EP0804684B1 - Compressor - Google Patents

Description

The invention relates to a compressor for the compression of a working medium, in particular for production of compressed air, with at least one in a work area reciprocating piston to compress the Working medium, a drive device for reciprocation of the piston and with a feed device and a discharge device for supplying or removing the working medium, a crank loop drive being provided as the drive device.

Compressible substances such as gases are used as working media or vapors are used in conventional compressors mostly air is compressed. This compressed air is e.g. in trucks as a means of transmission in braking devices used.

There are a variety of plunger compressors with Crank-connecting rod drive known. These compressors work on the principle of the crank mechanism and usually have an oil lubrication. Due to the swinging movement of the Connecting rods make it difficult for these compressors to enter the work area to seal against the crankcase. Therefore came Oil leakage past the piston rings into the work area and leads to oil coking, especially at the outlet valve. As a countermeasure to this are in the conventional compressors Cooling devices necessary. With these the Reduced air and component temperature and thus that too Degree of oil coking reduced. The need for one Cooling, which is usually carried out as water or air cooling is, but requires considerable design effort and a large space requirement.

The design effort increases further from the Need to heat the intake air through to avoid the compressed air to be discharged. The warmer the air sucked in, the lower the delivery rate the compressor due to the increase in temperature accompanying volume expansion of the working medium. Therefore the greatest possible structural separation of the feed and Leakage lines for the working medium are sought.

Another disadvantage of conventional compressors with these single-stage compressors is the low delivery rate. This is due to the re-expanding damage volume from the dead spaces, the high intake valve resistances because of the necessary pressure stability of the valve and the Heating of the air through the also in the cylinder head hot exhaust air limited.

The conventional plunger compressors with crank-connecting rod drive therefore require a considerable constructive Effort, a variety of components and a large one Space requirements. Furthermore, e.g. a change of location of the Inlet connection usually a complete constructive redesign of the compressor, since the piping of the inlet and the outlet pipes and the cooling pipes precisely matched due to the heat development have to be.

It is already known in the state of the art, crank loop drives to use for internal combustion engines. So shows e.g. DE 32 18 311 C2 a crank loop drive, especially for a two-stroke internal combustion engine is provided which is operational even without oil lubrication is. Furthermore, DE 34 47 663 A1 describes a multi-cylinder internal combustion engine known in the implementation in a rotary motion by means of a crank loop drive he follows. Another embodiment of such a crank loop drive is described in DE 43 07 205 A1. Regarding the exact functional principle and regarding the operation of the crank loop drive can therefore full reference to the publications mentioned become.

The crank loop drive offers the advantage that that the rotary motion of a crankshaft in a purely longitudinal motion the piston is converted. This enables one secure sealing of the sliding surface between the piston skirt and the bearing in the compressor block. If appropriate the teaching of DE-A-2 033 820, FR-A-364091 or BE-A-861533 a crank loop drive is provided as the drive device of the compressor, can be ensured that the work area opposite the crankcase is always adequately sealed, which has the decisive advantage that the work space used on both sides of the piston for the compression process and that no oil particles get into the work area can.

This will cause coking of the valves, in particular of the exhaust valve, avoided and it can on cooling to be dispensed with. The considerable design effort The design of the course of the cooling channels is therefore not necessary completely and the design is significantly simplified.

Compared to the generic BE-A-861 533, the object of the invention is to create a compressor in which the working space can be sealed in a simple manner. The invention solves this problem by the subject matter of claim 1.

The workspace can be specified in claim 2 Development of the invention on both sides of the piston on the one hand as a pre-compression space and on the other hand as Serve the main compression space, i.e. the piston movement can e.g. serve as an ejection movement and at the same time for suction of still uncompressed working fluid on the rear of the piston.

This results in a two-stage compressor that Working medium first compressed and then in emits a main compression stroke. While the conventional single-stage compressor due to component tolerances and the thermal expansion occurring dead volume Degree of delivery deteriorated significantly, is for the two-tier Compressor the work of the dead volume almost insignificant, because the back expansion of the working medium there is direct is used for pre-compression.

The compression energy introduced into the dead volume is therefore not lost and therefore enables a significant higher efficiency or delivery rate. With a such an arrangement can e.g. the degree of delivery versus 55% with a conventional series compressor to 80% with Raise the crank loop compressor with pre-compression.

The degree of delivery is in the arrangement according to the invention determined by the volume of the pre-compression space. The dead volume occurring here is due to the lower Pressure of less importance because the back-expanding Damage volume is not as extensive. The working medium in the precompression room is almost completely in the Main compression space transferred and what occurs there Dead volume restores the energy introduced into it Support for the return movement of the piston and thus for the pre-compression.

Training in a series The pre-compression and main compression space enables easy Valve arrangement. Every compression space therefore needs the development of the invention specified in claim 3 only one valve device for the supply and a valve device for the removal of the working medium. These valve devices can also be very simple and reliable be designed. The construction effort thus significantly reduced and the structural embodiment this simplifies considerably.

The fact that the space on both sides of the piston as a working space Is used, there is the advantage that a spatial separation of the feed device from the discharge device, such as. an arrangement on axially opposite Sides of the piston according to that in claim 4 specified development of the invention, is made possible. The feed device can thus e.g. arranged in the compressor block be while the discharge device in the cylinder head is provided and the further routing as desired can be chosen. Thus, the heating of the supplied Working medium through that due to the printing process heated dissipated working medium can be avoided. A the main design problem of conventional compressors is eliminated with it and the design of the compressor simplified yourself essential.

An annular feed groove directed towards the work area according to the training specified in claim 5 the invention enables a uniform inflow of sucked in working medium in the precompression room.

If the piston according to the training specified in claim 6 of the invention designed as a circular disc becomes, this allows a simple and inexpensive Manufacture of the same. Furthermore, the moving masses and the size of the friction surfaces can be kept small.

Since the disc-shaped piston according to claim 7 is preferred with a large number of openings or through holes is formed, it is possible on overflow channels in the cylinder head. The working medium can by the openings in the piston from the pre-compression chamber directly in be transferred to the main compression room. The constructive This reduces the effort for the cylinder head essential. Furthermore, the openings reduce the weight of the piston, which increases the size of the moving mass is lower.

An even distribution of the openings on the piston according to the further development of the in claim 8 Invention enables a balanced pressure distribution the piston. The burden on storage is therefore not one-sided and wear on the treads remains low.

In that the piston according to claim 9 at its openings preferably has a valve device allows overflow of the working medium and thereby but at the same time the pre-compression space from the main compression space be separated. The working medium can only be in flow into the main compression space while the opposite direction is blocked. Thus, a Separation of the compression areas achieved and at the same time the possibility of direct transfer of the working medium used without a detour via channels in the cylinder head. In order to the design of the compressor is further simplified.

The formation of the liner as a deep-drawn part allows the piston to be guided cost-effectively and precisely.

It is also possible to use the liner to be formed in one piece with the valve plate. Thereby the assembly effort is reduced.

Another advantage is that according to the claim 10 specified development of the invention by a crank loop drive without much effort two opposing ones Pistons can be driven. So it is possible with a simple construction a double compression cylinder to create and significantly increase performance.

This design also has the advantage that with only a few other parts e.g. a 2-, 4- or 8-cylinder version of the compressor is made possible. The compressor can thus to corresponding performance requirements without major Effort to be adjusted.

The execution as a multi-cylinder arrangement continues for a more even course of the drive torque in relation to those due to the size and construction Expenses usually only one-cylinder conventional compressors.

Furthermore, the crank loop drive allows a low one Piston speed, which enables dry running becomes. Furthermore, only small masses are moved and it there are only slight fluctuations in tangential force, which is why the strength requirements for the structure reduce.

The simple structure with only a few components of the compressor according to the invention allows inexpensive and easy manufacture and assembly. Like the installation space comparison with conventional compressors can also achieved a compact design with small dimensions become. Furthermore, a flexible redesign, e.g. of the Inlet device, according to the conditions of the site possible without great design effort.

Fig. 1 eine Schnittdarstellung des erfindungsgemäßen Verdichters;

Fig. 2 eine Schnittdarstellung eines Verdichters mit einer vereinfachten Antriebsvorrichtung; und

Fig. 3 einen Bauraumvergleich mit einem herkömmlichen Kompressor.

The invention is explained below with reference to the description of exemplary embodiments with reference to the drawing. It shows:

Figure 1 is a sectional view of the compressor according to the invention.

Figure 2 is a sectional view of a compressor with a simplified drive device. and

Fig. 3 shows a space comparison with a conventional compressor.

1, a compressor 1 has a compressor block 2, a crank loop drive 3 and two cylinder heads 4 on.

The compressor block 2 has as a feed device for the working medium (namely air) an inlet pipe sleeve 5 and an inlet line system 6, and as a discharge device for the compressed or compressed working medium an outlet pipe sleeve 7 and an outlet pipe system 8; further an inner cavity 9 is provided.

The crank loop drive is in the inner cavity 9 of the compressor block 2 3 housed. This has one Crank loop frame 10 on which a backdrop 11 is formed is. A sliding block 12 is placed in the backdrop 11 guided. The sliding block 12 is eccentrically guided on a crankshaft crank pin 13 and thus transforms e.g. through the crankshaft of an internal combustion engine a rotary motion applied to a truck in a longitudinal movement of the crank loop frame 10 around.

Furthermore, two disc-shaped are on the crank loop frame 10 Piston 14 attached. These lie on one axis and face each other. As a drive, a crank loop is used, the two pistons 14 lead one linear float out.

In each of the cylinder heads 4 there is a working space 15 and an outlet duct 16 are formed. In the work room 15 is a liner 17 attached.

In operation, the piston moves air into the Workspace 15 sucked in. The air flows through the inlet pipe sleeve 5 and the inlet line system 6 via an annular Feed groove 6a through one on the compressor block 2 arranged valve plate 18 in the work space 15. On the Valve plate 18, valve lamellae are arranged such that they only one direction of flow into the working space 15 allow.

The piston 14 then reverses its direction of movement and moves onto the annular feed groove 6a of the inlet pipe system 6 to. The valve plate 18 attached there prevents the air from flowing back. This will be pre-compressed and flows through openings 19 in the piston 14 and a valve device arranged behind it 20 in the resulting on the other side of the piston Working space. The centers of the openings 19 are on the same radius around the center of the disc-shaped Piston 14 arranged and evenly distributed thereon.

The extent of the delivery quantity of the compressor 1 is determined by the amount of the in the 1st stage, the pre-compression stage, aspirated working medium determined. Because the working medium that is not so highly compressed at this stage Back expansion share from the dead spaces less. The order receives a much higher degree of delivery.

The flow over to the other side of the piston 14 Air is then reversed by the piston movement compressed and against an integral with the liner 17 formed valve plate 21 pressed. This is possible because the fins of the valve device 20 also open the piston 14 only one direction of flow in the main compression space allow in.

The valve plate 21 has such a bias on that they only at a certain, preset Pressure opens. When opening the valve plate 21, the compressed Air is finally expelled into the outlet duct 16 and flows through the discharge line system 8 of the compressor block 2 through the outlet pipe sleeve 7 as compressed air (Compressed air).

Since the fins of the valve plate 21 also have only one direction of flow allow the compressed to flow back Air into the working space 15 during the return stroke of the piston 14 avoided.

The in due to the component tolerances and thermal expansion existing dead spaces compressed air expands back out and supported during the return stroke of the piston 14 the return stroke and thus the pre-compression of the air on the other piston side.

Precompaction is then carried out again during the return stroke Air through openings 19 and valve device 20 of the piston 14 inserted into the work space.

Since the piston 14 performs a purely linear movement, can a piston shaft 22 in the compressor block 2 guided and opposite by means of a sealing device 23 the inner cavity 9 of the compressor block 2, which drives the crank loop 3 houses, be sealed. Consequently can be avoided that oil particles in the work space 15th reach and cause oil coking of the valve devices. This will provide facilities for cooling the compressor not required and the design effort is reduced significant.

Through a further sealing device 24, the circumferential side is arranged on the piston 14, the compression spaces sealed against each other on both sides of the piston 14.

Because this arrangement only has a relatively low piston speed requires a dry run is possible. Also therefore no cooling device is necessary and Construction is further simplified.

On the drive shaft of the compressor according to the invention can easily with a few other components a second Compressors of the same type connected, e.g. a 4-cylinder star arrangement are formed. From two to the Drive shaft connected 4-cylinder compressors can be used 8-cylinder compressors are trained and other possible combinations are always open. An individual Adaptation to the respective performance requirements thus possible without much effort.

The simple design of the compressor enables also an adaptation to individual circumstances without big design changes. Another arrangement e.g. the inlet or outlet device can be easily be performed.

The crank loop drive 3 also has coated Backdrops 11, the dry running of the backdrop stone 12 enable.

2 is a simplified embodiment of a Crank loop drive shown; are in this with the same reference numerals denote the same parts. In this embodiment, pistons 30 become immediate through an off-center on a crankshaft that only is indicated indicated, mounted crank pin 33 driven. In this embodiment, one on one serves Piston shaft 31 formed sliding surface 32 as a counter surface for the crank pin 33. A backdrop and a sliding block are not necessary here. The piston skirt 31 is in the area the sliding surface 32 formed such that a spring 34 can clamp the piston 30 against the crank pin 33. This also guarantees the piston return movement. The remaining parts, in particular the compression section and the cylinders correspond to those of the first embodiment, so that reference is made to this.

3 is the compact design of the invention Compressor in the installation space comparison with a conventional one Compressors of the same performance shown. From this comparison it is clear that the compressor according to the invention is essential takes up less space.

Regarding further, not described here in more detail Features, advantages and effects of the invention are made explicit referred to the drawing.

Claims (11)

1. Compressor (1) for compressing a working medium, in particular for producing compressed air, having at least one piston (14) which can be moved backwards and forwards in a working chamber (15) to compress the working medium, a drive device for moving the piston (14) backwards and forwards, and a supply device and a discharge device for the supply and discharge of the working medium, a crank guide drive (3) being provided as the drive device,
   characterised in that
   the piston (14) travels in a liner which is constructed as a deep-draw part integral with the valve plate (21).
2. Compressor according to claim 1, characterised in that the working chamber (15) is divided into a pre-compression chamber and a main compression chamber by the piston (14) moving backwards and forwards.
3. Compressor according to claim 2, characterised in that the pre-compression chamber and the main compression chamber each have only one valve device for the supply and discharge of the working medium.
4. Compressor according to one of claims 1 to 3, characterised in that the supply and discharge device - seen in the direction of movement of the piston (14) - are arranged on opposite sides of the piston (14) of the crank guide drive (3).
5. Compressor according to one of claims 1 to 4, characterised in that the supply device is constructed as an inlet line system (6) arranged in a compressor block (2), the inlet line system (6) being provided with an annular supply groove (6a) facing towards the working chamber.
6. Compressor according to one of claims 1 to 5, characterised in that the piston (14) is constructed as a circular disc.
7. Compressor according to one of claims 1 to 6, characterised in that a plurality of apertures (19) extending in the axial direction are formed in the piston (14).
8. Compressor according to claim 7, characterised in that the centres of the apertures (19) are located on the same radius and are uniformly distributed on the piston (14) about the centre of the piston (14).
9. Compressor according to claim 7 or 8, characterised in that the piston (14) is provided with a valve device (20) arranged at the apertures (19).
10. Compressor according to one of claims 1 to 9, characterised in that the crank guide drive (3) drives a double compression cylinder with two oppositely acting pistons (4).
11. Compressor according to one of claims 1 to 10, characterised in that the compressor is constructed in accordance with a modular assembly technique, for instance as a 2, 4 or 8 cylinder version.

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