JPH1133662A - Punch for forging multi-stage internally grooved member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate cracks with difficulty during the pressing by providing a first shaft part in which a first groove formed part is formed and a second shaft part in which a second groove formed part smaller in diameter than the first shaft part is formed on the inserting direction side through an inclined surface of the prescribed inclination relative to the axis, to form a multi-stage inner groove with high concentricity. SOLUTION: A punch for forging two-stage inner spline member comprises a first shaft part 2 and a second shaft part 4 which is continuous to the first shaft part through an inclined surface 3 of <=45 deg. relative to the axis on the inserting direction side, and smaller in diameter than the first shaft part 2. When the punch 1 is pressed into a columnar crude stock, a pinion for steering having the valve spline of large diameter formed by a first spline forming part 2a and the manual stopper spline of small diameter formed by a second spline formed part 4a, can be obtained in one process. The valve spline and the manual stopper spline can be formed with high concentricity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multistage internal groove member forging punch used for forging a multistage internal groove member, that is, a groove member having internal grooves such as two or more internal splines.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Application Laid-Open No. 62-40947 discloses a method for forging a spline member having a two-stage inner spline. In this forging method, first, a coarse material having a stepped hole composed of a large-diameter hole and a small-diameter hole is extruded from a cylindrical coarse material. Next, a large-diameter inner spline is formed by pressing the first punch into the large-diameter hole of the stepped hole of the coarse material. Then, the small diameter inner spline is formed by pushing the second punch into the small diameter hole of the stepped hole of the coarse spline member having the large diameter inner spline thus obtained. Thus, a spline member having a large-diameter inner spline and a small-diameter inner spline is obtained.

[0003]

However, in the above-described conventional forging method, the spline member is forged in two steps using two punches, a first punch having a large diameter and a second punch having a small diameter. It is difficult to secure coaxiality between the first punch and the second punch due to clearance for sliding the first and second punches, and it is difficult to form a large inner spline and a small inner spline with high coaxiality. There are drawbacks.

For this reason, as shown in FIG. 9, the present inventors have formed a first shaft portion 90 on which a first spline forming portion 90a is formed, and the first shaft portion 90 is continuous with the first shaft portion 90 on the insertion direction side. 1
The two-stage inner spline member forging punch 80 including the second shaft portion 91 having a smaller diameter than the shaft portion 90 and having the second spline forming portion 91a formed thereon was studied. The punch 80 is moved to the coarse material W.
10, the large-diameter valve spline S1 formed by the first spline forming portion 90a as shown in FIG.
And the steering pinion W having the small diameter manual stopper spline S2 formed by the second spline forming portion 91a can be obtained in one step, so that the valve spline S1 and the manual stopper spline S2 can be formed with high coaxiality. it can.

However, in the punch 80, as shown in FIG. 12A, it has been found that a crack C is easily generated at the end of the first shaft portion 90 on the side of the second shaft portion 91 at the time of pushing. This makes it impossible to accurately mass-produce the inner groove member. The present invention has been made in view of the above-mentioned conventional situation, and provides a multi-stage internal groove member forging punch capable of forming a multi-stage internal groove with high coaxiality and hardly causing cracks at the time of pushing. And

[0006]

[Means for Solving the Problems]

(1) As a result of intensive studies under the above-mentioned problem, the inventor has found that, when the punch 80 is pushed in, the first punch 80 is pushed.
The reason that the crack C is likely to occur at the end of the shaft 90 on the side of the second shaft 91 is that the first shaft 90 and the second shaft 91 are connected to each other via an orthogonal plane 92 orthogonal to the axis. It was discovered that this was the case, and completed the first invention.

That is, the punch for forging a multi-stage internal groove member according to claim 1 is a punch for forging a multi-stage internal groove member for forming a multi-stage internal groove member in a rough material in one step,
A first shaft portion having a first groove forming portion formed therein, the first shaft portion being continuous with the first shaft portion through an inclined surface of 45 ° or less with respect to the axis on the insertion direction side, and having a smaller diameter than the first shaft portion And a second shaft portion on which the second groove forming portion is formed.

When the punch according to claim 1 is pressed into the rough material, a multi-stage inner groove member having a large-diameter inner groove formed by the first groove forming portion and a small-diameter inner groove formed by the second groove forming portion is formed. Since it is obtained in one step, the multistage inner groove can be formed with high coaxiality. Further, when the punch of claim 1 is pressed into the coarse material, the material on the second shaft portion flows smoothly to the first shaft portion on the inclined surface, so that the stress concentration of the punch due to flow resistance is reduced. Cracks are less likely to occur at the second shaft side end of the first shaft.

The inclined surface according to the first aspect is 0 ° with respect to the axis.
And 45 ° or less. At 0 ° with respect to the axis, no inclined surface is formed, and the first shaft portion and the second shaft portion are connected to each other via an orthogonal surface orthogonal to the axis, similarly to the punch shown in FIG. Because it becomes. On the other hand, 45
If the angle is more than °, the material on the second shaft portion side is unlikely to flow smoothly to the first shaft portion side, and the effect of the present invention is hardly produced. 20-40 ° when forging a steering pinion
It is preferable to use an inclined surface.

(2) In addition, the present inventors have proposed a second shaft portion of the first shaft portion.
In order to prevent the end of the shaft portion from cracking, the first
It has been found that it is also effective to form a cylindrical surface on the shaft portion side, and the second invention has been completed. That is, the multi-stage inner groove member forging punch according to claim 2 is a multi-stage inner groove member forging punch for forming a multi-stage inner groove member in a rough material in a single step to obtain a multi-stage inner groove member. A first shaft portion on which the forming portion is formed, the first shaft portion being continuous with the first shaft portion on the insertion direction side, having a smaller diameter than the first shaft portion, and having a cylindrical surface formed on the first shaft portion side; And a second shaft portion having a second groove forming portion formed on the insertion direction side.

According to the second aspect of the present invention, the multi-stage inner groove can be formed with high coaxiality. Further, when the punch according to claim 2 is pressed into the coarse material, the flow of the material caused by the first groove forming portion of the first shaft portion is stopped by the cylindrical surface of the second shaft portion, and the second groove of the second shaft portion. Does not interfere with the material produced by the formation. For this reason, since the stress concentration due to the interference of the material of the punch is suppressed, the punch is less likely to crack at the end of the first shaft on the side of the second shaft.

[0012] In the punch according to the second aspect, the first shaft portion and the second shaft portion are continuous with each other through an inclined surface exceeding 0 ° and less than 90 ° with respect to the axis on the insertion direction side. it can. Claim 2
When an inclined surface is provided in the punch of the present invention, the inclined surface preferably exceeds 0 ° and 45 ° with respect to the axis as in the first aspect.
It is as follows. In particular, when forging a steering pinion, it is preferable to form a slope of 20 to 40 °. Further, the cylindrical surface according to claim 2 is preferably 5 to 15 mm in length when forging a steering pinion.

The punches according to the first and second aspects of the present invention can be used in a forging method in which a drilling step is performed in addition to a forging method in which a drilling step of providing a cylindrical prepared hole is not performed.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; Here, an inner spline will be described as an example of the inner groove. (Embodiment 1) As shown in FIG. 1, a punch 1 for forging a two-stage inner spline member according to Embodiment 1 has a first shaft portion 2 and the first shaft portion 2 with respect to the shaft center on the insertion direction side. The second shaft portion 4 is continuous with the 30 ° inclined surface 3 and has a smaller diameter than the first shaft portion 2.

On the peripheral surface of the first shaft portion 2, a first spline forming portion 2a as a first groove forming portion is formed. As shown in FIG. 3, the first spline forming portion 2a has a land 2b on the inclined surface 3 side, and the rear of the land 2b (the direction opposite to the insertion direction; the same applies hereinafter) is allowed to escape. Further, as shown in FIG. 1, a second spline forming portion 4 a as a second groove forming portion is formed on a peripheral surface of the second shaft portion 4. As shown in FIG. 4, the second spline forming portion 4a has a land 4b on the front side, and the rear of the land 4b is set to 0.01 to 0.
A release Δ of 05 mm is set. The land behind the escape Δ is the return of the land 4b.

Further, as shown in FIG. 1, on the inclined surface 3, the first spline forming portion 2a and the second spline forming portion 4a are continuous. The punch 1 is pressed into a columnar coarse material W made of carbon steel. Thereby, as shown in FIG. 2, the large-diameter valve spline S1 formed by the first spline forming portion 2a and the second spline forming portion 4a
Diameter manual stopper spline S formed by
2 can be obtained in one step. Therefore, the valve spline S1 and the manual stopper spline S2 can be formed with high coaxiality. At this time, a guide surface 5 is formed by the inclined surface 3 in front of the valve spline S1.

When the punch 1 was pressed into the coarse material W, the material on the second shaft portion 4 flowed smoothly to the first shaft portion 2 on the inclined surface 3. In particular, since the first spline forming portion 2a and the second spline forming portion 4a were continuous on the inclined surface 3, the material flowed smoothly. Therefore, the stress concentration due to the flow resistance of the punch 1 was reduced, and no crack occurred at the end of the first shaft 2 on the side of the second shaft 4.

Further, in the punch 1, no crack was generated at the rear of the land 4b of the second shaft portion 4 at the time of pulling.
This is because the return behind the release Δ suppresses the intrusion of the material into the release Δ. Therefore, according to the punch 1, the steering pinion W can be mass-produced with high accuracy.

In the steering pinion W shown in FIG. 2 obtained by the punch 1, after the upper portion of the manual stopper spline S2 is cut into a cylindrical surface by a predetermined process, as shown in FIG. Since the surface 5 could suitably guide the bearing needle 6 of the valve shaft 7 and be suitably positioned above the manual stopper spline S2, the valve shaft 7 could be quickly assembled. (Comparative Embodiment 1) A pinion W for steering is obtained in one step as in Embodiment 1 using a punch 80 for forging a two-stage inner spline member shown in FIG. Here, as shown in FIG. 11, the release Δ of the punch 80 behind the land 91b.
Is 0.1 to 0.2 mm.

When this punch 80 is used, as shown in FIG. 10, although the valve spline S1 and the manual stopper spline S2 can be formed with high coaxiality, as shown in FIG. At the time of pushing, a crack C was generated at the end of the first shaft 90 of the punch 80 on the second shaft 91 side. At this time, as shown in FIG. 10, a step 8 is formed in front of the valve spline S1 by an orthogonal surface 92.

Further, in the punch 80, as shown in FIG.
As shown in FIG.
b The crack C was also likely to be formed behind. According to the investigation of the cause of the inventor, as shown in FIG.
Is excessively large, and the material filled with the release Δ is squeezed, whereby a tensile stress acts on the rear of the land 91b.

Therefore, according to the punch 80, the pinion W for steering cannot be mass-produced with high accuracy. Then, in the steering pinion W obtained by the punch 80 shown in FIG.
As shown in (A), the step 8 easily prevents the movement of the bearing needle 6 of the valve shaft 7, so that the valve shaft 7 cannot be quickly assembled. (Comparative Embodiment 2) A punch 70 for forging a two-step inner spline member of Comparative Embodiment 2 has a first shaft portion 72 as shown in FIG.
The first shaft portion 72 and the shaft center on the insertion direction side with respect to the shaft center.
And a second shaft portion 74 having a smaller diameter than the first shaft portion 72.

On the peripheral surface of the first shaft portion 72, a first spline forming portion 72a as a first groove forming portion is formed. Like the first embodiment, the first spline forming portion 72a has a land (not shown) on the side of the inclined surface 73, and makes the rear of the land escape. A second spline forming portion 74a as a second groove forming portion is formed on a front peripheral surface of the second shaft portion 74. The second spline forming portion 74a has a land (not shown) on the front side as in the first embodiment, and the rear of the land has a clearance of 0.01 to 0.2 mm. In addition,
The back of the escape is the return of the land.

However, unlike the first embodiment, the first spline forming portion 72a and the second spline forming portion 74a are not continuous on the inclined surface 73. When the punch 70 is used, since the inclined surface 73 is at an angle of 60 ° with respect to the axis and the first spline forming portion 72a and the second spline forming portion 74a are not continuous, the second shaft portion 74 is not used.
The material on the side was difficult to flow smoothly to the first shaft portion 12 side.

In the case where the punch 70 is used, FIG.
As shown in FIG. 4, from the relationship of the processing degree (cross-section reduction rate),
The first spline forming portion 72a of the first shaft portion 72
There is a flow of material in the direction. Further, due to the backward extrusion, the material flows in the B direction by the second spline forming portion 74a of the second shaft portion 74. For this reason, the second shaft portion 7
In the punch 70, cracks C may occur at the end of the second shaft portion 74 on the first shaft portion 72 side due to stress concentration on the first shaft portion 72 side. Such a phenomenon could be caused not only by a forging method that does not perform a drilling step of providing a cylindrical prepared hole but also by a forging method that performs a drilling step. (Embodiment 2) As shown in FIG. 5, a two-stage inner spline member forging punch 10 of Embodiment 2 includes a first shaft portion 12 and
The first shaft portion 12 includes a second shaft portion 14 which is continuous with the first shaft portion 12 via an inclined surface 13 at an angle of 60 ° with respect to the shaft center on the insertion direction side and has a smaller diameter than the first shaft portion 12.

On the peripheral surface of the first shaft portion 12, a first spline forming portion 12a as a first groove forming portion is formed. Like the first embodiment, the first spline forming portion 12a has a land (not shown) on the inclined surface 13 side, and the rear of the land is made to escape. As shown in FIG. 8, an axial length l = 5 to 15 m is provided on the first shaft portion 12 side of the second shaft portion 14.
m cylindrical surface 14a is formed, and a second spline forming portion 1 as a second groove forming portion is formed on a peripheral surface in front of the cylindrical surface 14a.
4b is formed. The outer diameter of the cylindrical surface 14a is D _0. The second spline forming portion 14b has a land (not shown) on the front side as in the first embodiment, and the rear of the land has a relief of 0.01 to 0.2 mm. The land behind the escape is the return of the land.

Then, as shown in FIG. 6, first, as a drilling step, a cylindrical prepared hole W1 is provided in a columnar coarse material W. The inner diameter D ₁ of the the lower hole W1, the outer diameter D ₀ of the cylindrical surface 14a
Is set so that 0.2> D ₁ −D ₀ > 0.

Next, as shown in FIGS. 7 and 8, the punch 10 is pressed into the coarse material W. Thus, a steering pinion W having a large-diameter valve spline S1 formed by the first spline forming portion 12a and a small-diameter manual stopper spline S2 formed by the second spline forming portion 14a is obtained in one step. Therefore, the valve spline S1 and the manual stopper spline S
2 can be formed with high coaxiality. At this time, the guide surface 5 is formed by the inclined surface 13 in front of the valve spline S1.

When the punch 10 is pushed into the coarse material W, the flow of the material in the direction A caused by the first spline forming portion 12a of the first shaft portion 12 is caused by the frictional resistance of the cylindrical surface 14a of the second shaft portion 14. Stopped by the force F, the second shaft 14
Does not interfere with the material in the B direction generated by the second spline forming portion 14b. For this reason, since the stress concentration due to the interference of the material of the punch 10 is suppressed, the second shaft
Cracks C are less likely to occur at the end of the shaft 14.

Therefore, the punch 10 also
The pinion W for steering can be mass-produced with high accuracy. In the steering pinion W shown in FIG. 8 obtained by the punch 10, since the cylindrical surface is formed on the upper portion of the manual stopper spline S2 by the cylindrical surface 14a, the upper portion of the manual stopper spline S2 as in the first embodiment is formed. It is not necessary to perform a predetermined process of cutting the cylindrical surface into a cylindrical shape. For this reason, the deburring by performing the intermittent cutting as in the first embodiment becomes unnecessary, and the concern about the early deterioration of the tool due to the intermittent cutting as in the first embodiment can be solved. And FIG.
As shown in (B), since the guide surface 5 can suitably guide the bearing needle 6 of the valve shaft 7 and can be suitably positioned above the manual stopper spline S2, the valve shaft 7 can be quickly assembled. Was completed.

In the first and second embodiments, the two-stage internal spline member forging punch 1 in which the two shaft portions 2, 4, 12, 14 are continuous with the inclined surfaces 3, 13 is claimed. However, three or more shaft portions can be continuous. Then, a multi-step inner groove member having three or more inner grooves in one step can be obtained.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a punch according to a first embodiment.

FIG. 2 is a sectional view of a steering pinion obtained by a punch according to the first embodiment.

FIG. 3 is a partially enlarged cross-sectional view of the punch according to the first embodiment.

FIG. 4 is a partially enlarged cross-sectional view of the punch according to the first embodiment.

FIG. 5 is a partial cross-sectional view of a punch according to a second embodiment.

FIG. 6 is a partial cross-sectional view of a rough material using the punch according to the second embodiment.

FIG. 7 is a partial cross-sectional view of a punch and a coarse material according to a second embodiment.

FIG. 8 is a partial sectional view of a punch and a coarse material according to a second embodiment.

FIG. 9 is a partial cross-sectional view of the punch of Comparative Embodiment 1.

FIG. 10 is a cross-sectional view of a steering pinion obtained by a punch of Comparative Embodiment 1.

FIG. 11 is a partially enlarged cross-sectional view of the punch of Comparative Embodiment 1.

FIGS. 12A and 12B are partially enlarged cross-sectional views of a punch according to Comparative Embodiment 1 when pressed, and FIG. 12B is a partially enlarged cross-sectional view when pulled out.

FIG. 13 is a partial cross-sectional view of a punch of Comparative Embodiment 2.

FIG. 14 is a partial cross-sectional view of a punch and a coarse material according to Comparative Embodiment 2.

FIG. 15A is a steering pinion obtained by a punch of Comparative Embodiment 1, and FIG. 15B is a steering pinion obtained by a punch of Embodiments 1 and 2; It is a partially enlarged sectional view.

[Explanation of symbols]

 1, 10 punch 2, 12 first shaft portion 2a, 12a first spline forming portion (first groove forming portion) S1 valve spline 3, 13 inclined surface 4, 14 second shaft portion 14a cylindrical Surfaces 4a, 14b: second spline forming portion (second groove forming portion) S2: manual stopper spline W: coarse material, steering pinion (inner groove member)

Claims (2)

[Claims] 1. A multi-stage inner groove member forging punch for forming a multi-stage inner groove member in a rough material in a single step, wherein the first shaft portion having a first groove forming portion formed therein. A second shaft portion continuous with the first shaft portion via an inclined surface of 45 ° or less with respect to the axis on the insertion direction side, and having a second groove forming portion having a smaller diameter than the first shaft portion. And a punch for forging a multi-stage internal groove member. 2. A multi-stage inner groove member forging punch for forming a multi-stage inner groove member in a rough material in one step, wherein the first shaft portion having a first groove forming portion formed therein. And a second groove formed on the side of the first shaft portion that is smaller in diameter than the first shaft portion, has a cylindrical surface on the side of the first shaft portion, and is formed on the side of the insertion direction from the cylindrical surface. And a second shaft portion having a portion formed therein.