JP6422160B2 - Work tools - Google Patents

Description

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

  Japanese Patent Application Laid-Open No. 2012-135842 describes a screw driver that rotationally drives a driver bit. The screw driver is configured to transmit the rotation of the drive gear to the spindle by pushing the roller holding member while the roller rotates during the screw tightening operation.

JP 2012-135842 A

  However, in the screw driver, since the roller presses the roller holding member while rotating, it is necessary to take measures against wear of the roller and the roller holding member due to the rotation of the roller. The present invention has been made in view of the above, and an object of the present invention is to provide a technique for rationally transmitting the rotation of a motor to a tip tool in a work tool.

The above problems are solved by the present invention. According to a preferred embodiment of the work tool according to the present invention, the work tool that performs a predetermined work by rotating the tip tool removably attached to the tip region of the tool body around the long axis of the tip tool is configured. The The work tool includes a motor, a tip tool holding unit that holds the tip tool, a rotation drive mechanism that transmits rotation of the motor to the tip tool holding unit, and rotates the tip tool held by the tip tool holding unit. . The tip tool holding portion includes a frontmost position, a first position spaced rearward from the frontmost position, and a second position spaced rearward from the first position in the longitudinal direction of the tip tool . It is configured to be movable between. The first position is also referred to as the front position, and the second position is also referred to as the rear position. The tool body is typically configured as a housing that forms the outline of the work tool. Therefore, the tool body accommodates at least a motor, a tip tool holding portion, and a rotation drive mechanism.

  The rotational drive mechanism includes a drive member that is rotationally driven by a motor, a driven member that is connected to the tip tool holding portion, and a transmission member that is provided between the drive member and the driven member. The driven member is disposed coaxially with the driving member. In addition, the driven member and the tip tool holding part may be directly connected, or may be indirectly connected through an inclusion such as a gear mechanism. The transmission member can move between a clamping position between the driving member and the driven member and a non-clamping position in which the driving member and the driven member cannot be clamped about the rotation axis of the driving member. Typically, the transmission member and the driven member move relative to each other around the rotation axis of the drive member, so that the transmission member moves between the clamping position and the non-clamping position. The transmission member is preferably constituted by a rolling member such as a roller or a ball. The transmission member is clamped between the driving member and the driven member at the clamping position, and transmits the rotation of the driving member to the driven member. That is, the transmission member is sandwiched between the drive member and the driven member, and the drive member and the driven member can be rotated together via the transmission member. On the other hand, the transmission member blocks transmission of the rotation of the drive member to the driven member at a position where clamping is not possible.

In the present invention, in a state where the tip tool holding portion is located at the foremost position, the transmission member is placed at a position where it cannot be clamped, and transmission of rotational driving force in a predetermined forward direction and reverse direction to the tip tool holding portion is cut off. Configured to be. Furthermore, the tip tool holding portion in the state located at the first position, the transmission member is sandwiched driving member and the driven member in the clamping position, the tip tool holder is rotated in the reverse direction. On the other hand, the transmission member is held between the driving member and the driven member at the holding position in a state where the tip tool holding portion is located at the second position, and the tip tool holding portion is rotationally driven in the forward direction. Note that the tip tool holding portion may be further driven to rotate in the reverse direction in a state where the tip tool holding portion is located at the second position. Typically, the tip tool holding portion is allowed to rotate in a predetermined forward direction and in a reverse direction in a state of being positioned at the first position and the second position. Here, the rotational drive of the tip tool holding part means a drive in which a torque for performing a predetermined work is generated in the tip tool holding part. Further, the rotation permission of the tip tool holding portion is limited to driving in which the rotation of the tip tool holding portion is not restricted, the tip tool holding portion is rotatable, and torque for performing a predetermined work is generated. It is not a thing. Further, the holding position of the transmission member when the tip tool holding portion is rotationally driven in the forward direction (also referred to as a positive direction rotational drive possible position) and the transmission member when the tip tool holding portion is rotationally driven in the reverse direction. The clamping position (also referred to as a reverse rotation driving clamping position) may be the same position or a different position with respect to the driven member in the circumferential direction of the driving member. Regarding the rotation direction of the tip tool holding portion, for example, when the work tool is a screw tightening tool, the rotation direction of the tip tool holding portion (tip tool) for performing the screw tightening operation is defined as normal rotation. The rotation direction of the tip tool holding portion (tip tool) for performing the screw removal work is defined as reverse rotation. When the work tool is a drill, the rotation direction of the tip tool holding portion (tip tool) for performing the drilling operation is defined as normal rotation, and the tip tool caught in the work piece during the drilling operation is covered. The rotation direction of the tip tool holding part (tip tool) for removal from the workpiece is defined as the reverse direction.

  According to the present invention, the transmission member is switched between the clamping position and the clamping impossible position. Then, the transmission member is clamped between the driving member and the driven member at the clamping position to transmit the rotation of the driving member to the driven member. Therefore, wear of the transmission member is suppressed as compared with a configuration in which the rotation of the drive member is transmitted to the driven member while the transmission member rotates with respect to the drive member. For example, when the work tool is configured as a screw tightening tool, in the screw tightening operation, the tip tool is driven in the screw tightening direction (forward direction) by pressing the tip tool against the workpiece (screw). Is done. On the other hand, it is not reasonable to press the tip tool against the workpiece (screw) when performing the screw removal operation. Therefore, the tip tool is rotationally driven in the unscrewing direction (reverse direction) when positioned at the first position close to the tip region. Therefore, rational driving of the work tool according to the work mode can be realized.

Further, according to the present invention, the tip tool holding portion is configured to be restricted from rotating in the forward direction and in the reverse direction while being positioned at the foremost position . Typically, a rotation restricting portion attached to the tool body is provided. The rotation restricting portion engages with the tip tool holding portion located at the foremost position to restrict both the forward and reverse rotations of the tip tool holding portion. In this case, the tip tool holding portion includes an outer surface around the rotation axis of the tip tool holding portion, and the rotation restricting portion includes an inner surface that engages with the outer surface of the tip tool holding portion. Specifically, the cross-sectional shape of the inner surface of the rotation restricting portion orthogonal to the rotation axis of the tip tool holding portion is set as a non-circular cross-sectional shape. The noncircular cross-sectional shape suitably includes, for example, an oval cross section, an elliptical cross section, a rectangular cross section, and the like. Since the rotation of the tip tool holding portion is restricted at the foremost position, it is possible to prevent the tip tool holding portion from rotating together due to friction with the components of the drive mechanism.

According to the further form of the working tool which concerns on this invention, the urging | biasing member which urges | biases a front- end | tip tool holding part toward the foremost position is provided. Typically, the biasing member biases the tip tool holding portion so that the tip tool holding portion is positioned at the foremost position when the work tool is not driven. The rotational drive mechanism includes a switching member that is moved together with the tip tool holding portion when the tip tool holding portion is moved away from the foremost position against the biasing force of the biasing member. By the movement of the switching member, the position of the transmission member is switched from the unclampable position to the clamping position. The driven member and the switching member may be configured as a single member. According to this aspect, the position of the transmission member can be switched by moving the switching member in the major axis direction of the tip tool. In this case, the transmission member is moved around the long axis of the tip tool holding portion.

  According to the further form of the working tool which concerns on this invention, a rotational drive mechanism is equipped with the retainer holding a transmission member. A first engagement portion is formed on the retainer. On the other hand, the switching member is formed with a second engagement portion that can be engaged with the first engagement portion. At least one of the first engaging portion and the second engaging portion is constituted by a lead surface. In addition, the 1st engaging part and the 2nd engaging part may be comprised by the 1st lead surface and the 2nd lead surface, respectively. Typically, the lead surface is configured as a surface inclined in the major axis direction of the tip tool, for example, a spiral curved surface around the rotation axis of the drive member. The lead surface has a function of guiding the relative movement of the retainer with respect to the switching member. Therefore, the lead surface is also referred to as a guide surface.

When the tip tool holding portion is moved away from the foremost position in the longitudinal direction of the tip tool by pressing the tip tool held by the tip tool holding portion against the workpiece, the first engagement The retainer is moved relative to the switching member around the long axis of the tip tool by the engagement of the joint portion and the second engagement portion. Since the lead surface is formed, the retainer moves relative to the switching member around the long axis of the tip tool by moving the switching member together with the tip tool holding member in the long axis direction of the tip tool. Due to the movement of the retainer, the transmission member is moved from the non-clamping position to the clamping position. In other words, the transmission member is moved from the non-clamping position to the clamping position by the operator pressing the tip tool against the workpiece to perform a predetermined work. Thereby, rotation of a drive member is transmitted to a driven member, and a tip tool holding part is rotationally driven.

  On the other hand, when the pressing of the tip tool against the workpiece is released, the retainer moves relative to the switching member around the major axis of the tip tool by the engagement of the first engagement portion and the second engagement portion. By being moved, the transmission member is moved from the clamping position to the non-clamping position. That is, in order to finish a predetermined operation, the transmission member is moved from the clamping position to the non-clamping position by the operator releasing the pressing of the tip tool against the workpiece. Thereby, transmission of rotation of the drive member to the driven member is blocked. According to this aspect, the retainer can be moved around the long axis of the tip tool by the movement of the switching member by the lead surface (guide surface). Thereby, the transmission member can be rationally moved between the clamping position and the clamping impossible position.

  According to the further form of the working tool which concerns on this invention, the drive member is formed in the cylindrical shape. The rotational drive mechanism includes a retainer that holds a transmission member and a bearing that has an outer ring region that is inscribed in the drive member, and is disposed coaxially with the drive member in a cylindrical inner space of the drive member. The retainer is connected to the outer ring region of the bearing and is configured to be rotatable by a drive member. The retainer may be disposed so as to abut on the outer ring region of the bearing, or may be disposed such that inclusions such as washers are interposed between the retainer and the outer ring region of the bearing. The retainer is configured to be rotatable by a frictional force generated between the retainer and the outer ring region. Typically, the position of the transmission member is preferably switched by the rotation of the retainer due to the frictional force.

  According to the present invention, a technique for rationally transmitting the rotation of a motor to a tip tool is provided.

It is a side view showing the whole screw driver composition concerning a typical embodiment of the present invention. It is a fragmentary sectional view of the screw driver of Drawing 1, and shows the state where a spindle is located in a front position. It is a side view of a drive mechanism. It is a perspective view of a retainer. It is a perspective view of a retainer. It is an expanded view of a retainer and a spring receiving member. It is sectional drawing in the VII-VII line of FIG. It is a perspective view of a lock sleeve. It is sectional drawing in the XI-XI line of FIG. It is sectional drawing in the XX line of FIG. It is a perspective view of a spindle. It is a perspective view of a stopper. It is sectional drawing in the XIII-XIII line | wire of FIG. In FIG. 13, it is sectional drawing which shows the state in which rotation of the spindle was controlled by the stopper. FIG. 3 is a cross-sectional view corresponding to FIG. 2, showing a state where the spindle is located at the first rear position. It is an expanded view of a retainer. It is sectional drawing in the XVII-XVII line of FIG. FIG. 3 is a cross-sectional view corresponding to FIG. 2, showing a state where the spindle is located at the second rear position. It is an expanded view of a retainer, and is a figure which shows the state in which the retainer was rotated to the normal direction. It is an expanded view of a retainer, and is a figure which shows the state in which the retainer was rotated in the reverse direction. FIG. 8 is a cross-sectional view corresponding to FIG. 7, showing a state in which the retainer and the roller are rotated in the reverse direction with respect to the spring receiving member. It is sectional drawing equivalent to FIG. 10 which shows the state in which the retainer and the roller were rotated in the reverse direction with respect to the spring receiving member. FIG. 3 is a cross-sectional view corresponding to FIG. 2, showing a state where the spindle is located at a rear third position. It is an expanded view of a retainer, and is a figure which shows the state in which the retainer was rotated to the normal direction. It is an expanded view of a retainer, and is a figure which shows the state in which the retainer was rotated in the reverse direction. FIG. 8 is a cross-sectional view corresponding to FIG. 7 illustrating a state in which the retainer and the roller are rotated in the forward direction with respect to the lock sleeve. FIG. 10 is a cross-sectional view corresponding to FIG. 9 showing a state in which the retainer and the roller are rotated in the forward direction with respect to the lock sleeve.

  A representative embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, as an example of a work tool, a screw driver 100 that performs a predetermined work on a workpiece such as a gypsum board is configured. 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 and 2, the main body 101 is mainly configured by 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 a drive mechanism 120 that rotationally drives the spindle 160. The main body 101 is an implementation configuration example corresponding to the “tool main body” in the present invention.

  As shown in FIG. 2, 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 on the partition wall 103 a and a bearing (not shown) held on 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 spindle 160 such 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. Thereby, the screw tightening depth is set.

  As shown in FIG. 1, 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. This motor 110 is an implementation structural example corresponding to the "motor" in this invention.

[Drive mechanism]
As shown in FIGS. 2 and 3, 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, and the like. In FIG. 3, the drive gear 125 is not shown. This drive mechanism 120 is an implementation configuration example corresponding to the “rotary drive mechanism” in the present invention.

[Drive gear]
As shown in FIG. 2, 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 bearing 123, 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. The bearing 123 holds the spindle 160 rotatably. The bearing 123 includes a spacer 124 attached to the outer ring of the bearing 123. That is, the spacer 124 is provided so as to rotate integrally with 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). This drive gear 125 is an implementation configuration example corresponding to the “drive member” in the present invention. The bearing 123 is an implementation configuration example corresponding to the “bearing” in the present invention.

[Retainer]
As shown in FIGS. 2 to 5, 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. The base 131 is formed with a contact portion 131A that protrudes rearward from the rear surface of the retainer 130. The contact portion 131A is configured to contact a spacer 124 attached to the outer ring of the bearing 123.

  As shown in FIGS. 2, 4 and 5, the base 131 is provided with a through hole through which the rear shaft 162 of the spindle 160 passes. As shown in FIGS. 4 and 5, engagement holes 131 a and 131 b having a predetermined length in the circumferential direction of the spindle 160 are provided in the through hole of the base portion 131. A cylindrical engagement pin 138 is held in the engagement hole 131a. The engagement pin 138 is held in parallel with the major axis direction of the spindle 160. An engagement ball 139 is held in the engagement hole 131b so as to be movable along with the spindle 160 in the major axis direction of the spindle 160.

  As shown in FIG. 6, the engagement hole 131a is configured as a groove having a certain width in the axial direction of the retainer 130 (the vertical direction in FIG. 6). That is, with respect to the circumferential direction of the retainer 130, the engagement pin 138 can move in the engagement hole 131a. On the other hand, the engagement hole 131b is configured as a groove having different widths on the front side (upper side in FIG. 6) and the rear side (lower side in FIG. 6, on the bearing 124 side) of the retainer 130 in the axial direction of the retainer 130. Specifically, an inclined portion is set in the second region 131b2 such that the length of the retainer 130 in the circumferential direction of the rear third region 131b3 is larger than that of the front first region 131b1. The width of the first region 131b1 is set to be substantially the same as the diameter of the engagement ball 139. That is, the movement of the engagement ball 139 in the first region 131b1 is restricted in the circumferential direction of the retainer 130. On the other hand, with respect to the circumferential direction of the retainer 130, the engagement balls 139 can move in the second region 131b2 and the third region 131b3, respectively.

  As shown in FIGS. 2 and 7, corresponding to the engagement holes 131 a and 131 b, the spindle 160 is formed with a groove portion 162 a extending in the axial direction and a ball engagement portion 162 b facing the groove portion 162 a. As shown in FIG. 7, the cross section perpendicular to the axial direction of the spindle 160 of the groove 162a and the ball engaging portion 162b corresponds to the cylindrical engaging pin 138 and the engaging ball 139 that connect the spindle 160 and the retainer 130, respectively. Thus, it is formed in a substantially semicircular shape.

  As shown in FIG. 6, when the engagement ball 139 is positioned in the first region 131b1 of the engagement hole 131b, the retainer 130 and the spindle 160 are rotated together by the engagement ball 139 as shown in FIG. Retained. FIG. 6 shows the position of the engagement ball 139 in a state where the spindle 160 is located in the foremost position. On the other hand, in a state where the engagement ball 139 is located in the second region 131b2 or the third region 131b3, the engagement pin 138 can move in the engagement hole 131a with respect to the circumferential direction of the retainer 130. Since each can move within the second region 131b2 or the third region 131b3, the retainer 130 and the spindle 160 rotate relatively within the moving range of the engaging pin 138 and the engaging ball 139.

  As shown in FIGS. 3 and 4, 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 of the retainer 130 (the front-rear direction of the screw driver 100). Has been. 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. 4, a predetermined space is formed between the first side wall 132 and the second side wall 133 in the circumferential direction of the retainer 130. This predetermined space is defined as a roller holding portion 134 for holding the roller 140. Accordingly, the retainer 130 holds the four rollers 140 between the first side wall 132 and the second side wall 133. This retainer 130 is an implementation configuration example corresponding to the “retainer” in the present invention. In addition, the roller 140 is an implementation configuration example corresponding to the “transmission member” in the present invention.

  As shown in FIGS. 3 and 4, 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 133 a are configured as lead surfaces formed along the circumferential direction of the retainer 130. The two inclined portions 133a are formed to be inclined at 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. That is, the two inclined portions 133a are formed in a double spiral shape. This inclined portion 133a is an implementation configuration example corresponding to the “first engaging portion” and the “lead surface” in the present invention.

[Lock sleeve]
As shown in FIGS. 2, 3 and 8, 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 corresponds to the six sides of the hexagon, and can be contacted and separated in the axial direction of the four roller engaging portions 146 that can be engaged with the roller 140, the second side wall 133 of the retainer 130, and the spindle 160. Two retainer engaging portions 147 are provided. The lock sleeve 145 is an implementation configuration example corresponding to the “driven member” and the “switching member” in the present invention.

  As shown in FIG. 9, the roller engaging portion 146 is configured by four planes each 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.

  As shown in FIG. 9, 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 with respect to the radial direction of the retainer 130 (the radial direction of the spindle 160). Yes. As shown in FIG. 8, with respect to the longitudinal direction of the screw driver 100, the rear end portion of the retainer engaging portion 147 is configured with an inclined surface that is inclined with respect to the rotation axis of the spindle 160 (the central axis of the lock sleeve 145). An 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 147 a are configured as lead surfaces formed along the circumferential direction around the axial direction of the lock sleeve 145. The two inclined portions 147a are formed so as to be inclined at the same angle with respect to the outline (outer periphery) of the retainer engaging portion 147 in a cross section orthogonal to the axial direction of the lock sleeve 145. That is, the two inclined portions 147a are formed in a double spiral shape. This inclined portion 147a is an implementation configuration example corresponding to the “second engaging portion” and the “lead surface” in the present invention.

[Spring receiving member]
As shown in FIGS. 2 and 10, the spring receiving member 150 is a member having a substantially hexagonal cross section. The spring receiving member 150 is accommodated in 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 of the screw driver 100. The spring receiving member 150 has a through hole through which the spindle 160 passes. A substantially semicircular engagement hole 150a is formed in the through hole. As a result, the engagement pin 138 disposed in the groove portion 162 a of the rear shaft portion 162 of the spindle 160 engages with the engagement hole 150 a of the spring receiving member 150. Therefore, the spring receiving member 150 is connected to the spindle 160 so as to rotate integrally with the spindle 160 at all times. 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. Each of the roller engaging portions 151 is formed as a plane parallel to the rotation axis of the spindle 160. This spring receiving member 150 is an implementation structural example corresponding to the “driven member” in the present invention.

[Coil spring]
As shown in FIGS. 2 and 3, the coil spring 155 is arranged 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 coil spring 155 urges the spring receiving member 150, the retainer 130, and the drive gear 125 toward the rear. This coil spring 155 is an implementation structural example corresponding to the “biasing member” in the present invention.

[spindle]
As shown in FIGS. 2, 3, and 11, the spindle 160 is a long columnar member made of metal. The spindle 160 is provided so as to be movable in the front-rear direction of the screw driver 100 (long axis direction of the spindle 160). 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 front shaft portion 161 is provided with a ball and a leaf spring. Thereby, the ball urged by the leaf spring is engaged with the tool bit 119, and the tool bit 119 is held by 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 FIG. 2, an oil seal 181 interposed between the front housing 104 and the front shaft portion 161 is provided 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 supported so as to be slidable and rotatable in the front-rear direction with respect to a cylindrical rear end bearing 165 provided on the partition wall 103 a of the main housing 103. 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. When the rear end portion of the groove portion 162a contacts the engaging pin 138, the forward movement of the spindle 160 in the axial direction is restricted. On the other hand, the engagement pin 138 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.

  As shown in FIG. 2, a hollow portion 163 that opens to the rear end surface of the rear shaft portion 162 and extends in the major axis direction inside 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. Thereby, 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. Therefore, 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.

  As shown in FIG. 2, an engagement portion 166 that can be engaged with the stopper 170 and a non-engagement portion 167 that cannot be engaged with the stopper 170 are formed in the rear end region of the front shaft portion 161. . As shown in FIG. 11, the engaging portion 166 is formed in a rectangular column shape with a rectangular cross section, and the non-engaging portion 167 is formed in a cylindrical shape with a circular cross section. The distance between the opposing sides of the square cross section of the engaging portion 166 is set to be substantially the same as the diameter of the circular cross section of the non-engaging portion 167. Accordingly, the length of the diagonal line of the square section of the engaging portion 166 is longer than the diameter of the circular section of the non-engaging portion 167. The outer surface of the engaging portion 166 is an implementation configuration example corresponding to the “outer surface” in the present invention.

[Stopper]
As shown in FIG. 12, the stopper 170 is formed as a substantially cylindrical member. A through hole 170 </ b> A through which the front shaft portion 161 of the spindle 160 passes is formed inside the stopper 170. This through-hole 170A includes a curved surface region 172 that connects two planar regions 171 and the planar region 171 facing each other. The two planar regions 171 are configured as surfaces parallel to each other and parallel to the axial direction of the spindle 160. Further, the two curved surface regions 172 are also configured as surfaces parallel to the axial direction of the spindle 160. This stopper 170 is an implementation structural example corresponding to the “rotation restricting portion” in the present invention. Further, the planar region 171 constituting the through hole 170A is an implementation configuration example corresponding to the “inner surface” in the present invention.

  A recess 173 is formed on the outer periphery of the stopper 170. As shown in FIGS. 13 and 14, the concave portion 173 engages with the convex portion 104 a formed in the front housing 104, and the rotation of the stopper 170 about the spindle 160 is restricted. That is, the stopper 170 is attached to the front housing 104 in a state where the rotation is restricted.

  As shown in FIG. 13, the curved surface region 172 of the through hole 170 </ b> A has an arc shape that is a part of a circle having a diameter longer than the diagonal length in the square cross section of the engaging portion 166 in the cross section orthogonal to the axial direction of the spindle 160. Is formed. Therefore, when the spindle 160 is rotated from the position shown in FIG. 13 to the position shown in FIG. 14 with the engaging portion 166 of the spindle 160 positioned in the through hole 170A of the stopper 170, the engaging portion 166 of the spindle 160 is The rotation of the spindle 160 is restricted by engaging (contacting) the flat area 171 of the stopper 170. Note that the engaging portion 166 of the spindle 160 does not engage (contact) the curved surface region 172 of the stopper 170. That is, in a state where the spindle 160 is located at the foremost position, the spindle 160 abuts against the stopper 170 and is restricted from rotating. The engaged portion 167 of the spindle 160 does not engage with the through hole 170A of the stopper 170. Therefore, when the spindle 160 is moved rearward and the non-engaging portion 167 is disposed in the through hole 170A of the stopper 170, the rotation of the spindle 160 is not hindered and the spindle 160 can rotate in any direction. .

[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. That is, the tool bit 119 (spindle 160) is rotationally driven in a predetermined direction (hereinafter referred to as a positive direction), and screw tightening work is performed. On the other hand, the tool bit 119 (spindle 160) is rotationally driven in a direction opposite to a predetermined direction (hereinafter referred to as a reverse direction), and a screw removal operation is performed. The rotational drive of the spindle 160 is switched according to the position of the spindle 160 in the front-rear direction of the screw driver 100. The forward direction and the reverse direction with respect to the rotational driving direction of the spindle 160 are implementation examples corresponding to the “forward direction” and the “reverse direction” in the present invention, respectively.

(When the spindle is in the forward position)
Specifically, FIGS. 2 to 14 show a state in which the spindle 160 is located in the foremost direction in the front-rear direction of the screw driver 100. The position of the spindle 160 is also referred to as a front position. This forward position is an implementation configuration example corresponding to the “ frontmost position ” in the present invention. In the state where the spindle 160 is located at the front position, as shown in FIG. 3, the inclined portion 147 a of the retainer engaging portion 147 of the lock sleeve 145 does not contact the inclined portion 133 a of the retainer 130. Therefore, as shown in FIG. 9, the roller 140 is maintained in a substantially central region of the roller engaging portion 146 in the circumferential direction of the spindle 160. In a substantially central region of the roller engaging portion 146, the roller 140 is set so as not to be sandwiched between the lock sleeve 145 and the side wall 127 of the drive gear 125. The substantially central region of the roller engaging portion 146 is also referred to as a roller non-clamping position or a rotation transmission impossible position in the roller engaging portion 146. This rotation transmission impossibility position is an implementation configuration example corresponding to the “clamping impossibility position” in the present invention.

  In the state where the spindle 160 is located at the front position, as shown in FIGS. 6 and 7, the engaging ball 139 engages with the retainer 130 and the spindle 160, and the retainer 130 and the spindle 160 are integrated. Further, as shown in FIG. 10, the spindle 160 and the spring receiving member 150 are integrated with each other by the engagement pin 138. Therefore, the relative position of the roller 140 held by the retainer 130 and the spring receiving member 150 does not change with respect to the circumferential direction of the spindle 160. At this time, the roller 140 is maintained in a substantially central region of the roller engaging portion 151. In a substantially central region of the roller engaging portion 151, the roller 140 is set so as not to be sandwiched between the spring receiving member 150 and the side wall 127 of the drive gear 125. The substantially central region of the roller engaging portion 151 is also referred to as a roller non-clamping position or a rotation transmission impossible position in the roller engaging portion 151. This rotation transmission impossibility position is an implementation configuration example corresponding to the “clamping impossibility position” in the present invention.

  As described above, the roller 140 is maintained at the roller non-clamping position in the roller engaging portion 146 and the roller engaging portion 151. Therefore, in the state where the spindle 160 is located at the front position, the rotation of the drive gear 125 is not transmitted to the spindle 160 via the roller 140.

  On the other hand, the rotation of the drive gear 125 in the positive direction is caused by the frictional force between the spacer 124 attached to the outer ring of the bearing 123 and the contact portion 131A of the retainer 130 that contacts the spacer 124, and the engagement pin 138. It is transmitted to the spindle 160 through the joint ball 139. Further, the reverse rotation of the drive gear 125 is transmitted to the spindle 160 via the frictional force between the spacer 124 and the contact portion 131 </ b> A and the engagement ball 139. At this time, as shown in FIG. 14, the engaging portion 166 of the spindle 160 is engaged with the stopper 170, and the rotation of the spindle 160 is restricted. That is, the stopper 170 restricts the rotation of the spindle 160 against the frictional force between the spacer 124 and the contact portion 131A. In FIG. 14, the forward rotation of the spindle 160 is restricted, but the reverse rotation of the spindle 160 is also restricted by the engagement of the engaging portion 166 and the stopper 170. As described above, when the spindle 160 is located at the front position, the forward rotation and the reverse rotation of the spindle 160 are restricted. That is, when the spindle 160 is located at the front position, the screw tightening operation and the screw removing operation are not performed.

(When the spindle is in the first rear position)
15 to 17 show a state where the screw (not shown) at the tip of the tool bit 119 is further pressed against the workpiece, and the spindle 160 has moved backward from the front position in the front-rear direction of the screw driver 100. Is shown. The position of the spindle 160 is also referred to as a first rear position. As shown in FIGS. 15 and 16, when the spindle 160 is moved from the front position to the first rear position, the engagement ball 139 is also moved rearward. Also in the first rear position of the spindle 160, the inclined portion 147a of the retainer engaging portion 147 of the lock sleeve 145 does not come into contact with the inclined portion 133a of the retainer 130, similarly to the front position of the spindle 160. Therefore, similarly to the case where the spindle 160 is located at the front position, the roller 140 is maintained at the roller non-clamping position in the roller engaging portion 146 (see FIG. 9).

  At this time, the engagement ball 139 is moved backward, but is still located in the first region 131b1 of the engagement hole 131b. In the first region 131b1, the engagement ball 139 engages with the retainer 130 and the spindle 160, and the retainer 130 and the spindle 160 are integrated. Therefore, the relative position of the roller 140 held by the retainer 130 and the spring receiving member 150 does not change with respect to the circumferential direction of the spindle 160. Therefore, similarly to the case where the spindle 160 is located at the front position, the roller 140 is maintained at the roller non-clamping position in the roller engaging portion 151 (see FIG. 10).

  As described above, the roller 140 is maintained at the roller non-clamping position in the roller engaging portion 146 and the roller engaging portion 151. Therefore, in the state where the spindle 160 is located at the first rear position, the rotation of the drive gear 125 is not transmitted to the spindle 160 via the roller 140.

  On the other hand, as shown in FIG. 17, the non-engaging portion 167 of the spindle 160 is disposed in the through hole 170 </ b> A of the stopper 170 in the first rear position of the spindle 160. That is, the rotation restriction of the spindle 160 by the stopper 170 is released. At this time, the rotation of the drive gear 125 is caused by the friction force between the spacer 124 attached to the outer ring of the bearing 123 and the contact portion 131A of the retainer 130 contacting the spacer 124, and the spindle 160 via the engagement ball 139. Is transmitted to.

  Therefore, when the spindle 160 is located at the first rear position, the spindle 160 is rotated in the forward direction or the reverse direction by the action of the frictional force between the spacer 124 and the contact portion 131A. However, a setting is made so that a frictional force that causes a torque to be applied to the spindle 160 so that the tool bit 119 is screwed or unscrewed is not generated between the spacer 124 and the contact portion 131A. Has been. In other words, the spindle 160 only rotates together with the drive gear 125 by the frictional force, and no torque that allows the tool bit 119 to perform the screwing operation or the screw removing operation is applied. That is, when the spindle 160 is located at the first rear position, the tool bit 119 (spindle 160) is rotated in the forward direction or the reverse direction, but the tool bit 119 performs the screw tightening operation and the screw removing operation. The necessary torque is not applied, and the screw tightening and unscrewing operations are not performed. Accordingly, the first rear position is also referred to as a neutral position.

(When the spindle is in the second rear position)
18 to 22, the screw (not shown) at the tip of the tool bit 119 is further pressed against the workpiece, and the spindle 160 moves backward from the first rear position in the front-rear direction of the screw driver 100. Is shown. The position of the spindle 160 is also referred to as a second rear position. This rear second position is an implementation configuration example corresponding to the “first position” in the present invention. As shown in FIGS. 18 to 20, when the spindle 160 is moved from the first rear position to the second rear position, the engagement ball 139 is also moved rearward. Also in the second rear position of the spindle 160, the inclined portion 147a of the retainer engaging portion 147 of the lock sleeve 145 does not contact the inclined portion 133a of the retainer 130, similarly to the front position and the first rear position of the spindle 160. . Therefore, as in the case where the spindle 160 is located at the front position and the first rear position, the roller 140 is maintained at the roller non-clamping position in the roller engaging portion 146 (see FIG. 9).

  At this time, the engagement ball 139 is moved rearward and is positioned in the second region 131b2 of the engagement hole 131b. With the engagement ball 139 positioned in the second region 131b2, the retainer 130 is moved in the forward direction indicated by the arrow A (hereinafter also referred to as the A direction) via the spacer 124 by the drive gear 125 as shown in FIG. When rotated, the engagement pin 138 and the engagement ball 139 do not move in the engagement holes 131a and 131b. That is, the retainer 130 and the spindle 160 do not move relative to each other in the circumferential direction. That is, similarly to the case where the spindle 160 is located at the front position and the first rear position, the roller 140 is maintained at the roller non-clamping position in the roller engaging portion 151 (see FIG. 10).

  On the other hand, with the engagement ball 139 positioned in the second region 131b2, the retainer 130 is moved in the reverse direction indicated by the arrow B (hereinafter also referred to as the B direction) through the spacer 124 by the drive gear 125 as shown in FIG. ), The engagement pin 138 and the engagement ball 139 move in the engagement holes 131a and 131b. That is, the retainer 130 and the spindle 160 move relative to each other in the circumferential direction. Specifically, as shown in FIGS. 21 and 22, the retainer 130 is rotated relative to the spindle 160 in the B direction. Therefore, the roller 140 held by the retainer 130 is moved in the circumferential direction with respect to the spring receiving member 150 held integrally with the spindle 160, and the roller 140 is moved between the roller engaging portion 151 and the side wall 127 of the drive gear 125. Sandwiched between. At this time, 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. As a result, the rotation of the drive gear 125 is transmitted to the spindle 160, and the tool bit 119 is rotationally driven in the reverse direction. As a result, unscrewing work is performed by the tool bit 119. Note that the position at which the roller 140 is sandwiched between the drive gear 125 and the spring receiving member 150 (roller engaging portion 151) to generate the wedge effect (the position shown in FIG. 22) is the roller clamping position at the roller engaging portion 151, Or it is also called a rotation transmission position. This rotation transmission position is an implementation configuration example corresponding to the “clamping position” in the present invention.

  As described above, when the spindle 160 is positioned at the second rear position, the screw removal operation is performed by the tool bit 119, but the screw tightening operation is not performed. That is, when the spindle 160 is located at the second rear position, the drive mechanism 120 transmits a torque capable of performing the screw removal operation to the tool bit 119, but transmits a torque capable of performing the screw tightening operation. do not do.

(When the spindle is located at the third rear position)
23 to 27, the screw (not shown) at the tip of the tool bit 119 is further pressed against the workpiece, and the spindle 160 moves backward from the second rear position in the front-rear direction of the screw driver 100. Is shown. The position of the spindle 160 is the rearmost position of the spindle 160 and is also referred to as a rear third position. This rear third position is an implementation configuration example corresponding to the “second position” in the present invention.

  As shown in FIGS. 23 to 25, when the spindle 160 is moved from the second rear position to the third rear position, the engagement ball 139 is also moved rearward. In the third rear position, the inclined portion 147 a of the retainer engaging portion 147 of the lock sleeve 145 contacts the inclined portion 133 a of the retainer 130. Due to the contact between the inclined portion 133a and the inclined portion 147a, as shown in FIGS. 26 and 27, the lock sleeve 145 is rotated in the circumferential direction with respect to the retainer 130, and the side wall 127 of the drive gear 125 and the lock sleeve 145 are A roller 140 is sandwiched therebetween. At this time, the roller 140 acts as a wedge, and the drive gear 125 and the lock sleeve 145 are integrated via the roller 140.

  Further, the spring receiving member 150 and the spindle 160 are integrated with the drive gear 125 and the lock sleeve 145 via the retainer 130 that holds the roller 140. As a result, the forward rotation of the drive gear 125 is transmitted to the spindle 160, and the tool bit 119 is rotationally driven in the forward direction. The position at which the roller 140 is sandwiched between the drive gear 125 and the lock sleeve 145 (roller engaging portion 146) to generate the wedge effect (the position shown in FIG. 27) is the roller clamping position at the roller engaging portion 146, or Also referred to as a rotation transmission position. This rotation transmission position is an implementation configuration example corresponding to the “clamping position” in the present invention. In this case, the roller 140 is disposed at the roller clamping position by the spindle 160 being moved rearward and the lock sleeve 145 moving relative to the retainer 130 in the circumferential direction.

  Specifically, when the drive gear 125 (retainer 130) is rotated in the forward direction (A direction), as shown in FIG. 24, the engagement pin 138 and the engagement ball 139 are connected to the engagement holes 131a, It contacts the rear wall surface in the rotational direction of 131b. Thereby, the retainer 130 and the spindle 160 are integrated via the engagement pin 138 and the engagement ball 139. As a result, the roller 140 is sandwiched between the drive gear 125 and the lock sleeve 145 by the engagement of the inclined portions 133a and 147a, and the drive gear 125 and the lock sleeve 145 are integrated, and the engagement pin 138 and the engagement ball 139 The retainer 130 and the spindle 160 are integrated. As a result, the rotation of the drive gear 125 in the positive direction is transmitted to the spindle 160, and screw tightening is performed by the tool bit 119 based on the rotation of the spindle 160 (drive gear 125) in the positive direction.

  On the other hand, when the drive gear 125 (retainer 130) is rotated in the reverse direction (direction B), as described above, in the state where the engagement ball 139 is positioned in the second region 131b2 in the second rear position, The retainer 130 is rotated relative to the B in the B direction, and the roller 140 is sandwiched between the roller engaging portion 151 and the side wall 127 of the drive gear 125. In this state, when the spindle 160 is moved from the second rear position to the third rear position, the engagement ball 139 moves rearward as shown in FIG. 25, but the spindle 160 is located at the second rear position. As in the case, the roller 140 is sandwiched between the drive gear 125 and the spring receiving member 150. Thereby, the drive gear 125 and the spring receiving member 150 are integrated. In other words, when the spindle 160 is located at the rear third position and the drive gear 125 (retainer 130) is rotated in the reverse direction, the roller 140 is moved in the same manner as when the spindle 160 is located at the rear second position. The drive gear 125 and the spring receiving member 150 are sandwiched. As a result, the reverse rotation of the drive gear 125 is transmitted to the spindle 160 via the spring receiving member 150, and the tool bit 119 performs the screw removal operation based on the reverse rotation of the spindle 160 (drive gear 125). Is called.

  In the screw tightening operation, 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 third rear position shown in FIG. 23 toward 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 in the axial direction of the spindle 160.

  The urging force of the coil spring 155 acts forward on the spindle 160 via the lock sleeve 145. 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 third rear position shown in FIG. 23 by (the 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. That is, 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 clamping 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. Thereby, the rotation transmission from the drive gear 125 to the spindle 160 is interrupted, and the screw tightening operation is completed.

  As described above, the drive of the tool bit 119 corresponding to the position of the spindle 160 in the front-rear direction of the screw driver 100 is controlled by the drive mechanism 120 and the stopper 170. That is, (1) When the spindle 160 is located at the front position, the rotation of the tool bit 119 is restricted. Further, (2) when the spindle 160 is located at the first rear position, the tool bit 119 is allowed to rotate. Further, (3) when the spindle 160 is located at the second rear position, the tool bit 119 is driven to rotate in the reverse direction according to the rotation direction of the motor 110, but not rotated in the forward direction. Further, (4) when the spindle 160 is located at the third rear position, the tool bit 119 is driven to rotate in the forward direction or the reverse direction according to the rotation direction of the motor 110. In other words, the drive mechanism 120 performs the screw removal operation by rotating the tool bit 119 in the reverse direction at a predetermined first push amount with respect to the push amount of the spindle 160, and at a second push amount larger than the first push amount. The tool bit 119 is rotationally driven in the forward direction to perform a screw tightening operation.

  According to the above-described embodiment, when the screw tightening operation is performed, the spindle 160 is pressed and moved to the rear position, whereby the roller is engaged by the engagement between the inclined portion 147a of the lock sleeve 145 and the inclined portion 133a of the retainer 130. 140 is moved in the circumferential direction of the retainer 130 with respect to the lock sleeve 145. 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 present embodiment, by using the roller 140, the output shaft 111 of the motor 110 is caused by the wedge effect of the drive gear 125 and the lock sleeve 145 or the roller 140 sandwiched between the drive gear 125 and the spring receiving member 150. Is reliably transmitted to the spindle 160. Further, since the roller 140 does not rotate when the rotation of the drive gear 125 is transmitted to the spindle 160, wear of the roller 140 is suppressed.

  Further, according to the present embodiment, during the screw tightening operation, the holding of the roller 140 by the drive gear 125 and the lock sleeve 145 is released with the movement of the screw (spindle 160). 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 present embodiment, in a state where the tool bit 119 is not pressed against the non-working material (idling state), the stopper 170 is in the direction opposite to the forward direction (screw tightening direction) of the spindle 160 (screw unscrewing direction). Regulate the rotation of Thereby, for example, the spindle 160 is prevented from unintentionally rotating (co-rotation) by the lubricant solidified in the front housing 104 or the like.

  In the screw tightening operation, the tool bit 119 is driven in the screw tightening direction (forward direction) by pressing the tool bit 119 (spindle 160) against the workpiece (screw). On the other hand, when the screw removing operation is performed, a force for pressing the tool bit 119 in the screw tightening operation is not necessary. That is, when performing the screw removal operation, a slight pressing force is required to maintain the engagement between the tool bit 119 and the screw, but no pressing force is required when performing the screw tightening operation. In view of this point, according to the present embodiment, the spindle 160 and the tool bit 119 are rotationally driven in the unscrewing direction (reverse direction) when the spindle 160 is located at the second rear position close to the tip region. In other words, the screw removing operation is performed with a pressing force smaller than the pressing force when performing the screw tightening operation. Thereby, the rational drive of the screw driver 100 according to a work mode is realizable.

  In the above-described embodiment, the mechanical contact between the inclined portions 133a and 147a cooperates with the biasing force of the coil spring 155 to release the holding of the roller 140 by the drive gear 125 and the lock sleeve 145. Although the lock sleeve 145 has been moved forward, the present invention is not limited to this. 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.

  Further, in the above embodiment, the inside of the drive gear 125 that is a drive member is cylindrical, 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.

  Moreover, in the above embodiment, although demonstrated using the screwdriver as a work tool, it is not restricted to this. For example, the present invention may be applied to an electric drill as long as the tip tool is rotationally driven.

In view of the gist of the present invention, the following modes can be configured for the work 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)
The driven member is composed of a first driven member and a second driven member,
When the tip tool holding portion is located at the first position, the transmission member is sandwiched between the driving member and the first driven member at the clamping position, and the rotation of the driving member is transmitted to the first driven member.
When the tip tool holding portion is positioned at the second position, the transmission member is clamped between the driving member and the second driven member at the clamping position, and the rotation of the driving member is transmitted to the second driven member.
(Aspect 2)
A predetermined first position of the transmission member relative to the driven member is set as a first clamping position;
A predetermined second position different from the first position of the transmission member relative to the driven member is set as the second clamping position;
The transmission member is clamped between the driving member and the driven member at the first clamping position, the rotation of the driving member is reached to the driven member, and the tip tool holding portion is rotationally driven in the reverse direction.
The transmission member is clamped between the driving member and the driven member at the second clamping position, and the rotation of the driving member reaches the driven member, and the tip tool holding portion is rotationally driven in the forward direction.
(Aspect 3)
The driven member has a rectangular cross section perpendicular to the long axis direction of the tip tool holding portion.

(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 “work tool” of the present invention.
The main body 101 is an example of a configuration corresponding to the “tool main body” of the present invention.
The motor 110 is an example of a configuration corresponding to the “motor” of the present invention.
The drive mechanism 120 is an example of a configuration corresponding to the “rotary drive mechanism” of the present invention.
The drive gear 125 is an example of a configuration corresponding to the “drive member” of the present invention.
The retainer 130 is an example of a configuration corresponding to the “retainer” of the present invention.
The inclined portion 133a is an example of a configuration corresponding to the “first engagement portion” of the present invention.
The roller 140 is an example of a configuration corresponding to the “transmission member” of the present invention.
The lock sleeve 145 is an example of a configuration corresponding to the “driven member” of the present invention.
The lock sleeve 145 is an example of a configuration corresponding to the “switching member” of the present invention.
The inclined portion 147a is an example of a configuration corresponding to the “second engaging portion” of the present invention.
The spring receiving member 150 is an example of a configuration corresponding to the “driven member” of the present invention.
The coil spring 155 is an example of a configuration corresponding to the “biasing member” 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 stopper 170 is an example of a configuration corresponding to the “rotation restricting portion” of the present invention.
The forward position is an example of a configuration corresponding to the “third position” of the present invention.
The rear second position is an example of a configuration corresponding to the “first position” of the present invention.
The rear third position is an example of a configuration corresponding to the “second position” of the present invention.

DESCRIPTION OF SYMBOLS 100 Screw driver 101 Main body part 103 Main housing 103a Partition wall 104 Front housing 104a Concave part 105 Locator 107 Handle 107a Trigger 107b Changeover switch 109 Power cable 110 Motor 111 Output shaft 111a Bearing 112 Gear tooth 119 Tool bit 120 Drive mechanism 121 Needle bearing 122 Front side Bearing 123 Bearing 125 Drive gear 126 Bottom wall 127 Side wall 128 Gear teeth 130 Retainer 131 Base 131A Contact portion 131a Engagement hole 131b Engagement hole 131b1 First region 131b2 Second region 131b3 Third region 132 First side wall 133 Second side wall 133a Inclined part 134 Roller holding part 138 Engaging pin 139 Engaging ball 140 Roller 145 Lock sleeve 146 Roller engaging part 47 Retainer engagement portion 147a Inclined portion 150 Spring receiving member 150a Engagement hole 151 Roller engagement portion 152 Ball contact portion 153 Ball 155 Coil spring 160 Spindle 161 Front side shaft portion 162 Rear side shaft portion 162a Groove portion 162b Ball engagement portion 163 Hollow Portion 164 Communication hole 165 Rear end bearing 166 Engagement portion 167 Non-engagement portion 170 Stopper 170A Through hole 171 Planar region 172 Curved region 181 Oil seal

Claims (7)

A work tool that performs a predetermined work by rotating the tip tool removably held in the tip region of the tool body around the long axis of the tip tool,
A motor,
While holding the tip tool, with respect to the long axis direction of the tip tool, a foremost position, a first position spaced rearward from the foremost position, and a second position spaced rearward from the first position A tip tool holder that is movable between positions ;
A rotation drive mechanism that transmits the rotation of the motor to the tip tool holding portion and rotationally drives the tip tool held by the tip tool holding portion;
The rotational drive mechanism is
A drive member that is rotationally driven by the motor;
A driven member arranged coaxially with the drive member and connected to the tip tool holding portion;
A clamping position provided between the driving member and the driven member and sandwiched between the driving member and the driven member and a clamping position where the driving member and the driven member cannot be clamped about the rotation axis of the driving member. It is movable between the impossible positions, and is configured to transmit the rotation of the driving member to the driven member by being held between the driving member and the driven member at the holding position, and at the non-holdable position, A transmission member configured to block transmission of rotation of the drive member to the driven member,
In the state where the tip tool holding portion is located at the foremost position, the transmission member is placed at the non-clamping position, so that the rotational driving force of the tip tool holding portion in a predetermined forward direction and a reverse direction can be reduced. Configured to block transmission,
In a state where the tip tool holding portion is positioned at the first position, the transmission member is sandwiched the driven member and the drive member in the clamping position, the tip tool holder is rotated in a predetermined direction opposite Configured to
In the state where the tip tool holding portion is located at the second position, the transmission member is held between the driving member and the driven member at the holding position, and the tip tool holding portion is in a forward direction opposite to the reverse direction. It is comprised so that it may be rotationally driven by, and the work tool characterized by the above-mentioned. The work tool according to claim 1 ,
An urging member for urging the tip tool holding portion toward the foremost position with respect to the longitudinal direction of the tip tool ;
The rotational drive mechanism is moved together with the tip tool holding portion when the tip tool holding portion is moved away from the foremost position against the urging force of the urging member, and the transmission is transmitted. A work tool comprising a switching member that switches a member from the non-clamping position to the clamping position. The work tool according to claim 2 ,
The rotational drive mechanism includes a retainer that holds the transmission member,
The retainer is formed with a first engagement portion,
The switching member is formed with a second engagement portion engageable with the first engagement portion,
At least one engaging portion of the first engaging portion and the second engaging portion is constituted by a lead surface,
When the tip tool holding portion is moved away from the foremost position in the longitudinal direction of the tip tool by pressing the tip tool held by the tip tool holding portion against the workpiece. In addition, the retainer is moved relative to the switching member around the long axis of the tip tool by the engagement of the first engagement portion and the second engagement portion, and the transmission member cannot be clamped. Configured to be moved from a position to the clamping position;
When the pressing of the tip tool against the workpiece is released, the retainer moves around the major axis of the tip tool with respect to the switching member by the engagement of the first engagement portion and the second engagement portion. The work tool is configured such that the transmission member is moved from the clamping position to the non-clamping position. The work tool according to any one of claims 1 to 4,
A rotation restricting portion that is attached to the tool main body and engages with the tip tool holding portion located at the foremost position to restrict both the forward and reverse rotations of the tip tool holding portion; A featured work tool. The work tool according to claim 4 ,
The tip tool holding portion includes an outer surface around a rotation axis of the tip tool holding portion,
The rotation restricting portion includes an inner surface that engages with the outer peripheral surface. The work tool according to claim 5 ,
A work tool characterized in that a cross-sectional shape of the inner surface of the rotation restricting portion orthogonal to a rotation axis of the tip tool holding portion is set as a non-circular cross-sectional shape. The work tool according to any one of claims 1 to 6 ,
The drive member is formed in a cylindrical shape,
The rotational drive mechanism is disposed coaxially with the drive member in the cylindrical internal space of the drive member, and retainer that holds the transmission member;
A bearing having an outer ring region inscribed in the drive member,
The retainer is connected to the outer ring region and configured to be rotatable by the drive member.

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