DE102015225029A1 - CVT - Google Patents

Abstract

It is a continuously variable transmission (10) for substantially continuously varying a transmission ratio in a drive train of a motor vehicle provided with an input cone pulley pair (12), wherein the Eingangskegelscheibenpaar (12) an input counter-disc (18) and a relative to the input counter-disc (18) axially displaceable Eingangsverstellscheibe ( 20), a Ausgangskegelscheibenpaar (14), wherein the Ausgangskegelscheibenpaar (14) has a Ausgangsgegenscheibe (28) and a relative to the counterpart disc (28) axially displaceable Ausgangsverstellscheibe (30), and the input cone pulley pair (12) with the output cone pulley pair (14) coupling Umschlingungsmittel (16), wherein the input counter-disc (18) with the Eingangsverstellscheibe (20) via at least one input sheet spring (44) for pressing the Umschlingungsmittels (16) and / or the output counter-disc (28) with the Ausgangsverstellscheibe (30) via at least one output sheet spring (32) for pressing the belt (16) is connected. With the help of the input leaf spring (44) and / or the output leaf spring (32) internal friction can be easily avoided, so that an alternative continuously variable transmission (10) with a simple and robust construction and high efficiency is possible.

Description

The invention relates to a continuously variable transmission, with the help of which in a drive train of a motor vehicle, a torque and a speed can be continuously changed.

For example DE 2 104 546 A1 is a continuously variable transmission with two coupled via a V-belt conical disk pairs known, the conical disks of conical disk pairs can be displaced in the axial direction against each other so that the V-belt can act on a changing radius of the respective cone pulley pair, whereby the transmission ratio can be changed continuously. The conical disks of the respective cone pulley pair are biased towards each other by means of a helical spring, so that the conical disks can rest against the belt with a sufficient frictional force. At the input side conical disk pair a speed sensor with centrifugal masses is provided, which exerts a centrifugal force-increasing contact pressure on the belt at an increasing speed and thereby displaces the V-belt at a rising input speed to a larger radius, whereby the translation as a function of the attacking speed Automatically change continuously.

There is a constant need for alternative continuously variable transmissions, which are particularly simple and robust and have a high efficiency.

It is the object of the invention to show measures that allow an alternative continuously variable transmission, which is particularly simple and robust and has a high efficiency.

The object is achieved by a continuously variable transmission with the features of claim 1. Preferred embodiments of the invention are set forth in the dependent claims and the description below, which may each individually or in combination constitute an aspect of the invention.

According to the invention, a continuously variable transmission for essentially continuously varying a transmission ratio in a drive train of a motor vehicle is provided with an input cone pulley pair for introducing a torque, wherein the input cone pulley pair has an input counter-pulley and an input shift pulley axially displaceable relative to the input counter-pulley, an output conical pulley pair for discharging the torque, wherein the output conical pulley pair an input counter-plate and a relative to the output counter-plate axially displaceable Ausgangsverstellscheibe, and the input cone pulley pair with the Ausgangskegelscheibenpaar coupling Umschlingungsmittel, in particular V-belt, the input counter-disc with the Eingangsverstellscheibe via at least one input leaf spring for pressing the belt and / or the original counter-plate with the Ausgangverstellscheibe via at least one Ausgangsbla Ttfeder is connected to press the belt.

The continuously variable transmission, also referred to as continuously variable transmission (CVT) transmission, by changing the axial distance of the Eingangsverstellscheibe to the input counter-disc and a corresponding change in the axial distance of Ausgangsverstellscheibe to the original counter-gear ratio, and thus the transmitted torque and continuously 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 cone pulley pairs on the belt means. With the help of the input leaf spring and / or the output leaf spring, the corresponding adjusting disc can be pressed or pulled onto the associated counter-disk of the respective cone pulley pair, so that the input cone pulley pair and / or the output conical disk pair can rest against the belting means with the aid of the associated leaf spring with a sufficient contact force to transmit a desired torque. If a leaf spring is provided only for the input cone pulley pair or only for the output cone pulley pair, the contact pressure function can also be achieved by a helical spring or another spring element.

Unlike a coil spring, however, the leaf spring, that is, the input leaf spring and / or the output leaf spring, need not be plugged on a mandrel to prevent kinking. This makes it possible for the leaf spring to avoid a frictional relative movement or at least reduce. A friction of adjacent turns can not occur in the leaf spring. Due to the lower internal friction losses, the continuously variable transmission can have a correspondingly higher efficiency. The leaf spring may include a plurality of layered leaf spring elements that can withstand higher loads compared to a multi-turn coiled wire of a coil spring. Due to the stable leaf spring, the continuously variable transmission can be more robust and fail-safe. In addition, the leaf spring can be easily and inexpensively produced by punching from a metal sheet become. The leaf spring can be connected to the adjusting disk at one axial end and to the counter disk of the respective conical disk pair, for example by riveting, with the opposite axial end. This results with the help of the leaf spring, a simple and robust realization of a contact pressure for the corresponding cone pulley pair. With the help of the input leaf spring and / or the output leaf spring can be easily avoided internal friction, so that an alternative continuously variable transmission is made possible with a simple and robust construction and high efficiency.

In particular, more than one leaf spring, for example two or three leaf springs, is provided for the input cone pulley pair and / or for the output cone pulley pair. By means of the plurality of leaf springs, it is easy to set a suitable spring characteristic for the relative axial movement of the respective adjusting disk relative to the associated counter-disk of the respective conical disk pair. The spring characteristic may be linear but also non-linear, for example, with sections of different spring constants, be designed. In the train operation of the motor vehicle, that is, when a torque to be transmitted to a drive wheel of an automotive engine, the torque is introduced at the input cone pulley pair and discharged at the output cone pulley pair.

For this purpose, the input cone pulley pair can optionally be coupled via a separating clutch to a drive shaft of the motor vehicle engine. The output cone pulley pair may be coupled to an output shaft coupled to a drive wheel. The continuously variable transmission can be used, in particular, as an automatic motor vehicle transmission for two-wheeled vehicles, for example scooters, smaller four-wheelers, for example quad-bikes, or snowmobiles, which usually require a lower power spread compared to passenger cars.

In particular, it is provided that the at least one input leaf spring, in particular at least two or three input leaf spring, the Eingangsverstellscheibe axially centered relative to the input counter-disc and / or the at least one output leaf spring, in particular at least two or three output leaf spring, the Ausgangsverstellscheibe axially relative to the outer counter-disc. Preferably, the centering of the adjusting disk to the counter-disk is effected exclusively via the associated leaf spring. In particular, three leaf springs are provided, which are offset in the circumferential direction by 120 ° to each other. A power flow between the adjusting and the counter pulley is carried out in particular exclusively on the at least one leaf spring and the belt. A storage of the adjusting disc on the opposite disc, especially for the purpose of centering, can be saved. Power losses of the continuously variable transmission by a storage of the adjusting disc on the counter-plate are thereby avoided. The centering of the adjusting disk on the counter disk can thus take place with the aid of the at least one leaf spring substantially without friction. In particular, a guidance of the adjusting disk on the counter disk can be avoided by means of a bolt guided in a milled groove, whereby manufacturing costs can be saved.

Preferably, the Eingangsverstellscheibe to the input counter-plate and / or the Ausgangsverstellscheibe to the output counter-plate is relatively limited rotatable. A non-rotatable and thus frictional coupling of the adjusting disc with the counter-disk can be saved. Slippage of a cone pulley, that is adjusting or counter-pulley, while the other conical disk, that is counter-pulley or adjusting, with the belt means rotates can be avoided by the leaf spring. Since the leaf spring can also transmit a torque, the end of the leaf spring fixed with the co-rotating conical disk can take along the end of the leaf spring attached to the slipping conical disk and thereby also entrain the previously slipping conical disk. Uneven engagement conditions in the respective cone pulley pair can be avoided by the associated leaf spring.

Particularly preferably, the input leaf spring and / or the output leaf spring extends at least with a proportion in the tangential direction. In a relative rotation of the adjusting disc to the counter-disc, the leaf spring can be taken from the overhauling conical disk. This allows the leaf spring to simultaneously pull the outdated conical disk. Due to the at least partially tangential orientation of the leaf spring, the leaf spring can exert a share of force in the axial direction on the pulled-over obsolete conical disk. When the leaf spring is loaded with tension, the leaf spring can pull the pulled over obsolete conical disk onto the overhauling conical disk so that the axial distance between the adjusting disk and the counter disk is reduced. This increases the contact pressure of the conical disks on the belt, whereby a sufficient frictional connection can be established both between the adjusting disk and the belt and between the counter pulley and the belt. This allows a sufficient torque transmission between the conical disk pair and the belt be ensured and a relative rotation of the adjusting be turned off to the opposite disc. The leaf spring can thereby provide a self-reinforcing adhesion between the belt and the cone pulley pair even at very high torques. The leaf spring can thereby act not only as a contact pressure for providing a contact force of the conical disk pair on the belt, but also as a torque sensor for adjusting the contact pressure on an applied torque.

In particular, the input leaf spring is loaded in a torque transmission between the input counter-plate and the input shift pulley in the train operation and / or the output leaf spring at a torque transmission between the output counter-plate and the Ausgangsverstellscheibe in train operation to train. As a result, buckling of the leaf spring under load can be avoided. In this case, it can be considered in particular which conical disk is more strongly driven or driven than the other associated conical disk. For example, in the case of the pair of input cone pulleys, either the counter-disk or the adjusting disk can be coupled to the drive shaft of the motor vehicle transmission, so that the conical disk coupled to the drive shaft is more likely to overtake the other conical disk during traction, in which case the input leaf spring is loaded in tension. Correspondingly, for example, in the output cone pulley pair, either the counter-disk or the adjusting disk can be coupled to the drive wheel, so that due to the resistance torque of the drive wheel, the conical disk coupled to the drive wheel tends to be overtaken by the other conical disk in traction mode, in which case the output leaf spring is loaded on train. As a result, in particular, the respective leaf spring automatically bring about an increase in the contact force of the cone pulley pair on the belting means in an overhauling conical disk by the leaf spring loaded on train pulls the adjusting disk and the counter disk towards each other.

Preferably, the input leaf spring has a different spring characteristic from the output leaf spring. Thereby, the course of the transmission ratio of the continuously variable transmission in dependence on the introduced power, in particular the rotational speed and / or the torque can be suitably adjusted. Depending on the torque introduced, a balance between the provided by the input leaf spring and the output leaf spring spring force can be adjusted, which in turn is associated with a specific gear ratio.

Particularly preferably, the input leaf spring is radially inwardly to the radially innermost layer of the belt in the pair of input cone and / or the output leaf spring radially inwardly to the radially innermost layer of the belt in the Ausgangskegelscheibenpaar attached. The respective leaf spring can not thereby collide with the belt. In addition, space can be used for the leaf spring, which is not used anyway by the belt, so that the space of the continuously variable transmission can be kept low.

In particular, the input cone pulley pair and / or the output cone pulley pair has a rotational speed sensor for the centrifugal force-related increase of a contact pressure force for pressing the belting means. The speed sensor may, for example, have a centrifugal mass that can be moved radially outward under the influence of centrifugal force. The centrifugal mass can attack, for example, at a ramp coupled to the adjusting disk or the counter disk, whereby the axial distance between the adjusting disk and the counter disk of the input cone disk pair or of the output cone disk pair can decrease at an increasing rotational speed and an increasing centrifugal force on the centrifugal mass. This simultaneously increases the contact pressure of the respective conical disk pair on the belt. In particular, with the aid of the speed sensor at an increasing speed, the belt can be displaced to a larger diameter of the associated cone pulley pair, whereby the transmission ratio can be changed automatically as a function of the attacking speed. Since by the at least one leaf spring, preferably three leaf springs, a centering and / or guiding the adjusting disc can be realized on the opposite disc, otherwise provided for this purpose components can be saved. This leads to a lower inertial mass of the conical disk to be displaced by the speed sensor, so that a centrifugal mass with a correspondingly lower inertial mass can already be sufficient. The centrifugal mass can thereby be made smaller, for example, so that manufacturing costs and space for the speed sensor can be saved.

Preferably, the output cone pulley pair is connected via a centrifugal clutch with a bell for driving a drive wheel. At a low speed, in particular standstill, the continuously variable transmission can thereby be separated automatically from the drive wheel and provided by the drive wheel drag torque. A coupling with the drive wheel can take place only when the speed and the Provided line is large enough to overcome the downstream drag torque and move the motor vehicle. A stalling of the motor vehicle engine can be avoided.

Particularly preferably, the input counter-plate or the Eingangsverstellscheibe rotationally fixed to a drive hub, in particular a drive shaft of a motor vehicle engine, connected. For example, the drive shaft is rotatably coupled directly or indirectly via a separating clutch with one of the conical disks of the input cone pulley pair. As a result, the drive power of the motor vehicle engine can be introduced into the continuously variable transmission without significant power losses.

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 sectional view of a first embodiment of a continuously variable transmission and

2 : A schematic sectional view of a second embodiment of a continuously variable transmission.

This in 1 illustrated continuously variable transmission 10 has an input cone pulley pair 12 and an output cone pulley pair 14 on, via a designed as a V belt straps 16 coupled together. The input cone pulley pair 12 has an input counter-disc rotatably coupled to a drive shaft of an automotive engine 18 on, in the illustrated embodiment, a Eingangsverstellscheibe 20 rotatably but axially slidably connected. The input adjusting disc 20 has a ramp 22 on, due to the centrifugal force a spherical centrifugal mass 24 a speed sensor 26 can attack. If the input counter-disc 18 is driven by the motor vehicle engine and, for example via a spline the Eingangsverstellscheibe 20 takes along, is also the speed sensor 26 rotated, so that the centrifugal mass 24 Due to centrifugal force can be moved radially outward. The centrifugal mass 24 can against the ramp 22 Press and thereby the Eingangsverstellscheibe 20 on the entrance counter-pane 18 to move. As a result, the contact pressure of the input counter-disk 18 and the Eingangsverstellscheibe 20 on the belt 16 be increased and finally the belt 16 to a larger effective radius of the input cone pulley pair 12 be shifted, which is dependent on the on the input cone pulley pair 12 acting speed, the gear ratio of the continuously variable transmission 10 can change. Optionally, a spring element on the input counter-disc 18 and the Eingangsverstellscheibe 20 attack, even at a low speed, a contact pressure of the input cone pulley pair 12 be able to provide on the belt means.

The output cone pulley pair 14 has a starting counter-disc 28 and one relative to the original counter-disk 28 axially displaceable Ausgangsverstellscheibe 30 on. With the original counter-pane 28 and the Ausgangsverstellscheibe 30 is radially inward to the illustrated maximum far radially inner relative position of the belt 30 within the output cone pulley pair 14 an output leaf spring 32 riveted. The output leaf spring 32 can the original counter-disc 28 and the Ausgangsverstellscheibe 30 to pull each other and thereby a contact force of the output cone pulley pair 14 on the belt 16 impress. In particular, there are two, three or more output leaf springs 32 provided so that the Ausgangsverstellscheibe 30 from the output leaf springs 32 at the exit counter-pane 28 can be additionally centered. The output adjusting disc 30 can in this case without direct frictional contact, for example, with clearance, on the original counter-pane 28 be centered.

With the original counter-pane 28 is a centrifugal clutch 34 connected, which above a limit speed a frictional engagement with a bell 36 manufactures. The bell 36 is non-rotatable with an output shaft 38 connected, which can drive a drive wheel of the motor vehicle. In the illustrated embodiment, the output shaft 38 about a first camp 40 and a second camp 42 essentially non-tilting on the original counter-plate 28 of the output cone pulley pair 14 stored.

At the in 2 illustrated embodiment of the continuously variable transmission 10 is compared to the in 1 illustrated embodiment of the continuously variable transmission 10 also the input counter-pane 18 and the input disc 20 via an input leaf spring 44 connected to each other, so that instead of a rotationally fixed splines between the input counter-disc 18 and the Eingangsverstellscheibe 20 a game can be provided. The input adjusting disc 20 Can have two, three or more input leaf springs 44 without frictional contact with radial play on the input counter-disc 18 be centered. The input leaf spring 44 can the input counter-disc 18 and the input disc 20 pull each other so that, if necessary, the inertial mass and the volume of the centrifugal mass 24 of the speed sensor 26 can be reduced.

LIST OF REFERENCE NUMBERS

10

 CVT

12

 Input conical pulley

14

 Output conical pulley

16

 endless

18

 Input counter disc

20

 Eingangsverstellscheibe

22

 ramp

24

 centrifugal mass

26

 Speed sensor

28

 Output counter disc

30

 Ausgangsverstellscheibe

32

 Output leaf spring

34

 centrifugal clutch

36

 Bell jar

38

 output shaft

40

 first camp

42

 second camp

44

 Input leaf spring

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 2104546 A1 [0002]

Claims (10)

Continuously variable transmission for substantially continuously varying a transmission ratio in a drive train of a motor vehicle, with an input cone pulley pair ( 12 ) for introducing a torque, wherein the input cone pulley pair ( 12 ) an input counterpart disc ( 18 ) and one relative to the input counter-disk ( 18 ) axially displaceable input adjusting disc ( 20 ), a Ausgangskegelscheibenpaar ( 14 ) for deriving the torque, where in the output cone pulley pair ( 14 ) a starting counter-disk ( 28 ) and one relative to the original counterpart disc ( 28 ) axially displaceable output adjusting disc ( 30 ) and the input cone pulley pair ( 12 ) with the output cone washers ( 14 ) coupling means ( 16 ), in particular V-belts, wherein the input counter-disk ( 18 ) with the input adjusting disk ( 20 ) via at least one input leaf spring ( 44 ) for pressing the belt ( 16 ) and / or the original counterpart disc ( 28 ) with the Ausgangsverstellscheibe ( 30 ) via at least one output leaf spring ( 32 ) for pressing the belt ( 16 ) connected is. Continuously variable transmission according to claim 1, characterized in that the at least one input leaf spring ( 44 ), in particular at least two or three input leaf spring ( 44 ), the input disk ( 20 ) relative to the input counter-disk ( 18 ) axially centered and / or the at least one output leaf spring ( 44 ), in particular at least two or three output leaf spring ( 44 ), the Ausgangsverstellscheibe ( 30 ) relative to the original counter-disk ( 28 ) axially centered. Continuously variable transmission according to claim 1 or 2, characterized in that the Eingangsverstellscheibe ( 20 ) to the input counter-disk ( 18 ) and / or the Ausgangsverstellscheibe ( 30 ) to the original counterpart disc ( 28 ) is relatively limited rotatable. Continuously variable transmission according to one of claims 1 to 3, characterized in that the input leaf spring ( 44 ) and / or the output leaf spring ( 32 ) runs at least with a proportion in the tangential direction. Continuously variable transmission according to one of claims 1 to 4, characterized in that the input leaf spring ( 44 ) in a torque transmission between the input counter-plate ( 18 ) and the input disk ( 20 ) in train operation and / or the output leaf spring ( 32 ) at a torque transmission between the original counter-disc ( 30 ) and the Ausgangsverstellscheibe ( 28 ) is loaded in train operation on train. Continuously variable transmission according to one of claims 1 to 5, characterized in that the input leaf spring ( 44 ) one of the output leaf spring ( 32 ) has different spring characteristic. Continuously variable transmission according to one of claims 1 to 6, characterized in that the input leaf spring ( 44 ) radially inward to the radially innermost layer of the belt ( 16 ) in the input cone pulley pair ( 12 ) and / or the output leaf spring ( 32 ) radially inward to the radially innermost layer of the belt ( 16 ) in the output cone pulley pair ( 14 ) is attached. Continuously variable transmission according to one of claims 1 to 7, characterized in that the input cone pulley pair ( 12 ) and / or the output cone pulley pair ( 14 ) a speed sensor ( 26 ) for the centrifugal force-induced increase of a contact pressure for pressing the belt ( 16 ) having. Continuously variable transmission according to one of claims 1 to 8, characterized in that the output cone pulley pair ( 14 ) via a centrifugal clutch ( 34 ) with a bell ( 36 ) is connected to drive a drive wheel. Continuously variable transmission according to one of claims 1 to 9, characterized in that the input counter-disk ( 18 ) or the input adjusting disk ( 20 ) rotatably connected to a drive hub, in particular a drive shaft of a motor vehicle engine, is connected.

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