EP3516171A1

EP3516171A1 - Screw compressor for a utility vehicle

Info

Publication number: EP3516171A1
Application number: EP17769061.7A
Authority: EP
Inventors: Gilles Hebrard; Jean-Baptiste Marescot; Jörg MELLAR; Thomas Weinhold
Original assignee: Knorr Bremse Systeme fuer Nutzfahrzeuge GmbH
Current assignee: Knorr Bremse Systeme fuer Nutzfahrzeuge GmbH
Priority date: 2016-09-21
Filing date: 2017-09-19
Publication date: 2019-07-31
Also published as: JP2019532221A; KR20190045944A; WO2018054854A1; JP6844005B2; BR112019005083A2; CN109790750B; CN109790750A; US20190203718A1; DE102016011443A1; US11181110B2

Abstract

The invention relates to a screw compressor (10) for a utility vehicle, comprising a housing (20), the housing (20) being filled with oil (22), and comprising at least one pair of compressor screws (16, 18), which are mounted in the housing (20) and serve to compress air supplied to the screw compressor (10), wherein in the assembled state a heat exchanger (74) is directly placed onto and installed on the housing (20), by means of which heat exchanger the temperature of the oil (22) contained in the housing (20) can be controlled.

Description

DESCRIPTION

Screw compressor for a commercial vehicle The present invention relates to a screw compressor for a commercial vehicle.

Screw compressors for commercial vehicles are already known from the prior art. Such screw compressors are used to provide the necessary compressed air for, for example, the braking system of the commercial vehicle.

In this context, in particular oil-filled compressors, especially screw compressors are known in which the task is to regulate the oil temperature. This is usually accomplished by having an external oil cooler, the compressor filled with the oil and the

Oil circuit is connected via a thermostatic valve. The oil cooler is here

Heat exchanger having two separate circuits, wherein the first circuit for the hot liquid, so the compressor oil is provided and the second for the cooling liquid. As a coolant, for example, air,

Water mixtures can be used with an antifreeze or other oil.

This oil cooler must then be connected to the compressor oil circuit via pipes or hoses and the oil circuit must be secured against leakage.

This external volume must also be filled with oil, so that the total amount of oil is increased. This increases the system inertia. In addition, the oil cooler must be mechanically housed and secured, either by surrounding brackets or by a separate bracket, which requires additional means of improvement, but also space.

From US 4,780,061 a screw compressor with an integrated oil cooling is already known. Oes Further, DE 37 17493 A1 discloses a arranged in a compact housing screw compressor system having an oil cooler on the electric motor of the screw compressor.

It is the object of the present invention to develop a screw compressor for a commercial vehicle of the type mentioned in an advantageous manner, in particular to the effect that it is simpler and the thermal inertia of the overall system can be reduced.

This object is achieved by a screw compressor with the features of claim 1. Thereafter, it is provided that a

Screw compressor for a commercial vehicle is provided with a housing, wherein the housing is filled with oil, the screw compressor further at least a few compressor screws (also called compressor rotors), which are mounted in the housing and used for compression of the screw compressor fluid, in particular air, wherein in the assembled state of the screw compressor directly to the housing, a heat exchanger is mounted and mounted, by means of which the temperature of the oil contained in the housing is adjustable.

The invention is based on the basic idea that by the direct placement of the heat exchanger on the housing, the total volume required and death volume of oil can be reduced. In particular, the direct placement of the heat exchanger on the housing of the screw compressor requires no large communication paths from the screw compressor housing into the heat exchanger. Rather, the oil can be taken directly from the

Screw compressor are introduced into the heat exchanger inside. The required oil volume is thus kept relatively low. The thermal inertia of the system is reduced. In other words, thus the dead volume is reduced, or the volume that must be filled with oil around the lines between

Casing interior and heat exchanger with oil to infest and allow oil circulation. In addition, this significantly reduces the risk of leakage because the required lines outside the housing must be avoided or at least provided with a shorter length.

Compared to the previously known screw compressors, the oil is brought quickly to operating temperature, especially in the start-up phase, when the oil is controlled by the thermostat initially does not flow through the heat exchanger / cooler and thereby quickly reaches operating temperature.

Furthermore, it can be provided that the housing a ring approach to

Receiving the heat exchanger. By means of the annular shoulder it becomes possible to enable a simple and correct positioning of the heat exchanger on the housing. In addition, a simple and reliable sealing option in both the axial and radial directions can be easily realized via the annular shoulder.

In addition, it can be provided that two ring lugs are provided in the housing, which is used to attach the heat exchanger to the housing of the

Serve screw compressor. About the double ring approach the sealing effect can be improved because this example, a kind of labyrinth seal can be made possible. It can also be provided to use the intermediate space between the walls of the ring projections as a fluid line between the housing and the heat exchanger.

In particular, it can be provided that the ring projections are formed concentrically. This facilitates positioning of the heat exchanger on the housing.

In addition, a concentric arrangement of the ring lugs is also useful in terms of sealing effect, which is required to seal the mounted on the housing heat exchanger at the interface to the housing accordingly. Furthermore, it can be provided that the housing has a receptacle for a

Has screw for fixing the heat exchanger. Hereby, a simple attachment of the heat exchanger by means of a screw on the housing can be made possible. In particular, it is conceivable that the receptacle for the screw is received in the interior of the two ring attachments. As a result, centering of the heat exchanger via the two can be achieved with essentially a simple work step

Ring approaches as well as fixing by means of the screw, which is housed inside the two ring approaches accomplish.

It can be provided that the screw for fastening the heat exchanger is a hollow screw. About the hollow screw, it is possible to supply oil to the heat exchanger or due to the hollow screw oil from the heat exchanger in the housing of the screw compressor.

In particular, it can be provided that the hollow screw serves as a fluid channel for the guided to the heat exchanger oil or the guided back from the heat exchanger into the housing oil.

It is conceivable that the heat exchanger is designed air-cooled.

The heat exchanger can be designed to be water-cooled. For example, it can be provided that the cooling water is mixed with antifreeze, for example methylene glycol or the like.

Furthermore, a thermostat and a control and / or

Regulation means may be provided by means of which the oil temperature of the oil in the housing can be monitored and adjusted to a desired value. This makes it possible to use the heat exchanger only if this is necessary. This makes it possible, for example when starting the screw compressor to reach the operating temperature faster. Further details and advantages of the invention will now be based on a in the

Drawings illustrated embodiment will be explained in more detail.

Show it: Fig. 1 is a schematic sectional view through an inventive

Screw compressor;

Fig. 2 is a perspective view of a screw compressor;

FIG. 3 shows a further perspective view of a screw compressor according to FIG. 2; FIG. and

Fig. 4 is a schematic, perspective sectional view through the

Heat exchanger and a part of the housing of the screw compressor of FIG. 2.

Fig. 1 shows a schematic sectional view of a screw compressor 10 in the sense of an embodiment of the present invention.

The screw compressor 10 has a mounting flange 12 for mechanical attachment of the screw compressor 10 to an electric motor not shown here.

Shown, however, is the input shaft 14, via which the torque from the electric motor to one of the two screws 16 and 18, namely the screw 16 is transmitted.

The screw 18 meshes with the screw 16 and is driven by this.

The screw compressor 10 has a housing 20 in which the essential components of the screw compressor 10 are housed.

The housing 20 is filled with oil 22.

Air inlet side is on the housing 20 of the screw compressor 10 a

Inlet port 24 is provided. The inlet nozzle 24 is designed such that an air filter 26 is arranged on it. In addition, an air inlet 28 is provided radially on the air inlet pipe 24. In the area between inlet port 24 and the Steep, where the inlet port 24 attaches to the housing 20, a spring-loaded valve core 30 is provided, designed here as an axial seal. This valve insert 30 serves as a check valve.

Downstream of the valve core 30, an air supply channel 32 is provided, which supplies the air to the two screws 16, 18. On the output side of the two screws 16, 18, an air outlet pipe 34 is provided with a riser 36.

In the region of the end of the riser 36, a temperature sensor 38 is provided, by means of which the oil temperature can be monitored.

Furthermore, a holder 40 for an air de-oiling element 42 is provided in the air outlet area.

The holder 40 for the air de-oiling element has in the assembled state in the area facing the bottom (as shown in Fig. 1), the air de-oiling element 42.

Further provided in the interior of the air de-oiling element 42 is a corresponding filter screen or known filter and oil-separating devices 44, which are not specified in detail. In the central upper area, relative to the assembled and ready-to-use state (ie as shown in FIG. 1), the holder for the air de-oiling element 40 has a

Air outlet opening 46, leading to a check valve 48 and a

Minimum pressure valve 50 lead. The check valve 48 and the minimum pressure valve 50 may also be formed in a common, combined valve.

Following the check valve 48, the air outlet 51 is provided. The air outlet 51 is connected to correspondingly known compressed air consumers in the rule.

In order to return the oil 22 located and separated in the air de-oiling element 42 back into the housing 20, a riser 52 is provided which has the outlet of the holder 40 for the air de-oiling element 42 when passing into the housing 20 a filter and check valve 54.

Downstream of the filter and check valve 54, a nozzle 56 is provided in a housing bore. The oil return line 58 leads back approximately in the middle region of the screw 16 or the screw 18 in order to supply oil 22 again.

In the assembled state of the bottom portion of the housing 20, an oil drain plug 59 is provided. About the oil drain plug 59, a

corresponding oil drain opening are opened, via which the oil 22 can be drained.

In the lower region of the housing 20 and the projection 60 is present, to which the oil filter 62 is attached. Via an oil inlet channel 64, which is arranged in the housing 20, the oil 22 is first passed to a thermostatic valve 66.

Instead of the thermostatic valve 66, a control and / or

Regulation means may be provided by means of which the oil temperature of the oil 22 located in the housing 20 is monitored and set to a desired value.

Downstream of the thermostatic valve 66 is then the oil inlet of the oil filter 62, which leads via a central return line 68, the oil 22 back to the screw 18 or the screw 16, but also to the oil-lubricated bearing 70 of the shaft 14. In the region of the bearing 70, a nozzle 72 is provided, which is provided in the housing 20 in connection with the return line 68.

The cooler 74 is connected to the projection 60, as will be explained in more detail below in FIGS. 2 to 4. In the upper region of the housing 20 (relative to the mounted state) there is a safety valve 76, via which an excessive pressure in the housing 20 can be reduced.

Before the minimum pressure valve 50 is a bypass line 78, which leads to a Entiastungsventii 80. About this relief valve 80 by means of a

Connection with the air supply 32 is controlled, air can be returned to the region of the air inlet 28. In this area, a vent valve not shown in detail and also a nozzle (diameter reduction of the feeding line) may be provided.

In addition, approximately at the level of the conduit 34 in the outer wall of the housing 20, an oil level sensor 82 may be provided. This oil level sensor 82 may be, for example, an optical sensor and arranged and set up so that it can be detected by the sensor signal, whether the oil level is above the oil level sensor 82 in operation or if the oil level sensor 82 is exposed and thereby the oil level has fallen accordingly. In connection with this monitoring, an alarm unit can also be provided which outputs or forwards an appropriate error message or warning message to the user of the system.

The function of the screw compressor 10 shown in FIG. 1 is as follows:

Air is supplied via the air inlet 28 and passes through the check valve 30 to the screws 16, 18, where the air is compressed. The compressed air-oil mixture, which rises above the riser 36 by a factor of between 5 to 16 times compression after the screws 16 and 18 through the outlet conduit 34, is blown directly onto the temperature sensor 38. The air, which still partially carries oil particles, is then guided via the holder 40 into the air de-oiling element 42 and, provided the corresponding minimum pressure is reached, enters the air outlet line 51. The oil 22 located in the housing 20 is conveyed via the oil filter 62 and, if necessary, kept at operating temperature via the heat exchanger 74.

If no cooling is necessary, the heat exchanger 74 is not used and is not switched on.

The corresponding flushing takes place via the thermostatic valve 68. After the purification in the oil filter 64, oil is supplied via the line 68 to the screw 18 or the screw 16, but also to the bearing 72. The screw 16 or the screw 18 is supplied via the return line 52, 58 with oil 22, here is the purification of the oil 22 in the air de-oiling 42nd

Above the electric motor not shown in detail, which transmits its torque via the worlds 14 on the screw 16, which in turn meshes with the shaft 18, the screws 16 and 18 of the screw compressor 10 are driven.

About the relief valve 80 is not shown in detail ensures that in the supply line 32 is not the high pressure prevailing in the operating state, for example, the output side of the screws 16, 18, can be locked, but that in particular at the start of the compressor in the supply line 32 always a low inlet pressure, in particular atmospheric pressure exists. Otherwise, with a start-up of the compressor, a very high pressure would initially arise on the output side of the screws 16 and 18, which would overload the drive motor.

In Fig. 2, the heat exchanger 74 is shown in a perspective view, which is placed directly on the housing 20. In the assembled state, therefore, the heat exchanger 74 is placed and mounted directly on the housing 20, wherein by means of the heat exchanger 74, the temperature of the oil contained in the housing 20 22 is regulated. As further shown in Fig. 3, a double concentric radial extension 60 is provided with an outer ring 60a and an inner ring 60b for attachment of the heat exchanger 74.

In the interior of the radial shoulder 60 b, a receptacle 90 is provided, which is for

Screwing a hollow screw 92 is used.

The hollow screw 92 serves on the one hand for fixing the oil cooler 74,

on the other hand, but also, as shown in Figure 4, for returning the guided and cooled by the oil cooler 74 oil 22 back into the housing 20 through the hollow screw inner channel 92 a. The area 98 between the concentric

Ring tabs 60a and 60b are used to supply oil 22 to the oil cooler 74.

The oil cooler 74 is designed as a water-cooled (in particular water-cooled with the addition of antifreeze). In another embodiment, an air-cooled heat exchanger may also be used.

The supply of the coolant takes place via the connections 94, 96 (see FIGS. 2 and 4).

As shown in Figure 4, the heat exchanger structure is formed here lamellar or here as a known and proven multi-plate structure.

LIST OF REFERENCE NUMBERS

10 screw compressor

12 mounting flange

14 input shaft

16 screws

18 screws

20 housing

22 oil

24 inlet ports

26 air filters

28 air intake

30 valve insert

32 air supply duct

34 air outlet pipe

36 riser

38 temperature sensor

40 holder for an air de-oiling element

42 air deoiling element

44 filter screen or known filter or Ölabscheidevorrichtungen

46 air outlet opening

48 check valve

50 minimum pressure valve

51 air outlet

52 riser

54 Filter and check valve

56 nozzle

58 Oil return line

59 Oil drain plug

60 approach

60a outer ring

60b inner ring

62 oil filter 64 oil inlet channel

66 thermostatic valve

68 return line

70 bearings

72 nozzle

74 coolers, heat exchangers

76 safety valve

78 bypass line

80 relief valve

82 oil level sensor

90 recording

92 Banjo bolt

92a hollow internal channel

94 connection

96 connection

98 area

Claims

A screw compressor (10) for a utility vehicle having a housing (20), said housing (20) being filled with oil (22) having at least one pair

Compressor screws (16, 18) which are mounted in the housing (20) and the

Compressing the air supplied by the screw compressor (10), wherein in the mounted state directly on the housing (20) a heat exchanger (74) is mounted and mounted, by means of which the temperature of the oil contained in the housing (20) (22) is adjustable.

2. screw compressor (10) according to claim 1,

characterized by »

for fixing the heat exchanger (74) a ring projection (60) on the housing (20) is provided.

3. screw compressor (10) according to claim 2,

characterized in that

two ring lugs (60a, 60b) are provided on the housing (20).

4. screw compressor (10) according to claim 3,

characterized in that

the ring lugs (60a, 60b) are arranged concentrically with each other.

5. Screw compressor (10) according to one of the preceding claims, characterized in that

the housing a receptacle for a screw (92) for fixing the

Heat exchanger (74).

6. Screw compressor (10) according to claim 5 and one of claims 3 or 4, characterized in that

the receptacle (90) for the screw (92) is received in the interior of the two annular projections (60a, 60b).

7. screw compressor (10) according to any one of claims 5 or 6,

characterized in that

the screw (92) is a banjo bolt.

8. screw compressor (10) according to claim 7,

characterized in that

the hollow screw (92) serves as a fluid channel for the oil (22) guided to the heat exchanger (74) or the oil (22) guided back into the housing (20) by the heat exchanger (74).

9. Screw compressor (10) according to one of the preceding claims, characterized in that

the heat exchanger (74) is water-cooled, in particular cooled by a water-antifreeze mixture.

10. screw compressor (10) according to any one of claims 1 to 8,

characterized in that

the heat exchanger (74) is air-cooled,

11. screw compressor (10) according to one of the preceding claims, characterized in that

a thermostat (66) and a control and / or regulating device

is provided, by means of which the oil temperature of the housing (20) located in the oil (22) is monitored and adjustable to a desired value.