JP3971879B2 - Multiple valves - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multiple valve optimum for use in a construction vehicle or the like.
[0002]
[Prior art]
As this type of multiple valves, those described in Japanese Patent Application Laid-Open No. 11-257302 are conventionally known. FIG. 3 shows a circuit of this conventional multiple valve.
As is apparent from FIG. 3, this multiple valve has a subsection block 3 interposed between the main section block 1 and the cover 2.
The main section block 1 incorporates a plurality of main switching valves 4 and a center bypass passage 5 of the main switching valves 4 is connected in series.
[0003]
Further, the sub section block 3 incorporates a sub switching valve 6, and a center bypass passage 7 of the sub switching valve 6 is directly communicated with an extension of the center bypass passage 5 of the main switching valve 4.
The center bypass passage 7 of the sub switching valve 6 includes a first return passage 8 formed in the cover 2 → a second return passage 9 formed in the subsection block 3 → a third return passage 10 formed in the main section valve 1. It communicates with the tank T via.
[0004]
The third return passage 10 is provided with a pilot pressure generating means 11 for generating a pilot pressure for reducing the discharge amount of the pump P. Accordingly, if all of the switching valves 4 and 6 are in the neutral position, the discharge oil of the pump P is returned to the tank T via the first to third return passages 8 to 10. Since the discharged oil passes through the pilot pressure generating means 11, the pilot pressure is generated there.
The regulator 12 operates by the action of the pilot pressure, and the discharge amount of the pump P is reduced. That is, the discharge amount of the pump P is kept to the minimum in the situation where each switching valve is kept at the neutral position and the actuator is not working.
[0005]
In addition to the actuators normally required in construction vehicles, special actuators may be optionally connected. In such a case, the subsection block 3 is required so that an optional actuator can be easily connected. That is, the reason why the subsection block 3 is provided as described above is to connect an optional actuator to the last.
[0006]
[Problems to be solved by the invention]
In the conventional multiple valve as described above, the center bypass passage 7 of the sub switching valve 6 is directly communicated with the extension of the center bypass passage 5 of the main switching valve 4, so that the center bypass passages 5 and 7 and Will pass through the middle of the main section block 1. Therefore, the effective space is inevitably reduced around the passage 13 of the main section block 1.
[0007]
Since the effective space is small as described above, it becomes impossible to incorporate other devices in this portion. Therefore, the pilot pressure generating means 11 must also be provided on the third return passage 10 side as shown in FIG.
When the pilot pressure generating means 11 is provided on the third return passage 10 side in this way, the width of the main section block 1 must be increased accordingly. In other words, according to this conventional multiple valve, there is a problem that the whole is increased in size.
[0008]
Further, in this conventional multiple valve, there is a path for returning the return oil when the switching valves 4 and 6 are neutral to the tank via the first return passage 8 → the second return passage 9 → the third return passage 10. The pilot pressure generating means 11 is provided in the third downstream return passage 10 at the most downstream side. Therefore, the distance from the sub switching valve 6 of the subsection block 3 to the pilot pressure generating means 11 becomes long. Thus, if the distance to the pilot pressure generating means 11 becomes long, the pressure loss increases accordingly. As the pressure loss increases, the pilot pressure generated by the pilot pressure generating means 11 is more susceptible to changes in the oil temperature. For this reason, there is a problem that the control of the pump discharge amount becomes unstable.
[0009]
A first object of the present invention is to enable a large effective space on the downstream side of the main section block.
The second object is to allow various control devices to be incorporated in the effective space.
A third object is to incorporate a pilot pressure generating means for controlling the pump discharge amount into the effective space so that a stable pilot pressure can be detected.
A fourth object is to incorporate a neutral cut valve upstream of the pilot pressure generating means so that the discharge oil of the pump connected to this multiple valve can be merged with another circuit system. .
[0010]
[Means for Solving the Problems]
The present invention is based on the following multiple valve. That is, the sub section block is interposed between the main section block and the cover. The main section block incorporates a plurality of main switching valves formed by connecting center bypass passages in series. One or a plurality of sub switching valves are incorporated in the sub section block, and the center bypass passage of the sub switching valve is connected to the center bypass passage of the main switching valve via the communication path. In addition, the center bypass passage of the sub switching valve is returned to the tank via a return passage formed in the main section block.
[0011]
Based on the above multi-valve, the first invention forms a first communication passage downstream of the center bypass passage of the main switching valve located at the most downstream, and the first communication passage is formed in a subsection block. The second communication passage and the third communication passage formed in the cover are connected to the center bypass passage of the sub switching valve, and the center bypass passage of the sub switching valve is connected to the first return passage formed in the main section block and The tank is communicated with the tank via the second return passage, and the first communication passage is characterized by being offset with respect to the center bypass passage of the main switching valve and the sub switching valve.
[0012]
According to a second aspect of the present invention, an opening of the first return passage is formed on the extension of the center bypass passage of the sub switching valve, and the second return passage is connected to the tank via the side of each switching valve of the main section block. It has the feature in the point led to.
The third invention is characterized in that pilot pressure generating means for controlling the pump discharge amount is provided in the first return passage.
4th invention is the 1st return path, Comprising: It has the characteristics in the point which provided the neutral cut valve in the upstream of the pilot pressure generation means.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
In the first embodiment shown in FIG. 1, two subsection blocks 23 are interposed between the main section block 21 and the cover 22. The main section block 21 incorporates a plurality of main switching valves 24, and a center bypass passage 25 of the main switching valves 24 is connected in series.
In this embodiment, two subsection blocks 23 are provided. This subsection block may be provided with one sub-switching valve in one subsection block as shown, or a plurality of sub-switching valves may be incorporated in one subsection block.
The point that the sub switching valve 26 is incorporated in the sub section block 23 is the same as in the prior art. However, in this embodiment, the flow direction of the center bypass passage 27 is different from the conventional one. This point will be described in detail later.
[0014]
The main switching valve 24 incorporated in the main section block 21 and the center bypass passage 25 of the main switching valve located on the most downstream side thereof is connected to the first communication passage 28.
The first communication path 28 is formed in the main section block 21, and the first communication path 28 is offset with respect to the center bypass path 25. That is, in the drawing, the first communication passage 28 is formed closer to the right side than the center bypass passage 25. Since the first communication path 28 is formed close to the right side of the main section block 21 as described above, an effective space S is secured on the downstream side of the main section block 21.
[0015]
The first communication path 28 is once communicated with a third communication path 30 formed in the cover 22 via a second communication path 29 formed in the subsection block 23. The third communication passage 30 is connected to the center bypass passage 27 of the sub switching valve 26 so as to return to the subsection block 23 side again from the third communication passage 30 formed in the cover 22.
[0016]
The center bypass passage 27 of the sub switching valve 26 located on the most downstream side of the sub section block 23 communicates with the tank T via the first return passage 31 and the second return passage 32 formed in the main section block 21. .
The opening 31 a of the first return passage 31 is formed on the extension of the center bypass passage 27 of the sub switching valve 26. Then, after extending slightly downstream from the opening 31a, it bends at a right angle in the left direction of the drawing and communicates with the second return passage 32 via the side of the main switching valve 24.
[0017]
The first return passage 31 as described above is provided with a pilot pressure generating means 33 for controlling the pump discharge amount. The reason why the pilot pressure generating means 33 is provided in the first return passage 31 in this way is as follows. That is, the pilot pressure generating means 33 is provided at a position closest to the most downstream sub switching valve 26, and the pressure loss therebetween is minimized.
If the pressure loss in the process in which the pressure oil reaches the pilot pressure generating means 33 is minimized, the pilot pressure is less affected by changes in the oil temperature.
[0018]
On the other hand, the pilot pressure generating means 33 could be provided in the first return passage 31 because the effective space S was secured by offsetting the first communication passage 28.
In FIG. 1, a regulator for controlling the discharge amount of the pump P is not shown, but it is exactly the same as the conventional case shown in FIG. Therefore, if the pilot pressure of the pilot pressure generating means increases, the pump discharge amount decreases, and if the pilot pressure decreases, the pump discharge amount increases.
[0019]
According to the first embodiment as described above, since the effective space S can be secured in the main section block 21, the pilot pressure generating means 33 for controlling the pump discharge amount can be provided there. Since this effective space S is at the downstream side of the main section block 21, that is, at the closest position to the sub switching valve 26 located at the most downstream side, the pressure loss up to the pilot pressure generating means 33 can be minimized. . Therefore, a stable pilot pressure can be generated without being affected by the oil temperature or the like.
[0020]
The second embodiment shown in FIG. 3 is different from the first embodiment in that a neutral cut valve 34 is provided on the upstream side of the pilot pressure generating means 33 in the first return passage 31. The other configuration is the same as that of the first embodiment.
The neutral cut valve 34 is switched between an open position for maintaining the communication state of the first return passage 31 and a closed position for blocking the communication.
[0021]
When the neutral cut valve 34 is in the open position shown in the drawing, the pilot pressure generating means 33 generates a pilot pressure for controlling the pump discharge amount, as in the first embodiment.
The neutral cut valve 34 is switched to the closed position in the following case. That is, it is a case where the discharge oil of the pump P connected to this multiple valve is merged with an actuator connected to another circuit system.
[0022]
For example, in the first embodiment, if all the switching valves 24 and 26 are kept neutral, the discharge oil of the pump P is returned to the tank T via the pilot pressure generating means 33. The pressure of the pressure generating means 33 keeps the oil discharged from the pump P to a minimum. In other words, if all the switching valves are kept neutral, the discharge amount of the pump P does not rise any time. If the discharge amount of the pump P does not increase, the combined oil for the other circuit systems cannot be supplied.
[0023]
Therefore, in the second embodiment, a neutral cut valve 34 is provided so as to block communication of the first return passage 31 as necessary. If the first return passage 31 is shut off, the pilot pressure for reducing the pump discharge amount is not generated, so that the discharge amount of the pump P increases. This increased discharge amount is supplied to another circuit system.
Also in the second embodiment, as in the first embodiment, as a result of securing the effective space S, the neutral cut valve 34 can be provided.
[0024]
【The invention's effect】
According to the first invention, the first communication passage formed in the main section block is offset with respect to the center bypass passage of the main switching valve and the sub switching valve, so that an effective space is secured on the downstream side of the main section block. it can. Therefore, various devices according to the purpose can be incorporated into this effective space, and accordingly, various applications can be handled.
[0025]
According to the second invention, it is not necessary to increase the width of the main section block even if various devices are incorporated in the effective space. In other words, even if various devices are incorporated, the whole can be kept small.
According to the third aspect of the present invention, the pilot pressure generating means for controlling the pump discharge amount is provided in the multiple return passage, so that the pressure loss up to the pilot pressure generating means can be minimized. Therefore, a stable pilot pressure can be generated without being affected by the oil temperature or the like.
According to the fourth aspect, if the first return passage is shut off using the neutral cut valve, the pressure oil can be merged into another circuit system.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing a first embodiment;
FIG. 2 is a circuit diagram showing a second embodiment.
FIG. 3 is a circuit diagram of a conventional multiple valve.
[Explanation of symbols]
21 Main section block 22 Cover 23 Sub section block 24 Main switching valve 25 Center bypass passage 26 Sub switching valve 27 Center bypass passage 28 First communication passage 29 Second communication passage 30 Third communication passage 31 First return passage 31a Opening 32 Second return passage 33 Pilot pressure generating means 34 Neutral cut valve

Claims (4)

One or more subsection blocks are interposed between the main section block and the cover, a plurality of main switching valves are incorporated in the main section block, and one or more subswitching valves are incorporated in the subsection block. At the same time, the center bypass passage of the sub switching valve is connected to the center bypass passage of the main switching valve via the communication passage, and the center bypass passage of the sub switching valve is routed through a return passage formed in the main section block. In the multiple valve structured to return to the tank, a first communication path is formed on the downstream side of the center bypass path of the main switching valve located on the most downstream side, and the first communication path is formed in the subsection block. Center bypass passage of the sub-switching valve through the second communication passage and the third communication passage formed in the cover The center bypass passage of the sub switching valve is connected to the tank via a first return passage and a second return passage formed in the main section block, and the first communication passage is connected to the main switching valve. And a multiple valve characterized by being offset with respect to the center bypass passage of the sub-switching valve. An opening of the first return passage is formed on the extension of the center bypass passage of the sub switching valve, and the second return passage is led to the tank via the side of each switching valve of the main section block. The multiple valve according to 1. The multiple valve according to claim 1 or 2, wherein a pilot pressure generating means for controlling a pump discharge amount is provided in the first return passage. 4. The multiple valve according to claim 3, wherein a neutral cut valve is provided on the upstream side of the pilot pressure generating means in the first return passage.

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