Hand-held electric circular saw

Abstract

The application discloses a handheld electric circular saw, which comprises a saw blade, an output shaft, a motor, a shell, a bottom plate, a fixed guard and a movable guard. The shell comprises a motor casing for accommodating the motor and a holding part for being held by a user. The bottom plate comprises a bottom plate plane for contacting a workpiece. The fixed guard is fixedly connected with the shell. The movable guard is rotatably connected with the fixed guard. The handheld electric circular saw can be supported on a work surface through the movable guard and the bottom plate. When the handheld electric circular saw is supported on the work surface through the movable guard and the bottom plate, the bottom plate plane is inclined relative to the work surface, and the cutting plane where the saw blade is located is substantially perpendicular to the work surface. The above scheme can provide the handheld electric circular saw with good overall balance, which is not easy to be inclined and is more convenient for a user to hold. The guard and the bottom plate of the handheld electric circular saw are not subjected to lateral force, so that the service life of the guard and the bottom plate can be effectively prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to a power tool, in particular to a hand-held electric circular saw. BACKGROUND

[0002] In recent years, the use of hand-held electric circular saws is increasing, and the functions of the hand-held electric circular saws are also increasing. At present, most of the hand-held electric circular saws adopt three-point inclined support, which are supported on the work surface through the motor housing, the bottom plate and the movable guard. At this time, the cutting plane where the saw blade is located is not perpendicular to the work surface, and the movable guard will bear a certain lateral component force, so that the movable guard is easy to deform, resulting in shorter service life. On the other hand, when the hand-held electric circular saw adopts three-point inclined support, the center of gravity of the whole machine must be deviated to one side, which makes the user unable to experience better hand feeling during use. SUMMARY

[0003] In order to solve the problems of the prior art, the present application provides a hand-held electric circular saw which is more stable and has better hand feeling.

[0004] In order to achieve the above-mentioned object, the present application adopts the following technical scheme:

[0005] A hand-held electric circular saw, comprising: a saw blade; an output shaft for mounting the saw blade and driving the saw blade to rotate; a motor for driving the output shaft to rotate; a housing comprising a motor housing for accommodating the motor and a holding portion for a user to hold; a bottom plate connected to the housing, the bottom plate comprising a bottom plate plane for contacting a workpiece; a fixed guard fixedly connected to the housing; a movable guard rotatably connected to the fixed guard; the hand-held electric circular saw can be supported on a work surface by the movable guard and the bottom plate; when the hand-held electric circular saw is supported on the work surface by the movable guard and the bottom plate, the bottom plate plane is inclined relative to the work surface, and the cutting plane where the saw blade is located is substantially perpendicular to the work surface.

[0006] Further, the motor is located behind the fixed guard in the extension direction of the housing, and the projection of the motor on the cutting plane does not coincide with the projection of the fixed guard on the cutting plane.

[0007] Further, the motor at least comprises a motor shaft, and the included angle between the straight line formed by the projection of the motor shaft and the output shaft on the cutting plane and the projection of the bottom plate plane on the cutting plane is greater than or equal to 10° and less than or equal to 30°.

[0008] Further, the housing forms a holding portion for a user to hold, and the holding portion is symmetrically arranged about a first plane.

[0009] Further, the distance from the center of gravity of the handheld electric circular saw to the first plane is greater than or equal to 0 and less than or equal to 5mm.

[0010] Further, the handheld electric circular saw has a normal projection on a plane where the bottom plate plane is located, and the normal projection is located in the bottom plate plane.

[0011] Further, the housing is further formed with a combination part for connecting a battery pack, and the battery pack is detachably connected to the combination part.

[0012] Further, the projection of the holding part, the saw blade and the combination part on the plane where the bottom plate plane is located is approximately located on the same straight line.

[0013] Further, the housing is further formed with an air inlet and an air outlet for air flow circulation.

[0014] Further, the air outlet at least includes a first air outlet and a second air outlet, and the first air outlet and the second air outlet are located on both sides of a cutting plane where the saw blade is located. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a perspective view of the handheld electric circular saw in the first embodiment;

[0016] Figure 2 is a perspective view of the handheld electric circular saw in Figure 1 is another perspective view of the handheld electric circular saw in

[0017] Figure 3 is a sectional view of the handheld electric circular saw in Figure 2

[0018] Figure 4A is a structural view of the transmission device;

[0019] Figure 4B is another perspective view of the transmission device;

[0020] Figure 5A is a perspective view of the handheld electric circular saw placed on a work surface;

[0021] Figure 5B is a perspective view of the handheld electric circular saw after the battery pack is installed and placed on a work surface;

[0022] Figure 6 is another perspective view of the handheld electric circular saw in Figure 1

[0023] Figure 7 is a partial exploded view of the handheld electric circular saw;

[0024] Figure 8 ​​This is a structural diagram of the dust exhaust pipe and fixed protective cover on a handheld electric circular saw.

[0025] Figure 9 yes Figure 8 A cross-sectional view of the central dust outlet pipe and the fixed protective cover from another perspective;

[0026] Figure 10 This is a structural diagram of the base plate of a handheld electric circular saw;

[0027] Figure 11 This is a perspective view of the handheld electric circular saw in the second embodiment;

[0028] Figure 12 yes Figure 11 A cross-sectional view of a handheld electric circular saw;

[0029] Figure 13 yes Figure 11 A three-dimensional view of a handheld electric circular saw from another perspective;

[0030] Figure 14 This is another cross-sectional view of a handheld electric circular saw;

[0031] Figure 15 yes Figure 11 A structural diagram of the air inlet of a handheld electric circular saw;

[0032] Figure 16 yes Figure 11 A partially exploded view of a handheld electric circular saw;

[0033] Figure 17 yes Figure 11 The diagram shows the structure of the airflow guide section of a handheld electric circular saw. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0035] 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 3As shown, the handheld electric circular saw 100 comprises a housing 11, an output shaft 121, a saw blade 122, a base plate 13, a motor 14, and a power supply device. The housing 11 is configured to accommodate the motor 14 and other components. The motor 14 is configured to provide a power source and drive the output shaft 121 to rotate about the first axis 101 to output power. The saw blade 122 is configured to cut workpieces. The base plate 13 is formed with a base plate plane 131 configured to contact workpieces, and the saw blade 122 is arranged to pass through the base plate plane 131. The power supply device is configured to access a power source required for the handheld electric circular saw 100 to work. The power supply device can be optionally configured as an alternating current power supply, which is accessed through an alternating current plug to access 120V or 220V alternating current mains. The power supply device can also be in the form of direct current, for example, a battery pack 151 that can be detachably coupled to the housing 11.

[0036] As shown in Figures 1 to 2 , the housing 11 is formed with a holding portion 111 configured to be held by a user. The holding portion 111 is further provided with a trigger switch 111a and a safety switch 111b. The trigger switch 111a is movably connected to the holding portion 111. When the user's hand is held on the holding portion 111, the user's hand can trigger the trigger switch 111a to start the handheld electric circular saw 100. The safety switch 111b is arranged on or near the holding portion 111. The safety switch 111b is configured to lock the trigger switch 111a in a position not triggered by the user, thereby preventing accidental start of the electric circular saw 100 and protecting the user from injury. It can be understood that the safety switch 111b can be arranged on the left side or the right side of the holding portion 111 or on both sides. The holding portion 111 has a first end 111c and a second end 111d extending in a first direction. The housing 11 is further formed with a coupling portion 112 configured to couple the battery pack 151. The coupling portion 112 is connected to the first end 111c of the holding portion 111. Specifically, the coupling portion 112 is configured to couple the battery pack 151 to provide power for the handheld electric circular saw 100. In this embodiment, the battery pack 151 is detachably coupled to the coupling portion 112. The battery pack 151 has a nominal voltage of 18V and a nominal capacity of 3000mAh. The battery pack 151 includes a plurality of battery cells, and the width of the battery pack 151 is 84mm.

[0037] Referring to Figure 2 and Figure 3As shown, the housing 11 is formed with a first accommodating portion 113 and a second accommodating portion 114. The first accommodating portion 113 is connected to the second end 111d of the holding portion 111, and the second accommodating portion 114 is arranged below the holding portion 111 and between the joint portion 112 and the second accommodating portion 114. The first accommodating portion 113 is formed with a first accommodating cavity 113a, and the circuit board assembly 18 is arranged in the first accommodating cavity 113a. The housing 11 of the hand-held electric circular saw 100 in the embodiment is a two-piece housing, and the holding portion 111 is symmetrically arranged about the first plane 102, which is perpendicular to the first axis 101. In the embodiment, the first accommodating portion 113 is connected to the second end 111d of the holding portion 111, and the first accommodating portion 113 is also symmetrically arranged about the first plane 102. Further, the circuit board assembly 18 is arranged in the first accommodating cavity 113a formed by the first accommodating portion 113, and it can be understood 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), and the control circuit of the hand-held electric circular saw 100 can be partially arranged on the first circuit board and partially arranged on the second circuit board. In this way, the sizes of the first circuit board and the second circuit board are both relatively small, thereby avoiding the problem that the circuit board is not convenient to arrange due to the large size of the circuit board caused by arranging all the control circuit on one circuit board, and further facilitating the arrangement of the first circuit board and the second circuit board at appropriate positions in the housing 11. Further, 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 thereto. In the embodiment, the circuit board assembly 18 further includes a heat dissipation member (not shown) for heat dissipation.

[0038] The second accommodating portion 114 is formed with a second accommodating cavity 114a, and the motor 14 and the transmission device 17 are arranged in the second accommodating cavity 114a. The motor 14 can be a brushless motor 14, and the motor 14 includes a motor shaft 141 rotatable about the 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 hand-held 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, and further, the ratio is 30 W / mm.

[0039] Specifically, the motor 14 and the transmission device 17 are arranged in the second accommodating cavity 114a in sequence. It can be understood that the motor 14 is arranged at one end of the second accommodating cavity 114a close to the joint portion 112. Referring to Figure 3As shown, the motor 14 is located at a rear upper position of the fixed shroud 161. Specifically, a 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 bottom plate plane 131 on the first plane 102 is greater than or equal to 10° and less than or equal to 30°.

[0040] Referring to Figure 4A and Figure 4B As shown, the transmission 17 includes a belt transmission assembly 171 and a gear transmission assembly 172, and it is understood that in other embodiments, the transmission 17 can include only the belt transmission assembly 171 or only the gear transmission assembly 172. Specifically, the belt transmission assembly 171 specifically includes a first belt pulley 171a, a second belt pulley 171b, a transmission belt 171c, and an intermediate shaft 171d. The first belt pulley 171a is fixedly connected with the motor shaft 141, the second belt pulley 171b is fixedly connected with the intermediate shaft 171d, and the transmission belt 171c is tensioned on the first belt pulley 171a and the second belt pulley 171b, thereby achieving power transmission. The intermediate shaft 171d extends along a third axis 104 parallel to the first axis 101, and when the motor shaft 141 rotates, the transmission belt 171c drives the second belt pulley 171b to rotate, and the second belt pulley 171b drives the intermediate shaft 171d to rotate together with the third axis 104 as the axis. The gear transmission assembly 172 includes a first gear 172a fixedly connected with the intermediate shaft 171d and a second gear 172b connected with the output shaft 121, and the first gear 172a can transmit the power output by the intermediate shaft 171d to the output shaft 121, thereby driving the output shaft 121 to rotate with the first axis 101 as the axis. In this embodiment, the first gear 172a and the second gear 172b are meshed with each other, and it is understood that in other embodiments, a gear can be provided between the first gear 172a and the second gear 172b to achieve power transmission therebetween.

[0041] As Figure 2 shown, the handheld electric circular saw 100 further includes a locking member 123 that locks the rotation of the output shaft 121, and the locking member 123 cooperates with any one of the rotating parts in the transmission 17 to lock the rotation of the part, or the locking member 123 directly cooperates with the motor shaft 141 or the output shaft 121 to lock the rotation of the output shaft 121. In this embodiment, referring to Figure 4BAs shown, the second pulley 171b is formed with a locking groove 171e which is recessed inwardly along a radial direction perpendicular to the third axis 104. The locking member 123 is partially arranged in a second accommodating cavity 114a formed by the second accommodating portion 114, and the locking member 123 is formed with a locking protrusion 123a which can be embedded in the locking groove 171e, and the locking member 123 can rotate relative to the housing 11. When the user rotates the locking member 123 relative to the housing 11, the locking protrusion 123a is embedded in the locking groove 171e so as to lock the rotation of the second pulley 171b, and further the rotation of the output shaft 121 is locked.

[0042] The housing 11 of the hand-held electric circular saw 100 in the embodiment is a two- half housing. The gripping portion 111 is also symmetrically arranged about a first plane 102 which is perpendicular to the first axis 101. The length of the motor 14 preferably adopted in the hand-held electric circular saw 100 in the embodiment is 56 mm, while the length of the motor adopted in a conventional electric circular saw is about 96 mm. Therefore, the size of the motor 14 in the hand-held electric circular saw 100 in the embodiment is significantly reduced, so that the overall size of the hand-held electric circular saw 100, especially in the direction perpendicular to the plane in which the saw blade 122 is located, is significantly reduced. See Figure 6 As shown, in this direction, the size of the housing 11 of the hand-held electric circular saw 100 is smaller than the size of the bottom plate 13. It can be understood that, in the direction perpendicular to the bottom plate 13, the projection of the housing 11 falls within the area defined by the boundary of the bottom plate 13. The weight of the motor 14 is one of the important components of the overall weight of the hand-held electric circular saw 100 in the embodiment. Since the size of the motor 14 is reduced, further, the motor 14 is symmetrically arranged about the first plane 102, so that the motor 14 and the position of its center of gravity are closer to the gripping portion 111. In the state that the battery pack 151 is not installed, the distance from the center of gravity of the hand-held electric circular saw 100 to the center-symmetrical first plane 102 of the gripping portion 111 is not more than 5 mm. Preferably, after the battery pack 151 is installed to the hand-held electric 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, whether the battery pack 151 is installed or not, the distance from the center of gravity of the hand-held electric circular saw 100 to the center-symmetrical first plane 102 of the gripping portion 111 is unchanged, i.e. not more than 5 mm. Preferably, the center of gravity of the entire hand-held electric circular saw 100 is located on the center-symmetrical first plane 102 of the gripping portion 111.

[0043] The hand-held electric circular saw 100 further comprises a shroud assembly 16. The shroud assembly 16 comprises a fixed shroud 161 and a movable shroud 162. The fixed shroud 161 is fixedly arranged on the upper side of the saw blade 122 relative to the housing 11, and covers the upper half of the saw blade 122 along the circumferential direction of the saw blade 122. Specifically, referring 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.

[0044] 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.

[0045] In some embodiments, the handheld electric circular saw 100 can be supported on the work surface A by the active shroud 162 and the bottom plate 13 only when the battery pack 151 is not installed. Further, the handheld electric circular saw 100 can be supported on the work surface A by the active shroud 162 and the bottom plate rear edge 132 only when the battery pack 151 is not installed. Further, the handheld electric circular saw 100 can be supported on the work surface A by at least two points on the active shroud 162 and the bottom plate rear edge 132 only when the battery pack 151 is not installed.

[0046] A large amount of dust is generated when the handheld electric circular saw 100 cuts a workpiece. The dust is discharged from the vicinity of the fixed shroud 161 under the action of the airflow generated when the motor 14 rotates. When the motor 14 reaches a certain speed, the generation and discharge speed of the dust will obviously increase, thereby causing the dust to splash, which seriously affects the user's line of sight and environment when performing cutting work. Figure 7 and Figure 8 In the present embodiment, the fixed shroud 161 is fixedly connected to the housing 11, and the fixed shroud 161 is formed with a dust outlet 161a and a dust outlet passage 161b. The dust outlet 161a is in communication with the dust outlet passage 161b. The dust outlet passage 161b is connected with a dust outlet pipe 163 for quickly and efficiently discharging dust when the handheld electric circular saw 100 is working at high speed. Specifically, the dust outlet 161a is arranged on the front side of the fixed shroud 161. Referring to Figure 8 As shown in FIG. 6, the saw blade 122 intersects the bottom plate plane 131 at point B, and there is a tangent C of a circle with the diameter of the saw blade 122 passing through point B. The tangent C rotates 30° clockwise in the plane of the saw blade 122 to generate a first straight line C1, and the tangent C rotates 30° counterclockwise in the plane of the saw blade 122 to generate a second straight line C2. It can be understood that the fixed shroud 161 covers the circumferential direction of the saw blade 122, and the first straight line C1 and the second straight line C2 will inevitably intersect the fixed shroud 161. In the present embodiment, the dust outlet 161a is preferably arranged between the first straight line C1 and the second straight line C2. The saw blade 122 intersects the bottom plate plane 131 at point B, and further can be understood that the saw blade 122 intersects the surface of the workpiece at point B when the saw blade 122 has the maximum cutting depth. It should be noted that when the active shroud 162 is completely above the bottom plate plane 131, the active shroud 162 and the dust outlet 161a do not overlap in the radial direction of the saw blade 122, and the active shroud 162 rotates relative to the housing 11 about the first axis 101, which does not affect the dust discharge effect of the dust outlet 161a at all times.

[0047] The dust outlet pipe 163 is in communication with the dust outlet passage 161b on the fixed shroud 161 through a connecting piece 164. Specifically, the connecting piece 164 is fixedly installed on the dust outlet passage 161b. Referring toFigure 9 As shown, the dust outlet pipe 163 is a pipe with two open ends, and has a dust outlet pipe inlet 163a and a dust outlet pipe outlet 163b arranged at the two ends of the dust outlet pipe 163. The dust outlet pipe inlet 163a is connected with the connecting piece 164 to make the dust outlet pipe 163 communicate with the dust outlet 161a. In order to improve the dust removal efficiency, the diameter of the dust outlet pipe outlet 163b is greater than that 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. In order to avoid the dust flying seriously when the user uses the hand-held electric circular saw 100 to cut the workpiece, the dust outlet pipe outlet 163b faces the bottom plate plane 131 after the dust outlet pipe 163 is installed to the dust outlet passage 161b. It can be understood that when the hand-held electric circular saw 100 works, the dust enters the dust outlet pipe 163 through the dust outlet 161a on the fixed guard 161 after entering the dust outlet passage 161b, and finally the dust is discharged downward through the dust outlet pipe outlet 163b, which further reduces the obstruction to the user's line of sight when the dust is discharged. Preferably, referring to Figure 9 As shown in the cross-sectional view of the dust outlet pipe 163, the angle between the straight line 107 and the straight line 108 in the plane of the cross-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 angle α is greater than or equal to 0 and less than 90°.

[0048] In this embodiment, the dust outlet pipe 163 is located in front of the saw blade 122 and the holding part 111. The dust outlet hole 161a, the dust outlet passage 161b, the holding part 111 and the connecting part 112 are substantially arranged on a straight line in a reference plane perpendicular to the cutting plane where the saw blade 122 is located. It can be understood that the holding part 111, the connecting part 112 and the saw blade 122 are substantially symmetrically arranged about the first plane 102. Further, the dust outlet hole 161a arranged on the front side of the fixed guard 161 is also substantially symmetrically arranged about the first plane 102.

[0049] In order to allow the user to decide the direction of dust flying by himself and prevent dust from being sprayed on the user, the connecting piece 164 is preferably provided with a rotating cavity 164a, and the dust outlet pipe 163 can rotate in the rotating cavity 164a after being installed on the connecting piece 164. Further, taking the first plane 102 as the center plane, the dust outlet pipe 163 rotates in the rotating cavity 164a on the connecting piece 164 by an angle greater than or equal to 0° and less than or equal to 150° to the left or to the right. It can be understood that the stopper of the dust outlet pipe 163 rotating in the rotating cavity 164a on the connecting piece 164 by the maximum angle is the shell 11. That is, when the dust outlet pipe 163 rotates to the left or to the right by the maximum angle of 150°, the dust outlet pipe 163 is in contact with the shell 11, and the dust outlet pipe 163 cannot rotate by a larger angle due to the existence of the shell 11. The user will rotate the dust outlet pipe 163 to a suitable position according to the actual use condition or personal habit, and due to the reaction force generated when dust is discharged through the dust outlet pipe, the dust outlet pipe 163 can move to the left or to the right. In the embodiment, in order to prevent the rotatable dust outlet pipe 163 from being unable to be fixed at the position required by the user, a damping piece 165 is further arranged between the dust outlet pipe 163 and the connecting piece 164 to increase the friction therebetween.

[0050] When the hand-held electric circular saw 100 performs a workpiece cutting operation, the bottom plate 13 needs to support the shell 11, and therefore the bottom plate 13 is generally made of metal to ensure that the bottom plate 13 has a certain strength. When the user uses the hand-held electric circular saw 100, he may accidentally drop it on the ground, thereby causing the edge of the bottom plate 13 to be deformed, for example, to be rolled. Since the bottom plate 13 needs to be in contact with the surface of the workpiece during the cutting operation of the hand-held electric circular saw 100, if the edge of the bottom plate 13 is deformed, the contact between the bottom plate 13 and the surface of the workpiece will be affected, thereby affecting the cutting effect. In the embodiment, the bottom plate rear edge 132 and the bottom plate left edge (not shown in the figure) and the bottom plate right edge (not shown in the figure) of the bottom plate 13 are all designed to be upwardly rolled, and the bottom plate 13 designed in this way is not easy to be deformed when falling.

[0051] Referring to Figure 9As shown, the bottom plate 13 further comprises a reinforcing member 134 for reinforcing the strength of the bottom plate 13. The reinforcing member 134 is fixedly connected to the upper surface of the bottom plate 13. The reinforcing member 134 is arranged at the front edge 135 of the bottom plate 13 and extends in a direction parallel to the first axis 101. In particular, 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 bottom plate 13, i.e. the reinforcing member 134 can be stacked and mounted to the upper surface of the bottom plate 13. The distance between the front end of the reinforcing member 134 and the front edge 135 of the bottom plate 13 is greater than or equal to 0 and less than or equal to 10 mm. Preferably, the distance between the front end of the reinforcing member 134 and the front edge 135 of the bottom plate 13 is substantially 0. It should be noted that the reinforcing member 134 is not integrally formed with the bottom plate 13. The upper surface of the reinforcing member 134 is further provided with a scale line 1342 for the user to refer to when performing the cutting operation. The front end of the reinforcing member 134 is further provided with a notch 1343. Further, the notch 1343 and the saw blade 122 are substantially arranged on a straight line in the projection on the plane of the bottom plate 131.

[0052] In the present embodiment, the reinforcing member 134 is formed or connected with a bracket 1341. The reinforcing member 134 is fixedly connected to the bottom plate 13 and is further rotatably connected to the fixed shroud 161 through the bracket 1341. In particular, the bracket 1341 is preferably a hinge, and the bracket 1341 is rotatably connected to the fixed shroud 161. It can be understood that when the user adjusts the cutting depth of the hand-held circular saw 100, the bottom plate 13 rotates relative to the housing 11 about the fourth axis 106, the bracket 1341 is fixedly connected to the bottom plate 13, and the bracket 1341 rotates relative to the fixed shroud 161 about an axis parallel to the first axis 101. Since the reinforcing member 134 is arranged near the front edge 135 of the bottom plate 13, the front edge 135 of the bottom plate 13 has good strength without being conveniently processed. In the present embodiment, the reinforcing member 134 is fixedly connected to the bottom plate 13 by screw fastening, and it can be understood that other ways can be used to fix the reinforcing member 134 to the upper surface of the bottom plate 13. The upper surface of the reinforcing member 134 is further provided with an indication scale for indicating the position of the saw blade 122 to facilitate the user to perform the cutting operation.

[0053] Referring to Figures 1 to 4AAs shown, the housing 11 is provided with air vents for air flow. 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 arranged on the housing 11 near the output shaft 141 of the motor 14, the first air outlet 116 is preferably arranged on the housing 11 near the second pulley 171b of the transmission 17, and the second air outlet 117 is preferably arranged on the housing 11 near the fan 142. In this embodiment, the fan 142 is preferably a centrifugal fan. When the motor 14 is started, the fan 142 starts to work, air flows into the housing 11 from the air inlet 115, flows through the motor 14, then part of the air flow flows through the transmission 17, and finally flows out from the first air outlet 116, and the other part flows through the fan 142 and finally flows out from the second air outlet 117. It should be noted that the first air outlet 116 is preferably arranged on the housing 11 near the second pulley 171b of the transmission 17, which drives the intermediate shaft 171d to rotate about the third axis 104. Referring to Figure 4B As shown, the intermediate shaft 171d is connected to the shaft lock ring 171f. The shaft lock ring 171f is a fan-like structure, which plays an additional role in heat dissipation for the belt transmission assembly 171. The whole machine in this embodiment has good heat dissipation effect, which can perform shunt heat dissipation for internal heat sources.

[0054] Figure 11 The hand-held electric circular saw 200 of the second embodiment shown can be used to cut wood, fiberboard and plastic, etc. The hand-held electric circular saw 200 comprises a housing 21, a saw blade 222, a base plate 23, a motor 24, and a power supply device. The base plate 23 is formed with a base plate plane 231 for contacting a workpiece, and the saw blade 222 is arranged to pass through the base plate plane 231. The power supply device is used to access the power required for the hand-held electric circular saw 200 to work. Specifically, the power supply device can be optionally arranged as an alternating current power supply, which is connected to 120V or 220V alternating current mains through an alternating current plug. The power supply device can also be in the form of direct current, for example, a battery pack 251 that can be detachably connected to the housing 21.

[0055] Referring to Figures 11 to 14As shown, the handheld electric circular saw 200 further comprises a shroud assembly 26, which comprises a fixed shroud 261 and a movable shroud 262. The fixed shroud 261 is fixedly arranged on the upper side of the saw blade 222 relative to the housing 21, and specifically, the fixed shroud 261 covers the upper half of the saw blade 222 along the circumferential direction of the saw blade 222. In this embodiment, the housing 21 is preferably connected to the fixed shroud 261, and the fixed shroud 261 is connected to the bottom plate 23, i.e., the housing 21 is indirectly connected to the bottom plate 23 through the fixed shroud 261. Of course, the housing 21 can also be connected to the bottom plate 23, and the bottom plate 23 is connected to the fixed shroud 261, i.e., the housing 21 is indirectly connected to the fixed shroud 261 through the bottom plate 23. The connection relationship herein is not limited, and those skilled in the art can design according to actual needs. In addition, the material of the fixed shroud 261 can be metal or plastic, or a combination of metal and plastic, or other materials. The movable shroud 262 at least partially extends to the lower side of the bottom plate plane 231. When the movable shroud 262 rotates relative to the housing 21, the movable shroud 262 and the fixed shroud 261 will be displaced to expose the saw blade 222, and with the rotation of the movable shroud 262, the exposed part of the saw blade 222 gradually increases. When the movable shroud 262 moves to the upper side of the bottom plate 23, the handheld electric circular saw 200 can be used for cutting work.

[0056] The housing 21 is formed with a holding portion 211 for a user to hold, and the holding portion 211 is further provided with a trigger switch 211a and a safety switch 211b. The trigger switch 211a is movably connected with the holding portion 211, and when the user's hand holds the holding portion 211, the user's hand can trigger the trigger switch 211a to start the handheld electric circular saw 200. The safety switch 211b is arranged on or near the holding portion 211, and the safety switch 211b is used to lock the trigger switch 211a in a position not triggered by the user, thereby preventing accidental start of the electric circular saw 200 and protecting the user from being hurt. It can be understood that the safety switch 211b can be arranged on the left side or the right side of the holding portion 211 or on both sides. The holding portion 211 has a first end 211c and a second end 211d in the extending direction thereof, respectively. Specifically, the first end 211c of the holding portion 211 is the rear end of the holding portion 211, and the second end 211d is the front end of the holding portion 111. The housing 21 is further formed with a combination portion 212 for connecting the battery pack 151, and the combination portion 212 is connected with the first end 211c of the holding portion 211. Specifically, the combination portion 212 is used to connect the battery pack 251 to provide electric energy for the handheld electric circular saw 200. In the embodiment, the battery pack 251 is detachably connected to the combination portion 212. The nominal voltage of the battery pack 251 is 18V, and the nominal capacity is 3000mAh. The battery pack 251 includes a plurality of battery cells, and the width of the battery pack 251 is 84mm. The second end 211d of the holding portion 211 is fixedly connected above the fixed guard 261.

[0057] The shell 21 further forms a motor housing 213 for accommodating the motor 24, the motor housing 213 forms a motor accommodating cavity (not shown in the figure), and the motor 24 is arranged in the motor accommodating cavity. The motor housing 213 is fixedly connected with the fixed guard 261 and extends in a direction perpendicular to the cutting plane in which the saw blade 222 is located. The shell 21 further forms an accommodating portion 214 for accommodating the circuit board assembly 28. Specifically, the accommodating portion 214 is located below the holding portion 211 and extends in the front-rear direction to connect the joint portion 212 and the motor housing 213 and the fixed guard 261. Among them, the circuit board assembly 28 includes: a first circuit board (not shown in the figure) and a second circuit board (not shown in the figure), and the control circuit of the handheld electric circular saw 200 can be partially arranged on the first circuit board and partially arranged on the second circuit board, so that the sizes of the first circuit board and the second circuit board are relatively small, thereby avoiding the problem that the size of the circuit board is relatively large due to the arrangement of all the control circuit on one circuit board, and further facilitating the arrangement of the first circuit board and the second circuit board at appropriate positions in the shell 21. Further, 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, of course, not limited thereto. In the embodiment, the circuit board assembly 28 further includes a heat dissipation member (not shown in the figure) for heat dissipation.

[0058] Referring to Figure 13 As shown, the shell 21 of the handheld electric circular saw 200 is a two-piece shell, and the holding portion 211 is symmetrically arranged about the first plane 202, and the first plane 202 is perpendicular to the motor shaft 241. In the embodiment, the distance between the first plane 202 and the cutting plane in which the saw blade 222 is located is greater than or equal to 0 mm and less than or equal to 10 mm. According to the design, the center line of the holding portion 211 located in the second plane 202 and the cutting line formed by the saw blade 222 are substantially located on the same straight line, and the user will not generate an axial force after applying a pushing force during cutting, and the hand feeling is better. The above-mentioned substantially located on the same straight line can be understood as that the distance between the center line of the holding portion 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 10 mm. Further, the distance between the center line of the holding portion 211 and the cutting plane formed by the saw blade 222 is greater than or equal to 0 and less than or equal to 5. In addition, the diameter of the motor 24 used in the embodiment is preferably set to be between 45 mm and 65 mm, and the diameter of the motor used in the conventional electric circular saw is relatively large, so that the size of the motor 24 of the handheld electric circular saw 200 in the embodiment is obviously reduced, and the overall size of the handheld electric circular saw 200, especially in the direction perpendicular to the plane in which the saw blade 222 is located, is obviously reduced. In the embodiment, the ratio of the rated power of the handheld electric circular saw 200 to the diameter of the motor 24 is greater than or equal to 25 W / mm and less than or equal to 35 W / mm, and further, the ratio is 30 W / mm.

[0059] The motor 24 in the embodiment is an outer rotor motor, which includes a stator assembly 242, a rotor assembly 243 and a motor shaft 241. The stator assembly 242 is fixedly arranged in the motor accommodating cavity, and the rotor assembly 243 surrounds the stator assembly 242 and rotates synchronously with the motor shaft 241. The stator assembly 242 is arranged on one side of the cutting plane where the saw blade 222 is located. It can be understood that the stator assembly 242 is arranged on the left side or the right side of the cutting plane where the saw blade 222 is located. Further, the motor housing 213 for accommodating the motor 14 is arranged on the left side or the right side of the cutting plane where the saw blade 222 is located. In the embodiment, the stator assembly 242 is arranged on the right side of the fixed shroud 261, i.e., the motor 14 is located on the right side of the cutting plane where the saw blade 222 is located. Of course, it can also be alternatively arranged on the left side of the cutting plane where the fixed shroud 261 or the saw blade 222 is located. The distance between the side of the motor housing 213 away from the fixed shroud 261 and the end face of the fixed shroud 261 close to the motor housing 213 is greater than or equal to 50 mm and less than 70 mm.

[0060] When the handheld electric circular saw 200 is in operation, the bottom plate 23 needs to support the housing 21, so the bottom plate 23 is generally made of metal material to ensure that the bottom plate 23 has a certain strength. The design of the bottom plate 23 in the embodiment is consistent with that of the bottom plate 13 in the first embodiment, including arranging the reinforcing member 234 on the front side of the bottom plate 23. In addition, in the embodiment, the fixed shroud 261 is also provided with the same dust removal device as in the first embodiment, including the dust removal connecting pipe 261b, the dust removal pipe 263, etc., for discharging the dust generated during the operation of the handheld electric circular saw 200 to the air. One of the differences between the handheld electric circular saw 200 in the embodiment and that in the first embodiment is that the handheld electric circular saw 200 in the embodiment is supported by the movable shroud 262, the bottom plate 23 and the motor housing 213 when placed on the working surface. The handheld electric circular saw 200 designed in this way is placed more stably when the movable shroud 262 is not opened, i.e., when it is not in operation.

[0061] When the handheld electric circular saw 200 has the maximum cutting depth, the dimension h of the handheld electric circular saw 200 in the up-down direction perpendicular to the bottom 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 electric 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 electric 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 electric circular saw 200 without the battery pack 251 is greater than or equal to 1400 g and less than or equal to 1800 g.

[0062] Referring to Figures 15 to 17 As shown, the handheld electric circular saw 200 further comprises a fan 291 for providing air flow for heat dissipation of the motor 24, the circuit board assembly 28 and other components. The fan 291 is arranged in the motor housing 213 and located at a side of the motor 24 away from the fixed shroud 261. The fan 291 is preferably arranged as a centrifugal fan and rotates synchronously with the motor shaft 241. The motor 24 further comprises a motor bearing (not shown in the figure), and the motor bearing and the fan 291 have overlapping projections in a vertical plane perpendicular to the cutting plane. The motor housing 213 is provided with a housing air outlet 217 corresponding to the position of the fan 291. Specifically, the housing air outlet 217 is arranged in the radial direction of the fan 291. The housing 21 is further formed with an air inlet 216 for air flow circulation in the housing 21. The air inlet 216 is preferably arranged between the joint 212 and the first accommodating portion 214 for placing the circuit board assembly 28. When the motor 24 is started, the fan 291 starts to work, and air flow enters the housing 21 from the air inlet 216, flows through the circuit board assembly 28 arranged in the first accommodating portion 214, then passes through the motor 24, and flows out of the housing 21 from the housing air outlet 217, thereby taking away the heat generated by the circuit board assembly 28 and the motor 24 and other components during the operation of the handheld electric circular saw 200, and achieving efficient heat dissipation.

[0063] In this embodiment, referring to Figure 16As shown, the shell 21 further comprises an air flow guide part 292 arranged outside the motor casing 213, which is fixedly connected to the motor casing 213 and the fixed shroud 261. Specifically, the air flow guide part 292 is formed with an air flow guide channel 292a in communication with the casing air outlet 217, for guiding the air flow passing through the casing air outlet 217 to the front end of the bottom plate 23. The air flow guide part 292 is formed with an air outlet 292b in communication with the air flow guide channel 292a. Specifically, the air outlet 292b is located on the front side of the fixed shroud 261 and above the bottom plate 23. When the motor 24 is started, the fan 291 starts to work, the air flow enters the shell 21 from the air inlet 216, passes through the circuit board assembly 28 arranged in the first accommodating part 214, then passes through the motor 24, flows out from the casing air outlet 217 to the air flow guide channel 292a, and finally flows out from the air outlet 292b, thereby taking away the heat generated by the circuit board assembly 28 and the motor 24 and other components during the operation of the handheld electric circular saw 200, achieving efficient heat dissipation. At the same time of achieving heat dissipation, part of the air flow flowing out from the air outlet 292b blows to the front side of the bottom plate 23, which can be understood as that the air flow can blow to the surface of the reinforcing member 234, thereby taking away the dust on the surface of the bottom plate 23 during the operation of the handheld electric circular saw 200, ensuring that the user can observe the scale on the surface of the reinforcing member 234 during the cutting process, and improving the cutting efficiency. In the embodiment, the air flow guide part 292 extends along the outer surfaces of the motor casing 213 and the fixed shroud 262, forms the air flow guide channel 292a for air flow circulation and guidance, and is fixedly connected to the motor casing 213 and the fixed shroud 262 by screw fastening, so that the air flowing out from the casing air outlet 217 can be blown out from the air outlet 292b to the front end of the bottom plate 23 through the air flow guide channel 292a to the greatest extent, achieving higher heat dissipation effect and improving dust blowing efficiency. In the embodiment, the air flow guide part 292 is made of plastic material, but can also be made of other materials such as metal and silica gel. It can be understood that after the air flow guide part 292 in the embodiment is installed to the shell 23, the outer surfaces of the motor casing 213 and the fixed shroud 261 form the air flow guide channel 292a for air flow circulation and guidance, but the air flow guide part 292 itself can also form an independent air flow guide channel 292a, which is not limited herein.

[0064] The basic principles, main features and advantages of the present application are shown and described above. Those skilled in the art should understand that the above embodiments do not limit the present application in any form, and any technical solutions obtained by equivalent replacement or equivalent transformation fall within the protection scope of the present application.

Claims

1. A handheld electric circular saw, comprising: The saw blade extends within a cutting plane; An output shaft is used to mount the saw blade and drive the saw blade to rotate. An electric motor is used to drive the output shaft to rotate; The housing includes a motor housing for accommodating the motor and a grip for a user to hold; The base plate includes at least a base plate plane for contacting the workpiece; A protective cover assembly includes a fixed protective cover and a movable protective cover, the movable protective cover being rotatably connected to the fixed protective cover; in, The motor is located behind the fixed cover in the extending direction of the housing; When the handheld circular saw is not equipped with a battery pack, it can be supported on the working surface by the movable guard and the base plate. When the handheld circular saw is supported on the working surface by the movable guard and the base plate, the plane of the base plate is inclined relative to the working surface, and the cutting plane is basically perpendicular to the working surface.

2. The handheld electric circular saw according to claim 1, characterized in that, The projection of the motor on the cutting plane does not coincide with the projection of the fixed cover on the cutting plane.

3. The handheld electric circular saw according to claim 2, characterized in that, The motor includes at least a motor shaft, and the angle between the straight line formed by the projection of the motor shaft and the output shaft onto the cutting plane and the projection of the base plate plane onto the cutting plane is greater than or equal to 10° and less than or equal to 30°.

4. The handheld electric circular saw according to claim 1, characterized in that, The housing has a grip portion for the user to hold, and the grip portion is symmetrically arranged about a first plane.

5. The handheld electric circular saw according to claim 4, characterized in that, The distance from the center of gravity of the handheld electric circular saw to the first plane is greater than or equal to 0 and less than or equal to 5 mm.

6. The handheld electric circular saw according to claim 1, characterized in that, The orthographic projection of the handheld electric circular saw onto the plane containing the base plate is within the plane of the base plate.

7. The handheld electric circular saw according to claim 4, characterized in that, The housing also has a joint for connecting a battery pack, which is detachably connected to the joint.

8. The handheld electric circular saw according to claim 7, characterized in that, The projections of the grip, the saw blade, and the connecting part onto the plane of the base plate are approximately on the same straight line.

9. The handheld electric circular saw according to claim 1, characterized in that, The housing also has an air inlet and an air outlet for airflow.

10. The handheld electric circular saw according to claim 9, characterized in that, The air outlet includes at least a first air outlet and a second air outlet, which are located on opposite sides of the cutting plane where the saw blade is located.

11. A handheld electric circular saw, comprising: The saw blade extends within a cutting plane; An output shaft is used to mount the saw blade and drive the saw blade to rotate. An electric motor is used to drive the output shaft to rotate; The housing includes a motor housing for accommodating the motor and a grip for a user to hold; The base plate includes at least a base plate plane for contacting the workpiece; A protective cover assembly includes a fixed protective cover and a movable protective cover, the movable protective cover being rotatably connected to the fixed protective cover; in, The motor is located behind the fixed cover in the extending direction of the housing; When the handheld circular saw is not equipped with a battery pack, it can be supported on the working surface by the movable guard and the base plate. When the handheld circular saw is supported on the working surface by the movable guard and the base plate, the plane of the base plate is inclined relative to the working surface, and at least two points of the rear edge of the base plate are in contact with the working surface.

12. The handheld electric circular saw according to claim 1, characterized in that, The projection of the motor on the cutting plane does not coincide with the projection of the fixed cover on the cutting plane.

13. The handheld circular saw according to claim 12, characterized in that, The motor includes at least a motor shaft, and the angle between the straight line formed by the projection of the motor shaft and the output shaft onto the cutting plane and the projection of the base plate plane onto the cutting plane is greater than or equal to 10° and less than or equal to 30°.

14. The handheld circular saw according to claim 11, characterized in that, The housing has a grip portion for the user to hold, and the grip portion is symmetrically arranged about a first plane.

15. The handheld circular saw according to claim 14, characterized in that, The distance from the center of gravity of the handheld electric circular saw to the first plane is greater than or equal to 0 and less than or equal to 5 mm.

16. The handheld circular saw according to claim 11, characterized in that, The orthographic projection of the handheld electric circular saw onto the plane containing the base plate is within the plane of the base plate.

17. The handheld circular saw according to claim 14, characterized in that, The housing also has a joint for connecting a battery pack, which is detachably connected to the joint.

18. The handheld circular saw according to claim 17, characterized in that, The projections of the grip, the saw blade, and the connecting part onto the plane of the base plate are approximately on the same straight line.

19. The handheld electric circular saw according to claim 11, characterized in that, The housing also has an air inlet and an air outlet for airflow.

20. The handheld electric circular saw according to claim 19, characterized in that, The air outlet includes at least a first air outlet and a second air outlet, which are located on opposite sides of the cutting plane where the saw blade is located.

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