Stator fixing structure and method of brushless wiper motor

Abstract

The invention discloses a stator fixing structure of a brushless wiper motor, a stator component comprises an insulating sleeve and a stator punching sheet, the upper end part of the insulating sleeve is provided with wire passing grooves with different heights, and the stator punching sheet is provided with nine semicircular positioning grooves; the insulating sleeve covers the whole stator punching sheet winding groove by adopting integrated injection molding; the wiring sleeve component is assembled on the stator component, the stator component is arranged in the motor shell after the motor shell is heated, the motor shell is provided with a step structure, and the lower end of the step structure is in interference fit with the stator component; after the stator part is pressed into the motor shell in a hot jacket mode, the whole part is arranged into the speed reducer shell together, the unmatched length of the stator punching sheet and the motor shell is matched with the step A after the speed reducer shell is machined, and a step B for supporting the wiring sleeve part is designed on the speed reducer shell. The problems that a brushless front windscreen wiper motor is large in size and high in production and material cost, short-circuit risks exist between an enameled wire and a punching sheet, and a stator is not coaxial after being fixed are solved.

Description

Technical Field

[0001] This invention belongs to the field of motor technology and relates to a brushless motor, primarily used in automotive windshield wiper systems (but also applicable to other fields), providing power for wiping automotive windshields or other devices. More specifically, it relates to a stator fixing structure and method for a brushless wiper motor. Background Technology

[0002] Currently, all wiper motors on the market, whether mechanical or electronic, are brushed motors. The brushes and commutator are indispensable functional components of brushed motors, but they generate frictional noise during operation, resulting in relatively high overall motor noise. When the brushes and commutator commutate, commutation discharge generates sparks, causing brush erosion and rapid wear, thus limiting the motor's lifespan. The generation of commutation sparks also affects the motor's EMC performance. With the rapid development of the automotive industry, car owners and manufacturers have placed higher demands on vehicle comfort. The wiper system, as a standard functional component, cannot be eliminated. However, the wiper system is very close to the driver and central control components, and the motor noise directly affects the driver's auditory comfort. EMC performance also directly impacts the comfort of the cabin's instruments and equipment. To improve cabin noise comfort while reducing or avoiding the EMC impact of the wiper motor on cabin equipment, we have begun to introduce the concept of brushless wiper systems, upgrading brushed wiper motors to brushless wiper motors and making structural improvements.

[0003] The rotor of the existing wiper motor is fixed by the reducer housing using axial limiting mechanical fixation. The stator provides the magnetic field by bonding permanent magnets to the inner surface of the motor housing. Finally, the motor housing and the reducer housing are assembled together, so that the rotor is at the center of the magnetic field. After the power supply provides power to the motor, the rotor wires are charged conductors in the magnetic field and begin to rotate under the action of Ampere force.

[0004] A brushless motor consists of a stator, rotor, reducer housing, worm gear, and gland assembly. Its structure is an internal rotor, with magnets mounted on the rotor structure to provide a permanent magnet magnetic field. The stator is a combination of laminations and windings. One method for fixing the stator is to use long screws to tighten it to the reducer housing through pre-drilled holes in the laminations. This method is bulky, and the pre-drilled holes in the laminations complicate the structure, increasing the maximum outer diameter. Using bolts through these holes to fix the stator can lead to coaxiality issues between the stator, rotor, and reducer housing. Another method is to directly press-fit the stator assembly into the reducer housing. This method uses an aluminum reducer housing, resulting in a larger size and higher cost. Furthermore, traditional stator components use segmented insulating sleeves to insulate the enameled wire from the laminations. However, this method has the drawback that the intermediate insulating sleeves do not completely cover the lamination components, leading to a short circuit risk between the enameled wire and the laminations. Summary of the Invention

[0005] The purpose of this invention is to provide a stator fixing structure for a brushless wiper motor, which solves the problems of large size, high production and material costs, short circuit risk between enameled wire and lamination, and misalignment of the stator after fixing.

[0006] The technical solution of this invention is: A stator fixing structure for a brushless wiper motor includes a stator component 1, a wiring sleeve component 105, a reducer housing 3, a motor housing 2, and an insulating sleeve 101. The stator component 1 includes an insulating sleeve 101 and stator laminations 102. The insulating sleeve 101 has wire-passing grooves 103 of varying heights at its ends according to the winding sequence. The stator laminations 102 have nine semi-circular positioning grooves 104. The insulating sleeve 101 is integrally injection molded to cover the entire winding groove of the stator laminations. The terminal sleeve component 105 is assembled on the stator component 1. After heating the motor housing 2, the stator component 1 is installed into the motor housing 2. The motor housing 2 is provided with a stepped structure 201, and the lower end of the stepped structure 201 is interference-fitted with the stator component 1. After the stator component 1 is heat-pressed into the motor housing 2, the entire component is installed into the reducer housing 3. Part of the length of the stator component 1 does not contact or fit with the motor housing 2. The length of the stator lamination 102 that does not fit with the motor housing 2 fits with the step of the reducer housing 3 after machining. The upper part of the three steps A301 of the reducer housing 3 is machined. After the stator component 1 is installed into the reducer housing 3, the reducer housing 3 is designed with a step B302 to support the terminal sleeve component 105.

[0007] Furthermore, the semi-circular positioning groove 104 is located at the middle position of the alignment teeth on the outer circle of the lamination. This position is a sparse magnetic field region that does not affect the performance of the motor. The semi-circular positioning groove 104 is used for assembly positioning.

[0008] Furthermore, the major diameter of the stepped structure 201 is fitted with the stop of the reducer housing 3.

[0009] This invention has the following characteristics: 1. An innovative design was implemented for the front wiper motor housing structure, resulting in a simplified housing design where the motor stator components are partially embedded within the housing to ensure coaxiality between the stator and rotor. 2. The housing design features three bosses, which are machined into contact with the stator in one step, providing support for the coaxiality requirements after the stator is press-fitted.

[0010] 3. To meet assembly requirements, the reducer housing has a stop structure to ensure coaxiality during assembly. When assembling the stator laminations, part of the length extends into the reducer housing to ensure coaxiality between the stator and rotor. The motor housing is designed as a stepped structure.

[0011] 4. The stator components and insulating sleeve adopt an integrated injection molding structure, realizing a complete insulation design between the enameled wire and the lamination components, effectively solving the short circuit problem between the enameled wire and the lamination.

[0012] 5. Secondly, the enameled wire adopts the bottom passing method on the stator component, and the passing groove of the enameled wire on the insulation sleeve adopts an unequal height design, which effectively prevents the enameled wire from stacking during passing and causing inter-turn short circuit.

[0013] 6. The stator assembly and motor housing are assembled using a thermoforming interference fit. The steel motor housing is heated, increasing its inner diameter. The stator assembly is then inserted into the motor housing. After the motor housing cools, it is tightly secured to the stator assembly via an interference fit. This reduces the energy costs associated with the baking and solidification processes required for adhesive assembly.

[0014] 7. To ensure the consistency of the mating position between the stator outer surface and the housing, the stator laminations are riveted by rotation, with each lamination rotated 120 degrees (but not limited to 120-degree rotation), and every three laminations constitute one rotational riveting cycle. There are at least 13 rotational riveting cycles along the entire length of the stator, ensuring the coaxiality consistency between the stator outer diameter and inner diameter at various positions. This allows the stator to meet design tolerance requirements after being thermally fitted into the motor housing. Attached Figure Description

[0015] Figure 1 This is an isometric view of the stator component of the present invention; Figure 2 This is an isometric view of the stator after it has been heat-shrinken into the motor housing according to the present invention; Figure 3 This is a cross-sectional view of the stator component of the present invention after it has been installed into the housing. Figure 4 This is an isometric view of the housing of the present invention; Figure 5This is an isometric view of the housing of the present invention from another direction.

[0016] The markings in the diagram are: 1. Stator assembly, 2. Motor housing, 3. Reducer housing, 101. Insulating sleeve, 102. Stator lamination, 103. Wire groove, 104. Semi-circular positioning groove, 105. Terminal sleeve assembly, 201. Step structure, 301. Step A, 302. Step B. Detailed Implementation

[0017] The present invention will be further described below with reference to embodiments and accompanying drawings.

[0018] This embodiment describes in detail the fixing method and optimized design of a brushless front wiper motor stator. With appropriate changes to related parts such as the reducer housing, motor housing, and insulating sleeve, this structure can be used on other front and rear wiper motors.

[0019] like Figure 1 The image shows an isometric view of stator component 1. Stator component 1 has an insulating sleeve 101 and stator laminations 102. The insulating sleeve 101 has a wire passage groove 103, and the stator laminations 102 have nine semi-circular positioning grooves 104. The insulating sleeve 101 is integrally injection molded to cover the entire stator lamination winding groove, completely isolating the insulating sleeve from the enameled wire and preventing short circuits between the enameled wire and the stator laminations 102. The wire passage grooves 103 of the insulating sleeve 101 are opened at different heights at the ends according to the winding sequence, preventing the enameled wire from being squeezed and stacked at the same height when passing through, which would lead to short circuits and ensure the insulation performance of the motor. The semi-circular positioning grooves 104 are opened at the middle position of the alignment teeth on the outer circle of the lamination. This position is a sparse magnetic field area that does not affect the performance of the motor. The semi-circular positioning grooves 104 are used for assembly positioning and reduce the weight of the stator component, achieving motor lightweighting.

[0020] like Figure 2 The diagram shows the equiaxed side view of the stator component 1 after it has been heat-pressed into the motor housing 2. The terminal sleeve component 105 is assembled onto the stator component 1. The stator component 1 is installed into the motor housing 2 after the motor housing 2 is heated. The motor housing 2 is designed with a stepped structure 201. The lower end of the stepped structure 201 is interference-fitted with the stator component 1. The interference fit is achieved after heating, which simplifies assembly, eliminates the need for adhesives and heating, and reduces production costs. The major diameter of the stepped structure 201 is fitted with the stop of the reducer housing 3 to ensure the coaxiality of the motor housing 2 and the reducer housing 3.

[0021] like Figure 3 The image shown is an isometric view of the stator component 1 after it has been heat-pressed into the motor housing 2, and the entire component then being installed into the reducer housing 3. From... Figure 1As can be seen, stator component 1 and motor housing 2 are heat-fitted and then press-fitted after cooling. This assembly does not use any glue, making it simple and reliable. To ensure the coaxiality of the stator and rotor, stator component 1 is not directly fitted to motor housing 2, and a portion of the length of stator component 1 is not in contact with motor housing 2. The unfit length of the stator component 1 lamination is fitted with the machined step of reducer housing 3. To better illustrate the assembly relationship, isometric measurement of reducer housing 3 is performed separately. Figure 4 and Figure 5 As shown, the upper part of the three steps A301 of the whole circle is machined to ensure the fitting accuracy; after the stator component 1 is installed into the reducer housing 3, the reducer housing 3 is designed with step B302 to support the terminal sleeve component 105.

[0022] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of protection of the claims.

Claims

1. A stator fixing structure for a brushless wiper motor, characterized in that: The device includes a stator assembly (1), a terminal sleeve assembly (105), a reducer housing (3), a motor housing (2), and an insulating sleeve (101). The stator assembly (1) includes an insulating sleeve (101) and stator laminations (102). The insulating sleeve (101) has wire-passing grooves (103) of varying heights at its ends according to the order of winding. The stator laminations (102) have nine semi-circular positioning grooves (104). The insulating sleeve (101) is integrally injection molded to cover the entire winding groove of the stator laminations. The terminal sleeve component (105) is assembled on the stator component (1). After heating the motor housing (2), the stator component (1) is installed into the motor housing (2). The motor housing (2) is provided with a stepped structure (201). The lower end of the stepped structure (201) is interference-fitted with the stator component (1). After the stator component (1) is heat-pressed into the motor housing (2), the entire component is installed into the reducer housing (3). Part of the length of the stator component (1) does not contact the motor housing (2). The length of the stator lamination (102) that does not fit with the motor housing (2) matches the step A (301) of the reducer housing (3) after machining. The upper part of the three steps A (301) of the reducer housing (3) is machined. After the stator component (1) is installed into the reducer housing (3), the reducer housing (3) is designed with a step B (302) to support the terminal sleeve component (105).

2. The stator fixing structure of a brushless wiper motor as described in claim 1, characterized in that: The semicircular positioning groove (104) is located at the middle position of the alignment teeth on the outer circle of the lamination. This position is a sparse magnetic field region that does not affect the performance of the motor. The semicircular positioning groove (104) is used for assembly positioning.

3. The stator fixing structure of a brushless wiper motor as described in claim 1, characterized in that: The major diameter of the stepped structure (201) is fitted with the stop of the reducer housing (3).

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