JP5768969B2 - Broaching tool with protrusion-type front guide - Google Patents

Description

The present invention relates to a broaching tool having a large number of cutting edges in the axial direction of a rod-shaped main body. The present invention relates to a broach tool having a projection-type front guide portion to be fitted.

  Conventionally, for example, broaching tools for machining internal gears have a front gripping portion, a cylindrical front guide portion having a tapered surface, a rough finish cutting edge portion, an intermediate finishing cutting edge portion, a finishing cutting edge portion, a rear guiding portion, and a rear gripping portion. The parts are provided sequentially. The front gripping part is inserted into the pre-working hole of the work piece, the front guide part is fitted into the pre-working hole of the work piece while centering at the taper part, and the work and the broach are centered. Further, by pulling out the broach tool, the pre-processed holes are sequentially cut with a cutting edge to form an internal gear.

  However, in order to correct or remove the heat treatment deformation of the high-hardness material after the heat treatment and the burrs and the like due to the pre-processing such as milling, a finishing process using a broach may be performed. Alternatively, in the case of an internal spline (internal gear) that fits into an external spline (external gear) for preventing gear disengagement during traveling of a power transmission transmission gear device of an automobile, a broach, a pinion cutter, etc. In addition, a finish broach is used which is rolled by a rolling tool (Patent Document 1) which has been coarsely cut in advance and formed with a lead puncher and a plurality of tapered teeth in the direction of the tooth traces on the outer periphery. In such a case, in finishing or deburring broaching, not only centering but also positioning in the rotational direction is required.

  Therefore, in the case of Patent Document 2, the protrusion guide portions that can be fitted into the pre-processed spline grooves of the workpiece are equally arranged in the longitudinal direction on the outer peripheral surface of the cylindrical portion of the front guide portion. Provided with an inclined part that gradually decreases in the width direction and height direction toward the grip part (gradually increases toward the rear) on the tip side of the projection guide part (for example, a quadrangular pyramid is divided into two equal parts in the axial direction and Shape as if attached in the direction), centering and positioning in the circumferential direction, finishing of the hard material.

  Moreover, in the push broach of patent document 3, the guide part which guides the spline hole of a workpiece | work is provided in the both sides of the cutting blade. The front guide portion is provided with an inclined portion on the front end side, and the rear guide portion is provided with inclined portions on both the front end side and the rear end side to perform deburring and burnishing.

  On the other hand, Patent Document 4 has a plastic finishing blade on the rear side of the cutting blade. This plastic finishing blade has no cutting edge and is formed of a front inclined surface, an upper inclined surface, a rear vertical surface, a left and right approach surface, and left and right straight land portions. The workpiece surface is plastically worked by expanding the approach surface and the straight land portion with the tooth thickness surface of the tooth cut by the cutting blade. Then, while the left and right approach surfaces perform circumferential positioning and plastic processing, the front inclined surface and the upper inclined surface are fitted to the tooth bottom portion processed by the front cutting edge to suppress radial movement. .

Utility Model Registration No. 2547999 JP 2004-130484 A JP 2006-334705 A JP 2008-161971 A

  However, the conventional heat treatment strain, pre-processed burr, and rolling strain have large variations in pre-processed tooth errors and tooth surface bulges. For this reason, since the fitting clearance between the groove on the workpiece side and the guide portion is set to be large, there is a problem that the centering and circumferential positioning accuracy are poor. In addition, there is a problem that the work is not inserted straight in the axial direction and machining defects occur. On the other hand, the front inclined surface and the upper inclined surface of Patent Document 4 suppress radial movement during plastic processing in the circumferential direction, and the inclination angle of the front inclined surface exceeds 60 degrees and is nearly vertical, and the centering effect is such Cannot be expected. SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a broach having a protrusion-type front guide portion that can be easily centered and positioned in the circumferential direction even if there are distortions or errors in the machined teeth machined by the pre-machining. Is to provide a tool.

  In the present invention, in the broach tool having a front guide part and a protrusion guide part protruding from the outer peripheral surface of the front guide part and extending in the axial direction, the protrusion guide part has a radial height in the axial direction. A constant outer guide surface, side portions formed on both sides of the outer guide surface, an outer inclined portion provided at a front portion of the outer guide surface for guiding in a radial direction, and a front side of the side portion; And a side surface inclined portion that is provided along a part of the outer guide surface and that is formed along the outer inclined portion for guiding in a circumferential direction, and a side surface connecting line between the side surface inclined portion and the side surface portion. The above-described problem has been solved by providing a broach tool having a protruding front guide portion that is positioned rearward of the position of the outer connection line between the outer guide surface and the outer inclined portion. .

  That is, since the position of the side connection line is positioned behind the position of the outer (radial direction) connection line, first, the outer inclined portion is gradually fitted along the bottom of the work side guide groove. Centering is performed. At this time, positioning has not been completed on the circumferential direction side. Subsequently, the side inclined portion is gradually fitted along the tooth surface of the workpiece side guide groove to perform circumferential positioning. In particular, a portion where distortion is small in the pre-processing, a portion where there is no bulge, or a portion where burrs or the like are small becomes a radial groove bottom. On the other hand, the tooth surface has large errors and variations. Therefore, by performing the centering in the radial direction first, and then performing the positioning in the circumferential direction, the centering and positioning with higher accuracy can be performed.

  A smaller inclination angle of the outer inclined portion with respect to the broach axis is better. However, since the position of the side connection line is behind the position of the outer connection line, if the fitting length is to be ensured, the shift amount of the connection line directly increases the broach length. Accordingly, in the invention described in claim 2, the outer inclined portion is a broach tool having a protruding type front guide portion having a stepped shape of one or two steps.

In the invention according to claim 3, the outer inclined portion or the side inclined portion is a curved surface. Further, in the invention described in claim 4, wherein the broach is internal gear finishing broaching tool and arranged equally the protruding guide portion to the front guide portion of the tubular.

  In the present invention, the position of the side connection line of the broach tool having the projection guide portion is positioned rearward from the position of the outer connection line, and first, the core is formed by the outer inclined portion that fits to the tooth bottom with less error and rising burrs. However, for tooth surfaces that have errors and bulges. Since circumferential positioning is performed at the side inclined part, radial centering is ensured, circumferential positioning accuracy is improved, workpiece tilt is reduced, and high-precision finishing broaching is provided. became.

Further, in the invention according to claim 2, the outer inclined portion has a stepped shape of one or two steps, and the length of the outer inclined portion is shortened, so that the length of the broach is not increased. The same shape can be easily secured. Further, by making the inclined portion a curve instead of a straight line, smooth centering and circumferential positioning can be performed. Furthermore, in the invention described in claim 4, since the projection guide portion can be arranged on the front guide portion equally on the outer periphery, it can be immediately applied to a conventional finishing broach and the accuracy can be improved.

(A) of the protrusion guide part which shows 1st embodiment of this invention is a partial enlarged plan view, (b) is a partial enlarged side view. (A) of the protrusion guide part which shows 2nd embodiment of this invention is a partial enlarged plan view, (b) is a partial enlarged side view. (A) of the protrusion guide part which shows 3rd embodiment of this invention is a partial enlarged plan view, (b) is a partial enlarged side view. It is the side view which notched some broach tools which have a projection guide part of this invention.

  Embodiments of the present invention will be described with reference to the drawings. The case where it applies to the cemented carbide broach tool for the finishing of the high hardness material of patent document 2 mentioned above is described. As shown in FIG. 4, the broaching tool 1 includes a rod-like main body 3 made of alloy steel having a front grip portion 2 provided at the tip thereof, a cylindrical cutting blade body 5 with a cutting edge 4, and a projection guide portion. A hollow front guide portion 7 having no cutting edge provided with 6 is sequentially inserted, and is sandwiched and fixed between the front end surface 8a of the rear grip portion 8 of the rod-shaped body and the double nuts 9 and 9. Insert the front grip 2 into the workpiece hole and pull it out to finish the inner surface of the workpiece.

The front guide portion 7 includes a cylindrical portion 10 having an outer diameter slightly smaller than the minimum inner diameter of the workpiece and a front inclined (tapered) portion 11 having a structure that is reduced in diameter toward the front grip portion 2. On the outer peripheral surface of the cylindrical portion 10, projection guide portions 6 that can be fitted in the spline grooves of the workpiece are provided equally in the longitudinal direction. The cutting blade body 5 is provided with a main body side guide portion 12 for centering in the same phase as the projection guide portion 6 and a number of cutting blades 4 whose blade length gradually increases toward the rear.

In the first embodiment of the present invention, as shown in FIG. 1, the protrusion guide portion 6 includes an outer guide surface 20 whose height extending in the cutting edge direction is constant in the axial direction, and both sides of the outer guide surface. Each side surface portion 21 is provided. The outer guide surface draws a circle in the circumferential direction (the root diameter of the workpiece). Further, an outer inclined portion 23 connected to the outer peripheral surface 22 and gradually increasing in the cutting edge direction is provided at the front portion of the outer guide surface 20. Further, a side inclined portion 24 connected to the outer peripheral surface 22 and formed along the outer inclined portion 23 and having a side width gradually increasing in the cutting edge direction is provided at the front portion of the side portion 21.

  The position of the connecting line 25 between the side inclined part 24 and the side part 21 is positioned in the direction of the cutting blade body 5 (rearward) from the position of the connecting line 26 between the outer guide surface 20 and the outer inclined part 23. . The inclination angle of the outer inclined portion is 45 degrees or less, preferably 30 degrees or less with respect to the broach axis direction.

  In the projection guide portion 6, first, approximately centering is performed along the tapered portion 11. Next, the workpiece tooth groove bottom and the outer inclined portion 23 are gradually fitted, and radial centering is performed along the outer inclined portion. At the same time, the workpiece groove tooth surface and the side inclined portion 24 are gradually fitted in the radial direction, and positioning is gradually performed in the circumferential direction along the side inclined portion. However, since the position of the connection line 25 is located behind the position of the connection line 26, the circumferential positioning is not completed until the centering operation is completed.

  In other words, the tooth groove bottom side of the work is less strained or less raised in the pre-processing, and has less burrs and the like. The outer inclined portion 23 gradually increases in the radial direction along the bottom of the tooth groove and fits with the outer guide surface 20. Thereby, a highly accurate centering is performed. Since the centering can be performed firmly, the positioning of the tooth surface in the circumferential direction with many errors and the like is further guided by the side inclined portion 24 after the centering is performed, and the positioning is performed by the side surface portion 21. For this reason, positioning with high accuracy was made possible.

  In addition, although the outer diameter of the outer peripheral surface 22 of the cylindrical part 10 is fitted to the inner diameter (valley diameter, tooth tip circle diameter) of the workpiece, if the accuracy of the inner diameter of the workpiece is poor, a sufficient gap is given. However, since the centering with small errors and variations is performed between the workpiece tooth groove bottom and the outer guide surface, it is less affected by such a gap, so that the centering and positioning can be performed with high accuracy.

  A second embodiment of the present invention will be described. FIG. 2 is a perspective view of the protrusion guide portion 61 showing the second embodiment. The outer inclined portion is different from that of the first embodiment. The same parts as those in the first embodiment described above are denoted by the same reference numerals and a part of the description is omitted. In the present embodiment, the outer inclined portion 33 has two stages. The inclination angle of the outer inclined portion 34 on the outer guide surface 20 side, which is important for centering, is made gentle, and the inclination angle of the distal end side 35 of the outer inclined portion that does not require accuracy is increased. Thereby, the position of the connection line 25 in the circumferential direction can be made the same as the conventional one, and the entire length of the broach can be limited.

  A third embodiment of the present invention will be described. FIG. 3 is a perspective view of the protrusion guide portion 62 showing the third embodiment. In the second embodiment, the outer inclined portion 43 has an outwardly convex curve. In addition, about the same part as 1st, 2nd embodiment mentioned above, the same code | symbol is attached | subjected and a part of description is abbreviate | omitted. In the present embodiment, the outer inclined portion 43 is formed as a convex curve outward. The rising inclination angle is maximized, and the inclination angle gradually decreases as the outer guide surface 20 is approached. 2 and 3, the final inclination angle of the outer inclined portions 33 and 43 is set to about 15 degrees so that the connection line is clear, but the final inclination angle may be set to 0 degree. The average inclination angle is 45 degrees or less, preferably 30 degrees or less.

  In the above description, the example applied to the broaching tool of the high-hardness material after the heat treatment has been described. However, it can be appropriately applied to a push broach or a general broaching tool. Moreover, although the protrusion guide part is provided equally, it may be provided in one place, more places, or unequal. Moreover, although it is circular in the radial direction cross section of an outer side guide surface or an outer side inclined surface, a straight line etc. may be sufficient. Furthermore, it goes without saying that the length of the protrusion guide portion is also set as appropriate.

DESCRIPTION OF SYMBOLS 1 Broach tool 6, 61, 62 Protrusion guide part 7 Front guide part 20 Outer guide surface 21 Side part 22 Outer peripheral surface 23, 33, 43 Outer inclined part 24 Side inclined part 25 Side connection line 26 Outer connection line

Claims (4)

  A broaching tool having a front guide part and a protrusion guide part protruding from the outer peripheral surface of the front guide part and extending in the axial direction, wherein the protrusion guide part is an outer side whose radial height is constant in the axial direction. A guide surface, side portions respectively formed on both sides of the outer guide surface, an outer inclined portion provided at a front portion of the outer guide surface for guiding in a radial direction, and provided at a front portion of the side portion; A part of the outer guide surface and a side inclined part formed along the outer inclined part for guiding in the circumferential direction, and the position of the side connection line between the side inclined part and the side part is A broaching tool having a protruding front guide portion, characterized in that it is positioned rearward from the position of the outer connection line between the outer guide surface and the outer inclined portion.   The broaching tool having a protrusion-type front guide portion according to claim 1, wherein the outer inclined portion has a stepped shape of one step or two steps.   The broaching tool having a protruding front guide portion according to claim 1, wherein the outer inclined portion or the side inclined portion is a curved surface. 4. The broach having a projection type front guide portion according to claim 1, wherein the broach is an internal gear finishing broach tool, and the projection guide portion is arranged on the cylindrical front guide portion at an equal outer periphery. tool.

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