Electric tool

Abstract

The utility model discloses an electric tool. The electric tool comprises a tool body; the at least one motor is arranged in the tool main body; the motor includes: a housing; the stator and the rotor are arranged in the shell; cooling liquid is further arranged in the shell and makes contact with the rotor. The motor further comprises at least one liquid flowing path, and the liquid flowing path comprises a liquid inlet and a liquid outlet which are opened in the inner side of the motor. By the adoption of the technical scheme, the electric tool with the good heat dissipation performance can be provided.

Description

Technical Field

[0001] This application relates to the field of tool technology, specifically to an electric tool. Background Technology

[0002] Power tools are more environmentally friendly than motor-driven tools, leading to their widespread use. Power tools generally use electric motors to drive their operation, and these motors generate heat during operation. The higher the operating current of the power tool, the more heat the motor generates, and the more severe the overheating of the motor windings. High winding temperatures can lead to decreased motor efficiency, insufficient output capacity, and other problems, causing the motor and the power tool to malfunction.

[0003] This section provides background information related to this application, which is not necessarily prior art. Utility Model Content

[0004] One object of this application is to solve or at least alleviate some or all of the aforementioned problems. Therefore, one object of this application is to provide a power tool with better heat dissipation performance.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] An electric tool includes: a tool body; at least one motor disposed within the tool body; the motor includes: a housing; a stator and a rotor disposed within the housing; a coolant is further disposed within the housing of the at least one motor, the coolant being in contact with the stator or rotor; the motor further includes: at least one liquid flow path, including an inlet and an outlet opening inside the motor.

[0007] In some embodiments, a plurality of limiting structures are formed on the inner side of the housing, and a liquid flow path is formed between adjacent limiting structures.

[0008] In some embodiments, the motor further includes a second guide disposed inside the housing and configured to form a liquid flow path.

[0009] In some embodiments, the second guide is detachably mounted to the inside of the housing.

[0010] In some embodiments, the second guide is fixedly mounted to the inside of the housing.

[0011] In some embodiments, a liquid flow path is formed on the rotor, wherein one end of the rotor forms a liquid inlet and the other end of the rotor forms a liquid outlet.

[0012] In some embodiments, a first guide is provided at the outlet, the first guide being configured to at least change the flow direction of the coolant flowing out of the outlet.

[0013] In some embodiments, the first guide is disposed on both sides of the liquid outlet.

[0014] In some embodiments, the number of first guides is greater than or equal to the number of outlets.

[0015] In some embodiments, the liquid flow path is configured as a spiral channel.

[0016] In some embodiments, the thermal conductivity of the coolant is greater than or equal to 0.1 W / (m·K) and less than or equal to 0.5 W / (m·K).

[0017] In some embodiments, the viscosity of the coolant is greater than or equal to 2 mm. 2 / s (100℃), and less than or equal to 8mm 2 / s (100℃).

[0018] In some embodiments, the volume percentage of coolant disposed within the housing is greater than or equal to 10% and less than or equal to 50%.

[0019] The advantages of this application are: by placing coolant inside the motor housing, the coolant transfers the heat generated by the motor to the housing, which then dissipates the heat to the external environment more quickly. Furthermore, the coolant flow channels within the motor allow for spray cooling, improving the motor's heat dissipation capacity and resulting in better heat dissipation performance for the power tool. Attached Figure Description

[0020] Figure 1 This is a perspective view of an embodiment of a power tool;

[0021] Figure 2 This is a perspective view of an embodiment of a motor;

[0022] Figure 3 This is a perspective view of a motor including a rotary paddle assembly according to one embodiment;

[0023] Figure 4 yes Figure 3 A top view of the motor in the image;

[0024] Figure 5 This is a perspective view of an embodiment of a motor including a rotating paddle assembly formed by protrusions;

[0025] Figure 6 This is a perspective view of a motor including a fixing portion of a rotary paddle assembly according to an embodiment;

[0026] Figure 7 This is a perspective view of a motor including a groove, according to one embodiment;

[0027] Figure 8This is a perspective view of an embodiment of an electric motor including a pump structure;

[0028] Figure 9 yes Figure 8 The motor in the image includes a side view of the pump structure;

[0029] Figure 10 yes Figure 8 The motor in the image includes a cross-sectional view of the collection assembly and the spraying assembly;

[0030] Figure 11 yes Figure 8 The motor in the image includes a top view of the spraying assembly;

[0031] Figure 12 This is a perspective view of a motor including a second guide, according to one embodiment;

[0032] Figure 13 This is a perspective view of a motor including a first guide member according to one embodiment. Detailed Implementation

[0033] Before explaining any implementation of this application in detail, it should be understood that this application is not limited to its application to the structural details and component arrangements set forth in the following description or shown in the above drawings.

[0034] In this application, the terms "comprising," "including," "having," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0035] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this application generally indicates that the preceding and following related objects have an "and / or" relationship.

[0036] In this application, the terms "connection," "combination," "coupling," and "installation" can refer to direct connection, combination, coupling, or installation, or indirect connection, combination, coupling, or installation. For example, a direct connection refers to two parts or components being connected together without the need for an intermediary, while an indirect connection refers to two parts or components each being connected to at least one intermediary, with the connection achieved through the intermediary. Furthermore, "connection" and "coupling" are not limited to physical or mechanical connections or couplings, but can also include electrical connections or couplings.

[0037] In this application, those skilled in the art will understand that relative terms (e.g., “about,” “approximately,” “basically,” etc.) used in conjunction with quantities or conditions are to include the values ​​and have the meaning indicated by the context. For example, such relative terms include at least the degree of error associated with the measurement of a particular value, tolerances associated with the particular value due to manufacturing, assembly, use, etc. Such terms should also be considered as disclosing a range defined by the absolute values ​​of the two endpoints. Relative terms may refer to a certain percentage (e.g., 1%, 5%, 10% or more) of the indicated value. Numerical values ​​not using relative terms should also be disclosed as specific values ​​with tolerances. Furthermore, “basically” when expressing relative angular relationships (e.g., substantially parallel, substantially perpendicular) may refer to a certain degree (e.g., 1 degree, 5 degrees, 10 degrees or more) added to or subtracted from the indicated angle.

[0038] In this application, those skilled in the art will understand that the function performed by a component can be performed by one component, multiple components, one part, or multiple parts. Similarly, the function performed by a part can also be performed by one part, one component, or a combination of multiple parts.

[0039] In this application, the directional terms "upper," "lower," "left," "right," "front," and "rear" are used to describe the orientation and positional relationships shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should be understood that when an element is mentioned as being connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected through an intermediate element. It should also be understood that directional terms such as upper side, lower side, left side, right side, front side, and rear side not only represent positive orientation but can also be understood as lateral orientation. For example, "below" can include directly below, lower left, lower right, lower front, and lower rear.

[0040] The power tools applicable to the technical solutions of this application include outdoor walking equipment, handheld power tools, fastening power tools, cutting power tools, grinding power tools, etc. Examples include ride-on lawnmowers, hair dryers, electric drills, circular saws, reciprocating saws, impact wrenches, impact screwdrivers, and hammer drills. Other types of power tools that adopt the substantive content of the disclosed technical solutions will fall within the protection scope of this application.

[0041] like Figure 1 As shown, the power tool disclosed in this application is an outdoor walking device 100, which is a ride-on lawnmower that allows users to sit or stand on it to operate for mowing lawns and other vegetation. The outdoor walking device 100 includes: a housing assembly, an energy storage device, a walking assembly, and a frame. The frame extends substantially in a front-to-back direction and, together with the housing assembly, constitutes the main body of the outdoor walking device. The energy storage device provides energy to the mowing assembly and the walking assembly, enabling the outdoor walking device to be used as a power tool.

[0042] The walking assembly includes a set of walking wheels and a walking motor. The walking wheels are connected to the main unit to support it. The walking wheels can drive the outdoor walking device to move in at least the forward and backward direction. The walking assembly includes a rear walking wheel and a front walking wheel. The walking motor drives the rear walking wheel or the front walking wheel to rotate, enabling the outdoor walking device 100 to move on the ground. The outdoor walking device 100 also includes functional components for realizing tool functions and a drive motor for driving the functional components. In this embodiment, the outdoor walking device 100 is a ride-on lawnmower, and the functional component is specifically a lawnmower assembly, which includes a mowing element for cutting lawn grass, and the drive motor drives the mowing element to rotate. The structure and position of the above-mentioned mowing component and drive motor are conventional settings in the art, and will not be described in detail in this application. The outdoor walking device 100 is internally equipped with a motor 200 (not shown in the figure), which can be either a walking motor or a drive motor, or a combination of both. The motor 200 can be either an internal rotor motor or an external rotor motor, and this application does not limit this.

[0043] This application uses motor 200 as an example of an external rotor motor for specific explanation. Figure 2As shown, the motor 200 includes a housing 210, an output shaft 220, a stator 230, and a rotor 240. An installation space is formed within the housing 210. Both the stator 230 and the rotor 240 are installed within this space, with the stator 230 located inside the rotor 240. The output shaft 220 is located within the installation space, and its output end protrudes from both the stator 230 and the rotor 240. The stator 230 is a fixed component inside the housing 210, and its main function is to generate a rotating magnetic field. The rotor 240 is capable of rotation, and its main function is to be cut by magnetic lines of force in the rotating magnetic field, thereby generating an electric current. For ease of description, the following definitions are used: Figure 2 As shown: top and bottom.

[0044] like Figure 2 As shown, a coolant 300 can be installed inside the housing 210. The heat generated when the motor 200 operates can be conducted to the housing 210 through the coolant 300. The coolant 300 is in contact with both the housing 210 and the stator 230 or rotor 240. Specifically, when the motor 200 operates, the heat generated on the motor 200 windings is transferred through the stator 230 or rotor 240 to the coolant 300, and then to the housing 210. Figure 2 As shown, in this application, the coolant 300 is specifically in contact with the housing 210 and the rotor 240. The coolant 300 transfers the heat generated by the motor 200 windings to the housing 210, avoiding the low efficiency of heat transfer via air and the difficulty in quickly dissipating heat during prolonged motor operation. Therefore, the housing 210 can quickly dissipate the heat generated by the motor 200 windings to the external environment, improving the heat dissipation capacity of the motor 200 and resulting in better heat dissipation performance of the outdoor walking device 100.

[0045] In some embodiments, the power of the motor 200 is greater than or equal to 2kW and less than or equal to 10kW. Optionally, the power of the motor 200 is 3.5kW. Optionally, the power of the motor 200 is 5kW. The power of the motor 200 is 6.5kW. The power of the motor 200 is 8kW.

[0046] In some embodiments, the rotational speed of motor 200 is greater than or equal to 2000 RPM and less than or equal to 7000 RPM. In some embodiments, the rotational speed of motor 200 is greater than or equal to 2000 RPM and less than or equal to 6000 RPM. In some embodiments, the rotational speed of motor 200 is greater than or equal to 2000 RPM and less than or equal to 5000 RPM. In some embodiments, the rotational speed of motor 200 is greater than or equal to 3000 RPM and less than or equal to 7000 RPM. In some embodiments, the rotational speed of motor 200 is greater than or equal to 3000 RPM and less than or equal to 6000 RPM. In some embodiments, the rotational speed of motor 200 is greater than or equal to 3000 RPM and less than or equal to 5000 RPM. In some embodiments, the rotational speed of motor 200 is greater than or equal to 4000 RPM and less than or equal to 7000 RPM.

[0047] Optionally, the speed of motor 200 is 2400 RPM. Optionally, the speed of motor 200 is 3000 RPM.

[0048] Optionally, the speed of motor 200 is 3500 RPM. Optionally, the speed of motor 200 is 4000 RPM.

[0049] Optionally, the speed of motor 200 is 4600 RPM. Optionally, the speed of motor 200 is 5000 RPM.

[0050] Optionally, the speed of motor 200 is 5800 RPM. Optionally, the speed of motor 200 is 6300 RPM.

[0051] In some embodiments, the thermal conductivity of the coolant 300 is greater than or equal to 0.1 W / (m·K) and less than or equal to 0.5 W / (m·K). Optionally, the thermal conductivity of the coolant 300 is 0.2 W / (m·K). Optionally, the thermal conductivity of the coolant 300 is 0.3 W / (m·K).

[0052] In some embodiments, the viscosity of the coolant 300 is greater than or equal to 2 mm. 2 / s (100℃), and less than or equal to 8mm 2 / s (100℃). Optionally, the viscosity of coolant 300 is 3mm. 2 / s (100℃). Optionally, the viscosity of coolant 300 is 4.2 mm. 2 / s (100℃). Optionally, the viscosity of coolant 300 is 5.5 mm. 2 / s (100℃). Optionally, the viscosity of coolant 300 is 7.6 mm. 2 / s (100℃).

[0053] In some embodiments, the volume percentage of coolant 300 disposed within the housing 210 is greater than or equal to 10% and less than or equal to 50%. Specifically, the volume percentage of coolant 300 within the housing 210 refers to the amount of coolant 300 disposed within the housing 210 relative to the total internal space of the housing 210; that is, the ratio of the volume of coolant 300 to the volume of the internal space of the housing 210. Optionally, the volume percentage of coolant 300 disposed within the housing 210 is 15%. Optionally, the volume percentage of coolant 300 disposed within the housing 210 is 20%. Optionally, the volume percentage of coolant 300 disposed within the housing 210 is 30%. Optionally, the volume percentage of coolant 300 disposed within the housing 210 is 45%.

[0054] By setting the thermal conductivity coefficient, viscosity, and volume ratio of the coolant 300 within the housing 210, the coolant 300 can effectively cool the motor 200, thereby improving the heat dissipation performance of the motor 200 and the outdoor walking device 100.

[0055] Optionally, coolant 300 can be vegetable oil. Optionally, coolant 300 can be mineral oil. Optionally, coolant 300 can be synthetic oil. Optionally, coolant 300 can also be any other medium that meets the above-mentioned conditions for coolant 300. Optionally, coolant 300 can be composed of one or more media, and this application does not limit it.

[0056] In some embodiments, the motor 200 further includes a vortex blocker 400 disposed within the housing 210. The vortex blocker 400 includes at least a blocking portion 410 that blocks the rotation of the coolant 300. When the motor 200 is operating, the coolant 300 within the housing 210 rotates at high speed under the drive of the rotor 240, forming vortices. This causes the coolant surface near the housing 210 to rise, while the surface near the output shaft 220 to sink. Consequently, the contact area between the coolant 300 and the motor 200 windings is reduced, decreasing the heat transfer effect of the coolant 300 in transferring heat generated by the motor 200 windings to the housing 210. By providing the vortex blocker 400, the probability of the coolant 300 forming vortices under the drive of the rotor 240 can be reduced, or the formation of vortices in the coolant 300 under the drive of the rotor 240 can be prevented, thereby improving the heat transfer effect of the coolant 300.

[0057] In some embodiments, the number of multiple blocking portions 410 may be four. In some embodiments, the number of multiple blocking portions 410 may be five. In some embodiments, the number of multiple blocking portions 410 may be six. In some embodiments, the number of multiple blocking portions 410 may be ten. In some embodiments, the number of multiple blocking portions 410 may be any number greater than one.

[0058] In some embodiments, a plurality of blocking portions 410 are formed protruding inward on the inner side of the housing 210. The blocking portions 410 are fixedly installed on the inner side of the housing 210 and are integrally formed with the housing 210. Figure 3 and Figure 4 As shown, optionally, the blocking portion 410 protruding inward from the inner side of the housing 210 includes any one or a combination of blocking portions 410 formed by ribs on the inner sidewall of the housing 210 and blocking portions 410 formed by ribs on the inner bottom of the housing 210. The plurality of blocking portions 410 can be as follows: Figure 3 and Figure 4 The obstructions 410, which are fixedly installed at equal intervals on the inner sidewalls and bottom of the housing 210 as shown, can also be fixedly installed at non-fixed intervals on the inner sidewalls and bottom of the housing 210; this application does not limit this. The multiple obstructions 410 fixedly installed inside the housing 210 extend in a direction substantially parallel to the output shaft 220 of the motor 200 within the housing 210. Optionally, the obstructions 410 formed by the ribs can be as follows: Figure 3 and Figure 4 The cuboid shown can also be any other shape that can serve as a barrier; this application does not limit it.

[0059] In some embodiments, such as Figure 5 As shown, the blocking portion 410 formed by the inward protrusion of the inner sidewall of the housing 210 includes a portion formed by the inward protrusion of the inner sidewall of the housing 210, and the blocking portion 410 is constituted by the protruding features of the inner sidewall of the housing 210. Optionally, the protruding features of the inner sidewall of the housing 210 can be formed at equal intervals. Optionally, the protruding features of the inner sidewall of the housing 210 can also be formed at irregular intervals. Optionally, in the vertical direction of the motor 200, the width of the protruding features of the inner sidewall of the housing 210 can remain constant. Optionally, in the vertical direction of the motor 200, the width of the protruding features of the inner sidewall of the housing 210 can gradually widen from top to bottom. Optionally, in the vertical direction of the motor 200, the width of the protruding features of the inner sidewall of the housing 210 can gradually narrow from top to bottom. Optionally, in the vertical direction of the motor 200, the width of the protruding features of the inner sidewall of the housing 210 can vary randomly, and this application does not limit it. The protruding feature on the inner sidewall of the housing 210 extends in a direction that is substantially parallel to the output shaft 220 of the motor 200.

[0060] In some embodiments, the rotary stop assembly 400 can be detachably mounted to the inside of the housing 210, and the rotary stop assembly 400 and the housing 210 are formed separately. The rotary stop assembly 400 includes both a blocking portion 410 and a fixing portion 420, which is used to fix the rotary stop assembly 400 to the inside of the housing 210. In some embodiments, the fixing portion 420 and the blocking portion 410 can be integrally formed. Figure 6 As shown, the fixing part 420 can be arranged around the inner side of the housing 210 and fixedly installed on the housing 210. Optionally, the fixing part 420 can be fixedly installed on the housing 210 by screws. Optionally, the fixing part 420 can be press-fitted onto the housing 210 by the motor 200. Optionally, the blocking part 410 can be directly installed on the housing 210 based on the fixing part 420. Optionally, as... Figure 7 As shown, a groove 211 is formed on the inner sidewall and / or bottom of the housing 210 to mate with the blocking part 410, which, together with the fixing part 420, mounts the blocking part 410 onto the housing 210. Figure 6 As shown, the blocking portion 410 includes ribs installed on the inner sidewall of the housing 210 to form the blocking portion 410. Multiple blocking portions 410 can be connected to the fixing portion 420 at equal intervals or at irregular intervals. The extending direction of the multiple blocking portions 410 within the housing 210 is substantially parallel to the output shaft 220 of the motor 200.

[0061] In some embodiments, the fixing part 420 and the blocking part 410 are separately provided. A groove 211 is formed on the inner sidewall and / or bottom of the housing 210 to mate with the blocking part 410, and the blocking part 410 is inserted into the groove 211 for initial fixation. A fixing part 420 is then provided around the inner side of the housing 210, abutting against the upper part of the blocking part 410, and together with the groove 211, to complete the fixation of the blocking part 410. The fixing part 420 can be fixed to the housing 210 by screws, or it can be press-fitted to the housing 210 by the motor 200.

[0062] In some embodiments, the motor 200 further includes a pump structure 500 for pumping coolant 300 from a first end of the motor 200 to a second end of the motor 200 to dissipate heat from the motor 200. Specifically, the pump structure 500 includes a suction assembly 510 for pumping coolant 300 from the bottom end of the motor 200 to the top end of the motor 200 to dissipate heat from the windings and other structures of the motor 200. Optionally, the suction assembly 510 can be a suction pipe. Figure 8As shown, the pump structure 500 pumps coolant 300 from the lower end of the motor 200 to the upper end of the motor 200. Optionally, the pump structure 500 can be driven by the motor 200 itself. Optionally, the pump structure 500 can also be driven by a motor other than the motor 200 in the outdoor walking device 100. Optionally, an additional motor can be added to the outdoor walking device 100 to drive the pump structure 500.

[0063] like Figure 8 As shown, the pump structure 500 also includes a liquid outlet assembly 520, and the motor 200 includes a collection assembly 530 and a spraying assembly 540. Both the collection assembly 530 and the spraying assembly 540 are disposed within the mounting space formed by the housing 210. The liquid outlet assembly 520 is used to discharge the coolant 300 pumped from the suction assembly 510 to the second end of the motor 200. The collection assembly 530 is used to collect the coolant 300 flowing out of the liquid outlet assembly 520. The spraying assembly 540 is fixed to the retainer of the motor 200 and cooperates with the collection assembly 530 to receive the coolant 300 from the collection assembly 530. Optionally, the collection assembly 530 can be an annular structure to match the structure of the motor 200. Optionally, the spraying assembly 540 can be an annular structure to match the structures of the collection assembly 530 and the motor 200.

[0064] like Figure 9 As shown, the collecting assembly 530 is disposed below the liquid outlet assembly 520. The collecting assembly 530 consists of a base plate 531 and a side wall 532, and is used to restrict the flow direction and flow position of the coolant 300 flowing out of the liquid outlet assembly 530. Optionally, as shown... Figure 10 As shown, the base plate 531 of the collection assembly 530 includes a first limiting structure 533 that is recessed downward around the perimeter, so that the coolant 300 can be confined within the first limiting structure 533 after flowing into the collection assembly 530. Figure 8 and Figure 10 As shown, the collecting assembly 530 includes at least one hole 534 for downward flow of coolant 300. At least one hole 534 is provided on the first limiting structure 533 for downward flow of coolant 300.

[0065] like Figure 9 and Figure 10As shown, the spraying assembly 540 is disposed below the collecting assembly 530. The spraying assembly 540 includes a top plate 541 and a second limiting structure 542, which is a downwardly recessed structure disposed around the circumference of the spraying assembly 540. In the vertical direction of the motor 200, the second limiting structure 542 is located below the top plate 541. The top plate 541 is used to receive coolant 300 flowing out from the holes 534 of the collecting assembly 530, and the second limiting structure 542 is used to receive coolant 300 from the top plate 541. The spraying assembly 540 includes at least one spray hole 543 for spraying coolant 300 onto the motor 200. Wherein, as... Figure 11 As shown, the spray hole 543 is provided on the second limiting structure 542 for the coolant 300 to flow downwards, so that the coolant 300 can flow to the winding of the motor 200.

[0066] Optionally, to facilitate the cooperation between the spraying assembly 540 and the collecting assembly 530, the annular diameter of the spraying assembly 540 and the annular diameter of the collecting assembly 530 can be the same. Optionally, in the vertical direction of the motor 200, the second limiting structure 542 corresponds to the first limiting structure 533, and the second limiting structure 542 and the first limiting structure 533 pass through the same circumference along the vertical direction of the motor 200. Optionally, the circumference traversed by the second limiting structure 542 along the vertical direction of the motor 200 is larger than the circumference traversed by the first limiting structure 533 along the vertical direction of the motor 200, that is, the second limiting structure 542 is closer to the housing 210 than the first limiting structure 533, and the first limiting structure 533 is closer to the output shaft 220 of the motor 200 than the second limiting structure 542.

[0067] In some embodiments, the motor 200 includes at least one liquid flow path 600, which includes an inlet 610 and an outlet 620 opening inside the motor 200. Optionally, the inlet 610 is located on the lower inner side of the motor 200, and the outlet 620 is located on the upper inner side of the motor 200. Optionally, the liquid flow path 600 is a spiral channel.

[0068] In some embodiments, a plurality of limiting structures (i.e., third limiting structures) are formed inside the housing 210 of the motor 200, and a liquid flow path 600 is formed between adjacent limiting structures. The housing 210 of the motor 200 also has a plurality of third limiting structures protruding outwards, and these third limiting structures are integrally formed with the housing. In the vertical direction of the motor 200, the third limiting structures are spiral-shaped. The motor 200 also includes a fourth limiting structure that cooperates with the third limiting structures, and the fourth limiting structure is disposed on the upper part of the inner side of the housing 210. When the motor 200 is running, the liquid flow path 600 formed by the third limiting structure guides the coolant 300 from the lower inlet 610 to the upper outlet 620. Then, the fourth limiting structure restricts the coolant 300 at the outlet 620, causing the coolant 300 to fall back from the top of the motor 200 and spray the windings of the motor 200, further improving the heat dissipation effect of the coolant 300 on the windings of the motor 200.

[0069] In some embodiments, the motor 200 includes a second guide 700 disposed inside the housing 210 to form a liquid flow path 600. Optionally, the second guide 700 is detachably mounted to the inside of the housing 210. Optionally, the second guide 700 is fixedly mounted to the inside of the housing 210. Figure 12 As shown, the second guide 700 includes a first guide portion 710 disposed inside the housing 210 and a second guide portion 720 disposed on the upper part of the inner side of the housing 210. The first guide portion 710 and the second guide portion 720 are integrally formed. The first guide portion 710 is helical in shape, forming a liquid flow path 600 with a helical channel between adjacent first guide portions 710. Optionally, the number of first guide portions 710 can be any number greater than 1. The second guide portion 720 is used to guide the coolant 300 to the upper part of the motor 200 via the liquid flow path 600 to the windings of the motor 200. Optionally, the second guide 700 is also mounted to the inner side of the housing 210 via the second guide portion 720. The second guide portion 720 can be mounted to the inner side of the housing 210 by screws. When the motor 200 is running, the liquid flow path 600 formed by the first guide part 710 guides the coolant 300, guiding the coolant 300 from the lower inlet 610 to the upper outlet 620. Then, the second guide part 720 guides the coolant 300 at the outlet 620, causing the coolant 300 to fall back from the top of the motor 200 and spray the windings of the motor 200.

[0070] In some embodiments, a liquid flow path 600 is formed on the rotor 240, wherein an inlet 610 of the liquid flow path 600 is formed at one end of the rotor 240, and an outlet 620 of the liquid flow path 600 is formed at the other end of the rotor 240. For example... Figure 13 As shown, a liquid inlet 610 is formed at the lower end of the rotor 240, and a liquid outlet 620 is formed at the upper end of the rotor 240. Thus, when the rotor 240 rotates, coolant 300 flows in from the lower liquid inlet 610 and flows out through the liquid flow path 600 to the upper liquid outlet 620. The number of liquid flow paths 600 can be any number greater than one, and this application does not limit it.

[0071] The motor 200 also includes a first guide 800, which is disposed at the outlet 620 and can at least change the flow direction of the coolant 300 flowing out of the outlet 620. Specifically, the first guide 800 guides the coolant 300 flowing out of the outlet 620 onto the windings of the motor 200, causing the coolant 300 to fall back from the top of the motor 200 and spray onto the windings. Optionally, the first guide 800 can be as follows: Figure 13 The shape of the guide plate is shown. Optionally, the first guide 800 can also be any other shape capable of guiding, which is not limited in this application. Optionally, the first guide 800 can be fixed to the housing 210, specifically fixed to the upper side of the housing 210. Optionally, the number of first guides 800 is greater than or equal to the number of outlets 620, so as to guide the coolant 300 flowing out of the outlets 620. Optionally, the first guides 800 can be arranged on both sides of the outlets 620, so that the coolant 300 can be guided whether it flows to the left or right after flowing out of the outlets 620.

[0072] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that the above embodiments do not limit this application in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of this application.

Claims

1. An electric power tool, comprising: a tool body; at least one motor arranged in the tool body; the motor comprising: a housing; a stator and a rotor arranged in the housing; a cooling liquid arranged in the housing and in contact with the rotor; characterized in that the motor further comprises: at least one liquid flow path comprising an inlet and an outlet opening in the motor.

2. The power tool of claim 1, wherein, a plurality of limiting structures are formed in the housing, and the liquid flow path is formed between adjacent limiting structures.

3. The power tool of claim 1, wherein the motor further comprises a second guide arranged in the housing and forming the liquid flow path.

4. The power tool of claim 3, wherein, the second guide is detachably mounted to the housing.

5. The power tool of claim 3, wherein, the second guide is fixedly mounted to the housing.

6. The power tool of claim 1, wherein, the liquid flow path is formed on the rotor, wherein one end of the rotor forms the inlet and the other end of the rotor forms the outlet.

7. The power tool as described in claim 6, characterized in that, a first guide is arranged at the outlet and arranged to change the flow direction of the cooling liquid flowing out of the outlet.

8. The power tool of claim 7, wherein, the first guide is arranged on both sides of the outlet.

9. The power tool of claim 7, wherein the first and second electrical conductors are electrically connected to the motor by a common electrical connector. the number of the first guide is greater than or equal to the number of the outlet.

10. The power tool of claim 1, wherein, the liquid flow path is arranged as a spiral channel.

11. The power tool of claim 1, wherein, the thermal conductivity of the cooling liquid is greater than or equal to 0.1 W / (m·K) and less than or equal to 0.5 W / (m·K).

12. The power tool of claim 1, wherein, The viscosity of the coolant is greater than or equal to 2 mm 2 / s (100°C) and less than or equal to 8 mm 2 / s (100°C).

13. The power tool of claim 1, wherein, the volume ratio of the cooling liquid arranged in the housing is greater than or equal to 10% and less than or equal to 50%.

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