JP2002321165A - Hand impact wrench - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hand impact wrench capable of measuring a screw rotation angle with necessary and sufficient precision even if a hand shake occurs to some degree. SOLUTION: The hand impact wrench which is so composed that a rotary member repeats the operation of applying a driving force on the side of a driven shaft after free running is provided with the first detecting means 71a, 81a, 81b which detect the information as to the rotation of the rotary member, the second detecting means 72, 82a, 82b which detect the information as to the rotation of the driven shaft, and a measuring means 13 which measures the rotation angle of the driven shaft with a hand shake angle subtracted on the basis of the information as to the rotation of the rotary member detected by the first detecting means, and the information as to the rotation of the driven shaft detected by the second detecting means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention eliminates the effects of camera shake when tightening or loosening screws such as bolts and nuts using a hand-held impact wrench such as an impact wrench or an oil pulse wrench. And a technique for measuring actual tightening angles and loosening angles.

[0002]

2. Description of the Related Art Conventionally, when a large number of screws such as bolts and nuts are to be tightened in an automobile assembly and maintenance shop, it is necessary to tighten all screws with a uniform tightening force. For this reason, Japanese Patent Publication No. 6-16990
As described in Japanese Patent Application Laid-Open Publication No. H10-270, a screw is tightened by rotating a rotating member that rotates with a drive shaft around a driven shaft and transmitting the rotational force of the rotating member to the driven shaft via a hammer. At the same time, a hand-held impact wrench has been developed that detects the tightening angle (screw rotation angle) of this screw by a detection rotating body that rotates integrally with the drive shaft and a detection sensor provided on a non-rotating portion of the wrench body. Have been.

In the hand-held impact wrench,
In order to detect the tightening angle of the screw by the detection rotating body and the detection sensor, the number of pulses R1 when the rotating member rebounds in the reverse rotation direction after colliding with the driven shaft via the hammer, and the number of pulses after rebounding is free. The number of pulses F1 in the normal rotation direction (tightening direction) from the time of running and colliding again until the application of the impact force is detected, and from these pulse numbers R1 and F1, the number of pulses corresponding to the screw rotation angle in one impact is detected. In the case of an impact wrench having a configuration in which the rotating member makes one impact per rotation, θ1 = F1− (number of pulses corresponding to 360 °) −R1 (Equation 1). Then, the number of pulses corresponding to the screw rotation angle is calculated for each impact, converted to an angle, and the drive shaft is stopped when the accumulated angle reaches a predetermined screw tightening angle.

An oil pulse wrench configured to transmit the rotational force of a rotating member to a driven shaft via oil has been developed as a hand-held impact wrench.

[0005]

However, in the conventional hand-held impact wrench as described above, the number of pulses at the time of rebound and the number of pulses at the time of normal rotation are detected, and the screw rotation angle is calculated from the equation (1) by using these. Since the equivalent pulse number θ1 is obtained, if a hand shake described later occurs by an operator operating the impact wrench during a period from the seating of the screw to a predetermined screw tightening angle, the hand shake angle is directly used as the body of the impact wrench. It is understood that a large error occurs in the screw tightening angle detected by the detection sensor provided on the side, and a tightening control method based on the screw rotation angle using a hand-held impact wrench has not spread.

[0006] The "camera shake" described in this specification refers to the following three cases. 1. When the screw center does not move or moves linearly, and the impact wrench rotates with respect to the screw center. 2. When the screw center rotates around a point other than the center point (for example, an automobile wheel mounting screw) and the impact wrench is translated by the screw. 3. When the screw center rotates about a point other than the center point, and the impact wrench rotates with respect to the screw center. However, a case where the center of the screw moves linearly and the impact wrench moves in parallel by being hooked by the screw is not included in the hand shake described in this specification.

If any of the following five camera shakes A to E occurs, the rotation angle of the screw is detected to be smaller than the net rotation angle. A. The above 1. The impact wrench rotates in the same direction as the screw tightening direction. B. 2 above. In the case of, the screw center rotates in the direction opposite to the screw tightening direction. C. 3 above. In the case above, the impact wrench rotates in the same direction as the screw tightening direction, and the screw center rotates in the opposite direction to the screw tightening direction. D. 3 above. In the above case, the screw center rotates in the same direction as the screw tightening direction, but the impact wrench rotates in the same direction as the screw tightening direction by more than the rotation angle. E. FIG. 3 above. In this case, the impact wrench rotates in the direction opposite to the screw tightening direction, but the screw center rotates in a direction opposite to the screw tightening direction by a larger angle than the rotation angle.

[0008] In addition to the inventions already filed by the applicant, no suitable method has been proposed for not only the tightening control but also the loosening control. Therefore, for example, if the nut is turned too much in the loosening direction, the nut comes off from the bolt, and if sand or the like on the floor or the ground adheres, there is a problem that proper tightening cannot be performed later. Also, if the power tool is not sufficiently loosened, it may not be possible to loosen it by hand later.In such a case, some tools must be used again. However, there is a problem that workability is poor. Alternatively, when loosening a screw in a work at a high place, there is a problem that an excessively loosened nut comes off from a bolt, and a person underneath is put at risk by the dropped nut.

[0009] The inventors of the present invention have a very short moment (millisecond order) in which the shock is actually applied by the shock wrench, so that the hand-shake angle that can occur in such a short time can be made very small. Obtaining the knowledge, based on such knowledge, even if some hand shake occurs, filed a method that can measure the screw rotation angle with sufficient accuracy as required, in the present invention, further improved It is intended to propose a tool capable of measuring with higher accuracy.

[0010]

According to a first aspect of the present invention, there is provided a hand-held impact wrench configured to repeat an operation of applying a striking force to a driven shaft after free running. Detecting means for detecting information about the rotation of the driven member, information about the rotation of the rotating member detected by the first detecting means, and second detection. Measuring means for measuring the rotation angle of the driven shaft, excluding the camera shake angle, based on the information on the rotation of the driven shaft detected by the means.

According to a second aspect, the measuring means calculates the camera shake angle based on the information on the rotation of the rotating member detected by the first detecting means, and the measuring means detects the camera shake angle by the second detecting means. The accumulated value of the rotation angle of the driven shaft is obtained from the information on the rotation of the driven shaft, and the accumulated value of the camera shake angle is subtracted from the accumulated value to obtain the rotation of the driven shaft from which the camera shake angle has been removed. Subtraction means for measuring the angle.

According to a third aspect of the present invention, the measuring means includes a deceleration period detecting means for detecting a deceleration period of the rotating member based on information on rotation of the rotating member detected by the first detecting means. Only during the detected deceleration period, the accumulated value of the rotation angle of the driven shaft is obtained from the information on the rotation of the driven shaft detected by the second detection means, and the rotation of the driven shaft from which the camera shake angle is removed is obtained. Calculating means for measuring the angle.

According to a fourth aspect of the present invention, the measuring means includes a camera-shake angle calculating means for calculating a camera-shake angle from the information on the rotation of the driven shaft detected by the second detecting means, and a rotation angle detected by the first detecting means. Subtraction means for measuring the rotation angle of the driven shaft from which the camera shake angle has been removed from the information on the rotation of the member and the camera shake angle. In a hand-held impact wrench configured to repeat an operation in which a rotating member applies a striking force to a driven shaft after free running, a second detecting means for detecting information on rotation of the driven shaft And accumulating the rotation angle of the driven shaft only during a period in which the rotation speed of the driven shaft detected by the second detection means or a change thereof is greater than a predetermined value,
Measuring means for measuring the rotation angle of the driven shaft from which the camera shake angle has been removed.

According to a sixth aspect of the present invention, there is provided a control means for stopping the striking force when the sum of the rotation angles of the driven shaft measured by the measuring means reaches a preset angle. In claim 7, the direction in which the impact force is generated is the tightening direction,
Alternatively, there is provided switching means for switching in the loosening direction. However, in the case of a right-handed screw, the tightening direction refers to the clockwise direction, and the loosening direction refers to the counterclockwise direction. In the case of a left-handed screw, it indicates the opposite rotation direction. Note that the information on the rotation of the rotating member detected by the first detecting means includes the rotation angle, the rotation speed (angular speed) of the rotating member,
This includes angular acceleration, deceleration start time, rotation direction, and change in rotation direction. The information on the rotation of the driven shaft detected by the second detection means includes the rotation angle, the rotation speed (angular speed), the angular acceleration, the deceleration start time, the rotation direction, and the change in the rotation direction of the driven shaft. Is included.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A hand-held impact wrench used in an embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a vertical sectional side view of a main part of an impact wrench which is a wrench which generates a rebound upon impact as an example of a hand-held impact wrench used in the present invention. In addition,
Impact wrench such as impact wrench and oil pulse wrench described below are all hand-held type.

In the drawing, 1 is an impact wrench used in the present invention, 2 is an air motor provided inside the impact wrench 1, 3 is a drive shaft of the air motor 2, 4
Is a rotary cylindrical member integrally connected to the front end of the drive shaft 3. The center portion of the disc-shaped rear wall plate 4a of the rotating cylindrical member is integrally connected to the drive shaft 3 by a fitting structure of square irregularities. The impact wrench 1 is one embodiment of the hand-held impact wrench described in the claims, and is a tool used for both tightening and loosening the screw. The rotating cylindrical member 4 is one embodiment of the rotating member described in the claims.

As is well known, the air motor 2 supplies compressed air from the outside through an air supply passage (not shown), and operates the operation lever 20 and the switching lever 21 so that the air motor 2 is driven rightward by the compressed air. Alternatively, it is configured to be rotated at a high speed to the left. As is well known, the rotational force of the rotary cylindrical member 4 that rotates integrally with the rotation of the drive shaft 3 of the air motor 2 is referred to as an anvil protruded forward through a striking force transmission mechanism 5 described later. By transmitting the power to the driven shaft 6, a screw attached to a socket body (not shown) attached to the tip of the driven shaft 6 is tightened. FIG.
The switching lever 21 and the switching valve 22 shown in (1) have a configuration corresponding to the switching means described in the claims.

The rear portion of the driven shaft 6 has a large-diameter body portion 6a.
The body portion 6 a is provided at the center of the rotary cylindrical member 4. The rotating cylindrical member 4 is configured to rotate around the body portion 6a of the driven shaft 6 and transmit the rotational force to the driven shaft 6 via the impact force transmitting mechanism 5 as described above. . The striking force transmitting mechanism 5 includes a striking protrusion 5a projecting inward at an appropriate position on the inner peripheral surface of the rotary cylindrical member 4, and a semicircular support groove 6b formed on the body portion 6a of the driven shaft 6. And an anvil piece 5b supported to be able to swing right and left. The anvil piece 5b is tilted in the left-right direction, and the striking projection 5a collides with one upward facing end face of the anvil piece 5b to rotate. The rotational force of the cylindrical member 4 is transmitted to the driven shaft 6 side.

As shown in FIG. 10, the anvil piece 5b is provided with a cam plate 5c at the tip thereof on the inner peripheral surface of the front end of the rotary cylindrical member 4, and a recess 5d having a constant arc length in the circumferential direction.
When it is positioned inside, it maintains a neutral posture in which it does not engage with the striking projection 5a, and has a tilted posture that collides with the striking projection 5a when moving out of the recess 5d while contacting the inner peripheral surface of the rotary cylindrical member 4. Become. The anvil piece 5b is provided in the body part 6a of the driven shaft 6 by an anvil piece pressing member 5.
e, a spring 5f and a spring receiving member 5g constantly apply a force in the direction of the neutral position, and the spring receiving member 5g is in contact with the inner peripheral cam surface 4b of the rotary cylindrical member 4. Further, on the inner peripheral surface of the rotary cylindrical member 4, the anvil piece 5 is provided on both sides of the striking projection 5a.
A recess 5h that allows b to tilt is formed. Since the structure of such an impact wrench is known, detailed description is omitted.

Further, in the embodiment of the invention, the description has been given of the configuration in which the rotary cylindrical member 4 generates one impact per rotation. However, the configuration in which the rotary cylinder member 4 generates two impacts per rotation may be used. It goes without saying that the present invention can be similarly applied to a hand-held impact wrench configured to generate three or more hits.

On the outer peripheral surface of the rear end of the rotary cylindrical member 4, a first detecting rotary body 71 composed of a gear body provided with a predetermined number of teeth 71a is integrally fixed. On the other hand, a pair of first detection sensors 81a made of a semiconductor magnetoresistive element are provided on the inner peripheral surface of the casing 1b, which is on the non-rotation side opposite to the first detection rotator 71, at a constant interval in the circumferential direction. 81b is attached. The rotation of the first detection rotator 71 is detected by the first detection sensors 81a and 81b, and the output signal is input to the input circuit 10 electrically connected to the first detection sensors 81a and 81b. I have.

The driven shaft 6 is integrally fixed with a second detecting rotator 72 formed of a gear having a predetermined number of teeth 72a. On the other hand, a pair of second detection sensors 82a made of a semiconductor magnetoresistive element are provided on the inner peripheral surface of the casing 1b, which is on the non-rotating side opposite to the second detection rotator 72, at a constant interval in the circumferential direction. 82b is attached.
Then, the rotation of the second detection rotator 72 is detected by the second detection sensor 8.
2a, 82b, the output signal of which is electrically connected to the second detection sensors 82a, 82b.
Is configured to be input.

The signals from the two sets of detection sensors (first detection sensors 81a and 81b and second detection sensors 82a and 82b) input to the input circuit 10 are further supplied to the amplifier 1
1. Input to the control circuit 13 via the waveform shaping unit 12. The control circuit 13 includes a central processing unit 131, a rotation angle signal output unit 132, a screw tightening completion detection unit 133, a screw loosening completion detection unit 134, and an electromagnetic valve control unit 135. The control signal from the electromagnetic valve control unit 135 Is the output circuit 17
Is connected to a solenoid valve 19 provided in a compressed air supply hose 18 via a solenoid valve. The control circuit 13
Has a configuration corresponding to the measuring means, the camera shake angle calculating means, the subtracting means, the deceleration period detecting means, and the calculating means described in the claims, and has the functions described in the claims. If so, it may be realized by software, hardware, or a mixture of both.

Here, the screw loosening completion detecting section 1 shown in FIG.
Reference numeral 34 is used when the impact wrench 1 is used for screw loosening control. The first detection rotator 7
1 and the first detection sensors 81a and 81b constitute one embodiment of the first detection means described in the claims, and the second detection rotator 72 and the second detection sensor 82
a, 82b.
One embodiment of the detecting means is constituted.

In the above configuration, the electric components from the input circuit 10 to the output circuit 17 are provided in a controller (not shown) provided outside the impact wrench. The solenoid valve 19 constitutes the control means described in the claims. Further, the controller and the solenoid valve 19 can be built in an impact wrench. The solenoid valve 19 and the solenoid valve control unit 135 are connected to the solenoid valve 1.
A compressed air supply stopping device other than 9 and a control unit suitable for it may be used.

A method for detecting the tightening angles of the bolts and nuts in the impact wrench configured as described above will be described below. First, the screw 9 to be fastened is mounted on the socket body attached to the tip of the driven shaft 6, and a predetermined screw tightening angle is input to the screw tightening completion detecting unit 133 in advance. Thereafter, when the solenoid valve 19 is opened and the operation lever 20 of the impact wrench is pressed to supply compressed air to the impact wrench, and the air motor 2 is rotated in the screw tightening direction (in the case of a right-hand screw, the clockwise rotation direction), the drive is started. The shaft 3 and the rotating cylindrical member 4 rotate integrally. Then, the rotation of the cam plate 5c causes the recess 5d.
The anvil piece 5b moves while contacting the inner peripheral surface of the rotary cylindrical member 4 from the above, the frictional resistance between the spring receiving member 5g and the inner peripheral cam surface 4b causes the rotary cylindrical member 4 and the driven shaft 6 to be seated. Rotate integrally to advance the screw 9 while rotating it at a high speed in the tightening direction.

While the screw 9 is rotating and moving forward, that is, until the screw 9 is seated on the bearing surface, almost no load is applied to the driven shaft 6 side, and the gear body that rotates integrally with the rotary cylindrical member 4. The first detecting rotator 71 is also rotated at a high speed in the tightening direction of the screw 9 so that the teeth 71a thereof become the first detecting sensors 81a and 81a.
b. At this time, the first detection sensor 8
A pulse signal having a waveform shifted in phase is generated by 1a and 81b, but this pulse signal is not used in the calculation for angle detection until the screw is seated.

When the driven shaft 6 rotates at a high speed integrally with the rotary cylindrical member 4 through the striking force transmitting mechanism 5 including the striking projection 5a and the anvil piece 5b, and the screw 9 is seated on the tightening seat, the driven shaft 6 is driven. When a resistance torque (load) is generated on the shaft 6 and the rotation of the driven shaft 6 rapidly approaches stop, the striking projection 5a collides with the anvil piece 5b, and the striking is started.

After the impact is completed, the elastic force of the spring 5f pressing the anvil piece 5b overcomes the engaging force between the impact projection 5a and the anvil piece 5b, and the engagement is released. The member 4 is the body 6 of the driven shaft 6
Free-run around a. During the free running, the rotating cylindrical member 4 is accelerated by the rotational driving force of the air motor 2, while the cam plate 5c contacts the inner peripheral surface of the rotating cylindrical member 4 and the anvil piece 5b as shown in FIGS. Is tilted, and after the rotating cylindrical member 4 is free running, the striking projection 5a is shockably engaged with the anvil piece 5b, and the striking force causes the driven cylindrical member 4 to rotate on the driven shaft 6.
To rotate the driven shaft 6 by a certain angle in the tightening direction.

The timing at which the rotary cylindrical member 4 starts hitting, that is, the timing at which deceleration starts, is the timing at which screw tightening starts (in FIG. 3A).
This is detected as described later based on the deceleration start time, which is one of the information on the rotation of the rotating cylindrical member detected based on the signals from the first detection sensors 81a and 81b.
Then, at this timing, counting of the rotation pulse of the driven shaft 6 output from the second detection sensor is started ((B) in FIG. 3).

At the moment when the driven shaft 6 has been rotated in the tightening direction by a certain angle by the impact force of the impact projection 5a when the screw 9 is tightened, the rotating cylindrical member 4 rebounds in the direction opposite to the tightening direction. , The rotation direction is reversed (Fig. 3
(A)). The timing at which the driven shaft 6 has finished rotating in the tightening direction, that is, the timing at which the tightening in this impact is completed (FIG. 3B) is the timing at which the deceleration of the rotary cylindrical member 4 is completed (FIG. 3A). ) And the timing (of FIG. 3A) at which the rotation direction of the rotating cylindrical member 4 changes. This timing is detected based on a change in the rotation direction, which is one of the information on the rotation of the rotary cylindrical member 4 detected based on the signals from the first detection sensors 81a and 81b.

The deceleration period due to the impact of the rotating cylindrical member (FIG. 3
The rotation pulse of the driven shaft 6 output from the second detection sensor in (A)) is counted (period in FIG. 3B). After a certain angle rebound (of FIG. 3A), the rotating cylindrical member 4 is free running again in the tightening direction by the rotational driving force of the air motor 2 (FIG. 3A).
') Of (A). After the free running of the rotary cylindrical member 4, the striking projection 5a is impactedly engaged with the anvil piece 5b, and the driven shaft 6 is further rotated by a certain angle in the tightening direction by the striking force. Also at that time, similarly to the previous impact, between the timing of starting the tightening and the timing of ending the fastening, that is, the rotating cylindrical member 4 at the time of the impact.
The rotation pulses of the driven shaft 6 output from the second detection sensor during the deceleration period ('in FIG. 3A) are counted and added to the previous count value. The tightening is performed by repeating such an operation.

As described above, by accumulating the rotation pulse obtained from the second detection sensor only during the deceleration period of the rotary cylindrical member 4 at the time of hitting, the actual cumulative angle of the tightening angle of the screw is detected. When the cumulative angle reaches a predetermined screw tightening angle set in advance, a screw tightening completion signal is output from the screw tightening completion detecting unit 133, and the solenoid valve control unit 135 operates to automatically supply compressed air. And the tightening of the screw 9 is completed.

In the above, the timing of the start of deceleration at the time of impact and the timing of the end of deceleration, that is, the timing of a change in the rotation direction, are detected based on the information on the rotation of the rotary cylindrical member. Is configured to integrate the rotation pulses from the first detection sensor 8.
The number of camera shake pulses is detected from the information on the rotation of the rotary cylindrical member detected in 1a and 81b, and the second detection sensor 82
The actual number of tightening pulses excluding the influence of camera shake may be obtained by subtracting the number of camera shake pulses from the number of rotation pulses of the driven shaft 6 detected at a and 82b.

As shown in FIG. 4, from the information on the rotation of the rotating cylindrical member detected by the first detection sensors 81a and 81b, a period of free running of the rotating cylindrical member, a period of deceleration by impact, a period of rebound, Can be determined. A method of detecting the number of camera shake pulses in this method will be described below. As shown in FIGS. 5 and 6, during one cycle from the end of the impact to the end of the next impact, the number of pulses detected and derived corresponding to the rotation angle of the rotating cylindrical member corresponds to the rotation angle in the tightening direction. The number of pulses (Rp) corresponding to the rebound angle
The number of pulses obtained by subtracting p) is the sum of a design pulse number (Pdp) described later, a pulse number (ΔHp) corresponding to a screw tightening angle, and a pulse number (hp) due to camera shake. However, the design pulse number represented by Pdp is
In this case, a wrench having a configuration in which the rotating cylindrical member 4 hits once per rotation is shown, and the number of pulses is equivalent to 360 °.

Therefore, the number of camera shake pulses in this cycle can be obtained by the following equation (2). hp = (Fp−Rp) −Pdp−ΔHp (Equation 2) The above design pulse number is an eigenvalue determined with respect to the impact wrench, and is configured to generate m impacts each time the rotary cylindrical member makes one rotation. 360 ° for wrench
/ M is the number of pulses corresponding to the angle. In other words, if the wrench has a configuration in which the rotary cylindrical member 4 hits once per rotation, the number of pulses is equivalent to 360 °. If the wrench has a configuration in which the rotary cylinder member 4 hits twice per rotation, the pulse number is 180 °. The corresponding number of pulses.

5 and 6, from the time point P1 to the time point P2,
Also, from the time point P5 to the time point P6, a state is shown in which the rotating cylindrical member 4 is rotating integrally with the driven shaft 6 while decelerating. Therefore, the cumulative total of the number of camera shake pulses from the start of the first hitting cycle after the seating of the screw (that is, the occurrence of the first rebound) to the end of the k-th hitting cycle is expressed by the following equation.
As shown in the figure, in the rotation of the rotary cylindrical member, the number of pulses corresponding to the screw tightening angle (Rp) is obtained by subtracting the total number of pulses (Rp) in the opposite direction from the total number of pulses (Fp) in the tightening direction. ΔHp) and the total number of design pulses (Pdp) up to the end of the k-th impact (= design pulse number × number of impacts k) can be calculated. Σhp = (ΣFp-ΣRp) -Σ (Pdp) -Σ (ΔHp) (Equation 3)

Therefore, using the pulse from the first detection sensor, the number of camera shake pulses up to the end of the k-th impact cycle calculated by the equation 3 is calculated based on the driven shaft output from the second detection sensor during this period. By subtracting from the total number of rotation pulses (FIG. 4B), the actual number of tightening pulses from which the influence of camera shake has been eliminated can be obtained. When the angle according to the pulse number reaches a predetermined screw tightening angle set in advance, a screw tightening completion signal is output from the screw tightening completion detecting unit 133,
The solenoid valve control section 135 is activated, the supply of compressed air is automatically stopped, and the tightening of the screw 9 is completed.

As shown in FIGS. 4A and 4B, a period excluding a period of deceleration of the rotary cylindrical member 4 due to impact, that is, a period including a period from rebound to free running (FIG. 4A) At this time, it can be determined that the rotation pulse of the driven shaft output from the second detection sensor is a camera shake pulse, and this pulse is counted. The camera shake can also be obtained by subtracting the number of camera shake pulses detected by this method until the end of the k-th impact cycle from the total number of rotation pulses (FIG. 4B) output from the second detection sensor during this period. Can be obtained the actual number of tightening pulses from which the effect of (1) is eliminated.

In the above two methods, the accumulated value of the number of camera shake pulses from the start of the first striking cycle after the seating of the screw to the end of the k-th striking cycle is calculated based on the driven shaft during this period. The number of rotation pulses was subtracted from the total number of rotation pulses, but the number of hand shake pulses was subtracted from the number of rotation pulses of the driven shaft for each impact cycle, and the screw rotation angle was calculated. There is no problem even if a method of detecting a typical tightening angle is used.

In the following, the first detection sensor 81
FIGS. 13 to 13 show the outline of the procedure for detecting the rotation angle, the rotation speed, the deceleration start time, the rotation direction, and the change in the rotation direction, which are information relating to the rotation of the rotary cylindrical member detected in steps a and b.
A specific description will be given based on FIG. First detection sensor 8
1a, 81b, one pulse is detected each time one tooth of the first detection rotating body 71 that rotates integrally with the rotary cylindrical member 4 passes, and the number of pulses is accumulated by accumulating the pulses. The rotation angle of the rotary cylindrical member 4 corresponding to the rotation angle is detected. The rotation speed of the rotary cylindrical member 4 is detected from the number of passing teeth per unit time. 13A to 18, (a) shows the rotating cylindrical member 4.
(B) is an explanatory diagram of the tightening angle of the screw 9, and (c) is a diagram showing a change over time of the rotational speed of the rotary cylindrical member 4 and the tightening angle of the screw 9 for each impact. It is.
Also, the case where the screw 9 is tightened rightward is shown.

FIG. 13 is a view showing a state in which the rotating cylindrical member 4 is free-running. At this time, the rotating cylindrical member 4 is connected to the driven shaft 6 by the striking force transmitting mechanism 5 comprising the striking projection 5a and the anvil piece 5b. The rotational force of the rotating cylindrical member 4 is not transmitted, and the rotating cylindrical member 4 performs free running in the right direction while accelerating, as shown by the upward-sloping line in FIG. 13C and FIG.

The first detection sensors 81a and 81b are mutually
Since it is configured to output pulse signals having a phase difference of 90 degrees, as shown in FIG. 19, the waveforms of these pulse signals are such that the first detection rotator 71 rotates in the screw tightening direction (clockwise direction). If it is rotating, one of the detection sensors 8
From 1a, a pulse signal having a waveform advanced by 90 degrees from the other detection sensor 81b is output. Conversely, when the first detection rotator 71 rebounds in the counterclockwise direction together with the rotary cylindrical member 4 after the impact projection 5a collides with the anvil piece 5b and strikes, the first detection sensors 81a, 81b
The phase of the signal from is inverted. That is, the other detection sensor 81b outputs a pulse signal having a waveform advanced by 90 degrees from the phase of the one detection sensor 81a.

When the first detection rotator 71 is rotating in the tightening direction (right rotation direction), when the output waveform from the other detection sensor 81b is an up-edge (↑), the signal from one detection sensor 81a is output. Becomes high level (H), and becomes low level (L) when rotating in the rebound direction (left rotation direction). The detection signal indicating the rotation direction is denoted by Q0, and its waveform (H) or (L) holds a high level or a low level until the rotation direction changes. On the other hand, the signal Q1 holds a state completely opposite to that of the signal Q0. The central processing unit 131 is configured to detect a pulse signal in each direction while determining the tightening direction (right rotation direction) or the rebound direction (left rotation direction) based on the signal Q0 or the signal Q1. Therefore, free running is detected by a pulse signal (right pulse signal) in the normal rotation direction (tightening direction).

Next, after the rotating cylindrical member 4 is free running, as shown in FIG. 14 (c), at the moment when the striking projection 5a collides with the anvil piece 5b, the rotating speed of the rotating cylindrical member 4 becomes maximum. Then, the tightening of the screw 9 in this impact is started. At the time of this tightening, the driven shaft 6 rotating in the tightening direction via the impact force transmitting mechanism 5 consumes energy for tightening the screw 9.
As shown in FIG. 16 (c) and FIG. 19, the rotating cylindrical member 4 is decelerated from the above-mentioned maximum speed as shown by the right-downward line and tightened once, and then as shown in FIG. The member 4 rebounds leftward.

As shown in FIG. 19, the first detecting sensor 8 detects the time when the deceleration is started from the maximum speed.
The detection is performed by detecting the rotation state of the first detection rotator 71 by 1a and 81b. That is, the rotating cylindrical member 4
As you accelerate during free running,
The width of the pulse signal detected by the first detection sensors 81a and 81b gradually narrows, and becomes the minimum width at the moment when the impact protrusion 5a collides with the anvil piece 5b. End (rebound start)
Up to the right, the width of the pulse signal gradually increases. The pulse whose width gradually decreases and the pulse whose width gradually increases are output from the first detection sensors 81a and 81b and detected as the right pulse signal in the central processing unit 131 as described above, and the minimum pulse width is set. The point in time at which this occurs is determined to be the tightening start point of the screw 9 for this impact (the point in time at which deceleration of the rotating cylindrical member starts). Incidentally, this time can be set as the timing to start counting the rotation pulses of the driven shaft 6 output from the second detection sensor.

After the deceleration start time of the rotary cylindrical member 4 is detected in this way, the rotation angle of the first detection rotator 71 during the deceleration, in other words, from the start of deceleration to the end of impact, is determined by the first angle. It can be detected by the detection sensors 81a and 81b. Next, as described above, the rotating cylindrical member 4 rebounds in the left rotation direction. At the start of the rebound, the rotation direction of the rotating cylindrical member 4 changes from right rotation to left rotation. This time can be set as the timing to stop counting the rotation pulse of the driven shaft output from the second detection sensor.

As shown in FIG. 16, the speed of the rebound of the rotary cylindrical member 4 is gradually reduced and then stopped.
Again, the rotational direction of the rotary cylindrical member 4 is changed to the right by the rotational force from the air motor 2, and the rotary cylindrical member 4 runs free while accelerating as shown in FIG. Then, the striking projection 5a collides again with the anvil piece 5b, and as shown in FIG. 18, the rotational speed of the rotary cylindrical member 4 is reduced from the moment of the collision, and during the deceleration from the start of the deceleration to the end of the striking. Is detected by the first detection rotator 71 and the first detection sensors 81a and 81b in the same manner as described above.

After that, similarly, after the rotating cylindrical member 4 is free running, every time the rotating member 4 is decelerated by the impact, the timing of the start of the deceleration and the timing of the end of the impact can be detected. In this way, it is possible to detect the timing of the start of deceleration due to the impact (end of free running) and the timing of the end of deceleration due to the end of the impact (start of rebound) in FIGS. 3 and 4.

The method for obtaining the screw rotation angle described in "Impact wrench tightening force control device" by Japanese Patent Publication No. 6-16990 is a method capable of obtaining an accurate screw rotation angle (tightening angle). However, this is based on the premise that the hand-held impact wrench is fixed (there is no camera shake). If a camera shake occurs, the angle is added to or subtracted from the detected angle, and an accurate screw tightening angle cannot be obtained. However, if the impact wrench is fixed,
Regardless of the number of hits, the error is less than the resolution of the detection sensor, and high detection accuracy can be obtained. In FIG.
9 shows a hitting cycle of the rotating cylindrical member when there is no camera shake. Here, a case where the right screw is tightened will be described as an example. It is to be noted that a pulse signal is detected by the detection sensor, and the pulse signal is converted into an angle to perform control. However, in this description, an angle will be used for easy understanding. The pulse number and the angle have a one-to-one proportional relationship, and there is no problem even if the description is made based on the angle. Further, an example of an impact wrench having a configuration in which the rotating cylindrical member performs one impact per rotation will be described.

Table 1 shows the description of the movement of the rotating cylindrical member in each step in the hitting cycle shown in FIG. 23 and the rotation angle. The formula for calculating the screw rotation angle described in “Tightening force control device for impact wrench” of Japanese Patent Publication No. 6-16990 is shown as the following formula 4. ΣHn = Σ (Fn-Rn-P360) (Equation 4)

[Table 1]

Here, the concept of the ground as a stationary portion serving as a reference when detecting the screw rotation angle will be described. When determining the angle of rotation of the screw, it must be an absolute angle with respect to the member to be fastened. However, in the case of a hand-held impact wrench, the rotating cylindrical member can freely rotate with respect to the member to be fastened, and the casing in which the first detection sensor is attached can also rotate with respect to the member to be fastened. Although the mutual angle between the rotating cylindrical member and the casing can be detected, the rotation angle with respect to the member to be fastened cannot be detected.

In the screw tightening process using an impact wrench, the time required for the screw to rotate due to the impact is instantaneous.
At other times, the screw is stationary. The same applies to the driven shaft connected to the screw via the socket body. The driven shaft is stationary except at the moment of hitting, and is considered to function as the ground described above. Therefore, by detecting the rotation angle of the casing while the driven shaft is stationary using the second detection sensor that detects the movement of the driven shaft, the shake angle of the impact wrench can be detected.
In this way, if an accurate camera shake angle can be detected, the camera shake angle can be calculated from the screw rotation angle detected by the method described in `` Impact wrench tightening force control device '' in Japanese Patent Publication No. 6-16990. By subtracting, an accurate screw rotation angle can be obtained.

Next, a description will be given with reference to actual measurement data at the time of actual hitting. When the impact wrench is fixed,
It is assumed that Fn = 376 ° and Rn = 10 ° are detected with respect to Fn and Rn in the hitting cycle shown in Table 1 and FIG. 23 in the screw tightening in a state without camera shake. 1. Calculation of the screw rotation angle in the absence of camera shake by the method described in “Tightening force control device for impact wrench” in Japanese Patent Publication No. 6-16990. According to Equation 4, the screw rotation angle (tightening angle) in this impact cycle is: Hn = Fn-Rn-P360 = 376 ° -10 ° -360 ° = 6
°, indicating that the screw has been tightened by 6 °.

2. When camera shake is added. It is assumed that the above tightening is accompanied by a hand shake in which the impact wrench rotates clockwise (at the same direction as the screw tightening direction) at a speed of 180 ° / sec. In this case, as described above, the screw rotation angle is detected to be smaller than the net rotation angle. For example, since the time required for one impact cycle of a small impact wrench is about 50 milliseconds, 180 ° × 0.05 =
9 ° camera shake will be added. However, it is assumed that the camera shake speed does not change during this cycle and is constant.

Table 2 shows the time ratio of each step in each cycle in the actual hitting. FIG. 24 shows the angles at which the camera shake is added in each step when camera shake occurs, and Table 3 shows the description of each symbol. Table 4 shows the time ratio, the camera shake angle, and the apparent angle at which the camera shake is added in each step in the tenth hit cycle.

[Table 2]

[Table 3]

[Table 4]

When the screw rotation angle is calculated by the method described in Japanese Patent Publication No. 6-16990 "Control device for tightening force of impact wrench" in the state where the camera shake is added, Fn and Rn in Expression 4 are used instead. Therefore, * Fn and * Rn to which camera shake is added are used, and the calculation formula shown in Expression 5 is obtained. Σ * Hn = Σ (* Fn− * Rn−P360) (Equation 5) Then, the calculation result is as follows: * Fn− * Rn−P360 = 368.5831 ° −11.5831 ° −360 ° = −3.0000 ° Means that the screw rotation angle is minus,
That is, the screw is erroneously detected as not being tightened but being loosened.

3. Camera shake detection and method of removing it Camera shake can be detected by detecting the rotation angle of the driven shaft while the screw is stationary. During the period in which the screw is stationary, as shown in FIG. 25A, the impact start time T2 from the start time T1n of the rebound of the rotating cylindrical member.
n. As shown in FIGS. 25A and 25B, the camera shake angle ± h in this camera shake detection period in one cycle is 99.02% of the camera shake angle 9 ° in one cycle.
(That is, the sum of the steps A, B, and C in the time ratios shown in Table 4), and ± h = −9 ° × (99.02 / 100) = − 8.9118 °.

This camera shake angle is obtained by improving equation 4 based on the “impact wrench tightening force control device” of Japanese Patent Publication No. 6-16990, and formula 6 式 * Hn = Σ (* Fn- *) proposed in the present invention. Rn−P360− (± h)) (Equation 6): * Hn = * Fn− * Rn−P360− (± h) = 368.5831 ° −11.5831 ° −360 ° − (− 8.9118 °) = 5.9118 °. Here, when compared with 6 ° which is the actual screw rotation angle in the impact cycle, a slight error occurs.
This is because, in the period up to 3n, the detection of the camera shake angle and the correction using the same are not performed. However, the step of performing the impact (the step D) is an extremely short time of about 1% of the impact cycle, and an error occurring within that time is considered to be within a range in which there is no problem in the screw tightening accuracy.

In the above description, the screw rotation angle and the camera shake angle during the camera shake detection period are calculated by simulating the simulation. In addition, in order to facilitate the understanding of the explanation, the actual time of the process B and the time ratio in one cycle of the process were obtained by analyzing the actual data. It is preferable that the detection is performed collectively without dividing the time of the subsequent step C. In addition, it is preferable to use the following method for detecting the camera shake angle.

That is, the detection of the camera shake angle in the practical device is performed by using the first detection sensor, the rotating cylinder member, and the start time T1n (start of rebound) and the end time T2n (start of impact) of the camera shake detection period. Using the first detection rotator that moves together, using the method described above, the camera shake angle within this period is detected by the second detection rotator and the second detection sensor, and the rotation angle of the rotary cylindrical member is used. * Fn,
* Rn is detected by the first detection rotator and the first detection sensor, and these are substituted into Equation 6 to obtain the screw rotation angle. In the above description, the rebound angle from the right rotation angle of the rotating cylindrical member and 360 °
And the camera shake angle were subtracted to determine the screw rotation angle, and the method of accumulating it was explained. Separately, k was calculated from the start of the first impact cycle after the screw was seated.
The total of the camera shake angle until the end of the second impact cycle, the total of the right rotation angle of the rotating cylindrical member, the total of the rebound angle, and the total of k times of the angle corresponding to the design pulse number,
, And a method of determining the screw rotation angle using them may be used as long as the configuration of claim 4 is used.

Next, the influence of play at the mechanically connected portion will be examined. For example, in the case shown in FIG.
The effect of play at the joint between the driven shaft 6 of the impact wrench 1 and the socket body (denoted as "play A") and the play at the joint between the socket body and the hexagonal portion of the head of the screw (" Play B ").) In general, the influence of play in the above two parts is negligible, but in order to perform the tightening control with higher accuracy, the following measures can be added.

In the case of the impact wrench shown in FIG. 1, the spring 5f shown in FIG. 11 is made stronger than the conventional one to push the inner cam surface 4b of the rotary cylindrical member 4 of the spring receiving member 5g. It is advisable to increase the power and thereby reduce the occurrence of play. That is, when the rotating cylindrical member 4 rebounds, the driven shaft also slightly reverses by the amount of the "play A" and "play B". Since the spring 5f is made stronger than the conventional spring as described above, a larger frictional force is generated during free running of the rotary cylindrical member 4 shown in FIG. Attached to the cylindrical member 4,
A rotational force in the clockwise direction is also applied to the driven shaft 6, and the "play A" portion is shifted toward the clockwise direction as shown in FIG. At the same time, the "play B" portion is also shifted rightward in the clockwise direction as shown in FIG. Therefore, at the time of hitting by the rotating cylindrical member 4, the "play A" and "play B" are eliminated, and the error between the rotation angle of the driven shaft 6 and the screw rotation angle is eliminated. In this way, by making the spring 5f stronger than usual, it is possible to detect the rotation angle with higher accuracy. It should be noted that there may be little play by reducing the gap between the fitting portions of the irregularities in the above-mentioned "play A" and "play B" portions. Further, the above two methods for suppressing the occurrence of play can also be applied to an oil pulse wrench described below.

Next, an oil pulse wrench will be described with reference to FIG. 9 as another example of the hand-held impact wrench used in the present invention. Fig. 1
In the same manner as in the first embodiment, in addition to the conventional first detection sensors 81a and 81b, second detection sensors 82a and 82b for outputting a rotation pulse of the driven shaft 6A are provided. Note that the method of detecting the rotation pulse by these detection sensors is the same as the above-described method, and a description thereof is omitted.

The oil pulse wrench is an embodiment of the hand-held impact wrench described in the claims, and is a tool used for both tightening and loosening the screw. The oil cylinder 4A is one embodiment of the rotating member described in the claims. Also in the case of the oil pulse wrench configured as described above, it is possible to detect the rotation angle of the driven shaft from which the camera shake angle has been removed, similarly to the impact wrench described above.

Next, a description will be given of a hand-held impact wrench capable of detecting a tightening angle excluding the influence of camera shake using only the second detection sensor, with reference to FIG. In this case, the control circuit 13 accumulates the rotation angles of the driven shafts 6 and 6A only during the period when the rotation speed of the driven shafts 6 and 6A detected by the second detection sensor is greater than the predetermined value ω0. And a measuring unit for measuring the rotation angle of the driven shaft from which the camera shake angle has been removed.

That is, in the central processing unit 131, only when the rotation speed of the driven shaft detected by the second detection sensor is larger than the predetermined value ω0, the output of the driven shaft The rotation pulses are counted and accumulated. The screw tightening completion detecting section 133 outputs a control signal from the solenoid valve control section 135 when the accumulated value of the rotation pulse reaches a value corresponding to a predetermined tightening angle, and outputs an output circuit. 17 via solenoid valve 1
9 is closed to end the tightening.

As described above, camera shake is obtained by accumulating rotation pulses of the driven shaft output from the second detection sensor only during a period in which the rotation speed of the driven shaft detected by the second detection sensor is higher than a predetermined value. It is now possible to eliminate the effects of In other words, the rotational speed of the driven shaft due to impact is very high, but the rotational speed of the driven shaft due to camera shake is low, so the effect of camera shake is eliminated by eliminating rotation pulses during periods when the rotational speed is low. It became possible to do.

Next, a case where the screw is loosened using the impact wrench having the above-described configuration will be described with reference to FIG.
First, the socket body attached to the distal end of the driven shaft 6 is mounted on the screw 9 to be loosened, and a predetermined screw loosening angle θr is input to the screw loosening completion detecting unit 134 in advance. Thereafter, the solenoid valve 19 is opened, and the switching lever 21 of the impact wrench is operated to the loosening side to switch the switching valve 22.
0, the compressed air is supplied to the impact wrench, and the air motor 2 is rotated in the screw loosening direction (in the case of a right-handed screw, counterclockwise rotation). The driving force of the rotary cylindrical member 4 is transmitted to the driven shaft 6 by the impact force, and the driven shaft 6 is rotated in a loosening direction by a certain angle.
The rotation pulse based on the rotation of the driven shaft in the loosening direction at this time is detected by the second detection sensor.

The detected rotation pulse of the driven shaft is input to the control circuit 13. Then, in the central processing unit 131, the rotation pulse of the driven shaft detected by the second detection sensor is counted for each impact, and when the driving shaft is driven at a speed exceeding a predetermined rotation speed ωr, Count and accumulate rotation pulses. In this way, a rotation pulse that does not exceed the predetermined rotation speed ωr, such as a camera shake shown in a portion T of FIG. 8B, is eliminated.

The screw loosening completion detecting section 134 outputs a control signal from the solenoid valve control section 135 when the accumulated value of the rotation pulse reaches a value corresponding to a preset loosening angle θr. Then, the solenoid valve 19 is closed via the output circuit 17 to end the loosening. As described above, since the impact wrench is stopped at the preset screw loosening angle, the problem that the bolt or nut falls off can be solved. In the two methods using only the second detection means described above, a method of accumulating rotation pulses of the driven shaft only during a period in which the rotation speed of the driven shaft is higher than a predetermined value is used. On the other hand, the angular acceleration, which is a change per unit time of the rotation speed (angular velocity) of the driven shaft due to the impact, is very large, but the angular acceleration of the driven shaft due to camera shake is small. It is also possible to use a method of accumulating rotation pulses of the driven shaft only during a period larger than the value. In addition, the configuration of the impact wrench (the second detection sensor and the second detection rotator) described here is also applicable to a hand-held oil pulse wrench.

The first and second detecting means described in the claims of the hand-held impact wrench are not limited to the above-described structure, and the second detecting means is mounted on the driven shaft. The rotation of the socket body may be detected by a second detection sensor provided on the inner surface of the socket cover integrated with the casing on the non-rotating side. Also,
As shown in FIG. 20, each of the detecting means has a detecting rotator 7 'composed of a disc provided with slits or light reflectors at regular intervals in the circumferential direction, and a photo interrupter for detecting the number of passing slits or the number of light reflections. Set of light detection sensors 8
a ′, 8b ′ may be used.

As another embodiment of the first detecting rotator, as shown in FIG. 21, it may be provided integrally with the shaft end of the air motor. In addition to this, it is also possible to provide the rotary shaft at any position between the air motor and the rotating member as long as the rotary shaft rotates integrally with the air motor.

It is to be noted that an electric motor or an engine such as an internal combustion engine may be used in place of the air motor. Further, as the impact force transmission mechanism, an impact wrench having a configuration disclosed in JP-B-61-7908, US Pat. No. 2,285,638, U.S. Pat.
S.PAT2, 160, 150, US.PAT3, 661, 217, US.PAT3, 174, 597,
The present invention can also be applied to a striking force transmission mechanism used in an impact wrench having a clutch structure disclosed in US.PAT3,428,137 and US.PAT3,552,499. The present invention can be applied to a hand-held power screw tightening tool such as an impact wrench, an oil pulse wrench, and an impact driver.

[0076]

As described above, according to the first and second aspects of the present invention,
According to the third and fourth hand-held impact wrenches, the first detecting means for detecting information about the rotation of the rotating member, the second detecting means for detecting information about the rotation of the driven shaft, and the first detecting means Measuring means for measuring the rotation angle of the driven shaft, excluding the camera shake angle, based on the information about the rotation of the rotating member detected at the and the information about the rotation of the driven shaft detected by the second detection means, , The actual rotation angle of the driven shaft is measured, and accurate tightening or loosening of screws or the like can be performed.

According to the hand-held impact wrench of the present invention, the second detecting means for detecting information on the rotation of the driven shaft, and the rotational speed of the driven shaft detected by the second detecting means Or a measuring means for accumulating the rotation angle of the driven shaft only during a period in which the change is greater than a predetermined value and measuring the rotation angle of the driven shaft from which the camera shake angle has been removed. Without the need for detecting means, the actual rotation angle of the driven shaft can be measured, and accurate tightening or loosening of screws or the like can be performed.

According to the hand-held impact wrench of claim 6,
Control means for stopping the striking force when the sum of the rotation angles of the driven shaft, from which the camera shake angle has been removed, measured by the measuring means has reached a preset angle, is provided. By measuring the actual rotation angle, it was possible to prevent excessive tightening or loosening of screws and the like, and proper work was possible.

According to the hand-held impact wrench of claim 7,
Since the switching means for switching the direction of generation of the impact force to the tightening direction or the loosening direction is provided, the hand-held impact wrench having the above-mentioned effects can be easily switched to the tightening or loosening operation of screws or the like. .

[Brief description of the drawings]

FIG. 1 is a vertical side view of an impact wrench used in an embodiment of the present invention.

FIG. 2 is an explanatory diagram schematically showing a main part of FIG. 1;

FIG. 3 is an explanatory diagram illustrating an example of processing of a rotation pulse of a driven shaft in the impact wrench of FIG. 1;

FIG. 4 is an explanatory diagram illustrating another example of processing of a rotation pulse of a driven shaft in the impact wrench of FIG. 1;

FIG. 5 is a velocity diagram showing an example of a method for detecting camera shake in an impact wrench.

FIG. 6 is a diagram illustrating a rotating state of a rotating cylindrical member.

FIG. 7 is an explanatory diagram illustrating still another example of processing of a rotation pulse of a driven shaft in the impact wrench of FIG. 1;

FIG. 8 is an explanatory diagram in the case of loosening.

FIG. 9 is a vertical sectional side view of an example of an oil pulse wrench.

FIG. 10 is a vertical sectional front view of a cam plate portion for operating an anvil piece.

FIG. 11 is a vertical sectional front view of a striking force transmission mechanism during free running.

FIG. 12 is an operation state diagram of the cam plate.

FIG. 13 is an explanatory diagram of a speed during free running of the rotary cylindrical member provided with a hitting projection.

FIG. 14 is an explanatory diagram of the speed at the moment when the impact is started.

FIG. 15 is an explanatory view at the time of screw tightening.

FIG. 16 is an explanatory diagram of speed during rebound.

FIG. 17 is an explanatory diagram of speed when free running is performed again.

FIG. 18 is an explanatory view of a tightening angle at the time of tightening.

FIG. 19 is a diagram showing the relationship between the operation of the rotating cylindrical member and its pulse signal.

FIG. 20 is an explanatory diagram of another embodiment of the pulse detector.

FIG. 21 is an explanatory diagram of another embodiment of the first detection rotator.

FIG. 22 is an explanatory diagram in a case where occurrence of play is suppressed.

FIG. 23 is an explanatory diagram of a striking cycle of the rotating cylindrical member when there is no camera shake.

FIG. 24 is an explanatory diagram of a striking cycle of the rotating cylindrical member when there is camera shake.

FIG. 25 is an explanatory diagram of a striking cycle of the rotating cylindrical member when there is camera shake.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Impact wrench (hand-held impact wrench) 1b Casing 2 Air motor 3 Drive shaft 4 Rotating cylindrical member (rotating member) 5 Striking force transmission mechanism 5a Striking protrusion 5b Anvil piece 6 Driven shaft 71 First detected rotating body (first detection) Means 81a, 81b First detection sensor (first detection means) 72 Second detection rotating body (second detection means) 82a, 82b Second detection sensor (second detection means) 133 Screw tightening completion detection section 134 Screw loosening completion detector

Claims (7)

[Claims] In a hand-held impact wrench configured to repeat an operation in which a rotating member applies a striking force to a driven shaft after free running, first detecting means for detecting information related to rotation of the rotating member; A second detector for detecting information about the rotation of the driven shaft, information about the rotation of the rotating member detected by the first detector, and information about the rotation of the driven shaft detected by the second detector. Measuring means for measuring the rotation angle of the driven shaft excluding the camera shake angle based on the information. A measuring means for calculating a camera shake angle based on information on rotation of the rotating member detected by the first detecting means; and a driven shaft detected by the second detecting means. Obtain the accumulated value of the rotation angle of the driven shaft from the information on the rotation of the shaft, subtract the accumulated value of the camera shake angle from the accumulated value, and measure the rotation angle of the driven shaft from which the camera shake angle has been removed. 2. A hand-held impact wrench according to claim 1, further comprising subtraction means for performing the operation. 3. A deceleration period detecting means for detecting a deceleration period of the rotating member based on information on rotation of the rotating member detected by the first detecting means, and a deceleration period detected by the deceleration period detecting means. Only during the period, the accumulated value of the rotation angle of the driven shaft is obtained from the information on the rotation of the driven shaft detected by the second detection means, and the rotation angle of the driven shaft from which the camera shake angle is removed is measured. 2. A hand-held impact wrench according to claim 1, further comprising: a calculating means for performing the operation. A measuring means for calculating a camera shake angle from information about the rotation of the driven shaft detected by the second detecting means; and a rotation of the rotating member detected by the first detecting means. 2. The hand-held impact wrench according to claim 1, further comprising subtraction means for measuring a rotation angle of the driven shaft from which the camera shake angle has been removed from the information about the shake and the camera shake angle. 5. A hand-held impact wrench configured to repeat an operation in which a rotating member applies a striking force to a driven shaft after free running, a second detecting means for detecting information on rotation of the driven shaft. And the rotation speed of the driven shaft detected by the second detection means or the rotation angle of the driven shaft only during a period in which the change is greater than a predetermined value is accumulated, and the rotation of the driven shaft from which the camera shake angle is removed is calculated. A hand-held impact wrench, comprising: a measuring means for measuring a rotation angle. 6. A control means for stopping the striking force when the sum of the rotation angles of the driven shafts measured by the measuring means reaches a preset angle. The hand-held impact wrench according to any one of claims 1 to 5. 7. The hand-held impact wrench according to claim 1, further comprising switching means for switching a direction in which the impact force is generated to a tightening direction or a loosening direction.