JP2009264110A - Compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable displacement compressor which reserves a suitable amount of lubricating oil in a swash plate chamber, with respect to all discharge capacities, at all times. <P>SOLUTION: An oil storage chamber 44 and the swash plate chamber 20 communicate with each other through an oil return passage, the oil return passage is constituted of a communication passage 46 that allows the oil storage chamber 44 to communicate with a cylinder bore 25 and an oil-introducing groove 47, formed in the peripheral surface of a piston 26 and allows the communication passage 46 to communicate with the swash plate chamber 20; and as the discharge capacity is increased, the distance through the oil return passage, from the oil storage chamber 44 to the swash plate chamber 20, is lengthened. Accordingly, by a simple processing, the amount of oil returned is reduced following an increase in discharge capacity, and the amount of lubricating oil fed to the swash plate chamber 20, regardless of the discharge capacity, including the amount of lubricating oil mixed in blowby gas from a compression chamber 27, is substantially held fixed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a compressor used in a vehicle air conditioner, and more particularly to a variable capacity swash plate compressor.

  In the variable displacement swash plate type compressor, when the swash plate rotates as the drive shaft is driven, the swinging motion according to the tilt angle of the swash plate is converted into the reciprocating motion of the piston through the shoe. Reciprocates within. As a result, the refrigerant gas is sucked into the cylinder bore from the suction chamber, and the refrigerant gas is compressed and discharged to the discharge chamber. The refrigerant gas thus discharged into the discharge chamber is circulated to the external refrigeration circuit. The compression capacity of the refrigerant gas discharged to the discharge chamber is controlled by adjusting the pressure in the swash plate chamber by the control valve. The discharge chamber and the swash plate chamber communicate with each other through an air supply passage, and the suction chamber and the swash plate chamber communicate with each other through an extraction passage. In the compressor, the refrigerant gas in the discharge chamber is supplied as a control gas to the swash plate chamber via the supply passage, and the refrigerant gas in the swash plate chamber is discharged as a control gas to the suction chamber via the extraction passage. Thus, the pressure in the swash plate chamber is regulated. By this pressure adjustment, the inclination angle of the swash plate is adjusted, the stroke amount of the piston is adjusted, and the discharge capacity of the compressor is adjusted. A control valve is provided on the air supply passage, and the amount of refrigerant gas supplied to the swash plate chamber is adjusted by adjusting the opening of the control valve.

  Mainly, in these compressors, during the suction, compression, and discharge strokes, lubrication of the swash plate or the like that slides in the swash plate chamber is performed by the lubricating oil stored in the swash plate chamber. Prevents seizure.

  However, in each of the compressors described above, the lubricating oil stored in the swash plate chamber also flows out to the suction chamber through an extraction passage that communicates the swash plate chamber and the suction chamber. Lubricating oil that has flowed out to the suction chamber flows into the bore due to the reciprocating motion of the piston and is returned to the swash plate chamber together with the blow-by gas. Will be circulated.

  The flow of such lubricating oil into the refrigeration circuit is such that if the n compressor is of a variable capacity type, the refrigerant circulation amount in the refrigeration circuit is large during large capacity operation or when the drive shaft is rotating at high speed, Mist lubricating oil together with the refrigerant is replenished in a large amount into the swash plate chamber by blow-by gas or the like, so this is not a problem, but during small capacity operation or when the drive shaft is rotating at low speed, The amount of lubricant circulating in the swash plate chamber is less than the amount of circulated coolant and the amount of mist-like lubricant that is replenished in the swash plate chamber. End up. In this case, the swash plate or the like may not be sufficiently lubricated, resulting in poor sliding.

  On the other hand, if it is designed to secure a sufficient oil reservoir amount in the swash plate chamber during small capacity operation, the lubricating oil will be excessively stored during large capacity operation. In this case, the stored oil is heated by stirring by the rotation of the swash plate, the temperature of the variable capacity compressor is increased, and various seal members formed of sliding parts in the compressor, rubber material, or resin material There is a risk of lowering the durability.

Therefore, in a conventional variable displacement swash plate compressor, an attempt has been made to suitably lubricate the swash plate chamber according to all operating conditions.
For example, in the compressor disclosed in Patent Document 1, an oil reservoir chamber that collects separated oil separated in an oil separation chamber in the machine, and a swash plate chamber that returns the stored oil in the oil reservoir chamber includes a return oil passage. The opening of the return oil passage is reduced when the pressure in the oil separation chamber is high (large capacity operation), and the opening of the return oil passage is reduced when the pressure is low (small capacity operation). Valve means are provided which are controlled to increase the degree.
JP-A-6-249146

  However, in the compressor disclosed in Patent Document 1, the amount of return oil is controlled not by the discharge capacity but by the oil separation chamber and thus the pressure in the discharge chamber. It is hard to say that it has been.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a variable displacement compressor in which a suitable amount of lubricating oil is always stored in the swash plate chamber for every discharge capacity. Is to provide.

  In order to achieve the above object, in the compressor of the present invention, a swash plate accommodated in a swash plate chamber is connected to a drive shaft so as to be able to rotate integrally and change an inclination angle, and a swash plate has an outer periphery via a shoe. The piston is moored, and the piston is reciprocated linearly in the cylinder bore by the rotation of the swash plate as the drive shaft rotates, so that the refrigerant gas is compressed in the compression chamber defined in the cylinder bore. In a variable displacement swash plate compressor in which the discharge capacity is changed by changing the inclination angle of the swash plate, oil separation is performed in the discharge passage that guides the compressed refrigerant gas to the discharge port connected to the external refrigeration circuit. An oil storage chamber for storing separated lubricating oil, wherein the oil storage chamber and the swash plate chamber are communicated by a return oil passage, and the return oil passage increases as the volume of the compression chamber increases. It is characterized in that the oil chamber has a Kaeabura amount adjusting means for reducing the Kaeabura amount to the swash plate chamber.

  According to such a configuration, as the discharge capacity increases, the amount of return oil from the oil storage chamber to the swash plate chamber decreases. Therefore, the total amount of lubricant contained in the blow-by gas from the compression chamber can be adjusted to any discharge capacity. In contrast, a suitable amount of lubricating oil is always stored in the swash plate chamber.

Further, the return oil passage is constituted by a communication passage that communicates the oil storage chamber and the cylinder bore, and an oil guide groove that is provided in a circumferential surface of the piston that communicates the communication passage and the swash plate chamber. The amount adjusting means includes the swash plate capable of changing an inclination angle, the piston moored on the outer periphery of the swash plate, and the oil guide groove having a cross-sectional area equal to or smaller than a cross-sectional area of the communication path, The inclination angle of the swash plate is increased, the bottom dead center position of the piston is lowered, and the distance of the portion functioning as a part of the return oil passage of the oil guide groove is increased. It is preferable that the amount of oil returned to the board chamber is reduced.
According to such a configuration, the return oil passage and the return oil amount adjusting means can be formed by simple processing.

Alternatively, the return oil passage is constituted by a communication passage that communicates the oil storage chamber and the cylinder bore, and an oil guide groove that is provided on a circumferential surface of the cylinder bore that communicates the communication passage and the swash plate chamber, The amount adjusting means includes the swash plate capable of changing an inclination angle, the piston moored on the outer periphery of the swash plate, and the oil guide groove having a cross-sectional area equal to or smaller than a cross-sectional area of the communication path, The inclination angle of the swash plate is increased, the bottom dead center position of the piston is lowered, and the distance of the portion functioning as a part of the return oil passage of the oil guide groove is increased. The amount of oil returned to the board chamber may be reduced.
Even with such a configuration, the return oil passage and the return oil amount adjusting means can be formed by simple processing.

Alternatively, the radial clearance at the sliding surface between the cylinder bore and the piston is larger on the side connected to the swash plate chamber than on the side connected to the compression chamber, and the return oil passage connects the oil storage chamber and the cylinder bore. The communicating passage and the radial clearance communicating with the communicating passage and the swash plate chamber are configured, and the return oil amount adjusting means is moored on the swash plate capable of changing the inclination angle and the outer periphery of the swash plate. The piston and the radial clearance, the inclination angle of the swash plate is increased, the bottom dead center position of the piston is lowered, and the region functioning as a part of the return oil passage of the radial clearance. The amount of returned oil may be reduced by increasing the area.
According to such a configuration, when cutting the peripheral surfaces of the piston and the cylinder bore, part of the return oil passage and the return oil amount adjusting means can also be cut, so that the number of processes can be reduced.

Alternatively, the return oil passage is a communication passage that communicates the oil storage chamber and the cylinder bore, and the return oil amount adjusting means includes the swash plate capable of changing an inclination angle and the moored to the outer periphery of the swash plate. The piston is configured such that the inclination angle of the swash plate increases, the bottom dead center position of the piston decreases, and one end of the communication passage on the cylinder bore side is closed by the peripheral surface of the piston. The amount of oil may decrease.
Even with such a configuration, the return oil passage and the return oil amount adjusting means can be formed by simple processing.

Furthermore, it is preferable that a cross section of the communication passage on the cylinder bore side is an oval shape long in the piston sliding direction.
According to such a configuration, as the discharge capacity increases, when these communication passages are connected to the swash plate chamber, a rapid increase in the amount of return oil can be suppressed as compared to the case where the cross section is a perfect circle.

Furthermore, it is preferable that a plurality of the communication paths are provided in the piston sliding direction.
According to such a configuration, since the discharge capacity and the number of return oil passages opened to the swash plate chamber are proportional, the discharge capacity and the return oil amount can be more precisely proportional.

Further, the oil storage chamber and all the cylinder bores may communicate with each other through the communication passage.
According to such a configuration, since all the cylinder bores are returned to the oil almost uniformly, the lubricity and sealing performance between the piston and the cylinder bore are improved.

  According to the present invention, the amount of return oil from the oil storage chamber to the swash plate chamber decreases as the discharge capacity increases, so that a suitable amount of lubricating oil is always stored in the swash plate chamber for every discharge capacity.

(First embodiment)
Hereinafter, as an example in which the present invention is applied to a variable displacement swash plate compressor (hereinafter simply referred to as a “compressor”), a compressor according to a first embodiment will be described with reference to FIGS. 1 to 3. In the following description, for the “upper”, “lower”, “front”, and “rear” of the compressor, the direction of the arrow Y1 shown in FIG. 1 is the vertical direction, and the direction of the arrow Y2 is the front-back direction.

  FIG. 1 shows a cross-sectional view of the compressor 10 at an intermediate capacity. As shown in FIG. 1, the compressor 10 is joined via a valve / port forming body 13 to a cylinder block 11, a front housing 12 joined to the front end of the cylinder block 11, and a rear end of the cylinder block 11. Four housing constituent members, that is, a rear housing 14 and a flange 15 joined and fixed to the upper side of the cylinder block 11 are provided. The cylinder block 11, the front housing 12, the valve / port forming body 13 and the rear housing 14 are integrally fastened and fixed by fastening bolts 16. A plurality of fastening bolts 16 are provided, and only one fastening bolt 16 is shown in FIG.

  A swash plate chamber 20 is defined between the cylinder block 11 and the front housing 12, and a drive shaft 21 is rotatably supported so as to pass through the swash plate chamber 20. The drive shaft 21 is connected to an engine (not shown) that is a travel drive source of the vehicle.

  In the swash plate chamber 20, a disk-shaped lug plate 22 is fixed to the drive shaft 21 so as to be integrally rotatable. The swash plate chamber 20 accommodates a swash plate 23 as a disc-shaped cam plate. A hinge mechanism 24 is interposed between the lug plate 22 and the swash plate 23. The swash plate 23 can be rotated synchronously with the lug plate 22 and the drive shaft 21 by supporting the drive mechanism 21 and the hinge mechanism 24 between the lug plate 22 via the hinge mechanism 24 and the drive shaft. 21 can be tilted with respect to the drive shaft 21 while being slid in the central axis T direction.

  In the cylinder block 11, a plurality of cylinder bores 25 are formed in the front-rear direction at equal angular intervals around the central axis T. The single-headed piston 26 is accommodated in each cylinder bore 25 so as to be movable in the front-rear direction. That is, in the compressor 10, the same number of pistons 26 as the cylinder bores 25 are provided. The front / rear opening of the cylinder bore 25 is closed by a valve / port forming body 13 and a piston 26, and a compression chamber 27 whose volume changes in accordance with the movement of the piston 26 in the front / rear direction is defined in the cylinder bore 25. ing.

  In the valve / port forming body 13, a suction port 28 is formed radially inward and a discharge port 29 is formed radially outward at a position facing each cylinder bore 25. The valve / port forming body 13 is formed with a suction valve 30 for opening and closing the suction port 28 and a discharge valve 31 for opening and closing the discharge port 29.

  The stroke of the piston 26 includes the pressure applied to the front surface of the piston 26 (the surface facing the compression chamber 27 in FIG. 1), that is, the pressure of the compression chamber 27 (pressure in the cylinder bore 25) and the back surface of the piston 26 (swash plate chamber in FIG. 1). 20), that is, a pressure difference from the pressure in the swash plate chamber 20. For this reason, the piston stroke becomes smaller as the inclination angle of the swash plate 23 becomes smaller by increasing the pressure in the swash plate chamber 20 and increasing the pressure difference between the compression chamber 27 and the swash plate chamber 20. On the other hand, the piston stroke increases as the inclination angle of the swash plate 23 increases by reducing the pressure in the swash plate chamber 20 and reducing the differential pressure between the compression chamber 27 and the swash plate chamber 20.

  Each piston 26 is anchored to the outer periphery of the swash plate 23 via a pair of shoes 32. Accordingly, when the swash plate 23 is rotated by the rotation of the drive shaft 21, the swash plate 23 is swung back and forth in the direction of the central axis T of the drive shaft 21. The piston 26 is reciprocated linearly in the front-rear direction by the swing of the swash plate 23. In the compressor 10 of the present embodiment, a compression mechanism is configured by the swash plate chamber 20, the drive shaft 21, the swash plate 23, the piston 26, and the like.

  A suction chamber 33 and a discharge chamber 34 are defined in the rear housing 14, respectively. The discharge chamber 34 is formed outside the suction chamber 33 so as to surround the suction chamber 33. The rear housing 14 is formed with a suction port 35 for sucking refrigerant from the outside, and a suction passage 36 for introducing the refrigerant from the suction port 35 to the suction chamber 33, and discharges the refrigerant to the outside. A discharge port 37 and a discharge passage 38 for introducing the refrigerant from the discharge chamber 34 to the discharge port 37 are formed. The compressor 10 is provided with an extraction passage 39, an intake passage 40, and a control valve 41. The extraction passage 39 communicates the swash plate chamber 20 and the suction chamber 33, while the supply passage 40 is connected to the discharge chamber. 34 communicates with the swash plate chamber 20. A known control valve 41 made of an electromagnetic valve is disposed in the supply passage 40.

  An oil separation mechanism comprising an oil separation chamber 42 formed in a bottomed cylindrical shape and a separation cylinder 43 mounted in the oil separation chamber 42 is disposed in the middle of the discharge passage 38. An oil storage chamber 44 is defined in the area surrounded by the cylinder block 11 and the flange 15. In the rear housing 14, an oil supply passage 45 that connects the oil separation chamber 42 and the oil storage chamber 44 is formed, and in the cylinder block 11, a communication passage 46 that connects the oil storage chamber 44 and the cylinder bore 25 is formed. The sliding surface of the piston 26 is provided with an oil guide groove 47 whose cross-sectional area is equal to or smaller than the cross-sectional area of the communication passage 46 in the sliding direction. Lubrication in the oil storage chamber 44 is performed by the communication passage 46 and the oil guide groove 47. A return oil passage for guiding oil into the swash plate chamber 20 is formed. The swash plate 23, the piston 26, and the oil guide groove 47 constitute return oil amount adjusting means.

  An external refrigerant circuit 48 provided outside the compressor 10 is connected to the compressor 10, and the suction port 35 and the discharge port 37 are connected by the external refrigerant circuit 48. On the external refrigerant circuit 48, a condenser 48a, an expansion valve 48b, and an evaporator 48c are interposed.

Next, the operation of the compressor 10 according to this embodiment will be described.
When the drive shaft 21 is rotated by an engine (not shown), the swash plate 23 is swung back and forth in the direction of the central axis T of the drive shaft 21, and the piston 26 moored on the swash plate 23 is reciprocated in the cylinder bore 25. Accordingly, the refrigerant gas sucked from the suction chamber 33 is compressed in the compression chamber 27 and discharged to the discharge chamber 34. The compressed high-pressure refrigerant gas is introduced from the discharge chamber 34 into the oil separation chamber 42 through the discharge passage 38. The refrigerant gas that has entered from the discharge passage 38 into the oil separation chamber 42 along the cylindrical inner wall is swirled and then guided into the separation cylinder 43, via the discharge port 37, and the external refrigeration circuit 48. Is discharged. During this time, the mixed oil component in the refrigerant gas is separated by the centrifugal force based on the swirl flow. The separated lubricating oil passes through the oil supply passage 45 and is stored in the oil storage chamber 44. Thereafter, the fluid is returned to the swash plate chamber 20 through the communication passage 46 and the oil guide groove 47.

  The inclination angle of the swash plate 23 is determined by the pressure difference before and after the piston 26, that is, the difference between the pressure in the swash plate chamber 20 and the pressure in the cylinder bore 25. In the present embodiment, this differential pressure is adjusted by increasing or decreasing the pressure in the swash plate chamber 20. When reducing the discharge capacity, the opening of the control valve 41 is increased to release the high-pressure refrigerant gas in the discharge chamber 34 into the swash plate chamber 20 to increase the pressure in the swash plate chamber 20. Then, the inclination angle of the swash plate 23 becomes small, the stroke amount of the piston 26 decreases, and the discharge capacity decreases. On the contrary, when increasing the discharge capacity, the refrigerant gas in the discharge chamber 34 is prevented from being discharged into the swash plate chamber 20 by lowering the opening of the control valve. Then, since the pressure in the swash plate chamber 20 is lowered, the inclination angle of the swash plate 23 is increased, the stroke amount of the piston 26 is increased, and the discharge capacity is increased.

FIG. 2 is a cross-sectional view of the compressor 10 at the maximum capacity. As shown in FIG. 2, at the maximum capacity, the bottom dead center of the piston 26 moves to the front side of FIG. At this time, the distance of the portion functioning as a part of the return oil passage of the oil guide groove 47 becomes longer than that at the intermediate capacity as shown in FIG. 1, so that the throttle effect of the return oil amount adjusting mechanism is increased. Therefore, the amount of oil returned from the oil storage chamber 44 to the swash plate chamber 20 decreases. On the other hand, the amount of blow-by gas containing lubricating oil from the compression chamber 27 increases as the discharge capacity increases.
FIG. 3 is a cross-sectional view of the compressor 10 at the minimum capacity. As shown in FIG. 3, at the minimum capacity, the bottom dead center of the piston 26 moves to the rear side of FIG. At this time, the distance of the portion functioning as a part of the return oil passage of the oil guide groove 47 is shorter than that in the intermediate capacity as shown in FIG. 1, so that the throttle effect of the return oil amount adjusting mechanism is reduced. Therefore, the amount of oil returned from the oil storage chamber 44 to the swash plate chamber 20 increases. On the other hand, the amount of blow-by gas containing lubricating oil from the compression chamber 27 decreases as the discharge capacity decreases.
From the above, regardless of the discharge capacity, the amount of lubricating oil sent to the swash plate chamber 20 is substantially constant when the amount through the return oil passage and the amount contained in the blow-by gas are combined.

Therefore, according to the compressor of this embodiment, the following effects can be obtained.
(1) The oil storage chamber 44 and the swash plate chamber 20 communicate with each other through a return oil passage, and the return oil that reduces the amount of return oil from the oil storage chamber 44 to the swash plate chamber 20 as the volume of the compression chamber 27 increases in the return oil passage. A quantity adjusting means was provided. As a result, the amount of return oil through the return oil passage and the amount of lubricant contained in the blow-by gas are almost constant for all discharge capacities, so that a suitable amount of lubricant is always kept in the swash plate chamber 20. It came to be stored.

  (2) The return oil passage is constituted by a communication passage 46 that communicates between the oil storage chamber 44 and the cylinder bore 25, and an oil guide groove 47 provided in the piston 26 that communicates between the communication passage 46 and the swash plate chamber 20. The means is constituted by the swash plate 23, the piston 26 and the oil guiding groove 47. As a result, the return oil passage and the return oil amount adjusting means can be formed by simple processing.

(Second Embodiment)
Next, the compressor which concerns on 2nd Embodiment is demonstrated based on FIGS.
In this embodiment, the configurations of the return oil passage and the return oil amount adjusting means in the first embodiment are changed, and other configurations are common. Therefore, here, for convenience of explanation, some of the reference numerals used in the previous explanation are used in common, explanation of common configurations is omitted, and only the changed parts are explained.

  As shown in FIG. 4, the oil storage chamber 44 is communicated with the cylinder bore 25 by a communication passage 46. An oil guide groove 49 is provided on the sliding surface of the cylinder bore 25 in the piston sliding direction. The return oil guides the lubricating oil in the oil storage chamber 44 into the swash plate chamber 20 by the communication passage 46 and the oil guide groove 49. A passage is constructed. The swash plate 23, the piston 26, and the oil guide groove 49 constitute return oil amount adjusting means.

FIG. 5 is a cross-sectional view of the compressor 10 at the maximum capacity. As shown in FIG. 5, at the maximum capacity, the bottom dead center of the piston 26 moves to the front side of FIG. At this time, the distance of the portion functioning as a part of the return oil passage of the oil guide groove 49 is longer than that in the intermediate capacity as shown in FIG. 4, so that the throttle effect of the return oil amount adjusting mechanism is increased. Therefore, the amount of oil returned from the oil storage chamber 44 to the swash plate chamber 20 decreases. On the other hand, the amount of blow-by gas containing lubricating oil from the compression chamber 27 increases as the discharge capacity increases.
FIG. 6 is a cross-sectional view of the compressor 10 at the minimum capacity. As shown in FIG. 6, at the maximum capacity, the bottom dead center of the piston 26 moves to the rear side of FIG. At this time, the distance of the portion functioning as a part of the return oil passage of the oil guide groove 49 is shorter than that at the intermediate capacity as shown in FIG. Therefore, the amount of oil returned from the oil storage chamber 44 to the swash plate chamber 20 increases. On the other hand, the amount of blow-by gas containing lubricating oil from the compression chamber 27 decreases as the discharge capacity decreases.
From the above, regardless of the discharge capacity, the amount of lubricating oil sent to the swash plate chamber 20 is substantially constant when the amount through the return oil passage and the amount contained in the blow-by gas are combined.

Therefore, according to the compressor of the present embodiment, in addition to the same effect as the effect (1) of the first embodiment, the following effects can be obtained.
(3) The return oil passage is constituted by a communication passage 46 that communicates between the oil storage chamber 44 and the cylinder bore 25, and an oil guide groove 49 provided in the cylinder bore 25 that communicates between the communication passage 46 and the swash plate chamber 20, thereby adjusting the amount of return oil. The means is constituted by the swash plate 23, the piston 26 and the oil guide groove 49. As a result, the return oil passage and the return oil amount adjusting means can be formed by simple processing.

(Third embodiment)
Next, the compressor which concerns on 3rd Embodiment is demonstrated based on FIGS.
In this embodiment, the configurations of the return oil passage and the return oil amount adjusting means in the first embodiment are changed, and other configurations are common. Therefore, here, for convenience of explanation, some of the reference numerals used in the previous explanation are used in common, explanation of common configurations is omitted, and only the changed parts are explained.

  As shown in FIG. 7, which is a partially enlarged view of the compressor 10 at the intermediate capacity, the oil storage chamber 44 is communicated with the cylinder bore 25 through the communication passage 46. Since the outer diameter of the piston 26 is smaller on the swash plate chamber 20 side than on the opposite side, the radial clearance 50 between the cylinder bore 25 and the piston 26 is the lubricating oil coming from the oil storage chamber 44 via the communication passage 46. Is formed so as to actively guide the oil in the swash plate chamber 20, and the communication passage 46 and the radial clearance 50 constitute a return oil passage for guiding the lubricating oil in the oil storage chamber 44 into the swash plate chamber 20. The swash plate 23, the piston 26 and the radial clearance 50 constitute return oil amount adjusting means.

FIG. 8 is a cross-sectional view of the compressor 10 at the maximum capacity. As shown in FIG. 8, at the maximum capacity, the bottom dead center of the piston 26 moves to the front side of FIG. At this time, the area of the region functioning as a part of the return oil passage of the radial clearance 50 becomes larger than that in the intermediate capacity as shown in FIG. 7, so that the throttle effect of the return oil amount adjusting mechanism is increased. Therefore, the amount of oil returned from the oil storage chamber 44 to the swash plate chamber 20 decreases. On the other hand, the amount of blow-by gas containing lubricating oil from the compression chamber 27 increases as the discharge capacity increases.
FIG. 9 is a sectional view of the compressor 10 at the minimum capacity. As shown in FIG. 9, at the minimum capacity, the bottom dead center of the piston 26 moves to the rear side of FIG. At this time, since the area of the region functioning as a part of the return oil passage of the radial clearance 50 is smaller than that in the intermediate capacity as shown in FIG. 7, the throttle effect of the return oil amount adjusting mechanism is reduced. Therefore, the amount of oil returned from the oil storage chamber 44 to the swash plate chamber 20 increases. On the other hand, the amount of blow-by gas containing lubricating oil from the compression chamber 27 decreases as the discharge capacity decreases.
From the above, regardless of the discharge capacity, the amount of lubricating oil sent to the swash plate chamber 20 is substantially constant when the amount through the return oil passage and the amount contained in the blow-by gas are combined.

Therefore, according to the compressor of this embodiment, in addition to the effect similar to the effect (1) of 1st Embodiment, the effect shown below can be acquired.
(4) The outer diameter of the piston 26 is reduced on the swash plate chamber 20 side compared to the opposite side, the return oil passage is slid between the oil storage chamber 44 and the cylinder bore 25, and the cylinder bore 25 and the piston 26 are slid. The return oil amount adjusting means is constituted by the swash plate 23, the piston 26, and the radial clearance 50. Thereby, when cutting the peripheral surface of the piston 26, part of the return oil passage and the return oil amount adjusting means can also be cut, so that the number of processes can be reduced.

(Fourth embodiment)
Next, the compressor which concerns on 4th Embodiment is demonstrated based on FIGS.
In this embodiment, the configurations of the return oil passage and the return oil amount adjusting means in the first embodiment are changed, and other configurations are common. Therefore, here, for convenience of explanation, some of the reference numerals used in the previous explanation are used in common, explanation of common configurations is omitted, and only the changed parts are explained.

  As shown in FIG. 10, the oil storage chamber 44 is communicated with the cylinder bore 25 through the communication passage 51. Further, the communication passage 51 has its cylinder bore end branched in parallel with the piston sliding direction 51a, 51b, 51c. The communication passage 51 functions as a return oil passage, and the cross-sections of the communication passages 51a, 51b, 51c are in the shape of an ellipse that is long in the piston sliding direction as shown in FIG. The swash plate 23 and the piston 26 constitute return oil amount adjusting means. Further, as shown in FIG. 12, which is a cross-sectional view as seen from the rear in FIG. 10, a part of the communication passage 51 is formed in an annular shape on the surface of the cylinder block 11 on the rear housing 14 side, whereby all cylinder bores are formed. 25 and the oil storage chamber 44 are connected.

FIG. 13 is a cross-sectional view of the compressor 10 at the maximum capacity. As shown in FIG. 13, at the maximum capacity, the bottom dead center of the piston 26 moves to the front side of FIG. At this time, since the communication passages 51a and 51b opened to the swash plate chamber 20 in the intermediate capacity as shown in FIG. Therefore, the amount of oil returned from the oil storage chamber 44 to the swash plate chamber 20 decreases. On the other hand, the amount of blow-by gas containing lubricating oil from the compression chamber 27 increases as the discharge capacity increases.
FIG. 14 is a cross-sectional view of the compressor 10 at the minimum capacity. As shown in FIG. 14, at the minimum capacity, the bottom dead center of the piston 26 moves to the rear side of FIG. At this time, the communication passage 51c that is blocked by the piston 26 at the intermediate capacity as shown in FIG. 10 is opened to the swash plate chamber 20, so that the throttle effect is reduced. Therefore, the amount of oil returned from the oil storage chamber 44 to the swash plate chamber 20 increases. On the other hand, the amount of blow-by gas containing lubricating oil from the compression chamber 27 decreases as the discharge capacity decreases.
From the above, regardless of the discharge capacity, the amount of lubricating oil sent to the swash plate chamber 20 is substantially constant when the amount through the return oil passage and the amount contained in the blow-by gas are combined. Further, since the communication passage 51 is connected to all the cylinder bores including those not shown, the oil is returned almost uniformly to all the cylinder bores. Therefore, this structure can be employed to positively lubricate and seal the piston 26 and the cylinder bore 25.

Therefore, according to the compressor of the present embodiment, the following effects can be obtained.
(5) The return oil passage is a communication passage 51 that communicates between the oil storage chamber 44 and the cylinder bore 25, and the return oil amount adjusting means is constituted by the swash plate 23 and the piston 26. As a result, the return oil passage and the return oil amount adjusting means can be formed by simple processing.

  (6) The cross sections of the communication passages 51a, 51b, and 51c have an oval shape that is long in the piston sliding direction. As a result, as these discharge capacities increase, when these communication paths are closed by the piston 26, a rapid decrease in the amount of return oil can be suppressed.

  (7) A plurality of communication passages 51 are provided in the sliding direction of the piston 26. As a result, the discharge capacity and the number of return oil passages opened to the swash plate chamber 20 are inversely proportional, so that the discharge capacity and the amount of return oil can be more precisely inversely proportional.

  (8) The oil storage chamber 44 and all the cylinder bores 25 are communicated with each other through the communication passage 51. Thereby, the lubricity and sealing performance between the piston 26 and the cylinder bore 25 were improved.

In addition, you may change the said embodiment as follows.
In FIG. 1, as shown in FIG. 15, the oil guide groove 52 may be provided in a spiral shape on the peripheral surface of the piston 26, and the communication path 53 may be formed in a long hole shape so as to be always in contact with the oil guide groove 51. Thereby, a return oil path can be made longer.
10-14, the cross sections of the communication passages 51a, 51b, 51c are elongated holes, but other shapes such as rectangles and diamonds may be used as long as they are extended in the piston sliding direction.

Sectional drawing at the time of intermediate capacity of the capacity variable type swash plate compressor according to the first embodiment Sectional drawing at the time of the maximum capacity | capacitance of the capacity | capacitance variable swash plate type compressor which concerns on 1st Embodiment. Sectional drawing at the time of the minimum capacity | capacitance of the capacity | capacitance variable type swash plate type compressor which concerns on 1st Embodiment Sectional view at the time of intermediate capacity of the capacity variable type swash plate compressor according to the second embodiment Sectional drawing at the time of the maximum capacity | capacitance of the capacity | capacitance variable swash plate type compressor which concerns on 2nd Embodiment. Sectional drawing at the time of the minimum capacity | capacitance of the capacity | capacitance variable swash plate type compressor which concerns on 2nd Embodiment. Enlarged view of variable capacity swash plate compressor according to the third embodiment at the time of intermediate capacity The enlarged view at the time of the maximum capacity | capacitance of the capacity | capacitance variable type swash plate type compressor which concerns on 3rd Embodiment. The enlarged view at the time of the minimum capacity | capacitance of the capacity | capacitance variable type swash plate type compressor which concerns on 3rd Embodiment. Sectional drawing at the time of the intermediate capacity of the capacity variable type swash plate compressor according to the fourth embodiment The fragmentary sectional view of the communicating path of the capacity variable type swash plate compressor according to the fourth embodiment Sectional drawing seen from the rear side of the capacity | capacitance variable type swash plate type compressor which concerns on 4th Embodiment Sectional drawing at the time of the maximum capacity | capacitance of the capacity | capacitance variable type swash plate type compressor which concerns on 4th Embodiment Sectional drawing at the time of the minimum capacity | capacitance of the capacity | capacitance variable type swash plate type compressor which concerns on 4th Embodiment Sectional drawing at the time of intermediate capacity of the capacity variable type swash plate type compressor concerning the modification of a 1st embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Variable displacement type swash plate compressor, 20 ... Swash plate chamber, 27 ... Compression chamber, 33 ... Suction chamber, 34 ... Discharge chamber, 38 ... Discharge passage, 42 ... Oil separation chamber, 43 ... separation cylinder, 44 ... oil storage chamber, 45 ... oil supply passage, 46 ... communication passage, 47 ... oil guide groove, 49 ... oil guide groove, 50 ... Radial clearance, 51 ... Communication passage, 51a ... Communication passage, 51b ... Communication passage, 51c ... Communication passage, 52 ... Oil guide groove, 53 ... Communication passage

Claims (8)

A swash plate accommodated in the swash plate chamber is connected to the drive shaft so as to be integrally rotatable and changeable in inclination angle, and a piston is moored on the outer periphery of the swash plate via a shoe, and the drive shaft is rotated. The piston is reciprocated linearly in the cylinder bore by the rotation of the swash plate, the refrigerant gas is compressed in the compression chamber defined in the cylinder bore, and the discharge angle is changed by changing the inclination angle of the swash plate. In variable capacity swash plate compressors whose capacity is changed,
An oil separation mechanism is provided in the discharge passage for leading the compressed refrigerant gas to the discharge port connected to the external refrigeration circuit, and an oil storage chamber for storing the separated lubricating oil is provided. The oil storage chamber and the swash plate chamber are the return oil passage. The return oil passage is provided with return oil amount adjusting means for reducing the return oil amount from the oil storage chamber to the swash plate chamber as the volume of the compression chamber increases. Variable swash plate compressor. The return oil passage is constituted by a communication passage that communicates the oil storage chamber and the cylinder bore, and an oil guide groove that is provided on the circumferential surface of the piston that communicates the communication passage and the swash plate chamber.
The return oil amount adjusting means includes the swash plate capable of changing an inclination angle, the piston moored on the outer periphery of the swash plate, and the oil guide groove whose cross-sectional area is equal to or smaller than the cross-sectional area of the communication path. And
The inclination angle of the swash plate is increased, the bottom dead center position of the piston is lowered, and the distance of the portion functioning as a part of the return oil passage of the oil guide groove is increased, so that the oil storage chamber 2. A variable displacement swash plate compressor according to claim 1, wherein the amount of oil returned to the swash plate chamber is reduced. The return oil passage is constituted by a communication passage that communicates the oil storage chamber and the cylinder bore, and an oil guide groove that is provided on a peripheral surface of the cylinder bore that communicates the communication passage and the swash plate chamber.
The return oil amount adjusting means includes the swash plate capable of changing an inclination angle, the piston moored on the outer periphery of the swash plate, and the oil guide groove whose cross-sectional area is equal to or smaller than the cross-sectional area of the communication path. And
The inclination angle of the swash plate is increased, the bottom dead center position of the piston is lowered, and the distance of the portion functioning as a part of the return oil passage of the oil guide groove is increased, so that the oil storage chamber 2. A variable displacement swash plate compressor according to claim 1, wherein the amount of oil returned to the swash plate chamber is reduced. The radial clearance at the sliding surface between the cylinder bore and the piston is larger on the side connected to the swash plate chamber than on the side connected to the compression chamber,
The return oil passage is constituted by a communication passage that communicates the oil storage chamber and the cylinder bore, and the radial clearance that communicates the communication passage and the swash plate chamber.
The return oil amount adjusting means includes the swash plate capable of changing an inclination angle, the piston moored on the outer periphery of the swash plate, and the radial clearance.
As the tilt angle of the swash plate increases, the bottom dead center position of the piston decreases, and the area of the radial clearance that functions as part of the return oil passage increases, the amount of return oil decreases. The capacity-variable swash plate compressor according to claim 1. The return oil passage is a communication passage communicating the oil storage chamber and the cylinder bore;
The return oil amount adjusting means is constituted by the swash plate capable of changing an inclination angle, and the piston moored on the outer periphery of the swash plate,
The tilt angle of the swash plate is increased, the bottom dead center position of the piston is lowered, and one end of the communication passage on the cylinder bore side is closed by the peripheral surface of the piston, thereby reducing the amount of return oil. The capacity-variable swash plate compressor according to claim 1.   6. The variable displacement swash plate compressor according to claim 5, wherein a cross section of the communication passage on the cylinder bore side is an oval shape long in a piston sliding direction.   The variable displacement swash plate compressor according to claim 5 or 6, wherein a plurality of the communication passages are provided in the piston sliding direction.   The variable capacity swash plate compressor according to any one of claims 1 to 7, wherein the oil storage chamber and all the cylinder bores communicate with each other through the return oil passage.

Images