DE2230476A1 - DRY-RUNNING MOTOR COMPRESSORS IN HERMETICALLY ENCLOSED DESIGN - Google Patents

Description

Dry-running motor compressor in hermetically sealed design Die The invention relates to a hermetically encapsulated machine designed as a plunger-piston machine Motor compressor with a common shaft for the drive motor and the compressor, its pistons and bearings for the oil-free compression of gases or dampers for dry running are designed.

In known motor compressors of this type are those for the drive required electric motor and the compressor in a tightly sealed to the outside Housing arranged together and connected to one another by a shaft. At this i £ R area of the compressor are especially designed as a crankshaft shaft Arranged connecting rods that serve to drive the pistons.

It is also known in such motor compressors, the piston 1 for Designed to run dry and the bearings acting on the crankshaft as lubricated for life, Form sealed rolling bearings, on the one hand to the conveying medium to be compressed to protect against contamination by lubricant leakage etc. and on the other hand that in the storage chambers during production in preferably only small quantities to preserve the lubricant introduced during the entire service life of the machine.

The solution to the problem of grease escaping from such sealing elements the engine bearings subjected to rotation and pendulum motion is a prerequisite for the flawless and maintenance-free that is required over long periods of time Operation Only in this way can the possibilities of premature destruction or unreasonable Reduction of the service life of such machines (excluded and the risk of The unsuitability of such compressors for an intended application can be eliminated.

The invention is inter alia. from the knowledge that sic the danger the grease leakage from the engine bearings on the fatigue fracture of the seal material, especially at the clamping points of the seal. This can be done ahead of time due to that which takes place even under constant operating conditions of a plunger compressor periodic pressure change in the crankcase, which is responsible for sealing the greased rolling bearings Serving elastic components continuously stressed.

The cause of this behavior was recognized as the fact that the Pressure change from the euro area, essentially only on the respective outer surface of the seals acts, while a largely constant medium pressure level on the inside prevails, which is not due to the rapid change in external pressure caused by the speed and number of cylinders follows. The resulting pressure difference alone puts stress on the sealing elements in the harmful sense described above, with those that become effective over time adverse consequences.

In addition, this harmful effect becomes even more significant reinforced that with rapid changes in the operating pressure in the crankcase a The elastic seals used in the bearings are overloaded can that result from the higher acting here additionally on the sealing elements Pressure difference results.

Furthermore, these problems are exacerbated when such Machines during production in the factory in accordance with the statutory safety regulations are checked for pressure resistance and gas tightness, which is always done on the colored product takes place as the last work step, i.e. in the case of encapsulated INotor compressors after welding the housing encapsulation and, in the case of semi-encapsulated versions, after sealing and screwing the housing cover. It is common practice during such tests to set the compressor to the prescribed level To inflate pressure position, he is entitled to the completion of the tightness control and the pressure after the test has been carried out quickly, e.g. by opening a quick-acting valve, to drain. The pressure builds up in the compressor housing, i.e. around the engine, comparatively much faster than within the sealed, fastened Storage chambers, which is why the sealing elements are tested when the pressure is relieved are additionally claimed and thereby particularly adversely affected.

The invention is now based on the object of a motor compressor of the type mentioned above, which is due to its oil-free compression of the pumped medium is suitable for almost all areas of application, to be designed so that it lasts for a long time Works maintenance-free and reliably for periods of time, especially for a long time Guaranteed service life of the sealing elements. The volumetric dimensions kept small with little other equipment effort and an economical one Manufacturing can be achieved.

According to the invention this object is achieved in that the rolling elements The storage room leading to the crankcase is closed by elastic seals is, and that this lubricant-filled storage space for pressure equalization through a duct system is connected to the crankcase space or engine compartment. To this Art is a rapid pressure equalization between the greased leading the rolling elements Storage room and the surrounding Crankcase space ensured, so that no harmful differential pressure layers or forces resulting therefrom with corresponding adverse effects can be exerted on the elastic sealing elements.

For a space-saving one that is particularly small and space-saving Motor compressors are, according to an advantageous feature of the invention, the rolling elements of the bearing arranged between the connecting rod and the crankshaft directly on the crankshaft on, wherein the channel system from arranged in the crankshaft radial bores and there is a longitudinal bore extending in the axial direction, which is located in the area between The outer surface and the axis of rotation are arranged in the crankshaft.

Furthermore, it is also possible that the connection between the Rolling body leading storage space and the surrounding crankcase space serving channel system not to be arranged in the crankshaft, but according to a further invention Embodiment the channel system from one introduced into the outer ring of the roller bearing Build up longitudinal and transverse drilling.

In this embodiment, if necessary, on the case of bearings The usual inner ring is dispensed with and thus also a particularly space-saving motor compressor be created.

The same advantages have another embodiment in which the channel system consists of a pipe that runs through the outer ring perpendicular to the crankshaft Bore and a bore in the connecting rod that runs parallel to the crankshaft consists.

However, whoever prefabricated bearings are used and those during construction work required by the compressor is to be kept to a minimum, the channel system can consist of a longitudinal and cross-hole can be built.

It is also possible when using complete bearings, the channel system from a hole perpendicular to the crankshaft through the inner ring and one to produce a bore arranged in the outer surface of the crankshaft.

Further advantageous details of the invention emerge from the following Description of the exemplary embodiments on the basis of the associated drawings explained. 1 shows a schematic sectional view of the motor compressor, Fig. 2 the channel system in the crankshaft with associated connecting rod, Fig. 3 the Detail A from FIG. 2 in enlarged form and FIGS. 4 to 7 further embodiments of the channel system, with the channel system in the outer bearing ring in FIG. 4, FIG. 5 the channel system in the outer bearing ring and the connecting rod, FIG. 6 the channel system in the inner bearing ring and FIG. 7 the channel system in the inner bearing ring and the crankshaft is located.

In Fig. 1, a housing is bseichnet 1, the interior of which is through a partition 2 in the usual way into a Furbel building space 3 and an engine compartment 4 is divided. This encasing the crankcase space 3 and the engine compartment 4 Housing 1 is hermetically sealed to the outside and made of gas-tight and pressure-resistant Material manufactured, whereby the joints are welded when using a steel encapsulation, or the required mounting openings in the case of a casing made of cast iron can be closed pressure-tight and gas-tight by means of appropriate covers.

An electronic motor 5 is installed in the engine compartment 4, with its rotor a crankshaft (or possibly an eccentric shaft) penetrating the crankcase space 3 6 is connected. This crankshaft 6 is used to drive a connecting rod 7, which is in turn connected to a piston 9 located in the cylinder 8. The example The motor compressor shown as a suction gas-cooled compressor is the one to be pumped Gas is supplied on the motor side and passed through the electric motor 5 in the usual manner. The piston 9 of the compressor, which is preferably designed as an alternating current compressor is through a suction valve 10 and a duct leading to the engine compartment 4 11 the pumped medium is supplied, which after its compression through a pressure working valve 12 is pushed out into a pressure chamber 13. To return the from compression Resulting leakage gas which flows off into the crankcase space 3 is a connecting channel 14 to the engine compartment 4- provided for the compressor designed as a plunger-piston machine In particular, the Eurbel housing space 3 filled with the pumped medium is subject to this considerable pressure fluctuations, which can be seen, for example, in the event of changes in the operation state of the machine.

These pressure fluctuations that occur act on the entire after outside hermetically sealed crankcase space 3 and lead in particular in it the elastic materials located, for example the bearing seals Consequences, especially if there are different pressures on the inside and outside act.

Such pressure differences on the elastic bearing seals are avoided in the embodiment according to FIG. 2, in which part of an engine of an encapsulated motor compressor is shown in section. In this embodiment is with 15 a crankshaft (or possibly eccentric shaft) designated, attack on the one or more connecting rods serving for power transmission. In These connecting rods - here - 16 and 17 are each designed in particular as a needle bearing Rolling bearings 18 and 19 pressed in, these rolling bearings 18 and 19 sealed and are designed as lifetime-lubricated bearings. Since in particular for the sake of the Space saving with these rolling bearings 18 and 19 no inner rings are provided, the associated rolling elements 20, 21 run directly on the correspondingly surface-treated Crankshaft 15. The bearing chambers 22, 23 serving to hold the lubricant are closed on both sides by elastic sealing elements 24, 25, 26 or 27, which, as especially FIG. 3 shows, each with its one end in the corresponding Outer rings of the roller bearings 18 and 19 are attached, and their other ends the Eurbel shaft 15 rest.

To avoid pressure differences on the elastic sealing elements 24 to 27, a channel system is arranged in the crankshaft 15, which is used for pressure equalization between the storage chambers. ! 22 or 23 and the crankcase space surrounding them 3 serves.

This channel system consists of an axially introduced into the crankshaft 15 Longitudinal bore 28 and further radial bores 29, 30 and 31, the longitudinal bore 28 through the radial bores 29 and 30 with the corresponding bearing chambers 22 and

23 are connected, and the radial bore 31 communicates therebetween the crankcase space 3 and the longitudinal bore 28 produces.

The channel system is advantageously within the crankshaft 15 arranged that the axial longitudinal bore 28 at least in the shaft axis or offset parallel to this in the direction of the pressure-relieved zone of the crankshaft 15 is.

Furthermore, it is useful to have the radial bores 29, 30 and 31 as well to be arranged in the pressure-relieved zone of the crankshaft 15.

The dimensioning of the radially ending in the direction of the pressure load zone Radial bores 29, 30 and 31 of the channel system in terms of diameter is carried out so that on the one hand, a reduction in the service life of the bearing is avoided, which is particularly which concerns the rolling elements rolling over the hole exit. On the other hand, the Dimensioning is carried out in such a way that the unavoidable gas throttling due to pressure loss in the channel bore is largely avoided and production of the same is still in can be done in an economically justifiable manner, as a rule it is therefore twofold be, the radial bores 29 and 30 immediately next to the bearing zone of the rolling elements to be arranged and not to dimension the bore diameter too small.

Favorable values are, for example, based on a channel factor from K aS 400, whereby the channel factor results from the following relationship: K = DxB where: E = channel factor D = outer circle diameter of the rolling bearing in mm B = bearing width in mm d = diameter of the radially ending bore of the pressure equalization channel in mm.

The dimensioning of the longitudinal bore 28 should be at least 1.5 times of the diameter d determined from the channel factor, with the upper limit value this is 2d.

The pressure equalization effect can also be advantageously thereby be improved that starting from the central bore 28, several radially per bearing ending holes are arranged. Such arrangements are called multi-channel systems designated.

For bearings with a very large enveloping circle diameter or a relatively large one Tagerkanmern 22, 23 is the application of the multi-channel system described from the outset alternatively in order to achieve the desired effect here as well.

In order to ensure the required, rapid pressure equalization, are To largely avoid throttle whirls in the sewer system.

As previously described, the channel diameter cannot be freely selected which is why the total length of the channel bores is kept to an achievable minimum is to be limited, and dead spaces of any kind through filling plugs 32 are to be avoided are.

In addition, the edges of the inlet and outlet openings of the channel system in a suitable manner to avoid constrictions of the pressure equalization to avoid resulting gas flow at these points.

Further exemplary embodiments according to the invention are shown in FIGS.

4 to 7. The channel system used for pressure equalization exists 4 from a radial bore 34 made in the outer ring 33, which is connected is with a also in this outer ring 33 introduced longitudinal bore 35, the with the Eurbel housing space 3 is in connection.

Next is e2. possible according to FIG. 5, one of the entire outer ring 36 to provide penetrating radial bore 37, which is completed to the channel system through a longitudinal bore 39 located in the connecting rod 38.

In these two last-mentioned exemplary embodiments, if necessary the bearing inner rings are also dispensed with, making it a particularly small one Machine made.

However, should be the amount of work involved in manufacturing the motor compressor can be limited to a minimum, the required rolling bearings can also be used directly be equipped with a channel system serving for gas equalization. It is there possible, the inner ring 40 of the roller bearing with a radial bore 41 and a corresponding one To provide longitudinal drilling 42 (Fig. 6).

As shown in FIG. 7, there is also the possibility of inserting into the inner ring 43 to introduce a radial bore 44 which is connected to one in the outer surface of the crankshaft 45 arranged longitudinal bore 46 cooperates.

Claims (11)

Claims Ü) Hermetically sealed motor compressor with a common shaft for the drive motor and the compressor, its piston and bearings for oil-free compression of gases or vapors are designed for dry running, characterized in that the storage space (22, 23) leading the rolling elements (20, 21) to the crankcase space (3) is closed by elastic seals (24 to 27), and that this with Lubricant-filled storage space (22, 23) for pressure equalization through a channel system (28, 29, 30; 34, 35; 37, 39; 41, 42) with the crankcase space (3) or engine space (4) is connected. 2. Motor compressor according to claim 1, characterized in that the Rolling bodies (20, 21) arranged between the connecting rod (16, 17) and the crankshaft (15) Bearing directly on the crankshaft (15), and the channel system from in the Crankshaft arranged radial bores (29, 30, 31) and one in the axial direction extending longitudinal bore (28). 3. Motor compressor according to claim 1 or 2, characterized in that that the radial bores connecting the storage spaces (22, 23) with the longitudinal bore (28) (29, 30) in the connecting rod (16, 17) overlapped area of the crankshaft (15), and the longitudinal bore (28) and the crankcase space (3) connecting Radial bore (31) outside of the Be overlapped by the connecting rod (16, 17) Reichs is arranged in the crankshaft (15). 4. Motor compressor according to claim 1, 2 or 3, characterized in that that the longitudinal bore (28) in the relieved area between the outer jacket and the axis of rotation is arranged in the crankshaft (15). 5. Motor compressor according to claim 1, 2 or 3, characterized in gekem1-characterized, that the ends of the radial bores (29, 30) opening into the storage space (22, 23) are funnel-shaped and outside the load-bearing zones of the rolling elements (20, 21) end. 6. Motor Veraichter according to claim 1, characterized in that the Channel system from a longitudinal (34) introduced into the outer ring (33) of the roller bearing - and transverse bore (35) (Fig. 4). 7. Motor compressor according to claim 1 or 6, characterized in that that the transverse bore (good) opens into the crankcase space (3). 8. Motor compressor according to claim 1, characterized in that the Channel system from a perpendicular to the crankshaft through the outer ring (36) Bore (37) and one in the connecting rod (38) running parallel to the crankshaft Bore (59) consists (Fig. 5). 9. Motor compressor according to claim 1, characterized in that the Channel system from a longitudinal (41) introduced into the inner ring (40) of the roller bearing - and huerbbohrung (42) consists (Fig. 6). 10. Motor compressor according to claim 1 or 9, characterized gekennzeichl net, that the transverse bore (42) opens into the crankcase space (3). 11. Motor compressor according to claim 1, characterized in that gdkennæeichnet that1 Channel system from a perpendicular to the crankshaft (45) through the inner ring (43) Radial bore (44) and one in the outer surface of the crankshaft (45)! There is longitudinal bore (46) (Fig. 7).