Fluid controlling solenoid valve

Abstract

The present invention provides a fluid control electromagnetic valve which is not large-scale and can realize high temperature correction precision with a low cost. In the fluid control electromagnetic valve of the invention, the overlapping area of the position detecting coil (41) and the shielding body (42) is altered along with the relative movement. The impedance of the position detecting coil (41) is altered along with the alternation of the overlapping area. A signal processing circuit part outputs a sensor output voltage based on the impedance. The position of the valve is detected based on the value of the output voltage of the sensor. The signal processing circuit part takes out the alternation of resistance value based on the temperature alternation of a temperature correction resistor (50) as a correction voltage which is used for correcting the temperature of the sensor output voltage.

Description

technical field [0001] The present invention relates to a solenoid valve for fluid control which operates a valve section by utilizing electromagnetic attractive force generated in a solenoid section to control the flow rate of fluid. Background technique [0002] Conventionally, a solenoid valve for flow control that controls the flow rate of supply air to the engine by adjusting the opening degree of the valve by using an electromagnetic attractive force proportional to the excitation current flowing to the solenoid unit, a detection valve is known. The technology built into the valve position detection device of the position (for example, refer to Patent Document 1). [0003] The valve position detection device has: a position detection coil that generates magnetic flux; and a shielding body that moves relative to the position detection coil in conjunction with the movement of the valve and can shield the magnetic flux of the position detection coil. The voltage of the i...

AI Technical Summary

Problems solved by technology

[0005] In this kind of solenoid valve for flow control, the accuracy of flow control can be improved by detecting the position of the valve, but the position detection coil is arranged in the flow path, due to the change of fluid temperature and the heat from the engine, etc., the position detection coil The resistance value of the sensor changes, and the sensor output signal is affected by temperature fluctuations. As a result, there is a problem of deviation in flow path control.

[0006] Here, for example, by installing a temperature correction sensor such as a thermistor with a negative temperature characteristic in the signal processing circuit part, the influence of the temperature of the sensor output can be reduced, but there is a problem that the manufacturing cost increases due to the newly installed parts.

[0007] In addition, for example, if there is a characteristic deviation of the temperature correction sensor itself, and the temperature has a nonlinear characteristic, there is also the problem that the temperature correction is prone to error.

[0008] Furthermore, when the temperature correction sensor is installed at a position separated from the position detection coil arranged in the flow path, the detected temperatures detected by the temperature correction sensor and the position detection coil are different, and there is also a problem that the temperature correction accuracy decreases.

[0009] For this temperature difference, there is also a method of improving the temperature correction accuracy by installing the temperature correction sensor near the position detection coil, but in this case, space and equipment for installing the temperature correction sensor are required, and there are also problems of increase in size and manufacturing cost

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