JP2021013988A - Grinding processing method using grindstone - Google Patents

Abstract

To provide a processing method which is low-cost and enables a service life of a tool to be lengthened.SOLUTION: A processing method using a grindstone comprises: an arranging step in which a grindstone 20 is arranged at a processing initial position at which the grindstone 20 is inclined so that a center axis line of the grindstone 20 and a center axis line of a work-piece W have a predetermined crossing angle and further a rear end part 23b of the grindstone 20 is opposed to the work-piece W in a state where the grindstone 20 is moved along a circumferential direction of the work-piece W to be offset to have an offset angle; and a grinding processing step in which grinding processing is applied to a part Ww to be processed in the work-piece W by moving the grindstone 20 arranged at the processing initial position in the arranging step so that the grindstone 20 moves relatively to the work-piece W, from the rear end part toward a front end part, while synchronously-rotating the work-piece W and the grindstone 20.SELECTED DRAWING: Figure 9

Description

The present invention relates to a grinding method using a grindstone.

Conventionally, for example, a barrel-shaped screw-shaped tool for processing internal gears (hereinafter, referred to as "conventional tool") disclosed in Japanese Patent No. 5222125 is known. This conventional tool is a grindstone, and is adapted to grind a workpiece by engaging with the workpiece in a state where an intersection angle is given to the workpiece during machining. For this reason, the grindstone is formed in a barrel shape and a grindstone tooth in a screw shape so that the diameter gradually decreases from the intermediate portion in the axial direction toward both ends in the axial direction.

Japanese Patent No. 5222125

By the way, in the above-mentioned conventional tool, since it is necessary to avoid interference with the workpiece portion of the workpiece during machining, the grindstone forms barrel-shaped or screw-shaped teeth according to the machining state of the workpiece. There is a need. As a result, it is necessary to manufacture or adjust the grindstone according to the processing state of the workpiece, which may increase the manufacturing cost of the grindstone.

Here, in order to reduce the manufacturing cost of the grindstone, it is conceivable to use an inexpensive grindstone having a simple shape. However, when a grindstone with a simple shape is used, there is a possibility that unnecessary interference may occur with the workpiece on the workpiece on the end side of the grindstone that first contacts the workpiece in the grinding process. The amount of processing on the end side that comes into contact first increases. As a result, there is a problem that the life of the grindstone is shortened.

An object of the present invention is to provide a grinding method using a grindstone capable of extending the life of an inexpensive grindstone.

The grinding method using a grindstone according to the present invention is rotationally driven via a shaft member coaxially connected to the spindle of the machine tool and is relative to the annular work piece in the direction of the central axis of the work piece. Grinding a groove-shaped workpiece created in a rotationally driven workpiece using a grindstone that moves forward and backward and has one or more ridges that have components in the direction of the central axis. This is a grinding method using a grindstone, in which the outer peripheral surface is configured as a grinding part, and the front end portion opposite to the rear end portion in the direction of the central axis from the rear end portion on the shaft member side. It is formed so as to have a cylindrical outer contact surface having the same diameter in the range up to, and the central axis of the grindstone and the central axis of the workpiece intersect with each other in order to bring the ground portion of the machined part into contact with the part to be machined. The grindstone is tilted so as to have an angle, and the grindstone is moved along the circumferential direction of the workpiece to be offset so as to have an offset angle. Furthermore, the workpiece is the main shaft of the machined portion rather than the ground portion. The process of arranging the workpiece and grindstone at the initial machining position on the side and the grindstone placed at the initial machining position are moved backward relative to the workpiece while the workpiece and grindstone are rotated in synchronization. It is provided with a grinding process in which the processed portion is brought into contact with the workpiece to be ground and the workpiece is ground.

According to this, in a state where the grindstone is tilted and offset along the circumferential direction of the workpiece, the tool is further arranged at the initial machining position where the rear end of the cylindrical grinding part of the grindstone faces the workpiece. Can be done. Then, in a state where the workpiece and the grindstone are rotated in synchronization, the grindstone is moved relative to the workpiece from the rear end to the front end to grind the workpiece to be machined. be able to.

As a result, by starting the grinding process from the initial machining position offset in the circumferential direction of the workpiece, unnecessary interference between the grindstone and the workpiece during the grinding process can be avoided even when a grindstone with a simple shape is used. can do. Therefore, it is not necessary to manufacture a grindstone having a complicated shape according to the workpiece portion of the workpiece, and the manufacturing cost of the grindstone can be reduced. Further, the ground portion can be gradually brought into contact with the workpiece from the rear end portion to the front end portion. As a result, it is possible to prevent significant wear from occurring only in a part of the ground portion of the grindstone, so that the life of the grindstone can be extended.

It is a schematic plan view which shows the structure of the gear grinding machine schematicly. It is the schematic perspective view which shows the structure of the internal gear schematicly. It is a top view for demonstrating the reference position of a grindstone and a work piece. It is a rear view of FIG. 3A. It is a top view for demonstrating the intersection angle between a grindstone and a work piece. It is a rear view of FIG. 4A. It is a top view for demonstrating the processing initial position of a grindstone and a work piece. It is a rear view of FIG. 5A. It is a top view for demonstrating the end state of grinding. It is a rear view of FIG. 6A. It is a figure for demonstrating the structure of the grindstone. It is a figure for demonstrating the structure of another example of a grindstone. It is a flowchart for demonstrating the grinding process. 5B is a cross-sectional view taken along the line HH of FIG. 5B for explaining a state of grinding. It is a figure for demonstrating the state of the grinding process by a comparative example.

(1. Outline of grinding method using a grindstone)
Hereinafter, the cutting method using the grindstone of the present invention will be described with reference to FIGS. 1 to 11. The grinding method using a grindstone of the present invention is rotationally driven via an arbor 21 which is a shaft member coaxially connected to a tool spindle 11 of a gear grinding machine 10 which is a machine tool, and is driven by rotation with respect to an annular workpiece W. A grindstone having a grindstone tooth portion 23 which is a machined portion of one or more ridges capable of moving forward and backward relative to the direction of the central axis Cw of the workpiece W and having a component in the direction of the central axis Ct. 20 is used to grind the groove-shaped workpiece Ww created in the rotationally driven machine tool W.

As a machine tool to be applied in the grinding method using the grindstone of the present invention, the gear grinding machine 10 can utilize a machining center capable of skiving offset machining when manufacturing internal gears and external gears which are annular workpieces. it can. Further, in the annular workpiece W to be applied in the grinding method using the grindstone of the present invention, the groove-shaped workpiece Ww is created on at least one of the inner peripheral surface and the outer peripheral surface, and as an example. Examples thereof include an internal gear in which an internal tooth has a groove shape of a workpiece and an external gear in which an external tooth is created. In the case of an internal gear or an external gear, the groove shape may have a spline groove, a spiral tooth groove, and a torsion angle groove as long as it has a component in the direction of the central axis Cw of the workpiece W. ..

Further, the grindstone 20 in the grindstone grinding method of the present invention includes a grindstone tooth 23a which is one or more ridges constituting the grindstone tooth portion 23. The grindstone teeth 23a are, for example, a tooth tip portion 23d which is an outer peripheral surface and a tooth tip surface, a tooth side portion 23e which is a tooth surface provided on both sides in the rotation direction with respect to the tooth tip portion 23d, and a tooth bottom surface. It is composed of a tooth bottom portion 23f, a rear end portion 23b which is an end surface on the arbor 21 side, and a front end portion 23c which is an end surface opposite to the arbor 21 in the direction of the central axis. The grindstone teeth 23a have a twist angle α inclined with respect to the central axis Ct of the grindstone 20. The tooth side portion 23e is a workpiece Ww of the workpiece W, and is, for example, a grinding portion for grinding the tooth surface We excluding the tooth tip and the tooth bottom in the tooth of the gear. Here, the grindstone tooth portion 23 (tooth side portion 23e) is formed so as to have a cylindrical circumscribed surface having the same diameter from the rear end portion 23b to the front end portion 23c.

Here, the grindstone 20 includes a grindstone tooth portion 23 on the peripheral surface of a grindstone main body 22 having a simple cylindrical or cylindrical shape having the same diameter from the rear end portion 23b to the front end portion 23c. Can be mentioned. Further, as the grindstone 20, an electrodeposition tool in which abrasive grains are electrodeposited on the tooth surface formed on the grindstone main body 22 of a metal such as iron or aluminum, particularly on the tooth side portion 23e, can be used.

Then, in the grinding method using the grindstone of the present invention, in the arrangement process, the tooth side portion 23e of the grindstone tooth 23a and the workpiece W (tooth surface We) of the workpiece W are processed according to the twist angle α of the grindstone tooth 23a. In order to secure a clearance angle between the grindstone 20 and the grindstone 20, the grindstone 20 is tilted so that the central axis Ct of the grindstone 20 and the central axis Cw of the workpiece W have a predetermined crossing angle θ. In addition, there is a tooth of the workpiece W with which the grindstone tooth 23a is in contact, and in FIG. 5B, the tooth to the right of this tooth needs to be released downward when viewed from the grindstone tooth 23a. The grindstone 20 and the workpiece W are made to face each other in the direction of the Z-axis, and the grindstone 20 is offset so as to have an offset angle φ as if the grindstone 20 was moved along the circumferential direction of the workpiece W. Further, the workpiece W and the grindstone 20 are arranged at the initial machining positions where the workpiece W corresponds to the tooth tip portion 23d on the tool spindle 11 side. Therefore, as an example, when the workpiece is an internal gear, the grindstone 20 is arranged so that the arbor 21 passes through the internal gear when viewed with reference to the tool spindle 11 of the gear grinding machine 10.

Then, in the grinding method using the grindstone of the present invention, in the grinding process, after the workpiece W and the grindstone 20 are placed at the initial machining positions, the workpiece W and the grindstone 20 are placed on the grindstone teeth 23a and the grindstone W of the grindstone 20. The grindstone 20 arranged at the initial position of machining is moved backward relatively toward the workpiece W in a state of being rotated in synchronization with the workpiece Ww (tooth surface We) so as to mesh with each other. The tooth side portion 23e is brought into contact with the workpiece Ww (tooth surface We) from the rear end portion 23b side at the front end portion 23c, and the workpiece Ww (tooth surface We) is ground. In this case, since the grinding process is performed from the initial processing position, the processing path in the grinding method using the grindstone of the present invention is, for example, opposite to the well-known processing path for skiving offset processing that advances a tool or the like.

By rotating the turntable 12b around the A axis, the grindstone 20 has an intersection angle θ with respect to the workpiece W (tooth surface We) of the workpiece W. Further, by moving the grindstone 20 and the workpiece W relative to each other in the X-axis, Y-axis and Z-axis directions as if the grindstone 20 was moved along the circumferential direction of the workpiece W, the grindstone 20 is moved by the workpiece W. It has an offset angle φ with respect to.

Here, the offset angle φ is set from the rear end portion 23b side of the tooth side portion 23e in contact with the workpiece Ww when the workpiece Ww is created on the inner peripheral surface of the workpiece W. The length of the first perpendicular line D1 extending to the central axis Cw of the workpiece is the second perpendicular line D2 extending from the front end 23c side of the tooth side portion 23e in contact with the workpiece Ww to the central axis Cw of the workpiece W. Is determined to be less than the length of. On the other hand, when the workpiece Ww is created on the outer peripheral surface of the workpiece W, the length of the first perpendicular line D1 is determined to be larger than the length of the second perpendicular line D2.

As described above, since the grindstone 20 has the intersection angle θ and the offset angle φ, the cross-sectional shape of the tooth surface We of the workpiece W can be optimized, and the workpiece W with which the grindstone teeth 23a are in contact can be optimized. The tooth to the right of the tooth can be released downward when viewed from the grindstone tooth 23a in FIG. 5B. That is, when the grindstone 20 is moved relative to the workpiece W, in the grindstone 20, first, the front end portion 23c side is in contact with the tooth surface We in contact with the workpiece Ww (tooth surface We). Become. Here, in the grinding process, when the tooth side portion 23e is brought into contact with the workpiece Ww (tooth surface We), the axial end surface of the rear end portion 23b does not come into contact with the workpiece Ww (tooth surface We).

As a result, the progress of local wear on the grindstone tooth portion 23, that is, the tooth side portion 23e is prevented. Even if the grindstone 20 has a simple shape such as a columnar shape or a cylindrical shape, the grindstone tooth portion 23 (tooth side portion 23e) of the grindstone 20 and the workpiece Ww (tooth surface We) of the workpiece W are unnecessary. Grinding can be performed by preventing interference. Therefore, it is possible to reduce the manufacturing cost associated with the manufacturing of the grindstone 20, and it is possible to extend the life of the grindstone 20.

(2. Configuration of gear grinding machine 10)
The gear grinding machine 10 will be described with reference to the drawings. As shown in FIG. 1, the gear grinding machine 10 moves, for example, in three orthogonal axes (X-axis, Y-axis, Z-axis) and C-axis (center axis Cw of the workpiece W and center axis Ct of the grindstone 20). It is a five-axis machining center that can rotate around and around the A axis. As shown in FIG. 2, the gear grinding machine 10 grinds the tooth surface We, which is the workpiece Ww, on the inner peripheral surface of the workpiece W, which is an internal gear, with a grindstone 20.

The gear grinding machine 10 includes a tool-side spindle device M, a workpiece-side spindle device N, and a control device 15 for controlling the operation of grinding. Although not shown, the gear grinding machine 10 can be provided with a tool magazine capable of accommodating a plurality of tools, a grindstone changing device for exchanging a plurality of types of grindstones 20, and the like.

The tool-side spindle device M includes a tool spindle 11 that supports and rotates the grindstone 20. The tool spindle 11 is rotatably supported around the central axis Ct of the grindstone 20 via the chuck 11a. Further, the tool-side spindle device M is movably supported in the Z-axis direction by a column 13 that can move in the Y-axis direction on a bed (not shown). Therefore, the grindstone 20 can rotate around the central axis Ct and can move in the Y-axis direction and the Z-axis direction with respect to the bed.

The workpiece-side spindle device N includes a workpiece spindle 12 that supports and rotates the workpiece W and can move relative to the tool spindle 11. The work spindle 12 rotatably supports the work W around the C axis, that is, around the central axis Cw of the work W via the holder 12a. Further, the workpiece-side spindle device N moves the turntable 12b that rotatably (tilts) the workpiece spindle 12 around the A axis and the turntable 12b on the bed in the X-axis direction. It is provided with an X-axis table 14 that supports the above. Therefore, the workpiece W can rotate around the central axis Cw of the workpiece W, can rotate around the A axis with respect to the bed, and can move relative to the X-axis direction, that is, the grindstone 20.

The control device 15 drives and controls a ball screw mechanism (not shown) for moving the tool spindle 11 and a drive motor (provided in the column 13) to drive the grindstone 20 supported by the tool spindle 11 in the Y-axis direction and. Move in the Z-axis direction. Further, the control device 15 controls a drive motor (provided in the tool-side spindle device M) for rotation of the tool spindle 11 (provided in the tool-side spindle device M), and uses the grindstone 20 supported by the tool spindle 11 as the center axis Ct. Rotate it around.

Further, the control device 15 drives and controls a ball screw mechanism (not shown) and a drive motor (provided on the X-axis table 14) for moving the work spindle 12, and is supported by the work spindle 12. The object W is moved in the X-axis direction. Further, the control device 15 controls a drive motor (provided in the workpiece side spindle device N) for rotation of the workpiece spindle 12 (provided in the workpiece side spindle device N) to control the workpiece W supported by the workpiece spindle 12. Rotate around the central axis Cw. Further, the control device 15 drives and controls the drive motor for the turntable 12b to rotate the workpiece W supported by the turntable 12b around the A axis.

Instead of rotating the workpiece W around the A axis relative to the tool spindle 11, that is, the grindstone 20, the grindstone 20 is configured to rotate around the A axis with respect to the workpiece W. It is also possible. In this case, the tool spindle 11 is configured to be supported by the turntable.

Then, when grinding the workpiece W, the control device 15 is supported by the central axis Ct of the grindstone 20 supported by the tool spindle 11 and the workpiece spindle 12, as shown in FIGS. 3A and 3B. The central axis Cw of the workpiece W is set to a parallel position (reference position). In the following description, the plane passing through the central axis Ct and the central axis Cw is referred to as the reference plane BP.

Further, the control device 15 arranges the grindstone 20 so that the workpiece W is closer to the tool spindle 11 than the grindstone 20. Then, the control device 15 drives and controls the drive motor for the turntable 12b to rotate the workpiece W supported by the turntable 12b around the A axis. As a result, as shown in FIGS. 4A and 4B, the control device 15 inclines the central axis Ct of the grindstone 20 supported by the tool spindle 11 in the direction perpendicular to the reference plane BP by the intersection angle θ. This intersection angle θ is adjusted based on the twist angle α of the tooth surface We of the internal gear which is the workpiece W, and the tooth side portion 23e which is the grinding portion of the grindstone 20 and the tooth surface We of the workpiece W It is decided to secure a clearance angle between them.

Further, as shown in FIGS. 5A and 5B, the control device 15 shifts the grindstone 20 from the reference position on the reference plane BP by an offset angle φ in the circumferential direction of the workpiece W while having the intersection angle θ. The workpiece W and the grindstone 20 are arranged at the initial processing positions. Here, the offset angle φ of the grindstone 20 is determined so that the tooth to the right of the tooth of the workpiece W in contact with the grindstone tooth 23a in FIG. 5B is released downward when viewed from the grindstone tooth 23a.

Then, the control device 15 moves the grindstone 20 backward from the initial machining position to the machining end position shown in FIGS. 6A and 6B relative to the direction of the central axis Cw of the workpiece W to grind the workpiece W. That is, in the grinding process using a grindstone, the processing path is opposite to the skiving process for advancing a tool or the like, which is usually widely performed.

Specifically, the control device 15 drives and controls the drive motor for rotating the tool spindle 11 with the grindstone 20 arranged at the initial machining position. Then, the control device 15 rotates the grindstone 20 supported by the tool spindle 11 around the central axis Ct. Further, the control device 15 drives and controls a drive motor for rotating the workpiece spindle 12 to rotate the workpiece W supported by the workpiece spindle 12 around the central axis Cw. At this time, the control device 15 is a drive motor for each rotation of the tool spindle 11 and the workpiece spindle 12 so that the grindstone teeth 23a of the grindstone 20 and the tooth surface We of the workpiece W mesh with each other and rotate in synchronization. Drive control.

Then, the control device 15 drives and controls the ball screw mechanism and the drive motor for each movement of the tool spindle 11 and the workpiece spindle 12. As a result, the control device 15 moves the grindstone 20 supported by the tool spindle 11 relative to the workpiece W supported by the workpiece spindle 12. Then, as shown in FIGS. 5A and 5B, the control device 15 arranges the grindstone 20 at the initial processing position where the processing point Pc is realized, and controls the grinding (finishing) of the tooth surface We of the workpiece W. Do.

(3. Composition of grindstone 20)
As shown in FIG. 7, the grindstone 20 includes an arbor 21 as a shaft member, a columnar grindstone main body 22, and a grindstone tooth portion 23. The arbor 21 is supported by the tool spindle 11 of the gear grinding machine 10 via the chuck 11a. The grindstone main body 22 is formed in a columnar shape using a grindstone, and is fixed to the tip end side of the arbor 21, that is, the side opposite to the proximal end side supported by the chuck 11a.

The grindstone tooth portion 23 as a processed portion has a plurality of ridged grindstone teeth 23a formed by grooves extending integrally with the grindstone main body 22 along the central axis Ct on the outer peripheral surface side of the grindstone main body 22. ing. Here, the grindstone teeth 23a in the grindstone tooth portion 23 have a shape formed linearly along the central axis Ct, as shown in FIG. 7, based on, for example, the shape of the tooth surface We of the workpiece W. .. As for the shape of the grindstone teeth 23a, as shown in FIG. 8, if the tooth surface We of the workpiece W does not have a twist angle α, it will have a twist angle.

As shown in FIGS. 7 and 8, the grindstone teeth 23a have a rear end portion 23b which is an end surface on the arbor 21 side and a front end portion 23c which is an end surface opposite to the arbor 21 in the direction of the central axis Ct. I have. The grindstone teeth 23a are provided between the rear end portion 23b and the front end portion 23c on both sides in the rotational direction with respect to the tooth tip portion 23d, which is the outer peripheral surface and the tooth tip surface, and the tooth tip portion 23d. It includes a tooth side portion 23e which is a tooth surface and a tooth bottom portion 23f which is a tooth bottom surface. Here, the outer peripheral surface of the tooth side portion 23e is configured as a grinding portion. The grindstone tooth portion 23 (tooth side portion 23e) is formed so as to have a cylindrical circumscribed surface having the same diameter from the rear end portion 23b to the front end portion 23c.

In the grinding method using a grindstone, the grindstone 20 is arranged at the initial machining position having an offset angle φ to perform the grinding process. As described above, since the grindstone 20 has an offset angle φ with respect to the workpiece W, the tooth side portion 23e of the grindstone tooth portion 23, which is a machining portion, is forward with respect to the tooth surface We of the workpiece W in the grinding process. On the end 23c side, contact can be made while gradually increasing the notch from the rear end 23b side toward the front end 23c side. Further, it is possible to avoid unnecessary interference with the tooth on the right side (see FIG. 5B) of the tooth of the workpiece W in contact with the tooth side portion 23e of the grindstone tooth portion 23. Therefore, the grindstone 20 can be configured to have the grindstone tooth portion 23 on the peripheral surface of the cylindrical grindstone main body 22 having a simple shape.

As a result, when the grindstone 20 is manufactured, for example, the grindstone body 22 and the grindstone teeth are prevented from interfering with each other for each shape of the tooth surface We, which is the workpiece W to be processed, as in the conventional grindstone described above. It is not necessary to change the shape of the portion 23 (grinding stone tooth 23a). Therefore, the versatility of the grindstone 20 can be increased, and as a result, the manufacturing cost can be reduced.

Here, moving the grindstone 20 together with the arbor 21 toward the tool spindle 11, that is, moving the rear end portion 23b of the grindstone tooth portion 23 relatively toward the workpiece W is called "reverse". To do. Further, the grindstone 20 is moved integrally with the arbor 21 so as to be separated from the tool spindle 11, that is, the front end portion 23c of the grindstone tooth portion 23 is relatively directed toward the workpiece W or passed through the workpiece W. Moving is called "advancing".

It is also possible to use an electrodeposition tool as the grindstone 20. In this case, for example, the grindstone body 22 is formed from a cemented carbide so as to have the grindstone tooth portions 23. Then, the abrasive grains are electrodeposited on each of the grindstone teeth 23a of the grindstone tooth portion 23, particularly the tooth side portion 23e, to manufacture an electrodeposition tool. Even when an electrodeposition tool is used, the tooth surface We of the workpiece W can be ground.

(4. Details of grinding method using a grindstone)
Next, the details of the grinding method will be described with reference to the “machining program” of FIG. 9 executed by the control device 15. The workpiece W, which is created by the skiving processing method, which is one of the gear processing methods, in which the tooth surface We (internal teeth) of the internal gear is formed as the workpiece Ww on the cylindrical member, is rotationally driven on the workpiece spindle 12. It shall be supported as much as possible.

The control device 15 starts the execution of the grinding process program in step S10. Subsequently, the control device 15 arranges the grindstone 20 at the initial processing position in step S11 (arrangement step). Specifically, as shown in FIGS. 3A and 3B, the control device 15 sets the grindstone 20 and the workpiece W as reference positions. Then, as shown in FIGS. 4A and 4B, the control device 15 advances the grindstone 20 from the reference position toward the workpiece W along the central axis Cw of the workpiece W, and advances the grindstone 20 toward the workpiece W with respect to the workpiece W. The state has an intersection angle θ.

Then, the control device 15 arranges the grindstone 20 and the workpiece W at the initial machining position. Specifically, as shown in FIGS. 5A and 5B, the control device 15 arranges the grindstone 20 in the circumferential direction of the workpiece W so as to have an offset angle φ while holding the intersection angle θ. The grindstone 20 is arranged at the initial processing position.

As a result, as shown in FIGS. 5A and 5B, the control device 15 is arranged so that the grindstone 20 has an intersection angle θ and an offset angle φ at the initial machining position. Further, in the control device 15, at the initial machining position, the arbor 21 passes through the inside of the workpiece W, and the rear end portion 23b of the grindstone tooth portion 23 (tooth side portion 23e) faces the workpiece W. Deploy.

Subsequently, in step S12, the control device 15 rotates the grindstone 20 and the workpiece W substantially synchronously clockwise in FIG. 5B (grinding process). Specifically, the control device 15 connects the drive motor for rotating the tool spindle 11 and the drive motor for rotating the workpiece spindle 12 to the point where the grindstone teeth 23a and the tooth surface We come into contact with each other. The rotation of the grindstone 20 and the workpiece W is controlled clockwise in FIG. 5B so that the rotational peripheral speed of the grindstone 20 is slightly faster than the rotational peripheral speed of the workpiece W in the rotation direction. Due to the intersection angle θ, the teeth of the workpiece W rotate from the tooth 23a of the grindstone 20 while the tooth side portion 23e moves in the tooth width (tooth streak) direction of the workpiece W along the tooth surface We of the workpiece W. It will be delayed in the direction.

Then, in step S13, when the grindstone 20 is moved backward relative to the work W in the direction of the central axis Cw of the work W, the control device 15 moves backward along the tooth surface We of the work W on the tooth side. While the portion 23e moves in the tooth width (tooth streak) direction of the workpiece W, the teeth of the workpiece W precede the grindstone teeth 23a of the grindstone 20 in the rotational direction. The teeth (tooth surface We) of the workpiece W and the grindstone teeth 23a of the grindstone 20 are in mesh with each other due to the advance and the delay in the rotation direction, and the tooth surface We of the workpiece W is ground ( Grinding process). Specifically, the control device 15 drives and controls the ball screw mechanism for moving the tool spindle 11 and the drive motor to move the grindstone 20 to the workpiece W as shown in FIGS. 6A and 6B. It is moved backward relative to the direction of the central axis Cw of W and passes through the inside of the workpiece W from the initial machining position. As a result, the grindstone teeth 23a, that is, the tooth side portions 23e of the grindstone tooth portion 23 of the grindstone 20 come into contact with the tooth surface We of the workpiece W, and as a result, the tooth surface We is ground.

In this case, the control device 15 drives and controls the ball screw mechanism and the drive motor for moving the work spindle 12 instead of driving and controlling the ball screw mechanism and the drive motor for moving the tool spindle 11. You can also do it. In this case, since the work piece W moves relative to the work piece 20 and the grindstone 20 moves backward relative to the work piece W, the grindstone 20 is moved from the initial machining position to the inside of the work piece W. Can be passed through. Therefore, also in this case, the tooth 23a of the tooth portion 23 of the grindstone 20, that is, the tooth side portion 23e comes into contact with the tooth surface We of the workpiece W, and the tooth width (tooth streak) of the workpiece W is along the tooth surface We. ), The tooth surface We is ground by moving the tooth side portion 23e.

It is also possible to perform so-called through coolant, in which coolant is supplied from the grindstone 20 when the grindstone 20 performs the grinding process. As a result, by performing the through coolant, the coolant can be efficiently supplied to the workpiece W (tooth surface We) of the workpiece W and the grindstone teeth 23a (tooth side portion 23e) of the grindstone 20 with a simple structure. .. Therefore, it is possible to improve the grinding quality and the grinding accuracy in the grinding process.

When the grindstone 20 is moved backward in step S13 to grind the tooth surface We of the workpiece W, the control device 15 ends the execution of the machining program in step S14. Then, after the next workpiece W is fixed to the workpiece spindle 12, the control device 15 executes the machining program again in step S10.

(5. Effect of grinding method with grindstone)
As described above, when the workpiece W is ground according to the grinding method using the grindstone of the present invention, the grindstone 20 grinds from the initial position. When the grindstone 20 is arranged at the initial processing position, the grindstone 20 has an intersection angle θ and an offset angle φ. Here, as shown in FIG. 10, the offset angle φ is determined so that the length of the first perpendicular line D1 is shorter than the length of the second perpendicular line D2. Therefore, as shown in FIG. 10, the grindstone 20 contacts the tooth surface We, which is the workpiece Ww of the workpiece W, on the front end portion 23c side of the tooth side portion 23e of the grindstone tooth 23a, which is the grinding portion. To do. The notch in the rotation direction of the workpiece W with respect to the tooth surface We of the tooth side portion 23e is deep on the front end portion 23c side and gradually becomes shallower toward the rear end portion 23b. Since the cut is made from the rear end 23b side of the front end 23c, wear of the front end 23c is suppressed.

Here, as a comparative example, as shown in FIG. 11, for example, the grindstone 20 is advanced toward the work piece W to move the tooth surface We of the work piece W, as in the skiving process widely performed conventionally. Assume the case of grinding. In this case, the cut is made in the deepest state in the rotation direction of the workpiece W from the front end 23c of the grindstone teeth 23a constituting the grindstone tooth portion 23 of the grindstone 20 to the tooth surface We of the tooth side portion 23e. Then, the notch in the rotation direction of the workpiece W with respect to the tooth surface We of the tooth side portion 23e sharply becomes shallow toward the rear end portion 23b.

Therefore, the amount of grinding (work amount) when the front end portion 23c grinds the workpiece W becomes remarkably large. Therefore, when the grindstone 20 is advanced to perform the grinding process, the wear of the front end portion 23c of the grindstone tooth portion 23 (grindstone tooth 23a) becomes remarkably large, and abnormal wear occurs.

On the other hand, in the processing method of the present invention, the uneven wear of the grindstone 20 can be reduced. Therefore, the durability of the grindstone 20 can be improved, and as a result, the life of the grindstone 20 can be extended, that is, the life of the grindstone 20 can be extended.

10 ... Gear grindstone (machine tool), 11 ... Tool spindle (spindle), 11a ... Chuck, 12 ... Work spindle, 12a ... Holder, 12b ... Turntable, 13 ... Column, 14 ... X-axis table, 15 ... Control device, 20 ... Grindstone (tool), 21 ... Arbor, 22 ... Grindstone body, 23 ... Grindstone tooth (machined), 23a ... Grindstone tooth, 23b ... Rear end, 23c ... Front end, 23d ... Tooth tip Part, 23e ... Tooth side (grinding part), 23f ... Tooth bottom, W ... Machine tool, Ww ... Work part, We ... Tooth surface, Pc ... Machining point, Ct ... (Tool) center axis, Cw ... ( (Workpiece) central axis, θ ... intersection angle, φ ... offset angle, D1 ... first vertical line, D2 ... second vertical line, M ... tool side spindle device, N ... workpiece side spindle device

Claims (7)

It is rotationally driven via a shaft member coaxially connected to the spindle of the machine tool, and can move forward and backward relative to the central axis of the work with respect to the annular work. Grinding with a grindstone that grinds the groove-shaped workpiece created in the rotationally driven geographic feature using a grindstone with one or more ridges that have components in the direction of the central axis. It's a method
The machined portion is a cylinder having an outer peripheral surface as a grinding portion and having the same diameter in a range from the rear end portion on the shaft member side to the front end portion on the opposite side to the rear end portion in the direction of the central axis. It is formed so as to have a circumscribed surface,
In order to bring the ground portion of the processed portion into contact with the workpiece, the grindstone is tilted so that the central axis of the grindstone and the central axis of the workpiece have a predetermined crossing angle, and the grindstone is tilted. Is moved along the circumferential direction of the workpiece to be offset so as to have an offset angle, and further, the workpiece is located at the initial machining position where the workpiece is on the spindle side of the grinding portion of the machining portion. The placement process for arranging the workpiece and the grindstone,
In a state where the workpiece and the grindstone are rotated in synchronization, the grindstone arranged at the initial machining position is moved backward relative to the workpiece to make the workpiece into the workpiece. A grinding method using a grindstone, comprising a grinding process in which the workpiece is brought into contact with the ground to be ground. The crossing angle includes a clearance angle between the machined portion and the machined portion.
The method for grinding with a grindstone according to claim 1, wherein in the grinding step, the portion to be processed is ground at the front end portion. The method for grinding with a grindstone according to claim 1 or 2, wherein the groove shape of the workpiece is extended in the tooth width direction of the workpiece. The method for grinding with a grindstone according to any one of claims 1-3, wherein the groove shape of the workpiece is a tooth profile. The method for grinding with a grindstone according to any one of claims 1-4, wherein the workpiece is created on at least one of the inner peripheral surface and the outer peripheral surface of the workpiece. The offset angle is
When the workpiece is created on the inner peripheral surface of the workpiece, a first perpendicular line extending from the rear end portion of the grinding portion in contact with the workpiece to the central axis of the workpiece. Is determined to be smaller than the length of the second perpendicular extending from the front end of the grinding site in contact with the workpiece to the central axis of the workpiece.
The fifth aspect of the present invention, wherein when the workpiece is created on the outer peripheral surface of the workpiece, the length of the first perpendicular line is determined to be larger than the length of the second perpendicular line. Grinding method using a grindstone. The grinding method according to claim 6, wherein the workpiece is an internal gear having internal teeth created on the inner peripheral surface or an external gear having external teeth created on the outer peripheral surface.

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