Brush holder assembly and electric device

Abstract

The present invention provides a brush holder assembly and an electric device, which relate to the technical field of electric devices, so as to optimize the structure of the brush holder assembly to a certain extent and reduce the problem of ablation caused by overload operation of the electric device. The brush holder assembly provided by the present invention includes a base plate, an insulating pad, a brush mechanism and a fuse; the insulating pad is made of a heat-expanding material and is arranged on the base plate, the brush mechanism is arranged on the insulating pad, the base plate is formed with an extension part, and the extension part is a conductive material; the brush mechanism includes a positive brush assembly and a negative brush assembly, one end of the positive brush assembly is electrically connected to the fuse, and the extension part corresponds to the contact part of the other end of the positive brush assembly and there is a gap between the two; when the insulating pad reaches a predetermined temperature, the insulating pad expands and drives the contact part of the positive brush assembly to touch the extension part, so that the fuse is melted.

Description

Technical Field

[0001] The present invention relates to the technical field of electric device equipment, and in particular to a brush holder assembly and an electric device. Background Art

[0002] An electric device is a device that converts electrical energy into mechanical energy through the principle of electromagnetic induction. At present, the overload protection of electric devices is to melt the fuse. This process requires the electric device to be short-circuited internally to generate a short-circuit current. Generally, the short circuit is achieved through the armature. In this way, when the current is low, the armature generates heat at a lower speed than the heat dissipation speed, so it is not easy to short-circuit, which can easily cause the problem of electric device ablation.

[0003] Therefore, there is an urgent need to provide a brush holder assembly and an electric device to solve the problems existing in the prior art to a certain extent. Summary of the invention

[0004] The object of the present invention is to provide a brush holder assembly and an electric device, so as to optimize the structure of the brush holder assembly to a certain extent and reduce the problem of ablation caused by overload operation of the electric device.

[0005] The present invention provides a brush holder assembly, comprising a base plate, an insulating pad, a brush mechanism and a fuse; the insulating pad is made of a heat-expanding material and is arranged on the base plate, the brush mechanism is arranged on the insulating pad, the base plate is formed with an extension portion, and the extension portion is a conductive material; the brush mechanism comprises a positive brush assembly and a negative brush assembly, one end of the positive brush assembly is electrically connected to the fuse, the extension portion corresponds to the contact portion of the other end of the positive brush assembly and there is a gap between the two; when the insulating pad reaches a predetermined temperature, the insulating pad expands and drives the contact portion of the positive brush assembly to touch the extension portion, so that the fuse is blown.

[0006] Wherein, the thermal expansion material of the insulating pad has a linear expansion coefficient of 1.0×10 -4 / K~1.4×10 -4 / K insulating material.

[0007] Specifically, the extension portion includes a connecting section, an inclined section and a contact section; one end of the connecting section is connected to the bottom plate, and the other end is connected to one end of the inclined section, the other end of the inclined section extends toward the bottom plate and is connected to one end of the contact section, and the contact section is located above the contact portion to form the gap.

[0008] Among them, the positive electrode brush assembly includes a first brush assembly and a second brush assembly, and the negative electrode brush assembly includes a third brush assembly and a fourth brush assembly; the extension portion formed on the bottom plate includes a first extension portion formed corresponding to the first brush assembly and a second extension portion formed corresponding to the second brush assembly; the insulating pad includes a first insulating pad and a second insulating pad symmetrically arranged, and the first insulating pad and the second insulating pad are both fan-shaped sheet structures; the first insulating pad and the second insulating pad are arranged opposite to each other, and the first brush assembly and the third brush assembly are arranged on the first insulating pad, and the second brush assembly and the fourth brush assembly are arranged on the second insulating pad.

[0009] Specifically, the first brush assembly and the third brush assembly located on the first insulating pad are symmetrically arranged with the second brush assembly and the fourth brush assembly located on the second insulating pad.

[0010] Further, the fuse includes a first connecting portion and a second connecting portion, a first wire is connected between the positive brush assembly and the fuse, and the number of the first wires corresponds to the number of the positive brush assemblies; the first connecting portion is connected to an end of the first brush assembly away from the first extension portion through the first wire, and the second connecting portion is connected to an end of the second brush assembly away from the second extension portion through the first wire.

[0011] Among them, the positive brush assembly and the negative brush assembly both include a positioning seat, an elastic member and a carbon brush; the positioning seat is connected to the insulating pad and the base plate, the elastic member is arranged in the positioning seat, one end of the carbon brush is connected to one end of the elastic member, and the other end protrudes from the positioning seat.

[0012] Specifically, a second wire is connected between the negative brush assembly and the base plate, and the number of the second wires corresponds to the number of the negative brush assemblies; one end of the first wire is connected to the carbon brush of the positive brush assembly, and the other end is connected to the fuse; one end of the second wire is connected to the carbon brush of the negative brush assembly, and the other end is connected to the base plate.

[0013] Furthermore, the brush holder assembly provided by the present invention further includes a bushing, wherein the bushing is connected to the base plate, one end of the fuse passes through the bushing to contact the first wire, and the other end passes through the bushing.

[0014] Compared with the prior art, the brush holder assembly provided by the present invention has the following advantages:

[0015] The brush holder assembly provided by the present invention comprises a base plate, an insulating pad, a brush mechanism and a fuse; the insulating pad is made of a heat-expanding material and is arranged on the base plate, the brush mechanism is arranged on the insulating pad, the base plate is formed with an extension portion, and the extension portion is a conductive material; the brush mechanism comprises a positive brush assembly and a negative brush assembly, one end of the positive brush assembly is electrically connected to the fuse, the extension portion corresponds to the contact portion of the other end of the positive brush assembly and there is a gap between the two; when the insulating pad reaches a predetermined temperature, the insulating pad expands and drives the contact portion of the positive brush assembly to touch the extension portion, so that the fuse is blown.

[0016] From this analysis, it can be known that the insulating pad and the brush mechanism can be stably installed through the bottom plate, and the energy conversion can be realized through the set positive brush assembly and negative brush assembly. Since one end of the positive brush assembly in the present application is connected to the fuse through the first wire, an extension portion made of conductive material is formed on the bottom plate and is spaced apart from the other end of the positive brush assembly, and the insulating pad in the present application is made of a heat-expanding material. Therefore, when an overload occurs, the temperature inside the electric device gradually increases, causing the insulating pad to expand due to the heat, thereby driving the positive brush assembly to move in a direction close to the extension portion until one end of the positive brush assembly contacts the extension portion.

[0017] Since the extension part is made of conductive material, when the contact part of the positive brush assembly contacts the extension part, an internal short circuit can be formed, so that the fuse is blown, thereby reducing the problem of ablation when the electric device is overloaded to a certain extent.

[0018] In addition, the present invention also provides an electric device including the brush holder assembly.

[0019] By adopting the electric device of the brush holder assembly provided in the present application, short-circuit protection can still be performed under low current conditions, thereby reducing the risk of ablation. In addition, the brush holder assembly provided in the present application can also control the internal short-circuit point during overload, thereby improving the safety of the overall device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A schematic structural diagram of a brush holder assembly provided by an embodiment of the present invention;

[0022] Figure 2A schematic structural diagram of a brush holder assembly from a first viewing angle provided by an embodiment of the present invention;

[0023] Figure 3 A structural schematic diagram of a brush holder assembly from a second viewing angle provided by an embodiment of the present invention;

[0024] Figure 4 for Figure 3 A partial enlarged view of point A in the middle.

[0025] In the figure: 1-bottom plate; 101-first extension; 1011-connecting section; 1012-inclined section; 1013-contact section; 102-second extension; 103-gap; 2-first insulating pad; 3-second insulating pad; 4-positive brush assembly; 401-first brush assembly; 402-second brush assembly; 5-negative brush assembly; 501-third brush assembly; 502-fourth brush assembly; 6-first wire; 7-second wire; 8-fuse; 801-first connecting part; 802-second connecting part; 9-positioning seat; 10-elastic member; 11-carbon brush; 12-bushing. DETAILED DESCRIPTION

[0026] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0027] In the description of the embodiments of the present application, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or are the positions or positional relationships in which the invented product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0028] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0029] In the description of the embodiments of the present application, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "setting", "installation", "connection", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

[0031] For ease of description, spatial relative terms such as "above", "upper", "below", and "lower" may be used herein to describe the relationship of one element to another element as shown in the drawings. Such spatial relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the drawings.

[0032] The terms used herein are only used to describe various examples and are not used to limit the present disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms "include", "comprise" and "have" list the stated features, quantities, operations, components, elements and / or their combinations that exist, but do not exclude the existence or addition of one or more other features, quantities, operations, components, elements and / or their combinations.

[0033] Variations in the shapes shown in the drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include variations in shapes that occur during manufacturing.

[0034] The features of the examples described herein may be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible as will be apparent after understanding the disclosure of the present application. In addition, the technical solutions between the various embodiments may be combined with each other, but must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be considered that the combination of such technical solutions does not exist and is not within the scope of protection required by the present application.

[0035] Figure 1 A schematic diagram of the overall structure of a brush holder assembly provided by an embodiment of the present invention; Figure 2 A schematic structural diagram of a brush holder assembly from a first viewing angle provided by an embodiment of the present invention; Figure 3 A structural schematic diagram of a brush holder assembly from a second viewing angle provided by an embodiment of the present invention; Figure 4 for Figure 3 A partial enlarged view of point A in the middle.

[0036] like Figure 1 Combination Figure 4 As shown, the present invention provides a brush holder assembly, including a base plate 1, an insulating pad, a brush mechanism and a fuse 8; the insulating pad is made of a heat-expanding material and is arranged on the base plate 1, the brush mechanism is arranged on the insulating pad, the base plate 1 is formed with an extension portion, and the extension portion is a conductive material; the brush mechanism includes a positive brush assembly 4 and a negative brush assembly 5, one end of the positive brush assembly 4 is connected to the fuse 8 through a first wire 6, the extension portion corresponds to the contact portion of the positive brush assembly 4 and a gap 103 is provided between the two; when the insulating pad reaches a predetermined temperature, the insulating pad expands and drives the contact portion of the positive brush assembly 4 to touch the extension portion, so that the fuse 8 is melted; one end of the negative brush assembly 5 is connected to the base plate 1 through a second wire 7.

[0037] Compared with the prior art, the brush holder assembly provided by the present invention has the following advantages:

[0038] The brush holder assembly provided by the present invention can stably install the insulating pad and the brush mechanism through the base plate 1, and can realize the conversion of energy through the arranged positive brush assembly 4 and negative brush assembly 5. Since one end of the positive brush assembly 4 in the present application is connected to the fuse 8 through the first wire 6, an extension portion made of a conductive material is formed on the base plate 1 and is spaced apart from the other end of the positive brush assembly 4, and the insulating pad in the present application is made of a heat-expanding material. Therefore, when an overload occurs, the temperature inside the electric device gradually increases, causing the insulating pad to expand due to the heat, thereby driving the positive brush assembly 4 to move in a direction close to the extension portion until the contact portion of the positive brush assembly 4 contacts the extension portion.

[0039] Preferably, the extension part in the present application is made of metal conductive material. Therefore, when the contact part of the positive brush assembly 4 contacts the extension part, a short-circuit current can be generated, causing the fuse 8 to melt, thereby reducing the problem of ablation caused by overload of the electric device to a certain extent.

[0040] And as Figure 1 As shown, the contact portion of the positive electrode brush assembly 4 in the present application is actually the position where the positioning seat 9 extends outward and is riveted to the bottom plate 1.

[0041] It should be noted that the present application does not actually achieve overload protection by short-circuiting the armature through the heat generated internally under the overload state, thereby short-circuiting the internal circuit and then melting the fuse 8, but rather by increasing the internal temperature under the overload state to cause the insulation pad to expand due to heat, thereby causing the internal circuit to short-circuit and the fuse 8 to melt, thereby completing the overload protection function. Therefore, the brush holder assembly provided by the present application is not limited by the current size. When the overload causes the internal temperature to rise to a certain level, the overload protection of the structure can be achieved. In addition, since the positive brush assembly 4 in the present application is connected to the fuse 8 through the first wire 6, the internal short-circuit point can be controlled to a certain extent, reducing the risk of ablation.

[0042] Preferably, the insulating pad in the present application is made of nylon material, which can react well when the temperature rises, thereby quickly realizing the overload protection function. However, it is not limited to nylon material. The linear expansion coefficient is within 1.0×10 -4 / K~1.4×10 -4 Other insulating materials of / K can be used as insulating pads in this application.

[0043] The base plate 1 in the present application is a circular ring structure, and the hollow portion formed in the middle can facilitate the armature to pass through and contact with the carbon brushes 11 distributed around it.

[0044] It should be noted here that, under overload condition, the internal temperature of the device gradually rises, and the insulating pad absorbs heat and expands as the temperature rises. The above-mentioned predetermined temperature is the temperature at which the insulating pad can begin to expand to push the contact part to move closer to the extension part.

[0045] Specifically, the extended portion includes a connecting section 1011, an inclined section 1012 and a contact section 1013; one end of the connecting section 1011 is connected to the base plate 1, and the other end is connected to one end of the inclined section 1012. The other end of the inclined section 1012 extends toward the direction close to the base plate 1 and is connected to one end of the contact section 1013. The contact section 1013 is located above the contact portion to form a gap 103.

[0046] Preferably, the extension portion and the bottom plate 1 in the present application are integrally formed, and the bottom plate 1 is made of insulating material.

[0047] Further preferably, the connecting section 1011 of the extension portion in the present application extends in the vertical direction, so that the inclined section 1012 and the contact section 1013 can be spaced apart from the bottom plate 1, and the Figure 4The inclined section 1012 shown in the figure can, on the one hand, reduce the gap 103 formed between the contact section 1013 and the contact portion; on the other hand, since the brush holder assembly in the present application is mainly used in the starter, and the starter is mostly used in the engine compartment of the car, the inclined section 1012 can improve the stability of the contact section 1013 to a certain extent, thereby avoiding the problem of vibration of the contact section 1013 when the car vibrates, resulting in contact with the contact portion and causing an erroneous short circuit.

[0048] It is necessary to add that, if Figure 2 As shown, in the present application, the extension portion extends away from the end connected to the base plate 1 toward the direction close to the fuse rod 8, so that the extension portion has a certain inclination, thereby further improving the strength and stability of the extension portion to a certain extent.

[0049] Among them, Figure 1 Combination Figure 2 As shown, when the brush holder assembly in the present application is applied to the starter, the positive brush assembly 4 in the present application includes a first brush assembly 401 and a second brush assembly 402, and the negative brush assembly 5 includes a third brush assembly 501 and a fourth brush assembly 502; the extension portion formed on the base plate 1 includes a first extension portion 101 formed corresponding to the first brush assembly 401 and a second extension portion 102 formed corresponding to the second brush assembly 402.

[0050] The brush holder assembly in the present application is mainly used in a starter, and therefore, the number of the positive electrode brush assembly 4 and the number of the negative electrode brush assembly 5 in the present application are both two.

[0051] Since the present application realizes short circuit by making the positioning seat 9 contact with the extension part due to the thermal expansion of the insulating pad, when the motor or starter is overloaded, uneven heating may easily cause the expansion speed and effect of the insulating pad to be different. The present application can correspond to the first brush assembly 401 and the second brush assembly 402 respectively by forming the first extension part 101 and the second extension part 102 on the bottom plate 1. Therefore, even if the thermal expansion speeds of the first insulating pad 2 and the second insulating pad 3 are different, as long as the expansion of one side pushes the corresponding positive brush assembly 4 to contact the extension part, a short circuit can be formed to achieve overload protection.

[0052] In this embodiment, preferably, Figure 1 Combination Figure 2 As shown, the insulating pad includes a first insulating pad 2 and a second insulating pad 3 which are symmetrically arranged, and the first insulating pad 2 and the second insulating pad 3 are both fan-shaped sheet structures; the first insulating pad 2 and the second insulating pad 3 are arranged opposite to each other, and the first brush assembly 401 and the third brush assembly 501 are arranged on the first insulating pad 2, and the second brush assembly 402 and the fourth brush assembly 502 are arranged on the second insulating pad 3.

[0053] Since the main bodies of most motors or starters are cylindrical structures, the cross-section of the base plate 1 in the present application is circular. By setting the first insulating pad 2 and the second insulating pad 3 on the base plate 1, the present application can, on the one hand, enable a positive brush assembly 4 and a negative brush assembly 5 to form a group, so that they can provide a current circuit stably without affecting each other during operation; on the other hand, since the first insulating pad 2 and the second insulating pad 3 are fan-shaped sheet structures, they can better fit with the base plate 1 and reduce space occupancy.

[0054] It should be noted that the first insulating pad 2 and the second insulating pad 3 in the present application are symmetrically arranged with the diameter of the bottom plate 1 as the symmetry axis. In order to further improve the stability of the overall structure, preferably, the first brush assembly 401 and the third brush assembly 501 on the first insulating pad 2 and the second brush assembly 402 and the fourth brush assembly 502 on the second insulating pad 3 in the present application are symmetrically arranged.

[0055] In the present application, the first brush assembly 401, the second brush assembly 402, the third brush assembly 501 and the fourth brush assembly 502 are arranged at intervals along the circumference of the base plate 1, and the first brush assembly 401 and the third brush assembly 501 are symmetrically arranged with the second brush assembly 402 and the fourth brush assembly 502 with the diameter of the base plate 1 as the symmetry axis.

[0056] Since the end of the carbon brush 11 away from the elastic member 10 protrudes from the positioning seat 9, the symmetrical arrangement of the first brush assembly 401 and the third brush assembly 501 and the second brush assembly 402 and the fourth brush assembly 502 can make the armature evenly stressed after the end of all the carbon brushes 11 away from the elastic member 10 is in contact with the input shaft of the armature.

[0057] It should be noted here that since the brush holder assembly in the present application is mainly used in the starter, preferably, the brush mechanism in the present application includes two positive brush assemblies 4, namely the first brush assembly 401 and the second brush assembly 402, and two negative brush assemblies 5, namely the third brush assembly 501 and the fourth brush assembly 502.

[0058] Specifically, Figure 2 As shown, in the present application, the fuse 8 includes a first connecting portion 801 and a second connecting portion 802, and the number of first wires 6 corresponds to the number of positive brush assemblies 4; the first connecting portion 801 is connected to an end of the first brush assembly 401 away from the first extension portion 101 through the first wire 6, and the second connecting portion 802 is connected to an end of the second brush assembly 402 away from the second extension portion 102 through the first wire 6.

[0059] The first connection part 801 can be connected to one end of the first brush assembly 401 through the first wire 6, and the second connection part 802 can be connected to one end of the second brush assembly 402 through the first wire 6, so that the first brush assembly 401 and the second brush assembly 402 do not interfere with each other, thereby improving the stability of the overall mechanism.

[0060] Preferably, if Figure 1 Combination Figure 2 As shown, in the present application, the positive brush assembly 4 and the negative brush assembly 5 both include a positioning seat 9, an elastic member 10 and a carbon brush 11; the positioning seat 9 is connected to the insulating pad and the base plate 1, the elastic member 10 is arranged in the positioning seat 9, one end of the carbon brush 11 is connected to one end of the elastic member 10, and the other end protrudes from the positioning seat 9.

[0061] The positioning seat 9 in the present application is positioned with the base plate 1 by riveting, and the insulating pad is sandwiched between the positioning seat 9 and the base plate 1, and the insulating pad is connected to the base plate 1 by riveting. The positioning seat 9 has a receiving cavity, and the elastic member 10 and the carbon brush 11 are arranged in the receiving cavity, and one end of the elastic member 10 is connected to the positioning seat 9, and the other end is connected to the carbon brush 11, so that the carbon brush 11 can slide relative to the positioning seat 9, and the end of the carbon brush 11 away from the elastic member 10 is protruded from the positioning seat 9, so that it can contact the armature arranged in the hollow part of the above-mentioned annular base plate 1.

[0062] It should be additionally explained here that the elastic member 10 in the present application is a spring.

[0063] Furthermore, if Figure 1 Combination Figure 2 As shown, in the present application, one end of the first wire 6 is connected to the carbon brush 11 of the positive brush assembly 4, and the other end is connected to the fuse 8, and one end of the second wire 7 is connected to the carbon brush 11 of the negative brush assembly 5, and the other end is connected to the base plate 1.

[0064] like Figure 2 As shown, in the present application, there are two first wires 6, which correspond to the first brush assembly 401 and the second brush assembly 402 respectively, and there are two second wires 7, which correspond to the third brush assembly 501 and the fourth brush assembly 502 respectively. Since the carbon brush 11 is in contact with the armature, connecting the fuse 8 with the carbon brush 11 through the first wire 6 can better conduct the current.

[0065] Preferably, if Figure 2 As shown, the present application also includes a bushing 12 , which is connected to the base plate 1 , one end of the fuse 8 passes through the bushing 12 to contact the first wire 6 , and the other end passes through the bushing 12 to be arranged.

[0066] The fuse 8 in the present application is a fuse rod, the bushing 12 is connected to the base plate 1 and has a positioning hole, one end of the fuse rod passes through the positioning hole and is located close to the first brush assembly 401 and the second brush assembly 402, and forms a first connecting portion 801 and a second connecting portion 802 correspondingly, and the other end of the fuse 8 is connected to the positive pole of the external power supply and can be connected through a wire.

[0067] In addition, the present invention also provides an electric device including the brush holder assembly.

[0068] By adopting the electric device of the brush holder assembly provided in the present application, short-circuit protection can still be performed under low current conditions, thereby reducing the risk of ablation. In addition, the brush holder assembly provided in the present application can also control the internal short-circuit point during overload, thereby improving the safety of the overall device.

[0069] It should be additionally explained here that the electric device in the present application is a motor or a starter or other device using a carbon brush 11 and a brush holder assembly structure.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A brush holder assembly, characterized in that: It includes a base plate, an insulating pad, a brush mechanism and a fuse; The insulating pad is made of a heat-expanding material and is arranged on the bottom plate. The brush mechanism is arranged on the insulating pad. The bottom plate is formed with an extension portion, and the extension portion is made of a conductive material. The brush mechanism comprises a positive brush assembly and a negative brush assembly, one end of the positive brush assembly is electrically connected to the fuse, and the extension portion corresponds to the contact portion of the other end of the positive brush assembly with a gap therebetween; When the insulating pad reaches a predetermined temperature, the insulating pad expands and drives the contact portion of the positive electrode brush assembly to touch the extension portion, so that the fuse is melted.

2. The brush holder assembly according to claim 1, characterized in that: The thermal expansion material of the insulating pad has a linear expansion coefficient of 1.0×10 -4 / K~1.4×10 -4 / K insulating material.

3. The brush holder assembly according to claim 1, characterized in that: The extension portion includes a connecting section, an inclined section and a contact section; One end of the connecting section is connected to the bottom plate, and the other end is connected to one end of the inclined section. The other end of the inclined section extends toward the bottom plate and is connected to one end of the contact section. The contact section is located above the contact portion to form the gap.

4. The brush holder assembly according to claim 1, characterized in that: The positive electrode brush assembly includes a first brush assembly and a second brush assembly, and the negative electrode brush assembly includes a third brush assembly and a fourth brush assembly; The extension portion formed on the bottom plate includes a first extension portion formed corresponding to the first brush assembly and a second extension portion formed corresponding to the second brush assembly; The insulating pad comprises a first insulating pad and a second insulating pad which are symmetrically arranged, and both the first insulating pad and the second insulating pad are in a fan-shaped sheet structure; The first insulating pad is arranged opposite to the second insulating pad, and the first brush assembly and the third brush assembly are arranged on the first insulating pad, and the second brush assembly and the fourth brush assembly are arranged on the second insulating pad.

5. The brush holder assembly according to claim 4, characterized in that: The first brush assembly and the third brush assembly located on the first insulating pad are symmetrically arranged with the second brush assembly and the fourth brush assembly located on the second insulating pad.

6. The brush holder assembly according to claim 5, characterized in that: The fuse comprises a first connecting portion and a second connecting portion, a first wire is connected between the positive electrode brush assembly and the fuse, and the number of the first wires corresponds to the number of the positive electrode brush assemblies; The first connecting portion is connected to an end of the first brush assembly away from the first extension portion through the first conductive wire, and the second connecting portion is connected to an end of the second brush assembly away from the second extension portion through the first conductive wire.

7. The brush holder assembly according to claim 6, characterized in that: The positive electrode brush assembly and the negative electrode brush assembly both include a positioning seat, an elastic member and a carbon brush; The positioning seat is connected to the insulating pad and the bottom plate, the elastic member is arranged in the positioning seat, one end of the carbon brush is connected to one end of the elastic member, and the other end protrudes from the positioning seat.

8. The brush holder assembly according to claim 7, characterized in that: A second wire is connected between the negative electrode brush assembly and the bottom plate, and the number of the second wires corresponds to the number of the negative electrode brush assemblies; One end of the first wire is connected to the carbon brush of the positive brush assembly, and the other end is connected to the fuse; one end of the second wire is connected to the carbon brush of the negative brush assembly, and the other end is connected to the bottom plate.

9. The brush holder assembly according to claim 6, characterized in that: It also includes a bushing, which is connected to the bottom plate. One end of the fuse passes through the bushing to contact the first wire, and the other end passes through the bushing.

10. An electric device, characterized in that: A brush holder assembly comprising any one of claims 1 to 9.

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