JP2014117792A - Electric power tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric power tool which inhibits intrusion of foreign objects, such as dust, while increasing ventilator windows of cooling air and improving the discharge efficiency when a motor is downsized.SOLUTION: An impact driver 1 includes a division wall 21 which protrudes from an inner peripheral surface of a motor housing 21 to the radial inner side and divides the interior of a housing into a motor chamber MC for housing a motor 4 and a fan chamber FC for housing a fan 5. The division wall introduces outer air suctioned from a suction hole 21a to the fan 5. A part of the division wall is provided at a position overlapping with a fan side portion of the motor in a rotation shaft direction. An exhaust hole 21c forms a bending shape in a thickness direction of the motor housing 21.

Description

  The present invention relates to a hand-held power tool including a cooling fan for cooling a motor.

In general, hand-held power tools such as impact tools are highly demanded for miniaturization and high output.
In order to reduce the size of the electric tool, it is desired to reduce the size of the motor and the cooling fan, increase the cooling air discharge efficiency, and the like. Patent Document 1 proposes a structure for reducing the circulation flow inside the electric power tool as a technique for increasing the cooling air discharge efficiency.

  In addition, hand-held power tools are often used outdoors, and a function to protect them from dust and rainfall is required. Patent Document 2 describes a structure in which dust or the like hardly flows into the tool.

JP 2006-315121 A JP 2010-264534 A

  Here, when the motor is downsized, the amount of heat generated by the motor increases due to the demand for higher output, and durability becomes a problem. Further, when the cooling fan is downsized, the cooling air volume of the cooling fan is reduced, and similarly, the temperature of the motor becomes high and durability becomes a problem.

  In order to increase the cooling air volume according to motor miniaturization or to secure the cooling air volume according to cooling fan miniaturization, a cooling air exhaust hole (wind window) is added to the housing that houses the motor, and the exhaust efficiency It is conceivable to increase. However, when the exhaust holes are added, the area opened inside the tool increases, so that foreign matters such as dust are more likely to enter the tool, resulting in a problem of durability.

  Then, an object of this invention is to provide the electric tool which can implement | achieve size reduction. Another object of the present invention is to provide an electric tool capable of suppressing the intrusion of foreign matters such as dust while increasing the exhaust efficiency by increasing the exhaust holes for cooling air when the motor is downsized. And

  To achieve the above object, the present invention covers a motor having a rotating shaft for driving a tip tool, a fan fixed to the rotating shaft and rotatable integrally with the rotating shaft, and an outer shell of the motor. A housing in which an intake hole and an exhaust hole are formed, and a partition wall that projects radially inward from an inner peripheral surface of the housing and divides the housing into a motor chamber that houses the motor and a fan chamber that houses the fan And a part of the partition wall is provided at a position overlapping the fan side portion of the motor in the direction of the rotation axis.

  Since a part of the partition wall is provided at a position overlapping the fan side portion of the motor in the rotational axis direction, the length of the electric tool in the axial direction of the rotational axis can be reduced by the overlapping length, A small electric tool can be provided. Therefore, a small electric tool can be provided without reducing the motor, and the electric tool can be further downsized if the motor is reduced in size.

  Here, the partition is formed by a ring-shaped rib integrated with the housing. With this configuration, manufacturing by integral molding is easy.

  Further, the thickness of the partition wall gradually increases toward the motor chamber side from the inner peripheral surface of the partition wall toward the housing inner peripheral surface, and the partition wall portion on the housing inner peripheral surface side It is in a position overlapping with the fan side portion of the motor in the direction of the rotation axis.

  Since the thickness of the partition wall gradually increases toward the motor chamber side from the inner peripheral surface of the partition wall toward the inner peripheral surface of the housing, the fan chamber increases as the surface on the motor chamber side of the partition wall moves toward the inner peripheral surface of the partition wall. It is inclined in the direction. As a result, the air flowing from the air intake holes can be guided to the inner diameter side of the fan, and the partition wall can be made thinner while improving the efficiency of the fan. Moreover, since the direction in which the wall thickness increases is on the motor chamber side, the dead space of the motor chamber can be used effectively. Further, if the partition wall is integrated with the housing, the connection portion (base portion) of the partition wall with the housing is thick, so that the connection portion can be prevented from being damaged by vibration or the like.

  Further, according to such a shape, the partition wall portion on the motor chamber side and on the inner peripheral surface side of the housing can be arranged so as to overlap with the fan side portion of the motor when viewed in the axial direction of the rotating shaft. Therefore, the lengths of the power tools in the axial direction of the rotating shaft can be shortened by the overlapping amount.

  The fan is a centrifugal fan, and the exhaust hole is located radially outward of the centrifugal fan. According to such a configuration, the exhaust hole is located immediately downstream in the air discharge direction of the centrifugal fan, and the discharge efficiency can be improved.

  Further, the exhaust hole is bent in the thickness direction of the housing. With such a configuration, it is possible to prevent or suppress entry of foreign matter from the outside into the housing internal space through the exhaust hole. Since foreign matter can be prevented or suppressed from entering the housing through the exhaust hole, the possibility of foreign matter intrusion decreases even if the number of exhaust holes is increased, so that even if a small motor is used, the exhaust efficiency can be improved. It is possible to provide a high-power electric tool.

  The present invention also provides a motor having a rotating shaft for driving a tip tool, a fan fixed to the rotating shaft and rotatable integrally with the rotating shaft, an outer shell of the motor, an intake hole and an exhaust hole. A power tool is provided, wherein the exhaust hole is bent in the thickness direction of the housing.

  As described above, since the exhaust hole is bent in the thickness direction of the housing, it is possible to prevent or suppress entry of foreign matter from the outside into the housing space through the exhaust hole. Since foreign matter can be prevented or suppressed from entering the housing through the exhaust hole, the possibility of foreign matter intrusion decreases even if the number of exhaust holes is increased, so that even if a small motor is used, the exhaust efficiency can be improved. It is possible to provide a high-power electric tool.

  Here, the housing is configured by abutting a plurality of divided housings, and the exhaust hole is formed in the abutting surface. According to such a configuration, even a bent exhaust hole can be easily formed.

  The exhaust hole has an outlet on the outer surface side of the housing, and the outlet faces the tip tool side. According to such a configuration, chips and the like of the workpiece can be blown away with the air ejected from the outlet of the exhaust hole, and the processing visibility can be improved. Further, since air from the outlet of the exhaust hole is not ejected to the worker side, the work is not disturbed.

  The fan is a centrifugal fan, and the exhaust hole is located radially outward of the centrifugal fan. According to such a configuration, the exhaust hole is located immediately downstream in the air discharge direction of the centrifugal fan, and the discharge efficiency can be improved.

  According to the electric tool of the present invention, since the part of the partition wall is provided at a position overlapping the fan side portion of the motor in the rotation axis direction, the length of the electric tool can be reduced, and a small electric tool can be obtained. Can be provided. Therefore, a small electric tool can be provided without reducing the motor, and the electric tool can be further reduced if the motor is reduced in size.

  In addition, the cooling air discharge passage has a bent part, so it is possible to increase the number of cooling air exhaust holes, while increasing the discharge efficiency and suppressing the entry of foreign substances such as dust into the fan chamber, making the motor smaller The amount of cooling air can be increased in accordance with the change in size, or the amount of cooling air can be secured even if the cooling fan is downsized, and the product can be downsized.

The perspective view of the impact driver which is an electric tool by the 1st Embodiment of this invention. Sectional drawing of the impact driver by the 1st Embodiment of this invention. The fragmentary sectional view which shows the flow of the cooling air in the impact driver by the 1st Embodiment of this invention. The fragmentary sectional view which shows the principal part in the impact driver by the 1st Embodiment of this invention. The top view of the impact driver by the 1st Embodiment of this invention. 1 is a partial cross-sectional plan view of an impact driver according to a first embodiment of the present invention. The fragmentary sectional view which shows the flow of the cooling air in the impact driver by the 2nd Embodiment of this invention. The fragmentary sectional view which shows the principal part of the impact driver by the 3rd Embodiment of this invention. The fragmentary sectional view which shows the principal part of the impact driver by the 4th Embodiment of this invention.

  A first embodiment in which the power tool of the present invention is applied to a cordless impact driver will be described with reference to FIGS. 1 to 6. As shown in FIG. 1, the impact driver 1 includes a housing 2 and a detachable battery pack case 2 below the housing 2. As shown in FIG. 2, the housing 2 houses a motor 4, a cooling fan 5, a power transmission mechanism 6 that transmits power to a tip tool (not shown), and the like.

  The housing 2 is made of resin and forms an outline of the impact driver 1, and includes a cylindrical motor housing 21, a handle housing 22 extending downward from the motor housing 21, and a substrate connected to a lower portion of the handle housing 22. It is mainly comprised from the accommodating part 23. FIG. In the following description, the tip tool side is defined as the front side, and the motor 4 side is defined as the rear side. Further, the direction in which the handle housing 22 extends with respect to the motor housing 21 is defined as the lower side, and the opposite is defined as the upper side.

  The housing 2 has a two-divided structure constituted by a right housing 2A and a left housing 2B, and a surface extending in the front-rear direction and the vertical direction at the center in the left-right direction of the housing 2 is a mating surface (divided surface) 2a (FIG. 5). Both housings 2A and 2B are fixed to each other with screws (not shown).

  At positions corresponding to the motor housing 21 of the right housing 2A and the left housing 2B, intake holes 21a (FIG. 2) for taking outside air into the housing 2 for cooling the motor 4 are formed at the rear portions of the right housing 2A and the left housing 2B. A plurality of main exhaust holes 21b are formed in the front part on the side surface side. Further, in the above-described mating surface 2a, a sub exhaust hole 21c is formed at a position corresponding to the upper portion of the motor housing 21. Details of the sub exhaust hole 21c will be described later. A plurality of intake holes 21a (FIG. 5) are also formed on both side surfaces of the motor housing 21 on the rear side of the main exhaust holes 21b.

  A metal hammer case 24 in which the power transmission mechanism 6 is accommodated is disposed inside the front side of the motor housing 21. The hammer case 24 has a substantially funnel shape whose diameter gradually decreases toward the front, and an opening 24a is formed at the front end portion.

  The motor 4 is a brushless DC motor serving as a driving source, and extends in the front-rear direction and is a rotary shaft 41 that is an output shaft that is rotatably supported on the motor housing 21 via a bearing, and a plurality of fixed shafts fixed to the rotary shaft 41. And a stator 45 provided with a plurality of stator coil coils 44 so as to surround the rotor 43. The stator coil 44 is, for example, a star-connected three-phase coil. By making the motor 4 a brushless motor, since there is no electrical sliding part such as a commutator, it is possible to have not only a dustproof effect but also a water resistance effect, and realize high durability as an outdoor device. Is possible.

  A motor drive circuit device 7 for rotationally driving the rotor 43 of the motor 4 is provided on the rear surface of the stator 45 and at a position facing the intake hole 21a. The motor drive circuit device 7 is an inverter circuit that is electrically connected to the stator coil 44 of the brushless motor 4 and includes a known bridge circuit for supplying a drive current to the stator coil 44.

  The cooling fan 5 is a centrifugal fan, and is fixed to the front side portion of the rotating shaft 41 coaxially with the rotating shaft 41. The cooling fan 5 is provided to cool the motor 4 and the motor drive circuit device 7 by generating cooling air in the motor housing 21 by the rotation thereof. The plurality of main exhaust holes 21 b described above are located outward in the radial direction of the centrifugal fan 5.

  A ring-shaped rib 21 </ b> A protruding inward from the inner surface of the motor housing 21 is formed integrally with the motor housing 21 as a partition wall 21. The rib 21A divides the space in the motor housing 21 into a motor chamber MC and a fan chamber FC, and the outside air introduced from the intake hole 21a is directed to the inner diameter side of the fan 5 along the outer shell of the motor 4. Has the function of guiding. Details of the rib 21A will be described later.

  The power transmission mechanism unit 6 is arranged in the axial direction of the rotating shaft 41 of the motor 4 in the order of the speed reduction mechanism 8, the impact mechanism 9, and the anvil unit 10 in this order from the motor 4 side. The speed reduction mechanism 8 includes a sun gear 81 that rotates integrally with the rotation shaft 41, a planetary gear 82 that meshes with the sun gear 81, and a ring gear 82 that meshes with the planetary gear 82. As the sun gear 81 rotates, the planetary gear 82 circulates around the sun gear 81.

  The impact mechanism unit 9 includes a spindle 91, a hammer 92, and a spring 93. The spindle 91 rotates at a position coaxial with the rotation shaft 41 by the revolving motion of the planetary gear 82. The hammer 92 is disposed on the spindle 91 so as to be slidable back and forth, and includes a pair of collision portions 92A at the front end thereof. Further, the hammer 92 is urged forward by a spring 93 to give a striking force, and is configured to move backward against the urging force of the spring 93.

  The anvil portion 10 is disposed in front of the hammer 92 and protrudes forward from the opening 24 a of the hammer case 24, and a rotational impact force is applied by the hammer 92. The anvil part 10 is mainly composed of a tip tool holding part 11 and an anvil 12. The tip tool holding portion 111 is formed in a cylindrical shape and is rotatably supported by the hammer case 24. A holding hole 11 a into which a bit (tip tool) (not shown) is inserted is formed in the front tool holding portion 11 in the front-rear direction, and a bit (not shown) is held at the front end portion of the tip tool holding portion 11. A chuck 13 is provided. Here, the tip tool is, for example, a driver bit or a bolt tightening bit.

  The anvil 12 is configured to be integrated with the tip tool holding portion 11 in the hammer case 24 behind the tip tool holding portion 11 and arranged on the diametrically opposite sides with respect to the rotation center of the tip tool holding portion 11. It has a pair of impacted parts 12A.

  When the hammer 92 rotates, one collision part 92A and one collision target part 12A collide with each other, and at the same time, the other collision part 92A and the other collision target part 12A collide with each other. 12 and the anvil 12 is hit. Further, after the collision between the collision portion 92A and the colliding portion 12A, the hammer 92 moves backward while rotating against the urging force of the spring 93. When the collision part 92A gets over the collision part 12A, the elastic energy stored in the spring 93 is released, the hammer 92 moves forward, and the collision part 92A and the collision part 12A collide again. Become.

  The handle housing 22 has a substantially cylindrical shape, and has an upper end connected to the motor housing 21 and a lower end connected to the substrate housing portion 23. The handle housing 22 is provided with a trigger 15 that is an electronic switch, and the trigger 15 is connected to a switch mechanism 16 accommodated in the handle housing 22. Supply of electric power to the motor 4 and interruption are switched by the trigger 15.

  A control circuit unit 17 connected to the switch mechanism 16 is stored in the substrate storage unit 23. The control circuit 17 has a CPU and the like, and is connected to the motor drive circuit device 7 to control the motor drive circuit device 7.

  A battery pack case 3 serving as a driving power source for the motor 4 is detachably attached to a lower end portion of the handle housing 22. The battery pack case 3 accommodates a battery pack main body made of a lithium ion secondary battery, a nickel / cadmium secondary battery, etc., and most of the battery pack main body is inserted and accommodated in the board accommodating portion 23. The battery pack case 3 is electrically connected to the motor drive circuit device 7 via the trigger 15.

  Next, the operation of the impact driver 1 will be described when tightening screws. When the operator pulls the trigger 15, the motor 4 rotates at a rotation speed corresponding to the pulling margin. At the same time, the cooling fan 5 also rotates, and outside air is taken into the motor housing 21 through the intake holes 21a. The outside air cools the motor drive circuit device 7 and the motor 4 and is discharged to the outside from the main exhaust hole 21b and the sub exhaust hole 21c.

  As the motor 4 rotates, the rotational force of the motor 4 transmitted from the rotating shaft 41 is decelerated by the planetary gear 82 and the ring gear 83, and the reduced rotational force is transmitted to the spindle 91. When a predetermined torque or more is applied to the anvil 12 during screw tightening, the hammer 92 converts the rotational force into a striking force by the action of the spring 93. As a result, the hammer 92 can apply a rotational striking force to the tip tool mounted on the anvil 12 and tighten the screw. The motor 4 stops when the operator releases the trigger 15.

  Next, the flow of the partition wall 21A, the sub exhaust hole 21c, and the cooling air will be described with reference to FIGS. As described above, the partition wall 21 </ b> A partitions the space in the motor housing 21 into the motor chamber MC and the fan chamber FC, and the fan 5 while keeping the outside air introduced from the intake hole 21 a along the outer shell of the motor 4. It has a function to guide to the inner diameter side of. The partition wall 21 </ b> A is formed by a ring-shaped rib centered on the rotational axis of the fan 5, and protrudes radially inward from the inner peripheral surface of the motor housing 21.

  Here, a part of the partition wall 21 </ b> A is provided at a position overlapping the fan 5 side portion of the motor 4 in the direction of the rotation shaft 41. Specifically, the thickness of the partition wall 21A gradually increases from the inner peripheral surface of the partition wall 21A toward the motor chamber MC as it approaches the inner peripheral surface of the motor housing 21, and the partition wall on the inner peripheral surface side of the motor housing 21 is increased. The portion 21 </ b> A is in a position overlapping the portion on the fan 5 side of the motor 4 (the portion of the stator coil 44) in the direction of the rotation shaft 41. That is, in FIG. 4, the length L part overlaps. Since a part of the partition wall 21A is provided at a position overlapping the fan 5 side portion of the motor 4 in the direction of the rotary shaft 41, the electric tool 1 in the axial direction of the rotary shaft 31 is overlapped by the overlapping length L. Can be shortened, and a small electric tool can be provided. Therefore, a small electric tool can be provided without reducing the motor, and the electric tool can be further downsized if the motor is reduced in size.

  Further, since the thickness of the partition wall 21A gradually increases toward the motor chamber MC as it approaches the inner peripheral surface of the motor housing 21 from the inner peripheral surface of the partition wall 21A, the surface of the partition wall 21A on the motor chamber MC side is As it goes toward the inner peripheral surface of the partition wall 21A, it is inclined toward the fan chamber FC. As a result, the air flowing in from the air intake hole 21a passes along the outer shell of the motor 4, and as shown by the arrow F in FIG. The partition wall 21A can be thinned while improving the efficiency of blowing air. Further, since the direction in which the thickness of the partition wall 21A increases is on the motor chamber MC side, the dead space of the motor chamber MC can be effectively used. Further, the brushless motor 4 has a dead space on the outer peripheral portion of the stator 45 (outside of the stator coil 44), and a portion whose thickness increases from the inner diameter side to the outer diameter side of the partition wall 21A can be disposed in this dead space. The product can be downsized. Further, the partition wall 21A can be integrally formed with the motor housing 21, and the manufacturing cost is low.

  As described above, in addition to the plurality of exhaust holes 21b, which are the main exhaust holes, a sub exhaust hole 21c is formed in the upper portion of the motor housing 21. As shown in FIGS. 5 and 6, the sub exhaust hole 21 c is provided in both the right housing 2 </ b> A and the left housing 2 </ b> B, and both are open to the mating surfaces of the left housing 501 and the right housing 502. Provided, the respective mating surfaces are abutted to form one sub exhaust hole 21c. Further, the sub exhaust hole 21 c is located outward of the centrifugal fan 5 in the radial direction.

  The sub exhaust hole 21c has a crank-like bent shape as shown in FIG. Specifically, in the thickness of the motor housing 21, the first passage portion 21c1 that opens to the fan chamber FC and extends in the radial direction of the fan 5 is connected to the first passage portion 21c1 and connected to the first passage portion 21c1. A second passage portion 21c2 extending forward in the axial direction at a substantially right angle, and a third passage connected to the second passage portion 21c2 and extending radially outward at a substantially right angle to the second passage portion 21c2 to open to the outside air It is a bent shape with the portion 21c3.

  Such a shape can prevent or suppress entry of foreign matters such as dust from the outside into the fan chamber FC. Since foreign matter can be prevented or suppressed from entering the housing through the sub exhaust hole 21c, the sub exhaust hole 21c can be added in addition to the main exhaust hole 21b, and the exhaust efficiency can be improved even if a small motor is used. A high output power tool can be provided.

  The right housing 2A and the left housing 2B can be manufactured at low cost by molding them with a mold such as resin molding or aluminum die casting. Here, since the sub exhaust hole 21c is formed to open in the mating surface 2a, the sub exhaust hole 21c can be easily formed by performing die cutting in a direction orthogonal to the mating surface 2a.

  Next, the configuration of the impact driver 101 according to the second embodiment of the present invention will be described with reference to FIG. The same members as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only different portions will be described.

  Similarly to the first embodiment, the impact driver 101 according to the second embodiment of the present invention is configured by a right housing and a left housing in which the housing 102 is divided into left and right, and the auxiliary exhaust hole 121c is formed on the mating surface 102a. The sub-exhaust hole 121c is formed at a position radially outward of the centrifugal fan 5 and above the housing 102, and the partition wall 121A is inward at an axial position similar to that of the first embodiment. It protrudes and the shape is the same. However, the bent shape of the sub exhaust hole 121c is different from that of the first embodiment. Specifically, the auxiliary exhaust hole 121c is opened to the fan chamber FC and inclined to the rear, and the second passage portion 121c2 connected to the first passage portion 121c1 and inclined to the front and opened to the outside air. And form a “Ku” shape. According to such a configuration, in addition to the effect of preventing intrusion of foreign matter, the exhaust is not directed to the worker, and dust remaining on the front work member side can be removed. Reference numeral 121a denotes an intake hole.

  FIG. 8 shows an impact driver 201 according to the third embodiment of the present invention. Unlike the shape of the sub exhaust hole 121c shown in FIG. 7, the sub exhaust hole 221c of this embodiment has a first passage portion 221c1 that opens to the fan chamber FC and extends radially outward, and a first passage portion 221c1. A second passage portion 221c2 connected and extending axially forward at right angles to the first passage portion 221c1, and a third passage portion 221c3 connected to the second passage portion 221c2 and inclined rearward and opened to the outside air. . Since the second passage portion 221c2 and the third passage portion 221c3 intersect each other at an acute angle, it has a structure that can further prevent the intrusion of foreign matters than the sub exhaust hole 21a in the first embodiment. Reference numeral 202 denotes a housing, 202a denotes a mating surface, and 221A denotes a partition wall.

  FIG. 9 shows an impact driver 301 according to the fourth embodiment of the present invention. In the embodiment described above, the centrifugal fan 5 is disposed on the front side of the motor 4, but in the fourth embodiment, the centrifugal fan 5 is disposed on the rear side of the motor 4.

  A motor drive circuit device 7 is disposed on the front side of the motor 4, and an air intake hole (not shown) is a portion of the housing 302 (housing) between the tip of the rotating shaft 41 and the front end of the motor drive circuit device 7 in FIG. 9. 302 on the right housing 302A and the left housing (not shown). That is, it is formed in the housing 302 portion located on the side of the motor drive circuit device 7.

  A partition 321 </ b> A that partitions the motor chamber MC and the fan chamber FC protrudes radially inward from the inner peripheral surface of the housing 302 behind the motor 4. Here, the length of the partition wall 321A in the radial direction is not uniform in the circumferential direction, and is short at the top and long at the bottom. Similarly to the above-described embodiment, a part of the partition wall 321 </ b> A is provided at a position overlapping the fan 5 side portion of the motor 4 in the direction of the rotation shaft 41. Specifically, the thickness of the partition wall 321A gradually increases from the inner peripheral surface of the partition wall 321A toward the motor chamber MC as it approaches the inner peripheral surface of the housing 302, and the thickness of the partition wall 321A on the inner peripheral surface side of the housing 302 is increased. The portion is in a position overlapping the portion on the fan 5 side of the motor 4 in the direction of the rotation shaft 41. With this configuration, the length of the electric tool 301 in the axial direction of the rotating shaft 41 can be shortened by the overlapping length, and a small electric tool can be provided.

  A main exhaust hole (not shown) is formed in the right housing 302 </ b> A constituting the housing 302 and the left housing (not shown) at a radially outward position of the centrifugal fan 5. In addition, sub exhaust holes 321 c are formed at the upper and lower positions of the housing 302, respectively. Similar to the above-described embodiment, the sub exhaust hole 321c is formed in the mating surface 302a, and the position of the sub exhaust hole 321c is outward in the radial direction of the centrifugal fan 5. Each sub exhaust hole 321c has a bent shape similar to that of the first embodiment. In the present embodiment, since the sub exhaust holes 321c can be formed at the upper and lower positions of the housing 302, the number of sub exhaust holes 321c can be increased, and the discharge efficiency can be further enhanced. The bent shape of the sub exhaust hole 321c may be the shape as in the second to third embodiments. Further, in the first to fourth embodiments, the shape of the sub exhaust hole is not limited to a bent shape, and a passage between the inlet and the outlet of the exhaust hole is provided as long as dust or the like does not easily enter the housing. It may be bent.

1: 101, 201, 301 Impact driver 2: 102, 202, 302 Housing 2A, 302A: Right housing 2B: Left housing 2a, 102a, 202a, 302a: Mating surface 4: Motor 5: Centrifugal fan 21: Motor housing 21a, 121a, 221a: Intake holes 21c: 121c, 221c, 321c: Sub exhaust holes 21A, 121A, 221A, 321A: Bulkhead MC Motor room FC Fan room

Claims (9)

A motor having a rotating shaft for driving the tip tool;
A fan fixed to the rotating shaft and rotatable integrally with the rotating shaft;
A housing that covers the outer shell of the motor and has an intake hole and an exhaust hole;
A partition projecting radially inward from the inner peripheral surface of the housing, and partitioning the housing into a motor chamber housing the motor and a fan chamber housing the fan;
A power tool, wherein a part of the partition wall is provided at a position overlapping with a fan side portion of the motor in the direction of the rotation axis.   The power tool according to claim 1, wherein the partition wall is constituted by a ring-shaped rib integrated with the housing.   The thickness of the partition gradually increases from the inner peripheral surface of the partition toward the housing inner peripheral surface toward the motor chamber side, and the partition wall portion on the inner peripheral surface side of the housing The electric power tool according to claim 1, wherein the electric power tool is located at a position overlapping with a fan side portion in the rotation axis direction.   The electric tool according to any one of claims 1 to 3, wherein the fan is a centrifugal fan, and the exhaust hole is located radially outward of the centrifugal fan. The electric power tool according to any one of claims 1 to 4, wherein the exhaust hole is bent in a thickness direction of the housing. A motor having a rotating shaft for driving the tip tool;
A fan fixed to the rotating shaft and rotatable integrally with the rotating shaft;
A housing that covers the outer shell of the motor and has an intake hole and an exhaust hole;
The electric power tool, wherein the exhaust hole is bent in the thickness direction of the housing.   The power tool according to claim 6, wherein the housing is configured by abutting a plurality of divided housings, and the exhaust hole is formed in a butting surface.   The power tool according to claim 6 or 7, wherein the exhaust hole has an outlet on an outer surface side of the housing, and the outlet faces the tip tool side.   The electric tool according to any one of claims 6 to 8, wherein the fan is a centrifugal fan, and the exhaust hole is located radially outward of the centrifugal fan.

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