JP2011121158A - Cutting device and method of cutting commutator material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting device capable of restricting friction between a workpiece and a metal saw and outbreaks of burrs. <P>SOLUTION: A metal saw 31 is formed into a disk-like shape having a plurality of blade parts 33 in the periphery thereof. The blade part 33 has a main cutting part 34 for cutting a workpiece 11 in one side end in the thickness direction in the tip of the blade part 33, and has an auxiliary cutting part 36, which is provided on the tip side of the blade part 33 than a relief part 35 inclined so that the thickness of the blade part 33 is formed thinner as it goes to the tip side of the blade part 33 and which can cut the workpiece 11, in the other side end in the thickness direction. This cutting device cuts the workpiece 11 by rotating the metal saw 31 and while relatively moving the metal saw 31 and the workpiece 11 to each other. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cutting device that cuts a workpiece with a metal saw, and a method of dividing a commutator material that forms a segment by dividing the commutator material with the cutting device.

  Conventionally, a plurality of segments constituting a commutator of a motor is a disc-shaped commutator material formed by forming a conductive metal plate into a cylindrical shape and having a plurality of blade portions on the outer periphery provided in the cutting device. It is formed by dividing in the circumferential direction with a metal saw (circular saw). And as a metal saw with which a cutting device is equipped, there exists a thing described in patent document 1, for example.

  The blade portion of the metal saw described in Patent Document 1 has a cutting edge that cuts a workpiece (for example, a commutator material) at the distal end thereof, and is thicker than the cutting edge on the base end side than the cutting edge. It has a thin bladeless part. Therefore, the blade has the largest cutting edge at the tip, and when the workpiece is cut with this metal saw, a groove having the same width as the thickness of the cutting edge is formed in the workpiece. Further, chips generated when the workpiece is cut with the metal saw are discharged to the outside of the groove through a gap between the inner surface of the groove formed in the workpiece and the bladeless portion.

JP-A-10-263911

  However, when the workpiece is cut with the metal saw described in Patent Document 1, both end portions in the thickness direction of the cutting edge 101 are formed on the inner side surface 102a of the cut groove 102 as shown in FIG. Since they are in sliding contact with each other, there is a possibility that chips are welded to the inner side surface 102 a due to frictional heat between the cutting edge 101 and the inner side surface 102 a, and burrs are generated inside the groove 102.

  Further, as shown in FIG. 9B, since the thickness W11 of the cutting edge 101 is equal to the width W13 of the groove 102 to be cut, the width W13 of the chip 103 generated along with the cutting is the groove 102. A width equal to W12 appears. Then, when the chip 103 is pushed and discharged by the blade portion 104 in the rotation direction of the metal saw (in FIG. 9B, the direction from the back side to the front side of the paper), both ends in the width direction of the chip 103 are discharged. The portion (the portion surrounded by the broken line in FIG. 9B) is in sliding contact with the inner side surface 102a of the groove 102 to generate heat, and the chips 103 may be welded to the inner side surface 102a and become burrs. 9A and 9B are views of the blade portion 104 as viewed from the front side in the rotation direction of the metal saw.

  For example, when a burr exists in a segment formed by dividing the commutator material, there is a possibility that segments adjacent in the circumferential direction are short-circuited by the burr. Therefore, it is desired to suppress the generation of burrs.

  The present invention has been made in view of such circumstances, and an object of the present invention is to use a cutting device capable of suppressing friction between a workpiece and a metal saw and suppressing generation of burrs, and the cutting device. An object of the present invention is to provide a method for dividing commutator material.

  In order to solve the above-mentioned problem, the invention described in claim 1 rotates a disk-shaped metal saw having a plurality of blade portions on the outer periphery, and the metal saw and the workpiece are orthogonal to the rotation direction of the metal saw. A cutting device that performs a cutting process on the workpiece by relatively moving in one direction, wherein the blade portion cuts the workpiece at one end in a thickness direction at a tip portion of the blade portion. A relief portion inclined to the thickness of the blade portion toward the tip end side of the blade portion, and a relief portion inclined to the tip end side of the blade portion at the other end portion in the thickness direction. Also, the gist of the invention is that it has an auxiliary cutting portion that is provided on the distal end side of the blade portion and can cut the workpiece.

  According to the same configuration, the blade portion provided with the relief portion at the end portion opposite to the side where the main cutting portion is provided (the end portion opposite to the blade portion in the thickness direction) is more distal than the escape portion. The portion on the side is thinner than the portion on the base end side relative to the escape portion. Therefore, it is possible to reduce the contact area between the end portion of the blade portion in the thickness direction where the relief portion is provided and the inner surface of the groove cut in the workpiece. When the contact area between the inner surface of the groove and the blade portion is reduced, the friction between the workpiece and the metal saw can be reduced, and the generation of frictional heat is suppressed. Is suppressed, and the generation of burrs is suppressed. Further, in the blade portion having the relief portion, the portion that cuts the workpiece on the distal end side relative to the relief portion (that is, the portion provided with the main cutting portion and the auxiliary cutting portion) is the portion on the proximal end side of the blade portion. Therefore, the width of chips generated when the workpiece is cut is smaller than the width of the groove to be cut. Accordingly, since the chips are prevented from sliding on the inner side surface of the groove, it is possible to suppress chips from being welded to the inner side surface of the groove to become burrs and to improve the chip discharging property. In addition, since an auxiliary cutting part capable of cutting the workpiece is provided on the tip side of the relief part in the blade part, the work piece can be cut even on the relief part side, and the work piece is not sheared. It is suppressed that it remains in. Therefore, the generation of burrs can be suppressed.

  According to a second aspect of the present invention, in the cutting device according to the first aspect, when the blade portion is viewed from the rotation direction of the metal saw, a cutting side surface extending from the auxiliary cutting portion toward the escape portion is: The gist is that the inclination with respect to the side surface of the blade portion extending from the main cutting portion to the base end side of the blade portion is smaller than that of the escape portion.

According to this configuration, in the blade portion, it is easy to ensure the cutting ability even in the auxiliary cutting portion on the opposite side to the main cutting portion (the opposite side in the thickness direction of the blade portion).
According to a third aspect of the present invention, in the cutting apparatus according to the first or second aspect, the plurality of blade portions arranged in the circumferential direction are staggered in the thickness direction of the metal saw on the side having the main cutting portion. The gist of this is.

According to this configuration, when the metal saw rotates, the main cutting portions alternately pass through both sides in the width direction of the groove to be cut, so that the generation of burrs can be further suppressed.
The invention according to claim 4 is a method of dividing a commutator material, in which a cylindrical commutator material made of a conductive metal material is divided in the circumferential direction to form a plurality of segments. A positioning step of positioning the metal saw and the commutator material provided in the cutting device according to any one of items 3 so that the metal saw has a cutting amount capable of dividing the commutator material in a circumferential direction. And cutting the commutator material along the axial direction with the metal saw by rotating the metal saw and relatively moving the metal saw and the commutator material in the axial direction of the commutator material; The gist is that

  According to this method, since the segments are formed by dividing the commutator material in the circumferential direction by a cutting device capable of suppressing the generation of burrs, the segments adjacent in the circumferential direction in the commutator are short-circuited by burrs. Is suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the cutting device which can suppress generation | occurrence | production of a burr | flash while suppressing the friction with a to-be-processed object and a metal saw small, and the cutting method of the commutator material using this cutting device can be provided.

(A) is a front view of a cutting device, (b) is a top view of a cutting device. The perspective view of a commutator. The perspective view of a workpiece | work. The front view of the metal saw of this embodiment. The partial expansion perspective view of the metal saw of this embodiment. (A) is a side view of a blade part, (b) is a perspective view of a blade part. (A) And (b) is a schematic diagram which shows a mode that a workpiece | work is cut with the metal saw of this embodiment. (A) And (b) is a schematic diagram which shows the workpiece | work cut with the metal saw of this embodiment. (A) And (b) is a schematic diagram which shows a mode that a workpiece is cut with the conventional metal saw.

Hereinafter, an embodiment in which the present invention is embodied in a cutting device for dividing a commutator material to form a segment will be described with reference to the drawings.
Fig.1 (a) is the schematic diagram which looked at the cutting device M of this embodiment from the front, and FIG.1 (b) is the schematic diagram which looked at the cutting device M from the upper direction. The cutting device M is used for manufacturing the commutator 1 that constitutes the armature of the DC motor.

  As shown in FIG. 2, the commutator 1 includes a cylindrical insulator 2 made of an insulating resin material, and eight segments 3 fixed to the outer peripheral surface of the insulator 2. The commutator 1 can rotate integrally with the rotary shaft when a rotary shaft (not shown) of the armature is press-fitted into a press-fit hole 2a that penetrates the central portion in the radial direction of the insulator 2 in the axial direction. Fixed to.

  The eight segments 3 are made of a conductive metal material (for example, copper), are arranged in parallel at equal angular intervals in the circumferential direction, and have a substantially strip shape extending in the axial direction. The length in the axial direction is The insulator 2 is formed substantially equal to the axial length. In addition, one end of each segment 3 in the axial direction (upper end in FIG. 2) is formed so that the width becomes narrower toward one end in the axial direction (upper end in FIG. 2). A connection claw 3a projects from one end surface in the axial direction. The connection claw 3a is bent radially outward at the base end so that the distal end of the connection claw 3a faces the other end side of the segment 3 (that is, the end on the side where the connection claw 3a is not provided). . The connection claw 3a is for connecting the end of an armature coil (not shown) constituting the armature.

  Further, a dividing groove 4 extending along the axial direction is provided between the segments 3 adjacent in the circumferential direction, and the segments 3 adjacent in the circumferential direction are separated by the dividing groove 4. Each dividing groove 4 is formed deeper inward in the radial direction than the thickness of each segment 3 (thickness in the radial direction), and is formed up to the insulator 2. Each dividing groove 4 is formed from one end to the other end in the longitudinal direction of the insulator 2. The width of the dividing groove 4 (the width along the circumferential direction of the commutator 1) is set to a value in the range of 0.35 to 0.45 mm, for example.

  The commutator 1 as described above is manufactured by cutting a workpiece 11 as a workpiece shown in FIG. Here, the workpiece 11 will be described. The workpiece 11 includes the insulator 2 and a commutator material 12 provided integrally on the outer periphery of the insulator 2.

  The commutator material 12 becomes the segment 3 and is formed of a conductive metal material (for example, copper). The rectangular main body 12a constituting the commutator material 12 is curved in the longitudinal direction, and both end surfaces in the longitudinal direction are in contact with each other, and are formed into a cylindrical shape. The inner peripheral surface of the material main body 12 a is in close contact with the outer peripheral surface of the insulator 2. Note that a plurality of projections (not shown) embedded in the insulator 2 and preventing the segment 3 from dropping off may be provided on the inner peripheral surface of the material main body 12a.

  Further, eight connecting claws 3a are formed so as to protrude from one end surface (upper end surface in FIG. 2) of the material body 12a formed in a cylindrical shape in the axial direction. The eight connecting claws 3a are formed at equal intervals in the longitudinal direction of the material body 12a (same as the circumferential direction in FIG. 2). Furthermore, a concave portion 12b that is recessed in a trapezoidal shape toward the central portion in the axial direction of the material main body 12a is formed between the adjacent connection claws 3a at one end portion in the axial direction of the material main body 12a. A total of eight recesses 12b are formed in the material body 12a, and one of the eight recesses 12b is a recess 12b of the material body 12a formed when the material body 12a is formed into a cylindrical shape. It is formed in a portion including a joint 12c (that is, a portion where both longitudinal end surfaces of the material main body 12a are in contact).

  For example, the workpiece 11 is formed in a cylindrical shape by curving the commutator material 12 in the longitudinal direction and then forming the cylindrical shape after filling the inside of the cylindrical commutator material 12 with an insulating resin material. The insulator 2 is formed.

  Next, the cutting device M will be described. As shown in FIGS. 1A and 1B, the support portion 21 constituting the cutting device M supports two main shafts 22 so as to be rotatable around a central axis L of the main shaft 22. The two main shafts 22 are arranged in parallel with each other, and the positions of the tips thereof are the same in the axial direction of the main shaft 22. A motor (not shown) is connected to the base end portion of each main shaft 22, and a disk-shaped metal saw 31 is fixed to the front end portion of each main shaft 22 so as to be integrally rotatable.

  As shown in FIG. 4, the disk-shaped metal saw 31 is fixed to the main shaft 22 with a fixing hole 32 penetratingly formed in the center portion in the radial direction and the main shaft 22 being inserted into the fixing hole 32. (See FIG. 1B). In addition, 20 blade portions 33 are formed in a saw blade shape on the outer peripheral edge of the metal saw 31, and the 20 blade portions 33 are formed at equal angular intervals in the circumferential direction.

  Each blade portion 33 has a substantially triangular plate shape whose width in the circumferential direction becomes narrower as the shape viewed from the axial direction of the metal saw 31 is directed from the proximal end portion on the radially inner side to the distal end portion on the radially outer side. ing. As shown in FIGS. 4 and 5, the front surface 33 a on the front side in the rotation direction of the metal saw 31 in each blade portion 33 has a planar shape parallel to the axial direction of the metal saw 31 (the same as the thickness direction of the metal saw 31). At the same time, the radially outer end protrudes slightly toward the front side in the rotational direction of the metal saw 31 than the radially inner end. In addition, the rear surface 33b on the rear side in the rotation direction of the metal saw 31 in each blade portion 33 has a planar shape parallel to the axial direction of the metal saw 31, and the end on the radially outer side is more than the end on the radially inner side. 31 is located on the front side in the rotation direction. Further, the flank 33c at the tip of each blade portion 33 forms a flat surface parallel to the axial direction of the metal saw 31, and radially inward of the metal saw 31 from the front side to the rear side in the rotation direction of the metal saw 31. Slightly inclined to head toward.

  Further, in the metal saw 31, the outer peripheral edge portion including the blade portion 33 from the radially outer end of the metal saw 31 to a predetermined position on the radially inner side becomes slightly thinner toward the inner side of the metal saw 31. It is formed as follows. Further, both side surfaces 33d in the thickness direction at the outer peripheral edge of the metal saw 31 are slightly so as to approach the central portion in the thickness direction of the metal saw 31 from the radially outer end of the metal saw 31 toward the radially inner side. It is inclined to. That is, the metal saw 31 of this embodiment has a so-called back taper. In addition, in the metal saw 31, the site | part inside this outer peripheral part is formed uniformly.

  As shown in FIG. 6A and FIG. 6B, a main cutting portion 34 is formed at one end portion in the thickness direction (the same as the axial direction of the metal saw 31) at the tip of each blade portion 33. Has been. In addition, at the tip of each blade 33, the other end in the thickness direction, that is, the end in the thickness direction opposite to the main cutting portion 34, is the same as moving toward the tip of the blade 33. An escape portion 35 made of an inclined surface that is inclined so as to reduce the thickness of the blade portion 33, and an auxiliary cutting portion 36 provided further on the tip side of the blade portion 33 than the escape portion 35 is formed.

  The main cutting portion 34 is a corner portion constituted by a front surface 33a, a relief surface 33c, and one side surface 33d. Further, the cutting side surface 33e between the relief portion 35 and the relief surface 33c has a flat shape, and the auxiliary cutting portion 36 is a corner portion constituted by the front surface 33a, the relief surface 33c, and the other side surface 33d. . The angle θ1 formed by the side surface 33d constituting the main cutting portion 34 and the flank 33c and the angle θ2 formed by the cutting side surface 33e and the flank 33c are formed to be equal. In the present embodiment, since the metal saw 31 has a back taper, the angles θ1 and θ2 are acute angles close to 90 °. The relief portion 35 is inclined by about 45 ° with respect to the side surface 33d of the blade portion 33 on the side where the relief portion 35 is provided. Furthermore, when the blade portion 33 is viewed from the rotation direction of the metal saw 31, the cutting side surface 33e is inclined with respect to the side surface 33d of the blade portion 33 on the side where the main cutting portion 34 is provided, and the inclination of the relief portion 35 with respect to the side surface 33d. Smaller than.

  Each blade portion 33 is provided with the relief portion 35, so that a portion on the distal end side with respect to the relief portion 35 is thinner than a portion on the proximal end side with respect to the relief portion 35. . Further, since the main cutting portion 34 is formed on one end in the thickness direction of each blade portion 33 and the auxiliary cutting portion 36 is formed on the other end at the tip of each blade portion 33, the workpiece 11 is cut on both sides in the thickness direction. Is possible.

  As shown in FIG. 5, in the metal saw 31 of the present embodiment, the 20 blade portions 33 are staggered in the thickness direction of the metal saw 31 on the side having the main cutting portion 34. Accordingly, the blade portions 33 adjacent to each other in the circumferential direction are opposite to each other in the thickness direction of the metal saw 31 on the side having the main cutting portion 34. For example, in FIG. 5, in order from the left, the leftmost blade portion 33 has a main cutting portion 34 on the front side of the paper surface, and the right adjacent blade portion 33 has a main cutting portion 34 on the back side of the paper surface. The right adjacent blade portion 33 has a main cutting portion 34 on the front side of the paper surface, and the right adjacent blade portion 33 further has a main cutting portion 34 on the back surface side of the paper surface.

  As shown in FIG. 1 (b), in the cutting apparatus M, the two metal saws 31 fixed to the tip portions of the main shafts 22 are considered to have a predetermined cut amount in the workpiece 11, and are spaced from each other. Is set. Specifically, the distance between the two metal saws 31 is set to be equal to the distance between the bottoms of the two dividing grooves 4 that are radially opposed to each other in the commutator 1. That is, the two metal saws 31 are spaced apart by a distance obtained by subtracting the depth of the dividing groove 4 formed from the outer diameter of the commutator material 12 of the workpiece 11. Further, the two metal saws 31 are disposed in opposite directions so that the workpiece 11 that passes relatively between the two metal saws 31 can be simultaneously cut. In this embodiment, the metal saw 31 disposed on the left side in FIG. 1A is rotated clockwise, and the metal saw 31 disposed on the right side is rotated counterclockwise. Moreover, the cutting device M of this embodiment is moved with respect to the workpiece | work 11 by moving to the one direction (refer arrow of the right side in Fig.1 (a)) orthogonal to the rotation direction of the metal saw 31 with the drive device which is not shown in figure. The workpiece 11 can move along the axial direction.

Next, a method of forming the segment 3 by dividing the commutator material 12 in the circumferential direction using the cutting device M will be described with reference to FIGS. 1 (a) and 1 (b).
First, a positioning process is performed, and the workpiece 11 and the metal saw 31 are positioned. At this time, a rotating shaft (not shown) is fixed to the work 11 so as to be integrally rotatable with the rotating shaft by being press-fitted into the press-fitting hole 2a. And the workpiece | work 11 is positioned with respect to the two metal saws 31 so that the metal saw 31 may have the cutting amount which can divide | segment the commutator material 12 in the circumferential direction. The positioned workpiece 11 is held by the holders 41 and 42 from both sides in the axial direction, and below the two metal saws 31 (downward in FIG. 1A) with the connecting claws 3a facing upward. Has been placed. The holders 41 and 42 hold the workpiece 11 so that it cannot move in the axial direction and cannot rotate in the circumferential direction with respect to the holders 41 and 42.

  Next, a cutting process is performed, and the dividing groove 4 is formed in the work 11. In this cutting process, first, the two metal saws 31 are rotated. Thereafter, the drive device is driven and the cutting device M is moved along one direction orthogonal to the rotation direction of the metal saw 31, thereby rotating the metal saw rotating with respect to the workpiece 11 held by the holding tools 41 and 42. 31 is moved along the axial direction of the workpiece 11 (moved from above to below in FIG. 1A). And with the movement of the metal saw 31 with respect to the workpiece | work 11, the workpiece | work 11 is cut by the two metal saws 31, and the dividing groove | channel 4 is formed in two places of a diameter direction. That is, the commutator material 12 is divided in the circumferential direction.

  Here, as shown in FIG. 7A, each blade portion 33 of the metal saw 31 has a relief portion 35 at the tip portion, so that the portion on the tip side of the relief portion 35 is the thickest in the blade portion 33. Is thinner. Furthermore, both side surfaces 33d in the thickness direction at the outer peripheral edge of the metal saw 31 are moved from the radially outer end of the metal saw 31 toward the radially inner side, that is, from the distal end of the blade 33 to the proximal end. The blade portion 33 is slightly inclined so as to approach the central portion in the thickness direction. Therefore, in the blade part 33, the part which contacts the inner surface 4a of the dividing groove 4 to be cut is a slight part such as the main cutting part 34 and the end part on the proximal end side of the blade part 33 in the escape part 35.

  In addition, each blade portion 33 of the metal saw 31 has a relief portion 35 at the distal end portion, and has a main cutting portion 34 and an auxiliary cutting portion 36 that perform cutting further toward the distal end side than the relief portion 35, and thus the blade portion 33. The width W1 of the cutting allowance 51 per tooth (the range in which dots are added in FIG. 7A) is smaller than the width W2 of the dividing groove 4 to be cut. Therefore, as shown in FIG. 7B, the width W3 of the chip 52 generated when the workpiece 11 is cut by the metal saw 31 is smaller than the width W2 of the dividing groove 4 to be cut, and the inner side surface 4a of the dividing groove 4 It is possible to be pushed out by the blade part 33 without being touched and discharged to the outside of the dividing groove 4.

  Further, a main cutting portion 34 and an auxiliary cutting portion 36 capable of cutting the workpiece 11 are formed at both ends of the blade portion 33 in the thickness direction (the same as the width direction of the dividing groove 4) of the blade portion 33. ing. That is, in each blade part 33, the auxiliary cutting part 36 which can be cut is formed also on the side where the escape part 35 opposite to the main cutting part 34 is formed. Therefore, as shown in FIG. 8A, when the joint 12c of the commutator material 12 is cut by the metal saw 31 in the workpiece 11, the chips 52 are divided into two by the joint 12c. However, cutting is performed not only in the main cutting part 34 but also in the auxiliary cutting part 36. Therefore, as shown in FIG. 8B, the chips 52 a generated on the escape portion 35 side are also sheared from the workpiece 11 by the auxiliary cutting portion 36, so that it is suppressed from remaining on the workpiece 11 as burrs.

  Then, when the metal saw 31 is moved from one end to the other end in the axial direction of the workpiece 11, the workpiece 11 passes relatively between the two metal saws 31, and two dividing grooves 4 are formed in the workpiece 11. And the cutting process ends. When the cutting process is completed, the cutting device M is moved by the driving device so that the metal saw 31 is disposed above the workpiece 11. Then, a rotation process is performed, and the holders 41 and 42 holding the workpiece 11 are rotated (360 / n) ° in the circumferential direction of the workpiece 11 (“n” is the total number of the dividing grooves 4 formed in the workpiece 11). Next, the part of the workpiece 11 where the dividing groove 4 is formed and the metal saw 31 are opposed to each other in the axial direction of the workpiece 11. That is, the workpiece 11 and the metal saw 31 are positioned.

  Then, when the cutting process and the rotation process (including the positioning process) are repeated to form eight dividing grooves 4 in the workpiece 11, eight segments 3 are formed, and the commutator 1 is completed. To do. The completed commutator 1 is released from holding by the holders 41 and 42.

As described above, the present embodiment has the following effects.
(1) The blade portion 33 provided with the relief portion 35 at the end portion on the side opposite to the side where the main cutting portion 34 is provided (the end portion on the opposite side in the thickness direction of the blade portion 33) is more than the relief portion 35. The tip side portion is thinner than the base portion side portion of the escape portion 35. Therefore, the contact area of the end portion on the side where the relief portion 35 is provided at the end portion in the thickness direction of the blade portion 33 is kept small with the inner surface 4 a of the dividing groove 4 cut in the workpiece 11. Accordingly, the friction between the workpiece 11 and the metal saw 31 can be reduced, and the generation of frictional heat is suppressed, so that the welding of the chips 52 to the inner side surface 4a of the dividing groove 4 is suppressed and the generation of burrs is suppressed. Is done. Further, the blade portion 33 having the relief portion 35 has a portion where the workpiece 11 on the tip side of the relief portion 35 is cut (that is, a portion where the main cutting portion 34 and the auxiliary cutting portion 36 are provided) of the blade portion 33. Since the thickness is thinner than the base end portion, the width W3 of the chips 52 generated when the workpiece 11 is cut is smaller than the width W2 of the dividing groove 4 to be cut. Accordingly, since the chips 52 are prevented from sliding on the inner side surface 4 a of the dividing groove 4, the chips 52 are prevented from welding to the inner side surface 4 a of the dividing groove 4 to become burrs, and the chips 52 are discharged. Improves. Further, since the auxiliary cutting portion 36 capable of cutting the workpiece 11 is provided on the tip side of the blade portion 33 with respect to the relief portion 35, the workpiece 11 can be cut even on the relief portion 35 side, and the chips 52 are not completely sheared. Remaining on the work 11 is suppressed. Therefore, the generation of burrs can be suppressed.

  (2) When the blade portion 33 is viewed from the rotation direction of the metal saw 31, the cutting side surface 33e is inclined with respect to the side surface 33d of the blade portion 33 on the side where the main cutting portion 34 is provided, and the relief portion 35 with respect to the side surface 33d. Smaller than the slope. Therefore, it is easy to ensure cutting ability in the auxiliary cutting part 36 on the opposite side to the main cutting part 34 (on the opposite side in the thickness direction of the blade part 33).

  (3) In the metal saw 31, the 20 blade portions 33 are staggered in the thickness direction of the metal saw 31 on the side having the main cutting portion 34. Therefore, when the metal saw 31 rotates, the main cutting portions 34 alternately pass through both sides in the width direction of the dividing groove 4 to be cut, so that generation of burrs can be further suppressed.

  (4) Since the segment 3 is formed by dividing the commutator material 12 in the circumferential direction by the cutting device M capable of suppressing the generation of burrs, the segments 3 adjacent to each other in the circumferential direction in the commutator 1 are caused by burrs. Short circuit is suppressed.

  (5) The angle θ2 formed between the flank 33c at the tip of the blade portion 33 and the cutting side surface 33e is formed between the flank 33c and the side surface 33d of the 33 blade portion extending from the main cutting portion 34 to the base end side of the blade portion 33. It is equal to the angle θ1. Therefore, in the blade part 33, the cutting ability of the auxiliary cutting part 36 can be made equal to the cutting ability of the main cutting part 34.

  (6) The outer peripheral edge portion including the blade portion 33 from the radially outer end of the metal saw 31 to a predetermined position on the radially inner side is formed so that the thickness is slightly reduced toward the inner side of the metal saw 31. ing. Therefore, the blade part 33 is formed so that the thickness thereof becomes thinner from the distal end toward the proximal end. Therefore, the contact area between the blade portion 33 and the inner side surface 4a of the dividing groove 4 to be cut can be further reduced, and the generation of burrs can be further suppressed.

In addition, you may change embodiment of this invention as follows.
In the above embodiment, the outer peripheral edge portion including the blade portion 33 from the radially outer end of the metal saw 31 to the predetermined position on the radially inner side becomes slightly thinner toward the inner side of the metal saw 31. Is formed. However, the thickness of the metal saw 31 may be constant even at the outer peripheral edge.

  In the above embodiment, the angle θ2 formed between the flank 33c at the tip of the blade 33 and the cutting side surface 33e is the side surface 33d of the blade 33 extending from the flank 33c and the main cutting portion 34 to the base end side of the blade 33. It is equal to the angle θ1 formed by However, the angle θ2 may be a value different from the angle θ1 as long as the cutting ability of the auxiliary cutting part 36 can be ensured.

  In the metal saw 31 of the above-described embodiment, the 20 blade portions 33 are staggered in the thickness direction of the metal saw 31 on the side having the main cutting portion 34. However, in the metal saw 31, the 20 blade portions 33 may be formed such that the side having the main cutting portion 34 is alternately replaced by a plurality in the thickness direction of the metal saw 31. Further, the end portion in the thickness direction of the blade portion 33 on the side where the main cutting portion 34 is formed may be set irregularly in the circumferential direction of the metal saw 31. Furthermore, the relief part 35 and the auxiliary cutting part 36 are not necessarily formed on all the blade parts 33.

  -The blade part 33 may be formed so that the thickness becomes thin as it goes to the back side from the front side of the rotation direction of the metal saw 31. If it does in this way, the contact area of the blade part 33 and the inner surface 4a of the dividing groove 4 to cut can further be reduced, and generation | occurrence | production of a burr | flash can be suppressed further.

  In the cutting process of the above embodiment, the metal saw 31 moves along the axial direction of the workpiece 11 by moving the cutting device M along one direction orthogonal to the rotation direction of the metal saw 31. Is done. However, the workpiece 11 may be moved along the axial direction of the workpiece 11 with respect to the metal saw 31.

  In the above embodiment, the commutator material 12 is divided into eight pieces in the circumferential direction to form eight segments 3, but the number of segments 3 formed from the commutator material 12 is not limited to eight. , May be changed as appropriate.

The cutting device M may have a configuration including only one metal saw 31.
The cutting device M may be used for cutting a workpiece other than the workpiece 11 (including cutting by cutting).

The technical idea that can be grasped from the above embodiment and each of the above modifications will be described below.
(A) In the cutting apparatus according to any one of claims 1 to 3, an angle formed by a flank at the tip of the blade portion and a cutting side surface extending from the auxiliary cutting portion toward the escaping portion is A cutting apparatus having an angle equal to an angle formed between the flank and the side surface of the blade portion extending from the main cutting portion to the base end side of the blade portion. According to this configuration, the cutting ability of the auxiliary cutting part can be made equal to the cutting ability of the main cutting part in the blade part.

  (B) In the cutting apparatus according to any one of claims 1 to 3 and (a), the blade portion is formed so that the thickness thereof decreases from the distal end toward the proximal end. The cutting device characterized by the above-mentioned. According to this configuration, the contact area between the blade portion and the inner surface of the groove to be cut can be further reduced, and the generation of burrs can be further suppressed.

  DESCRIPTION OF SYMBOLS 3 ... Segment, 11 ... Workpiece as workpiece, 12 ... Commutator material, 31 ... Metal saw, 33 ... Blade part, 33d ... Side face, 33e ... Cutting side face, 34 ... Main cutting part, 35 ... Relief part, 36 ... Auxiliary cutting part, M ... cutting device.

Claims (4)

A disk-shaped metal saw having a plurality of blades on the outer periphery is rotated, and the metal saw and the workpiece are relatively moved in one direction perpendicular to the rotation direction of the metal saw to cut the workpiece. A cutting device,
The blade portion has a main cutting portion that cuts the workpiece at one end portion in the thickness direction at the tip portion of the blade portion, and the blade portion at the other end portion in the thickness direction. An escape portion inclined so as to reduce the thickness of the blade portion toward the tip side of the blade, and an auxiliary cutting portion provided on the tip side of the blade portion with respect to the escape portion and capable of cutting the workpiece. A cutting apparatus comprising: The cutting device according to claim 1, wherein
When the blade portion is viewed from the rotation direction of the metal saw, a cutting side surface extending from the auxiliary cutting portion toward the relief portion is a side surface of the blade portion extending from the main cutting portion to the base end side of the blade portion. The cutting device characterized in that the inclination with respect to is smaller than that of the escape portion. In the cutting device according to claim 1 or 2,
The plurality of blade parts arranged in the circumferential direction have a side having a main cutting part that is staggered in the thickness direction of the metal saw. A method of dividing a commutator material that forms a plurality of segments by dividing a cylindrical commutator material made of a conductive metal material in a circumferential direction,
The metal saw and the commutator material provided in the cutting device according to any one of claims 1 to 3, wherein the metal saw has a cutting amount capable of dividing the commutator material in a circumferential direction. A positioning step for positioning to
The metal saw is rotated, and the metal saw and the commutator material are relatively moved in the axial direction of the commutator material, and the metal saw cuts the commutator material along the axial direction. A method of dividing a commutator material, characterized in that

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