JP6290041B2 - Screw tightening tool - Google Patents

Description

  The present invention relates to a screw tightening tool that rotationally drives a tip tool.

  Japanese Patent Application Laid-Open No. 9-011148 discloses a screw tightening tool that performs screw tightening by driving a bit attached to an output shaft member. In this screw tightening tool, in a state where a screw attached to the tip of a bit is pressed against a work material, a motor rotationally drives an output shaft member to perform a screw tightening operation.

JP-A-9-011148

  In the screw tightening tool as described above, a screw tightening operation is performed by pressing a bit as a tip tool against a workpiece through a screw. When performing the screw tightening operation, the screw is attached to the tip of the tip tool without pressing the tip tool as a preparatory step, so that the tip tool is surely stopped when the tip tool is not pressed. Is preferred. This invention is made | formed in view of the above, and makes it a subject to provide an effective technique in order to restrict | limit rotation of a front-end tool appropriately.

  The above problems are solved by the present invention. According to a preferred embodiment of the screw tightening tool according to the present invention, a screw tightening tool that performs a predetermined work by rotating the tip tool removably attached to the tip region is configured. The screw tightening tool is rotationally driven by a motor in a predetermined forward rotation direction and a reverse rotation direction by the motor, and rotates the tip tool in a first direction corresponding to the forward rotation direction and a second direction corresponding to the reverse rotation direction. A tip tool drive shaft that can be driven, and a rotation restricting mechanism that engages with the tip tool drive shaft to restrict the rotation of the tip tool drive shaft. The tip tool drive shaft is configured to be movable between a first position close to the tip region and a second position separated from the tip region with respect to the axial direction of the tip tool drive shaft. The first position is also referred to as a front position, and the second position is also referred to as a rear position. The rotation restricting mechanism has a movable member that can move between an engageable position that can be engaged with the tip tool drive shaft and an unengageable position that cannot be engaged with the tip tool drive shaft. Typically, the movable member is configured to move in a direction perpendicular to the axial direction of the tip tool drive shaft. Preferably, the movable member is moved in a direction perpendicular to the axial direction of the tip tool drive shaft by moving in the circumferential direction around the axis of the tip tool drive shaft. In this case, it is preferable that the movable member is moved in the circumferential direction based on the rotation of the tip tool drive shaft when the tip tool drive shaft is positioned at the first position. Accordingly, when the movable member is positioned at the non-engageable position with the tip tool drive shaft positioned at the first position, the tip tool drive is performed to move the movable member from the non-engageable position to the engageable position. Although the shaft is slightly rotated in the forward rotation direction, when the movable member is positioned at the non-engageable position, the rotation of the tip tool drive shaft in the forward rotation direction is restricted.

  The rotation restricting mechanism is configured such that when the tip tool drive shaft is located at the first position, the movable member located at the engageable position engages with the tip tool drive shaft to rotate the tip tool drive shaft in the forward rotation direction. The movable member is positioned at the non-engageable position, and the tip tool drive shaft is allowed to rotate in the reverse rotation direction. On the other hand, when the tip tool drive shaft is located at the second position, the rotation restricting mechanism allows the tip tool drive shaft to rotate in the forward rotation direction and the reverse rotation direction.

  The movable member may be arranged at the non-engageable position when the tip tool drive shaft is located at the second position, and the movable member when the tip tool drive shaft is located at the second position. Regardless of the position, the tip tool drive shaft may be provided with a small diameter portion so that the tip tool drive shaft and the movable member do not engage with each other. More specifically, the tip tool drive shaft has a large diameter portion and a small diameter portion formed in a region closer to the tip region than the large diameter portion. The large diameter portion can be engaged with the movable member when the movable member is located at the engageable position, and cannot be engaged with the movable member when the movable member is located at the non-engageable position. On the other hand, the small diameter portion cannot be engaged with the movable member regardless of the position of the movable member. When the tip tool drive shaft is located at the first position, the large diameter portion is disposed at a position corresponding to the movable member, and when the tip tool drive shaft is located at the second position, the small diameter portion corresponds to the movable member. Placed in position.

  According to the present invention, when the tip tool drive shaft is positioned at the front position, the tip tool is appropriately rotated. Therefore, the rotation restricting mechanism appropriately restricts the rotation of the tip tool according to the work mode. Thereby, the workability | operativity at the time of attaching a screw to a front-end tool improves, for example. That is, the first direction is set as a screw tightening direction in which the tip tool performs screw tightening work, and the second direction is set as a screw unscrewing direction in which the tip tool performs screw unscrewing work.

  According to the further form of the screw fastening tool which concerns on this invention, a rotation control mechanism has a movable member holding member holding a movable member. The movable member is switched between the engageable position and the non-engageable position by moving in a holding region formed in the movable member holding member. Typically, the holding region extends in the circumferential direction around the axis of the tip tool drive shaft, and the tip tool drive shaft is in a direction perpendicular to the axial direction of the tip tool drive shaft from the rotation axis of the tip tool drive shaft. Formed as a recess having a first region separated from the rotation axis by a first distance, and a second region connected to the first region and separated from the rotation axis of the tip tool drive shaft by a second distance longer than the first distance. Yes. Therefore, the position of the movable member arranged in the first region is set as an engageable position, and the position of the movable member arranged in the second region is set as an incapable position. As a result, the movable member is disposed at the engageable position and the non-engageable position by moving the movable member within the recess in which the first region and the second region are continuously formed. Preferably, the second region is configured so that the movable member disposed in the second region does not approach the tip tool drive shaft in the radial direction of the tip tool drive shaft when the tip tool drive shaft rotates in the reverse rotation direction. It is formed so as to hold the movable member.

  According to the further form of the screw fastening tool which concerns on this invention, it has a housing which accommodates a front-end tool drive shaft. Further, the rotation restricting mechanism has an elastic member disposed between the movable member holding member and the housing. The elastic member holds the movable member holding member fixed to the housing and suppresses vibration transmission from the movable member holding member to the housing. Since the elastic member is interposed between the movable member holding member and the housing, for example, assembling becomes easier as compared with a configuration in which the movable member holding member is press-fitted into the housing. In addition, transmission of vibration generated in the drive mechanism during operation to the housing by the elastic member is efficiently suppressed.

  According to the further form of the screw fastening tool which concerns on this invention, the movable member is formed as a spherical body. Therefore, the movable member moves smoothly between the engageable position and the disengageable position.

  ADVANTAGE OF THE INVENTION According to this invention, in a screw fastening tool, the technique effective in order to restrict | limit rotation of a front-end tool appropriately is provided.

It is a side view showing the whole screw driver composition concerning a 1st embodiment of the present invention. It is a partial bottom view of a screw driver. It is a whole sectional view of a screwdriver. It is sectional drawing in the IV-IV line of FIG. It is sectional drawing in the VV line of FIG. It is a side view of a drive mechanism. It is a perspective view of a drive mechanism. It is a perspective view of a retainer. It is a perspective view of a lock sleeve. It is sectional drawing in the XX line of FIG. It is sectional drawing in the XI-XI line of FIG. It is sectional drawing in the XII-XII line | wire of FIG. It is a perspective view of a stopper. It is a disassembled perspective view of a stopper. It is sectional drawing in the XV-XV line | wire of FIG. FIG. 5 is a cross-sectional view corresponding to FIG. 4 during a screw tightening operation. FIG. 7 is a side view corresponding to FIG. 6 during a screw tightening operation. It is sectional drawing in the XVIII-XVIII line of FIG. It is sectional drawing in the XIX-XIX line | wire of FIG. It is sectional drawing in the XX-XX line of FIG. FIG. 13 is a cross-sectional view corresponding to FIG. 12 during a screw removing operation. FIG. 12 is a cross-sectional view corresponding to FIG. 11 during a screw removing operation. FIG. 16 is a cross-sectional view corresponding to FIG. 15, showing a state where the rotation of the spindle in the screw tightening direction is restricted by the stopper. It is the elements on larger scale which show an oil seal. It is sectional drawing in the XXV-XXV line | wire of FIG. It is a disassembled perspective view of the stopper in 2nd Embodiment of this invention. It is sectional drawing of the stopper at the time of screw removal operation | work.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, a screw driver 100 that performs a predetermined operation on a workpiece such as a gypsum board is configured as an example of a screw tightening tool. The screw driver 100 is mainly composed of a main body 101 and a handle 107. A tool bit 119 is detachably attached to the tip region of the main body 101. For convenience of explanation, the tool bit 119 side (right side in FIG. 1) is defined as the front side of the screw driver 100 with respect to the major axis direction (left and right direction in FIG. 1) of the tool bit 119, and the handle 107 side (left side in FIG. 1). ) Is defined as the rear side of the screwdriver 100. 1, the upper side of FIG. 1 is defined as the upper side of the screw driver 100, and the lower side of FIG. 1 is defined as the lower side of the screw driver 100.

  As shown in FIGS. 1 to 3, the main body 101 is configured mainly with a main housing 103, a front housing 104, and a locator 105. The main housing 103 mainly accommodates the motor 110. The front housing 104 is attached to the front side of the main housing 103 and accommodates the drive mechanism 120. The front housing 104 is an implementation configuration example corresponding to the “housing” in the present invention.

  As shown in FIG. 3, a partition wall 103 a for partitioning the interior of the front housing 104 and the interior of the main housing 103 is provided at the front end of the main housing 103 so as to extend in the vertical direction. The output shaft 111 of the motor 110 is rotatably supported by a bearing 111 a held by the partition wall 103 a and a bearing 111 b held by the rear portion of the main housing 103. The output shaft 111 is arranged in parallel to the long axis direction of the tool bit 119 (spindle 160). The locator 105 is attached so as to cover the front housing 104 at the front end region of the front housing 104. The tool bit 119 is detachably attached to the drive mechanism 120 so that the tip of the tool bit 119 protrudes forward from the locator 105 in the tip region of the main body 101. The locator 105 is movable relative to the front housing 104 in the long axis direction of the tool bit 119, and is fixed at a predetermined position selected in the long axis direction. Thereby, the protrusion amount from which the tool bit 119 protrudes from the locator 105 is appropriately set. That is, the screw tightening depth is set.

  The handle 107 is connected to the rear of the main body 101 (main housing 103). The handle 107 is provided with a trigger 107a and a changeover switch 107b. When the trigger 107a is operated, a current is supplied from the outside via the power cable 109, and the motor 110 is driven. Further, the rotation direction of the output shaft 111 of the motor 110 is switched by operating the changeover switch 107b. That is, the output shaft 111 is driven by selecting one of the rotation directions of forward rotation and reverse rotation. The motor 110 is an implementation configuration example corresponding to the “motor” in the present invention.

[Drive mechanism]
As shown in FIGS. 3 to 12, the drive mechanism 120 is mainly composed of a drive gear 125, a retainer 130, a roller 140, a lock sleeve 145, a spring receiving member 150, a coil spring 155, a spindle 160 and the like.

[Drive gear]
As shown in FIGS. 4 and 5, the drive gear 125 is disposed coaxially with the spindle 160 that holds the tool bit 119. The drive gear 125 is a substantially cup-shaped member that has a bottom wall 126 and a side wall 127 and is opened forward. A through-hole through which the rear shaft portion 162 of the spindle 160 passes is provided at the center of the bottom wall 126. Inside the side wall 127, an internal space formed in a cylindrical shape is formed. A retainer 130, a roller 140, a lock sleeve 145, a coil spring 155, and the like are accommodated in the internal space of the drive gear 125. Gear teeth 128 that engage with gear teeth 112 formed on the output shaft 111 of the motor 110 are provided on the outer periphery of the side wall 127. The drive gear 125 is supported by a needle bearing 121 provided behind the bottom wall 126 so as to be rotatable with respect to the main body 101 (the partition wall 103a).

[Retainer]
As shown in FIGS. 4 to 8 and FIGS. 9 to 12, the retainer 130 is a substantially cup-shaped member and is disposed coaxially with the drive gear 125. The retainer 130 has a base 131 that faces the bottom wall 126 of the drive gear 125, and a first side wall 132 and a second side wall 133 that face the side wall 127 of the drive gear 125. 6 and 7, the drive gear 125 is not shown.

  As shown in FIGS. 4, 8 and 12, the base 131 is provided with a through hole through which the rear shaft 162 of the spindle 160 passes. As shown in FIG. 12, the through hole of the base 131 is provided with an engagement hole 131 a having a predetermined length in the circumferential direction of the spindle 160. On the other hand, as shown in FIG. 4, a groove portion 162 a extending in the axial direction of the spindle 160 is formed in the rear shaft portion 162 of the spindle 160. As shown in FIG. 12, the cross section of the groove 162 a orthogonal to the axial direction of the spindle 160 is formed in a substantially semicircular shape corresponding to the cylindrical engagement pin 139 that connects the spindle 160 and the retainer 130. . Therefore, since the engagement hole 131a has a predetermined length in the circumferential direction of the spindle 160, the spindle 160 is within the range of the engagement hole 131a with the engagement pin 139 engaged with the spindle 160 and the retainer 130. The retainer 130 is configured to be relatively rotatable.

  As shown in FIGS. 4 to 8 and 11, the first side wall 132 and the second side wall 133 are formed so as to protrude forward from the base 131 in the axial direction (front-rear direction) of the retainer 130. . A pair of first side walls 132 and a pair of second side walls 133 are formed on both sides of the central axis of the retainer 130. In other words, the second side wall 132 is interposed between the first side walls 132 in the circumferential direction of the retainer 130. A side wall 133 is disposed. As shown in FIG. 11, with respect to the circumferential direction of the retainer 130, a roller holding part 134 for holding the roller 140 formed as a predetermined space is provided between the first side wall 132 and the second side wall 133. Yes. Accordingly, the retainer 130 holds the four rollers 140 between the first side wall 132 and the second side wall 133.

  Further, as shown in FIGS. 6 to 8, the front end portion of the second side wall 133 is provided with an inclined portion 133 a composed of an inclined surface inclined with respect to the rotation axis of the spindle 160 (the central axis of the retainer 130). It has been. The inclined portions 133 a formed on the two second side walls 133 are formed symmetrically with respect to the central axis of the retainer 130. In other words, the two inclined portions 133a are configured as lead surfaces formed along the circumferential direction of the retainer 130, and have the same angle with respect to the outline (outer periphery) of the retainer 130 in a cross section orthogonal to the axial direction of the retainer 130. It is formed to be inclined at. That is, the two inclined portions 133a are formed in a double spiral shape.

  As shown in FIGS. 5, 6, and 12, the base 131 is formed with a ball holding portion 131 b in a region corresponding to each of the two second side walls 133. The two ball holding portions 131b are formed point-symmetrically with respect to the central axis of the retainer 130. The ball holding portion 131 b is formed as a groove deeper than the thickness of the second side wall 133 in the radial direction of the retainer 130. As a result, as shown in FIG. 5, the outside and the inside of the retainer 130 communicate with each other through the ball holding portion 131 b in the radial direction of the retainer 130.

  As shown in FIG. 12, the ball holding portion 131b has a groove depth that is the distance from the outer peripheral surface of the retainer 130 to the center side of the retainer 130 in the ball holding portion 131b in the radial direction of the retainer 130. It is formed so as to be asymptotically shallow along the direction. Specifically, the depth of the ball holding portion 131b is set so that the groove of the ball holding portion 131b gradually becomes shallower in the clockwise direction (B direction) indicated by the arrow B in FIG. Balls 153 are arranged on the two ball holding portions 131b, respectively. When the ball 153 is located in a region where the groove depth of the ball holding portion 131b is shallow, the ball 153 includes the bottom wall (center side wall) of the ball holding groove 131b and the inner peripheral surface of the drive gear 125. It arrange | positions so that it may contact | abut. On the other hand, when the ball 153 is located in a region where the groove of the ball holding portion 131b is deep, the ball 153 contacts at least one of the bottom wall of the ball holding groove 131b and the inner peripheral surface of the drive gear 125. do not do.

[Lock sleeve]
As shown in FIGS. 4 to 7, 9, and 10, the lock sleeve 145 is a substantially hexagonal columnar member, and a hollow portion is formed inside. The lock sleeve 145 is disposed in front of the retainer 130 so as to be coaxial with the retainer 130 and the drive gear 125. The front end portion of the lock sleeve 145 is disposed so as to be able to contact the rear end portion of the front shaft portion 161 of the spindle 160. The lock sleeve 145 has four roller engaging portions 146 that can be engaged with the rollers 140 and two retainer engaging portions that can be engaged with the second side wall 133 of the retainer 130 corresponding to the six sides of the hexagon. 147.

  As shown in FIG. 10, the roller engaging portion 146 is configured by four planes parallel to the rotation axis of the spindle 160 (the central axis of the lock sleeve 145). Note that the two opposing surfaces are formed parallel to each other. The roller engaging portion 146 is configured to be engageable (contactable) with the roller 140 on the center side of the first side wall 132 and the second side wall 133 in the radial direction of the retainer 130.

  Also, as shown in FIG. 10, the retainer engaging portion 147 is formed in a region that is substantially the same distance as the radius of the retainer 130 from the central axis of the lock sleeve 145 in the radial direction of the retainer 130. As shown in FIGS. 6, 7, and 9, with respect to the front-rear direction, the rear end portion of the retainer engaging portion 147 has an inclined surface that is inclined with respect to the rotation axis of the spindle 160 (the central axis of the lock sleeve 145). A configured inclined portion 147a is provided. The inclined portion 147a is formed corresponding to the inclined portions 133a of the two second side walls 133, respectively. That is, the inclined portion 147a can be engaged (contactable) with the inclined portion 133a. Therefore, similarly to the inclined portion 133a, the two inclined portions 147a are formed point-symmetrically with respect to the central axis of the lock sleeve 145. In other words, the two inclined portions 147a are configured as lead surfaces formed along the circumferential direction around the axial direction of the lock sleeve 145, and the outer shape of the retainer engaging portion 147 in a cross section orthogonal to the axial direction of the lock sleeve 145. It is formed so as to be inclined at the same angle with respect to the line (outer periphery). That is, the two inclined portions 147a are formed in a double spiral shape.

[Spring receiving member]
As shown in FIGS. 4, 5, and 11, the spring receiving member 150 is a member having a substantially hexagonal cross section and is accommodated inside the retainer 130. The spring receiving member 150 is disposed between the base 131 of the retainer 130 and the lock sleeve 145 in the front-rear direction. The spring receiving member 150 has a through hole through which the spindle 160 passes. Then, the engaging pin 139 disposed in the groove 162a of the rear shaft portion 162 engages with a substantially semicircular engaging hole 150a formed in the spring receiving member 150, whereby the spring receiving member 150 is , Coupled to the spindle 160 so as to rotate integrally with the spindle 160. Four roller engaging portions 151 corresponding to four of the six hexagonal sides are formed on the outer periphery of the spring receiving member 150. The roller engaging portion 151 is formed as a plane parallel to the rotation axis of the spindle 160.

  Further, as shown in FIG. 5, a ball contact portion 152 that contacts the ball 153 is formed on the rear surface of the spring receiving member 150. The ball abutting portion 152 abuts the region of the ball 153 closer to the rotation axis of the retainer 130 (the rotation axis of the spindle 160) than the center of the ball 153 with respect to the radial direction of the retainer 130. Acts to push outward in the direction. Note that the ball contact portion 152 may be formed as an inclined surface that is inclined with respect to the axial direction of the spindle 160. The ball 153 pushed outward in the radial direction of the spindle 160 abuts on the inner peripheral surface of the drive gear 125. Accordingly, the ball 153 moves in the ball holding portion 131b by the rotation of the drive gear 125.

[spindle]
As shown in FIGS. 4 to 7 and FIGS. 10 to 12, the spindle 160 is a long, substantially columnar member made of metal and extends in the major axis direction of the spindle 160 (the major axis direction of the tool bit 119). It is provided to be movable. The spindle 160 is mainly composed of a front shaft portion 161 and a rear shaft portion 162 integrally connected to the front shaft portion 161. A tool bit 119 is detachably attached to the front shaft portion 161. The tool bit 119 is engaged with a ball urged by a leaf spring held on the front shaft portion 161, whereby the tool bit 119 is held on the front shaft portion 161. The front shaft portion 161 is rotatably supported by a front bearing 122 held by the front housing 104. As shown in FIGS. 4 and 5, an oil seal 181 is provided between the front housing 104 and the front shaft portion 161 in front of the front bearing 122 that supports the front shaft portion 161. .

  The rear shaft portion 162 is connected to the front shaft portion 161 coaxially with the front shaft portion 161. The rear end portion of the rear shaft portion 162 is slidable in the front-rear direction with respect to a cylindrical rear end bearing 165 provided on the partition wall 103a of the main housing 103, and is supported rotatably. . The rear end bearing 165 is configured as an oilless bearing. As a result, the spindle 160 is supported by the front bearing 122 and the rear end bearing 165. The rear shaft portion 162 passes through the drive gear 125, the retainer 130 and the lock sleeve 145, and the rear end portion of the rear shaft portion 162 protrudes rearward from the drive gear 125. The rear shaft portion 162 is formed with a groove portion 162a extending in the rotation axis direction of the spindle 160. The rear end portion of the groove portion 162a abuts on the engagement pin 139, so that the axial direction of the spindle 160 is related. Forward movement is restricted. On the other hand, the engagement pin 139 is in contact with the rear end portion of the coil spring 155 and is restricted from moving forward in the axial direction of the spindle 160.

  A hollow portion 163 that opens to the rear end surface of the rear shaft portion 162 and extends in the major axis direction of the spindle 160 is formed in the rear shaft portion 162. That is, the hollow portion 163 communicates with the rear end bearing 165. The rear shaft portion 162 is formed with a communication hole 164 that penetrates the rear shaft portion 162 in the radial direction and communicates the hollow portion 163 with the interior of the front housing 104. Therefore, the inside of the front housing 104 and the inside of the rear end bearing 165 communicate with each other through the hollow portion 163. Accordingly, as shown in FIG. 16, when the spindle 160 moves rearward, the compression of the air inside the rear end bearing 165 is restricted. In other words, since the communication hole 164 is provided, the air inside the rear end bearing 165 is not compressed, and the backward movement of the spindle 160 is not hindered.

  Further, as shown in FIGS. 4 and 5, a large diameter portion 166 that can be engaged with the stopper 170 and a small diameter portion 167 that cannot be engaged with the stopper 170 are formed at the rear end portion of the front shaft portion 161. Yes. As shown in FIG. 15, the large-diameter portion 166 has an arc-shaped portion 166a having a diameter D1 and a two-surface width portion 166b having a width W. On the other hand, as shown in FIG. 20, the small diameter portion 167 is formed in a circular shape having a diameter D2. The length of the diameter D2 is the same length as the width W of the two-surface width portion 166b. The large diameter portion 166 and the small diameter portion 167 are implementation configuration examples corresponding to the “large diameter portion” and the “small diameter portion” in the present invention, respectively.

[Coil spring]
As shown in FIGS. 4 and 5, the coil spring 155 is disposed so that the spindle 160 penetrates coaxially with the spindle 160. The front region of the coil spring 155 is accommodated in the hollow portion of the lock sleeve 145, and the front end portion of the coil spring 155 is in contact with the lock sleeve 145. The rear end of the coil spring 155 is in contact with the front surface of the spring receiving member 150. As a result, the coil spring 155 biases the lock sleeve 145 and the spindle 160 forward. The lock sleeve 145 biased forward biases the spindle 160 and abuts against the stopper 170 to restrict forward movement. The coil spring 155 urges the spring receiving member 150, the ball 153, the retainer 130, and the drive gear 125 toward the rear. As shown in FIG. 5, the ball 153 is urged by the coil spring 155 and is pushed out toward the outside in the radial direction of the retainer 130 via the ball contact portion 152 of the spring receiving member 150. Abuts on the inner surface.

[Stopper]
As shown in FIGS. 4 and 5, the stopper 170 constitutes a rotation prevention mechanism that restricts the rotation of the spindle 160 in a predetermined direction when the spindle 160 is located at the front position. The stopper 170 is formed in a ring shape, and is disposed on the outer peripheral portion of the spindle 160 so that the spindle 160 passes therethrough. The stopper 170 is fixed to the front housing 104 by an O-ring 180 disposed between the front housing 104 and the front housing 104. As shown in FIGS. 13 to 15, the stopper 170 is mainly composed of a ball holding ring 171, a push ring 173, a ball 175 and a leaf spring 177.

  As shown in FIGS. 13 and 14, the ball holding ring 171 is a metal ring-like member, and holds a ball 175 that can be engaged with the spindle 160. As shown in FIGS. 14 and 15, the ball holding ring 171 is formed with two holding grooves 172 along the circumferential direction. A ball 175 is held in the holding groove 172 so as to be movable in the circumferential direction of the ball holding ring 171. With respect to the radial direction of the ball holding ring 171, the holding groove 172 has an asymptotic depth along the circumferential direction of the ball holding ring 171 that is the distance from the inner peripheral surface of the ball holding ring 171 to the bottom surface of the holding groove 172. It is formed to be deep. Specifically, the depth (the length in the radial direction) of the holding groove 172 is set so that the holding groove 172 gradually becomes deeper in the B direction (screw removing direction) in FIG. A pocket-shaped region 172a is formed in the front portion of the holding groove 172 in the B direction. The wall with which the ball 175 strikes when moving in the B direction in the holding groove 172 extends in a predetermined radial direction of the ball holding ring 171, thereby forming a pocket-shaped region 172 a in the holding groove 172. Therefore, when the ball 175 is positioned at the position shown in FIG. 15 (pocket-shaped region 172a), the ball 175 is held in the pocket-shaped region 172a, so that the center of the ball holding ring 171 in the radial direction (of the spindle 160). The movement of the ball 175 toward the rotation axis) is restricted. This ball holding ring 171 is an implementation configuration example corresponding to the “movable member holding member” in the present invention. In addition, the holding groove 172 is an implementation configuration example corresponding to the “holding region” and the “concave portion” in the present invention.

  A substantially C-shaped leaf spring 177 is disposed on the inner periphery of the ball holding ring 171. As shown in FIG. 14, the leaf spring 177 is formed with two through holes 177a corresponding to the two holding grooves 172, respectively. A part of the ball 175 protrudes toward the center of the ball holding ring 171 through the through hole 177a. That is, the ball 175 has a diameter larger than the depth of the holding groove 172. Therefore, the leaf spring 177 functions as a drop-off preventing member that prevents the ball 175 from dropping from the holding groove 172 to the center of the ball holding ring 171 in the radial direction of the ball holding ring 171. With the above configuration, the protruding amount of the ball 175 protruding from the through hole 177a of the leaf spring 177 varies depending on the position of the ball 175 in the holding groove 172.

  As shown in FIGS. 13 and 14, the leaf spring 177 has an engagement hole 177 b that engages with the ball 176 held by the ball holding ring 171. With the leaf spring 177 disposed on the inner peripheral portion of the ball holding ring 171, the ball 176 is fitted into the holding ring 171 using the elastic deformation of the leaf spring 177 and then the ball 175 is fitted into the holding groove 172. The ball holding ring 171, the ball 175, and the leaf spring 177 are integrated. Note that the holding groove 172 is open toward the rear, and the ball 175 is moved from the rear of the ball holding ring 171 and disposed in the holding groove 172. On the other hand, the ball 176 is moved from the front of the ball holding ring 171 and engages with the engagement hole 177 b of the leaf spring 177. A holding hole for holding the ball 176 is formed in the ball holding ring 171 so that the ball 176 engaged with the leaf spring 177 cannot move rearward of the ball holding ring 171. As a result, the ball 175 that cannot move forward, the ball 176 that cannot move backward, and the leaf spring 177 are associated with each other while being engaged with the ball holding ring 171, and each component of the stopper 170 is assembled. The As a result, the assembly of the stopper 170 to the front housing 104 is simplified.

  As shown in FIGS. 13 and 14, the push ring 173 is a ring-shaped member having a smaller diameter than the ball holding ring 171 and is accommodated in the ball holding ring 171 coaxially with the ball holding ring 171. The front end surface of the push ring 173 is in contact with the ball 175 held by the ball holding ring 171. The push ring 173 can rotate relative to the ball holding ring 171. The rear end surface of the push ring 173 can contact and separate from the shoulder portion of the lock sleeve 145 that is offset rearward from the front end surface of the lock sleeve 145. That is, as shown in FIG. 5, when the lock sleeve 145 is biased by the coil spring 155 and is positioned at the front position, the lock sleeve 145 and the push ring 173 come into contact with each other. On the other hand, as shown in FIG. 16, when the lock sleeve 145 is located at the rear position, the lock sleeve 145 and the push ring 173 are separated from each other.

  When the lock sleeve 145 is rotated with the lock sleeve 145 positioned at the front position and in contact with the push ring 173, the push ring 173 contacts the ball 175 and the ball 175 is held. Move in the groove 172. As a result, the amount of protrusion of the ball 175 from the holding groove 172 varies in the radial direction of the ball holding ring 171. That is, as shown in FIG. 20, when the ball 175 moves in the A direction (screw tightening direction), the amount of protrusion of the ball 175 from the leaf spring 177 increases, and as shown in FIG. 15, the B direction (unscrewing). When the ball 175 moves in the direction), the amount of protrusion of the ball 175 from the lease spring 177 decreases. That is, the ball 175 is moved in the circumferential direction of the spindle 160, so that the ball 175 moves away from the center axis of the spindle 160 shown in FIG. 15 (also referred to as a separated position) and close to the center axis of the spindle 160 shown in FIG. Move between positions (also called proximity positions). This ball 175 is an implementation configuration example corresponding to the “movable member” in the present invention.

  When the ball 175 is positioned at the separated position, the ball 175 does not engage with the large diameter portion 166 and the small diameter portion 167 of the spindle 160. Accordingly, since the ball 175 cannot be engaged with the spindle 160 at the separated position of the ball 175, the separated position is also referred to as an unengageable position. On the other hand, when the ball 175 is located at the close position, the ball 175 can be engaged with the large-diameter portion 166 of the spindle 160. That is, when the ball 175 is located at the close position and the spindle 160 is located at the front position where the large-diameter portion 166 of the spindle 160 faces the ball 175, the ball 175 and the spindle 160 are engaged. On the other hand, when the spindle 160 is positioned at a rear position where the small diameter portion 167 of the spindle 160 and the ball 175 face each other, the ball 175 and the spindle 160 are not engaged. Therefore, since the ball 175 can be engaged with the spindle 160 at the proximity position of the ball 175, the proximity position is also referred to as an engageable position. The movement of the ball 175 in the screw tightening direction switches the ball 175 from the non-engageable position to the engageable position, and the movement of the ball 175 in the unscrewing direction causes the ball 175 to move from the engageable position to the non-engageable position. Can be switched to.

[Operation of screwdriver]
In the screw driver 100 configured as described above, when the trigger 107a is operated, the motor 110 is driven. The drive gear 125 is rotationally driven by the rotation of the output shaft 111 of the motor 110. Then, the rotation of the drive gear 125 is transmitted to the spindle 160, whereby the tool bit 119 held on the spindle 160 is rotated, and a predetermined work (screw tightening work or screw removing work) is performed. This spindle 160 is an implementation configuration example corresponding to the “tip tool drive shaft” in the present invention.

[Screw tightening]
When performing the screw tightening operation, the spindle 160 moves from the front position shown in FIG. 4 to the rear position shown in FIG. 16 by pressing the screw (not shown) at the tip of the tool bit 119 against the workpiece. Is done. The front position and the rear position are implementation configuration examples corresponding to the “first position” and the “second position” in the present invention, respectively. By the movement of the spindle 160, the lock sleeve 145 is rotated with respect to the retainer 130, and the roller 140 is sandwiched between the drive gear 125 and the lock sleeve 145. As a result, the wedge effect of the roller 140 causes the drive gear 125 and the lock sleeve 145 to rotate together, the rotation of the output shaft 111 of the motor 110 is transmitted to the spindle 160 via the drive mechanism 120, and the spindle 160 is rotationally driven. . Thereby, the screw tightening operation is performed by the tool bit 119.

  Specifically, as shown in FIG. 4, when the output shaft 111 of the motor 110 rotates in a predetermined direction (hereinafter referred to as a positive direction) when the spindle 160 is located at the front position, the direction A in FIGS. The driving gear 125 is driven to rotate. At this time, since the roller 140 is not sandwiched between the lock sleeve 145 and the drive gear 125, the rotation of the drive gear 125 is not transmitted to the lock sleeve 145. As shown in FIG. 12, when the driving gear 125 rotates in the A direction, the ball 153 contacts the inner peripheral surface of the driving gear 125 and moves in the A direction in the ball holding portion 131b. Is sufficiently deep (the length in the radial direction), the ball 153 is not sandwiched between the ball holding portion 131b and the drive gear 125. In other words, the ball 153 is held in a loose shape in the ball holding portion 131 b, and the rotation of the drive gear 125 is not transmitted to the retainer 130. This state is also referred to as an idling state.

  When the screw held at the tip of the tool bit 119 is pressed against the workpiece from the idling state, the spindle 160 resists the biasing force of the coil spring 155 and the spindle 160 moves from the front position shown in FIG. 4 to the rear position shown in FIG. Moved to. Accordingly, the lock sleeve 145 is pushed by the rear end portion of the front shaft portion 161 of the spindle 160 and moves rearward, and the retainer engaging portion 147 of the lock sleeve 145 and the second side wall 133 of the retainer 130 come into contact with each other. That is, as shown in FIG. 17, the inclined portion 147 a of the retainer engaging portion 147 and the inclined portion 133 a of the second side wall 133 come into contact with each other. When the inclined portion 147a moves along the inclined portion 133a, the lock sleeve 145 moves rearward and rotates around the axis of the retainer 130. That is, as shown in FIG. 18, the lock sleeve 145 rotates relative to the retainer 130 by a predetermined angle around the rotation axis of the spindle 160 in the B direction. As a result, the distance between the roller engaging portion 146 of the lock sleeve 145 and the inner peripheral surface of the drive gear 125 is shortened, and the roller 140 is sandwiched between the roller engaging portion 146 and the inner peripheral surface of the drive gear 125. Thereby, the roller 140 acts as a wedge, and the drive gear 125 and the lock sleeve 145 are integrated via the roller 140. The position of the roller 140 held between the lock sleeve 145 and the drive gear 125 (the position in FIG. 18) is also referred to as a rotation transmission position. Therefore, the neutral position of the roller 140 that is not sandwiched between the lock sleeve 145 and the drive gear 125 (the position in FIG. 10) is also referred to as a rotation transmission impossible position.

  At this time, as shown in FIG. 17, the inclined portion 147 a of the lock sleeve 145 is in contact with the inclined portion 133 a of the retainer 130. Therefore, as shown in FIG. 18, when the drive gear 125 is rotationally driven in the direction A by the output shaft 111 of the motor 110, the lock sleeve 145 integrated with the drive gear 125 is rotated. The inclined portion 147a presses the retainer 130 in the A direction, and rotates the retainer 130 in the A direction.

  As illustrated in FIG. 19, the retainer 130 rotated in the A direction rotates the spindle 160 in the A direction (screw tightening direction) via the engagement pin 139 that engages with the engagement hole 131 a of the retainer 130. As a result, the screw tightening operation is performed by the tool bit 119 held on the spindle 160. As shown in FIG. 16, when the spindle 160 is located at the rear position, the small diameter portion 167 of the spindle 160 faces the ball 175 of the stopper 170. Since the ball 175 does not engage with the small diameter portion 167, the rotation of the spindle 160 in the screwing direction is not hindered.

  When the screw is screwed into the workpiece, the entire screw driver 100 moves forward with the movement of the screw, and the front surface of the locator 105 contacts the workpiece. After the locator 105 comes into contact with the workpiece, when a screw is further screwed into the workpiece, the spindle 160 holding the tool bit 119 moves toward the front of the screw driver 100 with respect to the locator 105 (front housing 104). Moving. That is, the spindle 160 is allowed to move from the rear position shown in FIG. 16 to the front position shown in FIG. In other words, since the spindle 160 is pressed before the locator 105 contacts the workpiece, the relative movement between the spindle 160 and the locator 105 is restricted with respect to the rotation axis direction of the spindle 160.

  The urging force of the coil spring 155 acts forward on the spindle 160 via the lock sleeve 145. Further, the lock sleeve 145 presses the retainer 130 and moves (rotates) the retainer 130 around the rotation axis of the spindle 160, so that the lock sleeve 145 receives a reaction force from the retainer 130. Specifically, since the lock sleeve 145 and the retainer 130 are in contact with the inclined portion 147a and the inclined portion 133a that are inclined with respect to the rotation axis of the spindle 160, the lock sleeve 145 is a reaction force in the rotation axis direction of the spindle 160. And receives a reaction force around the rotation axis.

  Therefore, during the screw tightening operation, if the spindle 160 is allowed to move from the rear position to the front position after the locator 105 contacts the workpiece, the resultant force of the biasing force of the coil spring 155 and the reaction force from the retainer 130 is obtained. The lock sleeve 145 is moved forward from the position shown in FIG. 16 by (force in the rotation axis direction of the spindle 160). That is, the resultant force exceeds the frictional force between the roller 140 and the lock sleeve 145. In other words, the frictional force between the roller 140 and the lock sleeve 145 is not increased only by the urging force of the coil spring 155, and the resultant force of the urging force of the coil spring 155 and the reaction force from the retainer 130 is between the roller 140 and the lock sleeve 145. Exceeds frictional force. Therefore, the lock sleeve 145 is not moved forward only by the urging force of the coil spring 155, and the lock sleeve 145 is moved forward by the resultant force of the urging force of the coil spring 155 and the reaction force from the retainer 130. As a result, the lock sleeve 145 and the retainer 130 are separated from each other in the rotation axis direction of the spindle 160, and a gap is formed between the retainer 130 and the lock sleeve 145. As a result, the lock sleeve 145 shown in FIG. 18 is rotated relative to the drive gear 125 in the A direction, and the nipping of the roller 140 between the drive gear 125 and the lock sleeve 145 is released. That is, the wedge action of the roller 140 is released. Accordingly, the rotation transmission from the drive gear 125 to the spindle 160 is interrupted, and the screw tightening operation is completed.

[Unscrewing work]
During the unscrewing operation for removing the screw screwed into the workpiece, the screw driver 100 (tool bit 119) rotates the screw in the reverse direction, thereby removing the screw from the workpiece. In this unscrewing operation, it is not reasonable to press the tool bit 119 against the screw. Therefore, in the screw driver 100, the tool bit 119 is driven by the motor 110 without pressing the tool bit 119 in the screw removing operation. That is, the spindle 160 (tool bit 119) is rotated in the reverse direction when the spindle 160 is in the forward position.

  Specifically, as shown in FIG. 1, at the time of unscrewing work, the changeover switch 107b is switched so that the output shaft 111 of the motor 110 rotates in a direction opposite to the forward direction (hereinafter referred to as the reverse direction). An LED 107c is provided in the vicinity of the changeover switch 107b, and the LED 107c emits light when the trigger 107a is operated in a state where the rotation direction of the output shaft 111 is switched to the reverse direction. That is, the operator is informed that the unscrewing operation is performed by the LED 107c. When the output shaft 111 of the motor 110 rotates in the reverse direction, the drive gear 125 rotates in the B direction in FIGS. At this time, since the roller 140 is not sandwiched between the lock sleeve 145 and the drive gear 125, the rotation of the drive gear 125 is not transmitted to the lock sleeve 145.

  On the other hand, the rotation of the drive gear 125 in the B direction causes the ball 153 shown in FIG. 12 to contact the inner peripheral surface of the drive gear 125 and move in the B direction in the ball holding portion 131b, and is arranged at the position shown in FIG. The Since the depth (the length in the radial direction) of the ball holding portion 131b becomes shallower (shorter) in the B direction, the ball 153 moves in the B direction in the ball holding portion 131b, so that the ball holding portion 131b It is clamped by the drive gear 125. Thereby, the ball 153 acts as a wedge, and the drive gear 125 and the retainer 130 are integrated via the ball 153.

  As shown in FIG. 21, the engagement hole 131a formed in the retainer 130 has a predetermined length in the circumferential direction of the spindle 160, and relative rotation between the spindle 160 and the retainer 130 is allowed. On the other hand, as shown in FIG. 22, relative rotation of the spring receiving member 150 with respect to the spindle 160 is restricted via the engagement pin 139. Therefore, when the retainer 130 is rotated in the B direction integrally with the drive gear 125, the retainer 130 rotates in the B direction with respect to the spindle 160 and the spring receiving member 150, and the roller 140 held by the retainer 130 is moved in the B direction. Moved to. As a result, the roller 140 is sandwiched between the spring receiving member 150 and the drive gear 125. Accordingly, the roller 140 acts as a wedge, and the drive gear 125, the spring receiving member 150, and the spindle 160 are integrated via the roller 140. Therefore, when the drive gear 125 is rotated in the B direction, the spindle 160 is rotated in the B direction (unscrewing direction). As a result, the unscrewing operation is performed by the tool bit 119 held on the spindle 160.

  In the screw driver 100 described above, the screw tightening operation is performed when the spindle 160 is located at the rear position. Since the screw tightening operation is performed by attaching screws one by one to the tip of the tool bit 119, it is preferable that the spindle 160 is surely stopped when the spindle 160 is located at a front position where it is not rotationally driven. . That is, in the idling state, it is preferable that the spindle 160 is stopped about the rotation axis of the spindle 160. Therefore, in the present embodiment, the stopper 170 is provided to prevent the spindle 160 from unintentionally rotating in the screw tightening direction when the spindle 160 is located at the front position. Note that the stopper 170 is prevented from rotating by the ball holding ring 171 of the stopper 170 being fixed to the front housing 104 by the O-ring 180.

  Specifically, as shown in FIG. 4, when the spindle 160 is located at the front position, the large-diameter portion 166 of the spindle 160 faces the ball 175 of the stopper 170. At this time, even if the drive gear 125 is rotationally driven in the A direction, the lock sleeve 145 and the spindle 160 are not normally rotated. However, if the lock sleeve 145 is rotated for some reason, the coil spring 155 is biased. Since the lock sleeve 145 is in contact with the push ring 173, the ball 175 is moved through the push ring 173 in the holding groove 172 by the rotation of the drive gear 125 in the A direction (screw tightening direction) as shown in FIG. Moved in the direction. The depth (the length in the radial direction) of the holding groove 172 is configured to become shallower (shorter) in the A direction. When the ball 175 is disposed at the position shown in FIG. The protruding amount of the protruding ball 175 is maximized. As a result, the large-diameter portion 166 of the spindle 160 contacts the ball 175, and the rotation of the spindle 160 in the A direction is restricted. In particular, as shown in FIG. 23, the ball 175 engages with the two-surface width portion 166b of the large diameter portion 166 to restrict the rotation of the spindle 160 in the A direction.

  On the other hand, the screw removing operation is performed without pressing the tool bit 119 held by the spindle 160 against the workpiece. That is, the unscrewing operation is performed with the spindle 160 positioned at the front position. As shown in FIG. 4, when the spindle 160 is located at the front position, the large-diameter portion 166 of the spindle 160 faces the ball 175 of the stopper 170. At this time, when the drive gear 125 is rotationally driven in the B direction, the lock sleeve 145 urged by the coil spring 155 is in contact with the push ring 173, so that the drive gear 125 rotates in the B direction (unscrewing direction). Thus, the ball 175 is moved in the B direction through the push ring 173 in the holding groove 172 as shown in FIG. The depth (the length in the radial direction) of the holding groove 172 is configured to be deeper (longer) in the B direction. When the ball 175 is disposed at the position shown in FIG. The diameter portion 166 does not contact the ball 175. The stopper 170 allows the spindle 160 to rotate in the unscrewing direction when the spindle 160 is positioned at the front position. Therefore, the unscrewing operation is performed without the ball 175 preventing the rotation of the spindle 160 in the B direction (unscrewing direction).

  Further, in the screw driver 100 described above, as shown in FIG. 4, a lubricant (not shown) such as grease is disposed in the front housing 104 in order to drive the drive mechanism 120 smoothly. Further, in order to prevent the lubricant from flowing out from the front side of the front housing 104, an oil seal 181 is interposed between the outer peripheral portion of the front shaft portion 161 of the spindle 160 and the front housing 104 on the front side of the front housing 104. Are arranged to be. That is, the front housing 104 is formed in a sealed shape.

  As shown in FIG. 24, the oil seal 181 is formed in a ring shape, and has a base portion 181 a attached to the front housing 104 and a lip portion 181 b that contacts the spindle 160. In particular, the base portion 181a that contacts the inner peripheral surface of the front housing 104 is formed of an elastomer. A large diameter portion 104 c having a diameter slightly larger than the outer diameter of the oil seal 181 is formed at the front end portion of the front housing 104. Further, the outer diameter of the oil seal 181 is slightly larger than the inner diameter of the front housing 104. Further, an upper recess 104 a and a lower recess 104 b are formed on the inner peripheral surface of the front housing 104. That is, the plurality of recesses 104a and 104b are formed on the same circumference. In addition, the recessed part may be comprised as a single recessed part formed continuously in the circumferential direction. Further, a convex portion may be provided instead of the concave portion.

  The above oil seal 181 is engaged with the front housing 104 by elastic deformation of the outer peripheral portion of the oil seal 181 by being moved from the front of the front housing 104. At this time, the oil seal 181 is moved along the large diameter portion 104 c of the front housing 104. That is, the large diameter portion 104c functions as a guide when the oil seal 181 is assembled. Further, due to the elastic deformation of the base portion 181 a of the oil seal 181, the recesses 104 a and 104 b and the base portion 181 a of the oil seal 181 are engaged, and the oil seal 181 is firmly fixed so as not to drop off from the front housing 104. That is, the recesses 104 a and 104 b function as a retaining stopper for the oil seal 181. The oil seal 181 is press-fitted into the front housing 104 by elastic deformation, whereby the circumferential rotation of the oil seal 181 is restricted. However, the oil seal 181 is formed in the front housing 104 with respect to the circumferential direction of the oil seal 181. The rotation of the oil seal 181 in the circumferential direction is more effectively suppressed by the plurality of recesses 104a and 104b. Then, the drive mechanism 120 is assembled to the front housing 104 to which the oil seal 181 is assembled. That is, the drive mechanism 120 is disposed in the front housing 104 so that the spindle 160 penetrates the oil seal 181, so that the oil seal 181 is disposed so as to seal the gap between the spindle 160 and the front housing 104. . Note that the lip portion 181 b provided on the inner peripheral portion of the oil seal 181 always abuts on the spindle 160. This prevents the lubricant from flowing out from the front side of the front housing 104.

  On the other hand, on the rear side of the front housing 104, as shown in FIG. 25, the bearing 111a prevents the lubricant from flowing out between the output shaft 111 of the motor 110 and the partition wall 103a. Further, the partition wall 103 a is provided with a ventilation passage 190 that communicates the inside and the outside of the front housing 104. When the screw driver 100 is driven, heat is generated by driving the drive mechanism 120 in the front housing 104, and the pressure of air in the front housing 104 increases. In particular, in the small screw driver 100, since the volume of the front housing 104 is small, the pressure fluctuation of the air in the front housing 104 is large. Therefore, the partition wall 103a is formed with a ventilation passage 190 for suppressing the pressure increase of the air in the front housing 104 by releasing the pressure of the front housing 104 to the outside. That is, the front housing 104 and the main housing 103 communicate with each other through the ventilation passage 190. The ventilation passage 190 is provided behind the drive gear 125 and above the output shaft 111 (not shown in FIG. 25) of the motor 110. As shown in FIGS. 1 and 3, the main housing 103 is provided with an external communication portion 106 configured by a communication hole that communicates the inside of the main housing 103 and the outside of the screw driver 100.

  As shown in FIG. 25, the ventilation passage 190 protrudes forward from the partition wall 103a extending in the vertical direction in order to allow the air inside and outside the front housing 104 to flow and to suppress the outflow of the lubricant. It is comprised by the hollow part of the cylindrical (chimney-like) channel | path formation part 191. FIG. That is, the vent 191a at the front end portion (tip portion) of the passage forming portion 191 is provided at a predetermined distance forward from the front surface 103f (surface on the front housing 104 side) of the partition wall 103a. Thereby, it is suppressed that a lubricant moves to the vent 191a along the partition wall 103a. The vent 191 a is disposed in the vicinity of the drive gear 125. Further, the vent 191 a is provided on the rotational axis side of the drive gear 125 with respect to the radial direction of the drive gear 125 with respect to the outer peripheral portion of the drive gear 125. Centrifugal force is generated by the rotation of the drive gear 125, and the lubricant adhering to the drive gear 125 is moved outward in the radial direction of the drive gear 125. Therefore, the lubricant can be prevented from entering the vent passage 190 from the vent 191a. The ventilation passage 190 prevents the lubricant from flowing out from the front housing 104, and suppresses an increase in air pressure in the front housing 104.

  Further, an oil filter 195 is disposed on the partition wall 103a in preparation for the case where the lubricant flows out from the ventilation passage 190 having the above configuration. The oil filter 195 is made of a material that absorbs liquid, such as felt or sponge. The oil filter 195 is disposed behind the partition wall 103a and behind the ventilation passage 190. That is, the oil filter 195 is held by the partition wall 103a. Therefore, the air in the front housing 104 passes through the ventilation passage 190 and the oil filter 195 and reaches the main housing 103.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. The second embodiment differs from the first embodiment in the shape of the holding groove formed in the ball holding ring of the stopper 170. Therefore, components other than the holding groove are denoted by the same reference numerals as those in the first embodiment, and description thereof is omitted.

  As shown in FIG. 15, in the first embodiment, the pocket-shaped region 172a is formed in the holding groove 172. However, in the second embodiment, instead of the pocket-shaped region 172a, as shown in FIG. A radial movement allowable region 272 a is formed in the holding groove 272. The wall with which the ball 175 abuts when moving in the B direction in the holding groove 272 extends along a predetermined tangent line of the inner peripheral portion of the ball holding ring 271, thereby allowing radial movement to the holding groove 272. Region 272a is formed. Therefore, when the ball 175 is positioned at the position shown in FIG. 27 (radial movement allowable region 272a), the ball 175 is allowed to move toward the radial center of the ball holding ring 271 (the rotation axis of the spindle 160). Is done.

  During the unscrewing operation, the rotation of the push ring 173 in the B direction causes the ball 175 to contact the push ring 173 and move in the holding groove 272 in the B direction, and is disposed in the radial movement allowable region 272a. The ball 175 disposed in the radial movement allowable region 272a is further moved toward the radial center (radial inner side) of the ball holding ring 271 by the rotation of the push ring 173 in the B direction. As a result, the ball 175 collides with the large-diameter portion 166 of the spindle 160 rotating in the unscrewing direction (B direction), and the ball 175 is moved radially outward in the radial movement allowable region 272a. Thereafter, the ball 175 is moved again toward the radial center (radially inward) of the ball holding ring 271 by the rotation of the push ring 173 in the B direction. That is, during the unscrewing operation, the ball 175 periodically moves between the radially outer side and the radially inner side in the radial movement allowable region 272a.

  As a result, the ball 175 periodically collides with the large-diameter portion 166 of the spindle 160, and a collision sound is generated. This collision sound constitutes a rotation direction notifying device for notifying the operator that the spindle 160 is being rotated in the unscrewing direction. That is, when the spindle 160 is located at the front position, the stopper 170 restricts rotation of the spindle 160 in the screw tightening direction, allows rotation in the screw unscrewing direction, and the spindle 160 is rotated in the screw unscrewing direction. It also has a function to notify this. Therefore, prior to the unscrewing operation, the operator can easily confirm the rotation direction (unscrewing direction) of the spindle 160. Therefore, in the second embodiment, the LED 107c may not be provided.

  According to the first and second embodiments described above, when the screw tightening operation is performed, the spindle 160 is pressed and moved to the rear position, whereby the inclined portion 147a of the lock sleeve 145 and the inclined portion 133a of the retainer 130 are moved. The roller 140 is moved in the circumferential direction of the retainer 130 with respect to the lock sleeve 145 by the engagement. That is, with respect to the circumferential direction of the retainer 130, the roller 140 is moved from the rotation transmission impossible position to the rotation transmission position. Therefore, by converting the movement of the spindle 160 in the axial direction of the spindle 160 into the movement of the roller 140 in the circumferential direction of the retainer 130 (spindle 160), the position of the roller 140 can be rationally switched based on the screw tightening operation. .

  Further, according to the first and second embodiments, by using the roller 140, the rotation of the output shaft 111 of the motor 110 is caused to rotate by the wedge effect of the roller 140 sandwiched between the drive gear 125 and the lock sleeve 145. 160 is reliably transmitted.

  Further, according to the first and second embodiments, the clamping of the roller 140 by the drive gear 125 and the lock sleeve 145 is released along with the movement of the screw (spindle 160) during the screw tightening operation. Specifically, the roller is obtained by the resultant force of the urging force of the coil spring 155 in the axial direction of the spindle 160 and the axial reaction force of the spindle 160 that the lock sleeve 145 receives from the retainer 130 when the lock sleeve 145 rotates the retainer 130. The holding of 140 is released. That is, in order to release the clamping of the roller 140 only by the urging force of the coil spring 155, a large urging force of the coil spring 155 is required. However, by utilizing the reaction force that the lock sleeve 145 receives from the retainer 130, The clamping is reliably released, and the rotation transmission by the drive mechanism 120 is interrupted. In addition, a spring having a small spring constant can be applied to the coil spring 155 by utilizing the reaction force that the lock sleeve 145 receives from the retainer 130.

  Further, according to the first and second embodiments, the stopper 170 restricts the rotation of the spindle 160 in the screw tightening direction in the idling state. This reliably prevents the spindle 160 from unintentionally rotating due to, for example, a lubricant solidified in the front housing 104. Therefore, when performing the screw tightening operation, the spindle 160 is driven to rotate only when the spindle 160 is pressed. On the other hand, since the stopper 170 allows the rotation of the spindle 160 in the unscrewing direction, the spindle 160 is rotationally driven without pressing the spindle 160 when performing the screw removing operation. Thereby, the spindle 160 is rationally driven according to the work mode.

  Further, according to the first and second embodiments, since the oil seal 181 is provided on the front side of the front housing 104, the lubricant is prevented from flowing out from the front side of the front housing 104. This prevents contamination of the screw and workpiece. The oil seal 181 is prevented from coming off in the axial direction of the spindle 160 by elastic deformation of the base portion 181 a of the oil seal 181, and circumferential rotation associated with the rotation of the spindle 160 is restricted. In other words, the oil seal 181 is firmly fixed in the axial direction and the circumferential direction of the spindle 160. Further, since the recesses 104a and 104b are formed in the front housing 104, the movement of the oil seal 181 in the axial direction and the circumferential direction of the spindle 160 is more effectively restricted. The fixing of the oil seal 181 is particularly useful for the spindle 160 that rotates in the axial direction and is moved in the axial direction.

  Further, according to the first and second embodiments, the ventilation passage 190 suppresses the increase in the pressure of the air in the front housing 104. Further, the lubricant that has flowed out of the ventilation passage 190 is reliably captured by the oil filter 195, and the lubricant is prevented from flowing out of the screw driver 100. In the configuration in which the output shaft 111 of the motor 110 is disposed in parallel to the axial direction of the spindle 160 (tool bit 119), the motor 110 is disposed behind the drive mechanism 120 in consideration of the position of the center of gravity of the screw driver 100. . Therefore, an empty space is generated behind the drive mechanism 120 and above the motor 110. Since the ventilation passage 190 and the oil filter 195 are arranged in such an empty space, the components of the screw driver 100 are rationally arranged.

  In the above embodiment, the LED 107c is lit to notify that the unscrewing operation is performed. However, the present invention is not limited to this. For example, you may alert | report that the unscrewing operation | work is performed by blinking LED107c or changing the color of the light which LED107c emits. An actuator that generates vibration and sound may be provided as the rotation direction notification device. The rotation direction notifying device not only notifies the rotation of the spindle 160, 360 (tool bit 119) in the unscrewing direction at the time of screw removal work, but also the screw of the spindle 160, 360 (tool bit 119) at the time of screw tightening work. You may alert | report rotation of a tightening direction.

  In the above embodiment, the mechanical contact between the inclined portions 133a and 147a cooperates with the urging force of the coil spring 155 to release the holding of the roller 140 by the drive gear 125 and the lock sleeve 145. The lock sleeve 145 is moved forward, but is not limited thereto. That is, the lock sleeve 145 may be moved forward only by contacting the inclined portions 133a and 147a by appropriately setting the angles of the inclined surfaces of the inclined portions 133a and 147a. Further, for example, separately from the inclined portions 133a and 147a, it is detected that the locator 105 is in contact with the workpiece during the screw tightening operation, and the lock sleeve 145 is moved forward, so that the drive gear 125 and the lock sleeve are moved. A releasing means for releasing the holding of the roller 140 by 145 may be provided. Further, only one of the inclined portions 133a and the inclined portion 147a may be provided.

  Moreover, in the above embodiment, the inside of the drive gear 125 that is a drive member has a cylindrical shape, and the outside of the lock sleeve 145 that is a driven member is formed in a prismatic shape, but this is not a limitation. That is, the inside of the driving member may be a prismatic shape, and the outside of the driven member may be formed in a columnar shape.

In view of the gist of the present invention, the following aspects can be configured for the screw tightening tool according to the present invention. Each aspect is used not only alone or in combination with each other, but also in combination with the invention described in the claims.
(Aspect 1)
A two-sided width portion is formed in the large diameter portion.
(Aspect 2)
The movable member holding member is held in the housing by an O-ring as an elastic member.
(Aspect 3)
The holding area formed in the movable member holding member is formed as a groove.
(Aspect 4)
The first direction is set as a screw tightening direction in which the tip tool performs screw tightening work,
The second direction is set as an unscrewing direction in which the tip tool performs unscrewing work.
(Aspect 5)
The second region is formed as a pocket-shaped region that accommodates the movable member,
When the tip tool drive shaft rotates in the reverse direction,
The movable member is held in the pocket-shaped region so as not to be close to the tip tool drive shaft in the radial direction of the tip tool drive shaft.

(Correspondence between each component of this embodiment and each component of the present invention)
The correspondence between each component of the present embodiment and each component of the present invention is shown as follows. In addition, this embodiment shows an example of the form for implementing this invention, and this invention is not limited to the structure of this embodiment.
The screw driver 100 is an example of a configuration corresponding to the “screw tightening tool” of the present invention.
The front housing 104 is an example of a configuration corresponding to the “housing” of the present invention.
The motor 110 is an example of a configuration corresponding to the “motor” of the present invention.
The spindle 160 is an example of a configuration corresponding to the “tip tool drive shaft” of the present invention.
The large diameter portion 166 is an example of a configuration corresponding to the “large diameter portion” of the present invention.
The small diameter portion 167 is an example of a configuration corresponding to the “small diameter portion” of the present invention.
The stopper 170 is an example of a configuration corresponding to the “rotation restricting mechanism” of the present invention.
The ball holding ring 171 is an example of a configuration corresponding to the “movable member holding member” of the present invention.
The holding groove 172 is an example of a configuration corresponding to the “holding region” of the present invention.
The holding groove 172 is an example of a configuration corresponding to the “concave portion” of the present invention.
The ball 175 is an example of a configuration corresponding to the “movable member” of the present invention.

100 Screw Driver 101 Main Body 103 Main Housing 103a Partition Wall 103f Front 104 Front Housing 104a Recess 104b Recess 104c Large Diameter 105 Locator 106 External Communication Path 107 Handle 107a Trigger 107b Changeover Switch 107c LED
109 Power cable 110 Motor 111 Output shaft 112 Gear tooth 119 Tool bit 120 Drive mechanism 121 Needle bearing 122 Front bearing 123 Rear bearing 125 Drive gear 126 Bottom wall 127 Side wall 128 Gear tooth 130 Retainer 131 Base 131a Engagement hole 131b Ball holding part 132 1st side wall 133 2nd side wall 133a Inclination part 134 Roller holding part 139 Engagement pin 140 Roller 145 Lock sleeve 146 Roller engagement part 147 Retainer engagement part 147a Inclination part 150 Spring receiving member 150a Engagement hole 151 Roller engagement part 152 Ball contact portion 153 Ball 155 Coil spring 160 Spindle 161 Front shaft portion 162 Back shaft portion 162a Groove portion 163 Hollow portion 164 Communication hole 165 Rear end bearing 166 Large diameter portion 166b Width across flats 167 Small diameter portion 170 Stopper 171 Ball holding ring 172 Holding groove 172a Pocket-shaped region 173 Push ring 175 Ball 176 Ball 177 Leaf spring 177a Through hole 177b Engagement hole 180 O-ring 181 Oil seal 181a Base portion 181b Lip portion 190 Ventilation passage 191 Passage formation portion 191a Ventilation hole 195 Oil filter 271 Ball holding ring 272 Holding groove 272a Radial movement region

Claims (9)

A screw tightening tool that performs a predetermined operation by rotationally driving a tip tool that is detachably attached to the tip region,
A motor,
A tip tool that is rotationally driven by the motor in a predetermined forward rotation direction and a reverse rotation direction and is capable of rotationally driving the tip tool in a first direction corresponding to the forward rotation direction and a second direction corresponding to the reverse rotation direction. A drive shaft;
A rotation restricting mechanism that engages with the tip tool drive shaft to restrict the turn of the tip tool drive shaft;
The tip tool drive shaft is configured to be movable between a first position close to the tip region and a second position separated from the tip region with respect to the axial direction of the tip tool drive shaft.
The rotation restricting mechanism has a movable member that is movable between an engageable position that can be engaged with the tip tool drive shaft and an unengageable position that cannot be engaged with the tip tool drive shaft.
When the tip tool drive shaft is located at the first position, the movable member located at the engageable position engages with the tip tool drive shaft and rotates the tip tool drive shaft in the forward rotation direction. And the movable member is positioned at the non-engageable position to allow the tip tool drive shaft to rotate in the reverse rotation direction,
A screw tightening tool configured to allow rotation of the tip tool drive shaft in the forward rotation direction and the reverse rotation direction when the tip tool drive shaft is located at the second position. . The screw tightening tool according to claim 1,
The screw tightening tool, wherein the movable member moves in a circumferential direction around the tip tool drive shaft and is disposed at the engageable position and the non-engageable position. The screw tightening tool according to claim 1 or 2,
The movable member is configured to be switched between the engageable position and the non-engageable position based on rotation of the tip tool drive shaft when the tip tool drive shaft is positioned at the first position. Screw tightening tool characterized by being made. The screw tightening tool according to any one of claims 1 to 3,
The tip tool drive shaft has a large diameter portion and a small diameter portion formed in a region closer to the tip region than the large diameter portion,
The large diameter portion is engageable with the movable member when the movable member is located at the engageable position, and is engaged with the movable member when the movable member is located at the non-engageable position. Impossible,
The small diameter portion is not engageable with the movable member regardless of the position of the movable member,
When the tip tool drive shaft is located at the first position, the large diameter portion is disposed at a position corresponding to the movable member;
A screw tightening tool, wherein the small diameter portion is arranged at a position corresponding to the movable member when the tip tool drive shaft is located at the second position. The screw tightening tool according to any one of claims 1 to 4,
The rotation restricting mechanism is
A movable member holding member for holding the movable member;
The movable member is configured to be switched between the engageable position and the non-engageable position by moving in a holding region formed in the movable member holding member. Screw tightening tool. The screw tightening tool according to claim 5,
The holding region extends in a circumferential direction around the axis of the tip tool drive shaft, and the tip tool drive shaft is in a direction perpendicular to the axis direction of the tip tool drive shaft from the rotation axis of the tip tool drive shaft. A first region separated from the rotation axis by a first distance; and a second region connected to the first region and separated from the rotation axis of the tip tool drive shaft by a second distance longer than the first distance. Formed,
The position of the movable member arranged in the first region is set as the engageable position,
The screw tightening tool, wherein the position of the movable member arranged in the second region is set as the non-engageable position. The screw tightening tool according to claim 6,
In the second region, when the tip tool drive shaft rotates in the reverse rotation direction, the movable member disposed in the second region moves to the tip tool drive shaft with respect to the radial direction of the tip tool drive shaft. A screw tightening tool configured to hold the movable member so as not to be close to each other. The screw tightening tool according to any one of claims 5 to 7,
A housing that houses the tip tool drive shaft;
The rotation restricting mechanism is
An elastic member disposed between the movable member holding member and the housing;
The elastic member is configured to hold the movable member holding member in a fixed manner with respect to the housing, and to suppress vibration transmission from the movable member holding member to the housing. Fastening tool. The screw tightening tool according to claim 1,
The screw tightening tool, wherein the movable member is formed as a spherical body.

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