JP7640766B2 - Apparatus and method for inspecting the position of stator coil terminals - Google Patents

Description

The present invention relates to the manufacturing process of stators that constitute motors, and in particular to a stator coil terminal posture inspection device and posture inspection method that inspect the posture of the coil terminals in order to properly manage the posture of the stator coil terminals.

Generally, a stator coil consists of multiple coils wound around a stator core (stator iron core), which has a circular outer shape and multiple teeth (internal teeth) on its inside. The stator coils are inserted into slots formed between adjacent teeth and wound around the teeth.

Generally, a stator coil has multiple segment coils. The insulating coating on the coil terminals of the segment coils is first stripped off and the coils are inserted into the slots of the stator core. The segment coils are then stacked at the coil terminals of the same phase. The tips of the coil terminals are then joined by welding or other methods to produce the coil.

Properly managing the position of the coil terminals is extremely important to prevent short circuits and unstable motor characteristics caused by contact between coils, and to prevent assembly problems in later processes. The position of the coil terminals can be inspected by visual inspection, electrical continuity inspection, image capture and processing, and image capture using laser irradiation.

For example, Patent Document 1 describes that in order to ensure that the positional accuracy at the tip of the coil terminal falls within a predetermined standard value, after the segment coil is assembled to the stator core, and before the coil terminals of the same phase are joined together, the position of each coil terminal is measured by image measurement to determine whether the positional accuracy is good or bad.

Patent Document 2 also describes a method for detecting the amount of misalignment between two welded ends by irradiating the tip surfaces of the two welded ends with laser light from an oblique direction on first and second lines that cross the mating surface, and calculating the amount of misalignment from an image captured by an imaging device.

JP 2014-135819 A JP 2020-28904 A

In the above conventional technology, visual inspection methods place a heavy burden on inspectors, and as they become fatigued, there is a risk that they may overlook contact between coil terminals that could lead to a short circuit. In addition, inspection methods based on electrical continuity are time-consuming depending on the scale of the wiring work. Even if the electrical continuity inspection passes, it does not indicate the position of the coil terminals, and it is not possible to determine whether or not a defect will occur in the assembly process in the later stages.

Patent Document 1 relies on image capture and processing, so even if image data is simply collected, it is not easy to accurately capture the position of the coil terminal due to the effects of light and shadow. Therefore, some kind of calculation processing and algorithms are required, which results in an expensive inspection system.

In addition, in Patent Document 2, the inspection is performed by irradiating a laser and taking an image, so it is not easy to adjust the amount of light from the laser, making it difficult to perform accurate inspection.

The object of the present invention is to provide a method and device for inspecting the posture of stator coil terminals that solves the problems of the conventional technology and can determine whether defects caused by contact between coils that affect electrical characteristics and defects that may occur during subsequent assembly processes can be detected by inspecting the posture of the coil terminals.

To achieve the above objective, the present invention has the following configuration.

[1]
A stator coil terminal posture inspection device that inspects the posture of a coil terminal of a coil wound around a stator core of a stator that constitutes a motor, comprising: an inspection probe that inspects the posture of the coil terminal; and a control device that moves the inspection probe at least in the radial direction of the stator coil, passing it through a gap between adjacent coil terminals, and detects whether or not the inspection probe is in contact with the coil terminal.
[2]
The apparatus for inspecting the posture of a stator coil terminal according to claim 1, wherein the inspection probe is set to a value smaller than the gap between the coil terminals by a predetermined value.
[3]
The stator coil terminal posture inspection device according to [1] or [2], characterized in that the presence or absence of contact between the inspection probe and the coil terminal is detected by detecting the displacement of the inspection probe using a proximity switch provided near the inspection probe.
[4]
The posture inspection device for a stator coil terminal described in any one of [1] to [3] is characterized in that the inspection probe is provided with a radial unit to which a radial probe is attached and which can be moved in the up, down, left, and right directions.
[5]
A method for inspecting the posture of a stator coil terminal, which inspects the posture of a coil terminal of a coil wound around a stator core of a stator that constitutes a motor, comprising the steps of: moving an inspection probe for inspecting the posture of the coil terminal at least in the radial direction of the stator coil, passing it through a gap between adjacent coil terminals, and detecting whether or not the inspection probe is in contact with the coil terminal.
[6]
The method for inspecting the posture of a stator coil terminal described in [5] is characterized in that the inspection probe for performing the radial inspection is provided with a radial unit to which a radial probe is attached, and the method detects whether or not there is contact between the radial probe and the coil terminal in the radial direction.

In another embodiment of the present invention, a stator coil terminal posture inspection device that inspects the posture of the coil terminal of a coil wound around a stator core of a stator that constitutes a motor includes a rotating table on which the stator is placed, a rotating table motor that rotates the rotating table, an inspection probe that inspects the posture of the coil terminal, and a control device that moves the inspection probe and drives the rotating table motor, passes the inspection probe through the gap between adjacent coil terminals, and detects whether the inspection probe is in contact with the coil terminal.

Furthermore, in the above-mentioned stator coil terminal posture inspection device, when the control device detects contact between the inspection probe and the coil terminal, it is desirable to determine and store the position from the rotation angle of the rotating table.

Furthermore, in the above-mentioned stator coil terminal posture inspection device, it is desirable that the inspection probe is set to a value that is a predetermined value smaller than the gap between the coil terminals.

Furthermore, in the above-mentioned stator coil terminal posture inspection device, it is preferable that the presence or absence of contact between the inspection probe and the coil terminal is detected by detecting the displacement of the inspection probe using a proximity switch provided near the inspection probe.

In addition, in the above-mentioned stator coil terminal posture inspection device, it is preferable to provide a circumferential unit to which a circumferential probe is attached as the inspection probe for inspecting the stator in the circumferential direction and which can be moved in the up, down, left and right directions, and a radial unit to which a radial probe is attached as the inspection probe for inspecting the stator in the radial direction and which can be moved in the up, down, left and right directions.

Furthermore, in the above-mentioned stator coil terminal posture inspection device, it is preferable that the circumferential probes are multiple.

Furthermore, in the above-mentioned stator coil terminal posture inspection device, it is preferable that the circumferential unit comprises a probe base supported by a linear motion guide from a guide table and having the circumferential probe attached thereto, a fulcrum plate supported by a second linear motion guide from the probe base, a spring provided between the probe base and the fulcrum plate for pressing the fulcrum plate downward, and a means for detecting the displacement of the fulcrum plate.

To achieve the above object, the present invention provides a method for inspecting the posture of a stator coil terminal, which inspects the posture of the coil terminal of a coil wound around a stator core of a stator that constitutes a motor, by moving an inspection probe that inspects the posture of the coil terminal and driving a rotary table motor that rotates a rotary table on which the stator is placed, passing the inspection probe through the gap between adjacent coil terminals, and detecting whether or not the inspection probe is in contact with the coil terminal.

In addition, in the above-mentioned method for inspecting the posture of a stator coil terminal, when contact between the inspection probe and the coil terminal is detected, it is desirable to determine and store the position from the rotation angle of the rotating table.

In addition, the above-mentioned method for inspecting the posture of a stator coil terminal includes a circumferential unit to which a circumferential probe is attached as the inspection probe for inspecting the stator in the circumferential direction, and a radial unit to which a radial probe is attached as the inspection probe for inspecting the radial direction, and it is preferable to detect the presence or absence of contact between the circumferential probe and the coil terminal in the circumferential direction of the stator, and to detect the presence or absence of contact between the radial probe and the coil terminal in the radial direction.

According to the present invention, the stator coil terminal posture inspection device moves an inspection probe that inspects the posture of the coil terminal and drives a rotating table motor, passes the inspection probe between adjacent coil terminals, and detects whether the inspection probe is in contact with the coil terminal, so that the posture of the coil terminal can be directly inspected. Therefore, the present invention can improve the yield by determining assembly defects in later processes and improve the reliability of assembled motors.

FIG. 1 is a perspective view showing a main part of an inspection device according to an embodiment of the present invention; FIG. 1 is a perspective view of a stator 6 constituting a motor to be inspected. FIG. 1 is an enlarged view showing details of an inspection unit according to one embodiment; A flowchart showing a circumferential inspection process according to one embodiment. 1 is a flow chart showing a radial inspection process according to one embodiment. FIG. 1 is a detailed side view of a circumferential unit 3 according to an embodiment; FIG. 7 is a detailed side view showing a relieving state of the circumferential unit 3 in FIG. FIG. 13 is a partial enlarged view showing details of a circumferential direction inspection unit according to an embodiment; FIG. 1 is an enlarged view showing the relationship between the coil end gap and the circumferential probes 3-1 and 3-2 according to one embodiment. FIG. 13 is a partial enlarged view showing details of a radial inspection unit according to an embodiment; FIG. 1 is a plan view showing a radial probe 4-1 according to another embodiment; Further, a detailed side view of the circumferential unit 3 according to another embodiment FIG. 13 is a detailed side view showing a relieving state of the circumferential unit 3 according to another embodiment of the present invention;

Figure 1 is a perspective view showing the main parts of the inspection device, and Figure 2 is a perspective view of a stator 6 that constitutes a motor to be inspected. The stator 6 is placed and set on a rotating table 1. The rotating table motor 2 rotates the rotating table 1 via a belt 2-1. The inspection device passes a rod-shaped inspection probe made of metal or plastic and having a predetermined size between adjacent coil terminals 6-6. The inspection device then detects whether or not there is contact between the inspection probe, which inspects the posture of the coil terminals, and the coil terminals 6-6, and inspects the posture of the coil terminals 6-6.

The circumferential unit 3 is fitted with circumferential probes 3-1 and 3-2 as inspection probes for inspecting the stator 6 in the circumferential direction, and is capable of moving up, down, left and right. Similarly, the radial unit 4 is fitted with radial probe 4-1 as an inspection probe for inspecting the radial direction, and is capable of moving up, down, left and right. The vertical movement of the circumferential probes 3-1 and 3-2 is performed by air cylinder 3-15, and the horizontal movement of the radial probe 4-1 is performed by air cylinder 4-4.

The stator 6 comprises a stator core 6-1 and a stator coil 6-2. The stator core 6-1 has a plurality of slots 6-4 drilled radially from a cylindrical inner peripheral surface 6-3 at equal intervals in the circumferential direction. A U-shaped stator coil 6-2 made of rectangular wire is inserted into the slots 6-4 as multiple segment coils stacked in multiple layers in the radial direction.

The stator coil 6-2 has coil terminals 6-6 that protrude upward a predetermined length from the upper end of the stator core 6-1. The stator coil 6-2 has coil bridge portions 6-5 that protrude downward a predetermined length from the lower end of the stator core 6-1. The coil terminals 6-6 are twisted in the circumferential direction to join the coil terminals 6-6 of the same phase that are inserted into different slots 6-4.

Figure 3 is an enlarged view showing the details of the inspection section. This figure shows an example in which the stator coil 6-2 is stacked in three layers in the radial direction. Therefore, since there are two gaps between the coil terminals 6-6 in the radial direction, the circumferential unit 3 has two circumferential probes 3-1 and 3-2 attached at fulcrums 3-5 and 3-6. The lower end of the circumferential probe 3-1 is at the gap B between the coil terminals, and the upper end extends beyond the fulcrum 3-5. In addition, the length from the lower end to the fulcrum 3-5 is longer than the length from the fulcrum 3-5 to the upper end, and the displacement of the lower end is detected by the proximity switch 3-3 provided near the upper end, which detects the displacement of the circumferential probe 3-2 on the outer periphery.

The same is true for the inner circumference side, where the displacement of the lower end of the inner circumference side circumferential probe 3-1 is detected by the proximity SW 3-4 provided at the upper end. When three or more layers are stacked, the number of circumferential probes 3-1, 3-2 may be increased to two or more. In addition, in FIG. 3, the displacement detection of the circumferential probes 3-1, 3-2 is performed by the proximity SW 3-3, 3-4 provided at the upper end, but it is not limited to the upper end, and may be performed at the lower end side or horizontal position from the fulcrums 3-5, 3-6. In other words, the presence or absence of contact between the inspection probe and the coil terminal 6-6 is detected by detecting the displacement of the inspection probe by the proximity SW 3-3, 3-4 provided near the inspection probe.

Similarly, the radial unit 4 has the radial probe 4-1 attached at the fulcrum 4-3. The length from the lower end to the fulcrum 4-3 is longer than the length from the fulcrum 4-3 to the upper end, and the displacement of the radial probe 4-1 at the lower end is detected by the proximity switch 4-2 provided at the upper end. Each of the circumferential probes 3-1, 3-2 and the radial probe 4-1 is made of metal, and each of the proximity switches 3-3, 3-4, 4-2 is suitably a magnetic type non-contact displacement sensor.

Although not shown, the inspection device is also provided with a control device having a memory device. The control device moves the circumferential unit 3 and radial unit 4 and drives the turntable motor 2, causing the circumferential unit 3 and radial unit 4 to pass between adjacent coil terminals 6-6. The control device receives inputs from proximity switches 3-3, 3-4, 4-2, etc., and detects whether or not there is contact between the circumferential probes 3-1, 3-2 and radial probe 4-1 and the coil terminals 6-6, stores the positions where there is contact, and generates an alarm, etc.

Figure 4 is a flowchart showing the circumferential inspection process, Figure 5 is a flowchart showing the radial inspection process, Figure 6 is a detailed side view of the circumferential unit 3, Figure 7 is a detailed side view showing the relieving state of the circumferential unit 3, Figure 8 is a partially enlarged view showing the details of the circumferential inspection section, Figure 9 is an enlarged view showing the relationship between the gap between the coil terminals 6-6 and the circumferential probes 3-1 and 3-2, and Figure 10 is a partially enlarged view showing the details of the radial inspection section.

First, the inspection worker assembles the stator coil 6-2 to the stator core 6-1 and welds the coil end 6-6. The stator 6, which is the item to be inspected, is then set on the rotating table 1 of the inspection device. Next, the circumferential unit 3 is lowered by the air cylinder 3-15 so that the lower ends of the circumferential probes 3-1 and 3-2 reach the bottom of the gap B between the coil ends.

As shown in Figure 6, the circumferential unit 3 has a probe base 3-11 supported by a linear motion guide 3-7 from a guide table 3-10, and the circumferential probes 3-1 and 3-2 are moved up and down by an air cylinder 3-15. Proximity switches 3-3 and 3-4 are attached to the probe base 3-11. The fulcrum plate 3-12 is supported by a second linear motion guide 3-8 from the probe base 3-11.

The spring 3-9 is provided between the probe base 3-11 and the fulcrum plate 3-12, and presses the fulcrum plate 3-12 downward. The circumferential probes 3-1 and 3-2 are axially supported at the fulcrum 3-5 of the fulcrum plate 3-12. The second proximity SW 3-13 detects the displacement of the fulcrum plate 3-12.

Figure 7 shows the state (relieving state) when the lower ends of the circumferential probes 3-1, 3-2 cannot descend to the bottom of the gap B between the coil terminals and come into contact with the coil terminal 6-6. In this state, an upward force is applied to the fulcrum plate 3-12 as shown by the arrow, but this is relieved (buffered) by the spring 3-9, and the circumferential probes 3-1, 3-2 are structured to escape upward by the second linear motion guide 3-8. Also, during relieving, the second proximity SW 3-13, which serves as a means for detecting the displacement of the fulcrum plate 3-12, is turned off, making detection possible.

The rotating table 1 rotates as shown by the arrow in Figure 8 after the lower ends of the circumferential probes 3-1 and 3-2 have moved to the bottom of the gap B between the coil terminals. As a result, the control device passes the circumferential probes 3-1 and 3-2, which are inspection probes, through the gap B between the adjacent coil terminals to detect whether or not there is contact between the coil terminals 6-6. If the gap B between the coil terminals is inappropriate and the circumferential probes 3-1 and 3-2 come into contact with the coil terminal 6-6, the circumferential probes 3-1 and 3-2 rotate around the fulcrum 3-5. This movement is detected when the detection point 3-14 moves out of contact with the proximity switches 3-3 and 3-4.

When contact is detected, the posture inspection device can select case 1, "stop the inspection and issue an alarm," or case 2, "continue the inspection and issue an alarm after all inspections are completed." This selection is determined according to the needs of the customer, etc. In addition, the control device determines the position of contact from the reference position 6-7 in the rotation direction of the stator 6, based on the rotation angle of the turntable 1 at the time contact is detected, and stores it.

If the control device detects no contact after rotating the turntable 1 once, it determines that the position of the coil terminal 6-6 in the circumferential direction is good, and moves the circumferential unit 3 upward from the coil terminal 6-6 and returns it to its original position. Note that the circumferential rotation of the turntable 1 takes 6 seconds or less per revolution.

As shown in FIG. 9, the circumferential probes 3-1 and 3-2, which are inspection probes, are rod-shaped, and their diameter (probe diameter A) is set to a value that is a predetermined value smaller than the gap B between the coil terminals in order to properly maintain the posture of the coil terminals 6-6. The predetermined value is preferably 0.6 to 1.0 mm. These values are determined by the variation in the width of the welded portion. The same is true for the radial probe 4-1, whose diameter is approximately the same as that of the circumferential probes 3-1 and 3-2.

If the coil terminal 6-6 is not properly oriented and falls or shifts, the gap B between the coil terminals will be smaller than the diameter of the circumferential probes 3-1 and 3-2. As a result, the circumferential probes 3-1 and 3-2 come into contact with the coil terminal 6-6 and rotate around the fulcrum 3-5. The proximity switches 3-3 and 3-4 detect the rotation of the circumferential probes 3-1 and 3-2 and turn on, and the control device judges the product to be non-compliant and classifies the test object as non-compliant.

After the circumferential unit 3 has returned to its original position, as shown in the flow chart of FIG. 5, the radial unit 4 descends to the coil terminal 6-6, and the lower end of the radial probe 4-1 descends to the bottom of the gap C1 between the coil terminals. Then, in the initial position, the radial probe 4-1 is moved back and forth in the radial direction as shown in FIG. 10. As a result, the control device passes the radial probe 4-1, which is an inspection probe, through the gaps C1 to C3 between adjacent coil terminals (see FIG. 11) to detect whether or not it is in contact with the coil terminal 6-6. After the initial position is complete, the rotating table 1 is rotated by a specified angle, and the detection of whether or not it is in contact is repeated until it is completed around the entire circumference.

The speed at which the radial probe 4-1 and the rotating table 1 are rotated is adjusted so that the inspection time for the entire circumference is 30 seconds or less. Generally, 60 to 70 seconds or less is desirable. The gap C1 between the coil terminals on the innermost radial side is the narrowest compared to the outer peripheral side, and is more prone to non-conformities in manufacturing compared to the outer peripheral side, so the diameter of the radial probe 4-1 is set based on the gap C1 between the coil terminals on the innermost radial side.

As with the circumferential direction, when contact is detected, the posture inspection device can select case 1, "stop the inspection and issue an alarm," or case 2, "continue the inspection and issue an alarm after all inspections are completed." The control device then determines the contact position from the reference position 6-7 in the rotation direction of the stator 6 based on the rotation angle of the turntable 1 at the time of contact and stores it.

After all inspections of the stator coil 6-2 are completed, if the product passes the inspection, an output to that effect is issued. If contact is detected, the position of the contact is output. Note that, although the above explanation was given assuming that the circumferential inspection process is performed before the radial inspection process, the order may be reversed, with the radial inspection process being performed before the circumferential inspection process. In any case, this inspection method can directly determine the orientation of the coil terminal 6-6 itself, improving the yield in assembling the motor and ultimately improving the reliability of the assembled motor.

Figure 11 is a plan view showing another embodiment of the radial probe 4-1. The radial probe 4-1 shown in Figure 10 is set based on the gap C1 between the coil terminals on the innermost circumference side, and detects the presence or absence of contact with the radial probe 4-1 of the same diameter from the inside to the outer circumference side. For example, it is preferable that the diameter of the radial probe 4-1 shown in Figure 10 is the gap C1 between the coil terminals on the innermost circumference side - (0.6 to 1) mm. However, if the outer circumference side is also to be inspected, that is, if it is to be confirmed that the coil terminals 6-6 on the outer circumference side are not tilted, it is better to make the radial probe 4-1 trapezoidal in plan view.

When the radial probe 4-1 is trapezoidal as shown in FIG. 11, it is preferable that the innermost probe diameter A1 is the gap between the coil terminals on the innermost side C1 - (0.6 to 1) mm, the intermediate probe diameter A2 is the gap between the intermediate coil terminals C2 - (0.6 to 1) mm, and the outermost probe diameter A3 is the gap between the coil terminals on the outermost side C3 - (0.6 to 1) mm. Of course, since the trapezoid shape of the radial probe 4-1 satisfies C1 < C2 < C3, A1 < A2 < A3.

Figure 12 is a detailed side view showing another embodiment of the circumferential unit 3, and Figure 13 is a detailed side view showing the relieving state of the other embodiment of the circumferential unit 3. The difference from Figure 6 is that the lower ends of the circumferential probes 3-1 and 3-2 extend horizontally from the gap B between the coil terminals to the fulcrum 3-5, and the opposite side of the fulcrums 3-5 and 3-6. The proximity switches 3-3 and 3-4 are positioned horizontally above the fulcrums 3-5 and 3-6.

As a result, the proximity switches 3-3 and 3-4 also function as a means for detecting the displacement of the fulcrum plate 3-12. Therefore, the relieving state can be detected even if the second proximity switch 3-13 is omitted. The relieving state movement in FIG. 13 is achieved by the detection point 3-14 of the circumferential probes 3-1 and 3-2 moving away from the proximity switches 3-3 and 3-4. When the circumferential probes 3-1 and 3-2 come into contact with the coil terminal 6-6, they rotate around the fulcrum 3-5, and are detected by the detection point 3-14 moving away from the proximity switches 3-3 and 3-4.

1... Rotating table 2... Rotating table motor 2-1... Belt 3... Circumferential direction unit 3-1, 3-2... Circumferential direction probe 3-3, 3-4, 4-2... Proximity SW
3-5, 3-6... fulcrum 3-15, 4-4... air cylinder 3-7... linear motion guide 3-8... second linear motion guide 3-9... spring 3-10... guide base 3-11... probe base 3-12... fulcrum plate 3-13... second proximity SW
3-14...detection point 4...radial unit 4-1...radial probe 4-3...fulcrum 6...stator 6-1...stator core 6-2...stator coil 6-3...inner circumferential surface 6-4...slot 6-5...coil crossover portion 6-6...coil terminal 6-7...reference positions A, A1, A2, A3...probe diameter B, C1, C2, C3...gap between coil terminals

Claims (5)

In a stator coil terminal posture inspection device for inspecting the posture of a coil terminal of a coil wound around a stator core of a stator constituting a motor,
an inspection probe for inspecting the attitude of the coil terminal;
a control device that moves the inspection probe at least in a radial direction of the stator coil and passes the inspection probe through a gap between adjacent coil terminals, and detects whether or not the inspection probe is in contact with the coil terminals;
A stator coil terminal posture inspection device comprising: 2. The stator coil terminal posture inspection device according to claim 1 , wherein the presence or absence of contact between the inspection probe and the coil terminal is detected by detecting the displacement of the inspection probe using a proximity switch provided near the inspection probe. 3. The posture inspection device for a stator coil terminal according to claim 1, further comprising a radial unit to which a radial probe is attached as the inspection probe and which is movable in the up, down, left and right directions. A method for inspecting the posture of a coil terminal of a coil wound around a stator core of a stator constituting a motor, comprising:
A method for inspecting the posture of a stator coil terminal, comprising: moving an inspection probe for inspecting the posture of the coil terminal at least in the radial direction of the stator coil, passing it through a gap between adjacent coil terminals, and detecting whether or not the inspection probe is in contact with the coil terminal. The method for inspecting the posture of a stator coil terminal as described in claim 4, characterized in that the inspection probe for performing the radial inspection is provided with a radial unit to which a radial probe is attached, and the presence or absence of contact between the radial probe and the coil terminal in the radial direction is detected.