JPS6231255Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a nut runner that automatically tightens screws using the rotational driving force of an air motor.

A nut runner has already been proposed in which an air motor is rotated by high-pressure air and the rotation is slowed down before screw tightening work is performed. However, since conventional nut runners do not have a pressure regulating function, they have the disadvantage that if there is a pressure fluctuation in the high-pressure air sent to the air motor, this will directly appear as a fluctuation in the tightening pressure. ,
There is a risk of insufficient tightening or over tightening.
In particular, in the case of a multi-shaft nut runner with several nut runners arranged in parallel, a piping configuration is used to supply air from one compressor to each nut runner via a distributor. If there is a problem with the nut runner and there is a difference in the air supply pressure to each nut runner, the tightening pressure will be different for each nut runner, or
Even if the distributor is normal, if only some of the nut runners are tightened first, air will be concentrated on the remaining nut runners and the air pressure will be considerably high, causing the tightening force of the later ones to be higher. A fluctuation occurs in which the tightening force becomes stronger than the previous one. In order to prevent such fluctuations in the tightening pressure, conventionally a pressure regulator was installed on the compressor side, but this system does not adjust the tightening pressure in the case of a single-shaft nut runner. Although it is possible to stabilize
It is not effective in the case of a multi-shaft nut runner as described above.

In view of these points, the present invention has a simple structure and incorporates a small pressure regulating valve into the nut runner itself.
To provide a nut runner that can always obtain a constant tightening pressure regardless of whether it is a single shaft or multi-shaft or the performance of a distributor.

The nut runner of the present invention will be described below with reference to the embodiments shown in the drawings. The nut runner 1 has an air motor 2, a reduction gear 3, and a pressure regulating valve 4. High pressure air is supplied to the air motor 2 from a compressor or the like through an air supply pipe 5, and the air motor 2 rotates at high speed. A speed reducer 3 is connected to the air motor 2, and the rotation of the air motor 2 is decelerated and transmitted to the main shaft 6 for screw tightening work. A socket is attached to the main shaft 6 as appropriate depending on the shape of the screw. A pressure regulating valve 4 is integrally attached to the rear end of the air motor 2, and air is supplied to the air motor 2 through the pressure regulating valve 4. The structure of the pressure regulating valve 4 is shown in FIGS. 2 and 3. 7 is a valve chamber that communicates with an air supply port 8, and an air supply pipe 5 is connected to this air supply port 8.
is connected. A valve body 9 is provided in the valve chamber 7 so as to be movable in the axial direction, and a spring 1 is attached to the valve body 9.
A restoring force in the valve closing direction due to 0 is applied.
Reference numeral 11 denotes a valve seat, in which a ventilation passage 12 is formed, and when the valve body 9 contacts the open end of this ventilation passage 12 and closes the open end, the pressure regulating valve 4 closes and the valve body closes. The valve opens when 9 leaves. 13 is air motor 2
This is a ventilation path leading to the valve seat 11, and is linked to the ventilation path 12 of the valve seat 11. In addition, a pressure gauge 1 is placed in the middle of this ventilation path 13.
4 is attached so that the pressure of the air sent to the air motor 2 can be measured.

An air chamber 15 is formed behind the valve seat 11, and a diaphragm 16 is attached to this air chamber 15, and the air chamber 15 is divided into a front chamber 15a and a rear chamber 15b by this diaphragm. . The front chamber 15a is communicated with the ventilation path 13 through the ventilation hole 17, and the air pressure in the front chamber 15a is equal to the air pressure in the ventilation path 13. Also, a spring 1 is provided in the rear chamber 15b.
8 is accommodated, and a pressing force from a spring 18 acts on the diaphragm 16. Further, the diaphragm 16 and the valve body 9 are integrally connected by a connecting rod 19, and when the diaphragm 16 moves, the valve body 9 also moves in conjunction. 20 is a reinforcing member attached to the center of the diaphragm 16. Reference numeral 21 denotes an adjustment device that adjusts the back pressing force acting on the diaphragm 16 by changing the strength of the spring 18, thereby adjusting the air pressure sent to the air motor 2. 22 is an adjustment dial, 2
3 is an adjustment bolt integrated with the dial, 24 is a nut screwed onto the bolt, and this nut 2
4 serves as a washer for the spring 18. Therefore, when the adjustment dial 22 is rotated, the screw 23 rotates in conjunction, and the nut 24 is prevented from rotating, so it moves in the axial direction.As a result, the distance between both ends of the spring 18 changes, and the diaphragm the spring pressure acting on 16;
That is, the back pressing force can be adjusted.

Next, the pressure regulating operation will be explained. First, ventilation path 1
When the pressure of the air sent to the air motor 2 through the air motor 2 is lower than the set value, the air pressure in the front chamber 15a is low, so the pressing force by the spring 18 prevails, and the diaphragm 16 is pushed by the spring 18 and As shown in the figure, it deforms toward the anterior chamber side. As a result, the connecting rod 19 and the valve body 9 are pushed to the left in the figure, the valve body 9 separates from the valve seat 11, and the valve becomes open, allowing high-pressure air supplied from the air supply port 8 to pass through the valve. The air motor 2 continues to rotate, and the screw tightening operation continues. Next, when the screw is seated, the rotation of the air motor 2 is suppressed by the reaction force, and as a result,
The air pressure in the ventilation path 13 and the front chamber 15a increases.
When the air pressure in the front chamber 15a reaches the set value, the diaphragm 16 is pushed to the right in the figure by overcoming the pressing force of the spring 18, resulting in the state shown in FIG. 2, and the valve body 9 is pushed by the spring 10. The air motor 2 comes into contact with the valve seat 11, the valve closes, and the air motor 2 stops. Note that the set value can be freely adjusted by rotating the dial 22.

In the illustrated example, a thin ventilation hole 25 is formed in the reinforcing member 20 attached to the center of the diaphragm 16, and the tip of the connecting rod 19 abuts on this ventilation hole 25 via an O-ring. For this reason, when the ends of the connecting rods 19 are in contact, the ventilation holes 25 are blocked, but when the connecting rods 19 are separated, the ventilation holes 25
5 opens. This is because when the pressure in the front chamber 15a becomes too high and the diaphragm 16 deforms significantly against the pressure of the spring 18, the air on the front chamber 15a side is diverted to the ventilation hole 25 and the hole 3 formed in the wall of the rear chamber 15b. This is to reduce the pressure on the front chamber 15a side by discharging the air through the front chamber 15a.

FIG. 4 shows the state in which multiple shafts are used, 26 is a nut runner mounting plate, 27 is a hanging member, 28 is a handle,
29 is a control device, 30 is an operating lever, 31 is an on-off operating valve, 32 is a distributor, and 33 is a socket.

As mentioned above, in the nut runner of this invention,
Each nut runner is equipped with a pressure regulating valve 4, and the tightening pressure can be adjusted for each nut runner.For example, when using multiple shafts, there may be a difference in the supply pressure to each nut runner, and the tightening pressure may vary until tightening is complete. The tightening pressure of all nut runners can be maintained at the specified set value even if there is a time difference between
Screw tightening work can be performed reliably and with high precision. Furthermore, since the pressure regulating valve is built into the nut runner in the present invention, the entire device can be made more compact and more convenient to handle than when the pressure regulating device is provided separately. .
Further, in the present invention, the diaphragm 16 is used in the pressure regulating valve 4, so the structure is simple and the operation is reliable. It should be noted that if a pressure gauge 14 is attached, the tightening pressure can be measured and confirmed, which is even more convenient.

[Brief explanation of the drawing]

The drawings show an embodiment of the nut runner of the present invention. Figure 1 is a partially sectional side view, Figure 2 is an enlarged sectional view of the main part when the pressure regulating valve is closed, and Figure 3 is when the pressure regulating valve is open. FIG. 4 is an enlarged sectional view of the main part in the valve state, and a side view showing the multi-shaft usage state. 1...nut runner, 2...air motor, 3
3...Reducer, 4...Pressure regulating valve, 5...Air supply pipe, 6...Work main shaft, 7...Valve chamber, 8...Air supply port, 9...Valve body, 10...Spring, 11 ……valve seat,
12, 13...Vent passage, 14...Pressure gauge, 15...
...air chamber, 15a...front chamber, 15b...rear chamber, 1
6...Diaphragm, 17...Vent hole, 18...
Spring, 19... Connection rod, 20... Center reinforcing member, 21... Adjustment device, 22... Adjustment dial,
23...adjustment bolt, 24...nut.

Claims (1)

[Claims for Utility Model Registration] 1. An air motor 2, a reducer 3 connected to the air motor 2, a main shaft 6 that tightens screws using the rotational power from the reducer 3, and an adjuster integrally attached to the air motor 2. The pressure regulating valve 4 has a valve body 9 that opens and closes the air supply passage to the air motor 2. This valve body 9 is connected to a diaphragm 16, and the valve body 9 is opened by the operation of the diaphragm 16. moves to open and close, applying air pressure to one side of the diaphragm 16 to be sent to the air motor 2,
A nut runner characterized in that the pressing force of a spring 18 is applied to the opposite surface of the diaphragm 16. 2. The utility model according to claim 1, wherein the valve body 9 and the diaphragm 16 are integrally connected by a connecting rod 19, and the valve body 9 and the diaphragm 16 move in conjunction with each other. Natsu runner. 3 The rear end of the spring 18 is supported by a nut 24, which is screwed into an adjustment bolt 23, and by rotating the adjustment bolt 23 and moving the position of the nut 24, the pressing force of the spring 18 can be reduced. The adjustable nut runner according to claim 1. 4 A valve body 9 is movably provided in a valve chamber 7, this valve chamber 7 communicates with an air supply port 8 to which an air supply pipe is connected, and a ventilation passage is provided in a valve seat 11 with which the valve body 9 comes into contact and is separated. 12 is formed, this ventilation passage 12 communicates with a ventilation passage 13 to the air motor 2, and this ventilation passage 1
3 and the front chamber 15a of the diaphragm 16 communicate with each other through a ventilation hole 17.