JP7282608B2 - impact tool - Google Patents

Description

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

2. Description of the Related Art An impact tool is known that performs a machining operation (eg, chiseling operation) on a workpiece by linearly driving a tip tool along a predetermined drive shaft. In such an impact tool, when the tip tool is not pressed against the workpiece and no load is applied (hereinafter referred to as a no-load condition), the motor is driven at a low speed so that the tip tool is pressed against the workpiece. When a load is applied (hereinafter referred to as a load state), the motor may be controlled to drive at a higher speed. For example, Patent Document 1 discloses a hammer drill that determines whether or not a load is applied to an output shaft based on acceleration detected by an acceleration detector provided in a housing, and controls driving of a motor. there is

JP-A-2018-58188

In the case of the hammer drill of Patent Document 1, in which the determination of whether or not there is a load is made based on the acceleration, even if the tip tool is not pressed against the workpiece, if the housing moves for some reason, It may be recognized as a load condition.

An object of the present invention is to provide an impact tool capable of appropriately detecting the load state and controlling the drive of the motor.

According to one aspect of the present invention, an impact tool is provided that includes a motor, a drive mechanism, a body housing, a handle, a battery mounting section, a first detection section, and a control section.

The drive mechanism is configured to be capable of linearly driving the tool bit along the drive shaft by the power of the motor. The drive shaft extends in the front-rear direction of the impact tool. The body housing houses the motor and drive mechanism. The handle has a grip that is gripped by the user. Also, the handle is connected to the body housing via an elastic member and is movable relative to the body housing. The battery mounting portion is configured such that a battery as a power source for the motor can be detachably attached. The first detector is configured to detect the relative position of the handle with respect to the body housing. The controller is configured to control the rotational speed of the motor based on the detection result of the first detector.

In the impact tool of this aspect, the rotational speed of the motor is controlled based on the detection result of the first detector, that is, the relative position of the handle with respect to the body housing. When the tool bit is pressed against the workpiece, the handle elastically connected to the body housing moves forward relative to the body housing. That is, the transition from unloaded to loaded conditions corresponds to relative forward movement of the steering wheel. Therefore, according to this aspect, based on the relative position of the steering wheel detected by the first detection section, it is possible to appropriately detect the transition from the no-load state to the load state and control the rotation speed of the motor.

In this aspect, the first detection section only needs to be able to detect the relative position of the handle with respect to the body housing, and can be arranged at any position on the body housing or the handle. From the viewpoint of accurately detecting the relative movement of the handle with respect to the body housing, it is preferable that the first detection section be arranged adjacent to the elastic member. Any known method can be adopted as the detection method of the first detection unit. For example, either a non-contact method (magnetic field detection method, optical method, etc.) or a contact method can be adopted.

In one aspect of the present invention, the control unit drives the motor at a first rotation speed when the handle is arranged at the first position with respect to the body housing, and the handle relatively moves from the first position to the second position. In this case, the motor may be configured to be driven at the second rotational speed. The second position is a position forward of the first position with respect to the body housing. The second rotational speed is faster than the first rotational speed. According to this aspect, it is possible to prevent the motor from being driven at an unnecessarily high speed when the tip tool is not hitting the workpiece, thereby suppressing vibration of the main body housing. In addition, according to this aspect, it is possible to prevent the motor from being driven at an unnecessary high speed, thereby suppressing consumption of the battery, and improving the runtime, which is important for battery-driven impact tools.

Both the first rotation speed and the second rotation speed may be predetermined rotation speeds. Alternatively, both the first rotation speed and the second rotation speed may be set via the operating member operated by the user, or only one of the rotation speeds may be set via the operating member, and The other rotational speed may be set by the controller accordingly. A value greater than zero is adopted for each of the first rotation speed and the second rotation speed.

In this aspect, when the handle relatively moves from the first position to the second position, the control unit does not necessarily drive the motor at the second rotation speed, which is higher than the first rotation speed. Below, it is also possible for the controller to continue to drive the motor at the first rotational speed after the relative movement of the handle to the second position. As such a condition, for example, the rotation speed set as the second rotation speed via the operation member may be equal to or lower than a predetermined first rotation speed or the first rotation speed set via the operation member. mentioned. In this case, the rotational speed set as the second rotational speed via the operating member may be used as the first rotational speed.

In one aspect of the present invention, the first detector may be arranged on the handle. Since the handle is elastically connected to the body housing, transmission of vibration generated in the body housing is suppressed. The first detector has an electronic component. Therefore, by arranging the first detection section on the handle, the first detection section can be protected from vibration.

In one aspect of the present invention, the controller may immediately increase the rotation speed from the first rotation speed to the second rotation speed when the handle relatively moves from the first position to the second position. According to this aspect, since the impact speed of the tip tool on the workpiece immediately increases in accordance with the transition to the load state, it is possible to improve the working efficiency.

In one aspect of the present invention, the controller may gradually increase the rotation speed from the first rotation speed to the second rotation speed when the handle relatively moves from the first position to the second position. According to this aspect, the impact speed of the tip tool on the workpiece gradually increases in accordance with the transition to the load state, so that it is possible to provide the user with a good operational feeling.

In one aspect of the invention, the first rotation speed may be half or less than the second rotation speed. According to this aspect, the consumption of the battery in the no-load state can be suppressed more effectively.

In one aspect of the present invention, when the handle relatively moves from the second position toward the first position, the control unit reduces the rotation speed of the motor from the second rotation speed after a predetermined time has passed since the handle leaves the second position. It may be lowered to the first rotational speed. Note that the predetermined time may be zero or may be longer than zero. For example, the predetermined time may be set in advance at the time of shipment from the factory and stored in a storage device, or may be set by the user via an operation member. If the predetermined time is zero, the controller will immediately decrease the rotation speed of the motor from the second rotation speed to the first rotation speed when the handle is relatively moved from the second position to the first position. In this case, it is possible to realize control with excellent responsiveness to the user releasing the pressing of the tip tool against the workpiece. On the other hand, if the handle is elastically connected to the main body housing, vibration of the main body housing may cause relative movement of the handle, temporarily moving the handle from the second position toward the first position. Therefore, when the predetermined time is longer than zero, the relative movement of the handle due to the cancellation of the pressing of the tip tool against the workpiece is appropriately determined instead of such vibration, and the rotation speed of the motor is decreased. can be done.

In one aspect of the present invention, the drive mechanism may be further configured to rotate the tool bit around the drive shaft by the power of the motor. In this case, the impact tool may further include a second detector capable of detecting the state of motion of the body housing around the drive shaft. The second detector may be provided on the handle. When the tool bit is rotationally driven, the body housing may rotate excessively around the drive shaft for reasons such as the tool bit being buried in the workpiece. The second detection section can be used to detect such a so-called swinging state. The second detector has an electronic component. Therefore, by arranging the second detection section on the handle in which vibration is reduced compared to the main body housing, the second detection section can be protected from vibration. Note that the second detection section may detect the state of motion of the main body housing around the drive shaft, and an acceleration sensor, for example, can be preferably used as the second detection section.

In one aspect of the invention, the drive mechanism may further comprise a dry strike prevention mechanism configured to prevent a dry strike action. In this case, the handle is configured to be placed at the second position at the same time as or after the function of preventing blank striking is released in response to the pushing of the tip tool into the body housing. good too. It should be noted that the prevention of blank striking operation referred to here means preventing the operation of linearly driving the tip tool in an unloaded state, for example, by inhibiting the operation of a part of the drive mechanism. can be realized. Any known configuration can be adopted as the idle-strike prevention mechanism. According to this aspect, when the rotation speed of the motor is increased to the second rotation speed, the operation of linearly driving the tip tool can be started immediately, and good work efficiency can be ensured. Note that the timing control according to this aspect can typically be realized by appropriately setting the specifications (for example, spring constant) of the elastic member.

In one aspect of the present invention, the impact tool may further include a third detector capable of detecting a load on the tip tool. The control section may be configured to control the rotational speed of the motor based on the detection results of the first detection section and the third detection section. More specifically, the controller is configured to drive the motor at the first rotational speed when the handle is positioned at the first position with respect to the body housing and the load on the tool bit does not exceed the threshold value. may have been Further, the control unit operates the motor when the handle relatively moves from the first position to a second position forward of the first position with respect to the body housing, or when the load on the tip tool exceeds a threshold value. , may be configured to drive at a second rotational speed higher than the first rotational speed.

According to this aspect, it is possible to prevent the motor from being driven at an unnecessarily high speed when the tip tool is not hitting the workpiece, thereby suppressing vibration of the main body housing. In addition, according to this aspect, it is possible to prevent the motor from being driven at an unnecessary high speed, thereby suppressing consumption of the battery, and improving the runtime, which is important for battery-driven impact tools. In addition to the relative position of the handle, by using the load separately detected by the third detection unit, it is possible to more reliably detect the transition from the no-load state to the loaded state even in different working conditions. .

Also in this aspect, both the first rotation speed and the second rotation speed may be predetermined rotation speeds. Alternatively, both the first rotation speed and the second rotation speed may be set via the operating member operated by the user, or only one of the rotation speeds may be set via the operating member, and The other rotational speed may be set by the controller accordingly. A value greater than zero is adopted for each of the first rotation speed and the second rotation speed. Further, when the handle relatively moves from the first position to the second position, it is not necessary for the control unit to always drive the motor at the second rotation speed, which is higher than the first rotation speed. It is also permissible for the part to continue to drive the motor at the first rotational speed after the handle has been relatively moved to the second position.

In one aspect of the present invention, the third detector may be configured to detect the drive current of the motor as the load on the tip tool. It is known that the drive current of the motor increases as the load on the tip tool increases. According to this aspect, with a simple configuration, it is possible to detect and use information different in type from the relative position of the handle as the load on the tip tool.

In one aspect of the invention, the motor may be drivable at a higher speed than the second rotational speed. The controller may be configured to drive the motor at the maximum rotational speed when the handle relatively moves from the first position to the second position and the load exceeds the threshold. According to this aspect, when it is more certain from the detection result of the first detection unit and the detection result of the third detection unit that it is in a loaded state, the maximum work efficiency can be exhibited.

In one aspect of the present invention, the impact tool may further include a battery attached to the battery attachment portion.

It is a right side view of a hammer drill. It is a sectional view of a hammer drill. FIG. 4 is a right side view of the handle with the battery attached; FIG. 4 is a cross-sectional view of the handle with a battery attached; FIG. 5 is a cross-sectional view taken along line VV of FIG. 4; 3 is a cross-sectional view taken along line VI-VI of FIG. 2; FIG. FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 6 showing the hammer drill when the handle is in the rearmost position; FIG. 8 is a cross-sectional view corresponding to FIG. 7 showing the hammer drill when the handle is in the forwardmost position; FIG. 3 is a cross-sectional view taken along line IX-IX of FIG. 2; It is a block diagram showing an electrical configuration of a hammer drill.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, a hammer drill 1 will be exemplified as an example of a work tool configured to perform machining work by driving the tip tool 91 . The hammer drill 1 performs linear reciprocating motion of the tip tool 91 attached to the tool holder 39 along a predetermined drive axis A1 (hereinafter referred to as hammer motion), and rotation of the tip tool 91 around the drive axis A1. It is configured to be able to perform an operation (hereinafter referred to as drill operation).

First, a schematic configuration of the hammer drill 1 will be described. As shown in FIGS. 1 and 2, the shell of the hammer drill 1 is mainly formed by a body housing 10 and a handle 15. As shown in FIGS.

The body housing 10 mainly includes two parts, a driving mechanism accommodating portion 11 that accommodates the driving mechanism 3, and a motor accommodating portion 12 that accommodates the motor 2, and is generally L-shaped when viewed from the side. there is

The drive mechanism housing portion 11 is formed as an elongated box-shaped body and extends along the drive shaft A1. A tool holder 39 to which the tip tool 91 can be attached and detached is arranged in one end portion of the drive mechanism accommodating portion 11 in the drive axis A1 direction. The tool holder 39 is supported by the drive mechanism accommodating portion 11 so as to be rotatable around the drive shaft A1. Further, the tool holder 39 is configured to hold the tip tool 91 so as to be non-rotatable and linearly movable in the drive axis A1 direction. One end portion of the drive mechanism accommodation portion 11 in which the tool holder 39 is accommodated is formed in a generally cylindrical shape. An auxiliary handle 95 can be detachably attached to the outer circumference of this cylindrical portion.

The motor accommodating portion 12 is connected and fixed to the driving mechanism accommodating portion 11 at the other end of the driving mechanism accommodating portion 11 in the direction of the driving axis A1 so as not to move relative to the driving mechanism accommodating portion 11. It protrudes away from A1. The motor 2 is arranged in the motor housing portion 12 so that the rotation axis of the motor shaft 25 extends in a direction intersecting the drive axis A1 (more specifically, in a direction oblique to the drive axis A1).

In the following description, for the sake of convenience, the direction in which the drive shaft A1 extends is defined as the front-rear direction of the hammer drill 1, and the one end side where the tool holder 39 is provided is the front side of the hammer drill 1 (also referred to as the tip region side). The opposite side is defined as the rear side. Further, the vertical direction of the hammer drill 1 is defined as the direction perpendicular to the drive shaft A1 and corresponding to the extending direction of the rotating shaft of the motor shaft 25, and the motor accommodating portion 12 protrudes from the driving mechanism accommodating portion 11. The direction is defined as downward, and the opposite direction is defined as upward. Further, a direction orthogonal to the front-rear direction and the up-down direction is defined as the left-right direction.

The handle 15 is generally formed in a substantially C-shape when viewed from the side, and both ends thereof are connected to the body housing 10 . The handle 15 has a grip portion 16 that is gripped by the user. The grip portion 16 is spaced apart at the rear of the body housing 10 and extends generally vertically so as to intersect the drive shaft A1. A trigger 161 that can be pressed (pulled) by the user is provided at the front portion of the upper end of the grip portion 16 . A battery mounting portion 171 to which a rechargeable battery (battery pack) 93 as a power source for the motor 2 and the like can be attached and detached is provided on the lower side of the grip portion 16 . In the hammer drill 1, when the trigger 161 is pulled, the motor 2 is driven to perform hammering and drilling operations.

A detailed configuration of the hammer drill 1 will be described below.

First, the internal structure of the body housing 10 (the drive mechanism accommodating portion 11 and the motor accommodating portion 12) will be described.

As shown in FIG. 2, the drive mechanism accommodating portion 11 is a portion of the body housing 10 that extends in the front-rear direction along the drive shaft A1, as described above. The drive mechanism housing portion 11 houses the drive mechanism 3 configured to drive the tip tool 91 by the power of the motor 2 . In this embodiment, the drive mechanism 3 includes a motion conversion mechanism 30 , a striking element 36 and a rotation transmission mechanism 37 . The motion conversion mechanism 30 and the striking element 36 are mechanisms configured to perform a hammering action that linearly drives the tip tool 91 along the drive axis A1. The rotation transmission mechanism 37 is a mechanism configured to perform a drilling operation to rotationally drive the tip tool 91 around the drive axis A1. Since the configurations of the motion conversion mechanism 30, the striking element 36, and the rotation transmission mechanism 37 are well known, they will be briefly described below.

The motion conversion mechanism 30 is configured to convert the rotary motion of the motor 2 into linear motion and transmit it to the striking element 36 . In this embodiment, a motion converting mechanism 30 using a swinging member 33 is employed. The motion conversion mechanism 30 includes an intermediate shaft 31 , a rotating body 32 , a swinging member 33 and a piston cylinder 35 . The intermediate shaft 31 extends parallel to the drive shaft A1 (in the front-rear direction) below the drive shaft A1. The rotating body 32 is attached to the outer peripheral portion of the intermediate shaft 31 . The swinging member 33 is attached to the outer peripheral portion of the rotating body 32 and swings in the front-rear direction as the rotating body 32 rotates. The piston cylinder 35 is formed in a cylindrical shape with a bottom, and is supported in a cylindrical sleeve 34 so as to be movable in the front-rear direction. The piston cylinder 35 is reciprocated in the front-rear direction as the swing member 33 swings. The sleeve 34 is coaxially connected to and integrated with the rear side of the tool holder 39 . The integrated tool holder 39 and sleeve 34 are rotatably supported around the drive axis A1.

The striking element 36 is configured to linearly drive the tip tool 91 along the drive axis A1 by striking the tip tool 91 by linearly operating. In this embodiment, the striking element 36 includes a striker 361 as a striker and an impact bolt 363 as a meson. The striker 361 is arranged in the piston cylinder 35 so as to be slidable in the direction of the drive shaft A1. A space inside the piston cylinder 35 behind the striker 361 is defined as an air chamber that functions as an air spring. The impact bolt 363 is arranged in the tool holder 39 so as to be slidable in the direction of the drive axis A1.

When the motor 2 is driven and the piston cylinder 35 is moved forward, the air in the air chamber is compressed to increase the internal pressure. Therefore, the striker 361 is pushed forward at high speed, collides with the impact bolt 363 , and transmits kinetic energy to the tip tool 91 . As a result, the tip tool 91 is linearly driven along the drive axis A1 and strikes the workpiece. On the other hand, when the piston cylinder 35 is moved rearward, the air in the air chamber expands to reduce the internal pressure and the striker 361 is pulled rearward. The tip tool 91 moves backward by being pressed against the workpiece. The motion conversion mechanism 30 and the striking element 36 perform hammering action by repeating such actions.

In addition, in this embodiment, a blank striking prevention mechanism 38 configured to prevent a blank striking operation is arranged in the tool holder 39 . Here, the prevention of blank striking operation means that the tip tool 91 is not attached to the tool holder 39 or the tip tool 91 is not pressed against the workpiece, that is, the state in which no load is applied (hereinafter referred to as , no-load condition) to prevent the striker 361 from reciprocating.

The blank-strike prevention mechanism 38 of this embodiment includes a holding member 381 and an O-ring 383 . The holding member 381 is an elastic member arranged around the striker 361 . An O-ring 383 is positioned within the rear end of the retaining member 381 . Although detailed illustration is omitted, when the tip tool 91 is pressed against the workpiece and a load is applied (hereinafter referred to as a loaded state), the rear end of the impact bolt 363 pushed to the rear end position is , is located within the O-ring 383 . When the drive of the motor 2 is continued even in the no-load state, as shown in FIG. It is held in the forwardmost position. As a result, blank firing operation is prevented. The gripping of the striker 361 by the O-ring 383 (that is, the function of preventing blank strike operation) is released when the impact bolt 363 is pushed to the rear end position as the tip tool 91 is pushed into the body housing 10 .

The rotation transmission mechanism 37 is configured to transmit rotational motion of the motor shaft 25 to the tool holder 39 . In this embodiment, the rotation transmission mechanism 37 is configured as a gear reduction mechanism including a plurality of gears, and the rotation of the motor 2 is appropriately reduced and then transmitted to the tool holder 39 .

The hammer drill 1 of this embodiment can be operated in one of three operation modes of a hammer drill mode, a hammer mode, and a drill mode by operating a mode switching dial (not shown) provided on the left side of the drive mechanism housing portion 11. configured to be selectable. The hammer drill mode is an operation mode in which hammer operation and drill operation are performed by driving the motion conversion mechanism 30 and the rotation transmission mechanism 37 . The hammer mode is an operation mode in which power transmission in the rotation transmission mechanism 37 is cut off and only the motion conversion mechanism 30 is driven so that only a hammer operation is performed. The drill mode is an operation mode in which power transmission in the motion conversion mechanism 30 is cut off and only the rotation transmission mechanism 37 is driven so that only a drill operation is performed. Inside the main body housing 10 (more specifically, inside the drive mechanism accommodating portion 11), a mode switching dial is connected, and the motion conversion mechanism 30 and the rotation transmission mechanism 37 are connected to the transmission state according to the operation mode selected by the mode switching dial. and a cutoff state are provided. Since the configuration of such a mode switching mechanism is well known, detailed description and illustration thereof will be omitted here.

As shown in FIG. 2, the motor accommodating portion 12 is a portion of the main body housing 10 that connects to the rear end portion of the drive mechanism accommodating portion 11 and extends downward. The motor 2 is housed in the upper portion of the motor housing portion 12 . In this embodiment, a DC brushless motor is adopted as the motor 2 because it is small and has a high output.

The motor 2 includes a motor body 20 including a stator 21 and a rotor 23 and a motor shaft 25 extending from the rotor 23 and rotating integrally with the rotor 23 . The rotating shaft of the motor shaft 25 extends obliquely downward and forward with respect to the drive shaft A1. An upper end portion of the motor shaft 25 protrudes into the drive mechanism accommodating portion 11, and a small bevel gear 26 is formed in this portion. The small bevel gear 26 meshes with a large bevel gear 311 fixed to the rear end of the intermediate shaft 31 .

A portion of the handle 15 (specifically, the lower connecting portion 18) is arranged in the rear portion of the lower portion of the motor housing portion 12 (that is, the area below the motor 2).

Next, the detailed configuration and internal structure of the handle 15 will be described.

As shown in FIGS. 3 and 4 , handle 15 includes grip portion 16 , controller housing portion 17 , lower connecting portion 18 and upper connecting portion 19 . In the present embodiment, the handle 15 is constructed by connecting left and right halves to each other with screws at a plurality of locations in a state in which internal parts, which will be described later, are assembled.

As described above, the grip portion 16 is arranged to extend in the vertical direction, and the trigger 161 is provided at the front portion of the upper end portion. Note that the trigger 161 is positioned on the drive shaft A1 (see FIG. 2). The grip portion 16 is formed in an elongated cylindrical shape, and the switch 163 is accommodated therein. The switch 163 is normally kept off, and is turned on when the trigger 161 is pulled. The switch 163 is connected to a controller 41 to be described later by wiring (not shown), and outputs a signal indicating an ON state or an OFF state to the controller 41 .

The controller housing portion 17 is connected to the lower side of the lower end portion of the grip portion 16 . The controller housing portion 17 is formed in a rectangular box shape and extends forward from the grip portion 16 . A controller 41 and a speed change dial unit 43 are housed in the controller housing portion 17 .

Although detailed illustration is omitted, the controller 41 includes a control circuit, a three-phase inverter, and a board on which these are mounted. The control circuit is composed of a microcomputer including a CPU, ROM, RAM, timer and the like. The three-phase inverter includes a three-phase bridge circuit using six semiconductor switching elements. By switching each switching element of the three-phase bridge circuit according to the duty ratio indicated by the control signal output from the control circuit, the motor 2 to drive. Although the details will be described later, in this embodiment, the controller 41 controls the driving of the motor 2 based on the on/off state of the switch 163 and the detection results of various sensors and the like, which will be described later.

The variable speed dial unit 43 is a device for accepting the setting of the rotational speed of the motor 2 according to the external operation by the user. Although not shown in detail, the variable speed dial unit 43 includes a dial as an operation member that can be rotated by the user from outside the controller housing 17, and a variable resistance that outputs a resistance value according to the rotation position of the dial. It includes a resistor and a circuit board on which the variable resistor is mounted. The variable speed dial unit 43 is connected to the controller 41 by wiring (not shown), and outputs to the controller 41 a signal indicating a resistance value (that is, a set rotational speed) corresponding to the rotational operation of the dial. Although the details will be described later, in this embodiment, the rotational speed set by the speed change dial unit 43 is used as the rotational speed of the motor 2 under load.

A lower end portion (below the controller 41) of the controller accommodating portion 17 is configured as a battery mounting portion 171 to which the battery 93 can be attached and detached. In this embodiment, the battery mounting portion 171 is configured so that the battery 93 is mounted from the rear side toward the front, and as shown in FIG. 172. The pair of guide rails 172 protrude inward from the lower ends of the left and right side walls of the controller accommodating portion 17 and extend in the front-rear direction. On the other hand, guide grooves 932 extending in the longitudinal direction of the battery 93 are provided on a pair of side surfaces of the substantially rectangular parallelepiped battery 93 . The battery 93 is mounted by being slid forward from the rear side to the battery mounting portion 171 while the guide rail 172 is engaged with the guide groove 932 .

Further, as shown in FIG. 4, a hook 933 is provided on the upper portion of the battery 93 so as to protrude from the upper surface when normally biased upward, and retract below the upper surface in response to pressure. A concave portion 173 that is recessed upward is provided on the lower surface of the battery mounting portion 171 . The hook 933 is retracted downward while the battery 93 is slid, and is urged upward to engage with the recess 173 when it reaches a position facing the recess 173 . In this manner, the battery 93 is held by the guide rails 172 in the vertical direction while being positioned in the front-rear direction by the engagement of the hooks 933 and the recesses 173 . Although detailed illustration is omitted, when the battery 93 is attached to the battery attachment portion 171, the terminals of the battery 93 and the battery attachment portion 171 are electrically connected.

In addition to the battery 93, there are a plurality of types of batteries that can be attached to and detached from the battery mounting portion 171, with different capacities and sizes. In FIG. 1 , the battery 930 having the maximum size among the batteries that can be attached to and detached from the battery mounting portion 171 is indicated by a dashed line. The body housing 10 is configured such that when the battery 930 is mounted in the battery mounting portion 171, the bottom surface of the battery 930 and the bottom surface of the body housing 10 (motor housing portion 12) are flush with each other.

As shown in FIGS. 3 and 4, the lower connecting portion 18 is a portion of the handle 15 that connects to the front end portion of the controller housing portion 17 and extends generally downward. The upper connecting portion 19 is a portion of the handle 15 that connects to the upper end portion of the grip portion 16 and extends forward. In this embodiment, the handle 15 is connected to the body housing 10 via the lower connecting portion 18 and the upper connecting portion 19 so as to be relatively movable. Details of the connecting structure between the lower connecting portion 18 and the upper connecting portion 19 and the main body housing 10 will be described below.

As shown in FIGS. 2 and 6, the lower connecting portion 18 is arranged so as to protrude into the lower rear end portion of the motor accommodating portion 12 and the lower rear end portion of the main body housing 10 (specifically, the motor accommodating portion). 12), it is connected so as to be relatively rotatable about a rotation axis A2 extending in the left-right direction. Although the motor 2 is arranged in the upper portion of the motor accommodating portion 12 as described above, there is an empty area below the motor 2 . Therefore, in this embodiment, the lower connecting portion 18 is arranged using this empty area, and the handle 15 and the motor accommodating portion 12 are connected.

In the present embodiment, the rotation axis A2 is set below the battery mounting portion 171 (more specifically, the guide rail 172 (see FIG. 5)) in the lower connecting portion 18 . Further, as shown in FIG. 4 , the rotation axis A<b>2 is set below the center of gravity G of the handle 15 with the battery 93 attached to the battery attachment portion 171 . Note that the center of gravity G of the handle 15 with the battery 93 attached is generally at the same position as the guide rail 172 in the vertical direction. As described above, the hammer drill 1 can be equipped with a battery larger than the battery 93 . The center of gravity of the handle 15 with a larger battery attached is slightly lower than the center of gravity G, but the pivot axis A2 is at the center of gravity of the handle 15 with the maximum size battery 930 shown in FIG. (not shown). When the battery 93 or a battery of another size is attached to the battery attachment portion 171 , the rotation axis A<b>2 is arranged on the front side of the battery 93 . Further, the rotation axis A2 is set below and behind the motor main body 20 . Further, the rotation axis A2 is set directly below the upper connecting portion 19 (more specifically, the central portion of a long hole 193, which will be described later).

As shown in FIG. 6, the lower connecting portion 18 is provided with a shaft portion 181 extending in the left-right direction between the left and right side wall portions with the rotation axis A2 as the central axis. The left and right halves constituting the handle 15 are each provided with two protrusions extending rightward and leftward along the rotation axis A2. A shaft portion 181 is formed by connecting these projecting portions with screws. Recesses 183 are provided at positions corresponding to both ends of the shaft portion 181 on the outer surface side of the left and right side walls of the lower connecting portion 18 . The recess 183 is configured as a recess having a circular cross section centered on the rotation axis A2. An annular elastic member 185 is fitted in the recess 183 .

On the other hand, projecting portions 121 projecting rightward and leftward are provided on the inner surface sides of the left and right side walls of the motor accommodating portion 12 . The protruding portion 121 is formed in a substantially cylindrical shape, and is arranged so that the respective axes are positioned on a straight line extending in the left-right direction. By fitting the tip end portions of these projecting portions 121 into the elastic member 185 in the concave portion 183, the lower connecting portion 18 and the lower rear end portion of the motor housing portion 12 are connected via the elastic member 185. there is Due to such uneven engagement via the elastic member 185, the lower connecting portion 18 is connected to the motor accommodating portion 12 so as to be relatively rotatable about the rotating shaft A2. In addition, the lower connecting portion 18 can be moved relative to the motor housing portion 12 in all directions of front and back, left and right, and up and down by means of the elastic member 185 .

As shown in FIG. 2, the upper connecting portion 19 is arranged so as to protrude into the rear end portion of the drive mechanism accommodating portion 11, and is connected to the upper rear end portion (more specifically, the upper rear end portion) of the main body housing 10 via an elastic member 191. It is connected so as to be able to move relative to the drive mechanism housing portion 11). In this embodiment, a compression coil spring is employed as the elastic member 191 . A rear end portion of the elastic member 191 is fitted into a spring receiving portion 190 (see FIG. 4) provided at the front end portion of the upper connecting portion 19 . The front end of the elastic member 191 is in contact with the rear surface of the support wall 111 arranged inside the rear end portion of the drive mechanism accommodating portion 11 . In other words, the elastic member 191 is arranged so that the direction in which its elastic force acts generally coincides with the front-rear direction, which is the predominant vibration direction during hammering.

Further, as shown in FIG. 4 , the upper connecting portion 19 has an elongated hole 193 formed on the rear side of the spring receiving portion 190 . The elongated hole 193 is a through hole penetrating the upper connecting portion 19 in the left-right direction, and is longer in the front-rear direction than in the up-down direction. On the other hand, as shown in FIGS. 2 and 7, a stopper portion 113 is provided inside the driving mechanism accommodating portion 11 . The stopper portion 113 is a columnar portion extending in the left-right direction between the left and right side wall portions of the drive mechanism accommodating portion 11 and is inserted through the elongated hole 193 .

In an unloaded state, the upper connecting portion 19 is biased in the front-rear direction away from the main body housing 10 (that is, rearward) by the elastic member 191, and the stopper portion 113 contacts the front end of the elongated hole 193 so that the upper connecting portion 19 is connected to the upper side. It is held at a position that restricts the rearward movement of the portion 19 . The relative position of the upper connecting portion 19 (handle 15) with respect to the body housing 10 at this time is referred to as the rearmost position. On the other hand, when the handle 15 is relatively rotated forward about the rotation axis A2, the stopper portion 113 of the main body housing 10 moves relatively rearward in the elongated hole 193 of the upper connecting portion 19, and the elongated hole 193 is closed. , the long hole 193 can be moved relative to the stopper portion 113 in the longitudinal direction and the vertical direction. The upper connecting portion 19 resists the biasing force of the elastic member 191, and as shown in FIG. Relative movement can be forward to a position. The relative position of the upper connecting portion 19 (handle 15) with respect to the body housing 10 at this time is called the forwardmost position.

Details of the internal structures of the lower connecting portion 18 and the upper connecting portion 19 will be described below.

As shown in FIG. 4 , the lower connecting portion 18 accommodates the acceleration sensor unit 47 and is provided with an adapter mounting portion 490 to which the wireless adapter 49 can be attached and detached. The acceleration sensor unit 47 is arranged at the front side of the shaft portion 181 and at the lower end of the lower connecting portion 18 , and the adapter mounting portion 490 is arranged at the front side of the acceleration sensor unit 47 and at the front end of the lower connecting portion 18 . placed in the department.

In this embodiment, the acceleration sensor unit 47 includes an acceleration sensor having a known configuration, a microcomputer including CPU, ROM, RAM, etc., and a board on which these are mounted. Although the details will be described later, in this embodiment, the driving of the motor 2 is stopped when excessive rotation of the main body housing 10 around the drive shaft A1 occurs. Therefore, the acceleration sensor detects acceleration as information (physical quantity, index) corresponding to the rotation of the main body housing 10 around the drive axis A1. The microcomputer appropriately processes the acceleration detected by the acceleration sensor and determines whether or not the rotation of the main body housing 10 around the drive axis A1 exceeds a predetermined limit value. A specific signal (error signal) is output to the controller 41 when the rotation of the main body housing 10 around the drive shaft A1 exceeds a predetermined limit value.

The case where the rotation of the main body housing 10 around the drive axis A1 exceeds a predetermined limit value corresponds to a state in which the main body housing 10 has excessively rotated around the drive axis A1. In such a state, typically, the tip tool 91 is buried in the workpiece, and the tool holder 39 falls into a non-rotatable state (also referred to as a locked state or blocking state). This occurs when an excessive reaction torque is acting on the

The acceleration sensor unit 47 may output the signal indicating the detection result of the acceleration sensor as it is to the controller 41 without having a microcomputer, and the controller 41 may make the above determination. The drive control of the motor 2 based on the signal output from the acceleration sensor unit 47 will be detailed later.

As shown in FIG. 9, the adapter mounting portion 490 includes a housing portion 491 for housing the wireless adapter 49, an insertion port 492 for inserting and removing the wireless adapter 49 into and from the housing portion 491, and a connector (not shown). include. The insertion port 492 is an opening formed in the right wall portion of the lower connecting portion 18 . Note that the insertion port 492 is normally closed by a removable dustproof cap 493 . The wireless adapter 49 is inserted to the left of the housing portion 491 through the receptacle 492 . When the wireless adapter 49 is inserted to a predetermined position in the accommodating portion 491, the connector of the adapter mounting portion 490 and the connector of the wireless adapter 49 are electrically connected. In addition, as described above, the lower connecting portion 18 is arranged in the lower rear end portion of the motor accommodating portion 12 . Therefore, as shown in FIGS. 1 and 9, an opening 123 slightly larger than the insertion port 492 is provided in the right wall portion of the motor housing portion 12 at a position facing the housing portion 491 (the insertion port 492). is provided. The user can easily insert the wireless adapter 49 into the housing portion 491 of the lower connecting portion 18 from the outside of the motor housing portion 12 through the opening 123 as necessary.

A wireless adapter 49 detachable from the adapter mounting portion 490 is configured to be capable of wireless communication with an external device. Although detailed illustration is omitted, in this embodiment, the wireless adapter 49 has a well-known configuration including a microcomputer including a CPU, ROM, RAM, etc., an antenna, and a connector. When the wireless adapter 49 is attached to the adapter attachment portion 490, it is electrically connected to the controller 41 via a connector. Then, according to a control signal from the controller 41, a predetermined interlocking signal is wirelessly transmitted to a stationary dust collector separate from the hammer drill 1 using radio waves of a predetermined frequency band.

Since such a system itself is publicly known, the controller 41 causes the wireless adapter 49 to transmit an interlocking signal while the trigger 161 is pulled and the switch 163 is turned on. The controller of the dust collector is configured to drive the motor of the dust collector while receiving the interlocking signal transmitted from the wireless adapter 49 . That is, the user of the hammer drill 1 can operate the dust collector in conjunction with the hammer drill 1 simply by pulling the trigger 161 . Note that the wireless adapter 49 is not limited to transmitting an interlocking signal to the dust collector, and may be configured to perform wireless communication with other external devices (for example, mobile terminals).

As shown in FIGS. 6 and 7 , the upper connecting portion 19 is provided with a position sensor 45 for detecting the relative position of the handle 15 with respect to the main body housing 10 . In this embodiment, a Hall sensor having a Hall element is employed as the position sensor 45 . The position sensor 45 is mounted on the substrate 450 and fixed to the left front end of the upper connecting portion 19 so as to face the left side wall portion of the body housing 10 (driving mechanism accommodating portion 11). More specifically, the position sensor 45 is arranged at substantially the same position as the rear end portion of the elastic member 191 in the front-rear direction. A magnet 46 is fixed to the inner surface of the left side wall of the body housing 10 . The position sensor 45 is electrically connected to the controller 41 via wiring (not shown), and sends a specific signal (ON signal) to the controller 41 when the magnet 46 is placed within a predetermined detection range. configured to output.

In this embodiment, as shown in FIG. 7, when the handle 15 is at the rearmost position (initial position) with respect to the main body housing 10, the magnet 46 is arranged within the detection range of the position sensor 45. 45 outputs an ON signal. When the handle 15 moves forward from the rearmost position with respect to the body housing 10 and reaches a predetermined position, the magnet 46 leaves the detection range of the position sensor 45, and the position sensor 45 stops outputting the ON signal. . This predetermined position (hereinafter referred to as the OFF position) is set slightly behind the forwardmost position shown in FIG. does not output an ON signal. Although the details will be described later, the detection result of the position sensor 45 is used for controlling the rotational speed of the motor 2 by the controller 41 .

As described above, the handle 15 is connected at its lower end to the lower rear end of the main body housing 10 so as to be rotatable about the rotary shaft A2, while its upper end is elastically connected to the upper rear end of the main body housing 10 . They are elastically connected via a member 191 . The position of the rotation axis A2 is set below the battery mounting portion 171 (specifically, the guide rail 172). As a result, it is possible to effectively suppress transmission of vibrations generated in the body housing 10 due to the driving of the motor 2 and the drive mechanism 3 to the handle 15 (especially the grip portion 16).

Specifically, the driving of the drive mechanism 3 causes the body housing 10 to vibrate in the front-rear direction and the vertical direction. On the other hand, while the handle 15 is relatively rotated around the rotation axis A2, the vibration in the front-rear direction can be dealt with, and in particular, the control in the direction of the drive axis A1 (the front-rear direction) caused by the reciprocation of the tip tool 91 can be controlled. Vibration can be absorbed by the elastic member 191 . In addition, in the present embodiment, by arranging the rotating shaft A2 below the battery mounting portion 171, the separation distance between the elastic member 191 and the rotating shaft A2 is ensured as large as possible. As a result, the elastic member 191 can efficiently absorb vibrations at positions where the amplitude is large with respect to the body housing 10 , so that transmission of vibrations to the grip portion 16 can be effectively suppressed.

In particular, in the present embodiment, the rotation axis A2 is set directly below the upper connecting portion 19 (more specifically, approximately directly below the rear end portion of the elastic member 191). That is, the fulcrum of rotation and the elastic connecting portion are set at approximately the same position with respect to the direction of the drive shaft A1. In addition, the elastic member 191 is arranged so as to be able to expand and contract parallel to the drive shaft A1. Therefore, it is possible to efficiently reduce the vibration in the front-rear direction.

Further, the position of the rotation axis A2 is set below the center of gravity G of the handle with the battery 93 attached to the battery attachment portion 171 . In the handle 15 whose upper end is elastically connected to the body housing 10 and whose lower end is rotatably connected to the body housing 10, when the rotation axis A2 is positioned above the center of gravity G, the handle 15 rotates around the rotation axis A2. It becomes difficult to rotate. On the other hand, in this embodiment, by arranging the rotation axis A2 below the center of gravity G, the handle 15 can be easily rotated about the rotation axis A2 relative to the vibration of the main body housing 10, and the handle 15 can be gripped. It enhances the vibration suppression effect on the part.

Furthermore, in this embodiment, the projecting portion 121 of the motor accommodating portion 12 is fitted into the recessed portion 183 of the lower connecting portion 18 via an annular elastic member 185 . Therefore, the ring-shaped elastic member 185 can also suppress the transmission of longitudinal and vertical vibrations generated in the body housing 10 to the handle 15 .

The hammer drill 1 also includes a controller 41 , a variable speed dial unit 43 , a position sensor 45 , an acceleration sensor unit 47 , a wireless adapter 49 and an adapter mounting portion 490 . All of these have electronic components and are desired to be protected from vibration. Therefore, by arranging these on the handle 15, adequate protection from vibration is realized. In addition, in the present embodiment, the lower connecting portion 18 is not only connected to the motor housing portion 12, but also utilizes an empty area existing below the motor 2 in the motor housing portion 12 to connect the acceleration sensor unit 47 and the wireless communication device. It also exhibits the function of arranging the adapter 49 while protecting it from vibration. By arranging the position sensor 45 on the upper connecting portion 19 adjacent to the elastic member 191, an optimum arrangement for detecting relative movement of the handle 15 with respect to the body housing 10 in the longitudinal direction is realized.

Drive control of the motor 2 by the controller 41 will be described below.

In this embodiment, so-called soft no-load control is performed by the controller 41 (more specifically, the CPU of the controller 41). The soft no-load control is a drive control method for the motor 2 in which the motor 2 is driven at a low speed in a no-load state when the switch 163 is in an ON state, and the rotation speed is increased in a load state. It is also called rotation control. Hereinafter, the rotation speed of the motor 2 in the no-load state will be referred to as the first rotation speed, and the rotation speed of the motor 2 in the loaded state will be referred to as the second rotation speed. In the present embodiment, the controller 41 sets the rotation speed set by the speed change dial unit 43 as the second rotation speed, and sets the rotation speed half of the second rotation speed as the first rotation speed. Then, the motor 2 is driven by setting a duty ratio according to the first rotation speed or the second rotation speed and outputting a control signal to the three-phase inverter.

In this embodiment, the detection result of the position sensor 45 is used to distinguish between the no-load state and the load state in soft no-load control. As described above, position sensor 45 detects the relative position of handle 15 with respect to body housing 10 . In the no-load state, the upper connecting portion 19 is arranged at the rearmost position due to the biasing force of the elastic member 191 (see FIGS. 2 and 7), and the position sensor 45 detects the magnet 46 and outputs an ON signal. are doing. The controller 41 determines that the motor 2 is in the no-load state when the output from the position sensor 45 is on, and drives the motor 2 at the first rotation speed when the switch 163 is turned on from the off state. Start. As the motor 2 is driven, the drive mechanism 3 is driven according to the operation mode selected via the mode switching dial (not shown), and at least one of the hammer operation and the drill operation is performed.

When the user presses the tip tool 91 against the workpiece while gripping the grip portion 16, the handle 15 relatively rotates forward about the rotation axis A2, and the upper connecting portion 19 engages the elastic member 191. Move forward from the rearmost position while compressing. When the upper connecting portion 19 reaches the OFF position, the position sensor 45 stops outputting the ON signal. The controller 41 recognizes the change from ON to OFF of the output from the position sensor 45 as the transition from the no-load state to the loaded state. When the controller 41 recognizes the transition to the load state while the motor 2 is being driven at the first rotation speed, the controller 41 increases the rotation speed of the motor 2 to the second rotation speed. At this time, the controller 41 may immediately increase the rotational speed of the motor 2 to the second rotational speed, or may gradually increase it. When the rotational speed is immediately increased, the speed of the reciprocating motion or rotation of the tip tool 91 is immediately increased, thereby improving working efficiency. On the other hand, when the rotation speed is gradually increased, the reciprocating motion or rotation speed of the tip tool 91 is gradually increased, so that the user can be provided with a good operational feeling. When the switch 163 is turned on while the output from the position sensor 45 is off, the controller 41 starts driving the motor 2 at the second rotational speed. Also in this case, the controller 41 may immediately increase the rotation speed of the motor 2 to the second rotation speed, or may increase it gradually.

In the present embodiment, the handle 15 is moved to the OFF position at the same time as or after the blank striking prevention mechanism 38 is released in response to the pushing of the tip tool 91 into the main body housing 10 . configured to be placed. That is, the impact bolt 363 is pushed to the rear end position, and the handle 15 reaches the off position at the same time as or after the striker 361 is separated from the O-ring 383 . For this reason, the specifications (for example, spring constant) of the elastic member 191 are appropriately set. By controlling the timing in this way, it is possible to quickly start the reciprocating motion of the striker 361 when the rotation speed of the motor 2 is increased to the second rotation speed, thereby ensuring good work efficiency.

In addition, the controller 41 recognizes that the output from the position sensor 45 has changed from off to on (that is, the upper connecting portion 19 has moved rearward from the off position toward the rearmost position) while the switch 163 is in the on state. Sometimes a timer monitors the duration of the ON state. Then, the rotation speed of the motor 2 is returned to the first rotation speed only when the ON state continues for a predetermined time (longer than zero in this embodiment). This is to reliably distinguish between a temporary change to the ON state when the body housing 10 is vibrating due to machining work and a change from the loaded state to the unloaded state. Specifically, the upper connecting portion 19 reciprocates in the front-rear direction with respect to the main body housing 10 due to the vibration of the main body housing 10 in the front-rear direction. In this case, the output from the position sensor 45 switches between on and off at short intervals. On the other hand, when the pressing of the tip tool 91 is released and the state shifts to the no-load state, the ON state continues for a predetermined time after the output from the position sensor 45 is switched from OFF to ON. Therefore, in this embodiment, the control as described above is adopted.

Regardless of whether the motor 2 is driven at the first rotational speed or the second rotational speed, when the trigger 161 is released and the switch 163 is turned off, the controller 41 starts the motor. 2 is stopped.

Furthermore, in this embodiment, in addition to the soft no-load control, control based on the detection result of the acceleration sensor unit 47 is also performed. More specifically, the controller 41 recognizes the error signal output from the acceleration sensor unit 47 whether the motor 2 is driven at the first rotation speed or at the second rotation speed. If so, the drive of the motor 2 is stopped. As mentioned above, the error signal is indicative of excessive rotation of the main body housing 10 about the drive axis A1. Therefore, if this excessive rotation is caused by the locked state of the tool holder 39, this is to prevent further rotation. In addition to the error signal, the controller 41 determines whether or not excessive rotation occurs based on other information (for example, the torque acting on the tip tool 91 and the drive current of the motor 2). good too. Moreover, the controller 41 preferably not only stops energizing the motor 2 , but also electrically brakes the motor 2 in order to prevent the motor shaft 25 from continuing to rotate due to the inertia of the rotor 23 .

As described above, according to the drive control of the motor 2 of the present embodiment, transition from the unloaded state to the loaded state can be appropriately detected based on the relative position of the steering wheel 15 detected by the position sensor 45. , the rotational speed of the motor 2 can be increased. As a result, it is possible to prevent the motor 2 from being driven at an unnecessary high speed when the tip tool 91 is not hitting the workpiece, suppress vibration of the body housing 10, and suppress consumption of the battery 93. can. In particular, in the present embodiment, since the first rotational speed under no load is half the second rotational speed under load, the consumption of the battery 93 in the no-load state can be suppressed more effectively. .

By the way, as described above, the forward relative movement of the handle 15 changes from the unloaded state in which the tip tool 91 is not pressed against the workpiece to the loaded state in which the tip tool 91 is pressed against the workpiece. Equivalent to migration. However, depending on the type of machining work, the handle 15 may move forward only slightly when transitioning from the unloaded state to the loaded state. For example, when the angle formed by the tip tool 91 and the workpiece is small, such as when peeling off a covering material (for example, a tile), the tip tool 91 is not strongly pressed backward against the main body housing 10 . Therefore, the amount of relative forward movement of the handle 15 is very small. In such a case, there is a possibility that the transition from the no-load state to the loaded state cannot be determined accurately based only on the detection result of the position sensor 45 . Therefore, the controller 41 controls the rotation speed of the motor 2 (soft no-load control) based on the relative position of the handle 15 with respect to the main body housing 10 and other information (physical quantity, index) corresponding to the load on the tip tool 91. you can go Other information (physical quantity, index) corresponding to the load on the tip tool 91 includes, for example, the current value of the motor 2, the vibration (acceleration) of the body housing 10, and the temperature of the battery 93.

A modification in which the drive current for the motor 2 is employed will be specifically described below.

FIG. 10 shows the electrical configuration of the hammer drill 1 when the driving current of the motor 2 is adopted. As shown in FIG. 10 , the controller 41 is electrically connected to a three-phase inverter 421 , a Hall sensor 423 and a current detection amplifier 425 . Based on the signal indicating the rotor rotation angle input from the Hall sensor 423, the controller 41 controls the energization of the motor 2 through the switching elements of the three-phase inverter 421 as described above, thereby rotating the motor 2. Control speed. The current detection amplifier 425 is configured to detect the drive current of the motor 2 . More specifically, the current detection amplifier 425 is configured to convert the driving current of the motor 2 into a voltage using a shunt resistor, and output the signal amplified by the amplifier to the controller 41 . Also, as described above, the controller 41 is electrically connected to the switch 163 , the speed change dial unit 43 , the position sensor 45 and the acceleration sensor unit 47 .

In this modification, the controller 41 drives the motor 2 at a low speed when both the detection result of the position sensor 45 and the detection result of the current detection amplifier 425 indicate a no-load state, and the detection result of the position sensor 45 and When at least one of the detection results of the current detection amplifier 425 indicates a load state, the motor 2 is driven at a higher speed.

More specifically, when the output from the position sensor 45 is on and the drive current value calculated based on the output signal of the current detection amplifier 425 does not exceed a predetermined threshold, the position sensor 45 detects It can be said that both the result and the detection result of the current detection amplifier 425 indicate the no-load condition. In this case, the controller 41 drives the motor 2 at the first rotational speed, as in the above embodiment. On the other hand, when the output from the position sensor 45 is off, or when the calculated drive current value exceeds the threshold, one of the detection result of the position sensor 45 and the detection result of the current detection amplifier 425 indicates the load state. It can be said that it shows In this case, the controller 41 drives the motor 2 at the second rotational speed, as in the above embodiment. In addition, in this modification, the upper limit of the speed that can be set by the speed change dial unit 43 is set lower than the maximum rotational speed of the motor 2 . Therefore, when the output from the position sensor 45 is off and the calculated drive current value exceeds the threshold (that is, both the detection result of the position sensor 45 and the detection result of the current detection amplifier 425 are load condition), the motor 2 is driven at the maximum rotational speed (that is, at a speed higher than the second rotational speed).

In this way, the hammer drill 1 of this modified example uses a plurality of types of information indicating the load on the tip tool 91, so that it is possible to more reliably detect the transition from the no-load state to the loaded state even in different working states. . Further, by adopting the drive current of the motor 2, it is possible to detect and use information different in type from the relative position of the handle 15 as the load on the tip tool 91 with a simple configuration. Furthermore, when the relative position of the handle 15 and the drive current value of the motor 2 make it more certain that the motor is in a loaded state, the motor 2 is driven at the maximum rotational speed, so that the maximum work efficiency can be exhibited. .

As described above, when the vibration (acceleration) of the body housing 10 is adopted as another information (physical quantity, index) corresponding to the load on the tip tool 91, the controller 41 detects the position sensor 45. Based on the result and the detection result of the acceleration sensor unit 47, similar control may be performed. Further, when the temperature of the battery 93 is adopted as another information (physical quantity, index) corresponding to the load on the tip tool 91, for example, a temperature sensor is provided near the battery 93 mounting portion, and the controller 41 , the same control may be performed based on the detection result of the position sensor 45 and the detection result of the temperature sensor.

The above embodiment is merely an example, and the impact tool according to the present invention is not limited to the configuration of the hammer drill 1 illustrated. For example, the modifications exemplified below can be made. It should be noted that any one of these modifications, or a plurality thereof, may be employed in combination with the hammer drill 1 shown in the embodiment or with the inventions described in each claim.

In the above embodiment, the hammer drill 1 is exemplified as an impact tool configured to linearly drive the tip tool 91, but the present invention is also applicable to other impact tools (eg, electric hammer). . The configuration and arrangement of the motor 2, the drive mechanism 3, the body housing that accommodates the motor 2 and the drive mechanism 3, and the handle 15 having the grip portion 16 can be changed as appropriate according to the impact tool.

For example, the elastic connection structure between the body housing 10 and the handle 15 may be changed as appropriate. For example, each of the upper end and the lower end of the handle 15 may be connected to the body housing 10 via one or more elastic members so as to be relatively movable in the direction of the drive shaft A1 (front-rear direction). Alternatively, only the upper end of the handle 15 may be elastically connected to the body housing 10 in a cantilevered manner. In addition to the compression coil spring, various springs, rubber, and synthetic resin can be used as the elastic member. The position sensor 45 is preferably provided near the elastic member at the upper end or lower end of the handle 15, but may be provided at other positions. Also, the position sensor 45 may be provided on the body housing 10 side.

The battery mounting portion 171 may be provided on the body housing 10 instead of being provided on the handle 15 . Also, a plurality of batteries may be attachable.

The position sensor 45 can be changed to another detection mechanism as long as it can detect the relative position of the handle 15 with respect to the main body housing 10 . For example, a non-contact type (for example, optical) sensor other than the magnetic field detection type may be employed, or a contact type detection mechanism (for example, a mechanical switch) may be employed.

The acceleration sensor unit 47 may be omitted. Also, the arrangement position may be inside the body housing 10 instead of the handle 15 . Note that the acceleration sensor unit 47 is preferably arranged at a position as far away from the drive axis A1 as possible in order to properly detect the state of motion around the drive axis A1.

The contents of the soft no-load control exemplified in the above embodiment may be changed as appropriate. For example, the value of the ratio of the first rotation speed to the second rotation speed may be a value other than one-half. Also, both the first rotation speed and the second rotation speed may be predetermined, or both the first rotation speed and the second rotation speed are set via the speed change dial unit 43 or other operation member. It may be possible.

Further, the controller 41 may use a preset rotation speed (referred to as no-load rotation speed) as the first rotation speed, and may use the rotation speed set by the speed change dial unit 43 as the second rotation speed. When the rotation speed set by the speed change dial unit 43 is equal to or lower than the no-load rotation speed, the controller 41 sets the rotation speed set by the speed change dial unit 43 as the first rotation speed regardless of the relative position of the handle 15. Instead, the drive at the first rotation speed may be continued while the switch 163 is in the ON state. In addition, the controller 41 uses the rotation speed set by the speed change dial unit 43 as the rotation speed corresponding to the maximum pull operation amount of the trigger 161, and changes the rotation speed according to the operation amount (operation ratio) of the trigger 161. may In this case as well, the controller 41 drives the motor 2 at a rotational speed corresponding to the operation amount when the rotation speed corresponding to the operation amount is equal to or lower than the no-load rotation speed when there is no load, and the rotation speed exceeds the no-load rotation speed. If so, the motor 2 should be driven at the no-load rotational speed. In other words, in either case, the controller 41 may control the rotation speed of the motor 2 so as not to exceed the no-load rotation speed when there is no load.

Furthermore, in the above embodiment, when the upper connecting portion 19 moves rearward from the off position toward the rearmost position, the controller 41 reduces the rotational speed of the motor 2 to Return to 1 rotation speed. However, the controller 41 may immediately return the rotation speed of the motor 2 to the first rotation speed when the upper connecting portion 19 moves rearward from the off position toward the rearmost position. That is, the predetermined time may be zero. In this case, it is possible to realize control with excellent responsiveness to the user releasing the pressing of the tip tool against the workpiece. The predetermined time may be set in advance at the time of shipment from the factory and stored in a ROM or other non-volatile memory, or may be set by the user via some operation member.

In the above embodiment, the controller 41 is exemplified by a microcomputer including a CPU. may consist of devices. The impact control processing of the above embodiments and modifications may be distributed by a plurality of control circuits.

Correspondence between each component of the above embodiment and modifications and each component of the present invention is shown below. The hammer drill 1 is an example of the "percussion tool" of the present invention. The motor 2 is an example of the "motor" of the present invention. The drive mechanism 3 is an example of the "drive mechanism" of the present invention. The drive shaft A1 is an example of the "drive shaft" of the present invention. The tip tool 91 is an example of the "tip tool" of the present invention. The body housing 10 is an example of the "body housing" of the present invention. The handle 15, the grip portion 16, and the elastic member 191 are examples of the "handle", the "gripping portion", and the "elastic member" of the present invention, respectively. The battery mounting portion 171 and the battery 93 are examples of the "battery mounting portion" and the "battery" of the present invention, respectively. The position sensor 45 is an example of the "first sensor" of the present invention. The controller (CPU) 41 is an example of the "control section" of the present invention. The rearmost position of the handle 15 is an example of the "first position" of the present invention. The off position of the handle 15 is an example of the "second position" of the present invention. The acceleration sensor unit 47 is an example of the "second sensor" of the present invention. The blank firing prevention mechanism 38 is an example of the "blank firing prevention mechanism" of the present invention. Current detection amplifier 425 is an example of the "third detection section" of the present invention.

Furthermore, in view of the gist of the present invention and the above-described embodiments, the following aspects are constructed. The following aspects can be employed in combination with the hammer drill 1 shown in the embodiment and the above modifications, or the inventions described in each claim.
[Aspect 1]
the upper end of the handle is connected to the rear end of the body housing via an elastic member so as to be relatively movable,
the lower end of the handle is connected to the rear end of the main body housing so as to be relatively rotatable about a rotation axis extending in the left-right direction;
The first detector is arranged at the upper end of the handle.
[Aspect 2]
The first detector is arranged near the elastic member.
[Aspect 3]
The battery mounting portion is provided on the handle.

1: Hammer Drill 10: Body Housing 11: Drive Mechanism Accommodating Part 111: Support Wall 113: Stopper Part 12: Motor Accommodating Part 121: Protruding Part 123: Opening 15: Handle 16: Grip Part 161: Trigger 163: Switch 17: Controller Housing portion 171 : Battery mounting portion 172 : Guide rail 173 : Recess 18 : Lower connection portion 181 : Shaft portion 183 : Recess 185 : Elastic member 19 : Upper connection portion 190 : Spring receiving portion 191 : Elastic member 193 : Long hole 2 : Motor 20: Motor body 21: Stator 23: Rotor 25: Motor shaft 26: Small bevel gear 3: Drive mechanism 30: Motion conversion mechanism 31: Intermediate shaft 311: Large bevel gear 32: Rotating body 33: Swing member 34: Sleeve 35: Piston cylinder 36: Striking element 361: Striker 363: Impact bolt 37: Rotation transmission mechanism 38: Blank striking prevention mechanism 381: Holding member 383: O-ring 39: Tool holder 41: Controller 421: Three-phase inverter 423: Hall sensor 425: Current detection amplifier 43: Speed dial unit 45: Position sensor 450: Substrate 46: Magnet 47: Acceleration sensor unit 49: Wireless adapter 490: Adapter mounting part 491: Housing part 492: Insertion port 493: Cap 91: Tip tool 93: Battery 930: Battery 932: Guide groove 933: Hook 95: Auxiliary handle A1: Drive shaft A2: Rotating shaft G: Center of gravity

Claims (11)

an impact tool,
a motor;
a drive mechanism configured to linearly drive the tip tool along a drive shaft extending in the longitudinal direction of the impact tool by the power of the motor;
a body housing that houses the motor and the drive mechanism;
a handle having a grip portion to be gripped by a user, connected to the body housing via an elastic member, and movable relative to the body housing;
a battery loading unit to which a battery as a power supply for the motor can be attached and detached;
a first detector capable of detecting the relative position of the handle with respect to the body housing;
a control unit configured to control the rotation speed of the motor based on the detection result of the first detection unit ;
The control unit
driving the motor at a first rotational speed when the handle is disposed in a first position relative to the body housing;
When the handle is relatively moved from the first position to a second position forward of the first position with respect to the body housing, the motor is rotated to a second rotation speed higher than the first rotation speed. configured to drive with
When the handle moves relatively from the second position toward the first position, the rotational speed is reduced from the second rotational speed after a predetermined time longer than zero has elapsed after leaving the second position. An impact tool characterized by being lowered to the first rotational speed . The impact tool according to claim 1 ,
The impact tool, wherein the control unit immediately increases the rotation speed from the first rotation speed to the second rotation speed when the handle relatively moves from the first position to the second position. The impact tool according to claim 1 or 2 ,
The control unit gradually increases the rotation speed from the first rotation speed to the second rotation speed when the handle relatively moves from the first position to the second position. . The impact tool according to any one of claims 1 to 3 ,
The impact tool, wherein the first rotational speed is half or less than the second rotational speed. The impact tool according to any one of claims 1 to 4 ,
The drive mechanism further comprises a blank-strike prevention mechanism configured to prevent a blank-strike operation,
The handle is configured to be arranged at the second position at the same time as or after the function of preventing the blank striking operation is released in response to the pushing of the tip tool into the main body housing. A striking tool characterized by: The impact tool according to any one of claims 1 to 5 ,
The impact tool, wherein the first detection section is arranged on the handle. The impact tool according to any one of claims 1 to 6 ,
The drive mechanism is further configured to be capable of rotating the tool bit around the drive shaft by the power of the motor,
further comprising a second detection unit capable of detecting a state of motion of the body housing around the drive shaft;
The impact tool, wherein the second detector is provided on the handle. The impact tool according to claim 1,
further comprising a third detection unit capable of detecting a load on the tip tool;
The control unit is configured to control the rotational speed of the motor based on the detection results of the first detection unit and the third detection unit,
The control unit
driving the motor at the first rotational speed when the handle is positioned at the first position and the load on the tool bit does not exceed a threshold;
When the handle relatively moves from the first position to the second position, or when the load on the tip tool exceeds the threshold value, the motor is driven at the second rotation speed. A striking tool characterized by comprising: An impact tool according to claim 8 ,
The impact tool, wherein the third detection unit is configured to detect a driving current of the motor as the load. The impact tool according to claim 8 or 9 ,
The motor is drivable at a speed higher than the second rotational speed,
The controller is configured to drive the motor at a maximum rotational speed when the handle relatively moves from the first position to the second position and the load exceeds the threshold. A striking tool characterized by: The impact tool according to any one of claims 1 to 10 ,
An impact tool, further comprising a battery attached to the battery attachment portion.

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