JP2013166209A - Impact tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an impact tool which effectively dissipates heat generated inside the impact tool.SOLUTION: An impact tool includes a brushless motor 20 which drives a tool bit 200, an electrical member 160 which controls drive of the brushless motor 20, and a cooling fan 90 which is driven to rotate by the brushless motor 20. The brushless motor 20 has a stator 22, a rotor 23, and a rotating shaft 21 to which the rotor 23 is attached. The brushless motor 20 is configured into an outer-rotor type motor having the rotor 23 located outside the stator 22. The brushless motor 20 and the electrical member 160 are cooled by cooling air generated by the cooling fan 90.

Description

  The present invention relates to an impact tool for performing a machining operation on a workpiece by at least linear movement of a tool bit.

  Japanese Patent Application Laid-Open No. 2008-302443 discloses a striking tool in which an electric motor linearly drives a tool bit attached to the tip of a striking tool to perform a machining operation on a workpiece. The impact tool described in the publication includes a control means for driving an electric motor that drives a tool bit. This control means is composed of a semiconductor such as a microprocessor, and the control means itself generates heat when the impact tool is used. Therefore, there is a possibility that the control means is destroyed by the heat generated and the impact tool cannot be controlled, and it is necessary to take measures to dissipate the heat generated in the impact tool.

JP 2008-302443 A

  The present invention has been made in view of the above, and an object thereof is to provide an impact tool that is effective in efficiently radiating the heat generated inside the impact tool.

  In order to solve the above problems, according to a preferred embodiment of the present invention, an impact tool for performing a predetermined processing operation on a workpiece by an impact operation in the major axis direction of a tool bit is configured. The striking tool includes a brushless motor that drives a tool bit, an electrical member that controls the driving of the brushless motor, and a cooling fan that is rotationally driven by the brushless motor. The brushless motor is configured as an outer rotor type having a stator, a rotor, and a rotation shaft to which the rotor is attached, and the rotor being disposed outside the stator. The brushless motor and the electrical member are cooled by cooling air generated by a cooling fan. Note that the “electrical member” in the present invention typically includes a drive current supply device for supplying a drive current to the brushless motor and a controller for controlling the drive current supply device.

  According to the present invention, since the motor and the electrical member that generate heat are cooled by the cooling air generated by the cooling fan, the heat generated in the brushless motor and the electrical member can be efficiently radiated. Further, according to the present invention, the brushless motor is an outer rotor type in which the rotor is disposed outside the stator, so that a larger torque can be generated as compared with the inner rotor type motor having the same outer dimensions. Thereby, compared with the conventional impact tool which requires a speed-reduction mechanism between the brushless motor and the drive shaft driven by the motor, it is possible to reduce the size and weight of the machine body and improve the operability.

  In the configuration in which the brushless motor and the electrical component are cooled by the cooling air generated by the cooling fan, in a further form of the impact tool according to the present invention, the electrical component is cooled by the cooling air downstream from the cooling fan. Is done. Moreover, in the further form of the impact tool which concerns on this invention, an electrical equipment member and a brushless motor are both cooled with the cooling air upstream of the fan which flows in into a cooling fan. By cooling in this way, in any of the above forms, the heat generated in the brushless motor and the electrical member can be efficiently dissipated.

  In a further aspect of the impact tool according to the present invention, the cooling air upstream of the fan is divided into a first cooling air guided to the brushless motor and a second cooling air guided to the electrical member, and the brushless motor and The electric component members are cooled by the independent cooling air flow. By cooling in this way, the heat generated in the brushless motor and the electrical member by the cooling air whose temperature is not high can be radiated efficiently and individually.

  In the further form of the impact tool which concerns on this invention, it is set as the structure by which the electrical equipment member is arrange | positioned in the upstream of cooling air rather than the brushless motor. In an impact tool using a motor, it is necessary to generate a large driving force by driving the motor with a large current when processing a workpiece. In particular, in an impact tool using a brushless motor, a large current flows through an electrical member that controls the brushless motor, and the electrical member tends to generate more heat than the brushless motor. Moreover, in order to efficiently dissipate the generated heat in a narrow housing, it is necessary to efficiently cool the electrical component that generates a large amount of heat. Therefore, by disposing the electrical component with a large amount of heat generation upstream of the cooling air from the brushless motor, the heat generated in the electrical component with a large amount of heat generated by the cooling air that is not high in temperature can be efficiently dissipated. Can do.

  According to the further form of the impact tool which concerns on this invention, while having a drive shaft arrange | positioned in parallel with the long axis of a tool bit and rotated by a brushless motor, the rotation output of the said drive shaft is transmitted and a tool bit is transmitted. It has a tool drive unit that drives linearly, and the rotation shaft and the drive shaft of the brushless motor are arranged coaxially. An electrical member is arranged on the long axis side of the tool bit with respect to the rotating shaft of the brushless motor. When the electrical component is thus arranged, the brushless motor and the electrical component are arranged in parallel with respect to the long axis direction of the tool bit. For this reason, it becomes possible to shorten the tool bit major axis direction dimension of the impact tool. Moreover, when it is set as the structure which arrange | positions the rotating shaft and drive shaft of a brushless motor coaxially, an empty area | region is formed in the long-axis line side of a tool bit. According to this aspect, since the electrical component can be arranged using this empty area, the outer shape in the direction intersecting the tool bit major axis direction of the impact tool can be reduced in size.

  According to the further form of the impact tool according to the present invention, the rotating shaft and the drive shaft of the brushless motor are arranged in parallel, and the electrical component is related to the long axis direction of the tool bit, Located on the opposite side. By adopting such an arrangement, the brushless motor and the electrical member are arranged in series with respect to the long axis direction of the tool bit, so the outer shape in the direction intersecting the long axis direction of the tool bit of the impact tool can be reduced. Can be planned.

  According to the further form of the impact tool which concerns on this invention, the cooling fan is arrange | positioned on the rotating shaft of a motor. Thus, by providing a cooling fan on a rotating shaft, the drive device for driving a cooling fan becomes unnecessary, and size reduction of an impact tool can be achieved.

  According to the further form of the impact tool which concerns on this invention, an electrical component is a drive current supply apparatus for supplying a drive current to a brushless motor, a controller which controls a drive current supply apparatus, a drive current supply apparatus, and a controller And a heat radiating member having a heat radiating surface having a predetermined area. At least the heat radiating surface of the heat radiating member is exposed to the air flow generated by the cooling fan. Thus, by exposing at least the heat radiating surface of the heat radiating member to the air flow generated by the cooling fan among the constituent members of the electric member, the heat generated in the electric member can be efficiently radiated.

  According to the present invention, a striking tool effective in efficiently dissipating heat generated inside the striking tool is provided.

It is a side view showing appearance of a hammer drill concerning a 1st embodiment of the present invention. 1 is a side sectional view showing an overall configuration of a hammer drill according to a first embodiment of the present invention. It is sectional drawing of the electrically equipped member for motor control which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the drive control system of the hammer drill which concerns on the 1st Embodiment of this invention. It is a side view which shows the external appearance of the hammer drill which concerns on the 2nd Embodiment of this invention. It is a sectional side view which shows the whole structure of the hammer drill which concerns on the 2nd Embodiment of this invention. It is a sectional side view which shows the whole structure of the hammer drill which concerns on the 3rd Embodiment of this invention.

(First embodiment of the present invention)
Hereinafter, the first embodiment of the present invention will be described in detail with reference to FIGS. In this embodiment, as an example of a striking tool, a hammer bit is struck in the long axis direction and rotated around the long axis direction, and a hammer drill is used to process the workpiece with the hammer bit. As shown in FIGS. 1 and 2, the hammer drill 100 holds a main body 110 as a tool main body that forms the outer shape of the hammer drill 100, a hand grip 120 and a side grip 140 that are gripped by an operator, and a hammer bit 200. The tool holder 150 is mainly configured. In the following, the right side of FIG. 1 is the front side of the hammer drill 100, the left side is the rear side of the hammer drill 100, the left-right direction of FIG. 1 is the front-rear direction of the hammer drill 100, and the vertical direction of FIG. The direction orthogonal to the paper surface will be described as the left-right direction of the hammer drill 100. The hammer bit 200 corresponds to the “tool bit” of the present invention.

  The main body 110 is constituted by the housing 10 on the outside. The housing 10 is formed by joining together a pair of substantially symmetrical housings, and houses the motor 20, the motion conversion mechanism 30, the power transmission mechanism 40, and the striking element 50 inside.

  The handgrip 120 extends rearward on the rear side of the hammer drill 100 and intersects the major axis of the hammer bit 200. The hand grip 120 is provided with a trigger 121. When the user operates the trigger 121, the motor 20 is energized and driven.

  The side grip 140 is detachably provided on the front side of the hammer drill 100. The side grip 140 includes an attachment ring portion 141 that is attached by gripping the outer peripheral surface of the housing 10 of the main body portion 110 from the outside, and a bolt 142 for tightening or loosening the attachment ring portion 141 with respect to the housing 10. Have. 1 and 2, the long axis direction of the side grip 140 coincides with the vertical direction of the hammer drill 100. However, by rotating the attachment ring portion 141 with respect to the housing 10, the side grip 140 can be moved in any direction. It can be attached to.

  The tool holder 150 is provided on the front surface of the main body 110. The tool holder 150 holds the hammer bit 200 so as to be detachable and relatively movable in the long axis direction, and transmits the rotation output of the motor 20 to the hammer bit 200.

  As shown in FIG. 2, the motor 20 is disposed in the housing 10 so that the rotating shaft 21 extends in the front-rear direction of the hammer drill 100. In the present embodiment, an outer rotor type DC brushless motor is used as the motor 20. A motion conversion mechanism 30, a power transmission mechanism 40, and a striking element 50 are disposed in front of the rotation shaft 21 of the motor 20. The motion conversion mechanism 30 and the striking element 50 correspond to the “driving unit that drives the tool bit linearly” according to the present invention.

  The motion conversion mechanism 30 is disposed in front of the rotation shaft 21 of the motor 20 and is a mechanism for converting the rotation output of the rotation shaft 21 into the output in the front-rear direction of the hammer drill 100. That is, the motion conversion mechanism 30 includes an intermediate shaft 32 that is rotationally driven by the rotary shaft 21, a rotary body 33 attached to the intermediate shaft 32, and a longitudinal direction of the hammer drill 100 as the intermediate shaft 32 (rotary body 33) rotates. The main component is a swinging member 34 that is swung to the right, a cylindrical piston 35 that reciprocates in the front-rear direction of the hammer drill 100 as the swinging member 34 swings, and a cylinder 36 that houses the piston 35. ing. The rotary shaft 21 and the intermediate shaft 32 are coaxially disposed and connected, and are disposed parallel to the long axis of the hammer bit 200 at a predetermined interval in a direction intersecting the long axis. . The cylinder 36 is integrally formed with the tool holder 150 as a rear region of the tool holder 150.

  The power transmission mechanism 40 is disposed on the front side of the motion conversion mechanism 30 and is a mechanism for transmitting the rotation output of the motor 20 transmitted from the intermediate shaft 32 of the motion conversion mechanism 30 to the tool holder 150. That is, the power transmission mechanism 40 is engaged with and engaged with the first gear 41 rotating with the intermediate shaft 32 and the second gear 42 attached to the tool holder 150 (cylinder 36). It is mainly composed of a gear reduction mechanism composed of these gears.

  The striking element 50 is disposed above the motion conversion mechanism 30 and behind the tool holder 150, and is linear in the longitudinal direction of the hammer drill 100 converted from the rotation output of the motor 20 by the motion conversion mechanism 30. This is a mechanism for transmitting the output to the hammer bit 200 as an impact force. That is, the striking element 50 is mainly configured by a striker 51 as a striking element slidably disposed in the cylindrical piston 35 and an impact bolt 52 disposed in front of the striker 51 and colliding with the striker 51. ing. Note that the space of the piston 35 behind the striker 51 forms an air chamber 53 that transmits the sliding motion of the piston 35 to the striker 51 via air pressure fluctuation.

  As shown in FIG. 2, the motor 20 which is a direct current brushless motor has a rotating shaft 21 and a substantially cylindrical bottomed rotation which is concentrically attached to the rotating shaft 21 and whose one end (front end) in the axial direction is closed. The main body is composed of a child 23 and a stator 22 which is disposed inside the rotor 23 and has a flange portion 22 a fixed to the housing 10. Stator coils 22U, 22V, and 22W (refer to FIG. 4) each having a three-phase winding are wound around the stator 22. A permanent magnet 23a extending in the axial direction of the rotating shaft 21 is embedded in the inner peripheral surface of the rotor 23, and the rotating shaft 21 is fixed through the center of the bottom. That is, the motor 20 employs an outer rotor type in which the rotor 23 is disposed outside the stator 22.

  The hammer drill 100 includes an electrical member 160 that controls driving of the motor 20. As shown in FIG. 3, the electrical member 160 includes a drive current supply device 70 that supplies a drive current from a power supply 130 (see FIG. 4) taken in via a power cord, and a controller 60 that controls the drive current supply device 70. And a storage container 80 that houses the drive current supply device 70 and the controller 60, and further includes a heat radiating plate 72 for radiating the heat generated by the drive current supply device 70 and the controller 60. As shown in FIG. 2, the electrical member 160 is disposed adjacent to the motor 20 at a position above the motor 20. That is, the motor 20 and the electrical member 160 are arranged in parallel in the long axis direction of the hammer bit 200.

  The motor 20 is disposed below the long axis of the hammer bit 200 so that the rotary shaft 21 is directly connected coaxially to the intermediate shaft 32 of the motion conversion mechanism 30. As a result, an empty area is formed above the motor 20 in the housing 10, and the electrical member 160 is disposed in this empty area. The upper part of the motor 20 corresponds to the “longer axis side of the tool bit than the brushless motor” in the present invention.

  Next, the electrical component 160 will be described in detail with reference to FIG. The storage container 80 is a rectangular parallelepiped box-shaped member that opens downward, and stores the controller 60 and the drive current supply device 70 therein. The storage container 80 corresponds to the “housing” of the present invention.

  The controller 60 calculates the position of the rotor 23 based on a printed circuit board, a central processing unit (CPU) disposed on the printed circuit board, and a signal from a position detection element 24 described later. ROM (Read Only Memory) storing various programs and data for controlling the drive current supply device 70, and RAM (Random Access Memory) temporarily storing data processed by the CPU Is the main constituent. In FIG. 3, only the printed circuit board of the controller 60 is shown, and the CPU, ROM, and RAM are not shown.

  The drive current supply device 70 is mainly composed of six switching elements 71, and a heat radiating plate 72 is connected to the upper surface of the switching elements 71 via a heat transfer material 73 such as silicon grease. Therefore, in the present embodiment, the heat radiating plate 72 is a member constituting the electrical member 160 and at the same time a member constituting the drive current supply device 70. As the switching element 71, an FET (field effect transistor), an IBT (insulated gate bipolar transistor), or the like is used. The heat radiating plate 72 is configured by a flat plate made of metal (for example, copper, aluminum, etc.) having high thermal conductivity. The heat radiating plate 72 corresponds to the “heat radiating member” of the present invention.

  The controller 60 and the drive current supply device 70 are stacked adjacent to each other inside the storage container 80. At this time, the lower surface of the heat radiating plate 72 is disposed at substantially the same position as the lower opening of the storage container 80. That is, the lower surface of the heat radiating plate 72 is disposed in parallel with the axial direction of the rotating shaft 21 of the motor 20. The lower surface of the heat radiating plate 72 corresponds to the “heat radiating surface having a predetermined area” of the present invention.

  Next, the drive control system of the hammer drill 100 will be described with reference to the block diagram of FIG. The drive control system of the hammer drill 100 constitutes a circuit that supplies current from the battery 130 to the three position detection elements 24 that detect the position of the rotor 23 of the motor 20 and the stator coils 22U, 22V, and 22W of the motor 20. The drive current supply device 70 and a controller 60 that controls the drive current supply device 70 are mainly configured. The drive current supply device 70 includes six switching elements 71a to 71f. As will be described later, each of the switching elements 71 is controlled by the controller 60, so that a current is supplied to a predetermined stator coil 22. Supply. The controller 60 controls the drive current supply device 70 by calculating the position of the rotor 23 based on the detection signal of the position detection element 24 and outputting a drive signal to the drive current supply device 70. The three position detection elements 24 are arranged every 120 ° in the circumferential direction of the motor 20.

  Based on the drive control system of the hammer drill 100, the controller 60 selectively applies a drive signal (gate voltage) to each of the gates of the switching elements 71a to 71f, from the following (1) to (6). Are sequentially controlled, and the rotor 23 of the motor 20 rotates once. (1) By applying a drive signal to the gates of the first switching element 71a and the sixth switching element 71f, current is passed from the first stator coil 22U to the third stator coil 22W, and (2) By applying a drive signal to the gates of the third switching element 71c and the sixth switching element 71f, current is passed from the second stator coil 22V to the third stator coil 22W, and (3) the third By applying a drive signal to the gates of the switching element 71c and the second switching element 71b, current is passed from the second stator coil 22V to the first stator coil 22U, and (4) the second switching element 71b. And by applying a drive signal to the gate of the fifth switching element 71e, the third stator coil 22W The child coil 22U is energized. (5) By applying a drive signal to the gates of the fourth switching element 71d and the fifth switching element 71e, the third stator coil 22W to the second stator coil 22V. And (6) energizing from the first stator coil 22U to the second stator coil 22V by applying drive signals to the gates of the first switching element 71a and the fourth switching element 71d. Is done.

  In driving the motor 20, not only the controller 60 and the drive current supply device 70 but also the motor 20 itself generates heat. Therefore, a cooling fan 90 is attached to the rotating shaft 21 of the motor 20 in order to dissipate heat generated from the motor 20, the controller 60, and the drive current supply device 70. The cooling fan 90 rotates to generate an air flow in the housing 10. The air flow generated in the housing 10 by the rotation of the cooling fan 90 corresponds to the “cooling air” of the present invention.

  A centrifugal fan is used as the cooling fan 90. When the cooling fan 90 is driven to rotate, the air flow sucked into the housing 10, that is, the cooling air, flows out in a direction intersecting the axial direction of the cooling fan 90 by centrifugal force. In the present embodiment, the cooling air sucked by the cooling fan 90, that is, the motor 20 is cooled by the intake air, and the cooling air that flows out from the cooling fan 90, that is, the exhaust is cooled by the controller 60 and the drive current supply device 70. It is said. The cooling air sucked into the housing 10 by the cooling fan 90 corresponds to “cooling air upstream of the fan” of the present invention, and the cooling air discharged from the cooling fan 90 is “cooling air downstream of the fan” of the present invention. ".

  In order to use the cooling air flowing out from the cooling fan 90, that is, the cooling air downstream of the fan, for cooling the electrical member 160, a cooling air guide member 161 is disposed between the motor 20 and the electrical member 160. The cooling air guide member 161 extends along the rotation axis of the motor 20 so as to cover the entire upper surface of the motor 20 and a part of the left and right side surfaces (therefore, the upper surface and side surfaces of the rotor 23) at a predetermined interval. And intersects the rotational axis of the motor 20 through the horizontal region 161a formed in a substantially arcuate cross section when viewed from the rear of the hammer drill 100, and the front surface of the motor 20 and the front surface (suction side) of the cooling fan 90. And has a substantially flat vertical area 161b extending in the direction to be fixed. A ventilation hole 161c through which cooling air flows from the motor 20 to the cooling fan 90 is formed in the vertical region 161b. As a result, the cooling air flows into the cooling fan 90 through the ventilation holes 161c and then flows out radially outward. Then, the cooling air that has flowed outward in the radial direction flows out toward the electrical component 160 through a space (passage) defined by the housing 10 and the cooling air guide member 161.

  As shown in FIG. 1, the housing 10 is formed with an air intake portion 11 and air discharge portions 12 and 13. The air intake portion 11 is configured by a plurality of openings 11 a as wind windows formed in a pair of housings constituting the housing 10. The opening 11 a is formed in the rear side surface of the motor 20 in the housing 10 in a side view of the hammer drill 100 (specifically, a region where the handgrip 120 is connected to the housing 10). The opening 11 a is a fine hole that is long in the axial direction of the motor 20, and is arranged in series in the vertical direction intersecting the axial line of the motor 20. As a result, the cooling air sucked into the housing 10 from the air intake portion 11 flows from the rear of the hammer drill 100 to the front along the axis of the motor 20.

  There are two types of air discharge units 12 and 13 for the motor and the electrical component. As shown in FIG. 2, the motor air discharge portion 12 is configured by an opening 12 a formed in the housing 10, and is formed below the cooling fan 90 in a side view of the hammer drill 100. As shown in FIG. 1, the air discharge part 13 for the electrical member is constituted by a plurality of openings 13 a formed in the housing 10, and is an upper side of the motor 20, that is, a side of the electrical member 160 in a side view of the hammer drill 100. Is formed. The opening 13 a of the air discharge unit 13 for the electrical member is a fine hole that is long in the vertical direction intersecting the axial direction of the motor 20, and is arranged in series in the axial direction of the motor 20. As a result, a part of the cooling air flowing out from the cooling fan 90 is discharged from the motor air discharge part 12 to the outside of the hammer drill 100, but most of the other is generated by the housing 10 and the cooling air guide member 161. After flowing through the enclosed space to the electrical component 160, the electrical component is discharged from the air exhaust part 13 to the outside of the hammer drill 100.

  In the hammer drill 100 configured as described above, when the trigger 121 is pulled by the user, the controller 60 outputs a drive signal to the drive current supply device 70 and the switching element 71 of the drive current supply device 70 is controlled. As a result, the drive current supply device 70 supplies current to the motor 20 from the power supply 130, and the motor 20 is driven. The rotation output of the motor 20 is converted into a linear motion in the longitudinal direction of the hammer drill 100 by the swing member 34 and then transmitted to the piston 35. As the piston 35 slides, the air in the air chamber 53 acts as an air spring, causing the striker 51 to slide. Then, the striker 51 collides with the impact bolt 52, and the impact force is transmitted to the hammer bit 200, so that the hammer bit 200 generates a striking force in the front-rear direction of the hammer drill 100. A hammer operation for processing the workpiece is performed by the impact force. On the other hand, the rotational output of the motor 20 is appropriately decelerated by the power transmission mechanism 40 and then transmitted to the hammer bit 200 to cause the hammer bit 200 to generate a rotational force. With this rotational force, a drill operation for processing the workpiece is performed. That is, in a state where the hammer bit 200 is pressed against the workpiece, the hammer drill 100 is caused to perform a hammer operation and a drill operation to process the workpiece. In addition, when processing a workpiece, you may process only with a hammer operation | movement, without performing a drill operation | movement.

  At this time, the rotating shaft 21 rotates, whereby the cooling fan 90 attached to the rotating shaft 21 rotates, and an air flow is generated in the housing 10. Specifically, the air outside the hammer drill 100 flows into the housing 10 from the opening 11 a of the air intake portion 11 due to the air flow generated in the housing 10 by the rotation of the cooling fan 90. The cooling air that has flowed into the housing 10 flows forward through the gaps between the components constituting the motor 20 and between the rotor 23 and the cooling air guide member 161 or the housing 10, and toward the suction fan 90. After flowing in the axial direction, it flows out in the radial direction. A part of the cooling air flowing out from the suction fan 90 is discharged to the outside of the hammer drill 100 from the opening 12 a of the air discharge unit 12, and most of the other passes through a space surrounded by the housing 10 and the cooling air guide member 161. It flows to the electrical component 160. Then, it flows along the heat radiating surface of the heat radiating plate 72 and is discharged from the air discharge portion 13 for the electrical component member to the outside of the hammer drill 100. In FIG. 2, the outline of the flow of the cooling air is indicated by an arrow line.

  In the case of the outer rotor type motor 20, the flange portion 22a of the stator 22 is fixed to the housing 10, the rotor 23 is formed in a bottomed cylindrical shape, and the rotating shaft 21 is fixed in a penetrating manner at the center of the bottom portion. The For this reason, although illustration is omitted for convenience, it is preferable to provide ventilation holes through which the cooling air can flow in the flange 22a of the stator 22 and the bottom of the rotor 23, respectively. Thereby, the circulation property of the cooling air with respect to the motor 20 can be improved.

  As described above, according to the present embodiment, the cooling air sucked by the cooling fan 90 is circulated in the motor 20 to cool the motor 20, and the cooling air flowing out of the cooling fan 90 is blown to the electrical component 160. Thus, the electric component 160 is cooled. Therefore, the heat generated by the motor 20 by the cooling air upstream of the fan is efficiently radiated while suppressing a decrease in the speed of the cooling air, and the controller 60 and the drive current supply device 70 of the electrical component 160 are generated by the cooling air downstream of the fan. Heat can be radiated efficiently.

  In the present embodiment, the cooling air guide member 161 is provided so as to cover the outside of the motor 20, thereby dividing the internal space of the housing 10 into a housing space for the motor 20 and a housing space for the electrical member 160. Since the cooling air that has flowed out in the radial direction from the fan 90 is guided toward the electrical member 160 by the cooling air guide member 161, the cooling air can be efficiently blown to the electrical member 160 to be cooled.

  Further, according to the present embodiment, since the outer rotor type motor in which the rotor 23 is disposed outside the stator 22 is adopted as the motor 20, the outer diameter of the rotor 23 is increased and a large rotor inertia moment is obtained. As compared with an inner rotor type motor having the same external dimensions, a large torque can be generated. If the motor is an inner rotor type motor, a speed reduction mechanism must be provided between the rotating shaft 21 and the intermediate shaft to secure a torque necessary to generate a predetermined striking force, which increases the weight. Alternatively, the hammer drill 100 may be increased in size. However, according to the present embodiment, since the motor 20 is composed of the outer rotor type motor, the speed reduction mechanism is not required, so that the weight of the machine body can be reduced and the size can be reduced. The operability of 100 can be improved.

  In the present embodiment, the rotation shaft 21 of the motor 20 is arranged coaxially with the intermediate shaft 32 of the motion conversion mechanism 30, thereby forming an empty area above the motor 20 in the housing 10. The electric component 160 is arranged in the region. For this reason, the outer shape regarding the direction which cross | intersects the major axis direction of the hammer bit 200 in the hammer drill 100 can be further reduced in size.

  In the present embodiment, the motor 20 and the electrical member 160 are arranged in parallel in the long axis direction of the hammer bit 200. For this reason, the major axis direction dimension of the hammer bit 200 in the hammer drill 100 can be shortened.

(Second embodiment of the present invention)
Next, a second embodiment of the present invention will be described with reference to FIGS. In this embodiment, both the motor 20 and the electrical component 160 are cooled by the cooling air by the intake air sucked from the outside of the hammer drill 100 by the cooling fan 90. Otherwise, the first embodiment is used. The configuration is the same as in the embodiment.

  As shown in FIG. 6, the motor 20 is constituted by an outer rotor type DC brushless motor, and the rotation shaft 21 is arranged coaxially with the intermediate shaft 32 of the motion conversion mechanism 30 and directly connected thereto. Thus, an empty area is formed above the motor 20 in the housing 10, and the electric member 160 is arranged in this empty area. As shown in FIG. 5, the housing 10 is formed with an air intake portion 14 mainly for an electrical component on the upper side of the motor 20, that is, on the lateral side of the electrical component 160 in a side view of the hammer drill 100. The member air intake 14 is constituted by a plurality of openings 14 a formed in the housing 10. The opening 13 a is a fine hole that is long in the vertical direction intersecting the axial direction of the motor 20, and is arranged in series in the axial direction of the motor 20. The air intake portion 11 formed on the rear side surface of the motor 20 as viewed from the side of the hammer drill 100 is mainly the air intake portion 11 for the motor 20.

  That is, in this embodiment, the air discharge part 13 for the electrical member in the first embodiment is mainly set as the air intake part 14 for the electrical member, and the air discharge part 12 is for the motor and the electrical member. The cooling air guide member 161 is provided as a member that divides the internal space of the housing 10 into a suction side and an exhaust side by the cooling fan 90. The configuration other than the above is the same as in the first embodiment. For this reason, about the same component as 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  According to the present embodiment configured as described above, when the cooling fan 90 is rotationally driven by the motor 20, the air outside the hammer drill 100 is converted into the motor air by the air flow generated in the housing 10. The air flows into the housing 10 from the opening 11a of the intake portion 11 and the opening 14a of the air intake portion 14 for the electrical component member. Cooling air that has flowed into the housing 10 from the motor air intake 11 flows forward through the internal space of the motor 20, while flowing into the housing 10 from the opening 14 a of the air intake 14 for the electrical component. The cooled air flows forward along the heat radiating plate 72, passes through the cooling fan 90, and is discharged from the opening 12 a of the air discharge unit 12 to the outside of the hammer drill 100. In FIG. 6, an outline of the flow of the cooling air is indicated by an arrow line. The cooling air flowing into the housing 10 from the motor air intake 11 corresponds to the “first cooling air guided to the brushless motor” in the present invention, and the housing 14 through the opening 14a of the air intake 14 for the electrical components. The cooling air flowing into 10 corresponds to the “first cooling air guided to the brushless motor” in the present invention.

  As described above, according to the present embodiment, the cooling air sucked into the housing 10 is divided into independent flows, so that the motor 20 and the electrical component 160 are introduced from the air intake portions 11 and 14. The cooling air can be individually cooled by the cooling air whose temperature is not high. For this reason, the heat generated by the controller 60 and the drive current supply device 70 of the motor 20 and the electrical member 160 of the electrical member 160 can be efficiently radiated.

  Regarding the effects obtained by adopting an outer rotor type motor as the motor 20 and the fact that the rotating shaft 21 of the motor 20 is arranged coaxially with the intermediate shaft 32 of the motion conversion mechanism 30 and is directly connected thereto, etc. This is the same as the first embodiment described above.

(Third embodiment of the present invention)
Next, a third embodiment of the present invention will be described with reference to FIG. In this embodiment, the motor 20 is an outer rotor type DC brushless motor, and the rotation axis thereof is behind the intermediate shaft 32 of the motion conversion mechanism 30 at the rear between the long axis of the hammer bit 200 and the intermediate shaft 32. They are arranged in parallel. A drive gear 37 is provided at the front end of the rotating shaft 21, and a driven gear 38 that meshes with and engages with the drive gear 37 is provided at the rear end portion of the intermediate shaft 32. The rotation output is transmitted to the intermediate shaft 32. The drive gear 37 and the driven gear 38 are provided for transmitting constant-speed rotation to the intermediate shaft 32 of the rotary shaft 21 and are set so that the intermediate shaft 32 can be driven at the same rotational speed as the rotary shaft 21.

  The electrical member 160 is arranged behind the motor 20 and is configured to be cooled by the cooling air drawn into the housing 10 from the opening 11a of the air intake portion 11 by the rotational drive of the cooling fan 90. The air intake unit 11 is configured similarly to the air intake unit described in the first embodiment. The rear of the motor 20 corresponds to the “opposite side of the cooling fan across the brushless motor” in the present invention.

  That is, in this embodiment, the rotation shaft 21 of the motor 20 is arranged in parallel to the intermediate shaft 32 and the rotation output of the motor 20 is transmitted to the intermediate shaft 32 via the drive gear 37 and the driven gear 38. In addition, the electric member 160 is disposed behind the motor 20, and the configuration other than this is the same as in the first or second embodiment.

  According to the present embodiment configured as described above, when the cooling fan 90 is rotationally driven by the motor 20, the air outside the hammer drill 100 is caused to flow in the air intake unit 11 by the air flow generated in the housing 10. It flows into the housing 10 from the opening 11a. The cooling air flowing into the housing 10 flows forward along the heat radiating plate 72 of the electrical component 160, passes through the motor 20 and the cooling fan 90, and is discharged from the opening 12 a of the air discharge unit 12 to the outside of the hammer drill 100. . In FIG. 7, the outline of the flow of the cooling air is indicated by an arrow line.

  In the case of the hammer drill 100 using the motor 20, a large current flows through the controller 60 and the drive current supply device 70 of the electrical member 160 that controls the motor 20. For this reason, the controller 60 and the drive current supply device 70 are driven by the motor 20. However, the calorific value tends to increase. On the other hand, in order to efficiently dissipate the heat generated in the narrow housing 10, it is necessary to efficiently cool the controller 60 and the drive current supply device 70 that generate a large amount of heat. Therefore, by cooling the controller 60 and the drive current supply device 70 that generate a large amount of heat on the upstream side of the motor 20 in the cooling air, the controller 60 that generates a large amount of heat due to the cooling air whose temperature is not high. In addition, the heat generated in the drive current supply device 70 can be radiated efficiently.

  In addition, about the effect obtained by employ | adopting an outer rotor type motor as the motor 20, it is the same as that of 1st Embodiment mentioned above.

  In the embodiment described above, the hammer drill 100 has been described as an example of the impact tool. However, the hammer bit 200 may be applied to an electric hammer that performs only a linear motion.

DESCRIPTION OF SYMBOLS 10 Housing 11 Air intake part 11a Opening 12 Air discharge part 12a Opening 13 Air discharge part 13a Opening 20 Motor 21 Rotating shaft 22 Stator 22a Flange part 22U, 22V, 22W Stator coil 23 Rotor 23a Permanent magnet 24 Position detection element 30 Motion conversion mechanism 32 Intermediate shaft 33 Rotating body 34 Oscillating member 35 Piston 36 Cylinder 37 Drive gear 38 Driven gear 40 Power transmission mechanism 41 First gear 42 Second gear 50 Strike element 51 Strike 52 Impact bolt 53 Air chamber 60 Controller 70 Drive Current supply device 71 Switching element 72 Heat radiation plate 73 Heat transfer material 80 Containment container 90 Cooling fan 100 Hammer drill 110 Main body 120 Hand grip 121 Trigger 130 Power supply 140 Side grip 141 Mounting ring 142 Bolt 150 Tool Holder 160 Electric member 161 Cooling air guide member 161a Horizontal region 161b Vertical region 161c Ventilation hole 200 Hammer bit

Claims (9)

An impact tool that moves a tool bit linearly in the long axis direction and performs a machining operation on a workpiece,
A brushless motor for driving the tool bit;
An electrical component for controlling the driving of the brushless motor;
A cooling fan that is rotationally driven by the brushless motor;
Have
The brushless motor has a stator, a rotor, and a rotating shaft to which the rotor is attached, and is configured as an outer rotor type in which the rotor is disposed outside the stator,
The striking tool, wherein the brushless motor and the electrical member are cooled by cooling air generated by the cooling fan. The impact tool according to claim 1,
The impact tool according to claim 1, wherein the electrical member is cooled by cooling air downstream from the cooling fan. The impact tool according to claim 1,
The electric tool and the brushless motor are both cooled by cooling air upstream of the fan that flows toward the cooling fan. The impact tool according to claim 3,
The cooling air upstream of the fan is divided into a first cooling air that is guided to the brushless motor and a second cooling air that is guided to the electrical member, and the brushless motor and the electrical member are cooled independently. Blow tool characterized by being cooled by wind. The impact tool according to claim 3,
The impact tool according to claim 1, wherein the electrical member is disposed upstream of the cooling air from the brushless motor. The impact tool according to any one of claims 1 to 5,
A driving shaft that is arranged in parallel to the long axis of the tool bit and rotated by the brushless motor, and a tool driving unit that transmits the rotation output of the driving shaft and drives the tool bit in a straight line; ,
The rotating shaft of the brushless motor and the drive shaft are arranged coaxially,
The impact tool according to claim 1, wherein the electrical component is disposed on the long axis side of the tool bit with respect to the rotation axis of the brushless motor. The impact tool according to claim 1,
A driving shaft that is arranged in parallel to the long axis of the tool bit and rotated by the brushless motor, and a tool driving unit that transmits the rotation output of the driving shaft and drives the tool bit in a straight line; ,
The rotation shaft of the brushless motor and the drive shaft are arranged in parallel,
The impact tool according to claim 1, wherein the electrical member is arranged on the opposite side of the cooling fan with the brushless motor in between in the major axis direction of the tool bit. The impact tool according to any one of claims 1 to 7,
The striking tool, wherein the cooling fan is disposed on the rotating shaft. The impact tool according to any one of claims 1 to 8,
The electrical component includes a drive current supply device for supplying a drive current to the brushless motor, a controller that controls the drive current supply device, a housing that houses the drive current supply device and the controller, and a predetermined area And a heat radiating member having a heat radiating surface, wherein at least the heat radiating surface of the heat radiating member is exposed to an air flow generated by the cooling fan.

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