DE102005050542A1 - Belt tensioner for tensioner-damping-unit in internal combustion engine, has activation pair producing excitation that controls viscosity of fluid, which is magnetorheological fluid with high temperature stability - Google Patents

Abstract

The tensioner has a housing (10) filled with a fluid having changeable viscosity, where the fluid is a magnetorheological fluid with high temperature stability. A damping unit (15) is coupled with an oscillation exciter and is movably arranged in the housing. The damping unit is arranged such that the flow of the fluid is caused during its movement. An activation pair (16) is coupled with a power supply unit (19) that is controlled depending on a movement condition of the damping unit, and produces excitation that controls the viscosity of the fluid.

Description

Territory of invention

The The invention relates to a belt tensioner, in particular for tensioner damping elements for traction means in internal combustion engines, consisting of a sealed to the environment and with a viscosity modifiable liquid filled Housing, one movably arranged therein, coupled with a vibration exciter Damping element, which is arranged so that when moving a flow of their viscosity changeable liquid and one with one depending on the state of movement of the damping element regulated voltage source coupled activation pair for generation one is the viscosity which change their viscosity Fluid controlling Stimulation.

background the invention

such Belt tensioners are in the clamping systems known in the art by means of a spring-loaded friction disc (for example, a mechanical Spanner RSEMx) or by means of a throttle gap between a cylinder and a displacer (for example, a hydraulic tensioner / hydraulic tensioning element) realized.

Known Applications of viscosity modifiable liquids for active vibration damping are found, for example, in shock absorbers of motor vehicles, Drum bearings for washing machines, in the field of prosthetics, for example an artificial one Knee damper, and in the suspension of driver's seats for trucks.

In the DE 34 33 797 A1 discloses a belt tensioner, which consists of a deformable shaped housing on which on the one hand the motor rests, and on the other hand is fixed to a support structure. The housing is completely sealed to the outside and divided by a wall arranged at right angles to the loading direction into two chambers filled with electrorheological fluid. Both chambers are hydraulically connected by a passage. In this passage, a pair of electrodes is arranged, which is coupled to a voltage source controlled in dependence on the engine vibration. Depending on the voltage at this pair of electrodes, an electric field builds up, which affects the viscosity of the electrorheological fluid in the passage. During operation, the housing is deformed on one side under load, so that liquid is displaced from one chamber through the passage into the other chamber. If a voltage is applied to the electrode pair during this phase, the viscosity of the liquid increases. The fluid then converts energy into heat, which dampens the movement of the engine. The passage with the electrode pair acts in this arrangement as a controllable valve.

such Motor bearings are quite suitable, highly sensitive to vibrations to react and to dampen them. Its field of application is due to the basic structure with However, flexible membranes limited. The membrane materials known today namely react very sensitive to unfavorable Temperatures and chemical environmental influences: They tend to be premature Aging and embrittlement. Still likely the use of such belt tensioner to small vibration frequencies and relatively large Vibration amplitudes may be limited because the membranes used usually have a high inherent rigidity.

Spanner-damping elements with an electrorheological damper are also made, for example DE 41 34 354 A1 known. In belt tensioners of this type, the aforementioned physical property of electrorheological fluids is used which abruptly change their viscosity as a function of an applied electric field.

at this vibration damper for a belt tensioner is in a housing a damping element coupled to a vibration exciter so arranged and in electrorheological fluid immersed, that in a motion alone the shape and the frictional resistance are effective. Split and Displacement currents are avoided. A pair of electrodes with one in dependence controlled by the movement of the vibrator voltage source is connected, is arranged so that the damping element at least partially lies in the field generated by the electrodes. When requesting a Increased voltage at the electrodes the toughness the electrorheological fluid in the electric field and thus the frictional resistance of the damping element. At the Switching off the voltage, the movement of the damping element is almost frictionless. By corresponding circuits of the voltage source can oscillate the vibration exciter directionally muted become.

The present invention includes belt tensioners as shown in the DE 41 34 354 A1 are disclosed.

A disadvantage of the prior art, that with a hydraulic tensioning element with the hydraulic oil, the damping also changes as a function of the temperature and over the service life. It is also unfavorable that the damping does not respond to the changing depending on the operating condition of the engine dynamic suggestions.

at Applications of known tensioner damper elements are in the selection of viscous liquids to take into account the prevailing operating temperatures. So far were only liquids with temperature ranges of e.g. -10 ° C to + 70 ° C available, which is a severely debilitating Criterion for their application under the known conditions in a motor vehicle engine room has been.

The Disadvantages of the prior art indicate that the temperature resistance the viscosity changeable liquid strong for the suitability or unsuitability of the same in tensioner damping elements for belt drives of internal combustion engines. In case of unavailability of a corresponding Liquid can the damping principle for one Application to internal combustion engines can not be realized.

Task of invention

Of the Invention has for its object to provide a belt tensioner, which in a wide range of applications and at different Operating conditions is applicable.

The solution This object is apparent from the features of claim 1 while advantageous embodiments and developments of the invention the dependent claims are removable.

Summary the invention

Of the The invention is based on the finding that magnetorheological liquids in terms of their properties, a temperature resistance over a huge Have temperature range.

The Invention is according to the features of Main claim therefore from a belt tensioner, especially for tensioner-damping elements for traction means in internal combustion engines, consisting of a sealed to the environment and with a viscosity modifiable liquid filled Casing, one movably arranged therein, with a vibration exciter coupled damping element, which is arranged so that when moving a flow of change their viscosity liquid causes, as well as with one with a function of the state of motion of damping element regulated voltage source coupled activation pair to produce a the viscosity the viscosity changeable liquid controlling stimulus.

moreover is according to the invention provided that the viscosity changeable liquid a magnetorheological liquid with high temperature resistance is.

By This structure is advantageously achieved that such a belt tensioner in a wide range of applications and under different operating conditions applicable, reliable works and guarantees easy production. This will be the application such tensioner damping elements for belt drive systems of internal combustion engines at all only possible.

In addition, can be provided that the viscosity of the magnetorheological Liquid through the suggestion about Electromagnetic fields can be influenced.

In an advantageous embodiment is the use temperature range the magnetorheological fluid preferably in the range of -40 ° C to + 130 ° C.

In Another development is the magnetorheological fluid with a voltage of preferably in the range of 2V to 24V and a current of preferably in the range of 1A to 2A controllable. This allows the magnetorheological fluid with the usual in vehicles electrical on-board voltage are controlled.

In a further advantageous embodiment of the invention is a Adjustment of viscosity the magnetorheological fluid via steer-by-wire, So about about an in-vehicle data bus system (e.g., CAN bus) with in a vehicle control integrated.

In another expression The invention is a not completely excluded temperature-dependent and age-related change the viscosity the liquid Compensated by a compensation device.

In In a further advantageous embodiment, the tensioner damping element is such trained that in belt drives or chain drives of internal combustion engines is applicable as part of a belt tensioning system or chain tensioning system. It can be provided that the tensioner for linear or rotary acting Clamping elements is used.

In another development is the Rie menspanner designed for targeted and active influencing of vibrations in the belt drive and / or influencing the noise behavior of the traction device. For example, the belt bias voltage can be reduced, which results in longer belt life and provides greater reliability.

So far here the terms belt tensioner or belt were used, should these also comprise tensioning devices with other belting means, the according to the characteristics of the invention are formed. Such is a tensioning device according to the invention also for a chain drive or other traction drives trained and with Advantage usable, which is why such embodiments by this invention are included.

Short description of drawings

The The invention will be described below with reference to the accompanying drawings some embodiments explained in more detail. In this shows

1 a longitudinal section through a tensioner-damping element for traction means with integrated belt tensioner,

2 a cross section along line II-II through the tensioner-damping element in 1 and

3 a longitudinal section through another belt tensioner.

detailed Description of the drawings

1 shows a tensioner damping element 1 for traction means such as belts, chains or the like in internal combustion engines with an integrated damping element of a belt tensioner 2 , The tensioner damping element 1 consists of a clamping element 3 that by a spring 4 in the sense of increasing the tension of the traction means, here a belt 5 , is biased.

The tensioning element 3 is in this embodiment as a clamping arm 6 formed, at its one free end a role 7 is arranged rotatably mounted and with its outer periphery to a belt 5 is applied. The tension arm 6 is at the other end with a wave 8th connected, rotatable by means of bearings 9 in a housing 10 is stored. In the case 10 is a trained as a spiral spring spring 4 arranged and supported so that the clamping arm 6 is biased accordingly.

The housing 10 is substantially hollow cylindrical and at its axial ends by a bottom 11 or a lid 12 closed and through the shaft 8th surrounding seals 13 sealed. The interior of the housing 10 is completely filled with magnetorheological fluid.

With the wave 8th rotatably connected and arranged at right angles to the shaft axis are two damping elements 15 arranged at an axial distance from each other. Between the two damping elements 15 and parallel to these is a housing-fixed, also formed as a disk activation 16 arranged. This activation 16 stimulates the viscosity of the magnetorheological fluid via electromagnetic fields. The activation 16 is by means of insulation 17 opposite the housing 10 electrically isolated.

The damping elements 15 themselves are electrically conductive and are used directly as activation. The damping elements 15 and the activation 16 are electrical with the voltage source 19 connected. The applied voltage is dependent on the movement of the clamping element 3 via the control displayed as a black box 20 regulated.

In 2 is a cross section of the tensioner damping element after 1 represented according to the arrows entered there II. It can be seen in 2 in that the damping element 15 is formed as a segment-shaped disc, which in the axial direction also formed as a segment-shaped disk activation 16 partially covered. The damping elements 15 and the activation 16 are arranged in said circuit and form a capacitor whose capacity depends on their coverage in the axial direction. Upon rotation of the damping elements 15 the capacitance change of this capacitor can be detected. This capacitance change is a measure of the movement of the clamping element 3 and thus can by means of the controller 20 for controlling the voltage source 19 or the voltage applied to the activations are processed.

The controller works in this tensioner damping element 1 so that in the operating phases, in which the tension in the belt 5 increased by the drive, an electromagnetic field between the damping elements 15 and activation 16 built so that the electrorheological fluid located there increases its toughness, with the result that the frictional resistance of the damping elements 15 in the liquid magnification ßert. The by the increase in tension of the belt 5 generated movement of the clamping arm 6 is thus effectively damped. In the opposite case, with tension lock in Rie men, becomes the voltage source 19 switched off, which degrades the electromagnetic field between the activations, the friction of the damping elements 15 in the magnetorheological fluid decreases and the tension arm 6 over the spring 4 undamped the belt can be tracked.

3 shows a longitudinal section of another embodiment of a damping element of a belt tensioner 2 , In a hollow cylindrical housing 21 , which at both axial ends by a ground 22 or a cover plate 23 is closed, is a damping element 24 , which with a the housing 21 penetrating piston rod 25 is connected, guided longitudinally displaceable. The tour takes place via the bearings 26 the piston rod 25 , The piston rod 25 is with a clamping arm, not shown here 6 a belt tensioning and damping device connectable.

The damping element 24 is executed as activation; a second hollow cylindrical electrode 27 is on the inner circumferential surface 28 of the housing 21 arranged. The damping element 24 and the electrode 27 are with one in response to the movement of the damping element 24 controlled voltage source 29 connected. When applying a voltage to the activations arises between the outer periphery of the damping element 24 and the inner circumference of the activation 28 an electromagnetic field. Because the inside of the case 21 is completely filled with magnetorheological fluid, then increases the toughness of the magnetorheological fluid in the field of activations. The frictional resistance of the damping element 25 increases in size and its movement is subdued. To reduce the shape resistance of the damping element 24 are in this axial through holes 30 intended.

1

Tensioner damping element

2

damping element a belt tensioner

3

clamping element

4

feather

5

belt

6

clamping arm

7

role

8th

wave

9

camp

10

casing

11

ground

12

cover

13

poetry

14

inner space

15

damping element

16

activation

17

insulation

18

circlip

19

voltage source

20

control

21

casing

22

ground

23

cover plate

24

damping element

25

piston rod

26

camp

27

hollow cylindrical activation

28

Inner surface area

29

voltage source

30

Through Hole

Claims (9)

Belt tensioner, in particular for tensioner damping elements ( 1 ) for traction means ( 5 ) in internal combustion engines, consisting of a sealed to the environment with a viscosity-changeable liquid filled housing ( 10 . 21 ), a movable therein arranged, coupled to a vibration exciter damping element ( 15 . 24 ), which is arranged such that it causes a flow of the viscosity-changeable liquid during a movement, as well as one with a function of the movement state of the damping element ( 15 . 24 ) regulated voltage source ( 19 . 29 ) coupled activation pair ( 15 . 16 . 24 . 27 ) for generating a viscosity controlling the viscosity of its liquid viscosity-controlled excitation, characterized in that the viscosity-variable liquid is a magnetorheological fluid with high temperature resistance. Belt tensioner according to claim 1, characterized that the viscosity the magnetorheological fluid through the suggestion about Electromagnetic fields can be influenced. Belt tensioner according to one of claims 1 or 2, characterized in that the operating temperature range of magnetorheological fluid in the range of -40 ° C to + 130 ° C. Belt tensioner according to one of the preceding claims, characterized characterized in that the magnetorheological fluid with a voltage in the range of 2V to 24V and a current in the range of 1A to 2A is controllable. Belt tensioner according to one of the preceding claims, characterized characterized in that a viscosity adjustment of the magnetorheological fluid via steer-by-wire can be integrated with a vehicle control. Belt tensioner according to one of the preceding claims, characterized in that a temperature-dependent and aging-related change the viscosity can be compensated by means of a compensation device. Belt tensioner according to one of the preceding claims, characterized in that the tensioner damping element ( 1 ) is applicable in belt drives or chain drives of internal combustion engines as part of a belt tensioning system or chain tensioning system. Belt tensioner according to one of the preceding claims Application for linear or rotary acting clamping elements. Belt tensioner according to one of the preceding claims for the purposeful and active influencing of vibrations and / or noise behavior of the traction means ( 5 ).