Heat dissipation plate, controller assembly, and power tool

Abstract

The present invention relates to a heat dissipation plate, a controller assembly, and a power tool. The heat dissipation plate comprises a substrate on which a controller is mounted. The substrate has a substrate mounting surface facing the controller, and a substrate bottom surface facing away from the controller. The substrate bottom surface is provided with a first type of undulation extending along an X axis direction, the distance by which the first type of undulation extends along the X axis direction being L, the distance between two adjacent peaks or two adjacent troughs of the first type of undulation being hL, the maximum distance between a peak and a trough of the first type of undulation in a height direction Z being τL, and a profile control function of the first type of undulation in the X axis direction being defined as follows: Z=0.5*τL*cos(2π*X / hL). The present invention, by means of designing the substrate bottom surface to have an undulating shape defined by a sine / cosine function, in one aspect, can improve heat dissipation efficiency of the heat dissipation plate, and in another aspect, can cause the heat dissipation plate to have a smaller volume and be easier to install, which can save material costs and reduce weight.

Description

Heat sink, controller assembly and power tools [Technical Field]

[0001] This invention relates to the field of power tool technology, and in particular to a heat sink, a controller assembly having the heat sink, and a power tool having the controller assembly. [Background Technology]

[0002] Power tools are instruments that use a motor to drive the working head to perform operations such as grinding, cutting, polishing, and fastening on workpieces. Currently, power tools that use lithium battery packs as energy sources and permanent magnet brushless DC motors (BLDC) as power sources generally require MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) to achieve functions such as commutation control, braking, and soft start of the motor. Therefore, the complete machine generally also needs to be equipped with a core control unit assembly (PCBA).

[0003] Taking a commonly used control unit assembly (PCBA) in the power tool industry as an example, it typically includes: filter capacitors, diodes and transistors, MOSFETs / IGBTs, a microcontroller unit (MCU), and surface-mount capacitors and resistors. These electronic components are usually packaged on a single PCB. Additionally, the PCB also has the motor's UVW three-phase wiring and the positive and negative terminals (B+ and B-) of the lithium battery pack soldered on, thus forming a complete motor and overall machine operation controller. During motor / machine operation, the MOSFETs / IGBTs continuously switch on and off at high frequency to control current, voltage, and other signals, generating heat and causing their own temperature to rise. For tools with lower voltage and lower power, the heat generated by the MOSFETs / IGBTs during operation is not significant. Generally, the PCBA is directly exposed within the overall machine structure, relying on the MOSFETs / IGBTs for natural heat dissipation through direct contact with the air, or a specific air-cooling channel structure is designed to utilize forced air cooling for effective heat dissipation.

[0004] However, as users' demands for power tool functions continue to increase, the power density of battery packs and motors is constantly increasing, and power tools are also developing towards higher voltage and higher power. The increasingly complex functions and operating conditions place higher and higher demands on the operating processing capabilities and reliability of MOSFETs / IGBTs. Currently, the heat generated by MOSFETs / IGBTs can no longer be effectively dissipated through the above methods. It is necessary to reasonably enhance heat transfer along the heat dissipation path to ensure that the junction temperature of MOSFETs / IGBTs is within their optimal operating range, so as to improve their operating reliability and service life.

[0005] Currently, for power tools with an operating voltage of 20V or higher, the PCBA is usually packaged together with the heat sink aluminum substrate and potted with glue. The heat generated by the MOSFET / IGBT is transferred to the aluminum substrate and the heat sink fins on it, and then dissipated by natural convection or forced air cooling.

[0006] For existing heat sink structures, please refer to Chinese Utility Model Patent No. 201520522736.5, published on December 30, 2015. It discloses a heat sink housing for dissipating heat from a circuit board and electrical components disposed on the circuit board. A heat dissipation structure with a concave-convex shape is provided on the outer surface of the opposite side of the heat sink housing. The heat dissipation structure is provided on the back side of the first opposite part. The heat dissipation structure is formed by providing multiple prisms at equal intervals in the front-back, left-right and right directions. In addition, multiple cutting grooves are provided at the front-back, left-right and right ends of the prisms. The heat dissipation structure is formed into a concave-convex shape by providing multiple prisms and cutting grooves. Compared with the case where the outer surface is formed into a plane, the surface area of ​​the outer surface can be increased, thereby improving the heat exchange efficiency with air and thus improving the heat dissipation effect of the heat sink housing. However, the prism not only occupies a certain height space, but also has high requirements for the installation position and direction of the column heat dissipation fins in the whole machine due to the column turbulence tail vortex effect. In addition, the heat dissipation fins can only be arranged in the direction of airflow. At the same time, the increased heat dissipation area and the height difference in space lead to a large heat dissipation temperature gradient, which increases the heat dissipation thermal resistance. These measures, to some extent, hinder the effective dissipation of heat from MOSFETs / IGBTs. [Summary of the Invention]

[0007] In view of the shortcomings of the prior art, the purpose of this invention is to provide a heat sink, controller assembly and power tool with excellent heat dissipation effect and compact structure.

[0008] The present invention solves the problems of the prior art by adopting the following technical solution: a heat sink, on which a controller is mounted, the heat sink including a base plate for mounting the controller; the base plate has a base plate mounting surface facing the controller and a base plate bottom surface facing away from the controller, the base plate bottom surface having a first type of undulation extending along the X-axis direction, the first type of undulation extending a distance L along the X-axis direction, and the distance between two adjacent peaks or two adjacent troughs of the first type of undulation being h. L The maximum distance between the crests and troughs of the first type of undulation in the height Z direction is τ. L The profile control function for the first type of undulation in the X-axis direction is defined as follows: Z = 0.5 * τ L *cos(2π*X / h L ).

[0009] A further improvement is as follows: the bottom surface of the substrate is provided with a second type of undulation extending along the Y-axis, the distance of the second type of undulation extending along the Y-axis is H, and the distance between two adjacent peaks or two adjacent troughs of the second type of undulation is h. H The maximum distance between the crests and troughs of the second type of undulation in the height Z direction is τ. H The profile control function for the second type of undulation in the Y-axis direction is defined as follows: Z = 0.5 * τ H *cos(2π*Y / h H ).

[0010] A further improvement is that the X-axis direction and the Y-axis direction are perpendicular.

[0011] A further improvement is as follows: the first type of undulation has several first cross-sections passing through the crests in the X-axis direction, and the first cross-sections are equidistant; the second type of undulation has several second cross-sections passing through the crests in the Y-axis direction, and the second cross-sections are equidistant, and h L =h H , τ L =τ H .

[0012] A further improvement is as follows: the thickness of the substrate is t, and 0.25t≤τ H ≤0.75t, and 0.25t≤τ L ≤0.75t.

[0013] A further improvement is that the thickness t of the substrate is ≤10mm.

[0014] A further improvement is to ensure that the thickness t of the substrate is ≤ 5 mm.

[0015] A further improvement is as follows: the first type of undulation has multiple h values ​​along the X-axis direction. L The first type of undulations covers the bottom surface of the substrate along the X-axis; the second type of undulations has multiple h-shaped features along the Y-axis. H Furthermore, the second type of undulations covers the bottom surface of the substrate along the Y-axis direction.

[0016] A further improvement is that the substrate mounting surface is provided with an undulating structure corresponding to the first type of undulation and / or the second type of undulation.

[0017] The present invention can also solve the problems of the prior art by adopting the following technical solution: a controller assembly, including a heat sink and a controller mounted on the heat sink, the heat sink including a base plate for mounting the controller, a sidewall extending from the periphery of the base plate, and a mounting cavity formed by the base plate and the sidewall, the controller being at least partially housed in the mounting cavity; the base plate has a base surface facing away from the controller, the base surface of the base plate is provided with undulations extending along the X-axis direction, the distance of the undulations extending along the X-axis direction is L, and the distance between two adjacent peaks or two adjacent troughs of the undulations is h. L The maximum distance between the peaks and troughs of the undulating waves in the height Z direction is τ. L The profile control function for the undulations in the X-axis direction is defined as follows: Z = 0.5 * τ L *cos(2π*X / h L ).

[0018] A further improvement is as follows: the controller includes a PCB board fixed to the substrate and electronic components disposed on the PCB board. The electronic components include at least one of the following: a switching element for supplying power to the motor assembly, a filter capacitor, a diode and a transistor, a microcontroller processing unit, and surface-mount capacitors and resistors.

[0019] A further improvement is as follows: the PCB board is provided with a threaded fastening groove, the substrate is provided with a threaded portion, the threaded fastening groove and the threaded portion are positioned correspondingly, and screws are inserted into the threaded fastening groove and the threaded portion to fix the controller to the heat sink.

[0020] A further improvement is that the substrate has a substrate mounting surface facing the controller and a boss disposed between the substrate mounting surface and the controller, the boss extending from the substrate mounting surface toward the controller.

[0021] A further improvement is that the position of the boss corresponds to the position of the switching element, and the switching element is in contact with the boss.

[0022] A further improvement is that the mounting surface of the substrate has an undulating structure corresponding to the undulation.

[0023] A further improvement is that the height of the sidewall is greater than the thickness of the PCB board, and the outer peripheral surface of the sidewall has an undulating structure corresponding to the undulation.

[0024] The present invention can also solve the problems of the prior art by adopting the following technical solution: an electric tool, including a housing, a motor assembly mounted on the housing, a switch assembly for starting and stopping the motor assembly, and a controller assembly disposed in the housing, wherein the switch assembly and the motor assembly are electrically connected to the controller assembly, the controller assembly includes a heat sink and a controller mounted on the heat sink, the heat sink being configured to transfer the heat generated by the controller to cooling air; characterized in that: the heat sink includes a base plate for mounting the controller, the surface of the base plate having undulations extending in a predetermined direction, the undulations extending in the direction of airflow of the cooling air.

[0025] A further improvement is as follows: the heat sink has a base plate bottom surface facing away from the controller, the base plate bottom surface is provided with a first type of undulation extending along the X-axis direction and a second type of undulation extending along the Y-axis direction, the X-axis direction and the Y-axis direction are perpendicular to each other.

[0026] A further improvement is as follows: the motor assembly is a brushless motor, and the power tool is powered by a battery pack; the controller includes a PCB board fixed to the substrate and electronic components disposed on the PCB board, and the three-phase wiring of the brushless motor and the positive and negative terminals of the battery pack are soldered on the PCB board.

[0027] A further improvement is as follows: the heat sink includes a base plate for mounting the controller, a side wall extending from the periphery of the base plate, and a positioning ring protruding outward from the outer periphery of the side wall, wherein the controller assembly is mounted to the housing via the positioning ring.

[0028] Compared with the prior art, the present invention has the following beneficial effects: by designing the bottom surface of the substrate into an undulating shape defined by a sine / cosine function, on the one hand, the temperature gradient difference and thermal resistance on the heat transfer path of the heat dissipation extension surface of the heat sink can be reduced, wind resistance and thermal convection greenhouse effect can be reduced, the junction temperature of the controller can be lowered, and the heat dissipation efficiency of the heat sink can be greatly improved; on the other hand, the power density of the controller can be increased. Compared with the prior art, the heat sink of the present invention is smaller in size and easier to install, which can save material costs and reduce weight. [Attached Image Description]

[0029] Figure 1 is a schematic diagram of the controller assembly of the present invention;

[0030] Figure 2 is a schematic diagram of the controller component shown in Figure 1 applied to a power tool.

[0031] Figure 3 is a structural schematic diagram of the heat sink at the first angle in the controller assembly shown in Figure 1;

[0032] Figure 4 is a structural schematic diagram of the heat sink shown in Figure 3 from the second angle;

[0033] Figure 5 is a structural schematic diagram of the heat sink shown in Figure 3 from the third angle;

[0034] Figure 6 is a structural schematic diagram of the heat sink shown in Figure 3 from the fourth angle;

[0035] Figure 7 is a cross-sectional view of the heat sink shown in Figure 6 along the AA direction;

[0036] Figure 8 is an enlarged view of circle C in the heat sink shown in Figure 7;

[0037] Figure 9 is a cross-sectional view of the heat sink in Figure 6 along the BB direction;

[0038] Figure 10 is an enlarged view of circle D in the heat sink shown in Figure 9.

Detailed Implementation Methods

[0039] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0040] The terminology used in this invention is for the purpose of describing specific embodiments only and is not intended to limit the invention. For example, terms such as "upper," "lower," "front," "rear," "left," and "right" that indicate orientation or positional relationship are based solely on the orientation or positional relationship shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device / element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0041] Please refer to Figures 1 and 2. An embodiment of the present invention relates to a controller assembly 300, and this type of controller assembly 300 is widely used in power tools 400. Further, the power tool 400 includes a housing 401, a motor assembly 402 mounted within the housing 401, a transmission assembly 403 driven by the motor assembly 402, an output head 404 connected to the end of the transmission assembly 403, a switch assembly 405 for starting / stopping the motor assembly 402, and an energy assembly 406 for providing energy to the power tool 400. The switch assembly 405 and the motor assembly 402 are simultaneously electrically connected to the controller assembly 300 located within the housing 401. The controller assembly 300 controls the rotational drive of the motor assembly 402, and the controller assembly 300 is electrically connected to the energy assembly 406, which supplies energy to the controller assembly 406.

[0042] In this embodiment, the motor assembly 402 is preferably a brushless DC motor, and the energy assembly 406 is preferably a battery pack detachably connected to the housing 401. The battery pack is installed and released relative to the housing 401 via a button located on the battery pack. Optionally, the nominal voltage of the battery pack can be greater than or equal to 10V and less than or equal to 20V; for example, the nominal voltage of the battery pack can be 12V, 18V, 20V, etc. Alternatively, the nominal voltage of the battery pack can be greater than 20V and less than or equal to 100V; for example, the nominal voltage of the battery pack can be 24V, 40V, 56V, 80V, etc.

[0043] Referring to Figures 3 and 4, the controller assembly 300 includes a heat sink 100 and a controller 200 mounted on the heat sink 100. Heat generated during the operation of the controller 200 is dissipated to the outside via the heat sink 100. Correspondingly, the motor assembly 402 includes a stator 410 mounted on a housing 401, a rotor 420 connected to the stator 410, and a fan 430 driven by the rotor. The housing 401 also has a through air inlet and outlet. The fan 430 rotates at high speed, allowing external cooling air to enter the housing 401 through the air inlet, flow sequentially through the controller assembly 300 and the motor assembly 402, and then be discharged to the outside through the air outlet. Furthermore, the heat sink 100 is configured to transfer the heat generated by the controller 200 to the cooling air. Heat transfer occurs between the controller 200 and the heat sink 100, and the cooling air flows over the outer surface of the heat sink 100, simultaneously reducing the temperature of the controller 200.

[0044] Specifically, the heat sink 100 includes a base plate 101 for mounting the controller 200 and a side wall 102 extending from the periphery of the base plate 101 along the Y-axis direction. The base plate 101 and the side wall 102 surround and form a mounting chamber 103. The side of the mounting chamber 103 away from the base plate 101 is an open side. The controller 200 is at least partially housed in the mounting chamber 103 and exposed to the open side.

[0045] The overall or cross-sectional shape of the controller assembly 300 can be cylindrical, elliptical, etc., but considering the ease of processing and molding, the controller assembly 300 used in power tools is generally rectangular or square or other irregular shapes based on the two.

[0046] In this embodiment, the heat sink 100 is made of metal to facilitate heat dissipation and cooling of the controller assembly 300; preferably, the heat sink 100 is made of aluminum.

[0047] Furthermore, the controller 200 includes a PCB board 201 fixed to the substrate 101 and electronic components 202 disposed on the PCB board 201. The electronic components 202 include switching elements for supplying power to the motor assembly 402, filter capacitors, diodes and transistors, a microcontroller unit (MCU), and surface-mount capacitors and resistors. Additionally, the PCB board 201 also has the three-phase wiring for the brushless motor (UVW) and the positive and negative terminals of the battery pack soldered on it, thus forming a complete motor assembly and overall machine operation controller. The switching elements are composed of FETs (field-effect transistors). The FETs are configured to transfer power from the battery pack to the motor assembly 402. During the operation of the motor assembly 402, the FETs continuously switch on and off at high frequency for current, voltage, and other signals, generating a large amount of heat. Therefore, the FETs are the electronic components in the controller 200 that generate the most heat. Of course, other electronic components also generate heat during operation, causing the overall temperature of the controller 200 to rise.

[0048] Referring to Figures 1 and 5, in order to facilitate the assembly of the controller 200 onto the heat sink 100, four threaded fastening slots 203 are provided at the four corners of the PCB board 201 of the controller 200, and four threaded portions 104 are also provided at the four corners of the base plate 101 of the heat sink 100. The positions of the threaded fastening slots 203 and the threaded portions 104 correspond to each other, and screws are inserted through the threaded fastening slots 203 and the threaded portions 104 to fix the controller 200 onto the heat sink 100.

[0049] In this embodiment, the heat sink 100 also includes a positioning ring 105 that protrudes outward from the outer periphery of the side wall 102. When the controller assembly 300 is installed to the housing 401 of the power tool 400 via the positioning ring 105, positioning and assembly are more convenient.

[0050] Please refer to Figures 3 and 4. The substrate 101 has a substrate mounting surface 1011 facing the controller 200, a substrate bottom surface 1012 facing away from the controller 200, and a boss 1018 disposed between the substrate mounting surface 1011 and the controller 200. The boss 1018 extends from the substrate mounting surface 1011 toward the controller 200, and the boss 1018 sets a certain distance between the substrate mounting surface 1011 and the controller 200 to facilitate the mounting of electronic components 202 on the PCB board 201. In addition, the position of the boss 1018 corresponds to the position of the switching element FET on the PCB board 201, and the switching element FET is in contact with the boss 1018 so that the heat of the switching element FET can be transferred to the substrate mounting surface 1011 and the substrate bottom surface 1012 through the boss 1018 for effective heat dissipation. The switching element FET is the component that generates the most heat among all electronic components 202. By contacting the switching element FET with the boss 1018, better heat dissipation can be achieved.

[0051] In this embodiment, the height of the sidewall 102 is greater than the thickness of the PCB board 201 housed in the heat sink 100, so that the filling resin material flows into the heat sink 100 and can be embedded in the PCB board 201 using the height of the filling resin material, thereby meeting the requirements of the power tool's "three-proof" and safety regulations.

[0052] Please refer to Figures 6 to 10. The bottom surface 1012 of the substrate is provided with a first type of undulation 110 extending along the X-axis direction. The distance of the first type of undulation 110 extending along the X-axis direction is L, and the distance between two adjacent peaks or two adjacent troughs of the first type of undulation 110 is h. L The maximum distance between the crests and troughs of the first type of undulation 110 in the height Z direction is τ. L The profile control function for the first type of undulation 110 in the X-axis direction is defined as follows: Z = 0.5 * τ L *cos(2π*X / h L ).

[0053] Since the bottom surface 1012 of the substrate faces the side with airflow, and the bottom surface 1012 of the substrate is used to transfer the heat generated by the controller 200 to the cold air and carry it out of the casing, the present invention breaks through the conventional technical solution. By designing the bottom surface 1012 of the substrate into an undulating shape defined by a sine / cosine function, on the one hand, it can reduce the temperature gradient difference and thermal resistance on the heat transfer path of the heat dissipation extension surface of the heat sink 100, reduce wind resistance and thermal convection greenhouse effect, lower the junction temperature of the controller 200, and greatly improve the heat dissipation efficiency of the heat sink 100. At the same time, it can also improve the operational reliability and service life of the power tool. On the other hand, it can increase the power density of the controller 200. Compared with the prior art, the heat sink 100 of the present invention is smaller in size and easier to install, which can save material costs and reduce weight.

[0054] Furthermore, the bottom surface 1012 of the substrate is also provided with a second type of undulation 120 extending along the Y-axis direction. The distance of the second type of undulation 120 extending along the Y-axis direction is H, and the distance between two adjacent peaks or two adjacent troughs of the second type of undulation 120 is h. H The maximum distance between the crests and troughs of the second type of undulation 120 in the height Z direction is τ. H The profile control function for the second type of undulation 120 in the Y-axis direction is defined as follows: Z = 0.5 * τ H *cos(2π*Y / h H ).

[0055] Since the first type of undulation 110 extends along the X-axis, when installing the controller assembly 300 into the housing 401 of the power tool 400, the airflow direction of the cooling air inside the housing 401 needs to be considered. Only by ensuring that the first type of undulation 110 of the controller assembly 300 extends along the airflow direction can the heat dissipation performance of the heat sink 100 be maximized. This undoubtedly brings great inconvenience to the design of the controller assembly 300. Therefore, by setting the second type of undulation 120 extending along the Y-axis on the bottom surface 1012 of the substrate, the controller assembly 300 only needs to be placed in the airflow path of the cooling air, without having to deliberately design the placement position of the controller assembly 300, which greatly reduces the design difficulty of the controller assembly 300.

[0056] Furthermore, the aforementioned first type of undulation 110 or second type of undulation 120 extends along the direction of cooling air flow.

[0057] It should be noted that the present invention utilizes sine / cosine functions to precisely define the shape of the substrate bottom surface 1012 to solve the problems existing in the prior art and achieve the desired effect of the present invention. Other function definition methods (such as arcsine, arccosine, etc.) can be considered as derived from the method defined in the present invention, and are other embodiments of the present invention, and fall within the protection scope of the present invention.

[0058] Furthermore, the above expressions are merely established by creating a suitable coordinate system to facilitate the mathematical explanation of the undulating shape characteristics described in this invention. Different function expressions can be obtained by using other coordinate systems to describe these characteristics, and all of them can be obtained through the above function transformations. These are also considered to be other embodiments of this invention and fall within the scope of protection of this invention.

[0059] Furthermore, the X-axis and Y-axis directions are perpendicular to each other to further reduce the design difficulty of the controller component 300.

[0060] In this embodiment, the outer peripheral surface of the sidewall 102 is also provided with an undulating shape similar to the first type of undulation 110 and / or the second type of undulation 120. That is, the outer peripheral surface of the sidewall 102 is provided with an undulating structure corresponding to the first type of undulation 110 and / or the second type of undulation 120.

[0061] In this embodiment, the substrate mounting surface 1011 is also provided with an undulating structure corresponding to the first type of undulation 110 and / or the second type of undulation 120. Although the filling resin material seals the substrate mounting surface 1011, making the undulating shape on the substrate mounting surface 1011 have little effect on heat dissipation, the undulating shape on the substrate mounting surface 1011 helps to ensure the uniformity of the wall thickness of the substrate 101, thereby facilitating the die casting of the substrate 101.

[0062] Please refer to Figures 8 and 10, h L and h H These represent the distances between two adjacent peaks or troughs in the X-axis and Y-axis directions, respectively, which are also the periods of the profile control function. Given that distances L and H are fixed, h... L and h H The value of determines the number of peaks and troughs of the first type of undulation 110 in the X-axis direction, and the number of peaks and troughs of the second type of undulation 120 in the Y-axis direction. Obviously, L≥h L H≥h H h L and h H This has a significant impact on improving the heat dissipation effect of the heat sink 100. Preferably, the first type of undulation 110 has multiple h-shaped features along the X-axis direction. L The second type of undulation 120 has multiple h values ​​along the Y-axis direction. H In other words, an integer number of h can be arranged along the X-axis. L That is, the distance L = n*h L (n = 1, 2, 3, ...); an integer number of h can be arranged along the Y-axis. H That is, the distance H = n * h H (n = 1, 2, 3, ...).

[0063] Furthermore, the thickness of the substrate 101 is t, and a suitable thickness can be selected according to the die-casting process of the substrate 101. However, if the thickness t is too small, the undulation shape of the first type of undulation 110 and the second type of undulation 120 in this invention is not obvious enough, and the heat dissipation effect is basically the same as that of a plane; if the thickness t is too large, the heat dissipation temperature gradient is too large, which leads to an increase in thermal resistance, which is not conducive to the heat dissipation of the controller 200. Generally, the thickness t ≤ 10 mm.

[0064] Preferably, the thickness t ≤ 5mm.

[0065] In this embodiment, τ L and τ H These represent the maximum distances between the crests and troughs in the height Z direction, which are also the amplitudes of the profile control function. Preferably, 0.25t ≤ τ. H ≤0.75t, 0.25t≤τ L ≤0.75t.

[0066] Based on the definition method of the above-mentioned profile control function and the periodicity of the sine and cosine functions, several cross-sections passing through the crests can always be obtained in the X-axis and Y-axis directions. The profiles of these cross-sections can be defined using the above method.

[0067] Furthermore, the cross-sectional spacings obtained by the above method are set to be equal, that is, the first type of undulation 110 has several first cross-sections passing through the crests in the X-axis direction, and the first cross-sections are set at equal intervals; the second type of undulation 120 has several second cross-sections passing through the crests in the Y-axis direction, and the second cross-sections are also set at equal intervals, and simultaneously satisfying h L =h H , τ L =τ H Then L / h can be obtained in the X-axis direction and the Y-axis direction respectively. L H / h H Each of the equidistant cross sections has the same control function for the profile. Therefore, the peaks and troughs of the entire bottom surface 1012 of the substrate are coplanar, and the two surfaces formed by the peaks and troughs are parallel. Thus, the heat dissipation performance of the heat sink 100 can be greatly improved.

[0068] Of course, depending on the actual heat dissipation requirements and installation needs, h can also be adjusted. L h H and τ L τ HThe mathematical relationships between key parameters such as cross-sectional spacing (e.g., increasing, decreasing, arithmetic, and geometric sequences) are used to control the undulating shape to better adapt to airflow and achieve optimal heat dissipation. Undoubtedly, this also falls under other embodiments of the present invention, employing the same technical means, solving the same problems, and achieving the same effects, and thus falls within the protection scope of the present invention.

[0069] Referring to Figures 7 and 9, the first type of undulation 110 is distributed along the X-axis direction to cover the bottom surface 1012 of the substrate, and the second type of undulation 120 is distributed along the Y-axis direction to cover the bottom surface 1012 of the substrate. That is to say, both the first type of undulation 110 and the second type of undulation 120 extend from the starting edge of the bottom surface 1012 of the substrate to the ending edge of the bottom surface 1012 of the substrate, so as to further improve the heat dissipation performance of the heat sink 100.

[0070] It should be noted that the first type of undulation 110 and the second type of undulation 120 defined in the above expression of the present invention cover the entire X-axis direction and Y-axis direction, respectively. Those skilled in the art will readily realize that the curve can also be segmented in the X-axis direction and Y-axis direction by other means to obtain other combined features, which are also considered to be other embodiments of the present invention and fall within the protection scope of the present invention.

[0071] This invention designs the bottom surface 1012 of the substrate into an undulating shape defined by a sine / cosine function. On the one hand, this reduces the temperature gradient difference and thermal resistance along the heat transfer path of the heat dissipation extension surface of the heat sink 100, reduces wind resistance and the greenhouse effect of thermal convection, lowers the junction temperature of the controller 200, and greatly improves the heat dissipation efficiency of the heat sink 100. It also improves the operational reliability and service life of the power tool. On the other hand, it increases the power density of the controller 200. Compared with existing technologies, the heat sink 100 of this invention is smaller and easier to install, saving material costs and reducing weight. By providing a second type of undulation 120 extending along the Y-axis on the bottom surface 1012 of the substrate, the controller assembly 300 only needs to be placed in the cooling airflow path, without needing to deliberately design the placement of the controller assembly 300, greatly reducing the design difficulty of the controller assembly 300.

[0072] This invention is not limited to the specific embodiments described above. Those skilled in the art will readily understand that many other alternatives exist for the heat sink, controller assembly, and power tool of this invention without departing from the principles and scope of the invention. The scope of protection of this invention is defined by the claims.

Claims

1. A heat sink, on which a controller is mounted, the heat sink comprising a base plate on which the controller is mounted; characterized in that: The substrate has a substrate mounting surface facing the controller and a substrate bottom surface facing away from the controller. The substrate bottom surface has a first type of undulation extending along the X-axis direction. The distance of the first type of undulation extending along the X-axis direction is L, and the distance between two adjacent peaks or two adjacent troughs of the first type of undulation is h. L The maximum distance between the crests and troughs of the first type of undulation in the height Z direction is τ. L The profile control function for the first type of undulation in the X-axis direction is defined as follows: Z = 0.5 * τ L *cos(2π*X / h L ).

2. The heat sink according to claim 1, characterized in that: The bottom surface of the substrate has a second type of undulation extending along the Y-axis, the distance of which the second type of undulation extends along the Y-axis is H, and the distance between two adjacent peaks or two adjacent troughs of the second type of undulation is h. H The maximum distance between the crests and troughs of the second type of undulation in the height Z direction is τ. H The profile control function for the second type of undulation in the Y-axis direction is defined as follows: Z = 0.5 * τ H *cos(2π*Y / h H ).

3. The heat sink according to claim 2, characterized in that: The X-axis direction is perpendicular to the Y-axis direction.

4. The heat sink according to claim 2, characterized in that: The first type of undulation has several first cross-sections passing through the crests in the X-axis direction, and the first cross-sections are equidistantly arranged; the second type of undulation has several second cross-sections passing through the crests in the Y-axis direction, and the second cross-sections are equidistantly arranged, and h L =h H , τ L =τ H .

5. The heat sink according to claim 2, characterized in that: The thickness of the substrate is t, where 0.25t ≤ τ. H ≤0.75t, and 0.25t≤τ L ≤0.75t.

6. The heat sink according to claim 5, characterized in that: The thickness of the substrate is t≤10mm.

7. The heat sink according to claim 6, characterized in that: The thickness of the substrate is t≤5mm.

8. The heat sink according to claim 2, characterized in that: The first type of undulation has multiple h values ​​along the X-axis direction. L The first type of undulations covers the bottom surface of the substrate along the X-axis direction; The second type of undulation has multiple h values ​​along the Y-axis direction. H Furthermore, the second type of undulations covers the bottom surface of the substrate along the Y-axis direction.

9. The heat sink according to claim 2, characterized in that: The substrate mounting surface is provided with an undulating structure corresponding to the first type of undulation and / or the second type of undulation.

10. A controller assembly comprising a heat sink and a controller mounted on the heat sink, the heat sink including a substrate for mounting the controller, a sidewall extending from the periphery of the substrate, and a mounting cavity formed by the substrate and the sidewall, the controller being at least partially housed within the mounting cavity; characterized in that: The substrate has a bottom surface facing away from the controller. The bottom surface of the substrate has undulations extending along the X-axis, the distance of which the undulations extend along the X-axis is L, and the distance between two adjacent peaks or two adjacent troughs of the undulations is h. L The maximum distance between the peaks and troughs of the undulating waves in the height Z direction is τ. L The profile control function for the undulations in the X-axis direction is defined as follows: Z = 0.5 * τ L *cos(2π*X / h L ).

11. The controller assembly according to claim 10, characterized in that: The controller includes a PCB board fixed to the substrate and electronic components disposed on the PCB board. The electronic components include at least one of the following: a switching element for supplying power to the motor assembly, a filter capacitor, a diode and a transistor, a microcontroller processing unit, and surface-mount capacitors and resistors.

12. The controller assembly according to claim 11, characterized in that: The PCB board is provided with a threaded fastening groove, and the substrate is provided with a threaded portion. The threaded fastening groove and the threaded portion are positioned correspondingly. Screws are inserted through the threaded fastening groove and the threaded portion to fix the controller to the heat sink.

13. The controller assembly according to claim 12, characterized in that: The substrate has a substrate mounting surface facing the controller and a boss disposed between the substrate mounting surface and the controller, the boss extending from the substrate mounting surface toward the controller.

14. The controller assembly according to claim 13, characterized in that: The position of the boss corresponds to the position of the switching element, and the switching element is in contact with the boss.

15. The controller assembly according to claim 13, characterized in that: The mounting surface of the substrate has an undulating structure corresponding to the undulation.

16. The controller assembly according to claim 11, characterized in that: The height of the sidewall is greater than the thickness of the PCB board, and the outer peripheral surface of the sidewall has an undulating structure corresponding to the undulation.

17. A power tool, comprising a housing, a motor assembly mounted on the housing, a switch assembly for starting and stopping the motor assembly, and a controller assembly disposed within the housing, the switch assembly and the motor assembly being electrically connected to the controller assembly, the controller assembly including a heat sink and a controller mounted on the heat sink, the heat sink being configured to transfer heat generated by the controller to cooling air; characterized in that: The heat sink includes a base plate on which the controller is mounted. The surface of the base plate has undulations extending in a predetermined direction, which extend in the direction of the cooling airflow.

18. The power tool according to claim 17, characterized in that: The heat sink has a base plate bottom surface facing away from the controller. The base plate bottom surface is provided with a first type of undulation extending along the X-axis direction and a second type of undulation extending along the Y-axis direction. The X-axis direction and the Y-axis direction are perpendicular to each other.

19. The power tool according to claim 17, characterized in that: The motor assembly is a brushless motor, and the power tool is powered by a battery pack. The controller includes a PCB board fixed to the base plate and electronic components disposed on the PCB board. The three-phase wiring of the brushless motor and the positive and negative terminals of the battery pack are soldered onto the PCB board.

20. The power tool according to claim 17, characterized in that: The heat sink includes a base plate for mounting the controller, a sidewall extending from the periphery of the base plate, and a positioning ring protruding outward from the outer periphery of the sidewall, wherein the controller assembly is mounted to the housing via the positioning ring.

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