JP2020165425A - Variable displacement swash plate compressor - Google Patents

Abstract

To provide a variable displacement swash plate compressor capable of securing good lubrication of a shaft seal member by actively supplying oil to a seal chamber, promoting cooling of the shaft seal member and avoiding shortage of oil in a crank chamber regardless of rotational frequency.SOLUTION: In a variable displacement swash plate compressor, oil is supplied from a crank chamber 6 via an oil supply passage 35 to a seal chamber 33 formed between a radial bearing 11 supporting a drive shaft 7 and a shaft seal member 10 sealing a space between the drive shaft 7 and a housing. The drive shaft 7 includes: a shaft hole 41 communicated with a suction chamber 31 and extended axially from a rear end to a front end of the drive shaft 7; a first side hole 42 extended in the radial direction and communicating the seal chamber 33 with the shaft hole 41 all the time; and a second side hole 43 extended in the radial direction and communicating the crank chamber 6 with the shaft hole 41 all the time. The first side hole 42 may be provided on the side having a link mechanism 19 relative to the shaft hole 41 of the drive shaft 7.SELECTED DRAWING: Figure 1

Description

The present invention relates to a variable displacement swash plate compressor capable of adjusting the discharge capacity by adjusting the pressure in the crank chamber, and in particular, a shaft seal provided around the drive shaft and sealed between the compressor and the housing. The present invention relates to a compressor that improves the flow state of oil (lubricating oil) supplied to a member.

In a variable displacement swash plate compressor that adjusts the discharge capacity by adjusting the tilt angle of the swash plate by adjusting the pressure in the crank chamber, the drive shaft is rotatably supported by the housing so as to penetrate the crank chamber. A swash plate that rotates with the rotation of the drive shaft is housed in the crank chamber. One end of the drive shaft projects to the outside of the housing and is connected to a power transmission device for transmitting the driving force from the vehicle drive source.
In such a compressor, a shaft sealing member (shaft seal) is provided between the drive shaft and the housing to prevent the refrigerant in the crank chamber from leaking to the outside of the compressor.

The crank chamber is required to function as a control pressure chamber for changing the inclination angle of the swash plate, and the crank chamber cannot be used as a part of the suction path. For this reason, the low-pressure refrigerant mixed with lubricating oil sucked in from the refrigeration cycle cannot lubricate the parts in the crank chamber, and the oil stored in the crank chamber is splashed by the rotation of the swash plate to lubricate the parts in the crank chamber. I try to do it.

However, since the shaft sealing member is arranged in the seal chamber separated from the crank chamber by the bearing provided on the wall of the housing as a boundary, the oil agitated by the swash plate becomes mist-like. Hard to reach. Therefore, a stable oil supply to the shaft sealing member is required. Further, since the shaft sealing member is in sliding contact with the peripheral surface of the drive shaft, sludge is likely to be generated due to sliding heat generation. Therefore, it is also required to appropriately cool the sealing member.

For this reason, conventionally, the crank chamber and the seal chamber are connected by an oil supply passage, the oil adhering to the inner wall surface of the housing is guided to the seal chamber, and the seal chamber and the crank chamber are connected by an oil discharge passage. , A configuration has been proposed in which the oil guided to the seal chamber is discharged to the crank chamber. Here, the oil discharge passage is arranged above the lowest position where the drive shaft and the shaft sealing member come into contact with each other and below the axis of the drive shaft, and the oil introduced into the seal chamber is steadily transferred. The shaft sealing member and the sliding surface of the drive shaft are brought into contact with each other, and oil is prevented from staying in the seal chamber more than necessary (see 1st prior art: Patent Document 1).

Further, the drive shaft is provided with a pressure discharge passage that is bored in the axial direction and communicates with the suction chamber, and a radial passage that is bored in the radial direction and communicates with the pressure discharge passage and the seal chamber. The refrigerant is positively guided to the seal chamber by using the differential pressure between the crank chamber and the suction chamber, and the oil supplied to the seal chamber is discharged to the suction chamber through the radial passage and the pressure release passage. (2nd prior art: see Patent Document 2), a passage extending along the axial direction is formed at the center of the drive shaft, and the first is connected to the seal chamber by branching in the radial direction from this axial passage. And a second passage that branches radially from the axial passage and connects to the crank chamber, and a valve that opens and closes by centrifugal force due to the rotation of the drive shaft is provided in the second passage during high-speed rotation. A configuration in which the second passage is closed and the second passage is opened at low speed rotation has also been proposed (see Third Conventional Technology: Patent Document 3).

Japanese Unexamined Patent Publication No. 2016-65459 Japanese Patent Application Laid-Open No. 08-109880 JP-A-2009-209682

However, in the first conventional technique, the oil adhering to the wall surface of the housing is guided to the seal chamber through the oil supply passage by gravity, and the oil is not positively sucked into the seal chamber. Insufficient supply of oil to the seal chamber may cause the temperature of the seal chamber to rise and cause poor lubrication of the sliding portion between the drive shaft and the shaft sealing member.

On the other hand, in the second conventional technique, the oil in the seal chamber is sucked by the pressure difference between the crank chamber and the suction chamber, so that the oil adhering to the wall surface of the crank chamber can be positively guided to the seal chamber. It can also be done, and oil does not stay in the seal chamber. However, in the second conventional technique, the working fluid of the crank chamber is discharged to the suction chamber only through the radial passage and the pressure release passage connected to the seal chamber, so that the difference between the crank chamber and the suction chamber. As long as there is pressure, there is concern that the oil in the crank chamber will flow out through the pressure release passage and all the oil in the crank chamber will be discharged to the suction chamber via the seal chamber.

In this regard, in the third prior art, in addition to the first passage connecting the seal chamber and the axial passage, a second passage capable of connecting the crank chamber and the axial passage is added to the drive shaft. By releasing the refrigerant gas from the second passage, the effect of relatively reducing the amount of oil released through the first passage can be obtained. Further, the second passage is provided with a valve that opens and closes by centrifugal force due to the rotation of the drive shaft, and the following effects are expected.
First, since the second passage is closed during high-speed rotation, the oil splashed on the wall surface of the crank chamber due to the rotation of the swash plate travels along the wall surface and passes through the oil supply passage due to the pressure difference between the crank chamber and the suction chamber. It is introduced into the seal chamber through and then discharged into the suction chamber via the first passage and the axial passage. This makes it possible to actively introduce oil into the seal chamber to ensure the reliability of the shaft seal member, and to discharge excess oil in the crank chamber to prevent the temperature of the crank chamber from rising due to oil agitation. Become.
Further, during low-speed operation, the valve provided in the second passage is opened, so that the working fluid in the crank chamber is discharged from the second passage of the drive shaft to the suction chamber via the axial passage. Here, since the oil is repelled to the outer peripheral side by the rotation of the sloping plate and is in an oil-poor state around the second passage, the oil flowing into the axial passage of the drive shaft via the second passage It is suppressed and only the refrigerant gas flows into the axial passage.
Therefore, since the refrigerant gas flows into the axial passage of the drive shaft through the second passage, the oil flowing into the axial passage from the seal chamber through the first passage (discharged to the suction chamber). The amount of oil produced) is relatively reduced, which makes it possible to retain the oil in the crank chamber and lubricate the mechanical parts during low-speed operation.

However, in such a configuration, since the ratio of the oil flowing through the first passage changes due to the fluctuation of the rotation speed, there is a disadvantage that the amount of oil in the crank chamber does not reach an appropriate level immediately after the rotation speed changes. For example, if the high-speed rotation continues for a predetermined time, the oil in the crank chamber is discharged through the first passage, and the oil in the crank chamber is reduced. After that, when the rotation shifts to low speed, the valve provided in the second passage opens to reduce the amount of oil discharged from the first passage and work to retain the oil in the crank chamber. , Excess oil has been discharged during high-speed operation, and the oil has decreased. Especially when the rotation speed drops to the idle state, the pressure control valve closes the air supply passage to reduce the pressure in the crank chamber in order to maximize the discharge capacity, so that the working fluid from the discharge chamber to the crank chamber The supply of oil is stopped and the oil in the crank chamber remains insufficient, which may impair reliability.

The present invention has been made in view of the above circumstances, and the oil is positively supplied to the sealing chamber to ensure good lubrication of the shaft sealing member and promote cooling of the shaft sealing member, while rotating the number of revolutions. Despite this, the main issue is to provide a variable displacement swash plate compressor that can avoid a shortage of oil in the crank chamber.

In order to achieve the above object, in the compressor according to the present invention, the crank chamber is defined, and the housing in which the suction chamber and the discharge chamber are formed and the housing through the crank chamber are provided with a radial bearing. A drive shaft that is rotatably supported and one end of which protrudes from the housing, a swash plate that is housed in the crank chamber and rotates in synchronization with the rotation of the drive shaft, and a radial bearing of the drive shaft. A shaft sealing member arranged on the one end side and sealing between the drive shaft and the housing, and a shaft sealing member formed in the housing, one end communicating with the crank chamber and the other end communicating with the radial bearing and the shaft. The discharge chamber is provided with an oil supply passage that communicates with the seal chamber formed between the sealing member and the discharge chamber in order to control the pressure in the crank chamber and control the inclination angle of the swash plate with respect to the drive shaft. In a variable-capacity swash plate type compressor having an air supply passage that communicates with the crank chamber and a pressure control valve that adjusts the opening degree of the air supply passage, the drive shaft communicates with the suction chamber. A shaft hole extending axially from the rear end to the front end of the drive shaft, a first side hole extending radially and always communicating the seal chamber and the shaft hole, and a radial direction. It is characterized in that it is provided with a second side hole that is extended and always communicates with the crank chamber and the shaft hole.

In such a configuration, the pressure in the crank chamber is higher than the pressure in the suction chamber during operation of the compressor. Therefore, the pressure difference between the crank chamber and the suction chamber causes the pressure difference between the crank chamber and the suction chamber to be around the drive shaft of the crank chamber. The refrigerant gas is guided to the shaft hole through the second shaft hole which is always open, and is discharged to the suction chamber. Further, the oil splashed on the wall surface of the crank chamber by the rotation of the swash plate is positively guided to the seal chamber through the oil supply passage along the wall surface, and then through the first shaft hole and the shaft hole. Is released into the inhalation chamber.

Therefore, since the shaft hole is used both as a discharge passage for the refrigerant gas introduced from the second shaft hole and as a discharge passage for the oil introduced from the first shaft hole, the shaft hole is used from the first shaft hole. The amount of oil discharged into the suction chamber through the air is relatively reduced as compared with the state where the second shaft hole is not provided or the second shaft hole is closed. Therefore, regardless of the number of revolutions (whether at high speed or low speed), the oil is positively guided to the seal chamber through the oil supply passage, while the oil released from the seal chamber is released. It is possible to avoid the inconvenience of becoming excessive, and it is possible to avoid the inconvenience of depleting the oil in the crank chamber while lubricating and cooling the shaft sealing member.

In order to effectively obtain the above-mentioned actions (lubrication and cooling of the shaft sealing member by actively introducing oil into the seal chamber and avoidance of excessive oil discharge), the passage cross section of the first side hole is formed. It is desirable to make it smaller than the passage cross section of the second side hole.
Further, it is preferable to use a plain bearing as the radial bearing. By using a plain bearing, the oil introduced into the seal chamber can be well retained in this seal chamber, and good lubrication and cooling of the shaft seal member and good lubrication of the radial bearing (plain bearing) can be achieved. It becomes possible to secure.

When a plain bearing is used as the radial bearing, it is desirable that the passage area of the first shaft hole is substantially equal to the clearance area between the plain bearing and the drive shaft.
By doing so, it is possible to use an amount equivalent to the amount of oil discharged from the seal chamber to the suction chamber for lubrication of the plain bearing, and it is possible to effectively suppress seizure of the plain bearing.

Further, in a configuration in which a thrust flange fixed to the drive shaft and rotatably supported with respect to the inner wall surface of the housing is connected to the swash plate via a link mechanism, the first side hole is formed. , It is preferable that the drive shaft is provided on the side where the link mechanism is provided with respect to the shaft hole. That is, the first side hole is a plane orthogonal to the axial center of the drive shaft and the plane including the link mechanism, and the link mechanism is defined by the plane including the axial center of the drive shaft as a boundary. It is preferable to provide it on the side where it is provided.
In particular, it is preferable to provide the first side hole in a range of ± 50 ° with respect to the phase position in the rotation direction of the link mechanism.
In such a configuration, oil is easily guided to the sliding portion between the drive shaft and the radial bearing, heat generation at the sliding contact portion of the radial bearing is suppressed, and the temperature around the shaft sealing member is relatively low. Therefore, it is possible to suppress the generation of sludge due to high temperature.

As described above, according to the present invention, the variable capacitance diagonal having an oil supply passage having one end communicating with the crank chamber and the other end communicating with the seal chamber formed between the radial bearing and the shaft sealing member. In a plate type compressor, the drive shaft communicates with the suction chamber and extends axially from the rear end to the front end of the drive shaft, and the seal chamber and the shaft extend radially. Since a first side hole for constantly communicating with the hole and a second side hole extending in the radial direction for constantly communicating with the crank chamber and the shaft hole are provided, the oil can be supplied to the oil supply passage. It is possible to positively supply to the seal chamber through the shaft to ensure good lubrication of the shaft seal member and promote cooling of the shaft seal member, and to avoid a shortage of oil in the crank chamber regardless of the number of rotations. It becomes possible.

FIG. 1 is a cross-sectional view showing a compressor according to an embodiment of the present invention, and is a diagram showing a state in which a swash plate has a large swing angle. FIG. 2 is a cross-sectional view showing a compressor according to an embodiment of the present invention, and is a diagram showing a state in which the swing angle of the swash plate is small. FIG. 3 is an enlarged cross-sectional view of a part of the front side where the shaft sealing member of the compressor is provided. FIG. 4A is a diagram showing a first side hole, FIG. 4B is a diagram showing a clearance α between a drive shaft and a radial bearing (plain bearing), and FIG. 4C is a diagram showing a first side hole. It is a figure which shows the side hole of 2. FIG. 5 shows a thrust flange connected to the diagonal plate of the compressor via a link mechanism, a shaft Assy to which the thrust flange is fixed and composed of a drive shaft, and a radial bearing supporting the drive shaft of the shaft Assy. It is a view seen from the front, and the drive shaft is a view cut at the portion of the first side hole. FIG. 6 shows an example of a sample in which the phase angle of the first side hole is changed in the advance angle direction from the position corresponding to the bottom dead center of the drive shaft, and FIG. 6 (1) is at a position of a phase angle of 15 °. A sample with a first side hole is shown, (2) shows a sample with a first side hole at a phase angle of 80 °, and (3) shows a sample with a phase angle of 130 °. A sample with a first side hole is shown, (4) shows a sample with a first side hole at a phase angle of 215 °, and (5) shows a sample with a phase angle of 245 °. It is a figure which shows the EUT which provided the 1st side hole. FIG. 7 is a diagram illustrating a lubrication state of a sliding contact portion between the drive shaft and the radial bearing when the first side hole is provided in a range of ± 50 ° from the phase position where the link mechanism is provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIGS. 1 and 2, a variable capacitance type swash plate compressor used in a refrigeration cycle is shown as an example of a compressor. This compressor has a cylinder block 1, a rear head 3 assembled on the rear side (right side in the figure) of the cylinder block 1 via a valve plate 2, and a front side (left side in the figure) of the cylinder block 1. It is configured to have a front head 4 assembled so as to be closed. The front head 4, the cylinder block 1, the valve plate 2, and the rear head 3 are axially fastened by fastening bolts 5, and form the housing of the entire compressor.

The crank chamber 6 defined by the front head 4 and the cylinder block 1 is accommodated so that a drive shaft 7 having one end protruding from the front head 4 passes through the crank chamber 6. A drive pulley (not shown) connected to the engine of the vehicle via a belt is fixed to a portion of the drive shaft 7 protruding from the front head 4. Further, one end side of the drive shaft 7 is airtightly sealed between the drive shaft 7 and the front head 4 via a shaft sealing member 10 provided between the drive shaft 7 and the drive shaft 7 to prevent refrigerant leakage along the drive shaft 7. I try to do it.

Then, one end side of the drive shaft 7 is rotatably supported by a radial bearing 11 housed on the crank chamber side of the shaft sealing member 10 of the front head 4, and the other end side of the drive shaft 7 is the cylinder block 1. It is rotatably supported by a radial bearing 12 housed in. These radial bearings 11 and 12 are made of well-known plain bearings. The plain bearing has an annular shape, and is composed of a steel back metal and a sliding layer containing a solid lubricant formed on the inner diameter side of the back metal in a multi-layered manner.

The cylinder block 1 is formed with a support hole 13 in which the radial bearing 12 is housed, and a plurality of cylinder bores 14 arranged at equal intervals on the circumference centered on the support hole 13. A single-headed piston 15 is inserted into the cylinder bore 14 so as to be reciprocally slidable. The single-headed piston 15 is formed by axially joining the head portion 15a inserted into the cylinder bore 14 and the engaging portion 15b protruding into the crank chamber 6.

A thrust flange 17 that rotates integrally with the drive shaft 7 is fixed to the drive shaft 7 in the crank chamber 6. The thrust flange 17 is rotatably supported via an annular thrust bearing 18 with respect to the inner wall surface of the front head 4 formed substantially perpendicular to the drive shaft 7. A swash plate 20 is connected to the thrust flange 17 via a link mechanism 19.

The swash plate 20 is slidably attached around a hinge ball 21 slidably provided on the drive shaft 7, and is integrally integrated with the rotation of the thrust flange 17 via the link mechanism 19. It is designed to rotate. The engaging portion 15b of the single-headed piston 15 is moored to the peripheral edge of the swash plate 20 via a pair of shoes 22 arranged in the front-rear direction.

Therefore, when the drive shaft 7 rotates, the swash plate 20 rotates accordingly, and the rotational motion of the swash plate 20 is converted into a reciprocating linear motion of the single-headed piston 16 via the shoe 22, and the single-headed piston 16 in the cylinder bore. The volume of the compression chamber 23 formed between the valve plate 2 and the valve plate 2 is changed.

The rear head 3 is formed with a suction chamber 31 and a discharge chamber 32 formed on the outside of the suction chamber 31. Further, the valve plate 2 has a suction hole 24 that communicates the suction chamber 31 and the compression chamber 23 via a suction valve (not shown), and a discharge valve (not shown) between the discharge chamber 32 and the compression chamber 23. A discharge hole 25 is formed so as to communicate with each other.

The cylinder block 1, the valve plate 2, and the rear head 3 are formed with an air supply passage 26 that communicates the discharge chamber 32 and the crank chamber 6. The opening degree of the air supply passage 26 is adjusted by the pressure control valve 27, and the pressure control valve 27 adjusts the flow rate of the refrigerant flowing from the discharge chamber 32 to the crank chamber 6 through the air supply passage 26. The pressure in the crank chamber 6 is controlled.

The pressure control valve 27 is well known in itself, for example, a diaphragm that responds to the suction pressure of the compressor, a plunger that is displaced by the amount of electricity applied to the solenoid, the movement of the diaphragm, and the amount of electricity applied to the solenoid (movement of the plunger). It is equipped with a solenoid that changes the opening of the air supply passage according to the air supply passage, and when the heat load increases (the passenger compartment becomes hot), the suction pressure increases, and the amount of electricity increases, the valve closes the valve opening. As the body moves, the amount of refrigerant supplied from the discharge chamber 32 to the crank chamber 6 decreases or stops, the crank chamber pressure is lowered, and the swing angle of the swash plate 20 is increased (see FIG. 1). ). Further, when the heat load changes from a medium load to a low load (the interior of the vehicle becomes cold), the suction pressure decreases, and the amount of electricity applied to the solenoid decreases, the valve body moves in the direction of opening the valve opening, and the valve body moves from the discharge chamber 32. The amount of refrigerant supplied to the crank chamber 6 increases, and the crank chamber pressure is increased to reduce the swing angle of the swash plate 20 (see FIG. 2).

As shown in FIG. 3, the shaft sealing member 10 and the radial bearing 11 are arranged at intervals in the axial direction, and the shaft is arranged between the inner surface of the boss portion 4a of the front head 4 and the peripheral surface of the drive shaft 7. An annular seal chamber 33 partitioned by the sealing member 10 and the radial bearing 11 is formed. Further, the front head 4 holds a bearing surface that receives the thrust bearing 18 of the inner wall surface 4a located above the drive shaft 7, more specifically, the thrust bearing 18 with the needle roller 18a as shown in the figure. In the case of being configured by the thrust trace 18b, a guide groove 34 for guiding the lubricating oil is extended downward in the portion of the front head 4 that receives the thrust trace 18b.
The guide groove 34 (crank chamber 6) and the seal chamber 33 are connected by an oil supply passage 35 formed in the front head 4 at a predetermined angle with respect to the axis of the drive shaft 7, and this oil supply. The lubricating oil introduced into the guide groove 34 is supplied to the seal chamber 33 via the passage 35.
Here, the oil supply passage 35 is opened directly below the guide groove 34 so that the lubricating oil that descends along the guide groove 34 can be received, and most of the lubricating oil that descends along the guide groove 34. Can be introduced.

By the way, the drive shaft 7 is provided with a discharge passage 40 described below. The release passage 40, the through hole 28a formed in the spacer 28 arranged between the drive shaft 7 and the valve plate, and the orifice hole 2a formed in the valve plate 2 form the crank chamber 6 and the crank chamber 6. An air extraction passage that communicates with the suction chamber 31 is formed.

The discharge passage 40 formed in the drive shaft 7 has a shaft hole 41 formed on the axis of the drive shaft 7 from the rear end to the vicinity of the front end, and is formed in the radial direction in the vicinity of the front end of the drive shaft 7, and one end thereof is a shaft. A first side hole 42 that communicates with the hole 41 and the other end opens into the seal chamber 33 is formed in the radial direction in the middle of the drive shaft 7, one end communicates with the shaft hole 41, and the other end is the crank chamber. It has a second side hole 43 that opens into 6.

As also shown in FIG. 4, the passage cross section (cross-sectional area S1) of the first side hole 42 is formed smaller than the passage cross section (cross-sectional area S2) of the second side hole 43, and in this example, the first side hole 42 The diameter of the shaft hole 42 of 1 is formed to be smaller than half the diameter of the shaft hole 43 of the second shaft hole 43.

Further, the passage cross section (cross-sectional area S1) of the first side hole 42 is set to be substantially equal to the area of the clearance α between the plane bearing as the radial bearing 11 and the drive shaft 7.

In the above configuration, when the compressor rotates at high speed, the oil stored in the crank chamber is scraped up by the swash plate, adheres to the inner surface of the front head (the wall surface of the crank chamber), and flows down along this inner surface. To do. When the oil flowing down along the inner surface reaches the oil supply passage 35 from the guide groove 34, it is sucked by the differential pressure between the crank chamber 6 and the suction chamber 31, so that the seal chamber 33 passes through the oil supply passage 35. Will be actively guided to. The oil introduced into the seal chamber 33 is used to lubricate the sliding contact portion between the shaft sealing member 10 and the rotating drive shaft 7, and then the first oil is generated by the differential pressure between the crank chamber 6 and the suction chamber 31. It is sucked into the shaft hole 41 through the side hole 42 and discharged to the suction chamber 31 through the discharge passage 40 of the drive shaft 7 without staying in the seal chamber 33.

On the other hand, the portion of the drive shaft 7 exposed to the crank chamber 6, that is, the periphery of the second side hole 43, is in an oil-poor state in which the oil is repelled to the outer peripheral side by the rotation of the swash plate 20. In addition, the inflow of oil is suppressed through the second side hole 43 by the centrifugal force due to the rotation of the drive shaft 7, but the refrigerant gas in the crank chamber is released due to the differential pressure between the crank chamber 6 and the suction chamber 31. It flows into the shaft hole 41 through the second side hole 43 and is discharged to the suction chamber 3.

Therefore, the oil discharged into the suction chamber 31 through the shaft hole 41 is introduced into the shaft hole 41 only through the first side hole 42, and the refrigerant gas released into the suction chamber 31 is mainly the second second side hole 42. It will be introduced into the shaft hole 41 via the side hole 43. Therefore, since the shaft hole 41 of the drive shaft 7 is used as both a refrigerant gas discharge passage and an oil discharge passage, the oil guided to the shaft hole 41 through the first side hole 42 is a second. Compared with the case where the side hole 43 does not exist or the second side hole 43 is closed, the amount is relatively small, and the oil in the crank chamber is not excessively discharged.

After that, the rotation speed decreases from this state to idle operation, and from the state shown in FIG. 2, the air supply passage is closed by the pressure control valve in order to maximize the discharge capacity, and the working fluid is transferred from the discharge chamber 32 to the crank chamber 6. Even when the supply is stopped, the oil is retained in the crank chamber 6, so that it is possible to maintain good lubrication inside the compressor.

The inventors conducted a durability test using the following specimens, and found out the temperature of the shaft sealing member 10, the presence or absence of sludge at the sliding contact point between the shaft sealing member 10 and the drive shaft 7, and the radial bearing (plane). When the state of wear and peeling of the sliding layer of the bearing) 11 was measured, the results shown in Table 1 below were obtained.
<Sample>
-Diameter of the first side hole 42: (1) None, (2) 0.8 mm, (3) 1.5 mm, (4) 2.0 mm
-Diameter of the second side hole 43: 4.0 mm
-Diameter of shaft hole 41: 6.0 mm
-Diameter of orifice hole 2a: 1.5 mm
<Durability test conditions>
Rotation speed: 9000r / min
Discharge pressure / suction pressure: 1.5 MPa / 0.23 MPa
Evaporator load: 9 kW
Operation mode: Intermittent operation (on / off: 20 seconds / 10 seconds)
Endurance time: 180 hours

As can be seen from this result, when the first side hole 42 is not provided, the temperature of the shaft sealing member 10 (the temperature of the sealing chamber 33) becomes relatively high and comes into sliding contact with the shaft sealing member 10 of the drive shaft 10. The generation of sludge was confirmed at the site. Therefore, the sealing function is impaired, which may lead to oil leakage.

On the other hand, in all of the cases provided with the first side hole 42, the temperature of the shaft sealing member 10 dropped by about 10 degrees, and no sludge was observed. From this, it was confirmed that by further providing the first side hole 42 in addition to the second side hole 43, the shaft sealing member 10 is cooled and oil leakage is effectively suppressed.

However, in the specimen (4) in which the diameter of the first side hole 42 was φ2, wear of the sliding layer of the plain bearing was confirmed. Here, focusing on the relationship between the area of the clearance between the radial bearing (plain bearing) 11 and the drive shaft 7 and the area of the first side hole 43, the radial bearing (plain bearing) 11 and the drive shaft The area of the clearance between 7 and 7 is about 1.5 mm ² , while the cross-sectional areas of the first side holes are (2) 0.5 mm ² , (3) 1.5 mm ² , and (4), respectively. It becomes 3.1 mm ² , and in (4), the area of the first side hole 42 is larger than the area of the clearance α between the radial bearing (plain bearing) 11 and the drive shaft 7. From this, when the diameter of the first side hole 42 becomes larger than the diameter corresponding to the area of the clearance α between the radial bearing (plain bearing) 11 and the drive shaft 7, the oil held in the seal chamber 33 is released. It is considered that the amount of oil is reduced and the oil is not sufficiently distributed in the clearance α between the radial bearing (plain bearing) 11 and the drive shaft 7.

Therefore, since it is necessary to hold the oil in the crank chamber 6 regardless of the rotation speed, even when the second side hole 43 that always communicates with the crank chamber 6 is provided, the temperature rise due to the sliding heat generation of the shaft sealing member 10 is prevented. It is necessary to increase the fluidity of the oil in the seal chamber 33, and in order to meet the demand, it is better to increase the diameter of the first side hole 42, but due to the decrease in the oil held in the seal chamber 33. In order to avoid wear of the radial bearing (plain bearing) 11, it is necessary to avoid making the diameter of the first side hole 42 too large. Therefore, in the above example, in order to achieve both of these, the area of the first side hole 42 is set to the area of the clearance between the radial bearing (plain bearing) 11 and the drive shaft (about 1.5 mm ² ). It is desirable to keep the same level (1.5 mm ^{2 in} the case of φ1.4 mm) to ensure the lubricity of the radial bearing (plain bearing) 11 while ensuring the fluidity of the oil in the seal chamber 33 to prevent wear.

In the above test, as shown in FIG. 5, the first side hole 42 of the drive shaft 7 is substantially the same as the phase position of the link mechanism 19 that connects the swash plate 20 and the thrust flange 17. It is arranged at the phase position in the rotation direction. That is, based on the circumferential position corresponding to the bottom dead center of the piston 15 of the drive shaft 7, the phase angle θ in the rotation direction of the first side hole 42 is the circumferential position corresponding to the top dead center of the piston. It is almost the same as the phase angle (180 °).

Next, the inventors have different phase angles θ of the first side hole 42 with reference to the circumferential position of the drive shaft 7 corresponding to the bottom dead center of the piston ((1) to (1) to ( When a durability test was performed using 5)) and the time until leakage was detected from the shaft sealing member 10, the results shown in Table 2 below were obtained.
<Sample>
Opening position of the first side hole 42: As shown in FIG. 6, the phase angle θ is set as follows from the circumferential position of the drive shaft 7 corresponding to the bottom dead center toward the advance direction of the drive shaft 7. Five different specimens were prepared.
・ 15 °
・ 80 °
・ 130 °
・ 215 °
・ 245 °
-Opening position of the second side hole 43: in phase with the first side hole 42-Diameter of the first side hole 42: 1.5 mm
-Diameter of the second side hole 43: 4.0 mm
-Diameter of shaft hole 41: 6.0 mm
-Diameter of orifice hole 2a: 1.5 mm
<Durability test conditions>
Operation mode: Off mode endurance test + low temperature luck endurance test + combined operation endurance test

From this result, when the first side hole 42 is viewed from the front side, the specimens (3), (4), and (5) provided in the first quadrant and the second quadrant leak up to about 1000 hours. Not detected, especially the specimens (3) and (4) show high durability.
In the variable swash plate compressor during operation, the compression reaction force of the piston 15 acts on the drive shaft 7 via the swash plate 20, the link mechanism 19, and the thrust flange 17, and this force acts on the thrust bearing 18 and the radial bearing. (Plain bearing) 11 is supported. That is, as shown by the arrow in FIG. 6, the drive shaft 7 presses a predetermined position of the radial bearing 11.

Here, when the force received from the drive shaft 7 by the radial bearing 11 on the front side in the vicinity of the shaft sealing member 10 is analyzed, the drive shaft 7 is supported by the bearing 11 in the second quadrant when viewed from the front. At the position indicated by the arrow, the drive shaft 7 presses the radial bearing 11), and a clearance C is generated between the radial bearing 11 and the drive shaft 7 in the fourth quadrant on the opposite side (the figure is for understanding). Therefore, it is exaggerated.) The seal chamber 33 and the crank chamber 6 communicate with each other through the clearance C, and the oil and gas in the crank chamber 6 are also guided to the seal chamber 33 through the clearance C. Then, the oil or gas guided to the seal chamber 33 is sucked into the suction chamber 31 from the shaft hole 41 through the first side hole 42.

In the specimens (3) and (4), as shown in FIG. 7, the phase position in the rotation direction in which the first side hole 42 is provided is the sliding of the drive shaft 7 and the radial bearing 11. It is located on the front side (within ± 50 °) of the contact point S in the rotation direction. For this reason, since the gas and oil are sucked through the first side hole 42, the oil and gas are likely to concentrate in the portion close to the first side hole 42, and are guided to the clearance C on the front side in the rotation direction. The oil is easily guided to the sliding portion S between the drive shaft 7 and the radial bearing 11 as the drive shaft 7 rotates. It is considered that this suppresses heat generation at the sliding contact portion S of the radial bearing 11, the temperature around the shaft sealing member becomes relatively low, and the generation of sludge due to the high temperature is suppressed.

On the other hand, in the specimens (1) and (2), the distance from the phase position where the first side hole 42 is provided to the sliding contact portion S between the drive shaft 7 and the radial bearing 11 is Since they are separated from each other, the oil in the gas sucked from the crank chamber 6 through the clearance C is sucked into the first side hole 42 before staying on the bearing surface. As a result, the oil guided to the clearance C is not sufficiently guided to the sliding portion S between the drive shaft 7 and the radial bearing 11, the lubrication of the sliding contact portion S becomes insufficient, and heat is generated in the sliding contact portion S. As a result, it is probable that the temperature around the shaft sealing member became relatively high, causing sludge to occur and causing oil leakage.

Therefore, from the result of the durability test, the first side hole 42 is on the side where the link mechanism 19 is provided with respect to the shaft hole 41 of the drive shaft 7, that is, the axis of the drive shaft 7 and the link mechanism 19. A plane orthogonal to the plane α including the center (shown in FIG. 5), and the side on which the link mechanism 19 is provided with the plane β (shown in FIG. 5) including the axis of the drive shaft 7 as a boundary. It is preferable to provide the link mechanism 19 in a range of ± 50 ° with respect to the phase position in the rotation direction of the link mechanism 19.

1 Cylinder block 2 Valve plate 3 Rear head 4 Front head 6 Crank chamber 7 Drive shaft 10 Shaft sealing member 11, 12 Radial bearing 26 Air supply passage 27 Pressure control valve 31 Suction chamber 32 Discharge chamber 33 Seal chamber 35 Oil supply passage 40 Discharge passage 41 Shaft hole 42 First side hole 43 Second side hole

Claims (6)

A housing in which a crank chamber is defined and a suction chamber and a discharge chamber are formed,
A drive shaft that rotatably supports the housing through the crank chamber via a radial bearing and one end of which protrudes from the housing.
A swash plate housed in the crank chamber and rotating in synchronization with the rotation of the drive shaft,
A shaft sealing member arranged on one end side of the drive shaft with respect to the radial bearing and sealing between the drive shaft and the housing.
An oil supply passage formed in the housing, one end communicating with the crank chamber and the other end communicating with the seal chamber formed between the radial bearing and the shaft sealing member.
In order to control the pressure in the crank chamber and control the inclination angle of the swash plate with respect to the drive shaft, the air supply passage communicating the discharge chamber and the crank chamber and the opening degree of the air supply passage are adjusted. In a variable displacement swash plate compressor with a pressure control valve
On the drive shaft
A shaft hole that communicates with the suction chamber and extends axially from the rear end to the front end of the drive shaft.
A first side hole extending in the radial direction and always communicating the seal chamber and the shaft hole,
A second side hole extending in the radial direction and always communicating the crank chamber and the shaft hole,
A variable-capacity swash plate compressor characterized by the provision of. The variable displacement swash plate compressor according to claim 1, wherein the passage cross section of the first side hole is smaller than the passage cross section of the second side hole. The variable capacitance swash plate compressor according to claim 1 or 2, wherein the radial bearing is a plain bearing. The variable capacitance swash plate compressor according to claim 3, wherein the passage area of the first side hole is substantially equal to the area of the clearance between the plain bearing and the drive shaft. A thrust flange fixed to the drive shaft and rotatably supported with respect to the inner wall surface of the housing is connected to the swash plate via a link mechanism.
The variable capacitance according to any one of claims 1 to 4, wherein the first side hole is provided on the side of the drive shaft on which the link mechanism is provided with respect to the shaft hole. Slanted plate compressor. The variable capacitance swash plate compressor according to claim 5, wherein the first side hole is provided in a range of ± 50 ° with respect to a phase position in the rotation direction of the link mechanism.

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