Electric work machine

Abstract

To suppress noise generated from an electric work machine.SOLUTION: An electric work machine includes a motor including a stator including a stator core and a coil attached to the stator core, and a rotor including a rotor core and a rotor shaft fixed to the rotor core, an output portion that is placed in front of the motor and rotates by the rotational force of the motor, a first support member having a first contact surface that contacts the front end surface of the stator core, a second support member having a second contact surface that contacts the rear end surface of the stator core, and a screw connecting the first support member and the second support member such that the stator core is tightened from the front and rear directions by the first support member and the second support member.SELECTED DRAWING: Figure 8

Description

[Technical Field]

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

[0002] BACKGROUND ART In the technical field related to electric working machines, an electric working machine such as that disclosed in Patent Document 1 is known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-185652 Summary of the Invention [Problem to be solved by the invention]

[0004] Noise generated by an electric working machine may cause discomfort to the worker using the electric working machine and to people around the electric working machine.

[0005] The technology disclosed in this specification aims to suppress noise generated from an electric work machine. [Means for solving the problem]

[0006] This specification discloses an electric working machine. The electric working machine may include a motor, an output unit, a first support member, a second support member, and a screw. The motor may include a stator including a stator core and a coil attached to the stator core, and a rotor including a rotor core and a rotor shaft fixed to the rotor core. The output unit may be disposed forward of the motor and rotated by the rotational force of the motor. The first support member may have a first contact surface that contacts the front end surface of the stator core. The second support member may have a second contact surface that contacts the rear end surface of the stator core. The screw may connect the first support member and the second support member so that the stator core is fastened in the front-rear direction by the first support member and the second support member. [Effects of the Invention]

[0007] According to the technology disclosed in this specification, noise generated from an electric operating machine is suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a front perspective view showing a driver drill according to an embodiment. [Figure 2] FIG. 2 is a rear perspective view showing the driver drill according to the embodiment. [Figure 3] FIG. 3 is a side view showing the driver drill according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing a driver drill according to an embodiment. [Figure 5] FIG. 5 is an exploded perspective view from the front showing the driver drill according to the embodiment. [Figure 6] FIG. 6 is an exploded perspective view showing the driver drill according to the embodiment, as seen from the rear. [Figure 7] FIG. 7 is a cross-sectional view showing a part of the driver drill according to the embodiment. [Figure 8] FIG. 8 is a perspective view showing a part of the driver drill according to the embodiment, seen from the right rear. [Figure 9] FIG. 9 is a view of a part of the driver drill according to the embodiment as viewed from the left. [Figure 10] FIG. 10 is a view of a part of the driver drill according to the embodiment as seen from behind. [Figure 11] FIG. 11 is a view of a part of the driver drill according to the embodiment as seen from above. [Figure 12] FIG. 12 is a cross-sectional view showing a part of the driver drill according to the embodiment. [Figure 13] FIG. 13 is a cross-sectional view showing a part of the driver drill according to the embodiment. [Figure 14] FIG. 14 is an exploded perspective view from the front showing a part of the driver drill according to the embodiment. [Figure 15] FIG. 15 is an exploded perspective view from the rear showing a part of the driver drill according to the embodiment. [Figure 16] FIG. 16 is a perspective view showing the bracket member according to the embodiment, seen from behind. [Figure 17] FIG. 17 is a rear view of the bracket member according to the embodiment. [Figure 18] FIG. 18 is a front perspective view showing the support member according to the embodiment. [Figure 19] FIG. 19 is a front view of the support member according to the embodiment. [Figure 20] FIG. 20 is a cross-sectional view schematically showing a part of a driver drill according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] In one or more embodiments, the electric operating machine may include a motor, an output unit, a first support member, a second support member, and a screw. The motor may include a stator including a stator core and a coil attached to the stator core, and a rotor including a rotor core and a rotor shaft fixed to the rotor core. The output unit may be disposed forward of the motor and rotated by the rotational force of the motor. The first support member may have a first contact surface that contacts a front end surface of the stator core. The second support member may have a second contact surface that contacts a rear end surface of the stator core. The screw may connect the first support member and the second support member so that the stator core is fastened in the front-rear direction by the first support member and the second support member.

[0010] In the above configuration, noise caused by resonance of the stator core is suppressed. The stator core is fastened in the front-to-rear direction by the first support member and the second support member, thereby increasing the rigidity of the stator core. Increasing the rigidity of the stator core increases the resonant frequency of the stator core. If the resonant frequency of the stator core is low, there is a high possibility that the stator core will resonate due to rotation of the rotor. In the above configuration, the resonant frequency of the stator core is increased, thereby suppressing resonance of the stator core. Therefore, noise caused by resonance of the stator core is suppressed. Therefore, noise generated by the electric working machine is suppressed.

[0011] In one or more embodiments, the electric operating machine may include a housing made of synthetic resin having a motor housing portion that houses the motor, the first support member, the second support member, and the screw. The housing may include a left housing and a right housing fixed to the left housing.

[0012] In the above configuration, the housing has a so-called split housing structure, which improves workability when accommodating the motor, the first support member, the second support member, and the screws into the motor accommodating portion.

[0013] In one or more embodiments, the rear end of the first support member and the front end of the second support member may be spaced apart.

[0014] With the above configuration, the electric working machine can be made smaller and lighter.

[0015] In one or more embodiments, a plurality of first contact surfaces may be provided spaced apart in the circumferential direction.

[0016] With the above configuration, the electric working machine can be made smaller and lighter.

[0017] In one or more embodiments, the first support member may have a third contact surface that contacts the outer peripheral surface of the stator core.

[0018] In the above configuration, the outer peripheral surface of the stator core is supported by the first support member, thereby preventing misalignment between the central axis of the stator and the rotational axis of the rotor. The first support member supports the rotor including the rotor shaft via a bearing. The first support member also supports the stator including the stator core. That is, the first support member supports both the stator and the rotor. Therefore, misalignment between the central axis of the stator and the rotational axis of the rotor is prevented. Since misalignment between the central axis of the stator and the rotational axis of the rotor is prevented, contact between the rotor and the stator is prevented.

[0019] In one or more embodiments, a plurality of third contact surfaces may be provided spaced apart in the circumferential direction.

[0020] With the above configuration, the electric working machine can be made smaller and lighter.

[0021] In one or more embodiments, the electric working machine may include a bearing that supports a front portion of the rotor shaft. The first support member may hold the bearing.

[0022] In the above configuration, the first support member supports both the stator and the rotor. Therefore, misalignment between the central axis of the stator and the rotational axis of the rotor is suppressed. Since misalignment between the central axis of the stator and the rotational axis of the rotor is suppressed, contact between the stator and the rotor is suppressed. Furthermore, since misalignment between the central axis of the stator and the rotational axis of the rotor is suppressed, the air gap between the stator core and the rotor core can be narrowed. This is expected to result in higher motor output.

[0023] In one or more embodiments, the first support member may have a plate portion having a retaining portion that retains the bearing, and a screw boss portion that protrudes rearward from the periphery of the plate portion and into which the screw is coupled. The first contact surface may be provided on the screw boss portion.

[0024] In the above configuration, the stator core is properly fastened in the front-rear direction by the first support member and the second support member.

[0025] In one or more embodiments, a plurality of the screw boss portions may be provided at intervals in the circumferential direction, and the first contact surface may be provided on each of the plurality of screw boss portions.

[0026] With the above configuration, the electric working machine can be made smaller and lighter.

[0027] In one or more embodiments, the first support member may have a third contact surface that contacts the outer peripheral surface of the stator core. The third contact surface may be provided on the thread boss portion rearward of the first contact surface.

[0028] In the above configuration, the outer peripheral surface of the stator core is supported by the screw boss portion, which prevents the central axis of the stator from misaligning with the rotational axis of the rotor.

[0029] In one or more embodiments, a plurality of second contact surfaces may be provided spaced apart in the circumferential direction.

[0030] With the above configuration, the electric working machine can be made smaller and lighter.

[0031] In one or more embodiments, the second support member may have a fourth contact surface that contacts the outer peripheral surface of the stator core.

[0032] In the above configuration, the outer peripheral surface of the stator core is supported by the second support member, which prevents the central axis of the stator and the rotational axis of the rotor from misaligning.

[0033] In one or more embodiments, the fourth contact surface may be disposed around the outer periphery of the stator core.

[0034] In the above configuration, the outer peripheral surface of the stator core is properly supported by the second support member.

[0035] In one or more embodiments, the second support member may have a ring portion provided to surround the outer circumferential surface of the stator core and a protrusion portion protruding radially inward from the inner circumferential surface of the ring portion. The second contact surface may be provided on the protrusion portion.

[0036] In the above configuration, the stator core is properly fastened in the front-rear direction by the first support member and the second support member.

[0037] In one or more embodiments, a plurality of protrusions may be provided spaced apart in the circumferential direction, and the second contact surface may be provided on each of the plurality of protrusions.

[0038] With the above configuration, the electric working machine can be made smaller and lighter.

[0039] In one or more embodiments, the second support member may have a fourth contact surface that contacts the outer circumferential surface of the stator core. The fourth contact surface may include an inner circumferential surface of the ring portion forward of the protrusion.

[0040] In the above configuration, the outer peripheral surface of the stator core is supported by the ring portion, which prevents the central axis of the stator from misaligning with the rotational axis of the rotor.

[0041] In one or more embodiments, the screws may be arranged in four circumferentially spaced locations.

[0042] In the above configuration, the axial forces of the four screws are applied to the stator core in a well-balanced manner.

[0043] In one or more embodiments, the electric working machine may include a fan fixed to a rear portion of the rotor shaft, and the rear end of the second support member may be located forward of the fan.

[0044] In the above configuration, the second support member is not arranged around the fan, thereby suppressing the generation of noise. If the second support member were arranged around the fan, there is a possibility that so-called NZ noise would be generated. Since the second support member is not arranged around the fan, the generation of NZ noise is suppressed.

[0045] In one or more embodiments, the rear end of the screw may be located forward of the fan.

[0046] In the above configuration, since no screws are disposed around the fan, noise generation is suppressed.

[0047] In one or more embodiments, the first support member may be made of metal.

[0048] In the above configuration, deformation of the first support member is suppressed.

[0049] In one or more embodiments, the second support member may be made of metal.

[0050] In the above configuration, deformation of the second support member is suppressed.

[0051] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings, but the present disclosure is not limited thereto. The components of the embodiments described below can be combined as appropriate. In addition, some components may not be used.

[0052] In the embodiments, the positional relationship of each part will be described using the terms left, right, front, rear, top, and bottom. These terms indicate relative positions or directions based on the center of the electric operating machine.

[0053] The electric work machine has a motor. In the embodiments, a direction parallel to a rotation axis AX of the motor will be referred to as an axial direction, a direction circumferentially around the rotation axis AX will be referred to as a circumferential direction or a rotation direction, and a direction radial from the rotation axis AX will be referred to as a radial direction.

[0054] In this embodiment, the rotation axis AX extends in the front-to-rear direction. The axial direction and the front-to-rear direction coincide with each other. One axial side is the front, and the other axial side is the rear. In addition, in the radial direction, a position closer to or approaching the rotation axis AX will be referred to as the radially inner side, and a position farther from or away from the rotation axis AX will be referred to as the radially outer side.

[0055] In this embodiment, the electric work machine is a driver drill, which is a type of drilling machine or screw driving machine.

[0056] <Driver Drill Overview> FIG. 1 is a perspective view of the driver drill 1 according to the embodiment, seen from the front. FIG. 2 is a perspective view of the driver drill 1 according to the embodiment, seen from the rear. FIG. 3 is a side view of the driver drill 1 according to the embodiment. FIG. 4 is a cross-sectional view of the driver drill 1 according to the embodiment. FIG. 5 is an exploded perspective view of the driver drill 1 according to the embodiment, seen from the front. FIG. 6 is an exploded perspective view of the driver drill 1 according to the embodiment, seen from the rear. In the embodiment, the driver drill 1 is a vibration driver drill.

[0057] As shown in Figures 1, 2, 3, 4, 5, and 6, the driver drill 1 includes a housing 2, a rear cover 3, a casing 4, a battery mounting section 5, a motor 6, a power transmission mechanism 7, an output section 8, a fan 9, a trigger lever 10, a forward / reverse rotation switch lever 11, a speed switch lever 12, a mode switch ring 13, a light 14, an interface panel 15, a dial 16, a controller board 17, and a rotation sensor board 90.

[0058] The housing 2 is made of synthetic resin. In this embodiment, the housing 2 is made of nylon. The housing 2 includes a left housing 2L and a right housing 2R. The left housing 2L and the right housing 2R are fixed together with a screw 2S. The housing 2 is formed by fixing the left housing 2L and the right housing 2R together.

[0059] The housing 2 has a motor accommodating portion 21, a grip portion 22, and a battery holding portion 23.

[0060] The motor accommodating portion 21 accommodates the motor 6. The motor accommodating portion 21 is cylindrical.

[0061] The grip portion 22 is held by an operator. The grip portion 22 is disposed below the motor housing portion 21. The grip portion 22 extends downward from the motor housing portion 21. The trigger lever 10 is disposed in front of the grip portion 22.

[0062] The battery holding portion 23 houses the controller board 17. The battery holding portion 23 is disposed below the grip portion 22. The battery holding portion 23 is connected to the lower end of the grip portion 22. The external dimensions of the battery holding portion 23 are larger than the external dimensions of the grip portion 22 in both the front-rear and left-right directions.

[0063] The rear cover 3 is made of synthetic resin. In this embodiment, the rear cover 3 is made of nylon. The rear cover 3 is disposed behind the motor housing portion 21. The rear cover 3 houses the fan 9. The rear cover 3 is disposed so as to cover the opening at the rear of the motor housing portion 21. The rear cover 3 is fixed to the motor housing portion 21 with four screws 3S.

[0064] The motor accommodating section 21 has an intake port 18. The rear cover 3 has an exhaust port 19. Air from the external space of the housing 2 flows into the internal space of the housing 2 through the intake port 18. Air from the internal space of the housing 2 flows out to the external space of the housing 2 through the exhaust port 19.

[0065] The casing 4 houses the power transmission mechanism 7. The casing 4 includes a first casing 4A, a second casing 4B, a bracket member 4C, and a stop plate 4D. The second casing 4B is disposed in front of the first casing 4A. The mode switching ring 13 is disposed in front of the second casing 4B. The first casing 4A is made of synthetic resin. The second casing 4B is made of metal. In this embodiment, the second casing 4B is made of aluminum. The casing 4 is disposed in front of the motor accommodating section 21. Each of the first casing 4A and the second casing 4B is cylindrical.

[0066] The first casing 4A is fixed to the rear end of the second casing 4B. The bracket member 4C is arranged to cover the opening at the rear end of the first casing 4A. The bracket member 4C is fixed to the rear end of the first casing 4A with screws 4E. The stop plate 4D is arranged to cover the opening at the front end of the second casing 4B. The stop plate 4D is fixed to the front end of the second casing 4B with screws 4F.

[0067] The casing 4 is disposed so as to cover the front opening of the motor accommodating portion 21. The first casing 4A is disposed inside the motor accommodating portion 21. The second casing 4B is fixed to the motor accommodating portion 21 with four screws 4S.

[0068] The battery attachment section 5 is formed below the battery holding section 23. The battery attachment section 5 is connected to the battery pack 20. The battery pack 20 is attached to the battery attachment section 5. The battery pack 20 is detachable from the battery attachment section 5. The battery pack 20 includes a secondary battery. In the embodiment, the battery pack 20 includes a rechargeable lithium-ion battery. When attached to the battery attachment section 5, the battery pack 20 can supply power to the driver drill 1. The motor 6 is driven based on the power supplied from the battery pack 20. The interface panel 15 and the controller board 17 operate based on the power supplied from the battery pack 20.

[0069] The motor 6 is a power source for the driver drill 1. The motor 6 is an inner rotor type brushless motor. The motor 6 is housed in the motor housing 21. The motor 6 has a cylindrical stator 61 and a rotor 62 disposed inside the stator 61. The rotor 62 rotates relative to the stator 61. The rotor 62 includes a rotor shaft 63 extending in the axial direction (front-rear direction).

[0070] The power transmission mechanism 7 is disposed in front of the motor 6. The power transmission mechanism 7 is housed in the casing 4. The power transmission mechanism 7 connects the rotor shaft 63 and the output unit 8. The power transmission mechanism 7 transmits the power generated by the motor 6 to the output unit 8. The power transmission mechanism 7 has a plurality of gears.

[0071] The power transmission mechanism 7 includes a speed reduction mechanism 30 and a vibration mechanism 40 .

[0072] The reduction mechanism 30 reduces the rotation speed of the rotor shaft 63 and rotates the output section 8 at a lower rotational speed than the rotor shaft 63. In this embodiment, the reduction mechanism 30 has a first planetary gear mechanism 31, a second planetary gear mechanism 32, and a third planetary gear mechanism 33. At least a portion of the first planetary gear mechanism 31 is disposed forward of the motor 6. The second planetary gear mechanism 32 is disposed forward of the first planetary gear mechanism 31. The third planetary gear mechanism 33 is disposed forward of the second planetary gear mechanism 32. The first planetary gear mechanism 31 is operated by the rotational force of the motor 6. The second planetary gear mechanism 32 is operated by the rotational force of the first planetary gear mechanism 31. The third planetary gear mechanism 33 is operated by the rotational force of the second planetary gear mechanism 32.

[0073] The vibration mechanism 40 vibrates the output portion 8 in the axial direction. The vibration mechanism 40 has a first cam 41, a second cam 42, and a vibration switching ring 43.

[0074] The output unit 8 is disposed forward of the motor 6. The output unit 8 rotates due to the rotational force of the motor 6. The output unit 8 rotates with a tool bit attached based on the rotational force transmitted from the motor 6 via the power transmission mechanism 7. The output unit 8 includes a spindle 81 that rotates about a rotation axis AX based on the rotational force transmitted from the motor 6, and a chuck 82 to which the tool bit is attached. At least a portion of the spindle 81 is disposed forward of the third planetary gear mechanism 33. The spindle 81 is coupled to the third planetary gear mechanism 33. The spindle 81 rotates due to the rotational force of the motor 6 transmitted via the first planetary gear mechanism 31, the second planetary gear mechanism 32, and the third planetary gear mechanism 33. A tool bit such as a driver bit or a drill bit is detachably attached to the chuck 82.

[0075] The fan 9 is disposed behind the rotor core 62A, which will be described later. The fan 9 generates an airflow for cooling the motor 6. The fan 9 is fixed to at least a portion of the rotor 62. The fan 9 is fixed to the rear of the rotor shaft 63. The fan 9 rotates with the rotation of the rotor shaft 63. As the rotor shaft 63 rotates, the fan 9 rotates together with the rotor shaft 63. As the fan 9 rotates, air from the external space of the housing 2 flows into the internal space of the housing 2 through the air intake 18. The air that has flowed into the internal space of the housing 2 cools the motor 6 by circulating through the internal space of the housing 2. The air that has circulated through the internal space of the housing 2 flows out into the external space of the housing 2 through the air exhaust 19.

[0076] The trigger lever 10 is operated to start the motor 6. The trigger lever 10 is provided at the upper front part of the grip part 22. The front end part of the trigger lever 10 protrudes forward from the front part of the grip part 22. The trigger lever 10 is movable in the front and rear directions. The trigger lever 10 is operated by the operator. When the trigger lever 10 is operated so as to move backward, the motor 6 starts. When the operation of the trigger lever 10 is released, the motor 6 stops.

[0077] The forward / reverse switching lever 11 is operated to switch the rotation direction of the motor 6. The forward / reverse switching lever 11 is provided on the upper part of the grip portion 22. The left end of the forward / reverse switching lever 11 protrudes leftward from the left part of the grip portion 22. The right end of the forward / reverse switching lever 11 protrudes rightward from the right part of the grip portion 22. The forward / reverse switching lever 11 can move left and right. The forward / reverse switching lever 11 is operated by the operator. When the forward / reverse switching lever 11 is operated to move leftward, the motor 6 rotates in the forward direction. When the forward / reverse switching lever 11 is operated to move rightward, the motor 6 rotates in the reverse direction. When the rotation direction of the motor 6 is switched, the rotation direction of the spindle 81 is switched.

[0078] The speed switch lever 12 is operated to change the speed mode of the reduction mechanism 30. The speed switch lever 12 is provided on top of the motor housing 21. The speed switch lever 12 is movable in the front-to-rear direction relative to the motor housing 21. The speed switch lever 12 is operated by an operator. The speed modes of the reduction mechanism 30 include a high-speed mode and a low-speed mode. The high-speed mode is a speed mode in which the output unit 8 rotates at a high speed. The low-speed mode is a speed mode in which the output unit 8 rotates at a low speed. The movable range of the speed switch lever 12 is defined in the front-to-rear direction. When the speed switch lever 12 is operated to move to the high-speed mode position at the rear of the movable range, the speed mode of the reduction mechanism 30 is set to the high-speed mode. When the speed switch lever 12 is operated to move to the low-speed mode position at the front of the movable range, the speed mode of the reduction mechanism 30 is set to the low-speed mode.

[0079] The mode switching ring 13 is operated to change the operation mode of the vibration mechanism 40. The mode switching ring 13 is disposed in front of the casing 4. The mode switching ring 13 is rotatable. The mode switching ring 13 is operated by an operator. The operation modes of the vibration mechanism 40 include a vibration mode and a non-vibration mode. The vibration mode is an operation mode in which the output unit 8 is vibrated in the axial direction. The non-vibration mode is an operation mode in which the output unit 8 is not vibrated in the axial direction. When the mode switching ring 13 is operated to be positioned at the vibration mode position in the rotational direction, the operation mode of the vibration mechanism 40 is set to the vibration mode. When the mode switching ring 13 is operated to be positioned at the non-vibration mode position in the rotational direction, the operation mode of the vibration mechanism 40 is set to the non-vibration mode. The non-vibration modes include a driver mode (screw tightening mode) and a drill mode.

[0080] The light 14 emits illumination light that illuminates the area in front of the driver drill 1. The light 14 includes, for example, a light-emitting diode (LED). The light 14 is disposed below the front part of the motor housing portion 21. The light 14 is disposed above the trigger lever 10.

[0081] The interface panel 15 is provided on the upper surface of the battery holding portion 23. The interface panel 15 includes an operating device 24 and a display device 25. The interface panel 15 is plate-shaped. The operating device 24 includes operation buttons. Examples of the display device 25 include a segment display including a plurality of segment light emitters, a flat panel display such as a liquid crystal display, and an indicator-type display in which a plurality of light-emitting diodes are arranged.

[0082] A panel opening 27 is formed in the battery holding portion 23. The panel opening 27 is formed in the upper surface of the battery holding portion 23, forward of the grip portion 22. At least a portion of the interface panel 15 is disposed in the panel opening 27.

[0083] The operating device 24 is operated to change the drive mode of the motor 6. The operating device 24 is operated by an operator. The drive modes of the motor 6 include a drill mode and a clutch mode. The drill mode is a drive mode in which the motor 6 is driven regardless of the torque acting on the motor 6 when the motor 6 is driven. The clutch mode is a drive mode in which the motor 6 is stopped when the torque acting on the motor 6 exceeds a torque threshold when the motor 6 is driven.

[0084] The dial 16 is operated to change the driving conditions of the motor 6. The dial 16 is disposed in front of the battery holding portion 23. The dial 16 is rotatably supported by the battery holding portion 23. The dial 16 is rotatable 360° or more. The dial 16 is operated by an operator. The driving conditions of the motor 6 include a torque threshold. The dial 16 is operated to change the torque threshold in the clutch mode set by the operating device 24.

[0085] A dial opening is formed in the battery holding portion 23. The dial opening is formed on the right side of the front portion of the battery holding portion 23. At least a portion of the dial 16 is disposed in the dial opening .

[0086] The controller board 17 outputs a control command to control the motor 6. At least a portion of the controller board 17 is housed in the controller case 26. The controller board 17 is housed in the battery holding section 23 while being held in the controller case 26. The controller board 17 includes a circuit board on which a plurality of electronic components are mounted. Examples of electronic components mounted on the circuit board include a processor such as a CPU (Central Processing Unit), a non-volatile memory such as a ROM (Read Only Memory) or storage, a volatile memory such as a RAM (Random Access Memory), a transistor, a capacitor, and a resistor.

[0087] The controller board 17 sets the drive conditions of the motor 6 based on the operation of the dial 16. As described above, the drive conditions of the motor 6 include a torque threshold. In the clutch mode, the controller board 17 sets the torque threshold based on the operation of the dial 16.

[0088] Furthermore, in the clutch mode, the controller board 17 stops the motor 6 when the torque acting on the motor 6 during driving of the motor 6 exceeds a set torque threshold.

[0089] Furthermore, the controller board 17 causes the display device 25 to display the set driving conditions of the motor 6. The controller board 17 causes the display device 25 to display the set torque threshold value.

[0090] The rotation sensor board 90 includes a circuit board on which a plurality of rotation sensors are mounted to detect the rotation of the rotor 62. The controller board 17 supplies a drive current to the motor 6 based on the detection data of the rotation sensors.

[0091] <Motor and power transmission mechanism> Fig. 7 is a cross-sectional view showing a portion of the driver drill 1 according to the embodiment. As shown in Fig. 7, the motor 6 has a cylindrical stator 61 and a rotor 62 disposed inside the stator 61. The rotor 62 includes a rotor shaft 63 extending in the axial direction.

[0092] The stator 61 includes a stator core 61A including a plurality of stacked steel plates, a front insulator 61B disposed in front of the stator core 61A, a rear insulator 61C disposed in the rear of the stator core 61A, a plurality of coils 61D wound around the stator core 61A via the front insulator 61B and the rear insulator 61C, and a busbar unit 61G fixed to the front insulator 61B. The busbar unit 61G includes a short-circuit member 61E and a resin member 61F that covers at least a portion of the short-circuit member 61E.

[0093] The rotor 62 rotates about a rotation axis AX. The rotor 62 has a rotor shaft 63, a rotor core 62A arranged around the rotor shaft 63, and a plurality of permanent magnets 62B held by the rotor core 62A. The rotor core 62A is cylindrical. The rotor core 62A includes a plurality of laminated steel plates. The rotor core 62A has through holes extending in the axial direction. A plurality of through holes are formed in the circumferential direction. The permanent magnets 62B are arranged in each of the plurality of through holes of the rotor core 62A.

[0094] The rotation sensor board 90 includes a circuit board on which multiple rotation sensors that detect the rotation of the rotor 62 are mounted. The rotation sensor board 90 is attached to the front insulator 61B. The rotation sensors mounted on the rotation sensor board 90 include magnetic sensors that detect the magnetic field of the permanent magnet 62B. An example of the magnetic sensor is a Hall sensor that includes a Hall element. The rotation sensor detects the rotation of the rotor 62 by detecting the magnetic field of the permanent magnet 62B. The controller board 17 supplies a drive current to the coil 61D based on the detection data of the rotation sensors.

[0095] The rotor shaft 63 rotates around a rotation axis AX. The rotation axis AX of the rotor shaft 63 coincides with the rotation axis of the output section 8. A front portion of the rotor shaft 63 is rotatably supported by a bearing 64. A rear portion of the rotor shaft 63 is rotatably supported by a bearing 65. The bearing 64 is held by a bracket member 4C arranged in front of the stator 61. The bearing 65 is held by the rear cover 3. The front end portion of the rotor shaft 63 is arranged forward of the bearing 64. The front end portion of the rotor shaft 63 is arranged in the internal space of the casing 4.

[0096] A pinion gear 31S is provided at the front end of the rotor shaft 63. The pinion gear 31S functions as a sun gear of the first planetary gear mechanism 31. The pinion gear 31S is rotated by the motor 6. The rotor shaft 63 is connected to the first planetary gear mechanism 31 of the reduction mechanism 30 via the pinion gear 31S.

[0097] The first planetary gear mechanism 31 has a plurality of planetary gears 31P arranged around a pinion gear 31S, a first carrier 31C that supports the plurality of planetary gears 31P, and an internal gear 31R that is arranged around the plurality of planetary gears 31P. The first carrier 31C rotatably supports the planetary gears 31P via pins 31A. A gear is provided on the outer periphery of the first carrier 31C.

[0098] The second planetary gear mechanism 32 has a sun gear 32S, a plurality of planetary gears 32P arranged around the sun gear 32S, a second carrier 32C that supports the plurality of planetary gears 32P, and an internal gear 32R that is arranged around the plurality of planetary gears 32P. The second carrier 32C rotatably supports the planetary gears 32P via pins 32A. The sun gear 32S is arranged in front of the first carrier 31C. The diameter of the sun gear 32S is smaller than the diameter of the first carrier 31C. The first carrier 31C and the sun gear 32S are integral. The first carrier 31C and the sun gear 32S rotate together.

[0099] The third planetary gear mechanism 33 has a sun gear 33S, a plurality of planetary gears 33P arranged around the sun gear 33S, a third carrier 33C that supports the plurality of planetary gears 33P, and an internal gear 33R that is arranged around the plurality of planetary gears 33P. The third carrier 33C rotatably supports the planetary gears 33P via pins 33A. The sun gear 33S is arranged in front of the second carrier 32C.

[0100] The speed reduction mechanism 30 also has a speed change ring 34 connected to the speed change lever 12, and a connecting ring 35 located in front of the speed change ring 34. The connecting ring 35 is fixed to the inner surface of the first casing 4A. A gear is provided on the inner periphery of the connecting ring 35. Coil springs 39 are located in front and behind the upper part of the speed change ring 34. The speed change ring 34 is connected to the speed change lever 12 via the coil springs 39.

[0101] The speed switch ring 34 switches between low-speed mode and high-speed mode. The speed switch ring 34 is connected to the internal gear 32R. The speed switch lever 12 is connected to the internal gear 32R via the speed switch ring 34. The speed switch lever 12, the speed switch ring 34, and the internal gear 32R can move together. When the speed switch lever 12 is operated by an operator, the speed switch ring 34 moves back and forth inside the first casing 4A. With the internal gear 32R and the planetary gear 32P meshed, the speed switch ring 34 moves back and forth between a low-speed mode position and a high-speed mode position rearward of the low-speed mode position, thereby switching between the low-speed mode and the high-speed mode. When the speed switch lever 12 is operated, the low-speed mode and the high-speed mode are switched.

[0102] When the internal gear 32R is positioned in the low speed mode position, it comes into contact with the coupling ring 35. The contact of the internal gear 32R with the coupling ring 35 restricts the rotation of the internal gear 32R. When the internal gear 32R is positioned in the high speed mode position, it moves away from the coupling ring 35. The movement of the internal gear 32R away from the coupling ring 35 allows the rotation of the internal gear 32R.

[0103] Furthermore, when the internal gear 32R is positioned at the low speed mode position, it meshes with the planetary gear 32P. When the internal gear 32R is positioned at the high speed mode position, it meshes with both the planetary gear 32P and the first carrier 31C.

[0104] When the internal gear 32R is disposed in the low-speed mode position, and the rotor shaft 63 is rotated by the driving of the motor 6, the pinion gear 31S rotates, and the planetary gear 31P revolves around the pinion gear 31S. The revolution of the planetary gear 31P causes the first carrier 31C and the sun gear 32S to rotate at a rotational speed lower than the rotational speed of the rotor shaft 63. When the sun gear 32S rotates, the planetary gear 32P revolves around the sun gear 32S. The revolution of the planetary gear 32P causes the second carrier 32C and the sun gear 33S to rotate at a rotational speed lower than the rotational speed of the first carrier 31C. In this way, when the internal gear 32R is positioned in the low-speed mode position and the motor 6 is driven, both the deceleration function of the first planetary gear mechanism 31 and the deceleration function of the second planetary gear mechanism 32 are exerted, and the second carrier 32C and the sun gear 33S rotate in low-speed mode.

[0105] When the internal gear 32R is positioned in the high-speed mode position, and the rotor shaft 63 is rotated by the drive of the motor 6, the pinion gear 31S rotates, and the planetary gear 31P revolves around the pinion gear 31S. The revolution of the planetary gear 31P causes the first carrier 31C and the sun gear 32S to rotate at a rotational speed lower than the rotational speed of the rotor shaft 63. When the internal gear 32R is positioned in the high-speed mode position, the internal gear 32R meshes with both the planetary gear 32P and the first carrier 31C, and therefore the internal gear 32R and the first carrier 31C rotate together. The rotation of the internal gear 32R causes the planetary gear 32P to revolve at the same revolution speed as the rotational speed of the internal gear 32R. Due to the revolution of planetary gear 32P, second carrier 32C and sun gear 33S rotate at the same rotational speed as first carrier 31C. In this way, when motor 6 is driven with internal gear 32R positioned in the high-speed mode position, the speed reduction function of first planetary gear mechanism 31 is exerted but the speed reduction function of second planetary gear mechanism 32 is not exerted, and second carrier 32C and sun gear 33S rotate in high-speed mode.

[0106] When second carrier 32C and sun gear 33S rotate, planetary gear 33P revolves around sun gear 33S. The revolution of planetary gear 33P rotates third carrier 33C.

[0107] The spindle 81 is connected to the third carrier 33C via a spindle lock mechanism 50. The spindle lock mechanism 50 has a lock cam 51 arranged around the spindle 81 and a lock ring 52 that rotatably supports the lock cam 51. The lock ring 52 is arranged inside the second casing 4B. The lock ring 52 is fixed to the second casing 4B. Rotation of the third carrier 33C rotates the spindle 81.

[0108] The spindle 81 is rotatably supported by a bearing 83 and a bearing 84. While being supported by the bearings 83 and 84, the spindle 81 is movable in the front-rear direction.

[0109] The spindle 81 has a flange portion 81F. A coil spring 87 is disposed between the flange portion 81F and the bearing 83. The flange portion 81F contacts the front end portion of the coil spring 87. The coil spring 87 generates an elastic force that moves the spindle 81 forward.

[0110] The chuck 82 is capable of holding a tool bit. The chuck 82 is connected to the front part of the spindle 81. A screw hole 81R is provided in the front end part of the spindle 81. When the spindle 81 rotates, the chuck 82 rotates. The chuck 82 rotates while holding the tool bit.

[0111] The first cam 41 and the second cam 42 of the vibration mechanism 40 are disposed inside the second casing 4B. In the front-rear direction, the first cam 41 and the second cam 42 are disposed between the bearing 83 and the bearing 84.

[0112] The first cam 41 is ring-shaped. The first cam 41 is arranged around the spindle 81. The first cam 41 is fixed to the spindle 81. The first cam 41 rotates together with the spindle 81. Cam teeth are provided on the rear surface of the first cam 41. The first cam 41 is supported by a stop ring 44. The stop ring 44 is arranged around the spindle 81. In the front-rear direction, the stop ring 44 is arranged between the first cam 41 and the bearing 83.

[0113] The second cam 42 is ring-shaped. The second cam 42 is disposed behind the first cam 41. The second cam 42 is disposed around the spindle 81. The second cam 42 is rotatable relative to the spindle 81. Cam teeth are provided on the front surface of the second cam 42. The cam teeth on the front surface of the second cam 42 mesh with the cam teeth on the rear surface of the first cam 41. A pawl is provided on the rear surface of the second cam 42.

[0114] A support ring 45 is disposed between the second cam 42 and the bearing 84 in the front-rear direction. The support ring 45 is disposed inside the second casing 4B. The support ring 45 is fixed to the second casing 4B. A plurality of steel balls 46 are disposed on the front surface of the support ring 45. A washer 47 is disposed between the steel balls 46 and the second cam 42. The second cam 42 is rotatable in the space defined by the support ring 45 and the washer 47 while its front-rear movement is restricted.

[0115] The vibration switching ring 43 switches between vibration mode and non-vibration mode. The mode switching ring 13 is connected to the vibration switching ring 43 via a cam ring 48. The mode switching ring 13 and the cam ring 48 are rotatable together. The vibration switching ring 43 is movable in the front-rear direction. The vibration switching ring 43 has a protrusion 43T. The protrusion 43T is inserted into a guide hole provided in the second casing 4B. The vibration switching ring 43 is movable in the front-rear direction while being guided by the guide hole provided in the second casing 4B. The protrusion 43T restricts the rotation of the vibration switching ring 43. When the mode switching ring 13 is operated by an operator, the vibration switching ring 43 moves in the front-rear direction. The vibration switching ring 43 switches between vibration mode and non-vibration mode by moving in the front-rear direction between a forward position and a retracted position further rearward than the forward position. By operating the mode switching ring 13, the vibration mode and the non-vibration mode can be switched.

[0116] The vibration mode includes a state in which rotation of the second cam 42 is restricted. The non-vibration mode includes a state in which rotation of the second cam 42 is permitted. When the vibration switching ring 43 moves to the forward position, rotation of the second cam 42 is restricted. When the vibration switching ring 43 moves to the backward position, rotation of the second cam 42 is permitted.

[0117] In the vibration mode, at least a portion of the vibration switching ring 43 that has moved to the forward position comes into contact with the second cam 42. The contact between the vibration switching ring 43 and the second cam 42 restricts the rotation of the second cam 42. When the motor 6 is driven while the rotation of the second cam 42 is restricted, the first cam 41 fixed to the spindle 81 rotates while contacting the cam teeth of the second cam 42. As a result, the spindle 81 rotates while vibrating in the front-to-rear direction.

[0118] In the non-vibration mode, the vibration switching ring 43, which has moved to the retracted position, moves away from the second cam 42. The movement of the vibration switching ring 43 away from the second cam 42 allows the second cam 42 to rotate. When the motor 6 is driven while the rotation of the second cam 42 is allowed, the second cam 42 rotates together with the first cam 41 and the spindle 81. This allows the spindle 81 to rotate in the front-to-rear direction without vibrating.

[0119] The vibration switching ring 43 is disposed around the first cam 41 and the second cam 42. The vibration switching ring 43 also has a facing portion 43S that faces the rear surface of the second cam 42. The facing portion 43S protrudes radially inward from the rear portion of the vibration switching ring 43.

[0120] When the mode switching ring 13 is operated and the vibration switching ring 43 moves to the forward position, the claw on the rear surface of the second cam 42 comes into contact with the opposing portion 43S of the vibration switching ring 43. This restricts the rotation of the second cam 42. In this way, when the mode switching ring 13 is operated and the vibration switching ring 43 moves to the forward position, the vibration mechanism 40 is switched to the vibration mode.

[0121] When the mode switching ring 13 is operated and the vibration switching ring 43 moves to the retracted position, the opposing portion 43S of the vibration switching ring 43 moves away from the second cam 42. This allows the second cam 42 to rotate. In this way, when the mode switching ring 13 is operated and the vibration switching ring 43 moves to the retracted position, the vibration mechanism 40 is switched to the non-vibration mode.

[0122] <Noise suppression structure> FIG. 8 is a perspective view of a portion of the driver drill 1 according to the embodiment, seen from the rear. FIG. 9 is a view of a portion of the driver drill 1 according to the embodiment, seen from the right rear. FIG. 10 is a view of a portion of the driver drill 1 according to the embodiment, seen from the rear. FIG. 11 is a view of a portion of the driver drill 1 according to the embodiment, seen from above. FIG. 12 is a cross-sectional view of a portion of the driver drill 1 according to the embodiment. FIG. 13 is a cross-sectional view of a portion of the driver drill 1 according to the embodiment. FIG. 14 is an exploded perspective view of a portion of the driver drill 1 according to the embodiment, seen from the front. FIG. 15 is an exploded perspective view of a portion of the driver drill 1 according to the embodiment, seen from the rear.

[0123] As shown in Figures 5 and 6, in this embodiment, the housing 2 includes a left housing 2L and a right housing 2R fixed to the left housing 2L with screws 2S. That is, the housing 2 has a so-called split housing structure. Each of Figures 8 to 15 shows the internal structure of the motor accommodating portion 21. Figure 12 corresponds to a cross-sectional view taken along line AA in Figure 9. Figure 13 corresponds to a cross-sectional view taken along line BB in Figure 9.

[0124] As shown in FIGS. 7 to 15, the motor 6 has a stator 61 and a rotor 62 that rotates relative to the stator 61.

[0125] The stator 61 includes a stator core 61A, a front insulator 61B, a rear insulator 61C, a coil 61D, and a busbar unit 61G.

[0126] The stator core 61A is cylindrical. The stator core 61A is disposed so as to surround the rotation axis AX. The stator core 61A has a front end face 601, a rear end face 602, and an outer circumferential surface 603. The front end face 601 faces forward. The rear end face 602 faces rearward. The front end face 601 and the rear end face 602 are each annular. The outer circumferential surface 603 is disposed so as to connect the periphery of the front end face 601 and the periphery of the rear end face 602. The outer circumferential surface 603 is disposed so as to surround the rotation axis AX.

[0127] The front insulator 61B is disposed in front of the stator core 61A. A part of the front end surface 601 of the stator core 61A is covered by the front insulator 61B. A part of the front end surface 601 of the stator core 61A is exposed.

[0128] The rear insulator 61C is disposed at a portion of the stator core 61A. A portion of the rear end surface 602 of the stator core 61A is covered by the rear insulator 61C. A portion of the rear end surface 602 of the stator core 61A is exposed.

[0129] The coil 61D is attached to the stator core 61A via the front insulator 61B and the rear insulator 61C. In the embodiment, six coils 61D are provided.

[0130] The bus bar unit 61G includes a short-circuit member 61E and a resin member 61F that covers at least a portion of the short-circuit member 61E. The short-circuit member 61E is connected to the controller board 17 via lead wires. The short-circuit member 61E connects a plurality of coils 61D via fusing terminals 61H. A pair of coils 61D is connected via wires 61J. The fusing terminals 61H are connected to the wires 61J.

[0131] The rotor 62 includes a rotor shaft 63, a rotor core 62A, and a permanent magnet 62B.

[0132] The rotor core 62A is cylindrical. The rotor core 62A is disposed around the rotor shaft 63. The rotor shaft 63 is fixed to the rotor core 62A. The permanent magnets 62B are held by the rotor core 62A. In this embodiment, four permanent magnets 62B are provided.

[0133] The front portion of the rotor shaft 63 is supported by a bearing 64. The rear portion of the rotor shaft 63 is supported by a bearing 65. The bearing 64 is a ball bearing. The bearing 65 is also a ball bearing. The fan 9 is fixed to the rear portion of the rotor shaft 63. The fan 9 is a centrifugal fan.

[0134] In the embodiment, the driver drill 1 includes a bracket member 4C which is a first support member that supports the front portion of the stator core 61A, a support member 70 which is a second support member that supports the rear portion of the stator core 61A, and a screw 60S which connects the bracket member 4C and the support member 70.

[0135] The bracket member 4C is made of a metal, such as iron, aluminum, or magnesium.

[0136] The support member 70 is made of metal. Examples of metals that form the support member 70 include iron, aluminum, and magnesium.

[0137] Fig. 16 is a perspective view of a bracket member 4C according to an embodiment, seen from the rear. Fig. 17 is a view of a bracket member 4C according to an embodiment, seen from the rear. Fig. 18 is a perspective view of a support member 70 according to an embodiment, seen from the front. Fig. 19 is a view of a support member 70 according to an embodiment, seen from the front.

[0138] The bracket member 4C holds the bearing 64. At least a portion of the bracket member 4C contacts the front end surface 601 of the stator core 61A. The bracket member 4C has a plate portion 101, a screw boss portion 102, and a screw boss portion 104.

[0139] The plate portion 101 has an opening 103. The opening 103 is provided in the center of the plate portion 101. The plate portion 101 has a retaining portion 108 that retains the bearing 64. The retaining portion 108 includes a first retaining surface 108A that contacts the outer ring of the bearing 64, and a second retaining surface 108B that contacts at least a portion of the front end surface of the bearing 64. The second retaining surface 108B is annular. The second retaining surface 108B is arranged around the opening 103.

[0140] In this embodiment, a notch 105 is provided in the upper part of the plate part 101. At least a part of the upper part of the speed change ring 34 is disposed inside the notch 105.

[0141] As shown in FIG. 15 , a peripheral wall 106 is provided on the front surface of the plate portion 101. The peripheral wall 106 is provided so as to surround the opening 103. The internal gear 31R is arranged inside the peripheral wall 106. A recess 107 is provided in a part of the peripheral wall 106. A protrusion 31T is provided on the outer circumferential surface of the internal gear 31R. The protrusion 31T is arranged in the recess 107. By placing the protrusion 31T in the recess 107, relative rotation between the internal gear 31R and the bracket member 4C is suppressed.

[0142] The screw boss portion 102 protrudes rearward from the peripheral edge of the plate portion 101. The screw 60S is coupled to the screw boss portion 102. The screw boss portion 102 has a screw hole 102H into which the threaded portion of the screw 60S is inserted.

[0143] A plurality of screw boss portions 102 are provided at intervals in the circumferential direction. In this embodiment, four screw boss portions 102 are provided at intervals in the circumferential direction.

[0144] The screw boss portion 104 is provided on the peripheral edge portion of the plate portion 101. The screw boss portion 104 has an opening 104H in which the middle portion of the screw 4E is disposed.

[0145] A plurality of screw bosses 104 are provided at intervals in the circumferential direction. In this embodiment, four screw bosses 104 are provided at intervals in the circumferential direction.

[0146] Bracket member 4C has contact surface 112, which is a first contact surface that contacts front end surface 601 of stator core 61A, and contact surface 111, which is a third contact surface that contacts outer circumferential surface 603 of stator core 61A.

[0147] The contact surface 112 faces rearward. The contact surface 112 contacts the front end surface 601 of the stator core 61A. A plurality of contact surfaces 112 are provided at intervals in the circumferential direction. In the embodiment, four contact surfaces 112 are provided at intervals in the circumferential direction.

[0148] The contact surface 111 faces radially inward. The contact surface 111 contacts the front portion of the outer circumferential surface 603 of the stator core 61A. A plurality of contact surfaces 111 are provided at intervals in the circumferential direction. In this embodiment, four contact surfaces 111 are provided at intervals in the circumferential direction.

[0149] The contact surface 112 and the contact surface 111 are each provided on the screw boss portion 102. The contact surface 112 is provided on each of the plurality of screw boss portions 102. The contact surface 111 is provided on each of the plurality of screw boss portions 102. The contact surface 111 is provided on the screw boss portion 102 rearward of the contact surface 112.

[0150] In the embodiment, the thread boss portion 102 includes a first portion 102A and a second portion 102B that is disposed radially inward from the first portion 102A. The rear end portion of the first portion 102A is disposed rearward from the rear end portion of the second portion 102B. The contact surface 112 includes a rear end surface of the second portion 102B. The contact surface 112 is disposed rearward from the second portion 102B and includes an inner surface of the first portion 102A that faces radially inward.

[0151] As described above, a portion of the front end face 601 of the stator core 61A is covered by the front insulator 61B. A portion of the front end face 601 of the stator core 61A is exposed. There are at least four exposed portions of the front end face 601. Each of the four contact surfaces 112 contacts an exposed portion of the front end face 601.

[0152] At least a portion of the support member 70 contacts the rear end surface 602 of the stator core 61 A. The support member 70 has a ring portion 71, a screw boss portion 72, and a protrusion portion 74.

[0153] The ring portion 71 has a first ring portion 71A and a second ring portion 71B. The first ring portion 71A is positioned rearward of the second ring portion 71B. The inner diameter of the first ring portion 71A is smaller than the inner diameter of the second ring portion 71B. An opening 73 is provided at the rear end of the first ring portion 71A.

[0154] The screw boss portion 72 is provided on the outer peripheral surface of the ring portion 71. The screw boss portion 72 has an opening 72H in which the middle portion of the screw 60S is disposed.

[0155] A plurality of screw boss portions 72 are provided at intervals in the circumferential direction. In this embodiment, four screw boss portions 72 are provided at intervals in the circumferential direction.

[0156] The protrusions 74 protrude radially inward from the inner circumferential surface of the ring portion 71. A plurality of the protrusions 74 are provided at intervals in the circumferential direction. In the embodiment, four protrusions 74 are provided at intervals in the circumferential direction. The front end of each of the protrusions 74 is located rearward of the front end of the ring portion 71 (second ring portion 71B).

[0157] Support member 70 has contact surface 75 as a second contact surface that contacts rear end surface 602 of stator core 61A, and contact surface 76 as a fourth contact surface that contacts outer circumferential surface 603 of stator core 61A.

[0158] The contact surface 75 faces forward. The contact surface 75 contacts the rear end surface 602 of the stator core 61A. A plurality of contact surfaces 75 are provided at intervals in the circumferential direction. In the embodiment, four contact surfaces 75 are provided at intervals in the circumferential direction.

[0159] The contact surface 76 faces radially inward. The contact surface 76 comes into contact with a rear portion of the outer circumferential surface 603 of the stator core 61A. The contact surface 76 is provided so as to surround the outer circumferential surface 603 of the stator core 61A.

[0160] The contact surface 75 is provided on each of the plurality of protruding portions 74. The contact surface 76 is provided on the ring portion 71. The contact surface 76 includes an inner circumferential surface of the second ring portion 71B on the front side of the protruding portions 74.

[0161] As described above, a portion of the rear end surface 602 of the stator core 61A is covered by the rear insulator 61C. A portion of the rear end surface 602 of the stator core 61A is exposed. There are at least four exposed portions of the rear end surface 602. Each of the four contact surfaces 75 contacts an exposed portion of the rear end surface 602.

[0162] The screws 60S connect the bracket member 4C and the support member 70 together so that the stator core 61A is fastened by the bracket member 4C and the support member 70 in the front-rear direction.

[0163] In the embodiment, four screws 60S are arranged at intervals in the circumferential direction. The screws 60S are inserted into the openings 72H of the support member 70 from the rear of the support member 70. With the middle portions of the screws 60S positioned in the openings 72H, the threaded portions of the screws 60S are inserted into the threaded holes 102H of the bracket member 4C. The screws 60S are fixed to the bracket member 4C via the support member 70, thereby fixing the bracket member 4C and the support member 70 to the stator core 61A.

[0164] By tightening the four screws 60S into the screw holes 102H, the distance between the bracket member 4C and the support member 70 in the front-rear direction is shortened. The screws 60S are pulled in the axial direction (front-rear direction), generating an axial force. This fixes the bracket member 4C and the support member 70 to the stator core 61A. The axial force of the screws 60S tightens the stator core 61A in the front-rear direction by the bracket member 4C and the support member 70. In other words, the stator core 61A is subjected to compressive stress from the bracket member 4C and the support member 70 so as to be compressed in the front-rear direction.

[0165] When the screws 60S are fastened to the screw holes 102H and the bracket member 4C and the support member 70 are fixed to the stator core 61A, the rear insulator 61C and the busbar unit 61G are disposed inside the first ring portion 71A. The front end of the rotor shaft 63 is disposed inside the casing 4 through the opening 103 of the bracket member 4C.

[0166] 9 and 11, when the screws 60S are fastened to the screw holes 102H and the bracket member 4C and the support member 70 are fixed to the stator core 61A, the rear end of the support member 70 is positioned forward of the fan 9. The rear end of the screws 60S is also positioned forward of the fan 9.

[0167] When the screws 60S are fastened to the screw holes 102H and the bracket member 4C and the support member 70 are fixed to the stator core 61A, the rear end of the bracket member 4C is spaced apart from the front end of the support member 70. The rear end of the bracket member 4C includes the rear end of the screw boss portion 102 (first portion 102A). The front end of the support member 70 includes the front end of the ring portion 71 (second ring portion 71B).

[0168] <Effects> As described above, in the embodiment, the driver drill 1, which is an electric power tool, includes the motor 6, the output unit 8, the bracket member 4C serving as a first support member, the support member 70 serving as a second support member, and the screw 60S. The motor 6 includes the stator 61 including the stator core 61A and the coil 61D attached to the stator core 61A, and the rotor 62 including the rotor core 62A and the rotor shaft 63 fixed to the rotor core 62A. The output unit 8 is disposed forward of the motor 6 and rotates by the torque of the motor 6. The bracket member 4C has a contact surface 112 serving as a first contact surface that contacts the front end surface 601 of the stator core 61A. The support member 70 has a contact surface 75 serving as a second contact surface that contacts the rear end surface 602 of the stator core 61A. The screw 60S connects the bracket member 4C and the support member 70 so that the stator core 61A is fastened in the front-rear direction by the bracket member 4C and the support member 70.

[0169] In the above configuration, noise caused by resonance of the stator core 61A is suppressed. The rigidity of the stator core 61A is increased by fastening the stator core 61A in the front-rear direction by the bracket member 4C and the support member 70. Increasing the rigidity of the stator core 61A increases the resonant frequency of the stator core 61A. If the resonant frequency of the stator core 61A is low, there is a high possibility that the stator core 61A will resonate due to the rotation of the rotor 62. In the above configuration, the resonant frequency of the stator core 61A is increased, thereby suppressing resonance of the stator core 61A. Therefore, noise caused by resonance of the stator core 61A is suppressed. Therefore, noise generated by the driver drill 1 is suppressed.

[0170] In this embodiment, the driver drill 1 includes a housing 2 made of synthetic resin having a motor housing portion 21 that houses the motor 6, the bracket member 4C, the support member 70, and the screw 60S. The housing 2 includes a left housing 2L and a right housing 2R fixed to the left housing 2L.

[0171] In the above configuration, the housing 2 has a so-called half-housing structure, which makes it easy to accommodate the motor 6, bracket member 4C, support member 70, and screw 60S in the motor accommodating portion 21.

[0172] In this embodiment, the rear end of the bracket member 4C and the front end of the support member 70 are spaced apart.

[0173] With the above configuration, the driver drill 1 can be made smaller and lighter in weight.

[0174] In this embodiment, a plurality of contact surfaces 112 are provided at intervals in the circumferential direction.

[0175] With the above configuration, the driver drill 1 can be made smaller and lighter in weight.

[0176] In the embodiment, the bracket member 4C has a contact surface 111, which is a third contact surface, that comes into contact with the outer circumferential surface 603 of the stator core 61A.

[0177] In the above configuration, the outer peripheral surface 603 of the stator core 61A is supported by the bracket member 4C, thereby preventing misalignment between the central axis of the stator 61 and the rotational axis of the rotor 62. The bracket member 4C supports the rotor 62 including the rotor shaft 63 via the bearing 64. The bracket member 4C also supports the stator 61 including the stator core 61A. That is, the bracket member 4C supports both the stator 61 and the rotor 62. Therefore, misalignment between the central axis of the stator 61 and the rotational axis of the rotor 62 is prevented. Since the central axis of the stator 61 and the rotational axis of the rotor 62 are prevented from misaligning, contact between the stator 61 and the rotor 62 is prevented.

[0178] In this embodiment, a plurality of contact surfaces 111 are provided at intervals in the circumferential direction.

[0179] With the above configuration, the driver drill 1 can be made smaller and lighter in weight.

[0180] In this embodiment, the driver drill 1 includes a bearing 64 that supports the front portion of the rotor shaft 63. The bracket member 4C holds the bearing 64.

[0181] In the above configuration, the bracket member 4C supports both the stator 61 and the rotor 62. Therefore, misalignment between the central axis of the stator 61 and the rotational axis of the rotor 62 is suppressed. Since misalignment between the central axis of the stator 61 and the rotational axis of the rotor 62 is suppressed, contact between the stator 61 and the rotor 62 is suppressed. Furthermore, since misalignment between the central axis of the stator 61 and the rotational axis of the rotor 62 is suppressed, the air gap between the stator core 61A and the rotor core 62A can be narrowed. This is expected to result in higher output from the motor 6.

[0182] In this embodiment, the bracket member 4C has a plate portion 101 having a retaining portion 108 that retains the bearing 64, and a screw boss portion 102 that protrudes rearward from the periphery of the plate portion 101 and to which the screw 60S is coupled. A contact surface 112 is provided on the screw boss portion 102.

[0183] In the above configuration, the stator core 61A is properly fastened by the bracket member 4C and the support member 70 in the front-rear direction.

[0184] In this embodiment, a plurality of screw boss portions 102 are provided at intervals in the circumferential direction. The contact surface 112 is provided on each of the plurality of screw boss portions 102.

[0185] With the above configuration, the driver drill 1 can be made smaller and lighter in weight.

[0186] In the embodiment, the bracket member 4C has a contact surface 111 that comes into contact with the outer peripheral surface 603 of the stator core 61A. The contact surface 111 is provided on the rear side of the contact surface 112 in the screw boss portion .

[0187] In the above configuration, outer peripheral surface 603 of stator core 61A is supported by screw boss portion 102, so that misalignment between the central axis of stator 61 and the rotation axis of rotor 62 is suppressed.

[0188] In this embodiment, a plurality of contact surfaces 75 are provided at intervals in the circumferential direction.

[0189] With the above configuration, the driver drill 1 can be made smaller and lighter in weight.

[0190] In the embodiment, the support member 70 has a contact surface 76, which is a fourth contact surface, that contacts the outer circumferential surface 603 of the stator core 61A.

[0191] In the above configuration, outer peripheral surface 603 of stator core 61A is supported by support member 70, so that misalignment between the central axis of stator 61 and the rotation axis of rotor 62 is suppressed.

[0192] In the embodiment, the contact surface 76 is provided to surround the outer circumferential surface 603 of the stator core 61A.

[0193] In the above configuration, outer peripheral surface 603 of stator core 61A is properly supported by support member .

[0194] In the embodiment, the support member 70 has a ring portion 71 provided to surround the outer peripheral surface 603 of the stator core 61A, and a protruding portion 74 protruding radially inward from the inner peripheral surface of the ring portion 71. The contact surface 75 is provided on the protruding portion 74.

[0195] In the above configuration, the stator core 61A is properly fastened by the bracket member 4C and the support member 70 in the front-rear direction.

[0196] In this embodiment, a plurality of protrusions 74 are provided at intervals in the circumferential direction. The contact surface 75 is provided on each of the plurality of protrusions 74.

[0197] With the above configuration, the driver drill 1 can be made smaller and lighter in weight.

[0198] In the embodiment, the support member 70 has a contact surface 76 that contacts the outer peripheral surface 603 of the stator core 61A. The contact surface 76 includes the inner peripheral surface of the ring portion 71 (second ring portion 71B) on the front side of the protrusion 74.

[0199] In the above configuration, outer peripheral surface 603 of stator core 61A is supported by ring portion 71 (second ring portion 71B), so that the central axis of stator 61 and the rotation axis of rotor 62 are prevented from misaligning.

[0200] In this embodiment, four screws 60S are arranged at intervals in the circumferential direction.

[0201] In the above configuration, the axial forces of the four screws 60S are applied to the stator core 61A in a well-balanced manner.

[0202] In this embodiment, the driver drill 1 includes a fan 9 fixed to the rear portion of the rotor shaft 63. The rear end of the support member 70 is disposed forward of the fan 9.

[0203] In the above configuration, the support member 70 is not arranged around the fan 9, thereby suppressing the generation of noise. If the support member 70 were arranged around the fan 9, which is a centrifugal fan, there is a possibility that so-called NZ noise would be generated. Since the support member 70 is not arranged around the fan 9, the generation of NZ noise is suppressed.

[0204] In this embodiment, the rear end of the screw 60S is located in front of the fan 9.

[0205] In the above configuration, the screws 60S are not arranged around the fan 9, which is a centrifugal fan, so that noise generation is suppressed.

[0206] In this embodiment, the bracket member 4C is made of metal.

[0207] The above configuration suppresses deformation of the bracket member 4C. If the bracket member 4C is made of, for example, synthetic resin, there is a possibility that the bracket member 4C will deform due to changes in the environment (humidity or temperature) in which the driver drill 1 is used. That is, a bracket member 4C made of synthetic resin may deform due to moisture absorption or heat. If the bracket member 4C deforms, there is a possibility that the central axis of the stator 61 and the rotation axis of the rotor 62 may become misaligned. The above configuration suppresses deformation of the bracket member 4C, thereby suppressing misalignment between the central axis of the stator 61 and the rotation axis of the rotor 62.

[0208] In an embodiment, the support member 70 is made of metal.

[0209] With the above configuration, even if the environment (humidity or temperature) in which the driver drill 1 is used changes, deformation of the support member 70 is suppressed.

[0210] <Other embodiments> FIG. 20 is a cross-sectional view schematically illustrating a portion of a driver drill 1 according to another embodiment. In the above-described embodiment, the bracket member 4C and the support member 70 sandwich the stator core 61A from the front-rear direction, and the bracket member 4C holds the bearing 64. As shown in FIG. 20, the bracket member 4C does not have to hold the bearing 64. In the example shown in FIG. 20, the bearing 64 is held by a bearing holding member 4G separate from the bracket member 4C. By sandwiching the stator core 61A from the front-rear direction between the bracket member 4C and the support member 70, noise caused by resonance of the stator core 61A is suppressed. Furthermore, by not holding the bearing 64, the bracket member 4C need not be large, thereby reducing the weight of the driver drill.

[0211] In the above-described embodiment, the electric work machine is a driver drill (percussion driver drill), which is a type of power tool. The power tool is not limited to a driver drill. Examples of the power tool include an impact driver, an angle drill, a screwdriver, a hammer, a hammer drill, a circular saw, and a reciprocating saw.

[0212] In the above-described embodiment, the electric work machine may be a gardening tool (outdoor power equipment). Examples of gardening tools include a chainsaw, a brush cutter, a lawn mower, a hedge trimmer, and a blower. [Explanation of symbols]

[0213] 1...Driver drill, 2...Housing, 2L...Left housing, 2R...Right housing, 2S...Screw, 3...Rear cover, 3S...Screw, 4...Casing, 4A...First casing, 4B...Second casing, 4C...Bracket member (first support member), 4D...Stop plate, 4E...Screw, 4F...Screw, 4S...Screw, 5...Battery mounting section, 6...Motor, 7...Power transmission mechanism, 8...Output section, 9...Fan, 10...Trigger lever, 11...Forward / reverse switch lever, 12...Speed ​​switch lever, 13...Mode switch ring, 14...Light, 15...Interface panel, 16...Dial, 17 ...controller board, 18...intake port, 19...exhaust port, 20...battery pack, 21...motor housing, 22...grip portion, 23...battery holding portion, 24...operation device, 25...display device, 26...controller case, 27...panel opening, 28...dial opening, 30...reduction mechanism, 31...first planetary gear mechanism, 31A...pin, 31C...first carrier, 31P...planetary gear, 31R...internal gear, 31T...projection portion, 31S...pinion gear, 32...second planetary gear mechanism, 32A...pin, 32C...second carrier, 32P...planetary gear, 32R...internal gear gear, 32S...sun gear, 33...third planetary gear mechanism, 33A...pin, 33C...third carrier, 33P...planetary gear, 33R...internal gear, 33S...sun gear, 34...speed change ring, 35...connecting ring, 39...coil spring, 40...vibration mechanism, 41...first cam, 42...second cam, 43...vibration change ring, 43S...opposing portion, 43T...projection portion, 44...stop ring, 45...support ring, 46...steel ball, 47...washer, 48...cam ring, 50...spindle lock mechanism, 51...lock cam, 52...lock ring, 60S...screw, 6 1... stator, 61A... stator core, 61B... front insulator, 61C... rear insulator, 61D... coil, 61E... short-circuit member, 61F... resin member, 61G... busbar unit, 61H... fusing terminal, 61J... wire, 62... rotor, 62A... rotor core, 62B... permanent magnet, 63... rotor shaft, 64... bearing, 65... bearing, 70... support member (second support member), 71... ring portion, 71A... first ring portion, 71B... second ring portion, 72... screw boss portion, 72H... opening, 73... opening, 74... protrusion, 75... contact surface (second contact surface),76...contact surface (fourth contact surface) 81...spindle, 81F...flange portion, 81R...screw hole, 82...chuck, 83...bearing, 84...bearing, 87...coil spring, 90...rotation sensor board, 101...plate portion, 102...screw boss portion, 102A...first portion, 102B...second portion, 102H...screw hole, 103...opening, 104...screw boss portion, 104H...opening, 105...notch, 106...peripheral wall portion, 107...recess, 108...retaining portion, 108A...first retaining surface, 108B...second retaining surface, 111...contact surface (third contact surface), 112...contact surface (first contact surface), 601...front end surface, 602...rear end surface, 603...outer circumferential surface, AX...rotating axis.

Claims

1. a motor including a stator including a stator core and a coil attached to the stator core, and a rotor including a rotor core and a rotor shaft fixed to the rotor core; an output section disposed forward of the motor and rotated by a rotational force of the motor; a first support member having a first contact surface that contacts a front end surface of the stator core; a second support member having a second contact surface that contacts the rear end surface of the stator core; a screw connecting the first support member and the second support member so that the stator core is fastened by the first support member and the second support member in a front-rear direction, the first support member has a plate portion and a screw boss portion that protrudes rearward from the plate portion and to which the screw is coupled, The first contact surface is provided on the screw boss portion. Electric work equipment.

2. a housing made of synthetic resin having a motor accommodating portion that accommodates the motor, the first support member, the second support member, and the screw, The housing includes a left housing and a right housing fixed to the left housing. The electric operating machine according to claim 1 .

3. The rear end of the first support member and the front end of the second support member are spaced apart. The electric operating machine according to claim 1 or 2.

4. The first contact surface is provided in plurality at intervals in the circumferential direction. The electric operating machine according to any one of claims 1 to 3.

5. The first support member has a third contact surface that contacts an outer peripheral surface of the stator core. The electric operating machine according to any one of claims 1 to 4.

6. The third contact surface is provided in plurality at intervals in the circumferential direction. The electric operating machine according to claim 5.

7. a bearing supporting a front portion of the rotor shaft; The first support member holds the bearing. The electric operating machine according to claim 1 .

8. the plate portion has a holding portion that holds the bearing, The screw boss portion protrudes rearward from the peripheral edge portion of the plate portion. The electric operating machine according to claim 7.

9. The screw boss portion is provided in plurality at intervals in the circumferential direction, The first contact surface is provided on each of the plurality of screw boss portions. The electric operating machine according to claim 8.

10. the first support member has a third contact surface that contacts an outer peripheral surface of the stator core, The third contact surface is provided rearward of the first contact surface in the screw boss portion. The electric operating machine according to claim 8 or 9.

11. The second contact surface is provided in plurality at intervals in the circumferential direction. The electric operating machine according to any one of claims 1 to 10.

12. The second support member has a fourth contact surface that contacts an outer peripheral surface of the stator core. The electric operating machine according to any one of claims 1 to 11.

13. The fourth contact surface is provided to surround an outer peripheral surface of the stator core. The electric operating machine according to claim 12.

14. the second support member has a ring portion provided to surround an outer circumferential surface of the stator core, and a protrusion portion protruding radially inward from an inner circumferential surface of the ring portion, The second contact surface is provided on the protrusion. The electric operating machine according to any one of claims 1 to 10.

15. The protruding portions are provided in a plurality at intervals in the circumferential direction, The second contact surface is provided on each of the plurality of protrusions. The electric operating machine according to claim 14.

16. the second support member has a fourth contact surface that contacts an outer peripheral surface of the stator core, the fourth contact surface includes an inner circumferential surface of the ring portion forward of the protrusion, The electric operating machine according to claim 14 or 15.

17. The screws are arranged four at intervals in the circumferential direction. The electric operating machine according to any one of claims 1 to 16.

18. a fan fixed to a rear portion of the rotor shaft; A rear end portion of the second support member is disposed forward of the fan. The electric operating machine according to any one of claims 1 to 17.

19. The rear end of the screw is located forward of the fan. The electric operating machine according to claim 18.

20. The first support member is made of metal. The electric operating machine according to any one of claims 1 to 19.

21. The second support member is made of metal. The electric operating machine according to any one of claims 1 to 20.

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