End cap assembly for an electric machine and electric machine

Abstract

This utility model relates to an end cover assembly for a motor, and a motor including the end cover assembly. The end cover assembly includes an end cover body, a fixing plate, and a filter circuit board. The end cover body includes a peripheral wall and an end wall connected to an axial end of the peripheral wall, and the end wall is provided with a first through hole. The fixing plate includes a first section, a second section, and a connecting section. The filter circuit board is arranged in the first through hole and forms an annular gap with the inner peripheral surface of the first through hole. The first section abuts against the filter circuit board, the second section abuts against the end wall, and the connecting section is pressed into the annular gap with a pre-tightening force. The motor according to this utility model, by using a fixing plate, can effectively conduct and fix the filter circuit board and has a good grounding effect, providing effective protection for high electromagnetic compatibility during motor operation.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and more specifically to an end cover assembly for a motor and a motor including the end cover assembly. Background Technology

[0002] With the advancement of technology, the degree of electronic integration is increasing, and in fields such as automobiles and aerospace, the requirements for the electromagnetic interference resistance of electronic components in electronic systems are becoming increasingly stringent. As for brushed DC motors used in automobiles, the operating environment places extremely high demands on their electromagnetic compatibility.

[0003] A typical permanent magnet brushed DC motor usually consists of a stator with fixed main magnetic poles and brushes, and a rotor with armature windings and a commutator. The stator is integrated into the motor housing. Electrical energy from a DC power supply enters the armature windings through the brushes and commutator, generating armature current. The magnetic field generated by the armature current interacts with the main magnetic field to produce electromagnetic torque, causing the motor to rotate and drive the load. For brushed DC motors, the presence of brushes and the commutator causes commutation sparks during commutation, resulting in significant electromagnetic interference (EMI) during motor operation. Effective filtering circuits can significantly reduce this interference and improve electromagnetic compatibility.

[0004] Existing filtering circuits can be implemented using filters or filter circuit boards. Filters are typically located inside the motor housing and can be installed at the motor's power input to reduce interference propagating from the power lines. Alternatively, filters can be placed at the motor's output. However, both designs require additional shielding structures between the brushes and the filter, which is not only cumbersome but also fails to achieve high electromagnetic compatibility (EMC) characteristics. Especially for filter circuit board design, a suitable and reliable method and structure are typically needed to mount it outside the motor's metal casing, allowing the metal casing to provide effective shielding and filtering, thereby achieving high EMC characteristics. Utility Model Content

[0005] The purpose of this utility model is to solve at least one of the above-mentioned problems and / or other problems existing in the prior art.

[0006] To achieve the above objectives, this utility model provides an end cap assembly for a motor, the end cap assembly comprising: an end cap body, the end cap body including a peripheral wall and an end wall connected to an axial end of the peripheral wall to jointly define an end cap cavity with an opening at one end, the end wall having a first through hole; a fixing piece, the fixing piece including a first segment, a second segment, and a connecting segment connecting the first segment and the second segment, the first segment and the second segment defining a main body portion of the fixing piece, the connecting segment extending axially away from the main body portion; and a filter circuit board, the filter circuit board being disposed within the first through hole and forming an annular gap with the inner peripheral surface of the first through hole; wherein, the fixing piece is disposed on the end wall of the end cap body such that the first segment abuts against the filter circuit board, the second segment abuts against the end wall, and the connecting segment is pressed into the annular gap with a preload force to keep the filter circuit board relatively fixed to the end cap body within the first through hole.

[0007] In one embodiment, the first segment defines a second through hole through which the wiring harness of the filter circuit board passes.

[0008] In one embodiment, the connecting segment is composed of two curved segments opposite to each other, each curved segment bending away from the other curved segment; the connecting segment is elastically deformable such that when the connecting segment is inserted into the annular gap by an external force, the two curved segments are forced to deform and be tensioned in the annular gap by the preload.

[0009] In one embodiment, both the fixing piece and the end cap body are made of metal material, and the filter circuit board has a conductive layer on its entire circumferential side surface so as to form a surface contact grounding when the filter circuit board is in contact with the connecting section.

[0010] In one embodiment, the connecting segment, the first segment, and the second segment are integrally formed by stamping.

[0011] In one embodiment, the end wall includes a wall body and a boss extending axially away from the wall body from the peripheral wall, wherein the radial inner edge of the fixing piece is adapted to the outer shape of the boss.

[0012] In one embodiment, the second section of the fixing piece is provided with a first fixing hole, and the end wall is provided with a second fixing hole corresponding to the first fixing hole. The fastener passes through the first fixing hole and the second fixing hole to at least fix the fixing piece and the end cap body together.

[0013] According to another aspect of the present invention, an electric motor is provided, the electric motor including an electric motor body and an end cap assembly as described above.

[0014] In one embodiment, the end cap body of the end cap assembly is fitted onto the metal housing of the motor body through the opening, and the end cap body is made of metal material to define an electromagnetic shielding structure together with the metal housing of the motor body.

[0015] In one implementation, the motor is a permanent magnet brushed DC motor.

[0016] The end cap assembly of this utility model has a first through hole on the end cap body for receiving a filter circuit board, and an annular gap is formed between the inner circumferential surface of the first through hole and the outer circumferential edge of the filter circuit board. This allows the connecting section of the fixing piece to be pressed into the annular gap with a pre-tightening force, thereby keeping the filter circuit board relatively fixed to the end cap body. This effectively prevents the filter circuit board from moving or misaligning relative to the end cap body in any direction, providing a good fixing effect. In addition, since a conductive layer is provided on the outer circumferential edge of the filter circuit board, it can form good conductive contact with the metal end cap body, providing effective protection for high electromagnetic compatibility during motor operation. Attached Figure Description

[0017] The features and advantages of this utility model will become clear from the following detailed description provided with reference to the accompanying drawings. It should be understood that the following drawings are merely schematic and not necessarily drawn to scale, and therefore should not be considered as limitations on this utility model, wherein:

[0018] Figure 1 A perspective view of a motor according to an embodiment of the present invention is shown;

[0019] Figure 2 It shows Figure 1 An exploded view of the motor, especially its end cap assembly;

[0020] Figure 3 A front view of a retaining piece in an end cap assembly according to an embodiment of the present invention is shown;

[0021] Figure 4 It shows Figure 3 A cross-sectional view of the fixing piece along line AA in the middle;

[0022] Figure 5 It shows Figure 4 A magnified view of the details at point B of the fixing piece;

[0023] Figure 6 It shows Figure 5A schematic diagram showing the connecting section of the fixing piece inserted into the annular gap between the filter circuit board and the end cover body; and

[0024] Figure 7 A perspective view of a filter circuit board in an end cap assembly according to an embodiment of the present invention is shown. Detailed Implementation

[0025] Embodiments of the present invention are described below with reference to the accompanying drawings. In the following description, numerous specific details are set forth to enable those skilled in the art to more fully understand and implement the present invention. However, it will be apparent to those skilled in the art that implementations of the present invention may not include some of these specific details. Furthermore, it should be understood that the present invention is not limited to the specific embodiments described. Rather, the present invention can be conceived to be implemented with any combination of the features and elements described below, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments, and advantages are for illustrative purposes only and should not be construed as elements or limitations of the claims unless expressly set forth in the claims.

[0026] The terms "first" and "second" are used below to describe the elements of this application. These terms are used only to distinguish the individual elements and not to limit the nature, order, or number of these elements. The terms "comprising" and "having" are used to indicate an open-ended inclusion and mean that there may be additional elements / components besides those listed.

[0027] With the increasing popularity of electric vehicles, and considering the requirements for driving safety, the EMC (Electromagnetic Compatibility) levels of automotive electronic systems and components are becoming increasingly stringent. To prevent the motor from radiating excessive electromagnetic waves during operation, which could affect the normal operation of electronic systems in the vehicle, a metal shielding cover and a filter circuit board can be installed at the end of the motor to improve electromagnetic compatibility. Since the filter circuit board needs to be fixed to the outer surface of the metal shielding cover, and to ensure good conductive contact and grounding between the filter circuit board and the metal shielding cover, thus achieving good shielding and filtering, a suitable method and structure are needed to fix the filter circuit board. Therefore, this invention proposes an optimized installation structure and method for the filter circuit board, which allows for a stable and reliable fixation of the filter circuit board to the metal shielding cover (hereinafter referred to as the "end cover body" of the motor end cover assembly), isolating the filter circuit board from components such as brushes and commutators to achieve good shielding and filtering, thereby improving electromagnetic compatibility.

[0028] Figure 1 and Figure 2 A perspective view and an exploded view of a motor according to an embodiment of the present invention are shown respectively. For example... Figure 1-2As shown, the motor according to this embodiment may include a motor body 100 and an end cap assembly 200. The motor body 100 may include a metal housing 101, a rotor assembly (not specifically shown) with armature windings and a commutator mounted within the metal housing 101, and a plastic end cap 102 assembled to the metal housing 101. The metal housing 101 defines a housing cavity with a first opening, in which an oil-impregnated bearing may be press-fitted and a magnet (not specifically shown) may be fixedly mounted. Thus, as an example, the motor according to this invention is preferably a permanent magnet brushed DC motor, wherein two carbon brushes (not specifically shown) intended to contact the commutator may be arranged radially opposite to each other on the inner side of the plastic end cap 102 facing the housing cavity.

[0029] Reference Figure 1 and Figure 2 When the metal casing 101 is assembled with the plastic end cap 102, there is an interference fit between the metal casing 101 and the plastic end cap 102. Then, under the stamping action of the capping machine, the metal casing 101 is punched out with a bent surface that can be pressed into the capping groove of the plastic end cap 102. In this way, the plastic end cap 102 is firmly formed into a single piece with the metal casing 101 (see...). Figure 1 ).

[0030] Continue to refer to Figure 1 and Figure 2 As shown, the end cap assembly 200 according to this embodiment may further include an end cap body 1, a fixing piece 2, and a filter circuit board 3. The end cap body is made of metal material to define a closed metal structure (except for the gap at the mounting holes) together with the metal casing 101 of the motor body, forming an electromagnetic shielding structure. This effectively reflects and absorbs the radiated noise generated during motor operation, achieving excellent internal shielding of electromagnetic waves and suppressing their outward radiation.

[0031] The end cap body 1 may include a peripheral wall 11 and an end wall 12. The peripheral wall 11 is generally cylindrical and has a first axial end and a second axial end opposite each other in the axial direction. The end wall 12 is connected to the first axial end of the peripheral wall 11. The second axial end of the peripheral wall 11 has an opening 13, and the end cap body 1 defines an end cap cavity. For an assembled motor, the size of the opening 13 of the end cap body 1 is slightly larger than the outer diameter of the metal housing 101 and the plastic end cap 102, such that the end cap body 1 can be fitted onto the plastic end cap 102 through the opening 13 and extend in the axial direction to completely cover the plastic end cap 102 and at least partially cover the metal housing 101 (e.g., Figure 1 (As can be seen in the image), and a transition fit is formed between the end cap body 1, the metal shell 101, and the plastic end cap 102.

[0032] The end wall 12 is provided with a first through hole 14 for arranging the filter circuit board 3. The shape of the first through hole 14 is approximately the same as that of the filter circuit board 3, for example... Figure 2 The filter circuit board 3 shown is roughly rectangular in shape, and the first through hole 14 is also roughly rectangular. The shape of the first through hole 14 is slightly larger than the outer shape of the filter circuit board 3, thus creating an annular gap 4 between the filter circuit board 3 and the inner circumferential surface of the first through hole 14. Figure 6 As shown. Therefore, the filter circuit board 3 can be easily placed into the first through hole 14 during motor assembly. For example... Figure 1 As shown, the end wall 12 of the end cap body 1 includes a wall body and a boss 15. The wall body of the end wall 12 has a plate-like structure, and the boss 15 extends axially away from the peripheral wall 11 from the middle of the wall body of the end wall 12, so that the boss 15 can form a receiving cavity, thereby being able to completely cover the protruding petal-like structure on the plastic end cap 102 for fixing the bearing.

[0033] See next. Figures 3 to 5 This illustrates the specific structure of the fixing piece according to this embodiment. The fixing piece 2 can be made of beryllium copper or a metal material with equivalent conductivity and good ductility. For example... Figures 3 to 5 As shown, the radial inner edge of the fixing piece 2 is adapted to the external shape of the boss 15. For example, the fixing piece can be a generally semi-annular thin-walled structure, with its inner circle being close to the radius of the boss 15 and its outer circle being close to the outer diameter of the end wall 12, which facilitates the rapid pre-installation of the fixing piece 2.

[0034] See especially Figure 4 The fixing piece 2 may include a first segment 21, a second segment 22, and a connecting segment 23. The second segment 22 and the first segment 21 are preferably located in the same plane, such that the second segment 22 and the first segment 21 together define the main body portion of the plane of the fixing piece 2. The connecting segment 23 connects the first segment 21 and the second segment 22 and extends axially away from the main body portion, such that the connecting segment 23 can protrude beyond the main body portion. In this way, after the filter circuit board 3 is assembled into the first through hole 14 and abuts against the plastic end cap 102, the fixing piece 2 is arranged on the wall body of the end wall 12 so that the first section 21 can abut against the filter circuit board 3, the second section 22 abuts against the wall body of the end wall 12, and the connecting section 23 is pressed into the annular gap 4 with a certain pre-tightening force. In this way, the inner and outer sides of the connecting section 23 can press against the filter circuit board 3 and the end cap body 1 respectively in the annular gap 4, so that the filter circuit board 3 can be kept relatively fixed to the end cap body 1 in the first through hole 14.

[0035] Optionally, a wire harness 31 is provided on the filter circuit board 3, and the first segment 21 of the fixing piece 2 defines a second through hole 24 for the wire harness 31 on the filter circuit board to pass through. The second through hole 24 is, for example, rectangular in shape, but it can be set to any shape or size according to actual needs.

[0036] refer to Figure 5 As shown, the connecting segment 23 can be composed of two opposing curved segments 231, each of which bends away from the other. For example, the cross-section of the entire connecting segment is approximately olive-shaped, and each curved segment 231 can undergo slight elastic deformation. Therefore, when the connecting segment 23 is pressed into the annular gap 4 under external force, the two curved segments 231 can undergo elastic deformation, moving closer to each other and straightening within the annular gap 4 to store elastic potential energy. Thus, they can be tensioned within the annular gap 4 with a certain preload (see...). Figure 6 This effectively prevents the filter circuit board 3 from moving or misaligning in any direction during motor operation.

[0037] In this embodiment, both the fixing piece 2 and the end cap body 1 are made of metal, and the filter circuit board 3 has a conductive layer 31, such as a tin plating layer, on its entire circumferential surface. Figure 6 and Figure 7 As shown. In this way, when the two curved sections 231 of the connecting section 23 abut against the end cover body 1 and the filter circuit board 3 respectively, one curved section 231 forms a surface contact with the end cover body 1, and the other curved section 231 forms a surface contact with the conductive layer 31, thereby enabling the filter circuit board 3 to achieve surface contact grounding via the fixing piece 2, and better suppressing electromagnetic radiation.

[0038] Optionally, the connecting section 23 and the first section 21 and the second section 22 can be integrally formed by stamping.

[0039] See back Figure 2 and Figure 3 As shown, the second segment 22 of the fixing piece 2 is provided with a first fixing hole 25, and the end wall 12 of the end cap body 1 is provided with a second fixing hole 16 corresponding to the first fixing hole 25. The fastener 5 passes through the first fixing hole 25 and the second fixing hole 16, which can fix the fixing piece 2 and the end cap body 1 together. Further, the plastic end cap 102 can be provided with threaded holes 103 corresponding to the first fixing hole 25 and the second fixing hole 16. After the fastener 5 (such as a bolt, screw, etc.) passes through the first fixing hole 25 and the second fixing hole 16, it is threadedly connected to the plastic end cap 102 in the threaded hole 103, thereby fixing the fixing piece 2 (and the filter circuit board 3 fixed thereon) and the end cap body 1 to the plastic end cap 102.

[0040] This invention also provides an electric motor, which may include a motor body 100 and the aforementioned end cover assembly 200. The motor is preferably a permanent magnet brushed DC motor.

[0041] The end cap assembly of this invention features an elastic fixing piece on the end cap body for securing the filter circuit board. After assembling the metal end cap body, this elastic fixing piece can be easily pressed into the gap between the filter circuit board and the end cap body. The entire operation is simple and quick. Furthermore, the fixing piece ensures a reliable relative fixation between the filter circuit board and the end cap body, effectively preventing any movement or misalignment of the filter circuit board relative to the end cap body. In addition, because a conductive layer is provided on the outer periphery of the filter circuit board, it can form good conductive contact and grounding with the metal end cap body, effectively ensuring high electromagnetic compatibility during motor operation.

[0042] It should be noted that the embodiments described above should be considered exemplary only, and the present invention is not limited to these embodiments. By considering the contents of this specification, those skilled in the art can make various changes and modifications without departing from the scope or spirit of the present invention. The true scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An end cover assembly for an electric machine, characterized by The end cap assembly (200) includes: End cap body (1), the end cap body includes a peripheral wall (11) and an end wall (12) connected to an axial end of the peripheral wall to jointly define an end cap cavity with an opening (13) at one end, and a first through hole (14) is provided on the end wall. A fixing piece (2), the fixing piece comprising a first segment (21), a second segment (22), and a connecting segment (23) connecting the first segment and the second segment, the first segment (21) and the second segment (22) defining a main body portion of the fixing piece, the connecting segment extending axially away from the main body portion; and The filter circuit board (3) is arranged in the first through hole (14) and an annular gap (4) is formed between the filter circuit board and the inner circumferential surface of the first through hole; The fixing piece is arranged on the end wall of the end cover body such that a first section abuts against the filter circuit board, a second section abuts against the end wall, and the connecting section is pressed into the annular gap with a pre-tightening force to keep the filter circuit board relatively fixed to the end cover body in the first through hole.

2. The end cap assembly of claim 1, wherein, The first section defines a second through hole (24) through which the wire harness (31) of the filter circuit board passes.

3. The end cap assembly according to claim 2, characterized in that, The connecting section (23) is composed of two curved sections (231) facing each other, each curved section bending away from the other curved section; the connecting section (23) is elastically deformable such that when the connecting section is inserted into the annular gap by an external force, the two curved sections are forced to deform and are tensioned in the annular gap (4) by the preload.

4. The end cap assembly according to any one of claims 1 to 3, characterized in that, Both the fixing piece (2) and the end cap body (1) are made of metal material. The filter circuit board (3) has a conductive layer (31) on its entire circumferential side surface so as to form a surface contact grounding when the filter circuit board is in contact with the connecting section (23).

5. The end cap assembly according to any one of claims 1 to 3, characterized in that, The connecting section (23), the first section (21), and the second section (22) are integrally formed by stamping.

6. The end cap assembly according to any one of claims 1 to 3, characterized in that, The end wall (12) includes a wall body and a boss (15) extending axially away from the wall body away from the peripheral wall (11), the radial inner edge of the fixing piece (2) being adapted to the outer shape of the boss.

7. The end cap assembly according to any one of claims 1 to 3, characterized in that, The second section (22) of the fixing piece is provided with a first fixing hole (25), and the end wall is provided with a second fixing hole (16) corresponding to the first fixing hole. The fastener (5) passes through the first fixing hole and the second fixing hole to at least fix the fixing piece (2) and the end cap body (1) together.

8. An electric motor, characterized in that, It includes a motor body (100) and an end cap assembly (200) according to any one of claims 1 to 7.

9. The motor according to claim 8, characterized in that, The end cap body (1) in the end cap assembly is fitted onto the metal housing (101) of the motor body through the opening (13). The end cap body is made of metal material to define an electromagnetic shielding structure together with the metal housing of the motor body.

10. The motor according to claim 8 or 9, characterized in that, The motor is a permanent magnet brushed DC motor.

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