Patent Application
20200124153
The invention concerns a power transmission device, more specifically having the features of the preamble of claim 1.
Power transmission devices in drive trains for driving a working machine with variable rotation speed are known from the prior art in various designs. These are interposed between a drive machine, which can be operated with a constant rotation speed, and a working machine. For example, reference is made to Voith publication cr168de “Efficient control of pumps and compressors”; April 2013, and to WO2015071349 A1 and WO2012143123.
Such a power transmission device comprises at least one input which is or can be connected at least indirectly to the drive machine, an output which is or can be connected at least indirectly to the working machine, a hydrodynamic rotation speed/torque converter with at least one impeller, a turbine blade wheel and a guide wheel which form a working space that can be filled with operating medium, wherein at least one of the blade wheels comprises adjustable blades or adjustable blade segments, and a superposition gear mechanism. The superposition gear mechanism comprises at least one planetary gear mechanism with a ring gear, a sun wheel and a planet carrier with several planets, as elements of the planetary gear mechanism. The input of the power transmission device is connected at least indirectly, preferably directly, to the impeller of the hydrodynamic converter and to a first element of the planetary gear mechanism. The turbine wheel of the hydrodynamic converter is connected at least indirectly, preferably directly, to a second element of the planetary gear mechanism, and a third element of the planetary gear mechanism is at least indirectly connected to or forms the output. The power is transmitted by power division over a hydrodynamic branch and a mechanical power branch, wherein the power portions are combined in the planetary gear mechanism. An operating medium supply and/or conduction system is assigned at least to the converter, preferably to the power transmission device, and a device is provided for filling and/or emptying the converter. The converter is filled during operation.
A generic power transmission device in compact design, with the converter formed as a reverse torque converter and a planetary gear mechanism, is previously known from WO2012143123 and WO2015071349 A1. To control the transmission behavior of the converter, this is configured as an adjustable converter with adjustable blades on the guide wheel or impeller. With this measure, the transmission behavior can be controlled over a predefined rotation speed range. However, the rotation speed range which can be covered thereby is very small. If furthermore such a drive concept is used for driving working machines with high power demand, start-up takes place under very high load due to the inertia of the working machine. This requires very high necessary starting currents of the electrical drive machine, which result in great network fluctuations and require a corresponding design thereof.
The invention is therefore based on the object of refining a power transmission device for driving a working machine with variable rotation speed, and a method for its operation, so as to avoid the disadvantage of high necessary starting currents on use of electric drive machines, or high necessary start-up moments.
The solution according to the invention is characterized by the features of claim 1. Advantageous embodiments are described in the subclaims.
A power transmission device with an input for connection to a drive machine which can be operated at a constant rotation speed, and at least one output for connection to a working machine which can be driven at a variable rotation speed, comprises:
The power transmission device according to the invention is characterized in that the reverse torque converter can be emptied. Furthermore, a selectable control clutch is provided for transmitting the power in a first rotation speed range, with an emptied reverse torque converter, between the input and the output of the power transmission device, and a device for at least indirectly supporting and/or fixing the second element of the planetary gear mechanism, in particular the connection between the turbine wheel of the reverse torque converter and the second element of the planetary gear mechanism in this first rotation speed range. The reverse torque converter is active in a second rotation speed range.
According to the invention, to improve the start-up behavior and to avoid high run-up currents of the drive machine, a selectable control clutch is provided in the power transmission device and serves for power transmission at least over a partial range of the operating range outside the control range of the reverse torque converter. This takes place in a first rotation speed range, in particular during start-up of the drive machine, and performs the power transmission between the input and the output of the power transmission in this speed range. The control clutch allows gentle and stepless adjustment of the torque transmission during start-up of the drive machine, whereby a load-free run-up is possible. Thus rotation speeds at the output of the power transmission device can be set within a rotation speed range which cannot be achieved with the control range of the reverse torque converter or can only be achieved with significant modifications to this.
“Selectable” in the sense of the invention means that the control clutch has at least two operating states—activated and deactivated.
The term “control clutch” implies the capacity of the clutch to act as a torque converter, and set in targeted fashion the rotation speed at the clutch output and hence at the output of the power transmission device which is at least indirectly connected thereto. For this, the control clutch comprises at least two clutch parts which can be brought at least indirectly into active engagement with each other.
In order to achieve a unit with dimensions as compact as possible and with minimal number of components, preferably the reverse torque converter, the superposition gear mechanism and the selectable control clutch are arranged coaxially to each other. In a particularly advantageous refinement, the input, output and reverse torque converter, the superposition gear mechanism and selectable control clutch, are arranged coaxially to each other.
With regard to the arrangement of the control clutch, there is a multiplicity of possibilities. Preferably, in the basic configuration, the reverse torque converter and the superposition gear mechanism, viewed in the axial direction from the input to the output of the power transmission device, are arranged directly adjacent to each other, i.e. without any interposition of the control clutch. According to a first embodiment, the latter may be arranged on the input side, i.e. upstream of the basic configuration of reverse torque converter and superposition gear mechanism, in other words on the side of the reverse torque converter facing away from the superposition gear mechanism; or, according to a second particularly advantageous embodiment, downstream of the basic configuration of reverse torque converter and superposition gear mechanism, and hence on the side of the superposition gear mechanism facing away from the reverse torque converter.
In the first embodiment, the impeller of the reverse torque converter and the output part of the control clutch are directly connected together, in particular arranged on one shaft, wherein a direct drive device is assigned to the control clutch in order to bridge this and create the connection between the input and the impeller of the reverse torque converter. This first embodiment offers the advantage that on the output side, either a direct coupling can take place between the output and the superposition gear mechanism, or arbitrary further rotation speed/torque conversion devices may be arranged without restrictions between the superposition gear mechanism and the output.
In the second embodiment, the input part of the control clutch is connected to the third element of the planetary gear mechanism or superposition gear mechanism. A direct drive device is assigned to the control clutch in order to bridge this and create the connection between the third element of the superposition gear mechanism and the output. The particular advantage of this second embodiment is that the input part of the control clutch, because of its coupling to the output of the superposition gear mechanism, in particular the planetary gear mechanism, is already driven with a higher rotation speed, and the control clutch may therefore be dimensioned substantially smaller with regard to transferable moments, which results in lower costs as well as a saving in installation space.
In a refinement of the second embodiment, the output part of the control clutch is connected either directly or via a rotation speed/torque conversion device, in particular a spur gear train, to the output of the power transmission device. In this way, it is possible to introduce additional step-up or step-down ratios in the power transmission device. Furthermore, a standardized basic configuration of reverse torque converter and superposition gear mechanism may be used, which may then be adapted to the actual application requirements by means of the additional rotation speed/torque conversion device.
In both embodiments, in general the input and output may be arranged coaxially or eccentrically relative to each other.
With regard to the configuration of the direct drive device, there is a multiplicity of possibilities. Preferably, mechanical devices in the form of selectable clutches are used. According to a particularly advantageous embodiment, the direct drive device is also formed by the control clutch in a concentration of function. This is conceivable in particular in the case of mechanical control clutches as controllable multiplate clutches.
The direct drive device may however also be configured and arranged as a separate clutch device, as a bridging clutch.
In an advantageous embodiment with minimal wear, the control clutch is configured as a controllable hydrodynamic clutch, in particular a hydrodynamic clutch with fill control. Filling may be easily controlled in a targeted fashion, for example via valve devices in the supply to and/or discharge from the working space, or via so-called scoop tubes.
In order to be able to drive the third element of the planetary gear mechanism, a device is provided for supporting and/or fixing the second element of the planetary gear mechanism, in particular the connection between the turbine wheel of the reverse torque converter and the superposition gear mechanism. This device is preferably configured as a braking device, in particular a hydrodynamic retarder, wherein the rotor is directly connected to the turbine wheel of the reverse torque converter or to the connection between the turbine wheel and the second element of the planetary gear mechanism. The stator may be connected to either a component fixed relative to the housing, or to the first element of the planetary gear mechanism. Here, the embodiment as a hydrodynamic retarder has the advantage that the support force can be freely set.
In an alternative embodiment of the device, the latter is designed as a clutch device comprising at least two clutch parts which can be brought at least indirectly into active connection with each other. A first clutch part is connected directly to the turbine wheel of the reverse torque converter or to the connection between the turbine wheel and the second element of the planetary gear mechanism, and the second clutch part is connected to a component fixed relative to the housing, or to the first element of the planetary gear mechanism.
In order to provide a particularly compact power transmission device, the superposition gear mechanism comprises only a planetary gear mechanism. The first element of the planetary gear mechanism is formed by the carrier, the second element of the planetary gear mechanism is formed by the sun wheel, and the third element of the planetary gear mechanism is formed by the ring gear.
In order to freely control the transmission behavior, the reverse torque converter is configured as an adjustable converter comprising adjustable blades or adjustable blade segments on at least one of the blade wheels—impeller, turbine wheel and/or guide wheel.
The invention furthermore concerns a drive train with a drive machine which can be driven with a constant rotation speed, and with a power transmission device as claimed in any of claims 1 to 12 for driving a working machine with variable rotation speed. The rotation speed of the working machine can be freely set over a large rotation speed range.
The method according to the invention for operating a power transmission device as claimed in any of claims 1 to 12 is characterized by the following method steps:
The solution according to the invention is explained below with reference to figures. The drawings show the following in detail:
The power transmission devices 1 depicted in the following figures all comprise an input E, an output A, a reverse torque converter 2, a superposition gear mechanism 3, a control clutch 20 and a device 25 for supporting and/or fixing the second element of the planetary gear mechanism 4, in particular the connection between the reverse torque converter 2 and the superposition gear mechanism 3.
The power transmission device 1 is depicted as an example in a drive train 10 for driving a working machine 11, in particular with variable rotation speed, by means of a drive machine 9, in particular a drive machine with constant rotation speed. The power transmission device 1 is arranged in the force flow between the drive machine 9 and the working machine 11.
The power transmission device 1 comprises at least one input E which is connected at least indirectly to the drive machine 9, and an output A which is or can be connected at least indirectly to the working machine 11, a hydrodynamic rotation speed/torque converter configured as a reverse torque converter 2, and a superposition gear mechanism 3 comprising at least one planetary gear mechanism 4. The input E and output A are preferably configured as input and output shafts. It is also conceivable to configure these in the form of torque-transmitting function components. The phrase “is or can be connected at least indirectly” means connected either directly or via further intermediate components, which may include also devices for rotation speed/torque conversion, for example spur gear stages or further planetary gear stages.
The superposition gear mechanism 3 comprises at least one—in the particularly advantageous and compact embodiment depicted, precisely one—planetary gear mechanism 4 with at least a ring gear 5, a sun wheel 6 and a carrier 8 carrying the planet wheels 7, as elements of the planetary gear mechanism 4. The planet wheels 7 are mounted rotatably on the carrier 8.
The hydrodynamic reverse torque converter 2 comprises at least one impeller P, a turbine wheel T and a guide wheel L. The input E is connected at least indirectly, preferably directly, to the impeller P and to a first element of the planetary gear mechanism 4; the turbine wheel T is connected at least indirectly, preferably directly, to a second element of the planetary gear mechanism 4; and the output A is connected at least indirectly, preferably directly, to a third element of the planetary gear mechanism 4.
The connection to the planetary gear mechanism 4 here takes place such that the impeller P of the hydrodynamic reverse torque converter 2 is coupled to the carrier 8 of the planetary gear mechanism 4 and to the input E, while the turbine wheel T is coupled at least indirectly, preferably directly, to the sun wheel 6 of the planetary gear mechanism. The input E or the shaft forming or coupled to this, in a particularly advantageous embodiment, is guided by a connecting shaft which is configured as a hollow shaft 18 and forms the connection 28 between the turbine wheel T and the second element of the planetary gear mechanism 4 (here the sun wheel 6) between the turbine wheel T and.
The reverse torque converter 2 may be configured as a single-stage or multistage converter, furthermore as a single-phase or multiphase converter.
An operating medium supply and/or conduction system 12 is assigned to the reverse torque converter 2. This may be an operating medium supply and/or conduction system assigned solely to the converter, or a system assigned to several components of the power transmission device 1, or a system assigned to the power transmission device 1 or to a higher-level unit. Preferably, at least one actuating device 13 is assigned to this for filling and/or emptying.
The reverse torque converter 2 is characterized in that the impeller P and the turbine wheel T run in opposite directions. The turbine wheel T may be arranged next to the impeller P in the axial direction. Embodiments with radial arrangement are also conceivable. Furthermore, the reverse torque converter 2 comprises at least one guide wheel L. The guide wheel L is preferably stationary (single-phase converter) but may also be mounted rotatably or be supported via a freewheel device (multiphase converter). In the case depicted, the converter is configured with one-piece main elements—impeller P, turbine wheel T or guide wheel L—and with a single stage. The reverse torque converter 2 may also be configured in multiple parts, wherein then at least one main element—impeller P, turbine wheel T or guide wheel L—consists of several blade rings. Multipiece converters may furthermore be configured with a single or multiple stages. In the latter case, at least one of the main elements—impeller P, turbine wheel T or guide wheel L—consists of several blade rings, between which in the circuit another main element—impeller P, turbine wheel T or guide wheel L—is arranged.
To control and/or regulate the moment and/or rotation speed which can be transmitted via the reverse torque converter 2, the reverse torque converter 2 is configured as an adjustable converter. This function may be implemented in various ways. It is conceivable to implement this by so-called annular sliders, adjustable blades, in particular twist blades or blade segments, or devices for adjusting the fill level, in particular filling and emptying valves.
In an advantageous embodiment, the reverse torque converter 2 is designed with adjustable blades or blade segments on at least one of the blade wheels—impeller P, turbine wheel T or guide wheel L—in order to influence and control the transmission behavior, in particular the power transmission behavior and rotation speed. Quite particularly preferably, the reverse torque converter 2 is configured with adjustable blades or blade segments on the impeller P, as depicted in exemplary fashion in
In an alternative embodiment, the function of the actuating device 17 for influencing the transmission behavior may also be performed, in concentration of function, by an actuating device 13 for filling and emptying. In this case, the supply to and discharge from the working space is controlled accordingly.
Via the device 17 for influencing the transmission behavior, it is possible to control the reverse torque converter 2 in an operating range, known as the converter mode, according to the rotation speed and torque. In converter mode, part of the power is transmitted mechanically from the input E via the superposition gear mechanism 3, and a further part hydrodynamically via the reverse torque converter 2, wherein the power proportions are combined again in the superposition gear mechanism 3. In relation to a total operating range of the power transmission device 1, the possible rotation speed control range of the reverse torque converter 2 is limited. In order to expand the rotation speed control range of the power transmission device 1, according to the invention therefore a selectable, adjustable clutch is provided, in particular the control clutch 20. In a similar fashion to the converter, the control clutch 20 serves for transmitting the moment from input E to output A in a first power branch over a first rotation speed range, while the reverse torque converter 2 serves for power transmission in a second rotation speed range.
The control clutch 2 may for example be configured as a controllable friction clutch, in particular a multiplate clutch, or in a particularly preferred embodiment as shown in
The control clutch 20 comprises a first clutch part K1 which is connected at least indirectly to the input E. In
In order to be able to transmit the power via the reverse torque converter 16 in the second rotation speed range, bypassing the control clutch, the control clutch 20 is switchable or preferably bridged.
With regard to the structure and design of the control clutch as a hydrodynamic controllable clutch 16, there is a multiplicity of possibilities. This may be a clutch with a fill level control, or a clutch with a scoop tube.
In order to be able to drive the output A via the hydrodynamic clutch 16, it is furthermore necessary to support the element of the planetary gear mechanism 4 connected to the turbine wheel T and hence the hydrodynamic power branch provided in converter mode, wherein the reverse torque converter 2 is emptied in the first rotation speed range with power transmission by the control clutch 20. For this, a device 25 is provided for supporting and/or fixing the second element of the planetary gear mechanism 4, in particular the sun wheel 6 or the connection 28 between this and the turbine wheel T. The support may take place either on a stationary component 29, in particular a housing part, or, in a further embodiment, on a component which can rotate with relative rotation speed and/or in the opposite direction, for example on the planet carrier 8 of the planetary gear mechanism 4, as depicted in
In the embodiments of
In order to allow a direct drive between the third element, in particular the ring gear 5 of the planetary gear mechanism 4, and the output A, furthermore a direct drive device 19 is provided. This can be arranged as a separate selectable clutch between the shafts connected to the clutch parts K1 and K2, or directly as a bridging clutch between K1 and K2 or, in the design as a hydrodynamic controllable clutch 16, between the impeller PK and turbine wheel TK. In the embodiment according to
In the embodiments according to
According to
Alternatively, a coaxial arrangement of the output A to the hydrodynamic clutch 20 is conceivable, as shown for example in
In all embodiments, an operating medium supply system 20 is provided for filling and/or emptying the hydrodynamic components. Preferably, this is assigned in common to all hydrodynamic components, but it is also conceivable to assign this only to individual hydrodynamic components. Corresponding actuating devices at least for filling and/or emptying are assigned to each hydrodynamic component. These actuating devices are designated respectively 13 for the reverse torque converter 2, 26 for the hydrodynamic brake, and 23 for the hydrodynamic clutch 20. The device 13 for influencing the fill state or fill level comprises means for filling/emptying, preferably in the form of valve devices in the supply to and discharge from the reverse torque converter 2.
The device 23 for filling/emptying the hydrodynamic clutch 16 may either perform only the function of selection by filling and emptying, wherein then a separate actuating device 21 must be provided for influencing the transmission behavior, or may also, in concentration of function, include the actuating device 21 for influencing the transmission behavior of the control clutch 20, for example in the form of controllable valve devices and/or a so-called scoop tube in the supply to and/or discharge from the hydrodynamic clutch 16. This applies similarly to the hydrodynamic retarder 31.
To control the operating mode of the power transmission device 1, a control device 14 is provided. The control device 14 may for example be a control device assigned to the power transmission device 1. A control device is also conceivable which is assigned to the drive train 10, or to the entire system of drive train 10 and working machine 11. This device is coupled to the actuating devices for activating the individual components of the power transmission device 1. These are above all the actuating device 17 for influencing the transmission behavior of the reverse torque converter 2, the actuating device 13 for filling/emptying the reverse torque converter 2, the actuating device for activating the control clutch 20, in particular the actuating device 21 for adjusting the transmission behavior of the hydrodynamic clutch and the actuating device 23 for filling or emptying the hydrodynamic clutch 16, the actuating device 26 for operating the devices 25, and the actuating device for activating the direct drive 19. To activate the individual actuating devices, corresponding correcting variables Y13, Y17, Y19, Y21, Y23, Y26 are emitted. As an example, the following correcting variables are emitted:
On reaching the end of the control range of the control clutch 20, in particular the hydrodynamic clutch 16, this is deactivated and the reverse torque converter 2 brought into operation, as shown for example in
The basic method is characterized by the following method steps:
It is however also conceivable for further rotation speed/torque conversion devices 15 to be interposed between the superposition gear mechanism 3 and output A, here designated 15 and indicated by means of a dotted line.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2017 114 063.8 | Jun 2017 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2018/065570 | 6/13/2018 | WO | 00 |
