Rps magnet assembly, rps magnet assembly press-in mechanism and motor

Abstract

The utility model relates to a kind of RPS magnet assembly, RPS magnet assembly press-in mechanism and motor, wherein RPS magnet assembly includes the shaft body for and motor shaft cooperation hole tight cooperation one end, the other end of shaft body is provided with magnet accommodating cavity, magnet accommodating cavity is integrally formed with shaft body, magnet accommodating cavity is provided with the RPS magnet rotating with shaft body.In the process of using press-in mechanism and press into to motor shaft cooperation hole, pressure is applied in the top of magnet accommodating cavity, avoids the RPS magnet in magnet accommodating cavity, so RPS magnet is not pressed to crack due to the problem of deformation expansion caused by shaft body being pressed after.And because shaft body and magnet accommodating cavity integrally formed, therefore simplify assembly process, improve the stability of product.

Description

Technical Field

[0001] This utility model belongs to the field of motor technology, specifically relating to an RPS magnet assembly, an RPS magnet assembly pressing mechanism, and a motor. Background Technology

[0002] In an EPS steering system, the Rotor Position Sensor (RPS) consists of an RPS magnet and an RPS chip, such as... Figure 1 As shown, the RPS magnet 3 is sleeved on the shaft 2 and rotates with the shaft 2. The RPS chip senses the change in the magnetic field angle of the RPS magnet 3, thereby obtaining the position of the motor rotor through the internal algorithm of the RPS chip. The shaft 2 is assembled into the motor shaft mating hole on the motor shaft. The shaft 2 and the motor shaft mating hole are tightly fitted. Therefore, during installation, the shaft 2 needs to be pressed into the motor shaft mating hole by external force. However, the shaft 2 may deform and expand after being subjected to a large external force. The deformation and expansion of the shaft may cause the RPS magnet to crack. For this reason, the prior art has an outer cover on the outside of the RPS magnet 3, such as... Figure 2 As shown, the outer cover 4 improves the situation of RPS magnets being cracked to some extent.

[0003] To further mitigate the potential problem of RPS magnets cracking during the pressing process, the existing technology incorporates a gasket 7 (such as...) between the RPS magnet 3 and the outer casing 4. Figure 3 As shown, the strength of the RPS magnet 3 is increased by adding shims 7. Although the strength of the RPS magnet 3 is improved by adding shims 7, it cannot overcome the problem of the RPS magnet cracking due to shaft deformation and expansion in the prior art. Furthermore, the increased processing technology leads to reduced product reliability and significantly increased product cost. Utility Model Content

[0004] In order to solve all or part of the above problems, the present invention aims to provide an RPS magnet assembly, an RPS magnet assembly pressing mechanism and a motor, wherein the RPS magnet assembly includes an integrally formed shaft and a magnet receiving cavity, and the RPS magnet is injection molded in the magnet receiving cavity.

[0005] According to one aspect of the present invention, an RPS magnet assembly is provided, comprising a shaft at one end for tightly fitting with a motor shaft mating hole, and a magnet receiving cavity at the other end of the shaft, the magnet receiving cavity being integrally formed with the shaft, and an RPS magnet being disposed in the magnet receiving cavity and rotating with the shaft.

[0006] Furthermore, an annular groove is provided on the inner wall of the magnet receiving cavity. When the RPS magnet is filled into the magnet receiving cavity by injection molding, a flange that cooperates with the annular groove is formed to limit the RPS magnet along the axial direction of the shaft.

[0007] Furthermore, at least one anti-rotation groove is provided on the inner sidewall of the magnet receiving cavity. When the RPS magnet is filled into the magnet receiving cavity by injection molding, a mating block is formed that cooperates with the anti-rotation groove so that the RPS magnet rotates with the shaft.

[0008] Furthermore, the inner side of the bottom wall of the magnet receiving cavity is provided with at least one anti-rotation groove. When the RPS magnet is filled into the magnet receiving cavity by injection molding, a mating block that cooperates with the anti-rotation groove is formed so that the RPS magnet rotates with the shaft.

[0009] Furthermore, at least one positioning notch is provided on the outer wall of the magnet receiving cavity, and the axis of the positioning notch is parallel to the axis of the shaft.

[0010] Furthermore, there are three positioning notches. Of the three positioning notches, one corresponds to the N pole of the RPS magnet, another corresponds to the S pole of the RPS magnet, and the third is located on the perpendicular line connecting the N pole and the S pole of the RPS magnet.

[0011] Furthermore, the magnet receiving cavity includes a cavity wall and a bottom wall, one side of the bottom wall is connected to the shaft, the cavity wall is connected around the bottom wall, and the cavity wall extends away from the shaft along the axis of the shaft.

[0012] Furthermore, the cavity wall and the bottom wall form a tapered structure with the bottom wall as the smaller end, and the radius of the bottom wall is greater than the radius of the shaft.

[0013] According to another aspect of the present invention, an RPS magnet assembly pressing mechanism is provided, the pressing mechanism being used to press the RPS magnet assembly described in any of the above into the motor shaft mating hole, the pressing mechanism including a pressing head, the pressing head mating with the side of the magnet receiving cavity away from the shaft body; the pressing head having an avoidance groove for avoiding the RPS magnet.

[0014] According to another aspect of the present invention, an electric motor is provided, wherein the electric motor employs the RPS magnet assembly described in any of the above claims.

[0015] As can be seen from the above technical solution, the RPS magnet assembly, RPS magnet assembly pressing mechanism, and motor provided by this utility model have the following beneficial effects: The RPS magnet assembly of this utility model includes an integrally formed shaft and a magnet receiving cavity. The RPS magnet is injection molded in the magnet receiving cavity. Therefore, during the process of pressing the shaft into the motor shaft mating hole using the pressing mechanism, the problem of the RPS magnet being cracked due to the deformation and expansion of the shaft after being pressed will not occur. Furthermore, since the shaft and the magnet receiving cavity are integrally formed, the assembly process is simplified and the stability of the product is improved. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of the connection between the shaft and the RPS magnet in the prior art; Figure 2 This is a cross-sectional view of another type of shaft connection to an RPS magnet in the prior art; Figure 3 A cross-sectional view of the connection between the shaft and the RPS magnet after the shims have been laid in the prior art; Figure 4 This is a cross-sectional view of an RPS magnet assembly according to an embodiment of the present utility model; Figure 5 This is a cross-sectional view of the shaft and magnet receiving cavity portion according to an embodiment of the present utility model; Figure 6 This is a schematic diagram of an RPS magnet assembly according to an embodiment of the present invention; Figure 7 This is a top view of an RPS magnet assembly according to an embodiment of the present utility model; Figure 8 This is a cross-sectional view of the RPS magnet assembly of this utility model being pressed into the motor shaft mating hole by a pressing mechanism. Figure 9 This is a schematic diagram of the motor according to an embodiment of the present utility model; The attached figures are labeled as follows: pressure head 1, clearance groove 11, shaft 2, magnet receiving cavity 20, bottom wall 21, cavity wall 22, annular groove 221, positioning notch 222, anti-rotation groove 223, RPS magnet 3, outer cover 4, motor shaft 5, motor shaft mating hole 51, motor body 6, gasket 7. Detailed Implementation

[0017] To better understand the purpose, structure, and function of this utility model, the following description, in conjunction with the accompanying drawings, provides a more detailed account of an RPS magnet assembly, an RPS magnet assembly pressing mechanism, and a motor.

[0018] This utility model embodiment proposes an RPS magnet assembly, such as Figures 4-6 , Figure 8As shown, the RPS magnet assembly includes a shaft 2 with one end for tightly engaging with the motor shaft mating hole 51 on the motor shaft 5, and a magnet receiving cavity 20 at the other end of the shaft 2. The magnet receiving cavity 20 is integrally formed with the shaft 2, and an RPS magnet 3 that rotates with the shaft 2 is disposed inside the magnet receiving cavity 20.

[0019] Specifically, the RPS magnet assembly in this embodiment includes an integrally formed shaft 2 and a magnet receiving cavity 20. The shaft 2 is used to fit tightly with the motor shaft mating hole 51 on the motor shaft 5, and the magnet receiving cavity 20 is used to house the RPS magnet 3. The RPS magnet 3 is formed in the magnet receiving cavity 20 by injection molding. In specific implementation, for example, magnetic powder and PPS material are mixed, or magnetic powder and PA material are mixed, and the mixed material is sprayed into the magnet receiving cavity 20. After cooling and molding, the RPS magnet 3 is formed. Secondly, the RPS magnet 3 should have N poles and S poles. Thirdly, in order to avoid the shaft 2 affecting the magnetic field of the RPS magnet 3, the shaft 2 is made of a non-magnetic metal, such as brass, aluminum, stainless steel, etc.

[0020] Secondly, in this embodiment, the magnet receiving cavity 20 and the shaft 2 are integrally formed, compared to Figure 2 and Figure 3 Compared to existing technologies, this embodiment does not require installing an outer cover on the RPS magnet, fixing the outer cover to the shaft, or laying shims inside the RPS magnet to reinforce it (for...). Figure 3 In other words, the configuration method in this embodiment simplifies the assembly process, saves assembly time, and reduces assembly costs.

[0021] Furthermore, the structure of this embodiment can be manufactured by CNC lathe. Specifically, after blanking, the shaft 2 and the magnet receiving cavity 20 can be obtained by machining.

[0022] Finally, during the process of pressing the shaft 2 of this embodiment into the motor shaft mating hole 51 using the pressing mechanism, the pressing mechanism acts on the top of the side wall of the magnet receiving cavity 20 around the RPS magnet 3, and the shaft 2 is pressed into the motor shaft mating hole 51 through the magnet receiving cavity 20. Therefore, compared with the prior art, this embodiment solves the problem of the RPS magnet 3 being cracked due to the deformation and expansion of the shaft 2.

[0023] In one embodiment, such as Figures 4-6 , Figure 8 As shown, an annular groove 221 is provided on the inner side wall of the magnet receiving cavity 20. When the RPS magnet 3 is filled into the magnet receiving cavity 20 by injection molding, a flange that cooperates with the annular groove 221 is formed to limit the RPS magnet 3 along the axial direction of the shaft 2.

[0024] The annular groove 221 can limit the displacement of the RPS magnet 3 along the axial direction of the shaft 2. Correspondingly, the injection-molded RPS magnet 3 has a flange that mates with the annular groove 221. The mating of the flange and the annular groove 221 prevents relative movement between the RPS magnet 3 and the magnet receiving cavity 20 along the axial direction of the shaft 2.

[0025] Secondly, in implementation, an annular protrusion can be used instead of the annular slot 221. The annular protrusion is set on the inner wall of the magnet receiving cavity 20, and a corresponding mating groove is formed on the RPS magnet 3 injection molded in the magnet receiving cavity 20 to cooperate with the annular protrusion.

[0026] Secondly, regarding the case where an annular groove 221 is provided on the inner wall of the magnet receiving cavity 20, after the CNC lathe turns out the magnet receiving cavity 20, the annular groove 221 can be turned on the inner wall of the magnet receiving cavity 20; regarding the case where an annular protrusion is provided on the inner wall of the magnet receiving cavity 20, after the CNC lathe turns out the magnet receiving cavity 20, the inner walls of the magnet receiving cavity 20 on both sides of the annular protrusion are machined to form the annular protrusion.

[0027] In one embodiment, such as Figure 5 , Figure 6 As shown, at least one anti-rotation groove 223 is provided on the inner side wall of the magnet receiving cavity 20. When the RPS magnet 3 is filled into the magnet receiving cavity 20 by injection molding, a mating block is formed that cooperates with the anti-rotation groove 223 so that the RPS magnet 3 rotates with the shaft 2.

[0028] In this embodiment, the cooperation between the mating block and the anti-rotation groove 223 allows the RPS magnet 3 to rotate with the shaft 2, preventing relative rotation between the RPS magnet 3 and the magnet receiving cavity 20 due to looseness. This ensures the accuracy of the magnetic field angle of the RPS magnet 3 sensed by the RPS chip. Specifically, multiple anti-rotation grooves 223 can be provided, for example, more than three. The specific shape of the anti-rotation groove can be, for example, an arc, a polygon, or any other arbitrary shape.

[0029] Secondly, in implementation, anti-rotation protrusions can be used instead of anti-rotation grooves 223. The anti-rotation protrusions are correspondingly set on the inner wall of the magnet receiving cavity 20, and the RPS magnet 3, which is injection molded in the magnet receiving cavity 20, has corresponding grooves that cooperate with the anti-rotation protrusions.

[0030] Finally, for the case where an annular groove 221 and an anti-rotation groove 223 are provided on the inner wall of the magnet receiving cavity 20, after the aforementioned annular groove 221 is machined using a CNC lathe, several grooves are milled again on the upper or lower wall thickness of the annular groove 221 to serve as the anti-rotation groove 223 in this embodiment.

[0031] As an alternative, at least one anti-rotation groove is provided on the inner side of the bottom wall of the magnet receiving cavity 20. When the RPS magnet 3 is filled into the magnet receiving cavity 20 by injection molding, a mating block that cooperates with the anti-rotation groove is formed so that the RPS magnet 3 rotates with the shaft 2.

[0032] In this alternative, the anti-rotation groove is located on the inner side of the bottom wall of the magnet receiving cavity 20, thereby improving the strength of the magnet receiving cavity 20. The anti-rotation groove is, for example, a non-cylindrical structure such as an arc or a polygon.

[0033] In one embodiment, such as Figure 4 , Figure 7 As shown, at least one positioning notch 222 is provided on the outer wall of the magnet receiving cavity 20, and the axis of the positioning notch 222 is parallel to the axis of the shaft 2. The positioning notch 222 is provided to facilitate positioning during the assembly process, for example, to align the N pole or S pole of the RPS chip with the RPS magnet 3 in the magnet receiving cavity 20 during the assembly process.

[0034] In one embodiment, such as Figure 7 As shown, there are three positioning notches 222. Among the three positioning notches 222, one corresponds to the N pole of the RPS magnet 3, another corresponds to the S pole of the RPS magnet 3, and the third is set on the perpendicular line connecting the N pole and the S pole of the RPS magnet 3.

[0035] In one specific embodiment, such as Figure 5 , Figure 8 As shown, the magnet receiving cavity 20 includes a cavity wall 22 and a bottom wall 21. One side of the bottom wall 21 is connected to the shaft 2, and the cavity wall 22 is connected around the bottom wall 21. The cavity wall 22 extends away from the shaft 2 along the axis of the shaft 2.

[0036] In this embodiment, the magnet receiving cavity 20 includes a cavity wall 22 and a bottom wall 21. The cavity wall 22 extends away from the axis of the shaft 2, so that the magnet receiving cavity 20 has a depth that can accommodate the RPS magnet 3.

[0037] The aforementioned annular groove 221 is provided on the inner side wall of the cavity wall 22, and the anti-rotation groove can be provided on the inner side wall of the cavity wall 22 or the inner side wall of the bottom wall 21, depending on the actual situation. The aforementioned positioning notch 222 is provided on the outer side wall of the cavity wall 22.

[0038] In one embodiment, the cavity wall 22 and the bottom wall 21 form a tapered structure with the bottom wall 21 as the smaller end, and the radius of the bottom wall 21 is greater than the radius of the shaft 2.

[0039] Specifically, the cavity wall 22 and the bottom wall 21 form a tapered structure with the bottom wall 21 at the smaller end, and the radius of the bottom wall 21 is greater than the radius of the shaft 2. This makes the radius of the cavity wall of the magnet receiving cavity 20 in the direction perpendicular to the axis of the shaft 2 greater than the radius of the shaft. Therefore, for the same volume of RPS magnet 3, the depth of the magnet receiving cavity 20 can be reduced. Furthermore, the larger the radius of the cavity wall of the magnet receiving cavity 20, the more dispersed the force applied by the pressure head to the top of the cavity wall of the magnet receiving cavity 20 is, thereby improving the overall compressive strength of the RPS magnet assembly.

[0040] Taking a motor shaft mating hole of the same size as an example, comparing the case where the pressing mechanism acts on the shaft in the prior art with the case where the pressing mechanism acts on the magnet receiving cavity 20 in this embodiment: Since the radius of the cavity wall of the magnet receiving cavity 20 is larger than the radius of the shaft in the direction perpendicular to the shaft axis, for the same pressing deviation (the deviation between the axis where the pressing position is located and the actual axis), the relative error of the magnet receiving cavity 20 with a larger outer diameter is smaller.

[0041] Compared to cases with the same relative error, the pressing deviation of this embodiment is significantly greater than that of the prior art. When the pressing deviation of this embodiment is large, its presence is visually apparent, allowing for timely adjustment to reduce it. Therefore, the structure of this embodiment has an advantage in terms of error compared to the structure of the prior art.

[0042] In summary, the positional accuracy requirement of the RPS magnet assembly in this embodiment on the magnet receiving cavity 20 is lower than that of the prior art during the pressing process of the pressing mechanism into the motor shaft mating hole 51.

[0043] Furthermore, as an alternative, the bottom wall 21 and the cavity wall 22 can also be arranged into a U-shaped structure, a hemispherical structure, or an inverted cone structure, etc., and the inverted cone structure can further limit the displacement of the RPS magnet 3 in the magnet receiving cavity 20 along the axial direction of the shaft 2.

[0044] The RPS magnet assembly of this utility model embodiment includes an integrally formed shaft 2 and a magnet receiving cavity 20. The magnet receiving cavity 20 is used to house the RPS magnet 3. During the process of pressing the shaft 2 into the motor shaft mating hole 51 using the pressing mechanism, the pressure acting on the magnet receiving cavity 20 is directly transmitted to the shaft 2, thereby making the downward pressure on the shaft 2 more vertical. Furthermore, the RPS magnet 3 is set in the magnet receiving cavity 20, which overcomes the problem of RPS magnet 3 being crushed due to the expansion and deformation of the shaft 2 after being pressed in the prior art. It also simplifies the assembly process and improves the stability of the product.

[0045] This utility model embodiment also provides an RPS magnet assembly pressing mechanism, which is used to press the RPS magnet assembly of any of the above embodiments into the motor shaft mating hole 51, such as... Figure 8 As shown, the pressing mechanism includes a pressing head 1, which engages with the side of the magnet receiving cavity 20 away from the shaft 2. The pressing head 1 has a clearance groove 11 for avoiding the RPS magnet 3. In this embodiment, the pressing mechanism is used to press the shaft 2 into the motor shaft mating hole 51. Specifically, the pressing head presses the shaft into the motor shaft mating hole 51 by applying pressure to the top of the side wall of the magnet receiving cavity 20. The clearance groove 11 on the pressing head 1 can prevent the pressing head 1 from damaging the RPS magnet 3.

[0046] This utility model embodiment also provides a motor, which adopts the RPS magnet assembly of any of the above embodiments.

[0047] Specifically, such as Figure 9 As shown, the motor in this embodiment includes a motor body 6, a motor shaft 5 connected to the motor body 6, and an RPS magnet assembly of any of the above embodiments. The motor shaft 5 is provided with a motor shaft mating hole 51, which is tightly mated with the shaft 2 of the RPS magnet assembly.

[0048] The RPS magnet assembly of this utility model embodiment includes an integrally formed shaft 2 and a magnet receiving cavity 20. The magnet receiving cavity 20 is used to house the RPS magnet 3. During the process of pressing the shaft 2 into the motor shaft mating hole 51 using the pressing mechanism, the pressure acting on the magnet receiving cavity 20 is directly transmitted to the shaft 2, thereby making the downward pressure on the shaft 2 more vertical. Furthermore, since the RPS magnet 3 is located in the magnet receiving cavity 20, it overcomes the problem of the RPS magnet 3 being crushed due to the expansion and deformation of the shaft after being pressed in the prior art. This reduces the scrap rate caused by the RPS magnet 3 being crushed during motor assembly.

[0049] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application shall have the ordinary meaning as understood by one of ordinary skill in the art to which this utility model pertains.

[0050] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model, and they should all be covered within the scope of the claims and specification of this utility model. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This utility model is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An RPS magnet assembly, characterized in that, It includes a shaft (2) with one end for tightly fitting with a motor shaft mating hole (51), and a magnet receiving cavity (20) is provided at the other end of the shaft (2). The magnet receiving cavity (20) is integrally formed with the shaft (2), and an RPS magnet (3) that rotates with the shaft (2) is provided in the magnet receiving cavity (20).

2. The RPS magnet assembly according to claim 1, characterized in that, The inner wall of the magnet receiving cavity (20) is provided with an annular groove (221). When the RPS magnet (3) is filled into the magnet receiving cavity (20) by injection molding, a flange is formed that cooperates with the annular groove (221) to limit the RPS magnet (3) along the axial direction of the shaft (2).

3. The RPS magnet assembly according to claim 1, characterized in that, At least one anti-rotation groove (223) is provided on the inner side wall of the magnet receiving cavity (20). When the RPS magnet (3) is filled into the magnet receiving cavity (20) by injection molding, a mating block is formed that cooperates with the anti-rotation groove (223) so that the RPS magnet (3) rotates with the shaft (2).

4. The RPS magnet assembly according to claim 1, characterized in that, The bottom wall of the magnet receiving cavity (20) is provided with at least one anti-rotation groove. When the RPS magnet (3) is filled into the magnet receiving cavity (20) by injection molding, a mating block is formed that cooperates with the anti-rotation groove so that the RPS magnet (3) rotates with the shaft (2).

5. The RPS magnet assembly according to claim 1, characterized in that, At least one positioning notch (222) is provided on the outer wall of the magnet receiving cavity (20), and the axis of the positioning notch (222) is parallel to the axis of the shaft (2).

6. The RPS magnet assembly according to claim 5, characterized in that, There are three positioning notches (222). Of the three positioning notches (222), one corresponds to the N pole of the RPS magnet (3), another corresponds to the S pole of the RPS magnet (3), and the third is located on the perpendicular line connecting the N pole and the S pole of the RPS magnet (3).

7. The RPS magnet assembly according to claim 1, characterized in that, The magnet receiving cavity (20) includes a cavity wall (22) and a bottom wall (21). One side of the bottom wall (21) is connected to the shaft (2). The cavity wall (22) is connected around the bottom wall (21). The cavity wall (22) extends away from the shaft (2) along the axis of the shaft (2).

8. The RPS magnet assembly according to claim 7, characterized in that, The cavity wall (22) and the bottom wall (21) form a tapered structure with the bottom wall (21) as the smaller end, and the radius of the bottom wall (21) is greater than the radius of the shaft (2).

9. An RPS magnet assembly pressing mechanism, characterized in that, The pressing mechanism is used to press the RPS magnet assembly according to any one of claims 1-8 into the motor shaft mating hole (51). The pressing mechanism includes a pressing head (1), which mates with the side of the magnet receiving cavity (20) away from the shaft (2). The pressing head (1) is provided with a clearance groove (11) for avoiding the RPS magnet (3).

10. An electric motor, characterized in that, The motor uses the RPS magnet assembly as described in any one of claims 1-8.

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