Fluid compression device

Abstract

The invention relates to a device for compressing a fluid, comprising: - a first member for compressing the fluid, oriented along a first axis (A), - a drive shaft, which is coaxial with the first axis (A), - a pin (56), which is offset parallel to the first axis (A), - a second member for compressing the fluid, which is oriented along a second axis (B) offset parallel to the first axis (A) and is intended to cooperate with the first compressing member in an orbital movement, - a bearing (58) which bears said second compressing member and comprises an inner ring (60) driven in rotation by the drive shaft, the ring (60) having an eccentric bore (62) with respect to the second axis (B), received on the pin (56), the bore (60) and the pin (56) being of axis (C) which is offset parallel to the first and second axes (A, B).

Description

FLUID COMPRESSION DEVICE

[0001] The invention relates to a fluid compression device, in particular for a thermoregulation circuit such as an air conditioning circuit of a motor vehicle.

[0002] In temperature control systems, such as heating, ventilation, and / or air conditioning systems, compressors are generally used to increase the pressure of a refrigerant from low to high. Roll compressors, also known as rolling piston compressors, and scroll compressors, also known as spiral compressors, are particularly well-known.

[0003] Unlike traditional compressors that use pistons or screw gears to compress the refrigerant, such "roll" and "scroll" compressors use a fixed compression member and a moving compression member that is driven in an orbital motion to cooperate with the fixed compression member.

[0004] Thus, in a "roll" compressor, the fixed compression element consists of a fixed stator in the shape of a cylinder and the mobile compression element consists of a mobile cylindrical piston which is mounted to roll eccentrically in this stator.

[0005] The stator surrounds the cylindrical piston. It has a cylindrical wall, which is oriented along a first axis, on which the piston rolls, and which together with the piston form two compression chambers where the fluid is successively compressed.

[0006] To ensure the orbital movement of the rolling piston, the compressor has a drive shaft coaxial with the first axis. The piston, driven by the shaft, is eccentric and oriented around a second axis that is offset parallel to the first axis.

[0007] In a "scroll" compressor, the fixed compression element consists of a fixed spiral and the mobile compression element consists of a mobile spiral which is mounted in a circular translational movement in an eccentric manner in the fixed spiral.

[0008] The fixed spiral is oriented along a first axis and forms compression chambers with the moving spiral where the fluid is successively compressed.

[0009] To ensure the orbital movement of the moving spiral, the compressor includes a drive shaft coaxial with the first axis. The moving spiral is supported by a plate, driven by the shaft, which is eccentric and oriented along a second axis that is offset parallel to the first axis.

[0010] Conventionally, in each of these compressor types, the moving compression element is mounted on a coaxial bearing, driven in its orbital motion by a pin, which is fixed to the drive shaft and oriented along the second axis. However, it has been observed that it is possible to improve the cooperation between the moving compression element and the fixed compression element by offsetting the axis of the bearing relative to that of the pin. To achieve this, a sleeve is generally interposed between the pin and an inner ring of the bearing. The sleeve has an outer surface, oriented along the second axis and received in an inner ring of the bearing, and a bore oriented along a third axis offset from the second axis, which is received on the pin.

[0011] Such a socket has the disadvantage of requiring complex machining.

[0012] There is therefore a real need for a simplified mounting of the mobile compression element on the pin.

[0013] The invention satisfies this need by proposing a fluid compressor comprising an eccentric bearing replacing the assembly formed by the coaxial bearing and the eccentric bushing.

[0014] To this end, the invention proposes a fluid compression device, in particular for thermoregulation circuit, said device comprising: - a first compression member of said fluid, oriented along a first axis (A), - a drive shaft, coaxial with the first axis (A), said shaft carrying a pin, offset parallel to the first axis (A), - a second compression member of said fluid, oriented along a second axis (B), offset parallel to the first axis (A), said second compression member being intended to cooperate with said first compression member in an orbital movement, - a bearing carrying said second compression member and having an inner ring intended to be driven in rotation by said drive shaft, said inner ring having a bore received on said pin, said bore and said pin having an axis (C) offset parallel to the first axis (A) and to the second axis (B).

[0015] Advantageously, the use of an eccentric bearing and the mounting of the inner ring of this bearing rotatably mounted directly on the shaft pin eliminates the need for an intermediate eccentric bushing between the pin and the bearing.

[0016] According to various additional features of the invention, which may be taken together or separately and which constitute so many embodiments of the invention: - the cooperation of the second compression element with the first compression element determines fluid compression chambers separated by an interface zone between the second element and an internal wall of the first compression element, - the interface zone is movable with the second compression element, - the bore of the inner ring is rotatably mounted on the shaft pin, - the second compression element comprises a bore receiving an outer bearing ring, rotatably mounted relative to the inner ring, - the second compression element is a rolling piston and the first compression element is a cylinder, - the cylinder comprises an inlet port and a discharge port, - said ports open into an internal wall of said cylinder.- said ports are separated by a tab elastically held in contact with said rolling piston, - the second compression member is a movable spiral volute and the first compression member is a fixed spiral volute in which the movable volute is engaged, - the device comprises an inlet port opening outside the fixed volute and a discharge port opening at the center of the fixed volute, - the movable volute is supported by a plate integral with the outer ring of the bearing, - the plate is limited in circular translational movement by means of a plurality of pins with axes (D) parallel to the first, second and third axes (A, B, C), each receiving at least one edge of the plate as a buttress, - the bearing is a ball or roller bearing, - said pin extends from a distal end of said shaft, - said pin is attached to said shaft, - said device comprises an imbalance compensation member,- The said unbalance compensation member is received on the said pin between a distal end of the drive shaft and the said bearing. - The said unbalance compensation member comprises a counterweight and a drive hub which includes the bore and carries the said counterweight. - The counterweight has at one of its axial ends a recess intended to receive, with clearance, a portion of the bearing. - The counterweight has at an opposite end a recess intended to receive the distal end of the drive shaft.

[0017] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent in the course of the detailed explanatory description which follows, of at least one embodiment of the invention given by way of purely illustrative and non-limiting example, with reference to the accompanying schematic drawings, among which: Fig.1

[0018] is an axial cross-sectional view of a spiral fluid compression device according to the invention, Fig. 2

[0019] is an end view of a drive assembly for a movable volute of a spiral compression device according to the invention, Fig.3

[0020] is an end view of a bearing implemented in the drive assembly according to the invention, Fig. 4

[0021] is an axial cross-sectional view of a drive assembly for a movable volute of a spiral compression device according to the invention, Fig. 5

[0022] is a schematic cross-sectional view of a rolling piston compression device according to the invention.

[0023] It should first be noted that the terms "first", "second", "third", etc., are used only to distinguish the components concerned from each other and do not imply any order or possible importance of said components.

[0024] As illustrated in Figure 1, the invention relates to a device 10 for compressing a fluid, particularly for heating, ventilation, and / or air conditioning systems, especially for motor vehicles. Said fluid comprises, for example, a refrigerant and a lubricating fluid. The refrigerant is composed, in particular, of a hydrofluorocarbon, such as that known as R-134a. Alternatively, it is, in particular, the fluid known as R1234yf or carbon dioxide, also known as R744.

[0025] In the illustrated embodiment, the device 10 comprises a compressor 12 for said fluid and an electric machine 14. The device 10 further comprises a housing 16 accommodating said electric machine 14 and said compressor 12. The housing 16 extends along a longitudinal axis A. The electric machine 14 includes, in particular, a motor 18, and a drive shaft 20 for the compressor 12 about the longitudinal axis A.

[0026] The compressor 12 is, for example, a scroll compressor. It comprises a first compression element 38 with axis A, here a fixed volute 38, and a second compression element 40, here a movable volute 40 with axis B. The fixed volute 38 is engaged in the movable volute 40, such that the volutes 38 and 40 each define a spiral housing. The movable volute 40 cooperates with the fixed volute 38 in an orbital motion, such that their spiral housings mutually define successive fluid compression chambers separated by an interface zone between the movable volute 40 and the fixed volute 38, this interface zone being movable with the second compression element. These chambers are arranged between at least one inlet port 42 and one discharge port 44 of the compressor 12. The movable volute 40 is driven in rotation by the shaft 20 so that the fluid passes from one chamber to the other while being progressively compressed.

[0027] The compressor 12 here has several fluid inlet ports 42, preferably consisting of two suction ports, located at a periphery of the compressor 12 and in particular opening outside the fixed volute 38. The compressor 12 also has a discharge port 44, for example located in a fixed central part of the compressor 12, i.e. opening into the center of the fixed volute 38.

[0028] The inlet ports 42 allow the fluid to enter between the fixed volute 38 and mobile volute 40 to be progressively compressed while being drawn towards the central part of the compressor 12 from where it exits through the discharge port 44.

[0029] For this purpose, the movable scroll 40 has an axis of rotation B which is offset radially and parallel to the longitudinal axis A. The axis of rotation B of the movable scroll 40 thus rotates around the axis of rotation A of the shaft 20. The movable scroll 40 is further mounted by means of a pivot joint so as to be free to rotate around its own axis of rotation B.

[0030] The device 10 further includes an intermediate piece 46, mounted freely to rotate around the shaft 20, to guide the movable volute 40, according to the desired movement, in the fixed volute 38. The intermediate piece 46 has a plurality of pins 48 with axes D, parallel to the first and second axes A, B, and each receiving as a stop at least one edge of the movable volute 40.

[0031] Given the asymmetries introduced by the mobile volute 40, such a movement generates an imbalance phenomenon likely to cause vibrations.

[0032] To limit this phenomenon, the device 10 advantageously includes an imbalance compensation element 50, implemented in the form of a mass, the device 10 being configured so that the element 50 allows balancing of the drive of the shaft 20. Such an element 50 makes it possible, in particular, to balance the rotation of the shaft 20 during the rotation of the moving volute 40 of the compressor. This will be discussed further later in relation to a particular aspect of the invention.

[0033] The device 10 has a fluid inlet 52 in the housing 16, and a fluid outlet 54. The fluid thus enters the housing 16 through the inlet 52, at low pressure, passes axially through the motor 18 and then the compressor 12, into which it enters through the suction ports 42 and exits through the outlet port 44, to exit, at high pressure, through the outlet 54.

[0034] Conventionally, the movable volute 40 is mounted on a coaxial bearing 58, driven in its orbital movement by a pin 56, fixed to the drive shaft and oriented along the second axis B. However, it has been observed that it is possible to improve the cooperation between the movable compression member 40, which is the movable volute 40 here, and the fixed compression member 38, which is the fixed volute 38 here, by offsetting the axis of the bearing relative to that of the pin 56. This offset makes it possible to increase the contact pressure in the interface zone between the movable volute 40 and the fixed volute 38 and consequently the sealing between the chambers of said device.

[0035] In accordance with the invention and as illustrated in figures 1 and 2, it is understood that the shaft 20 carries the pin 56, said pin 56 being offset parallel to the first axis A.

[0036] Preferably, the pin 56 extends from a distal end 57 of the tree 20. It may be made from material of said tree 20 or attached to it, as is the case on the.

[0037] According to the invention, the bearing 58 carries the second compression member, here the movable volute 40. This bearing 58 comprises an inner ring 60 intended to be driven in rotation by the drive shaft 20. The inner ring 60 has an eccentric bore 62 with respect to the second axis B, which is received on the pin 56. The inner ring 60 of the bearing 58 is thus attached to the pin 56 without an intermediate part. The bore 62 and the pin 56 are oriented along an axis C, which, as the axis of the pin 56, is offset parallel to the first axis A, and, as the axis of the bore, is offset with respect to the second axis B.

[0038] As illustrated in Figure 1, the bearing 58 is advantageously a ball bearing 59 or a roller bearing. The inner ring 60 extends continuously between the bore 62 and a contact surface 78 for the balls 59 or rollers. It has two opposing flat faces 80, 82 connected internally by walls 84 of said bore 62 and / or externally by an edge at which said contact surface 78 is located. Said edge provides a raceway for said balls 59 or rollers.

[0039] Regarding the mounting of the bearing 58, the bore 62 of the inner ring 60 is rotatably mounted on the pin 56 of the shaft 20. The movable volute 40 has a bore 64 receiving an outer ring 66 of the bearing, which is rotatably mounted relative to the inner ring 60. The movable volute 40 is more specifically supported by a plate 74 which is integral with the outer ring 66 of the bearing 58. It is this plate 74 which is limited in its circular translational movement by means of the plurality of pins 48 with axes D parallel to the first and second axes A, B and in this case also to the axis C, and which are received as abutments against at least one edge 76 of the plate 74.

[0040] Without limitation of the invention, it could be applied to any other type of compression device comprising a compressor having a movable compression member cooperating in an orbital motion with a fixed compression member.

[0041] Thus, as illustrated, the compressor 12 can be a rolling piston compressor, comprising a rolling piston 40 moving in an orbital motion in a cylinder 38.

[0042] In this case, the cylinder 38, as in the previous case, has an inlet port 42 and a discharge port 44. The ports 42 and 44 open into an internal wall 69 of the cylinder 38. The ports 42 and 44 are separated by a tab 67 which is elastically pulled back into contact with the rolling piston 40.

[0043] The piston 40 and the cylinder 44 mutually define two successive fluid compression chambers 68, 70 which are separated by an interface zone 72 between the rolling piston 40 and the cylinder 38, and arranged between the inlet port 42 and the discharge port 44. The interface zone 72 is movable with the rolling piston 40 so as to discharge the gases towards the outlet 44 of the compressor 12.

[0044] As illustrated in figures 1 and 4, the unbalance compensation member 50 is advantageously received on the pin 52 between the distal end 57 of the drive shaft 20 and the bearing 58. The unbalance compensation member 50 includes for this purpose a bore 86 which is traversed by the pin 52.

[0045] More specifically, the unbalance compensation member comprises a weight 88 and a drive hub which carries the weight 88 and has the bore 86. As can be seen in the figure, the weight has at one of its axial ends a recess 92 intended to receive with clearance a part of the bearing 58, and at an opposite end a recess 94 intended to receive the distal end of the drive shaft 20. This allows the unbalance compensation member not to significantly increase the axial dimensions of the device 10.

Claims

A fluid compression device (10), particularly for a thermoregulation circuit, said device (10) comprising: - a first fluid compression member (38), oriented about a first axis (A), - a drive shaft (20), coaxial with the first axis (A), said shaft carrying a pin (56), offset parallel to the first axis (A), - a second fluid compression member (40), oriented about a second axis (B), offset parallel to the first axis (A), said second compression member (40) being intended to cooperate with said first compression member (38) in an orbital motion, - a bearing (58) carrying said second compression member (40) and having an inner ring (60) intended to be driven in rotation by said drive shaft (20), said inner ring (60) having a bore (62) received on said pin (56), said bore (60) and said pin (56) having an offset axis (C) parallel to the first axis (A) and the second axis (B). Fluid compression device (10), wherein the cooperation of the second compression member (40) with the first compression member (38) determines fluid compression chambers separated by an interface zone between the second member (40) and an internal wall of the first compression member (38), said interface zone being movable with said second compression member (40). Fluid compression device (10) according to one of claims 1 or 2, in which the bore (62) of the inner ring (60) is rotatably mounted on the pin (56) of the shaft (20). Fluid compression device (10) according to any one of claims 1 to 3, in which the second compression member (40) has a bore (64) receiving an outer ring (66) of the bearing (58), mounted to rotate relative to the inner ring (60). Fluid compression device (10) according to any one of claims 1 to 4, wherein the second compression member (40) is a rolling piston and the first compression member (38) is a cylinder. Fluid compression device (10) according to the preceding claim, in which the cylinder has an inlet port (42) and a discharge port (44), opening into an internal wall (69) of said cylinder, and separated by a tab (67) elastically returned to contact with said rolling piston (40). Fluid compression device (10) according to any one of claims 1 to 4, wherein the second compression member (40) is a mobile spiral volute and the first compression member (38) is a fixed spiral volute in which the mobile volute is engaged. Fluid compression device (10) according to the preceding claim, comprising an inlet port (42) opening outside the fixed volute (38) and a discharge port (44) opening into the center of the fixed volute (38). Fluid compression device (10) according to any one of claims 7 or 8, in which the movable volute (40) is carried by a plate (74) integral with the outer ring (66) of the bearing (58), said plate (74) being limited in a circular translational movement by means of a plurality of pins (48) with axes (D) parallel to the first, second and third axes (A, B, C), each receiving as a butt at least one edge (76) of the plate (74). Fluid compression device (10) according to any one of the preceding claims, comprising an imbalance compensation member (50) which is received on said pin (56) between a distal end (57) of said drive shaft (20) and said bearing (58).

Images