Work machine

Abstract

In the present invention, a head part is miniaturized. In an electric cutting tool 10, the driving force of a motor 30 is transmitted to a movable-side blade 60 by a transmission mechanism 40. In the transmission mechanism 40, a bevel gear 51, an intermediate gear 54, and a sector gear 58 are provided to a head part 70 so as to be capable of rotating about a lateral direction. The bevel gear 51 is rotated by the driving force of the motor 30, and the rotation of the bevel gear 51 is reduced and transmitted to the intermediate gear 54. The rotation of the intermediate gear 54 is reduced and transmitted to the sector gear 58. An axis line AL3 of the intermediate gear 54 and an axis line AL4 of the sector gear 58 are arranged at positions different from that of an axis line AL2 of the bevel gear 51 and are arranged at positions overlapping the bevel gear 51 as seen from the lateral direction. Thus, the bevel gear 51, the intermediate gear 54, and the sector gear 58 can be collectively arranged as seen from the lateral direction. As a result, the size of the head part 70 seen from the lateral direction can be reduced.

Description

Work equipment

[0001] The present invention relates to a work machine.

[0002] In the tool (working machine) described in Patent Document 1 below, a movable blade having a cutting blade is provided in a head portion, which is the tip portion of the tool. The head portion is provided with a transmission mechanism composed of a gear train, which reduces the driving force of the motor and transmits it to the movable blade. This transmits a high-torque driving force to the movable blade, allowing the rotating movable blade to cut the workpiece.

[0003] DE 3524443 A1

[0004] However, the above-mentioned tool has room for improvement in the following respects. That is, in the above-mentioned tool, the gear train constituting the transmission mechanism is arranged to extend in the front-rear direction, and the head part in which the transmission mechanism is arranged tends to be large. If the head part is large, for example, the distance between the workpiece and the worker increases, which may lead to a decrease in workability. Therefore, the above-mentioned tool has room for improvement in terms of making the head part smaller.

[0005] SUMMARY OF THE INVENTION In consideration of the above, an object of the present invention is to provide a work machine that can reduce the size of its head portion.

[0006] One or more embodiments of the present invention are a work machine comprising: a housing that accommodates a motor; a head portion provided on one side of the housing in a first direction and having a fixed blade that supports a workpiece; a movable blade provided on the head portion that rotates when activated to cut the workpiece; and a transmission mechanism that transmits power from the motor to the movable blade, wherein the transmission mechanism includes: a bevel gear to which the rotational force of the motor is transmitted and that rotates about an axis in a second direction that intersects the first direction; an intermediate gear to which the rotation of the bevel gear is transmitted at a reduced speed and that rotates about an axis in the second direction; and an output gear to which the rotation of the intermediate gear is transmitted at a reduced speed and that rotates about an axis in the second direction and that transmits the rotation of the second intermediate gear to the movable blade, wherein the bevel gear, the intermediate gear, and the output gear are provided in the head portion, and the axes of the intermediate gear and the output gear are positioned at positions different from the axis of the bevel gear and are positioned at positions that overlap with the bevel gear when viewed from the second direction.

[0007] One or more embodiments of the present invention are a work machine in which a direction perpendicular to the first direction and the second direction is a third direction, the axis of the intermediate gear is located on one side of the third direction relative to the axis of the bevel gear, and the axis of the output gear is located on the other side of the third direction relative to the axis of the bevel gear.

[0008] One or more embodiments of the present invention are directed to a work machine in which the axis of the output gear is located on one side of the axis of the intermediate gear in the first direction.

[0009] In one or more embodiments of the present invention, the intermediate gear is a two-stage gear having a large diameter gear portion to which the rotation of the bevel gear is input and a small diameter gear portion meshed with the output gear, and the work machine is such that more than half of the large diameter gear portion overlaps with the bevel gear when viewed from the second direction.

[0010] One or more embodiments of the present invention are directed to a work machine in which the output gear is a sector gear having a fan shape that rotates reciprocally within a predetermined angle.

[0011] In one or more embodiments of the present invention, the fixed side blade has a blade fixing portion fixed to the head portion and a support portion extending from the blade fixing portion to one side in the first direction and supporting the workpiece, and the blade fixing portion overlaps the bevel gear when viewed from the second direction.

[0012] One or more embodiments of the present invention are a work machine in which the housing has a handle portion extending in the first direction, the head portion is arranged on one side of the handle portion in the first direction, and the motor is arranged on the other side of the handle portion in the first direction, and the transmission mechanism has a first transmission mechanism portion including the bevel gear, the intermediate gear, and the output gear, a second transmission mechanism portion housed in the housing, arranged on the other side of the handle portion in the first direction, and which decelerates the rotation of the motor, and a transmission shaft which connects the first transmission mechanism portion and the second transmission mechanism portion and transmits the rotation of the motor decelerated by the second transmission mechanism portion to the first transmission mechanism portion.

[0013] One or more embodiments of the present invention are directed to a work machine in which the reduction ratio of the first transmission mechanism is greater than the reduction ratio of the second transmission mechanism.

[0014] In one or more embodiments of the present invention, the head portion is configured to include a base case that houses the bevel gear, and a gear cover that is assembled to the base case and covers the bevel gear from one side in the second direction, and one end of the transmission shaft is rotatably connected to the gear cover.

[0015] One or more embodiments of the present invention are a work machine in which the bevel gear is rotatably connected to the base case and the gear cover.

[0016] One or more embodiments of the present invention are a work machine in which a bevel gear shaft having a pinion is provided at the axial center of the bevel gear so as to rotate integrally therewith, the pinion is arranged on one side of the gear cover in the second direction, the head portion has a gear case provided on one side of the base case in the second direction, the gear case houses the pinion, the intermediate gear, and the output gear, and the intermediate gear and the output gear are rotatably supported by the gear cover and the gear case.

[0017] One or more embodiments of the present invention are directed to a work machine in which the fixed-side blade is disposed on one side of the gear case in the second direction and is fixed to the gear case.

[0018] One or more embodiments of the present invention are a work machine in which the head portion is provided with a sensor board having a sensor portion for detecting the rotational position of the output gear, and the sensor board is fixed to the gear case.

[0019] In one or more embodiments of the present invention, the output gear is provided with a magnet, the sensor unit is a Hall IC, and the work machine outputs an output value according to the magnetic flux density of the magnet.

[0020] One or more embodiments of the present invention are a work machine in which the sensor board is provided on one side of the gear case in the second direction, and the gear case separates the sensor board from the output gear.

[0021] One or more embodiments of the present invention are a work machine in which the head portion has a head cover provided on one side of the gear case in the second direction, and the head cover covers the sensor board from one side in the second direction.

[0022] One or more embodiments of the present invention are directed to a work machine in which the head cover is made of resin.

[0023] One or more embodiments of the present invention are a work machine in which an output gear shaft extending in the second direction is provided at the rotation center of the output gear so as to rotate integrally therewith, one end of the output gear shaft in the second direction protrudes from the gear case to one side in the second direction and is connected to the movable side blade so as to rotate integrally therewith, and the head cover is provided with a regulating portion that regulates movement of the movable side blade to one side in the second direction.

[0024] One or more embodiments of the present invention include a housing that accommodates a motor, a head unit that is provided on one side of the housing in a first direction and has a fixed blade that supports a workpiece, a movable blade that is provided on the head unit and rotates when activated to cut the workpiece, and a transmission mechanism that transmits power from the motor to the movable blade, wherein the transmission mechanism includes a first intermediate gear that receives the rotational force of the motor and rotates about an axis in a second direction perpendicular to the first direction, and a second intermediate gear that receives the rotation of the first intermediate gear at a reduced speed and rotates about an axis in the second direction. a second intermediate gear, and an output gear to which the rotation of the second intermediate gear is reduced and transmitted, rotating about an axis in the second direction, and transmitting the rotation of the second intermediate gear to the movable side blade; a direction perpendicular to the first direction and the second direction is a third direction, the axis of the second intermediate gear overlaps with the first intermediate gear in the first direction, the axis of the second intermediate gear is located on one side of the axis of the first intermediate gear in the third direction, and the axis of the output gear is located on the other side of the axis of the first intermediate gear in the third direction.

[0025] One or more embodiments of the present invention are directed to a work machine in which the output gear overlaps with the first intermediate gear when viewed from the second direction.

[0026] According to the work machine having the above configuration, the head portion can be made smaller.

[0027] 1 is a side view of the electric cutting tool according to the present embodiment, as viewed from the right side. It is a plan view of the electric cutting tool shown in FIG. 1, as viewed from above. It is a side view of the electric cutting tool shown in FIG. 1, as viewed from the right side, showing the interior of the electric cutting tool with the right housing member, head cover, and gear case omitted. It is a side view showing an enlarged view of the periphery of the head unit shown in FIG. 3. It is a side view showing the movable blade and sector gear shown in FIG. 4 rotated to the retracted position. It is a side view of the head unit shown in FIG. 1, as viewed from the right side, with the head cover removed. It is a cross-sectional view (cross-sectional view taken along line 7-7 in FIG. 3) seen from the bottom of the head unit shown in FIG. 3. It is a cross-sectional view (cross-sectional view taken along line 8-8 in FIG. 6) seen from diagonally below and behind, showing the meshing state between the sector gear of the head unit and the blade-side second pinion shown in FIG. 6. It is a side view showing a modified example of the present embodiment, showing the movable blade and sector gear in the cutting position. It is a side view showing the movable blade and sector gear shown in FIG. 9 rotated to the retracted position. FIG. 10 is a side view showing a state in which the sector gear has been rotated to a retracted position while the movable blade remains in the cutting position from the state shown in FIG. 9 .

[0028] An electric cutting tool 10 as a work machine according to this embodiment will be described below with reference to the drawings. Arrows UP, FR, and RH, as appropriate, in the drawings indicate the upper side, front side, and right side of the electric cutting tool 10, respectively. In the following description, when the terms "up / down," "front / rear," and "left / right" are used, they refer to the up / down direction, the front / rear direction, and the left / right direction of the electric cutting tool 10 unless otherwise specified. The front / rear direction corresponds to the first direction in the present invention, the left / right direction corresponds to the second direction in the present invention, and the up / down direction corresponds to the third direction in the present invention.

[0029] As shown in Fig. 5, the electric cutting tool 10 is an electric tool for cutting workpieces W, such as joist supports used in suspended ceilings of buildings. The workpieces W are formed in the shape of long columns, and are formed in a generally C-shape when viewed in the longitudinal direction. As shown in Figs. 1 to 3, the electric cutting tool 10 includes a housing 20, a motor 30, a transmission mechanism 40, a head unit 70, a blade position detection mechanism 90, and a controller 100.

[0030] (Regarding the housing 20) The housing 20 forms the outer shell of the power cutting tool 10 excluding the head portion 70, and extends in the front-to-rear direction as a whole. The housing 20 is composed of housing members 22L and 22R that are divided into two in the left-to-right direction, and the housing 20 is formed by assembling the housing members 22L and 22R to each other. The housing 20 is composed of a handle housing portion 20A that forms the front portion of the housing 20, and a motor housing portion 20B that forms the rear portion of the housing 20.

[0031] The handle housing 20A has a handle portion 20C that is gripped by the operator, and the handle portion 20C is formed into a cylindrical shape that extends in the front-to-rear direction. A handle end portion 20D is provided at the front end of the handle housing 20A, in front of the handle portion 20C, and the handle end portion 20D protrudes outward in the up-down direction beyond the handle portion 20C. A handle guard 20E is provided below the handle portion 20C, and the handle guard 20E is formed into a cylindrical shape that extends in the front-to-rear direction. The front end of the handle guard 20E is connected to the lower end of the handle end portion 20D, and the rear end of the handle guard 20E is bent upward and connected to the rear end of the handle portion 20C.

[0032] A trigger 24 is provided at the front end of the handle portion 20C. The trigger 24 protrudes downward from the handle portion 20C so as to be pulled upward. A trigger switch 26 is provided in front of the trigger 24 at the handle end portion 20D. When the trigger 24 is pulled, the trigger switch 26 is switched from OFF to ON. When the trigger 24 is released from being pulled, the trigger switch 26 is switched from ON to OFF. The trigger switch 26 is electrically connected to a controller 100 (described later) and outputs an output signal to the controller 100 in response to the pulling of the trigger 24. Specifically, a wire 26A extending downward from the trigger switch 26 is routed within the handle guard 20E and connected to the controller 100 housed in the motor housing portion 20B.

[0033] The motor housing 20B is formed in a generally flat shape with its thickness extending in the left-right direction, and the rear ends of the handle 20C and handle guard 20E are connected to the front end of the motor housing 20B. A battery mounting section 20G is provided at the rear end of the motor housing 20B. A battery 28 is detachably mounted on the upper side of the battery mounting section 20G. The battery 28 is electrically connected to a controller 100 (described later), and power is supplied to a motor 30 (described later) via the controller 100.

[0034] (Regarding the Motor 30) As shown in FIG. 3, the motor 30 is a brushless motor and is housed in the vertically central portion of the motor housing portion 20B. In other words, the motor 30 is disposed behind the handle portion 20C. The motor 30 has a motor shaft 30A whose axial direction is the front-to-rear direction. The rear end of the motor shaft 30A is rotatably supported by a motor bearing 32 held in the housing 20, and the front end of the motor shaft 30A is rotatably supported by a motor bearing 34 held in the housing 20. A motor-side pinion 36 is provided at the front end of the motor shaft 30A so as to rotate integrally therewith. The motor 30 is electrically connected to a controller 100 (described later) and is driven under the control of the controller 100.

[0035] (Regarding the transmission mechanism 40) The transmission mechanism 40 is a mechanism that transmits the driving force of the motor 30 to the movable blade 60, which will be described later. The transmission mechanism 40 is configured to include a motor-side transmission mechanism 41 serving as a second transmission mechanism housed in the motor housing portion 20B of the housing 20, a blade-side transmission mechanism 50 serving as a first transmission mechanism provided in the head portion 70, and a transmission shaft 45 that connects the motor-side transmission mechanism 41 and the blade-side transmission mechanism 50. The motor-side transmission mechanism 41 and the transmission shaft 45 will be described below, and the blade-side transmission mechanism 50 will be described later.

[0036] The motor-side transmission mechanism 41 is primarily composed of the motor-side pinion 36 and the motor-side reduction gear 42. The motor-side reduction gear 42 is held by a gear holder 43 for integral rotation. The gear holder 43 is formed in a generally stepped, bottomed cylindrical shape that is open to the front, and the diameter of the front portion of the gear holder 43 is set larger than the diameter of the rear portion of the gear holder 43. The motor-side reduction gear 42 is formed in a generally cylindrical shape with its axial direction extending in the front-to-rear direction. The front portion of the gear holder 43 is fitted into the motor-side reduction gear 42, and the motor-side reduction gear 42 is connected to the gear holder 43 for integral rotation. The motor-side reduction gear 42 is disposed above the front end of the motor shaft 30A of the motor 30, and the rear portion of the gear holder 43 is rotatably supported by a gear bearing 44 held in the housing 20. External teeth are formed on the outer periphery of the motor-side reduction gear 42, and these external teeth mesh with the motor-side pinion 36 of the motor shaft 30A. The outer diameter of the motor-side reduction gear 42 is set to be larger than the outer diameter of the motor-side pinion 36. This allows the motor-side transmission mechanism 41 to reduce the rotation of the motor 30. In this embodiment, the reduction ratio of the motor-side transmission mechanism 41 is set to 53 / 8 = 6.63.

[0037] The transmission shaft 45 is formed in a generally cylindrical shape with its axial direction extending in the front-to-rear direction. The transmission shaft 45 is housed in the handle portion 20C and is disposed in front of and coaxial with the motor-side reduction gear 42. The rear end of the transmission shaft 45 is inserted into the gear holder 43 and is coupled to the gear holder 43 so as to be rotatable therewith. The rear end of the transmission shaft 45 is rotatably supported by a bearing 46 held in the housing 20, in front of the motor-side reduction gear 42. As shown in FIG. 7 , the front end of the transmission shaft 45 protrudes forward from the housing 20. A bevel pinion 48 is provided at the front end of the transmission shaft 45 so as to be rotatable therewith. The bevel pinion 48 is rotatably supported by a bearing 47 held in the head portion 70, which will be described later. As a result, when the motor 30 is driven, the transmission shaft 45 rotates about an axis extending in the front-to-rear direction.

[0038] 1 to 8, the head portion 70 is disposed on the front side (one side in the front-to-rear direction) of the housing 20 and is located in front of the handle portion 20C. The head portion 70 includes a base case 72, a bevel gear cover 74 as a gear cover, a gear case 76, and a head cover 78.

[0039] The base case 72 is made of metal and is formed in a generally rectangular box shape that is open to the right (one side in the left-right direction). A case mounting portion 72A that protrudes rearward is provided at the edge of the rear opening of the base case 72. The case mounting portion 72A is disposed on the left side of the transmission shaft 45 within the handle end portion 20D of the housing 20 and is fastened together to the housing members 22L and 22R. A bearing recess 72B (see FIG. 7) that protrudes leftward is formed in the left wall of the base case 72. The bearing recess 72B is formed in a generally cylindrical shape with a bottom that is open to the right.

[0040] The bevel gear cover 74 is formed in a generally cylindrical shape with a bottom that is open to the left. The bevel gear cover 74 is housed in the base case 72, and the opening edge of the bevel gear cover 74 is fastened and fixed to the bottom wall (left wall) of the base case 72. A pinion accommodating portion 74A for accommodating the bevel pinion 48 of the transmission shaft 45 is formed in the rear end of the bevel gear cover 74. The pinion accommodating portion 74A is formed in a generally cylindrical shape with a bottom that is open to the rear, and is raised to the right from the right wall of the bevel gear cover 74. The interior of the pinion accommodating portion 74A is connected to the interior of the bevel gear cover 74. The front end of the transmission shaft 45 and the bevel pinion 48 are housed in the pinion accommodating portion 74A (see FIG. 7). A bearing 47 is held in the opening of the pinion accommodating portion 74A, and the bevel pinion 48 is rotatably supported by the bearing 47 (see FIG. 7). As a result, the front end of the transmission shaft 45 is rotatably connected to the bevel gear cover 74 via the bearing 47 and the bevel pinion 48 .

[0041] The gear case 76 is made of metal and has a generally rectangular box shape that is open to the left. The gear case 76 is a case for accommodating the blade-side first pinion 53, the intermediate gear 54, and the sector gear 58 of the blade-side transmission mechanism 50 (described later). The outer shape of the gear case 76 when viewed from the left and right generally matches the outer shape of the base case 72. The gear case 76 is fastened and fixed to the base case 72 by abutting the opening edge of the gear case 76 with the opening edge of the base case 72 in the left-right direction. A case mounting portion 76A (see FIG. 7 ) that protrudes rearward is provided at the rear opening edge of the gear case 76. The case mounting portion 76A is located to the right of the transmission shaft 45 within the handle end portion 20D of the housing 20 and is fastened together with the housing members 22L and 22R.

[0042] A gear accommodating portion 76B that accommodates a blade-side second pinion 56 and a sector gear 58 of the intermediate gear 54 (described later) is formed on the right wall of the gear case 76. The gear accommodating portion 76B is formed in a recessed shape that is open to the left and protrudes to the right from the gear case 76. A board accommodating portion 76C (see FIGS. 6 to 8) that accommodates a sensor board 94 (described later) is formed on the right surface of the gear accommodating portion 76B, and the board accommodating portion 76C is formed in a recessed shape that is open to the right.

[0043] The head cover 78 is made of resin and has a relatively shallow box shape that is open to the left. The outer shape of the head cover 78 when viewed from the left and right direction roughly matches the outer shape of the gear accommodating portion 76B of the gear case 76. The head cover 78 is disposed on the right side of the gear accommodating portion 76B and fastened and fixed to the gear accommodating portion 76B. As a result, the board accommodating portion 76C is covered from the right side by the head cover 78. Openings 78A (see FIGS. 7 and 8) are formed in the front and lower side walls of the head cover 78, and the interior of the head cover 78 is open to the front and bottom through the openings 78A.

[0044] The head unit 70 is provided with a fixed-side blade 80. The fixed-side blade 80 is made of a metal plate and has a generally rectangular plate shape with its thickness in the left-right direction and its length in the front-rear direction. The rear portion of the fixed-side blade 80 is a blade fixing portion 80A, which is disposed to the right of the gear housing portion 76B in the gear case 76. The blade fixing portion 80A is attached to a pin 82 (see FIGS. 4 and 5 ) fixed to the right wall of the gear housing portion 76B and fastened to the right wall of the gear housing portion 76B. The front portion of the fixed-side blade 80 is a support portion 80B, which protrudes forward from the head unit 70 (base case 72). Specifically, the blade fixing portion 80A is covered from the right side by the head cover 78, and the support portion 80B extends forward from an opening 78A of the head cover 78.

[0045] A support recess 80C is formed at the lower end of the support portion 80B, and is formed as a recess that is open downward when viewed from the left and right. A pair of front and rear slits 80D are formed through both front and rear ends of the bottom of the support recess 80C. The slits 80D are formed as grooves that extend in the vertical direction, and the slits 80D and the support recess 80C are connected. During cutting, the side walls of the workpiece W set in the support recess 80C are inserted into the slits 80D (see FIG. 5).

[0046] 3 to 8, the blade-side transmission mechanism 50 is provided in the head unit 70. The blade-side transmission mechanism 50 includes the bevel pinion 48, the bevel gear 51, the intermediate gear 54, and the sector gear 58 as an output gear.

[0047] As shown in Figures 4, 5, and 7, the bevel gear 51 is housed in the base case 72 with its axial direction aligned left-right, and is covered from the right side by a bevel gear cover 74. Specifically, the bevel gear 51 is positioned vertically so that the axis AL1 of the transmission shaft 45 and the axis AL2 of the bevel gear 51 intersect. A shaft portion 51A (see Figure 7) protruding leftward is provided at the axial center of the left surface of the bevel gear 51, and the shaft portion 51A is rotatably supported by a bearing 61 held in a bearing recess 72B of the base case 72. A bevel gear shaft 52 is provided at the axial center of the bevel gear 51 so as to rotate integrally therewith. The right end of the bevel gear 51 protrudes rightward from the bevel gear 51 and is rotatably supported by a metal bearing 62 held in the right wall of the bevel gear cover 74. As a result, the bevel gear 51 is connected to the base case 72 and the bevel gear cover 74 so as to be rotatable about its axial direction in the left-right direction.

[0048] The bevel pinion 48 of the transmission shaft 45 is disposed on the right side of the rear of the bevel gear 51, and the bevel pinion 48 and the bevel gear 51 are meshed together. The numbers of teeth of the bevel pinion 48 and the bevel gear 51 are set so that the rotation of the transmission shaft 45 is decelerated by the bevel pinion 48 and the bevel gear 51. In this embodiment, the reduction ratio, which is the ratio of the rotation speed of the bevel gear 51 to the rotation speed of the bevel pinion 48, is set to 37 / 11 = 3.36. In the head unit 70, the blade fixing portion 80A of the fixed-side blade 80 described above overlaps with the bevel gear 51 when viewed from the left-right direction.

[0049] A blade-side first pinion 53 serving as a pinion is provided at the right end of the bevel gear shaft 52. The blade-side first pinion 53 protrudes to the right from the bevel gear cover 74 and is housed in a gear case 76.

[0050] 4 to 8 , the intermediate gear 54 is a two-stage gear with its axial direction extending in the left-right direction. Specifically, the intermediate gear 54 has a blade-side reduction gear 55 as a large-diameter gear portion constituting the left portion of the intermediate gear 54, and a blade-side second pinion 56 as a small-diameter gear portion constituting the right portion of the intermediate gear 54. The outer diameter of the blade-side reduction gear 55 is set larger than the outer diameter of the blade-side second pinion 56. An intermediate gear shaft 57 is provided at the axial center of the intermediate gear 54, and the blade-side reduction gear 55 and the blade-side second pinion 56 are connected to the intermediate gear shaft 57 so as to be rotatable together.

[0051] The intermediate gear 54 is disposed on the right side of the bevel gear cover 74 and is housed in the gear case 76. The left end of the intermediate gear shaft 57 protrudes leftward from the blade-side reduction gear 55 and is rotatably supported by a metal bearing 63 (see FIG. 8) held on the right wall of the bevel gear cover 74. The right end of the intermediate gear shaft 57 protrudes rightward from the blade-side second pinion 56 and is rotatably supported by a metal bearing 64 (see FIG. 8) held on the right wall of the gear housing portion 76B of the gear case 76. As a result, the intermediate gear 54 is rotatably connected to the bevel gear cover 74 and the gear case 76 by the intermediate gear shaft 57 with the left-right direction as the axial direction.

[0052] The blade side reduction gear 55 is disposed radially outward of the blade side first pinion 53. Specifically, the blade side reduction gear 55 is disposed above (on one side in the up-down direction of) the blade side first pinion 53. That is, the axis AL3 of the intermediate gear 54 is disposed at a position different from the axis AL2 of the bevel gear 51. Furthermore, the axis AL3 of the intermediate gear 54 is disposed at a position overlapping the outer periphery of the bevel gear 51 when viewed from the left-right direction, and is located slightly forward of the axis AL2 of the bevel gear 51. The outer diameter of the blade side reduction gear 55 is set larger than the outer diameter of the blade side first pinion 53, and the blade side reduction gear 55 meshes with the blade side first pinion 53. As a result, the rotation of the bevel gear 51 is reduced in speed by the blade side first pinion 53 and the blade side reduction gear 55, and is transmitted to a sector gear 58, which will be described later. In this embodiment, the reduction ratio, which is the ratio of the rotation speed of the blade side reduction gear 55 to the rotation speed of the blade side first pinion 53, is set to 48 / 9 = 5.33. In addition, the position of the axis AL3 of the intermediate gear 54 is set so that more than half of the blade side reduction gear 55 overlaps with the bevel gear 51 when viewed from the left-right direction.

[0053] The sector gear 58 is a generally sector-shaped gear with its axis extending in the left-right direction. A spindle 59 serving as an output gear shaft is provided at the base end (rotation center) of the sector gear 58, and the sector gear 58 is connected to the spindle 59 so as to rotate integrally with it. The spindle 59 protrudes to both the left and right of the sector gear 58.

[0054] The sector gear 58 is housed in a gear case 76. The left end of the spindle 59 is rotatably supported by a metal bearing 65 (see FIG. 8 ) held on the right wall of the bevel gear cover 74. The right end of the spindle 59 is rotatably supported by a metal bearing 66 held on the right wall of a gear housing portion 76B in the gear case 76. As a result, the sector gear 58 is rotatably connected to the bevel gear cover 74 and the gear case 76 by the spindle 59, with the left-right direction being the axial direction. A connecting shaft 59A is provided at the right end of the spindle 59. The connecting shaft 59A has two parallel side surfaces and two curved surfaces connecting them, and is formed in a substantially elliptical shape when viewed in the axial direction. The connecting shaft 59A protrudes to the right from the gear case 76 and is disposed inside the head cover 78.

[0055] The axis AL4 of the spindle 59 (sector gear 58) is located below and forward of the axis AL2 of the bevel gear 51 when viewed from the left-right direction. That is, the axis AL4 of the spindle 59 (sector gear 58) is positioned differently from the axis AL2 of the bevel gear 51. Furthermore, the axis AL4 of the spindle 59 (sector gear 58) is positioned so as to overlap the outer periphery of the bevel gear 51 when viewed from the left-right direction, and is located forward of the axis AL3 of the intermediate gear 54. The sector gear 58 extends upward from its base end. A gear portion 58A is formed at the tip end of the sector gear 58, and the gear portion 58A is formed in an arc shape centered on the axis AL4 of the spindle 59. The gear portion 58A has external teeth that mesh with the blade-side second pinion 56. In this embodiment, the sector gear 58 is configured to rotate back and forth about the axis AL4 by being driven by the motor 30. Specifically, the sector gear 58 rotates between a cut position (the position shown in FIG. 4) and a retracted position (the position shown in FIG. 5) rotated downward from the cut position.

[0056] Furthermore, the radius of the gear portion 58A of the sector gear 58 is set to be larger than the radius of the blade-side second pinion 56. As a result, the rotation of the intermediate gear 54 is reduced by the blade-side second pinion 56 and the sector gear 58. In this embodiment, the reduction ratio, which is the ratio of the rotation speed of the sector gear 58 to the rotation speed of the blade-side second pinion 56, is set to 37 / 12 = 3.08. As described above, in this embodiment, the reduction ratio of the blade-side transmission mechanism 50 is set to 55.3, which is larger than the reduction ratio of the motor-side transmission mechanism 41.

[0057] A movable blade 60 is connected to the spindle 59 so as to be rotatable together with the spindle 59. This allows the movable blade 60 to rotate together with the sector gear 58 between a cutting position (the position shown in FIG. 4) and a retracted position (the position shown in FIG. 5) rotated downward from the cutting position. The movable blade 60 will be described below when it is positioned at the cutting position.

[0058] The movable blade 60 is formed in a generally rectangular plate shape with its thickness in the left-right direction and its length in the front-rear direction, and is disposed adjacent to and below the fixed blade 80 on the left side. A fitting hole 60A is formed through the rear end of the movable blade 60. The fitting hole 60A is formed by two parallel inner surfaces formed on the inner periphery of the movable blade 60 and two curved surfaces connecting them, and is generally elliptical in shape corresponding to the connecting shaft 59A of the spindle 59. The connecting shaft 59A is fitted into the fitting hole 60A, connecting the movable blade 60 to the spindle 59 so that the blade can rotate integrally with it. Specifically, the two parallel side surfaces of the connecting shaft 59A come into contact with the two parallel inner surfaces of the fitting hole 60A (engagement similar to that between a nut and a wrench), thereby transmitting the rotational force of the connecting shaft 59A to the movable blade 60. As a result, the movable blade 60 extends forward from the spindle 59, and the front portion of the movable blade 60 protrudes forward from the head portion 70. A cylindrical restricting portion 78B (see FIG. 8) protruding to the left is provided on the right wall of the head cover 78 described above. The connecting shaft portion 59A is disposed within the restricting portion 78B, and the restricting portion 78B is disposed adjacent to the right side of the movable blade 60. As a result, the restricting portion 78B restricts the movement of the movable blade 60 to the right, preventing the movable blade 60 from coming off the spindle 59.

[0059] A blade portion 60B protruding upward is formed at the front of the movable blade 60, and the blade portion 60B is configured as a single blade. When viewed from the left and right, the blade portion 60B is positioned so that it overlaps with the support recess 80C of the fixed blade 80. When the movable blade 60 is in the retracted position, the blade portion 60B is positioned below and spaced apart from the support portion 80B of the fixed blade 80. As a result, when the movable blade 60 is in the retracted position, the support recess 80C of the fixed blade 80 is opened, allowing the workpiece W to be set in the support recess 80C. Then, by rotating the movable blade 60 from the retracted position to the cutting position, the workpiece W is sandwiched between the movable blade 60 and the fixed blade 80, and the workpiece W is cut by the blade portion 60B.

[0060] 6, the blade position detection mechanism 90 includes a magnet 92 and a pair of sensor boards 94. The magnet 92 is formed in a generally cylindrical shape with its axis extending in the left-right direction, and is embedded in the outer periphery of the sector gear 58 and exposed from the right side surface of the sector gear 58.

[0061] The pair of sensor boards 94 are arranged with their thicknesses in the left-right direction, are housed in the board housing portion 76C of the gear case 76, and are fixed to the bottom surface of the board housing portion 76C. Specifically, one of the sensor boards 94 is arranged in a position facing the magnet 92 of the sector gear 58 in the cutting position across the right wall of the gear case 76 in the left-right direction. The other sensor board 94 is arranged in a position facing the magnet 92 of the sector gear 58 in the retracted position across the right wall of the gear case 76 in the left-right direction.

[0062] A Hall IC 96 serving as a sensor is provided on the right surface of the sensor board 94, and the Hall IC 96 is electrically connected to the controller 100. The Hall IC 96 detects the magnetic flux density of the magnets 92 facing each other in the left-right direction and outputs an output value (voltage value) corresponding to the detected magnetic flux density to the controller 100. That is, the Hall IC 96 outputs an output value (voltage value) corresponding to the distance from the magnet 92 in the facing direction. A wiring hole 76D is formed in the left-right direction at the lower rear corner of the board accommodating portion 76C of the gear case 76. Wiring (not shown) extending from the sensor board 94 is inserted through the wiring hole 76D and routed inside the gear case 76, and also extends from the head unit 70 to the housing 20, where it is routed inside the housing 20 and connected to the controller 100.

[0063] 2, the controller 100 is housed in the lower end of the motor housing portion 20B of the housing 20 and is held by the housing 20. The trigger switch 26, the motor 30, and a pair of Hall ICs 96 are electrically connected to the controller 100. The controller 100 detects the cutting position or the retracted position of the movable blade 60 according to the output values ​​of the pair of Hall ICs 96.

[0064] The controller 100 controls the drive of the motor 30 based on the output signal from the trigger switch 26. Specifically, when the trigger switch 26 switches from off to on when the moving blade 60 is in the cutting position, the controller 100 drives the motor 30 in the forward direction (rotates in a first rotation direction) to rotate the moving blade 60 to the retracted position. When the controller 100 detects the retracted position of the moving blade 60, it stops the drive of the motor 30. When the trigger switch 26 switches from off to on when the moving blade 60 is in the retracted position, the controller 100 drives the motor 30 in the reverse direction (rotates in a second rotation direction) to rotate the moving blade 60 to the cutting position. When the controller 100 detects the cutting position of the moving blade 60, it stops the drive of the motor 30. That is, when the controller 100 detects that the trigger switch 26 is turned on when the moving blade 60 is in the cutting position, it controls the motor 30 to move the moving blade 60 to the retracted position. Conversely, when the controller 100 detects that the trigger switch 26 is turned on when the moving blade 60 is in the retracted position, it controls the motor 30 to move the moving blade 60 to the cutting position. In other words, the position of the moving blade 60 can be changed by turning on the trigger switch 26 at the start and end of cutting. Note that when moving the moving blade 60 from the cutting position to the retracted position (or vice versa), the controller 100 may be controlled so that the movement is completed normally if the trigger switch 26 is kept turned on and so that the motor 30 stops if the trigger switch 26 is turned off midway. Alternatively, the controller 100 may be controlled so that the movement is completed even if the trigger switch 26 is turned on once to operate the moving blade 60 and then turned off. The former allows the motor 30 to be stopped quickly in the event of an unexpected incident, such as if a foreign object gets caught during operation, while the latter eliminates the need to keep the trigger switch 26 pressed. Alternatively, the former control may be applied only to movement from the retracted position to the cut position, and the latter control may be applied only to movement from the cut position to the retracted position.

[0065] (Operations and Effects) Next, operations and effects of the electric cutting tool 10 according to this embodiment will be described.

[0066] In the electric cutting tool 10 configured as described above, when the movable blade 60 is in the cutting position, the magnet 92 of the sector gear 58 is positioned opposite the Hall IC 96 on one of the sensor boards 94 in the left-right direction. This allows the controller 100 to detect the cutting position of the movable blade 60 based on the output value of one of the Hall ICs 96. When the trigger 24 is operated and the trigger switch 26 is turned on, the motor 30 is driven in the forward direction under the control of the controller 100. This activates the transmission mechanism 40, causing the movable blade 60 to rotate from the cutting position toward the retracted position.

[0067] When the movable blade 60 reaches the retracted position, the magnet 92 of the sector gear 58 is positioned opposite the Hall IC 96 on the other sensor board 94 in the left-right direction. This allows the controller 100 to detect the retracted position of the movable blade 60 based on the output value of the other Hall IC 96. When the controller 100 detects the retracted position of the movable blade 60, it stops driving the motor 30. In this state, the workpiece W is set in the support recess 80C of the fixed blade 80.

[0068] After the workpiece W is placed in the support recess 80C, the trigger 24 is operated to turn on the trigger switch 26, which drives the motor 30 in the reverse direction under the control of the controller 100. This activates the transmission mechanism 40, causing the movable blade 60 to rotate from the retracted position toward the cutting position. That is, the movable blade 60 approaches the workpiece W, and the workpiece W supported by the fixed blade 80 is sandwiched between the movable blade 60 and the fixed blade 80, thereby cutting the workpiece W. When the movable blade 60 reaches the cutting position, the magnet 92 of the sector gear 58 is positioned opposite the Hall IC 96 on one of the sensor boards 94 in the left-right direction. This allows the controller 100 to detect the cutting position of the movable blade 60 based on the output value of the Hall IC 96. When the controller 100 detects the cutting position of the movable blade 60, the controller 100 stops driving the motor 30, completing the cutting of the workpiece W.

[0069] As described above, in the electric cutting tool 10, the driving force of the motor 30 is transmitted to the movable blade 60 by the transmission mechanism 40. In the transmission mechanism 40, the bevel gear 51, the intermediate gear 54, and the sector gear 58 are mounted on the head unit 70 so as to be rotatable about an axis in the left-right direction. The driving force of the motor 30 rotates the bevel gear 51, and the rotation of the bevel gear 51 is decelerated and transmitted to the intermediate gear 54. The rotation of the intermediate gear 54 is also decelerated and transmitted to the sector gear 58. The axis AL3 of the intermediate gear 54 and the axis AL4 of the sector gear 58 are positioned at a different position from the axis AL2 of the bevel gear 51 and overlap with the bevel gear 51 when viewed from the left-right direction. This allows the bevel gear 51, the intermediate gear 54, and the sector gear 58 to be arranged together in the head unit 70 when viewed from the left-right direction. In other words, the layout area of ​​the bevel gear 51, the intermediate gear 54, and the sector gear 58 can be reduced in size when viewed from the left and right. As a result, the size of the head unit 70 can be reduced when viewed from the left and right. This effect is achieved by the bevel gear cover 74 of the head unit 70. In a conventional configuration without the bevel gear cover 74, the bearing is held by a part of the components that make up the outer shell (e.g., the base case 72 or the head cover 78). In this case, the shaft extends in the vertical direction at a position that does not overlap with the bevel gear 51, and therefore the axis cannot be aligned with the bevel gear 51. In this embodiment, by using the bevel gear cover 74, the axis AL3 of the intermediate gear 54 and the axis AL4 of the sector gear 58 can be aligned at a position that overlaps with the bevel gear 51 when viewed in the axial direction. Furthermore, by using the gear case 76, the intermediate gear shaft 57 and the fixed-side blade 80 can be arranged so that at least a portion of them overlap when viewed in the left-right direction.

[0070] Furthermore, the axis AL3 of the intermediate gear 54 is located above the axis AL2 of the bevel gear 51, and the axis AL4 of the sector gear 58 is located below the axis AL2 of the bevel gear 51. This allows the intermediate gear 54 and the sector gear 58 to be arranged in a balanced manner in the up-down direction relative to the bevel gear 51. In other words, this contributes to a reduction in the size of the head unit 70 in the front-to-rear direction compared to a configuration in which the intermediate gear 54 and the sector gear 58 are arranged on one or the other side in the up-down direction relative to the axis AL2 of the bevel gear 51.

[0071] In addition, the axis AL4 of the sector gear 58 is located forward of the axis AL3 of the intermediate gear 54. This allows the sector gear 58 to rotate within the region above the axis AL4 and the region below the axis AL3.

[0072] In addition, when viewed from the left-right direction, more than half of the blade-side reduction gear 55 overlaps with the bevel gear 51. This allows the intermediate gear 54 to be provided in the head portion 70 while reducing the area of ​​the intermediate gear 54 that protrudes from the bevel gear 51 when viewed from the left-right direction.

[0073] The sector gear 58 is a sector-shaped gear that rotates back and forth around the axis AL4. This allows the size of the blade-side transmission mechanism 50 to be made smaller when viewed from the left and right, as compared to when the sector gear 58 is formed in a disk shape, and ultimately allows the size of the head unit 70 to be made smaller.

[0074] Furthermore, the blade fixing portion 80A of the fixed-side blade 80 overlaps with the bevel gear 51 when viewed from the left-right direction, and the support portion 80B of the fixed-side blade 80 extends forward from the blade fixing portion 80A. This makes it possible to reduce the size of the head unit 70 including the fixed-side blade 80 compared to a configuration in which the blade fixing portion 80A is disposed in front of the bevel gear 51. Specifically, it is possible to reduce the size of the head unit 70 including the fixed-side blade 80 in the front-to-rear direction.

[0075] The transmission mechanism 40 is configured to include a motor-side transmission mechanism 41 housed in the housing 20 at the rear of the handle portion 20C, a blade-side transmission mechanism 50 provided in the head portion 70 at the front of the handle portion 20C, and a transmission shaft 45 connecting the motor-side transmission mechanism 41 and the blade-side transmission mechanism 50. This allows the transmission mechanism 40 to be arranged in a balanced manner on both front and rear sides of the handle portion 20C that is gripped by the operator. In other words, the transmission mechanism 40 can be distributed and arranged on both front and rear sides of the handle portion 20C. This contributes to improving operability for the operator gripping the handle portion 20C.

[0076] Furthermore, in the transmission mechanism 40, the reduction ratio of the blade-side transmission mechanism 50 is greater than that of the motor-side transmission mechanism 41. This allows the bevel gear 51 to be provided in the head unit 70 while preventing the bevel gear 51 from becoming larger in size. That is, for example, if the reduction ratio of the motor-side transmission mechanism 41 is greater than that of the blade-side transmission mechanism 50, a high-torque driving force is input to the bevel gear 51. Therefore, the strength of the bevel gear 51 needs to be increased so that the bevel gear 51 is not damaged by the input driving force. As a result, if the reduction ratio of the motor-side transmission mechanism 41 is greater than that of the blade-side transmission mechanism 50, the size of the bevel gear 51 may become larger. In contrast, in the present embodiment, the reduction ratio of the blade-side transmission mechanism 50 is set greater than that of the motor-side transmission mechanism 41. This prevents the driving force transmitted from the motor-side transmission mechanism 41 to the bevel gear 51 from becoming too high in torque. As a result, the bevel gear 51 can be provided on the head portion 70 while the physical size of the bevel gear 51 is set to an appropriate size.

[0077] Furthermore, in the transmission mechanism 40, the front end of the transmission shaft 45 is rotatably supported by a bearing 47 held in a bevel gear cover 74 of the head portion 70. The bevel gear cover 74 covers the bevel gear 51 from the right side and rotatably supports the bevel gear shaft 52. This makes it possible to rotatably support the front end of the transmission shaft 45 by utilizing the bevel gear cover 74 that covers the bevel gear 51.

[0078] In the head part 70, a gear case 76 that houses the blade-side first pinion 53, the intermediate gear 54, and the sector gear 58 is disposed on the right side of the base case 72, and the intermediate gear 54 and the sector gear 58 are rotatably supported by the gear case 76 and the bevel gear cover 74. This makes it possible to rotatably support the intermediate gear 54 and the sector gear 58 by utilizing the bevel gear cover 74 that covers the bevel gear 51.

[0079] Furthermore, the fixed-side blade 80 is disposed on the right side of the gear case 76 and fixed to the gear case 76. In other words, the fixed-side blade 80 is disposed outside the gear case 76 and fixed to the gear case 76. This makes it possible to prevent, for example, lubricant such as grease applied to the blade-side first pinion 53, the intermediate gear 54, and the sector gear 58 from splashing onto the fixed-side blade 80 that supports the workpiece W.

[0080] A sensor board 94 equipped with a Hall IC 96 is fixed to the gear case 76, and the Hall IC 96 outputs an output value corresponding to changes in the magnetic flux density of the magnet 92 provided on the sector gear 58. This allows the controller 100 to detect the cutting position or retracted position of the sector gear 58 (movable blade 60) according to the output value from the Hall IC 96. The Hall IC 96 is located in an area covered by the head cover 78, thereby improving dust resistance.

[0081] The sensor board 94 is provided on the right side of the gear case 76, and the right wall of the gear case 76 separates the sensor board 94 from the sector gear 58. This prevents, for example, lubricant such as grease applied to the sector gear 58 from scattering onto the sensor board 94. This improves the reliability of the blade position detection mechanism 90.

[0082] In the head unit 70, the head cover 78 is attached to the gear case 76 from the right side to cover the sensor board 94. This ensures that the head cover 78 can protect the sensor board 94.

[0083] Furthermore, the head cover 78 covers the blade fixing portion 80A of the fixed blade 80, the rear portion of the movable blade 60, and the spindle 59 from the right side. This allows the head cover 78 to improve the appearance of the head unit 70.

[0084] The head cover 78 is made of resin, which contributes to reducing the weight of the head portion 70.

[0085] The head cover 78 is also provided with a restricting portion 78B, which is disposed adjacent to the right side of the movable blade 60 and restricts the rightward movement of the movable blade 60. This makes it possible to maintain a good connection state of the movable blade 60 to the spindle 59.

[0086] Furthermore, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0087] For example, in the above embodiment, the sector gear 58 and the movable blade 60 are connected to each other so that they can rotate together, but they do not necessarily have to rotate together as a single unit as long as the rotational force of the sector gear 58 is transmitted to the movable blade 60 during cutting. Modifications thereof will be described below.

[0088] 9, 10 and 11 show modifications of the above embodiment, in which like reference numerals are used to denote like functions and their description will be omitted.

[0089] 9, 10, and 11, a movable blade 160 is attached to the connecting shaft 59A (spindle 59) in place of the movable blade 60 in a similar manner. That is, the fitting hole 160A of the movable blade 160 fits onto the connecting shaft 59A, and the head cover 78 prevents the movable blade 160 from coming off the connecting shaft 59A. Like the movable blade 60, the movable blade 160 is formed with its thickness extending in the left-right direction. The fitting hole 160A is formed through the rear end of the movable blade 160. In addition, a blade portion 160B is formed at the front of the movable blade 160, protruding upward, and the blade portion 160B is configured as a single edge.

[0090] The movable blade 160 is attached to the connecting shaft 59A (spindle 59) in a similar manner. That is, the fitting hole 160A of the movable blade 160 fits into the connecting shaft 59A, while the head cover 78 prevents the movable blade 160 from coming off the connecting shaft 59A.

[0091] While the fitting hole 60 has a shape similar to the outer shape of the connecting shaft 59A, the fitting hole 160A of the movable blade 160 has a different shape. The fitting hole 160A is formed by a curved (arc) portion with a diameter slightly larger than the diameter of the curved portion of the connecting shaft 59A and inwardly protruding portions (two locations) having a first surface 160C and a second surface 160D. A pair of first surfaces 160C and a pair of second surfaces 160D are formed. The pair of first surfaces 160C are parallel to each other. The pair of second surfaces 160D are also parallel to each other. Regarding each of the first surfaces 160C and second surfaces 160D, only one of the pair is shown in FIGS. 9 and 11 .

[0092] The movable blade 160 is rotatable relative to the connecting shaft 59A. Specifically, the movable blade 160 and the connecting shaft 59A are connected so as to be relatively movable between a relative position where the connecting shaft 59A contacts the first surface 160C and a relative position where the connecting shaft 59A contacts the second surface 160D.

[0093] One end of a coil spring 200 is connected to the movable blade 160. The other end of the coil spring 200 is connected to the gear case 76. The coil spring 200 applies a biasing force to the movable blade 160 in a direction (clockwise in FIG. 9) that returns the movable blade 160 to the retracted position.

[0094] The operation of the modified example during cutting operations will now be described. The transmission mechanism by which the spindle 59 rotates in response to the rotation of the motor 30 operates in the same manner as in the above-described embodiment, and therefore will not be described here. In the state shown in FIG. 9 (when the sector gear 58 and the movable blade 160 are in the cutting position), the movable blade 160 is strongly pulled by the extended coil spring 200, but the movement of the movable blade 160 is restricted by contact between the first surface 160C and the connecting shaft 59A. When the motor 30 is driven forward from the state shown in FIG. 9 , the sector gear 59 moves toward the retracted position, thereby rotating the connecting shaft 59A. This changes the contact position between the first surface 160C and the connecting shaft 59A, thereby changing the position at which rotation is restricted for the movable blade 160. Meanwhile, because the movable blade 160 is biased by the coil spring 200, the movable blade 160 also moves toward the retracted position, similar to the sector gear 59. When the sector gear 59 reaches the retracted position, the controller 100 stops the motor 30, which also stops the movement of the connecting shaft 59A. When the sector gear 59 is in the retracted position, the position of the connecting shaft 59A relative to the first surface 160C changes, allowing the movable blade 160 to move between the cutting position and the retracted position. The movable blade 160 receives a biasing force from the extended coil spring 200, and will remain in the retracted position unless it receives another biasing force. This results in the state shown in FIG. 10.

[0095] Next, the movement of the sector gear 58 from the retracted position to the cutting position, i.e., the movement during cutting, will be described. When the trigger switch 26 is turned on in the state shown in Figure 10, the motor 30 rotates in the reverse direction, causing the spindle 59 to rotate. When the spindle 59 rotates, the rotational force of the connecting shaft 59A is transmitted to the first surface 160C, which in turn transmits the rotational force to the movable blade 160. When the sector gear 58 advances to the cutting position, the controller 100 stops the motor 30, and the movable blade 160 stops at the cutting position. In this manner, the cutting operation can be performed.

[0096] Here, we will explain the operation when the movable blade 160 becomes locked in the cutting position in a modified example, such as when it gets caught in the material. As described above, the movable blade 160 is restored to the retracted position by the coil spring 200. Therefore, since the movable blade 160 is not unlocked by the biasing force of the coil spring 200, even if the motor 30 is driven in the forward direction from the state shown in FIG. 9, the sector gear 58 moves toward the retracted position, but the movable blade 160 does not move. Then, when the sector gear 58 reaches the retracted position, the controller 100 stops the motor 30. This state is shown in FIG. 11. When the state shown in FIG. 11 is reached, the operator can unlock the movable blade 160 by applying some force to the movable blade 160.

[0097] In the state shown in Figure 9, the movable blade 160 can move counterclockwise, so there is a possibility that the movable blade 160 may become locked in an excessively rotated state beyond the cutting position due to contact with something. The fitting hole 160 is provided with a second surface 160D. The second surface 160D is designed to be able to come into contact with the excessively rotated movable blade 160 as it moves from the cutting position to the retracted position. Therefore, the force of the motor 30 can return the excessively rotated movable blade 160 at least to the cutting position, and this can be used to assist in unlocking the movable blade 160.

[0098] According to this modified configuration, if the movable blade 160 is locked, it is possible to reduce the load on the motor 30 when moving the sector gear 58 from the cutting position to the retracted position. That is, in the case of the embodiment shown in Figures 4 and 5, if the motor 30 is rotated forward while the movable blade 160 is locked, an excessive current flows through the motor 30, which may result in a decrease in product life due to deterioration or damage, or a stoppage of work due to overheating, thereby deteriorating workability. However, the modified configuration makes it possible to reduce such problems.

[0099] As another modification, an additional member for transmitting power may be interposed between the connecting shaft (spindle) and the movable blade depending on the product layout or to adjust the cutting force. That is, when the power of the connecting shaft is transmitted to the movable blade, the center of rotation of the movable blade may be moved away from the housing, the direction of the rotation axis may be changed, the rotational motion may be converted into linear motion, or the speed may be reduced or increased as appropriate.

[0100] 10 Electric cutting tool (work machine), 20 Housing, 20C Handle portion, 40 Transmission mechanism, 41 Motor side transmission mechanism portion (second transmission mechanism portion), 45 Transmission shaft, 50 Blade side transmission mechanism portion (first transmission mechanism portion), 51 Bevel gear, 52 Bevel gear shaft, 53 Blade side first pinion (pinion), 54 Intermediate gear, 55 Blade side reduction gear (large diameter gear portion), 56 Blade side second pinion (small diameter gear portion), 58 Sector gear (output gear), 59 Spindle (output gear shaft), 60 Movable side blade, 70 Head portion, 72 Base case, 74 Bevel gear cover (gear cover), 76 Gear case, 78 Head cover, 78B Restriction portion, 80 Fixed side blade, 80A Blade fixing portion, 80B Support portion, 92 Magnet, 94 Sensor board, 96 Hall IC (sensor part), AL2 bevel gear axis, AL3 intermediate gear axis, AL4 output gear axis

Claims

1. A work machine comprising: a housing that accommodates a motor; a head portion provided on one side of the housing in a first direction and having a fixed blade that supports the workpiece; a movable blade provided on the head portion that rotates when activated to cut the workpiece; and a transmission mechanism that transmits the power of the motor to the movable blade, wherein the transmission mechanism includes: a bevel gear to which the rotational force of the motor is transmitted and which rotates around an axis in a second direction that intersects with the first direction; an intermediate gear to which the rotation of the bevel gear is transmitted at a reduced speed and transmitted and which rotates around an axis in the second direction; and an output gear to which the rotation of the intermediate gear is transmitted at a reduced speed and transmitted and which rotates around an axis in the second direction and transmits the rotation of the second intermediate gear to the movable blade, wherein the bevel gear, the intermediate gear, and the output gear are provided in the head portion, and the axes of the intermediate gear and the output gear are positioned at positions different from the axis of the bevel gear and are positioned so as to overlap with the bevel gear when viewed from the second direction.

2. A work machine as described in claim 1, wherein a direction perpendicular to the first direction and the second direction is defined as a third direction, the axis of the intermediate gear is located on one side of the third direction relative to the axis of the bevel gear, and the axis of the output gear is located on the other side of the third direction relative to the axis of the bevel gear.

3. A work machine according to claim 2, wherein the axis of said output gear is located on one side of the axis of said intermediate gear in said first direction.

4. The work machine according to claim 2, wherein the intermediate gear is a two-stage gear having a large diameter gear portion to which the rotation of the bevel gear is input and a small diameter gear portion meshed with the output gear, and wherein more than half of the large diameter gear portion overlaps with the bevel gear when viewed from the second direction.

5. A work machine according to claim 2, wherein the output gear is a sector gear having a fan shape that rotates reciprocally within a predetermined angle.

6. A work machine as described in claim 1, wherein the fixed blade has a blade fixing portion fixed to the head portion and a support portion extending from the blade fixing portion to one side in the first direction and supporting the workpiece, and when viewed from the second direction, the blade fixing portion overlaps the bevel gear.

7. A work machine as described in claim 1, wherein the housing has a handle portion extending in the first direction, the head portion being arranged on one side of the handle portion in the first direction, and the motor being arranged on the other side of the handle portion in the first direction, and the transmission mechanism has: a first transmission mechanism portion including the bevel gear, the intermediate gear, and the output gear; a second transmission mechanism portion housed in the housing, arranged on the other side of the handle portion in the first direction, and which decelerates the rotation of the motor; and a transmission shaft which connects the first transmission mechanism portion and the second transmission mechanism portion and transmits the rotation of the motor decelerated by the second transmission mechanism portion to the first transmission mechanism portion.

8. A work machine according to claim 7, wherein the reduction ratio of the first transmission mechanism is greater than the reduction ratio of the second transmission mechanism.

9. A work machine as described in claim 8, wherein the head portion includes a base case that houses the bevel gear, and a gear cover that is assembled to the base case and covers the bevel gear from one side in the second direction, and one end of the transmission shaft is rotatably connected to the gear cover.

10. A work machine according to claim 9, wherein the bevel gear is rotatably connected to the base case and the gear cover.

11. A work machine as described in claim 10, wherein a bevel gear shaft having a pinion is provided at the axial center of the bevel gear so as to rotate integrally therewith, the pinion being disposed on one side of the gear cover in the second direction, the head portion having a gear case provided on one side of the base case in the second direction, the gear case housing the pinion, the intermediate gear, and the output gear, and the intermediate gear and the output gear being rotatably supported by the gear cover and the gear case.

12. A work machine according to claim 11, wherein the fixed-side blade is disposed on one side of the gear case in the second direction and is fixed to the gear case.

13. A work machine as described in claim 12, wherein the head portion is provided with a sensor board having a sensor portion for detecting the rotational position of the output gear, and the sensor board is fixed to the gear case.

14. A work machine according to claim 13, wherein the output gear is provided with a magnet, and the sensor unit is a Hall IC that outputs an output value according to the magnetic flux density of the magnet.

15. A work machine according to claim 13, wherein the sensor board is provided on one side of the gear case in the second direction, and the gear case separates the sensor board from the output gear.

16. A work machine as described in claim 15, wherein the head portion has a head cover provided on one side of the gear case in the second direction, and the head cover covers the sensor board from one side in the second direction.

17. The work machine according to claim 16, wherein the head cover is made of resin.

18. A work machine as described in claim 16, wherein an output gear shaft extending in the second direction is provided at the rotation center of the output gear so as to rotate integrally therewith, one end of the output gear shaft in the second direction protrudes from the gear case to one side in the second direction and is connected to the movable side blade so as to rotate integrally therewith, and the head cover is provided with a regulating portion that regulates movement of the movable side blade to one side in the second direction.

19. A cutting tool comprising: a housing that accommodates a motor; a head portion provided on one side of the housing in a first direction and having a fixed blade that supports the workpiece; a movable blade that is provided on the head portion and rotates when activated to cut the workpiece; and a transmission mechanism that transmits the power of the motor to the movable blade, wherein the transmission mechanism includes: a first intermediate gear to which the rotational force of the motor is transmitted and which rotates about an axis in a second direction perpendicular to the first direction; a second intermediate gear to which the rotation of the first intermediate gear is transmitted at a reduced speed and which rotates about an axis in the second direction; and an output gear to which the rotation of the second intermediate gear is transmitted at a reduced speed and which rotates about an axis in the second direction and which transmits the rotation of the second intermediate gear to the movable blade; and a direction perpendicular to the first direction and the second direction is defined as a third direction, A work machine in which the axis of the second intermediate gear overlaps with the axis of the first intermediate gear in the first direction, the axis of the second intermediate gear is located on one side of the axis of the first intermediate gear in the third direction, and the axis of the output gear is located on the other side of the axis of the first intermediate gear in the third direction.

20. A work machine according to claim 19, wherein the output gear overlaps with the first intermediate gear when viewed from the second direction.

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