Electric work machine

Abstract

To provide a technology which enables downsizing of an electric work machine with respect to a rotation axis direction of an output shaft.SOLUTION: An electric work machine disclosed by the specification includes: a rotary blade; an output shaft to which the rotary blade is attached; an output pulley fixed to the output shaft; an input shaft; an input pulley fixed to the input shaft; a transmission belt which is wound around the input pulley and the output pulley while spanning a space therebetween; an electric motor which has a motor shaft and rotationally drives the motor shaft; a speed reducer which reduces a speed of rotation of the motor shaft and transmits the rotation to the input shaft; and a housing which houses the electric motor and the speed reducer and rotatably supports the input shaft and the output shaft. A rotation axis of the motor shaft is arranged inclining relative to a direction along a rotation axis of the output shaft.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to an electric work machine. [Background technology]

[0002] Patent Document 1 discloses an electric working machine having a rotary blade, an output shaft to which the rotary blade is attached, an output pulley fixed to the output shaft, an input shaft, an input pulley fixed to the input shaft, a transmission belt stretched between the input pulley and the output pulley, and a motor shaft, an electric motor that rotates and drives the motor shaft, a reducer that reduces the rotation of the motor shaft and transmits it to the input shaft, and a housing that accommodates the electric motor and the reducer and rotatably supports the input shaft and the output shaft. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-43475 A Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional electric working machines, as in Patent Document 1, the rotation axis of the motor shaft is arranged in a direction parallel to the rotation axis of the output shaft. Generally, the longitudinal direction of an electric motor coincides with the direction of the rotation axis of the motor shaft, so in conventional electric working machines, the longitudinal direction of the electric motor is arranged in a direction parallel to the rotation axis of the output shaft. For this reason, it has not been possible to reduce the size of the electric working machine in the direction of the rotation axis of the output shaft (the axis of the rotary blade). This specification provides technology that makes it possible to reduce the size of an electric working machine in the direction of the rotation axis of the output shaft. [Means for solving the problem]

[0005] The electric working machine disclosed in this specification includes a rotary blade, an output shaft to which the rotary blade is attached, an output pulley fixed to the output shaft, an input shaft, an input pulley fixed to the input shaft, a transmission belt stretched between the input pulley and the output pulley, and a motor shaft, and further includes an electric motor that rotates the motor shaft, a reducer that reduces the rotation of the motor shaft and transmits it to the input shaft, and a housing that accommodates the electric motor and the reducer and rotatably supports the input shaft and the output shaft. The rotation axis of the motor shaft is arranged at an angle with respect to the direction along the rotation axis of the output shaft.

[0006] According to the above configuration, the longitudinal direction of the electric motor is inclined relative to the direction along the rotation axis of the output shaft, which makes it possible to reduce the size of the electric working machine in the direction of the rotation axis of the output shaft. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is an overall perspective view of a power cutter 10 according to an embodiment, as viewed from above on the front right. [Figure 2] 1 is a side view of the internal structure of a housing 14 of a power cutter 10 according to an embodiment, as viewed from the right. [Figure 3] 3 is a diagram showing the electric motor 4, the power transmission unit 8, and the rotary blade 12 in the power cutter 10 according to the embodiment, which are arranged as shown in FIG. 2. FIG. [Figure 4] 1 is a diagram showing the positional relationship between an electric motor 4, a rotary blade 12, a battery interface 24, and a plurality of battery packs 60 when the power cutter 10 according to the embodiment is viewed from the rear. FIG. [Figure 5] 1 is an enlarged view of a rear handle 20 provided on the power cutter 10 according to the embodiment, viewed from the upper rear left side. [Figure 6] 1 is a top view showing the center of gravity GT of the power cutter 10 according to the embodiment. FIG. [Figure 7]10 is an enlarged view showing a mechanism for preventing a transmission belt 83 from falling off in the power cutter 10 according to the embodiment, and showing a state in which the rotation of the output shaft 85 is permitted by the lock mechanism of the output shaft 85. FIG. [Figure 8] FIG. 2 is an exploded view of an output pulley 84 provided in the power cutter 10 according to the embodiment. [Figure 9] 10 is an enlarged view showing a mechanism for preventing a transmission belt 83 from falling off in the power cutter 10 according to the embodiment, and showing a state in which the rotation of the output shaft 85 is prohibited by a lock mechanism for the output shaft 85. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] Representative, non-limiting embodiments of the present invention are described in detail below with reference to the drawings. This detailed description is intended simply to provide those skilled in the art with details for implementing preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Furthermore, the additional features and inventions disclosed can be used separately or in conjunction with other features and inventions to provide further improved electric power implements.

[0009] Furthermore, the combinations of features and steps disclosed in the following detailed description are not essential to practicing the invention in its broadest sense, but are described solely to specifically illustrate exemplary embodiments of the invention. Furthermore, the various features of the following exemplary embodiments and those described in the claims do not necessarily have to be combined in the exact embodiments described herein or in the exact order listed to provide additional and useful embodiments of the invention.

[0010] All features described in this specification and / or claims are intended to be disclosed individually and independently of one another as limitations to the specific features described in the original disclosure and claims, apart from the configuration of features described in the examples and / or claims. Furthermore, all numerical ranges and group or aggregate descriptions are intended to disclose intermediate configurations thereof as limitations to the specific features described in the original disclosure and claims.

[0011] In one or more embodiments, the rotational axis of the motor shaft may be oriented perpendicular to the direction along the rotational axis of the output shaft.

[0012] According to the above configuration, the electric motor is arranged so that its longitudinal direction is substantially perpendicular to the rotation axis of the output shaft, which allows the electric working machine to be made smaller in size in the direction of the rotation axis of the output shaft (the axial direction of the rotary blade).

[0013] In one or more embodiments, when the electric operating machine is placed on a mounting surface, the rotation axis of the output shaft may be disposed along the left-right direction near the front end of the housing, and when the electric operating machine is viewed from the side, the rotation axis of the motor shaft may be disposed at an inclination angle with respect to the up-down direction within a range of −45° to 45°. Note that in this specification, the inclination angle of the rotation axis of the motor shaft with respect to the up-down direction will be described with a clockwise angle being a positive angle and a counterclockwise angle being a negative angle when the electric operating machine is viewed from the right.

[0014] According to the above configuration, when the electric operating machine is placed on the placement surface, the electric operating machine can be made smaller in size in the left-right direction and also in the front-rear direction.

[0015] In one or more embodiments, when the electric working machine is placed on the loading surface and viewed from the side, the rotation axis of the motor shaft may be inclined in the vertical direction so that it moves from rear to front as it moves from top to bottom.

[0016] According to the above configuration, when a user uses the electric tool with the rotary blade facing downward, the rotation axis of the motor shaft is likely to be aligned vertically. Therefore, when a user uses the electric tool with the rotary blade facing downward, the electric tool can be made smaller in the front-to-rear direction, thereby improving operability for the user.

[0017] In one or more embodiments, when the electric working machine is viewed from the side, the rotation axis of the motor shaft may be arranged to be approximately perpendicular to a line passing through the rotation axis of the output shaft and the rotation axis of the input shaft.

[0018] According to the above configuration, the rotation axis of the motor shaft is arranged approximately perpendicular to the radial direction of the rotary blade (i.e., approximately parallel to the tangential direction of the rotary blade). In other words, the longitudinal direction of the electric motor is arranged approximately perpendicular to the radial direction of the rotary blade (i.e., approximately parallel to the tangential direction of the rotary blade). According to the above configuration, the electric working machine can be made smaller in size in the radial direction of the rotary blade.

[0019] In one or more embodiments, the electric working machine may further include a first handle provided on the housing and held by one hand of a user, and a second handle provided on the housing and held by the other hand of the user. When the electric working machine is placed on the placement surface, the first handle may be located rearward of the rotary blade and forward of the electric motor, and the second handle may be located rearward of the electric motor.

[0020] Typically, the closer the center of gravity of an electric work machine is to the center of gravity of the user's body, the better the user's operability. Furthermore, since the electric motor is relatively heavy among the components of an electric work machine, the center of gravity of the electric work machine can change significantly depending on where the electric motor is located. According to the above configuration, the electric motor is located between the first handle and the second handle, so when a user uses the electric work machine by holding the first handle and the second handle, the center of gravity of the electric work machine is likely to be located close to the center of gravity of the user's body. This further improves user operability.

[0021] In one or more embodiments, the vehicle may further include at least one battery pack removably attached to the housing and configured to power the electric motor.

[0022] When an electric work machine is driven by power from an external power source, it is necessary to attach a power cord to the electric work machine, which can lead to reduced operability. With the above configuration, there is no need to attach a power cord to the electric work machine, which further improves operability for the user. In addition, the electric work machine can be used even in places where an external power supply is not available, which improves user convenience.

[0023] In one or more embodiments, when the electric working machine is placed on the mounting surface, the at least one battery pack may be positioned rearward of the electric motor and forward of the second handle.

[0024] Among the components of an electric work machine, the battery pack is relatively heavy, so the position of the center of gravity of the electric work machine changes significantly depending on where the battery pack is located. According to the above configuration, at least one battery pack is located between the first handle and the second handle, so when a user uses the electric work machine by holding the first handle and the second handle, the position of the center of gravity of the electric work machine is likely to be located close to the position of the center of gravity of the user's body. This further improves user operability.

[0025] In one or more embodiments, when the electric working machine is placed on the mounting surface, the battery pack and the electric motor may at least partially overlap when viewed from behind.

[0026] According to the above configuration, the electric motor and the battery pack are disposed close to each other in the left-right direction and the up-down direction, and therefore, when the electric working machine is placed on the mounting surface, the electric working machine can be made smaller in size in the left-right direction and also in the up-down direction.

[0027] In one or more embodiments, when the electric working machine is placed on the mounting surface, the rotary blade and the electric motor may at least partially overlap when viewed from behind.

[0028] According to the above configuration, the rotary blade and the electric motor are arranged close to each other in the left-right direction and the up-down direction, and when the electric working machine is placed on the mounting surface, the electric working machine can be made smaller in both the left-right direction and the up-down direction.

[0029] In one or more embodiments, the output pulley includes a first rotating member and a second rotating member fixed adjacent to the first rotating member in the rotational axis direction of the output shaft. The first rotating member includes a first cylindrical portion around which the transmission belt is wound and a flange portion extending radially outward from an end of the first cylindrical portion not adjacent to the second rotating member. The second rotating member includes a second cylindrical portion having an outer diameter larger than that of the first cylindrical portion and a base portion extending radially inward from an end of the second cylindrical portion adjacent to the first rotating member. The second cylindrical portion includes a plurality of lock holes formed at predetermined intervals in the circumferential direction. The electric operating machine further includes lock pins movably held in the housing and insertable into the plurality of lock holes.

[0030] When a seamless, integrally formed output pulley is provided with a mechanism for preventing the transmission belt from falling off and a mechanism for locking the rotation of the output shaft, the output pulley is formed into a complex shape. This can make it difficult to install the output pulley when assembling the electric power tool. According to the above configuration, the output pulley is composed of a first rotating member and a second rotating member. Therefore, when assembling the electric power tool, the first rotating member and the second rotating member are separately installed, which makes it easy to install the output pulley. Furthermore, according to the above configuration, when the transmission belt wound around the first cylindrical portion moves in the rotational axis direction of the output shaft, it is locked by the flange portion of the first rotating member or the base portion of the second rotating member. Therefore, the transmission belt is prevented from falling off the first cylindrical portion. Furthermore, according to the above configuration, when the lock pin is inserted into one of the multiple lock holes, if the output pulley rotates relative to the housing, the second rotating member is locked by the lock pin. Therefore, by inserting the lock pin into one of the multiple lock holes, the rotation of the output shaft can be locked.

[0031] In one or more embodiments, the first cylindrical portion and the flange portion are formed as a single piece without a seam. The second cylindrical portion and the base portion are formed as a single piece without a seam. The first rotating member is made of an aluminum alloy. The second rotating member is made of iron.

[0032] Because the output pulley is a member that rotates together with the output shaft, it is desirable to use a material with a small mass for the output pulley. On the other hand, considering that a lock pin is inserted into the output pulley to lock the rotation of the output shaft, it is desirable to use a material with high rigidity and strength for the output pulley. According to the above configuration, the necessary rigidity and strength are ensured by using iron for the second rotating member into which the lock pin is inserted, while the weight of the entire output pulley can be reduced by using an aluminum alloy for the first rotating member around which the transmission belt is wound.

[0033] (Example) (Configuration of Power Cutter 10) As shown in FIG. 1, a power cutter 10, an example of an electric power tool, is a handheld power tool primarily used to cut materials such as stone and iron. The power cutter 10 includes a rotary blade 12, a housing main body 14a, a blade arm 14b, a blade cover 16, a front handle 18, a rear handle 20, a water supply hose 50, a right battery pack 60a, a left battery pack 60b, and a guide roller 70. In this specification, the right battery pack 60a and the left battery pack 60b may be collectively referred to as "multiple battery packs 60." The housing main body 14a and the blade arm 14b may be collectively referred to as "housing 14."

[0034] As shown in FIG. 2, the power cutter 10 further includes an electric motor 4, a control board 6, a battery interface 24, and a power transmission unit 8.

[0035] (Rotary blade 12) The rotary blade 12 is a disk-shaped blade having multiple cutting edges or grinding wheels on its outer periphery. The rotary blade 12 may be, for example, a diamond wheel. The rotary blade 12 is a so-called consumable item, and is therefore detachably attached to the blade arm 14b. The rotation axis of the rotary blade 12 extends in a direction perpendicular to the longitudinal direction of the blade arm 14b.

[0036] Here, in this specification, when the power cutter 10 is placed on the placing surface H, the direction perpendicular to the placing surface H is defined as the up-down direction, the direction in which the power cutter 10 is placed on the placing surface H is defined as the up-down direction, and the direction from the power cutter 10 toward the placing surface H is defined as the down-down direction. Furthermore, the direction perpendicular to the up-down direction and in which the rotation axis of the rotary blade 12 extends is defined as the left-right direction. The direction perpendicular to the up-down and left-right directions is defined as the front-rear direction, the direction from the rear handle 20 toward the front handle 18 is defined as the forward direction, and the direction from the front handle 18 toward the rear handle 20 is defined as the rearward direction. Note that, hereinafter, unless otherwise specified, the description will be made assuming that the power cutter 10 is placed on the placing surface H.

[0037] (electric motor 4) As shown in FIG. 3, the electric motor 4 includes a motor housing 42 and a motor shaft 44 that is rotatable around a rotation axis A1 relative to the motor housing 42. In this embodiment, the electric motor 4 is a brushless motor, and a stator and a rotor (not shown) are housed in the motor housing 42. A portion of the motor shaft 44 is fixed to the rotor inside the motor housing 42. A first gear 80a is fixed to the remaining portion of the motor shaft 44. In this embodiment, the first gear 80a is a bevel gear. When power is supplied to the electric motor 4, the motor shaft 44 starts to rotate around the rotation axis A1. Furthermore, the longitudinal direction of the electric motor 4 coincides with the direction in which the rotation axis A1 extends.

[0038] As shown in FIG. 2, the electric motor 4 is housed in the housing main body 14a. In this embodiment, when the power cutter 10 is viewed from the right, the rotation axis A1 of the motor shaft 44 (see FIG. 3) is disposed in a direction inclined relative to the vertical direction, from rear to front as it moves from top to bottom. In this embodiment, the inclination angle of the rotation axis A1 relative to the vertical direction is −20°. Furthermore, when the power cutter 10 is viewed from the right, the rotation axis A1 is disposed so as to be approximately perpendicular to a line Y that passes through a rotation axis A2 (see FIG. 3) of an input shaft 81 and a rotation axis A3 (see FIG. 3) of an output shaft 85, which will be described later.

[0039] As shown in FIG. 4, when the power cutter 10 is viewed from the rear, the electric motor 4 partially overlaps the rotary blade 12. The rotation axis A1 of the motor shaft 44 (see FIG. 3) of the electric motor 4 is disposed so as to be perpendicular to the left-right direction. The rotation axis A1 of the motor shaft 44 is also disposed parallel to a reference plane P, which corresponds to the plane on which the rotary blade 12 extends. The reference plane P is a plane perpendicular to the rotation axis A3 (see FIG. 3) of the output shaft 85, which will be described later. The rotation axis A1 is disposed near the reference plane P. In this embodiment, the distance from the reference plane P to the rotation axis A1 is 3.5 mm.

[0040] (Power transmission part 8) As shown in Figure 3, the power transmission unit 8 includes an input shaft 81, an output shaft 85, an input pulley 82 fixed to the input shaft 81, an output pulley 84 fixed to the output shaft 85, and a transmission belt 83 stretched between the input pulley 82 and the output pulley 84.

[0041] The input shaft 81 and the input pulley 82 are supported by the housing 14 (not shown) to be rotatable about a rotation axis A2. The rotation axis A2 of the input shaft 81 and the input pulley 82 is arranged along the left-right direction. A second gear 80b is fixed to the input shaft 81 at a position offset to the left of the input pulley 82. In this embodiment, the second gear 80b is a bevel gear. The second gear 80b meshes with the first gear 80a of the motor shaft 44. Therefore, when the motor shaft 44 rotates, the input shaft 81 also rotates simultaneously due to the meshing of the first gear 80a and the second gear 80b. At this time, the rotation speed of the input shaft 81 is reduced relative to the rotation speed of the motor shaft 44 in accordance with the gear ratio between the first gear 80a and the second gear 80b. That is, the first gear 80a and the second gear 80b not only function as a mechanism for converting the rotational motion of the motor shaft 44 about the rotational axis A1 into the rotational motion of the input shaft 81 about the rotational axis A2, but also function as a reducer. For this reason, in this specification, the first gear 80a and the second gear 80b may be collectively referred to as the "reducer 80."

[0042] As shown in FIG. 2 , the transmission belt 83 is housed in the blade arm 14b together with the input pulley 82 and the output pulley 84. In this embodiment, the input pulley 82 and the output pulley 84 are toothed pulleys, and the transmission belt 83 is a toothed belt. The input pulley 82 and the transmission belt 83 mesh with each other. The output pulley 84 and the transmission belt 83 also mesh with each other. Therefore, when the input shaft 81 rotates, the output pulley 84 also rotates simultaneously due to the input pulley 82 and the transmission belt 83 fixed to the input shaft 81. In this embodiment, the pulley diameter of the output pulley 84 is larger than the pulley diameter of the input pulley 82. Therefore, the rotational speed of the output pulley 84 is reduced relative to the rotational speed of the input pulley 82.

[0043] As shown in Fig. 3, the output pulley 84 and the output shaft 85 are supported by the housing 14 (not shown) so as to be rotatable about a rotation axis A3. The rotation axis A3 of the output pulley 84 and the output shaft 85 is disposed along the left-right direction. The rotary blade 12 is attached to the output shaft 85 at a position offset to the left of the output pulley 84. Therefore, when the output pulley 84 rotates, the rotary blade 12 also rotates simultaneously via the output shaft 85. In other words, the rotation axis A3 is an axis corresponding to the rotation axis of the rotary blade 12.

[0044] As described above, the power transmission unit 8 transmits the power from the electric motor 4 to the rotary blade 12. This allows the electric motor 4 to rotate the rotary blade 12 in the power cutter 10.

[0045] (Control board 6)

[0046] As shown in FIG. 2, the control board 6 is accommodated in the housing main body 14a. The control board 6 is disposed above the electric motor 4 in the direction in which the rotation axis A1 of the motor shaft 44 (see FIG. 3) extends. The control board 6 is disposed along a plane substantially perpendicular to the rotation axis A1 of the motor shaft 44. The control board 6 is electrically connected to the plurality of battery packs 60 and adjusts the power supplied from the plurality of battery packs 60 before supplying it to the electric motor 4. In this embodiment, since the electric motor 4 is a brushless motor, the control board 6 further includes an inverter circuit (not shown). The inverter circuit electrically connects the plurality of battery packs 60 and the electric motor 4 and converts DC power from the plurality of battery packs 60 into three-phase AC power before supplying it to the electric motor 4. The control board 6 is also electrically connected to an illuminator (not shown) provided in the housing 14 and can adjust the power supplied from the plurality of battery packs 60 before supplying it to the illuminator.

[0047] (Multiple Battery Packs 60 and Battery Interface 24) The multiple battery packs 60 each have at least one secondary battery cell (not shown). The multiple battery packs 60 are detachably attached to the battery interface 24 and can supply power to the electric motor 4. The battery interface 24 is provided in the housing main body 14a behind the electric motor 4. The battery interface 24 is also provided in the housing main body 14a so that the longitudinal directions of the right battery pack 60a (see FIG. 1) and the left battery pack 60b are attached approximately parallel to the direction in which the rotation axis A1 of the motor shaft 44 (see FIG. 3) extends. That is, in the power cutter 10, the electric motor 4 and the multiple battery packs 60 are arranged so that their respective longitudinal directions are approximately parallel.

[0048] As shown in Figure 4, when the power cutter 10 is viewed from the rear, the battery interface 24 partially overlaps the rotary blade 12. When the power cutter 10 is viewed from the rear, the right battery pack 60a and the left battery pack 60b attached to the battery interface 24 each partially overlap the electric motor 4. The right battery pack 60a and the left battery pack 60b are disposed approximately symmetrically with respect to a reference plane P, which corresponds to the plane on which the rotary blade 12 extends.

[0049] (Front handle 18 and rear handle 20) As shown in Fig. 1, the front handle 18 and the rear handle 20 are each provided on the housing main body 14a. The front handle 18 extends from above the housing main body 14a to the right and left. One end of the front handle 18 is attached near the center of the right side of the housing main body 14a, and the other end is attached to the lower part of the left side of the housing main body 14a. The rear handle 20 extends rearward from the housing main body 14a.

[0050] As shown in FIG. 2, the front handle 18 is located behind the rotary blade 12 and in front of the electric motor 4. The rear handle 20 is located behind the battery interface 24. Typically, a user holds the power cutter 10 by gripping the front handle 18 with their left hand and the rear handle 20 with their right hand. In this case, the user can adjust the attitude of the power cutter 10 by changing the position at which they grip the front handle 18.

[0051] As shown in Fig. 5, the rear handle 20 is provided with a main switch 30 that can be operated by the user with the fingers of the hand holding the rear handle 20. In this embodiment, when the user operates the main switch 30, the control board 6 (see Fig. 2) starts supplying power to the electric motor 4, and when the operation of the main switch 30 is released, the control board 6 stops supplying power to the electric motor 4. In other words, the power cutter 10 is configured to rotate the rotary blade 12 only while the main switch 30 is being operated.

[0052] The rear handle 20 is further equipped with a lock-off switch 32. The lock-off switch 32 is held on the rear handle 20 so that it can slide left and right. Although not shown, when the lock-off switch 32 is not pushed to the right relative to the rear handle 20, the main switch 30 and the lock-off switch 32 mechanically interfere with each other, prohibiting operation of the main switch 30. When the lock-off switch 32 is pushed to the right relative to the rear handle 20, the main switch 30 and the lock-off switch 32 do not mechanically interfere with each other, allowing operation of the main switch 30.

[0053] The rear handle 20 further includes an operation button 34. In this embodiment, the control board 6 (see FIG. 2) starts or stops the supply of power to an illuminator (not shown) in response to the operation of the operation button 34. In other words, the operation button 34 is a button for switching the illuminator on and off.

[0054] (Blade Cover 16) As shown in Fig. 1, the blade cover 16 is attached near the front end of the blade arm 14b and covers a portion of the rotary blade 12. The blade cover 16 prevents dust generated by the rotary blade 12 from scattering toward the user. In this embodiment, the blade cover 16 is configured to cover a portion of the rotary blade 12 in the circumferential direction (for example, an angular range of 175° or more). Furthermore, at least a portion of the blade cover 16 may be movable relative to the blade arm 14b.

[0055] (Water supply hose 50) The water supply hose 50 is provided on the right side of the power cutter 10. The tip of the water supply hose 50 is connected to the outer surface of the blade cover 16 via a plug 52. The base end of the water supply hose 50 is attached to the lower part of the rear handle 20. A water supply connector 54 is provided at the base end of the water supply hose 50. The water supply connector 54 is held by the housing main body 14a and can be connected to an external water source, such as a water faucet, via a hose (not shown). This allows the water supply hose 50 to supply water into the blade cover 16.

[0056] (Guide roller 70) As shown in FIG. 2, the guide roller 70 is attached below the housing 14. The guide roller 70 has a pair of left and right wheels 72 (see FIGS. 1 and 6). When the power cutter 10 is placed on the mounting surface H, the pair of left and right wheels 72 are arranged so as not to come into contact with the mounting surface H. A user of the power cutter 10 can stably move the rotary blade 12 forward or backward relative to the object to be cut by performing work while the pair of left and right wheels 72 are in contact with any surface (such as the mounting surface H).

[0057] (Power Cutter 10 center of gravity GT) As shown in Fig. 6, in the power cutter 10 of this embodiment configured as described above, the center of gravity GT of the power cutter 10 is located near the reference plane P, between the front handle 18 and the rear handle 20. Therefore, when a user holds the power cutter 10 by gripping the front handle 18 with his left hand and the rear handle 20 with his right hand, the posture of the power cutter 10 becomes more stable.

[0058] (Locking mechanism for the output shaft 85 and mechanism for preventing the transmission belt 83 from falling off) 7, the blade arm 14b of this embodiment is provided with a lock pin 140. The lock pin 140 is held relative to the blade arm 14b so as to be slidable in a direction substantially perpendicular to the rotation axis A3 of the output shaft 85. The lock pin 140 is biased toward the outside of the blade arm 14b by a coil spring (not shown).

[0059] The output pulley 84 of this embodiment includes a first rotating member 110 around which the transmission belt 83 is wound, and a second rotating member 120 into which the lock pin 140 is inserted. The first rotating member 110 is fixed to the output shaft 85. As will be described in detail later, the second rotating member 120 is fixed to the first rotating member 110. In other words, the first rotating member 110 and the second rotating member 120 are members that rotate around the rotation axis A3 together with the output shaft 85.

[0060] As shown in FIG. 8, the first rotating member 110 includes a first cylindrical portion 112, a flange portion 114 extending radially outward from the right end of the first cylindrical portion 112, and a first base portion 116 extending radially inward from the left end of the first cylindrical portion 112. In this embodiment, the first cylindrical portion 112 has a plurality of teeth formed at predetermined intervals in the circumferential direction, which mesh with a plurality of teeth formed on the transmission belt 83 (see FIG. 7). The transmission belt 83 is wound around the first cylindrical portion 112. The first cylindrical portion 112, the flange portion 114, and the first base portion 116 are formed seamlessly and integrally. In this embodiment, an aluminum alloy is used for the first rotating member 110.

[0061] The second rotating member 120 includes a second cylindrical portion 122 and a second base portion 124 that extends radially inward from the right end of the second cylindrical portion 122. The second cylindrical portion 122 includes a plurality of lock holes 126 that are formed at predetermined intervals in the circumferential direction. In this embodiment, the plurality of lock holes 126 are four lock holes, and are provided every quarter of the circumference of the second cylindrical portion 122 in the circumferential direction. The outer diameter of the second cylindrical portion 122 is larger than the outer diameter of the first cylindrical portion 112. The second base portion 124 is fixed to the first base portion 116 of the first rotating member 110 by screws (not shown) or the like. The second cylindrical portion 122 and the second base portion 124 are formed seamlessly and integrally. In this embodiment, the second rotating member 120 is made of iron.

[0062] As shown in Fig. 9, when the output shaft 85 is rotated to position one of the multiple lock holes 126 in the sliding direction of the lock pin 140, and the lock pin 140 is pushed in against the biasing force of the coil spring, the lock pin 140 is inserted into the lock hole 126. When the lock pin 140 is inserted into the lock hole 126, mechanical interference occurs between the lock pin 140 and the lock hole 126, prohibiting rotation of the output shaft 85 about the rotation axis A3. On the other hand, as shown in Fig. 7, when the lock pin 140 is not inserted into the lock hole 126, there is no mechanical interference between the lock pin 140 and the lock hole 126, allowing rotation of the output shaft 85 about the rotation axis A3.

[0063] When the transmission belt 83 wound around the first cylindrical portion 112 moves rightward along the direction of the rotation axis A3 of the output shaft 85, it is stopped by the flange portion 114 located to the right of the transmission belt 83. When the transmission belt 83 moves leftward along the direction of the rotation axis A3, it is stopped by the second base portion 124 located to the left of the transmission belt 83. This prevents the transmission belt 83 from falling off the output pulley 84.

[0064] (Variation) In the above embodiment, the power cutter 10 has been described as an example of the electric working machine. In another embodiment, the electric working machine may be an electric working machine other than the power cutter 10, such as an electric circular saw or a grinder.

[0065] In the above embodiment, the electric motor 4 is a brushless motor. In another embodiment, the electric motor 4 may be a motor other than a brushless motor. For example, the electric motor 4 may be a brushed motor.

[0066] In the above embodiment, the rotation axis A1 of the motor shaft 44 is inclined from rear to front relative to the vertical direction when viewed from the right side of the power cutter 10, and the inclination angle of the rotation axis A1 relative to the vertical direction is −20°. In another embodiment, the inclination angle of the rotation axis A1 relative to the vertical direction when viewed from the right side of the power cutter 10 may be an angle other than −20°. In this case, the inclination angle of the rotation axis A1 relative to the vertical direction may be changed as appropriate within the range of −45° to 45°. In yet another embodiment, the inclination angle of the rotation axis A1 relative to the vertical direction when viewed from the right side of the power cutter 10 may be outside the range of −45° to 45°.

[0067] In the above embodiment, the configuration has been described in which, when the power cutter 10 is viewed from the right, the rotation axis A1 is arranged so as to be approximately perpendicular to the line Y that passes through the rotation axis A2 of the input pulley 82 and the rotation axis A3 of the output pulley 84. In another embodiment, when the power cutter 10 is viewed from the right, the rotation axis A1 does not have to be approximately perpendicular to the line Y that passes through the rotation axis A2 and the rotation axis A3.

[0068] In the above embodiment, the first gear 80a and the second gear 80b are bevel gears. In another embodiment, the first gear 80a and the second gear 80b may be gears other than bevel gears. For example, the first gear 80a and the second gear 80b may be worm gears or the like.

[0069] In the above embodiment, the input pulley 82 and the output pulley 84 are toothed pulleys, the transmission belt 83 is a toothed belt, and a configuration has been described in which power is transmitted between the input pulley 82, the transmission belt 83, and the output pulley 84 mainly by meshing of the teeth. In another embodiment, the input pulley 82 and the output pulley 84 may be pulleys other than toothed pulleys, and the transmission belt 83 may be a belt other than a toothed belt. For example, the input pulley 82 and the output pulley 84 may be V-grooved pulleys, and the transmission belt 83 may be a flat belt or a V-belt. In this case, power is transmitted between the input pulley 82, the transmission belt 83, and the output pulley 84 mainly by friction between the members.

[0070] In the above embodiment, the pulley diameter of the output pulley 84 is larger than the pulley diameter of the input pulley 82. In another embodiment, the pulley diameter of the output pulley 84 may be the same as the pulley diameter of the input pulley 82, or may be smaller than the pulley diameter of the input pulley 82.

[0071] In the above embodiment, the electric working machine (power cutter 10) is provided with a plurality of battery packs 60, and a configuration has been described in which power is supplied from the plurality of battery packs 60 to the electric motor 4. In another embodiment, the electric working machine (power cutter 10) may be provided with a power cord that connects to an external power source instead of the plurality of battery packs 60, and power may be supplied from the external power source to the electric motor 4 via the power cord. In yet another embodiment, the electric working machine (power cutter 10) may be provided with a single battery pack instead of the plurality of battery packs 60.

[0072] In the above embodiment, the plurality of battery packs 60 is described as two battery packs (the right battery pack 60a and the left battery pack 60b). In another embodiment, the plurality of battery packs 60 may be three or more battery packs. For example, the plurality of battery packs 60 may be four battery packs.

[0073] Unlike the above-described embodiment, the power cutter 10 may further include a battery pack cover that is an openable and closable cover that covers the multiple battery packs 60. In this case, the multiple battery packs 60 can be protected from water and dust.

[0074] In the above embodiment, the configuration has been described in which the front handle 18 is disposed rearward of the rotary blade 12 and forward of the electric motor 4, and the rear handle 20 is disposed rearward of the battery interface 24. In another embodiment, the front handle 18 and the rear handle 20 may be disposed in any position as long as the front handle 18 is disposed forward of the rear handle 20.

[0075] Unlike the above-described embodiment, the power cutter 10 may further include a water tank connected to the water supply connector 54. In this case, there is no need to attach a hose or the like to connect the water supply connector 54 to an external water source, which further improves user operability. In addition, the power cutter 10 can be used even in places where water cannot be supplied from an external source, thereby improving user convenience.

[0076] In the above embodiment, a configuration has been described in which an aluminum alloy is used for the first rotating member 110 and iron is used for the second rotating member 120. In another embodiment, a material other than an aluminum alloy may be used for the first rotating member 110, and a material other than iron may be used for the second rotating member 120. For example, a resin may be used for the first rotating member 110, and an aluminum alloy may be used for the second rotating member 120.

[0077] In the above embodiment, the multiple lock holes 126 are four lock holes, and are provided at intervals of one-quarter of a circumference in the circumferential direction of the second cylindrical portion 122. In another embodiment, the four lock holes may be provided at intervals of one-quarter of a circumference or less in the circumferential direction of the second cylindrical portion 122. In yet another embodiment, the multiple lock holes 126 may be two, three, five or more lock holes.

[0078] (Correspondence) As described above, in one or more embodiments, the power cutter 10 (an example of an electric work machine) has the rotary blade 12, the output shaft 85 to which the rotary blade 12 is attached, the output pulley 84 fixed to the output shaft 85, the input shaft 81, the input pulley 82 fixed to the input shaft 81, the transmission belt 83 stretched between the input pulley 82 and the output pulley 84, the motor shaft 44, the electric motor 4 that rotates and drives the motor shaft 44, the speed reducer 80 that reduces the rotation of the motor shaft 44 and transmits it to the input shaft 81, and the housing 14 that accommodates the electric motor 4 and the speed reducer 80 and rotatably supports the input shaft 81 and the output shaft 85. The rotation axis A1 of the motor shaft 44 is arranged approximately perpendicular (an example of being inclined) to the left-right direction along the rotation axis A3 of the output shaft 85.

[0079] According to the above configuration, the longitudinal direction of the electric motor 4 is inclined with respect to the left-right direction along the rotation axis A3 of the output shaft 85. Therefore, the power cutter 10 can be made smaller in size with respect to the direction of the rotation axis A3 of the output shaft 85.

[0080] In one or more embodiments, the rotation axis A1 of the motor shaft 44 is oriented perpendicular to the left-right direction along the rotation axis A3 of the output shaft 85.

[0081] According to the above configuration, the electric motor 4 is disposed so that the longitudinal direction thereof is substantially perpendicular to the rotation axis A3 of the output shaft 85. Therefore, the power cutter 10 can be further reduced in size in the direction of the rotation axis A3 of the output shaft 85.

[0082] In one or more embodiments, when the power cutter 10 is placed on the mounting surface H, the rotation axis A3 of the output shaft 85 is arranged along the left-right direction near the front end of the housing 14, and when the power cutter 10 is viewed from the side, the rotation axis A1 of the motor shaft 44 is arranged at an inclination angle within the range of -45° to 45° relative to the up-down direction.

[0083] According to the above configuration, when the power cutter 10 is placed on the placement surface H, the power cutter 10 can be made smaller in size in the left-right direction and also in the front-rear direction.

[0084] In one or more embodiments, when the power cutter 10 is placed on the mounting surface H and viewed from the side, the rotation axis A1 of the motor shaft 44 is inclined in the vertical direction from rear to front as it moves from top to bottom.

[0085] According to the above configuration, when a user uses the power cutter 10 with the rotary blade 12 facing downward, the rotation axis A1 of the motor shaft 44 is likely to be arranged along the vertical direction. Therefore, when a user uses the power cutter 10 with the rotary blade 12 facing downward, the power cutter 10 can be made smaller in the front-to-rear direction. This improves user operability.

[0086] In one or more embodiments, when the power cutter 10 is viewed from the side, the rotation axis A1 of the motor shaft 44 is positioned approximately perpendicular to a line Y passing through the rotation axis A3 of the output shaft 85 and the rotation axis A2 of the input shaft 81.

[0087] According to the above configuration, the rotation axis A1 of the motor shaft 44 is arranged substantially perpendicular to the radial direction of the rotary blade 12 (i.e., substantially parallel to the tangential direction of the rotary blade 12). In other words, the longitudinal direction of the electric motor 4 is arranged substantially perpendicular to the radial direction of the rotary blade 12 (i.e., substantially parallel to the tangential direction of the rotary blade 12). According to the above configuration, the power cutter 10 can be made smaller in size in the radial direction of the rotary blade 12.

[0088] In one or more embodiments, the power cutter 10 further includes a front handle 18 (an example of a first handle) that is attached to the housing 14 and is held by the user's left hand (an example of one hand), and a rear handle 20 (an example of a second handle) that is attached to the housing 14 and is held by the user's right hand (an example of the other hand). When the power cutter 10 is placed on the placement surface H, the front handle 18 is located behind the rotary blade 12 and in front of the electric motor 4, and the rear handle 20 is located behind the electric motor 4.

[0089] Normally, the closer the center of gravity GT of the power cutter 10 is to the center of gravity of the user's body, the easier it is for the user to operate the power cutter. Furthermore, since the weight of the electric motor 4 is relatively large among the components of the power cutter 10, the center of gravity GT of the power cutter 10 varies significantly depending on where the electric motor 4 is located. With the above configuration, the electric motor 4 is located between the front handle 18 and the rear handle 20, so when the user uses the power cutter 10 by holding the front handle 18 and the rear handle 20, the center of gravity GT of the power cutter 10 is likely to be located close to the center of gravity of the user's body. This further improves the ease of operation for the user.

[0090] In one or more embodiments, the vehicle further includes a plurality of battery packs 60 (examples of at least one battery pack) removably attached to the housing 14 and powering the electric motor 4.

[0091] When the power cutter 10 is driven by power from an external power source, it is necessary to attach a power cord to the power cutter 10, which can lead to reduced operability. With the above configuration, there is no need to attach a power cord, which further improves user operability. In addition, it can be used even in places where an external power supply is not available, which improves user convenience.

[0092] In one or more embodiments, when the power cutter 10 is placed on the placement surface H, the plurality of battery packs 60 are disposed behind the electric motor 4 and in front of the rear handle 20.

[0093] Among the components of the power cutter 10, the weight of the multiple battery packs 60 is relatively large, so the center of gravity GT of the power cutter 10 changes significantly depending on where the multiple battery packs 60 are arranged. With the above configuration, the multiple battery packs 60 are arranged between the front handle 18 and the rear handle 20, so when a user uses the power cutter 10 by holding the front handle 18 and the rear handle 20, the center of gravity GT of the power cutter 10 is likely to be located close to the center of gravity of the user's body. This further improves user operability.

[0094] In one or more embodiments, when the power cutter 10 is placed on the placement surface H and viewed from the rear, the battery packs 60 and the electric motor 4 at least partially overlap each other.

[0095] According to the above configuration, the electric motor 4 and the plurality of battery packs 60 are arranged close to each other in the left-right and up-down directions. According to the above configuration, when the power cutter 10 is placed on the placement surface H, the power cutter 10 can be made compact in the left-right direction and also in the up-down direction.

[0096] In one or more embodiments, when the power cutter 10 is placed on the placement surface H and viewed from the rear, the rotary blade 12 and the electric motor 4 at least partially overlap each other.

[0097] According to the above configuration, the rotary blade 12 and the electric motor 4 are disposed close to each other in the left-right and up-down directions. According to the above configuration, when the power cutter 10 is placed on the placement surface H, the power cutter 10 can be made smaller in size in the left-right direction and also in the up-down direction.

[0098] In one or more embodiments, the output pulley 84 includes a first rotating member 110 and a second rotating member 120 fixed adjacent to the first rotating member 110 in the direction of the rotation axis A3 of the output shaft 85. The first rotating member 110 includes a first cylindrical portion 112 around which the transmission belt 83 is wound, and a flange portion 114 extending radially outward from the right end (an example of an end not adjacent to the second rotating member) of the first cylindrical portion 112. The second rotating member 120 includes a second cylindrical portion 122 having an outer diameter larger than that of the first cylindrical portion 112, and a second base portion 124 (an example of a base portion) extending radially inward from the right end (an example of an end adjacent to the first rotating member) of the second cylindrical portion 122. The second cylindrical portion 122 includes a plurality of locking holes 126 formed at predetermined intervals in the circumferential direction. The power cutter 10 is movably held in the housing 14 and further includes a lock pin 140 insertable into the plurality of lock holes 126 .

[0099] When a seamless, integrally formed output pulley is provided with a mechanism for preventing the transmission belt 83 from falling off and a mechanism for locking the rotation of the output shaft 85, the output pulley is formed into a complex shape. This can make it difficult to install the output pulley when assembling the power cutter 10. According to the above configuration, the output pulley 84 is composed of the first rotating member 110 and the second rotating member 120. Therefore, when assembling the power cutter 10, the first rotating member 110 and the second rotating member 120 are separately installed, which makes it easy to install the output pulley 84. Note that with the above configuration, when the transmission belt 83 wound around the first cylindrical portion 112 moves in the direction of the rotation axis A3 of the output shaft 85, it is locked by the flange portion 114 of the first rotating member 110 or the second base portion 124 of the second rotating member 120. This prevents the transmission belt 83 from falling off the first cylindrical portion 112. Furthermore, according to the above configuration, with the lock pin 140 inserted into one of the lock holes 126, if the output pulley 84 rotates relative to the housing 14, the second rotating member 120 is locked by the lock pin 140. Therefore, by inserting the lock pin 140 into one of the lock holes 126, the rotation of the output shaft 85 can be locked.

[0100] In one or more embodiments, the first cylindrical portion 112 and the flange portion 114 are formed as a single piece without any seams. The second cylindrical portion 122 and the second base portion 124 are formed as a single piece without any seams. The first rotating member 110 is made of an aluminum alloy. The second rotating member 120 is made of iron.

[0101] Because the output pulley 84 is a member that rotates together with the output shaft 85, it is desirable to use a material with a small mass for the output pulley 84. On the other hand, considering that the lock pin 140 is inserted into the output pulley 84 to lock the rotation of the output shaft 85, it is desirable to use a material with high rigidity and strength for the output pulley 84. According to the above configuration, the necessary rigidity and strength are ensured by using iron for the second rotating member 120, which is the member into which the lock pin 140 is inserted, and the weight of the output pulley 84 as a whole can be reduced by using an aluminum alloy for the first rotating member 110, which is the member around which the transmission belt 83 is wound. [Explanation of symbols]

[0102] 4: Electric motor 6: Control board 8: Power transmission section 10: Power cutter 12: Rotary blade 14: Housing 14a: Housing body 14b: Blade Arm 16: Blade cover 18: Front handle 20: Rear handle 24: Battery interface 30: Main switch 32: Lock-off switch 34: Operation button 42: Motor housing 44: Motor shaft 50: Water supply hose 52: Plug 54: Water supply connector 60: Battery pack 60a: Right battery pack 60b: Left battery pack 70: Guide roller 72 :Wheel 80: Reducer 80a: 1st gear 80b: 2nd gear 81: Input shaft 82: Input pulley 83: Transmission belt 84: Output pulley 85: Output shaft 110: First rotating member 112: First cylindrical part 114: Flange part 116: First base part 120: Second rotating member 122: Second cylindrical part 124: Second base part 126: Lock hole 140: Lock pin A1: Rotation axis A2:Rotation axis A3: Rotation axis GT: Center of gravity position H: Placement surface P: Reference plane Y: Line

Claims

1. An electric work machine, A rotating blade and an output shaft to which the rotary blade is attached; an output pulley fixed to the output shaft; An input shaft; an input pulley fixed to the input shaft; a transmission belt stretched between the input pulley and the output pulley; an electric motor having a motor shaft and rotating the motor shaft; a reducer that reduces the rotation speed of the motor shaft and transmits the reduced rotation speed to the input shaft; a housing that accommodates the electric motor and the reducer and rotatably supports the input shaft and the output shaft, The rotation axis of the motor shaft is disposed at an angle with respect to a direction along the rotation axis of the output shaft, When the electric operating machine is placed on a placement surface, The rotation axis of the output shaft is disposed along the left-right direction near the front end of the housing, When the electric working machine is viewed from the side, the rotation axis of the motor shaft is arranged at an inclination angle within a range of -45° to 45° with respect to the up-down direction.

2. The electric operating machine according to claim 1 , wherein the rotation axis of the motor shaft is disposed so as to be perpendicular to a direction along the rotation axis of the output shaft.

3. When the electric operating machine is placed on the placement surface, 2. The electric operating machine according to claim 1, wherein, when the electric operating machine is viewed from the side, the rotation axis of the motor shaft is inclined relative to the vertical direction so as to be inclined from rear to front as it goes from top to bottom.

4. 4. The electric working machine according to claim 3, wherein, when the electric working machine is viewed from the side, the rotation axis of the motor shaft is arranged so as to be approximately perpendicular to a line passing through the rotation axis of the output shaft and the rotation axis of the input shaft.

5. a first handle provided on the housing and adapted to be held by one hand of a user; a second handle provided on the housing and adapted to be held by the user's other hand; When the electric operating machine is placed on the placement surface, the first handle is disposed rearward of the rotary blade and forward of the electric motor, The electric operating machine according to claim 1 , wherein the second handle is disposed rearward of the electric motor.

6. 6. The electric work machine according to claim 5, further comprising at least one battery pack detachably attached to the housing and supplying power to the electric motor.

7. When the electric operating machine is placed on the placement surface, The electric working machine according to claim 6, wherein the at least one battery pack is disposed rearward of the electric motor and forward of the second handle.

8. When the electric operating machine is placed on the placement surface, The electric working machine according to claim 7, wherein the battery pack and the electric motor at least partially overlap each other when the electric working machine is viewed from the rear.

9. When the electric operating machine is placed on the placement surface, 9. The electric working machine according to claim 7, wherein the rotary blade and the electric motor at least partially overlap each other when the electric working machine is viewed from the rear.

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