DE102006019252A1 - Electromotive actuator e.g. hand gear actuator, for e.g. vehicle, has two screws screwed together with socket heads of gear, where actuator is driven in electromotive manner, and electric motor radially fixed and gripped to socket - Google Patents

Abstract

The actuator has two screws that are screwed together with socket heads of a gear, where the actuator is provided on a base plate (14) and driven in an electromotive manner. An electric motor (3) is radially fixed and gripped to a socket from outside by a hole in the socket and a center coil in the actuator in a shaft. A spring (16) is concentrically arranged to a screw connection and operates at a lower end on a hand gear (13). A roller unit (15) driven by a ball screw, has a roller pair, where one of the rollers operates on the plate and another roller operates at the hand gear.

Description

The development of dual-clutch transmissions is currently receiving a great deal of attention from almost all vehicle manufacturers, since they promise to combine the high level of comfort of a stepped automatic transmission with the good basic efficiency of a manual transmission. In addition to the high-performance components dual clutch and wheelset, the automatic actuation of the clutch and shift elements in the transmission is of particular importance, because it significantly influences the above-mentioned criteria of comfort and efficiency. When selecting suitable actuators, very different, competing concepts are currently considered. This reflects the fact that dual-clutch transmissions are still quite young on the market and that they are facing a conceptual maturity process. First experiences about possible actuators come from the automatic gearbox as well as the automated manual transmissions. In the 1 to 9 concepts for electronic motors for the actuation of double clutches are presented.

With a in 1 shown modular concept for a wet and a dry double clutch, wherein above the indicated transmission input shaft schematically a dry and below the indicated transmission input shaft a wet dual clutch, conditions have been created for a standardization not only of the basic transmission but also for its automation. This opens up synergy possibilities for control units and actuators for both variants.

• 1. Funktion • Hohe Stelldynamik • Präzise Regelbarkeit • Definiertes Notlaufverhalten
• 2. Lebensdauer • Fahrzeuglebensdauer von 240.000 km und mehr • Wartungsfreiheit • Robustheit gegenüber allen Umgebungsbedingungen (Temperaturen, Schwingungen, Schmutz)
• 3. Integration und Bauraumbedarf • Möglichst geringer zusätzlicher Bauraumbedarf, daher möglichst hoher Getriebeintegrationsgrad • Kompakte Komponenten • Einfache Montageprozesse
• 4. Energiebedarf • Möglichst geringer Energiebedarf der Aktoren und somit möglichst geringer zusätzlicher Kraftstoffverbrauch • Zusatzanforderung bei Erweiterungswunsch zum Hybridsystem • Energiequelle unabhängig vom Verbrennungsmotor

For a transmission concept that aims to combine the best features of stepper and manual controls, the actuators for the dual-clutch transmission must meet the following technical requirements:

• 1. Function • High dynamic range • Precise controllability • Defined run-flat behavior
• 2. Lifetime • Vehicle life of 240,000 km and more • Maintenance-free • Robustness against all environmental conditions (temperatures, vibrations, dirt)
• 3. Integration and space requirements • As little additional space as possible, therefore the highest possible degree of gear integration • Compact components • Easy assembly processes
• 4. Energy requirement • As low as possible energy requirement of the actuators and thus the lowest possible additional fuel consumption • Additional requirement if the hybrid system is to be extended • Energy source independent of the internal combustion engine

In particular, the last two requirements for minimal influence on fuel consumption and the independence of the source of energy from the internal combustion engine limit the choices. It has been shown that electric motors best meet this requirement. Therefore, a kit of EC motors for driving clutch and gearbox actuators has been developed, as in 2 is shown. The sizes of these electric motors are dimensioned so that they meet the performance requirements of the Verstelldynamik for the various tasks of clutch and shift operation.

The Use of these electric motors is not on the dual-clutch transmission limited. Based on the actuators shown below can be as well actuators for automated Derive manual transmissions, transfer cases or hybrid clutches.

following a lever actuator for clutch actuation is considered in more detail.

To the predetermination comes on electric motor driven actuators the criteria integration and space requirements the greatest importance to. We are looking for solutions the if possible installation spaces close to the operating points use, so as ultimately not to unnecessarily increase the overall transmission.

Based on these considerations, an actuation concept for the double clutch has arisen in which the lever in the bell housing acts on the clutch via engagement bearings and the electric motors are screwed directly onto the bell. 3 shows a schematic representation of such a lever actuator.

The apply force for the Coupling is by a preloaded spring located in the actuator applied. This acts on the lever at the other end. Between there is a displaceable bearing point whose longitudinal movement by means of a ball screw drive by the rotation of the electric motor is produced.

wobei L als die Länge des Hebels zum Federkrafteinleitungspunkt und x als die zurückgelegte Wegstrecke des Drehpunktes vom Federkrafteinleitungspunkt definiert ist. Die Vorspannkraft der Feder (F_Feder) und das aus der Stellposition x resultierende Hebelübersetzungsverhältnis bestimmen die Einrückkraft der Kupplung (F_Kupplung).With a simple lever model that made 4 can be seen, can explain the mechanism of action of the lever actuator. It is

where L is the length of the lever for spring force line point and x is defined as the distance traveled by the pivot point from the spring force introduction point. The preload force of the spring (F _spring ) and the lever transmission ratio resulting from the setting position x determine the engagement force of the clutch (F _clutch ).

In the 5 is a lever actuator shown, the indentation is effected by Fußpunktverschiebung.

In the 5 is the lever actuator "disengaged" from left to right in the positions of the clutch (M = 0 Nm), "lever actuator attached to the clutch" (eg M = 10 Nm) and "clutch disengaged" (M = M _max ) shown.

A important requirement for the actuators for double clutches is the passive opening in case of power failure ("normally open "). Here is different the dual-clutch gearbox of the automated manual transmissions. The permissible "freezing" of the actuators ("normally stay ") in this Situation could in the double-clutch transmission to a permanent state of tension lead both couplings.

The Demand for a self-opening double clutch system has for the actuators result in the mechanical single translations in the actuator should not be self-locking, which in turn means that the electric motor in normal operation, the clutch active by continuous power must hold.

The 6a and 6b show which design features of the lever actuator this self-opening is ensured. In the case of an active motor, there must always be a positive contact angle α at the contact point between the engagement lever and the axially displaceable roller unit, as in FIG 6a shown. In a passive motor, the sum of the acting forces of spring and clutch multiplied by this angle α gives a restoring force (F _spindle ) to the ball screw. This in turn generates according to its spindle pitch a back-rotating torque (M _spindle ) on the electric motor, so that the support point, as in 6b represented, for the lever can be pushed back into its engine-near starting position. So that the electric motor does not counteract this restoring torque, the windings must be opened in the passive state.

The Continuous power of the electric motor when pressing a clutch may not to a thermal overload lead the electric motor. The limit for the continuous load is about 20 watts of electrical energy input. The profile of the engagement lever (rocking cam) must now be designed so that on the one hand the contact angle α always positive is to open the passive self to ensure, and on the other hand, it must be small enough to hold the necessary holding moment low on the electric motor.

These conditions apply to all tolerances of the clutch characteristic, taking into account the installation of the clutch and actuator in the transmission. Overall, there may be a possible characteristic shift in the order of about 50% of the engagement of the clutch in new condition. 7c shows the influence of the characteristic tolerances on the operating point of coupling and actuator.

To keep the operating point of the clutch as constant as possible, the spring should be preloaded in the lever actuator and be as soft as possible. With regard to the travel at the engagement bearing (s _engagement ) results for a given lever ratio (constant position x) as an effective spring characteristic line 10 , As a stable operating point, the intersection of this line results 10 with the respective clutch characteristic 11 or 12 ,

In the 7a to 7c the following tolerance situations are shown:

7a The coupling with the lowest clearance and the steepest characteristic 11 All tolerances are set to a maximum transmittable torque. For this purpose, the roller unit in the actuator is set to the position x _a . The angle α is just so great that the electric motor is not overloaded.

7b Now the actuator is in the same position (x _b = x _a ) with the coupling with the largest clearance and the characteristic curve 12 paired with the lowest grade. Since the counter pressure is lower due to the engagement force at the lower end of the lever, the lever rotates clockwise at a constant positioning position x and follows the clutch. Theoretically, this results in the stable operating point c), in which the contact pressure and thus the transmittable torque due to the soft spring characteristic are only slightly lower than at the operating point a).

In practice, however, the characteristic curve spread at the arithmetic limit position of the tolerances is usually so great that in this point the minimum angle α _min which is permissible for the return of the actuator is undershot. To avoid this, a lever stop is provided in the actuator, which limits the rotation at the upper end of the lever, so that a positive angle α is still ensured. The force component of the spring, which is now supported on this stop, but missing to generate the necessary engagement force on the clutch. The torque capacity is not quite enough. It adjusts the operating point b).

7c In order to achieve the necessary torque capacity of the coupling, the support point in the actuator must be moved a little further towards the indentation (position x _c ). Due to the changed lever ratio, the resulting preload and stiffness of the spring increase with respect to the engagement travel and the clutch is pressed further.

The System is designed so that the stop at arithmetic tolerance calculation only in the extreme Limit of possible Characteristics comes into play. Normally, the actuator works without this stop. In this mode, it is by the self-adjusting Balance of power capable of about 2/3 of a characteristic shift of the clutch itself auszuregeln. The lever system works like one of the electronic ones Coupling control of subordinate, mechanical P-controller with only approx. 30% permanent control deviation.

In the 8th is a possible structural design of a lever actuator shown. The mechanics is about a base plate 14 and two screws bolted to the bell bottom of the gearbox. The electric motor 3 is attached radially from the outside to the bell and engages through a hole in the bell and a centering collar in the actuator mechanism in the spindle. Concentric to the glands are the springs 16 arranged at the lower end on the lever 13 (shown in section). The reel unit 15 , driven by the ball screw, has pairs of rollers, on the one hand on the base plate 14 and on the other hand in the lever 13 run and thus represent the movable support point.

From the common core elements e-motor 3 , Ball screw and roller unit 15 Now similar actuators can be adapted to different installation spaces. In the 9a and 9b this is exemplified for a clutch bell with dry clutch ( 9a ) and a clutch bell with wet clutch ( 9b ).

The Required Leistungsseckdaten these clutch actuators are considerable. Order one for a comfortable clutch control sufficient resolution too received, the setting position of the reel unit to less than 1/10 mm can be adjusted. At the same time, the actuator must have nominal clutch characteristics in 100-120 ms the clutch completely shut down or open can. The maximum engagement forces of the Couplings can while clearly over 3000 N lie, wherein at the reel unit then due to the lever mechanism over the double of these forces is applied.

But Not only the mechanics but also the electric motors are required. You need to in critical load collectives their maximum holding torque at flanged temperatures up to 125 ° C can apply permanently.

With This performance profile makes the lever actuator an ideal combination from controllability, dynamics and efficiency for the automation of dry and wet double clutches, whereby it by the partial installation needed in the clutch bell only a minimum of additional space.

To one completely Electric motor-driven automation system for a dual-clutch transmission belongs in addition to the above-described actuators for the dual clutch and the Actuator for actuation the switching elements in the transmission.

The 10 to 25 show a wide variety of concepts for actuators for this application area.

For this purpose, electric motors from the same kit are used (see 2 ). In order to minimize the complexity and space requirements for the transmission actuation, the Active Interlock System was developed. This makes it possible to preselect gears with a common actuator in both partial transmissions in any combination.

• 1. der Schalt-Wähl-Welle mit Schaltfingereinheit und
• 2. der Antriebseinheit.

From the 10 is an actuator for both partial transmissions (Active Interlock) can be seen
The Active Interlock transmission actuator 17 consists essentially of two modules:

• 1. the shift-select shaft with shift finger unit and
• 2. the drive unit.

The shift finger unit with the shift finger 18 as well as the locking and ejector elements 21 forms the interface to the internal circuitry of the transmission. It interacts with the shift rails 19 and 20 for actuating the sliding sleeves, as in 11 shown.

The gears are engaged with the shift finger 18 analogous to the operation of manual transmissions. The special feature of the Active Interlock are the significantly wider mouths on the shift rails compared to the shift finger width 19 . 20 , This makes it possible to turn back the shift shaft in the center position and another gear with the shift finger even when the gear is engaged 18 select as in the 12 and 13 shown.

If a new gear in the same sub-transmission to be preselected (see 12 ), take over the locking and ejector elements 21 at the same time laying out a previously inserted corridor. It does not matter in which direction the Shift shaft rotates or the shift finger moves ( 13 ).

For the execution of the switching and selection movement is in each case an electric motor 22 . 23 provided as in 14 shown. The switching motor 22 assumes the in and out of the gears as well as the return movement of the shift finger 18 in the middle selection position (rotary movement of the central shift shaft). The selector motor 23 is for the positioning of the shift finger 18 in the desired alley responsible (axial movement of the shift shaft).

Based on common basic elements, such as the electric motors and the functional elements of the Active Interlock System, flexible arrangements of geared actuators can be found on the overall gearbox. At the same time, this leaves the gear designer with freedom in designing the inner circuit and in the arrangement of the shift rails 19 . 20 , The 15a and 15b show two different embodiments for the cultivation of a switching actuator to the transmission.

The 15a shows the switch actuator as a plug-in module and the 15b the switch actuator as a module for a lateral mounting.

The 1-engine gearbox actuator is as in 16b shown, a further development of the drive unit for the Acitve Interlock transmission actuation using the same shift selector shaft with shift finger unit. It is based on the idea, no longer two engines, as in 16a shown, for the different sub-functions switching and selecting to use, but, as in 16b shown, the two directions of rotation of a single electric motor.

Direction of rotation 1:

rotates the electric motor in direction of rotation 1, the shift finger is in the switching direction moved to engage the gear (red arrows in the diagram of the 1-motor actuator). In the first movement section takes place by means of the switching finger unit the laying of the previously still engaged gear in the same sub-transmission.

Direction of rotation 2:

rotates the electric motor now in the opposite direction, the shift finger first returned to the middle position and when he gets there, the voting movement closes, d. H. the positioning of the shift finger and the ejector elements in the individual shift lanes, on.

The 17 shows the internal structure of such a 1-motor gear actuator. The different phases of movement are in the 18a to 18c clarified. Core elements for the selection function of this actuator mechanism are a cam 27 that have a pin 33 on the circumference the lifting and lowering of the stem 29 causes and freewheels, which fix when changing from direction of rotation 2 in direction of rotation 1 (select in switching) the currently selected lane position by turning back the cam 27 prevent. The switching movement is via two opposing spindle nuts 32 applied, which diverge on rotation of the drive in the direction of rotation 1 on a spindle with two sections of different thread direction. Complementary cam arrangements on the two nuts 32 are arranged so that each movement of a mother 32 is transferred to a driver while the cams of the other nut 32 in grooves of the driver 28 to run. This cam-groove combination forms the shift gate profile 30 from. About the on the driver 28 located rack is the shift shaft 29 driven in rotation and thus the Schalttingereinheit 31 deflected in the switching direction from the middle position.

The 18a to 18c show the switching movement of the 1-motor gearbox actuator. In the 18b has the direction of rotation of the electric motor 26 changed. The shift finger unit 31 moves back to the middle position. This movement stops when both opposing spindle nuts 32 as far as one another are touching each other. Now only the degree of freedom of the rotation remains for the function Select and thus becomes the cam 27 driven. From the 18c it can be seen that the shift shaft 29 in the direction of selection via the cam 27 raises and lowers.

outgoing from the preselection for electric motors as drives for the actuators of double clutch and gear shift are first purely electromechanical solutions been presented. Also electrohydraulic solutions with an electric satisfy driven pump the condition of independence the actuator of the state of the internal combustion engine. Consequently, too an electrohydraulic power pack in competition of different operating systems for dual-clutch transmission to be viewed as.

• 1. Integration des elektrohydraulischen Power Packs in eine Einheit ohne teure Verbindungselemente wie Schläuche und Kabel
• 2. Integration eines kostengünstigen, tellerfederbasierten Druckspeichers anstelle der teuren und oft nicht dauerhaltbaren Gasspeicher
• 3. Vereinfachungen bei den Ventilkonzepten durch Verwendung von Ventilsitzen direkt in der Steuerplatte anstelle von Cartridgeventilen
• 4. Drehschieberventil für die Wählfunktion des Getriebeaktors an Stelle mehrerer Linearventile

While automated electromechanical actuation systems have proven to be less expensive for automated clutches and automated manual transmissions, this consideration must be re-established in the dual-clutch transmission with a further active element, the second clutch. For this it is important to use the experience of the add-on ASG system with electro-hydraulic actuation. For this the following optimization potentials are seen:

• 1. Integration of electro-hydraulic power Packs in a unit without expensive fasteners such as hoses and cables
• 2. Integration of a cost-effective, spring plate-based accumulator instead of expensive and often not sustainable gas storage
• 3. Simplification of valve concepts by using valve seats directly in the control plate instead of cartridge valves
• 4. Rotary valve for the selection function of the gear actuator instead of several linear valves

The 19 shows the hydraulic plan for an electro-hydraulic power pack of a dual-clutch transmission and raises the mentioned optimization potentials according to the above numbering (1 to 4) with the reference numerals 1 ) to 4 ).

When Further optimization potential will be the use of ATF instead of hydraulic oil as actuating fluid investigated, which in principle the possibility of a common oil circulation opened with the gear.

The rotary valve 4 ) for the dialing function is rotationally driven by an electric motor. In the individual positions of the rotary valve each shift cylinder in the transmission is so connected to the switching pressure valve that the hydraulic pressure generated by the switching pressure valve leads to the switching movement to a shift rail.

Based on 20a to 20c the function of the rotary valve for "Select" is described.

20a shows the insertion of the 1st gear. Afterwards (see 20b ) is selected by the rotary valve, the switching element of the 2nd gear and the corresponding gear is switched. This is followed accordingly 20c laying out the 1st and selecting 3rd gear.

This Valve concept for the preselection in the transmission leads to an effort minimization and is considerably simpler than comparable existing concepts. In terms of dynamics and emergency response, it is absolutely equivalent for electromechanical gearbox actuation with Active Interlock.

Gas accumulators in electro-hydraulic power packs are often weak points and are replaced in the course of the vehicle's life. Therefore, on a disc spring memory (see 2 ) in 19 ), which can store hydraulic oil by means of two disc springs on the right and left of the valve plates.

A schematic representation of a built-in power pack disc spring memory goes out 21 out.

Due to the characteristics of the disc springs used, it is possible to realize a relatively large constant pressure range, whereby the peak pressure can be reduced to 25 bar. Compared to high-pressure power packs, this means either reduced leakage at comparable gap values or comparable leakage values with extended gap values. In the case of the low-pressure power pack shown here, this advantage is exploited to the effect that, with a comparable leakage balance, considerably more cost-effective valve seats are located directly in the valve plate 36 be used.

In addition to the above-mentioned properties of the disc spring memory, such as low pressure and durability, it also has the advantage that it adapts perfectly to the space of the power pack, such as from the 21 is apparent.

Out 22 shows the entire structure of a power pack with the aforementioned features, all functions are integrated in a single module (life-resistant disc spring memory 43 , Valve block 40 with valve seats, rotary valve 41 for the dialing function, pump motor 44 , Clutch operations 42 , Pump motor 44 , Gear operations 45 )

In the previous comments on the Double clutch are also adjusting mechanisms for wear when in use been presented by dry double clutches. In the overall system optimization The question arises in how far a wear adjustment in the engagement system Advantages over the adjustment in the clutch offers. Cost and space are also with this task important boundary conditions.

Therefore, a concept for tolerance compensation and wear adjustment in the engagement system of a dual clutch has been developed. The basic structure for this adjustment is exemplified in 23 shown.

Between the operation 51 and the pickup warehouse 49 are a wear sensor 47 a sleeve defining the stroke χ ₁ to be sensed 48 and a ramp system 46 arranged. The function of the adjustment system is based on the 24a to 24d clarified. In the upper half of the four illustrations, the output system is shown without wear on the coupling, in the lower half of the output system with wear.

The 24a to 24d demonstrate:

24a Clutch in unactuated position

24b The clutch is engaged to the last sensed position, which in the initial state corresponds to the maximum torque capacity (spring compressed in the upper half). Due to additional wear (lower half), the clutch is not yet fully engaged.

24c In order to be able to transmit the necessary torque even when worn, the clutch must be further engaged. This is the wear sensor 47 moved (lower half).

24d The wear sensor 47 is backwards self-locking. The sleeve 48 abuts the sensor 47 and thus blocks the return movement of the engagement bearing 49 when disengaging the clutch. The ramp mechanism 46 is twisted by prestressed springs, spreads and fills the resulting gap between lever and sleeve 48 off (lower half).

Out 25 is a schematic representation of two self-adjusting engagement systems for a dual clutch operation.

This System is particularly interesting when the double clutch for little ones Moments (small engines) and low wear reserves very compact can be. The elimination of wear adjustments in the clutch This simplifies the clutch itself. The additional engagement travel requirement at the engagement camps as a result of wear, then compensated in the engagement system is, can be kept low.

In summary provides the dual clutch transmission in the embodiment with dry clutches currently the automatic gearbox concept with the highest potential in terms of cost and efficiency. To automate clutch and switching operations Electrically driven actuators are used.

The shown execution an electromechanical actuator for the double clutch as lever actuator offers excellent properties in terms of controllability and Dynamics. At the same time this needs Clutch actuator a minimum of auxiliary power. Through its partial integration in the clutch bell is the Aktorikanteil the overall gearbox package low. Added This clutch actuator becomes the active interlock switch actuator with equally excellent performance and minimal energy consumption. In the execution as a 1-motor gearbox actuator offers further potential for cost and space reduction.

The execution The actuator as an electro-hydraulic "power pack" is an alternative Option with comparable performance. If it succeeds, the shown Optimization points such as mechanical pressure accumulator, rotary valve As well as to realize simplified control valves, so must in the Individual case decide which actuator for the particular application a dual-clutch transmission is the better solution.

One further potential carrier to simplify a dry dual clutch system, the Displacement of wear adjustment in the engagement system be. Due to the required paths and forces is the use of such solution at low torques up to about 150 Nm conceivable.

at wet dual-clutch transmissions, as in classic automatic transmissions, the directly driven control hydraulics represent the state of the art. However, the high losses of the hydraulic compensate for a large part the efficiency advantages of the basic transmission. By the execution of wet double clutch with disc springs and engagement bearings but offers the Possibility, Again, the shown electromechanical or electro-hydraulic Actuator in combination with a low-pressure cooling oil pump use. This results a system that requires significantly less auxiliary energy Has.

Furthermore presents the featured electromotive actuator for both dry as well as wet Dual clutch transmission is the ideal basis for an extension to the hybrid system. The for the hybrid functions such as stop / start or sail operation with recuperation necessary actions in the transmission can of its own accord and independently performed by the internal combustion engine become.

The Electromotive actuators thus play a central role in the success of the dual-clutch transmission and for the extension of these transmissions to the hybrid system. She represents for the dry dual clutch transmission is a key component and offers for the wet dual-clutch transmissions have enormous potential for reducing fuel consumption. Due to their modular applicability for wet and dry couplings can be geared families with the same base gear and to the represent respective application of adapted coupling technology.

1

EC motor with a maximum of 170 watts

2

EC motor with a maximum of 110 watts

3

E-Motor

4

Kupplungsglocke

5

spring

6

Ball nut

7

roll

8th

Engaging lever

9

axial fixation

10

Spring characteristic

11

Clutch characteristic

12

Clutch characteristic

13

lever

14

baseplate with career

15

roller unit with recirculating ball nut

16

feather

17

Active Interlock transmission actuator

18

shift finger

19

shift rails (Partial transmission 1)

20

shift rails (Partial transmission 2)

21

outsize and ejection elements

22

motor (with sensor)

23

select motor (with sensor)

24

shift gate

25

Shift finger unit

26

E-Motor

27

cam (Choose)

28

takeaway (Switching)

29

shift shaft

30

Switching lanes Profile

31

Shift finger unit

32

spindle nut (opposite Gradient switching)

33

Pin code (Choose)

34

freewheel

35

casing

36

valve plate

37

fluid (vacuum)

38

Belleville spring

39

expansion volume

40

manifold (Valve seats in the block)

41

engine for rotary valve (Choose)

42

clutch controls

43

Plate spring

44

pump motor

45

Gang activities

46

ramp system

47

wear sensor

48

shell

49

engagement bearing

50

guide tube

51

activity

52

casing

53

wear adjustment Coupling 1

54

wear adjustment Coupling 2

55

Hebelaktor Coupling 2

56

guide tube

x ₁

sensierter stroke

K1

clutch 1

K2

clutch 2

Claims (1)

Actuator for actuating both dry and wet double clutches and gearbox, especially for vehicles, characterized in that this actuator is driven by an electric motor.