JPWO2017002517A1 - Impact tool - Google Patents

Abstract

Provided is an impact tool capable of improving operability and workability. The striking tool includes a motor (31) housed in the housing (14), a rotation transmission mechanism (51) for transmitting the rotational force of the motor (31) to the tip tool, and the striking force of the rotational force of the motor (31). A hammer transmission mechanism (41) that converts the rotation transmission mechanism to the tip tool, and a mode selection dial (61) as a mode selection mechanism that switches the rotation transmission mechanism (51) between a rotation transmission state and a transmission stop state. Yes. When the adjustment mode is selected by the mode selection dial (61), the motor (31) is driven at an adjustment mode rotational speed lower than that in the normal operation mode, and the rotational force of the motor (31) is transmitted to the tip tool. Thereby, the direction of the tip tool can be automatically adjusted by the motor (31).

Description

The present invention relates to an impact tool for applying an impact force to a work object using an electric motor as a drive source.

There are hammers and hammer drills as impact tools using an electric motor as a drive source. A hammer is used when a striking force is transmitted to the tip tool and an impact force is applied to the work object with the tip tool to perform grinding or grooving of concrete or the like. The hammer drill has a hammer mode and a hammer drill mode. The hammer drill mode is used when a drilling operation is performed by rotating a tip tool while applying an impact force to concrete.

Patent Document 1 discloses a hammer drill having a neutral mode in addition to a hammer drill mode, a hammer mode, and a drill mode.

JP 2002-192481 A

When the work object is pulverized by the impact tool, a cutter is used as a tip tool, and when a drilling operation is performed on the work object, a scoop is used as a tip tool. A tip tool such as a cutter or a scoop has a cutting edge extending in a direction orthogonal to a direction in which a striking force is applied to a work target. For this reason, the direction of the cutting direction of the cutting edge of the tip tool, that is, the posture, may be changed in accordance with the work mode. The neutral mode is selected so that the operator can easily adjust the direction of the cutting edge of the tip tool. When the neutral mode is selected, the tip tool is set in the idling state, so that the operator can change the direction of the blade edge manually.

However, in order to change the direction of the blade edge, the operator needs to manually rotate the tip tool. For this reason, the adjustment work of the direction of the cutting edge of the tip tool is troublesome, and the operability and workability of the impact tool cannot be improved.

An object of the present invention is to provide a striking tool capable of easily adjusting the direction of a tip tool and improving operability and workability.

An impact tool according to an embodiment of the present invention includes a motor housed in a housing, a rotation transmission mechanism that transmits the rotational force of the motor to a tip tool, and the rotational force of the motor converted into an impact force. An impact tool comprising: an impact transmission mechanism that transmits to a tip tool; a mode selection mechanism that switches the rotation transmission mechanism between a rotation transmission state and a transmission stop state; and a control unit that controls driving of the motor, The mode selection mechanism includes an adjustment mode that adjusts the direction of the tip tool in the rotation direction, and the control unit adjusts the rotation speed of the motor lower than that in the normal operation mode when the adjustment mode is selected. Drive at rotational speed.

When the impact tool is selected as the adjustment mode by the mode adjustment mechanism, the rotational force of the motor is transmitted to the tip tool by the rotation transmission mechanism, and the rotation speed of the motor is set to the rotation speed of the adjustment mode lower than the normal operation mode. . Since the accessory tool rotates slowly in the adjustment mode, the operator can stop the accessory tool in an arbitrary direction and change the orientation of the favorite accessory tool. Thereby, the operativity and workability | operativity of an impact tool can be improved.

It is a longitudinal cross-sectional view which shows the impact tool of one embodiment of this invention in the state in which the hammer drill mode was selected. It is a top view of the mode selection dial shown by FIG. It is a longitudinal cross-sectional view which shows the impact tool of FIG. 1 in the state in which the hammer mode was selected. FIG. 4 is a plan view of the mode selection dial shown in FIG. 3. It is a longitudinal cross-sectional view which shows the impact tool of FIG. 1 in the state as which the adjustment mode was selected. (A) is a top view of the mode selection dial shown by FIG. 5, (B) is the 6B-6B sectional view taken on the line in (A). It is a perspective view which shows the cutter which is an example of a front-end tool. It is a longitudinal cross-sectional view which shows the impact tool of other embodiment of this invention in the state in which the adjustment mode was selected. (A) is a top view which shows the mode selection dial shown by FIG. 8, (B) is the 9B-9B sectional view taken on the line in (A). It is a longitudinal cross-sectional view which shows the impact tool of FIG. 8 in the state in which the neutral mode was selected. (A) is a top view of the mode selection dial shown by FIG. 9, (B) is the 11B-11B sectional view taken on the line in (A). It is a block diagram which shows the control circuit of an impact tool. It is a flowchart which shows the motor control algorithm which is an example of adjustment mode. It is a flowchart which shows the motor control algorithm which is another example of adjustment mode. It is a flowchart which shows the motor control algorithm which is another example of an adjustment mode.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, members having commonality are denoted by the same reference numerals, and redundant description is omitted.

The impact tool 10 shown in FIGS. 1 to 5 is also called a hammer drill, and the tip tool T is detachably attached as shown in FIG. As normal working modes by the striking tool 10, there are a hammer mode, that is, a striking mode, and a hammer drill mode, that is, a striking mode. The hammer mode is selected when an impact force is applied to the tip tool to perform a hole excavation work or a concrete chipping work on the work target. On the other hand, the hammer drill mode is selected when a rotational force and a striking force are applied to the tip tool to perform drilling or the like on the work target. The striking tool 10 has an adjustment mode in addition to the work mode described above. The adjustment mode is set when adjusting the rotation direction of the tip tool T.

As shown in FIG. 1, the impact tool 10 has a cylinder 11, and a cylindrical tool holder 12 is fixed to a tip portion of the cylinder 11 by a pin 13. The tool holder 12 is supported on the cylinder housing 14a via a bearing 15, and the cylinder 11 and the tool holder 12 are rotatably mounted in the cylinder housing 14a. When the cylinder 11 is rotated with the tip tool T mounted on the tool holder 12, the tip tool T is rotationally driven. In FIG. 1, only the base end portion of the tip tool T is shown.

The distal end portion of the hammer member 16 is incorporated in the proximal end portion of the tool holder 12 so as to be capable of reciprocating in the axial direction, and the proximal end portion of the hammer member 16 projects into the cylinder 11. A striking element 17 for applying an impact force to the hammer member 16 is mounted in the cylinder 11 so as to be reciprocally movable in the axial direction, and a piston 18 is reciprocally movable in the axial direction in the rear end portion of the cylinder 11. Installed. An air chamber 19 is provided between the striker 17 and the piston 18. When the piston 18 is driven forward, the air in the air chamber 19 is compressed and the striker 17 is driven in the forward direction. Thereby, the striker 17 collides with the hammer member 16, and the impact force of the striker 17 is applied to the tip tool T via the hammer member 16.

A tip cover 21 is attached to the cylinder housing 14a and constitutes a part of the cylinder housing 14a. A rubber tip cap 22 is attached to the tip of the tool holder 12. A grip 23 is attached to the outside of the tip cap 22 so as to be capable of reciprocating in the axial direction. A spring force in a direction away from the cylinder housing 14 a, that is, a forward direction, is urged by the coil spring 24. The tool holder 12 is fitted with an engagement roller that engages a groove provided in the tip tool T, that is, an engagement member 25 movably in the radial direction. A fastening ring 26 is provided on the grip 23, and as shown in FIG. 1, when the fastening ring 26 projects the engagement member 25 radially inward, the tip tool T is fastened to the tool holder 12. On the other hand, when the grip 23 is moved backward against the spring force, the engagement between the fastening ring 26 and the engagement member 25 is released. Under this state, when the tip tool T is pulled, the engaging member 25 is retracted radially outward, and the tip tool T can be removed. On the other hand, the tip tool T is inserted into the tool holder 12 with the grip 23 moved backward. When the tool holder 12 is moved forward by a spring force with the tip tool T inserted into the tool holder 12, the tip tool T is mounted on the tool holder 12 and fastened by the engaging member 25. The

A gear housing 14b is provided at the rear end of the cylinder housing 14a, and a motor housing 14c is provided in the gear housing 14b. The motor housing 14c is oriented substantially perpendicular to the cylinder housing 14a, and the housing 14 of the impact tool 10 is formed by these housings 14a to 14c. An operation handle 27 protrudes rearward from the rear portion of the housing 14, and a grip space 28 is provided between the operation handle 27 and the housing 14. The front cover 21 is provided with a side handle 29, but only a part of the side handle 29 is shown in FIG.

When an operator performs an operation with the impact tool 10, the operator usually holds the operation handle 27 and the side handle 29 with both hands so that the cylinder housing 14a is located above the motor housing 14c. The vertical relationship of the housing 14 indicates the posture in which the impact tool 10 is normally used, as shown in FIG. Further, the impact tool 10 has a tool holder 12 side as a front end portion and an operation handle 27 side as a rear end portion.

A motor 31 is accommodated in the motor housing 14c. The motor 31 is a brushless motor, and includes a cylindrical stator 32 around which a coil is wound, and a rotor 33 incorporated therein. An output shaft 34 is attached to the rotor 33, and the output shaft 34 faces a direction orthogonal to the reciprocating direction of the piston 18 in the cylinder 11 and outputs the rotational force of the motor 31. A base end portion of the output shaft 34 is rotatably supported by a bearing 35, and an output end portion of the output shaft 34 is rotatably supported by a bearing 36. The bearing 35 is incorporated in a retainer 37, and the retainer 37 is covered with a bottom cover 38 attached to the housing 14.

In order to convert the rotational force of the motor 31 into the impact force of the hammer member 16 and transmit the impact force to the tip tool T, an impact transmission mechanism 41 is provided in the housing 14. The impact transmission mechanism 41 includes a crankshaft 42 that is rotatably mounted in the housing 14 in parallel with the output shaft 34, and a large-diameter pinion gear 43 provided on the crankshaft 42 is a gear portion of the output shaft 34. Are engaged. An eccentric member 44 having a function as a crank weight is attached to the distal end portion of the crankshaft 42, and a crankpin 45 is attached to the eccentric member 44 at a position eccentric from the rotation center of the crankshaft 42. One end of a connecting rod 46 is rotatably fitted to the crank pin 45 and the other end is fitted to a piston pin 47 attached to the piston 18 so as to be swingable. Thereby, the rotational motion of the crankshaft 42 driven by the output shaft 34 is converted into the reciprocating motion of the piston 18 in the direction orthogonal to the output shaft 34 by the impact transmission mechanism 41 including the eccentric member 44 and the connecting rod 46. A striking force is applied to the hammer member 16.

In order to transmit the rotational movement of the output shaft 34 to the rotational movement of the tool holder 12, a rotation transmission mechanism 51 is provided in the housing 14. The rotation transmission mechanism 51 has a rotation transmission shaft 52 that is rotatably mounted in the housing 14 in parallel with the crankshaft 42, and has a large diameter pinion gear 54 that meshes with a small diameter pinion gear 53 provided on the crankshaft 42. Is provided on the rotation transmission shaft 52. An annular driven gear 55 is rotatably mounted on the outside of the cylinder 11, and this driven gear 55 meshes with a drive-side bevel gear 56 provided at the tip of the rotation transmission shaft 52.

A clutch sleeve 57 is fitted to the outside of the cylinder 11 so as to be movable in the axial direction, and a meshing portion 58 that meshes with the driven gear 55 is provided at the rear end portion of the clutch sleeve 57. A key member (not shown) is provided between the clutch sleeve 57 and the cylinder 11. When the clutch sleeve 57 is rotationally driven with the clutch sleeve 57 engaged with the driven gear 55, The rotation is transmitted to the cylinder 11 via the key member. Accordingly, the rotation transmission mechanism 51 including the rotation transmission shaft 52 driven by the output shaft 34 via the crankshaft 42, the driven gear 55, the clutch sleeve 57, and the like causes the rotational movement of the motor 31 to rotate the tool holder 12. Transmitted to movement.

As described above, the rotation transmission mechanism 51 decelerates the rotation speed of the output shaft 34 of the motor 31 with the three reduction gear pairs and transmits it to the rotation motion of the cylinder 11. The rotational speed of the output shaft 34 is reduced to a rotational speed of 1/36 and transmitted to the cylinder 11. However, the reduction ratio is arbitrarily set according to the type of the impact tool 10.

In order to bias the spring force in the direction toward the driven gear 55 against the clutch sleeve 57, a compression coil spring 59 is mounted in the cylinder housing 14a.

As shown in FIG. 1, when the motor 31 is driven in a state where the clutch sleeve 57 is engaged with the driven gear 55 by the spring force of the compression coil spring 59, the piston 18 and the cylinder 11 are driven to rotate. The impact tool 10 is driven in the hammer drill mode. On the other hand, as shown in FIG. 3, when the motor 31 is driven with the clutch sleeve 57 disengaged from the driven gear 55 against the spring force of the compression coil spring 59, the rotational force of the motor 31 is driven. Is transmitted only to the reciprocating motion of the piston 18 and no rotational force is transmitted to the cylinder 11, and the impact tool 10 is driven in the hammer mode. Further, as in the hammer drill mode, when the clutch sleeve 57 is engaged with the driven gear 55, the impact tool 10 is in the adjustment mode as shown in FIG. In the adjustment mode, the rotational force of the motor 31 is transmitted to the cylinder 11 and not transmitted to the piston 18.

A mode selection dial 61 is rotatably provided on the upper surface of the housing 14 in order to switch the striking tool 10 to any one of the above-described hammer drill mode, hammer mode, and adjustment mode. A mode selection dial 61 as an operation portion of the mode selection mechanism is rotatably mounted on a base plate 62 that forms a part of the housing 14, and an operation knob 63 of the mode selection dial 61 protrudes from the cover 64 to the outside. The mode selection dial 61 is provided with a cam pin 65, and the cam pin 65 is inserted into the cam hole of the cam member 66. The cam member 66 is moved in the front-rear direction into the housing 14 by the cam pin 65. The cam member 66 is attached to the rear end portion of the interlocking member 67 that extends in the front-rear direction of the housing 14 along the outside of the cylinder 11. The distal end portion of the interlocking member 67 is attached to a connecting portion 68 fixed to the clutch sleeve 57. Therefore, by rotating the mode selection dial 61 while holding the operation knob 63, the clutch sleeve 57 is switched between a position where the clutch sleeve 57 is engaged with the driven gear 55 and a position where the engagement is released.

As shown in FIG. 2, the mode of the impact tool operated by the mode selection dial 61 is displayed on the cover 64. The mode display is a hammer drill mode display portion 71a, a hammer mode display portion 71b, and an adjustment mode display portion 71c. When the mode selection dial 61 is rotated so that the operation knob 63 is aligned with the position of the hammer drill mode display portion 71a, the clutch sleeve 57 is driven by the interlocking member 67. Thereby, as shown in FIG. 1, the meshing portion 58 of the clutch sleeve 57 is meshed with the driven gear 55, that is, the rotation transmission mechanism 51 is in the rotation transmission state, and the impact tool 10 is switched to the hammer drill mode. On the other hand, as shown in FIG. 4, when the operation knob 63 is set to the position of the hammer mode display portion 71 b, the clutch sleeve 57 is driven by the interlocking member 67. As a result, as shown in FIG. 3, the meshing portion 58 of the clutch sleeve 57 is separated from the driven gear 55 against the spring force, that is, the rotation transmission mechanism 51 is switched to the transmission stop state, and further the clutch sleeve 57. The end portion on the end tool side is fitted with a rotation locking portion which is a part of the cylinder housing 14a, and the rotation of the cylinder 11 is restricted by the cylinder housing 14a, so that the impact tool 10 enters the hammer mode. The hammer mode display portion 71b is shifted by 180 degrees in the rotation direction of the mode selection dial 61 with respect to the hammer drill mode display portion 71a.

2 and 4, the position of the cam member 66 in the front-rear direction is constant regardless of whether the mode selection dial 61 is rotated clockwise or counterclockwise. Thereby, even if the mode selection dial 61 is rotated in any direction, either the hammer drill mode or the hammer mode can be set.

Further, as shown in FIG. 6, when the operation knob 63 is set to the position of the adjustment mode display portion 71c, the clutch sleeve 57 is driven by the interlocking member 67, and as shown in FIG. The portion 58 is engaged with the driven gear 55, that is, the rotation transmission mechanism 51 is in a rotation transmission state. Thereby, the impact tool 10 is in the adjustment mode. The adjustment mode display portion 71c is shifted by about 90 degrees with respect to the hammer drill mode display portion 71a and the hammer mode display portion 71b. As described above, even if the mode selection dial 61 is rotated to a position shifted by about 90 degrees in the rotation direction with respect to the hammer drill mode display portion 71a and the hammer mode display portion 71b, the cam pin 65 is engaged with the cam member 66. Depending on the shape of the cam hole, the position of the clutch sleeve 57 in the front-rear direction is set to a position meshed with the driven gear 55 as in the hammer drill mode.

Two adjustment mode display portions 71c are provided at positions shifted 90 degrees clockwise and counterclockwise with respect to the hammer drill mode display portion 71a and the hammer mode display portion 71b. Regardless of the position of the mode selection dial 61, the position of the cam member 66 in the front-rear direction is the same, and the adjustment mode is set. When the adjustment mode is selected, the motor 31 is rotated at a speed lower than the rotation speed in the normal work mode. In the adjustment mode, as shown in FIG. 7, the rotational direction of the cutting edge E of the tip tool T can be automatically and slowly adjusted from the position indicated by the solid line to the direction indicated by the broken line, for example. . Thus, the operator can easily adjust the tip tool T to a desired position by observing the tip tool that rotates slowly and stopping the motor 31 at an arbitrary position. Next, the operation knob 63 is displayed in the hammer mode. By matching with the position of the portion 71b, the operator can perform the chiseling work (work in the hammer mode) at the position of the favorite tip tool.

At this time, since the engagement between the clutch sleeve 57 and the rotation locking portion 60 can be performed in increments of 30 °, the operator can adjust the tip tool in 12 stages of angles. The engagement between the clutch sleeve 57 and the rotation locking portion 60 is considered in 30 ° increments by enabling the cylinder 11 to be locked to the cylinder housing 14a in at least 90 ° increments. This is because adjustment is possible. As described above, since the rotational position of the tip tool can be adjusted in increments of a predetermined amount (predetermined angle), for example, the tip tool can be accurately rotated by 90 °.

A ball 69 is incorporated in the base of the mode selection dial 61, and a spring force in a direction toward the base plate 62 is urged by the spring member. The base plate 62 is provided with a V-shaped engagement groove at a position corresponding to each of the mode display portions 71a to 71c, and the ball 69 is engaged when the mode selection dial 61 is operated to any mode position. Entering the mating groove, a resistance force in the rotational direction due to the spring force is applied to the mode selection dial 61. This prevents the mode selection dial 61 from rotating carelessly.

In order to detect the mode selected by operating the mode selection dial 61, the mode selection dial 61 is provided with a magnetic body 72, as shown in FIG. 6B. A mode detection sensor 73 composed of a magnetic sensor sensitive to the magnetism of the magnetic body 72 is provided on the base plate 62 as a mode detection means corresponding to each of the mode display portions 71a to 71c. Four mode detection sensors 73 are provided on the base plate 62 in correspondence with the hammer drill mode display portion 71a, the hammer mode display portion 71b, and the two adjustment mode display portions 71c.

The motor 31 is driven by a commercial power source, and a power supply cable 74 is attached to the operation handle 27. FIG. 1 shows only a part of the power supply cable 74, and a plug (not shown) is provided at the tip of the power supply cable 74. A trigger 75 is provided on the operation handle 27 in order to switch between a state in which the motor 31 is driven and a state in which the motor 31 is stopped. When the trigger 75 is operated, a trigger switch as a motor start switch, that is, a main switch 75a is turned on / off.

The hammer drill mode and the hammer mode are normal work modes, and the rotation speed of the motor 31 in the normal work mode is switched to a plurality of stages according to the type of work. In order to set the rotational speed of the motor, as shown in FIG. 1, a speed setting button 77 is mounted as a speed setting means on an operation panel 76 provided on the housing 14 so as to face the operation handle 27. In the impact tool 10, the motor rotation speed in the normal work mode can be set in four stages. The first speed is about 8000 rpm, the second speed is about 11000 rpm, the third speed is about 14000 rpm, and the fourth speed is about 17000 rpm. The speed setting button 77 may be a single speed setting button, or four speed setting buttons may be provided corresponding to the rotation speeds from the first speed to the fourth speed. When one speed setting button 77 is used, each time the speed setting button 77 is pressed once, the rotational speed is sequentially increased toward the high speed stage. When the speed setting button 77 is operated under the state set to the fourth speed, the speed is returned to the first speed.

On the other hand, when the adjustment mode is selected, the motor rotation speed is set to about 200 rpm. This speed is 1/40 of the rotational speed of the first speed in the normal work mode. The board 78 provided in the housing 14 is provided with a motor control unit for adjusting the rotation speed of the motor 31.

FIG. 8 is a longitudinal sectional view showing an impact tool according to another embodiment of the present invention in a state where the adjustment mode is selected. 9A is a plan view showing the mode selection dial shown in FIG. 8, and FIG. 9B is a sectional view taken along line 9B-9B in FIG. 9A. FIG. 10 is a longitudinal sectional view showing the striking tool of FIG. 8 in a state where the neutral mode is selected. 11A is a plan view of the mode selection dial shown in FIG. 9, and FIG. 11B is a sectional view taken along line 11B-11B in FIG. 11A.

The impact tool 10 shown in FIGS. 8 to 11 includes a neutral mode in addition to the hammer drill mode, the hammer mode, and the adjustment mode described above. As shown in FIGS. 9 and 11, the cover 64 displays a hammer drill mode display portion 71a, a hammer mode display portion 71b, an adjustment mode display portion 71c, and a neutral mode display portion 71d. The mode can be switched to any of these modes by rotating the selection dial 61.

When the operation knob 63 of the mode selection dial 61 is set to the position of the hammer drill mode display portion 71a, the engagement tool 58 of the clutch sleeve 57 is moved to the driven gear 55 in the same manner as shown in FIGS. After meshing, the rotation transmission mechanism 51 enters a rotation transmission state and is switched to the hammer drill mode. Further, when the operation knob 63 is set to the position of the hammer mode display portion 71b, the hitting tool 10 is rotated as the meshing portion 58 of the clutch sleeve 57 is separated from the driven gear 55 as in the case shown in FIGS. The transmission mechanism 51 is in a transmission stop state, and the end portion on the tip tool side of the clutch sleeve 57 and the rotation locking portion 60 are fitted to be switched to the hammer mode.

On the other hand, when the operation knob 63 of the mode selection dial 61 is set to the position of the adjustment mode display portion 71c, the striking tool 10 is switched to the adjustment mode as shown in FIGS. When the mode is switched to the adjustment mode, the meshing portion 58 of the clutch sleeve 57 is meshed with the driven gear 55 as shown in FIG. At this time, the rotation transmission mechanism 51 is in a rotation transmission state as in the hammer drill mode.

Further, when the operation knob 63 is set to the position of the neutral mode display portion 71d, the impact tool 10 is switched to the neutral mode as shown in FIGS. When the neutral mode is selected, as shown in FIG. 10, the meshing portion 58 of the clutch sleeve 57 is separated from the driven gear 55, the rotation transmission mechanism 51 is in a transmission stop state, and the rotational force of the motor 31 is applied to the tip tool T. Transmission is interrupted, and the end of the clutch sleeve 57 on the end tool side does not fit into the rotation locking portion 60. As a result, the tip tool T is idled, and the orientation of the tip tool T can be adjusted manually.

Thus, in the impact tool 10 provided with the adjustment mode and the neutral mode in addition to the normal work mode, the shape of the cam hole formed in the cam member 66 has the impact tool shown in FIGS. 10 and different. A total of six mode detection sensors 73 are provided on the base plate 62 of the impact tool 10. In the impact tool shown in FIGS. 8 to 11, except for the shape of the mode selection dial 61 and the cam member 66, other structures are substantially the same as those of the impact tool 10 shown in FIGS. 1 to 6. .

As the mode selection means, instead of the rotary mode selection dial 61, a push button type or a knob type that linearly reciprocates may be used. Further, the speed setting means described above may be a rotary speed setting dial or a linearly reciprocating knob type instead of the push button type speed setting button 77.

FIG. 12 is a block diagram showing a control circuit of the impact tool. The stator 32 of the motor 31 includes coils U1, V1, and W1 corresponding to the U phase, the V phase, and the W phase. On the other hand, the rotor 33 is provided with two types of permanent magnets having different polarities. These four permanent magnets are arranged at equal intervals along the rotation direction of the rotor 33. Three magnetic sensors S1, S2 and S3 are arranged in the vicinity of the rotor 33. These magnetic sensors S 1, S 2, S 3 detect a magnetic force change accompanying the rotation of the rotor 33 and output an electric signal to the rotor position detection circuit 81. Hall elements are used for the magnetic sensors S1, S2, and S3 in the present embodiment.

The switching circuit 82 controls energization to the coils U1, V1, W1 of the stator 32. The commercial power supplied from the outside by the power supply cable 74 is converted into a direct current by the rectifier circuit 83. The direct current output from the rectifier circuit 83 is boosted by the power factor correction circuit 84 and supplied to the switching circuit 82. The rectifier circuit 83 is a bridge circuit in which four diode elements are connected to each other. The power factor correction circuit 84 includes a field effect transistor, an integrated circuit that outputs a PWM (Pulse Width Modulation) control signal to the field effect transistor, and a capacitor, and limits a high-frequency current generated in the switching circuit 82. Suppress below the value.

The switching circuit 82 is a three-phase full-bridge inverter circuit, and includes two switching elements Tr1 and Tr2 connected in parallel, two switching elements Tr3 and Tr4 connected in parallel, and two switching elements Tr5 and 5 connected in parallel. Tr6. Each switching element is an insulated gate bipolar transistor (IGBT). The switching elements Tr1 and Tr2 are connected to the coil U1 and control the current supplied to the coil U1. The switching elements Tr3 and Tr4 are connected to the coil V1 and control the current supplied to the coil V1. The switching elements Tr5 and Tr6 are connected to the coil W1 and control the current supplied to the coil W1.

The switching elements Tr1, Tr3, Tr5 are connected to the positive output terminal of the power factor improvement circuit 84, and the switching elements Tr2, Tr4, Tr6 are connected to the negative output terminal of the power factor improvement circuit 84. That is, the switching elements Tr1, Tr3, Tr5 are on the high side, and the switching elements Tr2, Tr4, Tr6 are on the low side.

In the illustrated embodiment, the coils U1, V1, W1 are star-connected. However, the connection method of the coils U1, V1, and W1 is not limited to star connection, and may be, for example, delta connection.

The motor control unit 86 includes a controller 87 as a control unit, a control signal output circuit 88, a rotor position detection circuit 81, and a motor rotation number detection circuit 85. The controller 87 calculates and outputs a signal for controlling the motor 31. A control signal output from the controller 87 is input to the switching circuit 82 via the control signal output circuit 88. The rotor position detection circuit 81 detects the rotational position of the rotor 33 based on the electrical signals output from the magnetic sensors S1, S2, and S3, and outputs a signal indicating the rotational position of the rotor 33. The position detection signal output from the rotor position detection circuit 81 is input to the controller 87 and the motor rotation speed detection circuit 85. The motor rotation speed detection circuit 85 detects the rotation speed of the rotor 33, that is, the motor rotation speed, and outputs a signal indicating the motor rotation speed. A rotation speed detection signal output from the motor rotation speed detection circuit 85 is input to the controller 87. The controller 87 performs feedback control based on the rotation speed detection signal so that the motor rotation speed is maintained at the target rotation speed.

The controller 87 receives an on signal and an off signal output from the main switch 75 a in accordance with the operation of the trigger 75. When the trigger 75 is operated by an operator, an on signal or an off signal is output from the main switch 75a according to the operation. Specifically, when the trigger 75 is pulled, an on signal is output from the main switch 75a, and when the trigger 75 is released, an off signal is output from the main switch 75a, or the output of the on signal is stopped. When the controller 87 receives the ON signal output from the main switch 75a, the controller 87 determines that the main switch 75a is turned ON. On the other hand, the controller 87 determines that the main switch 75a is turned off when it receives the off signal output from the main switch 75a or stops receiving the on signal.

A signal from the mode detection sensor 73 is sent to the controller 87, and the mode selected by operating the mode selection dial 61 is detected. When the adjustment mode is selected by operating the mode selection dial 61, the rotation speed of the motor 31 is set to an adjustment mode rotation speed that is lower than the rotation speed in the normal work mode. The rotation speed in the normal work mode is selected by operating a speed setting button 77 provided on the operation panel 76. The operation panel 76 is provided with an LED 79 for displaying a color corresponding to the selected motor rotation speed. The mode selected by operating the mode selection dial 61 may be lit on the operation panel 76. The controller 87 includes a memory that stores a control program, map data, and the like, and a microprocessor that calculates control signals. The four-stage motor rotation speed data in the normal operation mode and the adjustment mode rotation speed data of the motor 31 in the adjustment mode are stored in the memory.

There are various forms of motor drive control for changing the direction of the tip tool when the adjustment mode is selected. For example, as a first control mode, there is a continuous rotation type in which the motor 31 is continuously driven only while the trigger 75 is operated. Further, as a second control mode, there is a fixed amount rotation type in which the motor 31 is rotated by a fixed time, that is, a fixed angle when the trigger 75 is operated once. Further, as a third control mode, there is a repetitive operation formula in which the rotation time, that is, the rotation angle of the motor 31 is changed at the adjustment mode rotation speed in accordance with the number of operations of the trigger 75. As described above, the adjustment mode rotation speed is set to a rotation speed lower than that of the normal operation mode, for example, about 200 rpm.

FIG. 13 is a flowchart showing a continuous rotation type motor control algorithm which is a first control mode when the adjustment mode is selected.

When the operator operates the mode selection dial 61 to set the operation knob 63 to the position of the adjustment mode display portion 71c, the mode detection sensor 73 outputs a detection signal to the controller 87. When the detection signal is determined in step S1, the rotation speed of the motor 31 is set to the adjustment mode rotation speed of 200 rpm in step S2. Under this state, when the trigger 75 is operated by the operator and the main switch 75a outputs an ON signal, the motor 31 is driven at the adjustment mode rotation speed (steps S3 and S4). If it is detected in step S5 that the main switch 75a is turned off, the rotation of the motor 31 is stopped (step S6).

In step S7, it is determined whether or not the mode selection dial 61 is set in the adjustment mode display portion 71c. If the mode selection dial 61 remains set in the adjustment mode, the process returns to step S3 again. If the main switch 75a is off in step S3, the rotational speed of the motor is set to the rotational speed of the normal work mode in step S8. The rotation speed in the normal work mode is set to any one of the first speed to the fourth speed input by operating the speed setting button 77 as described above.

As described above, according to the first control mode, the motor 31 is continuously driven at a low speed until the cutting edge E of the tip tool T is desired until the main switch 75a as the motor start switch is turned on and then turned off. The direction of the tip tool T is adjusted by returning the trigger 75. For example, in FIG. 7, the orientation of the cutting edge E is automatically adjusted from the state in which the cutting edge E of the tip tool T before starting work is directed in the direction indicated by the solid line to the direction indicated by the broken line. Thereby, the operator can easily change the direction of the cutting edge of the tip tool T, and the workability of the impact tool 10 can be improved.

FIG. 14 is a flowchart showing a constant amount rotation type motor control algorithm as a second control mode when the adjustment mode is selected.

In FIG. 14, steps S11 and S12 correspond to steps S1 and S2 in FIG. 13, and when the adjustment mode is selected by the operator, the rotation speed of the motor 31 is set to the adjustment mode rotation speed of 200 rpm. (Steps S11 and S12). Under this state, when the trigger 75 is operated and the main switch 75a outputs an ON signal, the motor 31 is driven by three rotations (step S13). When the output shaft 34 of the motor 31 is driven three times, the output shaft 34 is decelerated to a rotational speed of 1/36 by the rotation transmission mechanism 51 and transmitted to the tool holder 12 as described above. The direction of the rotation direction of the tool T is adjusted by 30 degrees.

In step S15, it is determined whether or not the mode selection dial 61 is set in the adjustment mode display portion 71c. If the mode selection dial 61 remains set in the adjustment mode, the process returns to step S13 again. If it is determined in step S13 that the main switch 75a is off, in step S16, the rotational speed of the motor is set to the rotational speed of the normal work mode. As described above, in the second control mode shown in FIG. 14, when the trigger 75 is operated once, the motor 31 is driven to rotate for a certain time, that is, a certain number of rotations. For example, in FIG. 7, the direction of the cutting edge E is automatically adjusted by 30 degrees in the direction indicated by the broken line from the state where the cutting edge E of the tip tool T before starting the work is directed in the direction indicated by the solid line. Thereby, the operator can easily change the direction of the cutting edge of the tip tool T, and the workability of the impact tool 10 can be improved.

When the trigger 75 is operated once, the time during which the motor 31 is rotationally driven, that is, the total number of rotations is not limited to the above-described three rotations, and can be any number of rotations. For example, if there are two rotations, when the trigger 75 is operated once, the tip tool T changes its direction by 20 degrees.

FIG. 15 is a flowchart showing a repetitive operation motor control algorithm as a third control mode when the adjustment mode is selected.

In FIG. 15, steps S21 and S22 correspond to steps S1 and S2 of FIG. 13, and when the adjustment mode is selected by the operator, the rotation speed of the motor 31 is set to the adjustment mode rotation speed of 200 rpm. (Steps S21 and S22). When the adjustment mode is selected, control for detecting the number of times the motor 31 is rotationally driven is started in step S23. When the trigger 75 is operated in this state, the motor 31 is driven, and when the trigger 75 is turned off, the number of operations of the trigger 75 is counted (steps S24 to S27). The motor 31 is driven three times for each count. When the motor 31 is driven three times, as shown in FIG. 14, the direction of the rotation direction of the tip tool T is adjusted by 30 degrees. Therefore, for example, when the trigger 75 is turned on twice, the direction of the tip tool T in the rotation direction of 60 degrees is adjusted.

When the direction of the tip tool T is adjusted by an angle corresponding to the counted number, the motor 31 is stopped in step S29, and the counter is reset. In step S30, even if the orientation adjustment of the tip tool T is completed, if the adjustment mode is not released, the process returns to step S24. If it is determined in step S28 that the number of adjustments input has not been completed, the drive of the motor 31 is continued in step S31. When the adjustment for the input number of times is completed and the mode selection dial 61 is operated to cancel the adjustment mode, the rotation speed is set to the normal work mode (step S32). Thereby, the operator can easily change the direction of the cutting edge of the tip tool T, and the workability of the impact tool 10 can be improved.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, as described above, the motor 31 is driven when the trigger 75 is operated when either the normal work mode or the adjustment mode is selected, but the adjustment mode is selected. Under the state, a motor driving switch for driving the motor 31 may be provided and used as a motor start switch. In that case, the trigger 75 is used to drive the motor 31 only when the normal work mode is selected. Further, although the fitting angle between the clutch sleeve 57 and the rotation locking portion 60 is 12 steps, the fitting angle may be 24 steps with the fitting angle being incremented by 15 °. In that case, the operator can make finer adjustments and workability is improved.

DESCRIPTION OF SYMBOLS 10 ... Blow tool, 11 ... Cylinder, 12 ... Tool holder, 14 ... Housing, 16 ... Hammer member, 17 ... Strike element, 18 ... Piston, 19 ... Air chamber, 23 ... Grip, 24 ... Coil spring, 25 ... Engagement Coupling member, 26 ... fastening ring, 27 ... operation handle, 31 ... motor, 34 ... output shaft, 41 ... impact transmission mechanism, 42 ... crankshaft, 43 ... pinion gear, 44 ... eccentric member, 51 ... rotation transmission mechanism, 52 ... Rotation transmission shaft, 55 ... driven gear, 56 ... bevel gear, 57 ... clutch sleeve, 58 ... meshing part, 59 ... compression coil spring, 60 ... rotation locking part, 61 ... mode selection dial, 62 ... base plate, 63 ... operation Knob, 64 ... cover, 65 ... cam pin, 66 ... cam member, 67 ... interlocking member, 71a ... hammer drill mode display, 71b ... hammer mode display, 71c ... adjustment mode De display unit, 71d ... neutral mode display unit, 72 ... magnetic, 73 ... mode detecting sensor, 75 ... trigger, 75a ... main switch, 76 ... operation panel, 77 ... speed setting button, 87 ... controller.

Claims (8)

A motor housed in a housing; a rotation transmission mechanism that transmits a rotational force of the motor to a tip tool; a striking transmission mechanism that converts the rotational force of the motor into a striking force and transmits the striking force to the tip tool; and the rotation transmission A striking tool having a mode selection mechanism that switches the mechanism between a rotation transmission state and a transmission stop state, and a control unit that controls the driving of the motor, wherein the mode selection mechanism is a direction of the rotation direction of the tip tool. The striking tool includes an adjustment mode for adjusting the motor, and the control unit drives the rotation speed of the motor at an adjustment mode rotation speed lower than that of the normal operation mode when the adjustment mode is selected. The impact tool according to claim 1, wherein the mode selection mechanism has a neutral mode that blocks transmission of the rotational force of the motor to the tip tool. The said mode selection mechanism has the hammer drill mode which transmits rotational force and a striking force to the said tip tool, and the hammer mode which transmits only a striking force to the said tip tool as said normal operation mode. Blow tool. The said control part is a striking tool of any one of Claims 1-3 which has the mode detection means to detect the mode selected by the said mode selection mechanism. The mode selection mechanism includes an operation unit that includes a magnetic body and is movably provided on the housing. The mode detection unit is a magnetic sensor that is sensitive to magnetism of the magnetic body. The impact tool according to claim 4, wherein the rotation speed of the motor is controlled based on a detection signal. 6. A motor start switch for turning on and off the motor, and when the adjustment mode is selected, the motor is driven at the adjustment mode rotation speed until the motor start switch is turned off. The impact tool according to claim 1. The motor according to any one of claims 1 to 5, further comprising a motor start switch for turning on and off the motor, wherein when the adjustment mode is selected, the tip tool is rotated by a certain angle when the motor start switch is turned on. The hitting tool described. 6. The motor according to claim 1, further comprising a motor start switch for turning on and off the motor, wherein when the adjustment mode is selected, the tip tool is rotated by an angle corresponding to the number of operations of the motor start switch. The hitting tool described in 1.

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