Hand-held electric circular saw

Abstract

The application discloses a handheld electric circular saw, which comprises a saw blade, an output shaft for mounting and driving the saw blade to rotate around a first axis, a motor for driving the output shaft to rotate, a housing comprising a containing part for containing the motor and a handle part for a user to hold, and a bottom plate connected to the housing, wherein the bottom plate comprises a bottom plate plane for contacting a workpiece, and the handheld electric circular saw further comprises a reinforcing piece extending in a direction parallel to the first axis, and the reinforcing piece is fixedly connected to an upper surface of the bottom plate, and the distance between the frontmost end of the reinforcing piece and the front edge of the bottom plate is greater than or equal to 0 and less than or equal to 10 mm. The above scheme can provide the handheld electric circular saw with thin thickness and high strength, and the weight of the handheld electric circular saw is more light.

Description

Technical Field

[0001] This invention relates to a power tool, and more specifically to a handheld power tool. Background Technology

[0002] In recent years, the number of users of handheld circular saws has been increasing, and the functions of handheld circular saws have also become more and more diverse. During use, the base plate of a handheld circular saw must not only contact the surface of the workpiece but also support the entire machine; therefore, the base plate needs a certain thickness to provide sufficient strength. On the other hand, handheld circular saws are inevitably subject to bumps and drops during transportation and user use, which can cause the base plate to deform. Therefore, most handheld circular saws on the market currently use metal components with a certain thickness for the base plate to provide strength, resulting in a certain weight for the entire machine, which can make it relatively strenuous for users to operate the handheld circular saw for extended periods. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a handheld electric circular saw with low base plate thickness requirements and a lightweight overall design.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A handheld circular saw includes: a saw blade; an output shaft for mounting and driving the saw blade to rotate about a first axis; a motor for driving the output shaft to rotate; a housing including a receiving portion for accommodating the motor and a handle portion for a user to grip; a base plate connected to the housing, the base plate including a base plate plane for contacting a workpiece; the handheld circular saw further includes a reinforcing member extending in a direction parallel to the first axis, the reinforcing member being fixedly connected to the upper surface of the base plate; the distance between the foremost tip of the reinforcing member and the front edge of the base plate is greater than or equal to 0 and less than or equal to 10 mm.

[0006] Furthermore, the reinforcing member is not integrally formed with the base plate.

[0007] Furthermore, the upper surface of the reinforcing member is provided with scale lines for the user to refer to when cutting.

[0008] Furthermore, the front end of the reinforcing member is provided with a notch, and the notch and the orthographic projection of the saw blade on the plane where the base plate is located are basically aligned on a straight line.

[0009] Furthermore, the orthographic projection of the reinforcing member onto the plane containing the base plate lies within the plane of the base plate.

[0010] Furthermore, the thickness of the reinforcing member

[0011] Furthermore, the reinforcing member also forms or is connected to a bracket, which is rotatably connected to the front end of the fixed cover.

[0012] Furthermore, when the handheld electric circular saw adjusts the cutting depth, the support rotates on an axis parallel to the first axis.

[0013] Furthermore, the material of the reinforcing member. Attached Figure Description

[0014] Figure 1 This is a perspective view of the handheld electric circular saw in the first embodiment;

[0015] Figure 2 yes Figure 1 A three-dimensional view of a handheld electric circular saw from another perspective;

[0016] Figure 3 yes Figure 2 A cross-sectional view of a handheld electric circular saw;

[0017] Figure 4A This is a structural diagram of the transmission device;

[0018] Figure 4B This is a structural diagram of the transmission device from another perspective;

[0019] Figure 5A It is a 3D view of a handheld electric circular saw placed on a work surface;

[0020] Figure 5B It is a 3D view of a handheld electric circular saw with the battery pack installed and placed on the work surface;

[0021] Figure 6 yes Figure 1 Another perspective of the handheld electric circular saw in the image;

[0022] Figure 7 This is a partial exploded view of a handheld electric circular saw;

[0023] Figure 8 This is a structural diagram of the dust exhaust pipe and fixed protective cover on a handheld electric circular saw.

[0024] Figure 9 yes Figure 8 A cross-sectional view of the central dust outlet pipe and the fixed protective cover from another perspective;

[0025] Figure 10 This is a structural diagram of the base plate of a handheld electric circular saw;

[0026] Figure 11 This is a perspective view of the handheld electric circular saw in the second embodiment;

[0027] Figure 12 yes Figure 11 A cross-sectional view of a handheld electric circular saw;

[0028] Figure 13 yes Figure 11 A three-dimensional view of a handheld electric circular saw from another perspective;

[0029] Figure 14 This is another cross-sectional view of a handheld electric circular saw;

[0030] Figure 15 yes Figure 11 A structural diagram of the air inlet of a handheld electric circular saw;

[0031] Figure 16 yes Figure 11 A partially exploded view of a handheld electric circular saw;

[0032] Figure 17 yes Figure 11 The diagram shows the structure of the airflow guide section of a handheld electric circular saw. Detailed Implementation

[0033] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0034] Figure 1 The handheld circular saw 100 of the first embodiment shown can be used to cut wood, fiberboard, and plastics, etc. For ease of explanation of the technical solution of the present invention, the following are also defined: Figure 1 The front, back, left, right, top, and bottom sides are shown. (Example) Figures 1 to 3 As shown, the handheld circular saw 100 includes: a housing 11, an output shaft 121, a saw blade 122, a base plate 13, a motor 14, and a power supply. The housing 11 houses the motor 14 and other components. The motor 14 provides power and drives the output shaft 121 to rotate about a first axis 101 to output power. The saw blade 122 cuts the workpiece. The base plate 13 has a flat surface 131 for contacting the workpiece, and the saw blade 122 is positioned to pass through this surface. The power supply connects to the power source required for the handheld circular saw 100 to operate. Optionally, the power supply can be AC, connected to 120V or 220V AC mains via an AC plug. Alternatively, the power supply can be DC, for example, a battery pack 151 detachably connected to the housing 11.

[0035] like Figures 1 to 2As shown, the housing 11 has a grip portion 111 for the user to hold, and the grip portion 111 is also provided with a trigger switch 111a and a safety switch 111b. The trigger switch 111a is movably connected to the grip portion 111, allowing the user's hand to trigger the trigger switch 111a to start the handheld circular saw 100 when the user's hand is on the grip portion 111. The safety switch 111b is located on or near the grip portion 111, and is used to lock the trigger switch 111a in a position where it is not triggered by the user, thereby preventing accidental activation of the circular saw 100 and protecting the user from injury. It is understood that the safety switch 111b can be located on the left, right, or both sides of the grip portion 111. The grip portion 111 has a first end 111c and a second end 111d located in its extending direction. The housing 11 also has a connecting portion 112 for connecting the battery pack 151, the connecting portion 112 being connected to the first end 111c of the grip portion 111. Specifically, the connecting portion 112 is used to connect the battery pack 151 to provide power to the handheld circular saw 100. In this embodiment, the battery pack 151 is detachably connected to the connecting portion 112. The nominal voltage of the battery pack 151 is 18V, and the nominal capacity is 3000mAh. The battery pack 151 includes multiple battery cells, and the width of the battery pack 151 is 84mm.

[0036] See Figure 2 and Figure 3As shown, the housing 11 has a first receiving portion 113 and a second receiving portion 114. The first receiving portion 113 is connected to the second end 111d of the grip portion 111, and the second receiving portion 114 is disposed below the grip portion 111 and between the connecting portion 112 and the second receiving portion 114. The first receiving portion 113 has a first receiving cavity 113a, and the circuit board assembly 18 is disposed within the first receiving cavity 113a. In this embodiment, the housing 11 of the handheld circular saw 100 is a two-part housing, with the grip portion 111 symmetrically arranged about a first plane 102, which is perpendicular to the first axis 101. In this embodiment, the first receiving portion 113 is connected to the second end 111d of the grip portion 111, and the first receiving portion 113 is also symmetrically arranged about the first plane 102. Furthermore, the circuit board assembly 18 is placed within the first receiving cavity 113a formed by the first receiving portion 113, indicating that the circuit board assembly 18 is also symmetrically arranged about the first plane 102. The circuit board assembly 18 includes a first circuit board (not shown) and a second circuit board (not shown). The control circuitry of the handheld circular saw 100 can be partially disposed on the first circuit board and partially disposed on the second circuit board. This allows both the first and second circuit boards to be relatively small in size, avoiding the problem of a large circuit board size caused by distributing all the control circuitry onto a single board. This also facilitates the placement of the first and second circuit boards in suitable locations within the housing 11. Furthermore, the first circuit board is used to control the output power of the motor 14, and the second circuit board can be used to control the battery pack 151, but is not limited to this. In this embodiment, the circuit board assembly 18 also includes a heat sink (not shown) for heat dissipation.

[0037] The second receiving portion 114 forms a second receiving cavity 114a, within which the motor 14 and the transmission device 17 are arranged. The motor 14 can be a brushless motor 14, comprising a motor shaft 141 rotatable about a second axis 103, which is parallel to the first axis 101. Preferably, the diameter of the motor 14 is between 45 mm and 65 mm, and the ratio of the rated power of the handheld electric circular saw 100 to the diameter of the motor 14 is greater than or equal to 25 W / mm and less than or equal to 35 W / mm; more specifically, this ratio is 30 W / mm.

[0038] Specifically, a motor 14 and a transmission device 17 are arranged sequentially within the second receiving cavity 114a. It can be understood that the motor 14 is located within the second receiving cavity 114a at one end near the joint 112. See also... Figure 3As shown, the motor 14 is located at the rear upper position of the fixed cover 161. Specifically, the straight line D passes through the motor shaft 141 and the output shaft 121, and the angle between the projection of the straight line D on the first plane 102 and the projection of the base plate plane 131 on the first plane 102 is greater than or equal to 10° and less than or equal to 30°.

[0039] See Figure 4A and Figure 4B As shown, the transmission device 17 includes a belt drive assembly 171 and a gear drive assembly 172. It is understood that in other embodiments, the transmission device 17 may only include the belt drive assembly 171 or only the gear drive assembly 172. Specifically, the belt drive assembly 171 includes a first pulley 171a, a second pulley 171b, a transmission belt 171c, and an intermediate shaft 171d. The first pulley 171a is fixedly connected to the motor shaft 141, and the second pulley 171b is fixedly connected to the intermediate shaft 171d. The transmission belt 171c is tensioned on the first pulley 171a and the second pulley 171b, thereby achieving power transmission. The intermediate shaft 171d extends along a third axis 104 parallel to the first axis 101. When the motor shaft 141 rotates, the transmission belt 171c drives the second pulley 171b to rotate, and the second pulley 171b drives the intermediate shaft 171d to rotate around the third axis 104. The gear transmission assembly 172 includes a first gear 172a fixedly connected to an intermediate shaft 171d and a second gear 172b connected to an output shaft 121. The first gear 172a transmits the power output from the intermediate shaft 171d to the output shaft 121, thereby driving the output shaft 121 to rotate about the first axis 101. In this embodiment, the first gear 172a and the second gear 172b mesh with each other. It can be understood that in other embodiments, a gear for the user to transmit power between the first gear 172a and the second gear 172b may also be provided.

[0040] like Figure 2 As shown, the handheld circular saw 100 also includes a locking member 123 that locks the rotation of the output shaft 121. The locking member 123 can lock the rotation of the output shaft 121 by cooperating with any rotating part in the transmission device 17 to lock the rotation of that part. Alternatively, the locking member 123 can also directly cooperate with the motor shaft 141 or the output shaft 121 to lock the rotation of the output shaft 121. In this embodiment, see... Figure 4BAs shown, a locking groove 171e is formed on the second pulley 171b, and the locking groove 171e is recessed inward along a radial direction perpendicular to the third axis 104. A locking member 123 is partially disposed within the second receiving cavity 114a formed by the second receiving portion 114. The locking member 123 has a locking protrusion 123a that can be inserted into the locking groove 171e, and the locking member 123 can rotate relative to the housing 11. When the user operates the locking member 123 to rotate relative to the housing 11, the locking protrusion 123a is inserted into the locking groove 171e, thereby locking the rotation of the second pulley 171b, and consequently locking the rotation of the output shaft 121.

[0041] In this embodiment, the housing 11 of the handheld circular saw 100 is a two-part housing. The grip 111 is also symmetrically arranged about the first plane 102, which is perpendicular to the first axis 101. The handheld circular saw 100 in this embodiment preferably uses a motor 14 with a length of 56mm, while the motor length of a conventional circular saw is approximately 96mm. Therefore, the size of the motor 14 in this embodiment is significantly reduced, resulting in a significant reduction in the overall dimensions of the handheld circular saw 100, especially in the direction perpendicular to the plane containing the saw blade 122. See [reference needed]. Figure 6 As shown, in this direction, the size of the housing 11 of the handheld circular saw 100 is smaller than the size of the base plate 13. It can be understood that, in the direction perpendicular to the base plate 13, the projection of the housing 11 falls within the area defined by the boundary of the base plate 13. The weight of the motor 14 is a significant component of the overall weight of the handheld circular saw 100 in this embodiment. Due to the reduced size of the motor 14, it is further symmetrically arranged about the first plane 102, thus bringing the motor 14 and its center of gravity closer to the grip 111. With the battery pack 151 not installed, the distance from the center of gravity of the handheld circular saw 100 to the first plane 102 symmetrically positioned around the grip 111 does not exceed 5 mm. Preferably, after the battery pack 151 is installed on the handheld circular saw 100, it can be understood that the center of gravity of the battery pack 151 is also substantially located on the first plane 102. Therefore, regardless of whether the battery pack 151 is installed, the distance from the center of gravity of the handheld circular saw 100 to the centrally symmetrical first plane 102 of the grip 111 remains unchanged, i.e., it does not exceed 5 mm. Preferably, the center of gravity of the entire handheld circular saw 100 is located on the centrally symmetrical first plane 102 of the grip 111.

[0042] The handheld circular saw 100 also includes a guard assembly 16. The guard assembly 16 includes a fixed guard 161 and a movable guard 162. The fixed guard 161 is fixedly disposed relative to the housing 11 on the upper side of the saw blade 122, covering the upper half of the saw blade 122 along its circumference. Specifically, refer to... Figure 3As shown, the fixed cover 161 covers the upper half of the saw blade 122 radially. It is understood that the housing 11 can be indirectly connected to the base plate 13 via the fixed cover 161. Alternatively, the housing 11 can be indirectly connected to the fixed cover 161 via the base plate 13; those skilled in the art can design this according to actual needs. Furthermore, the fixed cover 161 can be made of metal, plastic, a combination of metal and plastic, or other materials. The movable cover 162 can rotate relative to the housing 11 about a first axis 101. The movable cover 162 extends at least partially to the underside of the base plate plane 131. When the movable cover 162 rotates relative to the housing 11, displacement occurs between the movable cover 162 and the fixed cover 161, exposing the saw blade 122. As the movable cover 162 rotates, the exposed portion of the saw blade 122 gradually increases. Once the movable guard 162 is moved above the base plate 13, the handheld circular saw 100 can be used for cutting.

[0043] like Figure 5A and 5B As shown, the handheld circular saw 100 can be supported on the working surface A by the movable guard 162 and the base plate 13. When the handheld circular saw 100 is supported on the working surface A by the movable guard 162 and the base plate 13, the plane 131 of the base plate is inclined relative to the working surface, and the plane where the saw blade 122 is located is basically perpendicular to the working surface A. Specifically, when the handheld circular saw 100 is placed on the working surface A without the battery pack 151 installed, it is supported on the working surface A by the movable guard 162 and the rear edge 132 of the base plate, and the plane where the saw blade 122 is located is basically perpendicular to the working surface A. When the handheld circular saw 100 is placed on the working surface A with the battery pack 151 installed, it is supported on the working surface A by the movable guard 162 and the battery pack 151, and the plane where the saw blade 122 is located is basically perpendicular to the working surface A. It should be noted that the plane where the saw blade 122 is located is basically perpendicular to the working surface A. This can be understood as the angle between the plane where the saw blade 122 is located and the working surface A not being limited to 90°, but allowing for a deviation greater than or equal to 0° and less than or equal to 10°. In some embodiments, when the handheld circular saw 100 is supported on the working surface A by the movable guard 162 and the battery pack 151 with the battery pack 151 installed, the handheld circular saw 100 can achieve better balance when placed. In other embodiments, when the handheld circular saw 100 is supported on the working surface A by the movable guard 162, the rear edge 132 of the base plate, and the battery pack 151 with the battery pack 151 installed. The support method of the handheld circular saw 100 in this embodiment differs from the traditional placement method of circular saws. The movable guard 162 and the base plate 13 are not subjected to lateral forces, extending the life of the movable guard 162 and the base plate, and making the handheld circular saw 100 safer when placed on the working surface A.

[0044] In other embodiments, when the handheld circular saw 100 is not equipped with the battery pack 151, it can be supported on the working surface A solely by the movable guard 162 and the base plate 13. Furthermore, when the handheld circular saw 100 is not equipped with the battery pack 151, it can be supported on the working surface A solely by the movable guard 162 and the rear edge 132 of the base plate. Furthermore, when the handheld circular saw 100 is not equipped with the battery pack 151, it can be supported on the working surface A solely by at least two points on the movable guard 162 and the rear edge 132 of the base plate.

[0045] The handheld circular saw 100 generates a large amount of dust when cutting workpieces. This dust is expelled from near the fixed guard 161 by the airflow generated when the motor 14 rotates. When the motor 14 reaches a certain speed, the generation and discharge of dust increase significantly, resulting in dust splashing and severely affecting the user's vision and the environment during cutting. (See also...) Figure 7 and Figure 8 As shown, in this embodiment, the fixed cover 161 is fixedly connected to the housing 11, and a dust outlet 161a and a dust outlet channel 161b are formed on the fixed cover 161. The dust outlet 161a communicates with the dust outlet channel 161b. A dust outlet pipe 163 is connected to the dust outlet channel 161b for quickly and efficiently discharging dust and debris when the handheld electric circular saw 100 is operating at high speed. Specifically, the dust outlet 161a is located on the front side of the fixed cover 161. See also... Figure 8 As shown, the saw teeth of the saw blade 122 intersect the base plate plane 131 at point B. A tangent C to a circle with a diameter equal to the diameter of the saw blade 122 passes through point B. This tangent C rotates 30° clockwise around the intersection point B within the plane of the saw blade 122 to generate a first straight line C1. The tangent C also rotates 30° counterclockwise around the intersection point B within the plane of the saw blade 122 to generate a second straight line C2. It is understood that since the fixed cover 161 covers the circumference of the saw blade 122, the first straight line C1 and the second straight line C2 will inevitably intersect with the fixed cover 161. In this embodiment, the dust outlet 161a is preferably located between the first straight line C1 and the second straight line C2. The saw teeth of the saw blade 122 intersecting the base plate plane 131 at point B can be further understood as the saw blade 122 intersecting the workpiece surface at point B when it has its maximum cutting depth. It should be noted that when the movable guard 162 is completely above the bottom plate plane 131, the movable guard 162 and the dust outlet 161a have no overlapping area in the radial direction of the saw blade 122. When the movable guard 162 rotates relative to the housing 11 about the first axis 101, it does not affect the dust discharge effect of the dust outlet 161a.

[0046] The dust outlet pipe 163 is connected to the dust outlet channel 161b on the fixed cover 161 via a connector 164. Specifically, the connector 164 is fixedly installed on the dust outlet channel 161b. See also Figure 9 As shown, the dust outlet pipe 163 is a pipe open at both ends, having a dust outlet pipe inlet 163a and a dust outlet pipe outlet 163b at both ends. The dust outlet pipe inlet 163a is connected to the connector 164 to connect the dust outlet pipe 163 to the dust outlet 161a. To improve dust removal efficiency, the diameter of the dust outlet pipe outlet 163b is larger than the diameter of the dust outlet pipe inlet 163a. ​​Specifically, the diameter of the dust outlet pipe outlet 163b is greater than or equal to 24 mm and less than or equal to 40 mm, and the diameter of the dust outlet pipe inlet 163a is greater than or equal to 19.5 mm and less than or equal to 32.5 mm. To prevent excessive dust from flying when the user cuts workpieces using the handheld circular saw 100, after the dust outlet pipe 163 is installed to the dust outlet 161b, the dust outlet pipe outlet 163b faces the base plate plane 131. It is understood that when the handheld circular saw 100 is working, dust enters the dust discharge channel 161b through the dust outlet 161a located on the fixed cover 161, then enters the dust discharge pipe 163, and finally is discharged downwards through the dust discharge pipe outlet 163b, further reducing the obstruction of the user's view during dust discharge. Preferably, see Figure 9 The sectional view of the dust outlet pipe 163 shown shows that the angle between lines 107 and 108 in the plane of the sectional view is α. It can be understood that the angle formed by the dust outlet pipe outlet 163b and the bottom plate plane 131 is α. Specifically, the value of angle α is greater than or equal to 0 and less than 90°.

[0047] In this embodiment, the dust exhaust pipe 163 is located directly in front of the saw blade 122 and the grip portion 111. The dust exhaust hole 161a, the dust exhaust channel 161b, the grip portion 111, and the connecting portion 112 are substantially aligned on a straight line in the orthographic projection of a reference plane perpendicular to the cutting plane of the saw blade 122. It can be understood that the grip portion 111, the connecting portion 112, and the saw blade 122 are arranged approximately symmetrically about the first plane 102. Furthermore, the dust exhaust hole 161a, located on the front side of the fixed cover 161, is also arranged approximately symmetrically about the first plane 102.

[0048] To allow users to determine the direction of dust discharge without it hitting their bodies, the connector 164 preferably has a rotating cavity 164a, within which the dust outlet pipe 163 can rotate after being installed on the connector 164. Furthermore, with the first plane 102 as the center plane, the dust outlet pipe 163 can rotate left or right within the rotating cavity 164a on the connector 164 by an angle greater than or equal to 0° and less than or equal to 150°. It can be understood that the stop for the dust outlet pipe 163 at its maximum rotation angle within the rotating cavity 164a on the connector 164 is the housing 11. That is, when the dust outlet pipe 163 rotates left or right to its maximum angle of 150°, it contacts the housing 11, and the presence of the housing 11 prevents the dust outlet pipe 163 from rotating further. Users may rotate the dust outlet pipe 163 to a suitable position according to actual usage conditions or personal habits. Since a certain reaction force is generated when dust is discharged through the dust outlet pipe, the dust outlet pipe 163 may move in the left and right directions. In this embodiment, in order to prevent the rotatable dust outlet pipe 163 from being unable to be fixed in the position required by the user, a damping element 165 is also provided between the dust outlet pipe 163 and the connecting member 164 to increase the friction between the two.

[0049] When the handheld circular saw 100 is cutting a workpiece, the base plate 13 needs to support the housing 11. Therefore, the base plate 13 is generally made of metal to ensure that it has a certain strength. When the user is using the handheld circular saw 100, it may be accidentally dropped, causing the edges of the base plate 13 to deform, such as curling. Since the base plate 13 needs to be in contact with the workpiece surface during the cutting operation, if the edges of the base plate 13 are deformed, it will affect the contact between the base plate 13 and the workpiece surface, thus affecting the cutting effect. In this embodiment, the rear edge 132 of the base plate 13, as well as the left edge (not shown) and right edge (not shown), are all designed to be turned upwards. The base plate 13 designed in this way is less prone to edge deformation when dropped.

[0050] See Figure 9As shown, the base plate 13 also includes a reinforcing member 134 for strengthening the base plate 13. The reinforcing member 134 is fixedly connected to the upper surface of the base plate 13. The reinforcing member 134 is disposed at the front edge 134 of the base plate 13 and extends in a direction parallel to the first axis 101. Specifically, the length of the reinforcing member 134 in the extending direction is less than or equal to the length of the front edge 135 of the base plate, that is, the reinforcing member 134 can be stacked and installed on the upper surface of the base plate 13. The distance between the foremost point of the reinforcing member 134 and the front edge 135 of the base plate is greater than or equal to 0 and less than or equal to 10 mm. Preferably, the distance between the foremost point of the reinforcing member 134 and the front edge 135 of the base plate is approximately 0. It should be noted that the reinforcing member 134 and the base plate 13 are not integrally formed. The upper surface of the reinforcing member 134 is also provided with scale lines 1342 for the user to refer to when performing cutting operations. The front end of the reinforcing member 134 is also provided with a notch 1343. Furthermore, the orthographic projections of the notch 1343 and the saw blade 122 onto the plane containing the base plate plane 131 are basically set on a straight line.

[0051] In this embodiment, the reinforcing member 134 forms or is connected to a bracket 1341. The reinforcing member 134 is fixedly connected to the base plate 13 and also rotatably connected to the fixed cover 161 via the bracket 1341. Preferably, the bracket 1341 is a hinge, allowing for a rotatable connection between the bracket 1341 and the fixed cover 161. It is understood that when the user adjusts the cutting depth of the handheld circular saw 100, the base plate 13 rotates relative to the housing 11 about the fourth axis 106. The bracket 1341 is fixedly connected to the base plate 13, and rotates relative to the fixed cover 161 about an axis parallel to the first axis 101. Since the reinforcing member 134 is located near the front edge 135 of the base plate, the front edge 35 of the base plate has good strength even without special treatment. In this embodiment, the reinforcing member 134 is fixedly connected to the base plate 13 by screws. However, it is understood that other methods can also be used to fix the reinforcing member 134 to the upper surface of the base plate 13. The upper surface of the reinforcing member 134 is also provided with an indicator scale for indicating the position of the saw blade 122 to facilitate the user's cutting operation.

[0052] See Figures 1 to 4AAs shown, the housing 11 is provided with ventilation openings for airflow. Specifically, in this embodiment, the housing 11 is provided with an air inlet 115, a first air outlet 116, and a second air outlet 117. The air inlet 115 is preferably located on the housing 11 near the output shaft 141 of the motor 14, the first air outlet 116 is preferably located on the housing 11 near the second pulley 171b of the transmission device 17, and the second air outlet 117 is preferably located on the housing 11 near the fan 142. In this embodiment, the fan 142 is preferably a centrifugal fan. When the motor 14 starts, the fan 142 begins to operate. Airflow enters the housing 11 through the air inlet 115, flows through the motor 14, then a portion of the airflow flows through the transmission device 17 and finally exits from the first air outlet 116, while the other portion, after passing through the fan 14, finally exits the housing 11 through the second air outlet 117. It should be noted that the first air outlet 116 is preferably located on the housing 11 near the second pulley 171b of the transmission device 17. The second pulley 171b drives the intermediate shaft 171d to rotate around the third axis 104. See [link to relevant documentation] Figure 4B As shown, the intermediate shaft 171d is connected to the shaft locking ring 171f. The shaft locking ring 171f has a fan-like structure and provides additional heat dissipation for the belt drive assembly 171. The overall heat dissipation effect of this embodiment is good, and it can dissipate heat from internal heat sources in a distributed manner.

[0053] Figure 11 The handheld circular saw 200 of the second embodiment shown can be used to cut wood, fiberboard, and plastics. The handheld circular saw 200 includes: a housing 21, a saw blade 222, a base plate 23, a motor 24, and a power supply. The base plate 23 has a base plate plane 231 for contacting the workpiece, and the saw blade 222 is positioned to pass through the base plate plane 231. The power supply is used to connect to the power required for the handheld circular saw 200 to operate. Specifically, the power supply can optionally be an AC power source, connected to 120V or 220V AC mains power via an AC plug. The power supply can also be in the form of DC power, for example, a battery pack 251 that can be detachably connected to the housing 21.

[0054] See Figures 11 to 14As shown, the handheld circular saw 200 also includes a guard assembly 26, which includes a fixed guard 261 and a movable guard 262. The fixed guard 261 is fixedly disposed above the saw blade 222 relative to the housing 21. Specifically, the fixed guard 261 covers the upper half of the saw blade 222 along its circumference. In this embodiment, preferably, the housing 21 is connected to the fixed guard 261, and the fixed guard 261 is connected to the base plate 23, meaning the housing 21 is indirectly connected to the base plate 23 via the fixed guard 261. Alternatively, the housing 21 can be connected to the base plate 23, and the base plate 23 can be connected to the fixed guard 261, meaning the housing 21 is indirectly connected to the fixed guard 261 via the base plate 23. The connection relationship is not limited here, and those skilled in the art can design according to actual needs. Furthermore, the fixed guard 261 can be made of metal, plastic, a combination of metal and plastic, or other materials. The movable guard 262 extends at least partially to the underside of the base plate plane 231. As the movable guard 262 rotates relative to the housing 21, displacement occurs between the movable guard 262 and the fixed guard 261, exposing the saw blade 222. As the movable guard 262 rotates, the exposed portion of the saw blade 222 gradually increases. Once the movable guard 262 is fully moved above the base plate 23, the handheld circular saw 200 can be used for cutting operations.

[0055] The housing 21 has a grip portion 211 for the user to hold, and the grip portion 211 is also provided with a trigger switch 211a and a safety switch 211b. The trigger switch 211a is movably connected to the grip portion 211, allowing the user's hand to activate the trigger switch 211a to start the handheld circular saw 200 when the user's hand is on the grip portion 211. The safety switch 211b is located on or near the grip portion 211, and is used to lock the trigger switch 211a in a position where it has not been triggered by the user, thereby preventing accidental activation of the circular saw 200 and protecting the user from injury. It is understood that the safety switch 211b can be located on the left, right, or both sides of the grip portion 211. The grip portion 211 has a first end 211c and a second end 211d located in its extending direction. Specifically, the first end 211c of the grip 211 is the rear end of the grip 211, and the second end 211d is the front end of the grip 211. The housing 21 also has a connecting portion 212 for connecting the battery pack 151, which is connected to the first end 211c of the grip 211. Specifically, the connecting portion 212 is used to connect the battery pack 251 to provide power to the handheld circular saw 200. In this embodiment, the battery pack 251 is detachably connected to the connecting portion 212. The nominal voltage of the battery pack 251 is 18V, and the nominal capacity is 3000mAh. The battery pack 251 includes multiple battery cells, and the width of the battery pack 251 is 84mm. The second end 211d of the grip 211 is fixedly connected to the top of the fixed cover 261.

[0056] The housing 21 also includes a motor housing 213 for accommodating the motor 24. The motor housing 213 has a motor receiving cavity (not shown), and the motor 24 is disposed within the motor receiving cavity. The motor housing 213 is fixedly connected to the fixed cover 261 and extends in a direction perpendicular to the cutting plane of the saw blade 222. The housing 21 also includes a receiving portion 214 for accommodating the circuit board assembly 28. Specifically, the receiving portion 214 is located below the grip portion 211 and extends in a front-rear direction, connecting the connecting portion 212, the motor housing 213, and the fixed cover 261. The circuit board assembly 28 includes a first circuit board (not shown) and a second circuit board (not shown). The control circuit of the handheld circular saw 200 can be partially disposed on the first circuit board and partially disposed on the second circuit board. This allows both the first and second circuit boards to be relatively small in size, thus avoiding the problem of the circuit board being too large and inconvenient to install if all the control circuits are disposed on a single circuit board. This facilitates the placement of the first and second circuit boards in suitable positions within the housing 21. Furthermore, the first circuit board is used to control the output power of the motor 24, and the second circuit board can be used to control the battery pack 251, but is not limited thereto. In this embodiment, the circuit board assembly 28 also includes a heat sink (not shown) for heat dissipation.

[0057] See Figure 13 As shown, the housing 21 of the handheld circular saw 200 is a two-part housing. The grip 211 is symmetrically arranged about a first plane 202, which is perpendicular to the motor shaft 241. In this embodiment, the distance between the first plane 202 and the cutting plane where the saw blade 222 is located is greater than or equal to 0 mm and less than or equal to 10 mm. With this design, the centerline of the grip 211 located in the second plane 202 and the cutting line formed by the saw blade 222 are approximately on the same straight line. When the user applies a pushing force during cutting, no axial force is generated, resulting in a better feel. The above-mentioned "approximately on the same straight line" can be understood as the distance between the centerline of the grip 211 and the cutting plane formed by the saw blade 222 being greater than or equal to 0 mm and less than or equal to 10 mm. Further, the distance between the centerline of the grip 211 and the cutting plane formed by the saw blade 222 is greater than or equal to 0 mm and less than or equal to 5 mm. Furthermore, in this embodiment, the diameter of the motor 24 is preferably set between 45mm and 65mm, while the diameter of the motor used in conventional circular saws is larger. Therefore, the size of the motor 24 in the handheld circular saw 200 of this embodiment is significantly reduced, resulting in a significant reduction in the overall dimensions of the handheld circular saw 200, especially in the direction perpendicular to the plane of the saw blade 222. In this embodiment, the ratio of the rated power of the handheld circular saw 200 to the diameter of the motor 24 is greater than or equal to 25W / mm and less than or equal to 35W / mm, and more specifically, this ratio is 30W / mm.

[0058] In this embodiment, the motor 24 is an external rotor motor, comprising a stator assembly 242, a rotor assembly 243, and a motor shaft 241. The stator assembly 242 is fixedly disposed within the motor housing cavity, and the rotor assembly 243 rotates synchronously around the stator assembly 242 and with the motor shaft 241. The stator assembly 242 is disposed on one side of the cutting plane where the saw blade 222 is located. It can be understood that the stator assembly 242 is disposed on the left or right side of the cutting plane where the saw blade 222 is located. Further, the motor housing 213 for accommodating the motor 14 is disposed on the left or right side of the cutting plane where the saw blade 222 is located. In this embodiment, the stator assembly 242 is disposed on the right side of the fixed cover 261, that is, the motor 14 is located on the right side of the cutting plane where the saw blade 222 is located. Alternatively, it can be disposed on the left side of the fixed cover 261 or the cutting plane where the saw blade 222 is located. The distance between the side of the motor housing 213 away from the fixed cover 261 and the end face of the fixed cover 261 near the motor housing 213 is greater than or equal to 50mm and less than 70mm.

[0059] When the handheld circular saw 200 is cutting a workpiece, the base plate 23 needs to support the housing 21. Therefore, the base plate 23 is generally made of metal to ensure that it has a certain strength. The base plate 23 in this embodiment is designed the same as the base plate 13 in the first embodiment, including a reinforcing member 234 on the front side of the base plate 23. In addition, in this embodiment, the fixed cover 261 is also equipped with the same dust removal device as in the first embodiment, including a dust removal connecting pipe 261b, a dust removal pipe 263, etc., to discharge the dust generated when the handheld circular saw 200 is working into the air. One of the differences between the handheld circular saw 200 in this embodiment and the first embodiment is that the handheld circular saw 200 in this embodiment is supported by the movable cover 262, the base plate 23, and the motor housing 213 when placed on the work surface. The handheld circular saw 200 designed in this way is more stable when the movable cover 262 is not open, that is, when it is not working.

[0060] When the handheld circular saw 200 has its maximum cutting depth, the dimension h of the handheld circular saw 200 in the vertical direction perpendicular to the base plate plane 231 is greater than the diameter of the saw blade 222 and less than or equal to 200 mm. Further, the diameter of the saw blade 222 is greater than or equal to 110 mm and less than or equal to 150 mm. The ratio of the weight of the handheld circular saw 200 without the battery pack 251 to the diameter of the saw blade 222 is greater than or equal to 9 and less than or equal to 16. Further, the ratio of the weight of the handheld circular saw 200 without the battery pack 251 to the diameter of the saw blade 222 is greater than or equal to 11 and less than or equal to 13. Further, the weight of the handheld circular saw 200 without the battery pack 251 is greater than or equal to 1400 g and less than or equal to 1800 g.

[0061] See Figures 15 to 17 As shown, the handheld circular saw 200 also includes a fan 291 for providing cooling airflow to components such as the motor 24 and circuit board assembly 28. The fan 291 is disposed inside the motor housing 213 and located on the side of the motor 24 away from the fixed cover 261. The fan 291 is preferably a centrifugal fan and rotates synchronously with the motor shaft 241. The motor 24 also includes a motor bearing (not shown), and the orthographic projections of the motor bearing and the fan 291 on a plane perpendicular to the cutting plane overlap. The motor housing 213 is provided with a housing outlet 217 corresponding to the position of the fan 291. Specifically, the housing outlet 217 is located in the radial direction of the fan 291. The housing 21 also forms an air inlet 216 for airflow within the housing 21, and the air inlet 216 is preferably located between the joint 212 and the first receiving portion 214 for placing the circuit board assembly 28. When the motor 24 starts, the fan 291 starts working. Airflow enters the housing 21 from the air inlet 216, flows through the circuit board assembly 28 set in the first receiving part 214, then passes through the motor 24, and flows out of the housing 21 from the housing outlet 217, thereby carrying away the heat generated by the circuit board assembly 28 and the motor 24 when the handheld electric circular saw 200 is working, achieving efficient heat dissipation.

[0062] In this embodiment, see Figure 16As shown, the housing 21 also includes an airflow guide portion 292 disposed on the outside of the motor housing 213, and the airflow guide portion 292 is fixedly connected to the motor housing 213 and the fixed cover 261. Specifically, the airflow guide portion 292 forms an airflow guide channel 292a communicating with the housing air outlet 217, for guiding the airflow flowing through the housing air outlet 217 to the front end of the base plate 23. The airflow guide portion 292 forms an air outlet 292b communicating with the airflow guide channel 292a. Specifically, the air outlet 292b is located on the front side of the fixed cover 261 and above the base plate 23. When motor 24 starts, fan 291 begins to operate. Airflow enters housing 21 through inlet 216, flows through circuit board assembly 28 located in first receiving part 214, then through motor 24, flows out from housing outlet 217 to airflow guide channel 292a, and finally flows out from outlet 292b, thereby carrying away the heat generated by circuit board assembly 28 and motor 24 during operation of handheld circular saw 200, achieving efficient heat dissipation. Simultaneously, a portion of the airflow from outlet 292b blows towards the front of base plate 23, meaning the airflow reaches the surface of reinforcing member 234, thus carrying away dust and debris from the front surface of base plate 23 during operation, ensuring the user can observe the markings on the upper surface of reinforcing member 234 during cutting, improving cutting efficiency. In this embodiment, the airflow guide 292 extends along the outer surface of the motor housing 213 and the fixed cover 262, forming an airflow guide channel 292a for airflow circulation and guidance. It is fixedly connected to the motor housing 213 and the fixed cover 262 by screws, allowing the gas flowing from the housing outlet 217 to be blown out from the outlet 292b to the front end of the base plate 23 through the airflow guide channel 292a to the maximum extent possible, thus improving dust blowing efficiency while achieving high heat dissipation. In this embodiment, the airflow guide 292 is made of plastic; however, it can be made of other materials, such as metal or silicone. It is understood that after the airflow guide 292 is installed on the housing 23, it forms an airflow guide channel 292a with the outer surface of the motor housing 213 and the fixed cover 261 for airflow circulation and guidance. Alternatively, the airflow guide 292 itself can form an independent airflow guide channel 292a; this is not a limitation.

[0063] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A handheld circular saw, comprising: The saw blade acts on the workpiece; An output shaft is used to mount the saw blade and drive the saw blade to rotate about a first axis. An electric motor is used to drive the output shaft to rotate; The housing includes a motor housing for accommodating the motor and a single grip for a user to hold; The base plate includes at least a base plate plane for contacting the workpiece; in, The handheld electric circular saw also includes a reinforcing member extending in a direction parallel to the first axis, the reinforcing member being fixedly connected to the upper surface of the base plate; The distance between the foremost tip of the reinforcing member and the front edge of the base plate is greater than or equal to 0 and less than or equal to 10 mm; the ratio of the thickness of the reinforcing member to the thickness of the base plate is greater than or equal to 1 and less than or equal to 3. The handheld circular saw also includes a guard assembly, which includes at least a fixed guard. The fixed guard is fixedly disposed on the upper side of the saw blade relative to the housing, covering the upper half of the saw blade along the circumferential direction of the saw blade. The reinforcing member also forms or is connected to a bracket, which is rotatably connected to the front end of the fixed guard. The bracket is fixedly connected to the base plate based on the reinforcing member. When the base plate rotates relative to the housing, the bracket rotates relative to the fixed guard.

2. The handheld electric circular saw according to claim 1, characterized in that, The reinforcing member is not integrally formed with the base plate.

3. The handheld electric circular saw according to claim 2, characterized in that, The upper surface of the reinforcing member is provided with scale lines for the user to refer to when cutting.

4. The handheld electric circular saw according to claim 3, characterized in that, The front end of the reinforcing member is also provided with a notch, and the notch and the orthographic projection of the saw blade on the plane where the base plate is located are basically aligned on a straight line.

5. The handheld electric circular saw according to claim 4, characterized in that, The orthographic projection of the reinforcing member onto the plane of the base plate lies within the plane of the base plate.

6. The handheld electric circular saw according to claim 1, characterized in that, The base plate is configured to be connected to the fixed cover or the housing.

7. The handheld electric circular saw according to claim 1, characterized in that, When the handheld electric circular saw is adjusting the cutting depth, the support rotates around an axis parallel to the first axis.

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