JP2715558B2 - Swash plate type variable capacity compressor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swash plate type variable displacement compressor used for compressing and discharging a refrigerant in an automotive air conditioner, for example.

[Background Art] In a swash plate compressor, a swash plate is attached to a shaft introduced into a swash plate chamber so as to be integrally rotated, and an outer peripheral portion of the swash plate is rotated by the rotation of the shaft. It is made to swing in parallel to the axial direction. The swash plate reciprocates, for example, a double-headed piston so that the refrigerant is sucked in and compressed and discharged.

In this case, by the variable member that displaces the axial position of the shaft, while displacing the mounting position of the rotation center position of the swash plate with respect to the shaft, changing the inclination angle of the swash plate,
A variable mechanism for continuously changing the displacement of the compressor has been considered.

In such a compressor, lubricating oil is set particularly in a swash plate chamber having many sliding mechanisms, so that the lubricating oil is circulated together with the operation of the compressor. However, when the inclination angle of the swash plate with respect to the shaft is close to a right angle and the operating stroke of the piston is reduced and the discharge capacity is reduced, the amount of oil in the return refrigerant contained in the intake gas decreases. In addition, the amount of lubricating oil circulating in the swash plate chamber is reduced, and there is a concern that the lubricating oil is insufficient and the durability of the sliding mechanism is reduced.

[Problems to be Solved by the Invention] The present invention has been made in view of the above points, and particularly in a state where a small capacity operation is performed, a large number of sliding mechanisms are set, and especially a lubricating oil is provided in a swash plate chamber. Is satisfactorily circulated to provide a swash plate type variable displacement compressor in which durability and reliability are surely improved.

Means for Solving the Problems In the swash plate type variable displacement compressor according to the present invention, a piston is driven by a swash plate that is rotated with rotation of a shaft, and the piston sucks, for example, a refrigerant. ,
In a compressor configured to perform a compression discharge and a refrigerant discharge capacity is continuously varied in accordance with an inclination angle of the swash plate, the compressor is connected to a discharge chamber to which the refrigerant discharged from the piston is supplied. Forming an oil separation chamber, and forming a passage between the oil separation chamber and the swash plate chamber in which the swash plate is set, and opening and closing in accordance with a control pressure or an operating pressure determined by a discharge pressure specified in the passage. A control valve is provided.

[Operation] In the swash plate type variable displacement compressor configured as described above, for example, the mounting position of the swash plate with respect to the shaft and the inclination angle of the swash plate with respect to the shaft are variably controlled corresponding to the control pressure. The operation stroke of the piston is varied, and the displacement is continuously changed. In this case, when the discharge capacity is large, the amount of lubricating oil contained in the return refrigerant is large, and the sliding mechanism in the swash plate chamber is well lubricated. However, when the discharge capacity is small, the amounts of the returning refrigerant and oil are small, and the amount of oil circulated through the sliding mechanism decreases. In this state, by opening the control valve by the difference between the operating pressure and the swash plate chamber pressure, a passage is formed between the oil reservoir and the swash plate in the oil separation chamber, and the oil in the oil reservoir is transferred to the swash plate chamber. It is sent, agitated by the swash plate, and supplied to the sliding portion.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional structure of a swash plate type compressor. This compressor is used as a refrigerant compression device in, for example, an automotive air conditioner, and the compressed refrigerant is discharged and expanded. The refrigerant is returned and drawn.

This compressor includes a cylinder housing 11 which is made of aluminum alloy and has a cylindrical shape. Inside the cylinder housing 11, for example, five cylinder chambers 12 are provided in parallel at five locations along an outer peripheral portion thereof. (Only one portion is shown in the figure). Each cylinder chamber 12 has a front cylinder 12
1 and the rear cylinder 122 are formed coaxially.

A shaft 13 is set on a central shaft portion of the cylinder housing 11, and the shaft 13 is rotatably supported by bearings 14 and 15.
Here, a cylindrical support member 16 is set on the outer peripheral portion of the shaft 13 so as to be movable in the longitudinal direction of the shaft 13, that is, in the axial direction. A bearing 15 is provided on the outer peripheral portion of the support member 16. Set, this bearing 15 is the shaft 13
To be supported by the spool 17.

The spool 17 is supported movably in the axial direction inside a cylindrical body 18 formed so as to surround a central shaft portion of the cylinder housing 11.

The thrust force acting on the shaft 13 is made to be supported by the thrust bearings 19 and 20. The thrust bearing 20 is interposed between the support step 21 formed on the support member 16 and the end face of the spool 17, and the thrust bearing 19 is formed on the engagement step 22 formed on the shaft 13 and the housing 11. It is sandwiched between the locking shoulder 23.

The interior of the housing 11 is a swash plate chamber 24, and a spherical rotating support 25 is formed integrally with the support member 16 in the swash plate chamber 24. Plate 26
Is set so as to be fitted, and the swash plate 26 is tilted about the rotation support 25 so as to rotate integrally with the shaft 13. That is, when the shaft 13 is rotated, the swash plate 26 attached in a state inclined with respect to the axis of the shaft 13 is rotated in this inclined state, and the outer peripheral edge of the swash plate 26 is aligned with the axis of the shaft 13. It comes to swing in parallel. In this case, the swing range is determined by the inclination angle of the swash plate 26, and the larger the inclination angle, the larger the swing range.

Here, a pin 27 is formed integrally with the swash plate 26, and the pin 27 is formed in a link groove 28 formed in the shaft 13.
When the swash plate 26 is displaced so as to move in the axial direction of the shaft 13 together with the rotary support 25, the inclination angle of the swash plate 26 with respect to the shaft 13 is changed.

A spring 29 is interposed between the support member 16 on which the rotary support 25 is set and the shaft 13, so that a force for moving the support member 16 in a direction away from the link groove 28 is set. This force is received by a control piston 30 provided integrally with the spool 17. That is, by displacing the control piston 30, the support member 16 is moved, the support center position of the swash plate 26 is displaced, and the pin 27 is moved along the link groove 28, so that the inclination of the swash plate 26 The angle becomes variable. Specifically, when the control piston 30 is displaced away from the link groove 28, the support member 16 is displaced in the same direction as the control piston 30 by the force of the spring 29, displacing the position of the swash plate 26, and , To lean greatly.

A shoe 31 is formed integrally with the outer peripheral edge of the swash plate 26, and the pistons 311 and 312 are connected with the shoe 31. Here, the shoe 31 is formed in a spherical shape, and the pistons 311 and 312 are linearly reciprocated in the front and rear cylinders 121 and 122 by rotating and swinging the swash plate 26 together with the shaft 13. You.

The pistons 311 and 312 form working chambers in the cylinders 121 and 122, respectively, and the working chambers communicate with suction chambers 331 and 332 via suction ports 321 and 322, respectively. The working chamber of each of the cylinders 121 and 122 is connected to the discharge chamber 35 through discharge ports 341 and 342, respectively.
Communicated with 1 and 352. Although not shown in detail, the working chamber side of the suction ports 321 and 322, and the discharge port 341
A suction valve and a discharge valve are arranged and arranged on the discharge chamber 351 and 352 sides of the suction chamber 342 and the suction chamber 342, respectively, so that only the suction medium and the discharge medium pass therethrough.

Here, the suction ports 321 and 322 and the discharge ports 341 and 342 are formed in the side plates 36 and 37, and the side plates 36 and 37 are held on the front side and the rear side of the housing 11, respectively. , A front housing 38 and a rear housing 39 are set, and are assembled integrally with the housing 11 by through bolts 40 as appropriate. The suction port 321 and the discharge port 341 are formed in the front housing 38, and the suction port 322 and the discharge port 341 are formed in the rear housing 39.

The suction chamber 332 is configured to be partitioned by the control piston 30 in the rear housing 39, and the control pressure chamber 41 in which the back pressure of the control piston 30 is set.
Is set to a control pressure. This control pressure is applied to the suction chamber 332
And the discharge pressure set in the discharge chamber 352 are mixed and controlled by a control valve (not shown).

Here, the control piston 30 is pushed in the direction of the shaft 13 by the spring 42, and its position is set to be displaced in accordance with the pressure difference between the control pressure and the suction pressure.

An oil separation chamber 43 is formed adjacent to the rear discharge chamber 352. That is, the discharge gas is put together through the opening formed in the partition wall of the discharge chamber 352, and a flow is directed toward the inner wall of the rear housing 39, which is the side wall of the oil separation chamber 43,
Oil in the refrigerant gas is attached to the wall by inertia,
The oil separating chamber 43 is configured to be collected at the bottom by gravity. 431 is accumulated oil.

A passage 44 is formed between the bottom of the oil separation chamber 43 and the swash plate chamber 24, and an oil return valve 45 is interposed in the passage 44. 431 is collected in the swash plate chamber 24.

FIG. 2 shows the oil return valve 45, in which a ball valve 452 is set so as to be supported by a spring 451.
The oil passage 44 is closed by setting it to the left side in the drawing against the 451. In this case, an operating pressure is applied to the spool valve 453 as a back pressure, and the spool valve 453 is driven by a differential pressure between the operating pressure and a set pressure set in the swash plate chamber 24. In particular,
In the state where the operating pressure is larger than the sum of the set pressure and the biasing force of the spring 451, the passage 44 is closed as shown in FIG. As a result, the ball valve 452 is opened, the passage 44 is opened, and the accumulated oil 431 is led to the swash plate chamber 24.

Here, the operating pressure is set by the control pressure set in the control pressure chamber 41, and the capacity of the compressor is low, that is, the angle of the swash plate 26 at which the strokes of the pistons 311 and 312 are small is set. In this state, the control pressure is low. Therefore, the oil return valve 45 is in the state shown in FIG. 2 (B).
431 can be sent to the swash plate room 24.

The oil fed into the swash plate chamber 24 is agitated by the rotation of the swash plate 26, and is sent to sliding portions of each part in the swash plate chamber 24 to be provided for lubrication.

The swash plate type variable displacement compressor has a swash plate chamber 24
When the swash plate chamber 24 is used as an oil storage chamber, the oil storage chamber 46 of the swash plate chamber 24 is separated from the suction gas passage.
, The lubrication of the swash plate 26 and the shoe 31 is further improved.

If the amount of the accumulated oil 431 is large, the discharged gas may flow backward. For this purpose, it is effective to provide a throttle in the passage 44.

When the swash plate chamber 24 is configured to be isolated from the suction gas passage, the pressure in the swash plate chamber 24 also increases during refueling, and the differential pressure between the swash plate chamber and the suction pressure chamber increases. In this type of compressor, the oil in the swash plate chamber can be sent to each sliding portion by using the differential pressure.

FIG. 3 shows another example of a simplified type of the oil return valve 45. In this example, the discharge pressure is used as the control pressure. Compressor capacity does not change with discharge pressure, but during high heat load when a large capacity is required for the compressor, the high pressure on the discharge side generally rises, and when low heat load does not require a large capacity for the compressor. The high pressure on the discharge side does not increase very much, and therefore, by using the discharge pressure, the compressor capacity can be determined though indirectly. The same components as those in FIG. 2 are denoted by the same reference numerals. In this example, throttles 471 and 472 are formed in the discharge pressure supply passage and the passage 44 to the swash plate chamber 24, respectively.

Here, it is desirable that the return oil amount returns almost all of the oil separated in the oil separation chamber 43. Because, the oil collected at the bottom of the oil separation chamber 43 is
This is because dead oil does not contribute to lubrication. However, in order to return all the oil in the oil separation chamber 43, the diameter of the passage must be increased. However, when the passage diameter is increased, a part of the discharge or refrigerant gas is bypassed to the suction side, and the performance and efficiency of the compressor are significantly reduced. For this reason, the return oil passage is
0.3-0.5mm in diameter to ensure the processed surface and oil return
It is desirable to have a passage area equivalent to the extent. The height of the outlet of the oil passage 44 on the swash plate chamber 24 side is desirably set to the position of the sliding portion of the shoe 31 and the swash plate 26, which have the most slidable sliding conditions in the swash plate chamber compressor.

Here, it is desirable that the set value of the operating pressure at which the oil return valve 45 is controlled is set such that the oil is controlled to return when the capacity of the compressor becomes approximately 1/3. . The actual value is the shape of the link groove 28 (determines the variable characteristics of the relationship between control pressure and compressor capacity).
For example, the differential pressure between the control pressure and the pressure in the swash plate chamber 24 is set to about 3 kg / cm ² .

In the embodiment shown in FIG. 1, the configuration in which the swash plate chamber is separated from the suction gas passage is shown. However, in the configuration in which the swash plate chamber is separated from the suction gas passage, more advantageous effects are obtained. It is thought that it can be a thing. In other words, in the compressor having the separated structure, the swash plate chamber is only connected to the suction side by the narrowed pressure equalizing hole, and even if the discharged gas returns together with the oil, This is because a sharp decrease in performance can be prevented.

FIG. 4 shows another embodiment, and the same components as those in the embodiment shown in FIG.

In this embodiment, a first oil passage 50 is formed between the swash plate chamber 24 of the cylinder housing 11 and the outer peripheral surface of the spool 17 of the control piston 30. A second oil passage 51 which is opened close to the opening and communicates with the pool oil 431 of the oil separation chamber 43 is formed. A groove is formed on the outer peripheral surface of the spool 17.
52, the spool 17 moves in the axial direction together with the control piston 30, so that the first and second passages 51 and 50 are communicated with each other, and the accumulated oil 431 flows into the swash plate chamber 24 via the passages 51 and 50. To be returned.

Specifically, when the compressor capacity is between 1/3 and the maximum capacity, as shown in FIG.
And the accumulated oil 431 is not returned to the swash plate chamber 24. However, at the position of the control piston 30 when the capacity of the compressor is about 1/3 or less as shown in FIG. 3B, the passages 50 and 51 communicate with each other through the groove 52, and the accumulated oil 431 passes through the passage. It is sent to the groove 52 via 51 and further returned to the swash plate chamber 24 via the passage 50.

In this case, the diameter of the oil passages 50 and 51 may be reduced in order to reduce the return oil amount.
In addition, the aperture function may be set by setting the depth dimension of the groove 52 to be small. If the depth dimension of the groove 52 is set to be small, the effect on foreign matters is reduced. It is a target.

In the embodiment shown so far, the passage 50 is directly opened to the swash plate chamber 24, and the accumulated oil 431 is lubricated to the swash plate 26, the shoe 31, and the like after the oil is once returned to the swash plate chamber 24. However, the passage 50 may be opened to a lubricated portion such as a bearing as needed. In this case, the accumulated oil 431 is first supplied to the swash plate chamber 24 after the bearing portion is lubricated, and then the shoes 31 and the like are lubricated.

[Effects of the Invention] As described above, according to the swash plate type variable displacement compressor according to the present invention, the return oil control is performed so that sufficient lubricating oil can be sufficiently distributed to the sliding portion particularly when the compressor is operated with a small capacity. As a result, the compressor is durable and the reliability thereof is made sufficient. For example, the compressor can be made highly reliable as a refrigerant compressor of an air conditioner for an automobile.

[Brief description of the drawings]

FIG. 1 is a sectional view for explaining a swash plate type variable displacement compressor according to one embodiment of the present invention, and FIGS. 2A and 2B show states of an oil return valve in the above embodiment, respectively. FIG. 3, FIG. 3 is a diagram showing another example of the oil return valve, FIG. 4 is a sectional configuration diagram for explaining another embodiment of the present invention, and FIGS. It is a figure explaining the state of the return oil passage of the above-mentioned example. 11 …… Cylinder housing, 12 …… Cylinder chamber, 13 ……
Shaft, 17 Spool, 24 Swash plate chamber, 26 Swash plate, 30 Control piston, 31 Shoe, 311, 312
Piston, 321, 322 …… Suction port, 331, 332 …… Suction chamber,
341, 342 ... discharge port, 351, 352 ... discharge chamber, 41 ... control pressure chamber, 43 ... oil separation chamber, 431 ... pooled oil, 45
...... Oil return valve.

Claims (1)

(57) [Claims] 1. A housing in which a shaft is set to penetrate and in which a cylinder chamber and a swash plate chamber are set, and wherein the shaft is mounted and set on the shaft so that a tilt angle is variable, and is set in the swash plate chamber. A swash plate that is oscillated and rotated with the rotation of a swash plate; and a piston that is set to be capable of linear movement in a cylinder chamber that is set in the swash plate chamber, and that is reciprocated by the swing of the swash plate with the rotation of the front shaft A mechanism for displacing a rotation center of the swash plate with respect to the shaft in an axial direction of the shaft based on a control pressure, changing an inclination angle of the swash plate, and continuously changing a discharge capacity by the piston mechanism. A capacity variable mechanism, and an oil separation chamber formed continuously with a discharge chamber to which compressed refrigerant and oil discharged by the operation of the piston mechanism are supplied. A control valve formed in a passage communicating the oil separation chamber and the swash plate chamber with an operating pressure consisting of the control pressure or the discharge pressure and a differential pressure between the swash plate chamber pressure and the control valve. A swash plate type variable displacement compressor wherein oil is introduced into the swash plate chamber in a state where the differential pressure between the operating pressure or the discharge pressure and the swash plate chamber pressure is reduced.