JPH0115922Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is a pressure fluid power device, in particular, a pressure fluid is supplied into a cylinder, a piston in the cylinder is given reciprocating motion, and this reciprocating motion is performed by a hydraulic pump, hydraulic jack, or fork. The present invention relates to a pressure fluid power device used as a drive source for a lift.

Generally, this type of power device is
As shown in Publication No. 4890, a valve case is provided on one side of a cylinder divided into an atmospheric chamber and a pressure control chamber by a piston, and a spool valve is freely reciprocated in the valve case in the same direction as the piston. internally, the tip of the spool valve is opposed to the piston in the pressure control chamber, and the spool valve opens an exhaust passage formed in the valve box by forward movement of the spool valve, and closes it by backward movement. An exhaust valve is provided between the large-diameter rear chamber of the spool valve and the cylinder, the rear chamber is connected to the pressure control chamber at the forward movement position of the piston, and connected to the atmospheric chamber at the backward movement position of the piston. It has been proposed that a communication path is provided.

However, in the power plant disclosed in the above publication, even when the pressure fluid in the pressure control chamber is discharged, the pressure fluid continuously flows into the pressure control chamber through the pressure fluid supply passage. As a result, there is a problem that a significant loss of pressure fluid occurs, which leads to a drive loss, and when the piston moves back, the piston is directly connected to the spool valve. It is also possible that the vehicle collides with the vehicle, causing a collision sound and impact.

This invention was developed in view of the above circumstances.
The purpose is to simplify the pressure fluid supply and discharge path while being able to stop the supply of pressure fluid into the pressure control chamber when the pressure fluid in the pressure control chamber is discharged by forward movement of the spool valve. An object of the present invention is to provide a pressure fluid power device that can have a flexible configuration and further reduce driving noise.

Therefore, in the present invention, an exhaust passage for exhausting the pressure fluid in the pressure control chamber is formed in a valve box provided on one side of the cylinder, and an opening on the pressure control chamber side of the exhaust passage is arranged around the spool valve. At the same time, the spool valve is provided with an exhaust valve that opens an exhaust passage formed in the valve case by the forward movement of the spool valve and closes it by the return movement. An air supply passage is formed that is open at the tip and the other end is opened on the outer circumferential surface of the spool valve, and the spool valve is connected to the air supply passage only when the spool valve moves back. The present invention is characterized in that an air supply port is provided that is cut off from communicating with the air supply port when the valve moves forward, and a buffer member is provided on the surface of the piston that faces the spool valve.

Embodiments of the pressure fluid power device according to the present invention will be described below with reference to the drawings.

In the figure, 1 has a piston 2 inside that can freely reciprocate,
The cylinder is divided into an atmospheric chamber 4 and a pressure control chamber 3 by the piston 2, and a valve box 5 is provided on one side of the cylinder 1 and a pump casing 6 is provided on the other side.
The cylinder 1 is hermetically sealed by the valve box 5 and the pump casing 6.

A spool hole 7 consisting of a small diameter hole 7a and a large diameter hole 7b is bored in the center part of the valve case 5, and a spool valve 8 consisting of a spool body 8a and a large diameter part 8b is formed, so that the spool body 8a into the small diameter hole 7a, and the spool valve 8 is freely reciprocated in the same direction as the piston 2 so that the tip of the spool body 8a is exposed to the pressure control chamber 3 and faces the piston 2. Furthermore, an air supply passage 9 is formed in the axial center of the spool body 8a, extending in the axial direction and having one end opened at the tip of the spool body 8a, and the other end of the supply passage 9 is The spool body 8 is inserted into the spool body 8 through a small through hole 10 extending in the radial direction formed in the spool body 8a.
It is opened on the outer peripheral surface of a.

The valve box 5 also includes an air supply port 11 that communicates with the through hole 10 when the spool valve 8 moves forward, and an exhaust passage 12 that exhausts the pressure fluid in the pressure control chamber.
The opening of the exhaust passage 12 on the pressure control chamber 3 side is opened around the spool valve 8.

Further, an exhaust valve 13 is provided near the tip of the spool valve 8 on the pressure control chamber 3 side, and opens the exhaust passage 12 when the spool valve 8 moves forward and closes it when the spool valve 8 moves backward. An annular protrusion 13a is provided on the side of the valve case 5 to contact the side wall portion of the valve case 5 and maintain airtightness within the pressure control chamber 3.

Further, inside the atmospheric chamber 4 of the cylinder 1, a spring 14 is installed between the pump casing 6 and the piston 2 to urge the piston 2 toward the spool valve 8 and to move the piston 2 and the spool valve 8 back. That's what I do.

On the other hand, between the rear chamber 15 of the spool valve 8 in the valve case 5, that is, the rear chamber 15 of the large diameter portion 8b, and the cylinder 1, the pressure is A communication passage 16 is provided for communicating with the control chamber 3 and between the back chamber 15 and the atmospheric chamber 4 at the backward movement position of the piston 2, and the back chamber 15 is sealed by a lid 17. -ing

As described above, by providing the cut groove 18 at the tip of the spool valve 8 exposed to the pressure control chamber 3, the return movement position of the piston 2, that is, the tip of the piston 2 and the spool valve 8 are aligned. The pressure fluid (hereinafter referred to as compressed gas) sent from the air supply passage 9 is to flow into the pressure control chamber 3 through the kerf 18 while the tip of the
Furthermore, the spool valve 8 in the piston 2
A buffer member 19 is provided at the portion that comes into contact with the
A small diameter portion 20 is provided at the end of the piston 2 on the atmospheric chamber 4 side.
The communication passage 16 and the atmospheric chamber 4 are communicated with each other at the backward movement position of the piston 2.

In addition, a through hole 21 is provided in the side wall of the cylinder 1 on the atmospheric chamber 4 side, and furthermore, the pump casing 6 is opened by the back movement of the plunger 22 fixed to the piston 2 to open the valve body 24 and draw liquid into the pump casing 6. Suck the liquid into the barrel 23 from the port 25,
A liquid pump is formed in which the valve body 26 is opened by the forward movement of the plunger 22 and the liquid in the barrel 23 is discharged from the liquid discharge port 27.

Further, 28 in the figure indicates an O-ring.

The pressure fluid power device of the present invention has the above configuration, and its operation will be explained next.

First, the compressed gas sent from the air supply port 11 passes through the air supply passage 9 from the small through hole 10, and is sent into the pressure control chamber 3 via the kerf 18.

The compressed gas sent into the pressure control chamber 3 causes the piston 2 to move toward the pump casing 6 against the biasing force of the spring 14, as shown in FIG.

Due to this forward movement, the plunger 22 fixed to the piston 2 moves forward within the barrel 23, pressurizing the liquid within the barrel 23, and the liquid is transferred to the valve body 2.
6 is pushed open and the liquid is discharged from the liquid discharge port 27.

When the piston 2 further moves forward and the side wall of the piston 2 on the pressure control chamber 3 side faces the end of the communication passage 16 connected to the cylinder 1, that is, the piston 2 moves as shown in FIG. When the position is reached, the high pressure compressed gas in the pressure control chamber 3 flows into the back chamber 15 through the communication passage 16, and this compressed gas causes the valve body 8 in the spool valve 8 to
By pushing a, the spool valve 8 is moved toward the pressure control chamber 3 side.

By this forward movement of the spool valve 8, the air supply passage 9 is blocked and the flow of the compressed gas into the pressure control chamber 3 is stopped. The closed exhaust passage 12 is opened by the reciprocating movement of the spool valve 8, and the compressed gas in the pressure control chamber 3 is discharged to the outside through the exhaust passage 12, and the piston 2 is moved toward the spring. The spool valve 8 is moved back by the urging force of the piston 14, and the spool valve 8 is moved back at the tip of the piston 2 due to the back movement of the piston 2.

By this return movement of the spool valve 8, the air supply passage 9 communicates with the pressure control chamber 3, and the exhaust passage 12 is closed by the exhaust valve 13 provided on the spool valve 8, so that the pressure Compressed gas flows into the control chamber 3 and the piston 2
The reciprocating motion is performed continuously.

Incidentally, when the spool valve 8 moves back, the back chamber 1
Since the pressurized gas in the spool valve 5 flows into the atmospheric chamber 4 through the communication passage 16, the spool valve 8 is reliably moved back.

When the piston 2 moves back, the plunger 22 moves back inside the barrel 23, causing the barrel 23 to move back.
The internal pressure becomes negative, the valve body 24 opens, and the liquid inlet 2
5 into the barrel 23.

In the embodiment, an example is shown in which the reciprocating motion of the plunger 22 fixed to the piston 2 is used as a liquid pump, but it may also be used as a drive source for other equipment, such as a hydraulic jack or a lift of a forklift.

As explained above, the present invention provides a valve case on one side of a cylinder divided into an atmospheric chamber and a pressure control chamber by a piston, and a spool valve is installed in the valve case so that it can freely reciprocate in the same direction as the piston. The tip of the spool valve is arranged to face the piston within the pressure control chamber, and the rear chamber is placed between the large diameter rear chamber of the spool valve and the cylinder at the forward movement position of the piston. In a pressure fluid power device having a communication passage communicating with a pressure control chamber and communicating with the atmospheric chamber at a return position, an exhaust passage for discharging the pressure fluid in the pressure control chamber is formed in the valve case, and The pressure control chamber side opening of the exhaust passage is opened around the spool valve, and the spool valve is provided with an exhaust valve that opens an exhaust passage formed in the valve box by forward movement of the spool valve and closes it by backward movement. , an air supply passage is formed in the axial center of the spool valve, one end of which opens at the tip of the spool valve, and the other end of which opens at the outer circumferential surface of the spool valve; Since an air supply port is provided that communicates with the air supply passage only when the spool valve moves backward, and is cut off from communication with the air supply port when the spool valve moves forward,
Of course, when the pressure fluid in the pressure control chamber is discharged by forward movement of the spool valve, the supply of compressed fluid into the pressure control chamber can be stopped to reliably prevent loss of compressed fluid. Since the air supply passage for the compressed fluid is provided in the axial center of the spool valve, there is no need to detour the air supply passage even if the exhaust passage for the compressed fluid is opened around the spool valve. The passage configuration of the passage can be simplified, and sealing means for preventing compressed fluid from leaking to the outside only needs to be provided at the connecting portion between the air supply passage and the air supply port, and therefore the device The overall structure and processing steps can be simplified.

Further, according to the present invention, since a buffer member is provided on the surface of the piston facing the spool valve, when the piston moves back, the piston does not directly collide with the spool valve. This made it possible to suppress noise generation during driving.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view showing an embodiment of the pressure fluid power device according to the present invention, and FIGS. 2 to 4 are longitudinal sectional front views showing the operating state of the device. DESCRIPTION OF SYMBOLS 1... Cylinder, 2... Piston, 3... Pressure control chamber, 4... Atmospheric chamber, 5... Valve box, 8... Spool valve, 9... Air supply passage, 11... Air supply port, 12
...Exhaust hole, 13...Exhaust valve, 14...Spring.

Claims (1)

[Scope of utility model registration request] A piston is installed inside the cylinder so that it can freely reciprocate, a valve box is provided on one side of the cylinder which is divided into an atmospheric chamber and a pressure control chamber by the piston, and a spool valve is installed in the valve box so that it can freely reciprocate in the same direction as the piston. internally, the tip of the spool valve is arranged to face the piston within the pressure control chamber, and the rear chamber is located between the large diameter rear chamber of the spool valve and the cylinder, so that the rear chamber is located at the forward movement position of the piston. In the pressurized fluid power device, the pressure fluid power device is provided with a communication passage that communicates with the pressure control chamber at a position and communicates with the atmospheric chamber at a return position, wherein an exhaust passage is formed in the valve box to exhaust the pressure fluid in the pressure control chamber. , the pressure control chamber side opening of the exhaust passage is opened around the spool valve, and the spool valve is provided with an exhaust valve that opens an exhaust passage formed in the valve box by forward movement of the spool valve and closes it by backward movement. forming an air supply passage in the axial center of the spool valve, one end of which opens at the tip of the spool valve, and the other end of which opens at the outer peripheral surface of the spool valve;
The valve case is provided with an air supply port that communicates with the air supply passage only when the spool valve moves backward, and communication with the air supply port is cut off when the spool valve moves forward; A pressure fluid power device characterized in that a buffer member is provided on a surface facing the spool valve.