JPS6146711B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flow dividing valve suitable for controlling the operation of a steering gear and other devices.

Conventionally, the control system of a steering gear operated with fluid from a hydraulic pump driven by a marine propulsion engine includes a fluid inflow path a through which control fluid flows into a diverter valve, that is, a valve housing, as shown in Figure 1. , an outflow path c connected to this through an orifice b is provided, and an inflow path a on the upstream side of the orifice b is connected to a discharge path d.
A branch road e is provided to branch and connect to the branch road e, and the branch road e is
The inlet passage a is actuated to the opening side by the force due to the pressure difference before and after the orifice b, and to the closing side by the force by the spring f.
It is common practice to use a flow divider valve equipped with a flow control spool g that discharges a part of the control fluid flowing into the flow path to the discharge path.According to this, as the engine speed increases, the flow from the hydraulic pump to the flow path a When the inflowing flow rate increases and the differential pressure across the orifice b becomes greater than the elastic force of the spring f, the spool g moves to the branch path e.
is opened to discharge the excess flow rate from the discharge path d to the tank, and the controlled flow rate of the outflow path c is controlled to be substantially constant as shown in the second diagram.

Therefore, when the ship's speed is high and the rudder is well controlled, the steering gear operates relatively slowly, and when the ship's speed is slow and the rudder is poorly controlled, it is easier and safer to operate the steering gear if it operates quickly. Preferably, the flow dividing valve used in the control system of the steering gear operates to gradually reduce the flow rate to the steering gear as the engine speed increases and the flow rate from the hydraulic pump increases beyond a certain value. Such valves that gradually reduce the flow rate are also disclosed in, for example, Japanese Patent Application Laid-open No. 18823-1982, Japanese Patent Publication No. 28992-1972, and Japanese Patent Application Laid-open No. 70429-1982.
It is not possible to gradually reduce the control flow rate over a wide range without being affected by changes in load pressure.

An object of the present invention is to provide a flow dividing valve suitable for controlling the flow rate to gradually decrease over a wide range without being affected by fluctuations in load pressure. , an outflow path connected to the fluid inflow path via an orifice is provided, and a branch path is provided that connects the inflow path upstream of the orifice to a discharge path, and the branch path has a differential pressure before and after the orifice. In a device equipped with a diversion control spool that is actuated to the opening side by the force of the spring and to the closing side by the force of the spring to control the discharge of the control fluid flowing into the inflow passage into the discharge passage, the front part of the diversion control spool is A second orifice is provided in the branch path, and the second
Connecting a branch path in front of the control spool and an outflow path behind the orifice via a third orifice;
The third orifice is formed to have a smaller area than the other orifices.

An embodiment of the present invention will be described with reference to FIG. 3. Reference numeral 1 denotes a valve housing of a diverting valve, 2 a fluid inflow path formed in the valve housing 1 into which the control fluid flows, and 3 a fluid inflow path 2.
An outflow path is connected to the orifice 4 through an orifice 4 and sends fluid to an actuator such as a steering gear, 5 is a branch path formed to branch and connect the inflow path 2 to the discharge path 6 from the upstream side of the orifice 4, and 7 is a branch path. A diversion control spool is shown that opens and closes between the branch passage 5 and the discharge passage 6, and both ends of the spool 7 are formed to have the same area so as to face the chambers 8 and 9. Then, the pressure in front of the orifice 4 is introduced into one chamber 8 via the pilot circuit 10, and the pressure behind the orifice 4 is introduced into the other chamber 9 via the pilot circuit 11. The spool 7
The spool 7 is actuated to the opening side to communicate the branch passage 5 with the discharge passage 6 by the force of the differential pressure before and after the orifice 4;
The force of the spring 12 can be used to close the communication, thereby controlling the discharge of the control fluid flowing in from the inflow path 2 from the discharge path 6, and allowing the remaining flow rate to flow into the outflow path 3. . The above configuration is almost the same as the conventional one, but in the one of the present invention, there is a second orifice 1 in the branch passage 5 in front of the branch flow control spool 7.
3 to create a pressure drop in the fluid flowing from the inlet passage 2 through the branch passage 5 and the control spool 7 to the discharge passage 6, and behind the second orifice 13 and in front of the control spool 7. The branch path 5 and the outflow path 3 are determined by the area of the orifice 4 and the second
It is connected through a third orifice 15 having an area smaller than that of the orifice 13, and when the pressure in the outlet passage 3 increases, a part of the fluid in the outlet passage 3 flows through the third orifice 15 to the discharge passage 6. This allows the flow rate of the outflow path 3 to be reduced. 16 is a safety valve.

To explain the operation of the embodiment shown in the third diagram, a flow rate proportional to the engine speed flows in from the inlet passage 2, and when the flow rate does not reach the set flow rate, that is, the flow rate at which the diversion control operation is started, there is no intervention. The pressure drop caused by the orifice 4 is also small,
Since the difference between the pressure in front of the orifice 4 and the pressure behind the orifice 4 acting on both ends of the diversion control spool 7 is small, the diversion spool 7 resists the spring 12 and
does not move to the extent that it communicates with the discharge passage 6, and therefore the entire flow flowing into the inlet passage 2 flows out from the outlet passage 3 to operate the steering gear or the like. When the rotational speed of the engine increases and the flow rate exceeds the set flow rate, the diverter spool 7 moves to the left in the drawing until it balances the elasticity of the spring 12 and connects the branch path 5 to the discharge path 6.
Although the flow rate passing through the orifice 4 is controlled to be constant, a portion of the flow rate flowing into the inlet passage 2 is discharged from the discharge passage 6 in the following manner. That is, when the flow rate flowing into the inflow path 2 is slightly higher than the set flow rate, some flow rate is diverted to the branch path 5, but in this case, the pressure drop caused by the second orifice 13 of the branch path 5 is reduced by Since the pressure drop is smaller than the pressure drop, the pressure in the branch passage 5 behind the second orifice 13 is higher than the pressure behind the orifice 4;
Therefore, a part of the branched flow rate of the branch passage 5 flows through the third orifice 15 to the outflow passage 3, and the flow rate of the outflow passage 3 becomes the sum of the flow rate passing through the orifice 4 and the flow rate passing through the orifice 15. The remainder of the branched flow rate of the branch path 5 is discharged from the discharge path 6. When the flow rate in the inflow passage 2 increases further than in the above case, the flow rate through the orifice 4 is constant, so the flow rate in the branch passage 5 flowing through the second orifice 13 increases more than in the above case. In this case, the pressure drop through the second orifice 13 becomes large, and the pressure in the branch passage 5 behind it and the pressure behind the orifice 4 become less different, and as a result, the flow rate flowing into the outlet passage 3 via the third orifice 15 becomes zero. So, branch road 5
All of the flow rate is discharged from the discharge path 6, and the controlled flow rate flowing out from the outflow path 3 gradually decreases as shown in part A of the characteristic curve in FIG. Then, when the flow rate from the inflow passage 2 increases, the pressure drop in the second orifice 13 becomes larger than the pressure drop in the orifice 4, and the pressure behind the second orifice 13 in the branch passage 5 becomes lower than the pressure in the outflow passage 3. As the flow rate becomes lower, a backflow occurs in the third orifice 15 from the outflow path 3 to the branch path 5, and a part of the controlled flow rate from the outflow path 3 is discharged to the discharge path 6, resulting in the curve part B in FIG. As shown, the controlled flow rate from the outflow path 3 is further reduced. Curve E in FIG. 4 is the flow rate flowing from the inflow path 2 to the outflow path 3 through the orifice 4, and curve F is the flow rate flowing from the branch path 5 to the outflow path 3 through the third orifice 15. The direction of the flow is reversed in the section and flows from the outflow path 3 to the branch path 5.

When the inflow flow rate increases extremely, most of the flow rate from the inflow path 2 will be discharged to the exhaust path 6, but if the control flow rate disappears, the control system will become inactive, so the maximum engine rotation speed will decrease. An appropriate usage range c is determined so that a controlled flow rate can be obtained at the maximum flow rate.

The flow rate from the outflow path 3 is controlled by the control spool 7, which operates to compensate for the pressure difference in the orifice 4 even if the load pressure fluctuates due to the steering device connected to it. The flow rate of the outflow path 3 is not changed due to fluctuations in the flow rate.
In the embodiment shown in FIG. 5, in addition to a land portion 17 that controls the opening and closing of the branching path 5 and the discharge path 6, a pair of land portions 18a that prevent fluid from flowing into the outflow path 3 are provided on the spool 7. 18b and an orifice 4 is provided in one of the land portions 18a, and an axial through hole 19 is formed in the spool 7 and the through hole 19 is formed in the land portion 1.
A radial opening 20 is formed to communicate between the inflow passage 2 and the through hole 1 to constitute the branch passage 5.
9. A small hole is formed through the through hole 19 to communicate with the outflow path 3, and the second orifice 13 and the third orifice 1 are connected to each other.
5, and if its overall configuration is represented by symbols, it will be as shown in Fig. 6, and it will have substantially the same effect as the embodiment shown in Fig. 3. In place of the second orifice 13, a device that increases the pressure drop as the flow rate increases, such as a relief valve or check valve with an override, may be provided.

In this way, according to the present invention, in addition to the orifice provided between the inflow path and the outflow path, a second orifice between the inflow path and the branch path and a third orifice between the branch path and the outflow path are provided.
By providing an orifice and making the third orifice smaller than the other orifices, it is possible to gradually reduce the control flow rate over a wide range after the start of diversion, and when the inflow flow rate increases, the control flow rate suddenly drops to zero, resulting in, for example, unsteering. It is convenient because the controlled flow rate is not affected by fluctuations in load pressure and can accurately control the deceleration of the steering gear and other equipment, and its configuration is relatively simple and inexpensive to manufacture. It has the effect of being able to do something.

[Brief explanation of the drawing]

FIG. 1 is a cut-away side view of a conventional diverting valve, FIG. 2 is a control characteristic curve diagram of the conventional diverting valve, FIG. 3 is a cut-away side view of the first embodiment of the present invention, and FIG. 4 is a cut-away side view of the conventional diverting valve. FIG. 5 is a cutaway side view of a second embodiment of the present invention, and FIG. 6 is a diagram showing a symbol of the diverter valve of the present invention. 2...Inflow path, 3...Outflow path, 4...Orifice, 5
...Diversion path, 6...Discharge path, 7...Diversion control spool,
12...Spring, 13...Second orifice, 15...Third
Orifice.

Claims (1)

[Claims] 1 a fluid inflow path through which control fluid flows into the valve housing;
An outflow path connected to the fluid inflow path via an orifice is provided, and a branch path is provided that connects the inflow path upstream of the orifice to a discharge path, and the branch path is provided with an outflow path connected to the fluid inflow path via an orifice. A branch at the front of the shunt control spool in a device equipped with a shunt control spool that is actuated to open by force and to close by force by a spring to control the discharge of the control fluid flowing into the inflow passage into the discharge passage. A second orifice is provided in the passage, and behind the second orifice, the branch passage in front of the control spool and the outflow passage are connected via a third orifice, and the area of the third orifice is made larger than that of the other orifices. A flow rate gradually decreasing type diverter valve characterized by being formed in a small area.