Work machine

Abstract

To improve convenience of a work machine.SOLUTION: A nail gun 1A includes: a motor 44; a plunger 21 and a driver blade which strike a fastener; a coil spring 23 which biases the plunger 21 downward; a gear group 25 which receives a driving force of the motor 44 to operate and serves a rotation part including a first gear, a second gear, and a third gear; a battery pack 5 which may supply electric power to the motor 44; and a controller 6 which controls driving of the motor 44. The controller 6 performs warm-up control for supplying limited electric power which is limited so as to prevent operation of the gear group 25 from the battery to the motor 44 when a temperature of the battery is low.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a work machine such as a nail driver. [Background technology]

[0002] One example of a work machine is a driving tool that has a piston that can reciprocate within a cylinder, a driver blade that engages with the piston and strikes the fastener, a return mechanism that returns the piston from bottom dead center to top dead center, and an electric motor that drives the return mechanism.

[0003] As an example of such a driving machine, Patent Document 1 discloses a driving machine (nailer) that supplies power to an electric motor and is equipped with a detachable battery. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2018 / 003370 Summary of the Invention [Problem to be solved by the invention]

[0005] It is known that a battery's output decreases as its temperature drops due to factors such as an increase in internal resistance. In an electric driving tool like the one described in Patent Document 1, if the return speed of the piston changes due to a decrease in battery output, the response during operation changes, which changes the user experience. For this reason, a control is generally implemented to prohibit operation at low temperatures.

[0006] Specifically, the battery is disabled even if there is sufficient remaining battery power. Therefore, there is room for improvement in the convenience of the driving tool.

[0007] An object of the present invention is to provide a work machine with improved convenience. [Means for solving the problem]

[0008] A work machine according to one embodiment comprises a motor, an operating unit that operates upon receiving the driving force of the motor, a battery capable of supplying power to the motor, and a control unit that controls the operation of the motor, and the control unit performs warm-up control to supply limited power from the battery to the motor when the battery is at a low temperature so that the operating unit does not operate.

[0009] A work machine in another embodiment has a motor, an impact unit that strikes a stopper, a biasing unit that biases the impact unit to one side in a first direction, a rotating unit that can engage with the impact unit and receives the driving force of the motor to move the impact unit to the other side in the first direction against the biasing force of the biasing unit, a battery that can supply power to the motor, and a control unit that controls the drive of the motor, and the control unit performs warm-up control that outputs power from the battery so that the rotating unit does not operate when the battery is at a low temperature. [Effects of the Invention]

[0010] According to the present invention, the convenience of the work machine can be improved. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a side view showing the structure of the nail driver. [Figure 2] FIG. 2 is a schematic diagram showing the structure of a striking mechanism provided in the nail driver. [Figure 3] 10A and 10B are explanatory diagrams showing the operation of the impact mechanism. [Figure 4] 10A and 10B are other explanatory views showing the operation of the impact mechanism. [Figure 5] 10A and 10B are other explanatory views showing the operation of the impact mechanism. [Figure 6] FIG. 2 is a block diagram showing a control mechanism of the nail gun. [Figure 7] 10 is a flowchart showing an algorithm for executing warm-up control of the nail gun. [Figure 8]1 is a current-torque curve showing the relationship between battery current and motor torque of a nail gun. [Figure 9] 1 is a voltage-temperature threshold curve showing the relationship between the battery voltage and the temperature threshold of a nail gun. [Figure 10] 1 is a time-battery temperature curve showing the relationship between the warm-up operation time of the nail gun and the battery temperature. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment will be described in detail below with reference to the drawings. In all drawings referred to in describing the embodiment, the same or substantially the same configurations and elements are designated by the same reference numerals. Furthermore, once a configuration or element has been described, the description will not be repeated.

[0013] <Outline of the nail gun> The working machine according to this embodiment is suitable for driving fasteners such as nails and staples into mating materials such as wood and gypsum board. More specifically, the working machine according to this embodiment is a nail driver that drives nails into mating materials. In this embodiment, a nail 8 will be described as an example of a fastener that is driven by a nail driver.

[0014] 1 is a side view showing the structure of a nail driver 1A according to this embodiment. The nail driver 1A has a housing 2, a magazine 3, an ejection unit 4, and the like.

[0015] The housing 2 has a main body 10, a handle 11, a motor housing 12, and a connecting portion 13. One longitudinal end of the handle 11 and the motor housing 12 is connected to the main body 10, and the other longitudinal end of the handle 11 and the motor housing 12 is connected to the connecting portion 13. In other words, the main body 10, the handle 11, the motor housing 12, and the connecting portion 13 are integrated.

[0016] A plurality of nails 8 are loaded into the magazine 3. The plurality of nails 8 loaded into the magazine 3 are supplied one by one to the ejection unit 4. The ejection unit 4 supports the nails 8 sent from the magazine 3 so that they can be ejected.

[0017] When an operator performs a predetermined operation on the operating section including the trigger lever 7 and push lever 9 provided on the handle section 11, the nail 8 supported by the ejection section 4 is struck by a striking mechanism 20 (FIG. 2) described later. As a result, the nail 8 is ejected from the ejection section 4 and driven into the target material.

[0018] <Housing> The main body 10 of the housing 2 has a generally rectangular cylindrical shape overall. Here, the longitudinal direction of the main body 10 shown in Fig. 1 is defined as the "up-down direction," and the longitudinal direction of the handle portion 11 and the motor accommodating portion 12 is defined as the "front-rear direction." Furthermore, the direction perpendicular to the up-down direction and the front-rear direction is defined as the "left-right direction." However, these definitions are merely for the convenience of explanation.

[0019] According to the above definition, the handle portion 11 is located above the motor housing portion 12 and extends rearward from the back surface of the main body portion 10. On the other hand, the motor housing portion 12 is located below the handle portion 11 and extends rearward from the back surface of the main body portion 10. The motor housing portion 12 houses a motor 44. Furthermore, the connecting portion 13 connects the rear end of the handle portion 11 and the rear end of the motor housing portion 12.

[0020] A battery attachment section to which a battery pack 5 can be attached and detached is provided on the back surface of the connecting section 13. The battery pack 5 contains a battery 16 (see FIG. 6 described later) capable of supplying power to the motor 44. A controller 6 serving as a control section is also housed inside the connecting section 13.

[0021] In this embodiment, the downward direction corresponds to the first direction of the present invention, and the upward direction corresponds to the second direction (the direction opposite to the first direction) of the present invention.

[0022] The housing 2 is composed of two housing members made of synthetic resin such as nylon or polycarbonate. More specifically, the two housing members are butted together and fixed to form the housing 2, which has a main body portion 10, a handle portion 11, a motor accommodating portion 12, and a connecting portion 13.

[0023] At least a portion of the surface of the housing 2 is covered with a resin cover. More specifically, at least a portion of the surface of the housing 2 is covered with a resin layer (elastomer layer) formed (laminated) on the housing 2 by two-layer molding (two-color molding).

[0024] <Impact mechanism> 2 is a schematic diagram showing the structure of the striking mechanism 20 provided in the nail driver 1A. The striking mechanism 20 is composed of a plunger 21, a driver blade 22, a coil spring 23, a counterweight 24, a gear group 25, a guide bar 26, etc., which are housed in the main body 10 (FIG. 1).

[0025] The plunger 21 and the driver blade 22 are capable of striking the nail 8 supported by the ejection part 4 (FIG. 1) and correspond to the striking part of the present invention. The coil spring 23 is capable of biasing the plunger 21 and the driver blade 22 downward and corresponds to the biasing part of the present invention.

[0026] Plunger The plunger 21 has three arms (arms 31, 32, and 33) and a pin 34. The arms 31, 32, and 33 protrude rearward, and the pin 34 protrudes forward.

[0027] The pin 34 is inserted into a through hole provided at the upper end of the driver blade 22. As a result, the plunger 21 and the driver blade 22 can move together in the up and down direction.

[0028] Coil spring The coil spring 23 is formed of a spirally wound wire. The lower end of the coil spring 23 abuts against the plunger 21, and the upper end of the coil spring 23 abuts against the counterweight 24.

[0029] Counterweight The counterweight 24 has a rectangular cylindrical shape, and the upper part of the coil spring 23 is inserted into the inside of the counterweight 24. As a result, the upper end of the coil spring 23 abuts against the inner surface of the bottom wall of the counterweight 24 inside the counterweight 24.

[0030] An arm 35 similar to the arm provided on the plunger 21 is provided on the rear side of the counterweight 24.

[0031] The coil spring 23 is disposed between the plunger 21 and the counterweight 24, which are opposed to each other in the vertical direction. Therefore, when the coil spring 23 contracts, the plunger 21 and the counterweight 24 move closer to each other. On the other hand, when the coil spring 23 expands, the plunger 21 and the counterweight 24 move away from each other.

[0032] From another perspective, when the striking part (plunger 21, driver blade 22) moves downward, the counterweight 24 moves upward. On the other hand, when the striking part (plunger 21, driver blade 22) moves upward, the counterweight 24 moves downward.

[0033] That is, the striking portion (plunger 21, driver blade 22) and the counterweight 24 move in opposite directions. The up and down movements of the plunger 21, driver blade 22, and counterweight 24 will be explained later.

[0034] <Gears> The gear group 25 includes a first gear 41, a second gear 42, and a third gear 43. The first gear 41, the second gear 42, and the third gear 43 are each supported so as to be rotatable.

[0035] The gear group 25 receives the driving force output from the motor 44 (FIG. 1) via the gear box 45 (FIG. 1). In other words, the gear group 25 is an operating unit that operates upon receiving the driving force of the motor 44. More specifically, the driving force output from the motor 44 is input to the first gear 41 via a planetary gear reduction mechanism housed in the gear box 45. The first gear 41, the second gear 42, and the third gear 43 are rotating units that can engage with the plunger 21 and receive the driving force of the motor 44 to move the plunger 21 upward against the biasing force of the coil spring 23. In other words, the first gear 41, the second gear 42, and the third gear 43 correspond to both the operating unit and the rotating unit of the present invention. The gear box 45 has a built-in one-way clutch that functions as both a reduction gear and a one-way clutch. The one-way clutch allows the motor 44 to rotate in the forward direction, and restricts the motor 44 from rotating in the reverse direction.

[0036] The first gear 41 meshes with the second gear 42, and the second gear 42 meshes with the third gear 43. In other words, the second gear 42 meshes with both the first gear 41 and the third gear 43. Therefore, when the driving force output from the motor 44 is input to the first gear 41, the first gear 41, the second gear 42, and the third gear 43 each rotate.

[0037] That is, the first gear 41, the second gear 42, and the third gear 43 are rotating parts that rotate by the driving force output from the motor 44. Cam rollers, which will be described later, are provided on the front surfaces of the first gear 41, the second gear 42, and the third gear 43.

[0038] <Guide bar> The guide bar 26 is a thin metal member that extends in the vertical direction. Note that a similar guide bar 26 is disposed behind the guide bar 26 shown in Fig. 2. In other words, the striking mechanism 20 is provided with a pair of guide bars 26 that face each other in the left-right direction.

[0039] The lower end of each guide bar 26 is fixed to the bottom holder 51, and the upper end of each guide bar 26 is fixed to the top holder 52. From another perspective, the bottom holder 51 and the top holder 52 are connected by the pair of guide bars 26.

[0040] The plunger 21 is disposed between the lower end of the coil spring 23 and the bottom holder 51 , and a ring-shaped lower damper 53 is disposed between the plunger 21 and the bottom holder 51 .

[0041] The counterweight 24 is disposed between the upper end of the coil spring 23 and the top holder 52, and a ring-shaped upper damper 54 is disposed between the counterweight 24 and the top holder 52.

[0042] The lower damper 53 and the upper damper 54 are made of an elastic material such as rubber. The lower damper 53 receives the biasing force of the coil spring 23 and receives the plunger 21 moving downward, and prevents damage or deformation of the bottom holder 51 due to a collision of the plunger 21.

[0043] On the other hand, the upper damper 54 receives the counterweight 24 that moves upward due to the biasing force of the coil spring 23, and prevents damage or deformation of the top holder 52 due to a collision of the counterweight 24.

[0044] In the following description, the lower damper 53 may be referred to as the "plunger damper 53" and the upper damper 54 may be referred to as the "weight damper 54."

[0045] A guide shaft 23a that passes through the coil spring 23 is provided between a pair of opposing guide bars 26. The lower part of the guide shaft 23a passes through the plunger 21 and plunger damper 53 and is connected to the bottom holder 51. The upper part of the guide shaft 23a passes through the counterweight 24 and weight damper 54 and is connected to the top holder 52.

[0046] The guide shaft 23a guides the expansion and contraction of the coil spring 23. At the same time, the guide shaft 23a guides the up and down movement of the plunger 21 and the counterweight 24.

[0047] From another perspective, the guide bar 26, the guide shaft 23a, the bottom holder 51, and the top holder 52 form a frame that supports the plunger 21 and the counterweight 24 so that they can move up and down.

[0048] <Operation of the impact mechanism> 3, 4, and 5 are explanatory diagrams showing the operation of the striking mechanism 20. The plunger 21 and the counterweight 24 shown in FIGS. 3, 4, and 5 are located at different positions in the vertical direction.

[0049] More specifically, the plunger 21 and counterweight 24 shown in Figure 3 are in a first position (standby position), the plunger 21 and counterweight 24 shown in Figure 4 are in a second position (top dead center), and the plunger 21 and counterweight 24 shown in Figure 5 are in a third position (bottom dead center).

[0050] It should be noted that each of the first position (standby position), second position (top dead center), and third position (bottom dead center) is a position range having a certain width, and is not limited to a single point.

[0051] As described above, cam rollers are provided on the front surfaces of the first gear 41, second gear 42, and third gear 43. More specifically, cam roller 41a is provided on the front surface of the first gear 41. Cam rollers 42a and 42b are provided on the front surface of the second gear 42. Cam rollers 43a and 43b are provided on the front surface of the third gear 43.

[0052] 3, when the plunger 21 is in the standby position, the cam roller 42a of the second gear 42 engages with the arm 32 of the plunger 21 from below. When the counterweight 24 is in the standby position, the cam roller 43b of the third gear 43 engages with the arm 35 of the counterweight 24 from above.

[0053] Furthermore, the stopper 27, which is rotatably mounted on the guide bar 26, has begun to engage with the counterweight 24, which is located in the standby position. However, the stopper 27 has not yet completely engaged with the counterweight 24. Note that the stopper 27 is not shown in Figure 2.

[0054] 1 can switch the state of the motor 44 based on predetermined conditions and information, and controls the driving of the motor 44. For example, when the plunger 21 and the counterweight 24 are positioned in the standby position and a predetermined operation is performed on the operating unit including the trigger lever 7 and the push lever 9, the controller 6 switches the motor 44 from a stopped state to an operating state. More specifically, the controller 6 supplies power from the battery pack 5 to the motor 44, and switches the motor 44 from a stopped state in which it does not output driving force to an operating state in which it outputs driving force.

[0055] When the motor 44 is switched to an operating state, a driving force is input to the first gear 41 shown in Fig. 3. At this time, the first gear 41 rotates with the plunger 21 engaged with the first gear 41. As a result, the first gear 41 rotates counterclockwise, the second gear 42 rotates clockwise, and the third gear 43 rotates counterclockwise.

[0056] When the second gear 42 rotates clockwise, the plunger 21 is pushed up by the cam roller 42a of the second gear 42, which is engaged with the arm 32 of the plunger 21. As a result, the plunger 21 moves upward against the bias of the coil spring 23. In other words, the plunger 21 moves up while compressing the coil spring 23.

[0057] On the other hand, when the third gear 43 rotates counterclockwise, the cam roller 43b of the third gear 43, which is engaged with the arm 35 of the counterweight 24, pushes down the counterweight 24. As a result, the counterweight 24 moves downward against the bias of the coil spring 23. In other words, the counterweight 24 descends while compressing the coil spring 23. At the same time, the engagement of the stopper 27 with the counterweight 24 is completed.

[0058] Thereafter, the second gear 42 continues to rotate clockwise, and the third gear 43 continues to rotate counterclockwise, causing the cam roller 42b of the second gear 42 to further push up the plunger 21. As a result, the plunger 21 continues to compress the coil spring 23 and rises to the top dead center shown in FIG.

[0059] Meanwhile, the cam roller 43b of the third gear 43 moves away from the arm 35 of the counterweight 24. That is, the engagement between the cam roller 43b and the counterweight 24 is released. However, the engagement of the stopper 27 with the counterweight 24 is completed before the engagement between the cam roller 43b and the counterweight 24 is released.

[0060] 4 before the plunger 21. After reaching the top dead center, the counterweight 24 is held at the top dead center by the stopper 27.

[0061] When plunger 21 rises to the top dead center, cam roller 42b of second gear 42 separates from arm 33 of plunger 21. In other words, engagement between cam roller 42b and plunger 21 is released. Then, plunger 21 receives the restoring force (biasing force) of coil spring 23 and descends to the bottom dead center shown in FIG. 5, and driver blade 22 attached to plunger 21 also descends to the bottom dead center shown in FIG. 5.

[0062] Even if the engagement between the cam roller 42b and the plunger 21 is released, the restriction on the movement of the counterweight 24 by the stopper 27 is not released. In other words, the counterweight 24 does not start rising at the same time that the plunger 21 starts to descend.

[0063] The movement restriction of the stopper 27 on the counterweight 24 is released after the plunger 21 descends to a predetermined position. The counterweight 24, whose movement restriction has been released, rises to the bottom dead center shown in FIG. 5 due to the restoring force (biasing force) of the coil spring 23.

[0064] As described above, the plunger 21 and the counterweight 24 move in opposite directions. The driver blade 22, which moves integrally with the plunger 21, strikes the nail supported by the ejection unit 4 during the movement.

[0065] At this time, the counterweight 24 moves in the opposite direction to the plunger 21 and the driver blade 22, thereby reducing the reaction when the driver blade 22 strikes the nail.

[0066] In this way, one driving operation is completed. If the conditions for continuing the driving operation are not satisfied when the driving operation is completed, the controller 6 shown in Fig. 1 stops the motor 44 without proceeding to the next driving operation.

[0067] For example, when the driving operation is completed and the operation on the trigger lever 7 and the push lever 9 is released, the controller 6 stops the motor 44. More specifically, the controller 6 switches the motor 44 from an operating state to a stopped state.

[0068] However, the controller 6 does not stop the motor 44 immediately after the completion of the driving operation. The controller 6 stops the motor 44 after moving the plunger 21 and the counterweight 24 to the standby position shown in Figure 3 in preparation for the next driving operation.

[0069] Specifically, the controller 6 keeps the motor 44 in an operating state even after the driving operation is completed. As a result, the cam roller 41a of the first gear 41 shown in Fig. 5 re-engages with the plunger 21 and pushes the plunger 21 up. Also, the cam roller 43b of the third gear 43 re-engages with the counterweight 24 and pushes the counterweight 24 down.

[0070] Next, before the cam roller 41a of the first gear 41 disengages from the arm 31 of the plunger 21, the cam roller 42a of the second gear 42 engages with the arm 32 of the plunger 21 to push the plunger 21 up to the standby position.

[0071] Furthermore, before the cam roller 43a of the third gear 43 disengages from the arm 35 of the counterweight 24, the cam roller 43b of the third gear 43 engages with the arm 35 of the counterweight 24, pushing the counterweight 24 down to the standby position. In this way, the plunger 21 is pushed up from the bottom dead center to the top dead center against the biasing force of the coil spring 23.

[0072] <Position detection unit> The nailing machine 1A is provided with a position detection unit that detects the position of the counterweight 24. More specifically, the nailing machine 1A is provided with a top dead center switch 60 as a microswitch that is operated by the counterweight 24.

[0073] 4, when the counterweight 24 is at the top dead center, the protrusion 24a on the counterweight 24 comes into contact with and presses the actuator of the top dead center switch 60. Furthermore, the protrusion 24a continues to come into contact with and press the actuator of the top dead center switch 60 while the counterweight 24 moves from the standby position to the top dead center.

[0074] The top dead center switch 60 outputs a detection signal while the actuator is being pressed by the protrusion 24a of the counterweight 24. The detection signal output from the top dead center switch 60 is input to the controller 6.

[0075] 5, when the counterweight 24 starts to move from the top dead center toward the bottom dead center, the protrusion 24a moves away from the actuator of the top dead center switch 60. Then, the top dead center switch 60 stops outputting a detection signal, and the input of the detection signal to the controller 6 stops.

[0076] <Nailer circuit configuration> 6 is a block diagram showing the control mechanism of the nail gun 1A. A controller 6, which is a control unit, mainly controls the driving of a motor 44. The motor 44 is connected to an inverter circuit 18 including switching elements SW1, SW2, and SW3 via a control signal output circuit 19. The switching element SW1 is used for braking control of the motor 44, the switching element SW2 is used for duty control of the motor 44, and the switching element SW3 is used to form a dual circuit.

[0077] The motor 44 is connected to the battery 16 built into the battery pack 5, and power is supplied from the battery 16 to the motor 44.

[0078] The battery pack 5 has a communication terminal 15, which is electrically connected to the communication terminal 14 of the nail driver 1A. The battery pack 5 has a temperature sensor 17 built therein that detects the temperature of the battery 16.

[0079] A current detection circuit 64 and a voltage detection circuit 65 are connected to the battery 16, and the magnitudes of the output current and output voltage of the battery 16 are input to the controller 6. A resistor R1 is connected to the current detection circuit 64. A power supply voltage supply circuit 69 is also connected to the battery 16 via a power switch circuit 68, and a power supply voltage is applied to the controller 6. A trigger switch operation detection circuit 70 is connected to the power switch circuit 68 via a trigger switch 66, and a push switch operation detection circuit 71 is further connected to the power switch circuit 68 via a push switch 67. As a result, a signal from the trigger switch 66 generated by the operator's operation of the trigger lever 7 is input to the controller 6 via the trigger switch operation detection circuit 70, and a signal from the push switch 67 generated by the operator's operation of the push lever 9 is input to the controller 6 via the push switch operation detection circuit 71.

[0080] Furthermore, the temperature sensor 17 incorporated in the battery pack 5 is connected to a battery temperature detection circuit 72 and a battery type detection circuit 73 via communication terminals 15, 14, and information such as the temperature of the battery 16 and the type of battery 16 is input to the controller 6. Furthermore, a top dead center switch 60 that detects the movement of the plunger 21 is connected to the controller 6 via a top dead center switch operation detection circuit 61, and a signal from the top dead center switch 60 is input to the controller 6. Furthermore, a hoisting gear rotational position sensor 62 that detects the drive of the motor 44 is connected to the controller 6 via a hoisting gear rotational position sensor detection circuit 63, and a signal from the hoisting gear rotational position sensor 62 is input to the controller 6. The hoisting gear rotational position sensor 62 can detect the drive of the motor 44 by, for example, providing a magnet on the hoisting gear and a Hall IC on the housing. Furthermore, an LED 74 is connected to the controller 6, and displays information to notify the operator. For example, the LED 74 lights up during the warm-up operation mode, and blinks if the battery temperature and voltage do not reach the threshold value even after the warm-up operation mode ends.

[0081] Furthermore, a coil (load section) 75 and a switching element SW4 are connected to the motor 44, and the controller 6 controls the battery 16 to supply power to the coil 75 as required. <Motor warm-up control> The nail gun 1A of this embodiment has a mode in which, when the battery 16 is at a low temperature, a small amount of power is supplied to the motor 44 so that the motor 44, the first gear 41, the second gear 42, and the third gear 43 do not rotate. This mode will be referred to as a warm-up operation mode hereinafter. Specifically, when the battery 16 is at a low temperature, the controller 6 performs warm-up control to supply limited power from the battery 16 to the motor 44 so that the first gear 41, the second gear 42, and the third gear 43, which are operating parts (rotating parts), do not operate. In other words, when the battery 16 is at a low temperature, the controller 6 performs control to supply small amount of power (limited power) from the battery 16 to the motor 44 so that the first gear 41, the second gear 42, and the third gear 43 do not operate. This control will also be referred to as warm-up control of the controller 6.

[0082] The warm-up control of the nail gun 1A will be described using the flowchart of Fig. 7. First, in step S1, the "start-up" of the nail gun 1A is executed. Specifically, when the trigger and push lever are operated with the plunger 21 shown in Fig. 3 in the standby position, the trigger switch 66 and push switch 67 shown in Fig. 6 are turned on. A predetermined amount of power is supplied from the battery pack 5 to the motor 44, and the nail gun 1A starts up.

[0083] Next, step S2, "Above or Beyond Battery Temperature / Voltage Threshold," is executed. Here, it is determined whether the temperature of the battery 16 and the output voltage of the battery 16 are above or equal to a threshold. Specifically, it is determined whether the temperature of the battery 16 detected by the temperature sensor 17 shown in FIG. 6 is above or equal to a preset temperature threshold, and whether the output voltage of the battery 16 detected by the voltage detection circuit 65 is above or equal to a preset output voltage threshold. If both the temperature of the battery 16 and the output voltage of the battery 16 are above or equal to a threshold (YES), it is determined that the power required to operate the first gear 41, the second gear 42, and the third gear 43 can be supplied to the motor 44, and the controller 6 supplies the predetermined power to the motor 44.

[0084] As a result, the nail gun 1A starts normal operation ("normal operation" in step S3). Although not shown in FIG. 7, in step S3, the plunger 21 and the counterweight 24 are first positioned at their standby positions, and the controller 6 enters a standby state in which it waits for an operation on the trigger lever 7 and the push lever 9 (signal input from the trigger switch operation detection circuit 70 and the push switch operation detection circuit 71). When signals are input from the trigger switch operation detection circuit 70 and the push switch operation detection circuit 71, the controller 6 supplies a predetermined amount of power to the motor 44, thereby operating the first gear 41, the second gear 42, and the third gear 43 to move the plunger 21 and the counterweight 24 from the first position (standby position) through the second position (top dead center) to the third position (bottom dead center). After detecting that the plunger 21 and the counterweight 24 have returned to the first position (standby position), the controller 6 stops the power supply to the motor 44, thereby performing a single nail driving operation. That is, in step S2, which occurs before and after the start of step S3, the plunger 21 and the counterweight 24 are in the first position (standby position).

[0085] On the other hand, if at least the temperature detected by the temperature sensor 17, among the temperature detected by the temperature sensor 17 and the output voltage of the battery 16, is below the preset threshold (NO), the LED 74 shown in Fig. 6 displays a low temperature error ("Low temperature error LED display" in step S4). As a result, the controller 6 performs warm-up control ("Warm-up operation mode" in step S5).

[0086] As described above, when the operating unit is operated (the trigger and push lever are operated), the controller 6 determines whether the temperature of the battery 16 is low, and if it determines that the battery 16 is low, it performs warm-up control. In this case, the controller 6 determines that the battery 16 is low in temperature when the temperature of the battery 16 detected by the temperature sensor 17 falls below a preset temperature threshold. Alternatively, the controller determines that the battery 16 is low in temperature when the output voltage of the battery 16 falls below a predetermined voltage threshold (a preset output voltage threshold).

[0087] When the controller 6 determines that the battery 16 is at a low temperature, the controller 6 executes the "warm-up operation mode" in step S5. Specifically, the controller 6 performs warm-up control to supply limited power from the battery 16 to the motor 44 so that the first gear 41, the second gear 42, and the third gear 43 do not operate.

[0088] As shown in FIG. 6 , a switching circuit using a switching element SW2 is provided on the power path supplied from the battery 16 to the motor 44. In warm-up control, the controller 6 duty-controls the switching circuit so that the supply current supplied from the battery 16 to the motor 44 reaches a target value, thereby supplying limited power from the battery 16 to the motor 44. That is, when executing warm-up control, the controller 6 duty-controls the switching circuit so that the supply current supplied from the battery 16 to the motor 44 reaches a target value. In other words, in warm-up control, the controller 6 adjusts the duty of the current applied to the motor 44 to control the magnitude of the motor torque. That is, the duty is set so that the current value is equal to or less than the motor torque required to wind (push up) the plunger 21. Because a duty of 100% is a current value that can push up the plunger 21, in warm-up control, a current of approximately 50% duty, for example, is applied to the motor 44.

[0089] The limit power is the power at which the torque output by the motor 44 is smaller than the operation start torque required for the operating parts including the first gear 41, the second gear 42, and the third gear 43 to transition from a stopped state to an operating state. Therefore, when the limit power is supplied to the motor 44, the magnitude of the motor torque to be output is small, and therefore the battery 16 can be warmed without pushing up the plunger 21.

[0090] FIG. 8 shows an example of the relationship between battery current and motor torque for nail gun 1A. The motor torque required to wind (push up) plunger 21 is Tr0 (N·m) at a current value of A0 (A). The motor torque during warm-up operation (warm-up control, limited power) is Tr2 (N·m) at a current value of A2 (A). The motor torque during normal winding (normal pushing up) is Tr1 (N·m) at a current value of A1 (A). The magnitudes of the currents are A1 > A0 > A2, and the magnitudes of the motor torques are Tr1 > Tr0 > Tr2. In other words, during warm-up operation, the motor current is set to A2 so that Tr2 has a motor torque smaller than Tr0. For example, if battery 16 is 18V, A1 is 25A (DUTY 100%), A2 is 12.5A (DUTY 50%), Tr1 is 0.2N·m, and Tr2 is 0.1N·m.

[0091] Note that when the controller 6 determines in step S2 whether the temperature of the battery 16 and the output voltage of the battery 16 are equal to or greater than the threshold, it is not essential to determine the output voltage of the battery 16. FIG. 9 shows an example of the relationship between the battery voltage and the temperature threshold of the nail gun 1A. When the combination of the temperature and the battery voltage is below the temperature threshold (Tth) shown by the solid line (normal operation impossible region U2), the nail gun 1A enters warm-up operation. On the other hand, when the combination of the temperature and the battery voltage is above the temperature threshold (Tth) shown by the solid line (normal operation possible region U1), the nail gun 1A enters normal operation. For example, when the battery 16 is 18V, the battery voltage Vth1 is 17V, and the temperature threshold Tth1 at this time is 5°C. Furthermore, the battery voltage Vth2 is 20.5V (fully charged), and the temperature threshold Tth2 at this time is -10°C. That is, if the battery 16 is 18V and the battery voltage is 17V, warm-up operation will start when the battery temperature drops below 5°C, and if the battery voltage is 20.5V (fully charged), warm-up operation will start when the battery temperature drops below -10°C. Note that if the battery voltage is below Vth1, the motor 44 will not be driven (low voltage error) regardless of the battery temperature.

[0092] Furthermore, the controller 6 can change the criteria for determining whether the battery 16 is at a low temperature depending on the type of the battery 16. There are multiple types of batteries 16, for example, depending on the type of cell, the number of cells, etc. Therefore, the criteria for determining whether the battery 16 is at a low temperature may be changed depending on the type of the battery 16.

[0093] Furthermore, in the warm-up control, the controller 6 supplies limited power to the motor 44 for a specified time (e.g., 20 seconds), and if the battery 16 is still cold after the specified time has elapsed, stops the warm-up control. That is, the "battery temperature / voltage threshold or higher within threshold time" step S6 is executed. Here, the controller 6 supplies limited power to the motor 44 for a specified time, and if the battery 16 is still cold after the specified time has elapsed (NO), the controller 6 executes "low voltage error display" step S7 and stops the warm-up control. Thereafter, the controller 6 executes "power off" step S8. On the other hand, if the battery temperature / voltage becomes equal to or higher than the threshold within the threshold time (YES), the controller 6 executes "battery temperature / voltage threshold or higher" step S2 again.

[0094] FIG. 10 shows the relationship between the warm-up operation time and the battery temperature of the nail gun 1A. When the warm-up operation starts, the battery temperature is T0°C, which is lower than the temperature threshold value Tth. After the warm-up operation starts, the battery temperature gradually increases as time passes, and when the warm-up operation time reaches TD, the battery temperature is T1°C, which is higher than the temperature threshold value Tth. In other words, because the battery temperature exceeds the threshold value (T1>Tth), the warm-up operation (warm-up control) is stopped.

[0095] Furthermore, when the controller 6 determines in step S2 whether the temperature of the battery 16 and the output voltage of the battery 16 are equal to or higher than the thresholds, the plunger 21 and the counterweight 24 are in the first position (standby position), and the plunger 21 and the counterweight 24 do not move until warm-up operation (warm-up control) is performed. Here, when the plunger 21 is in the standby position (first position) in Fig. 3, the force of the coil spring 23 is applied to the plunger 21, so the drive torque of the operating parts including the first gear 41, the second gear 42, and the third gear 43 increases, making it difficult to drive the motor 44. For this reason, the limited power can be increased during warm-up operation (warm-up control).

[0096] Furthermore, when the controller 6 detects that the plunger 21 is located below the standby position, it does not perform warm-up control. That is, when the plunger 21 is located below the standby position (the top dead center switch 60 is in the OFF state), the biasing force that the plunger 21 receives from the coil spring 23 is smaller than the biasing force that the plunger 21 receives at the standby position. This means that the amount of power that can be output from the battery 16 to the motor 44 is reduced, resulting in an error state. In other words, warm-up control is performed only in a range where the drive torque of the operating part is large, and in this case, the controller 6 does not perform warm-up control.

[0097] Furthermore, when controller 6 detects movement of plunger 21 while warm-up control is being executed, it stops the warm-up control. That is, when plunger 21 moves from the standby position shown in FIG. 3 toward the top dead center while warm-up control is being executed, top dead center switch 60 turns ON, and controller 6 detects the movement of plunger 21. As a result, when controller 6 detects movement of plunger 21 while warm-up control is being executed, it stops the warm-up control.

[0098] 1 is provided with a one-way clutch in the gearbox 45 that allows the motor 44 to rotate in the forward direction and restricts it from rotating in the reverse direction. During warm-up control, the controller 6 sets the rotation direction of the motor 44 to the reverse direction restricted by the one-way clutch and supplies a large amount of power from the battery 16 to the motor 44.

[0099] In this case, the motor 44 is prevented from rotating in the reverse direction by the one-way clutch, so even if a large amount of power is supplied to the motor 44, the motor 44 does not rotate and the plunger 21 does not move. Therefore, the battery 16 can be warmed up quickly.

[0100] The nail gun 1A also includes a load unit that does not operate a rotating unit including the first gear 41, the second gear 42, and the third gear 43 even when it consumes power supplied from the battery 16. The load unit is, for example, a coil 75 shown in FIG. 6. The coil 75 is a load separate from the motor 44 and is capable of consuming power supplied from the battery 16. In this case, the controller 6 supplies a large amount of power from the battery 16 to the coil 75 during warm-up control. Since the coil 75 consumes a large amount of power, the power supplied to the motor 44 is not enough to operate the rotating unit and does not move the plunger 21. In other words, even if the power output from the battery 16 is increased, the coil 75 consumes that large amount of power, and therefore the power supplied to the motor 44 is not enough to operate the rotating unit. This allows the battery 16 to be warmed up without moving the plunger 21.

[0101] <Effects> According to the nail driver 1A of the present embodiment, even when the battery 16 is at a low temperature, limited power that does not wind up the plunger 21 is supplied from the battery 16 to the motor 44, so that power can be supplied to the motor 44 without moving the plunger 21. In other words, when the battery 16 is at a low temperature, power is supplied to the motor 44 such that only a motor torque lower than that required to push up the plunger 21 can be output.

[0102] In the standby position, the motor 44 is under load from the coil spring 23, so even if power that can only output a low motor torque as described above is supplied to the motor 44, the plunger 21 cannot compress the coil spring 23, and the motor 44 is locked. In this case, although the motor 44 is locked, power is still being supplied from the battery 16 to the motor 44, so the battery 16 itself warms up. In other words, the battery 16 warms up because it is discharging.

[0103] This allows the remaining battery charge to be greater than the threshold even at low temperatures, preventing the execution of control that would disable the battery 16. As a result, the frequency with which the battery 16 needs to be charged can be reduced, improving the convenience of the nail driver 1A.

[0104] In the nail driver 1A, the load on the motor 44 is the drive torque of the operating and rotating parts, so the load exists to a certain extent. Therefore, in the case of the nail driver 1A, it is easy to define the limit power.

[0105] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, the LED 74 shown in Fig. 6 may be a notification unit that notifies that the warm-up operation mode has been entered, or may be a display unit (display) that displays the temperature of the battery 16 itself.

[0106] In addition, when using the LED 74 as an alarm unit, the controller 6 may notify the operator that warm-up control has been stopped if the battery 16 is still at a low temperature after a specified time has elapsed, or may notify the operator that warm-up control is being performed while warm-up control is being performed.

[0107] In addition, the controller 6 may control the warm-up control to stop if the supply current does not reach a predetermined current threshold during the warm-up control, or the controller 6 may control the warm-up control to stop if it detects that the motor 44 has been driven during the warm-up control.

[0108] The device may have a pressure accumulator chamber as a biasing unit having compressed gas therein, and a piston as a striking unit that is operated by the pressure of the compressed gas in the pressure accumulator chamber. In this case, a temperature sensor may be provided to detect the temperature of the pressure accumulator chamber, and the temperature of battery 16 may be estimated from the detected value of the temperature sensor. Alternatively, a temperature sensor may be provided to detect the temperatures of other components such as the operating unit or motor 44, and the temperature of battery 16 may be estimated from the detected value. [Explanation of symbols]

[0109] 1A... Nail gun (working machine), 2... Housing, 3... Magazine, 4... Injection unit, 5... Battery pack, 6... Controller (control unit), 7... Trigger lever, 8... Nail (fastener), 9... Push lever, 10... Main body, 11... Handle, 12... Motor housing, 13... Connection unit, 14... Communication terminal, 15... Communication terminal, 16... Battery, 17... Temperature sensor, 18... Inverter circuit, 19... Control signal output circuit, 2 0...impact mechanism, 21...plunger, 22...driver blade, 23...coil spring, 23a...guide shaft, 24...counterweight, 24a...projection, 25...gear group (operating part), 26...guide bar, 27...stopper, 31, 32, 33...arm, 34...pin, 35...arm, 41...first gear, 41a...cam roller, 42...second gear, 42a, 42b...cam roller, 43...third gear, 43a, 43b... Cam roller, 44... Motor, 45... Gear box, 51... Bottom holder, 52... Top holder, 53... Lower damper, 54... Upper damper, 60... Top dead center switch, 61... Top dead center switch operation detection circuit, 62... Winding gear rotation position sensor, 63... Winding gear rotation position sensor detection circuit, 64... Current detection circuit, 65... Voltage detection circuit, 66... ​​Trigger switch, 67... Push switch, 68... Power switch circuit, 69... Power supply voltage supply circuit, 70... Trigger switch operation detection circuit, 71... Push switch operation detection circuit, 72... Battery temperature detection circuit, 73... Battery type detection circuit, 74... LED, 75... Coil (load section), R1... Resistor, SW1, SW2, SW3, SW4... Switching elements, U1... Normal operation possible area, U2... Normal operation impossible area, Tth... Temperature threshold, TD... Warm-up operation time

Claims

1. A motor; an operating unit that operates by receiving a driving force from the motor; a battery capable of supplying power to the motor; a control unit that controls the driving of the motor, The control unit performs warm-up control to supply limited power from the battery to the motor when the battery is at a low temperature so that the operating unit does not operate.

2. a striking portion that strikes the fastener; a biasing portion that biases the striking portion to one side in a first direction; a rotating portion that is engageable with the impact portion and receives a driving force of the motor to move the impact portion to the other side in the first direction against the biasing force of the biasing portion, The work machine according to claim 1 , wherein the operating part is the rotating part.

3. an operating unit operated by an operator, The hitting part is When the operating unit is operated at the first position, the rotating unit rotates while being engaged with the rotating unit, thereby moving the operating unit to the second position toward the other side in the first direction against the biasing force of the biasing unit, When the engagement with the rotating portion is released at the second position, the biasing force of the biasing portion moves the rotating portion to one side in the first direction to a third position, 3. The work machine according to claim 2, wherein the rotating portion rotates while re-engaged with the rotating portion at the third position, thereby moving to the other side of the first direction against the biasing force of the biasing portion to the first position and stopping there.

4. The work machine according to claim 3 , wherein the control unit does not perform the warm-up control when it detects that the impact unit is located on one side of the first position in the first direction.

5. The work machine according to claim 3 , wherein the control unit determines whether the battery is at a low temperature when the operating unit is operated, and performs the warm-up control when it determines that the battery is at a low temperature.

6. The work machine according to claim 2 , wherein the control unit stops the warm-up control when the control unit detects movement of the impact unit during execution of the warm-up control.

7. a temperature sensor for detecting the temperature of the battery; The work machine according to claim 1 , wherein the control unit determines that the battery is at a low temperature when a value detected by the temperature sensor falls below a preset temperature threshold.

8. The work machine according to claim 1 , wherein the control unit determines that the battery is at a low temperature when the output voltage of the battery falls below a predetermined voltage threshold.

9. The work machine according to claim 7 or 8, wherein the control unit changes a criterion for determining whether the battery is at a low temperature depending on the type of the battery.

10. The work machine according to claim 1 , wherein the limit power is a power at which the torque output by the motor is smaller than an actuation start torque required for the actuation unit to transition from a stopped state to an actuation state.

11. 2. The work machine according to claim 1, wherein the control unit supplies the limited power to the motor for a specified time during the warm-up control, and stops the warm-up control if the battery is still at a low temperature after the specified time has elapsed.

12. a switching circuit disposed on a power path supplied from the battery to the motor; 2. The work machine according to claim 1, wherein the control unit supplies limited power from the battery to the motor by duty controlling the switching circuit so that a supply current supplied from the battery to the motor reaches a target value.

13. A motor; a striking portion that strikes the fastener; a biasing portion that biases the striking portion to one side in a first direction; a rotating portion that is engageable with the impact portion and receives a driving force of the motor to move the impact portion to the other side in the first direction against the biasing force of the biasing portion; a battery capable of supplying power to the motor; a control unit that controls the driving of the motor, The control unit performs warm-up control to output power from the battery so that the rotating unit does not operate when the battery is at a low temperature.

14. The work machine according to claim 13 , wherein the control unit, during the warm-up control, causes the battery to output electric power greater than an electric power at which the rotating part does not operate.

15. a one-way clutch that allows the motor to be driven in a forward direction and restricts the motor from being driven in a reverse direction; The work machine according to claim 14, wherein the control unit, in the warm-up control, sets the rotation direction of the motor to a reverse direction and supplies power from the battery to the motor.

16. a load unit capable of consuming power supplied from the battery, the load unit not operating even when the power is consumed; The work machine according to claim 14, wherein the control unit causes the battery to supply power to the load unit during the warm-up control.

Images