EP0907021B1 - Displacement control valve for use in a variable displacement compressor - Google Patents
Displacement control valve for use in a variable displacement compressor Download PDFInfo
- Publication number
- EP0907021B1 EP0907021B1 EP19980118560 EP98118560A EP0907021B1 EP 0907021 B1 EP0907021 B1 EP 0907021B1 EP 19980118560 EP19980118560 EP 19980118560 EP 98118560 A EP98118560 A EP 98118560A EP 0907021 B1 EP0907021 B1 EP 0907021B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- valve
- pressure
- displacement control
- control valve
- communication passage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B27/00—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders
- F04B27/08—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders having cylinders coaxial with, or parallel or inclined to, main shaft axis
- F04B27/14—Control
- F04B27/16—Control of pumps with stationary cylinders
- F04B27/18—Control of pumps with stationary cylinders by varying the relative positions of a swash plate and a cylinder block
- F04B27/1804—Controlled by crankcase pressure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B27/00—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders
- F04B27/08—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders having cylinders coaxial with, or parallel or inclined to, main shaft axis
- F04B27/14—Control
- F04B27/16—Control of pumps with stationary cylinders
- F04B27/18—Control of pumps with stationary cylinders by varying the relative positions of a swash plate and a cylinder block
- F04B27/1804—Controlled by crankcase pressure
- F04B2027/1809—Controlled pressure
- F04B2027/1813—Crankcase pressure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B27/00—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders
- F04B27/08—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders having cylinders coaxial with, or parallel or inclined to, main shaft axis
- F04B27/14—Control
- F04B27/16—Control of pumps with stationary cylinders
- F04B27/18—Control of pumps with stationary cylinders by varying the relative positions of a swash plate and a cylinder block
- F04B27/1804—Controlled by crankcase pressure
- F04B2027/1822—Valve-controlled fluid connection
- F04B2027/1827—Valve-controlled fluid connection between crankcase and discharge chamber
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B27/00—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders
- F04B27/08—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders having cylinders coaxial with, or parallel or inclined to, main shaft axis
- F04B27/14—Control
- F04B27/16—Control of pumps with stationary cylinders
- F04B27/18—Control of pumps with stationary cylinders by varying the relative positions of a swash plate and a cylinder block
- F04B27/1804—Controlled by crankcase pressure
- F04B2027/184—Valve controlling parameter
- F04B2027/1859—Suction pressure
Definitions
- the present invention relates to a displacement control valve for use in a variable displacement compressor which is included in, for example, a vehicle air conditioner.
- variable displacement compressor there has been a type having a piston.
- the compressor of the type comprises a crank chamber, a suction chamber, and a discharge chamber.
- the piston has a piston stroke controlled in response to the pressure in the crank chamber. Therefore, the compressor has a displacement which is variable and determined in accordance with the piston stroke.
- a displacement control valve is assembled to the variable displacement compressor to control the piston stroke.
- Various displacement control valves have been known in the art.
- the shown displacement control valve monitors the pressure in the suction chamber by means of a bellows 1 and opens/closes a ball valve 2 depending on the monitored suction chamber pressure so as to adjust the amount of gas introduced into the crank chamber from the discharge chamber.
- This is a bellows valve structure of a so-called internal control type.
- an electromagnetic actuator 3 is further disposed over the ball valve 2 so that an electromagnetic force is exerted on the ball valve 2.
- the operation point of the bellows valve i.e. the pressure control point of the suction chamber, can be changed according to the current amount supplied to the electromagnetic actuator 3.
- the suction chamber pressure control point changes, as shown in Fig. 8, depending on discharge chamber pressures Pd1, Pd2, Pd3, ... even if the current amount fed to the electromagnetic actuator 3 is constant. Accordingly, the suction chamber pressure control point can not be determined univocally relative to the current amount fed to the electromagnetic actuator 3, so that a control method becomes complicated for optimally controlling the discharge displacement of the compressor.
- suction chamber pressure can not be controlled over 3.7kg/cm 2 G.
- the pressure in the suction chamber is controlled across 2kg/cm 2 G so that no problem is raised.
- the discharge displacement may be reduced for enhancing the acceleration performance.
- the discharge displacement is reduced while the pressure in the suction chamber increases.
- the pressure in the suction chamber increases up to 3.7kg/cm 2 G, the discharge displacement is controlled to keep this pressure. Accordingly, depending on the vehicle operating condition, the required minimum displacement can not be achieved to given a serious influence onto the vehicle running performance.
- a displacement control valve for use in a variable displacement compressor comprising a suction chamber, a crank chamber and a discharge chamber.
- the displacement control valve comprises a valve casing defining a communication passage for communicating the discharge chamber with the crank chamber, a valve member placed in the communication passage, and moving means for moving the valve member.
- the valve member has a first and second surface.
- a solenoid chamber is-provided which receives the pressure of the crank chamber as rear pressure against the valve member.
- variable displacement compressor including a displacement control valve according to a first embodiment of the present invention.
- the shown compressor is used for a vehicle air conditioner and comprises a tubular casing 31, a front housing 32 closing one axial end of the casing 31, and a cylinder head 34 attached to the other axial end of the casing 31 via a valve plate assembly 33.
- the casing 31, the front housing 32 and the cylinder head 34 are fixed together by means of bolts 35.
- the casing 31 is integrally provided with a cylinder block 36 therein.
- a shaft 37 axially extends at the center of the casing 31.
- the shaft 37 is rotatably supported by the front housing 32 and the cylinder block 36.
- a pulley 38 is rotatably supported on the front housing 32.
- the pulley 38 is driven by an engine of the vehicle.
- a ring-shaped armature 41 is supported on an outer end of the shaft 37 via a rubber member 39 so as to be movable axially.
- the armature 41 confronts an axial end surface of the pulley 38 and is controlled to be attached to or detached from the pulley 38 by means of an electromagnetic attracting unit 42. Specifically, when the electromagnetic attracting unit 42 is energized, the armature 41 is attracted and attached to the pulley 38 by an electromagnetic force, so that the torque of the engine is transmitted to the shaft 37. On the other hand, when the energization to the electromagnetic attracting unit 42 is stopped, the armature 41 is detached from the pulley 38 by a restoring force of the rubber member 39, so that the torque of the engine is not transmitted to the shaft 37.
- a crank chamber 43 is defined between the front housing 32 and the cylinder block 36.
- a rotor 44 is fixed on the shaft 37.
- a swash plate 46 is coupled to the rotor 44 via a hinge mechanism 45.
- the hinge mechanism 45 renders variable an inclination of the swash plate 46 relative to an axis of the shaft 37.
- the swash plate 46 rotates together with the rotor 44.
- a plurality of pistons 47 engage with peripheral portions of the swash plate 46 via shoes, respectively.
- the pistons 47 are received in corresponding cylinder bores 48 formed in the cylinder block 36 so as to be axially slidable.
- each of the pistons 47 makes a reciprocating motion in the corresponding cylinder bore 48 with a stroke determined by an inclination of the swash plate 46.
- the cylinder head 34 is formed with a suction chamber 51 along its peripheral portion and with a discharge chamber 52 at the center thereof. Between the suction chamber 51 and the discharge chamber 52 is connected a known refrigeration circuit.
- the valve plate assembly 33 is provided with suction holes 53 and discharge holes 54 for establishing communication of the cylinder bores 48 with the suction chamber 51 and the discharge chamber 52, and with valve mechanisms for those holes.
- variable displacement compressor depends on the stroke of the pistons 47 determined by the inclination of the swash plate 46.
- a displacement control valve 10 is further provided in a control valve chamber 55 formed in the cylinder head 34.
- the control valve chamber 55 communicates with the crank chamber 43, the suction chamber 51 and the discharge chamber 52 via passages 56, 57 and 58, respectively. Further, the suction chamber 51 communicates with the crank chamber 43 via a narrow passage 59.
- the displacement control valve 10 adjusts the pressure in the crank chamber 43 so as to control the stroke of the pistons 47.
- the displacement control valve 10 comprises a valve casing 11 and a bellows 12 disposed in the valve casing 11.
- the inside of the bellows 12 is under vacuum and provided with a spring.
- the displacement control valve 10 further comprises a guide 13 receiving a lower end (in the figures) of the bellows 12 and disposed in a cavity of the valve casing 11 so as to be movable, a spring 14 for biasing the guide 13 upward (in the figures), an adjusting screw 15 forming a part of the valve casing 11 and adjusting the expansion/ contraction amount of the bellows 12, a transfer rod 16 engaging at its one end with an upper end (in the figures) of the bellows 12 and supported by the valve casing 11 so as to be movable, a valve member 18 engaging with the other end of the transfer rod 16 so as to open/close a communication passage 17 between the discharge chamber 52 and the crank chamber 43 depending on the expansion/contraction of the bellows 12, and an electromagnet assembly comprising an electromagnetic coil 21 and a core 24 for generating an electromagnetic force urging the valve member 18 in a valve closing direction via a plunger 19 and a transfer rod 20.
- a combination of the electromagnetic coil 21, the core 24, the plunger 19 and the transfer rod 20 is
- the communication passage 17 comprises an inlet portion 17a communicated with the discharge chamber 52 through the passage 58, a plurality of outlet portions 17b communicated with the crank chamber 43 through the passage 56, and an intermediate portion 17c between the inlet portion 17a and the outlet portions 17b.
- the intermediate portion 17c is formed with a valve seat 17d radially extended.
- the valve member 18 has a first surface 18a facing the valve seat 17d and a second surface 18b facing a rear chamber 25 provided as a recessed portion at the bottom of the core 24.
- first surface 18a rests on the valve seat 17d
- second surface 18b is arranged to receive the pressure of the crank chamber 43 via the rear chamber 25 and a pressure introducing passage 22 which is made to the valve casing 11.
- Crank chamber pressure receiving areas of the first surface and the second surfaces 18a and 18b are set equal to each other when the first surface 18a of the valve member 18 rests on the valve seat.
- a circumference surface 18c of the valve member 18 is supported by the valve casing 11 so as to be movable with a gap therebetween set to be minimum.
- the valve casing 11 has a plurality of lateral holes 11a.
- the adjusting screw 15 has a through hole 15a.
- Each of the lateral holes 11a and the through hole 15a communicates the cavity of the valve casing 11 with the suction chamber 51 through the passage 57 and the control valve chamber 55. Therefore, the cavity of the valve casing 11 is subjected to the pressure of the suction chamber 51.
- the biasing force of the spring 14 is set to be small, for example, smaller than an electromagnetic force generated by a current value i0(A) supplied to the electromagnetic coil 21.
- the valve member 18 can be closed in a current region of i0(A) or greater.
- the bellows 12 As the pressure in the suction chamber 51 is lowered, the bellows 12 is expanded to cause a lower end (in the figures) of the guide 13 to abut the adjusting screw 15, so that a function of the spring 14 is lost. At this time, the pressure in the crank chamber 43 applied to the valve member 18 is canceled at the sides of the first and the second surfaces 18a and 18b, and the pressure in the discharge chamber 52 does not work in an axial direction of the valve member 18. Accordingly, the valve member 18 is open/close controlled depending on the electromagnetic force and the pressure in the suction chamber 51 applied to the bellows 12. Specifically, when the pressure in the suction chamber 51 is lowered to 2kg/cm 2 G, the bellows 12 is expanded to move the valve member 18 in a valve opening direction.
- the gas in the discharge chamber 52 is introduced into the crank chamber 43 to increase a pressure differential between the crank chamber 43 and the suction chamber 51, so that the discharge displacement is reduced.
- the bellows 12 is contracted to move the valve member 18 in the valve closing direction. Accordingly, the pressure in the crank chamber 43 is lowered to reduce a pressure differential between the crank chamber 43 and the suction chamber 51, so that the discharge displacement increases.
- the opening degree of the valve member 18 is adjusted to converge the pressure in the suction chamber 51 to a given value, so that the discharge displacement is controlled.
- the pressure control point of the suction chamber 51 is univocally determined by a value of current supplied to the electromagnetic coil 21. If the current value is set to be zero in this state, the bellows 12 is expanded to cause the valve member 18 to be fully open.
- the minimum displacement is realized. Even if this increases the pressure in the suction chamber 51 up to greater than 3.5kg/cm 2 G in Fig. 3 to contract the bellows 12, since the valve member 18 is urged upward (in the figures) by the spring 14 to be constantly opened, the compressor is kept at the minimum displacement.
- Fig. 4 the description will be directed to a displacement control valve according to a second embodiment of the present invention. Similar parts are designated by like reference numerals.
- the pressure introducing passage 22 is made to penetrate the valve member 18 in the upward and downward direction of the figure.
- Fig. 5 the description will be directed to a displacement control valve according, to a third embodiment of the present invention. Similar parts are designated by like reference numerals.
- the valve member 18 is slidably fitted in the intermediate portion 17c of the communication passage 17.
- the inlet portion 17a of the communication passage 17 is opened or closed in response to movement of the valve member 18 in the upward and downward direction in the figure.
- Fig. 6 the description will be directed to a displacement control valve according to a fourth embodiment of the present invention. Similar parts are designated by like reference numerals. Also in the displacement control valve, the pressure introducing passage 22 is made to penetrate the valve member 18 in the upward and down ward direction of the figure.
- the bellows may expands/contracts in response to a pressure in at least one of the suction chamber and the crank chamber.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
- Control Of Positive-Displacement Pumps (AREA)
Description
- The present invention relates to a displacement control valve for use in a variable displacement compressor which is included in, for example, a vehicle air conditioner.
- As such a variable displacement compressor, there has been a type having a piston. In the manner known in the art, the compressor of the type comprises a crank chamber, a suction chamber, and a discharge chamber. The piston has a piston stroke controlled in response to the pressure in the crank chamber. Therefore, the compressor has a displacement which is variable and determined in accordance with the piston stroke.
- For making the displacement be variable, a displacement control valve is assembled to the variable displacement compressor to control the piston stroke. Various displacement control valves have been known in the art.
- Referring now to Fig. 7, description will be made as regards an example of the conventional displacement control valves. The shown displacement control valve monitors the pressure in the suction chamber by means of a
bellows 1 and opens/closes aball valve 2 depending on the monitored suction chamber pressure so as to adjust the amount of gas introduced into the crank chamber from the discharge chamber. This is a bellows valve structure of a so-called internal control type. - On the basis of the bellows valve structure of this type, an
electromagnetic actuator 3 is further disposed over theball valve 2 so that an electromagnetic force is exerted on theball valve 2. Thus, the operation point of the bellows valve, i.e. the pressure control point of the suction chamber, can be changed according to the current amount supplied to theelectromagnetic actuator 3. - However, in the displacement control valve shown in Fig. 7, since the
ball valve 2 is subject to the discharge chamber pressure, the suction chamber pressure control point changes, as shown in Fig. 8, depending on discharge chamber pressures Pd1, Pd2, Pd3, ... even if the current amount fed to theelectromagnetic actuator 3 is constant. Accordingly, the suction chamber pressure control point can not be determined univocally relative to the current amount fed to theelectromagnetic actuator 3, so that a control method becomes complicated for optimally controlling the discharge displacement of the compressor. - According to the structure shown in Fig. 7, there should be an upper limit in suction chamber pressure. For example, in Fig. 8, the suction chamber pressure can not be controlled over 3.7kg/cm2G.
- During the normal running of the vehicle, the pressure in the suction chamber is controlled across 2kg/cm2G so that no problem is raised. On the other hand, during acceleration of the vehicle, the discharge displacement may be reduced for enhancing the acceleration performance. In this case, the discharge displacement is reduced while the pressure in the suction chamber increases. When the pressure in the suction chamber increases up to 3.7kg/cm2G, the discharge displacement is controlled to keep this pressure. Accordingly, depending on the vehicle operating condition, the required minimum displacement can not be achieved to given a serious influence onto the vehicle running performance.
- From DE 197 16 089 A1 a displacement control valve for use in a variable displacement compressor comprising a suction chamber, a crank chamber and a discharge chamber is known. The displacement control valve comprises a valve casing defining a communication passage for communicating the discharge chamber with the crank chamber, a valve member placed in the communication passage, and moving means for moving the valve member. The valve member has a first and second surface. A solenoid chamber is-provided which receives the pressure of the crank chamber as rear pressure against the valve member.
- Therefore, it is an object of the present invention to provide a displacement control valve which makes it possible to determine the suction chamber pressure control point univocally relative to the current amount fed to an electromagnetic actuator and which makes it possible to forcibly keep the required minimum displacement of the variable displacement compressor in the state wherein no current is fed to the electromagnetic actuator.
- Such an object is solved by a displacement control valve according to the
independent claim 1. - Preferred developments are given in the dependent claims.
- Fig. 1 is a longitudinal sectional view showing the overall structure of a variable displacement compressor;
- Figs. 2A and 2B are longitudinal sectional views of a displacement control valve according to a first embodiment of the present invention, wherein Fig. 2A shows the state of a normal operation of the compressor while Fig. 2B shows the state of the minimum displacement of the compressor;
- Fig. 3 is a graph showing a pressure control characteristic of the displacement control valve shown in Figs. 2A and 2B;
- Fig. 4 is a longitudinal sectional view of a displacement control valve according to a second embodiment of the present invention;
- Fig. 5 is a longitudinal sectional view of a displacement control valve according to a third embodiment of the present invention;
- Fig. 6 is a longitudinal sectional view of a displacement control valve according to a fourth embodiment of the present invention; Fig. 7 is a longitudinal sectional view of a conventional displacement control valve; and
- Fig. 8 is a graph showing a pressure control characteristic of the displacement control valve shown in Fig. 7.
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- Referring to Fig. 1, description will at first be made as regards a variable displacement compressor including a displacement control valve according to a first embodiment of the present invention.
- The shown compressor is used for a vehicle air conditioner and comprises a
tubular casing 31, afront housing 32 closing one axial end of thecasing 31, and acylinder head 34 attached to the other axial end of thecasing 31 via avalve plate assembly 33. Thecasing 31, thefront housing 32 and thecylinder head 34 are fixed together by means ofbolts 35. - The
casing 31 is integrally provided with acylinder block 36 therein. Ashaft 37 axially extends at the center of thecasing 31. Theshaft 37 is rotatably supported by thefront housing 32 and thecylinder block 36. - A
pulley 38 is rotatably supported on thefront housing 32. Thepulley 38 is driven by an engine of the vehicle. A ring-shaped armature 41 is supported on an outer end of theshaft 37 via arubber member 39 so as to be movable axially. - The
armature 41 confronts an axial end surface of thepulley 38 and is controlled to be attached to or detached from thepulley 38 by means of an electromagnetic attractingunit 42. Specifically, when the electromagnetic attractingunit 42 is energized, thearmature 41 is attracted and attached to thepulley 38 by an electromagnetic force, so that the torque of the engine is transmitted to theshaft 37. On the other hand, when the energization to the electromagnetic attractingunit 42 is stopped, thearmature 41 is detached from thepulley 38 by a restoring force of therubber member 39, so that the torque of the engine is not transmitted to theshaft 37. - A
crank chamber 43 is defined between thefront housing 32 and thecylinder block 36. In thecrank chamber 43, a rotor 44 is fixed on theshaft 37. Aswash plate 46 is coupled to the rotor 44 via ahinge mechanism 45. Thehinge mechanism 45 renders variable an inclination of theswash plate 46 relative to an axis of theshaft 37. Theswash plate 46 rotates together with the rotor 44. - A plurality of
pistons 47 engage with peripheral portions of theswash plate 46 via shoes, respectively. Thepistons 47 are received incorresponding cylinder bores 48 formed in thecylinder block 36 so as to be axially slidable. When theswash plate 46 rotates, each of thepistons 47 makes a reciprocating motion in the corresponding cylinder bore 48 with a stroke determined by an inclination of theswash plate 46. - The
cylinder head 34 is formed with asuction chamber 51 along its peripheral portion and with a discharge chamber 52 at the center thereof. Between thesuction chamber 51 and the discharge chamber 52 is connected a known refrigeration circuit. - The
valve plate assembly 33 is provided withsuction holes 53 anddischarge holes 54 for establishing communication of thecylinder bores 48 with thesuction chamber 51 and the discharge chamber 52, and with valve mechanisms for those holes. - When the
shaft 37 rotates, thepistons 47 make the reciprocating motion in thecylinder cores 48, respectively. Following the reciprocating motion of thepistons 47, refrigerant gas in the refrigeration circuit is sucked into the cylinder bores 48 from thesuction chamber 51 and discharged into the refrigeration circuit from the discharge chamber 52. - The compression displacement of the variable displacement compressor depends on the stroke of the
pistons 47 determined by the inclination of theswash plate 46. For controlling the inclination of theswash plate 46, adisplacement control valve 10 is further provided in acontrol valve chamber 55 formed in thecylinder head 34. - The
control valve chamber 55 communicates with thecrank chamber 43, thesuction chamber 51 and the discharge chamber 52 viapassages suction chamber 51 communicates with thecrank chamber 43 via anarrow passage 59. - Referring now to Figs. 2A and 2B in addition, the
displacement control valve 10 will be described. - The
displacement control valve 10 adjusts the pressure in thecrank chamber 43 so as to control the stroke of thepistons 47. Thedisplacement control valve 10 comprises avalve casing 11 and abellows 12 disposed in thevalve casing 11. The inside of thebellows 12 is under vacuum and provided with a spring. - The
displacement control valve 10 further comprises aguide 13 receiving a lower end (in the figures) of thebellows 12 and disposed in a cavity of thevalve casing 11 so as to be movable, aspring 14 for biasing theguide 13 upward (in the figures), an adjustingscrew 15 forming a part of thevalve casing 11 and adjusting the expansion/ contraction amount of thebellows 12, atransfer rod 16 engaging at its one end with an upper end (in the figures) of thebellows 12 and supported by thevalve casing 11 so as to be movable, avalve member 18 engaging with the other end of thetransfer rod 16 so as to open/close acommunication passage 17 between the discharge chamber 52 and thecrank chamber 43 depending on the expansion/contraction of thebellows 12, and an electromagnet assembly comprising anelectromagnetic coil 21 and acore 24 for generating an electromagnetic force urging thevalve member 18 in a valve closing direction via aplunger 19 and atransfer rod 20. A combination of theelectromagnetic coil 21, thecore 24, theplunger 19 and thetransfer rod 20 is referred to as an externally biasing mechanism. - The
communication passage 17 comprises aninlet portion 17a communicated with the discharge chamber 52 through thepassage 58, a plurality ofoutlet portions 17b communicated with thecrank chamber 43 through thepassage 56, and anintermediate portion 17c between theinlet portion 17a and theoutlet portions 17b. Theintermediate portion 17c is formed with avalve seat 17d radially extended. - The
valve member 18 has afirst surface 18a facing thevalve seat 17d and a second surface 18b facing arear chamber 25 provided as a recessed portion at the bottom of thecore 24. When thefirst surface 18a rests on thevalve seat 17d, thecommunication passage 17 is closed. When thefirst surface 18a is apart from thevalve seat 17d, thecommunication passage 17 is opened. The second surface 18b is arranged to receive the pressure of thecrank chamber 43 via therear chamber 25 and apressure introducing passage 22 which is made to thevalve casing 11. Crank chamber pressure receiving areas of the first surface and thesecond surfaces 18a and 18b are set equal to each other when thefirst surface 18a of thevalve member 18 rests on the valve seat. Further, acircumference surface 18c of thevalve member 18 is supported by thevalve casing 11 so as to be movable with a gap therebetween set to be minimum. - The
valve casing 11 has a plurality of lateral holes 11a. The adjustingscrew 15 has a throughhole 15a. Each of the lateral holes 11a and the throughhole 15a communicates the cavity of thevalve casing 11 with thesuction chamber 51 through thepassage 57 and thecontrol valve chamber 55. Therefore, the cavity of thevalve casing 11 is subjected to the pressure of thesuction chamber 51. - Referring now to Fig. 3 in addition, the description will be made as regards an operation of the
displacement control valve 10. - Since no electromagnetic force is generated in the state where the
electromagnetic coil 21 is not energized, there is no force urging thevalve member 18 in the valve closing direction in a pressure balanced state. Thus, although thebellows 12 is contracted when the pressure in thesuction chamber 51 is high, since thevalve member 18 is biased upward (in the figures) by means of thespring 14, thevalve member 18 is constantly opened. If the compressor is activated in this state, the gas in the discharge chamber 52 is constantly introduced into thecrank chamber 43 to increase a pressure differential between thecrank chamber 43 and thesuction chamber 51, so that the compressor is kept at the minimum displacement. - The biasing force of the
spring 14 is set to be small, for example, smaller than an electromagnetic force generated by a current value i0(A) supplied to theelectromagnetic coil 21. Thus, thevalve member 18 can be closed in a current region of i0(A) or greater. - Assuming that the compressor is activated in the state where the pressures are balanced under 6kg/cm2G and that the current amount supplied to the
electromagnetic coil 21 is adjusted to a current value i3(A) for controlling the pressure in thesuction chamber 51 to be 2kg/cm2G, since an electromagnetic force generated by theelectromagnetic coil 21 is greater than the biasing force of thespring 14, thevalve member 18 is closed. Thus, the pressure in thecrank chamber 43 is lowered to be equal to the pressure in thesuction chamber 51. Therefore, the compressor is kept at the maximum displacement, and the pressure in thesuction chamber 51 is gradually lowered. As the pressure in thesuction chamber 51 is lowered, thebellows 12 is expanded to cause a lower end (in the figures) of theguide 13 to abut the adjustingscrew 15, so that a function of thespring 14 is lost. At this time, the pressure in thecrank chamber 43 applied to thevalve member 18 is canceled at the sides of the first and thesecond surfaces 18a and 18b, and the pressure in the discharge chamber 52 does not work in an axial direction of thevalve member 18. Accordingly, thevalve member 18 is open/close controlled depending on the electromagnetic force and the pressure in thesuction chamber 51 applied to thebellows 12. Specifically, when the pressure in thesuction chamber 51 is lowered to 2kg/cm2G, thebellows 12 is expanded to move thevalve member 18 in a valve opening direction. Therefore, the gas in the discharge chamber 52 is introduced into thecrank chamber 43 to increase a pressure differential between thecrank chamber 43 and thesuction chamber 51, so that the discharge displacement is reduced. Following this, when the pressure in thesuction chamber 51 increases, thebellows 12 is contracted to move thevalve member 18 in the valve closing direction. Accordingly, the pressure in thecrank chamber 43 is lowered to reduce a pressure differential between thecrank chamber 43 and thesuction chamber 51, so that the discharge displacement increases. - In this fashion, the opening degree of the
valve member 18 is adjusted to converge the pressure in thesuction chamber 51 to a given value, so that the discharge displacement is controlled. Accordingly, as shown in Fig. 3, the pressure control point of thesuction chamber 51 is univocally determined by a value of current supplied to theelectromagnetic coil 21. If the current value is set to be zero in this state, thebellows 12 is expanded to cause thevalve member 18 to be fully open. Thus, since a pressure differential between thecrank chamber 43 and thesuction chamber 51 highly increases, the minimum displacement is realized. Even if this increases the pressure in thesuction chamber 51 up to greater than 3.5kg/cm2G in Fig. 3 to contract thebellows 12, since thevalve member 18 is urged upward (in the figures) by thespring 14 to be constantly opened, the compressor is kept at the minimum displacement. - Turning to Fig. 4, the description will be directed to a displacement control valve according to a second embodiment of the present invention. Similar parts are designated by like reference numerals. In the displacement control valve, the
pressure introducing passage 22 is made to penetrate thevalve member 18 in the upward and downward direction of the figure. - Turning to Fig. 5, the description will be directed to a displacement control valve according, to a third embodiment of the present invention. Similar parts are designated by like reference numerals. In the displacement control valve, the
valve member 18 is slidably fitted in theintermediate portion 17c of thecommunication passage 17. In the manner known in the art, theinlet portion 17a of thecommunication passage 17 is opened or closed in response to movement of thevalve member 18 in the upward and downward direction in the figure. - Turning to Fig. 6, the description will be directed to a displacement control valve according to a fourth embodiment of the present invention. Similar parts are designated by like reference numerals. Also in the displacement control valve, the
pressure introducing passage 22 is made to penetrate thevalve member 18 in the upward and down ward direction of the figure. - While the present invention has thus far been described in connection with a few embodiments thereof, it will readily be possible for those skilled in the art to put this invention into practice in various other manners. For example, the bellows may expands/contracts in response to a pressure in at least one of the suction chamber and the crank chamber.
Claims (7)
- A displacement control valve (10) for use in a variable displacement compressor comprising a suction chamber (51), a crank chamber (43), and a discharge chamber (52),
said displacement control valve (10) comprising:a valve casing (11) defining a communication passage (17) for communicating said discharge chamber (52) with said crank chamber (43) to conduct gas from said discharge chamber (52) to said crank chamber (43),a valve member (18) placed in said communication passage (17) and movable along said communication passage (17) in a predetermined direction for adjusting a substantial opening degree of said communication passage (17), andmoving means (12, 16, 19, 20, 21, 24) for moving said valve member (18) in said predetermined direction,said valve member having a first surface (18a) controlling the passage opening and a second surface (18b) facing a rear chamber (25) as a recessed portion at the bottom of a core (24)
pressure applying means (22) for applying gas pressure to said first and said second surfaces (18a, 18b) in common. - A displacement control valve as claimed in claim 1, wherein said communication passage (17) has said valve seat (17d) facing said valve member (18) in said predetermined direction, said communication passage (17) being closed when said valve member (18) rests on said valve seat (17d), said communication passage (17) being opened when said valve member (18) is apart from said valve seat (17d), said first and said second surfaces (18a, 18b) have pressure receiving areas which are substantially equal to each other for receiving said gas pressure when said valve member (18) rests on said valve seat (17d).
- A displacement control valve as claimed in claim 1 or 2, wherein said valve member (18) is fitted in said communication passage (17) to be slidable in said predetermined direction, said communication passage (17) being opened or closed in response to movement of said valve member (18) in said predetermined direction.
- A displacement control valve as claimed in anyone of claims 1-3, wherein said communication passage (17) has an inlet portion (17a) for communicating with said discharge chamber (52), an outlet portion (17b) for communicating with said crank chamber (43), and an intermediate portion (17c) therebetween, said valve member (18) being placed in said intermediate portion (17c) so as to direct said first surface (18a) towards said outlet portion (17b) of the communication passage (17) said pressure applying means (22) having a pressure introducing passage (22) which is connected to said outlet portion (17b) and is for applying gas pressure in said outlet portion (17b) to said second surface (18b).
- A displacement control valve as claimed in claim 4, wherein said pressure introducing passage (22) is made in said valve casing (11).
- A displacement control valve as claimed in claim 4, wherein said pressure introducing passage (22) is made in said valve member (18).
- A displacement control valve as claimed in anyone of claims 1-6, wherein said moving means comprises a pressure sensitive member (12) contained in said valve casing (11) for causing deformation thereof in response to a pressure in at least one of said suction chamber (51) and said crank chamber (43) to urge said valve member (18) in a valve opening direction, and an externally biasing mechanism (19, 20, 21) coupled to said valve casing (11) for generating a biasing force in response to an external signal to apply said biasing force to said valve member (18) in a valve closing direction, said pressure sensitive member (12) is movable in said predetermined direction, said displacement control valve (10) further comprising a spring (14) disposed between said pressure sensitive member (12) and said valve casing (11) for urging said pressure sensitive member (12) in said valve opening direction.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP271516/97 | 1997-10-03 | ||
JP27151697A JP3754193B2 (en) | 1997-10-03 | 1997-10-03 | Volume control valve for variable capacity compressor |
JP27151697 | 1997-10-03 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0907021A2 EP0907021A2 (en) | 1999-04-07 |
EP0907021A3 EP0907021A3 (en) | 1999-09-08 |
EP0907021B1 true EP0907021B1 (en) | 2002-02-06 |
Family
ID=17501165
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19980118560 Expired - Lifetime EP0907021B1 (en) | 1997-10-03 | 1998-10-01 | Displacement control valve for use in a variable displacement compressor |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0907021B1 (en) |
JP (1) | JP3754193B2 (en) |
DE (1) | DE69803732T2 (en) |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2000009033A (en) * | 1998-06-18 | 2000-01-11 | Sanden Corp | Volume control valve for variable displacement compressor |
JP4118414B2 (en) | 1998-10-29 | 2008-07-16 | サンデン株式会社 | Control circuit for capacity control valve of variable capacity compressor |
JP2000283029A (en) * | 1999-03-26 | 2000-10-10 | Sanden Corp | Capacity control valve and variable displacement compressor |
JP4118587B2 (en) | 2002-04-09 | 2008-07-16 | サンデン株式会社 | Variable capacity compressor |
JP4162419B2 (en) | 2002-04-09 | 2008-10-08 | サンデン株式会社 | Variable capacity compressor |
JP4695032B2 (en) | 2006-07-19 | 2011-06-08 | サンデン株式会社 | Volume control valve for variable capacity compressor |
JP4861900B2 (en) | 2007-02-09 | 2012-01-25 | サンデン株式会社 | Capacity control system for variable capacity compressor |
JP5270890B2 (en) | 2007-09-26 | 2013-08-21 | サンデン株式会社 | Capacity control system for variable capacity compressor |
JP5075682B2 (en) | 2008-03-05 | 2012-11-21 | サンデン株式会社 | Capacity control system for variable capacity compressor |
JP4930440B2 (en) * | 2008-04-09 | 2012-05-16 | 株式会社デンソー | Refrigeration cycle equipment |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2567947B2 (en) * | 1989-06-16 | 1996-12-25 | 株式会社豊田自動織機製作所 | Variable capacity compressor |
KR910004933A (en) * | 1989-08-09 | 1991-03-29 | 미다 가쓰시게 | Variable displacement swash plate compressor |
DE69200356T2 (en) * | 1991-01-28 | 1995-02-16 | Sanden Corp | Swash plate compressor with a device for changing the stroke. |
JP3178631B2 (en) * | 1993-01-11 | 2001-06-25 | 株式会社豊田自動織機製作所 | Control valve for variable displacement compressor |
JP3355002B2 (en) * | 1993-10-15 | 2002-12-09 | 株式会社豊田自動織機 | Control valve for variable displacement compressor |
JP3255008B2 (en) * | 1996-04-17 | 2002-02-12 | 株式会社豊田自動織機 | Variable displacement compressor and control method thereof |
JP3585150B2 (en) * | 1997-01-21 | 2004-11-04 | 株式会社豊田自動織機 | Control valve for variable displacement compressor |
-
1997
- 1997-10-03 JP JP27151697A patent/JP3754193B2/en not_active Expired - Fee Related
-
1998
- 1998-10-01 EP EP19980118560 patent/EP0907021B1/en not_active Expired - Lifetime
- 1998-10-01 DE DE1998603732 patent/DE69803732T2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
DE69803732T2 (en) | 2002-10-17 |
EP0907021A2 (en) | 1999-04-07 |
JPH11107929A (en) | 1999-04-20 |
JP3754193B2 (en) | 2006-03-08 |
EP0907021A3 (en) | 1999-09-08 |
DE69803732D1 (en) | 2002-03-21 |
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