JP4986258B2 - Electric tool - Google Patents

Description

  The present invention relates to an electric tool using a brushless motor, and more particularly to a structure of an electric tool with improved cooling effect and dustproof effect for a brushless motor housed in a motor housing portion.

  In general, a brushless motor (DC motor) can be miniaturized, and electrical connection using a brush and a commutator is not required for a rotor attached to a rotating shaft, so that a long life is possible. However, when a brushless motor is driven, a relatively large power loss occurs as heat, and the high output of the motor and normal operation may be hindered by the influence of heat. Most of the power loss is a copper loss caused by a current flowing through the stator coil and an iron loss caused in the stator core material due to a change in magnetic flux density. In particular, the loss of the stator portion is a large heat source. For this reason, cooling structures for various stators have been proposed in conventional brushless motors. For example, as a conventional stator cooling structure, as disclosed in Patent Document 1 below, an opening for sucking outside air into the motor housing, and an opening for discharging cooling air inside the housing to the outside of the housing, Are provided in the housing so as to be spaced apart from each other in the direction of the rotation axis across the stator, and air is introduced into the housing by a fan integrally attached to the rotor, and in particular, by flowing cooling air between the stator coils A structure for directly cooling the stator coil portion has been proposed.

  Further, in the brushless motor, the output transistor that constitutes the switching element of the inverter circuit board (motor drive circuit board) supplies a large current drive signal to the stator coil, so the amount of heat generation increases and cooling measures are required. . As a cooling structure for an inverter circuit board, a structure in which an inverter circuit board is arranged together with a stator portion of a motor on a cooling gas flow path in a motor housing has been proposed as disclosed in Patent Document 2 below. .

JP 2004-274800 A JP 2005-102370 A

  The brushless motor eliminates the need for electrical connection using a brush and commutator to the rotor of the motor, so that it can have a long service life and can prevent dust from entering the motor. Easy to achieve. For this reason, it is thought that a brushless motor is suitable as a drive source of a portable electric tool using a DC power source.

  The inventor of the present application has studied the application of a brushless motor to a drive source of a portable electric tool such as an impact driver. In an electric tool used in an air working environment in which wood powder or metal powder is mixed, The air gap between the stator and rotor of the motor is clogged with iron powder or wood powder, causing a lock phenomenon in the motor. As a result, an excessive current flows through the coil, causing failure such as coil burning. Therefore, dust-proof measures were required.

  As a simple dust-proof structure that prevents dust from entering the motor, it is conceivable that the entire motor housing is sealed. However, if the entire motor is simply sealed, the cooling air will inevitably flow, so the cooling effect will be impaired, and the winding temperature will rise abnormally even during normal operation, resulting in coil burnout. Problems that cause failures such as the above occur.

  Further, when the brushless motor has a sealed dustproof structure, it is necessary to consider a wiring structure for supplying power or a control signal from the outside to the stator coil of the brushless motor.

  Accordingly, a main object of the present invention is to provide an electric tool having a brushless motor having a cooling structure having a cooling structure having an excellent cooling effect as well as a dust-proof structure of a motor unit for preventing dust from being sucked. .

  Another object of the present invention is to provide a wiring structure for supplying drive power to a stator coil of a brushless motor in a sealed dustproof structure of a brushless motor.

  Of the inventions disclosed in the present application, typical features will be described as follows.

One feature of the present invention is that a housing portion provided with an air inlet, a substantially cylindrical stator having an outer peripheral portion and an inner peripheral portion around which a stator coil is wound and extending in the rotation axis direction, and an inner portion of the stator. A brushless motor housed in the housing part, a substrate connected to the stator coil of the brushless motor, and a housing part housed in the housing and mounted on the rotating shaft The brushless motor includes a protrusion provided in the stator to insulate the stator and the stator coil, and projecting from the end of the stator in the rotation axis direction. comprising an insulating member having the substrate is near that is fixed to the projecting portion of the insulating member so as to cover an end portion of the stator of the intake port side .

Another feature of the present invention includes a discharge port for discharging the cooling gas sucked into the housing portion from the intake port to the outside of the housing portion, and the discharge port is separated from the intake port, It is formed in the housing part .

Another feature of the present invention resides in that an inverter circuit board including a plurality of switching elements for supplying current to the stator coil of the brushless motor is provided, and the inverter circuit board and the board are provided separately .

Another feature of the present invention is that the substrate includes an inverter circuit substrate including a plurality of switching elements for supplying current to the stator coil of the brushless motor, and the inverter circuit substrate is provided in the housing portion from the intake port. It is arranged in the flow path of the cooling gas sucked into the air.

Another feature of the present invention resides in that the plurality of switching elements are arranged to lie on the substrate.

  According to the above-described electric power tool of the present invention, the pair of holder members disposed inside the motor housing portion form a sealed structure for the motor (rotor) in cooperation with the stator of the motor, and the outer periphery of the stator. Since the space is formed in the portion and the cooling air is allowed to flow, the dustproof function of the motor can be improved and the cooling effect of the motor can be further improved.

  In addition, when one of the holder members is formed of a circuit board, it becomes easy to take out the wiring of the stator coil of the brushless motor.

  The above and other objects of the present invention, and the above and other features of the present invention will become more apparent from the following description of the present specification and the accompanying drawings.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof will be omitted.

[First Embodiment]
FIG. 1 shows a sectional view (front view) of the entire tool according to the first embodiment in which the electric tool of the present invention is applied to a cordless type impact driver. First, the configuration of the entire tool will be described with reference to FIG. The impact driver 50 according to the embodiment of the present invention extends from one end (the right end in the drawing) to the other end (the left end in the drawing) along the same direction as the rotation shaft 11 of the brushless motor 3 to be described later. A motor housing portion 50a of a synthetic resin material for housing the motor 3, a power transmission housing portion 50b for housing the power transmission mechanism portion 4 formed continuously at the other end of the motor housing portion 50a, and a motor housing portion 50a and a handle body portion 50c hanging from the power transmission housing portion 50b. The tip portion of the power transmission housing portion 50b protrudes from the end of the anvil 10, and the anvil square hole portion 10a has a tip tool. For example, a driver bit (not shown) is detachably inserted and can be fixed by the mounting member 10b. A bolt tightening bit can also be attached to the anvil square hole portion 10a as another tip tool.

  The motor housing portion 50a has a cylindrical shape, and a brushless DC motor 3 serving as a driving source is accommodated or mounted in the inner peripheral portion thereof. A structure for mounting the brushless motor 3 to the motor housing 50a will be described later.

  A power transmission mechanism portion 4 for transmitting the rotational force of the motor 3 to the anvil 10 as a rotational striking force is accommodated in the power transmission housing portion 50b continuous with the motor housing portion 50a. The power transmission mechanism unit 4 includes a speed reduction mechanism unit composed of a planetary gear 6 and a ring gear 7, a spindle 8 and a hammer 9 that is slidable on the spindle 8 and is provided with a striking force by a spring 5. And an anvil 10 that is provided with a rotating impact force by the hammer 9 and can hold a tip tool (not shown) as described above.

  A battery pack case 1 serving as a driving power source for the motor 3 is detachably attached to the handle housing portion 50c at the lower end portion of the handle housing portion 50c. The battery pack case 1 accommodates a battery pack body made of a lithium ion secondary battery, a nickel-cadmium secondary battery, or the like (not shown), and most of the battery pack body is inserted and accommodated in the handle housing portion 50c. The battery pack case 1 is electrically connected to the motor drive circuit device 2 via a trigger switch 50d provided in a part of the handle housing portion 50c. The motor drive circuit device 2 is electrically connected to a stator coil 12a (for example, a star-connected three-phase coil) of a brushless motor 3 described later, and rotationally drives the rotor 13 of the motor 3.

  The motor drive circuit device 2 includes an inverter circuit (not shown) including a known bridge circuit for energizing a drive current to the stator coil 12a of the brushless motor 3, and further includes a control circuit including a CPU and the like for controlling the inverter circuit. It has. In particular, the inverter circuit constituting the motor drive circuit device 2 requires a large drive current to be passed through the stator coil 12a, so that it has a large capacity such as an IGBT (insulated gate bipolar transistor) that operates as a switching element. Output transistors must be used. For this reason, the power loss of the output transistor becomes large, and heat generation becomes a problem. Therefore, a heat dissipation structure for improving the cooling effect is considered in the output transistor of the motor drive circuit device 2. In the present embodiment, the stator coil wiring and the inverter circuit are integrated in the motor drive circuit device 2, but in other embodiments described later, the inverter circuit board and the stator coil wiring substrate are specially separated from the motor drive circuit device 2. And mounted in the motor housing portion 50a.

  According to the impact driver 50 configured as described above, when the operator pulls the trigger switch 50d while holding the handle housing portion 50c, the trigger switch 50d is turned on, and the operation of the impact driver 50 can be started.

  During the screw tightening operation, the rotational force of the motor 3 transmitted from the rotary shaft 11 is decelerated by the planetary gear 6 and the ring gear 7, and the rotational force is transmitted to the spindle 8, and the anvil 10 (tip tool) during the screw tightening. When a load torque exceeding a predetermined value is applied, the hammer 9 converts the rotational force into a striking force by the action of the spring 5. Thereby, the hammer 9 can apply a rotational striking force to the tip tool mounted on the anvil 10 and tighten the screw.

  Next, the mounting structure of the brushless motor 3 to the motor housing portion 50a according to the present invention will be described with reference to FIGS. 2, 3, and 4. FIG. 2 is an enlarged cross-sectional view of the brushless motor unit 3 of the electric tool shown in FIG. 1, FIG. 3 is a cross-sectional structural view taken along line AA of the brushless motor unit 3 shown in FIG. 2, and FIG. 4 is a brushless motor shown in FIG. Sectional structural drawing which follows the BB line of the part 3 is shown, respectively.

  As shown in FIG. 3, the brushless motor 3 includes a stator 12 having a cylindrical outer shape, and four permanent magnet members 13 c that are disposed in the inner peripheral portion 12 b of the stator 12 and are embedded in the rotation axis direction. And a rotor 13. A slot 12f extending in the direction of the rotation axis is provided between the inner peripheral portion 12b of the stator 12 and the outer peripheral portion 12c, and the stator coil 12a is wound around the stator core in the slot 12f. The stator coil 12a forms a star-connected three-phase coil, and six IGBTs (output transistors) for supplying a large drive current to the stator coil 12a are attached to the inverter circuit constituting the motor drive circuit device 2. It has been.

  As shown in FIG. 2, both end portions 12 d and 12 e in the rotation axis direction of the stator 12 are sandwiched by the sandwiching portions 14 a of the pair of holder members (support members) 14, and the inner peripheral portion 50 f (FIG. 3). Reference) is fixed. Further, both end portions 12 d and 12 e of the stator 12 and both end portions 13 a and 13 b in the rotation axis direction of the rotor 13 are surrounded by a partition wall portion 14 b of the pair of holder members 14. The sandwiching portion 14a and the partition wall portion 14b of the pair of holder members 14 together with the stator 12 form a sealed structure surrounding the rotor 13 installed inside the inner peripheral portion 12b of the stator 12, and the motor 3 is placed in the motor housing portion 50a. Partition or isolate the installation space. This prevents dust from entering the rotor 13 of the motor 3.

  A pair of bearing members (for example, ball bearings) 11 a that support the rotating shaft 11 of the rotor 13 are installed on the pair of holder members 14. In other embodiments to be described later, the pair of bearing portions do not necessarily have to be installed on the pair of holder members 14, and one of the pair of bearing members 11 a may be formed on another member of the power transmission mechanism portion 4. .

  Both or one of the pair of holder members 14 can be integrally formed as a rib member together with the motor housing portion 50a using a synthetic resin material. The pair of holder members 14 may be formed of a synthetic resin material that is a separate member from the motor housing portion 50a, and may be fixed to the motor housing portion 50a. Further, the pair of holder members 14 may be formed of a metal material different from the motor housing portion 50a and fixed to the motor housing portion 50a by fitting or the like. When a metal material is used for the holder member 14, the holder member 14 functions as a heat radiating fin of the stator 12, so that the heat radiating effect of the stator 12 can be improved and the mechanical strength of the holder member 14 is enhanced. Wear of the support portion of the bearing member (bearing) 11a can be reduced, and the accuracy of the support position of the motor rotating shaft 11 can be improved. The holder member 14 is made of a material different from the member of the motor housing portion 50a, thereby improving the assembly property of the holder member to the motor housing portion, and the position and size of a through hole serving as a cooling air flow passage. The degree of freedom in designing the holder member can be improved. In the first embodiment shown in FIG. 2, of the pair of holder members 14, one holder member 14 disposed on the right hand side is integrally formed with the motor housing portion 50a as shown in FIGS. It is comprised by the rib member made. The holding portion 14a of the other holder member 14 arranged on the left hand side is formed integrally with the motor housing portion 50a, and the partition wall portion 14b is different from the motor housing portion 50a constituting the power transmission mechanism portion 4. It is formed by a member.

  As will be apparent from this embodiment and other embodiments described later, the term “clamping portion (14a)” of the pair of holder members 14 means that the clamping portion forms an enclosed or sealed structure together with the outer peripheral surface of the stator. Means a member extending along the rotational axis direction, and is not limited to a member that is completely in contact with or connected to the end portion of the stator 12, and dust substantially enters the inner peripheral portion of the stator from the end portion of the stator 12. It may be a member extending in the direction of the rotation axis with a gap that does not occur. Moreover, you may comprise the clamping part with a single member or multiple members. On the other hand, the term “partition wall part (14b) of the pair of holder members 14 means that the partition wall part intersects with the clamping part (14a) so as to cover the ends of the stator 12 and the rotor 13 (for example, in the direction of the rotation axis). This means a member that extends in the vertical direction) and has an enclosing or shielding effect in which dust does not substantially enter the stator inner peripheral portion from the end portion side of the stator 12 together with the sandwiching portion. The partition wall portion can be composed of a single member or a plurality of members in the same manner as the sandwiching portion.

  4 and 5, the housing member 50 including the motor housing portion 50a, the power transmission housing portion 50b, and the handle housing portion 50c is a cross section that is divided into two by a vertical plane that crosses the rotation axis center of the motor 3. A pair of semi-circular housing members 50 (see FIG. 4) is prepared, and the rotor rotating shaft 11 and the stator 12 of the motor 3 are assembled in advance in one housing member 50 as shown in FIG. Thereafter, a method is adopted in which the other of the pair of housing members 50 is overlapped and the pair of housing members are coupled by screwing or the like as shown in FIG.

  As shown in FIG. 3, a space 16 serving as a flow path for cooling air (cooling gas) is formed between the inner peripheral portion 50f of the motor housing portion 50a and the outer peripheral portion 12c of the stator 12. In addition, as shown in FIG. 2, an intake port 17 is formed in the end wall portion 50e on one end side of the motor housing portion 50a for sucking cooling air from outside air. Further, a cooling fan 15 for sucking outside air from the intake port 17 is provided between the end wall portion 50e of the motor housing portion 50a and the one holder member 14 on the right side. The cooling fan 15 is attached to the end of the rotating shaft 11 that protrudes through the partition wall 14 b of the right holder member 14. The partition 14b of the right holder member 14 is provided with a through hole (vent hole) 19 for flowing cooling air. As shown in FIG. 4, the through holes 19 are formed at two opposing positions on the outer peripheral portion of the holder member (rib member) 14 b. The size and installation position of the through hole 19 can be determined in consideration of the workability to the holder member 14. It should be noted that the through hole 19 is formed so as not to penetrate the partition wall 14b of the holder member 14 that surrounds or seals the inside of the motor. On the other hand, in the vicinity of the outer peripheral portion 12c of the stator 12, a plurality of exhaust ports 18 for discharging cooling air to the outside air are provided in the motor housing portion 50a. The positions of the cooling air intake port 17 and the exhaust port 18 are formed in the motor housing portion 50 a so as to be separated from each other along the rotation shaft 11 so as to sandwich the space portion 16 of the outer peripheral portion of the stator 12. The exhaust port 18 may be formed in the power transmission housing part 50b adjacent to the motor housing part 50a.

  With the above configuration, as shown in FIGS. 2 and 3, the intake port 17, the through hole 19, the space portion 16, and the exhaust port 18 form a flow path for cooling air (cooling gas) 20. When the motor 3 is operated, the cooling fan 15 attached to the rotating shaft 11 rotates, and the cooling air 20 is sucked into the motor housing portion 50a from the intake port 17. The sucked cooling air 20 flows through the through hole 19 provided in the motor housing portion 50a and flows into the space 16 between the outer peripheral portion 12c of the stator 12 of the motor 3 and the inner peripheral portion 50f of the motor housing portion 50a. In this state, both end portions 12d and 12e of the stator 12 in the rotation axis direction and both end portions 13a and 13b of the rotor 13 in the rotation axis direction are sandwiched by the holder member (rib member) 14 by the holder member (rib member) 14. As described above, since the motor 3 is fixed to the motor housing portion 50a, the motor 3 has a sealed structure (enclosed structure) partitioned or isolated from other space portions. Therefore, compared with the structure of the conventional brushless motor, it becomes a structure where outside air enters the inside of the motor 3 very little, and it can be made a structure where dust hardly enters. And since the cooling air 20 which flowed into the space part 16 flows through the outer peripheral part 12c of the stator 12, and is discharged to outside air while cooling the stator 12, the heat dissipation effect of the stator 12 can be improved. Therefore, according to this invention, the electric tool which improved the dustproof performance and cooling performance of the motor can be provided.

[Second Embodiment]
In the first embodiment, the cooling fan 15 is disposed in the vicinity of the end wall portion 50e of the motor housing portion 50a (in the vicinity of the intake port 17). However, as in the second embodiment shown in FIG. 15 may be attached to the rotating shaft 11 between the power transmission mechanism and the left holder member 14. In this case, the exhaust port 18 provided in the housing part 50 a is disposed in the vicinity of the outer peripheral part of the cooling fan 15. As in the second embodiment shown in FIG. 6, if the cooling air flows through the space 16 surrounding the outer peripheral portion 12c of the stator 12 and the interior of the motor 3 is sealed, the position of the cooling fan 15 and the cooling air The position of the opening hole 17 or 18 of the housing portion 50a for sucking or discharging 20 is not particularly limited. With such a configuration, the same cooling effect and sealing effect as those of the first embodiment can be obtained.

[Third Embodiment]
FIG. 7 shows a third embodiment. In particular, the motor drive circuit device 2 (see FIG. 1) includes an inverter circuit (not shown) including a well-known bridge circuit for supplying a drive current to the stator coil 12a of the brushless motor 3 in addition to a control circuit including a CPU and the like. ) Is included. In the inverter circuit, since it is necessary to pass a large drive current through the stator coil 12a, a large-capacity output transistor such as an IGBT (insulated gate bipolar transistor) must be used. For this reason, the power loss of the output transistor becomes large, and heat generation becomes a problem. Therefore, a heat dissipation structure for improving the cooling effect is considered in the output transistor of the motor drive circuit device 2. According to the third embodiment shown in FIG. 7, the inverter circuit board 22 is separated from the motor drive circuit device 2 of the handle housing portion 50c shown in FIG. It is installed in the cooling air flow passage. The inverter circuit board 22 is fixed to the inner peripheral part of the motor housing part 50a, and for example, six output transistors (IGBTs) 21 are mounted thereon. These output transistors 21 generate heat during driving of the motor 3, but are forcedly cooled by cooling air, so that highly efficient output power can be obtained.

[Fourth Embodiment]
FIG. 8 shows a fourth embodiment. As in the third embodiment shown in FIG. 7, the inverter circuit board 22 is installed in the cooling air flow passage in the motor housing portion 50c. 7 is different from the third embodiment of FIG. 7 in that the output transistor 21 of the inverter circuit board 22 is mounted so as to be in contact with a heat radiating portion (not shown) of the circuit board 22. According to this embodiment, the heat dissipation effect can be improved as in the embodiment shown in FIG.

[Fifth Embodiment]
9 to 13 show a fifth embodiment according to the present invention. FIG. 9 is an overall configuration diagram, and FIG. 10 is an enlarged cross-sectional view of the motor housing portion of the power tool shown in FIG. 11 is a sectional view taken along line AA of the power tool shown in FIG. 9, FIG. 12 is a sectional view taken along line BB of the power tool shown in FIG. 9, and FIG. 13 is shown in FIG. Sectional drawing which follows the CC line of a power tool is shown, respectively. Constituent members similar to those of the above-described embodiment are denoted by the same reference numerals and description thereof is omitted. Hereinafter, the mounting structure of the brushless motor 3 to the motor housing 50a will be described in detail with reference to FIGS.

  Similar to the above-described embodiment, a slot 12f extending in the rotation axis direction is provided between the inner peripheral portion 12b of the stator 12 and the outer peripheral portion 12c. In particular, in the present embodiment, the stator 12 is inserted into both ends 12d and 12e of the stator 12 along the shape of the slot 12f, and a pair of insulator members 14d and 14e that are in contact with each other at the central portion 12g in the rotation axis direction of the stator 12 are provided. Have. The pair of insulator members 14d and 14e are made of an insulating material, and the stator coil 12a is wound around the insulator members 14d and 14e, so that the electrical insulation between the core of the stator 12 and the stator coil 12a can be made more complete. it can. The pair of insulator members 14 d and 14 e have cylindrical protrusions 14 d 1 and 14 e 1 that protrude so as to cover the outer periphery of the rotor 13 at both ends 12 d and 12 e of the stator 12. In particular, the insulator member 14e inserted from the right-hand end of the stator 12 has an outer diameter cylindrical protrusion 14e2. Further, a clamping portion fixing member (rib member) 30 formed integrally with the motor housing portion 50a is disposed on the outer peripheral portion of the outer diameter cylindrical protruding portion 14e2, and the stator 12 is fixed to the motor housing portion 50a. . The outer peripheral surface of the outer cylindrical protrusion 14e2 is preferably disposed so as to be completely in contact with the inner peripheral surface of the holding member fixing member 30, but the outer peripheral surface of the outer cylindrical protrusion 14e2 There may be a very small gap between the inner peripheral surface of the clamping unit fixing member 30 so that dust does not enter. Thus, the clamping part 14a of the holder member 14 in this embodiment is comprised by the composite member of the clamping part fixing member 30 and the cylindrical protrusion part 14e2.

  Furthermore, the outer peripheral edge of the circular stator coil wiring board 31 is fitted or connected to the cylindrical protrusion 14e2 of the insulator member 14e. The stator coil wiring board 31 is composed of, for example, a wiring board in which a conductive layer such as a copper foil or a conductive wire is attached or attached to a synthetic resin material board. As shown in FIG. 12 and FIG. Furthermore, it has the conductive layer or conducting wire (connection part) 31a-31i which penetrates the surface by the side of the cooling fan 15 more. Further, a central portion of the circular stator coil wiring board 31 has a bearing through hole 31x for allowing the rotary shaft 11 to pass therethrough.

  In the present embodiment, in particular, the wiring of the stator coil 12a is drawn out to the stator coil wiring board 31 along the rotation axis direction, and after being wired by the stator coil wiring board 31, it is electrically connected to the motor drive circuit device 2. For example, when the brushless motor 3 is a general three-phase motor, the terminals of the three stator coils 12a driven in three phases are electrically connected to the connection portions 31a to 31i of the stator coil wiring board 31 by soldering or the like. Star connection (Y connection) is performed on the coil wiring board 31. A wiring terminal that is star-connected (Y-connected) on the stator coil wiring board 31 is electrically connected to a drive output transistor (not shown) configured by an IGBT or the like of the motor drive circuit device 2 through a conductive wire 31k.

  The outer peripheral edge of the circular stator coil wiring board 31 is attached in close contact with the inner peripheral part of the outer cylindrical protrusion 14e2 of the insulator member 14e. The inner peripheral edge portion of the hole 31x is in contact with a bearing holding portion 32 that supports the bearing 11a attached to the rotary shaft 11, and the bearing penetration hole 31x of the stator coil wiring board 31 is covered with the bearing holding portion 32. It is sealed from the outside on the cooling fan 15 side. That is, according to the present embodiment, the partition wall portion 14 b of the holder member 14 is configured by the stator coil wiring board 31 and the bearing holding portion 32.

  From the surface opposite to the stator 12 of the stator coil wiring board 31, a conductor 31k corresponding to the input terminal of the star-connected three-phase coil is wired, and the terminal for the neutral point of the star-connected three-phase coil is The stator coil wiring board 31 is electrically connected in common.

  According to the fifth embodiment, the stator coil 12a and the rotor 13 provided in the stator 12 of the brushless motor 3 can be easily used by using the stator coil wiring board 31 and the bearing holding portion 32 as the partition wall portion (14b). Can be sealed. Further, the stator coil wiring board 31 allows the stator coil 12a to be easily electrically wired from the sealed space to the outside.

[Sixth Embodiment]
In the fifth embodiment, the outer cylindrical protrusion 14e2 of the insulator member 14e extends in the direction of the rotating shaft 11 so as to surround or seal the stator coil 12a of the stator 12. 14, the stator 12 and the stator coil are wound after the winding operation of the stator coil 12 a by using a cylindrical protrusion 14 e 3 formed of a synthetic resin or the like separately from the insulator member 14 e as shown in FIG. A cylindrical protrusion 14e3 may be sandwiched between the wiring substrate 31 and enclosed or sealed. The clamping part 14a of the holder member 14 in the sixth embodiment is composed of a composite member of the clamping part fixing member 30 and the cylindrical protruding part 14e3, as in the fifth embodiment.

[Seventh Embodiment]
FIG. 15 shows a seventh embodiment. The outer peripheral edge portion of the stator coil wiring board 31 is fitted into a groove 30a provided in the inner peripheral portion of the cylindrical fixing member (rib member) 30, and the end portions of the stator coil 12a and the rotor 13 are hermetically enclosed. It is a thing.

[Eighth Embodiment]
FIG. 16 shows an eighth embodiment. About the mounting structure to the motor housing part 50a of the brushless motor 3, it is the structure similar to 5th Embodiment shown in FIG. On the other hand, the inverter circuit board 22 is separated from the motor drive circuit device 2 disposed in the handle housing portion 50c, and the cooling air in the motor housing portion 50a is separated as in the third embodiment shown in FIG. It is installed in the flow path of. As in the third embodiment shown in FIG. 7, the inverter circuit board 22 has six output transistors (IGBTs) 21 mounted thereon. These output transistors 21 generate heat during driving of the motor 3, but are forcedly cooled by the cooling air in the motor housing portion 50a, so that highly efficient output power can be obtained.

  As will be apparent from the above description of the embodiment, according to the electric tool of the present invention, the rib member disposed in the motor housing portion, the insulator member used in the slot of the stator, the stator coil wiring board, etc. By including a pair of holder members, a sealed structure for the motor (rotor) is formed in cooperation with the stator of the motor, and a space is formed in the outer peripheral portion of the stator to flow cooling air, so that the dust-proof function of the motor is achieved. The cooling effect of the motor can be further improved.

  In the above embodiment, the battery pack (secondary battery) 1 is used as the power source of the motor drive circuit device 2, but the motor drive circuit is connected via a converter circuit (not shown) that rectifies commercial power for general household use. The device may be powered.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. It is.

1 is an overall cross-sectional view of a power tool according to a first embodiment of the present invention. The expanded sectional view of the motor housing part of the electric tool shown in FIG. Sectional drawing which follows the AA line of the enlarged view shown in FIG. Sectional drawing which follows the BB line of the enlarged view shown in FIG. The fragmentary sectional view of the motor housing member of the electric tool shown in FIG. The expanded sectional view of the motor housing part of the electric tool which concerns on the 2nd Embodiment of this invention. The expanded sectional view of the motor housing part of the electric tool which concerns on the 3rd Embodiment of this invention. The expanded sectional view of the motor housing part of the electric tool which concerns on the 4th Embodiment of this invention. The whole sectional view of the electric tool concerning a 5th embodiment of the present invention. The expanded sectional view of the motor housing part of the electric tool shown in FIG. Sectional drawing which follows the AA line of the enlarged view shown in FIG. Sectional drawing which follows the BB line of the enlarged view shown in FIG. Sectional drawing which follows the CC line of the enlarged view shown in FIG. The expanded sectional view of the motor housing part of the electric tool which concerns on the 6th Embodiment of this invention. The expanded sectional view of the motor housing part of the electric tool which concerns on the 7th Embodiment of this invention. The whole electric tool sectional view concerning an 8th embodiment of the present invention.

Explanation of symbols

1: Battery pack case 2: Motor drive circuit device 3: Brushless motor 4: Power transmission mechanism 5: Spring 6: Planetary gear 7: Ring gear 8: Spindle 9: Hammer 10: Anvil 10a: Anvil square hole 10b: Tip Tool mounting member 11: Rotating shaft 11a: Bearing member 12: Stator 12a: Stator coil 12b: Stator inner periphery 12c: Stator outer periphery 12d: Stator one end 12e: Stator other end 12f: Stator slot 13 : Rotor 13a: One end portion of rotor 13b: Other end portion of rotor 13c: Permanent magnet member 14: Holder member (rib member) 14a: Clamping portion 14b: Partition portion 14d: Insulator member 14d1: Cylindrical protruding portion 14e: Insulator member 14e1, 14e2, 14e3: Cylindrical protrusion 15: Cooling fan 16: Space 17: Inlet 18: Exhaust 19: Through hole (vent) 20: Cooling air (cooling gas) 21: Output transistor 22: Inverter circuit board 30: Holding part fixing member 30a: Groove 31: Stator coil Wiring boards 31a to 31i: Connection portion 31k: Conductive wire 31x: Bearing through hole 32: Bearing holding member 50: Electric tool (impact driver) 50a: Motor housing portion 50b: Power transmission housing portion 50c: Handle housing portion 50d: Trigger switch 50e: End wall portion 50f of motor housing: Inner peripheral portion of motor housing portion

Claims (5)

A housing part provided with an air inlet;
A substantially cylindrical stator having an outer peripheral portion and an inner peripheral portion around which a stator coil is wound and extending in the direction of the rotation axis, and a rotor disposed substantially concentrically inside the stator, and accommodated in the housing portion A brushless motor to be
A substrate connected to the stator coil of the brushless motor;
In a power tool comprising a cooling fan housed in the housing part and attached to the rotating shaft,
The brushless motor includes an insulating member that is provided on the stator, insulates the stator from the stator coil, and has a protruding portion that protrudes from the end of the stator in the rotation axis direction.
The electric power tool, wherein the substrate is fixed to the projecting portion of the insulating member so as to cover an end portion of the stator on the inlet side. A cooling gas sucked into the housing part from the air inlet is provided with a discharge port for discharging the gas out of the housing part;
The electric power tool according to claim 1, wherein the discharge port is formed in the housing portion so as to be separated from the intake port. Comprising an inverter circuit board comprising a plurality of switching elements for energizing the stator coil of the brushless motor;
The electric tool according to claim 1 or 2, wherein the inverter circuit board and the board are provided separately. The board is composed of an inverter circuit board including a plurality of switching elements for energizing the stator coil of the brushless motor,
The electric power tool according to claim 2, wherein the inverter circuit board is disposed in a flow path of a cooling gas sucked into the housing portion from the intake port. The power tool according to claim 3 or 4, wherein the plurality of switching elements are arranged so as to lie on the substrate.

Images