Motor assembly and electric power steering system
By press-fitting a conductive elastomer between the motor housing and the controller, combined with the stepped inner wall and annular slot design, the problem of insufficient thermal conductivity and electromagnetic shielding performance in the connection between the motor housing and the controller in the existing technology is solved. , achieving a motor assembly with simple structure, convenient assembly and high stability.
Patent Information
- Application Number
- CN202421038607.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-14
- Publication Date
- 2025-01-21
- Estimated Expiration
- 2034-05-14
AI Technical Summary
The connection between the existing motor housing and the controller has problems in thermal conductivity and electromagnetic shielding performance, including high cost, complex operation and difficult-to-control gaps, and poor reliability of the copper clamp affects electromagnetic shielding performance.
By pressing the conductive elastomer between the motor housing and the controller, its thermal and electrical conductivity properties are used, combined with the stepped design of the inner wall of the motor housing and the annular slot on the outer wall of the controller, to ensure that the conductive elastomer is firmly embedded. And grounded to improve thermal conductivity and electromagnetic shielding performance.
This achieves a motor assembly with simple structure, convenient assembly and high stability, which can effectively control the gap between the motor housing and the controller, and stably exert thermal conductivity and electromagnetic shielding performance.
Smart Images
Figure CN222372957U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of steering, in particular to a motor assembly and an electric power steering system. Background Art
[0002] In the electric power steering system, the motor used for power steering usually adopts a cylindrical structure design, and the motor controller is assembled in the motor housing. The connection between the motor housing and the controller needs to consider thermal conductivity and electromagnetic shielding performance (EMC: Electromagnetic Compatibility).
[0003] At present, the thermal conductivity and electromagnetic shielding performance of the connection between the motor housing and the controller are achieved in the following ways:
[0004] A circle of glue is formed on the inner wall of the motor housing, and then the controller is assembled into the motor housing to achieve heat conduction to the controller through glue. The problem with this approach is that the cost of glue equipment and materials is high, the operation is complicated, and the gap between the controller and the motor housing is difficult to control (if the gap is large, it is not good for thermal conductivity, and if the gap is small, it will affect rework and repair).
[0005] A grounding copper clip is installed on the outer wall of the controller to achieve electromagnetic shielding performance. The problem with this approach is that the assembly of the copper clip is cumbersome, the reliability of the copper clip is poor, and there is a large degree of freedom of deformation, which affects the electromagnetic shielding performance.
[0006] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the utility model, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Utility Model Content
[0007] In view of this, the utility model provides a motor assembly and an electric power steering system, which realize thermal conductivity and electromagnetic shielding performance by pressing a conductive elastomer between the motor housing and the controller. It has the advantages of simple structure, easy assembly and high stability, can effectively control the gap between the motor housing and the controller, and stably exert thermal conductivity and electromagnetic shielding performance.
[0008] One aspect of the utility model provides a motor assembly, including a cylindrical motor housing and a controller assembled in the motor housing, wherein: the inner wall of the motor housing includes a first step wall and a second step wall forming a step shape, and the inner diameter of the first step wall is larger than the inner diameter of the second step wall; the outer wall of the controller is provided with an annular groove, and a conductive elastomer is embedded in the annular groove. As the controller is assembled into the motor housing from the first step wall, the conductive elastomer is pressed between the first step wall and the annular groove, and the conductive elastomer is grounded.
[0009] In some embodiments, the controller is formed into a frustum with a gradually changing outer diameter, and the small end and the large end of the controller are successively assembled into the motor housing.
[0010] In some embodiments, the motor housing and the controller are clearance-fitted; and the maximum distance between the first step wall and the outer wall of the controller is smaller than the outer diameter of the conductive elastomer.
[0011] In some embodiments, the minimum spacing between the inner wall of the motor housing and the outer wall of the controller is 0.8 mm.
[0012] In some embodiments, the first step wall and the second step wall are connected via an inclined surface.
[0013] In some embodiments, the cross-section of the conductive elastomer is formed into a ring shape.
[0014] In some embodiments, the conductive elastomer is conductive rubber.
[0015] In some embodiments, the conductive elastomer has one or more of the following performance parameters: resistivity: 0.02 ohm-cm; elongation: 150%; thermal conductivity: 1 W / (m*K).
[0016] In some embodiments, the outer wall of the controller is provided with a plurality of circles of the annular grooves, and a circle of the conductive elastomer is embedded in each circle of the annular grooves.
[0017] Another aspect of the present invention provides an electric power steering system, wherein the electric power steering system is configured with a motor assembly as described in any of the above embodiments.
[0018] Compared with the prior art, the beneficial effects of the present invention include at least:
[0019] The motor assembly of the utility model adopts a conductive elastomer with both thermal and electrical properties, which is pressed between the motor housing and the controller, and the conductive elastomer is grounded, so as to achieve the thermal conductivity and electromagnetic shielding performance of the motor assembly. Specifically, an annular groove is provided on the outer wall of the controller, so that the conductive elastomer is firmly embedded in the annular groove; the conductive elastomer is pressed between the motor housing and the controller when the controller is assembled into the motor housing; the inner wall of the motor housing forms a step wall, which can effectively prevent the conductive elastomer from slipping, so that the conductive elastomer is always pressed between the motor housing and the controller, and the contact and connection are stable and reliable; the size and deformation capacity of the conductive elastomer can be set as needed, so as to accurately control the gap between the motor housing and the controller.
[0020] Therefore, the motor assembly of the utility model realizes thermal conductivity and electromagnetic shielding performance by pressing the conductive elastomer between the motor housing and the controller. It has the advantages of simple structure, easy assembly and high stability. It can effectively control the gap between the motor housing and the controller and stably exert the thermal conductivity and electromagnetic shielding performance.
[0021] It should be understood that the above general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present utility model, and together with the specification, are used to explain the principles of the present utility model. Obviously, the drawings described below are only some embodiments of the present utility model, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0023] Figure 1 A partial structural schematic diagram of a motor assembly in an embodiment of the utility model is shown;
[0024] Figure 2 A schematic diagram showing the heat conduction and electromagnetic shielding structure of the motor assembly in an embodiment of the utility model is shown. DETAILED DESCRIPTION
[0025] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein. Instead, these embodiments are provided so that the present invention will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their repeated description will be omitted.
[0026] The words "first", "second" and similar words used in the specific description do not indicate any order, quantity or importance, but are only used to distinguish different components. In the description of the present utility model, "plurality" means two or more, unless otherwise clearly and specifically defined. In addition, in the description of the present utility model, when it is said that a device is "connected" to another device, this includes not only the case of direct connection, but also the case of indirect connection through other elements.
[0027] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in different embodiments may be combined with each other.
[0028] Figure 1 The partial structure of the motor assembly in the embodiment of the utility model is shown in FIG. Figure 2The heat conduction and electromagnetic shielding structure of the motor assembly in the embodiment of the utility model is illustrated. It should be noted that the utility model mainly improves the connection between the motor housing and the controller of the motor assembly to improve the heat conduction performance and electromagnetic shielding performance of the connection between the motor housing and the controller; therefore, the drawings of the utility model mainly show the connection structure between the motor housing and the controller.
[0029] Combination Figure 1 and Figure 2 As shown, the motor assembly provided by the embodiment of the utility model includes:
[0030] A cylindrical motor housing 10 and a controller 20 assembled in the motor housing 10, wherein:
[0031] The inner wall of the motor housing 10 includes a first step wall 11 and a second step wall 12 formed in a step shape, and the inner diameter of the first step wall 11 is greater than the inner diameter of the second step wall 12;
[0032] The outer wall of the controller 20 is provided with an annular groove 22, in which a conductive elastomer 24 is embedded. As the controller 20 is assembled into the motor housing 10 from the first step wall 11, the conductive elastomer 24 is pressed between the first step wall 11 and the annular groove 22, and the conductive elastomer 24 is grounded.
[0033] The motor assembly of the utility model adopts a conductive elastomer 24 with both thermal conductivity and electrical conductivity to be pressed between the motor housing 10 and the controller 20, and the conductive elastomer 24 is grounded to achieve the thermal conductivity and electromagnetic shielding performance of the motor assembly. Specifically, the outer wall of the controller 20 is provided with an annular groove 22, so that the conductive elastomer 24 is firmly embedded in the annular groove 22; when the controller 20 is assembled into the motor housing 10, the conductive elastomer 24 is pressed between the motor housing 10 and the controller 20; the inner wall of the motor housing 10 forms a step wall, which can effectively prevent the conductive elastomer 24 from slipping, so that the conductive elastomer 24 is always pressed between the motor housing 10 and the controller 20, and the contact and connection are stable and reliable. Among them, the distance d between the radius of the first step wall 11 of the motor housing 10 and the radius of the second step wall 12 can be set as needed; in addition, the size and deformation capacity of the conductive elastomer 24 can be set as needed to accurately control the gap between the motor housing 10 and the controller 20.
[0034] Therefore, the motor assembly of the utility model realizes thermal conductivity and electromagnetic shielding performance by pressing the conductive elastomer 24 between the motor housing 10 and the controller 20, and has the advantages of simple structure, easy assembly and high stability. It can effectively control the gap between the motor housing 10 and the controller 20, and stably exert the thermal conductivity and electromagnetic shielding performance.
[0035] In some embodiments, the controller 20 is formed into a frustum with a gradually changing outer diameter, and the small end 22 a and the large end 22 b of the controller 20 are successively assembled into the motor housing 10 .
[0036] To simplify the installation of the controller 20 and the motor housing 10, the controller 20 can be processed into a truncated cone with a gradually changing outer diameter. During installation, the small end 22a and the large end 22b are successively assembled into the motor housing 10 to achieve simple installation between the controller 20 and the motor housing 10.
[0037] The included angle θ between the outer wall of the controller 20 and the first step wall 11 of the motor housing 10 can be set as required.
[0038] In some embodiments, the motor housing 10 and the controller 20 are clearance-fitted; the maximum distance between the first step wall 11 and the outer wall of the controller 20 is smaller than the outer diameter of the conductive elastomer 24 .
[0039] During the operation of the motor assembly, the conductive elastomer 24 may fall out of the annular groove 22 due to vibration and other reasons. By designing that the maximum distance between the first step wall 11 and the outer wall of the controller 20 is smaller than the outer diameter of the conductive elastomer 24, the conductive elastomer 24 can be effectively prevented from slipping, ensuring that the conductive elastomer 24 is always pressed between the motor housing 10 and the controller 20, so that the contact and connection are stable and reliable.
[0040] In some embodiments, the minimum distance between the inner wall of the motor housing 10 and the outer wall of the controller 20 is 0.8 mm.
[0041] By setting the size and deformation capacity of the conductive elastomer 24, the gap between the motor housing 10 and the controller 20 can be accurately controlled so that the minimum distance between the inner wall of the motor housing 10 and the outer wall of the controller 20 reaches 0.8 mm, which is beneficial to the thermal conductivity and will not affect rework and repair.
[0042] In other embodiments, the minimum spacing between the motor housing 10 and the controller 20 is not limited to 0.8 mm, and can be controlled within a range of 0.6 mm to 1.0 mm, for example.
[0043] In some embodiments, the first step wall 11 and the second step wall 12 are connected by an inclined surface 13. The inclined surface 13 can support the conductive elastic body 24 when the conductive elastic body 24 escapes from the annular groove 22, prevent the conductive elastic body 24 from sliding off, and ensure that the conductive elastic body 24 is always pressed between the motor housing 10 and the controller 20, so that the contact and connection are stable and reliable.
[0044] In some embodiments, the cross section of the conductive elastic body 24 is formed into a circular ring shape. That is, the conductive elastic body 24 is formed into a hollow structure, so that the conductive elastic body 24 has good deformation ability, so as to be pressed between the motor housing 10 and the controller 20.
[0045] In some embodiments, the conductive elastomer 24 is conductive rubber. The conductive rubber has good electrical and thermal conductivity, and is used as the conductive elastomer 24 and pressed between the motor housing 10 and the controller 20 to achieve good thermal conductivity and electromagnetic shielding performance.
[0046] In some embodiments, the conductive elastomer 24 has one or more of the following performance parameters: resistivity: 0.02 ohm-cm; elongation: 150%; thermal conductivity: 1 W / (m*K).
[0047] By setting the resistivity to 0.02 ohm-cm (ohm·cm), the elongation to 150%, the thermal conductivity to 1W / (m*K) (watt / meter·degree) and other properties, the conductive elastomer 24 can exert good thermal conductivity and electromagnetic shielding performance.
[0048] In some embodiments, the outer wall of the controller 20 is provided with a plurality of circles of annular grooves 22 , and a circle of conductive elastomer 24 is embedded in each circle of the annular grooves 22 .
[0049] For example, two circles of conductive elastic body 24 may be disposed on the outer wall of the controller 20 , but the present invention is not limited thereto.
[0050] The present utility model also provides an electric power steering system, which is configured with a motor assembly as described in any of the above embodiments, and can achieve the following beneficial effects:
[0051] A conductive elastomer 24 having both thermal conductivity and electrical conductivity is pressed between the motor housing 10 and the controller 20, and the conductive elastomer 24 is grounded to achieve good thermal conductivity and electromagnetic shielding performance. Specifically, an annular groove 22 is provided on the outer wall of the controller 20, so that the conductive elastomer 24 is firmly embedded in the annular groove 22; when the controller 20 is assembled into the motor housing 10, the conductive elastomer 24 is pressed between the motor housing 10 and the controller 20; the inner wall of the motor housing 10 forms a step wall, which can effectively prevent the conductive elastomer 24 from slipping, so that the conductive elastomer 24 is always pressed between the motor housing 10 and the controller 20, and the contact and connection are stable and reliable. Among them, the distance d between the radius of the first step wall 11 of the motor housing 10 and the radius of the second step wall 12 can be set as needed; in addition, the size and deformation capacity of the conductive elastomer 24 can be set as needed to accurately control the gap between the motor housing 10 and the controller 20.
[0052] In this way, thermal conductivity and electromagnetic shielding performance are achieved by pressing the conductive elastomer 24 between the motor housing 10 and the controller 20, which has the advantages of simple structure, easy assembly and high stability. It can effectively control the gap between the motor housing 10 and the controller 20 and stably exert thermal conductivity and electromagnetic shielding performance.
[0053] The above contents are further detailed descriptions of the present invention in combination with specific preferred implementations, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.
Claims
1. A motor assembly, comprising a cylindrical motor housing and a controller assembled in the motor housing, characterized in that: The inner wall of the motor housing includes a first step wall and a second step wall formed in a step shape, and the inner diameter of the first step wall is greater than the inner diameter of the second step wall; The outer wall of the controller is provided with an annular groove, in which a conductive elastomer is embedded. As the controller is assembled into the motor housing from the first step wall, the conductive elastomer is pressed between the first step wall and the annular groove, and the conductive elastomer is grounded.
2. The motor assembly according to claim 1, characterized in that: The controller is formed into a truncated cone with a gradually changing outer diameter, and the small end and the large end of the controller are successively assembled into the motor housing.
3. The motor assembly according to claim 1, characterized in that: There is clearance fit between the motor housing and the controller; The maximum distance between the first step wall and the outer wall of the controller is smaller than the outer diameter of the conductive elastic body.
4. The motor assembly according to claim 3, characterized in that: The minimum distance between the inner wall of the motor housing and the outer wall of the controller is 0.8 mm.
5. The motor assembly according to claim 1, characterized in that: The first step wall and the second step wall are connected via an inclined surface.
6. The motor assembly according to claim 1, characterized in that: The conductive elastic body has a circular cross-section.
7. The motor assembly according to claim 1, characterized in that: The conductive elastomer is conductive rubber.
8. The motor assembly according to claim 1, characterized in that: The conductive elastomer has one or more of the following performance parameters: Resistivity: 0.02ohm-cm; Elongation: 150%; Thermal conductivity: 1W / (m*K).
9. The motor assembly according to any one of claims 1 to 8, characterized in that: The outer wall of the controller is provided with a plurality of circles of the annular grooves, and a circle of the conductive elastic body is embedded in each circle of the annular grooves.
10. An electric power steering system, characterized in that: The electric power steering system is equipped with a motor assembly as described in any one of claims 1-9.