JP6600960B2 - Reciprocating tool - Google Patents

Description

  The present invention relates to a reciprocating tool in which the rotational force of a motor is transmitted to a tip tool and the tip tool reciprocates.

  A reciprocating tool is known in which a biting force is applied to a tip tool such as a bit, and a concrete wall or a concrete floor is crushed by the bit. Drilling is performed by applying a rotational force to the tip tool in addition to the hitting force. A reciprocating tool for performing work is generally called a hammer drill.

  Many of the conventional hammer drills have at least two operation modes, for example, a hammer mode in which only the striking force is transmitted to the bit and a hammer drill mode in which both the striking force and the rotational force are transmitted to the bit. In the conventional hammer drill having a plurality of operation modes as described above, when the trigger lever is operated by the operator, the necessary power is transmitted to the bit according to the selected operation mode.

Japanese Patent No. 4281273

  The hammer drill having the hammer drill mode and the hammer mode has a configuration capable of switching the rotation direction of the motor in order to reverse the rotation of the bit for the purpose of facilitating extraction of the bit from the object in the hammer drill mode. .

  Since the bit rotates in hammer drill mode, the operator can recognize the direction of motor rotation. However, when working in hammer mode with the motor rotation set to reverse rotation, the motor rotation Since the striking force is transmitted to the bit regardless of the direction, the operator cannot recognize the rotation direction of the motor.

  Even in the case of the reciprocating tools such as hammers, jigsaws, saversaws, clippers, etc., in which the rotational force of the motor is transmitted to the tip tool and the tip tool reciprocates, the motor rotation is not limited to the above-described hammer drill. The direction could not be recognized.

  For this reason, the reciprocating tool is continuously used in a reverse rotation state in which the motor is in an undesired rotational direction because of a structure, and there is a case where a problem occurs in the product life.

  An object of the present invention is to provide a reciprocating tool capable of performing appropriate motor control in accordance with the rotation direction of the motor or the state of switching of the rotation direction to improve the life.

The purpose is to transmit the motor, the rotational force of the motor, the tip tool capable of cutting the mating material by reciprocating, the control unit for controlling the drive of the motor, and the worker for turning the motor on and off. A reciprocating tool including a trigger operated by the operator and a rotation direction switching means operated by an operator to switch the rotation direction of the motor between forward rotation and reverse rotation. When it is determined that the state of the rotation direction switching means is reverse rotation, the motor is controlled in a limit mode, and the control unit drives the motor when the trigger is turned on in the limit mode. In addition, even if the trigger on operation is maintained, the motor is stopped when a predetermined stop condition is satisfied, and when the trigger is turned on in a state other than the limit mode, the motor is stopped. Drives the motor, can be achieved by a structure for maintaining the driving of the motor regardless of whether the said trigger ON operation is maintained for a predetermined stop condition is satisfied.

  ADVANTAGE OF THE INVENTION According to this invention, the reciprocating tool which can perform suitable motor control according to the rotation direction of a motor and can aim at lifetime improvement etc. can be provided.

Sectional drawing which shows the hammer drill which is one Example of the reciprocating tool of this invention. Sectional drawing which shows the state from which the operation mode was switched from the state of FIG. The block diagram of the hammer drill of FIG. The principal part enlarged view which shows an example of the fan used for the hammer drill of FIG. The principal part enlarged view which shows an example of the pinion gear used for the hammer drill of FIG. The principal part enlarged view which shows an example of the 1st gear used for the hammer drill of FIG. The flowchart which shows an example of the motor control used for the hammer drill of FIG. The table | surface which shows an example of Duty control used by the motor control of FIG. The flowchart which shows the 2nd Example of the reciprocating tool of this invention. The flowchart which shows the 3rd Example of the reciprocating tool of this invention.

  Hereinafter, a first embodiment of the reciprocating tool of the present invention will be described. The reciprocating tool according to the present embodiment is a hammer drill that can attach and detach a bit that is an example of a tip tool. Although the use of the hammer drill according to the present embodiment is not particularly limited, it is suitable for an operation of making a hole in an object such as a concrete wall or a stone or crushing the object. In addition, the hammer drill according to the present embodiment has a hammer mode in which a striking force is transmitted to the bit while a rotational force is not transmitted, and a drill mode in which at least the rotational force is transmitted to the bit. Further, in the drill mode in the present embodiment, the striking force is transmitted to the bit in addition to the rotational force.

  As shown in FIG. 1, the hammer drill 1 includes a cylinder housing 2, an intermediate housing 3, a motor housing 4, and a handle 5, which are fixed and integrated with each other. The cylinder housing 2 has a cylindrical shape as a whole, and an intermediate housing 3 and a motor housing 4 are disposed between one end (rear end) in the longitudinal direction of the cylinder housing 2 and the handle 5. The intermediate housing 3 and the motor housing 4 overlap each other vertically, one end (lower end) of the handle 5 is connected to the motor housing 4, and the other end (upper end) of the handle 5 is connected to the intermediate housing 3. The handle 5, the intermediate housing 3, and the motor housing 4 are connected to each other via a vibration isolation mechanism.

  A cylindrical cylinder 10 and a retainer sleeve 11 are accommodated in the cylinder housing 2. The cylinder 10 and the retainer sleeve 11 are concentric, and a part of the retainer sleeve 11 protrudes from the tip of the cylinder housing 2. The cylinder 10 and the retainer sleeve 11 are engaged so as not to rotate relative to each other. When a rotational force is transmitted to the cylinder 10, the cylinder 10 and the retainer sleeve 11 rotate integrally with the central axis as a rotation axis. A part of the bit (not shown) is inserted into the retainer sleeve 11. The bit inserted into the retainer sleeve 11 engages with the retainer sleeve 11 so as not to move in the rotational direction and to move within a predetermined range in the axial direction. Therefore, when the cylinder 10 and the retainer sleeve 11 rotate, the rotational force is transmitted to the bit, and the bit rotates. Further, when the impact force is transmitted to the bit, the bit reciprocates within a predetermined range in the axial direction. Details of the movement of the cylinder 10, the retainer sleeve 11, and the bit will be described later.

  A piston 20 and a striker 21 are accommodated in the cylinder 10 so as to be able to reciprocate. Further, the intermediate element 22 is accommodated so as to be able to reciprocate across the cylinder 10 and the retainer sleeve 11. The piston 20, the striker 21 and the intermediate element 22 are arranged in a line in this order from the rear to the front of the cylinder 10. Further, an air chamber 23 is provided in the cylinder 10 between the piston 20 and the striker 21.

  A motor 30 as a power source is accommodated in the motor housing 4. The motor 30 is an inner rotor type brushless motor, and includes a cylindrical stator 31, a rotor 32 disposed inside the stator 31, and an output shaft 33 disposed inside the rotor 32. The output shaft 33 is fixed to the rotor 32 and extends vertically through the rotor 32. The central axis of the output shaft 33 and the central axes of the cylinder 10 and the retainer sleeve 11 are orthogonal to each other.

  The upper part of the output shaft 33 protruding from the rotor 32 penetrates the partition wall between the motor housing 4 and the intermediate housing 3 and enters the inside of the intermediate housing 3. A pinion gear 34 is provided at the upper end of the output shaft 33 protruding into the intermediate housing 3.

  A fan 35 located above the stator 31 is attached to the rotor 32 so as to rotate integrally. As shown in FIG. 4, the fan 35 has a plurality of blades 36. When the brushless motor rotates normally, that is, when the rotor 32 rotates normally, the fan 35 rotates in the counterclockwise direction shown in the figure. Rotate. The blade 36 has an inclined shape in which the blade shape gradually separates in the clockwise direction with respect to the radial direction as it goes radially outward, and the motor housing 4 is effectively effective when the rotor 32 rotates forward. A fan wind is generated inside.

  The fan wind generated by the rotation of the fan 35 flows into the motor housing 4 from the lower side of the motor housing 4, passes through the periphery of the rotor 32 and the stator 31, and is discharged to the outside from the radially outer side of the fan 35. Further, the fan wind also passes through the vicinity of the control board 100 described later, flows to the inside of the fan 35, and also flows to the outside from the radially outer side of the fan 35.

  As described above, the fanless air generated by the rotation of the fan 35 cools the brushless motor 30 and the control board 100 that controls the driving of the brushless motor 30.

  The fan 35 generates a fan wind even when the rotor 32 rotates in the reverse direction. However, as described above, the fan 35 has a shape that effectively generates the fan wind during the normal rotation, and the rotor 32 is reversed. When rotating, the fan air flow is reversed and the fan air in the motor housing 4 is discharged from the lower side of the motor housing 4, or the fan air flow rate decreases while the fan air flow direction is maintained. Is done.

  In the intermediate housing 3, the first drive shaft 40 is rotatably disposed in the vicinity of the output shaft 33, and the second drive shaft 50 is rotatably disposed in the vicinity of the first drive shaft 40. . The output shaft 33, the first drive shaft 40, and the second drive shaft 50 are parallel to each other.

  A first gear 41 that meshes with the pinion gear 34 is provided at the lower portion of the first drive shaft 40, and an eccentric pin 42 is provided at the upper portion of the first drive shaft 40, and the eccentric pin 42 is connected via a connecting rod 43. Are connected to the piston 20.

  The teeth of the pinion gear 34 and the first gear 41 are inclined with respect to the output shaft 33 and the first drive shaft 40 as shown in FIGS. Thus, by making the tooth part into the inclined shape, the contact area between the tooth parts can be increased, and the life of the pinion gear 34 and the first gear 41 is extended.

  As shown in FIG. 5, when the brushless motor 30 is rotated forward, that is, when the rotor 32 is rotated forward, the output shaft having the pinion gear 34 is engaged by the engagement of the tooth portion of the pinion gear 34 and the tooth portion of the first gear 41. 33, the load acts on the upper side as shown by the dotted arrow in the figure, and the first gear 41 and the first drive shaft 40 are on the lower side as shown by the dotted arrow in the opposite direction as shown in FIG. The load will work. 5 and 6 indicate the rotation direction of the pinion gear 34 and the first gear 41 when the rotor 32 rotates forward and backward, and the dotted arrow indicates the load acting when the rotor 32 rotates forward and reverse. Indicates direction.

  When the rotor 32 rotates in the reverse direction, the load on the lower side is applied to the output shaft 33 and the upper load is applied to the first gear 41 and the first drive shaft 40, contrary to the case of normal rotation.

  A second gear 51 that meshes with the first gear 41 is provided at the lower portion of the second drive shaft 50, and a bevel gear 52 is provided at the upper portion of the second drive shaft 50. The bevel gear 52 is disposed around the cylinder. Is engaged with a ring gear 53 disposed on the surface. The ring gear 53 is mounted on the outer peripheral surface of the cylinder 10 via a sliding bearing (metal) and rotates freely with respect to the cylinder 10.

  In addition to the ring gear 53, a sleeve 54 is provided on the outer peripheral surface of the cylinder 10. The sleeve 54 rotates integrally with the cylinder 10 and slides back and forth in the axial direction of the cylinder 10 alone. The sleeve 54 is always biased by the spring 55 in the direction approaching the ring gear 53.

  A mode switching dial 60 is provided on the upper surface of the intermediate housing 3. The hammer mode and the hammer drill mode are switched by rotating the mode switching dial 60. In other words, a rotational transmission operation of the mode switching dial 60 selectively forms a power transmission path for transmitting only the striking force to the bit and a power transmission path for transmitting the striking force and the rotational force to the bit. . Details of the power transmission path will be described later.

  When the mode switching dial 60 shown in FIG. 1 is rotated 180 degrees in the first direction, the operation arm 61 moves forward in the axial direction of the cylinder 10 as shown in FIG. Then, the sleeve 54 is pushed by the operating arm 61 that moves forward, and the sleeve 54 slides forward against the bias of the spring. As a result, the engagement between the ring gear 53 and the sleeve 54 is released. When the engagement between the ring gear 53 and the sleeve 54 is released in this way, the transmission of the rotational force to the cylinder 10 is interrupted.

  On the other hand, when the mode switching dial 60 shown in FIG. 2 is rotated 180 degrees in the second direction, the operation arm 61 moves backward as shown in FIG. Then, the contact between the operation arm 61 and the sleeve 54 is released, and the sleeve 54 slides backward by the bias of the spring. As a result, the ring gear 53 and the sleeve 54 are engaged. When the ring gear 53 and the sleeve 54 are engaged in this manner, a rotational force is transmitted to the cylinder 10.

  As shown in FIGS. 1 and 2, the handle 5 is provided with a trigger lever 70 operated by an operator and a rotation direction switching button 80 operated by the operator. The rotation direction switching button 80 corresponds to the rotation direction switching means of the present invention. In addition, a trigger switch 71 that is turned on / off based on an operation of the trigger lever 70 is provided inside the handle 5. The rotation direction switching button 80 incorporates a lighting unit 81 (LED in the present embodiment) that is lit when the rotation direction of the brushless motor 30 is reversed by the rotation direction switching button 80. Further, the handle 5 is also provided with an operation panel 90 including a speed setting button and a plurality of LEDs. When the speed setting button on the operation panel 90 is pressed, the speed of the brushless motor 30 is switched stepwise according to the number of times. In addition, the number of LEDs that are lit changes according to the set speed, and the set speed is notified.

  Next, the power transmission path in the hammer drill 1 will be described. When the brushless motor 30 shown in FIGS. 1 and 2 operates, the rotation of the output shaft 33 is transmitted to the first drive shaft 40 via the pinion gear 34 and the first gear 41, and the first drive shaft 40 rotates. The rotation of the output shaft 33 is transmitted to the second drive shaft 50 via the pinion gear 34, the first gear 41, and the second gear 51, and the second drive shaft 50 rotates.

  When the first drive shaft 40 rotates, the eccentric pin 42 provided at the upper end of the first drive shaft 40 rotates with the central axis of the first drive shaft 40 as the rotation axis. That is, the eccentric pin 42 turns around the central axis of the first drive shaft 40. As a result, the piston 20 connected to the eccentric pin 42 via the connecting rod 43 reciprocates in the cylinder 10. When the piston 20 moves in a direction away from the striker 21, that is, when the piston 20 moves backward, the pressure in the air chamber 23 decreases and the striker 21 moves backward. On the other hand, when the piston 20 moves in the direction approaching the striker 21, that is, when the piston 20 moves forward, the pressure in the air chamber 23 rises and the striker 21 moves forward. When the striker 21 moves forward, the intermediate piece 22 is hit by the striker 21 and a bit (not shown) is hit by the intermediate piece 22. In this way, the striking force is intermittently transmitted to the bit.

  When the second drive shaft 50 rotates, the bevel gear 52 provided at the upper end of the second drive shaft 50 rotates, and the ring gear 53 engaged with the bevel gear 52 rotates. At this time, if the hammer mode is selected by rotating the mode switching dial 60, that is, as shown in FIG. 2, if the engagement between the ring gear 53 and the sleeve 54 is released, the rotation of the ring gear 53 is performed. Is not transmitted to the cylinder 10, and the ring gear 53 idles on the cylinder 10. Therefore, the rotational force is not transmitted to the bit, and only the striking force is transmitted.

  On the other hand, when the hammer drill mode is selected by rotating the mode switching dial 60, that is, as shown in FIG. 1, when the ring gear 53 and the sleeve 54 are engaged, the ring gear 53 is rotated. The cylinder 10 and the retainer sleeve 11 rotate integrally. Therefore, the impact force is intermittently transmitted to the bit held by the retainer sleeve 11 and the rotational force is continuously transmitted.

  Next, various circuits included in the hammer drill 1 according to the present embodiment, the circuit configuration of the brushless motor 30, and the like will be described with reference to FIG. As shown in FIGS. 1 and 2, a control board 100 is provided between the brushless motor 30 and the handle 5. As shown in FIG. 3, the brushless motor 30, the trigger switch 71, the rotation direction switching button 80, the lighting unit 81, the operation panel 90 and the like are electrically connected to the control board 100. In addition, a motor control unit 105 including a switching circuit 102, a rectifier circuit 103, a power factor correction circuit 104, a controller 106, and the like, which will be described later, is mounted on the control board 100.

  As shown in FIG. 3, the stator 31 of the brushless motor 30 (FIGS. 1 and 2) includes coils U1, V1, and W1 corresponding to the U phase, the V phase, and the W phase. On the other hand, the rotor 32 (FIGS. 1 and 2) of the brushless motor 30 is provided with four types of two permanent magnets having different polarities. These four permanent magnets are arranged at equal intervals along the rotation direction of the rotor 32. As shown in FIG. 3, in the vicinity of the rotor 32, three magnetic sensors S1, S2, S3 are arranged. These magnetic sensors S 1, S 2, S 3 detect a change in magnetic force accompanying the rotation of the rotor 32 and output an electrical signal to the rotor position detection circuit 101. Hall elements are used for the magnetic sensors S1, S2, and S3 in the present embodiment.

  The switching circuit 102 shown in FIG. 3 controls energization to the coils U1, V1, W1 of the stator 31. In front of the switching circuit 102, there are a rectifier circuit 103 that converts alternating current into direct current, and a power factor improvement circuit 104 that boosts the voltage of the direct current output from the rectifier circuit 103 and supplies the boosted voltage to the switching circuit 102. Has been placed. The rectifier circuit 103 is a bridge circuit in which four diode elements are connected to each other. The power factor correction circuit 104 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 the high-frequency current generated in the switching circuit 102. Suppress below the value.

  The switching circuit 102 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 VI and control the current supplied to the coil V1. The switching elements Tr5 and Tr6 are connected to the coil WI 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 correction circuit 104, and the switching elements Tr2, Tr4, Tr6 are connected to the negative output terminal of the power factor improvement circuit 104. 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 present 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 105 shown in FIG. 3 includes a controller 106 as a control unit, a control signal output circuit 107, a rotor position detection circuit 101, and a motor rotation speed detection circuit 108. The controller 106 calculates and outputs a signal for controlling the brushless motor 30. A control signal output from the controller 106 is input to the switching circuit 102 via the control signal output circuit 107. The rotor position detection circuit 101 detects the rotational position of the rotor 32 (FIGS. 1 and 2) 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 32. . A position detection signal output from the rotor position detection circuit 101 is input to the controller 106 and the motor rotation speed detection circuit 108. The motor rotation speed detection circuit 108 detects the rotation speed of the rotor 32, 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 108 is input to the controller 106. The controller 106 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 106 shown in FIG. 3 receives an ON signal and an OFF signal output from the trigger switch 71 in accordance with the operation of the trigger lever 70 shown in FIGS. When the trigger lever 70 shown in FIGS. 1 and 2 is operated by an operator, an on signal or an off signal is output from the trigger switch 71 according to the operation. Specifically, when the trigger lever 70 is pulled, an on signal is output from the trigger switch 71, and when the trigger lever 70 is released, an off signal is output from the trigger switch 71, or the output of the on signal is stopped. The When the controller 106 receives the ON signal output from the trigger switch 71, the controller 106 determines that the trigger switch 71 is turned ON. On the other hand, the controller 106 determines that the trigger switch 71 is turned off when the off signal output from the trigger switch 71 is received or the reception of the on signal is interrupted.

  The rotation direction switching signal output from the rotation direction switching button 80 shown in FIGS. 1 and 2 is input to the controller 106 shown in FIG. The rotation direction switching button 80 in the present embodiment is a tactile switch that outputs (transmits) a signal each time it is operated. Therefore, a rotation direction switching signal is input to the controller 106 shown in FIG. 3 every time the rotation direction switching button 80 is operated. In other words, the controller 106 receives a rotation direction switching signal every time the rotation direction switching button 80 is pressed.

Reference is again made to FIGS. The intermediate housing 3 is provided with a sensor 62 as a mode detection unit. The sensor 62 outputs (transmits) an electrical signal (mode detection signal) when the mode switching dial 60 is rotated to a predetermined position. The mode detection signal output from the sensor 62 is input to the controller 106 shown in FIG. The mode switching dial 60 shown in FIGS. 1 and 2 includes a permanent magnet 60a. When the mode switching dial 60 is rotated to the position shown in FIG. 2, that is, when the hammer mode is selected, the permanent magnet 60a built in the mode switching dial 60 is located near the sensor 62 (in this embodiment, Located just above the sensor 62). Then, the magnetic force of the permanent magnet 60a is detected by the sensor 62, and a mode detection signal is output from the sensor 62. On the other hand, when the mode switching dial 60 is rotated to the position shown in FIG. 1, that is, when the hammer drill mode is selected, the permanent magnet 60 a built in the mode switching dial 60 is separated from the sensor 62. Then, the magnetic force of the permanent magnet 60a is not detected by the sensor 62, and the output of the mode detection signal from the sensor 62 is interrupted. Therefore, the controller 106 shown in FIG. 3 can determine whether or not the selected operation mode is the hammer mode based on whether or not the mode detection signal is input.
(First control flow)
Next, an example of control (on / off control) of the brushless motor 30 executed by the controller 106 shown in FIG. 3 will be described with reference mainly to FIGS. In the following description, the brushless motor 30 is abbreviated as “motor 30”.

  When the power cable is connected to the power source, control by the controller 106 is started. First, the controller 106 sets the rotation direction of the motor 30 to the normal rotation (S1). Next, it is determined whether or not the rotation direction switching button 80 has been operated, that is, whether or not a switching signal has been received from the rotation direction switching button 80 (S2). If no switching signal is received from the rotation direction switching button 80, it is determined whether or not the trigger switch 71 is turned on (S3). That is, it is determined whether or not the trigger lever 70 (FIGS. 1 and 2) is pulled.

  When the trigger switch 71 is turned on (S3: Yes), the controller 106 turns on the motor 30 (S4).

  When the trigger switch 71 is not turned on (S3: No), the controller 106 repeats steps S2 and S3. During this time, when the rotation direction switching button 80 is operated and a switching signal is received (S2: Yes), the controller 106 Sets the rotation direction to reverse rotation (S4) and turns on the LED 81 (S5).

  When the trigger switch 71 is turned on (S3: Yes), the motor 30 is turned on (S6). When the rotation direction of the motor 30 is normal rotation (S7: Yes), the speed setting button on the operation panel 90 is used. The target rotational speed is set as shown in FIG. 8 according to the speed thus set, and the controller 106 performs constant speed control so that the rotor 32 rotates at the target rotational speed (S8). This speed control is continued until the trigger switch 71 is turned off (S9: Yes). When the trigger switch 71 is turned off (S9: No), the motor 30 is turned off (S10). Thereafter, it is determined again in step S2 whether or not the rotation direction switching button 80 is operated.

  When the trigger switch 71 is turned on (S3: Yes), the motor 30 is turned on (S6), and when the rotation direction of the motor 30 is reverse (S7: No), energization time counting is started (S11), and the speed The target rotational speed is set as shown in FIG. 8 according to the speed set by the setting button, and the controller 106 performs constant speed control so that the rotor 32 rotates at the target rotational speed (S12). If the trigger switch 71 is turned off (S14: No) before the work state in the reverse rotation continues for 10 seconds or longer (S13: No), the motor 30 is turned off (S15), and the energization time count is finished. Then, the LED 81 is turned off (S17), and the rotation direction is set to the normal rotation (S18). Thereafter, it is determined again in step S2 whether or not the rotation direction switching button 80 is operated.

  When it is determined that the work state in the reverse rotation has continued for 10 seconds or longer (S13: Yes), the LED 81 is blinked (S19). Thereafter, it is determined whether or not the work state in the reverse rotation has continued for 15 seconds or more (S20). If it is determined that the work state has continued for 15 seconds or more (S20: Yes), the motor 30 is turned off (S21), While the trigger switch 71 is kept on, the LED 81 is kept blinking. If it is determined in step S22 that the trigger switch 71 has been turned off, the process proceeds to step S16, the energization time is counted, the LED 81 is then turned off (S17), and the rotation direction is further set to normal rotation (S18).

The reciprocating tool shown in FIGS. 1 to 7 has the following characteristics and effects.
(1) When reverse rotation is set and during work in reverse rotation, the LED 81 is turned on so that the operator can recognize that it is in reverse rotation and that it is driven in reverse rotation. It is possible to prevent the work from being performed unnecessarily in the reverse rotation state.

In addition, it may replace with LED81 and may be another lighting means, and the structure which alert | reports to an operator by a sound, a vibration, etc. may be sufficient.
(2) Basically, in the reciprocating tool in which the operation of rotating the motor 30 in the forward direction is performed, the fan 35 can be designed on the basis of the forward rotation, so that the fan 35 can be downsized. In this configuration, when the fan 35 is rotated in the reverse direction, the cooling effect by the fan 35 is reduced. Therefore, in the reverse rotation state, the motor 30 can be driven at a high speed with a large amount of heat generated by limiting the number of rotations of the motor 30 to be smaller than that in the normal rotation to reduce the drive energy of the motor. There is no need to consider increasing the size of the fan 35 or improving the heat resistance of the tool itself.

In the above embodiment, the target rotational speed is limited. However, for example, in a control method for controlling the rotation of the motor 30 with a fixed duty, the duty is more limited in the reverse rotation state than in the normal rotation. There may be a configuration in which the conduction angle of the switching element is limited.
(3) When the gear tooth portion is inclined with respect to the shaft to increase the contact area between the tooth portions to improve the life of the gear, the gear and the shaft integral with the gear or the gear are received. An axial load is applied to the shaft, and in the case of a reciprocating tool that can rotate forward and reverse, it is necessary to design in consideration of the load in both directions. There is no need to increase the load resistance of the bearing that receives the shaft on both sides, increasing the degree of freedom in design.
(4) For the purpose of improving the efficiency of the motor 30, a mechanical advance structure may be employed. In the embodiment in which the brushless motor 30 is mounted, the advance angle control is possible by controlling the switching timing of the switching circuit. However, the positions of the rotor 32 and the magnetic sensors S1 to S3 can be controlled without controlling the timing. A mechanical advance structure can be obtained by slightly shifting. In a structure in which a motor with a brush is mounted, a mechanical advance structure can be obtained by slightly shifting the mounting angle of the brush. Such a mechanical advance structure is usually designed so that the efficiency of the motor 30 is improved by forward rotation, and the rotation efficiency is lowered by reverse rotation. In the present invention, in a reciprocating tool adopting such a mechanical advance structure, it is possible to limit continuous work in a reverse rotation state with low efficiency and work at high speed rotation with lower efficiency, It is possible to extend the service life.
(5) After the operation in the reverse rotation is completed, the reverse rotation operation can be prevented from being continuously performed by automatically setting the rotation direction to the normal rotation. In addition to this, it is possible to prevent the operator from misidentifying the rotation direction by adopting a configuration in which the lighting unit notifies that the vehicle is in the reverse rotation state and is driven in the reverse rotation.
(6) By operating the rotation direction switching button 80, the period during which the rotation direction is switched is set to the period when the trigger switch 71 is turned off, that is, only when the trigger lever 70 is not operated. It is possible to prevent the rotation direction switching button 80 from being operated unexpectedly and to prevent the rotation from being switched unexpectedly, thereby preventing problems such as troubles in work and a reduction in product life.
(7) When the reverse rotation work is performed continuously for a predetermined time or longer, the lighting part blinks and warns, so that the reverse rotation work state is continuously performed and problems such as product life are suppressed. it can.
(Second control flow)
Next, another example of the control (on / off control) of the brushless motor 30 executed by the controller 106 shown in FIG. 3 will be described with reference mainly to FIGS.

  When the power cable is connected to the power source, control by the controller 106 is started. The controller 106 determines whether or not the trigger lever 70 is pulled and the trigger switch 71 is turned on (S1). When the trigger switch 71 is turned on (S1: Yes), the controller 106 determines whether or not the rotation direction of the motor 30 is normal rotation (S2), and if it is normal rotation (S2: Yes), the motor 30 is turned on (S3), and the rotational speed control of forward rotation as shown in FIG. 8 is performed (S4). When the trigger switch 71 is on, S2 to S5 are repeated, and when the trigger switch 71 is turned off (S5: No), the motor 30 is turned off (S6).

  In Step 2, when it is determined that the rotation direction of the motor 30 is reverse rotation (S2: No), it is then determined whether or not the hammer mode is set (S7). When it is determined that the hammer drill mode is selected instead of the hammer mode (S7: No), the motor 30 is turned on (S8), the reverse rotation speed control as shown in FIG. 8 is performed, and the LED 81 is lit (S10). ). When the trigger switch 71 is on, steps S2 and S7 to S11 are repeated. When the trigger switch 71 is turned off (S11: No), the motor 30 is turned off (S12), and the LED 81 is turned off (S13).

  When it is determined in step S7 that the hammer mode is selected, the LED 81 is blinked without starting the motor 30 (S14). The blinking of the LED 81 continues until the trigger switch 71 is turned off (S15).

  The reciprocating tool equipped with the control method shown in FIG. 9 has the following characteristics and effects.

  In the hammer mode in which the tip tool only reciprocates, the operator cannot recognize the rotation direction of the motor 30 by looking at the tip tool, regardless of whether the motor 30 is driven forward or reversely. In the present embodiment, in such a hammer mode, even if the trigger switch 71 is turned on, the motor 30 is not driven, that is, the motor 30 is in a limit mode in which the energy for driving the motor 30 is zero. It is possible to prevent the reciprocating tool from operating in the reverse state, and to extend the life of the product. Further, by blinking the LED 81, it is possible to prompt the operator to switch the rotation direction by notifying the worker that the motor 30 is not driven by determining that the state is abnormal, not a product failure or the like.

  Note that the motor 30 may be limited to be driven at an ultra-low speed in the reverse rotation state in the hammer mode.

Further, the motor 30 may be a brush motor instead of the brushless motor 30 and may be provided with a changeover switch for changing over the energization circuit to the motor instead of the rotation direction changeover button 80. When the trigger lever 70 is operated, the electric power in the forward / reverse rotation direction is supplied to the motor 30 regardless of the control of the controller 106. In such a configuration, after the motor is actually driven, the direction of the current is confirmed and the rotation direction is determined in step S2, and the motor is turned off after it is determined that the motor is in the reverse rotation state and the hammer mode. Become. Note that the changeover switch for switching the energization circuit to the motor is configured to maintain the state of the forward rotation position and the reverse rotation position.
(Third control flow)
Next, a third embodiment, which is a modification of the second control flow, will be described with reference to FIG.

  The difference from the embodiment of FIG. 9 is the control when the trigger lever 70 is operated in the state where the hammer mode is selected and the reverse rotation is selected.

  In the present embodiment, when reverse rotation is selected and it is determined in step S7 that the hammer mode is selected (S7: Yes), the motor is driven in the normal rotation regardless of the selection state of the rotation direction (S3, S3). S4).

  By adopting such control, it is possible to provide a reciprocating tool with good workability that does not reliably reverse the motor 30 and does not require re-operation of the trigger lever 70 in the hammer mode.

  The present embodiment is a reciprocating tool equipped with the brushless motor 30 configured to drive the motor 30 by switching the switching of the switching element by the controller 106 as a control unit, and therefore can be easily realized. When the trigger lever 70 is operated, it is difficult to realize with a brushed motor that is configured to supply electric power in the forward / reverse rotation direction to the motor 30 regardless of the control of the controller 106.

  The present invention is not limited to the embodiment described above, and various modifications can be made without departing from the scope of the invention. For example, the present invention can be applied to a reciprocating tool in which the rotational motion of the motor is converted into the reciprocating motion of the piston by an eccentric cam or the like, and the rotational force of the motor is transmitted to the tip tool, and the tip tool performs the reciprocating motion. It can be applied to reciprocating tools such as hammers, jigsaws, saversaws and clippers. In particular, in a cutting tool such as a jigsaw, saver saw, clipper, etc., it is most suitable for a reciprocating tool provided with a function of reversely rotating for the purpose of releasing the state that the tip tool has been bitten during the forward rotation.

DESCRIPTION OF SYMBOLS 1 Hammer drill 2 Cylinder housing 3 Intermediate housing 4 Motor housing 5 Handle 10 Cylinder 20 Piston 30 Brushless motor (motor)
60 Mode switching dial 62 Sensor 70 Trigger lever 71 Main switch 80 Rotation direction switching button 81 LED

Claims (11)

A motor,
A tip tool that transmits the rotational force of the motor and can reciprocate to cut the counterpart material;
A control unit for controlling the driving of the motor;
A trigger operated by an operator to turn on and off the motor;
A reciprocating tool comprising rotation direction switching means operated by an operator to switch the rotation direction of the motor to forward rotation and reverse rotation,
The control unit controls the motor in a limit mode when the rotation direction of the motor is set to reverse rotation,
The controller is
In the limit mode, when the trigger is turned on, the motor is driven, and even when the trigger is turned on, the motor is stopped when a predetermined stop condition is satisfied,
In a state other than the restriction mode, the motor is driven when the trigger is turned on, and the motor is driven regardless of whether the predetermined stop condition is satisfied or not when the trigger is turned on. A reciprocating tool characterized by maintaining the drive of   2. The reciprocating tool according to claim 1, wherein, in the restriction mode, the energy for driving the motor is smaller than that in a case where the rotation direction of the motor is normal rotation.   3. The reciprocating tool according to claim 1, wherein the control unit reduces the set rotational speed of the motor in the restriction mode as compared with a case where the rotation direction of the motor is normal rotation. 4. .   The reciprocating tool according to any one of claims 1 to 3, wherein the predetermined stop condition is that a continuous drive time of the motor is a predetermined time or more.   The reciprocating tool according to any one of claims 1 to 4, wherein the tip tool can perform the same reciprocating motion regardless of the rotation direction of the motor. A fan that rotates by rotation of the motor and generates cooling air that cools the motor;
The reciprocating motion according to any one of claims 1 to 5, wherein the fan has a shape in which a cooling performance when the motor rotates forward is superior to a cooling performance when the motor rotates reversely. tool. The motor is a brushless motor, includes a switching element, and includes an inverter circuit that supplies power to the brushless motor by performing a switching operation of the switching element.
The reciprocating tool according to claim 1, wherein the control unit controls the switching operation. The controller is
The reciprocating tool according to any one of claims 1 to 7, wherein in the restriction mode, when the driving of the motor is stopped, the restriction mode is canceled regardless of an operation of the rotation direction switching means.   The reciprocating tool according to claim 1, wherein the rotation direction switching unit is a tactile switch that outputs a signal to the control unit each time the rotation direction switching unit is operated.   The reciprocating tool according to claim 1, further comprising a display unit that displays whether or not the control unit is in the restriction mode. A motor,
A tip tool that transmits the rotational force of the motor and can reciprocate to cut the counterpart material;
A control unit for controlling the driving of the motor;
A trigger operated by an operator to turn on and off the motor;
Rotation direction switching means operated by an operator to switch the rotation direction of the motor between forward rotation and reverse rotation;
A reciprocating tool comprising: a fan that rotates by rotation of the motor and generates cooling air that cools the motor ;
The tip tool can perform the same reciprocating operation regardless of the rotation direction of the motor,
The fan has a shape in which the cooling performance when the motor rotates in the forward direction is superior to the cooling performance when the motor rotates in the reverse direction,
The control unit controls the motor in a limit mode when the rotation direction of the motor is set to reverse rotation,
The control unit drives the motor by reverse rotation when the trigger is turned on in the limit mode, and stops driving the motor and cancels the limit mode when the trigger is turned off thereafter. Thus, when the trigger is turned on again, the reciprocating tool is configured to drive the motor in a normal rotation without operating the rotation direction switching means .