JPH0211668Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention includes, for example, a pair of circuit systems,
The present invention relates to a manual directional control valve that is optimal for controlling the merging of discharged oil from both pumps in a construction vehicle or the like in which a pump is connected to each of the two circuit systems.

(Prior Art) The conventional directional control valve shown in FIG. 2 has one end of the spool 1 installed inside the valve body H protruding outward from the main body H, and the projecting end is not shown in the figure. The spool 1 is switched by connecting a control lever and manually operating the control lever.

Further, a cap 3 whose outer end is closed with a plug 2 is provided on the other side of the valve body H, that is, on the side opposite to the side from which the spool 1 is projected.
The other end of the spool 1 projects into the cap 3, and a pair of spring receivers 4 and 5 are slidably fitted into this projecting end.

A return spring 6 is interposed between the spring receivers 4 and 5, and the action of the return spring 6 brings the spring receivers 4 and 5 into pressure contact with the side surfaces of the plug 2 and the valve body H, keeping the spool 1 in the neutral position. Trying to hold it in place.

The protruding portion of the spool 1 is made hollow, and a compression spring 8 is inserted into the hollow portion 7, and the protruding portion is slidably protruded into the plug 2.

The tip of the spring 8 is provided with a ball 9 that can freely roll within the hollow portion 7, and a pair of small diameter balls 10 and 11 are provided outside of the ball 9.

The small-diameter balls 10 and 11 have a portion protruding outward from the spool 1, and the plug 2
The control hole 12 is brought into contact with the peripheral surface of the control hole 12 formed in the control hole 12 .
This control hole 12 has a large diameter portion 12a in its central portion.
When the balls 10 and 11 move from the large diameter part 12a to either of the small diameter parts 12b, they are pushed along the small diameter part 12b, and the balls 9 are compressed by the compression spring 8.
move against.

That is, the balls 10 and 11 are connected to the large diameter portion 12a.
Compared to the sliding resistance of the spool 1 when the spool 1 is located at the small diameter portion 12b, the sliding resistance is greater when the spool 1 is located at the small diameter portion 12b.

Therefore, for example, a pair of circuit systems is provided,
In a construction vehicle or the like in which a pump is connected to each of these circuit systems, when controlling the merging of the oil discharged from both pumps, the balls 10 and 11 are positioned in the small diameter portion 12b, and when merging control is not required, By locating the balls 10, 11 in the large diameter portion 12a, the operating force can be changed. By changing the operating force in this manner, the feeling during the merging operation can be identified and erroneous operations can be avoided.

(Problem to be solved by the present invention) In the conventional directional control valve as described above, since the three balls 9 to 11 are used, the friction becomes too large, and the concentric accuracy etc. In the past, there was a drawback that variations occurred in the friction.

The purpose of this invention is to provide a manual directional control valve that uses a plurality of parallel springs to change the operating force and eliminates the above-mentioned drawbacks of the conventional valve.

(Means for Solving the Problem) This invention has one end of the spool protrude from the valve body, an operating lever is provided at the protruding end, and an end opposite to the operating lever protrudes into the cap, so that the spool can be This is based on a manual directional switching valve that changes its operating force depending on the amount of switching.

Based on the above-mentioned manual directional control valve, this invention forms a pair of first stage parts on the spool in the cap with a predetermined interval maintained, and both of these first stage parts serve as a stopper for one-way sliding. A pair of first spring receivers are slidably fitted onto the spool, and a return spring is interposed between these first spring receivers, while a pair of second step portions are provided inside the space between the two first step portions. A pair of second spring bearings having both second step portions used as stoppers for one-way sliding are slidably fitted to the spool, and an auxiliary spring is interposed between these second spring bearings. , is characterized in that the auxiliary spring and the return spring are arranged in parallel.

(Operation of the present invention) Since the present invention is constructed as described above, when the spool is moved to either the left or right, only the return spring is compressed if the movement stroke is small. Therefore, the operating force on the spool in this case is equal to the spring force of the return spring.

Then, after the stroke of the spool increases and the second spring receiver comes into contact with the first spring receiver, both the return spring and the auxiliary spring are compressed at the same time. Therefore, the operating force of the spool in this case is equal to the sum of the spring forces of both springs.

In other words, the operating force changes depending on the stroke of the spool.

(Embodiment of the present invention) The embodiment of the present invention shown in FIG. 1 is similar to the conventional valve body in that a cap 3 is provided on the valve body H, and one end of the spool 1 is made to protrude into the cap 3.

A pair of first step portions 1 are provided on both end sides of the protruding portion.
3 and 14, and these step portions 13,
First spring receivers 15 and 16 are slidably fitted between the first spring receivers 14 and 14. A pair of first spring receivers 1 thus constructed
When the spool 1 moves leftward in the drawing, one of the first spring receivers 15 of the spring receivers 5 and 16 is connected to the first step portion 1.
3 as a stopper, and the other first spring receiver 16 is
When the spool 1 moves rightward in the drawing, the first step portion 14 serves as a stopper. Therefore, if spool 1 moves to the left in the drawing, the first
The spring receiver 15 moves together with the spool, and when the spool moves rightward, the first spring receiver 16 moves together with the spool.

Note that when the spool 1 is in the neutral position shown, one first spring receiver 15 is in contact with the valve body H, and the other first spring receiver 16 is in contact with the cap 3.

A return spring 17 is interposed between the first spring receivers 15 and 16, and the action of the return spring 17 normally maintains the spool 1 at a neutral position.

Further, a cylindrical body 18 is fitted to one of the first step parts 13 side of the first step part, and one end thereof is brought into contact with the first step part 13, and the one first spring receiver 15 is brought into contact with the first step part 13.
can slide on the outside of this cylindrical body 18. The cylindrical body 18 configured in this manner has one second step portion 19 as a step between the spool 1 and the end opposite to the first step portion 13 . Furthermore, the first
The other second step portion 20 is formed closer to the other first step portion 14 of the step portions. A second spring receiver 21,
22 are slidably fitted.

Of the pair of second spring receivers 21 and 22 configured in this way, one second spring receiver 21 uses the second step portion 19 as a stopper when the spool 1 moves to the left in the drawing, and the other second spring receiver 21 uses the second step portion 19 as a stopper. The receiver 22 is the spool 1
When the second step portion 20 moves to the right in the drawing, the second step portion 20 becomes a stopper. Therefore, if the spool 1 moves to the left in the drawing, the second spring receiver 21
moves together with the spool, and if the spool moves rightward, the second spring receiver 22 moves together with the spool.

An auxiliary spring 23 is interposed between the second spring receivers 21 and 22.

Next, the operation of this embodiment will be explained.

Now, if the spool 1 is moved from the illustrated neutral position to the left in the drawing, both the first spring receiver 15 and the second spring receiver 21 will first move.
It moves integrally with the spool 1 while being caught on the first step part 13 and the second step part 19.

At this time, the first spring receiver 1 in contact with the cap 3
6 remains in contact with the cap 3 and does not move. However, the moving force of one second spring receiver 21 acts on the other second spring receiver 22 via the auxiliary spring 23 . Therefore, the other second spring receiver 22 moves until it comes into contact with the other first spring receiver 16.

Therefore, until the other second spring receiver 22 hits the other first spring receiver 16, the auxiliary spring 23 does not deflect, and only the return spring 17 deflects. Therefore, the operating force of spool 1 is
It is sufficient that a force sufficient to overcome the spring force of the return spring 17 acts.

After the other second spring receiver 22 hits the other first spring receiver 16, the auxiliary spring 23 is pushed by one of the second spring receivers 21 and is compressed.

That is, until the stroke of the spool 1 is small and the other second spring receiver 22 hits the other first spring receiver 16, the operating force on the spool 1 is determined only by the spring force of the return spring 17. However, after the stroke of the spool 1 increases and the second spring receiver 22 hits the first spring receiver 16, the operating force applied to the spool 1 becomes the sum of the spring forces of both springs 17 and 23. Therefore, when the stroke of the spool 1 is large, the operating force on the spool 1 is greater than when the stroke of the spool 1 is small.

In addition, even when the spool 1 is moved to the right in the opposite direction to the above, when the movement stroke is small, the operating force is small, and when the stroke exceeds a certain level, the operating force becomes large. It is.

(Effects of the present invention) Since this invention is constructed as described above, the friction can be made smaller than in the conventional case where the ball is brought into pressure contact with the circumferential surface of the control hole, and the operating force can be reduced accordingly. will improve. Furthermore, since the structure is simple, maintenance is also easy.

Furthermore, since the return spring and the auxiliary spring are arranged in parallel, the overall length can be made shorter than when they are arranged in series. If the part where the spring is placed becomes long, that part must be specially supported by another member. However, if you try to support it with separate members like this, the number of structural parts will increase accordingly, and if you do not accurately determine the concentricity of each support part,
The spool does not move smoothly. Therefore, accuracy is required for concentric machining, which increases the number of manufacturing steps.

However, if both springs are arranged in parallel as in this invention, there is an advantage that the above problem does not arise at all.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the main parts showing an embodiment of this invention.
FIG. 2 is a sectional view of a conventional main part. H... Valve body, 1... Spool, 3... Cap, 13, 14... First stage section, 15, 16...
...First spring holder, 17...Return spring, 1
8... Cylindrical body, 19, 20... Second stage part, 21, 2
2...Second spring holder, 23...Auxiliary spring.

Claims (1)

[Scope of utility model registration request] A manual valve in which one end of the spool protrudes from the valve body, an operating lever is provided at the protruding end, and the opposite end of the operating lever protrudes into the cap, and the operating force is varied according to the switching amount of the spool. In the directional control valve, a pair of first step portions are formed at a predetermined interval on the spool in the cap, and a pair of first spring receivers are provided with the first step portions serving as stoppers for one-way sliding. The spool is slidably fitted into the spool, and a return spring is interposed between these first spring receivers, while both first
A pair of second spring supports are formed with a pair of second step portions on the inner side than between the step portions, and these second step portions serve as stoppers for one-way sliding, and are slidably fitted onto the spool. A manual directional control valve characterized in that an auxiliary spring is interposed between the second spring receivers, and the auxiliary spring and a return spring are arranged in parallel.