JP4746958B2 - Work tools - Google Patents

Description

  The present invention relates to a work tool such as a disk grinder that performs a machining operation using the rotational motion of a tip tool.

Japanese Patent Application Laid-Open No. 11-72122 (Patent Document 1) discloses a hand-held electric screw tightening tool provided with a spindle lock mechanism for facilitating tool replacement. In this screw tightening tool, a drive shaft as a drive side rotation member and a spindle as a driven side rotation member are connected via a shaft coupling. In the shaft coupling, when a rotational force is input from the drive shaft side, the claw portion of the drive side shaft joint abuts on the claw portion of the driven side shaft joint in the circumferential direction, and thereby the rotational force of the drive shaft is applied to the spindle. However, when a rotational force (external force) is input from the spindle side, the lock member is engaged between the driven side shaft joint and the lock ring fixed to the housing, thereby fixing the rotation of the driven shaft. This is a configuration. According to the electric screw tightening tool including the spindle lock mechanism having such a configuration, it is not necessary to bother to lock the rotation of the spindle when changing the tool, and the tool can be changed easily.
In the case of the spindle lock mechanism of the above type, there is a gap between the position where the claw portion of the drive side shaft joint and the claw portion of the driven side shaft joint abut each other and the position where the lock member is engaged between the driven side shaft joint and the lock ring. A predetermined play is required in the circumferential direction. For this reason, during the rotational driving of the spindle, the rotation of the spindle becomes faster or slower than the rotation of the drive shaft due to a change (increase / decrease) in the rotational load on the driven side. In other words, relative rotation occurs between the spindle and the drive shaft as a result of the above play, and as a result, the separation operation and the contact operation are repeated between the claw portion of the drive side shaft joint and the claw portion of the driven side shaft joint. Vibration or abnormal noise will occur. In view of this, in Patent Document 1, the relative rotation of both shaft joints (preceding rotation of the driven-side rotating member) is suppressed between the drive-side shaft joint and the driven-side shaft joint, and the integral rotation of both shaft-joints is maintained. A friction member is provided.

In the case of Patent Document 1, the integral rotation of both shaft joints is maintained by a friction member interposed between both shaft joints, and when an external force exceeding the frictional force by the friction member acts between both shaft joints, The maintenance of rotation is released. In other words, there is still room for improvement in terms of variation in operation.
JP 11-72122 A

  The present invention has been made in view of the above points, and in a work tool having a rotary tip tool, the driving-side rotating member and the driven-side rotating member are integrated via a contact surface extending in the radial direction. It aims at providing the technique which can maintain rotation reliably.

In order to achieve the above object, the invention described in each claim is configured.
According to the first aspect of the present invention, the driving side rotating member disposed on the work tool main body, the driven side rotating member disposed on the work tool main body and rotatable coaxially with the driving rotating member, A power receiving portion provided in a protruding shape in the radial direction on the driven-side rotating member, and the drive-side rotating member rotate together to contact the power receiving portion and transmit the rotational force of the driving-side rotating member to the driven-side rotating member. And a tip tool that performs a predetermined machining operation by being rotationally driven through the driven side rotation member. The “work tool” in the present invention typically corresponds to a disk grinder that performs a grinding work or a polishing work on a workpiece by rotating a grindstone as a tip tool, but is not limited to a disk grinder, The present invention can be widely applied to any work tool that performs a predetermined machining operation on a workpiece with a tip tool that performs a rotating operation.
The work tool of the present invention has a lock member. The lock member is provided in the work tool main body, and the driving side rotating member is driven to rotate. Accordingly, the driven side rotating member rotates integrally with the driving side rotating member through a contact state between the power transmission unit and the power receiving unit. When this is done, the rotation of the driven-side rotating member is allowed to allow the tip tool to perform a predetermined machining operation, and a rotational force by manual operation is input to the driven-side rotating member in order to replace the tip tool. When the member rotates relative to the driving side rotating member, the rotation of the driven side rotating member is locked. In other words, the lock member locks the rotation of the driven-side rotating member when an external force in the relative rotational direction with respect to the driven-side rotating member is applied to the driven-side rotating member during the tip tool replacement operation. This makes it possible to perform attachment and removal work of the tip tool.

The work tool according to the present invention has a characteristic configuration in which it is interposed between the driving side rotating member and the driven side rotating member, and an outer side position and an inner side position in the radial direction of the driving side rotating member. An actuating member moving between the two. The “actuating member” in the present invention typically corresponds to a sphere, but does not hinder the application of a cylindrical body, a spindle shape, or the like. When the driving side rotating member is driven to rotate, the actuating member is placed at the outer side position by the centrifugal force when rotating together with the driving side rotating member, and thereby the contact between the power transmission unit and the power receiving unit is established. It is set as the structure which maintains the integral rotation state of this drive side rotation member and the driven side rotation member. This reliably prevents the driven-side rotating member from rotating faster than the driving-side rotating member (preceding rotation of the driven-side rotating member relative to the driving-side rotating member) due to a change (increase / decrease) in the rotational load of the driven-side rotating member. As a result, it is possible to reliably prevent the occurrence of vibrations or abnormal noises due to repeated separation and contact operations between the power transmission unit and the power receiving unit.
In addition, when the tip tool is replaced, the operating member moves from the outer side position to the inner side position, and releases the contact state between the power transmission unit and the power receiving unit with respect to the driven side rotation member. Allowing the driven-side rotating member to rotate relative to the driving-side rotating member in the direction in which the contact state between the power transmission unit and the power receiving unit is released based on the input of the rotational force by manual operation of Thus, the lock member locks the rotation of the driven side rotation member. That is, in a state where the operating member is placed in the inward position, the rotation of the driven side rotation member is locked by the lock member, and the attachment and removal work of the tip tool can be easily performed.

(Invention of Claim 2)
According to the second aspect of the present invention, in the work tool according to the first aspect, any one of the axial end surface of the driving side rotating member and the axial end surface of the driven side rotating member, which are arranged to face each other. One is provided with a first guide groove extending in the radial direction, and one of the other is provided with a second guide groove extending in the radial direction while intersecting the first guide groove. The actuating member is constituted by a sphere, and the radially outer end portions of the first guide groove and the second guide groove are fitted in the first guide groove and the second guide groove. And the inner side end. The first guide groove and the second guide groove are arranged such that when the driving side rotating member and the driven side rotating member rotate integrally through the contact state between the power transmission unit and the power receiving unit, And is engaged with the radial wall surfaces of the first guide groove and the second guide groove so that the drive-side rotating member and the driven member are driven. The relative rotation of the side rotation member is set to be restricted. The first guide groove and the second guide groove are formed when the driven side rotating member is rotated relative to the driving side rotating member by a manual operation in a direction separating the power receiving unit from the power transmitting unit. By pressing the sphere with the radial wall surface of the guide groove or the second guide groove, the sphere is moved inward of the first guide groove and the second guide groove. In the present invention, “extending in the radial direction in an intersecting state” means that either one of the guide grooves is formed in parallel to the radial straight line passing through the rotation axis of the drive side rotation member, and the other guide groove Both of the embodiments in which both guide grooves intersect with each other by being formed in an inclined shape or the embodiments in which both guide grooves intersect with each other when both guide grooves are formed in an inclined shape are suitably included.
According to the present invention, a sphere is fitted into the first and second guide grooves arranged in an intersecting manner, and the sphere is held at the outer side end of the guide groove, whereby the power transmission unit and the power receiving unit are connected. Maintains the integral rotation of the drive-side rotating member and the driven-side rotating member through the contact state, and allows the relative rotation between the driving-side rotating member and the driven-side rotating member using the radial movement of the sphere. It is the structure to do. Thereby, operational stability and certainty are obtained.

(Invention of Claim 3)
According to a third aspect of the present invention, in the work tool according to the second aspect, of the first and second guide grooves, at least the guide groove far from the tip tool is inward from the outer end. When the work tool body is turned in the opposite direction so that the tip tool faces upward when the drive-side rotating member is stopped, the sphere is farther under its own weight. It was set as the structure which moves to the inward side from the outer side along the inclined surface of this guide groove. For example, when the work tool is a disc grinder used for grinding work or polishing work, the grindstone as the tip tool is exchanged with the disc grinder inverted so that the grinding surface of the grindstone faces upward. Therefore, when the work tool main body is inverted as in the present invention, the sphere is easily moved by its own weight along the downwardly inclined surface facing inward, and when a rotational force by manual operation is applied to the driven side rotating member The actuating member easily moves inward, and it becomes possible to easily obtain the rotation lock by the lock member of the driven side rotating member.

(Invention of Claim 4)
According to a fourth aspect of the present invention, in the work tool according to the third aspect, the outer end portions of the first and second guide grooves have a radial direction passing through the rotation axis of the drive side rotation member. In a state where a parallel region parallel to the straight line is set, and the driving-side rotating member and the driven-side rotating member are integrally rotated through a contact state between the power transmission unit and the power receiving unit, the first or second The wall surface of the guide groove in the radial direction is in contact with the sphere at a substantially right angle.
According to this invention, the 1st and 2nd guide groove is set as the structure which has a parallel area | region parallel to the radial straight line which passes along the rotating shaft line of a drive side rotation member in an outer side edge part. For example, when the entire guide groove is set to be inclined in the radial direction, the radial wall surface (inclined surface) of the first or second guide groove with respect to the sphere when the drive side rotation member is rotationally driven. There is a possibility that a force in the direction of moving the sphere inwardly acts through the via. This force is a force that opposes the centrifugal force acting on the operating member, and is not preferable. According to the present invention, in a state where the driving side rotating member and the driven side rotating member are integrally rotated through the contact state between the power transmission unit and the power receiving unit, the sphere is placed in a parallel region of the guide groove, The radial wall surface of the guide groove is in contact with the sphere at a substantially right angle. As a result, the force acting on the sphere from the radial wall surface of the first or second guide groove is directed toward the center of the sphere. That is, it is difficult for the force to move the sphere inward, thereby causing the sphere to move outwardly of the first and second guide grooves, that is, the driving side rotating member and the driven side rotating member. It is possible to further enhance the effect of holding the outer rotational position maintaining the integral rotation state.

  According to the present invention, in a work tool provided with a rotary tip tool, it is possible to reliably maintain the integral rotation of the driving side rotating member and the driven side rotating member via the contact surfaces extending in the radial direction. Technology was provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. In the present embodiment, as an example of a work tool, a description will be given using a hand-held electric disc grinder used for grinding work or grinding work of various work materials such as metal, concrete, and stone. FIG. 1 is a longitudinal sectional view showing the entire configuration of the electric disc grinder 101. For the sake of convenience, a part of the rear side (right side in the figure) of the disc grinder 101 is omitted in FIG. FIG. 2 is a longitudinal sectional view showing the power transmission mechanism. FIG. 3 is a diagram showing a cross-sectional structure of the power transmission mechanism, and the cross-sectional structures based on the cross-section indicating lines (AA line and BB line) in FIG. 2 are shown in the upper and lower stages, respectively, and from the left side to the right side. The operation modes of the respective cross-sectional structure portions are sequentially shown, wherein (I) indicates a processing operation, (II) indicates the removal of the grindstone, and (III) indicates the mounting of the grindstone. FIGS. 4 to 14 are component diagrams showing components of the power transmission mechanism, FIGS. 4 to 6 show gears, FIGS. 7 and 8 show spindles, and FIGS. 9 and 10 show lock cams. 11 and 12 show a lock ring, and FIGS. 13 and 14 show a retainer.

  As shown in FIG. 1, the electric disc grinder 101 has a major axis direction as a front-rear direction (left-right direction in the figure), and an outer body is constituted by a main body portion 103 including a motor housing 105 and a gear housing 107. . The main body 103 corresponds to the “work tool main body” in the present invention. The motor housing 105 is formed in a substantially cylindrical shape, and a drive motor 111 is accommodated in the motor housing 105. The drive motor 111 is arranged such that the rotation axis direction of the rotor 113 is the long axis direction of the electric disc grinder 101. A small bevel gear 117 is attached to the front end side (left side in the figure) of the motor shaft 115 of the drive motor 111, and a cooling fan 119 is attached so as to rotate integrally with the motor shaft 115. In the present embodiment, the rotation direction of the drive motor 111 is set to one direction.

  A power transmission mechanism 109 for transmitting the rotational output of the drive motor 111 to the grindstone 141 is accommodated in the gear housing 107 connected to the front end portion of the motor housing 105. The grindstone 141 corresponds to the “tip tool” in the present invention. As shown in FIG. 2, the power transmission mechanism 109 includes a small bevel gear 117 (see FIG. 1), a gear 121, a spindle 123, and a lock cam 151. The gear 121 corresponds to the “driving side rotating member” in the present invention, and the spindle 123 corresponds to the “driven side rotating member” in the present invention. It is assumed that the gear 121 driven by the drive motor 111 is rotated in the arrow direction (right rotation) shown in FIG.

  The gear 121 has teeth that are always meshed and engaged with the small bevel gear 117 (see FIG. 1) in the outer peripheral region, and is arranged so that the axial direction thereof is a direction perpendicular to the rotation axis of the drive motor 111, that is, the vertical direction. Is done. The spindle 123 is concentrically disposed through the shaft hole of the gear 121 and is fitted to the gear 121 so as to be relatively rotatable. The spindle 123 extends vertically and has a double-supported support structure that is rotatably supported by the gear housing 107 via bearings 125 and 126 (see FIG. 1) at the upper and lower portions thereof.

  As shown in FIG. 1, the tip (lower end) of the spindle 123 protrudes from the lower surface of the gear housing 107, and a grindstone mounting portion 131 having a two-surface width and a threaded portion is formed at the protruding end portion. The grindstone 141 is detachably mounted on the grindstone mounting portion 131 so as to be sandwiched from above and below via the mounting flanges 133 and 135 on the inner side (the upper surface of the grindstone) and the outer side (the lower surface of the grindstone). The inner mounting flange 133 located on the upper surface side of the grindstone 141 is attached to the grindstone mounting portion 131 through a two-surface width so as not to be relatively rotatable, and the outer mounting flange 135 located on the lower surface side is screwed into the screw portion. In this structure, the grindstone 141 is attached. The outer mounting flange 135 is a member having a screw hole, and is set so that the direction opposite to the rotation direction of the spindle 123 is the tightening direction. That is, it is set so as to be tightened when the grindstone 141 is driven to rotate. The rear half of the grindstone 141 is covered with a cover 143.

  As shown in FIGS. 9 and 10, the lock cam 151 is formed in a substantially cylindrical shape having a spline hole 151 a and is arranged concentrically with the gear 121 on the lower surface side which is one end portion of the gear 121 in the axial direction. Yes. The lock cam 151 is connected to a spline shaft portion 123 a formed on the spindle 123 by spline fitting, thereby rotating integrally with the spindle 123. As shown in FIG. 2, the gear 121 and the lock cam 151 are restricted from moving in the axial direction with respect to the spindle 123 by a lower bearing 126 and a washer 159 attached to the spindle 123 via a circlip 157. . The lock cam 151 has two claw portions 153 having a phase difference of 180 degrees in the circumferential direction on the outer peripheral surface thereof, and a phase difference of 90 degrees in the circumferential direction with respect to the claw portions 153 (therefore, each other). Two concave cam portions 155 having a circular arc cross section (having a phase difference of 180 degrees) are provided. The claw portion 153 is provided so as to protrude in a radial direction with a predetermined length, and the two concave cam portions 155 are formed in parallel to each other. The claw portion 153 of the lock cam 151 is provided to receive rotational force from the two claw portions 121a (see FIGS. 5 and 6) for power transmission provided on the gear 121 and transmit it to the spindle 123. A configuration for transmitting the rotational force will be described later.

  As shown in FIGS. 1, 2, and 3, a circular lock ring 161 is disposed between the gear 121 and the lower bearing 126 and on the outer periphery of the lock cam 151. As shown in FIGS. 11 and 12, the lock ring 161 has a plurality of projections 161a projecting radially on the outer periphery, and the projections 161a are formed on the inner wall surface of the gear housing 107 corresponding to the projections 161a. The movement in the circumferential direction is restricted by being engaged with the recessed portion 107a (see FIG. 1). The lock ring 161 has an inner peripheral surface having an inner diameter slightly larger than the outer diameter of the region including the claw portion 153 of the lock cam 151. The inner peripheral surface of the lock ring 161 is a concave inner peripheral surface 161b having a concave surface with an arc-shaped cross section over the entire periphery, and a predetermined gap 156 between the outer peripheral surface of the lock cam 151 and the concave cam portion 155. Is formed (see FIG. 3).

  As shown in FIG. 3, a first steel ball (steel ball) 165 is disposed in the gap 156 between the concave inner peripheral surface 161 b of the lock ring 161 and the concave cam portion 155 of the lock cam 151. The first steel ball 165 corresponds to a “lock member” in the present invention. The radial interval of the gap 156 formed by the concave cam portion 155 of the lock cam 151 and the concave inner peripheral surface 161b of the lock ring 161 is maximum at the circumferential center of the concave cam portion 155 and minimum at the end. The outer diameter of the first steel balls 165 is set to be smaller than the maximum interval of the gap 156 and larger than the minimum interval portion. For this reason, the first steel ball 165 allows rotation of the spindle 123 in a state where the first steel ball 165 is positioned at the maximum interval portion of the gap 156 (the state shown in FIG. 3I), but the play area ( In the state of moving through the movable region (the state shown in (II) and (III) of FIG. 3), the concave cam portion 155 of the lock cam 151 and the concave inner peripheral surface 161b of the lock ring 161 are engaged, thereby the lock cam 151 and the lock ring 161 are locked, and the rotation of the spindle 123 is locked. That is, the lock cam 151, the lock ring 161, and the first steel ball 165 constitute a spindle lock mechanism.

  On the lower surface side of the gear 121, four claw portions 121a and 121b (see FIG. 5) having a phase difference of 90 degrees from each other around the axis of the gear 121 are provided. Each claw portion 121a, 121b is formed in a cross-sectional arc shape extending in a predetermined length in the axial direction and the circumferential direction of the gear 121, and as shown in FIG. 3, the claw portion 153 of the lock cam 151 and the concave cam portion 155. Between the outer peripheral surface of the lock cam 151 and the concave inner peripheral surface 161b of the lock ring 161. Of the four claw portions 121a and 121b on the gear 121 side, one end portion (front side in the rotational direction) of the two claw portions 121a facing each other across the axis is the circumference of the claw portion 153 of the lock cam 151. Abutting on one end of the direction, a rotational force in the direction of the arrow (clockwise) is applied to the lock cam 151 to rotate the spindle 123 in the same direction. That is, the claw portion 121a of the gear 121 and the claw portion 153 of the lock cam 151 constitute a rotational force transmission mechanism that transmits the rotational force of the gear 121 to the spindle 123. Of the claw portions 121a and 121b of the gear 121, the two claw portions 121a contacting the claw portion 153 of the lock cam 151 correspond to the “power transmission portion” in the present invention, and the lock cam 151 and the claw portion 153 are the present invention. This corresponds to the “power receiving part”.

  As described above, in the integrally rotating state in which the gear 121 and the spindle 123 rotate through the contact state between the claw portion 121a on the gear 121 side and the claw portion 153 on the lock cam 151 side, the other two gears on the gear 121 side are used. One end of the claw portion 121b abuts on the first steel ball 165, holds the first steel ball 165 at the maximum gap portion of the gap 156, and avoids the engagement between the lock cam 151 and the lock ring 161. That is, the integral rotation of the spindle 123 with the gear 121 is allowed.

  As shown in FIG. 3, the claw portion 153 of the lock cam 151 has a predetermined gap (hereinafter referred to as play) in the circumferential direction with respect to the claw portions 121 a and 121 b of the gear 121 positioned with the claw portion 153 interposed therebetween. That is, the lock cam 151 is allowed to rotate relative to the gear 121 in the circumferential direction within the range of play. For this reason, during the rotational operation of the spindle 123, when the rotational load on the spindle side (driven side) changes (increases or decreases), and accordingly the rotation of the spindle 123 precedes or delays the rotation of the gear 121, the gear The separation operation and the contact operation are repeated between the claw portions 121a and 121b on the 121 side and the claw portion 153 on the lock cam 151 side, and accordingly, vibration or noise is generated. In order to avoid such a phenomenon and maintain the integral rotation of the spindle 123 and the gear 121, an integral rotation maintaining mechanism 181 for preventing the relative rotation of the gear 121 and the spindle 123 is provided.

  The integral rotation maintaining mechanism 181 is mainly composed of a retainer 183 and a second steel ball (steel ball) 185. The second steel ball 185 corresponds to the “actuating member” in the present invention. The retainer 183 is a plate-like member having a spline hole 183a (see FIGS. 13 and 14) formed in the center, and is disposed on the upper surface of the gear 121 so as to be relatively rotatable. They are connected (see FIGS. 1 and 2) by spline fitting. Further, as shown in FIGS. 1 and 2, the retainer 183 is restricted from moving in the axial direction by a washer 159 attached to the spindle 123 via a circlip 157.

  The second steel balls 185 are formed on the upper surface side of the gear 121 with two steel ball grooves 187 formed with a phase difference of 180 degrees in the circumferential direction and on the lower surface side of the retainer 183 with a phase difference of 180 degrees in the circumferential direction. The two steel ball grooves 188 are disposed so as to be respectively interposed. The steel ball grooves 187 and 188 correspond to “guide grooves” in the present invention. As shown in FIG. 3, the steel ball groove 187 of the gear 121 is formed to be inclined with respect to a straight line in the radial direction orthogonal to the axis of the gear 121, and on the outer side in the radial direction (the side away from the axis). ) Is formed with a parallel portion 187a that is parallel to a radial straight line orthogonal to the axis. The parallel portion 187a corresponds to a “parallel region” in the present invention. The inclination direction of the steel ball groove 187 of the gear 121 is inclined with respect to the rotation direction of the gear 121 so that the inner side is the front side and the outer side is the rear side. On the other hand, as shown in FIG. 14, the steel ball groove 188 of the retainer 183 is formed in parallel to a radial straight line perpendicular to the axis of the gear 121. The groove width of the steel ball grooves 178 and 188 is set equal to or slightly larger than the diameter of the second steel ball 185 so that the second steel ball 185 can smoothly roll.

  As shown in FIGS. 1 and 2, the second steel ball 185 is fitted in both the inclined steel ball groove 187 on the gear 121 side and the parallel steel ball groove 188 on the retainer 183 side. The steel ball grooves 187 and 188 are movable between the outer side end and the inner side end in the radial direction. In other words, the second steel ball 185 moves between the outer end and the inner end of the steel ball grooves 187 and 188 so that the gear 121 and the retainer 183 are allowed to move relative to each other. In other words, the relative movement of the gear 121 and the retainer 183 is disabled unless the second steel ball 185 moves. The steel ball groove 187 of the gear 121 and the steel ball groove 188 of the retainer 183 are formed so that the second steel ball 185 is in the radial direction when the claw portion 121a of the gear 121 contacts the claw portion 153 of the lock cam 151. The second steel ball 185 is set so as to be placed on the outer side end portion, and the claw portion 121a of the gear 121 is moved toward the inward side from the outer side end portion in the radial direction so that the claw portion 121a of the lock cam 151 It is allowed to leave the part 153. The outer end portions of the steel ball grooves 187 and 188 correspond to the “outer side position” in the present invention, and the inner end portions correspond to the “inner side position” in the present invention.

  Further, as shown in FIGS. 1 and 2, the upper surface of the steel ball groove 188 of the retainer 183 is an upward inclined surface from the outer side toward the inner side. That is, the steel ball groove 188 is inclined from the outer side to the inner side so that the inner side is away from the grindstone 141.

  The electric disc grinder 101 according to the present embodiment is configured as described above. Next, the operation and usage will be described. When the motor shaft 115, the small bevel gear 117, and the gear 121 are rotated by energization driving of the drive motor 111, the two claw portions 121a of the gear 121 are connected to the lock cam 151 as shown in the lower side of FIG. Abutting on the claw portion 153, a rightward rotational force is applied to the lock cam 151, and the spindle 123 is rotated to the right. Further, the other two claw portions 121b of the gear 121 are simultaneously brought into contact with the first steel ball 165, and the first steel ball 165 is separated from the concave cam portion 155 of the lock cam 151 and the gap 156 between the concave inner peripheral surface 161b of the lock ring 161. It is held at the maximum spacing part and rotated together. For this reason, the first steel ball 165 does not bite between the lock cam 151 and the lock ring 161.

  As described above, the steel ball groove 178 of the gear 121 and the steel ball groove 188 of the retainer 183 are formed so that the second steel ball 185 is in the radial direction when the claw portion 121a of the gear 121 contacts the claw portion 153 of the lock cam 151. It is set so that it may be placed at the outer end of the. For this reason, in a state where the gear 121 is rotationally driven, the second steel ball 185 is placed at the outer end of the steel ball grooves 187 and 188 as shown on the upper side of FIG. Since a centrifugal force acts on the second steel ball 185 that rotates together with the gear 121, the second steel ball 185 is held at the outer end by this centrifugal force. That is, the second steel ball 18 is engaged with the radial side wall of the steel ball groove 187 of the gear 121 and the radial side wall of the steel ball groove 188 of the retainer 183, respectively. Restrict movement. Thereby, the contact state of the claw part 121a of the gear 121 and the claw part 153 of the lock cam 151 is maintained. For this reason, the preceding rotation with respect to the gear 121 of the spindle 123 based on the change of the rotational load on the driven side is prevented, and the integral rotation of the spindle 123 and the gear 121 is maintained. As a result, the occurrence of the phenomenon that the separation operation and the contact operation are repeated between the claw portions 121a and 121b of the gear 121 and the claw portion 153 of the lock cam 151 is avoided.

  Next, the case where the grindstone 141 is removed from the spindle 123 will be described. In addition, as shown in FIG. 15, the replacement | exchange operation | work of the grindstone 141 is generally performed by making the direction of the main-body part 103 reverse so that the grindstone 141 may face upwards, ie, the state inverted. When reversed in this way, the upper surface of the steel ball groove 188 of the retainer 183 (becomes a bottom surface with the reversal) becomes a downward inclined surface from the outer side end to the inner side end. In addition, when the grindstone 141 is in a rotation stopped state, no centrifugal force acts on the second steel ball 185. For this reason, the second steel ball 185 is placed in a state where the second steel ball 185 is easily moved from the outer side end portion toward the inner side end portion by its own weight in the steel ball grooves 187 and 188. In this state, when the grindstone 141 is grasped by hand and rotated intermittently, the second steel ball 185 is pushed by the retainer 183 connected in the circumferential direction via the grindstone 141, the spindle 123, and the spline. The steel ball 185 moves inward by its own weight along the inclined surface of the steel ball groove 188 of the retainer 183 (see the upper part of (II) in FIG. 3).

  This inward movement of the second steel ball 185 cancels the relative movement restriction of the gear 121 and the retainer 183 by the second steel ball 185, and the relative rotation of the retainer 183 with respect to the gear 121 is allowed. When the spindle 123 is rotated together with the retainer 183 in this state, the lock cam 151 connected to the spindle 123 via the spline is rotated, and the claw portion 153 of the lock cam 151 is separated from the claw portion 121a of the gear 121. That is, the lock cam 151 rotates relative to the gear 121 clockwise. By this relative rotation, the first steel ball 165 moves away from the claw portion 121b of the gear 121 and moves in the movable region, so that the first steel ball 165 moves between the concave cam portion 155 of the lock cam 151 and the concave inner peripheral surface 161b of the lock ring 161. As a result, the first steel ball 165 is bitten and the rotation of the spindle 123 is locked (see the lower part of (II) in FIG. 3). Thereafter, by rotating the mounting flange 135 clockwise relative to the rotation-locked spindle 123, the mounting flange 135 can be removed from the grindstone mounting portion 131 of the spindle 123, and the grindstone 141 can be removed.

  Next, the case where the grindstone 141 is attached to the spindle 123 will be described. The grindstone 141 is attached by fitting the grindstone 141 into the grindstone mounting portion 131 and rotating and tightening the attachment flange 135 counterclockwise. During this counterclockwise rotation, as shown in the lower part of FIG. 3 (III), when the lock cam 151 is rotated together with the spindle 123, even if the gear 121 is rotated in the same direction following the rotation, One steel ball 165 is not pushed. Therefore, the first steel ball 165 is engaged between the concave cam portion 155 and the concave inner peripheral surface 161 b of the lock ring 161. That is, the counterclockwise rotation of the spindle 123 causes the rotation lock of the spindle 123 by the first steel ball 165 to work regardless of the positional relationship between the gear 121 and the spindle 123. As a result, the grindstone 141 can be tightened, and the grindstone 141 can be attached to the spindle 123.

  As described above, according to the present embodiment, when the grindstone 141 is detached from the spindle 123 or attached, when a rotational force (external force) is input from the spindle 123 side, the lock cam 151, the lock ring 161, and the first A spindle lock mechanism constituted by one steel ball 165 operates. That is, the rotation of the spindle 123 can be fixed without fixing the spindle 123 from the outside. For this reason, the operability of attaching / detaching the grindstone 141 can be improved.

  The integral rotation maintaining mechanism 181 for maintaining the integral rotation of the gear 121 and the spindle 123 according to the present embodiment is such that the gear 121 and the spindle 123 are connected to the claw portion 121a of the gear 121 and the lock cam when the grindstone 141 is rotationally driven. The second steel ball 185 disposed between the steel ball groove 187 of the gear 121 and the steel ball groove 188 of the retainer 183 when rotating integrally through contact with the claw portion 153 of the 151 includes the steel ball. The grooves 187 and 188 are placed at the outer ends, and the second steel balls 185 are held at the outer ends by the centrifugal force acting on the second steel balls 185. Therefore, it is possible to reliably prevent the preceding rotation of the spindle 123 with respect to the gear 121 regardless of fluctuations in the rotational load on the driven side. As a result, it is possible to prevent the occurrence of vibrations or abnormal noises caused by repeated contact and separation between the claw portions 121a and 121b of the gear 121 and the claw portion 153 of the lock cam 151.

  In the present embodiment, the steel ball groove 187 of the gear 121 has a parallel part 187a at the outer side end. In a state where the gear 121 and the spindle 123 are integrally rotated through a contact state between the claw portion 121 a of the gear 121 and the claw portion 153 of the lock cam 151, the second steel ball 185 is in the steel ball groove 187 of the gear 121. It is placed on the parallel part 187a. Further, the steel ball groove 188 in the retainer 183 is a groove parallel to the radial direction. For this reason, the force acting on the second steel ball 185 via the radial wall surfaces of the steel ball grooves 187 and 188 is generally directed toward the center of the second steel ball 185. That is, it is difficult for a force to act on the second steel ball 185 in the direction in which the second steel ball 185 is moved inward. As a result, the second steel ball 185 can be reliably held at the outer ends of the steel ball grooves 187 and 188, and as a result, the effect of maintaining the rotation of the gear 121 and the spindle 123 integrally can be further ensured.

Further, according to the present embodiment, the spindle 123 penetrates the gear 121, and the both ends of the spindle 123 are supported by the bearings 125 and 126, so-called both-end support structure. For this reason, the transmission of the rotational force between the gear 121 and the spindle 123 can be performed in a stable state. The spindle 123 is configured to support the gear 121 so as to be relatively rotatable in a state where the spindle 123 penetrates the gear 121. For this reason, the so-called centering between the spindle 123 and the gear 121 is performed by the fitting of the spindle 123 and the gear 121. As a result, when the spindle 123 is assembled to the gear housing 107, the centering is performed. There is no need to think about it. For this reason, assembly property improves.
Further, by adopting a configuration in which both ends of the spindle 123 are supported, the transmission of rotational force is stabilized and the force applied to the gear 121 and the spindle 123 is equalized. Therefore, the claw portion 121a of the gear 121 and the claw portion of the lock cam 151 are provided. It is possible to improve the service life of components related to transmission of rotational force such as 153 or the first steel ball 165.

  Further, since the spindle 123 is configured to penetrate the gear 121, when setting the integral rotation maintaining mechanism 181 between the gear 121 and the spindle 123, the setting position of the integral rotation maintaining mechanism 181 is set to the axis of the spindle 123. It can be set at any position in the direction. That is, according to the present embodiment, the integral rotation maintaining mechanism 181 is different from the gear lower surface side region where the mechanism for transmitting the rotational force of the gear 121 to the spindle 123 and the lock mechanism for locking the rotation of the spindle 123 are set. It can arrange | position using the area | region of the gear upper surface side. As a result, it is not necessary to assemble a plurality of types of mechanisms in a limited space, which is effective in improving the overall assemblability. In the present embodiment, in the electric disk grinder 101, the integral rotation maintaining mechanism 181 is arranged by effectively using the empty area on the gear upper surface side that originally exists as a dead space, and the size of the product is increased. Without this, the integral rotation maintaining mechanism 181 can be set.

  Further, in the integral rotation maintaining mechanism 181 according to the present embodiment, the second steel ball 185 is fitted into the steel ball grooves 187 and 188 provided in the gear 121 and the retainer 183 in the radial direction, and the radial direction of the steel ball grooves 187 and 188 is determined. In this configuration, the gear 121 and the spindle 123 are maintained in an integral rotation by the engagement of the wall surface of the first steel ball 185 and the second steel ball 185. That is, since the configuration is such that the direction orthogonal to the axial direction of the gear 121 is the engaging surface, the axial length of the integral rotation maintaining mechanism 181 is shortened compared to the configuration in which the axial direction of the gear 121 is the engaging surface. It is effective in planning.

In the present embodiment, the integrated rotation maintaining mechanism 181 is configured to be disposed on the upper surface side of the gear 121, but is configured to be disposed on the lower surface side of the gear 121, that is, a mechanism that transmits the rotational force of the gear 121 to the spindle 123. Further, the configuration may be changed such that the integral rotation maintaining mechanism 181 is disposed in a region where the lock mechanism for locking the rotation of the spindle 123 is disposed. The first steel balls 165 may be cylindrical (rollers).
Moreover, although this Embodiment demonstrated in the case of the electric disc grinder 101 used for a grinding operation | work or a grinding | polishing operation | work as an example of a working tool, it is not restricted to this, For example, like a screw-fastening tool, it is a tip tool. The present invention can be applied to any work tool that performs a predetermined machining operation by a rotating operation.

In view of the gist of the invention, the following aspects can be configured.
(Aspect 1)
"A work tool according to any one of claims 1 to 4,
The working tool, wherein the driven side rotating member is disposed in a state of penetrating a rotation axis of the driving side rotating member. "

  According to the first aspect of the invention, the driven-side rotating member penetrates the driving-side rotating member. Therefore, when the operating member is provided between the driving-side rotating member and the driven-side rotating member, The arrangement position can be set to an arbitrary position in the axial direction of the driving side rotating member and the driven side rotating member. That is, according to the present invention, a degree of freedom can be obtained with respect to the arrangement position of the actuating member. Further, since the driven-side rotating member passes through the driving-side rotating member, the shafts can be aligned with each other by fitting the both rotating members. As a result, when assembling to the housing, no centering is required, and the assemblability is improved. Furthermore, by adopting a configuration in which the driven-side rotating member penetrates the driving-side rotating member, it is possible to provide a so-called both-end supported structure in which the driven-side rotating member is supported by bearings on both sides in the axial direction. And if it is the support structure by both ends, the rotational force transmission between a drive side rotation member and a driven side rotation member can be performed in the stable state between bearings.

(Aspect 2)
“A work tool according to aspect 1,
The power transmission unit and the power receiving unit are arranged on one end side in the axial direction of the driving side rotating member, and the operating member is arranged on the other end side in the axial direction of the driving side rotating member. Work tool to do. "

  According to the second aspect of the present invention, the drive-side rotation via the arrangement region of the mechanism for transmitting the rotational force of the drive-side rotating member to the driven-side rotating member, and the contact state between the power transmitting unit and the power receiving unit. Since the arrangement region of the actuating member that maintains the integral rotation of the member and the driven-side rotating member can be set by using different end portions in the axial direction of the driving-side rotating member, each can be assembled using a wide space. This is possible and effective in improving assembly.

It is a longitudinal section showing the whole electric disc grinder composition concerning an embodiment of the present invention. It is an expanded sectional view of a power transmission mechanism part. It is sectional drawing of the rotational force transmission part based on the cross-section instruction | indication line (AA line, BB line) of FIG. When the grinding wheel is removed, (III) shows when the grinding wheel is attached. The retainer is indicated by a two-dot chain line. It is a top view of a gear. It is a bottom view of a gear. It is sectional drawing of a gear. It is a front view of a spindle. It is a half-section top view of a spindle. It is a top view of a lock cam. It is sectional drawing of a lock cam. It is a top view of a lock ring. It is sectional drawing of a lock ring. It is sectional drawing of a retainer. It is a top view of a retainer. It is the longitudinal cross-sectional view of the state which reversed the electric disc grinder so that a grindstone might become upward in the case of grindstone exchange.

Explanation of symbols

101 Electric disc grinder (work tool)
103 Main body (work tool main body)
105 Motor housing 107 Gear housing 107a Concave portion 109 Power transmission mechanism 111 Drive motor 113 Rotor 115 Motor shaft 117 Small bevel gear 119 Cooling fan 121 Gear (drive side rotating member)
121a Claw portion 121b Claw portion 121c Ball mounting recess 123 Spindle (driven rotation member)
123a Spline shaft portion 125 Bearing 126 Bearing 131 Wheel mounting portion 133 Inner mounting flange 135 Outer mounting flange 141 Wheel (tip tool)
143 Cover 151 Lock cam 151a Spline hole 153 Claw 155 Concave cam 157 Circlip 159 Washer 161 Lock ring 161a Protrusion 161b Concave inner peripheral surface 165 First steel ball (lock member)
181 Integrated rotation maintaining mechanism 183 Retainer 183a Spline hole 185 Second steel ball (actuating member)
187 Steel ball groove (guide groove)
188 Steel ball groove (guide groove)

Claims (4)

A drive-side rotating member disposed rotatably on the work tool body;
A driven-side rotating member disposed on the work tool main body and capable of rotating coaxially with the driving rotating member;
A power receiving portion provided in a protruding shape in the radial direction on the driven side rotating member;
A power transmission unit that rotates together with the drive side rotation member, contacts the power receiving unit, and transmits the rotational force of the drive side rotation member to the driven side rotation member;
A tip tool that performs a predetermined machining operation by being rotationally driven through the driven side rotation member;
Provided in the work tool main body, the drive-side rotating member is driven to rotate, and accordingly, the drive-side rotating member and the driven-side rotating member are brought into contact with each other via a contact state between the power transmission unit and the power receiving unit. When rotating integrally, the driven side rotating member is allowed to rotate so that the tip tool performs a predetermined processing operation, and a rotational force by manual operation is input to the driven side rotating member to replace the tip tool. Then, when the driven-side rotating member rotates relative to the driving-side rotating member, a lock member that locks the rotation of the driven-side rotating member;
An operating member interposed between the driving side rotating member and the driven side rotating member and moving between an outer side position and an inner side position in a radial direction of the driving side rotating member; Have
The actuating member is
When the driving side rotating member is driven to rotate, the driving side rotating member is placed at the outer side position by a centrifugal force when rotating together with the driving side rotating member, and thereby the contact between the power transmission unit and the power receiving unit is established. Maintaining an integral rotation state of all the drive side rotation members and the driven side rotation members;
When the tip tool is replaced, the tool moves from the outer side position to the inner side position, and releases the contact state between the power transmission unit and the power receiving unit with respect to the driven side rotation member. Based on the input of the rotational force by manual operation of the direction, the driven-side rotating member is relative to the driving-side rotating member in the direction in which the contact state between the power transmission unit and the power receiving unit is released. A work tool characterized by allowing rotation, whereby the lock member locks the rotation of the driven side rotation member. The work tool according to claim 1,
A first guide groove extending in the radial direction is provided on either one of the axial end surface of the driving-side rotating member and the axial end surface of the driven-side rotating member, which are arranged to face each other. On the other side, a second guide groove extending in the radial direction in a state of intersecting the first guide groove is provided,
The actuating member is constituted by a spherical body, and is radially outwardly connected to the first guide groove and the second guide groove in a state of being fitted into the first guide groove and the second guide groove. It is possible to move between the part and the inner side end,
The first guide groove and the second guide groove are formed when the driving-side rotating member and the driven-side rotating member rotate integrally through contact between the power transmission unit and the power receiving unit. Is placed at the outer ends of the first guide groove and the second guide groove, and engages with the radial wall surfaces of the first guide groove and the second guide groove, whereby the drive It is set so as to restrict the relative rotation of the side rotating member and the driven side rotating member, while the driven side rotating member is manually operated in a direction to separate the power receiving unit from the power transmitting unit with respect to the driving side rotating member. When the sphere is rotated by an operation, the sphere is pushed by the radial wall surface of the first guide groove or the second guide groove, thereby causing the sphere to move between the first guide groove and the second guide groove. Inward The power tool characterized by being configured to move to. The work tool according to claim 2,
Of the first and second guide grooves, at least one guide groove farther from the tip tool is inclined in a direction away from the tip tool from an outer side end to an inner side end, and the drive When the work tool main body is turned in the opposite direction so that the tip tool faces upward in the stopped state of the side rotating member, the sphere is under its own weight along the inclined surface of the one guide groove. A working tool characterized in that it is configured to move from the inside to the inside. The work tool according to claim 3,
A parallel region parallel to a radial straight line passing through the rotation axis of the drive side rotation member is set at the outer end portions of the first and second guide grooves, whereby the drive side rotation member and the In a state in which the driven-side rotating member is integrally rotated via the contact state between the power transmission unit and the power receiving unit, the radial wall surface of the first or second guide groove is against the sphere. A working tool characterized by having a configuration that makes contact at a substantially right angle.

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