Patent Application
20050257840
1. Field of the Invention
The present invention relates to flow control valve assembly, and more particularly to a servo hydraulic flow control valve assembly.
2. Description of Related Art
A conventional hydraulic flow control valve in accordance with the prior art usually uses the rated relief valve to control the pressure. However, the conventional hydraulic flow control valve has some disadvantages that need to be solved.
1. It is inconvenient. The rated relief valve is operated when the pressure of the system is greater than the rated pressure. Consequently, the conventional does not have the function of fine turning and is unsuitable for some precise machine.
2. The conventional hydraulic flow control valve has a low safety. The pressure of the conventional hydraulic flow control valve id rated. Consequently, the high pressure may damage the system and cause a leak of the fluid when the rated pressure is high.
An automatic grinding machine, with a changeable hydraulic pressure, has a work pressure that is changed relative to the processes of grinding work piece. However, the machine with a changeable hydraulic pressure cannot release pressure in time when the system pressure over the rated pressure because the conventional control valve only controls the pressure in the inlet. Consequently, the buffer margin of the machine is reduced.
The present invention has arisen to mitigate and/or obviate the disadvantages of the conventional hydraulic flow control valve.
The main objective of the present invention is to provide an improved hydraulic flow control valve assembly that is a servo hydraulic flow control valve assembly.
To achieve the objective, the servo hydraulic flow control valve assembly in accordance with the present invention comprises an oil distribution board having a first manifold defined therein near an inlet end of the oil distribution board and a second manifold defined in the oil distribution board near an outlet end of the oil distribution board. A relief valve is secured on the oil distribution board, and includes a body positioned on the oil distribution board and a rated control device mounted to the body for selectively opening the first manifold. A servo control device is secured on the oil distribution board. The servo control device includes a controller rotatably received in the oil distribution board and having a passage defined to communicate with the second manifold. A control unit is secured on the oil distribution board for driving the controller to control the pressure and the flow rate in the second manifold.
Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.
Referring to the drawings and initially to
With reference to
With reference to
A third manifold (435) is defined in the oil distribution board (43) and corresponds to the cooling device (70). The third manifold (435) has a first end defining a backflow inlet (435A) communicating with the cooling device (70) and a second end defining a backflow outlet (435B) communicating with the fluid container (10).
The rated control device (411) opens the pipe set (30) and the fluid in the system flows back to the fluid container (10) via the relief inlet (432A), the body (412) and the relief outlet (432B) for releasing the pressure in the system when the pressure in the system over the rated pressure of the relief valve (41). The fluid in the system flows through the passage (424) in the controller (423) of the servo control device (42) via the second manifold (433) and achieve the purpose of fine turning when rotating the controller (423), thereby the fluid flows back to the fluid container (10) via the fine turning opening (433A) in the second manifold (433). The fluid is cooled in the cooling device (70) and flows back to the fluid container (10) via the reverse inlet (435A) and the reverse outlet (435B) of the third manifold (435) to form a closed circuit.
With reference to
As described above, the servo hydraulic flow control valve assembly in accordance with the present invention comprises the following advantages.
1. The convenience of the servo hydraulic flow control valve assembly is promoted. The servomotor (421) of the servo control device (42) can rotate the controller (423) to control the flow rate and the flow rate in the second manifold (433). As a result, the pressure in the main passage (431) is controller. Consequently, the servo hydraulic flow control valve assembly of the present invention can be wildly used in different field.
2. The relief valve (41) can provide an extra safety to the servo hydraulic flow control valve assembly because the relief valve (41) can quickly relief the pressure in the system.
3. The servo control device (42) can immediately slightly adjust the flow rate and the pressure in the system such that the system can quickly react when the flow rate and the pressure in the system us changed.
4. The buffer margin is raised. The servo control device (42) is used to slightly relief the pressure in the system such that the buffer margin is raised when the inputted pressure is greater than necessity.
Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.
