JP7220362B2 - Electric tool - Google Patents

Description

The present invention relates to an electric power tool having an output shaft arranged at a predetermined angle with respect to a motor shaft.

In the impact rotary tool, a hammer rotated by a motor output hits the anvil in the rotational direction to generate intermittent rotational impact force on the output shaft to tighten the screw member. A typical impact rotary tool has a configuration in which the rotary shaft of the motor and the tool output shaft are arranged on the same axis, and the grip portion held by the user is angled with respect to the rotary axis.

Since an impact rotary tool with this configuration may be difficult to use in a narrow space, an electric power tool has been developed in which the grip portion is provided substantially parallel to the motor rotation axis and the tool output shaft is angled with respect to the motor rotation axis. . Such a power tool is called an "angle power tool" and uses a long lever switch so that the user can easily operate the switch with fingers while gripping the grip (for example, Patent Documents 1 and 2). reference).

JP 2010-64233 A WO2014/162772

Since the impact rotary tool is used in an assembly factory or the like, the tightening torque of the screw member must be controlled to a value set by the user. In order to control the tightening torque, it is preferable to directly measure the actual tightening torque by providing a torque measuring means on the output shaft. Therefore, it is preferable to provide a configuration for estimating the tightening torque in the angle type power tool.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique for mounting a component for realizing torque control on an angle type power tool.

In order to solve the above problems, an electric power tool according to one aspect of the present invention provides a motor having a motor shaft, an output shaft to which a tip tool is mounted, and an intermittent rotational impact force generated on the output shaft by the motor output. and an impact mechanism. In this power tool, the output shaft is arranged at a predetermined angle with respect to the motor shaft. This power tool includes an impact detection section that detects impact applied to the output shaft by the impact mechanism.

According to the present invention, it is possible to provide a technique for mounting a component for realizing torque control on an angle type electric tool.

1 is a front view of a power tool according to an embodiment; FIG. It is a rear view of the power tool according to the embodiment. It is a left side view of the power tool according to the embodiment. Fig. 2 is a right side view of the power tool according to the embodiment; 1 is a plan view of a power tool according to an embodiment; FIG. It is a bottom view of the power tool according to the embodiment. It is a figure which shows the schematic structure inside an electric power tool. It is a figure which shows the example which arrange|positioned the impact detection part between a motor and a lever switch.

1A is a front view of the power tool 1 according to the embodiment, FIG. 1B is a rear view of the power tool 1, FIG. 1C is a left side view of the power tool 1, and FIG. 1D is a right side view of the power tool 1. 1E is a plan view of the power tool 1, and FIG. 1F is a bottom view of the power tool 1. FIG.

The power tool 1 is a portable power tool with a housing 2 forming an enclosure and may be configured as a portable electric screwdriver. A motor and a power transmission mechanism for transmitting the rotational output of the motor to the output shaft 4 are provided in series in the housing 2 . The power tool 1 of the embodiment is an angle type power tool configured to output a rotational force of a motor in a direction perpendicular to the motor shaft, and the output shaft 4 is at approximately 90° to the motor shaft. are arranged at an angle of The output shaft 4 may be arranged at a predetermined angle other than 90° with respect to the motor shaft, such as 15°, 30°, or 45°.

The housing 2 is composed of a pair of (right and left) half-split housing members that are bisected by a vertical plane crossing the center of the rotational axis of the motor, and the pair of half-split housing members are coupled together by screws. From the front end of the housing 2 is exposed an output shaft 4 on which a tip tool is mounted. A grip portion 5 to be gripped by an operator is formed on the rear end side of the housing 2 , and a long lever switch 3 is provided at an intermediate position in the longitudinal direction of the housing 2 . When the operator pulls the lever switch 3 while gripping the grip portion 5, power is supplied to the motor from the battery pack attached to the lower end of the housing 2, and the output shaft 4 is driven.

A plurality of air hole structures 8 are formed protruding from the surface of the housing 2 on the upper end side of the lever switch 3 in the housing 2 . The air hole structure 8 has an exhaust hole, and may be formed so that air is discharged toward the output shaft 4 side from the exhaust hole. The air hole structure 8 is formed of a pair of walls extending vertically and opposed to each other across the air hole formed in the housing 2, and a connecting portion connecting the tops of the pair of walls. The exhaust hole is kept from being blocked by the user's hand. In the power tool 1, four air hole structures 8 are provided at equal intervals in the circumferential direction as shown. Even if the power tool 1 adopts an exhaust structure other than the air hole structure 8, the air inside the housing 2 is discharged from the upper side of the housing 2 in the direction toward the output shaft 4 side. It is preferable to have a structure that prevents air from hitting the user's hands.

FIG. 2 shows a schematic internal configuration of the power tool 1 . The electric power tool 1 includes a motor 10 having motor shafts 10a and 10b, an output shaft 4 to which a tip tool is attached, a power transmission mechanism 11 for transmitting the rotational output of the motor 10 to the output shaft 4, and the operation of the motor 10. and a control unit 6 for controlling. The control unit 6 supplies electric power of the battery pack attached to the lower end of the housing 2 to the motor 10 according to the operation amount of the lever switch 3 .

The power transmission mechanism 11 has at least an impact mechanism 13 that generates an intermittent rotational impact force on the output shaft 4 by motor output. The motor 10 and impact mechanism 13 are arranged to have the same axis of rotation. As shown in the figure, a part of the elongated lever switch 3 overlaps the motor 10 in the direction perpendicular to the rotation axis.

The impact mechanism 13 has a structure in which the hammer is biased toward the anvil by a spring, and the hammer claw and the anvil claw are engaged in the circumferential direction to transmit the rotation of the hammer to the anvil. When a load torque exceeding a predetermined value is applied to the anvil, the hammer retreats against the biasing force of the spring. The pawl applies a rotational impact to the anvil pawl. With this structure, the impact mechanism 13 generates an intermittent rotational impact force on the output shaft 4 .

In addition to the impact mechanism 13, the power transmission mechanism 11 of the embodiment includes a deceleration mechanism 12 that decelerates the rotation of the motor shaft 10a and transmits it to the impact mechanism 13, and an output shaft that bends the direction of the output axis of the impact mechanism 13 by 90 degrees. It has a direction changing mechanism 14 that transmits to the shaft 4 . The direction changing mechanism 14 has a first bevel tooth portion formed at the tip of the anvil output shaft and a second bevel tooth portion formed at the root of the output shaft 4. The first bevel tooth portion and the second bevel tooth portion The direction of the output axis is changed by meshing.

A rotor and a stator that constitute the inner rotor type motor 10 are individually fixed to the housing 2 . The housing 2 includes stator holding portions 22 and 23 and bearing holding portions 17 and 18 as a structure for assembling the motor 10 to the housing 2 . The stator holding portions 22 and 23 and the bearing holding portions 17 and 18 hold the stator and the bearings 15 and 16 of the motor 10, respectively, by connecting the pair of half-split housing members by screwing or the like.

The stator holding portion 22 is a rib member that protrudes from the inner peripheral surface of the housing 2 and holds the outer periphery of one end side of the stator, here, the front end side of the stator. The stator holding portion 22 is composed of rib members formed respectively on the pair of half-split housing members, and the plurality of rib members sandwich and fix the outer periphery of the stator on the front end side.

The stator holding portion 23 is a rib member protruding from the inner peripheral surface of the housing 2 and holding the outer periphery of the other end side of the stator, here, the rear end side of the stator. The stator holding portion 23 is composed of rib members formed on each of the pair of half-split housing members.

The bearing holding portion 17 is a rib member that protrudes from the inner peripheral surface of the housing 2 and holds the outer periphery of the bearing 15 that supports the motor shaft 10a on the front end side. The bearing holding portion 17 is composed of rib members respectively formed on the pair of half-split housing members, and the outer periphery of the bearing 15 is sandwiched and fixed by the plurality of rib members.

The bearing holding portion 18 is a rib member that protrudes from the inner peripheral surface of the housing 2 and holds the outer periphery of the bearing 16 that supports the motor shaft 10b on the rear end side. The bearing holding portion 18 is composed of rib members formed respectively on the pair of half-split housing members, and the outer periphery of the bearing 16 is sandwiched and fixed by the plurality of rib members.

The power tool 1 of the embodiment includes an impact detection section 30 that detects impact applied to the output shaft 4 by the impact mechanism 13 in order to realize torque control by the control section 6 . The impact detection unit 30 detects the impact caused by the impact mechanism 13 and supplies the detection result to the control unit 6 through the electric wire 7 . The control unit 6 performs seating determination of the screw member from the detection result of the impact detection unit 30, counts the number of impact impacts, and the number of impact impacts after the seating determination reaches a number corresponding to the torque value set by the user. Then, the power supply to the motor 10 is automatically stopped to complete the tightening of the screw member.

The impact detection section 30 may include a shock sensor that detects impact impact, and an amplifier that amplifies the output of the shock sensor and supplies it to the control section 6 . For example, the shock sensor is a piezoelectric shock sensor that outputs a voltage signal corresponding to the impact.

Ideally, the impact detection unit 30 is arranged near the impact mechanism 13 in order to detect impact with high sensitivity. As shown in FIG. 2, the impact mechanism 13 is arranged on the front side in the housing 2, and if it is attempted to arrange the impact detection section 30 near the impact mechanism 13, the front side of the housing 2 must be placed in order to secure the arrangement space. result in a larger diameter. Since the power tool 1 is an angle type power tool intended to be inserted into a narrow space to work, it is desirable to avoid increasing the diameter of the front side.

Therefore, in the power tool 1 of the embodiment, the impact detection section 30 is arranged on the rear end side of the motor 10 . Since the rear end side of the motor 10 can easily secure an arrangement space and is originally held by an operator, the demand for a smaller diameter is relatively low. Although the impact detector 30 is slightly separated from the impact mechanism 13 compared to when it is arranged on the front side of the housing 2, there is an advantage that the front side of the housing 2 does not have to be thickened.

The board on which the impact detection section 30 is mounted is held by a board holding section 20 projecting from the inner peripheral surface of the housing 2 on the rear end side of the motor 10 . Since the substrate holding portion 20 is formed on the inner peripheral surface of the housing 2 , the impact caused by the impact mechanism 13 is detected by the impact detecting portion 30 via the substrate holding portion 20 from the housing 2 .

The impact of the impact mechanism 13 is also transmitted to the motor 10 connected to the impact mechanism 13 . Although the housing 2 is made of a resin material, the motor shafts 10a and 10b are made of a metal material. Therefore, the present inventor provides the substrate holder 20 in the vicinity of the bearing holder 18 that holds the bearing 16 of the motor shaft 10b so that the impact detector 30 can efficiently detect the impact transmitted to the motor 10. I decided to This allows the impact detection section 30 to effectively detect the impact transmitted via the motor 10 . Furthermore, in the embodiment, the bearing holding portion 18 and the substrate holding portion 20 are connected by the connecting rib 21 to improve the transmission efficiency of the impact impact from the bearing holding portion 18 to the substrate holding portion 20 .

A detection result by the impact detection unit 30 is supplied to the control unit 6 through the electric wire 7 . As described above, the control unit 6 may perform torque control for automatically stopping the rotation of the motor 10 based on the number of impact impacts after the screw member is seated.

The present invention has been described above based on the embodiments. It should be understood by those skilled in the art that this embodiment is an example, and that various modifications can be made to the combination of each component or each treatment process, and such modifications are also within the scope of the present invention. .

In the embodiment, the impact detection section 30 is arranged on the rear end side of the motor 10, but in order to effectively utilize the empty space between the lever switch 3 and the motor 10 and bring the arrangement position closer to the impact mechanism 13, , the impact detector 30 may be arranged between the motor 10 and the lever switch 3 .

FIG. 3A shows an example in which the impact detector 30 is arranged between the motor 10 and the lever switch 3. FIG. The substrate holding portion 20 a holds the substrate on which the impact detection portion 30 is mounted in a direction parallel to the rotational axis of the motor 10 . A space between the motor 10 and the lever switch 3 can be relatively easily secured in the direction of the rotation axis, and the empty space can be effectively used by providing the mounting substrate in a direction parallel to the rotation axis.

FIG. 3(b) shows another example in which the impact detector 30 is arranged between the motor 10 and the lever switch 3. As shown in FIG. The substrate holding portion 20b holds the substrate on which the impact detection portion 30 is mounted in a direction orthogonal to the rotational axis of the motor 10. As shown in FIG. By arranging the mounting board in a direction orthogonal to the rotation axis, there is an advantage that the wiring of the electric wire 7 is facilitated.

A summary of aspects of the invention follows.
An electric power tool (1) according to one aspect of the present invention comprises a motor (10) having motor shafts (10a, 10b), an output shaft (4) to which a tip tool is mounted, and a motor output to the output shaft (4). an impact mechanism (13) for generating an intermittent rotational impact force. The output shaft (4) is arranged at a predetermined angle with respect to the motor shafts (10a, 10b), and the power tool (1) includes an impact detection section ( 30).

The impact detector (30) may be arranged on the rear end side of the motor (10). A first holding portion (18) for holding a bearing (16) supporting a rear end motor shaft (10b) of a motor (10) and an impact detection portion (30) are provided on the inner peripheral surface of the housing (2). A second holding portion (20) for holding the mounted substrate is formed, and the first holding portion and the second holding portion may be connected by a rib (21).

The motor (10) and the impact mechanism (13) are arranged so as to have the same rotation axis, and the lever switch (3) is provided at a position overlapping the motor (10) in the direction perpendicular to the rotation axis. 30) may be placed between the motor and the lever switch. At this time, the substrate may be provided in a direction parallel to the rotation axis, or may be provided in a direction orthogonal to the rotation axis.

DESCRIPTION OF SYMBOLS 1... Electric tool, 2... Housing, 3... Lever switch, 4... Output shaft, 5... Grip part, 6... Control part, 7... Electric wire, 8... Air hole structure 10 Motor 10a, 10b Motor shaft 11 Power transmission mechanism 12 Reduction mechanism 13 Impact mechanism 14 Direction changing mechanism 15, 16... Bearings 17, 18... Bearing holding portion 20... Board holding portion 21... Connection rib 22, 23... Stator holding portion 30... Impact detecting portion .

Claims (5)

a motor having a motor shaft;
an output shaft to which the tip tool is attached;
an impact mechanism that generates an intermittent rotational impact force on the output shaft by a motor output, wherein the output shaft is arranged at a predetermined angle with respect to the motor shaft,
An impact detection unit for detecting impact applied to the output shaft by the impact mechanism is provided, the impact detection unit is arranged in a grip portion held by an operator on the rear end side of the motor,
On the inner peripheral surface of the housing,
a first holding portion that holds a bearing that supports the rear end side motor shaft of the motor;
a second holding portion for holding the board on which the impact detection portion is mounted;
the motor and the impact mechanism are arranged to have the same axis of rotation;
The lever switch is provided at a position overlapping the motor in the direction perpendicular to the rotation axis,
the board on which the impact detection unit is mounted is arranged between the motor and the lever switch;
A power tool characterized by: The impact mechanism is arranged on the front end side of the motor,
The power tool according to claim 1, characterized in that: The first holding portion and the second holding portion are connected by a rib,
The power tool according to claim 1 or 2, characterized in that: wherein the substrate is oriented parallel to the axis of rotation;
The power tool according to claim 1 , characterized in that: wherein the substrate is oriented perpendicular to the axis of rotation;
The power tool according to claim 1 , characterized in that:

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