US20140234129A1 - Variable Capacity Compressor - Google Patents
Variable Capacity Compressor Download PDFInfo
- Publication number
- US20140234129A1 US20140234129A1 US14/346,909 US201214346909A US2014234129A1 US 20140234129 A1 US20140234129 A1 US 20140234129A1 US 201214346909 A US201214346909 A US 201214346909A US 2014234129 A1 US2014234129 A1 US 2014234129A1
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- US
- United States
- Prior art keywords
- swash plate
- inclination angle
- moment
- link arm
- drive shaft
- 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.)
- Abandoned
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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
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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
- F04B27/10—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 having stationary cylinders
- F04B27/1036—Component parts, details, e.g. sealings, lubrication
- F04B27/1054—Actuating elements
- F04B27/1072—Pivot mechanisms
Definitions
- the present invention relates to a variable capacity compressor for use in a vehicle air-conditioning system or the like.
- variable capacity compressor which variably controls a discharge capacity by changing the stroke amount of a piston rotating synchronously with a drive shaft and reciprocating with a variable inclination angle (angle of inclination) relative to the axis line of the drive shaft.
- variable capacity compressor In this type of variable capacity compressor, a moment in an inclination angle increasing direction acts on a swash plate due to a reciprocating inertia force of the piston. In order to counteract the moment, however, generally a product of inertia of the swash plate is set so that a moment of rotational motion in an inclination angle decreasing direction acts on the swash plate by the rotation of the swash plate.
- the product of inertia of the swash plate is sometimes set so that the moment of rotational motion in the inclination angle increasing direction acts on the swash plate by the rotation of the swash plate for a specific purpose.
- Patent Document 1 a large product of inertia of the swash plate is set at the minimum inclination angle 0° in order to use the inclination angle increasing moment caused by the rotational motion of the swash plate for capacity recovery in a positive manner.
- Patent Document 2 a relatively small product of inertia of the swash plate is set at the minimum inclination angle 0° in order to reduce the inclination angle increasing moment caused by the rotational motion of the swash plate so as to reduce power consumption during compressor off time.
- Patent Document 1 Japanese Laid-Open Patent Application Publication No. H07-293429
- Patent Document 2 Japanese Laid-Open Patent Application Publication No. 2000-2180
- the moment of rotational motion acting on the swash plate is able to be calculated by a formula such as, for example, one disclosed in Patent Document 1, with respect to the swash plate and a member that is fixed to the swash plate.
- the present invention has been made in view of the above conventional problem. Therefore, it is an object of the present invention to provide a variable capacity compressor in which a swash plate and a rotor are connected to each other via a link mechanism with both ends rotatably connected to the swash plate and the rotor, the variable capacity compressor capable of accurately calculating the total moment of rotational motion acting on the swash plate including an influence of a link arm and setting the total moment of rotational motion in an inclination angle increasing direction acting on the swash plate at the minimum inclination angle to a relatively small value.
- a variable capacity compressor which variably controls a discharge capacity of refrigerant by connecting a rotor fixed to a drive shaft rotatably supported within a housing to a swash plate slidably attached to the drive shaft so that an inclination angle relative to an axis line of the drive shaft is variable via a link arm with both ends rotatably connected to the rotor and the swash plate, allowing tilting of the swash plate while causing the swash plate to rotate synchronously with the rotor, converting the rotation of the swash plate to reciprocating motion parallel to the drive shaft of a piston inserted into a cylinder bore to draw and discharge the refrigerant, and controlling the inclination angle of the swash plate to control a stroke amount of the piston, having the following configuration.
- a shape, weight, and center of gravity of the swash plate, or those of the swash plate and a connected body integral therewith, are set so that a moment of rotational motion caused by the swash plate, or the swash plate and the connected body integral therewith, when the drive shaft rotates in the position of a minimum inclination angle ⁇ min of the swash plate acts in an inclination angle decreasing direction of the swash plate.
- a shape, weight, and center of gravity of the link arm, or those of the link arm and a connected body integral therewith, are set so that a total moment of rotational motion caused by the link arm, the swash plate, and the connected body integral therewith acts in an inclination angle increasing direction of the swash plate.
- the moment of rotational motion acting in the inclination angle increasing direction of the swash plate by setting the shape, weight, and center of gravity of the link arm, or those of the link arm and the connected body integral therewith, is determined by calculating a sum of moment components about the center of gravity and moment components caused by a centrifugal force acting on the center of gravity.
- a minimum inclination angle ⁇ min of the swash plate is set to 0° supposing that the inclination angle of the swash plate is 0° when the swash plate is orthogonal to the axis line of the drive shaft; and the moment of rotational motion caused by the link arm, the swash plate, and the connected body integral therewith acts in the inclination angle increasing direction of the swash plate in a range from the minimum inclination angle ⁇ min to a predetermined inclination angle ⁇ b and acts in the inclination angle decreasing direction of the swash plate in a range from an inclination angle just exceeding the predetermined inclination angle ⁇ b to a maximum inclination angle Amax; and the predetermined inclination angle ⁇ b is set to a minimum inclination angle range where a compression reaction force is applied when the piston compresses the refrigerant.
- the total moment of rotational motion in the inclination angle increasing direction acting on the swash plate at the minimum inclination angle of the swash plate is able to be set small and accurately, thereby improving the control accuracy of the inclination angle of the swash plate in the vicinity of the minimum inclination angle of the variable capacity compressor.
- the moment of rotational motion in the inclination angle increasing direction acting on the swash plate acts only on the minimum inclination angle region and the inclination angle smoothly increases when the inclination angle of the swash plate is less than ⁇ b, while sufficiently securing an inclination angle region ( ⁇ > ⁇ b) corresponding to a counter moment of a moment caused by an inertia force of a reciprocating motion of a piston or the like.
- FIG. 1 is a sectional view illustrating an internal structure of a variable capacity compressor according to the present invention.
- FIGS. 2A and 2B are a side view and a drawing of view A, respectively, of a link arm used in the variable capacity compressor.
- FIG. 3 is a perspective view of an assembly of a drive shaft and a rotor used in the variable capacity compressor.
- FIG. 4 is a perspective view of a swash plate used in the variable capacity compressor.
- FIG. 5 is a view illustrating a coordinate system used to calculate a moment of rotational motion with respect to an assembly of the drive shaft, the rotor, the swash plate, and the link arm used in the variable capacity compressor.
- FIG. 6 is a view illustrating a X′′Y′′Z′′ coordinate system of the link arm.
- FIG. 7 is a view used to calculate the center-of-gravity location G (G Y , G Z ) of the link arm.
- FIG. 8 is a diagram illustrating respective moments of rotational motion acting on the swash plate.
- FIG. 1 illustrates an internal structure of a variable capacity compressor according to the present invention.
- a variable capacity compressor 100 which is a clutchless compressor, includes a cylinder block 101 having a plurality of cylinder bores 101 a in a peripheral portion, a front housing 102 connected to one end of the cylinder block 101 , and a cylinder head 104 connected to the other end of the cylinder block 101 via a valve plate 103 .
- a drive shaft 110 is provided across a crank chamber 140 , which is defined by the cylinder block 101 and the front housing 102 , and a swash plate 111 is disposed around the axial center of the drive shaft 110 .
- the swash plate 111 is connected to a rotor 112 fixed to the drive shaft 110 via a link mechanism 120 and an inclination angle (the angle of inclination) relative to the axis line of the drive shaft 110 is variable.
- an inclination angle decreasing spring 114 which biases the swash plate 111 toward the minimum inclination angle up to the minimum inclination angle.
- an inclination angle increasing spring 115 which biases the swash plate 111 in a direction of increasing the inclination angle of the swash plate 111 .
- the biasing force of the inclination angle increasing spring 115 is set larger than the biasing force of the inclination angle decreasing spring 114 at the minimum inclination angle, by which the swash plate 111 is located at an inclination angle larger than the minimum inclination angle when the drive shaft 110 does not rotate and the biasing force of the inclination angle decreasing spring 114 is balanced with the biasing force of the inclination angle increasing spring 115 .
- One end of the drive shaft 110 passes through a boss portion 102 a projecting outward of the front housing 102 so as to extend to the outside thereof and is connected to a power transmission device, which is not illustrated.
- a shaft seal device 130 is inserted between the drive shaft 110 and the boss portion 102 a to block the inside from the outside.
- the drive shaft 110 and the rotor 112 are supported by bearings 131 and 132 in a radial direction and supported by a bearing 133 and a thrust plate 134 in a thrust direction.
- the power from an external drive source such as a vehicle engine is transmitted to the power transmission device, and the drive shaft 110 is rotatable in synchronization with the rotation of the power transmission device.
- a gap between an abutting portion of the drive shaft 110 abutting against the thrust plate 134 and the thrust plate 134 is adjusted to a predetermined gap by using an adjustment screw 135 .
- a piston 136 is disposed in a cylinder bore 101 a , an outer peripheral portion of the swash plate 111 is accommodated in a recess, which is formed in the inside of the end of the piston 136 projecting toward the crank chamber 140 , and the swash plate 111 works with the piston 136 via a pair of shoes 137 . Therefore, the rotation of the swash plate 111 enables the piston 136 to reciprocate within the cylinder bore 101 a.
- a suction chamber 141 and a discharge chamber 142 circularly enclosing the suction chamber 141 are divisionally formed in the center portion.
- the suction chamber 141 communicates with the cylinder bore 101 a via a communication hole 103 a and a suction valve (not illustrated) provided in the valve plate 103 .
- the discharge chamber 142 communicates with the cylinder bore 101 a via a discharge valve (not illustrated) and a communication hole 103 b which is formed in the valve plate 103 .
- a compressor housing is formed by fastening the front housing 102 , the cylinder block 101 , the valve plate 103 , and the cylinder head 104 via a gasket, which is not illustrated, by using a plurality of through bolts 105 .
- a muffler is provided in the upper part of the cylinder block 101 in the view.
- the muffler is formed by fastening a cover member 106 and a formed wall 101 b , which is divisionally formed in the upper part of the cylinder block 101 , via a seal member, which is not illustrated, by using bolts.
- a check valve 200 is disposed in a muffler space 143 .
- the check valve 200 is disposed in a connection between a communication passage 144 and the muffler space 143 .
- the check valve 200 operates in response to a pressure difference between the communication passage 144 (on the upstream side) and the muffler space 143 (on the downstream side): closes the communication passage 144 if the pressure difference is less than a predetermined value; and opens the communication passage 144 if the pressure difference is more than the predetermined value. Therefore, the discharge chamber 142 is connected to a discharge-side refrigerant circuit of the air-conditioning system via a discharge passage formed of the communication passage 144 , the check valve 200 , the muffler space 143 , and a discharge port 106 a.
- a suction port 104 a and a communication passage 104 b are formed, and the suction chamber 141 is connected to a suction-side refrigerant circuit of the air-conditioning system via a suction passage formed of the communication passage 104 b and the suction port 104 a .
- the suction passage extends in a straight line across a part of the discharge chamber 142 from the outside in the radial direction of the cylinder head 104 .
- the cylinder head 104 is further provided with a control valve 300 .
- the control valve 300 controls an introduction amount of discharge gas into the crank chamber 140 by adjusting the opening degree of a communication passage 145 , which communicates between the discharge chamber 142 and the crank chamber 140 .
- the refrigerant in the crank chamber 140 flows into the suction chamber 141 through a communication passage 101 c , a space 146 , and an orifice 103 c formed in the valve plate 103 .
- control valve 300 is able to variably control the discharge capacity of the variable capacity compressor 100 by varying the pressure of the crank chamber 140 , i.e., the back pressure of the piston 136 and changing the inclination angle of the swash plate 111 , i.e., the stroke amount of the piston 136 .
- the amount of current to a solenoid built in the control valve 300 is adjusted on the basis of an external signal, and the discharge capacity is variably controlled so that the pressure of the suction chamber 141 is at a predetermined value.
- the control valve 300 is able to optimally control the suction pressure according to an external environment.
- the communication passage 145 is forcibly opened by turning off the current to the solenoid built in the control valve 300 to control the discharge capacity of the variable capacity compressor 100 to the minimum.
- the rotor 112 is fixed to the drive shaft 110 and the rotor 112 is provided with a pair of first arms 112 a projecting toward the swash plate 111 side in parallel with the drive shaft 110 .
- One end 121 a which is formed substantially in a cylindrical shape, of the link arm 121 is guided into the inside of the pair of first arms 112 a.
- a first connecting pin 122 as a connecting means is inserted into a through hole 112 b formed in a first arm 112 a and into a through hole 121 b formed in one end 121 a of the link arm 121 , by which the link arm 121 is rotatable about the axis line of the first connecting pin 122 while being guided by the pair of first arms 112 a.
- first connecting pin 122 is press-fitted and retained in the through hole 121 b formed in the link arm 121 and a minute gap is formed between the outer periphery of the first connecting pin 122 and the through hole 112 b which is formed in the first arm 112 a , thereby enabling a relative rotation.
- the other end 121 c of the link arm 121 has a pair of arms projected from one end 121 a which is formed in a cylindrical shape, and a second arm 111 a which is projected from the swash plate 111 is guided into the inside of the arms.
- a second connecting pin 123 as a connecting means is inserted into the through hole 121 d formed at the other end 121 c of the link arm 121 and the through hole 111 b formed in the second arm 111 a , by which the link arm 121 is connected to the swash 111 , thus enabling the link arm 121 and the swash plate 111 to relatively rotate about the axis of the second connecting pin 123 .
- the second connecting pin 123 is press-fitted and retained in the through hole 111 b of the second arm 111 a and a minute gap is formed between the outer periphery of the second connecting pin 123 and the through hole 121 d which is formed in the link arm 121 , thereby enabling a relative rotation.
- the link mechanism 120 is composed of the first arm 112 a , the second arm 111 a , the link arm 121 , the first connecting pin 122 , and the second connecting pin 123 . Therefore, the swash plate 111 is connected to the rotor 112 fixed to the drive shaft 110 via the link mechanism 120 so as to receive a rotational torque of the rotor 112 , by which the inclination angle of the swash plate 111 is variable along the drive shaft 110 .
- a through hole 111 c of the swash plate 111 which is formed passing through the drive shaft 110 , is formed in a shape where the swash plate 111 is able to tilt within a range from the maximum inclination angle (Amax) to the minimum inclination angle ( ⁇ min).
- the through hole 111 c includes a maximum inclination angle restricting portion for restricting the maximum inclination angle by abutting against the drive shaft 110 and a minimum inclination angle restricting portion for restricting the minimum inclination angle in the same manner.
- the minimum inclination angle restricting portion of the through hole 111 c is formed so that the swash plate 111 is able to be displaced up to substantially 0° in the inclination angle.
- substantially 0° means a range of 0° ⁇ 0.5°.
- variable capacity compressor constructed as described above, the following describes a moment related to the inclination angle of the swash plate 111 .
- the moment is calculated as a moment of a connected body between the link arm 121 and the connecting portion such as the first connecting pin 122 .
- the connecting portion such as the second connecting pin for connecting the link arm 121 to the swash plate 111 is fixed to the link arm 121 side, the moment is calculated as a moment of a connected body between the link arm 121 and the connecting portion such as the second connecting pin 123 in the same manner.
- the first is an XYZ coordinate system with the axis of the drive shaft 110 as the Z axis in a plane including the axis of the drive shaft 110 and the center axis line of the piston 136 located at a top dead center position, a line passing through the center of the first connecting pin 122 and orthogonal to the axis of the drive shaft 110 as the Y axis, and a line passing through the intersection of the Z axis and the Y axis and orthogonal to the Z axis and the Y axis as the X axis.
- the second is an X′Y′Z′ coordinate system with the origin at the center of gravity G of the link arm 121 , having an X′ axis parallel to the X axis, a Y′ axis parallel to the Y axis, and a Z′ axis parallel to the Z axis.
- the link arm 121 has a symmetrical shape with respect to a plane including the axis of the drive shaft 110 and the center axis line of the piston 136 located at the top dead center position and also has a symmetrical shape with respect to a plane orthogonal to the above plane and passing through the center of the through hole 121 b (i.e., the first connecting pin 122 ) and the center of the through hole 121 d (i.e., the second connecting pin 123 ). Therefore, the center of gravity G is located in a YZ plane and on a line passing through the center of the first connecting pin 122 and the center of the second connecting pin 123 .
- the third is an X′′Y′′Z′′ coordinate system with the origin at the center of gravity G of the link arm and with a line passing through the center of the first connecting pin 122 and the center of the second connecting pin 123 as the Z′′ axis in a plane including the axis of the drive shaft 110 and the center axis line of the piston 136 located at the top dead center position, an axis orthogonal to the Z′′ axis as the Y′′ axis, and an axis line orthogonal to the Z′′ axis and the Y′′ axis as the X′′ axis.
- the link arm 121 rotates about the first connecting pin 122 in the YZ plane according to the displacing operation of the swash plate 111 and the position of the second connecting pin 123 changes accordingly.
- the angle of inclination ⁇ of the link arm 121 in the case of the inclination angle ⁇ of the swash plate 111 is an angle between the Y′′ axis and the Z′′ axis.
- the moment vector M L about the first connecting pin 122 is the time derivative of the angular momentum H L and therefore expressed by the following equation.
- the second term r ⁇ ma in the equation (1) is the cross product of a position vector and a force vector, which is a moment of force.
- the force ma is a centrifugal force applied to the center of gravity and r is a distance between the center of the second connecting pin and the center of gravity of the link arm in the Z-axis direction.
- the center-of-gravity location G (G Y , G Z ) of the link arm 121 is able to be determined as follows with reference to FIG. 7 .
- centrifugal force F C and the moment M FL about the first connecting pin 122 caused by the centrifugal force F C are able to be determined by the following equation.
- the moment M L of rotational motion caused by the link arm 121 about the first connecting pin 122 is able to be determined by the following equation from the equations (1), (5), and (6).
- the instant center of swash plate displacing R C is the intersection of a line passing through the center of rotation K of the swash plate 111 in the YZ plane and orthogonal to the Z axis and a line passing through the center of the first connecting pin 122 and the center of the second connecting pin 123 .
- the product of a force F R in the rotational direction of the second connecting pin 123 , which is generated by the moment M LX about the first connecting pin 122 , and a distance L R between the center of the second connecting pin and the instant center is a moment M RX about the instant center of swash plate displacing R C caused by the link arm 121 , and the moment M RX is able to be determined by the following equation.
- the swash plate 111 controls the discharge capacity by changing the inclination angle of the swash plate 111 by controlling the pressure of the crank chamber 140 acting on the piston 136 against the inclination angle increasing moment caused by a gas compression reaction force of the piston 136 by using the control valve 300 .
- the moments described below act on the change in the inclination angle of the swash plate 111 .
- the moments include a moment caused by a resultant force between a biasing force of the coil spring 114 and a biasing force of the coil spring 115 , a moment M P caused by an inertia force generated by reciprocating motion of the piston 136 or the like, and a moment M R of rotational motion acting on the swash plate 111 .
- the moment M P and the moment M R increase in proportion to the square of the rotational speed of the drive shaft 110 and therefore are almost negligible in a region in which the rotational speed is low, while affecting the change in the inclination angle of the swash plate 111 in a region of high rotational speed.
- the moment M P acts in the inclination angle increasing direction
- the moment M R is basically a counter moment of the moment M P , though the moment M R acts in the inclination angle increasing direction in a region of a small inclination angle.
- FIG. 8 illustrates the moments of rotational motion acting on the swash plate 111 at a predetermined rotational speed of the drive shaft.
- the second connecting pin 123 is press-fitted into the swash plate 111 , and the moment M S of the rotational motion generated by the rotation of the swash plate 111 on the basis of the setting of the product of inertia of the swash plate 111 includes that of the second connecting pin 123 .
- the shape, weight, and center of gravity of the swash plate 111 are set so as to have the characteristics illustrated by M S in FIG. 8 .
- the integral construction of the second connecting pin 123 and the swash plate 111 is set so as to cause a moment of rotational motion which orients the swash plate 111 in the inclination angle decreasing direction at the minimum inclination angle ⁇ min (0°) (M S ⁇ 0).
- the moment M S is calculated as a moment of the swash plate 111 only.
- the link arm 121 causes the moment of rotational motion acting about the first connecting pin 122 .
- the moment serves as a moment M RX of rotational motion which orients the swash plate 111 in the inclination angle increasing direction via the second connecting pin 123 (M RX >0).
- the shape, weight, and center of gravity of the link arm 121 are set so as to satisfy M S +M RX >0 at the minimum inclination angle ⁇ min (0°), here.
- the assembly where the link arm 121 is connected to the integral construction of the second connecting pin 123 and the swash plate 111 receives the moment of rotational motion which orients the swash plate 111 in the inclination angle increasing direction in a range from the minimum inclination angle ⁇ min (0°) to an inclination angle ⁇ b, while the assembly receives the moment of rotational motion which orients the swash plate 111 in the inclination angle decreasing direction in a range from an inclination angle just exceeding the inclination angle ⁇ b to the maximum inclination angle ( ⁇ max).
- the shape, weight, center of gravity of the link arm 121 are set so as to minimize the influence of M S +M RX as possible.
- the moment M S +M RX of the rotational motion which orients the swash plate 111 in the inclination angle increasing direction, contributes to increasing the inclination angle of the swash plate from the region of less than the inclination angle ⁇ b, but when the inclination angle reaches an inclination angle region where the compression reaction force is generated when the piston 136 compresses the gas, the moment M S +M RX is no longer needed. Therefore, the inclination angle ⁇ b is set to the minimum inclination angle region where the compression reaction force is generated when the piston 136 compresses the gas. Specifically, the inclination angle ⁇ b is set to an inclination angle region which causes the discharge capacity to be within a range of 2% to 5% where the maximum discharge capacity corresponding to the maximum inclination angle ⁇ max is 100%.
- the inclination angle of the swash plate 111 is less than ⁇ b, for example when the variable capacity compressor 100 is run in the non-operating state, switching the variable capacity compressor 100 from this state to the operating state causes the moment M S +M RX of rotational motion to assist the increase in the inclination angle of the swash plate caused by the biasing force of the coil spring 115 , by which the inclination angle of the swash plate is smoothly increased.
- the moment M S +M RX of rotational motion immediately serves as the counter moment of the moment M P caused by an inertia force to contribute to decreasing the moment imbalance.
- the moment of rotational motion in the inclination angle increasing direction acting on the swash plate acts only on a required minimum inclination angle region, thereby smoothly increasing the inclination angle in the case where the inclination angle of the swash plate is less than ⁇ b and sufficiently securing the inclination angle region ( ⁇ > ⁇ b) corresponding to the counter moment of the moment caused by an inertia force generated by reciprocating motion of the piston or the like.
- the moment M P +M S +M RX arising from the drive shaft rotation is able to be maintained at a value close to zero with these settings, thereby minimizing an influence on the discharge capacity control by the control of the pressure in the crank chamber 140 (back pressure of the piston 136 ) with the control valve 300 as possible and improving the control accuracy.
- Patent Document 2 in the case of preventing an increase of the inclination angle increasing moment caused by the rotational motion of the swash plate by setting a small product of inertia of the swash plate at the minimum inclination angle, the influence of the inclination angle increasing moment acting on the swash plate by the link arm is relatively large, which causes the inclination angle of the swash plate to deviate from the target in the case where the swash plate is located in the vicinity of the minimum inclination angle.
- the moment of rotational motion in the inclination angle increasing direction of the swash plate with the settings of the shape, weight, and center of gravity of the link arm is determined by calculating the sum of the moment components about the center of gravity of the link arm and the moment components caused by the centrifugal force acting on the center of gravity of the link arm, by which the moment of rotational motion is able to be accurately calculated.
- the link arm is a single member in the above embodiment, the link arm may include a plurality of members.
- the link arm is symmetrical in shape in the above embodiment, but may be asymmetrical in shape.
- the connecting means of the link arm is a pin in the above embodiment
- the link arm may have a structure without the use of a pin or pins.
- a structure where the tip of one end of the link arm is rotatably supported may be provided on the rotor side without using the first connecting pin.
- the swash plate is directly supported by the drive shaft in the above embodiment, the swash plate may be supported by a swash plate support (sleeve) slidably fitted to the drive shaft in an alternative swash plate structure.
- the minimum inclination angle restricting portion is formed in the through hole 111 c of the swash plate in the embodiment, but a circlip or the like may be attached to the drive shaft to restrict the minimum inclination angle.
- variable capacity compressor may be equipped with an electromagnetic clutch.
- present invention is also applicable to a variable capacity compressor driven by a motor.
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Abstract
Description
- The present invention relates to a variable capacity compressor for use in a vehicle air-conditioning system or the like.
- There is known a variable capacity compressor which variably controls a discharge capacity by changing the stroke amount of a piston rotating synchronously with a drive shaft and reciprocating with a variable inclination angle (angle of inclination) relative to the axis line of the drive shaft.
- In this type of variable capacity compressor, a moment in an inclination angle increasing direction acts on a swash plate due to a reciprocating inertia force of the piston. In order to counteract the moment, however, generally a product of inertia of the swash plate is set so that a moment of rotational motion in an inclination angle decreasing direction acts on the swash plate by the rotation of the swash plate.
- At the minimum inclination angle or in the vicinity of the minimum inclination angle of the swash plate, however, the product of inertia of the swash plate is sometimes set so that the moment of rotational motion in the inclination angle increasing direction acts on the swash plate by the rotation of the swash plate for a specific purpose.
- In
Patent Document 1, a large product of inertia of the swash plate is set at theminimum inclination angle 0° in order to use the inclination angle increasing moment caused by the rotational motion of the swash plate for capacity recovery in a positive manner. On the other hand, in Patent Document 2, a relatively small product of inertia of the swash plate is set at theminimum inclination angle 0° in order to reduce the inclination angle increasing moment caused by the rotational motion of the swash plate so as to reduce power consumption during compressor off time. - Patent Document 1: Japanese Laid-Open Patent Application Publication No. H07-293429
- Patent Document 2: Japanese Laid-Open Patent Application Publication No. 2000-2180
- During the rotation of the drive shaft, the moment of rotational motion acting on the swash plate is able to be calculated by a formula such as, for example, one disclosed in
Patent Document 1, with respect to the swash plate and a member that is fixed to the swash plate. - For a variable capacity compressor, however, having a structure in which a link arm is not fixed to the swash plate and rotates about a first connecting pin (pin 11) when the inclination angle of the swash plate changes, for example, as disclosed in Japanese Laid-Open Patent Application Publication No. 2002-188565, the formula disclosed in
Patent Document 1 is not enough to calculate the total moment of rotational motion acting on the swash plate including an influence of the link arm. Therefore, conventionally, for example, the total moment has been calculated in consideration of only an inclination angle increasing moment caused by a centrifugal force of the link arm, which thereby causes a gap between the calculated value and the actual value in the total moment of rotational motion acting on the swash plate during the rotation of the drive shaft. - The present invention has been made in view of the above conventional problem. Therefore, it is an object of the present invention to provide a variable capacity compressor in which a swash plate and a rotor are connected to each other via a link mechanism with both ends rotatably connected to the swash plate and the rotor, the variable capacity compressor capable of accurately calculating the total moment of rotational motion acting on the swash plate including an influence of a link arm and setting the total moment of rotational motion in an inclination angle increasing direction acting on the swash plate at the minimum inclination angle to a relatively small value.
- Therefore, according to
claim 1 of the present invention, there is provided a variable capacity compressor which variably controls a discharge capacity of refrigerant by connecting a rotor fixed to a drive shaft rotatably supported within a housing to a swash plate slidably attached to the drive shaft so that an inclination angle relative to an axis line of the drive shaft is variable via a link arm with both ends rotatably connected to the rotor and the swash plate, allowing tilting of the swash plate while causing the swash plate to rotate synchronously with the rotor, converting the rotation of the swash plate to reciprocating motion parallel to the drive shaft of a piston inserted into a cylinder bore to draw and discharge the refrigerant, and controlling the inclination angle of the swash plate to control a stroke amount of the piston, having the following configuration. - A shape, weight, and center of gravity of the swash plate, or those of the swash plate and a connected body integral therewith, are set so that a moment of rotational motion caused by the swash plate, or the swash plate and the connected body integral therewith, when the drive shaft rotates in the position of a minimum inclination angle θmin of the swash plate acts in an inclination angle decreasing direction of the swash plate.
- A shape, weight, and center of gravity of the link arm, or those of the link arm and a connected body integral therewith, are set so that a total moment of rotational motion caused by the link arm, the swash plate, and the connected body integral therewith acts in an inclination angle increasing direction of the swash plate.
- The moment of rotational motion acting in the inclination angle increasing direction of the swash plate by setting the shape, weight, and center of gravity of the link arm, or those of the link arm and the connected body integral therewith, is determined by calculating a sum of moment components about the center of gravity and moment components caused by a centrifugal force acting on the center of gravity.
- Moreover, the invention according to claim 2 has the following configuration: a minimum inclination angle θmin of the swash plate is set to 0° supposing that the inclination angle of the swash plate is 0° when the swash plate is orthogonal to the axis line of the drive shaft; and the moment of rotational motion caused by the link arm, the swash plate, and the connected body integral therewith acts in the inclination angle increasing direction of the swash plate in a range from the minimum inclination angle θmin to a predetermined inclination angle θb and acts in the inclination angle decreasing direction of the swash plate in a range from an inclination angle just exceeding the predetermined inclination angle θb to a maximum inclination angle Amax; and the predetermined inclination angle θb is set to a minimum inclination angle range where a compression reaction force is applied when the piston compresses the refrigerant.
- According to the invention of
claim 1, the total moment of rotational motion in the inclination angle increasing direction acting on the swash plate at the minimum inclination angle of the swash plate is able to be set small and accurately, thereby improving the control accuracy of the inclination angle of the swash plate in the vicinity of the minimum inclination angle of the variable capacity compressor. - According to the invention of claim 2, the moment of rotational motion in the inclination angle increasing direction acting on the swash plate acts only on the minimum inclination angle region and the inclination angle smoothly increases when the inclination angle of the swash plate is less than θb, while sufficiently securing an inclination angle region (θ>θb) corresponding to a counter moment of a moment caused by an inertia force of a reciprocating motion of a piston or the like.
-
FIG. 1 is a sectional view illustrating an internal structure of a variable capacity compressor according to the present invention. -
FIGS. 2A and 2B are a side view and a drawing of view A, respectively, of a link arm used in the variable capacity compressor. -
FIG. 3 is a perspective view of an assembly of a drive shaft and a rotor used in the variable capacity compressor. -
FIG. 4 is a perspective view of a swash plate used in the variable capacity compressor. -
FIG. 5 is a view illustrating a coordinate system used to calculate a moment of rotational motion with respect to an assembly of the drive shaft, the rotor, the swash plate, and the link arm used in the variable capacity compressor. -
FIG. 6 is a view illustrating a X″Y″Z″ coordinate system of the link arm. -
FIG. 7 is a view used to calculate the center-of-gravity location G (GY, GZ) of the link arm. -
FIG. 8 is a diagram illustrating respective moments of rotational motion acting on the swash plate. - Hereinafter, an embodiment of the present invention will be described with reference to drawings.
FIG. 1 illustrates an internal structure of a variable capacity compressor according to the present invention. - A
variable capacity compressor 100, which is a clutchless compressor, includes acylinder block 101 having a plurality ofcylinder bores 101 a in a peripheral portion, afront housing 102 connected to one end of thecylinder block 101, and acylinder head 104 connected to the other end of thecylinder block 101 via avalve plate 103. - A
drive shaft 110 is provided across acrank chamber 140, which is defined by thecylinder block 101 and thefront housing 102, and aswash plate 111 is disposed around the axial center of thedrive shaft 110. Theswash plate 111 is connected to arotor 112 fixed to thedrive shaft 110 via alink mechanism 120 and an inclination angle (the angle of inclination) relative to the axis line of thedrive shaft 110 is variable. - Between the
rotor 112 and theswash plate 111, there is mounted an inclinationangle decreasing spring 114 which biases theswash plate 111 toward the minimum inclination angle up to the minimum inclination angle. On the opposite side of theswash plate 111, there is mounted an inclinationangle increasing spring 115 which biases theswash plate 111 in a direction of increasing the inclination angle of theswash plate 111. The biasing force of the inclinationangle increasing spring 115 is set larger than the biasing force of the inclinationangle decreasing spring 114 at the minimum inclination angle, by which theswash plate 111 is located at an inclination angle larger than the minimum inclination angle when thedrive shaft 110 does not rotate and the biasing force of the inclinationangle decreasing spring 114 is balanced with the biasing force of the inclinationangle increasing spring 115. - One end of the
drive shaft 110 passes through aboss portion 102 a projecting outward of thefront housing 102 so as to extend to the outside thereof and is connected to a power transmission device, which is not illustrated. In addition, ashaft seal device 130 is inserted between thedrive shaft 110 and theboss portion 102 a to block the inside from the outside. - The
drive shaft 110 and therotor 112 are supported bybearings bearing 133 and athrust plate 134 in a thrust direction. - Then, the power from an external drive source such as a vehicle engine is transmitted to the power transmission device, and the
drive shaft 110 is rotatable in synchronization with the rotation of the power transmission device. Incidentally, a gap between an abutting portion of thedrive shaft 110 abutting against thethrust plate 134 and thethrust plate 134 is adjusted to a predetermined gap by using anadjustment screw 135. - A
piston 136 is disposed in acylinder bore 101 a, an outer peripheral portion of theswash plate 111 is accommodated in a recess, which is formed in the inside of the end of thepiston 136 projecting toward thecrank chamber 140, and theswash plate 111 works with thepiston 136 via a pair ofshoes 137. Therefore, the rotation of theswash plate 111 enables thepiston 136 to reciprocate within thecylinder bore 101 a. - In the
cylinder head 104, asuction chamber 141 and adischarge chamber 142 circularly enclosing thesuction chamber 141 are divisionally formed in the center portion. Thesuction chamber 141 communicates with thecylinder bore 101 a via acommunication hole 103 a and a suction valve (not illustrated) provided in thevalve plate 103. Thedischarge chamber 142 communicates with thecylinder bore 101 a via a discharge valve (not illustrated) and acommunication hole 103 b which is formed in thevalve plate 103. - A compressor housing is formed by fastening the
front housing 102, thecylinder block 101, thevalve plate 103, and thecylinder head 104 via a gasket, which is not illustrated, by using a plurality of throughbolts 105. - Moreover, a muffler is provided in the upper part of the
cylinder block 101 in the view. The muffler is formed by fastening acover member 106 and a formedwall 101 b, which is divisionally formed in the upper part of thecylinder block 101, via a seal member, which is not illustrated, by using bolts. Acheck valve 200 is disposed in amuffler space 143. Thecheck valve 200 is disposed in a connection between acommunication passage 144 and themuffler space 143. Thecheck valve 200 operates in response to a pressure difference between the communication passage 144 (on the upstream side) and the muffler space 143 (on the downstream side): closes thecommunication passage 144 if the pressure difference is less than a predetermined value; and opens thecommunication passage 144 if the pressure difference is more than the predetermined value. Therefore, thedischarge chamber 142 is connected to a discharge-side refrigerant circuit of the air-conditioning system via a discharge passage formed of thecommunication passage 144, thecheck valve 200, themuffler space 143, and adischarge port 106 a. - In the
cylinder head 104, asuction port 104 a and acommunication passage 104 b are formed, and thesuction chamber 141 is connected to a suction-side refrigerant circuit of the air-conditioning system via a suction passage formed of thecommunication passage 104 b and thesuction port 104 a. The suction passage extends in a straight line across a part of thedischarge chamber 142 from the outside in the radial direction of thecylinder head 104. - The
cylinder head 104 is further provided with acontrol valve 300. Thecontrol valve 300 controls an introduction amount of discharge gas into thecrank chamber 140 by adjusting the opening degree of acommunication passage 145, which communicates between thedischarge chamber 142 and thecrank chamber 140. Moreover, the refrigerant in thecrank chamber 140 flows into thesuction chamber 141 through acommunication passage 101 c, aspace 146, and anorifice 103 c formed in thevalve plate 103. - Accordingly, the
control valve 300 is able to variably control the discharge capacity of thevariable capacity compressor 100 by varying the pressure of thecrank chamber 140, i.e., the back pressure of thepiston 136 and changing the inclination angle of theswash plate 111, i.e., the stroke amount of thepiston 136. - During air conditioning operation, i.e., in the operating state of the
variable capacity compressor 100, the amount of current to a solenoid built in thecontrol valve 300 is adjusted on the basis of an external signal, and the discharge capacity is variably controlled so that the pressure of thesuction chamber 141 is at a predetermined value. Thecontrol valve 300 is able to optimally control the suction pressure according to an external environment. - During non-air conditioning operation, i.e., in the non-operating state of the
variable capacity compressor 100, thecommunication passage 145 is forcibly opened by turning off the current to the solenoid built in thecontrol valve 300 to control the discharge capacity of thevariable capacity compressor 100 to the minimum. - Subsequently, the
link mechanism 120 according to the present invention will be described. - The
rotor 112 is fixed to thedrive shaft 110 and therotor 112 is provided with a pair offirst arms 112 a projecting toward theswash plate 111 side in parallel with thedrive shaft 110. Oneend 121 a, which is formed substantially in a cylindrical shape, of thelink arm 121 is guided into the inside of the pair offirst arms 112 a. - Specifically, a first connecting
pin 122 as a connecting means is inserted into a throughhole 112 b formed in afirst arm 112 a and into a throughhole 121 b formed in oneend 121 a of thelink arm 121, by which thelink arm 121 is rotatable about the axis line of the first connectingpin 122 while being guided by the pair offirst arms 112 a. - In addition, the first connecting
pin 122 is press-fitted and retained in the throughhole 121 b formed in thelink arm 121 and a minute gap is formed between the outer periphery of the first connectingpin 122 and the throughhole 112 b which is formed in thefirst arm 112 a, thereby enabling a relative rotation. - The
other end 121 c of thelink arm 121 has a pair of arms projected from oneend 121 a which is formed in a cylindrical shape, and asecond arm 111 a which is projected from theswash plate 111 is guided into the inside of the arms. A second connectingpin 123 as a connecting means is inserted into the throughhole 121 d formed at theother end 121 c of thelink arm 121 and the throughhole 111 b formed in thesecond arm 111 a, by which thelink arm 121 is connected to theswash 111, thus enabling thelink arm 121 and theswash plate 111 to relatively rotate about the axis of the second connectingpin 123. - In addition, the second connecting
pin 123 is press-fitted and retained in the throughhole 111 b of thesecond arm 111 a and a minute gap is formed between the outer periphery of the second connectingpin 123 and the throughhole 121 d which is formed in thelink arm 121, thereby enabling a relative rotation. - The
link mechanism 120 is composed of thefirst arm 112 a, thesecond arm 111 a, thelink arm 121, the first connectingpin 122, and the second connectingpin 123. Therefore, theswash plate 111 is connected to therotor 112 fixed to thedrive shaft 110 via thelink mechanism 120 so as to receive a rotational torque of therotor 112, by which the inclination angle of theswash plate 111 is variable along thedrive shaft 110. - A through
hole 111 c of theswash plate 111, which is formed passing through thedrive shaft 110, is formed in a shape where theswash plate 111 is able to tilt within a range from the maximum inclination angle (Amax) to the minimum inclination angle (θmin). Specifically, the throughhole 111 c includes a maximum inclination angle restricting portion for restricting the maximum inclination angle by abutting against thedrive shaft 110 and a minimum inclination angle restricting portion for restricting the minimum inclination angle in the same manner. - Supposing that the inclination angle of the swash plate is set to 0° when the
swash plate 111 is orthogonal to thedrive shaft 110, the minimum inclination angle restricting portion of the throughhole 111 c is formed so that theswash plate 111 is able to be displaced up to substantially 0° in the inclination angle. In addition, the term, “substantially 0°” means a range of 0°±0.5°. - Regarding the variable capacity compressor constructed as described above, the following describes a moment related to the inclination angle of the
swash plate 111. - First, the calculation of the moment of rotational motion caused by the link arm acting on the
swash plate 111 will be described with reference toFIGS. 5 to 7 . - When the connecting portion such as the first connecting
pin 122 for connecting thelink arm 121 to the rotor is fixed to thelink arm 121 side, the moment is calculated as a moment of a connected body between thelink arm 121 and the connecting portion such as the first connectingpin 122. Moreover, also when the connecting portion such as the second connecting pin for connecting thelink arm 121 to theswash plate 111 is fixed to thelink arm 121 side, the moment is calculated as a moment of a connected body between thelink arm 121 and the connecting portion such as the second connectingpin 123 in the same manner. - a. Coordinate System
- In an assembly of the
drive shaft 110, therotor 112, theswash plate 111, and thelink mechanism 120 of thevariable capacity compressor 100, three coordinate systems (XYZ, X′Y′Z′, X″Y″Z″) will be discussed as illustrated inFIGS. 5 and 6 . - The first is an XYZ coordinate system with the axis of the
drive shaft 110 as the Z axis in a plane including the axis of thedrive shaft 110 and the center axis line of thepiston 136 located at a top dead center position, a line passing through the center of the first connectingpin 122 and orthogonal to the axis of thedrive shaft 110 as the Y axis, and a line passing through the intersection of the Z axis and the Y axis and orthogonal to the Z axis and the Y axis as the X axis. - The second is an X′Y′Z′ coordinate system with the origin at the center of gravity G of the
link arm 121, having an X′ axis parallel to the X axis, a Y′ axis parallel to the Y axis, and a Z′ axis parallel to the Z axis. In addition, thelink arm 121 has a symmetrical shape with respect to a plane including the axis of thedrive shaft 110 and the center axis line of thepiston 136 located at the top dead center position and also has a symmetrical shape with respect to a plane orthogonal to the above plane and passing through the center of the throughhole 121 b (i.e., the first connecting pin 122) and the center of the throughhole 121 d (i.e., the second connecting pin 123). Therefore, the center of gravity G is located in a YZ plane and on a line passing through the center of the first connectingpin 122 and the center of the second connectingpin 123. - The third is an X″Y″Z″ coordinate system with the origin at the center of gravity G of the link arm and with a line passing through the center of the first connecting
pin 122 and the center of the second connectingpin 123 as the Z″ axis in a plane including the axis of thedrive shaft 110 and the center axis line of thepiston 136 located at the top dead center position, an axis orthogonal to the Z″ axis as the Y″ axis, and an axis line orthogonal to the Z″ axis and the Y″ axis as the X″ axis. - The
link arm 121 rotates about the first connectingpin 122 in the YZ plane according to the displacing operation of theswash plate 111 and the position of the second connectingpin 123 changes accordingly. The angle of inclination β of thelink arm 121 in the case of the inclination angle θ of theswash plate 111 is an angle between the Y″ axis and the Z″ axis. - b. Moment about Center of Gravity G of Link Arm
- When the
rotor 112 rotates, a moment of rotational motion acts about the first connectingpin 122 connected to therotor 112 by thelink arm 121. - The moment vector ML about the first connecting
pin 122 is the time derivative of the angular momentum HL and therefore expressed by the following equation. -
[Math. 1] -
M L ={dot over (H)} L ={dot over (H)} GL +r×ma (1) - where:
- {dot over (H)}GF: Moment vector about center of gravity of link arm
- r: Position vector of center of gravity of link arm relative to center of first connecting pin
- m: Weight of link arm
- a: Acceleration vector of center of gravity of link arm
- Since the
link arm 121 is symmetrical as described above, the principal axis of inertia coincides with the X″Y″Z″ axis. Therefore, the moment of inertia tensor IL is expressed by the following equation. -
- If the equation (2) is coordinate-transformed to that in the X′Y′Z′ coordinate system, the moment of inertia tensor IL′ is expressed by the following equation.
-
[Math. 3] -
(L ′=RI L R −1 (3) - R: Rotation matrix
Therefore, the angular momentum vector HGL about the center of gravity G is determined by the following equation. -
-
- ωz: Rotational angular velocity of drive shaft
- Therefore, the moment MGL about the center of gravity is obtained by the following equation.
-
- c. Moment Caused by Centrifugal Force Acting on Center of Gravity of Link Arm
- The second term r×ma in the equation (1) is the cross product of a position vector and a force vector, which is a moment of force.
- Since the
link arm 121 rotates about the first connectingpin 122 in the YZ plane, the moment vector is oriented in the X-axis direction. - Therefore, the force ma is a centrifugal force applied to the center of gravity and r is a distance between the center of the second connecting pin and the center of gravity of the link arm in the Z-axis direction.
- The center-of-gravity location G (GY, GZ) of the
link arm 121 is able to be determined as follows with reference toFIG. 7 . -
G Y =L Y +L G cos β -
G Z =L G sin β [Math. 6] - Therefore, the centrifugal force FC and the moment MFL about the first connecting
pin 122 caused by the centrifugal force FC are able to be determined by the following equation. -
[Math. 7] -
F C =mG YωZ 2 =m(L Y +L G cos β)ωZ 2 -
M FL =r×ma=−F C G Z =−mL G sin β(L Y +L G cos β)ωZ 2 (6) - d. Moment of Rotational Motion Caused by Link Arm about First Connecting Pin
- The moment ML of rotational motion caused by the
link arm 121 about the first connectingpin 122 is able to be determined by the following equation from the equations (1), (5), and (6). -
- e. Moment of Link Arm about Instant Center of Swash Plate Displacing
- The instant center of swash plate displacing RC is the intersection of a line passing through the center of rotation K of the
swash plate 111 in the YZ plane and orthogonal to the Z axis and a line passing through the center of the first connectingpin 122 and the center of the second connectingpin 123. - The product of a force FR in the rotational direction of the second connecting
pin 123, which is generated by the moment MLX about the first connectingpin 122, and a distance LR between the center of the second connecting pin and the instant center is a moment MRX about the instant center of swash plate displacing RC caused by thelink arm 121, and the moment MRX is able to be determined by the following equation. -
- LP: Distance between center of first connecting pin and center of second connecting pin
- Moment of Changing Inclination Angle of Swash Plate (
FIG. 8 ) - As described above, the
swash plate 111 controls the discharge capacity by changing the inclination angle of theswash plate 111 by controlling the pressure of thecrank chamber 140 acting on thepiston 136 against the inclination angle increasing moment caused by a gas compression reaction force of thepiston 136 by using thecontrol valve 300. The moments described below act on the change in the inclination angle of theswash plate 111. Specifically, the moments include a moment caused by a resultant force between a biasing force of thecoil spring 114 and a biasing force of thecoil spring 115, a moment MP caused by an inertia force generated by reciprocating motion of thepiston 136 or the like, and a moment MR of rotational motion acting on theswash plate 111. - Incidentally, the moment MP and the moment MR increase in proportion to the square of the rotational speed of the
drive shaft 110 and therefore are almost negligible in a region in which the rotational speed is low, while affecting the change in the inclination angle of theswash plate 111 in a region of high rotational speed. - The moment MP acts in the inclination angle increasing direction, while the moment MR is basically a counter moment of the moment MP, though the moment MR acts in the inclination angle increasing direction in a region of a small inclination angle.
-
FIG. 8 illustrates the moments of rotational motion acting on theswash plate 111 at a predetermined rotational speed of the drive shaft. - The second connecting
pin 123 is press-fitted into theswash plate 111, and the moment MS of the rotational motion generated by the rotation of theswash plate 111 on the basis of the setting of the product of inertia of theswash plate 111 includes that of the second connectingpin 123. Thus, the shape, weight, and center of gravity of theswash plate 111 are set so as to have the characteristics illustrated by MS inFIG. 8 . Specifically, the integral construction of the second connectingpin 123 and theswash plate 111 is set so as to cause a moment of rotational motion which orients theswash plate 111 in the inclination angle decreasing direction at the minimum inclination angle θmin (0°) (MS<0). - In addition, if the connecting member such as the second connecting pin or the like is secured to the
link arm 121, the moment MS is calculated as a moment of theswash plate 111 only. - When the
rotor 112 rotates, thelink arm 121 causes the moment of rotational motion acting about the first connectingpin 122. As illustrated inFIG. 8 , the moment serves as a moment MRX of rotational motion which orients theswash plate 111 in the inclination angle increasing direction via the second connecting pin 123 (MRX>0). - Therefore, the moment MR of rotational motion acting on the
swash plate 111 is calculated by MS+MRX. - The shape, weight, and center of gravity of the
link arm 121 are set so as to satisfy MS+MRX>0 at the minimum inclination angle θmin (0°), here. - Thus, the assembly where the
link arm 121 is connected to the integral construction of the second connectingpin 123 and theswash plate 111 receives the moment of rotational motion which orients theswash plate 111 in the inclination angle increasing direction in a range from the minimum inclination angle θmin (0°) to an inclination angle θb, while the assembly receives the moment of rotational motion which orients theswash plate 111 in the inclination angle decreasing direction in a range from an inclination angle just exceeding the inclination angle θb to the maximum inclination angle (θmax). - Although being set so as to satisfy MS+MRX>0, the shape, weight, center of gravity of the
link arm 121 are set so as to minimize the influence of MS+MRX as possible. - The moment MS+MRX of the rotational motion, which orients the
swash plate 111 in the inclination angle increasing direction, contributes to increasing the inclination angle of the swash plate from the region of less than the inclination angle θb, but when the inclination angle reaches an inclination angle region where the compression reaction force is generated when thepiston 136 compresses the gas, the moment MS+MRX is no longer needed. Therefore, the inclination angle θb is set to the minimum inclination angle region where the compression reaction force is generated when thepiston 136 compresses the gas. Specifically, the inclination angle θb is set to an inclination angle region which causes the discharge capacity to be within a range of 2% to 5% where the maximum discharge capacity corresponding to the maximum inclination angle θmax is 100%. - Accordingly, if the inclination angle of the
swash plate 111 is less than θb, for example when thevariable capacity compressor 100 is run in the non-operating state, switching thevariable capacity compressor 100 from this state to the operating state causes the moment MS+MRX of rotational motion to assist the increase in the inclination angle of the swash plate caused by the biasing force of thecoil spring 115, by which the inclination angle of the swash plate is smoothly increased. In addition, if the inclination angle of theswash plate 111 exceeds θb, the moment MS+MRX of rotational motion immediately serves as the counter moment of the moment MP caused by an inertia force to contribute to decreasing the moment imbalance. - Since the moment of rotational motion in the inclination angle increasing direction acting on the
swash plate 111 is limited to the range of 2% to 5% in the discharge capacity, an adverse effect caused by the moment of rotational motion in the inclination angle increasing direction can be substantially avoided even in the case where thevariable capacity compressor 100 rotates at high speed. - In this manner, the moment of rotational motion in the inclination angle increasing direction acting on the swash plate acts only on a required minimum inclination angle region, thereby smoothly increasing the inclination angle in the case where the inclination angle of the swash plate is less than θb and sufficiently securing the inclination angle region (θ>θb) corresponding to the counter moment of the moment caused by an inertia force generated by reciprocating motion of the piston or the like.
- The above configuration is achieved, as described in the aforementioned moment calculation process, by making settings so that the
link arm 121 causes the moment MLX of rotational motion acting about the first connectingpin 122 and the moment MLX serves as the moment MR (substantially constant regardless of a change in the inclination angle as illustrated inFIG. 8 ) in the inclination angle increasing direction of theswash plate 111 to act via the connection between thelink arm 121 and theswash plate 111, while the moment MS of rotational motion is set so as to act in the inclination angle decreasing direction of theswash plate 111, where the moment MS of rotational motion is caused by theswash plate 111 and the second connectingpin 123 when thedrive shaft 110 rotates in the position of the minimum inclination angle θmin of theswash plate 111. - Moreover, the moment MP+MS+MRX arising from the drive shaft rotation is able to be maintained at a value close to zero with these settings, thereby minimizing an influence on the discharge capacity control by the control of the pressure in the crank chamber 140 (back pressure of the piston 136) with the
control valve 300 as possible and improving the control accuracy. - If calculation is made in consideration of only the inclination angle increasing moment caused by the centrifugal force of the link arm in a simple manner in the variable capacity compressor including the link mechanism to be the target of the present invention, the total moment of rotational motion when the drive shaft rotates cannot be accurately calculated. Particularly, as disclosed in Patent Document 2, in the case of preventing an increase of the inclination angle increasing moment caused by the rotational motion of the swash plate by setting a small product of inertia of the swash plate at the minimum inclination angle, the influence of the inclination angle increasing moment acting on the swash plate by the link arm is relatively large, which causes the inclination angle of the swash plate to deviate from the target in the case where the swash plate is located in the vicinity of the minimum inclination angle.
- In this respect, in the above embodiment, the moment of rotational motion in the inclination angle increasing direction of the swash plate with the settings of the shape, weight, and center of gravity of the link arm is determined by calculating the sum of the moment components about the center of gravity of the link arm and the moment components caused by the centrifugal force acting on the center of gravity of the link arm, by which the moment of rotational motion is able to be accurately calculated.
- This enables accurate settings of the inclination angle of the swash plate in the vicinity of the minimum inclination angle, thereby enabling high-accuracy control of the discharge capacity of refrigerant represented by the control characteristic of the inclination angle, i.e., the stroke amount of the piston.
- Although the link arm is a single member in the above embodiment, the link arm may include a plurality of members.
- Moreover, the link arm is symmetrical in shape in the above embodiment, but may be asymmetrical in shape.
- Furthermore, although the connecting means of the link arm is a pin in the above embodiment, the link arm may have a structure without the use of a pin or pins. For example, a structure where the tip of one end of the link arm is rotatably supported may be provided on the rotor side without using the first connecting pin.
- Furthermore, although the swash plate is directly supported by the drive shaft in the above embodiment, the swash plate may be supported by a swash plate support (sleeve) slidably fitted to the drive shaft in an alternative swash plate structure.
- Moreover, the minimum inclination angle restricting portion is formed in the through
hole 111 c of the swash plate in the embodiment, but a circlip or the like may be attached to the drive shaft to restrict the minimum inclination angle. - Although the clutchless compressor is used in the embodiment, the variable capacity compressor may be equipped with an electromagnetic clutch. Moreover, the present invention is also applicable to a variable capacity compressor driven by a motor.
-
- 100: Variable capacity compressor
- 101: Cylinder block
- 101 a: Cylinder bore
- 102: Front housing
- 104: Cylinder head
- 110: Drive shaft
- 111: Swash plate
- 111 a: Second arm
- 111 c: Through hole
- 112: Rotor
- 112 a: First arm
- 114: Inclination angle decreasing spring
- 115: Inclination angle increasing spring
- 116: Spring support member
- 116 a: Cylindrical portion
- 120: Link mechanism
- 121: Link arm
- 122: First connecting pin
- 123: Second connecting pin
- 136: Piston
- 140: Crank chamber
- 141: Suction chamber
- 142: Discharge chamber
- 145: Communication passage
- 300: Control valve
- MP: Moment caused by inertia force generated by reciprocating motion of
piston 136 or the like - MRX: Moment of rotational motion acting on
swash plate 111 bylink arm 121 - MS: Moment of rotational motion acting on
swash plate 111 and second connectingpin 123
Claims (2)
Applications Claiming Priority (3)
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JP2011207633A JP5579144B2 (en) | 2011-09-22 | 2011-09-22 | Variable capacity compressor |
JP2011-207633 | 2011-09-22 | ||
PCT/JP2012/070667 WO2013042492A1 (en) | 2011-09-22 | 2012-08-14 | Variable capacity compressor |
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US20140234129A1 true US20140234129A1 (en) | 2014-08-21 |
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ID=47914271
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US14/346,909 Abandoned US20140234129A1 (en) | 2011-09-22 | 2012-08-14 | Variable Capacity Compressor |
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US (1) | US20140234129A1 (en) |
JP (1) | JP5579144B2 (en) |
CN (1) | CN103814215A (en) |
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WO (1) | WO2013042492A1 (en) |
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JP3417652B2 (en) * | 1994-04-21 | 2003-06-16 | 株式会社豊田自動織機 | Variable capacity swash plate compressor |
JP2005293429A (en) * | 2004-04-02 | 2005-10-20 | A Un:Kk | Animation producing device, and animation production method |
JP4976731B2 (en) * | 2006-04-07 | 2012-07-18 | カルソニックカンセイ株式会社 | Variable capacity compressor |
JP2008064057A (en) * | 2006-09-08 | 2008-03-21 | Calsonic Kansei Corp | Variable displacement compressor |
JP2009138630A (en) * | 2007-12-06 | 2009-06-25 | Calsonic Kansei Corp | Variable displacement compressor |
JP2009180135A (en) * | 2008-01-30 | 2009-08-13 | Calsonic Kansei Corp | Swash plate compressor |
-
2011
- 2011-09-22 JP JP2011207633A patent/JP5579144B2/en active Active
-
2012
- 2012-08-14 US US14/346,909 patent/US20140234129A1/en not_active Abandoned
- 2012-08-14 WO PCT/JP2012/070667 patent/WO2013042492A1/en active Application Filing
- 2012-08-14 DE DE112012003955.6T patent/DE112012003955T5/en not_active Withdrawn
- 2012-08-14 CN CN201280046162.8A patent/CN103814215A/en active Pending
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5304042A (en) * | 1992-04-10 | 1994-04-19 | Kabushiki Kaisha Toyoda Jidoshokki Seisakusho | Variable displacement compressor |
US6283722B1 (en) * | 1999-04-02 | 2001-09-04 | Kabushiki Kaisha Toyoda Jidoshokki Seisakusho | Variable displacement type compressor |
Also Published As
Publication number | Publication date |
---|---|
JP2013068171A (en) | 2013-04-18 |
DE112012003955T5 (en) | 2014-07-03 |
JP5579144B2 (en) | 2014-08-27 |
WO2013042492A1 (en) | 2013-03-28 |
CN103814215A (en) | 2014-05-21 |
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