JPS59754B2 - Hydraulic pilot type switching valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a hydraulic pilot type switching valve that eliminates time lag during operation.

[Technical background of the invention]

In general, a type of hydraulic pilot type switching valve in which the hydraulic switching valve is operated by operating a pilot valve (Hydraulic Technology Handbook, Hydraulic Technology Handbook Editorial Committee Line, published by Nikkan Kogyo Shinkaisha on April 15, 1962, page 362) (See pages 365 to 365)
In this case, a hydraulic oil chamber for selectively moving the plunger to the left or right is provided at both the left and right ends of the plunger, and pilot hydraulic pressure from a pilot valve is supplied to or discharged from the hydraulic oil chamber. That's what I do.

That is, the hydraulic pilot type switching valve 1 includes a valve housing 2 and a switching plunger 3, as shown in FIG. ) and a pressure oil source (not shown) are drilled therein, and the switching plunger 3 is provided with pressure oil passages 2b, etc., which are selectively connected to a pressure oil source (not shown), and the switching plunger 3 is provided with a pressure oil passage 2b, etc., which connects or blocks the aforementioned flow passages 2a and 2b. A plurality of openings 3a5 and passages 3b are provided respectively.

Furthermore, a spool 4 is integrally provided at both ends of the plunger 3 and extends outward from the lugs 2.

A cover 5 surrounding the spool 4 is attached to the outside of both measuring portions of the housing 2, and a hydraulic oil chamber 6 is formed by the cover 5 and the outer surface of the housing 2.

A spring receiver 7 is loosely fitted to the outermost end of each spool 4, a spring receiver 8 is fixed slightly inwardly of the spring receiver 7, and a coil spring 9 is provided between both spring receivers.

10 is a small hole bored in the spring receiver 7, and when the plunger 3 moves and the outer end of the spring receiver 7 collides with the inner wall surface of the cover 5, a small hole 10 is formed in the inner surface of the spring receiver 7. The plunger 3 is buffered by causing the accumulated oil to flow out from the small hole 10 into the chamber 6.

Each cover 5 is provided with a pilot oil pressure display plate 14 for communicating the internal hydraulic oil chamber 6 with an oil pipe 12, 13 from the pilot valve 11.

In the switching valve having such a structure, when the pilot valve 11 is operated to selectively supply pressure oil to either the oil pipe 12 or 13, the plunger 3 moves to the left or right from the neutral position shown in the figure. However, the function of selectively communicating or blocking the flow paths 2a and 2b is performed.

[Problems with background technology]

However, in the above-mentioned type of hydraulic pilot operated switching valve, a relatively small diameter pipe is generally used as the pilot hydraulic pressure supply pipe from the pilot valve to the hydraulic oil chamber due to installation space and cost considerations. This is done through a small diameter pipe that drains the oil from the oil chamber.

Furthermore, the length of the piping becomes relatively long.

Therefore, the oil drain pipe (also used as a supply pipe) for draining oil from the hydraulic oil chamber on the opposite side of the hydraulic oil chamber (hydraulic oil chamber in non-operating state) where the plunger is being actively moved in response to the pilot oil pressure is supplied. ) due to its small diameter, it will be carried out gradually, creating resistance to rapid movement of the plunger.

As a result, a time lag occurs in the operation of the switching valve, resulting in inconveniences such as a rapid and timely switching operation cannot be expected.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned points, and the spool is operated by a minute change in pilot oil pressure to supply and discharge oil to the hydraulic oil chamber, thereby eliminating the time lag of the plunger caused by the pilot oil pressure. The purpose of this invention is to provide a type switching valve.

[Summary of the Invention] The present invention provides a pilot hydraulic pressure supply hole connected to an oil pipe adjacent to a hydraulic oil chamber provided at both ends of a switching plunger slidably attached to a valve/Ujilug, and a pilot hydraulic pressure supply hole connected to an oil pipe. , spaced apart in the axial direction of the hydraulic supply hole,
Two passages are provided to connect to the hydraulic oil chamber, and
A passage connected to the oil tank is opened, and the pilot oil pressure supply hole is actuated by the pilot oil pressure, and one passage is opened to allow communication between the pilot oil pressure supply hole and the hydraulic oil chamber, and the other passage and the oil tank are connected to each other. A spring-loaded spool is provided to close the communication between the two passages, and the spool, which is moved by pilot oil pressure, selectively connects and disconnects the two passages with the hydraulic oil chamber.

[Embodiments of the invention]

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

In FIG. 2, the same members as those in FIG. 1 are designated by the same reference numerals, and their explanations will be omitted.

In FIG. 2, a pilot hydraulic pressure supply hole 14 to which an oil pipe 12 or 13 is connected is bored in the longitudinal direction of the cover 5, and is biased outwardly by a spring 16. A spool 17 is slidably fitted therein.

Furthermore, two passages 18 and 19 that communicate the hydraulic oil chamber 6 and the pilot oil pressure supply hole 14 are bored in the cover 5 at intervals in the axial direction of the oil pressure supply hole under the following conditions. ing.

That is, the pilot oil pressure supply hole 14 is open at one end, and the passage 18 is provided at a portion corresponding to the spring support provided at the closed end of the pilot oil pressure supply hole 14.

Therefore, the passage 18 is in a position where it is not closed by the spool 17 even if the spool 17 slides along the pilot oil pressure supply hole 14.

On the other hand, the passage 19 is provided at a distance greater than the length of the spool 17 from the passage 18, and is set to open when the spool 17 comes into contact with the spring support due to pilot oil pressure.

Further, a passage 20 is provided between the passage 18 and the passage 19 of the cover 5 and in a portion close to the passage 18, which communicates with the pilot oil pressure supply hole 14 and an oil tank (not shown).
This passage 20 closes when the spool 17 abuts the spring support, while the passage 19 opens, and opens when the spool 17 is biased by the spring 16 and moves away from the spring support. It is located in such a position that the border passage 19 is closed.

Next, the operation of this device will be explained.

A case is assumed in which pilot oil pressure is supplied from the pilot valve 11 to the pilot oil pressure supply hole 14 through the pipe line 12 in the right hydraulic oil chamber.

The pilot oil pressure from the pipe 12 flows into the pilot oil pressure supply hole 14 of the right cover 5, and moves the spool 17 inward (to the left in the drawing) against the spring 16.

When the spool 17 moves to the left and the passage 20 is closed by the spool 17, the passage 19 opens and the pilot oil pressure supply hole and the hydraulic oil chamber 6 communicate with each other, and the pilot oil pressure from the pipe line 12 is transferred to the hydraulic oil chamber 6 on the right side. and presses the right end side of the spool 4 toward the left.

On the other hand, at this time, the hydraulic oil chamber on the left side of the switching valve, 6' (for convenience of explanation below, each member of the left hydraulic oil chamber is marked with "'",
(distinguished from the member on the right), the pilot oil pressure supply hole 14' is connected to the oil tank (not shown) via the pipe 13 and the pilot valve 11, so the hydraulic oil chamber 6' is
communicates with passage 20' via passage 18';
The oil in the hydraulic oil chamber 6' is in a state where it can freely return to the oil tank without encountering any resistance.

Therefore, when the plunger 3 moves to the left by supplying pilot oil pressure to the right side hydraulic oil chamber 6, the oil in the left side hydraulic oil chamber 6' returns to the oil tank without interfering with the movement of the plunger at all. The plunger can be moved extremely quickly and smoothly, and the switching valve can be operated without any time lag.

On the other hand, if the pilot valve 11 is switched to supply pilot oil pressure to the pipe line 13 and communicate the pipe line 12 to the oil tank, the spool 17 connected to the right hydraulic oil chamber 6
The passage 18 is moved to the right by the spring 16 and communicates with the passage 20, so that the hydraulic oil chamber 6 directly communicates with the oil tank.

Therefore, the plunger 3 is moved to the right very rapidly by the hydraulic pressure applied to the left in the same manner as described above, and the plunger 3 can be moved to the right without any time lag.

In addition, in the above embodiment, the passage 20 is used as the return passage 2 of the switching valve.
Of course, if the oil tank is connected directly to a, the hose provided between the passage 20 and the oil tank can be omitted.

[Results of the invention]

As described above, according to the present invention, the spool provided in the pilot oil pressure supply hole is moved by minute changes in pilot oil pressure to supply oil to the hydraulic oil chamber and to discharge oil from the hydraulic oil chamber. Therefore, the discharge speed can be significantly increased compared to the conventional pilot oil pipe, and the time lag of the plunger due to the pilot oil pressure can be reduced to 1/10 to 1/1 compared to the conventional oil drain of this type.
/50, that is, the time lag can be brought to a state close to zero, and the effect is that rapid and timely switching operations can be performed.

[Brief explanation of drawings]

FIG. 1 is a sectional view schematically showing a conventional hydraulic pilot type switching valve, and FIG. 2 is a sectional view of a main part of the hydraulic pilot type switching valve of the present invention. 2... Valve housing, 3... Plunger, 6... Hydraulic oil chamber, 11... Pilot valve, 12, 13... Operation Oil pipe line, 14...
... Pilot oil pressure supply hole, 16 ... Coil spring, 17 ... Spool, 18° 19.20
······aisle.

Claims (1)

[Claims] 1 having a valve housing, a switching plunger slidably attached to the housing, and hydraulic oil chambers disposed at both ends of the switching plunger to operate the plunger;
In the hydraulic pilot type switching valve, a pilot hydraulic pressure supply hole connected to the oil pipe is provided adjacent to each of the hydraulic oil chambers, and two passages are provided in the pilot hydraulic pressure supply hole at intervals in the axial direction of the hydraulic pressure supply hole. is connected to the hydraulic oil chamber, and a passage connected to the oil tank is opened, and the pilot oil pressure supply hole is operated by the pilot oil pressure, and one passage is opened to connect the pilot oil pressure supply hole and the operation A hydraulic pilot type switching valve characterized by being provided with a spring-loaded spool that communicates with an oil chamber and tightly closes communication between the other passage and an oil tank.