JP2016117120A - Broach processing tool and broach processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a broach processing tool and a broach processing method, capable of processing a high-quality cut surface, and using an existing facility as it is as a facility to be used.SOLUTION: In a broach processing tool, a plurality of cutting blades are arrayed along a tool sending direction. A cutting blade for final finishing is provided on an arrangement position out of contact with a cut surface simultaneously with a cutting blade just prior to the cutting blade for final finishing.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a broaching tool and a broaching method.

  Broach tools are widely used for pocket hole machining in cages of constant velocity universal joints in terms of tool life and dimensional accuracy stability (Patent Document 1). As shown in FIGS. 6A and 6B, a general broaching tool has a plurality of cutting blades in which a roughing cutting blade 1 and a finishing cutting blade 2 are combined.

  As shown in FIG. 7, the roughing cutting edge 1 has a height dimension H that increases sequentially from the upstream side to the downstream side in the tool feed direction. That is, the height dimension of the most rough cutting edge 1A is h1, the height dimension of the next roughing cutting edge 1B is h2, and the height dimension of the next roughing cutting edge 1C is h3. In the following, when h4 to h10 are sequentially set, h1 <h2 <h3. On the other hand, as shown in FIG. 8, the height dimension hf of each cutting edge 2 for finishing is set to the same dimension. In this case, the broaching tool is formed of a square bar, and the roughing cutting blade 1 is formed only on the two opposite side surfaces 5a, 5c among the four side surfaces 5a, 5b, 5c, 5d. For this reason, the roughing cutting blade 1 is formed with a plurality of blades at a predetermined pitch along the axial direction on each of the side surfaces 5a and 5c.

  The roughing cutting blades 1 are arranged at a predetermined constant pitch along the tool feed direction. At the time of machining, the cutting blades that come into contact with the workpiece (workpiece) as the broach tool moves. The number will fluctuate. In the case shown in FIG. 6, there are two or three blades. Such variation in the number of cutting edges means variation in cutting resistance. This variation in cutting resistance does not adversely affect the dimensional accuracy, but it is difficult to form a high-quality cutting surface.

  By the way, in broaching, a tool having a cutting edge 1 arranged so as to increase sequentially from the front to the back in the tool feed direction is pressed against the work piece to form a hole (for example, a pocket hole of a constant velocity universal joint retainer). ) Is a process that expands. However, the final dimensions and cutting surface properties are determined after finishing the diameter expansion by the roughing cutting blades 1 arranged so as to increase sequentially from the front to the rear in the tool feed direction. It is several cutting blades 2 for finishing which do not change the cutting blade height.

  Incidentally, in FIG. 6, the axial length S1 in the range S is the thickness of the workpiece (workpiece thickness). For this reason, also in the cutting edge 2 for finishing, the number of cutting edges which contact a workpiece (workpiece) fluctuates, and it is difficult to form a high-quality cutting surface. Therefore, conventionally, there is a broach tool that focuses on cutting resistance fluctuation (Patent Document 2).

  In Patent Document 2, a raised portion that supports the back force of the cutting force applied to the cutting edge is formed on the flank of the cutting edge, and this raised portion is located on the rear side in the tool feed direction from the cutting edge of the cutting edge. It is gradually increased toward.

  For this reason, when the cutting edge which has a protruding part passes the workpiece, the cutting surface by this cutting edge and a protruding part contact. Thereby, since the back component force of the workpiece is supported, vibration and movement of the workpiece can be suppressed, and fluctuations in the back component force can be suppressed. Thus, according to the broaching tool, the machining accuracy can be increased because the cutting can be performed in a stable state.

JP-A-53-56442 Japanese Patent No. 5444778

  However, in the thing of the said patent document 2, since the shape of a cutting edge is complicated, there exists a difficulty of design, the difficulty of the process (blade attachment) of a blade, the difficulty of regrinding, etc., and a tool unit price is high. It will be a thing. In addition, since the design of the raised portion differs depending on the material of the workpiece, there is a problem that one product is required to be designed.

  Therefore, the present invention provides a broaching tool and a broaching method that can machine a high-quality cutting surface and that can use existing equipment as it is.

  The broaching tool of the present invention is a broaching tool in which a plurality of cutting blades are arranged along the tool feed direction, and the cutting blade for final finishing is immediately before the cutting blade for final finishing. At the same time, it is provided at an arrangement position that does not contact the cutting surface.

  According to the broaching tool of the present invention, the cutting edge immediately before does not come into contact with the cutting surface in the state of cutting with the cutting blade for final finishing. For this reason, in the finishing process which cuts with the cutting blade for finishing, variation in cutting resistance is not caused. Further, since it is only necessary to change the arrangement pitch of the cutting blade for final finishing as compared with the existing broaching tool, the cutting blade shape does not become a complicated shape. And the pitch between the cutting blade for final finishing of the cutting blade for finishing and the cutting blade immediately before it can be easily calculated from the thickness dimension of the workpiece (workpiece) and the specifications of the cutting blade.

  It is preferable that a plurality of roughing cutting edges are provided in front of the finishing cutting edge in the tool feeding direction, and the roughing cutting edges are configured so as to sequentially increase from the front to the rear in the tool feeding direction. With the cutting edge for rough machining, the hole of the workpiece (for example, the pocket hole of the cage of the constant velocity universal joint) can be enlarged. Thus, the broaching tool can be used for finishing the inner surface of the pocket of the cage of the constant velocity universal joint.

  The broaching method of the present invention is a processing method in which a workpiece is broached with a broaching tool, and is cut with a final finishing cutting edge with respect to the final finishing cutting edge. In this way, the last cutting edge is finished without contacting the cutting surface.

  According to the broaching method of the present invention, the cutting edge for final finishing is not brought into contact with the cutting surface with respect to the cutting edge for final finishing while cutting with the cutting edge for final finishing. In the finishing process of cutting with a blade, the cutting resistance does not fluctuate.

  In the present invention, since the cutting resistance is not changed in the finishing process of cutting with the cutting blade for finishing, it is possible to obtain a cutting surface quality free from chatter and stuffiness. Moreover, since the shape of the cutting edge does not become a complicated shape, it does not have the disadvantages of the conventional one formed with a raised portion that supports the back force of the cutting resistance applied to the cutting edge. This broaching tool can easily calculate the pitch between the final finishing cutting edge and the immediately preceding cutting edge from the thickness dimension of the workpiece (workpiece) and the specifications of the cutting edge. The cutting edge processing is not special, so it has excellent productivity. Furthermore, even if it is not compared with existing conventional ones, only the pitch between the cutting blade for final finishing and the cutting blade immediately before it is different, and it can be used with existing broaching machines and is special. A high-quality cutting surface can be obtained at low cost without the need for a processing machine or an accessory device.

It is a principal part top view of the broaching tool of this invention. It is an expanded sectional view of the cutting blade for rough machining of the broaching tool of the said FIG. It is an enlarged view of the cutting blade for finishing of the broaching tool of the said FIG. It is a perspective view of the 1st broaching tool. It is a perspective view of the holder | retainer of the constant velocity universal joint broached with the broaching tool of this invention. It is a principal part top view of the conventional broaching tool. It is an expanded sectional view of the cutting blade for roughing of the conventional broaching tool. It is an enlarged view of the cutting blade for finishing of the conventional broaching tool.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. This broaching tool is for processing (finishing) the inner surface of the pocket 21 of the cage 20 of a constant velocity universal joint as shown in FIG. A plurality of cutting edges 11 for rough machining disposed at equal intervals at a predetermined pitch, and on the downstream side in the machining progress direction (the rear side in the tool feed direction) with respect to the plurality of cutting edges 11 for rough machining. And a plurality of finishing cutting edges 12 disposed. In this case, the broaching tool includes a distal end side shaft portion 13 where the roughing cutting edge 11 is formed, an intermediate shaft portion 14 formed on the finishing cutting edge 12, and a proximal end side grip portion 15. Become.

  As with the broaching tool shown in FIG. 5, the roughing cutting edge 11 has a height dimension H that increases sequentially from the upstream side (front side) to the downstream side (rear side) in the tool feed direction. That is, as shown in FIG. 2, the height dimension of the most cutting edge 11A for rough machining is set to H1, the height dimension of the next cutting edge 11B for rough machining is set to H2, and the next roughing edge is set. When the height dimension of the cutting edge 11C for processing is H3, and H4 to H10 in order, H1 <H2 <H3... <H10. In this case, the roughing cutting blade 1 is formed only on the two opposite side surfaces 10a, 10c among the four side surfaces 10a, 10b, 10c, 10d of the distal end side shaft portion 13. For this reason, the cutting edge 11 for rough machining is formed with a plurality of blades at a predetermined pitch along the axial direction on each of the side surfaces 10a and 0c. The roughing cutting edge 11 is inclined at a predetermined angle with respect to a plane orthogonal to the tool axis.

  The cutting edges 12 for finishing are formed on all four side surfaces, and in this embodiment, three sheets are arranged at equal pitches from the upstream side (front side) to the downstream side (rear side) in the tool feed direction. Cutting blades 12A, 12B, and 12C for finishing, and a fourth cutting blade 12D for finishing that is spaced from the cutting blade 12C for finishing. The cutting edge 12 for finishing on each side is continuous in the circumferential direction.

  That is, as shown in FIG. 3, the pitch between the edge 13a of the distal end side shaft portion 13 and the first finishing blade 12A is P1, and the first finishing blade 12A and the second finishing blade 12A The pitch between the finishing cutting edge 12B is P2, and the pitch between the second finishing cutting edge 12B and the third finishing cutting edge 12C is P3. When the pitch between the blade 12C and the fourth finishing blade 12D is P4, and the distance between the fourth finishing blade 12D and the edge 15a of the grip portion 15 is P5, P1 = P2 = P3 = P5 <P4. Further, the height dimension HF of the finishing blades 12A, 12B, 12C, and 12D is set to the same dimension.

  By the way, as for this broaching tool, the arrow X direction shown in FIG. Therefore, the fourth finishing cutting edge 12D is the final finishing cutting edge, and the third finishing cutting edge 12C is the cutting edge immediately before the final finishing cutting edge 12D. Further, the axial length S1 in the range S of FIG. 1 is the thickness of the workpiece (workpiece thickness).

  Therefore, as the pitch P4 between the third finishing cutting edge 12C and the fourth finishing cutting edge 12D, the final finishing cutting edge 12D is set to the final finishing cutting edge 12D. It is set as the pitch used as the arrangement position which does not contact a cutting surface simultaneously with the cutting edge 12C immediately before. That is, S1 <P4.

  Next, a method for broaching using the broaching tool configured as described above will be described. In this case, when compared with the conventional broaching tool shown in FIG. 5, the broaching tool according to the present invention has a pitch between the third finishing cutting edge 12C and the fourth finishing cutting edge 12D. P4 is only different from the other pitches P2 and P3 between the cutting edges for finishing. For this reason, an existing publicly known broaching machine (not shown) can be used as a broaching machine on which this broaching tool is to be mounted.

  Since this broaching is for finishing the pocket 21 of the cage 20 of the constant velocity universal joint as shown in FIG. 5 in the embodiment, first, a metal material such as chrome steel is machined, A workpiece (work), which is a cylindrical intermediate product, is formed. The thickness dimension of the workpiece is S1. After that, a guide hole as a pilot hole is made in the workpiece, a broaching tool mounted on the broaching machine is inserted into the guide hole, and the broaching tool is inserted into the guide hole along the axis direction of the arrow X Push along the direction. As a result, the guide holes are sequentially enlarged by the roughing cutting blade 1, and the hole to be processed, that is, the inner surface of the pocket 21 of the cage 20 of the constant velocity universal joint can be finished by the finishing cutting blade 2. it can.

  In this case, in this broaching tool, the final finishing cutting edge 12D is arranged so as not to contact the cutting surface (inner diameter surface of the hole to be processed) simultaneously with the cutting blade 12C immediately before the final finishing cutting edge 12D. Since it is provided at the position, the cutting edge 12C immediately before does not come into contact with this cutting surface in the state of cutting with the final finishing cutting edge 12D.

  As described above, in the present invention, since the cutting resistance is not changed in the finishing process of cutting with the cutting edge 12 for finishing, it is possible to obtain a cutting surface quality free from chatter and stuffiness. In addition, as compared with the existing broaching tool, since only the arrangement pitch of the cutting blade for final finishing is changed, the cutting blade shape does not become a complicated shape. For this reason, there are advantages such as easy design of the cutting edge shape, easy processing (blade attachment) of the blade, easy re-grinding, and low tool unit cost.

  This broaching tool can easily calculate the pitch between the final finishing cutting edge and the immediately preceding cutting edge from the thickness dimension of the workpiece (workpiece) and the specifications of the cutting edge. The cutting edge processing is not special, so it has excellent productivity. Furthermore, even if compared with the existing conventional ones, it is only necessary to make the pitch between the cutting blade for final finishing processing and the cutting blade immediately before that different, so that it can be used with an existing broaching machine and is special. A high-quality cutting surface can be obtained at low cost without the need for a processing machine or an accessory device.

  By the way, in the broaching tool of the said embodiment, although it consists of a square bar (square bar), it may consist of a round bar. That is, as the bleaching tool of the present invention, various tools such as a round broach for processing a round hole, a square broach for processing a square hole, and a key groove broach for processing a key groove can be configured.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications can be made. As the number of roughing cutting blades 11 and finishing cutting blades 12, It is not limited to the example shown in the figure, and their increase and decrease are arbitrary, and the cutting pitch for final finishing 12D is the cutting pitch immediately before the cutting blade 12D for final finishing as the arrangement pitch of each blade. It suffices that the blade 12C can be provided at an arrangement position that does not contact the cutting surface simultaneously. That is, various changes can be made according to the thickness dimension and material of the workpiece. In addition, what is finished is not limited to the pocket 21 of the cage 20 of the constant velocity universal joint, as long as it can be finished with various broaches as described above.

11 (11A, 11B, 11C) Cutting edge 12 for rough machining (12A, 12B, 12C) Cutting edge for finishing

Claims (4)

A broaching tool in which a plurality of cutting blades are arranged along the tool feed direction,
A broaching tool characterized in that the final finishing cutting edge is provided at a position where it does not contact the cutting surface simultaneously with the cutting edge immediately before the final finishing cutting edge.   2. A plurality of roughing cutting blades are provided in front of the tool cutting direction with respect to the finishing cutting blade, and the roughing cutting blades are sequentially raised from the front to the rear in the tool feeding direction. Broaching tool as described in 1.   The broaching tool according to claim 1 or 2, wherein the broaching tool is used for finishing the inner surface of the pocket of the cage of the constant velocity universal joint. A processing method for performing broaching on a workpiece with a broaching tool,
A processing method comprising: finishing with a cutting blade for final finishing without contacting the cutting surface immediately before the cutting blade for final finishing with the cutting blade for final finishing.

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