CN214842980U

CN214842980U - Shaft workpiece key groove symmetry measuring device

Info

Publication number: CN214842980U
Application number: CN202121668508.0U
Authority: CN
Inventors: 华古春; 陈阳; 程秀秀
Original assignee: Dongyang Linix Machine Electricity Co Ltd
Current assignee: Dongyang Linix Machine Electricity Co Ltd
Priority date: 2021-07-22
Filing date: 2021-07-22
Publication date: 2021-11-23
Anticipated expiration: 2031-07-22

Abstract

The utility model relates to an axle type work piece keyway symmetry measuring device belongs to keyway symmetry and measures technical field. The utility model provides an axle type work piece keyway symmetry measuring device, includes the base, be equipped with on the base and be used for the clamping mechanism of fixing the work piece level, still be equipped with on the base and be used for making the terminal surface keep horizontally stop gear about the work piece keyway, stop gear is including the translation seat that can be for work piece axial direction parallel movement and can be relative the gag lever post that translation seat oscilaltion and level set up, the gag lever post by indirect or direct rotation support in on the translation seat, the activity be equipped with on the base with the tongue of gag lever post homonymy. The utility model has the advantages of can make level the orientation of adjusting the work piece rapidly when carrying out the measurement of second time to the time of making level when can shortening the measurement of second time, the simplified operation improves measuring efficiency.

Description

Shaft workpiece key groove symmetry measuring device

Technical Field

The utility model relates to an axle type work piece keyway symmetry measuring device belongs to keyway symmetry and measures technical field.

Background

At present, two methods are mainly used for measuring the symmetry error of the key groove of the shaft workpiece, namely a three-coordinate measuring method and a positioning block method (or called a pseudo key method). The positioning block method is used for carrying out measurement twice, namely, the measured workpiece is turned by 180 degrees and then is subjected to measurement for the second time, and then the difference value of the two measurement values is substituted into a formula for calculation. The existing Chinese patent No. 201110181957.7, the patent name of which is a coupling key groove symmetry degree detection method, discloses a coupling key groove symmetry degree detection method, which has the beneficial effects that a pentahedron processing machine tool workbench is adopted as a detection platform, and because the pentahedron processing machine tool is high in parallel precision with a cross beam, the influence of the precision of a conventional common detection platform body on detection can be effectively avoided. It also has the following disadvantages: the steps of the first measurement still need to be repeated for leveling when the workpiece is turned for 180 degrees and then the second measurement is carried out, so that the operation is complex, the measurement efficiency is low and the like.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an axle type work piece keyway symmetry measuring device, the step when still needing repeated first measurement to make level when having solved the work piece upset 180 back that exists among the prior art and carrying out the second measurement, complex operation, measurement of efficiency low scheduling problem.

The above technical purpose of the present invention is mainly solved by the following technical solutions: the utility model provides an axle type work piece keyway symmetry measuring device, includes the base, be equipped with on the base and be used for the clamping mechanism of fixing the work piece level, still be equipped with on the base and be used for making the terminal surface keep horizontally stop gear about the work piece keyway, stop gear is including the translation seat that can be for work piece axial direction parallel movement and can be relative the gag lever post that translation seat oscilaltion and level set up, the gag lever post by indirect or direct rotation support in on the translation seat, the activity be equipped with on the base with the tongue of gag lever post homonymy.

When the device is used, firstly, the workpiece is horizontally fixed preliminarily by the clamping mechanism, then the translation seat is controlled to move in parallel relative to the axial direction of the workpiece, the limiting rod is enabled to be just opposite to the keyway of the workpiece, then the limiting rod is controlled to rotate to enable the end part of the limiting rod to extend into the keyway of the workpiece, then the limiting rod is controlled to move upwards and simultaneously adjust the orientation of the workpiece until the top surface of the end part of the limiting rod is tightly attached to the upper end surface of the keyway of the workpiece to finish leveling, the workpiece is fixedly locked by the clamping mechanism after leveling, then the measuring end of the height gauge is adjusted to be at the same height as the axial line of the workpiece, then the measuring end of the height gauge is controlled to extend into the keyway of the workpiece, then the measuring end of the height gauge is controlled to fall to be in contact with the lower end surface of the keyway of the workpiece, the measured value is recorded, then the measuring end of the height gauge is controlled to be reset to be at the same height as the axial line of the workpiece, and the limiting rod is controlled to rotate to enable the end part of the limiting rod to move out of the keyway of the workpiece, the height position of the limiting rod is kept unchanged all the time, then the workpiece is horizontally fixed by the clamping mechanism again after being turned for 180 degrees, then the translation seat is controlled to move axially and parallelly relative to the workpiece, so that the limiting rod is just opposite to the keyway of the workpiece, then the limiting rod is controlled to rotate so that the end part of the limiting rod extends into the keyway of the workpiece, then the orientation of the workpiece is rapidly adjusted according to the height of the limiting rod until the top surface of the end part of the limiting rod is tightly attached to the upper end surface of the keyway after the workpiece is turned for 180 degrees to finish leveling, then the measuring end of the height gauge is controlled to extend into the keyway of the workpiece, then the measuring end of the height gauge is controlled to descend to be contacted with the lower end surface of the keyway after the workpiece is turned for 180 degrees, the measured value is recorded, the symmetry degree of the keyway of the workpiece can be measured, the symmetry degree is the absolute value of the difference of the two measured values, therefore, the symmetry degree error of the keyway of the workpiece can be conveniently and can be measured, and the height position of the limiting rod is kept unchanged during the second measurement, the orientation of the workpiece can be rapidly adjusted to be leveled, so that the leveling time during the second measurement can be shortened, the operation is simplified, and the measurement efficiency is improved.

Preferably, the limiting mechanism further comprises a guide rail which is fixedly arranged on the base and is axially parallel to the workpiece, the translation seat is slidably supported on the guide rail, a rotating seat which extends upwards is rotatably arranged at the top of the translation seat, a vertically arranged supporting rod is fixedly arranged on the rotating seat, and the limiting rod is slidably supported on the supporting rod.

Through still being equipped with in stop gear and setting firmly on the base and with work piece axial direction parallel's guide rail, translation seat is supported on the guide rail by sliding, translation seat top rotates and is equipped with the roating seat that upwards extends, the bracing piece of vertical setting has set firmly on the roating seat, the gag lever post is supported on the bracing piece by sliding, make the guide rail can play the effect of direction when translation seat removes, guarantee the precision of removal, thereby guarantee measuring precision, the gag lever post can be along the bracing piece oscilaltion simultaneously, so that during the measurement the gag lever post can closely laminate with the upper and lower terminal surface of work piece keyway and make level, improve measuring precision, and can be applicable to the keyway of different width and make level, the gag lever post can carry out rotary motion round the roating seat in addition, be convenient for will be surveyed work piece upset 180 when carrying out the second measurement.

Preferably, the limiting mechanism further comprises a transversely arranged limiting pin, one end of the limiting pin penetrates through the limiting rod and is abutted against the side face of the supporting rod, and the limiting pin is in threaded fit with the limiting rod.

Through still being equipped with the spacer pin of horizontal setting in stop gear, spacer pin one end run through the gag lever post and with bracing piece side butt, gag lever post and gag lever post screw-thread fit for can fix the high position of gag lever post through gag lever post and bracing piece side butt, make the gag lever post can keep the state of closely laminating with the upper and lower terminal surface of work piece keyway respectively.

Preferably, the clamping mechanism comprises two opposite thimble chucks, a clamping space for the horizontal placement of the workpiece is formed between the two thimble chucks, and the two thimble chucks can be close to or far away from each other along the axial direction of the workpiece.

Through be equipped with the thimble chuck of two relative settings in clamping mechanism, be formed with the clamping space that supplies the work piece level to place between two thimble chucks, two thimble chucks can be close to or keep away from each other along the axial of work piece for the work piece level can be controlled two thimble chucks and be close to each other when placing in the clamping space and carry out the butt with the both ends of work piece and realize the clamping, thereby can be fixed with the work piece level, and can be applicable to and carry out the clamping to the work piece of different length.

Preferably, the clamping mechanism further comprises two clamping seats which can be close to or far away from each other along the axial direction of the workpiece, each clamping seat is provided with a through hole which horizontally penetrates through two ends of each clamping seat, and the thimble chucks horizontally penetrate through the through holes and are in sliding connection with the through holes.

Through still being equipped with two clamping seats that can be close to each other or keep away from along the axial of work piece in clamping mechanism, the clamping seat has the level and runs through the through-hole at clamping seat both ends, thimble chuck level passes the through-hole and rather than sliding connection, make can be close to each other or keep away from two thimble chucks of drive and be close to each other or keep away from through controlling clamping seat, be applicable to and adjust the clamping when being surveyed work piece length variation great, thimble chuck can move in the through-hole horizontal translation in addition, be convenient for can carry out the clamping fast after being surveyed work piece upset 180 when measuring for the second time, be applicable to simultaneously and adjust the clamping when being surveyed work piece length variation less or unchangeable.

Preferably, a fine adjustment assembly used for adjusting the horizontal movement distance of the thimble chuck in the through hole is arranged on the outer side of the thimble chuck, the fine adjustment assembly comprises a strip-shaped groove communicated with the through hole and the outer part of the through hole, a distance adjusting rod penetrating through the strip-shaped groove is fixedly arranged on the thimble chuck, a pre-tightening groove is communicated with the outer side of the through hole, a limiting protrusion fixedly connected with the thimble chuck is arranged in the pre-tightening groove in a sliding manner, and a pre-tightening spring surrounding the thimble chuck is arranged between the limiting protrusion and the end wall of the pre-tightening groove.

The fine adjustment component for adjusting the horizontal moving distance of the thimble chuck in the through hole is arranged on the outer side of the thimble chuck, the fine adjustment component comprises a strip-shaped groove communicated with the through hole and the outer part of the through hole, a distance adjusting rod penetrating through the strip-shaped groove is fixedly arranged on the thimble chuck, a pre-tightening groove is communicated with the outer side of the through hole, a limiting bulge fixedly connected with the thimble chuck is arranged in the pre-tightening groove in a sliding manner, and a pre-tightening spring surrounding the thimble chuck is arranged between the limiting bulge and the end wall of the pre-tightening groove, so that an operator can pull the distance adjusting rod outwards through manual operation when measuring a workpiece for the second time to compress the pre-tightening spring, the two thimble chucks are mutually far away from each other to cancel clamping the workpiece, therefore, the operator can quickly turn over the measured workpiece by 180 degrees without controlling the two chucks to be mutually far away from each other, the operation is convenient, and simultaneously, the quick clamping can be carried out when measuring the next workpiece with smaller length change or unchanged, the efficiency of measurement is improved; in addition, the workpiece can be preliminarily clamped by the reset force generated by compressing the pre-tightening spring during clamping, so that the orientation of the workpiece can be conveniently adjusted for leveling.

Preferably, the fine adjustment assembly further comprises a locking rod, the end portion of the locking rod can be abutted to the side wall of the thimble chuck, the locking rod extends into the clamping seat and is in threaded fit with the clamping seat, and the other end of the locking rod extends into the outer portion of the clamping seat and is fixedly connected with a locking knob.

Through still being equipped with the locking lever that its tip can with thimble chuck lateral wall butt in the fine setting subassembly, the locking lever stretches into the mount and rather than screw-thread fit, the locking lever other end stretches into outside and the rigid coupling of mount has the locking knob, make and to drive the locking lever rotation through rotating the locking knob, thereby make the tip of locking lever carry out the butt with the lateral wall of thimble chuck or break away from the butt, so that carry out spacingly to the position of thimble chuck when the clamping, realize stabilizing the clamping, can adjust the position of thimble chuck after once measuring the completion in addition, so that dismantle the work piece or upset clamping.

Preferably, the clamping mechanism further comprises a positioning assembly for fixing the clamping seat on the base, the positioning assembly comprises a stop block fixedly arranged at the top of the rear end of the base, the rear end of the clamping seat is in contact with the stop block, the base is provided with a top opening and penetrates through chutes at the left end and the right end of the base, a positioning rod is arranged on the front side of the clamping seat and penetrates through the clamping seat and is in threaded connection with the clamping seat, one end of the positioning rod extends into the chute and is fixedly connected with a positioning block matched with the chute, and the other end of the positioning rod extends into a positioning knob outside the clamping seat and fixedly connected with the clamping seat.

The clamping mechanism is also internally provided with a positioning component used for fixing the clamping seat on the base, the positioning component comprises a stop block fixedly arranged at the top of the rear end of the base, the rear end of the clamping seat is contacted with the stop block, the base is provided with a chute with an open top and penetrates through the left end and the right end of the base, the front side of the clamping seat is provided with a positioning rod, the positioning rod penetrates through the clamping seat and is in threaded connection with the clamping seat, one end of the positioning rod extends into the chute and is rotatably connected with a positioning block contacted with the chute wall, the other end of the positioning rod extends out of the clamping seat and is fixedly connected with a positioning knob, so that the rear end of the clamping seat can be limited by the stop block, the clamping seat can be fixed on the base through the matching between the positioning block and the chute wall, the stable clamping of a workpiece is convenient to realize, when the relative positions of the two clamping seats need to be adjusted, an operator can separate the positioning block from the chute wall, therefore, the fixing of the clamping seats can be cancelled, so that an operator can adjust the relative positions of the two clamping seats to clamp workpieces with different lengths.

Therefore, the utility model has the advantages of can adjust the orientation of work piece rapidly when carrying out the second measurement and make level to the time of making level when can shortening the second measurement, the simplified operation improves measuring efficiency.

Drawings

Fig. 1 is a schematic perspective view of the present invention;

FIG. 2 is a schematic cross-sectional view of the fine adjustment assembly of the present invention;

fig. 3 is a schematic side view of the positioning assembly of the present invention.

The scores in the figures are as follows: 1. a clamping mechanism; 2. a limiting mechanism; 3. a translation seat; 4. a limiting rod; 5. a height gauge; 6. a base; 7. a guide rail; 8. a rotating base; 9. a support bar; 10. a spacing pin; 11. a thimble clamping head; 12. installing a clamping seat; 13. a through hole; 14. a fine tuning component; 15. a strip-shaped groove; 16. a distance adjusting rod; 17. a clamping space; 18. pre-tightening the groove; 19. a limiting bulge; 20. pre-tightening the spring; 21. a locking lever; 22. a locking knob; 23. a positioning assembly; 24. a stopper; 25. a chute; 26. positioning a rod; 27. positioning blocks; 28. and positioning the knob.

Detailed Description

The technical solution of the present invention is further specifically described below by way of examples and with reference to the accompanying drawings.

As shown in fig. 1, the utility model discloses an axle type work piece keyway symmetry measuring device, including base 6, be equipped with on the base 6 and be used for the clamping machine 1 fixed with the work piece level, clamping machine 1 includes the thimble chuck 11 of two relative settings, be formed with the clamping space 17 that supplies the work piece level to place between two thimble chucks 11, two thimble chucks 11 can be close to or keep away from each other along the axial of work piece, clamping machine 1 still includes two clamping bases 12 that can be close to or keep away from each other along the axial of work piece, clamping base 12 has the level and runs through the through-hole 13 at clamping base 12 both ends, thimble chuck 11 level passes through-hole 13 and rather than sliding connection, clamping machine 1 is still including being used for fixing clamping base 12 the locating component 23 on base 6.

As shown in fig. 3, the positioning assembly 23 includes a stop block 24 fixedly disposed at the top of the rear end of the base 6, the rear end of the holder 12 contacts with the stop block 24, the base 6 has a top opening and runs through a chute 25 at the left and right ends of the base 6, a positioning rod 26 is disposed at the front side of the holder 12, the positioning rod 26 runs through the holder 12 and is in threaded connection with the holder, one end of the positioning rod 26 extends into the chute 25 and is rotatably connected with a positioning block 27 contacting with the chute 25, and the other end of the positioning rod 26 extends into the outside of the holder 12 and is fixedly connected with a positioning knob 28.

As shown in fig. 1, a base 6 is further provided with a limiting mechanism 2 for keeping the upper and lower end surfaces of a keyway of a workpiece horizontal, the limiting mechanism 2 comprises a translation seat 3 capable of moving in parallel in the axial direction of the workpiece and a limiting rod 4 capable of moving up and down and horizontally arranged relative to the translation seat 3, the limiting rod 4 is indirectly or directly rotatably supported on the translation seat 3, a height gauge 5 on the same side as the limiting rod 4 is movably arranged on the base 6, the height gauge 5 is a digital display height gauge, the limiting mechanism 2 further comprises a guide rail 7 fixedly arranged on the base 6 and parallel to the axial direction of the workpiece, the translation seat 3 is slidably supported on the guide rail 7, the top of the translation seat 3 is rotatably provided with an upwardly extending rotary seat 8, a vertically arranged support rod 9 is fixedly arranged on the rotary seat 8, the limiting rod 4 is slidably supported on the support rod 9, the limiting mechanism 2 further comprises a transversely arranged limiting pin 10, one end of the limiting pin 10 penetrates through the limiting rod 4 and abuts against the side surface of the support rod 9, the limit pin 10 is in threaded fit with the limit rod 4.

As shown in fig. 2, a fine adjustment assembly 14 for adjusting the horizontal movement distance of the thimble chuck 11 in the through hole 13 is disposed outside the thimble chuck 11, the fine adjustment assembly 14 includes a strip groove 15 communicating the through hole 13 and the outside of the through hole 13, a distance adjusting rod 16 penetrating through the strip groove 15 is fixedly disposed on the thimble chuck 11, a pre-tightening groove 18 is communicatively disposed outside the through hole 13, a limit protrusion 19 fixedly connected with the thimble chuck 11 is slidably disposed in the pre-tightening groove 18, a pre-tightening spring 20 surrounding the thimble chuck 11 is disposed between the end wall of the limit protrusion 19 and the end wall of the pre-tightening groove 18, the fine adjustment assembly 14 further includes a locking rod 21 whose end can abut against the side wall of the thimble chuck 11, the locking rod 21 extends into the clamping seat 12 and is in threaded engagement with the clamping seat 12, and the other end of the locking rod 21 extends into the outside of the clamping seat 12 and is fixedly connected with a locking knob 22.

In the specific implementation of this embodiment, an operator holds a workpiece by hand and places the workpiece in the clamping space 17, then rotates the positioning knob 28 to separate the positioning block 27 from the slot wall of the chute 25, then manually adjusts the relative positions of the two clamping seats 12 to enable the workpiece to be horizontally placed between the two thimble chucks 11, then manually adjusts the relative positions of the two clamping seats 12 to enable the two thimble chucks to approach each other until the inner ends of the two thimble chucks 11 abut against the two axial ends of the workpiece respectively, at this time, the pre-tightening spring 20 is compressed to store force, primarily clamps the workpiece between the two thimble chucks 11 under the action of the pre-tightening spring 20, enables the axis of the thimble chucks 11 to coincide with the axis of the workpiece and the keyway of the workpiece to face one side of the limiting rod 4, and then controls the translation seat 3 to axially move parallel to the workpiece along the guide rail 7 to enable the limiting rod 4 to face the keyway of the workpiece, rotating the limiting rod 4 around the rotating seat 8 to enable the end part of the limiting rod to extend into the workpiece key groove, controlling the limiting rod 4 to move upwards and simultaneously adjusting the orientation of the workpiece until the top surface of the end part of the limiting rod 4 is tightly attached to the upper end surface of the workpiece key groove to finish leveling, after leveling, rotating the locking knob 22 to enable the end part of the limiting rod to be abutted against the side wall of the thimble chuck 11 to fixedly lock the workpiece, adjusting the measuring end of the height gauge 5 to be at the same height with the axis of the workpiece, controlling the measuring end of the height gauge 5 to extend into the workpiece key groove, controlling the measuring end of the height gauge 5 to descend to be in contact with the lower end surface of the workpiece key groove, recording the measured value, and thus finishing the first measurement of the workpiece key groove;

then the measuring end of the height gauge 5 is controlled to reset to the position with the same height as the axis of the workpiece, the limiting rod 4 is rotated to enable the end part to move out of the keyway of the workpiece, the height position of the limiting rod 4 is kept unchanged all the time, then the locking knob 22 is rotated reversely to enable the end part to be separated from the side wall of the thimble chucks 11 to be abutted, then the distance adjusting rod 16 is pulled outwards to enable the two thimble chucks 11 to be away from each other and then the workpiece to be taken down, the workpiece is manually turned over for 180 degrees to enable the two ends of the workpiece to be interchanged, then the distance adjusting rod 16 is pulled outwards to fix the workpiece between the two thimble chucks 11, the axis of the thimble chucks 11 is enabled to be superposed with the axis of the workpiece and the keyway of the workpiece faces one side of the limiting rod 4, then the translation seat 3 is controlled to move in parallel along the axial direction of the workpiece along the guide rail 7, the limiting rod 4 is enabled to face the keyway of the workpiece, and then the limiting rod 4 rotates around the rotation seat 8 to enable the end part to extend into the keyway of the workpiece, and then, rapidly adjusting the orientation of the workpiece according to the height of the limiting rod 4 until the top surface of the end part of the limiting rod 4 is tightly attached to the upper end surface of the key groove after the workpiece is turned for 180 degrees to finish leveling, controlling the measuring end of the height gauge 5 to extend into the key groove of the workpiece, then controlling the measuring end of the height gauge 5 to descend to be in contact with the lower end surface of the key groove after the workpiece is turned for 180 degrees, and recording the measured value, so that the symmetry degree of the key groove of the workpiece can be measured, wherein the symmetry degree is the absolute value of the difference of the two measured values.

The utility model has the advantages of can make level the orientation of adjusting the work piece rapidly when carrying out the measurement of second time to the time of making level when can shortening the measurement of second time, the simplified operation, and then improve measuring efficiency.

Claims

1. The utility model provides an axle type work piece keyway symmetry measuring device, includes base (6), its characterized in that: the fixture is characterized in that the fixture (1) used for horizontally fixing a workpiece is arranged on the base (6), the base (6) is further provided with a limiting mechanism (2) used for enabling the upper end face and the lower end face of a workpiece key groove to be kept horizontal, the limiting mechanism (2) comprises a translation seat (3) capable of moving axially and parallel relative to the workpiece and a limiting rod (4) capable of moving up and down and horizontally arranged relative to the translation seat (3), the limiting rod (4) is indirectly or directly rotatably supported on the translation seat (3), and a height ruler (5) on the same side with the limiting rod (4) is movably arranged on the base (6).

2. The shaft type workpiece key groove symmetry degree measuring device according to claim 1, characterized in that: stop gear (2) still including set firmly in on base (6) and with work piece axial direction parallel's guide rail (7), translation seat (3) by sliding support in on guide rail (7), translation seat (3) top is rotated and is equipped with roating seat (8) that upwards extend, set firmly bracing piece (9) of vertical setting on roating seat (8), gag lever post (4) by sliding support in on bracing piece (9).

3. The shaft type workpiece key groove symmetry degree measuring device according to claim 2, characterized in that: stop gear (2) still include horizontal spacer pin (10) that sets up, spacer pin (10) one end is run through gag lever post (4) and with bracing piece (9) side butt, gag lever post (10) with gag lever post (4) screw-thread fit.

4. The device for measuring the symmetry degree of the key groove of the shaft workpiece according to claim 1, 2 or 3, is characterized in that: the clamping mechanism (1) comprises two opposite thimble chucks (11), a clamping space (17) for a workpiece to be horizontally placed is formed between the thimble chucks (11), and the thimble chucks (11) can be close to or far away from each other along the axial direction of the workpiece.

5. The shaft type workpiece key groove symmetry degree measuring device according to claim 4, characterized in that: the clamping mechanism (1) further comprises two clamping seats (12) which can be close to or far away from each other along the axial direction of a workpiece, the clamping seats (12) are provided with through holes (13) which penetrate through the two ends of the clamping seats (12) horizontally, and the ejector pin chuck (11) penetrates through the through holes (13) horizontally and is connected with the ejector pin chuck in a sliding mode.

6. The shaft type workpiece key groove symmetry degree measuring device according to claim 5, characterized in that: thimble chuck (11) outside is equipped with and is used for adjusting thimble chuck (11) in horizontal migration distance's in through-hole (13) fine setting subassembly (14), fine setting subassembly (14) is including the intercommunication through-hole (13) with through-hole (13) outside bar groove (15), set firmly on thimble chuck (11) and run through bar (16) of bar groove (15), through-hole (13) outside intercommunication is equipped with pretension groove (18), pretension groove (18) in the sliding fit with spacing arch (19) of thimble chuck (11) rigid coupling, spacing arch (19) with be equipped with between pretension groove (18) the end wall and center on pretension spring (20) of thimble chuck (11).

7. The shaft type workpiece key groove symmetry degree measuring device according to claim 6, characterized in that: the fine adjustment assembly (14) further comprises a locking rod (21) of which the end part can be abutted against the side wall of the thimble chuck (11), the locking rod (21) extends into the clamping seat (12) and is in threaded fit with the clamping seat, and the other end of the locking rod (21) extends into the outer part of the clamping seat (12) and is fixedly connected with a locking knob (22).

8. The shaft type workpiece key groove symmetry degree measuring device according to claim 5, characterized in that: the clamping mechanism (1) also comprises a positioning component (23) used for fixing the clamping seat (12) on the base (6), the positioning component (23) comprises a stop block (24) fixedly arranged at the top of the rear end of the base (6), the rear end of the clamping seat (12) is contacted with the stop block (24), the base (6) is provided with a chute (25) which is provided with an opening at the top and penetrates through the left end and the right end of the base (6), a positioning rod (26) is arranged at the front side of the clamping seat (12), the positioning rod (26) penetrates through the clamping seat (12) and is in threaded connection with the clamping seat, one end of the positioning rod (26) extends into the chute (25) and is rotatably connected with a positioning block (27) which is in contact with the chute wall of the chute (25), the other end of the positioning rod (26) extends into the outside of the clamping seat (12) and is fixedly connected with a positioning knob (28).