JP2020062698A - Phase indexing method and grinding method - Google Patents

Abstract

To provide a phase indexing method which can shorten a processing time as a whole by efficiently measuring an outside diameter of a processed part of workpiece, and a grinding method.SOLUTION: A grinder 1 indexes a phase of a workpiece W by using a rotation angle of a spindle 12a at the contact detection of two points at an upper side and a lower side by a touch probe 40 having a tip detection part 41, and a position of the tip detection part 41, and acquires a pin diameter r1 being an outside diameter of an eccentric part Wa by a calculation based on a geometrical relationship between the eccentric part Wa and the tip detection part 41. By performing grinding processing by setting a rough grinding start diameter xs by using the pin diameter r1, a rapid feed distance becomes long, and a rough grinding distance becomes short, thus shortening a processing time as a whole.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a phase indexing method and a grinding method.

  Conventionally, a crankshaft as a work is rotated around a rotation axis center of a main shaft that coincides with the center of a journal, and a grindstone base that supports a grinding wheel is relatively moved in a cutting direction with respect to a work according to a rotation phase. A grinder that grinds a crank pin that is eccentrically eccentric is used (see, for example, Patent Document 1).

  In the processing of the crankshaft by such a grinder, the grinding modes such as air-polishing, rough-polishing, fine-polishing, and fine-grinding are sequentially executed after the rapid feed of the grindstone. The starting diameter of the rough grinding, that is, the feed position of the grinding stone head when starting the rough grinding after the air grinding, is set to the maximum value of the machining allowance of the crank pin in the pre-machining or the deflection caused by the bending or bending of the workpiece by the clamp. It is decided based on the maximum value of. This prevents the grinding wheel from interfering with the work during the fast-forwarding or the air-polishing, resulting in damage to the grinding wheel or burning.

JP, 9-160619, A

  However, in the above-described conventional technique, the rough grinding start diameter is set to be larger than the actual outer diameter of the crank pin to be processed, and the rough grinding feed is executed, so that the time required for the rough grinding becomes longer than necessary. There is a problem that On the other hand, if the rough grinding start diameter is set by using the accurate outer diameter of the crank pin, the time for rough grinding can be shortened, but a step for measuring the outer diameter of the crank pin is added in addition to phase indexing. Then, it may not lead to the reduction of the entire processing time, but rather may increase the processing time.

  It is an object of the present invention to provide a phase indexing method and a grinding method that can efficiently measure the outer diameter of a work piece of a workpiece and reduce the overall working time.

  The phase indexing method according to the present invention is applied to a grinding wheel head that relatively feeds in a first axial direction that intersects the rotation axis while rotating a work having a processed portion that is eccentric with respect to the rotation axis with a spindle. It is a method of indexing the phase of the work in a grinder that grinds the processed portion by bringing a supported grinding wheel into contact.

  Then, the phase indexing method includes one of an attaching step of attaching the work to the spindle, a tip detecting portion of a touch probe attached to the grindstone and the processed portion of the workpiece attached to the spindle. A plurality of relative movement steps for making the other stand by at a plurality of positions and approaching the other to the one, respectively, and a plurality of detecting a contact of the tip detection unit with the processed portion during each of the relative movement steps. Of the contact detection step, the phase of the work is indexed by using the rotation angle of the spindle and the position of the tip detection part at the time of contact detection at the plurality of locations, and the geometry of the processed part and the tip detection part. And a calculation step of calculating an outer diameter of the processed portion by a calculation based on a geometrical relationship.

  According to this method, after the contact detection of the processed portion at a plurality of positions using the touch probe, while determining the phase of the work using the rotation angle of the spindle and the position of the tip detection unit at the time of contact detection at a plurality of positions. Since the outer diameter of the processed part is calculated by calculation based on the geometrical relationship between the processed part and the tip detection part, the outside diameter of the processed part can be efficiently measured without performing a separate operation for measuring the outer diameter. This has an effect that the measurement result of the diameter can be obtained. By performing the grinding process using the measurement result of the outer diameter of the processed part, it is possible to reduce the total time from the phase indexing to the completion of the grinding process.

  Grinding method according to the present invention, after performing the phase indexing method, while fast-forwarding the grindstone head toward the workpiece, while feeding the grindstone bed at a slower speed after the fast-forward step. A grinding method for performing at least one grinding step of grinding the processed part, wherein the outer diameter of the processed part obtained in the calculation step is used to start the grinding step. There is a grinding start diameter setting step of setting the grinding wheel base feed position as a grinding start diameter.

  According to this method, the outer diameter of the work piece obtained in the calculation step is used to set the grindstone feed position at the start of the grinding step as the grinding start diameter. The grinding start diameter can be set smaller than when the maximum outer diameter of the processed portion is set as the grinding start diameter. Therefore, by increasing the rapid feed distance of the grindstone as the grinding start diameter becomes smaller, it is possible to achieve the effect of shortening the entire processing time.

It is a top view which shows the whole structure of the grinder which concerns on 1st Embodiment. It is a side view which shows the measuring device which concerns on 1st Embodiment. It is a front view showing a measuring device concerning a 1st embodiment. It is a block diagram which shows the CNC apparatus which concerns on 1st Embodiment. It is a flow chart which shows the whole flow of the grinding method concerning a 1st embodiment. It is a flowchart which shows the flow of the contact detection process which concerns on 1st Embodiment. It is the schematic diagram which looked at the measuring device and the workpiece | work in S21 of FIG. 6 from the axial center direction. It is the schematic diagram which looked at the measuring device and workpiece | work in S22 of FIG. 6 from the axial center direction. It is the schematic diagram which looked at the measuring device and the workpiece | work in S23 of FIG. 6 from the axial center direction. It is the schematic diagram which looked at the measuring device and workpiece | work in S24-S27 of FIG. 6 from the axial direction. It is the schematic diagram which looked at the measuring device and workpiece | work in S28-S29 of FIG. 6 from the axial center direction. It is the schematic diagram which looked at the measuring device and workpiece | work in S30 of FIG. 6 from the axial center direction. It is the schematic diagram which looked at the measuring device and workpiece | work in S31-S34 of FIG. 6 from the axial direction. It is the schematic diagram which looked at the measuring device and workpiece | work in S35 of FIG. 6 from the axial center direction. It is a schematic diagram which looked at a measuring device and a touch probe from the direction of an axis, and is an explanatory view for explaining a calculation process concerning a 1st embodiment. It is a schematic diagram which expands and shows an eccentric part and a touch probe in FIG. It is a flow chart which shows a flow of a grinding process concerning a 1st embodiment. It is a graph which shows the relationship between the elapsed time and a grindstone cutting position in the grinding process which concerns on 1st Embodiment. It is a flowchart which shows the flow of the contact detection process which concerns on 2nd Embodiment. It is the schematic diagram which looked at the measuring device and the workpiece | work in S123 of FIG. 19 from the axial center direction. It is the schematic diagram which looked at the measuring device and workpiece | work in S124-S127 of FIG. 19 from the axial center direction. It is the schematic diagram which looked at the measuring device and the workpiece | work in S130 of FIG. 19 from the axial center direction. It is the schematic diagram which looked at the measuring device and workpiece | work in S131-S134 of FIG. 19 from the axial center direction. It is a schematic diagram which looked at a measuring device and a touch probe from the direction of an axis, and is an explanatory view for explaining a calculation process concerning a 2nd embodiment.

Hereinafter, embodiments of a grinding machine for carrying out the phase indexing method and the grinding method of the present invention will be described with reference to the drawings.
(1. First embodiment)
(1-1. Overall structure of grinding machine 1)
The configuration of the grinding machine 1 of the first embodiment will be described with reference to FIG. FIG. 1 is a plan view showing the overall configuration of the grinding machine 1 according to the first embodiment. The grinder 1 is a grinder for processing the work W. The workpiece W is a shaft-shaped member and has an eccentric portion Wa that is a processed portion. The eccentric portion Wa is a portion centered on an axis eccentric to the rotation axis of the work W. In particular, the eccentric portion Wa has a cylindrical outer peripheral surface, and the central axis of the eccentric portion Wa is eccentric with respect to the rotation axis of the workpiece W.

  In the present embodiment, the work W is exemplified by a crankshaft. However, the work W is not limited to the crankshaft. The work W, which is a crankshaft, includes a crankpin as the eccentric portion Wa. In FIG. 1, for example, the crankshaft (workpiece W) includes four crankpins (eccentric parts Wa) that are the processed parts. The rotation axis of the crankshaft coincides with the center axis of the crank journal. The grinder 1 grinds the outer peripheral surface of the crank pin, which is the eccentric portion Wa, while rotating the work W around the C axis that is the rotation axis.

  The grinder 1 is exemplified by a wheel head traverse type. However, the table 1 may be applied to the grinding machine 1. The grinder 1 exemplifies a configuration including only one disc-shaped grinding wheel 17, but a configuration including two grinding wheels 17 can also be applied.

  The grinding machine 1 is configured to include a bed 11, a headstock 12, a chuck 13, a tailstock 14, a traverse base 15, a grinding wheel stand 16, a grinding wheel 17, a measuring device 18, a drive unit 20, and a CNC device 60. It

  The bed 11 is placed on the installation surface. A guide rail 11 a extending in the Z-axis direction is formed on the upper surface of the bed 11. A ball screw 11b extending in a direction parallel to the Z-axis direction, and a Z-axis feed motor 11c for rotationally driving the ball screw 11b are provided on the upper surface of the bed 11.

  The headstock 12 functions as a support device that rotatably supports the work W. The headstock 12 is provided on the upper surface of the bed 11 on the front side in the X-axis direction as the first axis direction and on the one end side (front end side) in the Z-axis direction. The headstock 12 includes a main spindle 12a that is rotatable about the C axis, a main spindle motor 12b that rotationally drives the main spindle 12a, and a main spindle encoder 12c that outputs the rotation phase of the main spindle motor 12b. The spindle 12a includes a spindle center 12d that supports the center of one end of the work W. The spindle center 12d is provided in the center of the spindle 12a and the spindle motor 12b on the inner diameter side, and may be non-rotatably provided on the spindle stock 12 via a support cylinder (not shown).

  The chuck 13 is provided on the end surface of the spindle 12a, and is rotationally driven by the spindle motor 12b. The chuck 13 holds the outer peripheral surface of one end of the work W. That is, the chuck 13 rotates together with the spindle 12a while rotatably supporting the work W.

  The tailstock 14 is located on the upper surface of the bed 11 at a position facing the headstock 12 in the Z-axis direction, that is, on the front side in the X-axis direction (lower side in FIG. 1) and the other side in the Z-axis direction ( It is provided on the left side of FIG. 1. The tailstock 14 includes a tailstock center 14 a that supports the center of the other end of the work W. The tailstock center 14a may be provided so as to rotate together with the work W, or may be provided so as to slide with respect to the work W without rotating.

  The traverse base 15 is provided on the guide rail 11a so as to be movable in the Z-axis direction. The traverse base 15 is fixed to the nut of the ball screw 11b, and moves in the Z-axis direction by driving the Z-axis feed motor 11c. A guide rail 15a is formed on the upper surface of the traverse base 15 and extends in the X-axis direction orthogonal to the Z-axis direction. On the upper surface of the traverse base 15, a ball screw 15b extending in a direction parallel to the X-axis direction, an X-axis feed motor 15c that rotationally drives the ball screw 15b, and an X-axis that outputs a rotation phase of the X-axis feed motor 15c. The encoder 15d is provided. Further, the traverse base 15 may be driven by a linear motor instead of being driven by the ball screw 15b and the X-axis feed motor 15c in the X-axis direction.

  The grinding wheel base 16 is provided on the guide rail 15a of the traverse base 15 so as to be linearly movable in the X-axis direction which is the cutting direction of the grinding wheel 17 with respect to the work W. The grindstone base 16 moves in the X-axis direction by the rotational drive of the X-axis feed motor 15c. The grindstone base 16 supports a disk-shaped grindstone wheel 17 as a tool so as to be rotatable about the Z axis. The grindstone base 16 is provided with a cover 16a that exposes a grinding portion of the grinding wheel 17 and covers other portions. Further, the grindstone base 16 includes a grindstone rotating motor 16b that rotationally drives the grindstone wheel 17, and an AE sensor 16c. The AE sensor 16 c detects an AE (Acoustic Emission) wave generated by the contact between the work W and the grinding wheel 17, and outputs a detection signal to the CNC device 60.

  The measuring device 18 is provided on the front surface (lower side in FIG. 1) of the whetstone 16 and is used for measuring the work W, specifically for indexing the phase and measuring the outer diameter of the eccentric portion Wa. The detailed configuration of the measuring device 18 will be described later.

  The drive unit 20 is a drive circuit that drives each of the above-described motors based on a control command from the CNC device 60, and includes a grindstone rotation motor drive circuit 21, an X-axis feed motor drive circuit 22, and a Z-axis feed. Motor drive circuit 23, a spindle motor drive circuit 24, and a touch probe motor drive circuit 25.

  The grindstone rotating motor drive circuit 21 rotationally drives the grindstone rotating motor 16b to rotate the grindstone wheel 17. The X-axis feed motor drive circuit 22 rotationally drives the X-axis feed motor 15c to move the grindstone base 16 in the X-axis direction which is the cutting direction of the grinding wheel 17 with respect to the workpiece W, and inputs the output of the spindle encoder 12c. Then, the X-axis feed motor 15c is feedback-controlled to output the position signal of the grinding wheel head 16 in the X-axis direction to the CNC device 60. The Z-axis feed motor drive circuit 23 rotationally drives the Z-axis feed motor 11c to move the traverse base 15 in the Z-axis direction. The spindle motor drive circuit 24 rotationally drives the spindle motor 12b, rotates the work W together with the spindle 12a around the C axis, inputs the output of the spindle encoder 12c and feedback-controls the spindle motor 12b, and sends the spindle motor 12b to the CNC device 60. 12 phase signals around the C-axis are output. The touch probe motor drive circuit 25 rotationally drives the touch probe motor 51 to rotate the first link member 31 of the parallel link mechanism 30 to change the attitude of the touch probe 40 and input the output of the link encoder 53. The touch probe motor 51 is feedback-controlled to output the phase signal φ of the first link member 31 to the CNC device 60.

(1-2. Detailed configuration of measuring device 18)
The detailed configuration of the measuring device 18 will be described with reference to FIGS. 2 and 3. The measuring device 18 is provided on the end surface of the grinding wheel base 16 adjacent to the grinding wheel 17. Here, in FIG. 2, the rotation axis of the grinding wheel 17 is Tc, and the rotation axis of the work W is Wc. The rotational axes Wc and Tc are separated from each other in the X-axis direction, and the plane passing through the rotational axes Wc and Tc is the XZ plane.

  The measuring device 18 includes a parallel link mechanism 30, a touch probe 40, and a touch probe driving device 50. As shown in FIG. 2, the parallel link mechanism 30 is provided on the end face of the grindstone 16 so as to be swingable around shaft centers 31c1 and 32c1 parallel to the rotation shaft center Wc of the work W. The parallel link mechanism 30 includes a first link member 31, a second link member 32, and a connecting member 33.

  The first link member 31 is rotatably provided on the end surface of the grindstone base 16 by a bearing (not shown). The rotation axis 31c1 of the first link member 31 is parallel to the rotation axis Wc of the workpiece W and is located above the XZ plane passing through the rotation axes Wc and Tc. The first link member 31 is formed in an elongated shape so as to become thinner from the base end toward the tip. As a result, the first link member 31 has rigidity corresponding to the moment generated with the swing. Therefore, the first link member 31 is suppressed from being flexibly deformed.

  The second link member 32 is rotatably provided on the end surface of the grindstone base 16 by a bearing (not shown). The rotation axis 32c1 of the second link member 32 is parallel to the rotation axis 31c1 of the first link member 31, and is located above the rotation axis 31c1 in the Y-axis direction as the second axis direction. The second link member 32 is formed in the same shape as the first link member 31. That is, the second link member 32 is formed in an elongated shape that becomes thinner from the base end toward the tip. As a result, the second link member 32 has a rigidity corresponding to the moment generated due to the swing, like the first link member 31. Therefore, the second link member 32 is suppressed from being flexibly deformed.

  The coupling member 33 is rotatably supported by a rotating shaft center 31c2 at the tip of the first link member 31 and a rotating shaft center 32c2 at the tip of the second link member 32 by a bearing (not shown). Here, the distance between the rotary shaft centers 31c2 and 32c2 of the connecting member 33 is equal to the distance between the rotary shaft center 31c1 of the first link member 31 and the rotary shaft center 32c1 of the second link member 32. Therefore, the quadrangle connecting the rotational axes 31c1, 32c1, 32c2, 31c2 is always a parallelogram in all postures. That is, the first link member 31 and the second link member 32 swing with respect to the wheel head 16 while always maintaining a parallel state. Therefore, the connecting member 33 always maintains the attitude extending in the Y-axis direction.

  The touch probe 40 is attached to the connecting member 33 of the parallel link mechanism 30 and includes a spherical tip detection unit 41. As the first link member 31 and the second link member 32 of the parallel link mechanism 30 swing, the touch probe 40 also swings with respect to the wheel head 16. At this time, the touch probe 40 attached to the connecting member 33 always maintains the same posture (a state extending in a predetermined direction) regardless of the position of the parallel link mechanism 30.

  Here, the touch probe 40 is provided so as to extend in a direction intersecting the linear movement direction (X-axis direction) of the grindstone base 16. More specifically, the touch probe 40 is provided so as to extend in the Y-axis direction, that is, in the direction orthogonal to the linear movement direction (X-axis direction) of the wheel head 16. That is, when the parallel link mechanism 30 swings, the touch probe 40 always maintains the attitude extending in the Y-axis direction.

  Further, since the touch probe 40 is attached to the connecting member 33, the locus 41a of the spherical tip detection unit 41 swings around the axis Pc parallel to the rotation axis Wc of the work W. That is, the tip detection unit 41 moves in an arc shape centered on the rotation axis Pc on the XY plane orthogonal to the rotation axis Wc (Z-axis direction) of the work W. In other words, the tip detection unit 41 moves two-dimensionally on the XY plane. In particular, the rotation axis P3 of the tip detection unit 41 is provided on a plane that passes through the rotation axis Tc of the grinding wheel 17 and the rotation axis Wc of the workpiece W and is parallel to the rotation axes Wc and Tc.

  As shown in FIG. 3, the touch probe drive device 50 includes a touch probe motor 51 and a speed reducer 52. The link encoder 53, the touch probe motor 51, and the speed reducer 52 are coaxially arranged and coincide with the rotation axis 31c1 of the first link member 31. Then, the rotation of the touch probe motor 51 is reduced by the speed reducer 52 to rotationally drive the first link member 31. That is, the drive of the touch probe motor 51 causes the first link member 31 to rotate around the rotation axis 31c1. The first link member 31 constitutes the parallel link mechanism 30 together with the second link member 32 and the connecting member 33, so that the second link member 32 and the connecting member 33 follow the first link member 31. As a result, the drive of the touch probe motor 51 causes the touch probe 40 to swing, and the output of the link encoder 53 is output to the CNC device 60 as the phase signal φ of the first link member 31 via the touch probe motor drive circuit 25. To do.

(1-3. Configuration of CNC device 60)
Next, the configuration of the CNC device 60 will be described with reference to FIG. FIG. 4 is a block diagram showing the CNC device 60 according to the first embodiment. The CNC device 60 is a computer numerical control device that issues a control command to the drive unit 20, and as shown in FIG. 4, an NC program storage unit 61, a data storage unit 63, a profile calculation unit 64, and a control unit 65. And a display unit 66.

  The NC program storage unit 61 is a storage area for storing the NC program, and stores, ie, stores, the NC program for processing the work W by inputting it from the outside. The NC program includes a code consisting of one letter of alphabet and a number following it, and one of the codes is a G code for processing the movement of the spindle and the setting of the coordinate system. The G code includes a code G00 indicating fast-forwarding, a code G01 indicating machining feeding, and G106 indicating profile calculation. The data storage unit 63 is a storage area that stores various data used for processing control.

  The profile calculation unit 64 calculates profile data based on the NC program. The profile data includes the rotation phase θ of the rotation axis Wc of the work W (for example, the angular position at 1 degree) and the movement position of the grinding wheel 17 corresponding to each rotation phase (the rotation axis Wc and the grinding wheel axis Tc. Is the point cloud data defining the inter-center distance xt) of.

  Then, the control unit 65 controls each drive circuit of the drive unit 20 based on the profile data. That is, the Z-axis feed motor drive circuit 23 rotationally drives the Z-axis feed motor 11c to move the traverse base 15 in the Z-axis direction, and the grinding wheel 17 is opposed to the crank pin that is the eccentric portion Wa. Further, the spindle motor drive circuit 24 rotationally drives the spindle motor 12b to rotate the work W together with the spindle 12a around the C axis. Further, based on the profile data, the spindle 12a, which is the rotation axis of the workpiece W, is rotated, and the X-axis feed motor drive circuit 22 rotationally drives the X-axis feed motor 15c to move the grindstone base 16 in the X-axis direction. To move. Then, the grindstone rotating motor drive circuit 21 rotationally drives the grindstone rotating motor 16b to rotate the grindstone wheel 17, thereby grinding the crank pin, which is the eccentric portion Wa.

  The control unit 65 also includes a position calculation unit 65a that calculates a position and a phase based on the encoder output of each unit, and a position data storage unit 65b that stores the position and phase data calculated by the position calculation unit 65a. The display unit 66 displays data such as the position of the grinding wheel head 16 and the phase of the spindle 12a stored in the position data storage unit 65b.

(1-4. Overall flow of grinding method)
Next, the overall flow of the method of grinding the eccentric portion Wa of the work W by the grinding machine 1 will be described with reference to FIG. The grinding method is executed by the control unit 65. First, in step 1 (hereinafter abbreviated as S1. The same applies to other steps), the controller 65 determines that the work W has been loaded into the grinder 1. If the work W has not been loaded (S1: No), the control unit 65 waits until it is loaded.

  When the work W is loaded (S1: Yes), the control unit 65 advances the spindle center 12d and the tailstock center 14a to the work W side in S2. Then, the work W is supported on both sides by the spindle center 12d and the tailstock center 14a. Subsequently, the control unit 65 closes the chuck 13 and holds the work W by the chuck 13 in S3. That is, the steps S2 to S3 are the attaching steps for attaching the work W to the spindle 12a. The work W is attached to the main shaft 12a such that the eccentric portion Wa is located immediately below the rotation axis Wc, and the deviation angle with respect to the position directly below the rotation axis Wc is referred to as the attachment deviation.

  Then, the control part 65 performs a contact detection process using the measuring device 18 in S4. That is, in the contact detecting step, one of the tip detecting portion 41 of the touch probe 40 attached to the grindstone 16 and the eccentric portion Wa of the work W attached to the spindle 12a is made to stand by at a plurality of places and the other is made to be one. It includes a plurality of relative movement steps for approaching each other and a plurality of detection steps for detecting that the tip detection unit 41 has contacted the processed portion Wa during each relative movement step. Particularly in the present embodiment, in the plurality of relative movement steps, the grindstone base 16 is stopped after the relative feed operation, the tip detection unit 41 of the touch probe 40 is made to stand by at a plurality of positions, and the spindle 12a is rotated so that the workpiece W is not moved. The processing parts Wa are brought close to the tip detecting parts 41, respectively. Details of the contact detection step (S4) will be described later.

  Subsequently, the control unit 65 executes the calculation step in S5 to calculate the phase of the work W and the radius r1 (hereinafter, also referred to as “pin diameter r1”) which is the outer diameter of the eccentric portion Wa. . That is, in the calculation step, the phase of the work W is indexed using the rotation angle of the spindle 12a and the position of the tip detection unit 41 when contact is detected at a plurality of points, and the eccentric portion Wa and the tip detection unit 41 are geometrically determined. The outer diameter of the eccentric portion Wa is obtained by calculation based on the relationship. Details of the calculation step (S5) will be described later.

  Subsequently, in S6, the control unit 65 executes the grinding process according to the NC program. Details of the grinding step (S6) will be described later. When the grinding process is completed, the controller 65 opens the chuck 13 in S7 and retracts the headstock 12 and tailstock 14 in S8. In this way, the support of the work W is released. Subsequently, the control unit 65 determines in S9 that the work W has been carried out. Then, the control unit 65 waits until the work W is carried out (S9: No), and returns if the work W is carried out (S9: Yes).

(1-5. Description of contact detection process)
The contact detection step of S4 in the grinding method shown in FIG. 5 will be described. In the present embodiment, the tip detection unit 41 of the touch probe 40 attached to the grindstone 16 is made to stand by at a plurality of points (two points of the upper contact position and the lower contact position), and the work W attached to the spindle 12a is eccentric. A plurality of (two times) relative movement steps of rotating the part Wa to approach the tip detection section 41 are executed, and it is detected that the tip detection section 41 contacts the eccentric section Wa during each relative movement step. A plurality of (twice) detection steps are executed.

  Hereinafter, the flow of the contact detection process in the present embodiment will be described in detail mainly with reference to the flowchart of FIG. 6 and with reference to FIGS. 7 to 14, the configuration of the measuring device 18 is simplified and shown. In the contact detection process, the measuring device 18 is used. As shown in FIG. 7, in the retracted posture in which the touch probe 40 is located at the upper end in the movement range, the control unit 65 advances the whetstone base 16 to the preliminary position (xt0) in S21. xt0 is the center distance between the rotation axis Wc and the grindstone axis Tc in the preliminary position. The retracted posture of the touch probe 40 is a posture in which the touch probe 40 does not interfere with the grinding by the grinding wheel 17. As the preliminary position, the grindstone base 16 is located behind the contact position (xt1) described later, that is, on the side farther from the work W.

  Subsequently, as shown in FIG. 8, in S22, the control unit 65 drives the touch probe motor 51 of the touch probe driving device 50 to move the touch probe 40 to the upper contact posture. In the upper contact posture, the center Pc of the tip detection unit 41 is located above the reference plane in the Y-axis direction with reference to the XZ plane including the reference line connecting the rotation axis Wc of the workpiece W and the grindstone axis Tc. They are located apart from each other by the set value y1. This upper contact posture is a posture for bringing the tip detection unit 41 of the touch probe 40 into contact with the eccentric portion Wa of the work W above the reference plane.

  Specifically, the inclination angle φ of the first link member 31 with respect to the vertical line is obtained from the relationship of the mathematical formula shown below. Here, as shown in FIGS. 9 and 10, x1 is the distance between the rotation axis Wc and the tip detection unit 41 in the X-axis direction, m is the length of the first link member 31, and xp is the rotation of the tip detection unit 41. The distance between the axis Pc and the rotation axis Tc of the grinding wheel 17 in the X axis direction, yp is the distance in the Y axis direction between the rotation axis Pc of the tip detection unit 41 and the rotation axis Tc of the grinding wheel 17, and xq is the first The X-axis direction distance between the tip of the link member 31 and the tip detection unit 41, yq is the Y-axis direction distance between the tip of the first link member 31 and the tip detection unit 41, and r1 is the radius of the eccentric portion Wa, as shown in FIG. (Pin diameter), r2 is 1/2 (half stroke) of the stroke of the center Wac of the eccentric portion, and R is the radius (probe radius) of the tip detection unit 41. The diagram on the upper left of FIG. 9 is an enlarged view of the periphery of the touch probe 40.

xt1 = x1 + xq + msinφ + xp ... [Equation 1-1]
x1 = −r2 sin θ3 + r1 + R ... [Equation 1-2]
y1 = −r2 cos θ3 [Equation 1-3]
y1 = yp + mcosφ−yq ... [Equation 1-4]
In the above [Equation 1-3] and [Equation 1-4], the angle φ is obtained so that y1 becomes equal, and the angle φ touch probe motor 51 is rotationally driven.

  Subsequently, as shown in FIG. 9, in S23, the control unit 65 causes the grindstone base 16 to move forward and stop at the contact position (xt1), and waits for the tip detection unit 41 of the touch probe 40 at the upper contact position. Let xt1 is the center distance between the rotation axis Wc and the grindstone axis Tc at the contact position. That is, since x1 is obtained from [Equation 1-2], xt1 is obtained by substituting the obtained value of x1 into [Equation 1-1]. In the following description, the position of the tip detection unit 41 when the touch probe 40 is in the upper contact posture and the grindstone base 16 is in the contact position (xt1) is called the upper contact position, and the touch probe 40 is in the lower contact position. The position of the tip detection unit 41 when the whetstone 16 is in the attitude and in the contact position (xt1) is referred to as a lower contact position. The lower contact posture is a posture for bringing the tip detection unit 41 of the touch probe 40 into contact with the eccentric portion Wa of the work W below the reference plane.

  Subsequently, as shown in FIG. 10, in S24, the control unit 65 causes the spindle motor 12b to rotate forward (clockwise in FIG. 10). Then, in S25, the control unit 65 determines whether or not the eccentric portion Wa of the workpiece W mounted on the main shaft 12a and rotating in the forward direction comes into contact with the tip detection unit 41 of the touch probe 40 standing by at the upper contact position. To do. The work W is rotated forward until it comes into contact (S25: No).

  Then, in the case of contact (S25: Yes), as shown in FIG. 10, the control unit 65 stops the spindle motor 12b in S26, and based on the output of the spindle encoder 12c at that time, the control of the spindle motor drive circuit 24 is stopped. The phase θ of the spindle 12 obtained from the output is stored. The position calculation unit 65a calculates the upper actual movement amount θ4, which is the difference between the phase of the main shaft 12 before S24 and the phase of the main shaft 12 at S24, and stores it in the position data storage unit 65b. The actual upper movement amount θ4 is equal to the upper movement amount set value θ3 under ideal conditions in which the radius of the eccentric portion Wa does not vary and the mounting angle of the work W does not deviate. Further, in S27, based on the position xt1 of the grindstone 12 obtained from the output of the X-axis feed motor drive circuit 22 and the mathematical expression [1-1] stored in the position calculation unit 65a, the probe position, that is, the rotation axis. The inter-center distance x1 between the heart Wc and the tip detection unit 41 of the touch probe 40 is calculated and stored in the position data storage unit 65b.

  Subsequently, as shown in FIG. 11, in S28, the control unit 65 retracts the wheel head 16 to the preliminary position (xt0). Further, in S29, the control unit 65 drives the touch probe motor 51 of the touch probe driving device 50 to move the touch probe 40 to the lower contact posture. In the lower contact posture, with the XZ plane as a reference, the tip detection unit 41 is located below the reference plane at a position separated by the set value y1.

  Then, as shown in FIG. 12, in S30, the control unit 65 causes the grindstone base 16 to move forward to stop at the contact position (xt1), and causes the tip detection unit 41 of the touch probe 40 to move to the lower contact position. Make it stand by. Subsequently, as shown in FIG. 13, in S31, the control unit 65 causes the spindle motor 12b to rotate in the reverse direction (counterclockwise rotation in FIG. 13). Then, in S32, the control unit 65 determines whether or not the eccentric portion Wa of the workpiece W mounted on the spindle 12a and rotating in the reverse direction contacts the tip detection unit 41 of the touch probe 40 standing by at the lower contact position. judge. The work W is reversely rotated until it comes into contact (S32: No).

  Then, in the case of contact (S32: Yes), as shown in FIG. 13, the control unit 65 stops the spindle motor 12b in S33, and outputs the output of the spindle motor drive circuit 24 based on the output of the spindle encoder 12c at that time. The phase θ of the spindle 12 obtained from the above is stored. The actual vertical movement amount θ2, which is the difference between the phase of the spindle 12 in S26 and the phase of the spindle 12 in S33, is calculated by the position calculator 65a and stored in the position data storage 65b. The actual vertical movement amount θ2 is equal to the vertical movement amount set value θ1 under ideal conditions in which the radius of the eccentric portion Wa does not vary and the mounting angle of the work W does not deviate. Further, in S34, the current position xt1 of the grindstone 12 and the probe position calculated from Equation [1-1], that is, the X-axis direction distance x1 from the rotation axis Wc of the tip detection unit 41, and X−. The Y-axis direction distance y1 from the Z plane is stored. Subsequently, as shown in FIG. 14, the control unit 65 retracts the grindstone base 16 and shifts the touch probe 40 to the retracted posture in S35. With that, the process ends. Note that S23 to S24 and S30 to S31 correspond to a plurality of relative movement steps in the present invention, and S25 and S32 correspond to a plurality of detection steps.

(1-6. Description of calculation process)
The calculation step of S5 in the flowchart of FIG. 5 will be described in detail with reference to FIGS. 15 and 16. FIG. 15 is a schematic view of the measuring device and the touch probe in which the calculation process is performed as seen from the axial direction, and FIG. 16 is an enlarged schematic view of the eccentric portion Wa and the touch probe 40 in FIG. 15 and 16, the actual position of the eccentric portion Wa is shown by a solid line, and the set position (position under ideal conditions) is shown by a broken line. Further, as shown in FIG. 16, when the eccentric portion Wa and the tip detecting portion 41 of the touch probe 40 are in contact with each other, an eccentric portion center Wac, a center Pc of the spherical tip detecting portion 41, and a vertical line passing through Wac are shown. A right triangle having an apex at the intersection point WP with the horizontal line passing through Pc is formed. In this right triangle, the hypotenuse Wac-Pc is a, the base Pc-WP is b, and the height Wac-WP is c.

  Further, the radius (pin diameter) of the eccentric portion Wa, which is a crank pin, is r1, the half stroke, which is 1/2 of the stroke of the eccentric portion center Wac that rotates around the work shaft center Wc, is r2, and the spherical tip detecting portion 41. Let R be the probe radius, which is the radius of.

First, the measurement deviation angle θ5 due to the variation in pin diameter is calculated by the following [Formula 2-1] using the vertical movement amount setting value θ1 and the vertical movement amount.
θ5 = (θ1−θ2) / 2 ... [Equation 2-1]
Further, the phase θ7 of the eccentric center Wac at the upper contact position with respect to the reference line parallel to the X axis is obtained by the following [Formula 2-2].
θ7 = 270−θ3 + θ5 [Equation 2-2]
In [Equation 2-2], the X-axis direction position x1 of the tip detection unit 41 of the touch probe 40 is the same at the upper contact position and the lower contact position, and the distance y1 from the reference line parallel to the X-axis. Since it is the same, it is assumed that the eccentric portion Wa is symmetrical between the upper contact position and the lower contact position with respect to the reference line.

Next, the pin diameter r1 is calculated using the measurement result of the vertical actual movement amount θ2 at the upper contact position or the lower contact position. Each of a, b, and c is represented by the following [Formula 2-3] to [Formula 2-5].
a = R + r1 [Equation 2-3]
b = x− (r2 * cos θ7) [Equation 2-4]
c = (r2 * sin θ7) −y ... [Equation 2-5]

Here, according to the Pythagorean theorem, the following [Formula 2-6] is established between a, b, and c.
a ² = b ² + c ² ... [Equation 2-6]
Therefore, a can be obtained from [Equation 2-5], and the pin diameter r1 can be obtained from [Equation 2-2].

Next, the mounting deviation angle θ6 of the work W with respect to the spindle 12a is obtained. The mounting deviation angle θ6 is an angle of the center Wac of the eccentric portion with reference to the position directly below the rotation axis Wc. The mounting deviation angle θ6 is obtained by the following [Equation 2-7] using the upper side movement amount set value θ3, the upper side actual movement amount θ4, and the measurement deviation angle θ5 due to the variation in the pin diameter.
θ6 = θ3-θ4-θ5 [Equation 2-7]

(1-7. Description of grinding process)
The grinding step of S6 in the flowchart of FIG. 5 will be described in detail with reference to FIGS. 17 and 18. FIG. 17 is a flowchart showing the flow of the grinding process, and FIG. 18 is a graph showing the relationship between the elapsed time and the grinding wheel cutting position in the grinding process.

  First, the control unit 65 sets the rough grinding start diameter in S61. The rough-polishing start diameter xs is a length that represents the cutting position of the grindstone when the rough-polishing is started in S65, and is the distance between the rotation axis Wc and the tip of the grinding wheel 17 at the start of the rough-grinding. The roughing start diameter xs is set to the sum of the pin diameter r1 obtained in the calculation step of S5 and the maximum deflection value fmax of the work W. In other words, it is expressed as the rough grinding start diameter xs = r1 + fmax. The rough grinding start diameter xs corresponds to the grinding start diameter of the present invention, and S61 is the value when the grinding is started by using the pin diameter r1 which is the outer diameter of the processed portion obtained in the calculation step S5 of the present invention. This corresponds to a grinding start diameter setting step of setting the feed position of the wheel head 16 as a grinding start diameter.

  Next, the control unit 65 performs phase correction in S62. That is, the phase of the work W is corrected by rotating the main shaft 12a by the deviation angle θ6 obtained in the calculation step of S5. When θ6 is a positive value, the spindle 12a is rotated in the positive direction (clockwise), and when it is a negative value, the spindle 12a is rotated in the opposite direction (counterclockwise). It should be noted that S62 corresponds to a phase correction step of correcting the phase by rotating the main shaft 12a by a shift angle θ6 calculated based on the phase of the work W calculated in the calculation step S5 in the present invention.

  Next, the control part 65 fast-forwards the grindstone base 16 in S63. That is, the control unit 65 rotationally drives the X-axis feed motor 15c at a rotation speed corresponding to the rapid feed speed V1, and the position x2 of the tip of the grinding wheel 17 in the X-axis direction in the X-axis direction is set to the workpiece W side. Move to the position corresponding to the starting diameter. In addition, S63 corresponds to the fast-forwarding step of fast-forwarding the grindstone base 16 toward the workpiece W in the present invention.

  Then, the control part 65 performs air-laboratory in S64. That is, the control unit 65 starts rotation of the spindle motor 12b and the grindstone rotating motor 16b, and also rotationally drives the X-axis feeding motor 15c at a rotation speed corresponding to the air-velocity feeding speed V2 to move the grindstone base 16 to the X-axis. In the direction to the work W side to a position corresponding to the rough grinding start diameter. The air velocity V2 is lower than the fast velocity V1. Therefore, V2 <V1.

  Next, the control unit 65 performs rough polishing in S65. That is, the control unit 65 rotationally drives the X-axis feed motor 15c at a rotation speed corresponding to the rough-grinding feed speed V3 to move the grindstone base 16 in the X-axis direction such that the position x2 of the tip of the grinding wheel 17 moves to the work W side. The main shaft motor 12b and the grindstone rotating motor 16b are rotated while being moved until the diameter reaches the fine polishing start diameter to perform rough polishing. The rough-working feed speed V3 is lower than the blank-working feed speed V2. Therefore, V3 <V2 <V1. Note that at least one grinding process in which the rough polishing in S65 grinds the eccentric part Wa, which is the part to be processed, while feeding the wheel head 16 at a speed slower than in the fast-feed process S63 after the fast-feed process S63 in the present invention, Equivalent to.

  Subsequently, the control unit 65 performs precision polishing in S66. That is, the control unit 65 rotationally drives the X-axis feed motor 15c at a rotation speed corresponding to the precision polishing feed speed V4, and moves the grindstone head 16 toward the workpiece W in the X axis direction until the precision polishing end diameter is reached. Meanwhile, the spindle motor 12b and the grindstone rotating motor 16b are rotated to perform precision polishing. The precision polishing feed speed V4 is lower than the rough polishing feed speed V3. Therefore, V4 <V3 <V2 <V1.

  Further, the control unit 65 performs fine grinding in S67. That is, the control unit 65 rotationally drives the X-axis feed motor 15c at a rotation speed corresponding to the micro-grinding feed speed V5 to move the grindstone head 16 toward the workpiece W in the X-axis direction until the micro-milling end diameter is reached. Meanwhile, the main shaft motor 12b and the grindstone rotating motor 16b are rotated to perform fine grinding. The fine laboratory feed speed V5 is lower than the fine laboratory feed speed V4. Therefore, V5 <V3 <V2 <V1.

  Then, when the fine grinding in S67 is completed, the control unit 65 performs spark out in S68. That is, the control unit 65 performs spark out for a predetermined time set by a timer in a state in which the X-axis feed motor 15c is stopped to rotate and the grindstone base 16 is stopped to be fed. Subsequently, in S69, the control unit 65 rotationally drives the X-axis feed motor 15c to retract the grindstone base 16 from the work W in the X-axis direction, and stops the rotation of the spindle motor 12b and the grindstone rotation motor 16b. , And ends all processing.

  Next, regarding the relationship between the grindstone cutting position and the processing time, an example based on the first embodiment and a comparative example based on the related art will be compared with reference to FIG. As described above, the roughing start diameter xs1 of the embodiment shown in the upper part of FIG. 18 is the sum of the pin diameter r1 which is the measured value of the radius of the eccentric portion Wa obtained in the calculation step and the maximum deflection fmax of the workpiece W. Is set. That is, it is expressed as the rough polishing start diameter xs1 = r1 + fmax in the example.

  On the other hand, in the rough grinding start diameter xs0 of the comparative example shown in the lower part of FIG. 18, the sum of the maximum value rmax of the radius of the eccentric portion Wa and the maximum deflection wmax of the work W is set. In other words, it is expressed as the rough grinding start diameter xs0 = rmax + fmax of the comparative example. Here, since r1 <rmax, the rough polishing start diameter xs1 of the example is smaller than the rough polishing start diameter xs0 of the comparative example (xs1 <xs0).

  Therefore, in the example, the rapid feed distance in S63 is lengthened and the rough grinding distance in S65 is shortened by the difference (= xs0−xs1) between the rough grinding start diameter xs0 of the comparative example and the rough grinding start diameter xs1 of the example. can do. Therefore, in the example, the entire processing time is shortened as compared with the comparative example without affecting the processing accuracy.

(1-8. Summary)
As described above, according to the phase indexing method of the present embodiment, the contact angle of the spindle 12a and the tip detection unit at the time of contact detection at a plurality of positions after the contact detection of the processed portion at a plurality of positions using the touch probe. The position of 41 is used to determine the phase of the work W, and the pin diameter r1 that is the outer diameter of the eccentric portion Wa is calculated by calculation based on the geometrical relationship between the eccentric portion Wa that is the workpiece and the tip detection portion 41. Since it is obtained, there is an effect that the measurement result of the outer diameter of the eccentric portion Wa can be efficiently obtained without separately performing the operation for measuring the outer diameter.

  In the calculation step S5, the first straight line Pc-WP parallel to the X-axis direction passing through the center Pc of the tip detection unit 41 and the center of the eccentric portion Wa in the state where the tip detection unit 41 and the eccentric portion Wa are in contact with each other. A second straight line Wac-WP passing through Wac and parallel to the Y-axis direction intersecting the X-axis direction and the rotation axis Wc, and a third straight line passing through the center Wac of the eccentric portion Wa and the center Pc of the tip detection unit 41. The pin diameter r1 which is the outer diameter of the eccentric portion Wa is obtained based on the geometrical relationship of the right triangle formed by Wac-Pc. Therefore, a highly accurate measurement result of the pin diameter r1 can be efficiently obtained in a series of operations accompanying the phase indexing of the work W.

  Further, according to the grinding method of the present embodiment, by using the pin diameter r1 which is the outer diameter of the eccentric portion Wa obtained in the calculation step S5, the grinding stone head feeding position at the start of rough polishing is set as the rough polishing start diameter xs. Since the setting is performed, the roughing start diameter xs can be set smaller than the case where the maximum outer diameter of the eccentric portion Wa determined by the accuracy in the pre-processing of the work W is set as the roughing start diameter xs. Therefore, by increasing the rapid feed distance of the grindstone 16 and shortening the rough grinding distance as the rough grinding start diameter xs becomes smaller, it is possible to shorten the entire processing time. When the same work W has a plurality of eccentric portions Wa, it is not necessary to obtain the pin diameter r1 for each eccentric portion Wa, and the pin diameter r1 obtained for one eccentric portion Wa is It can be used for grinding other eccentric parts Wa.

(2. Second embodiment)
Next, a second embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the contact detection process and the calculation process are different from those in the first embodiment, and the device configuration and other processes are the same as those in the first embodiment, and therefore the description thereof will be omitted. The same members are designated by the same reference numerals and detailed description thereof will be omitted.

(2-1. Contact detection process)
The contact detection process in the present embodiment will be described centering on the flowchart of FIG. 19 and also appropriately referring to FIGS. 7, 8, 11, 14, and 20 to 23. In the present embodiment, the eccentric portion Wa of the work W attached to the spindle 12a is made to stand by at two positions, the upper contact position and the lower contact position, and the tip detection unit 41 of the touch probe 40 attached to the grindstone 16 is eccentric. A plurality of (twice) detection steps of executing a plurality of (two times) relative movement steps of approaching the portion Wa and detecting that the tip detection unit 41 contacts the eccentric portion Wa during each of the relative movement steps. To execute.

  That is, in the present embodiment, in the retracted posture in which the touch probe 40 is located at the upper end in the movement range, the control unit 65 advances the grindstone base 16 to the preliminary position (xt0) in S121 (see FIG. 7 of the first embodiment). ). Subsequently, in S122, the control unit 65 drives the touch probe motor 51 of the touch probe driving device 50 to move the touch probe 40 to the upper contact posture (see FIG. 8 of the first embodiment).

  Then, as shown in FIG. 20, the control unit 65 makes a positive rotation (clockwise rotation in FIG. 20) of the spindle motor 12b by an angle θ3 as an upper movement amount set value, and then stops at S123. The eccentric part Wa of the work W is made to stand by. Next, in S124, the control unit 65 rotationally drives the X-axis feed motor 15c to feed the grindstone base 16 forward. Then, in S125, the control unit 65 determines whether or not the tip detection unit 41 of the touch probe 40 and the eccentric portion Wa of the work W are in contact with each other. The grinding wheel head 16 is moved forward until it comes into contact (S125: No).

  Then, in the case of contact (S125: Yes), as shown in FIG. 21, the control unit 65 stops the X-axis feed motor 15c in S126, and the upper measured phase obtained from the output of the spindle encoder 12c at that time. Memorize Further, in S127, the probe position, that is, the center distance x1 between the rotation axis Wc and the tip detection unit 41 of the touch probe 40 is stored.

  Subsequently, in S128, the control unit 65 retracts the grindstone base 16 to the preliminary position (xt0). Further, in S129, the control unit 65 drives the touch probe motor 51 of the touch probe driving device 50 to move the touch probe 40 to the lower contact posture (see FIG. 11 of the first embodiment). Subsequently, as shown in FIG. 22, in S130, the control unit 65 reversely rotates the spindle motor 12b by the angle θ1 which is the vertical movement amount setting value (counterclockwise rotation in FIG. 22), and at this position, the workpiece is rotated. The eccentric part Wa of W is made to stand by.

  Next, in S131, the control unit 65 rotationally drives the X-axis feed motor 15c to feed the grindstone head 16 forward. Then, in S132, the control unit 65 determines whether or not the tip detection unit 41 of the touch probe 40 and the eccentric portion Wa of the work W have come into contact with each other. The grindstone base 16 is moved forward until it comes into contact (S132: No).

  Then, in the case of contact (S132: Yes), as shown in FIG. 23, the control unit 65 stops the X-axis feed motor 15c and stores the rotation angle θ1 from the output of the spindle encoder 12c in S133. Further, in S134, the probe position, that is, the center distance x2 between the rotation axis Wc and the tip detection unit 41 of the touch probe 40 is stored.

  Subsequently, in S135, the control unit 65 causes the grindstone base 16 to retreat and moves the touch probe 40 to the retracted posture (see FIG. 14 of the first embodiment). With that, the process ends. Note that S123 to S124 and S130 to S131 correspond to a plurality of relative movement steps in the present invention, and S125 and S132 correspond to a plurality of detection steps.

(2-2. Description of calculation process)
Next, the calculation step of S5 in the present embodiment will be described in detail with reference to FIGS. 16 and 24. FIG. 24 is a schematic view of the measuring device and the touch probe in which the calculation process is performed, viewed from the axial direction. In FIG. 24, the actual position of the eccentric portion Wa is shown by a solid line, and the set position (position under ideal conditions) is shown by a broken line.

  Similar to the first embodiment, the pin diameter that is the radius of the eccentric portion Wa is r1, the half stroke that is half the stroke of the eccentric portion center Wac that rotates around the work axis Wc is r2, and the spherical tip. Let R be the probe radius that is the radius of the detection unit 41. When the phase of the eccentric center Wac at the upper contact position with respect to the reference line is θ7 and the measurement deviation angle due to the pin diameter variation is θ5, the following [Equation 2-8] to [Equation 2-10] hold. a1, b1, c1 are values at the upper contact positions corresponding to a, b, c shown in FIG.

a1 = R + r1 [Equation 8]
b1 = x1− (r2 * cos θ7) [Equation 2-9]
c1 = (r2 * sin θ7) −y1 [Equation 2-10]
a1 ² = b1 ² + c1 ² [Equation 2-11]

Further, when the phase of the eccentric center Wac at the lower contact position with respect to the reference line is θ8, the following [Equation 2-12] to [Equation 2-14] are established. a2, b2, c2 are values at the lower contact positions corresponding to a, b, c shown in FIG.
a2 = R + r1 [Equation 2-12]
b2 = x2- (r2 * cos θ8) ... [Equation 2-13]
c2 = (r2 * cos θ8) −y2 [Equation 2-14]
a2 ² = b2 ² + c2 ² ... [Equation 2-15]

Since b1 ² + c1 ² = b2 ² + c2 ² is established from a1 = a2, θ7 and θ8 are obtained, and the pin diameter r1 can be obtained by substituting it in [Equation 2-11]. Further, the measurement deviation angle θ5 due to the pin diameter variation is obtained by the following [Equation 2-16].
θ5 = (θ1−θ7−θ8) / 2 ... [Equation 2-16]
Further, the mounting deviation angle θ6 of the work W with respect to the spindle 12a is obtained by the following [Formula 2-17].
θ6 = (θ1−θ3 + θ5 + θ8) −90 ... [Equation 2-17]

(2-3. Summary)
As described above, also by the phase indexing method of the present embodiment, the pin diameter r1 can be efficiently obtained as the measurement result of the outer diameter of the eccentric portion Wa without separately performing the operation for measuring the outer diameter. In addition to the above, it is possible to shorten the entire time from the phase indexing to the completion of the grinding process by setting the roughing start diameter xs1 using the pin diameter r1 and performing the grinding process. Has the same effect.

<Modification>
The present invention is not limited to the above-described embodiments, and various changes can be made without departing from the gist of the present invention. In the above embodiment, an example in which the present invention is applied to a grinder that grinds a crank pin of a crankshaft has been shown, but the present invention is not limited to this. For example, it can be applied to a cam grinder that grinds a cam shaft. In short, the present invention can be applied to a grinder that grinds a work having an eccentric portion that is eccentric from the rotation axis.

W ... Work, Wc ... Rotating shaft center, Wa ... Eccentric part (processed part), 1 ... Grinding machine, 12a ... Spindle, 16 ... Grinding wheel stand, 17 ... Grinding wheel, 40 ... Touch probe, 41 ... Tip detection part, 65 ... Control part, S2-S3 ... Attachment process, S23-S24, S30-S31, S123-S124, S130-S131 ... Relative movement process, S25, S32, S125, S132 ... Detection process, S61 ... Roughing start diameter setting Step (grinding start diameter setting step), S62 ... Phase correction step, S63 ... Fast forward step, S65 ... Rough grinding step (grinding step).

Claims (6)

While rotating a work having a work piece that is eccentric with respect to the rotation axis by a spindle, a grinding wheel supported by a grinding wheel head that relatively feeds in a first axial direction intersecting the rotation axis is brought into contact with the workpiece. A method for indexing the phase of the work in a grinding machine for grinding a work part,
An attaching step of attaching the work to the spindle,
A plurality of relative movements in which one of the tip detection portion of the touch probe attached to the whetstone and the processed portion of the workpiece attached to the main spindle is made to stand by at a plurality of locations and the other is approached to the one Process,
During each of the relative movement steps, a plurality of detection steps for respectively detecting that the tip detection section has contacted the processed section,
The phase of the work is indexed using the rotation angle of the spindle and the position of the tip detection unit at the time of contact detection at the plurality of locations, and the calculation is performed based on the geometrical relationship between the processed portion and the tip detection unit. And a step of calculating the outer diameter of the processed portion by the method.   In the calculation step, in a state where the tip detection unit and the processed portion are in contact with each other, a first straight line passing through the center of the tip detection unit and parallel to the first axial direction and a center of the processed portion are passed. And a second straight line parallel to the second axial direction that intersects the first axial direction and the rotation axis, and a third straight line that passes through the center of the processed portion and the center of the tip detection portion. The phase indexing method according to claim 1, wherein the outer diameter of the processed portion is obtained based on the geometrical relationship of the triangles.   In the plurality of relative movement steps, the grindstone base is stopped after a relative feed operation, the tip detection unit of the touch probe is made to stand by at a plurality of positions, and the main spindle is rotated to move the workpiece portion of the workpiece. The phase indexing method according to claim 1 or 2, wherein the phase indexing method is brought closer to the tip detection unit.   In the plurality of relative movement steps, the spindle is stopped after rotating, the work piece of the workpiece is made to stand by at a plurality of locations, and the grindstone base is fed to operate so that the tip detecting portion of the touch probe is the tip. The phase indexing method according to claim 1 or 2, wherein the phase indexing method is brought close to each of the detection units. After performing the phase indexing method according to any one of claims 1 to 4, a fast-forwarding step of fast-forwarding the grindstone toward the workpiece, and a speed slower than the fast-forwarding step after the fast-forwarding step. A grinding method for carrying out at least one grinding step for grinding the processed part while feeding a grindstone,
A grinding method comprising a grinding start diameter setting step of setting a feed position of the grinding wheel head at the start of the grinding step as a grinding start diameter using the outer diameter of the processed portion obtained in the calculation step.   The grinding method according to claim 5, further comprising a phase correction step of correcting the phase by rotating the main shaft by an amount of a shift angle obtained based on the phase of the workpiece indexed in the calculation step.

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