JP2592878Y2 - Pressure booster - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure intensifier, in particular, which can discharge a low pressure and a large flow rate and discharge a high pressure and a small flow rate, has a small number of parts, has a simple structure, and hardly causes a failure. The present invention relates to a pressure intensifier which is described below.

[0002]

2. Description of the Related Art In general, a pressure intensifier as a hydraulic element refers to a device that converts an inlet (primary) pressure into a high outlet pressure substantially proportional thereto, and a pneumatic or pressure source as a primary pressure source. Hydraulic pressure is frequently used, and hydraulic fluid or water-based liquid is often used as the secondary pressure medium.

A pressure intensifier is used to obtain a high pressure in a low pressure circuit, to generate an extra high pressure that cannot be reached by a conventional pump, or to use a pressure medium that is not suitable for a conventional rotary pump. Used when you want to use. Further, a pressure booster is also used when it is desired to easily construct a hydraulic pressure source using a factory air pressure source or when it is desired to secure a hydraulic pressure source such as high-precision fine-speed feeding.

[0004] Instead of the pressure intensifier, it is conceivable to use a motor pump such as a gear pump, a vane pump, or a piston pump driven by a conduction motor. However, these motor pumps are large-scale and expensive, and they are electrically expensive. Therefore, a control circuit and a control panel are required, which is expensive, and there is a disadvantage that energy is wasted when unloading. Further, when used in an explosion-proof atmosphere or a flammable atmosphere, special treatment is required to prevent explosion or fire from being generated by static electricity or sparks generated by intermittent electric current.

A typical pressure booster is an air hydraulic pressure booster (Aehydro Booster), which is used to combine the simplicity of pneumatic pressure with the good controllability of hydraulic pressure. It is used for work such as work clamping, feeding, caulking, bending, and opening and closing of a valve in a mechanical device such as a machine and a printing machine. In addition, a booster device is also used in a so-called booster brake of an automobile, and is going to be applied to a lubricating oil supply device of a large engine in the future.

A conventional pneumatic hydraulic pressure intensifier is shown in FIG.
As shown in the circuit diagram of FIG. 1, a tank 101 containing oil as a secondary side pressure medium, and oil in the tank 101 is sucked,
It has a pump 102 for pressurizing and discharging, and a pneumatic drive device 103 for driving the pump 102. Pump 10 above
2, as shown in the equivalent circuit diagram of FIG.
A hydraulic circuit in which a suction check valve 104 connected to a pump chamber 105 and a discharge check valve 107 connected to a load circuit 106 are connected in series, or as shown in an equivalent circuit diagram of FIG.
Between the suction check valve 104 and the discharge check valve 107 connected in series, a hydraulic circuit is formed in which a pump chamber 105 is branched and connected.

As the pneumatic drive device 103, FIG.
Alternatively, as shown in FIG. 11, a single-acting air cylinder is frequently used, and a plunger 109 connected to a piston 108 of this cylinder is moved forward and backward in the pump chamber 105 to thereby move the plunger 109 from a tank 101 through a suction check valve 104. The pump oil is sucked and the pressurized oil pressurized from the pump chamber 5 is discharged to the load circuit 106 via the check valve 107.

[0008] The compressed air which is the driving source of the pneumatic driving device 103 is 0.4 to 0.4% which is used as a factory air source.
0.5MPa compressed air is used and the pressure increase ratio is 4
Many are 5 to 50. Generally, the pressure increasing ratio of the pneumatic hydraulic pressure increasing device is up to about 100, and sometimes even more than 600. By the way, in this pneumatic hydraulic pressure booster, in order to increase the discharge amount, it is necessary to form the pump chamber 105 and the plunger 109 with a large diameter.
09 becomes large and it becomes difficult to make the discharge amount high.

Further, in order to increase the discharge pressure, it is necessary to reduce the diameter of the plunger 109 and reduce its pressure receiving area, so that it becomes difficult to increase the discharge amount.
The change in volume decreases, and the vacuum force in the pump chamber 105 decreases. Therefore, most of the conventional pneumatic hydraulic pressure intensifiers select either a low pressure large flow rate or a high pressure small flow rate.

Therefore, as disclosed in, for example, Japanese Patent Application Laid-Open No. 63-243501, a two-stage intensifier having a two-stage plunger and capable of controlling the discharge pressure and the flow rate in two stages has been proposed. Has reached.

[0011]

However, the two-stage pressure intensifier has a problem that the number of parts is large, the parts cost and the assembly cost are high, and the cost is high. In addition, the configuration is inevitably complicated, and a failure such as a plunger stack is likely to occur. The present invention has been made in view of the above circumstances, and can perform low-pressure large-flow discharge and high-pressure small-flow discharge. It is an object of the present invention to provide a pressure intensifier in which a failure hardly occurs.

[0012]

According to the present invention, a tank containing a secondary side pressure medium, a suction check valve, a pump chamber, a discharge check valve, and a load circuit are connected in series. In order to achieve the above object, in a pressure intensifier provided with a driving device that drives a plunger that can reciprocate into a pump chamber, in order to achieve the above object, the tank is constituted by a closed tank, and a preload means for increasing the internal pressure of the tank is provided. It is characterized by the following.

[0013]

In the present invention, since the internal pressure of the tank is increased by the preload means, when the load circuit is at a pressure lower than this internal pressure, a large amount of oil in the tank is pushed out by the internal pressure of the tank regardless of the change in the volume of the pump chamber. Thus, a large amount of pressure oil can be discharged to the load circuit.

Further, when the internal pressure of the load circuit is higher than the internal pressure of the tank, the pressure oil pressurized by the action of the pump driven by the driving device is supplied to the load circuit at a small flow rate corresponding to the volume change of the pump chamber. Discharged.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to clarify the present invention, a pressure booster according to an embodiment of the present invention will be specifically described below with reference to the drawings. However, the present invention is not limited to this embodiment. Absent. A pressure booster according to an embodiment of the present invention shown in the cross-sectional view of FIG. 1 and the circuit diagram of FIG. 2 includes a tank 1 for storing oil as a secondary-side pressure medium, and suction of oil in the tank 1. , A pump 2 for pressurizing and discharging, and a pneumatic drive device 3 for driving the pump 2.

As shown in FIG. 1, inside the pump 2
A hydraulic circuit in which a suction check valve 4 connected to the tank 1, a pump chamber 5 also serving as a valve chamber of the suction check valve 4, and a discharge check valve 7 connected to a load circuit 6 are connected in series. It is formed. The pneumatic drive device 3 is composed of a single-acting air cylinder, and moves a plunger 9 connected to a piston 8 in the pump chamber 5 so as to suck oil from the tank 1 through the suction check valve 4. The pressure oil pressurized from the pump chamber 5 is discharged to the load circuit 6 via the check valve 7.

The pneumatic driving device 3 includes the piston 8
The cylinder chamber 10 in which the cylinder chamber 10 is slidably fitted, and the cylinder chamber 10
The piston 8 has a pressure receiving chamber 11 defined on the upper side of the piston 8 in the drawing, and a return spring 12 for urging the piston 8 toward the pressure receiving chamber 11. 13
The connection is switched between the directional control valve 14 and the atmosphere, and the piston 8 moves forward and backward in the cylinder chamber 10.

That is, as shown in the enlarged sectional view of FIG. 3, the directional control valve 14 is formed in a stepped cylindrical shape, is arranged coaxially with the piston 8, and is provided in a valve chamber 15 having a stepped hole. It is slidably fitted inside. The large diameter portion 14a of the directional control valve 14 and the distal end of the small diameter portion 14b
Are externally fitted, and the space between the direction control valve 14 and the peripheral surface of the valve chamber 15 is hermetically sealed by these sealing members. And
An annular passage 17 is formed around the directional control valve 14 by reducing the diameter of the directional control valve 14 between the sealing member 16 of the small diameter portion 14b of the directional control valve 14 and the stepped surface.

The body 18 of the pneumatic drive unit 3 supports a control spool 19 which can enter and retract into the cylinder chamber 10 and the valve chamber 15. The control spool 19 communicates with the large-diameter portion of the valve chamber 15. A hollow portion 20 is formed. Also, this control spool 1
The lower end of 9 has a small-diameter portion 19a reduced in diameter over a section shorter than the stroke of the piston 8, and a head 19b expanded in diameter at the tip thereof, and is formed over the piston 8 and the plunger 9 connected to the piston 8. Hollow 21
The head 19b is inserted so as to be able to advance and retreat.

An inner collar 22 slidably fitted on the small diameter portion 19a of the control spool 19 is fixed to the piston 8, and when the piston 8 advances and retracts, the inner collar 22 pulls the head portion 19b and the hollow portion 21. By pressing the end of the head 19b, the control spool 19 is driven by a piston to advance and retreat over a predetermined stroke.
The direction control valve 14 has a control spool 19
Recess 14c of appropriate depth from the bottom to avoid interference with
Is formed.

In the body 18, the compressed air supply passage 13 communicates with the vicinity of the stepped surface of the large diameter portion 14a of the valve chamber 15 and a predetermined position of a spool insertion hole 23 through which the control spool 19 is inserted. A branch path 24 is formed. Also this body 18
In the inside, a pressurizing passage 25 that connects the annular passage 17 to the pressure receiving chamber 11 when the directional control valve 14 is located at the upper limit of the stroke is formed.

Further, in the body 18, the spool insertion hole 23 is opened from the opening position of the branch passage 24 at a position substantially the same as the stroke of the control spool 19 from the opening position of the branch spool 24 toward the cylinder chamber 10. A pressure relief passage 26 is formed therein, and a switching passage 27 is formed in the control spool 19 for selectively communicating the hollow portion 20 with the branch passage 24 and the pressure relief passage 26.

The compressed air supply passage 13 of the pneumatic drive device 3 is connected to a factory air source of 0.4 to 0.5 MPa.
Next, the operations of the pneumatic drive device 3 and the pump 2 will be specifically described with reference to the drawings. This pneumatic drive 3
When the pump 2 is at rest, the piston 8 and the directional control valve 14 are returned by the return spring 12 as shown in FIGS.
The control spool 19 is held at the top dead center, and the hollow portion 20 of the control spool 19 communicates with the branch passage 24 via the switching passage 27.

Therefore, when compressed air is supplied to the pneumatic driving device 3 through the compressed air supply passage 13, the directional control valve 14
Is urged to the top dead center by the compressed air, and the discharge process of the pump 2 starts. As shown in FIG. 4, in the discharge step, the compressed air supply passage 13 is divided into a branch passage 24, an annular passage 17 and a pressurization passage 25.
The piston 8 and the plunger 9 are lowered to reduce the volume of the pump chamber 5. When the internal pressure of the pump chamber 5 exceeds the internal pressure of the load circuit 6 by a certain amount or more, the discharge check valve 7 is activated. The valve is opened.

In the discharge step, the control spool 19 is urged toward the piston 8 by the differential pressure between the pressure received from the valve chamber 15 and the pressure received from the pressure receiving chamber 11, so that the control spool 19 is more urged than the piston 8 and the plunger 9. Descends late, valve chamber 15
The large diameter portion, the hollow portion 20 and the switching passage 27 are shut off from the branch passage 24 within a short time. Piston 8 and plunger 9
Is lowered to a predetermined position, the inner collar 22 fixed to the piston 8 receives the head 19b of the control spool 19, and thereafter the control spool 19 is moved by the piston 8 until the piston 8 and the plunger 9 descend to the bottom dead center. Forced reduction.

When the piston 8 and the plunger 9 descend to the bottom dead center, as shown in FIG. 5, the internal pressure of the pump chamber 5 decreases to near the internal pressure of the load circuit 6, the discharge check valve 7 is closed, and the discharge step is performed. Ends. At the end of the discharge process, the switching passage 27 of the control spool 19 which descends along with the piston 8 and the plunger communicates with the pressure release passage 26, and the large-diameter portion of the valve chamber 15 has the hollow portion 20 and the switching passage 27. The pressure of compressed air supplied from the compressed air supply passage 13 through the branch passage 24 and the annular passage 17 acts on the stepped surface of the directional control valve 14 while communicating with the atmosphere through the pressure release passage 26. I do.

As a result, the directional control valve 14 is instantaneously moved from the top dead center to the bottom dead center as shown in FIG.
The pressurizing passage 25 is communicated with the atmosphere through the upper end of the small diameter portion of the valve chamber 15, and the return spring 12 starts pushing up the piston 8 and the plunger 9, so that the suction process is started. In this suction step, the volume of the pump chamber 5 is increased,
Since the internal pressure of the pump chamber 5 decreases, as shown in FIG.
The suction check valve 4 is opened, and oil is sucked from the tank 1 via the suction check valve 4.

When the piston 8 and the plunger 9 are raised to a predetermined height, the end of the head 19b of the control spool 19 is pressed against the bottom surface of the hollow portion of the piston 8, and thereafter the return spring 12 passes through the piston 8 and the plunger 9. The control spool 19 is forcibly lifted until it reaches the top dead center. As shown in FIG. 8, when the piston 8, the plunger 9 and the control spool 19 reach the top dead center, the suction process ends, the switching passage 27 communicates with the branch passage 24, and the internal pressure of the large diameter portion of the valve chamber 15 is increased. Directional control valve 14
Rises and returns to the state at the start of the ejection process shown in FIG.

From the state at the start of the discharging step shown in FIG.
When the internal pressure of the load circuit 6 reaches a predetermined pressure at an arbitrary point in the discharge process during the transition to the state at the end of the discharge process shown in FIG. Pressure acting on plunger 9 from chamber 5 side and return spring
The biasing force of 12 and the pressure acting on the piston 8 from the pressure receiving chamber 11 are balanced, and the piston 8 and the plunger 9 stop.

At this time, since the direction control valve 14 is held at the top dead center, the pressure receiving chamber 11, the pressurizing path 25, the annular path 17 and the branch path 24 do not communicate with the atmosphere, and the compressed air supply path 13 The supply of compressed air from is stopped naturally. In this pressure increasing device, the tank 1 is constituted by a closed tank, and as a pre-pressurizing means for increasing the internal pressure of the tank 1, a compressed air supply path 13 for supplying compressed air to the pneumatic driving device 3 is provided by the tank 1.
And a branch pressure air passage 28 communicating with the air passage.

Therefore, while the compressed air is being supplied to the pneumatic driving device 3, the compressed air is supplied into the tank 1 through the branch pressure air passage 28, and the internal pressure of the tank 1 is reduced to the pressure of the compressed air (0.4 to 0.5). MPa), when the internal pressure of the load circuit 6 is lower than this internal pressure, the tank 1
A large amount of oil in the tank 1 is pushed out by the internal pressure regardless of a change in the volume of the pump chamber 5, and a large flow of pressure oil can be discharged to the load circuit 6.

When the internal pressure of the load circuit 6 is higher than the internal pressure of the tank 1, the pressure oil pressurized by the action of the pump 2 driven by the pneumatic driving device 3 corresponds to the change in the volume of the pump chamber 5. It is discharged to the load circuit 6 at a small flow rate. In this case, the pressure oil sucked into the pump chamber 5 is pressure-fed to the pump chamber 5 by the internal pressure of the tank 1, so that the reduction in the vacuum force due to the reduction in the diameter of the plunger 9 can be compensated for by the internal pressure of the tank 1. 9 can be reduced in diameter to increase the discharge pressure.

That is, according to this pressure intensifier, since the tank 1 of the conventional one-stage pressure intensifier is merely a closed tank and the branch pressure air path 28 is simply added, the number of parts can be relatively reduced. And the occurrence of failures can be reduced. Also,
It can be easily and inexpensively implemented with a simple configuration, and can be easily implemented by modifying an existing pressure booster.

Further, it is possible to perform low-pressure large-flow discharge and high-pressure small-flow discharge in accordance with the internal pressure of the load circuit 6.
For example, a large amount of pressure oil is discharged when the load circuit 6 is started up, so that the rise time of the load circuit can be reduced, and high pressure oil required for the load circuit 6 can be supplied. further,
Since the shortage of the vacuum force due to the reduction in the diameter of the plunger 9 can be compensated for by utilizing the internal pressure of the tank 1, the discharge pressure can be increased by reducing the diameter of the plunger 9.

In addition, when the internal pressure of the load circuit 6 reaches a predetermined value, the pneumatic driving device 3 and the pump 2 are automatically stopped, so that electrical control requiring an expensive control circuit and a control panel is not performed. In addition, energy is not wastefully consumed at the time of unloading, so that the cost is high. In addition, since the pressure oil passes through the closed circuit even in a flammable or explosive atmosphere, there is no need to take special measures for explosion or fire prevention, which is advantageous.

In the above embodiment, the branch pressure air passage 28 is
The branch pressure air passage 28 is formed outside the body 18 but can be formed in the body 18. In this case, the advantage that the external piping is simplified can be obtained. In the above embodiment, the hydraulic circuit in the pump 2 has the suction check valve 4, the pump chamber 5, and the discharge check valve 7 connected in series, but the hydraulic circuit in the pump 2 is connected in series. The pump chamber may be branched and connected between the suction check valve and the discharge check valve.

Further, another pressurized air supply means can be connected to the tank 1 as the precompression means.
Further, it is possible to provide a displaceable partitioning means such as a bellows, a diaphragm, a piston, etc. in the tongue 1 and a spring for urging the partitioning means in a certain direction. However, in order to simplify the configuration as a whole and to keep the internal pressure of the tank 1 constant during operation, as described above, the compressed air supply path for supplying compressed air of a predetermined pressure to the driving device is required. It is most advantageous to provide a branch pressure air passage for communicating the pressure to the tank.

[0038]

As described above, according to the pressure intensifier of the present invention, the tank accommodating the secondary pressure medium is constituted by a closed tank, and the preload means for increasing the internal pressure of this tank is provided. When the internal pressure of the load circuit is low, a secondary pressure medium with a low pressure and a large flow rate can be supplied to the load circuit using the pressure difference between the internal pressure of the load circuit and the internal pressure of the tank, and the internal pressure of the load circuit is higher than the internal pressure of the tank. Then, the secondary pressure medium having a high pressure and a small flow rate can be supplied to the load circuit by the action of the pump.

Further, for this purpose, the tank of the conventional one-stage pressure intensifier only needs to be a sealed tank and a preload means for increasing the internal pressure of the tank is provided, so that the number of parts can be relatively reduced, and failures can occur. In addition to being less likely to occur, the configuration can be simplified, and the present invention can be easily and inexpensively implemented, and the existing intensifier can be modified and easily implemented.

Further, since the shortage of the vacuum force in the pump chamber can be compensated for by the internal pressure of the tank, the diameter of the plunger can be reduced and the discharge pressure can be increased.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of the present invention at the start of a suction process.

FIG. 2 is an equivalent circuit diagram of one embodiment of the present invention.

FIG. 3 is an enlarged sectional view of the pneumatic driving device according to the embodiment of the present invention;

FIG. 4 is a cross-sectional view during a discharging process according to one embodiment of the present invention.

FIG. 5 is a cross-sectional view of the embodiment of the present invention at the end of the discharging process.

FIG. 6 is a cross-sectional view of the embodiment of the present invention at the start of the suction process.

FIG. 7 is a cross-sectional view during the inhalation process of one embodiment of the present invention.

FIG. 8 is a cross-sectional view of the embodiment of the present invention at the end of the suction process.

FIG. 9 is a circuit diagram of a conventional example.

FIG. 10 is an equivalent circuit diagram of a conventional example.

FIG. 11 is an equivalent circuit diagram of another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Tank 3 ... Pneumatic drive device 4 ... Suction check valve 5 ... Pump chamber 6 ... Load circuit 7 ... Discharge check valve 8 ... Piston 9 ... Plunger 13 ... Compressed air supply path 28 ... Branch pressure air path

Claims (1)

(57) [Scope of request for utility model registration] 1. A tank accommodating a secondary side pressure medium, a suction check valve, a pump chamber, a discharge check valve, and a load circuit are connected in series, and are made to protrude and retract into the pump chamber. In a pressure intensifier equipped with a pneumatic driving device for driving a plunger, the tank is constituted by a closed tank, and a branch pressure air passage for communicating a compressed air supply path for supplying compressed air of a predetermined pressure to the pneumatic driving device to the closed tank is provided. A pressure intensifier characterized by comprising: