Brushless direct current motor
By using materials with the same or similar coefficient of thermal expansion as the bearing material, and embedded in the front cover through die-casting inlay technology, the problem of improper fit between the bearing seat and the bearing at extreme temperatures is solved, and the service life of the bearing is extended.
Patent Information
- Application Number
- CN202421836418.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-31
- Publication Date
- 2025-07-01
- Estimated Expiration
- 2034-07-31
AI Technical Summary
At extreme temperatures, the bearing seat and bearing materials have large differences in thermal expansion coefficients, resulting in large-size interference or clearance matching between the bearing seat and the bearing, which affects the service life of the bearing.
The bearing seat is made separately using materials with the same or similar coefficient of thermal expansion as the bearing material, and the bearing seat is embedded in the shaft hole of the front cover by die-casting to ensure that the bearing seat and the bearing always maintain proper coordination.
At extreme temperatures, the bearing seat and bearing are avoided inappropriate coordination, which reduces the wear and vibration of the bearing and extends the service life of the bearing.
Smart Images
Figure CN223052831U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of new energy, and particularly relates to a brushless DC motor. Background Art
[0002] In the prior art, in order to reduce the weight of the motor and achieve lightweight of the motor, generally, an aluminum alloy material with light weight and good structural strength is used to manufacture the motor housing. A bearing seat is integrally formed on the motor housing, and the bearing seat supports the rotor shaft through a bearing. Since the bearing seat is integrally formed with the motor housing and is made of aluminum alloy material, the thermal expansion coefficient of the aluminum alloy material is relatively large, while the thermal expansion coefficient of the material for manufacturing the bearing is relatively small. On the one hand, in the case of extremely low temperature, the shrinkage degree of the bearing seat is greater than that of the bearing, resulting in a large-size interference fit between the bearing seat and the bearing, causing the bearing seat to exert a large extrusion on the bearing, affecting the bearing clearance or causing too large bearing resistance friction, and greatly reducing the service life of the bearing. On the other hand, in the case of extremely high temperature, the expansion degree of the bearing seat is greater than that of the bearing, resulting in a large-size clearance fit between the bearing seat and the bearing, causing the bearing to loosen in the bearing seat hole, easily generating vibration and noise, and increasing the wear of the bearing and the bearing seat, reducing the service life of the bearing. Summary of the Invention
[0003] In view of the above problems, the utility model provides a brushless DC motor. First, a bearing seat is separately manufactured from a material with the same or similar thermal expansion coefficient as that of the bearing material, and then the bearing seat is injection-molded and cast into the front cover to improve the service life of the bearing.
[0004] The technical solution of the utility model is as follows: A brushless DC motor includes a motor housing, a front cover, a rear cover, and a stator and a rotor disposed in the motor housing. The shaft of the rotor is supported by a bearing on the front cover and extends outward. The motor housing and the front cover are both made of aluminum alloy material. A bearing seat is injection-molded and inlaid in the shaft hole of the front cover. The thermal expansion coefficient of the bearing seat material is less than that of the aluminum alloy material of the front cover, and is the same or similar to the thermal expansion coefficient of the bearing outer ring material. The bearing seat is provided with a flange for axial and circumferential positioning, and the flange is radially embedded in the inner wall of the shaft hole of the front cover.
[0005] Preferably, the flange is an annular flange located in the middle section of the bearing seat, and at least two symmetric tangent planes are provided on the circumference of the flange.
[0006] Preferably, the bearing seat is injection-molded and inlaid in the shaft hole of the front cover, and a stop is formed in the shaft hole to prevent the bearing seat from axially moving.
[0007] Preferably, one end of the bearing seat is provided with a limiting step extending inward.
[0008] Preferably, a plurality of sealing ring mounting grooves are provided in the bearing seat hole, and an O-ring is sleeved inside each sealing ring mounting groove.
[0009] Preferably, a snap ring groove for a hole is provided in the bearing seat hole, and a snap ring for a hole is provided in the snap ring groove for a hole.
[0010] Preferably, sealing ring mounting grooves are provided on the outer circles of the front cover, the motor housing, and the rear cover, and O-rings are arranged in each sealing ring mounting groove.
[0011] Preferably, a spacer sleeve is provided between the rotor and the stator. The spacer sleeve is installed on the side of the boss inside the front cover. A sealing ring mounting groove is provided on the boss inside the front cover, and an O-ring is arranged in the sealing ring mounting groove.
[0012] Preferably, an external connector is provided on the outer side of the rear cover, and an internal connector is provided on the inner side of the rear cover for connecting to a controller.
[0013] Preferably, a controller is arranged on the rear end face of the motor housing, and the controller is electrically connected to the stator through a plurality of conductive terminals.
[0014] The advantages of the present utility model are as follows: By separately manufacturing the bearing seat with a material having the same or similar coefficient of thermal expansion as that of the bearing material, it is ensured that the bearing seat and the bearing always maintain an interference fit under extreme temperatures, avoiding the problem that due to a large difference in the coefficients of thermal expansion of the bearing seat material and the bearing material under extreme temperatures, a large-size interference fit or a large-size clearance fit is formed between the bearing seat and the bearing, reducing the service life of the bearing. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 is a schematic structural diagram of the present utility model;
[0016] Figure 2 is Figure 1 an enlarged view of part A of
[0017] Figure 3 is a schematic structural diagram of the bearing seat of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0018] See Figures 1 to 3, A brushless DC motor, comprising a motor housing 5, a front cover 4, a rear cover 6, and a stator 1 and a rotor 2 disposed in the motor housing 5. The rotating shaft 3 of the rotor 2 is supported by a bearing 8 on the front cover 4 and extends outward. An isolation sleeve 10 is provided between the rotor and the stator, and the isolation sleeve 10 is installed on the side of the boss inside the front cover 4. The boss inside the front cover 4 is provided with a sealing ring installation groove, and an O-ring is arranged in the sealing ring installation groove. A controller 11 is arranged on the rear end face of the motor housing 5, and the controller 11 is electrically connected to the stator 1 through a plurality of conductive terminals 12. In this embodiment, the controller 11 can be electrically connected to the stator 1 through three conductive terminals 12. An external connector 61 is provided on the outer side of the rear cover 6 for connecting a power supply, inputting a control signal, receiving a feedback signal, etc., and an internal connector 62 is provided on the inner side of the rear cover 6 for connecting the controller 11. The motor housing 5 and the front cover 4 are both made of aluminum alloy material. A bearing seat 7 is die-cast and embedded in the shaft hole of the front cover 4. The thermal expansion coefficient of the material of the bearing seat 7 is less than that of the aluminum alloy material of the front cover 4, and is the same as or close to the thermal expansion coefficient of the outer ring material of the bearing 8. For example, the outer circle material of the bearing 8 is bearing steel, and the bearing seat 7 is also made of bearing steel, so that the materials of the bearing seat 7 and the outer circle of the bearing 8 are the same, ensuring that the thermal expansion coefficient of the material of the bearing seat 7 is less than that of the aluminum alloy material of the front cover 4, and is the same as the thermal expansion coefficient of the outer ring material of the bearing 8. Or the outer circle material of the bearing 8 is bearing steel, and the bearing seat 7 is made of No. 10 steel, ensuring that the thermal expansion coefficient of the material of the bearing seat 7 is less than that of the aluminum alloy material of the front cover 4, and is close to the thermal expansion coefficient of the outer ring material of the bearing 8. The bearing seat 7 is provided with a flange 71 for axial and circumferential positioning, and the flange 71 is radially embedded in the inner wall of the shaft hole of the front cover 4. The flange 71 is an annular flange located in the middle section of the bearing seat 7. At least two symmetric cutting planes 72 are provided on the circumference of the flange 71 for circumferentially positioning the bearing seat 7 to prevent the bearing seat 7 from rotating. The bearing seat 7 is die-cast and embedded in the shaft hole of the front cover 4, and a stop 41 is formed in the shaft hole to prevent the bearing seat 7 from axially moving. One end of the bearing seat 7 is provided with a limiting step 74 extending inward, and the bearing 8 is assembled through the other end of the bearing seat 7, so that the limiting step 74 limits the bearing 8. Two sealing ring installation grooves 73 and a snap ring groove for a hole are provided in the hole of the bearing seat 7, and O-rings are sleeved in both of the two sealing ring installation grooves 73. A snap ring 9 for a hole is arranged in the snap ring groove for a hole for limiting the bearing 8. Sealing ring installation grooves are provided on the outer circles of the front cover 4, the motor housing 5, and the rear cover 6, and O-rings are arranged in each of the sealing ring installation grooves.
[0019] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Those skilled in the art can make modifications to the present invention without departing from the spirit of the present invention, and such modifications fall within the protection scope of the present invention.
Claims
1. A brushless DC motor, comprising a motor housing (5), a front cover (4), a rear cover (6), and a stator (1) and a rotor (2) arranged in the motor housing (5), wherein a rotating shaft (3) of the rotor (2) is supported on the front cover (4) through a bearing (8) and extends outward, wherein the motor housing (5) and the front cover (4) are both made of aluminum alloy material, and characterized in that: A bearing seat (7) is embedded in the shaft hole of the front cover (4) by die-casting. The thermal expansion coefficient of the material of the bearing seat (7) is smaller than the thermal expansion coefficient of the aluminum alloy material of the front cover (4), and is the same as or similar to the thermal expansion coefficient of the material of the outer ring of the bearing (8). The bearing seat (7) is provided with a flange (71) for axial and circumferential limiting, and the flange (71) is radially embedded in the inner wall of the shaft hole of the front cover (4).
2. A brushless DC motor according to claim 1, characterized in that: The flange (71) is an annular flange located in the middle section of the bearing seat (7), and the circumference of the flange (71) is provided with at least two symmetrical tangent planes (72).
3. A brushless DC motor according to claim 1, characterized in that: The bearing seat (7) is die-cast and embedded in the shaft hole of the front cover (4), and the shaft hole is formed with a stopper (41) for preventing the bearing seat (7) from axial movement.
4. A brushless DC motor according to claim 1, characterized in that: One end of the bearing seat (7) is provided with a limiting step (74) extending inwards.
5. A brushless DC motor according to claim 1, characterized in that: A plurality of sealing ring installation grooves (73) are provided in the hole of the bearing seat (7), and each sealing ring installation groove (73) is sleeved with an O-type sealing ring.
6. A brushless DC motor according to claim 1, characterized in that: A hole clamping ring groove is provided in the hole of the bearing seat (7), and a hole clamping ring sleeve (9) is provided in the hole clamping ring groove.
7. A brushless DC motor according to claim 1, characterized in that: The outer circles of the front cover (4), the motor housing (5) and the rear cover (6) are all provided with sealing ring installation grooves, and each sealing ring installation groove is provided with an O-type sealing ring.
8. The brushless DC motor according to claim 1, characterized in that: An isolation sleeve (10) is provided between the rotor and the stator, and the isolation sleeve (10) is mounted on the boss side of the inner side of the front cover (4). The boss on the inner side of the front cover (4) is provided with a sealing ring installation groove, and an O-type sealing ring is arranged in the sealing ring installation groove.
9. The brushless DC motor according to claim 1, characterized in that: An external connector (61) is provided on the outside of the rear cover (6), and an internal connector (62) is provided on the inside of the rear cover (6) for connecting to a controller.
10. The brushless DC motor according to claim 1, characterized in that: A controller (11) is provided on the rear end surface of the motor housing (5), and the controller (11) is electrically connected to the stator (1) via a plurality of conductive terminals (12).