Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25D—PERCUSSIVE TOOLS
  • B25D17/00—Details of, or accessories for, portable power-driven percussive tools
  • B25D17/08—Means for retaining and guiding the tool bit, e.g. chucks allowing axial oscillation of the tool bit
  • B25D17/084—Rotating chucks or sockets
  • B25D17/088—Rotating chucks or sockets with radial movable locking elements co-operating with bit shafts specially adapted therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25D—PERCUSSIVE TOOLS
  • B25D2217/00—Details of, or accessories for, portable power-driven percussive tools
  • B25D2217/003—Details relating to chucks with radially movable locking elements
  • B25D2217/0038—Locking members of special shape
  • B25D2217/0042—Ball-shaped locking members
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25D—PERCUSSIVE TOOLS
  • B25D2222/00—Materials of the tool or the workpiece
  • B25D2222/21—Metals
  • B25D2222/42—Steel

Definitions

• the present invention relates to a striking tool that performs a predetermined processing operation on a workpiece by striking a tool bit in a major axis direction.
• the hammer bit In an impact tool such as a hammer or a hammer drill, the hammer bit is held so that its shaft portion can be moved in the major axis direction by a tool holder. Therefore, a small gap is formed between the inner wall surface of the bit holding hole of the tool holder and the outer surface of the shaft portion of the hammer bit inserted into the bit holding hole to allow the shaft portion to be inserted. Yes. For this reason, there is a hammer work for workpieces such as concrete! /, During the hammer drill work! /, And the concrete dust generated by the work adheres to the outer surface of the shaft portion of the hammer bit. Enter the gap.
• Patent Document 1 a hitting tool in which a tool holder is subjected to wear is disclosed in WO 02/20224 (Patent Document 1).
• the wear of the inner wall surface of the bit holding hole is reduced by press-fitting a sleeve of a separate member formed of a material harder than the main body of the tool holder. .
• the hammer bit inserted into the bit holding hole of the tool holder is configured to be prevented from being pulled out by a steel ball arranged in the tool holder. Therefore, when the hammer bit strikes the tool holder, an axial impact force acts on the tool holder via the steel ball. For this reason, in the technique described in the above publication, in which the full length of the bit holding hole into which the shaft portion of the hammer bit is inserted is formed with a hard sleeve, an impact force acts on the sleeve. However, since a sleeve made of a hard material is hard, it may cause cracking with an impact force.
• the sleeve is formed with a long hole penetrating in the radial direction for placing the steel ball.
• the sleeve is hard, there is a problem that drilling by machining is difficult. That is, the conventional impact tool described in the publication still has room for improvement in terms of durability or workability.
• Patent Document 1 WO International Publication No. 02/20224
• An object of the present invention is to provide a technique that contributes to improving the durability and workability of a tool holder that holds a tool bit in an impact tool in view of the force and the point.
• a tool holder having a bit holding hole and a tool bit that is inserted into the bit holding hole and is held so as to be movable in the major axis direction, and the tool bit is at least in the major axis direction.
• a striking tool for performing a predetermined processing operation on the workpiece by performing a striking operation is configured.
• “at least a long-axis hitting operation” corresponds to a mode in which the tool bit is driven only by the hitting operation and a mode in which the tool bit is driven by a combination of the hitting operation and the rotation operation. .
• the tool holder has a bit holding region that contacts the outer surface of the tool bit inserted into the bit holding hole and holds the tool bit so as to be movable in the major axis direction.
• the bit holding area has a first holding area, a second holding area, and a third holding area in this order from the bit hole entrance side to the back side of the bit holding hole.
• the first holding area is provided as an area for holding the tool bit inserted into the bit holding hole while allowing relative movement in the major axis direction.
• the second holding area is provided as an arrangement area of a retaining member for preventing the tool bit from coming out of the bit holding hole by engaging with the tool bit.
• the third holding area is provided as an area for holding the insertion direction end of the tool bit inserted into the bit holding hole while allowing relative movement in the major axis direction.
• the hardness of the first holding region is set higher than the hardness of the second holding region.
• the “hardness of the first holding region” in the present invention is preferably set to Rockwell C-scale hardness (HRC) of 60 or more, and the material of the first holding region is alloy tool steel. Materials (SKD), high-speed tool steel (SKH), high-carbon chromium bearing steel (SUJ), etc. are preferably used.
• the place where dust generated by the machining operation is likely to enter that is, the bit heel entrance side is in an environment where wear is most likely to occur.
• the hardness of the first holding area on the side of the heel entrance where wear is most likely to occur is set higher than the hardness of the second holding area.
• the wear resistance of the holding region can be increased. This can reduce the wear of the first holding region and improve the durability.
• the wear of the bit holding area causes the tool bit to sway, and, for example, in the case of a hammer drill, the tool holder is formed on the tool holder to transmit the rotational movement of the tool holder to the tool bit.
• the wear of the tool holding bit is suppressed by reducing the wear of the first holding region, and as a result, the wear of the torque transmission protrusion is also reduced.
• the areas other than the first holding area are preferably set to the conventional hardness.
• the hardness of the second holding region in which the stopper member is disposed is preferably set to the conventional hardness, so that the hardness is too high due to the impact force applied during the impact operation of the tool bit. Therefore, the crack which arises because of can be prevented.
• the hardness of the second holding region is preferably set to the conventional hardness. Therefore, machinability is not impaired.
• the hardness of the third holding region is set to be higher than the hardness of the second holding region.
• “the hardness of the third holding region” is set to be equal to the hardness of the first holding region.
• the hardness of the portion that receives the force in the crossing direction is set to be higher than the hardness of the second holding region.
• Durability can be improved by reducing wear on the first holding region and the third holding region.
• the effect of preventing the tool bit from swinging is further improved.
• the impact tool is configured as a hammer drill, torque transmission is achieved.
• the wear of the projections can be effectively reduced.
• At least a first holding region force of the first holding region and the third holding region has a hardness higher than the hardness of the second holding region. It is formed by members.
• the “separate member” in the present invention typically corresponds to a ring-shaped member.
• “formed” in the present invention typically means a mode in which a ring-shaped member is press-fitted into a cylindrical hole of a tool holder, and a mode other than force press-fitting, for example, a screw is used to fix the member. Or the aspect fixed by welding etc. is included suitably.
• the first holding region is formed by a separate member, it is possible to easily manufacture a bit holding hole having a holding region with different hardness in the axial direction. Can be improved.
• the retaining member disposed in the second holding region moves in the inner diameter direction of the bit holding hole and engages with the tool bit to remove the tool bit.
• the tool bit is configured to be released and moved in the outer diameter direction of the bit holding hole to release the tool bit.
• the second holding region is formed with an opening for disposing the retaining member so as to be movable in the radial direction.
• the opening in which the retaining member is disposed is provided in the second holding region whose hardness is lower than the hardness of the first holding region. For this reason, when the opening is formed by, for example, machining, the machining can be easily performed, and the workability can be improved.
• FIG. 1 is a sectional view showing the overall configuration of the electric hammer drill according to the present embodiment.
• the hammer drill 101 according to the present embodiment generally has a main body 103 that forms an outline of the hammer drill 101, and a tool holder 137 in the tip region (left side in the drawing) of the main body 103.
• the main body is composed of a non-mabit 119 which is detachably attached via a grip and a grip 109 which is gripped by an operator connected to the opposite side of the hammer bit 119 of the main body 103.
• the hammer bit 119 is mounted so as to be movable relative to the tool holder 137 in the long axis direction and to rotate together with the tool holder 137 in the circumferential direction.
• This hammer bit 119 corresponds to a “tool bit” in the present invention.
• the Nomabit 119 side is the front and the Drip 109 side is the back!
• the main body 103 includes a motor housing 105 that houses a drive motor 111, and a gear housing 107 that houses a motion conversion mechanism 113, a power transmission mechanism 114, and a striking element 115.
• 105 and the gear housing 107 are joined to each other by screws or the like (not shown).
• the rotational output of the drive motor 111 is appropriately converted into a linear motion by the motion conversion mechanism 113 and then transmitted to the striking element 115, and the hammer bit 119 passes through the striking element 115 in the longitudinal direction (Fig. 1 To generate an impact force in the horizontal direction.
• the rotational output of the drive motor 111 is appropriately decelerated by the power transmission mechanism 114 and then transmitted as a rotational force to the hammer bit 119, and the hammer bit 119 is rotated in the circumferential direction.
• the driving motor 111 is energized and driven by pulling a trigger 117 disposed on the grip 109.
• the motion conversion mechanism 113 is provided at the tip (front end) of the armature shaft 112 of the drive motor 111 and is driven to rotate in a vertical plane.
• the intermediate shaft 125 is in the long axis direction of the hammer bit 119.
• the outer peripheral surface of the rotating body 127 that is arranged in parallel (horizontal) and is attached to the intermediate shaft 125 is formed to be inclined at a predetermined inclination angle with respect to the axis of the intermediate shaft 125.
• the swash plate 129 is attached to the inclined outer peripheral surface of the rotating body 127 through a ball bearing 126 so as to be relatively rotatable, and is swung in the axial direction of the hammer bit 119 as the rotating body 127 rotates.
• the swash plate 129 has a swing rod 128 that protrudes integrally upward (radially), and the swing rod 128 passes through the rear end of the cylindrical piston 141 and the connecting shaft 124. And are connected so as to be relatively rotatable.
• the cylindrical piston 141 is slidably disposed in a sleeve 135 disposed in the gear housing 107, and the rear end portion of the cylindrical hole is closed.
• the power transmission mechanism 114 is engaged with the first transmission gear 131 that is rotationally driven in the vertical plane from the drive motor 111 via the drive gear 121 and the intermediate shaft 125, and the first transmission gear 131.
• the second transmission gear 133, the sleeve 135 rotated together with the second transmission gear 133, and the tool holder 137 rotated in the vertical plane together with the sleeve 135 are mainly configured.
• the striking element 115 slides on a cylindrical piston 141, a striker 143 slidably disposed on the inner wall of the cylindrical hole of the cylindrical piston 141, and a tool holder 137.
• the impact bolt 145 that transmits the kinetic energy of the striker 143 to the hammer bit 119 is mainly configured.
• the rotation output causes the drive gear 121 to rotate within the lead confrontation. Operate. Then, the rotating body 127 is rotated in the vertical plane via the driven gear 12 3 and the intermediate shaft 125 which are engaged with and engaged with the drive gear 121, whereby the swash plate 129 and the swing rod 128 are moved. Swings in the axial direction of the hammer bit 119.
• the cylindrical piston 141 is slid linearly by the swing of the swing rod 128, and the striker 143 is moved to the cylinder by the air pressure change in the air chamber 141a of the cylindrical piston 141, that is, the action of the air panel.
• the linear piston 141 moves linearly.
• the striker 143 collides with the impact Bonoret 145 and transmits the kinetic energy to the hammer bit 119.
• the first transmission gear 131 when the first transmission gear 131 is rotated together with the intermediate shaft 125, the first transmission gear 131 The sleeve 135 is rotated in the vertical plane via the second transmission gear 133 engaged with each other, and the tool holder 137 and the hammer bit 119 held by the tool holder 137 are formed into a body shape together with the sleeve 135. It is rotated.
• the hammer bit 119 performs the hammering operation in the axial direction and the drilling operation in the circumferential direction to perform the drilling work (mainly drilling work) on the workpiece (concrete).
• the hammer drill 101 is not limited to the operation mode in the hammer drill mode in which the hammer bit 119 performs the hammer operation and the circumferential drill operation, and the hammer bit 119 performs only the drill operation. Force to be switched to work mode in drill mode The switching mechanism in this mode is not directly related to the present invention, and thus the description thereof is omitted.
• the bit holding mechanism 151 is configured to remove a turret renoder 137 having a bit holding hole 137a having a circular cross section into which the shaft portion 119a of the hammer bit 119 is removably inserted, and the hammer bit 119 inserted into the bit holding hole 137a. It is mainly composed of a plurality of steel balls (steel balls) 153 as locking members that restrict or allow extraction, and a tool sleeve 155 that switches the steel balls 153 between a bit extraction restriction position and a bit extraction allowable position.
• steel balls steel balls
• the tool holder 137 has a bit holding portion 137A in which a bit holding hole 137a is formed penetrating in the long axis direction, and an impact bolt accommodating portion 137B in which a space for accommodating the impact bolt 145 is formed.
• An impact bolt housing part 137B is provided on the body on the rear side in the long axis direction of the holding part 137A.
• the impact bolt accommodating portion 137B is connected to the sleeve 135 described above, whereby the tool holder 137 rotates with the sleeve 135.
• the tool holder 137 and the sleeve 135 may be formed integrally.
• the bit holding portion 137A of the tool holder 137 corresponds to the “bit holding area” in the present invention.
• the bit holding hole 137a is opened at the tip as a bit rod inlet, and is opened in the space of the rear end force S impact bolt accommodating portion 137B.
• the bit holder 137A of the tool holder 137 is formed with a plurality of long holes 137b penetrating in the radial direction.
• the plurality of long holes 137b extend by a predetermined length in the major axis direction of the bit holding portion 137A and are arranged around the bit holding portion 137A.
• the steel balls 153 are respectively disposed in the long holes 137b.
• the steel ball 153 is movable in the long axis direction in the long hole 137b and can be moved (displaced) in the radial direction of the bit holding portion 137A.
• the long hole 137b corresponds to the “opening” in the present invention.
• the tool sleeve 155 is arranged on the outside of the bit holding portion 137A so as to be movable in the bit long axis direction, and on the inside thereof, a regulating ring 157 for regulating the displacement of the steel ball 153 in the outer diameter direction is arranged, Further, a regulating plate 159 is disposed on the rear side of the regulating ring 157.
• the restriction plate 159 can move in the longitudinal direction of the tool sleeve 155 with respect to the tool sleeve 155, and is pressed against the rear surface of the restriction ring 157 by the biasing panel 161 disposed between the bit holding part 137A. It has been.
• the biasing force of the biasing spring 161 acts as a force that pushes the tool sleeve 155 forward. For this reason, the tool sleeve 155 is normally held at a position where the front end abuts against the cap 163 attached to the front end of the bit holding portion 137A, that is, at the bit extraction restriction position.
• the locking groove 119b provided on the outer surface of the part is engaged to prevent it from coming off.
• the locking groove 119b of the hammer bit 119 extends by a predetermined length in the long axis direction.
• a plurality of protrusions 137c serving as torque transmitting portions protruding in the radial direction are provided at predetermined intervals in the circumferential direction on the inner surface of the bit holding hole 137a of the bit holding portion 137A.
• the torque transmission projection 137c extends a predetermined length in the major axis direction of the bit holding portion 137A, and is formed on the outer surface of the shaft portion 119a of the hammer bit 119 inserted into the bit holding hole 137a. It fits into (engages with) the torque transmission groove 119c (see FIG. 3), and in this state, the rotational force of the bit holding portion 137A is transmitted to the hammer bit 119.
• the torque transmission groove 119c is open at the rear end of the shaft portion 119a, and the circumferential direction when the hammer bit 119 is inserted into the bit holding hole 137a. Used for positioning.
• the hammer bit 119 is held by the bit holding portion 137A of the tool holder 137 in a state where movement in the major axis direction is allowed by the bit holding mechanism 151.
• the holding rings 165 and 167 are press-fitted into the bit holder inlet side of the bit holder hole 137a and the bit holder insertion rear side, that is, the impact bolt housing part 137B side, respectively. Talk to me.
• Both retaining rings 165, 167 Also, material harder than bit retaining force 137A, for example, Rockwell C scale hardness (HRC) 60 or more alloy tool steel (SKD), high speed tool steel (SKH) It is made of high carbon chromium bearing steel (SUJ), etc.
• the retaining ring 165 on the inlet side of the bit hole holds the hammer bit 119 inserted into the bit holding hole 137a while allowing relative movement in the major axis direction.
• the retaining ring 167 A on the inner side of the bit insertion direction holds the end of the hammer bit 119 inserted into the bit holding hole 137a while allowing relative movement in the major axis direction.
• the area sandwiched between the holding rings 165 and 167 is a mechanism for preventing the hammer bit 119 inserted into the bit holding hole 137a from being removed, and the rotational driving force of the tool holder 137 to the hammer bit 119.
• the transmission mechanism is arranged It provided as an area for.
• the bit wall entrance side inner wall surface 165a and the inner wall surface 167a on the inner side of the bit holding hole 137a that contacts the outer surface of the shaft portion 119a of the hammer bit 119. Is set higher than the hardness of the intermediate inner wall surface 166a between the bit wall entrance side inner wall surface 165a and the inner wall surface 167a.
• the bit wall inlet side inner wall surface 165a corresponds to the “first holding region” in the present invention
• the back side inner wall surface 167a corresponds to the “third holding region” in the present invention, and the intermediate inner wall surface 166a.
• the long hole 137b and the torque transmission projection 137c for placing the steel ball 153 as the retaining member described above are sandwiched between the holding rings 165 and 167. Provided on the bit holding portion 137A constituting the intermediate inner wall surface 166a.
• the hammer drill 101 is configured as described above.
• Hammer bit 1 The inner wall surface of the bit holding hole 137a into which the shaft portion 119a is inserted is placed in an environment where the bit wall entrance side inner wall surface 165a where dust generated by machining operations easily enters is most likely to be worn. .
• the bit wall inlet side inner wall surface 165a which is likely to be worn, is hardened (Rockwell C scale hardness (HR C) of 60 or more).
• HR C Rockwell C scale hardness
• the hammer bit 119 When the hammer bit 119 performs a machining operation by hitting the hammer bit 119, the hammer bit 119 includes not only a force in the long axis direction but also a radial direction intersecting the long axis direction as a reaction force from the workpiece. External force including components also acts.
• the inner wall surface of the bit holding hole 137a supports the force in the intersecting direction acting on the hammer bit 119 mainly by the inner wall surface 165a and the inner wall surface 167a on the bit side.
• the portion receiving the force in the crossing direction that is, the inner wall surfaces 165a, 167a on the bit heel entrance side and the back side are formed by the retaining rings 16 5, 167 having high hardness, It is possible to enhance the durability of the inner wall surfaces 165a and 167a on the bit hole entrance side and the rear side, which are load application sites, and to rationally reduce the wear of the inner wall surfaces 165a and 167a.
• the wear of the inner wall surface of the bit holding hole 137a causes the hammer bit 119 to sway, and in particular, in the case of the hammer drill 101, the rotational force of the tool holder 137 is transmitted to the hammer bit 119.
• the torque transmission protrusion 1 37c formed on the tool holder 137 is worn, and as a result, the drilling operation due to the swing of the hammer bit 119 becomes difficult.
• the wear force S of the inner wall surfaces 165a, 167a on the bit rod inlet side and the inner wall surface 165a on the inner side of the bit rod is reduced with respect to the inner wall surface of the bit holding hole 137a. This reduces the wear on the torque transmission projection 137c.
• the bit holding portion 137A constituting the intermediate inner wall surface 166a of the inner wall surface of the bit holding hole 137a can be set to the conventional hardness, the above-described cracking problem Problems such as deterioration of workability are solved. Further, in the present embodiment, since the holding rings 165 and 167 having a hardness higher than the hardness of the bit holding portion 137A are respectively press-fitted into the heel entrance side and the back side of the bit holding hole 137a, the hardness differs. The bit holding hole 137a having the inner wall surface can be easily manufactured.
• the holding ring 165 is provided only on the inlet side of the bit bit hole, and the holding ring 165 is provided only on the inlet side and the inner side of the bit holding hole 137a. You can change it.
• the holding rings 165 and 167 may be fixed by means other than press fitting, such as welding or screws.
• the present embodiment may be applied to an electric hammer in which the force hammer bit 119 described using the electric hammer drill performs only a hammer operation as an example of a hitting tool.
• FIG. 1 is a cross-sectional view showing an overall configuration of an electric hammer drill according to the present embodiment.
• FIG. 2 is a cross-sectional view mainly showing a bit retaining portion with respect to the configuration of the holding mechanism portion of the hammer bit.
• FIG. 3 is a cross-sectional view mainly showing a torque transmission part with respect to the configuration of the holding mechanism part of the hammer bit.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Percussive Tools And Related Accessories (AREA)
• Electrophonic Musical Instruments (AREA)

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Citations (5)

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• 2006
  • 2006-11-22 JP JP2006316087A patent/JP2008126378A/ja active Pending
• 2007
  • 2007-11-21 WO PCT/JP2007/072594 patent/WO2008062851A1/ja active Application Filing
  • 2007-11-21 AT AT07832324T patent/ATE543613T1/de active
  • 2007-11-21 EP EP07832324A patent/EP2085190B1/en not_active Not-in-force

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