JPS5845809A - Prevention against spindle head dropping in hydraulic- drive copy milling machine - Google Patents

Abstract

PURPOSE:To surely prevent a spindle head from dropping, by connnecting a selector valve for dropping prevention use, which switches from the hydraulic power source side to the drain side, and vice versa, to a spindle head holding cylinder. CONSTITUTION:At the stoppage of machining, a solenoid 21a of a dropping prevention selector valve 21 is demagnetized, a port is shifted by force of a spring 21b and compressed oil on the lower part of a piston 18a of a spindle head holding cylinder 18 is discharged to the drain side. Thereupon the piston 18a and rod 18b of the cylinder 18 go down by energizing force of a spring 20 and a chain 15 gets tensed whereby a spindle head 5 goes up via rods 14b and 14c of a balancing cylinder 14. The spring constant of the spring 20 is being set so as to be larger than a dead load of the spindle head 5 which is therefore dynamically bound at a top dead point so that the spindle head is no longer dropped.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spindle head fall prevention device for a spindle head-overhead type hydraulic rotary image milling machine, and particularly to a spindle head fall prevention device suitable for improving reliability.

FIG. 1 shows an example of a hydraulic circuit for above and below the spindle of a conventional hydraulic rotary image milling machine, and this will be described below.

In the figure! is a hydraulic pressure generating device having a hydraulic pump 2. Hydraulic pressure supplied from this hydraulic generating device l is supplied to the top and bottom of the piston 4a of the balancing cylinder 4 via the balancing circuit 8, and the rod 4bK of the balancing cylinder 4. Connected spindle head 6
K is set so that it balances gravity. The hydraulic pressure supplied from the hydraulic pressure generating device 1 is also: It is transmitted to the copying device 7 via the hydraulic differential circuit 6, and from this device 7 the hydraulic differential circuit 6 is transmitted.
The image signal fed back to the arad 8b is the main axis 1
The signal is transmitted to either the upper or lower piston 8a of the upper and lower cylinders 8 connected to the cylinder 15.

Then, a delicate differential oil pressure proportional to a model or template (hereinafter referred to as model) 9 is generated above and below the piston 8a, and this differential pressure causes the piston 8a to move up and down to follow the model 9, thereby moving the main shaft aSt. It is designed to move up and down at high speed.

In Fig. 1, the accumulator 1G is filled with 10tli peroxide, and this accumulator 1G is the solenoid I
By switching the anti-drop valve 11 between IIL, spring timl, and tV, the discharge fill housing of the hydraulic pump 2 is connected to the lower side of the piston 4a of the balancing cylinder 4. A check valve 12- is provided between the balancing cylinder 4 and the balancing and combining circuit 8.

In the above configuration, when the power is turned on, the solenoid tla of the anti-fall valve 11 is energized and the akiemulator I
G is connected to the discharge port of the hydraulic pump 2.

Over the winter, hydraulic oil is accumulated in the accumulator 10 at a pressure equal to the nitrogen pressure sealed therein.

On the other hand 1. When the oil pressure becomes 0FIF, the hydraulic pressure generator-17)
Hydraulic pump 2 stops and the operating oil pressure becomes atmospheric pressure.

In addition, the hydraulic pressure applied above and below the piston 4a of the balancing cylinder 4 also becomes atmospheric pressure. At the same time K.

The solenoid Il& of the anti-fall valve 11 is demagnetized, and its spring 11'b shifts the support port so that the accumulator 1
0 is connected to the lower part side of the piston 41 of the balancing cylinder 4. As a result, the pressure oil accumulated in the accumulator 10 is supplied to the lower part of the piston 4a, and the spindle head 60 is prevented from falling due to its own weight. The check valve 12 prevents the pressure oil from the oil pressure generator lO from being released to the atmosphere W side of the oil pressure generator l.

As explained above, in the nine conventional devices, the fall prevention F of the spindle @6
i. It is made using high pressure oil that balances its own weight. Therefore, it is not possible to prevent a small amount of pressure oil from leaking from the spool of the fall prevention valve 11 or the check valve 12, and as a result, the spindle @ device gradually falls as time passes. Ruru.

If the achievable emulator lO and the balance cylinder 4 are not connected by the stick of the spool of the fall prevention valve 11, there is a risk that the spindle head 6 will rapidly fall under its own weight when the spindle head 6 is not in contact with the balance cylinder 4. Conversely, the solenoid l of the fall prevention valve 11
If the spool of the drop prevention valve 11 is shifted during machining due to burnout of the l&, there is a risk that the balance will be lost due to the pressure oil from the accumulator lO, and the spindle head 6 will repeatedly move up and down rapidly.

Furthermore, if the nitrogen pressure to be sealed in the accumulator 10 is set to a non-light range, or if there is a chance of nitrogen leaking in the light range at the time of setting, the fall prevention valve 11 may not operate properly. Also, the oil pressure of the pressure oil supplied from the Akiemulator 10 to the lower part of the piston 41 of the balance cylinder 4 becomes low with respect to the weight of the main shaft 1g5.

Therefore, it is not possible to prevent the spindle head 6 from falling.

Conventional spindle head fall prevention devices that operate in oil fields, such as those used in oil fields, have unstable operation and the risk of the spindle head gradually falling over time. This invention was made in order to solve the problems of the conventional method, and its purpose is to ensure that the ζ-lower is operated in one direction and to completely prevent the spindle head from falling. K provides a main shaft l1IWr lower prevention device for a hydraulic rotary image milling machine.

The present invention will be described below based on an embodiment shown in FIG.

In the figure, the hydraulic pressure generator 1 has a hydraulic pump 2 (To#), and the hydraulic pressure supplied from the hydraulic pressure generating device 1 is supplied to a double-sided balanced cylinder 14 having a lower rod 141) and an upper rod i+c. The piston 14 is supplied to the top and bottom, and the main shaft head 6t connected to the lower scI head 1411K is balanced by gravity. The hydraulic pressure supplied from the hydraulic pressure generating device 1 is also transmitted to the copying device 7 via the % hydraulic differential circuit 6, and the copying signal fed back from the imaging device 7 to the hydraulic differential circuit 6 is transmitted to the arad 8b. Spindle head 5
The hydraulic pressure is transmitted to either the upper or lower piston 8a of the upper and lower cylinders 8 connected to the upper and lower cylinders 8 to generate a slight differential hydraulic pressure proportional to the cylinder delta 9. Then, P [19. The spindle head 6 follows the seven delta 9 and is moved up and down at high speed.

The upper rod 14 (j of the balancing cylinder 14 has a second
As shown in the figure, one end of the chain 15 is connected to the main shaft head holding cylinder 18 via a chain sprocket 16.17 which functions as a fixed pulley. rod 181).

The spindle head holding cylinder 18 is composed of nine oil cylinders 18C fixed to the drilling machine foundation 19, a piston 181 and a rod 18b housed in the oil cylinders 18C.

A spring force having a spring constant equal to or greater than the force balanced with the weight of the spindle head 6 is incorporated in the piston 18 turtle portion 1cFi. Further, the lower part of the piston 18a is connected to the discharge side or the drain side of the hydraulic pump 2 by switching the ports of the solenoid 21a barb 2111 and the t-V drop prevention valve 21.

Next, the effect will be explained.

During normal machining, the hydraulic pressure generator 1i is first activated. Then, the pressure I'll from the hydraulic bonder 2 is supplied to the piston 14 & up and down of the balancing cylinder 14 through the balancing circuit 8t, and the spindle head 6 is balanced by gravity.

At the same time, the solenoid 211L of the fall prevention valve 21 is energized, and the pressure oil from the hydraulic pump 2 is supplied to the lower part of the piston 18a of the spindle head holding cylinder 18 via the fall prevention valve 21. When the oil pressure at the bottom of piston 1B rises and overcomes the force of the spring array, piston 10 and a
8b moves upward against the biasing force of the spring, and the chain 15
As soon as he became free, he started fishing.

The restraint by the holding cylinder 18 of the main shaft am, which has already been balanced by gravity by the matching cylinder 14, is released.

This makes it possible to perform rotary image processing using the upper and lower cylinders 8.

When processing is stopped, first solenoid n of the fall prevention valve 21 is
a-bX is demagnetized and its ports are tufted by the force of the spring 211), and the pressure oil in the main spindle head holding cylinder 18 mepiston 1B & lower part is discharged to the drain side. Then, due to the urging force of the spring 200, the piston 18a of the spindle head holding cylinder 18,
The rod 18 is lowered and the chain 15 is tensed, which causes the rod 14b of the balance cylinder 14 to tighten.

The main shaft s6 rises via 146. At this time, since the spring constant of the spring array is set to be larger than the weight of the main shaft @a as described above, the main shaft fi5ti is mechanically restrained at the top dead center position and will not fall below #r.

F if the entire milling machine loses power due to a power outage accident, etc.
i. The solenoid 21a of the drop prevention valve 21 is demagnetized, but in this case, the spindle head 5 is automatically raised by the spring 4 of the spindle head holding cylinder 18, and the spindle head 5 is lifted up automatically, as in the case when the machining is stopped. It is safely restrained at a point position.

During machining, if the oil pressure supply function is suddenly lost and the supply oil pressure drops to the atmospheric pressure level, the spindle head holding cylinder 18
The pressure at the bottom of the piston 18 is atmospheric pressure. Then,
The piston 1B& is lowered by the biasing force of the spring 20, and the spindle head 5 safely rises to the top dead center position and is semi-permanently restrained.

If the spool of the anti-drop valve 21 sticks and becomes inoperable when processing is stopped, hydraulic pressure continues to act on the lower part of the piston 18a of the spindle head holding cylinder 1B, so the piston te
A is in a state of being raised against the force of the spring. In this case, the hydraulic pump 2 should be stopped and the piston 1B
& Set the lower oil pressure to atmospheric pressure level. Then, the piston 18 is moved downward by the biasing force of the spring 20, and the spindle head 6 is permanently fixed at the top dead center position.

In either case, the main shaft fIA5 is fixed at the top dead center position by the biasing force of the spring 20, and its fall is effectively prevented. Further, since the main shaft @6 is mechanically fixed by the spring 20, one operation is real and stable.

In the embodiment described above, the case where the upper rod 14a of the balancing cylinder 14 and the rod 18b of the spindle head holding cylinder 18 are connected via the chain 15 has been described, but the present invention is not limited to this, and other strings such as wire ropes may be used. However, numerous modifications and changes may be made without changing the gist of the claimed invention.

The present invention has been described above based on the preferred embodiments. First, the present invention includes a balance cylinder t-, a lower rod that projects below the piston and is connected to the spindle head, and an upper rod that projects above the piston. The upper part is connected via a string to the rod of a holding cylinder, which is equipped with a spring having a spring constant tv greater than the weight of the spindle head, and the holding cylinder is connected to the hydraulic source side. Since all fall prevention switching valves that switch between the drain side and the drain side are connected, it is possible to reliably prevent the spindle head from falling. ``Il large operation and stable holding state of the spindles. Therefore, reliability as a milling machine can be dramatically improved.

[Brief explanation of drawings]

11 is a system diagram showing a conventional example, and FIG. 2 is a system diagram showing an embodiment of the present invention. l...Hydraulic pressure generator, 2...Bending pump, 8...
Balancing circuit, 6... Spindle head, 7... Copying Wts s.
...Upper and lower cylinder, 14...Balancing cylinder, 14a,
18m...piston. 14m)...lower rod, 140...upper rod,
tS--Chain, 18...Spindle head holding cylinder%181)--Rod. 18e...Oil cylinder, 19...Shinkaiki #, 20.21
11...Spring. 21... Fall prevention valve, 21a... Solenoid. Outgoing Agent Kiyohisa Inomata 1 Figure 6% Fan 2 Figure

Claims (1)

[Claims] Hydraulic rotation image that supplies hydraulic oil from a hydraulic source to a balancing cylinder via a balancing circuit to balance the head of the spindle gravity-wise, and also applies image signals from a copying device to the upper and lower cylinders to move the head of the spindle up and down. In the milling machine i, the balancing cylinder is formed into a double rod shape having a lower rod protruding below the piston and connected to the spindle head, and an upper rod protruding above the piston, and the upper rod is A spring with a spring constant tW greater than the weight of the spindle head is connected via a string to the a-rad of the holding cylinder, and the oil pressure iIl! A fall prevention device for a spindle head of a hydraulic rotary image milling machine, characterized in that a drop prevention switching valve for switching between # and drain threat is connected to a t-connection valve.