Variable displacement compressor and swash place linkage connection

Abstract

A variable displacement compressor having means for regulating the minimum inclination angle of a swash plate, a spring urging the swash plate in the inclination angle-increasing direction, and a spring urging the swash plate in the inclination angle-decreasing direction. The swash plate inclination angle is a as the sum of the urging forces of both springs is zero, when the drive shaft is not rotated; and, when the drive shaft is rotated, its inclination angle is b at which the sum of moments MS, MF is zero. Moment MS of rotational motion is based on selling the product of inertia in the variable-angle direction of the swash plate to decrease the inclination angle of the swash plate from a. Moment MF is based on the combined urging force of both springs set so that the inclination angle b is positioned at a minimum angle at maximum rotational speed.

Claims

1. A variable displacement compressor comprising: a housing in which a discharge chamber, a suction chamber, a crank chamber and cylinder bores are defined, pistons inserted into said cylinder bores, a drive shaft supported rotatably in said housing, a rotor fixed synchronously rotatably to said drive shaft, a swash plate linked with said rotor via a linking means, the swash plate being configured to rotate synchronously with said rotor and being attached slidably to said drive shaft so that an inclination angle of the swash plate is changeable relative to an axis of said drive shaft, a minimum inclination angle regulating means for regulating a minimum inclination angle of said swash plate to approximately 0, when said inclination angle of said swash plate orthogonal to said axis of said drive shaft is defined as 0, an inclination angle increasing spring mounted on said drive shaft and configured to urge said swash plate in a direction of increasing said inclination angle from said minimum inclination angle, an inclination angle decreasing spring mounted on said drive shaft and configured to urge said swash plate in a direction of decreasing said inclination angle from a maximum inclination angle through said minimum inclination angle, a conversion mechanism disposed between said pistons and said swash plate for converting rotational motion of said swash plate into reciprocating movement of said pistons, a control valve for controlling a pressure in said crank chamber, which control valve changes said inclination angle of said swash plate by varying a pressure difference between said crank chamber and said suction chamber to adjust a stroke of said pistons, compresses a refrigerant sucked from said suction chamber into cylinder bores and discharges a compressed refrigerant into said discharge chamber, and a linking body of said drive shaft, wherein said rotor, said linking means and said swash plate are configured so that: in a case in which said drive shaft is not rotated, said inclination angle of said swash plate is positioned at a predetermined inclination angle a at which a sum of an urging force of said inclination angle decreasing spring and an urging force of said inclination angle increasing spring becomes zero; and in a case in which said drive shaft is rotated at a position of said predetermined inclination angle a with the inclination angle of said swash plate, a moment of rotational motion MS based on a setting of a product of inertia in a variable-angle direction of said swash plate, the moment of rotational motion MS being adjustable by setting of a shape, a mass and a center of gravity of said swash plate, acts in said inclination angle decreasing direction to decrease said inclination angle of said swash plate from said predetermined inclination angle a, and whereby a moment MF based on a combined force of said urging force of said inclination angle decreasing spring and said urging force of said inclination angle increasing spring acts in said inclination angle increasing direction, thereby said inclination angle of said swash plate being positioned autonomously at a predetermined inclination angle b at which a sum of said moment MS and said moment MF becomes zero, and said sum of said moment MS and said moment MF is set in said inclination angle increasing direction at said minimum inclination angle of approximately 0, wherein said urging force of said inclination angle increasing spring, said urging force of said inclination angle decreasing spring and said product of inertia in said variable-angle direction of said swash plate are such that said predetermined inclination angle b is positioned at a minimum angle in a range of inclination angle, such that, at a time of a maximum operational rotational speed of the swash plate, the angle b balanced by the moment MS due to the product of inertia and the moment MF based on the combined force of said urging force of said inclination angle decreasing spring and said urging force of said inclination angle increasing spring is set at the minimum inclination angle in a case in which compression operation is performed, and wherein said predetermined inclination angle b is approximately 10.5.

2. The variable displacement compressor according to claim 1, wherein said linking means is a link mechanism having a link arm for linking said rotor with said swash plate.

Description

BRIEF EXPLANATION OF THE DRAWINGS

(1) FIG. 1 is a vertical sectional view of a variable displacement compressor according to an embodiment of the present invention.

(2) FIG. 2 is a graph indicating a relationship between a combined force of an urging force of an inclination angle decreasing spring and an urging force of an inclination angle increasing spring and the inclination angle in the variable displacement compressor depicted in FIG. 1.

(3) FIG. 3 is a vertical sectional view of a linking body in the variable displacement compressor depicted in FIG. 1.

(4) FIG. 4 is a graph showing characteristics of a product of inertia in a variable-angle direction of a swash plate in the variable displacement compressor depicted in FIG. 1.

(5) FIG. 5 is a graph showing a relationship between a moment MF and a moment MS at the time when a linking body is rotated in the variable displacement compressor depicted in FIG. 1.

(6) FIG. 6 is a graph indicating a relationship between an inclination angle b of a swash plate and a rotational speed of a compressor at the time when a linking body is rotated in the variable displacement compressor depicted in FIG. 1.

(7) FIG. 7 is a concept diagram showing a state of compression operation at an angle near a minimum inclination angle of a swash plate in the variable displacement compressor depicted in FIG. 1.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

(8) Hereinafter, embodiments of the present invention will be explained with reference to the accompanying drawings.

(9) (1) Variable Displacement Compressor

(10) FIG. 1 depicts a variable displacement compressor according to an embodiment of the present invention used in an air conditioning system for vehicles. A variable displacement compressor 100 depicted in FIG. 1 is a clutchless compressor, and it has a cylinder block 101 having a plurality of cylinder bores 101a, a front housing 102 provided at one end of cylinder block 101, and a cylinder head 104 provided at the other end of cylinder block 101 via a valve plate 103.

(11) A drive shaft 110 is disposed across a crank chamber 140 defined by cylinder block 101 and front housing 102, and around a central portion in its axial direction, a swash plate 111 is disposed. Swash plate 111 is linked to a rotor 112 fixed to drive shaft 110 via a link mechanism 120, and the inclination angle thereof can be changed along drive shaft 110.

(12) Link mechanism 120 comprises a first arm 112a projected from rotor 112, a second arm 111a projected from swash plate 111, and a link arm 121 in which a side of one end is linked rotatably to first arm 112a via a first link pin 122 and a side of the other end is linked rotatably to second arm 111a via a second link pin 123.

(13) A through hole 111c of swash plate 111 is formed into such a shape that swash plate 111 can be inclined in a range from a maximum inclination angle (max) to a minimum inclination angle (min), and in through hole 111c, a maximum inclination angle regulating portion and a minimum inclination angle regulating portion each coming into contact with drive shaft 110 are formed.

(14) Where, in this embodiment, for example, a clutchless compressor having a maximum discharge capacity of approximately 160 cc is supposed, and when an inclination angle of the swash plate at the time at which swash plate 111 is orthogonal to drive shaft 110 is defined as 0, the minimum inclination angle regulating portion in through hole 111c is formed so that the inclination angle of swash plate 111 becomes approximately 0. Where, the minimum inclination angle min is approximately 0 means a region greater than 0.5 and smaller than 0.5, however, it is preferred that the region is set in a range from 0 or greater to smaller than 0.5. Further, the maximum inclination angle regulating portion in through hole 111c is formed so that the inclination angle of swash plate 111 is present in a range from 20 to 21.

(15) Between rotor 112 and swash plate 111, an inclination angle decreasing spring 114 comprising a compression coil spring for urging swash plate 111 down to the minimum inclination angle is attached, and between swash plate 111 and a spring support member 116, an inclination angle increasing spring 115 comprising a compression coil spring for urging swash plate 111 in a direction to increase the inclination angle of the swash plate 111 up to a predetermined inclination angle smaller than the maximum inclination angle is attached. Because the urging force of inclination angle increasing spring 115 at the minimum inclination angle is set greater than the urging force of the inclination angle decreasing spring 114, when drive shaft 110 is not rotated, swash plate 111 is positioned at a predetermined inclination angle a at which a combined force of the urging force of the inclination angle decreasing spring 114 and the urging force of the inclination angle increasing spring 115 becomes zero (FIG. 2).

(16) Where, a combined force Fmin of the urging forces at the minimum inclination angle min and the predetermined inclination angle a shown in FIG. 2 are set in consideration of smooth shift from an OFF state (an air conditioning system non-working state) of the clutchless compressor to an ON state (the air conditioning system working state) at a rotational speed of the compressor corresponding to that at an idling of a vehicle (for example, 700 rpm), and are set to be as small as possible in order to reduce power consumption in the OFF state. Because the predetermined inclination angle a must be in a region where the compression operation is performed securely, it is set in a region greater than 1 and smaller than 5 so as to avoid an excessive load of the compressor at the time of starting an engine. It is preferred that the predetermined inclination angle a is set in a range of 2 to 3, and that Fmin is set in a range of approximately 40N15N (the minus sign represents the inclination angle increasing direction). The combined force Fmax of the urging forces at the maximum inclination angle max is set in a range of approximately 60N15N.

(17) One end of drive shaft 110 extends up to the outside through the inside of a boss part 102a of front housing 102 projecting outside, and is connected to a power transmitting device which is not shown in the figure. Where, a shaft sealing device 130 is inserted between drive shaft 110 and boss part 102a, and it seals the inside from the outside. Drive shaft 110 and rotor 112 are supported by bearings 131, 132 in the radial direction and by a bearing 133 and a thrust plate 134 in the thrust direction. A power from an external drive source is transmitted to the power transmitting device, and drive shaft 110 can be rotated synchronously with a rotation of the power transmitting device. Where, a gap between a portion contacted with thrust plate 134 of drive shaft 110 and thrust plate 134 is adjusted to a predetermined gap by an adjusting screw 135.

(18) Each piston 136 is disposed in each cylinder bore 101a, the radially outer portion of swash plate 111 is contained in an internal space formed at one end of piston 136 projecting to a side of crank chamber 140, and swash plate 111 is configured to work in conjunction with piston 136 via a pair of shoes 137. Therefore, pistons 136 can be reciprocated in cylinder bores 101a in accordance with the rotation of swash plate 111.

(19) In cylinder head 104, defined are a suction chamber 141 at a central portion in the radial direction and a discharge chamber 142 annularly surrounding the radial outside of suction chamber 141. Suction chamber 141 communicates with cylinder bore 101a via a communication hole 103a formed on valve plate 103 and a suction valve (not shown in the figure), and discharge chamber 142 communicates with cylinder bore 101a via a discharge valve (not shown in the figure) and a communication hole 103b formed on valve plate 103.

(20) A compressor housing is formed by fastening front housing 102, cylinder block 101, valve plate 103 and cylinder head 104 with a plurality of through bolts 105 via gaskets which are not shown in the figure.

(21) A muffler is provided at an upper portion of cylinder block 101 in FIG. 1. The muffler is formed by fastening a lid member 106 to a formed wall 101b defined and formed in an upper portion of cylinder block 101 with bolts via a seal member which is not shown in the figure. A check valve 200 is disposed in a muffler space 143. Check valve 200 is disposed at a connecting portion between a communication path 144 and muffler space 143, works in response to a pressure difference between communication path 144 (an upstream side) and muffler space 143 (a downstream side), closes communication path 144 when the pressure difference is smaller than a predetermined value, and opens communication path 144 when the pressure difference is greater than the predetermined value. Thus, discharge chamber 142 is connected to a discharge side of a refrigeration cycle in the air conditioning system via a discharge path formed from communication path 144, check valve 200, muffler 143 and a discharge port 106a.

(22) A suction port 104a and a communication path 104b are formed in cylinder head 104, and suction chamber 141 is connected to a suction side of a refrigeration cycle in the air conditioning system via a suction path formed from communication path 104b and suction port 104a. The suction path extends linearly from the radial outside of cylinder head 104 across a part of discharge chamber 142.

(23) A control valve 300 is further provided in cylinder head 104. Control valve 300 adjusts an opening degree of a communication path 145 communicating between discharge chamber 142 and crank chamber 140, and controls an amount of discharged gas introduced into crank chamber 140. Further, the refrigerant in crank chamber 140 flows into suction chamber 141 through a communication path 101c, a space 146 and an orifice 103c formed on valve plate 103.

(24) Therefore, by changing the pressure in crank chamber 140 by control valve 300 to change the inclination angle of swash plate 111, namely, strokes of pistons 136, it is possible to variably control the displacement for discharge of variable displacement compressor 100.

(25) When the air conditioning system is operated, that is, in a state where variable displacement compressor 100 is operated, the amount of electricity applied to a solenoid incorporated in control valve 300 is adjusted based on an external signal, and the displacement for discharge of variable displacement compressor 100 is controlled variably so that the pressure in suction chamber 141 becomes a predetermined value. Control valve 300 can control the suction pressure in an optimum manner in accordance with an external environment.

(26) Further, when the air conditioning system is not operated, that is, in a state where variable displacement compressor 100 is not operated, communication path 145 is forcibly opened by turning off the supply of electricity to the solenoid incorporated in control valve 300, thereby controlling the displacement for discharge of variable displacement compressor 100 to a minimum.

(27) (2) Variable-Angle Moment that Acts on Swash Plate

(28) The variable-angle moment that acts on swash plate 111 at the time of operating the variable displacement compressor 100 is as follows. A moment MCL caused by the cylinder pressures acting on respective pistons (in the inclination angle increasing direction) A moment MCR caused by the pressure in the crank chamber acting on respective pistons (in the inclination angle decreasing direction) A moment MP caused by the inertial forces of reciprocal motions of pistons (in the inclination angle increasing direction) A moment MS of rotational movement based on the setting of the product of inertia in the variable-angle direction of the swash plate A moment MF caused by the combined force of the urging force of the inclination angle decreasing spring and the urging force of the inclination angle increasing spring

(29) When the air conditioning system is operated, the moments of gas pressure (MCR-MCL) are generally greater than the other mechanical moments (MP, MS, MF), therefore it is possible to give less consideration to the mechanical moments. However, because the moment MP and the moment MS are functions containing the square of the rotational speed, the moment MP and the moment MS cannot be ignored in the high-speed rotation region.

(30) In particular, because the moments of gas pressure (MCL, MCR) become quite small in an OFF state of the clutchless compressor (at the time when the air conditioning system is not operated), the variable-angle motion of swash plate 111 becomes easy to be affected the mechanical moments (MP, MS, MF).

(31) The moments, the values of which are adjustable, among the mechanical moments are the moment MF and the moment MS. The moment MF can be adjusted by the urging forces of inclination angle decreasing spring 114 and inclination angle increasing spring 115 and their spring constants, and, in this embodiment, it can be calculated from a product of the urging force F shown in FIG. 2 and a distance L between a momentary rotation center C at an arbitrary inclination angle of swash plate 111, which is defined depending upon its design as shown in FIG. 3, and the axial center of drive shaft 110 (MF=F.Math.L). Where, the momentary rotation center is an intersection between a line orthogonal to the axial line of drive shaft 110 through a rotational center (point K) of swash plate 111 and an axial line determined through a center of first link pin 122 and a center of second link pin 123 in a linking body 400 of drive shaft 110 on which inclination angle decreasing spring 114 and inclination angle increasing spring 115 are mounted, rotor 112, link mechanism 120 and swash plate 111 shown in FIG. 3.

(32) Further, the moment MS can be adjusted by the shape, the mass and the center of gravity of swash plate 111, that is, the setting of the product of inertia, and, in this embodiment, it can be calculated from the value of product of inertia P shown in FIG. 4 using an equation MS=P.Math.2 (where, is an angular speed of rotation of the drive shaft).

(33) FIG. 4 shows the product of inertia in the variable-angle direction of swash plate 111 including influences due to link pin 123 and link arm 121.

(34) Since second link pin 123 is press-fitted into swash plate 111, it is integrated with swash plate 111. Link arm 121 rotates around a center of first link pin 122 and changes in its position in correspondence with the change of inclination angle of swash plate 111. When drive shaft 111 is rotated, since a moment of rotational movement acts on a portion around the center of first link pin 122 by link arm 121, link arm 121 causes a moment of rotational movement by which swash plate 111 is directed toward the inclination angle increasing direction all the time via second link pin 123. Therefore, in consideration of the moment of rotational movement in the inclination angle increasing direction caused by link arm 121, the product of inertia of the linking body of second link pin 123 and swash plate 111 is set to exhibit such a property as shown in FIG. 4. Namely, because the value of product of inertia P is configured by two factors of link arm 121 and the linking body of second link pin 123 and swash plate 111, it exhibits a range of variation broader than that in other hinge structures having no link arm 121.

(35) Where, the inclination angle s of the swash plate at which the value of product of inertia P becomes zero is set in a range greater than 0 and smaller than 1.

(36) (3) Inclination Movement of Swash Plate by Moment MF and Moment MS

(37) Next, with reference to FIG. 5 and FIG. 6, it will be explained how the inclination angle of swash plate 111 is positioned by the moment MF and the moment MS at the time when linking body 400 of drive shaft 110 on which inclination angle decreasing spring 114 and inclination angle increasing spring 115 are mounted, rotor 112, link mechanism 120 and swash plate 111 is rotated.

(38) For example, a case is considered where variable displacement compressor 100 is operated at a condition where cylinder head 104, valve plate 103, discharge valve, suction valve and pistons 136 are removed from the compressor under atmospheric pressure. In this condition, only the moment MF and the moment MS act on the swash plate because the moment of gas pressure (MCR-MCL) and the moment MP become zero.

(39) Where, inclination angle of the swash plate can be determined, for example, by measuring a displacement of swash plate 111 in the axial direction using a laser displacement measuring device at the time when swash plate 111 is rotated. When the position of swash plate 111 at which the laser is irradiated is set at a position corresponding to a pitch circle through which the center axes of respective pistons 136 pass, the measured displacement L of swash plate 111 in the axial direction becomes the piston stroke itself. In this case, when the diameter of the pitch circle is represented by D, a relation between the inclination angle and the displacement L of the swash plate is represented by tan =L/D, and the inclination angle of swash plate 111 can be determined easily by measuring the displacement L of swash plate 111 in the axial direction.

(40) In a state where the rotation of drive shaft 110 is stopped, because a relation MS=0 is satisfied, the inclination angle of swash plate 111 is positioned at the inclination angle a of swash plate 111 at which the urging force of inclination angle decreasing spring 114 and the urging force of inclination angle increasing spring 115 are balanced.

(41) When drive shaft 110 is rotated from the state where the rotation is stopped up to a predetermined rotational speed, the moment MS of rotational movement based on the product of inertia P in the variable-angle direction of swash plate 111 acts on swash plate 111 to change the inclination angle of swash plate 111 from the inclination angle a. Where, because a relation s<a is satisfied, the moment MS acts in the inclination angle decreasing direction, and the inclination angle of swash plate 111 becomes smaller from the inclination angle a toward the inclination angle s.

(42) When the inclination angle of swash plate 111 becomes smaller than the inclination angle a, since the moment MF caused by the combined force F of the urging forces of springs shown in FIG. 2 acts on swash plate 111 in the inclination angle increasing direction, the inclination angle of swash plate 111 is positioned autonomously at a position where the sum of the moment MF and the moment MS becomes zero (an inclination angle b). The inclination angle b approaches to the inclination angle s as the rotational speed of drive shaft 110 increases, and becomes the smallest angle at the maximum rotational speed (Nmax). The inclination angle b(Nmax) at the maximum rotation speed is set at a minimum angle in a range of inclination angle where the compression operation is performed securely. Namely, at the maximum rotational speed, a requisite minimum compression operation is securely guaranteed, and the inclination angle of swash plate 111 is prevented from becoming unnecessarily great.

(43) Where, the maximum rotational speed (Nmax) is assumed to be approximately 9000 rpm (1000 rpm) in a swash plate type variable displacement compressor, for example.

(44) The mechanical minimum inclination angle min of swash plate 111 is set at approximately 0, although there is a possibility that the inclination angle transitionally reaches the minimum inclination angle min in the operating state of actual variable displacement compressor 100, because in this state the moment MP and the moment of gas pressure (MCR-MCL) are either zero or quite small, in order to return the displacement for discharge from the minimum inclination angle min, the inclination angle b(Nmax) must be positioned in a region of inclination angle where the compression operation is performed securely by the moment MF and the moment MS.

(45) Usually, when the inclination angle of swash plate 111 becomes small and approaches to approximately 0, the compression operation is performed insufficiently or is not performed at all under a condition where the inclination angle becomes smaller than a certain inclination angle. Accordingly, when this inclination angle becoming the boundary was determined experimentally, the boundary was recognized to be approximately 0.2, and it was confirmed that the inclination angle of swash plate 111 at which the compression operation was performed securely was 0.4 or greater.

(46) Namely, as shown in the concept diagram in FIG. 7 showing a state of compression operation at a position near the minimum inclination angle, when an inclination angle of a boundary between a region where the compression operation is not performed at all and a region where the compression operation is performed insufficiently is represented by c, and an inclination angle of the boundary between the region where the compression operation is performed insufficiently and a region where the compression operation is performed securely is represented by d, these regions can be represented as follows.

(47) The region where the compression operation is not performed at all: 0<c

(48) The region where the compression operation is performed insufficiently: c<d

(49) The region where the compression operation is performed securely: d

(50) It is confirmed that c is approximately 0.2 and d is 0.4 or greater. Whether the compression operation is performed or not is judged at a rotational speed of the compressor corresponding to an idling state of a vehicle (for example, 700 rpm).

(51) Therefore, it is desirable that the inclination angle s at which the value of product of inertia P becomes zero in FIG. 4 is approximately 0.4 (in a range of approximately 0.40.3), and that the above-described inclination angle b(Nmax) is approximately 1 (in a range of approximately 10.5), preferably 1 or less (where s<b).

(52) In link mechanism 120, although a fluctuation in the inclination angle b(Nmax) becomes great because a fluctuation of the value of product of inertia P is greater than those of other hinge structures, because there is also a fluctuation in the combined force F of the urging forces of the springs, and further because there are friction forces acting on link mechanism 120 and on a sliding portion between the periphery of drive shaft 110 and through hole 111c at the time when swash plate 111 is inclined, since the inclination angle b(Nmax) is recognized by actually rotating linking body 400, it is possible to securely position the inclination angle b within a desired range by correcting the value of product of inertia P and the combined force F of the urging forces of the springs so that the inclination angle b(Nmax) is set at a target inclination angle.

(53) As described above, since the urging force of inclination angle decreasing spring 114, the urging force of inclination angle increasing spring 115 and the product of inertia in the variable-angle direction of swash plate 111 are set so that, when drive shaft 110 is rotated with respect to linking body 400, the inclination angle of swash plate 111 decreases autonomously as the rotational speed increases, by the setting of the product of inertia in the variable-angle direction of swash plate 111, and at the maximum rotational speed, the inclination angle of the swash plate is positioned at a minimum angle in a range of inclination angle where the compression operation is performed securely, such a configuration can contribute efficiently to the reduction in power consumption of the variable displacement compressor in the high-speed rotation region. Further, at the same time, it can contribute to the improvement of lifetime of shaft sealing device 130 because the increase of the pressure in the crank chamber is suppressed.

(54) Where, the above-described value of s is shown as a value exhibiting a desired state and not limited thereto. For example, even if s is set at a slightly negative angle (for example, 0.5<s<0), the urging forces of the springs may be set so that a desired b can be obtained according to the sum of the moment MF and the moment MS.

(55) Further, although in the above-described embodiment variable displacement compressor 100 is described as a clutchless compressor, it may also be a variable displacement compressor provided with an electromagnetic clutch. Further, the present invention can be applied to a wobble plate type variable displacement compressor.

(56) Further, the linking means for linking the rotor and the swash plate is not limited to the above-described embodiment. For example, a structure may be employed wherein a slot is formed in a rotor arm, and a pin fixed to a swash plate is linked to the slot.

(57) Further, although the swash plate is supported directly by the drive shaft in the above-described embodiment, a swash plate structure may be employed wherein the swash plate is supported by a swash plate support member (sleeve) which is attached slidably to the drive shaft.

(58) Furthermore, the minimum inclination angle regulating means also is not limited to the above-described embodiment. For example, the minimum inclination angle may be regulated by fixing a snap ring to the drive shaft.

INDUSTRIAL APPLICABILITY

(59) The present invention can be applied to any swash plate type variable displacement compressor which compresses a refrigerant, and in particular, it is suitably applied to a compressor used in an air conditioning system for vehicles.

EXPLANATION OF SYMBOLS

(60) 100: variable displacement compressor 101: cylinder block 101a: cylinder bore 101b: formed wall 101c: communication path 102: front housing 102a: boss part 103: valve plate 103a: suction hole 103b: discharge hole 103c: orifice 104: cylinder head 104a: suction port 104b: communication path 105: through bolts 106: lid member 106a: discharge port 110: drive shaft 111: swash plate 111a: second arm 111c: through hole 112: rotor 112a: first arm 114: inclination angle decreasing spring 115: inclination angle increasing spring 116: spring support member 120: link mechanism 121: link arm 122: first link pin 123: second link pin 130: shaft sealing device 131, 132: radial bearing 133: thrust bearing 134: thrust plate 135: adjusting screw 136: piston 137: shoe 140: crank chamber 141: suction chamber 142: discharge chamber 143: muffler space 144: communication path 145: pressure supplying path 146: space 200: check valve 300: control valve