Coaxiality measuring machine of piece to be measured

Abstract

The utility model is suitable for the technical field of coaxiality measuring equipment, and provides a coaxiality measuring machine for a piece to be measured, which comprises a driving module, a transmission module, a measuring module and a display module. The driving module comprises a driving motor; the transmission module comprises at least one group of rotors, and each group of rotors comprises two rotors and is used for driving the to-be-tested piece to rotate; the axes of the two rotors in each group are arranged in parallel, and the radial distance between the two rotors is smaller than the radial width of the to-be-tested piece; the driving motor is in transmission connection with the rotor; the measurement module is used for measuring each displacement generated by different points in the circumferential direction of the to-be-measured piece on the measurement module, converting each displacement into each data signal and sending the data signal to the display module; and the display module receives the data signals, converts the data signals into numerical values and displays the numerical values. Therefore, the coaxiality measuring machine provided by the utility model can realize data visualization and improve the measuring efficiency and accuracy. And the data is visualized.

Description

Technical Field

[0001] The utility model relates to the technical field of coaxiality measuring equipment, in particular to a coaxiality measuring machine for a piece to be measured. Background Art

[0002] The electromagnetic switch of the automobile starter motor refers to the control switch on the automobile starter, which is one of the three major components of the starter (DC motor, transmission meshing mechanism and electromagnetic switch). As the name suggests, the electromagnetic switch is a switch controlled by an electromagnet, that is, a combination of an electromagnet and a switch. When the electromagnet coil is energized, an electromagnetic attraction is generated. When the pull rod in the active iron core is pushed or pulled axially, the contact piece at the tail end is connected to the contact surface of the contact bolt in the motor, so that the DC motor is powered on and starts, thereby driving the engine to start. Electromagnetic switches are widely used in various industries.

[0003] The pull rod in the electromagnetic switch of the starting motor is one of the most critical parts of the motor. The pull rod part needs to be assembled with a variety of small parts to form an integrated unit. The entire component needs to perform up and down axial, pull-up and push-down connection and tightening movements, and the coaxiality requirements are very strict.

[0004] The electromagnetic switch pull rod of the starter motor is a special connection part with multiple round rod steps (see Figure 1 as well as Figure 2 ), acting in the steel housing of the automobile starter motor, and assembled and fixed together by air pressure or hydraulic pressure. The tie rod product is completed through multiple processes such as cold heading, stamping, grooving, surface treatment and inspection. Because the entire motor needs to move axially when working after the tie rod is assembled with parts (composed of springs / rubber pads / hardware sheets / motor motor seats / motor housings / copper contacts, etc.), the coaxiality requirements of the tie rod are very strict. If it is unqualified, it will cause jamming during axial operation, and finally cause the motor to break and damage.

[0005] Therefore, the coaxiality quality of the tie rod is a key issue that manufacturers should consider. In the prior art, the coaxiality of the tie rod is measured by the operator holding a mold fixture or a simple coaxiality meter to insert the tie rod, manually read the reading, and manually determine whether the coaxiality is qualified. This process completely relies on the operator's experience. This method has large errors and a high misjudgment rate. It cannot guarantee efficiency and quality, and the process capability is completely uncontrollable. If defective products flow into the client and are installed in the motor, the entire component and the motor will be stuck and short-circuited.

[0006] In summary, the existing structure has obvious inconveniences and defects in actual use, so it is necessary to improve it. Utility Model Content

[0007] In view of the above-mentioned defects, the purpose of the present invention is to provide a coaxiality measuring machine for a workpiece to be measured, which can realize data visualization and improve measurement efficiency and accuracy.

[0008] In order to achieve the above object, the utility model provides a coaxiality measuring machine for a workpiece to be measured, comprising:

[0009] A drive module, including a drive motor;

[0010] The transmission module comprises at least one group of rotors, each group of rotors comprises two rotors, and is used to drive the test piece to rotate; the axes of the two rotors in each group are arranged in parallel, and the radial spacing between the two rotors is smaller than the radial width of the test piece; the driving motor is in transmission connection with the rotors;

[0011] A measuring module, used for measuring the displacements of different points on the circumference of the workpiece to be tested, and converting the displacements into data signals to send to a display module;

[0012] The display module receives each of the data signals and converts each of the data signals into a numerical value for display.

[0013] According to the coaxiality measuring machine of the test piece, the test piece is provided with a plurality of round rods along the axial direction;

[0014] The transmission module is provided with at least two groups of rotors, the position of each group of rotors corresponds to the position of different round rods, and the height difference between the top surfaces of the two groups of rotors is equal to the height difference between the bottom surfaces of the corresponding round rods.

[0015] According to the coaxiality measuring machine for the workpiece to be tested, the transmission module also includes two first gears and a second gear, the second gear meshing between the two first gears; the second gear is transmission connected to the output shaft of the drive motor; the two first gears are transmission connected to the two rotors respectively through a connecting shaft; the two corresponding rotors between the two groups are transmission connected through a connecting shaft.

[0016] According to the coaxiality measuring machine of the workpiece to be measured, it also includes a supporting module, which includes a raising frame, a fixing plate and a mounting frame for mounting the workpiece to be mounted, the fixing plate is arranged on the top surface of the raising frame, and the mounting frame is arranged on the raising frame or the fixing plate; the mounting frame is provided with a plurality of bosses and grooves respectively matched with each of the workpieces to be mounted.

[0017] The drive motor is installed on the mounting frame, the drive motor is located on the left side of the mounting frame, and the output shaft of the drive motor is arranged toward the right side of the mounting frame;

[0018] The rotor is mounted on the mounting frame, and the rotor is located on the right side of the driving motor;

[0019] The measuring module is arranged on the fixing plate or the mounting frame;

[0020] The display module is arranged on the fixing plate or the mounting frame.

[0021] According to the coaxiality measuring machine of the workpiece to be measured, it also includes a first limit member for limiting the axial movement of the workpiece to be measured, and the first limit member is installed on the mounting frame; the first limit member is a screw assembly, and the screw assembly includes a screw and a nut, and the screw is fixed to the mounting frame through the nut.

[0022] According to the coaxiality measuring machine of the workpiece to be measured, it also includes a rocker arm assembly, which includes a rocker arm, a rocker arm base, a rotating shaft and a hydraulic cylinder; the rocker arm is movably installed on the rocker arm base; the hydraulic cylinder is transmission-connected to the rocker arm; the rotating shaft is rotatably connected to the rocker arm.

[0023] According to the coaxiality measuring machine of the workpiece to be tested, it also includes an alarm module, which receives each of the data signals of the measuring module, performs calculations based on each of the data signals, and determines whether the coaxiality of the workpiece to be tested is qualified based on the calculation results. If it is unqualified, the alarm module will alarm.

[0024] According to the coaxiality measuring machine for the workpiece to be tested, the driving module also includes a control electrical box and a motor protection cover; the control electrical box is electrically connected to the driving motor and is used to control the start and stop of the driving motor; the control electrical box includes a self-locking circuit formed by a circuit breaker, a contactor, a start button and a stop button; the motor protection cover is arranged at the output end of the driving motor.

[0025] According to the coaxiality measuring machine of the workpiece to be tested, the measuring module includes a measuring probe and a displacement sensor, the measuring probe is used to contact the workpiece to be tested and generate a displacement, the displacement sensor converts the displacement into a data signal, and sends the data signal to the display module;

[0026] The end of the measuring probe that is used to contact the object to be measured is cylindrical or conical.

[0027] According to the coaxiality measuring machine for the workpiece to be tested, the workpiece to be tested is a pull rod of an electromagnetic switch.

[0028] In an embodiment of the utility model, a coaxiality measuring machine for a workpiece to be tested is provided, which at least includes a driving module, a transmission module, a measuring module and a display module. The driving module includes a driving motor, which plays a conversion role, converting electrical energy into mechanical energy, and generating a rotating magnetic field through an electric coil to act on the output shaft, the output shaft rotates, and the output shaft is transmitted to the transmission module. The transmission module includes at least one set of rotors, each set of rotors includes two rotors, the workpiece to be tested is placed between the two rotors, and then the transmission module is transmitted to the workpiece to be tested. The workpiece to be tested can be rotated 360 degrees to facilitate the measurement of coaxiality. The measuring module contacts the workpiece to be tested, and the workpiece to be tested generates a displacement to the measuring module during the rotation process. The display module displays the displacement generated by the detection points on the circumference of the workpiece to be tested to the measuring module in a numerical form. By this, the coaxiality measuring machine of the utility model can realize data visualization and improve measurement efficiency and accuracy. Make data visualization. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a front view of the pull rod provided by the prior art;

[0030] Figure 2 It is a top view of a pull rod provided by the prior art;

[0031] Figure 3 This is a front view of a workpiece to be tested provided by an embodiment of the utility model placed on a coaxiality measuring machine, and the dotted line portion in the figure is a perspective view of the corresponding components;

[0032] Figure 4 It is a top view of a workpiece to be tested provided by an embodiment of the utility model placed on a coaxiality measuring machine, and the dotted line portion in the figure is a perspective view of the corresponding components;

[0033] Figure 5 It is a schematic diagram of the exploded structure of a support module provided by an embodiment of the utility model;

[0034] Figure 6 It is a circuit connection diagram of a control electric box and a drive motor provided in one embodiment of the utility model. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0036] It should also be pointed out that the terms used in the present invention, such as “upper”, “lower”, “left”, “right”, “front”, “back”, “top”, “bottom”, “vertical”, “horizontal”, etc., to indicate directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present invention.

[0037] See also Figure 3-4 In one embodiment of the present invention, a coaxiality measuring machine 100 for a workpiece 200 is provided, comprising:

[0038] A driving module 10, comprising a driving motor 11;

[0039] The transmission module includes at least one set of rotors, each set of rotors includes two rotors 21, which are used to drive the test piece 200 to rotate; the axes of the two rotors 21 in each set are arranged in parallel, and the radial spacing between the two rotors 21 is smaller than the radial width of the test piece 200; the driving motor 11 is transmission-connected to the rotors 21;

[0040] The measuring module 30 is used to measure the displacements of different points on the circumference of the test piece 200 caused by the measuring module 30, and convert the displacements into data signals and send them to the display module 40;

[0041] The display module 40 receives each data signal and converts each data signal into a numerical value for display.

[0042] In this embodiment, when the coaxiality measuring machine 100 is used to perform coaxiality detection on the workpiece 200 to be tested, the workpiece 200 to be tested is first placed on the transmission module, and the workpiece 200 to be tested can be selected as the pull rod of the electromagnetic switch. The two rotors 21 on the transmission module can support the workpiece 200 to be tested. The workpiece 200 placed on the rotor 21 is in contact with the measuring module 30, and then the driving motor 11 is started, and the driving motor 11 is transmitted to at least one rotor 21, and the rotor 21 that obtains kinetic energy rotates, and then the rotor 21 drives the workpiece 200 to rotate. The measuring module 30 has an elastic member, and contacts the workpiece 200 to be tested through the elastic member, so that the workpiece 200 to be tested always fits with it during rotation, so that the measuring module 30 may generate displacement in the process of fitting with the rotating workpiece 200, that is, the measuring module 30 can measure the displacement of the workpiece 200 to it at different points in the circumference. The measuring module 30 is electrically connected to the display module 40. The measuring module 30 converts the displacement into a data signal and sends it to the display module 40. That is, the data signal is easy to transmit and carries the information of the displacement. The data signal can be a voltage signal or a current signal that can carry the displacement information. The display module 40 displays the displacement in a numerical value. The display module 40 can be a numerical display, and a liquid crystal LED display can be used for display, so that the data is displayed intuitively, reducing manual misreading and improving the detection accuracy and efficiency of coaxiality. Optionally, the measuring module and the display module can be a digital display dial indicator that is integrated.

[0043] See also Figure 3-4 As an optional embodiment, the test piece 200 is provided with a plurality of round rods along the axial direction;

[0044] The transmission module is provided with at least two groups of rotors 21, the position of each group of rotors 21 corresponds to the position of different round rods, and the height difference between the top surfaces of the two groups of rotors 21 is equal to the height difference between the bottom surfaces of the corresponding round rods.

[0045] In this embodiment, in order to stably support the test piece 200, multiple groups of rotors 21 may be provided. If there is a height difference between the round bars of the test piece 200, that is, the diameters of the round bars are different, in order to set the top surface of the rotor 21 supporting the corresponding round bar of the test piece 200 to fit with the bottom surface of the round bar, the height difference between the top surfaces of the two groups of rotors 21 and the height difference between the bottom surfaces of the corresponding round bars are set to be equal. If the part supported by the rotor 21 is a flat structure of the test piece 200, the rotor 21 supporting the flat structure is set so that during the rotation of the flat structure, the rotor 21 is tangent to the two side surfaces of the flat structure in the radial direction.

[0046] See also Figure 3As an optional embodiment, the transmission module also includes two first gears 22 and a second gear (not shown in the figure), the second gear is meshed between the two first gears 22; the second gear is transmission connected to the output shaft of the drive motor 11; the two first gears 22 are transmission connected to the two rotors 21 through the connecting shaft 23 respectively; the two corresponding rotors 21 between the two groups are transmission connected through the connecting shaft 23.

[0047] In this embodiment, the two first gears 22 are respectively meshed with the second gear, so that the two first gears 22 rotate in the same direction, thereby driving each rotor 21 to rotate in the same direction. Two corresponding rotors in different groups (i.e., two rotors on the same axis) are connected by a connecting shaft 23. Each first gear 22 can also be fixed by two fixed gears, which are mounted on the mounting frame 53, and the first gear 22 is meshed between the two fixed gears. Each gear can be made of domestic Fengli gears, which have high transmission accuracy, compact structure, high wear resistance and long life.

[0048] See also Figure 5 As an optional embodiment, the coaxiality measuring machine 100 also includes a supporting module 50, which includes a raised frame 51, a fixed plate 52 and a mounting frame 53 for mounting the parts to be mounted, the fixed plate 52 is arranged on the top surface of the raised frame 51, and the mounting frame 53 is arranged on the raised frame 51 or the fixed plate 52; the mounting frame 53 is provided with a plurality of bosses 531 and grooves 532 respectively adapted to each of the parts to be mounted.

[0049] The drive motor 11 is mounted on the mounting frame 53. The drive motor 11 is located on the left side of the mounting frame 53, and the output shaft of the drive motor 11 is arranged toward the right side of the mounting frame 53.

[0050] The rotor 21 is mounted on the mounting frame 53 , and the rotor 21 is located on the right side of the driving motor 11 ;

[0051] The measuring module 30 is disposed on the fixing plate 52 or the mounting frame 53;

[0052] The display module 40 is disposed on the fixing plate 52 or the mounting frame 53 .

[0053] In this embodiment, the raising frame 51 is used to raise the components installed on the supporting module 50 to a height that is convenient for the user to operate; the fixing plate 52 is used to install the components; the mounting frame 53 is provided with a boss 531 and a groove 532, and the height of the boss 531 and the depth of the groove 532 are set according to the components installed thereon.

[0054] See also Figure 3As an optional embodiment, the coaxiality measuring machine 100 also includes a first limit member for limiting the axial movement of the workpiece 200 to be measured, and the first limit member is installed on the mounting frame 53; the first limit member is a screw assembly 60, and the screw assembly 60 includes a screw 61 and a nut 62, and the screw 61 is fixed to the mounting frame 53 by the nut 62.

[0055] In this embodiment, in order to prevent the piece to be tested 200 from moving in the axial direction and affecting the measurement result, a first limit member is correspondingly provided, and multiple first limit members may be provided optionally. After the piece to be tested 200 is placed in the transmission module, the first limit member is abutted against the end face of the piece to be tested 200 in the axial direction. The first limit member may be optionally a screw assembly 60, and the screw 61 may be moved so that its end face in the axial direction abuts against the end face of the piece to be tested 200. Of course, the first limit member may also be provided as a limit block (not shown), and the space occupied by the limit block is relatively small. Optionally, limit blocks and screw assemblies 60 are provided at both ends of the piece to be tested 200 in the axial direction, respectively. Since the screw 61 can be moved, the distance between the two limit members can be adjusted to facilitate the placement of the piece to be tested 200.

[0056] As an optional embodiment, the coaxiality measuring machine 100 also includes a rocker arm assembly, which includes a rocker arm 81, a rocker arm base 82, a rotating shaft 83 and a hydraulic cylinder 84; the rocker arm 81 is movably mounted on the rocker arm base 82; the hydraulic cylinder 84 is transmission-connected to the rocker arm 81; and the rotating shaft 83 is rotatably connected to the rocker arm 81.

[0057] In this embodiment, the rotating shaft 83 on the rocker arm assembly can be attached to the upper part of the test piece 200 or away from the test piece 200 under the drive of the rocker arm 81. When it is attached to the upper part of the test piece 200, it can limit the upward displacement of the test piece 200 during rotation, so that the measurement result is more accurate. The hydraulic cylinder 84 mainly uses pressure to push the internal piston to move axially, so that the hydraulic cylinder 84 can drive the rocker arm 81 to move up and down repeatedly according to a predetermined stroke. An axle pin is provided in the middle of the hydraulic cylinder 84, and the axle pin is fixedly connected to the rocker arm 81. When the hydraulic cylinder 84 is pushed by pressure, the piston pushes the axle pin upward, and the rocker arm 81 also moves upward. At this time, it is in a loosened state, that is, the rotating shaft 83 moves upward with the rocker arm 81 to separate from the workpiece 200 to be tested; similarly, when the axle pin of the hydraulic cylinder 84 is pulled downward, the rocker arm 81 also moves downward. At this time, it is in a working state, that is, the rotating shaft 83 moves downward with the rocker arm 81 until it fits with the workpiece 200 to be tested.

[0058] See also Figure 3-4As an optional embodiment, the coaxiality measuring machine 100 also includes an alarm module 70. The alarm module 70 of the coaxiality measuring machine 100 receives various data signals from the measuring module 30, and performs calculations based on the various data signals. It determines whether the coaxiality of the test piece 200 is qualified based on the calculation results. If it is unqualified, the alarm module 70 will alarm.

[0059] In this embodiment, the alarm module 70 includes an indicator light and / or a buzzer. For example, when the coaxiality is qualified, the indicator light turns green, and if the coaxiality is unqualified, the indicator light turns red and the buzzer sounds.

[0060] See also Figure 3-4 As an optional embodiment, the drive module 10 further includes a control box 12 and a motor protection shell 13; the control box 12 is electrically connected to the drive motor 11 and is used to control the start and stop of the drive motor 11; the control box 12 includes a self-locking circuit formed by a circuit breaker 121, a contactor 122, a start button 123 and a stop button 124 (see Figure 6 ); The motor protection shell 13 is disposed on the output end of the driving motor 11.

[0061] In this embodiment, the motor protection shell 13 plays a protective role and is used to protect the components inside it. The start and stop of the drive motor 11 are controlled by the control box 12. Although the circuit breaker 121 can also directly control the drive motor 11, in order to improve the safety of the drive motor 11, the circuit breaker 121 is used together with the contactor 122.

[0062] See also Figure 3-4 As an optional embodiment, the measuring module 30 includes a measuring probe 31 and a displacement sensor 32. The measuring probe 31 is used to contact the test piece 200 and generate a displacement. The displacement sensor 32 converts the displacement into a data signal and sends the data signal to the display module 40.

[0063] One end of the measuring probe 31 that is in contact with the object to be measured 200 is cylindrical or conical.

[0064] In this embodiment, the measuring probe 31 may be optionally provided with an elastic member, and the measuring probe 31 is attached to the test piece 200. During the rotation of the test piece 200, the measuring probe 31 may generate corresponding displacement, and the displacement sensor 32 may be a sensor of the Keyence brand. The displacement sensor 32 may convert the displacement generated by the measuring probe 31 into a current signal or voltage signal recording information of the displacement (the displacement sensor may be provided with a capacitor, and the dielectric constant of the capacitor may be changed when the measuring probe 31 generates displacement, and then converted into a current signal or voltage signal recording information of the displacement through an external circuit connected to the capacitor), and send it to the display module 40, and the display module 40 calculates the corresponding value according to the current signal or voltage signal and displays it. The end of the measuring probe 31 used to contact the test piece 200 is cylindrical or conical, and setting it to a conical shape can improve the measurement accuracy.

[0065] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field can make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A coaxiality measuring machine for a workpiece to be tested, characterized in that: include: A drive module, including a drive motor; The transmission module comprises at least one group of rotors, each group of rotors comprises two rotors, and is used to drive the test piece to rotate; the axes of the two rotors in each group are arranged in parallel, and the radial spacing between the two rotors is less than or equal to the radial width of the test piece; the driving motor is in transmission connection with the rotors; A measuring module, used for measuring the displacements of different points on the circumference of the workpiece to be tested, and converting the displacements into data signals to send to a display module; The display module is used to receive each of the data signals and convert each of the data signals into a numerical value for display.

2. The coaxiality measuring machine for the workpiece to be measured according to claim 1, characterized in that: The test piece is provided with a plurality of round rods along the axial direction; The transmission module is provided with at least two groups of rotors, the position of each group of rotors corresponds to the position of different round rods, and the height difference between the top surfaces of the two groups of rotors is equal to the height difference between the bottom surfaces of the corresponding round rods.

3. The coaxiality measuring machine for a workpiece to be measured according to claim 1, characterized in that: The transmission module also includes two first gears and a second gear, the second gear is meshed between the two first gears; the second gear is transmission connected to the output shaft of the drive motor; the two first gears are transmission connected to the two rotors through a connecting shaft respectively; the two corresponding rotors between the two groups are transmission connected through a connecting shaft.

4. The coaxiality measuring machine for a workpiece to be measured according to claim 1, characterized in that: It also includes a support module, which includes a support frame, a fixing plate and a mounting frame for mounting the parts to be mounted, the fixing plate is arranged on the top surface of the support frame, and the mounting frame is arranged on the support frame or the fixing plate; the mounting frame is provided with a plurality of bosses and grooves respectively matched with the parts to be mounted; The drive motor is installed on the mounting frame, the drive motor is located on the left side of the mounting frame, and the output shaft of the drive motor is arranged toward the right side of the mounting frame; The rotor is mounted on the mounting frame, and the rotor is located on the right side of the driving motor; The measuring module is arranged on the fixing plate or the mounting frame; The display module is arranged on the fixing plate or the mounting frame.

5. The coaxiality measuring machine for a workpiece to be measured according to claim 4, characterized in that: It also includes a first limiter for limiting the axial movement of the test piece, and the first limiter is installed on the mounting frame; the first limiter is a screw assembly, and the screw assembly includes a screw and a nut, and the screw is fixed to the mounting frame through the nut.

6. The coaxiality measuring machine for a workpiece to be measured according to claim 1, characterized in that: It also includes a rocker arm assembly, which includes a rocker arm, a rocker arm base, a rotating shaft and a hydraulic cylinder; the rocker arm is movably mounted on the rocker arm base; the hydraulic cylinder is transmission-connected to the rocker arm; and the rotating shaft is rotatably connected to the rocker arm.

7. The coaxiality measuring machine for a workpiece to be measured according to claim 1, characterized in that: It also includes an alarm module, which receives each of the data signals from the measuring module, performs calculations based on each of the data signals, and determines whether the coaxiality of the test piece is qualified based on the calculation results. If it is unqualified, the alarm module will sound an alarm.

8. The coaxiality measuring machine for a workpiece to be measured according to claim 1, characterized in that: The drive module also includes a control electrical box and a motor protection shell; the control electrical box is electrically connected to the drive motor and is used to control the start and stop of the drive motor; the control electrical box includes a self-locking circuit formed by a circuit breaker, a contactor, a start button and a stop button; the motor protection shell is provided at the output end of the drive motor.

9. The coaxiality measuring machine for a workpiece to be measured according to claim 1, characterized in that: The measuring module includes a measuring probe and a displacement sensor, wherein the measuring probe is used to contact the test piece and generate a displacement, and the displacement sensor converts the displacement into a data signal and sends the data signal to the display module; The end of the measuring probe that is used to contact the object to be measured is cylindrical or conical.

10. The coaxiality measuring machine for a workpiece to be measured according to claim 1, characterized in that: The part to be tested is a pull rod of an electromagnetic switch.

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