Reciprocating saw

Abstract

A reciprocating saw (1), comprising a housing (2), an electric motor (3) being provided in the housing (2), and the electric motor (3) having an electric motor shaft (30); an output shaft (5), which is driven by the electric motor (3) to perform reciprocation; a transmission assembly (4), which is connected to the output shaft (5) and the electric motor shaft (30); a gearbox (6), which is used for supporting the transmission assembly (4); and a fan (7), which is arranged between the electric motor (3) and the gearbox (6), a rear end of the gearbox (6) being provided with a mounting part (60) for being fixedly connected to the electric motor (3), the mounting part (60) comprising a first end face (61) that faces the fan (7) and a peripheral wall (62) that at least partially surrounds the fan (7), at least one air vent (63) being provided on the peripheral wall (62), the mounting part (60) of the gearbox (6) having a flow-guide structure, and an airflow formed by the fan (7) being guided by the flow-guide structure and, after flowing out from the air vent (63), flowing forward into a gap between the gearbox (6) and the housing (2) to cool the gearbox (6). A flow-guide structure can guide the direction of airflow of the fan (7), to prevent air turbulence and reduce loss of airflow, effectively cooling the gearbox (6).

Description

[0001] Reciprocating saw

[0002] TECHNICAL FIELD

[0003] The present invention relates to a cutting tool, in particular a reciprocating saw.

[0004] BACKGROUND OF THE INVENTION

[0005] A reciprocating saw is an electric tool that cuts with a reciprocating saw blade. An electric motor and a transmission assembly are mounted in a housing of the reciprocating saw, the electric motor being connected to the transmission assembly, and the transmission assembly being connected to a saw blade, so that the electric motor drives the saw blade to reciprocate, by means of the transmission assembly, to achieve cutting. The transmission assembly is mounted on a front end of the electric motor by means of a gearbox. A reciprocating saw in the prior art is normally provided with a cooling fan at the front end of the electric motor to blow air forward, so as to dissipate heat from the gearbox. However, air blown from the fan arranged at the front end of the electric motor is directly blown onto a radial end face of the gearbox straight ahead, and the air blown from the fan comes back after being obstructed straight ahead, scattering in all directions, resulting in disordered airflow, which cools the gearbox with lower efficiency.

[0006] Therefore, urgently needed is provision of a reciprocating saw that can effectively cool and dissipate heat from a gearbox.

[0007] SUMMARY OF THE INVENTION

[0008] The technical problem to be solved by the present invention is to provide a reciprocating saw that has a good heat dissipation effect.

[0009] To solve the above technical problem, the present invention uses the following solution: a reciprocating saw, comprising a housing, an electric motor being provided in the housing, and the electric motor having an electric motor shaft; an output shaft, which is driven by the electric motor to perform reciprocation; a transmission assembly, which is connected to the output shaft and the electric motor shaft; a gearbox, which is used for supporting the transmission assembly; and a fan, which is arranged between the electric motor and the gearbox, a rear end of the gearbox being provided with a mounting part for being fixedly connected to the electric motor, the mounting part comprising a first end face that faces the fan and a peripheral wall that at least partially surrounds the fan, at least one air vent being provided on the peripheral wall, the mounting part of the gearbox having a flow-guide structure, and an airflow formed by the fan being guided by the flowguide structure and, after flowing out from the air vent, flowing forward into a gap between the gearbox and the housing to cool the gearbox. By means of a flow-guide structure arranged on the mounting part, the direction of airflow of the fan is guided, to prevent air turbulence and reduce loss of airflow, effectively cooling the gearbox.

[0010] According to an embodiment of the present invention, the flow-guide structure comprises a front flow-guide face arranged on the first end face and / or a side flow-guide face arranged on the peripheral wall. By means of designing a flow-guide face at the rear of the gearbox and at the front of the fan, an airflow blown from the fan is guided to the air vent on the peripheral wall, and a good flow-guide effect is achieved without needing a complicated structural design.

[0011] The air vent comprises a first end that is downstream in a direction of rotation of the fan and a second end that is upstream in the direction of rotation of the fan, and the front flow-guide face is a first spiral face that extends in the direction of rotation of the fan with a gradually lowering height from the first end. That is, the highest point of the spiralshaped front flow-guide face is at a first end of the air vent, and the spiral-shaped front flow-guide face then extends away from the air vent in the direction of rotation of the fan, with the height thereof also gradually lowering; thus an airflow blown from the fan flows in a direction from the highest point of the first spiral face to the lowest point of the first spiral face, and then flows out from the air vent, so that the airflow does not produce turbulence at the mounting part of the gearbox, greatly reducing loss of airflow.

[0012] The centre of the first end face is provided with a mounting hole for the electric motor shaft to pass through, and the front flow-guide face extends to an inner periphery of the peripheral wall with a gradually lowering height radially from an outer periphery of the mounting hole. Thus, the front flow-guide face provided on the first end face that further extends radially not only guides an airflow to flow in the direction of rotation of the fan, but at the same time also guides the airflow radially from the centre to flow from the air vent on the peripheral wall, and further prevents the airflow from scattering to the mounting hole of the first end face, which is advantageous for increasing the flow efficiency of airflow and the amount of air flowing out.

[0013] The air vent comprises a first end that is downstream in a direction of rotation of the fan and a second end that is upstream in the direction of rotation of the fan, and the side flow-guide face is a second spiral face that extends in the direction of rotation of the fan with a gradually lowering height from the first end of the air vent. The arrangement of the side flow-guide face causes an airflow blown toward the peripheral wall to be better guided to the air vent.

[0014] According to a preferred embodiment of the present invention, the air vents may be two, three or four in number, arranged evenly on the peripheral wall. The arrangement of air vents depends on the structural design of the mounting part of the gearbox. For example, when there are two air vents, the air vents may be symmetrically arranged on an upper side and a lower side of the peripheral wall of the mounting part, which is advantageous for compact design of the gearbox in a horizontal direction, making gripping easy for a user.

[0015] According to a preferred embodiment of the present invention, the front flow-guide face extends from a first end of the air vent to a second end of an adjacent air vent in a direction of rotation of the fan. The side flow-guide face extends from the first end of the air vent to a first end of the adjacent air vent in the direction of rotation of the fan. The number of front flow-guide faces and / or side flow-guide faces and the number of air vents are adapted to each other; the front flow-guide faces and / or side flow-guide faces are essentially located between adjacent air vents, to obtain higher flow-guide efficiency.

[0016] The fan is an axial flow and centrifugal composite fan. When rotating, the composite fan first sucks in air from the rear, accelerating the air through blades, and then discharges air in both an axial direction in front thereof and in a centrifugal direction around the blades. A air inlet is provided on the housing at a position corresponding to the rear of the electric motor, and a air outlet is provided on the housing at a position where the output shaft connects to a saw blade. Thus, external air enters the housing from an air inlet at the rear of the electric motor under the effect of the fan, first cooling the electric motor, and then, through the fan, an airflow is blown toward the first end face of the gearbox, then guided through the flow guide mechanism to flow out from the air vent, and flows forward and into the gap between the gearbox and the housing to cool the gearbox, and finally is discharged from the air outlet. In such a reciprocating saw, the parts thereof can be effectively cooled by heat dissipation, improving the service life and user-friendliness of the reciprocating saw.

[0017] BRIEF DESCRIPTION OF THE DRAWINGS

[0018] A better understanding of the embodiments mentioned can be gained from the following detailed description with reference to the drawings. It is emphasized that various components are not necessarily drawn to scale. In fact, dimensions may be increased or decreased at will for the purpose of clear description. In the drawings, identical reference signs denote identical elements.

[0019] Fig. 1 is a sectional view of a reciprocating saw of the present invention with a battery pack removed;

[0020] Fig. 2 is a partial schematic drawing of a gearbox and an electric motor of the reciprocating saw of the present invention;

[0021] Fig. 3 is a partial schematic drawing of a mounting part of the gearbox of the reciprocating saw of the present invention.

[0022] DETAILED DESCRIPTION OF THE INVENTION

[0023] The reciprocating saw of the present invention is described below with reference to Figs. 1 - 3. The following description is merely exemplary, and does not limit the disclosed content of the present application or the applications or uses of the present invention. The terms "front", "rear", "above...", "below...", "left" and "right" in the present invention are used throughout this Description to define various components of the reciprocating saw when arranged in an orientation in which it is to be used, such as the orientation shown in Fig. 1.

[0024] With reference to Fig. 1 , the reciprocating saw 1 comprises: a housing 2, an electric motor 3, a transmission assembly 4, an output shaft 5, a gearbox 6 and a fan 7. The length of the housing 2 extends in a first direction, and the first direction may be a front- back direction shown in the figure. The electric motor 3 is mounted in the housing 2, and is provided with an electric motor shaft 30 that extends in the first direction. The transmission assembly 4 is mounted in the gearbox 6, and the transmission assembly 4 is connected to the output shaft 5 and the electric motor shaft 30, so that the output shaft 5 reciprocates under the drive of the electric motor 3; the output shaft 5 is connected to a cutting accessory such as a saw blade 10, and by means of reciprocation of the output shaft 5, the saw blade 10 is driven to reciprocate to realize a cutting function of the reciprocating saw.

[0025] The fan 7 is arranged in the housing 2, and is located between the electric motor 3 and the gearbox 6, and preferably, the fan 7 is an axial flow and centrifugal composite fan. When rotating, the composite fan first sucks in air from the rear, accelerating the air through blades, and then discharges air in both an axial direction in front thereof and in a centrifugal direction around the blades.

[0026] With reference to Figs. 2 and 3, a rear end of the gearbox 6 is provided with a mounting part 60 that is fixedly connected to the electric motor 3, and the mounting part 60 comprises a first end face 61 that faces the fan and a peripheral wall 62 that at least partially surrounds the fan 7. An outer periphery of the peripheral wall 62 is approximately square or round, to be suited for mounting in the housing 2. An inner periphery of the peripheral wall 62 is approximately round, to encircle outer edges of the blades of the fan 7. The peripheral wall 62 extends in the first direction; an end face of the peripheral wall 62 forms a mounting face, and several threaded holes are provided on the mounting face, so that the gearbox 6 may be connected to the electric motor 3 by means of fasteners that are mounted in the threaded holes. At least one air vent 63 is formed on the peripheral wall 62. The air vent 63 is essentially a slit that extends in a direction of rotation of the fan, and comprises a first end 631 that is located downstream in the direction of rotation of the fan and a second end 632 that is located upstream in the direction of rotation of the fan. Preferably, two air vents are symmetrically arranged on the peripheral wall 62; more preferably, two air vents are respectively arranged on an upper side and a lower side of the peripheral wall 62, which is advantageous for compact design of the gearbox 6 in a horizontal direction, making gripping easy for a user. It will be understood that the number of air vents may not only be one or two, but may also be three or four; it depends on the structural design of the gearbox 6 and the amount of air needed to cool the gearbox 6.

[0027] The mounting part 60 of the gearbox 6 is provided with a flow-guide structure, and an airflow formed by the fan 7 is guided by the flow-guide structure and, after flowing out from the air vent 63, flows forward into a gap between the gearbox and the housing to cool the gearbox. By means of a flow-guide structure arranged on the mounting part 60, the direction of airflow of the fan is guided, to prevent air turbulence and reduce loss of airflow, effectively cooling the gearbox 6.

[0028] The flow-guide structure comprises a front flow-guide face 64 arranged on the first end face 61 and / or a side flow-guide face 65 arranged on the peripheral wall 62. By means of designing a flow-guide face at the rear of the gearbox 6 and at the front of the fan 7, an airflow blown from the fan is guided to the air vent 63 on the peripheral wall 62, and a good flow-guide effect is achieved without needing a complicated structural design.

[0029] According to an embodiment of the present invention, the front flow-guide face 64 is a first spiral face that extends in the direction of rotation of the fan with a gradually lowering height from the first end 631 of the air vent 63. For example, in the embodiment shown in Fig. 2, when the fan 7 rotates clockwise, the highest point of the front flow-guide face 64 is at the first end 631 that belongs to the air vent 63 and is downstream thereof in the clockwise direction, and the front flow-guide face extends from this first end 631 in the direction of rotation of the fan, and the height thereof gradually reduces, wherein said height is the distance by which the front flow-guide face 64 is higher than the first end face 61. That is, the first spiral face formed by the front flow-guide face essentially extends vertically in the first direction, and the “height” of the front flow-guide face refers to the distance thereof from the first end face in the first direction. Thus, the highest point of the spiral-shaped front flow-guide face 64 is at a first end that belongs to the air vent and is downstream thereof in the direction of rotation of the fan, and the spiral-shaped front flow-guide face then extends away from the air vent in the direction of rotation of the fan, with the height thereof also gradually reducing; thus an airflow blown from the fan flows in a direction from the highest point of the first spiral face to the lowest point of the spiral face, and then flows out from the air vent 63, so that the airflow does not produce turbulence at the mounting part of the gearbox, greatly reducing loss of airflow.

[0030] Preferably, when the number of air vents is greater than one, the front flow-guide face 64 extends until the first end 631 of an adjacent air vent 63; that is, the lowest point of the front flow-guide face 64 is at the first end 631 that belongs to the next air vent 63 and is downstream thereof in the direction of rotation of the fan. The number of front flowguide faces is the same as the number of air vents, and adjacent front flow-guide faces 64 are connected to each other head-to-tail. The highest point of one front flow-guide face abuts the lowest point of a front flow-guide face adjacent thereto. Thus, a larger amount of air blown from the fan can be guided, flowing out evenly from the various air vents, and flowing forward into the gap between the gearbox 6 and the housing 2.

[0031] The centre of the first end face 61 is provided with a mounting hole 66 for the electric motor shaft to pass through, and the front flow-guide face 64 extends to an inner periphery of the peripheral wall 62 with a gradually lowering height radially from an outer periphery of the mounting hole 66. Thus, the front flow-guide face 64 not only guides an airflow to flow in the direction of rotation of the fan, but at the same time also guides the airflow radially from the centre to flow from the air vent on the peripheral wall, and further prevents the airflow from scattering to the mounting hole 66 of the first end face 61 , which is advantageous for increasing the flow efficiency of the airflow and the amount of air flowing out.

[0032] The side flow-guide face 65 is a second spiral face that extends in the direction of rotation of the fan with a gradually lowering height from the first end 631 that belongs to the at least one air vent and is located downstream thereof in the direction of rotation of the fan. Likewise, the highest point of the side flow-guide face 65 also starts at the first end 631 that belongs to the air vent and is located downstream thereof in the direction of rotation of the fan, and then the side flow-guide face extends with a gradually lowering height in a selected direction of the fan. This “height” refers to the distance by which a surface of the side flow-guide face 65 is higher than an inner side peripheral face of the peripheral wall. That is, the height of the side flow-guide face is a radial height of the side flow-guide face that gradually lowers. Preferably, when there is not just one said air vent 63, the lowest point of the side flow-guide face 65 extends to a second end 632 that belongs to an adjacent air vent and is located upstream in the direction of rotation of the fan. That is, the side flow-guide faces are arranged at intervals between the air vents; thus, following the direction of rotation of the fan, an airflow is guided from the highest point to flow from the lowest point, and then flows out from the air vent 63. The arrangement of the side flow-guide faces 65 causes an airflow blown toward the peripheral wall to be better guided to the air vents.

[0033] According to a preferred embodiment of the present invention, a air inlet 8 is provided on the housing 2 at a position corresponding to the rear of the electric motor 3, and a air outlet 9 is provided on the housing 2 at a position where the output shaft 5 connects to a saw blade 10. The gearbox 6 is also arranged in the housing 2, and a gap is retained between the housing 2 and the gearbox 6. Thus, external air enters the housing 2 from the air inlet 8 at the rear of the electric motor under the effect of the fan 7, first cooling the electric motor 3, and then, through the fan 7, an airflow is blown toward the first end face 61 of the gearbox 6, and passing the front flow-guide face 64 and / or the side flowguide face 65, flows out from the air vent 63, continues to flow forward and into the gap between the gearbox 6 and the housing 2 to cool the gearbox 6, and finally is discharged from the air outlet 9, cooling the gearbox well. In such a reciprocating saw, the electric motor and the gearbox can both be effectively cooled by heat dissipation, improving the service life and user-friendliness of the reciprocating saw.

[0034] As stated above, although exemplary embodiments of the present invention have been explained herein with reference to the drawings, the present invention is not limited to the specific embodiments described above, and may have many other embodiments. The scope of the present invention should be defined by the claims and their equivalent meaning.

Claims

PATENT CLAIMS1. Reciprocating saw (1), comprising a housing (2), an electric motor (3) being provided in the housing (2), and the electric motor (3) having an electric motor shaft (30); an output shaft (5), which is driven by the electric motor (3) to perform reciprocation; a transmission assembly (4), which is connected to the output shaft (5) and the electric motor shaft (30); a gearbox (6), which is used for supporting the transmission assembly (4) ; a fan (7), which is arranged between the electric motor (3) and the gearbox (6), a rear end of the gearbox (6) being provided with a mounting part (60) for being fixedly connected to the electric motor (3), the mounting part (60) comprising a first end face (61)that faces the fan (7) and a peripheral wall (62) that at least partially surrounds the fan (7), and at least one air vent (63) being provided on the peripheral wall (62), characterized in that the mounting part (60) of the gearbox (6) is provided with a flow-guide structure, and an airflow formed by the fan (7) is guided by the flow-guide structure and, after flowing out from the air vent (63), flows forward into a gap between the gearbox (6) and the housing (2) to cool the gearbox (6).

2. Reciprocating saw (1) according to Claim 1 , characterized in that the flow-guide structure comprises a front flow-guide face (64) arranged on the first end face (61) and / or a side flow-guide face (65) arranged on the peripheral wall (62).

3. Reciprocating saw (1) according to Claim 2, characterized in that the air vent (63) comprises a first end (631) that is located downstream in a direction of rotation of the fan (7) and a second end (632) that is located upstream in the direction of rotation of the fan (7), and the front flow-guide face (64) is a first spiral face that extends in the direction of rotation of the fan (7) with a gradually lowering height from the first end (631).

4. Reciprocating saw (1) according to Claim 3, characterized in that the centre of the first end face (61) is provided with a mounting hole (66) for the electric motor shaft (30) to pass through, and the front flow-guide face (64) extends to an inner periphery of the peripheral wall (62) with a gradually lowering height radially from an outer periphery of the mounting hole (66).

5. Reciprocating saw (1) according to Claim 2, characterized in that the air vent (63) comprises a first end (631) that is located downstream in a direction of rotation of the fan(7) and a second end (632) that is located upstream in the direction of rotation of the fan (7), and the side flow-guide face (65) is a second spiral face that extends in the direction of rotation of the fan (7) with a gradually lowering height from the first end (631) of the air vent (63).

6. Reciprocating saw (1) according to any one of Claims 1 - 5, characterized in that two, three or four said air vents (63) are provided, separated evenly on the peripheral wall (62).

7. Reciprocating saw (1) according to Claim 6, characterized in that the front flow-guide face (64) extends from a first end (631) of the air vent (63) to a second end (632) of an adjacent air vent (63) in a direction of rotation of the fan (7).

8. Reciprocating saw (1) according to Claim 6, characterized in that the side flow-guide face (65) extends from a first end (631) of the air vent (63) to a first end (631) of an adjacent air vent (63) in a direction of rotation of the fan (7).

9. Reciprocating saw (1) according to any one of Claims 1 - 8, characterized in that an air inlet (8) is provided on the housing (2) at a position corresponding to the rear of the electric motor (3), and an air outlet (9) is provided on the housing (2) at a position where the output shaft (5) connects to a saw blade (10).

10. Reciprocating saw (1) according to any one of Claims 1 - 9, characterized in that the fan (7) is an axial flow and centrifugal composite fan (7).

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