EP1966523A1

EP1966523A1 - Method for improving the suitability for towing of a vehicle which is equipped with a cone pulley transmission, and cone pulley pair

Info

Publication number: EP1966523A1
Application number: EP06828618A
Authority: EP
Inventors: Hartmut Faust
Original assignee: LuK Lamellen und Kupplungsbau Beteiligungs KG; LuK Lamellen und Kupplungsbau GmbH
Current assignee: Schaeffler Buehl Verwaltungs GmbH; LuK Lamellen und Kupplungsbau GmbH
Priority date: 2005-12-21
Filing date: 2006-12-06
Publication date: 2008-09-10
Also published as: JP2009520923A; DE112006003203A5; WO2007071227A1

Abstract

A cone pulley pair for a cone pulley transmission comprises an input shaft which is connected rigidly to a fixed disc, a moving disc which is arranged fixedly in terms of rotation and axially displaceably on the shaft, an input component which can be driven by a drive motor, a torque sensing device having a first component which is in torque-transmitting engagement with the input component and has first shaped surfaces, and having a second component which is in torque-transmitting engagement with the moving disc and has second shaped surfaces, and rolling bodies which are arranged between the shaped surfaces, which shaped surfaces are configured in such a way that, as the torque which acts between the shaped surfaces increases, the shaped surfaces are moved away from one another counter to a force which pushes the shaped surfaces towards one another, with rolling of the rolling bodies which are arranged between them, the shaped surfaces being configured in such a way that, in the case of a low or absent force which pushes them towards one another, they are moved away from one another in such a way that the rolling bodies run over the shaped surfaces and the torque transmission between the first component and the second component is interrupted.

Description

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- 1 -

Method for improving the towing of a vehicle equipped with a key disk drive and conical disk pair

The invention relates to a method for improving the towing ability of a vehicle equipped with a conical-pulley transmission. The invention further relates to a conical disk pair for a conical-pulley transmission.

Cone pulley, as used for example in motor vehicles, generally contain two conical disk pairs, which are wrapped by a belt, for example a link chain. By opposing change in the distance between the conical disks of each conical disk pair, the transmission ratio can be changed continuously.

A problem of motor vehicles equipped with such a belt pulley is that, in the event of failure of the vehicle's drive motor, towing is possible only within narrowly defined conditions so that there is no damage, in particular due to a lack of oil pressure or hydraulic pressure supply. When towing with a stationary motor and thus non-driven pump to provide hydraulic pressure, almost all of the drive train is driven from the wheels ago up to a starting clutch or a converter in conventional conical-pulley. Due to poor lubrication gear damage, especially on clutches, planetary gear sets (usually as reversible sets for reversing), bearings, etc. occur when the strict requirements for maximum travel speed and maximum travel distance are not met.

The invention has for its object to reduce the towing problems that exist when towing equipped with a conical-pulley transmission vehicles.

A first solution of this object is achieved with a method for improving the towing ability of a vehicle equipped with a conical-pulley transmission, in which method torque-transmitting engagement between the bevel-belt transmission and the drive motor of the vehicle is provided by the vehicle the torque acting on the conical pulley and the lack of hydraulic pressure on the conical pulley is interrupted.

Advantageously, the torque-transmitting engagement by hydraulic pressure of the conical-pulley belt transmission can be restored.

Another solution of the invention task is achieved with a pair of conical pulleys for a conical pulley, which cone pulley pair includes an input shaft which is rigidly connected to a fixed disk, a axially displaceable on the shaft and non-rotatably mounted travel disc, a drivable by a drive motor input member, a torque sensing device a first component having first shaping surfaces and a second component having second molding surfaces communicating with the rotary disk in torque transmitting engagement and rolling elements arranged between the molding surfaces are configured such that with increasing torque acting between the molding surfaces The mold surfaces, while rolling the rolling bodies arranged between them, are moved away from one another against a force urging one another against the mold surfaces, wherein the mold surfaces are designed in this way in that, with a small or missing force which is to be urged toward one another, they move away from one another such that the rolling elements overflow the shaping surfaces and the torque transmission between the first component and the second component is interrupted.

The cone pulley pair according to the invention can be designed such that the torque transmission can only be interrupted when the torque acting on the travel disc is present.

Advantageously, the first component is a rotatably connected with an input shaft mounted on the input shaft ring member, at its applied from the input end face, the first molding surfaces are formed, and the second component is an input shaft encompassing, relative to the input shaft axially displaceable piston between the and the distance disc is arranged a pressure chamber into which a pressure source from the source of pressure acted upon inlet channel and from which a drain passage, wherein the effective cross section of an inlet and / or drain opening is changed by the axial position of the sensing piston.

The rolling elements are preferably designed as held in a cage balls. The molding surfaces can transition radially outward into ramps formed without ramps and the balls be radially movable, so that the balls run as a result of centrifugal force in the absence of hydraulic pressure and high speeds on largely flat tracks.

The balls may be axially biased toward pockets formed in the first or second forming surfaces to avoid constantly running against ramps of the forming surfaces when torque transmission is disengaged.

The invention is explained below with reference to schematic drawings, for example, and with further details.

In the figures represent:

FIG. 1 shows a cross section through a pair of conical disks of a conical-disk transmission,

FIG. 2 shows a section of FIG. 1,

FIG. 3 shows a detail of unrolled forming surfaces, at their maximum mutual approach, and FIG. 4 shows a view similar to FIG. 3 in relative rotation relative to FIG

View of Figure 3 slightly spaced mold surfaces.

A belt pulley, on which the invention is exemplified below, is described in terms of its basic structure in the article "multitronik - The new Audi automatic transmission", on page 548 and following the ATZ Automobiltechnische Zeitschrift 102 (2000) 7/8.

According to FIG. 1, a pair of conical disks of such a conical-pulley belt drive has an input shaft 10, which is formed integrally with a fixed disk 12. On the shaft 10 is axially displaceable, but rotatably connected to the shaft of the fixed disk opposite a washer 14 is arranged. An unillustrated belt circulates between the conical surfaces of the discs and the conical surfaces of another pair of cones (not shown). - A -

In the position shown in FIG. 1, in which the travel plate 14 is largely moved to the left according to the figure, there is an annular flange 16 of the travel disc, via which the axially displaceable but non-rotatable guidance of the travel plate 14 takes place on the input shaft 10 his left front end to a rigidly connected to the shaft 10 support ring 18, which ends in its radially outer region in an open towards the washer 14 annular chamber in which a rigidly connected to the washer 14 piston 20 is axially displaceable under seal. Between the piston 20 and the support ring 18, an adjustment chamber 22 is formed, which is connected via a trained in the shaft 10 and an axial passage 24 via a radial bore of the shaft 10 and a circumferential groove with the Axiaikanal 24 and passing through the support ring 18 leading supply line 26 is. The adjustment chamber 22 is connected to hydraulic pressure for adjusting the transmission ratio or the distance between the travel plate 14 and the fixed disk 12.

On the side facing away from the windscreen 14 side of the support ring 14, a sensing piston 28 is disposed axially displaceably on the shaft 10, which is axially displaceable and rotatably connected to the support ring 18. The sensing piston 28 and the support ring 18 are formed on their mutually facing sides such that a radially inner pressure chamber 30 and a radially outer pressure chamber 32 are formed between it, the volume of which changes with an axial displacement of the sensing piston 28.

On its rear side facing away from the path plate 14 of the sensing piston 28 is formed with a circumferential, generally annular molding surface 34, which is arranged opposite another mold surface 35 of a ring member 36. Between the forming surfaces 34 and 35, rolling elements designed as balls 37 are accommodated in the illustrated example, which are held by a cage 38. The balls 37 together with the forming surfaces 34 and 35, a torque sensor, the upper half is circled in Figure 1. The ring member 36 is rigid or connected via a toothing with an input gear 40 which is mounted by means of a bearing 42 on the shaft 10 axially immovable. The ring member 36 has an outer toothing 44, via which it is rotatably driven by a drive motor, not shown.

The radially inner pressure chamber 30 is connected via radial bores with an axial channel 46 of the shaft 10, which axial channel 46 can be acted upon by a hydraulic pump forth with hydraulic pressure. Further, the pressure chamber 30 is connected via radial drain holes 48 with a drain channel 50. The radially inner pressure chamber 30 is not shown Passages connected to a pressure chamber 52 which is formed between the support ring 18 and the spacer plate 14 radially within the adjustment chamber 22. The pressure chamber 52 is connected via passages of the path plate 14 with a formed between the washer 14 and the shaft 10 annular chamber 54. The radially outer pressure chamber 32 is connected via radial passages, which pass through the support ring 18 and the shaft, with a further axial channel 56 of the shaft, of which in the illustrated position of the spacer plate 14 not covered by the spacer disk radial passages 58 in the space between the Cone pulleys 14 and 12 lead.

The function of the cone pulley pair described so far is known per se and is therefore explained only briefly:

In Figure 1, the position of the cone pulley pair with the greatest possible distance between the letters 12 and 14 is shown. Assuming that the axial passage 46 is pressurized with hydraulic pressure acting in the radially inner pressure chamber 30 and urging the sensing piston 28 to the left in the figure. When the input gear 40 is driven by a drive motor, torque is transmitted to the forming surface 34 of the sensing piston 28 from the forming surface 35 non-rotatably connected to the input gear via the balls 37, resulting in the sensing piston 28 being deformed by the balls 37 move along ramps at least one of the molding surfaces 34 and 35, the distance between the molding surfaces increases and the sensing piston moves according to Figure 1 to the right. In this case, the sensing piston increasingly closes the drain hole 48 opening into the drainage channel 50, whereby the pressure in the radially inner pressure chamber 30 increases, so that the contact force with which the spacer plate 14 is urged in the direction of the fixed disk 12 increases and overall the effective torque is proportional. If the travel plate 14 is displaced to the right in particular by acting on the adjustment chamber 22 with hydraulic pressure, the annular chamber 54 connected to the pressure chamber 52 comes into overlap with the radial passage 58, whereby the radially outer pressure chamber 32 is pressurized, so that to move the sensing piston 28 increases torque required to the right. The torque sensor formed by the forming surfaces and the balls thus has a translation-dependent gradation.

In conventional conical-pulley belt transmissions, the relative rotatability between the forming surfaces 34 and 35 is limited by an axial stop of the sensing piston 28 and / or bumps formed at the ends of ramps of the forming surfaces, so that no rolling element or ball can overrun a ramp and enter the pocket of the next ramp. This results in that in trailed gear, ie in particular when the drive motor and thus lack of hydraulic supply due to the lack of hydraulic pressure according to the figure 1 rightmost moving sensing piston with interposition of the balls 37, the input gear 40 and the downstream of the startup components, such as Clutches, planetary gear sets etc. rotatably drives, whereby the above-mentioned restrictions are given in terms of towing the vehicle.

According to the invention, the torque sensor is therefore designed such that it interrupts the torque flow at insufficient hydraulic pressure in the radially inner pressure chamber 30 and two pressure chambers 30 and 32, so that no torque transmission from the washer 14 to the input gear 40 takes place.

FIG. 2 shows an enlarged detail of FIG. 1 with the torque sensor.

FIG. 3 shows a development of the shaping surfaces in the height of the plane III-III of FIG. 2 in the absence of torque. FIG. 4 shows the view of FIG. 3 with the torque present.

In Figure 2 is clearly visible how the balls 37 are held by a cage 38 between the mold surfaces 34 and 35, wherein the cage 38 is supported via a lateral projection on the outer edge of the ring member 36.

In Figure 3, the opposing mold surfaces 34 and 35 are shown unwound, with no torque between the sensing piston 28 and the annular member 36 is present, so that the mold surfaces approach each other maximum and the balls 37 in the opposite recesses or pockets each mold surface are held. The distance between the balls is predetermined by the cage 38.

If, according to FIG. 4, a torque directed to the left according to the arrow is exerted on the sensing piston 28 during towing of the vehicle, this causes the sensing piston 28 to rotate relative to the ring component 36 in the direction of the arrow (in the illustrated state about that in the circumferential direction measured distance s), whereby the ramps of the forming surface 34 move relative to the balls 37. In the illustrated state, the molding surface 34 has moved relative to the molding surface 35 about a distance s measured in the circumferential direction, whereby the components 28 and 36 have separated by the distance h - hi. If the distance that the sensing piston 28 can move away from the ring member 36 is greater than the height h (height of a ramp), the forming surface 34 may rotate relative to the forming surface 36 without torque transmission because the ramp crests are adjacent to the Balls can move past. In this way, the torque transmission is interrupted when towing.

When the torque from the ring member 36 acts ago, the mold surface 35 moves in the opposite direction to the arrow of Figure 4. Because of the symmetrical design of the molding surfaces in this case too low contact pressure of the sensing piston 28 in the direction of the ring member 36, the interruption of torque transmission is possible, so that the conical disk belt drive is protected against excessive wear of the belt wrap along the conical surfaces at too low contact pressure.

By asymmetric design of the molding surfaces with respect to the circumferential direction, the type of torque interruption may be different when towed or driven vehicle. The mold surfaces can be designed, for example, by integrating a freewheel device such that a torque interruption takes place only when the vehicle is towed and is prevented when the vehicle is driven.

Once sufficient hydraulic pressure is present, the normal torque transfer function between the ring member 36 and the sensing piston 28 resumes.

To avoid a recurring Aufschiagens the passing past a ramp vertex balls on a subsequent ramp, the balls in the cage 38 can be radially freely driven such that they move away by centrifugal radially outward ramp areas of the molding surfaces on more outer raceways or tracks move along which they run on predominantly flat treads.

Alternatively, the cage 38 can be drawn axially on one side, for example by additional spring elements, so that the balls according to FIG. 4 remain securely in the pockets of the shaping surface 36.

Another advantage that is achieved with the inventive design of the torque sensing device, is that an additional spring, usually in the drive motor driven disc pair is included, for example, a plate spring, can be omitted. A spring which is usually present in the driven-side disk pair can likewise be dispensed with or made weaker.

The invention can be used with substantially all conical-pulley transmissions, in which the torque transmission from the drive motor to the belt transmission takes place via a torque sensor integrated into the belt transmission, which works with rolling elements to support mutually supporting form or ramp surfaces, which can be concealed relative to one another and changed in their axial spacing are.

LIST OF REFERENCE NUMERALS

input shaft

hard disk

movable disk

annular flange

support ring

piston

adjusting chamber

axial

supply

sensing piston

pressure chamber

form surface

ring member

Bullet

Cage

input gear

camp

external teeth

axial

drain hole

drain channel

pressure chamber

annular chamber

axial

radial channel

Claims

Patentansorüche

A method for improving the towing ability of a vehicle equipped with a conical pulley transmission, the method comprising interrupting torque transmitting engagement between the belt pulley and the vehicle drive motor with the torque applied to the pulley wrap transmission and the hydraulic pressure applied to the belt pulley flywheel transmission.

2. The method of claim 1, wherein the torque transmitting engagement by Hydraulikdruckbeaufschlagung the Kegelscheibenumschiingungsgetriebes is recoverable.

3. cone pulley pair for a conical pulley, which conical pulley pair includes: an input shaft (10) which is rigidly connected to a fixed disc (12), an axially displaceable on the shaft and non-rotatably mounted travel disc (14), an input member driven by a drive motor (40 ), a torque sensing means (34, 35, 37) having a first component (36) in torque transfer engagement with the input member having first molding surfaces (35) and a second component (28) having second molding surfaces in torque transmitting engagement with the disk (34) and arranged between the molding surfaces rolling elements (37), which forming surfaces are formed such that with increasing torque acting between the forming surfaces, the mold surfaces from each other while rolling the rolling elements arranged between them against the mold surfaces to each other urging force, wherein the Shapes such ebildet are that with a small or missing, they force each other to each other such that the rolling elements overflow the molding surfaces and the torque transmission between the first component and the second component is interrupted.

4. pair of conical disks according to claim 3, wherein the torque transmission is interruptible only when acting from the windshield forth torque (dragged gear).

5. conical disk pair according to claim 3 or 4, wherein the first component with a on the input shaft (10) mounted input gear (40) non-rotatably connected ring member (36), at its side facing away from the input wheel end face, the first molding surfaces (35) are formed, and the second component is a sensing piston (28) which surrounds the input shaft and is axially displaceable relative to the input shaft, a pressure chamber (32) is arranged between it and the displacement disk into which an inlet channel (46) which can be acted upon by hydraulic pressure from the pressure source a flow channel (48, 50) leads, wherein the effective cross section of an inlet and / or drain opening is changeable by the axial position of the sensing piston.

6. cone pulley pair according to one of claims 3 to 5, wherein the rolling elements are formed as in a cage (38) held balls (37).

7. pair of conical disks according to claim 6, wherein the molding surfaces radially outward transition into ramps formed without ramps and the balls are radially movable, so that the balls run due to centrifugal force in the absence of hydraulic pressure and high speeds on largely flat tracks.

8. Conical disk pair according to claim 6, wherein the balls are biased axially in the direction of pockets which are formed in the first or the second molding surfaces.