JP4488221B2 - Broach for internal gear machining - Google Patents

Description

  The present invention relates to an internal gear machining broach used for finishing an internal gear that is a workpiece, and in particular, for finishing an internal gear having a workpiece having a Rockwell hardness of 45 to 65 HRC. The present invention relates to an internal gear machining broach used.

When broaching the left and right flank surfaces of the internal gear, which is a conventional workpiece, and the large diameter portion and the small diameter portion, the large diameter portion is formed by a broach having one large diameter portion cutting blade and a small diameter portion cutting edge And finishing the left and right flank surfaces in the tooth width direction with another broach having a pair of left and right flank face cutting blades, or as described in Patent Document 1, After finishing the large diameter part with a broach with a large diameter cutting edge, finish the small diameter part and the left and right flank surfaces in the tooth width direction simultaneously with another broach with a small diameter cutting edge and left and right flank cutting edges. I was processing.
Japanese Utility Model Publication No. 6-27297

  However, in the conventional broaching method for broaching the left and right flank surfaces of the internal gear, which is a conventional workpiece, and the large diameter portion and the small diameter portion, the work length of the internal gear, which is the workpiece, is set. On the other hand, the axial interval of each broach cutting blade is increased, and one of the flank cutting blade, large diameter cutting blade, or small diameter cutting blade is not involved in cutting during broaching, so it does not participate in cutting. As a result, the broach shaft center moved slightly toward the cutting edge, and the position accuracy of the broach shaft center during broaching was not stable, and finishing of the internal gear that guarantees stable machining accuracy was not possible. In particular, the position accuracy of the internal gear machining broach shaft used for finishing internal gears having a Rockwell hardness of 45 to 65 HRC was not stable.

The object of the present invention is to solve the above-mentioned problem, making the flank cutting edge, the large diameter part cutting edge or the small diameter part cutting edge during broaching involved any cutting, and the position of the broach axis during broaching. It is an object of the present invention to provide a broach for internal gear machining used for finishing an internal gear that stabilizes accuracy and guarantees stable machining accuracy.
Another problem of the present invention is that, in particular, in an internal gear machining broach used for finishing an internal gear having a Rockwell hardness of 45 to 65 HRC, the workpiece has a hardness of 45 to 65 HRC. An object of the present invention is to provide an internal gear machining broach that stabilizes positional accuracy and guarantees stable machining accuracy.

  For this reason, the present invention continues to the first blade having a pair of flank cutting blades that simultaneously cut the left and right flank surfaces of the internal gear that is the workpiece from the biting side toward the finishing side, and the first blade. A flank surface of the second blade, having alternately a second blade having a large-diameter cutting blade and a small-diameter cutting blade that make a pair for simultaneously cutting the large-diameter portion and the small-diameter portion of the internal gear. In order not to cut the cutting blade, the pressure angle β2 is made smaller than the pressure angle β1 of the flank cutting blade of the first blade, and the large-diameter cutting blade and the small-diameter cutting blade of the first blade perform cutting. The above-mentioned problems have been solved by an internal gear machining broach characterized in that each height is made smaller than the respective heights of the large-diameter part cutting edge and the small-diameter part cutting edge of the second blade so as not to be performed.

  In the present invention, a first blade having a pair of flank cutting blades that simultaneously cut the left and right flank surfaces of the internal gear that is a workpiece from the biting side toward the finishing side, and the inner blade that follows the first blade. Since it has alternately the 2nd blade | edge which has the large diameter part cutting edge which makes the pair which cuts the large diameter part and small diameter part of a toothed gear simultaneously, and a small diameter part cutting edge, it is paired with a pair of flank face cutting blades The large-diameter part cutting edge and the small-diameter part cutting edge that form the same are involved in cutting at the same time, and all the cutting edges constrain the work surface of the internal gear during broaching, and the position of the broach axis center during broaching The present invention provides a broach for internal gear machining used for finishing an internal gear that stabilizes accuracy and guarantees stable machining accuracy.

  Preferably, an axial interval between the first blade and the second blade is made smaller than an axial work length of an internal gear that is a work piece, and the first blade and the second blade are in the broach cutting. By making sure that the part of the internal gear is engaged in the cutting process at the same time, even for work pieces with a short cutting length, the broach cutting edge length can be shortened to achieve highly efficient broaching and broaching. The present invention provides a broach for internal gear machining used for finishing an internal gear that stabilizes the positional accuracy of the broach shaft center and guarantees stable machining accuracy.

More preferably, the rake angle of the flank cutting edge of the first blade is θ1, the rake angles of the large diameter part cutting blade and the small diameter part cutting edge of the second blade are θ2, and θ1, θ2 are
0 ° ≧ θ1 ≧ −30 °
0 ° ≧ θ2 ≧ −30 °
By setting to, the position accuracy of the broach shaft center during the broaching process is stabilized by finishing the internal gear with a workpiece hardness of 45 to 65 HRC, ensuring a stable machining accuracy. Therefore, it is possible to provide a broach for internal gear machining used for finishing of internal gears.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an overall side view of an internal gear machining broach showing an embodiment of the present invention, FIG. 2A is a schematic partial enlarged view of the first blade 1 and the second blade 2 of FIG. 1, and FIG. Each schematic front view which looked at the 1st blade 1 and the 2nd blade 2 of (a) from the A arrow direction is shown. The internal gear machining broach 58 of the present invention is a pair of flank surfaces for simultaneously cutting the left and right flank surfaces of an internal gear, which is a workpiece not shown, from the biting side 52 to the finishing side 55 in the tooth thickness direction. The first blade 1 having the cutting blades 1a and 1b, and the large-diameter portion cutting blade 2c and the small-diameter portion cutting blade 2d that make a pair for simultaneously cutting the large-diameter portion and the small-diameter portion of the internal gear following the first blade 1 The flank cutting edges 2a and 2b of the second blade 2 have their pressure angles β2 set to be different from those of the flank cutting edges of the first blade. The large angle cutting edge 1c and the small diameter cutting edge 1d of the first blade are made smaller than the pressure angle β1, and the respective heights Ha and Da are set to the respective large diameter cutting of the second blade so that cutting is not performed. The heights Hb and Db of the blade 2c and the small diameter portion cutting blade 2d are made smaller. In FIG. 1, 51 is a front gripping part, 50 is a guide, 53 is a broach body, 54 is a broaching blade part, and 56 is a rear gripping part. In FIG. 2A, α1 and α2 are clearance angles of the large-diameter portion cutting blade 1c and the small-diameter portion cutting blade 1d of the first blade, respectively.

  In the embodiment of the present invention, a pair of flank cutting blades 1a, which simultaneously cut in the tooth thickness direction the left and right flank surfaces of an internal gear which is a workpiece (not shown) from the biting side 52 toward the finishing side 55. A first blade 1 having 1b, and a first blade 1 having a large-diameter portion cutting blade 2c and a small-diameter portion cutting blade 2d that form a pair for simultaneously cutting the large-diameter portion and the small-diameter portion of the internal gear following the first blade 1. Since there are two blades 2 alternately, the large-diameter cutting blade and the small-diameter cutting blade paired with a pair of flank cutting blades are simultaneously involved in cutting, and all the cutting blades are inside during broaching. Provided is a broach for internal gear machining used for finishing internal gears that constrains the work surface of the tooth gear, stabilizes the positional accuracy of the broach axis during broaching, and guarantees stable machining accuracy. It became a thing.

  In the embodiment of the present invention, the axial distance L between the first blade 1 and the second blade 2 is made smaller than the axial work length of an internal gear, which is a work piece (not shown), and the first gear 1 is cut during broach cutting. By ensuring that the 1st blade 1 and 2nd blade 2 are involved in the cutting of the internal gear at the same time, it is possible to shorten the broach cutting edge length even for workpieces with short cutting lengths. Provided is a broach for internal gear machining that is capable of high-efficiency broaching, stabilizes the position accuracy of the broach axis during broaching, and guarantees stable machining accuracy. It was.

More preferably, the rake angle of the flank cutting edge of the first blade is θ1, the rake angles of the large diameter part cutting blade and the small diameter part cutting edge of the second blade are θ2, and θ1, θ2 are
FIG. 3 is a schematic partial enlarged view of the first blade and the second blade of FIG. 1, which is an embodiment of the present invention different from FIG. 2 (a). In this embodiment, the flank surface of the first blade 11 is shown. The rake angles of the cutting edges 11a and 11b are θ1, the rake angles of the large diameter cutting edge 12c and the small diameter cutting edge 12d of the second blade 12 are θ2, and θ1 and θ2 are 0 ° ≧ θ1 ≧ −30 °
0 ° ≧ θ2 ≧ −30 °
By setting to, the finish accuracy of the internal gear with a Rockwell hardness of 45 to 65 HRC, which stabilizes the position accuracy of the broach axis during broaching, and guarantees stable machining accuracy. Therefore, it is possible to provide a broach for internal gear machining used for finishing of internal gears. Each schematic front view of the first blade 11 and the second blade 12 in FIG. 3 as viewed from the direction of the arrow A in FIG. 3 is the same as FIG.

Preferably, the rake angle θ1 of the flank cutting edges 11a, 11b of the first blade 11 and the rake angles θ2 of the large diameter cutting edge 12c and the small diameter cutting edge 12d of the second blade 12 are:
−10 ° ≧ θ1 ≧ −20 °
−5 ° ≧ θ2 ≧ −15 °
By setting to, the position accuracy of the broach shaft center during broaching, which finishes internal gears with a Rockwell hardness of 45 to 65 HRC, is more stable and the machining accuracy is more stable. It is possible to provide a broach for internal gear machining used for finish machining of internal gears that guarantees the above.

  In the present invention, a first blade having a pair of flank cutting blades that simultaneously cut the left and right flank surfaces of the internal gear that is a workpiece from the biting side toward the finishing side, and the inner blade that follows the first blade. Since it has alternately the 2nd blade | edge which has the large diameter part cutting edge which makes the pair which cuts the large diameter part and small diameter part of a toothed gear simultaneously, and a small diameter part cutting edge, it is paired with a pair of flank face cutting blades The large-diameter part cutting edge and the small-diameter part cutting edge that form the same are involved in cutting at the same time, and all the cutting edges constrain the work surface of the internal gear during broaching, and the position of the broach axis center during broaching The present invention provides a broach for internal gear machining used for finishing an internal gear that stabilizes accuracy and guarantees stable machining accuracy.

The whole side view of the internal gear processing broach showing an embodiment of the invention (A) is a schematic partial enlarged view of the first blade 1 and the second blade 2 of FIG. 1, and (b) is a schematic front view of the first blade 1 and the second blade 2 of FIG. FIG. FIG. 2 is a schematic partial enlarged view of the first blade and the second blade of FIG. 1 which is an embodiment of the present invention different from FIG.

Explanation of symbols

1, 11: First blade 1a, 1b: Flank face cutting blade of the first blade 1c: Large diameter portion cutting blade of the first blade
1d: Small-diameter cutting edge of the first blade 2, 12: Second blade 2a, 2b: Flank face cutting blade of the second blade
2c: Large diameter cutting edge of the second blade 2d: Small diameter cutting edge of the second blade
52: Biting side 55: Finishing side 58: Broach for internal gear machining
Da: Small diameter part height of the first blade Db: Small diameter part height of the second blade
Ha: Large-diameter portion height of the first blade Hb: Large-diameter portion height of the second blade β1: Pressure angle of the flank cutting blade of the first blade β2: Pressure angle θ1 of the flank cutting blade of the second blade: Rake angle of the 1st blade flank cutting edge
θ2: Each rake angle between the large diameter cutting edge 12c and the small diameter cutting edge 12d of the second blade

Claims (4)

  A first blade having a pair of flank face cutting blades that simultaneously cut the left and right flank surfaces of the internal gear that is a work piece from the biting side toward the finishing side, and the large size of the internal gear that follows the first blade The second blade having a large-diameter portion cutting blade and a small-diameter portion cutting blade forming a pair for simultaneously cutting the diameter portion and the small-diameter portion are alternately provided, and the flank cutting edge of the second blade performs cutting. The pressure angle β2 is made smaller than the pressure angle β1 of the flank cutting edge of the first blade so that the large diameter cutting edge and the small diameter cutting edge of the first blade do not perform cutting. An internal gear machining broach characterized in that the height is made smaller than the respective heights of the large diameter cutting edge and the small diameter cutting edge of the second blade.   The axial distance between the first blade and the second blade is made smaller than the axial work length of the internal gear, which is the workpiece, so that the first blade and the second blade are the inner teeth during broach cutting. 2. An internal gear machining broach according to claim 1, wherein cutting is simultaneously performed in a portion to be machined of the gear. The rake angle of the flank cutting edge of the first blade is θ1, the rake angles of the large diameter part cutting edge and the small diameter part cutting edge of the second blade are θ2, and θ1, θ2 are
0 ° ≧ θ1 ≧ −30 °
0 ° ≧ θ2 ≧ −30 °
The internal gear machining broach according to claim 1 or 2, wherein finishing of an internal gear having a Rockwell hardness of 45 to 65 HRC, the hardness of the workpiece set to be, is set. The rake angle of the flank cutting edge of the first blade is θ1, the rake angles of the large diameter part cutting edge and the small diameter part cutting edge of the second blade are θ2, and θ1, θ2 are
−10 ° ≧ θ1 ≧ −20 °
−5 ° ≧ θ2 ≧ −15 °
The internal gear machining broach according to claim 1 or 2, wherein finishing of an internal gear having a Rockwell hardness of 45 to 65 HRC, the hardness of the workpiece set to be, is set.

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