JP2023153670A - cam grinder - Google Patents

Abstract

To provide a cam grinder capable of coping with individual variation of a workpiece, and enhancing processing accuracy.SOLUTION: A cam grinder 1 for grinding processed parts 41-44 of a workpiece 4 on the basis of profile data 302b into a non-circular cam shape, comprises: a main shaft table 14 which has a workpiece drive motor 141 for rotating the workpiece 4 around a rotary axis line O1; a grind stone table 16 which has a grind stone drive motor 161 for rotating a grind stone 10 for grinding the processed parts 41-44; a grind stone feeding unit 17 which has a grind stone feeding motor 171 for advancing and retreating the grind stone 16; a measuring unit 2 for measuring dimensions of the processed parts 41-44; and an NC control unit 3. The measuring unit 2 measures dimensions of the processed parts 41-44 during grinding thereof, the NC control unit 3 controls the grind stone table feeding motor 171 so that shapes of the processed parts 41-44 match the profile data 302b, on the basis of the measurement result of the measuring unit 2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a cam grinding machine that grinds a processed portion of a shaft-shaped workpiece into a non-circular cam shape based on profile data.

Conventionally, cam grinding machines that grind camshafts used in vehicle engines, for example, use a camshaft material formed by casting as the workpiece, and rotate the workpiece around its axis using a headstock motor. , the workpiece is ground into a non-circular cam shape using a grindstone. The grindstone is rotationally driven by a grindstone drive motor attached to a grindstone head. The grindstone head is moved forward and backward in a direction perpendicular to the rotational axis of the workpiece by a grindstone feed motor fixed to the bed. The outer diameter of the cam part, which is the part to be machined, directly affects the amount of lift of the piston in the engine, so high machining accuracy is required. As a method for increasing the accuracy of grinding of a camshaft, a method described in, for example, Patent Document 1 has been proposed.

In the grinding machine described in Patent Document 1, the headstock motor and the grindstone feed motor are controlled based on a processing program to perform grinding processing using a grindstone, and then the workpiece is detected while it is supported at the processing position. The shape of the part to be machined is measured using a machine, and the machining program is corrected based on the error data obtained from the measurement.

Japanese Patent Application Publication No. 6-91489

When grinding a camshaft, the distance from the center of rotation to the outer peripheral surface of the cam part changes depending on the rotation angle of the camshaft, so it is necessary to move the grindstone back and forth in the cutting direction in synchronization with the rotation of the camshaft. , machining errors are likely to occur due to a delay in tracking the position of the grindstone. In addition, in the method described in Patent Document 1, the shape of the workpiece is measured on the machine after grinding, so the next workpiece cannot be machined while the measurement is being carried out, which takes time. The number of units produced per unit will decrease.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a cam grinding machine that can suppress a decrease in the number of machines produced per hour while improving machining accuracy.

In order to achieve the above object, the present invention provides a cam grinding machine that grinds a processed portion of a shaft-shaped workpiece into a non-circular cam shape based on profile data consisting of a phase and a lift amount, a headstock having a workpiece drive motor that rotates an object around a rotation axis; a grindstone head having a grindstone drive motor that rotationally drives a grindstone for grinding the workpiece; a grinding wheel head feeding device having a grinding wheel head feeding motor that moves forward and backward in a direction perpendicular to the axis; a measuring device that measures the dimensions of the workpiece; and controlling the workpiece drive motor based on the phase; a control device that controls the grindstone drive motor and controls the grindstone feed motor based on the lift amount, and the measurement device measures dimensions of the workpiece during grinding of the workpiece. The control device creates corrected profile data consisting of a phase and a lift amount by correcting the profile data based on the measurement results of the measuring device, so that the shape of the processed part matches the profile data. The present invention provides a cam grinding machine that controls the grindstone feed motor based on the corrected lift amount.

According to the cam grinding machine according to the present invention, it is possible to suppress a decrease in the number of machines produced per hour while improving machining accuracy.

1 is a schematic diagram showing a configuration example of a cam grinder according to an embodiment of the present invention. (a) is an explanatory diagram showing the shape of a processed portion of a workpiece. (b) is an explanatory view showing the shape of the processed portion of the workpiece during the grinding process together with a part of the grindstone. FIG. 2 is a configuration diagram showing an example of the configuration of a measuring device. FIG. 3 is an enlarged cross-sectional view showing a first measuring section of the measuring device. It is a block diagram which shows the measuring device based on a modification.

[Embodiment]
Embodiments of the present invention will be described with reference to the drawings. The embodiments described below are shown as preferred specific examples for carrying out the present invention, and some portions specifically illustrate various technical matters that are technically preferable. However, the technical scope of the present invention is not limited to this specific embodiment.

FIG. 1 is a schematic diagram showing a configuration example of a cam grinder according to an embodiment of the present invention. This cam grinding machine 1 uses a shaft-shaped camshaft material formed by casting as a workpiece 4 to be machined, and while rotating the workpiece 4 around its axis, a plurality of The processed parts 41 to 44 are ground into a non-circular cam shape. The ground workpiece 4 is used as a camshaft for a vehicle engine. Hereinafter, the horizontal direction parallel to the rotational axis _O1 of the workpiece 4, which corresponds to the left-right direction in FIG. 1, will be referred to as the Z-axis direction, and the horizontal direction perpendicular to the rotational axis O1, which corresponds to the vertical direction in FIG. ₁ , will be referred to as the X-axis direction.

The cam grinding machine 1 includes a bed 11 that is a base, a table 12 that can move forward and backward in the Z-axis direction with respect to the bed 11, a table drive device 13 that moves the table 12 forward and backward, and a third machine that is attached to the table 12. The first headstock 14 and the second headstock 15, a whetstone head 16 having a whetstone drive motor 161 that rotationally drives the whetstone 10, a whetstone head feeder 17 that moves the whetstone head 16 forward and backward in the X-axis direction, and a workpiece 4. The machine includes a measuring device 2 for measuring the dimensions of the processed parts 41 to 44, and an NC control device 3. The measuring device 2 moves forward in the X-axis direction by a hydraulic cylinder 18 toward a position where the dimensions of the workpieces 41 to 44 can be measured when machining the workpiece 4, and after machining is completed, the measuring device 2 Retract to a position that does not interfere with attachment and detachment.

The workpiece 4 is supported between the first headstock 14 and the second headstock 15, and is rotated around the rotation axis _O1 by the workpiece drive motors 141, 151 of the first headstock 14 and the second headstock 15. Rotationally driven. The workpiece drive motors 141, 151 are provided with angular position detectors 141a, 151a such as encoders that detect the angular position of the rotor relative to the stator. A center hole is formed in both ends of the workpiece 4 in the axial direction, and a center 140 of the first headstock 14 and a center 150 of the second headstock 15 are fitted into the center hole. Workpiece drive motors 141 and 151 rotate workpiece 4 via centers 140 and 150. Hereinafter, the rotation speed of the centers 140, 150 will be referred to as the spindle rotation speed, and one rotation of the centers 140, 150 together with the workpiece 4 will be referred to as one rotation of the spindle.

The table drive device 13 includes a table drive motor 131 and a ball screw shaft 132 that is rotationally driven by the table drive motor 131. The ball screw shaft 132 is screwed into a ball screw nut (not shown) fixed to the table 12, and as the ball screw shaft 132 rotates, the table 12 is guided by the guide rail 111 fixed to the bed 11, and the table 12 is guided by the guide rail 111 fixed to the bed 11. Moves forward and backward in the axial direction.

The grindstone drive motor 161 rotates _{the disc-shaped grindstone 10 about a rotation axis O 2 parallel} to the rotation axis O 1 of the workpiece 4 . The grindstone feed device 17 includes a grindstone feed motor 171 and a ball screw shaft 172 that is rotationally driven by the grindstone feed motor 171, and the ball screw shaft 172 has a ball (not shown) fixed to the grindstone head 16. It is screwed into a screw nut. As the ball screw shaft 172 rotates, the grindstone head 16 is guided by guide rails 112 and 113 fixed to the bed 11 and moves forward and backward in the X-axis direction.

The NC control device 3 controls the table drive motor 131, workpiece drive motors 141, 151, grindstone drive motor 161, and grindstone feed motor 171. When processing the workpiece 4, the workpiece drive motors 141, 151 and the grindstone feed motor 171 are synchronized while the grindstone 10 is rotated by the grindstone drive motor 161, and the workpieces 41 to 44 are ground by the grindstone 10. . The parts to be machined 41 to 44 are arranged at intervals in the axial direction of the workpiece 4. The NC control device 3 controls the table drive motor 131 to move the workpiece 4 in the Z-axis direction, and sequentially positions the workpieces 41 to 44 at processing positions facing the grindstone 10. The table drive motor 131, workpiece drive motors 141 and 151, and grindstone feed motor 171 are servo motors capable of highly accurate positioning, and are supplied with motor current from drive circuits 191 to 194.

The NC control device 3 has a storage section 30. The storage unit 30 includes a machining program 301 for controlling the table drive motor 131, the workpiece drive motor 141, the grindstone drive motor 161, and the grindstone feed motor 171, and workpiece information 302 that is information about the workpiece 4. Whetstone information 303, which is information about the whetstone 10, is stored. The workpiece information 302 includes material base circle diameter information 302a indicating the material base circle diameter which is the material diameter of the circular portion of the workpiece 4, profile data 302b of the cam portion outside the circular portion of the workpiece 4, and this information. This includes corrected profile data 302c obtained by correcting profile data 302b. The profile data 302b and the correction profile data 302c include the phase and lift amount of the cam portion (see FIG. 2, which will be described later). The profile data 302c is the original data of the cam portion, and the corrected profile data 302c is data that takes into account the follow-up delay of the grindstone 16 in order to process the processed parts 41 to 44 according to the profile data 302b. . The profile data 302b is entered as is into the original corrected profile data 302c. The machining program 301 describes the cutting depth, cutting speed, spindle rotation speed, etc. during grinding. The grindstone information 303 includes information on the diameter of the grindstone, which indicates the diameter of the grindstone 10 before processing the workpiece 4.

The NC control device 3 includes a base circle diameter calculation device 31 and a grindstone position data calculation device 32. The base circle diameter calculation device 31 calculates the base circle diameter of the workpieces 41 to 44 during machining based on the workpiece base circle diameter shown in the workpiece base circle diameter information 302a and the cutting amount and cutting speed of the grindstone 10. Calculate the hour-based circle diameter. The grindstone position data calculation device 32 determines the target in the X-axis direction of the grindstone head 16 based on the correction profile data 302c, the base circle diameter during machining calculated by the base circle diameter calculation device 31, and the grindstone diameter shown in the grindstone information 303. Grindstone position data, which is the position, is calculated, and this grindstone position data and workpiece rotation angle data, which is the target value of the rotation angle (phase) of the workpiece 4, are stored.

The NC control device 3 transmits the grindstone position data calculated by the grindstone position data calculation device 32 to the drive circuit 19 that drives the grindstone feed motor 171. The drive circuit 19 is a servo amplifier, and supplies a motor current to the grindstone feed motor 171 so as to position the grindstone 16 at the position indicated by the grindstone position data. Further, the NC control device 3 uses the workpiece rotation angle data calculated by the grindstone position data calculation device 32 to drive circuits 192 and 193 that drive the workpiece drive motors 141 and 151 of the first headstock 14 and the second headstock 15. Send to. The drive circuits 192 and 193 are servo amplifiers, and supply motor current to the workpiece drive motors 141 and 151 so as to position the workpiece 4 at a position corresponding to the workpiece rotation angle data. The base circle diameter during machining gradually decreases each time the spindle rotates by the amount of cut per spindle rotation, which is obtained by dividing the cutting speed of the grindstone head 16 by the spindle rotation speed. The base circle diameter during machining changes every time the main shaft rotates once, and the correction profile data 302c also changes, so the grindstone position data also changes in the same way.

FIG. 2(a) is an explanatory diagram showing the shape of the processed portion 41 of the workpiece 4. As shown in FIG. In FIG. 2(a), the outer peripheral surface 41a after grinding, which is a finished surface, is shown by a solid line, and the pre-processing outline 41b, which shows the external shape of the processed portion 41 before grinding, is shown by a two-dot chain line. A portion between the unprocessed outline line 41b and the outer circumferential surface 41a is a grinding allowance 410 to be removed by grinding. Note that the other processed parts 42 to 44 also have similar shapes.

As shown in FIG. 2(a), the processed part 41 includes a circular part 411 having a circular shape when viewed along the rotation axis _O1 , which is the center of rotation during processing, and a cam having a non-circular cam shape. portion 412. The circular portion 411 has a constant distance from the rotation axis O ₁ to the outer circumferential surface 41 a, and the cam portion 412 has a longer distance from the rotation axis O ₁ to the outer circumferential surface 41 a than the circular portion 411 . The distance D from the rotation axis _O1 to the outer peripheral surface 41a in the circular portion 411 is the base circle diameter. The profile data 302b and the correction profile data 302c include the lift amount L, which is the difference between the distance from the rotation axis _O1 to the outer peripheral surface 41a and the base circle diameter D, for each predetermined angle (for example, 5 degrees) of the workpiece 4. It is set. In FIG. 2(a), typical angles of the workpiece 4 are shown as 0°, 90°, 180°, and 270°. The maximum value of the lift amount L varies depending on the displacement of the engine in which the camshaft is used, but is, for example, 3 to 5 mm.

FIG. 2(b) is an explanatory diagram showing the shape of the processed portion 41 of the workpiece 4 during the grinding process together with a part of the grindstone 10. As shown in FIG. The workpiece 41 is ground by the grindstone 10 while being rotated multiple times by the first headstock 14 and the second headstock 15 . In addition, in FIG. 2(b), the amount of grinding per rotation of the main shaft is exaggerated.

During one rotation of the workpiece 4, the part to be machined 41 is cut by the amount of cut per one revolution of the spindle, so the outer diameter of the part to be machined 41 during machining is spiral as shown in FIG. 2(b). It becomes like this. As shown in FIG. 2(b), when the grinding wheel 10 is in contact with the 0° phase, a step equal to the amount of cut per spindle rotation is created at the 0° phase, and 4 steps are created at the 90° phase. There will be 3/4 left uncut, and a 270° phase will leave 1/4 uncut. After cutting the amount of cutting described in the machining program 301, if the actual external shape of the processed part 41 after grinding does not match the outer circumferential surface 41a indicated by the profile data 302b, The difference becomes a machining error.

In this embodiment, in order to reduce this machining error and improve machining accuracy, the measuring device 2 measures the outer diameter dimension of the to-be-processed parts 41 to 44 while they are being ground by the grindstone 10. That is, during the grinding process of the workpiece part 41, the measuring device 2 measures the outer diameter dimension of the workpiece part 41 over the entire circumference, and the grinding process of the workpiece part 42 that is performed subsequently after the workpiece part 41 is processed. Inside, the measuring device 2 measures the outer diameter dimension of the processed portion 42 over the entire circumference. The same applies to the other processed parts 43 and 44.

Here, in a general sizing device using a differential transformer, the difference between the maximum and minimum measurable dimensions is, for example, about 1.2 mm, so the maximum value of the lift amount L is It is not possible to measure a cam shape of about 3 to 5 mm over the entire circumference. For this reason, in this embodiment, as the measuring device 2 for measuring the outer diameters of the workpieces 41 to 44, a device capable of measuring a wider dimensional range than a conventional general sizing device is used.

FIG. 3 is a configuration diagram showing an example of the configuration of the measuring device 2. As shown in FIG. The measurement device 2 includes a measurement control device 20, a frame 21 formed by connecting an upper wall 211 and a lower wall 212 by a side wall 213, and guide rails 221 and 222 suspended between the upper wall 211 and the lower wall 212. , first and second slide blocks 231 and 232 that slide while being guided by guide rails 221 and 222, the first measurement unit 24 and digital scale 251 fixed to the first slide block 231, and the second The second measuring section 26 and scale reader 252 fixed to the slide block 232, the first moving mechanism 27 that moves the first measuring section 24, and the second moving mechanism that moves the second measuring section 26. 28 and drive circuits 291 and 292.

The first moving mechanism 27 includes a first screw shaft 271 that is screwed into the first slide block 231, and a first motor 272 that rotates the first screw shaft 271. The second moving mechanism 28 includes a second screw shaft 281 that is screwed into the second slide block 232, and a second motor 282 that rotates the second screw shaft 281. The first motor 272 and the second motor 282 are servo motors, and detection signals from the angular position detectors 272a and 282a are output to the drive circuits 291 and 292. The drive circuits 291 and 292 are servo amplifiers that supply motor current to the first and second motors 272 and 282 based on commands from the measurement control device 20. The drive circuits 291 and 292 perform feedback control so that the detection signals of the angular position detectors 272a and 282a become the same as the commands from the measurement control device 20.

The measuring device 2 is arranged so that the guide rails 221 and 222 extend in a vertical direction perpendicular to the X-axis direction and the Z-axis direction. In FIG. 3, the first slide block 231 and the first measuring section 24 are shown in cross section. The first slide block 231 is formed with insertion holes 231a and 231b through which the pair of guide rails 221 and 222 are inserted, respectively. The second slide block 232 is configured similarly to the first slide block 231, and the second measuring section 26 is configured similarly to the first measuring section 24.

A male threaded portion 271a of a first screw shaft 271 is screwed into the first slide block 231, and when the first screw shaft 271 rotates in the _R1 direction shown in FIG. moves toward the lower wall 212, the first probe 244 approaches the rotation axis _O1 of the workpiece 4, and the first screw shaft 271 rotates in the _R2 direction, the first slide block 231 moves upward. The first probe 244 moves toward the wall 211 and separates from the rotation axis O ₁ of the workpiece 4 . Similarly, a male threaded portion 272a of a second screw shaft 272 is screwed into the second slide block 232, and when the second screw shaft 272 rotates in the _R1 direction, the second slide block 232 rotates. When the second probe 264 moves toward the lower wall 212 and separates from the rotation axis _O1 of the workpiece 4, and the second screw shaft 272 rotates in the _R2 direction, the second slide block 232 moves toward the upper wall. 211 side, the second probe 264 approaches the rotation axis O ₁ of the workpiece 4 .

FIG. 4 is an enlarged cross-sectional view showing the first measuring section 24. As shown in FIG. The first measurement unit 24 includes a case member 241, a pivot pin 242 fixed to the case member 241, a first swing arm 243 that is supported by the pivot pin 242 and is swingable, and a first The first measuring element 244 attached to the tip of the swinging arm 243 is biased so that the first measuring element 244 comes into contact with the workpiece parts 41 to 44 of the workpiece 4. The iron core 246 is connected to the rear end of the first swing arm 243, and the coil 247 is provided to surround the iron core 246. The case member 241 is formed with a spring housing hole 241 a for housing the first spring 245 and a coil housing hole 241 b for housing the coil 247 . A fixing pin 248 is fixed to the bottom of the spring housing hole 241a, and a first spring 245 is arranged around the fixing pin 248.

The iron core 246 and the coil 247 constitute a first displacement detector 240 that detects the amount of displacement of the first probe 244 . The coil 247 generates a magnetic field therein by the current supplied from the measurement control device 20. The iron core 246 is connected to the rear end of the first swing arm 243 by a connecting member 249 and is supported inside the coil 247 . When the first swing arm 243 swings, the iron core 246 moves in the axial direction of the coil 247 inside the coil 247, the impedance of the coil 247 changes depending on the position of the iron core 246, and the current flows through the coil 247. changes. The measurement control device 20 uses this change in current as a detection signal for the first displacement detector 240.

The second measurement unit 26 includes a second swing arm 263 that swings while being supported by a pivot pin 262 fixed to a case member 261, and a second swing arm 263 that swings while being supported by a pivot pin 262 fixed to a case member 261. a second spring 265 that biases the second swinging arm 263 so that the second measuring element 264 comes into contact with the workpiece parts 41 to 44 of the workpiece 4, an iron core 266, and a coil. 267 and a second displacement detector 260 that detects the amount of displacement of the second measuring element 264. When the second swing arm 263 swings, the detection signal of the second displacement detector 260 changes.

The first measuring element 244 and the second measuring element 264 form a pair at positions sandwiching the rotational axis O ₁ of the workpiece 4 so as to contact the workpieces 41 to 44, respectively. For example, during machining of the workpiece 41, the rotation of the workpiece 4 causes the cam portion 412 of the workpiece 41 to expand the distance between the first gauge stylus 244 and the second gauge stylus 264, causing the first oscillation. The movable arm 243 and the second swing arm 263 are caused to swing. As a result, the detection signals of the first displacement detector 240 and the second displacement detector 260 change.

The range in which the displacement amount of the first measuring element 244 and the second measuring element 264 can be detected by the first displacement detector 240 and the second displacement detector 260 is limited to a narrow range of about 1.2 mm, for example. . Therefore, in the present embodiment, the measurement control device 20 controls the first and second motors 272 and 282 to control the first measurement section 24 and the second measurement section according to the rotational position of the workpiece 4. Move 26.

Specifically, for example, when the first probe 244 contacts the circular portion 411 during processing of the workpiece 41, the first screw shaft 271 is rotated in the _R1 direction by the first motor 272. When the first probe 244 contacts the cam portion 412, the first motor 272 rotates the first threaded shaft 271 in the _R2 direction. Furthermore, when the second gauge stylus 264 contacts the circular portion 411, the second screw shaft 272 is rotated in the _R2 direction by the second motor 282, and the second gauge stylus 264 comes into contact with the cam portion 412. When doing so, the second screw shaft 272 is rotated in the _R1 direction by the second motor 282.

The measurement control device 20 includes a first position calculation device 201 that calculates the target position of the first measuring stylus 244 and a second position calculating device 202 that calculates the target position of the second measuring stylus 264. The first position calculation device 201 and the second position calculation device 202 receive signals of the workpiece rotation angle, profile data 302b, and base circle diameter during machining from the NC control device 3. When grinding the parts to be machined 41 to 44, the measurement control device 20 makes sure that the lower end of the first gauge stylus 244 is in contact with the parts to be machined 41 to 44, and the upper end of the second gauge 264 is in contact with the parts to be machined 41 to 44. The first measuring element 244 and the second measuring element 264 are moved to positions where they touch each other.

As shown in FIGS. 2 and 3, when the rotation angle of the workpiece 4 is 0°, the measurement control device 20 determines whether the lower end of the first probe 244 has a lift amount at a phase of 270° and a base during machining. A command is given to the drive circuit 291 of the first motor 272 to position it at a position that is the sum of the circle diameter and one-fourth of the cutting amount per rotation of the main shaft. In addition, the measurement control device 20 determines that the upper end of the second gauge head 264 is the sum of the lift amount at the 90° phase, the base circle diameter during machining, and three-quarters of the cutting amount per spindle rotation. A command is given to the drive circuit 292 of the second motor 282 in order to position the second motor 282 to the desired position.

When the rotation angle of the workpiece 4 is 90°, the measurement control device 20 determines whether the lower end of the first gauge stylus 244 has the lift amount at the 0° phase, the base circle diameter during machining, and the depth of cut per spindle rotation. A command is given to the drive circuit 291 of the first motor 272 to position the motor to a position that is the sum of one-fourth of the amount. In addition, the measurement control device 20 determines that the upper end of the second gauge stylus 264 is the sum of the lift amount at the 180° phase, the base circle diameter during machining, and three-quarters of the cutting amount per spindle rotation. A command is given to the drive circuit 292 of the second motor 282 in order to position the second motor 282 to the desired position.

When the rotation angle of the workpiece 4 is 180°, the measurement control device 20 determines that the lower end of the first gauge stylus 244 has a lift amount at a phase of 90°, a base circle diameter during machining, and a depth of cut per spindle rotation. A command is given to the drive circuit 291 of the first motor 272 to position the motor to a position that is the sum of one-fourth of the amount. In addition, the measurement control device 20 determines that the upper end of the second gauge head 264 is the sum of the lift amount at the 270° phase, the base circle diameter during machining, and three-quarters of the cutting amount per spindle rotation. A command is given to the drive circuit 292 of the second motor 282 in order to position the second motor 282 to the desired position.

When the rotation angle of the workpiece 4 is 270°, the measurement control device 20 determines whether the lower end of the first gauge stylus 244 has a lift amount at a phase of 180°, the base circle diameter during machining, and the depth of cut per spindle rotation. A command is given to the drive circuit 291 of the first motor 272 to position the motor to a position that is the sum of one-fourth of the amount. In addition, the measurement control device 20 determines that the upper end of the second gauge stylus 264 is the sum of the lift amount at the 0° phase, the base circle diameter during machining, and three quarters of the cutting amount per spindle rotation. A command is given to the drive circuit 292 of the second motor 282 in order to position the second motor 282 to the desired position. Note that for the lift amount in any of the above cases, the lift amount of the profile data 302b is used instead of the lift amount of the corrected profile data 302c.

The distance between the first slide block 231 and the second slide block 232 is determined by a linear scale consisting of a digital scale 251 fixed to the first slide block 231 and a scale reader 252 fixed to the second slide block 232. 25. In the linear scale 25, a scale reader 252 reads indicators such as graduations provided on a digital scale 251, and uses the reading result of the scale reader 252 as information indicating the interval between the first measuring section 24 and the second measuring section 26. Output to the measurement control device 20.

The measurement control device 20 has a workpiece part outer diameter value measuring device (actual measurement) 203, and this workpiece part outer diameter value measuring device (actual measurement) 203 is connected to the first to third adjusters 24a, 25a, 26a. It is connected. The first regulator 24a is connected to the first displacement detector 240 and adjusts the zero point and gain. The second regulator 25a is connected to the linear scale 25 and adjusts the zero point and gain. The third regulator 26a is connected to the second displacement detector 260 and adjusts the zero point and gain. The workpiece outer diameter value measuring device (actual measurement) 203 receives the signal from the first displacement detector 240 via the first regulator 24a, and receives the signal from the linear scale 25 via the second regulator 25a. and receives signals from the second displacement detector 260 via the third adjuster 26a, and calculates actual measured values of the outer diameters of the first to fourth workpieces 41 to 44 based on these signals. .

The measurement control device 20 also includes a workpiece outer diameter value measuring device (command) 204. The workpiece outer diameter value measuring device (command) 204 receives a signal of the position data of the first measuring point 244 from the first position calculating device 201, and also receives a signal of the position data of the first measuring point 244 from the second position calculating device 202. Upon receiving the H.264 position data signal, the outer diameter (command) of the part to be machined is calculated.

The measurement control device 20 also includes a correction calculation device 205. The correction calculation device 205 receives a signal of the outside diameter of the workpiece (actual measurement) from the workpiece outside diameter value measurement device (actual measurement) 203, and also receives the signal of the outside diameter of the workpiece from the workpiece outside diameter value measurement device (command) 204. Upon receiving the signal of the diameter (command), the value obtained by subtracting the outside diameter of the workpiece (actual measurement) from the outside diameter of the workpiece (command) is divided by 2, and the divided value is sent to the NC control device 3 as correction data. . When the rotation angle of the workpiece 4 is 0°, correction data for phases of 270° and 90° are sent to the NC control device 3. The rotation angle of the workpiece 4 and the phase of the cam portion 412 are the same, and the NC control device 3 adds this correction data to the lift amount in the correction profile data 302c as a new lift amount in the correction profile data 302c. Remember.

Grinding of the processed portion 41 of the workpiece 4 is performed using the grindstone position data calculated by the grindstone position data calculation device 32 and the phase of the cam portion 412. The grindstone position data is given as a command to the drive circuit 194 of the grindstone feed motor 171, and the workpiece rotation angle, which is the phase of the cam portion 412, is given to the workpiece drive motors of the first headstock 14 and the second headstock 15. The signal is given as a command to drive circuits 192 and 193 of 141 and 151. Here, the rotation angle of the workpiece 4 and the phase of the cam portion 412 are the same. In other words, when the rotation angle of the workpiece 4 is 0°, the phase of the cam portion 412 is 0°, and the grindstone position data corresponding to the 0° phase of the cam portion 412 is used. When is 90°, the phase of the cam portion 412 is 90°, and the grindstone position data corresponding to the phase of the cam portion 412 of 90° is used. Grinding of the processed parts 42 to 44 of the workpiece 4 is performed in the same manner.

The NC control device 3 determines that the measurement results of the measuring device 2 are not as expected in the grinding process and dimension measurement of the cam portion 412 during multiple rotations of the workpiece 4 by the first headstock 14 and the second headstock 15. If it is larger (if not enough), increase the amount of cut of the grindstone 10 when grinding the cam portion 412 during the next rotation, and if the measurement result of the measuring device 2 is smaller than expected (if too much has been removed) The amount of cut of the grindstone 10 during grinding of the cam portion 412 during the rotation of the grindstone 10 is reduced. That is, the NC control device 3 uses feedback to determine the position of the grindstone 16 during the next grinding of the cam portion 412, based on the measurement results of the dimensions of the cam portion 412 by the measuring device 2 after grinding the cam portion 412. Adjust.

(Modified example of measuring device)
FIG. 5 is a configuration diagram showing a measuring device 2A according to a modified example. In the configuration example shown in FIG. 3, the distance between the first slide block 231 and the second slide block 232 is determined by the digital scale 251 fixed to the first slide block 231 and the digital scale 251 fixed to the second slide block 232. Although the case where detection is performed using the linear scale 25 including the scale reader 252 has been described, in the modification shown in FIG. 5, the measuring device 2A does not have the linear scale 25. In this modification, the workpiece outer diameter value measuring device (actual measurement) 203 receives the distance between the first slide block 231 and the second slide block 232 from the first position calculation device 201 in a first measurement. The actual measurement of the outer diameter of the first to fourth workpieces 41 to 44 is calculated based on the position data of the probe 244 and the position data signal of the second probe 264 received from the second position calculation device 202. Calculate the value. The other configuration and processing contents of the measuring device 2A are the same as those described with reference to FIG. 3.

Also in this modification, the measurement results of the workpiece parts 41 to 44 of the workpiece 4 can be reflected in the correction profile data 302c, as in the case of using the measuring device 2 shown in FIG. The position of the grindstone head 16 during grinding can be adjusted in a feedback manner.

(Effects of embodiment)
According to the embodiment described above, the NC control device 3 corrects the correction profile data 302c based on the measurement results of the measuring device 2, and the grindstone position data calculation device 32 corrects the correction profile data 302c, the base circle diameter calculation device Based on the processing base circle diameter calculated by 31 and the grindstone diameter shown in the grindstone information 303, the grindstone position data, which is the target position of the grindstone 16 in the X-axis direction, is calculated, and this grindstone position data and machining are performed. The workpiece rotation angle data, which is the target value of the rotation angle (phase) of the object 4, is stored, and the grindstone position data calculation device 32 drives the grindstone feed motor 171 with the grindstone position data calculated by the grindstone position data calculation device 32. The workpiece drive motors 141 and 151 of the first headstock 14 and the second headstock 15 are driven using the workpiece rotation angle data calculated by 32. The correction profile data 302c is data that takes into account the follow-up delay of the grinding wheel head 16 in order to process the processed parts 41 to 44 according to the profile data 302b. By correcting 302c, the parts to be processed 41 to 44 can be processed according to the profile data 302b. In addition, since the measurement device 2 measures the dimensions of the parts 41 to 44 to be machined at the same time in parallel with the grinding process, compared to the case where the dimensions of the parts 41 to 44 to be machined are measured after the completion of grinding, it is possible to After the processing of the object 4 is completed, the next workpiece 4 can be processed immediately, and the number of units produced per hour can be prevented from decreasing.

(Additional note)
Although the present invention has been described above based on the embodiments, the embodiments do not limit the invention according to the claims. Furthermore, it should be noted that not all combinations of features described in the embodiments are essential for solving the problems of the invention. Moreover, the present invention can be implemented with appropriate modifications by omitting some configurations, or adding or replacing configurations, without departing from the spirit thereof. Further, it is also possible to combine some of the configurations of the plurality of embodiments described above, and it is also possible to modify, for example, as described below.

1... Cam grinding machine 10... Grinding wheel 14... Headstock 141... Workpiece drive motor 16... Grinding wheel head 161... Grinding wheel drive motor 17... Grinding wheel head feed device 171... Grinding wheel head feed motor 2... Measuring device 24... First measuring section 240... First displacement detector 244... First measuring element 25... Linear scale 26... Second measuring section 260... Second displacement detector 264... Second measuring element 27... First moving mechanism 28... Second moving mechanism 302b... Profile data 4... Workpieces 41 to 44... Processed part 411... Circular part 412... Cam part O ₁ ... Rotation axis

Claims (3)

A cam grinding machine that grinds a processed part of a shaft-shaped workpiece into a non-circular cam shape based on profile data consisting of a phase and a lift amount,
a headstock having a workpiece drive motor that rotates the workpiece about a rotation axis; a grindstone head having a grindstone drive motor that rotationally drives a grindstone for grinding the workpiece; a grinding wheel head feeding device having a grinding wheel head feeding motor that moves forward and backward in a direction perpendicular to the rotational axis; a measuring device that measures dimensions of the workpiece; and controlling the workpiece drive motor based on the phase. and a control device that controls the grindstone drive motor and controls the grindstone feed motor based on the lift amount,
The measuring device measures the dimensions of the processed part during grinding of the processed part,
The control device creates corrected profile data consisting of a phase and a lift amount by correcting the profile data based on the measurement results of the measuring device, and adjusts the profile data so that the shape of the processed portion matches the profile data. controlling the grindstone feed motor based on the corrected lift amount;
Cam grinder. The cam shape includes a circular part having a constant distance from the rotation axis to the outer peripheral surface, and a cam part having a longer distance from the rotation axis to the outer peripheral surface than the circular part, and having the phase and the lift amount set. and has
As the workpiece is rotated by the workpiece drive motor, the circular part and the cam part are ground by the grindstone and the dimensions are measured by the measuring device multiple times;
The control device corrects the lift amount of the cam portion next time according to the measurement result of the dimension of the cam portion by the measuring device after grinding the cam portion, and adjusts the lift amount at the time of grinding based on the corrected lift amount. adjusting the position of the grindstone head in
The cam grinder according to claim 1. The measuring device includes:
a first measuring section having a first measuring element that contacts the processed part;
a second measuring part having a second measuring element that contacts the workpiece at a position sandwiching the rotational axis of the workpiece between the second measuring element and the first measuring element;
a moving mechanism that makes the distance between the first measuring section and the second measuring section variable;
a measurement control device that controls the positions of the first measurement unit and the second measurement unit based on the profile data;
A cam grinder according to claim 1 or 2.

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