Pumps – Condition responsive control of drive transmission or pump... – Adjustable cam or linkage
Patent
1989-10-25
1991-03-19
Smith, Leonard E.
Pumps
Condition responsive control of drive transmission or pump...
Adjustable cam or linkage
F04B 128
Patent
active
050006665
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a control device for a variable displacement type compressor, said compressor comprising a housing having a plurality of cylinder bores arranged around a rotational driving shaft, an operating piston slidably fitted in each of said cylinder bores, a swashplate connected to said operating piston through a connecting rod, a holder supporting said swashplate, capable of being swung about an axis of a support shaft perpendicular to an axis of the rotational driving shaft and being connected to the rotational driving shaft, and a control piston connected to a sleeve and moved in response to pressure of a control pressure chamber in order to adjust an operating stroke of the operating piston by varying a position of angular displacement around the axis of the support shaft of said holder and said swashplate, a control valve being interposed among an intake chamber, a discharge chamber of said compressor and said control pressure chamber in order to control the discharge amount of the compressor in response to intake pressure.
TECHNICAL SUBJECT
In the past, such a control device as described above uses, for example, a control valve as shown in FIG. 3 to control pressure of a control pressure chamber. That is, an intake pressure Ps is introduced into an intake pressure chamber 64' around a bellows 71' into which atmospheric pressure is introduced, a push rod 59' having a base end connected to the bellows 71' is inserted into a passage hole 68' connecting a valve chamber 60' into which discharge pressure Pd is introduced and said intake pressure chamber 64' in order to drive a spherical valve body 57' encased in the valve chamber 60' to open and close between the valve chamber 60' and the passage hole 68', and a passage 53' on which control pressure Pc exerts is opened to the internal surface of an intermediate portion of the passage hole 68'.
In the above-described conventional device, when the intake pressure Ps exerting on the intake pressure chamber 64' is less than the set value, the bellows 71' expands, the valve body 57' is driven to be opened by the push rod 59' and the discharge pressure is introduced into the control pressure chamber. When the intake pressure Ps of the intake pressure chamber 64' becomes equal to or more than the set value, the bellows 71' is contracted, the valve body 57' is operated to be closed to cause the passage 53' to be communicated with the intake pressure chamber 64', and the control pressure Pc of the control pressure chamber is lowered.
However, when a section between the valve chamber 60' and the passage 53' is cut off, a section between the passage 53' and the intake pressure chamber 64 is communicated, and conversely when a section between the passage 53' and the intake pressure chamber 64' is cut off, a section between the valve chamber 60' and the passage 53' is communicated. Therefore, pressure of the control pressure chamber abruptly varies, and hunting occurs in variation in displacement of the compressor, thus deteriorating the driveability and durability.
DISCLOSURE OF THE INVENTION
The present invention has been accomplished in view of the foregoing. It is an object of the present invention to provide a control device for a variable displacement type compressor which prevents an occurrence of hunting in variation in displacement of a compressor.
According to the present invention, the control valve comprises a first valve mechanism capable of putting the discharge chamber and the control pressure chamber into and out of communication with each other and a second valve mechanism capable of putting the control pressure chamber and the intake chamber into and out of communication with each other, said first valve mechanism being opened when the pressure of the intake chamber is less than a first set pressure and closed when said pressure is equal to or more than the first set pressure, said second valve mechanism being opened when the pressure of the intake chamber is equal to or more than a second set pressure wh
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patent: 4231713 (1980-11-01), Widdowson et al.
patent: 4428718 (1984-01-01), Skinner
patent: 4688997 (1987-08-01), Suzuki et al.
patent: 4723891 (1988-02-01), Takenaka et al.
patent: 4932843 (1990-06-01), Itoigawa et al.
Honda Giken Kogyo Kabushiki Kaisha
Smith Leonard E.
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