JP2017104910A - Pinion cutter and gear-cutting processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower a generation rate of a product defect of a gear, and to improve processing accuracy of the gear, while suppressing increase of capital investment in a factory, and heightening productivity of gear-cutting processing.SOLUTION: A pinion cutter 56 includes a circular or ring-shaped cutter body 60, and a plurality of cutting teeth 64 provided on the outer peripheral surface of the cutter body 60 at intervals along its circumferential direction, and each having a cutting blade 64t on one end side in the axial direction. A rake angle θa of the cutting blade 64t of each cutting tooth 64 is set at a negative angle, to put it concretely, at -2 to -10 degrees.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a pinion cutter and a gear cutting method for performing gear cutting on a gear material.

  A pinion cutter is widely known as a gear cutting tool used for gear cutting on a gear material, and the configuration of a general pinion cutter is as follows.

  A general pinion cutter can be attached to and detached from a tip end portion of a main shaft of a gear cutter, and includes a circular or ring-shaped cutter body. The cutter body has a plurality of cutting teeth on the outer peripheral surface (the outer peripheral surface of the cutter main body), and the plurality of cutting teeth are equidistant along the circumferential direction (the circumferential direction of the outer peripheral surface of the cutter main body). Are lined up. Each cutter has a cutting blade on one end side (tip side) in the axial direction, and the rake angle of the cutting blade of each cutting tooth is normally set to 3 to 10 degrees with the downward direction being positive with respect to the horizontal plane. Has been.

  When gear cutting is performed on a gear material concentrically held on a turntable in a gear cutting machine using a general pinion cutter attached to the tip of the main shaft, the following is performed.

  The pinion cutter and the gear blank are rotated synchronously by rotating the main shaft around its axis (axis of the main shaft) and rotating the turntable around its axis (axis of the turntable). Then, a notch is given to the pinion cutter, the pinion cutter is reciprocated integrally with the main shaft in the axial direction, and the reciprocation of the pinion cutter is repeated. Thus, gear cutting is performed on the gear material, and external teeth or internal teeth can be created on the outer peripheral surface or inner peripheral surface of the gear material. In other words, a gear having external teeth or internal teeth can be manufactured from the gear material.

  In addition, there exist some which are shown to patent document 1-patent document 5 as a prior art relevant to this invention.

JP 2004-160645 A JP 2012-115940 A JP-A-11-58133 JP 2012-218100 A JP 2004-42179 A

  By the way, as described above, in the conventional pinion cutter, the rake angle of the cutting blade of each cutting tooth is set to a small positive angle (3 to 10 degrees), and with respect to the chips generated during the gear cutting process Thus, there is a tendency for the peeling force by the cutting blade of the cutting teeth to work (see FIG. 1B). And when the stripping force by the cutting blade of the cutting teeth is increased, the cutting surface (machined surface) of the gear material (gear) is crumpled (a trace that has been peeled into a hole), and the rate of occurrence of product defects in the gear is increased. This will increase or decrease the gear processing accuracy (product accuracy).

  On the other hand, as a technique for preventing the occurrence of stuffiness on the cutting surface of the gear material, it is known to increase the cutting speed of the pinion cutter (forward movement speed in the axial direction) or to reduce the cutting amount with respect to the pinion cutter. However, in order to increase the cutting speed of the pinion cutter, a high-performance gear cutter is required, which increases the capital investment of the factory. Moreover, if the cutting amount with respect to the pinion cutter is reduced, the time for the gear cutting process becomes longer, and the productivity of the gear cutting process is lowered.

  In other words, it is difficult to reduce the incidence of product defects in gears and improve the processing accuracy of gear tooth surfaces while suppressing the increase in plant capital investment and increasing gear cutting productivity. is there.

  The inventor of the present application, as a result of repeating trial and error trial manufacture and test in order to solve the above-mentioned problem, shows a negative angle of the cutting edge of each cutting tooth in the pinion cutter as shown in FIG. By setting the angle, the present inventors have completed the present invention by obtaining novel first knowledge that the occurrence of stuffiness on the cutting surface of the gear material can be prevented (see Examples described later). As shown in FIGS. 1 (a) and 1 (b), the first finding is that the cutting force G (FIG. 1 (b)) is generated by the cutting blade Gt of the cutting teeth G against the chips Wc generated during the gear cutting. This is probably due to the pressing force P (see FIG. 1A) on the gear material W side acting. FIG. 1A schematically shows a cutting state of the gear material W when the angling angle θa of the cutting blade Gt of the cutting tooth G is set to a negative angle as an example of the invention. As a comparative example, FIG. 1B schematically shows a cutting state of the gear material W when the scooping angle θa of the cutting blade Gt of the cutting tooth G is set to a negative angle. In the drawings, “U” indicates the upward direction (upper vertical direction), “D” indicates the downward direction (lower vertical direction), and “A” indicates the axial direction of the pinion cutter.

  Further, in addition to the first knowledge described above, the inventor of the present application can reduce the burr generated in the gear material by setting the rake angle of the cutting blade of each cutting tooth in the pinion cutter to a negative angle. A new second finding that it was possible was obtained. As shown in FIGS. 2 (a) and 2 (b), the second finding is that the tip end side of the cutting blade Gt of the cutting tooth G is the cutting end side, and the height h of the final cutting wall We of the gear material W is This is thought to be due to the small size. 2A shows the final cutting wall We of the gear material W when the angling angle θa (see FIG. 1A) of the cutting blade Gt of the cutting tooth G is set to a negative angle as an example of the invention. The cutting situation just before cutting is shown typically. FIG. 2B shows, as a comparative example, a cutting of the final cutting wall We of the gear material W when the rake angle θa (see FIG. 1B) of the cutting blade Gt of the cutting tooth G is set to a negative angle. The cutting situation just before performing is shown typically.

  A first aspect of the present invention is a pinion cutter used for gear cutting on a gear material, a circular or ring-shaped cutter main body, and an outer peripheral surface of the cutter main body in a circumferential direction thereof. A plurality of (many) cutting teeth provided at intervals along the axial direction and having cutting edges on one end side (tip side) in the axial direction. The angle is set.

  According to the first aspect of the present invention, the pinion cutter and the gear material are rotated synchronously. Then, a notch is given to the pinion cutter, and the pinion cutter is reciprocated in the axial direction relative to the gear material (forward and backward movement), and the relative reciprocation of the pinion cutter is repeated. . Thus, gear cutting is performed on the gear material, and external teeth or internal teeth can be created on the outer peripheral surface or inner peripheral surface of the gear material. In other words, a gear having external teeth or internal teeth can be manufactured from the gear material.

  Here, as described above, the rake angle of the cutting blade of each cutting tooth is set to a negative angle. Thereby, generation | occurrence | production of the blur of the cutting surface of a gear raw material can be prevented based on the above-mentioned 1st knowledge. In other words, it is possible to prevent the occurrence of burrs on the cutting surface of the gear material without increasing the cutting speed of the pinion cutter (the relative forward movement speed in the axial direction) and without reducing the cutting amount of the pinion cutter. Can do. Moreover, the burr | flash produced in a gear raw material can be made small based on the above-mentioned 2nd knowledge.

  According to a second aspect of the present invention, the pinion cutter according to the first aspect of the present invention is used, and the pinion cutter is cut in the pinion cutter while the pinion cutter and the gear material are synchronously rotated. The gear material is subjected to gear cutting by repeating the relative axial reciprocation (forward movement and backward movement).

  According to the 2nd mode of the present invention, the same operation as the 1st mode of the present invention is produced.

  According to the present invention, as described above, it is possible to prevent the occurrence of burrs on the cutting surface of the gear material without increasing the cutting speed of the pinion cutter and without reducing the cutting amount of the pinion cutter. . Therefore, according to the present invention, it is possible to reduce the incidence of product defects of the gears and improve the processing accuracy of the gears while suppressing an increase in plant capital investment and increasing the productivity of gear cutting. .

  Further, according to the present invention, as described above, burrs generated in the gear material can be reduced. Therefore, the burden of the burr removal process, which is a post process after the gear cutting, can be greatly reduced.

FIGS. 1A and 1B are schematic diagrams for explaining the first knowledge that is the premise of the present invention. FIGS. 2A and 2B are schematic diagrams for explaining the second finding that is the premise of the present invention. Drawing 3 is a mimetic diagram explaining a gearboard concerning an embodiment of the present invention. FIG. 4A is a view showing the axial movement of the pinion cutter, and FIG. 4B is a view showing the backward movement of the pinion cutter in the axial direction. Fig.5 (a) is sectional drawing explaining the pinion cutter which concerns on embodiment of this invention, FIG.5 (b) is a figure along arrow VB in Fig.5 (a). Fig.6 (a) is sectional drawing explaining the pinion cutter which concerns on the modification of embodiment of this invention, FIG.6 (b) is a figure along arrow VIB in Fig.6 (a).

  Configuration of a general gear cutting machine used for carrying out a gear cutting method according to an embodiment of the present invention, configuration of a pinion cutter according to an embodiment of the present invention, and a gear cutting processing method according to an embodiment of the present invention These will be sequentially described with reference to the drawings. In the drawings, “L” is the left direction, “R” is the right direction, “U” is the upper direction (upper vertical direction), “D” is the lower direction (lower vertical direction), and “A” is , Pinion cutter or main axis direction.

  In the specification and claims of the present application, “gear material” means a material that becomes a gear by gear cutting, and “gear” means an external gear having external teeth, an internal tooth. An internal gear having an external tooth, an external spline having an external tooth, and an internal spline having an internal tooth. “Axial direction” refers to the axial direction of the pinion cutter or cutter body, and “radial direction” refers to the radial direction of the pinion cutter or cutter body. The “circumferential direction” refers to the circumferential direction of the pinion cutter or the cutter body. “Provided” means to be provided directly, as well as indirectly provided through another member, and is synonymous with “provided”. “Providing” means to provide indirectly through another member in addition to providing directly, and is synonymous with “providing”.

  As shown in FIG. 3, the gear cutting machine 10 is a processing machine that performs gear cutting on a circular or ring-shaped gear material W (only the circular gear material W is shown) made of, for example, carbon steel for machine structure. It is. In other words, the gear cutter 10 is a processing machine that creates external teeth or internal teeth on the outer peripheral surface or inner peripheral surface of the gear material W. The gear cutting machine 10 includes a bed 12 extending in the left-right direction (one in the horizontal direction) and a column 14 standing on the bed 12.

  The bed 12 includes a slide 16 that can move in the left-right direction (one in the horizontal direction) on the upper surface (the upper surface of the bed 12). Further, the bed 12 includes a motor 18 as a slide movement actuator for moving the slide 16 in the left-right direction at an appropriate position (appropriate position of the bed 12).

  The slide 16 includes a turntable 20 on the upper side (the upper side of the slide 16), and the turntable 20 is rotatable around its axis (the axis of the turntable 20). Further, the turntable 20 has a chuck (holding portion) 22 that holds the gear material W concentrically at the center portion (the center portion of the turntable 20). The slide 16 includes a motor 24 as an actuator for rotating the table for rotating the turntable 20 at an appropriate position (appropriate position of the slide 16).

  The column 14 includes a movable frame (housing) 26 on the right side (the right side of the column 14), and the movable frame 26 can be adjusted in the vertical direction. Further, the column 14 is provided with a motor 28 as a movable frame position adjusting actuator for adjusting the movable frame 26 in the vertical direction at an appropriate position (appropriate position of the column 14).

  The movable frame 26 includes a hollow (tubular) processing head 30 at an appropriate position (appropriate position of the movable frame 26) via a swing shaft (mounting shaft) 32. It can be swung in the left-right direction (horizontal direction) around the swing shaft 32 (the axis of the swing shaft 32). Further, the machining head 30 includes a support cylinder 34 in its interior (inside the machining head 30) via a bearing 36, and the support cylinder 34 is arranged around its axis (axis of the support cylinder 34). It can be rotated. Further, the support cylinder 34 is provided with a main shaft 38 concentrically extending in the vertical direction on the inner side (inside the support cylinder 34). The main shaft 38 is movable in the axial direction (the axial direction of the main shaft 38) with respect to the support tube 34. The main shaft 38 rotates integrally with the support cylinder 34 via a key (not shown) or the like.

  The support cylinder 34 is integrally provided with a worm wheel 40 on the outer peripheral part thereof (the outer peripheral part of the support cylinder 34), and the processing head 30 is provided with a worm 42 meshed with the worm wheel 40 therein. . The machining head 30 includes a motor 44 as a spindle rotation actuator for rotating the spindle 38 integrally with the support cylinder 34 at an appropriate position (appropriate position of the machining head 30). An output shaft (not shown) of the motor 44 is interlocked with the worm 42.

  The movable frame 26 includes a crankshaft 46 extending in the horizontal direction above the machining head 30. The crankshaft 46 has an eccentric portion (crank pin) 48 that is rotatable about its axis (the axis of the crankshaft 46) and is eccentric with respect to the axis. The eccentric portion 48 of the crankshaft 46 is swingably (rotatably) connected to the upper end portion of the connecting rod 50, and the lower end portion of the connecting rod 50 is connected to the upper end portion of the main shaft 38 via a spherical bearing 52. Are swingably connected. The movable frame 26 includes a motor 54 as a crankshaft rotating actuator for rotating the crankshaft 46 at an appropriate position. In other words, the movable frame 26 includes, at an appropriate position, a motor 54 as a main shaft reciprocating actuator for reciprocating the main shaft 38 in the axial direction via the crank shaft 46 and the like. An output shaft (not shown) of the motor 54 is linked and connected to the crankshaft 46 via a connecting belt (not shown). Further, the movable frame 26 includes a cam mechanism (not shown) on the left side of the processing head 30 for intermittently swinging the processing head 30 in the left-right direction in conjunction with the rotation of the crankshaft 46.

  The main shaft 38 has a pinion cutter 56 as a gear cutting tool detachably attached to a lower end portion thereof (lower end portion of the main shaft 38) via a fixture (mounting bolt) 58, and the pinion cutter 56 is attached to the main shaft 38. Are located concentrically. Further, the pinion cutter 56 is configured to be in a machining posture when the machining head 30 is intermittently swung in the left-right direction and to be in an interference avoidance posture when the axial head is moved backward. The processing posture refers to a posture for performing gear cutting on the gear material W as shown in FIG. The interference avoidance posture refers to a posture for avoiding interference with the gear material W as shown in FIG.

  Next, details of the configuration of the pinion cutter 56 according to the embodiment of the present invention will be described.

  As shown in FIGS. 5 (a) and 5 (b), a pinion cutter 56 according to an embodiment of the present invention is a gear cutting tool used to perform gear cutting on a gear material made of carbon steel for machine structure, for example. It is one of. Further, the pinion cutter 56 is made of high-speed steel (high-speed tool steel) or cemented carbide, and can be detachably attached to the lower end portion (the tip portion in the axial direction) of the main shaft 38 via the attachment tool 58 as described above. It has become.

  The pinion cutter 56 includes a circular cutter body 60, and the cutter body 60 has an insertion hole 62 through which a part of the fixture 58 is inserted into the center (the center of the cutter body 60). Have. Note that the cutter body 60 may have a ring shape instead of a circular shape.

  The cutter body 60 includes a plurality of cutting teeth 64 having, for example, an involute tooth shape on an outer peripheral surface thereof (an outer peripheral surface of the cutter main body 60). The plurality of cutting teeth 64 are arranged in the circumferential direction (the circumferential direction of the outer peripheral surface of the cutter main body). ) Are evenly spaced. Each cutting tooth 64 has a cutting edge 64t on one end side (tip side) in the axial direction.

  The scooping angle θa of the cutting blade 64t of each cutting tooth 64 is set to a negative angle. Specifically, the angle θa of the cutting edge 64t of each cutting tooth 64 is set to −2 to −10 degrees, preferably −3 to −5 degrees. The reason why the crease angle θa of the cutting blade 64t of each cutting tooth 64 is set to be equal to or larger than the absolute value of −2 degrees is less than the absolute value of −2 degrees with respect to chips generated during the gear cutting process. This is because the pressing force P (see FIG. 1A) to the gear material W side by the cutting blade 64t of the tooth 64 does not work sufficiently. The reason why the rake angle θa of the cutting blade 64t of each cutting tooth 64 is made equal to or less than the absolute value of −10 degrees is that when the absolute value of −10 degrees is exceeded, the cutting resistance of the cutting blade 64t of the cutting teeth 64 becomes excessive. This is because it becomes difficult to suppress the shake (vibration) of the pinion cutter 56.

  The clearance angle θb of the cutting blade 64t of the cutting tooth 64 is set to 3.5 to 6.5 degrees, preferably 4 to 5 degrees. The reason why the clearance angle θb of the cutting blade 64t of each cutting tooth 64 is 3.5 degrees or more is that the clearance surface 64f of the cutting teeth 64 interferes with (contacts with) the cutting surface of the gear material W when it is less than 3.5 degrees. This is because it is easy to. The reason why the clearance angle θb of the cutting blade 64t of each cutting tooth 64 is set to 6.5 degrees or less is that when it exceeds 6.5 degrees, initial wear due to overload tends to occur at the tip of the cutting blade 64t of the cutting tooth 64. Because.

  Instead of each cutting tooth 64 having a cutting edge 64t, as shown in FIGS. 6 (a) and 6 (b), a hard tip 66 including a cutting edge 66t and made of carbide may be provided. In this case, the portion other than the hard tip 66 in the pinion cutter 56 is made of high-speed steel. For the same reason as described above, the angle θa of the cutting edge 66t of each hard tip 66 is set to −2 to −10 degrees, preferably −3 to −5 degrees. The clearance angle θb of the cutting blade 66t of each hard tip 66 is set to 3.5 to 6.5 degrees, preferably 4 to 5 degrees. The flank 66 f of each hard tip 66 is the flank of each cutting tooth 64.

  Next, the gear cutting method according to the embodiment of the present invention will be described including the operation of the embodiment of the present invention.

  The circular gear material W is concentrically held on the turntable 20 by the chuck 22. Then, by moving the slide 16 in the left-right direction by driving the motor 24, the gear material W is moved in the left-right direction integrally with the slide 16 and the turntable 20 to approach the pinion cutter 56. Further, the pinion cutter 56 is positioned at a slightly higher height than the gear material W by adjusting the position of the movable frame 26 in the vertical direction by driving the motor 28. Thereby, the pinion cutter 56 can be positioned relative to the gear material W at a predetermined processing start position. The predetermined processing start position refers to a predetermined position for starting gear cutting for the gear material W.

  After the pinion cutter 56 is positioned at a predetermined machining start position, the main shaft 38 is rotated by driving the motor 44 and the turntable 20 is rotated by driving the motor 24, whereby the pinion cutter 56 and the gear material W are rotated synchronously. . Next, the drive of the motor 24 is controlled to adjust the amount of movement (moving speed) of the slide 16 in the left direction so that the pinion cutter 56 is slightly moved in the right direction relative to the gear material W. The pinion cutter 56 is cut in the radial direction. In addition, the drive of the motor 44 is controlled to adjust the rotational speed (circumferential speed) of the main shaft 38, thereby giving the pinion cutter 56 a circumferential cut. Then, by driving the motor 54, the main shaft 38 is reciprocated in the axial direction via the crankshaft 46 or the like. Then, combined with the action of the cam mechanism, the pinion cutter 56 is moved forward in the axial direction in the machining posture and moved backward in the axial direction in the interference avoidance posture. Furthermore, the reciprocating motion of the pinion cutter 56 is repeated by driving the motor 54. Thereby, gear cutting is performed on the circular gear material W, and external teeth can be created on the outer peripheral surface of the gear material W. In other words, a gear having external teeth can be manufactured from the gear material W.

  Note that gear cutting can be performed on the ring-shaped gear material W to create internal teeth on the inner peripheral surface of the gear material W in the same manner as described above. When manufacturing a helical gear, the pinion cutter 56 is rotated by a combination of a synchronous rotation with respect to the gear material W and a rotation corresponding to the torsion angle of the gear material W.

  Here, as described above, the scooping angle θa of the cutting blade 64t (72) of each cutting tooth 64 is set to a negative angle. Thereby, generation | occurrence | production of the whip of the cutting surface of the gear raw material W can be prevented based on the above-mentioned 1st knowledge. In other words, the cutting speed of the pinion cutter 56 (in other words, the moving speed in the axial direction of the pinion cutter 56) is not increased, or the cutting amount (the cutting amount in the radial direction or the circumferential direction) of the pinion cutter 56 is reduced. In addition, it is possible to prevent the occurrence of stuffiness on the cutting surface of the gear material W.

  In particular, the angle θa of the cutting blade 64t (66t) of each cutting tooth 64 is set to -2 to -10 degrees. Thereby, the gear material W side by the cutting blade 64t of the cutting tooth 64 against the chips generated during the gear cutting while suppressing the cutting resistance of the cutting blade 64t (66t) of the cutting tooth 64 from becoming excessive. The pressing force P is sufficiently exerted on the gear material W, so that the occurrence of burrs on the cutting surface of the gear material W can be reliably prevented.

  Moreover, since the scooping angle θa of the cutting blade 64t (72) of each cutting tooth 64 is set to a negative angle, the burr generated in the gear material W can be reduced based on the second knowledge described above. .

  As described above, according to the embodiment of the present invention, as described above, the cutting surface of the gear material W can be cut without increasing the cutting speed of the pinion cutter 56 or reducing the cutting amount of the pinion cutter 56. Occurrence can be reliably prevented. Therefore, according to the embodiment of the present invention, it is possible to reduce the incidence of product defects in gears and improve the processing accuracy of gears while suppressing an increase in plant capital investment and increasing the productivity of gear cutting. it can.

  Moreover, according to the embodiment of the present invention, burrs generated in the gear material W can be reduced. Therefore, the burden of the burr removal process, which is a post process after the gear cutting, can be greatly reduced.

  In addition, this invention is not restricted to description of the above-mentioned embodiment, It can implement in a various aspect by making an appropriate change. Further, the scope of rights encompassed by the present invention is not limited to the above-described embodiment.

(Example of the present invention)
A pinion cutter 56 in which the rake angle θa of the cutting blade 64t of the cutting tooth 64 is set to a negative angle (−3 degrees) was prototyped as an invention. A pinion cutter different from the pinion cutter 56 only as a comparative product was used in that the scooping angle θa of the cutting blade 64t of the cutting tooth 64 was set to a positive angle (+3 degrees). The invention ratio and the comparative product were subjected to a gear cutting test under severer cutting conditions (cutting conditions in which musiness was likely to occur) than normal cutting conditions. As a result, in the case of gear cutting with a comparative product, murmur was confirmed on the cutting surface of the gear material, whereas in the case of gear cutting with the inventive product, murky was confirmed on the cutting surface of the gear material. Was not. Further, it was confirmed that the burrs generated in the gear material can be significantly reduced in the case of the gear cutting by the inventive product compared to the case of the gear cutting by the comparative product.

W Gear material Wc Chip We Final cutting wall θa Creeping angle θb Clearance angle G Cutting tooth Gt Cutting blade F Stripping force P Pushing force to gear material side 10 Grinder 12 Bed 14 Column 16 Slide 18 Motor 20 Turntable 22 Chuck 26 Movable frame 30 Processing head 32 Oscillating shaft 34 Support cylinder 38 Main shaft 40 Worm wheel 42 Worm 46 Crank shaft 48 Eccentric portion 50 Connecting rod 52 Spherical bearing 54 Motor 56 Pinion cutter 60 Cutter body 62 Insertion hole 64 Cutting teeth 64t Cutting blade 66 Hard tip 66t Cutting blade

Claims (3)

A pinion cutter used for gear cutting on a gear material,
A circular or ring cutter body;
A plurality of cutting teeth provided on the outer peripheral surface of the cutter body at intervals along the circumferential direction thereof, and having cutting edges on one end side in the axial direction;
A pinion cutter in which the cutting angle of each cutting tooth is set to a negative angle.   The pinion cutter according to claim 1, wherein the cutting angle of each cutting tooth is set to −2 to −10 degrees. Using the pinion cutter according to claim 1 or claim 2,
While the pinion cutter and the gear material are rotated synchronously, the pinion cutter is cut, and the pinion cutter is repeatedly reciprocated in the axial direction relative to the gear material, thereby performing gear cutting on the gear material. The gear cutting method to perform.

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