DE102012218455A1 - Tensioning device for traction drive, has control device, which is adapted and designed to adjust biasing element as function of dynamic operating state, which includes components and devices associated with traction drive - Google Patents

Abstract

The tensioning device has an adjustable biasing element for realizing a bias voltage of a traction unit. A control device is provided, which is adapted and designed to adjust the biasing element as a function of a dynamic operating state. The dynamic operating state includes components and devices associated with the traction drive. The dynamic operating state includes a load condition or a rotational speed of a driving machine, where the driving machine is an internal combustion engine. An independent claim is included for a method for controlling a tensioning device.

Description

The present invention relates to a tensioning device for a traction drive with variable biasing force and a method for controlling such a tensioning device.

Belt drives found in internal combustion engines or internal combustion engines u. a. Application for driving ancillaries. The torque originating from the internal combustion engine is subject to periodic fluctuations due to the ignitions. The non-uniform torque is introduced via a crankshaft pulley in an accessory belt drive, while at the same time abut speed-dependent load moments on the ancillaries. Due to the periodic instantaneous excitation of the crankshaft speed fluctuations of the discs are caused in the belt drive, which in turn - because the discs can rotate relative to each other - lead to fluctuations in Trumkräften. These fluctuations can lead to a strong decrease in the Trumkraft and thus slippage and unwanted noise on the one hand and on the other hand cause excessive increases in the Trum- or axle forces. For these reasons, automatic belt tensioner are used, which ensure the lowest possible Trumkraftschwankung in operation. However, it is usually not possible to completely bring these Trumkraftschwankungen by belt tensioner to disappear. The Trumkräfte therefore have a mean value defined by the belt biasing force by which then the periodic fluctuations occur.

The amount of excitation from the motor depends on the load condition of the motor, the auxiliary load and the current speed. Maximum suggestions usually occur at low speeds and simultaneous engine and aggregate full load or when starting the engine. In such states, an increased preload force is needed, while in other load cases, a significantly reduced preload is functionally sufficient. The biasing force of a belt drive is conventionally designed for the maximum load operating points, although these are relatively infrequent. For this reason, the belt drive is operated in a large part of its life with an unnecessarily high biasing force.

It is a design goal to set the average tension as low as possible, but high enough so that the belt drive fulfills all functional requirements. This also friction losses in the bearings of the pulleys and deformation losses in the belt can be reduced, which contributes to an overall reduction in CO ₂ emissions. Usually there is a high potential for saving CO ₂ in the belt drive.

From the DE 10 2007 051 228 A1 It is known to provide a traction drive with an active, in particular pneumatic or hydrodynamic clamping system in order to realize different biasing forces for the two operating cases of an alternator, namely a starter motor operation on the one hand and a generator operation on the other hand. For this purpose, designed as a combined spring-damper element clamping element is provided, wherein a coil spring is connected in parallel with a so-called pneumatic or hydrodynamic muscle. The properties of the pneumatic muscle are adaptable by a compressor, alternatively the properties of the hydrodynamic muscle by partial or full interlocking of one-way valves or by a fluid quantity adjustment depending on the respective operating case. That from the DE 10 2007 051 228 A1 known system is based on a complex adjustment system, among other things using a pneumatic accumulator. It is therefore not possible to optimally adjust the average tension during operation.

An object of the present invention is to provide a tensioning device for a variable-prestressing traction drive which avoids the disadvantages of the prior art. In particular, an object of the present invention is to provide a tensioning device for a traction drive with variable bias, which allows optimal adjustment of the average Trumkraft during operation. Another object of the invention is to reduce friction losses in the bearings of Zugmitteltrieben, deformation losses in traction devices of traction drives and slip and peak loads in the traction means to increase especially during operation, the transmission efficiency and thus also the fuel consumption and the CO ₂ emissions of a To reduce internal combustion engine and to extend the life of bearings, pulleys and traction means.

The above object is achieved by a tensioning device according to the invention with the features of claim 1, by a method for controlling a tensioning device with the features of claim 10 and by tensioning devices according to the invention with the features of claims 11 and 12.

A tensioning device for a traction mechanism drive has at least one adjustable biasing element for realizing a bias of a traction means. According to the invention a control device is further provided which is adapted and arranged, the biasing element in dependence on to adjust at least one dynamic operating state.

A traction drive has at least one drive, such as an internal combustion engine, a turbo-engine or other turbomachine, a wind or water wheel, an electric motor or the like, a driven unit, such as a generator, a compressor, fan or other fluid flow machine, an industrial plant or the like , and a traction means, such as a belt, a belt, a chain or a rope, wherein the traction means is wound around wheels, which are respectively connected to the drive and with the unit, to the force of the drive to transfer to the unit via the traction means.

In contrast to a short-term adaptation to static load cases, such as the load case of the starter operation, an adjustment of the biasing member in response to at least one dynamic operating condition allows adjustment of the biasing force to time-varying requirements during operation. As a result, friction and deformation losses can be reduced, the transmission efficiency of the traction drive increased and the fuel consumption and the CO ₂ emissions of the internal combustion engine can be reduced. Furthermore, the life of bearings, discs and traction means can be extended due to reduced slippage, reduced friction and reduced peak loads.

Operating conditions of components and / or devices connected to the traction mechanism drive can be understood as a dynamic operating state, such as a load state and / or a rotational speed of an internal combustion engine or a load state of an auxiliary device connected to the traction drive. Thus, an adjustment is made to those parameters that have a significant influence on the Trumkräfte. If necessary, other parameters such as vehicle speed, gear selection, pedal position, or the like may also be included.

If the biasing member comprises a pulley, clamping forces can be particularly easily applied to the traction means.

A simple adjustment is possible if the clamping device has a particular mechanical, hydraulic, pneumatic, electric or magnetic drive device which acts directly or indirectly on an actuator movable on a defined path of the guide roller. It is particularly preferred if the actuator is linearly movable or pivotable. However, it is also a multi-joint guide or other link guide conceivable.

In a preferred embodiment, the drive device has an electric motor and a preferably self-locking spindle or worm wheel drive, which converts a rotational movement of the electric motor into a linear movement of an actuator of the deflection roller. In an alternative embodiment, the drive means acts directly or indirectly on a spring retainer of a torsion spring, wherein the torsion spring is connected at one end to the spring retainer and at another end connected to a pivot lever, wherein the pivot lever is connected to the tension roller so that he acts in the tensioning direction on the tensioning roller. Both embodiments have a robust and simple structure and rely on proven components. Both forms are modifiable so that any way the pulley can be displayed on levers, joints or facial expressions.

Particularly preferably, the control device is set up and adapted to adjust the biasing member such that there is a biasing force which is minimally required to ensure a function of the traction mechanism in a respective dynamic operating condition. This means that, depending on the dynamic operating state, it is possible to set a prestressing force which is high enough to reliably ensure the transmission, ie with the least possible slip, and at the same time avoid excessive frictional and deformation losses due to an unnecessarily high prestressing force.

• a) Bestimmen des zumindest einen dynamischen Betriebszustands und
• b) Verstellen des Vorspannelements in Abhängigkeit von dem zumindest einen bestimmten Betriebszustand derart, dass sich eine Vorspannkraft ergibt, welche zur Sicherstellung einer Funktion des Zugmitteltriebs minimal erforderlich ist.

A suitable method for controlling the above-described tensioning device comprises the following method steps:

• a) determining the at least one dynamic operating state and
• b) adjusting the biasing element in dependence on the at least one specific operating state such that a biasing force results, which is minimally required to ensure a function of the traction mechanism drive.

According to a further aspect of the invention, the tensioning device has a drive device for adjusting the biasing element, wherein the biasing element comprises a deflection roller for the traction means, wherein the drive means comprises an electric motor and a preferably self-locking spindle or Schneckenradantrieb, the rotational movement of the electric motor in a linear - or pivotal movement of an actuator of the tensioner pulley converts.

According to a further aspect of the invention, the biasing member comprises a deflection roller for the traction means, wherein the deflection roller is pressed by a torsion spring and a pivot lever on the traction means, and wherein a spring receiving the torsion spring is rotatable by a drive means about a torsion axis of the torsion spring.

In the clamping devices according to the last-mentioned two aspects of the invention, the biasing element can be controlled in a particularly advantageous manner as a function of at least one dynamic operating state, as a result of which the advantages described above can also be achieved. They each have a robust and simple design and rely on proven components.

Further features, objects and effects of the invention will become apparent from the description and the accompanying drawings. In this case, features and details that are described in connection with the clamping device according to the invention apply, of course, also in connection with the method according to the invention and in each case vice versa, so that with respect to the disclosure of the individual invention aspects always reciprocal reference is or may be.

In the drawings is in:

1 1 is a schematic illustration for illustrating a structure of a belt drive with dynamic tension adjustment as a basic embodiment of the present invention;

2 a schematic representation for illustrating a first embodiment variant,

3 a schematic representation for illustrating a second embodiment variant,

4 a view in the direction of an arrow "IV" in 3 and

5 a schematic block diagram for illustrating a control-technical context in an inventive arrangement shown.

In 1 is a belt drive 1 as a basic embodiment of the present invention shown schematically.

As shown in 1 has the belt drive 1 a drive-side pulley 2 and a load-side pulley 3 on. A belt 4 is around the pulleys 2 . 3 looped. In this embodiment, the drive-side pulley 2 in normal operation of an internal combustion engine (not shown in detail), possibly via a transmission (not shown in detail), driven. The load-side pulley 3 drives a generator (not shown in detail), also referred to as an alternator on. According to the direction of rotation arrow indicated in the figure on the drive-side pulley 2 is the upper part of the belt in the illustrated load case as Lasttrum 5 , the lower part as Lostrum 6 Are defined. It is understood that in a starter operation, in which the generator drives the motor, the load reverses, so the lower part of the belt 4 to the load area, the upper part becomes the Lostrum.

The tension of the belt 4 is through a clamping arrangement 7 regulated. The clamping arrangement 7 is a clamping device in the context of the invention. As shown in 1 the tensioning arrangement has two deflection rollers 8th and two tension drives 9 on. Each arrangement of pulley 8th and tension drive 9 can also be understood as a clamping device in the context of the invention. As indicated in the figure by respective double arrows, by each tensioning drive, the associated deflection roller 8th linear positionable back and forth. It is understood that this representation is schematic; instead of a linear positioning, the pulleys 8th Also stored on swing levers or multi-jointed arms or guided in scenes and on any curves from and to the Trumen 5 . 6 of the belt 4 be pivotable or feasible.

In 2 is an adjustable pulley 8th with linear guide clamping drive 9 ' as a variant of the present invention shown schematically.

A bearing shaft 10 the pulley 8th is in a lifting frame 11 stored. The lifting frame 12 indicates one of the belt 4 facing away from a base plate 12 on. The base plate 12 has a nut bore in which a spindle 13 running. The spindle 13 will be with a stationary electric motor 14 connected.

On the other hand, the bearing shaft 10 the pulley 8th in a guide groove 15 guided. The guide groove 15 is part of a fixed facial expression (not shown in detail). The facial expressions may, but need not, be with a housing of the electric motor 14 be rigidly connected. In variations of this embodiment is not the shaft 10 but is the lifting frame 11 by means of a driver, such as a pin or a component overhang, guided in a groove of a facial expression or vice versa.

For positioning the pulley 8th drives the electric motor 14 the spindle 13 that are in the Nut bore of the base plate 12 turns and thus the lifting frame 11 to or from the electric motor 8th moved (see double arrow in 2 ). By in the lifting frame 11 stored and in the guide groove 15 guided bearing shaft 10 becomes the pulley 8th moved and tensioned or relaxed thus the belt 4 ,

In 3 is a pulley 8th with torsion spring tensioning drive 9 '' as a variant of the present invention shown schematically. 4 shows the arrangement of 4 in the direction of an arrow IV in 3 ,

As shown in 3 and 4 is a bearing shaft 10 the pulley 8th at a first end 16a of the pivot lever 16 stored. The swivel lever 16 is with his second end 16b at a first end 17a a prestressed torsion spring 17 attached. At her second end 17b is the torsion spring 17 in a spring recording 18 added. The spring recording 18 is with an adjuster 19 connected.

As in 4 shown, the pivoting lever urges 16 by means of the tension of the torsion spring 17 the pulley 8th in the direction of the belt 4 , ie in the clamping direction (see arrow on the pivot lever 16 in 4 ). For positioning the pulley 8th becomes through the Versteller 19 a torque (arrow 20 in 3 ) on the torsion spring 17 applied. The torque 20 Depending on the positioning direction is a reinforcing (positive with respect to the bias voltage) or dissolving (negative in relation to the bias) differential torque.

The Versteller 19 may comprise a stepper motor (not shown in detail) or be coupled with such via a worm gear (not shown in detail). In another alternative, the adjuster 19 have a piezo actuator. However, the invention is not limited to these alternative embodiments.

In 5 is a control-technical context of an inventive arrangement shown schematically.

As shown in 5 is a control unit 21 with two clamping drives 9 , an internal combustion engine (a motor / gear unit) 22 , an alternator 23 and a driven by the belt drive accessory 24 , such as a water pump or air conditioning compressor, connected by signal technology. The control unit receives signal lines (dashed arrows) 21 Signals from the engine / transmission unit 22 , the alternator 23 and the accessory 24 wherein the transmitted signals correspond to dynamic operating states of these devices. For example, an operating state of the engine / transmission unit becomes 22 is described by a rotational speed N and a torque T, an operating state of the alternator 23 by a rotational speed N, a torque T and an electric power Q, and becomes an operating state of the accessory 24 by a rotational speed N of a fan motor (not shown in detail) described. On the output side, the controller sends 21 Control signals S to the clamping drives 9 to the associated pulleys 8th to position. From the tension drives 9 If necessary, a signal X is returned which represents a travel or a rotation angle of a stepping motor or the like. Sensors for detecting the mentioned variables are in the 5 not shown in detail.

In the control unit 21 are given relationships between the received operating conditions, a respective position of the pulleys 8th and the strand tension is evaluated in order for the respective overall dynamic operating condition resulting from the individual dynamic operating conditions, suitable values for the average bias of the load and Lostrums the traction means and suitable positions of the pulleys 8th to investigate. This will be suitable control signals S for the clamping drives 9 generated and transmitted to this. The relationships may take the form of tables, maps, and / or mathematical equations and / or equation systems in the controller 21 be deposited and can also consider their own dynamic stress states of the traction device.

It is understood that the control unit 21 in addition to the illustrated a plurality of further input signals, which correspond to a variety of other operating conditions such as a vehicle speed, a gear selection, a pedal position, etc., receive and process.

While in the in 3 and 4 embodiment shown a resilient mounting of the guide roller 8th is provided at the in 2 embodiment shown described no suspension. Nevertheless, a suspension may also be provided there, and in both cases damping may be provided.

According to one aspect of the invention is proposed for variable adjustment of the biasing force to direct a pulley by means of a mechanically, hydraulically, pneumatically, electrically or magnetically driven device targeted in the belt drive and thereby to change the biasing force in the belt. The position of the pulley can be adjusted depending on the engine speed or load condition of the engine or ancillaries so that the respective minimum required preload force in the belt drive results, which is necessary to ensure its function.

It is conceivable, for example, the use of a self-locking spindle or Schneckenradantriebes over which by means of an electric motor, a rotational movement is converted into the linear movement of the guide roller. 2 shows an example of a possible arrangement for such a spindle drive. In addition to linear movements of the pulley solutions are possible in which the deflection roller is pivoted, for example on a circular path or another contour in the belt drive.

Another way to adjust the biasing force of the belt drive to the current load condition, is to adjust the clamping force of the belt tensioner targeted. This is done with the help of in 3 . 4 sketched device, the bias of the tensioner spring by means of a suitably generated torque (for example, mechanical, electrical, hydraulic, magnetic, pneumatic) adapted as needed. In the case of a torsion bar spring, for example, the relative rotation of both spring ends can be adjusted to each other here. Such a procedure is possible for the clamping elements of belt, chain and belt drives.

Belt drives are often designed with a high preload force, which is only required in a small proportion of the service life. By a variable adjustment of the preload force depending on the load condition of the engine and ancillaries as well as the engine speed, it is possible to significantly reduce energy losses in the belt drive due to bearing friction and deformations in the belt. The belt drive can thus be adjusted so that it produces minimal energy loss while ensuring the function. This in turn can lead to a significant reduction in fuel consumption and CO ₂ emissions.

The positionable pulley for preload adjustment does not require special belt drives, but can be used in any belt drives. Since most belt drives already have pulleys, the use of the system is possible with very little effort and the layout of the belt drive does not need to be fundamentally changed.

Since tensioning elements are used in most of the belt transmissions anyway, the tensioning element with adjustable preload can also be easily integrated into any belt-type transmission without a great deal of extra effort.

The invention can be used in addition to belt drives for toothed belt or chain drives. In addition to an internal combustion engine and turbomachinery, electric motors, wind turbines, water wheels or other forms of drive can be used as a drive for the traction drive. The application of the invention is not limited to motor vehicles, but may also have the described advantages in conveyors, cable cars or other applications.

The invention has been described above with reference to preferred embodiments, variants, alternatives and modifications and illustrated in the figures. These descriptions and illustrations are purely schematic and do not limit the scope of the claims, but are merely illustrative thereof. It is understood that the invention can be embodied and modified in many ways without departing from the scope of the claims.

LIST OF REFERENCE NUMBERS

1

belt drive

2

Pulley, drive side

3

Pulley, load side

4

belt

5

load strand

6

slack run

7

tensioning assembly

8th

idler pulley

9, 9 ', 9' '

tensioning drive

10

bearing shaft

11

lifting frame

12

baseplate

13

spindle

14

electric motor

15

guide

16

clamping lever

16a, 16b

Ends of the clamping lever 16

17

torsion spring

17a, 17b

Ends of the torsion spring 17

18

spring mount

19

adjuster

20

righting moment

21

control unit

22

Engine / transmission unit

23

alternator

24

accessory

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 102007051228 A1 [0005, 0005]

Claims (12)

Clamping device for a traction mechanism drive, with at least one adjustable biasing element for realizing a bias voltage of a traction device, characterized in that a control device is provided which is adapted and adapted to adjust the biasing element in response to at least one dynamic operating condition. Clamping device according to claim 1, characterized in that the at least one dynamic operating state comprises operating states of the traction mechanism connected to the components and / or devices. Clamping device according to claim 1 or 2, characterized in that the at least one dynamic operating state includes a load state and / or a rotational speed of a prime mover, wherein the prime mover is preferably an internal combustion engine. Clamping device according to one of the preceding claims, characterized in that the at least one dynamic operating state comprises a load state of an accessory connected to the traction drive. Clamping device according to one of the preceding claims, characterized in that the biasing element comprises a deflection roller. Clamping device according to claim 5, characterized in that the clamping device has a particular mechanical, hydraulic, pneumatic, electric or magnetic drive device which acts directly or indirectly on a defined path movable, in particular linearly movable or pivotable, actuator of the tensioning roller. Clamping device according to claim 5 or 6, characterized in that the drive device comprises an electric motor and a preferably self-locking spindle or worm gear, which converts a rotational movement of the electric motor into a linear movement of an actuator of the deflection roller. Clamping device according to claim 5 or 6, characterized in that the drive device acts directly or indirectly on a spring receiving a torsion spring, wherein the torsion spring is connected at one end to the spring receiver and is connected at another end with a pivot lever, wherein the pivot lever with the Deflection pulley is connected so that it acts in the tensioning direction on the deflection roller. Clamping device according to one of the preceding claims, characterized in that the control device is set up and adapted to adjust the biasing member such that there is a biasing force which is minimally required to ensure a function of the traction mechanism in a respective dynamic operating condition. Method for controlling a tensioning device according to one of the preceding claims, wherein the method is characterized by the following method steps: a) determining the at least one dynamic operating state and b) adjusting the biasing element as a function of the at least one specific dynamic operating state such that a biasing force results, which is minimally required to ensure a function of the traction mechanism drive. Clamping device for a traction mechanism drive, in particular an internal combustion engine, with at least one adjustable biasing member for realizing a bias of the traction means, characterized in that further comprises a drive means for adjusting the biasing member is provided, wherein the biasing member comprises a pulley for the traction means, wherein the drive means comprises an electric motor and a preferably self-locking spindle or Schneckenradantrieb having a rotational movement of the electric motor converts into a linear movement of an actuator of the deflection roller. Clamping device for a traction mechanism drive, in particular an internal combustion engine, with at least one adjustable biasing member for realizing a bias of the traction means, characterized in that the biasing member comprises a pulley for the traction means, wherein the deflection roller is pressed by means of a torsion spring and a pivot lever on the traction means, and wherein a spring receiving the torsion spring by a drive means about a torsion axis of the torsion spring is rotatable.

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