DE102010006417A1 - Traction drive of an internal combustion engine with starter generator - Google Patents

Abstract

The invention relates to a traction mechanism drive (1) of an internal combustion engine, designed as an accessory drive, in which a belt as elastic traction mechanism (2) connects the pulleys (3, 4) of a drive or output element of the traction mechanism drive (1), characterized in that one Pulley (3) is assigned an automatically adjustable pendulum decoupler (10), which includes two deflection rollers (11, 12) rigidly connected to one another via a device (9), via which a traction device guide is set, in which the traction means (2) between the deflection rollers (11, 12) surrounds the pulley (3) in some areas.

Description

Field of the invention

The invention relates to a traction mechanism drive of an internal combustion engine, designed as an auxiliary drive, in which a belt as an elastic traction means, the pulleys of the crankshaft, at least one traction-driven starter generator and / or another unit, a clamping system and at least one tensioning roller connects.

Belt drives for internal combustion engines require a tensioning device in order to avoid undesired belt slippage and to compensate for belt expansions.

To ensure a sufficient bias of the traction means, in particular an elastic belt, the traction mechanism drive comprises a clamping system. Traction drive, which is provided for an internal combustion engine and includes the drive of a traction-driven starter generator. In order to avoid a start delay, a sufficient pretensioning of the traction means is required in the start mode. The tensioning system comprises a torsionally positionally positioned support body, on which indirectly or directly a pivotable, resiliently supported on the traction means, rotatably mounted tension roller is arranged.

So far, an electric drive motor was used to start of internal combustion engines for passenger cars, which engages in the starting phase via a pinion in a ring gear of the flywheel. Today's internal combustion engines are partially provided with a starter generator in which the electric drive motor is integrated in the generator. This results in starting the engine, a change in the usual kinematic conditions in the belt drive, since the starting drive motor temporarily tows the crankshaft. With only one tension roller on the slack side of the driving crankshaft, there is an undesirable belt slippage and adverse belt vibrations with the relatively high and sudden onset of torque of the starter generator.

A traction drive, which includes the drive of a starter generator, requires almost continuous, d. H. regardless of the operating state of the internal combustion engine, the start mode or normal operation, a sufficient biasing force of the traction means. In start mode, the starter generator operating as an electric motor drives the internal combustion engine. After the start of the engine there is a reversal, in which a drive of the starter generator via the internal combustion engine. In the generator mode, the starter generator supplies the internal combustion engine and the electrical system of the motor vehicle with electrical energy. Depending on the operating mode of the internal combustion engine, a torque is introduced from the starter generator or the internal combustion engine via the corresponding pulleys in the traction means. This is associated with a change of the empty strand and the traction or a change of the torque direction in the Zugmitteltrum between the pulleys of the crankshaft and the starter generator.

The document EP 1 122 464 A1 shows a traction drive, which includes the drive of a starter generator. The associated clamping system comprises a rotatably arranged support body with two tension rollers, which are positioned with differing lever arms to the axis of rotation of the support body. The arrangement of the clamping system provides that adjusts a traction means, in which the traction means surrounds the pulley of the starter between the tension rollers of the clamping system.

The one from the document JP 010 059 555 A known traction drive also includes a starter generator. To realize a sufficient biasing force of the traction means in both the starting mode and when the internal combustion engine to two self-acting clamping systems are provided. A first tensioning system comprises a tensioning pulley which is supported on the traction mechanism between the pulleys of the crankshaft and the starter generator. The tension roller of the second tensioning system is supported on a downstream of the starter generator section of Zugmitteltrums. The structure provides that in the start mode, the first tensioning system is lockable or lockable, to achieve a biased traction means between the starter generator and the pulley of the crankshaft. When the engine is running, the lock is released, so that the guided on the traction means roller of the clamping system can adjust automatically.

Summary of the invention

The object of the present invention is to realize a vibration-calm traction drive with associated starter generator.

This problem is solved according to the invention by a pendulum decoupler, which is associated with a pulley of a drive or driven member of the traction mechanism. The self-adjusting pendulum decoupler comprises two deflection rollers rigidly connected to one another via a pivotable device. The pivotable device is mounted so that each one pulley in Zugmitteltrum before and one in the Zugmitteltrum after a Pulley of the traction drive is positioned. During the starting phase, in which the internal combustion engine is driven by the starter generator, the pendulum decoupler, which can also be referred to as a pendulum, automatically reacts to a change in the tensile medium elongation or traction medium tension in the pulling strand by turning itself out of the shoot. At the same time, the deflection roller is screwed in the empty strand at the same angle in the drive and thereby compensates for an occurred belt elongation. The pendulum decoupler thus causes a nearly constant looping of the associated pulley.

The degree of freedom of the pendulum decoupler allows swinging or oscillation around the fulcrum in the operating state when rotational irregularities of the internal combustion engine occur. The system according to the invention thus allows length changes of the traction means in consequence of changes in the bias in the traction means and causes a balance of forces. Advantageously, the pendulum decoupler compensates for the transmission of the rotational irregularity in the traction mechanism drive and causes a uniform speed curve, whereby all components of the traction drive are relieved. In the installed state, this creates a Zugmittelführung, in which the traction means between the pulleys partially surrounds the pulley of the starter generator. Regardless of the operating state of the internal combustion engine, a deflection roller is assigned to the empty strand and the further deflection roller is assigned to the tensile strand of the traction mechanism drive. Advantageously, the pendulum decoupler is both in a starting phase, in which the internal combustion engine is driven via the starter generator, as well as in generator mode, when the drive is made by the internal combustion engine, automatically adjustable.

The arrangement of the pulleys and the operation of the pendulum decoupler always allow in all operating conditions a constant, a Zugmittelschlupf advantageously avoiding wrap of the traction means on the associated pulley. Consequently, the inventive concept improves the functionality and causes increased fatigue strength, combined with an increased life of the traction mechanism drive. Furthermore, the invention allows reduced biasing and / or damping forces in the traction mechanism, so that traction means with a modified rigidity and / or dimensioning can be used. Since in conjunction with the pendulum decoupler, the risk of slippage also drops, it makes sense to use traction means without special coatings. Advantageously, the pendulum decoupler according to the invention allows due to the lower load, the use of smaller dimensioned components such as traction and rolling bearings, which sets a high savings potential in terms of cost, weight and space.

Further advantageous embodiments are the subject of the dependent claims 2 to 10.

Advantageously, the invention allows interaction of the pendulum decoupler with the pulley of the crankshaft. The pendulum decoupler is arranged so that the pulley of the crankshaft between the pulleys of the device is placed. The assignment of the pendulum decoupler according to the invention on the crankshaft pulley advantageously causes an always constant Umschlingungsgrad the traction means on the pulley. Alternatively, it makes sense to assign the pendulum decoupler according to the invention of a pulley of any aggregate of the traction drive.

A component-optimized concept of the pendulum decoupler provides that its device has a pivot point which coincides with an axis of rotation of the associated pulley. For this purpose, for example, the pendulum decoupler can be fixed to a Zentralverschaubung, on the same time the pulley of the crankshaft is attached.

To create a symmetrical structure of the device, a lever arm or radius between the axes of the pulleys and the pivot point of the device is designed to match.

According to a further inventive design is provided that in addition to a matching lever arm, the device provides an axial distance between the pulleys, thereby adjusting a wrap angle of the traction means on the pulley α of ≥ 180 °.

A further preferred embodiment of the invention provides that the device of the pendulum decoupler includes a damping device in the fulcrum. For this purpose, it is advisable to arrange a spring-loaded friction disc as a damping device in a hub of the device. Alternatively, the pivot bearing may include a mechanical or hydraulic damping element.

The invention also includes a measure to relieve the device mounting of the pendulum decoupler during the starting process of the internal combustion engine. For this purpose, it is provided to align the Zugtrum associated pulley of Pendeldecouplers so that sets an unrestricted straight course of the traction device between the belt shots of the crankshaft and the generator. In this drive design, during the take-off phase, a complete extension of the take-off drag is established, associated with a limited angle of rotation or with a limitation the working path of the pendulum decoupler and an advantageous reduced axle load of the respective pulley.

A traction mechanism drive including a pendulum decoupler incorporating a starter generator advantageously requires no second clamping system. Furthermore, the pendulum decoupler leads to an effective relief of the traction mechanism tensioning system, which are unchanged assigned exclusively to the slack side and can be optimally designed for regenerative operation. The construction of the pendulum decoupler according to the invention can be advantageously combined with known clamping systems, for example with a hydraulic, a mechanically rotary or a linear acting clamping system in conjunction with a tensioning roller. In addition, offers a pivotable, acted upon by a power generator or generator tensioner as a clamping system, for combination with the pendulum decoupler according to the invention.

Brief description of the drawings

The invention will be explained in more detail with reference to exemplary embodiments in a total of three figures. Show it:

1 a schematic representation of a traction mechanism according to the invention with starter generator and a pendulum decoupler in a neutral position;

2 the traction mechanism according to 1 in a start cycle;

3 the traction mechanism according to 1 in a regenerative operating state.

Detailed description of the drawings

The 1 shows a specific for driving units of an internal combustion engine, also referred to as ancillary drive, clockwise circulating traction drive 1 , This includes as traction means 2 an elastic belt that connects pulleys of individual drive or driven members or individual units like the pulley 3 a crankshaft, the pulley 4 a starter generator 5 as well as the pulleys 6 and 7 other aggregates. The traction device 2 is still between the pulleys 4 and 6 on a pulley 8th guided. The traction drive 1 continues to close one of the pulley 3 the crankshaft associated Pendeldecoupler 10 a, consisting of a pivotable, two pulleys 11 . 12 comprehensive device 9 , Due to the relatively close assignment of the pulleys 11 . 12 with a matching radius or lever arm "s" on the device 9 are fastened, there is a wrap angle "α" of ≥ 180 ° of the traction device 1 on the pulley 3 one. The large wrap angle "α" allows a slip-free drive and causes a delay-free, fast start of the engine in the start mode.

The compact design of the pendulum decoupler 10 underscores a pivot point 13 the device 9 with a rotation axis 14 the pulley 3 match. To illustrate a symmetrical structure, the pulleys 11 . 12 in a matching distance "s" or lever arm to the fulcrum 13 the device 9 positioned. The pendulum decoupler 10 can continue to vibrational contact of the traction drive 1 include a damping device. For this purpose, for example, offers, in a hub of the device 9 in the area of the fulcrum 13 to arrange a damping device. Alternatively, the fulcrum bearing may include a mechanical or hydraulic damping element.

The one to a fixed point of articulation 15 For example, the internal combustion engine swiveling starter generator 5 simultaneously forms a clamping system of the traction mechanism drive 1 , The starter generator, which can also be referred to as a generator tensioner 5 is for this purpose by a force acting counterclockwise force 16 subjected to a sufficient bias of the traction device 2 to ensure. As a means of power 16 For example, a mechanical spring means, a mechanical-hydraulic, electro-hydraulic or electromagnetically acting actuator is suitable.

The 2 and 3 show the traction drive 1 in alternative operating states. Components with the 1 match, are provided with the same reference numerals. The following description is therefore limited essentially to the different structure or the different arrangement of individual components.

The 2 shows the traction drive 1 in start mode, where the starter generator 5 in the internal combustion engine drives. In this phase forms a belt drum 17 of the traction device 2 between the pulleys 3 and 4 , the pulley 12 of the shuttle decoupler 10 is assigned, a Zugtrum. In the start mode forms a Riementrum 18 between the pulleys 3 and 7 of the traction mechanism drive 1 the empty strand. To relieve the storage and / or limiting the working path of the device 9 is an interpretation of the traction drive 1 or the shuttle decoupler 10 provided that ensures a complete extension of the draft. In this case, the angle of rotation of the counterclockwise twisting pendulum decoupler 10 limited, but without influence on the wrap angle "α" of the traction device 2 ,

The 3 shows the traction drive 1 in generator operation of the starter generator 5 , The drive of the starter generator takes place 5 over the crankshaft associated pulley 3 , Deviating from the start mode, the belt is in regenerative operation 17 to the Leertrum and the Riementrum 18 to Zugtrum. Due to the changed drive, the pendulum decoupler swings 10 in a clockwise direction, eliminating the pulley 12 sufficient pretensioning of the belt 17 and thus ensures the empty run.

LIST OF REFERENCE NUMBERS

1

traction drive

2

traction means

3

pulley

4

pulley

5

starter generator

6

pulley

7

pulley

8th

idler pulley

9

contraption

10

Pendeldecoupler

11

idler pulley

12

idler pulley

13

pivot point

14

axis of rotation

15

articulation

16

power means

17

belt strand

18

belt strand

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

• EP 1122464 A1 [0006]
• JP 010059555 A [0007]

Claims (10)

Traction drive of an internal combustion engine, designed as an accessory drive, in which a belt as an elastic traction means ( 2 ) the pulley ( 4 ) of the crankshaft and at least the pulley ( 4 ) of a starter generator ( 5 ) and / or another aggregate of a clamping system, characterized in that the pulley ( 4 . 6 . 7 ) of a drive or driven member of the traction mechanism drive ( 1 ) an automatically adjustable pendulum decoupler ( 10 ), the two via a pivotable device ( 9 ) rigidly interconnected pulleys ( 11 . 12 ), via which adjusts a traction means guide, wherein the traction means ( 2 ) between the pulleys ( 11 . 12 ) of the device ( 9 ) a pulley ( 4 . 6 . 7 ) encloses areas. Traction drive according to claim 1, characterized in that the pendulum decoupler ( 10 ) with the pulley ( 3 ) of the crankshaft cooperates. Traction drive according to claim 1, characterized in that a pivot point ( 13 ) of the device ( 9 ) with a rotation axis ( 14 ) of the pulley ( 3 ), which corresponds to the shuttle decoupler ( 10 ) assigned. Traction drive according to one of the preceding claims 1 to 3, characterized in that in conjunction with the pendulum decoupler ( 10 ) the traction means ( 2 ) the pulley ( 3 ) encloses with a wrap angle "α" of ≥ 180 °. Traction drive according to one of the preceding claims 1 to 4, characterized in that a lever arm or radius "s" between the pulleys ( 11 . 12 ) and a pivot point ( 13 ) of the device ( 9 ) matches. Traction drive according to one of the preceding claims 1 to 5, characterized in that the device ( 9 ) of the shuttle decoupler ( 10 ) in the fulcrum ( 13 ) includes a damping device. Traction drive according to claim 6, characterized in that in a hub of the device ( 9 ) A spring-loaded friction disc is provided as a damping device. Traction drive according to one of the preceding claims 1 to 7, characterized in that during the starting process of the internal combustion engine that the Riementrum ( 17 ) associated pulley ( 12 ) of the shuttle decoupler ( 10 ) is aligned so that a stretched course of the traction means ( 2 ) between the pulleys ( 3 . 4 ) of the crankshaft and the starter generator ( 5 ). Traction drive according to one of the preceding claims 1 to 8, characterized in that to achieve a sufficient bias of the traction means ( 2 ) a hydraulic, mechanical rotary or a linear acting clamping system is used in conjunction with a tensioner. Traction drive according to one of the preceding claims 1 to 9, characterized in that a pivotable of a force means ( 16 ) acted generator or starter generator ( 5 ) is provided as a clamping system.

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