JPH0540303Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a variable displacement swash plate compressor equipped with a double-ended piston.

[Prior Art] In a double-headed piston type compressor disclosed in Japanese Patent Application Laid-Open No. 58-162782, a swash plate is supported so as to be rotatable integrally with a rotating shaft and swingable back and forth. The inclination angle of the air conditioner is controlled based on suction pressure information that reflects the cooling load. However, since the center of oscillation of the swash plate is set at a fixed position on the rotation axis, the top dead center of the compression stroke of the double-headed piston fluctuates depending on the inclination angle of the swash plate in both the front and rear compression chambers. Substantial compression and discharge cannot be performed in the compression action area on the small volume side where the inclination angle is close to zero.

The applicant of the present application has filed Japanese Patent Application No. 62-298630 for a compressor that improves this drawback. The center of oscillation of the swash plate in this compressor is set at the radial position of the rotating shaft that corresponds to the cylinder bore of the cylinder block that houses the double-headed piston. is defined at a fixed position, and substantial compression and discharge are performed even in the compression action area on the small capacity side where the swash plate inclination angle is close to zero.

The inclination angle of the swash plate is determined by the swash plate rocking force due to the pressure in both the front and rear cylinder bores, and the pressure in the control pressure chamber defined by intervening a sliding control body in the suction chamber on the cylinder bore side at the fixed position of the top dead center of the compression stroke. It fluctuates depending on the difference between A control pressure chamber for controlling the swash plate inclination angle is connected to a discharge pressure region and a suction pressure region, and a capacity control valve mechanism interposed on this connecting passage controls refrigerant flow from the control pressure chamber side to the suction pressure region side. Both or one of the gas flow rate and the refrigerant gas flow rate from the discharge pressure region side to the control pressure chamber is controlled, and the pressure in the control pressure chamber is controlled by controlling the flow rate. The swinging of the swash plate is supported by the spherical part of a guide bushing that is slidably fitted onto the rotating shaft and rotates integrally with the shaft. A dynamic control body is fitted and supported via a radial bearing.

[Problem to be solved by the invention] The sliding control body, which is urged in the direction of increasing the tilt angle by the control pressure in the control pressure chamber, is received by a guide bushing via a thrust bearing. Due to the mechanism, the radial bearing is blocked from the area where the refrigerant gas exists by the sliding control body and the race.
In such a closed configuration, mist-like lubricating oil in the refrigerant gas cannot be supplied to the friction parts of the radial bearing, and early wear of the radial bearing is unavoidable.

The object of the present invention is to provide a variable capacity swash plate compressor that can avoid early functional deterioration of the radial bearing by supplying refrigerant gas to the friction area of the radial bearing between the guide bush and the sliding control body. It is something to do.

[Means for Solving the Problems] To achieve this, in the present invention, a guide bush that supports the rocking of the swash plate is slidably fitted and supported on the rotating shaft, and a guide bush is provided in the suction chamber partitioned from the rear cylinder bore by a partition plate. A control pressure chamber for capacity control is provided, and a sliding control body that changes the volume of the control pressure chamber is inserted through the partition plate and the cylinder block and fitted onto the outer periphery of the guide bushing via a radial bearing. A passage was provided through the slide control body to communicate the gap between the slide control body and the suction pressure region and to supply refrigerant gas to the gap.

[Operation] Refrigerant gas in the suction pressure region enters the gap between the guide bush and the sliding control body through the supply passage, and reaches the friction site of the radial bearing interposed in the gap. As a result, mist-like lubricating oil in the refrigerant gas is supplied to the friction areas of the radial bearing, thereby avoiding premature wear of the radial bearing.

[Example] Examples 1 to 3 that embody the present invention will be described below.
This will be explained based on the diagram.

A front housing 2 and a rear housing 3 are fitted and fixed to both front and rear end surfaces of the cylinder block 1, and a rotating shaft 4 is rotatably supported by the front housing 2 and the cylinder block 1 via a front shaft portion 4a. There is. Front shaft portion 4a
A rear shaft portion 4b is connected and fixed to the inner end side of the rear shaft portion 4b via connecting bodies 5 and 6, and guide holes 5a and 6a are formed in the connecting bodies 5 and 6. The guide bush 7 is slidably fitted, and a pressure spring 8 is interposed between the tip of the rear shaft portion 4b and the inner end of the guide bush 7.

There are shaft pins 7 on the left and right sides of the base end of the guide bush 7.
a (only one shown) is provided protrudingly, and the shaft pin 7
A swash plate 9 is rotatably supported on a. A bridge 9a is formed on the front surface of the swash plate 9, and a guide pin 9b is fitted in the middle of the bridge so as to protrude to both sides, and a rotor 9c is attached to both ends of the guide pin 9b. installed. The bridge 9a is inserted between both the connecting bodies 5 and 6, and the rotor 9c is inserted into the guide hole 5 of the connecting bodies 5 and 6.
a, 6a, thereby causing the swash plate 9 to rotate together with the rotating shaft 4 within the swash plate chamber 1a. The rotating shaft 4, the swash plate 9, and the guide bush 7 are connected to each other through a guiding relationship between the guide pin 9b and the guide holes 5a, 6a, and a rotatable relationship between the swash plate 9 and the guide bush 7, which is slidable back and forth. As a result, the swash plate 9 can swing as the guide bush 7 slides, and the center of swing C is set at the periphery of the swash plate 9.

A plurality of cylinder bores 1b and 1c (five each in this embodiment) are formed on the front and rear sides of the cylinder block 1 so as to correspond to each other on the rotation locus of the swash plate 9. Suction passages 1d, 1e, and 1e' are formed between the rear cylinder bore 1c, and a double-headed piston 10 is housed in the corresponding front cylinder bore 1b and rear cylinder bore 1c. Each double-ended piston 10 and swash plate 9 are
1 and 12, and the double-ended piston 1
0 reciprocates back and forth as the swash plate 9 rotates.

Cylinder block 1 and both front and rear housings 2, 3
A partitioning plate 13, 14 and a valve forming plate 15, 16 are interposed between the two housings, and suction chambers 17, 18 and discharge chambers 19, 20 are defined in both the front and rear housings 2, 3. The front suction chamber 17 communicates with the swash plate chamber 1a via the suction passage 1d, and also communicates with the front partition plate 1.
It is connected to the front side compression chamber Pf between the front side partition plate 13 and the double-headed piston 10 via the suction hole 13a on the front side partition plate 13 and the suction valve 15a on the front side valve forming plate 15. The front side discharge chamber 19 is connected to the front side compression chamber via the discharge hole 13b on the front side partition plate 13 and the discharge valve 28.
Connected to Pf. Similarly, the rear suction chamber 18
are connected to the swash plate chamber 1a through suction passages 1e and 1e', and are connected to the rear through suction holes 14a and 14a' on the rear partition plate 14 and suction valves 16a on the rear valve forming plate 16. Rear side compression chamber between side partition plate 14 and double-ended piston 10
Connected to Pr. The rear discharge chamber 20 has a discharge hole 14b on the rear partition plate 14 and a discharge valve 2.
It is connected to the rear side compression chamber Pr via 9.

The refrigerant gas in the suction pipe line 21 constituting the external refrigerant gas circuit enters the swash plate chamber 1a from the inlet 22 as the double-headed piston 10 reciprocates, and enters the front side suction passage 1d, the rear side suction passages 1e, 1e', and the front side suction passage 1d. The air is sucked into the front compression chamber Pf and the rear compression chamber Pr through the side suction chamber 17 and the rear suction chamber 18, and is subjected to a compression action. And the front side compression chamber
The refrigerant gas discharged from Pf to the front discharge chamber 19 flows out to the discharge passage 1f, passes through the discharge passage 1f, is discharged from the outlet 23, and is discharged from the rear compression chamber.
The refrigerant gas discharged from Pr to the rear discharge chamber 20 is discharged from the outlet 23 via the discharge passage 1f.
The swing center C of the swash plate 9 is set on the peripheral edge side of the swash plate 9, and is also set closer to the rear cylinder bore 1c, so that the front compression chamber Pf
The top dead center of the compression stroke of the double-headed piston 10 varies depending on the inclination angle of the swash plate 9, but the compression stroke top dead center of the double-headed piston 10 in
The compression stroke top dead center of the double-headed piston 10 at Pr is defined at the fixed position shown in FIG.

A spool-shaped sliding control body 24 is fitted into the rear suction chamber 18 so as to be slidable in the longitudinal direction, and a part of the rear suction chamber 18 is divided into a control pressure chamber 18a by a flange portion 24a. ing. In the through hole 1g connecting the swash plate chamber 1a and the rear suction chamber 18, a cylindrical portion 24b of the sliding control body 24 is supported via a thrust bearing 25 and a radial bearing 26 to be rotatable relative to the guide bush 7. In addition, a race 31 is interposed between the tip of the guide bush 7 and the thrust bearing 25, and a race 31 is interposed between the guide bush 7 and the cylindrical portion 24b.
A slight gap S is provided between the two. As a result, the pressure inside the control pressure chamber 18a is reduced to the sliding control body 2.
4. The radial bearing 26 opposes the swash plate rocking force generated by the pressure in the front side compression chamber Pf and the pressure in the rear side compression chamber Pr via the guide bush 7 and the swash plate 9, and the radial bearing 26
The control pressure inside the control pressure chamber 18a is received through the control pressure chamber 18a.

A cylindrical screw fastening member 27 is fitted in a stepped through hole 1g of the cylinder block 1 that accommodates the cylindrical portion 24b of the sliding control body 24 so as to be slidable relative to the rotating shaft 4. A nut 30 is screwed onto a threaded portion of a screw fastening member 27 that is fitted from the plate chamber 1a side and projects into the rear suction chamber 18 as shown in FIG. By tightening this nut 30, the flange portion 2 of the screw tightening member 27
7a is pressed against the step of the through hole 1g, and the nut 30 is pressed against the inner circumferential edge of the rear partition plate 14 surrounding the cylindrical portion 24b of the sliding control body 24. As a result, the cylinder block 1 and the partition plate 14 are separated from each other around the cylindrical portion 24b of the sliding control body 24.
High-pressure refrigerant gas is prevented from leaking from the compression chamber Pr to the suction pressure region side through the space between the compression chamber Pr and the suction pressure region.

As shown in FIGS. 1 and 3, one pair 1e' of the plurality of pairs of rear suction passages 1e, 1e' and suction holes 14a, 14a', which are opposed to each other with the sliding control body 24 in between,
14e', a pair of through holes L ₁ and L ₂ are provided in the cylindrical portion 24b of the sliding control body 24 near the screwing position of the nut 30. Moreover, the cylindrical portion 24b
A groove L ₁ is connected to the through hole L ₁ at the corner between the outer peripheral surface of the nut 30 and the inner end surface of the flange portion 24 a, and is recessed so as to be exposed outward in the radial direction of the nut 30 . A groove L ₂ is connected to the through hole L ₂ and is recessed so as to be exposed outward in the radial direction of the nut 30 .

Control pressure chamber 18a, rear side discharge chamber 2 in the discharge pressure region
0, the swash plate chamber 1a in the suction pressure region and the suction pipe 21 are connected to a capacity control valve mechanism (not shown), and the longitudinal displacement of the sliding control body 24 is controlled by fluctuations in the suction pressure within the suction pipe 21. It is becoming more and more like this.
That is, by opening and closing the valve body in the capacity control valve mechanism based on the suction pressure in the suction pipe line 21, the control pressure chamber 18a is controlled to be switched to a high pressure equivalent to the discharge pressure or a low pressure equivalent to the suction pressure, and the swash plate 9 is The position is switched between a maximum tilt angle position shown by a solid line and a minimum tilt angle position shown by a chain line in the figure.
In the front side compression chamber Pf, where the top dead center of the compression stroke is not constant, when the swash plate inclination angle is small, compression and expansion are only performed without substantial discharge, but when the top dead center of the compression stroke is constant. Rear side compression chamber Pr
In this case, substantial compression accompanied by discharge is performed regardless of the inclination angle of the swash plate 9.

Due to the suction action performed in the compression chamber Pr as the rotating shaft 4 rotates, the refrigerant gas in the swash plate chamber 1a passes through the rear suction passages 1e, 1e', the rear suction chamber 18, and the suction holes 14a, 14a' and enters the compression chamber. Introduced to Pr.
Due to this flow action, a part of the refrigerant gas introduced into the rear suction chamber ₁₈ from the rear suction passage 1e' adjacent to the groove l1 passes through the groove _l1 and the through hole _L1 to the guide bush 7 and the sliding control body. 24 into the gap S between the cylindrical portion 24b and the rear suction chamber ₁ through the through hole L1 and the groove _L2 .
Leaving to 8. Due to this passing action, a part of the refrigerant gas introduced into the gap S reaches the friction area of the radial bearing 26, and this friction area is lubricated by the mist of lubricating oil in the refrigerant gas. Therefore, it is possible to lubricate the friction portion of the radial bearing 26 surrounded by the race 31 and the sliding control body 24, thereby preventing early wear and deterioration of the radial bearing 26, and improving the reliability of the radial bearing 26.

The present invention is, of course, not limited to the above-mentioned embodiment, but also includes the embodiments shown in FIGS. 4 and 5, for example. In this embodiment, the cylindrical portion 2 of the sliding control body 24
Grooves l ₃ and l ₄ connected to through holes L ₁ and L ₂ penetrated through 4b
are recessed only on the outer peripheral surface of the cylindrical portion 24b, and grooves _l5 and _l6 are formed at the tip of the screw tightening member 27, and grooves _l7 and _l8 are formed at the edge of the nut 30, which are different from the above embodiment. A similar refrigerant gas supply effect can be obtained.

Furthermore, in the present invention, it is possible to appropriately increase the number of through holes and increase the number of grooves in each of the above embodiments in accordance with this increase, or omit the leak prevention screw tightening member in each of the above embodiments. It is also possible to apply the present invention to a compressor.

[Effects of the invention] As detailed above, in the present invention, a passage is provided through the sliding control body to communicate the gap between the guide bush and the sliding control body and the suction pressure region. Refrigerant gas can be supplied to the frictional parts of the radial bearing interposed between the guide bush and the sliding control body, and the mist of lubricating oil in the refrigerant gas lubricates the frictional parts, causing the radial bearing to be damaged early. This has the excellent effect of avoiding functional deterioration.

[Brief explanation of drawings]

The drawings show an embodiment embodying the present invention, and the first
The figure is a side sectional view, FIG. 2 is a sectional view taken along line A-A in FIG. 1, FIG. 3 is a sectional view taken along line B-B, FIG. 5 is a cross-sectional view taken along the line CC in FIG. 4. FIG. Cylinder block...1, Rotating shaft...4, Guide bush...7, Rear side suction chamber...18, Control pressure chamber...18a, Sliding control body...24, Radial bearing...26, Consists of supply passage The through hole...
...L ₁ , L ₂ , grooves...l ₁ to _{l 8} , gaps...S.

Claims (1)

[Scope of utility model registration request] A rotary shaft is rotatably housed and supported within a cylinder block that reciprocably accommodates a double-headed piston, and a swash plate that drives the double-headed piston to reciprocate is attached to this rotary shaft so that it is not relatively rotatable and moves back and forth around its periphery. In a swash plate type compressor that is swingably supported and has a compression stroke top dead center in a rear cylinder bore as a fixed position, a guide bush that supports the swing of the swash plate is slidably fitted and supported on the rotating shaft,
A control pressure chamber for capacity control is provided in the suction chamber partitioned from the rear cylinder bore by a partition plate, and a sliding control body for changing the volume of this control pressure chamber is inserted through the partition plate and cylinder block to control the guide bush. A passage is fitted to the outer periphery via a radial bearing, and passes through the sliding control body to communicate the gap between the guide bushing and the sliding control body with the suction pressure region and to supply refrigerant gas to the gap. A variable capacity swash plate compressor installed in