DE10232328A1 - Traction mechanism gear for an internal combustion engine comprises a pre-tensioning device with a pre-tensioning roller and a pre-tensioning mechanism adjusted via a control element - Google Patents

Abstract

Traction mechanism gear (1) for an internal combustion engine comprises a first traction mechanism pulley (2) on a crankshaft, a second traction mechanism pulley (3) of a starter generator unit, and a pre-tensioning device (4) with a pre-tensioning roller (4.3) and a pre-tensioning mechanism (4.2) which can be adjusted via a control element (4.1). An Independent claim is also included for a process for tensioning a traction mechanism (5) using a pre-tensioning device. Preferred Features: A spring element transferring the pre-tensioning force is provided between the pre-tensioning mechanism and the pre-tensioning roller.

Description

The invention relates to a Traction mechanism of an internal combustion engine with a first pulley on a crankshaft, a second pulley on a starter-generator unit and a pretensioner with a biasing roller, wherein the first Pulley, the second pulley and the biasing roller on a traction device are connected.

It is already a traction mechanism intended for driving aggregates, in particular a starter-generator known, comprising a rotatably designed housing to which fixed the supported on the traction means Pulleys are arranged. In the operating mode of the starter-generator learns the housing a counter torque, whereby a deflection roller biases the traction means. Due to the new generation of starter generators, the traction mechanism is being the tensile load with higher Claimed peak values. Due to this higher tensile load is a higher Basic preload within the traction device necessary.

The invention is based on the object Clamping device for a traction mechanism such form and arrange that a optimum tension of the traction device is ensured.

The problem is solved according to the invention by in that the pretensioning device is a pretensioning gear which can be adjusted via a control element for the pretensioner having. This ensures that the traction means a Zugmittelvorspannung having the one to be transmitted Moments in each operating point or at least in the critical Operating points is adjusted. The wear of the traction device is due to reduced sinking continuous load. Also the bearing load the various Zugmittelscheiben and possible pulleys or pretensioning rollers is reduced. Ultimately, there is also a fuel economy, which corresponds to the reduced Zugmittelgetriebeverlusten. Advantageous Here is also that the traction means corresponding to the lower Continuous load can be made smaller. So it's enough a narrower traction means with less depth or less parallel to use arranged traction means.

For this it is advantageous that between the biasing gear and the biasing roller a biasing force transmitting Spring element is provided. The preload of the preload roller will cause excessive voltage spikes prevented within the traction device.

An additional possibility is according to a development, that the biasing gear is self-locking and optional a worm gear, a reel gear and / or a hydraulic transmission having. Due to the self-locking it needs after adjustment the biasing force no additional Energy to hold the bias.

Furthermore, it is advantageous that the Preload gear electromagnetic, electromechanical, hydraulic and / or is pneumatically formed. The use of a hydraulic or pneumatic transmission guaranteed low additional structural Effort and easier handling.

It is also advantageous for this that the operating point dependent Regelglied a control unit with a the operating points or assigned the characteristic of the internal combustion engine having system memory is. According to the various operating points of the internal combustion engine can thus set the optimal or maximum Zugmittelspannung become.

According to a preferred embodiment of inventive solution in the end provided for that the duration of the starting process of the internal combustion engine and / or during the Drive through the starter or generator and / or during one Boost function of the internal combustion engine, the traction means voltage is increased. This will cause a long-term overload the traction means and the bearings of the various Zugmittelscheiben prevented.

is of particular importance for the present Invention, that the traction means voltage with the shutdown of the internal combustion engine elevated and over the duration of the standstill energy-free until after the next start is held. For the upcoming start phase is a sufficient tension medium tension readily given to the after the startup again lowered to a necessary level becomes.

In connection with the training according to the invention and arrangement, it is advantageous that the tension means with the operation the ignition and increased before activation of the starter. Thus, a static Tension mean tension during prevents the parked internal combustion engine.

It is also advantageous that the Zugmittelspannung in. Dependence the traction means temperature or the engine temperature the pretensioner is varied. Depending on the training and composition of the traction means, the temperature of the traction device has considerable influence on the tension mean tension. This temperature-induced voltage change is thus taken into account.

Further advantages and details The invention are in the claims and in the description explained and shown in the figure. It shows:

1 a schematic representation of a traction mechanism with traction means and biasing device.

A traction mechanism 1 an internal combustion engine, not shown, has a plurality of traction pulleys, which via a traction means 5 be in frictional relationship with each other. A first pulley 2 a crankshaft, not shown, is provided with a biasing roller 4.3 a pretensioner 4 connected. The preload roll 4.3 in turn is directly with a second pulley 3 connected to a starter generator, not shown. Subsequently to the second pulley 3 is a third pulley 6 over the traction means 5 in force. From the first pulley 2 and of the third pulley 6 starting out the ends of the traction device 5 So a first end 5.1 and a second end 5.2 , to other units or traction pulleys, not shown.

By the rotation of the first pulley 2 Thus, all other traction pulleys and the traction pulleys, not shown further aggregates are set in rotation.

The pretensioner 4 indicates with the pretensioning roller 4.3 connected preload gear 4.2 on, which against an abutment 4.4 the internal combustion engine, not shown, is supported. The preload gear 4.2 is a rule member 4.1 associated, which via a control unit, not shown, the pivoting movement of the biasing roller 4.3 guaranteed. The preload gear 4.2 is designed as a spindle gear. Other transmissions such as a worm gear or hydraulic transmission are also possible. The pivoting movement in this case runs around a pivot axis 4.5 , By the pivoting movement, the length of the traction means, starting from the first pulley 2 over the pretensioning roller 4.3 to the second pulley 3 extended or shortened.

1

traction drives

2

first pulley

3

second pulley

4

biasing means

4.1

control element

4.2

biasing gear

4.3

biasing role

4.4

abutment

4.5

swivel axis

5

traction means

5.1

first The End

5.2

second The End

6

third pulley

Claims (9)

Traction mechanism ( 1 ) an internal combustion engine with a first pulley ( 2 ) on a crankshaft, a second pulley ( 3 ) a starter-generator unit and a biasing device ( 4 ) with a pretensioning roller ( 4.3 ), wherein the first pulley ( 2 ), the second pulley ( 3 ) and the pretensioning roller ( 4.3 ) via a traction means ( 5 ), characterized in that the pretensioning device ( 4 ) via a control element ( 4.1 ) adjustable preload gear ( 4.2 ) for the pretensioner ( 4 ) having. Apparatus according to claim 1, characterized in that between the biasing gear ( 4.2 ) and the pretensioning roller ( 4.3 ) is provided a biasing force transmitting spring element. Apparatus according to claim 1 or 2, characterized in that the biasing gear ( 4.2 ) is self-locking and optionally has a worm gear, a reel gear and / or a hydraulic transmission. Device according to one of the preceding claims, characterized in that the biasing gear ( 4.2 ) is electromagnetically, electromechanically, hydraulically and / or pneumatically formed. Device according to one of the preceding claims, characterized in that the operating point-dependent control element ( 4.1 ) is assigned a control unit having a the operating points or the characteristic of the internal combustion engine having system memory. Method for tensioning the traction means ( 5 ) by means of a pretensioning device ( 4 ) according to one of the preceding claims, characterized in that a) for the duration of the starting process of the internal combustion engine, the traction means voltage is increased and / or b) during the drive by the starter or generator, the traction means voltage is increased and / or c) during a boost Function of the internal combustion engine, the traction means voltage is increased. Method according to Claim 6, characterized that the traction means voltage with the shutdown of the internal combustion engine elevated and over the duration of the standstill energy-free until after the next start is held. Method according to claim 6 or 7, characterized that the traction means voltage with the actuation of the ignition and increased before activation of the starter becomes. A method according to claim 6, 7 or 8, characterized in that the traction means voltage in dependence of the traction means temperature or the engine temperature by the biasing means ( 4 ) is varied.