JP4442862B2 - Assembly type internal broach tool - Google Patents

Description

  The present invention relates to an assembly type internal broach tool for finishing a high hardness material having a hardness of 45 to 65 HRC.

Conventional assembly type internal broach tools are used for broaching of large-diameter internal gears and the like. Among these assembly-type inner surface broach tools, a blade type tool includes a plurality of blade-type broach tools in the longitudinal direction on the outer circumferential surface of a rod-shaped broach body 90 as shown in FIG. 4 (corresponding to FIG. 2 in Patent Document 1). The assembly-type inner surface broaching tool 100 in which a blade 93 having a finishing cutting edge 92 having the same longitudinal length as that of the groove 91 is fitted into each of the plurality of grooves 91 and fixed with a set bolt 94. There is. When high-hardness material having a hardness of 45 to 65 HRC (Rockwell hardness C scale: the same applies hereinafter) is broached with this assembly-type inner surface broach tool 100, the material of the blade 93 to be implanted in the broach body 90 is generally high. A material such as a cemented carbide used as a hard material may be used. The assembly-type inner surface broaching tool 100 having such a blade made of cemented carbide is shown in FIG. 3 when the entire length of the blade is long or when there is a lot of cutting work material (hereinafter referred to as a workpiece). As shown, a plurality of grooves 71 are provided in the longitudinal direction on the outer circumferential surface of the rod-shaped broach main body 70, and a first cemented carbide blade 75 having a cutting edge 73 in each of the plurality of grooves 71, The second cemented carbide blade 76 having the cutting edge 69 and the finishing cutting edge 72 may be configured to be an assembly-type inner surface broach tool 77 in which the second cemented carbide blade 76 is continuously implanted in the longitudinal direction. The first cemented carbide blade 75 is made of a cemented carbide material and is implanted along the rear side of the front guide 74 as viewed from the front grip 79. The cutting edge 73 is not necessarily provided with a finishing edge, and is provided with a rough edge or the like, and performs processing up to the finishing process performed by the subsequent blade. Similarly, the second cemented carbide blade 75 is also made of a cemented carbide material, and is implanted following the first cemented carbide blade 75 as viewed from the front grip portion 79. The workpiece is finished with the finishing blade 72 of the second cemented carbide blade 76.
Japanese Utility Model Publication No. 57-57876

  However, when the ball spline grooves 18, 19, and 20 of the workpiece 21 having the hardness of 45 to 65 shown in FIG. 2 are finished using the assembly type internal broach tool 77 shown in FIG. 3, the first cemented carbide is obtained. There is a slight possibility that the blade near the mating surface of the blade 75 and the second cemented carbide blade 76 will be chipped or cracked.

  The present invention has been made to solve the problems of the prior art, and is an assembly-type inner surface broach tool in which cemented carbide blades are continuously provided in the longitudinal direction in the groove of the broach body. An object of the present invention is to provide an assembly-type inner surface broaching tool that can process a hard material without cracking or chipping even if it is broached.

  As a result of studying the cracks and chips of the blades described above using a workpiece having a hardness of 60 HRC, the inventors have found that cracks and chips near the mating surface between the blades and the blades are made of alloy steel. However, we focused on the point that it tends to occur when the blade is made of cemented carbide. In other words, if the blade with a cutting edge is made of high-speed tool steel that has high toughness and does not cause brittle fracture, it can be processed without cracking or chipping even if it receives impact load due to processing vibration on the mating surface during broaching . However, when brittle materials such as cemented carbide are planted continuously, high stress is applied partially due to processing vibration during broaching, resulting in chipping and cracking in the vicinity of the mating surface between the blade and blade. I found out.

  Based on this knowledge, in the present invention, the buffer member is provided between the cemented carbide blades adjacent to each other in the longitudinal direction implanted in each groove. That is, in the invention according to claim 1 of the present invention, it is provided with a plurality of grooves provided in the longitudinal direction of the outer peripheral surface of the rod-shaped broach body and a plurality of cutting blades, and is detachably attached to the grooves. An internal broaching tool for finishing a workpiece having a hardness of 45 to 65 HRC, wherein a plurality of the cemented carbide blades are implanted in each of the plurality of grooves. In addition, the above-mentioned problems have been solved by providing an assembly-type inner surface broaching tool in which a buffer member is provided between cemented carbide blades adjacent to each other in the longitudinal direction and implanted in each groove. The buffer member is a member having sufficient strength and toughness as it does not cause brittle fracture itself when intermittent impact force is applied by broaching. More specifically, any material having elasticity that does not cause a gap between the buffer member and the adjacent cemented carbide blade during assembly of the assembly-type inner surface broach tool or broaching may be used. Examples of such a material include alloy steel, aluminum alloy, copper alloy, and resin. Among these, alloy steel has the above-mentioned properties best. It is suitable to use.

  Accordingly, when broaching a high hardness material having a hardness of 45 to 65 HRC, a plurality of grooves are provided in the longitudinal direction on the outer circumferential surface of the broach body, and the plurality of grooves are continuously provided in the longitudinal direction. By providing a buffer member between the hard alloy blade and the cemented carbide blade, brittle materials are not in direct contact with each other, and stress concentration on the cemented carbide blade can be reduced. No cracking or chipping occurs even when subjected to impact load due to machining vibration.

  As described above, according to the present invention, the carbide having a plurality of grooves provided in the longitudinal direction of the outer peripheral surface of the rod-shaped broach main body and a plurality of cutting edges and detachably attached to the grooves. An assembly-type inner surface broaching tool that finishes a workpiece having a hardness of 45 to 65 HRC, and a plurality of cemented carbide blades are implanted in each of the plurality of grooves, Since it is an assembly type inner surface broach tool in which a buffer member is provided between cemented cemented carbide blades adjacent to each other in the longitudinal direction, the cemented carbide provided continuously in the longitudinal direction in the groove of the broach body Even when a high hardness material of 45 to 65 HRC is broached with an assembly-type inner surface broach tool having a blade, the cemented carbide blade can be machined stably for a long time without chipping or cracking.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1A is a partial cross-sectional side view of an assembly-type inner surface broach tool showing an embodiment of the present invention, FIG. 1B is an enlarged cross-sectional view taken along line AA in FIG. 1A, and FIG. -B line expanded sectional view, (d) is the CC line expanded sectional view of (a), FIG. 2 is a top view of the workpiece | work used in embodiment of this invention. The assembly-type inner surface broach tool 1 shown in FIG. 1A used in the embodiment of the present invention is a broach for finishing the three ball spline grooves 18, 19, and 20 of the workpiece 21 shown in FIG. It is a tool. The workpiece 21 to be processed has a hardness of 62 HRC by carburizing and quenching, and the ball spline grooves 18, 19, and 20 are pre-processed leaving a finishing allowance.

  As shown in FIGS. 1 (a), (b), (c), and (d), the broach body 2 of the assembly type inner surface broach tool 1 of the present invention is manufactured using a high-speed tool steel material, and at both ends thereof. A rear grip 61 and a front grip 60 for pulling out the assembly-type inner surface broach tool 1 are formed. The broach main body 2 here refers to the assembly-type inner surface broach tool 1 before a blade to be described later is implanted. A plurality of grooves 7, 8, 9 extending in the longitudinal direction are formed on the outer circumferential surface of the broach body 2. First cemented carbide blades 10, 11, 12 having cutting edges 4 in the plurality of grooves 7, 8, 9 are respectively implanted and fixed with set bolts 13, 14, 15. Front guides 51 are provided in front of the first cemented carbide blades 10, 11, 12, respectively, and the front guides 51 determine the phase between the work grooves 18, 19, 20 of the workpiece 21 and the cutting edge 4. , I will guide you.

  Buffer members 40, 41, 42 are implanted in the grooves 7, 8, 9 behind the first cemented carbide blades 10, 11, 12, and are fixed by set bolts 43, 44, 45. About this buffer member, as described above, when assembling the assembling-type inner surface broach tool or having a elasticity that does not cause a gap between the buffer member and the adjacent cemented carbide blade during broaching, Examples of this property include alloy steel, aluminum alloy, copper alloy, and resin. In the embodiment of the present invention, the alloy steel having the above-mentioned properties best among them is used for the buffer members 40, 41, and 42.

  Second cemented carbide blades 30, 31, and 32 are respectively implanted behind the buffer members 40, 41, and 42 and fixed by set bolts 33, 34, and 35. The assembly type inner surface broach tool 1 is pulled out in the direction of the front grip 60, and the cutting edges 4 of the first cemented carbide blades 10, 11, 12 and the cutting edges 5 of the second cemented carbide blades 30, 31, 32 and The ball spline grooves 18, 19, and 29 shown in FIG. The above-mentioned buffer members 40, 41, 42 implanted between the first cemented carbide blades 10, 11, 12 and the second cemented carbide blades 30, 31, 32, both of which are made of a brittle material, are described above. Alloy steel with sufficient strength and toughness. Therefore, since the brittle materials are not in direct contact with each other, the blades near the mating surfaces of the first cemented carbide blades 10, 11, 12 and the second cemented carbide blades 30, 31, 32 are broken, It will not be missing.

  In the embodiment of the present invention, the first cemented carbide blades 10, 11, 12 and the second super-hard alloy blades are formed in the plurality of grooves 7, 8, 9 in the longitudinal direction on the outer circumferential surface of the rod-shaped broach body 2. Although the hard alloy blades 30, 31, and 32 are respectively implanted in the longitudinal direction, it is needless to say that the number of grooves is not limited to three and can be appropriately selected depending on the shape of the workpiece.

  In the embodiment of the present invention, the buffer members 40, 41, 42 are provided between the first cemented carbide blades 10, 11, 12 and the second cemented carbide blades 30, 31, 32. However, when three or more blades are continuous in the longitudinal direction of the grooves 7, 8, 9, it goes without saying that a buffer member is provided between each of the continuous cemented carbide blades.

  In the embodiment of the present invention, an example of a ball spline groove broach having three circumferences is shown, but it goes without saying that the present invention can be similarly applied to other shape groove machining broaches such as an involute tooth profile. In the embodiment of the present invention, the buffer members 40, 41, and 42 are independently fixed with the set bolts. However, it is important to fix the buffer members between the cemented carbide blades. The shape of the member and the fixing method are not limited by this embodiment.

  In the embodiment of the present invention, the buffer members 40, 41, 42 are made of alloy steel, but the present invention is not limited to this. That is, as described above, the material used for the buffer members 40, 41, 42 has sufficient strength so that it does not cause brittle fracture when subjected to intermittent impact force by broaching. Any material having toughness may be used. For example, an aluminum alloy, a copper alloy, or a resin may be used.

  Using the assembly-type inner surface broach tool 1 shown in FIGS. 1A, 1B, 1C, and 1D described in the embodiment of the present invention, the workpiece 21 shown in FIG. 2 is cut at a cutting speed of 60 m / min. It was processed with. The workpiece 21 had a hardness of 62 HRC. As a result, even if the number of workpieces exceeds 5000, the first cemented carbide blades 10, 11, 12 and the second cemented carbide blades 30, 31, 32 can be broached without chipping or breaking. Was made.

(A) is the fragmentary sectional side view of the assembly-type inner surface broach tool which shows embodiment of this invention, (b) is the AA line expanded sectional view of (a), (c) is BB of (a). A line expanded sectional view and (d) is a CC line expanded sectional view of (a). It is a top view of the workpiece | work used by embodiment of this invention. It is a partial cross section side view of the assembly-type inner surface broach tool which continuously planted the blade of the conventional example. It is sectional drawing of the assembly-type inner surface broach tool of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Assembling type inner surface broach tool 2 Broach main body 4, 5 Cutting edge 7, 8, 9 Groove 10, 11, 12 1st cemented carbide blade 30,31,32 2nd cemented carbide blade 40,41,42 Buffer Element

Claims (2)

It has a plurality of grooves provided in the longitudinal direction of the outer peripheral surface of the rod-shaped broach body, and a cemented carbide blade having a plurality of cutting edges and detachably attached to the grooves, and has a hardness. An assembly-type inner surface broach tool for finishing a workpiece of 45 to 65 HRC, wherein a plurality of the cemented carbide blades are implanted in each of the plurality of grooves, and the longitudinal length implanted in each groove An assembly type inner surface broaching tool, wherein a buffer member is provided between the cemented carbide blades adjacent to each other in the direction. The assembly type inner surface broaching tool according to claim 1, wherein the buffer member is made of alloy steel.

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