DE102018113272A1 - Actuator arrangement for changing a transmission ratio of a continuously variable transmission - Google Patents

Abstract

An actuator arrangement (34) is provided with a drive shaft (14) which can be coupled to a motor vehicle engine (12) for introducing a torque, a conical disk (30) received in a rotationally fixed but axially displaceable manner on the drive shaft (14) for torque transmission at one between the conical disk ( 30) and a counter-disk (32) compressed Umschlingungsmittel (20), an acting on the conical disk (30) actuator (40) for axially displacing the conical disk (30) relative to the drive shaft (14), a servomotor (36) for actuating the actuating element (40) and one with the adjusting element (40) and the servomotor (36) coupled to the transmission means (38) for translating a of the servomotor (36) applied actuating force to the actuating element (40), wherein the transmission device (38) is designed as a summation and the gear means (38) for branching off a part of the torque introduced via the drive shaft (14) to the control element (40) is additionally coupled to the drive shaft (14). This allows energy-efficient changing of the transmission ratio of a continuously variable transmission (16).

Description

The invention relates to an actuator arrangement, with the aid of which a transmission ratio of a continuously variable transmission can be changed.

Out DE 102 94 154 B4 a continuously variable transmission is known in which an axial distance of conical disks of a conical disk set by means of an actuator arrangement can be changed. In the actuator assembly, a servo motor via gear pairings of an intermediate shaft rotate a rotatably mounted on an axially displaceable conical disk actuator, which is supported via a ball screw mechanism on an axially fixed bearing, so that the conical disk can be moved axially together with the actuating element upon rotation of the actuating element to change the axial distance to a counter-disc, whereby a verpresster between the conical disc and the opposite disc belt for changing the gear ratio can be moved to another effective radius.

There is a constant need to be able to change the transmission ratio of a continuously variable transmission energy-efficient.

It is the object of the invention to show measures that enable energy-efficient changing the transmission ratio of a continuously variable transmission.

The object is achieved according to the invention by an actuator arrangement having the features of claim 1. Preferred embodiments of the invention are specified in the subclaims and the following description, which individually or in combination may represent an aspect of the invention.

According to the invention, an actuator arrangement for changing a transmission ratio of a continuously variable transmission of a motor vehicle is provided with a coupling with a motor vehicle drive shaft for introducing a torque, a rotatably but axially displaceable received on the drive shaft cone pulley for torque transmission to a pressed between the conical disk and a counter-belt entangling means on the cone pulley engaging actuator for axially displacing the conical disk relative to the drive shaft in response to a relative rotation of the actuator relative to the conical disk, a servomotor for actuating the actuator and coupled to the actuator and the actuator transmission means for translating a force applied by the actuator actuating force to the actuator , wherein the transmission device is designed as summing and the transmission device for branching a part of the via the drive shaft introduced torque is additionally coupled to the actuator with the drive shaft.

The summing gear allows the power required to adjust the axial distance of the conical disk to be diverted from the power flow passing from an automotive engine for driving drive wheels through the continuously variable transmission. Here, the knowledge is exploited that the drive shaft extends in spatial proximity to the actuator and thereby can be coupled space-saving. The power of the servomotor can be used in particular to produce and / or interrupt a torque flow from the drive shaft to the actuator. This makes it possible with a minimum use of energy for the servomotor to shift the conical disk axially to change the transmission ratio of the continuously variable transmission. If the gear ratio is not to be changed, the servomotor, preferably in an off state, in the summation of the transmission device bring about a gear state in which the transmission component connected to the drive shaft rotates substantially without load. A drag torque of the transmission device on the drive shaft can thereby be minimized. When the gear ratio is to be changed, the servo motor in the summing gear of the gear device can bring about a gear state in which a power flow from the drive shaft to the actuator can take place. In this case, in particular, at least a part of the power of the servo motor can be transmitted to the actuator. In particular, it is provided that, when the servomotor transmits its power to the control element, automatically sets a transmission state in the transmission device, in which a part of the power of the drive shaft is branched off to the actuator. The connection of the drive shaft with the aid of the transmission device designed as a summing gear makes it possible to divert power from the drive shaft for actuating the control element and to minimize the energy required to generate power in the servomotor, so that an energy-efficient changing of the transmission ratio of a continuously variable transmission is made possible.

The continuously variable transmission, also referred to as CVT transmission ("CVT" = continuously variable transmission), by changing the axial distance of an input side cone pulley to the correspondingly designed input side mating pulley and a corresponding change in the axial distance of an output side cone pulley to the correspondingly configured output side mating pulley Transmission ratio and thus the transmitted Torque and steplessly change the transmitted speed. The minimum and maximum ratio of the continuously variable transmission are defined by the minimum and maximum effective diameters of the input and output conical disk sets on the wrapping means. The shaft of the input side conical disk set may be coupled to a drive shaft of an automotive engine or form the drive shaft. The shaft of the output side conical disk set may be coupled to an output shaft for driving a drive wheel of a motor vehicle or form the output shaft.

In particular, the transmission device has a first planetary gearbox coupled to the servomotor and to the actuating element and a second planetary gearbox coupled to the drive shaft and to the first planetary gearbox. The two coupled planetary gear can be easily formed a summation, in which two independently rotatable input elements can be coupled to a common output element. In particular, the transmission device can provide a stepless transmission, so that preferably the drive shaft can be coupled to the actuator with a gear ratio between zero and a non-zero gear ratio.

Preferably, a torque flux from the servomotor to the control element extends exclusively via the first planetary gear, wherein a torque flux from the drive shaft to the actuating element extends over a part of the first planetary gear. The torque fluxes coming from the servomotor and from the drive shaft can thereby come together in the first planetary gear. Since the drive shaft usually rotates permanently, it is thus easier to divert a gradually increasing torque from the drive shaft with the help of the servomotor driven from the state. The coming of the drive shaft torque can be diverted very carefully, so that oversteer of the actuating element can be easily avoided by a coming from the drive shaft too large suddenly effective torque. This facilitates a control of the axial distance of the conical disk to the counter pulley and avoids an unstable control.

Particularly preferably, a first planet carrier of the first planetary gear is connected to a second planet carrier of the second planetary gear. The connection of the planet carrier makes it easier to circulate the second ring gear and / or the second sun gear of the second planetary gear substantially no load. The drive shaft can be easily coupled with a translation of zero to the actuator, if a change in the gear ratios is currently not provided.

In particular, a first ring gear of the first planetary gear is connected to the actuating element, wherein a first sun gear of the first planetary gear is connected to the servomotor, wherein in particular between the first sun gear and the servo motor, an intermediate ratio is provided. The first sun gear need not be positioned coaxially with a motor shaft of the servomotor. Instead, the intermediate gear allows an eccentric connection of the servomotor to the first sun gear via a gear pair with or without intermediary intermediate shaft. The servo motor can thereby be positioned in a more suitable space, so that, for example, the axial space can be kept low. In addition, a speed or torque can be over- or under-reduced by the intermediate ratio, so that the servo motor can achieve a change in the transmission ratio with a low drive power.

Preferably, a second ring gear of the second planetary gear is fixed to the drive shaft, in particular, a second sun gear of the second planetary gear is fixedly secured. The second sun gear can easily be led out of the transmission device through the first sun gear of the first planetary gear on the side facing away from the drive shaft in order to fasten and support the second sun gear with a stationary part.

Particularly preferably, the actuating element is immovably supported in the axial direction by means of a thrust bearing on the drive shaft or on the transmission device, wherein in particular the actuating element is supported on a transmission component of the transmission device secured against rotation with the drive shaft. This results in a particularly compact and space-saving construction.

In particular, the actuating element is mounted relatively rotatable to the drive shaft on the drive shaft, wherein the actuating element via a, in particular designed as a ball screw, helical gear is coupled to the conical disk, in particular between the conical disk and the actuating element, a spring element for biasing the conical disk is provided in the axial direction , The adjusting element can engage, in particular, in a space provided inside the conical disk, in order to save space there for the helical drive. The axial extent can be kept low. The spring element can by its bias a certain minimum Specify contact pressure on the belt, so that a correspondingly high maximum torque can be transmitted without slippage of the belt.

Preferably, the servomotor is designed as an electric motor. The servomotor may in particular be connected to a rechargeable motor vehicle battery. By connected via the transmission device drive shaft for the operation of the servomotor only a small electrical power is required to change the gear ratio. The servomotor can be dimensioned accordingly small, which space can be saved.

The invention further relates to a continuously variable transmission for substantially continuous variation of a transmission ratio in a drive train of a motor vehicle, with an input cone pulley set for introducing a torque, an output cone pulley set for discharging the torque and a the input bevel gear set with the Ausgangskegelscheibensatz coupled Umschlingungsmittel, in particular V-belt, wherein a gear ratio with Assistance of an actuator arrangement acting on the input cone pulley set and / or on the output cone pulley set, which can be configured and developed as described above, is adjustable. The connection of the drive shaft by means of the transmission device of the actuator arrangement designed as a summing gear makes it possible to divert power from the drive shaft for actuating the control element and to minimize the energy required to generate power in the servo motor so that an energy-efficient change of the transmission ratio of a continuously variable transmission is made possible.

• 1: ein schematisches Prinzipschaltbild eines ein Stufenlosgetriebe aufweisenden Antriebstrangs für ein Kraftfahrzeug und
• 2: ein schematisches Prinzipschaltbild einer Aktoranordnung für das Stufenlosgetriebe aus 1.

The invention will now be described by way of example with reference to the accompanying drawings with reference to preferred embodiments, wherein the features shown below, both individually and in combination may represent an aspect of the invention. Show it:

• 1 : A schematic block diagram of a continuously variable transmission having drive train for a motor vehicle and
• 2 : A schematic block diagram of an actuator arrangement for the continuously variable transmission 1 ,

The in 1 illustrated drive train 10 for a motor vehicle has an automotive engine 12 on, over a drive shaft 14 a continuously variable transmission configured as a conical-pulley transmission 16 drives. The continuously variable transmission 16 has an input cone pulley set 18 and a belt designed as a V-belt 20 Tailored output cone pulley set 22 on. The output cone pulley set 22 can that in the continuously variable transmission 16 converted torque via a differential gear 24 on two drive wheels 26 transfer. A major power flow 28 thus runs from the motor vehicle engine 12 over the continuously variable transmission 16 to the drive wheels 26 ,

The input cone pulley set 18 and the output cone pulley set 22 each have an axially displaceable cone pulley 30 on, relative to an axially fixed to the cone pulley 30 corresponding conical counter-disc 32 can be adjusted axially to the belt 20 to move to another effective radius, whereby the transmission ratio of the continuously variable transmission 16 can be varied continuously. For axial displacement of the conical disk 30 is an actuator arrangement 34 provided, preferably on the input cone pulley 18 but additionally or alternatively also acts on the output cone pulley set 22 can attack. The actuator arrangement 34 has a trained as an electric motor servomotor 36 on top of a transmission device 38 with an axially stationary but rotatable on the drive shaft 14 recorded actuator 40 is coupled. During operation of the servomotor 36 can be a regulating power flow 42 from the servomotor 36 over the transmission device 38 to the actuator 40 be transferred, wherein a rotational speed and a torque of the servomotor 36 with the help of the transmission device 38 converted to the actuator 40 can arrive. The actuator 40 is about a configured as a ball screw helical gear 44 with the cone pulley 30 coupled, so that upon rotation of the actuating element 40 the via a spline 46 rotatably but axially movable with the drive shaft 14 coupled cone pulley 30 can be displaced axially. Between the cone pulley 30 and the actuator 40 can be designed as a coil spring spring element 48 be braced, the minimum contact pressure on the belt 20 can provide and / or dampen axial shocks.

As in particular in 2 shown is the transmission device 38 designed as summing, the one with the servomotor 36 and with the actuator 40 coupled first planetary gear 50 and one with the drive shaft 14 and with the first planetary gear 50 coupled second planetary gear 52 having. The drive shaft 14 is characterized by the summation gear designed as a transmission device 38 with the actuator 40 coupled, so that from the drive shaft 14 a secondary power flow 54 over the transmission device 38 to the actuator 40 can be diverted. For this purpose, the first planetary gear 50 one with the actuator 40 connected first ring gear 56 have that over from a first planet carrier 58 stored first planet gears 60 with a first sun gear 62 is coupled. The first sun wheel 62 is about a pinion 64 with the servomotor 36 coupled, being over the coupling of the coaxial with a motor shaft 66 of the servomotor 36 connected pinion 64 with the sun wheel 62 an intermediate translation 68 can be realized. The second planetary gear 52 has a fixed to the drive shaft 14 connected second ring gear 70 on, on which the actuator 40 via a thrust bearing 72 can support relatively rotatable axially. Incidentally, the transmission device 38 be substantially free of axial forces. The second ring gear 70 is over from a second planet carrier 72 stored second planetary gears 74 with a fixed second sun gear 78 coupled. The first planet carrier 58 is with the second planetary carrier 74 connected so that the first planetary gear 50 with the second planetary gear 52 over the planet carrier 58 . 72 coupled together. About the planet carrier 58 . 72 can that of the drive shaft 14 upcoming auxiliary power flow 54 and that of the servomotor 36 next actuating power flow 42 merged and together over the first ring gear 56 to the actuator 40 be transmitted, so that a significant proportion of the axial displacement of the conical disk 30 required power from the drive shaft 14 can come and the servomotor 36 can be saved.

LIST OF REFERENCE NUMBERS

10

powertrain

12

Automotive engine

14

drive shaft

16

CVT

18

Input conical disc set

20

endless

22

Output conical disc set

24

differential gear

26

drive wheel

28

Main power flow

30

conical disk

32

counter-disk

34

actuator assembly

36

servomotor

38

transmission device

40

actuator

42

Adjusting power flow

44

helical

46

splines

48

spring element

50

first planetary gear

52

second planetary gear

54

In addition to power flow

56

first ring gear

58

first planet carrier

60

first planetary gear

62

first sun gear

64

pinion

66

motor shaft

68

between translation

70

second ring gear

72

thrust

74

second planet carrier

76

second planetary gear

78

second sun wheel

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 10294154 B4 [0002]

Claims (10)

Actuator arrangement for changing a transmission ratio of a continuously variable transmission (16) of a motor vehicle, with a drive shaft (14), which can be coupled to an automobile engine (12), for introducing a torque, a rotationally fixed but axially displaceable on the drive shaft (14) received conical disk (30) for transmitting torque to a between the conical disk (30) and a counter-disk (32) pressed belt-wrapping means (20), an actuating element (40) acting on the conical disk (30) for axially displacing the conical disk (30) relative to the drive shaft (14) in response to a relative rotation of the actuating element (40) relative to the conical disk (30), a servo motor (36) for actuating the actuating element (40) and a transmission device (38) coupled to the control element (40) and the servomotor (36) for translating an actuating force applied by the servomotor (36) to the control element (40), wherein the transmission device (38) is configured as a summation gear and the transmission device (38) is additionally coupled to the drive shaft (14) for branching part of the torque introduced via the drive shaft (14) to the control element (40). Actuator arrangement after Claim 1 characterized in that the transmission device (38) has a first planetary gear (50) coupled to the servomotor (36) and to the adjusting element (40) and a second planetary gear (52) coupled to the drive shaft (14) and to the first planetary gear (50) ) having. Actuator arrangement after Claim 2 characterized in that a torque flow (42) from the servomotor (36) to the actuator (40) extends exclusively through the first planetary gear (50), wherein a torque flux (54) from the drive shaft (14) to the actuator (40) via a part of the first planetary gear (50) extends. Actuator arrangement after Claim 2 or 3 characterized in that a first planet carrier (58) of the first planetary gear (50) with a second planetary carrier (74) of the second planetary gear (52) is connected. Actuator arrangement according to one of Claims 2 to 4 characterized in that a first ring gear (56) of the first planetary gear (50) is connected to the actuator (40), wherein a first sun gear (62) of the first planetary gear (50) is connected to the servo motor (36), in particular between the first sun gear (62) and the servo motor (36) an intermediate ratio (68) is provided. Actuator arrangement according to one of Claims 2 to 5 characterized in that a second ring gear (70) of the second planetary gear (52) with the drive shaft (14) is fixed, in particular a second sun gear (78) of the second planetary gear (52) is fixedly secured. Actuator arrangement according to one of Claims 1 to 6 characterized in that the adjusting element (40) via a thrust bearing (72) on the drive shaft (14) or on the transmission device (38) is supported immovably in the axial direction, in particular the adjusting element (40) at one with the drive shaft (14) rotatably mounted transmission component (70) of the transmission device (38) is supported. Actuator arrangement according to one of Claims 1 to 7 characterized in that the adjusting element (40) is mounted relatively rotatable to the drive shaft (14) on the drive shaft (14), wherein the adjusting element (40) via a, in particular configured as a ball screw, helical gear (44) coupled to the conical disk (30) is, in particular between the conical disk (30) and the adjusting element (40), a spring element (48) for biasing the conical disk (30) is provided in the axial direction. Actuator arrangement according to one of Claims 1 to 8th characterized in that the servomotor (36) is designed as an electric motor. Continuously variable transmission for substantially continuously varying a transmission ratio in a drive train (10) of a motor vehicle, having an input cone pulley set (18) for introducing a torque, an output cone pulley set (22) for discharging the torque, and an input bevel pulley set (18) having the output pulley set (22) coupling belt (20), in particular V - belt, wherein a transmission ratio by means of a at the input bevel gear set (18) and / or at the output bevel gear set (22) acting actuator assembly (34) according to one of Claims 1 to 9 is adjustable.

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