Micro motor rotating shaft grinding device and grinding method thereof

Abstract

The invention relates to a micro motor rotating shaft polishing device and a polishing method thereof, and belongs to the technical field of micro motor polishing. An automatic tensioning assembly comprises a first gear fixed to a supporting part, a hinge block connected to the supporting part in a swinging mode, a second gear arranged on the hinge block and an elastic piece enabling the hinge block to be offset towards the first gear; the first gear and the second gear are meshed with each other, a gap used for clamping the other end of the flexible grinding part is formed in the meshing position, and when the flexible grinding belt is loosened due to abrasion or extension, the elastic piece can drive the hinge block to swing, so that the second gear moves towards the first gear, and the loosened grinding belt is automatically tightened and pulled into the meshing gap of the gears; therefore, the length change of the grinding belt is compensated in real time, the working tension is kept constant, the stability of the contact pressure between the grinding belt and the rotating shaft in the grinding process is ensured, the problems of high and low grinding efficiency, quality fluctuation and slipping caused by pressure attenuation are avoided, and the grinding consistency and reliability are improved.

Description

Technical Field

[0001] This invention belongs to the field of micro motor polishing technology, specifically relating to a micro motor shaft polishing device and polishing method. Background Technology

[0002] In the precision manufacturing of micro motors, the grinding, polishing and deburring processes of the shaft are crucial to the surface quality. Currently, for grinding such small shafts, apart from high-cost CNC equipment, the method of wrapping sandpaper or flexible grinding belt around the shaft and driving the shaft to rotate or making the grinding belt reciprocate is mostly used. In order to ensure the grinding effect, these methods usually require fixing or pre-tensioning both ends of the grinding belt to ensure that it has sufficient initial contact pressure and friction with the shaft surface.

[0003] However, existing technologies that rely on fixed pretension have a significant inherent drawback. During the grinding process, the grinding belt, as a consumable, inevitably undergoes two changes due to continuous friction with the shaft: firstly, it experiences slight wear, resulting in thinner belts and an increased effective length; secondly, it may undergo plastic elongation under continuous tension. These minute length changes directly lead to the gradual loosening of the grinding belt, causing a decrease in the actual pressure exerted on the shaft surface by its working section. This pressure instability causes a series of problems: firstly, within a single work cycle, grinding efficiency is high at the beginning and low at the end, resulting in uneven effects; secondly, the processing quality fluctuates between different workpieces due to the inability to guarantee consistent initial pressure. Even worse, excessive loosening may cause slippage between the grinding belt and the shaft, not only completely losing the grinding effect but also potentially damaging the workpiece due to abnormal friction. Therefore, existing technologies lack an effective mechanism that can maintain a constant tension of the grinding belt in real time and automatically throughout the entire operation. To address this, a micro-motor shaft grinding device and its grinding method are proposed. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, this invention provides a micro motor shaft grinding device and grinding method, which solves the problem that existing micro motor shaft grinding devices cannot automatically maintain a constant tension of the grinding belt during the grinding process, resulting in unstable grinding pressure, which in turn causes uneven grinding efficiency, quality fluctuations, and slippage.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A micro motor shaft grinding device includes a support part, a flexible grinding part, a tightening wheel part, an automatic tensioning assembly, and a workpiece positioning part. The tightening wheel part is disposed on the support part. One end of the flexible grinding part is retractably fixed to the tightening wheel part. The automatic tensioning assembly is disposed on the support part and acts on the other end of the flexible grinding part. The workpiece positioning part is used to fix the micro motor and position its shaft below the flexible grinding part. The automatic tensioning assembly includes a first gear fixed to the support part, a hinge block oscillatingly connected to the support part, a second gear disposed on the hinge block, and an elastic element that biases the hinge block toward the first gear. The first gear and the second gear mesh with each other and form a gap at their meshing point for clamping the other end of the flexible grinding part. The elastic element compensates for the length change of the flexible grinding part caused by wear or elongation by driving the hinge block to oscillate, thereby maintaining a constant working tension of the grinding belt.

[0007] As a further embodiment of the present invention, the flexible polishing part includes a flexible polishing belt and a plurality of limiting blocks for guiding the flexible polishing belt. The plurality of limiting blocks are disposed on the support part, and the flexible polishing belt is wound around the plurality of limiting blocks in sequence.

[0008] As a further embodiment of the present invention, the number of the plurality of limiting blocks is seven. Four limiting blocks are provided on the support portion above the micro motor, and the four limiting blocks are arranged in a trapezoidal shape. Three limiting blocks are provided on the support portion near the tightening wheel portion, and the three limiting blocks are arranged in a triangular shape.

[0009] As a further aspect of the present invention, the ratio of the width of the flexible grinding belt to the tooth width of the first gear or the second gear is 0.7 to 0.9.

[0010] As a further embodiment of the present invention, the first gear and the second gear have the same diameter and number of teeth, and the clamping gap formed between the first gear and the second gear at the meshing point is 1.1 to 1.3 times the thickness of the flexible grinding belt.

[0011] As a further embodiment of the present invention, the elastic element is a helical spring, one end of the helical spring is mounted on the support via a rotating block, and the other end of the helical spring is provided with an arc-shaped block, the inner wall of which engages with one end of the hinge block.

[0012] As a further embodiment of the present invention, the rotating block and the support are rotatably connected, the inner wall of the arc-shaped block is provided with a silicone block, and the contact surface of the silicone block is provided with a plurality of protrusions, the height of the plurality of protrusions gradually decreasing from the inside of the opening of the arc-shaped block to the outside of the opening.

[0013] A method for grinding a micro motor shaft includes the following steps:

[0014] S1: Fix the micro motor to be polished to the workpiece positioning part, so that the rotating shaft of the micro motor is accurately positioned below the flexible polishing belt;

[0015] S2: Based on the characteristics of the area to be ground on the shaft of the micro motor, the grinding path is divided into a rough grinding area, a fine grinding area, and a transition area.

[0016] S3: By adjusting the initial tension of the helical spring, the initial working tension of the flexible grinding belt is set, so that the micro motor shaft rotates at the preset speed, while tightening the wheel and releasing an appropriate length of grinding belt.

[0017] S4: First, the rough grinding zone is processed. By adjusting the initial tension of the spiral spring and controlling the tightening wheel, the flexible grinding belt applies greater contact pressure, and then drives the shaft to rotate at high speed to quickly remove the roughness and burrs on the shaft surface. Then, the transition zone is processed, and the shaft speed is gradually reduced to reduce the contact pressure with the shaft and make the contact force decay smoothly. Then, the fine grinding zone is processed, and the shaft speed and contact pressure of the micro motor are reduced again. Under the constant tension maintained by the automatic tensioning component, the grinding belt performs fine processing on the shaft surface with gentle and uniform pressure, thereby obtaining a smooth and consistent final surface.

[0018] S5: After the micro motor shaft has finished grinding all three areas, stop running, loosen the workpiece positioning part, and take out the micro motor that has finished grinding.

[0019] As a further aspect of the present invention, in step S1, the length of the area to be polished on the shaft of the micro motor is equal to the width of the flexible polishing belt.

[0020] As a further aspect of the present invention, when the flexible grinding belt becomes loose due to wear or elongation, the helical spring drives the hinge block and the second gear to swing, automatically tightening the loose grinding belt and pulling it into the meshing gap of the gear, so as to maintain a constant working tension.

[0021] The beneficial effects of this invention are as follows:

[0022] This invention employs an automatic tensioning assembly, comprising a first gear fixed to a support, a hinge block oscillatingly connected to the support, a second gear mounted on the hinge block, and an elastic element that biases the hinge block toward the first gear. The first and second gears mesh with each other, forming a gap at the meshing point for clamping the other end of the flexible grinding section. When the flexible grinding belt loosens due to wear or elongation, the elastic element drives the hinge block to oscillate, causing the second gear to move toward the first gear, automatically tightening the loosened grinding belt and pulling it into the meshing gap of the gears. This compensates for changes in the length of the grinding belt in real time, maintaining a constant working tension. This design ensures stable contact pressure between the grinding belt and the rotating shaft during grinding, avoiding grinding efficiency fluctuations, quality variations, and slippage caused by pressure decay, thus improving the consistency and reliability of grinding. Attached Figure Description

[0023] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0024] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 This is a schematic diagram of the automatic tensioning component structure of the present invention;

[0026] Figure 3 This is a schematic diagram of the elastic element structure of the present invention;

[0027] Figure 4 This is a flowchart of the micro motor shaft grinding method of the present invention.

[0028] Explanation of key component symbols:

[0029] In the diagram: 1. Support section; 2. Flexible grinding section; 21. Flexible grinding belt; 22. Limiting block; 3. Tensioning wheel section; 4. Automatic tensioning assembly; 41. First gear; 42. Hinge block; 43. Second gear; 44. Elastic element; 5. Workpiece positioning section; 6. Micro motor; 7. Rotating block; 8. Arc block. Detailed Implementation

[0030] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0031] Please see Figure 1 - Figure 4As shown, this embodiment provides a micro motor 6 shaft grinding device, including a support part 1, a flexible grinding part 2, a tightening wheel part 3, an automatic tensioning component 4, and a workpiece positioning part 5. The tightening wheel part 3 is disposed on the support part 1. One end of the flexible grinding part 2 is retractably fixed to the tightening wheel part 3. The automatic tensioning component 4 is disposed on the support part 1 and acts on the other end of the flexible grinding part 2. The workpiece positioning part 5 is used to fix the micro motor 6 and position its shaft below the flexible grinding part 2. The automatic tensioning component 4 includes a first gear 41 fixed to the support part 1, a hinge block 42 oscillatingly connected to the support part 1, a second gear 43 disposed on the hinge block 42, and an elastic element 44 that biases the hinge block 42 toward the first gear 41. The first gear 41 and the second gear 43 mesh with each other and form a gap at their meshing point for clamping the other end of the flexible grinding part 2. The elastic element 44 compensates for the length change of the flexible grinding part 2 caused by wear or elongation by driving the hinge block 42 to oscillate, thereby maintaining a constant working tension of the grinding belt.

[0032] It should be noted that the support part 1 is the support platform for the micro motor 6 shaft grinding device, and the tensioning wheel part 3 is the tensioning wheel set on the support part 1. The core advantage of the automatic tensioning component 4 is that it can automatically maintain the constant tension of the flexible grinding belt 21. This means that the pressure of the flexible grinding belt 21 on the shaft surface remains consistent throughout the grinding process, thereby ensuring the uniformity and consistency of the grinding effect and avoiding the uneven grinding and quality fluctuation problems caused by pressure attenuation in traditional methods. The structure is compact, using meshing gears and swing hinge block 42 as clamping and tensioning mechanisms. The bias force provided by the elastic element 44 can sense minute length changes and is controlled by the hinge block 4. The small oscillation of the 2nd gear reacts immediately, with a fast response speed and high control precision. When the grinding belt is pulled in the tightening direction, the meshing action of the gears will tightly bite the flexible grinding belt 21 to prevent it from slipping back. The gear teeth can evenly distribute the pressure on the width of the flexible grinding belt 21, avoiding stress concentration that could cause the grinding belt to tear. The oscillation of the hinge block 42 provides an arc-shaped displacement space. When the grinding belt becomes longer, the elastic element 44 pushes the hinge block 42 to swing towards the first gear 41. This action solves the problem of the loosened part of the length. The hinge block 42 acts as a lever, which can convert the small deformation of the elastic element 44 into sufficient displacement at the gear gap to tighten the grinding belt, thus amplifying the adjustment effect.

[0033] Currently, in precision grinding of a micro motor with 6 rotating shafts, existing technologies mostly use pre-tensioned flexible grinding belts 21 for operation. However, the grinding belt will increase in length and gradually loosen due to wear and plastic elongation during the process, resulting in a decrease in the pressure acting on the rotating shaft, causing uneven grinding efficiency, fluctuations in processing quality, and even slippage and damage to the workpiece. There is a lack of an effective mechanism to maintain constant tension throughout the entire operation.

[0034] To address the aforementioned issues, this embodiment incorporates an automatic tensioning assembly 4. This assembly includes a first gear 41 fixed to the support 1, a hinge block 42 oscillatingly connected to the support 1, a second gear 43 mounted on the hinge block 42, and an elastic element 44 that biases the hinge block 42 toward the first gear 41. The first gear 41 and the second gear 43 mesh with each other, forming a gap at the meshing point for clamping the other end of the flexible grinding section 2. When the flexible grinding belt 21 becomes loose due to wear or elongation, the elastic element 44 drives the hinge block 42 to oscillate, causing the second gear 43 to move toward the first gear 41, automatically tightening the loosened grinding belt and pulling it into the meshing gap of the gears. This compensates for changes in the length of the grinding belt in real time, maintaining a constant working tension. This design ensures stable contact pressure between the grinding belt and the rotating shaft during the grinding process, avoiding grinding efficiency fluctuations, quality variations, and slippage caused by pressure decay, thus improving the consistency and reliability of the grinding process.

[0035] Because the flexible grinding belt 21 is flexible, it does not have the ability to maintain its shape and is easily deformed and deviated under stress. During the grinding process, the flexible grinding belt 21 is not only subjected to the longitudinal tension provided by the automatic tensioning component 4, but also to the tangential friction force from the rotation of the shaft, its own inertial force, and possible lateral forces. This is a complex multi-directional force system without guidance and constraint, and its motion trajectory is unpredictable. In order to ensure that the flexible grinding belt 21 can connect with the shaft of the micro motor 6 in a preset, stable path and posture, This allows for a controllable and precise polishing process. In one embodiment, the flexible polishing section 2 includes a flexible polishing belt 21 and several limiting blocks 22 for guiding the flexible polishing belt 21. The limiting blocks 22 are disposed on the support section 1. The flexible polishing belt 21 is wound around the limiting blocks 22 in sequence. Wrapping the flexible polishing belt 21 around the limiting blocks 22 in sequence is equivalent to laying a track for it. The limiting blocks 22 forcibly define the path that the polishing belt must take, fundamentally eliminating the possibility of deviation and large vibration.

[0036] Following the above embodiment, there are seven limiting blocks 22. Four limiting blocks 22 are provided on the support part 1 above the micro motor 6. The four limiting blocks 22 are arranged in a trapezoidal shape. After the flexible grinding belt 21 is wound around the four trapezoidal limiting blocks 22, it also forms a trapezoidal shape. The shaft of the micro motor 6 is located below the trapezoidal grinding belt. Figure 1As shown, when the rotating shaft presses against the trapezoidal flexible polishing belt 21 from below, under tension, the flexible polishing belt 21 will naturally tend to contract towards the center line of the trapezoid. This will automatically constrain and guide the rotating shaft to the center path of the trapezoid. This self-centering effect ensures that the rotating shaft can always remain on a stable straight line during polishing, effectively preventing the rotating shaft from sliding or deviating relative to the polishing belt. In addition, this design allows the flexible polishing belt 21 to slightly wrap around the rotating shaft, forming a flexible surface contact area with a certain width. Compared with ideal line contact, this surface contact makes the contact pressure distribution more uniform, avoiding excessive stress concentration, thereby obtaining a more consistent surface finish. To improve the grinding effect and reduce localized rapid wear on the grinding belt, three limiting blocks 22 are provided on the support part 1 near the tensioning wheel 3. The three limiting blocks 22 are arranged in a triangle. The main function of these three limiting blocks 22 near the tensioning wheel 3 is to change the direction of power transmission and stabilize the system. They smoothly turn and transmit the longitudinal tension from the automatic tensioning component 4 and the tensioning wheel 3 to the trapezoidal area where the four limiting blocks 22 are arranged in a trapezoidal shape. Since a triangle is the most stable structure, the triangular layout formed by these three limiting blocks 22 ensures the stability of the grinding belt path in the non-working section, prevents vibration or deviation caused by drastic changes in direction, and provides a solid foundation for precise control in the working section.

[0037] To prevent the flexible abrasive belt 21 from mismatching with the gear width, which could lead to lateral slippage during operation, causing it to slide out of the gear's clamping area, or its edge to rub against the gear's side, resulting in jamming or even tearing, in one embodiment, the ratio of the width of the flexible abrasive belt 21 to the tooth width of the first gear 41 or the second gear 43 is 0.7. The width of the flexible grinding belt 21 is approximately 0.9 mm, less than the tooth width of a single gear, but still 70% to 90% of it. This ensures that there is always sufficient gear tooth surface on both sides of the flexible grinding belt 21 to provide lateral constraint, preventing lateral deviation. If the grinding belt and the gear were the same width, any slight alignment error would cause rigid friction and wear between its edge and the gear end face. A width margin of 10% to 30% provides necessary installation and operational tolerance, ensuring smooth operation. Furthermore, the diameter and number of teeth of the first gear 41 and the second gear 43 are the same. When identical gears mesh, their pitch circle linear velocities are exactly the same. This ensures that the traction on both sides of the grinding belt is absolutely synchronous, preventing twisting, shearing, or wrinkling of the grinding belt due to speed differences. The identical gears can form a parallel and uniform clamping gap in the meshing area, which is a prerequisite for achieving uniform pressure distribution. The clamping gap formed by the first gear 41 and the second gear 43 at the meshing point is 1.1 to 1 / 3 of the thickness of the flexible grinding belt 21. The 1.3 times gap here, which is 1.1 to 1.3 times, is an interference fit. When the grinding belt is pulled into this slightly narrow gap, the gear teeth will slightly embed or press into the grinding belt substrate, generating huge static friction force to achieve self-locking clamping and prevent it from slipping back under working tension. The gap is not small enough to completely crush the grinding belt.

[0038] It is worth mentioning that, since the automatic tensioning component 4 is a dynamic, non-linear motion, and the oscillation of the hinge block 42 is an arc motion, while ideally the spring should be stretched or compressed in a straight line, this mismatch in motion trajectory will inevitably generate lateral force. Furthermore, friction exists between any two contacting parts with relative motion. In tensioning systems requiring high sensitivity to respond to minute length changes, friction is a major issue. Moreover, the vibration and tension changes during the grinding process are continuous, meaning that the elastic element 44 and its connecting mechanism are always in a dynamic, impulsive state. Working in an environment requiring high impact resistance necessitates higher demands on the structure's fatigue and impact resistance. In one embodiment, the elastic element 44 is a helical spring. One end of the helical spring is mounted on the support 1 via a rotating block 7, and the other end is fitted with an arc-shaped block 8. The inner wall of the arc-shaped block 8 engages with one end of the hinge block 42. The rotating block 7 is rotatably connected to the support 1. A silicone block is provided on the inner wall of the arc-shaped block 8, and several protrusions are provided on the contact surface of the silicone block. The height of these protrusions gradually decreases from the inside of the opening of the arc-shaped block 8 towards the outside. 7, serving as the connection point between the helical spring and the support 1, features a pivotal connection design that is crucial. This design allows the helical spring to rotate slightly under load, releasing the torque exerted on it by the swinging of the hinge block 42. This ensures the helical spring primarily bears only the axial force of pure tension, significantly extending its lifespan. The arc-shaped block 8 is installed at the other end of the helical spring, its inner wall engaging with one end of the hinge block 42. The arc-shaped inner wall provides a precisely matched track for the swinging of the hinge block 42, allowing it to interact with the helical spring during swinging. The contact point of the spring can move smoothly along the arc surface instead of scraping hard at a fixed point, thus transforming harmful sliding friction into more controllable guiding contact. The silicone block, as a flexible medium, is placed between the arc block 8 and the hinge block 42. On the one hand, it can effectively absorb vibration and impact energy, reduce impact noise and wear between metal parts. In addition, the purpose of the silicone block here is to moderately and controllably increase the friction force, but this friction force is used to provide damping to prevent the hinge block 42 from vibrating or shaking at high frequency when the tension changes abruptly, making the tensioning action smoother and gentler.

[0039] The height of the protrusion gradually decreases from the inside of the opening of the arc-shaped block 8 to the outside of the opening. When the hinge block 42 is inside the opening, it presses on the larger protrusion, and the silicone block undergoes a large deformation, thereby providing a large static friction force and damping force. This prevents the hinge block 42 from vibrating or shaking during sudden tension changes. When a large tightening is required, the hinge block 42 swings outward, and the contact protrusion becomes lower and lower. The deformation of the silicone block decreases accordingly, and the resulting sliding friction force is also significantly reduced. Low damping means that the elastic element 44 can drive the hinge block 42 to complete a large stroke swing with less force and faster speed. This ensures that the system responds very sensitively and quickly to sudden relaxation of the grinding belt, can immediately compensate for length changes, and avoids a brief period of insufficient grinding pressure due to response lag. The change from high protrusion to low protrusion is gradual rather than abrupt, so that the damping force experienced by the hinge block 42 during the swing is continuous and smooth, avoiding jamming.

[0040] A method for grinding a 6-axis micro motor includes the following steps:

[0041] S1: Fix the micro motor 6 to be polished to the workpiece positioning part 5, so that the rotating shaft of the micro motor 6 is accurately positioned below the flexible polishing belt 21; by fixing the rotating shaft precisely at the preset position below the polishing belt through the workpiece positioning part 5, it is ensured that each workpiece to be processed has the same initial conditions.

[0042] S2: Based on the characteristics of the area to be polished on the shaft of the micro motor 6, the polishing path is divided into a rough polishing area, a fine polishing area, and a transition area.

[0043] S3: By adjusting the initial tension of the helical spring, the initial working tension of the flexible grinding belt 21 is set, so that the shaft of the micro motor 6 rotates at the preset speed. At the same time, the tightening wheel 3 releases an appropriate length of grinding belt. Adjusting the initial tension of the helical spring and setting the initial tension of the grinding belt, so that the shaft rotates at the preset speed and the tightening wheel 3 releases an appropriate length of grinding belt, ensures that the automatic tensioning component 4 is within its effective working stroke range.

[0044] S4: First, the rough grinding zone is treated. By adjusting the initial tension of the helical spring and controlling the tightening wheel, the flexible grinding belt 21 is subjected to greater contact pressure. Then, the shaft is driven to rotate at high speed to quickly remove the roughness and burrs on the shaft surface. Next, the transition zone is treated, and the shaft speed is gradually reduced to decrease the shaft rotation speed in a stepwise manner, reducing the contact pressure with the shaft and allowing the contact force to decay smoothly. Then, the fine grinding zone is treated, and the shaft speed and contact pressure of the micro motor 6 are reduced again. Under the constant tension maintained by the automatic tensioning component 4, the process is completed. The grinding belt applies gentle, uniform pressure to refine the surface of the rotating shaft, resulting in a smooth and consistent final surface. The micro-motor 6 rotates the shaft at a high speed. By adjusting the initial tension of the spring and controlling the tightening wheel, the grinding belt applies greater contact pressure. The tighter grinding belt compacts the grinding area, ensuring efficient removal of roughness and burrs from the rotating shaft surface. This ensures high-pressure contact between the flexible grinding belt 21 and the rotating shaft surface, achieving rapid roughing and initially forming a relatively flat rotating shaft surface contour. As the shaft enters the transition zone, the speed gradually decreases. The speed of the rotating shaft is reduced in a stepwise manner to decrease the removal rate, reduce heat and stress concentration, and slowly reduce the tension of the flexible grinding belt 21, thereby reducing the contact pressure with the rotating shaft. The adjustment method mainly relies on the smooth movement of the hinge block 42 by the automatic tensioning component 4. The tension generated by the elastic element 44 naturally eases as the grinding belt wears or elongates, so that the contact force is smoothly attenuated. Guided by the trapezoidal distribution of the limiting block 22, the wrap angle of the flexible grinding belt 21 around the path gradually decreases, effectively coordinating the synchronous reduction of tension and speed, ensuring the synchronous gradual change of grinding pressure and speed, avoiding abrupt changes, and further reducing the rotation speed of the micro motor 6 shaft to enter the low-speed fine grinding stage. The speed is low enough to achieve fine and uniform surface finishing and prevent excessive surface cutting. The automatic tensioning component 4 continues to maintain a constant working tension of the flexible grinding belt 21, with the tension between medium and low in the overall range, maintaining a constant and stable working pressure to ensure that the flexible grinding belt 21 is in uniform contact with the rotating shaft surface, without loosening or slipping, finely removing residual minor unevenness on the surface, improving the surface finish and dimensional accuracy of the rotating shaft, and achieving the final process requirements.

[0045] S5: After the shaft of the micro motor 6 has finished grinding all three areas, stop running, release the workpiece positioning part 5, and take out the micro motor 6 that has finished grinding.

[0046] Furthermore, in step S1, the length of the area to be polished on the shaft of the micro motor 6 is equal to the width of the flexible polishing belt 21. When the flexible polishing belt 21 becomes loose due to wear or elongation, the helical spring drives the hinge block 42 and the second gear 43 to swing, automatically tightening the loose polishing belt and pulling it into the meshing gap of the gear to maintain constant working tension.

[0047] Working principle and usage process of this invention:

[0048] This invention maintains a constant tension on the flexible grinding belt 21 in real time through an automatic tensioning component 4. The component includes a first gear 41 fixed to a support 1, a hinge block 42 oscillatingly connected to the support 1, a second gear 43 disposed on the hinge block 42, and an elastic element 44 that biases the hinge block 42 toward the first gear 41. The first gear 41 and the second gear 43 mesh with each other, forming a gap at the meshing point for clamping the other end of the flexible grinding belt 21. When the flexible grinding belt 21 becomes loose due to wear or elongation, the elastic element 44 drives the hinge block 42 to swing, causing the second gear 43 to move toward the first gear 41, automatically tightening the loose grinding belt and pulling it into the meshing gap of the gears. This compensates for changes in the length of the grinding belt in real time, maintains a constant working tension, ensures stable contact pressure between the grinding belt and the rotating shaft during the grinding process, and avoids uneven grinding efficiency, quality fluctuations, and slippage problems caused by pressure decay.

[0049] The micro motor 6 to be polished is fixed to the workpiece positioning part 5, so that the rotating shaft of the micro motor 6 is accurately positioned below the flexible polishing belt 21. According to the characteristics of the area to be polished on the rotating shaft, the polishing path is divided into a rough polishing area, a fine polishing area, and a transition area. The initial working tension of the flexible polishing belt 21 is set by adjusting the initial tension of the helical spring, so that the rotating shaft rotates at a preset speed. At the same time, the tightening wheel 3 releases an appropriate length of polishing belt. First, the rough polishing area is treated by applying a large contact pressure and high-speed rotation to quickly remove the roughness and burrs on the surface of the rotating shaft. Then, the transition area is treated by gradually reducing the rotating shaft speed and contact pressure to make the contact force decay smoothly. Finally, the fine polishing area is treated by using gentle and uniform pressure to refine the surface of the rotating shaft under the constant tension maintained by the automatic tensioning component 4, so as to obtain a smooth and consistent final surface. After polishing is completed, the operation is stopped and the workpiece is removed.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A micro motor shaft polishing device, characterized in that, The device comprises a support part, a flexible polishing part, a tightening wheel part, an automatic tensioning assembly and a workpiece positioning part. The tightening wheel part is arranged on the support part. One end of the flexible polishing part is retractably fixed on the tightening wheel part. The automatic tensioning assembly is arranged on the support part and acts on the other end of the flexible polishing part. The workpiece positioning part is used for fixing a micro motor and making the rotating shaft of the micro motor below the flexible polishing part. The automatic tensioning assembly comprises a first gear fixed on the support part, a hinged block swingably connected to the support part, a second gear arranged on the hinged block and an elastic member for biasing the hinged block towards the first gear. The first gear and the second gear are in mesh with each other and form a gap for clamping the other end of the flexible polishing part at the meshing position. The elastic member compensates the length change of the flexible polishing part caused by wear or elongation by driving the hinged block to swing, thereby maintaining the constant working tension of the polishing belt.

2. The micro motor rotating shaft polishing device according to claim 1, wherein The flexible polishing part comprises a flexible polishing belt and a plurality of limiting blocks for guiding the flexible polishing belt. The plurality of limiting blocks are arranged on the support part. The flexible polishing belt is wound around the plurality of limiting blocks in sequence.

3. The micro motor rotating shaft polishing device according to claim 2, characterized in that, The number of the plurality of limiting blocks is 7. Four limiting blocks are arranged on the support part above the micro motor and are in trapezoidal distribution. Three limiting blocks are arranged on the support part near the tightening wheel part and are in triangular distribution.

4. The micro motor rotating shaft polishing device according to claim 2, characterized in that, The ratio of the width of the flexible polishing belt to the tooth width of the first gear or the second gear is 0.7-0.

9.

5. The micro motor shaft polishing device of claim 4, wherein The diameters and the number of teeth of the first gear and the second gear are the same. The clamping gap formed by the first gear and the second gear at the meshing position is 1.1-1.3 times the thickness of the flexible polishing belt.

6. The micro motor rotating shaft polishing device according to claim 1, wherein The elastic member is a spiral spring. One end of the spiral spring is arranged on the support part through a rotating block. The other end of the spiral spring is provided with an arc-shaped block. The inner wall of the arc-shaped block is engaged with one end of the hinged block.

7. The micro motor shaft polishing device of claim 6, wherein, The rotating block is rotationally connected to the support part. The inner wall of the arc-shaped block is provided with a silica gel block. A plurality of protrusions are arranged on the contact surface of the silica gel block. The heights of the plurality of protrusions gradually decrease from the inside of the opening of the arc-shaped block to the outside of the opening.

8. A micro motor shaft polishing method based on the micro motor shaft polishing device of any one of claims 1-7, characterized in that, The device comprises the following steps: S1: fixing the micro motor to be polished on the workpiece positioning part so that the rotating shaft of the micro motor is accurately positioned below the flexible polishing belt; S2: dividing the polishing path into a rough polishing area, a fine polishing area and a transition area according to the characteristics of the area to be polished of the rotating shaft of the micro motor; S3: setting the initial working tension of the flexible polishing belt by adjusting the initial stretching amount of the spiral spring, making the rotating shaft of the micro motor rotate at a preset rotating speed while the tightening wheel part releases a proper length of the polishing belt; S4: first, rough grinding zone processing is performed, the flexible polishing belt is caused to exert greater contact pressure by adjusting the initial tension of the coil spring and the control of the tightening wheel, the shaft is then driven to rotate at high speed to quickly remove the roughness and burrs on the surface of the shaft, transition zone processing is then performed, the rotation speed of the shaft is gradually reduced, the contact pressure with the shaft is reduced, the contact force is smoothly attenuated, fine grinding zone processing is then performed, the rotation speed of the shaft of the micro motor and the contact pressure are again reduced, under the guarantee of the constant tension maintained by the automatic tensioning assembly, the polishing belt gently and uniformly processes the surface of the shaft, thereby obtaining a smooth and consistent final surface; S5: when the shaft of the micro motor completes polishing in all three zones, the micro motor is stopped, the workpiece positioning part is loosened, and the micro motor that has completed polishing is taken out.

9. A method for grinding a micro motor shaft according to claim 8, characterized in that, The length of the shaft of the micro motor to be polished in step S1 is equal to the width of the flexible polishing belt.

10. The method of claim 8, wherein the step of polishing the shaft comprises the steps of: applying a first abrasive to the shaft; and applying a second abrasive to the shaft. 10 When the flexible polishing belt is loosened due to wear or elongation, the coil spring automatically tightens the loosened polishing belt into the meshing gap of the gear by driving the articulated block and the second gear to swing, so as to maintain the constant working tension.

Images