Handheld electric circular saw

Abstract

The utility model discloses a handheld electric circular saw, which comprises a shell, a circular saw blade, a circular saw blade and a circular saw blade, an output shaft; a motor; a bottom plate; fixing the shield sheet; an accommodating part; the combination part is used for combining the power supply device; the first connecting part is connected with the containing part and the combining part along a first path, and the first connecting part is further provided with a handle for a user to hold; the second connecting part is connected with the accommodating part and the combining part along a second path; wherein a first connecting part and a second connecting part are arranged on the base plate, a through hole is formed between the first connecting part and the second connecting part, fingers of a user holding the handle can pass through the through hole, and the size of the handheld electric circular saw in the height direction perpendicular to the plane of the base plate is larger than or equal to 130 mm and smaller than or equal to 200 mm. By the adoption of the scheme, the single-hand small circular saw is compact in structure and high in performance.

Description

Technical Field

[0001] The utility model relates to a power tool, in particular to a handheld circular saw. Background Art

[0002] In recent years, the number of users of handheld circular saws has been increasing, and the functions of handheld power circular saws have also been increasing. At present, most handheld circular saws mostly use high-efficiency brushless motors as the driving source. Therefore, the switching elements on the circuit board for driving the brushless motor will generate more heat. If this heat cannot be discharged in time and effectively, it will greatly affect the lifespan of electronic components and even damage the components, resulting in the inability of the handheld power tool to work properly. Content of the Utility Model

[0003] To solve the deficiencies of the prior art, the utility model provides a handheld circular saw with a simple structure and good heat dissipation effect.

[0004] To achieve the above objectives, the utility model adopts the following technical solutions:

[0005] A handheld circular saw, comprising: a housing provided with a ventilation opening for air flow; an output shaft for mounting a saw blade, at least part of the saw blade extending in a cutting plane; a motor for driving the output shaft to rotate; a base plate forming a base plate plane for contacting a workpiece, the base plate plane at least partially extending in a front-rear direction; a fixed guard surrounding at least part of the saw blade; the housing including: a receiving portion forming a first receiving cavity for receiving the motor; a combining portion for combining a power supply device; a first connecting portion connecting the receiving portion and the combining portion along a first path, the first connecting portion further providing a handle for the user to hold; a second connecting portion connecting the receiving portion and the combining portion along a second path; wherein, a through hole is formed between the first connecting portion and the second connecting portion, and the through hole is arranged for the fingers of the user to pass through when holding the handle, and the size of the handheld circular saw in the height direction perpendicular to the base plate plane is greater than or equal to 150 mm and less than or equal to 200 mm.

[0006] Further, the size of the handheld circular saw in the width direction perpendicular to the cutting plane is greater than or equal to 120 mm and less than or equal to 160 mm.

[0007] Further, it further includes a circuit board, and the circuit board is arranged in a second receiving cavity formed by the combining portion.

[0008] Further, the combining portion is provided with a first air inlet.

[0009] Further, the second connecting portion is provided with a second air inlet at one end close to the receiving portion.

[0010] Furthermore, the power supply device can be set to be detachably connected to the joint part.

[0011] Furthermore, it further includes: an air guide cover which is at least arranged on the radial outside of the fan; a gear box, and the first end surface of the gear box close to the fan is set as a flat surface.

[0012] Furthermore, the first end surface of the air guide cover is attached to the first end surface of the gear box.

[0013] Furthermore, the air guide cover is formed with an air outlet which is located on the radial outside of the fan.

[0014] Furthermore, it further includes a fixed guard which is at least arranged on the partial radial outside of the saw blade.

[0015] Furthermore, when the outer diameter of the saw blade is set to be greater than or equal to 100 mm and less than or equal to 130 mm, the length of the bottom plate in the first direction is less than 190 mm. Description of the Drawings

[0016] Figure 1 is a perspective view of a hand-held circular saw;

[0017] Figure 2 is an internal structure diagram of an embodiment of a hand-held circular saw;

[0018] Figure 3 is Figure 2 the structure diagram of the air inlet of the hand-held circular saw in

[0019] Figure 4 is the structure diagram of the power supply device and the joint part of the hand-held circular saw;

[0020] Figure 5 is a partial explosion diagram of the hand-held circular saw;

[0021] Figure 6 is the structure diagram of the circuit board and the heat dissipation box of the hand-held circular saw;

[0022] Figure 7 is the structure diagram of the air outlet of the hand-held circular saw;

[0023] Figure 8 is the structure diagram of another embodiment of the hand-held circular saw;

[0024] Figure 9 is Figure 8 the structure diagram of another perspective of the hand-held circular saw in

[0025] Figure 10 is the structure diagram of yet another embodiment of the hand-held circular saw;

[0026] Figure 11 is Figure 10 a partial sectional view of a hand-held circular saw;

[0027] Figure 12 is a structural diagram of an embodiment of a circuit board and a heat dissipation box of a hand-held circular saw;

[0028] Figure 13 is a structural diagram of an embodiment of a gear box of a hand-held circular saw;

[0029] Figure 14 is a structural diagram of another perspective of an embodiment of a gear box of a hand-held circular saw;

[0030] Figure 15 is a structural diagram of an embodiment of a flipping bracket of a hand-held circular saw;

[0031] Figure 16 is a structural diagram of an embodiment of a hand-held circular saw;

[0032] Figure 17 is a structural diagram of another perspective of a hand-held circular saw. Detailed implementation manners

[0033] Referring to Figure 1 and Figure 7 shown in the figures, the present utility model provides a hand-held circular saw 1, comprising: an output shaft 11 for mounting a saw blade 12; a motor 13 for driving the output shaft 11 to rotate, the motor 13 being provided with a motor shaft 131; a power supply device 17 for supplying power to the hand-held circular saw 1; a circuit board 19 electrically connected to at least the power supply device 17 and the motor 13 to drive the motor 13 to operate; a fan 15 supported by the motor shaft 131 for generating a cooling air flow; a bottom plate 16, the saw blade 12 being arranged to pass through the bottom plate 16, and the bottom plate plane of the bottom plate 16 being used for contacting a workpiece to be cut to assist a user in using the hand-held circular saw 1 for cutting. The hand-held circular saw 1 is further provided with a fixed guard 18 covering at least the upper half of the saw blade 12 to improve the safety during the operation of the circular saw.

[0034] The hand-held circular saw 1 further includes a housing 14, and the housing 14 at least includes a receiving portion 41, a coupling portion 42, a first connecting portion 43, and a second connecting portion 44. The receiving portion 41 is formed with a first receiving cavity (not shown in the figure), and the first receiving cavity is used to receive the motor 13. The coupling portion 42 is used to couple the power supply device 17 to provide electrical energy for the operation of the motor 13. The first connecting portion 43 connects the receiving portion 41 and the coupling portion 42 along a first path, and the first connecting portion 43 is further provided with a handle 431 for the user to hold. It should be noted here that the connection between the first connecting portion 43 and the receiving portion 41 can be a direct connection or an indirect connection. As a possible embodiment, the first connecting portion 43 is directly connected to the fixed guard 18, and the fixed guard 18 is directly connected to the receiving portion 41. The same is true in the following embodiments and will not be repeated hereinafter. The second connecting portion 44 connects the receiving portion 41 and the coupling portion 42 along a second path. A through hole 45 is formed between the first connecting portion 43 and the second connecting portion 44, which enables the user's hand to easily pass through the through hole 45 when holding the handle 431. The base plate 16 is formed with a base plate plane 16a for contacting the workpiece, and the base plate plane 16a at least partially extends in the front-rear direction. Refer to Figure 2 and Figure 16 As shown, the base plate plane 16a is defined as a reference plane, the portion of the housing 14 located on the front side of the through hole 45 is defined as a first housing portion 451, and the portion of the housing 14 located on the rear side of the through hole 45 is defined as a second housing portion 452. Preferably, the ratio of the dimension e of the through hole 45 in the front-rear direction to the sum of the dimension e of the through hole 45 and the dimension f of the first housing portion 451 in the front-rear direction is greater than 0.4 and less than or equal to 1. Further, the ratio of the dimension n of the first housing portion 451 in the front-rear direction to the dimension m of the second housing portion 452 in the front-rear direction is greater than or equal to 0.7 and less than or equal to 1.8. Refer to Figure 16 and Figure 17 As shown, in some other embodiments, the dimension c of the hand-held circular saw 1 in the height direction perpendicular to the base plate plane 16a is greater than or equal to 130 mm and less than or equal to 200 mm. The above height direction can be understood as the up-down direction. In some other embodiments, the dimension d of the hand-held circular saw 1 in the width direction perpendicular to the cutting plane where the saw blade 12 is located is greater than or equal to 120 mm and less than or equal to 160 mm. The above width direction can be understood as the left-right direction.

[0035] Specifically, the power supply device 17 can preferably be set as a battery pack, and the battery pack is detachably connected to the coupling portion 42. Refer to Figure 4As shown, the joint portion 42 is provided with an insertion track 422 in the front-back direction. The power supply device 17 slides into the insertion track 422 until it is completely connected to the joint portion 42, thereby supplying power to the handheld circular saw 1. Additionally, the insertion track 422 of the joint portion 42 can be arranged in the left-right direction, and the power supply device 17 also slides into the insertion track 422 until it is completely connected to the joint portion 42. Here, those skilled in the art can design according to the actual usage environment.

[0036] Inside the housing 14, there is also a circuit board 19 and a heat dissipation box 191 disposed opposite to the circuit board 19. A drive circuit and a control circuit are installed on the circuit board 19. The drive circuit includes a switching element for switching the power supplied to the motor 13. The control circuit is used to output a drive signal to control the above drive circuit to operate the motor 13. In the embodiment of the present utility model, the motor 13 is selected as a brushless motor, the drive circuit is selected as an inverter circuit composed of switching tubes, and the control circuit is selected as a control chip. Here, there is no limitation on the specific design circuits of the above motor selection, drive circuit, and control circuit. Those skilled in the art can independently design according to the specific environment. Specifically, referring to Figure 6 As shown, the circuit board 19 is fixedly connected in the accommodation cavity 1911 of the heat dissipation box 191. The upper surface 19a of the circuit board 19 is in contact with the lower surface 191a of the heat dissipation box 191. The components on the circuit board 19 are arranged on the lower surface 19b of the circuit board 19. The heat generated by the circuit board 19 is conducted to its heat dissipation box 191 by the principle of heat conduction and then cooled by the cooling air flow, thereby dissipating heat for the circuit board 19. To enhance the heat dissipation effect of the heat dissipation box 191, preferably, the heat dissipation box 191 is designed into a comb-like structure to achieve a better heat dissipation effect.

[0037] Referring to Figure 3 As shown, the joint portion 42 of the housing 14 forms a second accommodation cavity 42a. The circuit board 19 and the heat dissipation box 191 are arranged in the second accommodation cavity 42a. The housing 14 is also provided with an air inlet and an air outlet. Among them, at least a part of the air flow path that enters the housing 14 from the air inlet and flows out of the housing 14 from the air outlet 461 is arranged on the second path. The air flow generated when the fan 15 rotates can flow in and out from different ventilation openings. Specifically, in the embodiment of the present utility model, a centrifugal fan is adopted.

[0038] Referring to Figure 2 and Figure 3 As shown, the joint portion 42 is provided with a first air inlet 421 in the front-back direction relative to the circuit board 19 and the heat dissipation box 191. One end of the first connecting portion 43 close to the accommodating portion 41 is provided with a second air inlet 432, and the second air inlet 432 is arranged on the side away from the motor 13. The second connecting portion 44 forms a first channel 442 for air circulation, and the first channel 442 is arranged along the second path. Referring to Figure 7As shown, the housing 14 further includes a wind guide cover 46. The wind guide cover 46 is at least disposed radially outside the fan 15. An air outlet 461 is provided on a side of the wind guide cover 46 away from the second air inlet 432. The first air inlet 421, the first channel 442, and the air outlet 461 form a first air path. The second air inlet 432 and the air outlet 461 form a second air path. When the fan 15 operates, air flows into the housing 14 from the first air inlet 421, passes through the circuit board 19, the heat dissipation box 191, and the first channel 442 formed by the second connecting portion 44 in the second accommodation cavity 42a of the joint portion 42, the operating motor 13, then passes through the wind guide cover 46, and finally flows out from the air outlet 461 to form a first air path; air flows into the housing 14 from the second air inlet 432, flows through the operating motor 13, then passes through the wind guide cover 46, and finally flows out from the air outlet 461 to form a second air path.

[0039] When the handheld circular saw 1 is operating, a cooling air flow is generated by the rotation of the fan 15. The air flow passes through the first air path and the second air path simultaneously, and timely and effectively takes away the heat generated by parts such as the circuit board 19 and the motor 13 during operation, improving the heat dissipation efficiency of the circuit board 19 and the motor 13 during operation. In addition, it should be noted here that, with reference to Figure 3 As shown, accessories such as switches, capacitor circuits, and wires in this embodiment do not require additional heat dissipation measures because they generate relatively little heat during operation, and are preferably disposed in the third accommodation cavity 43a formed by the first connecting portion 43.

[0040] As another specific embodiment, with reference to Figure 8 As shown, the housing 14 at least includes a receiving portion 41, a joint portion 42, a first connecting portion 43, and a second connecting portion 44. The receiving portion 41 forms a first accommodation cavity (not shown in the figure), and the first accommodation cavity is used to accommodate the motor 13. The joint portion 42 is used to connect the power supply device 17 to provide electrical energy for the operation of the motor 13. The first connecting portion 43 is connected to the receiving portion 41 and the joint portion 42 along a first path, and the first connecting portion 43 further provides a handle 431 for the user to hold. The second connecting portion 44 is connected to the receiving portion 41 and the joint portion 42 along a second path. A through hole 45 is formed between the first connecting portion 43 and the second connecting portion 44, enabling the user's hand to easily pass through the through hole 45 when holding the handle 431. The housing 14 is also provided with an air inlet and an air outlet. Among them, at least a part of the air flow circulation path that enters the housing 14 from the air inlet and flows out of the housing 14 from the air outlet 461 is disposed on the second path.

[0041] Different from the above embodiment, different air inlets are provided on the housing 14. Specifically, with reference to Figure 8As shown, a first air inlet 421 is provided in the front-rear direction of the joint portion 42 with respect to the circuit board 19 and the heat dissipation box 191. A second air inlet 432 is provided on the side of the second connecting portion 44 that is far from the through hole 45 and close to the joint portion 42. To further improve the heat dissipation efficiency, a third air inlet 411 is newly added in this embodiment, and the third air inlet 411 is preferably provided on the accommodating portion 41 of the housing 14. Specifically, referring to Figure 9 As shown, the third air inlet 411 is provided at the junction of the first surface 41a and the second surface 41b of the accommodating portion 41. It should be noted here that the third air inlet 411 can also be integrally provided on the first surface 41a or the second surface 41b of the accommodating portion 41. When the fan 15 is working, the air flow enters the housing 14 from the first air inlet 421, passes through the circuit board 19 and the heat dissipation box 191 in the second accommodating cavity 42a of the joint portion 42, the first channel 442 formed by the second connecting portion 44, and the running motor 13, and then passes through the air guide cover 46, and finally flows out from the air outlet 461, forming a first air path. At the same time, the air flow enters the housing 14 from the second air inlet 432, flows through a part of the first channel 442 of the second connecting portion 44, passes through the running motor 13 and then passes through the air guide cover 46, and finally flows out from the air outlet 461, forming a second air path; the air flow enters the housing 14 from the third air inlet 411, and then passes through the running motor 13 and flows out from the air outlet 461, forming a third air path.

[0042] When the hand-held circular saw 1 is working, a cooling air flow is generated by the rotation of the fan 15. The air flow passes through the first air path, the second air path and the third air path at the same time, and timely and effectively takes away the heat generated by parts such as the circuit board 19 and the motor 13 during operation, improving the heat dissipation efficiency of the circuit board 19 and the motor 13 during operation. In addition, it should be noted here that accessories such as switches, capacitor circuits and wires in this embodiment generate less heat during operation, so no additional heat dissipation measures are required, and they are preferably provided in the third accommodating cavity 43a formed by the first connecting portion 43.

[0043] As another specific embodiment, referring to Figure 10 and Figure 11As shown, the housing 14 at least includes a receiving portion 41, a coupling portion 42, a first connection portion 43, and a second connection portion 44. The receiving portion 41 is formed with a first receiving cavity (not shown in the figure), and the first receiving cavity is used to receive the motor 13. The coupling portion 42 is used to couple the power supply device 17 to provide electrical energy for the operation of the motor 13. The first connection portion 43 connects the receiving portion 41 and the coupling portion 42 along a first path, and the first connection portion 43 is also provided with a handle 431 for the user to hold. The second connection portion 44 connects the receiving portion 41 and the coupling portion 42 along a second path. A through hole 45 is formed between the first connection portion 43 and the second connection portion 44, which enables the user's hand to easily pass through the through hole 45 when holding the handle 431. The housing 14 is also provided with an air inlet and an air outlet. Among them, at least a part of the air flow path that enters the housing 14 from the air inlet and flows out of the housing 14 from the air outlet is arranged on the second path.

[0044] Different from the above two embodiments, the circuit board 19 and the heat dissipation box 191 are disposed in a fourth receiving cavity 44a formed by the second connection portion 44, and the fourth receiving cavity 44a is disposed in the first channel 442. Refer to Figure 12 As shown, a first air inlet 421 is provided on a side of the second connection portion 44 away from the through hole 45, and the first air inlet 421 is located between the coupling portion 42 and the circuit board 19. Preferably, in order to improve the cooling effect, in the present utility model, a second air inlet 432 is disposed near the circuit board 19 and the heat dissipation box 191. It should be noted here that the technical solution in the present utility model does not limit the distance between the second air inlet 432 and the circuit board 19 and the heat dissipation box 191, and those skilled in the art can design it independently according to the actual use environment. In order to further enhance the ventilation effect, the first air inlet 421 is disposed on a side of the coupling portion 42 away from the first connection portion 43, and the third air inlet 411 is disposed on a side of the first connection portion 43 close to the receiving portion 41. When the fan 15 works, the air flow enters the housing 14 from the first air inlet 421, passes through the coupling portion 42, the first channel 442, the motor 13, and the air guide cover 46, and finally flows out from the air outlet 461 to form a first air path; the air flow enters the housing 14 from the second air inlet 432, passes through the first channel 442, the motor 13, and the air guide cover 46, and finally flows out from the air outlet 461 to form a second air path; the air flow enters the housing 14 from the third air inlet 411, passes through the motor 13 and the air guide cover 46, and finally flows out from the air outlet 461 to form a third air path. It should be noted here that since the circuit board 19 and the heat dissipation box 191 are disposed in the fourth receiving cavity 44a formed by the second connection portion 44, and the fourth receiving cavity 44a is disposed in the first channel 442, and the distance between the circuit board 19 and the heat dissipation box 191 and the fan 15 is closer compared with the above other embodiments, the technical solution proposed in this embodiment has a better heat dissipation effect.

[0045] In some other possible embodiments, the circuit board 19 and the heat dissipation box 191 can also be placed between the accommodating portion 41 and the fixed shield 18. The fan 15 is placed in the accommodating portion 41 and close to the side of the saw blade 12. An air inlet hole is provided on the side of the accommodating portion 41 away from the saw blade 12, and an air outlet 461 is provided on the fixed shield 18. Alternatively, the fan 15 can be placed in the accommodating portion 41 and away from the side of the saw blade 12. An air outlet hole is provided on the side of the accommodating portion 41 away from the saw blade 12, and an air inlet is provided on the fixed shield 18. Those skilled in the art can design independently according to the method in this embodiment, and no detailed introduction will be given here.

[0046] In some of the above embodiments, the circuit board 19 and the heat dissipation box 191 are fixedly connected together and can be arranged in the second accommodating cavity 42a formed by the joint portion 42 of the housing 14, or alternatively arranged in the fourth accommodating cavity 44a formed by the second connecting portion 44 and located in the first channel 442. At the same time, accessories such as switches, capacitor circuits, and wires are arranged in the third accommodating cavity 43a of the first connecting portion 43. It should be noted here that the third accommodating cavity 43a is preferably set as an independent accommodating cavity, and it can be further understood that most of the air flow does not flow through the third accommodating cavity 43a. In addition, for the position and quantity of the above air inlets, those skilled in the art can design independently according to actual design requirements.

[0047] In some other embodiments, the circuit board 19 and the heat dissipation box 191 are not arranged together and are placed separately in the housing 14. In this way, there is no heat dissipation box 191 at the position of the circuit board 19, so the occupied space is greatly reduced, and the overall structure of the machine can be made more compact. The above technical solutions will be introduced in detail below.

[0048] Refer to Figure 12 As shown, the housing 14 at least includes an accommodating portion 41, a joint portion 42, a first connecting portion 43, and a second connecting portion 44. The accommodating portion 41 forms a first accommodating cavity (not shown in the figure), and the first accommodating cavity is used to accommodate the motor 13. The joint portion 42 is used to combine with the power supply device 17 to provide electrical energy for the operation of the motor 13. The first connecting portion 43 connects the accommodating portion 41 and the joint portion 42 along a first path, and the first connecting portion 43 also provides a handle 431 for the user to hold. The second connecting portion 44 connects the accommodating portion 41 and the joint portion 42 along a second path. A through hole 45 is formed between the first connecting portion 43 and the second connecting portion 44, which enables the user's hand to easily pass through the through hole 45 when holding the handle 431. The housing 14 is also provided with an air inlet and an air outlet. Among them, at least a part of the air flow circulation path that enters the housing 14 from the air inlet and flows out of the housing 14 from the air outlet 461 is arranged on the second path.

[0049] Refer to Figure 12As shown, the heat dissipation box 191 is disposed within the first channel 442 formed by the second connection portion 44. A first air inlet 421 is provided on the second connection portion 44 and at the middle position between the joint portion 42 and the heat dissipation box 191. Preferably, in order to improve the cooling effect, in the present utility model, the first air inlet 421 is disposed near the heat dissipation box 191. It should be noted here that the technical solution in the present utility model does not limit the distance between the first air inlet 421 and the heat dissipation box 191, and those skilled in the art can make independent designs according to the actual use environment. An air outlet 461 is provided on the side of the air guide cover 46 away from the second connection portion 44. The circuit board 19 is disposed within the second accommodation cavity 42a formed within the joint portion 42. It should be noted here that since the second accommodation cavity 42a in this embodiment is only used to place the circuit board 19, the volume of the second accommodation cavity 42a in this embodiment is much smaller than that of the second accommodation cavity 42a in some of the above embodiments. The circuit board 19 placed within the second accommodation cavity 42a formed by the joint portion 42 is connected to the heat dissipation box 191 disposed within the first channel 442 through a medium with good heat conduction performance. Preferably, they are connected by a copper sheet. When the fan 15 operates, the air flow enters the housing 14 from the first air inlet 421, passes through the first channel 442, the motor 13, and the air guide cover 46, and finally flows out from the air outlet 461, forming a first air path. It should be noted here that the heat generated when the circuit board 19 operates can be effectively transferred to the heat dissipation box 191 through the copper sheet with better heat conduction effect. Since the heat dissipation box 191 is disposed within the first channel 442 of the second connection portion 44 and the heat dissipation box 191 is closer to the fan 15, it has a better heat dissipation effect.

[0050] When the hand-held circular saw 1 is operating, a cooling air flow is generated by the rotation of the fan 15. The air flow passes through the first air path to timely and effectively carry away the heat generated by parts such as the circuit board 19 and the motor 13 during operation, improving the heat dissipation efficiency of the circuit board 19 and the motor 13 during operation. Additionally, it should be noted here that accessories such as the switch, capacitor circuit, and wires in this embodiment do not require additional heat dissipation measures because the heat generated by themselves during operation is relatively small, and they are preferably disposed within the third accommodation cavity 43a formed by the first connection portion 43.

[0051] It should be noted that in the above technical solution of the present utility model, the circuit board 19 can be disposed not only within the joint portion 42, but also can be selectively disposed within the third accommodation cavity 43a formed by the first connection portion 43, or on the side of the first connection portion 43 close to the accommodation portion 41 or in other appropriate spaces of the housing 14. The air inlets and outlets on the housing 14 can also be set according to the actual situation.

[0052] In some other embodiments, the hand-held circular saw 1 further includes a gear box 20 which is fixed to the motor shaft 131. To increase the air volume and air speed at the air outlet 461, referring to Figure 13 and Figure 14 as shown, the first end face 201 of the gear box 20 is closely attached to the first end face 46a of the air guide cover 46. When the hand-held circular saw 1 is operating, after the air flow enters the housing 14 from the air inlet, when flowing through the air guide cover 46, according to the above technical solution, the air volume and air speed at the air outlet 461 can be maximally increased, ensuring that both the heat dissipation efficiency and the dust removal efficiency of the hand-held circular saw 1 during operation are improved.

[0053] It should be noted that the air path in all embodiments of the present utility model is not only used to blow the heat generated during the operation of the hand-held circular saw 1 out of the housing 14, but also can blow the dust in the air path and part of the dust near the air outlet 461. In some embodiments, to further improve the dust removal effect, referring to Figure 15 as shown, the flipping bracket 21 can be lifted to create a space 211 as the passage for the dust removal air to pass through after passing through the air outlet 461. Or a straight groove 211 is provided on the flipping bracket 21 as the passage for the dust removal air to pass through after passing through the air outlet 461. Specifically, after the air flow enters the housing 14 from the air inlet and finally flows out from the air outlet 461, while dissipating heat, it also blows out the dust in the air path. According to the above technical solution, the air flow obstruction caused by the flipping bracket 21 can be reduced, thereby improving the dust removal efficiency.

[0054] In some embodiments, the hand-held circular saw 1 further includes a fixed guard 18 which is at least arranged on the upper half of the saw 12 along the diameter direction of the saw blade. Referring to Figure 16 as shown, when the outer diameter of the saw blade 12 is set to be greater than or equal to 100 mm and less than or equal to 130 mm, the length of the bottom plate 16 in the front-back direction is less than 190 mm. Defining the bottom plate plane 16a of the bottom plate 16 as the reference plane, defining the distance from the highest point of the handle 431 of the hand-held circular saw 1 in the up-down direction to the reference plane as a, and defining the distance from the highest point of the fixed guard 18 in the up-down direction to the reference plane as b, setting the ratio of a to b to be greater than or equal to 1 and less than or equal to 1.5.

[0055] The above has shown and described the basic principles, main features and advantages of the present utility model. Those skilled in the art should understand that the above embodiments do not limit the present utility model in any form. Any technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present utility model.

Claims

1. A hand-held circular saw, comprising: a housing formed with a ventilation opening for air flow; an output shaft for mounting a saw blade, at least a part of the saw blade extending in a cutting plane; a motor for driving the output shaft to rotate; a base plate formed with a base plate plane for contacting a workpiece, the base plate plane at least partially extending in a front-rear direction; a fixed guard surrounding at least a part of the saw blade; characterized in that the housing comprises: a receiving portion formed with a first receiving cavity for receiving the motor; a coupling portion for coupling a power supply device; a first connecting portion connecting the receiving portion and the coupling portion along a first path, the first connecting portion further provided with a handle for a user to hold; a second connecting portion connecting the receiving portion and the coupling portion along a second path; wherein, a through hole is formed between the first connecting portion and the second connecting portion, the through hole is arranged for fingers of the user to pass through when holding the handle, and the size of the hand-held circular saw in a height direction perpendicular to the base plate plane is greater than or equal to 150 mm and less than or equal to 200 mm.

2. The hand-held circular saw according to claim 1, characterized in that , the size of the hand-held circular saw in a width direction perpendicular to the cutting plane is greater than or equal to 120 mm and less than or equal to 160 mm.

3. The hand-held circular saw according to claim 1, characterized in that, further comprising a circuit board, the circuit board being disposed in a second receiving cavity formed in the coupling portion.

4. The hand-held circular saw according to claim 1, characterized in that, the coupling portion is provided with a first air inlet.

5. The hand-held circular saw according to claim 1, characterized in that, the second connecting portion is provided with a second air inlet at an end close to the receiving portion.

6. The hand-held circular saw according to claim 1, characterized in that, the power supply device can be set to be detachably connected to the coupling portion.

7. The hand-held circular saw according to claim 1, characterized in that, further comprising: a fan; a wind guide cover, the wind guide cover being at least disposed radially outside the fan; a gear box, a first end face of the gear box close to the fan being set as a plane.

8. The hand-held circular saw according to claim 7, characterized in that, a first end face of the wind guide cover is in contact with the first end face of the gear box.

9. The hand-held circular saw according to claim 7, characterized in that, the wind guide cover is formed with an air outlet, the air outlet being located radially outside the fan.

10. The hand-held circular saw according to claim 1, characterized in that, further comprising a fixed guard, the fixed guard being at least disposed radially outside a part of the saw blade.

11. The hand-held circular saw according to claim 1, characterized in that, when the outer diameter of the saw blade is set to be greater than or equal to 100 mm and less than or equal to 130 mm, the length of the base plate in a first direction is less than 190 mm.

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