Encoder mounting structure of large motor

Abstract

The utility model relates to the technical field of motors, and discloses an encoder mounting structure of a large motor, which comprises an encoder, a casing, a front end cover arranged at one end of the casing, a rear end cover arranged at the other end of the casing, and a rotating shaft rotationally connected with the front end cover and the rear end cover, one end of the connecting shaft is in butt joint with the tail end of the rotating shaft, the other end of the connecting shaft extends out of the rear end cover, a stator portion of the encoder is in screw connection with the outer end face of the rear end cover, and a rotor portion of the encoder is sleeved on the tail end of the connecting shaft. According to the encoder mounting structure of the large motor, the connecting shaft is ingeniously arranged, so that a mounting step is provided for the rotor part of the encoder, and a complex and high-difficulty processing mode of turning a tiny step on the rotating shaft of the large motor for mounting the encoder is ingeniously avoided; the machining difficulties of uneven stress, shaft deflection change, out-of-control machining stability and the like which are easily caused by a traditional turning mode are solved, the machining difficulty is greatly reduced, and the machining efficiency and quality are improved.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and in particular to an encoder mounting structure for a large motor. Background Technology

[0002] In today's field of motor control, permanent magnet synchronous motors (PMSMs) are increasingly widely used due to their significant advantages. Combining encoders with PMSMs to construct closed-loop control systems has become the mainstream technology for controlling PMSMs.

[0003] In actual operation, the encoder plays a crucial role. It can provide real-time feedback on the motor's position and speed signals, enabling precise matching between the motor's permanent magnet magnetic field and the magnetic field generated by the stator, greatly improving the coordination between the motor's stator and rotor. Especially under low-speed, heavy-load conditions, motors equipped with encoders perform better in current control compared to motors without encoders.

[0004] In small motors, especially those with short iron cores, the compact size allows for direct machining of suitable structures on the shaft to mount the encoder rotor directly, such as creating steps on the shaft for the rotor to sit on. However, this approach is not feasible for large motors. When machining the shaft of a large motor, machining tiny steps at the tail end for encoder mounting, as is done with small motors, can easily lead to uneven stress distribution due to the large diameter and length of the shaft. Combined with the shaft's length, this can cause changes in shaft deflection, resulting in uncontrolled overall machining stability. This severely impacts the shaft's machining accuracy and quality, ultimately affecting encoder installation and the motor's normal operation.

[0005] It is evident that existing technologies still need improvement and enhancement. Utility Model Content

[0006] In view of the shortcomings of the prior art, the purpose of this utility model is to provide an encoder mounting structure for a large motor, which aims to replace the mounting method of directly machining and mounting the encoder step on the motor shaft.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] An encoder mounting structure for a large motor includes an encoder, a housing, a front cover at one end of the housing, a rear cover at the other end of the housing, and a rotating shaft rotatably connected to the front and rear covers. The rotating shaft has a coaxial connecting shaft at its tail end, one end of which is connected to the tail end of the rotating shaft, and the other end extending out of the rear cover. The stator of the encoder is screwed to the outer end face of the rear cover, and the rotor of the encoder is fitted onto the tail end of the connecting shaft.

[0009] As a further improvement to the above technical solution, the tail end of the rotating shaft is provided with a central hole, the bottom of the central hole is provided with a coaxial threaded hole, the connecting shaft is provided with an axially extending through hole, and the screw passes through the rotor part of the encoder, the through hole and the central hole in sequence and then connects with the threaded hole.

[0010] As a further improvement to the above technical solution, the connecting shaft includes a docking section, a positioning section and a fitting section connected in sequence. The end of the positioning section adjacent to the docking section is provided with a first alignment chamfer, and the entrance of the central hole is provided with a second docking chamfer corresponding to the first alignment chamfer. The diameter of the positioning section is larger than that of the fitting section, so that the positioning section forms a limiting end face at the end adjacent to the fitting section.

[0011] As a further improvement to the above technical solution, a pressure sleeve is fitted on the screw to press against the tail of the connecting shaft, and a flat washer and a spring locking washer are provided between the head of the screw and the pressure sleeve.

[0012] As a further improvement to the above technical solution, the rear cover is provided with a protective cover to cover the encoder.

[0013] As a further improvement to the above technical solution, the rear cover is provided with a wiring hole for the encoder wiring.

[0014] The beneficial effects of this utility model are as follows: Compared with the prior art, this utility model provides an encoder mounting structure for a large motor. By setting a connecting shaft, it provides an mounting step for the encoder rotor, which cleverly avoids the complex and difficult machining method of turning a small step on the large motor shaft for encoder mounting. It solves the machining difficulties such as uneven force, shaft deflection changes and loss of machining stability caused by traditional turning methods, greatly reducing the machining difficulty and improving machining efficiency and quality. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of an encoder mounted on the rear end cover of a large motor.

[0016] Figure 2 This is a cross-sectional view of the encoder mounted on a large motor.

[0017] Figure 3 for Figure 2 A magnified view of the L region.

[0018] Figure 4 Exploded view of the encoder mounting structure.

[0019] Figure 5 A schematic diagram showing the encoder mounted on the rear cover being covered by a protective cover.

[0020] Explanation of main component symbols: 1-Encoder, 11-Stator, 12-Rotor, 21-Housing, 22-Front end cover, 23-Rear end cover, 24-Way hole, 3-Shaft, 31-Center hole, 32-Threaded hole, 33-Second chamfer, 4-Connecting shaft, 41-Through hole, 42-Matching section, 43-Positioning section, 44-Packaging section, 45-First alignment chamfer, 46-Limiting end face, 51-Pressure sleeve, 52-Flat washer, 53-Spring locking washer, 6-Cover, 7-Screw. Detailed Implementation

[0021] This utility model provides an encoder 1 mounting structure for a large 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.

[0022] Please see Figures 1 to 4 This utility model provides an encoder mounting structure for a large motor, including an encoder 1, a housing 21, a front cover 22 disposed at one end of the housing 21, a rear cover 23 disposed at the other end of the housing 21, and a rotating shaft 3 rotatably connected to the front cover 22 and the rear cover 23 (e.g., through bearings). The rear end of the rotating shaft 3 is provided with a coaxial connecting shaft 4, one end of which is connected to the rear end of the rotating shaft 3, and the other end extends out of the rear cover 23. The stator part 11 of the encoder 1 is screwed to the outer end face of the rear cover 23, and the rotor part 12 of the encoder 1 is fitted onto the rear end of the connecting shaft 4.

[0023] In fact, the large motor also includes a rotor core mounted on the rotating shaft 3 and a stator core positioned between the housing 21 and the rotor core. The rotor core is equipped with magnets, and the stator core is equipped with stator windings. When the stator windings are energized, they generate a rotating magnetic field. Under the influence of the rotating magnetic field, the magnets on the rotor core drive the rotating shaft 3 to rotate, realizing the conversion of electrical energy into mechanical energy, and outputting power to the outside through the transmission end of the rotating shaft 3.

[0024] When the rotating shaft 3 rotates, the connecting shaft 4, which is connected to the tail end of the rotating shaft 3, also rotates. Since the rotor part 12 of the encoder 1 is fitted onto the tail end of the connecting shaft 4, the rotation of the connecting shaft 4 will drive the rotor part 12 of the encoder 1 to rotate synchronously. The stator part 11 of the encoder 1 is fixed to the outer end face of the rear cover 23 by screws. During the rotation of the rotor part 12, the encoder 1 can sense the position and speed changes of the rotor in real time, and thus generate corresponding position and speed signals. These signals are fed back to the motor control system to achieve precise control of the motor's operating status.

[0025] Compared with the prior art, the present invention provides an encoder 1 mounting structure for a large motor that ingeniously provides a mounting step for the rotor part 12 of the encoder 1 by setting a connecting shaft 4. This ingeniously avoids the complex and difficult machining method of turning a small step on the shaft of a large motor to install the encoder 1. It solves the machining difficulties such as uneven force, shaft deflection changes and loss of machining stability caused by traditional turning methods, greatly reducing the machining difficulty and improving machining efficiency and quality.

[0026] In fact, to facilitate the turning of the shaft 3, a center hole 31 is provided at the tail end of the shaft 3. The center of the lathe cooperates with the center hole 31 to position the shaft 3, ensuring that the shaft 3 maintains a stable center of rotation during machining. A coaxial threaded hole 32 is provided at the bottom of the center hole 31, and the connecting shaft 4 is provided with an axially extending through hole 41. The screw 7 passes through the rotor part 12 of the encoder 1, the through hole 41 and the center hole 31 in sequence and then mates with the threaded hole 32, forming a stable mechanical connection structure. This connection method tightly integrates the rotor part 12 of the encoder 1, the connecting shaft 4 and the shaft 3 into one unit. When the motor is running at high speed, it can effectively resist the centrifugal force, torque and other forces generated by rotation, avoid loosening or displacement between components, and ensure that the encoder 1 can continuously and stably follow the rotation of the shaft 3, providing accurate position and speed signals to the motor control system and ensuring stable motor operation.

[0027] Specifically, the connecting shaft 4 includes a docking section 42, a positioning section 43, and a fitting section 44 connected in sequence. The positioning section 43 has a first alignment chamfer 45 at its end adjacent to the docking section 42, and the entrance of the center hole 31 has a second docking chamfer 33 corresponding to the first alignment chamfer 45. When installing the connecting shaft 4 and the rotating shaft 3, these two alignment chamfers can automatically center the shaft, guiding the docking section 42 of the connecting shaft 4 to quickly and accurately insert into the center hole 31, greatly improving the accuracy and efficiency of docking. This reduces the time and difficulty of repeated adjustments due to inaccurate positioning during installation, further shortening the assembly cycle of the large motor.

[0028] Furthermore, the diameter of the positioning segment 43 is larger than that of the mounting segment 44, so that the positioning segment 43 forms a limiting end face 46 at the end adjacent to the mounting segment 44. The rotor portion 12 of the encoder 1 is mounted on the mounting segment 44, and the limiting end face 46 is flush with the rotor portion 12 of the encoder 1, providing a precise positioning reference for the assembly process. When installing the rotor portion 12 of the encoder 1, the operator only needs to align the rotor portion 12 with the limiting end face 46 to ensure that the installation position of the rotor portion 12 of the encoder 1 on the connecting shaft 4 is accurate, thus improving the accuracy and consistency of the assembly.

[0029] Furthermore, a pressure sleeve 51 is fitted onto the screw 7 to press down on the tail of the connecting shaft 4. The pressure sleeve 51, fitted onto the screw 7 and pressing down on the tail of the connecting shaft 4, increases the force application area of ​​the screw 7 on the connecting shaft 4. This makes the connecting shaft 4 more evenly stressed when subjected to complex forces such as torque and axial force generated by the motor operation, reducing the risk of damage or loosening due to excessive local stress. This greatly enhances the stability of the connection between the connecting shaft 4 and the rotating shaft 3, ensuring the coordinated and stable operation of all components during motor operation. A flat washer 52 and a spring locking washer 53 are provided between the head of the screw 7 and the pressure sleeve 51. The spring locking washer 53, due to its elastic properties, continuously applies a reverse force to the screw 7 after it is tightened. When the motor operation causes vibration, the spring locking washer 53 can promptly counteract the loosening tendency caused by the vibration, effectively preventing the screw 7 from loosening during long-term use, ensuring the reliability of the entire encoder 1 installation structure, and reducing the frequency of failures caused by loose connections. The flat washer 52 is located between the head of the screw 7 and the pressure sleeve 51. During the tightening process of the screw 7, it can evenly distribute the pressure of the head of the screw 7, avoid the head of the screw 7 from directly contacting the pressure sleeve 51 and causing damage such as scratches or deformation on the surface of the pressure sleeve 51, extend the service life of the pressure sleeve 51, and at the same time ensure the tightness and stability of the connection, thus providing a guarantee for the long-term stable operation of the entire installation structure.

[0030] Preferred options, please refer to Figure 5 The rear cover 23 is provided with a protective cover 6 to cover the encoder 1. The protective cover 6 can effectively prevent external contaminants such as dust, debris and water droplets from entering the encoder 1, avoiding damage or interference to the electronic components and precision mechanical parts of the encoder 1, greatly extending the service life of the encoder 1 and ensuring its stable operation.

[0031] A dedicated channel is provided for the wiring of encoder 1, see Figure 1 As shown, the rear end cover 23 has wiring holes 24 for the encoder 1 to pass through, allowing the encoder 1's wiring to pass through the rear end cover 23 in an orderly manner, avoiding messy tangling and greatly improving wiring efficiency. At the same time, this orderly wiring method also makes it easier for installers to quickly and accurately complete wiring connections during motor assembly, shortening the overall assembly time.

[0032] 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.

[0033] 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.

[0034] 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. An encoder mounting structure of a large electric machine, comprising an encoder, a casing, a front end cover provided at one end of the casing, a rear end cover provided at the other end of the casing, and a rotating shaft connected rotatably with the front end cover and the rear end cover, characterized in that, The tail end of the rotating shaft is provided with a coaxial adapter shaft, one end of the adapter shaft is connected with the tail end of the rotating shaft, and the other end extends out of the rear end cover, the stator part of the encoder is screw-connected with the outer end surface of the rear end cover, and the rotor part of the encoder is sleeved on the tail end of the adapter shaft.

2. The encoder mounting structure for a large electric machine according to claim 1, characterized by, The tail end of the rotating shaft is provided with a central hole, the bottom of the central hole is provided with a coaxial threaded hole, the adapter shaft is provided with an axially extending through hole, and a screw is sequentially threaded through the rotor part of the encoder, the through hole and the central hole and is connected with the threaded hole.

3. The encoder mounting structure for a large electric machine according to claim 2, characterized by, The adapter shaft comprises a connecting section, a positioning section and a sleeving section which are sequentially connected, the positioning section is provided with a first alignment chamfer adjacent to the end of the connecting section, the entrance of the central hole is provided with a second alignment chamfer corresponding to the first alignment chamfer, and the diameter of the positioning section is greater than that of the sleeving section, so that the positioning section forms a limiting end surface adjacent to the end of the sleeving section.

4. The encoder mounting structure for a large electric machine according to claim 2, characterized by, The screw is sleeved with a pressing sleeve which presses the tail end of the adapter shaft, and a flat washer and a spring locking washer are arranged between the head of the screw and the pressing sleeve.

5. The encoder mounting structure for a large electric machine according to claim 1, characterized by, The rear end cover is provided with a cover cover which covers the encoder.

6. The encoder mounting structure for a large electric machine according to claim 1, characterized by, The rear end cover is provided with a wire hole for the wire of the encoder.

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