Structure for supporting swash plate of variable displacement swash plate type compressor

Abstract

A structure for supporting a swash plate of a variable displacement swash plate type compressor is disclosed. The structure has a spherical sleeve slidably mounted on the drive shaft, a journal mounted on an outer surface of the sleeve and inserted in the swash plate, and a pair of pins adapted to connect the journal to the sleeve. An external diameter of the sleeve is smaller than an internal diameter of the journal, so that a predetermined gap is provided therebetween. Since the sleeve and the journal are not in contact with each other but connected to each other by the pins, a precise machining operation of the facing surfaces thereof and an additional machining operation for flat surfaces are not necessary, thereby facilitating machining of the sleeve and the journal. Lubrication therebetween is also not necessary.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a swash plate type compressor for use in an air conditioning for vehicles, and, more particularly, to a variable displacement swash plate type compressor having a structure capable of supporting a swash plate while enabling adjustment of the swash plate with respect to a drive shaft.

[0003] 2. Description of the Related Technology

[0004] A swash plate type compressor adapted to be predominantly used in an air conditioning for vehicles is constructed such that a disc-shaped swash plate, which is obliquely mounted on a drive shaft for receiving power from an engine, is rotated by the drive shaft, and a plurality of pistons coupled to a peripheral portion of the swash plate through shoes are linearly reciprocated in associated cylinder bores formed in a cylinder block by a rotation of the swash plate to cause refrigerant gas to be inhaled, compressed and exhausted.

[0005] A variable displacement swash plate type compressor has a swash plate, which is mounted on a drive shaft to be varied in its inclined angle according to thermal load, so that reciprocating amounts of pistons are varied to cause refrigerant compression amount to be controlled.

[0006] In FIG. 1, there is shown an example of such a variable displacement swash plate type compressor disclosed in Japanese patent Laid-open No. H 11-125176.

[0007] As shown in the drawing, the variable displacement swash plate type compressor includes a cylinder block 1 having a plurality of cylinder bores 1a, which are longitudinally disposed at its peripheral portion and are parallel to each other, a front housing 2 hermetically connected to a front end of the cylinder block 1, and a rear housing 3 hermetically connected to a rear end of the cylinder block 1 through a valve plate 3a.

[0008] A crank chamber 4 defined by the front housing 2 is centrally provided with a drive shaft 5 which passes through the center of the front housing 2 and is rotatably supported by the front housing 2. A rug plate 6 and a swash plate 7 are rotatably mounted on the drive shaft 5. The rug plate 6 is adapted to be rotated together with the drive shaft 5. The swash plate 7 is mounted on the drive shaft 5 to be inclined at a predetermined angle. The swash plate 7 is coupled at its end to the rug plate 6 by means of a hinge means 8 so that the swash plate 7 is rotated together with the rug plate 6 while axially sliding along the drive shaft 5 to enable its incline angle to be varied.

[0009] The swash plate 7 is connected at its peripheral portion to a plurality of pistons 9 through shoes 10 at a certain spacing. The plurality of pistons 9 are reciprocated in the cylinder bores 1 a respectively.

[0010] The rear housing 3 is provided with an intake chamber 11 and an exhaust chamber. A valve plate 3a is formed with an intake opening 13 and an exhaust opening 14.

[0011] In the drawing, reference numerals 15 and 16, which are not explained, denote an intake reed valve and a discharge reed valve adapted to open and close the intake opening 13 and the exhaust opening 14 of the valve plate 3a, respectively, reference numeral 17 denotes a spring interposed between the rug plate 6 and the swash plate 7 for biasing the swash plate 7 with respect to the rug plate 6. A control valve(not shown) is adapted to operatively communicate the crank chamber 4 and the intake chamber 11 for varying differential pressure between refrigerant pressure in the cylinder bore 1a and gas pressure in the crank chamber 4, thereby causing an incline angle of the swash plate to be controlled.

[0012] Such this type of variable displacement swash plate type compressor is constructed such that the pistons 9, which are slidably connected to the swash plate 7, are reciprocated by the swash plate 7 repeatedly moving back and forth while rotating together with the drive shaft 5 to cause refrigerant to be compressed, and the inclined angle of the swash plate 7 is controlled according to differential pressure between pressure in the crank chamber 4 and the cylinder bores la to cause exhaust amount of the compressor to be varied.

[0013] In the variable displacement swash plate type compressor, since a through bore centrally formed at the swash plate 7 must regulate radial movement of the swash plate 7 with respect to the drive shaft 5 and also must allow stable axial movement of the swash plate 7 while axially sliding along the drive shaft 5, an inner surface of the through bore must accommodate variation of an inclined angle of the swash plate 7 with respect to the drive shaft 5 on the one hand and must have a shape capable of stably supporting the drive shaft 5 under the condition that the swash plate 7 is inclined at a predetermined angle on the other hand.

[0014] To this end, the conventional compressor has a structure for supporting a swash plate wherein a sleeve 20 is slidably inserted over the drive shaft 5, and the sleeve 20 is inserted into the through bore of the swash plate 7 having a spherical inner surface, so that the spherical sleeve 20 comes into contact with the spherical inner surface of the swash plate 7, as illustrated in FIG. 1.

[0015] However, such a conventional structure for supporting a swash plate of a variable displacement swash plate type compressor has disadvantages in that it is difficult to achieve machining precision for spherical contacting surfaces of the sleeve 20 and particularly to machine the inner surface of a journal 30 in a spherical shape so as to exactly meet the outer surface of the sleeve. Furthermore, though the spherical contacting portions of the sleeve 20 and the inner surface of a journal 30 must be adhesively provided with oil mist contained in refrigerant to assure lubrication effect, oil mist experiences difficulty in flowing between and adhering to the spherical contacting portions because the through bore is in close contact with an outer surface of the sleeve 20.

[0016] In order to overcome the above-mentioned problems, Japanese Patent Laid-Open No. 11-125176 (published on May 5, 1999) discloses a structure for supporting a swash plate having a sleeve 20 mounted on a drive shaft 5 and a journal 30 mounted on the sleeve 20 and inserted in a through bore of a swash plate (not shown) characterized in that the sleeve 20 is formed at its diametrically opposite portions with a pair of parallel flat surfaces 25, and the journal 30 is formed at its through bore with a pair of flat surfaces 35 corresponding to the flat surfaces 25 of the sleeve 20, the flat surfaces 25 and 35 of the sleeve 20 and the journal 30 being slidably in contact with each other, the sleeve 20 and the journal 30 being coupled at their flat surfaces 25 and 35 to each other by means of pins 40, as shown in FIGS. 1 and 2 of the accompanying drawings.

[0017] However, such a conventional structure for supporting swash plate disclosed in the publication still has a problem in that the sleeve 20 and the journal 30 must be formed with flat surfaces 25 and 35, respectively, and the flat surfaces 25 and 35 must be precisely machined for sliding contact therebetween. In addition, though improvement of rubrication effect can be somewhat anticipated because the contact portions between the flat surfaces of the sleeve 20 and the journal 30 are broadened toward a crank chamber, the improvement of lubrication effect is limited due to the flat surfaces slidably contacting with each other.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

[0018] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a structure for supporting a swash plate of a variable displacement swash plate type compressor adapted to facilitate a machining operation for a sleeve and a journal without high-precision processing.

[0019] Another aspect of invention provides a structure for supporting a swash plate of a variable displacement swash plate type compressor which does not have slide contacting portions, thereby enabling lubrication therebetween to be unnecessary.

[0020] One embodiment of the invention provides a structure for supporting a swash plate of a variable displacement swash plate type compressor comprising: a spherical sleeve mounted on the drive shaft; a journal having a cylindrical bore for allowing the journal to be mounted on an outer surface of the sleeve, and inserted in the swash plate; and a pair of pins adapted to connect the journal to the sleeve and to allow the journal to be turned with respect to the sleeve. The sleeve is shaped such that its external diameter is smaller than an internal diameter of the journal (or a diameter of the cylindrical bore), so that a predetermined gap is provided therebetween. Surfaces of a pair of pins and the sleeve tightly contact each other. Furthermore, each diameter of pin sections to be connected with the journal and diameter of pin sections to be connected with the sleeve may be different from each other. In this case, it is preferred that diameter of pin section to be connected with the journal is larger than that of pin section to be connected with the sleeve. For example, the pin section to be connected with the sleeve may has a cone shape. Furthermore, each of pin sections to be connected with the journal has threaded portion.

[0021] Another embodiment of the invention provides an apparatus comprising; a sleeve having an outer surface, a first through-hole and a second through-hole substantially perpendicular to the first through-hole; and a journal having a surface defining a first through-hole, the journal further having a second through-hole substantially perpendicular to the first through-hole of the journal. In addition, at least a part of the sleeve is located within the first through-hole of the journal in a way that the second through-holes of the sleeve and journal are arranged to receive a pin, and the surface of the journal is separated from the outer surface of the sleeve with a gap in a cross section where the second through-holes of the sleeve and journal are formed. The gap is from about 0.025 to about 1 mm, or from about 0.05 to about 0.5 mm, or from about 0.075 to about 0.25 mm. The second through-holes of the sleeve and journal have different diameters. The diameter of the second through-hole of the journal is larger than that of second through-hole of the sleeve. The second through-hole of the sleeve has a cone shape. The second through-hole of the journal has a saw tooth shape.

[0022] Another embodiment of the invention provides a compressor comprising the above apparatus.

[0023] Still another embodiment of the invention provides an air conditioner comprising the above compressor.

[0024] Yet another embodiment of the invention provides an apparatus comprising a sleeve having an outer surface, a first through-hole and a second through-hole substantially perpendicular to the first through-hole; and a journal having a surface defining a first through-hole, the journal further having a second through-hole substantially perpendicular to the first through-hole of the journal. In addition, at least part of the sleeve is located within the first through-hole of the journal in a way that the second through-holes of the sleeve and journal are arranged to receive a pin, and a predetermined sized gap is provided between the outer surface of the sleeve and the surface of the journal such that the outer surface of the sleeve does not contact the surface of the journal, wherein the gap is provided in a cross section where the holes of the sleeve and the journal are formed. The gap is from about 0.025 to about 1 mm, or from about 0.05 to about 0.5 mm, or from about 0.075 to about 0.25 mm.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0026] FIG. 1 is a longitudinal cross-sectional view showing a variable displacement swash plate type compressor disclosed in Japanese patent Laid-open No. H 11-125176.;

[0027] FIG. 2 is a longitudinal cross-sectional view showing a structure for supporting a swash plate of the variable displacement swash plate type compressor shown in FIG. 1.;

[0028] FIG. 3 is a longitudinal cross-sectional view showing a structure for supporting a swash plate of a variable displacement swash plate type compressor, according to an embodiment of the invention;

[0029] FIG. 4 is a cross-sectional view of FIG. 3; and

[0030] FIGS. 5 a to 5d are cross-sectional views similar to FIG. 4, which show various embodiment of the invention.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

[0031] Reference now should be made to the drawings, in which the same reference numerals are used throughout the different drawings to designate the same or similar components.

[0032] FIG. 3 is a longitudinal cross-sectional view showing a structure for supporting a swash plate of a variable displacement swash plate type compressor according to an embodiment of the invention, FIG. 4 is a cross-sectional view of FIG. 3, and FIGS. 5a, 5b, 5c and 5d are views similar to FIG. 4, showing another embodiments of the invention.

[0033] As shown in FIGS. 3 and 4, a structure for supporting a swash plate of a variable displacement swash plate type compressor according to the invention includes a spherical sleeve 100 mounted on a drive shaft 5, a journal 200 mounted on an outer surface of the sleeve 100 and inserted in a swash plate (not shown), and a pair of pins 300 adapted to connect the sleeve 100 and the journal 200 and to allow the journal 200 to be rotated with respect to the sleeve 100.

[0034] The sleeve 100 is formed at its diametrically opposite portions with pin holes 120 for receiving the pins 300. The journal 200 is also formed with pin holes 220 at positions corresponding to the pin holes 120 of the sleeve 100. The pins 300 are also inserted in the pin holes 220 of the journal 200. The journal 20 is provided at its outer surface with a threaded portion 230 for being engaged with a threaded portion of a swash plate.

[0035] An internal diameter (D2) of the journal 200, i.e., a diameter of a cylindrical bore 210 is shaped to be a little larger than Maximum external diameter (D1) of the sleeve 100.

[0036] When considering the exactness and easiness of machining the surface of the outer surface of the sleeve and the inner surface of the journal as well as considering stable rotational performance of the swash plate not trembled while acquiring any degree of inclination thereof, a range of distance between these two diameters (D1, D2) is about 0.025 mm to about 1 mm. A preferable range of distance between D1 and D2 is about 0.05 mm to about 0.5 mm. A more preferable range of distance between D1 and D2 is about 0.075 mm to about 0.25 mm.

[0037] As a result, as shown in FIGS. 3 and 4, a predetermined gap(distance between diameters D1, D2)400 is formed between the outer surface of the sleeve 100 and an inner surface of the cylindrical bore 210 of the journal 200.

[0038] The pins 300 are vertically inserted into the drive shaft 5 through the pin holes 120 and 220 of the sleeve 100 and the journal 200 to rotatably connect the journal 200 to the sleeve 100. At this point, where the pins 300 inserted in the pin holes are completely inserted in the pin holes not to be protruded outside, a swash plate can be easily coupled to the journal.

[0039] The pins 300 may include such common cylindrical pins as pins shown in FIGS. 3 and 4, and such pins having various shapes as pins shown in FIGS. 5a to 5d. In addition to that, pins having any shapes capable of rotatably connecting the journal 200 to the sleeve 100 can be also used. Among the pins shown in FIGS. 5a to 5d, the pins 300 shown in FIGS. 5a and 5c have two cylindrical parts having diameters different from each other. That is, a diameter of an inner cylindrical part to be inserted in the sleeve 100 is smaller than that of an outer cylindrical part to be inserted in the journal 200. Pins 300 shown in FIG. 5b have threaded portions at their outer parts to be inserted in the journal 200 to securely support the journal 200. In the pins shown in FIG. 5b, an inner part of the pin 300 is not provided with a threaded portion to assure smooth sliding motion of the journal 200. Pins 300 shown in FIG. 5d have the cone-shaped inner parts.

[0040] In fabrication of the structure for supporting a swash plate according to the invention, the sleeve 100 is first inserted into the cylindrical bore 210 of the journal 200. Subsequently, the pin holes 120 of the sleeve 100 are aligned with the pin holes 220 of the journal 200, and then the pins 300 are inserted into the pin holes 120 and 220. Thereafter, the outer threaded portion 230 of the journal 200 is engaged with the mating threaded portion of the swash plate. The swash plate assembly fabricated in this way is finally mounted on the drive shaft 5.

[0041] Since the external diameter of the sleeve 100 is shaped to be smaller than the internal diameter of the journal 200, a predetermined gap is formed therebetween, and the sleeve 100 and the journal 200 are connected to each other only by the pins 300.

[0042] The structure for supporting a swash plate constructed as described above is designed to enable an incline angle of the swash plate with respect to the drive shaft to be easily controlled by differential pressure between a crank chamber and an exhaust chamber. Since the sleeve 100 and the journal 200 are connected to each other by means of the pins 300, the journal does not slide on the outer surface of the sleeve 100 but rotates about the pins 300.

[0043] Since a journal according to the prior art is in close contact with a sleeve, it is difficult to achieve lubrication between the journal and the sleeve. However, since a predetermined gap is provided between the sleeve and the journal, additional lubrication therebetween is not necessary.

[0044] Furthermore, though the contacting surfaces of the journal and the sleeve according to the prior art must be precisely machined, a precise machining of the facing surfaces of the journal and the sleeve according to the invention are not necessary because a predetermined gap is present between the journal and the sleeve.

[0045] As described above, according to the present invention, since a sleeve and a journal are not in contact with each other but connected to each other by means of pins, a precise machining operation for facing surfaces of the sleeve and the journal and an additional machining operation for flat surfaces are not necessary. Therefore, the sleeve and the journal can be easily produced. Furthermore, since the sleeve and the journal are not in contact with each other, lubrication therebetween is not necessary.

[0046] Although preferred embodiments of the present invention have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

1. A structure for supporting a swash plate in such a manner that an incline angle of the swash plate can be controlled with respect to a drive shaft, comprising: a sleeve mounted on the drive shaft; a journal having a bore for allowing the journal to be mounted on an outer surface of the sleeve, and inserted in the swash plate; and a pair of pins adapted to connect the journal to the sleeve and to allow the journal to be turned with respect to the sleeve; wherein an outer surface of the sleeve is smaller than a surface of the bore, so that a predetermined gap is provided therebetween.

2. A structure for supporting a swash plate of a variable displacement swash plate type compressor according to claim 1, wherein surfaces of said pins and said sleeve tightly contact each other.

3. A structure for supporting a swash plate of a variable displacement swash plate type compressor according to claim 1, wherein each diameter of said pin sections to be connected with the journal and diameter of said pin sections to be connected with the sleeve are different from each other.

4. A structure for supporting a swash plate of a variable displacement swash plate type compressor according to claim 3, wherein the diameter of the pin section to be connected with the journal is larger than that of the pin section to be connected with the sleeve.

5. A structure for supporting a swash plate of a variable displacement swash plate type compressor according to claim 3, wherein said pin section to be connected with the sleeve has a cone shape.

6. A structure for supporting a swash plate of a variable displacement swash plate type compressor according to claim 1, wherein each of said pin sections to be connected with the journal has a threaded portion.

7. An apparatus, comprising; a sleeve having an outer surface, a first through-hole and a second through-hole substantially perpendicular to the first through-hole; and a journal having a surface defining a first through-hole, the journal further having a second through-hole substantially perpendicular to the first through-hole of the journal; wherein at least part of the sleeve is located within the first through-hole of the journal in a way that the second through-holes of the sleeve and journal are arranged to receive a pin, and wherein the surface of the journal is separated from the outer surface of the sleeve with a gap in a cross section where the second through-holes of the sleeve and journal are formed.

8. The apparatus of claim 7, wherein the gap is from about 0.025 to about 1 mm.

9. The apparatus of claim 7, wherein the gap is from about 0.05 to about 0.5 mm.

10. The apparatus of claim 7, wherein the gap is from about 0.075 to about 0.25 mm.

11. The apparatus of claim 7, wherein the second through-holes of the sleeve and journal have different diameters.

12. The apparatus of claim 11, wherein the diameter of the second through-hole of the journal is larger than that of second through-hole of the sleeve.

13. The apparatus of claim 7, wherein the second through-hole of the sleeve has a cone shape.

14. The apparatus of claim 7, wherein the second through-hole of the journal has a saw tooth shape.

15. The apparatus of claim 7, wherein the apparatus is included in a compressor.

16. The apparatus of claim 15, wherein the apparatus is included in an air conditioner.

17. An apparatus, comprising; a sleeve having an outer surface, a first through-hole and a second through-hole substantially perpendicular to the first through-hole; and a journal having a surface defining a first through-hole, the journal further having a second through-hole substantially perpendicular to the first through-hole of the journal; wherein at least a part of the sleeve is located within the first through-hole of the journal such that the second through-holes of the sleeve and journal are arranged to receive a pin, and wherein a predetermined sized gap is provided between the outer surface of the sleeve and the surface of the journal such that the outer surface of the sleeve does not contact the surface of the journal, wherein the gap is provided in a cross section where the holes of the sleeve and the journal are formed.

18. The apparatus of claim 17, wherein the gap is from about 0.025 to about 1 mm.

19. The apparatus of claim 17, wherein the gap is from about 0.05 to about 0.5 mm.

19. The apparatus of claim 17, wherein the gap is from about 0.05 to about 0.5 mm.

20. The apparatus of claim 17, wherein the gap is from about 0.075 to about 0.25 mm.