JPH0112038Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a proportional electromagnetic valve for flow rate control that controls the flow rate of fluid in proportion to applied current.

The conventional structure of a proportional electromagnetic valve for flow rate control, which proportionally controls the flow rate of fluid using an applied current, is shown in FIG. That is, in the conventional structure shown in FIG. 1, a solenoid coil 2 wound around a bobbin 1 is housed in a cover 3, and is further magnetically coupled to a core 4 located inside the bobbin 1. The cover 3 is
mechanically fixed inside. A cylindrical pipe 6 made of a non-magnetic material is inserted into the bobbin 1, and the core 4 is inserted into the pipe 6.
A valve 7, which is magnetically attracted to the valve 7, is slidably inserted in the axial direction of the valve 7. This valve 7 is block 8
It opens and closes a flow rate control port 11 provided in a pipe 6 that communicates with an inflow passage 9 and an outflow passage 10 which are formed into a shape. The lower ends of the pipe 6 and the valve 7 are pressed against the upper surface of the seat 13, and the lower end of the valve 7 is elastically pressed onto the seat 13 by a spring 12. This sheet 1
A fluid passageway communicating the flow rate control port 11 and the outflow passageway 10 is provided at the center of the housing 3 . Also, a hole 20 is bored in the block 8 to connect the inlet passage 9 and the outlet passage 10. In addition, in the center of the core 4,
There is an adjustment screw 14 for the spring 12. The valve 7 forms a magnetic circuit with a sleeve 15, a cover 3, a core plate 5, and a core 4 via a pipe 6. Nao 16, 17
indicates an O-ring, and 18 indicates magnetic flux.

Before the solenoid coil 2 is energized, the valve 7 is pressed against the seat 13 by the elastic force of the spring 12 installed between the core 4 and the valve 7, so the flow rate control port 11 of the pipe 6 is It is closed, allowing fluid to flow only through the hole 20. When the solenoid coil 2 is energized now, the valve 7 operates due to the magnetic attraction force of the core 4 that follows the magnitude of the applied current, and stops when the repulsive force of the spring 12 is balanced. Since the opening area of the flow control port 11 is changed by the operation of the valve 7, a flow rate proportional to the applied current can be obtained.

One of the flow characteristics required for proportional solenoid valves is the second
There are some as shown in the figure. That is, the current value is 0 to I ₁
Between I1 and I2, the flow rate _Q1 is constant, and between _I1 and _I2 , it is proportional to _Q1 and _Q2 . In order to make the flow rate _Q1 start to change when the current exceeds _I1 , the magnitude of the initial set load of the spring 12 shown in FIG. 1 is set using the adjustment screw 14. Current I ₁
The magnetic attraction force between the core 4 and the valve 7 at is equal to the initial set load of the spring 12,
When the current is _I1 or more, it is important that the current value and the stroke of the valve 7 are proportional. However, the actual flow rate characteristics had the drawback of being unstable, as shown by the broken line in the graph. The reason for this is that the current I ₁ is small and the core 4
Since the distance between the valve 7 and the valve 7 is large, the magnetic attraction force acting on the valve 7 is small, and the inflow passage 9 and the outflow passage 1
This is because the pressure difference between 0 and 0 acts subtly when the valve 7 begins to open, and the flow rate is in a transient state where the flow starts from zero.

The present invention has been made to eliminate such drawbacks, and provides a proportional solenoid valve that can improve flow characteristics by providing unevenness on at least one of the contact surfaces between the valve and the seat instead of the conventional holes 20. The purpose is to provide

The present invention will be explained in detail below based on the embodiment shown in FIG.

The gist of the present invention is the groove 19 provided in the block 8' and the seat 13' without the hole 20, and the other structures can be applied as they are, so parts common to the conventional example are designated by the same reference numerals. The explanation will be omitted.

That is, by the groove 19 provided on the upper surface of the sheet 13',
Even if the current applied to the solenoid coil 2 is zero, the flow rate Q ₁ is flowing. When the current increases to I ₁ , the magnetic attraction force acting on valve 7 is applied to spring 1.
When the current is equal to the set load in Figure 2 and further increases, valve 7 opens, but since there is a flow between valve 7 and seat 13' from the beginning, valve 7 opens smoothly and the flow rate is the same as the solid line in Figure 2. Stable properties can be obtained.

As described above, in the first embodiment of the present invention, the groove 19 is provided on the upper surface of the sheet 13' as shown in FIG. The unevenness may be added to the valve side.

As described above, in the present invention, when the solenoid is not energized, the repulsive force of the spring causes the valve in the pipe to be pressed against the seat with the fluid passage in the center, blocking the fluid control port provided in the pipe, and when the solenoid is energized, the spring In a proportional solenoid valve in which the valve is attracted by the core until it reaches a position balanced with the repulsive force and the flow control port is opened to obtain a predetermined flow rate, at least one of the contact surfaces between the valve and the seat is provided upstream and downstream of the flow control port. Since this is a proportional solenoid valve characterized by having grooves or unevenness that communicate with This has the effect of providing a proportional solenoid valve with low and stable flow characteristics.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional proportional solenoid valve, Fig. 2 is a graph showing an example of flow characteristics, Fig. 3 is a sectional view showing an embodiment of a proportional solenoid valve according to the present invention, and Fig. The figure is a perspective view showing an example of only the sheet. 2: Solenoid, 4: Core, 6: Pipe,
7: Valve, 11: Flow control port, 12: Spring, 13, 13': Seat, 19: Groove.

Claims (1)

[Claim for Utility Model Registration] When the solenoid is not energized, the repulsive force of the spring causes the valve in the pipe to be pressed against the seat with a fluid passage in the center, blocking the flow control port provided in the pipe, and when energized, the spring In a proportional solenoid valve that opens the flow control port and obtains a predetermined flow rate when the valve is attracted by the core to a position balanced with the repulsive force of 1. A proportional solenoid valve characterized by having grooves or depressions communicating with the downstream side.