DE102022109875B3 - CVT transmission for a motorized two-wheeler - Google Patents

Abstract

A CVT transmission (1) for a motorized two-wheeler is proposed, comprising a variator (2) with two conical disks (4, 5) which can be displaced in relation to one another and adjusted via an electromechanical actuator (14), which actuator (14) has a two-stage transmission arrangement (16 ) whose first stage is designed as a worm gear (17) and whose second stage is designed as a rack and pinion gear (30), with a threaded spindle (18) of the worm gear (17) being acted upon by an electric motor (15), with the worm gear (17) gear element (20) that connects to the rack and pinion gear (30) and is rotatable about a pivot axis (SW), comprising a shaft (21) which, at the output of the worm gear (17), has a gear wheel segment (19) that meshes with its threaded spindle (18) and, at the input of the rack and pinion gear (30) has a gear (22) and wherein the rack and pinion gear (30) comprises a sleeve-shaped rack (24) meshing with the gear (22) and which has a shaft ( 31) surrounds.

Description

The invention relates to a CVT transmission for a motorized two-wheeler, comprising a variator with two conical disks that can be displaced relative to one another and adjusted via an actuator.

A CVT transmission for a motorcycle with adjustment of the conical disks of the variator relative to one another using centrifugal weights is described in EP 0 038 316 B1 , col. 1, lines 1 - 30.

An actuator with a two-stage gear assembly is from the DE 101 05 032 A1 , 1, i . V. with chapter [0001]. In the first gear stage, which is a worm gear, the worm wheel is acted upon by an electric motor. A gear wheel meshing with the worm wheel acts directly on a toothed rack via a second gear wheel stage. The latter elements form a second gear stage (rack and pinion gear).

The US 2002/0 034 994 A1 discloses a CVT transmission with an adjustment of the conical disks of the variator to each other via a rack and pinion gear.

Another CVT transmission, generally for a motor vehicle is from DE 199 46 336 A1 known. The transmission comprises a variator with conical pulleys, one of the conical pulleys being axially displaceable and a belt being accommodated between the conical pulleys on an adjustable radius. A pressing device ensures a frictional connection between the conical pulleys and the belt. The pressing device of this transmission after DE 199 46 336 A1 comprises forced guidance means which bring about an axial displacement of the conical disk depending on the torque to be transmitted and/or a transmission ratio to be set externally.

An Indian DE 102 22 520 A1 The automatic transmission described comprises two sets of conical disks, with an arrangement of the axes of rotation of two conical disks of at least one set of conical disks being variable in relation to one another. In this way, it should be possible to counteract a spreading of the conical disks.

Control methods and control systems for CVT transmissions are in the documents DE 10 2006 044 543 A1 and DE 10 2005 006 157 B4 described.

The EP 1 743 107 B1 discloses a coaxial electric actuator for a CVT transmission. In this case, an electric actuator includes an axially movable armature. In this case, too, a belt is provided as an encircling means.

The EP 1 413 802 B1 describes details of a pulley for a CVT transmission. Motor scooters and small cars are mentioned as possible fields of application. Furthermore, in the EP 1 413 802 B1 pointed out the fundamental possibility of moving the belt pulleys of a CVT transmission axially by means of an electronically controlled actuator.

In addition, the pamphlets DE 10 2016 118 877 A1 , DE 30 44 286 A1 , DE 10 2021 109 655 A1 and DE 103 14 107 A1 referred.

The object of the invention is to create a CVT transmission specifically for a motorized two-wheeler with an improved actuator system. There should be a particularly favorable ratio between outlay on equipment and functionality.

This problem is solved by the new features of claim 1. Accordingly, the two pulleys of the variator of the CVT transmission can be adjusted via an electromechanical actuator. The actuator comprises a two-stage gear arrangement actuated by an electric motor, the first stage of which is designed as a worm gear and the second stage as a rack and pinion gear. A threaded spindle of the worm gear is non-rotatably connected to a motor shaft of the electric motor. A gear element that connects the worm gear to the rack and pinion gear and is rotatable about a pivot axis is provided. The latter comprises a shaft, which has a gear wheel segment meshing with its threaded spindle at the output of the worm gear and a gear wheel at the input of the rack and pinion gear. The rack-and-pinion gear comprises a sleeve-shaped toothed rack which meshes with the gear wheel and surrounds a shaft which is provided for driving the conical disks which can be displaced in relation to one another. Furthermore, a sleeve is provided, which is arranged radially between the shaft and the toothed rack and is coupled to the toothed rack in a torque-proof manner by means of toothing. Finally, a bearing arrangement arranged axially between the toothed rack and the conical disks is provided for rotational decoupling between the toothed rack on the one hand and the shaft and the conical disks on the other hand.

A motor scooter in particular is intended as a motorized two-wheeler.

The actuator of the CVT transmission is thus made up of a two-stage transmission arrangement a worm gear formed as the first gear stage and a rack and pinion gear as the second gear stage. By connecting the two gear stages in series, a high reduction ratio can be achieved overall, with a low-backlash design being possible at the same time. An electric motor of a common design, for example in the form of a brushless DC motor, is suitable for actuating the threaded spindle of the worm gear.

The worm gear is connected to the rack and pinion gear according to the invention via a gear element which can be rotated about a pivot axis. The latter comprises a shaft, which has a gear wheel segment meshing with its threaded spindle at the output of the worm gear and a gear wheel at the input of the rack and pinion gear. In principle, the transmission element can be constructed in one or more parts.

According to the invention, the rack of the rack and pinion gear is in the form of a sleeve in a particularly space-saving and at the same time robust design. In doing so, it concentrically surrounds a shaft provided for driving the conical disks which can be displaced in relation to one another. There is a sleeve radially between the shaft and the toothed rack, which is coupled to the toothed rack in a torque-proof manner by means of toothing. A bearing arrangement arranged axially between the toothed rack and the conical disks is provided for rotational decoupling between the toothed rack on the one hand and the shaft and the conical disks on the other hand. The latter can in particular include a roller bearing, for example in the form of a ball bearing.

The gear at the beginning of the rack and pinion gear can also be formed by a gear segment. The pitch circle of this toothing to be attributed to the second gear stage in a typical embodiment is smaller, for example at most half as large as the pitch circle of the toothed wheel segment which is to be attributed to the worm gear. In this way, considerable forces can be introduced into the toothed rack in the longitudinal direction of the toothed rack if the displacement paths are not too great, that is to say adjustment movements of the pair of conical disks.

The shaft provided for driving the mutually displaceable conical disks can be firmly connected to one of the conical disks, while the second conical disk can be displaced in the axial direction of the shaft in order to vary the effective radius of the conical disk pair and thus the transmission ratio of the entire transmission.

A pivoting of the gear element is provided according to a development of the invention by less than a full revolution. For example, the gear element can be pivoted through an angle of at least 60° and no more than 150°.

Irrespective of the geometric relationships between different toothed elements of the two gear stages, an angle sensor can be present to detect the setting of the rotatable gear element to be assigned to both gear stages. With its help, the distance between the two driven pulleys and thus the transmission ratio of the continuously variable transmission can be determined.

• 1 Komponenten eines stufenlosen Getriebes für ein Zweirad in Explosionsdarstellung;
• 2 einen Variator des stufenlosen Getriebes in perspektivischer Ansicht;
• 3 den Variator und weitere Komponenten des stufenlosen Getriebes in teilweise geschnittener Ansicht;
• 4 bis 6 eine erste, für niedrige Geschwindigkeiten ausgelegte Variatoreinstellung in verschiedenen Darstellungen;
• 7 bis 9 eine zweite, für hohe Geschwindigkeiten ausgelegte Variatoreinstellung in Darstellungen analog 4 bis 6;
• 10 und 11 das stufenlose Getriebe in der Einstellung nach den 4 bis 6 in perspektivischen Ansichten;
• 12 und 13das Getriebe in Einstellung nach den 7 bis 9 in Ansichten analog 10 und 11.

An embodiment of the invention is explained in more detail with reference to the drawing. Show it:

• 1 Components of a continuously variable transmission for a two-wheeler in an exploded view;
• 2 a variator of the continuously variable transmission in a perspective view;
• 3 the variator and other components of the continuously variable transmission in a partially sectioned view;
• 4 until 6 a first low-speed variator setting in different representations;
• 7 until 9 a second variator setting designed for high speeds in analog representations 4 until 6 ;
• 10 and 11 the continuously variable transmission in the setting according to the 4 until 6 in perspective views;
• 12 and 13that Gear in adjustment according to the 7 until 9 analogous in views 10 and 11 .

A continuously variable transmission identified overall by the reference numeral 1 is provided for use in a motorized two-wheeler, in particular a motor scooter. The two-wheeler is powered by a combustion engine. Alternatively, the two-wheeler can have a hybrid drive, ie a combination of internal combustion engine and electric motor drive. With regard to the basic structure and the function of the continuously variable transmission 1, which is also generally referred to as a CVT transmission, reference is made to the prior art cited at the outset.

In order to vary the transmission ratio of the transmission 1 , it has a variator 2 which includes a front, actively adjustable conical disk pair 3 . Between the conical disks marked 4, 5 of the conical disk pair 3 a belt runs as the traction means 8. The conical pulley 5, which is arranged on the outside in the present case on the left-hand side of the vehicle, is provided with external teeth 7. Furthermore, 5 ribs 6 are attached to the pulley. The common central axis of the conical disks 4, 5, that is to say of the front pair of conical disks 3, is denoted by MA and is aligned in the transverse direction of the vehicle.

In addition to the front pair of conical disks 3 , there is a rear pair of conical disks 9 arranged at the level of the rear wheel, which can only be adjusted passively and thus adapts to the setting of the front pair of conical disks 3 . The rear conical disk pair 9 is formed from two conical disks 10, 11, with a housing 12 on the side of the outer conical disk 11, i.e. in the present case on the left-hand side of the vehicle, in which a pressing mechanism 13 (not shown) is arranged provides the desired axial force between the conical pulleys 10, 11. In every operating state of the transmission 1, the variator 2, together with the pressing mechanism 13, ensures that the belt 8 runs around the two pairs of conical pulleys 3, 9 with the required tension.

An electromechanical actuator 14 for adjusting the pair of conical disks 3 and thus for setting an effective radius of the conical disks 4, 5 is to be attributed to the variator 2. Part of the actuator 14 is an electric motor 15, the longitudinal axis of which is aligned in the vehicle longitudinal direction in the present case. By the electric motor 15, a two-stage, generally designated 16 gear assembly is actuated.

The first gear stage is in the form of a worm gear 17 . As an input element of the worm gear 17 there is a threaded spindle 18 which is non-rotatably connected to the motor shaft of the electric motor 15 . The output element of the worm gear 17 is in the form of a gear segment 19 . The gear wheel segment 19 is part of a gear element which can be pivoted about a pivot axis SW and is designated overall by 20 and which at the same time represents the input element of a rack and pinion gear 30 . In the present case, the pivot axis SW is aligned vertically, with the transmission element 20 being rotated by no more than 90° between the two extreme settings of the continuously variable transmission 1 . The angular position of the gear element 20 can be detected with the aid of an angle sensor 23 which is located at the upper end of the gear element 20 .

The pivotable gear element 20 also includes a shaft 21 and a gear wheel 22 arranged in the lower region of the shaft 21. All parts 19, 21, 22 of the gear element 20 are firmly connected to one another. A bearing of the transmission element 20 is not shown for the sake of clarity. The pivoting direction of the transmission element 20 is indicated by SR.

The gear 22 meshes with the teeth of a sleeve-shaped, horizontally displaceable toothed rack 24. The direction of displacement of the toothed rack 24 parallel to the central axis MA is indicated by VR. The toothed rack 24 surrounds a shaft 31 that is concentric to the central axis MA and driven by an internal combustion engine.

Arranged radially between the shaft 31 and the toothed rack 24 is a sleeve 26 which has teeth 27, 28 for non-rotatable coupling to the toothed rack 24, which is also sleeve-shaped. With the help of a bearing arrangement 29, the linear movement of the toothed rack 24 can be transmitted to the conical disk 4 driven via the shaft 31. In contrast to the conical disk 4, the conical disk 5 is rigidly connected to the shaft 31.

In the setting after the 2 until 6 as well as 10 and 11, the transmission 1 is set to the shortest possible translation. This means that the scooter runs at a low speed and at the same time a high torque is applied to the rear wheel. The other extreme case, i.e. the longest possible translation, is in the 7 until 9 and 12 and 13 illustrated. In this case, a higher vehicle speed is achieved, with the torque with which the rear wheel is driven being comparatively small.

The controller of the variator 2 processes signals supplied in particular by the angle sensor 23 . The angular position of the gear segment 19 is clearly correlated with the distance between the conical disks 4, 5 and thus also with the set transmission ratio of the transmission 1. In addition, there can be a sensor on the rear wheel of the scooter, for example in the housing 12, which measures the speed of the rear wheel is detected and also linked to the control of the variator 2. Furthermore, there are links between the activation of the variator 2 and various sensors that detect the engine speed of the internal combustion engine and the throttle valve position of the internal combustion engine. Overall, this enables fine adjustment of the transmission ratio of continuously variable transmission 1, adapted to the driving situation.

Reference List

1

continuously variable transmission

2

variator

3

front, actively adjustable pair of conical pulleys

4

cone washer

5

cone washer

6

rib

7

external teeth

8th

traction means, belts

9

rear, passively adjustable pair of conical pulleys

10

cone washer

11

cone washer

12

Housing

13

compression mechanism

14

actuator

15

electric motor

16

gear arrangement

17

Worm gear, first gear stage

18

lead screw

19

gear segment

20

Gear element, pivotable

21

Wave

22

gear

23

angle sensor

24

rack

25

connection flange

26

sleeve

27

gearing

28

gearing

29

bearing arrangement

30

Rack and pinion gear, second gear stage

31

Wave

MA

central axis

SR

pan direction

SW

pivot axis

VR

shift direction

Claims (3)

CVT transmission (1) for a motorized two-wheeler, comprising a variator (2) with two conical disks (4, 5) which can be displaced in relation to one another and adjusted via an electromechanical actuator (14), which actuator (14) has a two-stage transmission controlled by an electric motor (15 ) actuated gear arrangement (16), the first stage of which is designed as a worm gear (17) and the second stage of which is designed as a rack and pinion gear (30), a threaded spindle (18) of the worm gear (17) being non-rotatably connected to a motor shaft of the electric motor (15). , wherein a gear element (20) that connects the worm gear (17) to the rack and pinion gear (30) and is rotatable about a pivot axis (SW) is provided, comprising a shaft (21) which, at the output of the worm gear (17), has a threaded spindle (18 ) has a meshing gear wheel segment (19) and a gear wheel (22) at the input of the rack and pinion gear (30), the rack and pinion gear (30) comprising a sleeve-shaped toothed rack (24) which meshes with the gear wheel (22) and which is used to drive the conical disks which can be displaced in relation to one another (4, 5) surrounds the shaft (31) provided, with a sleeve (26) being provided, which is arranged radially between the shaft (31) and the toothed rack (24) and is non-rotatably connected to the toothed rack (24 ) is coupled and wherein for rotational decoupling between the rack (24) on the one hand and the shaft (31) and the conical disks (4, 5) on the other hand a bearing arrangement (29) arranged axially between the rack (24) and the conical disks (4, 5) is provided. CVT transmission (1) after claim 1 , wherein the gear wheel segment (19) of the transmission element (20) can be rotated about the pivot axis (SW) by an angle of at least 60° to a maximum of 150°. CVT transmission (1) after claim 1 or 2 , wherein an angle sensor (23) for detecting the setting of the gear element (20) is provided.

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