Electric rotary tools

Abstract

The present invention provides an electric rotary tool capable of improving the rigidity of a housing for holding a stator. The vibrating screwdriver drill (1) comprises: a brushless motor (5) having a stator (50) and a rotor (51) rotatable relative to the stator (50); a first gearbox (70) disposed in front of the brushless motor (5); a planetary gear (82) disposed inside the first gearbox (70), the rotation of the rotor (51) being transmitted to the planetary gear (82); a main shaft (9) protruding forward from the first gearbox (70), the rotation of which is transmitted from the planetary gear (82) to the main shaft (9); a cylindrical housing (11) having an integral cylindrical shape, which accommodates the brushless motor (5), is open at the front and closed at the rear; a split housing (12) divided into two parts on the left and right, which is connected to the front of the cylindrical housing (11) and holds the first gearbox (70); and a handle (3) extending downward from the split housing (12).

Description

Technical Field

[0001] The present invention relates to electric rotating tools such as screwdriver drills. Background Art

[0002] Electric rotary tools are known to have the following structure: a motor is positioned at the rear of a main body extending in the front-to-back direction, and an output unit is positioned in front of the motor. For example, in Patent Document 1, a motor is positioned at the rear of a main body extending in the front-to-back direction, and a gear assembly comprising a speed reduction unit and an output unit is positioned in front of the motor. The output unit includes a vibration mechanism and a spindle protruding forward.

[0003] The housing of the main body includes a split housing formed by assembling left and right half-split housings with screws, and a lid-shaped rear cover screwed from the rear of the split housings.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-131357 Summary of the Invention

[0007] In the conventional housing structure described above, the main body is formed from three components. The stator is held by the left and right split housings, making it difficult to ensure the rigidity of the split housings. Furthermore, the stator and rotor are held by separate components, making coaxial arrangement difficult.

[0008] Therefore, an object of the present invention is to provide an electric rotary tool capable of increasing the rigidity of a housing that grips a stator.

[0009] Furthermore, another object of the present invention is to provide an electric rotary tool that can easily achieve coaxial arrangement of a stator and a rotor.

[0010] In order to achieve the above-mentioned purpose, the first invention in the present invention relates to an electric rotary tool, characterized in that the electric rotary tool comprises: a motor having a stator and a rotor capable of rotating relative to the stator; a gear box, which is arranged in front of the motor; a gear, which is arranged inside the gear box and to which the rotation of the rotor is transmitted; an output shaft, which protrudes forward from the gear box and to which the rotation is transmitted from the gear; an integral cylindrical shell, which accommodates the motor, is open at the front and closed at the rear; a gear box shell divided into two parts on the left and right, which is connected to the front of the cylindrical shell and holds the gear box; and a holding shell, which extends downward from the gear box shell.

[0011] In order to achieve the above-mentioned purpose, the second invention of the present invention relates to an electric rotary tool, characterized in that the electric rotary tool comprises: a housing, which constitutes an outer contour and has a first integral cylindrical housing, left and right split housings arranged on the front side of the first integral cylindrical housing, and a second integral cylindrical housing arranged on the front side of the left and right split housings; a motor, which is accommodated in the first integral cylindrical housing; a switch and a controller, which are accommodated in the left and right split housings; a power transmission part, which is accommodated in the second integral cylindrical housing and is driven by the motor ; and a front-end tool holding portion, which is arranged on the front side of the second integral cylindrical shell and rotates with the help of the power transmission portion, the motor comprising: a stator, the outer periphery of which is directly held by the first integral cylindrical shell; and a rotor, which is arranged on the inner periphery of the stator, and the rear part of the rotor shaft of the rotor is directly held by the first integral cylindrical shell with the help of a bearing, the electric rotary tool has a plurality of screws extending in the front-to-back direction, and the plurality of screws are used to fix the first integral cylindrical shell, the left and right split shells and the second integral cylindrical shell.

[0012] According to the present invention, the rigidity of the cylindrical housing that holds the stator can be increased. In addition, as another effect, the coaxial arrangement of the stator and the rotor can be easily achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a three-dimensional diagram of a vibrating screwdriver drill.

[0014] Figure 2 It is the front view of the vibrating screwdriver drill.

[0015] Figure 3 It is the rear view of the vibrating screwdriver drill.

[0016] Figure 4 is a side view of a vibrating screwdriver drill.

[0017] Figure 5 yes Figure 2 A-A line cross-sectional view.

[0018] Figure 6 This is an exploded perspective view of the main body viewed from the front and upper side.

[0019] Figure 7 This is an exploded perspective view of the main body viewed from the rear and lower side.

[0020] Figure 8 It is the front view of the cylindrical shell.

[0021] Figure 9 yes Figure 5 An enlarged view of the main part of the .

[0022] Figure 10 yes Figure 2 Enlarged cross-sectional view of line B-B.

[0023] Figure 11 yes Figure 9 Enlarged cross-sectional view of line C-C.

[0024] Figure 12 yes Figure 9 Enlarged cross-sectional view of line D-D.

[0025] Figure 13 yes Figure 9 Enlarged cross-sectional view of line E-E.

[0026] Figure 14 yes Figure 10 Enlarged cross-sectional view of line F-F.

[0027] Figure 15 This is an explanatory diagram showing a state where the brushless motor is inserted into the cylindrical housing.

[0028] Description of Reference Numerals

[0029] 1…Oscillating screwdriver drill; 2…Main body; 3…Handle; 5…Brushless motor; 6…Gear assembly; 7…Reduction unit; 8…Output unit; 9…Spindle; 10…Drill chuck; 11…Cylindrical housing; 12…Split housing; 15…Upper screw boss; 17…Lower screw boss; 18…Frame; 21…Support rib; 23…Positioning rib; 24…Guide protrusion; 25…Front inclined surface; 26…Rear inclined surface; 27…Air inlet; 28…Exhaust hole; 30…Intermediate cylinder; 35…Matching portion; 50…Stator; 51…Rotor; 56…Anti-rotation plate; 57…Left support portion; 58…Locking recess; 59…Right support portion; 64…Rotating shaft; 65…Bearing; 66…Bearing retaining portion; 67…Fan; 68…Screw fastening portion; 69…Screw; 70…First gear box; 71…Second gear box; 72…Mode switching ring. DETAILED DESCRIPTION

[0030] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0031] (Instructions for vibrating screwdriver drill)

[0032] Figure 1 This is a perspective view showing a vibration screwdriver drill as an example of an electric rotary tool. Figure 2 is the main view, Figure 3 It is the rear view. Figure 4 It is a side view. Figure 5 yes Figure 2 A-A line cross-sectional view.

[0033] The vibrating screwdriver drill 1 includes a main body 2 and a handle 3. The main body 2 extends in the front-to-back direction. The handle 3 protrudes from the lower side of the main body 2. The main body 2 and the handle 3 form a T-shape when viewed from the side. A battery mounting portion 4 is formed at the lower end of the handle 3.

[0034] The main body 2 is equipped with a brushless motor 5 and a gear assembly 6. The brushless motor 5 is located at the rear of the main body 2, and the gear assembly 6 is located in front of the brushless motor 5. The gear assembly 6 includes a speed reduction unit 7 and an output unit 8 located in front of the speed reduction unit 7. The output unit 8 includes a spindle 9 protruding forward. A drill chuck 10 is attached to the front end of the spindle 9. The drill chuck 10 can hold a drill bit (not shown).

[0035] The housing of the vibration screwdriver drill 1 includes a cylindrical housing 11 and a split housing 12 .

[0036] The cylindrical housing 11 is arranged at the rear of the main body 2 and houses the brushless motor 5. The cylindrical housing 11 is formed into a bottomed cylindrical shape with an open front and a closed rear. Figure 6 and Figure 7 As shown, the cylindrical housing 11 includes a cylindrical portion 11a, a plate-shaped portion 11b, and an opening 11c. The cylindrical portion 11a extends in the front-to-back direction. The plate-shaped portion 11b is connected to the rear end of the cylindrical portion 11a and closes the cylindrical portion 11a. The opening 11c opens the front of the cylindrical portion 11a. An expanded diameter portion 13 is formed at the front end of the cylindrical portion 11a. The inner diameter of the expanded diameter portion 13 is larger than the inner diameter of the rear end of the cylindrical portion 11a.

[0037] A protrusion 14 is formed on the upper front side of the cylindrical housing 11. Protrusion 14 protrudes upward from the outer circumference of the cylindrical portion 11a and extends in the horizontal direction. Two upper screw bosses 15, 15 are formed on the left and right ends of protrusion 14, facing forward. A transverse rib 16 protrudes between upper screw bosses 15, 15 and at the rear end of protrusion 14. Transverse rib 16 extends in the horizontal direction and protrudes upward from upper screw bosses 15, 15.

[0038] Two lower screw bosses 17, 17, extending forward and to the left and right are formed on the front lower side of the cylindrical housing 11. A frame portion 18 is formed between lower screw bosses 17, 17. Frame portion 18 is formed in a U-shape when viewed from below, with the front and bottom open. Frame portion 18 is continuously formed with extensions 19 extending inward from the left and right side edges and rear edge. A protrusion 20 is formed on the rear lower surface of frame portion 18.

[0039] Also like Figure 8 and Figure 9 As shown, a plurality of support ribs 21, 21, ... are formed on the inner peripheral surface of the cylindrical housing 11 including the expanded diameter portion 13. Each support rib 21 is formed parallel to the axial direction of the cylindrical housing 11. Each support rib 21 is formed at predetermined intervals in the circumferential direction.

[0040] A reduced diameter portion 22 is formed along the entire circumference of the rear inner circumference of the cylindrical housing 11. The inner diameter of the reduced diameter portion 22 is smaller than the inner diameter of the front side. The reduced diameter portion 22 is located radially outward of the inner surface of the support rib 21 in the radial direction of the cylindrical housing 11.

[0041] A plurality of positioning ribs 23, 23, ... are formed on the inner circumference of the reduced diameter portion 22, on the upper, lower, left, and right sides. Each positioning rib 23 is formed parallel to the axis of the cylindrical housing 11. The end surface of the positioning rib 23 on the radially inner side of the cylindrical housing 11 is located closer to the axis of the cylindrical housing 11 than the end surface of the support rib 21 on the radially inner side.

[0042] Three guide protrusions 24, 24, ... are provided protruding radially inward from the reduced diameter portion 22. Each guide protrusion 24 has a front inclined surface 25 and a rear inclined surface 26. The front inclined surface 25 protrudes toward the axis side of the cylindrical shell 11 as it approaches the rear. The rear inclined surface 26 protrudes toward the axis side of the cylindrical shell 11 as it approaches the front. Each guide protrusion 24 is formed into a triangular shape when viewed from the side, protruding toward the axis side of the cylindrical shell 11 with the maximum amplitude between the front inclined surface 25 and the rear inclined surface 26. The upper and right guide protrusions 24, 24 of the three guide protrusions 24 are provided to protrude from the positioning rib 23. The guide protrusion 24 on the lower left side is provided to protrude from the inner circumferential surface of the reduced diameter portion 22. The apex of each guide protrusion 24 is located on a concentric circle C ( Figure 8 ) on. The concentric circle C is slightly larger than the outer diameter of the fan 67 described later.

[0043] A plurality of air inlet holes 27, 27, ... are formed on the left and right sides of the front portion of the cylindrical housing 11. Each air inlet hole 27 is in the shape of a slit. Figure 12 As shown, it is disposed between the support ribs 21, 21. A plurality of exhaust holes 28, 28, ... are formed in the reduced diameter portion 22 of the cylindrical housing 11. Each exhaust hole 28 is formed in a slit shape extending in the circumferential direction of the cylindrical housing 11.

[0044] The split housing 12 is connected to an intermediate cylinder 30 located in front of the cylindrical housing 11 and the handle 3. The split housing 12 has left and right half-split housings 12a and 12b. The half-split housings 12a and 12b are fixed to the handle 3 from the right side using multiple screws 31, 31, etc.

[0045] Four cylindrical portions 32, 32, ... are formed on the outer periphery of the intermediate cylinder 30. Each cylindrical portion 32 is coaxially located in front of the upper and lower screw bosses 15, 17 of the cylindrical housing 11 and extends in the front-to-back direction. A window 33 is formed between the upper and left cylindrical portions 32, 32 to expose the speed switching rod 85 described later. A hole 14a ( Figure 6 ).

[0046] A plurality of circumferentially extending ribs 34 are formed at predetermined intervals at the rear end of the intermediate tube 30. The ribs 34 fit inside the enlarged diameter portion 13 of the cylindrical housing 11. The support ribs 21 are disposed between the ribs 34.

[0047] A fitting portion 35 is formed at the rear end of the upper portion of the handle 3. Fitting portion 35 is formed by aligning the half-width portions 35a and 35b of the left and right half-split housings 12a and 12b, respectively. Fitting portion 35 extends rearward and fits into frame portion 18 of cylindrical housing 11. A locking portion 36 is formed on the outer periphery of fitting portion 35, which engages with extension portion 19 from above. A pair of left and right clamping protrusions 37, 37 are provided below fitting portion 35, projecting rearward. Clamping protrusions 37, 37 are located on the left and right sides, sandwiching protrusion 20 of extension portion 19.

[0048] Therefore, if the fitting portion 35 of the handle 3 is fitted into the frame portion 18 from the front, Figure 12 As shown in FIG. 1 , the locking portion 36 is locked to the upper side of the extension portion 19. At the same time, the clamping protrusions 37, 37 are arranged on the left and right sides of the protrusion 20 ( Figure 3 、 Figure 13 The frame portion 18 and the fitting portion 35 fit together to position the cylindrical housing 11 and the split housing 12 relative to each other in the left-right direction.

[0049] A switch 40 ( Figure 5 A trigger 41 is connected to the front side of the switch 40. A forward / reverse switch button 42 is provided above the switch 40 to switch the rotation direction of the brushless motor 5. A pair of left and right lights 43, 43 are provided in front of the forward / reverse switch button 42. The lights 43, 43 illuminate the front of the drill chuck 10.

[0050] The battery pack 44 is slidably mounted on the battery mounting portion 4 from the front. A terminal block 45 is provided at the bottom of the battery mounting portion 4. The battery pack 44 is electrically connected to the terminal block 45. A controller 46 is housed within the battery mounting portion 4, above the terminal block 45. The controller 46 includes a control circuit board 47. The control circuit board 47 houses a microcomputer, switching elements, and other components for controlling the brushless motor 5.

[0051] Also like Figure 9 and Figure 10 As shown, the brushless motor 5 is an inner rotor type motor having a stator 50 and a rotor 51 arranged inside the stator 50. The stator 50 has a stator core 52, front and rear insulators 53A and 53B, and a plurality of coils 54, 54, etc. The stator core 52 is formed by stacking a plurality of laminated steel plates. The insulators 53A and 53B are provided on the front and rear sides of the stator core 52. Each coil 54 is wound around the stator core 52 with the aid of the insulators 53A and 53B. A plurality of connection terminals 55a are provided on the front insulator 53A. Each connection terminal 55a is adjacent to the opening 11c of the cylindrical housing 11 and fuses the wires led out from the coils 54. A wiring component 55 is connected to each connection terminal 55a. The connection terminals 55a and the wiring components 55 form a three-phase connection.

[0052] Also like Figure 11 As shown, a detent 56 is formed at the lower portion of the front insulator 53A, at the center in the horizontal direction. The detent 56 is formed in a strip shape extending horizontally and protrudes downward from the stator core 52. A left support portion 57 is formed to the right of the half-split housing 12a, which forms the left side of the intermediate cylinder 30. The left support portion 57 has a locking recess 58 in which the detent 56 is locked. A right support portion 59 is formed in the half-split housing 12b, which forms the right side of the intermediate cylinder 30. The right support portion 59 abuts against the right side of the left support portion 57, thereby closing the right side of the locking recess 58.

[0053] A sensor circuit board 60 is mounted between the front insulator 53A and the terminal block 55. A rotation detection element is mounted on the sensor circuit board 60. The rotation detection element can detect the magnetic field of a permanent magnet 63, described later. The sensor circuit board 60 is adjacent to the opening 11c of the cylindrical housing 11.

[0054] The terminal block 55 and the sensor circuit board 60 are arranged on the front side of the stator 50. Therefore, even if the cylindrical housing 11 is formed into a single cylindrical shape, the three-phase power line 55b connected to the terminal block 55 and the signal line 60a connected to the sensor circuit board 60 can be easily routed from the opening 11c of the cylindrical housing 11 to the controller 46 in the handle 3. This also shortens the power line 55b and the signal line 60a.

[0055] Also like Figure 6 、 7 and Figure 13 As shown, four notches 61 , 61 , . . . are formed on the upper, lower, left, and right sides of the rear insulating member 53B. Each notch 61 is formed at a position corresponding to the front of the positioning rib 23 of the cylindrical housing 11 .

[0056] The rotor 51 has a rotor core 62 and a plurality of permanent magnets 63, 63, .... A rotating shaft 64 is fixed to the axis of the rotor core 62. The permanent magnets 63, 63, ... are embedded in the through-holes of the rotor core 62. The rear end of the rotating shaft 64 is supported by a bearing 65. The bearing 65 is retained by a bearing retaining portion 66 protruding from the inner bottom surface of the rear portion of the cylindrical housing 11. A fan 67 is fixed between the bearing 65 and the rotor core 62 and to the rotating shaft 64. The exhaust hole 28 is located radially outside the fan 67. The center of the rear surface of the fan 67 is recessed toward the front side, thereby allowing the bearing retaining portion 66 to protrude. Therefore, the bearing 65 and the bearing retaining portion 66 overlap with the fan 67 in the radial direction of the cylindrical housing 11.

[0057] The gear assembly 6 and the split housing 12 are pre-assembled on the brushless motor 5. Figure 11 Thus, the anti-rotation piece 56 of the front insulator 53A is positioned downward relative to the split housing 12 and engages with the locking recess 58 of the left support portion 57 of the intermediate cylinder 30. Thus, the stator 50 is held by the intermediate cylinder 30 while being anti-rotated by the insulator 53A.

[0058] Then, the brushless motor 5 is assembled into the cylindrical housing 11. At this time, the bearing 65 is first inserted from the opening 11c of the cylindrical housing 11, and then the rotor 51 is inserted from the opening 11c of the cylindrical housing 11. Furthermore, the bearing 65 is engaged with the bearing holding portion 66 from the front. Then, the fan 67, which is retreating in the cylindrical housing 11 together with the bearing 65, passes through the reduced diameter portion 22. Figure 15 As shown by the double-dotted line in the middle, its outer periphery abuts against any one of the three guide protrusions 24. Therefore, the fan 67 is not affected by the magnetic force of the rotor 51 and is guided toward the center side along the front inclined surface 25 of the guide protrusion 24 as shown by the solid line. Therefore, the fan 67 and the bearing 65 retreat in a state where the axis is consistent with the axis of the cylindrical shell 11. Through this centering, the bearing 65 is smoothly engaged with the bearing retaining portion 66. If the bearing 65 is engaged, the fan 67 is located behind the guide protrusion 24 and close to the plate-shaped portion 11b. Since the rear inclined surface 26 is formed behind the guide protrusion 24, a gap between the fan 67 and the fan 67 can be ensured.

[0059] Then, the stator 50 is inserted from the opening 11c of the cylindrical housing 11. Figure 9 、 10 and Figure 13 As shown, the positioning ribs 23 abut against the upper, lower, left, and right rear end surfaces of the stator core 52, which are exposed through the notches 61 of the insulating member 53B. Consequently, the stator 50 is restricted from rearward movement and is coaxially held within the cylindrical housing 11 by the support ribs 21. Since the support ribs 21 are located within the notches 61, their circumferential position is also determined to a certain extent.

[0060] Then, if Figure 14 As shown, the support ribs 21 of the cylindrical housing 11 are positioned between the wall ribs 34, 34, thereby engaging the wall ribs 34 of the intermediate cylinder 30 with the expanded diameter portion 13 of the cylindrical housing 11. Simultaneously, the engaging portion 35 is engaged from the front with the frame portion 18 on the lower surface of the cylindrical housing 11. The cylindrical housing 11 is then assembled to the split housing 12 in a rotationally restricted state. At this time, the pinion gear 80 meshes with the planetary gears 82.

[0061] The gear assembly 6 includes four screw fastening portions 68 , 68 , ... at the rear end of a large diameter cylindrical portion 73 of a second gear case 71 described later. Each screw fastening portion 68 is located in front of each cylindrical portion 32 provided on the outer periphery of the intermediate cylinder 30 .

[0062] Therefore, the screws 69, 69, ... that penetrate the screw fastening parts 68 are passed through the cylinder parts 32 of the intermediate cylinder 30 from the front. Furthermore, the screws 69 are screwed into the upper and lower screw bosses 15, 17 provided on the cylindrical housing 11. Figures 1 to 4 As shown, the cylindrical housing 11 , the split housing 12 and the gear assembly 6 are integrally connected by screws 69 .

[0063] The gear assembly 6 includes a cylindrical first gear case 70, a cylindrical second gear case 71, and a mode switching ring 72. The second gear case 71 is assembled to the front side of the first gear case 70. The mode switching ring 72 is assembled to the front side of the second gear case 71. The mode switching ring 72 and the first gear case 70 are made of resin. The second gear case 71 is made of aluminum. Figure 9 and Figure 10 As shown, the second gear case 71 has a double cylindrical shape, which includes a large diameter cylindrical portion 73 located on the outside and a small diameter cylindrical portion 74 located on the inside and extending further forward than the large diameter cylindrical portion 73 on a concentric circle. The large diameter cylindrical portion 73 and the small diameter cylindrical portion 74 are connected at the base of the small diameter cylindrical portion 74 via a connecting portion 75.

[0064] The first gear box 70 is secured by a plurality of screws 76 ( Figure 6 、 7 ) is connected to the large diameter cylinder 73 from the rear. In addition, the rear end of the first gear box 70 is closed by a bracket plate 77 fixed together with screws 76. A coupling gear 78 is held in the large diameter cylinder 73.

[0065] The front end of the rotating shaft 64 passes through a bracket plate 77. The bracket plate 77 holds a bearing 79. The front portion of the rotating shaft 64 is rotatably supported by the bearing 79. A pinion 80 is fixed to the front end of the rotating shaft 64 in the first gear case 70.

[0066] The speed reduction unit 7 is constructed by arranging three stages of carriers 81A to 81C in parallel in the axial direction, each of which supports three planetary gears 82, 82, ... The planetary gears 82 of each stage can revolve within internal gears 83A to 83C.

[0067] The second-stage internal gear 83B is movable in the front-rear direction within the first gear case 70. In the forward position, the internal gear 83B is engaged with the coupling gear 78 and rotation is restricted. In the reverse position, the internal gear 83B is engaged with both the first-stage carrier 81A and the second-stage planetary gears 82.

[0068] The speed switching ring 84 is coupled to the internal gear 83B so as to be movable in the front-rear direction. The speed switching ring 84 is connected to a speed switching lever 85 provided in the window 33 of the intermediate cylinder 30 via front and rear coil springs 86 , 86 .

[0069] When the speed switching lever 85 is slid rearward, the speed switching ring 84 retracts. Consequently, the internal gear 83B meshes with the first-stage carrier 81A while maintaining its meshing with the second-stage planetary gears 82. This results in a high-speed mode (second speed) in which the second-stage reduction gear is canceled.

[0070] Conversely, if the speed switching lever 85 is slid forward, the speed switching ring 84 moves forward. Consequently, the internal gear 83B moves forward, separating from the first-stage carrier 81A. While still meshing with the second-stage planetary gears 82, it meshes with the coupling gear 78, restricting its rotation. This results in a low-speed mode (first speed) in which the second-stage reduction gear function is achieved.

[0071] The mode switching ring 72 is rotatably mounted on the small-diameter cylindrical portion 74 of the second gearbox 71. The output portion 8 can select a vibration drilling mode, a drilling mode, and a clutch mode (screwdriver mode) by rotating the mode switching ring 72. In the vibration drilling mode, the spindle 9 rotates while vibrating in the axial direction. In the drilling mode, the spindle 9 only rotates. In the clutch mode (screwdriver mode), if the clutch operating torque set by the mode switching ring 72 is reached, the rotation transmission from the speed reduction portion 7 to the spindle 9 is cut off.

[0072] The spindle 9 is supported within the small-diameter cylindrical portion 74 by front and rear bearings 90A and 90B. The spindle 9 is capable of axial forward and backward movement. A flange 91 is formed on the front portion of the spindle 9. A coil spring 92 is disposed between the flange 91 and the front bearing 90A. A retaining ring 93 is fixed to the spindle 9 behind the bearing 90A. The spindle 9 is urged toward a forward position where the retaining ring 93 abuts the bearing 90A.

[0073] The rear end of the main shaft 9 is spline-coupled to a lock cam 94. The lock cam 94 is integrally engaged with the third stage gear carrier 81C in the rotational direction.

[0074] An annular first cam 95 and a second cam 96 are disposed within the small-diameter cylindrical portion 74. The first cam 95 is fixed to the rear of the retaining ring 93 and to the main shaft 9. The second cam 96 is externally mounted on the main shaft 9 in a manner such that it can rotate separately from the main shaft 9, with its forward and backward movement restricted behind the first cam 95. Cam surfaces that engage with each other in the rotational direction are formed on the rear surface of the first cam 95 and the front surface of the second cam 96.

[0075] A vibration switching ring 97 and a cam ring 98 are provided outside the small-diameter cylindrical portion 74 and inside the mode switching ring 72. Rotation of the mode switching ring 72 causes the vibration switching ring 97 to move forward and backward via the cam ring 98, engaging and disengaging with the second cam 96. When the vibration switching ring 97 is in the forward position, the rotation of the second cam 96 is restricted. When the vibration switching ring 97 is in the retracted position, the restriction on the rotation of the second cam 96 is released.

[0076] An internal thread portion 100 is provided on the inner circumference of the mode switching ring 72. A spiral feed ring 101 is screwed into the internal thread portion 100. The spiral feed ring 101 is restricted from rotating on the outside of the small-diameter cylinder 74 and can move in the front-to-back direction. A plurality of pressing bosses 102, 102... are provided on the rear part of the spiral feed ring 101 to protrude rearward in the circumferential direction. The front end of the coil spring 103 is externally mounted on each pressing boss 102. A pressing ring 104 is arranged behind each coil spring 103. The pressing ring 104 can move forward and backward along the outer circumference of the small-diameter cylinder 74 and is restricted from rotating. The rear end of each coil spring 103 abuts against the pressing ring 104. On the rear side of the pressing ring 104 and at the connecting portion 75 of the second gear box 71, a plurality of pressing components 105, 105... are held in a manner that allows them to move forward and backward. Each pressing component 105 engages with the front surface of the third-stage internal gear 83C. The internal gear 83C is rotatably provided, and its rotation is restricted by the biasing force of the coil spring 103 via the pressing member 105 .

[0077] (Description of the vibration screwdriver drill action)

[0078] With the vibrating screwdriver drill 1 configured as described above, the operator presses the trigger 41 to turn on the switch 40. When the switch 40 is turned on, the microcomputer in the controller 46 supplies three-phase current to each coil 54 of the stator 50, causing the rotor 51 to rotate. The rotation detection element of the sensor circuit board 60 outputs a rotation detection signal indicating the position of the permanent magnet 63. The microcomputer in the controller 46 controls the on / off switching of each switching element based on the rotation state of the rotor 51 according to the rotation detection signal. The on / off switching of these switching elements sequentially flows current through the coils 54 of each phase of the stator 50. This causes the rotor 51 to rotate continuously, and the rotation of the rotor 51 rotates the rotating shaft 64. The rotation of the rotating shaft 64 rotates the pinion 80, which in turn rotates the main shaft 9 via the speed reduction unit 7. Thus, the drill held by the drill chuck 10 can be used in the selected operation mode.

[0079] Each operation mode is described below.

[0080] First, the mode switching ring 72 is rotated to its leftmost position when viewed from the front. At this position, the vibration switching ring 97 advances. Consequently, the vibration switching ring 97 restricts the rotation of the second cam 96. Meanwhile, the screw feed ring 101 is in its most retracted position, pressing the pressing boss 102 against the pressing ring 104. Consequently, the forward movement of the pressing member 105 is restricted, locking the rotation of the internal gear 83C.

[0081] In this state, the operator presses the drill bit mounted on the drill chuck 10 against the workpiece. This causes the spindle 9 and the drill chuck 10 to move backward together. Consequently, the first cam 95 retracts along with the spindle 9. As the first cam 95 moves backward, it comes into contact with the second cam 96, whose rotation is restricted. Consequently, the first cam 95 and the second cam 96 engage with each other, causing the spindle 9 to rotate along with the drill chuck 10 and the drill bit while vibrating forward and backward. This transitions to vibration drilling mode.

[0082] Next, starting from the vibration drilling mode, the mode switching ring 72 is rotated approximately 10 degrees counterclockwise when viewed from the front. In this rotational position, the vibration switching ring 97 retracts, releasing the rotational restriction on the second cam 96. Meanwhile, the screw feed ring 101 moves slightly forward from its fully retracted position, releasing the pressure of the pressing boss 102 on the pressing ring 104. However, since the forward movement of the pressing ring 104 is minimal, the engagement between the pressing member 105 and the internal gear 83C remains. Consequently, the rotation of the internal gear 83C remains locked.

[0083] In this state, the operator presses the drill bit attached to the drill chuck 10 against the workpiece. This causes the spindle 9 to move rearward along with the drill chuck 10. Consequently, the first cam 95 retracts along with the spindle 9 and contacts the second cam 96. However, the restriction on the rotation of the second cam 96 is released, allowing the second cam 96 to rotate along with the first cam 95. This results in a drilling mode in which the spindle 9 rotates along with the drill chuck 10 and the drill bit without vibrating.

[0084] Next, starting from the drilling mode, the mode switching ring 72 is rotated approximately 30 degrees counterclockwise when viewed from the front. In this rotational position, the vibration switching ring 97 retracts, releasing the restriction on the rotation of the second cam 96. Meanwhile, the screw feed ring 101 moves further forward. Consequently, the pressing member 105 is able to advance against the bias of the coil spring 103 until it is disengaged from the internal gear 83C.

[0085] In this state, the operator presses the drill bit mounted on the drill chuck 10 against the workpiece. This causes the spindle 9 to move rearward along with the drill chuck 10. Consequently, the first cam 95 retracts along with the spindle 9 and contacts the second cam 96. However, the restriction on the rotation of the second cam 96 is released, allowing the second cam 96 to rotate along with the first cam 95. Consequently, the spindle 9 rotates along with the drill chuck 10 and the drill bit without vibrating.

[0086] However, if the torque of the main shaft 9 exceeds the pressing force of the coil spring 103, which maintains the engagement between the internal gear 83C and the pressing member 105, the internal gear 83C relatively passes over the pressing member 105 and rotates idly. This shifts to a clutch mode that cuts off the transmission of rotation to the main shaft 9 at a predetermined torque. If the mode switching ring 72 continues to rotate counterclockwise, the feed ring 101 feeds forward, changing the amount of compression of the coil spring 103. Thus, the torque required to cut off the transmission of rotation can be adjusted.

[0087] Here, a cylindrical housing 11 is used, and the left and right half-shells 12a and 12b of the split housing 12 are fixed to the cylindrical housing 11 by screw fastening. This improves the integrity of the cylindrical housing 11 and split housing 12. This ensures the coaxial accuracy of the stator 50 and rotor 51, and also improves the rigidity of the cylindrical housing 11 that holds the stator 50. This reduces component deflection caused by the magnetic force of the rotor 51, thereby preventing contact between the rotor 51 and the stator 50.

[0088] Meanwhile, fan 67 rotates as shaft 64 rotates. This draws external air into cylindrical housing 11 through air inlet holes 27. The drawn air passes between support ribs 21, 21, and between cylindrical housing 11 and stator 50, flowing rearward. This cools brushless motor 5. The air that has cooled brushless motor 5 is conveyed radially outward from fan 67 and discharged externally through exhaust holes 28.

[0089] (Effects of the Invention of the Integral Cylindrical Housing and the Split Housing Split into Two Parts)

[0090] The vibrating screwdriver drill 1 of the above-described embodiment includes a brushless motor 5 (motor) having a stator 50 and a rotor 51 rotatable relative to the stator 50. Furthermore, the vibrating screwdriver drill 1 includes a first gearbox 70 (gearbox) disposed in front of the brushless motor 5; planetary gears 82 (gears) disposed within the first gearbox 70 to transmit the rotation of the rotor 51; and a main shaft 9 (output shaft) protruding forward from the first gearbox 70 to transmit the rotation from the planetary gears 82. Moreover, the vibrating screwdriver drill 1 comprises: an integral cylindrical outer shell 11, which houses the brushless motor 5 and is open at the front and closed at the rear; a split outer shell 12 (gear box outer shell) divided into two parts on the left and right, which is connected to the front of the cylindrical outer shell 11 to hold the first gear box 70; and a handle 3 (holding outer shell), which extends downward from the split outer shell 12.

[0091] This structure facilitates coaxial arrangement of the stator 50 and the rotor 51. Furthermore, it increases the rigidity of the cylindrical housing 11 that holds the stator 50. Consequently, contact between the rotor 51 and the stator 50 can be effectively prevented.

[0092] (Effects of the invention of a one-piece cylindrical housing and a fan arranged at its bottom)

[0093] The vibrating screwdriver drill 1 of the above embodiment includes a brushless motor 5 having a stator 50; a rotor 51 having a rotating shaft 64 and rotatable relative to the stator 50; and a fan 67 fixed to the rotating shaft 64. Furthermore, the vibrating screwdriver drill 1 includes a cylindrical housing 11 having an integral cylindrical shape, one end of which is open and which houses the brushless motor 5 in an orientation such that the fan 67 is located at the bottom side of the other end; planetary gears 82 (gears) that transmit rotation from the brushless motor 5 to the planetary gears 82; and a main shaft 9 (output shaft) that transmits rotation from the planetary gears 82 to the main shaft 9.

[0094] This structure can reduce the dead space in the rear portion of the cylindrical housing 11. This allows the cylindrical housing 11 to be made more compact. Furthermore, since a rear cover is not used, the number of components and the labor required for assembly can be reduced.

[0095] The split housing 12 includes an intermediate cylinder 30 (cylindrical portion) that fits from the inside into the opening of the cylindrical housing 11. Therefore, the split housing 12 divided into two parts can be joined to the cylindrical housing 11 with high precision.

[0096] The cylindrical housing 11 and the split housing 12 are fixed by screws 69 in the front-rear direction. Therefore, the cylindrical housing 11 and the split housing 12 can be firmly integrated.

[0097] Support ribs 21 (supporting portions) for coaxially supporting the stator 50 are formed on the inner peripheral surface of the cylindrical housing 11. Therefore, the stator 50 can be easily assembled coaxially to the cylindrical housing 11.

[0098] The support portion is formed parallel to the axis of the cylindrical housing 11 and protruding from the cylindrical housing 11 at predetermined intervals. This allows for simple formation of the support portion. Furthermore, a cooling air path for the brushless motor 5 can be ensured between the support ribs 21.

[0099] Positioning ribs 23 (positioning portions) that abut against the stator 50 and position the stator 50 rearward are formed on the rear inner peripheral surface of the cylindrical housing 11. Therefore, the stator 50 can be easily positioned rearward.

[0100] The positioning portion is formed parallel to the axis of the cylindrical housing 11 and is formed at predetermined intervals in the circumferential direction of the cylindrical housing 11. Therefore, the positioning portion can be formed simply.

[0101] The stator 50 is held and stopped by the split housings 12. Therefore, the stator 50 can be stopped by the split housings 12.

[0102] The portion of the stator 50 held between the split housings 12 is an insulator 53A provided on the stator 50. Therefore, the stator 50 can be stopped from rotating by the insulator 53A.

[0103] The rotor 51 has a rotating shaft 64 extending in the front-rear direction. A fan 67 is fixed to the rear of the rotating shaft 64. The cylindrical housing 11 is formed with an air inlet 27 and an air outlet 28. Therefore, a cooling air path for the brushless motor 5 can be easily formed in the cylindrical housing 11.

[0104] A bearing 65 is mounted behind the fan 67 and at the rear end of the rotating shaft 64. The bearing 65 is held by a bearing holding portion 66 formed on the inner bottom surface of the cylindrical housing 11. Therefore, the cylindrical housing 11 can easily support the rotating shaft 64 coaxially.

[0105] The bearing 65 and the bearing holding portion 66 overlap with the fan 67 in the radial direction of the cylindrical housing 11. Therefore, no dead space is generated behind the fan 67, and the cylindrical housing 11 can be made more compact in the axial direction.

[0106] A guide protrusion 24 (guide portion) is provided on the inner peripheral surface of the cylindrical housing 11 . When the bearing 65 is held by the bearing holding portion 66 , the guide protrusion 24 contacts the outer periphery of the fan 67 and guides the fan 67 to a position coaxial with the cylindrical housing 11 .

[0107] Therefore, when the bearing 65 is inserted into the bearing holding portion 66 , the fan 67 is aligned by the guide protrusion 24 , whereby the rotor 51 can be assembled without being affected by the magnetic force of the rotor 51 .

[0108] The guide portion is formed as a plurality of guide protrusions 24 protruding at predetermined intervals in the circumferential direction of the cylindrical housing 11. Each guide protrusion 24 has a front inclined surface 25 (inclined surface) on the front side. This front inclined surface 25 protrudes toward the axial center of the cylindrical housing 11 as it moves from the front to the rear, and the diameter of a concentric circle C passing through the vertex of this protruding side is slightly larger than the outer circumference of the fan 67. Therefore, the front inclined surface 25 can smoothly adjust the center of the fan 67.

[0109] Each guide protrusion 24 is configured to have a rear inclined surface 26 (inclined surface) on the rear side. This rear inclined surface 26 moves radially outward of the cylindrical housing 11 as it moves rearward from the apex. Therefore, when the bearing 65 is retained by the bearing retaining portion 66, the fan 67 moves away from the guide protrusion 24, thereby ensuring a gap between the fan 67 and the guide protrusion 24.

[0110] The outer peripheral surface of the cylindrical housing 11 is provided with a frame portion 18 (engaged portion) into which the engagement portion 35 provided on the split housing 12 engages from the front.

[0111] The fitting portion 35 is divided into two parts, and is provided in halves on the left and right half-split cases 12a and 12b of the split case 12. Therefore, the frame portion 18 can also improve the integrity of the half-split cases 12a and 12b.

[0112] (Effects of the Invention Related to Screw Fastening of Two Integral Cylindrical Housings and Left and Right Split Housings)

[0113] The vibrating screwdriver drill 1 of the above-described embodiment has a housing forming an outer contour, the housing comprising: a cylindrical housing 11 (a first integral cylindrical housing); split housings 12 (left and right split housings) disposed in front of the cylindrical housing 11; and a second gear case 71 (a second integral cylindrical housing) disposed in front of the split housing 12. Furthermore, the vibrating screwdriver drill 1 includes: a brushless motor 5 housed in the cylindrical housing 11; a switch 40 and a controller 46 housed in the split housing 12; an output unit 8 (a power transmission unit) housed in the second gear case 71 and driven by the brushless motor 5; and a drill chuck 10 (a tip tool holder) disposed in front of the second gear case 71 and rotated by the output unit 8. The brushless motor 5 includes a stator 50 whose outer periphery is directly retained by the cylindrical housing 11, and a rotor 51 disposed on the inner periphery of the stator 50. The rear portion of the rotating shaft 64 (rotor shaft) of the rotor 51 is directly retained by the cylindrical housing 11 via a bearing 65. Furthermore, the vibrating screwdriver drill 1 includes a plurality of screws 69 extending in the front-to-rear direction, which are used to secure the cylindrical housing 11, the split housing 12, and the second gear case 71.

[0114] According to this structure, since the divided housing 12 is fastened by being clamped between the front and rear cylindrical housings 11 and the second gear case 71 and screwed together, the rigidity of the housing can be improved.

[0115] A fan 67 is fixed to the rotor 51, and air inlet holes 27 and air outlet holes 28 are formed on the left and right side surfaces of the cylindrical housing 11. The air inlet holes 27 allow air from the fan 67 to flow into the interior of the cylindrical housing 11, while the air outlet holes 28 allow air from the fan 67 to flow out of the cylindrical housing 11. Thus, a cooling air path for the brushless motor 5 can be formed solely within the cylindrical housing 11.

[0116] The front portion of the cylindrical housing 11 is fitted into the rear portion of the split housing 12. Thus, the integrity of the housings is improved.

[0117] (Effects of the Invention in Which the Sensor Circuit Board is Arranged Adjacent to the Opening of the Cylindrical Case)

[0118] The vibrating screwdriver drill 1 of the above-described type has an integral cylindrical housing 11 (motor housing) comprising a cylindrical portion 11a, a plate-shaped portion 11b connected to one end of the cylindrical portion 11a, and an opening 11c disposed at the other end of the cylindrical portion 11a. Furthermore, the vibrating screwdriver drill 1 includes first and second gearboxes 70 and 71 (gear housings) connected to the cylindrical housing 11; an output unit 8 held by the first and second gearboxes 70 and 71; a brushless motor 5 housed in the cylindrical housing 11; a handle 3 connected to the cylindrical housing 11 and housing a switch 40; and a battery mounting portion 4 (battery holding housing) connected to the handle 3 and capable of holding a battery pack 44. Moreover, the brushless motor 5 includes: a stator 50, the outer periphery of which is opposite to the cylindrical portion 11a; a rotor 51, which is arranged on the inner side of the stator 50; a fan 67, which is adjacent to the plate-shaped portion 11b and rotates integrally with the rotor 51; and a sensor circuit substrate 60, which detects the rotation of the rotor 51 and is adjacent to the opening 11c.

[0119] Therefore, the signal line 60 a can be efficiently routed to the brushless motor 5 .

[0120] The sensor circuit board 60 is configured to include a controller 46 for controlling the rotation of the brushless motor 5. A signal line 60a (lead) connects the sensor circuit board 60 and the controller 46. The signal line 60a does not pass through the cylindrical portion 11a or the plate-shaped portion 11b. Therefore, the signal line 60a can be easily routed through the opening 11c.

[0121] (Effects of the invention in which the connecting terminal is arranged adjacent to the opening of the cylindrical housing)

[0122] The vibrating screwdriver drill 1 of the above-described type has an integral cylindrical housing 11 (motor housing) comprising a cylindrical portion 11a, a plate-shaped portion 11b connected to one end of the cylindrical portion 11a, and an opening 11c disposed at the other end of the cylindrical portion 11a. Furthermore, the vibrating screwdriver drill 1 includes first and second gearboxes 70 and 71 (gear housings) connected to the cylindrical housing 11; an output unit 8 held by the first and second gearboxes 70 and 71; a brushless motor 5 housed in the cylindrical housing 11; a handle 3 connected to the cylindrical housing 11 and housing a switch 40; and a battery mounting portion 4 (battery holding housing) connected to the handle 3 and capable of holding a battery pack 44. Moreover, the brushless motor 5 includes: a stator 50, the outer periphery of which is opposite to the cylindrical portion 11a and has a coil 54; a rotor 51, which is arranged on the inner side of the stator 50; a fan 67, which is close to the plate-shaped portion 11b and rotates integrally with the rotor 51; and a connecting terminal 55a, which is connected to the coil 54 and is adjacent to the opening 11c.

[0123] Therefore, the power supply line 55 b can be efficiently routed to the brushless motor 5 .

[0124] The structure includes a control circuit board 47 (switching element board) for energizing the brushless motor 5. A power line 55b (lead) connects the connection terminal 55a to the control circuit board 47. The power line 55b does not pass through the cylindrical portion 11a or the plate-shaped portion 11b. Therefore, the power line 55b can be easily routed through the opening 11c.

[0125] (Explanation of Changes)

[0126] In each invention, the number and position of the supporting ribs and positioning ribs provided on the inner circumference of the cylindrical housing can be varied as appropriate. Protrusions other than ribs can also be used as the supporting portion. The positioning portion is also not limited to rib shapes. The cylindrical housing and split housings can be configured in the reverse manner described above, with the front end of the cylindrical housing mating with the rear end of the split housing.

[0127] The stator is not limited to being locked by the split housings holding the locking piece provided on the insulator. The stator may be locked by engaging a protrusion formed on the inner circumference of the cylindrical housing with the stator.

[0128] The fan guide protrusion may be provided with an inclined surface only on the front side and not on the rear side. The number and position of the guide protrusions may also be changed as appropriate. The guide portion may also be provided with a shape other than a protrusion.

[0129] It is possible to provide only the exhaust holes in the cylindrical housing and provide the air intake holes in the divided housings.

[0130] The cylindrical housing may be formed into a structure composed of two or more layers of materials.

[0131] The AC tool may be one that uses an AC power source instead of a battery pack.

[0132] In the invention involving a single-piece cylindrical housing and a split housing divided into two parts, as well as the invention involving screw fastening between the two single-piece cylindrical housings and the split housings, the motor is not limited to a brushless motor. The number and position of the screws that screw fasten the housings in the front-to-back direction may also be varied.

[0133] The integral cylindrical motor housing does not necessarily need to hold the rear portion of the rotor shaft. This is because the conventional problem of the left and right split housings being unable to firmly hold the stator has been improved.

[0134] Either the left or right split housing can hold the rear portion of the rotor shaft. In this case, the stator and rotor shaft, supported by either split housing, can be easily coaxially arranged. Conventionally, this was difficult due to the use of a rear cover separate from the left or right split housing, but this has been improved.

[0135] The electric rotary tool may be a screwdriver or drill without a vibration mechanism. It may also use an electronic clutch instead of a mechanical clutch. It may also be an electric screwdriver or an electric drill.

[0136] It may be an AC tool that uses an AC power source instead of a battery pack.

[0137] The invention, which includes a cylindrical housing with an integral cylindrical shape and a fan located at its bottom, can be used as an electric rotary tool, such as a screwdriver or drill without a vibration mechanism. Alternatively, an electronic clutch may be used instead of a mechanical clutch. Alternatively, the invention can be an electric screwdriver or electric drill.

[0138] However, the electric rotary tool is not limited to the T-shaped body formed by the front-back direction and the handle in the up-down direction. Other electric rotary tools such as reciprocating saws and circular saws can also adopt the present invention. Therefore, the split housing does not need to be split into two parts.

[0139] In the invention in which the sensor circuit board or the connection terminal is arranged adjacent to the opening of the motor housing, the sensor circuit board may not be provided. In this case, the lead wires can also be easily routed from the connection terminal.

[0140] The switching element may be mounted on the sensor circuit board instead of the control circuit board. In this case, three power supply lines extend from the sensor circuit board.

[0141] In the above configuration, the sensor circuit board and connection terminals protrude from the opening (toward the front). This is not limiting; the sensor circuit board and connection terminals can also be placed inside the motor housing (further behind the opening). In this case, wiring can also be easily routed.

Claims

1. An electric rotary tool, characterized in that: This electric rotary tool features: a motor having a stator and a rotor rotatable relative to the stator; a gear box, the gear box being arranged in front of the motor; a gear disposed inside the gear box and to which the rotation of the rotor is transmitted; an output shaft that projects forward from the gear case and to which rotation is transmitted from the gear; an integral cylindrical housing, which houses the motor and is open at the front and closed at the rear; a gear box housing divided into two parts, the gear box housing being connected to the front of the cylindrical housing and holding the gear box; and A holding housing extending downward from the gear box housing, A support portion that coaxially supports the stator is formed on the inner peripheral surface of the cylindrical housing.

2. The electric rotary tool according to claim 1, wherein: The gear box housing includes a cylindrical portion that is fitted into the opening of the cylindrical housing from the inside.

3. The electric rotary tool according to claim 1 or 2, characterized in that: The cylindrical housing and the gear box housing are fixed together using screws in a front-rear direction.

4. The electric rotary tool according to claim 1, wherein: The support portion is a support rib formed parallel to the axis of the cylindrical housing and protruding at predetermined intervals in the circumferential direction of the cylindrical housing.

5. An electric rotary tool, characterized in that: This electric rotary tool features: a motor having a stator and a rotor rotatable relative to the stator; a gear box, the gear box being arranged in front of the motor; a gear disposed inside the gear box and to which the rotation of the rotor is transmitted; an output shaft that projects forward from the gear case and to which rotation is transmitted from the gear; an integral cylindrical housing, which houses the motor and is open at the front and closed at the rear; a gear box housing divided into two parts, the gear box housing being connected to the front of the cylindrical housing and holding the gear box; and A holding housing extending downward from the gear box housing, A positioning portion is formed on the rear inner peripheral surface of the cylindrical housing and contacts the stator to position the stator rearward.

6. The electric rotary tool according to claim 5, wherein: The positioning portions are positioning ribs formed parallel to the axis of the cylindrical housing and formed at predetermined intervals in the circumferential direction of the cylindrical housing.

7. The electric rotary tool according to claim 5, wherein: The stator is clamped by the gear box housing to prevent rotation.

8. The electric rotary tool according to claim 7, wherein: The portion of the stator held by the gearbox housing is an insulating member provided on the stator.

9. The electric rotary tool according to claim 5, wherein: The rotor has a rotation shaft extending in a front-to-rear direction, the fan is fixed to the rear of the rotation shaft, and an air inlet and an air outlet are formed in the cylindrical housing.

10. The electric rotary tool according to claim 9, wherein: A bearing is mounted behind the fan and at the rear end of the rotary shaft. The bearing is held by a bearing holding portion formed on the inner bottom surface of the cylindrical housing.

11. The electric rotary tool according to claim 10, wherein: The bearing and the bearing holding portion overlap with the fan in a radial direction of the cylindrical housing.

12. The electric rotary tool according to claim 10 or 11, characterized in that: A guide portion is provided on the inner peripheral surface of the cylindrical housing. When the bearing is held by the bearing holding portion, the guide portion contacts the outer periphery of the fan and guides the fan to a position coaxial with the cylindrical housing.

13. The electric rotary tool according to claim 12, wherein: The guide portion is a plurality of guide protrusions protrudingly arranged at specified intervals in the circumferential direction of the cylindrical shell, each of the guide protrusions having an inclined surface on the front side, the inclined surface protruding toward the axial center side of the cylindrical shell as it moves from the front to the rear, and the diameter of the concentric circles passing through each vertex of the protruding side is slightly larger than the outer circumference of the fan.

14. The electric rotary tool according to claim 13, wherein: Each of the guide protrusions has an inclined surface on a rear side, and the inclined surface moves toward the radially outer side of the cylindrical housing as it goes rearward from the apex.

15. The electric rotary tool according to claim 5, wherein: An engaged portion into which an engaging portion provided on the gear box housing engages from the front is provided on the outer peripheral surface of the cylindrical housing.

16. The electric rotary tool according to claim 15, wherein: The fitting portion is divided into two parts in the left-right direction, and the halves are respectively provided on the left and right half-split housings of the gear box housing.

17. An electric rotary tool, characterized in that: The electric rotary tool has: a housing constituting an outer contour and comprising a first integral cylindrical housing, left and right split housings disposed on the front side of the first integral cylindrical housing, and a second integral cylindrical housing disposed on the front side of the left and right split housings; a motor housed in the first integral cylindrical housing; A switch and a controller, the switch and the controller being housed in the left and right divided housings; a power transmission unit housed in the second integral cylindrical housing and driven by the motor; and a tip tool holding portion, which is arranged on the front side of the second integral cylindrical housing and rotated by the power transmission portion; The motor includes a stator whose outer periphery is directly held by the first integral cylindrical housing; and a rotor arranged on the inner periphery of the stator and whose rotor shaft is directly held by the first integral cylindrical housing via a bearing. The electric rotary tool includes a plurality of screws extending in the front-rear direction, and the plurality of screws are used to fix the first integral cylindrical housing, the left and right split housings, and the second integral cylindrical housing.

18. The electric rotary tool according to claim 17, wherein: A fan is fixed to the rotor. An air inlet hole and an air exhaust hole are formed on the left and right sides of the first integral cylindrical shell. The air inlet hole is used to allow the wind based on the fan to flow into the interior of the first integral cylindrical shell, and the air exhaust hole is used to allow the wind based on the fan to flow out of the first integral cylindrical shell.

19. The electric rotary tool according to claim 17 or 18, characterized in that: The front portion of the first integral cylindrical housing is fitted with the rear portions of the left and right divided housings.

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