JPH0440049Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is a rotary hydraulic system that can be used to switch the supply and discharge of pressure oil to hydraulic cylinders, hydraulic actuators, hydraulic pumps, and other hydraulically operated machines. This relates to switching valves.

[Prior art]

Various hydraulic machines require a switching valve that can appropriately switch between the supply direction and the discharge direction of pressure oil. For example, in FIGS. 1 and 2, which schematically illustrate the hydraulic system in a hydraulic cylinder, as shown in FIG.
When the oil is pumped into the right chamber 5 of the cylinder, the piston 6 moves to the left and the rod 7 protrudes, and at this time, the oil in the left chamber 8 pushed out of the cylinder by the piston 6 passes through the switching valve 3 and flows into the oil tank 1. be returned. Furthermore, when the switching valve 3 is switched to the state shown in FIG.
The rod 7 is drawn into the cylinder, and the oil in the right chamber 5 is returned to the oil tank 1 via the switching valve 3.

One type of switching valve that operates in this manner is a rotary switching valve that switches the hydraulic path by rotating a cylindrical left-handed rotary shaft valve 11 within a casing 10, as shown in FIG. (Jitsukai 1986
−51366). First, to explain the structure and operation of this rotary type switching valve, a pair of left and right rotary shaft valves 11 and 12 each having a circular cross section are connected at their ends in a casing 10, and are slidably connected to each other so as to be rotatable within the same casing 10. It is mandatory. Pump 2 (Fig. 1, 2
A pressure port P leading to a pressure oil source such as the one shown in FIG. The control port B leading to the right chamber 5 of the hydraulic cylinder 4 is connected to the control passage 1 at the end of the right rotation shaft valve 12.
5a, 15c via channels 16a, 16c, and the control port A that communicates with the left chamber 8 of the cylinder 4 is connected to the control channels 15b, 15d via channels 16b, 16d.
It is connected through. The first opening 1 of the pressure port P at the end of the left rotary shaft valve 11 is located at this end.
3, 13 and the second opening 14, 1 of the tank port T
control surface portions 17a, 17b, which shield 4 when in neutral;
17c and 17d are arranged. The groove widths of the control passages 15a, 15b, 15c, and 15d are smaller than the diameters of the first opening 13 of the pressure port P and the second opening 14 of the tank port T.

The operation of the rotary type switching valve constructed in this way is as follows. First, when the left rotary shaft valve 11 is brought into the state shown in FIG.
The flow channels 16a, 16 are sent from the first openings 13, 13 to the control channels 15a, 15c of the right rotary shaft valve 12.
It communicates with the control port B through c and sends pressure oil into the right chamber 5 of the cylinder 4. At the same time, the oil in the left chamber 8 (with almost no pressure) flows through the flow path 16 that communicates with the control port A.
b, 16d, the oil enters the second openings 14, 14 of the left rotary shaft valve 11 through the control passages 15b, 15d, and is returned to the oil tank 1 through the tank port T. This causes the piston 6 to move to the left, but on the other hand, the piston 6
In the right row, when the left rotary shaft valve 11 is in the state shown in FIG. Pressure oil is sent to the left ventricle 8. At the same time, the oil in the right chamber 5 flows from the flow paths 16a, 16c communicating with the control port B to the control passages 15a, 15.
It enters the second openings 14, 14 through c and is returned to the oil tank 1 from the tank port T, and the piston 6 moves to the right. The piston 6 is stopped by connecting the first openings 13, 13 and the second openings 14, 14 to the control surface parts 17a, 17b,
This can be done by blocking the flow path of pressure oil by shielding with 17c and 17d (fifth
figure).

[Problem that the invention attempts to solve]

However, the rotary type switching valve of the prior art described above has good responsiveness to the load of hydraulic machinery,
Although the structure is simple and easy to handle, it has been found that when the rotary shaft valve is rotated and the oil pressure is changed over a long period of time, oil leaks from the end where the rotary shaft valve joins. In order to prevent this oil leak, the rotary shaft valves were strongly tightened so that they were closely connected to each other, but excessive tightening can prevent oil leakage but still requires excessive force to rotate the rotary shaft valve. It requires

The present invention was developed to eliminate these drawbacks, and provides an improved rotary hydraulic switching valve that does not cause oil leaks even after long-term use and can be used with small rotational force. The purpose is to

[Means for solving problems]

In order to achieve the above object, the present invention has a structure in which the ends of a pair of left and right rotary shaft valves are joined and slidably contact each other in a rotatable manner within the same casing, and a pressure port is provided on the sliding surface of one of the rotary shaft valves. and a tank port, and a groove-shaped control port is formed on the sliding surface of the other rotary shaft valve, and at the end, a pressure port is provided between each control port, and a control surface portion that shields the tank port when in neutral is formed. The rotary type switching valve is a rotary type switching valve arranged so that a large number of thrust balls are provided along the circumferential direction on the outer peripheral surface of either end of the left and right rotary shaft valves so that the left and right rotary shaft valves are closely joined together. , the gist is that the one rotary shaft valve is provided with a pressurizing chamber that presses the end of the one rotary shaft valve against the end of the other rotary shaft valve using pressure oil from the pressure port side. It is something.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 6 is a schematic sectional view showing the structure of a rotary hydraulic switching valve according to an embodiment of the present invention, and FIG. 7 is a perspective explanatory view of the right-hand rotary shaft valve.

In FIG. 6, the reference numerals are the same as in FIG. 3, so their description will be omitted. In the figure, 20 indicates a pressurizing chamber, and 21 indicates a thrust ball. Note that 20a is a branch road. Also,
The hydraulic system in the hydraulic cylinder including the switching valve of this embodiment and the operating state of the valve when the rotary shaft valve rotates are the same as those shown in FIGS. 1, 2, and 5 shown in the explanation of the conventional example, so I will explain based on the diagram.

Inside the casing 10, a pair of left and right rotary shaft valves 11 and 12 each having a cross-sectional shape are joined at their ends and slidably contact each other so as to be rotatable within the same casing 10. A pressure port P and a tank port T are formed, and groove-shaped control ports A and B are formed on the sliding surface of the right-hand rotary shaft valve 12.

A pressure port P leading to a pressure oil source such as a pump 2 (Figs. 1 and 2) communicates with a first opening 13 at the end of the left rotary shaft valve 11, and is connected to an oil tank 1 (Figs. 1 and 2). The tank port T leading to the second opening 14 is in communication with the second opening 14 .

The control port B that communicates with the right chamber 5 of the hydraulic cylinder 4 (see FIGS. 1 and 2) is connected to the control passages 15a and 15c at the end of the right rotation shaft valve 12, and the flow passages 16a and 1 are connected to the right chamber 5 (see FIGS. 1 and 2).
6c, and communicates with the left ventricle 8 (first
The control port A that communicates with the control passages 15b and 15d via channels 16b and 16d (see FIG. 5) is connected to the control passages 15b and 15d (see FIG. 5).

A first opening 1 of the pressure port P at the end of the left rotary shaft valve 11 is provided at the end of the right rotary shaft valve 12.
3, 13 and the second opening 14, 1 of the tank port T
4 (see left rotation shaft valve 11 in FIG. 4) when in neutral state.
d is placed.

In addition, the control passages 15a, 15b, 15c, 1
The groove width 5d is smaller than the diameter size of the first opening 13 of the pressure port P and the second opening 14 of the tank port T.

The pressurizing chamber 20 is branched from the pressure port P of the left rotary shaft valve 11 and connected to the left rotary shaft valve 1 via a branch passage 20a.
It is provided on the opposite side of the end of 1.

A large number of thrust balls 21 are arranged along the circumferential direction on the outer circumferential surface of the end of the right rotary shaft valve 12, so as to smoothly rotate the ends of the left and right rotary shaft valves 11, 12. , and the diameter size of the thrust ball 21 is set to a size that allows the rotary shaft valves 11 and 12 to be brought into close contact with each other. The thrust ball 21 may be provided on the outer circumferential surface of the end of the right rotary shaft valve 12, but may also be provided on the outer circumferential surface of the end of the left rotary shaft valve 11.

Note that the operation of the hydraulic system in the hydraulic cylinder including the switching valve of this embodiment is the same as that described in the conventional example, so a description thereof will be omitted.

[Effects of the invention] The rotary hydraulic switching valve of the present invention configured as described above always closes the end of the left rotary shaft valve when rotating and switching the left and right rotary shaft valves in order to supply and discharge pressure oil to a hydraulic machine. Since the part is pressed against the end of the right-hand rotary shaft valve by the pressure oil in the pressurized chamber branched from the pressure port, it is possible to more completely prevent oil from leaking from the end of the right-hand rotary shaft valve. can.

Further, since the thrust balls are arranged along the circumferential direction on the outer circumferential surface of the end portion of the right-hand rotary shaft valve, it can be used with a small rotational force, and has the effect of making the rotation smoother.

Thus, the rotary hydraulic switching valve of the present invention is
Even after long-term use, due to the effect of the pressurized chamber, there is almost no oil leakage from the joining ends of the left and right rotary shaft valves, and the effect of the thrust ball allows for smooth rotation even with small rotational force. Since it is possible to switch the load, it has excellent responsiveness to the load of the hydraulic machine and has extremely practical value.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams schematically showing an example of a hydraulic system provided with a switching valve. FIG. 3 is a schematic sectional view showing an embodiment of the conventional switching valve. 4 is a perspective explanatory view of the left and right rotary shaft valve of the switching valve of FIG. 3; FIG. FIG. 5 is a sectional view showing the operating state of the valve when the rotary shaft valve is rotated. FIG. 6 is a schematic sectional view showing an embodiment of the rotary hydraulic switching valve of the present invention, and FIG. 7 is a perspective explanatory view of the right-hand rotary shaft valve. 1... Oil tank, 2... Pump, 3... Switching valve, 4... Cylinder, 5... Right chamber, 6... Piston, 7... Rod, 8... Right chamber, 10... Casing, 11 ... Left rotation shaft valve, 12 ... Right rotation shaft valve, 13 ... First opening, 14 ... Second opening, 15
a, 15b, 15c, 15d...control passage, 1
6a, 16b, 16c, 16d...channel, 17
a, 17b, 17c, 17d... control surface section, 20
... Pressure chamber, 21 ... Thrust ball, T ... Tank port, P ... Pressure port, A, B ... Control port.

Claims (1)

[Scope of utility model registration request] The ends of a pair of left and right rotary shaft valves are joined and slidably contact each other in the same casing so that they can rotate freely, and a pressure port and a tank port are formed on the sliding surface of one rotary shaft valve. It is a rotary type switching valve that has a groove-shaped control port formed on the sliding surface of the valve, and a control surface section that shields the pressure port and tank port at the end between each control port when in neutral mode. A large number of thrust balls are provided along the circumferential direction on the outer circumferential surface of either end of the shaft valve so that the left and right rotary shaft valves are closely joined together, and a A rotary hydraulic switching valve characterized in that a pressurizing chamber is provided for pressing an end of the one rotary shaft valve against an end of the other rotary shaft valve using pressure oil.