JPH04157206A - Hydraulic cylinder with intensifier - Google Patents

Abstract

PURPOSE:To miniaturize the above hydraulic cylinder by disposing a pressure intensifying piston whose part is inserted in a heat side hydraulic pressure chamber of a main cylinder from a main cylinder outer peripheral part directly between a main piston and a main piston rod projecting side edge plate of the main piston. CONSTITUTION:A pressure intensifying tube 5 formed integratedly with a pressure intensifying piston 4 is accommodate in a main cylinder 1 slidably, a main piston rod 3 is made to pass through a central hole of the pressure intensifying piston 4 slidably, and a main piston 2 is accommodated in the pressure intensifying tube 5 slidably. Besides, an oil chamber 12 on the main cylinder 1 bottom side of the main piston 2 is communicated with the third port 13, an oil chamber 8 on the pressure intensifying piston 4 side is communicated with the second port 9 through a through hole 10 and a groove 11 of the pressure intensifying tube 5, and a pressure intensifying oil chamber 6 between the pressure intensifying piston 4 and a rod side edge plate 1a of the main cylinder is communicated with the first port 7. It is thus possible to miniaturize only by adding the pressure intensifying pistons 4, 5 inside the main cylinder 1.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a hydraulic cylinder having a pressure increasing function, and is particularly suitable for use in, for example, crushing equipment, which requires a pressure increasing function as necessary. Regarding.

(Prior art and problems to be solved by the invention) Conventional devices for increasing the discharge pressure of a hydraulic pump in the same circuit include one that uses a combination of a hydraulic motor and a hydraulic pump;
There are devices that use pressure booster cylinders. FIG. 6 is an example of this. For example, as shown in FIG. 7, an opening/closing arm 31 that is opened and closed by a hydraulic cylinder 30 is attached to a bracket 36 that is attached to the arm of a working machine so that it can be opened and closed around a bin 37. In this crushing apparatus, as shown in FIG. 6, a pressure increasing cylinder 32 is provided, and a control valve 33
When crushing work is performed by switching the hydraulic cylinder 30 to the left position, extending the hydraulic cylinder 30, and closing the opening/closing arm 31, the object to be crushed is difficult to crush, the pressure in the circuit 34 increases, and when the sequence valve 35 is activated, the pressure increases. Cylinder 32 operates,
The hydraulic cylinder 30 operates with increased pressure oil to obtain a large output. Note that a hydraulic pump and a hydraulic motor may be used instead of the pressure increase cylinder 32 shown in FIG.
In any case, a pressure increase cylinder 32 is installed outside the main cylinder 30.
Alternatively, there is a problem in that the entire device becomes large because it is equipped with a hydraulic pump and a hydraulic motor.

Furthermore, as disclosed in Japanese Patent Publication No. 59-16613, there is a system in which a pressure booster cylinder is integrated in series with the main cylinder, but the problem is that the overall length of the cylinder becomes longer, resulting in an increase in the overall size of the device. there were.

The present invention has been made in view of these problems, and an object of the present invention is to provide a hydraulic cylinder having a pressure increasing function and having a structure that can achieve miniaturization.

(Means for Solving the Problems) In order to achieve this object, the present invention disposes a main piston pressure increasing piston between the main piston and the main piston rod protruding end plate of the main cylinder, and provides a pressure increasing piston. The feature is that the part that is integrated with the main cylinder is directly inserted into the head side hydraulic chamber of the main cylinder.

In the present invention, in the above structure, a structure can be adopted in which one or more piston rods are used as a part that is integrated with the pressure increasing piston.

Further, the main piston rod is made hollow and a pressure increasing piston is accommodated therein, and the pressure increasing piston integrated with the pressure increasing piston is slidably penetrated through the main piston, and the pressure increasing piston and the main piston rod hollow part are connected to each other. A configuration is adopted in which the pressure is supplied to a pressure increasing hydraulic chamber provided in between through a pipe that passes through a pressure increasing piston rod.

(Function) The hydraulic cylinder according to the present invention has the above-described structure, and by pressing the pressure increasing piston with the pressure oil, high pressure is generated on the head side of the main piston, and the main piston rod is pressed with high pressure.

(Embodiment) FIG. 1 is a longitudinal sectional view showing an embodiment of a hydraulic cylinder according to the present invention in a contracted state, and FIG. 2 is a longitudinal sectional view showing the same in an extended state. 1 is a main cylinder of the main cylinder, 2 is a main piston, 3 is a main piston rod integrated with the main piston 2, 4 is a pressure increasing piston, and 5 is a pressure increasing tube integrated with the pressure increasing piston 4. be.

The pressure increasing piston 4 and the pressure increasing tube 5 are slidably housed in the main cylinder 1, and the main piston rod 3 is slidably inserted through the center hole of the pressure increasing piston 4. A pressure increasing hydraulic chamber 6 is formed between one side of the pressure increasing piston 4 and the rod side end plate 1a of the main cylinder 1, and a first boat 7 communicating with the pressure increasing hydraulic chamber 6 is connected to the main cylinder. It is provided in l.

The main piston 2 has a larger cross-sectional area than the pressure increasing tube 5, and the main piston 2 is slidably fitted into the pressure increasing tube 5.

Further, a hydraulic chamber 8 between the main piston 2 and the pressure increasing piston 4 in the pressure increasing tube 5 is connected to a second boat 9 provided in the main cylinder through a through hole 10 provided in the pressure increasing tube 5. and a groove 1 provided all around the outer surface of the pressure boosting tube 5.
1 through a passageway.

Further, a hydraulic chamber 12 on the opposite side of the main piston rod 3 of the main piston 2 (the end surface of the pressure increasing tube 5 faces the hydraulic chamber 12) is connected to a third boat 13 provided in the main cylinder l. communicate. 14 to 18 are O-rings.

In this configuration, the cross-sectional area of the pressure increasing piston 4 is now A
, the cross-sectional area of the pressure increasing tube 5 is B, the cross-sectional area of the main piston 2 is C, a load is connected to the main piston rod 3, and the first
The boat 7 is connected to a hydraulic pressure source and the hydraulic pressure is connected to
the third boat 9 communicating with the oil tank, and blocking the third boat 13 communicating with the hydraulic chamber 12 facing the main piston 2;
If the hydraulic pressure in the hydraulic chamber 12 is Pl, then PlxA=P2xB holds true, and the hydraulic pressure in the hydraulic chamber 12 is increased by the area ratio A/B. The main piston rod 3 is then pushed out by a force of P2xC due to the increased hydraulic pressure P2. Here, the force P2x C pushing the main piston 2 and the pressure increasing piston 4
The ratio of the pushing force to PIXA is (P2X C) / (P
IX A ) = (P2xC) / (Plx (P2
xB/PI))-C/B Therefore, the larger the ratio (C/B) of the cross-sectional area C of the main piston 2 to the cross-sectional area B of the pressure-increasing tube 5, the greater the force-increasing effect.

FIG. 3 is an example of a hydraulic circuit configured to use the hydraulic cylinder of this embodiment in place of the hydraulic cylinder 30 of the crushing device shown in FIG. 7, in which 19 is a hydraulic power source, 20 is an oil tank, 21 is a control valve; 22 is a sequence valve that opens when the pressure in the circuit 23 to which pressure oil is supplied when extending the hydraulic cylinder of the above embodiment rises above a predetermined value;
24 is a switching valve, and 25 is an operation chamber 24 of the switching valve 24.
26 is a check valve connected in parallel to the throttle valve 25, and the spring 24b of the switching valve 24 is connected to the pressure increasing piston 4 or the pressure increasing piston 4. The pressure in the operation chamber 24a is not switched depending on the pressure level in operation, and the hydraulic pressure in the secondary side circuit 29 reaches the stroke end of the pressure increasing tube 5, or when the pressure increases to near the maximum pressure in the operation chamber 24a. The relative spring force is set. 27 is a pilot check valve that opens when the pressure in the circuit 28 increases.

In the circuit shown in FIG. 3, the control valve 21 is switched to the left position and the pressure oil from the hydraulic source 19 is transferred to the control valve 21,
Hydraulic chamber 1 through circuit 23 and pilot check valve 27
2 is supplied with pressure oil from the third boat 13, the oil in the hydraulic chamber 8 in the pressure increasing tube 5 returns to the oil tank 20 from the second boat 9 through the switching valve 24, circuit 28, and control valve 21, and the oil pressure increases. The cylinder extends and the opening/closing arm 3
1 or close and crushing is performed. When the object to be crushed is difficult to crush and the hydraulic pressure in the circuit 23 rises and exceeds the set pressure of the sequence valve 22, the sequence valve 22 opens, but the pressure during the pressure increasing operation of the pressure increasing piston 4 is Since it is not switched and is maintained at the right position as shown in the figure, pressure oil is supplied from the first boat 7 to the pressure increasing hydraulic chamber 6 through the switching valve 24, and the main piston 2 is supplied with pressure oil increased in the hydraulic chamber 12. Since the opening/closing arm 31 is pushed, the crushing force by the opening/closing arm 31 increases and crushing is performed. When the pressure increase tube 5 moves to the left and reaches the stroke end, or when it reaches near the maximum pressure for pressure increase, the oil pressure in the secondary circuit 29 of the sequence valve 22 increases, and the switching valve 2
The switching valve 24 is switched to the left position by overcoming the operating force of the hydraulic pressure in the operating chamber 24a and the force of the spring 24b. The pressure increasing piston 4 is then returned to the right position in FIG. Then, the spring 2 is passed through the throttle valve 25.
4b pushes oil out of the operation chamber 24a, the switching valve 24 returns to the right position, the main piston 2 is again pressed by the oil pressure from the oil pressure source 19, and when high pressure is generated in the circuit 23 again, the increase in pressure is resumed. The pressure device is activated. Note that the stroke end of the pressure increasing tube 5 may be detected by a limit switch.

FIG. 4 shows another embodiment of the present invention, in which the main piston 2
is slidably accommodated inside the main cylinder 1, and a plurality of rods 5A are integrally provided in place of the pressure increasing tube 5 by being connected to the pressure increasing piston 4, and each lot 5A
is slidably inserted into the hole of the main piston 2 via an O-ring 40. Furthermore, in this embodiment, the second boat 9 is not provided in the body of the main cylinder l, but is provided in the end plate 1b of the main tube l, and the hydraulic chamber 8 between the main piston 2 and the pressure increasing piston 4 is provided. In order to communicate with the second boat 9, the main piston rod 3 is formed into a hollow shape with a hollow portion 3a, and the hollow portion is communicated with the hydraulic chamber 8 through a through hole 3b, so that the second boat 9 and the hollow portion 3a are communicated with each other through a vibrator 41 which has one end fixed to the end plate ib and is slidably fitted via an O-ring 42.

In this embodiment, the hydraulic chamber 12 is
The increased oil pressure is obtained, and the main piston 2 is pushed by the increased oil pressure.

In the embodiments shown in FIGS. 1 and 2, as shown in FIG. It may be communicated with the boat 9, and conversely, in the embodiment shown in FIG. 4, the hydraulic chamber 8 is provided in the body of the main cylinder l as shown in FIGS. 1 and 2! It may also have a structure in which it communicates with the $2 boat 9.

FIG. 5 shows another embodiment of the present invention, and in FIG. 4, the main piston rod 3 is made into a hollow shape and also serves as a pressure increasing cylinder, and the pressure increasing piston 4 provided in the pressure increasing cylinder and this The piston rod 4a integrated with the main cylinder 1 is directly inserted into the head side hydraulic chamber 12 of the main cylinder 1.

That is, the pressure increasing piston 4 is slidably accommodated in the hollow portion 3a of the main piston rod 3 via an O-ring 43.
A pressure-increasing piston rod 4a integrated with the main piston 2 is slidably passed through the center hole of the main piston 2 via an O-ring 44, and one end is fixed to the end plate 1b of the main cylinder 1 within the pressure-increasing piston loft 4a. The vibrator 41 is slidably fitted through the O-ring 42, and the end of the vibrator 41 is used as the boat 7 of the I81, and communicated with the pressure increasing hydraulic chamber 6 through the vibrator 41. In addition, a hollow portion 3a between the pressure increasing piston 4 and the main piston 2 in the main piston rod 3 is connected to a $2 boat through a through hole 3b provided in the main piston 3 and a hydraulic chamber 8 on the outer surface of the main piston 3. Connect to 9.

In this embodiment as well, high pressure is generated in the hydraulic chamber 12 by communicating the second boat 9 with the oil tank, closing the third boat, and supplying pressure oil from the first boat 7.
Push out the main piston 2 with high pressure.

Comparing the above-mentioned embodiments, the embodiment shown in FIGS. 1 and 2 can be implemented by simply adding the pressure-increasing piston 4 and the pressure-increasing tube 5 to a normal hydraulic cylinder, and has a simple structure. , it has the advantage that it can be implemented at low cost, but the diameter of the main cylinder 1 becomes slightly larger.

The embodiment shown in FIG. 4 has the advantage that the diameter of the main cylinder 1 and the diameter of the main piston rod 3 can be implemented almost unchanged from those of general ones, but the number of parts is greater than that of the previous embodiment.

The embodiment shown in FIG. 5 has the advantage that, like the embodiment shown in FIG. It has the advantage of being able to be constructed with fewer parts.

Further, the operating range of the pressure increasing piston 4 can be made longer than the length of the main cylinder 1, which has the advantage that the pressure increasing piston 4 can have a large stroke. However, since the diameter of the main piston rod 3 is increased, the force required when the main piston rod contracts is small, and this is effective when it is desired to reduce the diameter of the main cylinder 1.

Although the above embodiments have all been shown for single-loft type hydraulic cylinders, the present invention can also be applied to double-loft type hydraulic cylinders.

(Effect of the invention) According to claim 1, since the pressure increase device is housed in one hydraulic cylinder, the overall size of the device is significantly reduced compared to the conventional pressure increase device provided externally. Can be made smaller.

Another advantage is that it can be easily implemented by simply adding a pressure increasing piston inside the main cylinder.

According to claim 2.3, the hydraulic cylinder having the pressure increase device can be further downsized.

[Brief explanation of drawings]

1 and 2 are vertical sectional views showing an embodiment of a hydraulic cylinder according to the present invention in a contracted and expanded state, respectively; FIG. 3 is an example of a hydraulic circuit for operating the hydraulic cylinder of the embodiment; and FIG. 5 and 5 are longitudinal sectional views showing other embodiments of the hydraulic cylinder according to the present invention, FIG. 6 is a hydraulic circuit diagram showing an example of a conventional hydraulic cylinder equipped with a pressure increase device, and FIG.
The figure is a schematic diagram of an example of a crushing device, which is an example of a device to which the present invention is applied. 1: Main cylinder, 2: Main piston, 3: Main piston rod, 4: Pressure increase piston, 4a: Pressure increase piston lot 5: Pressure increase tube, 5A: Pressure increase lot, 6: Pressure increase hydraulic chamber, 7: No. 1 boat, 8. 12: Hydraulic room, 9: 2nd boat, 13: 3rd boat

Claims (1)

[Claims] 1. A main piston pressure increasing piston is disposed between the main piston and the main piston rod protruding end plate of the main cylinder, and the part that is integral with the pressure increasing piston is A hydraulic cylinder with a pressure booster, characterized in that it is inserted directly into the hydraulic chamber on the head side of the cylinder. 2. The pressure increasing piston is integrated with one or more piston rods, and the piston rods penetrate the main piston and are inserted into the head side hydraulic chamber. Hydraulic cylinder with pressure booster. 3. The main piston rod is configured as a hollow pressure increasing cylinder, and the piston rod integrated with the pressure increasing piston provided in the pressure increasing cylinder is configured to be inserted directly into the head side hydraulic chamber of the main cylinder. Features: Hydraulic cylinder with pressure booster.