JP2017213661A - Electric tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric tool which enables easy arrangement of a lead wire for supplying electric power to a stator coil of a brushless motor and reduction of its length in a fore and aft direction.SOLUTION: An electric tool includes a brushless motor 4 having an axis set to a fore and aft direction within a housing. Further, a working tool driven by the brushless motor 4 is disposed at a front side. A coil substrate 33, with which a lead wire 35 for supplying electric power to a stator coil 25 of the brushless motor 4 is connected and the stator coil 25 is connected, is disposed in front of the stator coil 25.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an electric tool provided with a brushless motor.

  As an electric tool provided with a brushless motor, for example, there are those described in Patent Documents 1 and 2 below. In these electric tools, a substrate is disposed on the rear side of the brushless motor, and the substrate and the stator coil of the brushless motor are connected. A lead wire for supplying power to the stator coil is connected to the substrate.

  However, the lead wire is thick because it is for power feeding, and the board is located on the rear side of the brushless motor, and the housing is close to the rear side, so it is difficult to route the lead wire to the board. The housing and the lead wire are likely to interfere with each other. Further, there is a problem that the rear end portion of the housing tends to have a shape extending rearward, and the size (front-rear length) of the power tool tends to increase.

JP 2010-207992 A JP 2010-76051 A

  Therefore, the present invention has been made in view of the above-described conventional problems, and it is an object of the present invention to provide an electric tool that can easily lead a lead wire for supplying power to a stator coil of a brushless motor and can suppress the longitudinal length. Let it be an issue.

  The present invention has been made to solve the above-mentioned problems, and an electric tool according to the present invention includes a brushless motor having an axis in the front-rear direction inside a housing, and a work tool driven by the brushless motor is a front side. In the electric tool arranged in the above, the lead wire for supplying power to the stator coil of the brushless motor is connected and the coil substrate to which the stator coil is connected is arranged on the front side of the stator coil. .

  In the electric tool having such a configuration, a coil substrate to which a lead wire for supplying power to the stator coil of the brushless motor is connected is disposed on the front side of the stator coil. The front side of the stator coil is at a position where it is less likely to interfere with the housing as compared to the rear side, and there is room in the space. Therefore, the lead wire can be easily connected to the coil substrate.

  In particular, a fan for cooling the brushless motor is disposed on the front side of the coil substrate, a vent is formed in the housing portion facing the outer periphery of the fan, and the front surface of the coil substrate is protected with an insulating material. Preferably it is. Thus, the stator coil can be efficiently cooled by disposing the fan and providing the vent in the housing. In particular, since the fan is positioned on the front side of the brushless motor, the hot air discharged from the vents is far from the operator. Moreover, it is easy to suppress the longitudinal length of the electric tool. On the other hand, if a vent is formed in the housing, foreign matter may enter through the vent, but the front of the coil substrate is protected with an insulating material, so even if foreign matter enters through the vent. A short circuit in the coil substrate is prevented.

  In addition, a fan for cooling the brushless motor is provided, and the fan includes a wing portion located on the outer peripheral portion, a mounting portion on the motor shaft located on the inner peripheral portion, and an intermediate portion connecting the wing portion and the mounting portion. A through hole is formed in the central portion of the coil substrate, the fan wing is located on the front side of the coil substrate, and the fan mounting portion is located on the rear side of the wing portion. The rear part is inserted through the through hole of the coil substrate, and the intermediate part is a cylindrical shape that opens to the front side, and is arranged so that at least the rear part of the bearing that supports the front part of the motor shaft enters inside the intermediate part. It is preferable. Since the fan is positioned on the front side of the brushless motor as described above, the hot air discharged from the vents is far from the operator, and the front and rear length of the power tool can be easily suppressed. On the other hand, if the coil substrate, the fan, and the bearing are arranged in order on the front side of the stator coil, the longitudinal length tends to increase. Therefore, the mounting portion of the fan is shifted rearward with respect to the wing portion, and the mounting portion is inserted and arranged in the through hole of the coil substrate, and the intermediate portion of the fan is formed in a cylindrical shape and has a bearing inside thereof. At least the rear part of the is inserted and arranged. Thus, by arranging the coil substrate, the fan, and the bearing so as to overlap, the longitudinal length can be made compact.

  The intermediate part of the fan has a shape that increases in diameter toward the front side, the intermediate part is inserted through the through hole of the coil substrate, and the entire bearing is inserted inside the intermediate part. More preferably, it is configured. By making the fan's middle part into a shape that increases in diameter toward the front side, a large opening on the front side can be secured, while the rear part of the middle part can be made small in diameter and inserted through the through hole of the coil substrate. It becomes easy. And by inserting and arranging the entire bearing inside the intermediate portion, the longitudinal length can be made even more compact.

  Furthermore, it is preferable that a sensor substrate provided with a Hall element for detecting the rotation of the rotor of the brushless motor is disposed on the rear side of the brushless motor separately from the coil substrate. If the sensor substrate provided with the Hall element is provided separately from the coil substrate, the degree of freedom of design is increased, for example, the degree of freedom of the shape of the coil substrate is increased.

  If the sensor substrate is separated from the coil substrate, the Hall element can be easily disposed at a position close to the motor shaft, and the rotation of the rotor can be easily detected. Also, by separating the sensor substrate from the coil substrate, it becomes easy to enlarge the through hole of the coil substrate, and the rear part of the fan can be easily inserted and arranged in the through hole, and the front opening of the intermediate part The diameter of the part can also be increased, and the bearing can be disposed deeply into the rear side, so that the longitudinal length can be easily compressed. Since the signal line connected to the sensor substrate is thinner and softer than the lead wire, wiring is easy.

  As described above, since the coil substrate is disposed on the front side of the stator coil, it is easy to route the lead wire to the coil substrate. In addition, since the lead wire is less likely to interfere with the housing, the front and rear length of the power tool can be made compact.

The side view which looked at the electric tool in one Embodiment of this invention from the right side. The perspective view which looked at the same electric tool from diagonally right back. The side view which looked at the state which removed the right main cover of the electric tool from the right side. The perspective view which looked at the state which removed the right main cover of the electric tool from diagonally right forward. The perspective view which looked at the state which removed the rear cover of the electric tool from diagonally right rear. Sectional drawing which cut | disconnected the electric tool with the cutting line of the up-down direction. AA sectional drawing of FIG. FIG. 8 is an enlarged view of a main part of FIG. The perspective view which looked at the stator of the brushless motor of the electric tool from diagonally forward.

  Hereinafter, an electric tool according to an embodiment of the present invention will be described with reference to FIGS. 1 to 9. The electric tool in the present embodiment is an impact driver that is used with a tip tool (not shown) attached to the tip portion. A sleeve 6 configured to be able to reciprocate back and forth is provided on the outer peripheral surface of the tip portion. The sleeve 6 is pulled forward, the rear end portion of the tip tool is inserted into the chuck hole 7, and the hand is released from the sleeve 6. The sleeve 6 automatically returns to the rear and the tip tool is fixed. The chuck hole 7 has a hexagonal shape in sectional view, and the attachment portion at the rear portion of the tip tool also has a hexagonal shape in sectional view.

  The electric tool includes a battery mounting portion 1 for detachably mounting a battery pack (not shown), and the battery pack is mounted on the lower surface of the battery mounting portion 1. A grip portion 2 extends upward from the upper surface of the battery mounting portion 1. A head portion 3 is provided above the grip portion 2. The head part 3 has a shape that is long in the front-rear direction as a whole, and the grip part 2 is located at the center part of the head part 3 in the front-rear direction. The head unit 3 includes a brushless motor 4. A tip tool is attached to the tip portion of the head portion 3, and the attached tip tool is rotationally driven by the brushless motor 4.

  A trigger switch 5 is provided on the upper front surface of the grip portion 2. The trigger switch 5 is normally urged forward and is in a protruding state, and is configured to be pushed backward from the state, that is, configured to be pulled forward from the operator side. When the button is pulled, the power is turned on and the brushless motor 4 is operated. When the trigger switch 5 is released, the brush returns to the original protruding position, the power is turned off, and the brushless motor 4 is stopped. Further, the rotation speed of the brushless motor 4 increases according to the pulling amount of the trigger switch 5.

  The electric power tool includes a housing as an exterior material, and each component including the brushless motor 4 is accommodated inside the housing. The housing is composed of a plurality of divided covers, and the covers are screwed together to form an integral hollow shape. Specifically, the housing includes a front cover 10, a rear cover 11, and a pair of left and right main covers 12. 3 and 4 show a state where the right main cover 12 is removed. FIG. 5 shows a state where the rear cover 11 is removed.

  The brushless motor 4 is located at the rearmost part of the head part 3, and is fixed to the inside of the housing so that its axis is in the front-rear direction. The motor shaft 20 of the brushless motor 4 is coaxial with the chuck hole 7 and is in a straight line. The brushless motor 4 includes a rotor 21 and a stator. The rotor 21 includes a permanent magnet and rotates integrally with the motor shaft 20. The stator includes a stator core 23, an insulating member 24, and a stator coil 25. The stator has a cylindrical shape as a whole and is fixedly attached to the housing, and the rotor 21 is rotatably disposed inside the stator.

  A cylindrical bearing holding portion 13 protrudes from the center of the inner surface of the rear cover 11 toward the front side, and a rear bearing 14 that supports the rear portion of the motor shaft 20 is fitted from the front side. The rear bearing 14 supports a rear end portion of the motor shaft 20, and the motor shaft 20 extends forward from the rear bearing 14 by a predetermined length. On the rear surface of the rear cover 11, that is, the rear end surface of the head portion 3, an intake side air vent 15 is formed. Although the arrangement and shape of the air inlet 15 on the intake side may be various, in this embodiment, a total of four places are arranged at intervals of 90 degrees on the outer peripheral side of the bearing holder 13. A brushless motor 4 is disposed on the front side of the rear cover 11.

  A sensor substrate 30 is fixed to the rear end portion of the stator. Specifically, the sensor substrate 30 is fixed to the rear end surface of the insulating member 24 of the stator from the rear side. Positioning pins 26 project from the rear end surface of the insulating member 24 of the stator as shown in FIGS. 5 and 9, and the sensor substrate 30 is positioned by the positioning pins 26. The sensor substrate 30 is circular, and a through hole 30a is formed at the center thereof, and the bearing holder 13 is inserted into the through hole 30a from the rear side. Therefore, the rear bearing 14 is located inside the through hole 30a of the sensor substrate 30. The through hole 30a of the sensor substrate 30 is smaller than the inner diameter of the stator. Further, the sensor substrate 30 is located on the front side of the air inlet 15 on the intake side of the rear cover 11. The sensor board 30 is located between the intake-side vent 15 and the stator coil 25 so as to block the intake-side vent 15 and the stator coil 25, and covers the rear side of the stator coil 25. . The sensor board 30 is provided with a vent hole 30b as shown in FIG. 5, but the vent hole 30b is provided with a position offset with respect to the vent hole 15 on the intake side of the rear cover 11.

  A plurality of Hall elements (Hall ICs) (not shown) for detecting the rotation of the rotor 21, specifically, the rotation of the magnets of the rotor 21, are attached to the front surface of the sensor substrate 30. The sensor board 30 is connected to a signal line 32 for sending the output signal of the Hall element to the control circuit board 31. In the case of the three-phase brushless motor 4, for example, three Hall elements are provided, and a total of six signal lines 32 are connected corresponding to the number of Hall elements.

  On the other hand, a coil substrate 33 is fixed to the front end portion of the stator. Specifically, the coil substrate 33 is fixed to the front end surface of the insulating member 24 of the stator. As shown in FIG. 9, positioning pins 27 project from the front end surface of the insulating member 24 of the stator, and the coil substrate 33 is positioned by the positioning pins 27. A lead wire 35 for supplying power to the stator coil 25 is connected to the coil substrate 33. In the case of the three-phase brushless motor 4, there are three lead wires 35 that are connected to the coil substrate 33. Specifically, the coil substrate 33 is circular as a whole, and a through hole 33a is formed at the center thereof. The through hole 33a of the coil substrate 33 is larger and larger in diameter than the through hole 30a of the sensor substrate 30, and the diameter is equal to or slightly larger than the inner diameter of the stator. The front side of the stator coil 25 is covered with a coil substrate 33.

  A substrate extension 34 extends downward from the lower end of the coil substrate 33 in the form of a tongue, and a lead wire 35 is connected to the substrate extension 34. That is, the board extension 34 is a lead wire connecting portion for connecting the lead wire 35. The lead wire 35 is connected to the rear surface of the board extension 34. Accordingly, the upper end portion of the lead wire 35, that is, the end portion on the connection side with the coil substrate 33, once goes backward from the rear surface of the substrate extension 34 of the coil substrate 33, and then curves downward. It extends. The stator coil 25 is connected to the coil substrate 33. In the case of the three-phase brushless motor 4, for example, a total of six stator coils 25 are provided, which are respectively connected to the coil substrate 33 and connected to the coil substrate 33. The stator coil 25 is connected to the outer peripheral portion of the coil substrate 33, and a soldering portion (illustrated) soldered to the outer peripheral portion of the front surface of the coil substrate 33 when the stator coil 25 is connected to the coil substrate 33. (Omitted) exists.

  The front surface of the coil substrate 33 is protected by a protective cover 36 made of an insulating material. The protective cover 36 has a shape corresponding to the shape of the coil substrate 33, and since the coil substrate 33 is generally annular having the through hole 33a, the protective cover 36 is also generally annular having the through hole 36a. . Further, as described above, since the substrate extension 34 is extended downward at the lower end portion of the outer peripheral edge of the coil substrate 33, the protective cover 36 has a shape corresponding to the extension. An extension cover portion 37 that covers the substrate extension 34 of the substrate 33 for use from the front side is provided.

  The protective cover 36 covers the front surface, outer peripheral surface, and inner peripheral surface of the coil substrate 33. That is, the protective cover 36 includes an annular front plate portion 38 that covers the front surface of the coil substrate 33 from the front side, a cylindrical outer peripheral wall portion 39 that covers the outer peripheral surface of the coil substrate 33 from the radially outer side, and a coil substrate. And a cylindrical inner peripheral wall portion 40 that covers the inner peripheral surface of 33 from the radially inner side. The outer peripheral wall portion 39 protrudes from the outer peripheral edge portion of the front plate portion 38 over the entire circumference and the inner peripheral wall portion 40 protrudes from the inner peripheral edge portion of the front plate portion 38 toward the rear over the entire periphery. Has been. As described above, the outer peripheral wall 39 and the inner peripheral wall 40 protrude rearward from the outer peripheral edge and the inner peripheral edge of the front plate portion 38, respectively, so that the protective cover 36 has an accommodation recess that opens rearward. When the coil substrate 33 enters the housing recess from the rear side, the front surface, outer peripheral surface, and inner peripheral surface of the coil substrate 33 are protected from the front, outer, and inner directions by the protective cover 36. It will be covered and protected. The outer peripheral wall 39 of the protective cover 36 extends beyond the coil substrate 33 to reach the outside of the outer peripheral surface of the stator. Specifically, the outer peripheral wall portion 39 of the protective cover 36 reaches the outer side of the outer peripheral surface of the stator insulating member 24 and overlaps the outer side of the outer peripheral surface by a predetermined length.

  Further, as shown in FIG. 8, a step portion 38a extending in the circumferential direction is formed in the middle portion of the front plate portion 38 of the protective cover 36 in the radial direction, and the front plate portion 38 and the inner peripheral region 38b are formed by the step portion 38a. The area 38c is divided into two areas. The inner peripheral area 38c of the front plate portion 38 is positioned one step behind the outer peripheral region 38b, and the front surface of the coil substrate 33 is in contact with the rear surface of the inner peripheral region 38c of the front plate portion 38. A predetermined gap is formed between the rear surface of the outer peripheral region 38 b of the portion 38 and the front surface of the coil substrate 33. Further, the inner peripheral surface of the protective cover 36 is the wall surface of the through hole 36a of the protective cover 36, but the step portion 38a is formed in the front plate portion 38, and the inner peripheral region 38c of the front plate portion 38 is the outer peripheral region. By being positioned one step rear as compared with 38b, the inner peripheral surface of the protective cover 36 has a shape that expands in a stepped manner toward the front side.

  The protective cover 36 is also positioned by the positioning pins 27 of the insulating member 24 of the stator. Further, the inner peripheral wall portion 40 of the protective cover 36 is inserted into the through hole 33a of the coil substrate 33, and the inner peripheral wall portion 40 of the protective cover 36 is positioned inside the through hole 33a of the coil substrate 33. However, an engagement claw 41 is formed at the rear end portion of the inner peripheral wall portion 40 of the protective cover 36 as shown in FIG. 9, and the engagement claw 41 is formed in the through hole 33 a of the coil substrate 33. Locking to the edge of the opening prevents the front cover from being removed from the coil substrate 33 of the protective cover 36. A plurality of engaging claws 41 are preferably provided at intervals in the circumferential direction. In this embodiment, a total of three engaging claws 41 are provided at intervals of 120 degrees. Further, a resin (not shown) is filled between the protective cover 36 and the coil substrate 33 as an insulating material, and the coil substrate 33 and the protective cover 36 are integrated by the resin. The resin is injected between the protective cover 36 and the coil substrate 33 in a liquid state. When the resin is solidified, the protective cover 36 and the coil substrate 33 are connected and integrated, and the protective cover 36 and the coil substrate 33 are integrated. The gap between is filled.

  A fan 50 is attached and fixed to the motor shaft 20, and the fan 50 rotates integrally with the motor shaft 20. The fan 50 is for cooling the brushless motor 4. When the fan 50 rotates, an air flow is generated in the housing, and the air flow becomes cooling air, mainly in the stator coil 25 of the brushless motor 4. Cool down. The fan 50 is disposed on the front side of the brushless motor 4, and the air flow in the housing is directed from the rear side to the front side.

  The fan 50 includes a wing portion 51 located on the outer peripheral portion, an attachment portion 52 to the motor shaft 20 located on the inner peripheral portion, and an intermediate portion 53 connecting the wing portion 51 and the attachment portion 52. The mounting portion 52 of the fan 50 is cylindrical, and the motor shaft 20 is inserted through the inside thereof. The mounting portion 52 of the fan 50 is located on the rear side of the wing portion 51, and the rear end surface of the mounting portion 52 is in contact with the front end surface of the rotor 21. The intermediate portion 53 of the fan 50 has a cylindrical shape that opens to the front side, and specifically has a tapered shape that increases in diameter toward the front side. The wing part 51 of the fan 50 extends radially outward from the front end of the intermediate part 53, and sends out air toward the radially outer side.

  The rear portion of the fan 50 is inserted through the through hole 33a of the coil substrate 33. The coil substrate 33 is covered with a protective cover 36, and the inner peripheral wall portion 40 of the protective cover 36 is located inside the through hole 33 a of the coil substrate 33. Therefore, the rear portion of the fan 50 is inserted through the through hole 36 a of the protective cover 36. Specifically, the intermediate portion 53 of the fan 50 is inserted through the through hole 36a of the protective cover 36 and is located inside the through hole 36a. Further, the wing portion 51 of the fan 50 is located on the front side of the front plate portion 38 of the protective cover 36. An exhaust-side vent 16 is formed at the position of the housing corresponding to the radially outer side of the wing 51 of the fan 50. More specifically, exhaust-side vent holes 16 are formed on the left and right side surfaces of the main cover 12 of the housing. Accordingly, air flows into the housing from the intake-side vent 15 on the rear end surface of the rear cover 11 along the axial direction (front-rear direction) of the motor shaft 20, and from both the left and right sides from the exhaust-side vent 16 of the main cover 12. Air is discharged toward

  Since the intermediate portion 53 of the fan 50 has a cylindrical shape that opens to the front side, a housing recess that opens to the front side is formed at the front center portion of the fan 50. Since the intermediate portion 53 of the fan 50 has a tapered cylindrical shape whose diameter increases toward the front side, the housing recess also has a tapered shape whose diameter increases toward the opening portion on the front side. The front bearing 17 that supports the front portion of the motor shaft 20 is disposed in the housing recess, and the front bearing 17 is located on the rear side of the front end face of the fan 50. The front bearing 17 is fitted from the rear side into a bearing holding portion 61 formed at the rear end portion of the inner case 60 fixed to the inside of the housing, and the bearing holding portion 13 enters the housing recess of the fan 50. The front bearing 17 is opposed to the front side of the front end surface of the mounting portion 52 of the fan 50 with a slight gap.

  An inner case 60 is housed and fixed inside the housing. The inner case 60 houses a drive transmission mechanism for transmitting the drive of the brushless motor 4 to the tip tool. The inner case 60 is regulated so as to abut against the stopper wall 12a projecting from the inner surface of the main cover 12 from the front side and not move further to the rear side. The outer peripheral portion of the rear end portion of the inner case 60 is in contact with the stopper wall 12a, and the inner peripheral portion of the rear end portion of the inner case 60 is not in contact with the stopper wall 12a and protrudes backward. . The bearing holding portion 61 of the inner case 60 is located on the rear side of the stopper wall 12a. Therefore, the front bearing 17 is located on the rear side of the stopper wall 12a and supports the front portion of the motor shaft 20. The motor shaft 20 protrudes from the front bearing 17 to the front by a predetermined length, and is connected to the spindle 64 at the protruding portion to transmit a driving force.

  In this manner, the stopper wall 12a and the inner peripheral portion of the rear end portion of the inner case 60 are located on the front side of the wing portion 51 of the fan 50, and these constitute the front fan casing. On the other hand, the front plate portion 38 of the protective cover 36 is located on the rear side of the wing portion 51 of the fan 50, and the front plate portion 38 constitutes a rear fan casing. As described above, the stopper wall 12 a, the inner case 60, and the front plate portion 38 of the protective cover 36 constitute a fan casing that covers the front and rear of the wing portion 51 of the fan 50.

  The drive transmission mechanism includes a speed reduction mechanism portion made up of a ring gear 62 and a planetary gear, an impact mechanism portion made up of a spindle 64 and a hammer 65, and a rotary impact force applied by the hammer 65, and a chuck hole 7 for holding a tip tool. And an anvil 66 having the same. The front end portion of the inner case 60 protrudes forward from the front cover 10 of the housing, and the anvil 66 protrudes forward from the inner case 60. By this drive transmission mechanism, the rotation of the brushless motor 4 is reduced to a striking rotation while being transmitted to the anvil 66, and a rotational force and a striking force are applied to the attached tip tool.

  A control circuit board 31 is provided inside the grip portion 2. The control circuit board 31 is for controlling the brushless motor 4, and a signal line 32 and a lead wire 35 are connected to the control circuit board 31. An output signal of the Hall element is sent to the control circuit board 31 via the signal line 32, and the rotation of the brushless motor 4 is controlled based on the output signal. In addition, drive power is sent from the control circuit board 31 to the stator coil 25 via the lead wire 35 and the coil substrate 33.

  In the electric tool configured as described above, since the coil substrate 33 is disposed on the front side of the stator coil 25, the lead wire 35 is routed to a place with a margin in the space away from the housing. Therefore, the lead wire 35 can be easily connected to the coil substrate 33. In addition, since the lead wire 35 is difficult to interfere with being separated from the housing, the front-rear length of the power tool can be made compact. In particular, the upper end portion of the grip portion 2 and the rear end portion of the head portion 3 do not bulge to the rear side due to the influence of the lead wire 35 being routed. In addition, it is easy to dispose screw bosses for screwing the main cover 12 of the housing. In addition, since the substrate extension 34 is provided at the lower end of the coil substrate 33 and the lead wire 35 is connected to the substrate extension 34, the lead wire 35 can be more easily connected and routed more easily. become.

  Further, since the fan 50 is located on the front side of the brushless motor 4, the hot air discharged from the exhaust-side vent 16 is far from the operator. Further, since the intake-side vent hole 15 is formed in the rear cover 11 constituting the rear end portion of the head portion 3, the air flow is smooth and the cooling efficiency is excellent. Further, since the protective cover 36 also functions as a fan casing, air is efficiently sent radially outward by the rotation of the fan 50 and discharged from the vent 16 on the exhaust side.

  On the other hand, since the sensor substrate 30 is disposed on the front side of the rear cover 11 and blocks between the intake-side vent 15 and the stator coil 25, even if foreign matter enters from the intake-side vent 15, the stator Foreign matter does not touch the coil 25 directly, and a short circuit in the stator coil 25 can be prevented. In addition, since the coil substrate 33 is disposed on the front side of the stator coil 25 and the protective cover 36 is further provided on the front side of the stator coil 25, the coil substrate 33 can be used even if foreign matter enters from the vent 16 on the exhaust side. In addition, a short circuit in the stator coil 25 can be prevented. In particular, since the protective cover 36 covers and protects not only the front surface of the coil substrate 33 but also the outer peripheral surface and the inner peripheral surface, the fan 50 is located near the coil substrate 33 and the coil substrate 33 is protected from the fan 50. Even if the rear part is inserted, the coil substrate 33 and the stator coil 25 are reliably protected. Further, since the resin is filled between the protective cover 36 and the coil substrate 33, that is, the front surface of the coil substrate 33 is resin-molded, the short circuit in the coil substrate 33 is further reduced. In addition to being prevented more reliably, the protective cover 36 can also be prevented from being displaced from the coil substrate 33 due to vibration.

  Further, the wing portion 51 of the fan 50 is located on the front side of the coil substrate 33, while the mounting portion 52 of the fan 50 is located on the rear side of the wing portion 51, and the through hole 36 a of the protective cover 36 together with the intermediate portion 53. The front bearing 17 is inserted into the accommodating recess formed by the intermediate portion 53. In this manner, by arranging the front bearing 17 in the housing recess of the fan 50, the brushless motor 4 and the drive transmission mechanism can be moved back and forth, and the front and rear length of the electric tool can be made even more compact. Can be In particular, since the intermediate portion 53 of the fan 50 has a taper shape whose diameter increases toward the front side, the front bearing 17 can be easily inserted and disposed, and the intermediate portion 53 of the fan 50 is inserted into the through hole 36a of the protective cover 36. Easy to insert into. In addition, since the through hole 36a of the protective cover 36 has a stepped diameter increasing toward the front side, interference between the protective cover 36 and the intermediate portion 53 of the fan 50 can be prevented, and the intermediate portion 53 of the fan 50 has a large diameter. It can be arranged on the rear side while converting.

  Further, by providing the sensor substrate 30 separately from the coil substrate 33, the degree of freedom in the shape of the coil substrate is increased, and the degree of freedom in design and arrangement is increased. Further, by separating the sensor substrate 30 from the coil substrate 33, the Hall element can be easily disposed at a position close to the motor shaft 20, and the rotation of the rotor 21 can be easily detected. Further, by separating the sensor substrate 30 from the coil substrate 33, it becomes easy to enlarge the through hole 33a of the coil substrate 33, and the rear portion of the fan 50 can be easily inserted and arranged, and the opening of the intermediate portion 53 is facilitated. The diameter can also be increased.

  In this embodiment, the protective cover 36 is provided on the front side of the coil substrate 33. However, without providing the protective cover 36, the front surface of the coil substrate 33 may be protected by simply molding it with resin. Good. Conversely, the resin filling between the coil substrate 33 and the protective cover 36 may be omitted, and only the protective cover 36 may be configured. As described above, the protection mode of the front surface of the coil substrate 33 by the insulating material may be various modes.

DESCRIPTION OF SYMBOLS 1 Battery mounting part 2 Grip part 3 Head part 4 Brushless motor 5 Trigger switch 6 Sleeve 7 Chuck hole 10 Front cover (housing)
11 Rear cover (housing)
12 Main cover (housing)
12a Stopper wall 13 Bearing holding portion 14 Rear bearing 15 Intake side vent 16 Exhaust side vent 17 Front bearing 20 Motor shaft 21 Rotor 23 Stator core 24 Insulating member 25 Stator coil 26 Positioning pin 27 Positioning pin 30 Sensor substrate 30a Through Hole 30b Ventilation hole 31 Control circuit board 32 Signal line 33 Coil board 33a Through hole 34 Substrate extension 35 Lead wire 36 Protective cover 36a Through hole 37 Extension cover part 38 Front plate part 38a Step part 38b Outer peripheral area 38c Inner peripheral area 39 outer peripheral wall portion 40 inner peripheral wall portion 41 engaging claw 50 fan 51 wing portion 52 mounting portion 53 intermediate portion 60 inner case 61 bearing holding portion 62 ring gear 63 planetary gear 64 spindle 65 hammer 66 anvil

Claims (4)

In a power tool provided with a brushless motor having an axis in the front-rear direction inside the housing, and a work tool driven by the brushless motor is disposed on the front side,
An electric tool, wherein a lead wire for supplying power to a stator coil of a brushless motor is connected and a coil substrate to which the stator coil is connected is disposed on the front side of the stator coil.   A fan for cooling the brushless motor is disposed on the front side of the coil substrate, a vent is formed in a portion of the housing facing the outer periphery of the fan, and the front surface of the coil substrate is protected by an insulating material. Item 1. The electric tool according to Item 1. A fan for cooling the brushless motor is provided, the fan including a wing portion located on the outer peripheral portion, an attachment portion to the motor shaft located on the inner peripheral portion, and an intermediate portion connecting the wing portion and the attachment portion. With
A through hole is formed in the center of the coil substrate,
The fan wing is located on the front side of the coil substrate, the fan mounting portion is located on the rear side of the wing portion, and the rear of the fan is inserted through the through hole of the coil substrate,
The electric tool according to claim 1 or 2, wherein the intermediate portion is a cylindrical shape opened to the front side, and is arranged so that at least a rear portion of a bearing supporting the front portion of the motor shaft enters inside the intermediate portion.   The electric power tool according to any one of claims 1 to 3, wherein a sensor board having a Hall element for detecting rotation of a rotor of the brushless motor is arranged on the rear side of the brushless motor separately from the coil board. .

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