JP6887118B2 - Electric tool - Google Patents

Description

The present invention relates to a power tool including a motor.

Patent Document 1 discloses an electric tool in which a circular grindstone is connected to a rotating shaft of a motor. This power tool includes a rotation position detecting means composed of a sensor magnet attached to the rear end of the rotation shaft of the motor and a plurality of Hall ICs mounted on a circuit board.

International Publication No. 2016/2543

In electric tools such as impact rotary tools, control is performed to estimate the tightening torque from the rotation angle of the motor. In order to improve the estimation accuracy of the tightening torque, the power tool is provided with a rotation detection unit that detects the rotation angle of the motor with high accuracy. In order for the rotation detection unit to exhibit stable rotation angle detection performance, it is preferable to form a dustproof structure that prevents dust and the like from entering the space provided with the rotation detection unit. It should be noted that not only the rotation detection unit but also when other types of parts are arranged in the space, it is not preferable that dust or the like adheres to the parts. Therefore, it is possible to form a dustproof structure in which dust or the like does not easily enter the space. desired.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a dustproof structure for protecting mounted parts from dust and the like.

In order to solve the above problems, the power tool of a certain aspect of the present invention has a housing and a motor shaft that form an outer shell of the power tool by connecting a pair of first housing members and a second housing member. A bearing holder that is formed so as to project from the inner peripheral surface of the housing and holds the bearing that supports the motor shaft, a transmission mechanism that transmits the rotational output of the motor to the tip tool, a bearing holder and the housing. It includes parts arranged in a space formed between the rear end and the rear end. The wiring of the parts is accommodated in the space on the side of the first housing member and is drawn out of the space through the opening. The second housing member has a dustproof portion that enters the first housing member and narrows the communication port between the space where the parts are arranged and the opening.

According to the present invention, it is possible to provide a dustproof structure that protects mounted parts from dust and the like.

It is a figure which shows the outline of the power tool which concerns on embodiment. It is a figure which shows the perspective structure of the 1st housing member. It is a figure which shows the side surface of the 1st housing member. It is a figure which shows the perspective structure of the 2nd housing member. It is a figure which shows the example of the cross section of the rear end of a housing.

FIG. 1 shows an outline of a power tool according to an embodiment of the present invention. The power tool 1 includes a housing 2, and a motor 3 is housed in the housing 2. The motor 3 is configured as a built-in motor that functions by assembling a stator and a rotor integrated with a motor shaft to the housing 2, and does not have a motor case, which contributes to miniaturization and weight reduction of the electric tool 1. Hereinafter, the motor shaft on the front side of the motor 3 will be referred to as "motor shaft 4a", and the motor shaft on the rear end side will be referred to as "motor shaft 4b".

The bearing holding portion 14a is a rib member formed so as to project radially from the inner peripheral surface of the housing 2, and holds the bearing 12a that supports the motor shaft 4a. The bearing holding portion 14a holds the radial direction and the axial direction of the outer ring of the bearing 12a. Here, the bearing holding portion 14a holds the front end face side of the bearing 12a in the axial direction, and the rear end face side of the bearing 12a is held by the pressing member 9a.

The bearing holding portion 14b is a rib member formed so as to project radially from the inner peripheral surface of the housing 2, and holds the bearing 12b that supports the motor shaft 4b. The bearing holding portion 14b holds the radial direction and the axial direction of the outer ring of the bearing 12b. Here, the bearing holding portion 14b holds the rear end face side of the bearing 12b in the axial direction, and the front end face side of the bearing 12b is held by the pressing member 9b. A space S is formed between the bearing holding portion 14b and the rear end 23 of the housing 2, and various parts such as the rotation detecting portion 10 and the LED 11 are arranged in this space S.

The drive block 5 includes a transmission mechanism that transmits the rotational output of the motor 3 to the tip tool. Specifically, the drive block 5 includes a power transmission mechanism that transmits the rotational output of the motor shaft 4a to the output shaft 6, and the power transmission mechanism has a planetary gear reduction mechanism that meshes with a pinion gear attached to the motor shaft 4a. Good. When the power tool 1 is an impact rotary tool, the power transmission mechanism includes an impact mechanism that generates an intermittent rotary impact force on the output shaft 6. A chuck mechanism 7 is connected to the output shaft 6 so that tip tools such as a drill and a screwdriver can be attached and detached. An operation switch 8 operated by an operator is provided on the grip portion of the housing 2. When the operator pulls the operation switch 8, the rotor in the motor 3 rotates, and the output shaft 6 drives the tip tool.

The motor 3 is an inner rotor type brushless motor, and a rotor having a plurality of permanent magnets rotates inside the stator. The rotor and the stator, which are the components of the motor 3, are individually and independently fixed to the housing 2. The housing 2 has a pair of (left and right) half-split housing members that are bisected by a vertical plane that crosses the center of rotation axis of the power tool 1. By connecting the pair of first housing members and the second housing member, the housing 2 constituting the outer shell of the power tool 1 is realized.

Behind the motor 3, a rotation detection unit 10 for detecting the rotation angle of the motor is provided. The rotation detection unit 10 includes a rotating body attached to the end of the motor shaft 4b, and a position detecting unit that outputs a rotation position signal according to the rotation position of the rotating body. The position detection unit may be a sensor provided on a sensor substrate arranged so as to face the rotating body in the axial direction. The rotation detection unit 10 may be a magnetic encoder or an optical encoder.

When the rotation detection unit 10 is a magnetic encoder, the rotating body has a magnet, and the position detection unit has a magnetic sensor that detects a change in magnetic force. In order to improve the detection accuracy of the motor rotation angle, the distance between the rotating body and the position detection unit is set narrow, for example, the distance between the two is about 2 mm. When the rotation detection unit 10 is an optical encoder, the rotating body is a rotating disk formed with slits that block / transmit light, and the position detection unit has a light receiving element such as a photodiode. The rotation detection unit 10 may be an encoder of any type, and the position detection unit transmits a rotation position signal corresponding to the rotation position of the rotating body to a control unit (not shown) that controls the motor rotation through a signal line. Output.

The LED 11 is, for example, a light emitting body that lights up when the tightening of the screw member by the power tool 1 is completed. A window 11a is provided above the rear end of the housing 2, and the operator recognizes that the tightening of the screw member is completed by confirming the lighting from the window 11a.

In the power tool 1 of the embodiment, the space S between the bearing holding portion 14b and the rear end 23 of the housing 2 is formed by combining the rear end of the first housing member and the rear end of the second housing member. , Various parts such as the rotation detection unit 10 and the LED 11 are arranged. Since the rotation detection unit 10 has a sensor component, it is preferable that a dustproof structure is formed so that dust and the like do not enter the space S.

FIG. 2 shows a perspective configuration of the first housing member 2a, and FIG. 3 shows a side surface of the first housing member 2a. Note that FIGS. 2 and 3 show only the rear end side of the first housing member 2a, and the other drawings are omitted. The bearing holding portion 14b is a rib member provided on the inner peripheral surface of the first housing member 2a, and holds the radial direction and the axial direction of the outer ring of the bearing 12b.

The rotating body 20 constitutes one component in the magnetic encoder which is the rotation detecting unit 10, and has a magnet and a mounting component for fixing the magnet. The mounting component is formed with a recess for fitting the magnet, and the magnet may be fitted and fixed in the recess. The sensor board 16 is held by a sensor board holding portion 13 provided at the rear end portion of the first housing member 2a. The sensor substrate 16 is arranged to face the rotating body 20 in the axial direction, specifically, the magnet, and mounts a magnetic sensor 15 which is a detection unit for detecting the rotation angle of the motor 3. The wiring 16a includes a power line for supplying electric power to the magnetic sensor 15 and a signal line for outputting the detection value of the magnetic sensor 15, and is connected to the sensor board 16.

The LED 11 is a light emitting element and is turned on when the tightening of the screw member is completed. The LED 11 is held by the LED holding portion 19 provided at the rear end portion of the first housing member 2a. The wiring 11b includes a power line for supplying electric power to the LED 11 and a signal line for supplying a lighting signal, and is connected to the LED 11. The wiring 16a of the sensor board 16 and the wiring 11b of the LED 11 are housed in the space S on the side of the first housing member 2a. The wirings 16a and 11b are drawn out of the space S from the opening 18 via the communication port 25.

FIG. 4 shows a perspective configuration of the second housing member 2b. FIG. 4 shows only the rear end side of the second housing member 2b, and the other illustrations are omitted. The second housing member 2b has an LED holding portion 19 for holding the LED 11 and a sensor substrate holding portion 13 for holding the sensor substrate 16. In this way, a pair of sensor substrate holding portions 13 and LED holding portions 19 are formed in the first housing member 2a and the second housing member 2b.

The second housing member 2b has a dustproof portion 21 that enters the first housing member 2a and narrows the communication port 25 between the space S in which the parts are arranged and the opening 18. The dustproof portion 21 is a plate-shaped member protruding from the cracked surface of the second housing member 2b, and is formed in a shape that closes a part of the communication port 25 of the first housing member 2a. Here, the cracked surface is an end surface that abuts on the first housing member 2a.

Further, the second housing member 2b has a wiring holding portion 22 that enters the first housing member 2a and presses the wiring 11b to the inner peripheral surface side of the first housing member 2a. The dustproof portion 21 also has a function of pressing the wirings 11b and 16a to the inner peripheral surface side of the first housing member 2a, similarly to the wiring pressing portion 22. In the embodiment, the space in which the LED 11 is arranged is sealed by the window 11a, but when an air hole is formed in this space, the wiring holding portion 22 is the arrangement space of the air hole and the rotation detection unit 10. It also functions as a dustproof part that narrows the communication port between and. By entering the wiring holding portion 22 into the first housing member 2a, a structure is realized in which dust and the like are less likely to enter the arrangement space of the rotation detecting portion 10 from the air holes.

FIG. 5A shows an example of a cross section of the rear end of the housing 2. Note that FIG. 5A shows a state in which the first housing member 2a and the second housing member 2b are connected and notched along the line AA shown in FIG.

As shown in FIG. 5A, the dustproof unit 21 enters the communication port 25 and closes a part of the communication port 25. As a result, a dustproof structure is realized in which dust does not easily enter the space S from the opening 18. Further, the dustproof portion 21 also has a role of pressing the wirings 11b and 16a against the inner peripheral surface side of the first housing member 2a to limit the movement of the wirings in the space S.

FIG. 5B shows another example of the cross section of the rear end of the housing 2. Note that FIG. 5B shows a state in which the first housing member 2a and the second housing member 2b are connected and notched along the line BB shown in FIG.

As shown in FIG. 5B, the wiring holding portion 22 presses the wiring 11b to the inner peripheral surface side of the first housing member 2a. In the embodiment, the dustproof portion 21 and the wiring holding portion 22 press the wiring to the inner peripheral surface side of the first housing member 2a at two places to fix the wiring position in the space S. By pressing the wiring at two points, floating of the wiring is prevented, and for example, the occurrence of a situation in which the wiring moves in the direction of the rotation axis and impairs the rotation angle detection function by the rotation detection unit 10 is avoided.

The present invention has been described above based on the embodiments. This embodiment is an example, and it will be understood by those skilled in the art that various modifications are possible for each of these components or combinations of each processing process, and that such modifications are also within the scope of the present invention. ..

The outline of the aspect of the present invention is as follows.
The power tool (1) according to an aspect of the present invention is a housing (1) that constitutes an outer shell of the power tool (1) by connecting a pair of first housing members (2a) and a second housing member (2b). 2), a motor (3) having a motor shaft (4b), and a bearing (12b) formed so as to project from the inner peripheral surface of the housing (2) to support the motor shaft (4b). A space S formed between the holding portion (14b), the transmission mechanism (5) that transmits the rotational output of the motor (3) to the tip tool, and the rear end of the bearing holding portion (14b) and the housing (2). The parts (15, 11) arranged in the above are provided, and the wirings (11b, 16a) of the parts are accommodated in the space S on the first housing member side and pulled out from the opening (18) to the outside of the space. Therefore, the second housing member (2b) enters the first housing member (2a) and narrows the communication port (25) between the space S in which the parts are arranged and the opening (18). 21).

The dustproof portion (21) is a plate-shaped member protruding from the end surface of the second housing member (2b), and may be formed in a shape that closes a part of the communication port (25) of the first housing member (2a). .. The dustproof portion (21) preferably presses the wiring (11b, 16a) on the inner peripheral surface side of the first housing member (2a). The second housing member (2b) preferably further includes a wiring holding portion (22) that presses the wiring (11b) on the inner peripheral surface side of the first housing member (2a).

1 ... Electric tool, 2 ... Housing, 2a ... 1st housing member, 2b ... 2nd housing member, 3 ... Motor, 4a, 4b ... Motor shaft, 5 ... Drive block, 10 ... Rotation detection unit, 11 ... LED, 11b ... Wiring, 12a, 12b ... Bearing, 13 ... Sensor substrate holding part, 14a, 14b ... Bearing holding part, 15 ... Magnetic sensor, 16 ... Sensor board, 16a ... Wiring, 18 ... Opening, 19 ... LED holding part, 20 ... Rotating body, 21 ... Dustproof part, 22.・ ・ Bearing holding part, 25 ・ ・ ・ Communication port.

Claims (4)

It ’s a power tool,
By connecting the pair of first housing members and the second housing member, the housing constituting the outer shell of the power tool and the housing
A motor having a first motor shaft on the front side and a second motor shaft on the rear side,
A first bearing holding portion that is formed so as to project from the inner peripheral surface of the housing and holds the first bearing that supports the first motor shaft.
A second bearing holding portion that is formed so as to project from the inner peripheral surface of the housing and holds the second bearing that supports the second motor shaft.
A transmission mechanism that transmits the rotational output of the first motor shaft to the tip tool,
A component arranged in a space formed between the second bearing holding portion and the rear end of the housing by combining the first housing member and the second housing member is provided, and wiring of the component is provided. , the is accommodated in the space of the first housing member side of the space, from the second opening formed in the bearing holding portion, there is drawn to the outside of the first housing member side of the space,
The second housing member has a dustproof portion that enters the first housing member and narrows a communication port between a space on the side of the first housing member on which the component is arranged and an opening.
A power tool characterized by that. The dustproof portion is a plate-shaped member protruding from the end surface of the second housing member, and is formed in a shape that closes a part of the communication port of the first housing member.
The power tool according to claim 1. The dustproof portion presses the wiring to the inner peripheral surface side of the first housing member.
The power tool according to claim 1 or 2. The second housing member further includes a wiring holding portion that presses the wiring on the inner peripheral surface side of the first housing member.
The power tool according to any one of claims 1 to 3, wherein the power tool is characterized in that.

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