JP5144200B2 - Impact rotary tool - Google Patents

Description

  The present invention relates to an impact rotary tool that performs a tightening operation or a loosening operation by hammering.

  The impact rotary tool performs a tightening operation or a loosening operation by impacting the output shaft by impacting a hammer driven by rotation on the output shaft. In this impact rotary tool, a high tightening torque can be obtained as compared with a rotary tool that directly rotates the output shaft with a motor deceleration output.

  By the way, in the above impact rotary tool, there has been proposed one in which a setting input unit for inputting a set torque is provided, and the rotation is stopped when the tightening torque reaches the set torque input here.

  In the impact rotary tool described in Patent Document 1, a hit detection means for detecting a hit of an output shaft by a hammer using a microphone or the like, and a rotation angle detection for detecting a rotation angle of the output shaft using a photo interrupter or the like And the current tightening torque is calculated based on the detection results of both means, and the motor is forcibly stopped when the calculated tightening torque reaches the set torque.

  However, in the impact rotary tool, the output of the motor is constant regardless of the value of the installation torque. For this reason, for example, when the set torque is set to a small value in order to tighten the small screw, the impact force per one time is too large, and the tightening accuracy may be lowered. On the other hand, when the set torque is set to a large value in order to tighten the large screw, the impact force per one time is too small, and the tightening accuracy may be lowered.

  To solve this problem, it is conceivable to switch the output of the motor in accordance with the set torque value. That is, when the set torque is set to a small value, the motor speed is decreased, and when the set torque value is set to a large value, the motor speed is increased. As a result, it is possible to perform a tightening operation or the like with high precision with an impact force according to the operation.

However, when this is done, the following problems occur in the hit detection that is the basis for torque calculation. That is, in the impact detection means, the impact is detected when the output voltage from the microphone exceeds the detection threshold, but the output voltage and noise when generating a large impact force with the motor as a large output, It is difficult to collectively identify the output voltage and noise when generating a small striking force with a small output of the motor by the threshold value, and it is easy to cause a false detection of the striking.
JP 2000-354976 A

  The present invention has been invented in view of the above-described problems, and can perform work up to a set torque with a striking force according to work, and can perform work with high accuracy while preventing erroneous detection of striking. It is an object to provide an impact rotating tool.

In order to solve the above problems, the present invention provides a motor 1, a hammer 3 rotated by the motor 1, an output shaft 5 that is struck by the hammer 3 and applied with a rotational force, and an impact determination value used for impact detection has a threshold value. A hit detection unit 7 that detects a hit by the hammer 3 when exceeding, a torque calculation unit 17 that calculates a tightening torque based on a detection result of the hit detection unit 7, a setting input unit 18 that inputs a set torque, and a calculation In the impact rotary tool including the control unit 11 that stops the motor 1 when the tightening torque that has been set exceeds the set torque , the output of the motor 1 and the impact detection are increased as the set torque input by the setting input unit 18 increases. and the threshold for detection used in section 7, characterized in Rukoto switched to both increase.

In this way, by changing the output of the motor 1 so that the output becomes larger as the set torque input by the setting input unit 18 becomes larger , the impact force per time is set to the impact force according to the work. Is possible. In addition, for the threshold for detection using hitting detector 7, between Turkey switched to a larger threshold value as set torque increases, regardless of the output changes of the motor 1, appropriately output voltage and noise due to striking Thus, it is possible to discriminate between them and prevent erroneous detection of hitting.

The present invention also includes a motor 1, a hammer 3 rotated by the motor 1, an output shaft 5 that is struck by the hammer 3 and applied with a rotational force, and a hammer when a hit determination value used for hit detection exceeds a threshold value. 3, a hit detection unit 7 that detects a hit by 3, a torque calculation unit 17 that calculates a tightening torque based on a detection result of the hit detection unit 7, a setting input unit 18 that inputs a set torque, and the calculated tightening torque In the impact rotary tool including the control unit 11 that stops the motor 1 when the torque exceeds the set torque , the output of the motor 1 increases as the set torque input by the setting input unit 18 increases. Rukoto may be characterized switched to the amplification factor to amplify the batting judgment value decreases used.

Even in this case, by changing the output of the motor 1 so that the output becomes larger as the set torque input by the setting input unit 18 becomes larger , the impact force per time is set to the impact force according to the work. It becomes possible. In addition, for the amplification factor for amplifying the batting judgment value used by the striking detection section 7, in a Turkey switched to a small gain as set torque increases, regardless of the output changes of the motor 1, output by the striking Voltage and noise can be accurately identified, and erroneous detection of a hit is prevented.

  The invention according to claim 1 can perform the operation up to the set torque with the impact force according to the operation, and prevents the erroneous detection of the impact by switching the threshold value according to the set torque, with high accuracy. There is an effect that the work can be performed.

  Further, the invention according to claim 2 can perform the work up to the set torque by the striking force according to the work, and prevents the erroneous detection of the hit by switching the amplification factor according to the set torque. There is an effect that it becomes possible to work with accuracy.

  Hereinafter, the present invention will be described based on embodiments shown in the accompanying drawings. FIG. 1 schematically shows an example of an impact rotary tool according to an embodiment of the present invention.

  The impact rotary tool of this example includes a motor 1 that is a driving means, a speed reducer 2 that is a transmission mechanism that reduces the rotation of the motor 1 at a predetermined reduction ratio, and the rotation of the motor 1 is transmitted via the speed reducer 2. A hammer 3, an anvil portion 4 struck by the hammer 3, an output shaft 5 to which a rotational force is applied impactively when the hammer 3 strikes the anvil portion 4, and the anvil portion 4 of the hammer 3 Microphone 6 that converts the sound of the impact into a voltage signal, impact detector 7 that detects that the anvil 4 has been impacted by the hammer 3 because the value of the output voltage of the microphone 6 exceeds a predetermined threshold, and an output shaft 5 A disc-shaped light-shielding plate 8 having a plurality of slits (not shown) formed in the circumferential direction, and a photointerrupter 9 disposed so as to sandwich a portion of the light-shielding plate 8 where the slits are formed, , Photo in Waveform shaping of the signal output from the raptor 9 to generate a pulse signal having the number of pulses corresponding to the rotation angle of the output shaft 5, and tightening based on the outputs of the hit detection unit 7 and the waveform shaping circuit 10 The controller 11 calculates a torque and generates a stop signal for stopping the motor 1 when the tightening torque exceeds a set torque, and a trigger signal (speed command) St input by a trigger-like operation unit (not shown). And a motor drive unit 12 for rotating the motor 1 in response to the stop signal and stopping the rotation of the motor 1 in response to a stop signal input from the control unit 11.

  The control unit 11 includes a counter 13 as a rotation angle calculation unit that counts the number of pulses of the pulse signal input from the waveform shaping circuit 10, a timer 14 that generates an interrupt signal at regular time intervals, and a timer 14. The rotation speed calculation unit 15 that calculates the rotation speed of the output shaft 5 from the count value of the counter 13 from when the interrupt signal is input the previous time to the next input, and the impact detection unit 7 from the count value of the counter 13 A rotation angle calculation unit 16 that calculates the rotation angle of the output shaft 5 from when the previous hit is detected until the next hit is detected, and when the output shaft 5 is hit, the rotation speed calculation unit 15 The energy applied to the output shaft 5 is calculated from the calculated rotation speed of the output shaft 5, and the tightening torque is calculated from the energy and the rotation angle calculated by the rotation angle calculation unit 16 between hits. When only the torque exceeds the setting torque is composed of a torque calculating unit 17 for generating a stop signal for stopping the motor 1.

  The torque calculation unit 17 uses the relationship that the energy applied to the output shaft 5 when the hammer 3 strikes the anvil unit 4 is substantially equal to the energy consumed for tightening screws such as bolts and nuts. Is calculated. Since the calculation method is the same as the well-known method disclosed in Patent Document 1 and the like, the description thereof is omitted here.

  In this example, the setting input unit 18 for inputting the set torque to the torque calculation unit 17 and the predetermined threshold value used in the hit detection unit 7 according to the set torque input by the setting input unit 18 are set. And a threshold value changing unit 19 for switching. The control unit 11 is configured to switch the output (rotation speed) of the motor 1 according to the set torque input by the setting input unit 18.

  FIG. 2 mainly shows the hit detection unit 7 and the threshold value changing unit 19. The hit detection unit 7 has an output end connected to the input end of the rotation angle calculation unit 16 between hits, and a comparator in which a threshold voltage value (threshold value) determined by the threshold change unit 19 is applied to the inverting input terminal. Co1, a capacitor C2 having one end connected to the inverting input terminal of the comparator Co1, a capacitor C1 connected to the non-inverting input terminal of the comparator Co1, a resistor R2 to which the operating voltage Vd is applied to one end, and a resistor R2 A transistor Tr1 whose source is connected to the other end and the other end of the capacitor C1, one end connected to the drain of the transistor Tr1, and the other end connected to the resistor R3 connected to the capacitor C2, and the resistor R3 and the gate of the transistor Tr1 A resistor R1 connected to the output terminal of the comparator Co1 and one end to which the DC voltage Vd of the resistor R2 is applied. A diode D1 and resistors R4 connected in parallel to the series circuit of the resistor R2 and the capacitor C1, a diode D2 and resistor R5 Metropolitan is connected in parallel to a series circuit of a capacitor C1 and the transistor Tr1 and resistor R3. The microphone 6 is connected in parallel to the resistor R1 of the hit detection unit 7.

  The hammering sound detected by the microphone 6 is converted into a voltage signal, amplified by a predetermined amplification factor via the transistor Tr1 of the hammering detection unit 7, and then input to the non-inverting input terminal of the comparator Co1. . The voltage signal input to the non-inverting input terminal has a waveform as shown in FIG. 3, for example. In the waveform shown in the figure, an amplitude larger than that at other times t appears in the vicinity of each of the times t1 to t7 due to an impact sound of about 30 milliseconds (about 33.3 Hz).

  In the comparator Co1 of the hit detection unit 7, the voltage value of the voltage signal input to the non-inverting input terminal as described above is compared with the threshold voltage value (threshold value) input from the threshold value changing unit 19, and the former If the value is larger, it is determined that there is a hit and a rectangular wave hit detection signal is output to the input end of the rotation angle calculation unit 16 between hits. Thereby, the rotation angle calculation unit 16 between hits counts the number of hits assuming that there is a hit by the hammer 3 in the vicinity of each of the times t1 to t7 in FIG. 3, and the torque calculation unit 17 calculates the tightening torque based on this. To do.

  As described above, in this example, the voltage value of the voltage signal output from the microphone 6 is used as the hit determination value used for hit detection, but other values may be used as the hit determination value. Absent. For example, it is also preferable to provide an impact sensor instead of the microphone 6 and use the voltage value of the voltage signal output from the impact sensor as the hit determination value. Since the impact sensor uses a piezoelectric element in the same manner as the microphone 6, the circuit diagram is the same as that shown in FIG.

  In the threshold value changing unit 19, one of the transistors Tr2a to Tr2c is selected according to the set torque selected by the setting input unit 18, thereby changing the threshold voltage value input to the inverting input terminal of the comparator Co1. . As shown in FIG. 5, the setting input unit 18 can select a plurality of stages of setting torque (three stages of 100, 200, and 300 kgfcm in the illustrated example), and the control unit 11 can select the setting torque selected here. A signal is output to the motor drive unit 12 so as to rotate the motor 1 at a corresponding number of revolutions.

  Specifically, the rotation speed is set to increase as the selected set torque increases. In the illustrated example, the rotational speed is 1000 rpm when the set torque is 100 kgfcm, the rotational speed is 1200 rpm when the set torque is 200 kgfcm, and the rotational speed is 1500 rpm when the set torque is 300 kgfcm.

  Further, the control unit 11 outputs a signal to the threshold changing unit 19 so as to select a threshold voltage value (threshold value) corresponding to the set torque determined by the setting input unit 18. There are three threshold voltage values V1, V2 and V3 (V1 <V2 <V3) to be selected. When the set torque is 100 kgfcm and the rotation speed is 1000 rpm, the minimum threshold voltage value V1 and the set torque are When the engine speed is 200 kgfcm and the rotational speed is 1200 rpm, the intermediate threshold voltage value V2 is selected. When the set torque is 300 kgfcm and the rotational speed is 1500 rpm, the maximum threshold voltage value V3 is selected.

  Thus, by providing the rotational speed of the motor 1 so as to be increased as the set torque input by the setting input unit 18 increases, the tightening torque is set to the set torque by the striking force according to the work. It becomes possible to work until. In addition, the threshold voltage value for hit detection used in the hit detection unit 7 is also changed to a larger value as the set torque input by the setting input unit 18 increases (that is, as the rotation speed of the motor 1 increases). As shown in FIG. 4, when the impact force per time is small and the amplitude of the voltage signal is small, a small threshold voltage value is used accordingly, and the impact force is large. When the amplitude of the voltage signal increases, a large threshold voltage value is used accordingly. Therefore, it is possible to accurately identify the output voltage and noise due to the hitting, and the erroneous detection of the hitting is prevented.

  FIG. 6 is a flowchart showing the operation of the impact rotary tool of this example. As shown in the figure, the user first selects a set torque suitable for the work with the setting input unit 18, then pulls in the trigger-like operation unit, and drives the motor 1 at the rotation speed corresponding to the set torque. Here, the impact detection is performed using a threshold value corresponding to the selected set torque, the tightening torque is calculated based on the hit detection, and the motor 1 is stopped when the tightening torque becomes equal to or greater than the set torque.

  Next, another example of the impact rotary tool in the embodiment of the present invention will be described with reference to FIGS. Since the basic configuration of this example is the same as the configuration of the example described above, the description of the configuration that matches the configuration of the example is omitted, and only the characteristic configuration that is different from the configuration of the example is described below. It will be described in detail.

  In this example, the threshold voltage value is not changed by providing the threshold value changing unit 19 as in the example, but instead by providing the amplification factor changing unit 20, the voltage signal output from the microphone 6 is changed. The amplification factor for amplifying the voltage value is switched.

  In the amplification factor changing unit 20, one of the transistors Tr3a to Tr3c is selected according to the set torque selected by the setting input unit 18, and thereby the voltage value of the voltage signal input to the non-reverse input terminal of the comparator Co1. Is selected. The threshold voltage value input to the inverting input terminal of the comparator Co1 is a fixed value.

  The control unit 11 outputs a signal to the amplification factor changing unit 20 so as to select an amplification factor according to the set torque determined by the setting input unit 18. As shown in FIG. 8, there are provided three stages of selected amplification factors h1, h2, and h3 (h1> h2> h3), and the maximum amplification factor h1 when the set torque is 100 kgfcm and the rotation speed is 1000 rpm. When the set torque is 200 kgfcm and the rotational speed is 1200 rpm, the intermediate gain h2 is selected. When the set torque is 300 kgfcm and the rotational speed is 1500 rpm, the minimum gain h3 is selected.

  As described above, the amplification factor for amplifying the voltage value of the voltage signal from the microphone 6 that is the hit determination value used in the hit detection unit 7 increases as the set torque input by the setting input unit 18 increases (that is, the motor 1 By setting it to a smaller value (as the number of revolutions increases), it becomes possible to accurately identify the output voltage and noise due to impact, and to prevent erroneous detection of impact as in the case of an example. Become.

It is a schematic block diagram of an example impact rotary tool in embodiment of this invention. It is a schematic block diagram which shows the further principal part of an impact rotary tool same as the above. It is explanatory drawing which shows the waveform of the voltage signal output from the microphone of an impact rotary tool same as the above. It is explanatory drawing which shows the mode of the threshold value change of an impact rotary tool same as the above. It is explanatory drawing which shows the relationship between the setting torque of an impact rotary tool same as the above, the rotation speed of a motor, and a threshold voltage value. It is a flowchart which shows operation | movement of an impact rotary tool same as the above. It is a schematic block diagram which shows the principal part of the impact rotary tool of the other example in embodiment of this invention. It is explanatory drawing which shows the relationship between the setting torque of an impact rotary tool same as the above, the rotation speed of a motor, and an amplification factor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor 3 Hammer 5 Output shaft 7 Impact detection part 11 Control part 17 Torque calculation part 18 Setting input part 19 Threshold change part 20 Gain change part

Claims (2)

A motor, a hammer that is rotated by the motor, an output shaft that is struck by the hammer and to which a rotational force is applied, and a hammer detection unit that detects a hammer hit when a hit determination value used for hit detection exceeds a threshold; A torque calculation unit that calculates a tightening torque based on a detection result of the impact detection unit, a setting input unit that inputs a set torque, and a control unit that stops the motor when the calculated tightening torque exceeds the set torque. in rotary impact tool, the higher the setting torque inputted by the setting input unit is increased, the output of the motor, and the threshold for detection to be used in the striking detection unit, characterized in Rukoto switched to both increase Impact rotary tool. A motor, a hammer that is rotated by the motor, an output shaft that is struck by the hammer and to which a rotational force is applied, and a hammer detection unit that detects a hammer hit when a hit determination value used for hit detection exceeds a threshold; A torque calculation unit that calculates a tightening torque based on a detection result of the impact detection unit, a setting input unit that inputs a set torque, and a control unit that stops the motor when the calculated tightening torque exceeds the set torque. characterized in rotary impact tool, the higher the setting torque inputted by the setting input unit is increased, the output of the motor is increased, the Rukoto switched to the amplification factor to amplify the batting judgment value decreases used in hitting detector Impact rotary tool.

Images