Large-torque low-pulsation direct-drive brushless torque motor for unmanned electric steering wheel

Abstract

The invention discloses a large-torque low-pulse unmanned electric steering wheel direct-drive brushless torque motor, which comprises a stator and a rotor, the stator is provided with a mounting hole for the rotor to be mounted in, the peripheral side of the mounting hole is provided with 30 stator grooves which are arranged in an equal-indexing manner, the rotor comprises a cylindrical hollow shaft, and the hollow shaft is provided with an annular groove. A shaft sleeve is fixed on the outer side of the hollow shaft, 32 magnetic steels are fixed on the peripheral side of the shaft sleeve, and 30-slot 32-pole pole slot matching is formed between the 30 stator slots which are arranged in an equal indexing manner and the 32 magnetic steels; the magnetic steel is medium-grade magnetic steel; a winding is installed in a stator groove, the stator is further provided with a temperature measuring thermocouple for detecting the temperature of the winding, and the winding is in star connection. According to the method, torque pulsation optimization is carried out, it is ensured that stability and reliability can be achieved during large-torque operation, it is ensured that the steering wheel does not shake during steering, and multiple optimization is carried out, so that all indexes of the motor are more suitable for the using working condition and environment of the unmanned steering wheel.

Description

Technical Field

[0001] The present invention relates to the technical field related to electric power steering motors, and specifically to a direct-drive brushless torque motor for a large-torque and low-ripple driverless electric power steering wheel. Background Art

[0002] As a future development trend, driverless steering wheels have a wide range of applications. For example, they can be used on agricultural machinery or other transportation vehicles, and can accurately perform operations through a control system without manual intervention, reducing production costs and improving production efficiency; they can reduce work intensity, protect physical health, and avoid fatigue and injuries caused by long-term manual operation of the steering wheel; they can promote industry transformation and make the industry develop towards intelligence and unmannedness, symbolizing the future trend of autonomous driving.

[0003] As the most core component of a driverless steering wheel, the structure and performance indicators of the motor affect the overall design of the steering wheel; however, there are many deficiencies in existing steering wheel motors and need to be optimized and improved. Summary of the Invention

[0004] To solve the defects existing in the prior art, the present invention provides a direct-drive brushless torque motor for a large-torque and low-ripple driverless electric power steering wheel.

[0005] To solve the above technical problems, the present invention provides the following technical solutions:

[0006] A direct-drive brushless torque motor for a large-torque and low-ripple driverless electric power steering wheel of the present invention includes a stator and a rotor. An installation hole for the rotor to be inserted is provided on the stator, and 30 equally divided stator slots are provided on the periphery of the installation hole. The rotor includes a cylindrical hollow shaft, a shaft sleeve is fixed on the outer side of the hollow shaft, 32 permanent magnets are fixed on the periphery of the shaft sleeve, and a pole-slot combination of 30 slots and 32 poles is formed between the 30 equally divided stator slots and the 32 permanent magnets; the permanent magnets are medium-grade permanent magnets; windings are installed in the stator slots, a temperature-measuring thermocouple for detecting the temperature of the windings is also provided on the stator, and the windings are connected in a star connection;

[0007] The shaft sleeve is provided with positioning grooves corresponding to the permanent magnets one by one, and the permanent magnets are fixed in the positioning grooves through an adhesive layer. The mating surfaces of the permanent magnets and the shaft sleeve are both provided with inwardly recessed glue storage grooves, and chamfered structures are provided at the edge corners of the permanent magnets.

[0008] As a preferred technical solution of the present invention, the shaft sleeve and the hollow shaft are fixed by cylindrical pins. There are two cylindrical pins and they are arranged at an interval of 180 degrees, and pin holes for installing the cylindrical pins are provided on both the shaft sleeve and the hollow shaft.

[0009] As a preferred technical solution of the present invention, the stator is formed by laminating a plurality of punching sheets, and punching holes are formed on the punching sheets during die stamping. Bolts are installed in the punching holes of the stator to fix it to the machine shell.

[0010] As a preferred technical solution of the present invention, the shaft sleeve is made of a magnetic conductive material.

[0011] As a preferred technical solution of the present invention, the winding is formed by parallel winding of multiple enameled wires.

[0012] As a preferred technical solution of the present invention, the hollow shaft adopts anodic oxidation treatment, and a dense alumina film layer is formed on the surface of the aluminum alloy.

[0013] As a preferred technical solution of the present invention, an electromagnetic shielding layer is provided outside the temperature-measuring thermocouple, a signal wire is connected to the temperature-measuring thermocouple, and an electromagnetic shielding sleeve that wraps the signal wire is provided outside the signal wire.

[0014] The beneficial effects of the present invention are:

[0015] For this large-torque and low-ripple brushless torque motor for direct drive of driverless electric steering wheels, the torque ripple is optimized during large-torque operation; the star connection method is adopted to reduce harmonics; a glue storage groove is designed to ensure firm bonding of the magnetic steel; a cylindrical pin is fixed to prevent the rotor from spinning; a temperature-measuring thermocouple is added to monitor the motor temperature; parallel winding of multiple wires is carried out to reduce the labor intensity for convenient manual wire insertion; a plug and a solder tab are welded for convenient connection of the lead wire; an isolation boss design is adopted for the shaft sleeve to ensure uniform indexing of the magnetic steel bonding, etc., so that all aspects of the motor are more suitable for the operating conditions and environment of the driverless steering wheel. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention, and do not constitute a limitation to the present invention.

[0017] In the drawings:

[0018] Figure 1 is a schematic structural diagram of a large-torque and low-ripple brushless torque motor for direct drive of driverless electric steering wheels of the present invention;

[0019] Figure 2 is a schematic structural diagram of the pin hole of a large-torque and low-ripple brushless torque motor for direct drive of driverless electric steering wheels of the present invention;

[0020] Figure 3 is a schematic structural diagram of the stator slot of a large-torque and low-ripple brushless torque motor for direct drive of driverless electric steering wheels of the present invention;

[0021] Figure 4 It is a schematic structural diagram of the positioning groove of a direct-drive brushless torque motor for a large-torque and low-ripple driverless electric steering wheel according to the present invention;

[0022] Figure 5 It is a schematic structural diagram of the glue storage groove of a direct-drive brushless torque motor for a large-torque and low-ripple driverless electric steering wheel according to the present invention;

[0023] Figure 6 It is a schematic structural diagram of the chassis of a direct-drive brushless torque motor for a large-torque and low-ripple driverless electric steering wheel according to the present invention;

[0024] Figure 7 It is a schematic diagram of the bending state of the bending plate of a direct-drive brushless torque motor for a large-torque and low-ripple driverless electric steering wheel according to the present invention;

[0025] Figure 8 It is a schematic structural diagram of the card slot of the bending plate of a direct-drive brushless torque motor for a large-torque and low-ripple driverless electric steering wheel according to the present invention.

[0026] In the figure: 1, stator; 2, rotor; 3, mounting hole; 4, stator slot; 5, hollow shaft; 6, shaft sleeve; 7, permanent magnet; 8, winding; 9, temperature-measuring thermocouple; 10, positioning groove; 11, adhesive layer; 12, glue storage groove; 13, cylindrical pin; 14, pin hole; 15, punching; 16, chassis; 18, side plate; 19, convex block; 20, card slot; 21, clamping part; 22, limiting groove; 24, bending plate; 25, bending opening. Specific embodiments

[0027] The following is a description of the preferred embodiments of the present invention with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0028] Example: As Figures 1-5As shown in the figure, a direct-drive brushless torque motor for a large-torque and low-ripple driverless electric steering wheel according to the present invention includes a stator 1 and a rotor 2. An installation hole 3 for the rotor 2 to be inserted is provided on the stator 1, and 30 equally-spaced stator slots 4 are provided on the periphery of the installation hole 3. The rotor 2 includes a cylindrical hollow shaft 5, a shaft sleeve 6 is fixed on the outer side of the hollow shaft 5, and 32 permanent magnets 7 are fixed on the periphery of the shaft sleeve 6. A pole-slot combination of 30 slots and 32 poles is formed between the 30 equally-spaced stator slots 4 and the 32 permanent magnets 7; the permanent magnet 7 is a medium-grade permanent magnet; a winding 8 is installed in the stator slot 4, and a temperature-measuring thermocouple 9 for detecting the temperature of the winding 8 is further provided on the stator 1. The winding is connected in a star connection; to ensure the smooth operation of the motor, the motor should have a lower torque ripple under large torque. The motor is preferably of a multi-pole and multi-slot structure. The more the number of poles and slots, the greater the help in reducing the torque ripple. Finally, a pole-slot combination of 30 slots and 32 poles is adopted; the magnetic density of the tooth part of the stator core should not be too high. Excessive saturation of the tooth magnetic density will increase the torque ripple. Therefore, a medium-grade permanent magnet is selected to adjust the magnetic density; and the slot opening, slot shoulder height and slot shoulder angle of the stator punching are optimized. The winding connection method is selected as the star connection. The star connection has no third and third multiple harmonics, avoiding the losses and torque ripple brought by the third and third multiple harmonics. The above measures all reduce the torque ripple of the motor. The torque output by the steering wheel motor during operation is different according to different working conditions. When operating at the peak torque, the heat generation is faster. To be able to monitor the temperature of the motor in real time, a temperature-measuring thermocouple is added. Since the winding generates heat the fastest, the temperature sensor is buried inside the motor winding, which can accurately detect the highest temperature of the motor. Among them, the temperature-measuring thermocouple 9 is installed through a shock-absorbing frame and is closely attached to the winding.

[0029] The shaft sleeve 6 is provided with positioning grooves 10 corresponding to the permanent magnets 7 one by one, and the permanent magnets 7 are fixed in the positioning grooves 10 through an adhesive layer 11. Concave glue storage grooves 12 are provided on the mating surfaces of the permanent magnets 7 and the shaft sleeve 6, and rounded corners are provided at the edges and corners of the permanent magnets 7. During the bonding process of the permanent magnet and the shaft sleeve, since the permanent magnet is adsorbed to the shaft sleeve, the adhesive will be squeezed out, resulting in less residual glue film and reduced bonding strength. To ensure firm bonding, a glue storage groove design is carried out on the mating surfaces of the permanent magnet and the shaft sleeve, avoiding the problem of glue being squeezed out. At the same time, in order to avoid the edges of the permanent magnets from being knocked, a rounded corner design is carried out.

[0030] Among them, the shaft sleeve 6 and the hollow shaft 5 are fixed through two cylindrical pins 13 which are arranged at an interval of 180 degrees. Pin holes 14 for installing the cylindrical pins 13 are provided on both the shaft sleeve 6 and the hollow shaft 5. To ensure that the shaft sleeve and the hollow shaft do not rotate circumferentially during high-torque operation, a high-strength adhesive is applied to their mating surfaces, and two pin holes are drilled at positions 180 degrees apart, and the cylindrical pins are inserted into them, ensuring the fixing strength in the circumferential direction, adapting to various high-torque operating environments, and improving the reliability of the motor operation.

[0031] Among them, the stator 1 is formed by laminating a plurality of punched sheets, and punching holes 15 are formed on the punched sheets during die stamping. Bolts are installed in the punching holes 15 of the stator 1 to fix it to the machine housing. The stator punched sheets are manufactured by die stamping. Installation holes are left on the stator punched sheets during design. After the punched sheets are laminated into an iron core, the stator iron core is fixed to the housing through the installation holes. The installation holes are formed by die stamping and lamination, eliminating the drilling process and being convenient for disassembly and assembly.

[0032] Among them, the bushing 6 is made of a magnetic conductive material, and the magnetic steel is adhered to the bushing. To ensure uniform adhesion distribution of the magnetic steel, the bushing adopts positioning grooves to evenly isolate the magnetic steel from each other, eliminating the need for tooling for circumferential positioning and simplifying the adhesion process. The bushing uses a magnetic conductive material for magnetic conduction.

[0033] Among them, the winding 8 is formed by parallel winding of multiple enameled wires. To ensure that the motor can output a large torque, manual wire insertion is adopted to increase the slot fill factor, reduce copper loss, and increase the electrical loading. However, using a single enameled wire for winding will result in a relatively thick wire diameter, which is not easy to bend, increasing the difficulty of wire insertion and making the operation intensity of the operator high. The present invention adopts parallel winding of multiple wires, reducing the wire diameter. The enameled wire is easy to bend, facilitating wire insertion and shaping.

[0034] Among them, the surfaces of the stator and the rotor are both subjected to electrophoretic treatment to form an anti-corrosion layer. Electrophoresis has strong coverage ability for complex shapes and small holes, protecting the iron core from corrosion, and having outstanding environmental protection, high coating efficiency, and good decorative effect.

[0035] Among them, the hollow shaft is subjected to anodic oxidation treatment, forming a dense aluminum oxide film layer on the surface of the aluminum alloy. It has excellent corrosion resistance, can provide better protection in humid, acidic, and alkaline environments, and extend the service life of the motor. The hardness of the oxide film is usually higher than that of the aluminum alloy itself, which can improve the wear resistance and impact resistance of the hollow shaft, and has a good decorative effect.

[0036] Among them, an electromagnetic shielding layer is provided outside the temperature-measuring thermocouple 9, and a signal wire is connected to the temperature-measuring thermocouple 9, and an electromagnetic shielding sleeve that wraps the signal wire is provided outside the signal wire.

[0037] Such as Figures 6-8As shown, the magnet steel 7 is installed on the bushing 6 via an anti-detachment bracket. The anti-detachment bracket includes a bottom frame 16 inserted into the positioning groove 10. The bottom frame 16 is provided with a hollow cavity. On both sides of the bottom frame 16, there are vertical side plates 18 upwards. On the inner side of the upper ends of the side plates 18, there are protruding bumps 19. On the side wall of the magnet steel 7, there are card slots 20 for the bumps 19 to be inserted into. The bottom frame 16 is provided with a bent plate 24. On the inner side of the bottom of the bent plate 24, there is a bent opening 25 bent outwards. When the bent plate 24 is pressed inwards, the bottom of the bent plate 24 bends and opens towards both sides to form a clamping portion 21. On the bottom side of the positioning groove 10, there is a limiting groove 22 for the opened clamping portion 21 to be inserted into. On the bushing 6, there is a receiving groove for receiving the bottom frame 16. After the magnet steel 7 is inserted into the positioning groove 10, the magnet steel 7 is in close contact with the bottom groove surface of the positioning groove 10. Between the magnet steel 7 and the positioning groove 10, there is an adhesive layer 11 filled. In this way, the magnet steel 7 is extruded and then further extruded to make the magnet steel 7 in close contact with the positioning groove 10 on the adhesive layer 11, thus realizing the preliminary positioning function of the magnet steel.

[0038] Before the magnet steel 7 is loaded into the positioning groove 10, the anti-detachment bracket is installed on the magnet steel 7, so that the magnet steel 7 is inserted into the clip formed by the two side plates 18, and the bump 19 is inserted into the card slot 20. Then the magnet steel 7 is loaded into the positioning groove 10. Then, the anti-detachment bracket is extruded into the positioning groove 10. Because there is a bent opening bent outwards on the inner side of the bottom of the bent plate, when the bent plate is pressed inwards, the bottom of the side plate 18 bends and opens towards both sides to form a clamping portion 21, and the clamping portion 21 expands towards both sides, thus playing a positioning role. And the side plate 18 is also inserted into the positioning groove 10, so that the side plate 18 has a clamping and positioning effect on the magnet steel 7. And under the cooperation of the bump 19 and the card slot 20, it plays an anti-detachment role between the anti-detachment bracket and the magnet steel 7. And under the cooperation of the clamping portion 21 and the limiting groove 22, it plays an anti-detachment role on the anti-detachment bracket. In this way, the overall anti-detachment effect is achieved, and no positioning bolts are used, so it has the characteristic of convenient installation.

[0039] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A direct-drive brushless torque motor for an unmanned electric steering wheel with large torque and low ripple, characterized in that: It includes a stator (1) and a rotor (2). An installation hole (3) for the rotor (2) to be inserted is provided on the stator (1), and 30 equally divided stator slots (4) are provided on the periphery of the installation hole (3). The rotor (2) includes a cylindrical hollow shaft (5). A shaft sleeve (6) is fixed on the outer side of the hollow shaft (5). 32 permanent magnets (7) are fixed on the periphery of the shaft sleeve (6). A pole-slot combination of 30 slots and 32 poles is formed between the 30 equally divided stator slots (4) and the 32 permanent magnets (7); the permanent magnets (7) are medium-grade permanent magnets; windings (8) are installed in the stator slots (4). A temperature-measuring thermocouple (9) for detecting the temperature of the windings (8) is also provided on the stator (1). The windings are connected in star connection; The shaft sleeve (6) is provided with positioning grooves (10) corresponding to the permanent magnets (7) one by one, and the permanent magnets (7) are fixed in the positioning grooves (10) through an adhesive layer (11). Storage glue grooves (12) recessed inward are provided on the mating surfaces of the permanent magnets (7) and the shaft sleeve (6), and rounded corners are provided at the edge corners of the permanent magnets (7).

2. The brushless torque motor with direct drive for a large-torque and low-ripple driverless electric steering wheel according to claim 1, wherein The shaft sleeve (6) and the hollow shaft (5) are fixed through cylindrical pins (13). There are two cylindrical pins (13) which are arranged at an interval of 180 degrees, and pin holes (14) for installing the cylindrical pins (13) are provided on both the shaft sleeve (6) and the hollow shaft (5).

3. A direct-drive brushless torque motor for a large-torque and low-ripple driverless electric steering wheel according to claim 1, wherein, The stator (1) is formed by stacking multiple punching sheets, and punching holes (15) are formed on the punching sheets during punching. Bolts are installed in the punching holes (15) of the stator (1) to fix it to the machine shell.

4. A large-torque and low-ripple brushless torque motor for direct drive of an unmanned electric steering wheel according to claim 1, characterized in that, The shaft sleeve (6) is made of a magnetic conductive material.

5. A large-torque and low-ripple brushless torque motor for direct drive of an unmanned electric steering wheel according to claim 2, characterized in that, The windings (8) are formed by parallel winding of multiple enameled wires.

6. A direct-drive brushless torque motor for a large-torque and low-ripple driverless electric steering wheel according to claim 1, characterized in that, The surfaces of the stator and the rotor are both subjected to electrophoretic treatment to form an anti-corrosion layer.

7. A direct-drive brushless torque motor for a large-torque and low-ripple driverless electric steering wheel according to claim 1, characterized in that, The hollow shaft is subjected to anodic oxidation treatment to form a dense aluminum oxide film layer on the surface of the aluminum alloy.

8. A large-torque and low-ripple brushless torque motor for direct drive of an unmanned electric steering wheel according to claim 1, wherein An electromagnetic shielding layer is provided outside the temperature-measuring thermocouple (9). A signal wire is connected to the temperature-measuring thermocouple (9), and an electromagnetic shielding sleeve wrapping the signal wire is provided on the periphery of the signal wire.

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