Hydrodynamic machines, in particular hydrodynamic couplings

Abstract

The present invention relates to a hydraulic machine, in particular a hydraulic coupling. The hydraulic coupling comprises at least one first impeller as a pump wheel (20) and a second impeller as a turbine wheel (23) respectively assigned to the pump wheel (20). A working chamber (10) is formed by the pump wheel (20) and the turbine wheel (23). To transmit torque, the working chamber (10) is filled or can be filled with a working medium. At least one overflow channel (30), preferably a plurality of overflow channels (30), is provided in at least one of the impellers (20, 23) for discharging the working medium from the at least one working chamber (10). Preferably, the at least one overflow channel (30) passes through the impeller shell (21) of the corresponding impeller (20).

Description

TECHNICAL FIELD

[0001] The application can in principle be applied to any type of hydrodynamic machine and thus to a hydrodynamic torque converter, a hydrodynamic coupling or a hydrodynamic retarder. The application is, however, particularly advantageous in a hydrodynamic coupling having a so-called pump wheel as bladed primary wheel, usually driven by an input shaft, and having a so-called turbine as secondary wheel, which is driven by the pump wheel through a circulating flow in a working chamber. The turbine is usually carried by or kept in driving connection with a driven shaft. BACKGROUND

[0002] From DE 202 01 4 006 630 a hydrodynamic machine, in particular embodied as a hydrodynamic coupling, is known. The coupling has a bladed primary wheel and a bladed secondary wheel. The bladed wheels form an annular working chamber, which is filled or fillable with a working medium, for forming a hydrodynamic circulating flow of the working medium. Through the hydrodynamic circulating flow, torque or driving power can be transmitted from the primary wheel, also called pump wheel, to the secondary wheel, also called turbine, without losses and with damping of rotational vibrations. In a separation gap between the primary wheel and the secondary wheel a stationary throttle disc can be arranged, which projects into the working chamber. Through the extension and position of the throttle disc a torque limitation of the coupling can be achieved.

[0003] It is also known that the power data is pre-given or set by adjusting the distance of the primary wheel and the secondary wheel.

[0004] From DE 10 2016 215 739 A1 a coupling with controlled filling is known, in which the possible power transmission can be controlled by the amount of fluid in the working chamber of the coupling.

[0005] A hydrodynamic coupling for the transmission of force from a drive motor to a work machine is known from EP 1 127 231 B1. Preferably, work machines with a large mass or conveying a large mass are concerned, for example conveyor belts. With this hydrodynamic coupling it is achieved that the drive motor can be started only at low load. The work machine is moved only when the drive motor has reached its rated speed, or even after the drive motor has reached the rated speed. During the start-up process of the work machine, the hydrodynamic coupling automatically limits the torque transmitted by it to a certain value, so that the drive motor and the work machine are protected. The invention relates only to hydrodynamic couplings of the type which are operated with a constant amount of working fluid. That is to say, the interior space of the coupling is filled with a determined amount of working fluid at standstill, which remains constant during operation. In addition to the vaneed working chamber, the coupling has at least one retardation chamber which rotates with the primary wheel. In particular at standstill, a part of the working fluid accumulates in the retardation chamber. With this design, it is achieved that the vaneed working chamber is only partially filled with working fluid at the beginning of the start-up process and the filling level in the working chamber only gradually reaches the maximum possible value. It can be said that a coupling with an internal influence on the filling level of the working chamber is concerned. There are also hydrodynamic couplings with an external influence on the filling level of the working chamber, for example by means of a scoop tube. Couplings of this type have similar properties. However, the additional expenditure for the means for external influence is mostly only worthwhile in the case of a very high power density.

[0006] A hydrodynamic coupling is also known, for example from DE 10 2016 118 588, which has an enlarged surface at the impeller and is thereby able to transmit a greater drive power.

[0007] There are drive devices, for example for driving conveyor belts in the mining industry, in which a plurality of hydrodynamic couplings are arranged in parallel for power transmission. It happens that these hydrodynamic couplings have to be replaced. If only one of the two couplings arranged, for example, on the drive location like a driven drum has to be replaced, it would be advisable to install a new embodiment with a greater drive power on one side, but this is often abandoned because, for cost reasons, several, in particular two, hydrodynamic couplings arranged on the driven drum should not be replaced at the same time. On the other side, a coupling with the same drive power is usually used.

[0008] In the case of chain conveyors, a plurality of drives is usually provided, which drive the chain at spatially different locations. Due to the connection to the chain, the rotational speed at the driven side of the respective hydrodynamic coupling connected to the chain is predetermined. Thereby, different powers are transmitted in the case of different hydrodynamic couplings. In this way, for example, a hydrodynamic coupling with a large blade profile, also referred to as XL profile, can have a higher power than a hydrodynamic coupling with a smaller blade size at the same slip rate. If now both couplings are arranged together on a chain conveyor, an overload of the hydrodynamic coupling with the XL profile can result therefrom. SUMMARY

[0009] The task on which the present application is based is to provide a hydrodynamic coupling, the power and the performance capability of which can be reduced. Preferably, the performance capability can be reduced due to the construction of the hydrodynamic coupling.

[0010] According to the application, the task is solved by a hydrodynamic coupling having at least one first impeller as a pump wheel, wherein each pump wheel is assigned a second impeller as a turbine, wherein a working chamber is formed by the pump wheel and the turbine, and in order to transmit torque, the working chamber is filled or can be filled with a working medium, wherein at least one overflow channel is provided in at least one of the impellers, in order to discharge the working medium from at least one working chamber, wherein the at least one overflow channel has an inflow opening pointing towards the rotational axis, wherein the inflow opening is arranged in a region radially inside one half of the blades of the impeller.

[0011] The task is solved in that the drive power of the newly used hydrodynamic machine, in particular of the hydrodynamic coupling, is intentionally reduced. At a later point in time, the reduction can be cancelled again. Thereby, if one or more other hydrodynamic couplings are also converted into a coupling with increased drive power, the conversion into a hydrodynamic coupling with increased drive power can be completed.

[0012] The costs and the expense of such a conversion should be as low as possible. In particular, it is desirable to carry out the conversion without disassembling the coupling.

[0013] By means of the overflow channel, the power curve of the coupling can be changed, in particular the transmittable torque can be reduced. By means of the overflow channel, the working medium can be discharged from the working chamber. Thereby, the torque transmittable by the coupling can be reduced.

[0014] If, for example, a plurality of drive trains are provided on a chain conveyor and one of the hydrodynamic couplings can have transmitted a large torque to the chain at a high slip rate, there is a risk that exactly this drive train is overloaded. The reason for this is that the drive power of the coupling is caused by the torque and the drive train is connected to the other drive trains via the chain. In such a constellation, it is advantageous to reduce the drive power that can be transmitted or to coordinate the drive power that can be transmitted with the other drive trains. This coordination or reduction can be carried out, inter alia, by means of the hydrodynamic coupling.

[0015] It has proven advantageous if the overflow channel has an opening through the blade shell.

[0016] In a preferred embodiment, the overflow channel has a branch, wherein the branch preferably has an opening towards the scoop tube. Thereby, the working medium can be directly fed from the working chamber to the scoop tube.

[0017] In a preferred embodiment, it is provided that at least one overflow channel has an opening for accommodating working medium directed towards the axis of rotation. Thereby, the working medium can be discharged when it flows into the impeller. It has proven advantageous if the opening is arranged in a region of the impeller that is radially inner, preferably in a region that is radially inner one third.

[0018] In a preferred embodiment, it is provided that the overflow channel is integrated into the blade of the impeller. The arrangement of the overflow channel in the blade has a positive effect on the stability. The overflow channel can be supported, inter alia, by the blade. It is also conceivable to be arranged directly in front of the blade. A further advantage of the direct integration into the blade is that a relative movement of the blade and the overflow channel is prevented, which can also have a positive effect on the noise formation.

[0019] In a preferred embodiment, it is provided that the overflow channel is at least partially cast. Thereby, the manufacturing costs can be kept low.

[0020] In a preferred embodiment, it is provided that at least one overflow channel is arranged in the pump wheel or even integrated into the blade of the pump wheel. It has been shown that the arrangement of the overflow channel in the pump wheel is particularly efficient.

[0021] In another embodiment, it is provided that at least one overflow channel is integrated into an impeller configured as an outer rotor. Thereby, the openings of the impeller directed radially outwards are particularly easily accessible. It is possible, inter alia, that the overflow channel can be closed afterwards by means of a closable mounting opening that is usually provided in the housing. For this, it is then not necessary to disassemble the hydrodynamic coupling.

[0022] It is provided in a preferred embodiment that the length of the overflow channel exceeds 70% of the radius of the blades of the corresponding impeller. It has proven advantageous to use as overflow channel a small tube which can be inserted from the radially outer side, wherein the length of the small tube is adjustable and by the selection of the length the power data of the hydrodynamic coupling can be coordinated.

[0023] It is provided in a further embodiment that the overflow channel at its radially outer end, preferably in the region of the passage through the impeller housing, can be closed by a closure and thereby can be deactivated. For the closure a corresponding accommodation for the closure is configured in the housing of the corresponding impeller.

[0024] It is provided in a further embodiment that in the connecting flange of the impeller an accommodation for accommodating a closure for partially and / or completely closing the overflow channel is configured. Preferably, the radial opening of the overflow channel is arranged between axially arranged flange holes.

[0025] It is provided in a further embodiment that the overflow channel is provided in at least one impeller having an XL profile. Thereby the application possibilities of the hydrodynamic coupling are extended. In particular a joint application with other modules having different power curves is possible.

[0026] It has proven advantageous that in the case of a coupling having two pump wheels and two turbines only one of the impellers, preferably only one pump wheel, is equipped with an overflow channel. Thereby it becomes particularly simple to adjust the power data later by closing the overflow channel. Such an arrangement also has a favorable effect on the production costs.

[0027] Preferably, the overflow channel is used only in a hydrodynamic coupling with controlled filling. In the case of this coupling type the working medium which is discharged via the overflow channel can be delivered again by the already existing pump.

[0028] It has proven advantageous that there are at least four overflow channels and that one overflow channel is assigned to each four blades of at least one impeller. Preferably, the overflow channels are integrated into the corresponding blades.

[0029] The previously described hydrodynamic coupling is particularly suitable for use in chain conveyors.

[0030] The previously described hydrodynamic coupling can be operated particularly advantageously with water as working medium. BRIEF DESCRIPTION OF DRAWINGS

[0031] Further advantageous implementation forms of the application are explained below with reference to embodiments. The features mentioned can advantageously be realized not only in the combinations indicated, but also in other combinations or in isolation without, however, departing from the scope of the application. The drawings show in detail:

[0032] Figure 1 A 3D illustration of an impeller with an integrated overflow channel is shown;

[0033] Figure 2 The impeller is shown in 2D view;

[0034] Figure 3 A fragment of a fluid coupling with an overflow channel is shown;

[0035] Figure 4 A conveyor with a drive train is shown;

[0036] Figure 5 A hydrodynamic double coupling with a closed overflow channel is shown. DETAILED DESCRIPTION

[0037] These figures are described in more detail below.

[0038] First, based on Figure 4 The following describes a drive train 1 for driving a chain conveyor having a chain 7. The conveyor chain allows the transport of goods along a conveying direction 12. A drive train is provided to drive the chain, which drives the chain via a drive drum. To drive the chain 7, multiple drive trains (not shown) are distributed along the conveying path. These drive trains are connected via the chain. If different drive lines were introduced for the different drive trains, each drive train could become overloaded.

[0039] exist Figure 4 The drive train shown in FIG has a motor 2, a fluid coupling 3, and a transmission 4. The drive power of the motor is transmitted via the fluid coupling 3 and the transmission 4 to the shaft 5 of the drive drum 6. In the case of chain conveyors, the coupling of the drive train is more prominent because the chain star wheel may not slip as easily as the drive drum in a goods conveyor.

[0040] The fluid coupling 3 has a housing 8, wherein the housing 8 is equipped with a housing cover 9. Possible arrangements of the fluid coupling are Figure 5 The coupling 3 is shown in fragment form. It has a first and a second pump impeller 20. These two pump impellers 20 are connected to one another via a connecting element 18. These impellers are designed as external rotors. Each impeller is assigned a turbine. These turbines are designed as internal rotors, meaning that the connection between the two turbines 23 is arranged radially within the connection between the two impellers.

[0041] Each of these pump wheels 20 has a pump wheel housing 21. The pump wheel housing is connected with the drive shaft and is driven by the drive shaft 15. The two turbines 23 also each have a turbine housing and turbine blades 25 arranged in the turbine housing 24. The turbine blades are fixedly connected with the driven shaft 16. Through the working medium in the working chamber formed by the pump wheel 20 and the turbine 23, torque is transmitted from the pump wheel 20 to the turbine 23. The embodiment shown is a fillable fluid coupling which is filled with the working medium for torque transmission. For replacement, a scoop tube 14 is provided. Through the scoop tube 14, the working medium which has overflowed from the working chamber is diverted away.

[0042] The pump wheel facing the scoop tube is equipped with pump wheel blades 22 which have an overflow channel 30. The overflow channel 30 shown there comprises a small tube. If the small tube is not integrated into the blade, an adjustment or change of the power profile of the coupling can be carried out by shortening the inserted small tube. The radial length of the small tube is indicated and relates to the radial extension of the respective impeller to which the overflow channel is assigned. The axial direction is indicated with 27 and coincides with the rotational axis of the drive shaft 15 / driven shaft 16.

[0043] If the small tube is fixedly connected with the blade, such as shown in Figure 1 and 2 , this small tube cannot be shortened from the outside so simply. An adjustment can be carried out by reducing the extent of the inflow opening 41 of the overflow channel 30.

[0044] The overflow channel integrated in the blade has the advantage that the overflow channel 30 is supported by the blade 22. The overflow channel is configured at its radial end with a branch 37. This branch has an opening 39 which points in the axial direction to the scoop tube and a radial opening 38. Through the provision of a closure, the radial opening 38 and the axial opening 39 can be closed, as shown in Figure 5 . However, it is also possible to only close the radial opening 38, as shown in Figure 3 . In the embodiment shown in Figure 3 , a screw plug 34 is provided as closure 32. Through the opening of the lid 9 in the housing, the overflow channel 30 can also be easily closed in the pump wheel configured as an external rotor after the fact. Through the closure, the maximum working capacity of the fluid coupling 4 can be achieved.

[0045] In Figure 1In the diagram shown in the middle, the spill flow channel is integrated into the blades of the impeller. The flow direction of the working medium is drawn with arrows 26. If there is little working medium in the coupling, no working medium reaches the spill flow channel 30 yet. The full start-up torque is provided. As the filling increases, the openings 41 of the spill flow channel 30 are traversed and a part of the working medium is discharged, whereby the transferable power is reduced. If the spill flow channel is now limited by partial closures, for example by partial closures which can be fastened into the housing, the amount of working medium which flows out is changed and thereby the power data of the coupling are changed. A screw plug 34 for completely closing the spill flow channel can also be fastened in the housing. Thereby, the maximum working capacity of the hydrodynamic coupling can be provided.

[0046] Although the spill flow channel 30 is shown here in the pump wheel 20, a spill flow channel can also be provided in the turbine 23 for the power adjustment of the hydrodynamic coupling.

[0047] If a coupling with a large blade profile as known from EP 2 140 161 is to be used together with other couplings with a smaller power transfer, an overload of the coupling with the XL profile can be prevented by an initial power reduction. Therein, an adjustment can be made by closing some of the provided spill flow channels when the power characteristics of the other drive train change.

[0048] List of reference signs

[0049] 1 drive train

[0050] 2 drive; motor

[0051] 3 hydrodynamic coupling

[0052] 4 transmission

[0053] 5 shaft drive drum

[0054] 6 drive drum

[0055] 7 conveyor chain

[0056] 8 housing

[0057] 9 housing cover

[0058] 10 working chamber

[0059] 11 XL profile (EP 2 140 161)

[0060] 12 conveying direction 13

[0062] 14 spoon tube

[0063] 15 drive shaft

[0064] 16 driven shaft

[0065] 18 connecting element of the pump wheel 19

[0067] 20 pump wheel

[0068] 21 pump wheel housing

[0069] 22 pump wheel blade

[0070] 23 turbine

[0071] 24 turbine housing

[0072] 25 turbine blade

[0073] 26 flow direction of the working medium

[0074] 27 axial direction

[0075] 29 radial direction

[0076] 30 overflow channel

[0077] 32 closure of the overflow channel

[0078] 33 outer rotor (pump wheel)

[0079] 34 screw plug

[0080] 35 blade with integrated overflow channel

[0081] 36 recess of the inlet of the overflow channel

[0082] 37 branch

[0083] 38 radial opening of the overflow channel

[0084] 39 axial opening of the overflow channel

[0085] 41 inflow opening of the overflow channel

Claims

1. A fluid coupling (3) comprising at least one first impeller as a pump wheel (20), wherein: A second impeller as a turbine wheel (23) is assigned to each pump wheel (20), wherein a working chamber (10) is formed by the pump wheel (20) and the turbine wheel (23), and the working chamber (10) is filled or can be filled with a working medium for transmitting torque. It is characterized by: At least one overflow channel (30) is provided in at least one of the impellers (20, 23) for discharging a working medium from at least one working chamber (10), wherein the at least one overflow channel (30) has an inflow opening (41) pointing toward the axis of rotation, wherein the inflow opening (41) is arranged in the radially inner half of the blades (22) of the impeller (20).

2. The fluid coupling according to claim 1, It is characterized by: A plurality of overflow channels (30) are provided in at least one of the impellers for discharging a working medium from at least one working chamber (10).

3. The fluid coupling according to claim 1, It is characterized by: The at least one overflow channel (30) passes through the impeller shell of the corresponding impeller.

4. The fluid coupling according to claim 1, It is characterized by: The inflow opening (41) is arranged in the radially inner third region of the blades (22) of the impeller (20).

5. The fluid coupling according to any one of claims 1 to 4, It is characterized by: The overflow channel (30) is integrated into the blades (35) of the impeller (20).

6. The fluid coupling according to claim 5, It is characterized by: The overflow channel (30) opens into a recess (36) in the blade (22).

7. The fluid coupling according to any one of claims 1 to 4, It is characterized by: The overflow channel (30) is at least partially cast into the blades of the pump wheel (20) or turbine wheel (23).

8. The fluid coupling according to any one of claims 1 to 4, It is characterized by: The at least one overflow channel (30) is integrated into the pump wheel (20).

9. The fluid coupling according to any one of claims 1 to 4, It is characterized by: The at least one overflow channel (30) is integrated into an impeller designed as an external rotor (33).

10. The fluid coupling according to claim 5, It is characterized by: The length of the overflow channel (30) exceeds 70% of the radial length of the blade, wherein the overflow channel (30) is a small tube that can be inserted from the outside, wherein the length of the small tube is adjustable.

11. The fluid coupling according to any one of claims 1 to 4, It is characterized by: The overflow channel (30) can be closed at its radially outer end by a closure element (32) and can thereby be deactivated.

12. The fluid coupling according to claim 3, It is characterized by: The transfer channel (30) can be closed in the region through the impeller shell by a closure element and can thereby be deactivated.

13. The fluid coupling according to any one of claims 1 to 4, It is characterized by: A receptacle for receiving a closure element (32, 34) is formed in the connecting flange of the impeller, the closure element being used to partially and / or completely close the overflow channel (30).

14. The fluid coupling according to any one of claims 1 to 4, It is characterized by: The overflow channel (30) is arranged in at least one impeller having a large blade profile (11).

15. The fluid coupling according to any one of claims 1 to 4, It is characterized by: The fluid coupling has two pump wheels (20) and two turbine wheels, and the overflow channel (30) is provided in only one of the impellers (20).

16. The fluid coupling according to any one of claims 1 to 4, It is characterized by: There are at least four overflow channels (30) and at most one overflow channel (30) is associated with every four blades of at least one of the impellers.

17. Drive system, characterized in that The drive train (1) comprises at least one hydrodynamic coupling (3) according to any one of claims 1 to 16, which has at least one overflow channel (30).

18. The drive train according to claim 17, It is characterized by: The drive train is for a chain conveyor having a drive and a dynamic coupling.

19. Goods conveyor or chain conveyor having multiple drive trains, It is characterized by: At least one of the drive trains comprises a hydrodynamic coupling (3) according to any one of claims 1 to 16.

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