CN217159433U - Electric drive and electric brush thereof - Google Patents

Abstract

The application provides an electric driver and a brush. The end of the contact part of the brush is provided with a contact surface for sliding contact with a contact piece of the commutator, and the contact part is limited among the front side surface, the back side surface, the left side surface and the right side surface. The left side surface or the right side surface is a front guiding side, and the included angle between the front guiding side and the advancing direction is less than 10 degrees. The leading side and the leading side surface define a leading portion on a contact face, the contact portion having a first total length in the forward direction and a second total length in the left-right direction. The leading portion is longer in the left-right direction the farther from the contact surface front edge in the advancing direction. The length of the leading portion in the left-right direction is not more than 10% of the second total length at 5% times the first total length from the leading edge of the contact surface in the advancing direction. The brush has good performance and is easy to manufacture.

Description

Electric drive and electric brush thereof

Technical Field

The present application relates to devices for generating mechanical driving force from electrical energy conversion, and more particularly to direct current drives and brushes therefor.

Background

The motor generates noise when operating. For example, the wiper uses a brushed dc motor as a drive. The technician finds that the noise of the wiper motor may come from the brush commutator, but the noise is difficult to eliminate.

SUMMERY OF THE UTILITY MODEL

The motor noise-generating technical problem that exists among the prior art is mainly solved to this application.

To solve the above technical problems, the present application provides a brush for being mounted to a brush holder, capable of moving in an advancing direction relative to a commutator when the commutator rotates and electrically contacting conductive contact pieces around the commutator in a sliding manner,

the brush comprises a support part and a contact part distributed in the longitudinal direction,

an end portion of the contact portion has a contact surface for slidably contacting the contact piece, the contact portion is defined between a front side surface, a rear side surface, a left side surface and a right side surface, the front side surface and the rear side surface are opposite in the advancing direction, the left side surface and the right side surface are opposite in a left-right direction, the left-right direction is perpendicular to the advancing direction, the left side surface or the right side surface is a leading side, an angle between the leading side and the advancing direction is less than 10 degrees, the leading side and the front side surface define a leading portion on the contact surface, the contact portion has a first total length in the advancing direction and a second total length in the left-right direction, the leading portion has a greater length in the left-right direction the farther the leading edge of the contact surface in the advancing direction, and is 5% of the leading edge of the contact surface in the advancing direction, the first total length is greater, the length of the leading portion in the left-right direction is not more than 10% of the second total length.

In some specific embodiments, the supporting portion is defined between a front supporting surface, a rear supporting surface, a left supporting surface and a right supporting surface, the front supporting surface and the rear supporting surface are opposite in the advancing direction, the left supporting surface and the right supporting surface are opposite in the left and right direction, the distance between the front guiding portion and the contact surface is less than 5% of the total length of the second portion, the included angle between the left supporting surface and the advancing direction is less than 10 degrees, the distance between the front guiding portion and the contact surface is 10% times of the front edge of the first portion in the advancing direction, and the length of the front guiding portion in the left and right direction is not more than 20% of the total length of the second portion.

In some embodiments, the front side surface forms an angle of not more than 87 degrees and not less than 45 degrees with the leading side, and a length of the leading portion in the left-right direction is not more than 45% of the second total length at 20% of the front edge of the contact surface in the advancing direction.

In some embodiments, the leading side is parallel to or intersects with the left support surface, the leading side and the left support surface are both parallel to the advancing direction, and the left support surface is parallel to the right support surface.

In some embodiments, an intersection line of the left side surface and the contact surface is parallel to an intersection line of the right side surface and the contact surface, and the contact portion is inside the support portion in a projection on a plane perpendicular to the longitudinal direction.

In another aspect, the present application provides an electric drive comprising:

a housing;

a brush holder secured to the housing, the brush holder defining a longitudinally extending track;

the commutator can rotate around a main axis relative to the shell, a plurality of conductive contact pieces are arranged on the periphery of the commutator, and every two contact pieces are separated by an insulating gap in the circumferential direction of the commutator; and

in the above-mentioned brush, the support portion is mounted on the rail, the contact surface is in sliding electrical contact with the contact pieces of the commutator, the contact surface sequentially slides over the contact pieces in the circumferential direction when the commutator rotates around the main axis, and the leading portion is located at the insulation gap when the contact surface crosses over one insulation gap from a current one of the contact pieces to just contact a next one of the contact pieces.

In some embodiments, the main axis is perpendicular to the longitudinal direction or the angle between the main axis and the longitudinal direction is not less than 60 degrees and not more than 85 degrees, and the left-right direction is parallel to the main axis.

In some embodiments, the main axis is at an angle of not less than 70 degrees to the longitudinal direction, and the electric drive further comprises a spring that exerts a resilient force on the brush in a resilient preload manner towards the contact blade.

In some embodiments, the rail slidingly contacts the support portion to define the brush to be movable only in the longitudinal direction, and the contact portion is integrally formed with the support portion.

In some embodiments, the insulation gap is a slot having a width of less than 2 mm extending in a direction parallel to the major axis, the brush has a length less than a length of one of the contact pads in a circumferential direction of the commutator, and the insulation gap has a length of no more than 2 mm. In another aspect, the present application provides.

According to the solution of the present application, the brush has a special leading portion having a length in the left-right direction that is greater the farther away from the leading edge of the contact surface in the advancing direction, the length of the leading portion in the left-right direction being no greater than 10% of the second total length at 5% times the first total length from the leading edge of the contact surface in the advancing direction. Therefore, the brush contacts the next contact piece for a small part when moving from one contact piece to the next contact piece across the insulation gap of the commutator, and then gradually enlarges the contact, which is advantageous for reducing noise. Meanwhile, the front guide part is limited by partial side surface of the contact part, and the electric brush has reasonable structure, stable performance and good manufacturability. In some embodiments, the leading side is angled less than 10 degrees from the forward direction, the leading portion is less than 5% of the second total length away from the extreme edge of the contact surface in the left-right direction, and the leading portion does not require too much material to be removed for machining.

Drawings

Specific embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 shows a schematic view of an embodiment of an electric drive with an armature housing removed;

FIG. 2 shows a schematic view of one embodiment of a brush;

FIG. 3 shows a schematic view of the brush of FIG. 2 viewed in the longitudinal direction;

FIG. 4 shows a schematic view of one brush contacting commutator of one embodiment as viewed from the major axis direction, with the brush about to move from the current contact to the next contact;

fig. 5 shows a schematic view of the commutator of fig. 4 after a certain angle of rotation, in which the brush has contacted the next contact piece while also partially contacting the present contact piece;

figure 6 shows a schematic view of the brush in contact with the contact blades as viewed radially when the commutator is in the position shown in figure 4;

figure 7 shows a schematic view of the brush in contact with the contact blades as viewed radially when the commutator is in the position shown in figure 5;

fig. 8 shows a schematic view of a contact piece removed from the original contact of the brush as viewed in the radial direction moving to the next contact piece;

FIG. 9 is a schematic enlarged view of a portion A of FIG. 6;

FIG. 10 is an enlarged partial schematic view of another embodiment shown in the same position as in FIG. 9;

FIG. 11 shows a schematic view of another embodiment in the same position as shown in FIG. 6;

FIG. 12 shows a schematic view of an electric drive of one embodiment with the longitudinal direction of the brushes perpendicular to the main axis of the commutator; and

fig. 13 shows a schematic view of an electric drive according to an embodiment in which the longitudinal direction of the brushes makes an angle unequal to 90 degrees with the main axis of the commutator.

Detailed Description

Referring to fig. 1 to 9, in some embodiments, an electric drive includes a brush 1, a commutator 2, a brush holder 3, and a housing 4.

The housing 4 includes an armature housing (not shown) and a transmission housing 40. In the electric drive of one embodiment shown in fig. 1, the armature housing is removed and the several magnets that are typically fixed in the armature housing are also removed. A transmission (not shown, for example, a worm and worm gear transmission) is mounted in the transmission case 40.

A plurality of electrically conductive contact pieces 21 are provided on the outer periphery of the commutator 2. Every two contact plates 21 are separated by an insulation gap 22 in the circumferential direction of the commutator 2, so that the contact plates 21 are insulated from each other. The insulation gap 22 is, for example, a slot extending in a direction parallel to the main axis with a width of less than 2 mm. The length of the insulation gap 22 in the circumferential direction is not more than 2 mm, for example 0.5, 0.8, 1.2 or 1.5 mm. The commutator 2 is rotatable relative to the housing 4 about the main axis in a direction of rotation 83. For example, the commutator 2 is fixed to the rotor 20, and the rotor 20 is wound with a plurality of windings 28. The plurality of windings 28 are electrically connected to respective contact pieces 21 of the commutator 2. The windings 28 are located in the magnetic field of the magnets fixed to the armature housing, and the energized windings 28 are driven by the magnetic field to urge the rotor 20 to rotate continuously in the direction of rotation 83.

Three brush holders 3 are fixed to the housing 4. Each brush holder 3 defines a track 30 extending in a longitudinal direction 84. One brush 1 is mounted in each brush holder 3. The brush 1 is connected to the lead 14. The wire 14 is flexible, for example, the wire 14 is composed of a plurality of strands of fine copper wire. When the commutator 2 rotates in the rotation direction 83, the brush 1 attached to the brush holder 3 moves relative to the commutator 2 in the forward direction 81, and electrically contacts the conductive contact pieces 21 around the commutator 2 in a sliding manner. Thereby achieving variable application of direct current to the respective windings 28 connected to the respective contact pieces 21.

The brush 1 is integrally formed with graphite. In some embodiments, the length of the brush 1 is less than the length of one contact piece 21 in the circumferential direction of the commutator 2, and thus the length of the contact surface 100 of the brush 1 is less than the length of one contact piece 21. Thus, the brush 1 contacts two contact pieces 21 at the same time and does not contact three or more contact pieces at the same time at most.

The brush 1 includes a contact portion 10 and a support portion 12 distributed in the longitudinal direction. That is, the contact portion 10 and the support portion 12 are distributed at different longitudinal positions, and the contact portion 10 and the support portion 12 are respectively located at two different sections in the longitudinal direction 84. The contact portion 10 and the support portion 12 of the brush 1 are respectively square.

The support portion 12 is defined between a front support surface 121, a rear support surface 122, a left support surface 123 and a right support surface 124. The front support surface 121 and the rear support surface 122 are opposed in the forward direction 81, and the left support surface 123 and the right support surface 124 are opposed in the left-right direction 82. The contact portion 10 is defined between a front side 101, a rear side 102, a left side 103, and a right side 104. The front side 101, the back side 102, the left side 103 and the right side 104 are all planar. The front side surface 101 and the rear side surface 102 face each other in the forward direction 81, and the left side surface 103 and the right side surface 104 face each other in the left-right direction 82. The left-right direction 82 is perpendicular to the advancing direction 81. For example, the left-right direction 82 is parallel to the major axis. The front support surface 121, the rear support surface 122, the left support surface 123 and the right support surface 124 are all parallel to the longitudinal direction 84. The support 12 is mounted in a square rail 30. The periphery of the support portion 12 engages the inner wall of the track 30. The rail 30 slidingly contacts the support 12, and the inner walls of the rail 30 contact the front support surface 121, the rear support surface 122, the left support surface 123 and the right support surface 124, respectively, thereby limiting the brush 1 to move only in the longitudinal direction 84, not in a direction perpendicular to the longitudinal direction 84, and not in rotational movement.

The end of the contact portion 10 has a contact surface 100 for slidably contacting the contact piece 21. The contact surface 100 is in sliding electrical contact with the contact 21 of the commutator 2 to conduct electricity on the conductor 14 to the contact 21 through the brush 1.

The length of the contact portion 10 in a direction perpendicular to the longitudinal direction 84 is smaller than the length of the support portion 12, that is to say the contact portion 10 is located inside the support portion 12 in projection on a plane perpendicular to the longitudinal direction 84. As shown in fig. 6, the position of the support portion 12 is indicated by a broken line, the projection of the contact portion 10 overlaps the contact surface 100, and the contact surface 100 is located inside the support portion 12. This structure can be machined from a square graphite blank. In some embodiments, the contact surface 100 is substantially parallelogram-shaped.

In some embodiments, the left side 103 is the leading side. In other embodiments, the right side 104 is the leading side. The leading side and the front side surface 101 define a leading portion 106 on the contact surface 100. The angle between the leading side and the direction of advance 81 is less than 10 degrees. For example, the leading side is parallel to the advancing direction 81, or the leading side is at an angle of 2 degrees, 4 degrees, 6 degrees, 8 degrees, or 10 degrees to the advancing direction 81.

During rotation of the commutator 2 about the main axis, the contact surfaces 100 slide past the individual contact blades 21 in succession in the circumferential direction. The leading portion 106 is located at the insulation gap 22 when the contact face 100 crosses over one insulation gap 22 from the current one contact 21 to just contact the next contact 21, as shown in fig. 6, 9 and 10. The contact portion 10 has a first overall length D1 in the advancing direction 81 and a second overall length D2 in the left-right direction 82. The length d2 of the leading portion 106 in the left-right direction 82 increases the further the leading portion 106 is from the leading edge of the contact surface 100 in the forward direction 81. The distance D1 to the leading edge of the contact surface 100 in the advancing direction 81 is 5% times the first total length D1. The length D2 of the leading section 106 in the left-right direction 82 is no greater than 10% of the second overall length D2. For example, the length D2 of the leading portion 106 in the left-right direction 82 is 3%, 6%, or 8% of the second overall length D2. The distance D1 to the leading edge of the contact surface 100 in the advancing direction 81 is 10% times the first total length D1, and the length D2 of the leading portion 106 in the left-right direction 82 is not more than 20% of the second total length D2. For example, the length D2 of the leading portion 106 in the left-right direction 82 is 12%, 16%, or 18% of the second overall length D2. At 20% of the first total length D1 from the leading edge of the contact surface 100 in the advancing direction 81, the length D2 of the leading portion 106 in the left-right direction 82 is not more than 45% of the second total length D2. For example, the length D2 of the leading portion 106 in the left-right direction 82 is 32%, 36%, or 38% of the second overall length D2.

In some embodiments, the electric drive further comprises a spring 5. The spring 5 is, for example, a pre-compressed helical spring or a torsion spring. The spring 5 is loaded at the longitudinal end 109 of the brush 1. The tail end 109 is located at the opposite end of the contact face 100. Therefore, the spring 5 exerts an elastic force on the brush 1 toward the contact piece 21 with elastic preload. The resilient force of the spring 5 holds the brush 1 against the commutator 2, and even if the brush 1 is worn and shortened, the spring 5 can push the brush 1 further.

The extreme edge of the leading portion 106 from the contact surface 100 in the left-right direction 82 is less than 5% of the second overall length D2. For example, the leading portion 106 abuts against the outermost edge of the contact surface 100, or the leading portion 106 is spaced from the outermost edge of the contact surface 100 by 1%, 2%, 3%, or 4% of the second total length D2. The angle between the left support surface 123 and the forward direction 81 is less than 10 degrees. For example, the left-hand support surface 123 is parallel to the advancing direction 81, or the left-hand support surface 123 forms an angle of 1 degree, 2 degrees, 3 degrees, 5 degrees, 6 degrees, 7 degrees, 8 degrees, or 9 degrees with the advancing direction 81.

In some embodiments, anterior facet 101 forms an angle with the leading side that is no greater than 87 degrees and no less than 45 degrees. For example, the anterior side 101 forms an angle of 48, 50, 55, 60, 65, 70, or 80 degrees with the anterior side. And the processing amount of the larger included angle is less, and the processing is easier. A smaller included angle facilitates a smaller leading portion 106 and easier noise reduction.

In some embodiments, the left support surface 123 is parallel to the advancing direction 81, and the leading side is parallel to or intersects the left support surface 123. The left side surface 103 and the right side surface 104 are both parallel to the advancing direction 81, or either one of them is parallel to the advancing direction 81. The left support surface 123 is parallel to the right support surface 124. The intersection of the left side 103 with the contact surface 100 is parallel to the intersection of the right side 104 with the contact surface 100.

In some embodiments shown in fig. 12, the major axis is perpendicular to the longitudinal direction 84. In some embodiments shown in fig. 13, the major axis is at an angle of not less than 60 degrees and not more than 85 degrees from the longitudinal direction 84. For example, the major axis may be at an angle of 70 degrees, 75 degrees, 80 degrees, or 83 degrees from the longitudinal direction 84.

Notwithstanding the foregoing, the scope of protection of the present application is defined by the claims. Other embodiments are possible according to the present application, for example, in some embodiments as shown in fig. 10, the front side 101 and the leading side (left side 103) may each be at least partially non-planar and may be radiused near the leading edge to form a rounded corner at the leading edge rather than a sharp corner. In some embodiments as shown in fig. 11, the front side 101 and the leading side (left side 103) may be processed into a plurality of planes. Wherein, the part of the front side surface 101 close to the front edge is a slightly concave arc surface, and the part of the front side surface 101 far away from the front edge is a plane which is basically parallel to the direction of the main axis; the portion of the left side surface 103 closer to the front edge presents a plane with a greater angle to the advancing direction 81, and the portion of the left side surface 103 farther from the front edge presents a plane substantially parallel to the advancing direction 81. Although brush 1 is shown as being configured with an axisymmetric shape for contact surface 100, those skilled in the art will appreciate that an asymmetric shape is also possible in other embodiments. The electric brush 1 with the symmetrical shape is beneficial to the condition that the reverse rotation is needed, and when the commutator 2 reverses, smaller noise can be obtained; on the other hand, the brush 1 having a symmetrical shape generates less noise not only when the leading edge of the contact surface 100 crosses the contact piece 21 but also when the trailing edge of the contact surface 100 leaves the contact piece 21. In yet another aspect, the contact surface 100 may be textured or not textured.

Description of the reference numerals

Electric brush 1

Contact part 10

Contact surface 100

Front side 101

Rear side 102

Left side surface 103

Right side surface 104

Leading portion 106

Tail end 109

Support part 12

Front support surface 121

Rear support surface 122

Left stay surface 123

Right brace face 124

Wire 14

Commutator 2

Rotor 20

Contact piece 21

Insulation gap 22

Winding 28

Brush holder 3

Track 30

Housing 4

Transmission housing 40

Spring 5

Advancing direction 81

Left and right direction 82

Direction of rotation 83

Longitudinal direction 84

Distance to leading edge d1

First total length D1

d1 front leader left-right length d2

A second overall length D2.

Claims (10)

1. -an electric brush, intended to be mounted on a brush holder (3), capable of moving in an advancing direction with respect to the commutator (2) when the commutator (2) rotates and of sliding electrical contact with a peripherally conductive contact piece (21) of the commutator (2), characterized in that,

the brush comprises a support part (12) and a contact part (10) distributed in the longitudinal direction,

the end of the contact portion (10) has a contact surface (100) for slidably contacting the contact piece (21), the contact portion (10) is defined between a front side surface (101), a rear side surface (102), a left side surface (103) and a right side surface (104), the front side surface (101) and the rear side surface (102) are opposite in the advancing direction, the left side surface (103) and the right side surface (104) are opposite in the left-right direction, the left-right direction is perpendicular to the advancing direction, the left side surface (103) or the right side surface (104) is a leading side, an angle between the leading side and the advancing direction is less than 10 degrees, the leading side and the front side surface (101) define a leading portion (106) on the contact surface (100), the contact portion (10) has a first total length in the advancing direction and a second total length in the left-right direction, the leading portion (106) has a length in the left-right direction of the leading portion (106) that is greater the farther away in the advancing direction from the leading edge of the contact surface (100), the length in the left-right direction of the leading portion (106) being not greater than 10% of the second total length at 5% of the leading edge of the contact surface (100) in the advancing direction.

2. The brush according to claim 1, wherein the support portion (12) is defined between a front support surface (121), a rear support surface (122), a left support surface (123) and a right support surface (124), the front support surface (121) and the rear support surface (122) are opposite in the forward direction, the left support surface (123) and the right support surface (124) are opposite in the left-right direction, the distance from the leading portion (106) to the edge of the contact surface (100) in the left-right direction is less than 5% of the second total length, the angle between the left support surface (123) and the forward direction is less than 10 degrees, the distance from the leading portion (100) in the forward direction is 10% of the first total length, and the length of the leading portion (106) in the left-right direction is not more than 20% of the second total length.

3. The brush of claim 1, wherein the front side (101), the rear side (102), the left side (103), and the right side (104) are each planar, the front side (101) forms an angle with the leading side of no more than 87 degrees and no less than 45 degrees, and the length of the leading portion (106) in the left-right direction is no more than 45% of the second total length at 20% of the leading edge of the contact surface (100) in the forward direction.

4. The brush according to claim 2, wherein the leading side is parallel to or intersects the left bearing surface (123), the leading side and the left bearing surface (123) are both parallel to the advancing direction, the left bearing surface (123) is parallel to the right bearing surface (124).

5. Brush according to claim 1, wherein the intersection of the left side (103) with the contact surface (100) is parallel to the intersection of the right side (104) with the contact surface (100), the contact portion (10) being inside the support portion (12) in a projection on a plane perpendicular to the longitudinal direction.

6. Electric drive, characterized in that it comprises:

a housing (4);

a brush holder (3) fixed to the housing (4), the brush holder (3) defining a rail (30) extending in a longitudinal direction;

the commutator (2) can rotate around a main axis relative to the shell (4), a plurality of conductive contact pieces (21) are arranged on the periphery of the commutator (2), and every two contact pieces (21) are separated by an insulating gap (22) in the circumferential direction of the commutator (2); and

the brush as claimed in any of claims 1 to 5, the support portion (12) being mounted to the track (30), the contact face (100) being in sliding electrical contact with contacts (21) of the commutator (2), the contact face (100) sliding over each of the contacts (21) in sequence in the circumferential direction as the commutator (2) rotates about the main axis, the leading portion (106) being located at a current one of the contacts (21) when the contact face (100) crosses over the one of the insulation gaps (22) from the current one of the contacts (21) to just contact a next one of the contacts (21).

7. The electric drive according to claim 6 wherein the main axis is perpendicular to the longitudinal direction or the main axis is at an angle of not less than 60 degrees and not more than 85 degrees to the longitudinal direction, the left-right direction being parallel to the main axis.

8. The electric drive according to claim 6, wherein the angle of the main axis with the longitudinal direction is not less than 70 degrees, the electric drive further comprising a spring (5), the spring (5) exerting an elastic force on the brush in an elastic preloading towards the contact blade (21).

9. Electric drive according to claim 6, wherein the rail (30) slidingly contacts the support (12) defining that the brush is movable only in the longitudinal direction, the contact portion (10) being integral with the support (12).

10. The electric drive according to claim 6, wherein the insulation gap (22) is a slot extending in a direction parallel to the main axis with a width of less than 2 mm, the length of the brush being less than the length of one of the contact blades (21) in the circumferential direction of the commutator (2), the length of the insulation gap (22) being not more than 2 mm.

Images