Compressor unit, and compressor

Abstract

Compressor unit (12) of a compressor (10) for compressing refrigerant, comprising a drive device, particularly a drive shaft (24), for driving one or more pistons (14) that are arranged in a radial direction and that can be moved back and forth in extension and retraction movements in corresponding cylinder bores (16), wherein the drive device is in operative engagement with an eccentric (28) that controls the extension movement of the pistons (14), said eccentric (28) also controlling the retraction movement of the piston (14), the invention further relating to a corresponding compressor (10).

Claims

1. A compressor unit of a compressor for compressing refrigerant, the compressor unit comprising: a drive device that drives one or more pistons arranged in a radial direction and configured to move back and forth in extension and retraction movements in corresponding cylinder bores, and an eccentric in operative engagement with the drive device to control the extension and the retraction movement of the pistons, the eccentric having an operative eccentric section with a bearing having a circular outer perimeter and in operative engagement with one or more operative connecting rod sections of respective connecting rods, wherein the operative connecting rod sections are arranged on the bearing by an operative connecting rod section seat, whereby the movements of the connecting rods can be disengaged from each other and wherein the operative connecting rod sections are designed to correspond with the circular outer perimeter of the bearing and are shaped as a circular segment on their side facing the bearing and have an extension that widens in an axial direction at their end facing the bearing such that they are securely arranged on the bearing in two shells designed with an L-shaped cross-section and that form the operative connecting rod section seat.

2. The compressor unit according to claim 1, wherein the compressor unit has for each piston the respectively connecting rod that is articulated thereto by means of a connecting rod eye which is formed on the side of the connecting rod facing the respective piston.

3. The compressor unit according to claim 1, wherein the compressor unit has for each piston the respectively connecting rod that is in operative engagement with the eccentric by means of the operative connecting rod section that is formed on the side of the connecting rod facing the operative eccentric section.

4. The compressor unit according to claim 1, wherein the operative eccentric section has a circular cross-section, and/or in that the sides of the connecting rod facing the operative eccentric section are shaped as a circular segment.

5. The compressor unit according to claim 1, wherein the operative connecting rod sections are arranged concentrically on a circular path around the eccentric.

6. The compressor unit according to claim 5, wherein the bearing is arranged between the operative connecting rod section and the operative eccentric section.

7. The compressor unit according to claim 6, wherein the bearing is a needle bearing.

8. The compressor unit according to claim 1, wherein the compressor unit (12) has CO.sub.2 as a refrigerant.

9. The compressor unit according to claim 1, wherein the compressor unit has a stroke/bore ratio of 0.3 to 1.

10. The compressor unit according to claim 1, wherein the compressor unit has a stroke/bore ratio of 0.35 to 0.5.

11. The compressor unit according to claim 1, wherein the compressor unit has 3 to 8 pistons.

12. The compressor according to claim 1, wherein the drive device is a drive shaft.

13. The compressor unit according to claim 1, wherein the compressor unit has a stroke/bore ratio of 0.3 to 0.7.

14. The compressor unit according to claim 1, wherein the compressor unit has a stroke/bore ratio of 0.4.

15. The compressor unit according to claim 1, wherein the compressor unit has 4 to 6 pistons.

16. A compressor for compressing refrigerant wherein the compressor has a compressor unit according to claim 1.

17. The compressor according to claim 16, wherein the compressor has an electric motor for driving the compressor unit, wherein the electric motor is in operative engagement with the drive device, in particular the drive shaft, of the compressor unit.

18. The compressor according to claim 16, wherein the compressor is a hermetically designed compressor.

19. A compressor unit of a compressor for compressing refrigerant comprising a drive device for driving one or more pistons that are arranged in a radial direction and that can be moved back and forth in extension and retraction movements in corresponding cylinder bores, wherein the drive device is in operative engagement with an eccentric that controls the extension movement of the pistons, wherein the eccentric also controls the retraction movement of the pistons, the eccentric having an operative eccentric section with a bearing having a circular outer perimeter and in operative engagement with one or more operative connecting rod sections of respective connecting rods, wherein the operative connecting rod sections are designed to correspond with the circular outer perimeter of the bearing and are shaped as a circular segment on their side facing the bearing and have an extension that widens in an axial direction at their end facing the bearing such that they are securely arranged on the bearing in two shells designed with an L-shaped cross-section to form an operative connecting rod section seat.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Additional features of the invention are presented in the dependent claims.

(2) The invention will be described in the following with reference to the accompanying drawings using exemplary embodiments. The drawings show:

(3) FIG. 1 A sectional view of an embodiment of a compressor according to the invention in a section perpendicular to the axial direction;

(4) FIG. 2 Another sectional representation of a compressor according to the invention in a section parallel to the axial direction; and

(5) FIG. 1 shows a sectional view of a compressor 10 according to the invention, wherein the section is in the region of a compressor unit 12 of the compressor 10 according to the invention perpendicular to an axial direction.

DESCRIPTION OF PREFERRED EMBODIMENTS

(6) As can be seen in FIG. 1, a compressor unit 12 according to the invention has six pistons 14 that can be moved back and forth in a radial direction and are arranged in corresponding cylinder bores or cylinder linings 16. The cylinder bores or respectively cylinder linings 16 themselves are designed as corresponding recesses in a cylinder block 18. As mentioned above, the pistons 14 are designed such that they can move back and forth in the radial direction. In regard to this back-and-forth movement, a distinction is made below between an extension movement and a retraction movement, wherein the extension movement is directed in the radial direction toward the outside (illustrated by arrow 20), and the retraction movement is directed in a radial direction toward the inside (illustrated by arrow 22). The compressor unit 12 serves to compress refrigerant wherein, in the embodiments described herein and shown in the figures, R744 (CO.sub.2) preferably is the refrigerant. It should however be noted that use of any other refrigerant (such as R134a, etc.) is conceivable. Stated otherwise, the subject matter of the present invention is a refrigerant compressor for compressing refrigerant, in particular CO.sub.2. It is a compressor that in particular is provided for compressing gaseous media, i.e., a compressor for compressing gaseous refrigerant.

(7) Furthermore, the compressor unit 12 according to the invention has a drive device in the form of a drive shaft 24 (see for example FIG. 2), by means of which the compressor unit 12 can be driven. In the described embodiment of a compressor 10 according to the invention, the drive shaft is coupled to an electric motor (not shown), but can however also be coupled to a corresponding belt drive device or other device in an alternative embodiment. At this juncture, it is noted that the axial extension of the drive shaft 24, depending on the intended use, can also be shorter than the embodiment shown in the figures in which the drive shaft 24 is in operative engagement with the electric motor and extends through the electric motor.

(8) In the context of the extension and refraction movements of the pistons, the refrigerant is drawn into the cylinder bores or respectively cylinder liners 16 during a refraction movement of the pistons, is compressed upon execution of the extension movement, and is then ejected.

(9) The drive device in the form of the drive shaft 24 is in operative engagement with an eccentric 28. More precisely, the drive shaft 24 is designed eccentrically in a corresponding region (eccentric section of the drive shaft 24). The eccentric 28 is hence designed to be integral and a single piece with, and on, the drive shaft 24. In alternative embodiments, the eccentric 28 can also be designed as a separate component and attached to the drive shaft 24, in particular articulated or correspondingly mounted.

(10) In a section perpendicular to the axial direction, the eccentric 28 has a circular cross-section and eccentric surfaces 30 directed radially outward that are arranged in a region of an operative eccentric section 32. The operative eccentric section 32 serves to drive the pistons 14 and is in operative engagement with them by means of a connecting rod 34 assigned to each piston 14. For this, the connecting rods 34 are articulated to the pistons 14 by means of connecting rod eyes 36 that are formed on the sides of the connecting rods 34 facing the pistons 14.

(11) On the side facing the eccentric 28, the connecting rods 34 have an operative connecting rod section 38 that serves to operatively engage the eccentric 28. The eccentric 28 is in operative engagement with the operative connecting rod sections 38 by means of a bearing in the form of a needle bearing 40 that is arranged on the eccentric operating section 32 (circular cross-section) where it is arranged on the eccentric surface 30 (fitted). Alternatively to the needle bearing 40, other bearings are conceivable, in particular slide bearings or roller bearings in any possible design.

(12) The bearing 40 ensures a low friction transfer and conversion of the movement (rotary movement) of the eccentric 28 in a movement directed in a radial direction of an effective connecting rod section seat 42 that is in operative engagement with the bearing by means of a corresponding fit. The corresponding movement in a radial direction is then correspondingly transferred to the connecting rods 34 and the pistons 14 articulated thereto. The operative connecting rod sections 38 that are designed to correspond with the circular outer perimeter of the bearing 40 and are shaped as a circular segment on their side facing the bearing 40 have an extension that widens in an axial direction at their end facing the bearing such that they are securely arranged on the bearing 40 in two shells 44 designed with an L-shaped cross-section and that form the operative connecting rod section seat 42. The operative connecting rod sections of all connecting rods 34 are arranged on a circular path around the eccentric 28 and hence also around the operative eccentric section 32 that is concentric therewith.

(13) Because the pendulum point of the device is arranged eccentrically due to the use of the eccentric, the present construction in which circular-segment-like operative connecting rod sections are used and the movements of the connecting rods can be disengaged from each other, a different movement can occur in each case in the region of the respective pistons. If the connecting rods were rigidly coupled, a fault would arise in the stroke movement and hence increase the dead space in the region of the pistons distant from the pendulum point.

(14) In one possible embodiment, as mentioned above, the compressor unit 12 and hence the compressor 10 are a compressor unit 12 or respectively compressor 10 which is designed as a refrigerant compressor that has CO.sub.2 as a refrigerant, or for which CO.sub.2 is used as the refrigerant. In this compressor unit 12, the ratio of the stroke of a cylinder to the diameter of its bore is 0.3 to 1, in particular 0.3 to 0.7, and more particularly 0.35 to 0.5 and more particularly 0.4. In other words, the value of the stroke/bore ratio is 0.3 to 1, in particular 0.3 to 0.7, more particularly 0.35 to 0.5 and more particularly 0.4. These are the applicable stroke/bore ratios for the described possible embodiment, wherein a value from an interval from 0.3 to 1 can be selected depending on the design requirements. The other cited values with decreasing intervals are values that are preferred in terms of energy if they are feasible within the given design parameters.

(15) The compressor unit according to the invention has 3 to 8 pistons in possible embodiments, in particular 4 to 6 pistons. Particularly for CO.sub.2 compressors, more particularly for CO.sub.2 compressors of a small design, this is a favourable number of pistons for the design.

(16) It should be noted that the above-described embodiment of the compressor 10 has the electric motor 26 for driving the compressor unit 12, wherein the electric motor 26 is in operative engagement with the drive shaft 24 of the compressor unit 12, or respectively drives it. The compressor 10 of the described embodiment is a hermetically designed compressor, wherein it is noted that the concept according to the invention is of course applicable to open, semi-hermetic, hermetic and other compressors with a different design. The compressor does not have to be driven by an electric motor and can also be designed as a belt drive or another drive option that may be integrated in the compressor, or is also located outside of the compressor.

(17) Although the invention is described with reference to embodiments having fixed combinations of features, it also comprises conceivable, further advantageous combinations as are in particular, but not exhaustively, presented in the dependent claims. All of the features disclosed in the application documents are claimed as essential to the invention to the extent that they are novel over the preceding art by themselves or in combination.

LIST OF REFERENCE NUMBERS

(18) 10 Compressor 12 Compressor unit 14 Piston 16 Cylinder bores/cylinder linings 18 Cylinder block 20 Arrow 22 Arrow 24 Drive shaft 28 Eccentric 30 Operative eccentric surface 32 Operative eccentric section 34 Connecting rod 36 Connecting rod eye 38 Operative connecting rod section 40 Needle bearing 42 Operative connecting rod section seat 44 Shell