WO2001065070A2 - Reciprocating piston machine - Google Patents

Abstract

The invention relates to a reciprocating piston machine, in particular to a compressor, preferably for the air conditioning system of a motor vehicle, comprising a housing (1) and a housing cover (3). The working unit (2) which encompasses the pistons (7) is located in the housing (1) and the intake and outlet zone (4, 5) is configured in the housing cover (3), said housing cover (3) being screwed on to the housing (1). The invention is characterised in that to simplify the construction whilst maintaining sufficient impermeability, the screw connection is designed as an individual thread which forms the contact between the housing (1) and the housing cover (3).

Description

 'Reciprocating engine "

The invention relates to a reciprocating piston machine, in particular a compressor, preferably for the air conditioning system of a motor vehicle, with a housing and a housing cover, the working unit comprising the pistons being arranged or formed in the housing and the suction and outlet region being arranged or formed in the housing cover, and the housing cover is screwed to the housing.

Reciprocating machines of the generic type have been known for many years in a wide variety of embodiments and for a wide variety of uses. This can be, for example, a compressor, for example a compressor for the air conditioning system of a motor vehicle. Such compressors are usually referred to as air conditioning compressors and comprise a housing which includes a compressor or pump unit driven from outside. The pump unit, for example designed as an axial piston pump, in turn comprises at least one piston which can be moved back and forth in a cylinder block. Such a compressor is usually equipped with a plurality of pistons, which are moved back and forth when a swash plate is rotated via a receiving plate or when a swivel plate is pivoted in the direction of its longitudinal axis, the receiving plate being mounted in the housing in a rotationally fixed manner in the case of a swash plate. The housing is usually closed off by a housing cover which is screwed or welded to the housing, for example.

Swash plate compressors are known in a wide variety of embodiments. By way of example only, reference is made to DE 44 41 721 A1 and DE 196 11 004 A1.

According to DE 44 41 721 A1, the compressor comprises a swash plate supported on a drive shaft in order to carry out a uniform rotary movement. The swash plate is coupled to a plurality of pistons which can be moved back and forth in a cylinder block, the cylinder-piston arrangement being used to compress one Serves gas. The pistons can also be double-acting pistons.

The generic reciprocating piston machines with screwed or welded housing covers are problematic in practice. The use of tie bolts requires many components, namely screws to be arranged along the circumference. In particular with increased pressure differences, which can occur when using carbon dioxide as a refrigerant, the more screws are required to obtain sufficient strength and tightness. When screwing, it is necessary to secure the necessary axial tension at least largely evenly. Warping when screwing must be avoided. In addition, each housing connection may need its own seal, so that there is an increased number of potential leaks.

If the connection between the housing and the housing cover is a welded connection, the reciprocating piston machine can only be opened with considerable effort and possibly with the destruction of individual components. In this respect, the replacement of parts is no longer possible or only to a limited extent from an economic point of view.

In the light of the foregoing, the present invention is based on the object of designing and developing a reciprocating piston machine of the generic type in such a way that a simple and reversible connection between the housing and the housing cover can be achieved with simple means and with sufficient tightness.

The reciprocating piston machine according to the invention achieves the above object by means of the features of patent claim 1. According to this, the screw connection already implemented in the prior art is of a very special design, namely in the form of a ring nut acting between the housing and the housing cover or a single thread.

According to the invention, it has been recognized that the housing and the housing cover can still be screwed together, but that in the prior art Problems occurring with multiple screw connections can be excluded. This is achieved by using a ring nut which is used with an external thread on the nut and an internal thread on the housing in the area between the housing and the housing cover and is screwed down there in a conventional manner (FIG. 1).

Alternatively, it is possible to use an external thread on the housing cover and an internal thread on the housing (Fig. 2) or a housing cover which is screwed like a union nut over a housing provided with an external thread (Fig. 3).

At this point it should be noted that a screw connection using a ring nut or thread can be implemented regardless of the interior of the reciprocating piston machine. For example, a screw connection with a ring nut or thread with or without internal screwing of the cylinder block / valve plate / pressure cover assembly could take place. In any case, the main focus is on the external seal, which can be easily implemented using a ring nut or thread.

The flow of force in the reciprocating piston machine can be closed by means of a ring nut or thread. In addition, apart from the shaft bushing and the connections, when using the ring nut or an external thread on the cover (FIG. 2), only a single housing seal is required, namely in the area of the ring nut or the external thread.

Another advantage of using a ring nut is that it can be easily welded to the housing and the housing cover - in addition - in a simple manner. It is also possible to replace the ring nut with a welding ring. In addition, the use of a ring nut or a thread, in contrast to numerous tension / anchor screws, leads to a very considerable reduction in weight.

Advantageously, the ring nut can be screwed into the housing on the end face or protrudes into the housing between the housing and a part of the housing cover that projects at least slightly into the housing. Ultimately, that forms Ring nut has an end-side end of the housing projecting beyond the edge of the cover, the housing cover being able to extend in the direction facing away from the housing.

To avoid leakage, it is possible to provide a channel serving as a leakage path, preferably in the form of an annular channel, between the housing and the housing cover directly behind the ring nut or behind the thread. This channel could also serve to relieve pressure in the connection area between the housing and the housing cover.

As already mentioned above, a sufficient seal can be achieved by only a single seal, such a seal being able to be provided between the housing and the housing cover in the area immediately behind the ring nut or the thread. Alternatively or additionally, it is possible for an inner seal to be provided between the housing and the housing cover at a distance from the ring nut or the thread, the inner seal being a circumferential sealing ring. By screwing in the ring nut or the thread, the sealing ring between the housing and the housing cover could be pretensioned, which results in a particularly effective seal.

In order to narrow the tolerance range of the tightening torques, the ring nut or the thread could be provided with a lubricant. It is also conceivable that the ring nut or the thread is preferably coated at least in regions with a polymeric material and may be designed to be self-locking. The ring nut could be made of metal, especially a hardened metal.

There are now various possibilities for designing and developing the teaching of the present invention in an advantageous manner. For this purpose, on the one hand, reference is made to the claims subordinate to claim 1, and on the other hand to the following explanation of exemplary embodiments of the invention with reference to the drawing. In conjunction with the explanation of the preferred embodiments games of the invention with reference to the drawing also generally preferred embodiments and further developments of the teaching are explained. In the drawing shows

1 in a schematic representation, partially, an embodiment of a reciprocating piston machine according to the invention in the form of a reciprocating piston compressor, only the features according to the invention being shown there,

Fig. 2 in a schematic representation, partially and enlarged compared to Fig. 1, another embodiment of a reciprocating piston machine according to the invention, only the interaction between the housing and the housing cover together with seals is shown and

Fig. 3 in a schematic representation, partially and enlarged compared to Fig. 1, again another embodiment of a reciprocating piston machine according to the invention, wherein only the interaction between the housing and the housing cover and seals is shown.

Fig. 1 shows - partially - a compressor for the air conditioning system of a motor vehicle. The compressor comprises a housing 1 and a compression unit 2 arranged in the housing 1 for sucking in and compressing a refrigerant, the refrigerant preferably being CO2.

The refrigerant flows from a suction area 4 formed in a front housing cover 3 through the compressor unit 2 into the outlet area 5 also formed in the housing cover 3.

The compressor unit 2 serves to draw in and compress the refrigerant, the compressor unit 2 comprising pistons 7 running in a cylinder block 6 and a swivel disk driving the pistons 7, which is not shown in the figure. Figure 1 further shows that the housing 1 and the housing cover 3 are screwed together.

According to the invention, the screw connection is designed in the form of an annular nut 8 acting between the housing 1 and the housing cover 3.

The figure further shows that the ring nut 8 can be screwed or screwed into the housing 1 or projecting into the housing 1 between the housing 1 and a part of the housing cover 3 which projects slightly into the housing 1, the ring nut 8 being an external thread and that Housing 1 has an internal thread 12.

Between the housing 1 and the housing cover 3, a channel 9 serving as a leakage path in the form of an annular channel is formed directly behind the ring nut 8. Thereafter, an inner seal is also provided between the housing 1 and the housing cover 3, likewise in the area immediately behind the ring nut 8, this specifically being a circumferential sealing ring 10.

For easier assembly, the groove 11 in the housing cover 3 can be flared upwards to accommodate the ring nut 8. When the ring nut 8 is screwed into the internal thread 12 of the housing 1, the shoulder or the collar 13 of the cover is increasingly pressed against the valve plate 14 and a collar or a shoulder 15 of the cylinder block 6.

The ring nut 8 itself can be coated with a polymeric material or provided with lubricant, as a result of which the tolerance range of the tightening torques can be narrowed. The ring nut 8 is made of metal.

2 shows a further exemplary embodiment of a reciprocating piston machine according to the invention, the interaction of housing 1 and housing cover 3 being shown there - partially and enlarged. Specifically, the housing cover 3 comprises an external thread 16 and the housing 1 an internal thread 12, the external thread 16 and the internal thread 12 interacting. FIG. 2 also shows the structural features already shown in FIG. 1, for example the provision of the seal 10 or the channel 9 forming a leakage path. In this regard, reference is made to the explanations relating to FIG. 1.

FIG. 2 also shows the provision of a fastening screw 17 for fastening the valve block 18 for the control valves not shown in FIG. 2. In addition, it is indicated in FIG. 2 that the suction area 4 is provided with a thermal insulation coating 19.

FIG. 3 likewise shows, in a schematic illustration, partially enlarged compared to FIG. 1, a further exemplary embodiment of a reciprocating piston machine according to the invention, only the interaction between the housing 1 and the housing cover 3 also being shown there. More specifically, a very special housing cover 3 is used there, which is screwed to the housing 1 like a union nut. For this purpose, the housing cover 3 comprises an internal thread 20 which interacts with a partially formed external thread 21 of the housing 1. The housing cover 3 comes into contact with the housing 1 with a clamping shoulder 22. The provision of the clamping shoulder 22 ensures that the housing cover 3 clamps the cylinder block 6 between the housing 1 and the housing cover 3. A seal 23 acts between the cylinder block 6 and the housing 1. With regard to further features, reference is also made to the embodiment of FIG. 1 in order to avoid repetitions.

Finally, it should be emphasized that the exemplary embodiments mentioned above merely by way of example merely explain the teaching according to the invention, but do not restrict it to the exemplary embodiments.

The patent claims submitted with the application are proposals for formulation without prejudice for obtaining further patent patents. The applicant reserves the right to claim further combinations of features previously only disclosed in the description and / or the drawings. Back relationships used in subclaims indicate the further development of the subject matter of the main claim by the features of the respective subclaim; they are not to be understood as a waiver of the achievement of an independent, objective patent for the combinations of features of the related subclaims.

Since the subjects of the subclaims can form their own and independent inventions with regard to the prior art on the priority date, the applicant reserves the right to make them the subject of independent claims or declarations of division. They can furthermore also contain independent inventions which have a design which is independent of the objects of the preceding subclaims.

The exemplary embodiments are not to be understood as a restriction of the invention. Rather, numerous changes and modifications are possible within the scope of the present disclosure, in particular such variants, elements and combinations and / or materials, which, for example, by combining or modifying individual ones in conjunction with and described in and in the general description and embodiments and the claims Features or elements or procedural steps contained in the drawings can be taken by a person skilled in the art with regard to the solution of the task and, by means of combinable features, lead to a new object or to new procedural steps or procedural step sequences, also insofar as they relate to manufacturing, testing and working methods.

Claims

Patent claims 1. Reciprocating piston engine, in particular compressor, preferably for the air conditioning system of a motor vehicle, with a housing and a housing cover, the working unit comprising the pistons being arranged or formed in the housing and the suction and outlet region being arranged in the housing cover and the housing cover having the Housing is screwed, characterized in that the screw connection is designed in the form of a ring nut or a thread acting between the housing and the housing cover. 2. Reciprocating piston engine, in particular according to claim 1, characterized in that the ring nut is preferably screwed on the end face of the housing between the housing and an at least slightly protruding part of the housing cover. 3. Reciprocating engine, in particular according to claim 1 or 2, characterized in that between the housing and the housing cover directly behind the ring nut or the thread, a channel serving as a leakage path, preferably in the form of an annular channel, is provided. 4. reciprocating piston machine, in particular according to one of claims 1 to 3, characterized in that an inner seal is provided between the housing and the housing cover in the area preferably directly behind the ring nut or the thread. 5. Reciprocating engine, in particular according to one of claims 1 to 3, characterized in that an inner seal is provided between the housing and the housing cover, preferably at a distance from the ring nut or the thread. 6. reciprocating piston machine, in particular according to claim 4 or 5, characterized in that the seal is designed as a circumferential sealing ring. 7. Reciprocating piston machine, in particular according to one of claims 1 to 6, characterized in that the ring nut or the thread is provided with a lubricant to reduce the tolerance range of the tightening torques. 8. Reciprocating piston machine, in particular according to one of claims 1 to 7, characterized in that the ring nut or the thread is preferably coated at least in regions with a polymeric material to reduce the tolerance range of the tightening torques. 9. reciprocating piston machine, in particular according to one of claims 1 to 8, characterized in that the ring nut is made of metal. 10. reciprocating piston machine, in particular according to claim 9, characterized in that the ring nut is made of a hardened metal. 11. Reciprocating piston machine, in particular compressor, preferably for the air conditioning system of a motor vehicle, with a housing and a housing cover, the working unit comprising the pistons being arranged or formed in the housing and the suction and outlet region being arranged in the housing cover, and the housing cover having the Housing is screwed, characterized in that the screw connection is designed in the form of a single thread acting between the housing and the housing cover. 12. Reciprocating piston machine, in particular according to claim 1 1, characterized in that the housing cover has an external thread and the housing has an internal thread. 13. reciprocating piston machine, in particular according to claim 1 or 11, characterized in that the housing cover is formed in one piece with the ring nut. 14. Reciprocating piston machine, in particular according to claim 1 or 11, characterized in that the ring nut is integrated in the housing cover. 15. Reciprocating piston machine according to claim 1 or 11, characterized in that the housing cover is designed in the sense of a "union nut" and has an internal thread and that the housing correspondingly has an external thread. 16. Reciprocating engine, in particular compressor, preferably for the air conditioning system of a motor vehicle, with a housing and a housing cover, the working unit comprising the pistons being arranged or formed in the housing and the suction and outlet region in the housing cover, and the housing cover having the Screwed housing, characterized by an inventive feature disclosed in the application documents.