JP7360699B2 - Test object fixing device for dynamic balance test machine and dynamic balance test machine - Google Patents

Description

The present invention relates to a test object fixing device for a dynamic balance tester, and a dynamic balance tester including this test object fixing device.

A dynamic balance tester measures the unbalance of a test object by rotating a rotating part such as a spindle to which the test object is fixed at a predetermined speed. The dynamic balance tester includes a test object fixing device that fixes the test object to a rotating part. For example, a test object fixing device for a test object that has a flange-shaped outer peripheral part and a center hole generally has a shaft that is inserted into the center hole with a clearance fit, and a clamp part that clamps the outer peripheral part. It is. Such a test object fixing device essentially fixes the test object to the rotating part simply by clamping the outer circumference of the test object.

If the test object fixing device fixes the test object to the rotating part by simply clamping the outer periphery of the test object, there may be a mounting error (so-called misalignment) of the test object with respect to the test object fixing device or the rotating part. Since this tends to occur, it is difficult to improve the accuracy of unbalance measurement. Particularly, during unbalance measurement in a dynamic balance tester, the rotating part rotates at a relatively high speed, so mounting errors of the test object have a large effect on the unbalance measurement accuracy.

The present invention provides a test object fixing device for a dynamic balance tester that can improve unbalance measurement accuracy by suppressing mounting errors of the test object, and a dynamic balance tester including this test object fixing device. The purpose is to provide.

One embodiment of the present invention provides a fixing part (2E) to which an outer peripheral part (2E) remote from the reference hole is fixed in a test object (2) which is rotatable and has a reference hole (2C) formed at the center of rotation. 45), a cylindrical gripping part (42) that is inserted into the reference hole and grips the inner peripheral part (2B) of the test object in the reference hole, and a plurality of grooves (32A) are arranged in the gripping part (42); a collet (32) that is formed in parallel in the circumferential direction (S) of the part and has a gripping part that can be expanded and contracted according to a change in the groove width (W) of the dividing groove; and an expansion/contraction mechanism (46) that expands and contracts the gripping part. ) A test object fixing device (4) for a dynamic balance test machine is provided . Further, an embodiment of the present invention provides a dynamic balance testing machine (1) including the test object fixing device and a rotating part (3) to which the test object fixing device is attached and rotates in the circumferential direction. Provide . Note that alphanumeric characters in parentheses represent corresponding components in the embodiments described later.

According to this configuration, in the test object fixing device, the outer peripheral part of the test object away from the reference hole located at the center of rotation is fixed to the fixing part, and the cylindrical grip part of the collet is fixed to the reference hole. By expanding the diameter in the inserted state and press-fitting into the reference hole, the inner circumference of the test object in the reference hole is gripped. When fixing both the inner and outer circumferences of the test object in this way, the test object is likely to be placed concentrically with the test object fixing device and the rotating part. It is possible to improve the accuracy of unbalance measurement in a dynamic balance tester by suppressing attachment errors of the test object to the rotating part.
The test specimen fixing device may further include a main body. The collet may be fixed to an end surface of the main body. The fixing part is a support part formed on the end surface of the main body, and a claw part that can clamp the outer peripheral part by sandwiching it in a first direction along a first central axis of the collet. It may also include. The expansion/contraction mechanism has a drawbar that slides in the first direction, a metal tip that is slidable in the first direction along with the drawbar, and an outer circumferential surface that comes into contact with the gripping portion of the collet. A mandrel that slides in the first direction along with the metal fitting, the mandrel slides in one direction included in the first direction to expand the diameter of the gripping part of the collet, and the mandrel slides in the other direction included in the first direction. and a mandrel that slides in the other direction opposite to the one direction to reduce the diameter of the gripping portion of the collet. The test specimen fixing device is a shaft part to which the claw part is fixed, extends in the first direction, and is slidable in the first direction, and the shaft part is slidable in the one direction included in the first direction. a shaft portion that rotates in one rotational direction around a second central axis, and rotates in the opposite rotational direction around the second central axis as the shaft portion slides in the other direction included in the first direction; may further include. The test specimen fixing device further includes a connecting member that connects the shaft portion and the tip fitting so that the shaft portion slides in the first direction as the tip fitting slides in the first direction. May contain. As the tip fitting slides in the one direction, the shaft portion slides in the one direction, so that the claw portion faces the support portion in the other direction, and is spaced between the support portion and the support portion. The outer circumferential portion may be placed at a clamp position where the outer circumferential portion is clamped. When the shaft portion slides in the other direction as the tip fitting slides in the other direction, the claw portion is at a position rotated around the second central axis with respect to the clamp position. and may be arranged at a release position spaced apart from the clamp position in the other direction.

1 is a longitudinal sectional view of a main part of a dynamic balance testing machine according to an embodiment of the present invention. This is an enlarged view of the main part of FIG. 1. FIG. 2 is a view taken along arrow A in FIG. 1. FIG.

Embodiments of the invention will be described in detail below. FIG. 1 is a longitudinal cross-sectional view of a dynamic balance testing machine 1. The vertical direction in FIG. 1 is the vertical direction of the dynamic balance tester 1. The left-right direction in FIG. 1 is the left-right direction (first direction) of the dynamic balance tester 1. The dynamic balance testing machine 1 includes a rotating part 3 that rotates together with the test object 2, a support part (not shown) that supports the rotating part 3 in a vibrating and rotatable manner, and a motor etc. that rotationally drives the rotating part 3. A driving section (not shown), a detection section (not shown) that detects vibrations of the rotating section 3 during rotation, and a test object that supports the test object 2 and is connected to the rotating section 3 so as to be integrally rotatable. and a fixing device 4.

An example of the test object 2 is a long rotating body such as a propeller shaft, and one disk-shaped rubber coupling 2A is provided at each end of the body. The dynamic balance tester 1 includes two pairs of rotating parts 3 and test object fixing devices 4 so as to support both ends of the test object 2. In FIG. 1, only a pair of rotating parts 3 that support one end of the test object 2 in the longitudinal direction and a test object fixing device 4 are shown. Of course, if the test object 2 is not supported on both sides (cantilever supported), the dynamic balance tester 1 may include only one pair of the rotating section 3 and the test object fixing device 4.

A circular reference hole 2C bordered by an inner peripheral portion 2B is formed at the rotation center of the rubber coupling 2A. The reference hole 2C may be a through hole or a recessed portion having a bottom. The rubber coupling 2A has a resin cylindrical sleeve 2D that forms a part of the inner circumferential portion 2B, and a flange-shaped outer circumferential portion 2E that surrounds the inner circumferential portion 2B. The outer peripheral portion 2E has an annular shape that is radially outwardly away from the reference hole 2C of the rubber coupling 2A. One or more positioning holes 2F are formed in the outer peripheral part 2E, passing through the outer peripheral part 2E in the left-right direction.

The rotating part 3 includes a cylindrical spindle 11 having a center axis J (first center axis) extending in the left-right direction, and a cylindrical drawbar 12 coaxially disposed within the spindle 11. The spindle 11 and the drawbar 12 are, for example, spline-coupled at their root sides (left side), so the drawbar 12 is slidable relative to the spindle 11 in the left-right direction along the central axis J, and It can rotate integrally with the spindle 11 in the circumferential direction S around J. The dynamic balance tester 1 also includes an actuator (not shown) that slides the drawbar 12. The actuator is composed of an air cylinder or the like.

The spindle 11 has a plurality of parts, such as a cylindrical first part 13 forming its main body, and an annular second part 14 coaxially fixed to the right (tip side) end surface of the first part 13 by a bolt B1. It is made up of parts. The drawbar 12 may also be composed of multiple parts.

The test object fixing device 4 is attached to the rotating section 3 from the right side. The test object fixing device 4 includes a case 21 fixed to the spindle 11, a swivel shaft 22 supported by the case 21, a tip fitting 23 fixed to the drawbar 12 within the case 21, the swivel shaft 22 and the tip fitting. 23. The test object fixing device 4 includes a plurality of stage changing units 25 provided depending on the type of the test object 2.

The case 21 includes a cylindrical part 21A disposed coaxially with the spindle 11, a disc-shaped bottom part 21B coaxially fixed to the left end of the cylindrical part 21A, and a middle part of the cylindrical part 21A in the left-right direction. It has a disk-shaped partition portion 21C that divides the internal space of the cylindrical portion 21A into left and right halves. The cylindrical portion 21A, the bottom portion 21B, and the partition portion 21C may be integrally formed, or may be separate parts that are combined later.

Insertion holes 21D passing through the cylindrical portion 21A in the left-right direction are formed at a plurality of positions equally spaced apart in the circumferential direction S (in this embodiment, two positions shifted by 180 degrees) in the cylindrical portion 21A. There is. The left end of the insertion hole 21D forms a recess 21E that is depressed from the right side of the bottom 21B to the left. A guide portion 21F exposed in the insertion hole 21D is provided midway through the cylindrical portion 21A in the left-right direction. An example of the guide portion 21F is a cylindrical shaft extending in the tangential direction of the circular insertion hole 21D.

A through hole 21G passing through the bottom 21B in the left-right direction is formed in the bottom 21B. The right end portion of the drawbar 12 is inserted into the through hole 21G. A through hole 21H passing through the partition 21C in the left-right direction is formed in a central portion of the partition 21C that overlaps with the central axis J. The bottom part 21B is fixed to the first part 13 of the spindle 11 by a bolt B2. Thereby, the entire case 21 is fixed to the spindle 11. The case 21 has a cylindrical sleeve 21I into which the root portion of the shaft of the bolt B2 is inserted. A hole 21J is formed in the partition portion 21C to accommodate the head of the bolt B2 and the right end of the sleeve 21I.

The number of swivel shafts 22 is the same as that of the insertion holes 21D of the cylindrical portion 21A (two in this embodiment). Each swivel shaft 22 has a cylindrical shaft portion 22A that extends in the left-right direction and is inserted into the insertion hole 21D, and a claw portion 22B that is arranged on the right side of the insertion hole 21D and fixed to the shaft portion 22A with a bolt B3. and has. A guide surface 22C is formed in the middle of the shaft portion 22A in the left-right direction by cutting out a part of its outer peripheral surface. The guide surface 22C is in contact with the guide portion 21F exposed within the insertion hole 21D of the case 21. A recess 22D recessed toward the central axis K of the shaft 22A is formed at the left end of the outer peripheral surface of the shaft 22A. The claw portion 22B includes a cylindrical portion 22E disposed coaxially with the shaft portion 22A, and a protruding portion 22F protruding from one location on the outer peripheral surface of the cylindrical portion 22E.

The swivel shaft 22 is rotatable around the central axis K (second central axis) while sliding in the left-right direction. The swivel shaft 22 shown in FIG. 1 is in a clamping position to clamp the outer peripheral portion 2E of the test object 2. The clamp position is the left end of the horizontal sliding range of the swivel shaft 22, and in the swivel shaft 22 in the clamp position, the protruding part 22F of the claw part 22B faces the central axis J of the rotating part 3 (Fig. 3 (See also the protrusion 22F indicated by a solid line in .).

When the swivel shaft 22 slides to the right (the other direction) from the clamp position, the guide surface 22C of the swivel shaft 22 that is in contact with the guide portion 21F of the case 21 receives a force in the rotational direction Q around the central axis K from the guide portion 21F. This causes the swivel shaft 22 to rotate. When the swivel shaft 22 slides to the right end of its sliding range, the swivel shaft 22 is placed in the release position where it releases the clamp on the outer circumference 2E of the test object 2 (the protrusion indicated by the chain double-dashed line in FIG. 3). (See section 22F). When the swivel shaft 22 slides to the left (one direction) from the release position, the guide surface 22C receives a force in the opposite direction from the guide portion 21F, causing the swivel shaft 22 to rotate in the opposite direction. The guide surface 22C is configured in a known shape so as to convert the sliding of the swivel shaft 22 into rotation in the rotational direction Q in this manner. Furthermore, when the swivel shaft 22 moves between the clamp position and the release position, the protrusion 22F rotates, for example, 72 degrees in the rotation direction Q.

The tip fitting 23 includes a circular tube portion 23A disposed coaxially with the drawbar 12, a columnar tip portion 23B coaxially fixed to the right end of the circular tube portion 23A, and a circular tube portion 23A arranged coaxially with the drawbar 12, and a columnar tip portion 23B coaxially fixed to the right end of the circular tube portion 23A. It has a spherical part 23C provided on the outer peripheral surface in the middle. The left end portion of the circular tube portion 23A is inserted into the through hole 21G of the bottom portion 21B of the case 21. The circular tube portion 23A is fixed to the right end portion of the drawbar 12 by a bolt B4 passed through the inside thereof. Thereby, the entire tip fitting 23 can slide in the left-right direction together with the drawbar 12. The sliding range of the end fitting 23 in the left-right direction is, for example, about ten millimeters.

The left end of the sliding range of the tip fitting 23 is referred to as a retracted position, and the right end of the sliding range of the tip fitting 23 is referred to as an advanced position. The tip fitting 23 shown in FIG. 1 is in the retracted position. The right end portion of the circular tube portion 23A is inserted into the through hole 21H of the partition portion 21C of the case 21. The distal end portion 23B has a smaller diameter than the circular tube portion 23A, and is fixed to the circular tube portion 23A by, for example, screwing. The tip portion 23B is disposed on the right side of the partition portion 21C within the case 21. The spherical portion 23C has an annular shape covering the entire area in the circumferential direction S of the outer circumferential surface of the circular tube portion 23A, and bulges outward in the radial direction R perpendicular to the central axis J in an arc shape.

The connecting member 24 has a cylindrical central portion 24A disposed coaxially with the tip fitting 23, and an extending portion 24B extending outward in the radial direction R from the central portion 24A. The inner circumferential surface 24C of the center portion 24A is an arcuate surface having approximately the same curvature as the spherical portion 23C of the tip fitting 23, and is in surface contact with the spherical portion 23C while surrounding the spherical portion 23C. Thereby, the entire connecting member 24 is slidable in the left-right direction together with the drawbar 12 and the end fitting 23. Note that the connecting member 24 can change its posture slightly by displacing along the spherical portion 23C. The outer end in the radial direction R of the extended portion 24B is a tip portion 24D that is tapered one step in the left-right direction, and is inserted into the recess 22D of the shaft portion 22A of the corresponding swivel shaft 22. Thereby, the connecting member 24 is connected to each swivel shaft 22. Therefore, when the connecting member 24 slides in the left-right direction together with the drawbar 12 and the end fitting 23, all the swivel shafts 22 rotate in the rotation direction Q while sliding in the left-right direction. When the tip fitting 23 slides to the left retracted position, the swivel shaft 22 is placed in the clamp position, and when the connecting member 24 slides to the right extended position, the swivel shaft 22 is placed in the release position. Note that the tip 24D is inserted into the recess 22D with play in the rotational direction Q so that the swivel shaft 22 can rotate smoothly.

The stage change unit 25 includes a disc-shaped main body 31 coaxially fixed to the right end of the case 21, a cylindrical collet 32 fixed to the main body 31, and a mandrel 33 housed in the collet 32. . The stage changing unit 25 includes a fixed part 34 fixed to the mandrel 33, a biasing member 35 that biases the fixed part 34 to the left side, and a cylinder fixed to the main body 31 and housing the fixed part 34 and the biasing member 35. It includes a stopper 36 having a shape.

Referring to FIG. 2, which shows an enlarged view of the area around the changeover unit 25 in FIG. A cylindrical portion 31B that protrudes to the left side while edging the cylindrical portion 31B is provided. The internal space of the cylindrical portion 31B is a part of the insertion hole 31A. The outer peripheral portion 31C of the main body 31 is fitted into an annular recess 21K provided on the inner peripheral surface of the right end portion of the cylindrical portion 21A of the case 21. The recess 21K is defined by a flat surface 21L that flatly extends outward in the radial direction R from the inner circumferential surface of the cylindrical portion 21A, and a tapered surface 21M that extends to the right while increasing its diameter from the outer edge of the flat surface 21L. The left surface of the outer peripheral portion 31C is in contact with the flat surface 21L from the right side. The outer circumferential surface 31D of the outer circumferential portion 31C is a tapered surface parallel to the tapered surface 21M, and is in surface contact with the tapered surface 21M. Thereby, the entire stage changing unit 25 including the main body 31 is positioned coaxially with respect to the rotating part 3.

A support portion 31E that protrudes to the right is provided on the right surface of the outer peripheral portion 31C. A plurality of support parts 31E may be provided and arranged in line in the circumferential direction S, or may be formed in an annular shape extending in the circumferential direction S. The outer peripheral portion 31C is provided with one or more positioning pins P1 that protrude to the right from the support portion 31E. The outer peripheral portion 31C is fixed to the right end portion of the cylindrical portion 21A of the case 21 with a bolt B5. As a result, the entire stage changing unit 25 including the main body 31 is fixed to the case 21 and further fixed to the spindle 11 via the case 21. In addition, in FIG. 2, the positioning pin P2 that positions the case 21 and the main body 31 in the circumferential direction S and the bolt B5 are shown side by side in half.

The collet 32 is a cylindrical body arranged coaxially with the main body 31. The collet 32 integrates an annular base portion 41, a cylindrical grip portion 42 fitted into the inner peripheral portion 2B of the test object 2, and an intermediate portion 43 between the base portion 41 and the grip portion 42. has.

The base portion 41 is fixed to the main body 31 by bolts B6 while being fitted into a recess 31F recessed to the left side while edging the insertion hole 31A on the right side of the main body 31. Thereby, the entire collet 32 is fixed to the main body 31 and further attached to the spindle 11 via the main body 31 and the case 21. The outer diameter of the outer circumferential surface 42A of the grip portion 42 is constant over almost the entire area. The right end portion of the outer circumferential surface 42A may become smaller in diameter toward the right side so that it can easily fit into the inner circumferential portion 2B of the test object 2. The inner circumferential surface 42B of the grip portion 42 is a tapered surface that becomes larger in diameter toward the right side. The middle part 43 has a cylindrical shape, for example, and extends from the inner peripheral part of the base part 41 to the right side and is connected to the grip part 42 .

A plurality of grooves 32A are formed in the collet 32, which are arranged in the circumferential direction of the gripping portion 42 (same as the circumferential direction S described above) (see FIG. 3). Each groove 32A is a slit that passes through the grip portion 42 and the intermediate portion 43 along the radial direction of the grip portion 42 (same as the radial direction R described above) and the left-right direction. In this embodiment, six grooves 32A are formed at equal intervals in the circumferential direction S. The grip portion 42 can be expanded or contracted according to changes in the groove width W (see FIG. 3) of each groove 32A. Specifically, as the groove width W widens, the diameter of the grip portion 42 increases, and as the groove width W narrows, the diameter of the grip portion 42 decreases. In the dynamic balance tester 1 in a standby state, the grip portion 42 is in a reduced diameter state. In such a collet 32, the base part 41 is a fixed end, and the grip part 42 and the middle part 43 are free ends.

The mandrel 33 has a cylindrical shaft portion 33A disposed coaxially with the collet 32 and extending in the left-right direction, and a tip portion 33B connected to the right end portion of the shaft portion 33A. The shaft portion 33A is surrounded by the base portion 41 and the middle portion 43 of the collet 32. The left end portion of the shaft portion 33A is disposed on the left side of the base portion 41. The tip portion 33B has a truncated conical shape whose diameter gradually increases toward the right side from the right end of the shaft portion 33A, and its outer peripheral surface 33C is a tapered surface whose diameter increases toward the right side. It is surrounded by the inner circumferential surface 42B of the grip part 42 and is in surface contact with the inner circumferential surface 42B.

The fixing portion 34 includes a cylindrical portion 34A disposed coaxially with the mandrel 33, and an annular flange portion 34B extending outward in the radial direction R from the left end of the cylindrical portion 34A. The cylindrical portion 34A is inserted into the insertion hole 31A of the main body 31. The center portion of the cylindrical portion 34A and the left end portion of the shaft portion 33A of the mandrel 33 are fixed by, for example, screws. The fixed part 34 can slide in the left-right direction together with the mandrel 33 by having the cylindrical part 34A guided by the inner peripheral surface of the cylindrical part 31B of the main body 31. When the flange portion 34B contacts the left end portion of the cylindrical portion 31B, the fixed portion 34 and the mandrel 33 are prevented from sliding further to the right.

The biasing member 35 is a coil spring wound around the cylindrical portion 31B of the main body 31, and is expandable and contractible in the left-right direction, and is compressed between the main body 31 and the flange portion 34B of the fixed portion 34. Therefore, the biasing member 35 always biases the mandrel 33 and the fixing portion 34 to the left.

The stopper 36 has a disk portion 36A disposed coaxially with the mandrel 33, and a cylindrical portion 36B extending to the right from the outer periphery of the disk portion 36A. The disk portion 36A faces the fixed portion 34 from the left side. A through hole 36C is formed in the center of the disk portion 36A, into which the tip 23B of the tip fitting 23 can enter when it is in the extended position. The cylindrical portion 36B surrounds the fixing portion 34 and the biasing member 35 and is fixed to the main body 31 with bolts B7. Thereby, the entire stopper 36 is fixed to the main body 31. An annular positioning portion 31G is provided on the left surface of the main body 31 to position the cylindrical portion 36B in the radial direction R by surrounding the right end portion of the cylindrical portion 36B. When the fixing part 34 comes into contact with the right side of the disc part 36A, the fixing part 34 and the mandrel 33 are prevented from sliding further to the left.

In the dynamic balance tester 1 in the standby state, the tip fitting 23 is in the advanced position, and the tip 23B of the tip fitting 23 enters the through hole 36C of the disk portion 36A of the stopper 36 and pushes the fixed part 34 to the right side. . Therefore, the fixed part 34 is separated from the disk part 36A by, for example, about 1 mm to the right (not shown). In this state, the grip portion 42 of the collet 32 is in the reduced diameter state as described above, and each swivel shaft 22 is in the release position.

When performing a dynamic balance test on the test object 2 in the dynamic balance tester 1, in preparation, the test object 2 is set from the right side onto the collet 32 of the dynamic balance tester 1 in a standby state. Since each swivel shaft 22 is in the release position, the protruding portion 22F of the claw portion 22B of each swivel shaft 22 is retracted so as not to disturb the test object 2 set in the collet 32 (two points in FIG. 3). (See the protrusion 22F indicated by the chain line). In the collet 32 in which the test object 2 is set, the grip part 42 is inserted into the reference hole 2C of the test object 2 and fitted into the inner peripheral part 2B of the test object 2. The inner diameter of the inner circumferential portion 2B (specifically, the sleeve 2D) is slightly larger than the outer diameter of the outer circumferential surface 42A of the grip portion 42 in the reduced diameter state. Therefore, the test object 2 is still in an unclamped state when gripped by the collet 32. Further, the test object 2 is positioned in the left-right direction by the outer peripheral part 2E contacting the support part 31E of the main body 31 from the right side, and the positioning pin P1 of the main body 31 is inserted into the positioning hole 2F of the outer peripheral part 2E. As a result, it is positioned in the circumferential direction S.

Next, the aforementioned actuator (not shown) is activated to slide the drawbar 12 to the left. As a result, the distal end fitting 23, which has been in the advanced position until now, slides to the left together with the drawbar 12, so that the distal end portion 23B of the distal end fitting 23 separates from the fixing portion 34 to the left. As a result, the fixing portion 34, which has been pushed to the right by the tip portion 23B, is shifted to the left by the urging force of the urging member 35. Along with this, the mandrel 33 fixed to the fixed part 34 also shifts to the left. At this time, the tapered outer circumferential surface 33C of the tip 33B of the mandrel 33 moves to the left relative to the tapered inner circumferential surface 42B of the grip part 42 of the collet 32. Then, in the collet 32, the outer circumferential surface 33C bends outward in the radial direction R due to the force that tries to spread the inner circumferential surface 42B, thereby widening the groove width W of each divided groove 32A. Therefore, the grip portion 42 expands in diameter and is press-fitted into the sleeve 2D at the inner peripheral portion 2B of the test object 2, thereby gripping the inner peripheral portion 2B.

Further, when the distal end fitting 23 slides to the left from the advanced position, the distal end portion 23B comes off from the through hole 36C of the stopper 36 to the left. In addition, each swivel shaft 22 that has been in the release position until now rotates while sliding to the left in response to the slide of the tip fitting 23. As a result, the protruding portion 22F of the claw portion 22B of each swivel shaft 22 approaches the right surface of the outer peripheral portion 2E of the test object 2 from the right side and from the outside in the radial direction R. When the tip fitting 23 slides to the retracted position, each swivel shaft 22 is placed in the clamp position, and the protruding portion 22F of each swivel shaft 22 presses the right surface of the outer peripheral portion 2E of the test object 2 from the right side. As a result, the outer peripheral part 2E of the test object 2 is clamped by being sandwiched from both sides in the left and right direction between the protruding part 22F of each swivel shaft 22 and the support part 31E of the main body 31 (state in FIG. 2). . In this case, the claw portion 22B and the support portion 31E constitute a fixing portion 45 to which the outer peripheral portion 2E is fixed. Note that if there is a delay in the movement of one of the swivel shafts 22 and the protruding parts 22F of all the claw parts 22B do not press the right side of the outer peripheral part 2E of the test object 2 from the right side at the same time, as described above, By changing the posture of the connecting member 24, the tip end 24D of the extension part 24B is shifted to the left, so that the swivel shaft 22, which has been delayed in movement, is reliably moved to the clamp position.

As a result of the above, the test object 2 is clamped at both the inner peripheral part 2B and the outer peripheral part 2E. Therefore, the test object 2 is connected via the collet 32 to the rotating part 3 of the dynamic balance tester 1 so as to be able to rotate integrally therewith. 1 and 3 show the dynamic balance testing machine 1 when a test object 2 is clamped. Note that, since the disk portion 36A of the stopper 36 contacts the fixing portion 34 from the left side, the fixing portion 34 is restricted from shifting further to the left.

In the dynamic balance testing machine 1 in which the test object 2 is clamped, the rotating section 3 is driven and rotated at a predetermined speed (for example, 4000 rpm) by the aforementioned driving section (not shown), and the vibration of the test object 2 in this state is , is detected by the aforementioned detection section (not shown). The unbalance of the test object 2 is obtained from the detected vibrations.

When the dynamic balance testing machine 1 has finished measuring the unbalance of the test object 2, the above-described actuator is activated to slide the drawbar 12 to the right to its original standby position (not shown). In response, the tip fitting 23 slides from the retracted position to the right. Then, each swivel shaft 22 that has been in the clamp position until now rotates backward while sliding to the right in response to the slide of the tip fitting 23, and is placed in the release position. As a result, the claws 22B of each swivel shaft 22 are disengaged from the right side of the outer circumference 2E of the test object 2 to the right and to the outside in the radial direction R, so that the clamp on the outer circumference 2E of the test object 2 is released.

Then, when the tip fitting 23 further slides to the right to the advanced position, the tip 23B of the tip fitting 23 enters the through hole 36C of the stopper 36 and presses the fixing part 34 to the right (as indicated by the two-dot chain line in Fig. 2). (See tip fitting 23). Then, the fixing portion 34 moves to the right side together with the mandrel 33 against the urging force of the urging member 35. As a result, the force exerted by the outer circumferential surface 33C of the tip end 33B of the mandrel 33 to push and spread the inner circumferential surface 42B of the gripping part 42 of the collet 32 is weakened. Therefore, as the gripping portion 42 bends inward in the radial direction R in an attempt to restore its original shape, the groove width W of each split groove 32A becomes narrower, so that the gripping portion 42 is reduced in diameter. As a result, the press-fitting state of the grip portion 42 into the inner peripheral portion 2B of the test object 2 is released, so that the test object 2 becomes an unclamped state. In this state, the test object 2 can be removed from the collet 32 for replacement. Note that when the type of the test object 2 changes due to replacement, at least the main body 31 and the like in the stage change unit 25 are also replaced with those corresponding to the type of the test object 2.

The tip fitting 23, the mandrel 33, the fixing part 34, and the biasing member 35 as described above constitute an expansion/contraction mechanism 46 that expands/contracts the grip part 42 of the collet 32. The expansion/contraction mechanism 46 is a part of the test object fixing device 4. The drawbar 12 may be considered part of the expansion/contraction mechanism 46.

As described above, in the test object fixing device 4, the outer peripheral part 2E of the test object 2 remote from the reference hole 2C located at the center of rotation is fixed to the fixing part 45, and the cylindrical grip part of the collet 32 42 is inserted into the reference hole 2C, expands in diameter, and is press-fitted into the reference hole 2C, thereby gripping the inner peripheral portion 2B of the test object 2 in the reference hole 2C. When both the inner circumferential portion 2B and the outer circumferential portion 2E of the test object 2 are fixed in this manner, the test object 2 is likely to be arranged concentrically with the test object fixing device 4 and the rotating section 3. In particular, since the collet 32 is a centripetal collet having a function of centering the test object 2, the test object 2 is arranged concentrically with high precision. Therefore, the mounting error of the test object 2 to the test object fixing device 4 and the rotating part 3 can be suppressed, and the measurement accuracy of unbalance in the dynamic balance tester 1 can be improved. Further, since the dispersion in the unbalance measurement results for the same test object 2 is reduced, the reproducibility of the measurement results can also be improved.

This invention is not limited to the embodiments described above, and various changes can be made within the scope of the claims.

In the embodiment described above, the outer peripheral part 2E of the test object 2 is fixed to the fixing part 45 of the test object fixing device 4 between the tip part 22F of the claw part 22B of the swivel shaft 22 and the support part 31E of the main body 31. This is realized by clamping the outer peripheral portion 2E at. The movement of the swivel shaft 22 between the release position and the clamp position is not limited to a combination of sliding in the left and right direction and rotation around the central axis K, but may be movement according to an arbitrary trajectory linked to the sliding of the tip fitting 23. It's fine. Further, the outer circumferential portion 2E may be fixed by being screwed to the outer circumferential portion 31C of the main body 31, for example, by an operator. Furthermore, the outer circumferential portion 2E does not have to be the outermost portion of the test object 2 in the radial direction R.

Furthermore, although the test object 2 in this embodiment is a rubber coupling 2A made of rubber and having a built-in resin sleeve 2D, the material of the test object 2 can be changed arbitrarily.

In the above description, the spindle 11 and the drawbar 12 are arranged horizontally so that the central axis J of the rotating section 3 extends horizontally, but the spindle 11 and the drawbar 12 are arranged vertically so that the central axis J extends vertically. may be placed in

1 Dynamic balance tester 2 Test object 2B Inner peripheral part 2C Reference hole 2E Outer peripheral part 3 Rotating part 4 Test object fixing device 32 Collet 32A Split groove 42 Gripping part 45 Fixed part 46 Expansion/contraction mechanism S Circumferential direction W (split groove 32A ) Groove width

Claims (2)

The main body and
a fixing part that is rotatable and has a reference hole formed at the center of rotation, and clamps an outer peripheral portion of the test object that is remote from the reference hole;
A cylindrical grip part that is inserted into the reference hole and grips the inner peripheral part of the test object in the reference hole, wherein a plurality of grooves are formed in line in the circumferential direction of the grip part, and the grooves are arranged in a circumferential direction of the grip part. a collet fixed to an end surface of the main body, the collet having a gripping part that can be expanded and contracted according to changes in the groove width of the main body ;
an expansion and contraction mechanism that expands and contracts the gripping part ,
The fixing part is
a support portion formed on the end surface of the main body;
a claw portion that can clamp the outer peripheral portion between the support portion and the collet in a first direction along the first central axis of the collet;
The expansion/contraction mechanism is
a drawbar that slides in the first direction;
a tip metal fitting that is slidable in the first direction along with the drawbar;
a mandrel having an outer circumferential surface in contact with the gripping portion of the collet, the mandrel sliding in the first direction along with the tip fitting, and sliding in one direction included in the first direction to a mandrel that expands the diameter of the gripping portion and slides in the other direction included in the first direction and opposite to the one direction to reduce the diameter of the gripping portion of the collet;
a shaft part to which the claw part is fixed and extends in the first direction and is slidable in the first direction, the shaft part being slidable in the one direction included in the first direction; a shaft portion that rotates in one rotational direction and rotates in the opposite rotational direction around the second central axis as the shaft portion slides in the other direction included in the first direction;
further comprising a connecting member that connects the shaft portion and the tip fitting so that the shaft portion slides in the first direction as the tip fitting slides in the first direction;
As the tip fitting slides in the one direction, the shaft portion slides in the one direction, so that the claw portion faces the support portion in the other direction, and is spaced between the support portion and the support portion. When the shaft portion slides in the other direction as the tip fitting slides in the other direction, the claw portion is moved toward the clamp position. A test object fixing device for a dynamic balance tester, which is located at a release position rotated about the second central axis and spaced apart from the clamp position in the other direction. A test object fixing device according to claim 1;
A dynamic balance testing machine comprising: a rotating part to which the test object fixing device is attached and rotates in the circumferential direction.

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