Traction means such as belt or chain, in particular for a traction mechanism of a
Internal combustion engine
The invention relates to a tensioning device for a traction means such as belts
or chain, especially for
a traction drive of an internal combustion engine, comprising a base part,
which is fixed to a third object, and a
with the base part over
a plain bearing rotatably connected clamping arm, which is against the restoring force
a spring element with respect
of the base part is rotatable, and with a between the base part
and the tension arm arranged friction element for damping the lever movement.
Automotive used internal combustion engines usually have
a traction mechanism on, with the auxiliary equipment such as the
Water pump, the generator, the fan for the recooling of the coolant or the compressor for the air conditioning
are driven. Usually
Such aggregates are by means of a traction mechanism, the one
Endless belt includes, driven, the traction means on the individual
Pulleys of the units and one at the of the internal combustion engine
driven crankshaft arranged pulley is guided over which
Pulley of the drive is done. To achieve the best possible
slip-free To drive the aggregates and to achieve a high
Lifetime of the traction device is a defined Zugmittelspannung
required. For this purpose it is known to provide a tensioning device,
with the acted upon by a spring tension arm over a
Tensioner roller is supported on the traction means.
The functionality of the traction mechanism drive is not least influenced by the damping of the complete clamping system. As a result inevitably given rotational irregularities of the internal combustion engine and a usually discontinuous power consumption of integrated units in the train (not every unit is continuously turned on or off), it usually comes to a jerky, pulsed load of the traction mechanism and all arranged in the traction drive bearing points. Such undamped stresses reduce the life of the traction device. To counteract this, it is for example off DE 100 21 708 A1
known to integrate a damping device with a rotational direction-dependent friction effect in a clamping device. For this purpose, a friction element or friction lining is arranged between clamping arm and base part, wherein the base part and the clamping arm bear frictionally against the friction element or friction lining. About this movement coupling can be counteracted the traction stressing impulsive, pulse-like loads.
there is always an effort to reduce the damping characteristics of the
Speech clamping devices to improve, as well as the endeavor
to simplify the construction of a clamping device to the cost price
to reduce the clamping device. So usually there is the base part
known clamping devices of several parts, namely the
one of a base plate, over
which fixed the clamping device, for example, on the engine block
is, a central bolt which rotatably connected to the base plate
is, and the friction disc, which is attached to the bolt, wherein the
made of solid material, if the fixation of the clamping device,
For example, on the engine block, done alone on the base plate,
or a central aperture for receiving a fastening screw
having. This makes the tensioner not only of the basic construction
agile and therefore expensive, it is also difficult, what increasingly
The invention is thus based on the problem, a simple design
Specify clamping device, which also in terms of damping properties
This problem is in a clamping device of the aforementioned
Art provided according to the invention,
that the base part consists of a base plate and a friction disc pressed with this
consists, wherein the sliding bearing on pointing to the base plate end
the clamping lever hub is arranged, and that between the edge side
Friction disc and one of the spring element against the friction disc
pressed clamping lever
provided pot-like Reibscheibenaufnahme the axial and radial
acting friction lining is arranged.
The base part in the clamping device according to the invention consists only of two components which are pressed together, namely the base plate or the base plate component and the friction disc or friction disc component pressed therewith. These two elements, namely base plate and Friction disc or base plate member and friction disc component are designed according to a particularly advantageous embodiment of the invention as sheet metal or extruded sheet metal parts, wherein on the base plate, the friction disc or both a cylindrical connecting lug is formed over the or both of which are pressed together. So extremely simple designed parts are used, so that can be dispensed with the elaborate design of the base part using partially made of solid material components.
Provided according to the invention
is also the use of an axially and radially acting friction lining,
this forms a combined axial-radial friction bearing.
Therefore, provided in this area radial sliding bearing can
be waived. For this purpose, the friction disc is designed angled, the
she is cranked at the edge,
so that both an axial and a radial contact section
gives to the friction lining. On the tension lever in turn is a pot-like
Friction disc recording provided, which is also configured so
in that an axial and a radial contact section for the friction lining
results. Unlike known clamping devices is
in the tensioning device according to the invention
So the axial as well as radial Reiblagerpunkt radially seen
Diameters, compared to the usual small diameters
the axial friction linings,
as they were previously used. The increase in the friction radius of the friction
or sliding bearing brings a considerable increase in the frictional resistance
itself, giving the damping force
can be. The combination of axial and radial friction bearing
bring it over it
also entails using only one friction element or friction lining
must be, but not several separate coverings, as is often the case
The state of the art is the case.
All in all
results in particular in execution of the base plate and the
Friction disc as a simple sheet metal part a very simply designed clamping device
with excellent damping properties.
In a first embodiment of the invention, it is possible to
the friction disc and the cup-like friction disc holder in the plant area
to the friction lining angled at an angle between 75 ° -110 °, preferably
of substantially 90 °. The
Friction disc as well as the cup-like Reibscheibenaufnahme, in the
the friction disc is received, so - with respect to the lever rotation axis - a
perpendicular to the axis of rotation stationary contact section on the
the axial Reiblagerung takes place, as well as an axis-parallel section, over the
the radial friction bearing is realized.
For this embodiment, it is conceivable that the friction disc in the
Investment area to the friction lining has a cone section, while the
cup - shaped friction disc holder in the contact area to the friction lining angled in
an angle between 75 ° -110 °, preferably
of 90 °.
In this embodiment, in which preferably a slotted or
segmented friction element or friction lining is used over the
Angled extending cone section an expansion of the friction element
realized, that is, this
is due to the bias of the clamping lever against the friction disc
deformed and outward
As a result, the radial and axial contact of the friction lining to
cup-shaped pulley recording even further improved.
another alternative of the invention, on the other hand, provides that both the friction disk
as well as the cup-like Reibscheibenaufnahme in the plant area for
Have friction lining a cone section. Here too is due
the axial spring biasing force realized a widening of the friction lining.
the two cone sections on the friction disc and the pot-like
Friction disc mount substantially parallel to each other,
alternatively you can
they also diverge radially. As a result of the conical
Profiling also friction disc holder in the edge area also carries
These contribute to the radial expansion of the friction lining.
Friction lining itself is preferably provided a circumferential sealing element,
the one piece
can be with the friction lining, so from the same material as this
is, but alternatively in a two-component injection molding process
can be molded from a different material. As materials
Friction lining or the sealing element can all known materials
can be used, e.g. PA46PTFE15 or when forming the friction lining
from a multi-material layer system suitable recyclables such as Permaglide
or similar. By appropriate choice of material, the coefficient of friction
to further increase
the damping forces accordingly
Advantages, features and details of the invention will become apparent
the following description of the embodiments. Showing:
1 a schematic representation of an invent According to the invention tensioning device of a first embodiment,
2 a partial view of the combined axial-radial friction bearing between clamping lever and friction disc with a sealing element having a friction element,
3 a view corresponding to the 2 with a friction surface having a conical surface,
4 a view according to 2 with conical surfaces on the friction disc and the friction disc holder,
5 a view accordingly 2 with a further embodiment of a usable friction disk and
6 a view accordingly 2 with conical surfaces provided on the friction disc and the friction disc receiver, which run apart.
Description of the drawings
1 shows a clamping device according to the invention 1 , consisting of a base part 2 that made of a base plate 3 (or base plate part) and a friction disc 4 (or friction disc part). The base plate 3 and the friction disc 4 are formed as one-piece produced in a drawing or an extrusion molding Blechumformteile. The base plate 3 has on the one hand the plate-shaped foot 5 on to which a cylindrical connecting lug 6 is formed. The friction disc 4 also has a cylindrical connection approach 7 on. About the two approaches 6 . 7 are the base plate 3 and the friction disc 4 pressed together, what the connection approach 7 a corresponding recording 8th is provided at the beginning.
Shown is also the tensioning lever 9 that with its cockle hub 10 the two approaches 6 . 7 embraces. At his to the base plate 3 pointing Na-end is a plain bearing 11 Pressed over the clamping lever 9 with respect to the base part 2 or here the base plate 3 is mounted radially.
The tension lever 9 is against the restoring force of a spring element 12 , here a coil spring, with respect to the base part 2 rotatable. The coil spring 12 is at one end to the base plate 3 established. At the other end is the coil spring on the clamping lever 9 arranged. Provided that the spring fixing serving spring ramp on the base plate 3 can not be formed, it is conceivable, a separate plastic part with incorporated spring ramp on the base plate 3 to arrange.
While the cocking lever 9 at one end over the slide bearing 11 is guided and supported, it is at the other end via a combined axial-radial bearing, which also provides the damping for the system stored. For this purpose, the friction disc 4 at the edge angled. She is in one of the clamping lever 9 trained pot-like friction disk holder 13 added. In the mounting position is located between the here substantially 90 ° angled friction disc 4 and designed according to the shaping friction disc 13 A gap 14 in which a friction element 15 or friction lining is arranged. About this takes place both the axial and the radial bearing or damping.
The tension lever 9 is via the coil spring 12 from below against the friction disc 4 biased. The friction disc 4 has a radial contact surface 16 on, on the friction lining 15 is applied. Accordingly, the Reibscheibenaufnahme a radial contact surface 17 on. This is the axial storage or damping.
Due to the corresponding angled configuration, the friction disc 4 further an axial abutment portion 18 on, also the Reibscheibenaufnahme 13 has an axial abutment section 19 on, between which the axial section of the friction element 15 located. Obviously, therefore, a combined axial-radial friction or damping bearing is realized.
Not only the structure of the clamping device according to the invention 1 is easy, but also the assembly. This is on the base plate 3 first the coil spring 12 to put, after which the lever hub 10 together with the pressed plain bearing 11 is plugged. Subsequently, the friction lining 15 used, after which the friction disc 4 plugged in and with the base plate 3 is pressed.
The large radius in the area of the friction element 15 offers maximum damping for the traction drive, which is no longer shown. In the embodiment according to the invention also any tilting moments as a result of axially seen relatively widely spaced bearing points, realized via the sliding bearing 11 and the axial-radial bearing via the friction element 15 , minimized. The reduction of the tilting moments is also beneficial to the fact that the storage on the friction element is very far outside and in approximately direct extension of the not shown in detail, located on the clamping lever tensioner or clamping rail.
2 shows in an enlarged view the bearing area between friction disc 4 and friction disc holder 13 , The embodiment corresponds to in 1 described, however, is on the friction element 15 a sealing element 20 molded, the friction disc recording 13 seals off. In this embodiment, the friction element 15 via not shown in detail driver in the form of a toothing or the like with the friction disc 4 connected, so the sliding surfaces are located on the Reibscheibenaufnahme. Of course, a reverse configuration is conceivable, that is, it is possible, the friction element 15 at the friction disc holder 13 to fix, the friction surfaces would then be on the contact surface of the friction disc 4 to the friction element 15 ,
3 shows an embodiment in which at the friction disc 4 a cone section 21 is provided. About this conical section is the friction element 15 , which is made significantly stronger here, in combination with the axial spring biasing force radially expanded and thus when fixing the friction element 15 at the friction disc 4 against the contact surfaces 17 and 19 the Reibscheibenaufnahme 13 pressed. As a result, the damping can be increased. The damping is thus on the one hand by the axially on the friction element, which acts as an axial thrust washer in the axial direction and intercepts the axially acting force component of the coil spring generated, as well as by the radially caused by the cone radial forces. To an expansion of the friction element 15 To simplify, it is advisable to use this in a multiple slotted or segmented design.
4 shows an embodiment in which both the friction disc 4 as well as the friction disc holder 13 parallel cone sections 21 . 22 are provided. In this embodiment, there is likewise a radial widening of the friction element 15 but not only by a conical surface as in the embodiment according to 3 is generated, but by the two cooperating conical surfaces.
In the embodiment according to 5 is on the base plate, not shown, a complete Spannhebelnabe 10 of the clamping lever 9 penetrating cylindrical connection approach 6 formed, on which the friction disc 4 is pressed on. The friction disc 4 also here has a cone section at its edge region 21 on, over which the friction element 15 in the friction disk holder 13 and there against the axial and radial contact surfaces 17 and 19 pressed and widened. Unlike the design after 3 is at the friction disk 4 at the edge another bend 23 provided, which is the cup-like Reibscheibenaufnahme 13 largely closes towards the outside, so that a sealing element on the friction element 15 can be waived.
6 finally shows an execution similar 5 However, here is in addition to the friction disc surface instead of the plane-parallel, axially effective start-up or contact surface 17 another cone section 24 provided, wherein the two cone sections 21 at the thrust washer 4 and 24 at the friction disc holder 13 diverge radially outward. The cone section 24 also contributes to the expansion of the friction element as a result of the spring preload 15 and thus to increase the contact force at the plant sections 17 and 19 at the friction disc holder 13 at.
- tensioning device
- connecting shoulder
- connecting shoulder
- clamping lever
- spring element
- contact surface
- contact surface
- contact section
- contact section
- sealing element
- cone section
- cone section
- cone section