US 4,593,881 AGranted

Electronic expansion valve

AssigneeSystem Homes Company, Ltd.

InventorHozo Yoshino

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Abstract

An electronic expansion valve comprising a stepping motor, motion conversion member for converting the rotational motion of the stepping motor to a screw motion, a valve pintle coupled to the motion conversion means to be rectilinearly displaced and having pistons at both ends of the valve pintle, of which the pistons are slidably supported on valve casing members, a valve body formed as an integral part of the valve pintle at an intermediate portion thereof, and a valve seat which has such an outer surface that when the valve pintle is displaced with respect to the valve seat in either direction, the cross sectional area and the shape of a passage defined between the valve seat and the valve pintle are smoothly varied. The valve can be used in refrigeration cycle with a compressor. Stable operation of the refrigeration cycle is obtained. The orifice contour created by a moving valve body and a valve seat is always maintained streamlined so that the friction loss therethrough is substantially reduced, whereby the coefficient of performance of the refrigeration cycle is improved.

Claims10

Dependent claims

An electronic expansion valve for use in a vapor compression refrigeration cycle to generate a desired pressure difference across a passage of said expansion valve for a given refrigerant mass flow, comprising:

(a) a valve casing having a longitudinal bore;
(b) a stepping motor having a threaded output shaft mounted on one end of said valve casing and being driven in a digital fashion;
(c) a motion conversion member housed coaxially inside said valve casing and threadedly coupled to said output shaft of said stepping motor for converting the rotational motion of said stepping motor to an axial motion of said motion conversion member;
(d) a valve pintle fixedly coupled to said motion conversion member to be axially displaced and having pistons at both ends of said valve pintle, said pistons being slidably supported on said valve casing in a coaxial relation with the longitudinal axis thereof;
(e) a valve body formed as an integral part of said valve pintle at an intermediate position thereof and in the form of a spindle;
and
(f) a valve seat comprising a part of the surface of said bore inside said valve casing in the form of a venturi and having an outer surface such that when said valve pintle is axially displaced with respect to said valve seat in either direction, the cross sectional area and the shape of the passage defined between said valve seat and said valve body are so varied that the inverse of the orifice area squared has a linear relationship with the stroke of said valve pintle whereby the relationship between the pressure difference across said valve body and said stroke is substantially linear.

4 more elements

(a) a valve casing having a longitudinal bore;
(b) a stepping motor having a threaded output shaft mounted on one end of said valve casing and being driven in a digital fashion;
(c) a motion conversion member housed coaxially inside said valve casing and threadedly coupled to said output shaft of said stepping motor for converting the rotational motion of said stepping motor to an axial motion of said motion conversion member;
(d) a valve pintle fixedly coupled to said motion conversion member to be axially displaced and having one piston at one end thereof, said one piston slidably supported on said valve casing in a coaxial relation with the longitudinal axis of said valve casing, the other end of said valve pintle having a free end and forming an orifice with said valve seat;
(e) a valve body formed as an integral part of said valve pintle at an intermediate position thereof and in the form of a spindle;
and
(f) a valve seat comprising a part of the surface of said bore inside said valve casing in the form of a venturi and having an outer surface such that when said valve pintle is axially displaced with respect to said valve seat in either direction, the cross sectional area and the shape of the passage defined between said valve seat and said valve body are so varied that the inverse of the orifice area squared has a linear relationship with the stroke of said valve pintle whereby the relationship between the pressure difference across said valve body and said stroke is substantially linear.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/777,864Filed 19 Sep 1985 · continuation
Priority: JP 57-18735827 Oct 1982
Granted: 10 Jun 1986
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

F25B 41/35
With the valve member being actuated by electric means, e.g. by piezoelectric actuators: by rotary motors, e.g. by stepping motors
F25B 41/38
Expansion means; Dispositions thereof: specially adapted for reversible cycles, e.g. bidirectional expansion restrictors
F25B 2500/01
Problems to be solved: geometry problems, e.g. for reducing size
F25B 2600/2513
Control of valves: expansion valves