Motor capable of preventing electric corrosion of bearing

Abstract

The invention provides a motor capable of preventing electric corrosion of a bearing, and belongs to the technical field of motors. The problems of complex structure, high cost and motor damage caused by wear particles in the prior art are solved. The motor comprises a motor body, a motor rotating shaft and a bearing, the motor rotating shaft and the bearing are arranged in the motor body, an end cover is arranged on one side of a non-shaft-extension end of the motor rotating shaft, a first cavity is formed in the center of the end cover, an annular sealing piece is fixed in the first cavity, a spring is arranged in the center of the sealing piece, one end of the spring abuts against the bottom face of the first cavity, and a steel ball is arranged at the other end of the spring. The steel ball abuts against the motor rotating shaft under pushing of the spring. According to the scheme, the shaft current guiding structure is further simplified, the size is reduced, disassembly and assembly are convenient, the production and maintenance cost and difficulty are reduced, abrasion particles are sealed and collected while abrasion of conductive parts is reduced, and the service life of the whole motor is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of motors, and particularly refers to a motor for preventing bearing electrical erosion. Background Art

[0002] When a motor is operating, an axial voltage will inevitably be generated at both ends of the motor shaft. When the loop formed by the motor shaft, bearing, and bearing housing is conducting, a current will be generated in the loop. When the current passes through the bearing, it will cause local discharge on the bearing contact surface, resulting in microscopic melting and corrosion of the material surface, and ultimately causing the bearing to be damaged due to electrical erosion.

[0003] The Chinese invention patent with the publication number "CN109072974A" discloses an insulating bearing, which includes a pair of raceway rings arranged concentrically with each other. There are rolling elements between the raceway rings. At least one raceway ring is provided with an insulating layer. Annular grooves with an arc-shaped cross-section are formed on both end faces of the raceway ring provided with the insulating layer, and at least the surface from the non-raceway surface side circumference of the raceway ring to the annular groove is covered by the insulating layer.

[0004] The above solution blocks the current by spraying an insulating layer of a special material (such as a ceramic coating) on the bearing surface. However, the cost of the spraying material is high, and the spraying process is difficult, which will result in the production and maintenance costs and difficulties of the insulating bearing being much higher than those of ordinary bearings.

[0005] The Chinese utility model patent with the publication number "CN219018630U" discloses a device for guiding the shaft current of a motor rotor based on a spring contact structure, which includes a motor housing, a motor bearing, a motor shaft, a spring seat, and a conductive spring. The spring seat is composed of a spring seat cover and a spring support tube. A spring groove is provided on the inner wall of the left end of the spring support tube. The conductive spring is installed in the spring groove, and the spring seat equipped with the conductive spring is pushed into the motor shaft, and the shaft current is guided out through the contact between the conductive spring and the motor shaft.

[0006] In the above solution, the high-speed rotating motor shaft frictional contacts with the conductive spring, and the conductive spring is easily worn, seriously affecting the service life of the conductive spring. At the same time, the device lacks a corresponding sealing structure and cannot collect the particles generated by the wear of the conductive spring. When the particles enter the bearing, it will accelerate the bearing damage. When the particles enter the gap inside the motor, it may cause short circuits, high voltages, etc., resulting in motor damage. In addition, in this solution, the conductive spring is positioned by the spring seat, and an additional fixing structure is required to fix the spring seat in the motor. The overall structure uses more materials and occupies more space, the structure is complex, the cost is increased, and the installation and removal are more troublesome. At the same time, this structure cannot be adapted to some motor types with small volume and high compactness requirements. Summary of the Invention

[0007] Aiming at the deficiencies of the existing technology, the technical problem to be solved by the present invention is: how to further simplify the shaft current guiding structure, reduce the volume, facilitate disassembly and assembly, reduce the production and maintenance costs and difficulties, reduce the wear of the conductive components, and at the same time seal and collect the wear particles while guiding the shaft current of the motor to the ground, so as to improve the overall service life of the motor.

[0008] The object of the present invention can be achieved by the following technical solutions:

[0009] A motor for preventing bearing electrolytic corrosion, comprising a motor main body, a motor rotating shaft and a bearing arranged in the motor main body. A end cover is arranged on one side of the non-shaft extension end of the motor rotating shaft. A first concave cavity is arranged in the center of the end cover. The opening of the first concave cavity faces the motor rotating shaft, and the first concave cavity and the motor rotating shaft are concentrically arranged; A ring-shaped seal is fixed in the first concave cavity. A spring is arranged in the center of the seal. One end of the spring abuts against the bottom surface of the first concave cavity, and the other end is provided with a steel ball. The steel ball abuts against the motor rotating shaft under the push of the spring; The steel ball is fixed at the end of the spring and is in sliding contact with the motor rotating shaft. Alternatively, a limiting ring that faces the motor rotating shaft and has a reduced opening is arranged on the inner circumference of the seal. The diameter of the outer end of the reduced opening part of the limiting ring is smaller than the diameter of the steel ball and encloses the main body of the steel ball. The steel ball is in rolling contact with the spring and the motor rotating shaft; A retaining ring that protrudes towards the motor rotating shaft is arranged on the outer circumference of the seal. The retaining ring is in sealing contact with the non-shaft extension end of the motor rotating shaft to form a sealing cavity.

[0010] In this solution, by arranging a first concave cavity with an opening facing the motor rotating shaft in the center of the end cover, the seal and the spring are arranged in the first concave cavity, and the steel ball is pushed by the spring to keep good contact with the motor rotating shaft, so that the shaft current on the motor rotating shaft is led to the ground through the steel ball, the spring and the end cover, avoiding damage to the bearing caused by the shaft current; The above-mentioned components work together to provide a more simplified current guiding structure, which is smaller in volume, lighter in weight, more streamlined in structure, and more adaptable to small-volume and high-compactness motor types. Compared with the existing shaft current guiding structure, it has stronger universality; And the materials used for components such as the end cover, spring, steel ball, and sealing ring are conventional, and the production process is mature, thereby reducing the production difficulty and cost and achieving cost reduction and efficiency increase.

[0011] When the steel ball is fixed at the end of the spring, the steel ball slides against the motor rotating shaft. Compared with the prior art, the contact surface between the steel ball and the motor rotating shaft is smaller. Coupled with the higher strength of the steel ball itself, the wear generated is also smaller compared to the prior art. Or, when the steel ball is positioned at the end of the spring through a limiting ring with a reduced opening, the limiting ring cooperates with the spring to tightly hold the steel ball. The main body of the steel ball is contained by the limiting ring with a reduced opening, and only a part of it protrudes outside the opening of the limiting ring, effectively preventing the spherical steel ball from falling off. At this time, the steel ball can roll or slide against the spring and the motor rotating shaft respectively, further reducing wear. At this time, the spring, the steel ball, and the seal are positioned in the first concave cavity through the above two structures, eliminating the need for additional fixing structures inside the motor, further reducing the volume of the structure. At the same time, the entire current guiding structure is highly integrated on the end cover, a conventional component of the motor, and can be installed and disassembled together with the end cover during use, which is very convenient.

[0012] In addition, in this solution, the retaining ring of the seal is in sealing contact with the non-extended end of the motor rotating shaft to seal the contact area between the steel ball and the motor rotating shaft. A small amount of wear particles generated by the friction between the steel ball and the motor rotating shaft can fall into the sealing cavity, where the particles are collected and isolated to prevent them from falling into the bearing and the motor and causing damage, thereby improving the overall service life of the motor.

[0013] In this motor for preventing bearing electrolytic corrosion, the bottom end of the first concave cavity extends inwardly to form a second concave cavity. A first step is formed at the bottom surface of the first concave cavity. Both the first and second concave cavities are cylindrical, and the diameter of the first concave cavity is larger than that of the second concave cavity. The spring is arranged in the second concave cavity, and the seal is arranged at the second step.

[0014] The sizes of the steel ball, the spring, the second concave cavity, and the seal are adapted to each other. The spring and the steel ball are limited by the inner peripheral wall of the first concave cavity, so that there is no obvious swing or deflection during expansion and contraction and movement. The inner diameter of the seal continues the diameter of the first concave cavity. The steel ball can expand and contract back and forth and rotate freely in the channel formed by the first concave cavity and the seal under the action of the spring, and can also play a role in guiding and positioning the steel ball and the spring to avoid overall deflection. The motor rotating shaft, the first concave cavity, the spring, and the steel ball always move on the same axis during use, with good concentricity, improving the stability of the motor.

[0015] In this motor for preventing bearing electrolytic corrosion, a thimble hole is provided at the non-extended end of the motor rotating shaft. The thimble hole is recessed axially to form a thimble cavity. The diameter of the thimble cavity is smaller than the diameter of the steel ball. The thimble cavity is concentrically arranged with the first concave cavity. A conical inclined surface is provided at the opening of the thimble hole, and the inclined surface is tangent to the outer peripheral surface of the steel ball.

[0016] The thimble hole is a conventional component in the production of the motor rotating shaft. In this solution, the existing thimble hole is fully utilized. When in use, the front part of the spherical steel ball falls into the thimble cavity, and the spring provides elastic force to press tightly. The thimble hole can limit the steel ball, further improving the tightness of the contact between the motor rotating shaft and the steel ball and maintaining a good conduction effect. The inclined surface is treated similar to a chamfer, so that the inclined surface is tangent to the outer circumference of the steel ball, avoiding the contact between the steel ball and the sharp part of the thimble hole, reducing the damage of the steel ball and extending its service life.

[0017] In this motor for preventing bearing electrolysis, grease is provided in the first concave cavity, the sealing cavity, and the thimble cavity. The grease can reduce the wear of the steel ball, lower the temperature of the steel ball, improve the service life of the steel ball, and at the same time can also adhere to the wear particles and better collect the particles.

[0018] Compared with the prior art, the technical effects of the present invention are as follows:

[0019] First, all the shaft current guiding components of this motor are integrated on the end cover, which is a conventional component inside the motor. When in use, it can be installed and disassembled together with the end cover, which is very convenient.

[0020] Second, this motor does not need to set up additional fixing structures inside the motor. At the same time, each component is small in size and light in weight, and the structure is more streamlined, which can better adapt to the motor types with small volume and high compactness. Compared with the existing shaft current guiding structures, it has stronger universality. Moreover, the materials used for components such as the end cover, steel ball, and sealing ring are conventional, and the production process is mature, thus reducing the production difficulty and cost and achieving cost reduction and efficiency increase.

[0021] Third, this motor is in close contact with the motor rotating shaft through the retaining ring on the seal, realizing the sealing of the contact area between the steel ball and the motor rotating shaft. It can collect and isolate the particles generated when the steel ball contacts the motor rotating shaft, preventing the particles from falling into the bearing and the motor and causing damage. At the same time, the spherical steel ball and the motor rotating shaft have rolling friction, further reducing wear and improving the overall service life of the motor.

[0022] Fourth, the motor rotating shaft, the first concave cavity, the spring, and the steel ball of this motor always move on the same axis during use, with high concentricity and very good motor stability. Description of the Drawings

[0023] Figure 1 It is a cross-sectional view of the motor provided by the present invention.

[0024] Figure 2 It is an exploded view of the motor provided by the present invention.

[0025] Figure 3 It is a schematic diagram of the end cover structure provided by the present invention.

[0026] Figure 4It is a cross-sectional view of the end cover provided by the present invention.

[0027] Figure 5 It is an enlarged view of area A provided by the present invention.

[0028] Figure 6 It is a cross-sectional view of the end cover cooperating with the motor shaft provided by the present invention.

[0029] Figure 7 It is an enlarged view of area B provided by the present invention.

[0030] Figure 8 It is a schematic structural diagram of the seal provided by the present invention.

[0031] Figure 9 It is a cross-sectional view of the non-shaft extension end of the motor shaft provided by the present invention.

[0032] In the figure, 1 is the end cover, 11 is the first concave cavity, 12 is the first step, 13 is the second concave cavity, 2 is the spring, 3 is the steel ball, 4 is the seal, 41 is the retaining ring, 42 is the sealing cavity, 43 is the limiting ring, 7 is the motor body, 8 is the shaft, 81 is the thimble hole, 82 is the thimble cavity, 83 is the inclined surface, and 9 is the bearing. Specific Embodiments

[0033] The following are specific embodiments of the present invention and, in combination with the accompanying drawings, further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0034] As Figure 1 、 Figure 2 shown, a motor for preventing bearing electrolytic corrosion includes a motor body 7, a motor shaft 8 and a bearing 9 arranged in the motor body 7, and an end cover 1 is provided on one side of the non-shaft extension end of the motor shaft 8.

[0035] Preferably, as Figure 3 、 Figure 4 、 Figure 5 shown, a first concave cavity 11 is provided at the center of the end cover 1. One end of the first concave cavity 11 is open and the other end is closed. The open end of the first concave cavity 11 faces the motor shaft 8. The bottom of the first concave cavity 11 is recessed inward to form a first step 12 and a second concave cavity 13. The first and second concave cavities 11, 13 are both cylindrical and the diameter of the first concave cavity 11 is larger than that of the second concave cavity 13. The first and second concave cavities 11, 13 and the motor shaft 8 are concentrically arranged.

[0036] Preferably, as Figure 6 、 Figure 7 、 Figure 8As shown in the figure, a spring 2 is provided in the second concave cavity 13. One end of the spring 2 abuts against the bottom surface of the second concave cavity 13, and a steel ball 3 is provided at the other end. The steel ball 3, the end cover 1, and the spring 2 are all made of conductive materials. The steel ball 3 is pushed by the spring 2 to maintain good contact with the motor shaft 8, so that the shaft current on the motor shaft 8 is led out to the ground through the steel ball 3, the spring 2, and the end cover 1, avoiding damage to the bearing 9 caused by the shaft current. A ring-shaped seal 4 is provided in the second concave cavity 13. The seal 4 is fixed by means of a tight fit with the first concave cavity 11 or glue bonding. A raised retaining ring 41 is provided on the outer periphery of the seal 4. The retaining ring 41 is in close contact with the non-shaft extension end of the motor shaft 8 to form a sealed cavity 42, realizing the sealing of the contact area between the steel ball 3 and the motor shaft 8, and collecting and isolating the particles generated when the steel ball 3 contacts the motor shaft 8, preventing the particles from falling into the bearing and the motor and causing damage.

[0037] Furthermore, a raised limiting ring 43 is provided at the inner circumference of the seal 4. The limiting ring 43 is provided with a constricted opening. The diameter of the outer end of the constricted opening of the limiting ring 43 is smaller than the diameter of the steel ball 3 and encloses the main body of the steel ball 3. The limiting ring 43 cooperates with the spring 2 to tightly press the steel ball 3. Only a part of the steel ball 3 protrudes outside the opening of the limiting ring 43, effectively preventing the steel ball 3 from falling off. The steel ball 3 can rotate freely, converting the sliding friction into rolling friction when contacting the motor shaft 8, reducing the wear of the steel ball 3, and enabling the spring 2 and the steel ball 3 to be firmly fixed on the end cover 1 as a whole while the steel ball 3 can maintain good contact with the motor shaft 8.

[0038] Furthermore, the outer circumference of the steel ball 3 and the outer periphery of the spring 2 are respectively in contact with the inner circumferential surface of the first concave cavity 11. The diameter of the first concave cavity 11 is equal to the inner diameter of the seal 4. The steel ball 3, the spring 2, and the first concave cavity 11 with suitable dimensions can provide better stability. The spring 2 and the steel ball 3 are limited by the inner circumferential wall of the first concave cavity 11 and will not swing or deflect during expansion and contraction and movement. At the same time, the inner diameter of the seal 4 continues the diameter of the first concave cavity 11. The spherical steel ball 3 can stretch back and forth and rotate freely in the channel formed by the first concave cavity 11 and the seal 4 under the action of the spring 2, and can also play a role in guiding and positioning the steel ball 3 and the spring 2, avoiding overall deflection.

[0039] Preferably, as Figure 9 shown, a thimble hole 81 is provided at the non-shaft extension end of the motor shaft 8. The thimble hole 81 is recessed axially inward to form a thimble cavity 82. The diameter of the thimble cavity 82 is smaller than the diameter of the steel ball 3. The thimble cavity 82 is concentric with the first concave cavity 11. The thimble hole 81 is a conventional component in the production of the motor shaft 8. In this solution, the front part of the spherical steel ball 3 falls into the thimble cavity 82 during use, and is pressed tightly with the elastic force provided by the spring 2. The thimble hole 82 can limit the steel ball 3, further improving the tightness of the contact between the motor shaft 8 and the steel ball 3 and maintaining a good conduction effect.

[0040] Further, an inclined surface 83 is provided at the opening of the thimble hole 81. The inclined surface 83 is treated with a chamfer-like process. Grease is provided in the first cavity 11, the sealing cavity 4, and the thimble cavity 82. After the chamfer treatment, the contact position between the thimble hole 81 and the steel ball 3 is no longer so sharp, reducing the damage to the steel ball 3. The grease can reduce the wear of the steel ball 3, lower the temperature of the steel ball 3, increase the service life of the steel ball 3, and at the same time can also adhere to the wear particles to better collect the particles.

[0041] The above embodiments are only preferred embodiments of the present invention, and do not limit the protection scope of the present invention accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be covered within the protection scope defined by the claims of the present invention.

Claims

1. An electric motor for preventing electric corrosion of bearings, comprising a motor main body (7), a motor rotating shaft (8) and a bearing (9) arranged in the motor main body (7), characterized in that: On one side of the non-shaft extension end of the motor shaft (8), there is an end cover (1). A first concave cavity (11) is provided at the center of the end cover (1). The opening of the first concave cavity (11) faces the motor shaft (8), and the first concave cavity (11) is concentric with the motor shaft (8). A ring-shaped seal (4) is fixed in the first concave cavity (11). A spring (2) is provided at the center of the seal (4). One end of the spring (2) abuts against the bottom surface of the first concave cavity (11), and the other end is provided with a steel ball (3). The steel ball (3) abuts against the motor shaft (8) under the push of the spring (2). The steel ball (3) is fixed at the end of the spring (2) and is in sliding contact with the motor shaft (8). Alternatively, a limiting ring (43) that faces the motor shaft (8) and has a constricted opening is provided on the inner circumference of the seal (4). The diameter of the outer end of the constricted opening of the limiting ring (43) is smaller than the diameter of the steel ball (3) and encloses the main body of the steel ball (3). The steel ball (3) is in rolling contact with the spring (2) and the motor shaft (8). A retaining ring (41) that protrudes towards the motor shaft (8) is provided on the outer circumference of the seal (4). The retaining ring (41) is in sealing contact with the non-shaft extension end of the motor shaft (8) to form a sealing cavity (42).

2. The motor for preventing bearing electrolytic corrosion according to claim 1, characterized in that: The bottom end of the first concave cavity (11) extends inwards and concavely to form a second concave cavity (13). A first step (12) is formed at the bottom surface of the first concave cavity (11). Both the first and second concave cavities (11, 13) are cylindrical, and the diameter of the first concave cavity (11) is larger than that of the second concave cavity (13). The spring (2) is arranged in the second concave cavity (13), and the seal (4) is arranged at the first step (12).

3. The motor for preventing electric corrosion of bearings according to claim 1 or 2, characterized in that: A thimble hole (81) is provided at the non-shaft extension end of the motor shaft (8). The thimble hole (81) concavely forms a thimble cavity (82) along the axial direction. The diameter of the thimble cavity (82) is smaller than the diameter of the steel ball (3). The thimble cavity (82) is concentric with the first concave cavity (11). A conical inclined surface (83) is provided at the opening of the thimble hole (81), and the inclined surface (83) is tangent to the outer peripheral surface of the steel ball (3).

4. The motor for preventing bearing electro-erosion according to claim 3, wherein: Lubricating grease is provided in the first concave cavity (11), the sealing cavity (4), and the thimble cavity (82).

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