JP6024974B2 - Impact rotary tool - Google Patents

Description

  The present invention relates to an impact rotary tool that includes an impact force generation unit that converts power of a drive source into an impact force that is a pulse-like torque, and that rotates a shaft portion to which a tip tool is attached using the impact force.

  An impact rotary tool is a tool that converts the rotation output of a motor, which is an example of a drive source, to a pulsed impact torque by hammering or hydraulic pressure, and performs tightening or relaxation work using the impact torque. is there. According to the impact rotary tool, workability is improved because a higher torque can be obtained as compared with the rotary tool using only the speed reduction mechanism. Therefore, impact rotary tools are widely used in construction sites and assembly factories (see, for example, Patent Documents 1 to 4).

  In impact rotary tools, the object may be over-tightened by high torque, but in order to avoid such over-tightening, the object is tightened loosely so that the object such as a bolt or screw has the desired strength. It may not be fixed. Therefore, in the impact rotary tool described in Patent Documents 1 and 2, a sensor such as a strain gauge or a torque sensor provided on the shaft portion measures the torque in order to tighten the object with a predetermined torque. When the torque based on the output value of the sensor reaches a predetermined torque such as a target torque, the driving of the motor is stopped.

  At this time, since the shaft portion on which the sensor is provided is a driving portion, noise is easily included in the output value of the sensor, and accurate torque measurement may be difficult. In particular, in the impact rotary tool, relatively large noise is likely to be generated when an impact force is applied to the shaft portion. In addition, since the torque applied to the shaft portion at the time of impact is pulsed, it is difficult to distinguish between impact pulses and noise during the output of the sensor. As a result, if noise is erroneously detected as torque, when the detected torque based on noise reaches a predetermined torque, the motor may be controlled to a predetermined driving state such as a stopped state. In this case, the impact rotary tool is stopped before the tightening torque reaches the predetermined torque. Therefore, in the impact rotary tool described in Patent Document 4, noise is removed from the sensor output from the strain gauge provided on the drive shaft of the pulse wrench by filter means such as a low-pass filter.

Japanese Utility Model Publication No. 1-106169 JP-A-8-267368 Japanese Patent Application Laid-Open No. 2010-12587 JP-A-11-267981

  However, according to the technique described in Patent Document 4, the structure of the impact rotary tool becomes complicated due to the filter means, and the cost for manufacturing the impact rotary tool increases. In addition, it is difficult to set the cutoff frequency of the filter means that distinguishes impact pulses from noise and removes only noise. For example, an impact wrench, which is one of impact rotary tools, has a more rapid change in torque than the pulse wrench disclosed in Patent Document 4, and thus it is more difficult to distinguish between an impact pulse and noise.

  The present invention provides an impact rotary tool that can reduce the inconvenience that a drive source is controlled to a predetermined drive state before the torque reaches a predetermined torque due to erroneous detection of torque caused by noise generated by impact impact. Objective.

  An impact rotary tool that solves the above-described problems is an impact force generator that generates an impact force by changing the power of a drive source to a pulsed torque, and transmits the pulsed torque to the tip tool by the generated impact force. A shaft, a torque detector that detects torque applied to the shaft and outputs a signal corresponding to the torque, a torque receiver that receives a signal corresponding to the torque output by the torque detector, and A control unit that controls the driving source to a predetermined driving state when a torque value obtained from a signal corresponding to the torque received by the torque receiving unit reaches a predetermined torque value, the torque detecting unit, When outputting a signal corresponding to the torque to the torque receiver, a signal corresponding to the torque is output with a delay from the time when the torque is actually detected.

  In the impact rotary tool, it is preferable that the torque detection unit and the torque reception unit are connected via a signal transmission unit capable of signal transmission between the rotation system and the fixed system.

  Further, in the impact rotary tool, the time to delay when the torque detector outputs a signal corresponding to the torque is such that the level of noise caused by the generation of the impact force is reduced to a preset level. It is preferable that the predetermined time or more is required.

  The impact rotary tool further includes an impact force detection unit that detects the impact force, and the torque detection unit has a magnitude of the impact force detected by the impact force detection unit equal to or less than a predetermined magnitude. In this case, it is preferable to output a signal corresponding to the torque to the torque receiving unit.

  In the impact rotary tool, the torque detector outputs a signal corresponding to the torque to the torque receiver when an output value of a signal corresponding to the detected torque becomes a predetermined value or less. It is preferable to do.

  According to the present invention, it is possible to reduce the inconvenience that the drive source is controlled to a predetermined drive state before the torque reaches a predetermined torque due to erroneous detection of torque caused by noise generated by impact impact.

The schematic sectional side view of the impact rotary tool in 1st Embodiment. A slip ring is shown, (a) is a sectional side view, (b) is a front view. The block diagram which shows the electrical structure of an impact rotary tool. (A) is a graph showing a torque detection signal based on the torque detected by the torque sensor, (b) is a graph showing a noise signal input to the main body control circuit when the output from the rotating unit control circuit is not delayed, (c) ) Is a graph showing a torque delay signal output with a delay from the rotation unit control circuit, and (d) is a graph showing a torque delay signal input to the main body control circuit when the output from the rotation unit control circuit is delayed. . The graph explaining a torque determination process. The schematic sectional side view of the impact rotary tool in 2nd Embodiment. The block diagram which shows the electrical structure of an impact rotary tool. (A) is a graph showing a torque detection signal based on the torque detected by the torque sensor, (b) is a graph showing an impact signal detected by the impact sensor, and (c) is a torque delay signal inputted to the main body control circuit. Graph. (A) is a graph which shows the torque detection signal based on the torque which the torque sensor in 3rd Embodiment detected, (b) is a graph which shows the torque delay signal input into a main body control circuit.

(First embodiment)
With reference to FIGS. 1-5, the structure of 1st Embodiment of an impact rotary tool is demonstrated.
As shown in FIG. 1, the impact rotary tool 11 is a hand-held type that can be held with one hand, and is, for example, an impact driver or an impact wrench. The main body housing 12 forming the exterior of the impact rotary tool 11 includes a bottomed cylindrical body portion 13 and a handle portion 14 extending from the body portion 13. The handle portion 14 extends in one direction intersecting the axis of the trunk portion 13 and extends downward from the trunk portion 13 in FIG.

  A motor 15 as an example of a drive source is disposed on the base end side in the body portion 13 and on the right end side in FIG. In the motor 15, the rotation axis of the motor 15 coincides with the axis of the body portion 13, and the output shaft 16 of the motor 15 faces the front end side of the body portion 13. The motor 15 is a DC motor such as a brush motor or a brushless motor, for example. An impact force generator 17 is connected to the output shaft 16 of the motor 15. The impact force generator 17 generates impact force by converting the rotational power of the motor 15 into pulsed torque.

  The impact force generation unit 17 includes a speed reduction mechanism 18, a hammer 19, an anvil 20, and a main shaft 21 that is an example of a shaft portion in order from the motor 15 side. The speed reduction mechanism 18 decelerates the rotation of the motor 15 at a predetermined speed reduction ratio, and the hammer 19 is transmitted with the speed reduced by the speed reduction mechanism 18 and increased in torque. The anvil 20 is struck by the hammer 19, and a rotational force is applied to the main shaft 21 by impact by the hammer 19. The main shaft 21 may be integrally formed with the anvil 20 as a part of the anvil 20, or the main shaft 21 formed separately from the anvil 20 may be fixed to the anvil 20.

  The hammer 19 is attached to a drive shaft 22 that is rotated by the output of the speed reduction mechanism 18. The hammer 19 is rotatable with respect to the drive shaft 22 and is slidable in the front-rear direction along the drive shaft 22. Further, the hammer 19 is urged toward the front side, which is the left side in FIG. 1, by the elastic force of the coil spring 24 interposed between the speed reduction mechanism 18 and the hammer 19, so that the hammer 19 comes into contact with the anvil 20. Be placed. A pair of contact portions 19 a extending toward the anvil 20 are equally arranged on the hammer 19 along the circumferential direction, and each contact portion 19 a and the contact portion 20 a extending in the radial direction of the anvil 20 and the circumferential direction. Abut. The rotation of the drive shaft 22 decelerated by the speed reduction mechanism 18 is transmitted to the main shaft 21 coaxial with the anvil 20 when the hammer 19 and the anvil 20 rotate together via the contact portions 19a and 20a. The A chuck portion 13a for attaching / detaching the tip tool 23 while being inserted into the socket hole is provided at the left end portion in FIG.

  When tightening of a fastening member such as a bolt or a screw is advanced by the rotation of the tip tool 23, for example, the load applied to the main shaft 21 is larger than that at the start of tightening of the fastening member. Or, when the loosening of the fastening member such as a bolt or a screw is advanced by the rotation of the tip tool 23, for example, the load applied to the main shaft 21 is small compared to the start of the loosening of the fastening member. In a state where a predetermined force or more is applied between the hammer 19 and the anvil 20, the hammer 19 is rearward along the drive shaft 22 while compressing the coil spring 24, and moves to the right in FIG. . When the hammer 19 is rotated by a certain amount or more with respect to the anvil 20 by such movement, the compressive force of the coil spring 24 is released, and the hammer 19 strikes the anvil 20 by the urging force of the coil spring 24 while rotating. . The hammer 19 is struck repeatedly each time the hammer 19 rotates more than a certain amount with respect to the anvil 20 due to the load received by the main shaft 21. The hit of the anvil 20 by the hammer 19 acts on the fastening member as an impact.

  As shown in FIG. 1, a torque sensor 26 and a rotating part control circuit 200 are attached to the main shaft 21 of the impact rotary tool 11. In the present embodiment, the torque sensor 26 and the rotating unit control circuit 200 constitute an example of a torque detecting unit that detects torque applied to the main shaft 21 and outputs a signal corresponding to the detected torque.

  Further, a slip ring 27 is attached to the main shaft 21, and the slip ring 27 transmits the output of the rotating part control circuit 200 from the main shaft 21 of the rotating system to the wiring of the main housing 12 of the fixed system. That is, in the present embodiment, the slip ring 27 constitutes an example of a signal transmission unit that can perform signal transmission between the rotating system and the fixed system. Since the slip ring 27 is used to transmit the output between the main shaft 21 and the main body housing 12, the rotation of the main shaft 21 can prevent the wiring from being twisted and the wiring from being entangled with the main shaft 21.

  The torque sensor 26 is a strain sensor capable of detecting torsional strain, and is bonded to the main shaft 21 with an adhesive. The torque sensor 26 is connected to the rotating part control circuit 200, detects shaft distortion generated when torque is applied to the main shaft 21, and outputs a voltage signal proportional to the distortion. The voltage signal output from the torque sensor 26 is a torque detection signal S1 (see FIG. 4) corresponding to the torque, and the torque detection signal S1 is output from the torque sensor 26 to the rotating part control circuit 200 attached to the main shaft 21. .

  The rotating unit control circuit 200 includes a delay circuit, and outputs the voltage signal input from the torque sensor 26 with a predetermined time delay. A signal output from the rotating unit control circuit 200 is input to the circuit board 28 provided in the main body housing 12 through the slip ring 27. A circuit board 28 provided in the handle portion 14 calculates a torque value from a signal output from the rotating portion control circuit 200, and performs a rotation control and torque setting of the motor 15 based on the calculation result. 30 is provided.

  The handle portion 14 is provided with a trigger lever 29, and the impact rotary tool 11 is driven when the trigger lever 29 is operated by an operator. In addition, a battery pack mounting portion 31 formed of a substantially square box-shaped storage case is detachably provided at the lower end of the handle portion 14, and a battery pack 32 that is a secondary battery is provided in the battery pack mounting portion 31. Contained. The impact rotary tool 11 is a rechargeable type using the battery pack 32 as a driving power source. The battery pack 32 is connected to the main body control circuit 30 through the power line 33.

  The motor 15 is provided with a speed detector 34 that detects the rotational speed of the motor 15. The speed detection unit 34 is embodied as a frequency generator that generates a frequency signal having a frequency proportional to the rotation speed of the motor 15, for example. The speed detection unit 34 may be, for example, an encoder, and when the motor 15 is a brushless motor, the speed detection unit 34 may be a Hall sensor, and detects the rotation speed based on the Hall sensor signal or counter electromotive force. Can do. The speed detection unit 34 outputs a signal corresponding to the rotation speed to the main body control circuit 30.

  The main body control circuit 30 is electrically connected to the motor 15 via the lead wire 35 and controls driving of the motor 15 and the like. Further, the main body control circuit 30 includes a signal line for inputting a signal from the rotation unit control circuit 200 to the main body control circuit 30, a power supply line for supplying power to the rotation unit control circuit 200, and a three conductor line including a ground line. The configured signal line 36 is connected.

  In FIG. 1, for convenience of illustration, three conductors that connect the slip ring 27 and the main body control circuit 30 are collectively shown as one signal line 36. As described above, the input of the signal from the rotation unit control circuit 200 to the main body control circuit 30 is performed via the slip ring 27. Furthermore, a trigger switch that detects the operation of the trigger lever 29 is electrically connected to the main body control circuit 30.

  The main body control circuit 30 performs control such as changing the rotation speed of the motor 15 in accordance with the pulling amount of the trigger lever 29 when the operator operates the trigger lever 29. The main body control circuit 30 controls energization to the motor 15 via a motor driver, and performs rotation control and torque setting of the motor 15. Further, the rotating part control circuit 200 outputs a signal corresponding to the distortion of the main shaft 21 detected by the torque sensor 26 as the torque detection signal S1. Then, the main body control circuit 30 outputs a stop signal or the like when the torque value calculated by calculation from the received signal exceeds the torque set value.

The configuration of the slip ring 27 will be described with reference to FIG.
As shown in FIGS. 2A and 2B, the case 42 constituting the slip ring 27 supports the rotary shaft 40 constituting the main shaft 21 via a plurality of bearings 41 so as to be rotatable. A plurality of signal lines 43 extending from the torque sensor 26 toward the slip ring 27 via the rotating unit control circuit 200 pass through the wiring holes 40 a formed in the rotating shaft 40 and collect current in the case 42. It is connected to the ring 44. For example, each of the three signal lines 43 extending from the torque sensor 26 is connected to a different current collecting ring. That is, in the case 42, three current collecting rings are provided. The current collecting ring 44 is fixed to the outer peripheral surface of the rotating shaft 40.

  As shown in FIG. 2B, a terminal box 48 is accommodated in the case 42, and the terminal box 48 supports each base end portion of the pair of arm portions 46 in a rotatable state. Has been. One brush 45 is attached to the distal end portion of each arm portion 46, and a spring 47 that biases the pair of arm portions 46 in a direction to approach the pair of arm portions 46 is connected between the pair of arm portions 46. The pair of brushes 45 is pressed against the outer peripheral surface of the current collecting ring 44 by the urging force of the spring 47.

  A torque detection signal S1 transmitted through the signal line 43 is input to the terminal box 48 via a current collecting ring 44 and a pair of brushes 45 that are transmission paths. A signal input to the terminal box 48 is sent to a plurality of terminal portions 49 which are fixed to the upper side in FIG. One of the conducting wires constituting the signal line 36 connected to the main body control circuit 30 is connected to the terminal portion 49. The output of the rotating unit control circuit 200 is input to the main body control circuit 30 through contact or sliding between the current collecting ring 44 and the brush 45 in the slip ring 27.

The electrical configuration of the impact rotary tool 11 will be described with reference to FIG.
As shown in FIG. 3, the impact rotary tool 11 is output from the rotary part control circuit 200 via the torque sensor 26, the rotary part control circuit 200 that inputs the signal output from the torque sensor 26, and the slip ring 27. And a main body control circuit 30 for inputting the received signal. The main body control circuit 30 includes a control unit 60 that performs torque management and speed control of the motor 15. The control unit 60 includes a torque setting unit 61 that sets a set torque that is a target value of the tightening torque. The main body control circuit 30 includes a recording unit 203 that records a torque value and the like.

  The torque setting unit 61 includes, for example, a volume and is electrically connected to the speed limit calculation unit 63 and the stop determination unit 66. The set torque for stopping the driving of the motor 15 is set by the operation of the torque setting unit 61 by the operator. For example, the torque setting unit 61 sets the target torque To (see FIG. 5) within a range of ± 10% of the set torque. The torque setting unit 61 may be configured so that the set torque itself is the target torque To. In the present embodiment, the target torque To corresponds to an example of a predetermined torque value.

  The control unit 60 includes a motor speed measurement unit 62 that measures the rotation speed of the motor 15, a speed limit calculation unit 63 that calculates a speed limit, and a motor control unit 64 that controls driving of the motor 15. The main body control circuit 30 is provided with a CPU, and the control unit 60 is composed of software in which the units 62 to 64 are constructed by the CPU executing a control program, for example. The units 62 to 64 constituting the control unit 60 are configured by hardware using an integrated circuit such as an ASIC, a part of the units 62 to 64 is configured by software, and the other part is hardware. It may be configured.

  The motor speed measuring unit 62 measures the rotational speed of the motor 15 based on a signal corresponding to the speed input from the speed detecting unit 34. The speed limit calculation unit 63 inputs the measured rotation speed of the motor 15 and a preset target torque To, and the motor 15 when the trigger lever 29 is pulled according to the magnitude of the target torque To. The speed limit speed is calculated. The motor control unit 64 controls the driving of the motor 15 so as to limit the rotation speed of the motor 15 to be equal to or lower than the limit speed. That is, when the target torque To is small, the motor control unit 64 limits the motor 15 to a speed that does not reach the maximum speed even when the trigger lever 29 is pulled to the maximum.

  The rotating unit control circuit 200 outputs a torque delay signal S3 (see FIG. 4) obtained by delaying the torque detection signal S1 detected by the torque sensor 26 by a predetermined time. The main body control circuit 30 includes a torque measuring unit 65 as an example of a torque receiving unit that receives the torque delay signal S3, and a stop determination unit that determines whether the torque value calculated from the torque delay signal S3 has reached the target torque. 66. Based on the received torque delay signal S3, the torque measurement unit 65 calculates, for example, a peak value in the torque delay signal S3 as a torque value. That is, the peak value in the torque delay signal S3 is the torque value. Torque measurement unit 65 outputs the measured torque value to stop determination unit 66.

  The main body control circuit 30 is provided with a CPU, and the torque measurement unit 65 and the stop determination unit 66 are composed of software in which the units 65 and 66 are constructed when the CPU executes a torque detection program and a determination program, for example. . Each unit 65 and 66 may be configured by hardware using an integrated circuit such as an ASIC, or a part of each unit 62 to 64 may be configured by software, and the other part may be configured by hardware. Good.

  Next, the operation of the impact rotary tool 11 of this embodiment will be described. For example, when the operator tightens a bolt, a screw, or the like, the torque setting unit 61 is operated in advance to set the set torque. When the operator operates the trigger lever 29, the impact rotary tool 11 is driven, whereby the tip tool 23 rotates to tighten bolts and screws.

  When the impact rotary tool 11 is driven, the rotation of the motor 15 is decelerated via the speed reduction mechanism 18, and the rotation whose torque is increased by the deceleration is transmitted to the main shaft 21 via the impact force generation unit 17. The tip tool 23 attached to is rotated.

  When a predetermined force or more is generated between the hammer 19 and the anvil 20, the hammer 19 rotates rearward along the drive shaft 22 against the urging force of the coil spring 24 while rotating with respect to the anvil 20. Slide. Thereby, the contact between the anvil 20 and the hammer 19 is released, and the hammer 19 strikes the anvil 20 by the elastic force of the compressed coil spring 24.

  As shown in FIG. 4 (a), the torque detection signal S1 detected by the torque sensor 26 in response to impact impact is a signal corresponding to the torque applied to the main shaft 21. (FIG. 4 shows the torque detection signal S1 for two strokes). By the way, noise accompanying impact shock or friction of the brush 45 against the rotating current collecting ring 44 is generated in the slip ring 27.

  Therefore, as shown in FIG. 4B, for example, when the torque detection signal S1 detected by the torque sensor 26 is immediately output to the main body control circuit 30 as it is, a noise signal on which noise N (see FIG. 4D) rides. S2 is output to the main body control circuit 30. When the torque value is calculated from the noise signal S2 including the noise N, the correct torque value cannot be calculated. That is, for example, when the peak value of the noise signal S2 is used as the peak value of the torque detection signal S1, an error from the actual torque value increases due to the influence of the noise N, and the calculation accuracy of the torque value decreases.

  Therefore, as shown in FIG. 4C, the rotating unit control circuit 200 of the present embodiment delays the torque detection signal S1 detected by the torque sensor 26 by a delay time t1 after starting to detect the torque detection signal S1. Torque delay signal S3 is output. Then, the rotation part control circuit 200 and the main body control circuit 30 can communicate with each other while the rotation of the anvil 20 is stopped or about to stop between the hits.

  As shown in FIG. 4D, when the rotating part control circuit 200 outputs the torque delay signal S3 obtained by delaying the torque detection signal S1 by the delay time t1, the main body control circuit 30 reduces the influence of the noise N. A torque delay signal S3 is received. That is, the torque delay signal S3 is input to the main body control circuit 30 at a timing different from the timing at which the noise N is input.

  The delay time t1 is a time equal to or longer than a predetermined time (t0) required for the level of the noise N generated with the generation of impact force to be reduced to a preset level. That is, the delay time t1 is the time until the rotation of the main shaft 21 stops due to the impact or the level of the noise N accompanying the rotation of the main shaft 21 becomes sufficiently small (in FIG. 4 (c) (d), the level is zero) The time is longer than the time and is a preset time. The delay time t1 is preferably set to a time shorter than the time from the start of detecting the torque detection signal S1 to the detection of the next torque detection signal S1. In other words, the delay time t1 is preferably set to a time shorter than the shortest time from when the hammer 19 strikes the anvil 20 until the next strike of the anvil 20.

  The determination process by the stop determination unit 66 will be described with reference to FIG. In the following, a case where the screw is fastened to the object by the impact rotary tool 11 will be described. In FIG. 5, the torque value calculated by the main body control circuit 30 is indicated by a solid line, and the torque delay signal S3 received from the rotating unit control circuit 200 is indicated by a broken line as an impact pulse I formed for each impact. . Further, in FIG. 5, the noise N received by the main body control circuit 30 is also indicated by a broken line.

  As shown in FIG. 5, immediately after the tightening of the screw by the impact rotary tool 11 is started, the anvil 20 is not hit by the hammer 19, so the torque value measured by the torque measuring unit 65 is increased as the tightening of the screw proceeds. Increase gradually. In contrast, when the hammer 19 strikes the anvil 20 due to the torque exceeding a certain value, the peak value in the torque delay signal S3 output from the rotating part control circuit 200, that is, the peak value for each impact pulse I is the torque. Stored as a value. Since the peak value of the impact pulse I gradually increases as the screw tightening progresses, the torque value measured by the torque measuring unit 65 is updated stepwise every time the impact pulse I occurs.

  Depending on the type of impact rotary tool, the peak value in the waveform of the voltage signal output from the torque sensor may be difficult to detect, or the correlation between the peak value in the waveform of the voltage signal and the actual torque may be low. In such a case, a parameter whose correlation with the torque is higher than the peak value, such as the area of the waveform output by one impact, that is, the area of one impact pulse I, is measured, and the torque value is estimated from this value. May be. The estimation of the torque value can be performed using a predetermined arithmetic expression or using a table created in advance.

  The stop determination unit 66 outputs a stop signal instructing the motor control unit 64 and the recording unit 203 to stop driving the motor 15 when the torque value becomes a torque value T exceeding the target torque To. Alternatively, even if the torque value is a value that does not exceed the target torque To, the stop determination unit 66 determines that the motor control unit 64 and the recording unit when the error between the target torque To and the torque value falls below a certain ratio. A stop signal for instructing the motor 15 to stop driving is output to 203.

  Then, the motor control unit 64 to which the stop signal from the stop determination unit 66 is input stops the driving of the motor 15. That is, the control unit 60 stops driving the motor 15 when the torque value obtained from the torque delay signal S3 received by the torque measuring unit 65 reaches the target torque To. As a result, when the tightening torque reaches the target torque To, the driving of the impact rotary tool 11 is stopped.

  The recording unit 203 records the torque value required for tightening for each work performed by the operator, the time required for tightening, and the like. Therefore, for example, after the work is completed, the operator can obtain the torque value and time for each work.

As described above, according to the impact rotary tool of the present embodiment, the following effects can be obtained.
(1) The rotating part control circuit 200 including a delay circuit delays and outputs the torque detection signal S1 detected by the torque sensor 26. Therefore, the torque delay signal S3 is input to the main body control circuit 30 at a timing at which the influence of the noise N accompanying the impact becomes small. Therefore, the accuracy of the comparison result between the torque value calculated from the torque delay signal S3 and the target torque To can be increased and the accuracy of the stop determination of the motor 15 can be increased as compared with the configuration without the delay circuit. As a result, it is possible to reduce the inconvenience that the motor 15 is controlled to the predetermined driving state before the torque reaches the predetermined torque due to the erroneous detection of the torque caused by the noise N generated by the impact of the impact.

  (2) The main shaft 21 of the rotating system and the main body housing 12 of the fixed system are connected using a slip ring 27. Therefore, when impact force is generated, noise N is generated in the slip ring 27. However, since the rotating part control circuit 200 outputs the torque delay signal S3, erroneous determination can be suppressed even when the slip ring 27 is used.

  (3) Since the delay time t1 is a time required for the level of the noise N generated with the generation of the impact force to decrease, the torque measuring unit 65 applies the torque delay signal S3 in which the influence of the noise N is reduced. Based on this, the torque value can be calculated.

(Second Embodiment)
The configuration of the second embodiment of the impact rotary tool will be described with reference to FIGS. The impact rotary tool in the second embodiment is different in configuration from the impact rotary tool in the first embodiment in that an impact sensor 201 is provided. Therefore, in the following, such differences will be described in detail.

  As shown in FIG. 6, an impact sensor 201 as an example of an impact force detector that detects an impact due to the impact of the hammer 19 is attached to the main shaft 21 in the vicinity of the hammer 19. The rotating part control circuit 200 is provided with a signal line 37 for inputting a signal from the impact sensor 201 to the rotating part control circuit 200. As the impact sensor 201, for example, an acceleration sensor that generates an electric charge when stress is applied is used. For the impact sensor 201, a microphone that detects a sound generated when the hammer 19 strikes the anvil 20 and outputs a detection signal may be used.

The electrical configuration of the impact rotary tool 11 will be described with reference to FIG.
As shown in FIG. 7, the rotation unit control circuit 200 includes a hit detection unit 202 that receives a signal from the impact sensor 201 and a delay circuit 204 that delays and outputs the torque detection signal S <b> 1 input from the torque sensor 26. With.

Next, an operation when the operator operates the trigger lever 29 of the impact rotary tool 11 of the present embodiment to tighten bolts, screws, and the like will be described.
As shown in FIG. 8A, the torque sensor 26 detects the torque detection signal S <b> 1 in the same manner as in the first embodiment along with the impact hitting and outputs it to the rotating part control circuit 200. On the other hand, as shown in FIG. 8B, the impact sensor 201 detects impact due to impact and outputs an impact signal S4 to the impact detection unit 202.

  Then, the delay circuit 204 compares the magnitude of the input impact signal S4 with the impact threshold value T1. Furthermore, when the magnitude of the impact signal S4 becomes smaller than the impact threshold value T1, the delay circuit 204 uses the torque detection signal S1 input from the torque sensor 26 at the timing when the preliminary time t2 has elapsed as the torque delay signal S3. Output to the main body control circuit 30. The impact threshold value T1 corresponds to an example of a predetermined size and is a predetermined value.

  That is, the torque detection signal S1 is output after being delayed by a delay time t3 obtained by adding the time required for the impact signal S4 to become smaller than the impact threshold value T1 and the spare time t2. Incidentally, both the noise N generated in the slip ring 27 and the impact due to the impact are generated along with the operation of the main shaft 21. Therefore, when the impact due to impact is reduced, the noise N generated in the slip ring 27 is also reduced.

  Therefore, as shown in FIG. 8C, the torque delay signal S3 is input to the main body control circuit 30 at a timing different from the timing at which the noise N is input. Since the impact signal S4 differs for each impact, the time from when the impact is detected until the impact signal S4 becomes smaller than the impact threshold T1 also changes. Therefore, the delay time t3 (t3 ') changes with each hit.

  As in the first embodiment, the main body control circuit 30 stops the driving of the motor 15 when the torque value obtained from the torque delay signal S3 received by the torque measuring unit 65 reaches the target torque To.

As described above, according to the impact rotary tool of the present embodiment, the following effects can be obtained in addition to the effects obtained by the impact rotary tool of the first embodiment.
(3) Since the delay time t3 can be set based on the detection result of the impact sensor 201, the rotating part control circuit 200 can quickly output the torque delay signal S3 at a timing when the influence of the noise N becomes small. it can. That is, it is possible to suppress the generation of noise N associated with the next blow during the communication between the rotating unit control circuit 200 and the main body control circuit 30.

(Third embodiment)
The configuration of the impact rotary tool in the third embodiment is the same as the configuration of the impact rotary tool in the first embodiment, but the time that the rotary unit control circuit 200 delays is different from that in the first embodiment. Therefore, in the following, such differences will be described in detail.

  As shown in FIG. 9A, the torque sensor 26 detects the torque detection signal S <b> 1 in the same manner as in the first embodiment in accordance with the impact hitting, and outputs it to the rotating part control circuit 200. Then, the rotating unit control circuit 200 compares the output value output from the torque sensor 26 as the torque detection signal S1 with the torque threshold T2. The torque threshold T2 corresponds to an example of a predetermined value, and is a predetermined value and may be zero.

  Furthermore, after the output value output as the torque detection signal S1 becomes larger than the torque threshold value T2, the rotating unit control circuit 200 outputs the torque delay signal S3 when the output value becomes equal to or less than the torque threshold value T2. That is, the rotating unit control circuit 200 uses the torque detection signal S1 input from the torque sensor 26 at the timing when the preliminary time t4 has elapsed from the timing when the output value of the torque sensor 26 becomes equal to or less than the torque threshold T2, as the torque delay signal S3. Output. Accordingly, the rotating unit control circuit 200 outputs the torque delay signal S3 after being delayed by the delay time t5 obtained by adding the time required for the output value of the torque sensor 26 to be equal to or less than the torque threshold T2 and the preliminary time t4.

  As shown in FIG. 9B, the torque delay signal S <b> 3 is input to the main body control circuit 30 at a timing when the noise N becomes small. Since the torque detection signal S1 is different for each impact, the time until the torque detection signal S1 becomes smaller than the torque threshold T2 also changes. Therefore, the delay time t5 (t5 ') changes with each hit.

  As in the first embodiment, the main body control circuit 30 stops the driving of the motor 15 when the torque value obtained from the torque delay signal S3 received by the torque measuring unit 65 reaches the target torque To.

As described above, according to the impact rotary tool of the present embodiment, the following effects can be obtained in addition to the effects obtained by the impact rotary tool of the first embodiment.
(4) By setting the delay time t5 based on the torque detection signal S1, an increase in the number of members can be suppressed. And the rotation part control circuit 200 can output the torque delay signal S3 rapidly at the timing when the influence of the noise N becomes small.

In addition, the said embodiment can be changed and implemented suitably as follows.
The preliminary times t2 and t4 may be zero.
The rotating unit control circuit 200 may process the torque detection signal S1 and output it in a state where the amount of information is reduced.

  The impact sensor 201 may be provided in the vicinity of the hammer 19 in the main body housing 12 that is a fixed portion. In this case, the impact signal S4 may be input to the rotating unit control circuit 200 via the slip ring 27. Further, the impact sensor 201 may input the impact signal S4 to the main body control circuit 30. That is, the main body control circuit 30 may issue an output command of the torque delay signal S3 to the rotating part control circuit 200 when the impact signal S4 becomes small.

  A rotation sensor that detects the rotation of the main shaft 21 or the anvil 20 may be provided. Then, the rotating unit control circuit 200 may output the torque delay signal S3 at a timing when the rotation of the main shaft 21 or the anvil 20 is stopped or is stopped based on the detection result of the rotation sensor.

  The stop of the motor 15 and the output shaft 16 is determined by the speed detector 34 that detects the rotational speed of the motor 15. By changing this, for example, a rotation sensor may be attached to a rotation shaft such as the main shaft 21 or the drive shaft 22, and the stop of the motor 15 and the output shaft 16 may be determined based on the output of the rotation sensor.

  The rotation speed of the motor 15 after the stop signal is output may not be directly detected by the speed detection unit 34. For example, an estimation circuit for estimating a change in the rotation speed of the motor 15 after the stop signal is output is provided, and the rotation of the motor 15 is stopped when the rotation speed estimated by the estimation circuit is “0”. It may be determined that That is, the rotation speed output unit that outputs a signal corresponding to the rotation speed of the drive source may be a circuit that detects the rotation speed of the motor 15 and outputs the detection result. A circuit that estimates and outputs the estimation result may be used.

  The member to which the torque sensor 26 is attached is not limited to the main shaft 21 but may be a member capable of detecting the torque applied to the main shaft 21 by the torque sensor 26, for example, the drive shaft 22, the anvil 20, and the hammer 19.

  -Although the predetermined drive state in the motor 15 which is a drive source was made into the stop state, it is good also as the deceleration state which reduces the rotational speed of the motor 15, for example. In this case, for example, when a deceleration start torque value smaller than the target torque To by a predetermined value is set and the torque value reaches the deceleration start torque value, control for decelerating the drive of the motor 15 is performed. Good. Further, after the motor 15 is driven for a predetermined time while being decelerated, the motor 15 may be controlled to stop. Further, the predetermined driving state of the motor 15 may be an acceleration state in which the rotation speed of the motor 15 is increased. In this case, for example, when the torque value reaches a predetermined torque value in order to retighten a screw or the like, until the main shaft 21 rotates by a predetermined rotation amount, or the torque value is increased and tightened. The motor 15 may be accelerated to a higher rotational speed until the target torque value is reached.

The motor 15 may be a DC motor or an AC motor other than the brush motor or the brushless motor.
The drive reduction of the impact rotary tool 11 is not limited to the motor, and may be a solenoid, for example. Moreover, not only an electric drive source such as a motor or a solenoid, but also a hydraulic drive source may be used. In this case, the drive source may be, for example, a hydraulic motor, and the output rotation thereof may be output to the impact force generation unit 17. Alternatively, the drive source may be a hydraulic cylinder and the impact force generation unit 17 may be pulsed by hydraulic force. The structure which generate | occur | produces a shape impact force may be sufficient. The driving source may be a pneumatic type.

The impact rotary tool 11 may be a non-rechargeable AC impact rotary tool.
The impact rotary tool may be a hammer drill, a circular saw, a jigsaw, a vibration driver, a grinder, a nailing machine, or the like in addition to the impact driver and impact wrench. Even in these cases, by providing the impact force generating portion, the impact force can be generated to rotate the shaft portion when the load applied to the shaft portion is large.

  DESCRIPTION OF SYMBOLS 11 ... Impact rotary tool, 12 ... Main body housing, 13 ... Body part, 13a ... Chuck part, 14 ... Handle part, 15 ... Motor, 16 ... Output shaft, 17 ... Impact force generation part, 18 ... Deceleration mechanism, 19 ... Hammer , 19a, 20a ... contact portion, 20 ... anvil, 21 ... main shaft, 22 ... drive shaft, 23 ... tip tool, 24 ... coil spring, 26 ... torque sensor, 27 ... slip ring, 28 ... circuit board, 29 ... trigger Lever, 30 ... body control circuit, 31 ... battery pack mounting part, 32 ... battery pack, 33 ... power line, 34 ... speed detection part, 35 ... lead wire, 36, 37, 43, 50 ... signal line, 40 ... rotating shaft , 40a ... hole, 41 ... bearing, 42 ... case, 44 ... current collecting ring, 45 ... brush, 46 ... arm part, 47 ... spring, 48 ... terminal box, 49 ... terminal part, 60 ... control part, 61 ... torque Setting , 62 ... Motor speed measurement unit, 63 ... Speed limit calculation unit, 64 ... Motor control unit, 65 ... Torque measurement unit, 66 ... Stop determination unit, 200 ... Rotation unit control circuit, 201 ... Impact sensor, 202 ... Impact detection , 203 ... recording unit, 204 ... delay circuit, I ... impact pulse, N ... noise, t1, t3, t5 ... delay time, t2, t4 ... preliminary time, T ... torque value, To ... target torque, T1 ... impact Threshold value, T2 ... Torque threshold value, S1 ... Torque detection signal, S2 ... Noise signal, S3 ... Torque delay signal, S4 ... Impact signal.

Claims (5)

An impact force generator that generates impact force by changing the power of the drive source to pulsed torque;
A shaft portion for transmitting a pulsed torque to the tip tool by the generated impact force;
A torque detector that detects torque applied to the shaft and outputs a signal corresponding to the torque;
A torque receiver for receiving a signal corresponding to the torque output by the torque detector;
A control unit that controls the drive source to a predetermined driving state when a torque value obtained from a signal corresponding to the torque received by the torque receiving unit reaches a predetermined torque value;
When the torque detection unit outputs a signal corresponding to the torque to the torque reception unit, the torque detection unit outputs a signal corresponding to the torque with a delay from a time when the torque is actually detected. Impact rotary tool. The impact rotary tool according to claim 1, wherein the torque detection unit and the torque reception unit are connected via a signal transmission unit capable of transmitting a signal between the rotation system and the fixed system. . The time to delay when the torque detector outputs a signal corresponding to the torque is equal to or longer than a predetermined time required for the level of noise generated with the generation of the impact force to be reduced to a preset level. The impact rotary tool according to claim 1, wherein the impact rotary tool is provided. Further comprising an impact force detector for detecting the impact force,
The torque detection unit outputs a signal corresponding to the torque to the torque receiving unit when the magnitude of the impact force detected by the impact force detection unit is equal to or less than a predetermined magnitude. The impact rotary tool according to claim 1 or 2. The torque detection unit outputs a signal corresponding to the torque to the torque receiving unit when an output value of a signal corresponding to the detected torque becomes a predetermined value or less. The impact rotary tool according to 1 or 2.