WO2012095077A1

WO2012095077A1 - Method for controlling a hydrostatic mechanical power split transmission

Info

Publication number: WO2012095077A1
Application number: PCT/DE2011/002147
Authority: WO
Inventors: Detlef Tolksdorf
Original assignee: Hytrac Gmbh
Priority date: 2011-01-12
Filing date: 2011-12-20
Publication date: 2012-07-19
Also published as: DE102011102184A1

Abstract

The invention relates to a method for controlling a hydrostatic power split transmission, which contains as components at least one electronic unit, at least one planetary gear unit, at least one hydraulic pump, at least one hydraulic motor, at least one drive motor, at least one drive shaft, at least one output shaft, at least one clutch, at least one valve and a plurality of gear elements, wherein an exclusively hydrostatic driving mode, a hydrostatic/mechanical driving mode and an exclusively mechanical driving mode can be implemented by appropriate control of the valve and of the clutch via the electronic unit, wherein within the phase of the exclusively hydrostatic driving mode the current speed and/or the current power and/or the current acceleration of the drive motor is measured or determined and relayed to the electronic unit, and the at least one valve is controlled on the basis of the respective measured values via the electronic unit so that an additional mechanical power branch from the drive motor to the sun gear of the planetary gear unit is implemented via the at least one clutch.

Description

Method for controlling a hydrostatic mechanical

Power split transmission

The invention relates to a method for controlling a hydrostatically-mechanical power split transmission comprising as components at least one electronic unit, at least one planetary gear, at least one hydraulic pump, at least one hydraulic motor, at least one drive motor, at least one drive shaft, at least one output shaft, at least one clutch, at least one valve as well as several gear elements.

A hydrostatic mechanical power split transmission is described for example in DE 10 2004 001 929 A1. The proposal is for a continuously variable ratio power split transmission comprising a hydrostatic transmission part consisting of a first variable-rate hydrostatic unit and a second constant-volume hydrostatic unit and a mechanical transmission part comprising a summation gear and a range gearbox in which the summation gear and the range gearbox are off-axis are arranged to the hydrostatic units.

A further hydrostatically mechanical line branching transmission is described in WO 2009/071060 A2, comprising a housing, respectively a housing composed of individual housing parts, at least one drive shaft which can be driven by at least one drive motor, in particular an internal combustion engine, and which is driven by gear elements, in the manner of a pump distributor gear, acts on at least two hydraulic pumps and has at least one further gear which acts directly on an output member of a power shift transmission, wherein at least in the region of the gear at least one coupling element is positioned, and wherein the power shift at least one of at least a, in the hydrostatic circuit driven shaft has, in the area of

CONFIRMATION COPY Clutches, brakes, components of a single-stage planetary gear and the like components are provided, wherein the output element of the power shift transmission is connected to at least one output shaft.

The aim of the subject invention is to provide a method for controlling a hydrostatic mechanical power split transmission, which is suitable, depending on the current operating parameters such. Speed, power and acceleration, improved efficiencies achieve that are activated in different operating conditions in each case via valves / clutches those drive elements that justify an optimal efficiency balance and by such valves are disconnected and stopped by means of valves / clutches such drive elements in certain operating areas are not functionally used, but the overall efficiency, eg by drag losses of hydraulic motors, could worsen.

This object is achieved by a method for controlling a hydrostatically mechanical power split transmission comprising as components at least one electronic unit, at least one planetary gear, at least one hydraulic pump, at least one hydraulic motor, at least one drive motor, at least one drive shaft, at least one output shaft, at least one clutch, at least includes a valve and a plurality of gear elements, wherein by appropriate control of the valve and the clutch via the electronics unit exclusively hydrostatic driving, hydrostatic mechanical driving and exclusively mechanical driving can be brought about, and wherein within the phase of exclusively hydrostatic driving the current speed and / or the current power and / or the current acceleration of the drive motor measured, respectively determined and forwarded to the electronic unit u nd in response to the respective measured values via the electronic unit, the at least one valve is so controlled that over the at least one Clutch an additional mechanical power branch from the drive motor on the sun gear of the planetary gear is brought about.

Advantageous developments of the subject invention can be found in the associated dependent claims.

Within the phase of a hydrostatic-mechanical driving operation, the electronic unit can control at least one valve in such a way that the hydrostatic power branch emanating from the hydraulic motor is decoupled from the sun gear via an associated clutch.

It is also possible that, during the phase of an exclusively mechanical driving operation, the electronic unit controls at least one valve such that at least one clutch couples the hydrostatic power branch emanating from the hydraulic motor to the ring gear and at least one valve is activated so that an associated clutch ensures the degree of freedom of the ring gear for driving via the hydraulic motor.

A wetteren thought of the invention according to is proposed that within the phase of a hydrostatic-mechanical driving operation via the electronics unit at least one valve is controlled so that at least one clutch, the ring gear is frictionally coupled to the sun gear in a forced operation of the planetary gear.

In addition, it is conceivable that when changing from an exclusively hydrostatic drive to a hydrostatic-mechanical drive via the electronic unit, the speed of the drive motor or the drive shaft and / or the rotational speed of the hydraulic motor is changed so that the switching process from exclusively hydrostatic in the hydrostatic mechanical Driving mode is low-impact. It may also be advantageous that when changing from a hydrostatic-mechanical driving operation to an exclusively hydrostatic driving operation via the electronic unit, the rotational speed of the drive motor or the drive shaft and / or the rotational speed of the hydraulic motor is changed so that the switching operation takes place with low-switching operation.

In a further development of the subject invention, it may be appropriate when changing from an exclusively mechanical driving to a hydrostatic-mechanical driving operation via the electronic unit, the rotational speed of the drive motor or the drive shaft and / or the rotational speed of the hydraulic motor is changed so that the switching is geschaltstoßarm.

Finally, it is also conceivable that when changing from a hydrostatic-mechanical driving operation to an exclusively mechanical driving operation via the electronic unit, the rotational speed of the drive motor or the drive shaft and / or the rotational speed of the hydraulic motor is changed so that the switching operation takes place schaltstoßarm.

The powershift transmission can be driven directly or indirectly by at least one drive motor, in particular an internal combustion engine, via a drive shaft provided with at least one clutch, which can be selectively switched either directly to the sun gear of the planetary gear or selectively non-positively engaged, the planetary gear optionally can be switched via at least one clutch in a forced running. Under a forced operation, the expert understands a state in which the movement of one of the three shafts of the planetary gear defines the movement of the two remaining shafts of the planetary gear. In gear theory, this is described according to the "Grübler equation" with the degree F = 1. The measures provided for in the area of the power split transmission valves / clutches / brakes can be operated so that the transmission either purely hydraulically disengaged with disconnected mechanical drive shaft, ie hydraulically driven and mechanically switched drive shaft purely mechanically selectively switched forced operation of the planetary gear and / or at wahlweiser Shutdown of the hydrostatic power branch can be operated.

In addition, the preferably individual hydraulic motor can optionally be coupled to the sun gear and / or to the ring gear.

The hydraulic motor can also be disconnected via at least one corresponding clutch from the planetary gear.

Furthermore, there is the possibility that the hydraulic motor in the decoupled state is thereby brought to a standstill that the delivery volume of the hydraulic pump is down regulated.

Furthermore, it is possible to arrange the hydraulic motor within the housing. As a result, an extremely space-saving design of erfindungsmäßen power split transmission is brought about.

Depending on the design of the power split transmission, the hydraulic motor may also be positioned outside the housing, provided that the installation conditions, within a vehicle, such as a wheel loader to leave this. Is the Hydra _. ulikmotor disposed within the housing, according to another idea of the invention, proposed to form the hydraulic motor without its own housing body. The movable drive elements of the hydraulic motor can therefore - be positioned outside a housing oil sump - to avoid churning losses. The necessarily provided in a housing for a hydraulic motor leakage oil connections for cooling the movable drive elements are now unnecessary, since oil from the housing oil sump can be used, by means of which the movable drive elements of the caseless hydraulic motor are molded. By avoiding churning losses, a considerable increase in the overall efficiency of the power split transmission can be brought about.

According to a further aspect of the invention, the further (mechanical) power branch can be switched to the sun gear in a power-adaptive and / or speed-adaptive and / or acceleration-adaptive manner via an associated clutch.

In addition, it is proposed that the further (mechanical) power branch can be switched to the sun gear in such a way that the internal combustion engine can be operated optimized for fuel consumption and / or with optimized performance.

It is also conceivable that the hydraulic motor is power-adaptive and / or speed-adaptive and / or acceleration-adaptive via a clutch to the sun gear switchable.

Furthermore, it may be useful in certain operating areas of the vehicle to switch the hydraulic motor power-adaptive and / or speed-adaptive and / or acceleration-adaptive via a clutch to the ring gear. Since equipped with the invention Lelstungsverzweigungsgetriebe equipped vehicles, such as wheel loaders, dumpers, tractor or the like, not always only drive forward, there is also the possibility to provide a Reversierstufe in the drive shaft, which reverses the direction of rotation of the sun gear via a clutch.

The subject invention is illustrated by means of an embodiment in the drawing and will be described as follows. Show it:

Figures 1 and 2 are schematic diagrams of the hydrostatic mechanical power split transmission according to the invention with different structure of the drive elements;

Figure 3 schematic diagram of the operation of the invention

Power split transmission.

Figures 1 and 2 show schematic diagrams of the power split transmission 1 according to the invention with different structure of the drive elements.

The Lelstungsverzweigungsgetriebe 1 according to Figure 1 includes a housing 2 which is mechanically driven by a shaft 8 formed in this example as a propeller shaft. A trained as an internal combustion engine drive motor 3 thereby drives a drive shaft 4, on which a gear member 5 is directly attached and meshes with a further gear member 24, which in turn drives the shaft 8. The gear member 5 is also in operative connection with a gear 12, wherein the gear elements 5,12 hydraulic pumps 9 and 14 and the hydraulic pump 9 drives the Lelstungsverzweigungsgetriebe 1, respectively the housing 2, mounted hydraulic motor 16. The hydraulic motor 16 can also be arranged within the housing 2 to reduce the installation space and used in this design as a housing-less hydraulic motor 16.

Within the power split transmission 1, respectively the housing 2, there is a planetary gear 31, consisting essentially of ring gear 1 1, planet 30, sun gear 42 and a web 32. Furthermore, the power split transmission 1, respectively the housing 2, the drive shaft 41 for a hydrostatic operation via the hydraulic motor 16.

In the phase of a first driving range with usually low speeds and high tractive force or torque demand drives the hydraulic motor 16 to the sun gear 42, wherein a brake 34 is non-positively connected to clamp the ring gear 1 1 against the housing 2, while a weather clutch 29 is opened and another clutch 43 is closed. In this operating state, the hydraulic motor 16 drives the sun gear 42 via the gears 26, 22, so that the toothed wheels 18, 19 drive the output shaft 20 via the web 32. In this operating state, the clutch 13 likewise engaged in the power split transmission 1 is opened, so that no mechanical power flow via the shaft 8 or the drive shaft 25, e.g. a propeller shaft, which can also be done in the power split transmission 1 existing gear 22. In this first driving range, with low speeds and high tractive force or torque requirement, the high torque capacity of the hydrostats 9,16 is exploited, as well as their possibility of high power development even at speeds in the range of n = 0 U / min. The good controllability of the hydrostat 9,16 allows it to operate the drive motor 3 speed and performance optimized.

For this reason, the known efficiency disadvantages of hydrostatics, in the sense of a holistic consideration for low speeds within this first speed range in the background in comparison to the mechanics. Upon reaching a sufficiently high speed of the sun gear 42 or of the toothed wheel 22, the mechanical power branch is switched by the drive motor 3 via the clutch 13 to the gears 21, 22 in this first driving range. In this operating state, therefore, the first speed range of the power split transmission 1 is already operated both hydraulically and mechanically.

With increasing vehicle speed and the resulting limited traction or torque requirement, the high torque capability of the hydrostatic units 9, 16 is steadily less required, so that the hydrostatic units 9, 16 can be regulated back and decoupled depending on the current speed. To increase the efficiencies, the hydraulic motor 16 is switched off and shut down via the clutch 43 to avoid drag losses, depending on the required power or the required torque. In this case, a phase of the hydrostatic-mechanical power split is initially set and transferred with increasing speed, to optimize the efficiencies, in an exclusively mechanical operation.

In the middle speed range, the power split for optimal speed and / or power adjustment of the drive motor 3 is set by a brake 34 and a further clutch 43 is released and the clutch 13 and the clutch 29 are closed. In this operating state, the power of the drive motor 3 on the one hand via the mechanical strand drive shaft 4, gear elements 5 and 24, shaft 8 and drive shaft 25, clutch 13 and gear 22 is directed to the sun gear 42 of the planetary gear 31 and on the other hand, the mechanical power of the drive motor. 3 converted hydrostatically via the hydraulic pump 9 and passed to the hydraulic motor 16, wherein the hydraulic motor 16 now the ring gear 1 1 via shaft 41, clutch 29, gear 44 and gear 23 drives. The power of the mechanical strand and the hydrostatic power are summed in the planetary gear 31 and directed to the web 32. The rotational speeds of the ring gear 11 and the sun gear 42nd are summed in the manner of a superposition gear and the sum of both speeds results in the planetary gear output speed at the web 32, which determines the speed of the output shaft 20 and the resulting vehicle speed directly proportional. The setting of the rotational speed of the ring gear 1 1 is made via the well-controllable hydraulic motor 16 so that in view of the required vehicle speed, the speed of the sun gear 42 and thus the directly proportional speed of the drive motor 3 in the CVT mode (Continuous Variable Transmission) Efficiency and / or performance optimized.

In the last and high speed range is driven only mechanically by the hydrostat 9,16 are controlled in terms of performance against P = 0 kW and the planetary gear 31 is completely offset via the clutches 29 and 43 in a forced run. In this operating case, the hydraulic pump 9 is not used for driving and optionally decoupled to avoid drag losses via a coupling, not shown.

Figure 2 shows another configuration of the drive elements, wherein the driving areas are carried out in the same manner as described in Figure 1. To realize the reverse drive with the mechanical path but in addition a Reversierstufe, consisting of a gear 35, a clutch 36 and gears 45,37, provided in the region of the drive shaft 25 to selectively change the direction of rotation of the drive shaft.

Figure 3 shows a schematic diagram of the operation of the power split transmission 1. As a further elements with respect to Figures 1 and 2, an electronic unit 10, valves 15,17,27,28 and 33 are shown. Figure 3 shows the configuration with control and control elements, wherein the driving ranges are carried out in the same manner as described in Figures 1 and 2. For detecting the current rotational speed and power of the drive motor 3 and optionally for detecting the operating parameters of the hydrostats 9, 16, an electronic unit 10 is provided. The electronics unit 10 can optionally also be used to control the drive motor 3 and the hydrostat 9,16. In addition, the electronic unit 10 can be used for the electrical control of the valves 15,17,27,28,33, which in turn switch clutches 13,29,36,43. Depending on the currently measured operating parameters, such as the speed and power of the drive motor 3 and the speed and the speed change and the pressures of the hydrostat 9,16 and the speed and speed change of the output shaft 20 or associated transmission elements, are from the electronic unit 10 the Valves 15, 17,27,28,33 driven, which in turn switch the clutches 13,29,36,43.

LIST OF REFERENCE NUMBERS

1 power split transmission 27 valve

2 housing 28 valve

3 drive motor (Brennkraftmasch 29 clutch

4 drive shaft 30 planet

5 gear member 31 planetary gear

6 gear 32 bridge

7 wave

8 shaft (drive shaft) 34 brake

9 Hydraulic pump 35 Gear

10 Electronics unit 36 Coupling

1 1 ring gear 37 gear

12 gear

13 clutch

14 hydraulic pump

15 valve 41 drive shaft

16 hydraulic motor 42 sun gear

17 valve 43 coupling

18 gear 44 gear

19 gear 45 gear

20 output shaft

21 gear

22 gear

23 gear

24 gear element

21/23 gear stage

26/18 gear stage

25 drive shaft

26 gear

Claims

claims

1. A method for controlling a hydrostatic-mechanical power split transmission (1) comprising as components at least one electronic unit (10), at least one planetary gear (31), at least one hydraulic pump (9,14), at least one hydraulic motor (16), at least one drive motor (3), at least one drive shaft (25), at least one output shaft (20), at least one clutch (13, 29, 36, 43), at least one valve (15, 17, 27, 28, 33) and a plurality of gear elements (21 , 22), wherein by appropriate control of the valve (15, 17,27,28,33) and the clutch (13,29,36,43) via the electronic unit (10) an exclusively hydrostatic driving operation, a hydrostatic-mechanical driving operation and an exclusively mechanical driving operation can be brought about, such that within the phase of the exclusively hydrostatic driving operation, the current rotational speed and / or the current power and / or the current acceleration of the drive bsmotors (3) measured, respectively determined and forwarded to the electronic unit (10) and depending on the respective measured values via the electronic unit (10), the at least one valve (15,17,27,28,33) is driven so that via the at least one clutch (13,29,36,43) an additional mechanical power branch from the drive motor (3) on the sun gear (42) of the planetary gear (31) is brought about.

2. The method according to claim 1, characterized in that at the conclusion of the phase of the hydrostatic-mechanical driving operation, the electronic unit (10) at least one valve (28) controls so that via the clutch (43) of the hydraulic motor (16) outgoing hydrostatic power branch from the sun gear (42) is decoupled.

3. The method according to claim 2, characterized in that the conclusion of the phase of exclusively mechanical driving the Electronic unit (10) at least one valve (33) controls so that at least one clutch (29) of the hydraulic motor (16) outgoing hydrostatic power branch is coupled to the ring gear (1 1) and at least one valve (27) is driven so a coupling (34) ensures the degree of freedom of the ring gear (1 1) for driving via the hydraulic motor (6).

4. The method according to claim 3, characterized in that within the phase of a hydrostatic-mechanical driving operation via the electronic unit (10) at least one valve (28,33) is driven so that at least one clutch (29,43) the ring gear ( 1 1) with the sun gear (42) non-positively in a forced operation of the planetary gear (31) is coupled.

5. The method according to any one of claims 1 to 4, characterized in that when changing from a purely hydrostatic driving to a hydrostatic-mechanical driving operation via the electronic unit (10), the rotational speed of the drive motor (3) or the drive shaft (25) and / or the speed of the hydraulic motor (16) is changed so that the switching operation takes place from the exclusively hydrostatic in the hydrostatic-mechanical drive mode schstoßstoßarm.

6. The method according to any one of claims 1 to 5, characterized in that when changing from a hydrostatic-mechanical ferry to an exclusively hydrostatic driving operation via the electronic unit (10), the rotational speed of the drive motor (3) or the drive shaft (25) and / or the speed of the hydraulic motor (16) is changed so that the switching operation takes place schaltstoßarm.

7. The method according to any one of claims 1 to 6, characterized in that when changing from an exclusively mechanical driving operation to a hydrostatic-mechanical driving operation via the electronic unit (10) the speed of the drive motor (3) or the drive shaft (25) and / or the rotational speed of the hydraulic motor (16) is changed so that the switching operation takes place schaltstoßarm.

8. The method according to any one of claims 1 to 7, characterized in that when changing from a hydrostatic-mechanical driving operation to an exclusively mechanical driving on the Elektronikeinhett (10) the speed of the drive motor (3) or the drive shaft (25) and / or the speed of the hydraulic motor (16) is changed so that the switching operation takes place schaltstoßarm.