JP7352793B2 - impact tools - Google Patents

Description

BACKGROUND OF THE INVENTION This disclosure relates generally to impact tools, and more particularly to impact tools that include electric motors.

The impact rotary tool described in Patent Document 1 includes an impact mechanism, an impact detection section, a control section, and a voltage detection section. The impact mechanism has a hammer and applies a striking impact to the output shaft using the motor output. The impact detection section detects an impact caused by the impact mechanism. The control section stops rotation of the motor based on the detection result of the impact detection section. The voltage detection section detects the voltage of the impact detection section. The control section determines whether or not the impact detection section is abnormal based on the voltage detected by the voltage detection section when the motor is not rotating.

JP 2017-132021 Publication

The impact rotary tool (impact tool) described in Patent Document 1 can determine whether or not the impact detection section is abnormal, but it is difficult to determine whether the impact detection section is abnormal or not. It was not possible to determine the type of behavior of the impact mechanism inside.

The present disclosure aims to provide an impact tool capable of determining the type of behavior of an impact mechanism during a striking operation.

An impact tool according to one aspect of the present disclosure includes an electric motor, an impact mechanism, an acquisition section, a determination section, and a counter . The impact mechanism receives power from the electric motor to perform a striking operation that generates striking force. The acquisition unit acquires a value of torque current supplied to the electric motor. The discrimination unit performs a primary discrimination process based on a torque current acquired value that is a value of the torque current acquired by the acquisition unit , and a secondary discrimination process based on a result of the primary discrimination process. A type of behavior of the impact mechanism during a striking action is determined. The counter counts the number of times the striking force is generated. In the primary discrimination process, the discrimination unit discriminates a plurality of types of behavior including a plurality of types of abnormalities of the impact mechanism during the striking operation based on the torque current acquired value. The counter counts, for each of the plurality of types of behavior, the number of times the impact force is generated in a state where the behavior of the impact mechanism determined in the primary determination process of the determination unit is the behavior. In the secondary discrimination process, the discrimination unit determines that the behavior counted by the counter the most times among the plurality of types of behaviors is the behavior type of the impact mechanism during the hitting motion. do.

The present disclosure has the advantage that it is possible to determine the type of behavior of the impact mechanism during a striking action.

FIG. 1 is a block diagram of an impact tool according to one embodiment. FIG. 2 is a perspective view of the same impact tool. FIG. 3 is a side sectional view of the same impact tool. FIG. 4 is a perspective view of essential parts of the impact tool same as above. FIG. 5 is a side view of the drive shaft and two steel balls of the same impact tool. FIG. 6 is a top view of the drive shaft and two steel balls of the same impact tool. FIGS. 7A to 7C are diagrams illustrating the proper impact operation of the above impact tool. FIGS. 8A to 8D are diagrams illustrating the double-strike operation of the same impact tool. 9A to 9D are diagrams illustrating the V-bottoming operation of the same impact tool as above.

Hereinafter, an impact tool 1 according to an embodiment will be explained using the drawings. However, each embodiment described below is only a part of various embodiments of the present disclosure. Each of the embodiments described below can be modified in various ways depending on the design, etc., as long as the objective of the present disclosure can be achieved. Furthermore, each of the drawings described in each of the embodiments below is a schematic drawing, and the ratio of the size and thickness of each component in the drawing does not necessarily reflect the actual size ratio. do not have.

(1) Overview As shown in FIG. 1, the impact tool 1 of this embodiment includes an electric motor 3 (AC motor), an impact mechanism 40, an acquisition section 90, and a determination section 84. The impact mechanism 40 receives power from the electric motor 3 and performs a striking operation that generates striking force. The acquisition unit 90 acquires the value of the torque current supplied to the electric motor 3. The determining unit 84 determines the type of behavior of the impact mechanism 40 during a striking action based on the torque current acquired value, which is the value of the torque current acquired by the acquiring unit 90.

"Distinguishing the type of behavior of the impact mechanism 40" refers to distinguishing the type of behavior of the actual impact mechanism 40 from other types. For example, determining that the type of behavior is a "proper hit" which is an appropriate behavior corresponds to distinguishing the type of behavior of the impact mechanism 40 from behaviors other than "proper hit." That is, determining that the type of behavior is "appropriate batting" corresponds to determining the type of behavior.

In this manner, in the impact tool 1, by using the acquired torque current value, it is possible to determine the type of behavior of the impact mechanism 40 during the impact operation.

The impact mechanism 40 of this embodiment includes a hammer 42 and an anvil 45. Specifically, the impact force generated by the impact mechanism 40 is an impact force generated when the hammer 42 collides with the anvil 45. The types of behavior of the impact mechanism 40 during a striking operation include, for example, the contact (collision) position between the hammer 42 and the anvil 45, and the time when the hammer 42 separates from the anvil 45 after the hammer 42 collides with the anvil 45. It is classified according to the amount of movement of 42, etc.

(2) Configuration The configuration of the impact tool 1 will first be described in more detail with reference to FIGS. 2 to 4. In the following description, the direction in which the drive shaft 41 and the output shaft 61 (described later) are lined up is defined as the front-rear direction, and the output shaft 61 side seen from the drive shaft 41 is defined as the front, and the drive shaft 41 seen from the output shaft 61 is side behind. In addition, in the following description, the direction in which the body part 21 and the grip part 22, which will be described later, are lined up is defined as the vertical direction. The part 22 side is facing down.

The impact tool 1 of this embodiment includes an electric motor 3, a transmission mechanism 4, an output shaft 61 (socket attachment part), a housing 2, a trigger volume 23, a control part 7 (see FIGS. 1 and 3), It is equipped with

The housing 2 houses the electric motor 3, the transmission mechanism 4, the control section 7, and a part of the output shaft 61. The housing 2 has a body part 21 and a grip part 22. The shape of the body portion 21 is cylindrical. The grip portion 22 protrudes from the body portion 21.

The trigger volume 23 protrudes from the grip portion 22. The trigger volume 23 is an operation unit that receives an operation for controlling the rotation of the electric motor 3. By pulling the trigger volume 23, the electric motor 3 can be turned on and off. Further, the rotational speed of the electric motor 3 can be adjusted by the amount of pulling of the trigger volume 23. The larger the retraction amount is, the faster the rotational speed of the electric motor 3 becomes. The control unit 7 (see FIG. 1) rotates or stops the electric motor 3 according to the amount of pull of the trigger volume 23, and also controls the rotational speed of the electric motor 3. In the impact tool 1 of this embodiment, a socket 62 as a tip tool is attached to the output shaft 61. The output shaft 61 receives the rotational force of the electric motor 3 and rotates together with the socket 62. The rotation speed of the electric motor 3 is controlled by operating the trigger volume 23, thereby controlling the rotation speed of the socket 62.

A rechargeable battery pack is detachably attached to the impact tool 1. The impact tool 1 operates using a battery pack as a power source. That is, the battery pack is a power source that supplies current to drive the electric motor 3. The battery pack is not a component of the impact tool 1. However, the impact tool 1 may include a battery pack. The battery pack includes a battery assembly configured by connecting a plurality of secondary batteries (for example, lithium ion batteries) in series, and a case housing the battery assembly.

The electric motor 3 is, for example, a brushless motor. In particular, the electric motor 3 of this embodiment is a synchronous motor, more specifically a permanent magnet synchronous motor (PMSM). The electric motor 3 includes a rotor 31 having a rotating shaft 311 and a permanent magnet 312, and a stator 32 having a coil 321. The electromagnetic interaction between the permanent magnets 312 and the coils 321 causes the rotor 31 to rotate relative to the stator 32 .

A socket 62 as a tip tool is attached to the output shaft 61. The transmission mechanism 4 transmits the rotation of the rotating shaft 311 of the electric motor 3 to the socket 62 via the output shaft 61. This causes the socket 62 to rotate. By rotating the socket 62 while the socket 62 is applied to a fastening member (bolt, screw (wood screw, etc.), nut, etc.), it becomes possible to tighten or loosen the fastening member. The transmission mechanism 4 includes an impact mechanism 40. The impact tool 1 of this embodiment is an electric impact driver that tightens screws while performing a striking action using an impact mechanism 40. In the striking operation, a striking force is applied to a fastening member such as a screw through the output shaft 61.

Note that the socket 62 can be attached to and detached from the output shaft 61. A socket anvil can be attached to the output shaft 61 instead of the socket 62. A bit (for example, a driver bit or a drill bit) as a tip tool can be attached to the output shaft 61 via a socket anvil.

In this way, the output shaft 61 is configured to hold a tip tool (socket 62 or bit). In this embodiment, the tip tool is not included in the configuration of the impact tool 1. However, the tip tool may be included in the configuration of the impact tool 1.

The transmission mechanism 4 includes a planetary gear mechanism 48 in addition to the impact mechanism 40. The impact mechanism 40 includes a drive shaft 41, a hammer 42, a return spring 43, an anvil 45, and two steel balls 49. Rotation of the rotating shaft 311 of the electric motor 3 is transmitted to the drive shaft 41 via the planetary gear mechanism 48 . The drive shaft 41 is arranged between the electric motor 3 and the output shaft 61.

The hammer 42 moves relative to the anvil 45, receives power from the electric motor 3, and applies a rotational blow to the anvil 45. Hammer 42 includes a hammer body 420 and two protrusions 425. The two protrusions 425 protrude from the surface of the hammer body 420 on the output shaft 61 side. The hammer body 420 has a through hole 421 through which the drive shaft 41 is passed. Further, the hammer body 420 has two grooves 423 on the inner peripheral surface of the through hole 421. The drive shaft 41 has two grooves 413 (see FIG. 5) on its outer peripheral surface. The two groove portions 413 are connected. Two steel balls 49 are sandwiched between the two grooves 423 and the two grooves 413. The two grooves 423, the two grooves 413, and the two steel balls 49 constitute a cam mechanism. While the two steel balls 49 are moving, the hammer 42 is movable in the axial direction of the drive shaft 41 and rotatable with respect to the drive shaft 41. As the hammer 42 moves toward or away from the output shaft 61 along the axial direction of the drive shaft 41, the hammer 42 rotates with respect to the drive shaft 41.

The anvil 45 is formed integrally with the output shaft 61. The anvil 45 holds a tip tool (socket 62 or bit) via an output shaft 61. Anvil 45 includes an anvil body 450 and two claws 455. The shape of the anvil body 450 is annular. The two claw portions 455 protrude from the anvil body 450 in the radial direction of the anvil body 450. The anvil 45 faces the hammer body 420 in the axial direction of the drive shaft 41. Further, when the impact mechanism 40 is not performing a striking operation, the two protrusions 425 of the hammer 42 and the two claws 455 of the anvil 45 are in contact with each other in the rotational direction of the drive shaft 41, and the hammer 42 and the anvil 45 are in contact with each other. rotates as one. Therefore, at this time, the drive shaft 41, the hammer 42, the anvil 45, and the output shaft 61 rotate together.

The return spring 43 is sandwiched between the hammer 42 and the planetary gear mechanism 48. The return spring 43 of this embodiment is a conical coil spring. The impact mechanism 40 further includes a plurality of (two in FIG. 3) steel balls 50 and a ring 51 sandwiched between the hammer 42 and the return spring 43. Thereby, the hammer 42 is rotatable relative to the return spring 43. The hammer 42 receives a force directed toward the output shaft 61 from the return spring 43 in the axial direction of the drive shaft 41 .

Hereinafter, the movement of the hammer 42 toward the output shaft 61 in the axial direction of the drive shaft 41 will be referred to as "the hammer 42 moving forward." Furthermore, hereinafter, the movement of the hammer 42 in the axial direction of the drive shaft 41 in a direction away from the output shaft 61 will be referred to as "the hammer 42 moving backward."

In the impact mechanism 40, when the load torque exceeds a predetermined value, a striking operation is started. That is, as the load torque increases, the component of the force generated between the hammer 42 and the anvil 45 in the direction of retracting the hammer 42 also increases. When the load torque exceeds a predetermined value, the hammer 42 moves backward while compressing the return spring 43. Then, as the hammer 42 moves backward, the two protrusions 425 of the hammer 42 get over the two claws 455 of the anvil 45, and the hammer 42 rotates. Thereafter, the hammer 42 receives the return force from the return spring 43 and moves forward. Then, when the drive shaft 41 rotates approximately half a rotation, the two protrusions 425 of the hammer 42 collide with the side surfaces 4550 of the two claws 455 of the anvil 45. In the impact mechanism 40, the two protrusions 425 of the hammer 42 collide with the two claws 455 of the anvil 45 every time the drive shaft 41 rotates approximately half a rotation. That is, the hammer 42 applies a rotational impact to the anvil 45 every time the drive shaft 41 rotates approximately half a rotation.

In this manner, in the impact mechanism 40, collisions between the hammer 42 and the anvil 45 repeatedly occur. Due to the torque generated by this collision, fastening members such as bolts, screws, or nuts can be tightened more strongly than in the case where there is no collision.

Here, as shown in FIG. 6, the two groove portions 413 (see FIG. 5) of the drive shaft 41 are each formed in a V-shape when viewed from the vertical direction. When the steel ball 49 is located at a position corresponding to the center of the V-shape (the state shown by the solid line in FIGS. 5 and 6), the hammer 42 has moved forward to the front end of its movable range. When the impact mechanism 40 is not performing a striking operation, the steel ball 49 remains at a position corresponding to the center of the V-shape. When the steel ball 49 is located at a position corresponding to any one of both ends of the V-shape (the state shown by the two-dot chain line in FIGS. 5 and 6), the hammer 42 retreats to the rear end of its movable range. are doing. In this specification, the retraction of the hammer 42 to the rear end within its movable range is referred to as "maximum retraction." That is, in this specification, the movement of the hammer 42 to the farthest position from the anvil 45 within the movable range of the hammer 42 is referred to as "maximum retreat." The maximum retraction of the hammer 42 occurs when the impact mechanism 40 is performing a striking operation, for example, when the rotation speed of the electric motor 3 is relatively high, or when the magnitude of the load applied to the output shaft 61 of the impact tool 1 This may occur when there is a sudden increase in Further, the maximum retraction of the hammer 42 may occur when the spring force of the return spring 43 that advances the hammer 42 is insufficient. The maximum retraction of the hammer 42 may also occur if the rotational speed of the electric motor 3 is not appropriately adjusted depending on the type, shape, rigidity, etc. of the tip tool.

Further, contrary to the maximum retreat, the distance that the hammer 42 retreats may be insufficient. In this case, the behavior of the hammer 42 may become unstable compared to the case where the distance the hammer 42 retreats is appropriate. The determining unit 84 detects a situation in which the distance of the hammer 42 to retreat is insufficient as one type of behavior of the impact mechanism 40 during a striking operation.

Details of how the determining unit 84 detects (determines) the type of behavior of the impact mechanism 40 during a striking operation will be described in the section "(4) Operation example".

(3) Control unit The control unit 7 includes a computer system having one or more processors and memory. At least some of the functions of the control unit 7 are realized by the processor of the computer system executing a program recorded in the memory of the computer system. The program may be recorded in a memory, provided through a telecommunications line such as the Internet, or provided recorded on a non-temporary recording medium such as a memory card.

As shown in FIG. 1, the control unit 7 includes a command value generation unit 71, a speed control unit 72, a current control unit 73, a first coordinate converter 74, a second coordinate converter 75, and a magnetic flux It has a control section 76, an estimation section 77, an out-of-step detection section 78, a discrimination section 84, an output section 85, and a counter 86. The impact tool 1 also includes a control section 7, an inverter circuit section 81, a motor rotation measurement section 82, and a plurality of (two in FIG. 1) current sensors 91 and 92.

The control unit 7 controls the operation of the electric motor 3. More specifically, the control unit 7 is used together with an inverter circuit unit 81 that supplies current to the electric motor 3, and controls the operation of the electric motor 3 through feedback control. The control unit 7 performs vector control to independently control the excitation current (d-axis current) and torque current (q-axis current) supplied to the electric motor 3.

Further, the control unit 7 controls the operation of the electric motor 3 based on the determination result of the determination unit 84. For example, the control unit 7 increases or decreases the rotation speed of the electric motor 3 depending on the type of behavior of the impact mechanism 40 during a striking operation, which is determined by the determination unit 84. The determination unit 84 of this embodiment is included in the control unit 7. However, the determination unit 84 does not need to be included in the control unit 7.

Two current sensors 91 and 92 are included in the above-mentioned acquisition section 90. The acquisition unit 90 includes two current sensors 91 and 92 and a second coordinate converter 75. The acquisition unit 90 acquires the excitation current (current measurement value id1 of the d-axis current) and torque current (current measurement value iq1 of the q-axis current) supplied to the electric motor 3. The acquisition unit 90 acquires the current measurement values id1 and iq1 by calculating the current measurement values id1 and iq1 by the acquisition unit 90 itself. That is, the two-phase currents measured by the two current sensors 91 and 92 are converted by the second coordinate converter 75, thereby obtaining current measurement values id1 and iq1.

Each of the plurality of current sensors 91 and 92 includes, for example, a Hall element current sensor or a shunt resistance element. The plurality of current sensors 91 and 92 measure the current supplied from the battery pack to the motor 3 via the inverter circuit section 81. Here, three-phase currents (U-phase current, V-phase current, and W-phase current) are supplied to the electric motor 3, and the plurality of current sensors 91 and 92 measure at least two-phase currents. In FIG. 1, a current sensor 91 measures a U-phase current and outputs a current measurement value i _u 1, and a current sensor 92 measures a V-phase current and outputs a current measurement value i _v 1.

The motor rotation measurement unit 82 measures the rotation angle of the electric motor 3. As the motor rotation measuring section 82, for example, a photoelectric encoder or a magnetic encoder can be adopted.

The estimating unit 77 calculates the angular velocity ω1 of the electric motor 3 (angular velocity of the rotating shaft 311) by time-differentiating the rotation angle θ1 of the electric motor 3 measured by the motor rotation measuring unit 82.

The second coordinate converter 75 converts the current measurement values i _u 1 and i _v 1 measured by the plurality of current sensors 91 and 92 based on the rotation angle θ1 of the electric motor 3 measured by the motor rotation measurement unit 82. Coordinate transformation is performed to calculate current measurement values id1 and iq1. That is, the second coordinate converter 75 converts the current measurement values i _u 1 and i _v 1 corresponding to the three-phase current into the current measurement value id 1 corresponding to the magnetic field component (d-axis current) and the torque component (q-axis current). current) into a corresponding current measurement value iq1.

The command value generation unit 71 generates a command value cω1 of the angular velocity of the electric motor 3. The command value generation unit 71 generates, for example, a command value cω1 according to the amount of pulling of the trigger volume 23 (see FIG. 2). That is, the command value generation unit 71 increases the command value cω1 of the angular velocity as the amount of retraction increases.

The speed control unit 72 generates a command value ciq1 based on the difference between the command value cω1 generated by the command value generation unit 71 and the angular velocity ω1 calculated by the estimation unit 77. The command value ciq1 is a command value that specifies the magnitude of the torque current (q-axis current) of the electric motor 3. That is, the control unit 7 controls the operation of the electric motor 3 so that the torque current (q-axis current) supplied to the coil 321 of the electric motor 3 approaches the command value ciq1 (target value). The speed control unit 72 determines the command value ciq1 so as to reduce the difference between the command value cω1 and the angular velocity ω1.

The magnetic flux control unit 76 generates a command value cid1 based on the angular velocity ω1 calculated by the estimation unit 77 and the current measurement value iq1 (q-axis current). The command value cid1 is a command value that specifies the magnitude of the excitation current (d-axis current) of the electric motor 3. That is, the control unit 7 controls the operation of the electric motor 3 so that the excitation current (d-axis current) supplied to the coil 321 of the electric motor 3 approaches the command value cid1 (target value).

The command value cid1 generated by the magnetic flux control unit 76 is, for example, a command value for setting the magnitude of the exciting current to zero. The magnetic flux control unit 76 may generate a command value cid1 for always setting the magnitude of the excitation current to 0, or may generate a command value cid1 for making the magnitude of the excitation current larger or smaller than 0 as necessary. A value cid1 may be generated. When the excitation current command value cid1 becomes smaller than 0, a negative excitation current (weakening flux current) flows through the motor 3, and the weakening flux weakens the magnetic flux of the permanent magnet 312.

The current control unit 73 generates a command value cvd1 based on the difference between the command value cid1 generated by the magnetic flux control unit 76 and the current measurement value id1 calculated by the second coordinate converter 75. The command value cvd1 is a command value that specifies the magnitude of the excitation voltage (d-axis voltage) of the electric motor 3. The current control unit 73 determines the command value cvd1 so as to reduce the difference between the command value cid1 and the measured current value id1.

Further, the current control unit 73 generates a command value cvq1 based on the difference between the command value ciq1 generated by the speed control unit 72 and the current measurement value iq1 calculated by the second coordinate converter 75. The command value cvq1 is a command value that specifies the magnitude of the torque voltage (q-axis voltage) of the electric motor 3. The current control unit 73 generates the command value cvq1 so as to reduce the difference between the command value ciq1 and the measured current value iq1.

The first coordinate converter 74 coordinates converts the command values cvd1, cvq1 based on the rotation angle θ1 of the electric motor 3 measured by the motor rotation measurement unit 82, and converts the command values cv _u 1, cv _v 1, cv _w Calculate 1. That is, the first coordinate converter 74 converts the command value cvd1 corresponding to the magnetic field component (d-axis voltage) and the command value cvq1 corresponding to the torque component (q-axis voltage) into the command value corresponding to the three-phase voltage. Convert to cv _u 1, cv _v 1, cv _w 1. The command value cv _u 1 corresponds to the U-phase voltage, the command value cv _v 1 corresponds to the V-phase voltage, and the command value cv _w 1 corresponds to the W-phase voltage.

The inverter circuit unit 81 supplies the electric motor 3 with three-phase voltages according to the command values cv _u 1, cv _v 1, and cv _w 1. The control unit 7 controls the electric power supplied to the electric motor 3 by controlling the inverter circuit unit 81 using PWM (Pulse Width Modulation).

The electric motor 3 is driven by electric power (three-phase voltage) supplied from the inverter circuit section 81 and generates rotational power.

As a result, the control unit 7 controls the excitation current so that the excitation current (d-axis current) flowing through the coil 321 of the electric motor 3 has a magnitude corresponding to the command value cid1 generated by the magnetic flux control unit 76. Further, the control unit 7 controls the angular velocity of the electric motor 3 so that the angular velocity of the electric motor 3 corresponds to the command value cω1 generated by the command value generation unit 71.

The step-out detection section 78 detects step-out of the electric motor 3 based on the current measurement values id1 and iq1 obtained from the second coordinate converter 75 and the command values cvd1 and cvq1 obtained from the current control section 73. do. When step-out is detected, the step-out detection section 78 transmits a stop signal cs1 to the inverter circuit section 81 to stop the power supply from the inverter circuit section 81 to the electric motor 3.

The output unit 85 outputs the determination result of the determination unit 84. For example, the determination result of the determination unit 84 is stored in the memory of the control unit 7, and the output unit 85 reads the determination result of the determination unit 84 from the memory and outputs it as an electrical signal. The output unit 85 may output the determination result of the determination unit 84 to a non-temporary recording medium such as a memory card, or may output the determination result to a device external to the impact tool 1 by wired communication or wireless communication. Further, the output unit 85 may output the discrimination results of the discrimination unit 84 in real time, or may output the discrimination results during the work in a batch after the impact tool 1 finishes the work.

Further, the output section 85 has a presentation section. The presentation unit presents the discrimination result of the discrimination unit 84 using sound, light, or the like. That is, the output unit 85 presents the discrimination result of the discrimination unit 84 as sound, light, or the like. For example, the presentation section may include a light source such as a light emitting diode, and change the lighting state of the light source according to the determination result of the determination section 84. Alternatively, the presentation unit may include a speaker, a buzzer, or the like, and generate sound depending on the type of behavior of the impact mechanism 40 during the striking operation. Alternatively, the presentation unit may include a display that displays the determination result of the determination unit 84.

The counter 86 counts the number of times an impact force is generated in the impact mechanism 40. More specifically, the counter 86 counts the number of times an impact force is generated in a state where the behavior of the impact mechanism 40 determined by the determination unit 84 is a specific behavior. The specific behavior is, for example, a "proper blow" that is a proper behavior.

(4) Operation example Next, an operation example of the impact tool 1 will be described with reference to FIGS. 7A to 9D.

The determining unit 84 determines the type of behavior of the impact mechanism 40 during a striking operation based on the torque current acquired value acquired by the acquiring unit 90. In this embodiment, the acquisition unit 90 acquires the current measurement value iq1, which is the actual measurement value of the torque current, as the torque current acquisition value. The determination unit 84 uses the current measurement value iq1 as the torque current acquisition value.

Each of FIG. 7A, FIG. 8A, and FIG. 9A represents an example of the time change of the current measurement value iq1. The length of time between time points T1 and T5 on the horizontal axis in each of FIGS. 7A, 8A, and 9A is equal to the length of time required for the drive shaft 41 to rotate approximately half a rotation. The length of time required for the drive shaft 41 to rotate approximately half a rotation is, for example, approximately 20 milliseconds. Every time the drive shaft 41 rotates approximately half a rotation, the two protrusions 425 of the hammer 42 collide with the two claws 455 of the anvil 45 to apply rotational impact. At each of time points T1 and T5, the two protrusions 425 of the hammer 42 collide with the two claws 455 of the anvil 45.

That is, the impact mechanism 40 generates impact force at every predetermined impact cycle during the impact operation. The striking period in this embodiment is equal to the length of time from time T1 to time T5, and is, for example, about 20 milliseconds. The determining unit 84 determines the type of behavior of the impact mechanism 40 during the impact operation based on the acquired torque current value (current measurement value iq1) between the start point (time point T1) and the end point (time point T5) of the impact cycle. .

More specifically, the determining unit 84 divides the period corresponding to the batting cycle into a plurality of (four) periods. The determining unit 84 divides the period corresponding to the batting cycle into four equal parts, and divides the period between time T1 and time T2, the period between time T2 and time T3, and the period between time T3 and time T4 into four equal parts. , and the period between time T4 and time T5. The determining unit 84 determines the type of behavior of the impact mechanism 40 during a striking operation, based on, for example, whether the measured current value iq1 exceeds a threshold value in a certain period among these four periods. Note that time T5 in a certain hitting cycle coincides with time T1 in the next hitting cycle.

The determining unit 84 can determine the type of behavior of the impact mechanism 40 for each impact cycle. As an example, the determining unit 84 may determine the type of behavior in the Kth (K is a natural number) batting cycle after the start of the batting, or the type of behavior in the Lth (L is any natural number different from K) batting cycle. This is done independently of the determination of When the hitting cycle is repeated N (N is a natural number) cycles, the determination unit 84 can output a maximum of N determination results.

The impact period is calculated based on the rotation speed of the electric motor 3. In this embodiment, a time equal to 1/2 times the reciprocal of the rotational speed is calculated as the impact period. In this embodiment, the estimation unit 77 calculates the hitting period. The estimation unit 77 calculates the angular velocity ω1 of the electric motor 3 by differentiating the rotation angle θ1 of the electric motor 3 with respect to time. The estimation unit 77 calculates the number of rotations from the angular velocity ω1, and calculates the impact period from the number of rotations. Note that the estimation unit 77 may directly calculate the impact period from the angular velocity ω1.

7B, 7C, 8B to 8D, and 9B to 9D are diagrams schematically showing the relative positional relationship between the hammer 42 and the anvil 45. Actually, as shown in FIG. 4, each of the two protrusions 425 sequentially climbs over the two claws 455 of the anvil 45 during one rotation of the hammer 42. 7B, FIG. 7C, FIGS. 8B to 8D, and FIGS. 9B to 9D, the action of the hammer 42 rotating once is shown in FIGS. It is expressed as passing over the claw portions 455 in order. That is, in FIGS. 7B, 7C, 8B to 8D, and 9B to 9D, the area around the locus of relative rotation of the two protrusions 425 of the hammer 42 and the anvil 45 is expressed as a straight line. It is shown expanded in the form of a figure. The two-dot chain lines in FIGS. 7B, 7C, 8B to 8D, and 9B to 9D are lines that connect the two claws 455 of the anvil 45 in the rotational direction of the hammer 42, and have no substance. The arrow extending from the protrusion 425 in FIGS. 7B, 7C, 8B to 8D, and 9B to 9D is the locus of one of the two protrusions 425 of the hammer 42, and has no substance.

In the following description with reference to FIGS. 7A to 9D, unless otherwise specified, the explanation will focus on one of the two projections 425 of the hammer 42.

7A to 7C correspond to cases of "appropriate impact" in which the impact action of the impact mechanism 40 is appropriate. That is, in FIGS. 7A to 7C, the hammer 42 is not at least retracted to the maximum extent, and the distance of the retraction of the hammer 42 is appropriate. Furthermore, in FIGS. 7A to 7C, the speed at which the hammer 42 moves forward due to the spring force of the return spring 43 after the hammer 42 has retreated is appropriate. Therefore, in FIGS. 7A to 7C, the rotational speed of the hammer 42 that rotates relative to the anvil 45 as the hammer 42 moves forward is appropriate. Furthermore, in FIGS. 7A to 7C, the contact area between the protrusion 425 of the hammer 42 and the two claws 455 of the anvil 45 is large. More specifically, the protrusion 425 of the hammer 42 collides with the claw portion 455 so as to contact substantially the entire side surface 4550 of the claw portion 455 . Note that when the hammer 42 moves forward to the front end of its movable range, the surface of the hammer body 420 on the output shaft 61 side (front surface 4201) and the surface of the claw portion 455 on the drive shaft 41 side (rear surface 4551) There is a gap between them.

In the state of FIG. 7B corresponding to time T1, the protrusion 425 of the hammer 42 (only one is shown in FIGS. 7B and 7C) is in contact with one of the two claws 455 of the anvil 45. From this state, the hammer 42 moves backward (moves upward in the drawing), so that the hammer 42 rotates over the two claws 455 of the anvil 45. As a result, the protrusion 425 of the hammer 42 collides with the next claw portion 455. That is, the state shown in FIG. 7C corresponding to time T5 is reached. The hammer 42 rotates half a rotation between time T1 and time T5. Thereafter, by a similar operation, the hammer 42 rotates half a rotation and returns to the state shown in FIG. 7B (time T1). That is, each time the hammer 42 makes a half rotation, the protrusion 425 collides with the two claws 455 alternately. In other words, the operations shown in FIGS. 7B and 7C are repeated every time the hammer 42 makes a half rotation.

In FIG. 7A, the current measurement value iq1 changes stably. In FIG. 7A, there is no pulse in the current measurement value iq1 between time T1 and time T5. In FIG. 7A, the current measurement value iq1 continues to fall below the first threshold Th1 between time T1 and time T5.

For example, the determination unit 84 determines the behavior of the impact mechanism 40 during the impact operation by determining that the measured current value iq1 continues to be lower than the first threshold Th1 in any of the four periods from time T1 to time T5. The type is determined to be "appropriate blow."

FIG. 8A corresponds to an example in which the impact action of the impact mechanism 40 is a "double strike" or a "rubbing up". FIGS. 8B to 8D correspond to cases in which the impact action of the impact mechanism 40 is a "double strike." "Double strike" means that the protrusion 425 of the hammer 42 collides with one of the two claws 455 of the anvil 45 (see FIG. 8B), and then collides with this claw 455 again (see FIG. 8C). , which collides with the other claw portion 455 (see FIG. 8D). "Rubbing up" means that after the protrusion 425 of the hammer 42 collides with one of the two claws 455 of the anvil 45, it moves to rub against the side surface 4550 of this claw portion 455 (in other words, it comes into contact with the side surface 4550). This is an operation of climbing over the claw portion 455 (while maintaining the same state).

"Double striking" and "rubbing up" may occur, for example, when the spring force of the return spring 43 that advances the hammer 42 is excessive. Further, "double striking" and "rubbing" may also occur when the number of revolutions of the electric motor 3 is insufficient. Further, "double hitting" and "rubbing up" may cause insufficient striking force in the striking operation of the impact mechanism 40.

In the case of "double strike", from time T1 when protrusion 425 of hammer 42 collides with one of the two claws 455 of anvil 45 to time T5 when it collides with the other, as shown in FIG. 8C, , collides again with the claw portion 455 that collided at time T1. As a result, as shown in FIG. 8A, the current measurement value iq1 temporarily increases at time T21 between time T2 and time T3. In FIG. 8A, the measured current value iq1 exceeds the second threshold Th2 at time T21. The second threshold Th2 may be the same as or different from the first threshold Th1 (see FIG. 7A).

For example, in the period between time T2 and time T3, the determination unit 84 determines that the type of behavior of the impact mechanism 40 during the impact operation is "double impact" when the current measurement value iq1 exceeds the second threshold Th2. Or, it is determined that the surface has rubbed off.

In FIGS. 9B to 9D, the not-illustrated area of the hammer body 420 of the hammer 42 is larger than in FIGS. 7B, 7C, and 8B to 8D, but the dimensions of the hammer 42 are the same. .

9A to 9D correspond to cases in which the striking action of the impact mechanism 40 is a "V-bottoming" action. "V-bottoming" means that after the protrusion 425 of the hammer 42 collides with one of the two claws 455 of the anvil 45 (see FIG. 9B), the hammer 42 moves forward to the front end of its movable range, and then, This is an operation in which the protrusion 425 collides with the other of the two claws 455 (see FIG. 9D). As the hammer 42 moves forward to the front end of its movable range, the steel balls 49 placed on the two V-shaped grooves 413 move into the grooves 413, as shown by solid lines in FIGS. 5 and 6. It collides with the inner surface corresponding to the center of the V-shape. In "V-bottoming", the protrusion 425 of the hammer 42 climbs over one of the two claws 455, moves in a V-shape, and collides with the other claw 455. That is, after the protrusion 425 of the hammer 42 passes over the claw portion 455, the hammer 42 moves forward (see FIG. 9C), and the forward momentum causes each steel ball 49 to hit the inner surface of the groove portion 413 corresponding to the center of the V-shape. collide. Thereafter, after the hammer 42 begins to retreat, the protrusion 425 of the hammer 42 and the claw portion 455 of the anvil 45 collide, as shown in FIG. 9D. In FIG. 9D, since the hammer 42 is retracted, the contact area between the protrusion 425 of the hammer 42 and the claw portion 455 of the anvil 45 is smaller than in the case of FIG. 9B.

"V-bottoming" may occur, for example, when the spring force of the return spring 43 that advances the hammer 42 is excessive. Further, "V bottoming out" may also occur when the rotational speed of the electric motor 3 is insufficient. Moreover, "V bottoming" may cause insufficient striking force in the striking operation of the impact mechanism 40.

In the case of "V bottoming", from time T1 when the protrusion 425 of the hammer 42 collides with one of the two claws 455 of the anvil 45 to time T5 when it collides with the other, each steel ball 49 It collides with the inner surface of the groove 413 corresponding to the center of the V-shape. As a result, as shown in FIG. 9A, the current measurement value iq1 temporarily increases at time T41 between time T4 and time T5. In FIG. 9A, the measured current value iq1 exceeds the third threshold Th3 at time T41. The third threshold Th3 may be the same as or different from the first threshold Th1 (see FIG. 7A) and the second threshold Th2 (see FIG. 8A).

For example, in the period between time T4 and time T5, the determination unit 84 determines that the type of behavior of the impact mechanism 40 during the striking operation is "V-bottoming" when the measured current value iq1 exceeds the third threshold Th3. ”.

As described above, the counter 86 counts the number of times that impact force is generated in a state where the behavior of the impact mechanism 40 determined by the determination unit 84 is "appropriate impact." For example, when the batting cycle is repeated N (N is a natural number) cycles, the discriminating unit 84 outputs N discriminating results corresponding to the N cycles, and the counter 86 outputs "appropriate batting" among the N discriminating results. ” is counted.

The determining unit 84 determines the state of the striking operation of the impact mechanism 40 based on the count number of the counter 86. The state of the batting motion output as the determination result of the determining unit 84 is, for example, a state in which there is an abnormality in the batting motion or a state in which there is no abnormality in the batting motion. In other words, the determining unit 84 determines whether or not there is an abnormality in the striking operation of the impact mechanism 40 based on the count of the counter 86. The output unit 85 notifies the determination result of the determination unit 84. For example, if the count number of the counter 86 is less than a predetermined number of times when the striking cycle is repeated N (N is a natural number), the determining unit 84 determines that there is an abnormality in the striking operation of the impact mechanism 40. In response to this, the output unit 85 notifies by sound or light that there is an abnormality in the striking operation of the impact mechanism 40. In other words, "a state in which there is no abnormality in batting motion" here refers not only to a state in which any type of batting motion other than "appropriate batting" is not included at all, but also to a state in which batting motions of types other than "appropriate batting" are within the permissible range. It can also include states contained within.

The control unit 7 controls the operation of the electric motor 3 based on the determination result of the determination unit 84. The determination result of the determination unit 84 includes, for example, information on the count number of the counter 86. For example, if the count number of the counter 86 is less than a predetermined number of times when the striking cycle is repeated N (N is a natural number), the control unit 7 controls the rotation speed of the electric motor 3 to increase or decrease. conduct. Further, the control unit 7 may determine whether to increase or decrease the rotation speed of the electric motor 3 depending on the type of striking motion determined by the determination unit 84. Reducing the rotation speed of the electric motor 3 also includes stopping the electric motor 3.

The control unit 7 controls the operation of the electric motor 3 based on the determination result of the determination unit 84 while the impact mechanism 40 is performing a striking operation. Thereby, when the type of behavior of the impact mechanism 40 during a striking operation is not "appropriate striking", the control over the electric motor 3 can be changed so that it becomes "appropriate striking". That is, the control unit 7 performs feedback control of the electric motor 3 using the determination result of the determination unit 84.

Note that the determining unit 84 is more suitable for determining the type of behavior of the impact mechanism 40 during a striking operation when tightening a bolt than when tightening a screw such as a wood screw. This is because a higher torque is often required to tighten a bolt compared to a screw, and as a result, changes in the current measurement value iq1 depending on the type of behavior of the impact mechanism 40 during a striking operation appear more pronounced. It's for a reason.

As described above, in the impact tool 1 of the present embodiment, the determination unit 84 determines the type of behavior of the impact mechanism 40 during impact operation by using the acquired torque current value (current measurement value iq1). I can do it. Thereby, it becomes possible to take measures according to the determination result of the determination unit 84.

An example of the countermeasure is to increase or decrease the rotation speed of the electric motor 3 according to the determination result of the determination unit 84. For example, the command value generation unit 71 of the control unit 7 may generate the command value cω1 of the angular velocity of the electric motor 3 according to the determination result of the determination unit 84. Further, in order to increase the rotational speed of the electric motor 3, a flux weakening current may be applied to the coil 321 of the electric motor 3. Furthermore, in order to reduce the rotational speed of the electric motor 3, a stronger magnetic flux current may be applied to the coil 321 of the electric motor 3.

Another example of countermeasure is to replace or repair members such as the return spring 43.

Another example of the countermeasure is for the control unit 7 to continue the control that was being executed on the electric motor 3 when the determination result of the determination unit 84 is “appropriate hit”.

In addition, the impact tool 1 of this embodiment employs vector control that controls the current supplied to the electric motor 3 based on the current measurement values id1 and iq1 of the d-axis current and the q-axis current. In the impact tool 1, the acquisition unit 90, which is also a configuration for vector control, can be used as a configuration for acquiring the current measurement value iq1. Then, the determining unit 84 determines the type of behavior of the impact mechanism 40 during the striking operation based on the current measurement value iq1 acquired by the acquiring unit 90. In other words, the impact tool 1 does not need to include a configuration for acquiring the current measurement value iq1 in addition to the configuration for vector control. Thereby, an increase in the number of components of the impact tool 1 can be suppressed.

Furthermore, one of a plurality of tip tools having different types, shapes, rigidities, etc. can be attached to the output shaft 61. Due to differences in the type, shape, rigidity, etc. of the tip tool, the type of behavior of the impact mechanism 40 may change. In this case as well, the determining unit 84 can determine the type of behavior of the impact mechanism 40 based on the acquired torque current value (current measured value iq1). Furthermore, since the control unit 7 controls the operation of the electric motor 3 based on the determination result of the determination unit 84, even if the type, shape, rigidity, etc. of the tip tool are changed, the type of behavior of the impact mechanism 40 during the striking operation will change. The electric motor 3 can be controlled so that the result is a "proper blow."

Further, the designer or the like can analyze the cause of the abnormality in the impact tool 1 based on the determination result of the determination unit 84.

(Modification 1)
As described in the embodiment, the determining unit 84 can determine the type of behavior of the impact mechanism 40 for each impact cycle. Here, the determining unit 84 may determine the type of behavior of the impact mechanism 40 during a period including a plurality of impact cycles, based on the determination result obtained for each impact cycle. For example, when the striking cycle is repeated N (N is a natural number), the discriminating unit 84 outputs N discrimination results for each striking cycle, and the type of behavior that is included in the N discrimination results is the largest number. may be output as the determination result in N cycles.

(Modification 2)
The determining unit 84 compares the measured current value iq1 with each of the plurality of model waveforms, and determines the type of behavior of the impact mechanism 40 during the striking action based on the matching rate between the measured current value iq1 and each model waveform. It's okay. A plurality of model waveforms have one-to-one correspondence with a plurality of behaviors such as "proper hit,""doublehit," and "rubbing up." The plurality of model waveforms are recorded in advance in the memory of the computer system that constitutes the control unit 7, for example. The determining unit 84 compares the measured current value iq1 with each of the plurality of model waveforms, and outputs the behavior corresponding to the model waveform with the highest matching rate with the measured current value iq1 as a determined result.

(Modification 3)
The type of behavior of the impact mechanism 40 during a striking action that is determined by the determining unit 84 is not limited to "proper hitting", "double hitting", "scuffing up", and "V-bottoming" described in the embodiment. . For example, the determining unit 84 may determine "maximum retraction" of the hammer 42 as one type of behavior of the impact mechanism 40.

When the hammer 42 is retracted to the maximum, the behavior of the hammer 42 becomes unstable compared to when the retracted distance of the hammer 42 is appropriate. That is, at this time, when a force in the direction of retreating is applied to the hammer 42, the hammer 42 cannot be retreated. Further, the force in the backward direction is absorbed by the hammer 42. This may reduce the life of the hammer 42.

Therefore, the determining unit 84 may detect the maximum retreat of the hammer 42 as one of the types of behavior of the impact mechanism 40 during a striking operation. For example, the determination unit 84 detects that the maximum retraction of the hammer 42 has occurred when the absolute value of the instantaneous value of the current measurement value iq1 of the torque current exceeds a threshold value. This threshold value is, for example, a different value from the first to third threshold values Th1 to Th3 described above.

The determining unit 84 may determine a specific situation in which maximum retraction occurs as one type of behavior of the impact mechanism 40. For example, the determining unit 84 may determine a situation in which a sign of maximum retreat appears as one type of behavior of the impact mechanism 40.

Further, the determining unit 84 may detect "top surface scraping" as one of the types of behavior of the impact mechanism 40 during a striking action. “Top surface scraping” is an operation in which the protrusion 425 of the hammer 42 comes into contact with one of the two claws 455 of the anvil 45 in the direction in which the hammer 42 moves forward. That is, in "top surface rubbing", the front surface 4251 (surface on the output shaft 61 side) of the protrusion 425 comes into contact with the rear surface 4551 (surface on the drive shaft 41 side) of the claw portion 455 (see FIG. 7B).

Further, the determining unit 84 may detect "shallow impact" as one of the types of behavior of the impact mechanism 40 during the impact operation. As shown in FIG. 8C, "shallow impact" means that the protrusion 425 of the hammer 42 and the claw part 455 of the anvil 45 collide in a limited area near the front end of the protrusion 425 and near the rear end of the claw part 455. This is an action to do. In the "shallow impact", unlike the "double impact", the protrusion 425 does not collide with the same claw portion 455 two or more times in a row.

"Top surface scraping" and "shallow impact" may occur, for example, when the rotational speed of the electric motor 3 is relatively high. Furthermore, "top scraping" and "shallow impact" may also occur when the spring force of the return spring 43 that advances the hammer 42 is insufficient. Moreover, "top surface scraping" and "shallow impact" may cause the impact force of the impact action of the impact mechanism 40 to become excessive.

For example, the determining unit 84 determines whether the type of behavior of the impact mechanism 40 during a striking action is "top scraping" based on the matching rate between the model waveform corresponding to "shallow hitting" and the measured current value iq1. It may also be determined whether the hit is a "shallow hit" or not.

The control unit 7 may reduce the rotation speed of the electric motor 3 when the determination unit 84 detects a behavior corresponding to an excessive rotation speed of the electric motor 3. Examples of behaviors corresponding to excessive rotational speed of the electric motor 3 are "maximum retreat," "top scraping," and "shallow impact." Further, the control unit 7 may increase the rotation speed of the electric motor 3 when the determination unit 84 detects a behavior corresponding to an insufficient rotation speed of the electric motor 3. Examples of behaviors corresponding to insufficient rotational speed of the electric motor 3 are "double hitting," "rubbing up," and "V bottoming out."

(Modification 4)
Similar to the embodiment, the acquisition unit 90 acquires the value of the torque current and the value of the excitation current supplied to the coil 321 of the electric motor 3. The determining unit 84 determines a torque current acquired value (current measurement value iq1) that is the value of the torque current acquired by the acquisition unit 90, and an excitation current acquisition value (current measurement value) that is the value of the excitation current acquired by the acquisition unit 90. Based on the value id1), the type of behavior of the impact mechanism 40 during the impact operation is determined. The acquisition unit 90 acquires the actual measured values of the torque current and the excitation current (current measurement values iq1, id1) as the acquired torque current value and the acquired excitation current value.

Similar to the embodiment, the determining unit 84 divides the period corresponding to the batting cycle into four equal parts, dividing the period between time T1 and time T2, the period between time T2 and time T3, and the time period between time T3 and time T4 and the period between time T4 and time T5. The determining unit 84 determines, for example, the number of pulses of the current measurement value id1 in each of these four periods, and determines the type of behavior of the impact mechanism 40 during the striking operation based on this result.

The determination unit 84 obtains a final determination result based on the determination result based on the current measurement value id1 and the determination result based on the current measurement value iq1. For example, when the determination result based on the current measurement value id1 and the determination result based on the current measurement value iq1 match, the determination unit 84 sets the determination result as the final determination result. Further, for example, when the determination result based on the current measurement value id1 and the determination result based on the current measurement value iq1 do not match, the determination unit 84 determines the final determination result as "abnormal". That is, at this time, the determining unit 84 determines that the type of behavior of the impact mechanism 40 is not at least a "proper impact."

Further, the determination unit 84 may change the weighting of the current measurement value id1 and the current measurement value iq1 in at least some types of behavior. In the impact tool 1 of the embodiment, "maximum retreat" and "top surface scraping" are easily determined based on the current measurement value id1, and "double strike", "rubbing up" and "V bottoming" are easily determined based on the current measurement value id1. It is easy to discriminate based on the measured value iq1. Therefore, for example, when the discrimination result based on the current measurement value id1 is "maximum retreat" or "top scraping" and the discrimination result based on the current measurement value iq1 is "appropriate impact", the discrimination unit 84 determines whether the current The determination result based on the measurement value id1 may be the final determination result. For example, the determination unit 84 may determine that the determination result based on the current measurement value id1 is "appropriate hit", and the determination result based on the current measurement value iq1 is "double hit", "scraping up", or "V bottoming out". '', the determination result based on the current measurement value iq1 may be the final determination result.

(Other variations of the embodiment)
Other modifications of the embodiment will be listed below. The following modified examples may be realized in combination as appropriate. Further, the following modified examples may be realized by appropriately combining with each of the above-mentioned modified examples.

The counter 86 may count the number of each discrimination result of the discrimination section 84. The counter 86 performs at least one of, for example, counting the number of "proper hits", counting the number of "double hits" and "rolling up", and counting the number of "V-bottom hits". It's okay.

When the control unit 7 changes the rotation speed of the electric motor 3 according to the determination result of the determination unit 84, a maximum variation width of the rotation speed may be set. The control unit 7 may change the rotation speed of the electric motor 3 by an amount smaller than the maximum variation width when the determination result of the determination unit 84 is a specific result. The control unit 7 may be configured not to change the rotation speed of the electric motor 3 any further when the amount of change in the rotation speed of the electric motor 3 reaches the maximum variation width. Alternatively, the control unit 7 may change the rotation speed of the electric motor 3 at predetermined time intervals until the amount of change in the rotation speed of the electric motor 3 reaches the maximum variation width. Further, when the determination result of the determination unit 84 is a specific result, the control unit 7 may immediately change the rotation speed of the electric motor 3 by the maximum change width.

The algorithm by which the determining unit 84 determines the type of behavior of the impact mechanism 40 during a striking operation may be changed depending on the type, rigidity, weight and dimensions of the tip tool, the type of load to be worked on, etc. . Examples of the types of loads include bolts, screws, and nuts.

The determining unit 84 may determine the type of behavior of the impact mechanism 40 during a striking action using a value obtained by removing a specific frequency component from the measured current value iq1 as the acquired torque current value.

The function of determining the state of the striking operation of the impact mechanism 40 based on the count number of the counter 86 may be provided in a structure other than the determining section 84.

The acquisition unit 90 is not limited to a configuration that acquires the current measurement value id1 as the excitation current acquisition value. The acquisition unit 90 may be configured to acquire the excitation current command value cid1 as the excitation current acquisition value. In this case, the acquisition section 90 includes at least the magnetic flux control section 76.

The acquisition unit 90 is not limited to a configuration that acquires the current measurement value iq1 as the torque current acquisition value. The acquisition unit 90 may be configured to acquire the torque current command value ciq1 as the torque current acquisition value. In this case, the acquisition section 90 includes at least the speed control section 72.

The acquisition unit 90 is not limited to a configuration in which the current measurement values id1 and iq1 are acquired by calculating the current measurement values id1 and iq1 by the acquisition unit 90 itself. The acquisition unit 90 may acquire the current measurement values id1 and iq1 from a configuration other than the acquisition unit 90.

The impact tool 1 is not limited to an impact driver, and may be, for example, an impact wrench, an impact drill, an impact drill driver, or the like.

In the impact tool 1 of this embodiment, the tip tool is replaceable depending on the purpose, but it is not essential that the tip tool is replaceable. For example, the impact tool 1 may be a power tool that can only use a specific tip tool.

The anvil 45 may hold the tip tool via the output shaft 61 etc. connected to the anvil 45, or may directly hold the tip tool.

The output shaft 61 may be formed integrally with the tip tool.

The impact tool 1 may include a buffer member for reducing the impact applied to the hammer 42 when the hammer 42 is at its maximum retreat. The buffer member is made of rubber, for example. When the hammer 42 retreats to the maximum, the hammer 42 hits the buffer member, so that the impact applied to the hammer 42 is alleviated.

The impact tool 1 may include a torque measuring section. The torque measuring section measures the operating torque of the electric motor 3. The torque measuring section is, for example, a magnetostrictive strain sensor capable of detecting torsional strain. The magnetostrictive strain sensor uses a coil installed in the non-rotating part of the motor 3 to detect changes in magnetic permeability in response to the strain caused by applying torque to the output shaft 61 of the motor 3, and generates a voltage signal proportional to the strain. Output.

The impact tool 1 may include a bit rotation measuring section. The bit rotation measuring section measures the rotation angle of the output shaft 61. Here, the rotation angle of the output shaft 61 is equal to the rotation angle of the tip tool (socket 62). As the bit rotation measuring section, for example, a photoelectric encoder or a magnetic encoder can be employed.

The impact tool 1 may include a shock sensor. The shock sensor outputs a voltage or current of a magnitude corresponding to the magnitude of vibration applied to the shock sensor. The counter 86 may count the number of times the impact force is generated in the impact mechanism 40 based on the output of the shock sensor. The shock sensor may be placed at a position where vibrations generated by the impact mechanism 40 are transmitted. For example, it may be arranged near the impact mechanism 40 or near the control section 7.

(summary)
The following aspects are disclosed from the embodiments described above.

The impact tool 1 according to the first aspect includes an electric motor 3, an impact mechanism 40, an acquisition section 90, and a determination section 84. The impact mechanism 40 receives power from the electric motor 3 and performs a striking operation that generates striking force. The acquisition unit 90 acquires the value of the torque current supplied to the electric motor 3. The determining unit 84 determines the type of behavior of the impact mechanism 40 during a striking action based on the torque current acquired value (current measurement value iq1) that is the value of the torque current acquired by the acquiring unit 90.

According to the above configuration, by using the torque current obtained value (current measurement value iq1), it is possible to determine the type of behavior of the impact mechanism 40 during a striking operation.

Further, in the impact tool 1 according to the second aspect, in the first aspect, the impact mechanism 40 generates impact force at every predetermined impact cycle in the impact operation. The determining unit 84 determines the type of behavior of the impact mechanism 40 during the impact operation based on the acquired torque current value (current measurement value iq1) between the start point and the end point of the impact cycle.

According to the above configuration, the determining unit 84 can determine the type of behavior of the impact mechanism 40 in response to the occurrence of one impact force. In other words, unlike the case where the type of behavior of the impact mechanism 40 is determined based on the torque current acquired value (current measurement value iq1) over a period in which the impact force is generated multiple times, the impact force of each impact force is It becomes possible to determine the type of behavior of the impact mechanism 40 corresponding to the occurrence.

Furthermore, in the impact tool 1 according to the third aspect, the impact period is calculated based on the rotation speed of the electric motor 3 in the second aspect.

According to the above configuration, the hitting period can be easily calculated.

Furthermore, the impact tool 1 according to the fourth aspect further includes an output section 85 in any one of the first to third aspects. The output unit 85 outputs the determination result of the determination unit 84.

According to the above configuration, the user or the like can confirm the determination result of the determination unit 84.

Furthermore, the impact tool 1 according to the fifth aspect further includes a control section 7 in any one of the first to fourth aspects. The control unit 7 controls the operation of the electric motor 3 based on the determination result of the determination unit 84.

According to the above configuration, the operation of the electric motor 3 can be controlled depending on the type of behavior of the impact mechanism 40 during a striking operation.

Furthermore, the impact tool 1 according to the sixth aspect further includes a counter 86 in any one of the first to fifth aspects. The counter 86 counts the number of times the striking force is generated.

According to the above configuration, by referring to the output of the counter 86 and the output of the determination unit 84, the user etc. can estimate the nature of the output of the counter 86 (for example, whether it is a normal output or not). can.

Further, in the impact tool 1 according to the seventh aspect, in the sixth aspect, the counter 86 counts the number of times the impact force is generated in a state where the behavior of the impact mechanism 40 determined by the determination unit 84 is a specific behavior. Count.

According to the above configuration, the user or the like can determine whether or not the specific behavior of the impact mechanism 40 continues based on the output of the counter 86.

Further, in the impact tool 1 according to the eighth aspect, in any one of the first to seventh aspects, the acquisition unit 90 acquires the actual measured value of the torque current (current measurement value id1) as the torque current acquired value. do.

According to the above configuration, the determination unit 84 determines the impact mechanism 40 in accordance with the actual operation of the impact mechanism 40, compared to the case where the target value of the torque current (command value ciq1) is used as the acquired torque current value. Can distinguish types of behavior.

Furthermore, in the impact tool 1 according to the ninth aspect, in any one of the first to eighth aspects, the acquisition unit 90 further acquires the value of the excitation current supplied to the electric motor 3. The determination unit 84 determines the torque current value (current measurement value iq1) acquired by the acquisition unit 90 and the excitation current acquisition value (current measurement value id1) which is the value of the excitation current acquired by the acquisition unit 90. , determines the type of behavior of the impact mechanism 40 during the striking operation.

According to the above configuration, the discrimination accuracy can be improved compared to the case where the discrimination unit 84 discriminates the type of behavior of the impact mechanism 40 based only on the acquired torque current value (current measurement value iq1). .

The configurations other than the first aspect are not essential to the impact tool 1 and can be omitted as appropriate.

1 Impact tool 3 Electric motor 7 Control section 40 Impact mechanism 86 Counter 90 Acquisition section 84 Discrimination section 85 Output section id1 Current measurement value (excitation current acquisition value)
iq1 Current measurement value (torque current acquisition value)

Claims (7)

electric motor and
an impact mechanism that performs a striking action that generates striking force by obtaining power from the electric motor;
an acquisition unit that acquires a value of torque current supplied to the electric motor;
A primary discrimination process based on a torque current acquired value , which is a value of the torque current acquired by the acquisition unit, and a secondary discrimination process based on the result of the primary discrimination process , perform the a determination unit that determines the type of behavior of the impact mechanism;
a counter that counts the number of times the striking force is generated ,
In the primary discrimination process, the discrimination unit discriminates a plurality of types of behavior including a plurality of types of abnormalities of the impact mechanism during the striking operation based on the torque current acquired value,
The counter counts, for each of the plurality of types of behavior, the number of times the impact force is generated in a state where the behavior of the impact mechanism determined in the primary determination process of the determination unit is the behavior;
In the secondary discrimination process, the discrimination unit determines that the behavior counted by the counter the most times among the plurality of types of behaviors is the behavior type of the impact mechanism during the hitting motion. do,
impact tools. The impact mechanism generates the impact force every predetermined impact cycle in the impact operation,
The determination unit determines the type of behavior of the impact mechanism during the impact operation based on the acquired torque current value between a start point and an end point of the impact cycle.
The impact tool according to claim 1. The striking period is calculated based on the rotation speed of the electric motor,
The impact tool according to claim 2. further comprising an output unit that outputs the discrimination result of the discrimination unit;
The impact tool according to any one of claims 1 to 3. further comprising a control unit that controls the operation of the electric motor based on the determination result of the determination unit;
The impact tool according to any one of claims 1 to 4. The acquisition unit acquires the actual measured value of the torque current as the torque current acquisition value.
Impact tool according to any one of claims 1 to 5. The acquisition unit further acquires a value of an excitation current supplied to the electric motor,
The determining unit is configured to determine whether the impact mechanism is operating during the striking operation based on the torque current acquired value acquired by the acquiring unit and the exciting current acquired value which is the value of the exciting current acquired by the acquiring unit. determine the type of behavior,
Impact tool according to any one of claims 1 to 6.

Images