JP7365197B2 - reciprocating tool - Google Patents

Description

The present invention relates to a reciprocating tool configured to linearly drive a tip tool.

A reciprocating tool is known that is configured to linearly drive a tip tool using a reciprocating member that reciprocates linearly along a predetermined drive axis. In reciprocating tools, relatively large vibrations occur in the axial direction of the drive shaft. Therefore, reciprocating tools equipped with a vibration damping mechanism for reducing vibrations are known. For example, Patent Document 1 discloses an electric hammer equipped with a dynamic vibration absorber including a weight and springs arranged on both sides of the weight in the axial direction of a drive shaft. The weight is formed in a cylindrical shape and is arranged around a cylinder that accommodates the piston, that is, around the drive shaft, in the internal space of the barrel portion.

Japanese Patent Application Publication No. 2015-182167

In the electric hammer disclosed in Patent Document 1, with the arrangement as described above, vibration in the axial direction of the drive shaft can be effectively suppressed. However, depending on the structure of the reciprocating tool, it may be difficult to secure space for arranging the vibration damping mechanism around the drive shaft.

In view of this situation, an object of the present invention is to provide a rational arrangement of a vibration damping mechanism in a reciprocating tool.

According to one aspect of the present invention, a reciprocating tool including a motor, a drive mechanism, a main body housing, a movable part, and a vibration damping mechanism is provided. The motor has an output shaft. The drive mechanism includes a reciprocating member configured to reciprocate in a first direction along the drive shaft by power of the motor, and linearly drives the tip tool as the reciprocating member reciprocates. It is configured as follows. The main body housing houses the motor and the drive mechanism. The movable part includes a grip part that is gripped by a user, and is connected to the main body housing via a first elastic member and a second elastic member. The movable part is movable relative to the main body housing in the extending direction of the drive shaft between an initial position and a proximal position closer to the main body housing than the initial position. The vibration damping mechanism is provided in the main body housing. The damping mechanism includes at least one weight configured to move in a direction opposite to the reciprocating member as the reciprocating member reciprocates.

Moreover, the center of gravity of at least one weight is located at a position shifted from the drive shaft in a second direction perpendicular to the drive shaft. The first elastic member is disposed closer to the center of gravity than the second elastic member in the second direction. In other words, the distance between the first elastic member and the center of gravity in the second direction is shorter than the distance between the second elastic member and the center of gravity in the second direction. Furthermore, the load on the first elastic member when the movable part is placed in the close position is smaller than the load on the second elastic member. In other words, the first elastic member has a smaller urging force that urges the main body housing and the movable part away from each other than the second elastic member.

In the reciprocating tool of this aspect, the center of gravity of at least one weight is offset from the drive shaft in the second direction. In such an arrangement, the at least one weight can satisfactorily reduce vibrations generated in the main body housing in the first direction due to the reciprocating movement of the reciprocating member, while vibrations tend to occur in the second direction. It is considered that the vibration in the second direction is particularly susceptible to the impact when the reciprocating member moves toward the tip tool and at least one weight moves in the opposite direction in the first direction. On the other hand, in the reciprocating tool of this aspect, the above-mentioned load settings make the first elastic member more elastically deformable, and by effectively absorbing this impact, the vibration in the second direction is applied to the movable part. transmission can be effectively suppressed. Therefore, even if it is difficult to secure a space for arranging the vibration damping mechanism around the drive shaft, it is possible to realize a rational arrangement of the vibration damping mechanism.

In one aspect of the invention, the grip portion may extend in the second direction. In this case, since vibration transmission in the second direction to the gripping portion is suppressed, gripping stability can be maintained favorably.

In one aspect of the present invention, in the second direction, the first elastic member may be disposed on the same side as the center of gravity with respect to the drive shaft, and the second elastic member may be disposed on the opposite side. In this case, it is possible to more effectively suppress vibrations in the second direction from being transmitted to the movable part.

In one aspect of the invention, part of the motor may be located on the drive shaft. The rotation axis of the output shaft may intersect the drive shaft. Furthermore, in this aspect, the gripping part may be arranged on the opposite side of the drive mechanism with respect to the motor in the first direction so that a part of the gripping part is located on the drive shaft.

In one aspect of the invention, the drive mechanism may include a motion conversion mechanism configured to convert rotational motion of the output shaft into linear motion and reciprocate the reciprocating member. At least a portion of the vibration damping mechanism may be disposed on the opposite side of at least a portion of the motion conversion mechanism across the drive shaft in the second direction. According to this aspect, a good weight balance is achieved by arranging at least part of the motion conversion mechanism and at least part of the vibration damping mechanism, which are heavy objects, with the drive shaft in between in the second direction. becomes possible.

In one aspect of the invention, the vibration damping mechanism may include at least one dynamic vibration absorber. Furthermore, in this aspect, the drive mechanism may include a motion conversion mechanism configured to convert the rotational motion of the output shaft into linear motion and cause the reciprocating member to reciprocate. The weight may be vibrated by driving the motion conversion mechanism. In this case, the weight can be actively vibrated when the motion conversion mechanism is driven. Thereby, vibrations can be absorbed more effectively.

In one aspect of the present invention, the at least one dynamic vibration reducer may include a pair of dynamic vibration absorbers arranged side by side in a third direction orthogonal to the first direction and the second direction. In this case, compared to the case where one dynamic vibration absorber is provided, each dynamic vibration absorber can be made smaller, and the overall arrangement can be more compact.

In one aspect of the present invention, the first elastic member and the second elastic member may be springs having the same configuration, but may be attached to the main body housing and the movable portion in different states. In this case, by using the same spring, the loads of the first elastic member and the second elastic member can be easily made different when the movable parts are arranged in close positions. Note that instead of this embodiment, elastic members having different spring constants may be used as the first elastic member and the second elastic member.

FIG. 3 is a left side view of the electric hammer. It is a perspective view of an electric hammer. It is a sectional view of an electric hammer. FIG. 3 is a perspective view of the rear end of the electric hammer with the handle removed (however, electric wires are not shown). FIG. 3 is a partial cross-sectional view of the rear end of the electric hammer, and is an explanatory diagram of an elastic connection structure between the main body housing and the movable housing. It is an explanatory view showing an electric hammer when a movable housing is in an initial position. It is an explanatory view showing an electric hammer when a movable housing is in a close position. FIG. 3 is a sectional view of the rear end of the electric hammer. FIG. 2 is a perspective view of the rear end of the electric hammer with the handle and rear cover removed (however, electric wires are not shown). FIG. 3 is a rear view of the rear end of the electric hammer with the handle, rear cover, and controller case cover removed. FIG. 3 is a bottom view of the electric hammer with the lower part of the outer housing section removed. FIG. 12 is a sectional view taken along line XII-XII in FIG. 11 (with the lower portion attached).

Hereinafter, an electric hammer 101 according to an embodiment will be described with reference to the drawings. The electric hammer (hereinafter simply referred to as a hammer) 101 is an electric tool configured to linearly drive the tip tool 91 along a predetermined drive axis A1 (hereinafter referred to as a hammer operation), Used for chiseling and scraping work.

First, a schematic configuration of the hammer 101 will be described. As shown in FIGS. 1 to 3, the outer shell of the hammer 101 is mainly formed by the housing 10. Housing 10 extends along drive axis A1.

A cylindrical tool holder 112 is fixedly connected to one end of the housing 10 in the axial direction of the drive shaft A1 (hereinafter simply referred to as the drive shaft direction). The tool holder 112 is arranged coaxially with the drive shaft A1 and is configured to removably hold the tip tool 91. The tip tool 91 is inserted into the bit insertion hole at the front end of the tool holder 112 so that its long axis coincides with the drive axis A1, allowing movement in the axial direction with respect to the tool holder 112, and restricting rotation around the axis. is maintained in the same state.

The other end of the housing 10 in the drive shaft direction is provided with an elongated grip portion 181 that is gripped by a user. The grip portion 181 extends in a direction substantially perpendicular to the drive shaft A1, and a portion thereof is disposed on the drive shaft A1. The grip portion 181 is provided with a trigger 182 that can be pressed by the user. Note that the trigger 182 is provided at one end of the grip portion 181 in the longitudinal direction. When the user presses the trigger 182, the tip tool 91 is linearly driven along the drive shaft A1.

The detailed configuration of the hammer 101 will be described below. In the following description, for convenience, the drive shaft direction (long axis direction of the housing 10) is defined as the front-rear direction of the hammer 101. In the front-back direction, one end side where the tool holder 112 is arranged is defined as the front side of the hammer 101, and the opposite side (the side where the grip part 181 is arranged) is defined as the rear side. Further, the long axis direction of the grip portion 181 is defined as the vertical direction of the hammer 101. In the vertical direction, one end side where the trigger 182 is arranged is defined as an upper side, and the opposite side is defined as a lower side. Further, a direction perpendicular to the front-rear direction and the up-down direction is defined as the left-right direction.

First, the configuration of the housing 10 will be explained. The housing 10 of this embodiment is configured as a so-called vibration-proof housing, and includes a main body housing 11 and a movable housing 15 elastically connected to the main body housing 11 so as to be movable relative to the main body housing 11.

As shown in FIG. 3, the main body housing 11 is a housing that mainly houses the motor 2 and the drive mechanism 3. As shown in FIG. The front half of the main body housing 11 is formed into a cylindrical shape. This cylindrical front half portion is called a barrel portion 111. A tool holder 112 is fixed to the front end of the barrel portion 111 with a screw. The rear half of the main body housing 11 other than the barrel portion 111 is formed into a generally rectangular box shape. The latter half of this rectangular box shape is referred to as a main body portion 113.

As shown in FIGS. 3 and 4, a controller case 13 and a rear cover 12 are fixed to a rear wall 114 of the main body housing 11 (main body portion 113). The controller case 13 is an elongated rectangular box-like body. The controller case 13 is arranged to extend in the vertical direction and is fixed to the rear wall 114 of the main body part 113 with screws. The rear cover 12 has a U-shaped cross section. The rear cover 12 is fixed to the controller case 13 with screws, with both ends of the rear cover 12 abutting the left and right ends of a vertically central region (an exposed region 117 to be described later) of the rear wall 114. The rear cover 12 covers a part of the controller case 13 (specifically, a first housing space 131, which will be described later). In this way, the controller case 13 and the rear cover 12 are integrated into the main body housing 11.

As shown in FIGS. 1 to 4, the movable housing 15 is a housing that covers a part of the main housing 11 and has a grip portion 181. More specifically, the movable housing 15 includes an outer housing portion 16, a barrel cover 17, and a handle portion 18.

The outer housing part 16 includes an upper part 161 of the main body housing 11 that covers the upper surface and the upper parts of the left and right side surfaces of the main body part 113, and a lower part 163 that covers the lower surface and the lower parts of the left and right sides of the main body part 113. The upper part 161 and the lower part 163 are both covers having a U-shaped cross section, and have approximately the same length as the main body part 113 in the front-rear direction. The left and right lower ends of the upper portion 161 and the left and right upper ends of the lower portion 163 are spaced apart from each other. That is, a gap is provided between the upper portion 161 and the lower portion 163 in the vertical direction.

With this arrangement, the central region in the vertical direction of each of the left and right side surfaces of the main body portion 113 is exposed to the outside from between the upper portion 161 and the lower portion 163. Hereinafter, these areas will be referred to as exposed areas 117. The exposed region 117 extends in the front-rear direction from the front end to the rear end of the main body portion 113.

The barrel cover 17 is formed in a cylindrical shape and is a portion of the main body housing 11 that covers the barrel portion 111 . Barrel cover 17 is fixed to the front ends of upper part 161 and lower part 163 with screws. Note that an auxiliary handle 93 can be attached to and detached from the barrel cover 17.

The handle portion 18 as a whole is configured as a C-shaped hollow body when viewed from the side. The handle portion 18 includes a grip portion 181, an upper connecting portion 185, and a lower connecting portion 187. The grip portion 181 is a long cylindrical portion and is arranged to extend in the vertical direction. The upper connecting part 185 and the lower connecting part 187 are connected to the upper end and the lower end of the grip part 181, respectively, and extend forward. The upper connecting portion 185 and the lower connecting portion 187 are fixed to the rear end portions of the upper portion 161 and the lower portion 163 with screws, respectively, and cover the upper rear end portion and the lower rear end portion of the main body housing 11. In the vertical direction, the rear cover 12 fixed to the main body housing 11 via the controller case 13 is arranged between the upper connecting part 185 and the lower connecting part 187.

In this way, the outer housing part 16, the barrel cover 17, and the handle part 18 are integrated to form the movable housing 15.

Furthermore, as shown in FIGS. 4 and 5, an elastic member 8 is disposed between the main body housing 11 and the movable housing 15. More specifically, four elastic members 8 are interposed between the rear wall 114 of the main body housing 11 and the handle portion 18 of the movable housing 15, and the main body housing 11 and the movable housing 15 are separated from each other in the front-rear direction. It is biased in the direction of separation. The main body housing 11 and the movable housing 15 are relatively movable in the front-back direction while being biased forward and backward, respectively.

In this embodiment, two of the four elastic members 8 are arranged above the drive shaft A1, and the remaining two are arranged below the drive shaft A1. Hereinafter, when referring to the elastic members 8 separately, the upper elastic member 8 will also be referred to as the upper elastic member 81 and the lower elastic member 8 will also be referred to as the lower elastic member 83. In this embodiment, all four elastic members 8 are compression coil springs.

The upper elastic member 81 is arranged so as to extend in the front-rear direction, and its front end and rear end are connected to the spring receiving part 811 provided on the rear side of the rear wall 114 and the rear of the upper connecting part 185, respectively. It is supported by a spring receiving portion 813 provided on the front side of the wall 186. Note that the upper elastic member 81 is arranged symmetrically with respect to a virtual plane P (see FIG. 10) that includes the drive shaft A1 and extends in the vertical direction (includes the drive shaft A1 and the rotation axis A2 of the motor 2). ing. The lower elastic member 83 is also arranged to extend in the front-rear direction, and its front end and rear end connect to the spring receiving part 831 provided on the rear side of the rear wall 114 and the upper connecting part 185, respectively. It is supported by a spring receiving portion 833 provided on the front side of the rear wall 186. The lower elastic member 83 is arranged symmetrically with respect to the plane P. Furthermore, the lower elastic members 83 are located directly below the upper elastic members 81, respectively.

Due to such an elastic connection structure, the movable housing 15 is placed in the initial position shown in FIGS. 5 and 6 in an initial state where no force is applied in a direction approaching the main body housing 11. The initial position of the movable housing 15 can be said to be the rearmost position within the movable range with respect to the main housing 11. Although detailed illustrations are omitted, the main body housing 11 and the movable housing 15 are provided with stopper parts that define the initial position of the movable housing 15 (restrict movement backward from the initial position) by coming into contact with each other. It is being When the main body housing 11 and the movable housing 15 are in their initial positions, the rear surface of the rear wall of the rear cover 12 and the rear surfaces of the rear wall 188 of the upper connecting portion 185 and the lower connecting portion 187 are approximately flush with each other. .

On the other hand, when a force is applied in a direction approaching the main body housing 11, the movable housing 15 resists the urging force of the elastic member 8 and moves in a direction approaching the main body housing 11 (that is, forward). Move to. In this embodiment, the movable housing 15 is movable to the position shown in FIG. 7 (hereinafter referred to as the proximity position). The proximate position of the movable housing 15 can be said to be the forwardmost position within the movable range with respect to the main body housing 11. Although detailed illustrations are omitted, the main body housing 11 and the movable housing 15 are provided with stopper portions that come into contact with each other to define the proximal position of the movable housing 15 (restrict movement forward from the proximate position). It is being

Note that sliding guides 118 extending in the front-rear direction are provided at the upper and lower ends of the left and right exposed areas 117 of the main body housing 11, respectively. These sliding guides 118 are configured as protrusions that protrude leftward and rightward from the left and right side surfaces of the main body housing 11, respectively. The lower end of the upper part 161 and the upper end of the lower part 163 of the outer housing part 16 slide along the sliding guides 118 at the upper and lower ends of the exposed area 117, respectively, so that the movable housing 15 It is guided to move in the front-rear direction with respect to the housing 11.

In the present embodiment, the upper elastic member 81 and the lower elastic member 83 are configured to apply a load when the movable housing 15 is placed in close proximity (that is, to bias the main body housing 11 and the movable housing 15 in a direction away from each other). The biasing force (elastic force)) is different. More specifically, the four elastic members 8 employ compression coil springs having the same configuration. In other words, all four elastic members 8 are compression coil springs made of the same material, have the same shape, and have the same spring constant. However, the attachment states of the upper elastic member 81 and the lower elastic member 83 to the main body housing 11 and the movable housing 15 are different.

More specifically, the mounting load (also referred to as initial load) of the upper elastic member 81 is set to be larger than the mounting load of the lower elastic member 83. Note that the attachment load refers to a load that is applied to give a predetermined deflection to the elastic member 8 when the elastic member 8 is attached. In other words, the upper elastic member 81 is attached in a more compressed state than the lower elastic member 83, and as shown in FIG. The distance in the front-rear direction of the receiving part 813) is smaller than the mounting height D2 of the lower elastic member 83 (the distance in the front-rear direction between the spring receiving part 831 and the spring receiving part 833).

Due to such a difference in mounting load, the lower elastic member 83 is more likely to be elastically deformed than the upper elastic member 81 when the movable housing 15 and the main housing 11 move relative to each other. More specifically, when the load applied to the movable housing 15 exceeds the attachment load of the lower elastic member 83, the lower elastic member 83 deforms, but the upper elastic member 81 deforms when the load applied to the movable housing 15 further When the load increases and exceeds the attachment load of the lower elastic member 83, deformation begins. When the movable housing 15 is relatively moved to the close position, the amount of compression of the lower elastic member 83 is smaller than the amount of compression of the upper elastic member 81. The load of 83 is smaller. In this way, in this embodiment, the loads (biasing forces) of the upper elastic member 81 and the lower elastic member 83 can be easily made different by using the same compression coil springs in different attachment states. Note that the action of the elastic member 8 during relative movement of the movable housing 15 will be described in detail later.

The internal structure of the housing 10 will be described below.

First, the internal structure of the main body housing 11 will be explained. As shown in FIG. 3, a motor 2 and a drive mechanism 3 are housed within the main body housing 11. The drive mechanism 3 includes a gear reduction mechanism 31, a motion conversion mechanism 33, and a striking element 35.

The motor 2 is disposed within the rear end of the main body housing 11 (that is, the rear end of the main body 113). In this embodiment, the motor 2 is an AC motor driven by power supplied from an external AC power source via a power cord 191. The motor 2 is arranged so that the rotation axis A2 of the output shaft 25 extends in the vertical direction (that is, perpendicular to the drive axis A1). Further, a part of the motor 2 (specifically, a part of the stator and rotor) is on the drive shaft A1.

The gear reduction mechanism 31 is a reduction mechanism made up of a plurality of gears, and is arranged in the upper end of the main body housing 11 on the front side of the motor 2. The gear reduction mechanism 31 is configured to appropriately reduce the rotation of the output shaft 25 and then transmit the rotation to the motion conversion mechanism 33 .

The motion conversion mechanism 33 is a mechanism configured to convert rotational motion transmitted from the gear reduction mechanism 31 into linear motion, and is disposed in the main body housing 11 on the front side of the motor 2. In this embodiment, the motion conversion mechanism 33 is configured as a crank mechanism and includes a crankshaft 331, an eccentric pin 333, a connecting rod 335, and a piston 337.

The crankshaft 331 is configured to be rotated by the gear reduction mechanism 31 around a rotation axis extending in the vertical direction. Note that the crankshaft 331 is rotatably supported by a bearing held on the upper wall of the main body housing 11 (main body portion 113) above the drive shaft A1. The eccentric pin 333 is arranged at a position eccentric from the rotation axis of the crankshaft 331 and protrudes downward from a crank plate provided at the lower end of the crankshaft 331. A connecting rod 335 connects the eccentric pin 333 and the piston 337. Piston 337 is slidably disposed within cylinder 338. The cylinder 338 extends coaxially with the tool holder 112 from the barrel portion 111 to the front end of the main body portion 113 along the drive shaft A1.

The striking element 35 includes a striker 351 and an impact bolt 353. The striker 351 is a striker for applying striking force to the tip tool 91. The striker 351 is arranged in front of the piston 337 within the cylinder 338 and is slidable along the drive shaft A1. The space between the piston 337 and the striker 351 within the cylinder 338 constitutes an air chamber that functions as an air spring. The impact bolt 353 is an intermediate that transmits the kinetic energy of the striker 351 to the tip tool 91. The impact bolt 353 is arranged in front of the striker 351 and is slidable within the tool holder 112 along the drive shaft A1.

When the piston 337 reciprocates in the front-rear direction as the crankshaft 331 rotates, the pressure in the air chamber fluctuates, and the striker 351 slides in the cylinder 338 in the front-rear direction due to the action of the air spring. More specifically, when the piston 337 is moved forward, the pressure in the air chamber increases. The striker 351 is pushed forward at high speed by the action of the air spring and strikes the impact bolt 353. Impact bolt 353 transmits the kinetic energy of striker 351 to tip tool 91. Thereby, the tip tool 91 is linearly driven along the drive axis A1. On the other hand, when the piston 337 is moved rearward, the pressure in the air chamber decreases and the striker 351 is pulled rearward. The tip tool 91 moves rearward together with the impact bolt 353 by being pressed against the workpiece. In this way, the hammering action is repeated.

Next, the internal structure of the movable housing 15 will be explained. As shown in FIG. 8, in the movable housing 15, a switch 183 is housed in a grip portion 181 of the handle portion 18. The switch 183 is normally maintained in an off state, but is configured to be turned on in response to a pressing operation of the trigger 182.

Further, as described above, the controller case 13 is fixed to the rear wall 114 of the main body housing 11. As shown in FIGS. 4 and 8, a substantially central portion of the controller case 13 in the vertical direction (a first storage space 131 to be described later) is covered by the rear cover 12, while the upper and lower portions of the controller case 13 are covered with handles, respectively. It is covered by an upper connecting part 185 and a lower connecting part 187 of the section 18 .

As shown in FIGS. 8, 9, and 10, in this embodiment, the controller case 13 houses a controller 41, and also includes various electric wires 40 (connected via connectors) connected to the controller 41. (not shown in FIG. 9). More specifically, the controller case 13 is formed by a case body 140 and a cover 145 that covers a part of the case body 140. In this embodiment, the case body 140 and the cover 145 are both made of synthetic resin.

The case body 140 is an elongated rectangular box-like body with an open rear side, and has a generally rectangular front wall (bottom wall) and a peripheral wall that protrudes rearward from the outer edge of the front wall. The case body 140 has two storage spaces divided into upper and lower sections. Hereinafter, the part of the case body 140 that defines the first housing space 131 on the upper side will be referred to as a first housing part 141, and the part that defines the second housing space 132 on the lower side will be referred to as a second housing part 142. In addition, in this embodiment, the first accommodation space 131 and the second accommodation space 132 are partitioned by a partition wall. The cover 145 is arranged to cover almost the entire portion of the opening at the rear end of the case body 140 that corresponds to the second accommodation space 132 . Note that the cover 145 is fixed to the case body 140 with screws.

A controller 41 is arranged in the first accommodation space 131 . The controller 41 is a control device configured to control driving of the motor 2. Although detailed illustration is omitted, the controller 41 includes a circuit board and a control circuit mounted on the circuit board. A plurality of electric wires 40 are connected to the controller 41. The electric wires 40 include, for example, an electric wire 401 that connects the power cord 191 and the controller 41, an electric wire 403 that connects the controller 41 and the motor 2 (brush holder), an electric wire 405 that connects the controller 41 and the switch 183, and the like. Some of these electric wires 40 are arranged in the second accommodation space 132. In this embodiment, some of the electric wires 401 and 403 are arranged in the second accommodation space 132.

In this embodiment, the motor 2 is arranged so that the output shaft 25 is orthogonal to the drive shaft A1. In such an arrangement, a space is likely to be created in a region adjacent to the motor 2 along the direction in which the output shaft 25 extends. Therefore, in this embodiment, by utilizing this space, the elongated controller case 13 is fixed to the rear wall 114 so that its long axis extends parallel to the rotation axis of the output shaft 25 of the motor 2. has been done. Further, this arrangement of the controller case 13 is also rational in accommodating the electric wire 403 that connects the controller 41 and the motor 2. In particular, since the electric wire 403 is connected to the lower end (brush holder) of the motor 2, the second housing space 132 is disposed below the first housing space 131, which facilitates wiring. Note that the electric wire 403 is inserted into the main body housing 11 through openings provided in the front wall (bottom wall) and the rear wall 114 of the case main body 140, respectively.

Further, as shown in FIG. 8, in this embodiment, a cushioning material 130 is arranged between a part of the electric wire 40 arranged in the second accommodation space 132 and the inner surface of the controller case 13. More specifically, the cushioning material 130 is provided between a portion of the electric wire 40 (at least the electric wire 403 connected to the motor 2) and the front wall (bottom wall) of the case body 140, and between a portion of the electric wire 40 (at least the electric wire 403 connected to the motor 2) and the front wall (bottom wall) of the case body 140. It is arranged between the electric wire 403 ) and the inner surface of the cover 145 . As the cushioning material 130, an elastic body such as a synthetic resin sponge or rubber is suitably used. The cushioning material 130 prevents a collision between the inner surface of the controller case 13 and a part of the electric wire 40 arranged in the second housing space 132, and protects the electric wire 40 from vibrations of the main body housing 11 and, by extension, the controller case 13. .

Further, a holder 146 for holding the electric wire 40 (or a connector for the electric wire 40) is provided on the rear surface of the cover 145 (that is, the surface facing the rear wall 188 of the lower connecting portion 187). In this embodiment, the holder 146 is flexible and configured as a pair of protrusions that can hold the electric wire 40 or the connector. In this embodiment, holder 146 holds a connector for electric wire 405. The electric wire 405 passes through the lower connecting part 187 and the inside of the grip part 181 and is connected to the switch 183.

The cover 145 also has a sliding portion 147 that slidably engages with the movable housing 15. More specifically, the sliding portion 147 is a plate-shaped portion extending rearward from the lower end of the cover 145, and slides into a recess 189 provided at the lower end of the lower connecting portion 187 of the handle portion 18. It is arranged so that it can be moved.

A portion of the controller case 13 is configured to hold a cord guard 193 for protecting the power cord 191. In other words, the controller case 13 that houses the controller 41 and part of the electric wire 40 is also used to hold the cord guard 193.

More specifically, a front holding part 143 and a rear holding part 148 are provided at the lower ends of the case body 140 and the cover 145 of the controller case 13, respectively. The front holding part 143 and the rear holding part 148 each have a recess that matches the outer circumference of the cord guard 193. When the cover 145 is fixed to the case body 140, the front holding part 143 and the rear holding part 148 engage with the cord guard 193 from the front and rear sides and hold the cord guard 193. Note that the front holding part 143 and the rear holding part 148 are connected to the lower end of the movable housing 15 (more specifically, the lower rear end of the lower part 163 of the outer housing part 16 and the lower connecting part 187 of the handle part 18 It protrudes downward from an opening formed in the lower front end of the.

Furthermore, as shown in FIGS. 3 and 11, the hammer 101 is provided with a vibration damping mechanism 7 configured to reduce longitudinal vibrations generated in the main body housing 11 due to the above-described hammer operation. There is. The vibration damping mechanism 7 of this embodiment includes a pair of left and right dynamic vibration absorbers 70. Note that the pair of dynamic vibration absorbers 70 have the same configuration and are arranged symmetrically with respect to the plane P. The pair of dynamic vibration reducers 70 are attached to the lower end of the main body housing 11 and extend in the front-rear direction parallel to the drive shaft A1. Dynamic vibration absorber 70 is covered by lower portion 163 of outer housing portion 16 .

In addition, in this embodiment, by employing a pair of left and right dynamic vibration absorbers 70, each dynamic vibration absorber 70 can be made smaller compared to the case where vibrations are effectively absorbed by one dynamic vibration absorber. This allows for a compact overall arrangement. Further, the latter half of the dynamic vibration absorber 70 is disposed on the opposite side of a part of the motion conversion mechanism 33 with the drive shaft A1 in between. More specifically, the crankshaft 331 and the dynamic vibration absorber 70, both of which are heavy objects, are arranged on the upper side and the lower side with the drive shaft A1 in between. This ensures good weight balance in the vertical direction. Furthermore, since there is no particular mechanism that needs to be placed in the space on the opposite side of the crankshaft 331 with respect to the drive shaft A1, this space can be used to realize a rational placement of the vibration damping mechanism 7. I can say that.

As shown in FIG. 12, in this embodiment, each dynamic vibration absorber 70 includes a weight 71, two springs 72 arranged on both sides of the weight 71, and a housing section 73 that houses the weight 71 and the springs 72. It is constituted as a subject.

The weight 71 is formed as a long cylindrical member extending in the front-rear direction, and is slidable in the housing portion 73 in the front-rear direction. More specifically, the weight 71 has a large diameter portion 711 having a uniform diameter and a small diameter portion 713 having a smaller diameter than the large diameter portion 711 and protruding from the front and rear ends of the large diameter portion 711. The two springs 72 are each fitted into the small diameter portion 713, and one end of each spring 72 is in contact with the end of the large diameter portion 711. The other end of each spring 72 is in contact with a spring receiving part provided on the inner surface side of both ends of the housing part 73. In addition, in the following, when the two springs 72 are referred to collectively or when referring to either one without distinction, it is simply referred to as the spring 72, and when referring to the spring 72 arranged on the front side of the weight 71 among the two springs 72, it is referred to as the spring 72. , the front spring 721, and when referring to the spring 72 disposed on the rear side of the weight 71, the spring 72 is referred to as the rear spring 723.

The housing portion 73 is a cylindrical case with both ends closed. In this embodiment, the accommodating portion 73 is configured by combining a plurality of members. The accommodating portion 73 is arranged so that its long axis extends in the front-rear direction, and is attached to the lower end of the main body housing 11. The internal space of the housing portion 73 is divided into a front space 731 formed on the front side of the weight 71 and a rear space 733 formed on the rear side of the weight 71 by the weight 71 (specifically, the large diameter portion 711). It is sectioned.

Note that the dynamic vibration absorber 70 of this embodiment is a dynamic vibration absorber of a type (so-called air vibration type) in which the weight 71 is actively vibrated using pressure fluctuations in the air in the barrel portion 111 and the crank chamber 119. It is configured. The crank chamber 119 is a partitioned space in the main body housing 11 in which a crankshaft 331 (crank plate) and an eccentric pin 333 are arranged (see FIG. 3), and the front side is a partitioned space in which a crankshaft 331 (crank plate) and an eccentric pin 333 are arranged. 337. Although detailed illustration is omitted, the crank chamber 119 is generally kept out of communication with the outside due to the seal structure. The front space 731 of the dynamic vibration reducer 70 communicates with the internal space of the barrel portion 111 that accommodates the cylinder 338 (not shown in FIG. 12) via a passage 741. Further, the rear space 733 communicates with the crank chamber 119 via a passage 743.

When performing a hammer operation, the pressure in the internal space of the barrel portion 111 and the crank chamber 119 fluctuate as the motion conversion mechanism 33 and the striking element 35 (see FIG. 3) are driven, and the pressure fluctuation is approximately 180 degrees. It has a phase difference of That is, when the pressure in the internal space of the barrel portion 111 increases, the pressure in the crank chamber 119 decreases, and when the pressure in the internal space of the barrel portion 111 decreases, the pressure in the crank chamber 119 increases. Therefore, by communicating the front space 731 and the rear space 733 of the dynamic vibration absorber 70 with the internal space of the barrel portion 111 and the crank chamber 119, respectively, the weight of the dynamic vibration absorber 70 is reduced by utilizing these pressure fluctuations. 71 can be actively driven in the opposite direction to the piston 337 and the striking element 35. Thereby, vibrations can be absorbed more effectively. Note that since this air excitation method itself is well known, detailed explanation thereof will be omitted here.

The operation of the hammer 101 will be explained below.

When the motor 2 is driven, the motion conversion mechanism 33 is driven via the gear reduction mechanism 31. As the piston 337 and the striker 351 reciprocate in the front-rear direction, the weight 71 of the dynamic vibration absorber 70 reciprocates in the opposite direction to the piston 337 and the striker 351, thereby reducing the back-and-forth vibration generated in the main body housing 11. reduce Further, as shown in FIGS. 6 and 7, the main body housing 11 and the movable housing 15, which are connected via the elastic member 8, move relative to each other in the front and rear direction between the initial position and the close position, so that the main body housing 11 transmission of vibrations to the movable housing 15 can be suppressed.

In this embodiment, as described above, the pair of dynamic vibration absorbers 70 are attached to the lower end portion of the main body housing 11. Therefore, as shown in FIG. 11, in the initial state (when not driven), the overall center of gravity G of the pair of weights 71 is approximately at the same position as the drive shaft A1 in the left-right direction, but as shown in FIG. In addition, it is shifted from the drive shaft A1 in the vertical direction, and specifically, is located below the drive shaft A1. In other words, the center of gravity G is located approximately directly below the drive shaft A1. In such an arrangement, while the dynamic vibration reducer 70 can satisfactorily reduce vibrations occurring in the main body housing 11 in the longitudinal direction, some vibrations tend to occur in the vertical direction. This vertical vibration is particularly caused by the impact of the impact when the piston 337 and striker 351 move forward and the impact bolt 353 hits the tip tool 91, and the weight 71 of the dynamic vibration absorber 70 moves backward. It is considered easy to accept.

In contrast, in the present embodiment, the mounting load of the lower elastic member 83 closer to the center of gravity G of the weight 71 in the vertical direction is set to be smaller than the mounting load of the upper elastic member 81. As a result, the lower elastic member 83 is more easily elastically deformed than the upper elastic member 81 and can effectively absorb this impact, thereby suppressing vertical vibrations from being transmitted to the movable housing 15. I can do it. In particular, in this embodiment, the lower elastic member 83 is disposed on the same side as the center of gravity G with respect to the drive shaft A1, and the upper elastic member 81 is disposed on the opposite side, so that vibrations in the vertical direction are transmitted to the movable housing 15. It is possible to more effectively suppress the transmission of Moreover, the stability of gripping the gripping portion 181 extending in the vertical direction can be maintained well. In this way, in this embodiment, a rational configuration is realized in which vibration transmission to the movable housing 15 can be suppressed while arranging the vibration damping mechanism 7 at a position shifted from the drive shaft A1.

Further, in this embodiment, a part of the electric wire 40 connected to the controller 41 is inside the second accommodation space 132 provided adjacent to the first accommodation space 131 in which the controller 41 is disposed within the controller case 13. It is located in A portion of the electric wire 40 within the second accommodation space 132 is covered by a cushioning material 130 disposed between the electric wire 40 and the inner surface of the controller case 13. Thereby, even if vibration occurs as the hammer 101 is driven, the influence of the vibration on a portion of the electric wire 40 within the second accommodation space 132 can be reduced, and the electric wire 40 can be protected.

Furthermore, since the second accommodation space 132 is covered not only by the case body 140 but also by the cover 145, movement of the electric wire 40 to the outside of the controller case 13 is prevented. Thereby, the electric wire 40 can be held more stably within the controller case 13. In particular, in this embodiment, even when the movable housing 15 moves forward relative to the main body housing 11, the cover 145 prevents the electric wire 40 from being connected to a portion of the movable housing 15 (specifically, to the lower connecting portion 187). The electric wire 40 can be prevented from coming into contact with the rear wall 188), and the electric wire 40 can be more reliably protected.

Note that, as described above, the sliding guide 118 provided in the exposed region 117 guides the relative movement of the outer housing portion 16 in the front-back direction. In addition, a sliding portion 147 provided on the cover 145 slides within a recess 189 provided at the lower end of the lower connecting portion 187 of the handle portion 18, thereby preventing relative movement of the handle portion 18 in the front-back direction. I can guide you.

The correspondence between each component of this embodiment and each component of the present invention is shown below. However, each component of the embodiment is merely an example, and does not limit each component of the present invention. The electric hammer 101 is an example of a "reciprocating tool." Motor 2 and output shaft 25 are examples of a "motor" and an "output shaft", respectively. The drive mechanism 3 and the piston 337 are examples of a "drive mechanism" and a "reciprocating member", respectively. The drive shaft A1 is an example of a "drive shaft." The damping mechanism 7 and the weight 71 are examples of a "vibration damping mechanism" and a "weight", respectively. The main body housing 11 is an example of a "main body housing". The movable housing 15 and the grip part 181 are examples of a "movable part" and a "grip part", respectively. The lower elastic member 83 and the upper elastic member 81 are examples of a "first elastic member" and a "second elastic member", respectively.

The motion conversion mechanism 33 is an example of a "motion conversion mechanism." The dynamic vibration absorber 70 is an example of a "dynamic vibration absorber." The weight 71, the spring 72, and the accommodating portion 73 are examples of a “weight,” a “spring,” and a “accommodating portion,” respectively. The crank chamber 119 is an example of an "internal space."

Note that the above embodiment is merely an example, and the reciprocating tool according to the present invention is not limited to the configuration of the hammer 101 illustrated. For example, changes exemplified below can be made. Note that any one or more of these modifications may be employed in combination with the hammer 101 shown in the embodiment or the features described in each claim.

In the above embodiment, the hammer 101 is illustrated as the reciprocating tool. However, the reciprocating tool configured to linearly drive the tip tool along with the reciprocating movement of the reciprocating member is not limited to the hammer 101. For example, the reciprocating tool may be a hammer drill that is capable of performing a drilling operation that rotates the tip tool in addition to a hammer operation that linearly drives the tip tool. Note that both the hammer 101 and the hammer drill are examples of impact tools. Further, the reciprocating tool may be a reciprocating cutting tool (for example, a reciprocating saw, a saber saw, a jigsaw) configured to cut a workpiece using a tip tool.

Further, the configuration and arrangement relationship of the motor 2, the drive mechanism 3, the main body housing 11 housing the motor 2 and the drive mechanism 3, and the movable housing 15 having the grip portion 181 may be changed as appropriate depending on the reciprocating tool. Examples of changes that can be adopted for these are listed below.

The motor 2 may be a brushless motor instead of a motor with brushes. Moreover, the motor 2 may be a DC motor. In this case, the main body housing 11 is provided with a battery mounting portion to which a battery (for example, a rechargeable battery; also referred to as a battery pack) can be attached and detached. Further, as the motion conversion mechanism 33 of the drive mechanism 3, a known motion conversion mechanism using a swinging member may be employed instead of the crank mechanism of the above embodiment. Furthermore, the motor 2 does not need to be arranged such that the output shaft 25 is orthogonal to the drive axis A1; for example, the output shaft 25 may be arranged obliquely to the drive axis A1, or may be arranged parallel to the drive axis A1. There may be.

The shapes of main body housing 11 and movable housing 15 may be changed as appropriate. For example, in the above embodiment, the movable housing 15 elastically connected to the main body housing 11 has a structure that partially covers the main body housing 11, but the portion of the main body housing 11 covered by the movable housing 15 and its range are different from those in the embodiment. It is not limited to the examples. The sliding portion for guiding the relative movement of the main body housing 11 and the movable housing 15 in the front-back direction is not limited to the sliding guide 118. For example, the sliding guide 118 may be provided at only one location in the vertical direction. Furthermore, the plurality of sliding parts may be provided at different positions from those exemplified in the above embodiments. Alternatively, the sliding portion may be omitted.

Instead of the movable housing 15, a handle portion may be elastically connected to the main body housing 11, and includes a grip portion that is held by the user and does not substantially cover the main body housing 11. The handle portion may include a pair of grip portions that protrude vertically or horizontally with respect to the main body housing 11 instead of on the drive shaft A1.

Further, in the embodiment described above, the controller case 13 that accommodates the controller 41 and a portion of the electric wire 40 is provided on the rear wall 114 of the main body housing 11. However, the controller case 13 may be omitted. For example, the controller 41 may be provided within the main body housing 11 or within the movable housing 15, and may be connected to various electrical components via electric wires 40.

The configuration, number, arrangement position, etc. of the dynamic vibration absorbers 70 of the vibration damping mechanism 7 may be changed as appropriate.

For example, the dynamic vibration reducer 70 may include a weight and at least one spring. That is, the number of springs may be one, or three or more. Further, at least a portion of the accommodating portion 73 may be formed by a portion of the main body housing 11. In the embodiment described above, the dynamic vibration absorber 70 is configured as an air vibration type dynamic vibration absorber, and the weight 71 is actively vibrated using pressure fluctuations in the barrel portion 111 and the crank chamber 119. However, the dynamic vibration absorber 70 may be a normal dynamic vibration absorber that does not actively vibrate the weight 71. Alternatively, the internal space of the accommodating portion 73 may communicate only with the crank chamber 119, and the weight 71 may be vibrated only by pressure fluctuations in the crank chamber 119. Further, the weight 71 may be mechanically vibrated by some kind of member instead of the air pressure fluctuation. For example, the weight 71 may be mechanically vibrated by a lever connected to the crankshaft 331. The vibration damping mechanism 7 may be a mechanism including at least one counterweight instead of the dynamic vibration absorber 70.

Further, the number of dynamic vibration absorbers 70 may be one, or three or more. For example, one dynamic vibration reducer 70 can be provided at the lower end of the main body housing 11 on the plane P, parallel to the drive axis A1. Further, for example, two dynamic vibration absorbers 70 may be provided on the left side or the right side of the main body housing 11.

The number, arrangement position, type, etc. of the elastic members 8 interposed between the main body housing 11 and the movable housing 15 can also be changed as appropriate.

For example, the elastic members 8 include at least two elastic members 8 that are spaced apart from each other in the axial direction of an axis that is perpendicular to the drive shaft A1 and passes through the drive shaft A1 and the center of gravity of the at least one weight 71. Bye. Then, for one of the two elastic members 8 that is closer to the center of gravity G of at least one weight 71, the load when the movable housing 15 is placed in the close position may be set to be smaller than that of the other elastic member 8. . Therefore, for example, when the center of gravity of the weight 71 is shifted to the left or right with respect to the drive axis A1, the two elastic members 8 are arranged apart from each other in the left-right direction.

Furthermore, in the above embodiment, the movable housing 15 can be arranged in close proximity by changing the mounting state (specifically, the mounting load and mounting height) of the upper elastic member 81 and the lower elastic member 83 having the same configuration. The load at the time of the change is different. Instead of this example, for example, the upper elastic member 81 and the lower elastic member 83 may be elastic members having different spring constants. More specifically, the lower elastic member 83 may be a (softer) elastic member (for example, a compression coil spring) having a smaller spring constant than the upper elastic member 81. In this case, even if the mounting loads of the upper elastic member 81 and the lower elastic member 83 are the same, the load on the lower elastic member 83 is smaller when the movable housing 15 is placed in the close position. In this case as well, similar to the above-described embodiment, it is possible to realize a rational configuration that can effectively suppress vibration transmission to the movable housing 15 while arranging the vibration damping mechanism 7 at a position offset from the drive shaft A1. I can do it.

Further, as the elastic member 8, for example, a spring of a different type than a compression coil spring, rubber, a synthetic resin having elasticity (for example, urethane foam), felt, etc. can be employed.

Furthermore, in view of the spirit of the present invention and the above embodiments, the following aspects are constructed. At least one of the following aspects may be employed in combination with one or more of the above-described embodiments and modifications thereof, and the inventions described in each claim.
[Aspect 1]
The drive mechanism includes a striking element configured to strike the tip tool under the action of an air spring as the reciprocating member moves back and forth.
The hitting element 35 is an example of a "hitting element" in this embodiment.
[Aspect 2]
The motion conversion mechanism includes a crankshaft having an eccentric pin,
A portion of the vibration damping mechanism is disposed on the opposite side of the crankshaft across the drive shaft.
The crankshaft 331 and the eccentric pin 333 are examples of a "crankshaft" and an "eccentric pin" in this embodiment, respectively.
[Aspect 3]
The at least one dynamic vibration reducer includes a weight and at least one spring.
[Aspect 4]
In aspect 3,
The at least one spring includes a pair of springs disposed on both sides of the weight in the first direction.
[Aspect 5]
The output shaft extends in the second direction.
[Aspect 6]
The reciprocating tool further includes a sliding guide that guides relative movement of the movable part in the first direction with respect to the main body housing.
The sliding guide 118 is an example of a "sliding guide" in this aspect.

101: electric hammer (hammer), 10: housing, 11: main body housing, 111: barrel part, 112: tool holder, 113: main body part, 114: rear wall, 117: exposed area, 118: sliding guide, 119: Crank chamber, 12: Rear cover, 13: Controller case, 130: Cushioning material, 131: First housing space, 132: Second housing space, 140: Case body, 141: First housing part, 142: Second housing part, 143: Front holding part, 145: Cover, 146: Holder, 147: Sliding part, 148: Rear holding part, 15: Movable housing, 16: Outer housing part, 161: Upper part, 163: Lower part, 17 : Barrel cover, 18: Handle part, 181: Grip part, 182: Trigger, 183: Switch, 185: Upper connecting part, 186: Rear wall, 187: Lower connecting part, 188: Rear wall, 189: Recess, 191 : Power cord, 193: Cord guard, 2: Motor, 25: Output shaft, Drive mechanism 3, 31: Gear reduction mechanism, 33: Motion conversion mechanism, 331: Crankshaft, 333: Eccentric pin, 335: Connecting rod, 337 : Piston, 338: Cylinder, 35: Impact element, 351: Striker, 353: Impact bolt, 40 (401, 403, 405): Electric wire, 41: Controller, 7: Vibration damping mechanism, 70: Dynamic vibration absorber, 71: Weight, 711: Large diameter part, 713: Small diameter part, 72: Spring, 721: Front spring, 723: Rear spring, 73: Accommodation part, 731: Front space, 733: Rear space, 741: Passage, 743: Passage, 8: Elastic member, 81: Upper elastic member, 811: Spring receiving portion, 813: Spring receiving portion, 83: Lower elastic member, 831: Spring receiving portion, 833: Spring receiving portion, 91: Tip tool, 93 : Auxiliary handle, A1: Drive shaft, A2: Rotation shaft, G: Center of gravity, P: Plane

Claims (10)

A reciprocating tool,
a motor having an output shaft;
The tool includes a reciprocating member configured to reciprocate in a first direction along a drive shaft by the power of the motor, and the tip tool is linearly driven as the reciprocating member reciprocates. a configured drive mechanism;
a main body housing that houses the motor and the drive mechanism;
A movable part including a grip part held by a user and connected to the main body housing via a first elastic member and a second elastic member, the movable part having an initial position and a movable part closer to the main body housing than the initial position. a movable part that is movable relative to the main body housing in the extending direction of the drive shaft between the movable part and the proximal position;
a vibration damping mechanism provided in the main body housing and including at least one weight configured to move in a direction opposite to the reciprocating member as the reciprocating member reciprocates;
The center of gravity of the at least one weight is located at a position shifted from the drive shaft in a second direction perpendicular to the drive shaft,
The first elastic member is located closer to the center of gravity than the second elastic member in the second direction,
The reciprocating tool is characterized in that a load on the first elastic member when the movable part is placed in the proximate position is smaller than a load on the second elastic member. The reciprocating tool according to claim 1,
The reciprocating tool is characterized in that the grip portion extends in the second direction. The reciprocating tool according to claim 1 or 2,
In the second direction, the first elastic member is arranged on the same side as the center of gravity with respect to the drive shaft, and the second elastic member is arranged on the opposite side. . The reciprocating tool according to any one of claims 1 to 3,
A portion of the motor is disposed on the drive shaft,
A reciprocating tool, wherein the rotation axis of the output shaft intersects the drive shaft. The reciprocating tool according to claim 4,
The reciprocating device is characterized in that the gripping portion is disposed on the opposite side of the drive mechanism with respect to the motor in the first direction so that a part of the gripping portion is located on the drive shaft. tool. The reciprocating tool according to any one of claims 1 to 5,
The drive mechanism includes a motion conversion mechanism configured to convert rotational motion of the output shaft into linear motion and cause the reciprocating member to reciprocate,
A reciprocating tool, wherein at least a portion of the vibration damping mechanism is disposed on the opposite side of at least a portion of the motion converting mechanism across the drive shaft in the second direction. The reciprocating tool according to any one of claims 1 to 6,
The reciprocating tool is characterized in that the vibration damping mechanism includes at least one dynamic vibration absorber. The reciprocating tool according to claim 7,
The drive mechanism includes a motion conversion mechanism configured to convert rotational motion of the output shaft into linear motion and cause the reciprocating member to reciprocate,
A reciprocating tool, wherein the weight is vibrated by driving the motion converting mechanism. The reciprocating tool according to claim 7 or 8,
The reciprocating tool is characterized in that the at least one dynamic vibration absorber includes a pair of dynamic vibration absorbers arranged in a third direction orthogonal to the first direction and the second direction. The reciprocating tool according to any one of claims 1 to 9,
The reciprocating tool is characterized in that the first elastic member and the second elastic member are springs having the same configuration, but have different attachment states to the main body housing and the movable part.

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