Mounting structure of electric power steering system

Abstract

The utility model provides an electric power steering system mounting structure which comprises a shell, the shell comprises at least one mounting part, each mounting part is provided with a mounting hole, at least one rubber bushing is mounted in each mounting hole, and the rubber bushings are arranged in the mounting holes. The rubber bushing comprises a metal framework located in the rubber bushing and a rubber sleeve arranged outside the metal framework in a sleeving mode, a connecting hole is formed in the metal framework, the inner wall of the mounting hole comprises a matching part and at least one stopping part, and the stopping part protrudes towards the inner side relative to the matching part. And the inner diameter of the mounting hole corresponding to the stop part is smaller than the inner diameter of the mounting hole corresponding to the matching part. According to the electric power steering system, the matching stability of the rubber bushing and the mounting part is improved, so that the assembling stability of the electric power steering system is improved.

Description

Technical Field

[0001] The present application relates to the technical field of electric power steering systems, and in particular to an installation structure of an electric power steering system. Background Art

[0002] Electric Power Steering (EPS) is a power steering system that directly relies on a motor to provide auxiliary torque. When the housing of the electric power steering system is installed on a vehicle, a mounting hole that matches the bolt is provided in the housing, and a rubber bushing is provided in the mounting hole. In order to improve the matching stability of the rubber bushing in the mounting hole, it is necessary to strictly control the processing accuracy and roughness of the inner wall of the mounting hole, and the precision requirements for the processing technology are very high. The existing processing method of the mounting hole is generally to perform a rough machining first, and then perform a fine machining with high precision requirements, and the requirements for the processing technology are very high. However, during use, relying solely on the control of the processing accuracy and roughness of the inner wall of the mounting hole cannot well maintain the position of the rubber bushing in the mounting hole. The rubber bushing may pop out of the mounting hole, and it is also easy to be pulled out of the mounting hole when subjected to external force after assembly. Especially for some rubber bushings with a small height and low rigidity, the possibility of positional displacement between the rubber bushing and the mounting hole or even being pulled out of the mounting hole is greatly increased, which seriously affects the matching stability of the rubber bushing and the mounting hole. Utility Model Content

[0003] In view of the problems in the prior art, the purpose of the present application is to provide an electric power steering system mounting structure to improve the matching stability between the rubber bushing and the mounting portion, thereby improving the assembly stability of the electric power steering system.

[0004] An embodiment of the present application provides an electric power steering system mounting structure, including a shell, the shell including at least one mounting portion, each of the mounting portions being provided with a mounting hole, at least one rubber bushing being installed in the mounting hole, the rubber bushing including an internal metal frame and a rubber sleeve sleeved on the outside of the metal frame, a connecting hole being provided inside the metal frame, the inner wall of the mounting hole including a matching portion and at least one stop portion, the stop portion protruding inwardly relative to the matching portion so that the inner diameter of the mounting hole corresponding to the stop portion is smaller than the inner diameter of the mounting hole corresponding to the matching portion.

[0005] In some embodiments, a stop portion is respectively disposed at two axial ends of the mounting hole, and the matching portion is disposed between the stop portions at the two ends.

[0006] In some embodiments, transition surfaces are formed at the connection positions of the stop portion and the matching portion to avoid forming sharp surfaces at the connection positions of the stop portion and the matching portion to damage the rubber bushing, and the transition surfaces are rounded surfaces or chamfered surfaces.

[0007] In some embodiments, the upper side of the stop portion located at the upper end of the mounting hole forms a transition surface extending to the upper surface of the mounting portion, and the lower side of the stop portion located at the lower end of the mounting hole forms a transition surface extending to the lower surface of the mounting portion, and the transition surface is a rounded surface or a chamfered surface.

[0008] In some embodiments, a groove is further provided on the outer side of the rubber bushing, and the stopper is at least partially located in the groove.

[0009] In some embodiments, the stop portion is a stop ring extending circumferentially along the inner wall of the mounting hole.

[0010] In some embodiments, the mounting holes are through holes, and two rubber bushings are disposed in each of the mounting holes, and the two rubber bushings are arranged along the axial direction of the mounting holes.

[0011] In some embodiments, the rubber bushing includes a main body and a flange portion connected to one end of the main body, the outer diameter of the flange portion is larger than the outer diameter of the main body, the flange portions of the two rubber bushings protrude from the outside of the axial ends of the mounting hole respectively, and the main bodies of the two rubber bushings enter the interior of the mounting hole from the two ends of the mounting hole respectively.

[0012] In some embodiments, the maximum height of the stop portion protruding inward relative to the mounting portion is 0.5 mm to 1.5 mm, and the axial height of the stop portion is 5 mm to 10 mm.

[0013] In some embodiments, the connecting hole of the rubber bushing is a threaded hole or a through hole with a smooth inner wall.

[0014] The electric power steering system installation structure provided in this application has the following advantages:

[0015] The electric power steering system mounting structure of the present application is used to mount the housing of the electric power steering system on the subframe of the vehicle. A rubber bushing for shock absorption is provided in the mounting hole of the housing, and a stopper is provided in the mounting hole to prevent the rubber bushing from being offset from the mounting hole and effectively prevent the rubber bushing from being pulled out by external force during use, thereby improving the matching stability between the rubber bushing and the mounting portion, thereby improving the assembly stability of the electric power steering system, and the rubber bushing can play a good role in shock absorption and noise reduction; and, since the stopper can well maintain the position of the rubber bushing, the requirement for the roughness control accuracy of the inner wall is reduced, and the difficulty of the processing technology is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings.

[0017] Figure 1 is a cross-sectional view of a mounting portion of a housing according to an embodiment of the present application;

[0018] Figure 2 This is a schematic diagram of the structure of the shell and the rubber bushing in accordance with an embodiment of the present application;

[0019] Figure 3 is a schematic structural diagram of a rubber bushing according to an embodiment of the present application;

[0020] Figure 4 is a top view of a rubber bushing according to an embodiment of the present application;

[0021] Figure 5 It is a cross-sectional view of a rubber bushing according to an embodiment of the present application.

[0022] Reference numerals:

[0023] 1 Shell 21 Metal frame

[0024] 10 Mounting part 22 Rubber sleeve

[0025] 11 Mounting hole 23 Main body

[0026] 111 stopper 24 flange

[0027] 112 matching portion 25 connection hole

[0028] 2 Rubber bushing 26 groove DETAILED DESCRIPTION

[0029] 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; on the contrary, these embodiments are provided so that the present application will be comprehensive and complete, and the concept of the example embodiments will be fully conveyed to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their repeated descriptions will be omitted. "Or" and "or" in the specification may both mean "and" or "or". Although the terms "above", "below", "between", etc. may be used in this specification to describe different exemplary features and elements of the present application, these terms are used herein only for convenience, such as according to the directions of the examples described in the accompanying drawings. Nothing in this specification should be construed as requiring a specific three-dimensional orientation of the structure to fall within the scope of the present application.

[0030] In order to solve the technical problems of the prior art, an embodiment of the present application provides an electric power steering system mounting structure for mounting the housing of the electric power steering system on the subframe of a vehicle. The mounting structure includes a housing, and the housing includes at least one mounting portion, each of the mounting portions is provided with a mounting hole, and at least one rubber bushing for shock absorption is installed in the mounting hole. The rubber bushing includes an internal metal frame and a rubber sleeve sleeved on the outside of the metal frame, and a connecting hole is provided inside the metal frame. The electric power steering system can be mounted on the subframe of the vehicle by means of a fixing member inserted into the connecting hole. The inner wall of the mounting hole includes a matching portion and at least one stop portion, and the stop portion protrudes inward relative to the matching portion, so that the inner diameter of the mounting hole corresponding to the stop portion is smaller than the inner diameter of the mounting hole corresponding to the matching portion. The present application can effectively prevent the rubber bushing from being offset from the mounting hole by setting the stopper, and effectively prevent the rubber bushing from being pulled out by external force during use, thereby improving the matching stability between the rubber bushing and the mounting portion, thereby improving the assembly stability of the electric power steering system; and, because the stopper can well maintain the position of the rubber bushing, the requirement for the roughness control accuracy of the inner wall is reduced, thereby reducing the difficulty of the processing technology.

[0031] The specific structure of the electric power steering system installation structure in one embodiment is described in detail below in conjunction with the accompanying drawings. It should be understood that the accompanying drawings and the following description are only examples and are not intended to limit the scope of protection of this application.

[0032] like Figures 1 to 5 As shown, in one embodiment, the electric power steering system mounting structure includes a housing 1, and the housing 1 includes at least one mounting portion 10, each of the mounting portions 10 is provided with a mounting hole 11, and at least one rubber bushing 2 for shock absorption is installed in the mounting hole 11, and the outer wall of the rubber bushing 2 is in contact with the inner wall of the mounting hole 11. The number of the mounting portions 10 and the number of the rubber bushings 2 can be selected as needed. For example, the housing 1 can be provided with three mounting portions 10, or fewer or more mounting portions 10, and each mounting portion 10 is provided with a mounting hole 11. One, two or more rubber bushings 2 can be installed in each mounting hole 11. In this embodiment, two rubber bushings 2 are provided in each mounting hole 11 for illustration, but the present application is not limited thereto.

[0033] The rubber bushing 2 includes a metal frame 21 located inside and a rubber sleeve 22 sleeved on the outside of the metal frame 21, and a connecting hole 25 is opened inside the metal frame 21. The electric power steering system can be installed on the subframe of the vehicle by means of a fixing piece inserted into the connecting hole 25. In one embodiment, the fixing piece is a bolt, and the connecting hole 25 is a through hole with a smooth inner wall. After the fixing piece passes through the hole on the subframe of the vehicle and the connecting hole 25, a nut is used to fix one end of the bolt. In another embodiment, the fixing piece is a bolt, and the connecting hole 25 is a bolt hole. The inner wall of the connecting hole 25 is provided with an internal thread that matches the external thread of the bolt. The fixing piece passes through the hole on the subframe of the vehicle and is screwed to the bolt hole.

[0034] like Figure 1 As shown, the inner wall of the mounting hole 11 includes a matching portion 112 and at least one stopper 111, and the stopper 111 protrudes inward relative to the matching portion 112, so that the inner diameter of the mounting hole 11 corresponding to the stopper 111 is smaller than the inner diameter of the mounting hole 11 corresponding to the matching portion 112. The stopper 111 can effectively prevent the rubber bushing 2 from being offset from the mounting hole 11, and effectively prevent the rubber bushing 2 from being pulled out by external force during use, thereby improving the matching stability between the rubber bushing 2 and the mounting portion 10, thereby improving the assembly stability of the electric power steering system, so that it can remain stable during transportation and use. In addition, since the stopper 111 can well maintain the position of the rubber bushing 2, the requirements for the roughness control accuracy of the inner wall are reduced, and the difficulty of the processing technology is reduced.

[0035] In this embodiment, a stopper 111 is respectively provided at both axial ends of the mounting hole 11, and the matching portion 112 is provided between the stopper 111 at both ends, so that after the rubber bushing 2 is installed in the mounting hole 11, the upper stopper ring can prevent the rubber bushing 2 from being forced out from above, and the lower stopper ring can prevent the rubber bushing 2 from being forced out from below. The stopper 111 is a stopper ring extending circumferentially along the inner wall of the mounting hole 11, providing a circumferentially uniformly distributed blocking force to the rubber bushing 2. Therefore, this embodiment can effectively prevent the rubber bushing 2 from being pulled out after the rubber bushing 2 is installed on the housing 1 by respectively providing a stopper ring at both axial ends of the mounting hole 11. Figures 3 to 5 As shown, a groove 26 is further provided on the outer side of the rubber bushing 2, and the stopper 111 is at least partially located in the groove 26. In this embodiment, the groove 26 is an annular groove adapted to the shape of the stop ring.

[0036] In this embodiment, transition surfaces are formed at the connection positions of the stopper 111 and the matching portion 112, and the transition surfaces are rounded surfaces or chamfered surfaces. The upper side of the stopper 111 located at the upper end of the mounting hole 11 forms a transition surface extending to the upper surface of the mounting portion 10, and the lower side of the stopper 111 located at the lower end of the mounting hole 11 forms a transition surface extending to the lower surface of the mounting portion 10, and the transition surface is a rounded surface or a chamfered surface. By providing a transition surface at the portion where the inner diameter of the inner wall of the mounting hole 11 changes, there is a smooth transition on both the upper and lower sides of the stopper 111, thereby preventing the rubber bushing 2 from being torn during assembly and use.

[0037] like Figure 1 As shown, in this embodiment, the minimum inner diameter of the stopper 111 (the highest position of the stopper 111) is d2, the inner diameter of the matching portion 112 is d1, and the maximum height of the stopper 111 protruding inward relative to the mounting portion 10 is (d1-d2), which can be 0.5mm-1.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, etc. The total height of the mounting hole 11 is h1, the height of the matching portion 112 is h2, and the axial height of a single stopper 111 is (h1-h2) / 2, which can be 5mm-10mm, for example, 5.5mm, 6mm, 7mm, 8mm, etc. This embodiment reasonably designs the size of the stop portion 111 and the size ratio of the stop portion 111 to the mounting hole 11, thereby ensuring that the stop portion 111 has a good stopping effect on the rubber bushing 2, thereby preventing the stop portion 111 from being too small to form an effective limiting effect, and preventing the stop portion 111 from being too large to cause a great obstacle to the installation of the rubber bushing 2, and preventing the stop portion 111 from squeezing the rubber bushing 2 too much to damage the rubber bushing 2.

[0038] like Figure 2 and Figure 3 As shown, in this embodiment, the mounting hole 11 is a through hole, and two rubber bushings 2 are arranged in each mounting hole 11, and the two rubber bushings 2 are arranged along the axial direction of the mounting hole 11. The rubber bushing 2 includes a body portion 23 and a flange portion 24 connected to one end of the body portion 23, and the outer diameter of the flange portion 24 is larger than the outer diameter of the body portion 23. The flange portions 24 of the two rubber bushings 2 protrude from the outside of the axial ends of the mounting hole 11, respectively, and the body portions 23 of the two rubber bushings 2 enter the inside of the mounting hole 11 from the two ends of the mounting hole 11, respectively. The number, shape and arrangement of the rubber bushings 2 here are only examples, and are not intended to limit the scope of protection of this application.

[0039] The use of the installation structure of this embodiment will not change the assembly process of the shell 1 and the rubber bushing 2 on the existing production line, and the existing number of processing times for the mounting hole 11 of the shell 1 does not need to be changed. As described in the background technology, the existing processing method of the mounting hole 11 is generally to perform a rough processing first, and then perform a fine processing with very high precision requirements, which has very high requirements on the processing technology. The processing of the mounting hole 11 of the present application is also divided into two steps: first, a hole with an inner diameter of d2 is processed, and then the part with an inner diameter of d1 is further processed inside the hole to form a matching portion 112, and the stopper portion 111 with an inner diameter of d2 is still retained on both sides of the matching portion 112. Therefore, the number of processing times of the mounting hole 11 will not increase, and the cycle time of the shell 1 processing will not increase. In addition, when processing the hole, there is no need to strictly control the roughness and processing tolerance, which reduces the requirements for the processing technology.

[0040] By testing the existing installation structure and the installation structure of the present application respectively, the beneficial effects of the installation structure of the present application can be verified. Specifically, when the existing matching mode of the housing 1 and the rubber bushing 2 is adopted, when the operating force of 354N, 316N, 342N, and 299N is applied, the rubber bushing 2 will be pulled out from the mounting hole 11 of the housing 1 by the external force. When the matching mode of the housing 1 and the rubber bushing 2 of the present application is adopted, when the operating force of 826N, 924N, 997N, and 954N is applied, the rubber bushing 2 is not pulled out, that is, the installation structure of the present application improves the stability of the rubber bushing 2 and the housing 1, and avoids the rubber bushing 2 from being accidentally pulled out. When the durability test of the installation structure of the present application is carried out, the conditions of the durability test are: the force applied in the X / Y direction is ±5300N, the force applied in the Z direction is ±2500N, the frequency is 1±0.1Hz, and 200000 cycles. After the test, the rubber had no cracks and the loss of stiffness was less than 20% (the stiffness before the test was: X / Y: 7738N / mm, Z direction: 1552N / mm, the stiffness after the test was: X / Y: 7164N / mm, Z direction: 1468N / mm), that is, the installation structure of the present application can meet the requirements of durable use.

[0041] The above content is a further detailed description of the present application in combination with specific preferred implementation methods, and it cannot be determined that the specific implementation of the present application is limited to these descriptions. For ordinary technicians in the technical field to which the present application belongs, several simple deductions or substitutions can be made without departing from the concept of the present application, which should be deemed to fall within the scope of protection of the present application.

Claims

1. An electric power steering system installation structure, characterized in that: The invention comprises a shell, wherein the shell comprises at least one mounting part, each of the mounting parts is provided with a mounting hole, at least one rubber bushing is installed in the mounting hole, the rubber bushing comprises a metal frame located inside and a rubber sleeve sleeved on the outside of the metal frame, a connecting hole is provided inside the metal frame, the inner wall of the mounting hole comprises a matching part and at least one stop part, the stop part protrudes inwardly relative to the matching part, so that the inner diameter of the mounting hole corresponding to the stop part is smaller than the inner diameter of the mounting hole corresponding to the matching part.

2. The electric power steering system installation structure according to claim 1, characterized in that: The two axial ends of the mounting hole are respectively provided with a stopper, and the matching portion is arranged between the stoppers at the two ends.

3. The electric power steering system installation structure according to claim 2, characterized in that: Transition surfaces are formed at the connection positions of the stop portion and the matching portion, respectively, and the transition surfaces are rounded surfaces or chamfered surfaces.

4. The electric power steering system installation structure according to claim 2, characterized in that: The upper side of the stop portion located at the upper end of the mounting hole forms a transition surface extending to the upper surface of the mounting portion, and the lower side of the stop portion located at the lower end of the mounting hole forms a transition surface extending to the lower surface of the mounting portion, and the transition surface is a rounded surface or a chamfered surface.

5. The electric power steering system installation structure according to claim 1, characterized in that: The outer side of the rubber bushing is also provided with a groove, and the stopper is at least partially located in the groove.

6. The electric power steering system installation structure according to claim 1, characterized in that: The stopper is a stopper ring extending circumferentially along the inner wall of the mounting hole.

7. The electric power steering system installation structure according to claim 1, characterized in that: The mounting holes are through holes, and two rubber bushings are arranged in each mounting hole. The two rubber bushings are arranged along the axial direction of the mounting hole.

8. The electric power steering system installation structure according to claim 7, characterized in that: The rubber bushing includes a main body and a flange connected to one end of the main body, the outer diameter of the flange is larger than the outer diameter of the main body, the flanges of the two rubber bushings protrude from the outside of the axial ends of the mounting hole respectively, and the main bodies of the two rubber bushings enter the interior of the mounting hole from the two ends of the mounting hole respectively.

9. The electric power steering system installation structure according to claim 1, characterized in that: The maximum height of the stopper protruding inward relative to the mounting portion is 0.5 mm to 1.5 mm, and the axial height of the stopper is 5 mm to 10 mm.

10. The electric power steering system installation structure according to claim 1, characterized in that: The connecting hole of the rubber bushing is a threaded hole or a through hole with a smooth inner wall.

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