Disc type permanent magnet motor and rotor assembly thereof

Abstract

The rotor assembly of the disc type permanent magnet motor comprises a retainer, permanent magnets and magnetic conductive blocks, the retainer is provided with a magnet mounting surface, the permanent magnets are mounted on the magnet mounting surface, the permanent magnets are sequentially arranged on the magnet mounting surface along the circumferential direction, the magnetic conductive blocks are mounted on the magnet mounting surface, and the magnetic conductive blocks are mounted on the magnet mounting surface. Every two adjacent permanent magnets are spaced through a magnetic conductive block in the circumferential direction. The first end face of the magnetic conductive block protrudes out of the second end face of the permanent magnet on the side, away from the air gap, of the permanent magnet and the magnetic conductive block. According to the rotor assembly provided by the invention, the manufacturing cost of the disc type permanent magnet motor is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, in particular to a disc-type permanent magnet motor and a rotor assembly thereof. Background Art

[0002] Traditional disc-type permanent magnet motors use permanent magnets to generate permanent magnet torque. These motors consist of a stator assembly and a rotor assembly. The rotor assembly is equipped with permanent magnets, while the stator assembly is equipped with coil windings. When energized, these magnets mutually excite each other, generating torque.

[0003] However, since permanent magnets are expensive, the cost of generating torque using only permanent magnets at the same torque is high.

[0004] Therefore, how to reduce the manufacturing cost of disc permanent magnet motors is a technical problem that needs to be solved urgently by those skilled in the art. Utility Model Content

[0005] The purpose of the utility model is to provide a disc type permanent magnet motor and a rotor assembly thereof, so as to reduce the manufacturing cost of the disc type permanent magnet motor.

[0006] The rotor assembly of the disc-type permanent magnet motor provided in this application includes:

[0007] A retainer, wherein the retainer is provided with a magnet mounting surface;

[0008] A permanent magnet, wherein the permanent magnet is mounted on the magnet mounting surface, and a plurality of the permanent magnets are sequentially arranged along the circumferential direction on the magnet mounting surface;

[0009] A magnetic conductive block is installed on the magnet mounting surface, and along the circumferential direction, two adjacent permanent magnets are separated by the magnetic conductive block; on the side of the permanent magnet and the magnetic conductive block away from the air gap, the first end face of the magnetic conductive block protrudes outward from the second end face of the permanent magnet.

[0010] Optionally, in a rotor assembly of a disc-type permanent magnet motor, a height difference between the first end face of the magnetic conductive block and the second end face of the permanent magnet is 1 to 3 times the first air gap formed by the stator core and the magnetic conductive block.

[0011] Optionally, in a rotor assembly of a disc-type permanent magnet motor, the permanent magnet includes:

[0012] Permanent magnet body;

[0013] Pole shoes, two pole shoes are provided, and the two pole shoes are respectively located on opposite sides of the permanent magnet body along the axis of the rotor assembly.

[0014] Optionally, in a rotor assembly of a disc-type permanent magnet motor, the magnetic conductive block includes:

[0015] Magnetic body;

[0016] The outer ring magnetic conductive part is installed at the end of the magnetic conductive body away from the center along the radial direction of the motor, and the outer ring magnetic conductive part is made of soft magnetic composite material.

[0017] Optionally, in a rotor assembly of a disc-type permanent magnet motor, the magnetic conductive body is composed of silicon steel sheets stacked along the radial direction of the motor.

[0018] Optionally, in a rotor assembly of a disc-type permanent magnet motor, the retaining frame is provided with a first mounting groove for inserting the permanent magnet, the first mounting groove is connected one-to-one with the permanent magnet, and one of the two opposite side walls of the first mounting groove and the two opposite sides of the permanent magnet is provided with a first clamping groove, and the other is provided with a first protrusion that is clamped to the first clamping groove.

[0019] Optionally, in a rotor assembly of a disc permanent magnet motor, the retaining frame is provided with a second mounting groove for inserting the magnetic conductive block, the second mounting groove is connected one-to-one with the magnetic conductive block, and one of the two opposite side walls of the second mounting groove and the two opposite sides of the magnetic conductive block is provided with a second clamping groove, and the other is provided with a second protrusion that is clamped to the second clamping groove.

[0020] Optionally, in a rotor assembly of a disc-type permanent magnet motor, a retaining ring is further included, which is annular and is arranged on the outer periphery of all the permanent magnets and the magnetic blocks installed on the magnet mounting surface to limit the radial movement of the permanent magnets and the magnetic blocks.

[0021] Optionally, in a rotor assembly of a disc-type permanent magnet motor, the retaining ring is an annular ring, and the permanent magnet and the magnetic conductive block are both in contact with the inner surface of the retaining ring.

[0022] A disc-type permanent magnet motor comprises a rotor assembly and a stator assembly, wherein the rotor assembly is any one of the above-mentioned rotor assemblies.

[0023] In the above technical solution, the rotor assembly of the disc-type permanent magnet motor provided by the utility model includes a retaining frame, a permanent magnet and a magnetic conductive block. The retaining frame is provided with a magnet mounting surface, the permanent magnet is mounted on the magnet mounting surface, the magnet mounting surface is provided with multiple permanent magnets along the circumferential direction, the magnetic conductive block is mounted on the magnet mounting surface, and along the circumferential direction, two adjacent permanent magnets are separated by the magnetic conductive block; on the side of the permanent magnet and the magnetic conductive block away from the air gap, the first end face of the magnetic conductive block protrudes outward from the second end face of the permanent magnet.

[0024] As can be seen from the above description, in the rotor assembly of the disc-type permanent magnet motor provided by this application, two adjacent permanent magnets are separated by a magnetic block, and the permanent magnets and magnetic blocks are arranged alternately, fully utilizing the asymmetry of the magnetic circuit to generate reluctance torque. On the side of the permanent magnet and the magnetic block facing away from the air gap, the first end face of the magnetic block protrudes outward from the second end face of the permanent magnet, forming a stepped air gap between the permanent magnet and the magnetic block, thereby increasing the reluctance torque. This reduces the number of permanent magnets required while maintaining the same torque. Therefore, the rotor assembly provided by this application reduces the manufacturing cost of the disc-type permanent magnet motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0026] Figure 1 A schematic structural diagram of a disc-type permanent magnet motor provided by an embodiment of the present utility model;

[0027] Figure 2 A schematic structural diagram of a rotor assembly provided in an embodiment of the present utility model;

[0028] Figure 3 A schematic structural diagram of another rotor assembly provided by an embodiment of the present utility model;

[0029] Figure 4 A schematic structural diagram of a permanent magnet provided in an embodiment of the present utility model;

[0030] Figure 5 A schematic structural diagram of a magnetic conductive block provided in an embodiment of the present utility model;

[0031] Figure 6 A schematic structural diagram of a magnetic conductive body provided in an embodiment of the present utility model;

[0032] Figure 7 A schematic structural diagram of the outer ring magnetic conductive portion provided in an embodiment of the present utility model;

[0033] Figure 8 A schematic structural diagram of a magnetic conductive block provided in an embodiment of the present utility model;

[0034] Figure 9 This is a schematic diagram of the air gap position of the disc-type permanent magnet motor provided by an embodiment of the utility model.

[0035] in Figure 1-9 middle:

[0036] 1-rotor assembly, 11-retaining ring, 12-permanent magnet, 121-permanent magnet body, 122-pole shoe, 123-first slot, 13-magnetic block, 131-magnetic body, 132-outer ring magnetic portion, 133-second slot, 14-cage, 141-magnet mounting surface;

[0037] 2- stator coil;

[0038] 3- Stator core. DETAILED DESCRIPTION

[0039] The core of the utility model is to provide a disc-type permanent magnet motor and a rotor assembly thereof, so as to reduce the manufacturing cost of the disc-type permanent magnet motor.

[0040] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and implementation methods.

[0041] For ease of understanding, some terms are defined below:

[0042] Magnetoresistance effect: Magnetic lines of force always close along the path of minimum magnetic resistance, also known as salient polarity.

[0043] Magnetic block: Made of magnetic material, it has high magnetic permeability and low magnetic resistance.

[0044] Permanent magnet: Made of permanent magnetic materials, such as rare earth permanent magnets, ferrites, etc. It generates a permanent magnetic field with a magnetic permeability close to that of air, low permeability, and large magnetic resistance.

[0045] d-axis: the central axis of the permanent magnet.

[0046] q-axis: The symmetry line between two adjacent d-axes, which is 90 electrical degrees away from the d-axis.

[0047] Reluctance torque: Qualitatively, it's the torque generated by the reluctance effect. Quantitatively, it's (Ld - Lq) * id * iq, where Ld is the d-axis inductance, Lq is the q-axis inductance, id is the d-axis current, and iq is the q-axis current. Therefore, the greater the difference between the d- and q-axis inductances, the greater the reluctance torque.

[0048] Salient pole ratio: A measure of the magnitude of the magnetoresistance effect, specifically expressed as Lq / Ld.

[0049] Air gap: The gap between the stator assembly and the rotor assembly. This application uses a stepped air gap, where the stator core and the magnetic block form a first air gap a1, and the stator core and the permanent magnet form a second air gap a2.

[0050] Please refer to Figures 1 to 9 .

[0051] In one specific embodiment, the rotor assembly of a disc-type permanent magnet motor provided by the present invention includes a retainer 14, permanent magnets 12, and magnetic blocks 13. The retainer 14 is provided with a magnet mounting surface 141. The retainer 14 is used to mount the permanent magnets 12 and magnetic blocks 13. The retainer 14 can be made of non-magnetic materials such as aluminum alloy, stainless steel, composite materials, carbon fiber, etc. Specifically, the permanent magnets 12 can be made of a magnetic steel structure.

[0052] Specifically, as the area approaches the center of the circle, the areas formed by the permanent magnet 12 and the magnetic conductive block 13 in the circumferential direction gradually decrease.

[0053] The permanent magnet 12 is mounted on the magnet mounting surface 141. A plurality of permanent magnets 12 are mounted on the magnet mounting surface 141 along the circumferential direction. The magnetic conductive block 13 is mounted on the magnet mounting surface 141. Along the circumferential direction, two adjacent permanent magnets 12 are separated by the magnetic conductive block 13. Specifically, the permanent magnets 12 of adjacent magnetic conductive blocks 13 are spaced apart, that is, a gap is provided between the two. The permanent magnet 12 and the magnetic conductive block 13 are away from the side of the air gap, and the first end face of the magnetic conductive block 13 is convex to the second end face of the permanent magnet 12. In a specific embodiment, the permanent magnet 12 and the magnetic conductive block 13 are located in the same plane on the side close to the air gap, or the permanent magnet 12 and the magnetic conductive block 13 are not located in the same plane on the side close to the air gap.

[0054] Specifically, the height difference between the first end face of the magnetic block 13 and the second end face of the permanent magnet 12 is 1 to 3 times the first air gap a1. The height difference between the first end face of the magnetic block 13 and the second end face of the permanent magnet 12 forms a stepped air gap. Specifically, the height difference between the first end face of the magnetic block 13 and the second end face of the permanent magnet 12 is 2 times the air gap.

[0055] Of course, according to actual conditions, the height difference between the first end face of the magnetic block 13 and the second end face of the permanent magnet 12 and the multiple of the first air gap a1 are not limited to the above situation. Specifically, it is possible that the height difference between the first end face of the magnetic block 13 and the second end face of the permanent magnet 12 is greater than 3 times the first air gap a1.

[0056] Specifically, the rotor assembly 1 adopts a configuration in which permanent magnets 12 and magnetic blocks 13 are arranged alternately. The permanent magnets 12 and magnetic blocks 13 arranged on the rotor are respectively arranged symmetrically along the radial direction. That is, the permanent magnets 12 and magnetic blocks 13 are symmetrically distributed along the center line of the rotor assembly 1. Since the permanent magnets 12 of a certain thickness are placed on the d-axis, the magnetic resistance is very large, while the magnetic blocks 13 are placed on the q-axis, the magnetic resistance is very small. Therefore, the rotor assembly 1 has a large difference in inductance between the d-axis and the q-axis, making full use of the asymmetry of the inductance of the d-axis and the q-axis to generate reluctance torque. At the same time, the presence of the permanent magnets 12 will also interact with the stator assembly to generate permanent magnetic torque. For torque density considerations, if the number of motor poles is p, the arc of the permanent magnets 12 is preferably (360 / p*0.5)°, and the arc of the magnetic blocks 13 is preferably (360 / p*0.4)°.

[0057] The permanent magnet 12 and the magnetic block 13 are away from the side of the air gap, and the first end face of the magnetic block 13 protrudes from the second end face of the permanent magnet 12. That is, if the air gap side is taken as the bottom end, the height of the magnetic block 13 is higher than the height of the permanent magnet 12, so the air gap forms a stepped shape, and the air gap at the magnetic block 13 is small, and the air gap at the permanent magnet 12 is large, which further increases the difference between the d-axis and q-axis inductances, increases the asymmetry of the d-axis and q-axis inductances, and thus increases the reluctance torque. The stepped air gap is used to increase the motor salient pole ratio, increase the proportion of the motor reluctance torque, and improve the high-speed performance of the motor. The large difference between the d-axis and q-axis inductances makes full use of the asymmetry of the d-axis and q-axis inductances to generate reluctance torque, which can reduce the amount of permanent magnet 12 while meeting the same torque. Therefore, the rotor assembly 1 provided in this application reduces the manufacturing cost of the disc permanent magnet motor.

[0058] Since the assembly processing precision of the permanent magnet 12 is not high, this structure is adopted to improve the flatness of the permanent magnet 12 and reduce the scratching of the permanent magnet 12 .

[0059] like Figure 1 、 Figure 3 and Figure 4 As shown, the permanent magnet 12 includes a permanent magnet body 121 and a pole shoe 122. In this case, the permanent magnet 12 body can be a magnetic steel structure. Two pole shoes 122 are provided, and the two pole shoes 122 are respectively located on opposite sides of the permanent magnet body 121. Specifically, the two pole shoes 122 are distributed along the axis of the rotor assembly. By adding the pole shoes 122, the stator assembly leakage is reduced, and the salient pole ratio of the disc permanent magnet motor can be further improved, that is, the proportion of magnetic resistance torque is increased. At the same time, the pole shoes 122 can protect the permanent magnet 12 and avoid demagnetization. At the same time, a layer of pole shoes 122 can be covered on the permanent magnet 12 to make the air gap of the entire disc permanent magnet motor uniform.

[0060] The pole shoe 122 is made of magnetic conductive material, such as silicon steel sheet, steel, SMC, etc.

[0061] During specific assembly, the pole shoe 122 and the permanent magnet body 121 can be fixed by bonding, or the pole shoe 122 and the permanent magnet body 121 can be snapped together. For example, the pole shoe 122 and the permanent magnet body 121 are fixed by using a dovetail groove-shaped guide rail and a slider.

[0062] The magnetic conductive block 13 can be made of magnetic conductive materials, such as silicon steel sheets, steel, SMC (soft magnetic composite material) amorphous alloy, etc.

[0063] In a specific embodiment, Figures 5 to 8 As shown, the magnetic conductive block 13 includes a magnetic conductive body 131 and an outer ring magnetic conductive portion 132. Along the radial direction of the motor, the outer ring magnetic conductive portion 132 is installed at the end of the magnetic conductive body 131 away from the center of the circle. The outer ring magnetic conductive portion 132 is a soft magnetic composite material.

[0064] The mating surface between the magnetic conductive body 131 and the outer ring magnetic conductive portion 132 may be a plane, and the surface of the outer ring magnetic conductive portion 132 away from the magnetic conductive body 131 may be an arc-shaped surface.

[0065] like Figure 5 As shown, in a specific embodiment, the magnetic body 131 is composed of silicon steel sheets stacked along the radial direction of the motor. Since silicon steel sheets are relatively low in price, the magnetic body 131 is processed using silicon steel sheets, which simplifies the process and reduces the manufacturing cost of the rotor assembly 1. Since SMC is relatively expensive and silicon steel sheets (or other sheet-shaped magnetic conductive materials) cannot be processed into the arc at the top of the magnetic block 13 (away from the center of the circle), a composite structure of soft magnetic composite materials and silicon steel sheets is adopted for the magnetic block 13. The lower part (near the center of the circle) is formed by stacking silicon steel sheets to form the magnetic body 131, and the stacking direction is along the radial direction of the motor. The upper part is made of powder metallurgy of soft magnetic composite materials to form the outer ring magnetic portion 132.

[0066] In a specific embodiment, the retaining frame 14 is provided with a first mounting groove for inserting the permanent magnet 12. The first mounting groove is connected to the permanent magnet 12 in a one-to-one manner. One of the two opposite side walls of the first mounting groove and the opposite sides of the permanent magnet 12 is provided with a first engaging groove 123, and the other is provided with a first protrusion that is engaged with the first engaging groove 123. To facilitate the insertion of the permanent magnet 12, preferably, the first engaging groove 123 and the first protrusion are both straight bar structures. Specifically, the first protrusion can be provided on the side wall of the first mounting groove, and the side wall of the first mounting groove is the wall surface adjacent to the bottom wall of the first mounting groove. When the permanent magnet 12 is inserted into place in the retaining frame 14, the first protrusion is exactly engaged with the first engaging groove 123.

[0067] In a specific embodiment, the retaining frame 14 is provided with a second mounting groove for inserting the magnetic block 13, and the second mounting groove is connected to the magnetic block 13 one-to-one. The two opposite side walls of the second mounting groove and the opposite sides of the magnetic block 13 are provided with a second card groove 133 on one side, and the other is provided with a second protrusion that is engaged with the second card groove 133. In order to facilitate the insertion of the magnetic block 13, preferably, the second card groove 133 and the second protrusion are both straight bar structures. Specifically, the second protrusion can be provided on the side wall of the second mounting groove, and the side wall of the second mounting groove is a wall surface adjacent to the bottom wall of the second mounting groove. When the magnetic block 13 is inserted into place in the retaining frame 14, the second protrusion is just engaged with the second card groove 133.

[0068] In a specific embodiment, the rotor assembly 1 of the disc-type permanent magnet motor further includes a retaining ring 11, which is annular and is sleeved on the outer periphery of all permanent magnets 12 and magnetic blocks 13 mounted on the magnet mounting surface 141 to limit the radial movement of the permanent magnets 12 and magnetic blocks 13. Specifically, the retaining ring 11 can be fixedly connected to the retaining frame 14, and specifically, the two can be detachably connected. The present application achieves axial fixation of the permanent magnets 12 and the magnetic blocks 13 through the first protrusion and the second protrusion, and uses the retaining ring 11 to limit the radial displacement of the permanent magnets 12 and the magnetic blocks 13, thereby improving the installation stability of the permanent magnets 12 and the magnetic blocks 13.

[0069] The retaining ring 11 can be made of non-magnetic materials such as aluminum alloy, stainless steel, composite materials, carbon fiber, etc.

[0070] The retaining ring 11 is an annular ring, specifically, the retaining ring 11 can be a circular ring structure. The permanent magnet 12 and the magnetic block 13 are both in contact with the inner surface of the retaining ring 11, so as to facilitate the later disassembly and assembly of the permanent magnet 12 and the magnetic block 13.

[0071] like Figure 1 and Figure 2 As shown, the present application provides a disc-type permanent magnet motor, comprising a rotor assembly and a stator assembly, wherein the rotor assembly is any one of the above-mentioned rotor assemblies 1 .

[0072] The stator assembly includes a stator coil 2 and a stator core 3. The stator assembly can adopt a conventional stator assembly structure, which will not be described in detail in this question.

[0073] In one embodiment, the disc-type permanent magnet motor may include two stator assemblies and one rotor assembly 1 . In this case, along the axis of the rotor assembly, the two stator assemblies are located on opposite sides of the rotor assembly 1 .

[0074] In one embodiment, the disc-type permanent magnet motor may include a stator assembly and a rotor assembly 1 . In this case, the stator assembly and the rotor assembly 1 are arranged in sequence along the axis of the rotor assembly.

[0075] In one embodiment, the disc-type permanent magnet motor may include a stator assembly and two rotor assemblies 1 . In this case, along the axis of the rotor assembly, the two rotor assemblies 1 are located on opposite sides of the stator assembly.

[0076] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0077] The above description of the disclosed embodiments will enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A rotor assembly of a disc-type permanent magnet motor, characterized in that: include: A retaining frame (14), wherein the retaining frame (14) is provided with a magnet mounting surface (141); A permanent magnet (12), the permanent magnet (12) being mounted on the magnet mounting surface (141), wherein a plurality of the permanent magnets (12) are sequentially arranged along the circumferential direction on the magnet mounting surface (141); A magnetic conductive block (13) is installed on the magnet installation surface (141), and along the circumferential direction, two adjacent permanent magnets (12) are separated by the magnetic conductive block (13); on the side of the permanent magnet (12) and the magnetic conductive block (13) away from the air gap, the first end surface of the magnetic conductive block (13) protrudes outward from the second end surface of the permanent magnet (12).

2. The rotor assembly of the disc-type permanent magnet motor according to claim 1, characterized in that: The height difference between the first end face of the magnetic conductive block (13) and the second end face of the permanent magnet (12) is 1 to 3 times the first air gap formed by the stator core (3) and the magnetic conductive block (13).

3. The rotor assembly of the disc-type permanent magnet motor according to claim 1, characterized in that: The permanent magnet (12) comprises: Permanent magnet body (121); Pole shoes (122), two pole shoes (122) are provided, and the two pole shoes (122) are respectively located on opposite sides of the permanent magnet body (121) along the axis direction of the rotor assembly.

4. The rotor assembly of the disc-type permanent magnet motor according to claim 1, characterized in that: The magnetic conductive block (13) comprises: Magnetic body (131); An outer ring magnetic conductive portion (132) is installed along the radial direction of the motor at an end of the magnetic conductive body (131) away from the center of the circle. The outer ring magnetic conductive portion (132) is made of a soft magnetic composite material.

5. The rotor assembly of the disc-type permanent magnet motor according to claim 4, characterized in that: The magnetic conductive body (131) is composed of silicon steel sheets stacked along the radial direction of the motor.

6. The rotor assembly of the disc-type permanent magnet motor according to claim 1, characterized in that: The retaining frame (14) is provided with a first mounting groove for inserting the permanent magnet (12), the first mounting groove is connected to the permanent magnet (12) one-to-one, and two opposite side walls of the first mounting groove and two opposite sides of the permanent magnet (12) are provided with a first clamping groove (123) on one side, and a first protrusion clamped in the first clamping groove (123) on the other side.

7. The rotor assembly of the disc-type permanent magnet motor according to claim 1, characterized in that: The retaining frame (14) is provided with a second mounting slot for inserting the magnetic conductive block (13), the second mounting slot is connected to the magnetic conductive block (13) one-to-one, and one of the two opposite side walls of the second mounting slot and the two opposite sides of the magnetic conductive block (13) is provided with a second clamping slot (133), and the other is provided with a second protrusion clamped in the second clamping slot (133).

8. The rotor assembly of a disc-type permanent magnet motor according to any one of claims 1 to 7, characterized in that: The invention also includes a retaining ring (11), which is annular and is arranged on the outer periphery of all the permanent magnets (12) and the magnetic conductive blocks (13) installed on the magnet mounting surface (141) to limit the radial movement of the permanent magnets (12) and the magnetic conductive blocks (13).

9. The rotor assembly of the disc-type permanent magnet motor according to claim 8, characterized in that: The retaining ring (11) is an annular ring, and the permanent magnet (12) and the magnetic conductive block (13) are both in contact with the inner surface of the retaining ring (11).

10. A disc-type permanent magnet motor, comprising a rotor assembly and a stator assembly, characterized in that: The rotor assembly is the rotor assembly according to any one of claims 1 to 9.

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