JPS5928139Y2 - air-driven hydraulic pump - Google Patents

Description

[Detailed description of the invention] This invention is a hydraulic overload safety device used in presses, etc.
This invention relates to an air-driven hydraulic pump that supplies pneumatically increased pressure oil to hydraulic actuators such as die clampers and lifters.

In a conventional air-driven hydraulic pump, a piston rod of a piston that fits an air cylinder is passed through the hydraulic chamber 1 to form a hydraulic piston, and the required hydraulic pressure is generated by the ratio of the pressure-receiving areas of the piston and the hydraulic piston.

Therefore, the discharge amount per shot was determined by the product of the area of the hydraulic piston and the stroke, and was constant regardless of the level of oil pressure.

In addition, there is a limit to the size of air-driven hydraulic pumps, and it takes a lot of time to discharge a large amount of oil, and recovery is slow for devices that require large amounts of oil, such as hydraulic overload safety devices. There was a drawback.

In reality, when refueling these actuators, more than 80% of the amount of oil can be supplied at low pressure, with the remaining approximately 2
Only high pressure is required for 0% refueling.

Therefore, if there is an air-driven hydraulic pump that has a large discharge amount at low pressure and a small discharge amount at high pressure, the refueling time can be shortened.

The purpose of the present invention is to meet this demand, and to provide an air-driven hydraulic pump that automatically switches between a large discharge volume at low pressure and a small discharge volume at high pressure during refueling, and has good work efficiency.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, the structure of the embodiment and the required air and hydraulic circuits are shown.

The air-driven hydraulic pump according to the present invention includes an air cylinder 4, an air hydraulic cylinder 5, and a hydraulic chamber concentrically integrated in order.

A piston 3 is fitted into the air cylinder with a stroke S1, and a piston 6 is fitted into the air-hydraulic cylinder 5 with a stroke S2.

A cylindrical piston rod of the piston 6 passes through a partition wall between the piston 6 and the hydraulic chamber 8 in an oil-tight manner so as to be freely slidable.

One piston rod 3a of the piston 3 passes through the partition wall between it and the pneumatic hydraulic cylinder 5 in an air-tight manner so as to be freely slidable, and further passes through the center portion 6a of the piston 6 in an oil-tight manner so as to be freely slidable therein.
The piston 6 protrudes into the cylindrical chamber 6b, and a cap screw 7 is screwed into its tip to prevent the piston 6 from being removed.

The length of the piston rod 3a is such that when the piston 3 is at the end in the direction of arrow F, the piston 6 is also pulled toward the end in the same direction.

Rubber rings 9, 10, 11, and 12 are provided at the stroke end of the piston 3 and the piston 6 to cushion the impact at the stroke end.

The other piston rod of the piston 3 is connected to the air cylinder 4
The end face of the is slidably passed through the end face of the
0 is fixed.

Limit switches 18 and 19 are fixed to the air cylinder 4, operated by a backing plate 20 at the stroke end of the piston 3.

Supply/discharge ports 4a and 4b of the cylinder chamber of the air cylinder 4;
Furthermore, compressed air from an air source 21 is adjusted to a constant pressure by a pressure reducing valve 1 and supplied to and discharged from the air supply and discharge port 5a of the cylinder chamber of the pneumatic hydraulic cylinder 5 via a solenoid valve 2.

A speed control pulp 13 is provided in a circuit leading to the supply/discharge port 4a of the right cylinder chamber of the piston 3.

While the hydraulic pressure discharged from the hydraulic chamber 8 is low, the pump efficiency is achieved by making the time for the piston 3 to move a stroke S1 in the direction of the arrow E approximately equal to the time for the piston 6 to move a stroke S2 in the direction of the arrow E. This is to improve.

The reason is that the force that the piston 3 receives via the piston rod 3a due to the hydraulic pressure in the hydraulic chamber 8 is smaller than the force that the piston rod of the piston 6 receives, and the pressure receiving area of the piston 3 is larger than the pressure receiving area of the piston 6. This is to prevent 3 from moving too quickly.

Although the air circuit is cut off in the middle, A-A and B-
B is in contact with each other.

The hydraulic chamber 8 has a circuit that sucks oil from an oil supply source 15 through a check valve 17 that opens toward the hydraulic chamber 8, and a circuit that sucks oil through a check valve 16 that opens toward the hydraulic overload safety device 14. A discharge circuit is provided.

Next, we will discuss the effect.

FIG. 1 shows a state in which the hydraulic chamber 8 and the cylindrical chamber 6b of the piston 6 are filled with oil, the pistons 3 and 6 are at the ends in the direction of arrow F, and the backing plate 20 operates the limit switch 19 and the solenoid valve 2 is activated. This shows the state switched to the state shown in the figure.

In this state, the compressed air is speed control pulp 1
3 to the supply/discharge port 4a of the air cylinder 4 and directly to the supply/discharge port 5a of the air-hydraulic cylinder 5.

While the pressure in the hydraulic chamber 8 is low, the pistons 3 and 6 move in the direction of the arrow E by strokes S1 and S2, respectively, and the piston rod 3a of the piston 3 and the piston rod of the piston 6 pressurize the oil in the hydraulic chamber 8, and vice versa. A large amount of pressure oil is supplied to the hydraulic overload safety device 14 via the stop valve 16 .

At the end of the stroke, the stop plate 20 of the piston 3 operates the limit switch 18, and the solenoid valve 2 is switched by the output thereof.

When air is exhausted from the air supply ports 4a and 5a and simultaneously supplied with air from the air supply port JbK of the air cylinder 4, the piston 3 moves in the direction of arrow F.
While moving in the direction, the piston 6 is pulled by the cap screw 7 of the piston rod 3a, and both reach the stroke end at the same time.

At the end of the stroke, the backing plate 20 operates the limit switch 19, and the output switches the solenoid valve 2, and the above is repeated, so that the required discharge amount of about 80φ is supplied.

When the pressure in the hydraulic chamber 8 starts to rise, the speed of the piston 6 moving in the direction of the arrow E relative to the piston 3 gradually slows down, and the piston rod 3a gradually moves back into the cylindrical chamber 6b. The oil discharge amount decreases, and when the hydraulic pressure of the piston rod becomes greater than the pneumatic pressure of the piston 6, the piston 6 stops moving.

That is, when the pressure in the hydraulic chamber 8 becomes high, only the piston 3 strokes, and a small amount of pressure oil is supplied by the piston rod 3a to the hydraulic overload safety device 14 via the check valve 16. Stop.

Automatically starts when oil pressure drops.

As is clear from the above explanation, according to the present invention, the actuator side can automatically switch to a large discharge amount when the pressure is low, and automatically switch to a small discharge amount when the pressure becomes high, which improves work efficiency and has practical benefits. It has great effects and benefits.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view and a necessary circuit diagram of an embodiment equipped with a hydraulic overload safety device. 1 is a pressure reducing valve, 2 is a solenoid valve, 3 is a piston, 4 is an air cylinder, 4a, 4b are supply/discharge ports, 5 is an air hydraulic cylinder, 5
a is the supply/discharge port, 6 is the piston, 6a is the center, 6b is the cylindrical chamber, 7 is the cap screw, 8 is the hydraulic chamber, 9, 10, 1
1.12 is a rubber ring, 13 is a speed control pulp, 14 is a hydraulic overload safety device, 15 is an oil supply source, 1
6゜17 is a check valve, 18 and 19 are limit switches, 2
0 is a backing plate, and 21 is an air source.

Claims (1)

[Scope of utility model registration request] A sequential air cylinder, an air hydraulic cylinder, and a hydraulic chamber are integrally provided, and the cylindrical piston rod of the piston 6 that fits the air hydraulic cylinder is passed through the hydraulic chamber oil-tightly and slidably, and the air The piston rod of the piston 3 that fits the cylinder is passed through the pneumatic hydraulic cylinder in an airtight and slidable manner, and the center of the piston 6 is passed through the piston 6 in an oil-tight and slidable manner. The piston 6 is prevented from being removed by a cap screw protruding from the tip and screwed into the tip thereof, and the piston 6 is prevented from being removed, and the air cylinder supply and discharge ports 4a and 4b and the pneumatic hydraulic cylinder supply and discharge port 5aK are
In addition to supplying and discharging compressed air at a constant pressure, a speed control pulp is provided in a circuit leading to the supply/discharge port 4aK, and an oil suction circuit is provided in the hydraulic chamber via a check valve that opens from an oil supply source to the hydraulic chamber; An air-driven hydraulic pump characterized by being provided with an oil discharge circuit via a check valve that closes toward a hydraulic chamber up to a hydraulic actuator.