Circular saw

Abstract

The utility model 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 power transmission mechanism transmits power of at least one of the first motor and the second motor to the output shaft; torque of the first driving shaft and the second driving shaft is output through the output shaft. The bottom plate is movably connected with the main machine shell, and a bottom plate bottom surface in contact with a workpiece is formed on the bottom plate; in the extending direction perpendicular to the cutting piece, the projection of the gravity center of the circular saw is located between the rear edge of the bottom plate and the output axis. The electric tool is driven by two motors in a matched mode, and a user can use the tool more comfortably.

Description

Technical Field

[0001] The present application relates to a power tool, and more particularly to a circular saw. Background Art

[0002] When the power tool in the related art is working, the output mechanism usually needs to work under both light load conditions 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 a large power and output torque is usually provided in the power tool, and the high-power motor can drive the output mechanism to drive 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. When in light load, the working state of the motor is reduced, affecting the service time of the power tool.

[0003] This section provides background information related to the present application, and these background information are not necessarily prior art. Summary of the Utility Model

[0004] An object of the present application is to solve or at least alleviate part or all of the above problems. To this end, an object of the present application is to provide a circular saw that uses two motors to cooperate to drive the output shaft to output work and has a good working feel.

[0005] To achieve the above object, the present application adopts the following technical solutions:

[0006] A circular saw, comprising: an output shaft for mounting a cutting member; the cutting member rotates about an output axis; a first motor including a first drive shaft rotating about a first axis; a second motor; including a second drive shaft rotating about a second axis; a power transmission mechanism for transmitting the power of at least one of the first motor and the second motor to the output shaft; the torques of the first drive shaft and the second drive shaft are output through the output shaft; a power supply including at least one battery pack for providing an energy source for the motor; a main body housing at least partially accommodating the first motor, the second motor and the power transmission mechanism; the main body housing includes a first housing, and the first housing forms or is connected with a gripping portion for gripping; a bottom plate movably connected to the main body housing, and the bottom plate forms a bottom surface of the bottom plate in contact with the workpiece; when observed in a front projection along the extending direction of the output shaft, the projection of the center of gravity of the circular saw is located between the rear edge of the bottom plate and the output axis.

[0007] In some embodiments, the projection of the center of gravity of the circular saw is close to the output axis and is located behind the output axis.

[0008] In some embodiments, the cutting member extends in a cutting plane; the gripping portion is substantially symmetrically arranged with respect to the first plane; along the direction perpendicular to the bottom plate, the projection of the center of gravity of the circular saw is located between the cutting plane and the right edge of the bottom plate or is substantially located on the first plane.

[0009] In some embodiments, the distance from the center of gravity of the circular saw projected onto the first plane is less than the distance from the center of gravity of the circular saw to the cutting plane.

[0010] In some embodiments, the ratio of the distance W1 between the projection of the center of gravity of the circular saw onto the first plane and the distance W2 from the cutting plane to the first plane is less than or equal to 1 / 3.

[0011] In some embodiments, the first motor, the second motor, the battery pack, and the holding portion are disposed on the same side of the cutting member, and at least a part of the battery pack is disposed behind at least a part of the first motor and the second motor, and at least a part of the battery pack is disposed in front of the holding portion.

[0012] In some embodiments, the first housing forms or is connected to a receiving housing for receiving the first motor and the second motor.

[0013] In some embodiments, the bottom plate is formed with a hole extending in the first direction to allow the cutting member to pass through the bottom plate. Along the first direction, the ratio of the outer dimension L3 of the receiving housing to the outer dimension La of the main housing is greater than or equal to 0.2 and less than or equal to 0.4.

[0014] In some embodiments, along the output axis direction, the ratio of the outer dimension H1 of the receiving housing to the outer dimension Ha of the main housing is greater than or equal to 0.15 and less than or equal to 0.4.

[0015] In some embodiments, the cutting member has an outer diameter greater than 6 inches.

[0016] A circular saw, comprising: an output shaft for mounting a cutting member; the cutting member rotates about an output axis; a first motor including a first drive shaft rotating about a first axis; a second motor including a second drive shaft rotating about a second axis; a power transmission mechanism for transmitting the power of at least one of the first motor and the second motor to the output shaft; a power supply including at least one battery pack for providing an energy source to the motor; a main housing at least partially receiving the first motor, the second motor, and the power transmission mechanism; a bottom plate movably connected to the main housing, the bottom plate forming a bottom surface of the bottom plate in contact with the workpiece; in a direction perpendicular to the bottom surface of the bottom plate, the projections of the first drive shaft and the second drive shaft have two end points that are the farthest apart in the output axis direction, and a width interval W is defined between two straight lines passing through one end point and perpendicular to the output axis in the projection plane, and the projection of the center of gravity of the circular saw is disposed within the width interval W.

[0017] Advantageous effects of the present application: When viewed in a front projection along the extension direction of the output shaft, the projection of the center of gravity of the circular saw is located between the rear edge of the bottom plate and the output axis, which will not cause an uncomfortable operating feel of the circular saw during operation, so that when the circular saw is operated, the position of the center of gravity is set more reasonably in the length and width directions of the circular saw, and the force applied during the operation of the whole machine is more stable. Brief Description of the Drawings

[0018] Figure 1 is a perspective view of a circular saw according to an embodiment of the present application;

[0019] Figure 2 is a structural view of the circular saw according to an embodiment of the present application in the first state;

[0020] Figure 3 is a structural view of the circular saw according to an embodiment of the present application in the second state;

[0021] Figure 4 is a structural view of another perspective of the circular saw according to an embodiment of the present application, wherein related components of the motor assembly are shown;

[0022] Figure 5 is a partial component structural view of a third perspective of the circular saw according to an embodiment of the present application, removing related components of the cutting member;

[0023] Figure 6 is Figure 5 a partial view of the A-A cross-sectional view in;

[0024] Figure 7 is an exploded view of partial components of the circular saw according to an embodiment of the present application;

[0025] Figure 8 is a half cross-sectional view of the motor assembly and the housing of the circular saw according to an embodiment of the present application;

[0026] Figure 9 is a perspective view of another example of the circular saw according to an embodiment of the present application;

[0027] Figure 10 is a perspective view of a third example of the circular saw according to an embodiment of the present application;

[0028] Figure 11 is a cross-sectional view of the first motor in the motor assembly of the present application;

[0029] Figure 12 is a schematic diagram of the internal structure of the circular saw according to an embodiment of the present application;

[0030] Figure 13 is a schematic diagram of a partial structure of the circular saw according to an embodiment of the present application;

[0031] Figure 14 is Figure 13 a partial cross-sectional view of the structure in;

[0032] Figure 15 is Figure 12 a schematic diagram of another example of a structure different from the structure in;

[0033] Figure 16 is the structural schematic diagram of the third example with a different structure from that in Figure 12 ;

[0034] Figure 17 is the structural schematic diagram of the fourth example with a different structure from that in Figure 12 ;

[0035] Figure 18 is the structural schematic diagram of the fifth example with a different structure from that in Figure 12 ;

[0036] Figure 19 is the structural schematic diagram of the power transmission mechanism of a circular saw in an embodiment of the present application;

[0037] Figure 20 is Figure 19 the structural schematic diagram from another perspective;

[0038] Figure 21 is Figure 20 the schematic diagram of a partial cross-sectional view from another perspective;

[0039] Figure 22 is Figure 20 the structural schematic diagram from another perspective;

[0040] Figure 23 is the structural schematic diagram of the second power transmission mechanism of a circular saw in an embodiment of the present application;

[0041] Figure 24 is the structural schematic diagram of the third power transmission mechanism of a circular saw in an embodiment of the present application;

[0042] Figure 25 is the structural schematic diagram of the fourth motor assembly, power transmission mechanism and housing of a circular saw in an embodiment of the present application;

[0043] Figure 26 is Figure 25 the structural schematic diagram from another perspective of the motor assembly and power transmission mechanism in

[0044] Figure 27 is the schematic diagram of an electrical structure diagram in an embodiment of the present application;

[0045] Figure 28 is the schematic diagram of another electrical structure diagram in an embodiment of the present application;

[0046] Figure 29 is the control flow chart in an embodiment of the present application;

[0047] Figure 30It is another control flow chart of an embodiment in the present application. Detailed implementation manners

[0048] Before explaining any embodiment of the present application in detail, it should be understood that the present application is not limited to the structural details and component arrangements set forth in the following description or shown in the above drawings.

[0049] In the present application, the terms "comprising", "including", "having" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0050] In the present application, the term "and / or" describes the associative relationship of associated objects and indicates that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the present application, the character " / " generally represents an "and / or" relationship between the associated objects before and after.

[0051] In the present application, the terms "connected", "combined", "coupled", "installed" may be direct connection, combination, coupling or installation, or may be indirect connection, combination, coupling or installation. Among them, by way of example, direct connection means that two parts or components are connected together without the need to provide an intermediate member, and indirect connection means that two parts or components are respectively connected to at least one intermediate member, and these two parts or components are connected through the intermediate member. In addition, "connected" and "coupled" are not limited to physical or mechanical connection or coupling, and may include electrical connection or coupling.

[0052] In the present application, those of ordinary skill in the art will understand that relative terms used in connection with a quantity or condition (such as "about", "approximately", "substantially", etc.) are intended to include the stated value and have the meaning indicated by the context. For example, such relative terms include at least the degree of error associated with the measurement of a particular value, tolerances caused by manufacturing, assembly, use, etc. associated with a particular value. Such terms should also be considered to disclose a range defined by the absolute values of two endpoints. The relative term may refer to plus or minus a certain percentage (such as 1%, 5%, 10% or more) of the indicated value. A numerical value that does not employ a relative term should also be disclosed as a particular value having a tolerance. In addition, when expressing a relative angular positional relationship (such as substantially parallel, substantially perpendicular), "substantially" may refer to plus or minus a certain number of degrees (such as 1 degree, 5 degrees, 10 degrees or more) based on the indicated angle.

[0053] In this application, those of ordinary skill in the art will understand that the functions performed by components can be performed by one component, multiple components, one part, or multiple parts. Similarly, the functions performed by parts can also be performed by one part, one component, or a combination of multiple parts.

[0054] In this application, the orientation terms such as "upper", "lower", "left", "right", "front", and "rear" are described based on the orientation and positional relationship shown in the drawings, and should not be construed as limiting the embodiments of this application. In addition, in the context, it should also be understood that when it is mentioned that one element is connected "above" or "below" another element, it can not only be directly connected "above" or "below" another element, but also be indirectly connected "above" or "below" another element through an intermediate element. It should also be understood that the orientation terms such as the upper side, the lower side, the left side, the right side, the front side, and the rear side not only represent the positive orientation, but can also be understood as the side orientation. For example, the lower side can include directly below, lower left, lower right, lower front, and lower rear, etc.

[0055] In this application, the terms "controller", "processor", "central processing unit", "CPU", and "MCU" can be interchanged. When using the units "controller", "processor", "central processing unit", "CPU", or "MCU" to perform specific functions, unless otherwise specified, these functions can be performed by a single one of the above units or multiple ones of the above units.

[0056] In this application, for the terms "device", "module", or "unit" to achieve specific functions, they can be implemented in the form of hardware or software.

[0057] In this application, the terms "calculate", "judge", "control", "determine", "identify", etc. refer to the operations and processes of a computer system or a similar electronic computing device (such as a controller, a processor, etc.).

[0058] To clearly illustrate the technical solution of this application, the upper side and the lower side are defined in the accompanying drawings of the specification.

[0059] As Figure 1 shown is a power tool according to an embodiment of this application. Among them, the power tool includes a motor assembly 20. In this embodiment, the power tool is a circular saw 100. In some embodiments, the power tool can also be other cutting tools, such as a table saw, a miter saw, a marble cutter, a tile saw, a chain saw, etc.

[0060] In some embodiments, the power tool may also be a gardening tool, such as a string trimmer, a blower, a rear-walk power tool such as a lawn mower, a pressure washer, etc. Alternatively, the power tool may also be a decoration tool, such as a screwdriver / drill / wrench type, a rotary hammer, a nail gun, a sander, etc. Alternatively, the power tool may also be, for example, a reciprocating saw, a jigsaw, etc. Alternatively, the power tool may also be other bench-type tools, such as a router, etc. Alternatively, the power tool may also be a grinding tool, such as an angle grinder, a sander, etc. Alternatively, the power tool may also be other power tools, such as a fan, etc. Or a non-road-going walking device, such as a multi-purpose vehicle, may also be an ATV (All Terrain Vehicle), a UTV (Utility Terrain Vehicle), a golf cart, an ATV (All Terrain Vehicle), and may also be an agricultural machinery vehicle, such as a harvester, a spraying vehicle, etc. Of course, it can be understood that for a walking device, it may also be a pressure washer. It may also be an intelligent walking power tool that uses a motor or a motor assembly to drive walking and implement an operation function, such as an intelligent lawn mower, etc.

[0061] It can be understood that as long as it is a power tool driven by a motor, the technical solution disclosed in this embodiment can be adopted, and the power equipment adopting the technical solution disclosed in this embodiment belongs to the scope protected by this application. For example, the power tool may also be a power head, and the power head includes a motor. The power head is used to adapt to some output components to achieve the function of the tool.

[0062] As Figure 1 shown, taking the circular saw 100 as an example. The circular saw 100 is a handheld circular saw. 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. For example, the forward direction of the circular saw 100 is defined as the front, and the direction opposite to the forward direction of the circular saw 100 is the rear.

[0063] The circular saw 100 includes a power supply 31. Among them, in this embodiment, the power supply 31 is a DC power supply. The DC power supply is used to supply electrical energy to the circular saw 100. The DC power supply is a battery pack 31 including at least one energy source for supplying energy to the motor assembly 20. The battery pack 31 cooperates with a corresponding power circuit to supply power to 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 supply power to the corresponding components in the machine through mains power, an AC power supply, and cooperate with corresponding rectification, filtering, and voltage regulation circuits. In the following description, the battery pack 31 will be used to replace the power supply 31, but it should not be regarded as a limitation of the present invention.

[0064] Among them, the battery pack 31 can 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 can be the same or different. In some embodiments, the electrical parameters, structural parameters and physical parameters of the multiple battery packs 31 can be the same or different.

[0065] As Figures 1 to 8 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 base plate 50. Among them, the output shaft 30 is used to mount a cutting member 61. The cutting member 61 rotates about 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 house parts such as the motor assembly 20 and the power transmission mechanism 40, and the output shaft 30 and the cutting member 61 are disposed outside the main body housing 11. The base plate 50 is movably connected to the main body housing 11, and the base plate 50 forms a bottom surface 51 of the base plate that contacts the workpiece. The base plate 50 forms a saw blade through hole 54 extending in the first direction K1, and the saw blade can pass through the saw blade through hole 54 and protrude downward from the bottom surface 51 of the base plate.

[0066] Among them, the main body housing 11 includes a first housing 111, and the first housing 111 forms or is connected to a grip portion 12 for grasping. The grip portion 12 is located at the rear end of the circular saw 100 and can be grasped by a user to operate the circular saw 100 to perform a cutting action. In some embodiments, a control switch 81 and a safety switch 82 are further provided on the grip portion 12, and the control switch 81 can only be triggered when the safety switch 82 is pressed. That is to say, the motor or the motor assembly 20 can only be started after two operations. Thus, the danger caused by a single operation is avoided. When the user grasps the grip portion 12, the hand of the user grasping the grip portion 12 can trigger the safety switch 82 and the control switch 81 to start or stop the circular saw 100. In one embodiment, the first housing 111 may further form a second grip portion 13. The second grip 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 grip portion 13 may also be an external handle mounted on the main body housing 11, that is to say, the second grip portion 13 may be an auxiliary operating member separately mounted on the main body housing 11.

[0067] 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 with 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 inside the fixed guard 62 and can rotate around the output axis 301 to fold into the fixed guard 62. The output shaft 30 extends into the fixed guard 62, and the cutting member 61 is detachably connected to the output shaft 30. In actual work, different types of cutting members 61 can be adopted according to the material of the object to be cut. The cutting member 61 is arranged inside the fixed guard 62, and almost the upper half of its outer circumference is covered by the fixed guard 62. The movable guard 63 rotates inside the fixed guard 62 to block or expose the lower half of the cutting member 61. There is an opening member 64 of the movable guard 63 between the movable guard 63 and the fixed guard 62. When using the circular saw 100, the operator manually pushes the opening member 64 to make the movable guard 63 rotate to expose part of the saw teeth.

[0068] The bottom plate 50 is movably connected to the fixed guard 62. In this embodiment, a connecting seat 52 is provided on the front side of the bottom plate 50, and the connecting seat 52 is connected to the fixed guard 62 by a pin 53 so that the fixed guard 62 can rotate relative to the bottom plate 50. Define the axis where the pin 53 is located as the pivot axis 501. The pivot axis 501 is parallel to the output axis 301. When the fixed guard 62 rotates relative to the bottom plate 50 around the pivot axis 501, the relative position between the fixed guard 62 and the bottom plate 50 will change, resulting in different cutting depths of the circular saw 100. The rotation of the fixed guard 62 is achieved by applying a force on the holding part 12 to make the holding part 12 rotate relative to the bottom plate 50, thereby driving the fixed guard 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.

[0069] As Figure 6 and Figure 8 shown, the motor assembly 20 includes a first motor 21 and a second motor 22. Among them, the first motor 21 includes a first drive shaft 211 that rotates around the first axis 201. The second motor 22 includes a second drive shaft 221 that rotates around the second axis 202. Among them, the first motor 21 and the second motor 22 respectively include a stator and a rotor. Taking the first motor 21 as an example, as Figure 11 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 on the rotor 214 for outputting power. For an outer rotor motor, the rotor is sleeved outside the stator. For an inner rotor motor, the stator is sleeved outside the rotor. In this embodiment, the overall structure of the motor here is generally the same as that of a general brushless motor, and no detailed description will be given here.

[0070] The power transmission mechanism 40 is configured to transmit the power of at least one of the first motor 21 and the second motor 22 to the output shaft 30. The torques of the first drive shaft 211 and the second drive shaft 221 are output through the output shaft 30. In this embodiment, the first motor 21 and the second motor 22 cooperate to output the torque of the motor assembly 30 through the output shaft 30, and output the torque 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 cooperate to drive the cutting member 61 to perform a cutting motion through the output shaft 30. Different from the multi-motor driven power tools in the related art, for example, in outdoor walking devices or wheeled devices, in the related art, multiple motors such as dual motors are used to drive different output shafts or output parts respectively. Exemplarily, in the related art, the first motor and the second motor are used to drive two or more drive wheels or drive shafts respectively. However, in this embodiment, the motor assembly including multiple motors drives the same output shaft, that is to say, the torques of the drive shafts of multiple motors are all output through one output shaft. The end points of the torque transmission paths of multiple motors are the same, which improves the efficient working range of the whole power tool, and enables a power tool with only one output shaft to also use multiple motors for high-efficiency drive. Compared with multiple motors driving different output parts or output shafts, using multiple motors to drive one output shaft in the present application requires more difficulties in the transmission cooperation, power distribution, and drive structure of the motor assembly 20 and the power transmission mechanism 40.

[0071] As Figures 4 to 10 shown, the first motor 21 and the second motor 22 are arranged radially, that is to say, the first drive shaft 211 and the second drive shaft 221 are arranged radially along the radial direction of the first drive shaft 211. Alternatively, the first drive shaft 211 and the second drive shaft 221 are arranged radially along 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 not coincident. In this embodiment, both the first drive shaft 211 and the second drive shaft 221 are 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 perpendicular to each other.

[0072] The main body 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 this embodiment, the shield assembly 60 and the receiving housing 14 are substantially 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 this implementation, the first housing 111 and the receiving housing 14 are connected to each other. A through hole 1111 for the receiving housing 14 to pass through is formed in the right side wall of the first housing 111. Among them, the power transmission mechanism 40 is received in the first housing 111 and outside the receiving housing 14. So as to make the arrangement of the internal components of the main body housing 11 more reasonable.

[0073] The receiving housing 14 includes a first receiving portion 141 for receiving the first motor 21 and a second receiving portion 142 for receiving the second motor 22. As Figure 5 and Figure 8 shown, when observing the orthographic projection along the extending direction of the output shaft, in the direction of the output axis 301, the outer dimension Lc of the projection of the receiving housing 14 along the projection of the first axis 201 and the projection connection direction of the second axis 202 is greater than or equal to 1.1 times the outer diameter D1, D2 of any one motor. When using the first motor 21 and the second motor 22 to cooperate to control 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 both the first motor 21 and the second motor 22 can be stably installed, the size of the receiving housing 14 needs to be greater than 1.1 times the diameter of a single motor. In this way, by reasonably arranging the relative positions of the first motor 21 and the second motor 22, there is space for the first motor 21 and the second motor 22 to be stably installed. On the other hand, it enables users to easily identify the differences between products controlled by one motor and products controlled by the first motor 21 and the second motor 22 simultaneously.

[0074] In this embodiment, taking the second motor 22 as an example, the second motor 22 is an inner rotor motor, and the "outer diameter of the motor" is the outer diameter of the stator of the motor. The outer diameter of the second motor 21 is D2, and the ratio of the outer dimension Lc of the projection of the receiving housing 14 along the projection connection direction of the first axis 201 and 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 receiving housing 14 along the projection connection direction of the first axis 201 and 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 receiving housing 14 along the projection connection direction of the first axis 201 and 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 outer diameters of the first motor 21 and the second motor 22 are the same. In terms of the arrangement position, the first motor 21 and the second motor 22 are arranged separately in the radial direction. In this embodiment, as Figure 6 and Figure 8 shown, in the direction perpendicular to the bottom surface 51 of the bottom plate, there is no overlapping part between the first motor 21 and the second motor 22. In some embodiments, in the extending direction of the cutting member 61, there is no overlapping part between the first motor 21 and the second motor 21, that is to say, there is no straight line extending along the output axis 301 that can pass through the first motor 21 and the second motor 22 at the same time.

[0075] In this embodiment, the first motor 21 and the second motor 22 overlap at least partially in the direction of the output axis 301. That is to say, there is at least a third straight line perpendicular to the output axis 301 that passes through both the first motor 21 and the second motor 22. So that the dimension of the motor assembly 20 in the direction of the output axis 301 is more compact. In this embodiment, the outer dimension Lc of the projection of the receiving housing 14 along the projection connection direction of the first axis 201 and the second axis 202 is greater than the outer dimension H1 of the receiving housing 14 in the direction of the output axis 301, that is, the radial dimension of the receiving housing 14 is greater than the axial dimension of the receiving housing 14.

[0076] As Figure 6 and Figure 8As shown, the first accommodating portion 141 at least supports the first bearing portion 215 of the first motor 21. The first bearing portion 215 is the bearing portion on the side away from the output shaft 30. The first bearing portion 215 includes a ball bearing. The ball bearing supports one end of the first drive shaft 211 away from the output shaft 30. The bottom surface of the first accommodating portion 141 is provided with a first bearing seat 1411 for supporting the ball bearing. The second accommodating portion 142 at least supports the second bearing portion 225 of the second motor 22. The second bearing portion 225 is the bearing portion on the side away from the output shaft 30. The second bearing portion 225 includes a ball bearing. The ball bearing supports one end of the second drive shaft 221 away from the output shaft 30. The bottom surface of the second accommodating portion 142 is provided with a second bearing seat 1421 for supporting the ball bearing. So that the first motor 21 and the second motor 22 are stably mounted by the first accommodating portion 141 and the second accommodating portion 142 respectively.

[0077] In some alternative embodiments, the first motor 21 and the second motor 22 are arranged to partially overlap in the radial direction. That is to say, there is at least a fourth straight line parallel to the output axis 301 that passes through both the first motor 21 and the second motor 22. So that the size of the motor assembly 20 in the radial direction is more compact. Then at this time, the outer dimension Lc of the projection of the accommodating housing 14 along the projection connection direction of the first axis 201 and the second axis 202 can be less than or equal to the outer dimension H1 of the accommodating housing 14 along the output axis 301 direction.

[0078] As Figures 7 to 10 shown, the accommodating housing 14 includes: a first marking structure corresponding to the first motor 21 and a second marking structure corresponding to the second motor 22. The first marking structure and the second marking structure are formed or connected to the outer wall surface of the accommodating housing 14. So that the user can conveniently identify the cooperation drive of the first motor 21 and the second motor 22 in the product. Exposing the internal features of the product and increasing the user's participation in product selection.

[0079] In some embodiments, as Figure 7As shown, the first marking structure 71a is configured to include a shape that is approximately similar to the partial contour of the first motor 21. The second marking structure 72a is configured to include a shape that is approximately similar to the partial contour of the second motor 22. For example, the first marking structure 71a is the first receiving portion 141 in the receiving housing 14, and the outer wall of the first receiving portion 141 is an arc edge that is similar to the outer shape of the first motor 21. The second marking structure 72a is the second receiving portion 142 in the receiving housing 14, and the outer wall of the second receiving portion 142 is an arc edge that is similar to the outer shape of the second motor 22. Or, for example, the first marking structure 71a is the first receiving portion 141 in the receiving housing 14, and the second marking structure 72a is the second receiving portion 142 in the receiving housing 14. There are obvious depressions, or protrusions, or distinguishable shapes, or separation marks, etc. between the first receiving portion 141 and the second receiving portion 142, which divide the receiving housing 14 into partitions associated with the number of motors. It can be understood that the outer wall of the first receiving portion 141 can be designed with other shapes from the perspective of industrial design, and the outer wall of the second receiving portion 142 can be designed with other shapes from the perspective of industrial design, but in the eyes of the technical field and ordinary consumers, its shape can be recognized as a motor and can be understood as a shape similar to the motor contour. For example, in addition to the circular shape identical to the motor shape, shapes formed by the cooperation of ellipses, arcs and straight lines, multiple arcs, rectangles, polygons, triangles and other shaping lines.

[0080] In this embodiment, the outer walls of the first marking structure 71a and the second marking structure 72a are configured as a continuous surface. As Figure 7 shown, the outer walls of the first receiving portion 141 and the second receiving portion 142 are a continuous structure, that is, the receiving housing 14 is an integral structure.

[0081] In some alternative embodiments, the first marking structure and the second marking structure are configured as independent double-barrel structures. It can be that the receiving housing 14 is an integral structure, and the first marking structure and the second marking structure are respectively two closed structures provided on the outer wall of the receiving housing 14. It can also be that the receiving housing 14 is divided into a structure enclosed by two independent outer walls of the first receiving portion 141 and the second receiving portion 142.

[0082] In some alternative embodiments, such as Figure 7As shown, the first marking structure 71b and the second marking structure 72b are additional line structures provided on the outer walls of the first receiving portion 141 and the second receiving portion 142. For example, the first marking structure 71b is a line structure on the outer wall of the first receiving 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 receiving portion 142 that is similar to the outline of the motor. The line structure can be a protruding line, an inlaid line, a concave line, or a hollowed-out line. For example, the first marking structure 71b is a line structure on the outer wall of the first receiving portion 141 that is associated with indicating the motor or the number of motors. The second marking structure 72b is a line structure on the outer wall of the second receiving portion 142 that is associated with indicating the motor or the number of motors, such as those related to and similar to "characters", "letters", "numbers", where "indicating the motor" is a line structure that can be recognized as a motor in the technical field and by ordinary consumers.

[0083] In some alternative embodiments, such as Figure 9 and Figure 10 As shown, the first marking structure includes first display portions 71c, 71d, the second marking structure includes second display portions 72c, 72d, and the first display portions 71c, 71d and the second display portions 72c, 72d of the second marking structure are respectively arranged at easily visible positions on the main body housing 11. So that when the user is using the circular saw 100, they can confirm the usage status of the first motor 21 and the second motor 22 by using the display portions just by moving their line of sight.

[0084] In some embodiments, such as Figure 9 As shown, the first display portion 71c includes a light-emitting body, and the light-emitting body at least indicates the on and off states of the first motor 21. For example, the first display portion 71c includes a light-emitting diode (LED) lamp, a COB (Chip On Board) lamp bead, or an incandescent lamp, etc. The first display portion 71c is arranged on the upper surface of the first housing 111, and the first display portion 71c is arranged on the upper surface portion of the first housing 111 close to the receiving housing 14. In some embodiments, the first display portion 71c is arranged on the upper surface of the receiving housing 14. Among them, the first display portion 71c indicates the on and off states of the first motor 21 through changes in the display, such as through lighting and extinguishing, constant lighting and flashing, different color and other different indicative features. The first display portion 71c can also be multiple lamps or lamp strips. Different display features of different numbers or sections of lamps are used to indicate the rotation speed range of the first motor 21. In some embodiments, the first display portion 71c can also indicate an abnormality as an abnormality alarm.

[0085] In some alternative embodiments, such as Figure 10As shown, the first display unit 71d includes a display screen, which serves as a human-machine interaction interface to display the operating state 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) or an Organic Electroluminescence Display (OLED) display screen. The first display unit 71d is disposed on the upper surface of the housing 14. In some embodiments, the first display unit 71d is disposed on the upper surface of the first housing 111, and the first display unit 71d is disposed on the upper surface portion of the first housing 111 close to the housing 14. Since the display screen serves as a human-machine interaction interface, the displayed content is more detailed, finer and more intuitive. Therefore, according to different settings, various information of the first motor 21 during operation can be displayed on the display screen. For example, on-off information, speed information, output torque information, forward and reverse rotation information, loss information, temperature information, and even the first motor 21 can be intuitively displayed in the form of a dynamic model on the display screen.

[0086] In some embodiments, the first display unit may include a light-emitting body and a display screen at the same time. The second display unit 72c includes at least one of a light-emitting body or a display screen and is used to indicate the operating state of the second motor 22. That is to say, the first display units 71c and 71d and the second display unit 72c may be of the same type of display component or different types of display components. At the same time, for the convenience of the user to observe, the first display units 71c and 71d and the second display unit 72c are disposed in the same position area. For example, they are all disposed on the upper part of the housing 14, one 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 component, the first display unit and the second display unit can be integrated. For example, different brightnesses and different colors of LED lights are used to display different motor startup combinations. 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 show the information of the first motor 21 and the second motor 22 respectively, or the information of the first motor 21, the second motor 22 or the first motor 21 and the second motor 22 can be selected by the user through a menu.

[0087] In some embodiments, the first display unit 71e includes an icon representing the first motor 21, and the second display unit 72e includes an icon representing the second motor 22. The first display unit 71e and the second display unit 72e are respectively provided with an adhesive layer. That is to say, the first display unit 71e and the second display unit 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 unit 71e and the second display unit 72e can be arranged on the same paper with an adhesive layer.

[0088] In the technical solutions of the above embodiments, a part of them can be used alone, or a combination of several of them can be used, so as to set the specific implementation manners of the first marking structure and the second marking structure according to the needs of the actual power tool.

[0089] As 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 torques of the first drive shaft 211 and the second drive shaft 221 are output through the output shaft 30. The power transmission mechanism 40 includes: a transmission assembly 41 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 speed reduction mechanism. A clutch assembly 42 is configured between the first motor 21 and the second motor 22. 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 intervals where their 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 at least partially overlaps with any one of the first motor 21 and the second motor 22 in the axial direction of the drive shaft, or at least partially overlaps 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 the connection relationship, the clutch assembly 42 is directly or indirectly connected to the first motor 21 and the second motor 22 respectively, or there is a direct or indirect power transmission path.

[0090] Setting the transmission assembly 41 with speed reduction and distance increase improves the cutting ability of the circular saw 100 and makes the cutting efficiency of the circular saw 100 high. The coupling of the motor assembly 20 enables the circular saw 100 to be commonly used in light load conditions and high load conditions. At the same time, the performance requirements for the motors in the motor assembly are reduced, and thus small-diameter motors can be used to achieve the performance requirements of large motors. This can not only reduce costs, but also reduce the requirements for aspects such as machine heat dissipation.

[0091] 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. As Figures 19 to 21 shown, in one 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 further includes a second gear set 41b connecting the second drive shaft 221 and the output shaft 30, wherein the clutch assembly 42 is disposed 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 single-stage reduction transmission, that is to say, the first gear set 41a provides a single reduction motion. The second gear set 41b is a single-stage reduction transmission, that is to say, the second gear set 41b provides a single reduction motion. In some alternative embodiments, the first gear set 41a and the second gear set 41b may also include multi-stage reduction transmissions, 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 one set of gear sets can provide multiple transmission ratios or reduction ratios. In this embodiment, the reduction ratio of the first gear set 41a is different from the reduction ratio of the second gear set 41b. The first gear set 41a and the second gear set 41b respectively include one or several combinations of cylindrical gear transmission, bevel gear transmission, worm transmission, and planetary gear transmission.

[0092] 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 drive shaft 211. Optionally, the first driving gear 411 is formed at one end of the first drive shaft 211 close to the cutting member 61. Wherein, 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.

[0093] The second gear set 41b includes a second driving gear 413 and a second driven gear 414. The second driving gear 413 is formed on 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. Wherein, 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 but does not coincide with the first axis 201. The second driving gear 413 and the second driven gear 414 form a speed-reducing 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 rotations of the first motor 21 and the second motor 22 in the first rotation direction, and the one-way transmission member 421 disengages the rotations of the first motor 21 and the second motor 22 in the 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 with a third gear 422. Wherein, the third gear 422 is externally meshed with the first driven gear 412 to couple between the first motor 21 and the second motor 22. Further, 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 substantially in an isokinetic transmission, that is, the rotational speed of the third gear 422 is the same as the rotational 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.

[0094] During operation, when the first motor 21 starts to operate, the first motor 21 drives the output shaft 30 to rotate through the first gear set 41a. Due to the setting of the one-way transmission member 421, the output speed of the first motor 21 is restricted from being transmitted to the second motor 22, that is, the one-way transmission member 421 only allows the rotation to be transmitted from the second drive shaft 221 (the second driving wheel) of the second motor 22 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 operate, the rotational locking of the one-way transmission member 421 is released. When the rotational speed of the second driven gear 414 is less than that of the third gear 422, the rotational speed of the second driven gear 414 cannot be transmitted to the output shaft. It can be understood that when the rotational speed of the power output part (the outer ring in this embodiment) of the one-way clutch is faster than that of the power source (the inner ring in this embodiment), the one-way clutch is in a disengaged state, and there is no interlocking relationship between the inner ring and the outer ring, that is to say, the one-way overrunning function of the one-way clutch. When the rotational speed of the second driven gear 414 is equal to or higher than the rotational speed of the first driven gear 412, that is, when the rotational speed of the second driven gear 414 is equal to or higher than the rotational speed of the third gear 422, the inner and outer rings of the one-way clutch are interlocked, 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 rotational speed of the second driven gear 414 (i.e., the idler shaft 415).

[0095] A non-thrust bearing 416 is provided at the first end of the idler shaft 415, and an elastic member 417 is provided at one end of the non-thrust bearing 416. To prevent the gears on the idler shaft 415 from moving axially.

[0096] In some embodiments, the clutch assembly further includes other mechanical clutch assemblies. For example, jaw clutches, ratchet clutches, centrifugal clutches, differentials, friction clutches, and hydraulic clutches. The above mechanical clutches can be used as the clutch assembly of the present application after simple deformation or combination. On 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 substantial content of the present application.

[0097] In some embodiments, the clutch assembly further includes an electronic clutch. For example, 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, and a slip-ring electromagnetic clutch.

[0098] In some embodiments, the mechanical clutch assembly and the electronic clutch can be coupled simultaneously to restrict 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.

[0099] Such as Figure 15As shown, 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. This makes the part of the motor assembly located on the upper side of the output shaft larger, and such a setting can ensure the cutting depth of the circular saw. The output axis 301 is basically the central position of the cutting member 61, and the cutting depth of the circular saw is closely related to the position relationship between the output axis and the bottom plate. Setting the driving axis of the motor assembly above the output axis does not affect the installation and use of the bottom plate of the circular saw, and during the cutting depth process of the circular saw, there will be no interference with the components near the bottom plate of the output axis. The included angle α between the connection line of the first axis 201 and the output axis 301 and the connection line of the second axis 202 and the output axis 301 is greater than or equal to 45° and less than or equal to 180°. This is to ensure the transmission setting between the first motor and the second motor, and on the other hand, it also makes the layout structure of the first motor and the second motor and the output shaft compact.

[0100] Optionally, when the first motor 21 and the second motor 22 are arranged radially, they are staggered in the up and down directions. 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 motor with a small torque output, and the second motor 22 is a motor with a large torque output. At least one of the gear assemblies in the first gear set 41a and the second gear set 41b includes a helical gear.

[0101] As Figure 16 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 basically flush in the up and down directions. The output shaft 30 and the idler shaft 415e are respectively located on the same side of the first drive shaft 211e.

[0102] As Figure 17 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 gear 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 first motor and the second motor output torque synchronously or substantially synchronously. 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. The included angle α between the connection line of the first axis and the output axis and the connection line of the second axis and the output axis is greater than or equal to 45° and less than or equal to 180°.

[0103] As Figures 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 and the second drive shaft 221g of the second motor 22g are coaxially arranged. The first drive shaft 211g and the second drive shaft 221g are mechanically coupled. The first driving gear 411g on the first drive shaft 211g. The first driving gear 411g is externally meshed with the driven gear 412g on the output shaft 30g. The first driving gear 411g and the driven gear 412g are for speed reduction transmission.

[0104] The housing 14g is used to house the first motor 21g and the second motor 22g. Optionally, the first housing portion 141g for housing the first motor 21g and the second housing portion 142g for housing the second motor 22g of the housing 14g are arranged axially. Wherein, the outer dimension Lc' of the housing 14g in the direction of the first drive shaft 211g or the second drive shaft 221g and the length of any one of the first drive shaft 211g and the second drive shaft 221g The ratio 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 both the first motor 21g and the second motor 22g can be stably installed, the size of the housing 14g needs to be greater than 1.1 times the length of a single drive shaft. In this way, by reasonably arranging the relative positions of the first motor 21g and the second motor 22g, there is space for the first motor 21g and the second motor 22g to be stably installed. In some embodiments, the outer dimension Lc' of the housing 14g in the direction of the first drive shaft 211g or the second drive shaft 221g and the length of any one of the first drive shaft 211g and the second drive shaft 221g The ratio is greater than or equal to 1.2, 1.4, 1.6, 1.8. In some embodiments, the outer dimension Lc' of the housing 14g in the direction of the first drive shaft 211g or the second drive shaft 221g and the length of any one of the first drive shaft 211g and the second drive shaft 221g The ratio is greater than or equal to 2. In some embodiments, the outer dimension Lc' of the housing 14g in the direction of the first drive shaft 211g or the second drive shaft 221g and the length of any one of the first drive shaft 211g and the second drive shaft 221g The ratio is greater than or equal to 2.1, 2.2.

[0105] As Figure 19 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.

[0106] 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 of an integrally formed structure. In some implementations, the first drive shaft 211g and the second drive shaft 221g can be separately provided independent shafts, and the first drive shaft and the second drive shaft are connected by a connecting member or a fastener to achieve the effect of synchronous rotation. Among them, there is also a motor fixing part 24g for connecting to the first stator 212g and the second stator 222g respectively. The motor fixing part 24g is provided with a receiving channel 241g, and the receiving channel 241g is used for receiving at least part of the first drive shaft 211g and the second drive shaft 221g. The receiving channel 241g overlaps at least part of the first stator 212g along the first axis 201 direction, and the receiving channel 241g overlaps at least part of the second stator 222g along the first axis 201 direction. The stator 212 of the first motor and the stator 222 of the second motor are coaxially connected through the motor fixing part 24g.

[0107] In some alternative embodiments, a clutch assembly is provided between the first motor shaft and the second motor shaft, or between the first motor and the output shaft, or 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. Among them, the clutch assembly can be any one of the clutch structures in the above embodiments. The clutch assembly is provided in the motor fixing part, or between the first driving gear 411g and the first driven wheel. At this time, along the output axis 301 direction, 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.

[0108] In the present application, the first motor 21 outputs a first torque and a first rotational speed. The second motor 22 outputs a second torque and a second rotational speed. In some embodiments, the first torque is different from the second torque. The first rotational speed and the second rotational speed are different. It should be explained that the difference between the first torque and the second torque means that, in some embodiments, the maximum output torques of the first motor 21 and the second motor 22 are different, but there will be a moment or a period during the entire working process of the first motor 21 and the second motor 22 when the output torques are the same. In some embodiments, it means that the output torque ranges of the first motor 21 and the second motor 22 in the high-efficiency range are different, but there will be a moment or a period during the entire working process of the first motor 21 and the second motor 22 when the output torques are the same. The first rotational speed and the second rotational speed are different. In some embodiments, it means that the maximum output rotational speeds of the first motor 21 and the second motor 22 are different, but there will be a moment or a period during the entire working process of the first motor 21 and the second motor 22 when the output rotational speeds are the same. In some embodiments, it means that the output rotational speed ranges of the first motor 21 and the second motor 22 in the high-efficiency range are different, but there will be a moment or a period during the entire working process of the first motor 21 and the second motor 22 when the output rotational speeds are the same.

[0109] In some embodiments, taking the first motor 21 and the second motor 22 as an example, 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. Or, the first motor 21 and the second motor 22 are of the same type of motor, but their output rotational speeds and output torques are different. In this embodiment, both the first motor 21 and the second motor 22 are DC brushless motors.

[0110] Meanwhile, 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 stack length of the motor. Here, it needs to be explained that the "outer diameter of the motor" is the overall outer diameter of the motor, and the "stack length of the motor" is the length of the stator core. In this embodiment, the motor diameter of the first motor 21 is less than or equal to 75 mm, less than or equal to 70 mm, and less than or equal to 65 mm. In some embodiments, the motor diameter of the first motor 21 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, 55 mm. In this embodiment, the motor diameter of the second motor 22 is less than or equal to 75 mm, less than or equal to 70 mm, and less than or equal to 65 mm. 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, 55 mm.

[0111] In some embodiments, the structural parameters of the first motor 21 and the second motor 22 include the outer diameter of the stator core, the inner diameter of the stator core, the outer diameter of the rotor core, the inner diameter of the rotor core, the thickness of the rotor magnetic pole, the thickness of the stator magnetic pole, the air gap length, the core length, the number of stator pole pairs, the corresponding radian of the stator magnetic pole, the number of rotor pole pairs, and the corresponding radian of the rotor magnetic pole. At least one of the structural parameters of the first motor 21 and the second motor 22 is different.

[0112] Of course, in some embodiments, the first motor 21 and the second motor 22 can be two completely identical motors, achieving a higher efficiency range through mutual coupling.

[0113] 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 circuit to supply power to the first motor 21 and the second motor 22. As Figure 5 and Figure 7 shown, a semi-open battery accommodation chamber 15 is formed by inward depression on the main body housing 11. The battery accommodation chamber 15 is disposed between the holding portion 12 and the motor assembly 20. The battery accommodation chamber 15 and the motor assembly 20 are disposed on the same side of the first housing 111. The battery accommodation chamber 15 and the battery pack 31 are disposed in front of the holding portion 12. The battery accommodation chamber 15 is disposed on the first housing 111.

[0114] As Figure 20As shown, the battery accommodation chamber 15 includes a coupling portion 1511 electrically connected to the battery pack 31, and tool terminals (not shown in the figure) are provided on the coupling portion 1511. Tool terminals with the same structure are provided on different power tools (not shown in the figure). The battery pack 31 includes: a plug-in structure and a terminal interface. The tool terminals are adapted to the terminal interface on the battery pack 31. Tool terminals with the same structure are provided on different power tools so that the battery pack 31 can supply power to a variety of different power tools. The power circuit cooperating therewith is adjusted according to the control requirements of different power tools. In some embodiments, the nominal voltage of the power tool is greater than or equal to 18V. The nominal voltage of the power tool is greater than or equal to 36V and less than or equal to 56V. In some embodiments, the nominal voltage of the power 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 holding portion 12 are arranged on the same side of the cutting member 61, and after the battery pack 31 is inserted into the battery chamber 15 and at least partially arranged behind the first motor and the second motor, at least part of the battery pack 31 is arranged in front of the holding portion 12. Optionally, the battery pack 31 is inserted into the battery chamber 15 obliquely. In some embodiments, part of the battery pack 31 is located above the first motor and the second motor.

[0115] As Figure 20 shown, the circular saw 100 further includes a controller 17 for controlling the motor assembly 20. The controller 17 is arranged on the 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 employs a dedicated control chip, for example, a single-chip microcomputer, a micro control module MCU (Microcontroller Unit). It should be noted that the control chip can be integrated within the controller 17, or can also be arranged independently of the controller 17. Regarding the structural relationship between the drive chip and the controller 17, this embodiment does not limit.

[0116] As Figure 6 and Figure 8 shown, the motor assembly 20 further includes: a first fan 216 supported by the first drive shaft 211, and the first fan 216 is driven by the first motor 21 to rotate to generate a cooling air flow. A second fan 226 supported by the second drive shaft 221, and the second fan 226 is driven by the second motor 22 to rotate to generate a cooling air flow. As Figures 21 to 22As shown, an air flow port is formed on the main body housing 11. When either the first fan 216 or the second fan 226 rotates, a heat dissipation air flow path can be generated, and the heat dissipation air flow path flows through at least the control circuit board 18 and the motor assembly 20. The brushless motor has a higher output power than the brushed motor. However, 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 for controlling the power supply of the motor will also increase. Therefore, it is necessary to dissipate heat from the control circuit board 18 sufficiently. In some embodiments, when the first motor and the second motor are coaxially arranged, only the first fan can be supported by at least one of the first drive shaft, the second drive shaft, or the output shaft. When either the first motor or the second motor rotates, the first fan rotates and generates a heat dissipation air flow path.

[0117] The air flow port includes a first air inlet 161 and a first air outlet 162. The heat dissipation air flow enters the main body housing 11 from the first air inlet 161 and flows out of the main body housing 11 from the first air outlet 162. The control circuit board 18 is disposed in the first housing 111. The first air inlet 161 allows the heat dissipation air flow to enter the receiving housing 14 from the first housing 111. When any one of the motors in the motor assembly 20 starts, the corresponding fan rotates synchronously to generate a heat dissipation air flow. So that the heat dissipation air flow can at least flow through the control circuit board 18 and the motor assembly 20. That is to say, at least one of the control circuit board 18 and the motor assembly 20 needs to be disposed in the flow path of the heat dissipation air flow. In this way, when any one of the motors in the motor assembly 20 starts and the fan rotates, external air can flow into the interior of the circular saw 100 through the air inlet, forming a heat dissipation air flow; and during the process of flowing towards the fan, the heat dissipation air flow flows through at least any one of the circuit board and the motors in the motor assembly 20, and finally flows out through the air outlet.

[0118] As Figures 20 to 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.

[0119] 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.

[0120] Since the first fan 216 and the second fan 226 are basically located in the receiving housing 14, a first communication port 146 and a second communication port 147 are provided on the upper part of the receiving housing 14 corresponding to the first fan 216 and the second fan 226 respectively. In some embodiments, the installation 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 either. Ensure that by effectively utilizing the negative pressure generated by the rotation of the fan, a cooling air flow flowing through the control circuit board 18 and entering from the first air inlet 161 is generated.

[0121] The air flow port further includes a first air outlet 162 for allowing the heat dissipation air flow to flow out of the main body housing 11. The first air outlet 162 communicates the receiving housing 14 and the first housing 111 with the external environment. In the present embodiment, the air outlet direction of the first air outlet 162 faces the front side of the circular saw 100. Optionally, the second motor 22 is disposed closer to the front than the first motor 21. In some embodiments, air flow guiding ribs are provided in the first housing 111 for guiding the heat dissipation air flow so that the heat dissipation air flow flows in the defined space of the air flow guiding ribs.

[0122] 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 normally triggered, at least the first motor 21 starts, 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 external air into the interior of the circular saw 100 for heat dissipation. After the fan rotates, the heat dissipation air flow 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 out from the first communication port 146 through the first motor 21 and the second motor 22 and out through the first air outlet 162.

[0123] In this embodiment, a second air outlet 163 is further included. The air outlet directions of the second air outlet 163 and the first air outlet 162 are different. In this embodiment, the second air outlet 163 is disposed near the second motor 22, and the second air outlet 163 blows air in a direction away from the cutting member 61. Thus, in addition to the heat dissipation function, the heat dissipation air flow of the second air outlet 163 also has a dust blowing function. The dust and debris generated during the cutting process can be blown away. Optionally, the second air outlet 163 includes a third communication port 164 for communicating the receiving housing 14, the first housing 111, and the outside, and a fourth communication port 165 disposed on the side wall of the bottom plate 50 for also serving 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. 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 operating, the heat dissipation air flow enters from the first air inlet 161, flows through the control circuit board 18 and the motor assembly 20, and 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 operating, the heat dissipation air flow enters from the first air inlet 161, flows through the control circuit board 18 and the motor assembly 20, and most of it flows out from the second air outlet 163.

[0124] In this embodiment, the number of the circuit board housings 19 is one, the number of the controllers 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 provided on one control circuit board 18. The circuit board housing 19 can accommodate at least one control circuit board 18. The multiple controllers are communicatively or electrically connected to each other.

[0125] As Figure 23 shown, as an optional embodiment, the number of the circuit board housings 19 is two, and the number of the control circuit boards 18 is at least two. Using multiple control circuit boards 18 to configure multiple controllers can reduce the requirement for the capabilities of the control circuit boards 18. The circuit board housings 19 are all placed radially outside the first fan and the second fan. Optionally, the circuit board housings 19 and the control circuit boards 18 are disposed 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. The structures of the first circuit board housing 19a and the second circuit board housing 19b 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 specific positions where the first circuit board housing 19a and the second circuit board housing 19b are located.

[0126] As Figure 24As shown, as an alternative embodiment, the second plane S2 of the circuit board 18 is spatially perpendicular to the third plane S3. 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. Heat conduction occurs between the control circuit board 18 and the fixed shield. In this embodiment, the circuit board housing 19 is in close contact with the fixed shield so that the heat of the circuit board housing 19 can be radiated through the surface of the fixed shield, increasing the heat dissipation path of the control circuit board 18.

[0127] As Figure 25 shown, it is the second embodiment of the heat dissipation solution. The control circuit board 18 is disposed between the motor assembly 20 and the battery pack 31. Optionally, the control circuit board 18 is disposed in the first housing 111 and is located between the storage housing and the battery accommodation chamber 15. In the direction perpendicular to the extension direction 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.

[0128] Among them, 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 disposed radially outside the first fan 216 and the second fan 226. Optionally, the circuit board housing 19 and the control circuit board 18 are disposed radially behind the first fan 216 and the second fan 226, between the battery accommodation chamber 15 and the housing 14. The second air inlet 166 is disposed in the battery accommodation chamber 15. In this embodiment, as Figure 7 shown, the battery accommodation chamber 15 includes at least a first outlet 151 for the battery pack 31 to enter and exit the battery accommodation chamber 15, and a second outlet 152 different from the first outlet 151. As Figure 7 and Figure 25 shown, the second air inlet 166 includes the first outlet 151, the second outlet 152, and a fifth communication port 167 that communicates the battery accommodation chamber 15 and the first housing 111. It can be understood that the fifth communication port 167 is an air flow port for the heat dissipation air flow to flow out of the battery accommodation chamber 15. In order to make the heat dissipation of the heat dissipation air flow more sufficient, the fifth communication port 167 is disposed above the first fan 216 and the second fan 226, and the fifth communication port 167 is disposed at least below the first outlet 151.

[0129] As Figure 7As shown, since the first fan 216 and the second fan 226 are basically located in the receiving housing 14, a first communication port 146 and a second communication port 147 are provided on the upper part of the receiving housing 14 corresponding to the first fan 216 and the second fan 226 respectively. In some embodiments, the installation 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 either. Ensure that by effectively utilizing the negative pressure generated by the rotation of the fan, a cooling air flow flowing through the battery pack 31 and the control circuit board 18 and entering from the second air inlet 166 is generated.

[0130] As Figure 7 and Figure 25 shown, the air flow port further includes a first air outlet 162 for the heat dissipation air flow to flow out of the main body housing 11. The first air outlet 162 communicates 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 faces the front side of the circular saw 100. Optionally, the second motor 22 is arranged closer to the front than the first motor 21. In some embodiments, air flow guiding ribs are arranged in the first housing 111 to give a guidance to the heat dissipation air flow so that the heat dissipation air flow flows in the defined space of the air flow guiding ribs.

[0131] During the cutting operation, in the state where the bottom surface 51 of the base 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 external air into the interior of the circular saw 100 for heat dissipation. After the fan rotates, the heat dissipation air flow enters the battery accommodation chamber 15 and the interior of the first housing 111 from the second air inlet, flows through the battery pack 31, the circuit board housing 19 and the control circuit board 18, and flows out from the first communication port 146 through the first motor 21 and the second motor 22, and out from the first air outlet 162.

[0132] In this embodiment, a second air outlet 163 is further included. The air outlet directions of the second air outlet 163 and the first air outlet 162 are different. In this embodiment, the second air outlet 163 is arranged at a position close to the second motor 22, and the second air outlet 163 blows air in a direction away from the saw blade. Furthermore, in addition to the heat dissipation function, the heat dissipation air flow of the second air outlet 163 also has a dust blowing function. The dust and debris generated during the cutting process can be blown away. Optionally, the second air outlet 163 includes a third communication port 164 for communicating the receiving housing 14, the first housing 111 and the outside, and a fourth communication port 165 arranged on the side wall of the base plate 50 for taking into account the dust blowing function. As Figure 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 operating, the heat dissipation air flow enters from the second air inlet 166, flows through the battery pack 31, the control circuit board 18, and the motor assembly 20, and 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 operating, the heat dissipation air flow enters from the second air inlet 166, flows through the battery pack 31, the control circuit board 18, and the motor assembly 20, and most of it flows out from the second air outlet 163.

[0133] In some embodiments, the circular saw 100 is provided with a first air inlet 161 and a second air inlet 166 simultaneously, so as to make the heat dissipation of the control circuit board 18 and the motor assembly 20 more sufficient.

[0134] In this embodiment, the number of the circuit board housings 19 is one, the number of the controllers 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 communicatively or electrically connected to each other.

[0135] As Figure 26 shown, as an alternative embodiment, the number of the circuit board housings 19 is two, and the number of the control circuit boards 18 is at least two. Using multiple control circuit boards 18 to configure multiple controllers can reduce the requirement for the capabilities of the control circuit board 18. The circuit board housings 19 and the control circuit boards 18 are arranged radially outside the first fan 216 and the second fan 226. Optionally, the circuit board housings 19 and the control circuit boards 18 are arranged rearward radially of the first fan 216 and the second fan 226, between the battery accommodation chamber 15 and the housing 14. Wherein, the circuit board housing 19 includes a first circuit board housing 19a and a second circuit board housing 19b. The structures of the first circuit board housing 19a and the second circuit board housing 19b can be the same to increase versatility, or can 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 specific positions where the first circuit board housing 19a and the second circuit board housing 19b are located.

[0136] As Figures 1 to 5 shown, the cutting member 61 is a circular saw blade of the circular saw 100 with an outer diameter greater than 6 inches in this embodiment. In some embodiments, the circular saw blade of the circular saw 100 has an outer diameter range of approximately 6 inches to 12 inches. As Figure 2 and Figure 3 shown, when observed in the orthographic projection along the extending direction of the output shaft, the projection of the center of gravity G of the circular saw 100 is located between the rear edge of the bottom plate 50 and the output axis 301. Optionally, as Figure 2As shown, it is the first state of the circular saw 100. At this time, the fixed guard 62 rotates relative to the base plate 50 about the pivot axis 501 to the minimum angle. 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 to the distance L2 from the rear edge of the base plate 50 to the output axis 301 is less than or equal to 1. When the circular saw 100 uses the first motor and the second motor to drive the output shaft in cooperation, the working efficiency of the circular saw is improved and the cutting ability is improved. However, at the same time, the weight of the motor assembly will be heavier than that of a circular saw using 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 during operation, so that the circular saw is not easy to shake during operation and is more stable to use.

[0137] 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 to the distance L2 from the rear edge of the base plate 50 to 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 always located behind the output axis 301, that is, on the side of the output axis 301 close to the holding portion 12. As Figure 3 As shown, it is the second state of the circular saw 100. At this time, when the fixed guard 62 rotates relative to the base plate 50 about the pivot axis 501 to the maximum angle, the distance L1' from the center of gravity of the circular saw 100 to the output axis 301 is the smallest.

[0138] As Figure 4As shown, the cutting member 61 extends within a cutting plane S4, and the holding portion 12 is substantially symmetrically arranged with respect to the first plane S1. In the direction perpendicular to the bottom surface 51 of the base plate, the projections of the first drive shaft 201 and the second drive shaft 202 have two end points that are the farthest apart in the direction of the output axis 301. A width interval W is defined between two straight lines that respectively pass through one end point and are perpendicular to the output axis 301 on the projection plane, and the projection of the center of gravity G of the circular saw is arranged within the width interval W. In an embodiment, when 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 end point closest to the cutting member and a second end point farthest from the cutting member. The first end point and the second end point are the extreme end points in the left-right direction of the circular saw when the first drive shaft and the second drive shaft are regarded as a whole. 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 define a width interval W, that is, the width interval W is the position interval of the whole machine within this width. The width interval in the front-back direction of the circular saw is not only the front-back range of the motor assembly, but the front-back range of the whole circular saw. In an embodiment, when the first motor and the second motor are arranged radially and the first drive shaft and the second drive shaft intersect. 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 end point closest to the cutting member and a second end point farthest from the cutting member. The first end point and the second end point are the extreme end points in the left-right direction of the circular saw when the first drive shaft and the second drive shaft are regarded as a whole. 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 define a width interval W, that is, the width interval W is the position interval of the whole machine within this width. The width interval in the front-back direction of the circular saw is not only the front-back range of the motor assembly, but the front-back range of the whole circular saw.

[0139] In an embodiment, when the first motor and the second motor are arranged coaxially, 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 end point closest to the cutting member and a second end point farthest from the cutting member. The first drive shaft and the second drive shaft are arranged left and right in the left-right direction of the circular saw. Therefore, 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 define a width interval W, that is, the width interval W is the position interval of the whole machine within this width. The width interval in the front-back direction of the circular saw is not only the front-back range of the motor assembly, but the front-back range of the whole circular saw.

[0140] When the circular saw 100 uses the first motor and the second motor to jointly drive the output shaft to move, the working efficiency of the circular saw is improved, and the cutting ability is improved. However, at the same time, the weight of the motor assembly will be heavier than that of a circular saw using a single motor. Reasonably set the position of the center of gravity G of the circular saw, so that the circular saw with the first motor and the second motor will not cause a bad operating feel of the circular saw 100 during operation. When the circular saw is operating, in the width direction, the center of gravity is set within the width range of the first motor and the second motor, and the force applied to the whole machine during operation is more stable.

[0141] 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 does not exceed the cutting plane S4 on the left side. 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 and the first plane S1 to 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 preferably arranged on the first plane S1, and it will not 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 side or the right side of the first plane S1.

[0142] The bottom plate 50 is formed with a hole extending along the first direction K1 to enable the cutting member 61 to pass through the bottom plate 50. As Figure 5 shown, along the first direction K1, the ratio of the outer edge dimension L3 of the receiving housing 14 to the outer edge dimension La of the main housing 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 housing 14 may be the same as the outer dimension Lc of the receiving housing 14 along the perpendicular direction of the first drive shaft 211 and the second drive shaft 221.

[0143] As Figure 4 and Figure 8 shown, along the output axis 301 direction, the ratio of the outer edge dimension H1 of the receiving housing 14 to the outer edge dimension Ha of the main housing 11 is greater than or equal to 0.15 and less than or equal to 0.4.

[0144] As Figure 27 shown, the controller 17 is used to control the motor assembly 20. The controller 17 is configured to determine the start states of the first motor 21 and the second motor 22 according to preset conditions.

[0145] As an embodiment, the controller includes a first controller 171 and a second controller 172, namely 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 serially communication-connected, but also have relatively independent control modules.

[0146] 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 having two independent control circuits to control the first motor 21 and the second motor 22. Among them, the electrical characteristic parameters may also include parameters such as bus current, freewheeling time, and demagnetization time.

[0147] In this embodiment, the first motor 21 and the second motor 22 are respectively three-phase brushless motors. It includes three-phase stator windings U, V, and W that are commutated electronically. 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 delta-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 the current from the battery pack 31 to the stator windings U, V, and W to drive the motor to rotate.

[0148] As Figure 29 shown, the specific control flow is as follows:

[0149] S210: The control switch 81 is activated.

[0150] During operation, the first controller 171 detects that the control switch 81 is activated, that is, it receives a start signal.

[0151] S220: The first motor meets the starting condition. If so, execute S240; if not, execute S230.

[0152] S230: The first motor does not start, and the second motor does not start.

[0153] S240: The first motor starts, and the second motor does not start.

[0154] Among them, the first controller 171 controls the first motor 21 to start with a first preset step size.

[0155] S250: The operation of the first motor meets the preset conditions, such as the rotational speed being greater than the first preset rotational speed. If so, execute S260; if not, execute S240.

[0156] S260: Send a second motor start signal.

[0157] S270: The second motor meets the starting condition. If so, execute S290; if not, execute S280.

[0158] S280: The first motor starts, and the second motor does not start.

[0159] S290: The first motor starts, the second motor starts, and they operate under preset conditions, such as operating at full duty cycle respectively.

[0160] The first controller 171 sends a signal to the second controller that controls the second motor 22, so that the second controller starts the second motor 22. Among them, the second controller 172 controls the second motor 22 to start with a second preset step size. The second preset step size is greater than or equal to the first preset step size to shorten the starting experience time of the two motors. In this embodiment, when the first motor 21 starts stably, the first motor 21 operates at full duty cycle. When the second motor 22 starts stably, both the first motor 21 and the second motor 22 operate at full duty cycle. It can be understood that the change in the motor speed can be obtained through modulation and calculation of the electrical characteristic parameters of the motor, such as the phase current. Among them, the full duty cycle does not necessarily mean a duty cycle of 100%. The full duty cycle refers to the maximum duty cycle in the product performance specification, which can be 90% duty cycle, 80% duty cycle, etc.

[0161] S300: The control switch is released, execute S230, the first motor does not start, and the second motor does not start.

[0162] As an embodiment, such as Figure 28As shown, the controller 17 includes a first controller 171 and a second controller 172. The first controller 171 and the second controller 172 are disposed 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 serially. A driver is also provided, including a first drive circuit 173a and a second drive circuit 173b. Among them, 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 to say, the battery pack 31 is connected to the drive circuit, and the controller is powered through the drive circuit.

[0163] In this embodiment, the first motor 21 and the second motor 22 are respectively three-phase brushless motors, including three-phase stator windings U, V, and W that are commutated electronically. In some embodiments, the three-phase stator windings U, V, and W are connected in a star configuration, and in other embodiments, the three-phase stator windings U, V, and W are connected in a delta configuration. 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 fewer or more than three phases.

[0164] 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 switching elements Q1, Q2, Q3, Q4, Q5, and Q6. The gate terminal of each switching 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 switching element is connected to the stator windings U, V, and W of the first motor 21. The switching elements Q1-Q6 receive the control signal from the first controller 171 to change their respective conduction states, thereby changing the current applied by the battery pack 31 to 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 can be understood that the above switching elements may also be any other type of solid-state switch, such as insulated gate bipolar transistor (IGBT), bipolar junction transistor (BJT), etc.

[0165] Specifically, the controller controls the on or off state of the switching elements in the drive circuit through a control chip. In some embodiments, the controller controls the ratio between the on-time and 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.

[0166] Among them, the first controller 171 further includes a first ADC drive module, which collects electrical characteristic parameters such as phase current and bus voltage through the first ADC drive module. The second controller 172 further includes a second ADC drive module, which collects electrical characteristic parameters such as phase current and bus voltage through the first ADC drive module.

[0167] After the power circuit between the battery pack 31 and the drive circuit is turned on, the drive circuit transfers the current of the battery pack 31 to the controller. That is, the first drive circuit 173a transfers the current to the first controller 171, and the second drive circuit 173b transfers the current to the second controller 172. The first controller 171 detects the preset parameters through the first ADC drive module, sends the detected parameters to the first PWM drive control module of the first controller 171 in signal mode, and the first PWM drive control module sends the PWM control signal to the first drive circuit 173a to control the ratio between the on-time and 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, sends the detected parameters to the second PWM drive control module of the second controller 172 in signal mode, and the first PWM drive control module sends the PWM control signal to the second drive circuit 173b to control the ratio between the on-time and off-time of the drive switch based on the PWM control signal. The preset parameters include parameters such as phase current, bus voltage, bus current, freewheeling time, and demagnetization time. The preset parameters detected by the first controller 171 and the preset parameters detected by the second controller 172 may be the same or different.

[0168] As Figure 30 shown, the specific control process is as follows:

[0169] S411: The control switch 81 is activated.

[0170] During operation, the first controller 171 detects that the control switch 81 is activated, that is, it receives a start signal.

[0171] S412: The first motor meets the start condition. If so, execute S141; if not, execute S413.

[0172] S413: The first motor does not start, and the second motor does not start.

[0173] S414: The first motor starts, and the second motor does not start.

[0174] The first controller 171 controls the first motor 21 to start.

[0175] S415: The operation of the first motor meets the first preset condition, such as the rotational speed being greater than the first preset rotational speed. If so, execute S414; if not, execute S416 and S417.

[0176] Taking the rotational speed as an example, the first controller 171 first determines the relationship between the rotational speed of the first motor 21 and the first rotational speed threshold. If the rotational speed of the first motor 21 is higher than the first rotational speed threshold, the first motor 21 maintains its current operating state to drive the output shaft 30, and the second motor 22 does not need to start. Optionally, the first rotational speed threshold is 5000 RPM.

[0177] S416: The second motor starts and operates under the second preset condition.

[0178] Optionally, the second motor 22 enters the hot standby state, that is, the second motor starts and maintains the preparation state for operating under the second preset condition. Optionally, still taking the rotational speed as an example, the second preset rotational speed is less than the first rotational speed threshold, and the second preset rotational speed is the optimal output efficiency rotational speed of the second motor. Optionally, the second preset rotational speed is 4500 RPM.

[0179] S417: The operation of the first motor meets the second preset condition, such as the rotational speed being greater than the second preset rotational speed. If so, execute S415; if not, execute S418.

[0180] S418: The second motor operates under the third preset condition, and the first motor operates under the second preset condition.

[0181] When the rotational speed of the first motor 21 is less than the preset second preset rotational speed, start the second motor 22 to operate under the third preset condition. At the same time, control the first motor 21 to output at the second preset rotational speed. Optionally, the third preset condition is to control the second motor 22 to operate at the maximum duty cycle when starting is completed. The first motor operates at a constant speed at the second preset rotational 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.

[0182] S419: The operation of the first motor meets the fourth preset condition, such as the rotational speed being less than the fourth preset rotational speed. If so, execute S420; if not, execute S418.

[0183] Continuously detect the rotational speed of the first motor during operation. When the operation of the first motor 21 meets the fourth preset condition, optionally, when the rotational speed is not less than the fourth preset rotational 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 rotational speed is less than the second preset rotational speed. For example, the fourth preset rotational speed is 3500 RPM.

[0184] S420: The first motor and the second motor operate at full duty cycle respectively.

[0185] When the rotational speed is less than the fourth preset rotational 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 operate at full duty cycle respectively. Among them, 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.

[0186] To avoid frequent switching between single and dual motor modes, in practical applications, in the dual motor mode, if the rotational speed is higher than 5000 RPM and the current is less than the current threshold after a preset time, it will switch to single motor operation.

[0187] S421: The control switch is released, and S413 is executed. The first motor does not start, and the second motor does not start.

[0188] 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. Any technical solutions obtained by using equivalent replacements or equivalent transformations fall within the protection scope of the present application.

Claims

1. A circular saw, characterized in that: include, 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; including a second drive shaft that rotates about a second axis; A power transmission mechanism, transmitting power of at least one of the first motor and the second motor to the output shaft; the torque of the first drive shaft and the second drive shaft is output through the output shaft; 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; A bottom plate is movably connected to the main body housing, and the bottom plate is formed with a bottom surface that contacts the workpiece; When viewed in orthographic projection along the extension direction of the output shaft, the projection of the center of gravity of the circular saw is located between the rear edge of the base plate and the output axis.

2. The circular saw according to claim 1, characterized in that The projection of the center of gravity of the circular saw is close to the output axis and is located at the rear side of the output axis.

3. The circular saw according to claim 1, characterized in that The cutting member extends in a cutting plane; the gripping portion is basically symmetrically arranged about a first plane; along a direction perpendicular to the base plate, the projection of the center of gravity of the circular saw is located between the cutting plane and the right edge of the base plate or basically on the first plane.

4. The circular saw according to claim 3, characterized in that The distance from the projection of the center of gravity of the circular saw to the first plane is smaller than the distance from the center of gravity of the circular saw to the cutting plane.

5. The circular saw according to claim 3, characterized in that A ratio of a distance W1 between a projection of the center of gravity of the circular saw and the first plane and a distance W2 between the cutting plane and the first plane is less than or equal to 1 / 3.

6. The circular saw according to claim 1, characterized in that The first motor, the second motor, the battery pack and the gripping portion are arranged on the same side of the cutting member, and the battery pack is at least partially arranged behind the first motor and the second motor, and the battery pack is at least partially arranged in front of the gripping portion.

7. The circular saw according to claim 1, characterized in that The first shell is formed or connected with a receiving shell, and the receiving shell is used to receive the first motor and the second motor.

8. The circular saw according to claim 7, characterized in that The bottom plate is formed with a hole extending along a first direction so that the cutting piece can pass through the bottom plate. Along the first direction, the ratio of the outer edge dimension L3 of the receiving shell to the outer edge dimension La of the main shell is greater than or equal to 0.2 and less than or equal to 0.

4.

9. The circular saw according to claim 7, characterized in that Along the output axis direction, the ratio of the outer edge dimension H1 of the receiving shell to the outer edge dimension Ha of the main body shell is greater than or equal to 0.15 and less than or equal to 0.

4.

10. The circular saw according to claim 7, characterized in that The cutting element has an outer diameter greater than 6 inches.

11. A circular saw, characterized in that: include, 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; including a second drive shaft that rotates about a second axis; a power transmission mechanism for transmitting power of at least one of the first motor and the second motor to the output shaft; A power supply, comprising at least one battery pack for providing an energy source for the motor; A main body housing, at least partially accommodating the first motor, the second motor and the power transmission mechanism; A bottom plate is movably connected to the main body housing, and the bottom plate is formed with a bottom surface that contacts the workpiece; 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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