JP2016097480A - Electric power tool and portable cutting machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric power tool including a motor housing with an excellent water resistance structure, and to provide a portable cutting machine.SOLUTION: The motor housing 20 comprises first and second housing members that have a mating surface parallel to a rotation axis 10a of a motor 10 and perpendicular to a base 5 and is alternatively combined with each other. The motor housing 20 includes a water draining hole 24 linked to the mating surface and positioned between a bottom of the motor housing 20 and the motor 10 in a direction of the rotation axis 10a. Notches provided in the first and second housing members are combined to define the water draining hole 24.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an electric tool including a motor housing having an air window for taking in cooling air and a portable cutting machine.

  Normally, a motor housing that houses a motor in an electric tool has a wind window for taking in cooling air. The wind window serves as an entrance for water during outdoor work in rainy weather, for example. The following Patent Document 1 discloses a portable cutting machine using a brushless motor as a drive source. When the drive source is a brushless motor, since there is no brush portion, the water resistance is higher than when the drive source is a motor with a brush.

JP2012-735A

  Although the water resistance effect is enhanced by using a brushless motor as the drive source, an electric tool and a portable cutting machine having a higher water resistance effect are desired.

  The present invention has been made in view of such a situation, and an object thereof is to provide an electric tool and a portable cutting machine including a motor housing having a structure excellent in water resistance.

One embodiment of the present invention is a power tool. This electric tool
A motor having a rotating shaft;
A bottomed cylindrical motor housing covering the motor;
A fan capable of rotating integrally with the rotating shaft and generating fan air in the motor housing;
The motor housing is composed of two housing members having a mating surface parallel to the rotating shaft and combined with each other,
Each housing member is provided with a plurality of wind windows for communicating the inside of the motor housing with the outside air,
The motor housing is provided with a hole portion connected to the mating surface and positioned between the motor housing bottom and the motor in the rotation axis direction.

  The housing member and the wind window are molded by molding, and the wind window is located on the bottom side of the motor housing with respect to the rotation axis direction and between the mating surfaces in the circumferential direction of the motor housing. May be provided.

  Screw fixing portions for fixing the housing members to each other may be provided on both sides of the wind window in the circumferential direction of the motor housing.

The motor is a brushless motor;
A substrate connected to the coil of the brushless motor is provided between the brushless motor and the bottom of the motor housing,
The hole may be provided between the substrate and the bottom of the motor housing in the rotation axis direction.

  The substrate may be provided with a rotation detection unit that detects a rotation position of the rotation shaft.

  The fan may be provided on the opposite side of the bottom of the motor housing with respect to the motor.

A rotating tool that rotates in response to rotation of the rotating shaft;
A base connected to the motor housing and sliding on the work material;
The hole may be provided on the base side.

  The hole may be connected to the bottom of the motor housing.

Another aspect of the present invention is a portable cutting machine. This portable cutting machine
A motor having a rotating shaft;
A bottomed cylindrical motor housing covering the motor;
A rotating tool that rotates in response to rotation of the rotating shaft;
A base connected to the motor housing and sliding on the work material;
A fan capable of rotating integrally with the rotating shaft and generating fan air in the motor housing;
The motor housing is provided with a plurality of wind windows for communicating the inside of the motor housing with the outside air,
The wind window is provided between the motor and the bottom of the motor housing and at a position closest to the base side in the circumferential direction of the motor housing.

  It should be noted that any combination of the above-described constituent elements, and those obtained by converting the expression of the present invention between methods and systems are also effective as aspects of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, an electric tool provided with the motor housing of the structure excellent in water resistance and a portable cutting machine can be provided.

The front view of the electric tool 1 which concerns on Embodiment 1 of this invention. FIG. 3 is a front sectional view of the electric power tool 1. The right view of the electric tool 1. FIG. The front sectional view of the state where the electric power tool 1 is placed on the floor surface 50. The perspective view which looked at the 2nd motor housing 22 of electric tool 1 from the inside. The perspective view which looked at the 2nd motor housing 22 from the outside. The right view of the electric tool 2 which concerns on Embodiment 2 of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent component, member, etc. which are shown by each drawing, and the overlapping description is abbreviate | omitted suitably. In addition, the embodiments do not limit the invention but are examples, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

Embodiment 1
FIG. 1 is a front view of a power tool 1 according to Embodiment 1 of the present invention. FIG. 2 is a front sectional view of the electric power tool 1. FIG. 3 is a right side view of the power tool 1. In FIG. 1 to FIG. 3, vertical and horizontal directions and front and rear directions are defined. FIG. 4 is a front sectional view of the electric tool 1 placed on the floor 50. FIG. 5 is a perspective view of the second motor housing 22 of the electric power tool 1 as viewed from the inside. FIG. 6 is a perspective view of the second motor housing 22 as seen from the outside.

  The electric tool 1 is a portable cutting machine (portable circular saw), and includes a main body 3 and a base 5. The base 5 is a substantially rectangular plate made of metal such as aluminum. The longitudinal direction of the base 5 coincides with the cutting direction. The bottom surface of the base 5 is a sliding surface with the work material. The main body 3 is supported so as to be able to tilt to the left and right with respect to the base 5 by the tilt position adjusting mechanism 6 and to be able to rotate up and down with respect to the base 5 by the cutting depth adjusting mechanism 7.

  The main body 3 includes a motor housing 20, a gear cover 30 as a cover, and a handle housing 40, which are combined and integrated with each other. The motor housing 20 has a bottomed cylindrical shape that covers the motor 10 and the fan 11. A bearing 10 b that supports one end of a rotating shaft (output shaft) 10 a of the motor 10 is held at the bottom of the motor housing 20. The motor 10 is a brushless motor in the illustrated example. The fan 11 can rotate integrally with the rotating shaft 10 a of the motor 10 and generates fan air (cooling air) in the motor housing 20. The fan 11 is provided on the opposite side of the bottom 20 a of the motor housing 20 with respect to the motor 10. The fan wind is sucked from a wind window 23 described later and cools the motor 10. A substrate 13 connected to the coil of the motor 10 is provided between the motor 10 and the bottom 20 a of the motor housing 20. The substrate 13 includes a plurality of switching elements 14 such as FETs and IGBTs for supplying current to the motor 10, and a hall element that constitutes a rotation detection unit that detects the rotation position of the motor 10 (the rotation position of the rotation shaft 10 a). Etc. are provided. For example, three magnetic sensors 17 are provided around the rotation shaft 10a at intervals of 60 °.

  The gear cover 30 is made of, for example, metal, and supports the rotating shaft 10a of the motor 10 and a speed reduction mechanism (rotation transmission mechanism) 12 that decelerates the rotation of the rotating shaft 10a. Cover the upper half. A saw cover that covers the upper half of the circular saw blade 15 may be combined with the gear cover 30 as a separate body. The rotation of the motor 10 is decelerated by the reduction mechanism 12 and transmitted to the circular saw blade 15. The protective cover 16 is made of, for example, resin, and is provided so as to be rotatable along the outer edge of the gear cover 30. When the cutting operation is not performed, the lower half of the circular saw blade 15 (projected downward from the bottom surface of the base 5). Cover part) except the front part.

  The handle housing 40 includes, for example, a resin cover side handle portion 41 and an anti-cover side handle portion 42 which are combined with each other. As shown in FIG. 3, the handle housing 40 is provided with a trigger switch (operation switch) 47 for the user to control the driving of the motor 10. The handle housing 40 is also provided with a control circuit storage 48 at a position behind the motor housing 20. A control circuit board that controls the rotation of the motor 10 is housed in the control circuit housing section 48.

  As shown in FIG. 3, the motor housing 20 includes a first housing member 21 and a second housing made of, for example, resin and having a mating surface parallel to the rotating shaft 10 a of the motor 10 and substantially perpendicular to the base 5. Housing member 22. Each of the first housing member 21 and the second housing member 22 has a plurality of wind windows 23 that allow the inside of the motor housing 20 to communicate with the outside air, and is preferably molded by molding so as to have a plurality of wind windows 23. Is done. The plurality of wind windows 23 are provided closer to the bottom 20a of the motor housing 20 than the motor 10 in the direction of the rotation axis 10a, and between the mating surfaces in the circumferential direction of the motor housing 20 (the direction around the rotation axis 10a). (Arranged). In the illustrated example, the plurality of wind windows 23 open to the bottom 20 a of the motor housing 20.

  Screw fixing portions for fixing the first housing member 21 and the second housing member 22 to each other are provided on both sides of the plurality of wind windows 23 in the circumferential direction of the motor housing 20. Specifically, the first housing member 21 is provided with two screw holes 25 as shown in FIG. 2, and the second housing member 22 has two screw bosses as shown in FIG. 26 are provided, and the two screws 27 shown in FIG. 3 pass through the screw fastening holes 25 and are screwed into the screw bosses 26. Further, as shown in FIG. 5, a bearing holding portion 28 for holding the bearing 10b shown in FIG.

  As shown in FIG. 2, the motor housing 20 is provided with a drain hole 24 that is connected to the mating surface and is located between the bottom 20 a of the motor housing 20 and the motor 10 in the direction of the rotation shaft 10 a. The drain hole 24 is preferably provided between the substrate 13 and the bottom 20a of the motor housing 20 in the direction of the rotation axis 10a. In the illustrated example, the drain hole 24 is provided at a position connected to the bottom 20 a (inner bottom) of the motor housing 20. As shown in FIG. 5, the second housing member 22 is provided with a notch 24a connected to the mating surface with the first housing member 21, and the first housing member 21 is similarly provided with a notch. Both notches are combined to form a drain hole 24 shown in FIG. The drainage hole 24 is located on the base 5 side in the circumferential direction of the motor housing 20. As shown in FIG. 4, the drain hole 24 may be opened at a position that is the lowest in the vertical direction in the internal space of the motor housing 20 when the electric tool 1 is placed on the horizontal floor surface 50.

  According to the present embodiment, the following effects can be achieved.

(1) Since the motor housing 20 has the drain hole 24, the water that has entered the motor housing 20 from the wind window 23 is discharged from the drain hole 24 to the outside. The risk of failure due to flooding can be reduced. That is, by providing the motor housing 20 having a structure excellent in water resistance, the water resistance performance of the electric tool 1 can be enhanced.

(2) The motor housing 20 has a divided structure composed of the first housing member 21 and the second housing member 22, and the notch connected to the mating surfaces of the first housing member 21 and the second housing member 22 is drained. Since the hole portion 24 is configured, the drainage hole portion 24 can be formed together with the wind window 23 when the first housing member 21 and the second housing member 22 are molded, and manufacturing is easy. In addition, when a part of the wind windows 23 is provided in the vicinity of the mating surface of the motor housing 20, the strength of the motor housing 20 may be reduced, but it is connected to the mating surface separately from the wind window 23. By adopting a configuration in which the drain hole 24 is provided, the water resistance of the electric tool 1 can be enhanced while ensuring the strength of the motor housing 20.

(3) By providing the drain hole 24 between the bottom 20a of the motor housing 20 and the motor 10 in the direction of the rotation axis, the water resistance can be improved without increasing the size of the motor housing 20, and the electric tool 1 This is advantageous for downsizing. That is, if the motor housing 20 is elongated in the direction of the rotation shaft 10a and the distance between the motor 10 and the bottom portion 20a of the motor housing 20 is increased, the motor 10 and the substrate 13 can be prevented from being flooded by the drainage from the wind window 23. There is a drawback that the motor housing 20 is enlarged. On the other hand, according to the present embodiment, there is no need to increase the size of the motor housing 20 in order to improve water resistance. Specifically, it is as follows. As shown in FIG. 4, the bottom 20 a side of the motor housing 20 is placed on the lower side by bringing the protective cover 16 and the lower end of the motor housing 20 on the bottom 20 a side into contact with the floor 50 and placing the electric tool 1. When it is disposed at an angle, water that has entered the motor housing 20 gathers on the bottom 20a side. At this time, in the case where the drain hole 24 is not provided, the water that is not discharged from the wind window 23 as shown by the dotted line A in FIG. 4 below the wind window 23 provided closest to the base 5 side. Accumulates on the side of the motor housing 20 and the bottom 20a. As described above, the motor housing 20 is lengthened so that the motor 10, the substrate 13, and the switching element 14 are not positioned within the dotted line A. However, the water resistance effect can be obtained, but the dotted line A shown in FIG. By providing the drainage hole 24 in the motor housing 20, it is possible to improve the water resistance while reducing the size of the motor housing 20.

(4) The drainage holes 24 are arranged so that water can be drained suitably while avoiding the mutual screwing portions of the first housing member 21 and the second housing member 22, and are large in the existing motor housing. It is not necessary to change the shape and is easy to introduce.

(5) Since the drain hole 24 is provided on the base 5 side, when the electric responsive tool 1 is placed on the floor 50 or the work material as shown in FIG. The water that has entered the water is discharged to the outside through the drain hole 24 and is easily discharged every time the operation is completed, and the water is not easily accumulated in the motor housing 20. Further, the state shown in FIG. 4 is a state in which the cutting depth adjusting mechanism 7 is adjusted so that the cutting depth becomes the maximum, but the cutting depth is made shallower and the floor surface 50 or the like as shown in FIG. In the state shown in FIG. 3, the main body 3 rotates counterclockwise with respect to the base 5 in the state shown in FIG. 3, but from the wind window 23 provided between the mating surfaces in the circumferential direction of the motor housing 20, the motor The water that has entered the housing 20 is discharged, and it is difficult for water to accumulate in the motor housing 20 regardless of the state of adjustment of the depth of cut.

Embodiment 2
FIG. 7 is a right side view of the power tool 2 according to Embodiment 2 of the present invention. In the electric power tool 2, unlike the first embodiment shown in FIG. 3 and the like, the mating surfaces of the first housing member 21 and the second housing member 22 are substantially parallel to the bottom surface of the base 5. In this case, the air window 23 of the second housing member 22 on the base 5 side (the air window 23 close to the base 5 side when viewed from the direction of the rotation shaft 10a) also functions as a drain hole. Other points of the present embodiment are the same as those of the first embodiment. According to the present embodiment, when the power tool 2 is placed on the floor 50 or the like as shown in FIG. 4 with the cutting depth being maximized, the wind window 23 of the second housing member 22 on the base 5 side. The water can be drained from the air and water can easily enter from the wind window 23 of the first housing member 21 on the side opposite to the base 5 as compared with the first embodiment. Water is discharged from the wind window 23 and is not easily accumulated in the motor housing 20. Since the portable cutting machine is frequently used in a state in which the cutting depth is adjusted to the maximum, the water resistance of the motor housing 20 is enhanced as compared with the conventional cutting machine.

  The present invention has been described above by taking the embodiment as an example. However, it is understood by those skilled in the art that various modifications can be made to each component and each processing process of the embodiment within the scope of the claims. By the way. Hereinafter, modifications will be described.

  As shown in FIGS. 2 and 5, the drain hole 24 is connected to the bottom 20 a of the motor housing 20, thereby making it difficult for water to accumulate in the motor housing 20. It is good also as a structure provided away from the bottom part 20a. Further, the drain hole 24 may be a notch provided only in one of the first housing member 21 and the second housing member 22. Further, the drain hole 24 may be provided in the bottom 20 a of the motor housing 20. The motor 10 may be a motor with a brush. The drive source is preferably a brushless motor in terms of water resistance. However, according to the structure of the motor housing 20 described in the embodiment, even if the drive source is a motor with a brush, water resistance is improved as compared with the conventional case. It can be improved. The power tool is not limited to the portable cutting machine shown in the embodiment, and may be another type. The electric power tool is not limited to the AC drive type shown in the embodiment, and may be a cordless type in which a battery pack is detachably attached and operates with electric power of the battery pack.

1, 2 Electric tool, 3 Main body, 5 Base, 6 Tilt position adjustment mechanism, 7 Cutting depth adjustment mechanism, 10 Motor, 10a Rotating shaft (output shaft), 10b Bearing, 11 Fan, 12 Deceleration mechanism (Rotation transmission mechanism) , 13 substrate, 14 switching element, 15 circular saw blade, 16 protective cover, 17 magnetic sensor (rotation detector), 20 motor housing, 21 first housing member, 22 second housing member, 23 wind window, 24 drainage Hole, 24a notch, 25 screw fixing hole, 26 screw boss, 27 screw, 28 bearing holding part, 30 gear cover, 40 handle housing, 41 cover side handle part, 42 anti-cover side handle part, 47 trigger switch (operation Switch), 48 control circuit storage, 50 floor

Claims (9)

A motor having a rotating shaft;
A bottomed cylindrical motor housing covering the motor;
A fan capable of rotating integrally with the rotating shaft and generating fan air in the motor housing;
The motor housing is composed of two housing members having a mating surface parallel to the rotating shaft and combined with each other,
Each housing member is provided with a plurality of wind windows for communicating the inside of the motor housing with the outside air,
The electric power tool, wherein the motor housing is provided with a hole connected to the mating surface and positioned between the bottom of the motor housing and the motor in the rotation axis direction.   The housing member and the wind window are molded by molding, and the wind window is located on the bottom side of the motor housing with respect to the rotation axis direction and between the mating surfaces in the circumferential direction of the motor housing. The power tool according to claim 1, wherein the power tool is provided on the power tool.   The electric tool according to claim 2, wherein screwing portions for fixing the housing members to each other are provided on both sides of the wind window in the circumferential direction of the motor housing. The motor is a brushless motor;
A substrate connected to the coil of the brushless motor is provided between the brushless motor and the bottom of the motor housing,
The electric tool according to any one of claims 1 to 3, wherein the hole is provided between the substrate and a bottom portion of the motor housing in the rotation axis direction.   The electric tool according to claim 4, wherein a rotation detection unit that detects a rotation position of the rotation shaft is provided on the substrate.   The electric tool according to any one of claims 1 to 5, wherein the fan is provided on the opposite side of the bottom of the motor housing with respect to the motor. A rotating tool that rotates in response to rotation of the rotating shaft;
A base connected to the motor housing and sliding on the work material;
The electric tool according to any one of claims 1 to 6, wherein the hole is provided on the base side.   The electric tool according to any one of claims 1 to 7, wherein the hole portion is connected to a bottom portion of the motor housing. A motor having a rotating shaft;
A bottomed cylindrical motor housing covering the motor;
A rotating tool that rotates in response to rotation of the rotating shaft;
A base connected to the motor housing and sliding on the work material;
A fan capable of rotating integrally with the rotating shaft and generating fan air in the motor housing;
The motor housing is provided with a plurality of wind windows for communicating the inside of the motor housing with the outside air,
The portable cutting machine, wherein the wind window is provided between the motor and a bottom portion of the motor housing and is closest to the base side in the circumferential direction of the motor housing.

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