WO1997017545A1

WO1997017545A1 - Helical compressor

Info

Publication number: WO1997017545A1
Application number: PCT/EP1996/004749
Authority: WO
Inventors: Wolfgang SANDKÖTTER; Otfried Schwarzkopf
Original assignee: Bitzer Kühlmaschinenbau Gmbh & Co. Kg
Priority date: 1995-11-06
Filing date: 1996-10-31
Publication date: 1997-05-15
Also published as: WO1997017543A1; EP0859914A1

Abstract

The aim is to improve a compressor comprising the following elements: a helical compressor with a first compressor element and a second compressor element whose helical ribs in the form of circle involutes engage with one another and can move relative to one another in an orbital movement about an axis, a medium to be compressed being taken in on the inlet side, successively compressed in chambers formed between the compressor elements and discharged on the outlet side; a drive motor; and a cam driven by the drive motor for producing the orbital motion of one of the compressor elements, a radial and an axial sealing force being generated between the compressor elements. The improvement is such as to maximise the isentropic total efficiency. To achieve this, it is proposed that a sealing force-generating unit producing the radial sealing force relative to the axis should be provided between the cam and orbiting compressor element, its pressure chamber acted on by a pressurised medium kept under a pressure which is proportional to the outlet-side pressure of the medium to be compressed.

Description

SPIRAL COMPRESSOR

The invention relates to a compressor comprising a scroll compressor with a first compressor body and a second compressor body, the spiral ribs of which are designed in the form of a circular involute and which can be moved relative to one another in a movement orbiting about an axis, with a medium to be compressed being sucked in on the input side between the chambers formed between the compressor bodies is successively compressed and delivered on the output side, a drive motor and an eccentric driven by the drive motor for generating the orbital movement of one of the compressor bodies, a radial and an axial sealing force acting between the compressor bodies.

Such compressors are known for example from US-A-4,781,549 or CN-A-2,063, 232 or 2,060,807.

In these compressors there is generally the problem of sealing between the compressor bodies, these problems occurring particularly in the conditions customary for refrigerant compressors, in particular in the case of large pressure ratios, preferably at pressure ratios of more than approximately 5 to approximately 20, for example. A deterioration in the sealing of the chambers formed between the compressor bodies reduces the volume capacity of the scroll compressor less, but does result in an increase in the shaft power required to drive the scroll compressor and to be applied by the drive motor.

For this reason, the overall isentropic efficiency of such compressors drops.

The invention is therefore based on the object of improving a compressor of the generic type in such a way that the overall isentropic efficiency is as high as possible.

This object is achieved according to the invention in a compressor of the type described in the introduction in that between the eccentric and the orbiting compressor body there is provided a sealing force generating unit which generates radial sealing force to the axis, in the pressure chamber of which a pressure medium acts which acts on the outlet-side pressure of the compressing medium proportional pressure is available.

The solution according to the invention thus not only uses the force resulting from the inertia of the orbiting compressor body to generate the radial sealing force, as is known from the prior art, but also enables a defined pressure for the output of the scroll compressor through the sealing force generating unit to generate proportional additional radial sealing force. In addition to the fact that a far higher sealing force can be generated than is possible with reasonable masses of the orbiting compressor bodies due to the inertial force, this solution has the further advantage that the additional radial sealing force is independent of the rotational frequency of the orbiting In contrast to the use of the inertia known from the prior art, movement is.

A particularly advantageous solution provides that the sealing force generating unit rotates with the eccentric around the axis. This solution has the great advantage that it can be ensured that the sealing force generated by the sealing force generating unit acts exactly in the desired direction, because it is possible to exactly determine the direction of action of the sealing force generated by the sealing force generating unit Align direction of eccentricity.

In the simplest case, the radial sealing force acts exactly in the direction of the eccentricity of the eccentric relative to the axis. In the solution according to the invention, however, it is also possible to define the direction of the sealing force relative to the direction of the eccentricity in a different manner, in order to take account of additional forces acting between the compressor bodies.

A particularly advantageous variant of the solution according to the invention provides that the sealing force generating unit is designed as a double cylinder with two pressure chambers acting counter to one another and that the pressure proportional to the pressure on the outlet side acts in one of the pressure chambers and a reference pressure in the other. This solution opens up the possibility of not only defining the pressure in a pressure chamber as a pressure proportional to the outlet-side pressure, but also the possibility of defining the reference pressure exactly by the sealing force defined by the pressure difference in the two pressure chambers acting against each other not to be subjected to any undefined influences, as would be the case, for example, if no clear reference print were available.

A particularly advantageous solution provides that the reference pressure is a pressure proportional to the pressure on the inlet side. With this solution, the radial sealing force can be matched in a particularly suitable manner to the pressures counteracting the seal between the compressor bodies, namely the outlet-side pressure and the inlet-side pressure, since the sealing force is thereby both due to the inlet-side pressure and to the outlet ¬ side pressure is defined proportional pressure and thus always adjusts itself so that it fully takes into account the forces counteracting a seal by these pressures.

The sealing force generating unit can in principle be designed in a wide variety of ways. A particularly advantageous exemplary embodiment provides that the sealing force generating unit has an inner body and an outer body, which are displaceable relative to one another and one of which is seated on the eccentric pin in a rotationally fixed manner. The sealing force generating unit preferably comprises an inner body and an outer body which is displaceable in one direction with respect to this, the inner body being seated in a rotationally fixed manner on the eccentric pin. In this solution, the direction in which the radial sealing force acts can be precisely determined by the displaceability of the outer body relative to the inner body, since, on the other hand, the inner body is seated on the eccentric pin in a rotationally fixed manner and can therefore be exactly aligned relative to the eccentricity.

No further statements have so far been made with regard to the action of the outer body of the sealing force generating unit on the orbiting compressor body. An advantageous exemplary embodiment provides that the outer body acts on the movable compressor body via a rotary bearing. This ensures that the entire sealing force generating unit also rotates with the eccentric pin and, on the other hand, the movable compressor body carries out an essentially orbital movement, preferably fixed by a so-called Oldham coupling.

A particularly advantageous embodiment of the sealing force generating unit according to the invention provides that the pressure difference between the pressure chambers acts on the outer body relative to the inner body radially to the axis and in the direction of the eccentricity of the eccentric.

In the context of the previous explanation of the pressure force generating unit, it was not discussed in detail how the pressure space can advantageously be acted upon by the pressure proportional to the outlet-side pressure, in particular when the sealing force generating unit sits rotatably on the eccentric and rotates with it. Thus, an advantageous solution provides that a pressure line leads to the pressure chamber under the pressure on the outlet side, through the eccentric, and preferably also through the shaft carrying the eccentric, which opens up the possibility of the pressure line via a shaft surrounding the shaft To supply ring groove.

Within the scope of the exemplary embodiments of the solution according to the invention explained so far, no further details are given as to how the axial sealing force which acts on the compressor bodies against one another is generated. An advantageous exemplary embodiment provides that one of the compressor bodies is acted upon in the direction of the other by a medium whose pressure is proportional to the pressure on the outlet side.

This is preferably done in the case of the compressor body which performs the orbiting movement, so that there is the possibility of arranging one of the compressor bodies in a stationary manner in a housing of the compressor, while the other compressor body orbits on the one hand and thus the axial sealing force as well as the radial sealing force due to the sealing force generating unit according to the invention.

The axial sealing force can be generated particularly expediently if an axial pressure chamber is arranged above a rear end face of the compressor body, in which the pressure proportional to the pressure on the outlet side can then be generated. This axial pressure chamber can advantageously be implemented in that it has a sealing ring which can be displaced telescopically in the axial direction and which follows the movement of the compressor body in the axial direction.

This sealing ring is preferably spring-loaded in the axial direction, in order to enable the same to rest securely in all axial positions.

A particularly advantageous solution provides that the sealing force generating unit is arranged within the axial pressure chamber, which creates a particularly compact solution.

The solutions according to the invention, in which the radial sealing force and / or the axial sealing force are generated in each case by means of a pressure proportional to the pressure on the outlet side, not only have the advantage, as already described in detail, that a definable sealing force is available to relate the compressor body relatively to hold each other sealing positions. These solutions in particular also have the great advantage that, should an overpressure occur in the scroll compressor, for example due to over-compression in the scroll compressor, the relative mobility between the compressor bodies, which is necessary to adjust the radial sealing force and / or the To allow axial sealing force to take effect, opens up the possibility that the seal between the two compressor bodies can be intentionally removed for a short time in order to compensate for the excess pressure which builds up as a result of overcompression Compensation of such an overpressure can be precisely determined by the fact that the effective radial and / or axial sealing forces can be precisely determined, which then represent a threshold in the event that overpressure arises in the chambers formed between the compressor bodies.

The suitability of the solution according to the invention described above for pressure ratios of 5 to 20 is improved in particular in that an inner end of at least one spiral rib is thickened, since this solution opens up the possibility of precisely defining the final volume during compression and thus also the output side To set the pressure exactly without having to run the spiral ribs up to the beginning of the circular involute, which would in particular raise production problems with regard to the shapes to be produced. The inner thickened end of at least one of the spiral ribs opens up the possibility of leaving the involute shape near the end due to the thickened shape.

Such thickened ends can be designed in a wide variety of ways, for example US-A-4,781,549 describes a type of formation of such thickened ends. Further types of formation of such thickened ends can be found in US-A-3,802,809. EP-A-0 122 722, US-A-4, 547, 137 and US-A-4, 558, 997.

Both spiral ribs are preferably formed with a thickened inner end, the thickened ends in particular having identical shapes. A particularly preferred variant of the solution according to the invention provides that the spiral ribs are designed in such a way that in the region of the thickened ends the two chambers forming on the input side between the spiral ribs unite to form a chamber which is reduced to a residual volume between the ends. This solution according to the invention has the great advantage that, in contrast to some solutions known from the prior art, the thickened ends do not aim to ultimately reduce the size of one chamber formed between them to a volume which theoretically is one Corresponds to zero volume, but despite the thickened ends a residual volume between them is deliberately sought, which corresponds to the smallest volume of the chamber which arises when the spiral ribs of the two compressor bodies are still sealingly adjacent to one another, immediately before the ends of the spiral ribs lift off from each other and the two combine the following chambers with the chamber reduced to the remaining volume in order to reduce the common volume to the remaining volume in the further orbiting movement.

This solution has the great advantage that it avoids leaks between the compressor bodies, which result from the fact that, during the last compression cycle, an overpressure occurs in one chamber located between the ends, which leads to the compressor bodies being relatively relative to one another move and the seal of all the chambers formed between the spiral ribs is reduced. Such an overpressure not only has to occur in that it occurs in the medium to be compressed, it can also be carried out in that liquid or oil is conveyed into the medium to be compressed, which occurs when a volume is sought Zero cannot be displaced quickly enough between the thickened ends, that is to say not as quickly as the preferably gaseous medium to be compressed, and thus counteracts the achievement of the end volume, which theoretically becomes zero, by the thickened ends not meeting one another quickly enough to be able to move. In this case, the above-described reduction in the sealing between all the chambers formed between the spiral ribs then occurs.

A particularly advantageous solution provides that the residual volume extends at least over a cross section of an outlet opening, and thus in particular also serves to provide a sufficient cross section for displaced gas in order to reach the outlet opening.

A particularly preferred embodiment of the solution according to the invention provides that the outlet opening lies outside a region of the bottom surface of the stationary compressor body which is covered by the end of the orbiting spiral rib. This solution according to the invention has the great advantage that with this arrangement of the outlet opening it is possible to deviate from the previously known working principles of the spiral compressor insofar as an outflow of the compressed medium, in particular the compressed gas medium, no longer from the position of the end of the orbiting spiral rib is dependent and thus the resulting path control of the exit of the medium to be compressed by the orbiting movement is omitted. The outlet cross section of compressed medium can thus be controlled completely independently of the orbiting movement. This solution thus opens up the possibility of determining the outlet conditions for the compressed medium completely independently of the orbiting movement.

As an alternative or in addition to the solutions described above in a compressor of the type described in the introduction, the object according to the invention is also achieved according to the invention in that one of the compressor bodies has a spiral rib with an outlet channel lying in the region of the inner end, in which one in a wall of the The end of the outlet opening opens. This solution according to the invention has the great advantage that it opens up a completely new type of outlet of the compressed medium, in particular of the compressed gaseous medium, because by arranging the outlet opening in the wall of the end of the spiral rib, the outlet opening is removed from the The floor surface of one compressor body is moved away and the control of the outlet cross-section and also of the outlet as a whole by the orbiting movement is thus eliminated. In addition, this arrangement of the outlet creates the possibility of allowing the medium to be compressed to emerge under optimal spatial conditions, in particular when the spiral ribs are high, because the medium to be compressed does not have to exceed the maximum at the outlet entire height of the spiral ribs flow to the outlet opening arranged in a bottom surface of a compressor body, but the maximum path that the compressed medium has to travel can be reduced to a fraction of the maximum height of the spiral rib in a simple manner. This also opens up the possibility of improving the overall isentropic efficiency of a compressor according to the invention, since this also avoids the effects of the medium to be compressed that remove the seals between the chambers during final compression, which occur in particular in all the solutions in which the a chamber forming between the ends is compressed to a volume which is insignificantly above zero, since with such a small volume the last compressed medium still flowing out of the chamber no longer has a sufficiently large cross-section.

It is particularly advantageous if the outlet opening opening into the outlet channel, viewed in the direction of the axis, is arranged in a central region of the wall, since this ensures that the maximum distance that the compressed medium has to travel when it flows out is a maximum of half the height of the spiral rib or half the extent of the spiral rib in the direction of the axis.

With regard to the type of outlet channel to be provided in the end of the spiral rib, no further details have been given in connection with the solutions described so far. It is particularly advantageous if the outlet channel is formed by a cavity in the end of the spiral rib, this cavity preferably providing a flow cross section which is larger than the flow cross section provided by the outlet opening, so that the compressed medium only has to flow through the outlet opening as a flow-preventing element, but then again the largest possible flow cross-section is found which does not hinder the outflow of the compressed medium from the one chamber formed between the ends.

It is also particularly expedient if a guide pocket surrounding the outlet opening is provided in the spiral rib having the outlet opening. The guide pocket serves in particular to guide the compressed medium flowing to the outlet opening to the outlet opening with as little deflection as possible and with as little turbulence as possible. In addition, the guide pocket easily creates the possibility of providing a residual volume between the ends of the spiral ribs, so that the advantages already described above can also be achieved hereby.

A particularly expedient solution provides that the guide pocket is arranged at the end of the spiral rib in such a way that in an end position of the orbital movement the spiral rib of the other compressor body rests sealingly with its end on both sides of the guide pocket in linear areas. With this solution it is ensured that the guide pocket forms at least part of the remaining volume and is thus available in its full cross-section in the end position of the orbiting movement, in which the highest compression of the medium to be compressed is achieved, around the compressed medium to the outlet opening respectively.

A further solution is particularly advantageous, in which each of the ends has a guide pocket and these are arranged opposite one another in the end position. Another embodiment of a solution according to the invention, in particular a further development of the solution, in which the outlet opening lies outside the area of the bottom surface of the stationary compressor body which is covered by the end of the orbiting spiral rib, provides that an outlet valve is assigned to the outlet opening. This makes it possible to control the outflow of the compressed medium in a defined manner.

This control could take place, for example, via a valve controlled by a control, the control being able to determine control times according to different parameters.

A particularly advantageous embodiment, however, provides that the outlet valve is pressure controlled. This simple solution opens up the possibility of making the outflow of the compressed medium dependent on the pressure reached and thus of being able to open the outlet opening and subsequently close it accordingly, independently of the orbital movement when the desired pressure is reached .

A particularly direct valve action can be achieved if the outlet valve overlaps the outlet opening with a valve body and is thus directly assigned to the outlet opening. In the case of an outlet opening arranged in the wall of the thickened end, this requires the outlet valve to be arranged such that it projects at least with the valve body overlapping the outlet opening into the outlet channel or the cavity in the end. When providing such a pressure-controlled outlet valve, it is also necessary to provide an anchoring element of the valve. It is possible to arrange this anchoring element of the valve in the outlet channel in the end of the spiral rib. In this case, the entire outlet valve is advantageously arranged in the cavity of the end of the spiral rib.

However, in order to create advantageous conditions especially for maintenance and assembly, an alternative solution provides that the anchoring element of the outlet valve is arranged outside the outlet channel in the end of the spiral rib and sits, for example, over a rear end face of the compressor body carrying the outlet opening.

Further features and advantages of the solution according to the invention are the subject of the following description and the drawing of some exemplary embodiments.

The drawing shows:

1 shows a longitudinal section through a scroll compressor according to the invention;

FIG. 2 shows a detail of the area around FIG. 1 around the sealing force generating unit; FIG.

Fig. 3 is a section along line 3-3 in Fig. 1;

Fig. 4 is a section along line 4-4 in Fig. 1; Fig. 5 is a section along line 5-5 in Fig. 1;

6 shows a detail of a first exemplary embodiment of thickened ends of spiral ribs;

7 shows a detail of a second exemplary embodiment of thickened ends of the spiral ribs;

8 shows a detail of a third exemplary embodiment of thickened ends of the spiral ribs and

9 shows a section along line 9-9 in FIG. 8.

An embodiment of a compressor according to the invention, in particular a refrigerant compressor for normal and deep-freezing, preferably operating at pressure ratios of approximately 5 to approximately 20, shown in FIG. 1, comprises a housing, designated as a whole by 10, in which a drive motor 12 is mounted.

The drive motor 12 comprises a stator 14 and a rotor 18 rotatable about an axis 16, which is rotatably mounted on both sides of the stator 14 by means of bearings 20 and 22 in a bearing plate 24 and 26 arranged in the interior of the housing 10. On one side of the bearing 22 facing away from the stator 14 there is arranged an eccentric gear, designated as a whole by 30, which comprises an eccentric pin 34 arranged eccentrically with respect to the axis 16 on a shaft 32 of the rotor 18, which in turn is designed as a sealing force generating unit Eccentric bearing 36 engages, which in turn acts via an eccentric bearing receptacle 38 on a compressor body 42 which can be moved in an orbiting manner relative to a stationary compressor body 40. In this case, the stationary compressor body 40 is fixedly arranged in the housing 10 and extends over an entire cross section thereof transverse to the axis 16. Between the stationary compressor body 40 and a front housing cover 44 there is an outlet pressure chamber 46 in which the one to be compressed Medium with outlet pressure is present.

The outlet pressure chamber 46 is connected via a longitudinal channel 48 passing through an outer region of the stationary compressor body 40 to a motor chamber 50 receiving the drive motor 12, the motor chamber 50 also being under outlet pressure.

It is preferably provided that when the housing 10 is arranged with the axis 16 lying, an oil sump 52 of lubricating oil is formed therein, the longitudinal channel 48 likewise being located in the oil sump 52.

From the oil sump 52, an oil channel 54 leads to the bearing 22 in the bearing plate 26 and opens there into an annular channel 56 surrounding a supported section 58 of the shaft 32, so that the lubricating oil passes from the annular channel 56 into an annular channel 62 in the section 58 of the shaft 32 can. From this ring channel 62, a branch channel 64 running radially to the axis 16 leads into an interior of the shaft 32, merges there into a longitudinal channel 66 running towards the eccentric pin 34, from which in turn a radial branch channel 68 in the eccentric pin 34 leads to an opening 70 leads in an outer peripheral surface 72 of the eccentric pin 34.

As shown in FIGS. 2 and 3, the eccentric bearing 36 designed as a sealing force generating unit comprises an inner body 80 which is provided with a receptacle 82 for the eccentric pin 34 designed as a mating surface for the outer peripheral surface 72 of the eccentric pin 34. The inner body 80 is fixed in a rotationally fixed manner on the eccentric pin 34 by means of a wedge 84.

Two pistons 86 and 88 are firmly connected to the inner body 80, preferably integrally formed thereon, in which a puncture channel 90, which is aligned with the puncture channel 68 and continues in the latter beyond the mouth opening 70, is provided in the piston 86, which in turn has a Mouth opening 92 ends in a piston crown 94.

Both pistons 86 and 88 each lie in a cylinder chamber 96 and 98, both of which are arranged in an outer part 100 of the eccentric bearing 36. Thus, the piston 86 delimits a pressure chamber 102 in the cylinder chamber 96, while the piston 88 delimits a pressure chamber 104 in the cylinder chamber 98, the outer part 100 being displaced relative to the inner part 80 in accordance with the pressure difference in the pressure chambers 102 and 104. Furthermore, the inner part 80 is preferably guided via guide surfaces 109 and 111 running parallel to a direction of movement 106 of the pistons 86 and 88 on corresponding guide surfaces 113 and 115 in the outer part 100, the guide surfaces 109 and 111 being arranged on both sides of the receptacle 82.

As shown in FIG. 2, an axial pressure channel 108 leads from the pressure chamber 102 into an annular space 110, from which a throttle channel 112 leads to the pressure chamber 104 in the area of the pressure chamber 104. Furthermore, a pressure compensation channel 114 leads from the pressure chamber 104 into a low-pressure chamber 116 located on the end face of the eccentric bearing 36, which in turn is connected to a low-pressure channel 118 which runs transversely to the axis 16 through the compressor body 42 ₍ for example, via axial Stick channels 120 is connected to a radially outer suction side of the two compressor bodies 40, 42 which is under inlet pressure.

Lubricating oil is now pressed out of the oil sump 52 through the oil channel 34 via the ring channels 56 and 62, the channels 64, 66 and 68 and the channel 90 into the pressure chamber 102, so that there is also output pressure in this. Furthermore, the oil has the possibility of entering the pressure chamber 104 via the axial channel 108, the ring channel 110 and the throttle channel 112, the throttle channel 112 reducing the pressure, for example to a low pressure level which is slightly above the inlet pressure but appreciably below the Output pressure is so that the oil from the pressure chamber 104 via the pressure equalization channel 114, the Low-pressure chamber 116, the low-pressure duct 118 and the branch duct 120 are injected between the compressor bodies on the inlet side for lubrication.

At the same time, due to the pressure difference between the pressure chamber 102 and the pressure chamber 104, a force is exerted on the outer part 100 such that it moves away from the piston 86 in the direction 106.

The piston 86 is arranged in such a way that the direction 106 corresponds to the direction of the eccentricity of the eccentric pin 34 relative to the shaft 32, so that the outer part 100, which is rotated together with the inner part 80 by the eccentric pin 34, always with an in Direction 106 of the eccentricity force acts on the eccentric bearing receptacle 38.

In order to enable rotation of the outer part 100 together with the inner part 80 and the eccentric pin 34 relative to the eccentric bearing receptacle 38, the outer part 100 is surrounded by a bearing ring 122, which rotates the eccentric bearing 36 in the eccentric bearing receptacle 38 about an eccentric bearing axis 124 allowed.

The eccentric axis 124 moves on a circular arc around the axis 16, so that the orbiting compressor body 42 carrying the eccentric bearing mount 38 moves orbiting around the axis 16 in accordance with this circular path, the compressor body 42 being rotatable relative to the oldham coupling 126 by means of an orbiting movement stationary compressor body 40 is guided. Furthermore, the orbiting compressor body 42 is movable in the direction of the axis 16 and is therefore subjected to an axial force in the direction of the stationary compressor body 40. This force is achieved by applying an outlet pressure to an inner region 130 which comprises the eccentric bearing receptacle 38 with the eccentric bearing 36. This inner region 130 is separated from an outer region 132 by an axial ring seal 134 which has a sealing ring 136 which can be displaced in the direction of the axis 16 and which is acted upon by a spring assembly 138 in the direction of a rear end face 140 of the orbiting compressor body 42 and also one on the front Bearing plate 26 molded guide ring 146 engages sealingly in the radial direction, the guide ring 146 also serves to guide the sealing ring 136 in the axial direction. The sealing ring 136 is preferably also provided with a radially narrower bearing ring 144 which in turn rests on the rear end face 140 of the orbiting compressor body 42.

The spring assembly 138 is also preferably guided through the guide ring 146 and is supported on a flange surface 142 of the front bearing plate 26.

The front bearing plate, which carries the guide ring 146, forms an axial pressure chamber 148 which lies above the inner region 130 and which is connected to the motor chamber 50 by means of a connecting channel 149, so that the initial pressure is thus present. The outer area 132 of the orbiting compressor body 42 lying outside the sealing ring 136 lies in an inlet pressure chamber 150 which is also formed by the front bearing plate and into which an inlet nozzle 152 opens. The inlet pressure chamber 150 is also connected to an outer side of the compressor bodies 40 and 42.

The two compressor bodies 40 and 42 are each provided with a spiral rib 160 or 162, which rise above a bottom surface 164 or 166 of the respective compressor body 40 or 42, and each have an outer wall surface 168a or 170a and one have inner wall surfaces 168b and 170b, which rise from the respective floor surfaces 164 and 166, which run perpendicular to the axis 16, parallel to the direction of the axis 16 over a height of preferably more than 30 mm and also run along a circular involute , which lies in a plane parallel to the bottom surface 164 or 166.

The spiral-shaped ribs 160 and 162 can be placed against one another by the orbitalizing movement of the movable compressor body 42 relative to the stationary compressor body 40 with their rib wall surfaces 168a and 168b or 170a and 170b, crescent-shaped chambers 172 and 174 being formed between them which the medium to be compressed is conveyed from a radially outer inlet area 176 to a radially inner outlet area 178 and is compressed in the process.

These chambers 172 and 174 merge into a single chamber 179 before reaching the outlet area 178. Such scroll compressors are described in detail, for example, in the article "Scroll Compressor Design and Application Characteristics for Air Conditioning, Heat Pump and Refrigeration Applications, by JPElson, GF Hundi and KJ Moniet, published in the journal Proceedings of the Institute of Refrigeration, Session 1990-1991, page 2-1 to 2-10 or U.S. Patent 4,781,549, which are incorporated by reference.

As shown in FIGS. 5 and 6, the spirally shaped ribs 160 and 162 are provided with thickened radially inner ends 180, 182, with which there is the possibility of compressing the medium to be compressed as high as possible without the spiral ribs 160 and 162 must be guided as close as possible to the base circle of the involute. The configuration of such thickened ends 180 and 182 is described, for example, in EP-A-0 122 722, US-A-4,547,137, and US Pat. No. 4,558,997 or US Pat. No. 4,781,549.

According to the invention, in the solution shown in FIG. 6, the thickened end 180 of the spiral rib 160 has an inner cavity 184 which, as shown in FIG. 1, thickened from an opening 188 in a rear end face 186 of the stationary compressor body 40 End 180 of the rib 160 extends into it and is preferably closed toward the orbiting compressor body 42.

An outlet opening 190 opens into this cavity 184, which is arranged in a wall 192 of the thickened end 180 of the rib 160 facing the thickened end 182, specifically in relation to the extent of the wall 192 in the direction parallel to the axis 16 in an approximately central region, so that the outlet opening 190 lies in a surface parallel to the axis 16 and enables the compressed medium to escape in the radial direction to the axis 16.

Furthermore, the wall 192 is provided with an inner contour facing the end 182 which, on the one hand, in an end position of the orbiting movement of the orbiting compressor body 42 shown in FIG. 6, relative to the stationary compressor body, in which the ends 180 and 182 just abut one another and still do not lift off, form two linear regions 194 and 196, in which a wall 198 of the thickened end 182 faces the wall 192, and also form a guide pocket 200 between these linear regions 194 and 196, the inner contour 204 of which is linear relative to a connecting straight line 201 between these Areas 194 and 196 set back extend into the wall 192 opposite the connecting straight line 201 and merge into the outlet opening 190 in the area of their greatest distance from the connecting straight line 201. Furthermore, the guide pocket extends in the direction of the linear regions 194 and 196 beyond the outlet opening 190 and its inner contour 204 gradually approaches the connecting straight line 201 with increasing proximity to the linear regions 194 and 196.

The inner contour 204 of the guide pocket 200 is preferably formed in an arcuate cross-section lying between the line-shaped regions 194 and 196, the connecting straight line 201 forming an arch chord. This guide pocket 200 serves, on the one hand, to guide the compressed medium present between the walls 192 and 198 as closely as possible and as short as possible to the outlet opening 190 when the ends 180 and 182 approach each other, and on the other hand to ensure that in the end position described above ends 180 and 182 have a noticeably large space relative to one another for receiving displaced oil or displaced liquefied medium, and in this end position between ends 180 and 182 there is just no residual volume approaching zero, as is the case in US-A -4,781, 549 is sought.

The inner contour 204 of the guide pocket 200 is preferably also arched in cross-section in the direction of the axis 16, so that it has a deepest area 206, into which the outlet opening 190 opens.

In the first exemplary embodiment shown in FIG. 6, the wall 198 of the thickened end 182 has an inner contour 208 which extends essentially straight between the linear contact areas 194 and 196 in the end position and which essentially approximates the connecting straight line 201 is.

In contrast to the solution shown in FIG. 6, an even more advantageous embodiment of the solution according to the invention, shown in FIG. 7, also has a guide pocket 202 in the wall 198, which in the described end position of the ends 180 and 182 of the guide pocket 200 is exactly opposite and is also formed with its inner contour 208 'in an arc shape with respect to the connecting straight line 201. By means of these two guide pockets 200 and 202 lying opposite one another it is achieved that in the end position of the orbiting movement in the area opposite the outlet opening 190 they provide a sufficiently large gas flow cross-section for the outflowing gas in order to make this gas possible to flow optimally to the outlet opening 190 and also to form a significant space for receiving displaced oil or displaced liquefied medium, the largest accumulation of displaced oil or liquefied medium being formed near the outlet opening 190.

As shown in both FIGS. 6 and 7, the outlet opening 190 is provided with a pressure-controlled outlet valve 210, which in the exemplary embodiment shown has a lamella 212 provided with a front flexible area 211, the opening movement of which is limited by a catch 214 is. The lamella 212 and catcher 214 are anchored, for example, with an anchoring element 216, for example a screw, in the wall 192, preferably in a thickened region 218 opposite the guide pocket 200 with respect to the linear region 194.

The lamella 212 in turn lies against a wall surface 220 of the cavity 184 in the region of the wall 192, the front region 211 of the lamella 212 engaging over the outlet opening 190 in the region of its confluence with the cavity 184.

Alternatively, it is possible to provide another pressure-controllable valve, for example a plate valve, instead of the lamella valve. In a third exemplary embodiment, shown in FIGS. 8 and 9, the lamella valve 210 'is arranged such that the lamella 212 with its front region 211 also abuts the outlet opening 190 in the cavity 184 on the wall surface 220. However, as shown in FIG. 9, the lamella 212 extends from its front area 211 in the direction of the rear end face 186 of the compressor body 40 and out of the opening 188 and the anchoring element 216, which overlaps one at the rear the protrusion 222 engaging the end face 186 engages so that the anchoring element 216 is freely accessible above the rear side 186, whereby assembly of the lamella valve 210 'is facilitated. The catcher 214 extends in the same way as the slats 212, so that the slats 212 and catcher 214 only protrude with their front regions through the opening 188 into the cavity 184 and are therefore easy to assemble.

Claims

PATENT CLAIMS

1. Compressor comprising a scroll compressor with a first compressor body and a second compressor body, the spiral ribs of which are designed in the form of a circular involute and which can be moved relative to one another in an orbital motion about an axis, a medium to be compressed being sucked in on the input side, in between the compressor bodies The chambers formed are successively compressed and released on the output side, a drive motor and an eccentric driven by the drive motor for generating the orbital movement of one of the compressor bodies, a radial and an axial sealing force acting between the compressor bodies, characterized in that between the eccentric (34) and the orbiting compressor body (42) there is provided a sealing force generating unit (36) that generates the radial sealing force to the axis (16), in the pressure chamber (102) of which a pressure medium acts, one of which acts on the outlet side n The pressure of the medium to be compressed is proportional.

2. Compressor according to claim 1, characterized in that the sealing force generating unit (36) rotates with the eccentric (34) and the axis (16).

3. Compressor according to claim 1 or 2, characterized gekenn¬ characterized in that the sealing force generating unit (36) is designed as a double cylinder with two counteracting pressure chambers (102, 104) and that in one of the pressure chambers (102, 104) to the output side Pressure proportional pressure acts and in the other a reference pressure.

4- compressor according to claim Z, characterized in that the reference pressure is a pressure proportional to the outlet pressure.

5. Compressor according to one of the preceding claims, characterized in that the sealing force generating unit (36) has an inner body (80) and an outer body (100) which are displaceable relative to one another in one direction and in that one of them rotatably on the eccentric pin ( 34) sits.

6. A compressor according to claim 5, characterized in that the outer body (100) acts on the movable compressor body (42) via a rotary bearing (122).

7. A compressor according to claim 5 or 6, characterized gekenn¬ characterized in that due to the pressure difference between the pressure spaces (102, 104) of the outer body (100) relative to the inner body (80) radially to the axis (16) and in the direction of the eccentricity of the eccentric (34) with the radial sealing force.

8. Compressor according to one of the preceding claims, characterized in that a pressure line (64, 66, 68) leads to the pressure chamber (102) under the outlet-side pressure proportional pressure (102) through the eccentric (34).

9. Compressor according to one of the preceding claims, characterized in that one of the compressor bodies

(42) aj.ial in

the other (4.0)

a pressure is applied, the pressure of which is proportional to the pressure on the outlet side.

10. A compressor according to claim 9, characterized in that an axial pressure chamber (148) is arranged over a rear end face (140) of the compressor body (42).

11. A compressor according to claim 10, characterized in that the axial pressure chamber (148) has a sealing ring (136) which is telescopically displaceable in the axial direction.

12. A compressor according to claim 11, characterized in that the sealing ring (136) is spring-loaded in the axial direction.

13. Compressor according to one of claims 10 to 12, characterized in that the sealing force generating unit (36) is arranged within the axial pressure chamber (148).

14. Compressor according to one of the preceding claims, characterized in that an inner end (180, 182) at least one of the spiral ribs (160, 162) are formed thickened.

15. A compressor according to claim 14, characterized in that the spiral ribs (160, 162) are designed such that in the region of the ends (180, 182) the two chambers (172, 172) forming on the input side between the spiral ribs (160, 162) 174) to form a chamber (179) which is reduced between the ends (180, 182) to a residual volume (200, 202).

16. A compressor according to claim 15, characterized in that the residual volume (200, 202) extends at least over a cross section of an outlet opening (190).

17. Compressor according to one of the preceding claims, characterized in that the outlet opening (190) lies outside a region of the bottom surface (164) of the stationary compressor body (40) which is swept by the end (182) of the orbiting spiral rib (162).

18. Compressor according to the preamble of claim 1 or according to one of the preceding claims, characterized gekenn¬ characterized in that one of the compressor elements (40, 42) has a spiral rib (160, 162) with one in the region of the inner end (180, 182) Has outlet channel (184), in which an outlet opening (190) lying in a wall (192) of the end (180) opens.

19. A compressor according to claim 18, characterized in that the outlet opening (190) opening into the outlet channel (184) is arranged in the direction of the axis (16) in a central region of the wall (192).

20. A compressor according to claim 18 or 19 characterized gekenn¬ characterized in that the outlet channel is formed by a cavity (184) in the end (180) of the spiral rib (160).

21. Compressor according to one of claims 18 to 20, characterized in that a guide pocket (200) surrounding the outlet opening (190) is provided in the spiral rib (160) which has the outlet opening (190).

22. Compressor according to one of claims 18 to 21, characterized in that the guide pocket (200) is arranged at the end (180) of the spiral rib (160) in such a way that the spiral rib (162) of the the other compressor body (42) with its end (182) on both sides of the guide pocket (200) in line-shaped areas (194, 196) sealingly.

23. Compressor according to one of the preceding claims, characterized in that the outlet opening (190) is associated with an outlet valve (210).

24. A compressor according to claim 23, characterized in that the outlet valve (210) is pressure controlled.

25. A compressor according to claim 24, characterized in that the outlet valve (210) overlaps the outlet opening (190) with a valve body (212).

26. A compressor according to claim 25, characterized in that an anchoring element (216) of the valve (210) in the outlet channel (184) in the end (180) of the spiral rib (160) is arranged.

27. A compressor according to claim 25, characterized in that the anchoring element (218) is arranged outside the outlet channel (184).