JP6519949B2 - Electric tools and combinations of electric tools and attachments - Google Patents

Description

  The present invention relates to a power tool that can mount an attachment.

  BACKGROUND Conventionally, a power tool such as a hammer drill capable of mounting an attachment for dust collection has been widely used. In this type of electric power tool, in addition to the fan for motor cooling, a fan for dust collection is attached to the rotary shaft of the motor in the tool main body, and the two fans coaxially rotate together as the motor rotates. Then, when air generated by the rotation of the dust collection fan passes from the tool main body to the attachment, dust and the like generated by the drilling operation are sucked into the attachment (see Patent Document 1 below).

JP, 2010-201525, A

  However, in the above-described conventional electric power tool, two fans are provided on the rotary shaft of the motor, and it is necessary to secure an air path communicating from the tool body side to the inside of the attachment. There is a problem that the configuration becomes complicated. In addition, when the number of revolutions of the motor is decreased due to an increase in load during operation, the number of revolutions of the dust collection fan is also reduced, so that the dust collection efficiency is reduced and the workability is impaired.

  In view of such a subject, an object of the present invention is to provide an electric tool which can miniaturize a tool body and can obtain good workability.

In order to solve the above problems, a first motor, a battery mounting portion to which a battery pack serving as a drive source of the first motor can be mounted, and an attachment mounting portion capable of mounting an attachment having a second motor An attachment mounted on the attachment mounting portion, the apparatus further comprising: supply means for supplying a drive voltage of a second motor; and control means for controlling the drive of the first motor and the second motor, The control means performs change control to change the battery voltage of the battery pack attached to the battery attachment unit to the drive voltage for the second motor when the battery voltage is higher than a predetermined voltage, and the drive is performed A voltage is supplied to the second motor, and when the battery voltage is less than the predetermined voltage, the battery voltage is supplied to the second motor without performing the change control. To provide an electric tool that.
In order to solve the above problems, the present invention can further mount an attachment having a first motor, a battery mounting portion to which a battery pack serving as a driving source of the first motor can be mounted, and a second motor. An attachment mounting unit, a supply unit that supplies a drive voltage of the second motor to the attachment mounted on the attachment mounting unit, and a control unit that controls driving of the first motor and the second motor, The control means changes the battery voltage of the battery pack mounted in the battery mounting portion into a drive voltage for the second motor, and supplies the drive voltage to the second motor .

  According to this configuration, since the first motor and the second motor are provided independently, the second motor can be driven regardless of the operating condition of the first motor. Therefore, even when the rotational speed of the first motor decreases due to the load, the second motor can be driven at the desired rotational speed, and the workability is improved. Further, since only the first motor is mounted on the power tool main body and the second motor is mounted on the attachment side, downsizing of the tool main body is realized. Furthermore, since the battery pack attached to the tool body serves as a drive source for the first motor and the second motor, attachment of the battery pack is unnecessary on the attachment side, and the attachment can be miniaturized. Further, since the drive voltage of the second motor is supplied by changing the battery voltage of the battery pack, it becomes possible to mount the motors having different drive voltages on the tool body and the attachment, respectively. Therefore, since the motor and the battery pack can be selected according to the work content, it is possible to further improve the workability. Furthermore, since the control means provided in the tool main body performs change control of the battery voltage, the control means becomes unnecessary on the attachment side, and the number of parts and the cost can be reduced.

In the power tool described above, the battery mounting portion can mount a plurality of battery packs having different rated voltages, and the control means identifies the battery pack mounted on the battery mounting portion, and the rated voltage of the battery pack was obtained as the battery voltage, it is preferable to vary the degree of transformer in the change control based on the acquired battery voltage.

  According to this configuration, since the power supply control to the second motor is changed according to the type of the attached battery pack, a plurality of battery packs can be used, and the convenience is improved.

The above-described power tool may further include voltage detection means for detecting the battery voltage of the battery pack mounted in the battery mounting portion. In this case, the control means preferably vary the extent of the transformer in the change control based on the detected battery voltage by the voltage detecting means.

  According to this configuration, since the power supply control to the second motor is changed according to the detected battery voltage, control according to the usage condition of the battery is possible. Therefore, further improvement of the operability is possible.

  Moreover, it is preferable that a battery mounting part can mount | wear with multiple types of battery pack from which a rated voltage differs.

  According to this configuration, it is possible to use a plurality of types of battery packs, and the convenience is improved.

  Preferably, the control means supplies the battery voltage to the second motor without performing change control when the battery voltage is equal to or lower than a predetermined voltage.

  According to this configuration, when the battery voltage is equal to or lower than the predetermined voltage, voltage change is not performed, so power consumption accompanying the voltage change can be suppressed, and a decrease in workability can be prevented.

  It is preferable that the above-described electric power tool further includes step-down means provided between the supply means and the battery pack and having a switching element for changing the battery voltage of the battery pack to the drive voltage by the control means.

  According to this configuration, the battery voltage is changed to an appropriate voltage value, and power can be supplied to the second motor.

  In the electric power tool described above, when the battery voltage is higher than the predetermined voltage, the control unit reduces the battery voltage to a predetermined voltage or less by the step-down unit, and supplies the stepped-down battery voltage to the second motor as the drive voltage. Is preferred.

  According to this configuration, when the battery voltage is higher than the predetermined voltage, the voltage is lowered to an appropriate voltage value and power is supplied to the second motor, so that occurrence of a defect such as breakage of the second motor can be prevented. Become.

  Preferably, the step-down means is a step-down circuit that steps down the battery voltage to a predetermined voltage or less.

  According to this configuration, the battery voltage can be stepped down to an appropriate voltage value by the step-down circuit, and power can be supplied to the second motor. Therefore, damage to the second motor due to application of high voltage can be prevented.

  Preferably, the control means performs change control of the battery voltage by changing the duty ratio of the PWM signal supplied to the switching element.

  According to this configuration, it is possible to lower the voltage average value by changing the duty ratio. Therefore, the battery voltage can be stepped down to an appropriate voltage value with a simple configuration, and power can be supplied to the second motor.

  The power tool described above may further include current detection means for detecting the current value of the second motor. In this case, preferably, the control means stops the supply of the drive voltage to the second motor when the current value exceeds the predetermined current value.

  According to this configuration, it is possible to prevent a large current from flowing to the second motor, so it is possible to suppress the breakage of the second motor and to prolong the life of the attachment.

  In the electric power tool described above, it is preferable that the control means start supply of the drive voltage to the second motor after a predetermined time has elapsed after the start of the drive of the first motor.

  According to this configuration, the drive of the second motor is started after the start of the drive of the first motor. Therefore, even when the start current is generated when the drive of each motor is started, the simultaneous occurrence of the start current is suppressed. Be done. Therefore, it is possible to suppress damage to the switching element and other parts, and to extend the life of the tool body.

  Preferably, the control means stops the supply of the drive voltage to the second motor after a predetermined time has elapsed after the drive stop of the first motor.

  According to this configuration, when the driving of the first motor is stopped, the driving of the second motor is also stopped, so it is possible to save power by suppressing the consumption of the battery.

  The above-described electric power tool may further include determination means for determining whether or not the attachment is attached to the attachment attachment portion. In this case, the control means preferably stops the supply of the drive voltage to the second motor when it is determined by the determination means that the attachment is not attached.

  According to this configuration, since the power feeding operation is performed only when the attachment is attached, the consumption of the battery can be suppressed. In addition, even when the attachment is removed while the first motor is driven to work with the tool main body, the step-down operation of the battery voltage can be stopped, so power saving can be achieved.

  In the electric power tool described above, the attachment is preferably a dust collection device having suction means, dust collection means and a fan.

  According to this configuration, the attachment is attached, and the second motor is driven by power supply from the tool body to rotate the fan on the attachment side, thereby sucking and collecting dust and the like generated in the work by the tool body. It becomes possible. In addition, as described above, when the supply of the drive voltage to the second motor is stopped after a predetermined time has elapsed after the drive of the first motor is stopped, the dust and the like generated by the work of the tool main body is assured It becomes possible to suction.

  In addition, the battery pack preferably includes a lithium ion battery.

  According to this configuration, even when using a lithium ion battery having a large fluctuation range of the battery voltage due to charge and discharge, the voltage can be changed to an appropriate voltage and power can be supplied to the second motor, so that good workability can be ensured. It becomes possible.

Further, the present invention is a combination of a power tool and an attachment, characterized by comprising the above-described power tool and an attachment having a second motor and attached to the attachment mounting portion of the power tool. provide.
Furthermore, in order to solve the above-mentioned problems, the present invention further provides an attachment having a first motor, a battery mounting portion to which a battery pack serving as a driving source of the first motor can be mounted, and a second motor. An attachment mounting portion that can be mounted, a supply unit that supplies a driving voltage of a second motor to an attachment that is mounted to the attachment mounting portion, and a control that controls driving of the first motor and the second motor And the control unit performs change control to change the battery voltage of the battery pack attached to the battery attachment unit to the drive voltage for the second motor, and the drive voltage is changed to the second drive voltage. And a determination unit configured to determine whether or not the attachment is attached to the attachment attachment unit, the control unit further comprising: If the mounting is discriminated that there is no, and provides a power tool characterized by stopping the supply of the driving voltage to the second motor.

  According to the combination of the power tool and the combination of the power tool and the attachment according to the present invention, it is possible to miniaturize the tool main body and to secure good workability.

It is a side view which shows the external appearance of the hammer drill and dust collection attachment which concern on embodiment of this invention. (A) shows a hammer drill, (b) shows a dust collection attachment. It is a sectional side view which shows the internal structure of the hammer drill and dust collection attachment which concern on embodiment of this invention. It is a circuit diagram which shows the electric constitution of the hammer drill and dust collection attachment which concern on 1st Embodiment. It is a flow chart which shows operation of a hammer drill concerning a 1st embodiment. It is explanatory drawing which shows the time change of the voltage supplied to a dust collection motor in case battery voltage is 42V. It is explanatory drawing which shows the time change of the voltage supplied to a dust collection motor in case battery voltage is 36V. It is explanatory drawing which shows the time change of the voltage supplied to a dust collection motor in case battery voltage is 24V. It is explanatory drawing which shows the time change of the voltage supplied to a dust collection motor in case battery voltage is 21V. It is explanatory drawing which shows the time change of the voltage supplied to a dust collection motor, when a battery voltage is 18 V or less. (A) shows the case where the battery voltage is 18 V, and (b) shows the case where the battery voltage is 15 V. It is a circuit diagram which shows the electric constitution of the hammer drill which concerns on 2nd Embodiment, and a dust collection attachment. It is a flow chart which shows operation of a hammer drill concerning a 2nd embodiment. It is a circuit diagram which shows the electric constitution of the hammer drill and dust collection attachment which concern on 3rd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. Here, the case where the present invention is applied to a cordless hammer drill to which a dust collection attachment can be attached will be described as an example. In addition, the same code | symbol is attached | subjected to the same or equivalent component shown by each drawing, a member, etc., and the overlapping description is abbreviate | omitted suitably. Further, each embodiment does not limit the invention, and is merely an example, and all the features described in each embodiment and the combination thereof are not necessarily essential.

  First, the configuration of the hammer drill and the dust collection attachment according to the embodiment of the present invention will be described based on FIG. 1 (a), FIG. 1 (b) and FIG. Fig.1 (a) and FIG.1 (b) are side views which show the external appearance of the hammer drill which concerns on embodiment of this invention, and a dust collection attachment, FIG. 1 (a) shows a hammer drill, FIG.1 (b) Indicates a dust collection attachment. FIG. 2 is a side sectional view showing an internal configuration of the hammer drill and the dust collection attachment according to the embodiment of the present invention. The hammer drill 100 is a tool capable of mounting the battery pack 200 and the dust collection attachment 300 and driving a tip tool (not shown) such as a drill blade to perform a drilling operation. FIG. 2 shows the hammer drill 100 with the battery pack 200 and the dust collecting attachment 300 attached. For the convenience of description, in the drawings, the front shown in the drawing is defined as the front, the back as the rear, the upper as the upper, and the lower as the lower, and the right is the right and the left is the left Define as

  The hammer drill 100, as shown in FIG. 2, includes a housing 1, a tool motor 2, a power transmission mechanism 4, and a tip tool attaching / detaching mechanism 5, and is used in a state where a tip tool not shown is attached to the tip tool attaching / detaching mechanism 5. Ru. The hammer drill 100 has, as operation modes, a rotary impact mode in which the tip tool rotates and strikes, a rotational mode in which only the rotation is performed, and an impact mode in which only the impact is performed.

  The housing 1 forms an outer shell of the hammer drill 100, and includes a motor housing 11, a gear housing 12, and a handle housing 15.

  The motor housing 11 is made of, for example, a resin, has a substantially cylindrical shape extending in the vertical direction, and accommodates the tool motor 2 therein. An intake port 11a for taking in the cooling air and an exhaust port 11b for discharging the taken-in cooling air are formed on the side surface of the motor housing 11, respectively. In addition, the motor housing 11 is provided with an attachment mounting surface 11 d for mounting the dust collection attachment 300 and a set of terminals 11 c for electrically connecting with the mounted dust collection attachment 300. The attachment mounting surface 11d corresponds to the attachment mounting portion of the present invention, and the terminal 11c corresponds to the supply means of the present invention.

  The gear housing 12 is made of, for example, a resin, has a cylindrical shape, and is open at the front and the rear. The gear housing 12 is connected to the top of the motor housing 11 and to the front of the handle housing 15. In the embodiment, the handle housing 15 and the motor housing 11 are formed by an integral resin member, and are divided into two in the left-right direction having mating surfaces in the front-rear direction, and the motor 2 and the control board 3 are accommodated therein. Do. The gear housing 12 accommodates the power transmission mechanism 4 therein.

  Inside the gear housing 12, as shown in FIG. 2, a cylinder case 13 is disposed. The cylinder case 13 is made of steel and has a substantially cylindrical shape, and is disposed inside the gear housing 12 so that the axial direction of the cylinder coincides with the front-rear direction. At the front of the cylinder case 13, a tip tool attaching / detaching mechanism 5 for attaching / detaching a tip tool (not shown) is provided.

  The handle housing 15 has a handle 14 as shown in FIGS. 1 and 2. The handle 14 is a portion gripped by a user when using the hammer drill 100, has a substantially U-shape in side view, and is disposed to the rear of the motor housing 11 and the gear housing 12. Further, as shown in FIGS. 1A and 2, the handle 14 is provided with a trigger 14 a for controlling the driving of the tool motor 2.

  The trigger 14 a is electrically connected to the control board 3 inside the handle housing 15. When the user pulls the trigger 14 a backward, a signal for starting the tool motor 2 is output to the control board 3. Further, the number of rotations of the tool motor 2 can be changed by the amount of pulling in the trigger 14a.

  A battery pack mounting surface 14 b is formed on the lower portion of the handle 14 of the handle housing 15. A battery pack 200 containing a plurality of battery cells such as lithium ion batteries is detachably mounted on the battery pack mounting surface 14b. The battery pack mounting surface 14b corresponds to the battery mounting portion of the present invention.

  The tool motor 2 is a drive source for driving the tip tool attached to the tip tool attaching / detaching mechanism 5. The tool motor 2 has a rotating shaft 21 extending upward as shown in FIG. 2 and is accommodated in the motor housing 11, and the rotating shaft 21 is located in a gear case 16 made of steel, The axial direction of the rotating shaft 21 is arranged to coincide with the vertical direction, and is rotatably supported. A pinion gear 21 a is integrally formed with the rotation shaft 21 at the upper end of the rotation shaft 21. The pinion gear 21 a transmits the rotation of the tool motor 2 to the power transmission mechanism 4. Further, a fan 22 for motor cooling is mounted on the proximal end of the rotary shaft 21 so as to be coaxially and integrally rotated. Further, below the tool motor 2, a sensor substrate 6 on which an inverter circuit or the like described later is mounted is disposed.

  The control board 3 is a circuit board disposed in front of the handle 14 inside the handle housing 15, and is connected to the trigger 14a, the sensor board 6, and the like. A control circuit, a step-down switching element, and the like, which will be described later, are mounted on the control board 3.

  The power transmission mechanism 4 includes a bevel gear 40, an intermediate shaft 41, a sleeve 42, a clutch mechanism 43, a transmission gear 44, a motion conversion unit 45, a cylinder 46, a piston 47, a striker 48, and an intermediate 49 And consists of.

  As shown in FIG. 2, the intermediate shaft 41 is disposed in the gear case 16 and the gear housing 12 so as to correspond to the front-rear direction so as to be substantially orthogonal to the rotation shaft 21 of the tool motor 2 and rotatably supported. ing. A bevel gear 40 is disposed at the rear end of the intermediate shaft 41 and meshes with the pinion gear 21 a of the rotating shaft 21. The bevel gear 40 rotates with the intermediate shaft 41 as the pinion gear 21 a rotates.

  A sleeve 42 is provided at the front of the intermediate shaft 41. Further, between the sleeve 42 and the bevel gear 40, the clutch mechanism 43 and the movement converting unit 45 are disposed from the front.

  The sleeve 42 is integrally rotatable with the intermediate shaft 41 and is in mesh with the transmission gear 44. The rotational force of the intermediate shaft 41 is transmitted to the sleeve 42 via the clutch mechanism 43. The transmission gear 44 meshes with the sleeve 42 and is fixed to the cylinder 46 to transmit the rotation of the sleeve 42 to the cylinder 46.

  The clutch mechanism 43 switches between a rotary impact mode in which the rotation of the intermediate shaft 41 is transmitted to the sleeve 42 and the motion conversion unit 45, a rotational mode in which transmission is performed only to the sleeve 42, and an impact mode transmitted only to the motion conversion unit 45. There is. The operation mode of the hammer drill 100 is switched based on the operation of the clutch mechanism 43.

  The movement converting unit 45 includes a rotating unit 45a, a ball 45b, and an arm unit 45c.

  The rotating portion 45a is integrally rotatable with the intermediate shaft 41, and a groove 45d recessed inward is formed. The ball 45b is engaged with a receiving portion 45e formed in the groove 45d and the arm 45c. When the rotating portion 45a rotates, the ball 45b moves along the groove 45d. As a result, the upper end of the arm 45c reciprocates in the front-rear direction, and the rotational movement of the rotating unit 45a is converted to the reciprocating movement of the tip of the arm 45c.

  An upper end portion of an arm 45 c is connected to the piston 47, and reciprocates in the front-rear direction in the cylinder 46 in conjunction with the reciprocation of the arm 45 c. The cylinder 46 accommodates the piston 47 and the intermediate 49. The striker 48 has a substantially cylindrical shape, and is provided in the piston 47 so as to be slidable in the front-rear direction. In the piston 47, an air chamber 47a is defined by the rear end surface of the striker 48 and the inner peripheral surface of the piston 47. The intermediate 49 is substantially cylindrical and located in front of the striker 48.

  The tip tool attaching / detaching mechanism 5 is provided on the front side of the gear housing 12 and includes a tool holding portion 50 which detachably holds the tip end tool.

  As shown in FIG. 2, the dust collection attachment 300 includes a housing 51, a dust collection motor 52, a slider part 53 and an adapter part 54, and is used by being attached to the hammer drill 100. The dust collection attachment 300 has a function of suctioning dust generated by the tip tool of the hammer drill 100.

  The housing 51 is made of, for example, a resin, and includes a motor housing 55 and a dust collection housing 56.

  The motor housing 55 is substantially L-shaped in a side view, and accommodates the dust collection motor 52 inside. An exhaust port 55 a is formed on the side surface of the motor housing 55. Further, an attachment portion 55 b for attaching the dust collection attachment 300 to the attachment attachment surface 11 d formed on the motor housing 11 of the hammer drill 100 is formed on the top of the motor housing 55. A mounting button 55c is provided on the mounting portion 55b. The user attaches and detaches the dust collection attachment 300 to the hammer drill 100 while pressing the attachment button 55c.

  The dust collection housing 56 has a substantially cylindrical shape extending in the vertical direction, and is detachably attached to the front of the motor housing 55 and below the slider portion 53. The dust collection housing 56 accommodates the dust collection case 57 inside. The dust collection case 57 is, for example, a paper filter, is detachably attached to the dust collection housing 56, and accommodates the sucked dust.

  The dust collection motor 52 is a motor with a brush, is accommodated in the motor housing 55, and is disposed such that the rotation shaft 52a coincides with the front-rear direction. A dust collection fan 58 is mounted on the proximal end of the rotary shaft 52a of the dust collection motor 52 so as to be coaxially and integrally rotated. Further, the dust collection motor 52 is connected to a pair of lead wires 52 b for supplying a drive voltage. The terminal 52 c of the lead wire 52 b can be pulled out from a hole (not shown) formed in the mounting portion 55 b of the motor housing 55.

  The slider portion 53 is made of, for example, a resin, and includes a slider case 53a and an adapter mounting portion 53b. The slider case 53 a has a substantially cylindrical shape extending in the front-rear direction, and is disposed above the dust collection housing 56. The adapter mounting portion 53b can be accommodated in the inside of the slider case 53a and can be drawn forward, and the adapter portion 54 is mounted at the front end. In FIG. 2, the adapter mounting portion 53 b is pulled forward and disposed at the most extended position. The adapter mounting portion 53b is pulled out when the dust collection attachment 300 is used, and is accommodated inside the slider case 53a when not used.

  The adapter portion 54 is made of, for example, a resin, is attached to the front end portion of the slider portion 53, and has a shape extending upward. The upper end portion of the adapter portion 54 has an annular shape in a front view, and the tip tool of the hammer drill 100 can pass through the inside of the annular portion of the upper end portion of the adapter portion 54 in the front and rear direction when attaching the dust collection attachment 300 to the hammer drill 100. It has become. Further, a suction port (not shown) is formed in the adapter portion 54.

  Next, attachment of the dust collection attachment 300 to the hammer drill 100 will be described. The dust collection attachment 300 is attached to and detached from the hammer drill 100 in the vertical direction. While pressing the mounting button 55 c of the dust collection attachment 300, the user slides the mounting portion 55 b upward on the attachment mounting surface 11 d of the hammer drill 100 to mount the dust collection attachment 300 on the hammer drill 100. When the pressing of the mounting button 55 c is released, the mounting portion 55 b is locked to the attachment mounting surface 11 d of the hammer drill 100. In addition, one set of terminals 52 c drawn from the dust collection attachment 300 is inserted into and connected to the terminals 11 c of the hammer drill 100. Thus, the dust collection attachment 300 is electrically connected to the hammer drill 100.

  When the dust collection attachment 300 is mounted on the hammer drill 100, the upper end of the adapter portion 54 of the dust collection attachment 300 is disposed in the forward direction of the tip tool attaching / detaching mechanism 5 of the hammer drill 100, as shown in FIG. When the end tool is mounted on the tool holding unit 50, the end of the end tool passes the top of the adapter 54 and protrudes forward. In this state, the hammer drill 100 drives the tip tool to perform a drilling operation and the like.

  When removing the dust collection attachment 300 from the hammer drill 100, the user removes the terminal 52c of the dust collection attachment 300 from the terminal 11c of the hammer drill 100. Then, the user slides the mounting portion 55 b downward on the attachment mounting surface 11 d of the hammer drill 100 while pressing the mounting button 55 c. As a result, the engagement of the mounting portion 55 b with the attachment mounting surface 11 d is released, and the dust collection attachment 300 is removed from the hammer drill 100.

  Next, an outline of the operation of the hammer drill 100 will be described.

  When the user grips the handle 14 and pulls the trigger 14a while pressing the tip tool held in the tool holding unit 50 against the material to be drilled (not shown), the power of the battery pack 200 is supplied to the tool motor 2 and the tool motor The rotation shaft 21 of 2 rotates. The rotational force of the rotating shaft 21 is transmitted to the intermediate shaft 41 via the pinion gear 21 a and the bevel gear 40.

  In the rotational impact mode, when the intermediate shaft 41 rotates, the rotational force is transmitted to the cylinder 46 via the sleeve 42, and the cylinder 46 and the tip tool attaching / detaching mechanism 5 rotate. At the same time, as the intermediate shaft 41 rotates, the arm 45c of the motion converter 45 reciprocates in the front-rear direction.

  When the arm 45c starts to reciprocate and the piston 47 connected to the arm 45c moves backward, the air in the air chamber 47a expands and the pressure decreases. At this time, since the pressure of the space defined between the striker 48 and the intermediate 49 is higher than the pressure of the air chamber 47a, the striker 48 moves rearward.

  The piston 47 moves forward by reciprocating motion, and the air of the air chamber 47a is compressed by moving the striker 48 backward. The striker 48 is accelerated forward by the expansion of the compressed air of the air chamber 47a. The intermediate member 49 is struck by the striker 48, and an impact force is applied to the tip tool through the intermediate member 49. Then, the piston 47 moves back again by the reciprocating motion, and the striker 48 moves back.

  As described above, when the arm portion 45 c reciprocates, the piston 47 reciprocates, and the air repeats compression and expansion in the air chamber 47 a. Thereby, the striker 48 reciprocates in the front-rear direction, and the striking force is transmitted to the tip tool via the intermediate element 49. In the rotary striking mode, the tip tool rotates and strikes to process the material to be drilled.

  In the rotation mode, the rotary shaft 21 of the tool motor 2 is rotated by pulling the trigger 14 a, and the rotational force of the rotary shaft 21 is transmitted to the intermediate shaft 41 via the pinion gear 21 a and the bevel gear 40.

  As the intermediate shaft 41 rotates, the rotational force is transmitted to the cylinder 46 via the sleeve 42 and the transmission gear 44, and the tip tool rotates. At this time, since the clutch mechanism 43 does not transmit the rotation of the intermediate shaft 41 to the motion conversion unit 45, the arm unit 45c does not reciprocate. Thereby, only rotational force is transmitted to the tip tool.

  In the striking mode, the rotary shaft 21 of the tool motor 2 is rotated by pulling the trigger 14 a, and the rotational force of the rotary shaft 21 is transmitted only to the motion converter 45 through the clutch mechanism 43. The rotational force of the rotating shaft 21 is converted to reciprocating motion by the motion converter 45 and transmitted to the cylinder 46.

  As the cylinder 46 reciprocates, only the striking force is transmitted to the tip tool via the striker 48 and the intermediate element 49.

  Next, an outline of the operation of the dust collection attachment 300 will be described.

  With the dust collection attachment 300 mounted on the hammer drill 100, when the dust collection motor 52 is driven, the fan 58 rotates with the rotation shaft 52a. Thus, air containing dust and the like is sucked from the suction port formed in the adapter unit 54. The air flow descends the inside of the adapter portion 54, passes through the inside of the slider portion 53 in the backward direction, descends, and is guided to the inside of the dust collection case 57 in the dust collection housing 56. Then, air, dust and the like are separated by the dust collection case 57, the dust remains in the dust collection case 57, only air is guided in the backward direction, and the air is exhausted from the exhaust port 55a of the motor housing 55.

  Subsequently, the electrical configuration of the hammer drill 100 and the dust collection attachment 300 will be described in detail. FIG. 3 is a circuit diagram showing an electrical configuration of the hammer drill 100 and the dust collection attachment 300 according to the first embodiment. Hammer drill 100 is electrically connected to battery pack 200 and dust collecting attachment 300, as shown in FIG.

  On the battery pack mounting surface 14b of the hammer drill 100, plural types of battery packs having different rated voltages such as 14.4V, 18V, 25.2V, 36V, etc. can be mounted. In the example shown in FIG. 3, the battery pack 200 mounted on the hammer drill 100 includes the battery set 201, the battery protection IC 202, the plus terminal 203, the signal terminal 204, and the minus terminal 205, and the battery pack It is assumed that 200 has a rated voltage of 36V.

  The battery set 201 includes, for example, a plurality of lithium ion battery cells. The negative terminal of the battery cell with the lowest potential in the battery set 201 is connected to the negative terminal 205, and the positive terminal of the battery cell with the highest potential is connected to the positive terminal 203.

  The lithium-ion battery has a rated voltage of 3.6 V per cell, and a large output can be obtained, while the fluctuation range of the battery voltage is large, and the hammer drill 100 with a large output continues drilling for a long time. If done, it is known that the battery voltage drops significantly.

  The battery protection IC 202 is a circuit that monitors the voltage of each battery cell of the battery set 201, and is connected to the signal terminal 204. The battery protection IC 202 outputs a motor stop signal via the signal terminal 204 when, for example, any of the battery cells constituting the battery set 201 is in an overdischarged state lower than a predetermined voltage.

  The hammer drill 100 is comprised including the plus terminal 101, the signal terminal 102, the minus terminal 103, the terminal 11c, the tool motor 2, the inverter circuit 7, the trigger 14a, and the control part 8, as FIG. 3 shows.

  The plus terminal 101, the signal terminal 102, and the minus terminal 103 are provided on the battery pack mounting surface 14b, respectively. The battery pack 200 is electrically connected to the hammer drill 100 by connecting the plus terminal 203, the signal terminal 204, and the minus terminal 205 to the plus terminal 101, the signal terminal 102, and the minus terminal 103 of the hammer drill 100, respectively.

  The terminal 11 c is a set of terminals for voltage supply, and is provided on the motor housing 11 as shown in FIG. One terminal 52 c of the dust collection attachment 300 is connected to the terminal 11 c.

  The tool motor 2 is a three-phase brushless motor in the present embodiment, and its rated voltage is 36V. The tool motor 2 is configured to include a rotor having a rotating shaft 21 (FIG. 2) and a plurality of magnets, and a stator formed of three-phase coils, and the coil of the tool motor 2 is connected to the inverter circuit 7 Ru. The tool motor 2 corresponds to the first motor of the present invention.

  The inverter circuit 7 is configured to include six switching elements Q1 to Q6 connected in a three-phase bridge type. Here, the switching elements Q1 to Q6 are, for example, MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) or IGBTs (Insulated Gate Bipolar Transistors), and are mounted on the sensor substrate 6 (FIG. 2). Each gate of the six switching elements Q1 to Q6 is connected to the control unit 8, and each drain or each source is connected to a coil. The inverter circuit 7 supplies drive power to the coil of the tool motor 2 by performing a switching operation.

  The trigger 14 a is disposed between the control unit 8 and the inverter circuit 7. When the trigger 14a is pulled by the user, the controller 8 starts the supply of the drive signal to the inverter circuit 7 based on the signal from the trigger 14a. Thereby, the switching operation of the inverter circuit 7 and the supply of the drive power to the tool motor 2 are started.

  The control unit 8 is mounted on the control substrate 3 in the gear housing 12 and, in the present embodiment, is configured to include a control circuit 81 and a step-down switching element 82.

  In the present embodiment, control circuit 81 includes a microcomputer and a power generation circuit for generating a power supply for the microcomputer, and is activated by the input of the battery voltage from battery pack 200. The control circuit 81 controls the energization direction and energization time to the coil so as to control the rotation direction, the rotation speed, and the like of the tool motor 2 in accordance with the operation of the trigger 14a. The control circuit 81 is connected to the gates of the six switching elements Q1 to Q6 of the inverter circuit 7 and supplies drive signals for turning on and off the switching elements Q1 to Q6. The control circuit 81 is connected to the signal terminal 102, and when the motor stop signal is input from the battery pack 200, the control circuit 81 stops the supply of the drive signal to the switching elements Q1 to Q6 and stops the tool motor 2. The control circuit 81 corresponds to the control means of the present invention.

Furthermore, the control circuit 81 includes a detection to the voltage detecting circuit (not shown) of the battery voltage V _B of the battery set 201 of the battery pack 200, in accordance with the detected battery voltage V _B, the dust collecting attachment 300 Control the supply of drive voltage. Further, control circuit 81 includes a current detection circuit (not shown) for detecting motor current I _A flowing to dust collection motor 52 of dust collection attachment 300, and motor current I _A exceeds predetermined current threshold I _TH . If it does, the drive of the dust collection motor 52 is stopped. The control circuit 81 corresponds to the voltage detection means and the current detection means of the present invention.

  The step-down switching element 82 is, for example, a MOSFET or an IGBT, and is disposed between the negative terminal 103 connected to the battery pack 200 and the terminal 11 c connected to the dust collection attachment 300. The gate of the step-down switching element 82 is connected to the control circuit 81, and is turned on / off by a drive signal from the control circuit 81.

The control circuit 81 supplies a pulse width modulation signal (PWM signal) as a drive signal to the gate of the step-down switching element 82 in the present embodiment. The control circuit 81, by changing the pulse width of the PWM signal, steps down the battery voltage V _B to the desired voltage. Hereinafter, the pulse width of the PWM signal is represented by the duty ratio D (%). That is, the control circuit 81 supplies the PWM signal of the duty ratio D to the gate of the step-down switching element 82.

  As shown in FIG. 3, the dust collection attachment 300 includes a set of terminals 52 c and a dust collection motor 52.

  The terminal 52 c is inserted into and connected to a voltage supply terminal 11 c provided in the hammer drill 100. The drive voltage of the dust collection motor 52 is input to the dust collection attachment 300 from the hammer drill 100 via the terminal 52c.

  The dust collection motor 52 is a brushed motor in the present embodiment, and is driven based on a drive voltage input via the terminal 52c to rotate the fan 58 (FIG. 2). Here, unlike the tool motor 2 mounted on the hammer drill 100, the dust collection motor 52 mounted on the dust collection attachment 300 is used only for the rotation of the fan 58, so a large output is unnecessary. Therefore, the dust collection motor 52 is smaller than the tool motor 2, and in the present embodiment, a motor with a rated voltage of 18 V is employed. The dust collection motor 52 corresponds to a second motor of the present invention.

  By the way, although multiple types of battery packs can be mounted on the battery pack mounting surface 14b of the hammer drill 100 as described above, since the rated voltage of the tool motor 2 of the hammer drill 100 is 36 V, the rated voltage is normally rated. The battery pack 200 of 36V is attached. The hammer drill 100 can obtain a sufficient output by setting the battery voltage of the battery pack 200 as the drive voltage of the tool motor 2. On the other hand, since the rated voltage of the dust collection motor 52 of the dust collection attachment 300 is 18 V, when the battery voltage of the battery pack with a rated voltage of 36 V is directly supplied as the drive voltage of the dust collection motor 52 It may be damaged. In order to prevent damage to the dust collection motor 52, for example, the battery pack is separately attached to the dust collection attachment 300, or the driving voltage supplied from the hammer drill 100 side into the dust collection attachment 300 is reduced. It is conceivable to provide a step-down circuit for the purpose and a control circuit for controlling the step-down circuit, but both lead to an increase in the number of parts, resulting in problems such as an increase in size of the dust collecting attachment 300 and an increase in cost.

  Therefore, in the present embodiment, the step-down switching element 82 is provided in the hammer drill 100 to reduce the battery voltage and supply it to the dust collection attachment 300 to prevent the dust collection motor 52 from being damaged. Further, by enabling both the inverter circuit 7 and the step-down switching element 82 to be controlled by one control circuit 81, an increase in the number of parts is suppressed, and downsizing of the hammer drill 100 and the dust collection attachment 300 is achieved.

  FIG. 4 is a flowchart showing the operation of the hammer drill 100 according to the first embodiment. The operation of the hammer drill 100 according to the present embodiment will be described in detail along the flowchart.

  When the user grips the handle 14 and pulls the trigger 14a, a signal is sent from the trigger 14a to the control circuit 81. With this signal as a trigger, the flowchart of FIG. 4 is started. The control circuit 81 supplies a drive signal to the inverter circuit 7 to start driving the tool motor 2 (step S101). Thus, driving of the tip tool is started.

  After starting the driving of the tool motor 2, the control circuit 81 stands by for a predetermined time (step S102). In the present embodiment, the predetermined time is 0.2 seconds. Here, the control circuit 81 stands by for a predetermined time after the start of driving of the tool motor 2 in order to prevent the start current of the tool motor 2 and the start current of the dust collection motor 52 from being generated simultaneously.

After 0.2 seconds has elapsed, the control circuit 81 detects the battery voltage _{V B} of the battery pack 200 mounted in the battery pack mounting surface 14b (step S103), whether or not higher than 18V battery voltage _{V B} Is determined (step S104). Here, 18 V means the rated voltage of the dust collection motor 52 mounted on the dust collection attachment 300.

If higher than 18V battery voltage _{V B} (step S104: YES), the control circuit 81, the duty ratio D of the PWM signal supplied to the step-down switching element 82, equation _{D = 18 / V B × 100} (%) Calculated and set based on (step S105). Also, if the battery voltage _{V B} is 18V or less (step S104: NO), the control circuit 81 is set to D = 100 (%) (step S106).

Then, the control circuit 81 supplies the PWM signal of the set duty ratio D to the step-down switching element 82 (step S107). Thus, the step-down switching element 82 is turned on, via a terminal 11c, the dust-collecting motor 52 of the dust collecting attachment 300, the driving voltage V _A is supplied. The dust collection motor 52 rotates with the fan 58 based on the supply of the drive voltage V _A , and the dust collection attachment 300 starts dust collection by the wind of the fan 58.

When supply of drive voltage V _A to dust collection attachment 300 is started, control circuit 81 detects motor current I _A flowing to dust collection motor 52, and determines whether or not current threshold I _TH is reached (step S108). When the motor current I _A is less than the current threshold I _TH (step S108: NO), there is no input of the motor stop signal from the battery pack 200 (step S109: NO), and the trigger 14a is turned on (step S110: YES), the control circuit 81 again detects the battery voltage _{V B} (step S103). Then, based on the battery voltage _{V B} that is newly detected, to set the duty ratio D, and supplies the PWM signal of the set duty ratio D, and the step-down switching element 82 (step S104 to S107).

When the trigger is turned off (step S110: NO), the control circuit 81 stops the supply of the drive signal to the inverter circuit 7 and stops the driving of the tool motor 2 (step S111). Similarly, also when the motor current I _A reaches the current threshold I _TH (step S108: YES) or when a motor stop signal is input from the battery pack 200 via the signal terminal 102 (step S109: YES), The control circuit 81 stops the driving of the tool motor 2 (step S111).

  After stopping the driving of the tool motor 2, the control circuit 81 stands by for a predetermined time (step S112). In the present embodiment, the predetermined time is 2 seconds. While the control circuit 81 is on standby, the drive of the tool motor 2 is stopped, but the drive of the dust collection motor 52 is continued, and the dust collection attachment 300 continues the dust collection operation.

After 2 seconds, the control circuit 81 stops the supply of the PWM signal to the step-down switching element 82 (step S113). Thereby, the supply of the drive voltage _VA to the dust collection attachment 300 is stopped, and the driving of the dust collection motor 52 is stopped.

As described above, based on the detected battery voltage V _B, the duty ratio D of the PWM signal supplied to the voltage-falling switching element 82 is set.

Here, the relationship between the battery voltage V _B , the duty ratio D, and the drive voltage V _A supplied to the dust collection motor 52 will be described with reference to FIGS. 5 to 9. FIGS. 5-8, respectively, showing the time variation of the voltage of the battery voltage _{V B} is supplied 42V, 36V, the dust collecting motor 52 in the case of 24V and 21V. Further, FIG. 9 shows the time variation of the voltage of the battery voltage V _B is supplied to the dust collecting motor 52 in the case of 18V or less.

The battery pack 200 of a lithium ion battery having the rated voltage of 36V, at full charge, are known to be capable of outputting a 42V battery voltage V _B. When detecting the battery voltage V _B = 42 V, the control circuit 81 sets D = 43% as the duty ratio D of the PWM signal. At this time, the temporal change of the voltage supplied to the dust collection motor 52 via the terminal 11c has a waveform as shown in FIG. That is, the waveform of the voltage supplied to the dust collection motor 52 is a rectangular wave having a maximum voltage of 42 V and alternately having an on period of 43% and an off period of 57%. At this time, the time average value of the voltage supplied to the dust collection motor 52 is 18V. That is, the dust collection motor 52 is supplied with the drive voltage V _A = 18 V, which is the same value as the rated voltage.

Continuing the drive of the hammer drill 100 by mounting the battery pack 200, the battery voltage V _B decreases gradually. For example, when the control circuit 81 detects a battery voltage V _B = 36 V lower than that at full charge, the control circuit 81 sets a duty ratio D = 50% higher than at full charge. At this time, as shown in FIG. 6, the waveform of the voltage supplied to the dust collection motor 52 via the terminal 11c is a rectangle in which the maximum voltage is 36 V, and the on period 50% and the off period 50% alternately appear. It is a wave. The time average value of this voltage is 18 V, and the dust collection motor 52 is supplied with the drive voltage V _A = 18 V.

Further, when the control circuit 81 detects the battery voltage V _B = 24 V, a higher duty ratio D = 75% is set. At this time, as shown in FIG. 7, the voltage waveform supplied to the dust collection motor 52 is a rectangular wave in which the maximum voltage is 24 V and the on period 75% and the off period 25% appear alternately. The time average value of this voltage also becomes 18 V, and the dust collection motor 52 is supplied with the drive voltage V _A = 18 V.

Similarly, when the control circuit 81 detects the battery voltage V _B = 21 V, a higher duty ratio D = 86% is set. At this time, the voltage waveform supplied to the dust collection motor 52 is a rectangular wave having a maximum voltage of 21 V and an on period of 86% and an off period of 14% alternately appearing, as shown in FIG. The value is 18V. The dust collection motor 52 is supplied with the drive voltage V _A = 18V.

Further lowering the battery voltage _{V B,} the control circuit 81 detects the battery voltage _V B = 18V, setting the duty ratio D = 100%. At this time, as shown in FIG. 9A, the dust collection motor 52 is supplied with a drive voltage _VA of a constant value 18V.

When the battery voltage _{V B} falls to 18V or less, the control circuit 81 sets the duty ratio D = 100%. In this case, the dust collecting motor 52, a constant voltage equal to the battery voltage V _B is supplied as the drive voltage V _A. For example, in the case of the battery voltage V _B = 15 V, as shown in FIG. 9B, the dust collection motor 52 is supplied with a drive voltage V _A of a constant value 15 V.

  As described above, in the hammer drill 100 according to the present embodiment, the dust collection motor 52 is also provided on the dust collection attachment 300 side independently of the tool motor 2 on the hammer drill 100 side. Regardless, the dust collecting motor 52 can be driven. Therefore, even when the rotational speed of the tool motor 2 is reduced due to the load, the dust collection motor 52 can be stably driven to rotate, and good workability can be obtained.

  Further, only the tool motor 2 and the fan 22 for cooling the tool motor 2 are mounted on the main body of the hammer drill 100, and the dust collection fan 58 is mounted on the dust collection attachment 300 side together with the dust collection motor 52. While being able to miniaturize the hammer drill 100 main body, it becomes unnecessary to secure a complicated air path.

  Further, since the battery pack 200 mounted on the hammer drill 100 also serves as a driving source for the dust collecting motor 52 as well as the tool motor 2, mounting of the battery pack on the dust collecting attachment 300 is unnecessary. Miniaturization is also possible. Further, even when the drive voltage of the dust collection motor 52 is lower than the battery voltage of the battery pack 200, the battery voltage can be lowered to supply an appropriate drive voltage to the dust collection motor 52. While being able to select a motor and a battery pack, it becomes possible to prevent the occurrence of a defect such as breakage of the dust collection motor 52 due to the application of a high voltage. Therefore, the convenience and the workability can be improved, and the life of the dust collection attachment 300 can be extended. Furthermore, even if a control circuit is not provided on the dust collection attachment 300 side, power supply control to both the tool motor 2 and the dust collection motor 52 is performed by the control circuit 81 on the hammer drill 100 side, thereby reducing the number of parts and cost. Is possible.

  In the hammer drill 100 of the present embodiment, the battery voltage is lowered by changing the duty ratio D of the PWM signal supplied to the step-down switching element 82. Therefore, the battery voltage can be reduced with a simple configuration, the enlargement of the main body of the hammer drill 100 is suppressed, and complicated control becomes unnecessary. Furthermore, since the duty ratio D is changed according to the battery voltage detected during driving of the tool motor 2, an appropriate drive voltage is supplied to the dust collection motor 52 even when the battery voltage fluctuates with the work. . Therefore, it is possible to suppress the decrease in workability due to the decrease in battery voltage.

  In addition, since driving of the dust collection motor 52 is started after a predetermined time has elapsed after the start of driving of the tool motor 2, it is possible to suppress breakage of parts due to simultaneous occurrence of the start current. Therefore, the life extension of the hammer drill 100 is possible. Furthermore, after the drive of the tool motor 2 is stopped, the drive of the dust collection motor 52 is automatically stopped after a lapse of a predetermined time, so that the consumption of the battery can be suppressed and power saving can be achieved. After completion of the drilling operation by 100, the dust collection operation by the dust collection attachment 300 is continued for a predetermined time, so that the generated dust and the like can be reliably suctioned.

  Furthermore, when the motor stop signal is input from battery pack 200 or when the motor current flowing through dust collection motor 52 reaches a predetermined current threshold, driving of hammer drill 100 and dust collection attachment 300 is stopped, so the battery The life of the pack 200 and the dust collecting attachment 300 can be extended.

  Next, a hammer drill 400 and a dust collection attachment 500 according to a second embodiment will be described. The hammer drill 400 according to the second embodiment is characterized in that the discrimination resistance 409 for discriminating the attachment of the dust collection attachment 500 is provided, and the configuration in which the step-down circuit 482 is provided in the control unit 408 is the first embodiment. It is different from In addition, the same code | symbol is attached | subjected to the component equivalent to 1st Embodiment, or equivalent, a member, etc., and the overlapping description is abbreviate | omitted suitably.

  FIG. 10 is a circuit diagram showing an electrical configuration of the hammer drill 400 and the dust collection attachment 500 according to the second embodiment. The hammer drill 400 according to the second embodiment, as shown in FIG. 10, includes a tool motor 2, an inverter circuit 7, a trigger 14a, a control unit 408, a terminal 11c, a terminal 401, and a discrimination resistance 409. .

  The control unit 408 is mounted on the control board 3 (FIG. 2), and is configured to include a control circuit 481 and a step-down circuit 482 in the present embodiment.

In the present embodiment, control circuit 481 is configured to include a microcomputer and a power generation circuit, and is activated by the input of the battery voltage from battery pack 200, and according to the operation of trigger 14a, the direction of current flow and current flow to the coil. In order to control time, a drive signal is supplied to the inverter circuit 7. Further, the control circuit 481, a voltage detection circuit that detects a battery voltage V _B of the battery pack 200 includes a (not shown), in accordance with the detected battery voltage V _B, the drive voltage to the dust collecting attachment 500 Perform supply control. Further, control circuit 81 includes a current detection circuit (not shown) for detecting motor current I _A flowing to dust collection motor 52 of dust collection attachment 300, and motor current I _A exceeds predetermined current threshold I _TH . If it does, the drive of the dust collection motor 52 is stopped. The control circuit 81 corresponds to control means, voltage detection means and current detection means of the present invention.

The step-down circuit 482 is a step-down chopper circuit and includes a switching element 483, a choke coil 484, a diode 485 and a capacitor 486 as shown in FIG. Step-down circuit 482, and outputs the stepping down the battery voltage V _B which is input through the switching element 483. The output from the step-down circuit 482 is supplied to the dust collection attachment 300 via a set of terminals 11c. In other words, the step-down circuit 482 steps down the battery voltage _{V B,} and outputs a driving voltage _{V A} of the dust collection motor 52.

  In the step-down circuit 482, the switching element 483 is, for example, a MOSFET or an IGBT, and its gate is connected to the control circuit 481. The switching element 483 is turned on / off by the PWM signal from the control circuit 481.

When the step-down rate of the voltage by the step-down circuit 482 is expressed as ΔV = V _A / V _B × 100 (%), this step-down rate ΔV is equal to the duty ratio D of the PWM signal supplied to the switching element 483. That is, ΔV = D. Therefore, as in the first embodiment, control circuit 481 sets duty ratio D = 18 / V _B × 100 (%) when battery voltage V _B is higher than 18 V, and battery voltage V _B Is set to D = 100 (%) when the voltage is 18 V or less.

  The terminal 401 is a terminal for connection with the dust collection attachment 300. In the present embodiment, the hammer drill 400 is connected to the dust collection attachment 500 via the three terminals 11c, 11c, and 401 including one set of the terminals 11c. The terminal 401 corresponds to the attachment mounting portion of the present invention.

  Discrimination resistor 409 is connected to terminal 401. The control circuit 481 detects attachment of the dust collection attachment 500 to the terminal 401 and the terminal 11c by detecting the current flowing through the determination resistor 409. The determination resistor 409 and the control circuit 481 correspond to the determination means of the present invention.

  As shown in FIG. 10, the dust collection attachment 500 is configured to include a pair of terminals 52c, a terminal 501, and a dust collection motor 52.

  The terminal 501 is a terminal for connecting to the terminal 401 of the hammer drill 400. The dust collection attachment 500 is electrically connected to the hammer drill 400 via a set of terminals 52 c and three terminals of the terminals 501.

  Next, the operation of the hammer drill 400 according to the present embodiment will be described. FIG. 11 is a flowchart showing the operation of the hammer drill 400 according to the second embodiment.

  In response to the input of a signal from the trigger 14a to the control circuit 481, the flowchart of FIG. 11 is started. The control circuit 481 supplies a drive signal to the inverter circuit 7 to start driving of the tool motor 2 (step S101). After starting the driving of the tool motor 2, the control circuit 481 stands by for a predetermined time (step S102). In the present embodiment, the predetermined time is 0.2 seconds.

  After 0.2 seconds have elapsed, the control circuit 481 determines whether the dust collection attachment 500 is attached (step S201). When the control circuit 481 detects the current flowing through the determination resistance 409, it determines that the dust collection attachment 500 is attached (step S201: YES).

If the dust collecting attachment 500 is mounted (step S201: YES), the control circuit 481 detects the battery voltage _{V B} of the battery pack 200 mounted in the battery pack mounting surface 14b (step S103), the battery voltage V _It is determined whether _B is higher than 18 V (step S104).

If higher than 18V battery voltage _{V B} (step S104: YES), the control circuit 481, the duty ratio D of the PWM signal supplied to the switching element 483 of the step-down circuit 482, equation _{D = 18 / V B × 100} ( Calculated and set (step S105). Also, if the battery voltage _{V B} is 18V or less (step S104: NO), the control circuit 481 sets the D = 100 (%) (step S106).

Then, the control circuit 481 supplies the PWM signal of the set duty ratio D to the switching element 483 of the step-down circuit 482 (step S202). Thus, the switching element 483 is turned on, the step-down circuit 482 steps down the battery voltage _{V B} in buck ratio [Delta] V = D, via the terminal 11c, the driving dust collecting motor 52 of the dust collecting attachment 500 voltage _V A = V _B × D / 100 is supplied. The dust collection motor 52 starts to rotate with the fan 58, and the dust collection attachment 500 starts dust collection.

With the dust collection attachment 500 mounted (step S203: YES), the control circuit 481 detects the motor current I _A flowing to the dust collection motor 52 during supply of the drive voltage to the dust collection attachment 500, and the current threshold It is determined whether or not I _TH has been reached (step S108). When the motor current I _A is less than the current threshold I _TH (step S108: NO), there is no input of the motor stop signal from the battery pack 200 (step S109: NO), and the trigger 14a is turned on (step S110: YES), the control circuit 81 again detects the battery voltage _{V B} (step S103). Then, based on the battery voltage _{V B} that is newly detected, to set the duty ratio D, and the PWM signal of the set duty ratio D, supplied to the switching element 483 of the step-down circuit 482 (step S104 to S106, S202) .

  When the trigger is turned off (step S110: NO), or when the motor stop signal is input from the battery pack 200 via the signal terminal 102 (step S109: YES), the control circuit 481 drives the inverter circuit 7. The supply of the signal is stopped to stop the driving of the tool motor 2 (step S111). After stopping the driving of the tool motor 2, the control circuit 481 waits for a predetermined time (step S112), and then stops the supply of the PWM signal to the switching element 483 of the step-down circuit 482 (step S204). In the present embodiment, the predetermined time is 2 seconds. As a result, the drive of the dust collection motor 52 is continued for 2 seconds from the drive stop of the tool motor 2, and then the drive of the dust collection attachment 500 is stopped.

During the supply of the PWM signal to the step-down circuit 482, if the dust collecting attachment 500 is detached (step S203: NO), or when the motor current _{I A} reaches the current threshold _{I TH} (step S108: YES), control The circuit 481 stops the supply of the PWM signal to the step-down circuit 482 while the driving of the tool motor 2 is continued (step S205).

  When there is no input of the motor stop signal from the battery pack 200 (step S206: NO) and the trigger 14a is turned on (step S207: YES), the control circuit 481 continues the driving of the tool motor 2. When the trigger is turned off (step S110: NO), or when the motor stop signal is input from the battery pack 200 (step S109: YES), the control circuit 481 supplies the drive signal to the inverter circuit 7. It stops and the drive of the tool motor 2 is stopped (step S208).

As described above, the battery voltage V _B is stepped down by the step-down circuit 482, the driving voltage V _A is supplied to the dust collecting motor 52.

  As described above, in the hammer drill 400 of the present embodiment, the step-down circuit 482 is provided, and the battery voltage of the battery pack 200 is actually stepped down and supplied to the dust collection attachment 300 side. The voltage can be reliably prevented from being applied to the dust collection motor 52. Therefore, damage to the dust collection motor 52 can be prevented, and the life of the dust collection attachment 300 can be extended.

  Further, a discrimination resistance 409 is provided for discriminating whether or not the dust collection attachment 300 is attached, and the step-down operation of the battery voltage is performed by the step-down circuit 482 only when the dust collection attachment 300 is attached. When the dust collection attachment 300 is removed during the driving of 2, the step-down operation of the battery voltage is stopped, so that the battery consumption can be suppressed.

  Furthermore, when the motor current flowing to the dust collection motor 52 reaches a predetermined current threshold value, only the driving of the dust collection motor 52 is stopped while the driving of the tool motor 2 continues, so that the dust collection motor 52 is damaged. While preventing, it becomes possible to suppress a decrease in work efficiency.

  In the present embodiment, only the tool motor 2 is driven when the dust collection attachment 300 is not mounted, but when the dust collection attachment 300 is mounted while the tool motor 2 is driven, the battery voltage is reduced. The operation and supply operation of the drive voltage to the dust collection motor 52 may be started.

  Next, a hammer drill 600 according to the third embodiment will be described. The hammer drill 600 according to the third embodiment is a modification of the hammer drill 100 according to the first embodiment, and differs from the first embodiment in that a brushed motor is mounted as a tool motor. In addition, the same code | symbol is attached | subjected to the component equivalent to 1st Embodiment, or equivalent, a member, etc., and the overlapping description is abbreviate | omitted suitably.

  FIG. 12 is a circuit diagram showing an electrical configuration of the hammer drill 600 and the dust collection attachment 300 according to the third embodiment. The hammer drill 600 which concerns on 3rd Embodiment is comprised including the tool motor 602, the switching element 607, the trigger 14a, and the control part 608, as FIG. 12 shows.

  The tool motor 602 is a brushed motor in the present embodiment. The tool motor 602 corresponds to the first motor of the present invention.

  The switching element 607 is, for example, a MOSFET or an IGBT, and is disposed between the negative terminal 103 connected to the battery pack 200 and the tool motor 602.

  The control unit 608 includes a control circuit 681 and a step-down switching element 82.

  In the present embodiment, control circuit 681 is configured to include a microcomputer and a power generation circuit, is activated by the input of the battery voltage from battery pack 200, and controls the drive of tool motor 602 in accordance with the operation of trigger 14a. Do. The control circuit 681 is connected to the gate of the switching element 607, and controls the driving of the tool motor 602 by supplying a driving signal to the switching element 607.

Further, as shown in FIG. 12, the control circuit 681 is connected to the gate of the step-down switching element 82. Control circuit 681, in order to step down the battery voltage _{V B,} a PWM signal having a duty ratio D, supplied to the gate of the voltage-falling switching element 82. Here, the duty ratio D is calculated as in the first embodiment.

With this configuration, the hammer drill 600 according to the third embodiment, like the first embodiment, steps down the battery voltage V _B, supplies the driving voltage V _A to the dust collecting motor 52 It becomes possible.

  As mentioned above, although demonstrated based on embodiment of this invention, this invention is not limited to the above-mentioned embodiment, A various change is possible within the range which does not deviate from the meaning.

  For example, in the above-described embodiment, the hammer drill repeatedly detects the battery voltage of the battery pack while driving the tool motor to calculate the step-down rate and the duty ratio of the PWM signal. It is not limited to. It is also possible to change the power supply control to the dust collection motor or to detect the battery voltage only when the driving of the tool motor is started by identifying the type of the battery pack mounted. As a result, the duty ratio is fixed, and power supply control to the dust collection motor becomes possible.

2, 602 tool motor 8, 408, 608 control unit 11c terminal 11d attachment mounting surface 14a trigger 14b battery pack mounting surface 52 dust collection motor 81, 481, 681 control circuit 82 step-down switching element 100, 400, 600 hammer drill 200 battery pack 300, 500 Dust collection attachment 409 Discrimination resistance 482 Step-down circuit

Claims (15)

The first motor,
A battery mounting portion capable of mounting a battery pack serving as a driving source of the first motor;
An attachment mounting portion capable of mounting an attachment having a second motor;
Supply means for supplying a drive voltage of a second motor to the attachment attached to the attachment attachment portion;
Control means for controlling driving of the first motor and the second motor;
When the battery voltage is higher than a predetermined voltage , the control unit performs change control to change the battery voltage of the battery pack attached to the battery attachment unit to the drive voltage for the second motor, The electric motor is characterized in that a driving voltage is supplied to the second motor, and the battery voltage is supplied to the second motor without performing the change control when the battery voltage is less than the predetermined voltage. tool. The battery mounting unit can mount a plurality of battery packs having different rated voltages,
Said control means, said identifying the battery pack attached to the battery holder, it obtains the rated voltage of the battery pack as the battery voltage, different degree of transformation in the change control based on the acquired battery voltage the power tool of claim 1, wherein the causing. It further comprises voltage detection means for detecting the battery voltage of the battery pack attached to the battery attachment part,
Wherein, power tool according to claim 1, wherein varying the degree of transformer in the change control based on the battery voltage detected by said voltage detecting means.   The power tool according to claim 3, wherein the battery mounting portion is capable of mounting a plurality of types of battery packs having different rated voltages. Electric tool according to any one of claims 1 to 4, further comprising a step-down means having a switching element for changing the battery voltage of the battery pack to the driving voltage by the pre-SL control means. When the battery voltage is higher than the predetermined voltage, the control unit steps down the battery voltage to the predetermined voltage or less by the step-down unit, and uses the battery voltage stepped down as the drive voltage. The electric power tool according to claim 5, characterized in that it is supplied to. The electric power tool according to claim 6, wherein the step-down means is a step-down circuit which steps down the battery voltage to the predetermined voltage or less. The motor control according to any one of claims 5 to 7 , wherein the control means performs change control of the battery voltage by changing a duty ratio of a PWM signal supplied to the switching element. tool. It further comprises current detection means for detecting the current value of the second motor,
The motor according to any one of claims 1 to 8 , wherein the control means stops the supply of the drive voltage to the second motor when the current value exceeds a predetermined current value. tool. 10. The control method according to any one of claims 1 to 9 , wherein the supply of the drive voltage to the second motor is started after a predetermined time has elapsed after the start of the drive of the first motor. The electric power tool according to item 1. 11. The control method according to any one of claims 1 to 10 , wherein the supply of the drive voltage to the second motor is stopped after a predetermined time has elapsed after the drive of the first motor is stopped. The electric power tool according to item 1. The first motor,
A battery mounting portion capable of mounting a battery pack serving as a driving source of the first motor;
An attachment mounting portion capable of mounting an attachment having a second motor;
Supply means for supplying a drive voltage of a second motor to the attachment attached to the attachment attachment portion;
Control means for controlling driving of the first motor and the second motor;
The control means performs change control to change the battery voltage of the battery pack attached to the battery attachment unit to the drive voltage for the second motor, and supplies the drive voltage to the second motor.
The apparatus further comprises determination means for determining the presence or absence of attachment of the attachment to the attachment attachment portion,
Wherein, when said mounting of the attachment is determined to not by discriminating means, the second feature and to that electrostatic dynamic tool to stop the supply of the drive voltage to the motor. The electric power tool according to any one of claims 1 to 12 , wherein the attachment is a dust collection device having suction means, dust collection means, and a fan. The power tool according to any one of claims 1 to 13 , wherein the battery pack comprises a lithium ion battery. An electric motor comprising: the electric power tool according to any one of claims 1 to 14 ; and an attachment having a second motor and attached to the attachment attachment portion of the electric power tool. Tool and attachment combination.

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