Grinding equipment

Abstract

To provide a grinding device that can be prevented from deteriorating in accuracy in machining a pin part even if there is a machining error in a diameter of a journal part.SOLUTION: A grinding device, which grinds a pin part of an eccentric shaft, is provided with: a radius measuring device that measures a radius of a journal part; a spindle, to which a V block fixed with the journal part is fixed, and which rotates around a spindle rotating shaft; a grindstone base provided to be movable in a direction in which the base crosses the spindle rotating shaft and to enable a grindstone for grinding the pin part to rotate; a deviation amount calculating part that calculates a deviation amount that is a distance between a shaft line of the journal part and the spindle rotating shaft, on the basis of the radius of the journal part measured by the radius measuring device; a grindstone position calculating part that calculates a position of the grindstone from the deviation amount, eccentric stroke and a phase of the spindle; a storing part that stores profile data showing a correspondence relation between the phase of the spindle and the position of the grindstone; and an operation control part that controls the phase of the spindle and a position of the grindstone with respect to the pin part, using the profile data.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a grinding device. [Background technology]

[0002] For example, Patent Document 1 discloses a cylindrical grinding machine in which a cylindrical journal is fixed to a V-block and a cylindrical pin that is eccentric with respect to the cylindrical journal is ground. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-9717 Summary of the Invention [Problem to be solved by the invention]

[0004] In the cylindrical grinding machine of Patent Document 1, if there is a machining error in the diameter of the journal part, the journal part cannot be properly positioned on the V-block, and the center of the journal part is shifted from the center of rotation of the main spindle, resulting in a problem of reduced machining accuracy of the pin part. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to a first aspect of the present disclosure, there is provided a grinding device for grinding a pin portion of an eccentric shaft, the pin portion having an axis eccentric from the axis of the journal portion by an eccentric stroke. the grinding machine includes a diameter measuring device that measures the diameter of the journal portion, a V-block having a V-groove and supporting the journal portion by the V-groove, a clamping mechanism that fixes the journal portion to the V-groove, a spindle to which the V-block is fixed and that rotates about a spindle rotation axis, a grinding wheel head that is provided movable in a direction intersecting the spindle rotation axis and on which a grinding wheel that grinds the pin portion is rotatably mounted, a deviation amount calculating unit that calculates a deviation amount, which is the distance between the axis of the journal portion and the spindle rotation axis, based on the diameter of the journal portion measured by the diameter measuring device, a grinding wheel position calculating unit that calculates a position of the grinding wheel from the deviation amount, the eccentric stroke, and the phase of the spindle, a memory unit that stores profile data that indicates a correspondence relationship between the phase of the spindle and the position of the grinding wheel, and an operation control unit that controls the phase of the spindle and the position of the grinding wheel relative to the pin portion using the profile data. According to this type of grinding device, the amount of deviation, which is the distance between the axis of the journal and the rotation axis of the main spindle, is calculated based on the diameter of the journal measured by the diameter measuring device, the position of the grinding wheel is calculated from the amount of deviation, the eccentric stroke, and the phase of the main spindle, profile data indicating the correspondence between the phase of the main spindle and the position of the grinding wheel is stored, and the phase of the main spindle and the position of the grinding wheel are controlled using the stored profile data, so that the pin portion can be machined with high precision even if there is a machining error in the diameter of the journal. (2) In the grinding device of the above aspect, the angle of the V-groove of the V-block may be 90°, and the diameter of a reference journal having an axis coinciding with the spindle rotation axis may be X, and the diameter of the journal portion measured by the diameter measuring device may be Y. The grinding device of this aspect allows the amount of deviation to be calculated easily. (3) In the grinding device of the above aspect, the grindstone position calculation unit may calculate the position of the grindstone according to the diameter of the grindstone and the diameter of the pin portion. According to this aspect, the grinding device can calculate the position of the grindstone when grinding the pin portion of an eccentric shaft having a cylindrical pin portion. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is an explanatory diagram showing a schematic configuration of a grinding device. [Figure 2] FIG. 2 is a cross-sectional view of the chuck taken along a cross section perpendicular to the Z axis. [Figure 3] FIG. 2 is a top view of the diameter measurement device. [Figure 4] FIG. 2 is a side view of the diameter measurement device. [Figure 5] FIG. 2 is a diagram illustrating the configuration of a control unit. [Figure 6] FIG. 10 is a process diagram of grinding the pin portion of the eccentric shaft using a grinding device. [Figure 7] 10A and 10B are diagrams illustrating a deviation amount calculated by a deviation amount calculation unit. [Figure 8] 10A and 10B are diagrams illustrating calculation of the distance between the spindle rotation axis and the grindstone rotation axis. [Figure 9] FIG. 10 is a diagram illustrating control of the phase of the spindle and the position of the grindstone. [Figure 10] FIG. 10 is a diagram illustrating control of the phase of the spindle and the position of the grindstone. [Figure 11] FIG. 10 is a diagram illustrating control of the phase of the spindle and the position of the grindstone. [Figure 12] FIG. 10 is a diagram illustrating control of the phase of the spindle and the position of the grindstone. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. First embodiment: FIG. 1 is an explanatory diagram showing the schematic configuration of a grinding apparatus 100. FIG. 1 shows arrows representing three mutually orthogonal coordinate axes, namely, X, Y, and Z axes. The Z and X axes are coordinate axes parallel to the horizontal plane. The Y axis is a coordinate axis parallel to the vertical direction. The arrows representing the X, Y, and Z axes in FIG. 1 and the arrows representing the X, Y, and Z axes in other figures point in the same direction. When specifying the direction, positive and negative signs are used in combination to indicate the direction, with "+" indicating the positive direction, which is the direction indicated by the arrow, and "-" indicating the negative direction, which is the opposite direction to the direction indicated by the arrow.

[0009] The grinding apparatus 100 grinds the pin portion B of an eccentric shaft W, which includes a journal portion A and a pin portion B having an axis eccentric by an eccentric stroke from the axis of the journal portion A. In this embodiment, the pin portion B has a cylindrical shape. The grinding apparatus 100 includes a bed 10, a table 20, a grinding wheel head 30, a table movement motor 40, a grinding wheel head movement motor 50, a diameter measuring device 60, a control unit 70, and drive circuits 81, 82, and 83.

[0010] The bed 10 supports the table 20 and the wheel head 30. The bed 10 is made of, for example, cast iron. On the upper surface of the bed 10, a sliding surface is formed for the table 20 to move along the Z-axis direction, and a sliding surface is formed for the wheel head 30 to move along the X-axis direction.

[0011] The table 20 is disposed on the upper surface of the bed 10. A headstock 21 and a tailstock 26 are attached to the upper surface of the table 20.

[0012] The headstock 21 includes a spindle 22 , a chuck 23 , a spindle rotation motor 24 , and a spindle encoder 25 .

[0013] 2 is a cross-sectional view of the chuck 23 taken along a plane perpendicular to the Z axis. The chuck 23 is fixed to the spindle 22. The chuck 23 has a bracket 231, a V-block 232, a positioning block 234, and a clamping mechanism 250.

[0014] The bracket 231 is substantially U-shaped and is attached to the tip surface of the main shaft 22. The bracket 231 has a recess 236.

[0015] Two V-blocks 232 are attached in series in the Z-axis direction to recesses 236 of the bracket 231. A V-groove 237 that supports the journal portion A of the eccentric shaft W is formed in the V-block 232.

[0016] The positioning block 234 is attached closer to the main shaft 22 than the V-block 232. The positioning block 234 abuts against the end of the eccentric shaft W on the main shaft 22 side, thereby determining the position of the eccentric shaft W in the Z-axis direction.

[0017] The clamp mechanism 250 includes a clamp arm 235, a pivot pin 238, a cylinder rod 239, a pin 241, and a piston 242. The clamp arm 235 is attached to the side of the V-block 232. The clamp arm 235 is supported by the pivot pin 238 so that it can rotate around the pivot pin 238. A cylinder rod 239 is attached to one end of the clamp arm 235 by a pin 241 via an elongated hole 240 provided in the clamp arm 235. The cylinder rod 239 is fixed to the piston 242. As the piston 242 moves in the X-axis direction, the clamp arm 235 rotates around the pivot pin 238. As the piston 242 moves in the positive direction of the X-axis in FIG. 2, the clamp arm 235 rotates counterclockwise around the pivot pin 238. At this time, the journal portion A of the eccentric shaft W is pressed against the V-groove 237 by the claw 243 provided on the other end of the clamp arm 235. In this manner, the journal portion A is fixed to the V-groove 237 by the clamp mechanism 250. If there is no processing error in the diameter of the journal portion A, the eccentric shaft W is fixed to the chuck 23 so that the axis Oa of the journal portion A is coincident with the spindle rotation axis AX, which is the axis of the spindle 22. Note that the clamp mechanism 250 need not necessarily have the clamp arm 235, as long as it is a mechanism that can fix the journal portion A to the V-groove 237.

[0018] The spindle motor 24 shown in FIG. 1 drives the spindle 22 to rotate about the spindle rotation axis AX. As the spindle 22 rotates, the chuck 23 and eccentric shaft W fixed to the spindle 22 rotate about the spindle rotation axis AX. The spindle encoder 25 is disposed on the spindle rotation motor 24. A signal from the spindle encoder 25 is fed back to the drive circuit 83. The spindle encoder 25 detects the phase of the spindle 22 (the angular position about the spindle rotation axis AX) and sends it to the drive circuit 83.

[0019] The tailstock 26 is disposed opposite the headstock 21 in the Z-axis direction with the workpiece W sandwiched therebetween. The tailstock 26 includes a center 27. The center 27 supports the other end of the workpiece W in the Z-axis direction so that the workpiece W can rotate around the spindle rotation axis AX.

[0020] The wheel head 30 is disposed on the upper surface of the bed 10. The wheel head 30 includes a wheel 31, a wheel spindle 32, and a wheel rotation motor 33.

[0021] The grinding wheel 31 grinds the surface of the pin portion B of the eccentric shaft W. The grinding wheel 31 is composed of a core 311 and a grinding wheel layer 312. The core 311 is disk-shaped and made of metal such as iron. The core 311 is detachably connected to the grinding wheel shaft 32 by bolts or the like (not shown). The grinding wheel layer 312 is disk-shaped and provided on the outer periphery of the core 311. The grinding wheel layer 312 is formed by mixing abrasive grains and a binder and baking the mixture. The abrasive grains used are, for example, CBN (Cubic Boron Nitride) or diamond. The grinding wheel layer 312 comes into contact with the pin portion B, thereby grinding the outer periphery of the pin portion B.

[0022] The grinding wheel spindle 32 supports the grinding wheel 31 so that it can rotate around its axis. The grinding wheel spindle 32 is rotatably supported on the grinding wheel head 30 via a bearing (not shown). The axis of the grinding wheel spindle 32 coincides with the grinding wheel rotation axis BX, which is the axis of the grinding wheel 31. The direction of the grinding wheel rotation axis BX is parallel to the Z axis.

[0023] The grinding wheel rotation motor 33 is built into the grinding wheel head 30 coaxially with the grinding wheel spindle 32. The grinding wheel rotation motor 33 drives the grinding wheel spindle 32 to rotate about the grinding wheel rotation axis BX. As the grinding wheel spindle 32 rotates, the grinding wheel 31 is driven to rotate about the grinding wheel rotation axis BX.

[0024] The table movement motor 40 rotates a feed screw (not shown) to move the table 20 along the Z-axis direction. The table movement motor 40 has a table encoder 41. A signal from the table encoder 41 is fed back to a drive circuit 81. The Z-axis direction is also called the feed direction.

[0025] The wheel head movement motor 50 rotates a feed screw (not shown) to move the wheel head 30 along the X-axis direction. The wheel head movement motor 50 has a wheel head encoder 51. A signal from the wheel head encoder 51 is fed back to the drive circuit 82. The X-axis direction is also called the cutting direction of the grinding wheel 31.

[0026] Fig. 3 is a top view of the diameter measuring device 60. Fig. 4 is a side view of the diameter measuring device 60. The diameter measuring device 60 includes a first support portion 610, a second support portion 620, a third support portion 630, and a length measuring device 640. The diameter measuring device 60 measures the diameter of the journal portion A by bringing the length measuring device 640 into contact with the journal portion A of the eccentric shaft W. The first support portion 610 and the second support portion 620 support the journal portion A. The third support portion 630 supports a journal portion A2 that is different from the journal portion A.

[0027] The first support part 610 is provided below the journal part A. The first support part 610 includes a first movable plate 611, a second movable plate 612, and a threaded rod 621. The second support part 620 has the same configuration as the first support part 610.

[0028] The first movable plate 611 has a first inclined surface 613 and a first base 614. The second movable plate 612 has a second inclined surface 615 and a second base 616. The journal portion A is placed on the first inclined surface 613 and the second inclined surface 615. As shown in FIG. 4 , the first movable plate 611 and the second movable plate 612 are arranged so that the first inclined surface 613 and the second inclined surface 615 are symmetrical with respect to a plane that includes the axis Oa of the journal portion A and is perpendicular to the X-axis. The first base 614 is formed at the lower end of the first movable plate 611. The second base 616 is formed at the lower end of the second movable plate 612.

[0029] The threaded rod 621 is provided to penetrate the first base portion 614 and the second base portion 616 in the X-axis direction. The threaded rod 621 has a first threaded portion 622 and a second threaded portion 623. The first threaded portion 622 is a thread formed on the outer periphery of the threaded rod 621 on the -X-direction side of the center in the X-axis direction. The second threaded portion 623 is a thread formed on the outer periphery of the threaded rod 621 on the +X-direction side of the center in the X-axis direction. The first threaded portion 622 and the second threaded portion 623 have a mutually reverse thread relationship. The first threaded portion 622 screws into a first threaded hole 624 formed in the first base portion 614. The second threaded portion 623 screws into a second threaded hole 625 formed in the second base portion 616.

[0030] Because the first screw portion 622 and the second screw portion 623 have a mutually reverse thread relationship, when the threaded rod 621 is rotated around its rotation axis, the first movable plate 611 and the second movable plate 612 move toward or away from each other in the X-axis direction. Therefore, when the threaded rod 621 is rotated around its rotation axis, the journal portion A placed on the first inclined surface 613 and the second inclined surface 615 moves in the Y direction. Specifically, when the first movable plate 611 and the second movable plate 612 move toward each other, the journal portion A moves in the +Y direction, and when the first movable plate 611 and the second movable plate 612 move away from each other, the journal portion A moves in the -Y direction.

[0031] The third support part 630 supports the end part of the workpiece W from below. As shown in Fig. 3, the third support part 630 is provided below a journal part A2 different from the journal part A whose diameter is measured by the diameter measuring device 60.

[0032] The length measuring device 640 includes a fixed part 641 and a movable part 642. The fixed part 641 and the movable part 642 are arranged to sandwich the journal part A in the X-axis direction. The fixed part 641 is fixed so that a stator 643 at its tip contacts the journal part A. The movable part 642 is, for example, a differential transformer type length measuring device. The movable part 642 has a fixed housing 648 and a movable body 646. The fixed housing 648 is arranged so as to cover a portion of the movable body 646. The movable part 642 is arranged so that the movable body 646 can move or expand in the X-axis direction relative to the fixed housing 648. When the movable body 646 moves or expands in the X-axis direction relative to the fixed housing 648, the movable part 644 at the tip of the movable body 646 comes into contact with the journal part A. The mover 644 and the stator 643 contact the journal part A on a plane that is parallel to the horizontal plane and includes the axis Oa of the journal part A. The diameter of the journal part A is measured by the mover 644 and the stator 643 contacting both the left and right ends of the journal part A when viewed from the Z direction.

[0033] The control unit 70 controls the operation of the grinding device 100. The control unit 70 is electrically connected to the grindstone rotation motor 33, the diameter measuring device 60, and the drive circuits 81, 82, and 83.

[0034] 5 is a diagram illustrating the configuration of the control unit 70. The control unit 70 includes a CPU 71 and a storage unit 72.

[0035] The storage unit 72 stores programs and the like for operating the grinding apparatus 100. The storage unit 72 stores a pin portion machining program 721, workpiece information 722, grinding wheel information 723, a predetermined value of the diameter of the reference journal, and profile data. The profile data will be described later.

[0036] The pin portion machining program 721 is a program for grinding the pin portion B of the eccentric shaft W based on the diameter of the journal portion A measured by the diameter measuring device 60.

[0037] The workpiece information 722 is information about the eccentric shaft W, which is the workpiece to be ground. The workpiece information 722 is, for example, the eccentric stroke, the radius of the pin portion B before grinding, and the phase of the pin portion B relative to the journal portion A.

[0038] The grindstone information 723 is information relating to the grindstone 31. The grindstone information 723 is, for example, the radius of the grindstone 31.

[0039] The CPU 71 executes a program stored in the storage unit 72 to function as a deviation amount calculation unit 711, a grindstone position calculation unit 712, and an operation control unit 713. Some or all of these functional units may be realized by circuits.

[0040] The deviation amount calculation unit 711 calculates the deviation amount S using the diameter of the journal portion A measured by the diameter measuring device 60 and the diameter of the reference journal. The calculation of the deviation amount S in the deviation amount calculation unit 711 will be described later.

[0041] The grindstone position calculation unit 712 calculates the position of the grindstone 31 when executing the pin portion machining program 721. The grindstone position calculation unit 712 calculates the distance T between the spindle rotation axis AX and the grindstone rotation axis BX using the deviation S calculated by the deviation amount calculation unit 711, the eccentric stroke, the radius of the pin portion B before grinding, the radius of the grindstone 31 contained in the grindstone information 723, and the phase of the spindle 22 given as a drive command to the spindle rotation motor 24. The calculation of the distance T by the grindstone position calculation unit 712 will be described later.

[0042] The operation control unit 713 uses the profile data stored in the memory unit 72 to control the phase of the spindle 22 and the position of the grinding wheel 31 relative to the pin portion B. The operation control unit 713 controls the rotation speed of the grinding wheel rotation motor 33, thereby controlling the rotation speed of the grinding wheel 31. The operation control unit 713 outputs drive commands to the drive circuits 81, 82, and 83.

[0043] The drive circuit 81 controls the operation of the table moving motor 40 in response to a command from the operation control unit 713. The drive circuit 82 controls the operation of the wheel head moving motor 50 in response to a command from the operation control unit 713. The drive circuit 83 controls the operation of the spindle rotating motor 24 in response to a command from the operation control unit 713.

[0044] 6 is a process diagram of grinding the pin portion B of the eccentric shaft W by the grinding device 100. First, in step S10 of FIG. 6, the diameter of the journal portion A is measured by the diameter measuring device 60. The measured diameter of the journal portion A is stored in the memory unit 72.

[0045] Next, in step S20 of FIG. 6, the deviation amount S is calculated by the deviation amount calculation unit 711.

[0046] FIG. 7 is a diagram illustrating the deviation S calculated by the deviation calculation unit 711. In FIG. 7, a journal portion A of the eccentric shaft W and a reference journal M are supported by the V-block 232. The reference journal M is a virtual journal whose axis Om coincides with the spindle rotation axis AX when supported by the V-block 232. In this embodiment, the diameter of the reference journal M is smaller than the diameter of the journal portion A. The deviation S is the distance between the axis Oa of the journal portion A and the axis Om of the reference journal M when the journal portion A and the reference journal M are supported by the same V-block 232. In other words, the deviation S is the distance between the axis Oa of the journal portion A and the spindle rotation axis AX. The deviation calculation unit 711 calculates the deviation S using the diameter of the reference journal M and the diameter of the journal portion A measured by the diameter measuring device 60. As shown in FIG. 7, when the angle of the V-groove 237 of the V-block 232 is 90°, the diameter of the reference journal M is X, and the diameter of the journal part A measured by the diameter measuring device 60 is Y, the deviation S is calculated as Y / √2-X / √2.

[0047] Next, in step S30 of FIG. 6, the grindstone position calculation unit 712 calculates the distance T between the spindle rotation axis AX and the grindstone rotation axis BX.

[0048] FIG. 8 is a diagram illustrating the calculation of the distance T between the spindle rotation axis AX and the grinding wheel rotation axis BX by the grinding wheel position calculation unit 712. The phase α shown in FIG. 8 is the angle between the Y axis and a line connecting the spindle rotation axis AX and the axis Oa of the journal portion A. The phase α is equal to the phase of the spindle 22. The phase α is set to 0° when the axis Oa of the journal portion A is located directly above the spindle rotation axis AX. The eccentric shaft W is fixed to the V-block 232 so that when the phase α is 0°, the axis Ob of the pin portion B is located directly above the axis Oa of the journal portion A and the spindle rotation axis AX. The angle ap shown in FIG. 8 is the angle between the line connecting the spindle rotation axis AX and the axis Oa of the journal portion A and the line connecting the spindle rotation axis AX and the grinding wheel rotation axis BX, and is calculated by subtracting 270° from the phase α.

[0049] The distance T between the spindle rotation axis AX and the grinding wheel rotation axis BX is calculated using the following formulas (1) and (2): where d is the eccentric stroke, rb is the radius of the pin portion B, and R is the radius of the grinding wheel 31. β is the angle formed by the line connecting the spindle rotation axis AX and the grinding wheel rotation axis BX and the line connecting the grinding wheel rotation axis BX and the axis Ob of the pin portion B.

[0050] (S+d)×sinap=(rb+R)×sinβ...Equation (1) T=(S+d)×cosap+(rb+R)×cosβ...Equation (2)

[0051] In the above formula (1), the deviation amount S, the eccentric stroke d, the angle ap, the radius rb of the pin portion B, and the radius R of the grinding wheel 31 are known, so the angle β can be calculated. The distance T can be calculated by substituting the angle β obtained in formula (1) into formula (2). Therefore, the value of the distance T can be obtained when the phase α takes any value. In this specification, data that combines the value of the phase α and the value of the distance T corresponding to each phase α is called profile data. The profile data represents the correspondence relationship between the phase α of the spindle 22 and the position of the grinding wheel 31. The profile data is stored in the memory unit 72.

[0052] 6, the CPU 71 executes the pin portion machining program 721 to grind the pin portion B of the eccentric shaft W. By executing the pin portion machining program 721, the operation control unit 713 uses the profile data stored in the storage unit 72 to control the phase α of the spindle 22 and the position of the grinding wheel 31 relative to the pin portion B.

[0053] 9 to 12 are diagrams illustrating the control of the position of the grinding wheel 31 relative to the phase α of the spindle 22 and the pin B by the motion control unit 713. FIGS. 9 to 12 are schematic diagrams of the grinding wheel 31 and the eccentric shaft W projected onto the XY plane. The grinding point Q shown in FIGS. 9 to 12 is the point at which the grinding wheel 31 grinds the pin B. The eccentric shaft W is fixed to a V-block 232 (not shown) so that the axis Ob of the pin B is positioned directly above the axis Oa of the journal A and the spindle rotation axis AX when the phase α is 0°. The motion control unit 713 controls the feed motion of the grinding wheel 31 so that the distance (rb+R) between the axis Ob of the pin B and the grinding wheel rotation axis BX remains constant regardless of the phase α. Here, the feed motion of the grinding wheel 31 refers to the movement of the wheel head 30 in a direction intersecting the spindle rotation axis AX. Hereinafter, the negative direction of the X axis will be referred to as the forward feed direction of the grinding wheel 31, and the positive direction of the X axis will be referred to as the backward feed direction of the grinding wheel 31.

[0054] As shown in Figure 9, when the phase α is 270°, the axis Ob of the pin portion B is located on the line connecting the spindle rotation axis AX and the grinding wheel rotation axis BX, and is located further in the backward feed direction than the spindle rotation axis AX. The grinding point Q is located on the line connecting the spindle rotation axis AX and the grinding wheel rotation axis BX. In this case, the distance T is maximized. When the operation control unit 713 controls the spindle 22 so that the phase α is 270°, it controls the feed operation of the grinding wheel 31 so that the grinding wheel rotation axis BX is at the most backward position in the backward feed direction.

[0055] 10, when the phase α is 0°, the axis Ob of the pin portion B is at a position eccentric to the uppermost position relative to the spindle rotation axis AX. In this case, the distance T is smaller than when the phase α is 270°. When the operation control unit 713 controls the spindle 22 so that the phase α is 0°, it controls the feed operation of the grinding wheel 31 so that the grinding wheel rotation axis BX is at a position further forward in the forward feed direction than when the phase α is 270°.

[0056] As shown in Figure 11, when the phase α is 90°, the axis Ob of the pin portion B is located on the straight line connecting the spindle rotation axis AX and the grinding wheel rotation axis BX, and is located further in the forward feed direction than the spindle rotation axis AX. The grinding point Q is located on the straight line connecting the spindle rotation axis AX and the grinding wheel rotation axis BX. In this case, the distance T is minimum. When the operation control unit 713 controls the spindle 22 so that the phase α is 90°, it controls the feed operation of the grinding wheel 31 so that the grinding wheel rotation axis BX is at the most advanced position in the forward feed direction.

[0057] 12, when the phase α is 180°, the axis Ob of the pin portion B is at a position eccentric to the lowest position relative to the spindle rotation axis AX. In this case, the distance T is greater than when the phase α is 90°. When the operation control unit 713 controls the spindle 22 so that the phase α is 180°, it controls the feed operation of the grinding wheel 31 so that the grinding wheel rotation axis BX is at a position further back in the backward feed direction than when the phase α is 90°.

[0058] In this manner, the operation control section 713 controls the phase α of the main spindle 22 and the position of the grindstone 31 relative to the pin B, whereby the pin B of the eccentric shaft W is ground.

[0059] According to the grinding apparatus 100 described above, the deviation calculation unit 711 calculates the deviation S, which is the distance between the axis Oa of the journal portion A and the spindle rotation axis AX, based on the diameter of the journal portion A measured by the diameter measuring device 60. Then, the grindstone position calculation unit 712 calculates the distance T between the spindle rotation axis AX and the grindstone rotation axis BX from the deviation S, the eccentric stroke d, the phase α of the spindle 22, the radius rb of the pin portion B, and the radius rb of the grindstone 31. Profile data representing the correspondence between the phase α of the spindle 22 and the distance T is stored in the storage unit 72. Then, the operation control unit 713 uses the profile data to control the phase of the spindle 22 and the position of the grindstone 31 relative to the pin portion B, thereby grinding the pin portion B of the eccentric shaft W. Therefore, even if there is a processing error in the diameter of the journal portion A and the axis Oa of the journal portion A is deviated from the spindle rotation axis AX, the position of the grinding wheel 31 when grinding the pin portion B is calculated taking into account the amount of deviation S, which is the distance between the axis Oa of the journal portion A and the spindle rotation axis AX. Therefore, the grinding device 100 can grind the pin portion B with high precision even if there is a processing error in the diameter of the journal portion A.

[0060] B. Other Embodiments: (B-1) In the above embodiment, the diameter of the reference journal M may be larger than the diameter of the journal portion A. In other words, the deviation amount S may be a negative value.

[0061] (B-2) In the above embodiment, the diameter measuring device 60 may be a device that measures the diameter of the journal portion A by optical measurement or the like without contacting the journal portion A. Furthermore, the diameter measuring device 60 may be provided on the bed 10.

[0062] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0063] 10...bed, 20...table, 21...headstock, 22...spindle, 23...chuck, 24...spindle rotation motor, 25...spindle encoder, 26...tailstock, 27...center, 30...grinding wheel head, 31...grinding wheel, 32...grinding wheel spindle, 33...grinding wheel rotation motor, 40...table movement motor, 41...table encoder, 50...grinding wheel head movement motor, 51...grinding wheel head encoder, 60...diameter measuring device, 70...control unit , 71...CPU, 72...storage unit, 81...drive circuit, 82...drive circuit, 83...drive circuit, 100...grinding device, 231...bracket, 232...V-block, 234...positioning block, 235...clamp arm, 236...recess, 237...V-groove, 238...rotation pin, 239...cylinder rod, 240...long hole, 241...pin, 242...piston, 243...claw, 250...clamp mechanism, 3 11...core, 312...grindstone layer, 610...first support portion, 611...first movable plate, 612...second movable plate, 613...first inclined surface, 614...first base portion, 615...second inclined surface, 616...second base portion, 620...second support portion, 621...threaded rod, 622...first screw portion, 623...second screw portion, 624...first screw hole, 625...second screw hole, 630...third support portion, 640...length measuring device, 641...fixed portion, 64 2...moving part, 643...stator, 644...moving part, 711...deviation amount calculation part, 712...grinding wheel position calculation part, 713...motion control part, 721...pin part machining program, 722...workpiece information, 723...grinding wheel information, A...journal part, B...pin part, Q...grinding point, W...eccentric shaft, AX...main spindle rotation axis, BX...grinding wheel rotation axis, M...reference journal, Oa...journal part axis, Ob...pin part axis

Claims

1. A grinding device for grinding a pin portion of an eccentric shaft including a journal portion and a pin portion having an axis that is eccentric from the axis of the journal portion by an eccentric stroke, a diameter measuring device for measuring the diameter of the journal portion; a V-block having a V-groove and supporting the journal portion by the V-groove; a clamping mechanism that fixes the journal portion to the V-groove; a main shaft to which the V-block is fixed and which rotates around a main shaft rotation axis; a grinding wheel head that is provided so as to be movable in a direction intersecting the spindle rotation axis and that rotatably supports a grinding wheel that grinds the pin portion; a deviation amount calculation unit that calculates a deviation amount, which is a distance between an axis of the journal portion and a rotation axis of the spindle, based on the diameter of the journal portion measured by the diameter measuring device; a grindstone position calculation unit that calculates the position of the grindstone from the deviation amount, the eccentric stroke, and the phase of the spindle; a storage unit that stores profile data that indicates a correspondence relationship between the phase of the spindle and the position of the grindstone; an operation control unit that controls the phase of the spindle and the position of the grindstone relative to the pin portion using the profile data; Grinding equipment.

2. The grinding device according to claim 1, The angle of the V-groove of the V-block is 90°, When the diameter of a reference journal having an axis coincident with the spindle rotation axis is X and the diameter of the journal portion measured by the diameter measuring device is Y, the deviation amount is calculated by Y / √2-X / √2. Grinding equipment.

3. 3. The grinding device according to claim 1 or 2, the grindstone position calculation unit calculates the position of the grindstone according to the diameter of the grindstone and the diameter of the pin portion; Grinding equipment.

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