JP2004351582A - Internal finishing broaching tool and internal finishing broaching method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal finishing broaching tool and an internal finishing broaching method which prevent the generation of chipping of a cutting blade, while eliminating a cutter mark. <P>SOLUTION: As a material for a plurality of blade parts 6 arranged in the periphery of the internal finishing broaching tool having a front grip part 2 and a rear grip part 3, a carbide alloy is used, and a clearance part 10 as a deceleration stop range is provided between a back surface 9 of the rearmost blade part and the rear grip part without projecting from the blade part. The cutting blades 5 are provided with unequal pitches in the axial direction. Length of the clearance part is formed twice or more of the length of a workpiece. The internal finishing broaching tool is fitted to a broach lathe 21 by holding the rear grip part, and thereafter, the workpiece 41 to be cut is fixed in front of the front grip part, and finishing machining is performed to the inside surface of the workpiece at machining speed of 40m/min - 80m/min, while holding both the front grip part and the rear grip part. After relatively stopping the workpiece in the clearance part, the rear grip part is released to take the workpiece out of the broach lathe. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to an inner surface finishing broach tool and an inner surface finishing broaching method for a hardened material having a hardness of 45 to 65 HRC after quenching.
[0002]
[Prior art]
Conventionally, when finish broaching a high-hardness work material, for example, in Patent Document 1, the tool material constituting the cutting edge of the broach is made of a cemented carbide, a hard coating is applied, and the rake angle is set to -30 to -30. It is shown that the machining speed should be 40 m / min to 60 m / min at -10 °. FIG. 7 shows an example of machining using such a conventional inner surface finishing broach tool. FIG. 7 shows a broaching machine 21 for moving a work, in which a fixing jig 23 for holding and fixing the front grip 2 is provided on a base 22, and two posts 34, 34 extend upward from both sides thereof. , A work table 25 that can be moved up and down along the post is provided. A lifting jig 26 is provided on the upper stage of the post, and is vertically movable along the posts 24, 24.
[0003]
After holding the rear grip portion 3 of the inner surface finishing broach tool 20 on the broaching machine 21 with the lifting jig 26 and attaching it to the upper portion of the post, the hardness is HRC 45 to 65 on the work table 25 moved forward of the front grip portion 2. The work material 41 having a considerably high hardness is fixed, the rear grip portion 3 is lowered, the front grip portion 2 is passed through the prepared hole of the work material, and the front grip portion is fixed with the fixing jig 23. Is released to allow the lifting jig 26 to wait at the post upper end standby position. Next, the table 25 is moved upward, and the inner surface broaching is performed by the cutting blade 5 provided on the broach 20. The work material 41 which has completed the processing after passing through the cutting blade 5 is taken out from the upper portion of the rear grip portion 3, and the work table 25 is lowered to return to the original position. Further, the lifting jig 26 is lowered to hold the rear grip portion 3, the front grip portion 2 is opened, and the broach 20 is moved upward. Then, the next work material 41 is fixed on the work table 25 in front of the front grip portion 2 again, and the work material is processed in the same manner as described above.
[0004]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2001-239425
[Problems to be solved by the invention]
However, the inner surface finishing broaching of such a high hardness material is usually a final finishing process, which requires higher processing accuracy than a normal broaching process, and has a small cutting allowance. Further, since the cutting edge intermittently cuts into the work material, generation of minute vibration is unavoidable, and the tooth trace accuracy is formed on the processing surface 43 by the cutter mark 39 at the pitch interval of the cutting edge as shown in FIG. There was a problem that remained. Further, there is a problem that such vibration causes chipping of the carbide cutting edge.
[0006]
An object of the present invention is to provide an inner surface finishing broach tool and an inner surface finishing broaching method that do not have a cutter mark and do not cause chipping on a cutting edge in view of such a problem.
[0007]
[Means for Solving the Problems]
In the present invention, the front gripping portion and the rear gripping portion, which are subjected to hole processing while leaving a finishing allowance, and after heat treatment, finish-process a hard material having a hardness of HRC (Rockwell C hardness) 45 to 65 or equivalent. An inner surface finishing broach tool having a blade portion having a plurality of finishing cutting blades arranged in the outer periphery and axial direction of the inner surface finishing broach tool, wherein the material of the blade portion is a cemented carbide, and the rearmost rear surface of the blade portion. And a relief portion having a length not less than twice the length of the work material without protruding from the blade portion and provided between the rear grip portion and the shaft of the cutting blade. The foregoing problems have been solved by providing an internally finished broach tool with unequally spaced directional pitches.
[0008]
That is, as a feature of the broaching of a high-hardness material, the processing speed is remarkably higher at 40 to 60 m / min as compared with a normal broaching speed (10 m / min or less). Further, the cutting resistance is large because the work material is hard, and the rake angle is usually set to an obtuse angle in order to secure the edge strength of the cutting edge, so that the back force increases. For this reason, the vibration generated at the time of the broaching of the hard material is different from the vibration generated at the time of the normal broaching, and the vibration in the direction of the back force, that is, the direction perpendicular to the broaching axis is easily generated at a high frequency. The present inventors have learned this. Based on this knowledge, in the present invention, in order to suppress such vibrations, first, the cutting edges are made to have unequal pitches, and the cycle in which the load is applied is made to be unequal intervals between processings, thereby suppressing the generation of vibrations. Further, as described later, by holding and processing the front grip portion of the broach, and the rear grip portion, the broach rigidity in the direction perpendicular to the broach axis is increased, and the amplitude is suppressed with respect to high-frequency vibration. It is. However, since the rear grip portion is gripped during processing, it is necessary to prevent the work from interfering with the rear grip portion and the lifting jig gripping the rear grip portion after the broaching by the final cutting blade is completed. Therefore, it is necessary to provide a deceleration section from the relative processing speed between the work material and the broach to the stop, and in the present invention, between the rear surface of the rearmost portion of the blade portion and the rear grip portion, the protrusion protrudes from the cutting blade. Without doing so, an escape portion was provided as a deceleration stop section. The length of this relief portion is preferably at least twice the length of the work material from the viewpoints of machining speed, mechanical structure, rigidity and the like (claim 2).
[0009]
By using such an inner surface finishing broaching tool, the cutting speed can be made up to 80 m / min at the maximum by fixing the unequal-pitch cutting blades and the front grip portion and the rear grip portion during broaching. Therefore, in the invention of claim 3, after gripping the rear grip portion of the inner surface finishing broach tool according to claim 1 or 2 and attaching it to the broaching machine, the front grip portion has a hardness equivalent to HRC 45 to 65 in front of the front grip portion. Finishing the inner surface of the work material at a processing speed of 40 m / min to 80 m / min while holding both the front grip portion and the rear grip portion while fixing a high-hardness work material. The above-mentioned problem has been solved by providing an inner surface finishing broaching method in which after the work material is relatively stopped at the portion, the rear grip portion is opened, and the work material is taken out from the broaching machine. .
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an (a) side view of an inner surface finishing broach tool showing an embodiment of the present invention, (b) is a partially enlarged view of a blade portion, and FIG. 2 is an inner surface finishing broach shown in FIG. It is explanatory drawing which shows the state which was turned. As shown in FIG. 1, an inner surface finishing broach tool 1 of the present invention includes a rod-shaped body 4 made of an alloy tool having a front grip 2 at one end and a rear grip 3 at the other end, and a rear grip portion of the rod-shaped body. A cemented carbide assembly 7 provided with a blade 6 having a plurality of finishing blades 5 arranged in a hollow cylindrical shape and a plurality of circumferentially arranged on the outer periphery thereof in the main body is inserted into the guide portion 8 of the main body. It is assembled so that it abuts. The guide portion 8 is provided with a guide protrusion 8a for positioning the broach in the rotational direction by using a prepared hole in the work material as a guide, and is an assembly broach whose phase is matched with that of the guide portion 7a of the assembly 7. The rake angle θ of the cutting blade 5 is an obtuse angle (−10 °), and a hard coating is applied. In particular, in the present invention, the length between the rear surface 9 of the blade portion 6 and the rear grip portion 3 without protruding from the blade portion 6 and at least twice the length of the work material. And the pitch of the cutting blades 5 in the axial direction is made unequal. For example, the pitch of the cutting blades 5a and 5b is a = 7 mm, and the pitch of the cutting blades 5b and 5c is b. = 6 mm, and this is repeated c = 7 mm, d = 6 mm, etc.
[0011]
Using the inner surface finishing broach tool 1, the tooth surface 43 of the involute spline hole 42 formed in the hollow cylindrical work material 41 shown in FIGS. 6A and 6B is carburized and hardened while leaving a finishing allowance. The finish of the tooth surface after making the hardness equivalent to HRC60 was carried out. FIG. 2 shows a work moving type broaching machine 21 similar to that of FIG. 3 described above, in which a fixing jig 23 for holding and fixing the front grip portion 2 is provided on a base 22, and two posts 24, A work table 25 extends upward and is provided to be vertically movable along the post. A lifting jig 26 is provided on the upper stage of the post, and can be moved up and down along the post 24.
[0012]
On the work table 25 in which the rear grip 3 of the inner surface finishing broach tool 1 of the present invention is lifted by the lifting jig 12 and attached to the upper portion of the post 24 on the broaching machine 21, and the front grip 2 is located forward. The work material 41 having high hardness equivalent to HRC 45 to 65 is fixed to the lower surface, the lower grip portion 3 is lowered, the front grip portion 2 is passed through the lower hole of the work material, and the front grip portion 2 is fixed to the fixing jig 23. Fix with. Here, the rear grip portion 3 is held at the same position without being released from the lifting jig 26. Therefore, the upper end of the broach is not restricted in the conventional example, but is restricted by both ends of the front grip part 2 and the rear grip part 3 at the time of processing in the present invention. In this state, the table 25 is moved upward, and the inner surface finishing broaching is performed by the cutting blade 5 provided on the broach 1. The work table 25 is stopped at a position where the work material 41 which has completed the processing after passing through the last cutting edge reaches the escape portion 10, and the processing is completed at a position 25 'indicated by a dotted line. Further, the rear grip portion 3 is lifted and separated from the jig 26, and the lifting jig is made to wait at the post upper end standby position. Thereafter, the work material 41, which has been processed, is taken out from the upper portion of the rear grip portion 3 by further raising the work table 25 ', and the work table 25' is lowered to return to the original position. Further, the lifting jig 26 is lowered to grip the rear grip portion 3, the front grip portion 2 is opened, and the broach tool 1 is moved upward. Then, the next work material 41 is fixed on the work table 25 in front of the front grip portion 2 again, and the work material is processed in the same manner as described above.
[0013]
According to the inner surface finishing broaching method, since the front and rear grip portions 2 and 3 are fixed during broaching, both ends of the inner surface finishing broaching tool 1 are fixed, and the cutting edges 5 are formed at an irregular pitch. Therefore, as shown in FIG. 4, the tooth trace accuracy of the involute spline tooth surface 43 machined by the present invention has no cutter mark 39 like the conventional tooth trace accuracy shown in FIG. There was no good tooth trace accuracy. Further, chipping of the cutting edge, which has conventionally been a problem, has been eliminated.
[0014]
Needless to say, the configuration of the broaching machine is not limited to the above-described embodiment, but includes various examples. For example, as shown in FIG. 4, the present invention can be applied to a broach tool moving type. FIG. 4 shows a lifting jig in which a workpiece 41 is placed on a fixed table 35 and a rear gripping portion 3 which can be moved up and down along posts 34 extending vertically. A broach pulling jig 33 capable of gripping the front grip 2 and the front grip 2 is provided. In this device, the front and rear grip portions 2 and 3 of the inner surface finishing broach tool 1 are respectively fixed by both the broach pulling jig 33 and the lifting jig 36, and as shown in the figure, the two jigs are synchronously pulled down and lowered. The inner surface finish broaching of the work material 41 is performed. In the conventional case, the rear grip 3 is not restrained at the time of lowering, but is restrained in the present invention, so that the same accuracy as the above-described table moving type can be secured. In addition, it automatically separates the rear gripping part from the lifting jig by detecting that the work material has passed through the last cutting edge, and the lifting jig rises at a constant distance at almost the same speed as the work material. However, in the case of the present invention, it is only necessary to relatively stop the work material at the escape portion of the broach, so that it is not necessary to add a new device and a small modification of the conventional broaching machine is performed. Can be realized. Further, the present invention is a finishing broaching process, in which the cutting amount of the cutting blade is small and the entire length is not so long, so that even if the escape portion is provided, the entire broach does not become excessively long.
[0015]
【The invention's effect】
In the present invention, an inner surface finishing broach tool having a front grip portion and a rear grip portion, wherein a material of a blade portion having a finishing cutting blade is made of cemented carbide, and a material of a rearmost rear portion and a rear grip portion of the blade portion. An escape portion having a length of at least twice the length of the work material is provided between them, and furthermore, the pitch in the axial direction of the cutting blade is made unequal, and furthermore, the rear grip portion of this broach is grasped and broached. After mounting on the board, the work material is fixed in front of the front grip portion, and while holding both grip portions, the inner surface of the work material is finished at a processing speed of 40 m / min to 80 m / min, and the work is cut at the escape portion. After stopping the material relatively, the rear grip is released and the work material is taken out from the broaching machine, so vibration during processing is reduced, and cutter marks remain on the processing surface at the cutting edge pitch interval. Things have disappeared. In addition, chipping of the carbide cutting edge is eliminated, and the life of the broach is extended. Further, the processing speed can be used up to a maximum of 80 m / min, and the productivity is improved. Further, the broach tool has a simple structure in which a relief portion is simply added as compared with the conventional broach tool, and has effects such as easy production.
[Brief description of the drawings]
FIG. 1A is a side view and FIG. 1B is an enlarged side view of a hub of an internal finishing broaching tool showing an embodiment of the present invention.
FIG. 2 is an explanatory view showing a state where the inner surface finishing broaching tool of the present invention is mounted on a work movable broaching machine.
FIG. 3 is an explanatory view showing a state in which the inner surface finishing broach tool of the present invention is mounted on a broach movable broaching machine.
FIG. 4 is a schematic view showing a cross-sectional shape of a machined surface when the inner surface finishing broaching tool of the present invention is processed by the inner surface finishing broaching method of the present invention.
FIG. 5 is a schematic view showing a cross-sectional shape of a machined surface when machining with a conventional inner surface finishing broach tool.
FIG. 6A is a plan view and FIG. 6B is a partially enlarged view of a work material.
FIG. 7 is an explanatory view showing a state in which a conventional inner broaching tool is attached to a work movable broaching machine.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inner surface finishing broach tool 2 Front grip part 3 Rear grip part 5 Cutting blade 6 Blade part 9 The back of the last part of blade part 10 Deceleration stop section (relief part)
21, 31 Broaching machine 41 Work material

Claims (3)

An inner surface finishing broach tool having a front grip portion and a rear grip portion for finishing a high hardness work material having a hardness equivalent to 45 to 65 HRC (Rockwell C hardness) after heat treatment and heat treatment. The material of the blade portion having a plurality of finishing cutting blades arranged in the circumference and the axial direction of the outer periphery of the inner surface finishing broach tool is made of cemented carbide, and the rearmost rear surface of the blade portion and the rear grip are formed. A relief portion is provided between the upper and lower portions without protruding from the blade portion and as a deceleration stop section, and the pitch in the axial direction of the cutting blade is irregularly spaced. Internal finishing broach tool. The inner finishing broach tool according to claim 1, wherein the relief portion has a length that is at least twice the length of the work material. After gripping the rear grip portion of the inner surface finishing broach tool according to claim 1 or 2 and attaching it to a broaching machine, a hard material having a hardness equivalent to HRC 45 to 65 is fixed in front of the front grip portion, The inner surface of the work material is finished at a processing speed of 40 m / min to 80 m / min while holding both the front grip portion and the rear grip portion, and the work material is relatively stopped at the relief portion. And after that, the rear grip portion is released, and the work material is taken out from the broaching machine.

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