Control valve for variable displacement compressor

• US 7,381,031 B2
• Filed: 01/25/2005
• Issued: 06/03/2008
• Est. Priority Date: 01/29/2004
• Status: Active Grant

• Current Assignee: TGK Co. Ltd.
• Original Assignee: TGK Co. Ltd.
• Inventors: Kajiwara, Morimitsu, Kawaguchi, Takeshi
• Primary Examiner(s): Freay; Charles G.
• Assistant Examiner(s): DWIVEDI, VIKANSHA S
• Application Number:
  US11/041,226
• Publication Number:
  US 20050169768A1
• Time in Patent Office: 1,225 Days
• Field of Search: 417/222.2, 251/129.15, 251/129.16
• US Class Current: 417/222.2
• CPC Class Codes: F04B 2027/1827 between crankcase and discharge chamber
• CPC Class Codes: F04B 2027/1854 External parameters
• CPC Class Codes: F04B 2027/1859 Suction pressure
• CPC Class Codes: F04B 27/1804 Controlled by crankcase pressure

Abstract

A control valve for a variable displacement compressor that is mounted on the variable displacement compressor to control pressure within a hermetic crankcase to thereby change the discharging capacity of a refrigerant.

Claims

1. A control valve for a variable displacement compressor, which is mounted on the variable displacement compressor to control pressure within a hermetic crankcase thereof to thereby change discharging capacity of refrigerant, comprising:

a body having a refrigerant passage formed therethrough;

a valve section including a valve element moving to and away from a valve seat formed in the body so as to adjust a flow rate of refrigerant when part of refrigerant discharged from the variable displacement compressor is caused to flow into the crankcase, and a shaft configured to be axially slidably supported by the body and support the valve element such that the valve element can be caused to operate in unison therewith; and

a solenoid including a core fixed within the body, a plunger for moving the valve element forward and backward within the body via the shaft so as to cause the valve element to open and close, and a solenoid coil for generating a magnetic circuit including the plunger and the core by electric current supplied from outside,

wherein the plunger is formed by arranging a first plunger opposed to the core, and a second plunger to which an end of the shaft, opposite to the valve element, is connected, in series in an axial direction, the plunger being formed by arranging a pressure-sensing member for sensing suction pressure from a suction chamber, and a hollow cylindrical magnetic member for fixing the pressure-sensing member to the solenoid, between the first and second plungers,

wherein the first plunger is configured to be urged in a direction away from the core, and support the second plunger in an axial direction when the solenoid is energized, and

wherein the second plunger includes a small-diameter portion inserted into the magnetic member such that a predetermined space is formed therebetween, and a large-diameter portion radially outwardly extending from the small-diameter portion and having an opposed surface formed thereon which is axially opposed to an opposed surface of the magnetic member, the second plunger being urged in a direction away from the first plunger, while the magnetic circuit being formed via the opposed surfaces during energization of the solenoid.

2. The control valve for a variable displacement compressor according to claim 1, wherein an elastic member formed of a non-magnetic material for urging the second plunger in the direction away from the first plunger is disposed between the small-diameter portion of the second plunger and the magnetic member.

3. The control valve for a variable displacement compressor according to claim 1, wherein the first plunger and the core have respective tapered surfaces having complementary shapes to each other formed on opposed surfaces thereof.

4. The control valve for a variable displacement compressor according to claim 1, wherein the second plunger and the magnetic member have respective tapered surfaces having complementary shapes to each other formed on the opposed surfaces thereof.