Unlock instant, AI-driven research and patent intelligence for your innovation.

Piston-type variable displacement compressor

a variable displacement compressor and compressor technology, applied in the direction of positive displacement liquid engines, pump control, machines/engines, etc., can solve the problems of generating noise, reducing the amount of gas passing through the suction valve, and reducing the pressure of the suction valve, so as to achieve the effect of reducing the fluctuation of pressur

Inactive Publication Date: 2005-11-03
TOYOTA IND CORP
View PDF8 Cites 7 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a piston-type variable displacement compressor that can mitigate fluctuation in pressure during variable displacement operation without affecting maximum displacement operation. This is achieved by adjusting the stroke of the pistons in the cylinder bores through the use of a rotary valve with a guide passage for introducing a suction gas into the operation chambers in the cylinder bores. The rotary valve includes a spool that is axially movable under the suction chamber pressure and the crank chamber pressure, which is caused to retract during maximum displacement operation to make both the main suction port and the sub suction port totally open, and which advances during variable displacement operation to close the main suction port, so that suction is effected solely through the sub suction port.

Problems solved by technology

However, when the flow rate is low, the amount of gas passing through the suction valve is reduced, so that self-excited vibration of the suction valve is liable to be caused in a free vibration region where the suction valve does not abut a stopper.
When such self-excited vibration is generated, a fluctuation in pressure is generated and propagated to an evaporator connected to the compressor, which may lead to generation of noise.
As the pressure of the crank chamber becomes higher than the pressure of the suction chamber, the rotary valve is moved against the urging force of the spring, and the opening area increases, thus resulting in an increase in flow rate.
Therefore, during maximum displacement operation, in particular, it is necessary to greatly compress the spring to increase the opening area to a maximum degree, so that there is a fear of involving a deterioration in performance of the compressor.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Piston-type variable displacement compressor
  • Piston-type variable displacement compressor
  • Piston-type variable displacement compressor

Examples

Experimental program
Comparison scheme
Effect test

embodiment 1

[0018]FIG. 1 shows a construction of a piston-type variable displacement compressor according to Embodiment 1. A front housing 2 is connected to the front end portion of a cylinder block 1, and a rear housing 4 is connected to the rear end portion of the cylinder block 1 through the intermediation of a valve forming member 3. A crank chamber 5 is defined by the cylinder block 1 and the front housing 2, and a drive shaft 6 is rotatably supported by the cylinder block 1 and the front housing 2 so as to extend through the crank chamber 5. The forward end portion of the drive shaft 6 protrudes outwardly from the front housing 2 and is connected to a rotary drive source (not shown), such as a vehicle engine or a motor. Inside the front housing 2, a rotary support member 7 is fixed to the drive shaft 6, and a swash plate 8 is mounted so as to be engaged with the rotary support member 7. The swash plate 8 has at its center a through-hole, through which the drive shaft 6 extends, and, in th...

embodiment 2

[0033]FIG. 4 shows the construction of the rotary valve of a piston-type variable displacement compressor according to Embodiment 2. In the cylindrical chamber 22, a first spool 29 is movably accommodated, and, on the rear side of the first spool 29, a second spool 30 is movably accommodated. Between the first spool 29 and the second spool 30, there is arranged a spring 31. The pressure Ps of the suction chamber 15 acts on the front surface of the first spool 29, and the pressure Pc of the crank chamber 5 acts on the rear surface of the second spool 30. Otherwise, this embodiment is of the same construction as Embodiment 1.

[0034] During maximum displacement operation, the pressure Pc of the crank chamber 5 is substantially equal to the pressure Ps of the suction chamber 15, so that the first spool 29 is pushed within the cylindrical member 22 toward the bottom portion 22a by the suction gas flow, and retracts together with the second spool 30. As a result, as shown in FIG. 4, both ...

embodiment 3

[0037]FIG. 6 shows a construction of the rotary valve of a piston-type variable displacement compressor according to Embodiment 3. In Embodiment 3, Embodiment 1 shown in FIGS. 1 through 3 is modified such that, instead of the main suction port 23, there are formed in the cylindrical member 22 of the rotary valve 21 a first suction port 32 for securing the flow rate corresponding to maximum displacement operation, and a second suction port 33 adjacent to the first suction port 32 so as to be on the leading side with respect to the rotating direction of the rotary valve. The first suction port 32 has an opening area S3, and the second suction port 33 has an opening area S4 that is smaller than the opening area S3 of the first suction port 32. Further, the sub suction port 24 is formed so as to be axially adjacent to the first suction port 32. Otherwise, this embodiment is of the same construction as Embodiment 1.

[0038] Since the second suction port 33 having the small opening area S4...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

In a piston-type variable displacement compressor according to the present invention, a rotary valve includes a guide passage having a main suction port for securing a flow rate corresponding to maximum displacement operation and a sub suction port for effecting throttling to a flow rate low enough to suppress pressure fluctuation during variable displacement operation, and during maximum displacement operation, the spool is moved by a suction gas flow to totally open both the main suction port and the sub suction port, and during variable displacement operation, the spool is moved by a pressure difference between the suction chamber pressure and the crank chamber pressure to close the main suction port while keeping the sub suction port open.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a piston-type variable displacement compressor, and more particularly to a reduction in pressure fluctuation during variable displacement operation. [0003] 2. Description of the Related Art [0004] In a piston-type variable displacement compressor, in which pistons reciprocate within cylinder bores as a drive shaft rotates, it is possible to vary the displacement through variable control of the piston stroke. However, when the flow rate is low, the amount of gas passing through the suction valve is reduced, so that self-excited vibration of the suction valve is liable to be caused in a free vibration region where the suction valve does not abut a stopper. When such self-excited vibration is generated, a fluctuation in pressure is generated and propagated to an evaporator connected to the compressor, which may lead to generation of noise. [0005] For example, JP 7-324678 A discloses a c...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(United States)
IPC IPC(8): F04B27/14F04B27/08F04B27/10F04B49/22
CPCF04B27/1018F04B49/225F04B27/1036
Inventor HAYASHI, SHIROHIBINO, SOKICHIKITA, YUSUKETASHIRO, TOMOHARU
Owner TOYOTA IND CORP