Power tool

Abstract

To lock, with high reliability, an operating member at a neutral position of a brush holding member.SOLUTION: A hammer drill 1 includes: a motor 4 including a stator 13 and a rotor 14 having a commutator 15 and a rotary shaft 16; a brush base 67 that holds a pair of carbon brushes abutting on the commutator 15 and is capable of switching, with the commutator 15 as a center, a rotational position to a normal position, a reverse position, and a neutral position between the normal position and the reverse position; a switch 6 that turns ON / OFF the motor 4; a trigger 44 that turns ON the switch 6 by a pushing operation; and a lock lever 90 a front end 93 of which is disposed on an outer side of the brush base 67 in a radial direction of the rotor 14 and a rear end 94 of which is engageable with and disengageable from the trigger 44. When the front end 93 abuts on an outer peripheral surface of the brush base 67 in the neutral position in the radial direction, the lock lever 90 is brought into a first posture in which the rear end 94 locks to the trigger 44 and restricts the pushing operation.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to power tools such as hammer drills. [Background technology]

[0002] Among electric tools such as hammer drills, there are known AC machines using brushed motors that can switch the rotation of the rotor of the motor between forward and reverse. For example, German Patent Publication No. 102004037898 (Patent Document 1) discloses a hammer drill in which a ring-shaped brush element (brush holding member) that holds a brush that slides against a commutator provided on the rotor is rotatable to a forward rotation position, a neutral position, and a reverse rotation position, and an operating element that protrudes from a housing is provided on a switching member connected to the brush element. Here, the operating element is operated to rotate the brush element via the switching member to either the forward rotation position or the reverse rotation position, thereby switching between the forward and reverse rotation of the rotor. In addition, in the hammer drill of Patent Document 1, a switch button (operating member) that is pressed to turn on a switch that drives a motor is provided behind the switching member, and a blocking element is provided on the operating element that engages with a fixed head provided on the front end of the switch button when in the neutral position. This prevents the switch button from being pressed when the brush element is in the neutral position, preventing the motor from starting up unexpectedly. Furthermore, when the operating element is in either the forward or reverse switching position and the switch button is pressed in, the retracted fixed head interferes with the forward / reverse switching direction of the operating element, thereby preventing forward / reverse switching operation while the motor is running. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] German Patent Publication No. 102004037898 Summary of the Invention [Problem to be solved by the invention]

[0004] In power tools such as hammer drills, in order to prevent vibrations generated in the output unit from being transmitted to the operator's hands, a front housing that houses the motor and the output unit and a rear housing that houses the switch are connected so as to be movable relative to each other in the front-rear direction, and the rear housing is biased to a retracted position by an elastic member. Therefore, when an operator holding the rear housing pushes the rear housing forward, the position of the rear housing relative to the front housing is elastically maintained, providing a vibration-damping effect. However, in the hammer drill of Patent Document 1, when the brush element is in the neutral position, the operating element of the brush element and the fixed head of the switch button engage in the front-rear direction to prevent the switch button from being pressed. Therefore, if this locking mechanism for the switch button is applied to a power tool with a vibration-proof function, there is a risk that the locking mechanism for the switch button will not work if the relative movement of the front and rear housings causes the distance between the operating element of the brush element and the fixed head of the switch button to increase in the front-rear direction. This can also occur due to dimensional errors or assembly errors in the various components, such as the operating element and the fixed head.

[0005] In view of the above, an object of the present disclosure is to provide an electric power tool that can reliably lock an operating member at a neutral position of a brush holding member. [Means for solving the problem]

[0006] In order to achieve the above object, the present disclosure provides a motor including a stator and a rotor having a commutator and a rotating shaft; a brush holding member that holds a pair of carbon brushes in contact with a commutator and is switchable between a forward rotation position, a reverse rotation position, and a neutral position between the forward rotation position and the reverse rotation position, centered on the commutator; A switch to turn the motor on and off, An operating member that turns on the switch when pressed; It may also include a locking member, one end of which is arranged radially outside the brush holding member or a protrusion protruding from the brush holding member toward the operating member, and the other end of which is capable of being engaged and disengaged with the operating member. The locking member may be configured so that one end abuts against the outer peripheral surface or protrusion of the brush holding member in a radially neutral position, and the other end engages with the operating member to assume a first position that restricts the pushing operation. Effect of the Invention

[0007] According to the present disclosure, one end of the locking member abuts against the outer circumferential surface or protrusion of the brush holding member in the radial direction to restrict the pushing operation of the operating member. Therefore, even if the housing on the brush holding member side and the housing on the switch side move relative to each other due to the vibration isolation mechanism, or even if there are dimensional errors or assembly errors in each component, the abutting state between the one end and the outer circumferential surface or protrusion of the brush holding member can be maintained. Therefore, the operating member can be locked in the neutral position of the brush holding member with high reliability. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a rear perspective view of the hammer drill. [Diagram 2] FIG. 2 is a central vertical cross-sectional view of the hammer drill (with the brush base in the neutral position). [Diagram 3] 3 is an enlarged view of a forward / reverse switching unit and a switch portion in FIG. 2. [Figure 4] FIG. 4 is an enlarged cross-sectional view taken along line AA in FIG. [Diagram 5] FIG. 4 is an enlarged cross-sectional view taken along line BB in FIG. [Figure 6] FIG. 4 is an exploded perspective view of the forward / reverse switching unit and the switch portion. [Figure 7] 7A and 7B are partial cross-sectional views showing a state of the lock lever before the trigger is pressed when the brush base is in the normal rotation position, with FIG. 7A showing a vertical cross section and FIG. 7B showing a horizontal cross section. [Figure 8] 11 is a partial vertical cross-sectional view showing the state of the lock lever when the trigger is pressed with the brush base in the normal rotation position. FIG. [Figure 9] 13 is a partial vertical cross-sectional view showing a modified example of the biasing means of the lock lever. FIG. [Figure 10] 10A and 10B are partial cross-sectional views showing a modified example of the biasing means of the lock lever, with FIG. 10A showing a longitudinal cross-section and FIG. 10B showing a cross-section taken along line CC. [Figure 11] 13 is an enlarged view of a forward / reverse switching unit and a switch portion, showing a modified example of a brush base and a lock lever. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In one embodiment of the present disclosure, the locking member may be in a second position in which, when the brush holding member is in the forward rotation position or the reverse rotation position, the locking member releases the engagement of the other end with the operating member and allows the operating member to be pushed in. According to this configuration, once the brush holding member is switched to the forward rotation position or the reverse rotation position, the operating member can be pushed in and the switch turned ON without any hindrance. In one embodiment of the present disclosure, the locking member may be supported so that one end and the other end are each swingable around the intermediate portion, and a protrusion may be provided on the outer circumferential surface of the brush holding member for pushing up the one end of the locking member radially outward when in a neutral position. In addition, when the one end is pushed up, the other end swings to the opposite side and engages with the operating member to assume the first position. According to this configuration, the rocking movement of the locking member can be utilized to easily regulate the pushing operation of the operating member. In one embodiment of the present disclosure, the fulcrum may be set in a direction perpendicular to a plane including the axis of the rotation shaft. According to this configuration, the locking member can be disposed in a well-balanced manner relative to the brush holding member.

[0010] In one embodiment of the present disclosure, when the operating member is pushed in when the brush holding member is in the forward or reverse rotation position, the operating member restricts the swinging of the other end toward the operating member to maintain the locking member in the second position, while one end restricts the rotation of the brush holding member by interfering with a protrusion in the rotation direction of the brush holding member. According to this configuration, it is possible to reliably regulate the switching of the forward and reverse directions caused by the rotational operation of the brush holding member while the motor is being driven. In one embodiment of the present disclosure, a restricting means may be provided that restricts contact between the one end of the locking member and the outer circumferential surface of the brush holding member when the locking member is in the second position. According to this configuration, it is possible to prevent wear caused by unnecessary sliding contact between the one end and the brush holding member. In one embodiment of the present disclosure, the protrusion may be tapered such that the width in the rotational direction gradually decreases radially outward when viewed from the axial direction of the rotating shaft. According to this configuration, one end of the brush holder can smoothly ride up onto the projection as the brush holder rotates. In one embodiment of the present disclosure, the one end may be tapered such that the width in the rotational direction gradually decreases toward the radially inner side when viewed from the axial direction of the rotating shaft. With this configuration, the one end of the brush holder can ride up onto the projection more smoothly as the brush holder rotates.

[0011] In one embodiment of the present disclosure, biasing means may be provided for biasing the locking member towards the first position. According to this configuration, when the brush holding member is switched from the neutral position to the forward rotation position or the reverse rotation position, the locking member automatically goes to the second position, allowing the operating member to be pushed in. In one embodiment of the present disclosure, the biasing means may be a coil spring. According to this configuration, the biasing means can be easily formed. In one embodiment of the present disclosure, the biasing means may be a torsion spring mounted on a fulcrum. According to this configuration, the biasing means can be easily formed. In one embodiment of the present disclosure, the biasing means may be a leaf spring. According to this configuration, the biasing means can be easily formed.

[0012] In one embodiment of the present disclosure, the electric tool has a first housing that houses an output section with a final output shaft facing forward and a motor and to which a brush holding member is attached, and a second housing at the rear of the first housing that houses a switch and a locking member, the motor is housed in the first housing in a position with the rotating shaft facing in the fore-and-aft direction, the brush holding member is located at the rear of the motor, the switch is located on the rear axis of the rotating shaft within a handle section provided in the second housing and extending in the up-and-down direction, causing the operating member to protrude forward, and the locking member extends in the fore-and-aft direction at the top of the second housing, with one front end located above the brush holding member and the other rear end located above the operating member. According to this configuration, the locking member can be installed in a space-saving manner. In one embodiment of the present disclosure, the first housing and the second housing may be movable relative to each other in the forward / backward direction, and an anti-vibration mechanism including an elastic member may be interposed between the first housing and the second housing. This configuration can reduce vibrations transmitted to the hands of an operator holding the handle. In one embodiment of the present disclosure, an operating protrusion for switching the rotational position of the brush holding member may protrude upward through a window formed in the upper surface of the second housing. According to this configuration, the rotational position of the brush holding member can be easily changed. EXAMPLES

[0013] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a rear perspective view of a hammer drill, which is an example of a power tool, and FIG. 2 is a central vertical sectional view of the hammer drill. The hammer drill 1 has a front housing 2 and a rear housing 3. The front housing 2 is provided with a motor 4 and an output unit 5. The rear housing 3 is provided with a switch 6. The front housing 2 and the rear housing 3 are capable of relative movement in the front-to-rear direction. A vibration isolation mechanism 7, which will be described later, is provided between the front housing 2 and the rear housing 3. The front housing 2 is an example of a first housing of the present disclosure. The rear housing 3 is an example of a second housing of the present disclosure.

[0014] The front housing 2 includes a motor housing 8, an outer housing 9, and an inner housing 10. The motor housing 8 includes a front connecting portion 11 and a rear motor accommodating portion 12. The connecting portion 11 is in the shape of a rectangular tube, and is screwed to the outer housing 9. The motor accommodating portion 12 is in the shape of a cylinder with a smaller diameter than the connecting portion 11, and accommodates the motor 4 inside. The motor 4 has a stator 13 and a rotor 14. The rotor 14 is equipped with a commutator 15 and a rotating shaft 16. The motor 4 is accommodated in the motor accommodating section 12 with the rotating shaft 16 facing in the front-rear direction. The rotating shaft 16 penetrates the connecting section 11 and protrudes into the inner housing 10.

[0015] The outer housing 9 has a front tubular portion 17 and a rear tubular portion 18. The front tubular portion 17 is tubular with a circular cross section that extends forward. The rear tubular portion 18 is tubular with a larger diameter than the front tubular portion 17. The connecting portion 11 of the motor housing 8 is connected to the rear tubular portion 18. The front tubular portion 17 is disposed at an eccentric position above the rear tubular portion 18. A side handle 19 can be attached to the front tubular portion 17. The output section 5 has a tool holder 20, a piston cylinder 21, a striker 22, and an impact bolt 23. The tool holder 20 is cylindrical, coaxially accommodated in the front cylindrical section 17, and rotatably held by the front cylindrical section 17 and the inner housing 10. The front end of the tool holder 20 protrudes forward from the front cylindrical section 17. An operation sleeve 24 is provided at the front end of the tool holder 20. The operation sleeve 24 is provided for attaching and detaching the bit B at the front end of the tool holder 20. A gear 25 is externally mounted on the tool holder 20 within the rear cylindrical section 18. The tool holder 20 is an example of a final output shaft of the present disclosure.

[0016] The piston cylinder 21 is open at its front end and is housed in the rear of the tool holder 20 so as to be movable back and forth. The striker 22 is housed in the piston cylinder 21 so as to be movable back and forth via an air chamber 26. The impact bolt 23 is housed in the tool holder 20 in front of the striker 22 so as to be movable back and forth. In the output portion 5, an intermediate shaft 27 parallel to the tool holder 20 is rotatably provided below the tool holder 20. The rotating shaft 16 has a pinion 28 formed at its front end protruding above the intermediate shaft 27. The intermediate shaft 27 is provided at its rear with a first gear 29 that meshes with the pinion 28 and is capable of rotating integrally with the intermediate shaft 27. The intermediate shaft 27 is provided at its front with a second gear 30 that is capable of rotating separately. The second gear 30 meshes with the gear 25 of the tool holder 20. A boss sleeve 31 is separately and rotatably mounted on the intermediate shaft 27 in front of the first gear 29. An arm 33 is held facing upward by the boss sleeve 31 via a swash bearing 32 whose axis is inclined. The tip of the arm 33 is connected to the rear end of the piston cylinder 21.

[0017] Two first and second clutches 34, 35 are splined between the boss sleeve 31 and the second gear 30. The first clutch 34 engages with the boss sleeve 31 in the retracted position. Therefore, the rotation of the intermediate shaft 27 is transmitted to the boss sleeve 31 via the first clutch 34. When the first clutch 34 advances and separates from the boss sleeve 31, the rotation of the intermediate shaft 27 is no longer transmitted to the boss sleeve 31. The second clutch 35 engages with the second gear 30 in the forward position. Therefore, the rotation of the intermediate shaft 27 is transmitted to the second gear 30 via the second clutch 35, and is further transmitted to the gear 25 and the tool holder 20. When the second clutch 35 retracts and moves away from the second gear 30, the rotation of the intermediate shaft 27 is no longer transmitted to the second gear 30 and the tool holder 20.

[0018] Two plates 36, 36 that engage with both clutches 34, 35 are provided below the intermediate shaft 27 so as to be movable back and forth. The position of each plate 36 can be changed by a switching knob 37. The switching knob 37 is provided on the underside of the rear cylindrical portion 18 so as to be rotatable. The switching knob 37 has two eccentric pins (not shown) that protrude upward. The eccentric pins engage with each of the plates 36. Therefore, the front-rear position of each plate 36 can be switched via the eccentric pin by rotating the switching knob 37. In other words, by switching the front-rear positions of the first and second clutches 34, 35, the drill mode, hammer drill mode, neutral, and hammer mode can be selected.

[0019] In the drill mode, the first clutch 34 is in the forward position, and the second clutch 35 is in the forward position. Therefore, the tool holder 20 rotates via the intermediate shaft 27, rotating the bit B at the tip. Since the boss sleeve 31 does not rotate, no impact action occurs. In the hammer drill mode, the first clutch 34 is in the backward position, and the second clutch 35 is in the forward position. Therefore, the tool holder 20 rotates via the intermediate shaft 27, and the boss sleeve 31 rotates, causing the arm 33 to swing back and forth, and the piston cylinder 21 reciprocates. Then, the striker 22 reciprocates to strike the bit B via the impact bolt 23. In the hammer mode, the first clutch 34 is in the retracted position, and the second clutch 35 is in the retracted position. Therefore, the boss sleeve 31 rotates via the intermediate shaft 27, and the bit B is struck by the striker 22 via the impact bolt 23. The tool holder 20 does not rotate. When the switching knob 37 is switched to neutral, a lock ring (not shown) that was engaged with the second gear 30 in the hammer mode is separated from the second gear 30. Therefore, the tool holder 20 together with the second gear 30 becomes free to rotate, and the bit B can be adjusted to any angle around the axis.

[0020] The rear housing 3 is composed of a pair of half housings 3a and 3b on the left and right. The half housings 3a and 3b are assembled by a plurality of screws screwed in from the right side. The rear housing 3 has an outer cylinder portion 40 on the front side that covers the motor housing portion 12 from the rear. The front end of the outer cylinder portion 40 has the same outer shape as the connecting portion 11 of the motor housing 8. A handle portion 41 extending in the vertical direction is integrally formed on the rear side of the outer cylinder portion 40. The handle portion 41 is connected to the outer cylinder portion 40 in a loop shape by an upper connection portion 42 extending rearward from the upper portion of the outer cylinder portion 40 and a lower connection portion 43 extending obliquely downward rearward from the lower portion of the outer cylinder portion 40. The switch 6 is accommodated in the upper portion of the handle portion 41 on the rear axis line of the rotating shaft 16, and a trigger 44 protrudes forward through an opening 41a formed from the front surface to the upper surface of the handle portion 41. The trigger 44 is an example of an operating member of the present disclosure. A power cord 45 is connected to the switch 6. The power cord 45 is pulled out from the lower end of the handle portion 41. A plurality of air intake ports 46, 46... are formed on the left and right sides of the rear surface of the outer cylinder portion 40. A fan 47 is attached to the rotating shaft 16 inside the connecting portion 11. A plurality of air exhaust ports 48, 48 are formed on the underside of the connecting portion 11. When the fan 47 rotates together with the rotating shaft 16, outside air is sucked in through the air intake port 46 and passes through the outer cylinder portion 40 and the motor accommodating portion 12, and is exhausted from the air exhaust port 48. This cools the forward / reverse switching unit 65 and the motor 4, which will be described later.

[0021] The vibration isolation mechanism 7 includes a rubber sleeve 50 and a coil spring 51 . The rubber sleeve 50 is interposed between the connecting portion 11 of the motor housing 8 and the outer tubular portion 40 of the rear housing 3. The rubber sleeve 50 is a bellows-shaped rectangular tube, with its front end engaging with the rear end surface of the connecting portion 11 and its rear end engaging with the front end surface of the outer tubular portion 40. The rubber sleeve 50 closes the gap between the front housing 2 and the rear housing 3 over the entire circumference, and expands and contracts in the axial direction in accordance with the relative movement of the two housings 2, 3 forward and backward. The coil spring 51 is interposed between the motor accommodating portion 12 and the outer cylinder portion 40 inside the rear housing 3. One coil spring 51 is arranged on the upper side of the motor accommodating portion 12, and two coil springs 51 are arranged on the left and right sides on the lower side of the motor accommodating portion 12. A front receiving plate 52 extending in the left-right direction is erected on the upper surface of the motor accommodating portion 12. A rear receiving plate 53 extending in the left-right direction is provided on the inner surface of the outer cylinder portion 40 behind the front receiving plate 52. The upper coil spring 51 is arranged in the front-rear direction between the front receiving plate 52 and the rear receiving plate 53.

[0022] A pair of left and right front spring bearings (not shown) are provided on the rear surface of the connecting portion 11 below the motor accommodating portion 12. A pair of left and right rear spring bearings 54, 54 are formed on the inner surface of the outer cylinder portion 40 behind each front spring bearing. The two lower coil springs 51, 51 are disposed in the front-rear direction between the front spring bearings and the rear spring bearings 54, 54. Therefore, the front housing 2 and the rear housing 3 are biased in directions away from each other by the rubber sleeve 50 and the three coil springs 51. However, in the retracted position where the rear housing 3 is separated from the front housing 2, as shown in Fig. 2, an upper stopper 55 protruding forward from the front receiving plate 52 comes into contact with a screw boss 56 protruding to the right from the left half housing 3a. Therefore, the rear housing 3 is normally biased to the retracted position shown in FIG. 2 where the upper stopper 55 and the screw boss 56 abut against each other. A plate-like portion 57 that protrudes rearward is integrally formed at the lower portion of the motor accommodating portion 12. Guide ribs 58, 58 that receive the upper and lower surfaces of the plate-like portion 57 are provided on the inner peripheral surface of the outer cylinder portion 40. Thus, the relative movement of the front housing 2 and the rear housing 3 in the front-rear direction is guided by the sliding contact between the plate-like portion 57 and the guide rib 58.

[0023] As shown in FIG. 3, a bearing holder 60 is provided on the rear side of the motor housing 12. The bearing holder 60 is smaller in diameter than the motor housing 12 and is cap-shaped with an opening at the front. The bearing holder 60 is coaxially connected to the rear surface of the motor housing 12 by upper and lower arm portions 61, 61 extending in the front-rear direction. The bearing holder 60 holds a bearing 62 on its rear inner surface and supports the rear end of the rotating shaft 16. The arm portions 61, 61 are formed in a concentric arc shape centered on the axis of the rotating shaft 16. The commutator 15 of the rotor 14 is exposed to the left and right between the arm portions 61, 61. A pair of step portions 63, 63 (FIG. 6) recessed forward from the rear surface of the bearing holder 60 are formed at the rear ends of the arm portions 61, 61, respectively.

[0024] A forward / reverse switching unit 65 is attached to the rear surface of the motor accommodating portion 12. The forward / reverse switching unit 65 includes a unit base 66 and a brush base 67. The unit base 66 is disk-shaped, and two left and right points are screwed coaxially from the rear to the motor accommodating portion 12. As shown in Figures 5 and 6, the unit base 66 is provided with a pair of fixed contacts 68, 68. The fixed contacts 68, 68 are arc-shaped when viewed from behind, and are disposed in point symmetry with respect to the axis of the unit base 66. Four terminals (not shown) are provided at the rear of the stator 13 of the motor 4, which are located at the vertices of a rectangle in rear view. The unit base 66 is provided with four connection terminals 69, 69..., which are electrically connected to the four terminals, as shown in Fig. 4. Of the four connection terminals 69, a pair of connection terminals 69, 69 located at the upper left and lower right diagonally in rear view are formed integrally with fixed contacts 68, 68. Lead wires 70, 70 are connected to the other pair of connection terminals 69, 69 located at the lower left and upper right diagonally.

[0025] The brush base 67 is coaxially and rotatably assembled to the rear surface of the unit base 66. The brush base 67 is short and cylindrical, and includes a pair of brush holders 75, 75 arranged in a diametrically symmetrical position. Each brush holder 75 accommodates a carbon brush 76. The carbon brush 76 is biased toward the axial center of the brush base 67 by a spiral spring 77 provided in the brush holder 75, and presses the commutator 15 between the arms 61, 61. The brush base 67 is an example of a brush holding member of the present disclosure. A pair of movable contacts 78, 78 are provided on the brush base 67. The movable contacts 78, 78 are integrally held on the brush base 67 via a pair of holding blocks 79, 79 attached to the brush base 67, and are electrically connected to the carbon brushes 76, 76. The movable contacts 78, 78 are positioned concentrically with the fixed contacts 68, 68 of the unit base 66, and can be brought into contact with and separated from the fixed contacts 68, 68 as the brush base 67 rotates. An operation protrusion 80 is provided on the upper peripheral surface of the brush base 67. The operation protrusion 80 protrudes radially outward from the outer peripheral surface of the brush base 67 and penetrates a window 81 provided on the upper surface of the rear housing 3 to be exposed upward. A protrusion 82 is provided on the outer peripheral surface of the brush base 67 behind the operation protrusion 80. The protrusion 82 has a tapered shape in rear view such that its width in the rotational direction gradually decreases toward the radially outer side of the brush base 67. The upper surface of the protrusion 82 where the width is narrowest is located directly behind the operation protrusion 80.

[0026] In this forward / reverse switching unit 65, the brush base 67 can be rotated from the outside via the operating protrusion 80. The rotation of the brush base 67 causes the movable contacts 78, 78 to move in contact with and away from the fixed contacts 68, 68 to switch the direction of current flow, thereby switching the direction of rotation of the rotor 14. That is, the brush base 67 can be switched between a forward rotation position where the movable contacts 78, 78 contact the fixed contacts 68, 68 in the forward rotation direction, a reverse rotation position where the movable contacts 78, 78 contact the fixed contacts 68, 68 in the reverse rotation direction, and a neutral position between the two rotation positions where the movable contacts 78, 78 do not contact the fixed contacts 68, 68. FIGS. 1 to 6 show the neutral position where the operating protrusion 80 is located in the center of the window 81. When the operating protrusion 80 is tilted to the left, it becomes the forward rotation position, and when it is tilted to the right, it becomes the reverse rotation position.

[0027] The stator 13 and the switch 6 are electrically connected by a plurality of lead wires including the lead wires 70, 70. Each lead wire is held at the rear side of the motor accommodating portion 12 via a lead wire holder 85 that is assembled to the bearing holding portion 60. The lead wire holder 85 is in the shape of a ring with an inner diameter larger than that of the bearing holding portion 60. A pair of upper and lower engaging pieces 86, 86 that respectively engage with the upper and lower step portions 63, 63 of the arms 61, 61 are formed on the inner circumference of the lead wire holder 85. A pair of fitting pieces 87, 87 that fit into and lock into the bearing holding portion 60 are formed on the lead wire holder 85. A plurality of lead wire holding portions 88, 88... are formed on the lead wire holder 85. Each lead wire is pulled downward with its middle portion engaged with the lead wire holding portion 88 and slackened, and is connected to the switch 6 from the lower portion of the handle portion 41 through the lower connection portion 43.

[0028] A lock lever 90 is provided in the rear housing 3 in a region spanning from the outer tube portion 40 to the upper connection portion 42. The lock lever 90 is a band-shaped member extending in the front-rear direction, with pins 91, 91 provided on the left and right side surfaces at the center in the front-rear direction. These pins 91, 91 are rotatably supported by receiving portions 92, 92 provided on the inner surfaces of the left and right half housings 3a, 3b. The pin 91 is set in the left-right direction perpendicular to a plane that includes the axis of the rotation shaft 16 and is defined by the front-rear and up-down directions. Therefore, the front end 93 and rear end 94 of the lock lever 90 can each swing up and down around the pins 91, 91 that serve as fulcrums. The front end 93 extends above the brush base 67 of the forward / reverse switching unit 65 and moves radially relative to the outer circumferential surface of the brush base 67. As shown in Fig. 4, the front end 93 is plate-shaped with a left-right width that is slightly smaller than the circumferential width of the protrusion 82, and is tapered so that the left-right width gradually decreases toward the inside in the radial direction of the brush base 67. In other words, it is tapered in the opposite direction to the protrusion 82. The lock lever 90 is an example of a lock member of the present disclosure. The front end portion 93 is an example of one end portion of the present disclosure. The rear end portion 94 is an example of the other end portion of the present disclosure.

[0029] A coil spring 95 is disposed behind the pin 91. The lower end of the coil spring 95 is held by a spring receiver 96 (FIG. 3) with a U-shaped cross section that is formed in the left housing half 3a and located on the lower inner surface of the upper connection portion 42. The upper end of the coil spring 95 is held by a boss 97 that faces downward on the lower surface of the lock lever 90. Therefore, the lock lever 90 is urged to rotate in the counterclockwise direction in FIG. 3, with the front end 93 directed toward the outer circumferential surface of the brush base 67. The rear end 94 extends above the trigger 44 and moves up and down relative to the upper surface of the trigger 44. A front locking portion 98 and a rear locking portion 99 are provided on the rear end 94, which protrude downward and are spaced apart from each other in the front and rear directions. The rear locking portion 99 protrudes downward further than the front locking portion 98. A front stopper piece 100 and a rear stopper piece 101 are formed on the upper surface of the trigger 44. The front stopper piece 100 is a plate-like piece that protrudes upward with a predetermined width in the left-right direction. The rear stopper piece 101 is a square block-like piece that extends rearward from the rear surface of the front stopper piece 100 and protrudes upward at a height lower than that of the front stopper piece 101.

[0030] When the trigger 44 is in a protruding position where it is not pressed (the OFF position of the switch 6) and the brush base 67 is in a neutral position, the lock lever 90 rotates rightward against the bias of the coil spring 95, as shown in Figs. 3 and 4, and assumes a first attitude (first position) in which the front end 93 rides on the upper surface of the projection 82. At this time, the rear end 94, which is in the lowest position, positions the front locking portion 98 behind the front stopper piece 100. Therefore, the trigger 44 is locked with the front locking portion 98, and the rearward pushing operation is restricted, and there is no risk of the motor 4 starting unexpectedly. From this, as shown in FIG. 7A, when the brush base 67 rotates to the normal rotation position, the lock lever 90 rotates left by the urging of the coil spring 95, and assumes a second posture (second position) in which the front end 93 is close to the outer circumferential surface of the brush base 67. A restricting protrusion 102 protruding upward is provided on the upper surface of the lock lever 90 above the boss 97. Two front and rear protrusions 103, 103 formed on the left half housing 3a and extending to the right are formed on the upper inner surface of the upper connection part 42. The restricting protrusion 102 abuts against the protrusions 103, 103, so that the lock lever 90 maintains the second posture in which the front end 93 does not contact the outer circumferential surface of the brush base 67. Thus, wear of the brush base 67 and the front end 93 is prevented. The restricting protrusion 102 and the protrusion 103 are an example of a restricting means of the present disclosure.

[0031] The rear end 94, which is the upper limit position in the second posture of the lock lever 90, is located above the trigger 44, with the front locking portion 98 located above the front stopper piece 100 and the rear locking portion 99 located above the rear stopper piece 101. This allows the trigger 44 to be pushed backward. At this time, front end 93, which is in the lowest position, is adjacent to protrusion 82 that has moved relatively in the circumferential direction, as shown in FIG. 7B, and their tapered surfaces are brought close to each other. When the trigger 44 is pressed, the rear stopper piece 101 approaches the lower part of the rear locking portion 99 of the rear end portion 94, as shown in Fig. 8. The vertical distance between the rear locking portion 99 and the rear stopper piece 101 is smaller than the vertical distance required for the front end portion 93, which approaches the outer circumferential surface of the brush base 67, to overcome the protrusion 82. Therefore, when the trigger 44 is pressed, i.e., when the switch 6 is in the ON state, the protrusion 82 interferes with the front end portion 93 at the lower limit position, thereby restricting the switching operation of the brush base 67 to the reverse position by the operating protrusion 80. This is the same when the brush base 67 is switched from the reverse position to the normal rotation position.

[0032] In the hammer drill 1 configured as described above, the trigger 44 is pressed with the brush base 67 in the forward or reverse rotation position, whereby the switch 6 is turned ON and the rotor 14 of the motor 4 rotates forward or reverse, enabling use in the selected operation mode. When using the hammer drill 1, the rear housing 3 is pressed forward by the hand of an operator holding the handle portion 41. This causes the rear housing 3 to move forward against the bias of the coil springs 51 of the vibration-proof mechanism 7. This causes the screw boss 56 to move away from the upper stopper 55. Therefore, even if vibrations occur in the output portion 5 or the motor accommodating portion 12 of the front housing 2, they are damped by the coil springs 51 and are less likely to be transmitted to the rear housing 3. This reduces the vibrations transmitted to the hand of the operator holding the handle portion 41, making it less likely that the operator will feel uncomfortable. Thus, even if the rear housing 3 moves forward relative to the front housing 2, the front end 93 of the lock lever 90 moves forward relative to the outer circumferential surface of the brush base 67, and the positional relationship in which it interferes with the protrusion 82 in the circumferential direction does not change. Therefore, the rotation direction of the rotor 14 cannot be changed even during the operation in which the vibration isolation mechanism 7 is operating.

[0033] When the trigger 44 is released from being pressed down and the switch 6 is turned OFF, the trigger 44 returns to the forward protruding position. Then, the rear stopper piece 101 is not close to the lower side of the rear locking portion 99 of the rear end portion 94, as shown in FIG. 7. Therefore, the brush base 67 can be rotated by the operating projection 80 to the neutral position, or to a reverse rotation position or a normal rotation position on the opposite side beyond the neutral position. At this time, since the projection 82 and the front end 93 of the brush base 67 are tapered in opposite directions, the front end 93 can ride up onto the projection 82 smoothly by being guided by the tapered surfaces.

[0034] Thus, the hammer drill 1 of the above embodiment includes a motor 4 including a stator 13, a rotor 14 having a commutator 15 and a rotating shaft 16, a brush base 67 which holds a pair of carbon brushes 76, 76 in contact with the commutator 15 and which can be switched between a forward rotation position, a reverse rotation position, and a neutral position between the forward rotation position and the reverse rotation position, centered on the commutator 15, a switch 6 which turns the motor 4 on and off, a trigger 44 which turns the switch 6 on when pressed, and a lock lever 90 whose front end 93 is positioned outside the brush base 67 in the radial direction of the rotor 14 and whose rear end 94 can be engaged and disengaged with the trigger 44. When the front end 93 of the lock lever 90 abuts against the outer peripheral surface of the brush base 67 in the radially neutral position, the rear end 94 of the lock lever 90 engages with the trigger 44, thereby taking the first position for restricting the pushing operation. According to this configuration, the front end 93 of the lock lever 90 abuts against the outer circumferential surface of the brush base 67 in the radial direction to restrict the pressing operation of the trigger 44, so that even if the front housing 2 and the rear housing 3 move relatively in the front-to-rear direction due to the vibration isolation mechanism 7 or even if there are dimensional errors or assembly errors in each component, the abutting state between the front end 93 and the outer circumferential surface of the brush base 67 can be maintained. Therefore, the trigger 44 can be locked at the neutral position of the brush base 67 with high reliability.

[0035] When the brush base 67 is in the forward rotation position or the reverse rotation position, the lock lever 90 is in a second position in which the rear end portion 94 is released from the engagement with the trigger 44 and the trigger 44 is allowed to be pressed. Therefore, if the brush base 67 is switched to the normal rotation position or the reverse rotation position, the trigger 44 can be pressed without any hindrance to turn the switch 6 ON. The lock lever 90 has a front end 93 and a rear end 94 each supported so that they can swing about the middle portion, and a protrusion 82 is provided on the outer surface of the brush base 67 which pushes the front end 93 radially outward when in the neutral position. As the front end 93 is pushed up, the rear end 94 swings to the opposite side and engages with the trigger 44, assuming the first position. Therefore, the rocking of the lock lever 90 can be utilized to easily regulate the depression operation of the trigger 44 . The lock lever 90 is capable of swinging about a pin 91 which is perpendicular to a plane that includes the axis of the rotation shaft 16 and is defined by the front-rear and up-down directions. Therefore, the lock lever 90 can be disposed in a well-balanced manner relative to the brush base 67.

[0036] When the trigger 44 is pressed in when the brush base 67 is in the forward or reverse rotation position, the trigger 44 restricts the swinging of the rear end 94 toward the trigger 44, thereby maintaining the lock lever 90 in the second position, while the front end 93 restricts the rotation of the brush base 67 by interfering with the protrusion 82 in the rotation direction of the brush base 67. Therefore, forward / reverse switching caused by rotation of the brush base 67 while the motor 4 is running can be reliably restricted, and shortening of the life of the brush base 67 due to forward / reverse switching while the motor 4 is running can be prevented. A restricting projection 102 and a protruding strip 103 are provided to restrict contact between the front end 93 and the outer circumferential surface of the brush base 67 when the lock lever 90 is in the second position. Therefore, wear caused by unnecessary sliding contact between the front end portion 93 and the brush base 67 can be prevented.

[0037] The projections 82 are tapered when viewed in the axial direction of the rotary shaft 16 such that their width in the rotational direction gradually decreases as they extend radially outward. Therefore, the front end 93 can smoothly ride up onto the projection 82 as the brush base 67 rotates. The front end portion 93 is tapered in such a way that the width in the rotational direction gradually decreases as it approaches the radially inner side when viewed in the axial direction of the rotary shaft 16 . Therefore, the front end 93 can ride up onto the projection 82 more smoothly as the brush base 67 rotates. A biasing means (coil spring 95) is provided for biasing the lock lever 90 to the second position. Therefore, when the brush base 67 is switched from the neutral position to the forward rotation position or the reverse rotation position, the lock lever 90 automatically assumes the second position, allowing the trigger 44 to be pressed. The biasing means is a coil spring 95 . Therefore, the biasing means can be easily formed.

[0038] The hammer drill 1 has a front housing 2 which houses the output section 5 having the tool holder 20 facing forward and the motor 4 and to which a brush base 67 is attached, and a rear housing 3 which houses a switch 6 and a lock lever 90 on the rear side of the front housing 2. The motor 4 is housed in the front housing 2 with the rotating shaft 16 facing in the fore-and-aft direction, the brush base 67 is located on the rear side of the motor 4, and the switch 6 is located on the rear axis of the rotating shaft 16 within a handle section 41 which is provided on the rear housing 3 and extends in the vertical direction, causing a trigger 44 to protrude forward. The lock lever 90 extends in the front-rear direction at the top of the rear housing 3 , with a front end 93 located above the brush base 67 and a rear end 94 located above the trigger 44 . Therefore, the lock lever 90 can be installed in a space-saving manner. The front housing 2 and the rear housing 3 are capable of moving relative to each other in the front-rear direction, and a vibration isolation mechanism 7 including a coil spring 51 is interposed between the front housing 2 and the rear housing 3. Therefore, the vibration transmitted to the hand of the operator holding the handle portion 41 can be reduced. An operating protrusion 80 for switching the rotational position of the brush base 67 passes through a window 81 formed in the upper surface of the rear housing 3 and protrudes upward. Therefore, the rotational position of the brush base 67 can be easily changed.

[0039] Modifications of the present disclosure will be described below. The biasing means for biasing the locking member to the second position is not limited to a coil spring. Fig. 9 shows an example in which a torsion spring is used as the biasing means. Here, both ends of a pin 105 penetrating the middle part of the locking lever 90 in the left-right direction are supported by receiving parts 92 to enable the locking lever 90 to swing. A torsion spring 106 is fitted to the pin 105 on the lower surface of the locking lever 90, and one end of the torsion spring 106 is abutted against the lower surface of the locking lever 90 and the other end is abutted against the lower inner surface of the upper connecting part 42, biasing the locking lever 90 to rotate left. In this way, even if the torsion spring 106 is provided as the biasing means, the biasing means can be easily formed. 10 shows an example in which a leaf spring is used as the biasing means. The leaf spring 107 here has a shape in which both left and right ends are curled downward in an inverted U-shape and an upward protruding portion 108 is formed in the center. This leaf spring 107 is arranged in the left-right direction between a pair of front and rear positioning portions 109, 109 provided in the left-right direction on the lower inner surface of the upper connection portion 42, and in a state in which it is compressed in the up-down direction, the protruding portion 108 is brought into contact with a receiving recess 110 provided on the lower surface of the lock lever 90. Therefore, the lock lever 90 is biased to rotate left by the leaf spring 107. In this way, even if the leaf spring 107 is provided as the biasing means, the biasing means can be easily formed. In the above embodiment and modified examples, the coil spring or leaf spring is disposed below the locking member and behind the fulcrum of the locking member, but the coil spring or leaf spring may be disposed above the locking member and in front of the fulcrum.

[0040] In the above embodiment, the front end of the lock lever is abutted from the radial outside against a protrusion provided on the outer peripheral surface of the brush base to hold the lock lever in the first position, but it is possible to hold the lock lever in the first position even without providing a protrusion on the outer peripheral surface of the brush base. 11 shows one example, in which a protrusion 83 is provided on the rear surface of the brush base 67, protruding rearward toward the trigger 44. The protrusion 83 may be formed integrally with the brush base 67, or may be formed by attaching a separate member to the brush base 67. Like the protrusion 82 in the above embodiment, the protrusion 83 is tapered such that its width in the rotational direction gradually decreases as it extends radially outward, and a front end 93 is tapered in the opposite direction to the protrusion 83. Here, when the trigger 44 is in the protruding position and the brush base 67 is in the neutral position, the front end 93 of the lock lever 90 abuts against the upper surface of the protrusion 83, thereby taking the first position and restricting the pressing operation of the trigger 44. When the brush base 67 rotates from this position to the forward rotation position or the reverse rotation position, the lock lever 90 rotates left by the bias of the coil spring 95, and in the second position in which the restricting protrusion 102 abuts against the ridges 103, 103, the front end 93 is located on the circumferential movement path of the protrusion 83, as shown by the two-dot chain line. Therefore, when the trigger 44 is pressed in and the second position of the lock lever 90 is maintained, the protrusion 83 interferes with the front end 93 at the lowest position, thereby restricting the switching operation of the brush base 67. In this modified example, the structure shown in Figs. 9 and 10 can be used as the lock lever biasing means.

[0041] The shape of the locking member itself is not limited to the lock lever of the above embodiment. The locking member may be rod-shaped instead of plate-shaped, and may be curved instead of straight. The shape of the front end portion may also be changed as appropriate as long as it is possible for the brush base to ride up onto the protrusion and interfere with the brush base in the rotational direction. Either the protrusion or the front end portion may not be tapered. The shape of the locking portion of the rear end portion may also be changed as long as it is possible for the trigger to be engaged and disengaged. The operating member is not limited to the trigger of the above embodiment, and may be a member having one end supported by a housing so as to be pivotable about the fulcrum, and the other end being pushed toward the switch side for operation. The configuration of the forward / reverse switching unit may also be modified as appropriate. For example, the operating protrusion may be protruded from the side surface of the housing to enable switching operation. The lead wire holder may be omitted. The handle portion may be formed downward from the rear end of the housing instead of being loop-shaped. In this case, the distance between the brush holding member and the operating member is shortened, and the locking member can be made shorter.

[0042] In the case of a hammer drill, the selectable operation modes are not limited to three. The position of the switching knob can also be changed as appropriate. The impact action may be a structure in which a piston reciprocates inside a fixed cylinder instead of a piston cylinder. A structure in which a striker directly strikes the bit without an impact bolt may be used. The impact action may be a structure in which a crank mechanism is used instead of a boss sleeve. The power tool is not limited to the hammer drill of the above embodiment, and the present disclosure can be applied to other power tools such as an electric hammer and an electric drill. The vibration-proof mechanism is not limited to the above embodiment. The number and positions of the coil springs can be changed as appropriate. Elastic members other than coil springs can also be used. However, the present disclosure can also be used in power tools that do not include a vibration-proof mechanism. [Explanation of symbols]

[0043] 1 hammer drill, 2 front housing, 3 rear housing, 4 motor, 5 output section, 6 switch, 7 vibration isolation mechanism, 8 motor housing, 9 outer housing, 10 inner housing, 11 connection section, 12 motor accommodating section, 13 stator, 14 rotor, 15 commutator, 16 rotating shaft, 20 tool holder, 40 outer cylinder section, 41 handle section, 42 upper connection section, 44 trigger, 50 rubber sleeve, 51 coil spring, 60 Bearing retaining portion, 65··forward / reverse switching unit, 66··unit base, 67··brush base, 68··fixed contact, 75··brush holder, 76··carbon brush, 78··movable contact, 80··operation protrusion, 82··protrusion, 83··protrusion portion, 90··lock lever, 91··pin, 93··front end portion, 94··rear end portion, 95··coil spring, 98··front locking portion, 99··rear locking portion, 100··front stopper piece, 101··rear stopper piece, 106··torsion spring, 107··leaf spring, B··bit.

Claims

1. a motor including a stator and a rotor having a commutator and a rotating shaft; a brush holding member that holds a pair of carbon brushes in contact with the commutator, and is switchable between a forward rotation position, a reverse rotation position, and a neutral position between the forward rotation position and the reverse rotation position, centered on the commutator; A switch for turning the motor on and off; An operating member that turns on the switch when pressed; a locking member having one end disposed on the outer side of the brush holding member or a protrusion protruding from the brush holding member toward the operating member in a radial direction of the rotor, and having the other end capable of being engaged with and disengaged from the operating member, The power tool is characterized in that, when one end of the locking member abuts against the outer surface or the protrusion of the brush holding member in the neutral position in the radial direction, the other end engages with the operating member to assume a first position that restricts the pushing operation.

2. The power tool according to claim 1, characterized in that, when the brush holding member is in the forward rotation position and the reverse rotation position, the locking member is in a second position in which the locking member releases the engagement of the other end with the operating member to allow the operating member to be pushed in.

3. The locking member is supported such that the one end and the other end can swing about an intermediate portion, a protrusion is provided on an outer circumferential surface of the brush holding member to push up the one end of the locking member radially outward when the brush holding member is in the neutral position; The power tool according to claim 2, wherein the other end portion swings to the opposite side in response to the one end portion being pushed up, and engages with the operating member to assume the first position.

4. The power tool according to claim 3 , wherein the fulcrum is set in a direction perpendicular to a plane including an axis of the rotation shaft.

5. When the operating member is pressed in when the brush holding member is in the forward rotation position or the reverse rotation position, the operating member restricts the swinging of the other end portion toward the operating member side to maintain the locking member in the second position, The electric power tool according to claim 3 or 4, wherein the one end portion restricts rotation of the brush holding member by interfering with the protrusion in a rotation direction of the brush holding member.

6. 5. The electric power tool according to claim 3, further comprising a restricting means for restricting contact between the one end of the locking member and an outer circumferential surface of the brush holding member when the locking member is in the second position.

7. The power tool according to claim 5 or 6, wherein the protrusion has a tapered shape such that a width in the rotational direction gradually decreases toward the outside in the radial direction when viewed from the axial direction of the rotating shaft.

8. The power tool according to claim 7, wherein the one end portion has a tapered shape such that a width in the rotational direction gradually decreases toward the radially inner side when viewed from the axial direction of the rotating shaft.

9. 9. The electric power tool according to claim 3, further comprising a biasing means for biasing the locking member to the first position.

10. The power tool according to claim 9, wherein the biasing means is a coil spring.

11. The power tool according to claim 9, wherein the biasing means is a torsion spring provided at the fulcrum.

12. The power tool according to claim 9, wherein the biasing means is a leaf spring.

13. a first housing that houses an output section having a final output shaft facing forward and the motor and to which the brush holding member is attached, and a second housing that houses the switch and the lock member on the rear side of the first housing, the motor is accommodated in the first housing with the rotation shaft oriented in a front-rear direction, and the brush holding member is disposed on the rear side of the motor, the switch is disposed on a rear axis of the rotation shaft within a handle portion that is provided in the second housing and extends in a vertical direction, and causes the operating member to protrude forward; An electric power tool as described in any one of claims 1 to 12, characterized in that the locking member extends in the front-to-rear direction at the top of the second housing, with the front end being located above the brush holding member and the rear end being located above the operating member.

14. The power tool according to claim 13, characterized in that the first housing and the second housing are movable relative to each other in the forward / rearward direction, and a vibration-damping mechanism including an elastic member is interposed between the first housing and the second housing.

15. The power tool according to claim 13 or 14, characterized in that an operating protrusion for switching the rotational position of the brush holding member protrudes upward through a window formed in an upper surface of the second housing.

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