JP2019536942A - Screw compressor system for commercial vehicles - Google Patents

Abstract

The invention relates to a screw compressor system (100) for commercial vehicles, comprising at least one screw compressor (10), at least one screw compressor drive, and at least one open-loop control unit and / or closed-loop control unit. (110), the open-loop control unit and / or the closed-loop control unit (110) is connected to the screw compressor drive, and the open-loop control unit and / or the closed-loop control unit (110) A commercial vehicle configured to monitor a ratio between a stop time and an operation time of a screw compressor driving device when the compressor (10) is operated, and to perform open-loop control and / or closed-loop control of the ratio within a predetermined range. Screw compressor system for Beam on (100).

Description

  The invention relates to a commercial vehicle having at least one screw compressor and at least one open-loop and / or closed-loop control unit for driving open-loop and / or closed-loop control of the screw compressor. Screw compressor system for a vehicle.

  Prior art screw compressors for commercial vehicles are already known. Such types of screw compressors are used, for example, to prepare the required compressed air for brake systems in commercial vehicles.

  In this connection, in particular, compressors filled with oil, in particular screw compressors, are also known, in which the control of the oil temperature is a problem. The control of the oil temperature is usually carried out by providing an oil-filled compressor and an external oil cooler connected to the oil circulation path via a temperature control valve. In this case, the oil cooler is a heat exchanger having two circulation paths separated from each other, and includes a first circulation path for a high-temperature fluid, that is, a compressor oil, and a second circulation path for a cooling fluid. Is provided. As the cooling fluid, for example, air, mixed water containing an antifreezing agent, or other oils can be used.

  The oil cooler must be connected to the compressor oil circuit via a line or a hose, and the oil circuit must be protected against leakage.

  Furthermore, since this external volume must be filled with oil, the total amount of oil is also increased. This increases the system inertia. Furthermore, the oil cooler must be mechanically stowed and mounted by means of a surrounding support or a separate support, which requires additional mounting means and thus also space for construction. I do.

  US Pat. No. 4,780,061 (US Pat. No. 4,780,061) discloses a screw compressor with an integrated oil cooling.

  Furthermore, DE 37 17 493 A1 discloses a screw compressor device arranged in a compact casing, the screw compressor device being of the screw compressor type. It has an oil cooler located on the electric motor.

  A screw compressor of the type mentioned at the outset is already known, for example, from DE 10 2004 060 417 A1 (DE 10 2004 060 417 B4).

  It is an object of the present invention to improve a screw compressor system of the type described at the outset, in particular to make it possible to configure the drive open-loop control and / or the drive-closed-loop control of a screw compressor simply and reliably.

  This object is achieved according to the invention by a screw compressor system having the features of claim 1. According to this, a screw compressor system for a commercial vehicle comprises at least one screw compressor, at least one screw compressor drive, and at least one open loop control unit and / or closed loop control unit. The open-loop control unit and / or the closed-loop control unit is connected to the screw compressor drive, and the open-loop control unit and / or the closed-loop control unit controls the stop time and the operation time of the screw compressor drive during the operation of the screw compressor. A screw compressor system for a commercial vehicle is provided that is configured to monitor the ratio of the vehicle and open-loop and / or closed-loop the ratio within a predetermined range.

  The idea underlying the present invention is that the temperature of the screw compressor is substantially defined by the ratio of the stop time and the operation time. According to the configuration of the screw compressor, it is sufficient that the screw compressor can function within an extremely narrow operating temperature range by controlling the ratio between the stop time and the operation time within a predetermined range. Since heat is generated by the screw meshing with each other, the oil flowing through the screw compressor, and the compressed air, by simultaneously selecting the ratio of the stop time and the operation time of the screw compressor driving device, Open-loop and / or closed-loop control of the heat of the screw compressor can be adjusted, ie adjusted.

  For example, the open loop control unit and / or the closed loop control unit may be a component of a screw compressor system, ie a screw compressor or a screw compressor drive. This forms a compact structure and does not need to involve external components.

  Basically, it is also conceivable that the open-loop control unit and / or the closed-loop control unit are components of a commercial vehicle air treatment system. In this case, there is already a corresponding control device which can be easily used together.

  It is also conceivable that the open-loop control unit and / or the closed-loop control unit are components of a commercial vehicle engine control or vehicle control. Also in this case, existing components of the commercial vehicle can be used.

  In principle, however, it is also conceivable for the open-loop control unit and / or the closed-loop control unit to be formed as a separate open-loop control unit and / or a closed-loop control unit. This allows, for example, simple assembly and simple replacement or simple upgrade.

  Furthermore, it is conceivable that said range is selected such that the ratio of the downtime to the operating time is about 20-50%, in particular more than 30%, of the operating time. Such a ratio of downtime to operating time, including an operating time of about 20-40%, in particular more than 30%, has been found to be relatively good in order to be able to keep the operating temperature substantially constant. Was. Furthermore, by ensuring a down time to operation time ratio, including an operation time of more than 30%, an operating temperature high enough to ensure that moisture formation or condensation inside the screw compressor is also avoided is maintained. The advantage also arises.

  Further, the open-loop control unit and / or the closed-loop control unit may influence the rotation speed of the screw compressor drive so that the ratio between the stop time and the operation time of the screw compressor drive is maintained in a predetermined range. It is possible that it is configured. Substantially in this case, a predetermined amount of compressed air should be provided over the entire operating period of the screw compressor, and by defining or limiting or increasing the rotational speed of the screw compressor, Starting from the fact that, while producing a constant compressed air, the ratio between the stop time and the operating time of the screw compressor drive can be influenced and thus this ratio can be maintained within a predetermined range. I have.

  In particular, it is conceivable for the open-loop control unit and / or the closed-loop control unit to be designed such that the rotational speed of the screw compressor drive is always maintained above the minimum rotational speed. Such means of keeping the rotational speed above the minimum rotational speed means that loss of power is limited only above a predetermined minimum rotational speed, and the screw compressor drive is almost impossible to generate a predetermined amount of compressed air. Based on the basic idea that energy is not required. In other words, this can improve the efficiency of the screw compressor drive as a whole. Therefore, for example, if the rotational speed is less than the minimum rotational speed of about 1500 to 2500 revolutions per minute, the loss output may increase significantly.

  Further details and advantages of the invention are explained in more detail with reference to the illustrated embodiment.

1 is a schematic sectional view of a screw compressor according to the present invention. FIG. 1 schematically shows a screw compressor system according to the invention.

  FIG. 1 is a schematic sectional view of a screw compressor 10 according to an embodiment of the present invention.

  The screw compressor 10 has a mounting flange 12 for mechanically mounting the screw compressor 10 to an electric motor (not shown).

  However, an input shaft 14 is shown, via which torque is transmitted from the electric motor to one of the screws 16 and 18, namely to the screw 16.

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

  The screw compressor 10 has a casing 20 in which the main components of the screw compressor 10 are housed.

  The casing 20 is filled with oil 22.

  An inlet pipe piece 24 is provided on the air inlet side of the casing 20 of the screw compressor 10. In this case, the inlet pipe piece 24 is formed such that the air filter 26 is disposed on the inlet pipe piece. Furthermore, the air inlet tube piece 24 is provided with an air inlet 28 in the radial direction.

  A spring-loaded valve insert 30 is provided in the region between the inlet piece 24 and the point where the inlet piece 24 is attached to the casing 20, in this case configured as an axial seal. Have been.

  Such a valve insert 30 functions as a check valve.

  An air supply passage 32 for supplying air to both screws 16 and 18 is provided downstream of the valve insert 30.

  An air outlet pipe 34 having a rising pipe 36 is provided on the outlet side of both screws 16, 18.

  A temperature sensor 38 is provided in the region of the end of the riser pipe 36, and the temperature sensor can monitor the oil temperature.

  Furthermore, a holder 40 for an air / oil separation element 42 is provided in the air outlet area.

  The holder 40 for the air / oil separating element has an air / oil separating element 42 in the area of the bottom side in the assembled state (as shown in FIG. 1).

  In addition, a corresponding filter screen or a known filtration and oil separation device 44 is provided inside the air / oil separation element 42, but will not be described in more detail.

  The holder 40 for the air / oil separating element has an air outlet opening 46 in the upper central region with respect to the assembled state and ready for operation (ie as shown in FIG. 1). Communicates with a check valve 48 and a minimum pressure valve 50. The check valve 48 and the minimum pressure valve 50 may be formed as one combined common valve.

  Subsequent to the check valve 48, an air outlet 51 is provided.

  The air outlet 51 is usually connected to a correspondingly known compressed air consumer.

  In order to guide the separated oil 22 present in the air / oil separating element 42 back into the casing 20, a rising line 52 is provided, which rise line of the air / oil separating element 42 is provided. Starting from the holder 40 for the transfer and into the casing 20, a filter and check valve 54 is provided.

  Downstream of the filtration and check valve 54, a nozzle 56 is provided in the casing bore. The oil return guide line 58 is returned to a substantially middle area of the screw 16 or the screw 18 to supply the oil 22 again to the screw.

  An oil discharge screw 59 is provided in a bottom area of the casing 20 in the assembled state. Via an oil discharge screw 59 a corresponding oil discharge opening is opened, through which the oil 22 can be discharged.

  In the lower region of the casing 20, an attachment portion 60 to which the oil filter 62 is attached is also provided. The oil 22 is first guided to the temperature control valve 66 via an oil filter inlet passage 64 arranged in the casing 20.

  Instead of the temperature regulating valve 66, an open-loop control and / or a closed-loop control which can monitor the oil temperature of the oil 22 in the casing 20 and can adjust it to a target value may be provided. .

  Downstream of the temperature control valve 66 is then the oil inlet of an oil filter 62, which returns the oil 22 to the screw 18 or to the screw 16 via the central return guide line 68. It is guided and returned to the oil-lubricated bearing 70 of the shaft 14. A nozzle 72 is also provided in the region of the bearing 70, which nozzle is provided in the housing 20 in communication with the return guide line 68.

  The cooler 74 is connected to the attachment part 60.

  In the upper region of the casing 20 (with respect to the assembled state) is located a safety valve 76 that can reduce the pressure in the casing 20 that is too high.

  A bypass line 78 leading to a pressure relief valve 80 is located just before the minimum pressure valve 50. Via this pressure relief valve 80, which is controlled by the connection with the air supply passage 32, air can be guided back into the area of the air inlet 28. This area may be provided with an air vent valve and a nozzle (reduced diameter portion of the supply line) not shown.

  Further, an oil level sensor 82 can be provided on the outer wall of the casing 20 substantially at the level of the conduit 34. The oil level sensor 82 may be, for example, an optical sensor, and the sensor signal indicates whether the oil level is above the oil level sensor 82 during operation or the oil level sensor 82 is exposed, It is configured and adjusted so that it can be detected whether the surface is correspondingly lowered.

  In connection with such monitoring, it is also possible to provide an alarm unit which issues or transmits a corresponding error notification or warning to the user of the system.

The functions of the screw compressor 10 shown in FIG. 1 are as follows:
Air is supplied via an air inlet 28 and reaches the screws 16, 18 via a check valve 30, where the air is compressed. After exiting the screws 16, 18, the air-oil mixture, which has been compressed by a factor of 5 to 16, rises through the outlet pipe 34 via the rising pipe 36 and is directly blown onto the temperature sensor 38.

  The air, which still contains oil particles, is then guided via the holder 40 to the air / oil separation element 42 and, when a corresponding minimum pressure is reached, to the air outlet line 51.

  The oil 22 present in the casing 20 is maintained at the operating temperature via an oil filter 62 and possibly via a heat exchanger 74.

  If cooling is not required, heat exchanger 74 is not used and is not turned on.

  The corresponding switch-on takes place via a temperature control valve 66. After purification in the oil filter 62, the oil is supplied to the screw 18 or the screw 16 via the pipe line 68, but also to the bearing 70. The screw 16 or the screw 18 is supplied with oil 22 via return guide lines 52, 58, in which case the purification of the oil 22 takes place in the air / oil separation element 42.

  The torque of an electric motor (not shown) is transmitted to a screw 16 via a shaft 14, and the screw 16 meshes with the screw 18, and the screws 16, 18 of the screw compressor 10 are driven via the electric motor. .

  Due to the pressure relief valve 80, which is not shown in detail, the high pressure which is formed, for example, on the outlet side of the screws 16, 18 in the ready state for operation is not confined in the region of the supply line 32, in particular when starting the compressor. In the region of the supply line 32, it is ensured that a low inlet pressure is always present, in particular atmospheric pressure. Otherwise, the starting of the compressor may initially cause a very high pressure at the outlet of the screws 16, 18 to overload the drive motor.

  FIG. 2 schematically shows a screw compressor system 100 according to the invention with the screw compressor 10 shown in FIG. 1 and the open and closed loop control unit 110.

  The open-loop control unit and the closed-loop control unit 110 are in this case formed as components of the screw compressor system 100.

  Basically, however, the open-loop control unit and the closed-loop control unit 110 may be a component of a commercial vehicle air treatment system, a component of a commercial vehicle engine control or vehicle control, or a separate open-loop control unit and closed-loop control unit. It can be assumed that it is formed as a control unit 110.

  In this case, the open-loop control unit and the closed-loop control unit 110 monitor the ratio between the stop time and the operation time of the screw compressor driving device for driving the screws 16 and 18 when the screw compressor 10 is operated, and determine this ratio by a predetermined value. It is configured to perform open loop control or closed loop control so as to fall within the range.

  In this case, the range is selected such that the ratio of the stop time to the operation time exceeds 30% of the operation time. In particular, in this case, a range in which the operating time is 30 to 50% is selected, so that the stopping time is 50 to 70% and the operating time is about 30 to 50%.

  If the operating time is about 30%, the downtime is about 70%.

  The open-loop control unit and the closed-loop control unit 110 are further configured to simultaneously influence the rotational speed of the screw compressor drive, so that the ratio of the stop time to the operation time can be kept correspondingly constant. I have.

  In this case, the desired amount of compressed air is provided by the screw compressor 10 over the entire operating period by decreasing or increasing the rotation speed of the screw compressor driving device, in which case the ratio between the stop time and the operation time is maintained. It is important that

  In order to work economically and energy-efficiently, in this case, the rotational speed is always maintained above the minimum rotational speed by the open-loop control unit and the closed-loop control unit 110.

This is based on the recognition that below the minimum speed, the proportional energy absorption of the screw compressor drive (ie the amount of energy required to compress one cubic meter (m ³ ) of air) increases significantly. Therefore, in other words, an excessively high loss output or an excessively high loss is avoided.

  Thus, by keeping the ratio of the stop time to the operation time constant, the screw compressor 10 as a whole can be kept relatively constant at the predetermined operation temperature over the entire operation time.

  Maintaining the compressor at a predetermined operating temperature over the entire operating period ensures that condensation does not occur in the casing 20 of the screw compressor 10.

  By maintaining the screw compressor 10 at and at a constant operating temperature, condensation in the casing 20 is reliably avoided.

DESCRIPTION OF SYMBOLS 10 Screw compressor 12 Mounting flange 14 Input shaft 16 Screw 18 Screw 20 Casing 22 Oil 24 Inlet pipe piece 26 Air filter 28 Air inlet 30 Valve insert 32 Air supply passage 34 Air outlet pipe 36 Up pipe 38 Temperature sensor 40 Air / oil separation Holder for element 42 Air / oil separation element 44 Filter screen or known filtration or oil separation device 46 Air outlet opening 48 Check valve 50 Minimum pressure valve 51 Air outlet 52 Up line 54 Filtration and check valve 56 Nozzle 58 Oil return guide line 59 Oil discharge screw 60 Attachment portion 60a Outer ring 60b Inner ring 62 Oil filter 64 Oil filter inlet passage 66 Temperature control valve 68 Return guide line 70 Bearing 72 Nose 76 safety valve 78 the bypass conduit 80 the relief valve 82 oil level sensor 100 screw compressor system 110 open-loop control unit and closed-loop control unit

Claims (8)

A screw compressor system (100) for a commercial vehicle, comprising at least one screw compressor (10), at least one screw compressor drive, at least one open loop control unit and / or a closed loop control unit (110). Has,
The open loop control unit and / or the closed loop control unit (110) is connected to the screw compressor drive,
The open-loop control unit and / or the closed-loop control unit (110) monitors a ratio between a stop time and an operation time of the screw compressor driving device when the screw compressor (10) is operated, and sets the ratio within a predetermined range. A screw compressor system (100) for a commercial vehicle configured to perform open loop control and / or closed loop control.   The screw compressor system (100) according to claim 1, wherein the open loop control unit and / or the closed loop control unit (110) is a component of the screw compressor system (100).   The screw compressor system (100) according to claim 1, wherein the open loop control unit and / or the closed loop control unit (110) is a component of an air treatment system of the commercial vehicle.   The screw compressor system (100) according to claim 1, wherein the open loop control unit and / or the closed loop control unit (110) is a component part of an engine control device or a vehicle control device of the commercial vehicle.   The screw compressor system (100) according to claim 1, wherein the open loop control unit and / or the closed loop control unit (110) is a separate open loop control unit and / or a closed loop control unit (110).   6. The range according to claim 1, wherein the ratio of downtime to operating time is selected such that the operating time is about 20-40%, in particular more than 30%. 7. The described screw compressor system (100).   The open-loop control unit and / or the closed-loop control unit (110) controls the rotation speed of the screw compressor driving device so that the ratio of the stop time and the operation time of the screw compressor driving device is maintained in the predetermined range. A screw compressor system (100) according to any one of the preceding claims, configured to affect the screw compressor.   The screw compressor system (7) according to claim 7, wherein the open-loop control unit and / or the closed-loop control unit (110) is configured such that the rotational speed of the screw compressor driving device is always maintained higher than a minimum rotational speed. 100).

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