Brushless direct current motor end cover

Abstract

An end cap for a brushless motor dissipates heat from a controller and switching elements of the motor through fins in the end cap. The end cap can be directly or thermally coupled to the controller and switching elements to dissipate heat through the fins.

Description

TECHNICAL FIELD

[0001] The present application relates generally to end caps. More specifically, the present application relates to brushless DC motor end caps having heat dissipation structures. BACKGROUND

[0002] Brushless motors are commonly used electromechanical systems in everyday applications. Some brushless motors operate by having a controller send current signals through coils located on stationary parts called stators. When current flows through the coils, the coils cause the application of a magnetic force. Brushless motors also include a rotating part called a rotor that has magnets that interact with the magnetic forces caused by the stator windings. The controller sends current through the coils on the stator, causing a magnetic field and interaction between the stator magnetic field and the magnets on the rotor. By sending current signals through several coil windings in a particular sequence, the stator creates a rotating magnetic field that interacts with the rotor, causing the rotor to rotate and produce torque.

[0003] Brushless motors are particularly prevalent in tools such as drills and power tools. The motors are activated by a trigger on the handle of the tool and apply torque to the working end of the tool. Many of these motors are frame motors, which help prevent the motor from being damaged when the tool is dropped on the ground. Other motors are frameless, which allows the rotor and stator to move or twist relative to each other when dropped on the ground. Thus, frame motors help prevent damage, but require an end cap to maintain structural stability.

[0004] Brushless motors include a controller that includes switching elements, such as metal oxide semiconductor field effect transistors (MOSFETs), that turn on and off the current signals sent through the coils of the motor. However, the effectiveness of the controller and its MOSFETs, and the brushless motor, is limited by the heat they generate. Thus, these heat-generating components require significant cooling to work effectively, which is typically achieved in power tools by airflow from a motor fan. For reasons of space constraints, cost, simplicity, etc., some power tools place the controller and MOSFETs in the handle of the tool. However, this provides a less compact design, and makes it more difficult to cool the controller due to the airflow generated by the fan often being blocked. SUMMARY

[0005] The present invention broadly includes an end cap for a brushless motor that acts as a heat sink and dissipates heat from the controller and MOSFETs of the motor. The end cap can include fins for heat dissipation, and can be directly or thermally coupled to the controller or MOSFETs to dissipate heat through the end cap. In this way, the end cap provides a heat dissipation component with a compact design.

[0006] In particular, the present application includes a tool including a motor including a controller and a switch element. The controller controls the switch element to operate the motor in response to user input. An end cap is coupled to the motor and includes an end cap base and a fin coupled to the end cap base. The switch element is thermally coupled to the end cap.

[0007] Also disclosed is a motor including a controller to control rotation of the motor and a switch element electrically coupled to the controller. The controller is adapted to control the switch element to turn on and off in response to user input. An end cap is coupled to the motor and includes an end cap base and a fin coupled to the end cap base. The switch element is thermally coupled to the end cap. BRIEF DESCRIPTION OF DRAWINGS

[0008] For the purposes of promoting an understanding of the subject matter of the application to be protected, embodiments thereof are shown in the drawings, from an inspection of which when considered in connection with the following description, the subject matter of the application to be protected, its construction, and operation, and many of its advantages would be readily understood and appreciated.

[0009] Figure 1 is a side view of a tool in accordance with at least one embodiment of the present application.

[0010] Figure 2 is a front perspective view of internal components of a tool in accordance with at least one embodiment of the present application.

[0011] Figure 3 is a front view of an end cap in accordance with at least one embodiment of the present application.

[0012] Figure 4 is a partial side perspective cross-sectional view of an end cap in accordance with at least one embodiment of the present application taken along lines 4, 4 in Figure 3

[0013] Figure 5 is a side cross-sectional view of an end cap in accordance with at least one embodiment of the present application taken along lines 5, 5 in Figure 3 DETAILED DESCRIPTION

[0014] While the application can take many different forms, the preferred embodiments of the application are shown in the drawings and will be described in detail below. It should be understood that the present disclosure is to be considered an exemplification of the principles of the application, and is not intended to limit the broad aspects of the application to the embodiments illustrated. As used herein, the term "the present application" is not intended to limit the scope of the claimed application, but is merely used to delineate the term for discussion of the exemplary embodiments of the application.

[0015] ​​The present invention broadly includes an end cap for a brushless motor that dissipates heat from a controller and MOSFET associated with the motor. The end cap can be directly or thermally coupled to the controller and MOSFET to dissipate heat through fins in the end cap.

[0016] Figure 1 A tool 100 according to at least some embodiments of the present invention is shown. As shown, the tool 100 includes a body 105 leading to a handle 110, where the handle 110 has a trigger 112 for selectively allowing power flow from a power source 114, such as a battery or direct wall outlet connection. The trigger 112 thus causes a motor 115 to rotate and provide torque to a working end 117, such as a drill bit or screwdriver bit. For structural and heat dissipation purposes, an end cap 120 can be located at a rear end of the motor 115, which will be discussed in more detail below.

[0017] The body 105 can be any size or shape and generally includes at least some internal components necessary for the tool 100 to function. For example, the body 105 can house a gear train or electrical components that cause torque to be applied to the working end 117.

[0018] The handle 110 can be sized and shaped to be ergonomically held by a user's hand. The trigger 112 can be located at an upper portion of the handle 110 where a user's fingers would likely be located during use. The handle 110 can be devoid of controller or switch elements, such as MOSFETs, that control the motor of the tool 100.

[0019] The motor 115 can be a direct current brushless motor, although the present invention is not so limited. Thus, the motor 115 can be any electromagnetic or electromechanical motor without departing from the spirit and scope of the present invention.

[0020] As Figures 2 to 5 shown, the end cap 120 can serve as a structural component to help the motor 115 stay in place during, for example, a tool drop. The end cap 120 can also serve as a heat sink by dissipating heat from an end (rear, front, or other) of the end cap 120 to the outside of the tool 100. For example, the end cap 120 can be directly or thermally coupled to a controller and switch elements, such as MOSFETs, that drive and control the motor 115 in order to quickly dissipate heat from the most heat-affected components of the motor 115, such as a controller 130 and switch elements 135, which will be described in further detail below. The end cap 120 can be located at a rear, front, top, bottom, or side of the tool, or any other location of the tool 100.

[0021] As Figure 2As shown, motor 115 may include a drive shaft or shaft 125, which rotates and transmits torque to a gear train or other component that ultimately transmits torque to working end 117. Shaft 125 is coupled to motor 115 and serves as the output of motor 115 when motor 115 is activated.

[0022] Motor 115 may include a controller 130 coupled to switching elements 135 (such as MOSFETs and / or other types of switching elements). Controller 130 is adapted to control switching elements 135 to operate motor 115 in response to user input (such as activation or pressing of trigger 112). As shown and as understood in the art, controller 130 causes switching elements 135 to selectively turn on and off various coils within motor 115 to induce magnetic interaction between the stator and rotor of motor 115, thereby driving motor 115 and causing torque output via shaft 125. Switching elements 135 (such as MOSFETs) may be arranged, for example, in an H-bridge configuration, or in any other manner capable of operating motor 115.

[0023] like Figures 3 to 5 As shown, end cap 120 may include an end cap base and an end cap ring 140 located within a central portion of end cap 120, one or more fins 145 extending axially from end cap 120, and one or more grooves 146 between adjacent fins 145. End cap ring 140 may be located at the axial center of end cap 120 and define an end cap opening. End cap ring 140 and end cap opening receive bearings and shaft 125 of motor 115 and allow shaft 125 to extend through end cap opening. Grooves 146 allow air to flow into motor 115 for proper ventilation, and fins 145 facilitate heat dissipation from motor 115. Figure 3 As shown, the end cap 120 may also include a connecting portion 150 to allow fasteners to attach the end cap to the body 105 or the remainder of the tool 100. In some embodiments, the fasteners attach the end cap 120 to the stator of the motor 115.

[0024] Fin 145 can be a conventional fin used in conjunction with a heat dissipation structure for heat dissipation. Fin 145 can also be any other structure that increases the surface area of ​​end cap 120 and thus allows heat dissipation from controller 130 and switching element 135. For example, fin 145 can be a curved or angled structure, or otherwise shaped and sized for heat dissipation from end cap 120. In one embodiment, as shown, switching element 135 can be directly coupled to end cap 120 at fin 145.

[0025] For example, such as Figure 5As shown, the end cap 120 is directly coupled to the switch element 135, which is directly coupled to the controller 130. In this way, the end cap 120 can be more directly cooled and have better efficacy than a structure that includes other materials between the end cap 120 and the switch element 135. In other embodiments, the end cap 120 is thermally coupled to the switch element and the controller 130, meaning that the end cap 120 is coupled to the switch element and the controller 130 via a structure intended to conduct heat.

[0026] As used herein, the term "coupled" and its functional equivalents are not necessarily limited to direct, mechanical coupling of two or more members. Rather, the term "coupled" and its functional equivalents are intended to mean any direct or indirect mechanical, electrical, or chemical connection between two or more objects, features, workpieces, and / or environmental substances. In some examples, "coupled" also means that one object is integral with another object.

[0027] What is set forth in the foregoing description and accompanying drawings is provided to illustrate the present disclosure for the intended purpose. Although specific embodiments have been shown, described, and demarcated, it will be apparent to those skilled in the art that alterations and modifications can be made to this disclosure without departing from its broader aspects. The actual scope of the sought protection is therefore intended to be defined by the appended claims viewed in their proper perspective as a whole.

Claims

1. A tool comprising: a motor including a controller and a switching element, the controller controlling the switching element to operate the motor in response to user input; an end cap coupled to the motor, the end cap including: an end cap base; a plurality of fins coupled to the end cap base; and a plurality of slots, wherein each slot is disposed between two adjacent fins, extends through and across the end cap, and is adapted to allow air to flow through the end cap and into the motor, wherein the switching element is thermally coupled to the end cap.

2. The tool of claim 1, wherein, the controller is directly coupled to the switching element, and the switching element is directly coupled to the end cap.

3. The tool of claim 2, wherein, the switching element is directly coupled to the end cap at the fins.

4. The tool of claim 1, wherein, the fins extend axially from the end cap.

5. The tool of claim 1, wherein, the motor includes a shaft adapted to output torque generated by the motor.

6. The tool of claim 1, wherein, the end cap includes a connection portion for coupling the end cap to a portion of the tool.

7. The tool of claim 1, wherein the end cap includes an end cap ring located at an axial center of the end cap and defining an end cap opening.

8. A motor comprising: a controller controlling rotation of the motor; a switching element electrically coupled to the controller, the controller being adapted to control the switching element to turn on and off in response to user input; an end cap coupled to the motor, the end cap including: an end cap base; a plurality of fins coupled to the end cap base; and a plurality of slots, wherein each slot is disposed between two adjacent fins, extends through and across the end cap, and is adapted to allow air to flow through the end cap and into the motor, wherein the switching element is thermally coupled to the end cap.

9. The motor of claim 8, wherein, the controller is directly coupled to the switching element, and the switching element is directly coupled to the end cap.

10. The motor of claim 9, wherein, the switching element is directly coupled to the end cap at the fins.

11. The motor of claim 8, wherein, the fins extend axially from the end cap.

12. The motor of claim 8, wherein, the motor includes a shaft adapted to output torque generated by the motor.

13. The motor of claim 8, wherein, the end cap includes a connection portion for coupling the end cap to a portion of the tool.

14. The motor of claim 8, wherein, the end cap includes an end cap ring located at an axial center of the end cap and defining an end cap opening.

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