DE102011102184A1 - Method for controlling a hydrostatic mechanical power split transmission - Google Patents

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

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 used for example in the DE 10 2004 001 929 A1 described. The proposal is for a continuously variable ratio power split transmission comprising a hydrostatic transmission part comprising a first variable volume 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.

Another hydrostatic mechanical branching transmission is in the WO 2009/071060 A2 described, consisting of a housing, respectively, a housing composed of individual housing parts, at least one arranged within the housing of at least one drive motor, in particular an internal combustion engine, drivable drive shaft which acts on gear elements, like a pump distributor, on at least two hydraulic pumps and at least another gear has, which acts medium- or directly on an output member of a power shift, wherein at least in the region of the gear at least one coupling element is positioned, and wherein the power shift has at least one at least one, drivable in the hydrostatic circuit shaft, in the region of those 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. As speed, power and acceleration, improved efficiencies achieve that are activated in different operating conditions in each case via valves / clutches those drive elements that establish an optimal efficiency balance and by such valves are disconnected via valves / clutches such drive elements and placed in a standstill in functionally not be used for certain operating areas, but the overall efficiency, eg. B. 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 controlled so that via the at least one clutch, an additional mechanical power branch from the drive motor to 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 within the phase of an exclusively mechanical driving operation, the electronic unit controls at least one valve so that at least one clutch of the hydraulic motor outgoing hydrostatic branch is coupled to the ring gear and at least one valve is controlled so that an associated clutch the degree of freedom of the ring gear to drive via the hydraulic motor ensured.

According to a further aspect of the invention, it is proposed that within the phase of a hydrostatic-mechanical driving operation via the electronic unit at least one valve is controlled, that is coupled via at least one clutch, the ring gear with the sun gear frictionally in a blocking 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 electronics 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 of exclusively hydrostatic in the hydrostatic -mechanical driving operation is done schaltstoßarm.

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 such that the switching operation takes place in a low-impact manner.

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 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 is 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 blocking state. Under a blocking state, the expert understands a state in which two of the arranged within a planetary gear three shafts are firmly connected, with the result that the three shafts of the planetary gear frictionally connected together rotate as a block, without relative speeds or without internal frictional losses.

• – rein hydraulisch mit abgeschalteter mechanischer Antriebswelle
• – leistungsverzweigt, d. h. hydraulisch angetrieben und mit mechanisch zugeschalteter Antriebswelle
• – rein mechanisch bei wahlweise geschaltetem Blockierungszustand des Planetengetriebes und/oder bei wahlweiser Abschaltung des hydrostatischen Leistungszweiges

betrieben werden kann.The provided in the power split transmission valves / clutches / brakes can be operated so that the transmission either

• - purely hydraulic with disconnected mechanical drive shaft
• - Power split, ie hydraulically driven and mechanically switched drive shaft
• - Purely mechanically when selectively switched blocking state of the planetary gear and / or selective 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.

If the hydraulic motor is arranged inside the housing, it is proposed according to a further idea of the invention to design the hydraulic motor without its own housing body. The movable drive elements of the hydraulic motor can therefore - be positioned outside of 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 power split transmission according to the invention 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:

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

3 Schematic diagram of the operation of the power split transmission according to the invention.

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

The power split transmission 1 according to 1 includes a housing 2 , Which has a shaft formed in this example as a propeller shaft 8th is mechanically driven. A trained as an internal combustion engine drive motor 3 drives a drive shaft 4 on, on the one gear element 5 is directly attached and with another gear element 24 meshes, which in turn is the wave 8th drives. The gear element 5 is also available with a gear 12 in operative connection, wherein the gear elements 5 . 12 hydraulic pumps 9 and 14 and the hydraulic pump 9 at the power split transmission 1 , respectively their housing 2 , mounted hydraulic motor 16 drives.

The hydraulic motor 16 can also reduce the installation space inside the housing 2 arranged and in this design as a caseless hydraulic motor 16 be used.

Within the power split transmission 1 , respectively their housing 2 , there is a planetary gear 31 , consisting essentially of ring gear 11 , Planets 30 , Sun wheel 42 and a jetty 32 , Furthermore, the power split transmission includes 1 , respectively their housing 2 , the drive shaft 41 for hydrostatic operation via the hydraulic motor 16 ,

In the phase of a first driving range with usually low speeds and high traction or torque requirement drives the hydraulic motor 16 on the sun wheel 42 , being a brake 34 is positively connected to the ring gear 11 against the case 2 to pinch while another clutch 29 opened and another clutch 43 is closed. In this operating state drives the hydraulic motor 16 over the gears 26 . 22 the sun wheel 42 on, so over the jetty 32 the gears 18 . 19 the output shaft 20 drive. In this operating state is also in the power split transmission 1 introduced clutch 13 open, so no mechanical power flow across the shaft 8th or the drive shaft 25 , z. B. a propeller shaft, on which also in the power split transmission 1 existing gear 22 can be done. In this first driving range, with low speeds and high traction and torque requirements, the high torque capacity of the hydrostats 9 . 16 exploited, as well as their possibility of high power delivery even at speeds in the range of n = 0 U / min. Good controllability of hydrostatics 9 . 16 allows it, the drive motor 3 operate optimized in terms of speed and performance.

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. When reaching a sufficiently high speed of the sun gear 42 or the gear 22 , In this first driving range, the mechanical power branch of the drive motor 3 over the clutch 13 on the gears 21 . 22 connected. In this operating state, therefore, the first speed range of the power split transmission already becomes 1 operated both hydraulically and mechanically.

With increasing vehicle speed and the resulting limited traction or torque requirement, the high torque capacity of the hydrostats 9 . 16 steadily less needed, so the hydrostatics 9 . 16 depending on the current speed, can be back-regulated and decoupled. To increase the efficiencies is thereby, depending on the required power or the required torque, the hydraulic motor 16 over the clutch 43 Switched off and shut down to avoid drag losses. Initially, a phase of the hydrostatic-mechanical power split is set and transferred with increasing speed, to optimize the efficiencies, in an exclusively mechanical operation.

In the middle speed range, the power split becomes the optimum speed and / or power setting of the drive motor 3 set by a brake 34 and another clutch 43 solved as well as the clutch 13 and the clutch 29 getting 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 , Wave 8th and drive shaft 25 , Clutch 13 and gear 22 on the sun wheel 42 of the planetary gear 31 and on the other hand, the mechanical power of the drive motor 3 Hydrostatically via the hydraulic pump 9 converted and on the hydraulic motor 16 passed, the hydraulic motor 16 now the ring gear 11 for a while 41 , Clutch 29 , Gear 44 and gear 23 drives. The power of the mechanical strand and the hydrostatic power are in the planetary gear 31 summed up and onto the jetty 32 directed. The speeds of the ring gear 11 and the sun wheel 42 are added here in the manner of a superposition gear and the sum of both speeds results in the planetary gear output speed at the bridge 32 that directly proportional to the speed of the output shaft 20 or the resulting vehicle speed determined. The adjustment of the speed of the ring gear 11 This is done via the well-controllable hydraulic motor 16 so made that, looking at the required vehicle speed, the speed of the sun gear 42 and thus the directly proportional speed of the drive motor 3 In CVT mode (Continuous Variable Transmission) efficiency and / or performance optimized is set.

In the last and high speed range is exclusively driven mechanically by the hydrostatic drive 9 . 16 Power controlled against P = 0 kW and the planetary gear 31 completely over the couplings 29 and 43 is placed in a blocking operation. In this case, the hydraulic pump 9 not used for driving and optionally decoupled to avoid drag losses via a clutch, not shown.

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

3 shows a schematic diagram of the operation of the power split transmission 1 , As more elements compared to the 1 and 2 are an electronics unit 10 , Valves 15 . 17 . 27 . 28 and 33 shown. 3 shows the configuration with control and control elements, the driving areas are carried out in the same way as in the 1 and 2 described. For recording the current speed and power of the drive motor 3 and optionally for detecting the operating parameters of the hydrostats 9 . 16 becomes an electronics unit 10 intended. The electronics unit 10 Optionally also for controlling the drive motor 3 and the hydrostat 9 . 16 be used. In addition, the electronics unit 10 for electrical control of the valves 15 . 17 . 27 . 28 . 33 used, which in turn couplings 13 . 29 . 36 . 43 turn. Depending on the currently measured operating parameters, such. B. the speed and the power of the drive motor 3 and the speed and the speed change and the pressures of the hydrostats 9 . 16 and the speed and speed change of the output shaft 20 or associated transmission elements, are from the electronics unit 10 the valves 15 . 17 . 27 . 28 . 33 controlled, in turn, the clutches 13 . 29 . 36 . 43 turn.

LIST OF REFERENCE NUMBERS

1

Power split transmission

2

casing

3

Drive motor (internal combustion engine)

4

drive shaft

5

gear member

6

gear

7

wave

8th

Shaft (PTO shaft)

9

hydraulic pump

10

electronics unit

11

ring gear

12

gear

13

clutch

14

hydraulic pump

15

Valve

16

hydraulic motor

17

Valve

18

gear

19

gear

20

output shaft

21

gear

22

gear

23

gear

24

gear member

21/23

gear stage

26/18

gear stage

25

drive shaft

26

gear

27

Valve

28

Valve

29

clutch

30

planet

31

planetary gear

32

web

34

brake

35

gear

36

clutch

37

gear

41

drive shaft

42

sun

43

clutch

44

gear

45

gear

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102004001929 A1 [0002]
• WO 2009/071060 A2 [0003]

Claims (8)

Method for controlling a hydrostatic-mechanical power split transmission ( 1 ), which 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 coupling ( 13 . 29 . 36 . 43 ), at least one valve ( 15 . 17 . 27 . 28 . 33 ) as well as several gear elements ( 21 . 22 ), whereby by appropriate control of the valve ( 15 . 17 . 27 . 28 . 33 ) and the clutch ( 13 . 29 . 36 . 43 ) via the electronics 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 exclusively hydrostatic driving operation the current rotational speed and / or the current power and / or the current acceleration of the drive motor ( 3 ), respectively determined and sent 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 controlled 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 wheel ( 42 ) of the planetary gear ( 31 ) is brought about. A method according to claim 1, characterized in that at the end of the phase of the hydrostatic-mechanical driving operation, the electronic unit ( 10 ) at least one valve ( 28 ) so that via the clutch ( 43 ) of the hydraulic motor ( 16 ) outgoing hydrostatic power branch from the sun gear ( 42 ) is decoupled. A method according to claim 2, characterized in that at the end of the phase of the exclusively mechanical driving operation, the electronic unit ( 10 ) at least one valve ( 33 ) so that via at least one clutch ( 29 ) of the hydraulic motor ( 16 ) outgoing hydrostatic power branch on the ring gear ( 11 ) and at least one valve ( 27 ) is controlled so that a clutch ( 34 ) the degree of freedom of the ring gear ( 11 ) to the drive via the hydraulic motor ( 16 ) guaranteed. A 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 controlled so that via at least one clutch ( 29 . 43 ) the ring gear ( 11 ) with the sun wheel ( 42 ) non-positively in a blocking operation of the planetary gear ( 31 ) is coupled. Method according to one of claims 1 to 4, characterized in that when changing from an exclusively hydrostatic 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 speed of the hydraulic motor ( 16 ) is changed so that the switching process is carried out from the purely hydrostatic in the hydrostatic-mechanical driving mode schstoßstoßarm. Method according to one of claims 1 to 5, characterized in that when changing from a hydrostatic-mechanical driving operation to an exclusively hydrostatic driving operation via the electronic unit ( 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. Method according to 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 speed of the hydraulic motor ( 16 ) is changed so that the switching operation takes place schaltstoßarm. Method according to one of claims 1 to 7, characterized in that when changing from a hydrostatic-mechanical driving operation to an exclusively mechanical driving operation via the electronic unit ( 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.

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