JP2006162549A - Positioning tool and positioning method for work - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positioning tool and a positioning method for a work capable of enhancing measuring precision by simplifying structure. <P>SOLUTION: An inner clamper 61 is attached to an upper end part W1 of the work W set by engaging six vertical ball grooves 10 on an inner circumferential face respectively with six phase guides 7 arranged on a measuring block. A pin 64 is slid circumferentially because an inclined part 62 of a clamper 11 goes down while abutting to the pin 64 of the inner clamper 61, when the clamper 11 is inserted into the inner clamper 61, and the inner clamper 61 and the work W are rotated. The work W is not fluctuated circumferentially during measurement to enhance the measuring precision, because one end of each of the vertical ball grooves 10 contacts with the corresponding phase guide 7 to fix the work W positionedly along a circumferential direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a workpiece positioning tool and a positioning method for positioning a outer race in the circumferential direction in order to measure dimensions of an outer race that is used in a constant velocity joint and has a plurality of vertical ball grooves on an inner circumferential surface. It is.

  In general, when measuring various dimensions of an outer race (hereinafter referred to as a workpiece) having a plurality of vertical ball grooves formed at equal angular intervals in the circumferential direction of the inner circumferential surface, the workpiece is placed in the circumferential direction on the measuring machine. In addition, positioning and fixing in the radial direction are performed, and a measuring ball at the tip of the probe is brought into contact with each of the vertical ball grooves. Then, the workpiece is slid by a predetermined distance in the axial direction, and the radial position of each vertical ball groove is measured by each sensor at multiple points in the vertical direction, and the dimensions of the workpiece are measured by a measurement program based on the measurement result, For example, the center of the workpiece, the distance from the center to the vertical ball groove, the distance between the opposing vertical ball grooves, and the like are calculated.

Therefore, a conventional measurement method for measuring various dimensions of a work having a plurality of vertical ball grooves on the inner peripheral surface will be briefly described with reference to FIGS.
As shown in FIG. 5 and FIG. 6, a plurality of phase guides 7 arranged at equiangular intervals on the circumference are fitted into the plurality of vertical ball grooves 10 formed on the inner peripheral surface of the workpiece W, respectively. In addition to positioning in the circumferential direction, the convex portion 44 at the upper end of the radial guide rod 40 extending in the vertical direction is fitted into the concave portion 43 in the center of the upper wall surface in the workpiece W to perform positioning in the radial direction. Set on stand 5.
Next, as shown in FIGS. 1 and 2, the air cylinder 17 with a lock is driven and the clamper 11 is lowered, and the clamper 11 is inserted into the shaft portion W1 at the upper end portion of the work W, and the end surface W2 at the base of the shaft. To fix. At this time, each measuring element 46 is constantly urged toward each vertical ball groove 10 by a tension spring 57 so that the measuring ball 50 at the tip of each measuring element 46 can always press each vertical ball groove 10.

  Then, the workpiece W thus positioned and fixed is moved a predetermined distance in the vertical direction at a predetermined speed in a state where the measuring ball 50 at the tip of each measuring element 46 is in contact with each vertical ball groove 10. Then, the position of each vertical ball groove 10 in the radial direction is measured by the sensor 54 at multiple points in the vertical direction of each vertical ball groove 10. Based on the measured values, various dimensions of the workpiece W, for example, the center of the workpiece W, the distance from the center to the vertical ball groove 10, the distance between the opposing vertical ball grooves 10, 10 and the like are calculated by the measurement program. The

However, in the conventional measuring machine, the width X of the phase guide 7 is set to the minimum dimension in the manufacturing dimension tolerance of the opening width Y of the vertical ball groove 10 provided in the workpiece W. Therefore, as shown in FIG. Since the opening width Y of the vertical ball groove 10 is larger than the width X of the phase guide 7, a gap Z is generated between the phase guide 7 and the vertical ball groove 10, and the workpiece W cannot be positioned in the circumferential direction. During the measurement by the above method, the workpiece W was swung in the circumferential direction by the gap Z, and the measurement accuracy was deteriorated.
In addition, when the workpiece (master) that has been subjected to the same measurement with another measuring machine is measured by the above-described method, the above-described backlash occurs, and the positions where the master and all the workpieces to be measured are positioned are different. For this reason, the measurement conditions do not match, the measured values vary, and the workpiece cannot be measured with high accuracy.

Therefore, as a circumferential positioning means for the workpiece measuring machine described above, Patent Document 1 discloses a measuring device that automatically measures the dimension between the ball grooves of the outer race used in the constant velocity ball joint. That is, in Patent Document 1, first, the workpiece is clamped on the rotation shaft, the rotation shaft is rotated by the indexing motor, the workpiece is rotated, and the angle at which the ball groove is detected by the ball groove sensor. The workpiece is positioned at the position. Thereafter, the work is slid in the axial direction, and a pair of measurement balls are inserted into the work, and these measurement balls are engaged with each of two opposing ball grooves. At this time, the workpiece is further finely rotated by the indexing motor, and the workpiece is positioned and fixed at the angular position where the output of the electric micrometer reaches the maximum value, that is, the angular position where the measurement ball accurately matches the ball groove. Is disclosed.
JP-A-62-214312

  In the invention of Patent Document 1 described above, the workpiece is split so that the pair of measuring balls accurately engages with the opposing ball grooves, that is, the opposing ball grooves are arranged on the operation straight line of the pair of measuring balls. Positioning in the circumferential direction is performed by rotating in two stages by the take-out motor, but the mechanism for positioning is complicated and expensive, and there is a risk that the time for positioning the workpiece will be longer. Work efficiency when measuring.

  This invention is made | formed in view of this point, and it aims at providing the positioning tool and the positioning method of the workpiece | work which simplify a structure and improve a measurement precision.

As a means for solving the above-mentioned problems, the present invention provides a workpiece positioning tool according to claim 1, wherein a workpiece having a plurality of vertical ball grooves as measurement points on an inner peripheral surface is provided to a measuring machine. In the workpiece positioning tool for positioning in the circumferential direction, a plurality of phase guides fitted into each of the plurality of vertical ball grooves and arranged at equal angular intervals on the circumference, and the end of the workpiece A clamper that is inserted into a portion and fixes the workpiece, and when the clamper is inserted and fixed to an end portion of the workpiece, the workpiece is rotated in the circumferential direction so that one end of each vertical ball groove corresponds to the corresponding And rotating means for contacting one end of the phase guide.
The invention of the workpiece positioning tool described in claim 2 is the invention described in claim 1, wherein the rotating means is interposed between the clamper and the workpiece and attached to an end of the workpiece. An inner clamper, a pin projecting from a predetermined portion of the inner clamper, and an inclined portion provided on the clamper and capable of contacting the pin, and inserting the clamper into an end of the inner clamper, The pin is slid along the inclined portion while the inclined portion of the clamper is in contact with the end portion of the pin of the inner clamper, and the workpiece is rotated in the circumferential direction together with the inner clamper. It is what.

In the invention of the workpiece positioning method according to claim 3, when a workpiece having a plurality of vertical ball grooves, which are measurement locations, is positioned on the inner peripheral surface and fixed in the circumferential direction with respect to the measuring machine, First, a plurality of phase guides arranged at equal angular intervals on the circumference are fitted and set in the plurality of vertical ball grooves of the workpiece, respectively, and then a clamper is attached to the end portion of the workpiece. When the workpiece is inserted and fixed, the workpiece is rotated in the circumferential direction, and one end of each of the vertical ball grooves is positioned and fixed in a state of being in contact with one end of the corresponding phase guide. Is.
A work positioning method according to a fourth aspect of the present invention is the work positioning method according to the third aspect, wherein a plurality of phases are arranged at equal angular intervals on the circumference in the plurality of vertical ball grooves of the work. The step of fitting and setting each guide includes a plurality of measuring balls extending from the measuring machine and being bent in the circumferential direction of the workpiece, with the measuring balls at the tips of the vertical ball grooves of the workpiece. It is characterized by including the process made to contact.

Therefore, in the workpiece positioning tool according to the first aspect of the invention, when the clamper is inserted into the end portion of the workpiece to fix the workpiece, the workpiece is rotated in the circumferential direction, and one end of each vertical ball groove of the workpiece is Are positioned and fixed in contact with one end of the corresponding phase guide.
In the workpiece positioning tool according to claim 2, when the clamper is inserted into the end portion of the inner clamper, the inclined portion of the clamper abuts on the end portion of the pin of the inner clamper, and the pin extends along the inclined portion. Since it slides, the work is rotated in the circumferential direction together with the inner clamper.

In the work positioning method according to the third aspect of the invention, first, the phase guide is fitted and set in each vertical ball groove of the work, and then the clamper is inserted and fixed to the end of the work. When the workpiece is rotated in the circumferential direction, the workpiece is positioned and fixed in a state where one end of each vertical ball groove is in contact with one end of the corresponding phase guide.
In the invention of the workpiece positioning method according to claim 4, when the clamper is inserted into the end portion of the workpiece and fixed, the workpiece is rotated in the circumferential direction, and the workpiece corresponds to one end of each vertical ball groove. When the probe is positioned and fixed in contact with one end of the workpiece, each measuring element bends in the circumferential direction of the workpiece as the workpiece rotates, and each measuring ball at the tip comes into contact with each vertical ball groove. State is maintained.

  ADVANTAGE OF THE INVENTION According to this invention, the structure can be simplified and the workpiece positioning tool and its positioning method which improve a measurement precision can be provided.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to FIGS.
The workpiece positioning tool according to the embodiment of the present invention is employed in the measuring machine shown in FIGS. 1 to 4. First, the main configuration of the measuring machine will be described in detail.
As shown in FIGS. 1 to 4, the measuring machine includes first to third frames 1 to 3 framed by a plurality of frames and plates, and includes a first frame 1 and a second frame 2. Are arranged side by side, and the third frame 3 is disposed below the first frame 1.
As shown in FIGS. 1 and 2, the measurement table 5 on which the workpiece W is placed is fixed on a lower plate 1 a having an opening 1 b of the first frame 1. The measuring table 5 is formed in a block shape in which a plurality of plate materials are combined, and has an opening 6 penetrating vertically at the approximate center thereof, and is shown between the upper surface of the measuring table 5 and the lower frame 1a. The elastic member which does not carry out is incorporated, and the upper surface of the measuring table 5 is configured to move up and down relative to the lower frame 1a.

  As shown in FIGS. 1 and 2, a phase guide 7 is erected on the periphery of the upper end of the opening 6 of the measurement table 5. As shown in FIG. 6, the number of phase guides 7 corresponds to the number of the vertical ball grooves 10 of the workpiece W (six in this embodiment) with an equiangular interval around the upper edge of the circular opening 6. ) Is arranged. The phase guide 7 will be described later in detail.

  A cylindrical clamper 11 is fixed to the moving table 12 above the measuring table 5 as shown in FIGS. The moving table 12 is connected to the upper plate 14 via a connecting plate 13 that extends vertically. Cylindrical guides 15 and 15 are fixed to the movable table 12 and the upper plate 14, respectively. These cylindrical guides 15 and 15 are inserted into a guide bar 16 fixed to the first frame 1, and the upper cylindrical guide 15 is arranged in parallel with the measuring table 5 and fixed to the first frame 1. It is connected to the cylinder rod 18 of the air cylinder 17 with lock. The air cylinder 17 with a lock has a function of extending and retracting the cylinder rod 18 to lock the cylinder rod 18 at an appropriate position.

  Further, as shown in FIGS. 1 and 2, an air cylinder 19 with a lock is disposed above the clamper 11 and is fixed to the upper plate 14. The air cylinder 19 with a lock has a function of extending and retracting the cylinder rod 20 and locking the cylinder rod 20 at the maximum extension position. An intermediate plate 21 is fixed to the lower end of the cylinder rod 20 of the air cylinder 19 with a lock. Rods 22 and 22 are fixed to both sides of the intermediate plate 21, respectively. These rods 22 and 22 can move up and down in the movable table 12, and projecting portions 24 and 24 are provided at the lower ends thereof via a lower plate 23, respectively.

When the air cylinder 17 with the lock is driven, the cylinder rod 18 is retracted, and the clamper 11 is moved to the inner clamper 61 while the air cylinder 19 with the lock, the moving base 12 and the clamper 11 are lowered to the position indicated by the one-dot chain line. The cylinder rod 18 is locked by being inserted into a cylindrical shaft portion W1 extending above the workpiece W via (see FIG. 5) and fixing the end surface W2 at the base of the workpiece W. Then, the workpiece W is fixed by the clamper 11.
Next, when the air cylinder 19 with a lock is driven, the cylinder rod 20 is extended, and the two rods 22 and 22 fixed to the upper plate 21 are moved down in the movable table 12 so that the protrusions at the lower ends are respectively provided. The parts 24 and 24 are locked by pressing the upper surface of the measuring table 5. At this time, the upper surface of the measuring table 5 is pressed by the protrusions 24 and 24 and lowered by a predetermined distance, and the upper end of the phase guide 7 is lowered to the vicinity of the lower end of the workpiece W. With this configuration, the vertical measurement range of the vertical ball groove 10 of the workpiece W can be expanded.

  Further, as shown in FIG. 3, the first frame 1 is supported by the second frame 2 so as to be movable up and down. That is, a cylindrical moving body 32 having a threaded portion on the inner surface is connected to the frame 30 of the first frame 1 via a cylindrical guide 31. The cylindrical moving body 32 is attached to a rod-like rotating body 33 that extends from the servomotor 34 and has a threaded portion on the outer peripheral surface. The rod-shaped rotating body 33 is supported by the frame 2a of the second frame 2 so as to be rotatable. When the rod-shaped rotating body 33 is rotated by the servo motor 34, the first frame body 1 moves in the vertical direction together with the cylindrical moving body 32. Therefore, guide bodies 36, 36 inserted through guide rods 35 extending above and below the second frame 2 are respectively arranged above and below the cylindrical moving body 32, and are arranged on the frame 30 of the first frame 1. It is fixed.

  Furthermore, as shown in FIG. 4, the third frame 3 is disposed below the measurement table 5 provided in the first frame 1, and below the lower frame 3 a of the third frame 3. Is provided with a sensor (not shown) for measuring the movement distance of the workpiece W in the vertical direction. The shaft 41 extending from the sensor is in contact with the lower end of a radial guide rod 40 that passes through the shaft guide block 42 and positions the workpiece W in the radial direction. The lower end of the radial guide rod 40 is fixed to a fixing portion 5a provided at the center of the cylindrical plate 5b. The cylindrical plate 5b is fixed to the bottom surface of the measuring table 5 and is disposed in the opening 1b of the lower plate 1a. The radial guide rod 40 extends to the center of the opening 6 of the measuring table 5, and a trapezoidal convex portion 44 formed at the upper end of the radial guide rod 40 is engaged with a concave portion 43 provided on the central upper wall surface in the workpiece W. Come together. Further, a compression spring 45 that constantly urges the radial guide rod 40 upward is disposed along the outer peripheral surface of the shaft 41 between the shaft guide block 42 and the fixed portion 5a of the cylindrical plate 5b. ing.

  As shown in FIG. 4, around the radial guide rod 40, a number (six in this embodiment) of measuring elements 46 corresponding to the number of vertical ball grooves 10 (see FIG. 6) of the workpiece W are circular. They are arranged at equiangular intervals on the circumference. These measuring elements 46 are composed of an upper measuring element 47 disposed on the upper part and a lower measuring element 49 connected to the upper measuring element 47 via a leaf spring 48.

  As shown in FIG. 4, the upper measuring element 47 has a plate-like lower part and a bar-like part from the middle part to the upper part. A measuring ball 50 is formed on the upper end of the upper probe 47 so as to face outward. The diameter of the measuring ball 50 is set to be approximately equal to the diameter of the vertical ball groove 10 (see FIG. 6) of the workpiece W. The measuring element 46 can be bent in the circumferential direction at a portion of the leaf spring 48, and the measuring ball 50 at the tip can swing in the direction of the arrow.

  As shown in FIG. 4, the lower probe 49 is composed of an upper block-like probe 51 and a lower block-like probe 52, and is connected by vertical block-like probe 53, 53 ′ extending vertically. . A sensor main body 54 is arranged on the end face of the upper block-shaped probe 51 so that the sensor portion 54 ′ can come into contact with the sensor block 54, and the sensor main body 54 is fixed to the lower frame 3 a of the third frame 3. The upper part of the character block 56 is fixed. The position of the measuring ball 50 at the tip of the measuring element 46 (the position in the radial direction of the vertical ball groove 10) can be detected by the sensor unit 54 '.

  Further, as shown in FIG. 4, a tension spring 57 is disposed below the sensor portion 54 ′, one end of which is connected to the vertical block-shaped measuring element 53 ′, and the other end is an intermediate portion of the L-shaped block 56. It is connected to the. The measuring ball 50 at the tip of each measuring element 46 is always configured to urge the vertical ball groove 10 (see FIG. 6) of the workpiece W by the tension spring 57.

Further, an air cylinder 55 is disposed below the tension spring 57 and is fixed to an intermediate portion of the L-shaped block 56. When the measurement of the workpiece W is completed, the air cylinder 55 is driven, the tip of the cylinder rod 55 ′ pushes the end surface of the vertical block-shaped measuring element 53, and the measuring ball 50 at the leading end of the measuring element 46 is removed from the vertical ball groove 10. It is comprised so that it may space apart.
Note that the above-described configuration is a configuration for one measuring element 46, and the same configuration is adopted for the remaining five measuring elements 46.

  The workpiece positioning tool according to the embodiment of the present invention is fitted into each of the six vertical ball grooves 10 on the inner peripheral surface of the workpiece W, as shown in FIGS. 6 phase guides 7 arranged at equiangular intervals, and a clamper that is slidable in the vertical direction and is inserted into the shaft portion W1 of the upper end portion of the workpiece W to fix the end surface W2 at the axis of the workpiece W 11 and when the clamper 11 is lowered and inserted into the shaft portion W1 of the upper end portion of the workpiece W to be fixed, the workpiece W is rotated in the circumferential direction so that one end of each vertical ball groove 10 corresponds to the corresponding phase guide 7. Rotating means 60 that is brought into contact with one end of the vertical portion 8.

  As described above, six phase guides 7 are arranged at equiangular intervals on the upper edge of the opening 6 of the measurement table 5. As shown in FIGS. 1 and 6, these phase guides 7 are formed in a substantially L shape in a side view, and the vertical portion 8 has six vertical portions formed on the inner peripheral surface of the workpiece W. The ball grooves 10 are respectively fitted. The vertical portion 8 is formed in a substantially rectangular shape when viewed from above. Since the longitudinal width X of the vertical portion 8 is shorter than the opening width Y of the vertical ball groove 10, when each of the vertical ball grooves 10 of the workpiece W is fitted to the vertical portion 8 of each phase guide 7, A gap Z is formed between both ends of each vertical portion 8 and both edges of the opening of each vertical ball groove 10.

  As shown in FIGS. 5 and 6, the rotating means 60 is interposed between the clamper 11 and the shaft portion W1 at the upper end portion of the work W, and an inner clamper 61 mounted on the shaft portion W1 of the work W. The inner clamper 61 includes a pin 64 projecting upward from the annular flange 63 at the lower end of the inner clamper 61, and an inclined portion 62 provided on the annular lower end surface 65 of the clamper 11 to which the pin 64 can abut. The inclined portion 62 is inclined obliquely upward from the annular lower end surface 65 in the counterclockwise direction.

When the rotating means 60 is configured in this way, the outer periphery of the shaft portion W1 of the workpiece W set by fitting each vertical ball groove 10 on the inner peripheral surface to each of the phase guides 7 on the measuring table 5 is provided. It is mounted so that the inner peripheral surface of the inner clamper 61 is brought into contact with the surface. Thereafter, the clamper 11 is lowered and inserted into the end portion of the inner clamper 61. Then, the inclined portion 62 of the clamper 11 descends while contacting the upper end of the pin 64 of the inner clamper 61, the pin 64 slides in the circumferential direction along the inclined portion 62, and the workpiece W together with the inner clamper 61 in the circumferential direction. Rotates counterclockwise. Then, as shown in FIG. 7, one end of each vertical ball groove 10 comes into contact with one end of the vertical portion 8 of the corresponding phase guide 7, and the workpiece W can be positioned in the circumferential direction.
In FIG. 5, only one set of the pin 64 and the inclined portion 62 corresponding to the pin 64 is formed, but an appropriate number may be formed.

Next, a method for positioning the workpiece W on the above-described measuring machine will be described.
First, the workpiece W is fitted to each of the six phase guides 7 arranged at equal angular intervals on the circumference of each of the six vertical ball grooves 10 on the inner peripheral surface thereof. And the convex part 44 provided in the upper end of the radial direction guide rod 40 is fitted to the recessed part 43 of the center upper wall part in the workpiece | work W, and it sets to the measurement stand 5. FIG. At this time, the cylinder rod 55 ′ of the air cylinder 55 is not extended, and the measuring balls 50 at the tips of the six measuring elements 46 urge the corresponding vertical ball grooves 10 by the tension springs 57. It has a form. Further, at this stage, a gap Z is formed between the vertical portion 8 of the phase guide 7 and the vertical ball groove 10, and the workpiece W is not firmly positioned in the circumferential direction.

Next, after the inner clamper 61 is mounted in contact with the shaft portion W1 of the workpiece W, the air cylinder 17 with the lock is driven, and the air cylinder 19 with the lock, the movable table 12, and the clamper 11 are indicated by a one-dot chain line. The clamper 11 is lowered to the position, and the clamper 11 is inserted into the end of the inner clamper 61.
Then, the inclined portion 62 of the clamper 11 descends while contacting the upper end of the pin 64 of the inner clamper 61, the pin 64 slides in the circumferential direction along the inclined portion 62, and the workpiece W is moved in the circumferential direction together with the inner clamper 61. Rotates counterclockwise.
Then, as shown in FIG. 7, one end of each vertical ball groove 10 comes into contact with one end of the vertical portion 8 of the corresponding phase guide 7, and the workpiece W is positioned and fixed.
At the same time, the measuring balls 50 at the tips of the six measuring elements 46 are bent in the rotational direction (counterclockwise direction) of the workpiece W simultaneously with the rotation of the workpiece W, so that each vertical ball Contact with the groove 10 is maintained.

Next, the air cylinder 19 with a lock is driven, and the upper surface of the measuring table 5 is pressed by the two rods 22 and 22 to be lowered by a predetermined distance, and the upper end of the vertical portion 8 of the phase guide 7 is the workpiece W. It becomes the form which descended to the lower end vicinity.
Thus, the positioning of the workpiece W is completed.

Another method in the positioning method described above will be described.
In the positioning method described above, before the workpiece W is rotated, each measuring ball 50 is previously brought into contact with the vertical ball groove 10, and the workpiece W is rotated in this state to complete the positioning. Until all the positioning is completed, the cylinder rod 55 ′ of the air cylinder 55 is extended to keep each measuring ball 50 retracted from the vertical ball groove 10. Then, after the rotation of the workpiece W is completed and all positioning is completed, the cylinder rod 55 ′ of the air cylinder 55 is retracted, and each measuring ball 50 is brought into contact with the inner peripheral surface of the workpiece W by the tension spring 57. At the same time, the leaf spring 48 is bent in the rotation direction of the workpiece W so that each measurement ball 50 is brought into contact with the corresponding vertical ball groove 10. By adopting this method, each measuring element 46 is prevented from being deformed or damaged by a load acting on the workpiece W during positioning of the workpiece W.

  Then, the workpiece W is moved at a predetermined speed in the vertical direction by driving the motor 34, and the radial positions of all the vertical ball grooves 10 are simultaneously measured by the sensors 54 at multiple points in the vertical direction. . Based on the measurement results, the measurement program calculates various dimensions of the workpiece W, for example, the center of the workpiece W, the distance from the center to the vertical ball groove 10, and the distance between the opposing vertical ball grooves 10, 10. The

  Thereafter, when the measurement of the workpiece W is completed, each air cylinder 55 is driven so that the measuring ball 50 at the tip of each measuring element 46 is separated from each vertical ball groove 10 and the clamper 11 is moved back by the air cylinder 17 with a lock. In the state of being raised to the position, the workpiece W after measurement is removed, the next workpiece W is fitted to the phase guide 7, and the above-described operation is repeated.

  As described above, according to the embodiment of the present invention, the six phase guides 7 arranged on the measurement table 5 are set by fitting the six vertical ball grooves 10 on the inner peripheral surface. The inner clamper 61 is mounted on the shaft portion W1 of the workpiece W. Thereafter, when the clamper 11 is inserted into the inner clamper 61, the inclined portion 62 of the clamper 11 descends while contacting the pin 64 of the inner clamper 61, the pin 64 slides in the circumferential direction, and the workpiece W together with the inner clamper 61 is moved. Rotates. Then, one end of each vertical ball groove 10 comes into contact with one end of the corresponding vertical portion 8 of the phase guide 7, and the workpiece W is positioned and fixed in the circumferential direction.

Thereby, even if the workpiece W is moved in the vertical direction by driving the motor 34, the workpiece W is firmly positioned and fixed, so that the workpiece W does not swing in the circumferential direction during measurement, and the measurement accuracy is improved. Can be improved. Moreover, even when measuring the master of the workpiece W, since the master is rotated and positioned and measured as described above, the positioning position of the master and the workpiece W to be measured is approximated and the measurement conditions are approximated. Since they match, the measurement result of the workpiece W can be compared with the master, and the workpiece W can be measured with high accuracy.
Furthermore, since the workpiece positioning tool according to the embodiment of the present invention does not employ a complicated structure and control and simplifies the structure, it is possible to provide an inexpensive workpiece positioning tool.

FIG. 1 is a diagram showing an upper part of the front of a measuring machine employing a workpiece positioning tool according to an embodiment of the present invention. FIG. 2 is a diagram showing a part of the side surface of the measuring machine of FIG. FIG. 3 is a view showing a part of the side surface of the measuring machine of FIG. FIG. 4A shows the lower part of the front face of the measuring instrument of FIG. 1, and FIG. 4B is an enlarged view of the measuring element. FIG. 5 is an enlarged view of the workpiece positioning tool according to the embodiment of the present invention. FIG. 6 is a top view in which the vertical ball groove of the work is fitted to the phase guide. FIG. 7 is a top view showing a state in which the work is rotated and one end of the vertical ball groove is in contact with one end of the phase guide.

Explanation of symbols

7 phase guide, 10 vertical ball groove, 11 clamper, 46 probe, 50 measurement ball,
60 Rotating means, 61 Inner clamper, 62 Inclined part, 64 pins, W work, W1 Shaft part (end part)

Claims (4)

In a workpiece positioning tool for positioning a workpiece having a plurality of vertical ball grooves, which are measurement points, on the inner peripheral surface thereof in the circumferential direction with respect to a measuring machine,
A plurality of phase guides fitted into each of the plurality of vertical ball grooves and arranged at equal angular intervals on the circumference; a clamper inserted into an end of the workpiece to fix the workpiece; Rotating means for rotating the workpiece in the circumferential direction and bringing one end of each vertical ball groove into contact with one end of the corresponding phase guide when the clamper is inserted and fixed to the end of the workpiece. A workpiece positioning tool characterized by that. The rotating means is provided between the clamper and the workpiece, provided on the clamper, an inner clamper mounted on an end of the workpiece, a pin protruding from a predetermined portion of the inner clamper, When the clamper is inserted into an end portion of the inner clamper, the inclined portion of the clamper is in contact with an end portion of the pin of the inner clamper, and the pin is 2. The workpiece positioning tool according to claim 1, wherein the workpiece is slid along an inclined portion and the workpiece rotates in the circumferential direction together with the inner clamper. When fixing a workpiece having a plurality of vertical ball grooves that are measurement locations on the inner peripheral surface by positioning in the circumferential direction with respect to the measuring machine, first, in the plurality of vertical ball grooves of the workpiece, A plurality of phase guides arranged at equiangular intervals on the circumference are respectively fitted and set, and then the workpiece is moved in the circumferential direction when the clamper is inserted and fixed to the end of the workpiece. And positioning and fixing in a state where one end of each vertical ball groove is in contact with one end of the corresponding phase guide. The step of fitting and setting a plurality of phase guides arranged at equal angular intervals on the circumference of the plurality of vertical ball grooves of the workpiece respectively extends a plurality of phases from the measuring machine. 4. The work positioning method according to claim 3, further comprising a step of bringing a measuring ball at the tip of each measuring element, which can be bent in a direction, into contact with each of the vertical ball grooves of the work.

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