WO2018209605A1

WO2018209605A1 - Brushless electric tool

Info

Publication number: WO2018209605A1
Application number: PCT/CN2017/084740
Authority: WO
Inventors: 刘佰祥; 陈艳华; 周述宇
Original assignee: 深圳和而泰智能控制股份有限公司
Priority date: 2017-05-17
Filing date: 2017-05-17
Publication date: 2018-11-22
Also published as: CN108702111A

Abstract

A brushless electric tool. The brushless electric tool comprises a main control circuit (30), a power drive circuit (20), and a brushless motor (10). The main control circuit and the power drive circuit are disposed on the same circuit board (100), the brushless motor is electrically connected to the power drive circuit, and the main control circuit is configured to control the power drive circuit to drive the brushless motor. The electric tool reduces connection lines between a power drive circuit and a main control circuit, resolves the problem of complicated circuitry in current electric tool control solutions, and reduces space occupied by circuit boards and wirings in electric tool housings, leaving more space for placement of other electric tool components and thus allowing product upgrade. In addition, the space inside the housing of the electric tool is large, preventing components in the housing from colliding with each other and being damaged during installation of the electric tool, achieving high reliability.

Description

Brushless power tool

Technical field

Embodiments of the present application relate to the field of power tools, and in particular, to a brushless power tool.

Background technique

In recent years, with the rapid development of the economy, the power tool industry has developed rapidly. Power tools are widely used in aerospace, high-speed rail construction, shipbuilding, automobile manufacturing, advanced equipment manufacturing, road construction, decoration, wood processing and metal processing. . According to the technical requirements and application fields of the product, it can be divided into three levels, namely industrial grade, professional grade and family grade. Among them, industrial-grade power tool products are mainly used in workplaces with high processing precision and high environmental protection requirements, such as aerospace field, high-end equipment manufacturing, etc., with high technical requirements; professional-grade power tool products generally require high power and motor. High speed, long motor life, continuous work for a long time, etc.; household-grade power tools are mainly used in applications where accuracy is not high, continuous running time is not long, and simple application, such as simple application, decoration and decoration, technology Low requirements.

The electrical parts of the existing professional-grade brushless power tools are usually composed of a main part of a power supply battery pack, a main control circuit, a power drive circuit, a speed control switch, and a brushless motor.

In the process of implementing the present invention, the inventors have found that at least the following problems exist in the related art: the current brushless power tool adopts a main control circuit and a power drive circuit portion as different independent circuit portions, and an electrical connection line between the two. It is complicated, and the circuit board part and the line part occupy a large amount of space in the power tool housing, so that it is easily damaged when installed, and the reliability is relatively low.

Summary of the invention

The technical problem mainly solved by the embodiments of the present application is to provide a brushless electric tool with simple wiring, small electric space occupied by electric tools, and high reliability.

In order to solve the above technical problem, a technical solution adopted by the embodiment of the present application is: a brushless power tool including a main control circuit, a power driving circuit, and a brushless motor, wherein the main control circuit and the power driving circuit are located in the same The brushless motor is electrically connected to the power driving circuit, and the main control circuit is configured to control the power driving circuit to enable the power driving circuit to drive the Brushless motor works.

Optionally, the power driving circuit comprises a plurality of metal-oxide semiconductor field effect transistors, and the metal-oxide semiconductor field effect transistors adopt a direct insertion type package structure.

Optionally, the brushless power tool further includes a heat dissipating unit disposed opposite to the circuit board, wherein the plurality of metal-oxide semiconductor field effect transistors are fixedly disposed on the heat dissipating unit, the metal-oxide semiconductor field An insulating thermally conductive gasket is disposed between the effect transistor and the heat dissipation unit.

Optionally, the metal-oxide semiconductor field effect transistor includes a fixed end portion, and the fixed end portion is provided with a mounting hole, and the metal-oxide semiconductor field effect transistor passes through the mounting hole through a nail And the insulating and thermally conductive gasket is fixed on the heat dissipation unit.

Optionally, the brushless motor includes an opposite rotor and a stator, and the stator is fixedly connected to a side of the heat dissipating unit away from the metal-oxide semiconductor field effect transistor, and the rotor is away from a side of the stator. It is fixedly connected to a cooling fan that cools the brushless motor.

Optionally, the circuit board includes a circular portion and a connecting portion, the heat dissipating unit is a cylindrical structure, a circular portion of the circuit board is disposed on a bottom surface of the heat dissipating unit, and another bottom surface of the heat dissipating unit Fixedly coupled to the stator, the diameter of the circular portion coincides with the cross-sectional diameter of the heat dissipating unit and the diameter of the stator.

Optionally, the brushless power tool further includes a position sensor detecting circuit, and the position sensor detecting circuit is located on the circuit board.

Optionally, the brushless power tool further includes a position sensor detecting circuit, the circuit board further includes a position sensor detecting circuit interface, and the position sensor detecting circuit is connected to the circuit board through the position sensor detecting interface.

Optionally, the circuit board is a multi-layer structure, and a top layer of the circuit board is provided with a solder paste layer.

Optionally, the solder paste layer is provided with a copper foil.

The beneficial effects of the embodiments of the present application are: the embodiment of the present application sets the power driving circuit and the main control circuit on the same circuit board, which saves the connection between the power driving circuit and the main control circuit, and solves the current power tool control scheme. The problem of complicated lines. The space occupied by the circuit board and the wiring in the power tool housing is saved, and more space is reserved for the power tool to place other components for the purpose of upgrading the product, and the space inside the power tool housing is large, which can prevent the power tool from being installed. The components in the housing collide with each other and are highly reliable.

DRAWINGS

1 is a schematic view of an electrical part of a brushless power tool according to an embodiment of the present application;

2 is a schematic view of an electrical part of a brushless power tool according to an embodiment of the present application;

3 is a schematic exploded view of a circuit board, a field effect transistor, and a heat dissipation unit of a brushless power tool according to an embodiment of the present application;

4 is a schematic exploded view of a stator, a rotor, a heat dissipation fan, and a heat dissipation unit of a brushless power tool according to an embodiment of the present application;

FIG. 5 is a schematic structural view of a solder paste layer and a copper foil according to an embodiment of the present application.

detailed description

The technical solutions in the embodiments of the present application are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present application. It is a partial embodiment of the invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

Please refer to FIG. 1 to FIG. 4 together, wherein FIG. 1 and FIG. 2 are schematic diagrams of electrical parts, and FIG. 3 and FIG. 4 are schematic diagrams of structural parts. As shown in FIG. 1 and FIG. 2, the brushless electric tool of the present invention is electrically The part includes a brushless motor 10, a power driving circuit 20, a main control circuit 30 and a position sensor detecting circuit 40. The power driving circuit 20 is for driving the brushless motor 10, and the main control circuit 30 is for controlling the switch in the power driving circuit 20. The tube (not shown) is turned on and off to control the power drive circuit 20 to drive the brushless motor 10, and the position sensor detecting circuit 40 is used to detect the position of the rotor when the brushless motor 10 is in operation.

The power driving circuit 20, the main control circuit 30 and the position sensor detecting circuit 40 are located on the same circuit board 100. The circuit board 100 is further provided with a power interface J1 and a peripheral electrical component interface J2. The power interface J1 is used to connect the power supply battery pack BT. In the existing solution, since the main control circuit and the power drive circuit each occupy one circuit board, one of the power interfaces on one circuit board has only a small current loop, and the other The power interface on the circuit board is a large current loop. In this embodiment, since the main control circuit 30 and the power drive circuit 20 are integrated on the same circuit board, only one power interface J1 is a large current loop. When the power tool is working, a large current will be generated in the power line part, and a large current will generate a large electromagnetic interference. The power interface J1 is set as an independent power supply interface, which can avoid interference with other line parts when the high current is working.

The peripheral electrical component interface J2 is used for connecting peripheral electrical components such as LED lights, speed control switches, various key switches, and the peripheral electrical components such as LED lights, speed control switches, and various key switches are reserved on the circuit board 100. The interface J2 and the electrical components on the circuit board 100 are electrically connected to each other, and the structure is simpler and more convenient. The peripheral electrical component interface J2 also includes a protocol data line that communicates with the battery pack BT, facilitating the management and monitoring of the battery pack BT by the main control circuit 30, and providing a smarter and safer power supply.

In practical applications, the peripheral electrical component interface J2 can be designed as a way of plugging and unplugging the connector, facilitating line connection and maintenance, and directly soldering the wires of the peripheral electrical components to the circuit board 100.

A fuse F1 is also connected between the power interface J1 and the battery pack BT. When the electrical part of the power tool is short-circuited or electrically defective, the fuse is blown to provide a reliable safety protection mechanism for the power tool.

The embodiment of the present application sets the power driving circuit 20 and the main control circuit 30 on the same circuit board 100, which saves the connection between the power driving circuit 20 and the main control circuit 30, and solves the complicated circuit in the current power tool control scheme. problem. The space occupied by the circuit board and the wiring in the power tool housing is saved, and more space is reserved for the power tool to place other components for the purpose of upgrading the product, and the space inside the power tool housing is large, which can prevent the power tool from being installed. The components in the housing collide with each other and are highly reliable.

Alternatively, in other embodiments of the brushless power tool, the position sensor detection circuit 40 may not be integrated on the circuit board 100. The position sensor detecting circuit 40 may be disposed on another circuit board, for example, separately disposed on a circuit board, and then the position sensor detecting circuit interface J3 is disposed on the circuit board 100, as shown in FIG. Since some of the brushless motors are provided with the position sensor detecting circuit 40 at the time of shipment, in this case, only the position sensor detecting circuit 40 provided by the board is detected by the position sensor detecting circuit interface J3 and the circuit on the circuit board 100. Other components on the board 100 enable electrical connection. This structure is also more concise and convenient. 1 is a scheme in which a position sensor detecting circuit is integrated on a circuit board 100, and FIG. 2 is a scheme in which a position sensor detecting circuit is not integrated on the circuit board 100. Integrating the position sensor on the circuit board 100 saves a separate board and saves space.

Alternatively, in other embodiments of the brushless power tool, it is also possible to use no fuses or use other safety devices.

Alternatively, in other embodiments of the brushless power tool, in the case where the battery pack BT is not required to be managed and monitored, the peripheral electrical component interface J2 may not include the protocol data line that communicates with the battery pack BT.

Referring to FIG. 3, the switching transistor in the power driving circuit can adopt a metal-oxide semiconductor field effect. Transistor 21 (hereinafter referred to as a field effect transistor). In this embodiment, the field effect transistor 21 is of a direct insertion type package structure, and FIG. 3 shows a specific mounting position of the six field effect transistors 21 on the circuit board 100. The pins 213 of the six field effect transistors are fixed on the circuit board 100.

The in-line type field effect transistor 21 includes a fixed end portion 214, and the fixed end portion 214 is provided with a mounting hole 211. In order to dissipate the field effect transistor 21, the field effect transistor 21 may be provided with a heat dissipation unit 60. For the in-line type field effect transistor, as shown in FIG. 3, the field effect transistor 21 can be fixed to the heat dissipation unit 60 by a screw passing through a mounting hole 211 on the fixed end portion 214 of the field effect transistor 21. An insulating thermal pad 50 is disposed between the field effect transistor 21 and the heat dissipation unit 60 to electrically isolate the field effect transistor 21 and the heat dissipation unit 60, and the screw can pass through the insulating thermal pad 50 at the same time to prevent the insulating thermal pad 50 from coming off the field. Effect transistor 21.

It should be noted that FIG. 3 is an exploded view of a circuit board, a field effect transistor, and a heat dissipation unit of the brushless power tool according to an embodiment of the present invention. In actual use, the circuit board 100 and the heat dissipation unit 60 are oppositely disposed through The field effect transistors 21 are fixed together.

The heat dissipation unit 60 may be a heat sink or a heat sink.

The field effect transistor 21 adopting the in-line package can directly fix the field effect transistor 21 on the heat sink (or heat sink), and can greatly reduce the conduction heat resistance between the field effect transistor 21 and the heat sink (or heat sink). Increasing the thermal conductivity between the two greatly increases the thermal conductivity of the field effect transistor 21. Moreover, since the field effect transistor 21 of the in-line type is used, the occupied space is small, and sufficient space is left on the circuit board to take a large current, and the influence of electromagnetic interference on the main control circuit 30 is prevented. Compared with the chip type field effect transistor 21, the driving scheme is not only lower in cost, simple, and easy to manufacture in PCBA, but also has good reliability, stability, and good heat dissipation performance.

Optionally, in other embodiments, the field effect transistor may also adopt a chip package structure, solder the field effect transistor chip to the circuit board, and then screw the circuit board to the heat sink or the heat sink. And an insulating thermal pad is placed between the field effect transistor and the heat sink, but this heat treatment method has a large conduction heat resistance, so that the thermal conductivity is small, and the heat accumulation inside the field effect transistor cannot be fast and reliable. Dissipated through the effective heat transfer channel. When the field effect transistor works for a long time through a large current, it is easy to cause the accumulation of thermal energy inside the field effect transistor to reach the avalanche energy limit of the field effect transistor and avalanche breakdown, resulting in burning of the device and the line. .

As shown in FIG. 4, the brushless motor 10 includes a rotor 12 and a stator 11 which are oppositely disposed. The stator 11 is fixedly connected to a side of the heat dissipation unit 60 remote from the circuit board 100, and the rotor 12 is away from the stator 11. The side is fixedly connected to the cooling fan 200. That is, the fan 12 is fixedly coupled to the fan 200 at one end thereof, and the other end of the rotor 12 is configured to extend into the interior of the stator 11. One end of the stator 11 is for receiving the rotor 12, and the other end is provided with a heat dissipating unit 60. The heat dissipation unit 60 is for dissipating heat from the field effect transistor 21 (not shown in FIG. 4), and the fixed end portion 214 of the field effect transistor 21 is fixed on the heat dissipation unit 60 while the pin 213 is fixed on the circuit board 100.

The heat dissipating fan 200 functions to dissipate the heat of the brushless motor and prevent the motor from being damaged due to overheating during the operation of the brushless motor. In the embodiment, the heat dissipating unit 60 and the circuit board 100 are fixed to the stator 11 as a whole, and The brushless motor 10 is connected as a unitary structure, so that when the rotor 12 of the brushless motor 10 is operated, the blades of the cooling fan 200 are driven to generate wind power, and the direction of the wind is blown from the rotor 12 of the brushless motor 10. The portion of the stator 11 that is blown toward the heat dissipating unit 60 of the field effect transistor 21 accelerates the heat dissipation of the field effect transistor 21 and the heat dissipation of the circuit board 100, thereby achieving a good heat dissipation effect, so that the internal temperature of the field effect transistor 21 is made. The I d current (drain current) that rises and flows through the internal can reach a self-balancing state. It further enhances the stability and reliability of the product, while prolonging the life of the product and the time for continuous operation of high current. In this embodiment, the heat dissipating unit 60 has a cylindrical structure, one bottom surface of which is fixedly connected to the stator 11 and the other bottom surface is fixedly connected to the circuit board 100. The circuit board 100 includes a circular portion 101 and a connecting portion 102. The diameter of the circular portion 101, the diameter of the bottom surface of the heat radiating unit 60, and the diameter of the stator 11 coincide.

It should be noted that FIG. 4 is a schematic diagram of the explosion of the stator, the rotor and the cooling fan of the brushless power tool according to the embodiment of the present invention. In actual use, the rotor 12 is disposed inside the stator 11.

The heat dissipation unit 60 has a cylindrical structure, and the circuit board 100 includes a circular portion 101, and the diameter of the circular portion, the diameter of the bottom surface of the heat dissipation unit, and the diameter of the stator 11 are kept uniform, so that the space occupied by the heat dissipation unit and the circuit board can be reduced. Further saving the space inside the casing of the brushless power tool.

Optionally, in other embodiments, the heat dissipating unit may not be fixed on the stator but placed in other positions.

Optionally, in other embodiments, the heat sink may not be a cylindrical structure, and may be, for example, a rectangular parallelepiped or a rectangular parallelepiped structure. The circuit board may also not include a circular portion but a rectangular or square circuit board. The diameter of the circular portion, the diameter of the bottom surface of the heat radiating unit, and the diameter of the stator 11 may also be different.

Optionally, the circuit board has a multi-layer structure. As shown in FIG. 5, the top layer of the circuit board is further provided with a solder paste layer 103, and the solder paste layer 103 is provided with a copper foil 104. Design solder paste layer and copper foil for adding The thickness of the large conductor greatly enhances its ability to take large currents.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; in the idea of the present application, the technical features in the above embodiments or different embodiments may also be combined. The steps may be carried out in any order, and there are many other variations of the various aspects of the present application as described above, which are not provided in the details for the sake of brevity; although the present application has been described in detail with reference to the foregoing embodiments, The skilled person should understand that the technical solutions described in the foregoing embodiments may be modified, or some of the technical features may be equivalently replaced; and the modifications or substitutions do not deviate from the embodiments of the present application. The scope of the technical solution.

Claims

A brushless power tool comprising a main control circuit, a power drive circuit and a brushless motor, wherein the main control circuit and the power drive circuit are on the same circuit board, the brushless motor and the power The driving circuit is electrically connected, and the main control circuit is configured to control the power driving circuit to cause the power driving circuit to drive the brushless motor to operate.
The brushless power tool according to claim 1, wherein said power driving circuit comprises a plurality of metal-oxide semiconductor field effect transistors, and said metal-oxide semiconductor field effect transistors employ a direct insertion type package structure.
The brushless power tool according to claim 2, wherein the brushless power tool further comprises a heat dissipating unit disposed opposite to the circuit board, wherein the plurality of metal-oxide semiconductor field effect transistors are fixedly disposed on An insulating thermally conductive gasket is disposed between the metal-oxide semiconductor field effect transistor and the heat dissipation unit on the heat dissipation unit.
The brushless power tool according to claim 3, wherein said metal-oxide semiconductor field effect transistor comprises a fixed end portion, said fixed end portion is provided with a mounting hole, said metal-oxide semiconductor field The effect transistor is fixed to the heat dissipation unit through a pin through the mounting hole and the insulating thermally conductive gasket.
A brushless power tool according to claim 3, wherein said brushless motor comprises oppositely disposed rotors and stators, said stator and said heat dissipating unit being fixed away from a side of the metal-oxide semiconductor field effect transistor Connected, one side of the rotor away from the stator is fixedly connected to a cooling fan that dissipates heat from the brushless motor.
The brushless power tool according to claim 5, wherein the circuit board comprises a circular portion and a connecting portion, the heat dissipating unit has a cylindrical structure, and a circular portion of the circuit board is disposed at the heat dissipating unit A bottom surface of the heat dissipating unit is fixedly connected to the stator, and a diameter of the circular portion is consistent with a cross-sectional diameter of the heat dissipating unit and a diameter of the stator.
The brushless power tool according to any one of claims 1 to 6, wherein the brushless power tool further comprises a position sensor detecting circuit, and the position sensor detecting circuit is located on the circuit board.
A brushless power tool according to any one of claims 1 to 6, wherein said none The brush power tool further includes a position sensor detection circuit, the circuit board further including a position sensor detection circuit interface, the position sensor detection circuit being coupled to the circuit board through the position sensor detection interface.
The brushless power tool according to claim 8, wherein said circuit board has a multilayer structure, and a top layer of said circuit board is provided with a solder paste layer.
The brushless power tool according to claim 9, wherein the solder paste layer is provided with a copper foil.