Rolling flat die

Abstract

To provide a rolling flat die that can suppress deformation of a hollow hole part after rolling in a rolling process on a hollow cylindrical workpiece without adding a pre-process before rolling and also in a processing cycle similar to that on a solid cylindrical workpiece and can achieve good rolling accuracy.SOLUTION: In a rolling flat die 100 including chamfer portions 11 and 12 equipped with processing teeth for performing a rolling process on a workpiece, and a finishing portion 20 equipped with processing teeth for continuously performing the rolling process on the workpiece, the chamfer portions 11 and 12 are formed such that the front chamfer portion 11 is located at the front side in the moving direction of the flat die 100 and the rear chamfer portion 12 is formed at the rear side. The front chamfer portion 11 and the rear chamfer portion 12 are arranged along the width direction of the flat die 100 such that the terminal position of the front chamfer portion 11 and the starting position of the rear chamfer portion 12 coincide with each other in the longitudinal direction of the flat die 100.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rolling die for rolling a gear such as a spline tooth profile into a workpiece. [Background technology]

[0002] Conventionally, in the rolling of gears using flat rolling dies, various flat rolling dies and rolling methods using them have been disclosed (see Patent Documents 1 and 2). However, these flat dies are intended for solid cylindrical workpieces, and there is a problem in that the hollow hole portion is significantly deformed by the large load during rolling when rolling a hollow cylindrical workpiece.

[0003] In view of this, several rolling methods for hollow cylindrical workpieces have been disclosed. For example, Patent Document 3 discloses a rolling method using a round die. Also, Patent Document 4 discloses a rolling method for hollow cylindrical workpieces using a core bar in the hollow part. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 6-106286 [Patent Document 2] Publication number 2-27950 [Patent Document 3] Japanese Patent Application Publication No. 5-69074 [Patent Document 4] Patent No. 5183116 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the rolling process using a round die as disclosed in Patent Document 1, the rolling machine used becomes larger, leading to increased costs and lead times. In addition, in the rolling process using a core bar as disclosed in Patent Document 2, a process of removing the core bar is required after the process is completed, which also increases the processing time. At the same time, there is a possibility that the hole diameter of the hollow part will widen, and in order to ensure the hole diameter of the hollow part, there are certain restrictions on the material and thickness of the workpiece.

[0006] Therefore, an object of the present invention is to provide a flat die for rolling that can suppress deformation of the hollow hole portion after rolling and achieve good rolling accuracy in the rolling of a workpiece (especially a hollow cylindrical workpiece) without adding a pre-process (preparation process) before the rolling and even with a processing cycle similar to that for a solid cylindrical workpiece. [Means for solving the problem]

[0007] The flat rolling die of the present invention has a chamfering portion with multiple working teeth that first rolls the workpiece, and a finishing portion with multiple working teeth formed contiguous to the chamfering portion and subsequently rolling the workpiece, the chamfering portion being formed from a front chamfering portion disposed on the front side in the moving direction of the flat rolling die, and a rear chamfering portion disposed on the rear side in the moving direction of the flat rolling die. These front chamfering portion and rear chamfering portion are disposed along the width direction of the flat rolling die, and are disposed such that the end position of the front chamfering portion and the start position of the rear chamfering portion coincide with each other in the longitudinal direction of the flat rolling die.

[0008] The front chamfer is formed of a first front chamfer and a second front chamfer, and the first front chamfer and the second front chamfer are spaced apart from each other in the width direction of the flat die for rolling. The rear chamfer is formed of a first rear chamfer and a second rear chamfer, and the first rear chamfer and the second rear chamfer are spaced apart from each other in the width direction of the flat die for rolling, and the start positions of the first front chamfer and the second front chamfer in the longitudinal direction of the flat die for rolling are arranged to coincide with the start position of the flat die for rolling. In addition, the end positions of the first and second front chamfers and the start positions of the first and second rear chamfers may be arranged to coincide. The ridge of either the front chamfer or the rear chamfer may be curved in a side view or a cross-sectional view in the longitudinal direction of the flat die for rolling. Effect of the Invention

[0009] The flat rolling die of the present invention can suppress deformation of the hollow hole during rolling of a hollow cylindrical workpiece, thereby achieving good rolling accuracy, and at the same time, can significantly shorten the overall length of the flat rolling die (die length). [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic plan view of a flat die 100 for rolling according to the present invention. [Diagram 2] 2 is a schematic cross-sectional view of the rolling flat die 100 taken along line XX shown in FIG. [Diagram 3] 2 is a schematic cross-sectional view of the rolling flat die 100 taken along line YY shown in FIG. [Figure 4] 2 is a schematic cross-sectional view of the rolling flat die 100 taken along line AA in FIG. 1. [Diagram 5] 2 is a schematic cross-sectional view of the rolling flat die 100 taken along line BB shown in FIG. [Figure 6] 2 is a schematic cross-sectional view of the rolling flat die 100 taken along line CC shown in FIG. [Figure 7] 2 is a schematic cross-sectional view of the rolling flat die 100 taken along line DD shown in FIG. [Figure 8] 2 is a schematic cross-sectional view of the rolling flat die 100 taken along line EE shown in FIG. [Figure 9] 4 is a schematic enlarged view of each of the processing teeth 41, 42 of the front and rear chamfering portions. FIG. [Figure 10] 4 is a schematic enlarged view of the machining teeth 51, 52 of the finishing portion. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An embodiment of the flat die for rolling according to the present invention will be described with reference to the drawings. A schematic plan view of a flat die for rolling 100 according to one embodiment of the present invention is shown in FIG. 1, a schematic cross-sectional view taken along line XX in FIG. 2, and a schematic cross-sectional view taken along line YY in FIG. 3. The flat die for rolling 100 according to the present invention is divided into three parts along the movement direction M from the front side to the rear side during rolling: a chamfering part 11, 12 having a plurality of processing teeth that first performs rolling on the workpiece, a finishing part 20 having a plurality of processing teeth formed continuously from the chamfering part 11, 12 and performing subsequent rolling on the workpiece, and a relief part 30.

[0012] The chamfers 11, 12 are formed from a front chamfer 11 disposed on the front side in the moving direction of the rolling flat die 100 and a rear chamfer 12 disposed on the rear side in the moving direction of the rolling flat die 100. The front chamfer 11 and the rear chamfer 12 are disposed along the width direction of the rolling flat die 100 as shown in Fig. 1, and are disposed so that the end position where the rolling by the front chamfer 11 is completed and the start position where the rolling by the rear chamfer 12 is started coincide with each other in the longitudinal direction of the rolling flat die 100.

[0013] The front chamfer 11 is formed of a first front chamfer 11A and a second front chamfer 11B as shown in Fig. 1, and the first front chamfer 11A and the second front chamfer 11B are arranged spaced apart from each other in the width direction of the rolling flat die 100. The processing teeth 41A of the front chamfer 11 (first front chamfer 11A) are formed from one end side of the rolling flat die 100 as shown in Fig. 2, and are formed to continue to the processing teeth 51A of the finishing section 20 on the rear side along the longitudinal direction (the direction of movement during rolling).

[0014] The rear chamfer 12 is formed from a first rear chamfer 12A and a second rear chamfer 12B as shown in FIG. 1, and the first rear chamfer 12A and the second rear chamfer 12B are arranged spaced apart from each other in the width direction of the rolling flat die 100, and are arranged so that the starting position at which rolling by the first front chamfer and the second front chamfer in the longitudinal direction of the rolling flat die 100 begins coincides with the starting position at which rolling by the rolling flat die begins, and so that the terminal position at which rolling by the first and second front chamfers is completed coincides with the starting position at which rolling by the first and second rear chamfers begins.

[0015] In addition, the processing teeth 42B of the rear cutting portion 12 (second rear cutting portion 12B) are formed at a position spaced a certain distance from one end side of the flat die 100 for rolling processing as shown in Figure 3, and are formed on the rear side along the longitudinal direction (the direction of movement during rolling processing) continuous with the processing teeth 52B of the finishing portion 20.

[0016] Next, a schematic cross-sectional view of the rolling die 100 shown in Fig. 1 taken along line AA is shown in Fig. 4, a schematic cross-sectional view of the same shown along line BB is shown in Fig. 5, a schematic cross-sectional view of the same shown along line CC is shown in Fig. 6, a schematic cross-sectional view of the same shown along line DD is shown in Fig. 7, and a schematic cross-sectional view of the same shown along line EE is shown in Fig. 8. The cross-sectional views shown in Figs. 4 to 8 are cross-sectional views in a direction (the vertical direction in Fig. 1) perpendicular to the moving direction of the rolling die 100 during rolling (the direction of arrow M shown in Fig. 1).

[0017] As the front cutting portion 11 (first front cutting portion 11A and second front cutting portion 11B) approaches the finishing portion 20, the height (top surfaces of the cutting teeth) of the processing teeth 41A, 41B gradually increases as it approaches the finishing portion 20, as shown in Figures 4 and 5, and when the height of the processing teeth 41A, 41B of the first front cutting portion 11A and second front cutting portion 11B reaches the imaginary line LB of the top surfaces of the processing teeth 51A, 51B of the finishing portion 20, as shown in Figure 6, there is a complete transition from the front cutting portion 11 (first front cutting portion 11A and second front cutting portion 11B) to the finishing portion 20.

[0018] 6 and 7, the height of the processing teeth 42A, 42B of the rear chamfer 12 (first rear chamfer 12A and second rear chamfer 12B) gradually increases as the rear chamfer 12 (first rear chamfer 12A and second rear chamfer 12B) approaches the finishing section 20 from the position where the front chamfer 11 (first front chamfer 11A and second front chamfer 11B) completely transitions to the finishing section 20. Then, as shown in FIG. 8, when the height of the processing teeth 42A, 42B of the first rear chamfer 12A and second rear chamfer 12B reaches the imaginary line LB of the top surface of the processing teeth 52 of the finishing section 20, the rear chamfer 12 (first rear chamfer 12A and second rear chamfer 12B) completely transitions to the finishing section 20.

[0019] In other words, in the flat rolling die of the present invention, the front and rear chamfers which form the chamfer during rolling are arranged separately in the width direction of the flat rolling die, and by matching the position (timing) at which the rolling by the front chamfer is completed and the position (timing) at which the rolling by the rear chamfer is started, rolling is performed separately on the workpiece at different processing timings and at separate positions on the workpiece, and as a result, the processing load generated in the workpiece during rolling can be distributed.

[0020] In the flat die for rolling of this embodiment, as shown in Figure 9, the contours of the processing teeth 41, 42 of the front chamfering portion 11 and the rear chamfering portion 12 both have a curved shape when viewed from the side or in cross section in the longitudinal direction of the flat die for rolling 100, but it is sufficient that the contour of the processing teeth of at least one of the front chamfering portion or the rear chamfering portion has a curved shape when viewed from the side or in cross section in the longitudinal direction of the flat die for rolling.

[0021] Furthermore, the processing teeth 51, 52 of each finishing portion 20 formed continuously with the front chamfer 11 and the rear chamfer 12 may be curved in shape when viewed from the side or in cross section in the longitudinal direction of the rolling die 100, as shown in FIG. [Explanation of symbols]

[0022] 11, 11A, 11B Front chamfer 12, 12A, 12B Rear chamfer 20 Finishing Section 41 (41A, 41B) Front cutting teeth 42 (42A, 42B) Rear cutting teeth 51 (51A, 51B) Finishing teeth 52(52B) Finishing teeth 100 Flat die for rolling LB: Virtual line of the top surface of the finishing teeth M Direction of movement of the flat die for rolling

Claims

1. A flat die for rolling having at least a chamfering portion with a plurality of processing teeth that first performs rolling on the workpiece, and a finishing portion with a plurality of processing teeth formed contiguous to the chamfering portion and subsequently performs rolling on the workpiece, wherein the chamfering portion has a front chamfering portion arranged on the front side in the direction of movement of the flat die for rolling, and a rear chamfering portion arranged on the rear side in the direction of movement of the flat die for rolling, and the front chamfering portion and the rear chamfering portion are arranged along the width direction of the flat die for rolling, and are arranged so that the terminal position where the rolling by the front chamfering portion is completed and the starting position where the rolling by the rear chamfering portion begins coincide in the longitudinal direction of the flat die for rolling.

2. 2. The flat die for rolling as described in claim 1, wherein the front chamfer is formed from a first front chamfer and a second front chamfer, the first front chamfer and the second front chamfer being spaced apart from each other in the width direction of the flat die for rolling, the rear chamfer is formed from a first rear chamfer and a second rear chamfer, the first rear chamfer and the second rear chamfer being spaced apart from each other in the width direction of the flat die for rolling, and the starting position at which the first front chamfer and the second front chamfer begin in the longitudinal direction of the flat die for rolling is arranged to coincide with the starting position at which the flat die for rolling begins, and the flat die for rolling is arranged so that an end position at which the first and second front chamfers are completed and a starting position at which the first and second rear chamfer begin

3. 3. A flat die for rolling as described in claim 1 or 2, characterized in that the contour of at least one of the processing teeth of the front cutting edge portion or the rear cutting edge portion has a curved shape when viewed from the side of the flat die for rolling.

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