JPH05220673A - Auto shutoff device for hydraulic pulse wrench - Google Patents

Abstract

PURPOSE:To detect the oil pressure at generating a pulse which causes the generating torque of a torque wrench, and precisely manage the torque on the basis of this data. CONSTITUTION:An oil pressure pulse generated in a pulse generating mechanism 3 by the rotation of an air motor 1 is transmitted to a hydraulic cylinder 34 through a piston 33, a rod 36 and a piston 35. When a pressure sensor set in the hydraulic cylinder 34 detects the oil pressure pulse, and a directional control valve 7 is switched by this signal, a stopping directional control valve 9 and a stopping differential pressure valve 8 are successively switched to stop the air feed to the air motor 1, and the current carrying from a battery 61 to an electric control circuit 6 is interrupted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic shutoff mechanism for managing the torque of a spindle of a torque wrench.

[0002]

2. Description of the Related Art A torque wrench that uses an air motor as a power source has a shut-off function of stopping the rotation of a rotor when a bolt, a nut, or the like is seated at a predetermined torque. Conventionally, the auto shut-off device for exhibiting this function detects the stop or reversal of the rotor by the inertial body connected to the rotor, opens the air supply valve by this movement of the inertial body, and supplies air to the air timer, The air supply to the air motor is shut off within a certain period of time after sitting.

According to Japanese Utility Model Laid-Open No. 3-40076, the rotational output of an air motor is intermittently transmitted to a spindle.
Also, in a torque wrench equipped with a pulse generation mechanism that generates a hydraulic pressure pulse each time a rotational force is applied to the main shaft, the hydraulic pressure on the high pressure generation side of the mechanism is applied to the relief valve, and the hydraulic pressure is set under the spring pressure of the relief valve. There is known an automatic shutoff device in which a relief valve is opened when the set pressure value is exceeded, and the hydraulic pressure at that time opens the on-off valve to stop the rotation of the air motor.

[0004]

In the above-mentioned two conventional examples, the former can obtain a certain degree of torque accuracy, but in reality, the generated torque is monitored and the automatic shutoff device is operated by the generated torque. However, there is a problem that the torque accuracy is easily influenced by the performance of the torque wrench itself and working conditions.

In the latter case, the hydraulic pressure pulse is generated only in an extremely short time, so that the hydraulic pressure on the high pressure side is often not sufficiently transmitted as the tightening force for the bolts and nuts. Also, if the hydraulic pressure on the high pressure side becomes higher than the spring pressure of the relief valve, the air motor will stop.Therefore, only the lower limit value of the generated torque will be controlled, and variation in the performance of mechanical parts such as springs will increase the operating accuracy. There was a problem of making it unstable.

The present invention has been made in view of the above drawbacks and problems, and detects the hydraulic pressure at the time of pulse generation that is the source of the torque generated by the torque wrench, and based on that data, a more accurate torque is obtained. An object is to provide an automatic shutoff device for a hydraulic pulse wrench that can be managed.

[0007]

An automatic shutoff device for a hydraulic pulse wrench according to a first aspect of the present invention comprises a fluid pressure motor,
A fluid pressure circuit for controlling the fluid pressure motor, a pulse generation mechanism that intermittently transmits the rotation output of the fluid pressure motor to the spindle with generated hydraulic pulses, and applies a rotational force to the spindle, and a pulse generation mechanism. When the hydraulic pressure pulse exceeds the set pressure, the reading means of the hydraulic pulse generated in step 1 and the electric control means for comparing the hydraulic pulse read by the reading means with the set pressure and converting the result into an electric signal and outputting the electric signal. Shutoff means for stopping the supply of fluid to the fluid pressure motor by the output from the electric control means.

According to another aspect of the present invention, there is provided an automatic shutoff device for a hydraulic pulse wrench, wherein the electric control means is provided with a counting means for outputting a signal when the hydraulic pressure pulse exceeds a set pressure a set number of times. I am trying.

In the hydraulic pulse wrench automatic shut-off device according to the third aspect, the electric control means can set the lower limit value and the upper limit value of the set pressure, and the lower limit value is used for the control by the counting means. On the other hand, it is characterized in that the NG signal is output when the hydraulic pressure pulse exceeds the upper limit value of the set pressure.

According to another aspect of the automatic pulse wrench automatic shutoff device of the present invention, the reading means is a pressure sensor for detecting the fluid pressure transmitted by the thrust of the hydraulic pulse.

According to another aspect of the present invention, there is provided an automatic shutoff device for a hydraulic pulse wrench, wherein the reading means is a load cell that produces a compressive strain due to the fluid pressure transmitted by the thrust of the hydraulic pulse.

An automatic shutoff device for a hydraulic pulse wrench according to a sixth aspect of the present invention is characterized in that the power source of the electric control means is a battery built in a housing.

[0013]

According to the automatic shutoff device of the hydraulic pulse wrench of claim 1, the hydraulic pulse corresponding to the rotational force of the spindle read by the reading means is directly compared with the set pressure by the electric control means, and the hydraulic pulse is When the set pressure is exceeded, the output signal of the electric control means causes the shut-off means to stop the supply of the fluid to the fluid pressure motor, thereby stopping the rotation of the fluid pressure motor.

According to the automatic shutoff device of the hydraulic pulse wrench of the second aspect, the hydraulic pulse exceeding the set pressure by the electric control means is provided so that the tightening force is sufficiently transmitted from the main shaft to the bolts and nuts. The number of occurrences is monitored.

According to the automatic shutoff device of the hydraulic pulse wrench of the third aspect, the value of the hydraulic pulse becomes particularly large due to some condition other than the tightening force transmitted to the bolt and the nut. Sometimes it is possible to eliminate the effects of that situation.

According to the automatic shutoff device for the hydraulic pulse wrench of claim 4, the reading means can be constructed at low cost.

According to the automatic shutoff device of the hydraulic pulse wrench of claim 5, the reading means can be easily handled.

According to the automatic shutoff device of the hydraulic pulse wrench of the sixth aspect, since the battery is incorporated in the housing, it is not necessary to draw out the electric wiring for energizing the electric control circuit from the housing.

[0019]

1 is a block diagram of an auto shut-off device according to an embodiment of the present invention. 2, 3 and 4 show different examples of the electric control circuit (electric control means) used in the automatic shutoff device.

In FIG. 1, reference numeral 1 denotes an air motor, the rotation direction of which is reversed depending on the direction of the air flow. The air circuit 2 for controlling the air motor 1 includes an air source 21.
And an air supply valve 22, a rotation direction control valve 23, and air passages 24a to 24e connecting them, and the air passages 24d and 24e are connected to the two air supply and exhaust ports 11 and 11 of the air motor 1. A muffler 25 is connected to the air passage 24f. Reference numeral 3 is a pulse generating mechanism, and the pulse generating mechanism 3 itself is publicly known from, for example, Japanese Utility Model Laid-Open No. 3-40076 mentioned at the beginning, and therefore its detailed structure will not be described. The pulse generation mechanism 3 intermittently transmits the rotation output of the air motor 1 to the main shaft 4, and generates a hydraulic pulse corresponding to the rotation force every time the rotation force is applied to the main shaft 4. And hydraulic pulse transmission chamber 3
The piston 33 having a small diameter is provided at the axial center position of the upper lid 32 forming the hydraulic pressure pulse generating chamber 31.
Is the hydraulic cylinder 34 on the opposite side of the air motor 1.
Pistons 35 of both are arranged, and both pistons 3
3, 35 are connected by a transmission rod 36 arranged so as to pass through the center of rotation of the air motor 1. In the hydraulic chamber 37 of the hydraulic cylinder 34, a pressure sensor 5 which is an example of a reading unit of a hydraulic pulse generated in the high pressure chamber is provided. The hydraulic pulse read by the pressure sensor 5 is processed by the electric control circuit 6. A battery 61 built in the housing 10 is used as a power source of the electric control circuit 6. A switching valve 7 is a two-position solenoid valve provided with a solenoid 71 which is operated by an output signal from the electric control circuit 6. Further, 8 is a stop differential pressure valve, 9 is a stop switching valve, and these three valves 7, 8 and 9 constitute a shut-off means. That is, the stop switching valve 8 is interposed between the air passages 24c and 24d, and the air pressure of the air passage 24c acts on both ends, and the stop switching valve 9 is provided on one end side. Are connected via an air passage 81. 8
An exhaust port 2 is connected to the stop switching valve 9. Further, one end of the stop switching valve 9 is connected to the air passage 2 via the switching valve 7.
4d or check valve 72. Further, the electric control circuit 6 and the battery 61 are connected via a pressure switch 62. The pressure switch 62 has a function of maintaining the energized state when the air passage 24d is at a high pressure and interrupting the energization when the air passage 24d is at a low pressure.

The air supply valve 22, the rotation direction control valve 23,
The switching valve 7, the stop differential pressure valve 8, and the stop switching valve 9 are
It is composed of a two-position switching valve. In addition, all of the above-described components are housed in the housing 10 of the torque wrench except for a part of the air source 21 and the air passage 24a.

The electrical control circuit 6 shown in FIG.
Setting value (pressure value) set by 3 and pressure sensor 5
The comparator 65 for comparing the hydraulic pressure pulse detected by the amplifier with the value amplified by the amplification amplifier 64, and the lower limit value of the hydraulic pressure pulse (set by the setting switch 63) for the set number of times (set by the setting switch 63). And counting means 66 for outputting a signal for switching the communication state of the switching valve 7 when continuously exceeded.

The electrical control circuit 6 shown in FIG.
The data holding unit 67 and the A / D converter 6 of the value set in 3
8 and a comparison calculation unit 65.

The electric control circuit 6 shown in FIG. 4 is obtained by replacing the comparison operation section 65 shown in FIG. 3 with a microcomputer 69.

Next, the operating state of the auto shut-off device having the electric control circuit 6 shown in FIG. 2 will be described.

The air motor 1 is stopped when the air supply valve 22, the rotation direction control valve 23, the switching valve 7, the stop differential pressure valve 8 and the stop switching valve 9 are set to the positions shown in FIG. is doing. Therefore, no torque is generated.

When the air supply valve 22 is switched from this state, air flows from the air source 21 to the air passage 24a, the air supply valve 22, the air passage 24b, the rotation direction control valve 23, the air passage 24c, and the stop differential pressure valve 8. , And is supplied to the air motor 1 through the air passage 24d in this order. Further, the air discharged from the air motor 1 is discharged through the air passage 24e, the rotation direction control valve 23, the air passage 24f, and the muffler 25 in this order. In such an operating state, the air motor 1 rotates normally, and the rotation output of the air motor 1 is intermittently transmitted to the spindle 4 by the pulse generating mechanism 3. The hydraulic pressure pulse generated in the high pressure chamber of the pulse generation mechanism 3 pushes down the piston 33 in the hydraulic pressure pulse transmission chamber 31. As a result, the piston 35 is pushed down via the transmission rod 36, so that the pressure of the hydraulic cylinder 34 at that time, that is, the hydraulic pulse is read by the pressure sensor 5, and the read signal is input to the electric control circuit 6.

In the electric control circuit 6, the setting switch 63 sets the lower limit value and the upper limit value of the set value for pressure, and the set value for the number of times.

Therefore, the comparator 65 compares the set value for the pressure with the hydraulic pulse read by the pressure sensor 5. Then, while the hydraulic pressure pulse read by the pressure sensor 5 is smaller than the set lower limit value, the above operating state is maintained. Further, when the hydraulic pressure pulse value read by the pressure sensor 5 becomes larger than the set upper limit value, the operation at that time is determined to be NG, the operation is immediately stopped, and a message to that effect is displayed. When the number of continuous hydraulic pressure pulses read by the pressure sensor 5 is greater than the set lower limit value and is greater than the set number of times, this is detected and output by the counting means 66. Then, the solenoid 71 is excited to switch the switching valve 7, and thereby the switching valve 9 for switching is switched, so that one end of the differential pressure valve 8 for stopping is communicated with the exhaust port 82. As a result, the stop differential pressure valve 8 is switched and air supply to the air motor 1 is stopped (auto shutoff function). At the same time, the air passage 24d becomes low in pressure, the pressure switch 62 is turned off, and the electricity from the battery 61 is turned off. The power supply to the control circuit 6 is cut off.

According to such an auto shut-off function, even after the hydraulic pressure pulse reaches a predetermined value, the hydraulic pulse having that value is applied to the bolt and the nut for a predetermined number of times, so that they can be securely tightened. Like When a hydraulic pressure pulse exceeding the set upper limit value is generated, it is determined that the correct operation is not performed, the operation is stopped, and a message to that effect is displayed, so that the tightening reliability for the bolts and nuts is improved. Further, since the battery 61 housed in the housing 10 is used as the power source of the electric control circuit 6, it is possible to prevent the electric wiring from being a hindrance and impairing the workability or breaking the electric wiring.

Although the pressure sensor 5 for detecting the hydraulic pressure transmitted by the thrust of the hydraulic pressure pulse is used as the reading means in the above embodiment, the pressure sensor 5 is used.
Instead of, a load cell that causes compression strain due to the hydraulic pressure transmitted by the thrust of the hydraulic pulse may be used. The load cell is more advantageous in terms of mounting structure and handling, and the pressure sensor 5 is more advantageous in terms of price.

[0032]

According to the automatic shutoff device for a hydraulic pulse wrench of claim 1, the hydraulic pressure at the time of pulse generation, which is the source of the torque generated by the hydraulic pulse wrench, is detected and based on that data. Since torque control can be performed, there is an effect that more accurate torque management can be performed.

Particularly, according to the automatic shutoff device for the hydraulic pulse wrench of the second aspect, even after the hydraulic pressure pulse reaches the predetermined pressure value, the hydraulic pulse having the value or more is applied to the bolt or the nut several times. Because you will be able to
It becomes possible to perform more reliable tightening.

According to the automatic shut-off device for the hydraulic pulse wrench of claim 3, the bolts and nuts can be securely tightened to a predetermined tightening by eliminating the influence of any situation other than the tightening force transmitted to the bolts and nuts. It becomes possible to transmit power.

Further, according to the hydraulic pulse wrench automatic shutoff device of the fourth aspect, the reading means can be constructed at a low cost, and the hydraulic pulse wrench automatic shutoff device of the fifth aspect allows reading. The handling of the means becomes easy.

According to the hydraulic pulse wrench automatic shut-off device of the sixth aspect, it is possible to prevent a situation such as disconnection of electric wiring for energizing the electric control circuit.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an automatic shutoff device according to an embodiment of the present invention.

FIG. 2 is a block diagram of an electric control circuit used in the automatic shutoff device.

FIG. 3 is a block diagram of another electric control circuit used in the automatic shutoff device.

FIG. 4 is a block diagram of still another electric control circuit used in the automatic shutoff device.

[Explanation of symbols]

 1 Air Motor (Fluid Pressure Motor) 2 Air Circuit (Fluid Pressure Circuit) 3 Pulse Generation Mechanism 4 Spindle 5 Pressure Sensor (Hydraulic Pulse Reading Means) 6 Electric Control Circuit (Electric Control Means) 7 Switching Valve 8 Stopping Differential Pressure Valve ( Shut-off means) 9 Stop switching valve (shut-off means) 61 Battery 66 Counting means

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[Procedure amendment]

[Submission date] December 18, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a configuration diagram of an automatic shutoff device according to an embodiment of the present invention.

FIG. 2 is a block diagram of an electric control circuit used in the automatic shutoff device.

FIG. 3 is a block diagram of another electric control circuit used in the automatic shutoff device.

[Explanation of reference numerals] 1 air motor (fluid pressure motor) 2 air circuit (fluid pressure circuit) 3 pulse generation mechanism 4 spindle 5 pressure sensor (hydraulic pulse reading means) 6 electric control circuit (electric control means) 7 switching valve 8 Stop differential pressure valve (shut-off means) 9 Stop switching valve (shut-off means) 61 Battery 66 Counting means

Claims (6)

[Claims] 1. A fluid pressure motor, a fluid pressure circuit for controlling the fluid pressure motor, and a rotational output of the fluid pressure motor is intermittently transmitted to a main shaft by a generated hydraulic pulse, and a rotational force is applied to the main shaft. A pulse generating mechanism for giving, a reading means for the hydraulic pressure pulse generated by the pulse generating mechanism, an electric control means for comparing the hydraulic pressure pulse read by the reading means with a set pressure and converting the result into an electric signal for output. A shutoff means for stopping the supply of fluid to the fluid pressure motor by the output from the electric control means when the hydraulic pressure pulse exceeds a set pressure, and an automatic shutoff of a hydraulic pulse wrench characterized by the following: Off device. 2. An automatic shutoff for a hydraulic pulse wrench according to claim 1, wherein the electric control means is provided with counting means for outputting a signal when the hydraulic pressure pulse exceeds a set pressure a set number of times. Off device. 3. The electric control means can set a lower limit value and an upper limit value of the set pressure, and while the lower limit value is used for the control by the counting means, the hydraulic pulse exceeds the upper limit value of the set pressure. The automatic shutoff device for the hydraulic pulse wrench according to claim 2, wherein the automatic shutoff device is configured to output an NG signal at times. 4. The automatic shutoff of the hydraulic pulse wrench according to claim 1, wherein the reading means is a pressure sensor for detecting the fluid pressure transmitted by the thrust of the hydraulic pulse. apparatus. 5. The automatic shutoff of the hydraulic pulse wrench according to claim 1, 2 or 3, wherein the reading means is a load cell that produces a compressive strain due to the fluid pressure transmitted by the thrust of the hydraulic pulse. Off device. 6. The hydraulic pulse wrench auto according to claim 1, claim 2, claim 3, claim 4, or claim 5, wherein the power source of the electric control means is a battery built in the housing. Shut-off device.