WO2016139108A1

WO2016139108A1 - Cvt transmission featuring improved controllability

Info

Publication number: WO2016139108A1
Application number: PCT/EP2016/053912
Authority: WO
Inventors: Rudolf Eydam
Original assignee: Robert Bosch Gmbh
Priority date: 2015-03-05
Filing date: 2016-02-25
Publication date: 2016-09-09
Also published as: TW201641849A; DE102015203899A1

Abstract

The invention relates to a CVT transmission comprising a V-pulley (2) that includes a stationary cone pulley (20) and an axially movable cone pulley (21), further comprising an adjustment device (5) for adjusting a position of the axially movable cone pulley (21), said adjustment device comprising: a bearing bush (8) on the axially movable cone pulley (21); a bearing arrangement (7) between the axially movable cone pulley (21) and the bearing bush (8); a spindle drive (3) having a spindle (30) and a spindle nut (31); a lever (4) that connects the spindle nut (31) to the bearing bush (8); and a servo drive (50) for driving the spindle drive (3). The CVT transmission also comprises a control unit (6) designed to actuate the adjustment device (5) in order for the position of the axially movable cone pulley (21) to be changed.

Description

description

title

CVT transmission with improved controllability state of the art

The present invention relates to a CVT transmission (continuously variable transmission) with a significantly improved controllability and controllability. CVT transmissions are different from the prior art

Embodiments known. Due to the continuously variable transmission suitable ratios can be achieved in vehicles in each case in comparison with gears with fixed gears. A special

Application of such CVT transmissions are small vehicles, such as

For example, two-wheelers, tricycles, so-called tuk-tuks, snowmobiles, quads or

Scooter. In such CVT transmissions, centrifugal governors are often used to adjust a position of a belt on a cone pulley pair. Depending on the speed centrifugal weights of the shift

Centrifugal controller while their radial position, whereby an axial distance between two conical disks is changed and thereby a translation of the

Transmission is changed. A disadvantage of such arrangements, however, is that no controlled intervention in the transmission ratio of the CVT transmission is possible. This will be the CVT transmission with

Centrifugal governors in the prior art usually not operated at an optimum point, so that fuel consumption and / or emissions of

Vehicle are deteriorated. It would therefore be desirable to exploit this potential in centrifugally-controlled CVT transmissions and to obtain a possibility of fuel reduction and emission reduction. Furthermore, centrifugally controlled CVT transmissions also have no optimal design with regard to vehicle dynamics. In particular, with an acceleration of

Vehicle from a standstill and with an acceleration of the vehicle during a journey, for example, an elasticity starting from a first Speed to a second speed, there is still considerable room for improvement due to the not optimally selected transmission ratio of the centrifugal CVT transmission.

Disclosure of the invention

The CVT transmission according to the invention with the features of claim 1, on the other hand, has the advantage that an emission behavior and a

Fuel consumption of a vehicle can be significantly improved. Furthermore, also significantly better performance, especially in the

Driving dynamics with respect to an acceleration from a standstill and with respect to an acceleration of a moving vehicle reached. this will

According to the invention achieved in that the CVT transmission can be operated in each case in an optimized position. According to the invention, the CVT transmission in this case comprises a pair of conical disks with a stationary conical disk and an axially movable conical disk. Furthermore, the transmission according to the invention comprises an adjusting device for adjusting a position of the axial

movable cone pulley. The adjusting device comprises a bearing which is provided between the axially movable conical disk and a bearing bush, which is arranged on the axially movable conical disk.

As a result, co-rotation of the bearing bush with a crankshaft during operation is avoided. Furthermore, the adjusting device comprises a spindle drive with a spindle and a spindle nut and a lever which connects the spindle nut with the bearing bush. An actuator is provided to the

To drive spindle drive. A control unit is configured to operate the actuator to change a position of the axially movable cone pulley. Thus, according to the invention, an adjustment by the control unit of a CVT transmission can be made possible in order to optimize the CVT transmission

Operate operating points.

The dependent claims show preferred developments of the invention.

More preferably, an output shaft of the actuator of the adjusting device is arranged parallel to a central axis of the cone pulley pair. This allows a particularly compact design can be achieved. For a further compact construction of the transmission, the spindle of the spindle drive is preferably arranged parallel to the central axis of the conical disk pair.

More preferably, the bearing bush is provided with a recess to receive an end of the lever which connects the spindle nut with the bearing bush. The recess is preferably a groove.

Preferably, a torque arm is further provided, which is connected to the bearing bush to prevent rotation of the bearing bush together with the axially movable conical disk.

Preferably, the lever has a lever extension, which on a

Abutment is articulated by means of a joint. As a result, actuating forces are reinforced in accordance with the law of levers. The torque arm is preferably supported on an engine block.

The control unit is preferably set up to control the setting device based on parameters of a drive motor. As parameters of the

Drive motor, a speed of the drive motor and / or a torque of the drive motor and / or a temperature and / or air pressure are preferably used. The parameters for controlling the adjusting device can be detected directly on the drive motor or on with the

Drive motor connected components. The drive motor is preferably an internal combustion engine.

More preferably, the control unit is configured to control the setting device based on a choice of a driving mode of a driver. For example, predetermined transmission settings can be stored which, with appropriate selection of a driving mode, e.g. a sports mode or a fuel

Economic mode or the like. Be taken by the actuator.

More preferably, the crankshaft passes through the cone pulley pair. Thereby, a particularly compact construction of the CVT transmission and in particular the unit comprising the CVT transmission and the drive motor can be achieved. More preferably, the stationary conical disk is connected directly to the crankshaft, so that in the axial direction of the crankshaft only a minimal

Space requirements for the CVT transmission is necessary.

Furthermore, the present invention relates to a vehicle comprising a

inventive CVT transmission. The vehicle is preferably a

Small vehicle, especially a two-wheeler or a tricycle or a snowmobile or quad or a scooter or the like.

More preferably, the actuator is arranged on a housing of the CVT transmission. Preferably, an output shaft of the actuator protrudes into the housing interior and an intermediate gear for adjusting the support wall is preferably arranged in the housing interior.

drawing

Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. In the drawing is:

1 shows a schematic sectional view of a CVT transmission according to a first preferred embodiment of the invention,

Figure 2 is a perspective view of the transmission of Figure 1, and

Figure 3 is a schematic sectional view of a CVT transmission according to a second preferred embodiment of the invention.

Preferred embodiments of the invention

Hereinafter, a CVT transmission 1, that is, a continuously variable continuously variable transmission according to a first embodiment will be described in detail with reference to Figs.

As can be seen from FIG. 1, the CVT transmission 1 comprises a

Conical disk pair 2 with a fixed conical disk 20 and an axially movable conical disk 21. The fixed conical disk 20 is fixed on a crankshaft 1 1. More precisely, as can be seen from FIG. 1, the stationary conical disk 20 is arranged at the end of the crankshaft 11. The crankshaft 1 1, as indicated in Figure 1, connected to a drive motor 10, in particular an internal combustion engine.

To adjust the axially movable conical disk 21, an adjusting device 5 is provided according to the invention, which is connected to a control unit 6. The adjusting device 5 comprises an actuator 50, an output shaft 51 of the actuator and a spindle drive 3. The spindle drive 3 comprises a spindle 30 and a spindle nut 31, which is arranged axially movable on the spindle. The spindle 30 is connected to the output shaft 51 or alternatively formed integrally with the output shaft 51. Preferably, a bending moment support is arranged on the spindle nut 31 in order to increase rigidity.

The adjusting device 5 further comprises a lever 4, which connects the spindle nut 31 with a bearing bush 8, as shown in FIG. The

Bearing bush 8 is positioned on a rear wall 22 of the axially movable conical disk 21 and allows axial displacement of the axially movable

Cone pulley 21. Here, the bearing bush 8 comprises a recess 80 in the form of a groove, in which engages one end of the lever 4. Since the lever 4 is fixedly connected to the spindle nut 31, the bearing bush 8 is moved in the axial direction during an axial movement of the spindle nut 31.

Between the bearing bush 8 and the axially movable conical disk 21, a bearing assembly 7 with a first bearing 71 and a second bearing 72 is further arranged. This avoids that the bearing bush 80 in operation together with the axially movable conical disk 21 and der

Crankshaft 1 1 rotates. The axial displacement force is transmitted from the bearing bush 8 via the two bearings 71, 72 to the axially movable conical disk 21.

As can be seen from FIG. 2, a torque arm 81 is provided, which is connected to the bearing bush 8 in order to prevent a rotation of the bearing bush 8 together with the axially movable conical disk 21. The actuator 50 is preferably an electric motor. Alternatively, however, the adjusting device 5 comprises a pneumatically operated adjustment drive or a hydraulically operated Versteilantrieb or an electromagnetic Versteilantrieb.

A wrapping means 12, e.g. a belt is between the two

Cone disks 20, 21 arranged. The belt 12 is connected to an output element 13, preferably also a cone pulley pair. The output element 13 may, for example, also be a directly driven wheel or the like.

According to the invention can thus be adjusted via the control unit 6, a position of the movable conical disk 21 and thereby an axial distance between the two conical disks 20, 21 are set, which provides a desired ratio of the CVT transmission. For this purpose, the

Actuator 50 is driven and the spindle drive 3 converts the rotation into an axial movement of the spindle nut 31. Since the lever 4 is rigid with the

Spindle nut 31 is connected, according to the lever 4, as indicated in Figure 1 by the double arrow A, moved in the axial direction X-X. As a result, the bearing bush 8, and the axially movable conical disk 21 is axially displaced via the bearing assembly 7. As a result, the belt, depending on the direction of rotation of the actuator 50 on the circumference of the

Cone pulleys further outwards or further inwards. Thus, a stepless transmission can be realized.

Furthermore, the use of centrifugal elements, as in the prior art, can be dispensed with. This results in a less expensive and simpler and reliable construction. According to the invention, depending on parameters, such as

Speed and / or the torque of the drive motor 10 and / or a temperature and / or an air pressure, an optimized gear ratio can be realized. The gear ratio can in terms of a

Consumption optimization or emission optimization or optimization of acceleration of the vehicle to be selected. Also, any

Combined to be optimized output variables and In accordance with this optimum transmission ratio of the CVT transmission can be adjusted.

Experiments with a CVT transmission 1 according to the invention have shown that a consumption saving of fuel in the range of 10% is possible, an improved acceleration in a range between 0 to 60 km / h of up to 17% is possible and improved elasticity of Acceleration in a range between 20 to 50 km / h of 19% compared to a normal centrifugal CVT transmission are possible. Although the CVT transmission according to the invention requires a slightly larger mechanical and electrical structure by the adjusting device, this can be more than made up for by the improvements and savings described. Figure 3 shows a CVT transmission 1 according to a second embodiment of the

Invention, wherein the same or functionally identical parts with the same

Reference numerals are designated. In contrast to the first embodiment, a lever extension 40 is additionally provided in the second embodiment. The lever extension 40 is connected via a hinge 41 at a

Abutment 42 hinged. As a result, the lever 4 is articulated, so that increase actuating forces of the spindle drive 3 in accordance with the law of levers. This allows a smaller design of the actuator 50 are made possible and the entire structure of the transmission can be realized cheaper and more compact.

Claims

CVT transmission, comprising:

a conical disk pair (2) with a stationary conical disk (20) and an axially movable conical disk (21),

an adjusting device (5) for adjusting a position of the axially movable conical disk (21),

wherein the adjusting device (5) comprises:

a bearing bush (8), which on the axially movable

Cone pulley (21) is arranged

a bearing arrangement (7) which is arranged between the axially movable conical disk (21) and the bearing bush (8), a spindle drive (3) with a spindle (30) and a

Spindle nut (31),

a lever (4), which the spindle nut (31) with the

Bearing bush (8) connects, and

an actuator (50) for driving the spindle drive (3), and a control unit (6) arranged to operate the actuator (5) to change the position of the axially movable conical disk (21).

Transmission according to claim 1, characterized in that a

Output shaft (51) of the actuator (50) is parallel to a central axis (X-X) of the conical disk pair (2).

Transmission according to one of the preceding claims, characterized

characterized in that the spindle (30) of the spindle drive (3) is parallel to the central axis (X-X) of the cone pulley pair (2).

Transmission according to one of the preceding claims, characterized

characterized in that the bearing bush (8) comprises a recess (80), in particular a groove, for receiving one end of the lever (4). Transmission according to one of the preceding claims, further comprising a torque arm (81) which is connected for support with the bearing bush (8) in order to prevent rotation of the bearing bush together with the axially movable conical disk (21).

Transmission according to one of the preceding claims, characterized

characterized in that the lever (4) comprises a lever extension (40), wherein the lever extension (40) is articulated on an abutment (42) by means of a hinge (41).

Transmission according to one of the preceding claims, characterized

in that the control unit (6) is set up

Actuating device (5) based on characteristics of a drive motor (10), in particular a rotational speed and / or a torque of

Drive motor and / or a temperature and / or air pressure to control.

Transmission according to one of the preceding claims, characterized

in that the control unit (6) is set up

Control device (5) to control based on a choice of a driving mode by the driver.

Transmission according to one of the preceding claims, characterized

characterized in that the crankshaft (1 1) through the cone pulley pair (2).

Transmission according to one of the preceding claims, characterized

characterized in that the stationary conical disk (20) directly to the crankshaft (1 1), in particular at one end of the crankshaft (1 1), is connected.

Vehicle comprising a transmission according to one of the preceding claims.

Vehicle according to claim 1 1, characterized in that the vehicle is a small vehicle, in particular a two-wheeler or a tricycle or a snowmobile or a quad or the like., Is.