JP2022184108A - Electric tool - Google Patents

Abstract

An object of the present invention is to provide an electric power tool capable of suppressing heat generation.
A driving tool (10) having a motor (20), comprising an inverter circuit (50A) including a switching element for supplying current to the motor (20), and a drive circuit (50B) for supplying a control signal to the switching element. . Further, the driving tool 10 is configured to reduce the power supply voltage supplied to the drive circuit 50B based on the drive information.
[Selection drawing] Fig. 9

Description

The present invention relates to power tools.

The temperature of the power tool rises because it generates heat as the drive unit operates. In order to prevent damage to parts due to high temperatures, measures have been taken to notify operators that power tools are hot and prompt them to stop using them, or to forcibly prohibit the use of power tools. Teaching was taking place. By taking such measures, it becomes possible to prevent damage to the parts.

As an example of such a power tool, Patent Document 1 discloses that when the temperature of the power tool exceeds a first threshold value, the operator is notified that the power tool is hot, and when the temperature exceeds a second threshold value, the drive unit is activated. A power tool configured to forcibly stop a power tool is described. According to this power tool, since the operator is notified in advance that the power tool is hot, it is possible to avoid a situation in which the work must be suddenly interrupted.

Japanese Patent Application Laid-Open No. 2020-66116

However, in the electric power tool according to Patent Document 1, the operator who is notified that the first threshold has been exceeded is forced to slow down the work or stop the work.

As a solution different from that of Patent Document 1, it is conceivable to actively cool the power tool by connecting a fan to the motor of the power tool. However, when a fan is connected to the motor, a sufficient cooling effect cannot be obtained with an electric power tool in which the motor operates intermittently. Although it is possible to rotate the fan independently of the drive unit, an area for mounting the fan and a configuration for independently rotating the fan are required.

Accordingly, the inventors of the present application focused on suppressing the heat generation of the power tool itself as an approach different from the means for actively cooling the power tool. That is, an object of the present invention is to provide an electric power tool capable of suppressing heat generation.

The present application discloses a power tool with a motor. This power tool includes a switching element for supplying current to the motor, and a drive circuit for supplying a control signal to the switching element. Further, this power tool is configured to reduce or cut off the voltage supplied to the drive circuit based on the drive information of the power tool.

Here, "driving information" refers to information indicating the driving state of the power tool, which is obtained by driving the power tool.

Also, "reducing the voltage supplied to the drive circuit" includes supplying no voltage to the drive circuit and supplying the ground voltage to the drive circuit. The voltage includes the power supply voltage used as the power supply for the drive circuit.

A "power tool" may be a driving tool capable of driving nails, needles, pins or other fasteners.

A "motor" may be, for example, a three-phase brushless motor composed of a stator with three-phase windings and a rotor with permanent magnets.

A "switching element" may be, for example, a FET (Field Emission Transistor) or other transistor.

A power tool includes, for example, a switching circuit composed of six transistors connected in a three-phase bridge between a positive bus and a negative bus, and a stator having three-phase windings connected to the three outputs of this switching circuit. A three-phase brushless motor consisting of a rotor with permanent magnets may be provided.

The drive circuit supplies, as a control signal, a gate signal or base signal to the gate or base of a transistor, which is a switching element, for example. The control signal may be an analog signal having a voltage to cause the switching element to generate a voltage above the threshold voltage. The drive circuitry may, for example, comprise amplification circuitry for generating gate or base signals.

The power tool may further comprise a drive power supply circuit for generating a voltage to supply the drive circuit. The drive power supply circuit may include a switching element for switching between supplying and stopping the supply of voltage to the drive circuit. The switching elements may be, for example, FETs (Field Emission Transistors) or other transistors.

The power tool may further comprise control circuitry for providing control instructions to the drive circuitry. The control instructions may be digital signals. The control circuit may be, for example, a CPU (Central Processing Unit) having a processor, an ASIC (Application Specific Integrated Circuit), an LSI (Large Scale Integrated Circuit), or an SoC (System On Chip).

The control circuit of the power tool supplies a voltage to the drive circuit by, for example, supplying a control signal to the switching element of the drive power supply circuit based on the drive information of the power tool to switch ON/OFF of the switching element, or , may be controllably configured not to supply.

The power tool may be configured to separate the drive circuit and the control circuit and to supply the control circuit with the voltage of the control circuit while not supplying the voltage of the drive circuit to the drive circuit. As an example of such a configuration, the power tool may include a first semiconductor chip including a drive circuit and a second semiconductor chip including a control circuit. The power tool may include a package (enclosure) that seals the first semiconductor chip and the second semiconductor chip.

The power tool may be configured such that the voltage of the drive circuit is greater than the voltage of the control circuit.

The driving information of the power tool may include information indicating the temperature of the power tool.

The power tool may include, for example, a temperature sensor for acquiring information indicating the temperature of the second semiconductor chip as information indicating the temperature of the power tool. This temperature sensor may be further sealed with a package (enclosure) that seals the first semiconductor chip and the second semiconductor chip. At this time, the power tool includes a first semiconductor chip including a drive circuit, a second semiconductor chip including a control circuit, a temperature sensor for acquiring information indicating temperatures of the control circuit and providing the information to the control circuit, and the first semiconductor chip. , a package (enclosure) for sealing the second semiconductor chip and the temperature sensor.

Alternatively, the power tool may comprise a temperature sensor for obtaining information indicating the temperature of the motor or the switching circuit, for example, as the information indicating the temperature of the power tool. This temperature sensor may be a thermistor connected to a switching circuit. The temperature sensor may be installed on a board on which a control circuit or the like is mounted, or may be installed inside the power tool body.

The driving information of the electric power tool may include information indicating an operation time of a driving unit provided in the electric power tool. Since the operating time of the drive unit has a correlation with the temperature of the power tool, heat generation can also be suppressed by reducing the voltage supplied to the drive circuit based on the information indicating the operating time of the drive unit. It becomes possible.

As used herein, the term "driving section" refers to a portion of the power tool that is driven. When the power tool is a driving tool, the drive section includes a motor that drives rotation. Parts driven by a motor may be included in the driving section.

When the power tool is a driving tool, the operation time of the driving part may be the operation time of the motor or the operation time of the plunger driven by the motor. The total time required to return to the standby point may be used as the operating time of the drive unit. For example, if the average operating time of the driving unit for driving one fastener is 100 msec, and 1000 fasteners are driven after starting driving, the operating time of the driving unit is 1000 x 100 msec. Therefore, it is 100 seconds.

The driving information of the electric power tool may include information indicating the number of times a driving unit provided in the electric power tool is operated per unit time. Since the number of operations of the drive unit per unit time is correlated with the temperature of the power tool, the voltage supplied to the drive circuit is reduced based on the information indicating the number of operations of the drive unit per unit time. This also makes it possible to suppress heat generation.

When the power tool is a driving tool, the number of operations of the drive unit per unit time may be the number of times the fastener is driven per unit time. For example, if the number of fasteners driven per minute is 50, the number of operations per unit time of the drive section is 50 times/minute.

The driving information of the power tool may include information indicating the temperature of the motor.
The driving information of the power tool may include current information of the motor.

A voltage supplied to the drive circuit may be reduced based on drive information of the power tool when the power tool is in a standby state.

Here, the stand-by state of the power tool refers to a state in which the driving portion of the power tool is not operating. When the driving portion of the power tool includes a motor, the standby state of the power tool may correspond to a state in which the motor is not rotating.

For example, in the case of an electric power tool having a trigger as an operation unit and an operator operating the operation unit, that is, in the case of an electric tool in which the motor starts rotating when the trigger is pulled, the operator pulls the trigger and the motor starts rotating. In some cases, the electric power tool is configured such that the state from when the motor is started and then when the motor is stopped until the operator next pulls the trigger is the standby state of the electric power tool.

When the power tool is a driving tool, the stand-by state of the power tool means that the operator operates the operation part (pulls the trigger) to start rotating the motor and move the plunger waiting at the stand-by position. The power tool may be configured to transition from the active state to the standby state when the plunger returns to the standby position and the motor stops after driving the fastener. The standby state continues until the operator next pulls the trigger.

For example, if the number of times a fastener is driven is 50 times per minute, and the average value of the operating time of the drive unit for driving one fastener is 100 ms, the operating time per minute is 5 seconds, The time in the standby state (hereinafter sometimes referred to as "waiting time") is 55 seconds.

The inventors of the present application paid attention to the waiting state that occurs in the gap (typically less than 1 second) in which the fasteners are continuously driven, and decided to reduce the voltage supplied to the drive circuit by capturing this timing. conceived.

In addition, the power tool may comprise means for detecting the standby state of the power tool. When the main driving part of the power tool is a motor, means for detecting the standby state of the power tool may be a sensor such as a Hall element for detecting the rotational speed of the motor. Alternatively, the means for detecting the standby state of the power tool may be a control circuit for controlling the motor. The control circuit detects that the power tool has transitioned from the operating state to the standby state based on the elapse of the time required for stopping the rotation of the motor from the start of brake control (stop control) for stopping the rotation of the motor. It may be configured to detect that

The present application discloses a driving tool with a motor. The driving tool includes a switching element for supplying current to the motor, and a drive circuit for supplying a control signal to the switching element. This driving tool is configured to be able to repeatedly perform an operating state in which the drive section operates to drive the fastener and a standby state in which the drive section waits. During the operating state, a voltage is applied to the drive circuit. and configured to include the time during which the reduced voltage is supplied (including no voltage supplied) to the drive circuit when in a standby state.

The driving tool may be configured to drive fasteners at least 30 times per minute. The driving tool is then configured to include at least 29 standby states per minute, each of which includes a period of time during which the drive circuit is supplied with a reduced voltage (including no voltage). . Each wait time may be less than 1 second. The driving tool may be configured such that the time per unit time that the drive circuit is supplied with the reduced voltage is greater than the time that the drive circuit is supplied with the unreduced voltage.

A threshold for reducing the voltage may be settable.

The threshold value may be a value given to information indicating the temperature of the power tool.

The driving tool is in a standby state in which the driving unit is on standby, and when the temperature of the power tool is lower than a threshold value, a voltage that is not reduced is supplied to the drive circuit and the driving unit is on standby, and , a time during which a reduced voltage is supplied (including no voltage is supplied) to the drive circuit when the temperature of the power tool is greater than a threshold.

A notification means may be further provided for notifying that the voltage supplied to the drive circuit has been reduced or cut off. The notification means may be any means that can be perceived by the operator, and may be, for example, visual notification means such as an LED light, or auditory notification means such as a buzzer.

The power tool may be configured to stop driving when the temperature of the power tool reaches a predetermined value. When the threshold is a value assigned to the information indicating the temperature of the power tool, the predetermined value may be a value greater than the threshold.

The present application discloses a power tool with a motor. This power tool includes a switching element for supplying current to the motor, a drive circuit for supplying a control signal to the switching element, a control circuit for supplying a control command to the drive circuit, and an operator. and an operation unit (trigger) configured to be operable. In this power tool, when the operation unit is operated in a state in which the first voltage is supplied to the control circuit and the second voltage is supplied to the drive circuit, the switching element causes the motor to start rotating. a first operation mode in which the supply of the second voltage to the drive circuit is not stopped after the motor stops rotating; and a first voltage is supplied to the control circuit and a second voltage is supplied to the drive circuit. When the operation unit is operated in a state in which the second voltage is not applied, the second voltage is supplied to the drive circuit, the motor starts to rotate by the switching element, and after the motor stops rotating, the voltage is applied to the drive circuit. and a second operation mode for stopping the supply of the second voltage.

The first operating mode is configured to be executable when the temperature of the electric power tool is lower than the first temperature, and the second operating mode is configured to be executable when the electric power tool is at a second temperature higher than the first temperature. you can

The power tool is a driving tool for driving a fastener, and the first time required from the operation of the operation section to driving the fastener in the first operation mode is equal to the operation of the operation section in the second operation mode. The power tool may be configured to be shorter than the second time required from to driving the fastener.
The present application discloses a power tool with a motor. This electric power tool is a control circuit for controlling the motor, and when the driving information of the electric power tool satisfies a preset condition and the electric power tool is in a standby state, it executes its own control processing. a control circuit configured to partially limit the

FIG. 1 is a front view of a driving tool according to one embodiment. FIG. 2 is a cross-sectional view of a driving tool according to one embodiment. 3 is a perspective view of a plunger assembly according to one embodiment; FIG. FIG. 4 is a cross-sectional view (front view) of a plunger assembly according to one embodiment. FIG. 5 is a cross-sectional view (side view) of a plunger assembly according to one embodiment. FIG. 6 is a cross-sectional view (plan view) of a plunger assembly according to one embodiment. FIG. 7 is a perspective view including a plunger and wire according to one embodiment. FIG. 8 is a control block diagram of the driving tool according to one embodiment. FIG. 9 is a timing chart showing the power supply state of the driving tool according to one embodiment. FIG. 10 is a flowchart of a driving method using a driving tool according to one embodiment. FIG. 11 is a graph showing temperature changes of a driving tool according to one embodiment.

An embodiment of the present invention will be described below with reference to the drawings. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention only to those embodiments.

[First embodiment]
FIG. 1 shows a front view of an electric driving tool 10 according to the first embodiment (however, a partial sectional view of the magazine portion is shown), and FIG. 2 shows a driving tool viewed from the same direction. A cross-sectional view of the tool 10 is shown (but shown after all the fasteners F in the magazine 14 have been driven out).

The driving tool 10 is an electric nailer configured to drive a nail (an example of a "fastener F") by driving a plunger 32 (FIG. 2) using a motor (FIG. 2). . It should be noted that "up and down", "back and forth", and "left and right" in this specification are based on the posture of the driving tool 10 shown in FIGS. 1 and 2 . 1 and 2 corresponds to the direction in which the fastener F is driven out, and is sometimes referred to as the driving direction DR1 or the injection direction DR1. Since it is the direction away from 12A, it may be called the away direction DR2. Directions may be expressed using direction X1, direction X2, direction Y, and direction Z as indicated in the drawings.

The driving tool 10 includes a housing 12, a magazine 14 for accommodating fasteners F to be driven out by the driving tool 10, a driver 34 for driving out the fasteners F, a plunger 32 to which the driver 34 is attached, and a plunger 32 downward. A motor 20 and a gear 22 for moving the plunger 32 from the top dead center to the bottom dead center, and a coil spring 36 (“biasing member” or “driving member”) for applying a driving force for moving the plunger 32 from the top dead center to the bottom dead center. an example of a "means"), a moving member 38 disposed at the extending end of the coil spring 36, and a wire 40 (an example of a "string-like member") that engages with the plunger 32 and the moving member 38 and interlocks them. , and a pulley 42 (an example of a “direction changing member”) on which a wire 40 is wound. Furthermore, the driving tool 10 is detachably provided with a battery B. As shown in FIG.

The driving tool 10 includes a housing 12 (hereinafter, the housing 12 and the portion fixed to the housing 12 may be referred to as a "tool main body") that houses main parts of the driving tool 10 including the plunger 32. As shown in FIG. The housing 12 is provided with a grip portion 12B to be gripped by the operator, a bridging portion 12C connecting the motor 20 to the battery attachment portion on which the battery B is attached, and a nose portion 12D for driving out the fastener F. The grip portion 12B and the bridging portion 12C are each formed, for example, in a columnar shape extending in the vertical direction so that the operator can easily grip them. The front end of the housing 12 (and the front end of the driving tool 10) is provided with a nose portion 12D having an ejection opening 12A for driving out the fastener F leftward on the paper surface. A contact arm 12D1 may be attached to the tip of the nose portion 12D. The contact arm 12D1 is provided around the ejection port 12A so as to be retractable from the ejection port 12A. It functions as a safety device that permits hammering out of the fastener F.

The housing 12 is provided with a trigger 12E (an example of an “operation unit”). The trigger 12E brings the battery B and the motor 20 into conduction when pressed by the user. The trigger 12E is provided exposed on the surface of the grip portion 12B facing forward (the driving direction DR1 of the fastener F), and is biased forward (the driving direction DR1) by a trigger biasing member 12F such as a spring. there is

The battery B is detachably attachable to the lower ends of the grip portion 12B and the bridge portion 12C. The battery B functions as a DC power supply that supplies electric power for driving a motor or the like, and can output a predetermined DC voltage (for example, 14 V to 20 V, and 18 V in this embodiment). It consists of an ion battery. By attaching a battery B, the driving tool 10 can be carried and used. However, the battery B may be housed in the housing 12, or power may be supplied by means other than the battery.

The driving tool 10 has a magazine 14 attached below the nose portion 12D. The magazine 14 is configured to be loaded with a plurality of connected fasteners F (FIG. 1). The magazine 14 includes a pusher 14A that biases the fastener F toward the nose portion 12D. The pusher 14A is biased by a biasing member (not shown) so that when the leading fastener F is driven out by the driver 34, the adjacent fastener F is supplied to the ejection path of the nose portion 12D.

Driving tool 10 further includes a plunger assembly 30 . FIG. 3 is a perspective view of the plunger assembly 30, and FIGS. 4 and 5 show a state in which the coil spring 36 is most compressed (an example of a "first state") and a state in which the coil spring 36 is most stretched (an example of a "second state"). ) is a sectional view of the plunger assembly 30 (if FIG. 4 is a sectional view in a front view, FIG. 5 corresponds to a sectional view in a left side view). FIG. 6 shows a cross-sectional view of plunger assembly 30 in plan view. FIG. 7 is a perspective view showing plunger 32, pin 38A that is part of moving member 38, and wire 40 that engages plunger 32 and moving member 38. FIG. The plunger assembly 30 includes a driver 34, a plunger 32, a coil spring 36, a moving member 38, a wire 40 and a pulley 42, a cylinder 44 that houses the coil spring 36, and a pair of guide rails that regulate the direction of movement of the plunger 32. 46.

The driver 34 is a member that drives out the fastener F by coming into contact with the fastener F and hitting it. As shown in these drawings, the driver 34 according to the present embodiment is composed of a metal rigid body shaped like an elongated rod extending in the direction DR1 of driving out the fastener F. As shown in FIG. Since the fastener F is arranged on the extension line of the driver 34, the front end of the driver 34 hits the fastener F when the driver 34 moves in the driving direction DR1. A rear end of the driver 34 is connected to the plunger 32 and configured to move integrally therewith.

The plunger 32 is a member for driving out the fastener F by moving integrally with the driver 34 by moving from the top dead center to the bottom dead center. As shown in FIG. 7, the plunger 32 has four side walls, a first side wall 32A with which the wire 40 engages, and a first side wall 32A connected substantially perpendicularly to the first side wall 32A and engaged with the guide rail 46. a second side wall portion 32B that is aligned with the second side wall portion 32B; a third side wall portion 32C that is connected to the second side wall portion 32B at a substantially right angle and is provided substantially parallel to the first side wall portion 32A; and a fourth side wall portion 32D that is connected to the first side wall portion 32A at a substantially right angle, is provided substantially parallel to the second side wall portion 32B, and engages with the guide rail 46. As shown in FIG. A cylinder 44, which will be described later, is arranged in a hollow area surrounded by four side walls. The outer wall surface of the first side wall portion 32A is provided with gear engaging portions 32A1, which are two convex portions provided at different heights, and the gear engaging portions 32A1 are engaged with the gear 22 described later. By doing so, the plunger 32 is configured to move from the bottom dead center toward the top dead center against the elastic force (urging force) of the coil spring 36 . Here, the top dead center of the plunger 32 is set in the region on the rear end side of the tool body, and the bottom dead center is set in the region between the top dead center and the nose portion 12D. Therefore, when the plunger 32 moves from the top dead center to the bottom dead center, the plunger 32 moves in the ejection direction DR1 approaching the injection port 12A, and when the plunger 32 moves from the bottom dead center to the top dead center, The plunger 32 moves in a separation direction DR2 away from injection.

The first side wall portion 32A of the plunger 32 is further provided with a wire engaging portion 32A2. The wire engaging portion 32A2 is formed by a first portion 32A21 projecting inward from the inner wall surface of the first side wall portion 32A (that is, a direction approaching the third side wall portion 32C) and an end of the first portion 32A21. It has a second portion 32A22 extending in a direction approaching the top dead center. The surface facing the top dead center of the first portion 32A21 serves as a pressure receiving surface for applying force from the wire 40 to the plunger 32 in the ejection direction DR1. In addition, the second portion 32A22 restricts the wire 40 from shifting in the direction of approaching the third wall. Furthermore, since the first portion 32A21 is formed to protrude in a direction approaching the third side wall portion 32C, the wire 40 engaged with the pressure receiving surface of the first portion 32A21 extends along the inner wall surface of the first side wall portion 32A. It is possible to exist. Therefore, it is also possible to suppress the wire 40 from shifting in the direction away from the third side wall portion 32C. In addition, the wire engaging portion 32A2 is formed symmetrically with respect to a virtual plane IP1 (FIG. 6) that is parallel to the planes approximating the second side wall portion 32B and the fourth side wall portion 32D and is equidistant from both planes. ing. With this configuration, it is possible to prevent the plunger 32 from tilting due to imbalance in the force acting on the plunger 32 from the wire 40 .

The second side wall portion 32B and the fourth side wall portion 32D are formed symmetrically with respect to the virtual plane IP1. The second side wall portion 32B and the fourth side wall portion 32D are provided with guide rollers 32B1 and 32D1 for engaging with the guide rail 46, respectively. Since two guide rollers 32B1 and 32D1 are provided on the top dead center side and the bottom dead center side respectively, the plunger 32 is tilted during movement by engaging each of the two guide rollers 32B1 and 32D1 with the guide rail 46. can be suppressed.

The third side wall portion 32C is provided with a driver engagement portion 32C1 formed symmetrically with respect to the virtual plane IP1 and to which the rear end of the driver 34 is connected. Therefore, it is possible to prevent the plunger 32 from tilting due to the reaction force that the plunger 32 receives when the driver 34 strikes the fastener F.

As shown in these drawings, when the moving direction of the plunger 32 (the direction connecting the top dead center and the bottom dead center) is used as a reference, the distance between the driver engaging portion 32C1 and the injection port 12A is The plunger 32 is configured to be smaller than the distance between the joining portion 32A2 and the injection port 12A.

The cylinder 44 is a member that accommodates the coil spring 36 and guides the movement direction of the pin 38A forming a part of the moving member 38 . The cylinder 44 according to this embodiment includes a cylindrical portion 44A formed in a cylindrical shape and a cap portion 44C corresponding to a lid of the cylindrical portion 44A. The cylinder 44 passes through a hollow area surrounded by the four side walls of the plunger 32, is fixed to the housing 12 so that the moving direction of the plunger 32 and the central axis of the cylinder 44 are substantially parallel, and has a cap portion 44C. fix the guide rail 46 .

Inside the cylinder 44, a coil spring 36 made of a compression spring that can expand and contract in the central axis direction of the cylinder 44, that is, in the moving direction of the plunger 32 is accommodated. One end 36A of the coil spring 36 is fixed to the bottom surface of the cylinder on the injection port side (bottom dead center side of the plunger 32). A moving member 38 is arranged at the other end 36B of the coil spring 36 , and tension is applied to the moving member 38 by a wire 40 toward the one end 36A of the coil spring 36 . Therefore, both the other end 36B of the coil spring and the moving member 38 are movable, and when the coil spring 36 is compressed from the expanded state, the other end 36B of the coil spring and the moving member 38 move in the launch direction DR1, and the coil spring When the coil spring 36 expands and restores from the compressed state, the other end 36B of the coil spring and the moving member 38 move in the separation direction DR2 away from the injection port 12A. A wall portion of the cylinder 44 is formed with a pair of holes 44B extending parallel to the central axis, that is, parallel to the extension direction of the coil spring 36 .

The moving member 38 directly or indirectly engages a portion of the wire 40 to move the wire 40 with the extension of the other end 36B of the coil spring. The moving member 38 according to this embodiment includes an annular portion 38B arranged at the other end 36B of the coil spring, and a pin 38A fixed to the annular portion 38B and engaged with both ends of the wire 40 . In this embodiment, the pair of holes 44B formed in the wall of the cylinder 44 are parallel to two planes approximating the first side wall 32A and the third side wall 32C of the plunger 32, and the cylinder 44 and the coil spring 36 are aligned. is formed to intersect with a virtual plane IP2 (FIG. 6) passing through the central axis of. Both ends of the pin 38A are engaged with the pair of holes 44B so that the extending direction of the pin 38A is substantially parallel to the imaginary plane. Therefore, even if the moving member 38 including the pin 38A moves in the central axis direction of the cylinder 44 as the coil spring 36 expands or compresses, twisting of the pin 38A in the circumferential direction of the cylinder 44 can be suppressed. becomes possible.

The wire 40 is a member that links the moving member 38 and the plunger 32 by being attached to the moving member 38 and the plunger 32 . In this embodiment, the wire 40 is formed in a ring shape by connecting one end of the wire 40 and a portion spaced from the end of the wire 40 at one end, and the ring-shaped portion is passed through. Pin 38A thereby engages wire 40. As shown in FIG. A wire 40 engaged with the pin 38A passes through a hole in the annular portion 38B of the moving member 38, extends in the driving direction DR1 along the central axis of the coil spring 36, and extends through a hole formed in the bottom surface of the cylinder 44. , the plunger 32 changes its direction by being wound around the pulley 42, extends in the separating direction DR2, and engages with the pressure receiving surface of the wire engaging portion 32A2 of the plunger 32. As shown in FIG. Subsequently, the wire 40 extends in the driving direction DR<b>1 , changes direction by being looped around the pulley 42 , and extends in the separating direction DR<b>2 along the central axis of the coil spring 36 . The other end of the wire 40 is formed into a loop shape by connecting the other end of the wire 40 and a portion spaced from the end of the wire 40, and a pin is formed by penetrating the loop-shaped portion. 38A engages wire 40; Thus, both ends of wire 40 engage pin 38A and the middle portion of wire 40 engages plunger 32. FIG.

That is, the wire 40 includes a first portion 40A including one end portion that engages with the moving member 38, a second portion 40B including a portion connected to the first portion 40A and extending in the driving direction DR1, and a second portion 40B. A third portion 40C including a portion connected and extending substantially in the separation direction, a fourth portion 40D connected to the third portion 40C and engaged with the plunger 32, and a portion connected to the fourth portion 40D and extending substantially in the ejection direction DR1. a sixth portion 40F including a portion connected to the fifth portion 40E and extending in the separating direction DR2; and the other end connected to the sixth portion 40F and engaged with the moving member 38. and a seventh portion 40G including a portion.

A drive mechanism for moving the plunger 32 from the bottom dead center to the top dead center is composed of a motor 20 and a gear 22 . The motor 20 according to the present embodiment shown in FIG. 2 is composed of a three-phase DC brushless motor. are arranged so that A first gear 22A that constitutes the gear 22 and a gear whose rotation axis is the output shaft of the motor 20 are meshed, and the first gear 22A is meshed with a second gear 22B that constitutes the gear 22. FIG. The first gear 22A is arranged in the separation direction DR2 with respect to the gear of the output shaft of the motor 20, and the second gear 22B is arranged in the separation direction DR2 with respect to the first gear 22A. Each of the first gear 22A and the second gear 22B is provided with a torque roller (not shown) that is parallel to the rotation axis and protrudes in a direction approaching the outer wall surface of the first side wall portion 32A of the plunger 32 . The torque roller rotates around the central axis of the first gear 22A (second gear 22B) as the first gear 22A (second gear 22B) rotates. Since the central axis of the first gear 22A (second gear 22B) is parallel to the output shaft of the motor 20, the torque roller moves in the launch direction DR1 and away from the torque roller as the first gear 22A (second gear 22B) rotates. It reciprocates in direction DR2. When the plunger 32 exists in the vicinity of the bottom dead center, the torque roller of the first gear 22A engages with one convex portion provided on the bottom dead center side as the gear engaging portion 32A1. Since the torque roller moves in the separating direction DR2 as the first gear 22A rotates, the gear engaging portion 32A1 of the plunger 32 is pushed up in the separating direction DR2, so that the plunger 32 can be moved in the separating direction DR2. . When the torque roller of the first gear 22A moves most in the separating direction DR2, the torque roller of the second gear 22B engages with the other convex portion provided on the top dead center side as the gear engaging portion 32A1. Since the torque roller moves in the separating direction DR2 with the rotation of the second gear 22B, the gear engaging portion 32A1 of the plunger 32 is further pushed up in the separating direction DR2, so that the plunger 32 can be further moved in the separating direction DR2. becomes. When the torque roller of the second gear 22B moves most in the separating direction DR2, the plunger 32 reaches the top dead center and the engagement between the gear engaging portion 32A1 and the second gear 22B is released. .

The driving tool 10 further comprises a control unit 50 for driving the motor 20 . The controller 50 is mounted on the PCB board 24 (FIG. 2) arranged in the gap between the motor 20 and the battery B in the bridge section 12C.

FIG. 8 shows a functional block diagram of the driving tool 10. As shown in FIG. The motor 20 to be controlled by the control unit 50 includes a rotor and a stator having three-phase windings (an example of "stator windings"). The motor 20 is configured to rotate a rotor having permanent magnets by supplying a three-phase alternating current to three-phase windings based on a DC power supply voltage supplied from the battery B to generate a rotating magnetic field. It is a phase brushless motor. Note that the motor 20 is not provided with a position detection sensor such as a Hall IC for detecting the position of the rotor of the motor 20 . However, the motor 20 may be provided with a position detection sensor for detecting the position of the rotor.

The control unit 50 includes an inverter circuit 50A including switching elements for supplying three-phase alternating current to the three-phase windings of the motor 20, a drive circuit 50B for supplying control signals to the switching elements of the inverter circuit 50A, A drive power supply circuit 50C for generating a power supply voltage for operating the drive circuit 50B and supplying it to the drive circuit 50B, a control circuit 50D for supplying a control command to the drive circuit 50B, and a control circuit 50D for operating the control circuit 50D. and a sensor 50S for acquiring drive information of the driving tool 10.

The inverter circuit 50A is, for example, a FET (Field Effect Transistor) or IGBT, which is three-phase bridge-connected between a positive bus line (power line) and a negative bus line (ground line) connected to the output terminal of the battery B. (Insulated Gate Bipolar Transistor) or other power transistors, and freewheel diodes connected in parallel to the switching elements. Three output terminals of this inverter circuit are connected to the three-phase windings of the stator of the motor 20, respectively. Therefore, by turning ON/OFF the six switching elements, the inverter circuit 50A is configured to generate a voltage between the three-phase windings and supply a current.

The drive circuit 50B supplies gate signals or base signals as control signals to the gates or bases of six power transistors, which are switching elements. The drive circuit 50B according to the present embodiment uses a DC voltage of 12V (an example of a “second power supply voltage”) supplied from the drive power supply circuit 50C based on a control command received from the control circuit 50D to switch the switching element. An analog signal having a voltage that causes the switching element to conduct by generating a voltage exceeding the threshold voltage therein is generated as a control signal and supplied to the switching element. The drive circuit 50B has an amplifier circuit for generating a gate signal or base signal. In this embodiment, the drive circuit 50B is composed of a one-chip semiconductor substrate (semiconductor die). One chip on which the drive circuit 50B is formed may be called a first semiconductor chip. However, this does not prevent the drive circuit 50B from being constructed from a plurality of semiconductor substrates.

The drive power supply circuit 50C generates, for example, a DC voltage of 12V as a power supply voltage for operating the drive circuit 50B based on the power supply voltage supplied from the battery B, and supplies the drive circuit 50B with the DC voltage. The drive power supply circuit 50C includes an ON/OFF circuit 50C1 for switching between supplying and stopping supply of the power supply voltage to the drive circuit 50B based on a control command (ON/OFF command) from the control circuit 50D. The ON/OFF circuit 50C1 has a switching element composed of a transistor. Therefore, when the ON/OFF circuit 50C1 is ON and the switching element is conducting, the drive power supply circuit 50C supplies a power supply voltage of 12V to the drive circuit 50B, and the ON/OFF circuit 50C1 is OFF and the switching element is conducting. When not, the drive power supply circuit 50C does not supply the power supply voltage of 12V to the drive circuit 50B.

The control circuit 50D supplies the drive circuit 50B with a control instruction for causing the drive circuit 50B to generate a control signal for controlling the six power transistors, which are switching elements. The control circuit 50D according to the present embodiment generates PWM (Pulse Width Modulation), which is a digital signal, based on, for example, a DC voltage of 5 V or less (an example of a “first power supply voltage”) supplied from the system power supply circuit 50E. ) signal as a control command (driving command) and supplied to the drive circuit 50B. By configuring the drive circuit 50B and the control circuit 50D so that the first power supply voltage is lower than the second power supply voltage, the effect of suppressing heat generation can be increased.

Furthermore, the control circuit 50D generates a control signal (ON/OFF command) for controlling the switching element of the ON/OFF circuit 50C1 based on, for example, a DC voltage of 5 V supplied from the system power supply circuit 50E, and turns ON the ON/OFF command. /OFF circuit 50C1.

As a hardware configuration, the control circuit 50D stores a part of the computer program for controlling the driving tool 10 including the arithmetic processing described in the present embodiment, the control program for the motor 20, etc., and data such as the result of the arithmetic processing. , a volatile semiconductor memory (SRAM) for temporary storage, and a processor for executing the computer program described above and generating control instructions including drive instructions, ON/OFF instructions, etc. It is implemented as a CPU configured from a semiconductor substrate (semiconductor die). One chip on which the CPU of the control circuit 50D is formed may be called a second semiconductor chip.

Since the drive circuit 50B and the control circuit 50D are provided as different chips in this way, while the power supply voltage is supplied from the system power supply circuit 50E to the control circuit 50D, the control circuit 50D is used to supply the power supply voltage from the drive power supply circuit 50C to the drive circuit 50B. It is possible to easily implement a configuration for stopping the supply of the power supply voltage to the . However, this does not prevent the CPU from being composed of a plurality of semiconductor substrates.

The driving tool 10 further includes a multi-chip package (perimeter) having resin for sealing a plurality of chips constituting the drive circuit 50B, the CPU of the control circuit 50D, and the sensor 50S, which will be described later. That is, by sealing the CPUs of the drive circuit 50B and the control circuit 50D in the same package, the control section 50 can be provided compactly. In addition, while adopting a structure sealed in the same package, the power supply voltage is supplied to the CPU of the control circuit 50D, while a reduced voltage is supplied to the drive circuit 50B (including not supplying the power supply voltage). By adopting the configuration, it is possible to suppress the heat generation of the drive circuit 50B and the transmission of this heat to the CPU of the control circuit 50D. In addition to the above, the package may include the drive power supply circuit 50C, the ON/OFF circuit 50C1 and the system power supply circuit 50E.

The control circuit 50D further includes a semiconductor memory such as a flash memory for non-transitory storage of the above-described computer program and supplying it to the CPU of the control circuit 50D, and a semiconductor memory such as a DRAM functioning as a main memory. and

The control circuit 50D having the above configuration supplies a control signal to the switching element included in the ON/OFF circuit 50C1 of the drive power supply circuit 50C based on driving information of the driving tool 10 acquired from the sensor 50S described later (or By switching ON/OFF of the switching element (stopping the supply of the control signal), the power supply voltage is supplied to the drive circuit 50B, or the supply is stopped (not supplied). there is However, the control circuit 50D is configured to be controllable to supply a voltage (eg, 5V) lower than the power supply voltage (eg, 12V) for operating the drive circuit 50B based on the drive information of the driving tool 10. may Even with a configuration that supplies a reduced voltage, it is possible to suppress heat generation caused by the drive circuit 50B.

The system power supply circuit 50E generates a DC voltage of, for example, 5V or less as a power supply voltage for operating the control circuit 50D based on the power supply voltage supplied from the battery B, and supplies the DC voltage to the control circuit 50D. Since both the drive power supply circuit 50C and the system power supply circuit 50E are voltage generation circuits, they may share some circuits or may be configured from one chip.

The sensor 50S acquires information indicating the driving state of the driving tool 10, which is acquired by driving the driving tool 10, and supplies the information to the control circuit 50D. The sensor 50</b>S according to this embodiment is a temperature sensor that acquires information indicating the temperature of the driving tool 10 . The temperature of the driving tool 10 rises when the driving tool 10 is continuously operated and decreases when the continuous operation is stopped.

In this embodiment, the sensor 50S is composed of a temperature sensor such as a thermistor arranged close to the control circuit 50D or a DTS (Digital Thermal Sensor) incorporated in the semiconductor substrate constituting the CPU of the control circuit 50D. Therefore, the sensor 50S can accurately acquire the temperature of the CPU of the control circuit 50D. For this reason, when a power tool whose temperature rise in the control circuit is a problem (for example, when the power tool is operated continuously, the timing at which the temperature of the CPU in the control circuit reaches the rated temperature (for example, the maximum junction temperature) of the CPU is delayed. , electric tools that may reach the rated temperature of other parts earlier than the timing of reaching the rated temperature of the parts), it is possible to suppress the heat generation of the electric tools with high accuracy. The inventors of the present application paid attention to the fact that the CPU of the control circuit instead of the motor may be the problematic component when the power tool is operated continuously. A structure (for example, a structure in which the sensor 50S is provided in the same package) is adopted. However, the present invention is not limited to this, and the sensor 50S may be a thermistor or other temperature sensor installed near the switching element of the motor 20 or the inverter circuit 50A. In this case, the sensor 50S can accurately acquire the temperature of the motor 20 or the like. With such a configuration, it is possible to suppress the possibility of the stator windings of the motor 20 being short-circuited or the motor 20 being burnt out.

In the above configuration, the control section 50 is configured to be able to drive the driving tool 10 in at least two operation modes using the control circuit 50D. 9A and 9B show the power supply voltage (system power supply) supplied to the control circuit 50D and the power supply voltage supplied to the drive circuit 50B in the first operation mode and the second operation mode of the driving tool 10. 3 is a timing chart showing the operation state of a trigger 12E (driver power source) and the drive state of a motor 20. FIG.

As shown in FIG. 9A, in the first operation mode, the power supply voltage for operating the control circuit is continuously supplied from the system power supply circuit 50E to the control circuit 50D, and the power supply voltage for operating the control circuit is supplied from the drive power supply circuit 50C to the drive circuit 50B. In this operation mode, continuous operation of driving a plurality of fasteners F can be executed while continuously supplying the power supply voltage for the operation of the drive circuit. When the control circuit 50D detects that the operator has operated the trigger 12E to drive the fastener F in the first operation mode, the control circuit 50D supplies a control command for controlling the motor 20 to the drive circuit 50B. Therefore, the motor 20 starts rotating (A in FIG. 9A), and the driving tool 10 is put into an operating state. Even after the motor 20 stops rotating after the fastener F is driven in and the driving tool 10 transitions from the operating state to the standby state, power supply voltage is supplied from the system power supply circuit 50E to the control circuit 50D and from the drive power supply circuit 50C. The supply of the power supply voltage to the drive circuit 50B continues.

As shown in FIG. 9B, in the second operation mode, the power supply voltage for operating the control circuit is continuously supplied from the system power supply circuit 50E to the control circuit 50D, while the drive power supply circuit 50C supplies the drive circuit 50B. In this operation mode, a continuous operation of driving a plurality of fasteners F can be executed while intermittently (intermittently) supplying a power supply voltage for operating the drive circuit. When the control circuit 50D detects that the operator has operated the trigger 12E to drive the fastener F in the second operation mode, the control circuit 50D controls the switching element of the ON/OFF circuit 50C1 to ON. A signal is supplied to the ON/OFF circuit 50C1. As a result, the drive power supply circuit 50C starts supplying the drive circuit 50B with the power supply voltage for operating the drive circuit (B in FIG. 9B). After that, the control circuit 50D supplies a control command for controlling the motor 20 to the drive circuit 50B, so that the motor 20 starts rotating (C in FIG. 9(B)), and the driving tool 10 becomes operative. When the motor 20 stops rotating after the completion of driving and the driving tool 10 transitions from the operating state to the standby state, the control circuit 50D turns ON the switching element of the ON/OFF circuit 50C1 to control the switching element to OFF. The supply of the control signal for control is stopped. As a result, the supply of power supply voltage from the system power supply circuit 50E to the control circuit 50D continues, while the supply of power supply voltage from the drive power supply circuit 50C to the drive circuit 50B stops (D in FIG. 9B). After that, when the operator again operates the trigger 12E to drive the fastener F, the drive power supply circuit 50C starts to supply the drive circuit 50B with the power supply voltage for driving the drive circuit 50B. Similar steps are performed thereafter.

Here, as means for the control circuit 50D to detect that the motor 20 has stopped rotating after driving and the driving tool 10 has transitioned to the standby state, the control unit 50 performs brake control for stopping the rotation of the motor 20. A counter that starts counting when (stop control) is started may be provided. Since the time assumed to be required from the start of brake control to the stop of rotation of the motor 20 is known, the control unit 50 determines the elapsed time required to stop the rotation of the motor 20 based on the count value of the counter. By judging whether or not, it is possible to accurately detect that the driving tool 10 has transitioned from the operating state to the standby state.

Instead of this, the control unit 50 detects that the driving tool 10 has transitioned from the operating state to the standby state based on other timing, such as counting the time required from the start of driving to the completion of driving. may be configured. As still another means, it is determined that the rotation of the motor has stopped and that the driving tool 10 has transitioned from the operating state to the standby state based on a signal obtained from a sensor such as a hall element for detecting the rotational speed of the motor. may be configured to detect. Alternatively, it may be configured to detect the stoppage of rotation of the motor and the transition of the driving tool 10 from the operating state to the standby state based on the back electromotive force or the like generated in the stator windings.

The control circuit 50D of the driving tool 10 according to the present embodiment is configured to switch between the first operation mode and the second operation mode based on driving information of the driving tool 10 acquired from the sensor 50S. . Specifically, the sensor 50S installed near the CPU of the control circuit 50D supplies information indicating the temperature of the driving tool 10 to the control circuit 50D. If the estimated temperature of the driving tool 10 is less than the predetermined first threshold, the control circuit 50D operates the driving tool 10 in the first operation mode, and the temperature is estimated based on the information obtained from the sensor 50S. When the temperature of the driving tool 10 is greater than or equal to a predetermined first threshold value and less than a second threshold value, the control circuit 50D operates the driving tool 10 in the second operation mode, and estimates based on the information acquired from the sensor 50S. The control circuit 50D is configured to stop operation of the driving tool 10 when the temperature of the driving tool 10 being driven reaches a second threshold. The temperature or the like of the driving tool 10 to be compared with the first threshold or the like is not limited to a value indicating the actual temperature of the driving tool 10, and may be a value that varies according to the temperature of the driving tool 10. Just do it. For example, the driving tool 10 may be configured to compare the value obtained from the sensor 50S with the first threshold or the like without converting it into the temperature of the driving tool 10 .

A driving method using the driving tool 10 according to the present embodiment will be described below. FIG. 10 is a flow chart showing the implantation method. FIG. 11 is a graph showing temperature changes of the driving tool 10 during continuous operation.

First, when the operator turns on the main power switch of the driving tool 10, the power supply voltage (system power supply) for operating the control circuit is continuously supplied from the system power supply circuit 50E to the control circuit 50D. The control circuit 50D acquires temperature information of the driving tool 10 from the sensor 50S (step S101), and determines whether the temperature of the driving tool 10 estimated based on the acquired temperature information is less than a predetermined first threshold. It judges (step S102). If the temperature of the driving tool 10 is less than the first threshold (YES), the control circuit 50D operates the driving tool 10 in the first operation mode (step S103). When the operator pulls the trigger 12E (step S104), the control circuit 50D detects that the trigger 12E has been pulled and supplies a control command (PWM signal) for controlling the motor 20 to the drive circuit 50B. supplies control signals to the switching elements of the inverter circuit 50A, the output voltage of the battery B is applied to the three-phase windings forming the stator of the motor 20, and current flows through the windings of each phase. The rotor of the motor 20 starts rotating according to the rotating magnetic field generated by the current, and the driving tool 10 transitions from the standby state to the operating state. When the motor 20 starts rotating, the torque roller provided on the second gear 22B comes into contact with the gear engagement portion 32A1 of the plunger 32 which has been waiting at the standby position between the top dead center and the bottom dead center, and the plunger 32 is pushed up in the separating direction DR2. Since the plunger 32 is connected to the moving member 38 by the wire 40, the moving member 38 moves in the driving direction DR1 while compressing the coil spring 36 in conjunction with the movement of the plunger 32 in the separating direction DR2. When plunger 32 reaches top dead center, engagement between plunger 32 and gear 22 is released. Therefore, the coil spring 36 that has been in a compressed state expands at once. The moving member 38 moves together with the other end of the coil spring 36 in the separating direction DR2 corresponding to the extension direction of the coil spring 36 . Since the moving member 38 is connected to the plunger 32 by the wire 40, the plunger 32 and the driver 34 move in the ejection direction DR1 in conjunction with the movement of the moving member 38 in the separating direction DR2.

When the plunger 32 reaches near the bottom dead center (or just before reaching), the driver 34 moving in the driving direction DR1 together with the plunger 32 drives the fastener F supplied to the nose portion 12D in the driving direction DR1 (step S105). ). The fastener F is driven out from the injection port 12A and driven into the object.

When the plunger 32 reaches the bottom dead center, the first gear 22A that rotates in synchronization with the rotor of the motor 20 is configured to engage with the gear engaging portion 32A1 of the plunger 32 . Therefore, the plunger 32 starts moving from the bottom dead center toward the top dead center. As the plunger 32 moves toward the top dead center, the coil spring 36 is compressed.

At a predetermined timing, the control circuit 50D starts deceleration control for decelerating the rotation of the motor 20, for example, brake control as an example of deceleration control. Specifically, the control circuit 50D generates a PWM signal whose duty ratio is smaller than that during normal rotation, and outputs it to the drive circuit 50B. The rotation speed of the rotor of the motor 20 is greatly reduced by the deceleration control by the control circuit 50D. Even if the rotational speed decreases, the motor 20 is still rotating, so the plunger 32 continues to slowly move toward the top dead center. Alternatively, as brake control, a short brake that turns off the upper arm of the inverter circuit and turns on the lower arm, or a chopper brake that turns off the upper arm and turns on/off the lower arm by PWM control or the like may be adopted. good.

When the control circuit 50D completes brake control, the rotor of the motor 20 stops rotating, and the plunger 32 stops at the stop position (standby position), so the driving tool 10 transitions from the operating state to the waiting state ( step S106). Thereafter, as long as the temperature of the driving tool 10 is less than the predetermined first threshold value, the fasteners F can be continuously driven into the object by repeating steps S101 to S105.

By performing continuous operation in the first operation mode as indicated by the solid line L1 in FIG. 11, the temperature of the driving tool 10 increases with time.

The timing of supplying the power supply voltage for drive circuit operation from the drive power supply circuit 50C to the drive circuit 50B may be after the main power switch of the driving tool 10 is turned on, or after step S103. It is determined whether or not the power supply voltage for drive circuit operation is supplied, and if it is determined that it is not supplied (for example, when step S103 is executed for the first time after turning on the main power switch of the driving tool 10, (There is a possibility that the drive circuit 50B is not supplied with the power supply voltage for drive circuit operation.).

When the temperature of the driving tool 10 is equal to or higher than the first threshold in step S102 (NO), the control circuit 50D determines whether the temperature of the driving tool 10 is greater than the first threshold and less than a predetermined second threshold ( step S107). If the temperature of the driving tool 10 is less than the second threshold (YES), the control circuit 50D operates the driving tool 10 in the second operation mode (step S108). The driving tool 10 has a notification means for notifying the operator that the temperature of the driving tool 10 has reached a high temperature and that the supply of power supply voltage to the drive circuit 50B in the standby state is stopped or reduced. ing. When the temperature of the driving tool 10 is equal to or higher than the first threshold, the control circuit 50D causes the notification means to perform notification. The notification means may be any means that can be perceived by the operator, and may be, for example, visual notification means such as an LED light, or auditory notification means such as a buzzer. Since the operator can recognize that the driving tool 10 has reached a high temperature by means of the notification means, it is possible to adjust the subsequent work schedule based on the fact that if the work is continued as it is, the operation will eventually stop. be possible.

When the operator pulls the trigger 12E (step S109), the control circuit 50D detects that the trigger 12E has been pulled. A control signal for turning ON is supplied to the ON/OFF circuit 50C1. As a result, the drive power supply circuit 50C starts to supply the power supply voltage for drive circuit operation to the drive circuit 50B (step S110). After that, the control circuit 50D supplies a control command (PWM signal) for controlling the motor 20 to the drive circuit 50B. Thereafter, the operation of the driving tool 10 and the operation for stopping the rotation of the motor 20 by brake control until the fastener F is driven in the driving direction DR1 and driven (step S111) are the same as those described above. A detailed explanation is omitted.

The control circuit 50D shifts the driving tool 10 from the operating state to the standby state based on the elapse of the time required for stopping the rotation of the motor 20 from the start of the brake control for stopping the rotation of the motor 20. It detects that it did (step S112). Next, the control circuit 50D stops supplying the control signal for turning ON the switching element of the ON/OFF circuit 50C1 in order to turn OFF the switching element. As a result, the supply of power supply voltage from the system power supply circuit 50E to the control circuit 50D continues, while the supply of power supply voltage from the drive power supply circuit 50C to the drive circuit 50B stops (step S113). Thereafter, steps S101, S102, and steps S107 to S113 are repeated as long as the temperature of the driving tool 10 is equal to or higher than the first threshold and lower than the second threshold.

For example, assuming that the number of fasteners being driven per minute is 50 and the average drive unit operating time for driving one fastener in the first operation mode is 100 ms, the number of operations per minute is The state time (hereinafter sometimes referred to as "activation time") is 5 seconds, and the standby state time (hereinafter sometimes referred to as "waiting time") is 55 seconds. That is, even when the fasteners F are continuously driven using the driving tool 10, there is a limit to the timing at which the operator can continuously drive the fasteners F into different locations. Wait time is longer.

In the second operation mode, the supply of the power supply voltage to the drive circuit 50B is stopped during at least part of the standby state (for example, 50% or more of the standby state). In comparison, it is possible to suppress heat generation accompanying the supply of the power supply voltage to the drive circuit 50B.

On the other hand, compared to the first operation mode, the second operation mode requires steps such as supplying the power supply voltage to the drive circuit 50B and the time required for current stabilization. than the time required from operating the trigger 12E to hitting (sometimes referred to as response time. For example, 90 ms to 100 ms). The time required (eg, 95 ms to 105 ms) is increased by, eg, 5 ms to 15 ms. In particular, when the DC voltage supplied from the battery B drops, the time required from the operator's operation of the trigger 12E to the firing of the trigger 12E becomes longer. Therefore, the driving tool 10 is configured such that the first operating mode is performed when the driving tool 10 is relatively cold, and the second operating mode is performed when the driving tool 10 is relatively hot. It is By setting the time difference between the first operation mode and the second operation mode to 10 milliseconds or less, the operation by the operator is not greatly hindered. However, the driving tool 10 may be configured so that the operator can selectively execute the first operation mode even at high temperatures, and the operator can selectively execute the second operation mode even at low temperatures. The driving tool 10 may be configured to be able to execute

A dashed line L2 in FIG. 11 indicates the temperature change of the driving tool 10 when the first operation mode is continued even after the temperature of the driving tool 10 exceeds the first threshold value, and a solid line L3 indicates the second operation mode. It shows the temperature change of the driving tool 10 when switching to . As shown in the figure, while the motor 20 and the like are stopped in the standby state of the driving tool 10, it is possible to suppress the heat generation of the drive circuit 50B by stopping the power supply to the drive circuit 50B. . As a result, it has become clear that the temperature rise of the driving tool 10 can be relatively suppressed. As shown in the figure, the time from the first threshold to the second threshold when switching to the second operation mode at the first threshold is the same as the time from the first threshold to the second threshold when the first operation mode is continued. It was at least 1.5 times longer than the time to reach the threshold. In other words, the time from the first threshold to the second threshold when switching to the second operation mode is at least 1.5 times the time from the first threshold to the second threshold when the first operation mode is continued. The driving tool 10 is configured to set the first threshold value to be five times or more. As a result, it is possible to increase the number of times the fastener F can be continuously driven until reaching a temperature at which operation must be stopped in order to prevent component failure of the driving tool 10, thereby reducing the frequency of work interruptions.

The second threshold is preferably set based on the temperature at which the driving tool 10 should stop operating to prevent component failure. For example, when the driving tool 10 is operated continuously, if the CPU of the control circuit 50D among the components of the driving tool 10 reaches its rated temperature (for example, the maximum junction temperature) earliest, the sensor 50S is set to the temperature of the CPU. The driving tool 10 may be configured to be installed nearby and compare the temperature of the CPU estimated based on the information acquired from the sensor 50S with the second threshold value set as the rated temperature of the CPU.

In step S107, when the temperature of the driving tool 10 is equal to or higher than the second threshold (NO), the control circuit 50D stops the operation of the driving tool 10 (step S114).

As described above, it is possible to provide a driving tool capable of suppressing heat generation. It should be noted that the present invention is not applicable only to driving tools. In an electric power tool that has a motor and an inverter circuit for operating the motor and that periodically repeats work, the electric power tool repeats an operating state in which the motor rotates and a standby state in which the motor does not rotate. It can be applied to power tools configured to reduce (including stop) the power supply voltage to a drive circuit for supplying control signals.

For example, when an electric power tool including a driving tool performs clear erasing work (fastener driving work) at least 30 times per minute, the electric power tool (driving tool) according to the present invention performs at least 29 times per minute. In the standby state, each may be configured to include a time during which a reduced power supply voltage is supplied (including no power supply voltage is supplied) to the drive circuit. Also, each waiting time may be less than one second. The power tool (driving tool) is designed so that the time during which the reduced power supply voltage is supplied to the drive circuit per unit time (for example, per minute) is greater than the time during which the drive circuit is supplied with the unreduced power supply voltage. is preferably configured to

Further, the driving tool 10 may be provided with an operation panel through which the operator can input information, for example. The driving tool 10 may be configured so that the operator can set, for example, the first threshold using an operation panel.

[Modification]
In the above embodiment, the sensor 50S acquires information indicating the temperature of the driving tool 10 as information indicating the drive state of the driving tool 10 . However, the information indicating the driving state of the driving tool 10 is not limited to the temperature information of the driving tool 10 .

As this modified example, the sensor 50S acquires information indicating the operation time of the drive unit provided in the power tool. The operating time of the drive unit is information that correlates with the temperature of the power tool. If the power tool is a driving tool, the drive is a motor or plunger. Since the plunger stops when the motor stops, the operating times of the two are substantially the same. Further, as the number of times the fastener F is driven increases, the operation time of the motor or plunger increases and the temperature also rises. is.

As a means for acquiring the operation time of the drive unit, for example, the time for which the control circuit 50D supplies the control command to rotate the motor 20 may be acquired. Further, the operation time of the driving unit may be configured such that, for example, counting starts after the operator turns on the main power switch, and the count becomes zero when the main power switch is turned off.

For example, if the average value of the operation time of the driving unit for driving one fastener is 100 msec, and for example, when switching from the first operation mode to the second operation mode when approximately 1000 fasteners are continuously driven, The operating time of the drive from the start of driving to the driving of 1000 fasteners is 1000.times.100 milliseconds, which is approximately 100 seconds. Therefore, 100 seconds can be set as the first threshold.

Note that the sensor 50S may be configured to be able to acquire information that varies according to the operating time of the driving unit as the information indicating the operating time of the driving unit. For example, the time from turning on the main power switch may be information indicating the operation time of the driving unit, or the standby time of the driving unit may be acquired by the sensor 50S.

Further, the driving information of the electric power tool may include information indicating the number of operations per unit time of the driving unit provided in the electric power tool. As described above, in the power tool, the operating state in which the motor rotates and the standby state in which the motor does not rotate are repeated. As the number of times the fastener F is driven increases, the operating time of the motor or plunger increases and the temperature also rises. .

Here, by acquiring the number of times of operation per unit time (for example, per minute) as drive information, it is possible to enhance the correlation with the temperature. Since the number of operations (the number of times fasteners are driven in the case of a driving tool) is information that is easy for the operator to grasp, the first threshold value can be set by the operator using an input means such as an operation panel. ), it is possible to switch between the first operation mode and the second operation mode according to the operator's work contents. Current information during motor driving may be used as drive information. For example, an integrated current value may be used instead of the operating time.

Also, the present invention can be modified in various ways without departing from the gist thereof. For example, a third operating mode different from the first operating mode and the second operating mode may be configured to be executable. At this time, the third operation mode may be executed after the first operation mode is executed, and then the second operation mode may be executed. Alternatively, the third operation mode may be configured to be executable after the second operation mode is executed. Alternatively, the power supply voltage of the system power supply circuit 50E may be supplied to the drive circuit 50B during standby. Also, two or more temperature sensors are arranged in the package of the motor, the printed wiring board on which the inverter circuit is mounted, and the CPU, and the temperature obtained from any of the temperature sensors is set in anticipation of that. It may be configured to switch to the second operation mode when a first threshold value is reached. In addition, the present invention can be modified within the scope of ordinary creativity of those skilled in the art. For example, it is possible to modify the present invention as follows.

[Modification]
The power tool according to the first embodiment suppresses heat generation in the drive circuit 50B by cutting off the voltage supply to the drive circuit 50B in the standby state when the trigger is not pulled and the trigger is OFF. .

This modification discloses an invention relating to an electric power tool that reduces or cuts off the voltage supply to a portion of the control circuit 50D for controlling the motor 20 in the standby state.
The power tool may be the driving tool 10 or the like, but is not limited to this.

When such an electric power tool is in a standby state, the voltage supply to a part of the control circuit 50D for controlling the motor 20 is reduced or cut off, and the voltage supply to the drive circuit 50B is reduced as described in the first embodiment. may be reduced or cut off. By adopting such a configuration, it becomes possible to realize the embodiment according to this modified example with a simplified configuration.

However, when such an electric power tool is in a standby state, the voltage supply to a part of the control circuit 50D for controlling the motor 20 is reduced or cut off, while the voltage supply to the drive circuit 50B is reduced or cut off. The power tool may be configured to prevent
Note that when the voltage supply to a portion of the control circuit 50D for controlling the motor 20 is reduced or cut off in the standby state, the voltage supply to the other portion of the control circuit 50D is continued. Therefore, voltage supply to other parts is not reduced or cut off. With such a configuration, it is possible to detect that the electric power tool has returned from the standby state to the operating state using another portion of the control circuit 50D.

By adopting the configuration as described above, it is possible to reduce the amount of heat generated by the control circuit 50D, so that it is possible to reduce the amount of heat generated by the power tool.
This modification can be suitably applied to, for example, an electric power tool for which a decrease in response is not a serious problem, or an electric power tool that is activated from a sleep mode by a method other than a trigger operation.

10. driving tool 12 . housing 12E. Trigger 20. motor 22 . gear 24 . PCB board 32 . plunger 34 . driver 40 . wire 42 . pulley 44 . cylinder 50 . Control unit 50A. Inverter circuit 50B. Drive circuit 50C. Drive power supply circuit 50C1. ON/OFF circuit 50D. Control circuit 50E. System power supply circuit 50S. sensor

Claims (10)

a motor;
a switching element for supplying current to the motor;
a drive circuit for supplying a control signal to the switching element;
A power tool comprising
An electric power tool, wherein a voltage supplied to the drive circuit is reduced or cut off based on driving information of the electric power tool. The power tool according to claim 1, wherein the driving information of the power tool includes information indicating the temperature of the power tool. 2. The power tool according to claim 1, wherein the drive information of the power tool includes information indicating an operating time of a driving unit provided in the power tool. 2. The power tool according to claim 1, wherein the drive information of the power tool includes information indicating the number of operations per unit time of a drive unit provided in the power tool. The power tool according to claim 1, wherein the drive information of the power tool includes information indicating the temperature of the motor. 6. The apparatus according to any one of claims 1 to 5, wherein a power supply voltage supplied to said drive circuit is reduced or cut off based on drive information of said power tool when said power tool is in a standby state. The power tool according to any one of the items. 7. The power tool according to claim 6, wherein a threshold value of drive information of the power tool for reducing or cutting off the power supply voltage can be set. The power tool according to any one of claims 1 to 7, further comprising notification means for notifying that the voltage supplied to the drive circuit has been reduced or cut off. The power tool according to any one of claims 1 to 8, wherein the power tool is configured to stop driving when the temperature of the power tool reaches a predetermined value. a motor;
a control circuit for controlling the motor;
A power tool comprising
The control circuit is
driving information of the power tool satisfies a preset condition;
and when the power tool is in a standby state,
The control circuit partially limits execution of its own control processing,
A power tool characterized by:

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