JP2007107538A - Variable displacement compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable displacement compressor capable of improving pressure control accuracy in a suction chamber and forcedly maintaining minimum displacement. <P>SOLUTION: In this variable displacement compressor, a displacement control valve is equipped with a valve system opening/closing an air supply passage by responding to the pressure of the suction chamber 65 and with a solenoid 12 applying electromagnetic force to the valve system and capable of changing suction chamber pressure control characteristics of the valve system. The valve system has a first pressure correction part reducing effects of the pressure of a discharge chamber 64 on the opening/closing direction of a valve element 5 and a second pressure correction part reducing effects of the pressure of a crank chamber 55 on the opening/closing direction of the valve element 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a variable capacity compressor used in an automotive air conditioner.

  Conventionally, variable capacity compressors have been used in refrigerant circuits of automotive air conditioners. A capacity control valve mechanism 100 as shown in the partial sectional view of FIG. 4 is provided so as to change the capacity of the cooling medium to be compressed by the variable capacity compressor.

  Referring to FIG. 4, the capacity control valve mechanism 100 is accommodated in the accommodating portion 53 a that accommodates the capacity control valve mechanism 100 provided on one end side of the rear housing 53. The capacity control valve mechanism 100 includes a valve casing 101 including a casing body 101a having a through hole 101c provided along the axial direction, and a cap-shaped lid member 101b attached to one end thereof. A bellows portion 102 as pressure-sensitive means is disposed in a pressure-sensitive space formed by a recess at one end of the casing body 101a of the valve casing 101 and the lid member 101b. In the bellows portion 102, shaft members 102d are provided at both ends of the bellows body 102c, the inside of the bellows body 101c is evacuated, and an internal spring 102a is disposed between the shaft members 102d therein. The space in which the bellows portion 102 is disposed communicates with the suction chamber 65 via a communication passage 67, and the bellows portion 102 disposed in the pressure-sensitive space is configured to receive pressure in the suction chamber 65. Has been. A support member 102b is provided at one end of the bellows portion 2 continuously to one end of the shaft member 102, and a spring 103 is provided around the support member 102b, and is configured to press the bellows main body 102c downward in the drawing. Has been.

  The transmission rod 104 is supported so that it can be inserted into a through hole 101c provided in the valve casing 101a, and one end of the transmission rod 104 is in contact with the support member 102b of the bellows portion 102. The other end side of the transmission rod 104 communicates with a recess on the other end side of the casing main body 101a, and a ball valve 105 is provided in contact therewith.

  The ball valve 105 moves in the axial direction in conjunction with the expansion and contraction of the bellows portion 102, and opens and closes the communication passage 101d between the discharge chamber 64 and the crank chamber 55 connected to one end of the through hole 101c.

  A valve chamber 106 communicating with the discharge chamber 64 through the communication hole 101e is formed at the other end of the valve casing main body 101a where the ball valve 105 is disposed. A stator 107 is provided at the other end (upper end in the figure) of the valve casing main body 101a, and a cup-shaped accommodation portion 108a is provided at one end at the upper end of the ball valve 105 in the figure. A solenoid rod 108 which is in contact with the stator 107 and supported so as to be inserted is provided. A plunger 109 is provided in contact with the upper part of the stator 107 through which the solenoid rod 108 is inserted, and a tube 110 is provided so as to cover the upper part of the stator 107 and the periphery of the plunger 109. In the tube 110, a plunger chamber 111 is formed on the upper portion of the stator 107. Further, a solenoid 112 as a magnetic field applying means is disposed so as to cover the periphery of the tube 110. The solenoid 112 applies an electromagnetic force to the gap between the plunger 109 and the stator 107 and applies the electromagnetic force to the ball valve 105 via the solenoid rod 108.

  Specifically, when the cooling load increases during cooling, the electromagnetic force increases and the force acts so that the opening degree of the ball valve 105 decreases. As the valve opening decreases, the amount of refrigerant flowing into the crank chamber decreases, the pressure in the crank chamber decreases, and the inclination of the swash plate (angle formed with respect to the plane perpendicular to the drive shaft) increases. On the other hand, when the cooling load is small, the electromagnetic force decreases, the force acts so as to increase the opening of the ball valve 105, the amount of refrigerant flowing into the crank chamber increases, and the pressure in the crank chamber increases. The inclination of the swash plate is reduced.

In the conventional capacity control valve mechanism 100 having such a configuration, the force Fv that presses the ball valve 105 in the valve closing direction and the bellows portion 102 and the transmission rod 104 act to open the ball valve 105 in the valve opening direction. The force Fb for pressing is expressed by the following equations 1 and 2.

Here, when Fv <Fb, the valve body composed of the ball valve 105 opens, but the following equation 3 is established from the above equations 1 and 2.

Here, when Pc = Ps + α is substituted into the above equation 3 and rearranged, the following equation 4 is established.

  The above equation 4 is the suction chamber pressure control characteristic of the capacity control valve mechanism 100, and the characteristic that the suction chamber pressure changes by changing the energization amount (I) to the electromagnetic coil comprising the solenoid 112 as shown in FIG. It has become. A variable capacity compressor employing a capacity control valve of this structure is called a so-called external control system, and the capacity can be freely changed by an external signal.

  However, in the conventional external control type variable capacity compressor, the acceleration state of the vehicle is detected and the compressor is forcibly maintained at the minimum capacity, thereby reducing the power consumption of the compressor and improving the acceleration performance of the vehicle. It has been proposed.

  In the conventional capacity control valve mechanism, even if the energization to the solenoid 112 is turned off, Fv = (Pd−Pc) · Sv> 0 from the above formula 1, and the pressure difference for closing the ball valve 105 is reduced. For example, if the suction chamber pressure exceeds the control upper limit, the bellows contracts and Fb <0 from the above equation (2), so that the valve body is closed and the discharge gas is supplied to the crank chamber. There was a problem that it could not be maintained at the minimum capacity.

  Further, as shown in the above formula 4, there is a problem that even if a constant current is applied to the electromagnetic coil 112, the suction chamber pressure changes due to the discharge chamber pressure, and stable control is impaired.

  Therefore, in order to reduce the influence of the discharge chamber pressure, it is necessary to reduce the seal area of the ball valve 105, which is a valve body. In this case, the amount of discharge gas supplied to the crank chamber 55 is insufficient, and capacity control is performed. There was a problem that became unstable.

  Therefore, a technical problem of the present invention is to provide a variable capacity compressor that can improve the suction chamber pressure control accuracy and can be forcibly maintained at a minimum capacity.

  According to the present invention, a plurality of cylinder bores in which a discharge chamber, a suction chamber, a crank chamber, and a piston are disposed are formed in a housing, and a drive shaft rotatably supported in the housing, and the drive shaft A conversion mechanism including a variable swash plate element for converting rotation into a reciprocating motion of the piston, a capacity control valve disposed in an air supply passage communicating the discharge chamber and the crank chamber, and the crank chamber and the suction chamber. A throttle element arranged in a continuous bleed passage, and by adjusting the opening of the capacity control valve, the crank chamber pressure is changed, the piston stroke is adjusted, and the refrigerant sucked into the cylinder bore is compressed and discharged. In a variable capacity compressor that discharges into a chamber, the capacity control valve has a valve mechanism that opens and closes an air supply passage in response to the suction chamber pressure, and an electromagnetic force that acts on the valve mechanism to control the suction chamber pressure control characteristics of the valve mechanism. Change The valve mechanism includes a first pressure correction unit that reduces the influence of the discharge chamber pressure that acts in the opening and closing direction of the valve body, and the influence of the crank chamber pressure that acts in the opening and closing direction of the valve body. A variable capacity compressor having a second pressure correction unit is obtained.

  One end side of the valve body is disposed in a valve chamber communicating with the discharge chamber, receives the crank chamber pressure opposite to the valve seat, and the other end side of the valve body defines the valve chamber and communicates with the suction chamber Facing the pressure chamber, and thereby the first pressure correction unit may be formed.

  The pressure receiving area on the other end side of the valve body may be set to be equal to or slightly larger than the area of the portion where the crank chamber pressure acts when one end side of the valve body abuts on the valve seat.

  The second pressure correction unit is in a region downstream of the valve body in the air supply passage, and one pressure receiving surface including a portion on which the crank chamber pressure acts when one end side of the valve body abuts against the valve seat You may have the other pressure receiving surface formed in the movable system member.

  Each of the area of the one pressure receiving surface and the area of the other pressure receiving surface may be set to be equal to the area of the portion where the crank chamber pressure acts when one end side of the valve body comes into contact with the valve seat. .

  The valve mechanism includes a pressure sensing member that receives suction chamber pressure and displaces the valve body in an opening and closing direction, and a transmission rod that transmits the displacement of the pressure sensing member to the valve body, and the other pressure receiving surface is It may be formed on the transmission rod.

  The solenoid may include a plunger, and the plunger chamber that houses the plunger may be in communication with the suction chamber.

  The plunger chamber may be configured to act as the pressure chamber.

  An opening means made of an elastic member may be provided for opening the air supply passage when the solenoid is demagnetized.

  According to the present invention, it is possible to provide a variable capacity compressor which can improve the suction chamber pressure control accuracy and can be forcibly maintained at a minimum capacity.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a variable displacement compressor using a variable displacement control valve according to an embodiment of the present invention. Referring to FIG. 1, a variable capacity compressor 50 includes a cylinder block 51 having a plurality of cylinder bores 51a, a front housing 52 provided at one end of the cylinder block 51, and a cylinder plate 51 via a valve plate device 54. And a rear housing 53 provided. A drive shaft 56 is provided across the crank chamber 55 defined by the cylinder block 51 and the front housing 52, and a swash plate 57 is disposed around the center thereof.

  The swash plate 57 is coupled to a rotor 58 fixed to the drive shaft 56 via a connecting portion 59.

  One end of the drive shaft 56 extends to the outside through the boss portion 52a protruding to the outside of the front housing 52, and an electromagnetic clutch 70 is provided around the boss portion 52a via a bearing 60. Yes.

  The electromagnetic clutch 70 includes a rotor 71 provided around the boss portion 52a, an electromagnet device 72 accommodated in the rotor, and a clutch plate 73 provided on one end surface of the rotor. One end of the drive shaft 56 is connected to the clutch plate 73 via a fixing member 74 such as a bolt.

  A seal member 52b is inserted between the drive shaft 56 and the boss portion 52a to block the inside from the outside. The other end of the drive shaft 56 is in the cylinder block 51, and the other end is supported by a support member 78. Reference numerals 75, 76, and 77 are bearings.

  A piston 62 is disposed in the cylinder bore 51 a, and the periphery of the outer peripheral portion of the swash plate 57 is accommodated in a recess 62 a at one end inside the piston 62, and the piston 62 and the inclined surface 57 are connected via the shoe 63. It has a structure that works together.

  The rear housing 53 is divided into a suction chamber 65 and a discharge chamber 64. The suction chamber 65 communicates with the cylinder bore 51a via a suction valve (not shown) provided in the valve plate device 54. The cylinder bore 51a communicates with a discharge valve provided in the valve plate device 54. The suction chamber 65 communicates with an air chamber 84 formed at one end of the drive shaft 56 through the opening 83.

  The capacity control valve mechanism 10 is provided in a recess in the rear wall of the rear housing 53.

  The above configuration has the same structure as that of the prior art except for the capacity control valve mechanism.

  FIG. 2 is a view showing a capacity control valve mechanism of the variable capacity compressor according to the first embodiment of the present invention. Referring to FIG. 2, the capacity control valve mechanism 10 is provided in a housing portion 53a of the control mechanism formed by recessing at one end in the rear housing 53 of the variable capacity compressor, as in the prior art. The capacity control valve mechanism 10 includes a valve casing 1 including a valve casing body 1a and a cap-shaped lid member 1b provided at one end thereof. A bellows portion 2 is disposed in a pressure-sensitive space at one end in the valve casing 1.

  The bellows portion 2 includes a bellows main body 2b, a shaft member 2d that protrudes from both ends of the bellows main body 2b and has a distal end spaced apart, and an internal spring disposed inside the bellows main body 2b around the shaft member 2d. 2a and a support member 2c provided continuously at one end of the shaft member 2d of the bellows body 2b, and the inside of the bellows body 2b is evacuated. A spring 3 is disposed around the support member 2c so as to press the bellows body 2b downward in the figure via the shaft member 2d.

  The bellows part 2 functions as a pressure-sensitive means for receiving the pressure of the suction chamber 65 (hereinafter referred to as suction chamber pressure).

  The casing main body 1a is provided with a through hole 1c penetrating in the axial direction. The through hole 1c is provided with a transmission rod 4 that is supported so that one end abuts on the upper end of the support member 2c of the bellows portion 2 and can be inserted into the valve casing body 1a. A large-diameter portion 5 a at one end of the valve body 5 is in contact with the other end of the transmission rod 4. The valve body 5 opens and closes the communication passages 66, 1 d, 1 e, 68 between the discharge chamber 64 and the crank chamber 55 according to the expansion and contraction of the bellows part 2. Around the valve body 5, there is disposed a stator 7 that is provided in contact with the upper end of the casing body 1a and supports the valve shaft 5b of the valve body 5 so that the valve shaft 5b can be inserted, and the casing body 1a and one end of the stator 7 Thus, the valve chamber 6 is formed. That is, one end of the valve body 5 is accommodated in the valve chamber 6.

  The valve chamber 6 communicates with the discharge chamber 64, the passage 68, the space 14, and the passage 1e. A plunger 9 is provided at the other end of the stator 7, and a tube 8 is provided so as to cover the plunger 9 including the stator 7. A plunger chamber 11 is defined by the stator 7 and the tube 8. A communication passage 13 is provided so that the plunger chamber 11 and the suction chamber 65 communicate with each other via the passage 67, the hole 1 f, and the pressure sensitive space 15.

  Solenoid 12 as a magnetic field applying means for applying an electromagnetic force to the gap between the plunger 9 and the stator 7 on the outer periphery of the tube 10 and applying the electromagnetic force to the large-diameter portion 5a of the valve body via the valve shaft 5b. The electromagnetic coil which consists of is arrange | positioned.

In the capacity control valve mechanism 100 having such a configuration, the force Fv that presses the valve body 5 in the valve closing direction and the force Fb that acts on the bellows portion 2 and the transmission rod 4 and presses the valve body 5 in the valve opening direction are respectively. The following equations 5 and 6 are shown.

Here, if Pc = Ps + α, the following equations 7 and 8 hold.

  Here, when the energization amount (I) to the electromagnetic coil composed of the solenoid 12 is zero, the electromagnetic force f (I) = 0, and Fv = (Sv−Sp) · (Pd−Ps) −1α · Sv. However, if Pd−Ps> 0, α = Pc−Ps> 0, and Sv ≦ Sp, Fv <0 is always established. That is, by setting the suction chamber pressure receiving area (Sp) of the valve shaft 5b to be equal to or larger than the seal area (Sv) of the valve body 5, the pressure in the suction chamber 65 exceeds the control upper limit and the bellows portion 2 Even if Fb <0, the amount of energization (I) to the electromagnetic coil 12 becomes zero, so that Fv <0 is always obtained, and the valve body is always pushed upward by the force of the pressure difference and opened. I speak. As a result, the discharge gas is always introduced into the crank chamber 55, and the minimum capacity can be maintained.

When Fv <Fb, the valve element opens, but the following equation 9 is established from equations 7 and 8.

  The above formula 9 is the suction pressure control characteristic of the capacity control valve mechanism according to the first embodiment.

  Therefore, if the suction chamber pressure receiving area (Sp) of the valve shaft 5b of the valve body is set slightly larger than the valve body seal area (Sv), the influence of the pressure in the discharge chamber (hereinafter referred to as the discharge chamber pressure) is small. A suction chamber pressure control characteristic is obtained.

In the above equation 9, if Sv = Sp, the suction chamber pressure control characteristic that is not affected by the discharge chamber pressure is obtained, and if Sv = Sr, α, that is, not affected by the pressure of the crank chamber, is given below. A suction chamber pressure control characteristic as shown in Equation 10 is obtained.

  FIG. 3 is a cross-sectional view showing a capacity control valve mechanism of a variable capacity compressor according to a second embodiment of the present invention. The capacity control valve mechanism 20 of the variable capacity compressor according to the second embodiment shown in FIG. 3 is different from the capacity control valve mechanism of the variable capacity compressor according to the first embodiment shown in FIG. 2 differs from FIG. 2 only in that a spring 3 'for pushing up the bellows part 2 in the valve opening direction is arranged in the cup part 1g recessed in the lower part of the lid member 1b. This spring 3 'has the purpose of supporting the bellows 2 particularly when the bellows portion 2 contracts, as in the prior art, but when the electromagnetic force f (I) becomes zero, the entire bellows portion 2 is There is a function of pushing up the valve body 5 to open the valve body 5 in the figure.

  In such a capacity control valve mechanism of the variable capacity compressor according to the embodiment of the present invention, when the energization amount to the solenoid is turned off, the valve body 5 is always opened due to the pressure difference acting in the opening / closing direction of the valve body. In addition, the minimum capacity can be maintained and the control accuracy of the suction chamber pressure is improved.

  Further, even in a configuration in which a spring is interposed between the bellows portion 2 and the valve casing 1a, when the energization amount to the solenoid is turned off, the valve body is always opened and the minimum capacity can be maintained.

It is sectional drawing which shows the whole structure of the variable capacity compressor using the capacity | capacitance variable control valve by the 1st Embodiment of this invention. It is sectional drawing which shows the capacity | capacitance control valve mechanism of the variable capacity compressor by the 1st Embodiment of this invention. It is sectional drawing which shows the capacity | capacitance control valve mechanism of the variable capacity compressor by the 2nd Embodiment of this invention. It is sectional drawing which shows the capacity | capacitance control valve mechanism of the variable capacity compressor by a prior art. It is a figure which shows the suction chamber pressure control characteristic of the capacity | capacitance control valve mechanism of the variable capacity compressor by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Valve casing 1a Casing main body 1b Cover member 1c Through-hole 1d, 1e, 66,68 Communication path 1f Hole 2 Bellow part 2a Internal spring 2b Bellows main body 2c Support member 2d Shaft member 3, 3 'Spring 4 Transmission rod 5 Valve body 5b Valve shaft 6 Valve chamber 7 Stator 8 Tube 9 Plunger 10 Volume control valve mechanism 11 Plunger chamber 12 Solenoid 13 Communication path 14 Space 15 Pressure sensitive space 50 Variable capacity compressor 51a Cylinder bore 51 Cylinder block 52 Front housing 52a Boss portion 53 Rear housing 53a Housing portion 55 Crank chamber 56 Drive shaft 57 Swash plate 58 Drive body 59 Connection portion 60 Bearing 61 Spring 62 Piston 62a Recess 63 Shoe 64 Discharge chamber 65 Suction chamber 66 Connection passage 67 Connection passage 70 Electromagnetic clutch 71 B 72 Electromagnetic device 73 Clutch plate 74 Fixing member 75, 76, 77 Bearing 81 Suction port 82 Discharge port 83 Opening 84 Air chamber 100 Capacity control valve mechanism 101a Casing body 101b Lid member 101c Through hole 101d, 101e Communication passage 101 Valve casing DESCRIPTION OF SYMBOLS 102 Bellow part 102a Internal spring 102b Support member 102c Bellows main body 102d Shaft member 103 Spring 104 Transmission rod 105 Ball valve 106 Valve chamber 107 Stator 108a Housing part 108 Solenoid rod 109 Plunger 110 Tube 111 Plunger chamber 112 Solenoid

Claims (9)

A plurality of cylinder bores in which a discharge chamber, a suction chamber, a crank chamber, and a piston are disposed are defined in the housing, and a drive shaft rotatably supported in the housing and the rotation of the drive shaft are reciprocated by the piston. A conversion mechanism including a swash plate element with variable tilt angle for conversion into motion, a capacity control valve disposed in an air supply passage communicating the discharge chamber and the crank chamber, and an extraction passage communicating the crank chamber and the suction chamber A variable capacity that changes the crank chamber pressure by adjusting the opening of the capacity control valve, compresses the piston stroke, compresses the refrigerant sucked from the suction chamber into the cylinder bore, and discharges it to the discharge chamber In the compressor,
The capacity control valve includes a valve mechanism that opens and closes the air supply passage in response to the suction chamber pressure, and a solenoid that allows an electromagnetic force to act on the valve mechanism and change a suction chamber pressure control characteristic of the valve mechanism,
The valve mechanism includes a first pressure correction unit that reduces the influence of the discharge chamber pressure that acts in the opening and closing direction of the valve body, and a second pressure correction unit that reduces the influence of the crank chamber pressure that acts in the opening and closing direction of the valve body. A variable capacity compressor characterized by comprising: The variable capacity compressor according to claim 1.
One end side of the valve body is disposed in a valve chamber communicating with the discharge chamber, receives the crank chamber pressure opposite to the valve seat, and the other end side of the valve body defines the valve chamber and communicates with the suction chamber A variable capacity compressor that faces the pressure chamber that forms the first pressure correction unit. In the variable capacity compressor according to claim 2,
The pressure receiving area on the other end side of the valve body is set to be equal to or slightly larger than the area of the portion on which the crank chamber pressure acts when one end side of the valve body abuts on the valve seat. A variable capacity compressor. The variable capacity compressor according to claim 3,
The second pressure correction unit is in a region downstream of the valve body in the air supply passage, and one pressure receiving surface including a portion on which the crank chamber pressure acts when one end side of the valve body abuts against the valve seat A variable capacity compressor having the other pressure receiving surface formed on the movable member. In the variable capacity compressor according to claim 4,
Each of the area of the one pressure receiving surface and the area of the other pressure receiving surface is set to be equal to the area of the portion where the crank chamber pressure acts when one end side of the valve body comes into contact with the valve seat. A variable capacity compressor characterized by In the variable capacity compressor according to claim 5,
The valve mechanism includes a pressure-sensitive member that receives suction chamber pressure and displaces the valve body in an opening and closing direction, and a transmission rod that transmits the displacement of the pressure-sensitive member to the valve body, and the other pressure-receiving surface is A variable capacity compressor formed on a transmission rod. In the variable capacity compressor according to any one of claims 1 to 6,
The solenoid includes a plunger, and a plunger chamber accommodating the plunger communicates with a suction chamber. The variable capacity compressor according to claim 7,
The variable capacity compressor, wherein the plunger chamber serves as the pressure chamber. In the variable capacity compressor according to any one of claims 1 to 8,
A variable capacity compressor comprising an opening means made of an elastic member for opening the air supply passage when the solenoid is demagnetized.

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