Encoder correction device and encoder manufacturing method
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- MITSUBISHI ELECTRIC CORP
- Filing Date
- 2026-01-19
- Publication Date
- 2026-07-30
Smart Images
Figure JP2026001399_30072026_PF_FP_ABST
Abstract
Description
Encoder correction device and method for manufacturing an encoder
[0001] The present disclosure relates to an encoder correction device that corrects a test encoder for detecting the position of a test motor and a method for manufacturing an encoder.
[0002] Conventionally, a technique for correcting a test encoder that detects the position of a test motor has been known. For example, Patent Document 1 discloses an encoder correction device provided with a reference encoder having a higher detection accuracy than the test encoder. In the encoder correction device disclosed in Patent Document 1, the reference encoder and the test motor are connected by a manual coupling, and correction data is generated based on the difference in position data detected by both encoders when the test motor is driven. By correcting the position data of the test encoder using this correction data, it is possible to reduce the detection error caused by the machining accuracy of the parts and the irregularity of the assembly error of the parts.
[0003] Japanese Patent Laid-Open No. 4-194615
[0004] In the technique disclosed in Patent Document 1, since a manual coupling is used for connecting the reference encoder and the test motor, each time the test motor is attached to the encoder correction device, if the test motor is attached to and detached from the manual coupling, there is a possibility of connection errors by the operator. Further, in the technique disclosed in Patent Document 1, since both encoders are installed such that the central axis of the reference encoder and the central axis of the test encoder are horizontally positioned, due to the influence of gravity, there is a possibility that the reference encoder and the test encoder are attached to the encoder correction device in a state inclined with respect to the horizontal direction. Due to these factors, eccentricity and angular deviation are likely to occur between the reference encoder, the test encoder, and the test motor when they are attached to the encoder correction device. As a result, there is a problem that the coaxiality between the two encoders deteriorates and the accuracy of correcting the position data of the test encoder deteriorates.
[0005] The present disclosure has been made in view of the above, and an object thereof is to obtain an encoder correction device capable of suppressing deterioration in the accuracy of correcting the position data of a test encoder.
[0006] To solve the above-mentioned problems and achieve the objective, the encoder correction device according to this disclosure is an encoder correction device for correcting an encoder under test that detects the position of a motor under test, and comprises a reference encoder, a drive motor, an encoder under test, a motor under test, a coupling mechanism, an eccentricity absorption mechanism, and an angle deflection absorption mechanism. The drive motor is attached to the reference encoder. The encoder under test is positioned away from the reference encoder and the drive motor in the axial direction of the drive motor. The motor under test is attached to the encoder under test. The coupling mechanism connects the drive motor and the motor under test and has a gripping portion that grips the motor shaft of the motor under test. The eccentricity absorption mechanism supports the encoder under test and the motor under test so that they can move along the vertical direction, which is perpendicular to the axial direction of the drive motor. The angle deflection absorption mechanism adjusts the motor shaft of the motor under test and the central axis of the gripping portion of the coupling mechanism to be parallel.
[0007] The encoder correction device described herein has the effect of suppressing the deterioration of accuracy in correcting the position data of the encoder under test.
[0008] An explanatory diagram showing the configuration of the encoder correction device according to Embodiment 1. A cross-sectional view showing the configuration of the encoder correction device according to Embodiment 1. A cross-sectional view showing the assembly procedure of the angle deviation absorption mechanism of the encoder correction device according to Embodiment 1. A cross-sectional view showing the assembly procedure of the angle deviation absorption mechanism of the encoder correction device according to Embodiment 1. A cross-sectional view showing the assembly procedure of the angle deviation absorption mechanism of the encoder correction device according to Embodiment 1. A cross-sectional view showing the assembly procedure of the angle deviation absorption mechanism of the encoder correction device according to Embodiment 1. A partially enlarged view showing the state in which the motor shaft of the motor under test is gripped by the gripping claw of the coupling mechanism in an encoder correction device without an eccentricity absorption mechanism and an angle deviation absorption mechanism. A cross-sectional view showing the configuration of the encoder correction device according to Embodiment 2. A cross-sectional view showing the configuration of the encoder correction device according to Embodiment 3. A cross-sectional view showing the configuration of the encoder correction device according to Embodiment 4, showing the state in which the second jig has moved to a position that supports the motor under test. A cross-sectional view showing the configuration of the encoder correction device according to Embodiment 4, showing the state in which the second jig has moved to a position away from the motor under test. A flowchart showing an example of the positioning work process for the motor under test in the encoder correction device according to Embodiment 4.
[0009] The encoder correction device and the method for manufacturing the encoder according to the embodiment will be described in detail below with reference to the drawings.
[0010] Embodiment 1. Figure 1 is an explanatory diagram showing the configuration of the encoder correction device 100 according to Embodiment 1. Figure 2 is a cross-sectional view showing the configuration of the encoder correction device 100 according to Embodiment 1. As shown in Figure 1, the encoder correction device 100 includes a reference encoder 1, a drive motor 2, an encoder under test 3, a signal processing circuit 9, a PC (Personal Computer) 10, and a drive device 15. Also, as shown in Figure 2, the encoder correction device 100 includes a motor under test 4, a frame 5, a coupling mechanism 6, an eccentricity absorption mechanism 7, and an angle deflection absorption mechanism 8. The encoder correction device 100 is a device that corrects the encoder under test 3, which detects the position of the motor under test 4.
[0011] First, with reference to Figure 1, the correction process of the encoder under test 3 using the encoder correction device 100 will be explained. The encoder correction device 100 generates correction data based on the difference in position data detected by the reference encoder 1 and the encoder under test 3 when the drive motor 2 is driven. The reference encoder 1 and the encoder under test 3 each have a built-in signal processing unit (not shown). When correcting the encoder under test 3, the drive motor 2 attached to the reference encoder 1 and the motor under test 4 attached to the encoder under test 3 are connected, and the drive motor 2 is driven using the drive device 15. At that time, the position data (counter value) of the reference encoder 1 and the position data (counter value) of the encoder under test 3 are sampled synchronously by the signal processing circuit 9.
[0012] The signal processing circuit 9 acquires position data from both the reference encoder 1 and the encoder under test 3 via serial communication. The signal processing circuit 9 has both the function of buffering both position data in the SRAM (Static Random Access Memory) area 9a and the function of transmitting both buffered position data to the PC 10. The PC 10 performs calculations based on both acquired position data. That is, the PC 10 generates correction data based on the difference between both acquired position data. The PC 10 uses the correction data to correct the position data of the encoder under test 3 via the signal processing circuit 9.
[0013] Next, with reference to Figure 2, each component of the encoder correction device 100 will be described. When describing the direction of each component of the encoder correction device 100 below, the direction parallel to the central axis AX of the drive motor 2 will be called the axial direction, the direction perpendicular to the central axis AX will be called the vertical direction, and the rotational direction about the central axis AX will be called the circumferential direction. The axial direction coincides with the vertical direction of the paper in Figures 2 to 9. In the following description, the upper side of the paper in Figures 2 to 9 will be considered one of the axial directions, and the lower side of the paper in Figures 2 to 9 will be considered the other axial direction. Also, the direction toward the central axis AX in the vertical direction will be considered the inside, and the opposite direction will be considered the outside. In this embodiment, the case in which the axial direction coincides with the vertical direction and the vertical direction coincides with the horizontal direction will be described as an example, but this is not intended to limit the orientation in which the encoder correction device 100 is used. In this embodiment, one of the axial directions is upward, and the other of the axial directions is downward.
[0014] The frame 5 is a member that supports each component of the encoder correction device 100. The frame 5 has a plurality of support columns 5a, a base 5b, and a mounting portion 5c. Each support column 5a extends along the axial direction. The base 5b extends along the vertical direction. The shape of the base 5b is flat. The base 5b is installed straddling each support column 5a. A through hole 5e is formed in the vertical center of the base 5b for inserting a part of the rotary chuck 6b, which will be described later. The through hole 5e penetrates from one end face to the other end face of the base 5b in the axial direction.
[0015] The mounting portion 5c is the part to which the drive motor 2 is fixed. The mounting portion 5c protrudes axially from the other end face of the base 5b in the axial direction, around the portion where the through hole 5e is opened. The shape of the mounting portion 5c is cylindrical. At the tip of the mounting portion 5c, a reduced-diameter portion 5d is formed, which is the most narrowed part of the mounting portion 5c.
[0016] The drive motor 2 is a device attached to the reference encoder 1. The drive motor 2 is fixed to the frame 5. Specifically, the housing of the drive motor 2 is fixed to the tip of the reduced diameter portion 5d. The drive motor 2 has a motor shaft 2a that extends along the axial direction. The motor shaft 2a protrudes from the housing of the drive motor 2 toward the coupling mechanism 6 in one axial direction. The motor shaft 2a is inserted from the reduced diameter portion 5d into the inner circumference of the mounting portion 5c.
[0017] The reference encoder 1 is a device with higher detection accuracy than the encoder 3 under test. The reference encoder 1 is attached to the other end of the housing of the drive motor 2 in the axial direction. The reference encoder 1 is fixed to the frame 5 via the drive motor 2.
[0018] The encoder 3 under test is a device positioned away from the reference encoder 1 and the drive motor 2 in the axial direction of the drive motor 2.
[0019] The motor under test 4 is a device attached to the encoder under test 3. The motor under test 4 is attached to the other end of the encoder under test 3 in the axial direction. The motor under test 4 has a motor shaft 4a that extends along the axial direction. The motor shaft 4a protrudes in the other axial direction from the housing of the motor under test 4 toward the coupling mechanism 6.
[0020] The coupling mechanism 6 is a mechanism that connects the drive motor 2 and the motor under test 4. The coupling mechanism 6 has a coupling 6a, a rotary chuck 6b, and a plurality of gripping jaws 6c. The coupling 6a is located on one side of the drive motor 2 in the axial direction. The coupling 6a connects the motor shaft 2a of the drive motor 2 to the rotary chuck 6b. The coupling 6a is located on the inner circumference of the mounting portion 5c.
[0021] The rotary chuck 6b is a drive component that allows each of the multiple gripping jaws 6c to move closer to and further away from the motor shaft 4a in the vertical direction. The configuration of the rotary chuck 6b is not particularly limited as long as it can drive the multiple gripping jaws 6c. The rotary chuck 6b may be, for example, an air chuck operated by air, or an electric chuck operated by a motor. The rotary chuck 6b is positioned on one side of the coupling 6a in the axial direction. The rotary chuck 6b protrudes from the inner circumference of the mounting portion 5c through the through hole 5e in one axial direction from the base 5b. The rotary chuck 6b is fixed on the base 5b.
[0022] The gripping claws 6c, which are the gripping parts, are components for gripping the motor shaft 4a of the motor under test 4. In this embodiment, the gripping claws 6c automatically grip the motor shaft 4a of the motor under test 4 using a rotary chuck 6b. In the example shown in Figure 2, each of the multiple gripping claws 6c approaches the motor shaft 4a in the vertical direction, thereby gripping the motor shaft 4a by sandwiching it between the multiple gripping claws 6c. The multiple gripping claws 6c are arranged at equal intervals in the circumferential direction. In this specification, the inner diameter of the virtual circle formed by connecting the multiple gripping claws 6c is defined as the inner diameter of the gripping claws 6c, and the central axis of the virtual circle is defined as the central axis of the gripping claws 6c. The drive motor 2 and the motor under test 4 are connected to each other via a coupling 6a, a rotary chuck 6b, and gripping claws 6c. If the rotary chuck 6b is an air chuck, the connection between the reference encoder 1 and the motor under test 4 is performed automatically by supplying and discharging air.
[0023] The eccentricity absorption mechanism 7 is a mechanism that supports the encoder 3 and motor 4 under test so that they can move along the vertical direction, which is perpendicular to the axial direction of the drive motor 2. The eccentricity absorption mechanism 7 is located between the base 5b and the angle deflection absorption mechanism 8 in the axial direction. The eccentricity absorption mechanism 7 is located around the rotary chuck 6b. The eccentricity absorption mechanism 7 is an XY linear guide (orthogonal linear guide) having a first rail 7a, a second rail 7b, and a slider 7c.
[0024] The first rail 7a extends linearly along one of the vertical directions. The second rail 7b is attached to the first rail 7a so as to be relatively movable and extends linearly in a direction perpendicular to the extension direction of the first rail 7a. The second rail 7b is movable along the extension direction of the first rail 7a. The slider 7c is attached to the second rail 7b so as to be relatively movable and is attached to the motor under test 4 via the angle deflection absorption mechanism 8. The slider 7c is movable along the extension direction of the second rail 7b.
[0025] The first rail 7a is fixed on the base 5b, and the slider 7c is fixed to the first jig 8a of the angle deflection absorption mechanism 8 (described later), which allows the encoder 3 and motor 4 under test to move along the vertical direction. In other words, the encoder 3 and motor 4 under test can move in a plane perpendicular to the axial direction of the drive motor 2. Specifically, by moving the second rail 7b relative to the extension direction of the first rail 7a, the slider 7c, the angle deflection absorption mechanism 8, the encoder 3 and motor 4 under test move along the extension direction of the first rail 7a in the vertical direction. On the other hand, by moving the slider 7c relative to the extension direction of the second rail 7b, the angle deflection absorption mechanism 8, the encoder 3 and motor 4 under test move along the extension direction of the second rail 7b in the vertical direction.
[0026] The angle deflection absorption mechanism 8 is a mechanism that adjusts the central axis of the motor shaft 4a of the motor under test 4 and the central axis of the plurality of gripping claws 6c of the connecting mechanism 6 to be parallel. In this embodiment, the angle deflection absorption mechanism 8 can adjust the inclination angle of the motor shaft 4a of the motor under test 4 with respect to the axial direction. The angle deflection absorption mechanism 8 includes a first jig 8a, a second jig 8b, a plurality of elastic members 8c, a plurality of bolts 8d, a plurality of nuts 8e, and a plurality of set screws 8f.
[0027] The first jig 8a is positioned on the eccentricity absorption mechanism 7. The first jig 8a is fixed to the slider 7c. A positioning hole 8g is formed in the vertical center of the first jig 8a for positioning the motor shaft 4a and gripping claws 6c of the motor under test 4. The positioning hole 8g is cylindrical in shape with a constant diameter along its entire axial length. The first jig 8a has a plurality of through holes 8h for inserting bolts 8d. Each through hole 8h penetrates from one end face to the other end face of the first jig 8a in the axial direction. Each through hole 8h is positioned around the positioning hole 8g. Each through hole 8h is stepped cylindrical in shape, with the diameter increasing from one end to the other in the axial direction. Each through hole 8h includes a small diameter portion into which the bolt 8d is screwed and a large diameter portion into which the tip of the bolt 8d and the nut 8e are positioned.
[0028] The second jig 8b supports the motor 4 under test. The second jig 8b is positioned axially on one side of the first jig 8a, with a gap 11 between them. The second jig 8b is positioned axially on the opposite side of the eccentricity absorption mechanism 7 from the first jig 8a. A mounting hole 8i for positioning the motor 4 under test is formed in the vertical center of the second jig 8b. The mounting hole 8i has a stepped cylindrical shape, with its diameter decreasing from one side to the other in the axial direction. A flat support surface 8k extending vertically is formed on the inner circumferential surface of the mounting hole 8i. The support surface 8k contacts the vertically extending plane 4b of the motor 4 under test, supporting the motor 4 from the other side in the axial direction.
[0029] The second jig 8b has a plurality of through holes 8j for inserting bolts 8d. Each through hole 8j penetrates from one end face to the other end face of the second jig 8b in the axial direction. Each through hole 8j is arranged around the placement hole 8i. The shape of each through hole 8j is a stepped cylindrical shape in which the diameter changes from one end to the other in the axial direction. Each through hole 8j includes a large diameter portion in which the head of the bolt 8d is placed, a small diameter portion through which the shaft portion of the bolt 8d is inserted, and a large diameter portion through which the shaft portion of the bolt 8d is inserted and in which a part of the elastic member 8c is placed. The second jig 8b has a plurality of screw holes 8m for screwing in set screws 8f. Each screw hole 8m penetrates from one end face to the other end face of the second jig 8b in the axial direction. Each screw hole 8m is located outside the through holes 8j. Each screw hole 8m has a stepped cylindrical shape, with the diameter decreasing from one side to the other in the axial direction.
[0030] Each elastic member 8c is positioned axially between the first jig 8a and the second jig 8b, and biases the first jig 8a and the second jig 8b in a direction that separates them from each other by elastic force. As a result, an axial gap 11 is formed between the first jig 8a and the second jig 8b, and the elastic force of the elastic member 8c causes the second jig 8b to float in a tiltable manner relative to the first jig 8a. The motor under test 4 supported by the second jig 8b also floats in a tiltable manner relative to the first jig 8a. Here, "floating" means a state in which the tilt of the second jig 8b and the tilt of the motor under test 4 can be freely changed. In this embodiment, each elastic member 8c is a compression spring that can expand and contract in the axial direction, but it may also be an elastic material such as rubber or sponge.
[0031] Each elastic member 8c is positioned on the outer circumference of the shaft portion of the bolt 8d. In other words, the shaft portion of each bolt 8d is inserted through the inner circumference of the elastic member 8c. A portion of the elastic member 8c is positioned within the insertion hole 8j. One end of the elastic member 8c in the axial direction is in contact with the stepped surface on the inner circumferential surface of the insertion hole 8j. The other end of the elastic member 8c in the axial direction is in contact with one end of the first jig 8a in the axial direction (the end of the first jig 8a facing the second jig 8b). Preferably, the elastic force of each elastic member 8c is greater than the load of the motor under test 4 and less than the gripping force of the gripping claw 6c of the connecting mechanism 6. In this way, the inclination angle of the second jig 8b in the axial direction can be adjusted by the amount of the gap 11.
[0032] Each bolt 8d is a retaining member that connects the first jig 8a and the second jig 8b. Each bolt 8d also plays a role in regulating the height of the gap 11. The shaft of each bolt 8d is inserted through the insertion hole 8j and screwed into the insertion hole 8h. The head of each bolt 8d is in contact with the stepped surface on the inner circumferential surface of the insertion hole 8j. It is preferable that the elastic member 8c and the bolts 8d are arranged at three or more equal intervals on the same circumference centered on the motor shaft 4a of the motor under test 4. It is preferable that the elastic member 8c and the bolts 8d are arranged at the same position on the same circumference centered on the motor shaft 4a of the motor under test 4, as shown in Figure 2, but they may be arranged at different positions.
[0033] Each nut 8e is a component that screws onto the tip of each bolt 8d to fix each bolt 8d in a non-rotatable state. The nut 8e is in contact with the stepped surface on the inner circumferential surface of the through hole 8h.
[0034] Each set screw 8f is a component that temporarily fixes the second jig 8b to the first jig 8a in an immovable manner during the assembly of the angle deflection absorption mechanism 8. Each set screw 8f is positioned near one of the multiple bolts 8d. Each set screw 8f is screwed into a screw hole 8m. The tip of each set screw 8f protrudes from the screw hole 8m toward the first jig 8a and is located within the gap 11. As will be described in detail later, each set screw 8f is capable of contacting and separating from one end of the first jig 8a in the axial direction. By bringing each set screw 8f into contact with one end of the first jig 8a in the axial direction, the second jig 8b can be temporarily fixed to the first jig 8a in an immovable manner. On the other hand, by separating each set screw 8f from one end of the first jig 8a in the axial direction, the second jig 8b can be held in a movable (tiltable) manner on the first jig 8a.
[0035] Next, with reference to Figures 2 to 6, a method for manufacturing an encoder using the encoder correction device 100 according to Embodiment 1 will be described. Figures 3 to 6 are cross-sectional views showing the assembly procedure of the angle deviation absorption mechanism 8 of the encoder correction device 100 according to Embodiment 1. The method for manufacturing an encoder includes an assembly step, a coupling step, and a correction step.
[0036] The assembly process involves assembling the components other than the encoder 3 and motor 4 under test shown in Figure 2. In the assembly process, the reference encoder 1, drive motor 2, coupling mechanism 6, eccentricity absorption mechanism 7, and angle deflection absorption mechanism 8 are installed on the frame 5. Specifically, in the assembly process, the drive motor 2 attached to the reference encoder 1 is fixed to the mounting part 5c of the frame 5. In the assembly process, the coupling 6a of the coupling mechanism 6 is connected to the motor shaft 2a of the drive motor 2, and the rotary chuck 6b of the coupling mechanism 6 is fixed on the base 5b. In the assembly process, the eccentricity absorption mechanism 7 is arranged around the coupling mechanism 6 and fixed on the base 5b. In the assembly process, the angle deflection absorption mechanism 8 is fixed on the slider 7c of the eccentricity absorption mechanism 7.
[0037] Here, the assembly procedure for the angle deflection absorption mechanism 8 will be described. As shown in Figure 3, first, the second jig 8b is installed on the first jig 8a using a plurality of elastic members 8c and a plurality of bolts 8d. Specifically, each bolt 8d is inserted through the insertion hole 8j of the second jig 8b, the inner circumference of the elastic member 8c, and the insertion hole 8h of the first jig 8a. At this time, an axial gap 11 is formed between the first jig 8a and the second jig 8b, and the elastic force of the elastic member 8c causes the second jig 8b to float in a tiltable state relative to the first jig 8a. The position of the second jig 8b is determined by the position of each bolt 8d, so each bolt 8d is tightened so that the axis of the bolt 8d and the axial direction are parallel. In addition, each set screw 8f is inserted through each screw hole 8m of the second jig 8b, but spaced away from one end of the first jig 8a in the axial direction.
[0038] Next, as shown in Figure 4, each set screw 8f is tightened to bring each set screw 8f into contact with one end of the first jig 8a in the axial direction. This temporarily fixes the second jig 8b to the first jig 8a so that it cannot move, and fixes the position of the second jig 8b. At this time, all set screws 8f are tightened with the same torque.
[0039] Next, as shown in Figure 5, each nut 8e is screwed onto the tip of each bolt 8d to fix each bolt 8d in a non-rotatable state. As a result, even when each elastic member 8c is compressed, the axial force of each bolt 8d does not decrease, and changes in the posture of the second jig 8b due to loosening of each bolt 8d can be suppressed.
[0040] Finally, as shown in Figure 6, each set screw 8f is loosened, separating each set screw 8f from one end of the first jig 8a in the axial direction. This releases the fixation of the position of the second jig 8b. By assembling the angle-shifting absorption mechanism 8 in the above procedure, each nut 8e can be attached to each bolt 8d while maintaining high precision in the horizontality of the second jig 8b.
[0041] The coupling process involves connecting the drive motor 2 and the motor under test 4 using the coupling mechanism 6 shown in Figure 2. Specifically, in the coupling process, the motor under test 4, which is attached to the encoder under test 3, is placed in the placement hole 8i of the second jig 8b, and the motor shaft 4a of the motor under test 4 is gripped by the multiple gripping claws 6c of the coupling mechanism 6. This connects the drive motor 2 and the motor under test 4 via the coupling mechanism 6. At this time, the support surface 8k of the placement hole 8i contacts the plane 4b of the motor under test 4, and the motor under test 4 is supported by the second jig 8b. In the coupling process, the eccentricity absorption mechanism 7 moves the encoder under test 3 and the motor under test 4 along the vertical direction, and the angle deviation absorption mechanism 8 adjusts the motor shaft 4a of the motor under test 4 and the central axis of the gripping claws 6c of the coupling mechanism 6 to be parallel. Specifically, the angle deflection absorption mechanism 8 adjusts the angle of inclination of the motor shaft 4a of the motor under test 4 in the axial direction by changing the inclination angle of the second jig 8b with respect to the axial direction, thereby adjusting the motor shaft 4a of the motor under test 4 and the central axis of the gripping claw 6c of the connecting mechanism 6 to be parallel.
[0042] The correction process involves correcting the encoder under test 3, which detects the position of the motor under test 4, using the encoder correction device 100. Specifically, in the correction process, correction data is generated based on the difference in position data detected by the reference encoder 1 and the encoder under test 3 when the motor under test 4 is driven, and the position data of the encoder under test 3 is corrected using the correction data. The details of the correction process are as described above and are therefore omitted here. By performing the above steps, an encoder with the corrected encoder under test 3 is manufactured.
[0043] Next, the effects of Embodiment 1 will be described.
[0044] FIG. 7 is a partially enlarged view showing a state in which the motor shaft 4a of the test motor 4 is gripped by the gripping claws 6c of the connecting mechanism 6 in the encoder correction device 100C that does not include the eccentric absorption mechanism 7 and the declination absorption mechanism 8. In FIG. 7, the central axis 6d of the gripping claws 6c is illustrated. Due to inevitable geometric tolerances, assembly errors, etc., an eccentricity occurs in which the motor shaft 4a is displaced in the vertical direction with respect to the central axis 6d of the gripping claws 6c, or a declination occurs in which the motor shaft 4a is inclined with respect to the central axis 6d of the gripping claws 6c as shown in FIG. 7. Particularly, in the latter case, the inner diameter R1 of the gripping claws 6c in the closed state is larger than the outer diameter R2 of the motor shaft 4a, and the motor shaft 4a makes a point contact with the gripping claws 6c at point P. When the drive motor 2 (see FIG. 2) rotates once in this state, the motor shaft 4a makes a rolling motion with point P as the rolling point, and the motor shaft 4a having an outer diameter R2 smaller than the inner diameter R1 of the gripping claws 6c in the closed state rotates more than once. Thus, since the rotation amount of the motor shaft 2a (see FIG. 2) of the drive motor 2 connected to the connecting mechanism 6 does not match the rotation amount of the motor shaft 4a of the test motor 4, the accuracy of correcting the position data of the test encoder 3 deteriorates.
[0045] In contrast, in this embodiment, as shown in Figure 2, the encoder correction device 100 includes an eccentricity absorption mechanism 7 that supports the encoder 3 and motor 4 under test so as to be movable along the vertical direction, which is perpendicular to the axial direction of the drive motor 2. The encoder correction device 100 also includes an angle deviation absorption mechanism 8 that adjusts the motor shaft 4a of the motor under test 4 and the central axis 6d of the gripping claw 6c of the coupling mechanism 6 to be parallel. With these configurations, when the motor under test 4 is connected to the drive motor 2 via the coupling mechanism 6, the eccentricity absorption mechanism 7 and the angle deviation absorption mechanism 8 automatically adjust the misalignment (eccentricity and angle deviation) between the motor shaft 4a and the central axis of the gripping claw 6c. As a result, the central axes of the motor shaft 4a and the gripping claw 6c are arranged coaxially, so the motor shaft 4a and the gripping claw 6c make surface contact, preventing the motor shaft 4a from rolling. Therefore, the amount of rotation of the motor shaft 2a of the drive motor 2 connected to the coupling mechanism 6 matches the amount of rotation of the motor shaft 4a of the motor under test 4, which improves the accuracy of correcting the position data of the encoder 3 under test.
[0046] In this embodiment, as shown in Figure 2, the eccentricity absorption mechanism 7 is an XY linear guide having a first rail 7a, a second rail 7b, and a slider 7c. The first rail 7a extends in one direction in the vertical direction. The second rail 7b is attached to the first rail 7a so as to be relatively movable and extends in a direction different from the extension direction of the first rail 7a in the vertical direction. The slider 7c is attached to the second rail 7b so as to be relatively movable and is also attached to the motor under test 4 via an angle deflection absorption mechanism 8, which is another component. With this configuration, the encoder 3 and the motor under test 4 can be smoothly moved along the vertical direction.
[0047] In this embodiment, as shown in FIG. 2, the declination absorption mechanism 8 includes a first jig 8a, a second jig 8b, an elastic member 8c, and a bolt 8d. The second jig 8b is disposed axially on one side of the first jig 8a with a gap 11 left between the first jig 8a and the second jig 8b to support the test motor 4. The elastic member 8c is disposed between the first jig 8a and the second jig 8b and biases the first jig 8a and the second jig 8b in a direction away from each other by an elastic force. The bolt 8d connects the first jig 8a and the second jig 8b. With these configurations, since the second jig 8b is supported by the first jig 8a via the elastic member 8c and the bolt 8d so as to be tiltable, the test encoder 3 and the test motor 4 also tilt as the second jig 8b tilts. Thereby, the tilt angle of the motor shaft 4a of the test encoder 3 and the test motor 4 with respect to the axial direction can be adjusted.
[0048] In this embodiment, as shown in FIG. 2, the elastic member 8c and the bolt 8d are arranged at three or more positions at equal intervals on the same circumference centered on the motor shaft 4a of the test motor 4. With this configuration, since the second jig 8b is supported by the first jig 8a via the elastic member 8c and the bolt 8d so as to be tiltable in a balanced manner, the second jig 8b can be tilted smoothly. Thereby, the tilt angle of the motor shaft 4a of the test encoder 3 and the test motor 4 with respect to the axial direction can be adjusted smoothly.
[0049] In this embodiment, as shown in FIG. 2, the elastic force of the elastic member 8c is greater than the load of the test motor 4 and smaller than the gripping force of the gripping claws 6c of the connecting mechanism 6. With this configuration, the second jig 8b can tilt freely with respect to the first jig 8a by the amount of the gap 11. Thereby, the tilt angle of the motor shaft 4a of the test encoder 3 and the test motor 4 with respect to the axial direction can be adjusted smoothly.
[0050] In this embodiment, as shown in Figure 2, the elastic member 8c and the bolt 8d are positioned at the same location on the same circumference centered on the motor shaft 4a of the motor under test 4. With this configuration, the elastic force acting on the bolt 8d and the reaction force to that elastic force act coaxially, thereby stabilizing the posture of the second jig 8b. Furthermore, with this configuration, the space required for the elastic member 8c and the bolt 8d can be concentrated in the same location, thus saving space.
[0051] In this embodiment, as shown in Figure 2, the angle deflection absorption mechanism 8 has a set screw 8f that temporarily fixes the first jig 8a to the second jig 8b in a way that prevents movement. This configuration allows the orientation of the second jig 8b to be fixed when assembling the angle deflection absorption mechanism 8. This makes it easier to screw a nut 8e onto the tip of a bolt 8d that is inserted through the insertion hole 8j of the second jig 8b and the insertion hole 8h of the first jig 8a, thereby improving the ease of assembly of the encoder correction device 100.
[0052] In this embodiment, the example given is that the axial direction coincides with the vertical direction and the vertical direction coincides with the horizontal direction, but the embodiment is not limited to this. For example, the axial direction may coincide with the horizontal direction and the vertical direction may coincide with the vertical direction. In other words, the central axes of the reference encoder 1, the drive motor 2, the encoder under test 3, and the motor under test 4 may be parallel to the horizontal direction. Even in this configuration, since the encoder correction device 100 is equipped with an eccentricity absorption mechanism 7 and an angle deviation absorption mechanism 8, the occurrence of displacement (eccentricity and angle deviation) between the central axis of the motor shaft 4a and the gripping claw 6c due to the influence of gravity can be suppressed, thereby improving the accuracy of correcting the position data of the encoder under test 3.
[0053] Embodiment 2. Next, an encoder correction device 100A according to Embodiment 2 will be described with reference to Figure 8. Figure 8 is a cross-sectional view showing the configuration of the encoder correction device 100A according to Embodiment 2. In this embodiment, the angular deflection absorption mechanism 8 is a spherical bearing 12, which is different from Embodiment 1 described above. In Embodiment 2, parts that overlap with Embodiment 1 described above are denoted by the same reference numerals and their descriptions are omitted.
[0054] As shown in Figure 8, the angle-shifting absorption mechanism 8 is a spherical bearing 12 having a holder 12a and a ball 12b that slides inside the holder 12a. The spherical bearing 12 can adjust the inclination angle of the motor shaft 4a of the motor under test 4 with respect to the axial direction. By adjusting the inclination angle of the motor shaft 4a of the motor under test 4 with respect to the axial direction, the spherical bearing 12 adjusts the motor shaft 4a of the motor under test 4 and the central axes of the multiple gripping claws 6c of the connecting mechanism 6 to be parallel.
[0055] The holder 12a is positioned on the eccentricity absorption mechanism 7. The holder 12a is fixed to the slider 7c of the eccentricity absorption mechanism 7. A retaining hole 12c for holding the spherical bearing 12 is formed in the vertical center of the holder 12a. The retaining hole 12c penetrates from one end face to the other end face of the holder 12a in the axial direction. The inner circumferential surface of the retaining hole 12c becomes the sliding surface 12d on which the ball 12b slides. The shape of the sliding surface 12d is a spherical band that approaches the central axis AX as it moves from one end to the other in the axial direction.
[0056] The ball 12b supports the motor 4 under test. The motor 4 under test is positioned on the ball 12b. The ball 12b is positioned within the holding hole 12c of the holder 12a and slides along the sliding surface 12d. A mounting hole 12e is formed in the vertical center of the ball 12b for positioning the motor shaft 4a and gripping claws 6c of the motor 4 under test. The mounting hole 12e penetrates from one end face to the other end face of the ball 12b in the axial direction. The shape of the mounting hole 12e is cylindrical with a constant diameter along its entire length in the axial direction. A flat support surface 12f is formed on one end face of the ball 12b in the axial direction. The support surface 12f contacts the vertically extending plane 4b of the motor 4 under test and supports the motor 4 from the other side in the axial direction. As the ball 12b slides along the sliding surface 12d of the holder 12a, the inclination angle of the encoder 3 under test with respect to the axial direction and the inclination angle of the motor shaft 4a of the motor 4 under test with respect to the axial direction can be adjusted to make the motor shaft 4a of the motor 4 under test parallel to the central axis of the gripping claw 6c of the connecting mechanism 6.
[0057] Next, the effects of Embodiment 2 will be described.
[0058] In this embodiment, the angle-shifting absorption mechanism 8 is a spherical bearing 12 having a holder 12a and a ball 12b that slides within the holder 12a. With this configuration, the encoder 3 and the motor 4 under test are supported via the spherical bearing 12 so as to be tiltable with respect to the eccentricity absorption mechanism 7 and the frame 5, so that the tilt angle of the encoder 3 under test in the axial direction and the tilt angle of the motor shaft 4a of the motor 4 under test in the axial direction can be adjusted. That is, when the motor 4 under test is connected to the drive motor 2 via the coupling mechanism 6, the ball 12b slides within the holder 12a, and the tilt angles of the encoder 3 and the motor 4 under test in the axial direction are changed as the ball 12b slides. As a result, the central axis of the motor shaft 4a and the gripping claw 6c are arranged coaxially, so that the motor shaft 4a and the gripping claw 6c make surface contact, preventing rolling motion of the motor shaft 4a. Therefore, the amount of rotation of the motor shaft 2a of the drive motor 2 connected to the coupling mechanism 6 matches the amount of rotation of the motor shaft 4a of the motor under test 4, which improves the accuracy of correcting the position data of the encoder 3 under test.
[0059] Embodiment 3. Next, an encoder correction device 100B according to Embodiment 3 will be described with reference to Figure 9. Figure 9 is a cross-sectional view showing the configuration of the encoder correction device 100B according to Embodiment 3. This embodiment differs from Embodiments 1 and 2 described above in that the bellows coupling 6e, which is part of the coupling mechanism 6, constitutes the angle deflection absorption mechanism 8, and the encoder correction device 100B includes a receiving jig 13 and a pressing mechanism 14. In Embodiment 3, parts that overlap with Embodiments 1 and 2 described above are denoted by the same reference numerals and their description is omitted.
[0060] As shown in Figure 9, the coupling mechanism 6 includes a bellows coupling 6e. The bellows coupling 6e connects the motor shaft 2a of the drive motor 2 to the rotary chuck 6b and is configured to be deformable. The bellows coupling 6e constitutes the angle deflection absorption mechanism 8. The bellows coupling 6e allows adjustment of the inclination angle of the central axes of the rotary chuck 6b and gripping claws 6c with respect to the axial direction. By adjusting the inclination angle of the central axes of the rotary chuck 6b and gripping claws 6c with respect to the axial direction, the bellows coupling 6e adjusts the motor shaft 4a of the motor under test and the central axis of the gripping claws 6c of the coupling mechanism 6 to be parallel.
[0061] In this embodiment, the rotary chuck 6b is positioned away from the frame 5 and is not fixed to the frame 5. The bellows coupling 6e allows the rotary chuck 6b and gripping jaws 6c to float relative to the drive motor 2, allowing them to tilt. Here, "floating" means that the tilt of the rotary chuck 6b and the tilt of the gripping jaws 6c can be freely changed.
[0062] The support jig 13 is positioned on the eccentricity absorption mechanism 7. The support jig 13 is fixed to the slider 7c of the eccentricity absorption mechanism 7. The support jig 13 supports the motor 4 under test. In the vertical center of the support jig 13, there is a mounting hole 13a for positioning a part of the motor 4 under test, including the motor shaft 4a, and the gripping claws 6c. The shape of the mounting hole 13a is a stepped cylindrical shape in which the diameter changes from one end face to the other in the axial direction. The mounting hole 13a penetrates from one end face to the other end face of the support jig 13 in the axial direction. In the axial portion of the inner circumferential surface of the mounting hole 13a, there is a flat support surface 13b that extends vertically. The support surface 13b contacts the vertically extending plane 4b of the motor 4 under test, supporting the motor 4 from the other side in the axial direction. The remainder of the motor 4 under test protrudes from the mounting hole 13a in one axial direction.
[0063] The holding mechanism 14 is a mechanism that holds the encoder 3 and motor 4 under test in place toward the coupling mechanism 6, thereby fixing the posture of the encoder 3 and motor 4 under test. The holding mechanism 14 applies force to the encoder 3 and motor 4 under test in a straight line from one axial direction to the other. The holding mechanism 14 has a support column portion 14a, an arm portion 14b, and a contact portion 14c.
[0064] The support column 14a extends in one axial direction from one end face of the receiving jig 13 in the axial direction. The support column 14a protrudes in one axial direction from the encoder 3 under test. The arm portion 14b extends perpendicularly toward the central axis AX from one end of the support column 14a in the axial direction. The arm portion 14b is positioned on one side of the encoder 3 under test, away from the encoder 3, in the axial direction. The contact portion 14c is provided on the tip of the arm portion 14b that faces the encoder 3 under test. The diameter of the contact portion 14c decreases as it moves from the arm portion 14b toward the encoder 3 under test. The shape of the contact portion 14c is preferably a hemispherical shape with a rounded tip, as shown in Figure 9, but other shapes are also acceptable.
[0065] Next, the effects of Embodiment 3 will be described.
[0066] In this embodiment, the coupling mechanism 6 includes a bellows coupling 6e, which constitutes the angle absorption mechanism 8. With this configuration, the rotary chuck 6b and gripping jaws 6c are supported via the bellows coupling 6e so as to be tiltable relative to the drive motor 2, and the tilt angle of the central axes of the rotary chuck 6b and gripping jaws 6c with respect to the axial direction can be adjusted. That is, when the motor under test 4 is connected to the drive motor 2 via the coupling mechanism 6, the bellows coupling 6e deforms, allowing the central axes of the rotary chuck 6b and gripping jaws 6c to tilt with respect to the axial direction. As a result, the central axes of the motor shaft 4a and the gripping jaws 6c are arranged coaxially, so the motor shaft 4a and the gripping jaws 6c make surface contact, preventing the motor shaft 4a from rolling. Therefore, the amount of rotation of the motor shaft 2a of the drive motor 2 connected to the coupling mechanism 6 matches the amount of rotation of the motor shaft 4a of the motor under test 4, improving the accuracy of correcting the position data of the encoder 3 under test.
[0067] Embodiment 4. Next, the encoder correction device 100D according to Embodiment 4 will be described with reference to Figures 10 and 11. Figure 10 is a cross-sectional view showing the configuration of the encoder correction device 100D according to Embodiment 4, and shows the state in which the second jig 16b has moved to a position that supports the motor 4 under test. Figure 11 is a cross-sectional view showing the configuration of the encoder correction device 100D according to Embodiment 4, and shows the state in which the second jig 16b has moved to a position away from the motor 4 under test. This embodiment differs from Embodiments 1 to 3 described above in that the eccentricity absorption mechanism 7 and the angle deflection absorption mechanism 8 are the lifting mechanism 16, and the encoder correction device 100D is equipped with a rotation stopper mechanism 17 that restricts the circumferential movement of the motor body of the motor 4 under test. In Embodiment 4, parts that overlap with Embodiments 1 to 3 described above are denoted by the same reference numerals and their description is omitted.
[0068] As shown in Figures 10 and 11, the lifting mechanism 16 is a mechanism that supports the encoder 3 and motor 4 under test so that they can move along the vertical direction. The lifting mechanism 16 is also a mechanism that adjusts the motor shaft 4a of the motor under test 4 to be parallel to the central axis of the plurality of gripping claws 6c of the connecting mechanism 6. In this embodiment, the lifting mechanism 16 can adjust the inclination angle of the motor shaft 4a of the encoder 3 and motor 4 under test with respect to the axial direction. The lifting mechanism 16 is positioned between the base 5b and the rotation stopper mechanism 17 in the axial direction. The lifting mechanism 16 is positioned around the rotary chuck 6b and gripping claws 6c. The lifting mechanism 16 includes a first jig 16a, a second jig 16b, a plurality of shafts 16c, a plurality of bushings 16d, and a lifting cylinder 16e.
[0069] The first jig 16a is positioned on the frame 5. The first jig 16a is fixed to the base 5b. A mounting hole 16f for positioning the rotary chuck 6b is formed in the vertical center of the first jig 16a. The mounting hole 16f penetrates from one end face to the other end face of the first jig 16a in the axial direction. The shape of the mounting hole 16f is cylindrical with a constant diameter along its entire length in the axial direction.
[0070] The second jig 16b is a seating jig that is movable in the axial direction between a position supporting the motor 4 under test and a position away from the motor 4 under test. The second jig 16b supports the rotation stopper mechanism 17. The second jig 16b is positioned in the axial direction on one side of the first jig 16a with a gap 18 between them. A mounting hole 16g for positioning the motor shaft 4a and gripping claws 6c of the motor 4 under test is formed in the vertical center of the second jig 16b. The mounting hole 16g penetrates from one end face to the other end face of the second jig 16b in the axial direction. The shape of the mounting hole 16g is cylindrical with a constant diameter along its entire length in the axial direction. The diameter of the mounting hole 16g is larger than the outer diameter of the spigot portion of the motor body of the motor 4 under test, and smaller than the outermost diameter of the motor body. The motor body refers to the part of the motor 4 under test other than the motor shaft 4a.
[0071] The second jig 16b has a plurality of mounting holes 16h for installing the bush 16d. Each mounting hole 16h is arranged around the placement hole 16g. Each mounting hole 16h opens only on the other end face of the second jig 16b in the axial direction. Each mounting hole 16h is bottomed and cylindrical with a constant diameter along its entire length in the axial direction. A flat support surface 16j is formed on one end face of the second jig 16b in the axial direction. When the second jig 16b is moved to a position that supports the motor 4 under test, the support surface 16j contacts the vertically extending plane 4b of the motor 4 under test, supporting the motor 4 from the other side in the axial direction.
[0072] The shafts 16c and bushings 16d are members that guide the movement of the second jig 16b in the axial direction. Each shaft 16c is positioned between the first jig 16a and the second jig 16b in the axial direction. Each shaft 16c is fixed on the first jig 16a. Each shaft 16c is positioned around the portion of one end face of the first jig 16a in the axial direction where the mounting hole 16f is open. Each shaft 16c has a stepped cylindrical shape in which the diameter decreases from one end to the other in the axial direction. At the tip of each shaft 16c, there is an insertion portion 16i which is the smallest in diameter of each shaft 16c.
[0073] The bush 16d is a member into which the insertion portion 16i of the shaft 16c is slidably inserted. Each bush 16d has a cylindrical shape with a constant diameter along its entire axial length. Each bush 16d is installed in the installation hole 16h. Preferably, the shaft 16c and bush 16d are arranged at two or more equal intervals on the same circumference centered on the motor shaft 4a of the motor under test 4.
[0074] The lifting cylinder 16e is an actuator that controls the position of the second jig 16b in the axial direction. The lifting cylinder 16e is positioned between the first jig 16a and the second jig 16b in the axial direction. In this embodiment, there is one lifting cylinder 16e, but there may be multiple. The base end of the lifting cylinder 16e is fixed to one end face of the first jig 16a in the axial direction. The tip of the lifting cylinder 16e is fixed to the other end face of the second jig 16b in the axial direction. The lifting cylinder 16e is positioned outside the shaft 16c and the bush 16d. By driving the lifting cylinder 16e, the second jig 16b can move along the axial direction while being guided by the shaft 16c and the bush 16d. As the second jig 16b moves to a position away from the motor 4 under test, the encoder 3 and the motor 4 under test become floating relative to the second jig 16b (lifting mechanism 16), allowing them to tilt and move. Here, "floating" means a state in which the tilt and vertical position of the encoder 3 under test and the tilt and vertical position of the motor 4 under test can be freely changed.
[0075] The rotation-stopping mechanism 17 is a mechanism for restricting the circumferential rotation of the motor body of the motor under test 4. The rotation-stopping mechanism 17 restricts the circumferential rotation of the motor body of the motor under test 4, allowing only the motor shaft 4a of the motor under test 4 to rotate. The rotation-stopping mechanism 17 is also a mechanism that supports the encoder 3 and the motor under test 4 so that they can move along the vertical direction. In the illustrated example, the rotation-stopping mechanism 17 is fixed on the lifting mechanism 16, but it may also be fixed to the frame 5 via another member. The rotation-stopping mechanism 17 is arranged around the motor under test 4. The rotation-stopping mechanism 17 has a gripping mechanism 17a and a linear guide 17b.
[0076] The gripping mechanism 17a is capable of opening and closing vertically and is a mechanism for gripping the motor body of the motor under test 4 when closed. The gripping mechanism 17a has a plurality of rotation-stopping chucks 17c and a plurality of chuck jaws 17d.
[0077] The rotation-stopping chuck 17c is a drive component that drives the chuck jaws 17d, allowing it to approach and move away from the motor 4 under test in the vertical direction. The configuration of the rotation-stopping chuck 17c is not particularly limited, as long as it can drive the chuck jaws 17d. The rotation-stopping chuck 17c may be, for example, an air-operated air chuck or an electric chuck operated by a motor.
[0078] The chuck jaws 17d are components for gripping the motor under test 4. In this embodiment, the chuck jaws 17d automatically grip the motor under test 4 using the anti-rotation chuck 17c. In the examples shown in Figures 10 and 11, each of the multiple chuck jaws 17d approaches the motor under test 4 in the vertical direction, thereby gripping the motor under test 4 by sandwiching it between the multiple chuck jaws 17d. In this specification, the central axis of the chuck jaws 17d is defined as the central axis of the virtual circle formed by connecting the multiple chuck jaws 17d. Two chuck jaws 17d are positioned symmetrically on either side of the motor under test 4 in the vertical direction. Two anti-rotation chucks 17c are also positioned symmetrically on either side of the motor under test 4 in the vertical direction. In the examples shown in Figures 10 and 11, the chuck jaws 17d and the anti-rotation chuck 17c are positioned symmetrically on either side of the motor under test 4 in the left-right direction of the paper within the vertical plane. However, two more may be positioned symmetrically on either side of the motor under test 4 in the depth direction of the paper within the vertical plane.
[0079] The linear guide 17b is a member for supporting the gripping mechanism 17a so that it can move in a direction parallel to the opening and closing direction of the gripping mechanism 17a. The linear guide 17b has a plurality of rails 17e and a plurality of sliders 17f.
[0080] Each rail 17e is fixed on the second jig 16b. Each rail 17e extends in a straight line along the vertical direction.
[0081] The slider 17f is mounted on the rail 17e so as to be movable relative to it. One slider 17f is mounted on each rail 17e. The slider 17f is movable along the extension direction of the rail 17e. The two sliders 17f are positioned symmetrically on either side of the motor under test 4 in the vertical direction. The two rails 17e are also positioned symmetrically on either side of the motor under test 4 in the vertical direction. In the example shown in Figures 10 and 11, the sliders 17f and rails 17e are positioned symmetrically on either side of the motor under test 4 in the left-right direction of the paper in the vertical direction, but two more may be positioned symmetrically on either side of the motor under test 4 in the depth direction of the paper in the vertical direction. Each anti-rotation chuck 17c is fixed one on top of the slider 17f. This configuration allows the anti-rotation chuck 17c and chuck jaws 17d to move along the vertical direction. Specifically, by moving the slider 17f relative to the rail 17e along the extension direction, the rotation-stopping chuck 17c, chuck jaws 17d, the encoder 3 under test, and the motor 4 under test move in the vertical direction along the extension direction of the rail 17e. The opening and closing direction of the chuck jaws 17d coincides with the extension direction of the rail 17e.
[0082] Next, the positioning operation of the motor 4 under test will be described with reference to Figures 10 to 12. Figure 12 is a flowchart showing an example of the positioning operation process of the motor 4 under test in the encoder correction device 100D according to Embodiment 4.
[0083] First, in step S1, the motor under test 4 is placed on the second jig 16b. More specifically, when the second jig 16b has reached its upper limit due to the operation of the lifting cylinder 16e, the motor under test 4 is placed on the second jig 16b.
[0084] Next, in step S2, the motor shaft 4a is chucked by the gripping claws 6c of the connecting mechanism 6. At this time, if there is eccentricity or misalignment between the motor shaft 4a and the gripping claws 6c, the motor shaft 4a and the gripping claws 6c will be in point contact (see Figure 7).
[0085] Next, in step S3, the second jig 16b is lowered by the operation of the lifting cylinder 16e and moved to a position away from the motor 4 under test. As a result, the motor 4 under test is held only by the gripping claws 6c, and the motor shaft 4a of the motor 4 under test and the central axis of the gripping claws 6c of the connecting mechanism 6 can be adjusted to be on the same straight line (coaxial). As a result, the motor shaft 4a and the gripping claws 6c are in surface contact.
[0086] Next, in step S4, the rotation-stopping chuck 17c is driven to chuck the motor body of the motor under test 4 with the multiple chuck jaws 17d. At this time, in order to prevent the motor shaft 4a from tilting due to misalignment between the central axis of the chuck jaws 17d and the central axis of the gripping jaws 6c, the rotation-stopping chuck 17c and the chuck jaws 17d move along the extension direction of the rail 17e together with the slider 17f according to the chucking force. This automatically adjusts the positions of the rotation-stopping chuck 17c and the chuck jaws 17d in the vertical direction, and the central axis of the chuck jaws 17d and the central axis of the gripping jaws 6c can be adjusted coaxially. When the motor body of the motor under test 4 is chucked by the chuck jaws 17d, it is desirable that the position where the chuck jaws 17d chuck the motor body of the motor under test 4 is close to the gripping jaws 6c so that the moment on the motor shaft 4a is small. Also, for the same reason, it is desirable that the chuck jaws 17d be thin in the axial direction. By performing the above steps, the positioning of the motor 4 under test is completed.
[0087] Next, the effects of Embodiment 4 will be described.
[0088] In this embodiment, the eccentricity absorption mechanism 7 and the angle-shifting absorption mechanism 8 are a lifting mechanism 16 having a second jig 16b, which is a seating jig, and a lifting cylinder 16e, which is an actuator. The second jig 16b is movable in the axial direction between a position that supports the motor under test 4 and a position away from the motor under test 4. The lifting cylinder 16e controls the position of the second jig 16b in the axial direction. With this configuration, the motor under test 4 can be separated from the second jig 16b during testing. That is, when the motor under test 4 is connected to the drive motor 2 via the coupling mechanism 6, the motor under test 4 can be changed to a floating state away from the second jig 16b. As a result, the inclination angle of the encoder 3 and the motor under test 4 in the axial direction can be changed, and the encoder 3 and the motor under test 4 can be moved in the vertical direction. As a result, the central axes of the motor shaft 4a and the gripping claws 6c are arranged coaxially, resulting in surface contact between the motor shaft 4a and the gripping claws 6c, which prevents the motor shaft 4a from rolling. Therefore, the amount of rotation of the motor shaft 2a of the drive motor 2 connected to the coupling mechanism 6 matches the amount of rotation of the motor shaft 4a of the motor under test 4, improving the accuracy of correcting the position data of the encoder 3 under test.
[0089] When the motor under test 4 is separated from the second jig 16b, and the motor shaft 4a is rotated during the test due to the cogging torque of the motor under test 4, the motor body of the motor under test 4 may also rotate. In this embodiment, the encoder correction device 100D is equipped with a rotation-stopping mechanism 17 that limits the circumferential rotation of the motor body of the motor under test 4. The rotation-stopping mechanism 17 is vertically openable and closable and includes a gripping mechanism 17a that grips the motor body of the motor under test 4 when closed, and a linear guide 17b that supports the gripping mechanism 17a so that it can move in a direction parallel to the opening and closing direction of the gripping mechanism 17a. With these configurations, rotation of the motor body of the motor under test 4 during the test can be prevented, and tilting of the motor shaft 4a due to misalignment between the central axis of the chuck jaws 17d and the central axis of the gripping jaws 6c can be prevented. Therefore, the amount of rotation of the motor shaft 2a of the drive motor 2 connected to the coupling mechanism 6 matches the amount of rotation of the motor shaft 4a of the motor under test 4, which improves the accuracy of correcting the position data of the encoder 3 under test.
[0090] In this embodiment, the linear guide 17b includes a rail 17e and a slider 17f. The rail 17e extends vertically. The slider 17f is mounted on the rail 17e so as to be movable relative to it. The gripping mechanism 17a includes a rotation-stopping chuck 17c and chuck jaws 17d. The rotation-stopping chuck 17c drives the chuck jaws 17d to move closer to and further away from the motor under test 4 in the vertical direction. The chuck jaws 17d are configured to grip the motor under test 4. The rotation-stopping chuck 17c is attached to the slider 17f. With these configurations, by moving the slider 17f relative to it along the extending direction of the rail 17e, the rotation-stopping chuck 17c, chuck jaws 17d, the encoder under test 3, and the motor under test 4 can be moved vertically. In other words, when the motor under test 4 is connected to the drive motor 2 via the coupling mechanism 6, and when the motor under test 4 is gripped by the chuck jaws 17d, movement of the encoder 3 and the motor under test 4 in the vertical direction becomes possible. As a result, the central axes of the motor shaft 4a and the gripping jaws 6c are arranged coaxially, so the motor shaft 4a and the gripping jaws 6c make surface contact, preventing the motor shaft 4a from rolling. Therefore, the amount of rotation of the motor shaft 2a of the drive motor 2 connected to the coupling mechanism 6 matches the amount of rotation of the motor shaft 4a of the motor under test 4, improving the accuracy of correcting the position data of the encoder 3 under test. In short, in this embodiment, the lifting mechanism 16 can absorb the eccentricity of the motor shaft 4a, and the rotation stopping mechanism 17 further complements the absorption of the eccentricity of the motor shaft 4a by the lifting mechanism 16. This makes it possible to absorb the eccentricity of the motor shaft 4a more stably.
[0091] The configurations shown in the above embodiments are examples only, and it is possible to combine them with other known technologies, combine different embodiments, and omit or modify parts of the configuration without departing from the gist of the invention.
[0092] 1 Reference encoder, 2 Drive motor, 2a, 4a Motor shaft, 3 Encoder under test, 4 Motor under test, 4b Plane, 5 Stand, 5a Support column, 5b Base, 5c Mounting part, 5d Reduced diameter part, 5e Through hole, 6 Connecting mechanism, 6a Coupling, 6b Rotary chuck, 6c Gripping jaw, 6d Central axis, 6e Bellows coupling, 7 Eccentricity absorption mechanism, 7a First rail, 7b Second rail, 7c, 17f Slider, 8 Angle deflection absorption mechanism, 8a, 16a First jig, 8b, 16b Second jig, 8c Elastic member, 8d Bolt, 8e Nut, 8f Set screw, 8g, 8i, 12e, 13a, 16f, 16g Arrangement hole, 8h, 8j Insertion hole, 8k, 12f, 13b, 16j Support surface, 8m Screw hole, 9 Signal processing circuit, 9a SRAM area, 10 PC, 11, 18 Gap, 12 Spherical bearing, 12a Holder, 12b Ball, 12c Holding hole, 12d Sliding surface, 13 Receiving jig, 14 Pressing mechanism, 14a Support column, 14b Arm, 14c Contact part, 15 Drive device, 16 Lifting mechanism, 16c Shaft, 16d Bushing, 16e Lifting cylinder, 16h Installation hole, 16i Insertion part, 17 Rotation stopper mechanism, 17a Gripping mechanism, 17b Linear guide, 17c Rotation stopper chuck, 17d Chuck jaws, 17e Rail, 100, 100A, 100B, 100C, 100D Encoder correction device.
Claims
1. An encoder correction device for correcting an encoder under test that detects the position of a motor under test, comprising: a reference encoder; a drive motor attached to the reference encoder; an encoder under test positioned away from the reference encoder and the drive motor in the axial direction of the drive motor; a motor under test attached to the encoder under test; a coupling mechanism that connects the drive motor and the motor under test and has a gripping portion for gripping the motor shaft of the motor under test; an eccentricity absorption mechanism that supports the encoder under test and the motor under test so as to be movable along a vertical direction which is perpendicular to the axial direction of the drive motor; and an angle deviation absorption mechanism that adjusts the motor shaft of the motor under test and the central axis of the gripping portion of the coupling mechanism to be parallel.
2. The encoder correction device according to claim 1, characterized in that the eccentricity absorption mechanism is an orthogonal linear guide having: a first rail extending in one of the vertical directions; a second rail attached to the first rail so as to be movable relative to it and extending in a direction different from the extension direction of the first rail in the vertical direction; and a slider attached to the second rail so as to be movable relative to it and attached to the motor under test via another member.
3. The encoder correction device according to claim 1 or 2, characterized in that the angle deflection absorption mechanism comprises: a first jig; a second jig positioned on one side of the first jig in the axial direction with a gap between them and supporting the motor under test; an elastic member positioned between the first jig and the second jig and biasing the first jig and the second jig in a direction separating them from each other by elastic force; and a pressing member connecting the first jig and the second jig.
4. The encoder correction device according to claim 3, characterized in that the elastic member and the pressing member are arranged at three or more equal intervals on the same circumference centered on the motor shaft of the motor under test.
5. The encoder correction device according to claim 3 or 4, characterized in that the elastic force of the elastic member is greater than the load of the motor under test and less than the gripping force of the gripping portion of the coupling mechanism.
6. The encoder correction device according to any one of claims 3 to 5, characterized in that the elastic member and the pressing member are arranged at the same position on the same circumference centered on the motor shaft of the motor under test.
7. The encoder correction device according to any one of claims 3 to 6, characterized in that the angle deflection absorption mechanism has a set screw for temporarily fixing the second jig to the first jig in a way that prevents it from moving.
8. The encoder correction device according to claim 1 or 2, characterized in that the angle deflection absorption mechanism is a spherical bearing having a holder and a ball that slides within the holder.
9. The encoder correction device according to claim 1 or 2, wherein the coupling mechanism includes a bellows coupling, and the bellows coupling constitutes the angle deflection absorption mechanism.
10. The encoder correction device according to claim 1, characterized in that the eccentricity absorption mechanism and the angle deflection absorption mechanism are a lifting mechanism comprising: a seat jig that is movable in the axial direction between a position supporting the motor under test and a position away from the motor under test; and an actuator that controls the position of the seat jig in the axial direction.
11. An encoder correction device according to any one of claims 1 to 10, comprising a rotation-stopping mechanism that restricts the circumferential rotation of the motor body of the motor under test, wherein the rotation-stopping mechanism comprises a gripping mechanism that is openable and closable in the vertical direction and grips the motor body of the motor under test when closed, and a linear guide that supports the gripping mechanism so as to be movable in a direction parallel to the opening and closing direction of the gripping mechanism.
12. A method for manufacturing an encoder in which the encoder used to correct the position of the motor under test by using an encoder correction device comprising: a reference encoder; a drive motor attached to the reference encoder; an encoder under test positioned away from the reference encoder and the drive motor in the axial direction of the drive motor; a motor under test attached to the encoder under test; a coupling mechanism that connects the drive motor and the motor under test and has a gripping portion for gripping the motor shaft of the motor under test; an eccentricity absorption mechanism that supports the encoder under test and the motor under test so as to be movable along a vertical direction perpendicular to the axial direction of the drive motor; and an angle deviation absorption mechanism that adjusts the motor shaft of the motor under test and the central axis of the gripping portion of the coupling mechanism to be parallel, the method comprising a coupling step of connecting the drive motor and the motor under test using the coupling mechanism, The method for manufacturing an encoder, characterized in that, in the coupling step, the eccentricity absorption mechanism moves the encoder under test and the motor under test along the vertical direction, and the angle-shifting absorption mechanism adjusts the motor shaft of the motor under test and the central axis of the gripping portion of the coupling mechanism to be parallel.