CN211908570U - Brushless motor and power tool containing the same - Google Patents

Abstract

The utility model discloses a brushless motor and electric tool who contains it. Wherein the brushless motor (22) comprises: a housing (34) at least partially housing the stator and the rotor; an end cap (40) located adjacent an end of the brushless motor; and a circuit board (32) including a controller for the brushless motor. The circuit board is located outside an area defined by the end cap and the housing. In the power tool, a brushless motor is fixedly mounted on a tool housing and is adapted to drive one or more movable components in the power tool. Since the circuit board is placed outside the case and the end caps, there is no need to provide a separate heat sink for the circuit board, and the end caps on which the circuit board is mounted become large heat sinks for the circuit board. This provides improved heat dissipation efficiency for the circuit board and the stator/rotor of the motor.

Description

Brushless motor and power tool containing the same

technical field

The utility model relates to an electric tool, in particular to a battery-powered electric tool with a brushless motor and its internal structure.

Background technique

Power tools are used in a wide variety of applications such as construction, building works and interior decoration. These power tools use the drive power generated by the on-board drive motor to provide the user with the necessary tool functions. At the same time, power tools are generally made compact and lightweight so that users can carry and maneuver them without difficulty.

However, the internal structure of conventional power tools is often complex and manufactured out of order in some way. For example, many conventional power tools use brushless motors as drive motors, which require one or more circuit boards to carry motor sensors and motor controllers for proper operation of the brushless motor. However, the circuit board is usually placed within the housing of the electric motor, and special heat dissipation components (eg heat sinks) must be designed for the circuit board and also placed within the housing. This increases the complexity of the motor structure and reduces heat dissipation efficiency.

Utility model content

In view of the foregoing background, it is an object of the present invention to provide an alternative power tool design that eliminates or at least alleviates the aforementioned technical problems.

Accordingly, in one aspect of the present invention, there is provided a brushless motor comprising a housing at least partially housing the stator and rotor, end caps located adjacent ends of the brushless motor; and a circuit board comprising the brushless motor Motor controller. The circuit board is located outside the area defined by the end cap and the housing.

Preferably, the circuit board is further from the stator or rotor than the end caps in the longitudinal direction defined by the motor shaft.

More preferably, the circuit board is located at the outermost position at the end of the brushless motor relative to the rotor or stator.

According to a specific embodiment, the circuit board has substantially the same contour as the end cap.

According to another specific embodiment, the circuit board further includes a plurality of through holes adapted to receive posts on the end cap so that the circuit board is securely mounted on the end cap.

According to a variant of the preferred embodiment, the circuit board further comprises a plurality of surface mount components arranged on the surface of the circuit board.

According to another variant of the preferred embodiment, the Hall sensor, the power control device and the logic controller are arranged on the circuit board.

According to a further variation of the preferred embodiment, the end caps are manufactured using die castings.

According to another aspect of the present invention, there is provided a power tool including a tool housing and the brushless motor as described above. The brushless motor is fixedly mounted on the tool housing and is adapted to drive one or more movable parts in the power tool.

The present invention has many advantages, the main one being that the brushless motor according to the present invention provides improved heat dissipation for the circuit board and the internal components of the motor, such as the stator and rotor. Since the circuit board is placed outside the motor housing and end caps, there is no need for a separate heat sink for the circuit board, instead the end cap for the circuit board to mount to becomes a large heat sink for the circuit board. The end caps are preferably made by die casting to improve heat dissipation efficiency. Circuit boards exposed to the outside of the motor structure also contribute to better heat dissipation from the surrounding environment itself.

Since the circuit board is no longer located within the motor, especially adjacent to the stator or rotor, an air flow path is now created that begins and ends around the two end caps of the motor. The air flow path is formed by the gap between the end caps and the stator/rotor, and since the circuit board is placed outside the motor structure. This air flow path further improves the cooling efficiency of the motor stator and rotor.

Description of drawings

The foregoing and further features of the present invention will become apparent from the following description of the preferred embodiments, provided by way of example only in connection with the accompanying drawings, wherein:

FIG. 1 is a perspective view of a hand-held power tool according to a first embodiment of the present invention.

FIG. 2a is a perspective view showing the structure of the drive motor in the power tool of FIG. 1 .

Figure 2b shows a perspective view of the structure in Figure 2a from another perspective.

Figure 2c shows a perspective view of the structure of Figure 2a from another perspective.

Figure 3 is a side view of the structure of Figure 2a.

Figure 4 is a cross-sectional view of the structure of Figure 2a along a plane in which the axis of rotation of the motor shaft lies.

Figure 5a is a front view of the circuit board in the configuration of Figure 2a.

Figure 5b is a rear view of the circuit board of Figure 5a.

FIG. 6 shows a side view of the internal structure of a power tool according to another embodiment of the present invention.

Detailed ways

In the following and in the claims in the foregoing description of the invention, unless the context requires otherwise due to explicit language or a requisite meaning, variations of the word "comprise" or "comprise" are used to include the meaning that The presence of the stated features does not preclude the presence or addition of other features in various embodiments of the invention.

As used herein and in the claims, unless stated otherwise, "coupled" or "connected" means electrically coupled or connected, directly or indirectly, by one or more electrical devices.

Terms such as "horizontal", "vertical", "upward", "downward", "above", "below" and similar terms are used herein for the purpose of describing the present invention in its normal orientation of use. It is not intended to limit the invention to any particular orientation.

Referring now to FIG. 1, a first embodiment of the present invention is a power tool designed to be hand-held. The power tool has a housing that includes a body portion 20 and a handle portion 28 . A drive motor 22 is mounted inside the body portion 20 and is configured to drive one or more movable components in the power tool, such as any intermediate gear mechanism (not shown) and ultimately the tool bit holder twenty four. The body portion 20 extends substantially in an axial direction defined by a motor shaft (not shown) of the drive motor 22 . The handle portion 28 is connected to and extends from the body portion in a generally downward direction, but is inclined from a vertical direction perpendicular to the axial direction. A trigger 26 is disposed on the handle portion 28, wherein the trigger 26 is exposed to the outside for user operation to turn on/off the power tool. At the bottom of the handle portion 28, there is a battery pack 30 that is removably attached to the power tool to supply power to the circuits inside the power tool.

Turning now to Figures 2a-2c and Figure 3, the structure of the drive motor of the power tool as described above is clearly shown, wherein other components of the power tool are hidden. The drive motor is a brushless DC motor that includes two end caps 38, 40 located generally at both ends of the motor. The drive motor also includes a housing 34 configured to at least partially house essential parts of the motor, such as a rotor and a stator (neither shown). The housing 34 is located between the two end caps 38 , 40 . In particular, grooves (not shown) are formed on the outer circumference of the housing 34 , and these grooves receive a plurality of elongated screws 44 , the ends of which respectively extend into the housing 34 . The end cap 38 and the end cap 40 are thus firmly connected together by the screws 44 . A fan 42 is mounted on one end of the motor, and the fan 42 is covered by the end cover 38 . The end caps 38 , 40 and the housing 34 are aligned along an axis of rotation defined by the motor shaft 52 .

The circuit board 32 of the motor is arranged at the other end of the motor adjacent to the end cover 40 . Specifically, the circuit board 32 is exposed outside the housing 34 and the end caps 40, and is actually located at the outermost positions at each end of the motor. In other words, the circuit board 32 is further from the stator or rotor than the end caps 40 in the longitudinal direction defined by the motor shaft 52. Because the circuit board 32 is not placed within the housing 34 and end cap 38 . In Figures 2a-2b, the dimensions of circuit board 32 are slightly larger than the dimensions of housing 34 or end caps 38,40. The contour of the upper part 41 of the circuit board 32 closely follows the contour of the end cap 40 so that they have the same shape. On the other hand, the lower part 43 of the circuit board 32 extends beyond the end cap 40 . Circuit board 32 is mounted to circuit board 32 by extending one or more posts 36 from end cap 40 into corresponding through holes (not shown) to securely hold circuit board 32 on end cap 40 . On the circuit board 32, there are a plurality of surface mount (SMT) components 50, such as electrically connected resistors, ICs, and capacitors. Connection wires 47 extend from the circuit board 32 and have connectors 46 on their free ends. The connection wires 47 allow the circuit board 32 to be electrically connected to other components in the power tool, such as the battery pack or trigger described in FIG. 1 .

Turning now to Figure 4, in cross-sectional view it can be seen that the shaft 52 is rotatably supported by bearings 54 on the end caps 38, 40, respectively. Rotor 58 is mounted on motor shaft 52, which contains magnets 64. Outside the rotor 58 is a stator 62 containing windings 60 that mate with magnets 64 in the rotor 58 . The structure and working principles of stator and rotor structures in brushless motors are well known to the skilled person and therefore no further description is provided here. It should be noted, however, that the motor configuration shown in FIG. 4 effectively provides the air path indicated by arrow 66 . Air from the outside environment can enter the interior of the motor between the end caps 38, 40 and the rotor/stator from one end of the motor and exit the other end. Such an air path can be created because there is no circuit board placed inside the motor that would otherwise block the air flow. In the absence of a circuit board, sufficient clearance is allowed between each end cap 38, 40 and the rotor/stator so that air can flow through such clearance.

The circuit board 32 is shown in Figures 5a and 5b, respectively. The circuit board 32 has a substantially oval shape, and there are SMT components 50 as well as non-SMT components on the circuit board 32 . For example, the SMT element 50 includes the microcontroller 53 and the non-SMT element includes the capacitor 55 . In the SMT element 50 and the non-SMT element, there are Hall sensors, power control means and logic controllers arranged on the circuit board.

In the above-described embodiment, the circuit board 32 is placed outside the motor housing and end caps, so there is no need to configure a separate heat sink for the circuit board 32 . Instead, since the circuit board 32 is directly mounted on the end cap 40 , the end cap 40 acts as a heat sink for the circuit board 32 . In other words, the end cap 40 becomes a much larger heat sink than the individual heat sinks used in conventional brushless motors. Such a configuration not only simplifies the structure of the motor, but also greatly improves the heat dissipation efficiency of the motor. As mentioned above, heat dissipation is further improved by the air paths created between the end caps 38, 40 and the rotor/stator.

Turning now to FIG. 6, a portion of a power tool according to another embodiment of the present invention is shown. Both the drive motor 122 and the main body portion 120 are arranged in the axial direction of the motor shaft (not shown). The drive motor 122 is a brushless DC motor located at the rear end of the body portion 120 and covered by the end cap 140 of the body portion 120. The drive motor 122 includes a housing 134 made by die casting. Housing 134 supports other components of motor 122 on body portion 120 . The circuit board 132 of the electric motor 122 is arranged at one end of the electric motor 122 adjacent to the end cap 140 . The circuit board 132 is mounted on the housing 134 by having one or more posts 136 extending from the housing 134 into corresponding through holes (not shown) in the circuit board 132, thereby securely holding the circuit board 132. Therefore, the circuit board 132 is mechanically connected to the drive motor 122 . On the circuit board 132, there are a number of surface mount (SMT) components (not shown) such as electrically connected resistors, ICs and capacitors.

Thus, the exemplary embodiments of the present invention have been fully described. Although the description relates to specific embodiments, it will be apparent to those skilled in the art that the present invention may be practiced by varying these specific details. Therefore, the present invention should not be construed as limited to the embodiments set forth herein.

While the invention has been illustrated and described in detail in the accompanying drawings and the foregoing description, which are likewise to be regarded in an illustrative rather than a restrictive sense, it is to be understood that only exemplary embodiments have been shown and described and not In any way limit the scope of the present invention. It will be appreciated that any feature described herein can be used with any embodiment. The illustrative embodiments do not exclude each other or other embodiments not recited herein. Accordingly, the present invention also provides embodiments comprising combinations of one or more of the above-described illustrative embodiments. Modifications and variations of the invention described herein may be made without departing from the spirit and scope of the invention, therefore, these limitations should only be imposed as indicated in the appended claims.

Claims (9)

1. A brushless motor comprising: a) a housing at least partially housing the stator and rotor; b) an end cap located adjacent one end of said brushless motor; and c) a circuit board including a controller for said brushless motor; Its characteristics are: The circuit board is located outside the area defined by the end cap and the housing. 2. The brushless motor of claim 1, wherein the circuit board is further away from the stator or rotor than the end cap in a longitudinal direction defined by the motor shaft. 3. The brushless motor of claim 2, wherein the circuit board is located at an outermost position at the end of the brushless motor relative to the rotor or stator. 4. The brushless motor according to any one of claims 1-3, wherein the circuit board has substantially the same contour as that of the end cap. 5. The brushless motor of claim 1, wherein the circuit board further comprises a plurality of through holes, the through holes are adapted to receive the posts on the end cap, so that the circuit board is firmly installed on the end cap. 6 . The brushless motor of claim 1 , wherein the circuit board further comprises a plurality of surface mount components, and the plurality of surface mount components are arranged on a surface of the circuit board. 7 . 7. The brushless motor according to claim 1, wherein a hall sensor, a power control device and a logic controller are arranged on the circuit board. 8. The brushless motor according to claim 1, wherein the end cover is made of die casting. 9. A power tool, comprising a tool housing, characterized in that: The power tool further comprises a brushless motor as claimed in any one of claims 1 to 8; the brushless motor is fixedly mounted on the tool housing and is adapted to drive one of the power tools or Multiple movable parts.

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