Motor

Abstract

The utility model relates to a motor. The motor comprises a shell, a stator, a rotor, a motor shaft and a position sensor assembly, the stator is fixed in the shell, the rotor is rotatably installed on the radial inner side of the stator, the motor shaft is fixed on the radial inner side of the rotor and penetrates through the rotor in the axial direction, and the motor shaft comprises a first end and a second end which are opposite in the axial direction; the position sensor assembly includes a magnet secured to a first end and an angle sensor secured to a housing, the first end axially facing the angle sensor, the housing including an end cap axially separating the first end from the angle sensor. The motor further comprises a retaining seat, the motor shaft, the retaining seat and the magnet are respectively formed into an axially penetrating hollow structure, the retaining seat is fixed on the radial inner side of the first end, and the magnet is fixed on the radial inner side of the retaining seat, so that working fluid in the motor shaft can flow out of the first end along the axial direction through the retaining seat and the magnet. The motor provided by the utility model has an improved structure.

Description

Technical Field

[0001] This utility model relates to the field of motor technology. Specifically, this utility model relates to a motor with a position sensor. Background Technology

[0002] Currently, an increasing number of mechanical devices are using electric motors as drives. For example, in a vehicle's fully active suspension (Movement De-Activation, MDA), an electric motor is used to control the suspension. To ensure proper motor operation, position sensors need to be installed within the motor to detect the rotor's rotational position in real time. Position sensors used to detect the rotor's rotational position typically consist of two parts: an angle sensor (e.g., a Hall effect sensor) and a magnet. The magnet is fixedly mounted on the motor shaft and rotates synchronously with the rotor; the magnetic field it generates changes with the rotor's rotational position. The angle sensor is stationary relative to the stator and arranged opposite the magnet; it detects the changing magnetic field generated by the magnet.

[0003] In devices such as fully active suspensions, there is circulating oil in the motor. This oil flows in from one end of the hollow motor shaft and flows out from the other end, entering the motor's interior. The magnet for the position sensor is typically located at the oil outlet end. The magnet is mounted to the radially inner side of the motor shaft via a retainer. To install the retainer, multiple stepped surfaces are required at the end of the motor shaft bore, and the retainer is threaded into the bore. Furthermore, since the magnet blocks the outlet end of the bore, a T-hole is needed in the retainer to guide the oil radially out of the motor shaft. This makes the structure of the bore and retainer complex, difficult to manufacture, and costly to produce. Additionally, the solid magnet is susceptible to compression during installation and may be damaged by direct impact from the axially flowing oil during use. Utility Model Content

[0004] Therefore, the technical problem that this utility model needs to solve is to provide a motor that can improve the installation method of the position sensor.

[0005] The aforementioned technical problem is solved by an electric motor according to the present invention. The motor includes a housing, a stator, a rotor, a motor shaft, and a position sensor assembly. The stator is fixed in the housing, and the rotor is rotatably mounted radially inside the stator. The motor shaft is fixed radially inside the rotor and passes through the rotor axially. The motor shaft includes a first end and a second end opposite each other axially. The position sensor assembly includes a magnet fixed to the first end and an angle sensor fixed to the housing. The first end faces the angle sensor axially. The housing includes an end cap that axially separates the first end from the angle sensor. The motor also includes a retainer. The motor shaft, retainer, and magnet are each formed as a hollow structure extending axially. The retainer is fixed radially inside the first end, and the magnet is fixed radially inside the retainer, allowing the working fluid in the motor shaft to flow axially out of the first end via the retainer and the magnet. Because the magnet is formed as a hollow structure, the working fluid can flow directly axially through the magnet and thus out of the motor shaft from the first end. In this case, it is unnecessary to design complex flow channels in the retainer to guide the working fluid, thereby simplifying the structure of the retainer and the motor shaft. At the same time, it can reduce the axial impact force of the fluid on the magnet.

[0006] According to a preferred embodiment of the present invention, the end of the retainer facing the end cap can be formed as an open end that does not obstruct the magnet, and the end of the retainer facing away from the end cap can be formed with an end wall that axially abuts the magnet. The end wall may include a first through hole extending axially, and the magnet may include a second through hole extending axially, with the first through hole and the second through hole aligned. The end wall defines the axial position of the magnet relative to the retainer and can shield the magnet, reducing the fluid that directly impacts the magnet.

[0007] According to another preferred embodiment of the present invention, the inner diameter of the first through hole at the end abutting the magnet can be less than or equal to the inner diameter of the second through hole, so that the end wall completely blocks the magnet. This prevents the axially flowing fluid from directly impacting the magnet, thereby reducing the risk of damaging the magnet.

[0008] According to another preferred embodiment of the present invention, the inner diameter of the first through hole can gradually decrease axially toward the end cap. The first through hole thus forms a tapered hole with a diameter narrowing along the flow direction, thereby reducing the impact on the end wall.

[0009] According to another preferred embodiment of the present invention, the inner diameters of the first through hole and the second through hole can be smaller than the inner diameter of the motor shaft. This ensures that the magnet can have sufficient radial dimensions to generate a sufficient magnetic field.

[0010] According to another preferred embodiment of the present invention, the end of the magnet facing the end cap may protrude axially beyond the ends of the retainer and motor shaft facing the end cap. This allows the magnet to be closer to the angle sensor than the retainer and motor shaft, thereby ensuring detection effectiveness.

[0011] According to another preferred embodiment of the present invention, the magnet can be clearance-fitted with the retainer and fixed to the radially inner side of the retainer by adhesive. This facilitates the installation of the magnet into the retainer, reduces the compressive force on the magnet, and thus reduces the risk of damage to the magnet.

[0012] According to another preferred embodiment of the present invention, the retainer can be fixed to the radially inner side of the motor shaft by an interference fit. This avoids the need for thread machining, thereby saving manufacturing costs.

[0013] According to another preferred embodiment of the present invention, the motor shaft may include a stepped surface formed radially inward and axially facing the end cover, and the retainer abuts against the stepped surface axially. The stepped surface defines the axial position of the retainer relative to the motor shaft.

[0014] According to another preferred embodiment of the present invention, one of the magnet and the holder may include a positioning protrusion, and the other includes a positioning recess, wherein the positioning protrusion is inserted radially into the positioning recess to define the circumferential position of the magnet relative to the holder. This facilitates circumferential positioning of the magnet. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings. In the drawings, the same reference numerals represent elements with the same function. Wherein:

[0016] Figure 1 A longitudinal sectional view of an electric motor according to an exemplary embodiment of the present invention is shown;

[0017] Figure 2 Show Figure 1 The image shows a partial enlarged view of the motor at the end cover; and

[0018] Figure 3 Show Figure 1 The image shows an exploded 3D view of the motor at the end cover. Detailed Implementation

[0019] The following describes specific embodiments of the motor according to the present invention with reference to the accompanying drawings. The detailed description and drawings below are provided to exemplify the principles of the present invention. The present invention is not limited to the described preferred embodiments, and the scope of protection of the present invention is defined by the claims.

[0020] According to an embodiment of the present invention, an electric motor for operation in an environment in the presence of a working fluid is provided, the electric motor having a position sensor assembly for detecting the rotational position of the rotor. Figures 1 to 3 An exemplary embodiment of the motor according to the present invention is shown.

[0021] Figure 1 A longitudinal sectional view of an electric motor according to an exemplary embodiment is shown. Figure 1 As shown, the motor includes a housing 10, a stator 20, a rotor 30, a motor shaft 40, a retainer 70, a controller 80, and a position sensor assembly. The housing 10 provides mounting space for the various components of the motor. The stator 20 is fixedly mounted in the housing 10. The stator 20 is formed as a generally hollow cylindrical structure, and the rotor 30 is coaxially mounted radially inside the stator 20 and is rotatable relative to the stator 20 about a common central axis. The motor shaft 40 is formed as an elongated cylindrical structure, coaxially fixed to the radially inside the rotor 30 and passing through the rotor 30 axially. The motor shaft 40 includes two axially opposite ends, namely a first end ( Figure 1 The right end of the middle) and the second end ( Figure 1 The two ends (the left end of the rotor 30) protrude axially from the rotor 30 and are rotatably supported on the housing 10 (e.g., by bearings), so that the rotor 30 and the motor shaft 40 can rotate synchronously about a common central axis relative to the housing 10 and the stator 20.

[0022] The housing 10 includes a housing body 11 and an end cap 12. The housing body 11 may be formed as a generally cylindrical component. A through-hole is formed at one axial end of the housing 11, and the first end of the motor shaft 40 extends axially into the through-hole and is supported on the inner wall of the through-hole by a bearing. The end cap 12 is fixedly mounted in the through-hole and axially opposite the end face of the first end, thereby closing the through-hole. A controller 80 is fixed relative to the housing 10 and located on the side of the end cap 12 facing away from the motor shaft 40, such that the end cap 12 is axially positioned between the motor shaft 40 and the controller 80. The controller 80 may be, for example, an electronic device such as a printed circuit board. The position sensor assembly includes two separate components: a magnet 50 and an angle sensor 60. The magnet 50 is a magnetic component made of a material such as neodymium iron boron and is capable of generating a magnetic field. The magnet 50 is fixedly mounted on the first end of the motor shaft 40 by a retainer 70, thereby enabling it to rotate synchronously with the rotor 30 and the motor shaft 40. The retainer 70 is fixed to the radially inner side of the first end, and the magnet 50 is fixed to the radially inner side of the retainer 70. The retainer 70 can be made of a non-ferromagnetic material such as copper or aluminum. The angle sensor 60 is fixed to the housing 10 adjacent to the controller 80. The angle sensor 60 can be a sensing device such as a Hall sensor, which is connected to the controller 80 to transmit the detected angle signal to the controller 80. The angle sensor 60 can be directly fixed to the housing 10 (e.g., end cap 12), or it can be fixedly connected to the controller 80 and indirectly fixed to the housing 10 via the controller 80.

[0023] Figure 2 It shows Figure 1The image shows a partial enlarged view of the longitudinal section of the motor at end cover 12. (See image.) Figure 2 As shown, the first end of the motor shaft 40 faces the angle sensor 60 axially, and the end cap 12 axially separates the first end from the angle sensor 60 and the controller 80. The end cap 12 separates two different spaces. The motor according to this invention is used in environments where working fluids are present, such as the fully active suspension of a vehicle. In this application scenario, in Figure 2 On the left side of the middle end cover 12, that is, in the space of the housing 10 that accommodates the stator 20 and the rotor 30, there is a working fluid, which is usually engine oil. Figure 1 As shown, the motor shaft 40 is formed as a hollow structure extending axially through the shaft, with its second end extending axially outward from the other end of the housing 10, opposite to the end cover 12. Working fluid from outside the motor flows into the motor shaft 40 from the second end and flows along the hollow motor shaft 40 to the first end. Figure 2 As indicated by the arrow, the working fluid in the motor shaft 40 can flow out from the first end and enter the housing, that is, into the space where the stator 20 and rotor 30 are located, so that the working fluid can circulate in the motor.

[0024] As described in the background section, due to the obstruction of the magnet mounted at the first end, existing motor shafts require a complex structure at the first end to guide the working fluid out. The motor according to this invention improves the magnet mounting method. Specifically, in this motor, in addition to the motor shaft 40, the retaining seat 70 and the magnet 50 are also each formed as an axially penetrating hollow structure. The central cavities of the motor shaft 40, the retaining seat 70, and the magnet 50 are interconnected, allowing the working fluid in the motor shaft 40 to flow axially out of the first end through the central cavities of the retaining seat 70 and the magnet 50, thereby entering the housing 10.

[0025] As previously mentioned, the magnet 50 and the retainer 70 are typically made of different materials. Since the magnetic material used to manufacture the magnet 50 (e.g., neodymium iron boron) generally has low structural strength, it needs to be secured to the motor shaft 40 by means of the retainer 70. The material of the retainer 70 (e.g., copper or aluminum) can have relatively high strength. Preferably, to protect the magnet 50, the magnet 50 and the retainer 70 can be clearance-fitted, facilitating assembly. After the magnet 50 is installed in the retainer 70, it is then secured to the radially inner side of the retainer 70 using adhesive. Preferably, the retainer 70 can be directly secured to the radially inner side of the motor shaft 40 by an interference fit. Therefore, it is not necessary to machine threads on the motor shaft 40 and the retainer 70, thereby simplifying the manufacturing process.

[0026] Figure 3 An exploded perspective view of the motor at end cover 12 is shown. Figure 3As shown, in a specific embodiment, the retainer 70 can be formed as a generally cylindrical component. The end of the retainer 70 facing the end cap 12 is formed as an open end without an end wall, from which the magnet 50 can be axially inserted into the interior of the retainer. Viewed axially from the open end, the open end does not obstruct the magnet 50 installed in the retainer 70. At the end of the retainer 70 facing away from the end cap 12, i.e., the other end axially opposite to the open end, an end wall is formed extending radially inward from the side wall. On the one hand, viewed axially from this other end, the end wall partially obstructs the cavity inside the retainer 70; on the other hand, a first through hole 71 is formed at the center of the end wall, allowing working fluid from the motor shaft 40 to enter and pass axially through the retainer 70. When the magnet 50 is installed in the retainer 70, the magnet 50 abuts against the retainer 70 axially, thereby defining the axial position of the magnet 50 relative to the retainer 70. The magnet 50 can be formed as a generally hollow cylindrical component, i.e., a magnetic ring. A second through hole 51 is formed in the center of the magnet 50, extending axially. The first through hole 71 is aligned with the second through hole 51, so that the working fluid flowing into the retainer 70 through the first through hole 71 can flow through the magnet 50 and the retainer 70 through the second through hole 51, and finally flow out of the first end axially.

[0027] Since the first end is close to the end cap 12, the magnetic field generated by the magnet 50 can be detected by the angle sensor 60 located on the other side of the end cap 12. As the magnet 50 rotates with the rotor 30, the magnetic field also changes synchronously. The angle sensor 60 can detect the change in the magnetic field and thereby determine the rotational position of the rotor 30. Since the open end of the retainer 70 does not obstruct the magnet 50 at all, the angle sensor 60 can better detect the magnetic field generated by the magnet 50. Also, to facilitate the angle sensor 60's detection of the magnetic field, in a preferred embodiment, the end of the magnet 50 facing the end cap 12 can protrude axially beyond the ends of the retainer 70 and the motor shaft 40 facing the end cap 12, making the end face of the magnet 50 facing the angle sensor 60 closer to the angle sensor 60 than the end face of the first end of the motor shaft 40 and the end face of the retainer 70 facing the angle sensor 60. The end of the retainer 70 facing the end cap 12 can protrude beyond the first end, be flush with the first end, or be recessed into the first end; no limitation is made here.

[0028] The end wall of the retainer 70 faces the second end of the motor shaft 40, thus directly facing the direction of the incoming flow of the working fluid. The presence of the end wall can at least partially shield the magnet 50, thereby reducing the fluid impact force on the magnet 50. For this purpose, in a preferred embodiment, the inner diameter of the first through hole 71 at the end abutting the magnet 50 can be less than or equal to the inner diameter of the second through hole 51, so that the magnet 50 does not extend radially inward beyond the first through hole 71, and therefore, when viewed axially from the second end to the first end, the end wall of the retainer 70 completely shields the magnet 50. This prevents the flowing working fluid from directly impacting the magnet 50 axially. In this case, to reduce the fluid impact force on the retainer 70, the first through hole 71 can be formed as a generally conical hole. Figure 2 and Figure 3 As shown, the inner diameter of the first through hole 71 gradually decreases axially toward the end cap 12, thereby buffering the axial impact force of the working fluid. The central hole of the magnet 50 can be formed as a straight cylindrical hole, i.e., having an inner diameter that is approximately uniform along the axial direction. In this case, it is only necessary to make the inner diameter of the first through hole 71 at the end abutting the magnet 50 less than or equal to the inner diameter of the second through hole 51, while the inner diameter of the first through hole 71 in other axial regions can be greater than the inner diameter of the second through hole 51. As can be seen in the illustrated embodiment, although it is desirable to reduce the fluid impact force on the retainer 70 and the magnet 50, the inner diameters of the first through hole 71 and the second through hole 51 can still be smaller than the inner diameter of the motor shaft 40, so that the end wall of the retainer 70 and the magnet 50 can radially extend inward past the inner wall of the motor shaft 40. This is because the radial dimension of the motor shaft 40 is limited, and in order for the magnet 50 to generate the required magnetic field, it is necessary to ensure the radial width of the magnet 50 to increase its volume. In this case, the magnet 50 can still be protected by the end wall of the retainer 70.

[0029] In a preferred embodiment, such as Figure 2 As shown, a stepped surface 41 for positioning the retainer 70 can be formed on the radially inner side of the motor shaft 40. The stepped surface 41 is close to the first end of the motor shaft 40 and faces the end cover 12 axially. The retainer 70 abuts against the stepped surface 41 axially. The stepped surface 41 allows the retainer 70 to be positioned relative to the motor shaft 40 during assembly. The motor shaft 40 has different inner diameters on both sides of the stepped surface 41, with a smaller inner diameter on the side closer to the second end. In the aforementioned embodiment, the inner diameter of the motor shaft 40 compared to the first through hole 71 and the second through hole 51 specifically refers to the inner diameter on the side (narrower side) of the stepped surface 41 closer to the second end.

[0030] To determine the initial angle of rotation, the circumferential position of the magnet 50 relative to the motor shaft 40 needs to be defined. In a preferred embodiment, one of the magnet 50 and the retainer 70 may include one or more locating protrusions, while the other may include one or more corresponding locating recesses. When assembled in place, each locating protrusion is inserted radially into a corresponding locating recess, thereby defining the circumferential position of the magnet 50 relative to the retainer 70. For example, in Figure 2 In the illustrated embodiment, the magnet 50 has two radially protruding positioning protrusions 52 formed on its outer surface, while the retainer 70 has two radially recessed positioning recesses 72 formed on its inner surface. Each positioning protrusion 52 is radially inserted into a corresponding positioning recess 72. The positions of the positioning protrusions and positioning recesses can also be interchanged.

[0031] In the motor according to this invention, the magnet of the position sensor assembly is formed as a hollow structure, allowing the working fluid in the motor shaft to flow directly out of the motor shaft axially via the magnet. Therefore, it eliminates the need for a complex through-hole structure in the retainer to guide the working fluid. This simplifies the structure and assembly of the retainer and motor shaft, thereby reducing production costs. Simultaneously, the hollow magnet experiences less fluid impact, thus reducing the risk of magnet damage. Furthermore, the hollow magnet also saves on manufacturing materials.

[0032] While possible embodiments have been described exemplarily in the foregoing description, it should be understood that numerous variations of the embodiments exist through combinations of all known and readily conceived technical features and implementation methods. Furthermore, it should be understood that the exemplary embodiments are merely examples and do not in any way limit the scope, application, or construction of this invention. The foregoing description is more intended to provide those skilled in the art with technical guidance for transforming at least one exemplary embodiment, wherein various changes, particularly regarding the function and structure of the components, can be made without departing from the scope of the claims.

[0033] Appendix Label Table

[0034] 10. Shell

[0035] 11. Main body of the shell

[0036] 12 End Caps

[0037] 20 stators

[0038] 30 rotors

[0039] 40 motor shaft

[0040] 41 Stepped surface

[0041] 50 magnets

[0042] 51 Second through hole

[0043] 52 Positioning convex part

[0044] 60° angle sensor

[0045] 70. Maintain seat

[0046] 71 First through hole

[0047] 72 Positioning recess

[0048] 80 controller

Claims

1. An electric motor comprising a housing (10), a stator (20), a rotor (30), a motor shaft (40), and a position sensor assembly, wherein the stator (20) is fixed in the housing (10), the rotor (30) is rotatably mounted radially inside the stator (20), the motor shaft (40) is fixed radially inside the rotor (30) and passes through the rotor (30) axially, the motor shaft (40) includes a first end and a second end axially opposed to each other, the position sensor assembly includes a magnet (50) fixed to the first end and an angle sensor (60) fixed to the housing (10), the first end facing the angle sensor (60) axially, the housing (10) including an end cap (12) axially separating the first end from the angle sensor (60), characterized in that, The motor also includes a retainer (70). The motor shaft (40), the retainer (70) and the magnet (50) are each formed as an axially penetrating hollow structure. The retainer (70) is fixed to the radially inner side of the first end, and the magnet (50) is fixed to the radially inner side of the retainer (70), so that the working fluid in the motor shaft (40) can flow out of the first end axially through the retainer (70) and the magnet (50).

2. The motor according to claim 1, characterized in that, The end of the retainer (70) facing the end cap (12) is formed as an open end that does not obstruct the magnet (50). The end of the retainer (70) facing away from the end cap (12) has an end wall that abuts the magnet (50) axially. The end wall includes a first through hole (71) that extends axially. The magnet (50) includes a second through hole (51) that extends axially. The first through hole (71) and the second through hole (51) are aligned.

3. The motor according to claim 2, characterized in that, The inner diameter of the first through hole (71) at the end that abuts the magnet (50) is less than or equal to the inner diameter of the second through hole (51), so that the end wall completely blocks the magnet (50).

4. The motor according to claim 3, characterized in that, The inner diameter of the first through hole (71) gradually decreases axially toward the end cap (12).

5. The motor according to claim 4, characterized in that, The inner diameters of the first through hole (71) and the second through hole (51) are smaller than the inner diameter of the motor shaft (40).

6. The motor according to claim 2, characterized in that, The end of the magnet (50) facing the end cap (12) protrudes axially from the end of the retainer (70) and the end of the motor shaft (40) facing the end cap (12).

7. The motor according to claim 1, characterized in that, The magnet (50) is clearance-fitted with the retainer (70) and is fixed to the radially inner side of the retainer (70) by adhesive.

8. The motor according to claim 1, characterized in that, The retainer (70) is fixed to the radial inner side of the motor shaft (40) by an interference fit.

9. The motor according to claim 1, characterized in that, The motor shaft (40) includes a stepped surface (41) formed on the radially inner side and axially facing the end cap (12), and the retainer (70) abuts against the stepped surface (41) axially.

10. The motor according to any one of claims 1 to 9, characterized in that, One of the magnet (50) and the holder (70) includes a positioning protrusion (52) and the other includes a positioning recess (72), the positioning protrusion (52) being inserted radially into the positioning recess (72) to define the circumferential position of the magnet (50) relative to the holder (70).

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