JP2014061557A - Electric tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric tool which achieves excellent waterproof/dustproof functions even through a motor with a brush is adopted as a motor.SOLUTION: An electric tool includes: a housing 2 which forms a motor housing space 2d having a closed chamber structure and used for housing a motor 4; a fan 19 which forms airflow in the motor housing space 2d; and a cooling plate 30 which is disposed in a passage of the airflow formed by the fan 19 and radiates heat in the motor housing space 2d to the exterior. The structure efficiently radiates the heat in the motor housing space to the exterior.

Description

  The present invention relates to an electric power tool such as an impact driver having a motor as a rotation drive unit.

  An electric power tool such as an impact driver having a motor as a rotational drive unit requires a cooling structure for cooling the motor that becomes high temperature during operation, and air is introduced by providing an air supply / exhaust hole near the motor of the housing. It is common. On the other hand, when air is taken into the housing from the outside, dust and water droplets in the air are also taken into the housing, and it is necessary to take measures against dust and water droplets. In view of this, a technique has been proposed in which a brushless motor is employed as a motor and coating with a resin such as silicon so as to cover a circuit board for driving the brushless motor, thereby preventing a short circuit due to dust or water droplets (for example, , See Patent Document 1). Moreover, the motor etc. are cooled with the air taken in from the outside.

JP 2010-264534 A

  However, when a motor with a brush is used as the motor, there is a problem that the electrode of the brush portion cannot be resin-coated and a short circuit due to dust or water droplets cannot be prevented.

  The present invention has been made in view of the above situation, and provides an electric tool capable of solving the above-described problems and realizing an excellent waterproof / dustproof function while improving (maintaining) the cooling performance of the motor. The purpose is to do.

The power tool of the present invention is a power tool including a motor, and includes a housing that forms a motor housing space in which the motor is housed, and a heat radiating unit that radiates heat inside the motor housing space to the outside. It is characterized by that.
Furthermore, in the electric power tool of the present invention, the power tool includes air flow forming means for forming an air flow in the motor housing space, and the heat radiating means is provided in an air flow passage formed by the air flow forming means. It may be arranged.
Furthermore, in the electric power tool of the present invention, the air flow forming means is a fan provided in the rotor of the motor, and the air flow that circulates at least one of the inner peripheral side and the outer peripheral side of the stator of the motor. You may make it form.
Furthermore, in the electric tool of the present invention, the motor housing space may be a closed room structure.
Furthermore, in the electric tool of the present invention, the heat radiating means may be arranged outside the stator of the motor.
Further, in the electric tool of the present invention, the motor is a motor with a brush, and the air flow forming means is a fan provided on a rotor of the brushed motor, and the inner peripheral side of the magnet of the brushed motor And an air flow that circulates through at least one of the outer periphery of the yoke of the brush motor.
Furthermore, in the electric tool of the present invention, the heat radiating means may be a cooling plate fitted in an opening formed in the housing.
Furthermore, in the electric tool of the present invention, a part of the cooling plate may be brought into contact with the stator of the motor.
Furthermore, in the electric power tool of the present invention, the housing may be configured by a plurality of members, and the cooling plate may be sandwiched and held by the plurality of members configuring the housing.
Furthermore, in the electric power tool of the present invention, the housing includes a body part that forms the motor housing space, and a handle part that is connected to the body part so as to form a substantially T shape in a side view, The cooling plate may be provided on the opposite side of the body portion where the handle portion is connected.
Furthermore, in the electric tool of the present invention, the motor is a motor with a brush, and the housing that forms the motor housing space is formed with an opening through which a lead wire of a power source applied to the brush portion of the motor is passed. In addition, a closing material for sealing a gap between the opening through which the lead wire passes and the lead wire may be provided.
Furthermore, in the electric tool of the present invention, the heat radiating means may be a member having higher thermal conductivity than the housing.

  According to the present invention, since the heat radiating means for radiating the heat of the motor housing space for housing the motor to the outside is provided, the cooling performance of the motor can be improved. Further, if the motor housing space is a closed room structure, an excellent waterproof / dustproof function can be realized. Further, if the air flow forming means is provided, the cooling performance of the motor can be further improved.

1 is an external view of an embodiment of a power tool according to the present invention. It is a sectional side view which shows the internal structure of embodiment of the electric tool which concerns on this invention. FIG. 3 is a partial sectional view taken along line AA shown in FIG. 2. It is a disassembled perspective view of the rotation drive part in embodiment of the electric tool which concerns on this invention. It is a sectional side view which shows the internal structure of other embodiment of the electric tool which concerns on this invention. It is a BB partial sectional view shown in FIG.

Next, embodiments of the present invention will be specifically described with reference to the drawings.
The electric power tool according to the present embodiment is an impact driver 1 and includes a housing 2 and a hammer case 3 which are outer frames forming an outer shape with reference to FIGS. 1 to 4. The housing 2 includes a substantially cylindrical body portion 2a extending in the front-rear direction, and a handle portion 2b connected to the body portion 2a so as to form a substantially T shape in a side view. In addition, a notch-shaped engaging recess 2c is formed at two locations on the inner periphery of the body portion 2a. And the rear side of the trunk | drum 2a makes the motor accommodation space 2d which accommodates the motor 4 which is a drive source on the boundary of the engagement recessed part 2c. Further, the front side of the body portion 2a with the engaging recess 2c as a boundary is a reduction gear mechanism housing space 2e for housing the planetary gear mechanism 5 functioning as a speed reduction mechanism portion for decelerating the rotation of the motor 4 and the hammer case 3. It becomes. Inside the hammer case 3 is housed a striking mechanism 6 that converts the rotation of the motor 4 decelerated by the planetary gear mechanism 5 into a rotational striking force and transmits it to a tip tool (not shown).

  The handle 2b of the housing 2 is provided with a switch 8 having a trigger 7 at the upper part and a battery receiving part 9 at the lower part. A battery BT, which is a rechargeable power source, is detachably attached to the battery receiving portion 9 at the lower end of the handle portion 2b.

  In the impact driver 1, when the operator turns on the trigger 7, the switch 8 is turned on and the motor 4 is activated. When the motor 4 is activated, the rotation of the output shaft 4a of the motor 4 is decelerated by the planetary gear mechanism 5 and transmitted to the spindle 10, and the spindle 10 is rotationally driven at a predetermined speed. Here, the spindle 10 is connected to the hammer 11 by a cam mechanism, and the spindle 10 and the hammer 11 connected by the cam mechanism function as the striking mechanism 6. The cam mechanism for connecting the spindle 10 and the hammer 11 includes a V-shaped spindle cam groove 10 a formed on the outer peripheral surface of the spindle 10, and a V-shaped hammer cam groove 11 a formed on the inner peripheral surface of the hammer 11. , A ball 12 engaged with the spindle cam groove 10a and the hammer cam groove 11a, and a spring 13 are provided.

  The hammer 11 is always urged in the distal direction (forward) by the spring 13 and is in a position spaced from the end face of the anvil 14 by engagement between the ball 12 and the cam grooves 10a and 11a when stationary. And the convex part is each formed in the symmetrical position in two places on the rotation plane where the hammer 11 and the anvil 14 oppose each other. The anvil 14 is a part where a not-shown tip tool is detachably mounted.

  As described above, when the spindle 10 is rotationally driven at a predetermined speed, the rotation of the spindle 10 is transmitted to the hammer 11 through the cam mechanism, and the convex portion of the hammer 11 is anvil before the hammer 11 is rotated halfway. 14, the anvil 14 is rotated by engaging with the convex portion 14. When the relative rotation occurs between the hammer 11 and the spring 13 by the engagement reaction force at that time, the hammer 11 becomes a spindle cam of the cam mechanism. While moving the spring 13 along the groove 10a, it starts to move backward toward the motor 4 side.

  When the protrusion of the hammer 11 moves over the protrusion of the anvil 14 by the backward movement of the hammer 11 and the engagement between the two is released, the hammer 11 is elastically accumulated in the sling 13 in addition to the rotational force of the spindle 10. While being accelerated rapidly in the rotational direction and forward by the action of energy and the cam mechanism, it is moved forward, that is, toward the anvil 14 side by the biasing force of the spring 13, and the convex portion of the hammer 11 is again engaged with the convex portion of the anvil 14. Together they start to rotate as a unit. At this time, since a strong rotational impact force is applied to the anvil 14, the rotational impact force is transmitted to a screw (not shown) via a tip tool attached to the anvil 14. Thereafter, the same operation is repeated, and the rotational impact force is intermittently and repeatedly transmitted from the tip tool to the screw, and the screw is screwed into a material to be fastened such as wood.

  The planetary gear mechanism 5 includes a ring gear 15 that is a fixed gear, a pinion 16 (functioning as an input gear) formed at an end of the output shaft 4 a of the motor 4, and two planetary gears 17 that mesh with the ring gear 15 and the pinion 16. (Function as an output gear) and an inner cover 18 that rotatably supports the output shaft 4a of the motor 4 and the spindle 10 respectively. The inner cover 18 is prevented from rotating by engaging with the engaging recess 2 c formed in the body portion 2 a of the housing 2, and is fixed in the body portion 2 a of the housing 2. The inner cover 18 functions as a gear holding portion that holds the planetary gear mechanism 5. The ring gear 15 that is a fixed gear is held by the inner cover 18. Each planetary gear 17 is connected to the spindle 10. A step portion is formed at the front end of the outer periphery of the ring gear 15, and the inner peripheral surface of the inner cover 18 is fitted to the outer peripheral surface excluding the step portion. The inner peripheral surface of the hammer case 3 is fitted to the outer peripheral surface of the stepped portion of the ring gear 15 and the outer peripheral surface of the inner cover 18. Further, an O-ring 22 is fitted as a seal member on the outer periphery of the ring gear 15.

  The motor 4 is a relatively inexpensive brush motor, and is housed and accommodated in the motor housing space 2d. The motor 4 includes a rotor 4b having an output shaft 4a, a magnet 4c, a yoke 4d, a brush block 4e, a brush portion 4f (see FIG. 4), and the like. The magnet 4c and the yoke 4d constituting the stator are cylindrical, and the yoke 4d is disposed on the outer peripheral side of the magnet 4c and is held by the housing 2. A fan 19 is attached to the output shaft 4a. The fan 19 functions as air flow forming means for forming an air flow in the motor housing space 2d.

  An opening is formed in the body portion 2a of the housing 2 that forms the motor housing space 2d, and the opening is made of aluminum, magnesium, or copper having a higher thermal conductivity than the housing 2 made of nylon resin, polycarbonate, or the like. The configured cooling fin (cooling plate) 30 is fitted. The motor housing space 2d has a closed chamber structure in order to prevent the motor 4 from being affected by dust and water droplets. That is, no air window is formed in the housing 2 that forms the motor housing space 2d, and the motor housing space 2d includes the housing 2, the cooling plate 30, and the inner cover 18 (the wall surface of the reduction hammer mechanism housing space 2e). It is a closed space.

  The cooling plate 30 is disposed to face the outer periphery of the yoke 4d, and a gap is provided between the outer periphery of the yoke 4d and the housing 2 and the cooling plate 30. As a result, the fan 19 circulates between the inner peripheral side of the magnet 4c and the outer peripheral side of the yoke 4d, thereby forming an air flow as indicated by a dotted arrow in FIG. Accordingly, the cooling plate 30 is disposed in the air flow passage formed by the fan 19 and functions as a heat radiating means for radiating the heat inside the motor housing space 2d to the outside. Further, as shown in FIG. 3A, the cooling plate 30 is provided with fins 30a that protrude toward the motor housing space 2d. The fins 30a are provided along the air flow (the front-rear direction of the housing 2). Thereby, the contact area of the cooling plate 30 and the air flow is increased, and the heat inside the motor housing space 2d can be radiated more efficiently. In addition, as shown in FIG.3 (b), the cooling plate 31 folded in the shape of a bellows is employ | adopted, and the contact area of the cooling plate 31 and the flow of air and the contact surface with the external air of the cooling plate 31 are set. You may enlarge it. In the present embodiment, the groove plate is formed on the contact surface of the cooling plate 30 with the external air to increase the contact area with the external air. However, the contact surface of the cooling plate 30 with the external air is increased. The fin 30a may be provided.

Note that the housing 2, as shown in FIG. 4, a two-piece housing that is divided into right and left, and a right housing 2 ₁ and left housing 2 _2. A right housing 2 ₁ and left housing 2 ₂ with the top of the (opposite side of the lower handle portion 2b is formed), the wall surface forming a motor accommodating space 2d (body part 2a), the notch 2f They are formed at opposing positions. Accordingly, when joining the right housing 2 ₁ and left housing 2 _2, by sandwiching the cooling plate 30 in the notch 2f, simple and robust (housing together is sandwiched and right housing 2 ₁ and left housing 2 ₂ To be joined with screws). In addition, the cooling plates 30 and 31 have a convex portion at the connection portion with the housing 2, and the housing 2 has a concave portion at the connection portion with the cooling plates 30 and 31, and by fitting them, The cooling plates 30 and 31 can be reliably held by the housing 2.

Moreover, it is necessary to form an opening through which the lead wire 20 of the power source applied to the brush portion 4f is formed in the housing 2 forming the motor housing space 2d. Therefore, by sealing the gap between the opening through which the lead wire 20 passes and the lead wire 20 with the closing material 21 such as silicon, the motor housing space 2d can be more reliably formed into a closed chamber structure. In addition, since the lead wire 20 can be fixed to the housing 2 by the closing member 21, disconnection of the lead wire 20 can be suppressed. The opening through which the lead wire 20 passes may be a groove.

  Further, as shown in FIG. 5 and FIG. 6, cooling plates 32 and 33 each having an extending portion 30 b extending partly toward the yoke 4 d are adopted, and an extension that is a part of the cooling plates 32 and 33 is used. You may comprise so that the protrusion part 30b and the yoke 4d may be made to contact. In this case, the heat accumulated in the yoke 4d can be directly radiated to the outside through the cooling plates 32 and 33. In addition, if the extension part 30b is extended along the axial direction (left-right direction of FIG. 5) of the yoke 4d, the heat dissipation effect can be acquired more.

  Moreover, in the above description, although the example which applied this invention to the cordless impact driver 1 provided with a rechargeable battery was demonstrated, various things which have a motor with a brush as a rotation drive part irrespective of the presence or absence of a cord The present invention can be similarly applied to these electric tools.

  As described above, in the present embodiment, the housing 2 that forms the motor housing space 2d having the closed chamber structure in which the motor 4 is housed, the fan 19 that forms the air flow in the motor housing space 2d, and the fan 19 And a cooling plate 30 that dissipates heat inside the motor housing space 2d to the outside. With this configuration, since heat in the motor housing space can be efficiently radiated to the outside, the brushed motor can be housed in the motor housing space having a closed chamber structure. Accordingly, an excellent waterproof / dustproof function can be realized.

Further, in the present embodiment, the motor 4 is housed in the motor housing space 2d, and the air that circulates between the inner peripheral side of the magnet 4c and the outer peripheral side of the yoke 4d by the fan 19 provided in the rotor 4b. It is comprised so that the flow of may be formed. With this configuration,
An air flow can be efficiently formed in the motor housing space 2d, and the heat dissipation effect can be improved.

  Further, in the present embodiment, the cooling plate 30 is fitted into an opening formed in the housing 2. With this configuration, it is possible to simplify the structure of the heat radiating means for radiating the heat in the motor housing space to the outside.

  Further, in the present embodiment, a part of the cooling plate 30 is in contact with the yoke 4d. With this configuration, the heat accumulated in the yoke 4d can be directly radiated to the outside.

Furthermore, keep the present embodiment, the housing 2 is composed of a right housing 2 ₁ and left housing 2 _2, cooling plate 30 is held sandwiched by the right housing 2 ₁ and left housing 2 ₂ . With this configuration, the structure for holding the cooling plate 30 can be simplified.

  Further, in the present embodiment, the housing 2 includes a body portion 2a that forms a motor housing space 2d, and a handle portion 2b that is connected to the body portion 2a so as to form a substantially T shape in a side view. The cooling plate 30 is provided on the opposite side of the body portion 2a where the handle portion 2b is connected. With this configuration, the cooling plate 30 that is assumed to be relatively hot can be kept away from the operator's hand. Moreover, the heat dissipation effect can be improved without increasing the size of the body portion 2a in the front-rear direction. Further, by providing a heat dissipating means on the outer periphery of the yoke of the motor, the heat of the motor can be efficiently released to the outside.

  Further, in the present embodiment, the housing 2 forming the motor housing space 2d is formed with an opening through which the lead wire 20 of the power source applied to the brush portion 4f passes, and the opening through which the lead wire 20 passes and the lead wire The gap with the sealing member 20 is sealed by the closing member 21. With this configuration, the motor housing space 2d can be more reliably formed into a closed chamber structure.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of these components and the like, and such modifications are within the scope of the present invention. For example, although a motor with a brush has been described as a motor, a brushless motor may be used. A similar effect can be obtained if a heat dissipating means is provided outside the brushless motor. Further, if the brushless motor is disposed in the motor housing space having a closed chamber structure, the dustproof property and the waterproof property can be further improved together with the substrate coating.

DESCRIPTION OF SYMBOLS 1 Impact driver 2 Housing 2a Body part 2b Handle part 2c Engaging recess 2d Motor accommodation space 2e Deceleration hammer mechanism accommodation space 2f Notch 3 Hammer case 4 Motor 4a Output shaft 4b Rotor 4c Magnet 4d Yoke 4e Brush block 4f Brush part 5 Planet Gear mechanism 6 Blowing mechanism 7 Trigger 8 Switch 9 Battery receiving part 10 Spindle 10a Spindle cam groove 10b Spindle collar 11 Hammer 11a Hammer cam groove 12 Ball 13 Spring 14 Anvil 15 Ring gear 15a Protrusion 15aa Ridge line 15b Ring gear stage 15c 16 Pinion 17 Planetary gear 18 Inner cover 19 Fan 20 Lead wire 21 Blocking material 22 O-ring 30, 31, 32, 33 Cooling plate 30a Fin 30b Out portion BT battery

Claims (12)

An electric tool equipped with a motor,
A housing forming a motor housing space in which the motor is housed;
An electric power tool comprising heat radiating means for radiating heat inside the motor housing space to the outside. An air flow forming means for forming an air flow in the motor housing space;
The electric power tool according to claim 1, wherein the heat dissipating means is disposed in a flow path of air flow formed by the air flow forming means. The air flow forming means is a fan provided in a rotor of the motor;
The power tool according to claim 2, wherein an air flow that circulates at least one of an inner peripheral side and an outer peripheral side of the stator of the motor is formed.   The electric power tool according to claim 1, wherein the motor housing space has a closed chamber structure.   The electric power tool according to any one of claims 1 to 4, wherein the heat dissipating means is arranged outside a stator of the motor. The motor is a motor with a brush;
The air flow forming means is a fan provided in a rotor of the brushed motor, and circulates at least one of an inner peripheral side of a magnet of the brushed motor and an outer peripheral side of a yoke of the brushed motor. The power tool according to claim 2, wherein a flow of   The electric power tool according to any one of claims 1 to 6, wherein the heat radiating means is a cooling plate fitted in an opening formed in the housing.   The electric tool according to claim 7, wherein a part of the cooling plate is in contact with a stator of the motor. The housing is composed of a plurality of members,
The power tool according to claim 7 or 8, wherein the cooling plate is sandwiched and held by the plurality of members constituting the housing. The housing includes a body part that forms the motor housing space, and a handle part that is connected to the body part so as to form a substantially T shape in a side view.
The electric power tool according to any one of claims 7 to 9, wherein the cooling plate is provided on the opposite side of the body portion where the handle portion is connected. The motor is a motor with a brush;
The housing that forms the motor housing space has an opening through which a lead wire of a power source applied to the brush portion of the motor is passed,
The power tool according to claim 1, further comprising a closing member that seals a gap between an opening through which the lead wire passes and the lead wire.   The electric power tool according to any one of claims 1 to 11, wherein the heat radiating means is a member having higher thermal conductivity than the housing.

Images