JP2016068205A - Electric power tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric power tool having a housing of which size is miniaturized.SOLUTION: A hammer drill 1 to be the electric power tool includes: the housing 2; a motor 3; a power transmission mechanism 5; a control part 4; and an output part 6. The motor 3 is stored in the housing 2 and includes a body part 31 and an output shaft 32. The power transmission mechanism 5 transmits driving force of the motor 3 to a tip tool detachably provided to the output part 6. The control part 4 is stored in the housing 2 and arranged between the power transmission mechanism 5 and the body part 31 in an axial direction of the output shaft 32 to control the motor 3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power tool.

  Conventionally, a housing, an electric motor having an output shaft, a control device for controlling the electric motor, a power conversion mechanism driven by the electric motor, a tip tool that repeats rotation and reciprocation by the power conversion mechanism, A hammer drill which is an electric tool including the above is known (Patent Document 1).

JP 2012-171066 A

  In the above-described hammer drill, since the control device is disposed radially outward of the output shaft, that is, above the electric motor, the size of the housing in the radial direction is increased. In addition, the output shaft of the electric motor meshes with the gear of the power transmission mechanism and the like, and a dead space is created outside the meshed portion in the radial direction. The extra dead space is formed in the housing, which further promotes the enlargement of the housing.

  Then, an object of this invention is to provide the electric tool which reduced the size of the housing.

  In order to solve the above problems, the present invention provides a housing, a motor housed in the housing and having a main body and an output shaft, a power transmission mechanism for transmitting the driving force of the motor to a tip tool, and the housing. A power tool is provided, comprising: a control unit that is housed and disposed between the power transmission mechanism and the main body in the axial direction of the output shaft, and controls the motor.

  According to such a structure, since the control part is arrange | positioned between a power transmission mechanism and a main-body part, the space in a housing can be used effectively. In the conventional electric tool, a dead space is created by arranging an output shaft, a transmission gear, and the like of the motor between the motor and the power transmission mechanism. By disposing the control unit in such a dead space, the axial length of the motor output shaft in the housing can be shortened. Thereby, the size of the housing can be reduced.

  The said structure WHEREIN: It is preferable that the said housing has a metal casing holding the said power transmission mechanism, and at least one part of the said control part is contact | abutting to the said casing.

  According to such a configuration, since at least a part of the control unit is in contact with the metal casing, the heat of the control unit is efficiently radiated to the casing. Thereby, a control part can be cooled efficiently.

  It is preferable that the apparatus further includes a cooling fan that is rotated by the motor and disposed between the power transmission mechanism and the main body in the axial direction.

  According to such a configuration, the cooling fan can be arranged in a dead space created between the motor and the power transmission mechanism by arranging the cooling fan between the power transmission mechanism and the main body. Thereby, the axial length of the output shaft of the motor in the housing can be shortened.

  The cooling fan has a first blade protruding toward the motor and a second blade protruding toward the control unit, and the motor is generated by the first blade in the housing. It is preferable that a first air path through which the cooling air for cooling the air passes and a second air path through which the cooling air generated by the second blades and cools the control unit pass are formed.

  According to such a configuration, since the cooling air for cooling the motor and the cooling air for cooling the control unit pass through different air paths, the cooling air is compared with the case where the motor and the control unit are cooled by the same air path. The motor or the controller can be cooled in a state where the temperature of the motor is low. Thereby, a motor and a control part can be cooled efficiently.

  Moreover, it is preferable that the said 2nd air path is formed between the said casing and the said control part.

  According to such a configuration, since the second air passage is formed between the casing and the control unit, both the control unit and the casing can be cooled by the cooling air passing through the second air passage. Thereby, the heat generated by the power transmission mechanism can be radiated through the casing.

  Moreover, it is preferable that the said control part has a radiation fin, and the said radiation fin and the said casing are mutually connected.

  According to such a structure, since the radiation fin and the metal casing are connected, the control unit can be efficiently cooled. Furthermore, since the control part is connected with the casing via the radiation fin, the vibration of the casing transmitted to the control part can be reduced.

  In addition, a through hole penetrating in the axial direction is formed in the control unit, and the control unit includes a switching element disposed around the through hole, and a diode bridge disposed around the through hole. It is preferable to have.

  According to such a configuration, since the switching element and the diode bridge are arranged around the through hole, the switching element and the diode bridge can be efficiently cooled by the cooling air passing through the through hole.

  In addition, it is preferable that a hollow member that connects the control unit and the housing is further provided, and a wiring that connects the control unit and the motor is disposed in the hollow member.

  According to such a configuration, since the wiring is covered with the hollow member, the wiring can be protected from surrounding members. In particular, when the hollow member is exposed to the air path, the wiring can be protected from dust and metal pieces carried along with the cooling air.

  Further, it is preferable that a biasing member interposed between the control unit and the housing is further provided, and the control unit is held with respect to the housing by a biasing force of the biasing member.

  According to such a configuration, since the biasing member is interposed between the control unit and the housing, it is possible to prevent the vibration of the housing from being directly transmitted to the control unit.

  The urging member is preferably made of metal.

  According to such a configuration, since the biasing member is made of metal, the heat of the control unit can be efficiently radiated to the housing.

  The power transmission mechanism preferably includes a rotation transmission unit that transmits rotation of the motor to the tip tool, and a reciprocation transmission unit that converts rotation of the motor into reciprocation and transmits the rotation to the tip tool. .

  The motor is preferably a brushless motor.

  According to such a configuration, elements for controlling the brushless motor are mounted on the control unit, and these elements generate a large amount of heat, but even such elements can be sufficiently cooled.

  According to the power tool of the present invention, it is possible to provide a power tool with a reduced housing size.

Sectional drawing which shows the internal structure of the whole electric tool by embodiment of this invention. The elements on larger scale of the control part periphery of FIG. 1 of the electric tool by embodiment of this invention. The front view of the control part of the electric tool by embodiment of this invention. It is sectional drawing of the control part of the electric tool by embodiment of this invention, Comprising: (A) Sectional drawing along line IVA-IVA of FIG. 3, (B) Sectioning drawing along line IVB-IVB of FIG. .

  A power tool according to an embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, a hammer drill 1 as an example of an electric tool according to an embodiment of the present invention includes a housing 2, a motor 3, a control unit 4, a power transmission mechanism 5, an output unit 6, and a handle 7. And is used in a state where a tip tool (not shown) is attached to the output unit 6. The hammer drill 1 includes, as operation modes, a rotation hitting mode in which the tip tool rotates and hits, a rotation mode in which only the rotation is performed, and a hitting mode in which only the hitting is performed. In the following description, the side where the output unit 6 is provided with respect to the motor 3 is defined as the front direction, and the reverse direction is defined as the rear direction. The side where the power transmission mechanism 5 is provided with respect to the handle 7 is defined as the upward direction, and the opposite direction is defined as the downward direction. Further, in FIG. 1, when the hammer drill 1 is viewed from the rear direction, the right is defined as the right direction, and the reverse direction is defined as the left direction. When referring to the positional relationship, for example, when referring to parallel, orthogonal, opposite, etc., not only when it is completely parallel, orthogonal, opposite, etc., but when it is substantially parallel, substantially orthogonal, substantially opposite, etc. Shall be included.

  The housing 2 forms an outline of the hammer drill 1 and includes a motor housing 21, a gear housing 22, and a metal casing 23.

  The motor housing 21 includes a motor housing portion 21A and a handle portion 21B, and is a resin molded product, for example.

  The motor accommodating portion 21A has a substantially cylindrical shape extending in the front-rear direction, and accommodates the motor 3 therein. A motor air inlet 21a that penetrates in the left-right direction and takes in cooling air is formed in the left and right rear portions of the motor housing portion 21A. A motor exhaust port 21b is formed in the connecting portion between the motor housing portion 21A and the gear housing 22 so as to penetrate in the vertical direction and discharge the taken cooling air. A substantially L-shaped air passage in a side view passing through the motor 3 from the motor air inlet 21a to the motor air outlet 21b is defined as a first cooling air passage A. The first cooling air passage A corresponds to the first air passage of the present invention.

  The handle portion 21B is a portion that is gripped when the user uses the hammer drill 1, and extends downward from the lower rear side of the motor housing portion 21A. A power cable 21C is attached to the handle portion 21B, and a switch mechanism 21D and a trigger switch 21E are provided.

  The power cable 21C extends from the lower end of the handle portion 21B and is configured to be electrically connectable to a commercial power source (not shown). The switch mechanism 21 </ b> D is accommodated in the handle portion 21 </ b> B and is electrically connected to the motor 3 via the control unit 4. The trigger switch 21E is provided on the upper front side of the handle portion 21B, and the control unit 4 changes the rotation speed of the motor 3 according to the pulling amount of the trigger switch 21E.

  The gear housing 22 has a substantially cylindrical shape extending in the front-rear direction, and is connected to the front end portion of the motor housing portion 21A. A casing 23 and a power transmission mechanism 5 are accommodated in the gear housing 22. As shown in FIG. 2, a first gear intake port 22 a that penetrates in the vertical direction and takes in cooling air is formed in the rear and upper portion of the gear housing 22. A second gear intake port 22b that penetrates in the vertical direction and takes in cooling air is formed in the rear and lower portion of the gear housing 22. Behind the first gear intake port 22a is formed a first gear exhaust port 22c that penetrates in the vertical direction and discharges the cooling air taken in from the first gear intake port 22a. A second gear exhaust port 22d is formed behind the second gear intake port 22b so as to penetrate in the vertical direction and exhaust the cooling air taken in from the second gear intake port 22b. A substantially U-shaped air passage from the first gear intake port 22a to the first gear exhaust port 22c is defined as a second cooling air passage B. A substantially U-shaped air passage in a side view passing through the periphery of the control unit 4 from the second gear intake port 22b to the second gear exhaust port 22d is defined as a third cooling air passage C. The second cooling air passage B and the third cooling air passage C correspond to the second air passage of the present invention.

  The casing 23 is accommodated in the gear housing 22, holds the rear part of the power transmission mechanism 5, and plays a role of radiating heat generated in the power transmission mechanism 5. The casing 23 is integrally provided with an insertion portion 23A that protrudes rearward. A ball bearing 23B is provided in the insertion portion 23A, and an output shaft 32 described later is rotatably supported. The rear surface of the casing 23 forms a guide portion 23 </ b> C that guides the cooling air of the second cooling air passage B and the third cooling air passage C in a substantially L shape in a side view. Since the guide portion 23C guides the cooling air in a substantially L shape when viewed from the side, the surface area of the casing 23 exposed to the cooling air can be increased, and the casing 23 can be efficiently cooled.

  In the casing 23, a first casing intake port 23a is formed at a position corresponding to the first gear intake port 22a, and a second casing intake port 23b is formed at a position corresponding to the second gear intake port 22b. A first casing exhaust port 23c is formed at a position corresponding to the exhaust port 22c, and a second casing exhaust port 23d is formed at a position corresponding to the second gear exhaust port 22d. Here, “corresponding” means that the respective positions coincide with each other. The first casing intake port 23a and the first casing exhaust port 23c form part of the second cooling air passage B. The second casing intake port 23b and the second casing exhaust port 23d form part of the third cooling air passage C.

  As shown in FIG. 1, the motor 3 is a brushless motor, and includes a main body portion 31, an output shaft 32 that protrudes forward from the main body portion 31, and a cooling fan 33. The output shaft 32 is rotatably supported on the housing 2 by a ball bearing 31A supported by the motor housing 21 and a ball bearing 23B. The motor air inlet 21a is located in the vicinity of the ball bearing 31A. A pinion gear 32 </ b> A that transmits rotation to the power transmission mechanism 5 is provided at the front end portion of the output shaft 32.

  The cooling fan 33 is a radial fan, and is coaxially fixed between the pinion gear 32 </ b> A of the output shaft 32 and the main body 31. As shown in FIG. 2, the cooling fan 33 includes a fan main body 33A fixed to the output shaft 32, a first blade 33B protruding from the fan main body 33A toward the main body 31 (FIG. 1), and a fan main body 33A. And a second blade 33C that protrudes toward the power transmission mechanism 5. The second blade 33C is provided with a sensor magnet 33D that can face a hall element 44 described later in the front-rear direction. The motor exhaust port 21b is located radially outward of the first blade 33B. The cooling air sucked from the motor intake port 21a is bent at a right angle by the first blade 33B and discharged from the motor exhaust port 21b.

  The controller 4 is located between the main body 31 and the casing 23 in the axial direction of the output shaft 32. Specifically, in the hammer drill 1, the power transmission mechanism 5, the casing 23, the control unit 4, and the motor 3 are arranged in this order from the front to the rear in the housing 2.

  As shown in FIG. 3, the control unit 4 includes a control board 41, a plurality of IGBTs 42, heat radiation fins 43, a hall element 44, and a diode bridge 45. The control board 41 is disposed so as to extend in the vertical direction. The control board 41 is provided with a microcomputer (not shown) and receives a signal from the hall element 44. The microcomputer detects the number of rotations of the motor 3 based on the signal from the hall element 44 and controls the motor 3. A substantially circular through hole 41a penetrating in the front-rear direction is formed in a substantially central portion of the control board 41, and an insertion portion 23A is inserted therein. The insertion portion 23A and the through hole 41a are separated from each other in the radial direction of the through hole 41a. Thereby, it is possible to suppress the vibration of the casing 23 from being transmitted to the control board 41. The through hole 41a forms part of the second cooling air passage B and part of the third cooling air passage C. Around the through hole 41a, a plurality of IGBTs 42, heat radiation fins 43, Hall elements 44, and diode bridges 45 are arranged.

  A plurality of IGBTs 42 (six in this embodiment) are provided on the upper front surface of the control board 41. The radiating fin 43 covers the first radiating fin 43 </ b> A in contact with the right three IGBTs 42 among the six IGBTs 42, the second radiating fin 43 </ b> B in contact with the three left IGBTs 42, and the diode bridge 45. The third heat dissipating fin 43C. As shown in FIG. 4A and FIG. 4B, each radiating fin 43 is substantially U-shaped when viewed in the vertical direction, and the substantially U-shaped internal space forms part of the second cooling air passage B. The two IGBTs 42 in which the first heat dissipating fins 43A are in contact from the right side and the two IGBTs 42 in which the second heat dissipating fins 43B are in contact from the left side are separated from each other in the left-right direction, and the second cooling air passage is between them. Part of B. The cooling air passes through one surface of each IGBT 42 in the left-right direction, and the radiation fins 43 are in contact with the other surface. Thereby, the IGBT 42 having a relatively large calorific value among the elements on the control board 41 can be efficiently cooled. The IGBT 42 corresponds to the switching element of the present invention.

  A metal first leaf spring 46 is provided between the front end surfaces of the first and second radiating fins 43 </ b> A and 43 </ b> B and the casing 23. The first leaf spring 46 urges the control board 41 backward via the first radiation fins 43A and the second radiation fins 43B.

  A hollow member 47 that connects the rear surface and the motor housing 21 is provided on the rear surface of the control board 41. A wiring 48 that electrically connects the control unit 4 and the motor 3 is disposed inside the hollow member 47. As shown in FIG. 2, the hollow member 47 is exposed to the second cooling air passage B, and the cooling air passes therethrough.

  The hall element 44 is an element for detecting the number of revolutions of the motor 3 and is provided below the through hole 41a. The diode bridge 45 is located below the Hall element 44, and the outer peripheral surface thereof is covered with the third radiating fins 43C (FIG. 3). The diode bridge 45 serves as a rectifier that converts the AC power from the power cable 21C into a DC power. As shown in FIG. 4B, a metal second leaf spring 49 is provided between the front end surface of the third radiating fin 43 </ b> C and the casing 23. The second leaf spring 49 urges the control board 41 backward via the third heat radiation fins 43C.

  A damper 50 that connects the rear surface and the motor housing 21 is provided below the rear surface of the control board 41. Since the damper 50 is an elastic member, the vibration of the motor housing 21 can be prevented from being transmitted to the control board 41. The control board 41 is urged rearward by the first plate spring 46 and the second plate spring 49, so that the movement in the front-rear direction and the up-down direction is restricted and held on the housing 2. The first leaf spring 46 and the second leaf spring 49 correspond to the biasing member of the present invention.

  As shown in FIG. 1, the power transmission mechanism 5 includes an intermediate shaft 51, a sleeve 52, a clutch mechanism 53, a transmission gear 54, a motion conversion unit 55, a cylinder 56, a piston 57, and a striker 58. , And an intermediate element 59.

  As shown in FIG. 1, the intermediate shaft 51 extends in the front-rear direction in parallel with the output shaft 32, and is rotatably supported by the gear housing 22. A sleeve 52 is provided at the front portion of the intermediate shaft 51, a motion converting portion 55 is provided at the rear portion, and a clutch mechanism 53 is provided at a portion between the sleeve 52 and the motion converting portion 55. .

  The sleeve 52 and the intermediate shaft 51 can rotate together and mesh with the transmission gear 54. The rotational force of the intermediate shaft 51 is transmitted to the sleeve 52 via the clutch mechanism 53. The transmission gear 54 meshes with the sleeve 52 and is fixed to the cylinder 56, and transmits the rotation of the sleeve 52 to the cylinder 56.

  The clutch mechanism 53 switches between a rotation impact mode in which the rotation of the intermediate shaft 51 is transmitted to the sleeve 52 and the motion conversion unit 55, a rotation mode in which only the sleeve 52 is transmitted, and an impact mode in which only the motion conversion unit 55 is transmitted. Yes. The operation mode of the hammer drill 1 is switched based on the operation of the clutch mechanism 53.

  The motion conversion unit 55 includes a rotation unit 55A, a ball 55B, and an arm unit 55C.

  The rotating portion 55A can rotate integrally with the intermediate shaft 51, and has a groove 55a recessed inward. The ball 55B is engaged with a receiving portion 55b formed in the groove 55a and the arm portion 55C. When the rotating portion 55A rotates, the ball 55B moves along the groove 55a. Thereby, the upper end part of the arm part 55C reciprocates in the front-rear direction, and the rotational movement of the rotating part 55A is converted into the reciprocating movement of the tip part of the arm part 55C.

  The upper end portion of the arm portion 55C is connected to the piston 57, and reciprocates in the front-rear direction in the cylinder 56 in conjunction with the reciprocating motion of the arm portion 55C. The cylinder 56 accommodates a piston 57 and an intermediate element 59. The striker 58 has a substantially cylindrical shape, and is provided in the piston 57 so as to be slidable in the front-rear direction. An air chamber 57 a is defined by the rear end surface of the striker 58 and the inner peripheral surface of the piston 57. The intermediate element 59 has a substantially cylindrical shape and is positioned in front of the striker 58. The intermediate shaft 51, the sleeve 52, the clutch mechanism 53, the transmission gear 54, and the cylinder 56 correspond to a rotation transmission unit of the present invention. The intermediate shaft 51, the clutch mechanism 53, the motion conversion unit 55, the cylinder 56, the piston 57, the striker 58, and the intermediate member 59 correspond to the reciprocation transmission unit of the present invention.

  The output unit 6 is provided in front of the gear housing 22 and includes tool holding means 61 that holds the tip tool in a detachable manner. The handle 7 extends downward from the rear of the output unit 6.

  Next, the operation of the hammer drill 1 will be described.

  When the user holds the handle portion 21B and the handle 7 and pulls the trigger switch 21E while pressing the tip tool against a workpiece (not shown), electric power is supplied to the motor 3 and the output shaft 32 rotates.

  As the cooling fan 33 fixed to the output shaft 32 rotates, the cooling air is taken in from the motor air inlet 21a by the first blade 33B. The taken cooling air cools the motor 3 while passing through and around the motor 3, flows along the first cooling air passage A, and is discharged to the outside from the motor exhaust port 21b.

  The cooling air is taken in from the first gear intake port 22a by the rotation of the second blade 33C. The taken-in cooling air passes through the first casing intake port 23a and passes through the through hole 41a while cooling the IGBT 42, the first radiating fin 43A, and the second radiating fin 43B, as shown in FIG. At this time, since the cooling air flows along the guide portion 23C, the casing 23 is also cooled at the same time. The cooling air passes through the periphery of the hollow member 47 while cooling the control board 41 along the second cooling air passage B, and is discharged to the outside from the first gear exhaust port 22c.

  Similarly, the cooling air is taken in from the second gear intake port 22b by the rotation of the second blade 33C. The taken cooling air passes through the second casing intake port 23b, and passes through the through hole 41a while cooling the third radiating fin 43C, as shown in FIG. At this time, since the cooling air flows along the guide portion 23C, the casing 23 is also cooled at the same time. Thereafter, the cooling air passes around the damper 50 while cooling the control board 41 along the third cooling air passage C, and is discharged to the outside from the second gear exhaust port 22d.

  The rotational force of the output shaft 32 is transmitted to the intermediate shaft 51 through the pinion gear 32A. In the rotation hitting mode, when the intermediate shaft 51 rotates, a rotational force is transmitted to the cylinder 56 via the sleeve 52, and the cylinder 56 and the output unit 6 rotate. At the same time, as the intermediate shaft 51 rotates, the arm portion 55C of the motion converting portion 55 reciprocates in the front-rear direction.

  When the arm portion 55C starts to reciprocate and the piston 57 connected to the arm portion 55C moves rearward, the air in the air chamber 57a expands and the pressure decreases. At this time, since the pressure in the space defined between the striker 58 and the intermediate piece 59 is higher than the pressure in the air chamber 57a, the striker 58 moves rearward.

  The piston 57 moves forward by a reciprocating motion, and the striker 58 moves backward to compress the air in the air chamber 57a. The striker 58 is accelerated forward as the compressed air in the air chamber 57a expands. The intermediate element 59 is hit by the impact element 58, and an impact force is applied to the tip tool via the intermediate element 59. Then, the piston 57 moves backward again by the reciprocating motion, and the striker 58 moves backward.

  Thus, the arm portion 55C reciprocates, whereby the piston 57 reciprocates and the air in the air chamber 57a repeats compression and expansion. Thereby, the striker 58 reciprocates in the front-rear direction, and the strike force is transmitted to the tip tool via the intermediate piece 59. In the rotary impact mode, the work material is machined by rotating and hitting the tip tool.

  In the rotation mode, pulling the trigger switch 21E rotates the output shaft 32, and the rotational force of the output shaft 32 is transmitted to the intermediate shaft 51 via the pinion gear 32A.

  As the intermediate shaft 51 rotates, a rotational force is transmitted to the cylinder 56 via the sleeve 52 and the transmission gear 54, and the tip tool rotates. At this time, since the clutch mechanism 53 does not transmit the rotation of the intermediate shaft 51 to the motion converting unit 55, the arm unit 55C does not reciprocate. Thereby, only the rotational force is transmitted to the tip tool.

  In the hit mode, the output shaft 32 rotates by pulling the trigger switch 21 </ b> E, and the rotational force of the output shaft 32 is transmitted only to the motion conversion unit 55 via the clutch mechanism 53. The rotation of the output shaft 32 is converted into a reciprocating motion by the motion converter 55 and transmitted to the cylinder 56.

  As the cylinder 56 reciprocates, only the striking force is transmitted to the tip tool via the striking element 58 and the intermediate element 59.

  According to such a configuration, since the control unit 4 is arranged between the power transmission mechanism 5 and the main body 31 of the motor 3, the space in the housing 2 can be used effectively. In the conventional hammer drill, a dead space is created by arranging the output shaft of the motor, the transmission gear, and the like between the motor and the power transmission mechanism. By arranging the control unit 4 in such a dead space, the axial length of the output shaft 32 of the motor 3 in the housing 2 can be shortened.

  According to such a configuration, since the first leaf spring 46 and the second leaf spring 49 which are at least a part of the control unit 4 are in contact with the metal casing 23, the heat of the control unit 4 is efficiently transferred to the casing. 23 is dissipated. Thereby, the control part 4 can be cooled efficiently.

  According to such a configuration, the radiating fins 43 are connected to the metal casing 23 via the first leaf springs 46 and the second leaf springs 49, so that the control unit 4 can be efficiently cooled. it can. Furthermore, since the control unit 4 is connected to the casing 23 via the radiation fins 43, the first plate springs 46, and the second plate springs 49, vibration of the casing 23 transmitted to the control unit 4 can be reduced. .

  According to such a configuration, by disposing the cooling fan 33 between the power transmission mechanism 5 and the motor 3, the cooling fan 33 can be disposed in the dead space created between the motor 3 and the power transmission mechanism 5. it can. Thereby, the size of the output shaft 32 in the housing 2 in the axial direction can be reduced.

  According to such a configuration, since the cooling air that cools the motor 3 and the cooling air that cools the control unit 4 pass through different air paths, the motor 3 and the control unit 4 are compared with the case where they are cooled by the same air path. Then, the motor 3 or the control unit 4 can be cooled in a state where the temperature of the cooling air is low. Thereby, the motor 3 and the control part 4 can be cooled efficiently.

  According to such a configuration, since the second cooling air passage B and the third cooling air passage C are formed between the casing 23 and the control unit 4, the second cooling air passage B and the third cooling air passage C are provided. Both the control unit 4 and the casing 23 can be cooled by the cooling air passing through. Thereby, the heat generated by the power transmission mechanism 5 can be radiated through the casing 23.

  According to such a configuration, since the IGBT 42 and the diode bridge 45 are arranged around the through hole 41a, the IGBT 42 and the diode bridge 45 can be efficiently cooled by the cooling air passing through the through hole.

  According to such a configuration, since the wiring 48 is covered with the hollow member 47, the wiring 48 can be protected from surrounding members. Furthermore, since the hollow member 47 is located in the air path, the wiring can be protected from dust and metal pieces carried along with the cooling air.

  According to such a configuration, since the first plate spring 46 and the second plate spring 49 are interposed between the control unit 4 and the housing 2, the vibration of the housing 2 is prevented from directly propagating to the control unit 4. it can.

  According to such a configuration, since the first plate spring 46 and the second plate spring 49 are made of metal, the heat of the control unit 4 can be efficiently radiated to the housing 2.

  According to such a configuration, the IGBT 42 for controlling the motor 3 which is a brushless motor is mounted on the control unit 4, and these elements generate a large amount of heat, but even such elements are sufficiently cooled. be able to.

  The power tool according to the present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the gist of the invention described in the claims.

  In the above-described embodiment, the control unit 4 includes only one control board 41. However, the present invention is not limited to this. For example, the control unit may include two control boards. In that case, two control boards may be opposed to each other in the axial direction of the output shaft of the motor, one is placed in front of the cooling fan, and the other is placed between the cooling fan and the motor body. You may arrange | position between. In this case, the position of the rotor can be directly detected by providing a Hall element on the other sheet.

  In the above-described embodiment, the motor 3 is a brushless motor, but can be applied to a hammer drill equipped with a commutator motor. In this case, an element such as a triac may be provided in the control unit 4.

  In the above-described embodiment, the control unit 4 is held by the first plate spring 46 and the second plate spring 49, the hollow member 47, and the damper 50, but is not limited thereto. For example, a rib may be protruded inward from the housing, and the control unit may be held by the rib. In this case, it is preferable to insert an elastic body for vibration isolation between the control board and the rib.

  In the above-described embodiment, the cooling fan 33 is located in front of the main body 31 of the motor 3, but a cooling fan may be arranged behind the motor.

  In the above-described embodiment, the power cable 21C is driven by being connected to a commercial power source. However, a battery pack may be detachably provided as a power source.

  In the above-described embodiment, the leaf spring is used as means for urging the control unit 4, but the present invention is not limited to this. For example, a metal spring may be used, or a resin rubber or a leaf spring may be used. By using an elastic body made of resin, electrical connection between the casing and the control board can be reduced. Moreover, you may connect a radiation fin and a casing directly, without inserting a leaf | plate spring etc. Thereby, the cooling efficiency can be further increased.

  In the above-described embodiment, the hammer drill is used as an example of the electric tool, but the invention is not limited to this as long as the power transmission mechanism is located in the axial direction of the output shaft of the motor. For example, it can be applied to a grinder, a multi-cutter, and a saber saw.

1 .... hammer drill 2 .... housing 3 .... motor 4 .... control part 5 .... power transmission mechanism 6 .... output part 7 .... handle 21 .... motor housing 22 .... gear housing 23 .... casing 31 .... main body Portion 32 ··· Output shaft 33 ··· Cooling fan 33A · · First blade 33B · · Second blade 41 · · Control board 41a · · Through hole 42 · · IGBT 43 · · Radiation fin 44 · · Hall element 45 · · Diode bridge 46 .. First leaf spring 49 .. Second leaf spring 51 .. Intermediate shaft 52 .. Sleeve 53 .. Clutch mechanism 54 .. Transmission gear 55 .. Motion conversion part 56.・ ・ Batter 59 ・ ・ Meson

Claims (12)

A housing;
A motor housed in the housing and having a main body and an output shaft;
A power transmission mechanism for transmitting the driving force of the motor to the tip tool;
A power tool, comprising: a control unit that is housed in the housing and disposed between the power transmission mechanism and the main body in the axial direction of the output shaft, and controls the motor. The housing has a metal casing that holds the power transmission mechanism,
The power tool according to claim 1, wherein at least a part of the control unit is in contact with the casing.   The electric tool according to claim 2, further comprising a cooling fan that is rotated by the motor and disposed between the power transmission mechanism and the main body in the axial direction. The cooling fan has a first blade that protrudes toward the motor, and a second blade that protrudes toward the control unit,
The housing has a first air passage through which cooling air generated by the first blades and cools the motor passes; a second air passage through which cooling air generated by the second blades and cools the control unit passes; The power tool according to claim 3, wherein the power tool is formed.   The power tool according to claim 4, wherein the second air path is formed between the casing and the control unit. The control unit has a radiation fin,
The power tool according to claim 5, wherein the radiating fin and the casing are connected to each other. The control unit is formed with a through hole penetrating in the axial direction,
The said control part has a switching element arrange | positioned around the said through-hole, and a diode bridge arrange | positioned around the said through-hole, The any one of Claim 1 to 6 characterized by the above-mentioned. Power tools. A hollow member connecting the control unit and the housing;
The electric tool according to any one of claims 1 to 7, wherein a wiring connecting the control unit and the motor is disposed in the hollow member. A biasing member interposed between the control unit and the housing;
The power tool according to claim 1, wherein the control unit is held with respect to the housing by a biasing force of the biasing member.   The power tool according to claim 9, wherein the biasing member is made of metal.   The power transmission mechanism includes: a rotation transmission unit that transmits rotation of the motor to the tip tool; and a reciprocation transmission unit that converts rotation of the motor into reciprocation and transmits the rotation to the tip tool. The power tool according to any one of claims 1 to 10.   The electric tool according to any one of claims 1 to 11, wherein the motor is a brushless motor.

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