JP2001219382A - Impact rotating tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an impact rotating tool to improve fastening torque precision by certainly detecting a stroke. SOLUTION: Three detection means made of a microphone 5a to output a detection signal by detecting striking sound by a hammer, a frequency generator 5b to output a detection signal of frequency roughly in proportion to the number of rotation of a motor 1 and a battery voltage detection circuit 5c to output a detection signal by detecting variation of both end voltage values of a battery 6 and a detection block 5d to separately process the detection signals to be output respectively from each of them are furnished. It is possible to improve fastening torque precision by precisely detecting a stroke by counting the number of strokes by a microcomputer 4 when the strike is discriminated by the detection signal from at least one of the detection means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact rotary tool such as an impact wrench or an impact driver used for tightening and loosening screws such as bolts and nuts.

[0002]

2. Description of the Related Art An impact rotary tool performs a tightening operation or a loosening operation of screws such as bolts and nuts by rotating an output shaft by applying a striking impact from a hammer driven to rotate to an output shaft. Such an impact rotary tool can obtain a higher tightening torque than a rotary tool that directly rotates the output shaft with the deceleration output of the motor, but on the other hand, when tightening small-diameter bolts and nuts, excessive tightening is required. It may cause damage, and if you fear that, stop the rotation of the motor provided inside early.
Tightening torque will be insufficient. In order to avoid breakage due to excessive tightening and insufficient tightening torque as described above, a conventional impact rotary tool sets a predetermined torque in advance and, for example, as shown in FIG.
A microphone 5a is attached to the housing 1a surrounding the microphone, the impact sound of the hammer is converted into an electric signal, the impact sound is counted by the processing circuit 13 connected to the microphone 5a, and the motor is stopped when the predetermined number of times is reached. .

[0003]

However, if the mating member to be fastened is soft, the hitting sound is low, and the hitting sound cannot be detected by the microphone 5a.
Conversely, the mating member is a painted bolt or wood,
If many hits must be made before seating, it is difficult to stop with an appropriate torque. Further, since the impact rotary tool is hardly used in a fixed place and is used in various places and situations, for example, when the tool comes into contact with members arranged in the vicinity, other impacts may occur. There has been a problem that the sound is detected and erroneously counted as a blow sound, and the rotation of the motor 1 is stopped early.

SUMMARY OF THE INVENTION An object of the present invention is to provide an impact rotary tool in which the accuracy of tightening torque is improved by reliably detecting an impact.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, a first aspect of the present invention is an impact rotary tool for applying a rotational force to an output shaft by hitting the output shaft with a hammer driven to rotate by a motor. A plurality of detecting means for detecting a plurality of types of different fluctuations caused by the impact of each of the different types and outputting a detection signal, and detecting the impact individually from the detection signals of the plurality of the detecting means, and outputting an impact detection signal A processing circuit and at least one of the plurality of detecting means;
Control means for counting the number of hits when it is determined to be a hit by a detection signal from one of them, and controlling the rotation speed of the hammer from a change in the number of hits within a certain period of time. Therefore, it is possible to prevent the erroneous detection of the impact by one type of detecting means and the processing circuit as in the conventional example, accurately detect the impact, and improve the tightening torque accuracy.

According to a second aspect of the present invention, in the first aspect of the present invention, a battery for supplying electric power to the motor is provided, and the plurality of detecting means detects a change in the voltage across the battery and outputs a detection signal. A detection circuit and a frequency generator that outputs a detection signal having an amplitude substantially proportional to the number of rotations of the motor are provided, and have the same effect as the first aspect of the invention.

According to a third aspect of the present invention, in the first aspect of the present invention, a battery for supplying electric power to the motor is provided, and the plurality of detecting means detects a change in the voltage across the battery and outputs a detection signal. It is characterized by a detection circuit and a microphone that detects a hitting sound of a hammer and outputs a detection signal,
The same operation as that of the first aspect is achieved.

According to a fourth aspect of the present invention, in the first aspect of the invention, the plurality of detecting means detect a striking sound generated by a hammer and a frequency generator for outputting a detection signal having an amplitude substantially proportional to the rotation speed of the motor. The microphone outputs a detection signal, and has the same effect as the first aspect of the invention.

According to a fifth aspect of the present invention, there is provided the frequency generator according to the first aspect, further comprising a battery for supplying electric power to the motor, wherein the plurality of detecting means output a detection signal having an amplitude substantially proportional to the number of rotations of the motor. A battery voltage detection circuit that detects a change in the voltage between both ends of the battery and outputs a detection signal; and a microphone that detects a hitting sound of a hammer and outputs a detection signal. The control circuit counts the number of hits when the processing circuit determines the hits at the same time from the detection signal from at least one of the battery power detection circuits, and the control circuit counts the number of hits. To play.

According to a sixth aspect of the present invention, in the first aspect of the present invention, there is provided a driving circuit including a switching element for driving a motor, and a PWM circuit for performing PWM control of the driving circuit. One is a pulse generator that outputs a detection signal having a frequency substantially proportional to the number of rotations of the motor. By using a pulse generator as the detection means, distortion of the detection signal waveform caused by the PWM control signal is reduced. Generation can be prevented, impact can be detected more reliably, and the tightening torque accuracy can be further improved.

According to a seventh aspect of the present invention, in the sixth aspect, the processing circuit comprises: a converter circuit for converting the detection signal output from the pulse generator into a voltage value substantially proportional to the frequency of the detection signal; A comparison circuit for comparing the voltage value obtained with the reference voltage value to determine the impact, and comparing the voltage value approximately proportional to the frequency of the detection signal with the reference voltage value to further reduce the impact. It is possible to reliably detect and further improve the tightening torque accuracy.

The invention of claim 8 is the invention of claim 2 or 4 or 5
In the invention according to any one of the first to third aspects, the processing circuit may include a peak hold circuit that detects a peak value of the detection signal output from the frequency generator, and a comparison that determines the impact by comparing the peak value of the detection signal with the reference voltage value. By comparing the peak value of the detection signal with the reference voltage value, the impact can be detected more reliably, and the tightening torque accuracy can be further improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) As shown in FIG. 1, an impact rotary tool according to the present embodiment includes a battery 6 provided therein and a motor 1 for rotating a hammer by electric power supplied from the battery 6. A driving circuit 2 that includes an FET as a switching element to drive the motor 1 by varying the power supplied to the motor 1, a PWM circuit 3 that performs PWM control of the driving circuit 2, and a rotation speed of the motor 1 that is controlled by the PWM circuit 3. A microcomputer (hereinafter abbreviated as "microcomputer") 4 as a control means for outputting a signal to be controlled; and a plurality of different types of fluctuations caused by the impact of the hammer, which are different from each other, are detected for each type, and an impact detection signal is output to the microcomputer 4. And a power supply corresponding to each of the PWM circuit 3, the microcomputer 4, and the impact detection circuit 5 are generated by using the battery 6 as a power supply. And a power supply circuit 7 for feeding.

The striking detection circuit 5 detects a striking sound of a hammer and outputs a detection signal, a microphone 5a for generating a detection signal having an amplitude substantially proportional to the rotation speed of the motor 1, and a voltage across the battery 6. And three detection means including a battery voltage detection circuit 5c for detecting a change in the detection voltage and outputting a detection signal, and a detection block 5d for separately processing the detection signal output from each of them.

The microphone 5a is mounted on a housing 1a surrounding the motor 1 as shown in the prior art, and
Is output to the microphone processing circuit 5d1 inside the detection block 5d. Processing circuit 5
d1 compares the voltage value of the detection signal with the reference voltage value, and when the voltage value of the detection signal is larger than the reference voltage value, determines that a strike has occurred, and outputs a rectangular wave strike detection signal to the input terminal of the microcomputer 4. Output to P.

The microphone processing circuit 5d1 has an output terminal connected to the input terminal P of the microcomputer 4, as shown in FIG.
A comparator Co1 to which a reference voltage at an output terminal DA of the microcomputer 4 is applied to an inverting input terminal, a capacitor C2 having one end connected to the inverting input terminal of the comparator Co1, and a capacitor C1 connected to a non-inverting input terminal of the comparator Co1. And a resistor R2 to one end of which an operating voltage Vd is applied.
A transistor Tr1 whose source is connected to the other end of the resistor R2 and the other end of the capacitor C1,
1 has one end connected to the drain and the other end connected to a capacitor C2.
, The resistor R3 and the transistor Tr
A diode connected in parallel to a series circuit of a resistor R1 connected to the gate of the first resistor R1, a resistor R6 connected to one end of the resistor R2 to which the DC voltage Vd is applied and the output terminal of the comparator Co1, and a resistor R2 and a capacitor C1. D1 and a resistor R4, and a diode D connected in parallel to a series circuit of a capacitor C1, a transistor Tr1, and a resistor R3.
The microphone 5a is connected in parallel to the resistor R1 of the processing circuit 5d1 for the microphone.

The striking sound is converted to a voltage signal by the microphone 5a, and the transistor T of the microphone processing circuit 5d1 is turned on.
It is amplified via r1 and input to the non-inverting input terminal of the comparator Co1. The voltage signal input to the non-inverting input terminal has, for example, a waveform as shown in FIG. 3, and each time from time t1 to time t7 is output by a beeping sound every about 30 msec (about 33.3 Hz). A waveform having a larger amplitude than that at time t appears. The processing circuit 5d1 includes a comparator C
At o1, the voltage signal input to the above-mentioned non-inverting input terminal is compared with the reference voltage of the microcomputer 4, and if the voltage signal is larger than the amplitude W, it is determined that an impact has occurred. Is output to the input terminal P. The microcomputer 4
It is possible to count and process the number of hits assuming that a hammer has hit the golf ball near each of the times t1 to t7.

In the detection of the striking sound by the microphone 5a, the amplitude of the waveform at times t2 and t3 is smaller than the amplitude W, so that the processing circuit 5d1 may erroneously determine that no striking has occurred. is there. Such an erroneous determination can be prevented by the frequency generator 5b, the battery voltage detection circuit 5c, and the detection block 5d. Hereinafter, the frequency generator and the battery voltage detection circuit 5
c will be described in detail.

As shown in FIG. 4, the frequency generator 5b is provided in the motor 1, and a detection signal output from the frequency generator 5b and having an amplitude substantially proportional to the number of revolutions of the motor 1 is supplied to the frequency generator 5d inside the processing circuit 5d. It is input to the processing circuit 5d2 for the generator.

Processing circuit 5d2 for frequency generator
5, a comparator Co2 whose output terminal is connected to the input terminal P of the microcomputer 4, and a comparator C
A series circuit of a capacitor C3 and a resistor R7 connected to the inverting input terminal of o2, a series circuit of resistors R8 and R9 connected to the non-inverting input terminal of the comparator Co2, and an output terminal and an inverting input terminal of the comparator Co. And a resistor R12 connected to an output terminal and a non-inverting input terminal of the comparator Co.
And a resistor R1 connected to one end of the resistor R9 to which the resistor R8 is not connected and to the inverting input terminal of the comparator Co.
3, a diode D3, a capacitor C4, and a resistor R
11 and a resistor R8, R
9 and a resistor R14 connected to a connection point between the resistors R10 and R11. The frequency generator 5d is connected to one end of the resistor R7, which is not connected to the capacitor C3, and to the connection point of the resistors R9, R13.

As shown in FIG. 6A, the processing circuit 5d2 determines that a hammer has been hit when a detection signal having an amplitude equal to or greater than Vt is input from the frequency generator 5d. As shown, a rectangular wave impact detection signal is output from the output terminal of the comparator Co2 to the input terminal P of the microcomputer 4.

The battery voltage detection circuit 5c is connected to both ends of the battery 6 and constantly measures the voltage V across the battery 6, as shown in FIG.

For example, as shown in FIG. 8, the waveform of the detection signal output from the battery voltage detection circuit 5c is from time t8 to time t8.
9 when the hammer is hitting the battery approximately periodically.
The value of the voltage V between both ends rapidly increases substantially periodically. Such a rapidly rising pulse waveform is generated by hammering.

The detection block 5d includes, for example, a processing circuit for a battery voltage detection circuit similar to the processing circuit 5d1 for a microphone. When a detection signal having an amplitude larger than the amplitude set in this processing circuit is input, A rectangular wave impact detection signal is output to the input terminal P of the microcomputer 4.

As described above, the input terminal P of the microcomputer 4 includes the microphone processing circuit 5d1, the frequency generator processing circuit 5d2, and the battery voltage detection circuit processing circuit provided in the detection block 5d. The detection signal of the rectangular wave which is output when it is determined that the hammer has been hit is input. When the microcomputer 4 receives a detection signal of any one of the processing circuit 5d2 for the frequency generator, the processing circuit 5d1 for the microphone, and the processing circuit for the battery voltage detection circuit, the microcomputer 4 determines that the hammer has been hit, The number of hits is counted. Then, the microcomputer 4 calculates a change in the number of hits within a certain period of time, and outputs a signal for controlling the rotation speed of the motor 1 to the PWM circuit 3 when the change in the number of hits is greater than a predetermined value.

In this embodiment, three different detecting means and processing circuits respectively corresponding to the three detecting means are provided, and the impact is determined by at least one of the detection signals. It is possible to control and improve the tightening torque accuracy.

By the way, the detection signal from the frequency generator processing circuit 5d2 and the microphone processing circuit 5d1
Alternatively, when the detection signal from either one of the processing circuits for the battery voltage detection circuit is input to the microcomputer 4 substantially at the same time, it is determined that the hammer has been hit, and the number of hits is counted. good.

The microcomputer 4 further includes any two of the microphone 5a, the frequency generator 5b, and the battery voltage detecting circuit 5c, and a processing circuit corresponding to each detecting means.
When a hit detection signal is output from any one of the processing circuits to the microcomputer 4, it may be determined that a hammer has hit, and the number of hits may be counted. Also,
Instead of the battery voltage detection circuit 5c, the motor 1
A current detection circuit that detects a change in the value of the current flowing through the sensor and outputs a detection signal may be provided.

Since the mounting work of the microphone 5a requires mounting accuracy, it is difficult to manufacture the tool, and the mounted microphone 5a is affected by lubricating oil and dust of the rotating mechanism of the motor 1. I will. Therefore, without using the microphone 5a, the frequency generator 5b and the battery voltage detection circuit 5
When c is used, the tool can be easily manufactured, and can be installed in a place that is not affected by lubricating oil or dust. (Embodiment 2) This embodiment is characterized by a processing circuit 5d2 for a frequency generator, and the other configuration is common to that of Embodiment 1. Therefore, common portions are denoted by the same reference numerals and description thereof is omitted. I do.

As shown in FIG. 9, the processing circuit 5d2 of the present embodiment comprises a peak hold circuit 5 for holding the peak value of the voltage of the detection signal output from the frequency generator 5b.
e and a comparison circuit 5f that compares the peak value held by the peak hold circuit 5e with a reference voltage value, and outputs a rectangular wave impact detection signal when the peak value is smaller than the reference voltage value.

As shown in FIG. 10, the peak hold circuit 5e includes a diode D having an anode connected to an input terminal I1 to which a detection signal from the frequency generator 5b is input.
5, an operational amplifier A1 having a non-inverting input terminal connected to the cathode of the diode D5, a diode D6 and a resistor R6 connected to the input terminal I1 and the output terminal of the operational amplifier A1.
15 series circuits, a diode D5 and an operational amplifier A1.
And a series circuit of a resistor C16, a resistor R16, and a switch SW, one end of which is connected to the connection point and the other end is grounded. The series circuit of the diode D6 and the resistor R15 reduces the reverse leakage current of the diode D5 to improve the output response time of the operational amplifier A1.

The comparison circuit 5f includes a comparator Co3 having an inverting input terminal connected to the output terminal of the operational amplifier A1,
The comparator Co3 includes a reference power supply E1 having a positive electrode connected to the non-inverting input terminal and a negative electrode grounded.

The processing circuit 5d2 utilizes the fact that the amplitude of the waveform of the detection signal output in accordance with the rotation speed of the motor 1 of the frequency generator 5b constantly changes. For example, the switch S of the peak hold circuit 5
When W is turned off and a detection signal having a waveform as shown in FIG. 11 is output from the frequency generator 5b and input to the input terminal I1, the peak hold circuit 5 sets the voltage value Vp1 that peaks around time t10 to Vp1. Hold the corresponding charge,
A voltage signal corresponding to the voltage value Vp1 is output to the comparator Co3 of the comparison circuit 5f. Then, the switch SW of the peak hold circuit 5 is turned on under the control of the microcomputer 4, resets the electric charge held by the peak hold circuit 5, and is then turned off again. Thus, the switch S
W is periodically turned on / off, and the peak hold circuit 5
The same operation is repeated even if a detection signal having a voltage value Vp2 having a peak near time t11 is input next.

The comparator Co3 inputs voltage signals corresponding to the voltage values Vp1 and Vp2 output from the output terminal of the operational amplifier A1, and compares the voltage values of the voltage signals with the reference power supply E1.
Compared to the reference voltage value, when it is smaller than the reference voltage value,
A rectangular wave impact detection signal is output from the output terminal O1. By determining the impact by comparing with the reference voltage value, the impact detection can be made more accurate, and the tightening torque accuracy can be further improved. (Embodiment 3) In the present embodiment, the frequency generator 5b
Is characterized in that a pulse generator 8 which is an optical encoder and a processing circuit 8a for the pulse generator are used instead of the processing circuit 5d2, and the other configuration is common to the first embodiment. Are denoted by the same reference numerals and description thereof is omitted.

FIG. 12 and FIG.
As shown in FIG. 3, a substantially disc-shaped detection is provided in which a plurality of slits 12 are attached to a through hole 11 formed in a substantially central portion through a rotating shaft 1b of the motor 1 and are arranged at substantially equal intervals in a peripheral portion. It has a board 8b and a photointerrupter 8c arranged so as to sandwich a portion of the detection board 8b where the slit 12 is formed.

As shown in FIG. 14, the photo-interrupter 8c has a light emitting diode D
7 and a phototransistor Tr2. When the phototransistor Tr2 receives light from the light emitting diode D7, it conducts between the collector and the emitter.

The processing circuit 8a includes a comparator Co4 having an output terminal connected to the input terminal P of the microcomputer 4, an inverting input terminal of the comparator Co4, and a phototransistor Tr.
, The non-inverting input terminal of the comparator Co4 and the phototransistor Tr2.
And a resistor R21 connected to the output terminal of the comparator Co4 and the collector of the phototransistor Tr2.
A diode D8 connected in parallel to a series circuit of the phototransistor Tr2 and the resistor R17;
20, a connection point of the diode D9 connected in parallel with the resistors R18 and R19 and the phototransistor Tr.
, A resistor R22 connected to the collector of
An anode of the light emitting diode D7 is connected to a collector of the phototransistor Tr2, including a connection point of R20 and a resistor R23 connected to a cathode of the light emitting diode D7.

By using the pulse generator 8 and the processing circuit 8a as described above, the detection board 8b rotates with the rotation of the rotating shaft 1b of the motor 1, and the slit 12 of the detection board 8b substantially faces the phototransistor Tr2. ,
Light emitted from the light emitting diode D7 passes through the slit 12 and is received by the phototransistor Tr2. At this time, when the collector and the emitter of the phototransistor Tr2 conduct, and the rotating shaft 1b is rotating at a substantially constant speed, the output terminal of the comparator Co4 outputs a rectangular having a substantially constant period as shown in FIG. A wave detection signal is output.

For example, when there is no impact as shown in FIG. 16A, the rotating shaft 1b rotates at a rotation speed of about 18000 rpm at full throttle (without PWM control), and the time difference tw1 between the rectangular waves. Is about 170 to 195 microseconds. On the other hand, when there is a hit as shown in FIG. 16 (b), the rotation shaft 1b is about 1100 at full throttle.
It rotates at a rotation speed of 0 rpm, and the time difference tw2 between the rectangular waves is about 290 to 340 μsec. In addition, FIG.
The duty ratio of each waveform in FIG.
３８38%. As described above, the time difference between the rectangular waves tw1 and tw2 is different between the case where there is an impact and the case where there is no hit, and the number of rectangular waves output within a certain time is different. The microcomputer 4 can detect that there is a hit if the count number is small by counting the rectangular waves within the predetermined time.

By the way, from the PWM circuit 3, a P which turns on / off the FET of the drive circuit 2 at an arbitrary on-duty.
The WM control signal is output. In the first and second embodiments, for example, as shown in FIG. 17B, when the PWM control signal is output between around time t12 and t13 and between around time t14 and t15, As shown, distortion occurs in the waveform of the detection signal output from the frequency generator 5b.

On the other hand, in the present embodiment, distortion of the detection signal output from the pulse generator 8 due to the PWM control signal is suppressed, and the impact detection can be made more accurate to improve the tightening torque accuracy. (Embodiment 4) This embodiment is characterized in the processing circuit 8a for the pulse generator, and the other configuration is common to that of the third embodiment. I do.

As shown in FIG. 18, an F / V converter circuit 8a1 for inputting a detection signal output from the pulse generator 8 and converting the frequency of the detection signal into a voltage value, as shown in FIG. Comparing the voltage value of the voltage signal output from the band-pass filter circuit 8a2 with the reference voltage value and extracting a voltage value smaller than the reference voltage value,
A comparison circuit 8a3 that outputs a rectangular wave impact detection signal.

As shown in FIG. 19, the F / V converter circuit 8a1 includes an operational amplifier A2 and a pulse generator 8
And a capacitor C6 connected to an input terminal I2 for inputting a signal from the input terminal and an inverting input terminal of an operational amplifier A2.
And a series circuit of a diode D10 and an operational amplifier A2.
R25 and a capacitor C7 connected to the inverting input terminal and the output terminal of the
An anode is connected to the connection point 10 and a diode D11 whose cathode is grounded. The non-inverting input terminal of the operational amplifier A2 is grounded. As shown in FIG. 20, a detection signal of the voltage value Vs output from the pulse generator 8 is input to the input terminal I2 of the F / V converter circuit 8a1. The pulse of this detection signal is integrated, and a charge Q obtained by multiplying the capacitance value C6n of the capacitor C6 by the voltage value Vs is accumulated in the capacitor C7. As a result, a voltage signal having a voltage value substantially proportional to the frequency of the detection signal is output from the output terminal of the operational amplifier A1.

The band-pass filter circuit 8a2 includes an operational amplifier A3, a series circuit of a resistor R26 and a capacitor C8 connected to an output terminal of the operational amplifier A2 of the F / V converter circuit 8a1 and a non-inverting input terminal of the operational amplifier A3, and a resistor R26. One end is connected to the connection point of the capacitor C8 and the other end is connected to the connection point of the resistor R27 whose other end is connected to the output terminal of the operational amplifier A3 and the non-inverting input terminal of the operational amplifier A3. It comprises a grounded capacitor C9 and a resistor 28, and the inverting input terminal of the operational amplifier A3 is connected to the output terminal.

The band-pass filter circuit 8a2 includes an operational amplifier A3, capacitors C8 and C9, and a resistor R2
6, R27, and R28, it is configured as a multiple feedback type using an inverting amplifier. By setting the center frequency and the bandwidth, the F / V converter circuit 8a
A voltage signal in a frequency band required by the voltage signal output from 1 can be output from the output terminal of the operational amplifier A3. For example, based on the frequency of the impact sound output from the microphone processing circuit 5d1, the center frequency is set to about 33.3H.
By setting the z and the bandwidth to about 20 to 50 Hz and outputting a voltage signal of a frequency in the range, the impact detection can be detected more accurately. Further, when a voltage signal in a frequency band not affected by the PWM control signal output from the PWM circuit 3 is output, the impact detection can be made more accurate and the tightening torque accuracy can be improved.

The comparator 8a3 includes a comparator Co5 connecting the output terminal of the operational amplifier A3 of the band-pass filter circuit 8a2 to the inverting input terminal, a reference power supply E2 connecting the positive terminal to the non-inverting input terminal of the comparator Co5, and grounding the negative terminal. Consisting of The voltage value of the voltage signal output through the band-pass filter circuit 8a is determined by the comparator Co5.
Is compared with the reference voltage value of the reference power source E2. If the reference voltage value is smaller than the reference voltage value, it is determined that a hit has occurred, and a rectangular wave voltage signal is output to the input terminal P of the microcomputer 4.

Incidentally, a frequency generator 5b may be used instead of the pulse generator 8. further,
The processing circuit for the battery voltage detection circuit may include a band-pass filter circuit 8a2.

[0048]

According to the first aspect of the present invention, in an impact rotary tool for applying a rotational force to an output shaft by hitting an output shaft by a hammer rotationally driven by a motor, a plurality of types of different fluctuations caused by the impact of the hammer are reduced. A plurality of detection means for detecting each type and outputting a detection signal,
A processing circuit that determines a blow individually from the detection signals of the plurality of detection means and outputs a blow detection signal, and counts the number of times of the blow when it is determined that a blow is detected by a detection signal from at least one of the plurality of detection means. Control means for controlling the number of rotations of the hammer based on a change in the number of hits within a certain period of time. However, there is an effect that the impact can be accurately detected and the tightening torque accuracy can be improved.

According to a second aspect of the present invention, there is provided a battery for supplying electric power to the motor, wherein the plurality of detecting means detects a change in the voltage between both ends of the battery and outputs a detection signal;
Since the frequency generator outputs a detection signal having an amplitude substantially proportional to the number of rotations of the motor, the same effect as that of the first aspect of the invention can be obtained.

According to a third aspect of the present invention, there is provided a battery for supplying electric power to the motor, wherein the plurality of detecting means detects a change in the voltage between both ends of the battery and outputs a detection signal;
Since this is a microphone that detects a hitting sound of a hammer and outputs a detection signal, the same effect as that of the first aspect of the invention is achieved.

According to a fourth aspect of the present invention, the plurality of detecting means include a frequency generator for outputting a detection signal having an amplitude substantially proportional to the number of revolutions of the motor, and a microphone for detecting a hitting sound of a hammer and outputting the detection signal. It has the same effect as the first aspect of the invention.

According to a fifth aspect of the present invention, there is provided a battery for supplying electric power to the motor, wherein the plurality of detecting means include a frequency generator for outputting a detection signal having an amplitude substantially proportional to the rotation speed of the motor; A battery voltage detection circuit that detects a fluctuation and outputs a detection signal, and a microphone that detects a hitting sound of a hammer and outputs a detection signal, and includes a detection signal from a frequency generator and at least a microphone or a battery power detection circuit. The control circuit counts the number of hits when the processing circuit determines the hits at substantially the same time from the detection signal from any one of them, so that the same effect as the first aspect of the present invention is achieved.

According to a sixth aspect of the present invention, there is provided a driving circuit having a switching element for driving a motor, and a driving circuit comprising a PWM circuit.
And at least one of the plurality of detection means is a pulse generator that outputs a detection signal having a frequency substantially proportional to the rotation speed of the motor.
There is an effect that the distortion of the detection signal waveform caused by the WM control signal is prevented, the impact is detected more reliably, and the tightening torque accuracy can be further improved.

According to a seventh aspect of the present invention, the processing circuit includes a converter circuit for converting a detection signal output from the pulse generator into a voltage value substantially proportional to the frequency of the detection signal, and a conversion circuit for converting the converted voltage value to a reference voltage value. And a comparison circuit for discriminating the impact by comparing the voltage value approximately proportional to the frequency of the detection signal with the reference voltage value, thereby more reliably detecting the impact and further increasing the tightening torque accuracy. There is an effect that it can be improved.

In a preferred embodiment of the present invention, the processing circuit determines a strike by comparing the peak value of the detection signal with a reference voltage value and a peak hold circuit for detecting the peak value of the detection signal output from the frequency generator. Since the comparison circuit is provided, there is an effect that the impact can be more reliably detected by comparing the peak value of the detection signal with the reference voltage value, and the tightening torque accuracy can be further improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment.

FIG. 2 is a circuit diagram showing a processing circuit for the microphone of the above.

FIG. 3 is a waveform diagram showing a voltage signal inside a microphone processing circuit according to the first embodiment.

FIG. 4 is a configuration diagram showing a motor and a processing circuit for a frequency generator according to the first embodiment;

FIG. 5 is a circuit diagram showing a processing circuit for the frequency generator of the above.

6A is a waveform diagram of a detection signal, and FIG. 6B is a waveform diagram of a striking detection signal, showing a processing circuit for the frequency generator of the above.

FIG. 7 is a block diagram illustrating a battery and a battery voltage detection circuit according to the third embodiment.

FIG. 8 is a waveform chart showing a detection signal output from the battery voltage detection circuit according to the first embodiment.

FIG. 9 is a block diagram illustrating a processing circuit for a frequency generator according to a second embodiment.

FIG. 10 is a circuit diagram showing a processing circuit for the frequency generator of the above.

FIG. 11 is a waveform diagram showing a detection signal input to a processing circuit for the frequency generator of the above.

FIG. 12 is a configuration diagram of a motor and a pulse generator according to a third embodiment.

FIG. 13 is a front view showing the detection panel of the above.

FIG. 14 is a circuit diagram showing a processing circuit for the pulse generator of the above.

FIG. 15 is a waveform diagram showing a hit detection signal output from a processing circuit for the pulse generator of the above.

FIG. 16 is a waveform chart showing another impact detection signal output from the pulse generator processing circuit of the above.

17A is a waveform chart showing a detection signal output from the frequency generator of the first or second embodiment, and FIG. 17B is a waveform chart showing a PWM control signal output from the PWM circuit of the first or second embodiment; It is.

FIG. 18 is a block diagram illustrating a processing circuit for a pulse generator according to a fourth embodiment.

FIG. 19 is a circuit diagram showing a processing circuit for the pulse generator of the above.

FIG. 20 is a waveform chart showing a detection signal input to the F / V converter circuit of the above.

FIG. 21 is a configuration diagram showing a microphone attachment example of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor 2 Drive circuit 3 PWM circuit 4 Microcomputer 5 Strike detection circuit 5a Microphone 5b Frequency generator 5c Battery voltage detection circuit 5d Detection block 6 Battery 7 Power supply circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masayuki Amano 1048 Kadoma Kadoma, Osaka Pref. Matsushita Electric Works, Ltd. (72) Inventor Minoru Yoshida 1048 Kadoma Kadoma, Kadoma, Osaka Pref. Terms (reference) 3C038 AA01 BC04 CA01 CA05 CB02 CB06 CC01 EA01 EA02 EA03 EA06

Claims (8)

[Claims] 1. An impact rotary tool that applies rotational force to an output shaft by hitting an output shaft with a hammer driven to rotate by a motor, and detects and detects a plurality of different types of variations caused by the impact of the hammer. A plurality of detecting means for outputting a signal, a processing circuit for discriminating a blow from each of the detection signals of the plurality of detecting means, and outputting a hit detection signal; and a hitting circuit for detecting a hit from at least one of the plurality of detecting means. An impact rotary tool, comprising: control means for counting the number of impacts when determined, and controlling the number of revolutions of the hammer based on a change in the number of impacts within a predetermined time. 2. A battery voltage supply circuit, comprising: a battery for supplying power to a motor; a plurality of detection means for detecting a change in voltage across the battery and outputting a detection signal; The impact rotary tool according to claim 1, further comprising a frequency generator that outputs an amplitude detection signal. 3. A battery for supplying electric power to the motor, wherein the plurality of detecting means detects a change in voltage between both ends of the battery and outputs a detection signal, and detects a hitting sound by a hammer. The impact rotary tool according to claim 1, further comprising a microphone that outputs a detection signal. 4. The method according to claim 1, wherein the plurality of detecting means are a frequency generator that outputs a detection signal having an amplitude substantially proportional to the number of revolutions of the motor, and a microphone that detects a hitting sound of a hammer and outputs the detection signal. The impact rotary tool according to claim 1, wherein 5. A battery for supplying electric power to a motor, wherein the plurality of detecting means detects a change in a voltage between both ends of the battery, and a frequency generator for outputting a detection signal having an amplitude substantially proportional to the number of rotations of the motor. A battery voltage detection circuit that outputs a detection signal, and a microphone that detects a hitting sound of a hammer and outputs a detection signal, and a detection signal from a frequency generator, and at least one of a microphone and a battery power detection circuit. 2. The impact rotary tool according to claim 1, wherein the control circuit counts the number of hits when the processing circuit determines the hits substantially simultaneously from the detection signal. 6. A driving circuit including a switching element for driving a motor, and a PWM circuit for performing PWM control on the driving circuit, wherein at least one of the plurality of detection units includes:
2. A pulse generator for outputting a detection signal having a frequency substantially proportional to the number of rotations of the motor.
Impact rotary tool as described. 7. A processing circuit for converting a detection signal output from a pulse generator into a voltage value substantially proportional to the frequency of the detection signal, and a processing circuit for comparing the converted voltage value with a reference voltage value. 7. The impact rotary tool according to claim 6, further comprising: a comparison circuit for determining whether the rotation of the impact rotary tool is performed. 8. A processing circuit includes: a peak hold circuit that detects a peak value of a detection signal output from a frequency generator; and a comparison circuit that compares the peak value of the detection signal with a reference voltage value to determine whether a blow has occurred. The impact rotary tool according to any one of claims 2, 4, and 5, wherein