JP2021074845A - Jig for broaching - Google Patents

Abstract

To provide a jig for broaching that can perform broaching to a work-piece using a cylindrical shell as a single body.SOLUTION: The jig for broaching comprises a jig main body 1 in a multistage columnar shape with an axis line O as a center. A shaft part 4 extending to a rear end side of the jig main body 1 is inserted into an inner periphery part of a cylindrical shell 5 so that the shell 5 is detachably attached to the jig main body 1. A plurality of cutting blade rows 7, in which a plurality of cutting blades are protruded toward an outer periphery in a radial direction with respect to the axis line O and are arranged in a spiral shape in which the blades are twisted around the axis line O as going from a tip side of the jig main body 1 toward the rear end thereof, are arranged at an outer periphery part of the shell 5, with intervals in a circumferential direction of the shell 5. An outer periphery part at a tip of the jig main body 1 is provided with a main body guiding blade 11 which is matched in phase with a spire formed by the cutting blade rows 7, where a blade width of a rear end part of the main body guiding blade 11 is larger than a blade width of the cutting blade at the forefront of the cutting blade rows 7.SELECTED DRAWING: Figure 1

Description

The present invention includes a jig body having a multi-stage columnar shape centered on an axis, and a shaft portion extending toward the rear end side of the jig body is inserted into the inner peripheral portion of the cylindrical shell of the helical broach. The present invention relates to a broaching jig in which the shell is detachably attached to the jig body.

In Patent Document 1, as a broach for machining internal gears, a plurality of rough cutting blades and a plurality of alternating round blades following the plurality of rough cutting blades are provided from the front end side to the rear end side of the broach body. The finishing cutting blade, which consists of the finishing shell blade following the plurality of alternating round blades and finishes the tooth groove of the internal gear, is detachably attached to the rear end of the broach body by a lock nut. A prefabricated broach formed in a cylindrical shell is described.

Japanese Unexamined Patent Publication No. 2008-22418

By the way, in the cutting process of the internal tooth gear by such a broach, the inner peripheral portion of the annular workpiece is usually formed by a broach provided with a rough cutting blade portion and a finishing cutting blade portion as described in Patent Document 1. Rough cutting that begins to form a tooth groove and finish cutting that finishes the tooth surface of the tooth groove to a predetermined size and shape are performed at once, but rough cutting and finish cutting may be required to be performed in separate processes. ..

For example, when broaching a heat-treated workpiece, if one broach is used to perform rough cutting and finish cutting at the same time, the work that has become hard due to the heat treatment is roughly cut with a large allowance. The wear of the cutting blade becomes large and the life is shortened. However, when rough cutting is performed on a workpiece with low hardness before heat treatment and then heat treatment is performed, and then finish cutting is performed, the rough cutting blade is used. It is possible to suppress the wear of the portion.

However, although rough cutting can be performed by the brooch body with only the rough cutting blade part from which the shell is removed, the tooth groove is roughly cut by a single cylindrical shell having a finish cutting blade part formed on the outer peripheral part. It is difficult to perform only finish cutting by inserting it into the inner peripheral portion of the annular work that has been heat-treated at the same time.

The present invention has been made under such a background, and an object of the present invention is to provide a broaching jig capable of broaching a work by using a cylindrical shell alone.

In order to solve the above problems and achieve such an object, the present invention includes a jig body having a multi-stage columnar shape centered on an axis, and a shaft portion extending toward the rear end side of the jig body. However, the shell is detachably attached to the jig body by being inserted into the inner peripheral portion of the cylindrical shell of the helical broach, and a plurality of cutting edges are attached to the outer peripheral portion of the shell with respect to the axis. A plurality of rows of cutting edges, which are arranged in a spiral shape that protrudes to the outer peripheral side in the radial direction and twists around the axis from the front end side to the rear end side of the jig body, are spaced apart from each other in the circumferential direction of the shell. A main body guide blade that is arranged in phase with the spiral formed by the cutting edge row is provided on the outer peripheral portion of the tip of the jig main body, and the blade width of the rear end portion of the main body guide blade is It is characterized in that it is larger than the blade width of the tip of the cutting edge, which is the most advanced of the cutting edge row.

In the broaching jig configured in this way, the shaft portion extending toward the rear end side of the jig body forming a multi-stage columnar shape centered on the axis is inserted into the inner peripheral portion of the cylindrical shell of the helical broach. Therefore, the shell can be detachably attached to the jig body by pressing the shell with a lock nut or the like attached to the shaft portion. Therefore, by forming the front grip portion, the rear grip portion, and the like on the jig main body, it is possible to perform finish cutting with the shell of the assembly type helical brooch alone.

A main body guide blade that is in phase with the spiral formed by the cutting edge row on the outer peripheral portion of the shell is provided on the outer peripheral portion of the tip of the jig main body, and the blade width of the rear end portion of this main body guide blade is Since it is larger than the blade width of the tip of the most advanced cutting edge of the cutting edge row, this main body guide can be obtained by inserting the main body guide blade into the tooth groove formed in advance by rough cutting in the inner peripheral portion of the annular workpiece. It is possible to reliably and smoothly insert the cutting edge row on the outer periphery of the shell from the blade into the tooth groove.

Further, the shell guide in which the cutting edge of the cutting edge of the cutting edge row in the shell has a chamfered portion formed at an intersecting ridge line portion between the tip surface of the cutting blade and the side surface facing both sides in the circumferential direction of the jig body. In the case of a blade, the blade width of the rear end of the main body guide blade is made larger than the blade width of the tip of the shell guide blade, and is larger than the blade width of the rear end of the shell guide blade. By making the size smaller, the tooth groove can be more smoothly passed from the main body guide blade to the shell guide blade, and the work can be positioned in the circumferential direction at the rear end portion of the shell guide blade.

By the way, when the tooth groove is roughly cut and the annular work that has been heat-treated is subjected to finish cutting as described above, the work is subjected to thermal strain due to the heat of the heat treatment, and the work is rough. The tooth grooves of the machined work may be deformed so that both tooth surfaces facing each other are raised. If the finishing cutting blade is guided to the tooth surface that is deformed and raised in this way and the facing tooth surface is finished and cut, the machining accuracy of the machined internal gear may be impaired.

Therefore, in such a case, the shell guide blades inserted into the tooth grooves formed in the work in this order toward the rear end side of the jig body and the tooth grooves are mutually formed on the outer peripheral portion of the shell. By forming a strain removing blade that cuts both tooth surfaces facing each other at the same time, and a finish cutting blade consisting of a sharp-angle cutting blade and an blunt-angle cutting blade that finish-cuts both tooth surfaces, the tooth groove of the workpiece is subjected to thermal strain due to heat treatment. Even if both tooth surfaces are raised, both tooth surfaces of the tooth groove to be finish-cut by the finish cutting blade can be arranged at a predetermined position by the strain removing blade, whereby the teeth can be processed with high processing accuracy. It becomes possible to form a groove.

The tip of the main body guide blade is also formed with a chamfered portion at the intersection ridge between the tip surface of the main body guide blade and the side surface facing both sides in the circumferential direction of the jig main body. It can be smoothly inserted into the tooth groove formed on the inner peripheral portion of the work, and the processing efficiency can be improved.

As described above, according to the present invention, it is possible to perform finish cutting of a workpiece having a groove formed in the inner peripheral portion by rough cutting in advance with the shell of the assembly type helical brooch alone, and to guide the main body. The cutting edge row on the outer periphery of the shell can be reliably and smoothly inserted into the tooth groove from the blade, and efficient broaching can be performed.

It is a side view which shows the state which the shell is attached to the jig body in one Embodiment of this invention. It is a side view of the jig body alone in the embodiment shown in FIG. It is an enlarged view of the part A in FIG. FIG. 5 is a schematic view showing a cutting edge (guide blade, strain removing blade, finishing cutting blade) on the tip end side of the finishing cutting cutting edge portion of the shell according to the embodiment shown in FIG.

1 to 3 show an embodiment of the present invention. In the present embodiment, the jig body 1 is formed of a metal material such as a steel material into a multi-stage columnar shape centered on the axis O, and the tip portion of the jig body 1 (lower portion in FIGS. 1 and 2). ) Is formed with a front grip portion 2, and the rear end side (upper side in FIGS. 1 and 2) of the front grip portion 2 is expanded in a truncated cone shape toward the rear end side and then substantially cylindrical. A main body guide portion 3 is formed, and a columnar shaft portion 4 having a diameter smaller than that of the main body guide portion 3 is formed on the rear end side of the main body guide portion 3 so as to extend toward the rear end side. There is.

A shell 5 of an assembly type helical brooch is attached to the shaft portion 4. The shell 5 is formed in a cylindrical shape centered on the axis O by a metal material having a hardness higher than that of the jig body 1 such as high-speed tool steel, and the shaft portion 4 is fitted in the inner peripheral portion to form a key and a key (not shown). It can be attached to and detached from the jig body 1 by being pressed against the tip side by the locknut 6 in a state where the tip surface is in contact with the rear end surface of the main body guide portion 3 while being prevented from rotating in the circumferential direction by a key groove or the like. It is attached.

On the outer peripheral portion of the shell 5, a plurality of (many) cutting edges protruding toward the outer peripheral side in the radial direction are arranged at intervals in the axial direction O direction (longitudinal direction) and the circumferential direction of the jig main body 1. These cutting edges are arranged at equal intervals in the circumferential direction of the jig body 1 in accordance with the spacing of the tooth grooves G formed in advance on the inner circumference of the work W by rough cutting, and are arranged in the axial direction O direction. Is formed so as to form a cutting edge row 7 arranged at intervals along a lead (string winding) L twisted around the axis O corresponding to the spiral formed by the tooth groove G.

Further, in the present embodiment, the cutting edge row 7 is inserted into the tooth groove G formed in the work W by rough cutting in order from the front end side of the shell 5 toward the rear end side as shown in FIG. Sharp angle cutting that finish-cuts the shell guide blade 8, the strain removing blade 9 that simultaneously cuts both tooth surfaces F1 and F2 facing each other in the tooth groove G, and the both tooth surfaces F1 and F2 thus cut by the strain removing blade 9. It is provided with a finishing cutting blade 10 including a blade and an oblique cutting blade.

The shell guide blade 8 has a blade width Z in the direction perpendicular to the lead L at the rear end having a size that can be inserted into the tooth groove G formed by rough cutting as shown in FIG. A chamfered portion 8A is formed at the intersecting ridgeline portion between the end surface facing the tip side of 8 and the two side surfaces facing both sides in the circumferential direction, and guides the shell 5 and the jig body 1 relative to the work W. It just doesn't cut.

Further, the strain removing blade 9 is formed with cutting blades 9C at the intersecting ridges of the end surface (rake surface 9A) facing the tip end side of the jig body 1 and the two side surfaces (relief surface 9B) facing both sides in the circumferential direction. The two flanks 9B are provided with flank angles for both tooth surfaces F1 and F2 of the tooth groove G, respectively. Although only one strain removing blade 9 is shown in FIG. 4, when the allowance for the tooth groove G of the strain removing blade 9 described below is large, the blade is directed toward the rear end side of the shell 5. A plurality of strain removing blades 9 whose width gradually increases may be arranged along the lead L.

Further, the blade width of the strain removing blade 9 between these cutting blades 9C is slightly larger than the width of the tooth groove G. The difference between the blade width of the cutting blade 9C and the groove width of the tooth groove G, that is, the allowance for the strain removing blade 9 with respect to the tooth groove G is in the range of 10 μm to 100 μm in the present embodiment, and there are two. The allowance for each cutting edge 9C for each of the tooth surfaces F1 and F2 is within the range of 5 μm to 50 μm.

Furthermore, in the finish cutting blade 10, as shown in FIG. 4, the cutting blade is formed at the intersecting ridge line portion between the rake face 10A facing the tip side of the shell 5 and one side surface 10B of the two side surfaces 10B facing the circumferential direction. 10C is formed, and a guide blade 10D is formed at the intersecting ridgeline portion between the rake face 10A and the other side surface 10B. The guide blades 10D are arranged along the reed L in which the cutting edge rows 7 are arranged.

Note that FIG. 4 shows only the state-of-the-art finish cutting blade 10 of the shell 5, and the state-of-the-art finish cutting blade 10 is on the sharp angle side of the two tooth surfaces F1 and F2 of the tooth groove G. It is a sharp cutting blade that cuts the tooth surface F1, and the guide blade 10D of this sharp cutting blade is in sliding contact with the tooth surface F2 on the blunt angle side to guide the finishing cutting blade 10. Further, on the rear end side of this cutting-edge sharp-angle cutting blade, the guide blade 10D is located on the lead L where the guide blade 10D of the cutting-edge sharp-angle cutting blade is located, and a plurality of acute angles whose blade width gradually increases. A cutting blade is arranged.

Further, on the rear end side of these plurality of sharp-angle cutting blades, the guide blade 10D is located on the lead L on which the cutting edge 10C of the rearmost sharp-angle cutting blade is located, and a plurality of blunt-angle cuttings in which the blade width is gradually increased. The blades are arranged, and these plurality of blunt-angle cutting blades slide into the tooth surface F1 on the sharp-angle side where the guide blade 10D is finish-cut to guide the finish-cutting blade 10, and finish-cut the tooth surface F2 on the blunt-angle side. To do. A round blade for cutting the top of the tooth profile formed on the work may be provided in the cutting edge row 7 or on the rear end side of the cutting edge row 7.

On the other hand, on the outer circumference of the columnar portion in the main body guide portion 3 on the tip side of the shell 5 of the jig main body 1, the phase is matched with the spiral formed by the cutting edge row 7 of the shell 5 and the lead L of the cutting blade row 7 is formed. The main body guide blade 11 is provided spirally along the line. The blade width X in the direction perpendicular to the lead L at the rear end of the main body guide blade 11 is constant, and as shown in FIG. 3, the most advanced cutting blade of the cutting blade row 7, that is, the shell guide blade 8 It is made larger than the blade width Y in the direction perpendicular to the lead L between the chamfered portions 8A at the tip portion of the blade.

Further, the blade width X at the rear end of the main body guide blade 11 is smaller than the blade width Z at the rear end of the shell guide blade 8. Although not shown, the tip of the main body guide blade 11 has an intersecting ridge line between the tip surface of the main body guide blade 11 and the two side surfaces of the jig main body 1 facing both sides in the circumferential direction, similarly to the shell guide blade 8. A chamfered portion is formed in the portion.

In the broaching jig configured in this way, the rear end side of the jig body 1 with respect to the main body guide portion 3 has the same configuration as the assembly type helical broach, although there is no rear grip portion. By using the shell 5 used for the helical broach as a single unit, it is possible to perform finish cutting of the work W which has been roughly cut in advance.

Therefore, by performing the finish cutting of the work W that has been heat-treated after the rough cutting, it is possible to suppress the wear of the rough cutting blade of the helical brooch that performs the rough cutting. Further, if the number of cutting edge rows 7 of the shells 5 to be attached, the pitch in the circumferential direction, the lead L, and the like are the same, a plurality of types of shells 5 having different numbers and sizes of cutting edges can be combined into one jig body 1. Since it can be attached, for example, one jig body 1 can be used for finish cutting work W having different tooth thicknesses.

Further, in the broaching jig having the above configuration, the main body guide blade 11 having the same phase as the spiral formed by the cutting edge row 7 on the outer peripheral portion of the shell 5 is provided on the outer periphery of the main body guide portion 3 at the tip of the jig main body 1. Since the blade width X at the rear end of the main body guide blade 11 is larger than the blade width Y at the tip of the most advanced cutting blade (shell guide blade 8) of the cutting edge row 7, the work W is provided. By inserting and guiding the main body guide blade 11 into the tooth groove G, the cutting edge row 7 of the shell 5 is reliably and smoothly formed into the tooth groove G from the main body guide blade 11 via the narrow shell guide blade 8. It can be inserted and efficient finish cutting can be performed.

In particular, in the present embodiment, the most advanced cutting edge of the cutting edge row 7 of the shell 5 has a chamfered portion 8A formed at the intersecting ridge line portion between the tip end surface of the cutting edge and the side surface facing both sides in the circumferential direction of the shell 5. The shell guide blade 8 has a tapered shape, and the blade width X at the rear end of the main body guide blade 11 is made larger than the blade width Y at the tip of the shell guide blade 8 as described above. At the same time, it is made smaller than the blade width Z at the rear end of the shell guide blade 8.

Therefore, the shell guide blade 8 can be more smoothly inserted into the tooth groove G by guiding by the chamfered portion 8A, and the work W is circumferentially driven by the rear end portion of the shell guide blade 8 having the largest blade width Z. Since it can be positioned at, it is possible to perform high-precision finish cutting.

Further, when the work W that has been heat-treated after the tooth groove G is roughly cut as described above is subjected to finish cutting, thermal strain is generated in the work W and both tooth surfaces of the tooth groove G facing each other are generated. If F1 and F2 are deformed so as to swell, and the guide blade 10D of the finish cutting blade 10 is guided to the deformed tooth surfaces F1 and F2 to perform finish cutting, the machining accuracy of the machined work W may be impaired. There is.

On the other hand, in the present embodiment, the work is provided with a strain removing blade 9 for simultaneously cutting both tooth surfaces F1 and F2 of the tooth grooves G facing each other on the tip end side of the cutting edge row 7 of the shell 5. Even if both tooth surfaces F1 and F2 of the tooth groove G of W are deformed, both tooth surfaces F1 and F2 to be finish-cut by the finish cutting blade 10 can be arranged at predetermined positions, whereby high processing can be performed. It is possible to form the tooth groove G with accuracy.

In the present embodiment, the work W in which the tooth groove G is formed in advance by rough cutting is heat-treated, and both tooth surfaces F1 and F2 of the tooth groove G deformed by the thermal strain due to the heat treatment are predetermined. A strain removing blade 9 is provided in order to dispose of the strain removing blade 9 at the position of the above, but when the work W not subjected to such heat treatment is broached, such a strain removing blade 9 is not provided. The finishing cutting blade 10 may be continuous on the rear end side of the shell guide blade 8.

Further, in the present embodiment, as described above, a chamfered portion is also formed at the tip end portion of the main body guide blade 11 at the intersecting ridge line portion between the tip end surface of the main body guide blade 11 and the side surface facing both sides in the circumferential direction of the jig main body 1. The tip of the main body guide blade 11 is also tapered. Therefore, the main body guide blade 11 can be smoothly inserted into the tooth groove G of the work W, so that the processing efficiency can be improved.

1 Jig body 3 Main body guide 4 Shaft 5 Shell 6 Lock nut 7 Cutting edge row 8 Shell guide blade 9 Strain removal blade 10 Finishing cutting blade 11 Main body guide blade O Axis of jig body 1 W work G Tooth groove F1, F2 Tooth surface X Blade width at the rear end of the main body guide blade 11 Y Blade width at the tip of the shell guide blade 8 Z Blade width at the rear end of the shell guide blade 8

Claims (4)

A jig body having a multi-stage columnar shape centered on an axis is provided, and a shaft portion extending toward the rear end side of the jig body is inserted into the inner peripheral portion of the cylindrical shell of the helical broach to form the shell. Is detachably attached to the above jig body,
On the outer peripheral portion of the shell, a plurality of cutting blades are arranged in a spiral shape in which a plurality of cutting blades project toward the outer peripheral side in the radial direction with respect to the axis line and twist around the axis line from the front end side to the rear end side of the jig body. Multiple rows of blades are arranged at intervals in the circumferential direction of the shell.
A main body guide blade that is in phase with the spiral formed by the cutting edge row is provided on the outer peripheral portion of the tip of the jig main body.
A jig for broaching, wherein the blade width of the rear end of the main body guide blade is larger than the blade width of the tip of the cutting edge at the cutting edge of the cutting edge row. The cutting edge at the cutting edge of the cutting edge row in the shell is a shell guide blade having a chamfered portion formed at an intersecting ridge line portion between the tip surface of the cutting blade and the side surfaces facing both sides in the circumferential direction of the jig body. Has been
The blade width of the rear end of the main body guide blade is larger than the blade width of the tip of the shell guide blade and smaller than the blade width of the rear end of the shell guide blade. The broaching jig according to claim 1. On the outer peripheral portion of the shell, a shell guide blade inserted into a tooth groove formed in the work and both tooth surfaces facing each other of the tooth groove are simultaneously cut toward the rear end side of the jig body. The broaching process according to claim 1 or 2, wherein the strain removing blade is formed, and a finish cutting blade including a sharp-angle cutting blade and an blunt-angle cutting blade for finish-cutting both tooth surfaces is formed. jig. 1. The tip of the main body guide blade is characterized in that a chamfered portion is formed at an intersecting ridge line portion between the tip surface of the main body guide blade and the side surfaces facing both sides in the circumferential direction of the jig main body. The jig for broaching according to any one of claims 3.

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