Stepping motor pin insertion method

Abstract

The application discloses a step motor pin inserting method and relates to the technical field of micro special motor manufacturing process. The step motor pin inserting method comprises the following steps executed in sequence: S1, pin feeding: PIN pins are sequentially sorted and fed to the preset insertion position of the pin inserting station, and the axial and circumferential initial positioning of the pin body is completed; S2, visual detection of pin positioning: the end face and side profile information of the PIN pin are acquired through a multi-view visual acquisition system, and are compared with the preset reference coordinates. The step motor pin inserting method. The mechanical interlocking structure formed by the flower texture and the plastic makes the axial pulling force of the PIN pin 3-5 times higher than that of the traditional smooth pin interference press fitting process. The actual measured average pulling force can reach more than 60N, and the binding force is not dependent on the elastic holding of the plastic. After high-low temperature cycle and long-term vibration, the attenuation rate is less than 10%. The electrical failure problem caused by PIN pin movement and falling can be completely eliminated, and the average fault-free operation time of the motor is increased by more than 2 times.

Description

Technical Field

[0001] This invention relates to the field of micro-motor manufacturing technology, and in particular to a stepper motor pin insertion method. Background Technology

[0002] Stepper motors, as core actuators for precision control, are widely used in printers, scanners, smart home devices, and industrial transmission devices. The cable tray frame is the core insulating structure of the stepper motor, and the pins inserted into its pin holes are the only electrical connection bridge between the stator coil and the external drive circuit. The quality of the insertion directly determines the electrical reliability and service life of the motor.

[0003] Currently, the stepper motor frame pins in the industry generally adopt a one-time interference press-in process: the smooth metal pin is directly pressed into the pre-made pin hole of the plastic frame through the press head, and the pin is fixed by the elastic clamping force generated by the compression of the plastic hole wall.

[0004] This process relies solely on the static friction between the smooth metal surface and the plastic to achieve the bonding between the PIN pin and the skeleton, resulting in a low upper limit for axial bonding force and poor stability.

[0005] During the coil winding process, the tension of the enameled wire will directly act on the PIN needle, which can easily cause the needle body to move axially.

[0006] The high-frequency vibration generated by the long-term operation of the motor, as well as the relaxation of plastic stress caused by high and low temperature environmental cycles, will further weaken the clamping force of the hole wall, eventually causing the PIN pin to loosen or even fall off completely, resulting in the coil wiring being disconnected and the motor failing to be powered on.

[0007] In response to this problem, the industry has tried various improvement solutions. Some manufacturers have increased the clamping force by increasing the interference between the pin hole and the PIN pin. However, excessive interference can cause the plastic skeleton to crack and the PIN pin to bend and deform, which will increase the defect rate. Some manufacturers have adopted the method of applying glue after inserting the pin for reinforcement. However, there are problems such as glue overflow contaminating the welding surface of the pin body, long glue curing cycle, and a significant decrease in production efficiency. Moreover, the glue will age and become brittle after long-term use, which still cannot solve the long-term reliability problem.

[0008] In summary, existing technologies have consistently failed to fundamentally solve the problem of insufficient axial anti-detachment capability of PIN needles while ensuring processing efficiency and avoiding damage to the skeleton and needle body. Summary of the Invention

[0009] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a stepper motor pin insertion method that can solve the problems in the background art mentioned above.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a stepper motor pin insertion method, comprising the following steps performed sequentially:

[0011] S1. Needle feeding: After sorting and arranging the PIN needles one by one, feed them to the preset insertion position of the needle insertion station to complete the initial axial and circumferential positioning of the needle body.

[0012] S2. Visual inspection of pin positioning: The end face and side profile information of the PIN pin are obtained through a multi-view visual acquisition system and compared with the preset reference coordinates to confirm that the position and posture accuracy of the PIN pin meet the pin insertion threshold requirements.

[0013] S3. Initial pin insertion into the frame: The servo pressing mechanism is used to insert the PIN pins into the corresponding pin holes of the stepper motor frame at a uniform speed to complete the pre-positioning insertion. The insertion depth of the PIN pin is 30%~50% of the total depth of the pin hole. The length of the pin exposed on the frame surface is reserved for the texturing process.

[0014] S4. Engraving treatment: A symmetrical stamping mechanism is used to cold stamp and engrave the exposed PIN pin roots after initial insertion, forming multiple sets of circumferentially distributed anti-detachment textures on the pin body surface.

[0015] S5. Skeleton pin in place: Continue to press the PIN pin with the completed texturing treatment into the pin hole along the pin hole axis at a uniform speed until the PIN pin reaches the design limit position inside the pin hole. After holding the pressure for a set time, release the pressure so that the anti-loose texture and the plastic inner wall of the pin hole form a mechanical interlocking fit.

[0016] S6. Pin bending: The end of the PIN pin exposed outside the frame is first pre-bent and buffered, and then the final bend at a set angle is completed to form a standardized wiring pin.

[0017] Preferably, in step S1, the PIN needles are spirally sorted by the guide vibrating plate and then conveyed to the sorting station by the straight vibrating feeding track. They are then separated one by one by the sorting blocks and pushed to the clamp to be inserted.

[0018] The clamping fixture uses a V-shaped positioning groove and an end face stop to hold the PIN pin. The clamping force is controlled at 5~10N, which ensures positioning accuracy and avoids damaging the pin body plating.

[0019] Preferably, the multi-view vision acquisition system in step S2 includes a top coaxial light camera and a side diffuse light camera. The top camera acquires the pin end face profile to identify the horizontal offset, and the side camera acquires the pin body side profile to identify the axial tilt angle.

[0020] When the position deviation exceeds ±0.02mm or the angle deviation exceeds ±0.5°, the servo fine-tuning platform drives the fixture to be inserted to complete the position correction. After correction, a second inspection is carried out. Only after passing the inspection can the pin insertion process begin.

[0021] Preferably, the initial insertion of the pin in step S3 adopts segmented variable speed pressing: the front section travels quickly at 20~30mm / s to the position 0.5mm at the pin hole entrance, and the rear section presses in at a low speed of 10~15mm / s to the target depth.

[0022] During the pressing process, the pressing force is monitored in real time by a pressure sensor. When the pressing force exceeds the preset upper limit of 30N, it is determined that the needle hole is misaligned or the needle body is deformed, and the machine will automatically stop and alarm.

[0023] Preferably, the symmetrical stamping mechanism in step S4 includes two sets of carbide press heads arranged opposite each other, and the working surface of the press head is provided with raised teeth that match the texture.

[0024] During stamping, the two sets of pressure heads are fed synchronously, with a feed accuracy controlled at ±0.01mm. One to two sets of barbed grooves are formed on each of the two opposite sides of the PIN pin. The groove cross-section is a right trapezoid with a depth of 0.05 to 0.15mm, an axial length of 1 to 2mm, and a tooth pitch of 0.3 to 0.6mm.

[0025] Preferably, the insertion of the pin in step S5 adopts a constant force pressing mode, with the pressing force set to 50~120N and the pressing speed to 5~10mm / s;

[0026] After pressing to the target depth, hold the pressure for 0.3~0.8s to allow the plastic material on the inner wall of the pinhole to undergo sufficient plastic deformation and fill the groove of the anti-detachment texture. After holding the pressure, the press head retracts at a constant speed to avoid the pin rebounding.

[0027] Preferably, in step S6, the pre-bending buffer uses an arc pusher to bend the end of the PIN pin by 30°~45° first, and the final bending uses a right-angle bending die to bend the pin to 90°. The bending radius is 0.5~1 times the side length of the PIN pin cross-section.

[0028] During the bending process, the base of the PIN needle is supported by a support pad. The support pad fits against the surface of the skeleton, offsetting the radial force of bending and preventing the base of the needle from loosening.

[0029] Preferably, before step S3, a skeleton feeding and calibration step is included: the stepper motor skeleton is sorted and transported to the positioning carrier of the pin insertion fixture via a skeleton vibration plate, and the initial positioning is completed by inserting the elastic positioning pin into the reference hole of the skeleton. Then, the pin hole position is photographed and calibrated a second time by the CCD vision system. After calibration, the carrier is locked and fixed to ensure that the coaxiality deviation between the pin hole and the PIN pin is not greater than 0.015mm.

[0030] Preferably, the bending angle, exposed length, position and appearance damage of the PIN pin are first detected by a vision system, with the angle tolerance controlled at ±1° and the length tolerance controlled at ±0.1mm.

[0031] Then, an online tensile testing agency conducts axial pull-out force tests on 5% of each batch of products. Products with a pull-out force lower than 40N are deemed unqualified and are automatically rejected.

[0032] Preferably, the opening of the barbed groove faces the insertion end of the PIN needle, the opposing sidewall of the groove forms an angle of 30° to 45° with the axial direction of the PIN needle, and the opposing sidewall forms a right angle of 90° with the axial direction of the PIN needle.

[0033] When the PIN is subjected to axial pull-out force, the right-angled sidewall and the plastic form a rigid barrier, while the sloping sidewall guides the plastic filling, forming a reverse anti-detachment mechanical interlocking structure.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] 1. This stepper motor pin insertion method, through the mechanical interlocking structure formed by the textured surface and plastic, increases the axial pull-out force of the pin by 3 to 5 times compared with the traditional smooth pin interference fit process. The measured average pull-out force can reach more than 60N, and the bonding force does not depend on the elasticity of the plastic. After high and low temperature cycles and long-term vibration, the attenuation rate is less than 10%, which can completely eliminate the electrical failure problem caused by pin movement and falling off. The average fault-free running time of the motor is increased by more than 2 times.

[0036] 2. This stepper motor pin insertion method effectively avoids defects such as misaligned pins, bent pins, and skeleton cracking through multi-level control including front-end multi-view visual inspection, segmented speed-changing pressing, and real-time pressure monitoring. The overall pin insertion yield can reach over 99.5%. The step-by-step pressing process reduces the accuracy requirements of a single pressing and has better adaptability to skeleton pin hole tolerances, indirectly reducing the precision cost of skeleton injection molding.

[0037] 3. This stepper motor pin insertion method is adaptable to square and round pins with cross-sections of 0.6mm to 1.2mm, and is compatible with various plastic materials such as PBT, PA, and LCP. It can upgrade the process without significantly modifying the existing automated production line structure. The entire process can be fully automated through the linkage of a vibratory feeder, servo mechanism, and vision system. The production cycle of a single station can reach 2 seconds per pin, and the production efficiency is more than 60% higher than that of the dispensing reinforcement process.

[0038] 4. In this stepper motor pin insertion method, the knurling process is only applied to the area where the pin root is embedded in the skeleton. The exposed welding section remains smooth and flat, which does not affect the subsequent enameled wire welding and winding process. The bending process of pre-bending and final bending avoids cracking of the pin body plating, which can improve the reliability of subsequent welding and the consistency of the weld points. Attached Figure Description

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0040] Figure 1 This is a schematic diagram of the process flow of the present invention.

[0041] Figure 2 This is a schematic diagram of the stepper motor pin insertion device of the present invention;

[0042] Figure 3 This is a top view of the stepper motor pins of the present invention;

[0043] Figure 4 This is a schematic diagram of the stepper motor cable protection box of the present invention;

[0044] Figure 5 This is a schematic diagram of the pins of the present invention. Detailed Implementation

[0045] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0046] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0047] In the description of this invention, terms such as greater than, less than, and exceeding are understood to exclude the stated number, while terms such as above, below, and within are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0048] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0049] Please see Figure 1-5 This invention provides a technical solution: a stepper motor pin insertion method, comprising the following steps performed sequentially:

[0050] S1. Needle feeding: After sorting and arranging the PIN needles one by one, feed them to the preset insertion position of the needle insertion station to complete the initial axial and circumferential positioning of the needle body.

[0051] S2. Visual inspection of pin positioning: The end face and side profile information of the PIN pin are obtained through a multi-view visual acquisition system and compared with the preset reference coordinates to confirm that the position and posture accuracy of the PIN pin meet the pin insertion threshold requirements.

[0052] S3. Initial pin insertion into the frame: The servo pressing mechanism is used to insert the PIN pins into the corresponding pin holes of the stepper motor frame at a uniform speed to complete the pre-positioning insertion. The insertion depth of the PIN pin is 30%~50% of the total depth of the pin hole. The length of the pin exposed on the frame surface is reserved for the texturing process.

[0053] S4. Engraving treatment: A symmetrical stamping mechanism is used to cold stamp and engrave the exposed PIN pin roots after initial insertion, forming multiple sets of circumferentially distributed anti-detachment textures on the pin body surface.

[0054] S5. Skeleton pin in place: Continue to press the PIN pin with the completed texturing treatment into the pin hole along the pin hole axis at a uniform speed until the PIN pin reaches the design limit position inside the pin hole. After holding the pressure for a set time, release the pressure so that the anti-loose texture and the plastic inner wall of the pin hole form a mechanical interlocking fit.

[0055] S6. Pin bending: The end of the PIN pin exposed outside the frame is first pre-bent and buffered, and then the final bend at a set angle is completed to form a standardized wiring pin.

[0056] Furthermore, in step S1, after the PIN needles are spirally sorted by the guide vibrating plate, they are transported to the material distribution station by the linear vibrating feeding track, and then pushed to the insertion fixture after being separated one by one by the material distribution blocks.

[0057] The insertion fixture uses a V-shaped positioning groove and an end face stop to hold the PIN pin. The clamping force is controlled at 5~10N, which ensures positioning accuracy and avoids damaging the tin plating layer on the surface of the pin, thus ensuring subsequent soldering performance.

[0058] Furthermore, in step S2, the multi-view vision acquisition system includes a top coaxial light camera and a side diffuse light camera. The top camera acquires the pin end face profile to identify the offset in the horizontal X / Y direction, and the side camera acquires the side profile of the pin body to identify the axial tilt angle.

[0059] When the position deviation exceeds ±0.02mm or the angle deviation exceeds ±0.5°, the servo fine-tuning platform drives the fixture to be inserted to complete the position correction. After correction, a second inspection is carried out. Only after passing the inspection can the needle insertion process be entered, thus eliminating the defects of misaligned or crooked needles from the source.

[0060] Furthermore, in step S3, the initial insertion pin adopts segmented variable speed press fitting: the front section travels quickly at 20~30mm / s to the position 0.5mm at the pin hole entrance, thereby improving processing efficiency;

[0061] The latter part is pressed into the target depth at a low and uniform speed of 10~15mm / s to avoid high-speed impact that could cause the needle body to bend or the skeleton hole to crack. During the pressing process, the pressing force is monitored in real time by a pressure sensor. When the pressing force exceeds the preset upper limit of 30N, it is determined that the needle hole is misaligned or the needle body is deformed, and the machine will automatically stop and alarm to avoid damage to the tooling and the product.

[0062] Furthermore, in step S4, the symmetrical stamping mechanism includes two sets of carbide pressure heads arranged opposite each other. The working surface of the pressure head is provided with raised teeth that match the texture, and the hardness is not less than HRC60 to ensure wear resistance during long-term stamping.

[0063] During stamping, the two sets of pressure heads are fed synchronously with a feed accuracy of ±0.01mm. One to two sets of barbed grooves are formed on each of the two opposite sides of the PIN needle. The groove cross-section is a right trapezoid with a depth of 0.05 to 0.15mm, an axial length of 1 to 2mm, and a tooth pitch of 0.3 to 0.6mm. Symmetrical stamping can ensure the needle body is under balanced force and avoid the needle body bending and shifting due to unilateral stamping.

[0064] Furthermore, in step S5, the insertion of the pin adopts a constant force pressing mode, with the pressing force set to 50~120N and the pressing speed to 5~10mm / s;

[0065] Low-speed compression ensures that the plastic material has enough time to undergo plastic deformation, avoiding cracking caused by high-speed extrusion.

[0066] After pressing to the target depth, hold the pressure for 0.3~0.8s to allow the plastic material on the inner wall of the pinhole to fully fill the grooves of the anti-detachment texture. After holding the pressure, the press head retracts at a uniform speed of 5mm / s to prevent the press head from sticking to the needle and causing the needle to spring back and shift.

[0067] Furthermore, in step S6, the pre-bending buffer uses an arc pusher to bend the end of the PIN pin by 30°~45° to release the internal stress of the pin body. The final bending uses a right-angle bending die to bend the pin to 90°. The bending radius is 0.5~1 times the side length of the PIN pin cross-section to avoid the pin body breaking or the plating peeling off due to the right-angle hard bending.

[0068] During the bending process, the base of the PIN needle is supported by a support pad. The support pad fits tightly against the surface of the skeleton, offsetting the radial force generated by bending and preventing the needle base from loosening due to the bending impact.

[0069] Furthermore, before step S3, there is also a skeleton loading and calibration step: the stepper motor skeleton is sorted and transported to the positioning carrier of the pin insertion fixture via the skeleton vibration plate. The elastic positioning pin is inserted into the reference hole of the skeleton to complete the initial positioning. Then, the CCD vision system performs secondary photo calibration on the pin hole position. After calibration, the carrier is locked and fixed by the cylinder to ensure that the coaxiality deviation between the pin hole and the PIN pin is no more than 0.015mm, which provides a basis for high-precision insertion.

[0070] Furthermore, after step S6, there is also a finished product full inspection step: first, the bending angle, exposed length, position and appearance damage of the PIN pin are detected by a vision system, with the angle tolerance controlled at ±1° and the length tolerance controlled at ±0.1mm;

[0071] Then, an online tensile testing agency conducts axial pull-out force tests on 5% of each batch of products. Products with a pull-out force lower than 40N are deemed unqualified and are automatically rejected to ensure the consistency of products leaving the factory.

[0072] Furthermore, the opening of the barbed groove faces the insertion end of the PIN needle, the opposing sidewall of the groove forms an angle of 30°~45° with the axial direction of the PIN needle, and the opposing sidewall forms a right angle of 90° with the axial direction of the PIN needle.

[0073] During the pressing process, the inclined sidewall guides the plastic to flow smoothly into the groove. When the PIN needle is subjected to axial pull-out force, the right-angle sidewall and the plastic form a rigid barrier, which greatly increases the pull-out resistance and forms a reliable reverse anti-detachment mechanical interlock structure.

[0074] The present invention will be further described in detail below with reference to two specific embodiments. The embodiments are only used to explain the present invention and do not limit the scope of protection of the present invention.

[0075] Example 1:

[0076] This embodiment is applied to the production of pins for the wire guard box frame of a small stepper motor. The object being processed is a square tin-plated copper PIN pin with a cross-sectional dimension of 0.8mm × 0.8mm and a total length of 8mm.

[0077] The skeleton is made of glass fiber reinforced PBT plastic, with a total depth of 6mm and a hole diameter of 0.75mm for each pin.

[0078] The specific process steps are as follows:

[0079] The stepper motor frames are sorted and arranged by the frame vibratory feeder and fall one by one into the positioning carrier of the circulating tooling.

[0080] After the elastic positioning pin is inserted into the reference hole on the side of the framework to complete initial positioning, the carrier is transferred to the calibration station, where the top CCD camera captures and identifies the pin hole position, drives the carrier to perform fine-tuning compensation after calculating the position deviation, and locks the carrier with an air cylinder after the compensation is completed. At this time, the coaxiality deviation between the axis of the pin hole and the axis of the pin insertion pressure head is controlled within 0.012 mm.

[0081] Feeding and positioning of PIN needles: after PIN needles enter the straight-line vibration plate, they undergo sorting through the spiral track and posture screening, and correctly oriented needles are conveyed to the distributing station along the linear vibration track;

[0082] The distributing stop block separates the continuously conveyed needles one by one, the pushing mechanism pushes a single PIN needle into the V-shaped positioning groove of the fixture to be inserted, the end stop block abuts against the needle tail to complete axial positioning, and the fixture clamps the needle with a clamping force of 8 N to ensure that the needle does not deflect circumferentially;

[0083] Then the fixture to be inserted moves to directly above the pin insertion station to complete needle feeding and positioning.

[0084] Visual inspection of needle in place: the coaxial light camera at the top and the diffuse light camera at the side of the needle feeding and visual inspection station capture images simultaneously to extract the center coordinates of the PIN needle end face and the side profile;

[0085] The system compares the detection value with the preset reference, and in this embodiment, the threshold is set as position deviation ±0.02 mm and angle deviation ±0.5°;

[0086] If the deviation is within the threshold, it is determined as qualified;

[0087] If the deviation exceeds the threshold, the servo fine-tuning platform drives the fixture to be inserted to perform X / Y direction and angle correction, and a re-inspection is performed after correction. If it is qualified, the process proceeds to the next step; if it is unqualified, the PIN needle is determined as defective and removed.

[0088] Initial pin insertion for framework: the servo press-fitting mechanism of the initial pin insertion station drives the pressure head to move downward, adopting a segmented variable speed mode: first moving downward rapidly at 25 mm / s to a position 0.5 mm above the pin hole inlet, then pressing into the pin hole at a constant low speed of 12 mm / s, with a pressing depth of 2.4 mm (which accounts for 40% of the total depth), thus completing the pre-positioning insertion.

[0089] During the press-fitting process, the pressure sensor collects the pressing force in real time. The normal pressing force is 10~20 N. If the pressure exceeds 30 N, the machine will stop immediately and trigger an alarm to check for pin hole deviation or needle deformation;

[0090] After press-fitting is completed, the length of the PIN needle exposed on the upper surface of the framework is 3.2 mm, wherein the 2 mm section close to the framework surface is the knurling processing area.

[0091] For the texturing process, the tooling is transferred to the texturing station. Two sets of symmetrically arranged carbide indenters are aligned with the processing area at the root of the PIN needle and feed synchronously into the needle body. The feed depth is 0.1mm and the feed speed is 0.5mm / s.

[0092] After stamping, a set of barbed grooves is formed on each of the two opposite sides of the PIN pin. The groove has an axial length of 1.5mm and contains 3 teeth with a tooth pitch of 0.5mm.

[0093] The trench cross-section is a right trapezoid, with the inclined surface on the inlet side forming a 40° angle with the axial direction, and the back-inlet side being a right-angled surface perpendicular to the axial direction;

[0094] After the stamping and holding pressure for 0.2 seconds, the pressure head retracts synchronously. Symmetrical stamping ensures that the needle body is subjected to uniform force and has no bending deformation.

[0095] Once the skeleton pin is in place, the tooling is transferred to the pin placement station, and the pressing mechanism descends again, using a constant force pressing mode. The pressing force is set to 80N and the pressing speed to 8mm / s, pressing the PIN pin in for another 3.6mm until the pin tail contacts the bottom of the pin hole, with a total insertion depth of 6mm.

[0096] After being pressed into place, the pressure is held for 0.5 seconds to allow the compressed PBT plastic to fully flow plastically and fill the internal space of the barbed groove, forming a tight mechanical interlocking structure.

[0097] After the pressure holding period ends, the pressure head retracts at a constant speed of 5mm / s to prevent the needle from springing back.

[0098] During the bending process, the tooling is transferred to the bending station, where the support pad first extends to fit the upper surface of the skeleton and abuts against the root of the PIN pin.

[0099] Then, the arc-shaped pusher is fed horizontally to pre-bend the exposed end of the PIN pin by 40° to release stress.

[0100] Finally, the right-angle bending die moves downwards, bending the pin to 90°. The bending position is 2mm away from the skeleton surface, and the bending radius is 0.4mm.

[0101] After bending, the mold and pad block retract sequentially to avoid pulling the needle body during mold removal.

[0102] Finished product inspection: The finished product is transferred to the inspection station along with the tooling. The vision system performs a full inspection of the bending angle, exposed length and position of the pins. In this embodiment, the pass standard is 90°±1° for the angle and 2±0.1mm for the exposed length.

[0103] At the same time, 5 pieces are randomly selected from every 100 pieces for tensile testing, and the axial pull-out force is required to be no less than 50N.

[0104] Actual measurements show that the average axial pull-out force of the product in this embodiment is 68N, which is much higher than the 21N of the traditional process. After 1000 cycles of temperature cycling from -40℃ to 125℃, the pull-out force still remains above 61N, with a decay rate of only 10.3%. The overall production yield reaches 99.6%, and the cycle time per station is 1.8s / needle.

[0105] Example 2:

[0106] This embodiment is applied to the production of pins for medium-sized stepper motor frames. The processing object is a round nickel-plated copper PIN pin with a diameter of 1.0 mm and a total length of 10 mm. The frame material is high-temperature resistant LCP plastic, with a total pin hole depth of 7 mm and a hole diameter of 0.95 mm.

[0107] The process steps in this embodiment are basically the same as those in Embodiment 1, with the core parameters adjusted as follows:

[0108] The initial insertion depth is 3.5mm, which is 50% of the total depth, and the exposed section length is 3.5mm.

[0109] The texturing process uses four sets of pressure heads distributed 90° circumferentially to form four sets of barbed grooves on the needle body surface. The groove depth is 0.12mm and the axial length is 2mm.

[0110] The insertion force is set to 110N and the holding time is 0.6s.

[0111] The final bending angle of the bent needle is 90°, the bending position is 2.5mm away from the surface of the skeleton, and the bending radius is 0.5mm.

[0112] Actual measurements show that the average axial pull-out force of the product in this embodiment can reach 85N. After 500 hours of random vibration testing, there was no loosening of the needle body, which meets the requirements for the use of high-reliability industrial-grade stepper motors.

[0113] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for inserting pins into a stepper motor, characterized in that, This includes the following steps performed sequentially: S1. Needle feeding: After sorting and arranging the PIN needles one by one, feed them to the preset insertion position of the needle insertion station to complete the initial axial and circumferential positioning of the needle body. S2. Visual inspection of pin positioning: The end face and side profile information of the PIN pin are obtained through a multi-view visual acquisition system and compared with the preset reference coordinates to confirm that the position and posture accuracy of the PIN pin meet the pin insertion threshold requirements. S3. Initial pin insertion into the frame: The servo pressing mechanism is used to insert the PIN pins into the corresponding pin holes of the stepper motor frame at a uniform speed to complete the pre-positioning insertion. The insertion depth of the PIN pin is 30%~50% of the total depth of the pin hole. The length of the pin exposed on the frame surface is reserved for the texturing process. S4. Engraving treatment: A symmetrical stamping mechanism is used to cold stamp and engrave the exposed PIN pin roots after initial insertion, forming multiple sets of circumferentially distributed anti-detachment textures on the pin body surface. S5. Skeleton pin in place: Continue to press the PIN pin with the completed texturing treatment into the pin hole along the pin hole axis at a uniform speed until the PIN pin reaches the design limit position inside the pin hole. After holding the pressure for a set time, release the pressure so that the anti-loose texture and the plastic inner wall of the pin hole form a mechanical interlocking fit. S6. Pin bending: The end of the PIN pin exposed outside the frame is first pre-bent and buffered, and then the final bend at a set angle is completed to form a standardized wiring pin.

2. The stepper motor pin insertion method according to claim 1, characterized in that: The PIN needles mentioned in step S1 are spirally sorted by the guide vibrating plate and then conveyed to the sorting station by the straight vibrating feeding track. They are then separated one by one by the sorting blocks and pushed to the clamp to be inserted. The clamping fixture uses a V-shaped positioning groove and an end face stop to hold the PIN pin. The clamping force is controlled at 5~10N, which ensures positioning accuracy and avoids damaging the pin body plating.

3. The stepper motor pin insertion method according to claim 1, characterized in that: The multi-view vision acquisition system described in step S2 includes a top coaxial light camera and a side diffuse light camera. The top camera captures the pin end face profile to identify the horizontal offset, and the side camera captures the side profile of the pin body to identify the axial tilt angle. When the position deviation exceeds ±0.02mm or the angle deviation exceeds ±0.5°, the servo fine-tuning platform drives the fixture to be inserted to complete the position correction. After correction, a second inspection is carried out. Only after passing the inspection can the pin insertion process begin.

4. The stepper motor pin insertion method according to claim 1, characterized in that: The initial insertion of the pin in step S3 adopts segmented variable speed pressing: the front section travels quickly at 20~30mm / s to the position 0.5mm at the pin hole entrance, and the rear section presses in at a low speed of 10~15mm / s to the target depth. During the pressing process, the pressing force is monitored in real time by a pressure sensor. When the pressing force exceeds the preset upper limit of 30N, it is determined that the needle hole is misaligned or the needle body is deformed, and the machine will automatically stop and alarm.

5. A stepper motor pin insertion method according to claim 1, characterized in that: The symmetrical stamping mechanism described in step S4 includes two sets of carbide pressure heads arranged opposite each other, and the working surface of the pressure head is provided with raised teeth that match the texture. During stamping, the two sets of pressure heads are fed synchronously, with a feed accuracy controlled at ±0.01mm. One to two sets of barbed grooves are formed on each of the two opposite sides of the PIN pin. The groove cross-section is a right trapezoid with a depth of 0.05 to 0.15mm, an axial length of 1 to 2mm, and a tooth pitch of 0.3 to 0.6mm.

6. The stepper motor pin insertion method according to claim 1, characterized in that: In step S5, the insertion of the pin is carried out using a constant force pressing mode, with the pressing force set to 50~120N and the pressing speed to 5~10mm / s. After pressing to the target depth, hold the pressure for 0.3~0.8s to allow the plastic material on the inner wall of the pinhole to undergo sufficient plastic deformation and fill the groove of the anti-detachment texture. After holding the pressure, the press head retracts at a constant speed to avoid the pin rebounding.

7. A stepper motor pin insertion method according to claim 1, characterized in that: In step S6, the pre-bending buffer uses an arc pusher to bend the end of the PIN pin by 30° to 45°, and the final bending uses a right-angle bending die to bend the pin to 90°. The bending radius is 0.5 to 1 times the side length of the PIN pin cross-section. During the bending process, the base of the PIN needle is supported by a support pad. The support pad fits against the surface of the skeleton, offsetting the radial force of bending and preventing the base of the needle from loosening.

8. A stepper motor pin insertion method according to claim 1, characterized in that: Before step S3, there is also a skeleton loading and calibration step: the stepper motor skeleton is sorted and transported to the positioning carrier of the pin insertion fixture via the skeleton vibration plate. The elastic positioning pin is inserted into the reference hole of the skeleton to complete the initial positioning. Then, the CCD vision system takes a second photo to calibrate the pin hole position. After calibration, the carrier is locked and fixed to ensure that the coaxiality deviation between the pin hole and the PIN pin is not greater than 0.015mm.

9. A stepper motor pin insertion method according to claim 1, characterized in that: The step S6 is followed by a finished product full inspection step: First, the bending angle, exposed length, position and appearance damage of the PIN pin are detected by a vision system. The angle tolerance is controlled at ±1° and the length tolerance is controlled at ±0.1mm. Then, an online tensile testing agency conducts axial pull-out force tests on 5% of each batch of products. Products with a pull-out force lower than 40N are deemed unqualified and are automatically rejected.

10. A stepper motor pin insertion method according to claim 1, characterized in that: The opening of the barbed groove faces the insertion end of the PIN needle. The opposing sidewall of the groove forms an angle of 30° to 45° with the axial direction of the PIN needle, and the opposing sidewall forms a right angle of 90° with the axial direction of the PIN needle. When the PIN is subjected to axial pull-out force, the right-angled sidewall and the plastic form a rigid barrier, while the sloping sidewall guides the plastic filling, forming a reverse anti-detachment mechanical interlocking structure.

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