JP2002337022A - Broach guide jig for keyway processing - Google Patents

Abstract

(57) [Problem] To provide a broach guide jig for processing a key groove, which can prevent displacement when forming a key groove. SOLUTION: This is a key groove machining broach guide jig 1 for forming a key groove extending in the length direction of the work W on an inner peripheral surface of a cylindrical hole W1 of the work W. On the outer peripheral surface of the broach guide jig 1, one broach guide groove 2 extending in the longitudinal direction thereof, and also a cylindrical hole extending in the longitudinal direction and forming a key groove.
Two contact portions 6 and 7 that contact the inner peripheral surface of W1 are formed at equal angular intervals in the circumferential direction. A positioning key insertion groove 3 extending in the length direction is formed at a position 180 degrees in the circumferential direction from the broach guide groove 2 on the outer peripheral surface of the broach guide jig 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a broach guide jig for forming a key groove for forming a key groove extending in the longitudinal direction of the work in a cylindrical hole of a work made of, for example, a gear.

[0002]

2. Description of the Related Art When a plurality of, for example, two keyways extending in the longitudinal direction of a work are formed on the inner peripheral surface of a cylindrical hole of the work at intervals of 180 degrees in the circumferential direction, conventionally, as shown in FIG. A broach guide jig is used. The broach guide jig (20) is cylindrical and has a broach guide groove (21) and a positioning key insertion groove (2
2) are formed at 180 degree intervals in the circumferential direction.

[0003] The formation of a keyway using such a broach guide jig (20) is performed as follows. First, the broach guide jig (20) is inserted into the cylindrical hole (W1) of the work (W) (see FIG. 4). ) To form a first key groove (23) by moving the key groove in the length direction (see FIGS. 5 (a) and 5 (b)). Next, the work (W) is rotated by 180 degrees with respect to the broach guide jig (20), and the positioning key (K1) is inserted across the positioning key insertion groove (22) and the first key groove (23). Thereafter, the broach (B) is guided in the broach guide groove (21) and is moved in the length direction relative to the work (W), so that the second key groove (25)
(See FIGS. 5 (c) and 5 (d)). Thus, two keyways (23) and (25) are formed.

[0004]

However, when key grooves (23) and (25) are formed on the inner peripheral surface of a cylindrical hole (W1) of a work (W) using a conventional broach guide jig (20). Keyway
(23) In order to improve the accuracy of the shape, dimensions and position of (25), strictly control the inner diameter of the cylindrical hole (W1) of the work (W) and the outer diameter of the broach guide jig (20). Need to be
Inner peripheral surface of cylindrical hole (W1) of work (W) and broach guide jig (20)
It is inevitable that there is a clearance of about 0.05 mm between the outer peripheral surface and the outer peripheral surface.

[0005] When such a clearance exists, the broach guide jig is formed when the key groove is formed by the broach (B).
(20) is to contact the inner peripheral surface of the cylindrical hole (W1) of the work (W) at both side edges of the opening of the positioning key insertion groove (22) which is circumferentially separated from the broach guide groove (21) by 180 degrees. (See FIG. 4). Therefore, at the time of cutting with the broach (B), the force acting on the broach guide jig (20) causes the broach guide jig (20) to shift to one of the left and right in FIG. 4, and the broach guide jig (20) moves the work (W). Eccentric with respect to the cylindrical hole (W1). As a result, the key grooves (23) and (25) cannot be formed at accurate positions.For example, a straight line (LX) passing through the center of the width of the formed key grooves (23) and (25) is (W) deviates from the diameter passing through the center (O) of the cylindrical hole (W1).

Further, two keyways are formed on the inner peripheral surface of the cylindrical hole (W1) of the work (W) by using a conventional broach guide jig (20).
(23) When (25) is formed, the straight line passing through the width center of both keyways (23) and (25) is the center (O) of the cylindrical hole (W1) of the work (W), respectively.
When it deviates from the diameter passing through, the shaft (S) is inserted into the cylindrical hole (W1) of the work (W), and the two keyways (S1) formed on the shaft (S)
(S2) and cylindrical hole (W1) of workpiece (W) Keyway on inner peripheral surface (23) (25)
When the key (K) is inserted across the center of the axis (S)
(OS) deviates from the center (O) of the cylindrical hole (W1), and as a result, the shaft (S) and the work (W) are eccentric (see FIG. 6). Moreover, the keyway
(23) When the deviation from the diameter passing through the center (O) of the cylindrical hole (W1) of (25) is large, the key (K) may not be able to be inserted.

In FIGS. 4 to 6, the gap between the broach guide jig and the shaft and the cylindrical hole of the work is exaggerated for easy understanding. Not as big. .

An object of the present invention is to provide a broach guide jig for processing a key groove, which can solve the above-mentioned problem and can prevent a shift when forming a key groove.

[0009]

According to the present invention, there is provided a broach guide jig for processing a key groove, wherein a key groove for forming a key groove extending in the longitudinal direction of the work is formed on an inner peripheral surface of a cylindrical hole of the work. A broaching guide jig for groove processing, wherein one broaching guide groove extending in the longitudinal direction is provided on an outer peripheral surface;
Similarly, two contact portions which extend in the length direction and come into contact with the inner peripheral surface of the cylindrical hole when forming the key groove are formed at equal angular intervals in the circumferential direction.

According to the broach guide jig for processing a key groove of the present invention, the broach guide jig is inserted into the cylindrical hole of the work, and in this state, the broach is guided in the broach guide groove, and the broach is guided in the length direction relative to the work. The keyway is formed by cutting the inner peripheral surface of the cylindrical hole of the work with the broach. At this time, the two contact portions contact the inner peripheral surface of the cylindrical hole of the work. Since the broach guide groove and the two contact portions are formed at equal angular intervals in the circumferential direction, displacement of the broach guide jig due to the force acting on the broach guide jig during cutting by the broach is prevented. Therefore, a straight line passing through the center of the width of the formed keyway is located on a diameter passing through the center of the cylindrical hole of the work in the cross section.
As a result, when the shaft is inserted into the cylindrical hole of the work in which the keyway is formed, and the key is inserted across the keyway of the work and the keyway of the shaft, the center of the shaft matches the center of the cylindrical hole, Eccentricity between the shaft and the work is prevented.

In the broach guide jig for processing a key groove according to the present invention, a positioning key insertion groove extending in the longitudinal direction may be formed at a position on the outer peripheral surface that is 180 degrees in the circumferential direction from the broach guide groove. .

In the circumferential direction on the inner peripheral surface of the cylindrical hole of the work, 1
When two key grooves are formed at a position separated by 80 degrees, after forming one key groove as described above, the broach guide jig is rotated 180 degrees with respect to the work, and the positioning key insertion groove is formed first. The positioning key is inserted across the formed keyway. Thereafter, the second key groove is formed by guiding the broach in the broach guide groove and moving the broach relatively to the work in the length direction. Again,
A straight line passing through the center of the width of the second keyway is located on a diameter passing through the center of the cylindrical hole of the work in the cross section. Therefore, when the shaft is inserted into the cylindrical hole of the work in which two key grooves are formed, and the key is inserted across the two key grooves formed in the shaft and the key groove on the inner peripheral surface of the cylindrical hole of the work, 2
The key of the book can be inserted securely. In addition, the center of the shaft coincides with the center of the cylindrical hole, so that the eccentricity between the shaft and the work is prevented.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a broach guide jig for processing a key groove according to the present invention, and FIGS. 2 and 3 show a method of forming two key grooves on the inner peripheral surface of a cylindrical hole of a work using the broach guide jig. .

In FIG. 1, a broach guide jig (1) for processing a key groove has a polygonal shape with a transverse cross section, and has on its outer peripheral surface one broach guide groove (2) extending in the longitudinal direction, and the same length as the broach guide groove (2). And a positioning key insertion groove (3) extending in the vertical direction and spaced 180 degrees in the circumferential direction from the broach guide groove (2). In addition, the broach guide jig (1) extends in the length direction of the broach guide jig (1) at a position spaced 120 degrees clockwise and counterclockwise in FIG. 1 from the broach guide groove (2) on the outer peripheral surface of the broach guide jig (1). Two planes (4) and (5) having equal widths are formed. These planes (4) and (5) serve as contact portions (6) and (7) that come into contact with the inner peripheral surface of the cylindrical hole (W1) when the keyway is formed. Naturally, the contact portions (6) and (7) are separated from each other by 120 degrees in the circumferential direction, and the broach guide groove (2) and the contact portions (6) and (7) are equiangular in the circumferential direction. That is, they are formed at intervals. In a cross section, a straight line passing through the center of the width of the broach guide groove (2)
(L1) and a straight line passing through the center of the width of each contact part (6) (7) (L2) (L3)
And the intersection (P) and the distance (D) between the intersection (P) and both side edges of each contact portion (6) (7) are equal to the radius of the cylindrical hole (W1) of the work (W), respectively. . The length of a straight line connecting the intersection (P) and other parts on the outer peripheral surface of the broach guide jig (1) is the same as the intersection (P) and both side edges of each contact portion (6) (7). Distance (D)
It is shorter than.

Such a broach guide jig for processing a key groove.
The method for forming key grooves extending in the length direction at positions 180 degrees apart in the circumferential direction on the inner peripheral surface of the cylindrical hole (W1) of the work (W) using (1) is as follows.

First, the broach guide jig (1) is inserted into the cylindrical hole (W1) of the work (W) (see FIG. 1). Next, the key groove machining broach (B) is moved in the length direction with respect to the work (W) while being guided by the broach guide groove (2), and the cylindrical hole (B) of the work (W) is moved by the broach (B). W1) Cut the inner peripheral surface to form the first keyway (10) (see FIG. 2). At this time, the straight line (L1) passing through the center of the width of the broach guide groove (2) is
(6) The distance (D) between the intersection (P) of the straight line (L2) (L3) passing through the center of the width of (7) and the side edges of each contact part (6) (7) is
Since it is equal to the radius of the cylindrical hole (W1) of (W), and the broach guide groove (2) and the two contact portions (6) (7) are formed at equal angular intervals in the circumferential direction, Both side edges of the contact portions (6) and (7) are in line contact with the inner peripheral surface of the cylindrical hole (W1). Therefore, when cutting with the broach (B), the broach guide jig (1)
2. The broach guide jig (1) is prevented from shifting in the left-right direction in FIG. 2 due to the force acting on the first keyway formed as a result.
The straight line (L4) passing through the width center of (10) is
It will be located on the diameter passing through the center (O) of the cylindrical hole (W1) of (W).

Next, the broach guide jig (1) is moved to the work (W).
The first keyway (10) is rotated by 180 degrees around the central axis of the cylindrical hole (W1) to align the position of the first keyway (10) with the positioning key insertion groove (3), and the two grooves (10) (3) ) And insert the positioning key (K1) (see FIG. 3). Then brooch (B)
Is moved in the length direction with respect to the work (W) while being guided in the broach guide groove (2), so that the inner peripheral surface of the cylindrical hole (W1) of the work (W) is cut by the broach (B). A second keyway (not shown) is formed. At this time, in a manner similar to the case of forming the first keyway (10), a straight line passing through the center of the width of the formed second keyway is formed in a cross section of the cylindrical hole (W1) of the work (W). Located on the diameter passing through the center (O).

Therefore, the shaft is inserted into the cylindrical hole (W1) of the work (W) in which the two key grooves (10) are formed, and the two key grooves formed in the shaft and the work (W) are formed. The key can be inserted securely across the two key (10) grooves, and the center of the shaft coincides with the center of the cylindrical hole (W1). As a result, the eccentricity between the shaft and the workpiece (W) is reduced. Is prevented.

In the above embodiment, the contact portions (6) and (7) that come into contact with the inner peripheral surface of the cylindrical hole (W1) when the keyway is formed are flat, and both side edges in the width direction are cylindrical holes (W1). It comes to line contact with the inner peripheral surface, but it is not limited to this,
For example, in the contact parts (6) and (7), the center of curvature is
It may be an intersection of a straight line passing through the center of the width of (2) and a straight line passing through the center of the width of each plane, and may be a partial cylindrical surface having the same curvature as the cylindrical hole (W1) of the work (W). In this case, the contact
(6) and (7) are in surface contact with the inner peripheral surface of the cylindrical hole (W1).

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in which a broach guide jig for processing a key groove according to the present invention is inserted into a cylindrical hole of a work.

FIG. 2 is a cross-sectional view showing a method of forming a first key groove on the inner peripheral surface of a cylindrical hole of a work using the key groove machining broach guide jig according to the present invention.

FIG. 3 is a perspective view showing a method of forming a second key groove on the inner peripheral surface of a cylindrical hole of a work using the key groove machining broach guide jig according to the present invention.

FIG. 4 is a cross-sectional view showing a state in which a conventional broach guide jig for processing a key groove is inserted into a cylindrical hole of a work.

FIG. 5 is a cross-sectional view sequentially showing a method of forming two key grooves on the inner peripheral surface of a cylindrical hole of a work using a conventional key groove machining broach guide jig.

FIG. 6 is a cross-sectional view showing a state in which a workpiece and a shaft each having a keyway formed by the method shown in FIG. 5 are combined with a shaft.

[Explanation of symbols]

 (1): Broach guide jig for keyway machining (2): Broach guide groove (3): Positioning key insertion groove (6) (7): Contact part (B): Broach (W): Workpiece (W1): Cylindrical hole

Claims (2)

[Claims] 1. A key groove machining broach guide jig for forming a key groove extending in a length direction of a work on an inner peripheral surface of a cylindrical hole of a work, and extending on the outer peripheral surface in a length direction thereof. A broach guide jig for processing a key groove in which one broach guide groove and two contact portions which also extend in the length direction and contact the inner peripheral surface of the cylindrical hole when forming the key groove are formed at equal angular intervals in the circumferential direction. . 2. The broach guide jig for processing a key groove according to claim 1, wherein a positioning key insertion groove extending in a longitudinal direction is formed at a position 180 degrees in a circumferential direction from the broach guide groove on the outer peripheral surface.