JP2024011331A - Screw driver - Google Patents

Abstract

To inhibit scattering of a lubricant.SOLUTION: A screw driver includes: a housing; a motor; a clutch cam which is disposed inside the housing and is rotated around a center axis by the motor; a spindle which is disposed at the front relative to the clutch cam, has a driven cam part which faces a driving cam part provided at the clutch cam, and a rod part to which a tip tool is attached, and is supported by the housing in a manner that enables its movement in an anteroposterior direction so that the driving cam part and the driven cam part contact with or separate from each other; and a sleeve which is disposed at a radial outer side relative to the driving cam part and the driven cam part at an inner side of the housing.SELECTED DRAWING: Figure 5

Description

The technology disclosed herein relates to a screwdriver.

In the technical field related to screwdrivers, a screw tightening machine as disclosed in Patent Document 1 is known.

Patent No. 5382430

The screwdriver has a clutch mechanism. A lubricant such as grease is applied to the clutch mechanism. If the lubricant is scattered around, there is a possibility that the lubricant will be depleted in the clutch mechanism. Loss of lubricant in the clutch mechanism can accelerate wear of the clutch mechanism and shorten the life of the screwdriver.

The technology disclosed herein aims to suppress scattering of lubricant.

A screwdriver is disclosed herein. The screwdriver may include a housing, a motor, a clutch cam disposed inside the housing, and a spindle disposed ahead of the clutch cam. The clutch cam may be rotated by a motor around a rotating shaft. The spindle may have a driven cam portion that faces a driving cam portion provided on the clutch cam, and a rod portion to which the tip tool is attached. The spindle may be supported by the housing so as to be movable in the front-back direction so that the driving cam part and the driven cam part come into contact with each other or are separated from each other. The screwdriver may include a sleeve disposed inside the housing and radially outward from the drive cam part and the driven cam part.

According to the technology disclosed in this specification, scattering of lubricant is suppressed.

FIG. 1 is a perspective view from the front showing a screwdriver according to an embodiment. FIG. 2 is a perspective view from the rear showing the screwdriver according to the embodiment. FIG. 3 is a side view showing the screwdriver according to the embodiment. FIG. 4 is a longitudinal sectional view showing the screwdriver according to the embodiment. FIG. 5 is a partially enlarged vertical cross-sectional view of the screwdriver according to the embodiment. FIG. 6 is a cross-sectional view showing the screwdriver according to the embodiment. FIG. 7 is a partially enlarged cross-sectional view of the screwdriver according to the embodiment. FIG. 8 is an exploded perspective view from the front showing the power transmission mechanism according to the embodiment. FIG. 9 is an exploded perspective view from the rear showing the power transmission mechanism according to the embodiment. FIG. 10 is an exploded perspective view from the front showing the clutch mechanism and cam sleeve according to the embodiment. FIG. 11 is an exploded perspective view from the rear showing the clutch mechanism and cam sleeve according to the embodiment. FIG. 12 is a diagram of the clutch cam according to the embodiment viewed from the rear. FIG. 13 is a longitudinal sectional view showing the clutch mechanism and cam sleeve according to the embodiment. FIG. 14 is an exploded perspective view from the front showing the spindle lock mechanism according to the embodiment. FIG. 15 is an exploded perspective view from the rear showing the spindle lock mechanism according to the embodiment. FIG. 16 is a perspective view from the front showing the intermediate shaft according to the embodiment. FIG. 17 is a side view showing the intermediate shaft according to the embodiment. FIG. 18 is a front view of the intermediate shaft according to the embodiment. FIG. 19 is a perspective view from the rear showing the spindle according to the embodiment. FIG. 20 is a side view showing the spindle according to the embodiment. FIG. 21 is a longitudinal sectional view showing the spindle according to the embodiment. FIG. 22 is a cross-sectional view of the spindle according to the embodiment. FIG. 23 is a sectional view showing a part of the screwdriver when the rotor is rotated normally and no pushing operation is being performed. FIG. 24 is an enlarged view of portion B in FIG. 23. FIG. 25 is a cross-sectional view taken along line HH in FIG. 24. FIG. 26 is an enlarged view of portion C in FIG. 25. FIG. 27 is a sectional view showing a part of the screwdriver when the rotor is rotated normally and a pushing operation is performed. FIG. 28 is an enlarged view of portion B in FIG. 27. FIG. 29 is a cross-sectional view taken along line HH in FIG. 28. FIG. 30 is an enlarged view of portion C in FIG. 29. FIG. 31 is a cross-sectional view of a portion of the screwdriver when the rotor is reversed and no pushing operation is being performed. FIG. 32 is an enlarged view of portion B in FIG. 31. FIG. 33 is a cross-sectional view taken along line HH in FIG. 31. FIG. 34 is an enlarged view of portion C in FIG. 33. FIG. 35 is a cross-sectional view of a portion of the screwdriver when the rotor is reversed and a pushing operation is being performed. FIG. 36 is an enlarged view of portion B in FIG. 35. FIG. 37 is a cross-sectional view taken along line HH in FIG. 36. FIG. 38 is an enlarged view of portion C in FIG. 37.

In one or more embodiments, the screwdriver may include a housing, a motor, a clutch cam disposed inside the housing, and a spindle disposed forward of the clutch cam. The clutch cam may be rotated by a motor around a rotating shaft. The spindle may have a driven cam portion that faces a driving cam portion provided on the clutch cam, and a rod portion to which the tip tool is attached. The spindle may be supported by the housing so as to be movable in the front-back direction so that the driving cam part and the driven cam part come into contact with each other or are separated from each other. The screwdriver may include a sleeve disposed inside the housing radially outward of the drive cam part and the driven cam part.

In the above configuration, the sleeve is disposed inside the housing radially outward from the drive cam part and the driven cam part of the clutch mechanism, so that the lubricant such as grease applied to the drive cam part and the driven cam part is Scattering around the sleeve is suppressed. As a result, a state in which the lubricant is applied to the drive cam portion and the driven cam portion is maintained, and a decrease in lubricant in the clutch mechanism is suppressed. Therefore, wear of the drive cam part and the driven cam part is suppressed, and shortening of the life of the screwdriver is suppressed. Furthermore, the sleeve suppresses noise generated when the drive cam part and the driven cam part come into contact with each other from being transmitted to the surroundings of the screwdriver.

In one or more embodiments, the clutch cam may have a cam ring portion disposed about the axis of rotation. The drive cam portion may be provided so as to protrude forward from the front surface of the cam ring portion. The spindle may have a flange portion provided at the rear end of the rod portion. The driven cam portion may be provided so as to protrude rearward from the rear surface of the flange portion. The sleeve may be supported by each of the cam ring portion and the flange portion.

In the above configuration, each of the driving cam part and the driven cam part is arranged inside the closed space defined by the cam ring part, the flange part, and the sleeve. Therefore, the lubricant applied to the drive cam part and the driven cam part is effectively prevented from scattering around the sleeve. Furthermore, the sleeve effectively suppresses noise generated when the drive cam part and the driven cam part come into contact with each other from being transmitted to the surroundings of the screwdriver.

In one or more embodiments, the screwdriver may include a front O-ring located on the outer periphery of the flange portion and contacting the sleeve.

In the above configuration, the boundary between the sleeve and the flange portion is sealed by the front O-ring. This effectively prevents the lubricant applied to the drive cam portion and the driven cam portion from scattering around the sleeve. Moreover, the transmission of noise to the surroundings of the screwdriver when the driving cam part and the driven cam part come into contact is effectively suppressed.

In one or more embodiments, the screwdriver may include a rear O-ring located on the outer periphery of the cam ring portion and contacting the sleeve.

In the above configuration, the boundary between the sleeve and the cam ring portion is sealed by the rear O-ring. This effectively prevents the lubricant applied to the drive cam portion and the driven cam portion from scattering around the sleeve. Moreover, the transmission of noise to the surroundings of the screwdriver when the driving cam part and the driven cam part come into contact is effectively suppressed.

In one or more embodiments, the drive cam portion and the follower cam portion may be spaced apart with the spindle in the advanced position. The drive cam portion and the driven cam portion may be able to come into contact with each other when the spindle is disposed at a retracted position rearward than the forward position. With the spindle in the forward position, the rotational force of the clutch cam may be transmitted to the spindle via the sleeve.

In the above configuration, the sleeve is supported by the cam ring part and the flange part, so when the clutch cam rotates, the rotational force of the clutch cam is reduced due to the friction between the sleeve and the cam ring part and the friction between the sleeve and the flange part. It is transmitted to the spindle via the sleeve. When a front O-ring is provided, friction between the sleeve and the front O-ring causes the rotational force of the clutch cam to be transmitted to the spindle via the sleeve and the front O-ring. The spindle rotates due to friction between the sleeve and the front O-ring. When the rear O-ring is provided, the rotational force of the clutch cam is transmitted to the spindle via the rear O-ring and the sleeve due to friction between the sleeve and the rear O-ring. The spindle rotates due to friction between the sleeve and the rear O-ring. When both the rear O-ring and the front O-ring are arranged, the rotational force of the clutch cam is transferred to the rear O-ring, the sleeve, and the friction between the sleeve and the front O-ring. It is transmitted to the spindle via the front O-ring. The spindle rotates due to friction between the sleeve and the rear O-ring and friction between the sleeve and the front O-ring. Since the rotational force of the clutch cam is transmitted to the spindle by friction, the spindle rotates at a rotational speed lower than the rotational speed of the clutch cam while the driving cam part and the driven cam part are separated from each other. This allows the spindle to move toward the retracted position while rotating at a rotational speed lower than the rotational speed of the clutch cam. Since the spindle rotates and moves toward the retracted position due to the rotational force of the clutch cam transmitted through the sleeve, the drive cam portion and the The relative rotational speed between the clutch cam and the spindle when the driven cam portion comes into contact with each other becomes low. Therefore, the impact when the drive cam part and the driven cam part come into contact is reduced. Therefore, generation of noise due to contact between the drive cam part and the driven cam part is suppressed.

In one or more embodiments, the screwdriver may include a brake member supported by the housing to prevent rotation of the spindle when the spindle is in an advanced position.

In the above configuration, even if the rotational force of the clutch cam is transmitted to the spindle through the sleeve while the spindle is in the forward position, the rotation of the spindle is prevented by the brake member. Since unnecessary rotation of the spindle is suppressed, the operator can smoothly perform the operation of inserting the tip tool into the cross groove of the screw, for example.

In one or more embodiments, the spindle may have a front cam portion that projects forwardly from a front surface of the flange portion. The brake member may include a brake ring portion supported by the housing and a brake cam portion that contacts the front cam portion when the spindle is in the forward position.

In the above configuration, rotation of the spindle is prevented by contact between the front cam portion of the flange portion and the brake cam portion of the brake member.

In one or more embodiments, when the spindle moves from the forward position to an intermediate position between the forward position and the retracted position, rotation is no longer blocked by the brake member and the spindle begins to rotate. good.

In the above configuration, rotation of the spindle is started at an intermediate position before the spindle moves to the retracted position. Since the spindle is rotating when it moves from the intermediate position to the retreat position, the relative rotational speed between the clutch cam and the spindle when the drive cam part and the driven cam part come into contact becomes low. Therefore, the impact when the drive cam part and the driven cam part come into contact is reduced. Therefore, generation of noise due to contact between the drive cam part and the driven cam part is suppressed.

In one or more embodiments, the screwdriver may include a drive gear that is at least partially located behind the clutch cam and that is rotated by a motor about a rotation axis. The clutch cam may be supported by the drive gear. The sleeve may include a cylindrical portion disposed around each of the cam ring portion and the flange portion, and a stopper portion that contacts the front surface of the drive gear.

In the above configuration, when the spindle moves from the forward position to the retracted position, the sleeve may move rearward together with the spindle due to, for example, friction between the sleeve and the front O-ring. Since the sleeve has a stopper portion that contacts the front surface of the drive gear, even if the spindle moves rearward, the sleeve is prevented from moving rearward together with the spindle.

In one or more embodiments, the clutch cam may include a cam ball groove on the rear surface of the cam ring portion. The cam ball groove may be arcuate in a plane perpendicular to the rotation axis. At least a portion of the cam ball groove may be inclined in the front-rear direction. The screwdriver may include a ball located in a cam ball groove. The clutch cam may be coupled to the drive gear via a ball. The clutch cam may move forward when the drive cam part and the driven cam part come into contact.

In the above configuration, the clutch cam can rotate together with the drive gear when the spindle is in the forward position and the drive cam part and the driven cam part are separated from each other. When the spindle moves from the forward position to the backward position and the drive cam part and the driven cam part come into contact, the clutch cam receives a resistance force in the rotational direction from the spindle, and as a result, the balls roll in the cam ball groove and the drive gear and the clutch cam rotate relative to each other via the ball. Since at least a portion of the cam ball groove is inclined in the front-rear direction, the clutch cam can be moved forward by relative rotation between the drive gear and the clutch cam via the ball.

In one or more embodiments, the screwdriver may include a compression spring located radially inward of the sleeve and biasing the clutch cam rearward. When the torque applied to the rotating spindle decreases due to the rotational force of the clutch cam transmitted via the drive cam section and the driven cam section, the compression spring moves the clutch cam rearward, causing the drive cam section and the driven cam section to move backward. may be separated.

In the above configuration, at the beginning of the screw tightening operation using the screwdriver, the spindle is pushed backward through the tip tool, and the spindle moves from the forward position to the backward position. When the spindle moves from the forward position to the backward position, the drive cam part and the driven cam part come into contact, and the clutch cam moves forward. At the end of the screw tightening operation using the screwdriver, the torque applied to the spindle via the tip tool decreases, so the contact force between the drive cam section and the driven cam section decreases. When the contact force between the drive cam section and the driven cam section decreases, the clutch cam moves rearward due to the compression spring. As a result, the driving cam part and the driven cam part are separated from each other, and the rotation of the spindle is stopped.

Hereinafter, embodiments will be described with reference to the drawings. The components of the embodiments described below can be combined as appropriate. Furthermore, some components may not be used.

In the embodiment, the positional relationship of each part will be described using terms such as left, right, front, rear, upper, and lower. These terms indicate relative positions or directions with respect to the center of the screwdriver 1. In the embodiment, the screwdriver 1 has a spindle 9 that rotates around a rotation axis CX.

In the embodiment, a direction parallel to the rotation axis CX is appropriately referred to as an axial direction, a direction going around the rotation axis CX is appropriately referred to as a circumferential direction or a rotation direction, and a radial direction of the rotation axis CX is appropriately referred to as an axial direction. , radial direction.

A direction or position spaced apart from the center of the screwdriver 1 in a prescribed direction in the axial direction is appropriately referred to as one axial side, and a side opposite to the one axial side is appropriately referred to as the other axial side. A prescribed direction in the circumferential direction is appropriately referred to as one side in the circumferential direction, and a side opposite to the one side in the circumferential direction is appropriately referred to as the other side in the circumferential direction. The direction or position away from the rotation axis AX in the radial direction is appropriately referred to as the radially outer side, and the side opposite to the radially outer side is appropriately referred to as the radially inner side.

In embodiments, the axial direction and the front-back direction coincide. One side in the axial direction may be regarded as the front. The other side in the axial direction may be regarded as the rear side.

[Screwdriver]
FIG. 1 is a perspective view from the front showing a screwdriver 1 according to an embodiment. FIG. 2 is a perspective view from the rear showing the screwdriver 1 according to the embodiment. FIG. 3 is a side view showing the screwdriver 1 according to the embodiment. FIG. 4 is a longitudinal sectional view showing the screwdriver 1 according to the embodiment. FIG. 5 is a partially enlarged vertical cross-sectional view of the screwdriver 1 according to the embodiment. FIG. 6 is a cross-sectional view showing the screwdriver 1 according to the embodiment. FIG. 7 is a partially enlarged cross-sectional view of the screwdriver 1 according to the embodiment.

The screwdriver 1 includes a main body housing 2, a gear housing 3, a hook 4, a battery mounting part 5, a motor 6, a fan 7, a power transmission mechanism 8, a spindle 9, a brake member 82, and a tool holder. Mechanism 10, lock ring 11, adjustment sleeve 12, rubber cap 13, trigger lever 14, lock button 15, forward/reverse switching lever 16, light 17, switch plate 18, push drive mechanism 19. , and a controller 20.

The main body housing 2 accommodates at least some of the components of the screwdriver 1. The main body housing 2 is composed of a pair of half housings. The main body housing 2 includes a left housing 2L and a right housing 2R located to the right of the left housing 2L. The left housing 2L and the right housing 2R are fixed with a plurality of screws 2S.

The main body housing 2 includes a motor accommodating portion 21 , a handle portion 22 , a battery holding portion 23 , and a connecting portion 24 .

The motor accommodating portion 21 accommodates at least a portion of the motor 6 and the power transmission mechanism 8. The motor housing portion 21 is cylindrical. The motor accommodating portion 21 extends in the front-rear direction.

The handle portion 22 is held by the operator. The handle portion 22 includes a grip portion 22A extending in the vertical direction and a connecting portion 22B extending forward from the top of the grip portion 22A. The front end of the connecting part 22B is connected to the upper part of the rear end of the motor housing part 21.

The battery holding section 23 holds the battery pack 25 via the battery mounting section 5. The battery holding section 23 houses the controller 20. A lower end portion of the grip portion 22A is connected to a rear portion of the battery holding portion 23.

The connecting part 24 is arranged to connect the lower part of the motor accommodating part 21 and the front part of the battery holding part 23.

A loop portion of the main body housing 2 is formed by the rear portion of the motor accommodating portion 21, the connecting portion 24, the battery holding portion 23, and the handle portion 22.

An intake port 26 and an exhaust port 27 are provided in the motor housing portion 21 . The intake port 26 is provided at each of the left and right parts of the motor accommodating portion 21 . The exhaust port 27 is provided at the lower part of the motor accommodating portion 21 . Air in the external space of the main body housing 2 flows into the internal space of the main body housing 2 through the intake port 26. Air in the internal space of the main body housing 2 flows out to the external space of the main body housing 2 through the exhaust port 27.

Gear housing 3 accommodates at least a portion of power transmission mechanism 8 . Gear housing 3 accommodates at least a portion of spindle 9. At least a portion of the gear housing 3 is arranged forward of the main body housing 2.

Gear housing 3 includes a rear housing 31 and a front housing 32. At least a portion of the front housing 32 is disposed further forward than the rear housing 31. At least a portion of the rear housing 31 is disposed inside the front portion of the motor accommodating portion 21 . The front housing 32 is disposed further forward than the motor accommodating portion 21 .

The rear housing 31 includes a plate portion 31A, a recess portion 31B recessed rearward from the upper portion of the plate portion 31A, and a cylindrical portion 31C protruding rearward from the lower portion of the plate portion 31A. The front housing 32 includes a plate portion 32A and a cylindrical portion 32B that projects forward from the plate portion 32A.

The gear housing 3 is fixed to the front part of the motor accommodating part 21. The front part of the motor accommodating part 21, the plate part 31A of the rear housing 31, and the plate part 32A of the front housing 32 are fixed with three screws 3S. A seal ring 3C is arranged between the plate portion 31A and the plate portion 32A.

The hook 4 is hung on a predetermined object. The hook 4 is hung, for example, on at least part of the worker's clothing or on the worker's belt. The hook 4 is fixed to the left side of the battery holding part 23 by a screw 4S. Further, a hand strap 28 is attached to the rear part of the battery holding section 23. Hand strap 28 is held by the operator.

A battery pack 25 is attached to the battery attachment part 5. The battery mounting part 5 is arranged at the lower part of the battery holding part 23. The battery pack 25 can be attached to and detached from the battery mounting section 5. The battery pack 25 functions as a power source for the screwdriver 1. The battery pack 25 is mounted on the battery mounting section 5 by being inserted into the battery mounting section 5 from the front of the battery holding section 23 . The battery pack 25 is removed from the battery mounting section 5 by being pulled forward from the battery mounting section 5. Battery pack 25 includes a secondary battery. In embodiments, battery pack 25 includes a rechargeable lithium ion battery. By being attached to the battery attachment part 5, the battery pack 25 can supply power to the screwdriver 1. The motor 6 is driven based on electric power supplied from the battery pack 25. Each of the controller 20 and the switch plate 18 operates based on electric power supplied from the battery pack 25.

The motor 6 is a power source for the screwdriver 1. The motor 6 is an electric motor that is driven based on electric power supplied from the battery pack 25. The motor 6 is an inner rotor type brushless motor. The motor 6 has a stator 33 and a rotor 34. The stator 33 is supported by the motor housing section 21 . At least a portion of rotor 34 is arranged inside stator 33. The rotor 34 rotates relative to the stator 33. The rotor 34 rotates around a rotation axis AX that extends in the front-rear direction.

The stator 33 includes a stator core 35, a rear insulator 36R, a front insulator 36F, and a coil 37.

Stator core 35 is arranged radially outward of rotor 34 with respect to rotation axis AX. Stator core 35 includes a plurality of laminated steel plates. A steel plate is a metal plate whose main component is iron. Stator core 35 is cylindrical. Stator core 35 has a plurality of teeth that support coil 37.

The rear insulator 36R is fixed to the rear of the stator core 35. Front insulator 36F is fixed to the front of stator core 35. Each of the rear insulator 36R and the front insulator 36F is an electrically insulating member made of synthetic resin. The rear insulator 36R is arranged to cover a part of the surface of the teeth of the stator core 35. The front insulator 36F is arranged so as to cover a part of the surface of the teeth of the stator core 35.

Coil 37 is attached to stator core 35 via rear insulator 36R and front insulator 36F. A plurality of coils 37 are arranged. Coil 37 is arranged around the teeth of stator core 35 via rear insulator 36R and front insulator 36F. Stator core 35 and coil 37 are electrically insulated by rear insulator 36R and front insulator 36F. The plurality of coils 37 are connected to each other via a shorting member 38. Current from the battery pack 25 is supplied to the coil 37 via the controller 20, a lead wire (not shown), and a connector 39 fixed to the lower part of the rear insulator 36R. The connector 39 is fixed to the lower part of the rear insulator 36R with a screw 39S.

The rotor 34 rotates around the rotation axis AX. The rotor 34 has a rotor core 40, a rotor shaft 41, and a rotor magnet 42.

Each of the rotor core 40 and the rotor shaft 41 is made of steel. Rotor shaft 41 is fixed to rotor core 40. Rotor core 40 has a cylindrical shape. The rotor shaft 41 is arranged radially inside the rotor core 40. The front portion of the rotor shaft 41 projects forward from the front end surface of the rotor core 40. The rear part of the rotor shaft 41 projects rearward from the rear end surface of the rotor core 40.

Rotor magnet 42 is fixed to rotor core 40. Rotor magnet 42 is arranged inside rotor core 40 . The rotor magnet 42 is arranged in a magnet hole provided in the rotor core 40.

Sleeve 29 is arranged to face the front end surface of rotor core 40 . Sleeve 29 is fixed to rotor core 40 and rotor shaft 41, respectively. The sleeve 29 is provided to adjust the rotational balance of the rotor 34.

A rotation sensor board 43 is attached to the rear insulator 36R. The rotation sensor board 43 is fixed to the rear insulator 36R with screws 43S. The rotation sensor board 43 includes an annular circuit board and a magnetic sensor supported by the circuit board. At least a portion of the rotation sensor board 43 faces the rotor magnet 42. The magnetic sensor detects the position of the rotor 34 in the rotational direction by detecting the position of the rotor magnet 42 . A detection signal from the magnetic sensor is transmitted to the controller 20 via a lead wire (not shown).

A rear end portion of the rotor shaft 41 is rotatably supported by a rotor bearing 44. A front portion of the rotor shaft 41 is rotatably supported by a rotor bearing 45. Each of rotor bearing 44 and rotor bearing 45 is a ball bearing. The rotor bearing 44 is held in a recess 21A provided at the rear of the inner surface of the motor accommodating portion 21. The front end of the inner ring of the rotor bearing 44 contacts a step provided at the rear of the rotor shaft 41. This suppresses relative movement of the rotor bearing 44 in the front-rear direction with respect to the rotor shaft 41. The rotor bearing 45 is held in the cylindrical portion 31C of the rear housing 31. The rear end of the inner ring of the rotor bearing 45 contacts a step provided at the front of the rotor shaft 41 . A circlip 46 is arranged in front of the rotor bearing 45. The circlip 46 contacts the front end of the inner ring of the rotor bearing 45. Thereby, relative movement of the rotor bearing 45 in the front-back direction with respect to the rotor shaft 41 is suppressed. The front end of the rotor shaft 41 is disposed inside the front housing 32 through an opening provided at the front end of the cylindrical portion 31C.

A pinion gear 47 is fixed to the front end of the rotor shaft 41. Pinion gear 47 is connected to at least a portion of power transmission mechanism 8 . The rotor shaft 41 is connected to the power transmission mechanism 8 via a pinion gear 47.

Fan 7 generates airflow for cooling motor 6. Fan 7 is arranged ahead of stator 33. Fan 7 is arranged between rotor bearing 45 and stator 33. Fan 7 is fixed to rotor shaft 41 between rotor bearing 45 and stator 33. The main body housing 2 has a fan case portion 2A arranged around the fan 7. The fan 7 rotates as the rotor 34 rotates. As the rotor shaft 41 rotates, the fan 7 rotates together with the rotor shaft 41. As the fan 7 rotates, air in the external space of the main body housing 2 flows into the internal space of the main body housing 2 through the intake port 26 . The air that has flowed into the internal space of the main body housing 2 cools the motor 6 by circulating through the internal space of the main body housing 2 . The air flowing through the internal space of the main body housing 2 flows out into the external space of the main body housing 2 through the exhaust port 27 due to the rotation of the fan 7 .

The power transmission mechanism 8 transmits the rotational force of the motor 6 to the spindle 9. The power transmission mechanism 8 rotates the spindle 9 at a rotation speed lower than the rotation speed of the rotor shaft 41. In the embodiment, the power transmission mechanism 8 includes a clutch mechanism 8A that transmits the rotational force of the motor 6 to the spindle 9 when the motor 6 rotates in the normal direction, and a clutch mechanism 8A that transmits the rotational force of the motor 6 to the spindle 9 when the motor 6 rotates in the reverse direction. It has a spindle lock mechanism 8B.

FIG. 8 is an exploded perspective view from the front showing the power transmission mechanism 8 according to the embodiment. FIG. 9 is an exploded perspective view from the rear showing the power transmission mechanism 8 according to the embodiment. FIG. 10 is an exploded perspective view from the front showing the clutch mechanism 8A and sleeve 76 according to the embodiment. FIG. 11 is an exploded perspective view from the rear showing the clutch mechanism 8A and sleeve 76 according to the embodiment. FIG. 12 is a diagram of the clutch cam 72 according to the embodiment viewed from the rear. FIG. 13 is a longitudinal sectional view showing the clutch mechanism 8A and sleeve 76 according to the embodiment. FIG. 14 is an exploded perspective view from the front showing the spindle lock mechanism 8B according to the embodiment. FIG. 15 is an exploded perspective view from the rear showing the spindle lock mechanism 8B according to the embodiment. FIG. 16 is a perspective view from the front showing the intermediate shaft 74 according to the embodiment. FIG. 17 is a side view showing the intermediate shaft 74 according to the embodiment. FIG. 18 is a front view of the intermediate shaft 74 according to the embodiment.

The power transmission mechanism 8 includes a drive gear 71, a clutch cam 72, a ball 73, an intermediate shaft 74, a compression spring 75, a sleeve 76, a rear O-ring 77, a front O-ring 78, and a lock pin 79. , a sleeve 80 , and a compression spring 81 .

The clutch mechanism 8A includes a clutch cam 72 coupled to the drive gear 71 via a ball 73, and a compression spring 75 that urges the spindle 9 forward. The drive gear 71, the clutch cam 72, and the compression spring 75 are arranged inside the gear housing 3.

The spindle lock mechanism 8B includes an intermediate shaft 74 coupled to a drive gear 71, a plurality of lock pins 79 arranged around the intermediate shaft 74, and a sleeve 80 arranged so as to contact the front end of the lock pin 79. and a compression spring 81 that biases the lock pin 79 rearward via the sleeve 80. The intermediate shaft 74, the lock pin 79, the sleeve 80, and the compression spring 81 are arranged inside the gear housing 3.

Drive gear 71 meshes with pinion gear 47. Drive gear 71 is a helical gear. Drive gear 71 is arranged above pinion gear 47. The rotation of the rotor shaft 41 of the motor 6 causes the pinion gear 47 to rotate around the rotation axis AX. The rotation of the pinion gear 47 causes the drive gear 71 to rotate around the rotation axis CX. The drive gear 71 includes a ring portion 71A, a gear portion 71B provided on the outer periphery of the ring portion 71A and meshing with the pinion gear 47, and a cylindrical portion 71C that protrudes forward from the front surface of the ring portion 71A and to which the clutch cam 72 is coupled. . The drive gear 71 is housed in the rear housing 31.

Clutch cam 72 is coupled to drive gear 71 via a plurality of balls 73. At least a portion of the drive gear 71 is arranged rearward than the clutch cam 72. Clutch cam 72 is supported by drive gear 71 via a plurality of balls 73. Drive gear 71 supports clutch cam 72 from behind clutch cam 72 . The rotation of the drive gear 71 causes the clutch cam 72 to rotate about the rotation axis CX. The clutch cam 72 includes a cam ring portion 72A disposed around the rotation axis CX, a ring groove 72B provided on the outer periphery of the cam ring portion 72A, and a drive portion provided so as to protrude forward from the front surface of the cam ring portion 72A. It has a cam portion 72C and a cam ball groove 72D provided on the rear surface of the cam ring portion 72A and in which the ball 73 is disposed.

In the embodiment, three balls 73 are provided. Three cam ball grooves 72D are provided at the rear of the cam ring portion 72A. Each of the three cam ball grooves 72D has an arc shape in a plane perpendicular to the rotation axis CX. As shown in FIG. 13, at least a portion of the cam ball groove 72D is inclined in the front-rear direction. The cam ball groove 72D is provided so as to surround the rotation axis CX. One ball 73 is arranged in one cam ball groove 72D.

The cylindrical portion 71C of the drive gear 71 is provided with a gear ball groove 71D in which the ball 73 is disposed. Three gear ball grooves 71D are provided on the outer peripheral surface of the cylindrical portion 71C. Each of the three gear ball grooves 71D has an arc shape in a plane perpendicular to the rotation axis CX. Gear ball groove 71D is provided so as to surround rotation axis CX. One ball 73 is arranged in one gear ball groove 71D.

Intermediate shaft 74 is fixed to drive gear 71. The rear part of the intermediate shaft 74 is inserted into an opening provided in the center of the drive gear 71. A rear end portion of the intermediate shaft 74 is rotatably supported by the shaft bearing 62. Shaft bearing 62 is a ball bearing. The shaft bearing 62 is held in the recess 31B of the rear housing 31. Clutch cam 72 is arranged around intermediate shaft 74 . A front end portion of the intermediate shaft 74 is arranged inside the accommodation hole 9D of the spindle 9.

The intermediate shaft 74 has a through hole 74A in which the rod 55 is placed. The intermediate shaft 74 also includes a bearing holding part 74B held by the shaft bearing 62, a gear fixing part 74C to which the drive gear 71 is fixed, an intermediate part 74D disposed inside the compression spring 75, and a lock pin 79. It has a pin support part 74E that supports the sleeve 80, and a sleeve support part 74F that supports the sleeve 80. The gear fixing part 74C is arranged further forward than the bearing holding part 74B. The intermediate portion 74D is disposed further forward than the gear fixing portion 74C. The pin support portion 74E is arranged further forward than the intermediate portion 74D. The sleeve support portion 74F is arranged further forward than the pin support portion 74E. The outer diameter of the pin support portion 74E is smaller than the outer diameter of the intermediate portion 74D.

A step is provided at the boundary between the intermediate portion 74D and the pin support portion 74E. A stop surface 74G is provided at the boundary between the intermediate portion 74D and the pin support portion 74E. The stop surface 74G is arranged at the rear end of the pin support section 74E. The stop surface 74G faces forward. The lock pin 79 is arranged so as to contact the outer circumferential surface of the pin support portion 74E. The rear end surface of the lock pin 79 faces the stop surface 74G.

A convex portion 74H is provided on the pin support portion 74E. The convex portion 74H is provided so as to protrude radially outward from the outer peripheral surface of the pin support portion 74E. The convex portion 74H is long in the front-rear direction. A plurality of convex portions 74H are provided at intervals in the circumferential direction. In the embodiment, three convex portions 74H are provided at equal intervals in the circumferential direction. The lock pin 79 is arranged between a pair of adjacent protrusions 74H. Three lock pins 79 are provided.

As shown in FIG. 18, a protruding portion 74M is provided on the outer peripheral surface of the pin support portion 74E between a pair of adjacent convex portions 74H. The raised portion 74M is provided at the rear portion of the outer peripheral surface of the pin support portion 74E. Moreover, a small diameter part 74J and a large diameter part 74K are provided in the pin support part 74E between a pair of mutually adjacent convex parts 74H. Between a pair of mutually adjacent convex portions 74H, the radial distance LK between the rotation axis CX and the outer circumferential surface of the large diameter portion 74K is greater than the radial distance between the rotation axis CX and the outer circumference of the small diameter portion 74J. It's also big. The distance LK indicates the outer diameter of the pin support portion 74E at the large diameter portion 74K. The distance LJ indicates the outer diameter of the pin support portion 74E at the small diameter portion 74J. The outer diameter of the pin support portion 74E gradually increases from the small diameter portion 74J toward the large diameter portion 74K. The lock pin 79 disposed in the large diameter portion 74K is disposed radially outward from the lock pin 79 disposed in the large diameter portion 74K. The lock pin 79 moves outward in the radial direction by moving from the small diameter portion 74J to the large diameter portion 74K in the circumferential direction.

Compression spring 75 is arranged around intermediate shaft 74 . Compression spring 75 is arranged radially inward than sleeve 76 . The rear end of the compression spring 75 contacts the front surface of the clutch cam 72. The front end of the compression spring 75 contacts the rear surface of the spindle 9. In the embodiment, an annular groove 9K is provided on the rear surface of the spindle 9. The front end of the compression spring 75 is arranged inside the groove 9K. Compression spring 75 urges clutch cam 72 rearward. Compression spring 75 urges spindle 9 forward.

Sleeve 76 is arranged to surround intermediate shaft 74 . The sleeve 76 is arranged to surround each of the cam ring portion 72A of the clutch cam 72 and the flange portion 9B of the spindle 9. The sleeve 76 is supported by the cam ring portion 72A of the clutch cam 72 and the flange portion 9B of the spindle 9, respectively. The sleeve 76 includes a cylindrical portion 76A and a stopper portion 76B that protrudes radially outward from the rear end of the outer peripheral surface of the cylindrical portion 76A. The cylindrical portion 76A is arranged around each of the cam ring portion 72A of the clutch cam 72 and the flange portion 9B of the spindle 9. The stopper portion 76B contacts the front surface of the gear portion 71B of the drive gear 71. The rear surface of the stopper portion 76B contacts the front surface of the gear portion 71B, thereby suppressing the sleeve 76 from moving rearward with respect to the drive gear 71. As shown in FIGS. 5 and 7, an O-ring 64 is disposed around the front end of the sleeve 76.

The rear O-ring 77 is attached to the clutch cam 72. The rear O-ring 77 is arranged on the outer circumference of the cam ring portion 72A. The rear O-ring 77 is arranged inside a ring groove 72B provided on the outer circumference of the cam ring portion 72A.

The front O-ring 78 is attached to the spindle 9. The front O-ring 78 is arranged on the outer periphery of the flange portion 9B. The front O-ring 78 is arranged inside the ring groove 9H provided on the outer circumference of the flange portion 9B.

Each of the rear O-ring 77 and the front O-ring 78 contacts the sleeve 76. The rear O-ring 77 contacts the rear portion of the inner circumferential surface of the sleeve 76 . The front O-ring 78 contacts the front portion of the inner peripheral surface of the sleeve 76 .

Lock pin 79 is supported by intermediate shaft 74 . Four lock pins 79 are arranged around the intermediate shaft 74.

The sleeve 80 is arranged in front of the lock pin 79 inside the accommodation hole 9D. The rear surface of the sleeve 80 contacts the front end surface of the lock pin 79. The sleeve 80 functions as a centering member when the spindle 9 moves back and forth with respect to the intermediate shaft 74. Sleeve 80 functions as a sliding bearing that supports intermediate shaft 74. A recess 80A for supplying grease is formed on the inner peripheral surface of the sleeve 80.

The compression spring 81 is arranged between the front surface of the sleeve 80 and the support surface 9E of the spindle 9 inside the accommodation hole 9D. A front end of the compression spring 81 is connected to a support surface 9E disposed in front of the accommodation hole 9D of the spindle 9. The rear end of the compression spring 81 is connected to the front surface of the sleeve 80. The compression spring 81 urges the lock pin 79 rearward so that the rear end surface of the lock pin 79 is pressed against the stop surface 74G.

The spindle 9 is rotated by the rotational force of the motor 6. At least a portion of the spindle 9 is arranged ahead of the power transmission mechanism 8. The spindle 9 is arranged ahead of the clutch cam 72. The spindle 9 rotates around a rotation axis CX. The rotation axis AX of the motor 6 and the rotation axis CX of the spindle 9 are different. The rotation axis AX and the rotation axis CX are parallel. The spindle 9 is rotated by a rotor 34. The spindle 9 is rotated by the rotational force of the rotor 34 transmitted by the power transmission mechanism 8. The spindle 9 rotates while holding a driver bit 30, which is a tip tool.

FIG. 19 is a perspective view from the rear showing the spindle 9 according to the embodiment. FIG. 20 is a side view showing the spindle 9 according to the embodiment. FIG. 21 is a longitudinal sectional view showing the spindle 9 according to the embodiment. FIG. 22 is a sectional view of the spindle 9 according to the embodiment, and corresponds to the sectional view taken along line AA in FIG.

The spindle 9 has a rod portion 9A, a flange portion 9B, a bit holding hole 9C, and an accommodation hole 9D. The rod portion 9A is arranged to extend in the front-rear direction. The flange portion 9B is provided at the rear of the rod portion 9A. The flange portion 9B is provided at the rear end portion of the rod portion 9A. The flange portion 9B protrudes radially outward from the rear end portion of the rod portion 9A. The bit holding hole 9C is provided so as to extend rearward from the front end surface of the rod portion 9A. The driver bit 30 is attached to the rod portion 9A. The driver bit 30 is inserted into the bit holding hole 9C from the front of the bit holding hole 9C. The cross section of the bit holding hole 9C perpendicular to the rotation axis CX is a regular hexagon. The accommodation hole 9D is provided so as to extend forward from the rear end surface of the spindle 9. A support surface 9E is provided at the front end of the accommodation hole 9D. The support surface 9E faces rearward. A cylindrical portion 9P is provided at the rear of the spindle 9 by the accommodation hole 9D. An oil seal 63 is arranged around the rod portion 9A. The oil seal 63 is held in the cylindrical portion 32B of the front housing 32.

The spindle 9 is rotatably supported by a spindle bearing 48. Spindle bearing 48 is a slide bearing. Spindle bearing 48 is held in front housing 32. The outer peripheral surface of the spindle bearing 48 is provided with a groove 48A in which the circlip 61 is arranged. At least a portion of the circlip 61 is held by the front housing 32. The circlip 61 suppresses relative movement between the spindle bearing 48 and the front housing 32 in the front-back direction. The spindle 9 is rotatably supported by a spindle bearing 48 and is supported so as to be movable in the front-rear direction with respect to the front housing 32. The spindle 9 is supported by the gear housing 3 via a spindle bearing 48 so as to be movable in the front-rear direction. The spindle 9 is movable in the front-rear direction between a forward position and a retracted position rearward of the forward position.

The spindle 9 has a driven cam portion 9G that faces a driving cam portion 72C provided on the clutch cam 72. The driven cam portion 9G is provided on the rear surface of the spindle 9. The driven cam portion 9G is provided so as to protrude rearward from the rear surface of the flange portion 9B. The drive cam portion 72C of the clutch cam 72 and the driven cam portion 9G of the spindle 9 face each other. The spindle 9 is supported by the gear housing 3 through the spindle bearing 48 so as to be movable in the front-rear direction so that the drive cam part 72C and the driven cam part 9G come into contact with each other or are separated from each other. With the spindle 9 in the forward position, the drive cam portion 72C and the driven cam portion 9G are separated. With the spindle 9 in the retracted position, the drive cam portion 72C and the driven cam portion 9G are in a state where they can come into contact with each other. The sleeve 76 is arranged inside the gear housing 3 radially outside of the drive cam section 72C and the driven cam section 9G.

The brake member 82 prevents rotation of the spindle 9 when the spindle 9 is placed in the forward position. The brake member 82 suppresses unnecessary rotation of the spindle 9. The brake member 82 is supported by the front housing 32. Brake member 82 is arranged around spindle bearing 48 . The circlip 61 is arranged between the brake member 82 and a portion of the front housing 32. The brake member 82 faces the flange portion 9B of the spindle 9. The spindle 9 has a front cam portion 9J that projects forward from the front surface of the flange portion 9B.

The brake member 82 includes a brake ring portion 82A supported by the front housing 32, a recess 82B provided in a part of the outer circumference of the brake ring portion 82A, and a brake cam portion protruding rearward from the rear surface of the brake ring portion 82A. 82C. A convex portion provided on the inner surface of the front housing 32 is arranged in a concave portion 82B of the brake member 82. Thereby, relative rotation between the front housing 32 and the brake member 82 is suppressed. A front cam portion 9J is provided on the front surface of the flange portion 9B of the spindle 9. When the spindle 9 is in the forward position, the spindle 9 comes into contact with the brake cam portion 82C of the brake member 82 and the front cam portion 9J of the spindle 9, and rotation of the spindle 9 is prevented.

The tool holding mechanism 10 holds the driver bit 30 inserted into the bit holding hole 9C. The tool holding mechanism 10 includes a ball 49 arranged in a through hole 9F that connects the outer peripheral surface of the spindle 9 and an inner peripheral surface of the bit holding hole 9C, and a leaf arranged outside the ball 49 in the radial direction of the rotation axis CX. and a spring 50. The ball 49 is pressed inward in the radial direction from the leaf spring 50. By disposing at least a portion of the ball 49 in the recess 30A provided in the driver bit 30, the driver bit 30 is prevented from coming off from the bit holding hole 9C.

The lock ring 11 is operated by an operator to adjust the amount of protrusion of the driver bit 30 from the front end surface of the rubber cap 13. The lock ring 11 is arranged around the cylindrical portion 32B of the front housing 32. The lock ring 11 is rotatable relative to the front housing 32. The lock ring 11 moves in the front-rear direction with respect to the front housing 32 by being rotated. A thread 32C is formed on the outer peripheral surface of the cylindrical portion 32B, and a thread groove 11A is formed on the inner peripheral surface of the lock ring 11. When the lock ring 11 is rotated, the thread 32C on the outer peripheral surface of the cylindrical portion 32B and the thread groove 11A on the inner peripheral surface of the lock ring 11 rotate relative to each other. Thereby, the lock ring 11 moves in the front-back direction while rotating. When the lock ring 11 is rotated in one direction, the amount of protrusion of the driver bit 30 increases. When the lock ring 11 is rotated in the other direction, the amount of protrusion of the driver bit 30 decreases. A leaf spring 51 is arranged between the lock ring 11 and the cylindrical portion 32B. The leaf spring 51 gives a click feeling to the rotated lock ring 11.

The adjustment sleeve 12 is detachably attached to the lock ring 11. The adjustment sleeve 12 is attached to the lock ring 11 via an O-ring 52. The adjustment sleeve 12 is arranged around the spindle 9 in front of the lock ring 11. Adjustment sleeve 12 is substantially cylindrical. The adjustment sleeve 12 has a tapered shape that decreases in diameter toward the front. The adjustment sleeve 12 moves forward and backward together with the lock ring 11 as the lock ring 11 rotates.

The rubber cap 13 is attached to the front end of the adjustment sleeve 12. The rubber cap 13 is fixed to the front end of the adjustment sleeve 12 via a cup washer 53. The rubber cap 13 is arranged around the driver bit 30 mounted on the spindle 9. In a screw tightening operation using the screwdriver 1, the rubber cap 13 comes into contact with the workpiece. The rubber cap 13 prevents the workpiece from being damaged.

The front end of the driver bit 30 inserted into the bit holding hole 9C and held by the tool holding mechanism 10 is located further forward than the front end of the rubber cap 13. When adjusting the tightening depth of the screw with respect to the workpiece, the operator rotates the lock ring 11 to move the lock ring 11 in the front-back direction. When the lock ring 11 moves in the front-rear direction, the adjustment sleeve 12 and the rubber cap 13 move in the front-rear direction together with the lock ring 11. Thereby, the amount of protrusion of the driver bit 30 from the front end surface of the rubber cap 13 is adjusted. By adjusting the amount of protrusion of the driver bit 30 from the front end surface of the rubber cap 13, the tightening depth of the screw against the workpiece is adjusted.

The trigger lever 14 is operated by an operator to start the motor 6. The trigger lever 14 is provided on the grip portion 22A. The trigger lever 14 projects forward from the upper front part of the grip part 22A. A switch 54 is arranged behind the trigger lever 14. The switch 54 is housed in the grip portion 22A. Trigger lever 14 is connected to switch 54. When the trigger lever 14 is pulled to move backward, an operation signal is output from the switch 54 to the controller 20. Controller 20 drives motor 6 based on the operation signal from switch 54 . When the trigger lever 14 is released, the motor 6 is stopped.

The lock button 15 is operated by the operator in order to maintain the state in which the trigger lever 14 is pulled. The lock button 15 is provided at the upper left portion of the grip portion 22A. By pressing the lock button 15 while the trigger lever 14 is pulled, the pulled state of the trigger lever 14 is maintained even if the operator releases the trigger lever 14, and the drive of the motor 6 is maintained. Ru.

The forward/reverse switching lever 16 is operated by an operator to switch the rotation direction of the motor 6. The forward/reverse switching lever 16 is provided at the connecting portion 22B. By operating the forward/reverse switching lever 16, the rotation direction of the motor 6 is switched from one of the forward rotation direction and the reverse rotation direction to the other. By switching the rotation direction of the motor 6, the rotation direction of the spindle 9 is switched. When the forward/reverse switching lever 16 is placed in the neutral position, the trigger lever 14 cannot be operated.

The light 17 emits illumination light. The light 17 includes a light emitting diode (LED). The light 17 is arranged at the lower front part of the connecting part 24. The light 17 illuminates the front of the spindle 9 with illumination light.

The switch plate 18 has a mode switching button 18A operated by an operator. The switch plate 18 is provided in the battery holding section 23. The switch plate 18 is provided on the upper surface of the battery holding part 23 between the lower end of the grip part 22A and the lower end of the connecting part 24. The operating mode of the motor 6 is switched by the operator operating the mode switching button 18A. In the embodiment, the operating modes of the motor 6 include a normal mode and a push drive mode. The normal mode is an operation mode in which the motor 6 is started by pulling the trigger lever 14. Push drive mode is an operation mode in which the motor 6 is not driven immediately even when the trigger lever 14 is pulled, but the motor 6 is started only after it is detected that the spindle 9 has moved backward from the forward position together with the driver bit 30. means. The operator can set the operating mode of the screwdriver 1 to either the normal mode or the push drive mode by operating the mode switching button 18A.

The push drive mechanism 19 operates so that when the operation mode of the motor 6 is set to the push drive mode, it is detected that the spindle 9 has moved backward from the forward position together with the driver bit 30.

The push drive mechanism 19 includes a rod 55, a seal 56, a lever 57, a torsion spring 58, a magnet 59, and a mode sensor board 60.

The rod 55 is arranged inside the through hole 74A provided in the intermediate shaft 74. The through hole 74A is formed to penetrate the front end surface and the rear end surface of the intermediate shaft 74. The through hole 74A is formed to include the central axis of the intermediate shaft 74. The rod 55 moves relative to the intermediate shaft 74 in the front-back direction. The front end of the rod 55 contacts the support surface 9E of the spindle 9. The rear end portion of the rod 55 projects rearward beyond the recess 31B through an opening provided in the recess 31B of the rear housing 31.

The seal 56 seals the boundary between the outer peripheral surface of the rod 55 and the inner peripheral surface of the through hole 74A of the intermediate shaft 74. A seal 56 is placed around the rod 55. Seal 56 is cylindrical. Seal 56 is fixed to the inner circumferential surface of intermediate shaft 74 . The seal 56 functions as a guide member that guides the rod 55 in the front-back direction.

The lever 57 is rotatably supported by the main body housing 2. The main body housing 2 has a pin portion 2B that rotatably supports the lever 57. The rotation axis of the lever 57 extends in the left-right direction. The lever 57 includes a rotating portion 57A disposed around the pin portion 2B, a first protruding portion 57B protruding downward from the rotating portion 57A, and a second protruding portion 57C protruding upward from the rotating portion 57A. has. The first protrusion 57B is arranged to face the rear end of the rod 55. The second protrusion 57C is arranged to face the mode sensor board 60. When the spindle 9 moves rearward from the forward position, the rod 55 is pushed by the spindle 9 and moves rearward. As the rod 55 moves rearward, the first protrusion 57B is pushed by the rod 55 and moves rearward. When the rod 55 moves rearward, the lever 57 rotates so that the first protrusion 57B moves rearward and the second protrusion 57C moves forward.

The torsion spring 58 is supported by the pin portion 2B. The torsion spring 58 applies elastic force to the lever 57 so that the first protrusion 57B moves forward and the second protrusion 57C moves rearward.

The magnet 59 is fixed to the second protrusion 57C.

Mode sensor board 60 includes a circuit board and a magnetic sensor supported by the circuit board. At least a portion of the mode sensor board 60 faces the magnet 59 fixed to the second protrusion 57C. The magnetic sensor detects the rotation state of the lever 57 by detecting changes in the magnetic field of the magnet 59. A detection signal from the magnetic sensor is transmitted to the controller 20 via a lead wire (not shown). The mode sensor board 60 is supported by support ribs 2C provided on the main body housing 2. The support rib 2C is arranged above the fan case portion 2A.

In the normal mode, the motor 6 is started by pulling the trigger lever 14. In the push drive mode, the motor 6 is started by pulling the trigger lever 14 and rotating the lever 57 so that the rod 55 moves backward and the magnet 59 separates from the mode sensor board 60.

Controller 20 outputs a control signal to control motor 6. Controller 20 is housed in battery holding section 23 . The controller 20 controls the motor 6 based on the operating mode of the motor 6 set by operating the mode switching button 18A. The controller 20 includes a circuit board 20A on which a plurality of electronic components are mounted, and a case 20B that houses the circuit board 20A. Electronic components mounted on the circuit board 20A include a processor such as a CPU (Central Processing Unit), a non-volatile memory such as a ROM (Read Only Memory) or a storage, a volatile memory such as a RAM (Random Access Memory), A transistor and a resistor are exemplified.

[Clutch mechanism]
The clutch mechanism 8A transmits the rotational force of the rotor 34 of the motor 6 to the spindle 9 when the spindle 9 moves to the backward position during normal rotation of the motor 6. The clutch mechanism 8A includes a drive cam portion 72C provided on the clutch cam 72, and a driven cam portion 9G provided on the spindle 9 so as to face the drive cam portion 72C. Clutch cam 72 is arranged around intermediate shaft 74 . Clutch cam 72 is coupled to drive gear 71 via balls 73. The clutch mechanism 8A also includes a compression spring 75 that biases the clutch cam 72 rearward and the spindle 9 forward.

The sleeve 76 is arranged inside the gear housing 3 radially outside of the drive cam section 72C and the driven cam section 9G. The sleeve 76 is arranged to surround each of the cam ring portion 72A of the clutch cam 72 and the flange portion 9B of the spindle 9. The rear part of the inner peripheral surface of the sleeve 76 contacts the rear O-ring 77. The front portion of the inner circumferential surface of the sleeve 76 contacts the front O-ring 78 . The stopper portion 76B of the sleeve 76 contacts the front surface of the gear portion 71B of the drive gear 71. The rear surface of the stopper portion 76B contacts the front surface of the gear portion 71B, thereby suppressing the sleeve 76 from moving rearward with respect to the drive gear 71.

When performing a screw tightening operation on a workpiece, the forward/reverse switching lever 16 is operated so that the rotor 34 of the motor 6 rotates in the forward direction. After the driver bit 30 is inserted into the bit holding hole 9C and the driver bit 30 is attached to the rod portion 9A, the operator grasps the handle portion 22 and touches the tip of the driver bit 30 to the surface of the workpiece. Insert into the cross groove of the head of the screw. Next, the operator pulls the trigger lever 14. In the normal mode, the motor 6 is started by pulling the trigger lever 14. When the motor 6 is started and the rotor 34 rotates forward, the rotation of the rotor shaft 41 is transmitted to the drive gear 71 via the pinion gear 47. When the drive gear 71 is rotated by the motor 6, the clutch cam 72 coupled to the drive gear 71 via the ball 73 rotates together with the drive gear 71. By disposing the ball 73 at one end of the cam ball groove 72D in the circumferential direction, relative rotation between the drive gear 71 and the clutch cam 72 is suppressed. Further, the intermediate shaft 74 rotates together with the drive gear 71.

When the spindle 9 is placed in the forward position, even if the drive gear 71 rotates, the drive cam section 72C and the driven cam section 9G are separated, so the rotational force is not directly transmitted from the clutch cam 72 to the spindle 9. is not transmitted. When the spindle 9 is placed in the forward position, the clutch cam 72 and the spindle 9 are connected via the rear O-ring 77, the sleeve 76, and the front O-ring 78. Therefore, the rotational force of the clutch cam 72 is transmitted to the spindle 9 via the rear O-ring 77, the sleeve 76, and the front O-ring 78. Due to the friction between the sleeve 76 and the rear O-ring 77 and the friction between the sleeve 76 and the front O-ring 78, the rotational force of the clutch cam 72 is transferred to the spindle 9 via the rear O-ring 77, the sleeve 76, and the front O-ring 78. is transmitted to.

However, even if the rotational force of the clutch cam 72 is transmitted to the spindle 9 via the sleeve 76 when the spindle 9 is placed in the forward position, the front cam portion 9J and the brake cam portion 82C are in contact with each other. Therefore, the rotation of the spindle 9 is prevented by the brake member 82. Since unnecessary rotation of the spindle 9 is suppressed, the operator can smoothly insert the tip of the driver bit 30 into the cross groove of the head of the screw.

With the drive gear 71 and the clutch cam 72 rotating, the operator grips the handle portion 22 and performs a pushing operation to push the screwdriver 1 so that it approaches the workpiece. Due to the pushing operation of the screwdriver 1, the spindle 9 together with the driver bit 30 moves rearward against the elastic force of the compression spring 75.

When the spindle 9 moves from the forward position to an intermediate position between the forward position and the backward position, the front cam part 9J and the brake cam part 82C are separated, and the prevention of rotation of the spindle 9 by the brake member 82 is released. Ru. Rotation of the spindle 9 is started when the spindle 9 moves from the forward position to the intermediate position. When the spindle 9 is disposed at the intermediate position, the front cam portion 9J and the brake cam portion 82C are separated from each other, and the drive cam portion 72C and the driven cam portion 9G are separated from each other. When the spindle 9 is in the intermediate position, the spindle 9 is rotated by the rotational force of the clutch cam 72 transmitted via the rear O-ring 77, the sleeve 76, and the front O-ring 78.

At the intermediate position, the spindle 9 rotates due to the friction between the sleeve 76 and the rear O-ring 77 and the friction between the sleeve 76 and the front O-ring 78. Since the rotational force of the clutch cam 72 is transmitted to the spindle 9 by friction, the spindle 9 has a rotational speed lower than the rotational speed of the clutch cam 72 when the driving cam portion 72C and the driven cam portion 9G are separated from each other. Rotate with. Thereby, the spindle 9 can move toward the retreat position while rotating at a rotational speed lower than the rotational speed of the clutch cam 72. The spindle 9 moves toward the retreat position while rotating at a rotational speed of, for example, 20% or more and 30% or less of the rotational speed of the clutch cam 72.

When the spindle 9 moves to the retreat position, the drive cam portion 72C and the driven cam portion 9G come into contact. Since the spindle 9 moves toward the retreat position while rotating due to the rotational force of the clutch cam 72 transmitted through the sleeve 76, compared to the case where the spindle 9 does not rotate and moves toward the retreat position, The relative rotational speed between the clutch cam 72 and the spindle 9 becomes low when the drive cam portion 72C and the driven cam portion 9G contact each other. Therefore, the impact when the drive cam portion 72C and the driven cam portion 9G come into contact is reduced. Therefore, generation of noise due to contact between the drive cam portion 72C and the driven cam portion 9G is suppressed.

When the spindle 9 moves from the forward position to the backward position and the driving cam part 72C and the driven cam part 9G come into contact, the clutch cam 72 receives a resistance force in the rotational direction from the spindle 9, and as a result, the ball 73 moves into the gear ball groove. The drive gear 71 and the clutch cam 72 rotate relative to each other via the ball 73 by rolling between the ball 71D and the cam ball groove 72D. By moving the ball 73 in the circumferential direction from one end of the cam ball groove 72D to the other end and stopping at the other end of the cam ball groove 72D, the drive gear 71 and the clutch cam 72 can rotate together. . As shown in FIG. 13, in the embodiment, at least a part of the cam ball groove 72D is inclined in the front-rear direction, so the drive cam part 72C and the driven cam part 9G come into contact with each other, so that the drive gear 71 and the clutch cam The clutch cam 72 moves forward as the clutch cam 72 rotates relative to the clutch cam 72 via the ball.

When the clutch cam 72 moves forward and the motor 6 is driven with the drive cam section 72C and the driven cam section 9G in contact with each other, the spindle 9 is moved to a clutch mechanism including the drive cam section 72C and the driven cam section 9G. It is rotated by the rotational force of the clutch cam 72 transmitted through the clutch cam 8A. By rotating the driver bit 30 in the normal direction together with the spindle 9, the screw is screwed into the workpiece.

In the screw tightening work, the operator continues pushing the screwdriver 1. The sleeve 76 has a stopper portion 76B that contacts the front surface of the drive gear 71. Therefore, even if the spindle 9 moves from the forward position to the retreat position due to the pushing operation, the sleeve 76 is prevented from moving rearward together with the spindle 9.

As the screw tightening work progresses, the screwdriver 1 gradually approaches the workpiece, and eventually the front end of the rubber cap 13 comes into contact with the workpiece. After the front end of the rubber cap 13 comes into contact with the workpiece, the spindle 9 rotates and moves forward as the screw tightening operation progresses. At the beginning of the screw tightening operation, the torque applied from the screw to the spindle 9 via the driver bit 30 is large, but at the end of the screw tightening operation, the torque applied from the screw to the spindle 9 via the driver bit 30 decreases. When the torque applied to the spindle 9 via the driver bit 30 decreases, the contact force between the drive cam portion 72C and the driven cam portion 9G decreases. When the contact force between the drive cam portion 72C and the driven cam portion 9G decreases, the clutch cam 72 moves rearward due to the urging force of the compression spring 75. As a result, the driving cam portion 72C and the driven cam portion 9G are separated from each other, and the rotation of the spindle 9 is stopped. With the above steps, the screw tightening work is completed.

Even if the drive cam part 72C and the driven cam part 9G are separated and the spindle 9 stops rotating, the motor 6 continues to be driven while the trigger lever 14 is being pulled. When the trigger lever 14 is released, the motor 6 is stopped. When the pushing operation is released and the driver bit 30 is separated from the screw, the spindle 9 returns to the forward position due to the biasing force of the compression spring 75. When the spindle 9 returns to the forward position, the brake cam portion 82C of the brake member 82 and the front cam portion 9J of the spindle 9 come into contact, and unnecessary rotation of the spindle 9 is prevented.

Note that in the push drive mode, the motor 6 is not activated simply by pulling the trigger lever 14. When the spindle 9 moves rearward by the pushing operation of the screwdriver 1 with the trigger lever 14 being pulled, the rod 55 in contact with the support surface 9E of the spindle 9 moves rearward. When the rod 55 moves backward, the lever 57 rotates so that the magnet 59 separates from the mode sensor board 60. The controller 20 starts the motor 6 based on the change in the magnetic field detected by the mode sensor board 60. When the motor 6 is started, the clutch cam 72 starts rotating. When the spindle 9 is disposed at the intermediate position, the brake cam section 82C and the front cam section 9J are separated, and when the drive cam section 72C and the driven cam section 9G are separated, the spindle 9 moves the sleeve 76. The clutch cam 72 is rotated by the rotational force of the clutch cam 72 transmitted through the clutch cam 72 . As the pushing operation continues, the spindle 9 rotates and moves toward the retracted position. When the spindle 9 moves to the retreat position and the drive cam section 72C and the driven cam section 9G come into contact with each other, the spindle 9 is transferred via the clutch mechanism 8A including the drive cam section 72C and the driven cam section 9G. It rotates due to the rotational force of the clutch cam 72. By rotating the driver bit 30 in the normal direction together with the spindle 9, the screw is screwed into the workpiece.

As the screw tightening work progresses, the screwdriver 1 gradually approaches the workpiece, and eventually the front end of the rubber cap 13 comes into contact with the workpiece. When the torque applied to the spindle 9 via the driver bit 30 decreases, the clutch cam 72 moves rearward due to the biasing force of the compression spring 75. As a result, the driving cam portion 72C and the driven cam portion 9G are separated from each other, and the rotation of the spindle 9 is stopped. With the above steps, the screw tightening work is completed.

When the screw tightening operation is completed, the pushing operation is released, and the driver bit 30 is separated from the screw, the spindle 9 returns to the forward position by the biasing force of the compression spring 75. When the spindle 9 returns to the forward position, the brake cam portion 82C of the brake member 82 and the front cam portion 9J of the spindle 9 come into contact, and unnecessary rotation of the spindle 9 is prevented.
Further, when the spindle 9 returns to the forward position, the lever 57 is rotated by the elastic force of the torsion spring 58 so that the magnet 59 approaches the mode sensor board 60. The controller 20 stops the motor 6 based on the change in the magnetic field detected by the mode sensor board 60.

[Spindle lock mechanism]
The spindle lock mechanism 8B transmits the rotational force of the rotor 34 of the motor 6 to the spindle 9 when the motor 6 rotates in reverse. The front part of the intermediate shaft 74 is accommodated in the accommodation hole 9D of the spindle 9. A rear portion of intermediate shaft 74 is coupled to drive gear 71 . The intermediate shaft 74 is rotated by the rotor 34 around the rotation axis CX. The spindle lock mechanism 8B is arranged at the boundary between the intermediate shaft 74 and the spindle 9.

A pin support portion 74E is defined at the front of the intermediate shaft 74 inserted into the accommodation hole 9D. As described with reference to FIG. 18, the pin support portion 74E has a large diameter portion 74K and a small diameter portion 74J provided at a position different from the large diameter portion 74K in the circumferential direction. The radial distance LK between the rotation axis CX and the outer peripheral surface of the large diameter portion 74K is larger than the radial distance LJ between the rotation axis CX and the outer peripheral surface of the small diameter portion 74J.

The spindle lock mechanism 8B has a lock pin 79 arranged around the pin support part 74E. When the rotor 34 rotates in reverse, the lock pin 79 is sandwiched between the outer circumferential surface of the large diameter portion 74K and the inner circumferential surface of the accommodation hole 9D. The intermediate shaft 74 and the spindle 9 are locked by the lock pin 79, which is sandwiched between the outer circumferential surface of the large diameter portion 74K and the inner circumferential surface of the accommodation hole 9D. That is, the lock pin 79 functions as a wedge that locks the intermediate shaft 74 and the spindle 9 and prevents relative rotation between the intermediate shaft 74 and the spindle 9. When the rotor 34 is reversed, the intermediate shaft 74 and the spindle 9, which are locked by the lock pin 79, do not rotate relative to each other but rotate together. When the rotor 34 is reversed, the intermediate shaft 74 and the spindle 9 rotate together due to the wedge effect of the lock pin 79, so that the rotation of the drive gear 71 is controlled via the spindle lock mechanism 8B including the intermediate shaft 74 and the lock pin 79. is transmitted to the spindle 9.

Note that when the rotor 34 rotates normally, the lock pin 79 is arranged between the outer peripheral surface of the small diameter portion 74J and the inner peripheral surface of the accommodation hole 9D. When the rotor 34 rotates normally, the wedge effect of the lock pin 79 is not exhibited. When the rotor 34 rotates normally, the intermediate shaft 74 and the spindle 9 can rotate relative to each other.

The intermediate shaft 74 is disposed at the rear end of the pin support portion 74E and has a stop surface 74G facing the rear end surface of the lock pin 79. The spindle lock mechanism 8B includes a compression spring 81 that biases the lock pin 79 rearward so that the rear end surface of the lock pin 79 is pressed against the stop surface 74G.

Further, the spindle lock mechanism 8B includes a sleeve 80 that contacts the front end surface of the lock pin 79. The rear end of the compression spring 81 is connected to the front surface of the sleeve 80. A front end of the compression spring 81 is connected to a support surface 9E disposed at the front of the accommodation hole 9D. Compression spring 81 biases lock pin 79 rearward via sleeve 80.

The spindle lock mechanism 8B is provided on the inner peripheral surface of the accommodation hole 9D, and has a pin groove 9L in which at least a portion of the lock pin 79 is disposed. The pin groove 9L is long in the front-rear direction. The rear end of the pin groove 9L is disposed further forward than the rear end of the accommodation hole 9D. As shown in FIG. 22, a plurality of pin grooves 9L are provided in the circumferential direction on the inner peripheral surface of the accommodation hole 9D. A plurality of pin grooves 9L are provided at equal intervals in the circumferential direction. On the rear surface of the spindle 9, a cylindrical portion 9M is provided inside the groove 9K in the radial direction. The inner circumferential surface of the rear end portion of the cylindrical portion 9M includes an inclined surface 9N that slopes radially outward toward the rear. As shown in FIGS. 5 and 7, the front end portion of the compression spring 75 is arranged around the cylindrical portion 9M.

The lock pin 79 is disposed between the outer circumferential surface of the small diameter portion 74J and the inner circumferential surface of the accommodation hole 9D, so that it is removed from the pin groove 9L.

The lock pin 79 is inserted from the pin groove 9L when the spindle 9 is placed in the forward position with the lock pin 79 placed between the outer peripheral surface of the large diameter portion 74K and the inner peripheral surface of the accommodation hole 9D. It comes off. A raised portion 74M is provided at the rear of the outer peripheral surface of the pin support portion 74E. When the spindle 9 is placed in the forward position with the lock pin 79 disposed between the outer peripheral surface of the large diameter portion 74K and the inner peripheral surface of the accommodation hole 9D, the raised portion 74M and the lock pin 79 are Contact. Due to the contact between the raised portion 74M and the lock pin 79, the lock pin 79 moves in the radial direction so as to be removed from the pin groove 9L.

The lock pin 79 is disposed in the pin groove 9L when the spindle 9 moves to the retreat position with the lock pin 79 disposed between the outer circumferential surface of the large diameter portion 74K and the inner circumferential surface of the accommodation hole 9D. be done.

In the embodiment, the lock pin 79 is disposed between the outer circumferential surface of the large diameter portion 74K and the inner circumferential surface of the accommodation hole 9D, and is also disposed in the pin groove 9L, so that the intermediate shaft 74 and the spindle 9 can be connected to each other. is locked by a lock pin 79. Even if the lock pin 79 is disposed between the outer circumferential surface of the large diameter portion 74K and the inner circumferential surface of the accommodation hole 9D, if it comes off the pin groove 9L, the intermediate shaft 74 and the spindle 9 will not be locked.

When performing a screw tightening operation for tightening a screw into a workpiece, the motor 6 is rotated in the normal direction. When performing a screw removal operation in which a screw is removed from a workpiece, the motor 6 is reversed. In each of screw tightening work and screw removal work, push the screw driver 1 so that it approaches the workpiece with the tip of the driver bit 30 inserted into the cross groove of the head of the screw. Action is performed. The push-in action moves the spindle 9 from the forward position to the retracted position. In the embodiment, the spindle lock mechanism 8B transmits the rotational force of the rotor 34 to the spindle 9 when the spindle 9 moves to the retracted position. That is, in the embodiment, when the spindle 9 is moved to the retreat position by a pushing operation when the rotor 34 is reversed, the intermediate shaft 74 and the spindle 9 are locked by the lock pin 79.

FIG. 23 is a sectional view showing a part of the screwdriver 1 when the rotor 34 is rotated normally and no pushing operation is being performed. FIG. 24 is an enlarged view of portion B in FIG. 23. FIG. 25 is a cross-sectional view taken along line HH in FIG. 24. FIG. 26 is an enlarged view of portion C in FIG. 25.

FIG. 27 is a sectional view showing a part of the screwdriver 1 when the rotor 34 is rotated normally and a pushing operation is performed. In FIG. 27, although the driver bit 30 is pushed in, the clutch mechanism 8A is not engaged. FIG. 28 is an enlarged view of portion B in FIG. 27. FIG. 29 is a cross-sectional view taken along line HH in FIG. 28. FIG. 30 is an enlarged view of portion C in FIG. 29.

FIG. 31 is a sectional view showing a part of the screwdriver 1 when the rotor 34 is reversed and no pushing operation is performed. FIG. 32 is an enlarged view of portion B in FIG. 31. FIG. 33 is a cross-sectional view taken along line HH in FIG. 31. FIG. 34 is an enlarged view of portion C in FIG. 33.

FIG. 35 is a sectional view showing a part of the screwdriver 1 when the rotor 34 is reversed and a pushing operation is performed. In FIG. 35, although the driver bit 30 is pushed in, the clutch mechanism 8A is not engaged. FIG. 36 is an enlarged view of portion B in FIG. 35. FIG. 37 is a cross-sectional view taken along line HH in FIG. 36. FIG. 38 is an enlarged view of portion C in FIG. 37.

As shown in FIGS. 23 to 26, when the rotor 34 rotates normally, the lock pin 79 is disposed between the outer circumferential surface of the small diameter portion 74J and the inner circumferential surface of the accommodation hole 9D. Further, since the pushing operation is not performed, the spindle 9 is placed in the forward position. The lock pin 79 comes off from the pin groove 9L when it is disposed between the outer peripheral surface of the small diameter portion 74J and the inner peripheral surface of the accommodation hole 9D. Since the lock pin 79 is disposed between the outer peripheral surface of the small diameter portion 74J and the inner peripheral surface of the accommodation hole 9D and is out of the pin groove 9L, the intermediate shaft 74 and the spindle 9 are not locked and rotate relative to each other. Can be done. The lock pin 79 contacts the convex portion 74H. When the intermediate shaft 74 rotates normally inside the spindle 9, the lock pin 79 rotates around the rotation axis CX inside the spindle 9 while being pushed by the convex portion 74H.

As shown in FIGS. 27 to 30, when the rotor 34 rotates normally, the lock pin 79 is disposed between the outer circumferential surface of the small diameter portion 74J and the inner circumferential surface of the accommodation hole 9D. Since the push-in operation is being performed, the spindle 9 is placed in the retracted position. Since the lock pin 79 is disposed between the outer peripheral surface of the small diameter portion 74J and the inner peripheral surface of the accommodation hole 9D, it comes off from the pin groove 9L. Since the lock pin 79 is disposed between the outer peripheral surface of the small diameter portion 74J and the inner peripheral surface of the accommodation hole 9D and is out of the pin groove 9L, the intermediate shaft 74 and the spindle 9 are not locked and rotate relative to each other. Can be done. The lock pin 79 contacts the convex portion 74H. When the intermediate shaft 74 rotates normally inside the spindle 9, the lock pin 79 rotates around the rotation axis CX inside the spindle 9 while being pushed by the convex portion 74H.

As shown in FIGS. 31 to 34, when the rotor 34 is reversed, the lock pin 79 is disposed between the outer circumferential surface of the large diameter portion 74K and the inner circumferential surface of the accommodation hole 9D. Further, since the pushing operation is not performed, the spindle 9 is placed in the forward position. As shown in FIG. 32, the rear end portion of the lock pin 79 is arranged rearward than the rear end portion of the accommodation hole 9D. Due to the contact between the raised portion 74M and the rear end portion of the lock pin 79, the lock pin 79 moves in the radial direction so as to be removed from the pin groove 9L, as shown in FIG. In the example shown in FIG. 32, the locking pin 79 slopes radially outward toward the rear. Although the lock pin 79 is disposed between the outer peripheral surface of the large diameter portion 74K and the inner peripheral surface of the accommodation hole 9D, it is out of the pin groove 9L, so the intermediate shaft 74 and the spindle 9 are not locked. , can be rotated relative to each other. When the rotor 34 is reversed and the pushing operation is not being performed, the intermediate shaft 74 and the spindle 9 are not locked, so the spindle 9 does not rotate.

As shown in FIGS. 35 to 38, when the rotor 34 is reversed, the lock pin 79 is disposed between the outer circumferential surface of the large diameter portion 74K and the inner circumferential surface of the accommodation hole 9D. Further, since the pushing operation is being performed, the spindle 9 is placed in the retracted position. The lock pin 79 is disposed in the pin groove 9L when the spindle 9 moves to the retreat position with the lock pin 79 disposed between the outer circumferential surface of the large diameter portion 74K and the inner circumferential surface of the accommodation hole 9D. Ru. Since the lock pin 79 is disposed between the outer circumferential surface of the large diameter portion 74K and the inner circumferential surface of the accommodation hole 9D, and is also disposed in the pin groove 9L, the intermediate shaft 74 and the spindle 9 are locked together. can be rotated. When the push-in operation is performed during the rotation of the rotor 34, the intermediate shaft 74 and the spindle 9 rotate in rotation together. As a result, the screw removal operation is performed.

Note that by placing the spindle 9 in the retracted position, there is a possibility that the position of the drive cam part 72C and the position of at least part of the driven cam part 9G overlap in the front-rear direction. In the embodiment, even if the position of the drive cam part 72C and the position of at least part of the driven cam part 9G overlap in the front-rear direction, the intermediate shaft is arranged so that the drive cam part 72C and the driven cam part 9G do not come into contact with each other. 74 and spindle 9 are locked. That is, even if the position of the drive cam part 72C and the position of at least part of the driven cam part 9G overlap in the front-rear direction, the drive cam part 72C and the driven cam part 9G are arranged at shifted positions in the circumferential direction. Thus, the intermediate shaft 74 and spindle 9 are locked.

[effect]
As explained above, in the embodiment, the screwdriver 1 includes the gear housing 3, the motor 6, the clutch cam 72 arranged inside the gear housing 3, and the spindle 9 arranged ahead of the clutch cam 72. and. Clutch cam 72 is rotated by motor 6 around rotation axis CX. The spindle 9 has a driven cam portion 9G facing a driving cam portion 72C provided on the clutch cam 72, and a rod portion 9A to which the driver bit 30 is attached. The spindle 9 is supported by the gear housing 3 so as to be movable in the front-back direction so that the drive cam part 72C and the driven cam part 9G come into contact with each other or are separated from each other. The screwdriver 1 includes a sleeve 76 that is disposed inside the gear housing 3 and radially outward of the drive cam section 72C and the driven cam section 9G.

In the above configuration, the sleeve 76 is disposed inside the gear housing 3 on the radially outer side of the drive cam part 72C and the driven cam part 9G of the clutch mechanism 8A, so that the sleeve 76 is not coated on the drive cam part 72C and the driven cam part 9G. This prevents lubricant such as grease from scattering around the sleeve 76. As a result, the state in which the lubricant is applied to the drive cam portion 72C and the driven cam portion 9G is maintained, and a decrease in lubricant in the clutch mechanism 8A is suppressed. Therefore, wear of the drive cam portion 72C and the driven cam portion 9G is suppressed, and the life of the screwdriver 1 is suppressed from becoming short. Further, the sleeve 76 suppresses noise generated when the drive cam portion 72C and the driven cam portion 9G come into contact with each other from being transmitted to the surroundings of the screwdriver 1.

In the embodiment, the clutch cam 72 has a cam ring portion 72A arranged around the rotation axis CX. The drive cam portion 72C is provided so as to protrude forward from the front surface of the cam ring portion 72A. The spindle 9 has a flange portion 9B provided at the rear end of the rod portion 9A. The driven cam portion 9G is provided so as to protrude rearward from the rear surface of the flange portion 9B. The sleeve 76 is supported by the cam ring part 72A and the flange part 9B, respectively.

In the above configuration, each of the driving cam part 72C and the driven cam part 9G is arranged inside the closed space defined by the cam ring part 72A, the flange part 9B, and the sleeve 76. Therefore, the lubricant applied to the drive cam portion 72C and the driven cam portion 9G is effectively prevented from scattering around the sleeve 76. Furthermore, the sleeve 76 effectively suppresses noise generated when the drive cam portion 72C and the driven cam portion 9G come into contact with each other from being transmitted to the surroundings of the screwdriver 1.

In the embodiment, the screwdriver 1 includes a front O-ring 78 that is arranged on the outer periphery of the flange portion 9B and contacts the sleeve 76.

In the above configuration, the front O-ring 78 seals the boundary between the sleeve 76 and the flange portion 9B. This effectively prevents the lubricant applied to the drive cam portion 72C and the driven cam portion 9G from scattering around the sleeve 76. Furthermore, transmission of noise to the surroundings of the screwdriver 1 when the drive cam portion 72C and the driven cam portion 9G come into contact is effectively suppressed.

In the embodiment, the screwdriver 1 includes a rear O-ring 77 that is arranged on the outer circumference of the cam ring portion 72A and contacts the sleeve 76.

In the above configuration, the boundary between the sleeve 76 and the cam ring portion 72A is sealed by the rear O-ring 77. This effectively prevents the lubricant applied to the drive cam portion 72C and the driven cam portion 9G from scattering around the sleeve 76. Furthermore, transmission of noise to the surroundings of the screwdriver 1 when the drive cam portion 72C and the driven cam portion 9G come into contact is effectively suppressed.

In the embodiment, the drive cam portion 72C and the driven cam portion 9G are separated from each other when the spindle 9 is placed in the forward position. The drive cam portion 72C and the driven cam portion 9G can come into contact with each other in a state where the spindle 9 is disposed at the retracted position rearward than the forward position. With the spindle 9 in the forward position, the rotational force of the clutch cam 72 is transmitted to the spindle 9 via the sleeve 76.

In the above configuration, the rotational force of the clutch cam 72 is transferred to the rear O-ring 77, the sleeve 76, and the front O-ring 78 due to the friction between the sleeve 76 and the rear O-ring 77 and the friction between the sleeve 76 and the front O-ring 78. is transmitted to the spindle 9 via. The spindle 9 rotates due to friction between the sleeve 76 and the rear O-ring 77 and friction between the sleeve 76 and the front O-ring 78. Since the rotational force of the clutch cam 72 is transmitted to the spindle 9 by friction, the spindle 9 has a rotational speed lower than the rotational speed of the clutch cam 72 when the driving cam portion 72C and the driven cam portion 9G are separated from each other. Rotate with. Thereby, the spindle 9 can move toward the retreat position while rotating at a rotational speed lower than the rotational speed of the clutch cam 72. Since the spindle 9 moves toward the retreat position while rotating due to the rotational force of the clutch cam 72 transmitted through the sleeve 76, compared to the case where the spindle 9 does not rotate and moves toward the retreat position, The relative rotational speed between the clutch cam 72 and the spindle 9 becomes low when the drive cam portion 72C and the driven cam portion 9G contact each other. Therefore, the impact when the drive cam portion 72C and the driven cam portion 9G come into contact is reduced. Therefore, generation of noise due to contact between the drive cam portion 72C and the driven cam portion 9G is suppressed.

In the embodiment, the screwdriver 1 includes a brake member 82 that is supported by the gear housing 3 and prevents rotation of the spindle 9 when the spindle 9 is placed in the forward position.

In the above configuration, even if the rotational force of the clutch cam 72 is transmitted to the spindle 9 through the sleeve 76 when the spindle 9 is placed in the forward position, the rotation of the spindle 9 is prevented by the brake member 82. Ru. Since unnecessary rotation of the spindle 9 is suppressed, the operator can smoothly insert the tip of the driver bit 30 into the cross groove of the head of the screw, for example.

In the embodiment, the spindle 9 has a front cam portion 9J that projects forward from the front surface of the flange portion 9B. The brake member 82 includes a brake ring portion 82A supported by the gear housing 3, and a brake cam portion 82C that contacts the front cam portion 9J when the spindle 9 is in the forward position.

In the above configuration, rotation of the spindle 9 is prevented by contact between the front cam portion 9J of the flange portion 9B and the brake cam portion 82C of the brake member 82.

In the embodiment, when the spindle 9 moves from the forward position to an intermediate position between the forward position and the retracted position, rotation is no longer blocked by the brake member 82 and the spindle 9 starts rotating.

In the above configuration, rotation of the spindle 9 is started at an intermediate position before the spindle 9 moves to the retracted position. Since the spindle 9 is rotating when it moves from the intermediate position to the retreat position, the relative rotational speed between the clutch cam 72 and the spindle 9 when the drive cam part 72C and the driven cam part 9G come into contact becomes low. . Therefore, the impact when the drive cam portion 72C and the driven cam portion 9G come into contact is reduced. Therefore, generation of noise due to contact between the drive cam portion 72C and the driven cam portion 9G is suppressed.

In the embodiment, the screwdriver 1 includes a drive gear 71 that is at least partially disposed behind the clutch cam 72 and rotated by the motor 6 around the rotation axis CX. Clutch cam 72 is supported by drive gear 71. The sleeve 76 includes a cylindrical portion 76A disposed around each of the cam ring portion 72A and the flange portion 9B, and a stopper portion 76B that contacts the front surface of the drive gear 71.

In the above configuration, when the spindle 9 moves from the forward position to the retracted position, the sleeve 76 may move rearward together with the spindle 9 due to friction between the sleeve 76 and the front O-ring 78, for example. Since the sleeve 76 has a stopper portion 76B that contacts the front surface of the drive gear 71, even if the spindle 9 moves backward, the sleeve 76 is prevented from moving backward together with the spindle 9.

In the embodiment, the clutch cam 72 has a cam ball groove 72D provided on the rear surface of the cam ring portion 72A. The cam ball groove 72D has an arc shape in a plane perpendicular to the rotation axis CX. At least a portion of the cam ball groove 72D is inclined in the front-rear direction. The screwdriver 1 includes a ball 73 arranged in a cam ball groove 72D. Clutch cam 72 is coupled to drive gear 71 via balls 73. When the drive cam portion 72C and the driven cam portion 9G come into contact, the clutch cam 72 moves forward.

In the above configuration, the clutch cam 72 can rotate together with the drive gear 71 when the spindle 9 is placed in the forward position and the drive cam section 72C and the driven cam section 9G are separated from each other. When the spindle 9 moves from the forward position to the backward position and the driving cam part 72C and the driven cam part 9G come into contact, the clutch cam 72 receives a resistance force in the rotational direction from the spindle 9, and as a result, the balls 73 move into the cam ball groove. 72D, the drive gear 71 and clutch cam 72 rotate relative to each other via the ball 73. Since at least a portion of the cam ball groove 72D is inclined in the front-rear direction, the clutch cam 72 can be moved forward by relative rotation between the drive gear 71 and the clutch cam 72 via the balls.

In the embodiment, the screwdriver 1 includes a compression spring 75 that is disposed radially inside the sleeve 76 and biases the clutch cam 72 rearward. When the torque applied to the rotating spindle 9 due to the rotational force of the clutch cam 72 transmitted via the drive cam portion 72C and the driven cam portion 9G decreases, the clutch cam 72 is moved rearward by the compression spring 75, and the drive cam 72 is moved rearward by the compression spring 75. The cam portion 72C and the driven cam portion 9G are separated.

In the above configuration, at the beginning of a screw tightening operation using the screwdriver 1, the spindle 9 is pushed rearward via the driver bit 30, and the spindle 9 moves from the forward position to the backward position. When the spindle 9 moves from the forward position to the backward position, the drive cam part 72C and the driven cam part 9G come into contact, and the clutch cam 72 moves forward. At the end of the screw tightening work by the screwdriver 1, the torque applied to the spindle 9 via the driver bit 30 decreases, so the contact force between the drive cam portion 72C and the driven cam portion 9G decreases. When the contact force between the drive cam portion 72C and the driven cam portion 9G decreases, the compression spring 75 causes the clutch cam 72 to move rearward. As a result, the driving cam portion 72C and the driven cam portion 9G are separated from each other, and the rotation of the spindle 9 is stopped.

[Other embodiments]
In the embodiment described above, the sleeve 76 was in contact with the rear O-ring 77. The rear O-ring 77 may be omitted. A rear end portion of the inner peripheral surface of the sleeve 76 may contact the cam ring portion 72A of the clutch cam 72. Further, the rear end portion of the inner peripheral surface of the sleeve 76 may be fixed to the cam ring portion 72A.

[Other embodiments]
In the embodiments described above, the sleeve 76 was in contact with the front O-ring 78. The front O-ring 78 may be omitted. The front end of the inner peripheral surface of the sleeve 76 may contact the flange portion 9B of the spindle 9 so as to be relatively movable. Further, the sleeve 76 may be formed of a sealing member. Furthermore, an elastic body without sealing properties may be placed in place of the front O-ring 78.

In the embodiment described above, the intermediate shaft 74 and the spindle 9 are locked when the spindle 9 moves to the retreat position when the rotor 34 is reversed. The intermediate shaft 74 and the spindle 9 may be locked when the spindle 9 is placed in the forward position when the rotor 34 is reversed. That is, when the spindle 9 is placed in the forward position with the lock pin 79 disposed between the outer peripheral surface of the large diameter portion 74K and the inner peripheral surface of the accommodation hole 9D, the lock pin 79 is inserted into the pin groove. It may be placed in 9L.

In the above-described embodiment, when the pin groove 9L is not provided, the lock pin 79 is disposed between the outer circumferential surface of the large diameter portion 74K and the inner circumferential surface of the accommodation hole 9D, so that the intermediate shaft 74 and The spindle 9 is locked by the lock pin 79, and the lock pin 79 is disposed between the outer peripheral surface of the small diameter portion 74J and the inner peripheral surface of the accommodation hole 9D, so that the intermediate shaft 74 and the spindle 9 are not locked. You can also use it as

In the above-described embodiment, the spindle lock mechanism 8B includes the intermediate shaft 74 rotated by the rotor 34, the cylindrical portion 9P of the spindle 9 disposed around the intermediate shaft 74, and the outer peripheral surface of the intermediate shaft 74 and the cylindrical portion 9P. It has a lock pin 79 disposed between the lock pin 79 and the inner circumferential surface of the cylindrical portion 9P, and a pin groove 9L provided on the inner circumferential surface of the cylindrical portion 9P in which at least a portion of the lock pin 79 is disposed. did. That is, the spindle lock mechanism 8B is arranged at the boundary between the intermediate shaft 74 and the cylindrical portion 9P of the spindle 9. The spindle lock mechanism 8B only needs to be interposed between the rotor 34 and the spindle 9, and may be arranged at a position different from the boundary between the intermediate shaft 74 and the cylindrical portion 9P of the spindle 9. For example, a cylindrical part is arranged around the rotor shaft 41 of the motor 6, a pin groove is provided on the inner peripheral surface of the cylindrical part, and a gap is formed between the outer peripheral surface of the rotor shaft 41 and the inner peripheral surface of the cylindrical part. A locking pin may be disposed at.

In the embodiment described above, the power source of the screwdriver 1 may not be the battery pack 25, but may be a commercial power source (AC power source).

1...Screwdriver, 2...Main housing, 2A...Fan case part, 2B...Pin part, 2C...Support rib, 2L...Left side housing, 2R...Right side housing, 2S...Screw, 3...Gear housing, 3C...Seal ring, 3S...screw, 4...hook, 4S...screw, 5...battery attachment part, 6...motor, 7...fan, 8...power transmission mechanism, 8A...clutch mechanism, 8B...spindle lock mechanism, 9...spindle, 9A...rod 9B...Flange part, 9C...Bit holding hole, 9D...Accommodating hole, 9E...Supporting surface, 9F...Through hole, 9G...Followed cam part, 9H...Ring groove, 9J...Front cam part, 9K...Groove, 9L ... Pin groove, 9M... Cylindrical part, 9N... Inclined surface, 9P... Cylindrical part, 10... Tool holding mechanism, 11... Lock ring, 11A... Thread groove, 12... Adjustment sleeve, 13... Rubber cap, 14... Trigger lever , 15...Lock button, 16...Forward/reverse switching lever, 17...Light, 18...Switch plate, 18A...Mode switching button, 19...Push drive mechanism, 20...Controller, 20A...Circuit board, 20B...Case, 21...Motor Accommodating part, 21A... Recessed part, 22... Handle part, 22A... Grip part, 22B... Connecting part, 23... Battery holding part, 24... Connecting part, 25... Battery pack, 26... Intake port, 27... Exhaust port, 28... Hand strap, 29... Sleeve, 30... Driver bit, 30A... Recess, 31... Rear housing, 31A... Plate part, 31B... Recess, 31C... Cylindrical part, 32... Front housing, 32A... Plate part, 32B... Cylindrical shape Part, 32C... Thread, 33... Stator, 34... Rotor, 35... Stator core, 36F... Front insulator, 36R... Rear insulator, 37... Coil, 38... Short circuit member, 39... Connector, 39S... Screw, 40... Rotor core , 41... Rotor shaft, 42... Rotor magnet, 43... Rotation sensor board, 43S... Screw, 44... Rotor bearing, 45... Rotor bearing, 46... Circlip, 47... Pinion gear, 48... Spindle bearing, 48A... Groove, 49 ... Ball, 50 ... Leaf spring, 51 ... Leaf spring, 52 ... O-ring, 53 ... Cup washer, 54 ... Switch, 55 ... Rod, 56 ... Seal, 57 ... Lever, 57A ... Rotating part, 57B ... First protrusion Part, 57C...Second protrusion, 58...Torsion spring, 59...Magnet, 60...Mode sensor board, 61...Circlip, 62...Shaft bearing, 63...Oil seal, 64...O ring, 71...Drive gear, 71A ...Ring part, 71B...Gear part, 71C...Cylindrical part, 71D...Gear ball groove, 72...Clutch cam, 72A...Cam ring part, 72B...Ring groove, 72C...Drive cam part, 72D...Cam ball groove, 73...Ball, 74... Intermediate shaft, 74A... Through hole, 74B... Bearing holding part, 74C... Gear fixing part, 74D... Intermediate part, 74E... Pin support part, 74F... Sleeve support part, 74G... Stop surface, 74H... Convex part, 74J ...Small diameter part, 74K...Large diameter part, 74M...Protuberance, 75...Compression spring, 76...Sleeve, 76A...Cylindrical part, 76B...Stopper part, 77...Rear O-ring, 78...Front O-ring, 79...Lock Pin, 80... Sleeve, 80A... Recess, 81... Compression spring, 82... Brake member, 82A... Brake ring portion, 82B... Recess, 82C... Brake cam portion, AX... Rotating shaft, CX... Rotating shaft.

Claims (13)

housing and
motor and
a clutch cam disposed inside the housing and rotated about a rotating shaft by the motor;
The clutch cam includes a driven cam part that is disposed in front of the clutch cam and faces a driving cam part provided on the clutch cam, and a rod part on which a tip tool is attached, and the driving cam part and the driven cam part are connected to each other. a spindle movably supported by the housing in the front-rear direction so as to be in contact with or separate from each other;
a sleeve disposed inside the housing radially outside of the drive cam part and the driven cam part;
screwdriver. The clutch cam has a cam ring portion disposed around the rotating shaft,
The drive cam portion is provided so as to protrude forward from the front surface of the cam ring portion,
The spindle has a flange portion provided at a rear end portion of the rod portion,
The driven cam portion is provided so as to protrude rearward from the rear surface of the flange portion,
The sleeve is supported by each of the cam ring part and the flange part,
The screwdriver according to claim 1. a front O-ring disposed on the outer periphery of the flange portion and in contact with the sleeve;
The screwdriver according to claim 2. a rear O-ring disposed on the outer periphery of the cam ring portion and in contact with the sleeve;
The screwdriver according to claim 3. the drive cam part and the driven cam part are separated from each other when the spindle is in the forward position;
The drive cam portion and the driven cam portion are capable of contacting each other when the spindle is disposed at a retracted position rearward than the forward position;
The rotational force of the clutch cam is transmitted to the spindle via the sleeve when the spindle is placed in the forward position.
The screwdriver according to claim 3 or 4. The spindle moves toward the retracted position while rotating due to the rotational force of the clutch cam transmitted through the sleeve.
The screwdriver according to claim 5. The spindle rotates due to friction between the sleeve and the front O-ring.
The screwdriver according to claim 6. a brake member supported by the housing and preventing rotation of the spindle when the spindle is in the forward position;
The screwdriver according to any one of claims 5 to 7. The spindle has a front cam portion that protrudes forward from the front surface of the flange portion,
The brake member includes a brake ring portion supported by the housing, and a brake cam portion that contacts the front cam portion when the spindle is in the forward position.
The screwdriver according to claim 8. When the spindle moves from the forward position to an intermediate position between the forward position and the retracted position, the rotation is no longer inhibited by the brake member, and the spindle starts rotating.
A screwdriver according to claim 9. a drive gear, at least a portion of which is located behind the clutch cam, and which is rotated by the motor around the rotating shaft;
The clutch cam is supported by the drive gear,
The sleeve includes a cylindrical portion disposed around each of the cam ring portion and the flange portion, and a stopper portion that contacts the front surface of the drive gear.
A screwdriver according to any one of claims 2 to 10. The clutch cam has a cam ball groove provided on the rear surface of the cam ring portion,
The cam ball groove has an arc shape in a plane perpendicular to the rotation axis,
At least a portion of the cam ball groove is inclined in the front-rear direction,
a ball disposed in the cam ball groove;
the clutch cam is coupled to the drive gear via the ball,
The clutch cam moves forward when the driving cam part and the driven cam part come into contact with each other.
The screwdriver according to claim 11. a compression spring disposed radially inside the sleeve and biasing the clutch cam rearward;
When the torque applied to the spindle, which rotates due to the rotational force of the clutch cam transmitted via the drive cam section and the driven cam section, decreases, the compression spring moves the clutch cam rearward, and the drive cam moves backward. the cam portion and the driven cam portion are separated;
A screwdriver according to claim 12.

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