power tools

Abstract

To provide a power tool that allows the motor to be stopped quickly after the work is completed. [Solution] The power tool 100 comprises a motor 1, a holding unit 21, a transmission mechanism 3, a detection unit 4, a determination unit 51, and a control unit 52. The motor 1 rotates when voltage is applied from the battery pack B1. The holding unit 21 holds the tip tool X1. The transmission mechanism 3 transmits the rotation of the motor 1 to the tip tool X1. The detection unit 4 detects the amount of voltage drop over a predetermined period. The determination unit 51 determines whether the amount of voltage drop is greater than a threshold. The control unit 52 stops the motor 1 if the determination unit 51 determines that the amount of voltage drop is greater than a threshold.

Description

Technical Field

[0001] The present disclosure generally relates to power tools. More particularly, the present disclosure relates to power tools having a motor.

Background Art

[0002] Patent Document 1 discloses a power tool including a motor, connection means connectable to a battery pack, voltage detection means, and control means. The voltage detection means detects the voltage value of the battery pack connected to the connection means. The control means restricts the operation of the motor more when the change in the voltage value is large than when it is small based on the change in the voltage value of the secondary battery after operating the motor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a power tool that performs work using the output of a motor, it is required to quickly stop driving the motor after the work is completed.

[0005] An object of the present disclosure is to provide a power tool capable of quickly stopping driving the motor after the work is completed.

Means for Solving the Problems

[0006] An electric tool according to one aspect of the present disclosure comprises a motor, a holding unit, a transmission mechanism, a detection unit, a determination unit, and a control unit. The motor rotates when voltage is applied from a battery pack. The holding unit holds the tool tip. The transmission mechanism transmits the rotation of the motor to the tool tip. The detection unit detects the amount of voltage drop over a predetermined period. The determination unit determines whether the amount of voltage drop is greater than a threshold. The control unit stops the motor if the determination unit determines that the amount of voltage drop is greater than a threshold. [Effects of the Invention]

[0007] According to this disclosure, there is an advantage in that the motor can be quickly stopped after the work is completed. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a block diagram showing the schematic configuration of the power tool according to this embodiment. [Figure 2] Figure 2 is a graph showing the time change in the voltage applied from the battery pack and the time change in the current flowing from the battery pack to the motor in the same power tool. [Figure 3] Figure 3 is a different graph from Figure 2, showing the time change in the voltage applied from the battery pack and the time change in the current flowing from the battery pack to the motor in the same power tool. [Figure 4] Figure 4 is a side view of the main parts of the attachment to the power tool shown above, before the crimping operation is performed. [Figure 5] Figure 5 is a side view of the main parts of the attachment for the power tool shown above after the crimping process has been completed. [Figure 6] Figure 6 is a graph showing the time change in the voltage applied from the battery pack and the time change in the current flowing from the battery pack to the motor in the comparative example power tool. [Figure 7]Figure 7 is a graph showing the time change in the voltage applied to the battery pack and the time change in the current flowing from the battery pack to the motor in the comparative example power tool, when the applied voltage value to the battery pack is less than a predetermined voltage value or the temperature of the battery pack is less than a predetermined temperature. [Figure 8] Figure 8 is a flowchart showing a method for setting the rotational speed of the motor's rotating shaft in the same power tool. [Figure 9] Figure 9 is a flowchart showing a control method for controlling the motor drive in the same power tool. [Modes for carrying out the invention]

[0009] The embodiments and modifications described below are merely examples of the present disclosure. This disclosure is not limited to these embodiments and modifications, and various modifications are possible depending on the design, etc., as long as they do not depart from the technical idea of ​​the present disclosure. The figures described in the embodiments and modifications below are schematic diagrams, and the ratios of the size and thickness of each component in the figures do not necessarily reflect the actual dimensional ratios.

[0010] (Embodiment) (1) Overview The following describes the outline of the power tool 100 according to this embodiment with reference to Figures 1 to 3.

[0011] As shown in Figure 1, the power tool 100 according to this embodiment comprises a motor 1, a holding unit 21, a transmission mechanism 3, a detection unit 4, a determination unit 51, and a motor control unit 52. The motor control unit 52 corresponds to the control unit of this disclosure. The power tool 100 of this embodiment operates when the voltage of the battery pack B1 is applied and is used for work (such as crimping) that is performed using the output of the motor 1.

[0012] The motor 1 rotates when a voltage is applied from the battery pack B1. The holding part 21 holds the tip tool X1 that performs work. The transmission mechanism 3 transmits the rotation of the motor 1 to the tip tool X1. The detection part 4 detects the voltage drop amount ΔV (see FIGS. 2 and 3) applied from the battery pack B1 during a predetermined period ΔT (see FIGS. 2 and 3). The graphs G1 shown in FIGS. 2 and 3 show the time change of the voltage value applied from the battery pack B1, that is, the time change of the battery voltage value of the battery pack B1. That is, the "voltage drop amount ΔV" in the present disclosure is a value indicating how much the voltage value (graph G1) applied from the battery pack B1 has dropped during the predetermined period ΔT.

[0013] The determination part 51 determines whether or not the voltage drop amount ΔV detected by the detection part 4 is greater than a threshold value. When the determination part 51 determines that the voltage drop amount ΔV is greater than the threshold value, the motor control part 52 stops the drive of the motor 1.

[0014] As shown in FIGS. 2 and 3, after the time T1 when the work is completed, due to factors such as an increase in the load applied to the tip tool X1, the value of the current flowing from the battery pack B1 to the motor 1 (graph G2) increases step by step, and the value of the voltage applied from the battery pack B1 (graph G1) decreases step by step, which has been empirically found. For this reason, in the power tool 100 of the present embodiment, when the determination part 51 determines that the voltage drop amount ΔV is greater than the threshold value, the motor control part 52 stops the drive of the motor 1, thereby reducing the difference between the time T1 when the work is completed and the time T2 when the motor 1 stops. That is, the power tool 100 of the present embodiment has the advantage that the drive of the motor 1 can be quickly stopped after the work is completed.

[0015] (2) Detailed configuration (2-1) Power tool Hereinafter, the detailed configuration of the power tool 100 of the present embodiment will be described with reference to FIGS. 1 to 7.

[0016] As shown in FIG. 1, the power tool 100 of this embodiment includes a motor 1, an output shaft 2, a transmission mechanism 3, a detection unit 4, a control unit 5, a reduction mechanism 91, a notification unit 92, and an operation unit 93.

[0017] The power tool 100 of this embodiment is used for a crimping operation that uses the output of the motor 1 in a state where an attachment A1, which is a tip tool X1, is attached. That is, the output of the motor 1 transmitted to the attachment A1, which is the tip tool X1, is used for the crimping operation. The "crimping operation" referred to in the present disclosure is, for example, an operation of crimping a work target W1 (FIGS. 4 and 5), such as a crimp terminal or a sleeve, to an electric wire.

[0018] (Motor) The motor 1 performs a rotational operation (that is, rotates). More specifically, the motor 1 is driven by applying a voltage from the battery pack B1 and performs a rotational operation.

[0019] The motor 1 is, for example, a brushless motor. In particular, the motor 1 of this embodiment is a synchronous motor, and more specifically, a permanent magnet synchronous motor (PMSM). The motor 1 includes a rotor having a rotating shaft 11 (see FIG. 1) and a permanent magnet, and a stator having armature windings for three phases (U phase, V phase, W phase).

[0020] The rotational speed and torque of the rotating shaft 11 of the motor 1 change according to the control by the motor control unit 52. The motor control unit 52 controls the rotational speed and torque of the rotating shaft 11 of the motor 1 by controlling the motor current flowing through the motor 1 when a voltage is applied from the battery pack B1. That is, the motor 1 is controlled by the motor control unit 52 so as to have the rotational speed of the rotating shaft 11 of the motor 1 set by a setting unit 55 described later.

[0021] (Output Shaft) The output shaft 2 is mechanically connected to the rotating shaft 11 of the motor 1 via a reduction mechanism 91 and a transmission mechanism 3. The reduction mechanism 91 converts the rotational speed and torque of the rotating shaft 11 of the motor 1 into the rotational speed and torque required for the operation (in this embodiment, the crimping operation). The transmission mechanism 3 transmits the rotational speed and torque of the rotating shaft 11 of the motor 1, converted by the reduction mechanism 91, to the output shaft 2. That is, the torque of the rotating shaft 11 of the motor 1 is transmitted to the output shaft 2 via the reduction mechanism 91 and the transmission mechanism 3. As a result, the output shaft 2 rotates due to the output of the motor 1 output via the reduction mechanism 91 and the transmission mechanism 3. The output shaft 2 is a so-called spindle.

[0022] The output shaft 2 is provided with a holding portion 21. The holding portion 21 holds the tip tool X1. In this embodiment, the holding portion 21 holds the attachment A1, which is the tip tool X1. In other words, the holding portion 21 in this embodiment is configured so that the attachment A1, which is the tip tool X1, can be detachably attached (mounted). In short, the holding portion 21 in this embodiment is a mounting portion to which the attachment A1 can be detachably attached.

[0023] The transmission mechanism 3 of this embodiment transmits the rotation of the motor 1's rotating shaft 11 to the output shaft 2 on which the holding part 21 is provided. That is, the transmission mechanism 3 of this embodiment transmits the rotation of the motor 1's rotating shaft 11 to the tip tool X1 when the attachment A1, which is the tip tool X1, is attached to the holding part 21.

[0024] (Detection unit) The detection unit 4 detects the voltage drop ΔV applied from the battery pack B1 over a predetermined period ΔT. More specifically, the detection unit 4 measures the voltage value applied from the battery pack B1. After the predetermined period ΔT has elapsed, the detection unit 4 detects the difference between the voltage value measured at the start of the predetermined period ΔT and the voltage value measured at the end of the predetermined period ΔT as the voltage drop ΔV. In this embodiment, the detection unit 4 is, as an example, a voltage measuring instrument that measures the voltage value applied from the battery pack B1.

[0025] The detection unit 4 detects the voltage drop ΔV in each of a plurality of predetermined periods ΔT (see Figure 3). In Figure 3, three predetermined periods ΔT1, ΔT2, and ΔT3 are illustrated as an example, but in reality, the detection unit 4 detects the voltage drop ΔV in each of the plurality of predetermined periods ΔT that constitute the period from the start of the crimping operation until the motor 1 is stopped. That is, the detection unit 4 continuously detects the voltage drop ΔV in the predetermined period ΔT for the entire period from the start of the crimping operation until the motor 1 is stopped.

[0026] (Control Unit) As shown in Figure 1, the control unit 5 includes a determination unit 51, a motor control unit 52, a type acquisition unit 53, a temperature acquisition unit 54, and a setting unit 55.

[0027] The determination unit 51 determines whether the voltage drop ΔV (see Figures 2 and 3) detected by the detection unit 4 is greater than a threshold value. The threshold value is a preset value. For example, the threshold value is preset based on an empirically estimated value of the amount by which the voltage applied from the battery pack B1 decreases in stages after the time T1 (see Figures 2 and 3) when the crimping work is completed.

[0028] In this embodiment, the determination unit 51 determines whether the voltage drop ΔV is greater than a threshold when the mask release condition is met and a predetermined time has elapsed since the determination unit 51 last determined whether the voltage drop ΔV is greater than a threshold. The mask release condition in this embodiment is that at least one of the following conditions is met: a preset mask time has elapsed since the start of the crimping operation, and the value of the current flowing from the battery pack B1 to the motor 1 is greater than or equal to a preset mask release value.

[0029] In this embodiment, the determination unit 51 determines whether the voltage drop ΔV (see Figure 3) in each of the multiple predetermined periods ΔT detected by the detection unit 4 is greater than the threshold, provided that the mask release condition is met and a predetermined time has elapsed since the determination unit 51 last determined whether the voltage drop ΔV is greater than the threshold. For example, the determination unit 51 in this embodiment determines that the voltage drop amounts ΔV1 and ΔV2 (see Figure 3) in predetermined periods ΔT1 and ΔT2, respectively, are less than or equal to the threshold. On the other hand, the determination unit 51 in this embodiment determines that the voltage drop amount ΔV3 (see Figure 3) in predetermined period ΔT3 is greater than the threshold.

[0030] The motor control unit 52 controls the drive (rotational movement) of the motor 1. More specifically, it controls the rotational speed and torque of the motor 1's rotating shaft 11 by controlling the motor current that flows to the motor 1 when voltage is applied from the battery pack B1. The motor control unit 52 controls the motor current so that the rotational speed of the motor 1's rotating shaft 11 is set by the setting unit 55.

[0031] The motor control unit 52 starts driving the motor 1 (i.e., controls the motor 1 to start rotating) when the operation unit 93 receives an operation to start the crimping work and the setting unit 55 sets the rotation speed of the motor 1. More specifically, when the operation unit 93 receives an operation to start the crimping work and the setting unit 55 sets the rotation speed of the motor 1, the motor control unit 52 applies voltage from the battery pack B1 to the motor 1 and controls the motor to flow motor current to the motor 1.

[0032] The motor control unit 52 stops the motor 1 from running (i.e., controls the motor 1 to stop rotating) when the determination unit 51 determines that the voltage drop ΔV is greater than a threshold. More specifically, when the determination unit 51 determines that the voltage drop ΔV is greater than a threshold, the motor control unit 52 controls the motor 1 so that no voltage is applied from the battery pack B1 to the motor 1 and no motor current flows to the motor 1. The motor control unit 52 also stops the motor 1 from rotating when the operation unit 93 receives an operation to end the crimping work.

[0033] The type acquisition unit 53 acquires type information, which is information about the type of battery pack B1 attached to the power tool 100. More specifically, the type information, which is information about the type of battery pack B1 attached to the power tool 100, is stored in the storage unit B13 (see Figure 1), which will be described later, of the battery pack B1, and the type acquisition unit 53 acquires the type information from the storage unit B13. For example, when the battery pack B1 is attached to the power tool 100, the type acquisition unit 53 acquires the type information from the storage unit B13 of the attached battery pack B1.

[0034] In this embodiment, the type information acquired by the type acquisition unit 53 includes the applied voltage value, which is the voltage value that the battery pack B1 attached to the power tool 100 can apply to the motor 1. The "applied voltage value" as used in this disclosure is, for example, the upper limit of the voltage that the battery pack B1 can apply to the motor 1 at room temperature when fully charged and not degraded. As an example, the type information is information indicating whether the applied voltage value of the battery pack B1 attached to the power tool 100 is 14.4V or 18.0V. The type acquisition unit 53 may also acquire the type information by measuring the voltage applied from the battery pack B1 attached to the power tool 100 to the motor 1.

[0035] In other words, the type acquisition unit 53 acquires type information regarding the applied voltage value of the battery pack B1 attached to the power tool 100. For example, the type acquisition unit 53 acquires whether the applied voltage value of the battery pack B1 attached to the power tool 100 is 14.4V or 18.0V.

[0036] The temperature acquisition unit 54 acquires temperature information regarding the temperature of the battery pack B1 attached to the power tool 100. More specifically, the temperature measurement unit B12 (see Figure 1), described later, of the battery pack B1 measures the temperature of the energy storage unit B11, and the temperature acquisition unit 54 acquires the temperature of the energy storage unit B11 measured by the temperature measurement unit B12 as temperature information. The temperature information regarding the temperature of the battery pack B1 may be the temperature of the battery pack B1 itself, or it may be signal information obtained by converting the temperature of the battery pack B1 into a voltage value.

[0037] The setting unit 55 sets the rotation speed of the motor shaft 11 based on the type information acquired by the type acquisition unit 53 and the temperature information acquired by the temperature acquisition unit 54. In other words, the setting unit 55 sets the rotation speed of the motor shaft 11 based on the applied voltage value of the battery pack B1 acquired by the type acquisition unit 53 and the temperature of the battery pack B1 acquired by the temperature acquisition unit 54.

[0038] The setting unit 55 sets the rotation speed of the motor shaft 11 to a first rotation speed when the applied voltage value of the battery pack B1 is equal to or greater than a predetermined voltage value and the temperature of the battery pack B1 is equal to or greater than a predetermined temperature. On the other hand, the setting unit 55 sets the rotation speed of the motor shaft 11 to a second rotation speed, which is lower than the first rotation speed, when the applied voltage value of the battery pack B1 is less than a predetermined voltage value or the temperature of the battery pack B1 is lower than a predetermined temperature. For example, the first rotation speed is 16460 rpm and the second rotation speed is 6580 rpm. For example, the predetermined voltage value is 18.0V. For example, the predetermined temperature is 10℃.

[0039] The control unit 5 preferably includes a computer system. In the computer system, some or all of the functions of the control unit 5 are realized by a processor such as a CPU (Central Processing Unit) or MPU (Micro Processing Unit) reading and executing a program stored in memory. The computer system mainly includes a processor that operates according to the program as its hardware configuration. The type of processor is not limited as long as it can realize its functions by executing a program. The processor consists of one or more electronic circuits including a semiconductor integrated circuit (IC) or an LSI (Large Scale Integration). Here, we refer to them as ICs and LSIs, but the name changes depending on the degree of integration, and they may also be called system LSIs, VLSIs (Very Large Scale Integrations), or ULSIs (Ultra Large Scale Integrations). Field-programmable gate arrays (FPGAs) that are programmed after the manufacture of the LSI, or reconfigurable logic devices that allow for the reconfiguration of junction relationships inside the LSI or the setup of circuit compartments inside the LSI, can also be used for the same purpose. Multiple electronic circuits may be integrated on a single chip or provided on multiple chips. Multiple chips may be integrated into a single device, or they may be provided in multiple devices.

[0040] (Notification Department) The notification unit 92 notifies the crimping operator of how the setting unit 55 has set the rotation speed of the motor shaft 11. In this embodiment, the notification unit 92 notifies the crimping operator that the setting unit 55 has set the rotation speed of the motor shaft 11 to the second rotation speed.

[0041] The notification unit 92 in this embodiment is a light-emitting unit that has a light-emitting element (such as an LED element) and emits light (lights up). The notification unit 92 in this embodiment notifies the crimping worker by emitting light when the setting unit 55 sets the rotation speed of the rotating shaft 11 of the motor 1 to the second rotation speed.

[0042] (Operation unit) The control unit 93 receives commands to control the rotation of the motor shaft 11 of the motor 1. In other words, the control unit 93 receives commands to start or stop the crimping operation performed using the output of the motor 1. The motor 1 can be switched on or off by pulling the control unit 93.

[0043] (2-2) Attachments The tip tool X1 of this embodiment is an attachment A1 that is detachably attached to the holding part 21 of the power tool 100. As shown in Figures 1, 4, and 5, the attachment A1, which is the tip tool X1, comprises an engaging part A11, a drive mechanism A12, a female die A13, and a male die A14. With the workpiece W1 (Figures 4 and 5), which is a crimp terminal or sleeve, and an electric wire (not shown) inserted between the female die A13 and the male die A14, the male die A14 is driven toward the female die A13, causing the female die A13 and the male die A14 to crimp the workpiece W1 to the electric wire.

[0044] The engaging portion A11 engages with the holding portion 21 of the power tool 100. In this embodiment, the engaging portion A11 engages with the holding portion 21 provided on the output shaft 2 of the power tool 100.

[0045] The drive mechanism A12 uses the output (rotation) of the motor 1's rotating shaft 11 to drive the male die A14 toward the female die A13. The drive mechanism A12 receives the rotation of the output shaft 2, i.e., the rotation of the motor 1's rotating shaft 11, when the engaging portion A11 is engaged with the holding portion 21. The drive mechanism A12 drives the male die A14 from a state where the workpiece W1 and the electric wire are inserted between the female die A13 and the male die A14 (see Figure 4) to a state where the female die A13 and the male die A14 have crimped the workpiece W1 to the electric wire (see Figure 5). In other words, in this embodiment, the output (rotation) of the motor 1's rotating shaft 11, which is the tip tool X1 of the attachment A1, is used for the crimping operation.

[0046] It has been empirically observed that, after the time when the male die A14 is driven toward the female die A13 and the workpiece W1 is crimped to the wire (i.e., after the time when the crimping operation is completed), the value of the current flowing from the battery pack B1 to the motor 1 (graph G2) increases in stages and the value of the voltage applied from the battery pack B1 (graph G1) decreases in stages, as shown in Figures 2 and 3, due to factors such as an increase in the load applied to the male die A14.

[0047] (2-3) Battery pack The battery pack B1 is a rechargeable power supply unit that can be detachably attached to the power tool 100. In this embodiment, the battery pack B1 is not a component of the power tool 100. However, the power tool 100 may include the battery pack B1 as a component.

[0048] As shown in Figure 1, the battery pack B1 comprises a power storage unit B11, a temperature measuring unit B12, and a memory unit B13.

[0049] The energy storage unit B11 is a rechargeable secondary battery. The temperature measuring unit B12 measures the temperature of the energy storage unit B11. The temperature measuring unit B12 outputs the measurement result to the temperature acquisition unit 54 of the power tool 100. The temperature measuring unit B12 is, for example, a temperature sensor.

[0050] The storage unit B13 stores type information, which is information about the type of battery pack B1 attached to the power tool 100. In this embodiment, the type information stored in the storage unit B13 includes the applied voltage value, which is the voltage value that the battery pack B1 can apply to the motor 1 of the power tool 100. The storage unit B13 is, for example, a storage device such as a magnetic core memory or a semiconductor memory. Alternatively, the storage unit B13 may be an auxiliary storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive).

[0051] (3) Comparison Graph Ge1 in Figure 6 shows the time variation of the voltage applied from the battery pack in the comparative example power tool. On the other hand, graph Ge2 in Figure 6 shows the time variation of the current flowing from the battery pack to the motor in the comparative example power tool.

[0052] As shown in Figure 6, in the comparative example power tool, it has been empirically observed that, after the time Te1 when the crimping work is completed, the value of the current flowing from the battery pack to the motor (graph Ge2) increases in stages due to factors such as an increase in the load applied to the tip tool, and the value of the voltage applied from battery pack B1 (graph Ge1) decreases in stages. For this reason, in the comparative example power tool, the motor control unit stops the motor drive when the value of the current flowing from the battery pack to the motor exceeds a preset stop current value Ath, or when the value of the voltage applied from the battery pack falls below a preset stop voltage value Vth. Note that Figure 6 illustrates the case where the value of the voltage applied from the battery pack falls below the stop voltage value Vth before the value of the current flowing from the battery pack to the motor exceeds the stop current value Ath. As a result, in the comparative example power tool, the difference between the time Te1 when the crimping work is completed and the time Te2 when the motor drive is stopped can become large.

[0053] Graph G1 shown in Figures 2 and 3 shows the time change in the voltage applied from the battery pack B1 in the power tool 100 of this embodiment. On the other hand, graph G2 shown in Figures 2 and 3 shows the time change in the current flowing from the battery pack B1 to the motor 1 in the power tool 100 of this embodiment.

[0054] In the power tool 100 of this embodiment, the motor control unit 52 stops the motor 1 when the determination unit 51 determines that the voltage drop ΔV is greater than a threshold. Therefore, the time T2 during which the motor control unit 52 stops the motor 1 is closer to the time T1 when the work is finished than the time during which the current flowing from the battery pack B1 to the motor 1 is expected to exceed the stop current value Ath, or the time during which the voltage applied from the battery pack B1 is expected to fall below the stop voltage value Vth. In other words, the power tool 100 of this embodiment has the advantage that the difference between the time T1 when the work is finished and the time T2 when the motor 1 is stopped can be made smaller than that of the power tool of the comparative example.

[0055] Furthermore, Graph Ge3 in Figure 7 shows the time change in the voltage applied from the battery pack in the comparative example power tool when the applied voltage value of the battery pack is less than a predetermined voltage value, or when the temperature of the battery pack is below a predetermined temperature. On the other hand, Graph Ge4 in Figure 7 shows the time change in the current flowing from the battery pack to the motor in the comparative example power tool when the applied voltage value of the battery pack is less than a predetermined voltage value, or when the temperature of the battery pack is below a predetermined temperature.

[0056] As shown in Figure 7, in the comparative example power tool, when the applied voltage of the battery pack is less than a predetermined voltage, or when the temperature of the battery pack is less than a predetermined temperature, it is conceivable that at time Te3, before the crimping work is completed, the value of the current flowing from the battery pack to the motor will exceed a preset stop current value Ath, or the value of the voltage applied from the battery pack will fall below a preset stop voltage value Vth. In the comparative example power tool, in the above case, the motor drive is stopped at time Te3, before the work is completed. Note that Figure 7 illustrates the case where the value of the voltage applied from the battery pack falls below the stop voltage value Vth at time Te3, before the work is completed.

[0057] On the other hand, in the power tool 100 of this embodiment, the setting unit 55 sets the rotation speed of the motor 1's rotating shaft 11 based on the applied voltage value of the battery pack B1 acquired by the type acquisition unit 53 and the temperature of the battery pack B1 acquired by the temperature acquisition unit 54. Therefore, in the power tool 100 of this embodiment, when the applied voltage value of the battery pack B1 is smaller than a predetermined voltage value, or when the temperature of the battery pack B1 is smaller than a predetermined temperature, it is possible to suppress the value of the current flowing from the battery pack B1 to the motor 1 from exceeding the stop current value Ath, or the value of the voltage applied from the battery pack B1 from falling below the stop voltage value Vth, before the crimping work is completed. As a result, the power tool 100 of this embodiment has the advantage of being able to suppress the stopping of the motor 1's drive before the crimping work is completed, regardless of the type and temperature of the battery pack B1.

[0058] (4) Operation (4-1) How to set the rotation speed First, the method for setting the rotational speed of the rotating shaft 11 of the motor 1 in the power tool 100 will be explained with reference to Figure 8.

[0059] As shown in Figure 8, the rotation speed setting method includes a type acquisition step ST11, a first determination step ST12, a temperature acquisition step ST13, a second determination step ST14, a third determination step ST15, a setting step ST16, a notification step ST17, and a drive step ST18.

[0060] In the type acquisition step ST11, the type acquisition unit 53 acquires type information, which is information relating to the type of battery pack B1 attached to the power tool 100. More specifically, in the type acquisition step ST11, the type acquisition unit 53 acquires type information stored in the storage unit B13 of the battery pack B1 attached to the power tool 100. In the type acquisition step ST11 of this embodiment, the type acquisition unit 53 acquires type information relating to the applied voltage value of the battery pack B1 attached to the power tool 100. As an example, when the battery pack B1 is attached to the power tool 100, the type acquisition unit 53 performs the type acquisition step ST11.

[0061] In the first determination step ST12, the motor control unit 52 determines whether or not the operation unit 93 has received an operation to start the crimping work. If the motor control unit 52 determines that the operation unit 93 has not received an operation to start the crimping work (ST12: No), the motor control unit 52 continues the first determination step ST12. On the other hand, if the motor control unit 52 determines that the operation unit 93 has received an operation to start the crimping work (ST12: Yes), the temperature acquisition unit 54 performs a temperature acquisition step ST13 to acquire temperature information, which is information regarding the temperature of the battery pack B1 attached to the power tool 100. More specifically, in the temperature acquisition step ST13, the temperature acquisition unit 54 acquires the temperature of the energy storage unit B11 measured by the temperature measurement unit B12 as temperature information.

[0062] In the second determination step ST14, the setting unit 55 determines whether the applied voltage value of the battery pack B1 is equal to or greater than a predetermined voltage value. In the third determination step ST15, the setting unit 55 determines whether the temperature of the battery pack B1 is equal to or greater than a predetermined temperature. In the rotation speed setting method of this embodiment, the setting unit 55 performs the third determination step ST15 after determining in the second determination step ST14 that the applied voltage value of the battery pack B1 is equal to or greater than a predetermined voltage value (ST14: Yes).

[0063] In setting step ST16, the setting unit 55 sets the rotation speed of the motor shaft 11. More specifically, in setting step ST16, if it is determined that the applied voltage value of the battery pack B1 is equal to or greater than a predetermined voltage value (ST14: Yes), and that the temperature of the battery pack B1 is equal to or greater than a predetermined temperature (ST15: Yes), the setting unit 55 performs a first setting step ST161 to set the rotation speed of the motor shaft 11 to a first rotation speed. On the other hand, in setting step ST16, if it is determined that the applied voltage value of the battery pack B1 is less than a predetermined voltage value (ST14: No), or if it is determined that the temperature of the battery pack B1 is less than a predetermined temperature (ST15: No), the setting unit 55 performs a second setting step ST162 to set the rotation speed of the motor shaft 11 to a second rotation speed.

[0064] In notification step ST17, the notification unit 92 notifies the crimping operator of how the setting unit 55 has set the rotation speed of the motor shaft 11. In the rotation speed setting method of this embodiment, the notification unit 92 performs notification step ST17 to notify the operator that the setting unit 55 has set the rotation speed of the motor shaft 11 to the second rotation speed after the setting unit 55 has performed the second setting step ST162. More specifically, in notification step ST17, the notification unit 92 notifies the crimping operator that the setting unit 55 has set the rotation speed of the motor shaft 11 to the second rotation speed by emitting light.

[0065] In the drive step ST18, the motor control unit 52 drives the motor 1 to the rotational speed set by the setting unit 55 in the setting step ST16 (i.e., it controls the motor 1 so that the motor 1 starts to drive).

[0066] Note that the flowchart in Figure 8 is merely one example of a method for setting the rotation speed in the power tool 100 of this embodiment, and the order of the processes may be changed as appropriate, or any of the processes may be omitted as appropriate. For example, the order of the second determination step ST14 and the third determination step ST15 may be changed as appropriate.

[0067] (4-2) Control Method Next, a control method for controlling the drive (rotational movement) of the motor 1 in the power tool 100 will be explained with reference to Figure 9.

[0068] The control method, as shown in Figure 9, includes a voltage measurement step ST21, a first determination step ST22, a detection step ST23, a second determination step ST24, a third determination step ST25, a fourth determination step ST26, and a control step ST27.

[0069] In the voltage measurement step ST21, the detection unit 4 measures the voltage applied from the battery pack B1. In the first determination step ST22, the detection unit 4 determines whether a predetermined period ΔT has elapsed since the detection unit 4 measured the voltage applied from the battery pack B1 in the voltage measurement step ST21. If the detection unit 4 determines that the predetermined period ΔT has not elapsed (ST22: No), the detection unit 4 continues the first determination step ST22. If the detection unit 4 determines that the predetermined period ΔT has elapsed (ST22: No), the detection unit 4 performs the detection step ST23. In the detection step ST23, the detection unit 4 detects the voltage drop ΔV from the battery pack B1 over the predetermined period ΔT by measuring the voltage applied from the battery pack B1 again.

[0070] In the second determination step ST24, the determination unit 51 determines whether or not the mask release condition is met. The mask release condition in this embodiment is that at least one of the following conditions is met: a preset mask time has elapsed since the start of the crimping operation, and the value of the current flowing from the battery pack B1 to the motor 1 is equal to or greater than a preset mask release value. That is, in the second determination step ST24 of this embodiment, the determination unit 51 determines whether or not at least one of the following conditions is met: a preset mask time has elapsed since the start of the crimping operation, and the value of the current flowing from the battery pack B1 to the motor 1 is equal to or greater than a preset mask release value.

[0071] In the third determination step ST25, the determination unit 51 determines whether a predetermined time has elapsed since the last determination of whether the voltage drop ΔV is greater than the threshold. In the control method of this embodiment, the determination unit 51 performs the third determination step ST25 after determining in the second determination step ST24 that the mask release condition is met (ST24: Yes).

[0072] If the determination unit 51 determines that the mask release condition is not met (ST24: No), or if the determination unit 51 determines that a predetermined amount of time has not elapsed since the last determination of whether the voltage drop ΔV is greater than the threshold (ST25: No), the detection unit 4 performs the voltage measurement step ST21. On the other hand, if the determination unit 51 determines that the mask release condition is met (ST24: Yes), and if the determination unit 51 determines that a predetermined amount of time has elapsed since the last determination of whether the voltage drop ΔV is greater than the threshold (ST25: Yes), the determination unit 51 performs the fourth determination step ST26. In the fourth determination step ST26, the determination unit 51 determines whether the voltage drop ΔV detected in the current detection step ST23 is greater than the threshold.

[0073] If the determination unit 51 determines that the voltage drop ΔV is not greater than the threshold, that is, that the voltage drop ΔV is less than or equal to the threshold (ST26: No), the detection unit 4 performs the voltage measurement step ST21. On the other hand, if the determination unit 51 determines that the voltage drop ΔV is greater than the threshold (ST26: No), the motor control unit 52 performs the control step ST27 to stop the motor 1 from running (that is, to control the motor 1 so that it stops rotating). More specifically, in the control step ST27, the motor control unit 52 controls the motor 1 so that no voltage is applied from the battery pack B1 and no motor current flows to the motor 1.

[0074] Note that the flowchart in Figure 9 is merely one example of the control method for the power tool 100 of this embodiment, and the order of the processes may be changed as appropriate, or any of the processes may be omitted as appropriate. For example, the order of the second determination step ST24 and the third determination step ST25 may be changed as appropriate.

[0075] (5) Advantages The power tool 100 of this embodiment comprises a motor 1, a holding unit 21, a transmission mechanism 3, a detection unit 4, a determination unit 51, and a motor control unit 52. The motor 1 rotates when voltage is applied from the battery pack B1. The holding unit 21 holds the tip tool X1 to be used for work. The transmission mechanism 3 transmits the rotation of the motor 1 to the tip tool X1. The detection unit 4 detects the voltage drop ΔV (see Figures 2 and 3) applied from the battery pack B1 over a predetermined period ΔT. The determination unit 51 determines whether the voltage drop ΔV detected by the detection unit 4 is greater than a threshold. The motor control unit 52 stops the motor 1 from running if the determination unit 51 determines that the voltage drop ΔV is greater than the threshold.

[0076] As a result, the power tool 100 of this embodiment can reduce the difference between the time T1 when the work is completed and the time T2 when the motor 1 stops running. In other words, the power tool 100 of this embodiment has the advantage of being able to quickly stop the motor 1 after the work is completed.

[0077] The power tool 100 of this embodiment further comprises a type acquisition unit 53 and a setting unit 55. The type acquisition unit 53 acquires type information, which is information relating to the type of battery pack B1 attached to the power tool 100. The setting unit 55 sets the rotation speed of the rotation shaft 11 of the motor 1 based on the type information acquired by the type acquisition unit 53.

[0078] In the comparative example power tool, depending on the type of battery pack attached to the power tool, the voltage applied from the battery pack may fall below the stop voltage value Vth before the work is completed. In the comparative example power tool, in the above case, the motor is stopped before the work is completed. On the other hand, in the power tool 100 of this embodiment, the setting unit 55 sets the rotation speed of the motor 1's rotating shaft 11 based on the type of battery pack B1 acquired by the type acquisition unit 53, thereby suppressing the voltage applied from the battery pack B1 from falling below the stop voltage value Vth. As a result, the power tool 100 of this embodiment has the advantage of being able to suppress the stopping of the motor 1 before the work is completed, regardless of the type of battery pack B1 attached to the power tool 100.

[0079] In the power tool 100 of this embodiment, the type information acquired by the type acquisition unit 53 includes the applied voltage value, which is the voltage value that the battery pack B1 attached to the power tool 100 can apply to the motor 1.

[0080] In the comparative example power tool, depending on the voltage value that the battery pack can apply to the motor, it is possible that the voltage applied from the battery pack may fall below the stop voltage value Vth before the work is completed. In the comparative example power tool, in the above case, the motor is stopped before the work is completed. On the other hand, in the power tool 100 of this embodiment, the setting unit 55 sets the rotation speed of the motor shaft 11 of the motor 1 based on the voltage value that the battery pack B1 can apply to the motor 1, thereby suppressing the voltage value applied from the battery pack B1 from falling below the stop voltage value Vth. As a result, the power tool 100 of this embodiment has the advantage of being able to suppress the stopping of the motor 1 before the work is completed, regardless of the voltage value that the battery pack B1 can apply to the motor 1.

[0081] In the power tool 100 of this embodiment, the setting unit 55 sets the rotation speed of the motor shaft 11 to a first rotation speed when the applied voltage value of the battery pack B1 is equal to or greater than a predetermined voltage value. On the other hand, the setting unit 55 sets the rotation speed of the motor shaft 11 to a second rotation speed, which is lower than the first rotation speed, when the applied voltage value of the battery pack B1 is less than a predetermined voltage value.

[0082] This has the advantage of more effectively preventing the motor 1 from stopping before the work is finished, regardless of the voltage value that the battery pack B1 can apply to the motor 1.

[0083] The power tool 100 of this embodiment further comprises a temperature acquisition unit 54 and a setting unit 55. The temperature acquisition unit 54 acquires temperature information, which is information relating to the temperature of the battery pack B1 attached to the power tool 100. The setting unit 55 sets the rotation speed of the rotation shaft 11 of the motor 1 based on the temperature information acquired by the temperature acquisition unit 54.

[0084] In the comparative example power tool, depending on the temperature of the battery pack attached to the power tool, the voltage applied from the battery pack may fall below the stop voltage value Vth before the work is completed. In the comparative example power tool, in the above case, the motor is stopped before the work is completed. On the other hand, in the power tool 100 of this embodiment, the setting unit 55 sets the rotation speed of the motor 1's rotating shaft 11 based on the temperature of the battery pack B1 acquired by the temperature acquisition unit 54, thereby suppressing the voltage applied from the battery pack B1 from falling below the stop voltage value Vth. As a result, the power tool 100 of this embodiment has the advantage of being able to suppress the stopping of the motor 1 before the work is completed, regardless of the temperature of the battery pack B1 attached to the power tool 100.

[0085] In the power tool 100 of this embodiment, the setting unit 55 sets the rotation speed of the motor shaft 11 to a first rotation speed when the temperature of the battery pack B1 is above a predetermined temperature. On the other hand, the setting unit 55 sets the rotation speed of the motor shaft 11 to a second rotation speed which is lower than the first rotation speed when the temperature of the battery pack B1 is below the predetermined temperature.

[0086] This has the advantage of more effectively preventing the motor 1 from stopping before the work is finished, regardless of the temperature of the battery pack B1 attached to the power tool 100.

[0087] In the power tool 100 of this embodiment, the output (rotation) of the motor 1 transmitted to the attachment A1, which is the tip tool X1, is used for crimping work.

[0088] As a result, the power tool 100 of this embodiment has the advantage that the motor 1 can be quickly stopped after the crimping work is completed.

[0089] (6) Variant The embodiments described above are merely one of many embodiments of this disclosure. These embodiments can be modified in various ways depending on the design, etc., as long as they achieve the objectives of this disclosure. The following modifications may be implemented in appropriate combinations.

[0090] In the above embodiment, the holding portion 21 is configured to allow attachment A1, which is the tip tool X1, to be attached to or removed. However, the holding portion 21 may also hold the tip tool X1 by being integrated with the tip tool X1. In other words, the tip tool X1 does not have to be configured to be attached to or removed from the holding portion 21 of the power tool 100. In short, the tip tool X1 does not have to be attachment A1.

[0091] In the above-described embodiment, the control unit 5 has both a type acquisition unit 53 and a temperature acquisition unit 54. However, the control unit 5 may have at least one of the type acquisition unit 53 and the temperature acquisition unit 54.

[0092] If the control unit 5 has only a type acquisition unit 53, the setting unit 55 sets the rotation speed of the motor 1's rotating shaft 11 based only on the type information acquired by the type acquisition unit 53. Specifically, the setting unit 55 sets the rotation speed of the motor 1's rotating shaft 11 to a first rotation speed when the applied voltage value of the battery pack B1 is equal to or greater than a predetermined voltage value. On the other hand, the setting unit 55 sets the rotation speed of the motor 1's rotating shaft 11 to a second rotation speed, which is smaller than the first rotation speed, when the applied voltage value of the battery pack B1 is less than a predetermined voltage value.

[0093] Furthermore, if the control unit 5 has only a temperature acquisition unit 54, the setting unit 55 sets the rotation speed of the motor 1's rotating shaft 11 based solely on the temperature information acquired by the temperature acquisition unit 54. Specifically, the setting unit 55 sets the rotation speed of the motor 1's rotating shaft 11 to a first rotation speed when the temperature of the battery pack B1 is above a predetermined temperature. On the other hand, the setting unit 55 sets the rotation speed of the motor 1's rotating shaft 11 to a second rotation speed, which is lower than the first rotation speed, when the temperature of the battery pack B1 is below the predetermined temperature.

[0094] (summary) The power tool (100) of the first embodiment includes a motor (1), a holding part (21), a transmission mechanism (3), a detection unit (4), a determination unit (51), and a control unit (52). The motor (1) rotates when voltage is applied from a battery pack (B1). The holding part (21) holds the tip tool (X1). The transmission mechanism (3) transmits the rotation of the motor (1) to the tip tool (X1). The detection unit (4) detects the amount of voltage drop (ΔV) over a predetermined period (ΔT). The determination unit (51) determines whether the amount of voltage drop (ΔV) is greater than a threshold. The control unit (52) stops the motor (1) if the determination unit (51) determines that the amount of voltage drop (ΔV) is greater than a threshold.

[0095] This embodiment has the advantage that the motor (1) can be quickly stopped after the work is completed.

[0096] The power tool (100) in the second embodiment further comprises a type acquisition unit (53) and a setting unit (55) in the first embodiment. The type acquisition unit (53) acquires type information, which is information relating to the type of battery pack (B1). The setting unit (55) sets the rotation speed of the motor (1) based on the type information.

[0097] This embodiment has the advantage that, regardless of the type of battery pack (B1) attached to the power tool (100), it is possible to prevent the motor (1) from stopping before the work is completed.

[0098] In the third embodiment of the power tool (100), in the second embodiment, the type information includes an applied voltage value which is the voltage value that the battery pack (B1) can apply to the motor (1).

[0099] This embodiment has the advantage that it can prevent the motor (1) from stopping before the work is completed, regardless of the voltage value that the battery pack (B1) can apply to the motor (1).

[0100] In the fourth embodiment of the power tool (100), in the third embodiment, the setting unit (55) sets the rotation speed to a first rotation speed when the applied voltage value is equal to or greater than a predetermined voltage value. The setting unit (55) sets the rotation speed to a second rotation speed lower than the first rotation speed when the applied voltage value is less than the predetermined voltage value.

[0101] This embodiment has the advantage that it can better prevent the motor (1) from stopping before the work is completed, regardless of the voltage value that the battery pack (B1) can apply to the motor (1).

[0102] The power tool (100) of the fifth embodiment further comprises a temperature acquisition unit (54) and a setting unit (55) in any of the first to fourth embodiments. The temperature acquisition unit (54) acquires temperature information, which is information relating to the temperature of the battery pack (B1). The setting unit (55) sets the rotation speed of the motor (1) based on the temperature information.

[0103] This embodiment has the advantage that it is possible to prevent the motor (1) from stopping before the work is completed, regardless of the temperature of the battery pack (B1) attached to the power tool (100).

[0104] In the sixth embodiment of the power tool (100), in the fifth embodiment, the setting unit (55) sets the rotation speed to a first rotation speed when the temperature is above a predetermined temperature. The setting unit (55) sets the rotation speed to a second rotation speed lower than the first rotation speed when the temperature is below the predetermined temperature.

[0105] This embodiment has the advantage that it is possible to further suppress the stopping of the motor (1) before the work is completed, regardless of the temperature of the battery pack (B1) attached to the power tool (100).

[0106] In the seventh embodiment of the power tool (100), in any of the first to sixth embodiments, the output of the motor (1) transmitted to the tip tool (X1) is used for crimping work.

[0107] This embodiment has the advantage that the motor (1) can be quickly stopped after the crimping operation is completed. [Explanation of Symbols]

[0108] 100 Power tools 1 motor 3. Transmission mechanism 4. Detection Unit 52 Control Unit (Motor Control Unit) 21 Holding part 51 Judgment section 53 Types Acquisition Unit 54 Temperature acquisition section 55 Setting section B1 Battery Pack X1 Tip tool ΔT Predetermined period ΔV: Voltage drop

Claims

1. A motor that rotates when voltage is applied from a battery pack, A holder for the tip tool, A transmission mechanism that transmits the rotation of the motor to the tip tool, A detection unit for detecting the amount of voltage drop during a predetermined period, A determination unit that determines whether the voltage drop is greater than a threshold, The system includes a control unit that stops the motor when the determination unit determines that the voltage drop is greater than the threshold, Power tools.

2. A type acquisition unit that acquires type information, which is information regarding the type of the battery pack, The system further includes a setting unit that sets the rotation speed of the motor based on the type information. The power tool according to claim 1.

3. The type information includes an applied voltage value which is the voltage value that the battery pack can apply to the motor. The power tool according to claim 2.

4. The aforementioned setting unit is, When the applied voltage value is equal to or greater than a predetermined voltage value, the rotation speed is set to the first rotation speed. If the applied voltage value is smaller than the predetermined voltage value, the rotation speed is set to a second rotation speed that is lower than the first rotation speed. The power tool according to claim 3.

5. A temperature acquisition unit that acquires temperature information, which is information relating to the temperature of the battery pack, The system further includes a setting unit that sets the rotation speed of the motor based on the temperature information. The power tool according to claim 1.

6. The aforementioned setting unit is, If the temperature is above a predetermined temperature, the rotation speed is set to the first rotation speed. If the temperature is lower than the predetermined temperature, the rotation speed is set to a second rotation speed that is lower than the first rotation speed. The power tool according to claim 5.

7. The output of the motor transmitted to the tip tool is used for the crimping operation. The power tool according to any one of claims 1 to 6.

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