 1 is a partially omitted vertical cross-sectional explanatory view showing a molding apparatus according to the present embodiment.

FIG. 2 is a partially omitted longitudinal cross-sectional view showing a state in which a work is pressed by an inner punch and a sleeve punch in the molding apparatus of FIG. 1;

FIG. 3 is a partially omitted longitudinal sectional view showing a state in which the work shown in FIG. 2 is further pressed by an inner punch.

FIG. 4 is a partially omitted vertical cross-sectional explanatory view showing a state in which a movable section is separated from a fixed section in the molding apparatus of FIG. 1;

5A is an explanatory front view showing a shaft formed by a first punching step of a forming method according to the related art, and FIG. 5B is a diagram showing a cup formed on the shaft of FIG. 5A by a second punching step. FIG. 5C is a partially cutaway front view showing the state in which the pressing is performed, and FIG.
FIG. 5 is a partially exploded front view showing a state in which a tooth profile is formed in the cup portion of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Molding apparatus 38 ... 1st metal mold 40 ... 2nd metal mold 42 ... 3rd metal mold 44 ... 4th metal mold 48 ... Cavity 68 ... Insert punch 82 ... Piston 90 ... Sleeve punch W ... Work WC … Cup part

Continued on the front page (72) Inventor Ryuji Sawamura 8-1 Honcho, Wako-shi, Saitama Honda Motor Co., Ltd. Wako Factory, Saitama Seisakusho (72) Inventor Katsuhiro Sekine 8-1 Honcho, Wako-shi, Saitama Honda Motor Co., Ltd. F-term in the Wako Factory of Saitama Manufacturing Co., Ltd. (reference) 4E087 AA10 BA17 CA25 CB01 CB03 EC19 HA08 HA38

Claims (4)

[Claims] 1. A work is accommodated in a cavity formed in a mold, and the work is pressed by an annular first punch and a second punch slidably inserted into the first punch. A first step of reducing the pressing force applied to a piston connected to the first punch under the action of a pressing mechanism to cause the second punch to protrude from the inside of the first punch. A second step of further pressing the work with the second punch to form a cup (cylindrical part) on the work. 2. The method of forming a shaft according to claim 1, wherein a tooth forming portion is formed at a tip end of the second punch, and when the work is further pressed by the second punch, A method for forming a shaft, comprising: forming a cup portion on a work; and forming a tooth profile portion on an inner peripheral surface of the cup portion at the same time. 3. A first punch having an annular shape, and a second punch inserted into the first punch, wherein the first punch is connected to a piston and functions as a pressing mechanism. A shaft forming apparatus, wherein the second punch slides in the first punch by changing a pressing force applied to the piston below. 4. The shaft forming apparatus according to claim 3, wherein a tooth forming part is formed at a tip end of the second punch.