JPH044306A - Hydraulic direction control valve - Google Patents

Abstract

PURPOSE:To reduce an attachment width by arranging a fixed number of unit changeover valves of stack type center bypass structure in two rows back to back each other, communicating a center bypass passage, high pressure oil passage and a tank passage together for each row, and forming pump port on one side of each row and exhaust oil passage communicating to tank passage and a tank port on the other side. CONSTITUTION:For instance, 8 unit changeover valves 2a1-a4, 2b1-b4, are arranged back to back to form changeover valve rows A, B, and inlet covers 3,4 are arranged on one side of the rows A, B, and manifolds 5 are arranged in both rows on the other side. The unit changeover valves 2 are made in such that high pressure oil passages 12a, b, center bypass passages 17a, b and tank passages 18a, b are communicated together, and pump ports 21a, b communicated to the passages 17a, b are provided in the inlet covers 3,4. A high pressure oil communicating passage 25 for communicating the passages 12a, b together, an exhaust oil passage 26 for connecting the passages 17a, b, 18a, b with each other, and a tank port 27 communicating thereto are equipped to the manifold 5. It is possible by this constitution to reduce an attachment width.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydraulic directional control valve used in a hydraulic control mechanism of, for example, a small civil engineering machine.

[Conventional technology]

The hydraulic directional control valves used in the above-mentioned civil engineering machines, such as hydraulic excavators, are usually stack type, and as shown in FIG. 6, each unit switching valve 51, 51... is arranged in one row, and inlet covers 52... 53 is attached to form the hydraulic directional control valve 50. Each unit switching valve 51 has a center bypass structure, and as shown in the hydraulic circuit diagram in FIG. pump port P x.

py and tank ports Tx and Ty are provided.

[Problem to be solved by the invention]

As shown in FIG. 8, the hydraulic directional control valve installed in the hydraulic excavator, particularly the micro-excavator M, is sandwiched between the knees of the worker W, and the seat 5
It is installed at the front of 7.

However, the hydraulic directional control valve 50 requires a large number of unit switching valves (usually 8 valves) for ultra-small excavators as well as for large excavators, and due to the discharge amount of the hydraulic pump and the dimensions of the hydraulic cylinder, The hydraulic directional control valve cannot be made small due to its function and structure, and therefore the horizontal medium dimension L of the hydraulic directional control valve 50 is
S is quite large in size, and there is a limit to the distance between the legs and knees in the operator's posture during operation due to the human body shape, which poses problems such as interfering with work.

In view of these points, the present invention has been developed in the case of an ultra-compact hydraulic excavator that aims to have a dead weight of 350 kgf and can be carried on a light truck, in particular, where space is extremely limited and the hydraulic directional control valve has a different arrangement and dimensions than conventional ones. The purpose of this project is to provide a directional control valve with a narrower mounting width and the same capacity as the conventional one.

[Means to solve the problem]

A first invention to achieve the above object is to divide a predetermined number of unit switching valves of a stack type center bypass structure into two halves and arrange them back to back to form two rows of switching valve rows, and each row In addition to communicating the center bypass passage, high pressure oil passage, and tank passage for each row, there is a pump port on one side of each row, and a manifold installed on the other side of each row has an oil drain port that connects the tank passages of both rows. A passage and a tank port communicating with this oil drainage passage are formed.

Further, in the second invention, a predetermined number of unit switching valves of a stack type center bypass structure are divided into two and arranged back to back to form two rows of switching valve rows, and each row has a center bypass passage, In addition to communicating high pressure oil passages and tank passages,
A pump port is provided on one side of one row, a tank port is provided on one side of the other row, and the manifold installed on the other side of each row has a center bypass passage, a high pressure oil passage, and a tank passage for both rows. A communication passageway is formed to communicate with each other.

In the first and second aspects of the invention, at least one of the two cylinder ports provided in each unit switching valve is
Preferably, the cylinder ports are provided in a direction parallel to the spool valve.

[For production]

In both the first and second inventions, a large number of unit switching valves are divided into 9゛2 parts and arranged back to back, so the length of the hydraulic directional control valve is about half of the conventional length. The width of the mounting location can be shortened, making operation easier.

〔Example〕

1 to 4 show a first embodiment. The hydraulic directional control valve 1 has a predetermined number, for example, eight unit switching valves 2al to 2a4,
2bl ~ 2b4 (hereinafter referred to collectively as simply 2)
It is desired that two rows of switching valves A be arranged back to back, that is, symmetrically, in the center.

Inlet covers 3 and 4 are provided on one side of each row A and H, and a manifold 5 common to both rows is provided on the other side and fastened by tie rods 6.

Each unit switching valve 2 is a center bypass type 3-position, 4-way manual switching spool valve, and a cross-sectional view of the same is shown in FIG. The figure shows a cross-sectional view along line I-I in Figure 2.
Hereinafter, one unit switching valve 2al will be explained, and the explanation of the other unit switching valve 2bl will be omitted by replacing the suffix a with b for the same parts.

The manual spool valve 10a of the unit switching valve 2al is provided with a return spring lla for holding it in a neutral position, and the high pressure oil passage 12a is connected to the left and right supply boats 14a via a load check valve 13a. 15a and 16a are cylinder ports, 17a is a center bypass passage, and 18
a is a tank passage.

An elbow 19a is attached to one cylinder port 16a as a piping joint, and the other cylinder port 15a is bent downward to be parallel to the spool 10a to form an outlet below, to which a straight pipe joint 20a is attached.

The unit switching valves 2 are connected as shown in FIGS. 1 and 2 to communicate with the high pressure oil passages 12a and 12b, the center bypass passages 17a and 17b, and the tank passages 18a and 18b, respectively. , 4 are provided with pump ports 21a, 21b connected to the center bypass passages 17a, 17b, respectively. 22a, 22
b is a center bypass passage 17a, respectively.

It is a main relief valve provided between 17b and tank passages 18a and 18b.

The manifold 5 also includes high pressure oil passages 1 in rows A and B.
High-pressure oil communication passage 25 that communicates 2a and 12b, and center bypass passage 17a, 17b + tank passage 18
an oil drain passage 26 connecting a and 18b and this oil drain passage 2
6 is provided.

With the above configuration, the hydraulic directional control valve 1 has a required number of unit switching valves 2 divided into approximately two halves and arranged back to back, so that the installation width can be shortened.

FIG. 4 shows an example in which the hydraulic directional control valve 1 of the present invention is applied to an ultra-small hydraulic excavator M. That is, the width IS of the hydraulic directional control valve 1 is much shorter than the conventional length LS, so that the operator W does not get in the way when installing the hydraulic directional control valve 1, and the operation is convenient.

Note that this embodiment uses unit switching valves 2a1 to 2a4.2b1 to 2.
b4 is constructed individually and arranged back to back, but this is a monoblock structure in which two unit switching valves are formed back to back in one valve body, for example, unit switching valves 2al and 2bl. and as a single structure,
You can also set these up in sequence. Further, the inlet covers 3 and 4 may also be integrally formed on the left and right sides as described above.

Next, FIG. 5 shows a second embodiment. In the first embodiment described above, pump ports 21a and 21b were formed for each of the A row and B row, and pressure oil was supplied from two pumps, but in this embodiment, all the pressure oil is supplied by one pump. An example of supplying pressure oil to a unit switching valve is shown.

That is, the hydraulic directional control valve 30 of this embodiment has the required number of unit switching valves 2a1 to 2a4, 2bl to 8, for example, as in the previous example.
2b4 is divided into two rows A and B, and the inlet cover 31 is placed on one side of the negative row, for example, row A, and the outlet cover 32 is placed on one side of the other row B, and the other side of both rows is A common manifold 33 is arranged. In each row A and B, high pressure oil passages 12a and 12bl communicate with center bypass passages 17a and 17b and tank passages 18a and 18b, respectively, as in the previous example. The inlet cover 31 is provided with a pump port 34 connected to the center bypass passage 17a. 35
is a main relief valve, which is attached to the inlet cover 31 and is connected to the center bypass passage 17a and the tank passage 1.
8a. The outlet cover 32 has a tank port 36 connected to the center bypass passage 17b.
Equipped with In addition, the manifold 33 includes a high pressure oil passage 12a,
12b, high pressure oil communication passage 37, center bypass passages 17a, 17b, and tank passages 18a, 18b.
A center bypass communication passage 38 and a tank communication passage 39 are provided, which communicate with each other.

Note that each unit switching valve 2 has the same structure as the previous example, and a description thereof will be omitted.

In this embodiment, one pump selectively operates each unit switching valve 2, and as in the previous example, the required number of unit switching valves 2 are divided into approximately two halves and arranged back to back. This allows the installation width to be shortened.

In the case of this embodiment as well, as described above, two unit switching valves may be arranged back to back in one valve body, and these may be combined.

(Effects of the Invention) In both the first and second inventions, a predetermined number of unit switching valves are arranged back to back in the center to form two rows of switching valves. The method is the same as that of a switching valve, and the installation width is much shorter than that of the conventional structure, making installation and operation convenient even in narrow spaces.

Furthermore, by providing at least one of the paired cylinder ports of each unit switching valve in parallel with the spool valve, the protrusion of the pipe fitting attached to the cylinder port can be reduced, and the overall dimensions can be reduced. can.

[Brief explanation of drawings]

1 to 4 relate to the first embodiment, in which FIG. 1 is a hydraulic circuit diagram of a hydraulic directional control valve, FIG. 2 is a perspective view thereof, and FIG. 3 is a cross section taken along line I-I in FIG. 2. Fig. 4 is an explanatory view showing the state in which the hydraulic directional control valve of the present invention is installed on a micro-excavator, Fig. 5 is a hydraulic circuit diagram of the hydraulic directional control valve of the second embodiment, and Fig. 6 Figures 8 to 8 relate to conventional examples, Figure 6 is a plan view of a conventional hydraulic directional control valve, Figure 7 is its hydraulic circuit diagram, and Figure 8 is the hydraulic directional control valve installed in an ultra-small hydraulic excavator. It is a usage explanatory diagram showing the state. 1.30 is a hydraulic directional control valve, 2al~, 2b1~ are unit switching valves, 5.33 is a manifold, 12a, 12b are high pressure oil passages, 15a, 15b, 16a, 16b
are cylinder ports, 17a, 17b are center bypass passages, 18a, 18b are tank passages, 21a,
2lb, 34 is a pump port, 26 is an oil drain passage, 27.36 is a tank port, 37 is a high pressure oil communication passage, 38 is a center bypass communication passage, and 39 is a tank communication passage.

Claims (4)

[Claims] (1) A predetermined number of unit switching valves with a stacked center bypass structure are arranged back to back in the center to form two rows of switching valves, and each row has a center bypass passage, a high pressure oil passage, and a tank. In addition to communicating the passages, a pump port is installed on one side of each row, and the manifold installed on the other side of each row has an oil drain passage that connects the tank passages of both rows and a tank port that leads to this oil drain passage. A hydraulic directional control valve characterized by: (2) A predetermined number of unit switching valves with a stacked center bypass structure are divided into approximately two halves and arranged back to back to form two rows of switching valves, and each row has a center bypass passage, a high pressure oil passage, and a tank. In addition to communicating the passages, a pump port is provided on one side of one row, and a tank port is provided on one side of the other row.The manifold installed on the other side of each row has a center bypass passage for both rows, a high-pressure oil A hydraulic directional control valve characterized in that a communication passage is formed that connects a passage and a tank passage. (3) The hydraulic directional control valve according to claim 1 or 2, wherein at least one cylinder port among the two cylinder ports provided in each unit switching valve is provided in a direction parallel to the spool valve. (4) Claim 1 consisting of a monoblock having a stack type center bypass structure, in which a center bypass passage, a high pressure oil passage, and a tank passage are formed back to back at approximately the center of the block.
Hydraulic directional control valve described in .