Circular saw

Abstract

The invention discloses a circular saw which comprises a first motor comprising a first driving shaft rotating around a first axis; a second motor; comprising a second drive shaft rotating about a second axis; the second driving shaft and the first driving shaft are coaxially arranged; the first motor and the second motor are mechanically coupled; the motor diameter of the first motor is smaller than or equal to 70 mm, and the motor diameter of the second motor is smaller than or equal to 70 mm. The power transmission mechanism transmits power of at least one of the first motor and the second motor to the output shaft; the power transmission mechanism comprises a transmission assembly, and the transmission assembly at least comprises a speed reducing mechanism. The bottom plate is movably connected with the main machine shell, and a bottom plate bottom face making contact with a workpiece is formed on the bottom plate. The electric tool is driven by the two motors in a matched mode, and the motor size layout is more reasonable.

Description

Technical Field

[0001] The present application relates to an electric tool, in particular to a circular saw. Background Art

[0002] When the power tools in the related art are working, the output mechanism usually needs to be able to work under both light-load and heavy-load conditions. In order to enable the power tool to output a large torque to adapt to heavy-load conditions, a motor with large power and output torque is usually set in the power tool. The high-power motor can drive the output mechanism to carry a large load. However, when the power tool is in a light-load condition, the power consumption of the high-power motor will be relatively large, resulting in serious waste. As a result, the working state of the motor is reduced when the load is light, affecting the use time of the power tool.

[0003] This section provides background information related to the present application which is not necessarily prior art. Summary of the invention

[0004] One object of the present application is to solve or at least alleviate part or all of the above problems. To this end, one object of the present application is to provide a circular saw that uses two motors with more reasonable sizes and arrangement positions to cooperate with the drive output shaft to output work.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions: A circular saw comprises an output shaft for mounting a cutting piece; the cutting piece rotates around the output axis; a first motor comprises a first drive shaft rotating around the first axis; a second motor comprises a second drive shaft rotating around the second axis; the second drive shaft is coaxially arranged with the first drive shaft; the first motor and the second motor are mechanically coupled; the motor diameter of the first motor is less than or equal to 70 mm, and the motor diameter of the second motor is less than or equal to 70 mm; a power transmission mechanism transmits power of at least one of the first motor and the second motor to the output shaft; the power transmission mechanism comprises a transmission assembly, and the transmission assembly at least comprises a reduction mechanism; a power supply comprises at least one battery pack for providing an energy source to the motor; a main body housing at least partially accommodates the first motor, the second motor and the power transmission mechanism; the main body housing comprises a first housing, and the first housing is formed or connected with a gripping portion for grasping; a bottom plate is movably connected to the main body housing, and the bottom plate is formed with a bottom surface of the bottom plate in contact with the workpiece.

[0006] In some embodiments, the first motor is an outer rotor motor, and the second motor is an outer rotor motor.

[0007] In some embodiments, the first drive shaft rotates synchronously with the second drive shaft.

[0008] In some embodiments, the first motor includes a first stator and a first rotor, and the first drive shaft is formed or connected to the first rotor; the second motor includes a second stator and a second rotor; and the second drive shaft is formed or connected to the second rotor.

[0009] In some embodiments, a motor fixing portion is further included, and the motor fixing portion is connected to the first stator and the second stator respectively.

[0010] In some embodiments, the motor fixing portion is provided with a receiving channel, and the receiving channel is used to receive at least a portion of the first driving shaft and the second driving shaft.

[0011] In some embodiments, the receiving channel at least partially overlaps with the first stator along the first axis direction, and the receiving channel at least partially overlaps with the second stator along the first axis direction.

[0012] In some embodiments, the output shaft is not coaxially disposed with the first drive shaft.

[0013] In some embodiments, along the direction of the output axis, the projection of the first axis and the projection of the second axis are located above the projection of the output axis.

[0014] In some embodiments, it is characterized in that, in a direction perpendicular to the bottom surface of the base plate, the projection of the first drive axis and the projection of the second drive axis have two endpoints that are farthest apart in the direction of the output axis, and a width interval W is defined between two straight lines on the projection plane that pass through one endpoint respectively and are perpendicular to the output axis, and the projection of the center of gravity of the circular saw is set within the width interval W.

[0015] The beneficial effects of the present application are: the circular saw of the present application also includes: a first motor, including a first drive shaft rotating around a first axis; a second motor; including a second drive shaft rotating around a second axis; the second drive shaft is coaxially arranged with the first drive shaft; the first motor and the second motor are mechanically coupled; the motor diameter of the first motor is less than or equal to 70 mm, and the motor diameter of the second motor is less than or equal to 70 mm; a power transmission mechanism, transmitting power of at least one of the first motor and the second motor to the output shaft; the power transmission mechanism includes a transmission assembly, and the transmission assembly includes at least a reduction mechanism; two motors are used to work together to output the torque of the motor assembly through the output shaft, and the end points of the torque transmission paths of the multiple motors are the same, which improves the high-efficiency working range of the electric tool as a whole, realizes a motor diameter of less than or equal to 70 mm, or even smaller, and realizes the application of small motors in circular saw products. At the same time, the two axially arranged small-diameter motors make the size of the whole machine more compact. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a three-dimensional structural diagram of a circular saw in one embodiment of the present application; Figure 2is a structural diagram of a circular saw in one embodiment of the present application in a first state; Figure 3 is a structural diagram of a circular saw in an embodiment of the present application in a second state; Figure 4 is a structural diagram of a circular saw according to an embodiment of the present application from another perspective, wherein relevant components of a motor assembly are shown; Figure 5 It is a partial component structure diagram of a circular saw of an embodiment of the present application from a third perspective, with the cutting piece-related components removed; Figure 6 yes Figure 5 Partial view of the AA section view in; Figure 7 is an exploded view of some components of a circular saw according to an embodiment of the present application; Figure 8 is a half-section view of a motor assembly and a receiving housing of a circular saw according to an embodiment of the present application; Fig. 9 is a three-dimensional structural diagram of another example of a circular saw in one embodiment of the present application; Fig.10 is a three-dimensional structural diagram of a third example of a circular saw in an embodiment of the present application; Fig.11 is a cross-sectional view of a first motor in the motor assembly of the present application; Fig.12 is a schematic diagram of the internal structure of a circular saw according to an embodiment of the present application; Fig.13 is a schematic diagram of a partial structure of a circular saw in an embodiment of the present application; Fig.14 yes Fig.13 A partial cross-sectional view of the structure; Fig.15 is with Fig.12 A structural diagram of another example with a different structure; Fig.16 is with Fig.12 A schematic diagram of the structure of a third example with a different structure; Fig.17 is with Fig.12 A schematic diagram of the structure of a fourth example with a different structure; Fig.18 is with Fig.12 Schematic diagram of the structure of the fifth example with different structure Fig.19 is a schematic diagram of the structure of a power transmission mechanism of a circular saw in one embodiment of the present application; Fig. 20 yes Fig.19 A structural diagram from another perspective; Fig.21 yes Fig. 20 A schematic diagram of a partial cross-sectional view from another perspective; Fig. 22 yes Fig. 20 A structural diagram from another perspective; Fig.23 is a schematic diagram of the structure of a second power transmission mechanism of a circular saw in one embodiment of the present application; Fig.24 is a schematic diagram of the structure of a third power transmission mechanism of a circular saw in an embodiment of the present application; Fig.25 is a schematic diagram of the structure of a fourth motor assembly, a power transmission mechanism and a receiving shell of a circular saw in an embodiment of the present application; Fig.26 yes Fig.25 A schematic diagram of the structure of the motor assembly and the power transmission mechanism from another perspective; Fig. 27 is a schematic diagram of an electrical structure diagram of an embodiment of the present application; Fig.28 is a schematic diagram of another electrical structure diagram of an embodiment of the present application; Fig.29 is a control flow chart of an embodiment of the present application; Fig.30 It is another control flow chart of an embodiment of the present application. DETAILED DESCRIPTION

[0017] Before any embodiments of the application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the above drawings.

[0018] In this application, the terms "comprises", "includes", "has" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device that includes the element.

[0019] In this application, the term "and / or" is a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects before and after are in an "and / or" relationship.

[0020] In the present application, the terms "connect", "combine", "couple", and "install" may refer to direct connection, combination, coupling, or installation, or indirect connection, combination, coupling, or installation. For example, direct connection refers to two parts or components being connected together without the need for an intermediate piece, and indirect connection refers to two parts or components being connected to at least one intermediate piece respectively, and the two parts or components being connected via the intermediate piece. In addition, "connect" and "couple" are not limited to physical or mechanical connections or couplings, and may include electrical connections or couplings.

[0021] In this application, it will be understood by those of ordinary skill in the art that relative terms (e.g., "about," "approximately," "substantially," etc.) used in conjunction with quantities or conditions include the values ​​and have the meaning indicated by the context. For example, the relative terms include at least the degree of error associated with the measurement of a specific value, the tolerances caused by manufacturing, assembly, and use associated with a specific value, etc. Such terms should also be considered to disclose a range defined by the absolute values ​​of the two endpoints. Relative terms may refer to plus or minus a certain percentage (e.g., 1%, 5%, 10% or more) of the indicated value. Numerical values ​​that do not use relative terms should also be disclosed as specific values ​​with tolerances. In addition, "substantially" may refer to plus or minus a certain degree (e.g., 1 degree, 5 degrees, 10 degrees or more) on the basis of the indicated angle when expressing a relative angular position relationship (e.g., substantially parallel, substantially perpendicular).

[0022] In this application, it will be understood by those skilled in the art 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.

[0023] In the present application, the terms "upper", "lower", "left", "right", "front", "back" and other directional words are described based on the orientation and positional relationship shown in the accompanying drawings, and should not be understood as limiting the embodiments of the present application. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another element "upper" or "lower" through an intermediate element. It should also be understood that directional words such as upper side, lower side, left side, right side, front side, back side, etc. not only represent the positive orientation, but can also be understood as the lateral orientation. For example, the bottom can include directly below, lower left, lower right, lower front, and lower back, etc.

[0024] In this application, the terms "controller", "processor", "central processing unit", "CPU", and "MCU" are interchangeable. When a unit "controller", "processor", "central processing unit", "CPU", or "MCU" is used to perform a specific function, unless otherwise specified, these functions can be performed by a single unit or multiple units.

[0025] In the present application, the terms “device”, “module” or “unit” may be implemented in the form of hardware or software to achieve specific functions.

[0026] In this application, the terms "calculate", "judge", "control", "determine", "identify", etc. refer to the operations and processes of a computer system or similar electronic computing device (e.g., controller, processor, etc.).

[0027] In order to clearly illustrate the technical solution of the present application, an upper side and a lower side are defined in the drawings of the specification.

[0028] like Figure 1 An electric tool of an embodiment of the present application is shown. The electric tool includes a motor assembly 20. In this embodiment, the electric tool is a circular saw 100. In some embodiments, the electric tool can also be other cutting tools, such as a table saw, a miter saw, a marble saw, a tile saw, a chain saw, etc.

[0029] In some embodiments, the electric tool can also be a garden tool, such as a lawn mower, a hair dryer, a rear-propelled electric tool such as a lawn mower, a cleaning machine, etc. Alternatively, the electric tool can also be a decoration tool, such as a screwdriver / drill / wrench, an electric hammer, a nail gun, a sander, etc. Alternatively, the electric tool can also be, for example, a reciprocating saw, a jigsaw, etc. Alternatively, the electric tool can also be other bench-type tools, such as an electric milling machine, etc. Alternatively, the electric tool can also be a grinding tool, such as an angle grinder, a sander, etc. Alternatively, the electric tool can also be other electric tools, such as a fan, etc. Or non-road-driving walking equipment, such as a multi-purpose vehicle, can also be a beach car, a farmer's car (Utility Terrain Vehicle, UTV), a golf cart, an all-terrain vehicle (All Terrain Vehicle, ATV), and can also be an agricultural machinery vehicle, such as a harvester, a sprayer, etc. Of course, it is understandable that for walking equipment, it can also be a cleaning machine. It can also be an intelligent walking electric tool that uses a motor or a motor assembly to drive walking and implement operating functions, such as an intelligent lawn mower, etc.

[0030] It is understandable that any electric tool driven by a motor can adopt the technical solution disclosed in this embodiment, and any power equipment adopting the technical solution disclosed in this embodiment belongs to the scope of protection of this application. For example, the electric tool can also be a power head, which includes a motor. The power head is used to adapt some output components to realize the function of the tool.

[0031] like Figure 1 As shown, a circular saw 100 is taken as an example. The circular saw 100 is a handheld circular saw, and unless otherwise specified, directional terms such as front, rear, left, right, up and down, etc., are all relative to the direction of normal use of the circular saw 100, such as defining the forward direction of the circular saw 100 as the front direction, and the direction opposite to the forward direction of the circular saw 100 as the rear direction.

[0032] The circular saw 100 includes a power supply 31. In this embodiment, the power supply 31 is a DC power supply. The DC power supply is used to provide electrical energy to the circular saw 100. The DC power supply includes at least one battery pack 31 for providing an energy source for the motor assembly 20. The battery pack 31 cooperates with the corresponding power supply circuit to power the circular saw 100. Those skilled in the art should understand that the power supply is not limited to the scenario of using a DC power supply, and can also be powered by AC power, AC power, and corresponding rectification, filtering and voltage regulation circuits to achieve power supply to the corresponding components in the machine. In the subsequent description, the battery pack 31 will replace the power supply 31, but it cannot be used as a limitation of the present invention.

[0033] The battery pack 31 may be a lithium battery pack, a solid-state battery pack, or a soft-pack battery pack. In some embodiments, when the power supply includes multiple battery packs 31, the types of the battery packs 31 may be the same or different. In some embodiments, the electrical parameters, structural parameters, and physical parameters of the multiple battery packs 31 may be the same or different.

[0034] like Figures 1 to 8 As shown, the circular saw 100 further includes: an output shaft 30, a main body housing 11, a motor assembly 20, a power transmission mechanism 40 and a bottom plate 50. The output shaft 30 is used to mount a cutting member 61. The cutting member 61 rotates around the output axis 301. In this embodiment, the cutting member 61 is a circular saw blade. The motor assembly 20 is used to drive the output shaft 30 to rotate. The power transmission mechanism 40 is used to transmit the output power of the motor assembly 20 to the output shaft 30. The main body housing 11 is used to accommodate parts such as the motor assembly 20 and the power transmission mechanism 40. The output shaft 30 and the cutting member 61 are arranged outside the main body housing 11. The bottom plate 50 is movably connected to the main body housing 11, and the bottom plate 50 is formed with a bottom plate bottom surface 51 that contacts the workpiece. The bottom plate 50 is formed with a saw blade through hole 54 extending along the first direction K1, and the saw blade can pass through the saw blade through hole 54 and protrude downward from the bottom plate bottom surface 51.

[0035] The main housing 11 includes a first housing 111, and the first housing 111 forms or is connected with a gripping portion 12 for grasping. The gripping portion 12 is located at the rear end of the circular saw 100, and can be held by the user to operate the circular saw 100 to perform cutting. In some embodiments, the gripping portion 12 is also provided with a control switch 81 and a safety switch 82, and the control switch 81 can only be triggered when the safety switch 82 is pressed. In other words, the motor or motor assembly 20 can only be started after two actions. Thus, the danger caused by a single operation is avoided. When the user grasps the gripping portion 12, the user's hand grasping the gripping portion 12 can trigger the safety switch 82 and the control switch 81 to start or shut down the circular saw 100. In one embodiment, the first housing 111 can also form a second gripping portion 13. The second gripping portion 13 is located at the front end of the circular saw 100 and is used as an auxiliary handle. In one embodiment, the second gripping portion 13 can also be an external handle installed on the main housing 11, that is, the second gripping portion 13 can be an auxiliary operating component installed separately on the main housing 11.

[0036] The circular saw 100 further includes a guard assembly 60. The guard assembly 60 can at least partially surround the cutting member 61 to protect the environment and the safety of the user. The guard assembly 60 includes a fixed guard 62 of an arc-shaped structure, and a movable guard 63 that rotates relative to the fixed guard 62. The fixed guard 62 is connected to the first housing 111. The movable guard 63 is sleeved in the fixed guard 62 and can rotate around the output axis 301 to be folded into the fixed guard 62. The output shaft 30 extends into the fixed guard 62, and the cutting member 61 and the output shaft 30 are detachably connected. In actual work, different types of cutting members 61 can be used according to the material of the object to be cut. The cutting member 61 is arranged in the fixed guard 62, and almost the upper half of its outer circumference is covered by the fixed guard 62, and the movable guard 63 rotates in the fixed guard 62 to cover or leak the lower half of the cutting member 61. An opening piece 64 of the movable guard 63 is provided between the movable guard 63 and the fixed guard 62 . When the circular saw 100 is used, the operator manually pushes the opening piece 64 to rotate the movable guard 63 to expose part of the saw teeth.

[0037] The bottom plate 50 is movably connected to the fixed shield 62. In this embodiment, a connection seat 52 is provided on the front side of the bottom plate 50, and the connection seat 52 and the fixed shield 62 are connected by a pin 53, so that the fixed shield 62 can rotate relative to the bottom plate 50. The axis where the pin 53 is located is defined as the pivot axis 501. The pivot axis 501 is parallel to the output axis 301. When the fixed shield 62 rotates around the pivot axis 501 relative to the bottom plate 50, the relative position between the fixed shield 62 and the bottom plate 50 will change, resulting in the circular saw 100 having different cutting depths. The rotation of the fixed shield 62 is achieved by applying a force on the grip portion 12, so that the grip portion 12 rotates relative to the bottom plate 50, thereby driving the fixed shield 62 to rotate relative to the bottom plate 50. It can be understood that in some embodiments, the pivot axis 501 and the output axis 301 can intersect or be perpendicular.

[0038] like Figure 6 and Figure 8 As shown, the motor assembly 20 includes a first motor 21 and a second motor 22. The first motor 21 includes a first drive shaft 211 rotating around a first axis 201. The second motor 22 includes a second drive shaft 221 rotating around a second axis 202. The first motor 21 and the second motor 22 include a stator and a rotor, respectively. Taking the first motor 21 as an example, Fig.11 As shown, the stator 212 includes a stator core 2121 and a stator winding 2122. The rotor 214 includes a rotor core 2141 and a permanent magnet 2142. A drive shaft is formed or connected to the rotor 214 for outputting power. For an outer rotor motor, the rotor is sleeved on the outside of the stator. For an inner rotor motor, the stator is sleeved on the outside of the rotor. In this embodiment, the overall structure of the motor here is substantially the same as that of a general brushless motor, and will not be described in detail here.

[0039] The power transmission mechanism 40 is used to transmit the power of at least one of the first motor 21 and the second motor 22 to the output shaft 30. The torque of the first drive shaft 211 and the second drive shaft 221 is output through the output shaft 30. In this embodiment, the first motor 21 and the second motor 22 work together to output the torque of the motor assembly 30 through the output shaft 30, and the torque is output outward through the output shaft 30. Taking the electric circular saw of the present application as an example, the first motor 21 and the second motor 22 work together to drive the cutting member 61 to perform cutting movement through the output shaft 30. Different from the multi-motor driven power tools in the related art, for example, in outdoor walking equipment or wheeled equipment, in the related art, multiple motors such as dual motors are used to drive different output shafts or output parts respectively. For example, in the related art, the first motor and the second motor are used to drive two or more driving wheels or driving shafts respectively. However, in this embodiment, the motor assembly including multiple motors drives the same output shaft, that is, the torque of the driving shafts of multiple motors is output through one output shaft. The end points of the torque transmission paths of the multiple motors are the same, which improves the working efficiency range of the power tool as a whole, so that a power tool with only one output shaft can also be driven efficiently by multiple motors. Compared with multiple motors driving different output parts or output shafts, the present application uses multiple motors to drive one output shaft, and the transmission coordination, power distribution and drive structure of the motor assembly 20 and the power transmission mechanism 40 need to overcome more difficulties.

[0040] like Figures 4 to 10 As shown, the first motor 21 and the second motor 22 are arranged in the radial direction, that is, the first drive shaft 211 and the second drive shaft 221 are arranged in the radial direction of the first drive shaft 211. Alternatively, the first drive shaft 211 and the second drive shaft 221 are arranged in the radial direction of the second drive shaft 221. In this embodiment, the first drive shaft 211 and the second drive shaft 221 are parallel but do not overlap. In this embodiment, the first drive shaft 211 and the second drive shaft 221 are both arranged parallel to the output shaft 30. In some alternative embodiments, the first drive shaft 211 and the second drive shaft 221 intersect or are arranged perpendicularly.

[0041] The main housing 11 includes a receiving housing 14 for receiving the motor assembly 20. The receiving housing 14 is formed or connected to the first housing 111. In the present embodiment, the shield assembly 60 and the receiving housing 14 are basically located on both sides of the first housing 111. It can be understood that the shield assembly 60 is located on the left side of the first housing 111, and the receiving housing 14 is located on the right side of the first housing 111. In the present embodiment, the first housing 111 and the receiving housing 14 are connected to each other. A through hole 1111 is provided on the right side wall of the first housing 111 for the receiving housing 14 to pass through. Among them, the power transmission mechanism 40 is contained in the first housing 111 and is located outside the receiving housing 14. So that the arrangement of the components in the main housing 11 is more reasonable.

[0042] The housing 14 includes a first housing portion 141 for housing the first motor 21 and a second housing portion 142 for housing the second motor 22. Figure 5 and Figure 8 As shown, along the extension direction of the output shaft, the orthographic projection observation is carried out. In the direction of the output axis 301, the ratio of the outer dimension Lc of the projection of the housing 14 along the projection of the first axis 201 and the projection of the second axis 202 to the outer diameter D1, D2 of any motor is greater than or equal to 1.1. When the first motor 21 and the second motor 22 are used to cooperate in controlling the output of the output shaft 30, when the first motor 21 and the second motor 22 are arranged non-coaxially, in order to ensure that the first motor 21 and the second motor 22 can be installed stably, the size of the housing 14 needs to be greater than 1.1 times the diameter of a single motor. In this way, the relative positions of the first motor 21 and the second motor 22 can be reasonably arranged, so that the first motor 21 and the second motor 22 have space to be installed stably. On the other hand, it allows users to easily identify the difference between products controlled by one motor and products controlled by the first motor 21 and the second motor 22 at the same time.

[0043] In this embodiment, taking the second motor 22 as an example, the second motor 22 is an inner rotor motor, and the "motor outer diameter" is the stator outer diameter of the motor. The motor outer diameter of the second motor 21 is D2, and the ratio of the outer dimension Lc of the projection of the housing 14 along the line connecting the projection of the first axis 201 and the projection of the second axis 202 to the outer diameter D2 of the second motor 21 is greater than or equal to 1.2, 1.4, 1.6, 1.8. In some embodiments, the ratio of the outer dimension Lc of the projection of the housing 14 along the line connecting the projection of the first axis 201 and the projection of the second axis 202 to the outer diameter D2 of the second motor 21 is greater than or equal to 2. In some embodiments, the ratio of the outer dimension Lc of the projection of the housing 14 along the line connecting the projection of the first axis 201 and the projection of the second axis 202 to the outer diameter D2 of the second motor 21 is greater than or equal to 2.1, 2.2. In this embodiment, the motor outer diameters of the first motor 21 and the second motor 22 are the same. In terms of arrangement position, the first motor 21 and the second motor 22 are arranged apart from each other in the radial direction. In this embodiment, Figure 6 and Figure 8 As shown, in the direction perpendicular to the bottom surface 51 of the bottom plate, the first motor 21 and the second motor 22 have no overlapping parts. In some embodiments, in the extension direction of the cutting member 61, the first motor 21 and the second motor 22 have no overlapping parts, that is, there is no straight line extending in the direction of the output axis 301 that can pass through the first motor 21 and the second motor 22 at the same time.

[0044] In this embodiment, the first motor 21 and the second motor 22 at least partially overlap in the direction of the output axis 301. That is to say, there is at least one third straight line perpendicular to the output axis 301, which passes through both the first motor 21 and the second motor 22. This makes the size of the motor assembly 20 in the direction of the output axis 301 more compact. In this embodiment, the outer dimension Lc of the projection of the housing 14 in the direction of the line connecting the projection of the first axis 201 and the projection of the second axis 202 is greater than the outer dimension H1 of the housing 14 in the direction of the output axis 301, that is, the radial dimension of the housing 14 is greater than the axial dimension of the housing 14.

[0045] like Figure 6 and Figure 8 As shown, the first housing portion 141 at least supports the first bearing portion 215 of the first motor 21, and the first bearing portion 215 is a bearing portion away from the output shaft 30. The first bearing portion 215 includes a ball bearing. The ball bearing supports the end of the first drive shaft 211 away from the output shaft 30. The bottom surface of the first housing portion 141 is provided with a first bearing seat 1411 supporting the ball bearing. The second housing portion 142 at least supports the second bearing portion 225 of the second motor 22, and the second bearing portion 225 is a bearing portion away from the output shaft 30. The second bearing portion 225 includes a ball bearing. The ball bearing supports the end of the second drive shaft 221 away from the output shaft 30. The bottom surface of the second housing portion 142 is provided with a second bearing seat 1421 supporting the ball bearing. So that the first motor 21 and the second motor 22 are stably installed by the first housing portion 141 and the second housing portion 142 respectively.

[0046] In some alternative embodiments, the first motor 21 and the second motor 22 are arranged to overlap partially in the radial direction, that is, there is at least one fourth straight line parallel to the output axis 301, which passes through both the first motor 21 and the second motor 22. This makes the size of the motor assembly 20 in the radial direction more compact. In this case, the outer dimension Lc of the projection of the housing 14 along the direction of the line connecting the projection of the first axis 201 and the projection of the second axis 202 can be less than or equal to the outer dimension H1 of the housing 14 along the direction of the output axis 301.

[0047] like Figures 7 to 10 As shown, the receiving shell 14 includes: a first marking structure corresponding to the first motor 21 and a second marking structure corresponding to the second motor 22, and the first marking structure and the second marking structure are formed or connected on the outer wall surface of the receiving shell 14. This allows users to easily identify that the first motor 21 and the second motor 22 are used to drive the product. The internal features of the product are externalized to increase the user's participation in product selection.

[0048] In some embodiments, Figure 7As shown, the first marking structure 71a is configured to include a shape that is similar to the partial outline of the first motor 21. The second marking structure 72a is configured to include a shape that is similar to the partial outline of the second motor 22. For example, the first marking structure 71a is the first receiving portion 141 in the receiving shell 14, and the outer wall of the first receiving portion 141 is an arc edge that is similar to the shape of the first motor 21. The second marking structure 72a is the second receiving portion 142 in the receiving shell 14, and the outer wall of the second receiving portion 142 is an arc edge that is similar to the shape of the second motor 22. Or, for example, the first marking structure 71a is the first receiving portion 141 in the receiving shell 14, and the second marking structure 72a is the second receiving portion 142 in the receiving shell 14. There is an obvious depression, or protrusion, or distinguishing shape, or separation mark, etc. between the first receiving portion 141 and the second receiving portion 142, which distinguishes the receiving shell 14 from the partitions associated with the number of motors. It is understandable that the outer wall of the first housing portion 141 can be designed with other shapes from the perspective of industrial design, and the outer wall of the second housing portion 142 can be designed with other shapes from the perspective of industrial design, but in the technical field and in the eyes of ordinary consumers, their shapes can be identified as motors and can be understood as shapes similar to the contours of motors. For example, in addition to the circle that is the same shape as the motor, there are ellipses, shapes formed by the combination of arcs and straight lines, shapes formed by the combination of multiple arcs, rectangles, polygons, triangles and other styling lines.

[0049] In this embodiment, the outer walls of the first marking structure 71a and the second marking structure 72a are configured as a continuous surface. Figure 7 As shown, the outer walls of the first receiving portion 141 and the second receiving portion 142 are continuous structures, that is, the receiving shell 14 is an integral structure.

[0050] In some alternative embodiments, the first marking structure and the second marking structure are configured as independent double-tube structures. The receiving shell 14 may be an integral structure, and the first marking structure and the second marking structure are two closed structures, which are arranged on the outer wall of the receiving shell 14. The receiving shell 14 may also be a structure enclosed by two independent outer walls, namely, the first receiving portion 141 and the second receiving portion 142.

[0051] In some alternative embodiments, such as Figure 7As shown, the first marking structure 71b and the second marking structure 72b are additional line structures arranged on the outer walls of the first housing portion 141 and the second housing portion 142. For example, the first marking structure 71b is a line structure on the outer wall of the first housing portion 141 that is similar to the outline of the motor. The second marking structure 72b is a line structure on the outer wall of the second housing portion 142 that is similar to the outline of the motor. The line structure can be a protruding line, an embedded line, a concave line, or a hollow line. For example, the first marking structure 71b is a line structure on the outer wall of the first housing portion 141 that is associated with representing the motor or the number of motors. The second marking structure 72b is a line structure on the outer wall of the second housing portion 142 that is associated with representing the motor or the number of motors, such as "text", "letters", "numbers" and the like, wherein "representing the motor" is a line structure that can be identified as a motor in the technical field and in the eyes of ordinary consumers.

[0052] In some alternative embodiments, such as Fig. 9 and Fig.10 As shown, the first indicator structure includes the first display parts 71c and 71d, and the second indicator structure includes the second display parts 72c and 72d. The first display parts 71c and 71d, and the second indicator structure includes the second display parts 72c and 72d, which are respectively arranged at positions that are easy to see on the main body housing 11. In this way, when the user is using the circular saw 100, he can use the display parts to confirm the use status of the first motor 21 and the second motor 22 by simply moving his sight.

[0053] In some embodiments, Fig. 9 As shown, the first display unit 71c includes a light emitting body, and the light emitting body at least indicates the on / off state of the first motor 21. For example, the first display unit 71c includes a light emitting diode (LED), a COB (Chip On Board, i.e., chip on board mounting) lamp bead, or an incandescent lamp. The first display unit 71c is arranged on the upper surface of the first shell 111, and the first display unit 71c is arranged on the upper surface portion of the first shell 111 close to the receiving shell 14. In some embodiments, the first display unit 71c is arranged on the upper surface of the receiving shell 14. Among them, the first display unit 71c prompts the on / off state of the first motor 21 through changes in display, for example, through different prompting features such as lighting and extinguishing, constant lighting and flashing, and different colors. The first display unit 71c can also be a plurality of lights or light strips. The speed range of the first motor 21 is prompted by the different display features of lights of different numbers or sections. In some embodiments, the first display unit 71c can also prompt abnormalities as abnormal alarms.

[0054] In some alternative embodiments, such as Fig.10As shown, the first display unit 71d includes a display screen, and the display screen serves as a human-machine interaction interface to display the operating status of the first motor 21. For example, the first display unit 71d includes a light emitting diode (LED) display screen, a liquid crystal display (LCD) display screen, or an organic electroluminescence display (OLED) display screen. The first display unit 71d is arranged on the upper surface of the receiving shell 14. In some embodiments, the first display unit 71d is arranged on the upper surface of the first shell 111, and the first display unit 71d is arranged on the upper surface portion of the first shell 111 close to the receiving shell 14. Among them, since the display screen serves as a human-machine interaction interface, the displayed content is more detailed and more intuitive. Therefore, according to different settings, various information of the first motor 21 during the working process can be displayed on the display screen, such as start and stop information, speed information, output torque information, forward and reverse information, loss information, temperature information, and even the first motor 21 can be intuitively displayed on the display screen in the form of dynamic modeling.

[0055] In some embodiments, the first display unit may include both a light emitter and a display screen. The second display unit 72c includes at least one of a light emitter or a display screen, which is used to indicate the operating state of the second motor 22. That is to say, the first display unit 71c, 71d and the second display unit 72c may be display components of the same type, or may be display components of different types. At the same time, in order to facilitate user observation, the first display unit 71c, 71d and the second display unit 72c are arranged in the same position area, for example, both are arranged on the upper part of the receiving shell 14, one of which is close to the position of the first motor 21, and the other is close to the position of the second motor 22. When the first display unit and the second display unit use the same type of display components, the first display unit and the second display unit can be combined into one, for example, different brightness of LED lights are used, and different colors are used to display different motor start-up coordination. For example, different display areas of the same display interface of the display screen are used to show the information of the first motor 21 and the second motor 22, or different display interfaces are used to respectively show the information of the first motor 21 and the second motor 22, or the menu allows the user to select the display of the first motor 21, the second motor 22, or the information of the first motor 21 and the second motor 22.

[0056] In some embodiments, the first display portion 71e includes an icon representing the first motor 21, the second display portion 72e includes an icon representing the second motor 22, and the first display portion 71e and the second display portion 72e are respectively provided with adhesive layers. That is, the first display portion 71e and the second display portion 72e are adhesive labels. The icon representing the first motor 21 and the icon representing the second motor 22 can be Chinese characters, English characters, graphics, etc. The first display portion 71e and the second display portion 72e can be provided on the same paper with an adhesive layer.

[0057] The technical solutions in the above embodiments may be used partially alone or in combination of several of them, so as to set the specific implementation of the first marking structure and the second marking structure according to the actual needs of the electric tool.

[0058] like Figure 6 and Figures 12 to 16 As shown, the power transmission mechanism 40 is used to transmit the power of at least one of the first motor 21 and the second motor 22 to the output shaft 30. The torque of the first drive shaft 211 and the second drive shaft 221 is output through the output shaft 30. The power transmission mechanism 40 includes: a transmission assembly 41 is configured between at least one of the first motor 21 and the second motor 22 and the output shaft 30. The transmission assembly 41 at least includes a reduction mechanism. The clutch assembly 42 is configured between the first motor 21 and the second motor 22, and the clutch assembly 42 is used to limit or allow at least one of the first drive shaft 211 or the second drive shaft 221 to drive the output shaft 30 under preset conditions. So that the first motor 21 and the second motor 22 can drive the output shaft 30 to work in the range where the respective motor efficiencies are higher. It can be understood that the clutch assembly 42 is configured between the first motor 21 and the second motor 22. On the one hand, in terms of orientation, the clutch assembly 42 has at least a partial overlap with any one of the first motor 21 and the second motor 22 in the axial direction of the drive shaft, or has at least a partial overlap with any one of the first motor 21 and the second motor 22 in the radial direction of the drive. On the other hand, in terms of connection relationship, the clutch assembly 42 has a direct or indirect connection with the first motor 21 and the second motor 22, or a direct or indirect power transmission path.

[0059] The transmission assembly 41 with a speed reduction and amplification is provided to improve the cutting capacity of the circular saw 100 and make the cutting efficiency of the circular saw 100 high. The coupling of the motor assembly 20 enables the circular saw 100 to be used in both light load and high load conditions. At the same time, the performance requirements for the motor in the motor assembly are reduced, and a small diameter motor can be used to achieve the performance requirements of a large motor. This can not only reduce costs, but also reduce the requirements for machine heat dissipation and other aspects.

[0060] The transmission assembly 41 is configured to connect at least one of the first drive shaft 211 and the second drive shaft 221 to the clutch assembly 42. Figures 19 to 21 As shown, as an embodiment, the transmission assembly 41 includes a first gear set 41a for connecting the first drive shaft 211 and the output shaft 30. The transmission assembly 41 also includes a second gear set 41b, connecting the second drive shaft 221 and the output shaft 30, wherein the clutch assembly 42 is arranged between the second gear set 41b and the output shaft 30. In this embodiment, the first gear set 41a is a reduction gear transmission, and the second gear set 41b is a reduction gear transmission. The first gear set 41a is a first-stage reduction transmission, that is, the first gear set 41a provides a reduction motion. The second gear set 41b is a first-stage reduction transmission, that is, the second gear set 41b provides a reduction motion. In some alternative embodiments, the first gear set 41a and the second gear set 41b may also include a multi-stage reduction transmission, or first increase the speed and then reduce the speed. In some alternative embodiments, the transmission ratio or reduction ratio of the first gear set 41a and the second gear set 41b can be adjusted so that a set of gear sets can provide a variety of transmission ratios or reduction ratios. In this embodiment, the reduction ratio of the first gear set 41a is different from that of the second gear set 41b. The first gear set 41a and the second gear set 41b respectively include: cylindrical gear transmission, bevel gear transmission, worm gear transmission, planetary gear transmission, or a combination of several of them.

[0061] The first gear set 41a includes a first driving gear 411 and a first driven gear 412. The first driving gear 411 is formed or connected to the first driving shaft 211. Optionally, the first driving gear 411 is formed at one end of the first driving shaft 211 close to the cutting member 61. The first driving gear 411 rotates around the first axis 201, the first driven gear 412 is externally meshed with the first driving gear 411, the first driven gear 412 is mounted on the output shaft 30, and the first driven gear 412 rotates around the output axis 301. The first driving gear 411 and the first driven gear 412 form a reduction transmission. As an embodiment, the reduction ratio between the first driving gear 411 and the first driven gear 412 is 8 / 38.

[0062] The second gear set 41b includes a second driving gear 413 and a second driven gear 414. The second driving gear 413 is formed or connected to the second drive shaft 221. Optionally, the second driving gear 413 is formed at one end of the second drive shaft 221 close to the cutting member 61. The second driving gear 413 rotates around the second axis 202, the second driven gear 414 is externally meshed with the second driving gear 413, the second driven gear 414 is mounted on the idler shaft 415, and the second driven gear 414 rotates around the third axis 401 of the idler shaft 415. The third axis 401 is parallel to the first axis 201 but does not overlap. The second driving gear 413 and the second driven gear 414 form a reduction transmission. In this embodiment, the clutch assembly 42 includes a one-way transmission member 421. The one-way transmission member 421 is operable to connect the first motor 21 and the second motor 22 to rotate in a first rotation direction, and the one-way transmission member 421 is operable to separate the first motor 21 and the second motor 22 from rotating in a second rotation direction. Optionally, the clutch assembly 42 is a one-way bearing or an overrunning clutch. The one-way transmission member 421 is mounted on the idler shaft 415, and the one-way transmission member 421 rotates synchronously with the second driven gear 414. The inner ring of the one-way transmission member 421 is connected to the idler shaft 415, and the outer ring of the one-way transmission member 421 is connected to the third gear 422. Among them, the third gear 422 is externally meshed with the first driven gear 412 to couple the first motor 21 with the second motor 22. Then the transmission between the second motor 22 and the first motor 21 is controlled. In this embodiment, the third gear 422 and the first driven gear 412 are basically in constant speed transmission, that is, the rotation speed of the third gear 422 is the same as the rotation speed of the first driven gear 412. The transmission ratio between the third gear 422 and the first driven gear 412 is 1. As an embodiment, the reduction ratio between the second driving gear 413 and the second driven gear 414 is 7 / 38.

[0063] During operation, when the first motor 21 starts to work, the first motor 21 drives the output shaft 30 to rotate through the first gear set 41a. Since the setting of the one-way transmission member 421 limits the output speed of the first motor 21 to be transmitted to the second motor 22, that is, the one-way transmission member 421 only allows the second drive shaft 221 (second driving wheel) of the second motor 22 to transmit the rotation to the second driven gear 414. At this time, only the first motor 21 drives the output shaft 30 to rotate. When the second motor 22 starts to start, the rotation lock of the one-way transmission member 421 is released. When the speed of the second driven gear 414 is less than the third gear 422, the speed of the second driven gear 414 cannot be transmitted to the output shaft. It can be understood that when the speed of the power output part (the outer ring in this embodiment) of the one-way clutch is faster than the power source (the inner ring in this embodiment), the one-way clutch is in a disengaged state, and there is no linkage relationship between the inner ring and the outer ring, that is, the one-way overrunning function of the one-way clutch. When the speed of the second driven gear 414 is equal to or higher than the speed of the first driven gear 412, that is, when the speed of the second driven gear 414 is equal to or higher than the speed of the third gear 422, the one-way clutch inner ring and outer ring are linked, and the first motor 21 and the second motor 22 simultaneously drive the output shaft 30 to move. At the same time, the first driven gear 412 is driven by the second driven gear 414 through the third gear 422, so that the first driven gear 412 moves at the speed of the second driven gear 414 (i.e., the idler shaft 415).

[0064] A non-thrust bearing 416 is disposed at the first end of the idler shaft 415 , and an elastic member 417 is disposed at one end of the non-thrust bearing 416 to prevent the gear on the idler shaft 415 from moving.

[0065] In some embodiments, the clutch assembly also includes other mechanical clutch assemblies. For example, a tooth clutch, a ratchet clutch, a centrifugal clutch, a differential, a friction clutch, and a hydraulic clutch. The above mechanical clutches can be used as the clutch assembly of the present application in simple deformation or combination. Under the premise of being able to complete the function of the clutch assembly of the present application, the specific form of the structure does not affect the substantive content of the present application.

[0066] In some embodiments, the clutch assembly further includes an electronic clutch, such as an electromagnetic clutch, such as a dry single-plate electromagnetic clutch, a dry multi-plate electromagnetic clutch, a wet multi-plate electromagnetic clutch, a magnetic powder clutch, or a slip electromagnetic clutch.

[0067] In some embodiments, the coupling of the mechanical clutch assembly and the electronic clutch can be used simultaneously to limit or allow at least one of the first drive shaft 211 or the second drive shaft 221 to drive the output shaft 30 under preset conditions.

[0068] like Fig.15As shown, in the direction of the output axis 301, the projection of the first axis 201 and the projection of the second axis 202 are located above the projection of the output axis 301. So that the motor assembly is located on the upper side of the output shaft. This arrangement can ensure the cutting depth of the circular saw. The output axis 301 is basically the center position of the cutting piece 61. The cutting depth of the circular saw is closely related to the position of the output axis and the bottom plate. The drive axis of the motor assembly is arranged above the output axis, which does not affect the installation and use of the bottom plate of the circular saw. During the cutting depth of the circular saw, there will be no interference with the components close to the bottom plate of the output axis. The angle α between the line connecting the first axis 201 and the output axis 301 and the line connecting the second axis 202 and the output axis 301 is greater than or equal to 45° and less than or equal to 180°. To ensure the first motor and the second motor and the transmission setting, on the other hand, the arrangement structure of the first motor and the second motor and the output shaft is compact.

[0069] Optionally, the first motor 21 and the second motor 22 are staggered in the vertical direction when they are radially arranged. The output shaft 30 and the idler shaft 415 are respectively located on both sides of the first drive shaft 211. The output shaft 30 and the idler shaft 415 are respectively located on both sides of the second drive shaft 221. In this embodiment, the first motor 21 is a small torque output motor, and the second motor 22 is a large torque output motor. At least one gear assembly in the first gear set 41a and the second gear set 41b includes a helical gear.

[0070] like Fig.16 As shown, when the first motor 21e and the second motor 22e are arranged radially, the first drive shaft 211e and the second drive shaft 221e are substantially flush in the vertical direction. The output shaft 30 and the idler shaft 415e are respectively located on the same side of the first drive shaft 211e.

[0071] like Fig.17 As shown, as an embodiment, the first motor 21f and the second motor 22f are arranged radially, and the first driving gear 411f on the first drive shaft 211f and the second driving gear 413f on the second drive shaft 221f are both externally meshed with the driven wheel 412f on the output shaft 30f. At this time, the first motor 21f and the second motor 22f may not be provided with a clutch assembly, that is, the output torque of the first motor and the second motor is synchronized or substantially synchronized. At this time, along the direction of the output axis 301, the projection of the first axis 201 and the projection of the second axis 202 are located above the projection of the output axis 301. The angle α between the line connecting the first axis and the output axis and the line connecting the second axis and the output axis is greater than or equal to 45° and less than or equal to 180°.

[0072] like Figure 18-19As shown, as another embodiment of the present application, the first motor 21g and the second motor 22g are arranged axially. That is, the first drive shaft 211g of the first motor 21g is coaxially arranged with the second drive shaft 221g of the second motor 22g. The first drive shaft 211g is mechanically coupled with the second drive shaft 221g. The first driving gear 411g on the first drive shaft 211g. The first driving gear 411g is externally meshed with the driven wheel 412g on the output shaft 30g. The first driving gear 411g and the driven wheel 412g are reduction transmission. The output axis 301 is not coaxially arranged with the first axis 201. Optionally, the output shaft 30g is parallel to the first drive shaft 211g and is not coaxially arranged. Optionally, the output shaft 30g is parallel to the first drive shaft 211g and the second drive shaft 221g and is not coaxially arranged. Optionally, the output shaft 30g is intersecting with the first drive shaft 211g. Compared with the structure in which the first drive shaft, the second drive shaft and the output shaft are coaxially arranged, the relationship between the three is arranged more reasonably, so that the size of the whole machine will not be too long in the axial direction, making the whole machine layout more compact. At the same time, the radial size of the coaxially arranged first motor and second motor is more compact.

[0073] The receiving shell 14g is used to receive the first motor 21g and the second motor 22g. Optionally, the first receiving portion 141g for receiving the first motor 21g and the second receiving portion 142g for receiving the second motor 22g of the receiving shell 14g are arranged axially. Among them, the ratio of the outer dimension Lc' of the receiving shell 14g along the direction of the first drive shaft 211g or the second drive shaft 221g to the length of any one of the first drive shaft 211g and the second drive shaft 221g is greater than or equal to 1.1. When the first motor 21g and the second motor 22g are coaxially arranged, in order to ensure that the first motor 21g and the second motor 22g can be installed stably, the size of the receiving shell 14g needs to be greater than 1.1 times the length of a single drive shaft. In this way, the relative positions of the first motor 21g and the second motor 22g can be reasonably arranged so that the first motor 21g and the second motor 22g have space to be installed stably. In some embodiments, the ratio of the outer dimension Lc' of the receiving shell 14g along the direction of the first drive shaft 211g or the second drive shaft 221g to the length of any one of the first drive shaft 211g and the second drive shaft 221g is greater than or equal to 1.2, 1.4, 1.6, 1.8. In some embodiments, the ratio of the outer dimension Lc' of the receiving shell 14g along the direction of the first drive shaft 211g or the second drive shaft 221g to the length of any one of the first drive shaft 211g and the second drive shaft 221g is greater than or equal to 2. In some embodiments, the ratio of the outer dimension Lc' of the receiving shell 14g along the direction of the first drive shaft 211g or the second drive shaft 221g to the length of any one of the first drive shaft 211g and the second drive shaft 221g is greater than or equal to 2.1, 2.2.

[0074] like Fig.19 As shown, the first motor 21g is an outer rotor motor, and the second motor 22g is an outer rotor motor. The first motor 21g includes a first stator 212g and a first rotor 214g, and the first drive shaft 211g is formed or connected to the first rotor 214g. The second motor 22g includes a second stator 222g and a second rotor 224g. The second drive shaft 221g is formed or connected to the second rotor 224g.

[0075] The first drive shaft 211g rotates synchronously with the second drive shaft 221g. In this embodiment, the first drive shaft 211g and the second drive shaft 221g are integrally formed. In some implementations, the first drive shaft 211g and the second drive shaft 221g can be separately arranged independent shafts, and the first drive shaft and the second drive shaft are connected by a connector or a fastener to achieve the effect of synchronous rotation. Among them, a motor fixing portion 24g is also included for connecting with the first stator 212g and the second stator 222g respectively. The motor fixing portion 24g is provided with a receiving channel 241g, and the receiving channel 241g is used to receive at least part of the first drive shaft 211g and the second drive shaft 221g, and the receiving channel 241g overlaps at least partially with the first stator 212g along the direction of the first axis 201, and the receiving channel 241g overlaps at least partially with the second stator 222g along the direction of the first axis 201. The stator 212 of the first motor and the stator 222 of the second motor are coaxially connected through the motor fixing portion 24g.

[0076] In some alternative embodiments, a clutch assembly is provided between the first motor shaft and the second motor shaft, or a clutch assembly is provided between the first motor and the output shaft, or a clutch assembly is provided between the second motor and the output shaft, so that the power of the first motor and the second motor can be selectively transmitted to the output shaft. The clutch assembly can be any of the clutch structures in the above embodiments. The clutch assembly is provided in the motor fixing portion, or between the first driving gear 411g and the first driven wheel. At this time, in the direction along the output axis 301, the projection of the first axis 201 and the projection of the second axis 202 are located above the projection of the output axis 301.

[0077] In the present application, the first motor 21 outputs a first torque and a first speed. The second motor 22 outputs a second torque and a second speed. In some embodiments, the first torque is different from the second torque. The first speed and the second speed are different. It needs to be explained that the first torque is different from the second torque. In some embodiments, the output maximum torque of the first motor 21 and the second motor 22 is different, but the output torque of the first motor 21 and the second motor 22 will be the same at one time or one time period during the whole process of operation. In some embodiments, the output torque range of the first motor 21 and the second motor 22 in the high efficiency range is different, but the output torque of the first motor 21 and the second motor 22 will be the same at one time or one time period during the whole process of operation. The first speed and the second speed are different. In some embodiments, the output maximum speed of the first motor 21 and the second motor 22 is different, but the output speed of the first motor 21 and the second motor 22 will be the same at one time or one time period during the whole process of operation. In some embodiments, the output speed range of the first motor 21 and the second motor 22 in the high efficiency range is different, but the output speed of the first motor 21 and the second motor 22 will be the same at one time or one time period during the whole process of operation.

[0078] In some embodiments, the first motor 21 and the second motor 22 are used as an embodiment, and the first motor 21 is a low output torque motor. The second motor 22 is a high output torque motor. Of course, it is also possible that the first motor 21 is a high output torque motor. The second motor 22 is a low output torque motor. Alternatively, the first motor 21 and the second motor 22 are the same motor, but their output speeds and output torques are different. In this embodiment, the first motor 21 and the second motor 22 are both brushless DC motors.

[0079] At the same time, the first motor 21 and the second motor 22 also include at least one different structural parameter. The structural parameters include the outer diameter D of the motor and the motor stack length. It needs to be explained here that the "motor outer diameter" is the outer diameter of the entire motor. "Motor stack length" is the length of the stator core. In this embodiment, the motor diameter of the first motor 21 is less than or equal to 75mm. The motor diameter of the first motor 21 is less than or equal to 70mm. The motor diameter of the first motor 21 is less than or equal to 65mm. In some embodiments, the motor diameter of the first motor 21 is less than or equal to 69mm, 68mm, 67mm, 66mm, 64mm, 63mm, 62mm, 61mm, 60mm, 59mm, 58mm, 57mm, 56mm, 55mm. In this embodiment, the motor diameter of the second motor 22 is less than or equal to 75mm. The motor diameter of the second motor 22 is less than or equal to 70mm. The motor diameter of the second motor 22 is less than or equal to 65mm. In some embodiments, the motor diameter of the second motor 22 is less than or equal to 69 mm, 68 mm, 67 mm, 66 mm, 64 mm, 63 mm, 62 mm, 61 mm, 60 mm, 59 mm, 58 mm, 57 mm, 56 mm, or 55 mm.

[0080] Two motors are used to work together to output the torque of the motor assembly through the output shaft 30. The end points of the torque transmission paths of the multiple motors are the same, which improves the working efficiency range of the power tool. In the related art, in order to ensure the cutting ability of the circular saw, the motor diameter is basically larger than 70mm. In this embodiment, the motor diameter is less than or equal to 70mm, or even smaller, so that the small motor can be used in the circular saw product. At the same time, the two small-diameter motors arranged axially make the size of the whole machine more compact.

[0081] In some embodiments, the structural parameters of the first motor 21 and the second motor 22 include the stator core outer diameter, the stator core inner diameter, the rotor core outer diameter, the rotor core inner diameter, the rotor pole thickness, the stator pole thickness, the air gap length, the core length, the number of stator pole pairs, the corresponding arc of the stator poles, the number of rotor pole pairs, and the corresponding arc of the rotor poles. The first motor 21 and the second motor 22 have at least one structural parameter that is different.

[0082] Of course, in some embodiments, the first motor 21 and the second motor 22 can be two completely identical motors, and a higher efficiency range can be achieved through mutual coupling.

[0083] In this embodiment, the battery pack 31 supplies power to the first motor 21 and the second motor 22. The battery pack 31 cooperates with the corresponding power supply circuit to supply power to the first motor 21 and the second motor 22. Figure 5 and Figure 7As shown, a semi-open battery storage compartment 15 is provided on the main housing 11. The battery storage compartment 15 is provided between the grip portion 12 and the motor assembly 20. The battery storage compartment 15 and the motor assembly 20 are provided on the same side of the first housing 111. The battery storage compartment 15 and the battery pack 31 are provided in front of the grip portion 12. The battery storage compartment 15 is provided on the first housing 111.

[0084] like Fig. 20 As shown, the battery accommodating compartment 15 includes a coupling portion 1511 electrically connected to the battery pack 31, and a tool terminal (not shown in the figure) is arranged on the coupling portion 1511. Tool terminals with the same structure are arranged on different electric tools (not shown in the figure). The battery pack 31 includes: an insertion structure and a terminal interface. The tool terminal is adapted to the terminal interface on the battery pack 31. Tool terminals with the same structure are arranged on different electric tools so that the battery pack 31 can power a variety of different electric tools. The power supply circuit matched therewith is adjusted according to the control requirements of different electric tools. In some embodiments, the nominal voltage of the electric tool is greater than or equal to 18V. The nominal voltage of the electric tool is greater than or equal to 36V and less than or equal to 56V. In some embodiments, the nominal voltage of the electric tool is greater than 56V and less than or equal to 120V. The first motor 21, the second motor 22, the battery pack 31 and the gripping portion 12 are arranged on the same side of the cutting member 61, and after the battery pack 31 is inserted into the battery compartment 15, at least the first motor and the second motor are at least partially arranged, and the battery pack 31 is at least partially arranged before the gripping portion 12. Optionally, the battery pack 31 is inserted into the battery compartment 15 at an angle. In some embodiments, a portion of the battery pack 31 is located above the first motor and the second motor.

[0085] like Fig. 20 As shown, the circular saw 100 further includes a controller 17 for controlling the motor assembly 20. The controller 17 is disposed on a control circuit board 18, and the control circuit board 18 includes: a PCB circuit board (Printed Circuit Board) and an FPC circuit board (Flexible Printed Circuit Board). The controller 17 uses a dedicated control chip, such as a single-chip microcomputer or a microcontroller unit MCU (Microcontroller Unit). It should be noted that the control chip can be integrated into the controller 17, or can be disposed independently of the controller 17. As for the structural relationship between the drive chip and the controller 17, this embodiment does not limit it.

[0086] like Figure 6 and Figure 8As shown, the motor assembly 20 further includes: a first fan 216 supported by the first drive shaft 211, the first fan 216 is driven by the first motor 21 to rotate and generate a heat dissipation airflow. A second fan 226 supported by the second drive shaft 221, the second fan 226 is driven by the second motor 22 to rotate and generate a heat dissipation airflow. Figure 21 to Figure 22 As shown, an air flow port is formed on the main housing 11, and when any one of the first fan 216 and the second fan 226 rotates, a heat dissipation air path can be generated, and the heat dissipation air path at least flows through the control circuit board 18 and the motor assembly 20. The brushless motor has a higher output power than the brushed motor. But at the same time, the heat dissipated by the brushless motor itself will also increase; and the heat dissipated by the control circuit board 18 used to control the power supply of the motor will also increase. Therefore, it is necessary to fully dissipate the heat of the control circuit board 18. In some embodiments, when the first motor and the second motor are coaxially arranged, only the first fan can be set to be supported by at least one of the first drive shaft, the second drive shaft or the output shaft. When any one of the first motor and the second motor rotates, the first fan rotates and produces a heat dissipation air path.

[0087] The airflow port includes a first air inlet 161 and a first air outlet 162. The heat dissipation airflow enters the main housing 11 from the first air inlet 161 and flows out of the main housing 11 from the first air outlet 162. The control circuit board 18 is arranged in the first housing 111. The first air inlet 161 allows the heat dissipation airflow to enter the receiving housing 14 from the first housing 111. When any one of the motors in the motor assembly 20 is started, the corresponding fan rotates synchronously to generate a heat dissipation airflow. The heat dissipation airflow is allowed to flow through at least the control circuit board 18 and the motor assembly 20. In other words, at least one of the control circuit board 18 and the motor assembly 20 needs to be arranged in the flow path of the heat dissipation airflow. In this way, when any one of the motors in the motor assembly 20 is started and the fan rotates, the external air can flow into the interior of the circular saw 100 through the air inlet to form a heat dissipation airflow; and in the process of flowing to the fan, the heat dissipation airflow flows through at least the circuit board and any one of the motors in the motor assembly 20, and finally flows out through the air outlet.

[0088] like Figure 20 to Figure 22As shown, it is a first embodiment of the heat dissipation scheme. The control circuit board 18 is arranged above the motor assembly 20. The plane in which the control circuit board 18 extends is defined as the second plane S2. The plane in which the bottom surface 51 of the bottom plate 50 is located is defined as the third plane S3. In the direction perpendicular to the extension direction of the cutting member 61, that is, in the direction of the output axis, the second plane S2 is a straight line, and the third plane S3 is a straight line. The second plane S2 and the third plane S3 can be parallel or intersecting. The control circuit board 18 is accommodated in the circuit board housing 19. The circuit board housing 19 includes a heat sink 191. In this embodiment, the circuit board housing 19 is made of heat dissipation material, and a heat sink 191 is provided on the side wall in contact with the control circuit board 18. The heat sink 191 includes heat dissipation fins 192 extending a certain length. The control circuit board 18 is connected to the heat sink 191 and can transfer the heat emitted by the control circuit board 18, and the heat of the control circuit board 18 is exported to the heat sink 191 and the heat dissipation fins 192. In this embodiment, the plane in which the heat sink 191 is located is parallel to or coincides with the second plane S2. When the circuit board housing 19 is arranged in the first housing 111 , in order to reduce the flow resistance of the cooling airflow and optimize the cooling effect, the extension direction of the space defined by adjacent sheet-like fins will follow the flow direction of the cooling airflow.

[0089] Among them, the first fan 216 is arranged at one end of the first drive shaft 211 close to the output shaft 30. The first fan 216 is at least partially arranged in the receiving shell 14. The second fan 226 is arranged at one end of the second drive shaft 221 close to the output shaft 30. The second fan 226 is at least partially arranged in the receiving shell 14. The circuit board shell 19 and the control circuit board 18 are arranged radially outside the first fan 216 and the second fan 226. Optionally, the circuit board shell 19 and the control circuit board 18 are arranged radially above the first fan 216 and the second fan 226. The circuit board shell 19 and the control circuit board 18 are arranged in the first shell 111. The first air inlet 161 is arranged on the upper side wall of the first shell 111. In this embodiment, the first air inlet 161 is arranged on the right side wall and the upper side wall of the first shell 111. It can be understood that a part of the first air inlet 161 is located on the upper side wall, and a part is located on a side wall of the first shell 111 away from the output shaft 30. So that the heat dissipation air path can have a longer contact path with the circuit board shell 19. That is, the first air inlet 161 and the fan are basically located on the upper and lower sides and the left and right sides of the control circuit board 18. The first air inlet 161 is configured as a matrix hole formed by multiple through holes to prevent the operator from accidentally inserting fingers into the air flow opening.

[0090] Since the first fan 216 and the second fan 226 are basically located in the receiving shell 14, the receiving shell 14 is provided with a first communication port 146 and a second communication port 147 corresponding to the first fan 216 and the second fan 226, respectively. In some embodiments, the setting positions of the first communication port 146 and the second communication port 147 are specifically determined according to the positions of the first fan 216 and the second fan 226. Of course, the first communication port 146 and the second communication port 147 may not be provided. It is ensured that the cooling airflow flowing through the control circuit board 18 entering from the first air inlet 161 is generated by effectively utilizing the negative pressure generated by the rotation of the fan.

[0091] The airflow port also includes a first air outlet 162 for allowing the heat dissipation airflow to flow out of the main housing 11. The first air outlet 162 connects the receiving housing 14 and the first housing 111 with the external environment. In this embodiment, the air outlet direction of the first air outlet 162 is toward the front side of the circular saw 100. Optionally, the second motor 22 is arranged closer to the front relative to the first motor 21. In some embodiments, airflow guide ribs are arranged in the first housing 111 to guide the heat dissipation airflow so that the heat dissipation airflow flows within the confined space of the airflow guide ribs.

[0092] During the cutting operation, when the bottom surface 51 of the bottom plate abuts against the workpiece to be cut, the control switch 81 is normally triggered, at least the first motor 21 is started, and the saw blade rotates, thereby cutting the workpiece to be cut. At the same time, at least the first fan 216 rotates to form a negative pressure, driving the external air into the interior of the circular saw 100 to dissipate heat. After the fan rotates, the heat dissipation airflow enters the interior of the first housing 111 from the first air inlet 161, first flows through the circuit board housing 19 and the control circuit board 18, and flows through the first motor 21 and the second motor 22 from the first connecting port 146, and flows out from the first air outlet 162.

[0093] In this embodiment, a second air outlet 163 is also included. The second air outlet 163 and the first air outlet 162 have different air outlet directions. In this embodiment, the second air outlet 163 is arranged near the second motor 22, and the second air outlet 163 discharges air in a direction away from the cutting member 61, so that the heat dissipation airflow of the second air outlet 163 has a dust blowing function in addition to the heat dissipation function. The dust generated during the cutting process can be blown away. Optionally, the second air outlet 163 includes a third connecting port 164 for connecting the receiving shell 14, the first shell 111 and the outside world, and a fourth connecting port 165 is arranged on the side wall of the bottom plate 50 for taking into account the dust blowing function. In this embodiment, the heat dissipation air path includes a first heat dissipation air path F1 and a second heat dissipation air path F2, and the first heat dissipation air path F1 is configured so that when at least one of the first motor 21 and the second motor 22 is running, the heat dissipation airflow enters from the first air inlet 161, flows through the control circuit board 18 and the motor assembly 20, and then most of it flows out from the first air outlet 162. The second heat dissipation air path F2 is configured such that when at least one of the first motor 21 and the second motor 22 is running, the heat dissipation airflow enters from the first air inlet 161 , flows through the control circuit board 18 and the motor assembly 20 , and then most of it flows out from the second air outlet 163 .

[0094] In this embodiment, the number of the circuit board housing 19 is one, the number of the controller is at least one, the number of the control circuit boards 18 corresponds to the number of the controllers, and multiple controllers can also be arranged on one control circuit board 18. The circuit board housing 19 can accommodate at least one control circuit board 18. The multiple controllers are connected by communication or electricity.

[0095] like Fig.23 As shown, as an optional embodiment, the number of circuit board housings 19 is two, and the number of control circuit boards 18 is at least two. Using multiple control circuit boards 18 to configure multiple controllers can reduce the capacity requirements for the control circuit board 18. The circuit board housings 19 are placed radially outside the first fan and the second fan. Optionally, the circuit board housing 19 and the control circuit board 18 are arranged radially above the first fan and the second fan 226. Among them, the circuit board housing 19 includes a first circuit board housing 19a and a second circuit board housing 19b, and the structures of the first circuit board housing 19a and the second circuit board housing 19b can be the same to increase versatility. It can also be different, and the specific structures of the first circuit board housing 19a and the second circuit board housing 19b are specifically set according to the different specific positions of the first circuit board housing 19a and the second circuit board housing 19b.

[0096] like Fig.24As shown, as an optional embodiment, the second plane S2 of the circuit board 18 is perpendicular to the third plane S3 in space. Optionally, in the direction perpendicular to the extension direction of the cutting member 61, the projection of the second plane S2 is a plane, and the projection of the third plane S3 is a straight line. The extension direction of the second plane S2 is parallel to the extension direction of the cutting member 61. The control circuit board 18 and the fixed shield are heat-conducted. In this embodiment, the circuit board housing 19 is tightly attached to the fixed shield, so that the heat of the circuit board housing 19 can be radiated and dissipated through the surface of the fixed shield, thereby increasing the heat dissipation path of the control circuit board 18.

[0097] like Fig.25 As shown, it is a second embodiment of the heat dissipation solution. The control circuit board 18 is arranged between the motor assembly 20 and the battery pack 31. Optionally, the control circuit board 18 is arranged in the first housing 111 and is located between the storage housing and the battery accommodating compartment 15. In the direction perpendicular to the extension of the cutting member 61, the second plane S2 is a straight line, the third plane S3 is a straight line, and the second plane S2 intersects or is perpendicular to the third plane S3.

[0098] The structure of the motor assembly is the same as that of the first embodiment of the heat dissipation solution. The circuit board housing 19 and the control circuit board 18 are arranged on the radial outside of the first fan 216 and the second fan 226. Optionally, the circuit board housing 19 and the control circuit board 18 are arranged on the radial rear side of the first fan 216 and the second fan 226, between the battery receiving compartment 15 and the receiving housing 14. The second air inlet 166 is arranged in the battery receiving compartment 15. In this embodiment, as shown in FIG. Figure 7 As shown, the battery storage compartment 15 includes at least one first outlet 151 for the battery pack 31 to enter and be pulled out of the battery storage compartment 15, and a second outlet 152 different from the first outlet 151. Figure 7 and Fig.25 As shown, the second air inlet 166 includes a first outlet 151, a second outlet 152, and a fifth connecting port 167 connecting the battery receiving compartment 15 and the first housing 111. It can be understood that the fifth connecting port 167 is an airflow port for allowing the heat dissipation airflow to flow out of the battery receiving compartment 15. In order to make the heat dissipation of the heat dissipation airflow more sufficient, the fifth connecting port 167 is arranged above the first fan 216 and the second fan 226, and the fifth connecting port 167 is at least arranged below the first outlet 151.

[0099] like Figure 7As shown, since the first fan 216 and the second fan 226 are basically located in the receiving shell 14, the receiving shell 14 is provided with a first communication port 146 and a second communication port 147 corresponding to the first fan 216 and the second fan 226, respectively. In some embodiments, the setting positions of the first communication port 146 and the second communication port 147 are specifically determined according to the positions of the first fan 216 and the second fan 226. Of course, the first communication port 146 and the second communication port 147 may not be provided. It is ensured that the cooling airflow flowing through the battery pack 31 and the control circuit board 18 entering from the second air inlet 166 is effectively utilized by the negative pressure generated by the rotation of the fan.

[0100] like Figure 7 and Fig.25 As shown, the air flow port also includes a first air outlet 162 for allowing the heat dissipation airflow to flow out of the main body housing 11. The first air outlet 162 connects the receiving housing 14 and the first housing 111 with the external environment. In this embodiment, the air outlet direction of the first air outlet 162 is toward the front side of the circular saw 100. Optionally, the second motor 22 is arranged closer to the front relative to the first motor 21. In some embodiments, airflow guide ribs are arranged in the first housing 111 to guide the heat dissipation airflow so that the heat dissipation airflow flows within the confined space of the airflow guide ribs.

[0101] During the cutting operation, when the bottom surface 51 of the base plate abuts against the workpiece to be cut, the control switch 81 is triggered normally, at least the first motor 21 is started, and the saw blade rotates, thereby cutting the workpiece to be cut. At the same time, at least the first fan 216 rotates to form a negative pressure, driving the external air into the interior of the circular saw 100 to dissipate heat. After the fan rotates, the heat dissipation airflow enters the battery compartment 15 and the first shell 111 from the second air inlet, flows through the battery pack 31, the circuit board shell 19 and the control circuit board 18, and flows through the first motor 21 and the second motor 22 from the first connecting port 146, and flows out through the first air outlet 162.

[0102] In the present embodiment, a second air outlet 163 is also included. The air outlet directions of the second air outlet 163 and the first air outlet 162 are different. In the present embodiment, the second air outlet 163 is arranged near the second motor 22, and the second air outlet 163 discharges air in a direction away from the saw blade, so that the heat dissipation airflow of the second air outlet 163 has a dust blowing function in addition to the heat dissipation function. The dust generated during the cutting process can be blown away. Optionally, the second air outlet 163 includes a third connecting port 164 for connecting the containing shell 14, the first shell 111 and the outside world, and a fourth connecting port 165 is arranged on the side wall of the bottom plate 50 to take into account the dust blowing function. Fig.25As shown, the air path includes a first heat dissipation air path F1 and a second heat dissipation air path F2. The first heat dissipation air path F1 is configured such that when at least one of the first motor 21 and the second motor 22 is in operation, the heat dissipation airflow enters from the second air inlet 166, flows through the battery pack 31, the control circuit board 18, and the motor assembly 20, and then most of it flows out from the first air outlet 162. The second heat dissipation air path F2 is configured such that when at least one of the first motor 21 and the second motor 22 is in operation, the heat dissipation airflow enters from the second air inlet 166, flows through the battery pack 31, the control circuit board 18, and the motor assembly 20, and then most of it flows out from the second air outlet 163.

[0103] In some embodiments, the circular saw 100 is provided with a first air inlet 161 and a second air inlet 166 to allow for more adequate heat dissipation of the control circuit board 18 and the motor assembly 20 .

[0104] In this embodiment, the number of the circuit board housing 19 is one, the number of the controller is at least one, the number of the control circuit boards 18 corresponds to the number of the controllers, and multiple controllers can also be arranged on one control circuit board 18. The circuit board housing 19 can accommodate at least one control circuit board 18. The multiple controllers are connected by communication or electricity.

[0105] like Fig.26 As shown, as an optional embodiment, the number of circuit board housings 19 is two, and the number of control circuit boards 18 is at least two. Using multiple control circuit boards 18 to configure multiple controllers can reduce the capacity requirements for the control circuit board 18. The circuit board housing 19 and the control circuit board 18 are arranged on the radial outside of the first fan 216 and the second fan 226. Optionally, the circuit board housing 19 and the control circuit board 18 are arranged on the radial rear side of the first fan 216 and the second fan 226, between the battery accommodating compartment 15 and the accommodating housing 14. Among them, the circuit board housing 19 includes a first circuit board housing 19a and a second circuit board housing 19b. The first circuit board housing 19a and the second circuit board housing 19b. The structures can be the same to increase versatility. They can also be different, and the specific structures of the first circuit board housing 19a and the second circuit board housing 19b are specifically set according to the different specific positions of the first circuit board housing 19a and the second circuit board housing 19b.

[0106] like Figures 1 to 5 As shown, the cutting member 61 in this embodiment is a circular saw 100 blade having an outer diameter greater than 6 inches. In some embodiments, the circular saw 100 blade has an outer diameter ranging from about 6 inches to 12 inches. Figure 2 and Figure 3 As shown, along the direction perpendicular to the cutting member 61, the projection of the center of gravity G of the circular saw 100 is located between the rear edge of the base plate 50 and the output axis 301. Figure 2As shown, it is the first state of the circular saw 100, at which time the fixed shield 62 is rotated to the minimum angle relative to the base plate 50 about the pivot axis 501. The ratio of the distance L1 between the projection of the center of gravity G of the circular saw 100 to the output axis 301 and the distance L2 between the rear edge of the base plate 50 and the output axis 301 is less than or equal to 1. In some embodiments, the ratio of the distance L1 between the projection of the center of gravity G of the circular saw 100 to the output axis 301 and the distance L2 between the rear edge of the base plate 50 and the output axis 301 is less than or equal to 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2. The center of gravity G of the circular saw 100 is closer to the output axis 301, but is always located on the rear side of the output axis 301, that is, on the side of the output axis 301 close to the grip 12. As shown in FIG. Figure 3 As shown, the circular saw 100 is in the second state, when the fixed shield 62 is rotated to the maximum angle relative to the base plate 50 about the pivot axis 501 , the distance L1 ′ from the center of gravity of the circular saw 100 to the output axis 301 is the smallest.

[0107] like Figure 4As shown, the cutting member 61 extends in a cutting plane S4, and the gripping portion 12 is basically symmetrically arranged about the first plane S1. In the direction perpendicular to the bottom surface 51 of the base plate, the projection of the first drive shaft 201 and the projection of the second drive shaft 202 have two endpoints that are farthest apart in the direction of the output axis 301. A width interval W is defined between two straight lines on the projection plane that pass through one endpoint respectively and are perpendicular to the output axis 301, and the projection of the center of gravity G of the circular saw is set within the width interval W. In one embodiment, the first motor and the second motor are arranged radially and the first drive shaft and the second drive shaft are arranged parallel to each other. In the direction perpendicular to the bottom surface 51 of the base plate, the projections of the first drive shaft and the second drive shaft include a first endpoint closest to the cutting member and a second endpoint farthest from the cutting member. The first endpoint and the second endpoint are the limit endpoints in the left and right directions of the circular saw when the first drive shaft and the second drive shaft are regarded as a whole. The width interval W is defined between the straight line passing through the first end point and perpendicular to the output axis and the straight line passing through the second end point and perpendicular to the output axis, that is, the width interval W is the position interval of the whole machine within this width, and the width interval is not only the front and rear range of the motor assembly in the front and rear direction of the circular saw, but the front and rear range of the whole circular saw. In one embodiment, the first motor and the second motor are arranged radially and the first drive shaft and the second drive shaft are arranged to intersect. In the direction perpendicular to the bottom surface 51 of the bottom plate, the projections of the first drive shaft and the second drive shaft include a first end point closest to the cutting piece and a second end point farthest from the cutting piece, and the first end point and the second end point are the limit end points in the left and right direction of the circular saw when the first drive shaft and the second drive shaft are regarded as a whole. The width interval W is defined between the straight line passing through the first end point and perpendicular to the output axis and the straight line passing through the second end point and perpendicular to the output axis, that is, the width interval W is the position interval of the whole machine within this width, and the width interval is not only the front and rear range of the motor assembly in the front and rear direction of the circular saw, but the front and rear range of the whole circular saw.

[0108] In one embodiment, when the first motor and the second motor are arranged coaxially, in the direction perpendicular to the bottom surface 51 of the bottom plate, the projections of the first drive shaft and the second drive shaft include a first end point closest to the cutting piece and a second end point farthest from the cutting piece. The first drive shaft and the second drive shaft are arranged left and right in the left and right directions of the circular saw, so the first end point is the leftmost end and the second end point is the rightmost end. The straight line passing through the first end point and perpendicular to the output axis and the straight line passing through the second end point and perpendicular to the output axis are defined as a width interval W, that is, the width interval W is the position interval of the entire machine within this width. The width interval is not only the front and rear range of the motor assembly in the front and rear direction of the circular saw, but the front and rear range of the entire circular saw.

[0109] When the circular saw 100 uses the first motor and the second motor to cooperatively drive the output shaft to move, the working efficiency and cutting ability of the circular saw are improved, but at the same time the weight of the motor assembly will be heavier than that of a circular saw using only one motor. The position of the center of gravity G of the circular saw is reasonably set so that the circular saw with the first motor and the second motor will not cause a poor operating feel of the circular saw 100 during operation, so that when the circular saw is operated, the center of gravity is set within the width range of the first motor and the second motor in the width direction, and the force applied by the entire machine is more stable during operation.

[0110] In some embodiments, along the direction perpendicular to the bottom surface 51 of the bottom plate, the projection of the center of gravity G of the circular saw 100 is located between the projection of the cutting plane S4 and the right edge of the projection of the bottom plate, that is, the projection of the center of gravity G of the circular saw 100 is located within the projection of the bottom plate, but the left side does not exceed the cutting plane S4. At the same time, the center of gravity G of the circular saw 100 is located near the first plane S1. Optionally, the distance from the projection of the center of gravity G of the circular saw 100 to the first plane S1 is less than the distance from the center of gravity G of the circular saw 100 to the cutting plane S4. Optionally, the ratio of the distance W1 between the projection of the center of gravity G of the circular saw 100 to the first plane S1 and the distance W2 from the cutting plane S4 to the first plane S1 is less than or equal to 1 / 3. In some embodiments, the center of gravity G of the circular saw 100 is arranged on the first plane S1 as much as possible, so as not to cause a bad operating feel of the circular saw 100 during operation. Optionally, the center of gravity G of the circular saw 100 can be located on the left or right side of the first plane S1.

[0111] The bottom plate 50 is formed with a hole extending in the first direction K1 so that the cutting member 61 passes through the bottom plate 50. Figure 5 As shown, along the first direction K1, the ratio of the outer edge dimension L3 of the receiving shell 14 to the outer edge dimension La of the host shell 11 is greater than or equal to 0.2 and less than or equal to 0.4. It can be understood that in some embodiments, the outer edge dimension L3 of the receiving shell 14 and the outer side dimension Lc of the receiving shell 14 along the perpendicular direction of the first drive shaft 211 and the second drive shaft 221 can be the same.

[0112] like Figure 4 and Figure 8 As shown, along the direction of the output axis 301 , the ratio of the outer edge dimension H1 of the receiving shell 14 to the outer edge dimension Ha of the main body shell 11 is greater than or equal to 0.15 and less than or equal to 0.4.

[0113] like Fig. 27 As shown, the controller 17 is used to control the motor assembly 20. The controller 17 is configured to determine the start-up state of the first motor 21 and the second motor 22 according to a preset condition.

[0114] As an embodiment, the controller includes a first controller 171 and a second controller 172, that is, dual MCU control. In this embodiment, the first controller 171 includes a first power module, a first PWM drive control module and a first ADC (Analogue Digital Converter Unit) drive module. The second controller 172 includes a second power module, a second PWM drive control module and a second ADC (Analogue Digital Converter Unit) drive module. The battery pack 31 supplies power to the first controller 171 and the second controller 172 respectively. The first controller 171 is connected to the first motor 21, and the second controller 172 is connected to the second motor 22. It can be understood that the first controller 171 and the second controller 172 are connected in serial communication, but also have relatively independent control modules.

[0115] The first controller 171 collects electrical characteristic parameters such as phase current and bus voltage through the first ADC drive module, and sends the detected parameters to the first PWM drive control module of the first controller 171 in signal mode. The first PWM drive control module controls the start and operation of the first motor 21 through PWM signals. The second controller 172 collects electrical characteristic parameters such as phase current and bus voltage through the second ADC drive module, and sends the detected parameters to the first PWM drive control module of the second controller 172 in signal mode. The second PWM drive control module controls the start and operation of the second motor 22 through PWM signals. It is equivalent to providing two independent control circuits to control the first motor 21 and the second motor 22. Among them, the electrical characteristic parameters can also include parameters such as bus current, current storage time, and demagnetization time.

[0116] In the present embodiment, the first motor 21 and the second motor 22 are three-phase brushless motors, respectively. They include three-phase stator windings U, V, and W that are electronically commutated. In some embodiments, the three-phase stator windings U, V, and W are star-connected, and in other embodiments, the three-phase stator windings U, V, and W are angle-connected. However, it must be understood that other types of brushless motors are also within the scope of the present disclosure. The brushless motor may include less than or more than three phases. The drive circuit is electrically connected to the stator windings U, V, and W of the motor, and is used to transfer current from the battery pack 31 to the stator windings U, V, and W to drive the motor to rotate.

[0117] like Fig.29 As shown, the specific control process is as follows: S210: The control switch 81 is activated.

[0118] During operation, the first controller 171 detects that the control switch 81 is activated, that is, receives a start signal.

[0119] S220: The first motor meets the starting condition. If yes, execute S240; if not, execute S230.

[0120] S230: The first motor does not start, and the second motor does not start.

[0121] S240: The first motor is started, and the second motor is not started.

[0122] The first controller 171 controls the first motor 21 to start with a first preset step length.

[0123] S250: The operation of the first motor meets a preset condition, for example, the rotation speed is greater than a first preset rotation speed. If so, execute S260; if not, execute S240.

[0124] S260: Send a second motor start signal.

[0125] S270: The second motor meets the starting conditions. If yes, execute S290; if no, execute S280 S280: The first motor starts, and the second motor does not start.

[0126] S290: The first motor is started, the second motor is started, and they are operated under preset conditions, for example, they are respectively operated at full duty cycle.

[0127] The first controller 171 sends a signal to the second controller controlling the second motor 22, so that the second controller starts the second motor 22. The second controller 172 controls the second motor 22 to start at a second preset step length. The second preset step length is greater than or equal to the first preset step length to shorten the start-up experience time of the two motors. In this embodiment, when the first motor 21 starts stably, the first motor 21 runs at a full duty cycle. When the second motor 22 starts stably, both the first motor 21 and the second motor 22 run at a full duty cycle. It can be understood that the change in motor speed can be obtained by modulation and calculation of the electrical characteristic parameters of the motor, such as phase current. The full duty cycle does not necessarily refer to a duty cycle of 100%. The full duty cycle refers to the maximum duty cycle in the product performance specification, which can be a duty cycle of 90%, a duty cycle of 80%, etc.

[0128] S300: The control switch is released, S230 is executed, the first motor does not start, and the second motor does not start.

[0129] As an example, Fig.28As shown, the controller 17 includes a first controller 171 and a second controller 172, and the first controller 171 and the second controller 172 are arranged on the same control circuit board 18, or are respectively placed on different control circuit boards but the two control circuit boards are in communication connection. The first controller 171 controls the first motor 21, and the second controller 172 controls the second motor 22. In this embodiment, the first controller 171 and the second controller 172 communicate in series. A driver is also provided, including a first drive circuit 173a and a second drive circuit 173b, wherein the first drive circuit 173a is connected to the first controller 171 and the battery pack 31. The second drive circuit 173b is connected to the second controller 172 and the battery pack 31. That is, the battery pack 31 is connected to the drive circuit, and the controller is powered by the drive circuit.

[0130] In the present embodiment, the first motor 21 and the second motor 22 are three-phase brushless motors, respectively. They include three-phase stator windings U, V, and W that are electronically commutated. In some embodiments, the three-phase stator windings U, V, and W are star-connected, and in other embodiments, the three-phase stator windings U, V, and W are angle-connected. However, it must be understood that other types of brushless motors are also within the scope of the present disclosure. The brushless motor may include less than or more than three phases.

[0131] Taking the first drive circuit 173a as an example, the drive circuit 173a is electrically connected to the stator windings U, V, and W of the motor, and is used to transfer the current from the battery pack 31 to the stator windings U, V, and W to drive the motor to rotate. The first drive circuit 173a includes a plurality of switch elements Q1, Q2, Q3, Q4, Q5, and Q6. The gate terminal of each switch element is electrically connected to the first controller 171 for receiving a control signal from the first controller 171. The drain or source of each switch element is connected to the stator windings U, V, and W of the first motor 21. The switch elements Q1-Q6 receive control signals from the first controller 171 to change their respective conduction states, thereby changing the current loaded by the battery pack 31 on the stator windings U, V, and W of the first motor 21. In one embodiment, the first drive circuit 173a may be a three-phase bridge driver circuit including six controllable semiconductor power devices (such as FET, BJT, IGBT, etc.). In some embodiments, the drive circuit 173a may also include more than six controllable semiconductor power devices. It is understandable that the above-mentioned switching element may also be any other type of solid-state switch, such as an insulated gate bipolar transistor (IGBT), a bipolar junction transistor (BJT), etc.

[0132] The controller specifically controls the on or off state of the switch element in the drive circuit by controlling the chip. In some embodiments, the controller controls the ratio between the on time and the off time of the drive switch based on a pulse width modulation (PWM) signal. In this embodiment, the first controller 171 includes a first PWM drive control module. The second controller 172 includes a second PWM drive control module.

[0133] The first controller 171 further includes a first ADC driving module, through which electrical characteristic parameters such as phase current and bus voltage are collected. The second controller 172 further includes a second ADC driving module, through which electrical characteristic parameters such as phase current and bus voltage are collected.

[0134] When the power circuit between the battery pack 31 and the drive circuit is connected, the drive circuit transmits the current of the battery pack 31 to the controller. That is, the first drive circuit 173a transmits the current to the first controller 171, and the second drive circuit 173b transmits the current to the second controller 172. The first controller 171 detects the preset parameters through the first ADC drive module, and sends the detected parameters to the first PWM drive control module of the first controller 171 in a signal mode. The first PWM drive control module sends the PWM control signal to the first drive circuit 173a, and controls the ratio between the on time and the off time of the drive switch based on the PWM control signal. The second controller 172 detects the preset parameters through the second ADC drive module, and sends the detected parameters to the second PWM drive control module of the second controller 172 in a signal mode. The first PWM drive control module sends the PWM control signal to the second drive circuit 173b, and controls the ratio between the on time and the off time of the drive switch based on the PWM control signal. The preset parameters include phase current, bus voltage, bus current, current storage time, demagnetization time and other parameters. The preset parameter detected by the first controller 171 and the preset parameter detected by the second controller 172 may be the same or different.

[0135] like Fig.30 As shown, the specific control process is as follows: S411: The control switch 81 is activated.

[0136] During operation, the first controller 171 detects that the control switch 81 is activated, that is, receives a start signal.

[0137] S412: The first motor meets the starting condition. If yes, execute S141, if not, execute S413.

[0138] S413: The first motor does not start, and the second motor does not start.

[0139] S414: The first motor is started, and the second motor is not started.

[0140] The first controller 171 controls the first motor 21 to start.

[0141] S415: The operation of the first motor meets the first preset condition, for example, the rotation speed is greater than the first preset rotation speed. If yes, execute S414, if not, execute S416 and S417.

[0142] Taking the rotation speed as an example, the first controller 171 first determines the relationship between the rotation speed of the first motor 21 and the first rotation speed threshold. If the rotation speed of the first motor 21 is higher than the first rotation speed threshold, the first motor 21 maintains the current running state to drive the output shaft 30, and the second motor 22 does not need to be started. Optionally, the first rotation speed threshold is 5000RPM.

[0143] S416: The second motor is started and operates under the second preset condition.

[0144] Optionally, the second motor 22 enters a hot standby state, that is, the second motor is started and maintains a ready state for operation under a second preset condition. Optionally, still taking the speed as an example, the second preset speed is less than the first speed threshold, and the second preset speed is the optimal output efficiency speed of the second motor. Optionally, the second preset speed is 4500RPM.

[0145] S417: The operation of the first motor meets the second preset condition, for example, the rotation speed is greater than the second preset rotation speed. If yes, execute S415, if not, execute S418.

[0146] S418: The second motor operates at the third preset condition, and the first motor operates at the second preset condition.

[0147] When the speed of the first motor 21 is less than the preset second preset speed, the second motor 22 is started to run under the third preset condition. At the same time, the first motor 21 is controlled to output at the second preset speed. Optionally, the third preset condition is to control the second motor 22 to run at the maximum duty cycle when the startup is completed. The first motor runs at a constant speed at the second preset speed. That is to say, at this time, both the first motor 21 and the second motor 22 start to drive the output shaft. Then enter the dual motor mode.

[0148] S419: The operation of the first motor meets the fourth preset condition, for example, the rotation speed is less than the fourth preset rotation speed. If yes, execute S420; if no, execute S418.

[0149] The speed of the first motor is continuously detected during the operation process. When the operation of the first motor 21 meets the fourth preset condition, optionally, when the speed is not less than the fourth preset speed, it is determined that the output torque of the motor assembly can meet the required torque of the current output shaft. Optionally, the fourth preset speed is less than the second preset speed, for example, the fourth preset speed is 3500RPM.

[0150] S420: The first motor and the second motor are respectively operated at full duty cycle.

[0151] When the speed is less than the fourth preset speed, it is determined that the output torque of the motor assembly needs to be increased, and the first motor 21 and the second motor 22 are controlled to run at full duty cycle, respectively. The maximum duty cycle of the first motor 21 and the maximum duty cycle of the second motor 22 may be the same or different.

[0152] To avoid frequent switching between single and dual motor modes, in actual applications, in dual motor mode, if the speed is higher than 5000RPM and the current is lower than the current threshold for a preset time, it will switch to single motor operation.

[0153] S421: The control switch is released, and S413 is executed, the first motor does not start, and the second motor does not start.

[0154] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the above embodiments do not limit the present application in any form, and any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present application.

Claims

1. A circular saw comprising: An output shaft is used to mount a cutting member; the cutting member rotates around the output axis; a first motor including a first drive shaft that rotates about a first axis; Second motor; The invention comprises a second drive shaft rotating around a second axis; the second drive shaft is coaxially arranged with the first drive shaft; the first motor and the second motor are mechanically coupled; the motor diameter of the first motor is less than or equal to 70 mm, and the motor diameter of the second motor is less than or equal to 70 mm; a power transmission mechanism for transmitting power of at least one of the first motor and the second motor to the output shaft; The power transmission mechanism includes a transmission assembly, and the transmission assembly includes at least a reduction mechanism; A power supply, comprising at least one battery pack for providing an energy source for the motor; A main body housing at least partially accommodates the first motor, the second motor and the power transmission mechanism; the main body housing includes a first housing, and the first housing is formed with or connected to a gripping portion for gripping; The bottom plate is movably connected to the main body shell, and the bottom plate is formed with a bottom surface that contacts the workpiece.

2. The circular saw according to claim 1, characterized in that The first motor is an outer rotor motor, and the second motor is an outer rotor motor.

3. The circular saw according to claim 1, characterized in that The first drive shaft rotates synchronously with the second drive shaft.

4. The circular saw according to claim 3, characterized in that The first motor includes a first stator and a first rotor, and the first drive shaft is formed or connected to the first rotor; the second motor includes a second stator and a second rotor; and the second drive shaft is formed or connected to the second rotor.

5. The circular saw according to claim 4, characterized in that It also includes a motor fixing part, which is connected to the first stator and the second stator respectively.

6. The circular saw according to claim 5, characterized in that The motor fixing portion is provided with a receiving channel, and the receiving channel is used to receive at least part of the first driving shaft and the second driving shaft.

7. The circular saw according to claim 6, characterized in that The receiving channel at least partially overlaps with the first stator along the first axis direction, and the receiving channel at least partially overlaps with the second stator along the first axis direction.

8. The circular saw according to claim 1, characterized in that The output shaft is not coaxially arranged with the first drive shaft.

9. The circular saw according to claim 8, characterized in that In the direction along the output axis, the projection of the first axis and the projection of the second axis are located above the projection of the output axis.

10. The circular saw according to claim 8, characterized in that In the direction perpendicular to the bottom surface of the base plate, the projection of the first drive axis and the projection of the second drive axis have two endpoints that are farthest apart in the direction of the output axis. A width interval W is defined between two straight lines on the projection plane that pass through one of the endpoints respectively and are perpendicular to the output axis. The projection of the center of gravity of the circular saw is set within the width interval W.

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