power tools

Abstract

This allows for more reliable gear shifting. [Solution] The power tool includes a motor, an output unit provided in front of the motor, a variable-speed reduction mechanism positioned between the motor and the output unit, a cylindrical part having a radial through hole, and a plurality of bracket bosses provided on the outer circumference of the cylindrical part, a gear case housing the reduction mechanism inside the cylindrical part, a motor bracket fixed to the plurality of bracket bosses, a switching operation unit for changing speeds, and a switching wire passing through the through hole and connecting the switching operation unit and the reduction mechanism. The switching wire, viewed from the axial direction, includes a first portion extending from the switching operation unit to the cylindrical part, a second portion extending circumferentially along the outer surface of the cylindrical part from the end of the first portion, and a third portion inserted through the through hole from the end of the second portion. The plurality of bracket bosses are provided on the outer circumference of the cylindrical part at positions other than the first region radially opposite to the second portion.

Description

Technical Field

[0001] The technology disclosed in this specification relates to power tools.

Background Art

[0002] In the technical field related to power tools, a driver drill equipped with a speed change function as disclosed in Patent Document 1 is known. By moving the speed change lever to the low-speed mode position, the medium-speed mode position, and the high-speed mode position respectively, the reduction ratio of the reduction mechanism is switched. Patent Document 1 discloses a configuration in which the speed change lever and an internal gear for speed change are connected by a switching wire, and the internal gear is arranged at a speed change position corresponding to the position of the speed change lever via the switching wire.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a state where the speed change lever is arranged at the position of any speed mode, the internal gear is held at the speed change position by the switching wire. In order to surely switch the speed mode, it is desirable to suppress the displacement of the position of the movable part (internal gear) for speed change due to the reaction force from other gears or the vibration during the operation of the power tool. The technology disclosed in this specification aims to enable more reliable speed change switching.

Means for Solving the Problems

[0005] This specification discloses a power tool. The power tool may include a motor, an output unit located in front of the motor and driven by the motor, a variable-speed reduction mechanism positioned between the motor and the output unit, a cylindrical portion having a radial through hole, a plurality of bracket bosses provided on the outer circumference of the cylindrical portion, a gear case housing the reduction mechanism inside the cylindrical portion, a motor bracket positioned between the motor and the reduction mechanism and fixed to the plurality of bracket bosses with screws, a switching operation unit that switches the speed of the reduction mechanism by moving, and a switching wire that passes through the through hole of the gear case and connects the switching operation unit and the reduction mechanism. The switching wire may include, viewed from the axial direction, a first portion extending from the switching operation unit to the cylindrical portion, a second portion extending circumferentially from the end of the first portion along the outer surface of the cylindrical portion, and a third portion inserted through the through hole from the end of the second portion. The plurality of bracket bosses may be provided on the outer circumference of the cylindrical portion at positions other than the first region radially opposite to the second portion.

[0006] The power tool may also include a motor, an output unit located in front of the motor and driven by the motor, a variable-speed reduction mechanism positioned between the motor and the output unit, a gear case including a cylindrical part with a radial through hole and housing the reduction mechanism inside the cylindrical part, a motor bracket positioned between the motor and the reduction mechanism and fixed to the gear case with screws, a switching operation unit that switches the speed of the reduction mechanism by moving, and a switching wire that passes through the through hole of the gear case and connects the switching operation unit and the reduction mechanism. The switching wire may include a held portion that is held by the switching operation unit. The gear case may include a first screw fixing portion that fixes the motor bracket at a position facing radially from the held portion of the switching wire when viewed from the axial direction. [Effects of the Invention]

[0007] The technology disclosed herein makes it possible to perform gear shifting more reliably. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a front perspective view showing a power tool according to an embodiment. [Figure 2] Figure 2 is a rear perspective view showing a power tool according to an embodiment. [Figure 3] Figure 3 is a side view showing an electric power tool according to an embodiment. [Figure 4] Figure 4 is a cross-sectional view showing a power tool according to an embodiment. [Figure 5] Figure 5 is a cross-sectional view showing a part of a power tool according to an embodiment. [Figure 6] Figure 6 is a perspective view from the front right showing a part of the reduction mechanism according to the embodiment. [Figure 7] Figure 7 is a front perspective view showing a part of the power tool according to the embodiment. [Figure 8] Figure 8 is a side view showing a part of the power tool according to the embodiment. [Figure 9] Figure 9 is a cross-sectional view showing a part of a power tool according to an embodiment. [Figure 10] Figure 10 is an exploded perspective view from the front showing the reduction mechanism according to the embodiment. [Figure 11] Figure 11 is a rear perspective view showing a part of the reduction mechanism according to the embodiment. [Figure 12] Figure 12 is a side view showing a speed switching mechanism according to an embodiment. [Figure 13] Figure 13 is a perspective view from the lower right rear showing the speed switching mechanism according to the embodiment. [Figure 14] Figure 14 is a view from above of the power tool when the reduction mechanism according to the embodiment is set to low-speed mode. [Figure 15] Figure 15 is a cross-sectional view showing the reduction mechanism according to the embodiment when it is set to low-speed mode. [Figure 16] Figure 16 is a view from above of the power tool when the reduction mechanism according to the embodiment is set to high-speed mode. [Figure 17]FIG. 17 is a cross-sectional view showing the speed reduction mechanism when the speed reduction mechanism according to the embodiment is set to the high speed mode. [Figure 18] FIG. 18 is a horizontal cross-sectional view seen from above of the engagement portion between the speed switching lever and the housing. [Figure 19] FIG. 19 is a perspective view from the rear showing the gear case, motor bracket, and gear housing according to the embodiment. [Figure 20] FIG. 20 is an exploded perspective view showing the gear case, motor bracket, and gear housing according to the embodiment from the rear. [Figure 21] FIG. 21 is a perspective view from below showing the speed switching lever and the switching wire according to the embodiment. [Figure 22] FIG. 22 is a perspective view from the rear showing the gear case and the switching wire according to the embodiment. [Figure 23] FIG. 23 is a view in the axial direction seen from the rear of the gear case and the switching wire according to the embodiment. [Figure 24] FIG. 24 is an enlarged view of the vicinity of the first part and the second part of the switching wire in FIG. 23. [Figure 25] FIG. 25 is a cross-sectional view in the axial direction seen from the rear of the plane passing through the second part of the switching wire. [Figure 26] FIG. 26 is a perspective explanatory view for explaining the mating surface between the gear case and the motor bracket. [Figure 27] FIG. 27 is a view in the axial direction seen from the front of the front surface of the motor bracket.

DETAILED DESCRIPTION OF THE INVENTION

[0009] In one or more embodiments, the power tool may include a motor, an output unit located in front of the motor and driven by the motor, a variable-speed reduction mechanism positioned between the motor and the output unit, a cylindrical portion having a radial through hole, a plurality of bracket bosses provided on the outer circumference of the cylindrical portion, a gear case housing the reduction mechanism inside the cylindrical portion, a motor bracket positioned between the motor and the reduction mechanism and fixed to the plurality of bracket bosses with screws, a switching operation unit that switches the speed of the reduction mechanism by moving, and a switching wire that passes through the through hole of the gear case and connects the switching operation unit and the reduction mechanism. The switching wire may include, viewed from the axial direction, a first portion extending from the switching operation unit to the cylindrical portion, a second portion extending circumferentially from the end of the first portion along the outer surface of the cylindrical portion, and a third portion inserted through the through hole from the end of the second portion. The plurality of bracket bosses may be provided on the outer circumference of the cylindrical portion at positions other than the first region radially opposite to the second portion.

[0010] In the above configuration, multiple bracket bosses on the gear case are provided at positions other than the first region radially opposite the second portion on the outer circumference of the cylindrical portion. If the bracket bosses were located in the first region, the second portion of the switching wire would have to bypass the outside of the bracket bosses. In contrast, in this configuration, the second portion of the switching wire can connect the first and third portions without bypassing the outside of the bracket bosses. This shortens the path length of the switching wire to the reduction mechanism, thus increasing the spring constant (rigidity) of the switching wire. With a higher spring constant, even if a reaction force acts on the gear connected by the switching wire, the switching wire is less likely to bend and can support the gear. As a result, misalignment of the gears for speed change in the reduction mechanism is less likely to occur, allowing for more reliable speed changeovers.

[0011] In one or more embodiments, the gear case may have through holes on one and the other lateral sides, respectively. The switching wire may include a one-side wire portion having a first portion, a second portion, and a third portion, which is inserted through the through hole on one side, and a other-side wire portion having a first portion, a second portion, and a third portion, which is inserted through the through hole on the other side. The plurality of bracket boss portions may include a first boss positioned between the first portion of the one-side wire portion and the first portion of the other-side wire portion.

[0012] In the above configuration, the first boss of the bracket boss can be positioned by utilizing the space between one wire section and the other wire section. This allows for the shortening of the switching wire path length while securing space for the bracket boss (first boss) without increasing the dimensions of the gear case or motor bracket.

[0013] In one or more embodiments, the switching operation unit may be positioned above the gear case. The multiple bracket bosses may include a second boss positioned in a second region on the outer circumference of the cylindrical portion that is below the through hole.

[0014] In the above configuration, by placing the second boss in the second region below the through-hole in the gear case where the switching wire is not located, the number of fixing points for the motor bracket can be increased without rerouting the switching wire. The first and second bosses firmly fix the gear case and the motor bracket, which helps to suppress issues such as lubricant (grease) leakage.

[0015] In one or more embodiments, the second boss may be located on one side and the other side of the cylindrical portion of the second region, respectively.

[0016] In the above configuration, by placing multiple second bosses in the second region of the gear case where the switching wire is not located, the fixing points of the motor bracket to the gear case can be distributed over a wide area in the circumferential direction. As a result, the motor bracket can be fixed more evenly by the first boss and the multiple second bosses. Even in this case, the switching wire does not need to detour around the outside of each boss, which improves the reliability of gear shifting.

[0017] In one or more embodiments, the radial distance between the second portion of the switching wire and the outer circumferential surface of the first region of the cylindrical portion may be smaller than the amount of protrusion of the bracket boss portion relative to the outer circumferential surface of the first region.

[0018] In the above configuration, the gap between the cylindrical part of the gear case and its outer surface becomes sufficiently small. This effectively shortens the path length of the second portion of the switching wire, thereby effectively increasing the spring constant of the switching wire and further improving the performance of holding the position of the gear for speed shifting.

[0019] In one or more embodiments, the gear case may further include a gear housing located in front of the gear case, to which the front end of the gear case is fixed. The gear case may include a number of housing bosses located radially outward from the switching wire and screwed to the gear housing.

[0020] In the above configuration, the gear case can be fixed to the gear housing by multiple housing bosses, separate from the bracket boss. Even in this case, since the multiple housing bosses are positioned radially outside the switching wire, the switching wire does not need to detour around the outside of the housing bosses, thus avoiding an increase in the switching wire's path length.

[0021] In one or more embodiments, the housing bosses may include a third boss located radially outward from the second portion of the switching wire in the first region.

[0022] In the above configuration, in the first region where the bracket boss is not located, space for the housing boss (third boss) can be secured without having to reroute the second portion of the switching wire.

[0023] In one or more embodiments, the third boss may have a notch on its outer circumference facing the radial center of the cylindrical portion to allow the switching wire to pass through.

[0024] In the above configuration, by providing a notch in the third boss, which is positioned radially outward from the second portion of the switching wire, the radial position of the third boss can be brought closer to the second portion. This makes it possible to suppress an increase in the external dimensions of the gear case even when the third boss is positioned outside the second portion of the switching wire.

[0025] In one or more embodiments, the gear case may have through holes on one and the other lateral sides, respectively. The switching wire may include a one-wire portion having a first portion, a second portion, and a third portion, which is inserted through the through hole on one side, and a other-wire portion having a first portion, a second portion, and a third portion, which is inserted through the through hole on the other side. The third boss may be positioned outside the second portion of the one-wire portion and outside the second portion of the other-wire portion, respectively.

[0026] In the above configuration, by placing a third boss on the outside of the second portion of one wire section and on the outside of the second portion of the other wire section, the fixing points between the gear case and the gear housing can be distributed over a wide area. This allows the gear case to be fixed more evenly.

[0027] In one or more embodiments, the switching operation unit may be positioned above the gear case. The multiple housing bosses may include a fourth boss positioned in a second region below the through hole on the outer circumference of the cylindrical portion.

[0028] In the above configuration, by positioning the fourth boss in the second region of the gear case where the switching wire is not located, the fixing points of the gear case to the gear housing can be distributed over a wide area in the circumferential direction. As a result, the gear case can be fixed more evenly by the third and fourth bosses.

[0029] In one or more embodiments, the power tool may include a motor, an output unit located in front of the motor and driven by the motor, a variable-speed reduction mechanism positioned between the motor and the output unit, a gear case including a cylindrical portion having a radial through hole and housing the reduction mechanism inside the cylindrical portion, a motor bracket positioned between the motor and the reduction mechanism and fixed to the gear case with screws, a switching operation unit that switches the speed of the reduction mechanism by moving, and a switching wire that passes through the through hole of the gear case and connects the switching operation unit and the reduction mechanism. The switching wire may include a held portion that is held by the switching operation unit. The gear case may include a first screw fixing portion that fixes the motor bracket at a position facing radially from the held portion of the switching wire when viewed from the axial direction.

[0030] In the above configuration, the first screw fixing part that secures the motor bracket is positioned in the gear case, radially opposite the part of the gear case where the switching wire is held, when viewed from the axial direction. If the first screw fixing part were located in the middle of the path to the reduction mechanism, the switching wire would have to detour around the outside of the first screw fixing part. In contrast, in this configuration, the switching wire can be connected to the connection point with the reduction mechanism without detouring around the outside of the first screw fixing part from the part where it is held. This shortens the path length of the switching wire to the reduction mechanism, thus increasing the spring constant (rigidity) of the switching wire. With a higher spring constant of the switching wire, even if a reaction force acts on the gear connected by the switching wire, the switching wire is less likely to bend and can support the gear. As a result, misalignment of the gears for speed change in the reduction mechanism is less likely to occur, so speed change can be performed more reliably.

[0031] In one or more embodiments, a first screw fixing portion may be provided in the gear case in a region facing the switching wire radially when viewed from the axial direction. In the gear case in a region not facing the switching wire radially when viewed from the axial direction, a plurality of second screw fixing portions for fixing the motor bracket may be provided.

[0032] In the above configuration, only one first screw fixing point is provided in the opposing region, so the switching wire does not need to bypass the screw fixing point. Since multiple second screw fixing points are provided in the non-opposing region, the motor bracket and gear case can be evenly fixed at multiple points while avoiding increasing the path length of the switching wire.

[0033] In one or more embodiments, the gear case may be fixed to the motor bracket at three points arranged in a triangular shape when viewed from the axial direction, by one first screw fixing point located in an opposing region and two second screw fixing points located on one and the other lateral sides of the center of the gear case in a non-opposing region.

[0034] In the above configuration, the motor bracket and gear case are fixed at three points arranged in a triangular shape when viewed from the axial direction, which allows for even and firm fixing of the motor bracket and gear case while avoiding the need to increase the path length of the switching wire.

[0035] In one or more embodiments, the gear case may have a circumferentially flat first mating surface on its rear end face facing the motor bracket. The motor bracket may have a circumferentially flat second mating surface on its front face facing the gear case, which abuts against the first mating surface.

[0036] In the above configuration, the first mating surface of the gear case and the second mating surface of the motor bracket can be brought into flat surface contact with each other. This effectively suppresses leakage of lubricant (grease) inside the gear case even when vibrations occur due to the motor's operation.

[0037] In one or more embodiments, the gear case may further include a gear housing located in front of the gear case, to which the front end of the gear case is fixed. The gear case may also include two third screw fixings positioned in the circumferential direction between a first screw fixing and a second screw fixing on one side, and between a first screw fixing and a second screw fixing on the other side.

[0038] In the above configuration, the screw fastening points between the gear case and the gear housing (third screw fastening point) can be positioned circumferentially offset from the screw fastening points between the gear case and the motor bracket (first screw fastening point, second screw fastening point). This improves the workability of each screw fastening operation.

[0039] In one or more embodiments, the gear case may include a fourth screw fastening portion located between two second screw fastening portions on one side and the other side in a non-facing region. The gear case may be fastened to the gear housing at three locations arranged in an inverted triangular shape when viewed from the axial direction, by the two third screw fastening portions and the fourth screw fastening portion.

[0040] In the above configuration, the motor bracket and gear case are fixed at three points arranged in a triangular shape when viewed from the axial direction, and the gear case and gear housing are fixed at three points arranged in an inverted triangular shape when viewed from the axial direction. This allows for even fixing of the motor bracket and gear case, and the gear case and gear housing, while improving the workability of the screw tightening work for each.

[0041] The embodiments described below will be explained with reference to the drawings, but the disclosure is not limited thereto. The components of the embodiments described below can be combined as appropriate. In addition, some components may not be used.

[0042] In the embodiments, the terms left, right, front, rear, top, and bottom are used to describe the positional relationships of each part. These terms indicate relative positions or directions with respect to the center of the power tool.

[0043] The power tool has a motor. In this embodiment, the direction parallel to the rotation axis AX of the motor is appropriately referred to as the axial direction, the direction that rotates around the rotation axis AX is appropriately referred to as the circumferential direction or rotational direction, and the radial direction of the rotation axis AX is appropriately referred to as the radial direction.

[0044] In this embodiment, the rotation axis AX extends in the front-rear direction. The axial direction and the front-rear direction coincide. One side in the axial direction is the front, and the other side in the axial direction is the rear. Furthermore, in the radial direction, the position close to or approaching the rotation axis AX is appropriately referred to as the radially inward direction, and the position far from or away from the rotation axis AX is appropriately referred to as the radially outward direction.

[0045] [Overview of Power Tools] Figure 1 is a front perspective view showing the power tool 1 according to the embodiment. Figure 2 is a rear perspective view showing the power tool 1 according to the embodiment. Figure 3 is a side view showing the power tool 1 according to the embodiment. Figure 4 is a cross-sectional view showing the power tool 1 according to the embodiment. In this embodiment, the power tool 1 is a vibration driver drill.

[0046] As shown in Figures 1, 2, 3, and 4, the power tool 1 comprises a housing 2, a rear cover 3, a casing 4, a battery mounting section 5, a motor 6, a power transmission mechanism 7, an output section 8, a fan 9, a trigger lever 10, a forward / reverse switching lever 11, a speed switching lever 12 which is a switching operation section, a mode switching ring 13, a light 14, and a controller 17.

[0047] Housing 2 is made of synthetic resin. In this embodiment, housing 2 is made of nylon. Housing 2 includes a left housing 2L and a right housing 2R. The left housing 2L and the right housing 2R are fixed together by screws 2S. Housing 2 is formed by fixing the left housing 2L and the right housing 2R together.

[0048] The housing 2 includes a motor housing section 21, a grip section 22, and a battery holding section 23.

[0049] The motor housing 21 houses the motor 6. The motor housing 21 is cylindrical in shape. The motor housing 21 is positioned to surround the motor 6.

[0050] The grip portion 22 is held by the operator. The grip portion 22 is located below the motor housing portion 21. The grip portion 22 extends downward from the motor housing portion 21. The trigger lever 10 is located at the front of the grip portion 22.

[0051] The battery holder 23 houses the controller 17. The battery holder 23 is located below the grip portion 22. The battery holder 23 is connected to the lower end of the grip portion 22. In both the front-to-back and left-to-right directions, the external dimensions of the battery holder 23 are larger than the external dimensions of the grip portion 22.

[0052] The rear cover 3 is made of synthetic resin. The rear cover 3 is positioned behind the motor housing 21. The rear cover 3 is positioned to cover the rear of the motor 6. The rear cover 3 houses the fan 9. The rear cover 3 is positioned to cover the rear opening of the motor housing 21. The rear cover 3 is fixed to the motor housing 21 by screws 3S.

[0053] The motor housing 21 has an air intake port 18. The rear cover 3 has an exhaust port 19. Air from the external space of the housing 2 flows into the internal space of the housing 2 through the air intake port 18. Air from the internal space of the housing 2 flows out into the external space of the housing 2 through the exhaust port 19.

[0054] The casing 4 houses the power transmission mechanism 7. The casing 4 includes a gear case 4A, a gear housing 4B, a motor bracket 4C, and a stop plate 4D. The gear housing 4B is located in front of the gear case 4A. The mode switching ring 13 is located in front of the gear housing 4B. The gear case 4A is made of synthetic resin. The gear housing 4B is made of metal. In this embodiment, the gear housing 4B is made of aluminum. The casing 4 is connected to the front of the motor housing 21. Both the gear case 4A and the gear housing 4B are cylindrical.

[0055] The front end of the gear case 4A is fixed to the gear housing 4B. The gear case 4A is fixed to the rear end of the gear housing 4B. The motor bracket 4C is made of synthetic resin. The motor bracket 4C is positioned to cover the opening at the rear end of the gear case 4A. The motor bracket 4C is fixed to the rear end of the gear case 4A. The stop plate 4D is positioned to cover the opening at the front end of the gear housing 4B. The stop plate 4D is fixed to the front end of the gear housing 4B by screws 4F (see Figure 5).

[0056] The casing 4 is positioned to cover the front opening of the motor housing 21. The gear case 4A is positioned inside the motor housing 21. The gear housing 4B is fixed to the motor housing 21 by screws 4S.

[0057] The battery mounting section 5 is formed at the bottom of the battery holding section 23. The battery mounting section 5 is connected to the battery pack 20. The battery pack 20 is mounted in the battery mounting section 5. The battery pack 20 is detachable from the battery mounting section 5. The battery pack 20 includes a secondary battery. In an embodiment, the battery pack 20 includes a rechargeable lithium-ion battery. By being mounted in the battery mounting section 5, the battery pack 20 can supply power to the power tool 1. The motor 6 is driven based on the power supplied from the battery pack 20. The controller 17 operates based on the power supplied from the battery pack 20.

[0058] Motor 6 is the power source of the power tool 1. Motor 6 is an inner-rotor type brushless motor. Motor 6 is housed in the motor housing 21. Motor 6 has a cylindrical stator 61 and a rotor 62 positioned inside the stator 61. The rotor 62 rotates relative to the stator 61. The rotor 62 includes a rotor shaft 63 that extends in the axial direction.

[0059] The power transmission mechanism 7 is positioned in front of the motor 6. The power transmission mechanism 7 is housed in the casing 4. The power transmission mechanism 7 connects the rotor shaft 63 and the output unit 8. The power transmission mechanism 7 transmits the power generated by the motor 6 to the output unit 8. The power transmission mechanism 7 has multiple gears.

[0060] The power transmission mechanism 7 includes a reduction mechanism 30 and a vibration mechanism 40.

[0061] The reduction gear mechanism 30 is positioned between the motor 6 and the output unit 8. The reduction gear mechanism 30 reduces the rotation of the rotor 62 (rotor shaft 63) to rotate the output unit 8 at a lower rotational speed than the rotor 62. The reduction gear mechanism 30 is variable speed (i.e., the reduction ratio can be changed). The reduction gear mechanism 30 includes a gear mechanism connected to a speed switching lever 12. The reduction ratio of the reduction gear mechanism 30 is switched by changing the meshing position of the gear mechanism according to the switching position of the speed switching lever 12. In this embodiment, the reduction gear mechanism 30 has a first planetary gear mechanism 31, a second planetary gear mechanism 32, and a third planetary gear mechanism 33. At least a portion of the first planetary gear mechanism 31 is positioned in front of the motor 6. The second planetary gear mechanism 32 is positioned in front of the first planetary gear mechanism 31. The third planetary gear mechanism 33 is positioned in front of the second planetary gear mechanism 32. The first planetary gear mechanism 31 is operated by the rotational force of the motor 6. The second planetary gear mechanism 32 is operated by the rotational force of the first planetary gear mechanism 31. The third planetary gear mechanism 33 is operated by the rotational force of the second planetary gear mechanism 32.

[0062] The vibration mechanism 40 vibrates the output unit 8 in the axial direction. The vibration mechanism 40 includes a first cam 41, a second cam 42, and a vibration switching ring 43.

[0063] The output unit 8 is positioned in front of the motor 6. The output unit 8 is driven by the motor 6; that is, the output unit 8 rotates based on the rotational force transmitted from the rotor 62. The output unit 8 rotates with the tool attached based on the rotational force transmitted from the rotor 62 via the power transmission mechanism 7. The output unit 8 has a spindle 81 that rotates around the rotation axis AX based on the rotational force transmitted from the rotor 62, and a chuck 82 attached to the spindle 81 that can hold the tool. The tool is held in the chuck 82. The front end of the chuck 82 is positioned in front of the casing 4. At least a portion of the spindle 81 is positioned in front of the third planetary gear mechanism 33. The spindle 81 is connected to the third planetary gear mechanism 33. The spindle 81 rotates due to the rotational force of the rotor 62 transmitted via the first planetary gear mechanism 31, the second planetary gear mechanism 32, and the third planetary gear mechanism 33.

[0064] The fan 9 is positioned behind the motor 6. The fan 9 generates an airflow to cool the motor 6. The fan 9 is fixed to at least a portion of the rotor 62. The fan 9 is fixed to the rear of the rotor shaft 63. The fan 9 rotates with the rotation of the rotor shaft 63. As the rotor shaft 63 rotates, the fan 9 rotates together with the rotor shaft 63. As the fan 9 rotates, air from the external space of the housing 2 flows into the internal space of the housing 2 through the intake port 18. The air that flows into the internal space of the housing 2 cools the motor 6 by circulating through the internal space of the housing 2. The air that has circulated through the internal space of the housing 2 flows out into the external space of the housing 2 through the exhaust port 19.

[0065] The trigger lever 10 is operated to start the motor 6. The trigger lever 10 is located on the upper part of the grip portion 22. The front end of the trigger lever 10 protrudes forward from the front of the grip portion 22. The trigger lever 10 is movable in the forward and backward directions. The trigger lever 10 is operated by the operator. When the trigger lever 10 is moved backward, the motor 6 is started. When the operation of the trigger lever 10 is released, the motor 6 stops.

[0066] The forward / reverse rotation lever 11 is operated to switch the rotation direction of the motor 6. The forward / reverse rotation lever 11 is located on the upper part of the grip section 22. The left end of the forward / reverse rotation lever 11 protrudes to the left from the left side of the grip section 22. The right end of the forward / reverse rotation lever 11 protrudes to the right from the right side of the grip section 22. The forward / reverse rotation lever 11 is movable in the left and right directions. The forward / reverse rotation lever 11 is operated by the operator. When the forward / reverse rotation lever 11 is operated to the left, the motor 6 rotates in the forward direction. When the forward / reverse rotation lever 11 is operated to the right, the motor 6 rotates in the reverse direction. Switching the rotation direction of the motor 6 switches the rotation direction of the spindle 81.

[0067] The speed switching lever 12 is a switching operation unit operated to change the speed mode (gear stage) of the reduction mechanism 30. The speed switching lever 12 is located on the upper part of the motor housing 21. The speed switching lever 12 is located above the casing 4. The speed switching lever 12 changes the speed of the reduction mechanism 30 by moving it. The speed switching lever 12 is operated by an operator. The speed switching lever 12 is movable in the forward and backward directions. The speed modes of the reduction mechanism 30 include a low-speed mode and a high-speed mode. That is, the reduction mechanism 30 is capable of two-speed gear changes. The low-speed mode is a speed mode in which the output unit 8 rotates at a first rotational speed (low speed) while the rotor 62 is rotating at a constant rotational speed. The high-speed mode is a speed mode in which the output unit 8 rotates at a second rotational speed (high speed) that is higher than the first rotational speed while the rotor 62 is rotating at a constant rotational speed.

[0068] The mode switching ring 13 is operated to change the working mode of the vibration mechanism 40. The mode switching ring 13 is located at the front of the casing 4. The mode switching ring 13 is rotatable. The mode switching ring 13 is operated by an operator. The working modes of the vibration mechanism 40 include vibration mode and non-vibration mode. Vibration mode refers to a working mode in which the output unit 8 is vibrated in the axial direction. Non-vibration mode refers to a working mode in which the output unit 8 is not vibrated in the axial direction. By operating the mode switching ring 13 to the vibration mode position in the rotational direction, the working mode of the vibration mechanism 40 is set to vibration mode. By operating the mode switching ring 13 to the non-vibration mode position in the rotational direction, the working mode of the vibration mechanism 40 is set to non-vibration mode.

[0069] Light 14 emits illumination light that illuminates the front of the power tool 1. Light 14 includes, for example, a light-emitting diode (LED). Light 14 is located at the lower front of the motor housing 21. Light 14 is located above the trigger lever 10.

[0070] The controller 17 includes a computer system. The controller 17 outputs control commands to control the motor 6. At least a portion of the controller 17 is housed in a controller case 26. The controller 17 is housed in the battery holder 23 while being held in the controller case 26. The controller 17 includes a circuit board on which multiple electronic components are mounted. Examples of electronic components mounted on the circuit board include a processor such as a CPU (Central Processing Unit), non-volatile memory such as ROM (Read Only Memory) or storage, volatile memory such as RAM (Random Access Memory), transistors, capacitors, and resistors.

[0071] [Motors and power transmission mechanisms] Figure 5 is a cross-sectional view showing a part of the power tool 1 according to an embodiment. As shown in Figure 5, the motor 6 has a cylindrical stator 61 and a rotor 62 disposed inside the stator 61. The rotor 62 includes a rotor shaft 63 that extends in the axial direction.

[0072] The stator 61 includes a stator core 61A comprising a plurality of stacked steel plates, a front insulator 61B positioned in front of the stator core 61A, a rear insulator 61C positioned behind the stator core 61A, a plurality of coils 61D wound around the stator core 61A via the front insulator 61B and the rear insulator 61C, a sensor circuit board 61E attached to the front insulator 61B, and a short-circuit member 61F supported by the front insulator 61B. The sensor circuit board 61E has a plurality of rotation detection elements for detecting the rotation of the rotor 62. The short-circuit member 61F connects the plurality of coils 61D via fused terminals. The short-circuit member 61F is connected to the controller 17 via lead wires.

[0073] The rotor 62 rotates around the axis of rotation AX. The rotor 62 has a rotor shaft 63, a rotor core 62A arranged around the rotor shaft 63, and a plurality of permanent magnets 62B held in the rotor core 62A. The rotor core 62A is cylindrical. The rotor core 62A includes a plurality of laminated steel plates. The rotor core 62A has through holes that extend in the axial direction. Multiple through holes are formed in the circumferential direction. The permanent magnets 62B are arranged in each of the plurality of through holes in the rotor core 62A.

[0074] The rotation detection element on the sensor circuit board 61E detects the rotation of the rotor 62 by detecting the magnetic field of the permanent magnet 62B. The controller 17 supplies a drive current to the coil 61D based on the detection data from the rotation detection element.

[0075] The rotor shaft 63 rotates around the rotation axis AX. The rotation axis AX of the rotor shaft 63 coincides with the rotation axis of the output unit 8. The front of the rotor shaft 63 is rotatably supported by a bearing 64. The rear of the rotor shaft 63 is rotatably supported by a bearing 65. The bearing 64 is held by a motor bracket 4C located in front of the stator 61. The motor bracket 4C rotatably supports the front of the rotor shaft 63 via the bearing 64. The bearing 65 is held by the rear cover 3. The front end of the rotor shaft 63 is positioned in front of the bearing 64. The front end of the rotor shaft 63 passes through the motor bracket 4C and is positioned in the internal space of the gear case 4A. The motor bracket 4C is positioned between the motor 6 and the reduction mechanism 30.

[0076] A pinion gear 31S is provided at the front end of the rotor shaft 63. The pinion gear 31S functions as the sun gear of the first planetary gear mechanism 31. The pinion gear 31S is rotated by the motor 6. The rotor shaft 63 is connected to the first planetary gear mechanism 31 of the reduction mechanism 30 via the pinion gear 31S.

[0077] Figure 6 is a perspective view from the front right showing a part of the reduction mechanism 30 according to the embodiment. The spindle 81 is connected to the third carrier 33C. In this embodiment, an engaging member 34 is provided on the outer circumference of the spindle 81. The engaging member 34 is fixed to the spindle 81. The engaging member 34 has projections 34A that protrude from the outer circumference in opposite directions. The third carrier 33C is arranged around the spindle 81. An engaging projection 35 that protrudes forward is provided on the front surface of the third carrier 33C. The engaging projection 35 contacts the projection 34A of the engaging member 34 in the circumferential direction. The contact between the engaging projection 35 and the projection 34A of the engaging member 34 prevents relative rotation between the third carrier 33C and the spindle 81. The rotation of the third carrier 33C causes the spindle 81 to rotate together with the third carrier 33C.

[0078] The spindle 81 is rotatably supported by bearings 83 and 84. While supported by bearings 83 and 84, the spindle 81 is movable in the forward and backward directions.

[0079] As shown in Figure 5, the spindle 81 has a flange portion 81F. A coil spring 87 is positioned between the flange portion 81F and the bearing 83. The flange portion 81F is in contact with the front end of the coil spring 87. The coil spring 87 generates an elastic force that moves the spindle 81 forward.

[0080] The chuck 82 is capable of holding a cutting tool. The chuck 82 is connected to the front of the spindle 81. A screw hole 81R is provided at the front end of the spindle 81. As the spindle 81 rotates, the chuck 82 rotates. The chuck 82 rotates while holding the cutting tool.

[0081] The first cam 41 and the second cam 42 of the vibration mechanism 40 are each positioned inside the gear housing 4B. In the front-rear direction, the first cam 41 and the second cam 42 are each positioned between bearing 83 and bearing 84.

[0082] The first cam 41 is ring-shaped. The first cam 41 is positioned around the spindle 81. The first cam 41 is fixed to the spindle 81. The first cam 41 rotates together with the spindle 81. Cam teeth are provided on the rear surface of the first cam 41. The first cam 41 is supported by a stop ring 44. The stop ring 44 is positioned around the spindle 81. In the front-rear direction, the stop ring 44 is positioned between the first cam 41 and the bearing 83.

[0083] The second cam 42 is ring-shaped. The second cam 42 is positioned behind the first cam 41. The second cam 42 is positioned around the spindle 81. The second cam 42 is rotatable relative to the spindle 81. Cam teeth are provided on the front surface of the second cam 42. The cam teeth on the front surface of the second cam 42 mesh with the cam teeth on the rear surface of the first cam 41. Claws are provided on the rear surface of the second cam 42.

[0084] In the front-rear direction, a support ring 45 is positioned between the second cam 42 and the bearing 84. The support ring 45 is positioned inside the gear housing 4B. The support ring 45 is fixed to the gear housing 4B. Multiple steel balls 46 are positioned on the front surface of the support ring 45. A washer 47 is positioned between the steel balls 46 and the second cam 42. The second cam 42 is rotatable within the space defined by the support ring 45 and the washer 47, with its front-rear movement restricted.

[0085] The vibration switching ring 43 switches between vibration mode and non-vibration mode. The mode switching ring 13 is connected to the vibration switching ring 43 via a cam ring 48. The mode switching ring 13 and the cam ring 48 are rotatable as a single unit. The vibration switching ring 43 holds the switching cam 43C so that it can move in the front-rear direction. The vibration switching ring 43 is inserted into a guide hole provided in the gear housing 4B. The rotation of the vibration switching ring 43 is restricted by a guide groove provided in the gear housing 4B. The switching cam 43C is biased forward by a spring 43E held in the gear housing 4B. When the mode switching ring 13 is operated in a predetermined direction by the operator, the switching cam 43C is pushed backward by the mode switching ring 13. When the mode switching ring 13 is operated in the opposite direction by the operator, the switching cam 43C is pushed back to its forward position by the spring 43E. The switching cam 43C switches between vibration mode and non-vibration mode by moving in the forward direction between a forward position and a backward position behind the forward position. The vibration mode and non-vibration mode are switched by operating the mode switching ring 13.

[0086] The vibration mode includes a state in which the rotation of the second cam 42 is restricted. The non-vibration mode includes a state in which the rotation of the second cam 42 is permitted. When the switching cam 43C moves to the forward position, the rotation of the second cam 42 is restricted. When the switching cam 43C moves to the retracted position, the rotation of the second cam 42 is permitted.

[0087] In the vibration mode, at least a portion of the switching cam 43C, which has moved to the forward position, comes into contact with the second cam 42. This contact between the switching cam 43C and the second cam 42 restricts the rotation of the second cam 42. When the motor 6 is driven while the rotation of the second cam 42 is restricted, the first cam 41, which is fixed to the spindle 81, rotates while contacting the cam teeth of the second cam 42. As a result, the spindle 81 rotates while vibrating in the front-back direction.

[0088] In non-vibration mode, the switching cam 43C, which has moved to the retracted position, separates from the second cam 42. The separation of the switching cam 43C and the second cam 42 allows the rotation of the second cam 42 to be permitted. When the motor 6 is driven while the rotation of the second cam 42 is permitted, the second cam 42 rotates together with the first cam 41 and the spindle 81. As a result, the spindle 81 rotates without vibrating in the front-rear direction.

[0089] The vibration switching ring 43 is positioned around the first cam 41 and the second cam 42. The switching cam 43C also has an opposing portion 43S that faces the rear surface of the second cam 42. The opposing portion 43S protrudes radially inward from the rear of the switching cam 43C.

[0090] When the mode switching ring 13 is operated and the switching cam 43C moves to the forward position, the claw on the rear surface of the second cam 42 comes into contact with the opposing part 43S of the switching cam 43C. This restricts the rotation of the second cam 42. In this way, by moving the switching cam 43C to the forward position, the vibration mechanism 40 is switched to vibration mode.

[0091] When the mode switching ring 13 is operated and the switching cam 43C moves to the retracted position, the opposing portion 43S of the switching cam 43C separates from the second cam 42. This allows the rotation of the second cam 42 to be permitted. In this way, by operating the mode switching ring 13 and moving the switching cam 43C to the retracted position, the vibration mechanism 40 is switched to a non-vibration mode.

[0092] Figure 7 is a front perspective view showing a part of the power tool 1 according to the embodiment. Figure 8 is a side view showing a part of the power tool 1 according to the embodiment. Figure 9 is a cross-sectional view showing a part of the power tool 1 according to the embodiment. Figure 10 is an exploded front perspective view showing the reduction mechanism 30 according to the embodiment. Figure 11 is a rear perspective view showing a part of the reduction mechanism 30 according to the embodiment. For convenience, the specific shapes of the teeth that mesh with each other have been omitted from the illustration in each figure.

[0093] The first planetary gear mechanism 31 includes a plurality of planetary gears 31P, a first carrier 31C supporting the plurality of planetary gears 31P, and an internal gear 31R arranged around the plurality of planetary gears 31P. A pinion gear 31S is provided at the front end of the rotor shaft 63 (see Figure 5). The pinion gear 31S functions as the sun gear of the first planetary gear mechanism 31. The pinion gear 31S is located on the front side of the stator 61. The pinion gear 31S is rotated by the rotor 62. The pinion gear 31S may be rotated directly or indirectly by the rotor 62. A plurality of planetary gears 31P are arranged around the pinion gear 31S.

[0094] The second planetary gear mechanism 32 includes a sun gear 32S, a plurality of planetary gears 32P arranged around the sun gear 32S, a second carrier 32C supporting the plurality of planetary gears 32P, and an internal gear 32R arranged around the plurality of planetary gears 32P. The sun gear 32S is positioned in front of the internal gear 31R. The sun gear 32S may be rotated directly or indirectly by the planetary gears 31P. The planetary gears 32P mesh with the sun gear 32S. The internal gear 32R meshes with the planetary gears 32P.

[0095] The third planetary gear mechanism 33 includes a sun gear 33S, a plurality of planetary gears 33P arranged around the sun gear 33S, a third carrier 33C supporting the plurality of planetary gears 33P, and an internal gear 33R arranged around the plurality of planetary gears 33P.

[0096] The gear case 4A and gear housing 4B are located in front of the stator 61. The gear case 4A houses the pinion gear 31S, planetary gear 31P, internal gear 31R, first carrier 31C, sun gear 32S, planetary gear 32P, and internal gear 32R. The gear housing 4B houses the second carrier 32C, sun gear 33S, planetary gear 33P, internal gear 33R, locking ring 37, and third carrier 33C.

[0097] The planetary gear 31P is rotatably supported by the first pin 31A. The first pin 31A is supported by the first carrier 31C. The first pin 31A protrudes rearward from the rear surface of the first carrier 31C. Multiple first pins 31A are provided at circumferential intervals. In this embodiment, five first pins 31A are provided at equal intervals in the circumferential direction. One planetary gear 31P is supported by each of the multiple (five) first pins 31A. The planetary gear 31P is positioned rearward of the first carrier 31C. The first carrier 31C rotatably supports the planetary gear 31P via the first pins 31A. An external gear 31K is provided on the outer circumference of the first carrier 31C. An internal gear 31R is arranged around the multiple planetary gears 31P.

[0098] The sun gear 32S is positioned in front of the first carrier 31C. The diameter of the sun gear 32S is smaller than the diameter of the first carrier 31C. The first carrier 31C and the sun gear 32S rotate together. The first carrier 31C and the sun gear 32S may be a single unit or separate parts. A pin 32A is provided on the second carrier 32C. The planetary gear 32P is rotatably supported by the pin 32A. The second carrier 32C rotatably supports the planetary gear 32P via the pin 32A.

[0099] The sun gear 33S is positioned in front of the second carrier 32C. The diameter of the sun gear 33S is smaller than the diameter of the second carrier 32C. The second carrier 32C and the sun gear 33S rotate together. The second carrier 32C and the sun gear 33S may be a single unit or separate parts. A pin 33A is provided on the third carrier 33C. The planetary gear 33P is rotatably supported by the pin 33A. The third carrier 33C rotatably supports the planetary gear 33P via the pin 33A. The third carrier 33C rotates together with the spindle 81 as described above.

[0100] Figure 12 is a side view showing the speed switching mechanism 36 according to the embodiment. Figure 13 is a perspective view from the lower right rear showing the speed switching mechanism 36 according to the embodiment. The reduction mechanism 30 has a speed switching mechanism 36. The speed switching mechanism 36 switches between a low-speed mode and a high-speed mode. In the embodiment, in the low-speed mode, the reduction function of the second planetary gear mechanism 32 is enabled. In the high-speed mode, the reduction function of the second planetary gear mechanism 32 is disabled. Enabling the second planetary gear mechanism 32 includes preventing the rotation of the internal gear 32R. Disabling the second planetary gear mechanism 32 includes allowing the rotation of the internal gear 32R.

[0101] The speed switching mechanism 36 includes a speed switching lever 12, a switching wire 50, and a locking ring 37. The speed switching mechanism 36 switches between low-speed mode and high-speed mode by moving the internal gear 32R in the forward and backward directions using the switching wire 50.

[0102] The switching wire 50 is a metal wire member with the required stiffness (spring constant) to move the internal gear 32R. The switching wire 50 is located on the outside of the gear case 4A. The switching wire 50 is movable in the front-rear direction on the outside of the gear case 4A. The tip of the switching wire 50 is inserted into a groove 32E provided in the internal gear 32R. As shown in Figures 7 and 8, a through hole 4J is provided in the gear case 4A. The switching wire 50 passes through the through hole 4J in the gear case 4A and connects the speed switching lever 12 and the reduction mechanism 30. The speed switching lever 12 is located above the gear case 4A. The upper end of the switching wire 50 is fixed to the lower surface of the speed switching lever 12. The tip of the switching wire 50 is located on the inside of the gear case 4A through the through hole 4J. The tip of the switching wire 50 is inserted into the groove 32E on the inside of the gear case 4A. The switching wire 50 and the internal gear 32R move together as a single unit in the front-to-back direction.

[0103] The upper part of the switching wire 50 is fixed to the speed switching lever 12. The speed switching lever 12 is positioned above the gear case 4A. The speed switching lever 12 holds the switching wire 50 on its lower surface facing the gear case 4A. The speed switching lever 12 and the switching wire 50 move together in the front-rear direction. Therefore, when the speed switching lever 12 is operated back and forth, the internal gear 32R moves back and forth along with the front-rear movement of the switching wire 50.

[0104] The locking ring 37 is located in front of the internal gear 32R. The locking ring 37 is housed in the gear housing 4B. The locking ring 37 is positioned between the inner surface of the gear housing 4B and the front end surface of the gear case 4A, preventing it from moving in the forward and backward directions. The locking ring 37 has a plurality of protrusions 37A on its outer circumference. The protrusions 37A are positioned inside the recess 4G (see Figure 7) formed on the front end surface of the gear case 4A, thereby preventing the locking ring 37 from rotating. The inner diameter of the locking ring 37 is larger than the outer diameter of the internal gear 32R. The internal gear 32R can be inserted into and removed from inside the locking ring 37. The inner circumference of the locking ring 37 has a plurality of cam teeth 37B.

[0105] Multiple cam teeth 32F are provided on the outer circumferential surface of the internal gear 32R. The cam teeth 32F are formed in front of the groove 32E. The cam teeth 32F can mesh with the cam teeth 37B of the locking ring 37. When the internal gear 32R is inserted inside the locking ring 37, the rotation of the internal gear 32R is prevented by the cam teeth 37B of the locking ring 37.

[0106] When the speed switching lever 12 is operated to move in the forward and backward direction, the switching wire 50 moves in the forward and backward direction, causing the internal gear 32R to move in the forward and backward direction. The movement of the internal gear 32R in the forward and backward direction switches between a state in which the internal gear 32R is inserted into the locking ring 37 and a state in which it is removed from the locking ring 37.

[0107] As the speed selector lever 12, the selector wire 50, and the internal gear 32R move forward, at least a portion of the internal gear 32R is inserted inside the locking ring 37, and the cam teeth 32F of the internal gear 32R and the cam teeth 37B of the locking ring 37 mesh, thereby preventing the rotation of the internal gear 32R. In other words, as the speed selector lever 12, the selector wire 50, and the internal gear 32R move forward and the rotation of the internal gear 32R is prevented, the second planetary gear mechanism 32 is activated.

[0108] As the speed selector lever 12, the selector wire 50, and the internal gear 32R move backward, the internal gear 32R is removed from the inside of the locking ring 37, and the cam teeth 32F of the internal gear 32R and the cam teeth 37B of the locking ring 37 separate, allowing the internal gear 32R to rotate. In other words, as the speed selector lever 12, the selector wire 50, and the internal gear 32R move backward and the rotation of the internal gear 32R is allowed, the second planetary gear mechanism 32 is deactivated.

[0109] When the second planetary gear mechanism 32 is activated, the internal gear 32R meshes only with the planetary gear 32P. When the second planetary gear mechanism 32 is deactivated, the internal gear 32R meshes with both the planetary gear 32P and the external gear 31K on the outer circumference of the first carrier 31C.

[0110] Figure 14 is a view of the power tool 1 from above when the reduction mechanism 30 according to the embodiment is set to low-speed mode. Figure 15 is a cross-sectional view showing the reduction mechanism 30 when the reduction mechanism 30 according to the embodiment is set to low-speed mode. Figure 16 is a view of the power tool 1 from above when the reduction mechanism 30 according to the embodiment is set to high-speed mode. Figure 17 is a cross-sectional view showing the reduction mechanism 30 when the reduction mechanism 30 according to the embodiment is set to high-speed mode. Figure 18 is a horizontal cross-sectional view from above showing the engagement point between the speed switching lever 12 and the housing 2.

[0111] The range of motion of the speed selector lever 12 is defined in the front-rear direction. The range of motion is linear along the front-rear direction. The range of motion is along the rotation axis AX. In this embodiment, the range of motion is defined by the inner periphery of an opening 2A formed in the housing 2. The opening 2A is formed in the upper part of the housing 2. The opening 2A exposes the upper surface of the speed selector lever 12. A knob portion 12A is formed on the upper surface of the speed selector lever 12, projecting upward into the opening 2A.

[0112] The speed switching lever 12 moves within a range of motion that includes multiple switching positions. In this embodiment, since the reduction mechanism 30 is a two-speed transmission, two switching positions, one for low-speed mode and one for high-speed mode, are defined within the range of motion. The switching position for low-speed mode is defined at the front end of the range of motion. The switching position for high-speed mode is defined at the rear end of the range of motion.

[0113] When the speed selector lever 12 is moved to the forward low-speed mode selection position, the speed mode of the reduction mechanism 30 is set to low-speed mode (1st gear). When the speed selector lever 12 is moved to the rear high-speed mode selection position (2nd gear), the speed mode of the reduction mechanism 30 is set to high-speed mode (2nd gear).

[0114] As shown in Figure 18, the speed selector lever 12 moves in the forward and backward direction while being guided by the housings 2 on both the left and right sides. The speed selector lever 12 is operated by an operator to move in the forward and backward direction. Leaf springs 12B (see Figure 7) having protrusions 12C are provided on both the left and right sides of the speed selector lever 12. The leaf springs 12B contact the guide surface 2G of the housing 2 at the protrusions 12C and slide along the guide surface 2G while deforming as the speed selector lever 12 moves. Engagement recesses 2H are formed in the guide surface 2G. When the protrusions 12C of the leaf springs 12B reach the position of the engagement recesses 2H, the restoring force of the leaf springs 12B causes the protrusions 12C to enter the engagement recesses 2H. By the protrusions 12C entering the engagement recesses 2H, the position of the speed selector lever 12 is maintained so that the speed selector lever 12 does not move due to unintended external forces. Engagement recesses 2H are formed at the switching position for low-speed mode and high-speed mode, respectively. When switching between low-speed mode and high-speed mode, applying an external force greater than a predetermined amount to the speed switching lever 12 causes the leaf spring 12B to deform, the protrusion 12C to disengage from the engagement recess 2H, and the engagement between the protrusion 12C and the engagement recess 2H is released, allowing the speed switching lever 12 to move.

[0115] As shown in Figures 14 and 15, when the speed switching lever 12 is in the low-speed mode switching position (the front end of the movable range), the switching wire 50 and the internal gear 32R are positioned in the front low-speed mode position. The internal gear 32R is inserted into the locking ring 37, and its rotation is prevented by the locking ring 37. With the internal gear 32R in the low-speed mode position, when the rotor shaft 63 is rotated by the drive of the motor 6, the pinion gear 31S rotates, and the planetary gear 31P revolves around the pinion gear 31S. Due to the revolution of the planetary gear 31P, the first carrier 31C and the sun gear 32S rotate at a rotational speed lower than the rotational speed of the rotor shaft 63. When the sun gear 32S rotates, the planetary gear 32P revolves around the sun gear 32S (the inner circumference of the internal gear 32R). Due to the revolution of the planetary gear 32P, the second carrier 32C and sun gear 33S rotate at a lower rotational speed than the first carrier 31C. In this way, when the motor 6 is driven with the internal gear 32R positioned in the low-speed mode, both the reduction function of the first planetary gear mechanism 31 and the reduction function of the second planetary gear mechanism 32 are activated, causing the second carrier 32C and sun gear 33S to rotate in low-speed mode.

[0116] As shown in Figures 16 and 17, when the speed switching lever 12 is in the high-speed mode switching position (the rear end of the movable range), the switching wire 50 and the internal gear 32R are positioned in the rear high-speed mode position. The internal gear 32R is removed from the locking ring 37 and allowed to rotate within the gear case 4A. With the internal gear 32R in the high-speed mode position, when the rotor shaft 63 is rotated by the drive of the motor 6, the pinion gear 31S rotates, and the planetary gear 31P revolves around the pinion gear 31S. Due to the revolution of the planetary gear 31P, the first carrier 31C and the sun gear 32S rotate at a rotational speed lower than the rotational speed of the rotor shaft 63. When the internal gear 32R is positioned in the high-speed mode, the internal gear 32R meshes with both the planetary gear 32P and the external gear 31K of the first carrier 31C, so the internal gear 32R and the first carrier 31C rotate together. Due to the rotation of the internal gear 32R, the planetary gear 32P revolves at the same orbital speed as the internal gear 32R. Due to the revolving of the planetary gear 32P, the second carrier 32C and the sun gear 33S rotate at the same rotational speed as the first carrier 31C. Thus, in high-speed mode, when the motor 6 is driven, the reduction function of the first planetary gear mechanism 31 is activated, but the reduction function of the second planetary gear mechanism 32 is not activated, and the second carrier 32C and the sun gear 33S rotate in high-speed mode.

[0117] [Mounting structure for switching wire and gear case] Next, the shape of the switching wire 50 and the mounting structure of the gear case 4A according to the embodiment will be described.

[0118] Figure 19 is a rear perspective view showing the gear case 4A, motor bracket 4C, and gear housing 4B according to the embodiment. Figure 20 is an exploded perspective view showing the gear case 4A, motor bracket 4C, and gear housing 4B according to the embodiment, viewed from the rear. Figure 21 is a bottom perspective view showing the speed switching lever 12 and switching wire 50 according to the embodiment. Figure 22 is a rear perspective view showing the gear case 4A and switching wire 50 according to the embodiment.

[0119] As shown in Figures 19 and 20, in this embodiment, the gear case 4A is individually fixed to the motor bracket 4C and the gear housing 4B by separate screws.

[0120] Specifically, the gear case 4A includes a cylindrical portion 70, a plurality of bracket boss portions 71, and a plurality of housing boss portions 72. The bracket boss portions 71 are screw receiving portions for which screws 4R for fixing the motor bracket 4C are attached. The motor bracket 4C is fixed to the plurality of bracket boss portions 71 with screws 4R. The housing boss portions 72 are screw insertion portions through which screws 4Q for fixing the gear case 4A to the gear housing 4B are inserted. The gear case 4A is fixed to the gear housing 4B by screws 4Q inserted through the plurality of housing boss portions 72.

[0121] As shown in Figure 21, the cylindrical portion 70 is the main body of the gear case 4A and has a cylindrical shape extending in the front-rear direction. The gear case 4A houses the reduction mechanism 30 inside the cylindrical portion 70. The front and rear ends of the cylindrical portion 70 are open. The end face (rear end face) of the rear end of the cylindrical portion 70 forms a first mating surface 73 with the motor bracket 4C. The front end of the cylindrical portion 70 is provided with a flange portion 74 extending radially outward. The outer circumferential surface 70A of the cylindrical portion 70 is composed of a circumferential curved surface over almost its entire length.

[0122] The cylindrical portion 70 has a radial through hole 4J. That is, the through hole 4J penetrates both the outer and inner surfaces of the cylindrical portion 70. The switching wire 50 is inserted through the through hole 4J. The through hole 4J is an elongated hole extending along the front-rear direction, allowing the switching wire 50 to move in the front-rear direction in conjunction with the operation of the speed switching lever 12. The length of the through hole 4J in the front-rear direction is equal to or greater than the range of movement of the switching wire 50 in the front-rear direction, i.e., the length of the movable range of the speed switching lever 12. The gear case 4A has through holes 4J on one and the other side (left-right direction). The one and the other side are, that is, the right side and the left side of the gear case 4A. The through holes 4J are located on both the left and right sides with respect to the central axis of the cylindrical portion 70.

[0123] Multiple bracket bosses 71 are provided on the outer circumference of the cylindrical portion 70. In this embodiment, three bracket bosses 71 are provided. Each bracket boss 71 is provided so as to protrude radially outward from the outer circumferential surface 70A of the cylindrical portion 70. Each bracket boss 71 extends in the front-rear direction from the front end to the rear end of the cylindrical portion 70. Screw holes 71H extending in the front-rear direction are formed in each bracket boss 71. Screws 4R are fitted into these screw holes 71H. As a result, the motor bracket 4C is fixed to each bracket boss 71 by the screws 4R.

[0124] Multiple housing bosses 72 are provided on the outer circumference of the cylindrical portion 70. In this embodiment, three housing bosses 72 are provided. Each housing boss 72 is provided at the front end of the cylindrical portion 70. Each housing boss 72 is provided radially outward from the outer circumferential surface 70A of the cylindrical portion 70 in the flange portion 74 of the gear case 4A. Each housing boss 72 has a greater thickness in the front-rear direction than other parts of the flange portion 74. Through holes 72H extending in the front-rear direction are formed in each housing boss 72. Screws 4Q are inserted through these through holes 72H. The screws 4Q that have passed through the through holes 72H are fitted into screw holes 4H formed in the gear housing 4B. As a result, the gear case 4A is fixed to the gear housing 4B by the screws 4Q that have passed through the three housing bosses 72.

[0125] The arrangement of the boss portions 71 for each bracket and the boss portions 72 for each housing in the gear case 4A will be described later.

[0126] As shown in Figures 21 to 24, the switching wire 50 includes, when viewed from the axial direction, a first portion 51 extending from the speed switching lever 12 to the cylindrical portion 70, a second portion 52 extending circumferentially from the end of the first portion 51 along the outer circumferential surface 70A of the cylindrical portion 70, and a third portion 53 inserted through the through hole 4J from the end of the second portion 52.

[0127] The switching wire 50 is inserted through a pair of through holes 4J on one side and the other side of the gear case 4A. That is, the switching wire 50 includes a one-way wire portion 50R inserted through the through hole 4J on one side (right side) and a other-way wire portion 50L inserted through the through hole 4J on the other side (left side). The one-way wire portion 50R has a first portion 51, a second portion 52, and a third portion 53. The other-way wire portion 50L also has a first portion 51, a second portion 52, and a third portion 53. The switching wire 50 is substantially symmetrical. The one-way wire portion 50R and the other-way wire portion 50L have the same structure and a shape that is symmetrical in the left-right direction. Substantially symmetrical means that even if there are unavoidable differences (asymmetrical shapes) such as dimensional tolerances, it is considered to be symmetrical.

[0128] One wire section 50R and the other wire section 50L are connected to each other at the first section 51. The switching wire 50 has a connecting section 54 that connects the upper end of the first section 51 of the one wire section 50R and the upper end of the first section 51 of the other wire section 50L. The connecting section 54 extends along the left-right direction. In this embodiment, the switching wire 50 is a single component composed of the one wire section 50R and the other wire section 50L connected at the connecting section 54. The one wire section 50R and the other wire section 50L may be separate components.

[0129] The first part 51 extends vertically between the speed switching lever 12 and the cylindrical portion 70. The first part 51 is linear. The upper end of the first part 51 connects to the connecting portion 54. The lower end of the first part 51 is positioned near the outer circumferential surface of the cylindrical portion 70 of the gear case 4A. The lower end of the first part 51 faces the outer circumferential surface of the cylindrical portion 70 with a small gap between them. The first part 51 is not in contact with the outer circumferential surface of the cylindrical portion 70.

[0130] The second portion 52 connects the end of the first portion 51 to the end of the third portion 53. The second portion 52 extends in an arc shape along the outer circumferential surface 70A of the cylindrical portion 70. The second portion 52 faces the outer circumferential surface 70A of the cylindrical portion 70 with a small gap between them.

[0131] The third portion 53 connects to the end of the second portion 52. The third portion 53 is positioned radially opposite the through hole 4J of the gear case 4A. The third portion 53 bends slightly forward from the end of the second portion 52 and then extends radially inward. The tip of the third portion 53 passes through the through hole 4J of the cylindrical portion 70 and is positioned inside the cylindrical portion 70. As a result, the tip of the third portion 53 is positioned inside the groove 32E of the internal gear 32R.

[0132] As shown in Figure 22, the switching wire 50 includes a retained portion 50F that is held by the speed switching lever 12. In this embodiment, the retained portion 50F includes a connecting portion 54. Specifically, a retaining groove 12T is formed on the lower surface of the speed switching lever 12, which is recessed upward and extends in the left-right direction. The connecting portion 54 at the upper end of the switching wire 50 fits inside the retaining groove 12T.

[0133] Furthermore, a pair of retaining legs 12L are provided on the lower surface of the speed switching lever 12, projecting downward toward the gear case 4A. One pair of retaining legs 12L is positioned on each of the left and right sides of the retaining groove 12T. The pair of retaining legs 12L extend toward the vicinity of the upper end of the second portion 52 of the switching wire 50 (just before the connection point with the first portion 51). The retaining groove 12T is continuous from the inner side surface to the lower end surface of the pair of retaining legs 12L. The inner side surface of the pair of retaining legs 12L is the side surface where the pair of retaining legs 12L face each other in the left-right direction. The retaining groove 12T extends vertically along the inner side surface of the pair of retaining legs 12L. The retaining groove 12T extends horizontally along the lower end surface of the pair of retaining legs 12L.

[0134] The upper ends of the first portion 51 and the second portion 52 of the switching wire 50 are fitted into retaining grooves 12T formed in a pair of retaining legs 12L. The first portion 51 is positioned within the retaining grooves 12T on the inner sides of the pair of retaining legs 12L. The upper end of the second portion 52 is fitted within the retaining grooves 12T formed on the lower end surfaces of the pair of retaining legs 12L. Therefore, in this embodiment, the retained portion 50F further includes the pair of first portions 51 and the upper end portions of the pair of second portions 52, in addition to the connecting portion 54. The switching wire 50 is fixed to the speed switching lever 12 by these portions being positioned within the retaining grooves 12T.

[0135] Next, the positional relationship between the switching wire 50 and the various parts of the gear case 4A will be described in detail. Figure 23 is a view of the gear case 4A and switching wire 50 according to the embodiment, seen from the rear in the axial direction. Figure 24 is an enlarged view of the vicinity of the first part 51 and the second part 52 of the switching wire 50 in Figure 23.

[0136] The gear case 4A according to this embodiment has a structure that allows for shortening the path length of the switching wire 50. In this specification, the path length of the switching wire 50 refers to the length of the switching wire 50 from the end of the holding portion of the switching wire 50 by the speed switching lever 12 (i.e., the holding leg portion 12L) to the bent portion on the tip side (the boundary portion between the second portion 52 and the third portion 53). The path length of the switching wire 50 corresponds to the length of the second portion 52.

[0137] Here, in order to determine the position of the gear case 4A, the following first region G1 and second region G2 are defined.

[0138] The first region G1 is the region on the outer circumference of the cylindrical portion 70 that is radially opposite to the second portion 52 of the switching wire 50. The first region G1 is the region included in the angular range of the circumferential direction of the cylindrical portion 70 from one end (the connection portion with the first portion 51) to the other end (the position of the through hole 4J). Since there is one wire portion 50R and the other wire portion 50L, the first region G1 exists on both the left and right sides of the cylindrical portion 70. The first region G1 can be said to be the region of the upper half of the outer circumferential surface 70A of the cylindrical portion 70, excluding the third region G3 between the pair of first portions 51.

[0139] The second region G2 is the area on the outer circumference of the cylindrical portion 70 that is below the through hole 4J. The second region G2 does not radially oppose the second portion 52 of the switching wire 50 on the outer circumference of the cylindrical portion 70. In this embodiment, since the through hole 4J is located on both the left and right sides (i.e., midway in the vertical direction) with respect to the central axis of the cylindrical portion 70, the second region G2 is the lower half of the outer surface 70A of the cylindrical portion 70. The second region G2 can also be described as a non-opposing region on the outer circumference of the cylindrical portion 70 that does not radially oppose the switching wire 50.

[0140] <Boss section for bracket> In this embodiment, the multiple bracket boss portions 71 of the gear case 4A are provided at positions other than the first region G1 on the outer circumference of the cylindrical portion 70 that are radially opposite to the second portion 52. None of the three bracket boss portions 71 are provided in the first region G1, and are provided outside the first region G1 in the circumferential direction of the cylindrical portion 70. Therefore, the second portion 52 of the switching wire 50 is not radially opposite to the bracket boss portion 71. As a result, the second portion 52 can be formed in an arc shape along the outer circumferential surface 70A of the cylindrical portion 70 without wrapping around the outer circumference of the bracket boss portion 71.

[0141] More specifically, the multiple bracket boss portions 71 include one first boss 71A and two second bosses 71B. The first boss 71A is positioned between the first portion 51 of one wire portion 50R and the first portion 51 of the other wire portion 50L. The first boss 71A is positioned in a third region G3 between a first region G1 on one side in the left-right direction and a first region G1 on the other side. The first boss 71A is provided at a position where the cylindrical portion 70 and the speed switching lever 12 face each other. That is, the first boss 71A is positioned at the upper end of the center of the cylindrical portion 70 in the left-right direction. The first boss 71A is provided at a position radially opposite the held portion 50F of the switching wire 50 when viewed from the axial direction. In the embodiment, the held portion 50F includes a pair of first portions 51 and a connecting portion 54 of the switching wire 50, and the first boss 71A is surrounded by the pair of first portions 51 and the connecting portion 54. In other words, the switching wire 50 has a rectangular recessed space that is recessed upwards, formed by the pair of first portions 51 and the connecting portion 54. The first boss 71A is positioned inside this rectangular recessed space.

[0142] The second boss 71B is positioned in a second region G2 on the outer circumference of the cylindrical portion 70, below the through hole 4J. The second boss 71B is positioned on one side and the other side of the cylindrical portion 70 within the second region G2. That is, the two second bosses 71B are positioned between the lateral end of the cylindrical portion 70 and the lower end of the cylindrical portion 70. In the left-right direction, the two second bosses 71B are positioned on one side (right) and the other side (left) of the first boss 71A.

[0143] In the example shown in Figure 23, when the upper end of the cylindrical portion 70 is set to 0 degrees around the central axis of the cylindrical portion 70, the first boss 71A is positioned at 0 degrees. The two second bosses 71B are positioned approximately 140 degrees apart on the right and left sides, respectively. Thus, in this embodiment, the three bracket bosses 71 are arranged in a triangular shape when viewed from the axial direction. The distance between each second boss 71B and the first boss 71A in the left-right direction is equal, and the three bracket bosses 71 are arranged in an isosceles triangle shape.

[0144] In this way, by providing the three bracket bosses 71 at locations other than the first region G1, the second portion 52 of the switching wire 50 does not need to wrap around the outside of the bracket bosses 71. Therefore, the second portion 52 can be brought closer to the first region G1 and extended along the first region G1, shortening the path length of the second portion 52. In addition, the first portion 51 and the connecting portion 54 are parts that protrude upward (radially outward) in order to connect to the speed switching lever 12, and by placing the first boss 71A in this portion rather than in the first region G1, the bracket bosses 71 do not increase the path length of the switching wire 50.

[0145] As shown in Figure 24, the radial distance CL between the second portion 52 of the switching wire 50 and the outer circumferential surface 70A of the first region G1 of the cylindrical portion 70 is smaller than the amount of protrusion EP of the bracket boss portion 71 relative to the outer circumferential surface 70A of the first region G1. The amount of protrusion EP of the bracket boss portion 71 relative to the outer circumferential surface 70A of the first region G1 is the difference between the radius R1 from the central axis of the cylindrical portion 70 to the outer circumferential surface 70A of the first region G1 and the radius R2 from the central axis of the cylindrical portion 70 to the outermost radial point of the bracket boss portion 71 (referred to as the outermost point). Of the three bracket boss portions 71, the first boss 71A has the smallest amount of protrusion EP. The distance CL is smaller than the amount of protrusion EP of the first boss 71A. The entire second portion 52 is located radially inward from the outermost point of the first boss 71A.

[0146] Furthermore, a regulating rib 70B (see Figure 21) is provided on the outer circumferential surface 70A of the cylindrical portion 70, at a position facing the second portion 52, which protrudes slightly radially outward. The regulating rib 70B is positioned slightly above the vicinity of the through hole 4J. In principle, the regulating rib 70B faces the second portion 52 radially without contact. The regulating rib 70B comes into contact with the second portion 52 when the second portion 52 is displaced (deformed) radially inward from its design position due to vibrations caused by the operation of the speed switching lever 12 or the operation of the power tool 1, or due to dimensional variations in the tolerance range, thereby preventing the second portion 52 from contacting the outer circumferential surface 70A of the cylindrical portion 70. For this reason, the second portion 52 is not in contact with the outer circumferential surface 70A of the cylindrical portion 70, except for the regulating rib 70B. The minimum value of the spacing CL of the second portion 52 corresponds to the height (protrusion amount) of the regulating rib 70B and is not zero. The height (protrusion) of the regulating rib 70B from the outer surface 70A of the cylindrical portion 70 is smaller than the wire diameter of the switching wire 50. The height (protrusion) of the regulating rib 70B is smaller than half the wire diameter of the switching wire 50. Also, the distance CL between the second portion 52 and the outer surface 70A excluding the regulating rib 70B is smaller than the wire diameter of the switching wire 50. In the example in Figure 24, the distance CL between the second portion 52 and the outer surface 70A excluding the regulating rib 70B is smaller than half the wire diameter of the switching wire 50.

[0147] Here, the switching wire 50 is fitted into the groove 32E with its tip elastically deformed backward when the switching wire 50 is in the low-speed mode position, which is the front end of its range of motion. Specifically, the switching wire 50 is designed so that, as shown in Figure 12, when the switching wire 50 is in the low-speed mode position, which is the front end of its range of motion, the tip of the third portion 53 is positioned at a design position DP that is shifted forward of the groove 32E.

[0148] When the switching wire 50 and the internal gear 32R are in the forward low-speed mode position, the front surface of the internal gear 32R comes into contact with the cam teeth 37B of the locking ring 37, preventing it from moving forward any further. As a result, the switching wire 50 undergoes elastic deformation, with its tip displaced backward from the design position DP to the position of the groove 32E. For convenience, this elastic deformation of the switching wire 50 is not depicted in the figures.

[0149] When the internal gear 32R is in the forward low-speed mode position, the tip of the switching wire 50 elastically deforms backward, and the switching wire 50 biases the internal gear 32R forward toward the locking ring 37 by its restoring force. Because the internal gear 32R is biased toward the locking ring 37, the position of the internal gear 32R is prevented from shifting backward. Therefore, even if the internal gear 32R is subjected to reaction forces from other gears or the locking ring 37, or vibrations during the operation of the power tool 1, the engagement state with the locking ring 37 is not unintentionally released due to the displacement of the internal gear 32R.

[0150] The magnitude of the forward biasing force acting on the internal gear 32R depends on the spring constant (stiffness) of the switching wire 50. In this embodiment, the path length of the switching wire 50 can be shortened, which increases the spring constant of the switching wire 50 and thus increases the biasing force on the internal gear 32R. As a result, unintended displacement of the internal gear 32R can be effectively suppressed, enabling more reliable gear shifting.

[0151] <Boss section for housing> As shown in Figures 21 and 23, the multiple housing bosses 72 are positioned radially outward from the switching wire 50. The multiple (three) housing bosses 72 include two third bosses 72A and one fourth boss 72B. Of these, the two third bosses 72A are positioned radially outward from the switching wire 50. The fourth boss 72B is positioned in the second region G2 where the switching wire 50 is not provided.

[0152] The third boss 72A is positioned in the first region G1 of the outer circumferential surface 70A of the cylindrical portion 70. One third boss 72A is provided in the first region G1 on one side where the one wire portion 50R is positioned, and one in the first region G1 on the other side where the other wire portion 50L is positioned. In other words, the third boss 72A is positioned outside the second portion 52 of the one wire portion 50R and outside the second portion 52 of the other wire portion 50L, respectively.

[0153] The third boss 72A is provided so as to protrude rearward from the flange portion 74 at the front end of the gear case 4A. The third boss 72A has a notch 72C on its outer circumference facing the radial center of the cylindrical portion 70 to allow the switching wire 50 to pass through. That is, the portion of the outer circumference of the third boss 72A that faces radially opposite the outer surface 70A of the cylindrical portion 70 is notched, and the surface of the notch 72C is formed to be approximately parallel to the outer surface 70A of the opposing cylindrical portion 70. The switching wire 50 is closest to the third boss 72A when it is positioned at the front end of the range of motion, that is, when the speed switching lever 12 is in the switching position for high speed mode. The notch 72C is provided so that the switching wire 50 does not come into contact with the third boss 72A in this state. The notch 72C allows the third boss 72A to be positioned outside the switching wire 50 while being closer to the radial inward position.

[0154] The fourth boss 72B is located in the second region G2 on the outer circumference of the cylindrical portion 70, below the through hole 4J. The fourth boss 72B is located between the two third bosses 72A in the left-right direction. The fourth boss 72B is located between the two second bosses 71B of the bracket boss portion 71 in the second region G2. The fourth boss 72B is located at the lower end of the cylindrical portion 70.

[0155] When the upper end of the cylindrical portion 70 is set to 0 degrees, the angle around the central axis of the cylindrical portion 70 is such that, in the example shown in Figure 23, the two third bosses 72A are positioned at approximately 47 degrees to the right and left, respectively. The fourth boss 72B is positioned at approximately 180 degrees. Thus, in this embodiment, the three housing bosses 72 are arranged in an inverted triangular shape when viewed from the axial direction. The left-right distance between each third boss 72A and the second boss 71B is equal, and the three housing bosses 72 are arranged in a downward-pointing isosceles triangle shape.

[0156] <Screw fixing part> With the above configuration, the gear case 4A separately includes a screw fixing part for fixing the motor bracket 4C and a screw fixing part for fixing to the gear housing 4B. Figure 25 is a cross-sectional view taken from the rear in the axial direction of the plane through which the second portion 52 of the switching wire 50 passes. In Figure 25, the reduction mechanism 30 inside the gear case 4A is simplified for convenience.

[0157] The gear case 4A includes a first screw fixing portion 75 for fixing the motor bracket 4C at a position facing radially from the held portion 50F of the switching wire 50 when viewed from the axial direction. The first screw fixing portion 75 is composed of a first boss 71A and a screw 4R. The motor bracket 4C is provided with an insertion hole 94 through which the screw 4R is inserted. The screw 4R, having passed through the insertion hole 94 from the rear of the motor bracket 4C, is fitted into the screw hole 71H of the first boss 71A.

[0158] In the gear case 4A, a first screw fixing portion 75 is provided in the opposing region GF that faces radially opposite the switching wire 50 when viewed from the axial direction. The opposing region GF is the region above the through hole 4J and includes both the pair of first regions G1 and the third region G3 between the pair of first regions G1 where the first boss 71A is provided.

[0159] Multiple (two) second screw fixing parts 76 for fixing the motor bracket 4C are provided in a non-opposing region of the gear case 4A that does not face the switching wire 50 radially when viewed from the axial direction. The non-opposing region is the region of the outer circumferential surface 70A of the cylindrical portion 70 where the switching wire 50 is not provided. The non-opposing region is the region below the through hole 4J and coincides with the second region G2. The non-opposing region is the region below the through hole 4J. The second screw fixing part 76 is composed of a second boss 71B and a screw 4R. The screw 4R, which passes through the insertion hole 94 from the rear of the motor bracket 4C, is fitted into the screw hole 71H of the second boss 71B.

[0160] Therefore, the gear case 4A is fixed to the motor bracket 4C at three points arranged in a triangular shape when viewed from the axial direction, by one first screw fixing part 75 located in the opposing region GF, and two second screw fixing parts 76 located on one side and the other side relative to the center of the gear case 4A in the non-opposing region (second region G2).

[0161] Furthermore, the gear case 4A includes two third screw fixing portions 77 positioned in the circumferential direction between the first screw fixing portion 75 and the second screw fixing portion 76 on one side, and between the first screw fixing portion 75 and the second screw fixing portion 76 on the other side. The third screw fixing portion 77 is composed of a third boss 72A and a screw 4Q. The screw 4Q, which passes through the insertion hole 72H of the third boss 72A from the rear of the gear case 4A, is mounted in the screw hole 4H of the gear housing 4B. In this embodiment, the third screw fixing portion 77 is positioned in the opposing region GF. Within the opposing region GF, the third screw fixing portion 77 is positioned radially outward from the second portion 52 in the first region G1 where the second portion 52 of the switching wire 50 is located.

[0162] The gear case 4A includes a fourth screw fixing portion 78 positioned between two second screw fixing portions 76 on one side and the other side in a non-opposing region (second region G2). The fourth screw fixing portion 78 is composed of a fourth boss 72B and a screw 4Q. The screw 4Q, which passes through the insertion hole 72H of the fourth boss 72B from the rear of the gear case 4A, is fitted into the screw hole 4H of the gear housing 4B.

[0163] Therefore, the gear case 4A is fixed to the gear housing 4B at three points arranged in an inverted triangular shape when viewed from the axial direction, by two third screw fixing points 77 and one fourth screw fixing point 78.

[0164] Figure 26 is a perspective view illustrating the mating surface between the gear case 4A and the motor bracket 4C. Figure 27 is a view of the front surface 90 of the motor bracket 4C, seen from the front in the axial direction.

[0165] As shown in Figure 26, the gear case 4A has a circumferential (annular) flat first mating surface 73 at its rear end face facing the motor bracket 4C. The first mating surface 73 includes the rear end face of the cylindrical portion 70 and the rear end faces of the three bracket boss portions 71 (first boss 71A and second boss 71B). The first mating surface 73 is a flat surface, and each position on the surface of the first mating surface 73 is at the same position in the front-rear direction.

[0166] The motor bracket 4C has a circumferential (annular) flat second mating surface 91 on its front surface 90 facing the gear case 4A, which contacts the first mating surface 73.

[0167] The motor bracket 4C has an opening 92 in the center. The front end of the rotor shaft 63 is inserted through the opening 92. A bearing 64 is placed in the opening 92. The motor bracket 4C rotatably supports the rotor shaft 63 via the bearing 64 in the opening 92. The front surface 90 of the motor bracket 4C is provided with four fitting ribs 93 that protrude forward. Each fitting rib 93 is formed in an arc shape to match the inner circumferential surface of the cylindrical portion 70 of the gear case 4A. When the motor bracket 4C is attached to the rear end surface of the gear case 4A, each fitting rib 93 fits into the inner circumferential surface of the cylindrical portion 70. This achieves radial alignment between the central axis of the motor bracket 4C (i.e., the central axis of the rotor shaft 63) and the central axis of the gear case 4A (i.e., the central axis of the reduction mechanism 30).

[0168] The second mating surface 91 is formed between each fitting rib 93 and the outer edge of the motor bracket 4C. The second mating surface 91 surrounds the outer circumference of each fitting rib 93. The second mating surface 91 is provided with a through hole 94 for the screw 4R. The second mating surface 91 is a flat surface, and each position on the surface of the second mating surface 91 is the same position in the front-rear direction.

[0169] As shown in Figure 27, when the motor bracket 4C is attached to the rear end face of the gear case 4A, the first mating surface 73 and the second mating surface 91 come into contact in the front-rear direction. In Figure 27, the outer edge of the contact area 95 between the second mating surface 91 and the first mating surface 73 is enclosed by a dotted line and shown with hatching. In the contact area 95, the flat surfaces make surface contact. The axial force of the screw 4R causes the first mating surface 73 and the second mating surface 91 to come into close contact. This prevents lubricants such as grease applied to each gear of the reduction mechanism 30 from leaking out of the inside of the gear case 4A.

[0170] [effect] As described above, in this embodiment, the power tool 1 includes a motor 6, an output unit 8 provided in front of the motor 6 and driven by the motor 6, a variable-speed reduction mechanism 30 positioned between the motor 6 and the output unit 8, a cylindrical portion 70 having a radial through hole 4J, a plurality of bracket boss portions 71 provided on the outer circumference of the cylindrical portion 70, a gear case 4A housing the reduction mechanism 30 inside the cylindrical portion 70, a motor bracket 4C positioned between the motor 6 and the reduction mechanism 30 and fixed to the plurality of bracket boss portions 71 with screws 4R, a speed switching lever 12 (switching operation unit) that switches the speed of the reduction mechanism 30 by moving, and a switching wire 50 that passes through the through hole 4J of the gear case 4A and connects the speed switching lever 12 and the reduction mechanism 30. The switching wire 50 includes, when viewed from the axial direction, a first portion 51 extending from the speed switching lever 12 to the cylindrical portion 70, a second portion 52 extending circumferentially from the end of the first portion 51 along the outer circumferential surface 70A of the cylindrical portion 70, and a third portion 53 inserted from the end of the second portion 52 into the through hole 4J. Multiple bracket boss portions 71 are provided on the outer circumference of the cylindrical portion 70 at positions other than the first region G1 which is radially opposite to the second portion 52.

[0171] In the above configuration, the multiple bracket bosses 71 of the gear case 4A are provided at positions other than the first region G1 on the outer circumference of the cylindrical portion 70 that is radially opposite to the second portion 52. If the bracket bosses 71 were located in the first region G1, the second portion 52 of the switching wire 50 would have to bypass the outside of the bracket bosses 71. In contrast, in this configuration, the second portion 52 of the switching wire 50 can connect the first portion 51 and the third portion 53 without bypassing the outside of the bracket bosses 71. This shortens the path length of the switching wire 50 to the reduction mechanism 30, thus increasing the spring constant (rigidity) of the switching wire 50. With a higher spring constant, even if a reaction force acts on the gear connected by the switching wire 50, the switching wire 50 is less likely to bend and can support the gear. As a result, misalignment of the gears for speed change in the reduction mechanism 30 is less likely to occur, allowing for more reliable speed changeovers.

[0172] In this embodiment, the gear case 4A has through holes 4J on one and the other lateral sides. The switching wire 50 includes a one-way wire portion 50R having a first portion 51, a second portion 52, and a third portion 53, which is inserted through the through hole 4J on one side, and a other-way wire portion 50L having a first portion 51, a second portion 52, and a third portion 53, which is inserted through the through hole 4J on the other side. The plurality of bracket boss portions 71 include a first boss 71A positioned between the first portion 51 of the one-way wire portion 50R and the first portion 51 of the other-way wire portion 50L.

[0173] In the above configuration, the space between one wire section 50R and the other wire section 50L can be used to position the first boss 71A of the bracket boss section 71. This allows for the shortening of the path length of the switching wire 50 while securing installation space for the bracket boss section 71 (first boss 71A) without increasing the dimensions of the gear case 4A or motor bracket 4C.

[0174] In this embodiment, the speed switching lever 12 is positioned above the gear case 4A. The multiple bracket bosses 71 include a second boss 71B located in a second region G2 on the outer circumference of the cylindrical portion 70, which is below the through hole 4J.

[0175] In the above configuration, by positioning the second boss 71B in the second region G2 below the through hole 4J in the gear case 4A where the switching wire 50 is not located, the number of fixing points for the motor bracket 4C can be increased without rerouting the path of the switching wire 50. The first boss 71A and the second boss 71B firmly fix the gear case 4A and the motor bracket 4C, which helps to suppress issues such as lubricant (grease) leakage.

[0176] In this embodiment, the second boss 71B is positioned on one side and the other side of the cylindrical portion 70 within the second region G2.

[0177] In the above configuration, by placing multiple second bosses 71B in the second region G2 of the gear case 4A where the switching wire 50 is not located, the fixing points of the motor bracket 4C to the gear case 4A can be distributed over a wide area in the circumferential direction. As a result, the motor bracket 4C can be fixed more evenly by the first boss 71A and the multiple second bosses 71B. Even in this case, the switching wire 50 does not need to detour around the outside of each boss, thereby improving the reliability of gear shifting.

[0178] In this embodiment, the radial distance CL between the second portion 52 of the switching wire 50 and the outer circumferential surface 70A of the first region G1 of the cylindrical portion 70 is smaller than the amount EP of the bracket boss portion 71 protruding from the outer circumferential surface 70A of the first region G1.

[0179] In the above configuration, the second portion 52 of the switching wire 50 is positioned radially inward from the outer circumference of the bracket boss portion 71, and the gap CL between it and the outer surface 70A of the cylindrical portion 70 of the gear case 4A becomes sufficiently small. As a result, the path length of the second portion 52 of the switching wire 50 can be effectively shortened, thereby effectively increasing the spring constant of the switching wire 50 and further improving the performance of holding the position of the gear for shifting.

[0180] In one embodiment, the gear case 4A is further provided with a gear housing 4B located in front of it, to which the front end of the gear case 4A is fixed. The gear case 4A is located radially outward from the switching wire 50 and includes a plurality of housing bosses 72 which are fixed to the gear housing 4B with screws 4Q.

[0181] In the above configuration, the gear case 4A can be fixed to the gear housing 4B by multiple housing bosses 72, separate from the bracket boss 71. Even in this case, since the multiple housing bosses 72 are positioned radially outside the switching wire 50, the switching wire 50 does not need to detour around the outside of the housing bosses 72, thus avoiding an increase in the path length of the switching wire 50.

[0182] In this embodiment, the multiple housing bosses 72 include a third boss 72A that is positioned radially outward from the second portion 52 of the switching wire 50 in the first region G1.

[0183] In the above configuration, in the first region G1 where the bracket boss portion 71 is not located, space for the housing boss portion 72 (third boss 72A) can be secured without having to reroute the second portion 52 of the switching wire 50.

[0184] In this embodiment, the third boss 72A has a notch 72C on its outer circumference facing the radial center of the cylindrical portion 70 that allows the switching wire 50 to pass through.

[0185] In the above configuration, by providing a notch 72C in the third boss 72A, which is positioned radially outward from the second portion 52 of the switching wire 50, the radial position of the third boss 72A can be brought closer to the second portion 52. This makes it possible to suppress an increase in the external dimensions of the gear case 4A even when the third boss 72A is positioned outside the second portion 52 of the switching wire 50.

[0186] In this embodiment, the gear case 4A has through holes 4J on one and the other side. The switching wire 50 includes a one-way wire portion 50R having a first portion 51, a second portion 52, and a third portion 53, which is inserted through the through hole 4J on one side, and a other-way wire portion 50L having a first portion 51, a second portion 52, and a third portion 53, which is inserted through the through hole 4J on the other side. The third boss 72A is positioned outside the second portion 52 of the one-way wire portion 50R and outside the second portion 52 of the other-way wire portion 50L, respectively.

[0187] In the above configuration, by positioning the third boss 72A on the outside of the second portion 52 of the wire section 50R and the outside of the second portion 52 of the wire section 50L, the fixing points between the gear case 4A and the gear housing 4B can be distributed over a wide area. This allows the gear case 4A to be fixed more evenly.

[0188] In this embodiment, the speed switching lever 12 is positioned above the gear case 4A. The multiple housing bosses 72 include a fourth boss 72B located in a second region G2 below the through hole 4J on the outer circumference of the cylindrical portion 70.

[0189] In the above configuration, by positioning the fourth boss 72B in the second region G2 of the gear case 4A where the switching wire 50 is not located, the fixing points of the gear case 4A to the gear housing 4B can be distributed over a wide area in the circumferential direction. As a result, the gear case 4A can be fixed more evenly by the third boss 72A and the fourth boss 72B.

[0190] In this embodiment, the power tool 1 includes a motor 6, an output unit 8 located in front of the motor 6 and driven by the motor 6, a variable-speed reduction mechanism 30 positioned between the motor 6 and the output unit 8, a gear case 4A including a cylindrical portion 70 having a radial through hole 4J and housing the reduction mechanism 30 inside the cylindrical portion 70, a motor bracket 4C positioned between the motor 6 and the reduction mechanism 30 and fixed to the gear case 4A with a screw 4R, a speed switching lever 12 (switching operation unit) that switches the speed of the reduction mechanism 30 by moving, and a switching wire 50 that passes through the through hole 4J of the gear case 4A and connects the speed switching lever 12 and the reduction mechanism 30. The switching wire 50 includes a held portion 50F that is held by the speed switching lever 12. The gear case 4A includes a first screw fixing portion 75 that fixes the motor bracket 4C at a position facing radially from the held portion 50F of the switching wire 50 when viewed from the axial direction.

[0191] In the above configuration, the first screw fixing portion 75 that secures the motor bracket 4C is positioned in the gear case 4A, facing radially from the held portion 50F of the switching wire 50 when viewed from the axial direction. If the first screw fixing portion 75 were located in the middle of the path to the reduction mechanism 30, the switching wire 50 would have to detour around the outside of the first screw fixing portion 75. In contrast, in this configuration, the switching wire 50 can be connected to the connection point with the reduction mechanism 30 without detouring around the outside of the held portion 50F and the first screw fixing portion 75. This shortens the path length of the switching wire 50 to the reduction mechanism 30, thus increasing the spring constant (rigidity) of the switching wire 50. With a higher spring constant of the switching wire 50, even if a reaction force acts on the gear connected by the switching wire 50, the switching wire 50 is less likely to bend and can support the gear. As a result, misalignment of the gears for speed change in the reduction mechanism 30 is less likely to occur, allowing for more reliable speed change.

[0192] In this embodiment, in the gear case 4A, one first screw fixing portion 75 is provided in the opposing region GF that faces the switching wire 50 radially when viewed from the axial direction. In the non-opposing region (second region G2) of the gear case 4A that does not face the switching wire 50 radially when viewed from the axial direction, a plurality of second screw fixing portions 76 for fixing the motor bracket 4C are provided.

[0193] In the above configuration, since only one first screw fixing part 75 is provided in the opposing region GF, the switching wire 50 does not need to bypass the screw fixing part. Since multiple second screw fixing parts 76 are provided in the non-opposing region, the motor bracket 4C and the gear case 4A can be evenly fixed at multiple points while avoiding increasing the path length of the switching wire 50.

[0194] In this embodiment, the gear case 4A is fixed to the motor bracket 4C at three points arranged in a triangular shape when viewed from the axial direction, by one first screw fixing portion 75 located in the opposing region GF and two second screw fixing portions 76 located on one side and the other side relative to the center of the gear case 4A in the non-opposing region (second region G2).

[0195] In the above configuration, the motor bracket 4C and the gear case 4A are fixed at three points arranged in a triangular shape when viewed from the axial direction, thereby avoiding increasing the path length of the switching wire 50 while evenly and firmly fixing the motor bracket 4C and the gear case 4A.

[0196] In this embodiment, the gear case 4A has a circumferentially flat first mating surface 73 on its rear end face facing the motor bracket 4C. The motor bracket 4C has a circumferentially flat second mating surface 91 on its front surface 90 facing the gear case 4A, which abuts against the first mating surface 73.

[0197] In the above configuration, the first mating surface 73 of the gear case 4A and the second mating surface 91 of the motor bracket 4C can be brought into flat surface contact with each other. This effectively suppresses leakage of lubricant (grease) inside the gear case 4A even when vibrations occur due to the operation of the motor 6.

[0198] In one embodiment, the gear case 4A is further provided with a gear housing 4B located in front of it, to which the front end of the gear case 4A is fixed. The gear case 4A includes two third screw fixing portions 77, which are positioned in the circumferential direction between a first screw fixing portion 75 and a second screw fixing portion 76 on one side, and between the first screw fixing portion 75 and the second screw fixing portion 76 on the other side.

[0199] In the above configuration, the screw fastening points between the gear case 4A and the gear housing 4B (third screw fastening point 77) can be positioned circumferentially offset from the screw fastening points between the gear case 4A and the motor bracket 4C (first screw fastening point 75, second screw fastening point 76). This improves the workability of each screw fastening operation.

[0200] In this embodiment, the gear case 4A includes a fourth screw fixing portion 78 positioned between two second screw fixing portions 76 on one side and the other side in a non-facing region (second region G2). The gear case 4A is fixed to the gear housing 4B at three locations arranged in an inverted triangular shape when viewed from the axial direction by two third screw fixing portions 77 and one fourth screw fixing portion 78.

[0201] In the above configuration, the motor bracket 4C and the gear case 4A are fixed at three points arranged in a triangular shape when viewed from the axial direction, and the gear case 4A and the gear housing 4B are fixed at three points arranged in an inverted triangular shape when viewed from the axial direction. This allows for even fixing of the motor bracket 4C and the gear case 4A, and the gear case 4A and the gear housing 4B, while improving the workability of the screw tightening work for each.

[0202] [Other embodiments] In the above-described embodiment, a battery pack 20 mounted in the battery mounting section 5 is used as the power source for the power tool 1. However, commercial power (AC power) may also be used as the power source for the power tool 1.

[0203] In the embodiments described above, an example was shown where the power tool 1 is a vibration driver drill, but the power tool may be a power tool other than a vibration driver drill. The power tool is not particularly limited as long as it has a reduction mechanism with a variable speed function and a structure in which the switching operation part and the reduction mechanism are connected by a switching wire.

[0204] In the above-described embodiment, an example was shown in which three bracket boss portions 71 are provided, but two or four or more bracket boss portions 71 may be provided. In the above-described embodiment, an example was shown in which three housing boss portions 72 are provided, but two or four or more housing boss portions 72 may be provided.

[0205] [Note] The technology disclosed herein may have the following configuration: [Note A] Motor and, An output unit is provided in front of the motor and is driven by the motor, A reduction mechanism is disposed between the motor and the output unit, A gear case housing the reduction mechanism, The motor bracket is positioned between the motor and the reduction mechanism and fixed to the gear case, The gear case has a circumferential flat first mating surface at its rear end face facing the motor bracket, The motor bracket has a circumferentially flat second mating surface on its front surface facing the gear case, which contacts the first mating surface. Power tools.

[0206] In the power tools relating to the configuration of Appendix A, the reduction mechanism does not need to have a speed change function, and therefore does not need to have a switching operation unit or a switching wire. [Explanation of symbols]

[0207] 1…Power tool, 2…Housing, 2A…Opening, 2G…Guide surface, 2H…Engaging recess, 2L…Left housing, 2R…Right housing, 2S…Screw, 3…Rear cover, 3S…Screw, 4…Casing, 4A…Gear case, 4B…Gear housing, 4C…Motor bracket, 4D…Stop plate, 4F…Screw, 4G…Recess, 4H…Screw hole, 4J…Through hole, 4Q…Screw, 4R…Screw, 4S…Screw, 5…Battery mounting section, 6…Motor, 7…Power transmission mechanism, 8…Output section, 9…Fan, 10…Trigger lever, 11…Forward / reverse rotation switch lever, 12…Speed ​​switch lever (switching operation section), 1 2A...Knob part, 12B...Leaf spring, 12C...Protrusion part, 12L...Retaining leg part, 12T...Retaining groove, 13...Mode switching ring, 14...Light, 17...Controller, 18...Air intake, 19...Exhaust port, 20...Battery pack, 21...Motor housing part, 22...Grip part, 23...Battery holder part, 26...Controller case, 30...Reduction mechanism, 31...First planetary gear mechanism, 31A...First pin, 31C...First carrier, 31K...External gear, 31P...Planetary gear, 31R...Internal gear, 31S...Pinion gear, 32...Second planetary gear mechanism, 32A...Pin, 32C...Second key Carrier, 32E…groove, 32F…cam tooth, 32P…planetary gear, 32R…internal gear, 32S…sun gear, 33…third planetary gear mechanism, 33A…pin, 33C…third carrier, 33P…planetary gear, 33R…internal gear, 33S…sun gear, 34…engaging member, 34A…projection, 35…engaging projection, 36…speed switching mechanism, 37…locking ring, 37A…projection, 37B…cam tooth, 40…vibration mechanism, 41…first cam, 42…second cam, 43…vibration switching ring, 43C…switching cam, 43E…spring, 43S…opposing part, 44…stop ring, 45…support Ring, 46...Steel ball, 47...Washer, 48...Cam ring, 50...Switching wire, 50F...Holded part, 50L...Other wire part, 50R...One wire part, 51...First part, 52...Second part, 53...Third part, 54...Connecting part, 61...Stator, 61A...Stator core, 61B...Front insulator, 61C...Rear insulator, 61D...Coil, 61E...Sensor circuit board, 61F...Short-circuiting member, 62...Rotor, 62A...Rotor core, 62B...Permanent magnet, 63...Rotor shaft, 64...Bearing, 65...Bearing, 70...Cylindrical part, 70A...Outer circumference,70B...regulating rib, 71...bracket boss, 71A...first boss, 71B...second boss, 71H...thread hole, 72...housing boss, 72A...third boss, 72B...fourth boss, 72C...notch, 72H...through hole, 73...first mating surface, 74...flange, 75...first screw fixing part, 76...second screw fixing part, 77...third screw fixing part, 78...fourth screw fixing part, 81...spindle 81F…Flange section, 81R…Screw hole, 82…Chuck, 83…Bearing, 84…Bearing, 87…Coil spring, 90…Front surface, 91…Second mating surface, 92…Opening, 93…Matching rib, 94…Through hole, 95…Contact area, CL…Spacing, DP…Design position, EP…Protrusion amount, G1…First area, G2…Second area, G3…Third area, GF…Opposite area, R1…Radius, R2…Radius.

Claims

1. Motor and, An output unit is provided in front of the motor and is driven by the motor, A variable-speed reduction mechanism is disposed between the motor and the output unit, A gear case comprising a cylindrical portion having a radial through hole, and a plurality of bracket boss portions provided on the outer circumference of the cylindrical portion, with the reduction mechanism housed inside the cylindrical portion, A motor bracket is positioned between the motor and the reduction mechanism and is fixed to the plurality of bracket bosses with screws, A switching operation unit that performs a speed change for the reduction mechanism by moving, The gear case includes a switching wire that passes through the through hole and connects the switching operation unit and the reduction mechanism, The switching wire includes, when viewed from the axial direction, a first portion extending from the switching operation part to the cylindrical portion, a second portion extending circumferentially from the end of the first portion along the outer surface of the cylindrical portion, and a third portion inserted through the through hole from the end of the second portion. The plurality of bracket bosses are provided on the outer circumference of the cylindrical portion at positions other than the first region which is radially opposite to the second portion. Power tools.

2. The gear case has the through holes on one and the other side, respectively. The switching wire includes a first portion, a second portion, and a third portion, which is inserted into the through hole on one side, and a second portion, which is inserted into the through hole on the other side. The plurality of bracket bosses include a first boss positioned between the first portion of one wire section and the first portion of the other wire section. The power tool according to claim 1.

3. The switching operation unit is positioned above the gear case, The plurality of bracket bosses include a second boss positioned in a second region on the outer circumference of the cylindrical portion that is below the through hole. The power tool according to claim 2.

4. The second boss is positioned on one side and the other side of the cylindrical portion within the second region. The power tool according to claim 3.

5. The radial distance between the second portion of the switching wire and the outer circumferential surface of the first region of the cylindrical portion is smaller than the amount of protrusion of the bracket boss portion relative to the outer circumferential surface of the first region. The power tool according to any one of claims 1 to 4.

6. The gear case is further provided with a gear housing located in front of the gear case, to which the front end of the gear case is fixed. The gear case is positioned radially outward from the switching wire and includes a plurality of housing bosses that are screwed to the gear housing. The power tool according to claim 1.

7. The plurality of housing bosses include a third boss that is positioned radially outward from the second portion of the switching wire in the first region. The power tool according to claim 6.

8. The third boss has a notch on its outer circumference facing the radial center of the cylindrical portion that allows the switching wire to pass through. The power tool according to claim 7.

9. The gear case has the through holes on one and the other side, respectively. The switching wire includes a first portion, a second portion, and a third portion, which is inserted into the through hole on one side, and a second portion, which is inserted into the through hole on the other side. The third boss is positioned on the outside of the second portion of the one wire section and on the outside of the second portion of the other wire section, respectively. The power tool according to claim 7.

10. The switching operation unit is positioned above the gear case, The plurality of housing bosses include a fourth boss located in a second region on the outer circumference of the cylindrical portion that is below the through hole. The power tool according to claim 7.

11. Motor and, An output unit is provided in front of the motor and is driven by the motor, A variable-speed reduction mechanism is disposed between the motor and the output unit, A gear case comprising a cylindrical portion having a radial through hole, the reduction mechanism being housed inside the cylindrical portion, A motor bracket is positioned between the motor and the reduction mechanism and fixed to the gear case with screws, A switching operation unit that performs a speed change for the reduction mechanism by moving, The gear case includes a switching wire that passes through the through hole and connects the switching operation unit and the reduction mechanism, The switching wire includes a portion that is held by the switching operation unit, The gear case includes a first screw fixing portion for fixing the motor bracket at a position facing radially from the portion of the switching wire that is held when viewed from the axial direction. Power tools.

12. In the gear case, in the region facing the switching wire in the radial direction when viewed from the axial direction, one of the first screw fixing portions is provided. In the gear case, in a non-facing region that does not face the switching wire radially when viewed from the axial direction, a plurality of second screw fixing portions for fixing the motor bracket are provided. The power tool according to claim 11.

13. The gear case is fixed to the motor bracket at three points arranged in a triangular shape when viewed from the axial direction, by one first screw fixing portion located in the opposing region and two second screw fixing portions located on one and the other lateral sides of the center of the gear case in the non-opposing region. The power tool according to claim 12.

14. The gear case has a circumferential flat first mating surface at its rear end face facing the motor bracket. The motor bracket has a circumferentially flat second mating surface on its front surface facing the gear case, which contacts the first mating surface. The power tool according to claim 11.

15. The gear case is further provided with a gear housing located in front of the gear case, to which the front end of the gear case is fixed. The gear case includes two third screw fixing portions, which are positioned in the circumferential direction between the first screw fixing portion and one of the second screw fixing portions, and between the first screw fixing portion and the other of the second screw fixing portions. The power tool according to claim 13.

16. The gear case is, The non-facing region includes a fourth screw fixing portion positioned between the two second screw fixing portions on one side and the other side, The gear housing is fixed at three points arranged in an inverted triangular shape when viewed from the axial direction, by the two third screw fixing points and the one fourth screw fixing point. The power tool according to claim 15.

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