FR2853698A1 - OSCILLATING PLATE COMPRESSOR FOR VEHICLE AIR CONDITIONING EQUIPMENT - Google Patents

Abstract

In a compressor housing (1) is housed a drive shaft provided with a swash plate (5), which drives at least one reciprocating piston (8) for sucking and compressing a refrigerant, the reciprocating piston being housed in a compression cylinder, formed in a cylinder head (13). To reduce the operating noise emitted to the outside, a concentric peripheral slot (22) is formed between the cylinder head block (6) and the compressor housing (1), and the cylinder head block (6) rests firmly and firmly. sealed on the compressor housing (1) at its two front ends.

Description

The invention relates to a plate compressor

  Oscillating device intended to suck and compress refrigerant which circulates in a closed circuit, in particular refrigerant C02 (refrigerant R744), the swash plate compressor being driven mechanically or electrically.

  The swash plate compressors used in air conditioning equipment for motor vehicles are generally mechanically driven. Examples of this are found in DE 41 39 186 Ai or CH 690 189 A5. However, it has also already been proposed, in DE 101 35 733.8, to install in the compressor casing a variable speed electric motor acting as a drive for the compressor. A compressor 15 said to be hybrid with which the drive can be provided either by an electric motor or by the combustion engine of the vehicle is also known from patent EP 0 978 652 A2. Irrespective of the drive mode, these compressors have a drive shaft provided with a swash plate which generally drives several reciprocating pistons to suck and compress a refrigerant, the reciprocating pistons being respectively housed in a compression cylinder, which is formed in a cylinder head block fixed in the compressor casing 25 and made watertight with respect thereto. The compression cylinders are closed by a valve plate and the compressor housing by a valve cover. In the case of a mechanically driven compressor, the speed of rotation of the swash plate is as high as the speed of rotation of the motor and, during one revolution of the swash plate, just as in the case of a swash plate compressor electrically driven, all the reciprocating pistons connected to it are moved, like the suction and exhaust valves. The moving parts cause undesirable noise, especially at high rotational speeds, but also in the case of large piston strokes such as are necessary with a high cooling capacity.

  The object of the invention is to reduce the operating noise emitted to the outside by a swash plate compressor for air conditioning equipment of a motor vehicle.

  The invention consists, with a swash plate compressor, in the compressor housing of which is housed a drive shaft provided with a swash plate, which drives at least one reciprocating piston intended to suck up and compress a refrigerant, which is housed so as to be able to move back and forth in a compression cylinder formed on a cylinder head block, to form between the cylinder head block and the compressor housing a concentric peripheral slot and to rest the cylinder head block firmly and tightly on the compressor housing at both front ends. The compression cylinder is closed in a known manner on the side opposite the swash plate by a valve plate which is kept sealed on the compressor housing by a valve cover. This slot, which essentially surrounds the entire envelope surface of the cylinder head block, in which the operating noises linked to the movement of the piston occur and on which the noises are caused by the opening and the closing of the valves arranged in the valve plate as well as the transmission of the noises which occur in the crankshaft housing in which the swash plate is housed, considerably reduces the transmission of these noises on the compressor housing so that the noise load delivered by it to the environment is also reduced.

  So that the cylinder head block is housed in the compressor casing 35 securely and sealingly in the axial and radial directions, the latter is either provided at its two front ends each time with a shoulder with which it rests on the compressor housing. As a variant, the compressor housing can also be configured so as to form a slot in that the wall of the housing is provided, on its inner side in the region of the slot provided, with an annular recess. Sealing between the cylinder head block and the compressor housing can be achieved by O-rings in the area of the corresponding shoulder.

  At least the annular surface on the front side of the shoulder on the swash plate side or the latter as a whole is preferably inclined at an angle of 4 to 6 degrees relative to a plane perpendicular to the axis of the cylinder head block so as to that the outer edge of this annular surface is projecting. This slightly conical configuration of the shoulder allows better sealing of the cylinder head block relative to the compressor casing when the cylinder head block is housed under pretension in the compressor casing. The annular surface and the envelope surface of the shoulder are thus compressed and deformed against the corresponding surfaces of the compressor housing. An O-ring in the shoulder area is no longer required. This solution brings a considerable advantage, in particular in the case of the use of CO 2 refrigerant, which must be compressed significantly more than traditional refrigerants, approximately by a factor of 10, to obtain comparable cooling capacities, and with which the constraints in terms of sealing are more severe.

  The compression assembly of the cylinder head block with the compressor housing is done by screwing the valve cover onto the compressor housing.

  The shoulder on the side of the valve plate may in addition also be generally of slightly conical configuration in the direction of the swash plate and include respectively on the periphery an acute angle between its annular surfaces and a plane arranged perpendicular to the axis. of the breech block. The angle chosen is however essentially 0.5 degrees less than 5 the angle of inclination presented by the annular surface on the front side of the shoulder on the swash plate side.

  The shoulder on the swash plate side thus comes first to rest on the compressor casing when the cylinder head block is housed therein, and then to be compressed therewith so as to reliably seal the block. cylinder head relative to the compressor housing in the area of this shoulder. Continuing the screwing, the shoulder on the valve plate side is then compressed in turn, which further increases the reliability of the seal. O-rings are unnecessary with this embodiment, which makes the compressor overall more compact. The number of components is also reduced and the complexity of assembly is reduced.

  Since the compressor, as a homogeneous component, constitutes a wearing part, it is also possible to weld the valve cover with the compressor housing. To produce the prestress between the cylinder head block and the compressor casing, the valve cover 25 is held thereon under stress during the welding operation. The leakage losses on a welded compressor casing are lower than those on a screwed. In principle, the compressor housing can also be divided lengthwise to facilitate the accommodation of the functional elements therein and thus the mounting, and then be welded after housing. The valve cover is then also welded and prestressed with the compressor housing.

  The invention will be explained below with the aid of an exemplary embodiment. The corresponding drawings illustrate: Figure 1 a vertical section of a swash plate compressor with electric drive and Figure 2 the configuration of the cylinder head block in zone X in vertical section, enlarged compared to Figure 1.

  The swash plate compressor for refrigerant C02 with electric drive represented essentially diagrammatically in FIG. 1 according to patent DE 102 28 042.8 essentially presents a compressor casing 1, an electric motor 2 with variable speed by frequency excitation, a drive shaft 3 connected to it, a crankcase housing 4 for swash plate 5 having a predefined inclination and mounted on the drive shaft 15 3 so as not to be able to rotate therein , a cylinder head block 6 comprising several compression cylinders 7 in which are arranged cylinder liners 7.1 and in this reciprocating hollow cylindrical pistons 8 reciprocating and in active connection 20 with the swash plate 5, each associated with a suction valve 9, with a valve plate 10 comprising exhaust valves 12, which are associated with the chains respective compression members 11 formed in the compression cylinders 7, and a valve cap 25 constituting almost a cylinder head provided with a high pressure chamber 14 and an oil separator 15 housed therein. The active connection of a reciprocating piston 8 with the swash plate 5 is achieved by a hinge head formed thereon and by a housing support L formed on the reciprocating piston 8 therefor.

  The suction of the refrigerant C02 is effected by means of the suction sleeve 16 which is formed on a closing cover 17 coaxial with the drive shaft 3 and arranged on the motor side. A suction port 18 extends from the suction sleeve 16 into the engine chamber. The refrigerant C02 sucked through the suction sleeve 16 and the suction port 18 flows through the engine chamber and leaves the latter through the through orifices 19 which are housed in an intermediate wall 20 separating the engine compartment and the crankcase 4, then arrives in the space of the crankcase.

  The suction valves 9 are each located on the front side opposite the swash plate 5 of the reciprocating piston 8 provided on the side of the swash plate with an opening (not shown) and open into the compression chamber 11 corresponding. The reciprocating pistons 8 are sealed with respect to the wall of the corresponding compression cylinder 7 by three piston rings 15 21 arranged one behind the other, which rest each time in an annular groove arranged in the wall. The piston rings are made of high quality gray cast iron. Alternatively, they can also be made of plastic, in particular Teflon or Peek.

  Between the cylinder head block 6 and the compressor housing 1 is formed a clearly visible concentric slot 22 which is produced by the configuration of the periphery of the cylinder head block 6. The latter (6) is each provided with two ends fronts of a shoulder 23 or 24 formed towards the outside for a sealed application on the compressor casing 1 and between which a concentric recess is formed forming a slot.

  Support surfaces 26 and 27 (Figure 2) are each formed on the cylinder head block 6 for the corresponding shoulder.

  FIG. 2 shows more precisely the configuration of the two shoulders 23 and 24. The annular surface 28 on the front side of the shoulder on the swash plate side 24 is of slightly conical shape because it includes an acute angle of 5 degrees with a plane which extends perpendicularly to the axis of the cylinder head block 6 and thus projects in the axial direction with its outer edge. The shoulder on the valve plate side 23 is generally slightly conical in shape so that its two annular surfaces 29 and 30 include an angle of 4.5 degrees with a plane which extends perpendicularly to the axis of the cylinder head block 6. In the representation of FIG. 2, the cylinder head block 6 is not yet disposed in its predefined final position. When it is introduced into the compressor housing 1, the shoulder 24 first comes to rest with its outer edge on the bearing surface 27 on the side of the swash plate. Following the mounting of the swash plate compressor, which is continued by the insertion of the cylinder liners 7.1 into the compression cylinder 7, the mounting of the valve plate 31, of a seal 32 and the screwing of the valve cover 13, the components mentioned are compressed against each other, the shoulder 24 then being compressed with its outer edge 20 against the bearing surface 27 and, due to its configuration, it is deformed so as to be it also compressed against the bearing surface 26. A connection is thus obtained by geometric engagement and by adhesion. Continuing the screwing, the shoulder 23 is compressed in the same way against the bearing surfaces 27 and 26 on the side of the valve cover so that it is also linked with the compressor housing by engagement. geometric and by adhesion. 15

NOMENCLATURE

  1 Compressor housing 2 Electric motor 3 Drive shaft 4 Crankcase spaceb Swash plate 6 Cylinder head block 7 Compression cylinder 7.1 Cylinder liner 8 Reciprocating piston 9 Suction valve 10 Valve plate 11 Compression chamber 12 Valve exhaust 13 Cylinder head 14 High pressure chamber 15 Oil separator 16 Suction sleeve 17 Closing cover 18 Suction opening 19 Passage opening 20 Intermediate wall 21 Piston ring 22 Slot 23 Shoulder 24 Shoulder 25 26 Surface area '' support 27 Support surface 28 Annular surface 29 Annular surface 30 Annular surface 31 Valve plate 32 Seal L Shark housing support

Claims (5)

  1. Swash plate compressor for vehicle air conditioning equipment, comprising a compressor casing in which is housed a drive shaft 5 provided with a swash plate, which drives at least one reciprocating piston for sucking and compressing a refrigerant , the reciprocating piston being housed in a compression cylinder which is formed in a cylinder head block fixed in the compressor casing and made sealed with respect thereto, a valve plate which closes the compression cylinder and a cover valve which closes the compressor housing, characterized in that between the cylinder head block (6) and the compressor housing (1) is formed a concentric peripheral slot (22) and the cylinder head block (6) rests firmly and tightly on the compressor housing (1) at its two front ends.   2. A swash plate compressor according to claim 1, characterized in that the cylinder head block 20 (6) is provided at its two front ends each time with a shoulder (23, 24) with which it rests tightly on the compressor housing (1).   3. Swash plate compressor according to claim 2, characterized in that the annular surface 25 on the front side (28) of the shoulder on the swash plate side (24) or the two annular surfaces thereof include at the periphery, with a plane perpendicular to the axis of the cylinder head block (6) an acute angle, in particular between 4 and 6 degrees, so that the outer edge projects in the axial direction.   4. Swash plate compressor according to claim 2 and 3, characterized in that the shoulder on the valve plate side (23) is of configuration slightly conical in the same direction and its annular surfaces 35 (29, 30) include in each case at the periphery, with a plane disposed perpendicularly to the axis of the cylinder head block (6), an acute angle which is essentially 0.5 degrees less than the angle of inclination presented by the annular surface ( 28) front side of the shoulder on the swash plate side (24).   5. Swash plate compressor according to claim 1, characterized in that the valve cover (13) is welded with the compressor housing (1).