Reciprocating tool, and method of controlling electric motor of reciprocating tool

Abstract

The invention provides a reciprocating tool and a method of controlling an electric motor of the reciprocating tool. One aspect of the present invention relates to a reciprocating tool comprising a reciprocating member, an electric motor, a transmission device, a control circuit, a drive circuit, a position detector, and a signal cut-off circuit. The drive circuit (i) receives at least one drive signal, and (ii) drives the electric motor in accordance with the received at least one drive signal. The position detector outputs a position detection signal whenever the reciprocating member reaches a predetermined position during at least one reciprocating operation. The signal cut-off circuit cuts off at least one drive signal for the drive circuit in response to the position detector outputting the position detection signal.

Description

Technical Field

[0001] This invention relates to a reciprocating motion tool. Background Technology

[0002] Japanese Patent Application Publication No. 2019-098456 discloses a punching machine equipped with a control unit, which is configured to stop an electric motor at the point when the striking part reaches the waiting position. The control unit has a microprocessor. Summary of the Invention

[0003] According to the aforementioned injection machine, when the microprocessor's operation is delayed due to the processing load, it may cause a delay in the stopping operation of the electric motor.

[0004] One aspect of the present invention aims to provide a technique that can suppress the stopping delay of an electric motor in a reciprocating motion tool.

[0005] In this invention, the terms "first," "second," etc., are merely intended to distinguish elements from each other, and are not intended to limit the order or number of elements. Therefore, the first element can be called the second element, and similarly, the second element can be called the first element. In addition, the first element can be present without the second element, and similarly, the second element can be present without the first element.

[0006] One aspect of the present invention provides a reciprocating motion tool comprising: a reciprocating component, an electric motor, a transmission device, a control circuit, a drive circuit, a position detector, and a signal cutoff circuit.

[0007] The reciprocating component is configured to reciprocate between the first dead point and the second dead point.

[0008] The electric motor is configured to generate driving force.

[0009] The transmission device is configured to transmit the driving force of the electric motor to the reciprocating component at least during the stroke of the reciprocating component from the second dead point to the first dead point.

[0010] The control circuit is configured to output at least one drive signal for driving the electric motor.

[0011] The drive circuit is configured to: (i) receive the at least one drive signal, and (ii) drive the electric motor according to the received at least one drive signal.

[0012] The position detector is configured to output a position detection signal whenever the reciprocating component reaches a predetermined position during at least one reciprocating motion.

[0013] The signal cutting-off circuit includes wiring logic configured to cut off at least one drive signal for the drive circuit in accordance with the position detection signal output by the position detector.

[0014] In a reciprocating motion tool configured in this way, when the reciprocating component reaches the predetermined position during at least one reciprocating motion, the wiring logic cuts off the at least one drive signal to the drive circuit without any delay in the microprocessor due to processing load. As a result, the drive of the electric motor based on the drive circuit can stop immediately.

[0015] Therefore, according to this reciprocating motion tool, the delay in stopping the electric motor can be suppressed.

[0016] Another aspect of the present invention is to provide a method for controlling an electric motor of a reciprocating tool, the method comprising the following steps:

[0017] At least one drive signal for driving the electric motor is output to the drive circuit of the reciprocating motion tool, wherein the drive circuit is configured to drive the electric motor according to the at least one drive signal.

[0018] The driving force of the electric motor is transmitted to the reciprocating component of the reciprocating motion tool, wherein the reciprocating component is configured to reciprocate between a first dead point and a second dead point, transmitting the driving force at least from the second dead point to the first dead point; and

[0019] The drive of the electric motor is stopped by using wiring logic, wherein the wiring logic is configured to cut off the at least one drive signal for the drive circuit corresponding to the reciprocating component having reached a predetermined position in at least one reciprocating motion.

[0020] According to this method, the stopping delay of the electric motor can be suppressed through the wiring logic. Attached Figure Description

[0021] Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

[0022] Figure 1 This is an external view of the reciprocating motion tool in an exemplary embodiment.

[0023] Figure 2 This is a central longitudinal sectional view of a reciprocating motion tool.

[0024] Figure 3A yes Figure 1 A cross-sectional view of line IIIA-IIIA in the middle. Figure 3B It is a top view of a reciprocating motion tool, including a perspective view of the motor housing.

[0025] Figure 4A -4D represents a sequence of mechanical movements in a reciprocating motion tool.

[0026] Figure 5A -5E represents the movement of the support in a reciprocating motion tool, corresponding to a sequence of mechanical actions.

[0027] Figure 6 It is a circuit diagram that represents the electrical configuration of a reciprocating motion tool.

[0028] Figure 7A This is a block diagram showing the configuration of the first latch circuit. Figure 7B This is a timing diagram representing the operation of the first latch circuit.

[0029] Figure 8 It is a timing diagram that represents a summary of the electrical operation of a reciprocating motion tool.

[0030] Figure 9 It is a flowchart representing the flow of the main program executed by the control circuit.

[0031] Figure 10 It is a flowchart representing the process of motor control execution by the control circuit.

[0032] Figure 11A -11C is a schematic diagram relating to the mechanical configuration of a reciprocating tool in the first variation.

[0033] Figure 12 This is a circuit diagram showing the electrical configuration of the reciprocating motion tool in the first variation.

[0034] Figure 13A This is a block diagram showing the configuration of the third latch circuit. Figure 13B This is a timing diagram showing the operation of the third latch circuit. Detailed Implementation

[0035] 1. Overview of Implementation Methods

[0036] One embodiment may provide a reciprocating motion tool having at least one of the following features:

[0037] • Feature 1: It is configured as a reciprocating component that moves back and forth between the first dead point and the second dead point;

[0038] Feature 2: It is configured as an electric motor that generates driving force;

[0039] • Feature 3: The transmission device of the electric motor is configured to transmit the driving force of the reciprocating component to the reciprocating component at least during the stroke of the reciprocating component from the second dead point to the first dead point;

[0040] Feature 4: Configured (or programmed): a control circuit that outputs at least one drive signal for driving the electric motor;

[0041] Feature 5: It is configured as: (i) receiving the at least one drive signal, and (ii) a drive circuit that drives the electric motor according to the received at least one drive signal;

[0042] • Feature 6: The configuration includes a position detector that outputs a position detection signal whenever the reciprocating component reaches a predetermined position (or a predetermined phase) during at least one reciprocating motion; and

[0043] Feature 7: A signal cutting-off circuit with wiring logic (or hard-wired logic) configured to cut off at least one drive signal to the drive circuit in accordance with the position detection signal output by the position detector.

[0044] In a reciprocating motion tool having at least features 1 to 7, when the reciprocating component reaches the predetermined position during at least one reciprocating motion, the wiring logic cuts off the at least one drive signal to the drive circuit without causing delays in the microprocessor due to processing load. As a result, the drive of the electric motor based on the drive circuit can stop immediately.

[0045] Therefore, according to this reciprocating motion tool, the delay in stopping the electric motor can be suppressed.

[0046] Examples of reciprocating motion tools include: electric nailing machines, electric rebar tying machines, electric rebar cutting machines, electric oil injectors, and electric air pumps. Examples of electric oil injectors include: electric grease guns.

[0047] Examples of electric motors include: DC motors, AC motors, and stepper motors. Examples of DC motors include: brushless DC motors and brushed DC motors.

[0048] Examples of the driving circuits include: full-bridge circuits and half-bridge circuits.

[0049] In one embodiment, the control circuit may also be integrated into a single electronic unit, a single electronic device, or a single circuit board.

[0050] In one embodiment, the control circuit may be a combination of two or more electronic circuits, two or more electronic units, or two or more electronic devices disposed on or within the reciprocating motion tool.

[0051] In one embodiment, the control circuit may also include: a microcomputer (or microcontroller, or microprocessor), wiring logic, an application-specific integrated circuit (ASIC), an application-specific general-purpose product (ASSP), a programmable logic device (PLD) (e.g., a field-programmable gate array (FPGA), etc.), discrete electronic components, and / or combinations thereof.

[0052] In one embodiment, the signal cutoff circuit may include a PLD.

[0053] In addition to having at least one of features 1 to 7, or alternatively, a certain embodiment may also have at least one of the following features:

[0054] Feature 8: The signal interruption circuit is configured to: (i) receive a first logic value and be invalidated, and (ii) receive a second logic value and be validated; and

[0055] Feature 9: The second logic value is the opposite of the first logic value.

[0056] In a reciprocating motion tool having at least features 1 to 9, the signal cutting-off circuit can be enabled or disabled by inputting the first logic value or the second logic value into the signal cutting-off circuit.

[0057] In addition to having at least one of features 1 to 9, or alternatively, a certain embodiment may also have at least one of the following features:

[0058] Feature 10: A manual switch configured for manual operation by the user of the reciprocating motion tool; and

[0059] Feature 11: It is configured as a latching circuit that continuously outputs the second logic value to the signal cut-off circuit in accordance with the position detection signal output by the position detector until the manual switch is manually operated.

[0060] In a reciprocating motion tool having at least features 1 to 11, the signal cutoff circuit can be manually disabled by the user.

[0061] In one embodiment, the latch circuit may include a PLD.

[0062] In addition to having at least one of features 1 to 11, or alternatively, a certain embodiment may also have at least one of the following features:

[0063] Feature 12: A pressing component configured to be pressed onto a workpiece by the user; and

[0064] Feature 13: The manual switch is configured to be manually operated by being pressed against the workpiece by the crimping member.

[0065] In a reciprocating motion tool having at least features 1 to 13, the signal cut-off circuit can be disabled by the user pressing the crimping member onto the workpiece.

[0066] In addition to having at least one of features 1 to 13, or alternatively, a certain embodiment may also have the following features:

[0067] Feature 14: The position detector comprises: (i) a magnet having a first magnetic pole and a second magnetic pole, and (ii) a Hall element configured to detect the first magnetic pole of the magnet, and configured such that, corresponding to the reciprocating component having reached the predetermined position, the Hall element detects the first magnetic pole and outputs the position detection signal.

[0068] Compared to reciprocating tools configured to mechanically detect the position of the reciprocating component, reciprocating tools possessing at least features 1 to 7 and 14 exhibit superior durability. Furthermore, compared to reciprocating tools configured to optically detect the position of the reciprocating component, such reciprocating tools are less susceptible to dust interference during position detection.

[0069] In addition to having at least one of features 1 to 14, or alternatively, a certain embodiment may also have at least one of the following features:

[0070] Feature 15: The transmission device includes a cam (i) having an outer periphery having a plurality of pins arranged in the circumferential direction of the cam, and (ii) being configured to rotate by the driving force of the electric motor;

[0071] Feature 16: The transfer device includes a support that (i) holds the magnet and (ii) is configured to rotate together with the cam; and

[0072] Feature 17: The reciprocating component (i) extends between the first stop and the second stop, (ii) has a plurality of racks in its extending direction, and (iii) is configured to be driven from the second stop toward the first stop by engaging with the plurality of pins respectively through the plurality of racks.

[0073] In a reciprocating motion tool having at least features 1 to 7 and 14 to 17, the reciprocating component is capable of moving from at least the second dead point to the first dead point via the cam. Furthermore, based on the rotational position of the support that rotates together with the cam, the arrival of the reciprocating component toward the predetermined position can be detected.

[0074] In addition to having at least one of features 1 to 17, or alternatively, a certain embodiment may also have the following features:

[0075] Feature 18: The first magnetic pole is directed toward the radially outer side of the support.

[0076] In reciprocating tools having at least features 1-7 and 14-18, the Hall element can be disposed radially outward of the support. As a result, the size of the reciprocating tool in the direction intersecting the radial direction of the support can be reduced.

[0077] In addition to having at least one of features 1 to 18, or alternatively, a certain embodiment may also have at least one of the following features:

[0078] Feature 19: The cam and the bracket are configured to rotate about the same axis; and

[0079] Feature 20: The electric motor has a rotor that acts as the same shaft.

[0080] In addition to having at least one of features 1 to 20, or alternatively, a certain embodiment may also have the following features:

[0081] Feature 21: The support is a non-magnetic body.

[0082] In a reciprocating motion tool having at least features 1-7, 14-17, and 21, the Hall element can easily detect the first magnetic pole.

[0083] In addition to having at least one of features 1 to 21, or alternatively, a certain embodiment may also have the following features:

[0084] Feature 22: The at least one driving signal is at least one pulse width modulation signal.

[0085] In addition to having at least one of features 1 to 22, or alternatively, a certain embodiment may also have at least one of the following features:

[0086] Feature 23: The electric motor is a brushless DC motor equipped with coils 1 to 3.

[0087] Feature 24: The driving circuit includes: (i) at least a portion of a full-bridge circuit and (ii) a first to a sixth semiconductor switch connected to the first to third coils;

[0088] Feature 25: The first to third semiconductor switches are high-side switches in the full-bridge circuit;

[0089] Feature 26: The 4th to 6th semiconductor switches are the low-side switches in the full-bridge circuit;

[0090] Feature 27: The at least one pulse width modulation signal comprises: first to third pulse width modulation signals corresponding to the first to third semiconductor switches, respectively; and

[0091] Feature 28: The wiring logic is configured such that, corresponding to the position detection signal output by the position detector, the first to third pulse width modulation signals are cut off for the driving circuit.

[0092] Examples of brushless DC motors include: 3-phase brushless DC motors and brushless DC motors with 4 or more phases.

[0093] Examples of full-bridge circuits include: 3-phase full-bridge circuits and full-bridge circuits with 4 or more phases.

[0094] In addition to having at least one of features 1 to 28, or alternatively, a certain embodiment may also have at least one of the following features:

[0095] Feature 29: The control circuit is configured (or programmed) to output, in correspondence with the position detection signal output by the position detector, the 4th to 6th pulse width modulation signals that brake the electric motor to the drive circuit; and

[0096] Feature 30: The 4th to 6th pulse width modulation signals correspond to the 4th to 6th semiconductor switches, respectively.

[0097] In a reciprocating motion tool having at least features 1 to 7 and 22 to 30, the electric motor can be stopped immediately when the reciprocating component has reached the specified position.

[0098] In addition to having at least one of features 1 to 30, or alternatively, a certain embodiment may also have the following features:

[0099] Feature 31: The control circuit includes a microcomputer configured (or programmed) to output the first to sixth pulse width modulation signals.

[0100] In addition to having at least one of features 1 to 31, or alternatively, a certain embodiment may also have the following features:

[0101] Feature 32: The specified position corresponds to: (i) a stop position that stops the reciprocating component, and / or (ii) a waiting position that allows the reciprocating component to wait for at least one next reciprocating action.

[0102] In a reciprocating motion tool having at least features 1 to 7, 32, the reciprocating component is capable of stopping at the stop position and / or the waiting position.

[0103] In addition to having at least one of features 1 to 32, or alternatively, a certain embodiment may also have at least one of the following features:

[0104] Feature 33: A cylinder (or chamber) containing compressed gas inside;

[0105] Feature 34: (i) located within the cylinder, (ii) a piston that exerts force on the reciprocating component at the second dead center by the compressed gas; and

[0106] Feature 35: The reciprocating component is configured to be driven from the first dead point to the second dead point by the piston.

[0107] In a reciprocating motion tool having at least features 1 to 7 and 33 to 35, the reciprocating component is able to move from the first dead point to the second dead point by pressure applied from the compressed gas toward the piston.

[0108] Examples of compressed gases include compressed air and compressed inert gases. The compressed air may be compressed dry air. Examples of compressed inert gases include compressed nitrogen and compressed rare gases.

[0109] In addition to having at least one of features 1 to 35, or alternatively, a certain embodiment may also have the following features:

[0110] Feature 36: The reciprocating component is configured such that (i) it is located at the first dead center, corresponding to the piston being located at its top dead center, and (ii) it is located at the second dead center, corresponding to the piston being located at its bottom dead center.

[0111] In a reciprocating motion tool having at least features 1 to 7 and 33 to 36, the maximum pressure of the compressed gas can be applied to the reciprocating component, thereby enabling the reciprocating component to move from the first dead point to the second dead point. Furthermore, the reciprocating component moving from the second dead point to the first dead point can be decelerated by the pressure of the compressed gas.

[0112] One implementation may provide a method having at least one of the following features:

[0113] Feature 37: Outputting at least one drive signal of the electric motor used to drive the reciprocating motion tool to the drive circuit of the reciprocating motion tool;

[0114] Feature 38: The drive circuit is configured to drive the electric motor according to the at least one drive signal;

[0115] Feature 39: The driving force of the electric motor is transmitted to the reciprocating component of the reciprocating motion tool;

[0116] Feature 40: The reciprocating component is configured to reciprocate between the first dead point and the second dead point;

[0117] Feature 41: The driving force is transmitted at least from the second dead point to the first dead point;

[0118] Feature 42: The electric motor is stopped using wiring logic; and

[0119] Feature 43: The wiring logic is configured such that, corresponding to the reciprocating component having reached a specified position (or specified phase) in at least one reciprocating action, the at least one drive signal is cut off for the drive circuit.

[0120] According to a method having at least features 37 to 43, the stopping operation delay of the electric motor can be suppressed through the wiring logic.

[0121] In one embodiment, features 1 to 43 can be combined arbitrarily.

[0122] In one embodiment, any one of features 1 to 43 may be excluded.

[0123] 2. Specific exemplary implementation methods

[0124] The following describes specific exemplary embodiments. These specific exemplary embodiments provide... Figure 1 The reciprocating motion tool 1 shown.

[0125] The terms "up," "down," "front," "back," "left," and "right" used in the following description or accompanying drawings are merely for the purpose of making the structure of the reciprocating motion tool 1 easier to understand, and are not intended to limit the orientation of the reciprocating motion tool 1. The reciprocating motion tool 1 can be configured in all orientations.

[0126] 2-1. Overall Structure of Reciprocating Motion Tools

[0127] like Figure 1 As shown, the reciprocating tool 1 in this embodiment is an electric nailing machine configured to drive nails into a workpiece. Examples of nails used in the reciprocating tool 1 include U-shaped nails, pins, concealed nails, and foot nails. In other embodiments, the reciprocating tool 1 can be any other type of reciprocating tool such as an electric rebar tying machine, an electric rebar cutter, an electric oiler, and an electric air pump.

[0128] The reciprocating tool 1 includes a housing 2. The housing 2 includes a drive assembly receiving portion 3 extending from its rear end toward its front end (i.e., in the direction of nail ejection). The reciprocating tool 1 has an ejection portion 4 in front of the drive assembly receiving portion 3. The ejection portion 4 includes a guide portion 5 configured to guide the nail ejected from the reciprocating tool 1 toward a workpiece. In this embodiment, the guide portion 5 protrudes from the interior of the drive assembly receiving portion 3 toward the front of the reciprocating tool 1. The ejection portion 4 includes a crimping member (or contactor) 6 configured to be crimped onto the workpiece. The crimping member 6 is positioned above the guide portion 5 and protrudes forward in the reciprocating tool 1. The ejection portion 4 includes a connecting mechanism 7 connected to the crimping member 6.

[0129] The outer casing 2 includes a gripping portion 8 extending downward from approximately the center of the insertion component receiving portion 3. The gripping portion 8 is configured to be held by the user of the reciprocating motion tool 1 with one hand. The gripping portion 8 has a trigger 9 on its upper front side. The trigger 9 is configured to be pulled by the user's finger (e.g., index finger).

[0130] The housing 2 includes a motor housing 10 extending downward from the front of the component receiving portion 3. The housing 2 also includes a battery mounting portion 11 extending from the lower end of the motor housing 10 toward the lower end of the grip portion 8. The battery mounting portion 11 is configured such that the battery pack 12 can be detachably mounted to the battery mounting portion 11.

[0131] The reciprocating tool 1 has a nail box 13 on the left side of the housing 2, extending from the lower part of the guide portion 5 to the lowermost end of the reciprocating tool 1. The nail box 13 is configured to feed one or more nails housed therein into the guide portion 5 one by one. In this embodiment, the nail box 13 is tilted rearward.

[0132] like Figure 2 As shown, the drive assembly receiving section 3 receives the drive assembly 14, which is configured to drive in a nail.

[0133] The injection assembly 14 includes a cylinder 15 extending from the rear end of the injection assembly housing 3 toward approximately the center. The cylinder 15 contains compressed gas. In this embodiment, the compressed gas is compressed, dried air. In other embodiments, the compressed gas may be compressed nitrogen or other compressed inert gases such as rare gases.

[0134] The cylinder 15 has a piston 16 inside. The piston 16 is configured to move between the rear end and the front end of the cylinder 15 while sealing the cylinder 15. The injection assembly 14 has a buffer 17 at the front end of the cylinder 15. The buffer 17 is configured to receive the piston 16 that has reached the front end of the cylinder 15 and stop the piston 16.

[0135] The injection assembly 14 includes a reciprocating member (or driver) 18 connected to the piston 16 via a buffer 17. The reciprocating member 18 extends from the piston 16 toward the front end of the guide portion 5. The reciprocating member 18 is configured to move toward the front end of the guide portion 5 by pressure applied to the piston 16 from compressed gas. In other words, the piston 16 exerts force on the reciprocating member 18 toward the front end of the guide portion 5 by compressed gas. In this embodiment, the reciprocating member 18 has the following length: (i) the front end of the reciprocating member 18 reaches the front end of the cylinder 15 (i.e., the bottom dead center of the piston 16), and (ii) the front end of the reciprocating member 18 retracts into the injection assembly receiving portion 3 when the piston 16 reaches the rear end of the cylinder 15 (i.e., the top dead center of the piston 16).

[0136] The linking mechanism 7 of the injection section 4 has a spring 19 inside the injection component receiving section 3. The linking mechanism 7 is configured such that it applies force to the pressing member 6 in the forward direction by means of the spring 19, and on the other hand, corresponding to the front end of the pressing member 6 being pressed to the workpiece, it causes the pressing member 6 to move in the rear direction of the reciprocating motion tool 1.

[0137] The insertion component receiving section 3 houses the contactor switch 20 above the reciprocating component 18. The contactor switch 20 is configured such that when the crimping component 6 is crimped to the workpiece, it is pushed (i.e. turned on) by the linking mechanism 7.

[0138] The gripping part 8 houses the trigger switch 21. The trigger switch 21 is configured to be pushed (i.e., turned on) when the trigger 9 is pulled. The trigger switch 21 is configured to be turned off when the user's finger is removed from the trigger 9.

[0139] The battery assembly 11 houses the connector 22, which is configured to be detachably connected to the battery pack 12 assembled in the battery assembly 11. The battery assembly 11 houses the controller 23 above the connector 22.

[0140] The motor housing 10 houses the electric motor 24 at its lower part. In this embodiment, the electric motor 24 is a 3-phase brushless DC motor. In other embodiments, the electric motor 24 may be: a single-phase brushless DC motor, a 2-phase brushless DC motor, a 4-phase or higher brushless DC motor, a brushed DC motor, an AC motor, or a stepper motor.

[0141] The motor housing 10 houses the transmission device 25 above the electric motor 24. The transmission device 25 is connected to the rotor 26 of the electric motor 24 and is configured to transmit the driving force of the electric motor 24 to the reciprocating component 18.

[0142] More specifically, the transmission device 25 includes a reducer 27, which (i) has a preset reduction ratio and (ii) is configured to convert the driving force of the electric motor 24 into a reduced output and transmit it to the reciprocating member 18. Therefore, the transmission device 25 can transmit torque proportional to the reduction ratio of the reducer 27 to the reciprocating member 18. In this embodiment, the reducer 27 is a concentric shaft gear reducer, more specifically, a planetary gear reducer. In other embodiments, the reducer 27 may be a parallel shaft gear reducer or an orthogonal shaft gear reducer, depending on the structure of the transmission device 25.

[0143] like Figure 3A As shown, the transmission device 25 has a cam 28 above the reducer 27. In this embodiment, the cam 28 is in the shape of a circular plate. The cam 28 has pins 29a to 29i 1 to 9 along its circumferential direction on its outer periphery. The cam 28 is configured to rotate in response to the output of the reducer 27. More specifically, when viewed from above the reciprocating tool 1, the cam 28 rotates counterclockwise around the rotor 26 of the electric motor 24.

[0144] The reciprocating component 18 has racks 30a to 30i from the first to the ninth position on its right side. The racks 30a to 30i are arranged in a row along the extending direction of the reciprocating component 18. The racks 30a to 30i correspond to pins 29a to 29i from the first to the ninth position, respectively. The pins 29a to 29i engage with the racks 30a to 30i to transmit the driving force of the electric motor 24 to the reciprocating component 18.

[0145] like Figure 3B As shown, the transmission device 25 has a support 31 above the cam 28. In this embodiment, the support 31 is circular. The support 31 is a non-magnetic body. The support 31 has a first magnet 32 ​​on its upper surface. In this embodiment, the first magnet 32 ​​is arranged on the upper surface of the support 31 with its S pole facing radially outward. In other embodiments, the first magnet 32 ​​may be arranged on the upper surface of the support 31 with its N pole facing radially outward.

[0146] The support 31 has a second magnet 33 on its upper surface. In this embodiment, the second magnet 33 is disposed on the upper surface of the support 31 with its N pole facing radially outward. In other embodiments, the second magnet 33 may be disposed on the upper surface of the support 31 with its S pole facing radially outward.

[0147] The bracket 31 is configured to rotate by receiving the output of the reducer 27. More specifically, when viewed from above the reciprocating tool 1, the bracket 31, together with the cam 28, rotates counterclockwise around the rotor 26 of the electric motor 24.

[0148] The motor housing 10 has a Hall IC 34 on its right inner wall. The Hall IC 34 is opposite to the outer periphery of the bracket 31. The Hall IC 34 is configured to: (i) detect the S pole of the first magnet 32 ​​when the first magnet 32 ​​approaches the Hall IC 34, and (ii) detect the N pole of the second magnet 33 when the second magnet 33 approaches the Hall IC 34.

[0149] The outer casing 2 has a main power switch 36 on its upper rear left side, configured to be pushed by the user to turn the power of the reciprocating motion tool 1 on or off.

[0150] The housing 2 includes a mode selection switch 37 adjacent to the main power switch 36. The mode selection switch 37 is configured such that the user can push and press it to select the operating mode of the reciprocating motion tool 1.

[0151] The housing 2 has a first display 38 between the main power switch 36 and the mode selection switch 37. The first display 38 is lit (i) when the reciprocating motion tool 1 is set to the single-shot mode described later, or (ii) when the reciprocating motion tool 1 malfunctions.

[0152] The housing 2 includes a second display 39 adjacent to the first display 38. The second display 39 is illuminated (i) when the reciprocating motion tool 1 is set to the continuous firing mode described later, or (ii) when the reciprocating motion tool 1 malfunctions.

[0153] 2-2. Mechanical motion of reciprocating motion tools

[0154] 2-2-1. Mechanical movement of reciprocating components and cams

[0155] Reference Figures 4A to 4D This explains the operation of the reciprocating component 18 and the cam 28. In most cases, when processing a workpiece, the user uses the reciprocating tool 1 with its front end facing downwards. Therefore, in... Figures 4A to 4D In the middle, the front end of the reciprocating motion tool 1 faces downward.

[0156] like Figure 4A As shown, the reciprocating component 18 is typically held in a waiting position. This waiting position is set near the top dead center of the reciprocating component 18. In this embodiment, the waiting position is a position where the reciprocating component 18 stops, and also a position where the reciprocating component 18 waits for its next reciprocating motion. In the waiting position, the first to eighth pins 29a to 29h of the cam 28 disengage from the first to eighth racks 30a to 30h of the reciprocating component 18, and only the ninth pin 29i of the cam 28 engages with the ninth rack 30i of the reciprocating component 18. At this time, the piston 16 is near its top dead center.

[0157] When the electric motor 24 is driven, causing the cam 28 to rotate counterclockwise, as Figure 4B As shown, the reciprocating component 18 is driven from the waiting position toward its top dead center. At this time, the piston 16 also reaches its top dead center.

[0158] When the reciprocating component 18 reaches its top dead center, causing the 9th pin 29i to disengage from the 9th rack 30i, as Figure 4CAs shown, the reciprocating component 18 is driven to its lower dead center by the pressure of the compressed gas applied from the piston 16. As a result, the nail supplied to the guide 5 is struck by the reciprocating component 18 and driven into the workpiece. When the reciprocating component 18 reaches its lower dead center, the piston 16 also reaches its lower dead center. The cam 28 continues to rotate after the 9th pin 29i disengages from the 9th rack 30i, and the 1st to 9th pins 29a to 29i re-engage with the 1st to 9th racks 30a to 30i respectively. Moreover, as Figure 4D As shown, the reciprocating component 18 returns to the waiting position, and the cam 28 is stopped.

[0159] 2-2-2. Mechanical movement of the stent

[0160] When the electric motor 24 is driven, the bracket 31 and the cam 28 move together as... Figures 5A-5E Rotate as shown. Figures 5A-5C 5E and Figures 4A-4D Correspondingly. Figure 5D Indicates: Cam 28 is in position (i) Figure 4C The rotational position of the cam 28 shown is related to (ii). Figure 4D The rotational position of the bracket 31 between the rotational positions of the cam 28 shown.

[0161] The Hall IC 34 includes a first Hall element 34a. In this embodiment, the first Hall element 34a is configured to detect the S pole of the first magnet 32. In other embodiments, when the first magnet 32 ​​is disposed on the upper surface of the support 31 with its N pole facing radially outward from the support 31, the first Hall element 34a may be configured to detect the N pole of the first magnet 32.

[0162] The Hall IC 34 includes a second Hall element 34b. In this embodiment, the second Hall element 34b is configured to detect the N pole of the second magnet 33. In other embodiments, when the second magnet 33 is disposed on the upper surface of the support 31 with its S pole facing radially outward from the support 31, the second Hall element 34b may be configured to detect the S pole of the second magnet 33.

[0163] The first magnet 32 ​​is in the rotation direction of the bracket 31 ( Figures 5A-5E It is positioned in front of the second magnet 33 (rotating counterclockwise).

[0164] To be more specific, such as Figure 5D As shown, the first magnet 32 ​​is positioned on the upper surface of the bracket 31 such that its S pole is opposite to the first Hall element 34a at the moment when it begins to prepare to stop the cam 28.

[0165] like Figure 5AAs shown in 5E, the second magnet 33 is arranged on the upper surface of the bracket 31 such that its N pole is opposite to the second Hall element 34b when the reciprocating component 18 is in the waiting position.

[0166] 2-3. Electrical Configuration of Reciprocating Motion Tools

[0167] like Figure 6 As shown, the electric motor 24 includes first to third coils 24a to 24c, which are respectively associated with the three phases (i.e., U-phase, V-phase, and W-phase) of the electric motor 24. The first to third coils 24a to 24c are configured to be energized sequentially to generate a rotating magnetic field. In this embodiment, the first to third coils 24a to 24c are connected in a delta configuration. In other embodiments, the first to third coils 24a to 24c may be connected in a star configuration (or a Y configuration). The rotor 26 (i) includes a first pole 26a and a second pole 26b, and (ii) is configured to rotate by receiving the rotating magnetic field generated by the first to third coils 24a to 24c through the first pole 26a and the second pole 26b.

[0168] The electric motor 24 includes a rotational position detector 24d. The rotational position detector 24d is configured to output first to third pulse signals (or rectangular wave signals) to the controller 23 corresponding to the rotational position of the rotor 26. In this embodiment, the rotational position detector 24d is a Hall sensor. In this embodiment, the first to third pulse signals reverse from positive (or HIGH) to negative (or LOW) or vice versa whenever the rotor 26 rotates by an electrical angle of 180 degrees. The first to third pulse signals have a phase difference of 60 degrees between them. In other embodiments, the rotational position detector 24d may be configured to output one pulse signal to the controller 23 each time the rotor 26 rotates by an electrical angle of 60 degrees, instead of the first to third pulse signals. Furthermore, in other embodiments, the rotational position detector 24d may be configured to output first to third sine wave signals to the controller 23, instead of the first to third pulse signals. In this case, the controller 23 may include a waveform conversion circuit configured to convert the first to third sine wave signals into first to third pulse signals. Furthermore, in other embodiments, the rotary position detector 24d may be a pulse encoder.

[0169] The reciprocating tool 1 includes a power line Lp extending from the positive terminal of the battery pack 12 mounted in the battery assembly 11 to the controller 23. The reciprocating tool 1 also includes a grounding wire Ln extending from the negative terminal of the battery pack 12 mounted in the battery assembly 11 to the controller 23. The grounding wire Ln is connected to the grounding terminal of the reciprocating tool 1 on the controller 23. The battery pack 12 applies its output voltage (hereinafter referred to as battery voltage) between the power line Lp and the grounding wire Ln.

[0170] The controller 23 includes a control circuit 51. In this embodiment, the control circuit 51 includes a microcomputer 51a. The microcomputer 51a includes a CPU (not shown), a ROM (not shown), a RAM (not shown), an analog-to-digital (A-D) converter (not shown), an input port (not shown), and an output port (not shown). In other embodiments, the control circuit 51 may include an additional microcomputer. Furthermore, in other embodiments, the control circuit 51 may include, in addition to the microcomputer 51a, or instead of it, a logic circuit (or wiring logic connection) including two or more electronic components. Furthermore, in other embodiments, the control circuit 51 may include, in addition to the microcomputer 51a, or instead of it, an ASIC and / or an ASSP. Furthermore, in other embodiments, the control circuit 51 may include, in addition to the microcomputer 51a, or instead of it, a PLD capable of constructing reconfigurable logic circuits. Examples of PLDs include FPGAs.

[0171] The control circuit 51 is connected to the rotary position detector 24d. The control circuit 51 is configured to: (i) receive the first to third pulse signals from the rotary position detector 24d, and (ii) identify the rotational position of the rotor 26 based on the received first to third pulse signals.

[0172] The control circuit 51 is connected to the main power switch 36. The main power switch 36 includes: (i) a first contact connected to the ground terminal of the reciprocating tool 1, and (ii) a second contact connected to the control circuit 51. Therefore, the main power switch 36 is configured to output a first negative logic signal to the control circuit 51 in response to the main power switch 36 being pushed (i.e., turned on). The control circuit 51 is configured to recognize that the main power switch 36 has been turned on based on the first negative logic signal received by the control circuit 51 from the main power switch 36.

[0173] Control circuit 51 is connected to mode selection switch 37. Mode selection switch 37 includes: (i) a first contact connected to the ground terminal of reciprocating tool 1, and (ii) a second contact connected to control circuit 51. Therefore, mode selection switch 37 is configured to output a second negative logic signal to control circuit 51 in response to mode selection switch 37 being pushed (i.e., turned on). Control circuit 51 is configured to recognize that mode selection switch 37 has been turned on based on receiving the second negative logic signal from mode selection switch 37.

[0174] Control circuit 51 is connected to contactor switch 20. Contactor switch 20 includes: (i) a first contact connected to the ground terminal of reciprocating tool 1, and (ii) a second contact connected to control circuit 51. Therefore, contactor switch 20 is configured to output a third negative logic signal to control circuit 51 in response to being pressed against the workpiece by crimping member 6 (i.e., being turned on). Control circuit 51 is configured to recognize that contactor switch 20 has been turned on based on the third negative logic signal received from contactor switch 20.

[0175] The control circuit 51 is connected to the first Hall element 34a. The first Hall element 34a is configured to output a first position detection signal to the control circuit 51 in accordance with the detection of the S pole of the first magnet 32 ​​by the first Hall element 34a. In this embodiment, the first position detection signal is a negative logic signal. In other embodiments, the first position detection signal can be a positive logic signal.

[0176] The control circuit 51 is connected to the second Hall element 34b. The second Hall element 34b is configured to output a second position detection signal to the control circuit 51 in accordance with the detection of the N pole of the second magnet 33 by the second Hall element 34b. In this embodiment, the second position detection signal is a negative logic signal. In other embodiments, the second position detection signal can be a positive logic signal.

[0177] The control circuit 51 is configured to (i) be connected to the first display 38, and (ii) output a first lighting signal to the first display 38. The first display 38 is configured to receive the first lighting signal from the control circuit 51 and then light up.

[0178] The control circuit 51 is configured to (i) be connected to the second display 39, and (ii) output the second lighting signal to the second display 39. The second display 39 is configured to receive the second lighting signal from the control circuit 51 and then light up.

[0179] The controller 23 includes a power supply circuit 52 connected to: (i) the first contact of the main power switch 36, (ii) the control circuit 51, (iii) the power line Lp, and (iv) a ground terminal. The main power switch 36 is configured to output a first negative logic signal to the power supply circuit 52, in addition to the control circuit 51. The control circuit 51 is configured to output a remote control (RC) signal to the power supply circuit 52. In this embodiment, the RC signal is a negative logic signal. In other embodiments, the RC signal can be a positive logic signal.

[0180] The power supply circuit 52 is configured to maintain its on state during either (i) when receiving a first negative logic signal from the main power switch 36, or (ii) when receiving an RC signal from the control circuit 51. In its on state, the power supply circuit 52 generates a fixed DC voltage (hereinafter referred to as the power supply voltage) Vc based on the battery voltage. The power supply voltage Vc generated by the power supply circuit 52 is supplied via a path not shown to various circuits on the rotary position detector 24d, the first Hall element 34a, the second Hall element 34b, the first display 38, the second display 39, and the controller 23.

[0181] The controller 23 includes a voltage measurement circuit 53, which is configured to: (i) measure the battery voltage on the power line Lp, and (ii) output a battery voltage signal to the control circuit 51. The battery voltage signal is an analog signal having a voltage corresponding to the measured battery voltage.

[0182] The controller 23 includes a first latch circuit 54 connected to: (i) the first contact of the contactor switch 20 and (ii) the second Hall element 34b. The first latch circuit 54 is configured to: (i) maintain its output (POS) in negative (or LOW) corresponding to the falling edge of the second position detection signal output from the second Hall element 34b, and (ii) reset its output to positive (or HIGH) corresponding to the third negative logic signal output from the contactor switch 20.

[0183] The controller 23 includes a drive circuit 55 connected to the control circuit 51. The control circuit 51 is configured to output pulse width modulation (PWM) signals from the first to the sixth pulse width modulation (PWM) signals to the drive circuit 55. The first to the sixth PWM signals share the same cycle. The drive circuit 55 is configured to drive the electric motor 24 according to the first to the sixth PWM signals received from the control circuit 51.

[0184] More specifically, the drive circuit 55 includes a signal amplifier (or level converter) 55a, which is configured to amplify the first to sixth PWM signals received from the control circuit 51.

[0185] The drive circuit 55 includes: switches Q1 to Q6 forming a 3-phase full-bridge circuit. Switches Q1 to Q3 are connected to: (i) the power line Lp and (ii) coils 24a to 24c, respectively, in a manner that functions as high-side switches of the 3-phase full-bridge circuit. Switches Q4 to Q6 are connected to: (i) coils 24a to 24c, respectively, in a manner that functions as low-side switches of the 3-phase full-bridge circuit, respectively, and (ii) the ground terminal.

[0186] Switches Q1 to Q6 are configured to receive the PWM signals amplified by signal amplifier 55a, respectively, and transition to their respective on or off states. In this embodiment, switches Q1 to Q6 are n-channel metal-oxide-semiconductor field-effect transistors (MOSFETs). In other embodiments, at least one of switches Q1 to Q6 may be a semiconductor switch of other types, including junction field-effect transistors (JFETs), bipolar transistors, and insulated-gate bipolar transistors (IGBTs). Furthermore, in other embodiments, each or at least one of switches Q1 to Q6 may be a mechanical relay.

[0187] The controller 23 includes a first signal cutoff circuit 56 configured to cut off the first to third PWM signals output from the control circuit 51. More specifically, the first signal cutoff circuit 56 is configured to: (i) be disabled (disabled) when the output (POS) of the first latch circuit 54 is positive, and (ii) be enabled (enabled) when the output of the first latch circuit 54 is negative. When the first signal cutoff circuit 56 is disabled, the first to third PWM signals are transmitted to the drive circuit 55 via the first signal cutoff circuit 56. When the first signal cutoff circuit 56 is enabled, the first to third PWM signals are cut off from the drive circuit 55 via the first signal cutoff circuit 56.

[0188] In this embodiment, the first signal cutoff circuit 56 includes wiring logic. More specifically, the first signal cutoff circuit 56 includes first to third AND gates 56a to 56c. The first to third AND gates 56a to 56c are configured to: (i) transmit the first to third PWM signals to the drive circuit 55 during the period when the output of the first latch circuit 54 is positive; and (ii) cut off the first to third PWM signals to the drive circuit 55 by setting their respective outputs to negative (or LOW) during the period when the output of the first latch circuit 54 is negative.

[0189] The controller 23 includes a current measuring circuit 57, which is configured to: (i) connect the drive circuit 55 to the ground terminal, and (ii) measure the magnitude of the current flowing through the electric motor 24 (hereinafter referred to as the motor current). The current measuring circuit 57 includes a shunt resistor R1. The shunt resistor R1 includes: (i) a first terminal connected to the fourth to sixth switches Q4 to Q6, and (ii) a second terminal connected to the ground terminal.

[0190] The current measuring circuit 57 includes a differential amplifier OP1, which is configured to: (i) measure the magnitude of the motor current flowing through the shunt resistor R1, and (ii) output a current measuring signal. More specifically, the differential amplifier OP1 is configured to amplify the voltage across the shunt resistor R1 to generate the current measuring signal. Therefore, the current measuring signal is an analog signal having a voltage corresponding to the magnitude of the motor current. The differential amplifier OP1 can be either an open-loop configuration without a negative feedback circuit from its output to its input, or a closed-loop configuration with such a negative feedback circuit. The control circuit 51 is configured to receive the current measuring signal.

[0191] The current measuring circuit 57 includes a comparator CP1, which is configured to detect when the trigger switch 21 is turned on. More specifically, the comparator CP1 is configured to: (i) compare the voltage of the current measuring signal with a preset reference voltage Vref; (ii) set its output to positive (or HIGH) when the voltage of the current measuring signal is greater than the reference voltage Vref; and (iii) set its output to negative (or LOW) when the voltage of the current measuring signal is less than or equal to the reference voltage Vref. The reference voltage Vref is equal to or approximately equal to the voltage of the current measuring signal when insufficient motor current flows through the electric motor 24, as described later.

[0192] The controller 23 includes a second latch circuit 58, which is configured to maintain the output (CUR) of the comparator CP1 in a positive (or HIGH) state corresponding to the output of the comparator CP1 being positive. The second latch circuit 58 is configured to maintain the output of the comparator CP1 in a positive state for at least a time equal to or longer than the period of the first to sixth PWM signals (e.g., 100 milliseconds) whenever the output of the comparator CP1 transitions from negative to positive. The control circuit 51 is configured to receive the output of the second latch circuit 58.

[0193] The trigger switch 21 connects (i) the power line Lp to (ii) the first to third switches Q1 to Q3. More specifically, the trigger switch 21 includes (i) a first contact connected to the power line Lp and (ii) a second contact connected to the first to third switches Q1 to Q3, and is configured to either connect or disconnect the power line Lp from the first to third switches Q1 to Q3.

[0194] The controller 23 includes a seventh switch Q7 connected to (i) the first contact and (ii) the second contact of the trigger switch 21. The seventh switch Q7 is configured such that (i) in its on state, it connects the first and second contacts of the trigger switch 21, and (ii) in its off state, it disconnects the first and second contacts of the trigger switch 21. Therefore, the seventh switch Q7 is configured such that (i) while the trigger switch 21 is in its off state and the seventh switch Q7 is in its on state, the power line Lp is connected to the first to third switches Q1 to Q3 via the seventh switch Q7, and (ii) while the trigger switch 21 is in its off state and the seventh switch Q7 is also in its off state, the power line Lp is disconnected from the first to third switches Q1 to Q3. In this embodiment, the seventh switch Q7 is an n-channel MOSFET. In other embodiments, the seventh switch Q7 can be other types of semiconductor switches, including JFETs, bipolar transistors, IGBTs, and SSRs. Furthermore, in other embodiments, the seventh switch Q7 can be a mechanical relay.

[0195] The control circuit 51 is configured to output (i) a switch-on signal to turn on the 7th switch Q7 and (ii) a switch-off signal to turn off the 7th switch Q7. In this embodiment, the switch-on signal is a positive logic signal and the switch-off signal is a negative logic signal. In other embodiments, the switch-on signal can be a negative logic signal and the switch-off signal can be a positive logic signal.

[0196] The controller 23 includes a second signal cutoff circuit 59, which is configured to cut off the switch-on signal output from the control circuit 51. More specifically, the second signal cutoff circuit 59 is configured to: (i) be disabled (disabled) when the output (CUR) of the second latch circuit 58 is positive, and (ii) be enabled (enabled) when the output of the second latch circuit 58 is negative. When the second signal cutoff circuit 59 is disabled, the switch-on signal is transmitted to the seventh switch Q7 via the second signal cutoff circuit 59. When the second signal cutoff circuit 59 is enabled, the switch-on signal is cut off for the seventh switch Q7 via the second signal cutoff circuit 59.

[0197] In this embodiment, the second signal cutoff circuit 59 includes wiring logic. More specifically, the second signal cutoff circuit 59 includes a fourth AND gate 59a. The fourth AND gate 59a is configured to: (i) transmit a switch-on signal to the seventh switch Q7 during the period when the output of the second latch circuit 58 is positive, and (ii) cut off the switch-on signal for the seventh switch Q7 by setting the output of the fourth AND gate 59a to negative (or LOW) during the period when the output of the second latch circuit 58 is negative.

[0198] The controller 23 includes an electrolytic capacitor C1 configured to supply a stable motor current to the electric motor 24. The electrolytic capacitor C1 includes: (i) an anode connected to the first contact of the trigger switch 21, and (ii) a cathode connected to ground. In other embodiments, the electrolytic capacitor C1 may be removed.

[0199] 2-4. Details of the structure and operation of the first latch circuit

[0200] like Figure 7A As shown, the first latch circuit 54 has a one-shot pulse generation circuit 54a at its input section. The one-shot pulse generation circuit 54a is connected to the second Hall element 34b. Figure 7B As shown, the single pulse generation circuit 54a is configured to generate and output a single pulse with a pre-specified pulse width when the output of the second Hall element 34b shifts from positive to negative (i.e., corresponding to the falling edge of the second position detection signal).

[0201] like Figure 7A As shown, the first latching circuit 54 has a reset circuit 54b at its input section. The reset circuit 54b is connected to the contactor switch 20. Figure 7B As shown, the reset circuit 54b is configured to: (i) set its output to positive when the contactor switch 20 is in the open state, and (ii) set its output to negative when the contactor switch 20 is in the closed state.

[0202] like Figure 7A As shown, the first latch circuit 54 includes a holding circuit 54c at its output stage. The holding circuit 54c is connected to the single-pulse generation circuit 54a and the reset circuit 54b. Figure 7B As shown, the holding circuit 54c is configured to: (i) hold its output (POS) negative at the rising edge of the pulse voltage output from the single pulse generation circuit 54a, and (ii) reset its output to positive corresponding to the shift of the output of the reset circuit 54b from positive to negative.

[0203] 2-5. Electrical Actions of Reciprocating Motion Tools

[0204] The electrical configuration described above operates as follows.

[0205] like Figure 8 As shown, when the power circuit 52 is on, once the pressing member 6 is pressed against the workpiece, causing the contactor switch 20 to turn on, the output (POS) of the first latching circuit 54 will be held positive (or HIGH), and the first signal cutoff circuit 56 will be deactivated. The control circuit 51 identifies the rotational position of the rotor 26 based on the first to third pulse signals received from the rotational position detector 24d up to this point. The control circuit 51 selects one of (i) high-side switches and one of (ii) low-side switches according to the first table stored in the ROM, and outputs the PWM signal corresponding to these selected switches. The first table determines the combination of high-side switches and low-side switches that should be selected in association with the rotational position of the rotor 26. The first table is set to select the combination of high-side switches and low-side switches that would cause the rotor 26 to fail to rotate. More specifically, in this embodiment, the first table is set to select the following combination: (i) a combination of a high-side switch and a low-side switch that generates a magnetic field that pulls the first pole 26a toward the coil (any one of the first to third coils 24a to 24c) opposite to the first pole 26a of the rotor 26, or (ii) a combination of a high-side switch and a low-side switch that generates a magnetic field that pulls the second pole 26b toward the coil (any one of the first to third coils 24a to 24c) opposite to the second pole 26b of the rotor 26.

[0206] The corresponding PWM signals each have an initial duty cycle. The initial duty cycle is a duty cycle greater than zero but insufficient to start the electric motor 24 (e.g., 10%). With this initial duty cycle, the selected high-side switch and the selected low-side switch supply the insufficient motor current to one of the corresponding coils 24a to 24c from the first to the third coils. The rotor 26 is configured such that it does not rotate due to the insufficient motor current.

[0207] When trigger switch 21 is turned on and insufficient motor current flows, the output (CUR) of the second latch circuit 58 is kept positive (or HIGH), and the second signal cutoff circuit 59 is disabled. Once the control circuit 51 recognizes that trigger switch 21 has been turned on based on the positive output of the second latch circuit 58, a switch-on signal is transmitted from the control circuit 51 to the seventh switch Q7, and the seventh switch Q7 is then turned on. Furthermore, the control circuit 51 performs a soft start. During the soft start, the control circuit 51 selects (i) one of the high-side switches and (ii) one of the low-side switches according to a second table stored in the ROM, and outputs the PWM signal corresponding to these selected switches. The second table determines the combination of high-side and low-side switches to be selected in association with the rotational position of the rotor 26. The second table is set to select a combination of high-side and low-side switches that facilitates the rotation of the rotor 26. During the soft start, the control circuit 51 gradually increases the duty cycle of the corresponding PWM signals.

[0208] When the soft start is complete, the control circuit 51 sets the duty cycle of the PWM signal corresponding to the selected high-side switch and the selected low-side switch to 100%.

[0209] When the first Hall element 34a detects that the reciprocating component 18 has reached the stop preparation position, the control circuit 51 begins to prepare to stop the electric motor 24. Specifically, the control circuit 51 calculates the remaining drive time of the electric motor 24. When the calculated remaining drive time has elapsed, the control circuit 51 sets the duty cycle of all PWM signals from the first to the sixth to 0%, causing the electric motor 24 to transition to a free-running state.

[0210] Next, when the second Hall element 34b detects that the reciprocating component 18 has reached the waiting position, (i) the output (POS) of the first latch circuit 54 is reset to negative (or LOW), (ii) the first signal cutoff circuit 56 is activated, and (iii) the first to third PWM signals are cut off for the first to third switches Q1 to Q3 via the first signal cutoff circuit 56. Almost simultaneously, the control circuit 51 outputs a PWM signal with a specified duty cycle (e.g., 100%) to at least two of the fourth to sixth switches Q4 to Q6 to cause the electric motor 24 to undergo short-circuit braking (or regenerative braking). Accordingly, the electric motor 24 stops when short-circuit braking occurs.

[0211] When the control circuit 51 detects that the electric motor 24 has stopped based on the first to third pulse signals, it transmits a switch-off signal from the control circuit 51 to the seventh switch Q7, thereby turning off the seventh switch Q7.

[0212] 2-6. Movement patterns of reciprocating motion tools

[0213] As described above, the reciprocating motion tool 1 is configured to switch between single-shot mode and burst-fire mode. The general outline of the operation of the reciprocating motion tool 1 in single-shot mode and burst-fire mode is as follows.

[0214] In single-shot mode, when the trigger 9 is pulled while the crimping component 6 is being crimped onto the workpiece, the reciprocating tool 1 will drive a nail into the workpiece.

[0215] In single-shot mode, when the pressing component 6 is pressed onto the workpiece while the trigger 9 is pulled, the reciprocating motion tool 1 does not drive the nail in.

[0216] In continuous firing mode, with trigger 9 already pulled, the reciprocating tool 1 will drive a nail into the workpiece whenever the pressing part 6 is pressed against it.

[0217] 2-7. Processing performed by the control circuit

[0218] The following describes in detail the processing performed by the control circuit 51 (more specifically, the microcomputer 51a).

[0219] 2-7-1. Main Program

[0220] The control circuit 51 repeatedly executes its operation. Figure 9 The main program shown.

[0221] like Figure 9 As shown, the control circuit 51 first waits in S110 until a preset time base is reached (S110: NO). When the time base is reached (S110: YES), the control circuit 51 sequentially transitions from S120 to S170.

[0222] In S120, the control circuit 51 performs A-D conversion processing. In the A-D conversion processing, the control circuit 51 converts the battery voltage signal and the current measurement signal into their respective digital values ​​and stores the respective digital values ​​in RAM.

[0223] In S130, the control circuit 51 performs a switch determination process. In the switch determination process, the control circuit 51 stores the logic (positive or negative, or HIGH or LOW, or 1 or 0) of the voltages received from the main power switch 36, the mode selection switch 37, the contactor switch 20, the first Hall element 34a, the second Hall element 34b, and the second latch circuit 58 in RAM.

[0224] In S140, the control circuit 51 performs a standby determination process. In the standby determination process, the control circuit 51 determines whether to transfer the reciprocating motion tool 1 to the standby state.

[0225] In S150, the control circuit 51 performs a defect condition determination process. During this process, the control circuit 51 determines whether an error flag is set. The error flag is (i) set when a defect occurs, and (ii) cleared when no defect occurs. If an error flag is set, the control circuit 51 performs a pre-determined action corresponding to the defect.

[0226] In S160, control circuit 51 performs motor control processing. Details of the motor control processing will be described later.

[0227] In S170, the control circuit 51 performs display processing. During display processing, the control circuit 51 illuminates either the first display 38 or the second display 39 corresponding to the set operating mode. More specifically, when the reciprocating motion tool 1 is set to single-fire mode, the control circuit 51 outputs a first illumination signal to the first display 38. When the reciprocating motion tool 1 is set to continuous-fire mode, the control circuit 51 outputs a second illumination signal to the second display 39. Furthermore, when an error flag is set, the control circuit 51 outputs both the first and second illumination signals to the first display 38 and the second display 39, respectively.

[0228] 2-7-2. Interruption Handling

[0229] In addition to the main program described above, the control circuit 51 also executes an interrupt process (not shown). In this interrupt process, the control circuit 51 stores the logic (positive or negative, HIGH or LOW, 1 or 0) of the voltages of the first to third pulse signals in RAM. In this embodiment, the control circuit 51 periodically and repeatedly executes the interrupt process. In other embodiments, the control circuit 51 may execute the interrupt process based on the edges or voltage levels of the first to third pulse signals or other signals.

[0230] 2-7-3. Motor Control Processing

[0231] like Figure 10 As shown, in the motor control process, the control circuit 51 first determines in S310, based on the logic of the voltage of the contactor switch 20 stored in RAM, whether the contactor switch 20 has been turned on.

[0232] When contactor switch 20 is open (S310: NO), control circuit 51 immediately terminates motor control processing. When contactor switch 20 is closed (S310: YES), control circuit 51 proceeds to S320. In S320, control circuit 51 outputs the corresponding PWM signal to the selected high-side switch and the selected low-side switch (i.e., a combination of high-side and low-side switches that impairs the rotation of rotor 26). The corresponding PWM signal has the initial duty cycle described above.

[0233] In the following S330, the control circuit 51 determines whether a first predetermined time (e.g., 5 seconds) has elapsed since the start of outputting the corresponding PWM signal. This first predetermined time is set to prevent the nail from being accidentally ejected if the pressing member 6 is held in a state where it is pressed against an object against the user's will. If the first predetermined time has elapsed (S330: YES), the control circuit 51 proceeds to S340, stops the output of the corresponding PWM signal, and ends the motor control process.

[0234] If the first predetermined time has not elapsed (S330: NO), the control circuit 51 proceeds to S350, and based on the logic of the output of the second latch circuit 58 stored in RAM, determines whether the trigger switch 21 has been turned on. If the trigger switch 21 is turned off (S350: NO), the control circuit 51 immediately terminates the motor control process.

[0235] With trigger switch 21 already turned on (S350: YES), control circuit 51 proceeds to S360 to determine whether the reciprocating motion tool 1 is set to continuous firing mode. More specifically, control circuit 51 determines whether a continuous firing mode flag is set. When control circuit 51 is activated, the continuous firing mode flag is cleared. In reciprocating motion tool 1, whenever the user presses mode selection switch 37, the operating mode of reciprocating motion tool 1 is switched between single-fire mode and continuous firing mode. Therefore, control circuit 51 sets or clears the continuous firing mode flag based on the logic of the voltage of mode selection switch 37 stored in RAM.

[0236] With the reciprocating tool 1 set to continuous firing mode (S360: YES), the control circuit 51 proceeds to S370 and sets the drive permission flag. The drive permission flag indicates that the drive of the nail is permitted. In the following S380, the control circuit 51 outputs a switch-on signal to the 7th switch Q7, turning on the 7th switch Q7, and proceeds to S410.

[0237] When the reciprocating motion tool 1 is set to single-shot mode (S360: NO), the control circuit 51 proceeds to S390 to determine whether a second predetermined time (e.g., 50 milliseconds) has elapsed. This second predetermined time is set to prevent the reciprocating motion tool 1 from driving in a nail when an operation prohibited in single-shot mode, where the pressing component 6 is pressed against the workpiece while the trigger 9 is pulled, is performed. If the second predetermined time has elapsed (S390: YES), the control circuit 51 proceeds to S370.

[0238] If the second specified time has not elapsed (S390: NO), the control circuit 51 switches to S400 and clears the input permission flag.

[0239] In the following S410, the control circuit 51 performs drive processing.

[0240] In the drive process, the control circuit 51 performs the soft start described above when the enable flag is set. When the soft start is complete, the control circuit 51 sets the duty cycle of the PWM signal output to the selected high-side switch and the selected low-side switch (that is, the high-side switch and the low-side switch that help rotate the rotor 26) to 100%.

[0241] If the input permission flag is cleared, the control circuit 51 immediately terminates the drive process.

[0242] In the following S420, the control circuit 51 performs a stop process.

[0243] During the stop process, the control circuit 51 clears the motor stop flag. The motor stop flag indicates that the electric motor 24 has stopped. Next, based on the logic of the voltage of the first Hall element 34a stored in RAM, the control circuit 51 determines whether the reciprocating component 18 is in the stop preparation position. If the reciprocating component 18 is in the stop preparation position, the control circuit 51 calculates the remaining drive time of the electric motor 24. When the calculated remaining drive time has elapsed, the control circuit 51 sets the duty cycle of all PWM signals from the first to the sixth to 0%, causing the electric motor 24 to transition to a free-running state.

[0244] Next, the control circuit 51 determines, based on the logic of the voltage of the second Hall element 34b stored in RAM, whether the reciprocating component 18 is in the waiting position. If the reciprocating component 18 is in the waiting position, the control circuit 51 outputs a PWM signal with a predetermined duty cycle (e.g., 100%) to at least two of the fourth to sixth switches Q4 to Q6 to cause the electric motor 24 to short-circuit brake.

[0245] Next, the control circuit 51 determines, based on the logic of the voltages of the first to third pulse signals stored in RAM so far, whether the electric motor 24 has stopped. If the electric motor 24 has stopped, the control circuit 51 sets a motor stop flag.

[0246] When this stop process is completed, control circuit 51 switches to S430 to determine whether the electric motor 24 has stopped. More specifically, control circuit 51 determines whether a motor stop flag is set.

[0247] If the electric motor 24 has not stopped (i.e., the motor stop sign has been cleared) (S430: NO), the control circuit 51 proceeds to S440. In S440, the control circuit 51 outputs a switch-on signal to the 7th switch Q7, thereby turning on the 7th switch Q7. In other words, the control circuit 51 continuously outputs a switch-on signal to the 7th switch Q7, thereby keeping the 7th switch Q7 in its on state.

[0248] When the electric motor 24 has stopped (i.e., the motor stop sign is set) (S430: YES), the control circuit 51 proceeds to S450. In S450, the control circuit 51 outputs a switch-off signal to the 7th switch Q7, thereby disconnecting the 7th switch Q7.

[0249] 2-8. Technical Effects of the Implementation Method

[0250] According to the reciprocating motion tool 1 configured as described above, when the reciprocating component 18 reaches the waiting position during one reciprocating motion, the first to third AND gates 56a to 56c of the first signal cutoff circuit 56 cut off the first to third PWM signals to the drive circuit 55 without delay. As a result, the drive of the electric motor 24 based on the drive circuit 55 can stop immediately.

[0251] Therefore, the delay in stopping the electric motor 24 can be suppressed according to the reciprocating motion tool 1.

[0252] Furthermore, in the reciprocating motion tool 1, when the reciprocating component 18 reaches the waiting position during one reciprocating motion, the 4th to 6th PWM signals that brake the electric motor 24 are output from the control circuit 51 to the drive circuit 55. As a result, the electric motor 24 can stop immediately.

[0253] Furthermore, according to the reciprocating motion tool 1, by having the user press the crimping member 6 onto the workpiece, the first signal cutoff circuit 56 is disabled, thereby enabling the electric motor 24 to be driven.

[0254] Furthermore, the reciprocating motion tool 1 is configured to detect the position of the reciprocating component 18 using a magnetic field. Therefore, compared to a reciprocating motion tool 1 configured to detect the position of the reciprocating component 18 mechanically, the reciprocating motion tool 1 exhibits superior durability. Moreover, compared to a reciprocating motion tool 1 configured to detect the position of the reciprocating component 18 optically, this type of reciprocating motion tool 1 is less susceptible to dust interference during the position detection of the reciprocating component 18.

[0255] Furthermore, according to the reciprocating motion tool 1, since the first Hall element 34a and the second Hall element 34b are arranged on the radially outer side of the support 31, the size of the reciprocating motion tool 1 in the direction that intersects the support 31 radially can be reduced.

[0256] Furthermore, according to the reciprocating motion tool 1, since the support 31 is a non-magnetic body, the first Hall element 34a or the second Hall element 34b can easily detect the S pole of the first magnet 32 ​​or the N pole of the second magnet 33.

[0257] 2-9. Correspondence of terms

[0258] In this embodiment, the upper dead point of the reciprocating component 18 corresponds to an example of the first dead point in the summary of the embodiment, and the lower dead point of the reciprocating component 18 corresponds to an example of the second dead point in the summary of the embodiment. The first to third PWM signals each correspond to an example of at least one drive signal in the summary of the embodiment. The combination of the second magnet 33 and the second Hall element 34b corresponds to an example of the position detector in the summary of the embodiment, and the second position detection signal corresponds to an example of the position detection signal in the summary of the embodiment. The N pole of the second magnet 33 corresponds to an example of the first magnetic pole in the summary of the embodiment, and the S pole of the second magnet 33 corresponds to an example of the second magnetic pole in the summary of the embodiment. The first signal cutoff circuit 56 corresponds to an example of the signal cutoff circuit in the summary of the embodiment, and the combination of the first to third AND gates 56a to 56c corresponds to an example of the wiring logic in the summary of the embodiment. The contactor switch 20 corresponds to an example of the manual switch in the summary of the embodiment, and the first latch circuit 54 corresponds to an example of the latch circuit in the summary of the embodiment.

[0259] 2-10. Variations

[0260] This invention is not limited to the above-described embodiments and can be implemented in various modifications.

[0261] 2-10-1. First Variation Example

[0262] The reciprocating motion tool 1 of this first modification corresponds to the reciprocating motion tool 1 of the above-described embodiment with partial modifications.

[0263] Therefore, the parts that are common to the above embodiments will be given the same reference numerals, and their descriptions will be omitted. Only the differences between the above embodiments will be described.

[0264] 2-10-1-1. Differences in mechanical structure

[0265] First, in the reciprocating motion tool 1 of this first modification, the bracket 31, the first magnet 32, the second magnet 33, the Hall IC 34, and the first latch circuit 54 in the above embodiment are removed.

[0266] like Figure 11A as well as Figure 11B As shown, the reciprocating motion tool 1 in this first modification has a replacement support 60 at the center of the cam 28 (that is, the center of rotation of the cam 28).

[0267] The alternative support 60 is a non-magnetic body. The alternative support 60 is configured to rotate integrally with the cam 28. A third magnet 61 is provided on the upper surface of the alternative support 60. The third magnet 61 is disposed at the center of the alternative support 60, and further at the center of the cam 28. In other words, the third magnet 61 is disposed on the upper surface of the alternative support 60 with its N pole and S pole facing radially outward from the alternative support 60.

[0268] In this first modification, the reciprocating motion tool 1 has a replacement Hall IC 62 above the third magnet 61. The replacement Hall IC 62 has a third Hall element 62a. Figure 11C As shown, the third Hall element 62a is configured such that its output voltage continuously increases as the rotation angle of the third magnet 61 (and consequently, the rotation angle of the cam 28) increases. In this first modification, the third Hall element 62a is configured to: (i) output a voltage of 0 volts when the third magnet 61 is at a rotation angle of 0° (or 360°), and (ii) output a maximum voltage when the third magnet 61 is at a rotation angle immediately before reaching 360°. In this first modification, the third magnet 61 is arranged on the alternative support 60 such that (i) the top dead center of the reciprocating member 18 corresponds to a rotation angle of 0°, and (ii) the waiting position of the reciprocating member 18 corresponds to a rotation angle immediately before reaching 360°.

[0269] 2-10-1-2. Differences in electrical configuration

[0270] like Figure 12 As shown, the reciprocating motion tool 1 of this first modification includes a third latching circuit 63, replacing the first latching circuit 54 in the above embodiment. The third latching circuit 63 is connected to: (i) a third Hall element 62a and (ii) a contactor switch 20. The third Hall element 62a is also connected to the control circuit 51.

[0271] like Figure 13A As shown, the third latch circuit 63, in addition to having the single pulse generation circuit 54a, reset circuit 54b, and holding circuit 54c in the above embodiments, also has a voltage comparison circuit 63a in its input section, which is different from the first latch circuit 54.

[0272] Voltage comparison circuit 63a is connected to the third Hall element 62a. Voltage comparison circuit 63a is configured to compare the output voltage of the third Hall element 62a with a specified voltage. In this first modification, the specified voltage is set to be the same as the output voltage of the third Hall element 62a when the reciprocating component 18 reaches the waiting position.

[0273] like Figure 13B As shown, the voltage comparison circuit 63a is configured such that: (i) its output is set to positive (or HIGH) until the output voltage of the third Hall element 62a reaches the specified voltage; and (ii) its output is set to negative (or LOW) when the output voltage of the third Hall element 62a reaches the specified voltage.

[0274] In this first variation, the outputs of the single pulse generating circuit 54a and the voltage comparator circuit 63a are switched from positive to negative (that is, corresponding to the falling edge of the output of the voltage comparator circuit 63a) to generate and output a single pulse.

[0275] 2-10-1-3. Differences in treatment

[0276] In the main program of this first variation, the control circuit 51 is configured such that, in the A-D conversion process of S120, the output voltage of the third Hall element 62a is converted into a digital value and the digital value is stored in RAM. In the switch determination process of S130, the control circuit 51 does not store the logic of the voltages of the first Hall element 34a and the second Hall element 34b in RAM.

[0277] In the motor control process of this first variation, during the stop process in S420, the control circuit 51 determines, based on the digital value of the output voltage of the third Hall element 62a stored in RAM, whether the reciprocating component 18 is in a stop preparation position or a waiting position.

[0278] 2-10-1-4. Technical Effects in the First Variation

[0279] The reciprocating motion tool 1 in the first modified example constructed as described above can achieve the same effect as the reciprocating motion tool 1 in the above embodiment.

[0280] 2-10-2. Other variations

[0281] In a certain variation, the first signal cutoff circuit 56, the second signal cutoff circuit 59, the first latch circuit 54, the second latch circuit 58, and / or the third latch circuit 63 may include a PLD (such as an FPGA).

[0282] In a certain variation, the waiting position of the reciprocating component 18 may be different from the position that causes the reciprocating component 18 to stop.

[0283] 2-11. Supplement

[0284] Furthermore, multiple functions performed by one component in the above embodiments can be performed by multiple components, and one function performed by one component can be performed by multiple components. Additionally, multiple functions performed by multiple components can be performed by one component, and one function performed by multiple components can be performed by one component. Furthermore, a portion of the configuration in the above embodiments can be omitted. Furthermore, at least a portion of the configuration in one of the above embodiments can be added to, or substituted for, the configuration in another of the above embodiments.

Claims

1. A reciprocating motion tool, characterized in that, The reciprocating motion tool has the following features: The reciprocating component is configured to reciprocate between the first dead point and the second dead point; An electric motor is configured to generate driving force; A transmission device configured to transmit the driving force of the electric motor to the reciprocating component at least during the stroke of the reciprocating component from the second dead point to the first dead point; A control circuit configured to output at least one drive signal for driving the electric motor; A drive circuit configured to (i) receive the at least one drive signal and (ii) drive the electric motor according to the received at least one drive signal; A position detector is configured to output a position detection signal whenever the reciprocating component reaches a predetermined position during at least one reciprocating motion; as well as The signal cutting-off circuit has wiring logic configured to cut off at least one drive signal to the drive circuit in accordance with the position detection signal output by the position detector.

2. The reciprocating motion tool according to claim 1, characterized in that, The signal interruption circuit is configured to: (i) receive a first logic value and be invalidated, and (ii) receive a second logic value and be validated. The second logic value is the opposite of the first logic value.

3. The reciprocating motion tool according to claim 2, characterized in that, The reciprocating motion tool also has: A manual switch, configured to be manually operated by the user of the reciprocating motion tool; and The latching circuit is configured to continuously output the second logic value to the signal cutoff circuit in accordance with the position detection signal output by the position detector until the manual switch is manually operated.

4. The reciprocating motion tool according to claim 3, characterized in that, The reciprocating tool also includes a pressing component, which is configured to be pressed onto the workpiece by the user. The manual switch is configured to be pressed onto the workpiece by the pressing component and thus manually operated.

5. The reciprocating motion tool according to any one of claims 1 to 4, characterized in that, The position detector comprises: (i) a magnet having a first magnetic pole and a second magnetic pole; and (ii) a Hall element configured to detect the first magnetic pole of the magnet. The position detector is configured such that, corresponding to the reciprocating component reaching the predetermined position, the Hall element detects the first magnetic pole and outputs the position detection signal.

6. The reciprocating motion tool according to claim 5, characterized in that, The transfer device includes: A cam, which (i) has an outer periphery having a plurality of pins arranged circumferentially on the cam, and (ii) is configured to rotate by the driving force of the electric motor; and A support that (i) holds the magnet and (ii) is configured to rotate together with the cam. The reciprocating component (i) extends between the first stop and the second stop, (ii) has a plurality of racks in its extending direction, and (iii) is configured to be driven from the second stop toward the first stop by engaging the plurality of racks with the plurality of pins respectively.

7. The reciprocating motion tool according to claim 6, characterized in that, The first magnetic pole is directed toward the radially outer side of the support.

8. The reciprocating motion tool according to claim 6 or 7, characterized in that, The cam and the bracket are configured to rotate around the same axis.

9. The reciprocating motion tool according to claim 8, characterized in that, The electric motor includes a rotor that acts as the same shaft.

10. The reciprocating motion tool according to any one of claims 6 to 9, characterized in that, The support is a non-magnetic material.

11. The reciprocating motion tool according to any one of claims 1 to 10, characterized in that, The at least one driving signal is at least one pulse width modulation signal.

12. The reciprocating motion tool according to claim 11, characterized in that, The electric motor is a brushless DC motor equipped with coils 1 to 3. The driving circuit includes: (i) at least a portion forming a full-bridge circuit, and (ii) first to sixth semiconductor switches connected to the first to third coils. The first to third semiconductor switches are the high-side switches in the full-bridge circuit. The fourth to sixth semiconductor switches are the low-side switches in the full-bridge circuit. The at least one pulse width modulation signal includes: the first to third pulse width modulation signals corresponding to the first to third semiconductor switches, respectively. The wiring logic is configured such that, corresponding to the position detection signal output by the position detector, the first to third pulse width modulation signals are cut off for the driving circuit.

13. The reciprocating motion tool according to claim 12, characterized in that, The control circuit is configured to output, corresponding to the position detection signal output by the position detector, the 4th to 6th pulse width modulation signals that cause the electric motor to brake to the drive circuit. The 4th to 6th pulse width modulation signals correspond to the 4th to 6th semiconductor switches, respectively.

14. The reciprocating motion tool according to claim 13, characterized in that, The control circuit includes a microcomputer configured to output the first to sixth pulse width modulation signals.

15. The reciprocating motion tool according to any one of claims 1 to 14, characterized in that, The specified position corresponds to: (i) a stopping position that stops the reciprocating component, and / or (ii) a waiting position that allows the reciprocating component to wait for at least one next reciprocating action.

16. The reciprocating motion tool according to any one of claims 1 to 15, characterized in that, The reciprocating motion tool has the following features: A cylinder containing compressed gas; and A piston, which (i) is located inside the cylinder, and (ii) exerts force on the reciprocating component at the second dead center by the compressed gas. The reciprocating component is configured to be driven from the first dead point to the second dead point by the piston.

17. The reciprocating motion tool according to claim 16, characterized in that, The reciprocating component is configured such that: (i) it is located at the first dead center, corresponding to the piston being located at its top dead center; and (ii) it is located at the second dead center, corresponding to the piston being located at its bottom dead center.

18. A method for controlling an electric motor of a reciprocating tool, characterized in that, The method comprises the following steps: At least one drive signal for driving the electric motor is output to the drive circuit of the reciprocating motion tool, wherein the drive circuit is configured to drive the electric motor according to the at least one drive signal. The driving force of the electric motor is transmitted to the reciprocating component of the reciprocating motion tool, wherein the reciprocating component is configured to reciprocate between a first dead point and a second dead point, transmitting the driving force at least from the second dead point to the first dead point; and The drive of the electric motor is stopped by using wiring logic, wherein the wiring logic is configured to cut off the at least one drive signal to the drive circuit corresponding to the reciprocating component having reached a predetermined position in at least one reciprocating motion.

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