Motor rotating shaft structure and permanent magnet servo motor

Abstract

The utility model relates to the technical field of motors, and discloses a motor rotating shaft structure and a permanent magnet servo motor, the motor rotating shaft structure comprises a rotating shaft main body and a bearing transition sleeve sleeved on the rotating shaft main body, the bearing transition sleeve comprises a first sleeve body section and a second sleeve body section which are integrally formed, and the diameter of the first sleeve body section is larger than that of the second sleeve body section. And the transition end surfaces of the first sleeve body section and the second sleeve body section and the peripheral surface of the second sleeve body section are plated with ceramic layers. According to the motor rotating shaft structure, the combination mode of the rotating shaft body and the bearing transition sleeve is innovatively used, ceramic plating machining is transferred to the bearing transition sleeve, ceramic plating machining does not need to be carried out on the motor rotating shaft, and the constraint that the clamping stroke of a machine tool is limited, and tool changing and tool setting are tedious in the whole shaft machining process is eliminated; the size of each part can be accurately controlled in the grinding machine machining process, so that the thickness of a ceramic plating layer is uniform, the surface flatness is high, the overall machining precision is greatly improved, the insulation performance reduction caused by machining errors is avoided, and a reliable guarantee is provided for effective inhibition of shaft current.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and in particular to a motor shaft structure and a permanent magnet servo motor. Background Technology

[0002] In the field of permanent magnet synchronous motors, especially those exceeding 90kW, suppressing shaft current is a critical issue. Shaft current damages bearings and lubrication systems through electrolytic corrosion, leading to mechanical failure, uncontrolled temperature rise, and equipment shutdown. Currently, the main suppression methods are: 1. Using ceramic bearings, which cost 5 to 10 times more than ordinary bearings, but the manufacturing cost is too high; 2. Plating an insulating layer (such as a ceramic layer) on the bearing location of the motor shaft is the mainstream method, but this method is more suitable for motor shafts with an outer diameter of 100mm and a length of 700mm or less. Beyond this range, the cost and processing difficulty are high. This is because after ceramic coating, precision grinding with a diamond grinder is required, which is troublesome due to tool changes and grinding machine tool alignment. Plating the entire shaft also presents problems such as inconvenient lifting and handling, limited machine tool clamping stroke, high processing costs, and large deformation and ceramic plating runout. The larger and longer the shaft, the higher the processing difficulty and risk.

[0003] It is evident that existing technologies still need improvement and enhancement. Utility Model Content

[0004] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a motor shaft structure and a permanent magnet servo motor, which aims to solve the shaft current problem and reduce the processing difficulty and manufacturing cost.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A motor shaft structure includes a shaft body and a bearing transition sleeve fitted on the shaft body. The bearing transition sleeve includes an integrally formed first sleeve segment and a second sleeve segment. The diameter of the first sleeve segment is larger than that of the second sleeve segment. The transition end face of the first sleeve segment and the second sleeve segment and the outer peripheral surface of the second sleeve segment are both coated with a ceramic layer. The ceramic layer on the second sleeve segment is used for bearing installation.

[0007] As a further improvement to the above technical solution, the bearing transition sleeve is provided with a keyway inside, and the rotating shaft body is provided with a key body that mates with the keyway.

[0008] As a further improvement to the above technical solution, a shaft shoulder is formed on the main body of the rotating shaft for axial positioning of the bearing transition sleeve, and an inner ring that cooperates with the shaft shoulder is formed inside the bearing transition sleeve.

[0009] As a further improvement to the above technical solution, the bottom corner of the shaft shoulder is rounded, and an avoidance groove is formed inside the bearing transition sleeve to avoid the rounded corner.

[0010] As a further improvement to the above technical solution, the rotating shaft body is fitted with a retaining ring for axial positioning of the bearing transition sleeve, and the rotating shaft body is provided with a slot for installing the retaining ring.

[0011] As a further improvement to the above technical solution, a limiting shoulder is provided at the end of the first body segment away from the second body segment.

[0012] As a further improvement to the above technical solution, the bearing transition sleeve and the shaft body are interference fit.

[0013] A permanent magnet servo motor is also provided, including a housing, a stator structure disposed within the housing, and a rotor structure, wherein the rotor structure includes the aforementioned motor shaft structure.

[0014] The beneficial effects of this utility model are as follows: Compared with the prior art, the motor shaft structure provided by this utility model innovatively uses a combination of the shaft body and the bearing transition sleeve to transfer the ceramic plating process to the bearing transition sleeve, eliminating the need for ceramic plating on the motor shaft. This frees the motor shaft from the constraints of limited tool clamping travel and cumbersome tool changing during whole shaft processing. It enables precise control of the dimensions of each part during grinding, resulting in uniform ceramic plating thickness and high surface flatness, greatly improving the overall processing accuracy, avoiding the decrease in insulation performance due to processing errors, and providing a reliable guarantee for the effective suppression of shaft current. Attached Figure Description

[0015] Figure 1 This is a cross-sectional view of the rotor structure of a permanent magnet servo motor.

[0016] Figure 2 for Figure 1 A magnified view of a portion of region A in the middle.

[0017] Figure 3 Three-dimensional bearing transition sleeve Figure 1 .

[0018] Figure 4 Three-dimensional bearing transition sleeve Figure 2 .

[0019] Figure 5 This is a three-dimensional view of the main body of the rotating shaft.

[0020] Figure 6 This is a 3D view of the rotor structure of a permanent magnet servo motor.

[0021] Figure 7 This is an exploded view of the rotor structure of a permanent magnet servo motor.

[0022] Explanation of main component symbols: 1-Shaft body, 11-Shaft shoulder, 12-Round corner, 13-Slot, 2-Bearing transition sleeve, 21-First body segment, 22-Second body segment, 23-Ceramic layer, 24-Keyway, 25-Inner ring, 26-Allowing groove, 27-Limiting shoulder, 3-Bearing, 4-Key body, 5-Retaining ring, 6-Rotor structure, 7-Bearing inner cover. Detailed Implementation

[0023] This utility model provides a motor shaft structure and a permanent magnet servo motor. To make the purpose, technical solution, and effects of this utility model clearer and more explicit, the following describes this utility model in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit the scope of protection of this utility model.

[0024] Please see Figures 1 to 7 This utility model provides a motor shaft structure, including a shaft body 1 and a bearing transition sleeve 2 sleeved on the shaft body 1. The bearing transition sleeve 2 includes an integrally formed first sleeve segment 21 and a second sleeve segment 22. The diameter of the first sleeve segment 21 is larger than that of the second sleeve segment 22. The transition end face of the first sleeve segment 21 and the second sleeve segment 22 and the outer peripheral surface of the second sleeve segment 22 are both coated with a ceramic layer 23. The ceramic layer 23 on the second sleeve segment 22 is used for the installation of the bearing 3.

[0025] In this motor shaft structure, the bearing transition sleeve 2 is manufactured independently of the shaft body 1. Its integrally formed first segment 21 and second segment 22 form a stepped structure. Because the bearing transition sleeve 2 is short and can be machined separately, the grinding machine stroke can be fully utilized, and the dimensions of each part can be precisely controlled, ensuring the uniformity and high precision of the ceramic layer 23 plating on the transition end faces of the first segment 21 and the second segment 22, as well as on the outer circumferential surface of the second segment 22. During operation of the permanent magnet servo motor, the shaft current is conducted along the shaft to the bearing transition sleeve 2. The high-precision plated ceramic layer 23 acts as an insulating barrier, stably and effectively blocking the conduction path of the shaft current. In particular, the ceramic layer 23 of the second segment 22, used to mount the bearing 3, achieves a tight and insulating fit with the bearing 3 through precise machining, completely isolating the bearing 3 from the shaft body 1, preventing the shaft current from forming a loop, and thus preventing electrolytic corrosion of the bearing 3 and the lubrication system, ensuring stable motor operation.

[0026] The innovative motor shaft structure provided by this utility model uses a combination of the shaft body 1 and the bearing transition sleeve 2 to transfer the ceramic plating process to the bearing transition sleeve 2, eliminating the need for ceramic plating on the motor shaft itself. This frees the motor shaft from the constraints of limited tool clamping travel and cumbersome tool changing during whole shaft machining. It enables precise control of the dimensions of each part during grinding, resulting in uniform thickness and high surface flatness of the ceramic plating layer 23, greatly improving the overall machining accuracy and avoiding the degradation of insulation performance due to machining errors, thus providing a reliable guarantee for the effective suppression of shaft current.

[0027] By reducing processing difficulty, shortening processing time, and avoiding the scrap rate caused by issues such as deformation and large runout of the ceramic plating area that are common in whole-shaft machining, the overall processing cost of the motor shaft structure is reduced by at least 10%. Furthermore, the elimination of expensive ceramic bearings further saves material costs, significantly improving the product's economic efficiency and market competitiveness while ensuring effective suppression of motor shaft current.

[0028] To effectively limit the circumferential rotation and axial movement of the bearing transition sleeve 2 relative to the shaft body 1, a keyway 24 is provided inside the bearing transition sleeve 2, and a key 4 that mates with the keyway 24 is provided on the shaft body 1. The keyway 24 of the bearing transition sleeve 2 and the key 4 on the shaft body 1 fit tightly together, forming a mechanical constraint. This prevents loosening or displacement between the bearing transition sleeve 2 and the shaft body 1 during high-speed operation of the permanent magnet servo motor due to shaft current suppression requirements, ensuring the overall stability and reliability of the motor shaft structure and reducing the risk of failure caused by unstable component connections.

[0029] A shoulder 11 is formed on the main body 1 of the rotating shaft for axial positioning of the bearing transition sleeve 2, and an inner ring 25 is formed inside the bearing transition sleeve 2 to cooperate with the shoulder 11. The tight cooperation between the shoulder 11 on the main body 1 and the inner ring 25 inside the bearing transition sleeve 2 provides a clear and stable axial positioning reference for the bearing transition sleeve 2, accurately defining its axial position on the main body 1. During operation of the permanent magnet servo motor, this effectively prevents the bearing transition sleeve 2 from affecting the shaft current suppression effect due to axial movement, ensuring the accuracy of the bearing 3's installation position and maintaining the stability and reliability of the motor shaft structure.

[0030] The bottom corner of the shaft shoulder 11 is rounded with a 12mm radius, and a relief groove 26 is formed within the bearing transition sleeve 2 to avoid the rounded corner 12. The rounded corner 12 design at the bottom corner of the shaft shoulder 11 avoids the localized strength reduction problem caused by stress concentration during motor operation, which is common in traditional right-angle structures. Stress concentration can easily cause cracks at the corner of the shaft shoulder 11, thus affecting the connection stability between the shaft body 1 and the bearing transition sleeve 2. The rounded corner 12 transition makes the stress distribution more uniform, effectively enhancing the structural strength and fatigue resistance of the shaft shoulder 11 and extending the service life of the motor shaft structure. Simultaneously, the relief groove 26 within the bearing transition sleeve 2 precisely matches the rounded corner 12 of the shaft shoulder 11, preventing additional compressive stress at the rounded corner 12 transition point and further ensuring the structural integrity of the shaft shoulder 11.

[0031] Furthermore, a retaining ring 5 for axially positioning the bearing transition sleeve 2 is fitted onto the shaft body 1, and a slot 13 for mounting the retaining ring 5 is provided on the shaft body 1. The slot 13 on the shaft body 1 fits tightly with the retaining ring 5, providing additional axial limiting protection for the bearing transition sleeve 2. During the operation of the permanent magnet servo motor, especially when facing complex and variable load conditions or frequent start-stop, the retaining ring 5 can effectively prevent the bearing transition sleeve 2 from moving axially, ensuring that the bearing transition sleeve 2 is always in a precise installation position, avoiding the impact of positional deviation on the shaft current suppression effect, and improving the stability and reliability of the motor shaft structure operation.

[0032] In practice, the first segment 21 of the bearing transition sleeve 2 is fitted with the bearing inner cover 7. During the operation of the permanent magnet servo motor, vibration and axial force may cause the bearing inner cover 7 to shift. Therefore, a limiting shoulder 27 is provided at the end of the first segment 21 away from the second segment 22. The limiting shoulder 27 forms a reliable blocking structure, effectively preventing the bearing inner cover 7 from sliding off axially, ensuring that the bearing inner cover 7 is always in the correct position, and maintaining the integrity and stability of the motor's internal structure. This avoids problems such as component collisions and loosening caused by the slippage of the bearing inner cover 7, thereby reducing the risk of motor failure and ensuring long-term stable operation of the motor.

[0033] The bearing transition sleeve 2 and the shaft body 1 are interference-fitted. A heat-fitting method ensures a tight fit, significantly enhancing the connection force and forming a stable initial connection foundation. Furthermore, the keyway 24 and key 4 provide circumferential constraint, effectively preventing the bearing transition sleeve 2 from rotating relative to the shaft body 1; the retaining ring 5 and slot 13 provide reliable axial positioning. These multiple connection methods work synergistically to strengthen the connection from both axial and circumferential directions, significantly improving the connection strength between the bearing transition sleeve 2 and the shaft body 1. Even under harsh conditions such as high speed and high torque of the permanent magnet servo motor, a stable connection is ensured, preventing loosening or displacement.

[0034] This utility model also provides a permanent magnet servo motor, including a housing, a stator structure and a rotor structure 6 disposed within the housing. The rotor structure 6 includes the aforementioned motor shaft structure, which greatly reduces processing time and difficulty, and also reduces the processing cost of the motor.

[0035] The permanent magnet servo motor adopts the above-mentioned motor shaft structure. Through the ceramic layer 23 insulation design of a specific part of the bearing transition sleeve 2, the shaft current conduction path is effectively blocked, avoiding the electro-erosion damage of the bearing 3 and the lubrication system caused by the shaft current. This solves the core problems of mechanical failure, temperature rise runaway and equipment shutdown caused by shaft current in traditional permanent magnet synchronous motors (especially models exceeding 90kW), and greatly improves the reliability and stability of motor operation.

[0036] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0037] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0038] It is understood that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of this utility model, and all such substitutions or changes should fall within the protection scope of this utility model.

Claims

1. A motor shaft structure, characterized in that, The device includes a rotating shaft body and a bearing transition sleeve fitted on the rotating shaft body. The bearing transition sleeve includes an integrally formed first sleeve segment and a second sleeve segment. The diameter of the first sleeve segment is larger than that of the second sleeve segment. The transition end face of the first sleeve segment and the second sleeve segment and the outer peripheral surface of the second sleeve segment are both coated with a ceramic layer. The ceramic layer on the second sleeve segment is used for bearing installation.

2. The motor shaft structure according to claim 1, characterized in that, The bearing transition sleeve has a keyway inside, and the rotating shaft body has a key that mates with the keyway.

3. The motor shaft structure according to claim 1, characterized in that, A shoulder is formed on the main body of the rotating shaft for axial positioning of the bearing transition sleeve, and an inner ring that mates with the shoulder is formed inside the bearing transition sleeve.

4. The motor shaft structure according to claim 3, characterized in that, The bottom corner of the shaft shoulder is rounded, and a clearance groove is formed inside the bearing transition sleeve to avoid the rounded corner.

5. The motor shaft structure according to claim 3, characterized in that, The rotating shaft body is fitted with a retaining ring for axial positioning of the bearing transition sleeve, and the rotating shaft body is provided with a slot for installing the retaining ring.

6. The motor shaft structure according to claim 1, characterized in that, A limiting shoulder is provided at the end of the first body segment that is away from the second body segment.

7. The motor shaft structure according to any one of claims 1-6, characterized in that, The bearing transition sleeve and the shaft body are interference fit.

8. A permanent magnet servo motor, characterized in that, It includes a housing, a stator structure disposed within the housing, and a rotor structure, wherein the rotor structure includes the motor shaft structure as described in any one of claims 1-7.

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