CN110581620A - Brush assembly, motor comprising same and electric power steering system - Google Patents

Abstract

The invention discloses an electric brush assembly, which comprises a base, an electric brush, a spring and a stop part, wherein the electric brush is fixed on the base in a sliding manner, the spring and the stop part are arranged on the base, the base comprises a base plate, a brush box positioned on one end surface of the base plate, and a limit part positioned on the radial outer side of the brush box, the electric brush and the spring are accommodated in the brush box, two ends of the spring respectively abut against the electric brush and the stop part, the stop part comprises an abutting part abutting against the spring, and a supporting part extending from the abutting part and positioned on the radial outer side of the abutting part, and the supporting part abuts against the limit part. The invention effectively reduces the assembly process of the electric brush assembly. The invention also discloses a motor containing the brush component and an electric power steering system.

Description

Brush assembly, motor comprising same and electric power steering system

Technical Field

The invention relates to the field of motors, in particular to a brush assembly suitable for a brush motor, a motor comprising the brush assembly and an electric power steering system comprising the motor.

Background

The existing brush assembly generally includes a base, a plurality of brush holders fixed on the base, a brush slidably connected in the brush holders, a stopper, and a spring having two ends abutting against the brush and the stopper, respectively, wherein the brush holders and the stopper are generally made of brass. The central position of the base is provided with a through hole for penetrating the commutator. The spring is pressed against the electric brush under the abutting of the stop piece, so that one side, away from the spring, of the electric brush is in contact with the commutator, and current is transmitted to the commutator. During assembly, the electric brush support needs to be fixed on the base, then the electric brush, the spring and the stop piece are assembled one by one in sequence, the spring and the stop piece need to be installed in the radial direction and the axial direction respectively, and the assembly process is complex.

Disclosure of Invention

In view of the above, the present invention aims to provide a brush assembly, a motor including the brush assembly, and an electric power steering system that can solve or reduce the above problems.

To this end, in one aspect, the present invention provides an electric brush assembly, including a base, an electric brush slidably fixed on the base, and a spring and a stop member mounted on the base, where the base includes a base plate, a brush box located on an end surface of the base plate, and a limit portion located on a radial outer side of the brush box, the brush box accommodates the electric brush and the spring, two ends of the spring respectively abut against the electric brush and the stop member, the stop member includes an abutting portion abutting against the spring, and a support portion extending from the abutting portion and located on a radial outer side of the abutting portion, and the support portion abuts against the limit portion.

Furthermore, the stop piece comprises two supporting parts which are symmetrically distributed on two circumferential sides of the abutting part.

Furthermore, the abutting portion of the stopper is substantially sheet-shaped, the supporting portions are bent, and each supporting portion comprises a connecting section connected with the circumferential side edge of the abutting portion and a supporting section extending from the connecting section to the radial outer side of the substrate.

Furthermore, the connecting section of the supporting part and the abutting part are positioned on the same plane, and the distance between the supporting sections of the supporting parts on the two circumferential sides of the abutting part is gradually increased in the direction away from the abutting part.

In some embodiments, the stop member is correspondingly configured with two limiting portions, and a gap is formed between the two limiting portions at an interval for the stop member to pass through in the radial direction.

Furthermore, the limiting part is substantially L-shaped and comprises a first section extending from the substrate and a second section extending from the first section, the two limiting parts corresponding to the stop piece are symmetrically arranged, and the spacing distance between the two second sections is greater than that between the two first sections.

In some embodiments, the position-limiting portion is provided with a notch communicated with the notch, the notch has a first sidewall for abutting against the supporting portion, and the first sidewall is located at a radial outer side of the supporting portion.

In some embodiments, the stopper is made of metal, and is formed by stamping and bending, and the thickness of the stopper is between 0.25mm and 0.6 mm.

In another aspect, the invention further provides an electric machine, which includes the brush assembly.

In still another aspect, the present invention further provides an electric power steering system, which includes the aforementioned motor.

When the brush assembly is assembled, the spring and the stop part can be assembled together along the radial direction of the base plate without installing the spring and the stop part from different directions, so that the assembly process of the brush assembly is effectively reduced.

Drawings

Fig. 1 is a perspective view of a motor according to an embodiment of the present invention.

Fig. 2 is an exploded view at an angle of the motor shown in fig. 1.

Fig. 3 is an exploded view from another angle of the motor shown in fig. 1.

Fig. 4 is a perspective view of a brush assembly of the motor shown in fig. 3, with parts omitted.

Figure 5 is an exploded view of the brush assembly shown in figure 4.

Fig. 6 is a partially exploded enlarged view of the brush assembly shown in fig. 4.

Fig. 7 is a block diagram schematically illustrating a structure in which the motor shown in fig. 1 is applied to an electric power steering system.

Detailed Description

The invention will be described in detail with reference to the accompanying drawings and specific embodiments, so that the technical scheme and the beneficial effects of the invention are more clear. It is to be understood that the drawings are provided for purposes of illustration and description only and are not intended as a definition of the limits of the invention, but are drawn to scale.

Referring to fig. 1 to 3, the motor 20 includes a stator 30 having an open end, a rotor 40 rotatable with respect to the stator 30, a brush assembly 50 for transmitting current to the rotor 40, and an end cap 60 fixedly coupled to the open end of the stator 30. The stator 30 includes a housing and a permanent magnet 31 fixed in the housing. The housing is in a shape of a hollow cylinder with an opening at one end, a containing cavity is formed at the center of the housing, and the permanent magnet 31 is attached to the inner wall of the housing. The rotor 40 includes a rotating shaft 43, a rotor core 41 and a commutator 42 fixed to the rotating shaft 43, and a winding (not shown) wound around the rotor core 41. The rotor 40 is partially received in the receiving cavity of the stator 30, and the rotating shaft 43 penetrates through and protrudes from the end cover 60.

The brush assembly 50 is disposed at an open end of the stator 30 and inside the end cap 60. The brush assembly 50 includes a base 70 and a plurality of brushes 80 slidably secured to the base 70. In this embodiment, the brush assembly 50 further includes a conductive terminal 90 fixedly connected to the base 70, and a lead 100 connected to the conductive terminal 90. Specifically, the base 70 is substantially annular, and a through hole 71 is formed at a central position thereof for the commutator 42 and the rotating shaft 43 to pass through. The plurality of brushes 80 are arranged along the circumferential direction of the base 70, and a radially inner side surface 81 of each brush 80 is in slidable contact with the commutator 42. The brush 80 is connected to a shunt 83 at an axial top end thereof, and the shunt 83 is connected to the conductive terminal 90. The conductive terminal 90 includes a circumferential section 91 circumferentially disposed within the base 70 and an axial section 92 axially protruding from the base 70 (the complete conductive terminal 90 is visible in fig. 5). The lead 100 has one end connected to the axial section 92 of the conductive terminal 90 and the other end extending through and protruding out of the end cap 60. When current is supplied to the lead 100, the lead 100 transfers current through the terminal 110 to the conductive terminal 90, the conductive terminal 90 transfers current through the shunt 83 to the brush 80, and finally, the brush 80 transfers current through its radially inner side 81 to the commutator 42 and thus to the windings of the rotor 40. In this embodiment, the brush assembly 50 is fixedly connected to the end cap 60. For example, screws 61 may be used to extend through the base 70 of the brush assembly 50 and attach to the axial end face 62 of the end cap 60. The end cap 60 may also be fixedly connected to the stator 30 using screws 63. Specifically, lugs 32 with threaded holes may be added outside the open end of the stator 30 and a mounting plate 64 with threaded holes may be added outside the end cap 60. During installation, the aligned threaded holes of the lugs 32 and the threaded holes of the mounting plate 64 are connected by screws 63.

The brush assembly 50 will be described in further detail with reference to fig. 4-6.

In this embodiment, the base 70 of the brush assembly 50 includes a substantially annular base plate 71, and a plurality of limiting portions 72 and a plurality of brush boxes 73 extending from an axial end surface of the base plate 71. The plurality of limiting portions 72 and the plurality of brush boxes 73 extend in the radial direction of the base plate 71. The stopper portions 72 are located radially outward of the respective brush boxes 73. The brush assembly 50 also includes a plurality of springs 120 and a plurality of stoppers 130 mounted on the base 70. In this embodiment, the number of the brush box 73, the spring 120, and the stopper 130 is four. Each brush box 73 is hollow and is used for correspondingly accommodating one brush 80 and one spring 120. The stopper 130 is located radially outside the brush box 73, and both ends of the spring 120 respectively abut against the brush 80 and the stopper 130.

In this embodiment, the brush box 73 is U-shaped, and includes first and second side walls 730, 731 arranged along the circumferential direction, and a top wall 732 connecting the first and second side walls 730, 731, so that an opening 733, 734 is formed on each of the radially inner and outer sides of the brush box 73. The radially inner side 81 of the brush 80 can contact the commutator 42 through the opening 733 on the radially inner side of the brush box 73. The brush 80 and the spring 120 are mounted in the brush box 73 through an opening 734 on the radially outer side of the brush box 73. Preferably, the top wall 732 of the brush box 73 is provided with a U-shaped opening 735 in communication with a radially outer opening 734 of the brush box 73 for passage of the shunt 83 at the top of the brush 80. In this embodiment, a certain gap is reserved between the brush 80 and the inner wall of the brush box 73 to ensure that the brush 80 can slide freely in the brush box 73.

The spring 120 is configured to be arranged in a radial direction of the base plate 71, and one end of the spring 120 abuts against the radially outer side surface 82 of the brush 80. The stopper 130 includes a top portion 140 for abutting against the other end of the spring 120, and a plurality of support portions 150 extending from the top portion 140 toward the radial outside of the base plate 71. The supporting portion 150 abuts against the limiting portion 72 of the base 70 to achieve positioning and fixing.

When assembling the brush assembly 50, after the brush 80 is assembled into the brush box 73, the spring 120 and the stopper 130 are assembled together to the brush box 73 along the radial direction of the base plate 71, so that the spring 120 abuts against the brush 80 and the stopper 130 abuts against the stopper portion 72 of the base 70, thereby ensuring the sliding contact between the brush 80 and the commutator 42. In other words, the present embodiment does not require the spring 120 and the stopper 130 to be installed from different directions, so that the assembly process of the brush assembly 50 is effectively reduced, and the spring 120 and the stopper 130 are assembled in the same direction to maintain good contact therebetween, thereby improving NVH (Noise, Vibration, Harshness) performance of the motor 20.

Preferably, the base 70 is integrally formed by over-molding (overmold). Specifically, the conductive terminal 90 of the brush assembly 50 is placed in a mold, and then plastic is injected into the mold to form the integrated base 70, and the circumferential section 91 of the conductive terminal 90 is embedded in the base 70 to fix the conductive terminal 90. Thus, the base plate 71 is integrally connected with the brush boxes 73 and the limiting parts 72, and compared with the prior art, the process of assembling the brush boxes 73 on the base plate 71 is omitted, so that the assembling process of the brush assembly 50 can be further reduced. In addition, the base 70 is integrally formed, so that the positional accuracy between each brush box 73 and the corresponding stopper portion 72 can be improved, and each spring 120 can provide a relatively uniform abutting force for the corresponding brush 80. Meanwhile, compared with the prior art that the brush box 73 is made of copper, the brush box 73 is made of plastic, so that the manufacturing cost of the electric brush assembly 50 can be effectively reduced.

The stopper 130 may be made of metal, preferably steel, and may also be made of phosphor copper, beryllium copper, etc., preferably by stamping and then bending. The thickness of the stopper 130, i.e. the thickness of the abutting portion 140 and the supporting portion 150, may be between 0.25mm and 0.6mm, preferably 0.4 mm. Compared with the prior art that the stop part is usually made of copper, the stop part 130 is made of steel with higher strength, the thickness can be thinner and the manufacturing cost is lower under the condition of achieving the same strength.

In this embodiment, the abutting portion 140 of the stopper 130 is substantially in the shape of a sheet, and has a left side 141 and a right side 142 oppositely arranged along the circumferential direction of the base plate 71, an inner side 143 and an outer side 144 oppositely arranged along the radial direction of the base plate 71, and an upper end 145 and a lower end 146 oppositely arranged along the axial direction of the base plate 71. Preferably, the plurality of supporting portions 150 are symmetrically distributed on the left and right sides 141, 142 of the abutting portion 140, and each of the stopping members 130 is correspondingly configured with two limiting portions 72, that is, one limiting portion 72 corresponds to the supporting portion 150 abutting against the left side 141 of the abutting portion, and the other limiting portion 72 corresponds to the supporting portion 150 abutting against the right side 142 of the abutting portion, so as to improve the abutting stability of the stopping member 130. In this embodiment, the number of the supporting portions 150 is four, and the two supporting portions 150 are respectively connected to the left and right sides 141, 142 of the abutting portion 140.

In this embodiment, the supporting portion 150 is bent and includes a connecting section 151 connected to the left side 141 or the right side 142 of the abutting portion 140, and a supporting section 152 extending from the connecting section 151 toward the radial outer side of the base plate 71. Preferably, the connecting section 151 of the supporting portion 150 and the abutting portion 140 are located on the same plane, and the supporting section 152 of the supporting portion 150 and the connecting section 151 are arranged at an obtuse angle. Preferably, the supporting sections 152 of the supporting portions 150 on both sides of the same stopper 130 extend from the abutting portion 140 in an expanding manner, that is, the distance between the supporting sections 152 on both sides of the abutting portion 140 gradually increases in a direction away from the abutting portion 140. The stop member 130 thus designed has a converging effect on the abutting force from the two limiting portions 72, so that the abutting stability of the abutting portion 140 of the stop member 130 against the spring 120 can be further improved.

Preferably, the base 70 further includes a gap 74 between the two limiting portions 72, and the gap 74 is adapted to allow the spring 120 and the stopper 130 to pass through. Therefore, when assembling the brush assembly 50, the spring 120 and the stopper 130 are only required to be pushed through the notch 74 together along the radial direction of the base plate 71 until the spring 120 abuts against the brush 80 in the brush box 73 and the stopper 130 abuts against the limiting portion 72, so that the assembling process is simpler and more convenient. After the assembly is completed, the inner side 143 of the abutting portion 140 abuts against the spring 120, and the outer side 144 of the abutting portion 140 faces the notch 74.

In this embodiment, the limiting portion 72 of the base 70 is a column, which is substantially L-shaped and includes a first section 720 and a second section 721 that extend from the end surface of the base plate 71 in the axial direction. The cross-sectional area of the first section 720 is greater than the cross-sectional area of the second section 721. The two position-limiting portions 72 corresponding to each stop member 130 are symmetrically arranged on two circumferential sides of the radial end of the brush box 73, and the distance between the second sections 721 of the two position-limiting portions 72 is greater than the distance between the first sections 720. Preferably, the facing surfaces of the two second sections 721 respectively include a notch 722 communicating with the notch 74, and an end of the supporting section 152 of the supporting portion 150 abuts against a first sidewall of the notch 722 located at the radial outer side, so as to improve the abutting stability of the limiting portion 72 against the supporting portion 150 in the radial direction. Preferably, a first sidewall of the notch 722 located at the radially outer side is planar, and is preferably perpendicular to the radial direction of the base plate 71. The second side wall of the radial inner side of the notch 722 may be an inclined surface, so that when the support portion 150 slides into the notch 722 from the radial outer side of the limiting portion 72, the support sections 152 of the support portion 150 on both sides are pressed toward each other, so as to smoothly enter the notch 722, when the end of the support section 152 enters the notch 722, because the notch 722 provides an escape space, the end of the support section 152 may be restored to deform and rebound outward, and the end of the support section 152 radially abuts against the first side wall of the radial outer side of the notch 722. It is understood that the position-limiting portion 72 may also be configured to abut against the supporting portion 150 by using other engaging structures, for example, a protrusion is formed on the position-limiting portion 72, so that the end of the supporting portion 150 abuts against the protrusion. Preferably, the rib 723 of the limiting portion 72 radially inward of the notch 722 may abut against the middle portion of the supporting section 152 of the supporting portion 150. In this way, the supporting section 152 of the supporting portion 150 can be supported in an auxiliary manner, so as to prevent the stopper 130 from deforming under force, thereby improving the stability of the stopper 130 against the spring 120.

Preferably, the width of the upper end 145 and/or the lower end 146 of the abutting portion 140 is larger than the width of the middle portion of the abutting portion 140. The upper end and the lower end of the radial outer side of the first and the second side walls 730, 731 of the brush box 73 are respectively provided with a limit block 736. Preferably, the limiting blocks 736 are symmetrically distributed on the left and right sides 141, 142 of the abutting portion 140. This can limit the abutting portion 140 in the circumferential direction. Certain small gaps can be reserved between the upper end 145 and the lower end 146 of the abutting part 140 and the limiting block 736 in the circumferential direction, so that the abutting part 140 can be pushed to the brush box 73 during assembly. In addition, the two supporting portions 150 on each of the left and right sides 141, 142 of the abutting portion 140 are located between the two limit blocks 736 on the same side of the brush box 73. This can limit the support part 150 in the axial direction. A certain gap may be reserved between the supporting portion 150 and the limiting block 736 to facilitate the installation of the stopper 130. Therefore, the stopper 736 can simultaneously define the position of the abutting portion 140 in the circumferential direction and the position of the supporting portion 150 in the axial direction, thereby further improving the stability of the stopper 130.

Fig. 7 is a block diagram schematically showing a configuration in which the motor 20 of the present embodiment is applied to an electric power steering system. The electric power steering system includes a steering column 10, the aforementioned motor 20, a sensor (not shown), and a controller (not shown). When the electric power steering system is operated, the sensor detects the magnitude and direction of the torque of the steering column 10 and transmits the signal to the controller, which controls the motor 20 through a relevant algorithm, thereby outputting an appropriate torque. Since the main improvement point of the present invention is that the motor 20 and the other components of the electric power steering system except the motor 20 can adopt conventional structures and principles, the detailed description of the other components will not be provided in this embodiment.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-listed embodiments, and any simple changes or equivalent substitutions of technical solutions that can be obviously obtained by those skilled in the art within the technical scope of the present invention are within the protection scope of the present invention.

Claims (10)

1. The utility model provides an electric brush subassembly, includes the base, be fixed in slidable brush on the base, and install in spring and stop part on the base, its characterized in that, the base includes a base plate, is located the brush box of a base plate terminal surface and is located the spacing portion in the radial outside of brush box, the brush is held in the brush box with the spring, the both ends of spring support respectively the brush with the stop part, the stop part include with the spring support the top portion of supporting, and from the top portion extends be located the supporting part in the radial outside of top portion, the supporting part with spacing portion butt.

2. The brush assembly according to claim 1, wherein the stopper includes two support portions symmetrically distributed on both circumferential sides of the abutting portion.

3. The brush assembly according to claim 2, wherein the abutting portion of the stopper is substantially plate-shaped, the supporting portions are bent, and each of the supporting portions includes a connecting section connected to a circumferential side edge of the abutting portion, and a supporting section extending from the connecting section toward a radially outer side of the base plate.

4. The brush assembly according to claim 3, wherein the connecting section of the supporting portion and the abutting portion are located on the same plane, and a distance between the supporting sections of the supporting portion on both circumferential sides of the abutting portion gradually increases in a direction away from the abutting portion.

5. The brush assembly according to claim 2, wherein the stopper is correspondingly configured with two limiting portions, and a gap is formed between the two limiting portions for the stopper to pass through in the radial direction.

6. The brush assembly according to claim 5, wherein the stopper portion has a substantially L-shape including a first section extending from the base plate and a second section extending from the first section, the first section and the second section being symmetrically disposed with respect to the two stopper portions of the stopper portion, and a spacing distance between the two second sections is greater than a spacing distance between the two first sections.

7. The brush assembly according to claim 5, wherein the retaining portion has a recess communicating with the gap, the recess having a first sidewall for abutting against the support portion, the first sidewall being located radially outward of the support portion.

8. The brush assembly of claim 1, wherein the stop is made of metal and is stamped and then bent, and the thickness of the stop is between 0.25mm and 0.6 mm.

9. An electric machine, characterized in that the electric machine comprises a brush assembly according to any one of claims 1-8.

10. An electric power steering system characterized by comprising the electric motor according to claim 9.