JP2002113614A - Helical broach - Google Patents

Abstract

PROBLEM TO BE SOLVED: To machine the tooth crest and tooth flank of a work with high concentricity. SOLUTION: Six streaks of cutting edges are integrally and spirally formed on the outer peripheral surface of a body 10, and the cutting edges are set to form tooth space machining blades 11a-11f at the front part 10a of the body, the four cutting edges out of the six cutting edges are set to form tooth flank machining edges 12a-12d and the remaining two cutting edges are set to form tooth crest machining edges 13a, 13b on the rear side 10b of the body. The tooth crest machining edges 13a, 13b are set to have a shape formed by cutting off the outer periphery of the tooth flank machining edges 12a-12d and the rear side part of the body. The depth L of the tooth space machining edges 11a-11f gets shallower as it goes toward further front side of the body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a broach,
In particular, the present invention relates to a helical broach for processing a helical internal gear, a helical internal spline groove, and the like.

[0002]

2. Description of the Related Art Hitherto, as this kind of helical broach, one disclosed in Japanese Patent Application Laid-Open No. Hei 10-202422 is known. Such a helical brooch,
A long body having a tooth groove machining blade for machining a tooth groove in a work near the tension portion between the tension portion and the rear support portion, and a tooth surface machining blade for finishing the tooth surface on an outer peripheral surface. In addition, a cylindrical shell blade having a tip surface machining blade for machining the tip surface on the outer peripheral surface is assembled near the rear support portion between the tension portion and the rear support portion of the main body.

[0003] The tooth groove machining blade provided on the main body has a plurality of blade portions formed on the outer edge along the circumferential direction, has a dish shape coaxial with the main body, and has a plurality of blades along the axial direction of the main body. Is formed. Further, the tooth flank processing blade provided on the shell blade has a plurality of blade portions formed at predetermined intervals at an outer edge and is spirally twisted to form two teeth, and the tooth tip surface processing blade is round at the outer edge. A single blade is formed by forming a blade-like blade portion and twisting spirally.

[0004] The helical broach as described above also processes the tooth tip surface with the shell blade for processing the tooth surface of the work, thereby processing the tooth tip surface and the tooth surface almost at the same time, resulting in misalignment of the main body with respect to the work. And other adverse effects as small as possible.

[0005]

However, in such a helical broach in which the shell blade is assembled to the main body, a slight gap is formed between the main body and the shell blade in order to improve the precision of machining the tooth surface of the work. Due to being formed and the mounting error of the shell blade to the main body, when processing the workpiece, the shell blade rattles against the main body, and the center of the shell blade is eccentric from the center axis of the main body, Processing accuracy may be impaired. Further, since the tooth groove processing blade is formed in a dish shape, a torsion tooth tip surface processing blade provided on the shell blade from the tooth groove processing blade provided on the body when cutting by the tooth groove processing blade or When shifting to a tooth flank cutting blade, the cutting edge bites into the workpiece intermittently, and there is also a problem that the cutting resistance fluctuates greatly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a broach capable of processing a tooth tip surface and a tooth surface of a work with high concentricity.

[0007]

Means for Solving the Problems To solve the above problems,
In order to achieve such an object, the present invention employs the following configuration. That is, in the helical broach according to claim 1, a plurality of cutting blades are formed in a spiral shape on the outer peripheral surface of the main body, and the cutting blades are tooth groove processing blades on the front side of the main body.
On the rear side of the main body, a part of the cutting blade is a tooth surface processing blade, and the remaining cutting blade is a cutting edge processing blade. According to the present invention having such a configuration, since the tooth surface machining blade and the tooth tip surface machining blade are formed integrally with the main body,
Eccentricity due to rattling as in the prior art does not occur. further,
Since the tooth groove machining blade, tooth flank machining blade and tooth tip machining blade are continuously formed in a spiral shape over the entire length of the main body, the biting to the work is continuous, and the cutting blade is always attached to the work. , So that the cutting resistance at the time of cutting the work is stabilized.

[0008] In the helical broach according to claim 2,
The tooth tip machining blade is characterized in that the outer periphery of the tooth machining blade and the rear part of the main body are cut off. With such a configuration, a large groove width can be secured between the tooth flank processing blade and the tooth flank processing blade adjacent to the rear side in the longitudinal direction of the main body of the tooth flank processing blade. Re-grinding of the blade becomes easy.

[0009] In the helical broach according to claim 3,
The tooth groove machining blade is characterized in that the depth of the groove is smaller toward the front side of the main body. With such a configuration, the strength of the tooth groove machining blade on the front side of the main body on which a large load acts during cutting can be increased.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a side view showing the overall schematic structure of the helical broach according to the present embodiment, and FIG.
FIG. 3 is an enlarged cross-sectional view of a main part of the tooth groove processing blade of the helical broach in the longitudinal direction of the main body. FIG. 3 is an enlarged perspective view of a main part of the tooth surface processing blade of the helical broach. It is a principal part expanded sectional view in the longitudinal direction of a main body of a tooth tip surface processing blade. FIG. 5 is an explanatory diagram of the processing of the work to be broached.

As shown in FIG. 1, the helical broach according to the present embodiment has a pulling portion 1 at one end of a rod-shaped main body 10.
5 are formed, and a rear support portion 16 is formed at the other end. Further, on the outer peripheral surface of the main body 10, six cutting blades spirally twisted with constant leads equal to each other over the entire length of the outer peripheral surface of the main body 10 are formed at equal intervals in the circumferential direction. At a substantially central portion in the longitudinal axis direction of the main body 10, a groove 14 for a swing receiver is formed to support a long helical broach.

Here, 6 is formed on the outer peripheral surface of the main body 10.
The cutting edges of the stripes are tooth groove machining blades 11a to 11f in the main body front part 10a located on the front side (pulling part 15 side) of the main body 10, and are located on the rear side of the main body 10 (rear supporting part 16 side). In the rear part 10b of the main body, four of the six teeth are the tooth flank cutting blades 12a to 12d, and the remaining two are the tooth flank cutting blades 13
a, 13b.

As shown in FIG. 1, the tooth-grooving blades 11a to 11f are formed with a plurality of blades formed on the outer edge along the circumferential direction, and are spirally twisted to form six teeth. The diameter of the portion is set to be larger as it is located on the rear side of the main body 10. In addition, the tooth groove machining blades 11a to 11
The plurality of blades provided on the main body 10 have a cross-sectional shape in the longitudinal axis direction of the main body 10 and protrude toward the outer peripheral side of the main body 10, as shown in FIG. The front peripheral surface of the land 21a is formed as a rake face 21.
b, the rear peripheral surface is the rear surface 21d, and the cutting edge 21c is formed at the intersection ridge line between the land 21a and the rake surface 21b. Further, as described above, the diameter of the outer diameter portion of the tooth groove machining blades 11a to 11f increases toward the rear side,
The core thickness of the main body 10 is formed with a smaller gradient than that of the main body 10 so as to be larger toward the rear side, whereby the groove depth L of the tooth groove machining blades 11a to 11f becomes shallower toward the front side of the main body 10. It is formed as follows. The forward portion of the main body front portion 10a of the tooth groove machining blades 11a to 11f is a chamfered blade.

As shown in FIG. 4, the tooth flank cutting blades 12a to 12d and the tooth tip flank cutting blades 13a and 13b are provided at 1, 3, 4, and 6 of the six cutting blades. ~ 12
d is formed, and the tooth surface machining blades 13a, 13
The arrangement is such that b is formed. Tooth surface processing blade 1
As shown in FIG. 1, 2a to 12d have a plurality of blade portions formed at the outer edge along the circumferential direction, are spirally twisted, and are formed continuously from the tooth groove machining blades 11a, 11c, 11d, 11f. In addition, the tooth tip surface machining blades 13a and 13b have a round blade-like blade portion formed on the outer edge along the circumferential direction, and are spirally twisted and formed continuously from the tooth groove machining blades 11b and 11e. Have been.

The blade portions provided on the tooth surface processing blades 12a to 12d have a sectional shape in the longitudinal axis direction of the main body 10, and are shown in FIGS.
As shown in the figure, similarly to the tooth groove machining blades 11a to 11f, a flat land 22a protrudes to the outer peripheral side of the main body 10 and is formed on the outer peripheral edge thereof.
b, the rear peripheral surface is the rear surface 22d, and the rake surface 22b
A cutting edge 22c is formed at the intersection ridge portion between the tooth and the tooth profile side surface 22e. Further, as shown in FIG. 4, the cross-sectional shape in the longitudinal axis direction of the main body 10 of the round blade-shaped blade portion provided on the tooth tip processing blades 13a and 13b is the outer periphery and the rear surface of the tooth surface processing blades 12a to 12d. 22d part is scraped off, land 23a,
The rear surface 23d is formed, and the land 23a
A cutting edge 23c is formed at the intersection ridge line between the rake face 23b, which is a peripheral surface on the front side thereof, and the rake face 23b.

Here, since the tooth tip machining blades 13a and 13b are shaped such that the back surface 22d of the tooth tip machining blades 12a to 12d is shaved off, the tooth tip machining blades 13a and 13b are cut off.
a, 13b, the back surface 23d and the tooth surface machining blades 13a, 13b
The groove width between the rake face 22b of the tooth flank machining blades 12b and 12d adjacent to the rear side in the longitudinal axis direction of the main body 10 is larger than the other groove widths. Further, the tooth tip machining blade 1
The land width b of 3a and 13b is the tooth surface machining blades 12a to 12d
Is set so as to be the same as the land width a.

When the inner surface broaching is performed on the work 30 as shown in FIG. 5 using the helical broach configured as described above, the work 30
a to 11f cut the tooth space 31 and then the tooth surface machining blade 1
2a to 12d cut and finish the tooth surface 32, and the tooth tip surface processing blades 13a and 13b cut and finish the tooth tip surface 33, so that a helical internal spline groove and the like are formed in the work 30. .

According to the helical broach according to the present embodiment, the tooth surface processing blades 12a to 12d and the tooth tip surface processing blades 13a,
Since the member 13b is formed integrally with the main body 10, eccentricity due to rattling as in the related art does not occur, and the tooth tip surface 33 and the tooth surface 32 of the work 30 can be finished with high concentricity. Furthermore, the tooth groove machining blades 11a to
11f, tooth surface processing blades 12a to 12d and tooth tip surface processing blade 1
Since 3a and 13b are continuously formed in a spiral shape, the bite to the work 30 becomes continuous, and the cutting edge of the work 30 is always bitten. The cutting resistance at the time is stable, and more precise processing is possible.

Further, the back surface 23d of the tooth tip machining blades 13a, 13b and the tooth surface machining blades 12b, 12d adjacent to the body 10 of the tooth tip machining blades 13a, 13b on the rear side in the longitudinal axis direction.
Since the large groove width between the rake face 22b and the rake face 22b is ensured, the re-grinding of the tooth flank processing blades 12b and 12d becomes easy. Further, in the tooth groove processing blades 11a to 11f, since the blade groove depth L becomes shallower toward the front side of the main body, the tooth groove processing on the front side of the main body in which a large load acts by first biting into the work at the time of cutting. The strength of the blades 11a to 11f can be increased for the blades 11a to 11f, and more stable cutting can be performed.

In this embodiment, the number of spiral cutting blades formed on the outer periphery of the main body 10 is six.
In b, two of the six cutting blades are tooth tip surface processing blades 13a, 13
The number of the cutting edges is not limited to this, but may be less than six or more than six, and the number of tooth tip surface machining blades may be one or more.

[0021]

According to the present invention, the following effects can be obtained. According to the first aspect of the present invention, since the tooth flank processing blade and the tooth flank processing blade are formed integrally with the main body, the conventional eccentricity due to rattling does not occur, and the tooth flank and the tooth flank are not formed. The tooth surface can be finished with high concentricity. Furthermore, since the tooth groove machining blade, the tooth surface machining blade and the tooth tip machining blade are continuously formed in a spiral shape over the entire length of the main body,
Since the biting to the work becomes continuous and the cutting edge always bites into the work, the cutting resistance at the time of cutting the work is stabilized, and the gear can be finished with higher precision.

According to the second aspect of the present invention, the tooth tip machining blade is shaped such that the outer periphery of the tooth tip machining blade and the rear part of the main body are cut off. A large groove width can be secured between the processing blade and the adjacent tooth surface processing blade on the rear side in the longitudinal direction of the main body, so that the tooth surface processing blade can be easily re-ground.

According to the third aspect of the present invention, in the tooth groove machining blade, since the depth of the blade groove becomes shallower toward the front side of the main body, the tooth on the front side of the main body on which a large load acts during cutting. The more the grooving blade, the greater its strength, and the more stable the cutting.

[Brief description of the drawings]

FIG. 1 is a side view showing the overall schematic structure of a helical broach according to the present embodiment.

FIG. 2 is an enlarged cross-sectional view of a main part of a helical broach of the helical broach according to the embodiment in a longitudinal axis direction of a main body.

FIG. 3 is an enlarged perspective view of a main part of a tooth surface machining blade of the helical broach according to the present embodiment.

FIG. 4 is an enlarged cross-sectional view of a main part of the helical broach according to the embodiment in the longitudinal axis direction of the tooth surface processing blade and the tooth tip processing blade.

FIG. 5 is an explanatory diagram of processing of a work.

[Explanation of symbols]

Reference Signs List 10 Main body 10a Main body front portion 10b Main body rear portion 11a, 11b, 11c, 11d, 11e, 11f Tooth groove processing blade 12a, 12b, 12c, 12d Tooth surface processing blade 13a, 13b Tooth surface processing blade 15 Pulling portion 16 Rear support Part 30 Work 31 Tooth groove 32 Tooth surface 33 Tooth surface

Claims (3)

[Claims] 1. A plurality of cutting blades are formed on the outer peripheral surface of a main body in a spiral shape integrally with the main body, and the cutting blade is a tooth groove machining blade at a front side of the main body, and is partially formed at a rear side of the main body. A helical broach, wherein the cutting edge of the helical broach is a tooth surface processing blade and the remaining cutting edge is a tooth tip surface processing blade. 2. The helical broach according to claim 1, wherein the tooth tip machining blade has a shape obtained by cutting off an outer periphery of the tooth surface machining blade and a rear part of a main body. brooch. 3. The helical broach according to claim 1, wherein the tooth groove machining blade has a blade groove depth that becomes shallower toward the front of the main body.