JP2017019020A - Electric power tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the waterproofness of an electric power tool such as an electric drill to an extent allowing its use even in water or heavy rain.SOLUTION: By using a DC brushless motor as an electric motor 30 serving as a driving source, the watertightness of a housing 10 is enhanced with eliminating the conventional brush powder countermeasures. Air intake and exhaust holes for motor cooling are watertightly closed by attaching a body waterproof cover 40. A battery mounting part to which a battery pack has been mounted is watertightly closed by a battery waterproof cover 54. An electric power tool 1 can be used even in water or heavy rain by these waterproof measures.SELECTED DRAWING: Figure 1

Description

  The present invention mainly relates to a waterproof structure of a power tool such as a screw tightener or an electric drill.

  For example, when using a hand-held power tool called a polisher or sander to polish a metal surface (polishing work), water should be run through the processing site to prevent dust from being scattered. The dust is washed away. For this reason, in this kind of electric tool, high waterproofness is requested | required in addition to normal dustproofness. Patent Document 1 below discloses an electric tool that secures high waterproofness by using a cylindrical housing instead of a normal halved structure.

JP 2014-50921 A

  However, conventionally, if the housing seal (water tightness) is increased to ensure high waterproofness, it is necessary to separately take carbon brush dust countermeasures for the electric motor built in as a drive source. It was insufficient.

  The present invention has an extremely high waterproof property (watertightness) that enables use in the outdoors, for example, in the water or in heavy rain, while taking measures against dust in the housing, and electric measures that have taken measures against dust in the housing The purpose is to provide a tool.

  The above-described problems are solved by the following inventions. 1st invention is equipped with the electric motor as a drive source, the power supply which supplies electric power to an electric motor, and the housing which comprises these in a watertight state, DC brushless motor is equipped as an electric motor, and a battery pack is used as a power supply It is a power tool that can be attached.

  According to the first invention, since the DC brushless motor is built in as the electric motor, it is not necessary to take measures against carbon brush dust required for the brush motor. Thereby, the water-tightness of the housing can be further increased, and the DC brushless motor and the battery pack can be built in, whereby the electric tool can be used in water.

  2nd invention is an electric tool provided with the electric motor as a drive source, the power supply which supplies electric power to an electric motor, and the housing which comprises these in a watertight state. In the second invention, the housing has a housing main body that houses the electric motor. In the second invention, the housing body is provided with an intake hole and an exhaust hole for intake and exhaust of the motor cooling air. A main body waterproof cover for watertightly closing the intake hole and the exhaust hole can be attached to the housing main body.

  According to the second invention, the main body waterproof cover is removed from the housing main body, and the intake holes and the exhaust holes are exposed to the outside, so that outside air (motor cooling air) is introduced into the housing main body to cool the electric motor. The electric tool can be used in a state where A waterproof body (watertightness) in the housing body can be improved by attaching a waterproof cover to the housing body and watertightly sealing the intake and exhaust holes, so that the electric tool can be used, for example, underwater. become.

  3rd invention is an electric tool provided with the electric motor as a drive source, the power supply which supplies electric power to this electric motor, and the housing which equips these in a watertight state. In 3rd invention, the housing has the housing main-body part which accommodates an electric motor, and becomes a structure which provided the window part which exposes the heat sink exposed to the electric motor to the housing main-body part outside. Yes.

  According to the third invention, the electric motor is efficiently cooled by air cooling or water cooling via the heat radiating plate. In 3rd invention, the said electric tool can be used in water, for example, by ensuring the watertight state between a window part and a heat sink.

  4th invention is an electric tool provided with the electric motor as a drive source, the power supply which supplies electric power to this electric motor, and the housing which equips these in a watertight state. In the fourth invention, the housing has a housing main body portion that houses the electric motor, and a housing grip portion that extends laterally from the housing main body portion, and a battery pack as a power source is attached to the tip of the housing grip portion. A battery mounting portion is included. In the fourth invention, a battery waterproof cover for watertightly covering the battery pack is provided on the battery mounting portion.

  According to the fourth invention, the battery pack is attached in a watertight state by the battery waterproof cover. By increasing the waterproofness of the battery pack, the electric tool can be used, for example, underwater.

  5th invention is the electric tool which provided the window part which exposes the heat sink which contacted the controller which controls operation | movement of an electric motor to the battery attachment part in 4th invention.

  According to the fifth aspect, the controller is efficiently cooled by air cooling or water cooling via the heat sink. In 5th invention, the said electric tool can be used in water, for example, by ensuring the watertight state between a window part and a heat sink.

It is a longitudinal cross-sectional view of the whole electric tool. This figure shows a sectional view taken along line (I)-(I) in FIG. It is a longitudinal cross-sectional view of the whole electric tool. This figure shows a sectional view taken along line (II)-(II) in FIG. It is a cross-sectional view of the main-body part of an electric tool. This figure shows a cross-sectional view taken along line (III)-(III) in FIG. It is a front view of the electric tool which concerns on embodiment of this invention. This figure is the figure which looked at the electric tool from the arrow (IV) direction in FIG. FIG. 5 is a sectional view taken along line (V)-(V) in FIG. 4. This figure is the figure which looked at the cross section of the tool main-body part from the downward direction. It is a (VI)-(VI) sectional view taken on the line in FIG. This figure has shown the longitudinal cross-sectional view of the rear part side of a tool main-body part. It is the (VII)-(VII) sectional view taken on the line in FIG. It is the (VIII)-(VIII) sectional view taken on the line in FIG. It is the (IX)-(IX) sectional view taken on the line in FIG. FIG. 2 is a cross-sectional view taken along line (X)-(X) in FIG. 1.

  Next, an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, in the present embodiment, a hand-held rotary tool that can be used as, for example, an electric drill is illustrated as the electric tool 1. The electric tool 1 includes a tool main body 2 in which an electric motor 30 as a drive source is housed in a housing 10, and a grip 3 that extends sideways from the side of the tool main body 2.

  A housing 10 of the electric power tool 1 is a resin housing in which a cylindrical housing main body 11 constituting the tool main body 2 and a housing grip 12 constituting the grip 3 are integrally formed. It is an integral housing that does not have a split structure. The inside of the cylindrical housing main body 11 is roughly divided forward and backward by an intermediate partition wall 13. An electric motor 30 is provided inside the housing main body 11 and behind the intermediate partition wall 13. Details of the tool body 2 are shown in FIG.

  The electric motor 30 is a DC brushless motor. The electric motor 30 includes a stator 31 in which a drive coil is wound around each tooth portion of the stator core 31 a via an insulating layer, and a rotor 32 that is rotatably supported on the inner peripheral side of the stator 31. I have. The stator 31 is fixed to the inner peripheral side of the housing body 11 through a stator frame 33. The stator cores 31 a are fixed to each other with their outer peripheral surfaces in contact with the inner peripheral surface of the stator frame 33. A window portion 11 c provided in the housing body 11 is located on the outer peripheral side of the stator frame 33. The window part 11c will be described later.

  A motor shaft 34 that rotatably supports the rotor 32 is rotatably supported with respect to the housing body 11 via two front and rear bearings 35 and 36. The front bearing 35 is held by the intermediate partition wall 13, and the rear bearing 36 is held by the rear part of the housing body 11. A cooling fan 37 is attached to the motor shaft 34 between the rear bearing 36 and the rotor 32. As shown in the drawing, the rear bearing 36 is disposed so as to overlap the cooling fan 37 in the axial direction of the motor shaft 34 (motor axial direction). A baffle plate 38 is disposed around the cooling fan 37. The baffle plate 38 protrudes to the position where the periphery of the baffle plate 38 comes into contact with the inner peripheral surface of the housing body 11. When the cooling fan 37 is rotated by the activation of the electric motor 30, the baffle plate 38 generates a flow of motor cooling air that flows from the front side to the rear side of the baffle plate 38.

  A sensor substrate 39 is attached along the front end surface of the stator 31. A plurality of magnetic sensors for detecting the rotational position of the rotor 32 are attached to the rear surface of the sensor substrate 39 (opposite surface on the rotor 32 side).

  The front portion of the motor shaft 34 protrudes forward from the intermediate partition wall 13. Three stages of planetary gear trains 14 to 16 are connected to the motor shaft 34 in series. The three-stage planetary gear trains 14 to 16 are housed in a gear chamber that is partitioned on the front side by a front case 19, on the back side by an intermediate partition wall 13, and surrounded by a gear housing 20 in an oil-tight manner. . As shown in FIG. 2, the gear housing 20 is coupled to the front case 19 side by four fixing screws 20a. By dividing the gear chamber by the gear housing 20 or the like, scattering around the grease applied to the planetary gear trains 14 to 16 is prevented.

  A spindle 17 is coupled to the output side (carrier) of the third stage planetary gear train 16. The rotational output of the electric motor 30 is decelerated by the three-stage planetary gear trains 14 to 16 and output to the spindle 17. A chuck portion 18 for attaching a tip cutter (not shown) such as a drill bit is attached to the tip of the spindle 17. The spindle 17 is rotatably supported by the front case 19 via two front and rear bearings 17a and 17b.

  As shown in FIG. 4, the front case 19 is coupled to the front portion of the housing body 11 by four fixing screws 21. An O-ring 19 a is interposed between the front portion of the housing body 11 and the front case 19. The front case 19 is watertightly coupled to the front portion of the housing body 11 by the O-ring 19a. A front end portion of the spindle 17 protrudes from the front case 19, and a chuck portion 18 is attached to the protruding portion. Further, on the inner peripheral side of the front case 19, a seal member 19b is attached to the front side of the front bearing 17a. The seal member 19b shields the inner peripheral side of the front case 19 from the outside in a watertight manner.

  A watertight part 11 a that is stepped on the small diameter side is provided at the rear part of the housing body 11. As shown in FIG. 6, a plurality of window portions 11b are provided on the left and right sides of the watertight portion 11a. As shown in FIG. 5, each window portion 11 b is partitioned by a baffle plate 38 into a front side and a rear side. The front side of each window portion 11b is an intake hole 11ba, and the rear side is an exhaust hole 11bb. When the cooling fan 37 is rotated by the activation of the electric motor 30, outside air is sucked from the front intake holes 11ba. The outside air sucked into the housing main body 11 mainly cools the stator 31, the rotor 32, the sensor substrate 39, etc. of the electric motor 30. The outside air introduced as the motor cooling air is exhausted to the outside from the inner peripheral side of the baffle plate 38 through the rear exhaust hole 11bb.

  A resin-made main body waterproof cover 40 can be attached to the watertight part 11a. The main body waterproof cover 40 is attached in a state of covering the entirety of the watertight part 11 a via the O-ring 41. By this main body waterproof cover 40, each window part 11b of the watertight part 11a will be in the state sealed watertight. As shown in FIGS. 5 and 6, a retaining protrusion 40 a is provided on the inner peripheral surface of the main body waterproof cover 40. Each of the retaining protrusions 40a is engaged with the window 11b, thereby preventing the main body waterproof cover 40 from being accidentally dropped. By utilizing the elastic deformation of the main body waterproof cover 40, each retaining protrusion 40a can be engaged with and disengaged from the window portion 11b, whereby the main body waterproof cover 40 is attached to and removed from the watertight portion 11a. Can do.

  When the electric tool 1 is used in a normal environment (in the atmosphere), the motor cooling air can be introduced into the housing main body 11 by removing the main body waterproof cover 40. On the other hand, by attaching the main body waterproof cover 40 to the watertight part 11a, the electric tool 1 can be used, for example, in water. By attaching the main body waterproof cover 40, all the intake holes 11ba and all the exhaust holes 11bb are closed in a watertight manner, and water intrusion into the housing main body 11 is prevented. In this case, the electric motor 30 is cooled (air-cooled or water-cooled) by the window portion 11c described below.

  The window portion 11 c is disposed on the side of the stator frame 33. The window portion 11c is provided at a plurality of locations at appropriate intervals in the circumferential direction on the side portion of the housing main body portion 11. Opposing the window portion 11c, a submerged stepped portion 33a that is one step lower is provided on the outer peripheral surface of the stator frame 33. The water that has entered from each window portion 11c is directly contacted over the entire outer peripheral surface of the stator frame 33 through the water immersion step portion 33a. The stator frame 33 is cooled by the water that has entered from the window portion 11c contacting the entire circumference. When the stator frame 33 is cooled by water, the stator core 31a and the stator 31 that are in direct contact with the inner peripheral surface of the stator frame 33 are cooled.

  O-rings 42 and 43 are interposed between the stator frame 33 and the inner peripheral surface of the housing main body 11 before and after the water immersion step portion 33a of the stator frame 33, respectively. O-rings 42 and 43 prevent water that has entered from the window portion 11 c from entering the inner peripheral side of the housing main body portion 11.

  A switch lever 4 that is pulled by a user with a fingertip is disposed on the front surface of the grip portion 3. The switch lever 4 is covered with a cover portion 12a provided integrally with the housing grip portion 12 by two-color molding. By this cover portion 12a, the gap between the window portion 12b of the housing grip portion 12 and the switch lever 4 is closed in a watertight manner. On the rear side of the switch lever 4, a switch body 22 is supported inside the housing grip portion 12. When the switch lever 4 is pulled with a fingertip, the switch body 22 is turned on. When the switch body 22 is turned on, the electric motor 30 is activated, and the spindle 17 rotates at high speed around the axis.

  Further, a forward / reverse switching lever 23 for switching the rotation direction of the electric motor 30 is provided near the base of the grip portion 3. Both end portions of the forward / reverse switching lever 23 protrude left and right. Similar to the switch lever 4, the left and right protruding portions are watertightly covered with a cover portion 23 a formed in two colors when the housing grip portion 12 is formed.

  A battery mounting portion 50 is provided at the tip of the grip portion 3. One battery pack 5 is attached to the battery attachment portion 50. The electric motor 30 is activated using the battery pack 5 as a power source. The battery pack 5 can be repeatedly used by removing it from the battery mounting portion 50 and charging it with a separately prepared charger. The battery attachment portion 50 includes an attachment base portion 51 that is integrally formed with the lower portion of the housing grip portion 12. The mounting base portion 51 is provided in a state of projecting laterally from the lower portion of the housing grip portion 12.

  On the lower surface side of the mounting base portion 51, a pair of left and right slide rail portions 61 for mechanically connecting the battery pack 5 and a positive and negative terminal plate 62 for electrical connection are provided. As shown in FIGS. 2 and 9, the pair of left and right slide rail portions 61 are provided in a sub housing 61 a having a left and right halved structure. The left and right sub-housings 61a are coupled to each other by three fixing screws 61b as shown in FIG. As shown in FIGS. 7 to 10, the sub-housings 61a having a halved structure coupled to each other are fixed to the battery mounting portion 51 with fixing screws 61c.

  A positive and negative terminal plate 62 electrically connected to the battery pack 5 and a controller 60 for controlling the operation of the electric motor 30 are supported by the half housing sub housing 61a. The controller 60 is a case in which the control circuit board 65 is accommodated in a rectangular bottom shallow case and molded with resin, and positive and negative terminal plates 62 are insert-molded on the bottom surface of the case and integrally provided. The power of the battery pack 5 supplied through the positive and negative terminal plates 62 is supplied from the control circuit board 65 of the controller 60 to the electric motor 30 through the power line 63. As shown in FIG. 1, the power supply line 63 rises upward from the upper surface of the controller 60 and is wired upward in the housing grip portion 12. The power line 63 is connected to the sensor substrate 39 of the electric motor 30. Various wirings such as a signal line to the switch body 22 are connected to the connector connecting portion provided on the upper surface of the control circuit board 65. A capacitor 65 a and a plurality of switching elements (FETs) are mounted on the upper surface of the control circuit board 65.

  The battery pack 5 uses a lithium ion battery in which a plurality of cells are housed in a generally rectangular parallelepiped case having six surfaces. The battery pack 5 can also be used as a power source for other electric tools such as a screw tightener and a cutting machine, and a highly versatile battery pack that can be used as a power source for the electric tool 1 of the present embodiment is used. ing. In this embodiment, a lithium ion battery with an output voltage of 18V is used. As shown by the white arrow in FIG. 1, the battery pack 5 is attached to the battery attachment portion 50 by sliding backward, and can be detached from the battery attachment portion 50 by sliding forward. The battery pack 5 is mechanically attached to the battery attachment base portion 51 by engaging a rail portion provided on the upper surface thereof with a rail receiving portion on the battery attachment base portion 51 side.

  The battery mounting portion 50 is provided with a battery waterproof cover 54 for watertightly covering the battery pack 5, the positive / negative terminal plate 62, the controller 60, and the like. The battery waterproof cover 54 is supported on the rear portion of the attachment base portion 51 via a support shaft 53 so as to be opened and closed up and down. Buckle-shaped fasteners 55 are respectively provided on the left and right sides of the battery waterproof cover 54. The battery waterproof cover 54 is locked in a closed state by hooking the clasps 55a of the left and right fasteners 55 on a hook 51a integrally provided on the side of the mounting base 51 and tilting the lever 55b to the lock side. Is done. The battery waterproof cover 54 can be opened by raising the lever 55b to the unlock side and removing the clasp 55a from the hook 51a. As shown in FIGS. 2 and 7 to 10, a seal ring 54 a is attached to the opening edge of the battery waterproof cover 54. With this seal ring 54a, the battery mounting space formed between the battery base cover 51 and the mounting base 51 is kept watertight when the battery waterproof cover 54 is closed.

  A water cooling window 56 is also provided on the front side of the mounting base 51. As shown in FIGS. 1 and 9, the lower portion (bottom portion) of the window portion 56 is watertightly closed by a heat radiating plate 57 fitted with a seal ring 58. The heat sink 57 is sandwiched and fixed between the lower portion of the window portion 56 and the upper surface of the controller 60. The controller 60 (mainly switching element) is efficiently cooled by the heat sink 57 being in contact. In particular, when the electric tool 1 is used underwater, the controller 60 is efficiently cooled by water cooling when water enters the window portion 56 and contacts the heat radiating plate 57.

  According to the electric tool 1 of the present embodiment configured as described above, since the DC brushless motor (electric motor 30) is incorporated as a drive source, the brush powder as in the case of using the brush motor as the drive source can be obtained. As a result, it is not necessary to take dust countermeasures for the carbon brush. Thereby, the water tightness of the housing main body 11 can be further improved, and the DC brushless motor 30 can be built in, so that at least the tool main body 2 of the electric power tool 1 can be used, for example, outdoors in water or heavy rain. can do.

  Further, according to the illustrated embodiment, the watertight part 11a of the housing main body part 11 is provided with the intake hole 11ba and the exhaust hole 11bb for sucking and exhausting motor cooling air. With the intake hole 11ba and the exhaust hole 11bb, the DC brushless motor 30 is cooled (air-cooled) when the electric tool 1 is used in a normal environment (in the atmosphere). On the other hand, since the main body waterproof cover 40 is attached to the watertight portion 11a of the housing main body portion 11, the intake hole and the exhaust hole can be watertightly closed. For example, it can be used in water or in heavy rain.

  Furthermore, according to the illustrated embodiment, the battery pack 5 can be accommodated in an extremely high watertight state by closing the battery waterproof cover 54 in the battery mounting portion 50. In this respect, at least the battery mounting portion 50 of the electric power tool 1 can be used in water or in heavy rain.

  As described above, according to the illustrated embodiment, the motor cooling intake hole 11ba and the exhaust hole 11bb are watertightly closed by the main body waterproof cover 40, and the front case 19 is watertightly attached to the housing main body 11 by the O-ring 19a. The front case 19 and the spindle 17 are connected and sealed with a sealing member 19b to ensure high water tightness of the tool body 2. Further, in the grip part 3, the switch lever 4 is watertightly closed by the cover part 12a. Further, the watertightness of the battery mounting portion 50 to which the battery pack 5 is attached is ensured by the battery waterproof cover 54. From the above, high water-tightness is ensured for the entire power tool 1, and thus the power tool 1 can be used in water or heavy rain (completely waterproof specification).

  Further, according to the illustrated embodiment, the tool main body 2 is provided with the water cooling window 11c so that the stator 31 is mainly cooled efficiently by water cooling during use in water or heavy rain. It has become. Furthermore, a water cooling window 56 is also provided on the attachment base 51 of the battery attachment 50. According to the window portion 56, when the electric power tool 1 is used in water or heavy rain, the controller 60 having a heat source such as a switching element is efficiently cooled. From the above, even when the electric tool 1 is used in a completely waterproof specification, the electric motor 30 and the controller 60 are cooled, thereby improving the stable operation performance and durability of the electric tool 1. .

  Various modifications can be made to the embodiment described above. For example, although the housing 11 that does not have a left / right halved structure has been illustrated, an equivalent effect can be obtained by taking an appropriate waterproof measure for a housing having a halved structure.

  Moreover, although the structure which uses what can be used also as a power supply of another electric tool as the battery pack 5 was illustrated, it can apply similarly also to the electric tool which incorporated the battery pack for exclusive use. If the battery is a built-in battery, it is not necessary to remove it from the housing by making it chargeable while being built-in, and the battery waterproof cover 54 as exemplified in this respect can be omitted to further enhance the watertightness of the electric power tool 1. it can.

  Furthermore, although the slide-mounted battery pack 5 has been illustrated, the illustrated waterproof structure can also be applied to a configuration in which a plug-in stick-type battery pack is mounted as a power source.

  Although the electric drill is exemplified as the electric power tool 1, an equivalent effect can be obtained by applying the waterproof structure exemplified for the screw tightening machine, the polisher, the grinder, the cutting tool and the like.

DESCRIPTION OF SYMBOLS 1 ... Electric tool 2 ... Tool main-body part 3 ... Grip part 4 ... Switch lever 5 ... Battery pack 10 ... Housing 11 ... Housing main-body part 11a ... Watertight part, 11b ... Window part, 11ba ... Intake hole, 11bb ... Exhaust hole 11c ... Window portion 12 ... Housing grip portion, 12a ... Cover portion, 12b ... Window portion 13 ... Intermediate partition walls 14-16 ... Planet gear train 17 ... Spindle, 17a, 17b ... Bearing 18 ... Chuck portion 19 ... Front case, 19a ... O Ring, 19b ... Seal member 20 ... Gear housing, 20a ... Fixing screw 21 ... Fixing screw 22 ... Switch body 23 ... Forward / reverse switching lever, 23a ... Cover part 30 ... Electric motor 31 ... Stator, 31a ... Stator core 32 ... Rotor 33 ... Stator frame, 33a ... Submerged step 34 ... Motor shaft 35, 36 ... Bearing 37 ... Cooling fan 38 ... Back Ruplate 39 ... sensor substrate 40 ... main body waterproof cover 41 ... O-ring 42, 43 ... O-ring 50 ... battery mounting portion 51 ... mounting base portion, 51a ... hooking portion 53 ... support shaft 54 ... battery waterproof cover, 54a ... seal Ring 55 ... Fastener, 55a ... Clasp, 55b ... Lever 56 ... Window 57 ... Heat sink 58 ... Seal ring 60 ... Controller 61 ... Slide rail part, 61a ... Sub housing, 61b, 61c ... Fixing screw 62 ... Terminal plate (positive and negative)
65 ... Control circuit board, 65a ... Capacitor

Claims (5)

An electric motor as a drive source, a power source that supplies electric power to the electric motor, and a housing that houses these in a watertight state,
An electric tool in which a DC brushless motor is incorporated as the electric motor and a battery pack can be attached as the power source. An electric motor as a drive source, a power source that supplies electric power to the electric motor, and a housing that houses these in a watertight state,
The housing has a housing main body that accommodates the electric motor, and the housing main body includes an intake hole and an exhaust hole for sucking and exhausting motor cooling air, and the intake hole and the exhaust hole are watertight. A power tool that can be fitted with a waterproof cover to close it. An electric motor as a drive source, a power source that supplies electric power to the electric motor, and a housing that houses these in a watertight state,
The housing has a housing main body portion that houses the electric motor, and the housing main body portion is provided with a window portion that exposes a heat radiating plate in contact with the electric motor to the outside. An electric motor as a drive source, a power source that supplies electric power to the electric motor, and a housing that houses these in a watertight state,
The housing has a housing main body portion that houses the electric motor, and a housing grip portion that extends laterally from the housing main body portion, and a battery for attaching a battery pack as the power source to the tip of the housing grip portion. An electric tool having an attachment portion and provided with a battery waterproof cover for watertightly covering the battery pack on the battery attachment portion. 5. The electric tool according to claim 4, wherein the battery mounting portion is provided with a window portion that exposes a heat radiating plate in contact with a controller that controls the operation of the electric motor.

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