Driver Drill

Abstract

The present invention handles variation while contributing to a reduction in size. In a driver drill 1, a switching ring 74 of a switching mechanism 70 for switching a striking-force-imparting mechanism 60 of the driver drill 1 to a non-operating state or an operating state is removably attached to a nut 51 of a clutch mechanism 50. Specifically, an attachment part 51C for attaching the switching ring 74 is provided to the nut 51, the switching ring 74 switching the operation mode of a spindle 33. This makes it possible to handle variation in the driver drill 1 while contributing to a reduction in physical size of the driver drill.

Description

Technical Field

[0001] The present invention relates to Driver Drill the following.

Background Art

[0002] In the driver drill (working machine) described in Patent Document 1 below, the driving force of the motor is transmitted to the spindle by a transmission mechanism composed of a planetary gear mechanism, and the spindle rotates. Thereby, for example, tightening processing or the like can be performed. Further, the driver drill has a clutch mechanism, and when the transmission torque transmitted to the spindle reaches the upper limit value, the driving force transmission to the spindle is blocked by the clutch mechanism. Furthermore, in the clutch mechanism, by rotating the clutch ring, the nut moves in the front-rear direction, and the upper limit value of the transmission torque can be changed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, there is also a driver drill having two modes: a rotation mode for applying a rotational force to the spindle and a rotation-impact mode for applying a rotational force and an impact force to the spindle. In a driver drill with a rotation-impact mode, an impact force applying mechanism for applying an impact force to the spindle and a switching mechanism for switching the mode from the rotation mode to the rotation-impact mode are added, and the switching mechanism is interlocked with the movement of the nut.

[0005] In driver drills with rotary impact mode, the switching mechanism is activated by a nut. This nut is larger than the nut in driver drills without rotary impact mode in order to operate the switching mechanism. Therefore, if the nut from the driver drill with rotary impact mode is used in the two types of driver drills mentioned above for the purpose of parts sharing, the driver drill without rotary impact mode becomes larger. In other words, it is desirable for the driver to have a structure that can accommodate various variations while also contributing to miniaturization.

[0006] Taking the above facts into consideration, the present invention aims to provide a work machine that can accommodate variations while contributing to miniaturization. [Means for solving the problem]

[0007] One or more embodiments of the present invention include a motor, a transmission mechanism that transmits the driving force of the motor to a spindle to rotate the spindle, and a clutch mechanism that cuts off the power transmission from the motor to the spindle when the torque transmitted to the spindle by the transmission mechanism reaches an upper limit. The system comprises a clutch spring that biases a member that engages with the transmission mechanism, a clutch dial that is rotated by an operator, and a mechanism that moves in the axial direction of the spindle as the clutch dial is rotated to change the amount of compression deformation of the clutch spring. Set the aforementioned upper limit It is a nut. Torque setting section, A clutch mechanism having; an impact force applying mechanism for applying impact force in the axial direction of the spindle, comprising a first ratchet that rotates integrally with the spindle, and a second ratchet whose ratchet teeth can engage with the first ratchet in the axial direction; a switching mechanism for switching the impact force applying mechanism between an operating state and a non-operating state, comprising a locking member movable between an unlocked position that allows rotation of the second ratchet and a locked position that prevents rotation of the second ratchet, and a switching ring as a switching member that is movable in the axial direction of the spindle in order to move the locking member; Equipped with, A driver drill having, as operating modes for the spindle, a rotation mode in which the impact force application mechanism is in a non-operating state, and a rotational impact mode in which the impact force application mechanism is activated by the switching mechanism moving the locking member to the locked position and preventing the rotation of the second ratchet, wherein the nut and the switching ring are formed in a cylindrical shape and located radially outward of the spindle, The aforementioned nut This switches the operating mode of the spindle. The aforementioned switching ring is made detachable. Having a mounting part for installation The driver drill is configured such that, with the switching ring attached to the mounting portion, the switching ring has a mounting portion which is attached to the mounting portion in a state where it is engaged with the nut in the circumferential direction and is locked to the mounting portion by a locking member, and with the switching ring attached to the mounting portion, the nut and the switching ring move together in the axial direction of the spindle as the clutch dial is rotated. That is the case.

[0008] One or more embodiments of the present invention are: The axial direction of the spindle extends in the front-rear direction, the power transmission mechanism including the transmission mechanism and the clutch mechanism has a gear case that constitutes the outer shell of the power transmission mechanism, the gear case is formed in a substantially stepped cylindrical shape with the front-rear direction as its axial direction, and has a front part and a rear part, the diameter of the front part is set to be smaller than the diameter of the rear part, a threaded portion made of male threads is formed on the outer circumference of the front part of the gear case, the nut has a female thread that is screwed into the threaded portion of the gear case, the clutch dial is rotatably connected to the gear case via the nut, the nut is configured to rotate relative to the gear case together with the clutch dial when the clutch dial is rotated by an operator, the mounting portion is provided at the front end of the nut, the switching ring is provided at the front end of the nut by being attached to the mounting portion, and the nut and the switching ring are arranged radially outward of the front part of the gear case, as described in claim 1. That is the case.

[0009] One or more embodiments of the present invention are as described above. nut It is arranged on one side in the axial direction relative to the transmission mechanism. ret The mounting portion is the nut It is provided at one end in the axial direction of the said, Switching ring However, as mentioned above nut It is positioned radially inward of the spindle. Driver Drill It is as follows.

[0011] In one or more embodiments of the present invention, the locking member is a C-ring attached to the mounting portion and the attached portion. Driver Drill It is as follows.

Advantages of the Invention

[0012] According to one or more embodiments of the present invention, it is possible to respond to variations while contributing to miniaturization.

Brief Description of the Drawings

[0013] [Figure 1] It is a longitudinal sectional view showing a driver drill according to this embodiment. [Figure 2] It is a longitudinal sectional view showing an enlarged view of the driving force transmission mechanism, the impact force applying mechanism, and the switching mechanism shown in FIG. 1. [Figure 3] It is an exploded perspective view of the clutch mechanism and the switching ring shown in FIG. 2 as viewed from the left rear obliquely. [Figure 4] It is an exploded perspective view of the clutch mechanism and the switching ring shown in FIG. 3 as viewed from the left front obliquely. [Figure 5] It is an exploded perspective view of the impact force applying mechanism and the switching mechanism shown in FIG. 2 as viewed from the left rear obliquely. [Figure 6] It is an exploded perspective view of the impact force applying mechanism and the switching mechanism shown in FIG. 5 as viewed from the left front obliquely. [Figure 7] It is a longitudinal sectional view corresponding to FIG. 2 showing variations of the driver drill.

Modes for Carrying Out the Invention

[0014] Hereinafter, the driver drill 1 as a working machine according to the present embodiment will be described with reference to the drawings. In the drawings, the arrows UP, FR, and RH shown as appropriate indicate the upper side, the front side, and the right side of the driver drill 1, respectively. In the following description, when the up-down, front-back, and left-right directions are used for explanation, unless otherwise specified, they indicate the up-down direction, the front-back direction, and the left-right direction of the driver drill 1.

[0015] As shown in FIG. 1, the driver drill 1 is configured as a power tool that attaches a tip tool to a chuck 35 provided at the front end of the driver drill 1, applies a rotational force to the tip tool, and performs fastening work or the like. Further, the driver drill 1 has two modes: a rotation mode for applying a rotational force to the tip tool and a rotary impact mode for applying a rotational force and an impact force to the tip tool, and is configured to be switchable between the rotation mode and the rotary impact mode.

[0016] The driver drill 1 includes a housing 10 that constitutes the outer shell of the driver drill 1, a motor 20 housed in the housing 10, a driving force transmission mechanism 30 that transmits the driving force of the motor 20 to a spindle 33, an impact force applying mechanism 60 for applying an impact force to the tip tool, and a switching mechanism 70 for switching the impact force applying mechanism 60 between a non-operating state and an operating state. Hereinafter, each component of the driver drill 1 will be described.

[0017] (Regarding the housing 10) When viewed from the right side, the housing 10 is formed in a hollow substantially I-shaped. Specifically, the housing 10 includes an upper housing portion 10A that constitutes the upper end portion of the housing 10 and extends in the front-back direction, a handle portion 10B that extends downward from the middle portion in the front-back direction of the upper housing portion 10A, and a lower housing portion 10C that constitutes the lower end portion of the housing 10. Note that the housing 10 is composed of a plurality of housing members, and the housing 10 is formed by assembling these housing members to each other.

[0018] A trigger 12 is provided at the upper end of the handle portion 10B. The trigger 12 protrudes forward from the handle portion 10B and is configured to be pullable backward. A switch mechanism 14 is provided on the handle portion 10B behind the trigger 12. The switch mechanism 14 has a switch (not shown), and when the trigger 12 is pulled, the switch is turned from off to on.

[0019] A controller 16 is provided in the lower housing section 10C. The switch of the switch mechanism 14 is electrically connected to the controller 16, and an output signal corresponding to the operating state of the trigger 12 is output from the switch to the controller 16. A battery 18 is also detachably mounted in the lower housing section 10C. The battery 18 is electrically connected to the controller 16, and power is supplied to the motor 20 by the battery 18.

[0020] (Regarding the motor 20) The motor 20 is housed in the rear end of the upper housing portion 10A and is electrically connected to the controller 16. The motor 20 consists of a drive shaft 21 whose axial direction is in the front-rear direction, a rotor 22 which is integrally rotatable with respect to the drive shaft 21, and a substantially cylindrical stator 23 which is located radially outward of the rotor 22.

[0021] The rear end of the drive shaft 21 is rotatably supported by a rear motor bearing 24 fixed to the housing 10. On the other hand, the front end portion of the drive shaft 21 is rotatably supported by a front motor bearing 25 fixed to a motor spacer 32. The motor spacer 32 is formed in a substantially disc shape with the front-to-rear direction as the thickness direction and is attached to the rear end of the gear case 31, which will be described later. The front end of the drive shaft 21 protrudes forward of the motor spacer 32 and is located inside the gear case 31. A pinion gear 21A is provided at the front end of the drive shaft 21.

[0022] (Regarding the drive force transmission mechanism 30) As shown in Figures 1 and 2, the drive force transmission mechanism 30 is composed of a gear case 31 that constitutes the outer casing of the drive force transmission mechanism 30, a reduction mechanism 40 that acts as a transmission mechanism for transmitting the driving force of the motor 20 to the spindle 33, and a clutch mechanism 50 that cuts off the drive transmission to the spindle 33 when the torque transmitted to the spindle 33 reaches an upper limit.

[0023] (Regarding the gear case 31) As shown in Figures 5 and 6, the gear case 31 is formed in a substantially stepped cylindrical shape with the front-to-back direction as the axial direction, and the diameter of the front part of the gear case 31 is set to be smaller than the diameter of the rear part of the gear case 31. The gear case 31 is housed in the front part of the upper housing part 10A. The motor spacer 32 described above is fitted into the rear end of the gear case 31, and the rear end of the gear case 31 is closed by the motor spacer 32. A spindle 33 with the front-to-back direction as the axial direction is provided in the front part of the gear case 31, and the spindle 33 is arranged coaxially with the drive shaft 21 of the motor 20. The front end portion of the spindle 33 is rotatably supported by a bearing 34 provided at the front end of the gear case 31. A chuck 35 is connected to the front end of the spindle 33, and the driving force from the motor 20 is transmitted to the tip tool mounted on the chuck 35.

[0024] A threaded portion 31A, composed of male threads, is formed on the outer circumference of the front part of the gear case 31, and the nut 51 of the clutch mechanism 50, which will be described later, is screwed onto the threaded portion 31A. A clutch dial 36 is also provided on the radially outer side of the front part of the gear case 31. The clutch dial 36 is formed in a substantially cylindrical shape that is open to the rear and is rotatably connected to the gear case 31 via the nut 51, which will be described later. A through hole 36A is formed through the front wall of the clutch dial 36, and the front end of the spindle 33 protrudes forward from the through hole 36A.

[0025] (Regarding the reduction mechanism 40) As shown in Figure 2, the reduction mechanism 40 is housed in the rear of the gear case 31. The reduction mechanism 40 is composed of a three-stage planetary gear mechanism. The first-stage planetary gear mechanism in the reduction mechanism 40 has a ring-shaped first ring gear 41, which is positioned radially outward of the pinion gear 21A of the motor 20 and is connected to the gear case 31 so as not to rotate relative to it. Internal teeth are formed on the inner circumference of the first ring gear 41. A plurality of first planetary gears 42 are provided between these internal teeth and the pinion gear 21A, and the first planetary gears 42 mesh with the pinion gear 21A and the first ring gear 41. A disc-shaped first carrier 43 is provided in front of the pinion gear 21A, and the first planetary gears 42 are rotatably supported by the first carrier 43. In other words, the pinion gear 21A is configured as a sun gear. A sun gear 43A protruding forward is formed in the center of the first carrier 43.

[0026] The second planetary gear mechanism in the reduction gear 40 has a ring-shaped second ring gear 44, which is positioned radially outward of the sun gear 43A and is connected to the gear case 31 so as not to rotate relative to it. Internal teeth are formed on the inner circumference of the second ring gear 44. A plurality of second planetary gears 45 are provided between these internal teeth and the sun gear 43A, and the second planetary gears 45 mesh with the sun gear 43A and the second ring gear 44. A disc-shaped second carrier 46 is provided in front of the sun gear 43A, and the second planetary gears 45 are rotatably supported by the second carrier 46. A sun gear 46A protruding forward is formed in the central part of the second carrier 46.

[0027] The third planetary gear mechanism in the reduction gear 40 has a ring-shaped third ring gear 47, which is positioned radially outward of the sun gear 46A and rotatably supported by the gear case 31. Multiple engaging protrusions 47A are formed on the front surface of the third ring gear 47. The engaging protrusions 47A engage with a clutch mechanism 50, which will be described later, and the clutch mechanism 50 holds the third ring gear 47 in a non-rotatable position. Internal teeth are formed on the inner circumference of the third ring gear 47. A third planetary gear 48 is provided between these internal teeth and the sun gear 46A, and the third planetary gear 48 meshes with the sun gear 46A and the third ring gear 47. A disc-shaped third carrier 49 is provided in front of the sun gear 46A, and the third planetary gear 48 is rotatably supported by the third carrier 49. A mating hole 49A is formed through the center of the third carrier 49. The rear end of the spindle 33 is connected to the mating hole 49A so as to be unable to rotate relative to it but movable relative to it in the front-rear direction. As a result, the rotational force of the motor 20 is transmitted by the reduction mechanism 40, causing the spindle 33 to rotate.

[0028] (Regarding the clutch mechanism 50) As shown in Figures 2 to 4, the clutch mechanism 50 is composed of a nut 51 as a torque setting part, a thrust plate 52, a clutch spring 53, and a plurality of balls 54. The nut 51 is formed in a substantially cylindrical shape with the front-rear direction as the axial direction. A threaded portion 51A is provided on the inner circumference of the nut 51, and a female thread is formed on the threaded portion 51A. The nut 51 is fitted onto the front of the gear case 31, and the threaded portion 51A is screwed into the threaded portion 31A of the gear case 31. In addition, a flange portion 51B that protrudes radially outward is formed on the front end of the nut 51, and the flange portion 51B is positioned close to the radially inward side of the clutch dial 36 and is connected to the clutch dial 36 so as to be able to rotate integrally with the clutch dial 36 and so as to be able to rotate relative to it in the front-rear direction. As a result, when the clutch dial 36 is rotated by an operator, the nut 51 rotates relative to the gear case 31 together with the clutch dial 36. Furthermore, at this time, the screw connection between the nut 51 and the gear case 31 causes the nut 51 to move relative to the gear case 31 and the clutch dial 36 in the front-rear direction. Specifically, the nut 51 is configured to move between a separated position (the position shown above the spindle 33 in Figure 2) and a closer position (the position shown below the spindle 33 in Figure 2) which is a rearward movement from the separated position.

[0029] A mounting portion 51C is formed at the front end of the nut 51 for attaching the switching ring 74 of the switching mechanism 70, which will be described later. The mounting portion 51C is composed of a plurality of mounting protrusions 51D (four in this embodiment) and a plurality of mounting recesses 51F (four in this embodiment). The mounting protrusions 51D are formed in a rib shape that protrudes forward from the inner circumference of the front end of the nut 51 and extends along the circumferential direction of the nut, and the front end of the mounting protrusions 51D is bent radially outward of the nut 51. That is, a locking groove portion 51E is formed in the mounting protrusions 51D that is open radially outward of the nut 51 and extends in the circumferential direction of the nut 51. The four mounting protrusions 51D are spaced equally apart (90 degrees apart) in the circumferential direction of the nut 51.

[0030] The mounting recess 51F is formed on the inner circumference of the front end of the nut 51 and is positioned between adjacent mounting protrusions 51D in the circumferential direction. That is, the mounting protrusions 51D and the mounting recess 51F are arranged alternately in the circumferential direction of the nut 51. The mounting recess 51F extends in the circumferential direction of the nut 51 and is formed as a concave shape that opens to the front. The radially inner inner surface of the mounting recess 51F is positioned one step lower radially inward of the nut 51 than the bottom surface of the locking groove 51E.

[0031] The thrust plate 52 is formed in a substantially annular shape with the front-to-back direction being the thickness direction. The thrust plate 52 is externally fitted to the front part of the gear case 31 and is located at the rear end of the front part. The clutch spring 53 is configured as a compression coil spring. The clutch spring 53 is externally fitted to the nut 51, the front end of the clutch spring 53 is locked to the flange portion 51B, and the rear end of the clutch spring 53 is locked to the thrust plate 52. As a result, the clutch spring 53 biases the thrust plate 52 toward the rear.

[0032] Multiple balls (six in this embodiment) 54 are inserted into the rear of the gear case 31 through ball holes 31B (see Figure 6) formed in the gear case 31 and positioned between the thrust plate 52 and the third ring gear 47. As a result, the biasing force of the clutch spring 53 is transmitted to the balls 54 via the thrust plate 52, and the balls 54 press the third ring gear 47 toward the rear. When the reduction mechanism 40 is operated, the engaging projection 47A of the third ring gear 47 engages with the balls 54, holding the third ring gear 47 in a non-rotatable position, and the driving force of the motor 20 is transmitted to the spindle 33. On the other hand, when the torque transmitted to the spindle 33 reaches its upper limit during tightening work, etc., the balls 54, pressed by the engaging projection 47A of the third ring gear 47, are displaced toward the front together with the thrust plate 52 against the biasing force of the clutch spring 53, and the balls 54 overcome the engaging projection 47A. This causes the third ring gear 47 to rotate, interrupting the transmission of power to the spindle 33.

[0033] Furthermore, by rotating the clutch dial 36 to move the nut 51 from the separated position to the rear (closed position), the amount of compression deformation of the clutch spring 53 increases, and the biasing force of the clutch spring 53 increases. Therefore, by rotating the clutch dial 36, the upper limit of the torque transmitted to the spindle 33 during tightening work can be changed. Note that in the close position of the nut 51, the rear end of the nut 51 abuts the thrust plate 52 from the front. For this reason, the movement of the thrust plate 52 toward the front is restricted, and the clutch mechanism 50 is set to be in a non-operating state.

[0034] (Regarding the impact force application mechanism 60) As shown in Figures 2, 5, and 6, the impact force application mechanism 60 comprises a first ratchet 61, a second ratchet 62, and a biasing spring 63 (broadly speaking, an element that is grasped as a biasing member). The impact force application mechanism 60 is arranged radially outward from the axial middle portion of the spindle 33 and is housed in the front part of the gear case 31. The first ratchet 61 is formed in a substantially cylindrical shape with the front-rear direction as its axial direction, and the axial middle portion of the spindle 33 is fitted into the first ratchet 61 so that the first ratchet 61 is fixed to the spindle 33 so as to be integrally rotatable. Multiple ratchet teeth are formed on the rear surface of the first ratchet 61, and the multiple ratchet teeth are arranged in the circumferential direction of the first ratchet 61. The first ratchet 61 is located adjacent to the rear side of the bearing 34.

[0035] The second ratchet 62, like the first ratchet 61, is formed in a substantially cylindrical shape with its axial direction in the front-rear direction. The second ratchet 62 is supported on the rear side of the first ratchet 61 so as to be rotatable relative to the spindle 33. Multiple ratchet teeth are formed on the front surface of the second ratchet 62, and these multiple ratchet teeth are configured to engage with the ratchet teeth of the first ratchet 61. When fastening or other operations are performed, pressing the tip tool against the workpiece causes the spindle 33 to move to the rear, causing the ratchet teeth of the first ratchet 61 and the second ratchet 62 to engage with each other. In addition, multiple ratchet pawls 62A are formed on the outer circumference of the second ratchet 62, and the ratchet pawls 62A are arranged at equal intervals in the circumferential direction of the second ratchet 62.

[0036] The biasing spring 63 is configured as a compression coil spring and is externally fitted onto the spindle 33. The biasing spring 63 is housed in recesses formed on the inner circumference of the first ratchet 61 and the second ratchet 62, biasing both outward in the front-rear direction. As will be described in detail later, when the impact force application mechanism 60 is not in operation, the second ratchet 62, which engages with the first ratchet 61, rotates integrally with the first ratchet 61, so that no impact force is applied to the spindle 33. On the other hand, when the impact force application mechanism 60 is in operation, the rotation of the second ratchet 62 is prevented by the switching mechanism 70, which will be described later. As a result, the ratchet teeth of the first ratchet 61 overcome the ratchet teeth of the second ratchet 62 against the biasing force of the biasing spring 63, thereby applying an impact force to the spindle 33 in the front-rear direction.

[0037] (Regarding the switching mechanism 70) As shown in Figures 2 to 6, the switching mechanism 70 is composed of a pair of slip blocks 71 (broadly speaking, elements that are grasped as locking members), a pair of stopper springs 73, and a switching ring 74 as a switching member. The pair of slip blocks 71 are arranged radially outward of the impact force application mechanism 60 and are housed slidably in the front direction within the front part of the gear case 31, and are arranged 180 degrees apart in the circumferential direction of the gear case 31. Specifically, the slip blocks 71 are configured to slide between an unlocked position (the position shown above the spindle 33 in Figure 2) and a locked position (the position shown below the spindle 33 in Figure 2). In the unlocked position, the front part of the slip block 71 is positioned radially outward of the first ratchet 61, and in the locked position, the front part of the slip block 71 is positioned radially outward of the second ratchet 62.

[0038] Multiple locking pawls 71A are formed on the front of the slip block 71, corresponding to the ratchet pawls 62A of the second ratchet 62. The locking pawls 71A are arranged at equal intervals in the circumferential direction of the slip block 71. In the locked position of the slip block 71, the locking pawls 71A are inserted between adjacent ratchet pawls 62A in the circumferential direction of the second ratchet 62, and the locking pawls 71A and the ratchet pawls 62A engage in the circumferential direction, preventing the rotation of the second ratchet 62. In other words, the impact force application mechanism 60 switches from a non-operating state to an operating state.

[0039] The slip block 71 is provided with a pin 72 whose axial direction is aligned with the radial direction of the spindle 33. The pin 72 protrudes radially outward from the slip block 71 toward the spindle 33 and is slidably inserted in the front-rear direction into a slit 31C formed in the gear case 31. The tip of the pin 72 protrudes radially outward from the gear case 31 and is positioned in front of the threaded portion 51A of the nut 51.

[0040] The stopper spring 73 is configured as a compression coil spring. The stopper spring 73 is housed in the front part of the gear case 31 and positioned behind the slip block 71, biasing the slip block 71 forward. As a result, the slip block 71 is held in the unlocked position by the biasing force of the stopper spring 73.

[0041] The switching ring 74 is formed in a roughly cylindrical shape with a relatively short axial length, with the front-to-back direction as its axial direction. The switching ring 74 is detachably attached to the mounting portion 51C of the nut 51 and is positioned on the front side of the nut 51. The rear end of the switching ring 74 is provided with a mounting portion 74A that is attached to the mounting portion 51C. The mounting portion 74A has four mounting protrusions 74B that correspond to the mounting recess 51F of the nut 51. The mounting protrusions 74B are formed in a rib shape that extends in the circumferential direction of the switching ring 74, and the front end of the mounting protrusions 74B is bent radially outward of the switching ring 74. That is, the mounting protrusions 74B have locking grooves 74C that open radially outward of the switching ring 74 and extend in the circumferential direction of the switching ring 74. The mounting protrusions 74B are then fitted into the mounting recess 51F of the nut 51 from the front, and the switching ring 74 is mounted in a state where it is engaged with the nut 51 in the circumferential direction. When the switching ring 74 is attached to the nut 51, the locking groove 51E of the nut 51 and the locking groove 74C of the switching ring 74 are in circumferential communication. A C-ring 75 is fitted into the locking grooves 51E and 74C, and the switching ring 74 is locked to the nut 51 by the C-ring 75, maintaining the attached state of the switching ring 74.

[0042] The switching ring 74 is provided with a pair of pressing pieces 74D. The pressing pieces 74D are positioned radially inward from the mounting projection 74B and protrude rearward from the switching ring 74. The pressing pieces 74D are formed in a substantially rectangular plate shape with the radial direction of the switching ring 74 being the thickness direction and the circumferential direction of the switching ring 74 being the longitudinal direction. The pair of pressing pieces 74D are positioned 180 degrees apart in the circumferential direction of the switching ring 74 and are positioned corresponding to the pin 72 of the slip block 71. When the nut 51 is in the separated position, the pressing pieces 74D are positioned to be separated forward from the pin 72 of the slip block 71 in the unlocked position. On the other hand, when the nut 51 is in the close position, the pressing pieces 74D press the pin 72 of the slip block 71 rearward, causing the slip block 71 to be in the locked position.

[0043] (Effects and Effects) Next, the effects and functions of this embodiment will be described.

[0044] When performing fastening work using the driver drill 1 configured as described above, the driver bit, as the cutting tool, is attached to the chuck 35, and the driver drill 1 is set to rotation mode. In rotation mode, the nut 51 is positioned in front of the approach position. When the motor 20 is driven by the operator pulling the trigger 12, the driving force of the motor 20 is transmitted to the spindle 33 by the reduction mechanism 40, and the cutting tool rotates together with the spindle 33. Furthermore, when the torque transmitted to the spindle 33 reaches its upper limit, the clutch mechanism 50 is activated, and the drive transmission to the spindle 33 is interrupted. Specifically, the third ring gear 47 of the reduction mechanism 40 rotates relative to the ball 54 against the biasing force of the clutch spring 53. This interrupts the drive transmission to the spindle 33. In addition, by rotating the clutch dial 36 to move the nut 51 to the rear, the amount of compression deformation of the clutch spring 53 increases. This allows the operator to change the upper limit of the torque transmitted to the spindle 33.

[0045] In the rotation mode of the driver drill 1, the slip block 71 of the switching mechanism 70 has not reached the locked position, and the impact force application mechanism 60 remains inactive. That is, when the tip tool is pressed against the workpiece during the tightening operation, the spindle 33 moves to the rear, and the ratchet teeth of the first ratchet 61 of the impact force application mechanism 60 engage with the ratchet teeth of the second ratchet 62, but relative rotation of the second ratchet 62 is permitted. Therefore, the second ratchet 62 rotates together with the spindle 33 along with the first ratchet 61, and the impact force application mechanism 60 remains inactive.

[0046] On the other hand, for example, when a drill as a cutting tool is attached to the chuck 35 and drilling work is performed, the driver drill 1 is set to rotary impact mode. In the rotary impact mode of the driver drill 1, the operator rotates the clutch dial 36 to move the nut 51 to the approach position. As a result, the rear end of the nut 51 comes into contact with the thrust plate 52 from the front, restricting the forward movement of the thrust plate 52. This causes the clutch mechanism 50 to become inactive. Also, when the nut 51 is in the approach position, the pin 72 of the slip block 71 is pressed by the pressing piece 74D of the switching ring 74, and the slip block 71 is placed in the locked position. As a result, the locking pawl 71A of the slip block 71 and the ratchet pawl 62A of the second ratchet 62 of the impact force application mechanism 60 are positioned to engage in the circumferential direction of the second ratchet 62, that is, the rotation of the second ratchet 62 is prevented, and the impact force application mechanism 60 becomes active.

[0047] Then, when the tip tool is pressed against the workpiece during operation, the spindle 33 moves to the rear, and the ratchet teeth of the first ratchet 61 and the second ratchet 62 engage with each other. When the spindle 33 rotates due to the driving force of the motor 20, the rotation of the second ratchet 62 is prevented by the slip block 71, so the ratchet teeth of the first ratchet 61 overcome the biasing force of the biasing spring 63 and pass over the ratchet teeth of the second ratchet 62. As a result, a striking force is applied to the spindle 33 and the tip tool when the spindle 33 rotates.

[0048] In the driver drill 1, the switching ring 74 of the switching mechanism 70, which switches the impact force application mechanism 60 of the driver drill 1 between a non-operating state and an operating state, is detachably attached to the nut 51 of the clutch mechanism 50. In other words, the nut 51 is provided with a mounting portion 51C for attaching the switching ring 74 that switches the operating mode of the spindle 33. This contributes to miniaturization of the device while accommodating variations of the driver drill 1.

[0049] In other words, as shown in Figure 7, when manufacturing a driver drill 100 that only has a rotation mode, the driver drill 100 is configured by omitting the impact force application mechanism 60 and the switching mechanism 70 compared to the driver drill 1. That is, the driver drill 100 can be constructed by removing the switching ring 74 of the switching mechanism 70 from the nut 51 and deleting the impact force application mechanism 60 and the switching mechanism 70 compared to the driver drill 1. This makes it possible to reduce the size of the driver drill 100 in the front-to-back direction compared to configuring a nut with the nut 51 and switching ring 74 integrated as a common part for the driver drill 1 and the driver drill 100. Therefore, it is possible to accommodate variations of the driver drill 1 while contributing to a smaller size. Furthermore, in the driver drill 100, a smaller driver drill 100 can be manufactured compared to the driver drill 1 by manufacturing a gear case 31 etc. that corresponds to the dimensions of the nut 51 in the front-to-back direction.

[0050] Furthermore, the nut 51 is positioned in front of the reduction mechanism 40 and is configured to be movable in the front-rear direction. In addition, the mounting portion 51C of the nut 51 is provided at the front end of the nut 51, and the slip block 71 of the switching mechanism 70 is positioned radially inward of the nut 51. This makes it possible to further reduce the size of the driver drill 1 in the front-rear direction. That is, if the mounting portion 51C were provided at the rear end of the nut 51, the switching ring 74 would be positioned behind the threaded portion 51A of the nut 51. As a result, the slip block 71 and the impact force application mechanism 60, which are operated by the switching ring 74, would be positioned further back compared to this embodiment. Therefore, in this case, the gear case 31 and spindle 33 would need to be extended forward compared to this embodiment. That is, the size of the driver drill 1 would tend to be larger in the front-rear direction. In contrast to this, in this embodiment, the mounting portion 51C is provided at the front end of the nut 51. Therefore, the switching ring 74 can be positioned in front of the threaded portion 51A of the nut 51, and the slip block 71 and impact force application mechanism 60, which are operated by the switching ring 74, can be positioned radially inward of the threaded portion 51A of the nut 51. Consequently, the size of the driver drill 1 in the front-to-back direction can be further reduced.

[0051] Furthermore, the mounting projection 74B of the switching ring 74 is fitted into the mounting recess 51F of the nut 51, so that the mounting portion 74A and the mounting portion 51C are engaged in the circumferential direction of the nut 51. The C-ring 75 is attached to the locking groove 51E of the nut 51 and the locking groove 74C of the switching ring 74, and the C-ring 75 restricts the movement of the switching ring 74 in the front-rear direction relative to the nut 51. In other words, the mounting state of the switching ring 74 is maintained by the C-ring 75. This allows the switching ring 74 to be attached to the nut 51 with a simple configuration and improves the ease of attaching the switching ring 74 to the nut 51. [Explanation of Symbols]

[0052] 1…Driver drill (working tool), 20…Motor, 33…Spindle, 40…Reduction mechanism (transmission mechanism), 50…Clutch mechanism, 51…Nut (torque setting part), 51C…Mounting part, 60…Impact force application mechanism, 70…Switching mechanism, 74…Switching ring (switching member), 74A…Mounted part, 75…C-ring (locking member)

Claims

1. Motor and, A transmission mechanism that transmits the driving force of the motor to the spindle to rotate the spindle, A clutch mechanism for interrupting power transmission from the motor to the spindle when the torque transmitted to the spindle by the transmission mechanism reaches an upper limit, comprising: a clutch spring for biasing a member that engages with the transmission mechanism; a clutch dial that is rotated by an operator; and a torque setting part which is a nut that moves in the axial direction of the spindle in accordance with the rotation of the clutch dial, thereby changing the amount of compression deformation of the clutch spring and setting the upper limit; A striking force applying mechanism for applying striking force in the axial direction of the spindle, comprising: a first ratchet that rotates integrally with the spindle; and a second ratchet whose ratchet teeth can engage with the first ratchet in the axial direction; A switching mechanism for switching the impact force application mechanism between an operating state and a non-operating state, comprising: a locking member movable between an unlocked position that allows rotation of the second ratchet and a locked position that prevents rotation of the second ratchet; and a switching ring as a switching member movable in the axial direction of the spindle in order to move the locking member; Equipped with, A driver drill having, as operating modes for the spindle, a rotation mode in which the impact force application mechanism is in a non-operating state, and a rotational impact mode in which the impact force application mechanism is activated by the switching mechanism moving the locking member to the locked position and preventing the rotation of the second ratchet, The nut and the switching ring are formed in a cylindrical shape and are located radially outward of the spindle. The nut has a mounting portion for detachably attaching the switching ring, which switches the operating mode of the spindle. The switching ring has a mounting portion which is attached to the mounting portion, The mounting portion is attached to the mounting portion in a state in which it is engaged with the nut in the circumferential direction, and is locked to the mounting portion by a locking member. A driver drill configured such that, with the switching ring attached to the mounting portion, both the nut and the switching ring move in the axial direction of the spindle as the clutch dial is rotated.

2. The axial direction of the spindle extends in the front-rear direction, The power transmission mechanism, including the transmission mechanism and the clutch mechanism, has a gear case that constitutes the outer casing of the power transmission mechanism. The gear case is formed in a substantially stepped cylindrical shape with the front-rear direction as the axial direction, and has a front part and a rear part, with the diameter of the front part being smaller than the diameter of the rear part. A threaded portion, formed by a male screw, is formed on the outer circumference of the front part of the gear case. The nut has a female thread that is screwed into the threaded portion of the gear case, The clutch dial is rotatably connected to the gear case via the nut, The nut is configured to rotate relative to the gear case together with the clutch dial when the clutch dial is rotated by an operator. The mounting portion is provided at the front end of the nut, The switching ring is attached to the mounting portion and is provided at the front end of the nut. The driver drill according to claim 1, wherein the nut and the switching ring are arranged radially outward from the front part of the gear case.

3. The nut is positioned on one side in the axial direction with respect to the transmission mechanism, The driver drill according to claim 1, wherein the mounting portion is provided on one axial end of the nut, and the switching ring is positioned radially inward of the spindle relative to the nut.

4. The driver drill according to claim 1, wherein the locking member is a C-ring attached to the mounting portion and the portion to be mounted.

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