Power tool

Abstract

The present application provides an electric power tool having a speed reduction unit that is compact in the axial direction and enables smooth and stable speed switching. The impact driver has a speed reduction unit (75) that reduces the rotation generated by a motor, the speed reduction unit (75) having an inner gear (81A) that is rotatable, and an inner gear (81B) that is rotatable and has a different speed reduction ratio from the inner gear (81A). The speed reduction unit (75) has a speed switching plate (110) that is disposed radially outward of the inner gears (81A, 81B), is switchable to a rearward tilt posture in which the inner gear (81A) is locked to restrict rotation of the inner gear (81A), and a forward tilt posture in which the inner gear (81B) is locked to restrict rotation of the inner gear (81B). Furthermore, the speed reduction unit (75) has a speed switching ring (114) and a speed switching dial that are capable of selectively switching the speed switching plate (110) to either the rearward tilt posture or the forward tilt posture.

Description

Technical Field

[0001] This invention relates to power tools equipped with a speed reduction unit. Background Technology

[0002] Regarding power tools such as impact screwdrivers, a speed reduction unit is used to reduce the rotation of the motor and transmit the reduced rotation to the output shaft of the anvil or similar component. Patent Document 1 discloses a speed reduction unit that includes multiple planetary gears forming multiple stages, a gear carrier supporting the planetary gears, and an internal gear with internal teeth that cause the planetary gears to revolve. With this speed reduction unit, the meshing state between one internal gear and the gear carrier and planetary gears is changed by moving one of the internal gears along the axial direction, thereby enabling speed changes.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-98450 Summary of the Invention

[0006] In conventional transmission mechanisms that move the internal gear, the travel distance of the internal gear must be ensured, which hinders compactness in the axial direction. Furthermore, the internal gear tilts relative to the axial direction during movement, preventing smooth meshing and sometimes hindering smooth gear shifting.

[0007] Therefore, the object of the present invention is to provide an electric tool having a reduction section that is compact in the axial direction and can smoothly and stably switch speeds.

[0008] To achieve the above objectives, the first aspect of the present invention is a power tool, which has:

[0009] motor;

[0010] A speed reduction unit that reduces the rotational speed generated by the motor; and

[0011] The working part operates by means of rotation reduced in speed by the reduction unit.

[0012] The reduction unit has at least two stages of internal gears, planetary gears that revolve within the internal gears, and a gear carrier that supports the planetary gears in the axial direction.

[0013] The power tool is characterized in that...

[0014] The deceleration unit has:

[0015] A rotatable front-side internal gear, wherein the front-side internal gear is the internal gear located at the front;

[0016] A rotatable rear-side internal gear, wherein the rear-side internal gear is located at the rear of the front-side internal gear and has a different reduction ratio than the front-side internal gear;

[0017] A locking component is disposed radially outside the front-side internal gear and the rear-side internal gear, and is capable of switching between a first position where it is locked to the front-side internal gear to restrict its rotation, and a second position where it is locked to the rear-side internal gear to restrict its rotation; and

[0018] The operation unit is capable of selectively switching the locking component to either the first position or the second position.

[0019] To achieve the above objectives, the second aspect of the present invention is an electric tool, characterized by having:

[0020] motor;

[0021] A gear carrier that rotates by means of the motor;

[0022] A pin, which is held in the gear carrier;

[0023] A first planetary gear, which is held on the pin and has a first number of teeth;

[0024] A second planetary gear, which is held on the pin and has a second number of teeth different from the first number of teeth;

[0025] A first internal gear, which meshes with the first planetary gear;

[0026] A second internal gear, which meshes with the second planetary gear; and

[0027] A fixing component that prevents either the first internal gear or the second internal gear from rotating.

[0028] Invention Effects

[0029] According to the present invention, a speed reduction section can be provided that is compact in the axial direction and can perform smooth and stable speed switching. Attached Figure Description

[0030] Figure 1 This is a side view of an impact screwdriver.

[0031] Figure 2 This is a top view of an impact screwdriver.

[0032] Figure 3 This is a rear view of an impact screwdriver.

[0033] Figure 4 It is a three-dimensional view of an impact screwdriver as seen from the rear.

[0034] Figure 5 This is an illustration of an impact screwdriver where the right half of the outer casing is omitted, and the main body is shown in the central longitudinal section.

[0035] Figure 6 This is a partial 3D view of an impact screwdriver after the back cover has been removed. Figure 6 A is shown from the front in a partial three-dimensional view. Figure 6 B is shown from the rear in a partial three-dimensional view.

[0036] Figure 7 yes Figure 1 Enlarged cross-sectional view of line A-A.

[0037] Figure 8 It is an exploded three-dimensional view of the main body of the outer shell.

[0038] Figure 9 This is an explanatory diagram of the work unit. Figure 9 A shows the side view. Figure 9 B shows the front side.

[0039] Figure 10 yes Figure 9 Enlarged cross-sectional view of the C-C line of B.

[0040] Figure 11 yes Figure 9 Enlarged cross-sectional view of the D-D line of B.

[0041] Figure 12 A is Figure 9 A partial cross-sectional view of the E-E line of B. Figure 12 B is Figure 9 A partial cross-sectional view of line F-F of B. Figure 12 C is Figure 9 A partial cross-sectional view of the G-G line of B.

[0042] Figure 13 yes Figure 1 Enlarged cross-sectional view of the B-B line.

[0043] Figure 14 This is an exploded three-dimensional view of the deceleration unit as seen from the rear.

[0044] Figure 15 A shows Figure 10 H-H line cross section, Figure 15 B shows Figure 10 The I-I line cross section, Figure 15 C shows Figure 10 The J-J line cross section.

[0045] Figure 16 A shows Figure 10 K-K line cross section, Figure 16 B shows Figure 10 The L-L line cross section, Figure 16 C shows Figure 10 The M-M line cross section.

[0046] Figure 17 This is an exploded three-dimensional view of the deceleration unit as seen from the front.

[0047] Figure 18 A shows Figure 10 N-N line cross section, Figure 18 B shows Figure 10 O-O line cross section, Figure 18 C shows Figure 10 The cross section of the P-P line.

[0048] Figure 19 This is an explanatory diagram showing the selected working unit (level 1) in drilling mode. Figure 19 A represents a plane. Figure 19 B shows the side view. Figure 19 C indicates the bottom surface. Figure 19 D indicates the horizontal cross section. Figure 19 E indicates the central longitudinal section.

[0049] Figure 20 This is an explanatory diagram showing the selected working unit at speed 2 in vibration drilling mode. Figure 20 A represents a plane. Figure 20 B shows the side view. Figure 20 C indicates the bottom surface. Figure 20 D indicates the horizontal cross section. Figure 20 E indicates the central longitudinal section.

[0050] Figure 21 This is an explanatory diagram of the working unit in the high-impact mode (gear 3). Figure 21 A represents a plane. Figure 21 B shows the side view. Figure 21 C indicates the bottom surface. Figure 21 D indicates the horizontal cross section. Figure 21 E indicates the central longitudinal section.

[0051] Figure 22 This is an explanatory diagram of the working unit in low-impact mode (4th gear). Figure 22 A represents a plane. Figure 22 B shows the side view. Figure 22 C indicates the bottom surface. Figure 22 D indicates the horizontal cross section. Figure 22E indicates the central longitudinal section.

[0052] Figure 23 It is an exploded 3D view of the striking section.

[0053] Figure 24 A shows Figure 10 The Q-Q line cross section, Figure 24 B shows Figure 10 The R-R line cross section, Figure 24 C shows Figure 10 The S-S line cross section.

[0054] Figure 25 This is an exploded three-dimensional view of the vibrating part.

[0055] Figure 26 A shows Figure 10 The T-T line cross section, Figure 26 B shows Figure 10 U-U line cross section, Figure 26 C shows Figure 10 The V-V line cross section.

[0056] Figure 27 This is a three-dimensional view of the working unit from below.

[0057] Figure 28 yes Figure 10 Enlarged cross-sectional view of the W-W line.

[0058] Figure 29 This is an explanatory diagram of the cutter head assembly structure. Figure 29 Figure A shows the situation when the blade is inserted. Figure 29 B shows the situation during the assembly of the cutting head. Figure 29 C shows the situation when the blade is pulled out.

[0059] Figure 30 A is a central longitudinal section view of the working unit showing the state of the inner hammer retracting at its maximum stroke under the large impact mode. Figure 30 B is the X-ray cross-sectional view.

[0060] Figure 31 A is a longitudinal section view of the anvil portion equipped with a nail-driving blade. Figure 31 B is an exploded 3D view of a nail-driving blade.

[0061] Explanation of reference numerals in the attached figures

[0062] 1. Impact screwdriver, 2. Main body, 3. Handle, 4. Motor, 5. Working unit, 6. Mode conversion ring, 7. Hammer housing, 8. Anvil, 9. Speed ​​switching dial, 10. Main body shell, 11. Rear cover, 12. Main body section, 13. Grip section, 25. Controller, 30. Cover section, 31. Screw fastening section, 53. Rotary shaft, 60. Rear gear housing, 61. Front gear housing, 74. Input gear, 75. Reduction section, 76. Strike section, 77. Vibration section, 78. Linkage switching section, 80A~80C. Planetary gears, 81A~81C. Internal gears, 85. Rear gear carrier, 106. Speed ​​switching retainer, 11 0··Speed ​​switching plate, 114··Speed ​​switching ring, 120··Plane gear ring, 126··Upper gear, 130··Front gear carrier, 145··Speed ​​switching wire, 151··Speed ​​switching gear, 153··Speed ​​switching retainer, 165··Spindle, 166··Inner hammer, 167··Outer hammer, 168··Hammer sleeve, 169··Outer disc spring, 170··Inner disc spring, 216··Connecting ball, 230··Front side cam, 231··Rear side cam, 234··Vibration switching plate, 280··Mode conversion lever, 285··Mode conversion shift fork, 295··Linkage winding part, 301··Linkage lever, 305··Linkage cam, B··Cutter head, B1··Nail driving cutter head. Detailed Implementation

[0063] In one embodiment of the present invention, the locking member is configured such that its middle portion is supported and its two ends are swayable. In a first position, one end is locked to the outer periphery of the front-side internal gear, and in a second position, the other end is locked to the outer periphery of the rear-side internal gear. According to this structure, space can be saved by using one locking member, and the rotational restriction and release of two internal gears can be reasonably performed.

[0064] In one embodiment of the present invention, the deceleration unit may be housed within a cylindrical housing. In this case, the operating unit may include an annular member configured to rotate around the outer periphery of the housing, and alternately formed in the circumferential direction with a first pressing portion that presses one end of the locking member from the radially outer side of the housing to switch the locking member to a first position, and a second pressing portion that presses the other end of the locking member from the radially outer side to switch the locking member to a second position. In this case, the deceleration unit may also include a rotation operating member that allows the annular member to rotate at any angle around the outer periphery of the housing. According to this structure, space can be saved and the posture switching of the locking member can be easily performed using the annular member and the rotation operating member.

[0065] In one embodiment of the present invention, the annular member may have a plurality of teeth continuously formed circumferentially, and the rotary operating member may have a gear integrally formed thereon that meshes with the teeth. According to this structure, the annular member can be easily rotated by rotating the rotary operating member.

[0066] In one embodiment of the present invention, a toothed gear ring may be integrally provided on the annular component. According to this structure, teeth can be easily provided on the annular component.

[0067] In one embodiment of the present invention, the annular member can be formed as a frame-like body in which the first pressing portion and the second pressing portion protrude differently in the axial direction and meander in the circumferential direction. According to this structure, the structure of the annular member becomes simple.

[0068] In one embodiment of the present invention, multiple locking components may be provided. According to this structure, the rotation of the internal gear can be reliably restricted.

[0069] In one embodiment of the invention, the locking member can be configured at a point symmetrical about the axis of the internal gear. According to this structure, the rotation of the internal gear can be restricted without tilting it relative to the axis.

[0070] In one embodiment of the present invention, a plurality of locking ribs extending along the axial direction are provided at predetermined intervals along the circumference of the front-side internal gear and the rear-side internal gear. In this case, locking portions that lock onto the locking ribs in the circumferential direction are formed at both ends of the locking member. According to this structure, the rotation restriction and release of the internal gear can be reliably performed.

[0071] In one embodiment of the invention, the locking portion can be formed in a curled shape. According to this structure, it is easy to lock into place with the locking rib.

[0072] In one embodiment of the present invention, the front-side internal gear and the rear-side internal gear may be arranged adjacent to each other in the axial direction, and a sealing member may be sandwiched between their opposing surfaces. In this case, flange portions extending toward the center may be formed at the ends of the opposing surfaces of the front-side internal gear and the rear-side internal gear, respectively. According to this structure, a retaining space is formed between the two internal gears to prevent grease from overflowing outwards from the radially inner side of the internal gears, thereby preventing the grease from drying out.

[0073] In one embodiment of the present invention, the reduction unit may be configured to have another internal gear rotatably. In this case, the other internal gear may be configured to slide in a first sliding position where its rotation is restricted in the axial direction within the housing housing the reduction unit, causing the planetary gears to revolve, and in a second sliding position where it is not restricted from rotation within the housing and simultaneously meshes with the planetary gears and the gear carrier. Furthermore, it may be configured such that by combining the restriction of rotation of either the front-side internal gear or the rear-side internal gear based on the locking member with the sliding position of the other internal gear, three or more speed levels can be selected. According to this structure, even a mechanical reduction unit can achieve three or more speed levels.

[0074] Example

[0075] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0076] (Overview of impact screwdriver and description of its casing structure)

[0077] Figure 1 This is a side view of a rechargeable impact screwdriver, which is an example of a work tool, a power tool, and further, an impact tool. Figure 2 This is a top view of an impact screwdriver. Figure 3 This is a rear view of an impact screwdriver. Figure 4 It is a three-dimensional view of an impact screwdriver as seen from the rear. Figure 5 This is an illustration of an impact screwdriver where the right half of the outer casing is omitted, and the main body is shown in the central longitudinal section.

[0078] The impact screwdriver 1 has a body 2 and a handle 3. The body 2 has a central shaft formed in the front-rear direction. A motor 4 and a working unit 5 are arranged inside the body 2. The working unit 5 has a mode conversion ring 6 exposed to the outside at the front. A hammer housing 7 is provided on the front side of the mode conversion ring 6 and exposed to the front. The working unit 5 has an anvil 8 protruding forward from the center of the hammer housing 7. A speed switching dial 9 is provided on the upper surface of the working unit 5 in a rotatable manner and protruding upward. The handle 3 protrudes downward from the body 2. A rubber bumper 43 is fitted on the front surface of the hammer housing 7.

[0079] The impact screwdriver 1 has a main body housing 10, a rear cover 11, and a hammer housing 7 as its outer casing. The main body housing 10 includes a main body portion 12, a grip portion 13, a protective portion 14, and a battery mounting portion 15. The main body portion 12 is cylindrical and forms the middle portion of the main body 2 excluding the front and rear ends. Multiple air inlets 16, 16... are formed on the left and right rear portions of the main body portion 12. The main body portion 12 holds the motor 4 and the working unit 5, and exposes the mode conversion ring 6 and the hammer housing 7 on the front side.

[0080] The grip portion 13 extends downwards from the rear end of the main body 12, forming the rear side of the handle 3. A switch 17 is provided at the upper end of the grip portion 13. The switch 17 causes the trigger 18 to protrude forward. The grip portion 13 is located at the rear end of the main body 12. Therefore, it is easy to grip the base of the grip portion 13 and press the main body 2 forward. A forward / reverse switching button 19 for the motor 4 is provided above the switch 17.

[0081] The protective part 14 is formed downwards from the front end of the main body 12, forming the front side of the handle 3. The protective part 14 is formed with a width smaller than that of the grip part 13, and overlaps with the grip part 13 when viewed from the front. The upper end of the protective part 14 forms a raised part 20 that extends in a curved shape from the front of the main body 2 to the lower part of the anvil 8. A lamp 21 is provided at the upper end of the raised part 20. The lamp 21 illuminates the front of the anvil 8. A wiring storage space 22 is formed inside the protective part 14. The wiring storage space 22 stores wires (not shown) that are electrically connected to, for example, the controller 25 and the lamp 21, and even sensors, as described later.

[0082] The battery mounting section 15 connects the lower end of the grip section 13 and the lower end of the protective section 14. Accordingly, the handle 3 is formed in a ring shape. The battery pack 23, which serves as the power source, is slidably mounted on the battery mounting section 15 from the front. A terminal block 24 and a controller 25 are provided in the battery mounting section 15. The battery pack 23 is electrically connected to the terminal block 24. The controller 25 has a control circuit board 26. The controller 25 performs various controls such as controlling the motor 4 and monitoring the remaining charge of the battery pack 23. In addition, the controller 25 also has an electronic clutch function, that is, when the output torque reaches or exceeds a specified value, the rotation of the motor 4 is stopped.

[0083] A display unit 27 is provided on the inner side of the protective section 14. The display unit 27 is electrically connected to the control circuit board 26 via wires (not shown). The display unit 27 displays the remaining power of the battery pack 23, the number of stages of the electronic clutch, etc. The display unit 27 is formed by a touch panel, and the number of stages of the electronic clutch can be selected by touching the display unit 27.

[0084] The main body shell 10 and the rear cover 11 are made of resin. The main body shell 10 is divided into left and right halves 10a and 10b, and is assembled together from the right side by a plurality of screws 28, 28...

[0085] The rear cover 11 includes a cover portion 30 and a screw fastening portion 31. The cover portion 30 is circular when viewed from the rear. Figure 6 As shown, the cover 30 covers and connects to the cylindrical portion 32 formed at the rear end of the main body 12 from the rear. Multiple vents 33, 33... are formed on the circumferential surface of the cover 30. Each vent 33 is an elongated oval extending circumferentially from the cover 30. However, in the upper half of the cover 30, as... Figure 7 As shown, one circumferentially longer exhaust port 33A (referred to as "33A" for distinction) is formed on each side. In the lower half of the cover 30, two circumferentially shorter exhaust ports 33B (referred to as "33B" for distinction) are formed on each side. Regarding the two exhaust ports 33A and 33A in the upper half, their circumferentially adjacent inner edges 34a and 34a are formed in the vertical direction. Their circumferentially separated inner edges 34b and 34b are formed in the horizontal direction. The inner edges of the four exhaust ports 33B in the lower half are formed in the horizontal direction, parallel to the inner edges 34b.

[0086] A fan 35 is disposed inside the cover 30 and mounted on the rotating shaft 53 of the motor 4. Regardless of whether the fan 35 rotates forward or backward, air is guided upward by the inner edges 34a and 34a at the two exhaust ports 33A and 33A.

[0087] A screw fastening portion 31 is formed downward from the lower part of the cover portion 30. An anti-rotation portion 36 extending vertically is provided on the rear surface of the main body portion 12 and protruding below the cylindrical portion 32. An internal thread portion 37 is formed on the upper center side of the anti-rotation portion 36. A through hole 38 opening at the rear is formed below the internal thread portion 37. The through hole 38 is used for the passage of wiring from the grip portion 13 below and inside the main body 2.

[0088] The screw fastening part 31 has a pair of ribs 39, 39 on its front surface that engage with the anti-rotation part 36 from the left and right sides. A circular through hole 40 is provided between the ribs 39, 39.

[0089] Accordingly, when assembling the rear cover 11, the cover portion 30 is fitted into the cylindrical portion 32, and the ribs 39, 39 of the screw fastening portion 31 are fitted into the anti-rotation portion 36. In this state, the screw 41, which passes through the rear through hole 40, is screwed into the internal thread portion 37. Thus, the rear cover 11 is assembled using only one screw 41.

[0090] (Explanation of the entity's internal structure)

[0091] Motor 4 is an internal rotor type brushless motor with a stator 45 and a rotor 46. Insulating components 47 are provided before and after the stator 45. Figure 8 As shown, two positioning recesses 48, 48 are formed on the left and right sides of the front insulating member 47, respectively. A terminal unit 49 is provided at the lower part of the front insulating member 47. The terminal unit 49 is electrically connected to a plurality of coils 50, 50... wound around the stator 45 by means of the insulating members 47, 47. A wire is connected to the terminal unit 49 and disposed between it and the controller 25.

[0092] Two locking claws 51, 51 protrude from the inner surfaces of the left and right semi-circular outer shells 10a, 10b forming the main body 12 and engage with the positioning recesses 48, 48. Support ribs 52 are provided behind the locking claws 51, 51 and on the inner surfaces of the semi-circular outer shells 10a, 10b, respectively, along the circumference of the stator 45. Accordingly, the stator 45 is held at the rear of the main body 12.

[0093] The rotor 46 has a centrally located rotating shaft 53 through which the stator 45 passes. The rear end of the rotating shaft 53 is supported at the center of the cover 30 of the rear cover 11 by means of a bearing 54. The fan 35 is disposed on the rotating shaft 53 in front of the bearing 54, thereby overlapping the bearing 54 radially. A pinion 55 is formed at the front end of the rotating shaft 53.

[0094] like Figure 9 and Figure 10 , Figure 11 As shown, the working unit 5 includes a rear gear housing 60 and a front gear housing 61.

[0095] The rear gear housing 60 is formed as a bottomed cylindrical shape with its rear surface closed by a rear plate portion 62 and an open front end. The front gear housing 61 is formed as a bottomed cylindrical shape with its front surface closed by a front plate portion 63 and an open rear end. The front gear housing 61 has a larger diameter than the rear gear housing 60, and its rear end opening is externally fitted to the front end of the rear gear housing 60. Two rear stops 64, 64( ), are formed on the left and right sides of the rear gear housing 60, respectively, for the rear end of the front gear housing 61 to abut against. Figure 8 , Figure 9 (A). Half-cylinder portions 65 and 65 are provided between the rear stops 64 and 64 and on the left and right sides of the rear gear housing 60 in the front-rear direction, so that the front is open.

[0096] Front stop members 66 and 66 are formed on the left and right sides of the front gear housing 61, respectively, and abut against the semi-cylinder portions 65 and 65 from above. Accordingly, the front gear housing 61 is in a state in which rearward movement is restricted by the rear stop member 64 and circumferential rotation is restricted by the semi-cylinder portion 65.

[0097] like Figure 12 A and Figure 13 As shown, the hammer housing 7 is fixed to the front plate 63 from the rear by a plurality of screws 67, 67... The mode conversion ring 6 is supported so that it can rotate between the front plate 63 and the hammer housing 7.

[0098] Four rear locking recesses 68, 68... are provided on the front part of the rear gear housing 60 and on its left and right sides respectively. The rear locking recesses 68 are provided at predetermined intervals along the front-rear direction in the circumferential direction of the rear gear housing 60. Furthermore... Figure 8 and Figure 13As shown, two front locking recesses 69 are arranged circumferentially on the upper front part of the front gear housing 61 and on the rear side of the mode conversion ring 6. Each front locking recess 69 opens to the left and right outwards.

[0099] Four rear-side locking portions 70, 70... are provided on the rear part of the main body 12 and on the inner surface of the left and right half-cut outer shells 10a, 10b, which are locked to each of the rear-side locking recesses 68. Two front-side locking portions 71, 71 are provided on the front part of the main body 12 and on the inner surface of the left and right sides, which are locked to each of the front-side locking recesses 69.

[0100] Accordingly, the front and rear locking portions 70 and 71 are respectively locked into the front and rear locking recesses 68 and 69, thereby keeping the working unit 5 in the main body 12 in a state where its rotation and forward and backward movement are restricted.

[0101] In particular, such as Figure 13 As shown, the front gear housing 61 is clamped to the left and right half-shells 10a and 10b at a position higher than when viewed from the front axis in the left-right direction. Accordingly, it is possible to ensure that a large linkage switching part 78 with a circumferential angle of more than 180° is provided on the lower side of the clamping part and between the front gear housing 61 and the main body 12.

[0102] A thick-walled portion 72, which is circular in frontal view, is formed at the center of the rear plate portion 62 of the rear gear housing 60. An input gear 74 is held in the thick-walled portion 72 by means of a bearing 73. The input gear 74 is configured such that it meshes with the rear portion of a pinion 55 of the rotating shaft 53, thereby enabling it to rotate integrally with the rotating shaft 53. The input gear 74 has a first gear portion 74a on its rear side and a second gear portion 74b on its front side, with a diameter smaller than that of the first gear portion 74a.

[0103] The working unit 5 is provided with a deceleration unit 75, a striking unit 76, a vibration unit 77, and a linkage switching unit 78 for linking and switching these working units from the rear. These will be described in turn below.

[0104] (1) Description of the deceleration section

[0105] The reduction gear 75 is disposed within the rear gear housing 60. Also, Figure 14 As shown, the reduction unit 75 has three planetary gears 80, 80... arranged in the axial direction to form three stages, and an internal gear 81 for meshing with each planetary gear 80. The reduction ratio is different for each stage. Hereinafter, starting from the last stage (first stage), the gears will be described sequentially as 80A (first stage), 80B (second stage), and 80C (third stage), labeled with symbols A to C. A engagement ring 82 is provided between the internal gear 81B of the second stage and the internal gear 81C of the third stage.

[0106] like Figure 10 , Figure 11 , Figure 15 As shown in Figure A, each planetary gear 80A of the first stage meshes with the first gear portion 74a of the first stage internal gear 81A and the input gear 74. Each planetary gear 80A has a gear portion 83 on the rear side and a small-diameter bearing portion 84 on the front side.

[0107] The planetary gears 80B of the second stage are externally mounted on the bearing portion 84 of the planetary gears 80A. Accordingly, the planetary gears 80A and 80B of the first and second stages overlap each other radially. Furthermore... Figure 15 As shown in C, the planetary gear 80B meshes with the internal gear 81B of the second stage and the second gear section 74b of the input gear 74.

[0108] A disc-shaped rear gear carrier 85 is provided on the front side of the planetary gear 80B. The rear gear carrier 85 has three pins 86, 86... protruding rearward. The bearing portion 84 of the planetary gear 80A is supported by the pins 86 by means of bearings (here, needle roller bearings) 87. The spur gear 88 engages with the center spline of the rear gear carrier 85 and protrudes forward.

[0109] In this way, the planetary gears 80A and 80B, which rotate in the same direction by means of the input gear 74, overlap each other radially, thereby shortening the shaft length including the two planetary gears 80A and 80B and thus shortening the pin 86. Only one bearing 87 needs to be provided. In addition, the contact length between the planetary gear 80A and the pin 86 can be shortened, thereby reducing mechanical losses caused by frictional resistance.

[0110] Specifically, the support portion of planetary gear 80B is designed as the bearing portion 84 of planetary gear 80A, thereby making the relative angular velocity between planetary gear 80A and planetary gear 80B slower than the relative angular velocity between planetary gear 80B and pin 86. This reduces mechanical losses during deceleration using planetary gear 80B. In other words, the mechanical losses are reduced when planetary gear 80B contacts the non-rotating pin 86 compared to when it contacts planetary gear 80A, which rotates in the same direction even at a slower speed.

[0111] The first-stage internal gear 81A is rotatably mounted on the front side of the rear plate portion 62 of the rear gear housing 60, separated by a washer 89. A rear flange portion 90, with a reduced diameter towards the center, is formed on the rear side of the internal teeth of the internal gear 81A. The rear flange portion 90 is close to the outer peripheral surface of the thick-walled portion 72 of the rear plate portion 62. Multiple rear retaining ribs 91, 91... are provided on the outer periphery of the internal gear 81A. Figure 14 and Figure 15 As shown in Figure A, the rear retaining ribs 91 are arranged at equal intervals in the circumferential direction along the front-rear direction. An annular retaining groove 92 is coaxially formed on the front surface of the internal gear 81A. (See Figure A for details.) Figure 15 As shown in B, the retaining groove 92 houses the O-ring 93.

[0112] The second-stage internal gear 81B has more internal teeth than the internal gear 81A. The internal gear 81B is adjacent to the internal gear 81A in the axial direction and is pressed against the O-ring 93. The internal gear 81B is also configured to rotate.

[0113] A front flange 94, with a reduced diameter towards the center, is formed on the front side of the internal teeth of the internal gear 81B. The front flange 94 is close to the outer peripheral surface of the rear gear carrier 85. Furthermore... Figure 14 and Figure 16 As shown in Figure A, a plurality of front locking ribs 95 are provided on the outer periphery of the internal gear 81B. The front locking ribs 95 are arranged in the front-rear direction at the same intervals as the rear locking ribs 91 in the circumferential direction.

[0114] Thus, as Figure 11 As shown, a retaining space S is formed between the internal gears 81A and 81B by the rear flange 90, the front flange 94, and the O-ring 93, preventing grease from overflowing outwards from the radially inner side of the internal gears 81A and 81B. This prevents the grease from drying out. It should be noted that even if the grease dries out, lubrication can be maintained because the bearing 87 of the planetary gear 80A is a needle roller bearing.

[0115] The engaging ring 82 is housed within the rear gear housing 60 on the front side of the internal gear 81B. The engaging ring 82 has multiple engaging claws 100, 100... on its outer circumference. Each engaging claw 100 is equally spaced circumferentially and protrudes radially outward, extending forward. Figure 16 B and Figure 17 As shown, a plurality of engaging grooves 101, 101... are provided on the inner circumferential surface of the rear gear housing 60. Each engaging groove 101 extends from the front end of the rear gear housing 60 to the rear. Each engaging claw 100 of the engaging ring 82 engages with each engaging groove 101 from the front.

[0116] Accordingly, the engagement ring 82 is restricted from rotating within the rear gear housing 60. Protrusions 102, 102 protruding radially outward are provided on the left and right sides of the engagement ring 82 and on the outer surfaces of the engagement claws 100, 100. The protrusions 102, 102 engage with through holes 108, 108 provided in the speed switching retainers 106, 106 (described later). The speed switching retainers 106, 106 have their forward and backward movement restricted within the rear gear housing 60 by the bracket plate 136 (described later). Accordingly, the forward movement of the engagement ring 82 is restricted, and the forward movement of the internal gears 81A, 81B is also restricted.

[0117] Openings 103, 103 are formed on the left and right sides of the rear gear housing 60 and on the rear side of the semi-cylindrical portions 65, 65 in the front-rear direction. Slits 104, 104 are formed on the inner side of the semi-cylindrical portions 65, 65 in the front-rear direction. Each slit 104 opens at the front end of the rear gear housing 60.

[0118] like Figure 17 and Figure 18 As shown in Figure A, a pair of grooves 105, 105 extending in the front-rear direction are formed inside the openings 103, 103 and on the inner circumferential surface of the rear gear housing 60. Speed ​​switching retainers 106, 106 are provided in the grooves 105, 105. The speed switching retainer 106 is formed as a plate that fits into the groove 105 and extends in the front-rear direction. A pair of square holes 107, 107 are formed at the rear of the speed switching retainer 106. The square holes 107, 107 are located inside the openings 103, 103. A through hole 108 is formed on the front side of the square holes 107, 107 and on the speed switching retainer 106 for the protrusion 102 of the engagement ring 82 to be engaged. An inner slit 109 is formed at the front of the through hole 108, cutting into the rear from the front end of the speed switching retainer 106.

[0119] Speed ​​switching plates 110 are provided on the rear outer side of the speed switching retainers 106, 106. The speed switching plate 110 is a plate-shaped structure that spans the front and rear of the speed switching retainer 106 through square holes 107, 107 and extends in the front-rear direction. For example... Figure 11 As shown, regarding the speed switching plate 110, the central portion in the front-to-back direction abuts against the spacer wall 111 between the square holes 107, 107 of the speed switching retainer 106. A rear locking portion 112 and a front locking portion 113 are provided at both the front and rear ends of the speed switching plate 110. The two locking portions 112 and 113 are formed such that they are bent into a coiled shape towards the center side of the rear gear housing 60.

[0120] Accordingly, each speed switching plate 110 can alternately swing inward within the opening 103 of the rear gear housing 60, using its central portion abutting against the partition wall 111 as a fulcrum. The outer periphery of the first-stage internal gear 81A is located inside the rear locking portion 112. When the rear locking portion 112 swings inward toward the rear gear housing 60, it can be locked against the rear locking rib 91 by means of the rear square hole 107. At this time, the opposite front locking portion 113 protrudes outward beyond the opening 103 and separates from the outer periphery of the internal gear 81A. The outer periphery of the second-stage internal gear 81B is located inside the front locking portion 113. When the front locking portion 113 swings inward toward the rear gear housing 60, it can be locked against the front locking rib 95 by means of the front square hole 107. At this time, the opposite rear locking portion 112 protrudes outward beyond the opening 103 and separates from the outer periphery of the internal gear 81B.

[0121] A speed switching ring 114 is rotatably disposed on the outer side of the speed switching plate 110 and on the outer periphery of the rear gear housing 60. The speed switching ring 114 is a frame-shaped body that extends meanderingly in the front-rear direction and is continuous in the circumferential direction. The speed switching ring 114 includes: 10 rear pressing portions 115, 115... extending circumferentially on the rear side; and 10 front pressing portions 116, 116... extending circumferentially on the front side. The rear pressing portions 115 and the front pressing portions 116 are arranged alternately in the circumferential direction, and adjacent pressing portions 115, 116 are connected to each other by inclined portions 117, 117... A virtual circle including each rear pressing portion 115 is located outside the rear locking portions 112, 112 of the speed switching plates 110, 110. A virtual circle including each front pressing portion 116 is located outside the front locking portions 113, 113 of the speed switching plates 110, 110.

[0122] Accordingly, when the speed switching ring 114 rotates, it alternately switches between a phase where the rear pressing part 115 is located outside the rear end of the speed switching plate 110 and a phase where the front pressing part 116 is located outside the front end of the speed switching plate 110. If the rear pressing part 115 is located outside the rear end of the speed switching plate 110, the rear pressing part 115 presses the rear end of the speed switching plate 110 inward. Accordingly, the speed switching plate 110 swings to a backward tilted position where the rear locking part 112 engages with the rear locking rib 91 of the first-stage internal gear 81A. As a result, the rotation of the internal gear 81A is restricted. On the other hand, if the front pressing part 116 is located outside the front end of the speed switching plate 110, the front pressing part 116 presses the front end of the speed switching plate 110 inward. Accordingly, the speed switching plate 110 swings to a forward tilted position where the front locking part 113 engages with the front locking rib 95 of the second-stage internal gear 81B. As a result, the rotation of the internal gear 81B is restricted. The left and right speed switching plates 110 oscillate synchronously.

[0123] Between two phases, as the tilting part 117 passes outside the speed switching plate 110, it presses the speed switching plate 110 inward, causing it to change between a forward tilting posture and a backward tilting posture.

[0124] A planar gear ring 120 is attached to the front of the speed switching ring 114. The planar gear ring 120 is a ring with the same diameter as the speed switching ring 114. Multiple forward-projecting teeth 121, 121… are continuously formed at equal intervals along the circumferential direction on the front surface of the planar gear ring 120. Multiple slits 122, 122… are formed on the rear surface of the planar gear ring 120. Each slit 122 corresponds to a front pressing portion 116 of the speed switching ring 114. Each front pressing portion 116 has a fitting protrusion 123 that engages with the corresponding slit 122. Accordingly, the planar gear ring 120 and the speed switching ring 114 are integrated in the rotational direction.

[0125] The speed switching dial 9 is used to rotate the speed switching ring 114. The speed switching dial 9 appears as a disc when viewed from above. Figure 10 As shown, an upper support protrusion 124 protrudes upward from the upper surface of the rear gear housing 60. A receiving hole 125 for inserting the upper support protrusion 124 is formed at the center of the lower surface of the speed switching dial 9. Accordingly, the speed switching dial 9 can rotate around the upper support protrusion 124. An upper gear 126 is coaxially disposed on the lower surface of the speed switching dial 9. Furthermore... Figure 18 As shown in Figure A, the upper gear 126 meshes with the teeth 121 of the planar gear ring 120. A knob portion 127 is provided protruding along the diametrical direction on the upper surface of the speed switching dial 9.

[0126] For example Figure 16 As shown in Figure C, the planetary gears 80C of the third stage are positioned on the front side of the rear gear carrier 85 and mesh with the spur gear 88. Each planetary gear 80C is supported on the disc-shaped front gear carrier 130 by means of pins 131, 131... Here, the axial length of the pin 131 is shortened, allowing the planetary gear 80C and the front gear carrier 130 to directly abut. Accordingly, the bending moment of the pin 131 is reduced, making it less prone to breakage.

[0127] Multiple external engagement teeth 132, 132... are formed on the outer periphery of the front gear carrier 130. The rear end of the main shaft 165, described later, is splined into the center of the front gear carrier 130. Due to the splined connection, it is less susceptible to torsion from the main shaft 165. Consequently, it is difficult to apply impact loads biased towards the gears or pins from the main shaft 165 side, thus improving the durability of the reduction gear 75. Figure 10 and Figure 17 As shown, an annular recess 133 is formed around the main shaft 165 and on the front surface of the front gear carrier 130.

[0128] The third-stage internal gear 81C is configured to move back and forth within the rear gear housing 60. Multiple engaging ribs 134, 134… are provided on the rear outer periphery of the internal gear 81C. The engaging ribs 134 have the same number (10) as the engaging claws 100 of the engaging ring 82. An annular groove 135 is formed on the front outer periphery of the internal gear 81C.

[0129] When the internal gear 81C is in the retracted position, it maintains meshing with the planetary gear 80C, causing the engaging rib 134 to engage with the engaging pawl 100 of the engaging ring 82 in the circumferential direction. This restricts the rotation of the internal gear 81C. When the internal gear 81C is in the forward position, as... Figure 11 As shown, the engagement ring 82 separates, allowing the internal teeth to mesh with the planetary gear 80C and the external engagement teeth 132 of the front gear carrier 130.

[0130] A bracket plate 136 is provided on the front side of the internal gear 81C. The bracket plate 136 supports the rear end of the main shaft 165 by means of a bearing 137. The bracket plate 136 has a rearwardly protruding annular bearing locking portion 138 on the outer periphery of the holding portion of the bearing 137. The bracket plate 136 has a plurality of engaging protrusions 139, 139... at equal intervals along the circumferential direction. Each engaging protrusion 139 engages with the wide portion 140 at the front end of each engaging groove 101 provided on the inner circumferential surface of the rear gear housing 60. Figure 17 The bracket plate 136 is engaged with the gear housing 60. Accordingly, the rotation and rearward movement of the bracket plate 136 within the rear gear housing 60 are restricted.

[0131] like Figure 10 As shown, the bearing locking portion 138 protrudes into a recess 133 provided on the front surface of the front gear carrier 130. Accordingly, the front gear carrier 130 and the bearing locking portion 138 overlap radially, thus becoming compact in the axial direction. An annular clearance recess 141 is also formed on the front surface of the bracket plate 136 and on the outer peripheral side of the bearing 137. Figure 17 ).

[0132] like Figure 11 and Figure 18As shown in Figure A, the speed switching cable 145 engages with the groove 135 of the third-stage internal gear 81C. The speed switching cable 145 is located on the lower outer side of the front gear housing 61. The speed switching cable 145 is semi-circular in the main view, with its left and right ends forming rearward-folded portions 146, 146. The folded portions 146, 146 are inserted from the front into the left and right semi-cylindrical portions 65, 65 of the rear gear housing 60. The rear ends of the folded portions 146, 146 form locking ends 147, 147 that bend towards the center of the rear gear housing 60 within the semi-cylindrical portions 65, 65. After passing through the slits 104, 104 of the rear gear housing 60, the locking ends 147, 147 pass through the inner slits 109, 109 of the speed switching retainers 106, 106, thereby engaging with the groove 135 of the internal gear 81C. At the lower part of the speed switching cable 145 and in the center of the left-right direction, there is a pair of U-shaped protrusions 148, 148 protruding downwards.

[0133] On the left and right sides of the bracket plate 136, the outer peripheral surfaces of the engaging protrusions 139, 139 are provided with anti-disengagement protrusions 149, 149. The anti-disengagement protrusions 149, 149 are located in front of the slits 104, 104 of the rear gear housing 60 to prevent the locking ends 147, 147 from disengaging.

[0134] like Figure 10 and Figure 14 As shown, a lower support protrusion 150 is provided protruding downwards on the lower surface of the rear gear housing 60. The lower support protrusion 150 is configured to be coaxial with the upper support protrusion 124. A speed switching gear 151 is externally mounted to the lower support protrusion 150 in a rotatable manner. The speed switching gear 151 is formed with the same size and number of teeth as the upper gear 126 of the speed switching dial 9, and meshes with the teeth 121 of the planar gear ring 120. An eccentric pin 152 is provided protruding downwards at an eccentric position on the lower surface of the speed switching gear 151.

[0135] A speed switching retainer 153 is provided on the lower side of the speed switching gear 151. The speed switching retainer 153 is supported by a support seat 42 formed on the inner bottom surface of the main body 12. Figure 5 , Figure 8 The speed switching retainer 153 is a plate extending in the front-to-back direction, with an elongated hole 154 extending in the left-to-right direction formed at its rear. The eccentric pin 152 of the speed switching gear 151 is inserted into the elongated hole 154 from above. The central portion of the elongated hole 154 in the left-to-right direction becomes a circular portion 155 that bulges out in the front-to-back direction. The rear end of the speed switching retainer 153 becomes a stop 156 that bends upward to the side.

[0136] A guide protrusion 157 is provided on the front side of the elongated hole 154 and on the upper surface of the speed switching retainer 153, facing upwards. The guide protrusion 157 extends in the left-right direction.

[0137] A pair of retaining plates 159, 159 are integrally formed on the front side of the guide protrusion 157 and on the front part of the speed switching retainer 153. The retaining plates 159, 159 extend in the left-right direction at intervals in the front-back direction. A pair of connecting plates 160, 160 are formed between the retaining plates 159, 159, extending in the front-back direction and connecting the retaining plates 159, 159 to each other. The protrusions 148, 148 of the speed switching cable 145 engage with the connecting plates 160, 160 from below. Accordingly, the speed switching cable 145 is held between the retaining plates 159, 159 and is integrally formed with the speed switching retainer 153 in the front-back direction.

[0138] Regarding the deceleration unit 75, the upper speed switching dial 9 is rotated via the knob 127. This causes the planar gear ring 120 and the speed switching ring 114 to rotate via the upper gear 126. Here, when the speed switching dial 9 is rotated 90°, the planar gear ring 120 and the speed switching ring 114 rotate 18°. Accordingly, each time the speed switching dial is rotated 90°, the rotation alternates between a backward-tilting position of the speed switching plates 110 and 110 based on the rear pressing parts 115 and 115, and a forward-tilting position of the speed switching plates 110 and 110 based on the front pressing parts 116 and 116. That is, each time the upper gear 126 rotates 90°, the rotation restriction of the first-stage internal gear 81A based on the rear pressing part 115 and the rotation restriction of the second-stage internal gear 81B based on the front pressing part 116 is switched.

[0139] When the upper gear 126 rotates, the speed switching gear 151 also rotates in the opposite direction simultaneously via the planar gear ring 120. This rotational amount (angle) is the same as that of the upper gear 126. Consequently, the eccentric pin 152 undergoes an eccentric movement, causing the speed switching retainer 153 to slide in the forward-backward direction via the elongated hole 154. Accordingly, the speed switching wire 145 moves forward and backward integrally, causing the locking end 147 to engage with the third-stage internal gear 81C in the groove 135, allowing it to slide forward and backward. Here, each time the upper gear 126 rotates 180°, the speed switching retainer 153 slides forward or backward. Accordingly, the internal gear 81C switches between forward and backward positions via the speed switching wire 145.

[0140] The left and right ends of the speed switching cable 145 are bent rearwards into folded portions 146 and 146, which are inserted from the front ends of the semi-cylindrical portions 65 and 65 and extend rearwards. This allows the internal gear 81C to move linearly in the axial direction. Furthermore, the semi-cylindrical portions 65 and 65 prevent the bent portions 146 and 146 from bending outwards, thus making it difficult for the locking ends 147 and 147 to disengage from the groove 135. In addition, since the semi-cylindrical portions 65 and 65 are only open at the front, grease leakage is unlikely.

[0141] Thus, regarding the reduction gear 75, with each 90° rotation of the speed shift dial 9, the rotational restriction and release of the internal gears 81A and 81B of the first and second stages, and the forward and backward position of the internal gear 81C of the third stage, are combined to select gears 1 through 4. Numbers 1 through 4, representing speeds, are marked on the upper surface of the speed shift dial 9 every 90°. Cutouts 161 are formed radially outward of each number and on the outer periphery of the speed shift dial 9. A leaf spring 162 (in the left-right direction) is held on the upper surface of the front gear housing 61. Figure 9 , Figure 14 It can be locked at the cut 161. Accordingly, a clicking effect can be obtained whenever the speed switching dial 9 rotates 90°.

[0142] In addition, such as Figure 14 and Figure 16 As shown in Figure A, a plurality of click recesses 118, 118... are formed on the outer periphery of the rear gear housing 60. Click protrusions 119, which engage with the click recesses 118 in the rotational direction, are formed on the inner periphery of each rear pressing portion 115 and each front pressing portion 116 of the speed switching ring 114. Therefore, when the speed switching ring 114 rotates, a clicking action is achieved through the engagement of the click recesses 118 and the click protrusions 119.

[0143] Figure 19 The first gear is shown. The rotation position of the speed switch dial 9 is as follows: Figure 19 As shown in Figure D, the speed switching plate 110 is in a forward-tilted position. Accordingly, the rotation of the second-stage internal gear 81B is restricted, while the first-stage internal gear 81A rotates freely. At this time, as... Figure 19 As shown in Figure C, the speed switching gear 151 is in a first rotational position such that the eccentric pin 152 is located to the left rear. Accordingly, the speed switching retainer 153 is in a retracted position, and the third-stage internal gear 81C is also in a retracted position. Accordingly, the internal gear 81C engages with the engagement ring 82 and is restricted from rotation.

[0144] The rotation input from input gear 74 is transmitted to the first-stage planetary gear 80A and the second-stage planetary gear 80B. However, the first-stage internal gear 81A rotates freely, while the rotation of the second-stage internal gear 81B is restricted. Accordingly, planetary gear 80A does not revolve, only the second-stage planetary gear 80B, which has a larger reduction ratio, revolves within the internal gear 81B. The rotation of the rear gear carrier 85, caused by the revolution of planetary gear 80B, is transmitted to the third-stage planetary gear 80C, causing it to revolve within the internal gear 81C. The rotation of the front gear carrier 130, caused by the revolution of planetary gear 80C, is transmitted to the main shaft 165.

[0145] Figure 20 Two speed settings are shown. The speed selector dial 9 rotates 90° to the right from setting 1 when viewed from above. In this rotated position, the planar gear ring 120 rotates 18°, causing the speed selector plate 110 to tilt backward. Accordingly, the rotation of the first-stage internal gear 81A is restricted, while the second-stage internal gear 81B rotates freely. At this time, the speed selector gear 151 rotates 90° to the left when viewed from above, as... Figure 20 As shown in Figure C, the eccentric pin 152 is in a second rotational position with its rear right side positioned. Accordingly, the retracted position of the speed switching retainer 153 remains unchanged, and the internal gear 81C is also restricted from rotation in the retracted position where it engages with the engagement ring 82. It should be noted that when the eccentric pin 152 rotates 90°, it moves along a rearward-bulging arc-shaped trajectory. However, the central portion of the elongated hole 154 of the speed switching retainer 153 has an increased front-to-back width due to the circular portion 155, thus allowing rotation of the eccentric pin 152. Furthermore, excessive load is not applied to the speed switching retainer 153.

[0146] Accordingly, the rotation input from the input gear 74 is transmitted to planetary gears 80A and 80B. However, planetary gear 80B does not revolve; only the first-stage planetary gear 80A, with its relatively small reduction speed, revolves within the internal gear 81A. The rotation of the rear gear carrier 85, caused by the revolution of planetary gear 80A, is transmitted to the third-stage planetary gear 80C, causing it to revolve within the internal gear 81C. The rotation of the front gear carrier 130, caused by the revolution of planetary gear 80C, is transmitted to the main shaft 165 at a speed greater than that of first gear.

[0147] Figure 21 Three speed settings are shown. The speed selector dial 9 rotates 90° to the right from setting 2 when viewed from above. In this rotated position of the speed selector dial 9, the planar gear ring 120 rotates 18°, causing the speed selector plate 110 to assume the same forward-tilted posture as in setting 1. Accordingly, the rotation of the second-stage internal gear 81B is restricted, while the first-stage internal gear 81A rotates freely.

[0148] At this moment, the speed switching gear 151 rotates 90° to the left from gear 2 when viewed from above, as follows: Figure 21 As shown in C, the eccentric pin 152 is in a third rotational position, positioned to the right front. Accordingly, the speed switching retainer 153 moves to a forward position, causing the internal gear 81C to move forward via the speed switching wire 145. In this forward position, the freely rotating internal gear 81C causes the third-stage planetary gear 80C and the front gear carrier 130 to become integrated in the rotational direction.

[0149] Accordingly, the rotation input from the input gear 74 is transmitted to planetary gears 80A and 80B. However, planetary gear 80A does not revolve; only the second-stage planetary gear 80B, which experiences a relatively large reduction, revolves within the internal gear 81B. The rotation of the rear gear carrier 85, caused by the revolution of planetary gear 80B, is transmitted from the third-stage planetary gear 80C through the internal gear 81C to the front gear carrier 130. Therefore, the reduction in the third stage is canceled, and the rotation of the front gear carrier 130 is transmitted to the main shaft 165 at a speed greater than that of second gear.

[0150] Figure 22 Four speed settings are shown. The speed selector dial 9 rotates 90° to the right from speed 3 when viewed from above. In this rotated position of the speed selector dial 9, the planar gear ring 120 rotates 18°, causing the speed selector plate 110 to assume the same backward tilt as in speed 2. Accordingly, the rotation of the first-stage internal gear 81A is restricted, while the second-stage internal gear 81B rotates freely.

[0151] At this moment, the speed switching gear 151 rotates 90° to the left from gear 3 when viewed from above, as follows: Figure 22 As shown in C, the eccentric pin 152 is in the fourth rotational position, which positions it to the left front. Accordingly, the speed switching retainer 153 and the internal gear 81C are still in the forward position.

[0152] Accordingly, the rotation input from the input gear 74 is transmitted to planetary gears 80A and 80B. However, planetary gear 80B does not revolve; only the first-stage planetary gear 80A, with its smaller reduction speed, revolves within the internal gear 81A. The rotation of the rear gear carrier 85, caused by the revolution of planetary gear 80A, is transmitted from the third-stage planetary gear 80C to the front gear carrier 130 via the internal gear 81C. Consequently, the rotation of the front gear carrier 130 is transmitted to the main shaft 165 at a speed greater than that of the third gear.

[0153] In this way, the gear shifting stage of the reduction unit 75 can be selected by rotating the speed switching dial 9. However, in a specific operating mode, the reduction unit 75 automatically switches to a specific gear shifting stage through the linkage action of the linkage switching unit 78 accompanying the rotation of the mode switching ring 6. This linkage action will be further explained below.

[0154] (2) Explanation of the batting section

[0155] like Figure 10 , Figure 11 , Figure 23 As shown, the striking part 76 includes a main shaft 165, an inner hammer 166, an outer hammer 167, a hammer sleeve 168, an outer disc spring 169, an inner disc spring 170, and an anvil 8.

[0156] The striking part 76, except for the front part of the anvil 8, is housed within the front gear housing 61. The anvil 8 extends through the front plate portion 63 of the front gear housing 61. A bearing 171 supporting the anvil 8 is held in the front plate portion 63. A pair of radially protruding arms 172 are provided within the front gear housing 61 and at the rear end of the anvil 8.

[0157] The rear of the spindle 165 is supported by the bracket plate 136 and extends forward. A small-diameter portion 173 is formed at the front end of the spindle 165. A bottomed hole 174 is formed at the rear axis of the anvil 8 for the small-diameter portion 173 to fit into. In the forward position of the anvil 8, where the arm portion 172 abuts against the front plate portion 63, a gap is formed between the front surface of the spindle 165 other than the small-diameter portion 173 and the rear surface of the anvil 8. Accordingly, the anvil 8 can move rearward accordingly with respect to the gap.

[0158] A through hole 175 is formed along the entire length of the spindle 165. A ball bearing 176 is housed in front of the through hole 175. A reduced-diameter section 177 is formed behind the ball bearing 176 and in the through hole 175. A coil spring 178 is provided between the ball bearing 176 and the reduced-diameter section 177, thereby pressing the ball bearing 176 against the inner surface of the bottom hole 174. Accordingly, force is applied to the anvil 8 in its forward position under normal conditions.

[0159] A flange 179 is formed in front of the bracket plate 136 and behind the main shaft 165. A pair of inner cam grooves 180, 180 are formed behind the small diameter portion 173 and in front of the main shaft 165. The inner cam grooves 180 are formed in a V-shape with the tip pointing forward.

[0160] The inner hammer 166 is cylindrical and externally mounted on the front of the main shaft 165. A pair of forward-protruding claws 181, 181 are formed on the front surface of the inner hammer 166. The claws 181, 181 engage with the arms 172, 172 of the anvil 8 in the rotational direction. A pair of outer cam grooves 182, 182 extending from the front end to the rear are provided on the inner circumferential surface of the inner hammer 166. Cam balls 183, 183 are fitted between the outer cam grooves 182, 182 and the inner cam groove 180 of the main shaft 165. Accordingly, the inner hammer 166 is engaged with the main shaft 165 by means of the cam balls 183, 183. The inner hammer 166 is capable of relative movement with respect to the main shaft 165 in the back-and-forth and rotational directions within a range that allows the cam balls 183 to rotate between the inner cam groove 180 and the outer cam groove 182.

[0161] An annular groove 184 is formed on the rear surface of the inner hammer 166. A plurality of (6) interlocking grooves 185, 185... are formed on the circumferential surface of the inner hammer 166 and near the rear end. The interlocking grooves 185 are formed at equal intervals in the circumferential direction of the inner hammer 166 and extend in the front-rear direction.

[0162] The outer hammer 167 is a bottomed cylindrical shape with an opening at the front and is externally mounted to the rear of the main shaft 165. The outer hammer 167 includes a base plate portion 190, an inner cylinder portion 191, and an outer cylinder portion 192. The center of the base plate portion 190 is penetrated by the main shaft 165. The inner cylinder portion 191 protrudes forward from the inner periphery of the base plate portion 190. The outer cylinder portion 192 protrudes forward from the outer periphery of the base plate portion 190. The outer cylinder portion 192 is longer and extends forward further than the inner cylinder portion 191.

[0163] An annular inner groove 193 is formed on the outer periphery of the inner surface of the base plate portion 190. For example... Figure 18 As shown in B, multiple balls 194, 194... are housed throughout the circumference of the inner groove 193. The balls 194 receive the rear end of the outer disc spring 169 through a washer 195. The rear end of the inner disc spring 170 abuts against the inner surface of the base plate 190 on the inside side of the balls 194.

[0164] An annular protrusion 196 is formed on the rear surface of the base plate portion 190, which contacts the rear of the inner groove 193. The protrusion 196 protrudes into the clearance recess 141 on the front surface of the bracket plate 136. Accordingly, the bracket plate 136 and the base plate portion 190 overlap radially, thereby becoming compact in the axial direction.

[0165] An annular recess 197 is formed on the inner circumferential surface of the inner cylinder 191 from the rear end to the front. The recess 197 faces the flange 179 of the main shaft 165 from the front. A neck 198 is formed on the front side of the flange 179 and on the outer circumference of the main shaft 165. A plurality of balls 199, 199... are fitted around the entire circumference of the neck 198. The balls 199 abut against the inner surface of the front end of the recess 197 and receive the inner cylinder 191 in the axial direction. A retaining ring 200 is engaged on the front side of the inner cylinder 191 and on the main shaft 165. Accordingly, the outer hammer 167 is connected to the main shaft 165 in a state where the inner cylinder 191 is restricted from moving back and forth between the balls 199 and the retaining ring 200, and is rotatable relative to the inner cylinder 191.

[0166] Multiple (six) retaining slits 201, 201... are formed in the outer cylinder section 192. For example... Figure 18 As shown in Figure C, the retaining slits 201 are arranged at equal intervals in the circumferential direction of the outer cylinder portion 192 and extend in the front-rear direction. Each retaining slit 201 is located radially outward of the inner fitting groove 185 of the inner hammer 166. However, the retaining slits 201 are formed to be longer than the inner fitting groove 185 in the front-rear direction. Also as... Figure 24 As shown in Figure B, a plurality of hemispherical recesses 202, 202... are formed circumferentially on the outer cylinder portion 192 and between the retaining slits 201, 201... A ball bearing 203 is fitted into each recess 202. Figure 10 , Figure 11 and Figure 24 As shown, support grooves 204, 204, ... are formed on the inner side of the retaining slits 201, 201... and on the inner circumferential surface of the outer cylinder 192 along the front-rear direction. Each support groove 204 is formed longer from the front end of the outer cylinder 192 toward the rear than the retaining slit 201.

[0167] The hammer sleeve 168 is a sleeve component externally mounted to the outer hammer 167. A plurality of (6) external fitting grooves 210, 210... are formed on the inner circumferential surface of the hammer sleeve 168. Each external fitting groove 210 is arranged at equal intervals along the circumference of the hammer sleeve 168 and extends along the entire length of the hammer sleeve 168. However, the radial depth of each external fitting groove 210 is configured as follows: Figure 18 The shallowest rear groove 211 shown in C, as... Figure 24 A and Figure 24 The middle groove 212 shown in B is deeper than the rear groove 211, as... Figure 24The front groove 213, which is deeper than the middle groove 212 as shown in C, gradually increases in depth towards the front. The outer fitting groove 210 is located radially outward of the retaining slit 201 of the outer hammer 167. In the circumferential direction and between the outer fitting grooves 210, 210..., a plurality of engagement grooves 214, 214..., which are shorter than the outer fitting grooves 210 in the front-rear direction, are formed from the front end of the hammer sleeve 168 toward the rear. A ball 203 that has been engaged with the recess 202 of the outer hammer 167 is fitted into each engagement groove 214. Accordingly, the outer hammer 167 and the hammer sleeve 168 are integrated in the rotational direction. However, the hammer sleeve 168 can move back and forth by the stroke of the ball 203 relative to each other in the engagement groove 214. An annular groove 215 is formed on the rear outer periphery of the hammer sleeve 168.

[0168] In the radially overlapping inner fitting grooves 185 of the inner hammer 166, the retaining slits 201 and support grooves 204 of the outer hammer 167, and the outer fitting grooves 210 of the hammer sleeve 168, multiple (5) engaging balls 216, 216... are respectively fitted across each groove and slit. To maintain this engagement, multiple U-shaped clamping members 220, 220... are respectively engaged on the front side of the 5 engaging balls 216 and within the retaining slits 201, 201... Each clamping member 220 is inserted from the rear into the front end of the retaining slit 201 with both ends facing forward and the short side along the radial direction of the outer cylinder portion 192 of the outer hammer 167. Figure 24 As shown in C, the inner end 221 of each clamping member 220 on the radially inner side is engaged with the support groove 204 of the outer cylinder portion 192. The outer end 222 of each clamping member 220 on the radially outer side is engaged with the outer fitting groove 210 of the hammer sleeve 168.

[0169] Accordingly, the inner hammer 166 and the outer hammer 167 are connected in the front-rear direction by a connecting ball bearing 216, such that the front part of the outer cylinder 192 is externally mounted on the inner hammer 166. However, in the rotational direction, the front-rear position of the hammer sleeve 168 is switched between an integral structure and a split structure.

[0170] The outer disc spring 169 and the inner disc spring 170 are double-mounted externally to the main shaft 165 between the inner hammer 166 and the outer hammer 167. The front end of the outer disc spring 169 abuts against the rear surface of the inner hammer 166 on the outside of the groove 184.

[0171] The inner spring 170 is formed by winding a wire with a diameter larger than that of the outer spring 169 in the opposite direction to the outer spring 169. The front end of the inner spring 170 is inserted into the groove 184 of the inner hammer 166. A washer 223 and multiple balls 224, 224... are housed on the front inner surface of the groove 184 to receive the front end of the inner spring 170. Figure 24 B).

[0172] The outer disc spring 169 and the inner disc spring 170 are used to position the inner hammer 166 such that the cam ball 183 is located at the tip of the inner cam groove 180 of the main shaft 165 and at the rear end of the outer cam groove 182 of the inner hammer 166. Figure 10 and Figure 11 Apply force to the forward position.

[0173] Grease grooves 225, 225... are respectively provided on the inner circumferential surface of the bottom hole 174 of the anvil 8, the inner circumferential surface of the inner hammer 166, and the inner circumferential surface of the inner cylinder 191 of the outer hammer 167. Each grease groove 225 is annular, covering the entire circumference of each inner circumferential surface.

[0174] Specifically, the grease grooves 225 on the inner circumferential surface of the anvil 8 with the bottom hole 174 and the inner circumferential surface of the inner hammer 166 are arranged at predetermined intervals in the front-back direction. By providing multiple grease grooves 225 on the inner circumferential surface, the grease is dispersed between each inner circumferential surface and the shaft inside it, thereby maintaining lubrication.

[0175] A connecting hole 226, which communicates with the through hole 175, is formed in the middle of the main shaft 165 and behind the inner cam groove 180 along the diametrical direction. The connecting hole 226 communicates with one of the grease grooves 225 of the inner hammer 166 in the forward position.

[0176] Regarding the striking unit 76, the hammer sleeve 168 moves back and forth by rotating the mode switching ring 6, thereby switching between a state in which striking can be performed and a state in which striking cannot be performed.

[0177] At the retracted position of the hammer sleeve 168, such as Figure 22 As shown in Figure E, the deepest front groove 213 of the outer fitting groove 210 is located outside the retaining slit 201 of the outer hammer 167. Therefore, when centrifugal force is applied, the five engaging balls 216 engage with the front groove 213, the retaining slit 201, and the support groove 204, and disengage from the inner fitting groove 185 of the inner hammer 166. Accordingly, only the inner hammer 166 generates the striking force.

[0178] At the middle position after the hammer sleeve 168 has moved forward from the retracted position, such as Figure 21 As shown in Figure E, the central groove 212 of the outer fitting groove 210 is located outside the retaining slit 201. Therefore, for the five engaging balls 216, when centrifugal force is applied, the three outer engaging balls 216 are fitted across the central groove 212 and the retaining slit 201. The two inner engaging balls 216 are fitted across the support groove 204 and the inner fitting groove 185 of the retaining slit 201. Accordingly, the inner hammer 166, the outer hammer 167, and the hammer sleeve 168 are integrated into one unit to generate an impact force.

[0179] After the hammer sleeve 168 moves forward from the middle position, the forward position is as follows: Figure 19 E and Figure 20 As shown in Figure E, the rear groove 211 and the middle groove 212 of the outer fitting groove 210 are located outside the retaining slit 201. Therefore, even if centrifugal force is applied, the movement of the five engaging balls 216 is restricted. Accordingly, the inner hammer 166 cannot retract and does not produce an impact effect.

[0180] (3) Explanation of the vibrating part

[0181] The vibrating part 77 is disposed between the front plate portion 63 of the front gear housing 61 and the hammer housing 7. For example... Figure 10 , Figure 11 , Figure 25 As shown, the vibration unit 77 includes an anvil 8, a front cam 230, a rear cam 231, a limiting ring 232, a coil spring 233, and a vibration switching plate 234.

[0182] The front cam 230 is annular and integrally fixed to the anvil 8 within the front part of the hammer housing 7. A front cam surface 235 with continuous circumferential protrusions and recesses is formed on the rear surface of the front cam 230. The front cam 230 is supported in the hammer housing 7 by a bearing 236. A spring ring 237 is fixed to the front side of the front cam 230 and engaged in the anvil 8.

[0183] The rear cam 231 is mounted externally to the anvil 8 behind the front cam 230. Also... Figure 26 As shown in Figure A, the rear cam 231 is an annular shape with a diameter larger than that of the front cam 230. A rear cam surface 238 with continuous circumferential protrusions and concavities is formed on the front surface of the rear cam 231. Furthermore... Figure 26 As shown in Figure B, three cam claws 239, 239... are formed at equal circumferential intervals on the outer periphery of the rear surface of the rear cam 231. A plurality of balls 240, 240... are arranged circumferentially inside the cam claws 239 and behind the rear cam 231. Also as... Figure 26 As shown in Figure C, a receiving washer 241 is disposed behind the ball 240 and on the front side of the front plate portion 63, thereby supporting the ball 240. Three locking protrusions 242, 242... protrude radially outward from the outer periphery of the receiving washer 241. A locking rib 243 is provided protruding from the front surface of the front plate portion 63. The locking rib 243 engages with the locking protrusions 242 in the rotational direction, thereby restricting the rotation of the receiving washer 241.

[0184] The limiting ring 232 is configured such that its diameter is larger than that of the receiving washer 241 and it can move back and forth in front of the front plate portion 63. A guide rib 245, smaller in diameter than the limiting ring 232 and annular in shape, is provided protruding rearward on the rear surface of the hammer housing 7. Three limiting pins 246, 246… are provided on the outer side of the guide rib 245 and on the rear surface of the hammer housing 7. The limiting pins 246 are arranged at equal intervals in the circumferential direction and protrude rearward, such as… Figure 12 As shown in A, the rear end is inserted into the receiving hole 63a provided in the front plate portion 63. Cutout recesses 247 are formed on the inner side of each limiting pin 246 and on the guide rib 245 respectively.

[0185] Three engaging recesses 248, 248... are formed on the outer periphery of the limiting ring 232 for engaging with each limiting pin 246. This allows the limiting ring 232 to move back and forth along the limiting pin 246 while its rotation is restricted by the limiting pin 246. Three limiting protrusions 249, 249... are formed on the inner side of each engaging recess 248 and on the inner periphery of the limiting ring 232, protruding towards the center. Each limiting protrusion 249 protrudes into the inner side of the guide rib 245 via a notch 247. In the forward position of the limiting ring 232, each limiting protrusion 249 engages with each cam pawl 239 provided on the rear cam 231 in the rotational direction. This restricts the rotation of the rear cam 231. In the retracted position of the limiting ring 232, each limiting protrusion 249 separates from the rear of each cam pawl 239. This allows the rear cam 231 to rotate freely.

[0186] A washer 250 is provided on the rear side of the limiting ring 232. The diameter of the washer 250 is the same as that of the limiting ring 232, and it has through holes 251, 251... for each limiting pin 246 to pass through.

[0187] like Figure 12 As shown in Figure A, each disc spring 233 is disposed within the receiving hole 63a of the front plate portion 63, between the washer 250 and the bottom of the receiving hole 63a. Each disc spring 233 is externally mounted to the rear end of each limiting pin 246 that has penetrated through the washer 250. Accordingly, each disc spring 233 applies a forward force to the washer 250 and the limiting ring 232.

[0188] Three vibration switching plates 234 are arranged at equal intervals along the circumferential direction on the outer side of the limiting ring 232, at a different phase from that of the limiting pin 246. Each vibration switching plate 234 is a thin plate extending in the front-rear direction. A front folded portion 252 is formed on the front part of each vibration switching plate 234, which bends inward and locks into the front surface of the limiting ring 232. A rear folded portion 253 is formed on the rear part of each vibration switching plate 234, which bends outward. The outer ends of each rear folded portion 253 are formed into tapered portions 254 that bend backward and outward at both ends in the width direction.

[0189] Three retaining grooves 255, 255... are formed on the outer peripheral surface of the front plate portion 63 of the front gear housing 61. Each retaining groove 255 opens radially outward and forward. The vibration switching plate 234 engages with each retaining groove 255. However, each tapered portion 254 protrudes radially outward from the retaining groove 255.

[0190] Three support ribs 256, 256... are provided protruding inwards on the inner circumferential surface of the hammer housing 7. Each support rib 256 is inserted into a retaining groove 255 from the front, thereby supporting the vibration switching plate 234 between itself and the inner surface of the retaining groove 255. Accordingly, each vibration switching plate 234 can move back and forth between the retaining groove 255 and the support rib 256. However, each vibration switching plate 234 and the limiting ring 232 that is used to lock the front bending portion 252 are subjected to a forward force.

[0191] Regarding the vibration unit 77, the forward restriction and release of the vibration switching plates 234 are switched by rotating the mode switching ring 6, thereby allowing selection of whether vibration is present or absent. Specifically, when the forward restriction of the vibration switching plate 234 is released, as described above, the restriction ring 232 advances, and the restriction protrusion 249 engages with the cam pawl 239 of the rear cam 231. Accordingly, the rotation of the rear cam 231 is restricted. In this case, when the anvil 8 rotates, the front cam surface 235 of the front cam 230 engages with the rear cam surface 238 of the rear cam 231 in the rotational direction. Therefore, the anvil 8 vibrates by making slight movements in the front-rear direction relative to the gap with the main shaft 165.

[0192] When the forward movement of the vibration switching plate 234 is restricted, as described above, the restricting ring 232 retracts, and the restricting protrusion 249 separates rearward from the cam pawl 239. Accordingly, the rotation restriction of the rear cam 231 is released. In this case, even if the anvil 8 rotates, the front cam 230 will not engage with the rear cam 231, and therefore, the anvil 8 will not vibrate.

[0193] Here, the front cam 230 is directly supported by a bearing 236, and the forward movement of the rear cam 231 is restricted by the bearing 236. This reduces the number of parts and achieves compactness in the axial direction.

[0194] (4) Description of the linkage switching unit

[0195] like Figure 10 and Figure 23As shown, a rib 260 is formed circumferentially on the inner circumference of the mode switching ring 6 and on the outer side of the vibration switching plate 234. The rear bend 253 of the vibration switching plate 234, which is subjected to forward force, engages with the rib 260 from the rear. Three sharp, conical cutouts 261, 261... are formed at equal intervals circumferentially on the rib 260. The conical portion 254 of the rear bend 253 can engage with each cutout 261. Accordingly, at the rotational position of the mode switching ring 6 where each cutout 261 is in front of each conical portion 254, the limiting ring 232 and the vibration switching plate 234 are advanced to a forward position by the force applied by the coil spring 233. Accordingly, as described above, the limiting ring 232 limits the rotation of the rear cam 231. When the mode switching ring 6 is rotated, the conical cut-off portions 261 press the conical portions 254 backward, causing the vibration switching plate 234 and the limiting ring 232 to retract to a rearward position. As a result, the limiting ring 232 separates from the rear cam 231 to the rear, allowing the rear cam 231 to rotate freely.

[0196] like Figure 23 and Figure 27 As shown, a guide plate 265 is integrally formed at the rear end of the mode conversion ring 6. The guide plate 265 is formed in an arc shape along the circumference of the mode conversion ring 6 and extends rearward. A curved guide slit 266 is formed on the guide plate 265. The end of the guide slit 266 in the left-turning direction in the main view has a first slit 267 extending in the right-turning direction of the guide plate 265. A second slit 268 is continuously formed on the first slit 267 and tilts forward as it approaches the right-turning direction from the end of the first slit 267. A third slit 269 is continuously formed on the second slit 268 and extends in the right-turning direction from the end of the second slit 268. A fourth slit 270 is continuously formed on the third slit 269 and tilts forward as it approaches the right-turning direction from the end of the third slit 269. A fifth slit 271 is continuously formed on the fourth slit 270 and extends in the right-turning direction from the end of the fourth slit 270.

[0197] A plurality of protrusions 272, 272... are formed circumferentially on the inner side of the guide plate 265 and on the rear surface of the protrusion 260 of the mode conversion ring 6. The protrusions 272 are arranged at predetermined intervals circumferentially. Furthermore... Figure 12 As shown in C, a leaf spring 273 is held behind the protrusion 272 and on the lower surface of the front gear housing 61, elastically engaging with the protrusions 272 and 272. The engaging position of the leaf spring 273 becomes the switching position for each operating mode.

[0198] A thick-walled portion 274 is formed on the outer surface of the guide plate 265, excluding the guide slit 266. The outer surface of the thick-walled portion 274 protrudes radially outward more than the guide slit 266. The thick-walled portion 274 has a first triangular mountain-shaped portion 275 protruding rearward on the front side of the second slit 268 and the third slit 269. The thick-walled portion 274 has a second mountain-shaped portion 276 with a slope that moves rearward as it moves towards the right-turning direction from the front side of the fourth slit 270 and the fifth slit 271. The slope of the second mountain-shaped portion 276 extends rearward beyond the end of the fifth slit 271. A circumferentially shorter rear flat portion 277 and a front flat portion 278 are formed on the slope of the second mountain-shaped portion 276. The front flat portion 278 is located in front of the fifth slit 271.

[0199] A mode conversion lever 280, located on the lower side of the front gear housing 61, engages with a guide slit 266. The mode conversion lever 280 has a straight section 281 extending in the front-rear direction at its front end. The straight section 281 passes through a support frame 282 located on the lower surface of the front gear housing 60, thereby supporting the rod holder 310 (described later). The mode conversion lever 280 has a square frame section 283 extending in the vertical direction at the rear end of the straight section 281. An upward-facing guide protrusion 284 is formed on the upper surface of the rear end of the straight section 281. The guide protrusion 284 engages with the guide slit 266 from the outside, allowing relative movement within the guide slit 266.

[0200] A mode switching fork 285, located on the lower side of the front gear housing 61, passes through the square frame portion 283 of the mode switching lever 280. The mode switching fork 285 has a pair of left and right connecting rod portions 286, 286, and a connecting portion 287 connecting the connecting rod portions 286, 286. The connecting portion 287 passes through the square frame portion 283 of the mode switching lever 280 in a left-right direction. The connecting rod portions 286, 286 extend upwards and outwards from the left and right ends of the connecting portion 287. An elongated hole 288 extending along the elongation direction of each connecting rod portion 286 is formed in the middle portion of each connecting rod portion 286. Furthermore... Figure 18 As shown in C, a pair of support shafts 289, 289 are formed on the lower half of the front gear housing 61 and on the left and right circumferential surfaces facing outward. The support shafts 289, 289 are loosely inserted into the elongated holes 288, 288.

[0201] At the upper end of the connecting rod portions 286, 286, a pair of retaining pins 290, 290 are inserted radially outward from the front gear housing 61. A pair of guide holes 291, 291 extending in the front-rear direction are formed on the left and right sides of the front gear housing 61. The retaining pins 290, 290 pass through the guide holes 291, 291 and engage with the annular groove 215 of the hammer sleeve 168 inside the front gear housing 61.

[0202] Accordingly, when the mode switching ring 6 is rotated, the mode switching rod 280, which engages with the guide protrusion 284 and the guide slit 266, is guided by the guide slit 266 and moves back and forth. Consequently, the connecting portion 287 of the mode switching fork 285 moves back and forth, and therefore, the left and right connecting rod portions 286, 286 swing back and forth around the support shafts 289, 289. Consequently, the hammer sleeve 168, which is engaged by the upper locking pins 290, 290, moves linearly in the back-and-forth direction.

[0203] Here, the connecting rod 286 and the support shaft 289 are joined via the elongated hole 288. Therefore, even if the lower end of the connecting rod 286 swings back and forth, the support shaft 289 can move relative to it within the elongated hole 288, allowing the locking pin 290 to move linearly along the guide hole 291 in the front-back direction. This ensures that the hammer sleeve 168 always moves smoothly in a straight line without tilting due to the locking pins 290, 290 located on the left and right outer sides of the shaft. Furthermore, due to the clearance between the elongated hole 288 and the support shaft 289, even if the mode switching fork 285 is made of a relatively hard material, assembly can be performed without difficulty.

[0204] A linkage winding portion 295 is provided on the inner side of the guide plate 265. The linkage winding portion 295 is an arc-shaped plate body fixed to the guide plate 265 in an overlapping state from the inside. A guide window 296 is formed in the linkage winding portion 295 along the circumferential direction. A curved guide end 297 is formed at the rear end of the guide window 296. The guide end 297 has a first end 298 extending circumferentially along the linkage winding portion 295 at its end in the same left-turning direction as the guide plate 265. A second end 299 is continuously formed on the first end 298, which is inclined forward as it moves towards the right-turning direction from the end of the first end 298. A third end 300 is continuously formed on the second end 299, extending circumferentially from the end of the second end 299.

[0205] The linkage rod 301 is engaged with the linkage winding part 295. The linkage rod 301 is a strip groove 303 provided on the lower surface of the front gear housing 61 in the front-rear direction. Figure 18 C, Figure 23 The plate extends along the front-to-back direction. A latching pin 302 is provided at the front end, which engages with the guide end 297 of the linkage winding section 295 from the front. The rear part of the linkage rod 301 is positioned on the upper side of the speed switching retainer 153. The rear part of the linkage rod 301 bends downward between retaining plates 159. The rear part of the linkage rod 301 passes through the connecting plates 160 between the connecting plates 160 on the front side of the protrusion 148 of the speed switching wire 145. The lower end of the linkage rod 301 is formed into an inverted T-shape on the lower side of the speed switching retainer 153 to prevent detachment.

[0206] Accordingly, the linkage 301 can move back and forth when the locking pin 302 is engaged with the first end 298 of the guide end 297. When the linkage winding part 295 and the mode conversion ring 6 rotate to the left together in the main view, the linkage 301 slides forward due to the tilt of the second end 299. The rearward movement of the linkage 301 is restricted when the locking pin 302 is engaged with the third end 300.

[0207] A linkage cam 305 is provided on the upper rear side of the speed switching holding component 153. For example... Figure 12 B and Figure 14 As shown, the linkage cam 305 is a slender plate that narrows towards the front and has bevels on both sides. A groove 306 is formed at the rear of the linkage cam 305, extending from the rear end towards the center in the left-right direction. The eccentric pin 152 of the speed switching gear 151 passes through the groove 306 from above. A guide recess 307 is formed on the lower surface of the linkage cam 305 in the left-right direction. A guide protrusion 157 on the upper surface of the speed switching retainer 153 engages with the guide recess 307. Accordingly, the linkage cam 305 and the speed switching retainer 153 move back and forth integrally. Furthermore, the left-right movement of the linkage cam 305 and the eccentric pin 152 correspondingly slides left and right on the speed switching retainer 153.

[0208] Two parallel rods, left and right, extend through the left and right sides of the holding plates 159, 159 of the speed switching holding member 153. The rear ends of the left and right rods 308, 309, which have penetrated the holding plates 159, 159, are respectively opposed to the left and right inclined surfaces of the linkage cam 305. The front-to-back length of the right rod 309 is shorter than that of the left rod 308. The front parts of the left and right rods 308, 309 extend through the left and right sides of the rod holding member 310. The rod holding member 310 is supported within the support frame 282 of the front gear housing 61, allowing the straight portion 281 of the mode conversion rod 280 to pass through. A linkage rod 301 is supported on the upper surface of the rod holding member 310.

[0209] Accordingly, the left and right rods 308 and 309 are supported in parallel by the retaining plates 159 and 159 and the rod retainer 310, and can slide back and forth respectively. A spring ring 311 for preventing detachment and a coil spring 312 for cushioning are provided on the rear side of the rod retainer 310 and on the left and right rods 308 and 309. The front ends of the left and right rods 308 and 309, which penetrate the rod retainer 310, are opposite to the rear surface of the thick-walled portion 274 provided on the guide plate 265 of the mode conversion ring 6.

[0210] Regarding the linkage switching unit 78, as the mode switching ring 6 rotates, the front and rear positions of the hammer sleeve 168 are switched by means of the mode switching fork 285.

[0211] Furthermore, with the rotation of the mode switching ring 6, the linkage lever 301 switches between a state that allows the speed switching retainer 153 to move forward and backward and a state that restricts the speed switching retainer 153 to move backward while keeping it in the forward position.

[0212] Furthermore, with the rotation of the mode switching ring 6, the state is switched to a state in which the forward and backward movement of the left and right bars 308 and 309 is unrestricted between the linkage cam 305 and the thick-walled portion 274, which together with the speed switching retainer 153 are allowed to move forward and backward, and a state in which the forward and backward movement of the left and right bars 308 and 309 is restricted by the linkage cam 305 and the thick-walled portion 274, which together with the speed switching retainer 153 are always in the forward position.

[0213] These combinations allow for the mechanical selection of four motion modes. Each motion mode is further explained in detail below.

[0214] (5) Description of the cutter head assembly structure

[0215] For example Figure 28 and Figure 29 As shown, a blade insertion hole 315 with an open front end is formed at the axis of the anvil 8. The cross-section of the blade insertion hole 315 is a regular hexagon. A blade sleeve 316 is externally mounted to the front end of the anvil 8 in a manner that allows it to move back and forth. A pair of ball bearing storage portions 317, 317 are provided inside the blade sleeve 316 and on the anvil 8. The ball bearing storage portions 317 are elongated oval shapes extending in the front-back direction and are located at a point symmetrical about the blade insertion hole 315. The ball bearing storage portions 317 have a tapered shape whose cross-section decreases from the radially outer side to the radially inner side. A pair of balls 318, 318 are stored in the ball bearing storage portions 317, 317. The balls 318 are stored in the ball bearing storage portions 317 in a manner that allows them to move in both the radial and front-back directions. The diameter of the ball bearing 318 is larger than the radially inner opening of the ball bearing receiving portion 317, allowing it to protrude from the opening into the cutter insertion hole 315 at its radially inner position. Furthermore... Figure 25 As shown, an annular groove 319 is formed at the rear of the ball bearing receiving part 317 and in the anvil seat 8. Two O-rings 320, 320 are externally mounted in the groove 319.

[0216] An annular stop 321 is formed on the inner circumference of the cutter sleeve 316. When the stop 321 is located outside the balls 318, 318, it restricts the balls 318, 318 to a protruding position protruding from the openings of the ball receiving portions 317, 317. A conical spring 322, whose diameter increases towards the rear, is externally mounted on the front side of the stop 321 and on the anvil 8. The front end of the conical spring 322 abuts against a flat washer 324 positioned at the front end of the anvil 8 by means of an annular spring 323. The rear end of the conical spring 322 abuts against the stop 321. Accordingly, the conical spring 322 applies a rearward force to the cutter sleeve 316. A spring ring 237, locked in the anvil 8, is located behind the cutter sleeve 316. Accordingly, as... Figure 10 As shown, a force is applied to the cutter sleeve 316 to the retracted position where it abuts against the spring ring 237. In this retracted position, the stop portion 321 is located outside the balls 318, 318.

[0217] With the cutter sleeve 316 in the retracted position, insert the cutter head B into the cutter head insertion hole 315. Then, as... Figure 29 As shown in Figure A, the balls 318, 318 that abut against the cutter head B overcome the force exerted by the O-ring 320 and move behind the stop portion 321 within the ball receiving portions 317, 317. Thus, the balls 318, 318 move away from the rear of the ball receiving portions 317, 317. Therefore, even without the cutter head sleeve 316 sliding forward, the cutter head B can be directly inserted into the cutter head insertion hole 315. At this time, the ball receiving portions 317, 317 become tapered, expanding radially inward to radially outward. Therefore, the balls 318, 318 that abut against the cutter head B and move towards the rear of the ball receiving portions 317, 317 move along the tapered shape in a direction away from the cutter head insertion hole 315. Therefore, the load during cutter head insertion is reduced.

[0218] When the blade is fully inserted, as Figure 29 As shown in B, the O-ring 320 applies force to move the balls 318, 318 towards the inside of the stop portion 321. Accordingly, the balls 318, 318 return to the protruding position protruding from the ball receiving portions 317, 317 and are locked in place on the cutter head B, thereby preventing the cutter head B from falling off.

[0219] On the other hand, such as Figure 29 As shown in Figure C, if the force exerted by the conical spring 322 is overcome and the cutter sleeve 316 slides forward, the restriction on the movement of the balls 318 by the stop portion 321 is released. Accordingly, the cutter head B can be pulled out from the cutter head insertion hole 315. If the cutter head B is pulled out, the balls 318 return to their protruding positions from the ball receiving portions 317 and 318 due to the force exerted by the O-ring 320, thus becoming... Figure 29 The state of B.

[0220] Here, a conical spring 322 is used to apply force to the cutter head sleeve 316, so even if the free length of the conical spring 322 is increased, it is difficult to bend. This serves as a countermeasure against improper assembly or disassembly of the cutter head B. Furthermore, it increases the applied force. Therefore, it is less likely for the cutter head B to detach due to vibration.

[0221] (Explanation of each action mode)

[0222] Next, the switching and operation of each operating mode based on the linkage switching unit 78 will be explained. It should be noted that stop ribs 327 and 327 ( ) are provided protruding from the front of the front gear housing 61 and on the left and right sides. Figure 9 A, Figure 13 , Figure 23 The stop ribs 327 restrict the left and right rotational position of the guide plate 265 as the mode switching ring 6 rotates.

[0223] (1) Drilling mode

[0224] like Figure 19 As shown in A, the mode conversion ring 6 rotates to the extreme position to the right during the main view to form the drilling mode.

[0225] In drilling mode, the guide plate 265 is also in the right-turn position, and the first and second mountain-shaped portions 275 and 276 of the thick-walled portion 274 avoid the front of the left and right bars 308 and 309. Figure 19 (B, C).

[0226] Accordingly, the mode switching lever 280 is in a retracted position such that the guide protrusion 284 is located in the first slit 267 of the guide slit 266. Consequently, the connecting portion 287 of the mode switching fork 285 is in the retracted position, causing the left and right connecting rod portions 286, 286 to swing about the pivots 289, 289, and causing the upper locking pins 290, 290 to slide towards the front end of the guide holes 291, 291.

[0227] Accordingly, the hammer sleeve 168 is in the forward position, and therefore, as described above, the rear groove portion 211 and the middle groove portion 212 of the outer fitting groove 210 are located outside the retaining slit 201. Therefore, even when centrifugal force is applied, the movement of the five engaging balls 216 is restricted, and the retraction of the inner hammer 166 is also limited. Figure 19 (D, E).

[0228] The locking pin 302 of the linkage lever 301 is engaged with the first end 298 of the guide end 297 of the linkage winding part 295, thereby allowing forward movement. Accordingly, the speed switching retainer 153 can move back and forth, thereby also allowing the rotation of the speed switching gear 151, thus enabling the selection of gears 1-4 based on the speed switching dial 9.

[0229] On the other hand, the cut-off portion 261 provided on the protrusion 260 of the mode switching ring 6 is offset relative to the vibration switching plate 234 in the circumferential direction. Accordingly, the vibration switching plate 234 is in the retracted position. Figure 19 E).

[0230] In this drilling mode, after mounting the drill bit B onto the anvil 8, pressing the trigger 18 turns on the switch 17. Power is then supplied to the motor 4, causing the rotating shaft 53 to rotate together with the rotor 46.

[0231] Therefore, the input from the input gear 74 is reduced and transmitted to the spindle 165 at the speed selected in the reduction unit 75. The inner hammer 166, outer hammer 167, hammer sleeve 168, and spindle 165 rotate together, and the anvil 8 is rotated by means of the arms 172. Accordingly, the workpiece can be pierced or otherwise machined using the tool head B.

[0232] At this time, even if the torque on the cutter head B and the anvil 8 increases, the impact part 76 will not strike because the retraction of the inner hammer 166 is restricted. In addition, since the vibration switching plate 234 is in the retracted position, the anvil 8 will not vibrate due to the vibration part 77.

[0233] (2) Vibration drilling mode

[0234] like Figure 20 As shown in A, the mode conversion ring 6 is transformed into a vibratory drilling mode by turning left at a specified angle when viewed from the main view, starting from the drilling mode.

[0235] In vibratory drilling mode, the guide plate 265 is in a right-hand rotating position, and the first and second mountain-shaped portions 275 and 276 of the thick-walled portion 274 are in positions allowing the left and right bars 308 and 309 to move back and forth. The mode conversion lever 280 is in a retracted position because the guide protrusion 284 is located at the end of the first slit 267. Accordingly, the hammer sleeve 168 is in the forward position, thus restricting the retraction of the inner hammer 166. Figure 20 (B~D).

[0236] The locking pin 302 of the linkage lever 301 is engaged with the first end 298 of the guide end 297 of the linkage winding part 295, allowing forward movement in this state. Accordingly, the speed switching retainer 153 can move back and forth, and the speed switching gear 151 can also be rotated, thus enabling selection of speeds 1-4 based on the speed switching dial 9.

[0237] On the other hand, the cut-off portion 261 provided on the protrusion 260 of the mode switching ring 6 is located in front of the tapered portion 258 of the vibration switching plate 234. Accordingly, the vibration switching plate 234 advances, causing the limiting ring 232 to advance to the engagement position where it engages with the rear cam 231. Figure 20 E).

[0238] In this vibration drilling mode, after the drill bit B is mounted on the anvil 8, the trigger 18 is pressed to turn on the switch 17. Power is then supplied to the motor 4, causing the rotating shaft 53 to rotate together with the rotor 46.

[0239] Therefore, the input from the input gear 74 is reduced and transmitted to the spindle 165 at the speed selected in the reduction unit 75. The inner hammer 166, outer hammer 167, hammer sleeve 168, and spindle 165 rotate together, and the anvil 8 is rotated by means of the arms 172. Accordingly, the workpiece can be pierced or otherwise machined using the tool head B.

[0240] At this time, since the rotation of the rear cam 231 is restricted, when the cutter head B presses against the workpiece and causes the anvil 8 to retract, the rotating front cam 230 engages with the rear cam 231. Accordingly, vibration in the axial direction is generated in the anvil 8.

[0241] Furthermore, even if the torque on the blade B and the anvil 8 increases, the inner hammer 166 will not strike using the striking part 76 because the retraction of the inner hammer 166 is restricted.

[0242] (3) Impact on the large-scale model

[0243] like Figure 21 As shown in A, the mode conversion ring 6 starts from the vibration drilling mode and turns to the left at a specified angle in the main view to form the impact mode.

[0244] In the high-impact mode, the guide plate 265 also rotates to the left, causing the guide protrusion 284 of the mode switching lever 280 to move relative to the third slit 269 via the second slit 268. Accordingly, the mode switching lever 280 advances to the middle position. Then, the connecting portion 287 of the mode switching fork 285 advances, causing the left and right connecting rod portions 286, 286 to swing around the support shafts 289, 289. Accordingly, the upper locking pins 290, 290 retract towards the middle position of the guide holes 291, 291, causing the hammer sleeve 168 to slide towards the middle position. Figure 21 (B to E). In this intermediate position, as described above, the middle groove portion 212 of the outer fitting groove 210 is located outside the retaining slit 201.

[0245] Furthermore, the cut-off portion 261 provided on the protrusion 260 of the mode switching ring 6 is offset relative to the vibration switching plate 234 in the circumferential direction. Accordingly, the vibration switching plate 234 is in the retracted position. Figure 21 E).

[0246] On the other hand, the guide plate 265 causes the first mountain-shaped portion 275 of the thick-walled portion 274 to move forward of the left rod 308. Additionally, it causes the front flat portion 278 of the second mountain-shaped portion 276 to move forward of the right rod 309. Accordingly, the forward movement of the left and right rods 308 and 309 is restricted.

[0247] Furthermore, the linkage winding section 295 also rotates to the left, causing the locking pin 302 of the linkage rod 301 to move relative to the third end 300 from the first end 298 via the second end 299. Accordingly, the linkage rod 301 slides to the forward position, causing the speed switching holding member 153 and the linkage cam 305 to advance to the forward position.

[0248] At this time, the inclined edge of the linkage cam 305 abuts against the left bar 308, which restricts its forward movement, as it moves forward. Consequently, the linkage cam 305 slides to the right due to the guidance of the inclined edge, causing the speed switching gear 151 to rotate to the 3rd gear position via the eccentric pin 152. The right bar 309 does not interfere with the sliding of the linkage cam 305. Thus, the backward movement and leftward sliding of the linkage cam 305 are restricted, thereby limiting the rotation of the speed switching gear 151 and the speed switching dial 9. Therefore, the 3rd gear of the reduction gear 75 is fixed.

[0249] In this high-impact mode, after assembling the cutter head B onto the anvil 8, pressing the trigger 18 turns on the switch 17. Power is then supplied to the motor 4, causing the rotating shaft 53 and the rotor 46 to rotate together.

[0250] Therefore, the input from the input gear 74 is reduced in speed at the third gear in the reduction section 75 and transmitted to the main shaft 165. The inner hammer 166 rotates together with the outer hammer 167, the hammer sleeve 168, and the main shaft 165, and the anvil 8 is rotated by means of the arms 172. Accordingly, screw tightening and the like can be performed using the cutter head B. At this time, due to the generation of centrifugal force, the three outermost of the five engaging balls 216 move radially outward. Accordingly, as described above, the outer hammer 167 and the hammer sleeve 168 also rotate together with the inner hammer 166.

[0251] When the torque of the anvil 8 increases due to screw tightening, such as Figure 30 As shown, the inner hammer 166 causes the cam balls 183, 183 to rotate along the inner cam grooves 180, 180 of the main shaft 165, and retracts while rotating, overcoming the forces of the two outer and inner disc springs 169, 170. At this time, the two engaging balls 216 of the inner fitting groove 185 retract within the support groove 204 of the outer hammer 167. The three radially outer engaging balls 216 are configured to span the retaining slit 201 of the outer hammer 167 and the central groove 212 of the hammer sleeve 168. Accordingly, the outer hammer 167 and the hammer sleeve 168 rotate in accordance with the rotation of the inner hammer 166 along the inner cam groove 180.

[0252] Furthermore, when the claws 181, 181 separate from the arms 172, 172, the force applied by the outer and inner disc springs 169, 170 and the guidance of the inner cam grooves 180, 180 cause the inner hammer 166 to advance while rotating together with the outer hammer 167 and the hammer sleeve 168, causing the claws 181, 181 to re-engage with the arms 172, 172. This generates a rotational impact force (shock) on the anvil 8. Further tightening is achieved through the repetition of this process. Because the impact is generated by applying the mass of the outer hammer 167 and the hammer sleeve 168 to the inner hammer 166, the total inertial force increases (approximately 3.7 times that of the low-impact mode). Furthermore, since the rotation is limited to three gears, even with increased torque, it is difficult to cause disengagement.

[0253] Here, two outer and inner disc springs 169 and 170 with shorter free lengths are used with the same number of coils. This increases the elastic energy of the inner hammer 166 when it retracts to its limit. On the other hand, since the force exerted by the inner hammer 166 when it is in the forward position is reduced, the installation load can be reduced even with two outer and inner disc springs 169 and 170. Additionally, it facilitates the retraction of the inner hammer 166 (the timing of the inner hammer 166's claw 181 passing over the arm 172 of the anvil 8 is advanced).

[0254] (4) Impact small mode

[0255] like Figure 22 As shown in A, the mode transition ring 6 starts from the large impact mode and turns left at a specified angle during the main view to form the small impact mode.

[0256] In the low-impact mode, the guide plate 265 also rotates to the left, causing the guide protrusion 284 of the mode switching lever 280 to move relative to the fifth slit 271 via the fourth slit 270. Accordingly, the mode switching lever 280 advances to the forward position. Then, the connecting portion 287 of the mode switching fork 285 advances, causing the left and right connecting rod portions 286, 286 to swing about the support shafts 289, 289. Accordingly, the upper locking pins 290, 290 retract towards the retracted position of the guide holes 291, 291, causing the hammer sleeve 168 to slide towards the retracted position. Figure 22 (B~E).

[0257] Furthermore, the cut-off portion 261 provided on the protrusion 260 of the mode switching ring 6 is offset relative to the vibration switching plate 234 in the circumferential direction. Accordingly, the vibration switching plate 234 is in the retracted position. Figure 22 E).

[0258] On the other hand, the guide plate 265 causes the first mountain-shaped portion 275 of the thick-walled portion 274 to move to the left from the front of the left rod 308. Additionally, it causes the rear flat portion 277 of the second mountain-shaped portion 276 to move forward towards the right rod 309. Accordingly, the left rod 308 is allowed to advance, while the right rod 309 abuts against the inclined surface of the second mountain-shaped portion 276 and retracts.

[0259] Furthermore, the linkage winding section 295 also turns to the left; however, the position of the locking pin 302 of the linkage rod 301 remains at the third end 300. Accordingly, the linkage rod 301 and the speed switching holding member 153 remain in the forward position.

[0260] However, regarding the linkage cam 305, the right bar 309, which is pressed against the second mountain-shaped portion 276 and retracts, abuts against the inclined side. Accordingly, the linkage cam 305 slides to the left by the guide of the inclined side, causing the speed switching gear 151 to rotate to the 4th gear position by means of the eccentric pin 152. The left bar 308 abuts against the inclined side as the linkage cam 305 slides, thereby advancing between the first mountain-shaped portion 275 and the second mountain-shaped portion 276. In this way, the retraction and rightward sliding of the linkage cam 305 are restricted, thereby restricting the rotation of the speed switching gear 151 and the speed switching dial 9, thus fixing the 4th gear of the deceleration unit 75.

[0261] In this low-impact mode, after assembling the cutter head B onto the anvil 8, pressing the trigger 18 turns on the switch 17. Power is then supplied to the motor 4, causing the rotating shaft 53 to rotate together with the rotor 46.

[0262] Therefore, the input from the input gear 74 is reduced in speed at the fourth gear in the reduction section 75 and transmitted to the main shaft 165. The inner hammer 166 rotates together with the main shaft 165, and the anvil 8 is rotated by means of the arms 172. Accordingly, screw tightening and other functions can be performed using the cutter head B.

[0263] In the retracted position of the hammer sleeve 168, as described above, the deepest front groove 213 of the outer fitting groove 210 is located outside the retaining slit 201 of the outer hammer 167. Accordingly, due to centrifugal force, all five engaging balls 216 move radially outward. Therefore, regarding the inner hammer 166, the inner two engaging balls 216 separate radially outward from the inner fitting groove 185. Accordingly, only the inner hammer 166 rotates integrally with the main shaft 165.

[0264] When the torque of the anvil 8 increases due to screw tightening, the inner hammer 166 causes the cam balls 183 to rotate along the inner cam grooves 180 and 180 of the main shaft 165, and rotates backward while overcoming the force of the two outer and inner disc springs 169 and 170. Furthermore, when the pawls 181 and 181 disengage from the arms 172 and 172, the inner hammer 166 rotates forward while advancing due to the force of the outer and inner disc springs 169 and 170 and the guidance of the inner cam grooves 180 and 180, thereby causing the pawls 181 and 181 to re-engage with the arms 172 and 172. This generates a rotational impact force (shock) on the anvil 8. Further tightening can be achieved through the repetition of this process. The impact at this time is generated only by the inner hammer 166 at speed 4; therefore, even at high speed, the torque is relatively low. This helps to prevent disengagement and over-tightening.

[0265] (5) Screwdriver (clutch) mode

[0266] By operating the display unit 27 in drilling mode or vibratory drilling mode, the screwdriver mode can be selected.

[0267] In screwdriver mode, the controller 25 monitors the output torque (motor current, speed) of the motor 4. When the output torque exceeds a specified value, the controller 25 stops the rotation of the motor 4. The specified value of the output torque can be changed by selecting a level on the display unit 27.

[0268] In screwdriver mode, the speed reduction unit 75 can select from 1st to 4th gear based on the speed switching dial 9.

[0269] On the other hand, in each operating mode, the fan 35 rotates together with the rotating shaft 53. External air is then drawn in through the air inlet 16 and passed through the main body 12 to cool the motor 4. The air is then directed radially outward from the fan 35 and discharged to the outside through the exhaust port 33. As described above, regarding the two upper exhaust ports 33A, 33A, air is guided upward by the inner edge and discharged upwards. Therefore, it is difficult for foreign objects to enter the exhaust ports 33A, 33A from above.

[0270] Furthermore, when switch 17 is turned on, lamp 21 illuminates the area in front of blade B. This allows for unimpeded operation even in dark environments. Additionally, lamp 21 can be switched on / off at will via touch operation on display unit 27.

[0271] (The effect of the invention that makes the motion mode correspond to the gear level)

[0272] The impact screwdriver 1 described above includes: a motor 4; a reduction gear 75 that reduces the rotation generated by the motor 4; and a striking part 76 and a vibrating part 77 (multiple working parts) that can operate by means of the reduced rotation by the reduction gear 75. The impact screwdriver 1 has a linkage switching part 78 (switching part) that selects the striking part 76 and the vibrating part 77 and operates them in drilling mode, vibratory drilling mode, high impact mode, and low impact mode (prescribed operating modes). The reduction gear 75 can select four speed levels.

[0273] Furthermore, the selection of the linkage switching unit 78 and the striking unit 76 (a specific working unit) respectively causes the deceleration unit 75 to perform a linkage operation, and causes the deceleration unit 75 to operate in the 3rd and 4th gears (prescribed gear shifting levels) corresponding to the large impact mode and small impact mode of the striking unit 76, respectively.

[0274] According to this structure, even with a reduction section 75 that can achieve four levels of speed change, it is possible to appropriately correspond to various operating modes and speed change levels, such as drilling mode, vibration drilling mode, large impact mode, and small impact mode.

[0275] The reduction gear 75 offers four selectable speed levels. This expands the range of options even for mechanical reduction gears 75, improving ease of use. Furthermore, it allows selection of speed levels suitable for various operating modes.

[0276] The working part includes a striking part 76 that strikes the anvil 8 in the direction of rotation, and the working part of the variable speed stage is configured to have a striking part 76 with a high impact mode and a low impact mode. Accordingly, it can be used with a variable speed stage that corresponds to the striking force.

[0277] The impact mode can be switched between a high-impact mode with a greater impact force on the anvil 8 and a low-impact mode with an impact force greater than the high-impact mode. Furthermore, the linkage switching unit 78 engages the deceleration unit 75 in a manner that makes the speed of the low-impact mode's gear shift (here, 4th gear) higher than the high-impact mode's gear shift (here, 3rd gear). Therefore, even if there are two impact modes, the appropriate gear shift can be used. In the high-impact mode, disengagement is reduced and an increase in torque is expected; in the low-impact mode, operating speed is increased, and screw breakage or over-tightening is reduced.

[0278] The linkage switching unit 78 can switch to a drilling mode that does not use the striking unit 76 to strike the anvil 8. In drilling mode, a 4-stage speed reduction stage based on the deceleration unit 75 can be selected. This improves the ease of use in drilling mode.

[0279] The working part includes a vibration unit 77 that causes the anvil 8 to vibrate in the axial direction. Furthermore, the linkage switching unit 78 can switch to a vibration drilling mode where the anvil 8 is vibrated by the vibration unit 77 instead of being struck by the striking unit 76. In the vibration drilling mode, a four-stage speed reduction system based on the deceleration unit 75 can be selected. This improves usability in the vibration drilling mode.

[0280] The reduction unit 75 has a speed switching holding member 153 and a linkage cam 305 (position changing member) that change position for each gear level, and a linkage switching unit 78 has a mode switching ring 6 (mode switching member) for selecting the working part. Furthermore, between the speed switching holding member 153 and the linkage cam 305 and the mode switching ring 6, there are a guide plate 265, a linkage winding part 295, a linkage rod 301, a left rod 308, and a right rod 309 (linkage members) that, in response to the operation of the mode switching ring 6, force the speed switching holding member 153 and the linkage cam 305 to move to a predetermined gear level (here, 3rd and 4th gears).

[0281] Accordingly, the appropriate speed level for the operating mode is automatically selected in response to the operation of the mode switching ring 6.

[0282] The mode switching ring 6 allows selection between the striking part 76 and the vibrating part 77 via rotation. Therefore, the operating mode can be easily switched using the mode switching ring 6.

[0283] The reduction unit 75 is housed in a cylindrical rear gear housing 60 (housing), and has, in the axial direction, three-stage internal gears 81A-81C, planetary gears 80A-80C revolving within the internal gears 81A-81C, and a rear gear carrier 85 and a front gear carrier 130 supporting the planetary gears 80A-80C. This allows for a reduction unit that facilitates easy setting of the gear shift stages.

[0284] The reduction unit 75 is configured to allow two internal gears 81A and 81B, which are adjacent in the axial direction and have different reduction ratios, to rotate independently. Furthermore, the reduction unit 75 is provided with a speed switching plate 110 (locking member) that can selectively engage with either of the internal gears 81A and 81B to restrict their rotation. Additionally, another internal gear 81C is configured to rotate and is configured to slide in the axial direction to a retracted position (first sliding position) where its rotation is restricted within the rear gear housing 60, causing the planetary gear 80C to revolve, and to a forward position (second sliding position) where it is not restricted in its rotation within the rear gear housing 60 and simultaneously engages with the planetary gear 80C and the front gear carrier 130. By combining the restriction of rotation of one of the two internal gears 81A and 81B by the speed switching plate 110 with the sliding position of the internal gear 81C, four gear shifting stages can be selected.

[0285] Therefore, even the mechanical reduction unit 75 can achieve 4-speed transmission.

[0286] The speed switching plate 110 is configured such that its middle portion is supported and its two ends are capable of swinging. The speed switching plate 110 can be switched to a backward tilting posture (first swinging posture) where one end is engaged with the outer circumference of one internal gear 81A and the other end is not engaged with the outer circumference of another internal gear 81B, and a forward tilting posture (second swinging posture) where one end is not engaged with the outer circumference of internal gear 81A and the other end is engaged with the outer circumference of internal gear 81B. Accordingly, the rotational restriction and release of the two internal gears 81A and 81B can be easily performed by swinging one speed switching plate 110.

[0287] A speed switching ring 114 (annular member) is rotatably provided on the outer side of the speed switching plate 110 of the rear gear housing 60. The speed switching ring 114 has alternately arranged rear pressing portions 115 (first pressing portions) that press one end of the speed switching plate 110 to switch it to a rearward tilting position, and front pressing portions 116 (second pressing portions) that press the other end to switch it to a forward tilting position. Furthermore, by rotating the speed switching dial 9 (rotation operation member) provided in the rear gear housing 60, the speed switching ring 114 can be rotated to achieve selective rotation restriction of the internal gears 81A and 81B.

[0288] Accordingly, the posture of the speed switching plate 110 can be switched easily using the speed switching ring 114 and the speed switching dial 9, saving space.

[0289] The speed switching ring 114 has multiple teeth 121 arranged circumferentially, and the speed switching dial 9 has an upper gear 126 (gear) that meshes with the teeth 121. The speed switching ring 114 can be rotated by the rotation operation of the speed switching dial 9.

[0290] Accordingly, the posture of the speed switching plate 110 can be switched by rotating the speed switching dial 9.

[0291] The impact screwdriver 1 described above includes: a motor 4; a reduction gear 75 driven by the motor 4 and capable of selecting a predetermined speed range; an inner hammer 166 (hammer) that performs striking work using the reduction gear 75; and a linkage switching unit 78 (switching unit) capable of switching between the speed range of the reduction gear 75 and whether the inner hammer 166 can perform striking work. Furthermore, when the inner hammer 166 can perform striking work, the linkage switching unit 78 restricts the selection of the speed range of the reduction gear 75; when the inner hammer 166 cannot perform striking work, the linkage switching unit 78 can select the speed range of the reduction gear 75.

[0292] The impact screwdriver 1 described above includes: a motor 4; and a reduction gear 75, which is driven by the motor 4 and can select a predetermined speed level, and can be driven in various operating modes, including drilling mode, vibratory drilling mode, screwdriver mode, and impact mode. Furthermore, the impact screwdriver 1 allows selection of the speed level of the reduction gear 75 in drilling mode, vibratory drilling mode, and screwdriver mode, but restricts the selection of the speed level of the reduction gear 75 in impact mode (high impact mode and low impact mode).

[0293] Therefore, in impact modes (large impact mode and small impact mode), it can always be used with the appropriate speed gear.

[0294] Regarding the invention that makes the operating mode correspond to the gear shift, the following modifications can be made.

[0295] The speed reduction section is not limited to 4 speeds; it can also have 3, 5, or more speeds.

[0296] In the above scheme, the gear shifter is matched with 3rd gear in the high-impact mode and with 4th gear in the low-impact mode, but it is not limited to this. For example, the same gear shifter can be set for both modes.

[0297] The impact mode is not limited to just two types: large impact mode and small impact mode. A single impact mode can be selected if the striking part has only one hammer. Alternatively, three types can be used: large impact mode, small impact mode, and medium impact mode.

[0298] Action modes other than impact mode are not limited to the above schemes. It may also not have any one or two of the drilling mode, vibratory drilling mode and screwdriver mode.

[0299] In the above scheme, only the impact mode corresponds to the specified gear level. However, it is possible to make the motion modes other than the impact mode also correspond to the specified gear level.

[0300] This invention can be used even with impact tools that only offer multiple impact modes. It can also be used with power tools that do not have impact modes.

[0301] The shapes of the speed switching retainer and the linkage cam are not limited to the above-described designs. Components other than the speed switching retainer and linkage cam can also be used as position changing parts.

[0302] The linkage components are not limited to the above-mentioned solutions and can be modified appropriately. For example, the linkage rod and the speed switching holding component can be formed as a single unit.

[0303] The position changing component and linkage component can be located on either the left or right side of the working unit, rather than on the bottom side. They can also be located inside the housing.

[0304] The motor is not limited to a brushless motor. It can also be an AC tool that does not utilize a battery pack.

[0305] While the above embodiments illustrate four mechanical impact screwdriver modes, the present invention is not limited to these impact screwdrivers. For example, the present invention can also be applied to impact screwdrivers that use a mechanical clutch to achieve the screwdriver mode instead of an electronic clutch, impact tools such as angular impact screwdrivers, and power tools such as screwdriver drills.

[0306] (The effect of the invention of two internal gears and a locking component)

[0307] The impact screwdriver 1 described above includes: a motor 4; a reduction gear 75 that reduces the rotation generated by the motor 4; and a striking part 76 and a vibration part 77, which operate by utilizing the rotation reduced by the reduction gear 75. Furthermore, the reduction gear 75 has, in the axial direction, three-stage internal gears 81A-81C, planetary gears 80A-80C revolving within the internal gears 81A-81C, and a rear gear carrier 85 and a front gear carrier 130 supporting the planetary gears 80A-80C.

[0308] The reduction unit 75 includes: a rotatable internal gear 81A (front-side internal gear) located at the front end; and a rotatable internal gear 81B (rear-side internal gear) located at the rear end of the internal gear 81A and having a different reduction ratio than the internal gear 81A. Furthermore, the reduction unit 75 includes a speed switching plate 110 (locking member), which is disposed radially outside the internal gears 81A and 81B, and can be switched to a rearward tilting position (first position) where the internal gear 81A is locked and its rotation is restricted, and a forward tilting position (second position) where the internal gear 81B is locked and its rotation is restricted. The reduction unit 75 also includes a speed switching ring 114 and a speed switching dial 9 (operation unit) capable of selectively switching the speed switching plate 110 to either the rearward or forward tilting position.

[0309] According to this structure, a speed reduction unit 75 that is compact in the axial direction and can smoothly and stably switch speeds can be obtained.

[0310] The speed switching plate 110 is configured such that the middle part is supported while the two ends are able to swing. In the backward tilting position, one end is locked to the outer circumference of the internal gear 81A, and in the forward tilting position, the other end is locked to the outer circumference of the internal gear 81B. Accordingly, the rotation restriction and release of the two internal gears 81A and 81B can be reasonably performed using one speed switching plate 110, saving space.

[0311] The reduction gear 75 is housed in the cylindrical rear gear housing 60, and the operating part includes a speed switching ring 114 and a speed switching dial 9. This allows for space-saving and easy switching of the posture of the speed switching plate 110 using the speed switching ring 114. Specifically, the speed switching ring 114 has a plurality of teeth 121 continuously formed circumferentially, and the speed switching dial 9 has an upper gear 126 integrally formed therein. Therefore, the speed switching ring 114 can be easily rotated by rotating the speed switching dial 9.

[0312] A planar gear ring 120 (gear ring) with teeth 121 is integrally provided on the speed switching ring 114. Accordingly, the teeth 121 can be easily provided on the speed switching ring 114.

[0313] The speed switching ring 114 is a frame-like body in which the rear pressing part 115 and the front pressing part 116 protrude differently in the axial direction and extend meanderingly in the circumferential direction. Accordingly, the structure of the speed switching ring 114 becomes simple.

[0314] Multiple speed switching plates 110 are provided. Accordingly, the rotation of internal gears 81A and 81B can be reliably limited.

[0315] The speed switching plate 110 is positioned at a point symmetrical about the axis of the internal gears 81A and 81B. Accordingly, the rotation of the internal gears 81A and 81B can be restricted to prevent them from tilting relative to the axis.

[0316] On the outer periphery of the internal gears 81A and 81B, a plurality of rear locking ribs 91 and front locking ribs 95 (locking ribs) extending along the axial direction are provided at predetermined intervals along the circumference of the internal gears 81A and 81B. In addition, rear locking portions 112 and front locking portions 113 are formed at both ends of the speed switching plate 110, which engage with the rear locking ribs 91 and front locking ribs 95 in the circumferential direction. Accordingly, the rotation restriction and release of the internal gears 81A and 81B can be reliably performed.

[0317] The rear locking portion 112 and the front locking portion 113 are formed in a curled shape. Accordingly, they can easily lock with the rear locking rib 91 and the front locking rib 95.

[0318] Internal gears 81A and 81B are arranged adjacent to each other in the axial direction, with an O-ring 93 (sealing member) sandwiched between their opposing surfaces. Furthermore, a rear flange 90 and a front flange 94 extending towards the center are formed at the opposite ends of the opposing surfaces of the internal gears 81A and 81B, respectively. Accordingly, a retaining space S is formed between the internal gears 81A and 81B, preventing grease from overflowing outwards from the radially inner side of the internal gears 81A and 81B, thereby preventing the grease from drying out.

[0319] The impact screwdriver 1 of the above scheme has: a motor 4; a rear gear carrier 85 driven to rotate by the motor 4; a pin 86 held in the rear gear carrier 85; a planetary gear 80A (first planetary gear) held in the pin 86 and having a first number of teeth; a planetary gear 80B (second planetary gear) held in the pin 86 and having a second number of teeth different from the first number of teeth; an internal gear 81A (first internal gear) meshing with the planetary gear 80A; an internal gear 81B (second internal gear) meshing with the planetary gear 80B; and a speed switching plate 110 (fixed component) that prevents either the internal gears 81A or 81B from rotating.

[0320] According to this structure, the two internal gears 81A and 81B can be selectively prevented from rotating by using a speed switching plate 110. Accordingly, a reduction unit 75 that is compact in the axial direction and can perform smooth and stable speed switching can be obtained.

[0321] The invention of the two internal gears and the locking component can be modified as follows.

[0322] The two internal gears on the front and rear sides of the speed switching plate (locking component) that restrict rotation are not limited to the first and second stages described above. For example, the locking component can also be used to restrict rotation of the internal gears in the second and third stages. The speed reduction stage is not limited to four stages. Multiple sets of locking components and two internal gears can be configured.

[0323] The number of locking components is not limited to two. For example, more than three can be arranged circumferentially on the internal gear to restrict rotation.

[0324] The shape of the locking component is not limited to the speed switching plate described above. The front and rear locking portions do not have to be curled. For example, the front and rear locking portions can be formed by simply bending the ends. The front and rear locking portions can also be formed by installing separate components. For example, the locking component can be formed by an elastic body and the front and rear locking portions can be formed by a pin component.

[0325] The support for the middle portion of the locking component is not limited to the structure of the speed switching retainer based on the above-described scheme. The locking component can be supported by directly providing a spacer wall within the housing. Alternatively, a pin component can be used to support the middle portion of the locking component.

[0326] The annular component is not limited to the speed switching ring described above. The annular component can be a strip-like structure, rather than a frame-like structure extending circumferentially. Accordingly, for the teeth, instead of a separate gear ring, the teeth can be formed directly within the annular component.

[0327] Multiple sealing components can be provided between the two internal gears related to the gear change. Sealing components other than O-rings can also be used.

[0328] It is also possible to achieve a seal between the opposing surfaces of the two internal gears without using a sealing component. For example, an annular protrusion can be formed on one of the opposing surfaces, and an annular groove can be formed on the other opposing surface, with the protrusion inserted into the groove, thereby achieving a seal.

[0329] The two internal gears related to the gear change may not be adjacent in the axial direction. In this case, the sealing component between the opposing surfaces of the internal gears can be omitted. The flange can also be omitted.

[0330] The motor is not limited to a brushless motor. It can be used for AC tools that do not use a battery pack.

[0331] Although the above scheme illustrates four types of mechanical impact screwdrivers, the present invention is not limited to impact screwdrivers. It can also be applied to other impact tools, screwdrivers, screwdrivers, and other power tools as long as they have a reduction gear with planetary gears and internal gears.

[0332] (The effect of the invention of the rod component)

[0333] The impact screwdriver 1 described above includes: a mode conversion ring 6 (operating component); a connecting rod portion 286 (rod component) of a mode conversion fork 285, which swings via a support shaft 289 as the mode conversion ring 6 is operated; and a hammer sleeve 168 (switching component), which moves linearly in conjunction with the swinging of the connecting rod portion 286. Furthermore, inserting the support shaft 289 into the connecting rod portion 286 allows the connecting rod portion 286 to swing; the insertion portion of the support shaft 289 in the connecting rod portion 286 is an elongated hole 288 (elongated hole) extending along the connecting rod portion 286.

[0334] According to this structure, even if the connecting rod 286 swings around the support shaft 289, the axis of the hammer sleeve 168 and the movement trajectory of the end of the connecting rod 286 remain parallel. Therefore, even if the stroke of the hammer sleeve 168 increases, the possibility of the connecting rod 286 detaching from the hammer sleeve 168 or causing poor switching of operating modes is reduced. That is, smooth switching of operating modes is possible. Furthermore, the assemblability of the connecting rod 286 is also improved.

[0335] The hammer sleeve 168 is disposed inside the front gear housing 61, while the mode conversion ring 6 and connecting rod portion 286 are disposed outside the front gear housing 61, and the support shaft 289 protrudes from the outer surface of the front gear housing 61. Therefore, even when passing over the front gear housing 61, the hammer sleeve 168 can move smoothly in a straight line. The mode conversion fork 285 can also be easily assembled outside the front gear housing 61.

[0336] The linkage between the connecting rod 286 and the hammer sleeve 168 is achieved by engaging the locking pin 290 provided at the end of the connecting rod 286 with the hammer sleeve 168. Accordingly, the oscillation of the connecting rod 286 can be converted into the linear movement of the hammer sleeve 168.

[0337] The locking pin 290 is engaged with the hammer sleeve 168 via a linear guide hole 291 provided in the front gear housing 61, along the linear movement direction of the hammer sleeve 168. Accordingly, the movement of the locking pin 290 along the axial direction of the hammer sleeve 168 can be guided.

[0338] A striking part 76, including a main shaft 165 and an inner hammer 166 (hammer) externally mounted on the main shaft 165, is provided inside the front gear housing 61. The switching component is a hammer sleeve 168 (sleeve component) externally mounted on the inner hammer 166 and movable in the axial direction. Accordingly, the impact mode of the striking part 76 can be switched smoothly.

[0339] An annular groove 215 is formed on the outer periphery of the hammer sleeve 168, and a retaining pin 290 is engaged in the annular groove 215. This allows the hammer sleeve 168 to move smoothly in a straight line.

[0340] A pair of connecting rods 286 are provided, with one end connected to each other by a connecting part 287. The connecting part 287 swings with the operation of the mode switching ring 6, and the locking pins 290 provided at the other end of each connecting rod 286 are respectively locked into the ring grooves 215. Accordingly, the hammer sleeve 168 can reliably move linearly.

[0341] The locking pin 290 is positioned at a point symmetrical about the axis of the hammer sleeve 168. Therefore, the hammer sleeve 168 is unlikely to tilt.

[0342] The purpose of setting up mode switching ring 6 is to switch action modes. Accordingly, the linear movement of hammer sleeve 168 can be performed in conjunction with the switching of action modes.

[0343] The mode switching ring 6 is rotated to switch the action mode. This allows for easy switching of action modes.

[0344] The impact screwdriver 1 described above includes: a motor 4; an anvil 8 driven to rotate by the motor 4; an inner hammer 166 that strikes the anvil 8 along the direction of rotation; and a hammer sleeve 168 for switching operating modes, which is externally mounted on the inner hammer 166. Additionally, the impact screwdriver 1 includes: an annular groove 215 disposed on the outer periphery of the hammer sleeve 168; a locking pin 290 (locking portion) that locks into the annular groove 215; and a connecting rod portion 286 that allows the locking pin 290 to move only in the axial direction of the hammer sleeve 168.

[0345] In this structure, the possibility of the connecting rod 286 detaching from the hammer sleeve 168 or causing switching problems during operation mode switching is reduced. Therefore, smooth switching of operation modes is possible. Furthermore, the assemblability of the connecting rod 286 is also improved.

[0346] The following modifications can be made to the invention of the rod component.

[0347] The elongated hole provided in the connecting rod is not limited to an oblong hole; it can also be an elliptical hole or a square hole.

[0348] The locking pin can be integrally set on the connecting rod.

[0349] The two linkages can swing left and right separately without being connected by a connecting part.

[0350] The connecting rod can be located inside the housing.

[0351] The lever component can be used to switch between operating modes other than the impact mode. Accordingly, the switching component can be, for example, an internal gear for speed change provided in the reduction section.

[0352] In the above scheme, a support shaft is provided in the gear housing and an elongated hole is provided in the connecting rod. However, it is also possible to do the opposite. That is, even if a support shaft is provided in the connecting rod and an elongated hole is provided in the gear housing, the switching components such as the hammer sleeve and the internal gear can move only in the axial direction.

[0353] The motor is not limited to a brushless motor. It can be used for AC tools that do not use a battery pack.

[0354] This invention can also be applied to other power tools besides impact screwdrivers.

[0355] This invention is not limited to power tools; it can also be applied to work tools that are powered by air or an engine.

[0356] (The effect of the invention of overlapping planetary gears)

[0357] The impact screwdriver 1 described above includes: a motor 4; a reduction gear 75 that reduces the rotational speed generated by the motor 4; and a striking part 76 and a vibrating part 77, which operate by means of the rotational speed reduced by the reduction gear 75. Furthermore, the reduction gear 75 has, in the axial direction, internal gears 81A-81C forming a three-stage system, multiple planetary gears 80A-80C revolving within the internal gears 81A-81C, and a rear gear carrier 85 and a front gear carrier 130 that support each planetary gear 80A-80C respectively by means of pins 86 and 131. Moreover, each adjacent front planetary gear 80A and each adjacent rear planetary gear 80B in the axial direction is supported by a pin 86 in a radially overlapping manner.

[0358] According to this structure, a speed reduction section 75 that is compact and has high durability in the axial direction can be obtained.

[0359] The planetary gear 80A at the front end has a gear portion 83 adjacent to the planetary gear 80B at the rear end, and a bearing portion 84 extending towards the inner diameter side of the planetary gear 80B. The planetary gear 80B is externally mounted on the bearing portion 84 and overlaps with it. This allows the planetary gears 80A and 80B to overlap compactly with each other. Furthermore, since the planetary gear 80B does not contact the pin 86, mechanical losses caused by frictional resistance when using the planetary gear 80B can be reduced.

[0360] A bearing 87 is provided between the bearing section 84 and the pin 86. Accordingly, the two planetary gears 80A and 80B can be supported by one bearing 87.

[0361] Bearing 87 is a needle roller bearing. This makes it more compact radially. Furthermore, it ensures necessary lubrication even if the grease dries out.

[0362] The front internal gear 81A and the rear internal gear 81B are configured to rotate independently. Furthermore, a speed switching plate 110, a speed switching ring 114, and a speed switching dial 9 (rotation limiting part) are provided to selectively limit the rotation of the internal gears 81A and 81B. Therefore, two speed levels can be easily achieved by switching the rotation limits of the two internal gears 81A and 81B.

[0363] The following modifications can be made to the invention where planetary gears overlap.

[0364] Overlapping planetary gears are not limited to the first and second stages. For example, the second and third stage planetary gears can overlap each other. The number of stages in the reduction section is also not limited to four.

[0365] In the above scheme, the planetary gear in the front section is provided with a bearing portion, and the planetary gear in the rear section is externally mounted on the bearing portion. However, it can be the opposite. That is, the planetary gear in the rear section can be supported by a pin to form a bearing portion extending towards the front section, and the planetary gear in the front section can be externally mounted on the bearing portion.

[0366] The bearing between the bearing section and the pin can be a bearing other than a needle roller bearing. Alternatively, there may be no bearing at all.

[0367] In the above-described scheme, the second-stage planetary gear is externally mounted on and overlaps with the bearing portion where the first-stage planetary gear is located. However, it is also possible to externally mount the third-stage and subsequent planetary gears on the bearing portion. That is, the present invention also includes a scheme in which planetary gears of three or more stages overlap.

[0368] The motor is not limited to a brushless motor. It can be used for AC tools that do not use a battery pack.

[0369] Although the above scheme illustrates four types of mechanical impact screwdrivers, the present invention is not limited to impact screwdrivers. It can also be applied to other impact tools, screwdrivers, screwdrivers, and other power tools as long as they have a reduction gear with planetary gears and internal gears.

[0370] (Instructions for nail-driving blades)

[0371] In vibratory drilling mode, nails can be driven in using a nail-driving tool. For example... Figure 31 As shown, the nail-driving head B1 has a rotating shaft 330, a head 331, multiple balls 332, 332..., a washer 333, and a rubber sleeve 334.

[0372] The pivot portion 330 is inserted into the cutter head insertion hole 315 in the same manner as a normal cutter head B. However, the cross-sectional shape of the pivot portion 330 is circular rather than hexagonal. Accordingly, the pivot portion 330 is kept able to rotate within the cutter head insertion hole 315. A neck 335 is formed at the rear end of the pivot portion 330. When inserted into the cutter head insertion hole 315, the balls 318 of the ball receiving portions 317, 317 engage with the neck 335.

[0373] The head 331 and the pivot 330 are integrally formed. The head 331 is a large-diameter circle, and its front end face is flat except for the outer periphery. An annular locking groove 336 is formed on the outer periphery of the front side of the head 331. An annular recess 337 is formed on the rear surface of the head 331 and at the root of the pivot 330. Ball bearings 332, 332... are fitted into the annular recess 337.

[0374] Washer 333 is penetrated by pivot 330 behind head 331, and receives balls 332, 332...

[0375] A rubber sleeve 334 is externally mounted across the head 331 and the washer 333. The front and rear ends of the rubber sleeve 334 are respectively formed with annular front reduced diameter portions 338 and rear reduced diameter portions 339 that fold back towards the center. The front reduced diameter portion 338 engages with a locking groove 336 in the head 331. The rear reduced diameter portion 339 engages with the rear end of the washer 333. Accordingly, the washer 333 is connected to the head 331 in a state of contact with the ball 332.

[0376] The nail-driving head B1, like the nail-driving head B, has its pivot portion 330 inserted into the nail-driving head insertion hole 315. This causes the balls 318 of the ball-receiving portions 317 and 317 to engage with the constricted neck 335, preventing them from slipping out. Simultaneously, the washer 333 abuts against the front end face of the anvil 8. In this state, the rear end of the head 331 is not in contact with the washer 333.

[0377] When driving a nail, the front end face of the head 331 abuts against the head of the nail, and the impact screwdriver 1 operates in a vibratory drilling mode. The vibration generated in the anvil 8 in the front-to-back direction is then transmitted to the nail via the head 331. Therefore, when the impact screwdriver 1 is pressed in, the nail can be driven into the workpiece. Even if the washer 333 rotates with the anvil 8, the ball bearings 332, 332... between the head 331 and the washer 333 interrupt the transmission of rotation, so the head 331 will not rotate.

[0378] The nailing head B1 can also be fitted to impact screwdrivers other than the four types of mechanical impact screwdrivers described above, as well as power tools (power tools with a vibration mode and a hexagonal hole in the final output shaft for attaching and detaching the head).

Claims

1. An electric tool, comprising: motor; A speed reduction unit that reduces the rotational speed generated by the motor; as well as The working part operates by means of rotation reduced in speed by the reduction unit. The reduction unit has, in the axial direction, at least two-stage internal gears, planetary gears revolving within the internal gears, and a gear carrier supporting the planetary gears. The power tool is characterized in that... The deceleration unit has: A rotatable front-side internal gear, wherein the front-side internal gear is the internal gear located at the front; A rotatable rear-side internal gear, wherein the rear-side internal gear is located at the rear of the front-side internal gear and has a different reduction ratio than the front-side internal gear; A locking component is disposed radially outside the front-side internal gear and the rear-side internal gear, and can be switched to a first position where it is locked to the front-side internal gear to restrict the rotation of the front-side internal gear, and a second position where it is locked to the rear-side internal gear to restrict the rotation of the rear-side internal gear. as well as The operation unit is capable of selectively switching the locking component to either the first position or the second position. The locking component is configured such that the middle part is supported and the two ends are swayable. In the first position, one end is locked to the outer periphery of the front-side internal gear, and in the second position, the other end is locked to the outer periphery of the rear-side internal gear.

2. The power tool according to claim 1, characterized in that, The deceleration unit is housed within a cylindrical casing. The operating unit includes: An annular component is configured to rotate along the outer periphery of the housing and is alternately formed in the circumferential direction with a first pressing portion that presses one end of the locking component from the radially outer side of the housing to switch the locking component to the first position, and a second pressing portion that presses the other end of the locking component from the radially outer side to switch the locking component to the second position. as well as A rotating operating component that allows the annular component to rotate at any angle around the outer periphery of the housing.

3. The power tool according to claim 2, characterized in that, The annular component has multiple teeth continuously formed along its circumference. A gear that meshes with the teeth is integrally formed on the rotating operating component.

4. The power tool according to claim 3, characterized in that, A gear ring with the teeth formed thereon is integrally provided on the annular component.

5. The power tool according to any one of claims 2 to 4, characterized in that, The annular component is a frame-like body in which the first pressing part and the second pressing part protrude differently in the axial direction and extend meanderingly in the circumferential direction.

6. The power tool according to any one of claims 2 to 4, characterized in that, The locking components are provided in multiple ways.

7. The power tool according to claim 6, characterized in that, The locking component is positioned at a point symmetrical about the axis of the internal gear.

8. The power tool according to any one of claims 2 to 4, characterized in that, On the outer periphery of the front-side internal gear and the rear-side internal gear, a plurality of locking ribs extending along the axial direction are provided at predetermined intervals along the circumference of the internal gear. The two ends of the locking member have locking portions that lock with the locking rib in the circumferential direction.

9. The power tool according to claim 8, characterized in that, The locking portion is formed in a curled shape.

10. The power tool according to any one of claims 2 to 4, characterized in that, The front-side internal gear and the rear-side internal gear are arranged adjacent to each other in the axial direction, and a sealing member is sandwiched between their opposing surfaces. On the other hand, flange portions extending toward the center are formed at the ends of the opposing surfaces of the front internal gear and the rear internal gear, respectively.

11. The power tool according to any one of claims 2 to 4, characterized in that, The reduction gear has another internal gear rotatably, which is configured to slide in a first sliding position where it is restricted from rotating within the housing that houses the reduction gear, causing the planetary gear to revolve, and in a second sliding position where it is not restricted from rotating within the housing and simultaneously meshes with the planetary gear and the gear carrier. By combining the rotational restriction of either the front-side internal gear or the rear-side internal gear based on the locking component with the sliding position of the other internal gear, it is possible to select more than 3 speed levels.

12. The power tool according to claim 1, characterized in that, The gear carrier rotates by means of the motor; The deceleration unit also has: A pin, which is held in the gear carrier; as well as Input gear, The planetary gears include: A first planetary gear, which is held on the pin and has a first number of teeth; as well as A second planetary gear, having a different number of teeth than the first planetary gear, is capable of rotating in the same direction as the first planetary gear via the input gear. The front-side internal gear meshes with the first planetary gear. The rear internal gear meshes with the second planetary gear. The first planetary gear, the second planetary gear, the front-side internal gear, the rear-side internal gear, and the pin are configured such that the first relative angular velocity between the first planetary gear and the second planetary gear is slower than the second relative angular velocity between the second planetary gear and the pin.

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