EP2712708B1 - Impact rotation tool - Google Patents
Impact rotation tool Download PDFInfo
- Publication number
- EP2712708B1 EP2712708B1 EP13184680.0A EP13184680A EP2712708B1 EP 2712708 B1 EP2712708 B1 EP 2712708B1 EP 13184680 A EP13184680 A EP 13184680A EP 2712708 B1 EP2712708 B1 EP 2712708B1
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- EP
- European Patent Office
- Prior art keywords
- drive shaft
- coupling member
- anvil
- hole
- impact
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 230000008878 coupling Effects 0.000 claims description 132
- 238000010168 coupling process Methods 0.000 claims description 132
- 238000005859 coupling reaction Methods 0.000 claims description 132
- 230000007246 mechanism Effects 0.000 claims description 19
- 230000009467 reduction Effects 0.000 description 15
- 230000009471 action Effects 0.000 description 6
- 230000005540 biological transmission Effects 0.000 description 4
- 238000003780 insertion Methods 0.000 description 3
- 230000037431 insertion Effects 0.000 description 3
- 230000004323 axial length Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000005489 elastic deformation Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
- B25B21/00—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose
- B25B21/02—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose with means for imparting impact to screwdriver blade or nut socket
- B25B21/026—Impact clutches
Definitions
- the present invention relates to an impact rotation tool.
- An impact rotation tool includes a hammer coupled to a drive shaft, which is rotated and driven by a motor.
- the hammer impacts an anvil to generate an impact torque used by the impact rotation tool to tighten a screw.
- Japanese Patent No. 3911905 describes an impact rotation tool that is switched between an impact mode, in which the hammer impacts the anvil, and a drill mode, in which the anvil is rotated integrally with the drive shaft.
- the '905 patent describes an impact rotation tool 81 that includes an anvil 82, which is coaxial with and rotatable relative to a drive shaft 83.
- a hammer 84 which includes a hook 84a, is coupled to the drive shaft 83.
- the hook 84a is engaged with a portion of an arm 82a of the anvil 82.
- a hammer spring 85 urges the hammer 84 toward the anvil 82.
- the drive shaft 83 and the hammer 84 (anvil) rotate relative to each other.
- the drive shaft 83 includes a drive shaft hole 91 having a hexagonal cross-section.
- the drive shaft hole 91 faces the anvil 82 at a distal end of the drive shaft 83.
- the anvil 82 includes an anvil hole 92 having a hexagonal cross-section and facing toward the drive shaft 83.
- a hexagonal coupling member 93 is arranged in the drive shaft hole 91.
- the coupling member 93 is movable in the axial direction inside the drive shaft hole 91. Further, the coupling member 93 is engaged with one or both of the drive shaft hole 91 and the anvil hole 92.
- the coupling member 93 is rotatably coupled to a switching shaft 94.
- the switching shaft 94 moves in the axial direction in cooperation with the movement of a switch (not shown).
- a stopper 95 is fixed to a distal end of the switching shaft 94 to restrict axial movement of the switching shaft 94 relative to the coupling member 93.
- the axial movement of the switching shaft 94 axially moves the coupling member 93 in the drive shaft hole 91.
- the rotation tool 81 is in the impact mode, which permits relative rotation of the drive shaft 83 and the anvil 82 (hammer 84).
- the rotation tool 81 is in the drill mode, which restricts relative rotation of the drive shaft 83 and the anvil 82 (hammer 84).
- the drive shaft 83 When, for example, the drive shaft 83 is inclined due to manufacturing or assembling errors of components, a portion of the coupling member 93 may be strongly forced against the wall of the drive shaft hole 91.
- a regulated clearance is provided between the drive shaft 83 and the anvil 82.
- the drive shaft 83 moves within the range of the clearance. If a portion of the coupling member 93 is forced strongly against the wall of the drive shaft hole 91, friction would occur where the coupling member 93 contacts the wall of the drive shaft hole 91. This would push the coupling member 93 with a strong force toward the anvil 82. Further, the stopper 95 would repetitively receive a strong force from the coupling member 93. This may shorten the life of the stopper 95.
- One aspect of the present invention is an impact rotation tool including a drive shaft rotated and driven by a rotational power source.
- the drive shaft includes a drive shaft hole.
- An anvil is coaxial with the drive shaft and rotatable relative to the drive shaft.
- the anvil includes an anvil hole.
- a hammer is rotated by the drive shaft and engaged with the anvil.
- the hammer is coupled to the drive shaft so that the hammer moves away from the anvil in an axial direction of the drive shaft when the hammer rotates relative to the drive shaft.
- An urging member urges the hammer toward the anvil.
- a switching mechanism switches the impact rotation tool between an impact mode that impacts the anvil with the hammer and a drill mode that integrally rotates the drive shaft and the anvil.
- the switching mechanism includes a coupling member movable between a position where the coupling member is engaged with a wall of only one of the drive shaft hole and the anvil hole and a position where the coupling member is engaged with the walls of both of the drive shaft hole and the anvil hole.
- a switching shaft supports the coupling member to be rotatable and moves the coupling member in the axial direction.
- a stopper restricts axial movement of the coupling member relative to the switching shaft.
- the switching shaft moves the coupling member to the position where the coupling member is engaged with the wall of only the drive shaft hole to switch to the impact mode.
- the switching shaft moves the coupling member to the position where the coupling member is engaged with the walls of both of the drive shaft hole and the anvil hole to switch to the drill mode.
- the wall of the drive shaft hole includes an engagement portion engaged with the coupling member in the impact mode, and a relief formed so as not to contact an outer circumferential surface of the coupling member in the impact mode.
- the impact rotation tool further includes an elastic member arranged between the coupling member and the stopper.
- the relief of the drive shaft hole is formed to form a clearance between the coupling member and the drive shaft.
- the coupling member includes a distal portion and a basal portion; in the drill mode, the distal portion of the coupling member engages with the inner surface of the anvil hole, and the basal portion of the coupling member is engaged with the engagement portion of the drive shaft hole, and the basal portion of the coupling member is engaged with the engagement portion of the drive shaft hole; and in the impact mode, the distal portion of the coupling member is engaged with the engagement portion of the drive shaft hole, and the basal portion of the coupling member is separated from the relief of the drive shaft hole in a radially inner direction.
- the engagement portion includes an inner diameter substantially equal to an outer diameter of the coupling member, and the relief has an inner diameter that is substantially larger than the outer diameter of the coupling member.
- the drive shaft includes a distal end supported to be rotatable by the anvil, and the relief is located in the drive shaft hole at a position that is farther from the distal end of the drive shaft than the engagement portion.
- the present invention provides an impact rotation tool that does not shorten the stopper life.
- an impact rotation tool 1 is hand-held and may be used as, for example, an impact driver and a drill driver.
- the impact rotation tool 1 has a T-shaped housing 2 including a cylindrical barrel 2a and a grip 2b, which extends from a lower side of the barrel 2a.
- the lower end of the grip 2b forms a battery pack seat 2c.
- a battery pack 3 is attached in a removable manner to the battery pack seat 2c.
- the grip 2b includes a trigger switch 4 that activates and deactivates the impact rotation tool 1.
- the longitudinal direction of the barrel 2a is referred to as a front-to-rear direction.
- a rear portion of the barrel 2a accommodates a motor 5, which serves as a rotational power source.
- the motor 5 is coupled to a power transmission unit 7, which reduces the speed of the rotation generated by the motor 5 and transmits the rotation to a drive shaft 6.
- An impact generator 8 is arranged in front of the power transmission unit 7 to generate pulsed torque from the rotation of the drive shaft 6.
- a chuck 9 that holds a tip tool (not shown) in a removable manner is arranged on the front end of the barrel 2a.
- the power transmission unit 7 will now be described.
- the power transmission unit 7 includes a gear case 11, which is fixed to the inner side of the barrel 2a, a speed reduction unit 12, which is accommodated in the gear case 11, and a clutch mechanism 13, which regulates the torque of the motor 5 transmitted to the drive shaft 6 by the speed reduction unit 12.
- the gear case 11 is cup-shaped and includes an open rear end.
- a support tube 11b projects toward the front from a front end 11a of the gear case 11.
- the speed reduction unit 12 is a planetary gear unit including first and second speed reduction mechanisms 12a and 12b arranged in order from the rear, that is, from the motor 5.
- the motor 5 includes a rotation shaft 5a.
- the first speed reduction mechanism 12a includes a first sun gear 21a rotated integrally with the rotation shaft 5a of the motor 5.
- the first speed reduction mechanism 12a includes a plurality of first planet gears 22a engaged with the first sun gear 21a, a first ring gear 23a engaged with the first planet gears 22a, and a first carrier 24a rotatably supporting the first planet gears 22a.
- the first ring gear 23a is fixed to the gear case 11 so that rotation about the axis of the rotation shaft 5a is prohibited.
- Each first planet gear 22a is rotatably supported by a first coupling pin 25a on the first carrier 24a. Rotation of the rotation shaft 5a rotates each first planet gear 22a about the axis of the corresponding first coupling pin 25a as the first planet gear 22a orbits about the first sun gear 21a.
- the first carrier 24a holds a movable carrier 26 with the first coupling pins 25a.
- the movable carrier 26 is rotatable integrally with the first carrier 24a and movable axially relative to the first carrier 24a.
- a link 27 connects the movable carrier 26 to a switch 28, which is arranged on the housing 2.
- the switch 28 is slidable toward the front and rear.
- the movable carrier 26 moves toward the front and rear in the axial direction in cooperation with the movement of the switch 28.
- the link 27 is, for example, an arcuate wire spring extending in the circumferential direction.
- the link 27 is coupled to an annular groove 29 formed in the outer circumferential surface of the movable carrier 26.
- the second speed reduction mechanism 12b includes a second sun gear 21b arranged integrally with the front surface of the movable carrier 26.
- the second speed reduction mechanism 12b includes a plurality of second planet gears 22b arranged around and engaged with the second sun gear 21b when the movable carrier 26 (second sun gear 21b) is moved toward the front (refer to Fig. 3 ).
- the second speed reduction mechanism 12b includes a second ring gear 23b, which is engaged with the second planet gears 22b, and a second carrier 24b, which rotatably supports the second planet gears 22b with second coupling pins 25b.
- a coupling shaft 31 projecting toward the front is formed integrally with the second sun gear 21b.
- a through hole 32 axially extends through the coupling shaft 31.
- the coupling shaft 31 has a front end forming a gear-shaped direct coupling portion 33.
- a coupling tube 34 which projects toward the front, is formed integrally with the second carrier 24b.
- the coupling tube 34 includes a rear end that forms a direct coupling portion 35 engaged with the direct coupling portion 33 so as to rotate integrally with the direct coupling portion 33.
- the second ring gear 23b is rotatably arranged in the gear case 11.
- the clutch mechanism 13 restricts rotation of the second ring gear 23b when the load torque applied to the second ring gear 23b is less than or equal to a predetermined torque.
- the load torque is greater than the predetermined torque, the second ring gear 23b rotates freely.
- the clutch mechanism 13 includes a clutch plate 44, a clutch spring 45, and an adjustment member 46.
- the clutch spring 45 urges the balls 43 toward the second ring gear 23b with the clutch plate 44.
- the adjustment member 46 is fastened to the support tube 11b of the gear case 11 and allows for adjustment of the compression amount of the clutch spring 45.
- the clutch mechanism 13 restricts rotation of the second ring gear 23b. This rotates the second carrier 24b and transmits the output of the speed reduction unit 12 to the drive shaft 6.
- the second ring gear 23b pushes back the balls 43 and rotates freely.
- the second carrier 24b is not rotated, and the output of the speed reduction unit 12 is not transmitted to the drive shaft 6.
- the impact generator 8 will now be described.
- the impact generator 8 includes the drive shaft 6, an anvil 51, a hammer 52, and a hammer spring 53 serving as an urging member.
- the anvil 51 is coaxial with the drive shaft 6 and rotatable relative to the drive shaft 6.
- the hammer 52 is coupled to the drive shaft 6.
- the hammer spring 53 urges the hammer 52 toward the anvil 51.
- the axis of the drive shaft 6 extends in the front-to-rear direction.
- the drive shaft 6 includes a drive shaft hole 54 that opens toward the front, that is, toward the anvil 51.
- An insertion hole 55 axially extends through the drive shaft 6 and is in communication with the drive shaft hole 54.
- the axis of the anvil 51 extends in the front-to-rear direction.
- the anvil 51 includes a front end that receives the basal end of a tip tool.
- the chuck 9 holds a tip tool so that the tip tool rotates integrally with the anvil 51.
- the anvil 51 includes a plurality of arms 51a that extend toward the outer side in the radial direction. In the example of Fig. 4 , two arms 51a are arranged at an interval of 180°. As shown in Figs. 2(b) and 3(b) , the anvil 51 includes a support hole 57 that is open at the rear side toward the drive shaft 6. The support hole 57 is coaxial with the drive shaft 6. The anvil 51 includes an anvil hole 58 that is in communication with the support hole 57 and coaxial with the drive shaft hole 54. The front end of the drive shaft 6 is fitted into the support hole 57 and rotatably supported by the anvil 51. An axial clearance is provided between the front end of the drive shaft 6 and the anvil 51 to permit slight axial movement of the drive shaft 6.
- the hammer 52 is engaged with the anvil 51 when rotated by the drive shaft 6.
- the hammer 52 is annular. Hooks 52a project toward the front from the front surface of the hammer 52. The rotation of the hammer 52 engages the hooks 52a with the arms 51a of the anvil 51. In the illustrated example, the two hooks 52a, which are trapezoidal, are arranged at an interval of 180°.
- the hammer spring 53 is held in a compressed state and arranged between the anvil 51 and an annular spring seat 62, which is fixed to the drive shaft 6.
- the hammer spring 53 is, for example, a coil spring.
- the hammer 52 moves away from the anvil 51.
- the hammer 52 is cam-coupled to the drive shaft 6.
- the outer circumferential surface of the drive shaft 6 includes a cam groove 63 having an inclination angle (lead angle) relative to the axis of the drive shaft 6.
- the inner circumferential surface of the hammer 52 includes a linear cam groove 64. Balls 65 are held between the cam grooves 63 and 64.
- the hammer 52 is coupled to the drive shaft 6 with the balls 65 arranged in between.
- the hammer 52 rotates relative to the drive shaft 6. Further, when the balls 65 roll between the cam grooves 63 and 64, the hammer 52 moves away from the anvil 51 against the urging force of the hammer spring 53. When the hooks 52a move over the arms 51a, the hammer 52 is moved toward the anvil 51 by the urging force of the hammer spring 53 while rotating, and the hammer 52 impacts the arms 51a with the hooks 52a. Such an impact action is intermittently repeated as the drive shaft 6 rotates.
- the impact generator 8 includes a switching mechanism 71 that switches between an impact mode, in which the hammer 52 impacts the anvil 51, and a drill mode, in which the anvil 51 is rotated integrally with the drive shaft 6.
- the switching mechanism 71 includes a coupling member 72, a switching shaft 73, and a stopper pin 77.
- the coupling member 72 is engageable with the walls of one or both of the drive shaft hole 54 and the anvil hole 58.
- the switching shaft 73 supports the coupling member 72 in a relatively rotatable manner.
- the switching shaft 73 moves in the axial direction in cooperation with the movement of the switch 28.
- the stopper pin 77 restricts the axial movement of the coupling member 72 relative to the switching shaft 73.
- the switching shaft 73 moves the coupling member 72 in the axial direction in accordance with the movement of the switch 28.
- the switch shaft 73 switches to the impact mode by moving the coupling member 72 to a location where the coupling member 72 is engaged with only the wall of the drive shaft hole 54.
- the impact mode relative rotation is permitted between the drive shaft 6 and the anvil 51 (hammer 52).
- the switch shaft 73 switches to the drill mode by moving the coupling member 72 to a location where the coupling member 72 is engaged with the walls of both of the drive shaft hole 54 and the anvil hole 58. In the drill mode, relative rotation is restricted between the drive shaft 6 and the anvil 51 (hammer 52).
- the coupling member 72 is hexagonal.
- a fitting hole 74 axially extends through the coupling member 72.
- the coupling member 72 has an axial length set to be shorter than the drive shaft hole 54, and the coupling member 72 may be completely accommodated in the drive shaft hole 54.
- the wall of the drive shaft hole 54 includes an engagement portion 75, which is engaged with the coupling member 72 in the impact mode, and a relief 76, which does not contact the outer surface of the coupling member 72 in the impact mode.
- the engagement portion 75 has a hexagonal cross-section of which inner diameter is substantially the same as the outer diameter of the coupling member 72 (diameter of inscribed circuit of the hexagon formed by the cross-section of the coupling member 72).
- the relief 76 has a hexagonal cross-section with an inner diameter that is larger than the outer diameter of the coupling member 72.
- the relief 76 is an annular groove extending in the circumferential direction of the drive shaft 6 and formed in a wall surface of a rear side of the engagement portion 75.
- the engagement portion 75 is formed in an axial range that allows for the engagement portion 75 to receive the front end of the coupling member 72 during the impact mode and prevent the rear end of the coupling member 72 from entering the relief 76 during the drill mode.
- the entire anvil hole 58 has a hexagonal cross-section in the axial direction and an inner diameter that is generally the same as the outer diameter of the coupling member 72.
- the front end of the switching shaft 73 includes a small diameter portion 73a having a smaller diameter than the rear side of the switching shaft 73.
- the coupling member 72 is rotatably fitted to the small diameter portion 73a.
- the stopper pin 77 is fixed to the front end of the small diameter portion 73a (end facing the anvil 51).
- the stopper pin 77 serves as a stopper that is adjacent to the front surface of the coupling member 72.
- the stopper pin 77 is fixed to the switching shaft 73 in a direction perpendicular to the switching shaft 73.
- the coupling member 72 is held between a step 73b of the switching shaft 73 and the stopper pin 77 to restrict axial movement of the coupling member 72 relative to the switching shaft 73.
- the front surface of the coupling member 72 includes a recess 78.
- An elastic member 79 made of rubber or the like is arranged in the recess 78.
- the recess 78 is a round hole having a larger diameter than the axial length of the stopper pin 77.
- the coupling member 72 does not directly contact the stopper pin 77, and the elastic member 79 is arranged between the coupling member 72 and the stopper pin 77.
- the switching shaft 73 is inserted through the insertion hole 55 of the drive shaft 6 so that the rear end of the switching shaft 73 projects from the drive shaft 6 toward the rear.
- the rear end of the switching shaft 73 is fitted under pressure into the through hole 32 of the second sun gear 21b.
- the switching shaft 73 is fixed to the second sun gear 21b to be rotatable integrally with the second sun gear 21b and immovable in the axial direction relative to the second sun gear 21b.
- the switching shaft 73 moves in the axial direction integrally with the second sun gear 21b (movable carrier 26) in cooperation with the movement of the switch 28.
- the switch 28 When using the impact rotation tool 1 as an impact driver, the switch 28 is moved toward the rear to move the coupling member 72 with the switching shaft 73 toward the rear. As a result, the coupling member 72 engages with the wall of only the drive shaft hole 54, and the rotation tool 1 enters the impact mode.
- the coupling member 72 In the example shown in Fig. 2(b) , during the impact mode, the coupling member 72 is completely accommodated in the drive shaft hole 54 and does not enter the anvil hole 58. In the impact mode, the impact torque generated by impact actions rotates the anvil 51 and tightens a screw or the like.
- the switch 28 When using the impact rotation tool 1 as a drill driver, the switch 28 is moved toward the front to move the coupling member 72 with the switching shaft 73 toward the front. As a result, the coupling member 72 engages with the walls of both of the drive shaft hole 54 and the anvil hole 58, and the rotation tool 1 enters the drill mode. As shown in Fig. 3(b) , in the drill mode, the boundary between the drive shaft 6 and the anvil 51 lies along the coupling member 72. In the drill mode, the torque of the motor 5 is reduced in speed by the speed reduction mechanisms 12a and 12b and transmitted to the drive shaft 6 in order to rotate the anvil 51 and tighten a screw or the like.
- a regulated clearance in the axial direction is provided between the drive shaft 6 and the anvil 51.
- the drive shaft 6 moves toward the anvil 51 whenever an impact action is produced.
- frictional force is produced where the coupling member 72 contacts the drive shaft 6. This pushes the coupling member 72 against the stopper pin 77 in accordance with the frictional force. Due to errors in assembled components or the like, the frictional force produced between the drive shaft 6 and the coupling member 72 may strongly force a portion of the coupling member 72 against the wall of the drive shaft hole 54.
- the wall of the drive shaft hole 54 in the present embodiment includes the relief 76.
- the coupling member 72 is not pushed by a strong force.
- a large force is not applied to the stopper pin 77 by the coupling member 72.
- the force applied to the stopper pin 77 from the coupling member 72 is absorbed by the elastic deformation of the elastic member 79, which is arranged between the coupling member 72 and the stopper pin 77.
- the wall of the drive shaft hole 54 includes the engagement portion 75.
- the coupling member 72 is not rotated relative to the drive shaft 6 in the drive shaft hole 54.
- the edge of the coupling member 72 does not contact the wall of the drive shaft hole 54, and the application of excessive load to the drive shaft 6 is suppressed.
- the present embodiment has the advantages described below.
- a coil spring is used as the hammer spring 53 serving as an urging member that urges the hammer 52 toward the anvil 51.
- the hammer spring 53 may be a Belleville spring or the like.
- the stopper does not have to be the stopper pin 77 and may instead be a snap ring or the like.
- the elastic member 79 which is made of rubber or the like, may be arranged between the coupling member 72 and the stopper pin 77.
- the relief 76 is an annular groove extending in the circumferential direction of the drive shaft 6 and formed at the rear side of the inner circumferential surface of the engagement portion 75.
- the relief 76 may be formed by a linear groove extending in the axial direction.
- a plurality of (six) reliefs 76 are formed at equal angular intervals in the circumferential direction.
- the drive shaft hole 54, the anvil hole 58, and the coupling member 72 have hexagonal cross-sections.
- the drive shaft hole 54, the anvil hole 58, and the coupling member 72 may have any non-circular cross-section as long as the rotation of the coupling member 72 may be transmitted to the drive shaft hole 54 and the anvil hole 58.
- the cross-section may be square, elliptic, or D-shaped.
- the rotational power source is not limited to the motor 5 and may be, for example, a hydraulic or pneumatic rotational power source.
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Description
- The present invention relates to an impact rotation tool.
- An impact rotation tool includes a hammer coupled to a drive shaft, which is rotated and driven by a motor. The hammer impacts an anvil to generate an impact torque used by the impact rotation tool to tighten a screw. Japanese Patent No.
3911905 - Referring to
Fig. 7 , the '905 patent describes animpact rotation tool 81 that includes ananvil 82, which is coaxial with and rotatable relative to adrive shaft 83. Ahammer 84, which includes ahook 84a, is coupled to thedrive shaft 83. When thehammer 84 is rotated, thehook 84a is engaged with a portion of anarm 82a of theanvil 82. A hammer spring 85 urges thehammer 84 toward theanvil 82. When the load torque transmitted to theanvil 82 by thehammer 84 exceeds a predetermined value, thedrive shaft 83 and the hammer 84 (anvil) rotate relative to each other. This moves thehammer 84 away from theanvil 82 against the urging force of the hammer spring 85. Then, when thehook 84a moves over thearm 82a as thehammer 84 rotates, the urging force of the hammer spring 85 moves thehammer 84 toward theanvil 82, and thehook 84a impacts thearm 82a. This rotates theanvil 82 again. Such an impact action is repeated as thedrive shaft 83 rotates. - The
drive shaft 83 includes adrive shaft hole 91 having a hexagonal cross-section. Thedrive shaft hole 91 faces theanvil 82 at a distal end of thedrive shaft 83. Theanvil 82 includes ananvil hole 92 having a hexagonal cross-section and facing toward thedrive shaft 83. Ahexagonal coupling member 93 is arranged in thedrive shaft hole 91. Thecoupling member 93 is movable in the axial direction inside thedrive shaft hole 91. Further, thecoupling member 93 is engaged with one or both of thedrive shaft hole 91 and theanvil hole 92. Thecoupling member 93 is rotatably coupled to a switchingshaft 94. Theswitching shaft 94 moves in the axial direction in cooperation with the movement of a switch (not shown). Astopper 95 is fixed to a distal end of theswitching shaft 94 to restrict axial movement of theswitching shaft 94 relative to thecoupling member 93. The axial movement of theswitching shaft 94 axially moves thecoupling member 93 in thedrive shaft hole 91. For example, when thecoupling member 93 is engaged with the wall of thedrive shaft hole 91 but not with the wall of theanvil hole 92, therotation tool 81 is in the impact mode, which permits relative rotation of thedrive shaft 83 and the anvil 82 (hammer 84). When thecoupling member 93 is engaged with the walls of both of thedrive shaft hole 91 and theanvil hole 92, therotation tool 81 is in the drill mode, which restricts relative rotation of thedrive shaft 83 and the anvil 82 (hammer 84). - When, for example, the
drive shaft 83 is inclined due to manufacturing or assembling errors of components, a portion of thecoupling member 93 may be strongly forced against the wall of thedrive shaft hole 91. A regulated clearance is provided between thedrive shaft 83 and theanvil 82. When thehammer 84 moves in the axial direction during an impact action, thedrive shaft 83 moves within the range of the clearance. If a portion of thecoupling member 93 is forced strongly against the wall of thedrive shaft hole 91, friction would occur where thecoupling member 93 contacts the wall of thedrive shaft hole 91. This would push thecoupling member 93 with a strong force toward theanvil 82. Further, thestopper 95 would repetitively receive a strong force from thecoupling member 93. This may shorten the life of thestopper 95. - It is an object of the present invention to provide an impact rotation tool that does not shorten the stopper life.
- One aspect of the present invention is an impact rotation tool including a drive shaft rotated and driven by a rotational power source. The drive shaft includes a drive shaft hole. An anvil is coaxial with the drive shaft and rotatable relative to the drive shaft. The anvil includes an anvil hole. A hammer is rotated by the drive shaft and engaged with the anvil. The hammer is coupled to the drive shaft so that the hammer moves away from the anvil in an axial direction of the drive shaft when the hammer rotates relative to the drive shaft. An urging member urges the hammer toward the anvil. A switching mechanism switches the impact rotation tool between an impact mode that impacts the anvil with the hammer and a drill mode that integrally rotates the drive shaft and the anvil. The switching mechanism includes a coupling member movable between a position where the coupling member is engaged with a wall of only one of the drive shaft hole and the anvil hole and a position where the coupling member is engaged with the walls of both of the drive shaft hole and the anvil hole. A switching shaft supports the coupling member to be rotatable and moves the coupling member in the axial direction. A stopper restricts axial movement of the coupling member relative to the switching shaft. The switching shaft moves the coupling member to the position where the coupling member is engaged with the wall of only the drive shaft hole to switch to the impact mode. The switching shaft moves the coupling member to the position where the coupling member is engaged with the walls of both of the drive shaft hole and the anvil hole to switch to the drill mode. The wall of the drive shaft hole includes an engagement portion engaged with the coupling member in the impact mode, and a relief formed so as not to contact an outer circumferential surface of the coupling member in the impact mode.
- Preferably, the impact rotation tool further includes an elastic member arranged between the coupling member and the stopper.
- Preferably, the relief of the drive shaft hole is formed to form a clearance between the coupling member and the drive shaft.
- Preferably, the coupling member includes a distal portion and a basal portion; in the drill mode, the distal portion of the coupling member engages with the inner surface of the anvil hole, and the basal portion of the coupling member is engaged with the engagement portion of the drive shaft hole, and the basal portion of the coupling member is engaged with the engagement portion of the drive shaft hole; and in the impact mode, the distal portion of the coupling member is engaged with the engagement portion of the drive shaft hole, and the basal portion of the coupling member is separated from the relief of the drive shaft hole in a radially inner direction.
- Preferably, the engagement portion includes an inner diameter substantially equal to an outer diameter of the coupling member, and the relief has an inner diameter that is substantially larger than the outer diameter of the coupling member.
- Preferably, the drive shaft includes a distal end supported to be rotatable by the anvil, and the relief is located in the drive shaft hole at a position that is farther from the distal end of the drive shaft than the engagement portion.
- The present invention provides an impact rotation tool that does not shorten the stopper life.
- Other aspects and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
- The novel features which are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself and additional objects and advantages thereof will best be understood from the following description of embodiments thereof when read in connection with the accompanying drawings, in which:
-
Fig. 1 is a perspective view showing one embodiment of an impact rotation tool; -
Fig. 2(a) is a schematic partial cross-sectional view of the impact rotation tool in an impact mode; -
Fig. 2(b) is a partially enlarged view ofFig. 2(a) ; -
Fig. 3(a) is a schematic partial cross-sectional view of the impact rotation tool in a drill mode; -
Fig. 3(b) is a partially enlarged view ofFig. 3(a) ; -
Fig. 4 is a cross-sectional view of the impact rotation tool taken along line A-A inFig. 2(a) ; -
Fig. 5 is a cross-sectional view of the impact rotation tool taken along line B-B inFig. 2(b) ; -
Fig. 6 is a cross-sectional view showing another example a drive shaft including a relief; and -
Fig. 7 is a partial cross-sectional view showing an impact rotation tool of the prior art. - One embodiment of an impact rotation tool will now be described.
- In the example shown in
Fig. 1 , an impact rotation tool 1 is hand-held and may be used as, for example, an impact driver and a drill driver. In the illustrated example, the impact rotation tool 1 has a T-shapedhousing 2 including acylindrical barrel 2a and agrip 2b, which extends from a lower side of thebarrel 2a. The lower end of thegrip 2b forms a battery pack seat 2c. A battery pack 3 is attached in a removable manner to the battery pack seat 2c. Thegrip 2b includes atrigger switch 4 that activates and deactivates the impact rotation tool 1. In the description hereafter, the longitudinal direction of thebarrel 2a is referred to as a front-to-rear direction. - Referring to
Figs. 2(a) and3(a) , a rear portion of thebarrel 2a accommodates amotor 5, which serves as a rotational power source. Themotor 5 is coupled to apower transmission unit 7, which reduces the speed of the rotation generated by themotor 5 and transmits the rotation to adrive shaft 6. Animpact generator 8 is arranged in front of thepower transmission unit 7 to generate pulsed torque from the rotation of thedrive shaft 6. Achuck 9 that holds a tip tool (not shown) in a removable manner is arranged on the front end of thebarrel 2a. - The
power transmission unit 7 will now be described. - The
power transmission unit 7 includes a gear case 11, which is fixed to the inner side of thebarrel 2a, aspeed reduction unit 12, which is accommodated in the gear case 11, and aclutch mechanism 13, which regulates the torque of themotor 5 transmitted to thedrive shaft 6 by thespeed reduction unit 12. The gear case 11 is cup-shaped and includes an open rear end. A support tube 11b projects toward the front from a front end 11a of the gear case 11. - In the illustrated example, the
speed reduction unit 12 is a planetary gear unit including first and secondspeed reduction mechanisms motor 5. Themotor 5 includes arotation shaft 5a. The firstspeed reduction mechanism 12a includes afirst sun gear 21a rotated integrally with therotation shaft 5a of themotor 5. Further, the firstspeed reduction mechanism 12a includes a plurality offirst planet gears 22a engaged with thefirst sun gear 21a, afirst ring gear 23a engaged with thefirst planet gears 22a, and afirst carrier 24a rotatably supporting thefirst planet gears 22a. Thefirst ring gear 23a is fixed to the gear case 11 so that rotation about the axis of therotation shaft 5a is prohibited. Eachfirst planet gear 22a is rotatably supported by afirst coupling pin 25a on thefirst carrier 24a. Rotation of therotation shaft 5a rotates eachfirst planet gear 22a about the axis of the correspondingfirst coupling pin 25a as thefirst planet gear 22a orbits about thefirst sun gear 21a. - The
first carrier 24a holds amovable carrier 26 with thefirst coupling pins 25a. Themovable carrier 26 is rotatable integrally with thefirst carrier 24a and movable axially relative to thefirst carrier 24a. A link 27 connects themovable carrier 26 to aswitch 28, which is arranged on thehousing 2. Theswitch 28 is slidable toward the front and rear. Themovable carrier 26 moves toward the front and rear in the axial direction in cooperation with the movement of theswitch 28. The link 27 is, for example, an arcuate wire spring extending in the circumferential direction. The link 27 is coupled to anannular groove 29 formed in the outer circumferential surface of themovable carrier 26. - The second
speed reduction mechanism 12b includes asecond sun gear 21b arranged integrally with the front surface of themovable carrier 26. The secondspeed reduction mechanism 12b includes a plurality of second planet gears 22b arranged around and engaged with thesecond sun gear 21b when the movable carrier 26 (second sun gear 21b) is moved toward the front (refer toFig. 3 ). Further, the secondspeed reduction mechanism 12b includes a second ring gear 23b, which is engaged with the second planet gears 22b, and a second carrier 24b, which rotatably supports the second planet gears 22b with second coupling pins 25b. Acoupling shaft 31 projecting toward the front is formed integrally with thesecond sun gear 21b. A throughhole 32 axially extends through thecoupling shaft 31. Thecoupling shaft 31 has a front end forming a gear-shapeddirect coupling portion 33. Acoupling tube 34, which projects toward the front, is formed integrally with the second carrier 24b. Thecoupling tube 34 includes a rear end that forms adirect coupling portion 35 engaged with thedirect coupling portion 33 so as to rotate integrally with thedirect coupling portion 33. In one example, the second ring gear 23b is rotatably arranged in the gear case 11. When thecoupling tube 34 is arranged in the support tube 11b of the gear case 11, the second carrier 24b is supported to be rotatable relative to the gear case 11. - Referring to
Fig. 2(a) , when themovable carrier 26 is located at the rear of the gear case 11 in thespeed reduction unit 12, thedirect coupling portion 33 of thesecond sun gear 21b is engaged with thedirect coupling portion 35 of the second carrier 24b, and thesecond sun gear 21b rotates integrally with the second carrier 24b. Thus, only the firstspeed reduction mechanism 12a transmits the rotation generated by themotor 5 to thedrive shaft 6. Referring toFig. 3(a) , when themovable carrier 26 is located at the front of the gear case 11, thedirect coupling portions second sun gear 21b is engaged with the second planet gears 22b. Thus, the first andspeed reduction mechanism motor 5 to thedrive shaft 6. - When the
second sun gear 21b is engaged with the second planet gears 22b as shown inFig. 3 (drill mode), theclutch mechanism 13 restricts rotation of the second ring gear 23b when the load torque applied to the second ring gear 23b is less than or equal to a predetermined torque. When the load torque is greater than the predetermined torque, the second ring gear 23b rotates freely. - More specifically, a plurality of projections (not shown) axially project from the front surface of the second ring gear 23b at equal angular intervals.
Balls 43 engaged with the projections are received in insertion holes (not shown) arranged in the front end 11a of the gear case 11. Theclutch mechanism 13 includes aclutch plate 44, aclutch spring 45, and anadjustment member 46. Theclutch spring 45 urges theballs 43 toward the second ring gear 23b with theclutch plate 44. Theadjustment member 46 is fastened to the support tube 11b of the gear case 11 and allows for adjustment of the compression amount of theclutch spring 45. Accordingly, when the load torque applied to the second ring gear 23b is lower than the engagement force between the projections and theballs 43, which are urged by theclutch spring 45, theclutch mechanism 13 restricts rotation of the second ring gear 23b. This rotates the second carrier 24b and transmits the output of thespeed reduction unit 12 to thedrive shaft 6. When the load torque applied to the second ring gear 23b is higher than the engagement force between the projections and theballs 43, the second ring gear 23b pushes back theballs 43 and rotates freely. Thus, the second carrier 24b is not rotated, and the output of thespeed reduction unit 12 is not transmitted to thedrive shaft 6. - The
impact generator 8 will now be described. - The
impact generator 8 includes thedrive shaft 6, ananvil 51, ahammer 52, and ahammer spring 53 serving as an urging member. Theanvil 51 is coaxial with thedrive shaft 6 and rotatable relative to thedrive shaft 6. Thehammer 52 is coupled to thedrive shaft 6. Thehammer spring 53 urges thehammer 52 toward theanvil 51. The axis of thedrive shaft 6 extends in the front-to-rear direction. As shown inFigs. 2(b) and3(b) , thedrive shaft 6 includes adrive shaft hole 54 that opens toward the front, that is, toward theanvil 51. Aninsertion hole 55 axially extends through thedrive shaft 6 and is in communication with thedrive shaft hole 54. - The axis of the
anvil 51 extends in the front-to-rear direction. Theanvil 51 includes a front end that receives the basal end of a tip tool. Thechuck 9 holds a tip tool so that the tip tool rotates integrally with theanvil 51. - The
anvil 51 includes a plurality ofarms 51a that extend toward the outer side in the radial direction. In the example ofFig. 4 , twoarms 51a are arranged at an interval of 180°. As shown inFigs. 2(b) and3(b) , theanvil 51 includes asupport hole 57 that is open at the rear side toward thedrive shaft 6. Thesupport hole 57 is coaxial with thedrive shaft 6. Theanvil 51 includes ananvil hole 58 that is in communication with thesupport hole 57 and coaxial with thedrive shaft hole 54. The front end of thedrive shaft 6 is fitted into thesupport hole 57 and rotatably supported by theanvil 51. An axial clearance is provided between the front end of thedrive shaft 6 and theanvil 51 to permit slight axial movement of thedrive shaft 6. - The
hammer 52 is engaged with theanvil 51 when rotated by thedrive shaft 6. In the example shown inFig. 4 , thehammer 52 is annular.Hooks 52a project toward the front from the front surface of thehammer 52. The rotation of thehammer 52 engages thehooks 52a with thearms 51a of theanvil 51. In the illustrated example, the twohooks 52a, which are trapezoidal, are arranged at an interval of 180°. As shown inFigs. 2(a) and3(a) , thehammer spring 53 is held in a compressed state and arranged between theanvil 51 and anannular spring seat 62, which is fixed to thedrive shaft 6. Thehammer spring 53 is, for example, a coil spring. - When the
hammer 52 and thedrive shaft 6 rotate relative to each other, thehammer 52 moves away from theanvil 51. Thehammer 52 is cam-coupled to thedrive shaft 6. For example, the outer circumferential surface of thedrive shaft 6 includes acam groove 63 having an inclination angle (lead angle) relative to the axis of thedrive shaft 6. The inner circumferential surface of thehammer 52 includes alinear cam groove 64.Balls 65 are held between thecam grooves hammer 52 is coupled to thedrive shaft 6 with theballs 65 arranged in between. - Due to the cam coupling, in the
impact generator 8, thehammer 52 rotates relative to thedrive shaft 6. Further, when theballs 65 roll between thecam grooves hammer 52 moves away from theanvil 51 against the urging force of thehammer spring 53. When thehooks 52a move over thearms 51a, thehammer 52 is moved toward theanvil 51 by the urging force of thehammer spring 53 while rotating, and thehammer 52 impacts thearms 51a with thehooks 52a. Such an impact action is intermittently repeated as thedrive shaft 6 rotates. - The
impact generator 8 includes aswitching mechanism 71 that switches between an impact mode, in which thehammer 52 impacts theanvil 51, and a drill mode, in which theanvil 51 is rotated integrally with thedrive shaft 6. Theswitching mechanism 71 includes acoupling member 72, a switchingshaft 73, and astopper pin 77. Thecoupling member 72 is engageable with the walls of one or both of thedrive shaft hole 54 and theanvil hole 58. The switchingshaft 73 supports thecoupling member 72 in a relatively rotatable manner. The switchingshaft 73 moves in the axial direction in cooperation with the movement of theswitch 28. Thestopper pin 77 restricts the axial movement of thecoupling member 72 relative to the switchingshaft 73. The switchingshaft 73 moves thecoupling member 72 in the axial direction in accordance with the movement of theswitch 28. For example, theswitch shaft 73 switches to the impact mode by moving thecoupling member 72 to a location where thecoupling member 72 is engaged with only the wall of thedrive shaft hole 54. In the impact mode, relative rotation is permitted between thedrive shaft 6 and the anvil 51 (hammer 52). Further, theswitch shaft 73 switches to the drill mode by moving thecoupling member 72 to a location where thecoupling member 72 is engaged with the walls of both of thedrive shaft hole 54 and theanvil hole 58. In the drill mode, relative rotation is restricted between thedrive shaft 6 and the anvil 51 (hammer 52). - In the example shown in
Figs. 2(b) and3(b) , thecoupling member 72 is hexagonal. Afitting hole 74 axially extends through thecoupling member 72. Thecoupling member 72 has an axial length set to be shorter than thedrive shaft hole 54, and thecoupling member 72 may be completely accommodated in thedrive shaft hole 54. - As shown in
Fig. 2(b) , the wall of thedrive shaft hole 54 includes anengagement portion 75, which is engaged with thecoupling member 72 in the impact mode, and arelief 76, which does not contact the outer surface of thecoupling member 72 in the impact mode. As shown inFig. 4 , theengagement portion 75 has a hexagonal cross-section of which inner diameter is substantially the same as the outer diameter of the coupling member 72 (diameter of inscribed circuit of the hexagon formed by the cross-section of the coupling member 72). As shown inFig. 5 , therelief 76 has a hexagonal cross-section with an inner diameter that is larger than the outer diameter of thecoupling member 72. For example, therelief 76 is an annular groove extending in the circumferential direction of thedrive shaft 6 and formed in a wall surface of a rear side of theengagement portion 75. Theengagement portion 75 is formed in an axial range that allows for theengagement portion 75 to receive the front end of thecoupling member 72 during the impact mode and prevent the rear end of thecoupling member 72 from entering therelief 76 during the drill mode. Further, theentire anvil hole 58 has a hexagonal cross-section in the axial direction and an inner diameter that is generally the same as the outer diameter of thecoupling member 72. - The front end of the switching
shaft 73 includes asmall diameter portion 73a having a smaller diameter than the rear side of the switchingshaft 73. Thecoupling member 72 is rotatably fitted to thesmall diameter portion 73a. Thestopper pin 77 is fixed to the front end of thesmall diameter portion 73a (end facing the anvil 51). Thestopper pin 77 serves as a stopper that is adjacent to the front surface of thecoupling member 72. For example, thestopper pin 77 is fixed to the switchingshaft 73 in a direction perpendicular to the switchingshaft 73. Thecoupling member 72 is held between astep 73b of the switchingshaft 73 and thestopper pin 77 to restrict axial movement of thecoupling member 72 relative to the switchingshaft 73. - The front surface of the
coupling member 72 includes arecess 78. Anelastic member 79 made of rubber or the like is arranged in therecess 78. As shown inFig. 4 , therecess 78 is a round hole having a larger diameter than the axial length of thestopper pin 77. Thus, thecoupling member 72 does not directly contact thestopper pin 77, and theelastic member 79 is arranged between the couplingmember 72 and thestopper pin 77. - As shown in
Figs. 2(a) and3(a) , the switchingshaft 73 is inserted through theinsertion hole 55 of thedrive shaft 6 so that the rear end of the switchingshaft 73 projects from thedrive shaft 6 toward the rear. The rear end of the switchingshaft 73 is fitted under pressure into the throughhole 32 of thesecond sun gear 21b. Thus, the switchingshaft 73 is fixed to thesecond sun gear 21b to be rotatable integrally with thesecond sun gear 21b and immovable in the axial direction relative to thesecond sun gear 21b. As a result, the switchingshaft 73 moves in the axial direction integrally with thesecond sun gear 21b (movable carrier 26) in cooperation with the movement of theswitch 28. - The operation of the impact rotation tool in the present embodiment will now be described.
- When using the impact rotation tool 1 as an impact driver, the
switch 28 is moved toward the rear to move thecoupling member 72 with the switchingshaft 73 toward the rear. As a result, thecoupling member 72 engages with the wall of only thedrive shaft hole 54, and the rotation tool 1 enters the impact mode. In the example shown inFig. 2(b) , during the impact mode, thecoupling member 72 is completely accommodated in thedrive shaft hole 54 and does not enter theanvil hole 58. In the impact mode, the impact torque generated by impact actions rotates theanvil 51 and tightens a screw or the like. - When using the impact rotation tool 1 as a drill driver, the
switch 28 is moved toward the front to move thecoupling member 72 with the switchingshaft 73 toward the front. As a result, thecoupling member 72 engages with the walls of both of thedrive shaft hole 54 and theanvil hole 58, and the rotation tool 1 enters the drill mode. As shown inFig. 3(b) , in the drill mode, the boundary between thedrive shaft 6 and theanvil 51 lies along thecoupling member 72. In the drill mode, the torque of themotor 5 is reduced in speed by thespeed reduction mechanisms drive shaft 6 in order to rotate theanvil 51 and tighten a screw or the like. - A regulated clearance in the axial direction is provided between the
drive shaft 6 and theanvil 51. Thus, thedrive shaft 6 moves toward theanvil 51 whenever an impact action is produced. Further, frictional force is produced where thecoupling member 72 contacts thedrive shaft 6. This pushes thecoupling member 72 against thestopper pin 77 in accordance with the frictional force. Due to errors in assembled components or the like, the frictional force produced between thedrive shaft 6 and thecoupling member 72 may strongly force a portion of thecoupling member 72 against the wall of thedrive shaft hole 54. - In this regard, the wall of the
drive shaft hole 54 in the present embodiment includes therelief 76. This decreases the area of thecoupling member 72 that contacts the wall of thedrive shaft hole 54 in comparison to when there is no relief. Thus, even when frictional force is produced between thedrive shaft 6 and thecoupling member 72 during an impact action due to errors in assembled components or the like, thecoupling member 72 is not pushed by a strong force. As a result, a large force is not applied to thestopper pin 77 by thecoupling member 72. Further, the force applied to thestopper pin 77 from thecoupling member 72 is absorbed by the elastic deformation of theelastic member 79, which is arranged between the couplingmember 72 and thestopper pin 77. In addition, the wall of thedrive shaft hole 54 includes theengagement portion 75. Thus, in comparison with when the diameter of thedrive shaft hole 54 is entirely larger in the axial direction than the outer diameter of thecoupling member 72, thecoupling member 72 is not rotated relative to thedrive shaft 6 in thedrive shaft hole 54. Thus, the edge of thecoupling member 72 does not contact the wall of thedrive shaft hole 54, and the application of excessive load to thedrive shaft 6 is suppressed. - The present embodiment has the advantages described below.
- (1) The wall of the
drive shaft hole 54 includes therelief 76 so that there is no contact with thecoupling member 72 during the impact mode. Thus, a large force is not applied by thecoupling member 72 to thestopper pin 77, and the life of thestopper pin 77 is prolonged. Further, the wall of thedrive shaft hole 54 includes theengagement portion 75 that is engaged with thecoupling member 72. This suppresses the application of excessive force to thedrive shaft 6 and prolongs the life of thedrive shaft 6. - (2) The
elastic member 79 is arranged between the couplingmember 72 and thestopper pin 77. Theelastic member 79 absorbs the force applied to thestopper pin 77 by thecoupling member 72. This decreases the force applied to thestopper pin 77 and further prolongs the life of thestopper pin 77. - In the above embodiment, a coil spring is used as the
hammer spring 53 serving as an urging member that urges thehammer 52 toward theanvil 51. Thehammer spring 53 may be a Belleville spring or the like. - In the above embodiment, the stopper does not have to be the
stopper pin 77 and may instead be a snap ring or the like. - In the above embodiment, the
elastic member 79, which is made of rubber or the like, may be arranged between the couplingmember 72 and thestopper pin 77. - In the above embodiment, the
relief 76 is an annular groove extending in the circumferential direction of thedrive shaft 6 and formed at the rear side of the inner circumferential surface of theengagement portion 75. Thus, the entire outer circumferential surface of the rear end of thecoupling member 72 does not contact therelief 76. Instead, for example, as shown inFig. 6 , therelief 76 may be formed by a linear groove extending in the axial direction. In the example shown inFig. 6 , a plurality of (six)reliefs 76 are formed at equal angular intervals in the circumferential direction. - In the above embodiment, the
drive shaft hole 54, theanvil hole 58, and thecoupling member 72 have hexagonal cross-sections. However, thedrive shaft hole 54, theanvil hole 58, and thecoupling member 72 may have any non-circular cross-section as long as the rotation of thecoupling member 72 may be transmitted to thedrive shaft hole 54 and theanvil hole 58. For example, the cross-section may be square, elliptic, or D-shaped. - In the above embodiment, the rotational power source is not limited to the
motor 5 and may be, for example, a hydraulic or pneumatic rotational power source. - The present examples and embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein.
Claims (6)
- An impact rotation tool (1) including:a drive shaft (6) rotated and driven by a rotational power source (5), wherein the drive shaft (6) includes a drive shaft hole (54);an anvil (51) that is coaxial with the drive shaft (6) and rotatable relative to the drive shaft (6), wherein the anvil (51) includes an anvil hole (58);a hammer (52) rotated by the drive shaft (6) and engaged with the anvil (51), wherein the hammer (52) is coupled to the drive shaft (6) so that the hammer (52) moves away from the anvil (51) in an axial direction of the drive shaft (6) when the hammer (52) rotates relative to the drive shaft (6);an urging member (53) that urges the hammer (52) toward the anvil (51); anda switching mechanism (71) that switches the impact rotation tool (1) between an impact mode that impacts the anvil (51) with the hammer (52) and a drill mode that integrally rotates the drive shaft (6) and the anvil (51), wherein the switching mechanism (71) includesa coupling member (72) movable between a position where the coupling member (72) is engaged with a wall of only one of the drive shaft hole (54) and the anvil hole (58) and a position where the coupling member (72) is engaged with the walls of both of the drive shaft hole (54) and the anvil hole (58),a switching shaft (73) that supports the coupling member (72) to be rotatable and moves the coupling member (72) in the axial direction, anda stopper (77) that restricts axial movement of the coupling member (72) relative to the switching shaft (73); andwherein the switching shaft (73) moves the coupling member (72) to the position where the coupling member (72) is engaged with the wall of only the drive shaft hole (54) to switch to the impact mode, andwherein the switching shaft (73) moves the coupling member (72) to the position where the coupling member (72) is engaged with the walls of both of the drive shaft hole (54) and the anvil hole (58) to switch to the drill mode, and wherein the wall of the drive shaft hole (54) includesan engagement portion (75) engaged with the coupling member (72) in the impact mode, and the impact rotation tool (1) being characterised in that the wall of the drive shaft hole (54) further includes a relief (76) formed so as not to contact an outer circumferential surface of the coupling member (72) in the impact mode.
- The impact rotation tool (1) according to claim 1, further including an elastic member (79) arranged between the coupling member (72) and the stopper (77).
- The impact rotation tool (1) according to claim 1 or 2, wherein the relief (76) of the drive shaft hole (54) is formed to form a clearance between the coupling member (72) and the drive shaft (6).
- The impact rotation tool (1) according to any one of the preceding claims, wherein the coupling member (72) includes a distal portion and a basal portion;
in the drill mode, the distal portion of the coupling member (72) engages with the inner surface of the anvil hole (58), and the basal portion of the coupling member (72) is engaged with the engagement portion (75) of the drive shaft hole (54), and the basal portion of the coupling member (72) is engaged with the engagement portion (75) of the drive shaft hole (54); and
in the impact mode, the distal portion of the coupling member (72) is engaged with the engagement portion (75) of the drive shaft hole (54), and the basal portion of the coupling member (72) is separated from the relief (76) of the drive shaft hole (54) in a radially inner direction. - The impact rotation tool (1) according to any one of the preceding claims, wherein the engagement portion (75) includes an inner diameter substantially equal to an outer diameter of the coupling member (72), and
the relief (76) has an inner diameter that is substantially larger than the outer diameter of the coupling member (72). - The impact rotation tool (1) according to any one of the preceding claims, wherein the drive shaft (6) includes a distal end supported to be rotatable by the anvil (51), and
the relief (76) is located in the drive shaft hole (54) at a position that is farther from the distal end of the drive shaft (6) than the engagement portion (75).
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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JP2012216027A JP5963050B2 (en) | 2012-09-28 | 2012-09-28 | Impact rotary tool |
Publications (3)
Publication Number | Publication Date |
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EP2712708A2 EP2712708A2 (en) | 2014-04-02 |
EP2712708A3 EP2712708A3 (en) | 2018-03-21 |
EP2712708B1 true EP2712708B1 (en) | 2019-02-06 |
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Family Applications (1)
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EP13184680.0A Active EP2712708B1 (en) | 2012-09-28 | 2013-09-17 | Impact rotation tool |
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EP (1) | EP2712708B1 (en) |
JP (1) | JP5963050B2 (en) |
CN (1) | CN103707253B (en) |
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US11565394B2 (en) * | 2019-10-28 | 2023-01-31 | Snap-On Incorporated | Double reduction gear train |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3952814A (en) * | 1975-03-14 | 1976-04-27 | Mikhail Lvovich Gelfand | Impact wrench |
JP3372345B2 (en) * | 1993-05-26 | 2003-02-04 | 松下電工株式会社 | Impact rotary tool |
CN1145843A (en) * | 1996-07-18 | 1997-03-26 | 丁心河 | Automatic 12V electrical turning machine for mounting and dismounting tyre of heavy truck |
JP3911905B2 (en) * | 1999-04-30 | 2007-05-09 | 松下電工株式会社 | Impact rotary tool |
JP4468786B2 (en) * | 2004-10-28 | 2010-05-26 | 株式会社マキタ | Impact tools |
US20060237205A1 (en) * | 2005-04-21 | 2006-10-26 | Eastway Fair Company Limited | Mode selector mechanism for an impact driver |
US7410007B2 (en) * | 2005-09-13 | 2008-08-12 | Eastway Fair Company Limited | Impact rotary tool with drill mode |
EP2815850B1 (en) * | 2007-02-23 | 2016-02-03 | Robert Bosch Gmbh | Rotary power tool operable in either an impact mode or a drill mode |
JP5382291B2 (en) * | 2008-05-08 | 2014-01-08 | 日立工機株式会社 | Oil pulse tool |
US9193053B2 (en) * | 2008-09-25 | 2015-11-24 | Black & Decker Inc. | Hybrid impact tool |
JP4636188B2 (en) * | 2009-01-27 | 2011-02-23 | パナソニック電工株式会社 | Switching operation device |
JP4674640B2 (en) * | 2009-01-27 | 2011-04-20 | パナソニック電工株式会社 | Impact rotary tool |
-
2012
- 2012-09-28 JP JP2012216027A patent/JP5963050B2/en active Active
-
2013
- 2013-09-17 EP EP13184680.0A patent/EP2712708B1/en active Active
- 2013-09-25 CN CN201310445723.8A patent/CN103707253B/en active Active
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Also Published As
Publication number | Publication date |
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EP2712708A3 (en) | 2018-03-21 |
CN103707253A (en) | 2014-04-09 |
EP2712708A2 (en) | 2014-04-02 |
CN103707253B (en) | 2016-01-27 |
JP5963050B2 (en) | 2016-08-03 |
JP2014069262A (en) | 2014-04-21 |
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