JPS63212781A - Directional selector valve in double acting pneumatically operated hydraulic pump - Google Patents

Abstract

PURPOSE:To make the structure compact, by connecting one of second passages with a third passage through one of annular grooves formed on a spool valve, and connecting a first passage with the other second passage through a elongated hole. CONSTITUTION:When a spool valve 24 is moved to a right stroke end, a second passage 34a is connected through an annular groove 28a to a third passage 36a, thereby controlling a nonpressure air. When the spool valve 24 is moved to a left stroke end, a pressure air is allowed to flow through an elongated hole 26 and the second passage 34a to a left cylinder chamber 6a. Thus, a charging direction of the pressure air and a discharging direction of the non- pressure air can be selected by a single spool valve.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a directional valve in a double-acting pneumatically operated hydraulic pump operated by the action of air pressure.

In this specification, "pressure air" refers to air that maintains a predetermined pressure and does not communicate with the atmosphere.
"Unpressurized air" refers to air that communicates with the atmosphere.

[Conventional technology]

Pneumatically actuated hydraulic pumps are operated by air pressure rather than electric motors, so they can be used as a drive source for hydraulic equipment in paint factories, fireworks factories, etc. where there is a risk of explosion due to ignition, or as emergency pumps in emergencies such as power outages. It is widely used as a drive source for hydraulic equipment.

A double-acting pneumatically operated hydraulic pump requires a directional control valve for alternately feeding pressurized air into the left and right cylinder chambers and alternately discharging unpressurized air from the left and right cylinder chambers into the atmosphere.

[Problem that the invention seeks to solve]

Two spool valves are usually required to switch the direction of pressurized air inlet and the unpressurized air outlet direction of a double-acting pneumatically operated hydraulic pump using a directional control valve using spool valves.

The present invention has been made for the purpose of enabling each of the above-described switching operations to be performed using a single spool valve.

[Means for solving problems]

The present invention provides a through-hole with a length corresponding to the stroke of the spool valve in the center of the spool valve, an annular groove at both ends, and a pressurized air source in the longitudinal center of the valve chamber. A first passage leading to the pump is connected to the valve chamber, and two second passages leading to the cylinder chamber of the pump are located on both sides of the first passage and connected to a portion facing the first passage with respect to the valve chamber. A third passage leading to the atmosphere is connected to a portion of the valve chamber at the same position as the second passage along the length of the valve chamber so as to be substantially orthogonal to the second passage, and the rotation of the spool valve is The gist of this invention is that a guide rod is inserted into the elongated through hole to prevent this.

[Action of the invention]

By connecting the second passage and the third passage through the annular groove on one side of the spool valve at the left and right stroke ends of the spool valve, the unpressurized air in one cylinder chamber of the pump is brought into the atmosphere. At the same time, the first passage and the other second passage are connected through the long through hole of the spool valve, so that the pressurized air from the pressurized air source is sent into the other cylinder chamber.

〔Example〕

Embodiments of the invention are shown in FIGS. 1-11.

The double-acting pneumatic hydraulic pump according to the present invention is comprised of a pump A and a directional valve B.

First, pump A will be explained with reference to FIGS. 1 to 7. A piston 4 is provided inside the cylinder 2, and the cylinder chamber is partitioned by the piston 4 into a left cylinder chamber 6a and a right cylinder chamber 6b. so that the plunger 8 is attached to both sides of the piston 4,
A plunger 8 is integrally attached to the piston 4 by a pin lO.

A left oil chamber 12a is provided on both sides of the left and right cylinder chambers 6a and 6b.
A right oil chamber 12b is provided, and the oil in the left and right oil chambers 12a, 12b is alternately compressed and discharged by the reciprocating movement of the piston 4, or the oil in the tank 14 is alternately compressed and discharged into the left and right oil chambers 12a, 12b. It's like you're being sucked into it. An annular groove 16 having a predetermined width is provided in the central outer circumference of the piston 4. This annular groove 16 constitutes a passage for discharging unpressurized air in a valve chamber 22 of a directional control valve B, which will be described later, into the atmosphere.

Two types of pilot boats 18a118b for detecting that the piston 4 has reached both stroke ends are opened into the left and right cylinder chambers 6a, 6b. The pilot boats 18a and 18b each have a piston 4
This is a boat for detecting when the stroke reaches the right stroke end and the left stroke end. When the piston 4 is located in the center, both pilot ports 18a and 18b are closed by the piston 4, but when the piston 4 reaches the left stroke end as shown in FIG. 18b opens and communicates with the right end of the valve chamber 22 of the spool valve 24, and when the piston 4 reaches the right stroke end as shown in FIG. It leads to the left end of the

Next, the direction switching valve B for switching the direction of pressurized air sent into the left and right cylinder chambers 6a, 6b will be explained.

A spool valve 24 is slidably housed in a valve chamber 22 provided in the valve body 20. As shown in FIG. 5, this spool valve 24 is provided with a through hole 26 in the center with a length corresponding to the stroke of the spool valve 24, and annular grooves 28a and 28b in both ends. These are the configurations provided respectively.

A first passage 32 communicating with a pressure air source is connected to the central portion of the valve chamber 22 in the longitudinal direction via a joint 30.
The passage 32 is provided perpendicularly to the valve body 20 above the valve chamber 22. Two second passages 34a, 34b are connected to a portion of the valve chamber 22 facing the first passage 32, and the second passages 34a, 34b are connected to the first passage 32.
In contrast, the distribution is arranged in a shape. Second passage 34
a, 34b are the valve chamber 22 and the left and right cylinder chambers 6as6b
It is a passageway to connect the

Third passages 36a, 36b communicating with the atmosphere are connected to parts of the valve chamber 22 at the same positions as the second passages 34a, 34b along the length direction of the valve chamber 22, and the third passages 36a, 36b communicate with the atmosphere. The connecting portions of No. 3 to the passages 36a and 36b are horizontal (see FIGS. 6 and 10).

Both left and right ends of the valve chamber 22 are connected to the pilot port 18a118b via fourth passages ysa and a8b, respectively.

Therefore, as shown in FIG. 1, when the spool valve 24 moves to the right stroke end, the second passage 34a and the third passage 36a are connected via the annular groove 28a (see FIG. 6), and As shown in FIG. 2, when the spool valve 24 moves to the left stroke end, the second
The passage 34b and the third passage 36b are connected (the first
(See figure 0).

In addition, as shown in FIGS. 1 and 3, the valve body 20
A fifth passage 40 connecting the annular groove 16 of the piston 4 and the valve chamber 22 is vertically provided in the center of the piston 4, and a guide member 42 is installed inside the fifth passage 40 to form the fifth passage. 40 and the valve chamber 22, and the guide member 4
A guide rod 42a protruding from the tip of the guide rod 42a is inserted into the elongated through hole 26 of the spool valve 24, thereby preventing the spool valve 24 from rotating. Fifth passage 40
and a sixth passage 44 communicating with the atmosphere,
The non-pressurized air in the valve chamber 22 flows through the fourth passage 38a, the pilot boat 18a (or the fourth passage 38b, the pilot port 18b), the annular groove 16, the fifth passage 40, and the sixth passage 38a.
The air is discharged into the atmosphere through a passageway 44.

Next, the operation of the directional control valve B will be explained.

In FIGS. 1 and 2, "pressure air" is indicated by a dashed line hatching at the upper left, "non-pressure air" is indicated by a broken line hatching at the upper right, and "oil" is indicated by a set of dots.

When the spool valve 24 is located at the right stroke end, the pressurized air that flows in from the joint 30 passes through the elongated hole 26 of the spool valve 24 and the second passage 34b, flows into the right cylinder chamber 6b, and also flows into the left cylinder chamber. The unpressurized air in 6a flows through the second passage 34a and the annular groove 2 of the spool valve 24.
8a and into the atmosphere through the third passage 36a;
Pressure air acts on the pressure receiving surface on the right side of the piston 4, and the piston 4 moves to the left. As the piston 4 moves to the left, the oil in the left oil chamber 12a is compressed and discharged by the plunger 8, and the right oil chamber 12b becomes a negative pressure and oil is sucked in from the tank 14.

When the piston 4 reaches the left stroke end as shown in FIG.
b into the right end of the valve chamber 22, and the valve chamber 2
The unpressurized air at the left end of the second
is discharged into the atmosphere through passage 44, causing spool valve 24 to move to the left as shown in FIG.

When the spool valve 24 reaches the left stroke end, pressurized air flows into the left cylinder chamber 6a through the elongated through hole 26 and the second passage 34a, and the non-pressure air in the right cylinder chamber 6b flows into the second passage 34a. It is discharged into the atmosphere through the passage 34b, the annular groove 28b of the spool valve 24, and the third passage 36b. As a result, pressurized air acts on the left pressure receiving surface of the piston 4, causing the piston 4 to move to the right.Contrary to the above, the oil in the right oil chamber l2b is compressed and discharged by the plunger 8, and the oil in the left oil chamber l2b is compressed and discharged. The oil chamber 12a becomes negative pressure and the tank 14
Oil is sucked in from.

When the piston 4 reaches the right stroke end as shown in FIG. 2, the pilot boat 18a and the fourth passage 38
Pressure air enters the left end of the valve chamber 22 through a, and unpressurized air at the right end of the valve chamber 22 is released into the atmosphere, so that the spool valve 24 moves to the right as shown in FIG. The pressurized air flows into the cloth cylinder chamber 6b again, and the non-pressure air in the left cylinder chamber 6a is discharged into the atmosphere.

〔Effect of the invention〕

According to the present invention, it is possible to switch between the feeding direction of pressurized air and the discharging direction of non-pressurized air of the double-acting pneumatically operated hydraulic pump using a directional switching valve using one spool valve.

[Brief explanation of the drawing]

1 and 2 are diagrams showing the state immediately after the piston 4 reaches the left and right stroke ends, respectively, and FIG.
Figure XX! ! 4 is a sectional view of the directional control valve B in a state immediately after the piston 4 reaches the left stroke end, FIG. 5 is a perspective view of the spool valve 24, and FIGS. 6 and 7 are: Y-Y line sectional view and Z-Z in Fig. 4, respectively.
8 is a sectional view of the directional control valve B in a state where the spool valve 24 has moved to the left after the piston 4 has reached the left stroke end, and FIGS. The cross-sectional view along the Y'-Y' line and the cross-sectional view along the Zo-Z' line in FIG. FIG. The explanation of the symbols of the main parts is as follows. A: Pump B: Directional switching valve 6a: Left cylinder chamber 6b: Right cylinder chamber 20: Valve body 22; Valve chamber 24 Nispool valve 26: Through-holes 28a, 28b; Spool valve annular groove 32: First passage 34a , 34b: Second passage 35a, 36b: Third passage 42a: Guide Rondo

Claims (1)

[Claims] A long through hole with a length corresponding to the stroke of the spool valve is provided in the center of the spool valve, an annular groove is provided in both ends, and a first hole communicating with a pressure air source is provided in the longitudinal center of the valve chamber. two second passages leading to the cylinder chamber of the pump are located on both sides of the first passage and are connected to the part facing the first passage with respect to the valve chamber. In order to prevent rotation of the spool valve by connecting a third passage leading to the atmosphere to the same position as the second passage along the length of the valve chamber so as to be substantially perpendicular to the second passage. A guide rod is inserted into the elongated through hole, and the second passage and the third passage are connected through one annular groove of the spool valve at the left and right stroke ends, and the through length of the spool valve is 1. A directional control valve for a double-acting pneumatically operated hydraulic pump, characterized in that the first passage and the other second passage are connected to each other through a hole.