JP5013911B2 - Electric tool - Google Patents

Description

  The present invention relates to an electric tool using a motor as a drive source, and more particularly to an electric tool using a plurality of electric motors as a drive power source.

As electric tools using a motor as a drive source, electric tools having various structures are known. For example, Japanese Patent Laid-Open No. 2006-142392 (Patent Document 1) discloses an electric nail driver (electric tool) that uses a motor as a drive source for driving a movable body that drives (blows) a nail into a workpiece. It is disclosed. The electric nail driver disclosed in Patent Document 1 has a drive roller that is driven to rotate by a motor and a fixed roller that is fixedly supported as a drive mechanism that drives a plunger (movable body) for driving a nail. The mechanism is used. In this electric nail driver, when the plunger is sandwiched between the driving roller and the fixed roller, the plunger moves in the direction of driving the nail into the workpiece by the rotational force of the driving roller.
JP 2006-142392 A

In the drive mechanism described in Patent Document 1, a plunger (movable body) sandwiched between a drive roller driven by a motor and a fixed roller fixedly supported is moved by the rotational force of the drive roller. Yes. That is, the driving force applied to the plunger is determined by the characteristics of the motor that drives the driving roller. For this reason, there is a limit in increasing the driving force applied to the plunger.
Here, in such a drive mechanism, as a method of increasing the driving force of the plunger, a method of driving each roller sandwiching the plunger by a separate motor can be considered. However, when each of the rollers that sandwich the plunger is driven by a separate motor, it is necessary to synchronize the rotation speed of each motor. In order to synchronize the rotation speeds of a plurality of motors, a complicated and expensive control device is required.
The present invention has been made in view of such a point, and an object of the present invention is to provide a technique for driving a movable body of an electric tool jointly by a plurality of motors easily and inexpensively.

The preferable form of the electric tool of the present invention includes a movable body, a plurality of motors that drive the movable body together, and a battery for supplying power to the plurality of motors. Then, the workpiece is processed by driving the movable body. As the movable body and the driving mode of the movable body, a movable body and a movable mode corresponding to the processing method of the workpiece are used. For example, in an electric driving tool, a driver (or a driver support base that supports the driver) that can move a driving material such as a nail into a workpiece is used. As the number of motors that drive the movable body jointly, an appropriate number of 2 or more can be selected.
The mode in which the movable body is driven jointly by the plurality of motors includes, for example, a mode in which one movable body is driven by the rotational force of the plurality of motors. Typically, a mode in which the movable body is driven by bringing the movable body into contact with a plurality of rollers that are rotationally driven by each of the plurality of motors and transmitting the rotational force of each motor to the movable body via each roller is supported. To do. By driving the movable body jointly with a plurality of motors, the driving force of the movable body can be increased.
When the movable body is driven jointly by a plurality of motors, it is necessary to synchronize the rotation speeds of the plurality of motors. In a preferred form of the electric power tool of the present invention, the plurality of motors that jointly drive the movable body are configured such that the number of rotations changes according to a change in load. The “configuration in which the rotational speed of the motor changes according to the change in the load” includes an aspect using a motor having a characteristic that the rotational speed changes according to the change in the load, The mode which controls a motor so that rotation speed changes is included. Synchronizing the rotational speeds of multiple motors without using a complex and effective synchronization device by configuring the rotational speeds of each of the multiple motors that drive the movable body together according to the respective loads Can be made.

In another preferred aspect of the present invention, a motor selected from a universal motor, a DC magnet motor, and a DC brushless motor is used as the plurality of motors that jointly drive the movable body. As the plurality of motors, the same type of motor is preferably used, but different types of motors may be used.
A plurality of motors are connected to a constant voltage power source. The constant voltage power source includes a voltage adjustment circuit and a battery for adjusting the voltage of the battery to a set voltage. A mode in which a constant voltage power supply is connected to a plurality of motors includes a mode in which a plurality of motors are connected in parallel to a common output terminal of a voltage adjustment circuit that adjusts the battery voltage to a set voltage, The aspect which connects the motor which comprises a some motor to each of the some output terminal of the voltage adjustment circuit to adjust, and the aspect which connects a some motor in parallel to the terminal of a battery are included.
When a motor such as a universal motor, a DC magnet motor, or a DC brushless motor is connected to a constant voltage power supply, the number of rotations changes according to a change in load. Also, when multiple motors that drive the movable body jointly are connected to the constant voltage power supply in parallel, the rotational speed of the motor with the higher rotational speed is the rotational speed of the motor with the lower rotational speed. In other words, the rotation speeds of the plurality of motors are synchronized with the rotation speeds of the motors having a low rotation speed.
In this aspect of the present invention, the plurality of rotation speeds are automatically synchronized only by connecting the plurality of motors to the constant voltage power source. Thereby, the rotation speeds of a plurality of motors can be more easily and inexpensively synchronized.

When starting a plurality of motors, a starting current flows through each motor. For this reason, if a plurality of motors are activated simultaneously, the voltage of the battery provided as a power source may be greatly reduced. Such a voltage drop of the battery due to the starting current of the motor causes an undesirable state. Therefore, in another aspect of the present invention, there is provided a battery voltage drop suppression device that suppresses battery voltage drop due to start-up currents of a plurality of motors. Various methods can be used as a battery voltage drop suppression method by the battery voltage drop suppression device.
In one technique, when starting up a plurality of motors, the voltage applied to the motors is gradually increased. For example, if you have a voltage adjustment circuit that inputs battery voltage and outputs voltage pulses from a common output terminal, the duty ratio of the voltage pulse output from the output terminal of the voltage adjustment circuit (ON period / OFF Period). The mode in which the voltage is gradually increased includes a mode in which the voltage is changed in at least two stages.
In another method, when starting a plurality of motors, the time point at which a voltage is applied to the motors is shifted. For example, if you have a voltage adjustment circuit that inputs battery voltage and outputs voltage pulses from a common output terminal, provide a start switch between the output terminal of the voltage adjustment circuit and each of the multiple motors. , Shift the time to turn on each start switch. Alternatively, in the case of having a voltage adjustment circuit that inputs battery voltage and outputs voltage pulses from a plurality of output terminals, each motor constituting the plurality of motors is connected to each output terminal of the voltage adjustment circuit. . And the time which outputs a voltage pulse from each output terminal of a voltage adjustment circuit is shifted. A mode in which the time point at which the voltage is applied to the motor is shifted includes a mode in which the motors constituting the plurality of motors are divided into groups and the time point at which the voltage is applied is shifted for each group.
In another method, when starting up a plurality of motors, the voltage applied to the motor is gradually increased and the time point at which the voltage is applied to the motor is shifted. For example, when a voltage adjustment circuit that inputs battery voltage and outputs voltage pulses from a plurality of output terminals is provided, each of the motors constituting the plurality of motors is connected to each output terminal of the voltage adjustment circuit. . Then, the duty ratio of the voltage pulse output from each output terminal of the voltage adjustment circuit is sequentially increased, and the output time point of the voltage pulse output from each output terminal is shifted. In this case, the output start time point of the voltage pulse output from each output terminal may be shifted by at least several pulses. Alternatively, when a voltage adjustment circuit that inputs battery voltage and outputs voltage pulses from a common output terminal is provided, a start switch is provided between the output terminal of the voltage adjustment circuit and each of the plurality of motors. . Then, the duty ratio of the voltage pulse output from the common output terminal of the voltage adjustment circuit is sequentially increased, and the time at which each start switch is turned on is shifted. When the third method is used, a plurality of motors can be started in a short time while suppressing a decrease in battery voltage.

In yet another aspect of the present invention, the movable body is movable in a direction in which a driving material such as a nail is driven into the workpiece. Moreover, the 1st and 2nd motor is used as a some motor. Further, there are provided first and second rotating bodies that are arranged at intervals and are driven to rotate by first and second motors, respectively. In addition, a pressing member is provided that presses the movable body toward the first and second rotating bodies from a direction that intersects the moving direction of the movable body. Further, the movable body extends along the moving direction of the movable body and extends toward the front in the pressing direction of the pressing member so that the mutual distance becomes narrower. When the movable body is pressed by the pressing member, First and second contact surfaces that are in contact with the first and second rotating bodies are provided.
The “first and second contact surfaces” can be formed in various shapes, but typically, a cross-sectional shape in a direction intersecting the moving direction of the movable body is formed in a V shape or a trapezoid. The “contact” mode typically corresponds to a mode in which the first and second contact surfaces are in contact with the outer peripheral surfaces of the first and second rotating bodies, but the first and second rotations. The aspect in which the side surface of a body contacts is also included. This aspect only needs to have a configuration in which the movable body is driven by at least the first and second rotating bodies that are rotationally driven by the first and second drive motors, and further for driving the movable body. The use of other rotating bodies is not excluded.
In this aspect, when the movable body is pressed against the first and second rotating bodies by the pressing member, the first and second contact surfaces of the movable body are located between the first rotating body and the second rotating body. It becomes a state of biting (wedge effect). As a result, the rotational forces of the first and second motors are efficiently transmitted to the movable body via the first and first rotating bodies. In addition to this, the rotational speeds of the first and second motors can be synchronized by the above-described configuration. Therefore, a sufficient driving force can be applied to the movable body easily and inexpensively.

  According to the present invention, a movable body for performing a processing operation can be easily and inexpensively driven by a plurality of motors together, and the driving force of the movable body can be increased.

(First embodiment of the present invention)
The first embodiment of the present invention will be described in detail with reference to FIGS. This embodiment is configured as an electric nail driver which is an example of a driving tool. FIG. 1 shows the entire electric nail driver according to the present embodiment. FIG. 2 shows an X-ray arrow view of FIG. FIG. 3 is a perspective view of the main part of the electric nail driver. 4 is a cross-sectional view taken along line YY of FIG. FIG. 5 shows a pressing mechanism for pressing the driver support base against the flywheel. FIG. 6 shows a driver support base and a driver.

As shown in FIG. 1, an electric nail driver (hereinafter simply referred to as “nailer”) 100 includes a main body 101 that forms an outer shell of the nail driver 100, and an operator It is mainly composed of a handle portion 103 for gripping and a magazine 105 loaded with nails n as driving materials to be driven into a workpiece. The handle portion 103 is integrally provided so as to protrude sideways from the side portion of the main body portion 101. A battery pack 107 in which a rechargeable battery serving as a power source for the drive motors 113 </ b> A and 113 </ b> B is housed is attached to an end portion of the handle portion 103.
FIG. 1 shows a state in which the front end portion of the main body 101 is directed to the workpiece. For this reason, the downward direction in FIG. 1 is the driving direction of the nail n (the long axis direction of the main body 101), and the driving direction of the nail n by the driver 121.

A driver guide 111 that constitutes a nail injection port is disposed at the tip of the main body 101 (downward in FIG. 1). The magazine 105 is mounted so as to span between the front end portion of the main body 101 and the end portion of the handle portion 103, and the front end portion on the nail supply side is connected to the driver guide 111.
The magazine 105 is provided with a pusher plate 105a for pushing the nail n in the supply direction (leftward in FIG. 1). The pusher plate 105a causes the nail to cross the driving direction in the driving hole 111a of the driver guide 111. Are supplied one by one. The driving hole 111a is penetrated in the driving direction of the nail n. For convenience of explanation, the driver guide 111 side (lower side in FIG. 1) is referred to as the front, and the opposite side is referred to as the rear.

The main body 101 is made of a resin formed in a substantially cylindrical shape and mainly includes a main body housing 110 having a split structure. Inside the main body housing 110 are housed two drive motors 113A and 113B and a nail driving mechanism 117 that is rotationally driven by the drive motors 113A and 113B. The drive motors 113A and 113B correspond to the “first and second motors” in the present invention.
The nail driving mechanism 117 includes a driver 121 that moves in the driving direction of the nail n and hits the nail n, a drive mechanism 131 that moves the driver 121 by the rotational force of the drive motors 113A and 113B, and a driver 121 after the nail driving. A return mechanism 191 for returning to the standby position (initial position) before the hitting operation is mainly configured. The standby position refers to a position where the driver 121 is returned by the return mechanism 191 and abuts against the stopper 197 at the rearmost position (the upper position in FIG. 1) farthest from the driver guide 111.

A driver support base 123 made of a metal rod-like material that is movable in a direction parallel to the driving direction via a slide support mechanism (not shown) for convenience is provided at a substantially central portion of the main body housing 110. A driver 121 is joined to the tip of the driver support base 123 in the driving direction (downward in FIG. 1).
The driver 121 is formed of a metal rod-like material having a substantially rectangular cross section that is thinner than the driver support base 123. The driver 121 extends toward the driver guide 111, and the tip thereof reaches the entrance (upper opening in FIG. 1) of the driving hole 111a. The driver 121 and the driver support base 123 correspond to the “movable body” of the present invention, and FIG.

  The driver support base 123 has a power transmission portion 124 having a V-shaped cross section. The power transmission unit 124 is provided over the entire longitudinal direction (movement direction) of the driver support base 123. The power transmission unit 124 has power transmission surfaces 124a and 124a extending in an inclined manner so that the distance between the left and right sides in the driving direction (movement direction) becomes narrower toward the front in the pressing direction of a pressing roller 160 described later. Is provided. That is, the left and right power transmission surfaces 124a and 124a are arranged so as to form a V shape, thereby constituting a power transmission portion 124 having a V-shaped cross section. The left and right power transmission surfaces 124a and 124a correspond to the “first and second contact surfaces” in the present invention.

  As shown in FIG. 2, the drive mechanism 131 includes a pair of left and right flywheels 133 </ b> A and 133 </ b> B that are separately rotated at high speed by drive motors 113 </ b> A and 113 </ b> B, and a driver support base 123. It is mainly composed of a pressing roller 163 that presses against the flywheels 133A and 133B. The pair of flywheels 133A and 133B corresponds to the “first and second rotating bodies” of the present invention, and the pressing roller 163 corresponds to the “pressing member” of the present invention.

  As shown in FIG. 4, the pair of flywheels 133 </ b> A and 133 </ b> B is formed in a cylindrical body shape whose outer peripheral surface is parallel to the rotation axis. And it arrange | positions symmetrically regarding the straight line of the direction which cross | intersects the moving direction of the driver support stand 123 so that a mutual rotation axis may form V shape. That is, the pair of flywheels 133 </ b> A and 133 </ b> B has a V-shaped arrangement in which peripheral surfaces thereof are parallel to the power transmission surfaces 124 a and 124 a of the power transmission unit 124 of the driver support base 123. The pair of flywheels 133A and 133B are rotationally driven at high speeds in opposite directions. For this reason, when the left and right power transmission surfaces 124a and 124a of the driver support base 123 are pressed against the peripheral surfaces of the pair of flywheels 133A and 133B, the driver support base 123 has the power transmission surfaces 124a and 124a and the flywheel outer peripheral surface. Is moved in the driving direction by friction between the two.

  The support shafts 135A and 135B of the pair of flywheels 133A and 133B are rotatably supported by a bearing 137. Driven pulleys 143A and 143B are mounted on the respective support shafts 135A and 135B, and the driven pulleys 143A and 143B and the flywheels 133A and 133B rotate integrally. The driven pulleys 143A and 143B are V pulleys having three circumferential V grooves on the outer peripheral surface.

  The pair of flywheels 133A and 133B are driven separately by two drive motors 113A and 113B. The two drive motors 113A and 113B are arranged such that their rotational axes are parallel to the corresponding flywheels 133A and 133B. That is, the two drive motors 113A and 113B are in a V-shaped arrangement, which are V-shaped when viewed from the nail driving direction (see FIG. 4).

The two drive motors 113A and 113B are set so that the rotation directions are opposite to each other, and one drive pulley 115A and 115B is attached to the output shaft. Each of the driving pulleys 115A and 115B is a V pulley having three circumferential V grooves on the peripheral surface, like the driven pulleys 143A and 143B. Each of the drive belts 145A and 145B is looped around the drive pulleys 115A and 11B and the driven pulleys 143A and 143B corresponding to each other in parallel. Accordingly, the pair of flywheels 133A and 133B are rotationally driven separately by the drive motors 113A and 113B, respectively. Each of the drive belts 145A and 145B is a V-belt having three V-shaped ridges. The meshed engagement between the V-shaped ridges and the V-grooves enables efficient rotational power transmission with less slip and the rotation from each pulley. Stopping is realized.
In the present embodiment, the flywheels 133A and 133B that are in contact with the left and right power transmission surfaces 124a and 124a of the driver support base 123 are driven separately by the drive motors 113A and 113B, respectively. For this reason, it is necessary to synchronize the peripheral speeds of the flywheels 133A and 133b, that is, the rotational speeds of the drive motors 113A and 113B. A method for synchronizing the rotation speeds of the drive motors 113A and 113B will be described later.

  Further, as shown in FIGS. 2 and 3, the drive motors 113A and 113B are located behind the flywheels 133A and 133B, that is, on the rear end side (upper side in FIG. 1) of the main body housing 110. In the driving direction of 123, they are arranged at positions separated (shifted). That is, the distance between the axes of one drive motor 113A and the corresponding one flywheel 133A and the distance between the other drive motor 113B and the corresponding other flywheel 133B are arranged differently. .

  Further, as shown in FIGS. 1, 3 and 5, the drive mechanism 131 presses the driver support base 123 against the flywheels 133A and 133B from the lateral direction (direction intersecting the nail driving direction) via the pressing roller 163. A pressing mechanism 161 is included. The pressing mechanism 161 has an electromagnetic actuator 165. The electromagnetic actuator 165 is disposed on the front portion (lower side in FIGS. 1 and 3) in the main body housing 110. The output shaft 166 of the electromagnetic actuator 165 is biased to the protruding side by a compression spring 167. When the electromagnetic actuator 165 is energized, the output shaft 166 moves to the drawing side against the compression spring 167. When the energization is interrupted, the output shaft 166 is returned to the protruding side by the compression spring 167.

  One end of the operating arm 171 is connected to the tip of the output shaft 166 of the electromagnetic actuator 165 via a bracket 169 so as to be relatively rotatable. A long connecting hole 169 a is formed in the bracket 169 in a direction orthogonal to the moving direction of the output shaft 166. An operating arm 171 is connected to the bracket 169 via a connecting shaft 173 inserted through the connecting hole 169a. For this reason, one end side of the operation arm 171 is in a state in which the rotation center can be displaced within a range in which the connection shaft 173 that can be rotated through the connection shaft 173 and can be moved in the connection hole 169a. It is connected to the bracket 169.

The operating arm 171 is bent in an L shape and extends rearward (upward in FIG. 1). One end side of the restricting arm 177 is rotatably connected to the other end side of the operating arm 171 via a first movable support shaft 175. The restriction arm 177 is rotatably connected to the main body housing 110 via a first fixed support shaft 179. The other end of the operating arm 171 is rotatably connected to the pressing arm 183 via the second movable support shaft 181. The pressing arm 183 is rotatably supported by the main body housing 110 via the second fixed support shaft 185. A pressing roller 163 is rotatably supported on the rotating tip side (the upper side in FIG. 1) of the pressing arm 183.
The urging roller 150 is rotatably supported by a leaf spring 150 a supported by the main body housing 110. The urging roller 150 contacts the power transmission surfaces 124a and 124a of the driver support base 123, and holds the driver support base 123 in a state of being separated from the flywheels 133A and 133B by the urging force of the leaf spring 150a.

  In the pressing mechanism 161 configured as described above, the energization of the electromagnetic actuator 165 is cut off when the driver 121 is placed at the standby position, and therefore the output shaft 166 is returned to the protruding side by the compression spring 167. Yes. In this standby state, the base end side (connection shaft 173 side) of the operating arm 171 is displaced obliquely downward to the right in FIG. Therefore, the regulating arm 177 tilts around the first fixed support shaft 179, and the pressing roller 163 does not press (separate) the back surface of the driver support base 123. Therefore, the power transmission surfaces 124a and 124a of the driver support base 123 are placed in a state of being separated from the peripheral surfaces of the pair of flywheels 133A and 133B by the biasing force from the biasing roller 150.

  On the other hand, when the electromagnetic actuator 165 is energized, the output shaft 166 is moved to the drawing side against the compression spring 167, and accordingly, the base side of the operating arm 171 is moved obliquely upward to the left, and the restriction arm 177 is moved to the first position. The pressing arm 183 is tilted clockwise about the second fixed support shaft 185 by tilting clockwise about the first fixed support shaft 179. Therefore, the pressing roller 163 presses the back surface of the driver support base 123 and moves the power transmission surfaces 124a and 124a of the driver support base 123 to a pair while retreating the biasing roller 150 against the biasing force of the leaf spring 150a. Press against the peripheral surface of the flywheel 133A, 133B. At this time, at a connection point between the first fixed support shaft 179 of the restriction arm 177 and the first movable support shaft 175 that is a connection point between the operation arm 171 of the restriction arm 177 and the pressing arm 183 of the operation arm 171. A certain second movable support shaft 181 is positioned on the straight line L. Therefore, the pressing arm 183 is fixed (locked) in a state in which the pressing roller 163 presses the driver support base 123 against the flywheels 133A and 133B.

  That is, the pressing mechanism 161 locks the pressing roller 163 at the pressing position by a toggle mechanism including the first fixed support shaft 179, the first movable support shaft 175, and the second movable support shaft 181, and the flywheel 133A. , 133B functions to maintain the pressed state of the driver support base 123 against the peripheral surface. When the driver support base 123 is pressed against the peripheral surfaces of the pair of flywheels 133A and 133B that rotate at high speed, the driver 121 moves at a high speed together with the driver support base 123 toward the driver guide 111 by the rotational energy of the flywheels 133A and 133B. Then, the nail n is hit and driven into the workpiece.

Next, the return mechanism 191 that returns the driver 121 that has been driven into the nail n to the standby position will be described. As shown mainly in FIG. 2, the return mechanism 191 includes left and right return rubbers 193 having a string-like elasticity for pulling back the driver 121, left and right winding wheels 195 for winding the return rubber 193, and the winding wheel 195. A mainspring spring 195b for rotating in the winding direction is mainly used.
The left and right winding wheels 195 are arranged in a rear region (upper region in FIG. 2) of the main body housing 110 and rotate together with one winding shaft 195a that is rotatably supported by a bearing. A mainspring spring 195b is disposed on the winding shaft 195a. The mainspring spring 195b has one end fixed to the main body housing 110 and the other end fixed to the winding shaft 195a, and generates a force for rotating the winding wheel 195 in the winding direction together with the winding shaft 195a. One end of the left and right return rubbers 193 is fixed to the left and right winding wheels 195, and the other end is fixed to the side surface of the driver support base 123.
The driver 121 is pulled by the return rubber 193 together with the driver support base 123 and is held at a standby position where the driver support base 123 abuts against the stopper 197. As shown in FIG. 1, the contact surface 197a of the stopper 197 with the driver support base 123 is formed in a circular arc shape having a concave shape in the front. Corresponding to this, the rear end surface of the driver support base 123 is formed in a convex arcuate shape. Thereby, when the driver 121 returns to the standby position, it is possible to improve the restoration property of the driver 121 to the home position.

  The driver guide 111 is provided with a contact arm 127 for turning on / off a contact arm switch (not shown for the sake of convenience) for starting / stopping control of the drive motors 113A, 113B. The contact arm 127 is attached so as to be movable in the long axis direction of the driver guide 111 (the long axis direction of the nail n), and is urged so as to protrude from the tip of the driver guide 111 by a spring not shown for convenience. When the contact arm 127 is in the protruding position, the contact arm switch is turned off, and when the contact arm 127 is moved to the main body housing 110 side, the contact arm switch is turned on. Further, the handle portion 103 is provided with a trigger 104 that is pulled by an operator and returned to the original position when the pulling operation is released. When the trigger 104 is pulled, a trigger switch (not shown) is turned on for convenience, the electromagnetic actuator 165 of the pressing mechanism 161 is energized, and the trigger switch is turned off by releasing the pulling operation of the trigger 104. The energization of the actuator 165 is cut off.

Next, a method for synchronizing the rotation speeds of the drive motors 113A and 113B will be described.
In the present embodiment, the left and right power transmission surfaces 124a and 124a of the driver support base 123 are in contact with the outer peripheral surfaces of flywheels 133A and 133B that are rotationally driven by the drive motors 113A and 113B, respectively. The driver support base 123 is driven by a frictional force between the left and right power transmission surfaces 124a and 124a and the flywheels 133A and 133B. For this reason, it is necessary to synchronize the peripheral speeds of the flywheels 133A and 133B, that is, the rotational speeds of the drive motors 113A and 113B. Thus, in the present embodiment, the driver support base 123 is jointly driven by the flywheels 133A and 133B that are rotationally driven by the drive motors 113A and 113B, that is, jointly driven by the drive motors 113A and 113B. Yes.
Conventionally, as a method of synchronizing the rotation speeds of two motors, for example, a method of controlling the rotation speed of one motor based on the difference between the rotation speeds of both motors is used. For example, a rotation speed control device is provided in one motor, and a rotation speed detector is provided in one and the other motor. The rotation speed control device provided in one motor detects the difference between the rotation speeds of the one motor and the other motor detected by the rotation speed detector provided in the one and the other motor, and the detected rotations of both motors. Based on the difference in number, the voltage or current supplied to one motor is controlled. Alternatively, a method is used in which both motors are provided with a rotation speed control device that controls the rotation speed of the motor to the set rotation speed, and both motors are controlled to the same set rotation speed. However, these synchronization methods require a complicated and expensive rotational speed control device.
Therefore, in the present embodiment, the following method is used as a method of synchronizing the rotational speeds of the two drive motors 113A and 113B that drive the driver support base 123 jointly.

In a motor such as a DC magnet motor, a DC brushless motor, or a universal motor, the rotational speed N is expressed by the following equation.
N = (V−I × R) / K _E
Here, [V] is the motor terminal voltage, [I] is the motor current, [R] is the armature resistance of the motor, and [K _E ] is a constant. In this equation, the voltage drop due to the contact resistance of the brush of the DC motor is ignored.
The torque T is expressed by the following formula.
T = K _T × I
Here, [K _T ] is a constant.
From the above equation, when the motor load (torque [T]) is changed in the state where the motor is connected to the constant voltage power source, the motor current [I], and therefore the motor rotation speed [N], is changed. Change. For example, when the motor load increases, the motor current [I] increases and the motor speed [N] decreases.
In the present embodiment, motors selected from such DC magnet motors, DC brushless motors, and universal motors are used as the drive motors 113A and 113B.
As shown in FIG. 7, the drive motors 113 </ b> A and 113 </ b> B are connected in parallel to the output terminal of the voltage adjustment circuit 220. The voltage adjustment circuit 220 is configured by, for example, a PWM control circuit that inputs a DC voltage of the battery 200 and outputs a voltage pulse having a predetermined duty ratio (= on period / off period) from an output terminal (+ OUT). The output terminal (+ OUT) in FIG. 7 corresponds to the “common output terminal of the voltage regulator circuit” of the present invention. In this case, the voltage of the DC power source (the terminal voltages of the motors 113A and 113B) output from the output terminal (+ OUT) of the voltage adjustment circuit 220 is a value corresponding to the duty ratio of the voltage pulse output from the voltage adjustment circuit 220. Become. That is, the rotation speed [N] of the drive motors 113A and 113B corresponds to the load (current [I]) and corresponds to the duty ratio of the voltage pulse output from the output terminal (+ OUT) of the voltage adjustment circuit 220. The rotation speed is determined based on the terminal voltage [V] having the above and the above-described equation.
The drive circuits 231a and 231b are circuits for selecting an armature winding for supplying a voltage pulse according to the position of the rotor. The drive circuits 231a and 231b are used when a DC brushless motor is used as the drive motors 113A and 113B.
A rotation speed setting device for setting the rotation speed may be provided, and the voltage adjustment circuit 220 may be configured to output a voltage pulse having a duty ratio corresponding to the rotation speed setting value set by the rotation speed setting device. . In addition, the voltage adjustment circuit 220 can output a voltage pulse having a duty ratio of 100% (off period = 0).

A control circuit 210 is also provided. The control circuit 210 inputs an on / off signal of the contact 127a of the contact arm 127 described above. When the ON signal of the contact 127a is input (when the contact arm 127 is in the protruding position), the control circuit 210 outputs a start signal to the voltage adjustment circuit 220. When the start signal is output from the control circuit 210, the voltage adjustment circuit 220 supplies a voltage pulse having a predetermined duty ratio to the first motor 113A and the second motor 113B from the output terminal (+ OUT). On the other hand, the control circuit 210 outputs a stop signal to the voltage adjustment circuit 220 when the OFF signal of the contact 127a is input (when the contact arm 127 is moved to the main body housing 110 side). When the stop signal is output from the control circuit 210, the voltage adjustment circuit 220 stops supplying the voltage pulses to the drive motors 113A and 113B.
Thus, in a state where voltage pulses having a predetermined duty ratio are applied to the drive motors 113A and 113B (a state where the drive motors 113A and 113B are connected to a constant voltage power source), the drive motors 113A and 113B The rotation speed is automatically synchronized.
Consider a case where the flywheels 133A and 133B have the same diameter. In this case, when the rotational speeds of the drive motors 113A and 113B for rotating the flywheels 133A and 133B are equal, the peripheral speeds of the flywheels 133A and 133B are equal, that is, they are synchronized. Here, if the rotational speeds of the flywheels 133A and 133B driven by the drive motors 113A and 113B are different, the load of the drive motor 113A or 113B driving the flywheel 133A or 133B having the higher rotational speed. Becomes larger. As a result, the current of the drive motor with increased load increases and the rotational speed decreases. For example, when the rotational speed of the flywheel 133A is higher than the rotational speed of the flywheel 133B, the load on the drive motor 113A that rotationally drives the flywheel 133A is increased, thereby reducing the rotational speed of the drive motor 113A. To do. This reduction in the rotational speed of the drive motor 113A is performed until the rotational speed of the drive motor 113A matches the rotational speed of the drive motor 113B, that is, until the peripheral speeds of the flywheels 133A and 133B match.

  As described above, in the present embodiment, as the drive motors 113A and 113B for rotating and driving the flywheels 133A and 133B, motors whose rotational speed changes in accordance with changes in loads (for example, DC magnet motors, DC brushless motors, Universal motor etc. are used. The drive motors 113A and 113B are connected to a constant voltage power source. Thereby, it is possible to synchronize the drive motors 113A and 113B that drive the driver support base 123 jointly easily and inexpensively.

7, the DC voltage of the battery 200 is adjusted by the voltage adjustment circuit 220 and applied to the drive motors 113A and 113B. However, the DC voltage of the battery 200 is applied to the drive motors 113A and 113B without passing through the voltage adjustment circuit 220. It can also be applied. Here, the DC voltage of the battery 200 is maintained at a substantially equal value in a normal state. Therefore, even when the DC voltage of the battery 200 is applied to the drive motors 113A and 113B without passing through the voltage adjustment circuit 220, it is said that “the drive motors 113A and 113B are connected to a constant voltage power source”. it can. In this case, for example, the contact 127a of the contact arm switch is connected between the battery 200 and the drive motors 113A and 113B.
In FIG. 7, the control circuit 210 and the voltage adjustment circuit 220 are used. However, one control circuit having the function of the control circuit 210 and the function of the voltage adjustment circuit 220 may be used.

  Next, the operation and usage of the nailing machine 100 configured as described above will be described. When the operator grasps the handle portion 103 and presses the contact arm 127 against the workpiece, the contact arm 127 is pushed by the workpiece and moves backward toward the main body housing 110 side. As a result, the contact arm switch is turned on, and the drive motors 113A and 113B are energized. The rotational outputs of the drive motors 113A and 113B are transmitted to the flywheels 133A and 133B via the drive pulleys 115A and 115B, the drive belts 145A and 145B, and the driven pulleys 143A and 143B. Is driven to rotate.

  When the trigger 104 is pulled in this state, the trigger switch is turned on, the electromagnetic actuator 165 is energized, and the output shaft 166 is pulled. As a result, the operating arm 171 is displaced and the pressing arm 183 tilts in the pressing direction about the second fixed support shaft 185, and the back surface of the driver support base 123 is pressed by the pressing roller 163. The driver support base 123 pressed by the pressing roller 163 is pressed against the peripheral surfaces of the pair of flywheels 133A and 133B. For this reason, the driver 121 is linearly moved in the driving direction by the rotational force of the flywheels 133A and 133B together with the driver support base 123, and hits the nail n at the tip thereof and drives it into the workpiece. At this time, the return rubber 193 is pulled out from the winding wheel 195, and the mainspring spring 195b is wound.

After the driver 121 finishes driving the nail n, when the pulling operation of the trigger 104 is released, the energization to the electromagnetic actuator 165 is cut off. As a result, the output shaft 166 of the electromagnetic actuator 165 is returned to the protruding direction by the compression spring 167, and the operating arm 171 is displaced. When the operating arm 171 is displaced, the first movable support shaft 175 is disengaged from the straight line connecting the first fixed support shaft 179 and the second movable support shaft 181 and the toggle mechanism is released. Further, the pressing arm 183 tilts counterclockwise about the second fixed support shaft 185, and the pressing of the driver support base 123 by the pressing roller 163 is released.
When the pressing by the pressing roller 163 is released, the driver support base 123 is pulled by the return rubber 193 and returned to the standby position shown in FIG. The return rubber 193 has its own elasticity toward the contraction side, and is taken up by a take-up wheel 195 spring-biased on the take-up side. For this reason, even if the driver support base 123 is moved with a large stroke in the driving direction, the driver support base 123 can be surely returned to the standby position, and the back rubber 193 can be reduced to reduce durability. Can be increased.

Here, if the drive motors 113A and 113B are energized at the same time when the drive motors 113A and 113B are started, the voltage of the battery 200 is reduced by the start-up current of the drive motors 113A and 113B. Such a decrease in battery voltage causes the following problems.
The electric power tool may be provided with a remaining capacity detection device that detects the remaining capacity of the battery 200 based on the battery voltage. When the battery voltage decreases due to the starting currents of the drive motors 113A and 113b, even if the remaining capacity of the battery 200 is present, this remaining capacity detecting device may be erroneously detected. In addition, the activation time of the drive motors 113A and 113B becomes longer.
For this reason, it is preferable to use a method of starting the drive motors 113A and 113B while suppressing a decrease in the battery voltage (referred to as “soft start”).
Hereinafter, a battery voltage decrease suppressing device that suppresses a decrease in battery voltage when starting the drive motors 113A and 113B will be described.

The 1st aspect of a battery voltage fall suppression apparatus is shown in FIG. In the battery voltage drop suppression device of the first aspect shown in FIG. 8, when the drive motors 113A and 113B are started, the voltage applied to the drive motors 113A and 113B is gradually increased. For example, the duty ratio of the voltage pulse output from the output terminal (+ OUT) of the voltage adjustment circuit 220 is gradually increased. The battery voltage drop suppression device shown in FIG.
When the start signal is output from the control circuit 210, the voltage adjustment circuit 220 first outputs a voltage pulse with a low duty ratio. Thereafter, the duty ratio of the voltage pulse is sequentially increased to a designated duty ratio (for example, a duty ratio corresponding to the speed setting value).
FIG. 9 shows the operation of the battery voltage drop suppression device of the first aspect shown in FIG.
In FIG. 9, a start signal is output from the control circuit 210 at time t1. When the start signal is output from the control circuit 210 at time t1, the voltage adjustment circuit 220 changes the duty ratio of the voltage pulse ([ON period n / OFF period f] in the period T) from (n1 / f1) to (n5). / F5) in order. As a result, the drive motor 113A. The starting current of 113B is reduced, and the voltage drop of the battery 200 is suppressed. For example, the battery voltage at startup of the drive motors 113A and 113B is E1 when the voltage drop suppression device is not used, but E2 (> E1 when the voltage drop suppression device of the first aspect is used. )
In the voltage drop suppression device of the first aspect, the battery voltage drop can be suppressed by adjusting the duty ratio of the voltage pulse output from the voltage adjustment circuit.

The 2nd aspect of a battery voltage fall suppression apparatus is shown in FIG. In the battery voltage drop suppression device of the second aspect shown in FIG. 10, when the drive motors 113A and 113B are started, the time point at which the voltage is applied to the drive motors 113A and 113B is shifted. For example, the starting time (starting timing) of the drive motors 113A and 113B is shifted. 10 includes a control circuit 210 and switches 241a and 241b. When the voltage adjustment circuit 220 has the function of the control circuit 210, the voltage adjustment circuit 220 includes the voltage adjustment circuit 220 and switches 241a and 241b.
When the start signal is output from the control circuit 210, the voltage adjustment circuit 220 outputs a voltage pulse having a designated duty ratio from the output terminal (+ OUT). At this time, when the start signal is output, the control circuit 210 first turns on the switch 241a corresponding to the drive motor 113A. Thereby, first, application of a voltage pulse to the drive motor 113A is started. Note that the switch 241a can be omitted. In addition, the control circuit 210 turns on the switch 241b corresponding to the drive motor 113B when a set period has elapsed since the start of application of the voltage pulse to the drive motor 113A. Thereby, application of the voltage pulse to the drive motor 113B is started.
The operation of the battery voltage drop suppression device of the second aspect shown in FIG. 10 is shown in FIG.
A start signal is output from the control circuit 210 at time t11. At time t11, the switch 241a is turned on, and application of a voltage pulse to the drive motor 113A is started. At this time, since the voltage pulse is applied only to the drive motor 113A, the startup current is smaller than that when the drive motors 113A and 113B are started simultaneously. For this reason, the battery voltage drop is small. Then, at time t12 when the set period Tx has elapsed from time t11, the switch 241b is turned on, and application of a voltage pulse to the drive motor 113B is started. At this time, since the starting current of the drive motor 113A has decreased, the starting current is smaller than when the drive motors 113A and 113B are started simultaneously. Therefore, the voltage drop of the battery 200 is suppressed. For example, the battery voltage at the start of the drive motors 113A and 113B is E1 when the voltage drop suppression device is not used, but E12 (> E1 when the voltage drop suppression device of the second aspect is used. )
In the voltage drop suppression device according to the second aspect, the battery voltage drop can be suppressed by adjusting the on-point of the start switch provided in the drive motor.

The example of a change of the battery voltage fall suppression apparatus of a 2nd aspect is shown in FIG. The battery voltage drop suppression device shown in FIG. The voltage adjustment circuit 250 receives, for example, the voltage of the battery 200 and applies a first voltage pulse and a second voltage pulse having a predetermined duty ratio to the first output terminal (+ OUT1) and the second output terminal (+ OUT2). ) To output the PWM control circuit. The drive motor 113A is connected to the first output terminal (+ OUT1), and the drive motor 113B is connected to the second output terminal (+ OUT2). The timing of the first voltage pulse and the second voltage pulse output from the first output terminal (+ OUT1) and the second output terminal (+ OUT2) (for example, when the voltage pulse rises) can be set as appropriate. The battery voltage drop suppression device shown in FIG.
The first output terminal (+ OUT1) and the second output terminal (+ OUT2) correspond to “a plurality of output terminals of the voltage regulator circuit” of the present invention.
When a start signal is output from the control circuit 210 at time t11, the voltage adjustment circuit 250 first outputs a first voltage pulse having a designated duty ratio from the first output terminal (+ OUT1). Thereby, first, application of a voltage pulse to the drive motor 113A is started. Then, the voltage adjustment circuit 250 starts the output of the first voltage pulse from the first output terminal (+ OUT1) (after starting the application of the voltage pulse to the drive motor 113A), and the set period Tx has elapsed. At time t12, the second voltage pulse having the designated duty ratio is output from the second output terminal (+ OUT2). Thereby, application of the voltage pulse to the drive motor 113B is started.
In the present embodiment, when the driver support base 123 is driven, the rotational speed of the drive motor 113A and the rotational speed of the 113B need only be synchronized. Therefore, in the steady state after the drive motors 113A and 113B are activated, the first voltage pulse and the second voltage output from the first output terminal (+ OUT1) and the second output terminal (+ OUT2) of the voltage adjustment circuit 250 are output. The phase of the voltage pulse may be different.
In the modified example of the voltage drop suppression device according to the second aspect, a voltage adjustment circuit having a plurality of output terminals is provided, and the voltage drop of the battery is suppressed by adjusting the generation time point of the voltage pulse from each output terminal. it can.

  The voltage adjustment circuit 250 shown in FIG. 12 can be used in place of the voltage adjustment circuit 220 shown in FIG. In this case, for example, the drive motor 113A is connected to the first output terminal (+ OUT1) of the voltage adjustment circuit 250, and the drive motor 113B is connected to the second output terminal (+ OUT2). When the start signal is output from the control circuit 210, the voltage adjustment circuit 250 is a first voltage whose duty ratio gradually increases from the first output terminal (+ OUT1) and the second output terminal (+ OUT2). A pulse and a second voltage pulse are output.

The 3rd aspect of a battery voltage fall suppression apparatus is shown in FIG. In the battery voltage drop suppression device of the third aspect shown in FIG. 13, when the drive motors 113A and 113B are started, the voltage applied to the drive motors 113A and 113B is gradually increased and the drive motors 113A and 113B0 are applied. The time point at which the voltage is applied is shifted. The battery voltage drop suppression device shown in FIG. The voltage adjustment circuit 250 receives, for example, the voltage of the battery 200 and applies a first voltage pulse and a second voltage pulse having a predetermined duty ratio to the first output terminal (+ OUT1) and the second output terminal (+ OUT2). ) To output the PWM control circuit.
When the start signal is output from the control circuit 210, the voltage adjustment circuit 250 firstly outputs a first voltage pulse having a low duty ratio and a first output pulse from the first output terminal (+ OUT1) and the second output terminal (+ OUT2). 2 voltage pulses are output. Thereafter, the duty ratios of the first voltage pulse and the second voltage pulse output from the first output terminal (+ OUT1) and the second output terminal (+ OUT2) are sequentially increased to the designated duty ratio. At this time, the output time points of the first voltage pulse and the second voltage pulse are shifted so that the first voltage pulse and the second voltage pulse are not output simultaneously. For example, the rising time points of the first voltage pulse and the second voltage pulse are shifted. In FIG. 14, the rising time of the first voltage pulse is arranged in the first half of the pulse period T, and the rising time of the second voltage pulse is arranged in the second half of the pulse period T.
Here, the starting currents of the drive motors 113A and 113B are reduced in several pulse cycles. For this reason, the duty ratio of the first voltage pulse and the second voltage pulse is reduced only during several cycles of the pulse period (only while several voltage pulses are applied), and the first voltage pulse and the second voltage pulse are reduced. It is sufficient that the two voltage pulses are not output simultaneously. In FIG. 14, the duty ratios of the first to fifth first voltage pulses and the second voltage pulse are sequentially increased in the order of (f1 / n1) to (n5 / f5). Further, the output time points of the first voltage pulse and the second voltage pulse are adjusted so that the first to fourth voltage pulses and the second voltage pulse are not output simultaneously.
As described above, in the steady state after the drive motors 113A and 113B are started, the first voltage output from the first output terminal (+ OUT1) and the second output terminal (+ OUT2) of the voltage adjustment circuit 250. The phase of the pulse and the second voltage pulse may be different. Of course, one phase of the first voltage pulse and the first voltage pulse may be adjusted so that the phases of the first voltage pulse and the second voltage pulse coincide with each other in the steady state.
In the voltage drop suppression device of the third aspect, a voltage adjustment circuit having a plurality of output terminals is provided, and the voltage drop duty ratio of each output terminal and the output time point of the voltage pulse are adjusted to suppress the battery voltage drop. can do.
In the battery voltage drop suppression device according to the third aspect, the drive pulses can be applied to the drive motors 113A and 113B almost simultaneously, so the drive motors 113A. 113B can be activated in a short time.

  In this embodiment, the driver support base 123 is provided with power transmission surfaces 124a and 124a having a V-shaped cross section, and the power transmission surfaces 124a and 124a are pressed against the outer peripheral surfaces of flywheels 133A and 133B arranged in a V shape. The driver support base 123 is moved. For this reason, the power transmission surfaces 124a and 124a of the driver support base 123 bite into the outer peripheral surfaces of the pair of flywheels 133A and 133B (wedge action). As a result, power is efficiently transmitted from the flywheels 133A and 133B (drive motors 113A and 113B) to the driver support base 123, and the striking force of the driver 121 can be increased. In addition, the pair of flywheels 133A and 133B (drive motors 113A and 113B) can be easily and inexpensively synchronized.

  In the present embodiment, the pair of flywheels 133A and 133B is configured to be driven separately by two drive motors 113A and 113B. This makes it possible to employ a parallel belt transmission system. In the parallel belt transmission system, for example, as the drive belts 145A and 145B, V-belts having a plurality of V-shaped (or singular) ridges having high transmission efficiency compared to a round belt having a circular cross section are used. It becomes possible. As a result, the pair of flywheels 133A and 133B are driven efficiently, and the impact force of the driver 121 can be further increased.

  By the way, when the two drive motors 113A and 113B are arranged so that each rotation axis forms a V shape when viewed from the moving direction of the driver support base 123 (V type arrangement), the drive motors 113A and 113B are shafts. If the direction is long, the motors may interfere with each other at one end in the axial direction. In order to prevent this interference, if the interval between the motors is increased, the width of the main body 101 is increased and the size is increased. According to the present embodiment, the two drive motors 113A and 113B are arranged at positions shifted from each other in the driving direction of the driver support base 123. Thereby, the mutual interference in the axial direction one end part of drive motor 113A, 113B can be avoided. That is, according to the present embodiment, while the drive motors 113A and 113B are arranged in a V shape, the width of the main body 101 (in the left-right direction in FIG. 1), that is, the width of the nailing machine 100 can be reasonably suppressed. And can be made compact.

(Second embodiment of the present invention)
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 15 is a side view of the electric nail driver according to the present embodiment. FIG. 16 is a cross-sectional view illustrating a first arrangement example regarding the V-type arrangement of the flywheel and the motor. FIG. 17 is a plan sectional view showing a second arrangement example regarding the V-type arrangement of the flywheel and the motor.

  In the second embodiment, a pair of flywheels 133A and 133B is used with a direct connection system in which the drive motors 113A and 113B are directly driven without using a power transmission member. Other points are substantially the same as those of the first embodiment described above. For this reason, description is abbreviate | omitted except the direct connection system of a flywheel and a motor, and the structure relevant to it. The same reference numerals as those used in the description of the first embodiment are used for the same constituent members.

In the first arrangement example, as shown in FIG. 16, the two drive motors 113 </ b> A and 113 </ b> B and the pair of flywheels 133 </ b> A and 133 </ b> B are driven by the operator holding the handle portion 103 and driving the main body 101 into the driver 121. When viewed from the rear side, the rotation axis is arranged in an inverted V shape. In other words, the two drive motors 113A, 113B and the pair of flywheels 133A, 133B have their rotation axes on the upper side of the main body 101, that is, from the front side in the pressing direction of the pressing roller 160 (upper side in FIG. 16). It is a V-shaped arrangement that is open (expands) toward the portion 103 side.
In FIG. 16, the flywheels 133A and 133B are disposed on the upper side of the main body 101, and the drive motors 113A and 113B are disposed on the lower side (the handle portion 103 side).

In the second arrangement example, as shown in FIG. 17, the two drive motors 113 </ b> A and 113 </ b> B and the pair of flywheels 133 </ b> A and 133 </ b> B are driven by the operator holding the handle portion 103 and driving the main body portion 101 with the driver 121. When viewed from the rear side of the direction, it is arranged to be V-shaped. In other words, the two drive motors 113A and 113B and the pair of flywheels 133A and 133B have their rotation axes closed (narrower) from the upper side of the main body 101 (upper side in FIG. 17) toward the handle 103. ) V-shaped arrangement.
In FIG. 17, the drive motors 113A and 113B are disposed on the upper side of the main body 101, and the flywheels 133A and 133B are disposed on the lower side (the handle portion 103 side).

  In the second embodiment, a direct connection system is employed in which flywheels 133A and 133B are provided on the output shafts of the drive motors 113A and 113B. As a result, there is no power transmission loss, there is no failure related to the power transmission unit, and the entire length of the nailing machine 100 compared to the system in which transmission is performed via the power transmission member (drive belts 145A and 145B). (Vertical length in FIG. 16) can be shortened (in the configuration in which the power transmission member is interposed, the total length may be increased by arranging the power transmission member while avoiding interference with other parts) Is advantageous.

  Further, according to the first arrangement example shown in FIG. 16, compared to the second arrangement example shown in FIG. 17, the outline of the main body 101 based on the first arrangement example is shown by a two-dot chain line in FIG. ), The lateral width (the horizontal dimension in FIGS. 16 and 17) of the upper portion (the upper side in FIGS. 16 and 17) of the main body 101 can be reduced. Thereby, when an operator performs nail driving | operation, it becomes easy to see the nailing location in a workpiece, and the visibility of a nail driving location can be improved.

The present invention is not limited to the embodiments described above, and various modifications, additions, and deletions can be made without departing from the concept of the present invention.
Although the case where the driver support base 123 of the electric nailing machine is driven by a plurality of drive motors has been described, the technique of the present invention is applied to driving various movable bodies for processing a workpiece. be able to.
The driver support (movable body) 123 is connected to two drive motors 113A. Although the case of driving jointly by 113B has been described, the number of motors driving the movable body jointly may be three or more.
Although the case where the movable body is driven by pressing the flywheels 133A, 133B against the movable body by the drive motors 113A, 113B has been described, various modes other than this are available as a mode in which the movable body is driven jointly by a plurality of motors. Embodiments can be used.
Although a universal motor, a direct current magnet motor, and a direct current brushless motor are used as motors that drive the movable body jointly, various motors whose rotational speed changes according to a change in load can be used.
As a motor that drives the movable body jointly, a motor that has a characteristic that the number of revolutions changes according to a change in load is used. A control device for controlling the rotation speed of the motor can also be provided. For example, the loads of a plurality of motors are detected, and the rotational speed of the motor with the larger load is reduced.
The battery voltage drop suppression device can be omitted.
In the first embodiment, a method of transmitting the rotation output of the drive motors 113A and 113B to the flywheels 133A and 133B via a power transmission member is used. In the second embodiment, the drive motors 113A and 113B are Although the method of directly connecting to the flywheels 133A and 133B is used, both methods can be used in combination. For example, a method using a power transmission member is used for one flywheel 133A, and a direct connection method is used for the other flywheel 133B.
The power transmission member is not limited to the V-belt, and other belts such as a round belt and a timing belt (toothed belt), and other types of power transmission members such as gears can be used.
In order to correspond to the power transmission portion 124 having a V-shaped cross section of the driver support base 123, the flywheels 133A and 133B are arranged so that their rotation axes are V-shaped. ) Corresponding to the power transmission surfaces (first and second contact surfaces) 124a and 124a that are provided at 123 and extend so that the distance between them is reduced toward the front in the pressing direction of the pressing roller (pressing member) 163. The contact surfaces of the flywheels (first and second rotating bodies) 133A and 133B that are in contact with the power transmission surface are narrowed toward each other toward the front in the pressing direction of the pressing roller (pressing member) 163. It is sufficient if the configuration extends. For example, the outer peripheral surfaces of the flywheels 133A and 133B are formed by conical inclined surfaces having an inclination angle corresponding to the inclination angle of the power transmission surface 124a of the power transmission unit 124 so that the rotation axes of the flywheels 133A and 133B are parallel to each other. You may arrange in.
Each configuration described in the embodiment can be used alone, or a plurality selected as appropriate can be used in combination.

The present invention can also be configured as follows.
(Aspect 1) “The power tool according to claim 7, wherein the first motor and the second motor are disposed at positions separated along a moving direction of the movable body. Power tool. "
In this aspect, “arranged at positions away from the moving direction of the movable body” means, for example, when the first and second rotating bodies are driven via a rotational power transmission member such as a belt, a chain, or a gear. A mode in which the inter-axis distance between the first rotating body and the first motor and the inter-axis distance between the second rotating body and the second motor are arranged differently corresponds to this.
According to the first aspect of the present invention, it is possible to avoid the first and second motors that rotationally drive the first and second rotating bodies from interfering with each other at one end in the axial direction. Thereby, a V-type arrangement configuration can be obtained while suppressing an increase in size.

(Aspect 2) “The power tool according to claim 7 or 1, wherein the first rotating body is provided on an output shaft of the first motor, and the first rotary body is provided on the output shaft of the second motor. An electric tool characterized in that a rotating body of 2 is provided. "
According to the invention described in the aspect 2, since the motor and the rotating body are directly connected, there is no power transmission loss and there are few failures.

(Aspect 3) "The electric tool according to any one of claims 7, 1 and 2, wherein the first and second motors and the first and second rotating bodies are housed, and A handle portion that is connected to the housing and extends in a direction intersecting the longitudinal direction of the housing and gripped by an operator, and the first and second motors are viewed from the moving direction of the movable body. The electric power tool is characterized in that its rotational axis is arranged in a V shape that opens from the front side in the pressing direction of the pressing member toward the handle portion side.
According to the invention described in the aspect 3, the lateral width of the housing that accommodates the motor and the rotating body can be reduced, and the visibility of the placement location of the placement material on the workpiece is improved.

(Aspect 4) “The electric tool according to any one of claims 7 and 1 to 3, wherein the rotation output of the motor is transmitted to the rotating body by a V-belt. Work tools."
According to the invention described in the aspect 4, power transmission between the motor and the rotating body can be efficiently performed.

It is a side view which shows the whole structure of 1st Embodiment. It is a X-ray arrow line view of FIG. 1, and shows the principal part of an electric nail driver. It is a perspective view which shows the principal part of 1st Embodiment. It is the YY sectional view taken on the line of FIG. It is a side view of the press mechanism which presses a driver support stand to a flywheel. It is a perspective view of a driver and a driver support stand. It is a figure which shows the connection state of a drive motor and a battery. It is a figure which shows the 1st aspect of a battery voltage fall suppression apparatus. It is a time chart explaining operation | movement of the 1st aspect of a battery voltage fall suppression apparatus. It is a figure which shows the 2nd aspect of a battery voltage fall suppression apparatus. It is a time chart explaining operation | movement of the 2nd aspect of a battery voltage fall suppression apparatus. It is a figure which shows the example of a change of the 2nd aspect of a battery voltage fall suppression apparatus. It is a figure which shows the 3rd aspect of a battery voltage fall suppression apparatus. It is a time chart explaining operation | movement of the 3rd aspect of a battery voltage fall suppression apparatus. It is a side view which shows the whole structure of the electric nail driver which concerns on 2nd Embodiment. It is sectional drawing which shows the 1st example of arrangement | positioning of a flywheel and a motor in 2nd Embodiment. It is a plane sectional view showing the 2nd example of arrangement of a flywheel and a motor in a 2nd embodiment.

Explanation of symbols

100 Electric nailing machine (Electric driving tool)
DESCRIPTION OF SYMBOLS 101 Main body part 103 Handle part 104 Trigger 105 Magazine 105a Pusher plate 107 Battery pack 110 Main body housing 111 Driver guide 111a Driving hole 113A, 113B Drive motor (1st and 2nd motor)
115A, 115B Drive pulley 117 Nail driving mechanism 121 Driver (movable body)
123 Driver support base (movable body)
124 Power transmission part 124a Power transmission surface (contact surface)
127 Contact arm 131 Drive mechanism 133A, 133B Flywheel (first and second rotating bodies)
135A, 135B Support shaft 137 Bearing 143A, 143B Driven pulley 145A, 145B Drive belt 161 Press mechanism 163 Press roller 165 Electromagnetic actuator 166 Output shaft 167 Compression spring 169 Bracket 169a Connection hole 171 Actuation arm 173 Connection shaft 175 First movable support shaft 177 Restriction arm 179 First fixed support shaft 181 Second movable support shaft 183 Press arm 185 Second fixed support shaft 191 Return mechanism 193 Return rubber 195 Take-up wheel 195a Take-up shaft 197 Stopper 197a Contact surface

Claims (7)

An electric tool comprising a movable body, a motor for driving the movable body, and a battery for supplying electric power to the motor, and machining the workpiece by driving the movable body,
As the motor, comprising a plurality of motors to simultaneously operate for jointly driving the movable member, the plurality of motors is configured so that the rotational speed is changed according to the change in the load, thereby The electric tool characterized in that the plurality of motors are configured to drive the movable body in synchronization .   The electric tool according to claim 1, wherein the plurality of motors are motors selected from a universal motor, a DC magnet motor, and a DC brushless motor, and are connected to a constant voltage power source. Electric tool to do. The electric tool according to claim 1 or 2,
An electric tool comprising: a battery voltage decrease suppressing device that suppresses a decrease in voltage of the battery during activation of the plurality of motors. The electric tool according to claim 3,
The battery voltage drop suppressing device sequentially increases the voltage applied to the motors when the plurality of motors are started. The electric tool according to claim 3,
The battery voltage drop suppression device shifts a time point at which a voltage is applied to the motors when starting the plurality of motors. The electric tool according to claim 3,
The battery voltage lowering suppression device sequentially increases the voltage applied to the motor when starting the plurality of motors, and shifts the time when the voltage is applied to the motor. The electric tool according to any one of claims 1 to 6,
The movable body is movable in a direction in which a driving material is driven into a workpiece,
First and second motors are used as the plurality of motors,
Furthermore, first and second rotating bodies that are arranged at intervals and are driven to rotate by the first and second motors, respectively,
A pressing member that presses the movable body from the direction intersecting the moving direction of the movable body toward the first and second rotating bodies;
The movable body is provided on the movable body, extends along the moving direction of the movable body, and a mutual interval becomes narrower toward the front in the direction pressed by the pressing member, and the movable body is pressed by the pressing member. First and second contact surfaces that contact the first and second rotating bodies when
When the first and second contact surfaces come into contact with the first and second rotating bodies, the movable body is moved in the direction of driving the driving material by the rotational force of the first and second rotating bodies. An electric tool characterized by that.

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