DE102013214449A1 - Mechanical chain tensioner with bayonet lock - Google Patents

Abstract

The invention relates to a mechanical tensioner (1) for a traction mechanism drive of a motor vehicle, comprising a housing (2) on which a tensioner lever (11) is rotatably mounted via a bayonet closure, wherein a spring (12) causes the tensioner lever (11) to be triggered biased by a pivoting or rotating movement, wherein the bayonet closure is formed by the interaction of at least one radially protruding tab (7) on a bolt (8) with a Hintergrifffläche (6) on the housing (2), wherein at the Hintergrifffläche (6 ) is a protruding from her and in the direction of the tab (7) extending survey (13). The invention also relates to a traction mechanism drive with such a tensioner.

Description

Field of the invention

The invention relates to a mechanical tensioner / a mechanical tensioning device for a traction mechanism drive of a motor vehicle, as used in cars, trucks or other commercial vehicles, with a housing on which secured via a bayonet lock a tensioner / clamping arm is rotatably mounted, wherein a spring Clamping lever biased to cause a pivoting or rotating movement, wherein the bayonet closure is formed by the interaction of at least one radially projecting tab on a bolt with a Hintergrifffläche on the housing.

Traction drives and tensioning devices for traction drives in motor vehicles are already known from the prior art, for example from the DE 10 2009 032 557 A1 ,

Usually, belts or chains are used in traction mechanism drives to transfer torque from at least one crankshaft to at least one output shaft, such as a camshaft and / or one or more shafts of one or more accessories.

It must be ensured that the traction device always remains tensioned, which is why tensioners are used.

Usually, mechanical or hydraulic tensioners are used, the mechanical tensioner advantages in terms of cost and weight u. a. entail.

Such a mechanical tensioner is, for example, also from the DE 10 2011 080 509 A1 known. There, a belt tensioner is disclosed comprising a base member and a tensioning arm rotatably mounted thereon with a tensioner pulley, the pivot bearing comprising a pivot pin fixed at one end to a bore of the base member or the tensioner arm and provided with a collar at the other end against which an end face of the clamping arm or of the base part starts axially in order to support axial forces of a torsion spring bracing the clamping arm against the base part. It is there found to be particularly particular that the federal government is formed integrally with the axle and the attachment of the axle bolt is formed positively acting at one end in the manner of a bayonet closure.

In this earlier patent application is also disclosed that the bayonet lock comprises: two projections which are diametrically arranged on the circumference of the axle, two longitudinal grooves which are arranged and formed in the bore of the base part or the clamping arm so that the projections of the axle pin can be inserted through the hole, and two recesses, which are arranged on the front side at the mouth of the bore and in which the projections are held in a form-fitting manner. It is further disclosed that the longitudinal grooves and the recesses are arranged alternately and radially offset by 90 ° to each other.

It should be noted that the mechanically biased Zugmittelspanner is universally applicable, but in particular is designed for use in internal combustion engines.

It serves in combination with a correspondingly designed clamping rail to ensure the synchronization between a camshaft or more camshafts and a crankshaft, characterized in that there is always at least the minimum required chain tension at the respective speed.

By means of the chain tensioner also possible vibrations in the traction means should be damped, with a wear-related elongation is to be compensated as a chain.

The advantage of a mechanical tensioner is u. a. also in that the installation on the engine can be completely independent of a supply oil circuit. This avoids hydraulic losses, relieves the oil pump and does not require a throttling back valve.

It is the object of the present invention to eliminate the disadvantages of the prior art and to provide a robust and inexpensive tensioner.

Disclosure of the invention

This object is achieved in a generic tensioner according to the invention in that there is a projecting from her and extending in the direction of the tab elevation on the Hintergrifffläche / undercut surface. The tab must then, after the bolt is inserted and is rotated in a securing direction, pass over this survey, whereby the friction between the tab and the housing is considerably increased. A safer tensioner is the consequence, which does not dissolve again even with strong vibrations and vibrations.

Advantageous embodiments are claimed in the subclaims and are explained in more detail below.

Thus, it is advantageous if the survey is designed as a projection and / or as caulking. The projection may have a rounded shape, in particular have a spherical, convex or spherical section-like shape.

An advantageous embodiment is also characterized in that the survey in the locked, prepared for use state is positioned approximately in the middle of the tab.

Further, it is advantageous if the survey is so dimensioned, in particular such an axial height, that the bolt is clamped so axially that rotation of the bolt is difficult or prevented. An advantageous embodiment is also characterized in that an end stop on the housing is arranged so that a rotational movement of the bolt is prevented by the interaction of the at least one tab with the at least one end stop. Advantageously, two end stops and two tabs are used, just as two elevations are used. The elevations are approximately in the middle between the end stop and a recess for the tabs in the housing.

It is also advantageous if the end stop is formed as an input or output of the housing.

In order to further minimize costs, it has proven to be advantageous if the housing is plate-like, for example, as a deep-drawn sheet produced without cutting. With skillful choice of materials, a needs-based design can be achieved. Thus, it is advantageous if the tensioner lever is designed as a casting, for example as a plastic component.

The invention also relates to a traction mechanism drive with a mechanical tensioner according to the invention.

It is advantageous if the traction mechanism uses a trained as a chain traction means which is biased or biased by the force of the spring, such as using a tension roller which is rotatably connected to the tensioner lever.

In other words, a tensioner is presented, which biases a timing chain by means of a tensioning rail and thereby keeps the traction means under tension. The goal is achieved to achieve a minimal offset between the crankshaft and the camshaft. Furthermore, the biasing force of the tensioner is kept as constant as possible over the working area.

Should resonances occur at certain speeds of the internal combustion engine, this usually leads to a swinging of the chain. However, the vibrations of the traction means are damped by the outer and inner wheel contacts of the clamping system, whereby the function of the system is ensured.

The overall system is optimized in terms of manufacturing costs.

The tensioner is mounted using a bayonet catch. For this purpose, two strips or tabs and two corresponding slots are provided in the base plate on a bolt. The slots can also be referred to as recesses. The connection is made via a plug-in rotary movement. During installation, the bolt is inserted into the tensioner lever, the spring is preloaded axially and then the bolt is rotated with a turning tool by about 90 ° until the two elevations are reached. The bolt is turned over these surveys.

In this case, the respective elevation may adjoin a laterally projecting end face, that is to say be radially slightly further outward, or be radially further inward than the tab end and thus come to rest under the tab instead of bordering only on the end face of the tab.

When turning to elevations acting as end stops, the said elevation is swept or swept along it. There are two of these surveys to be swept, which are designed as Zweypunktverstemmung.

Due to the axial preload or the jamming caused by the Zweipunktverstemmung, a hedge against rotation of the bolt is achieved in the base plate.

An application of the mechanical tensioner together with a toothed belt tensioner is also conceivable. A very simple, robust and cost-effective way to mount a tensioner is thereby created.

The invention can also be developed for a traction drive of an internal combustion engine, with a base part which is fastened by means of a bearing pin on a motor surface, a rotatably mounted thereon clamping part, between the base part and the clamping part kraftbeaufschlagend arranged coil spring and a friction element, the coil spring circular arc surrounds and starts against the outer circumferential surface of the base part or the inner circumferential surface of the clamping part to the rotational movement of the clamping part to damp, wherein the clamping part is designed as a lever which has at its distal end a non-rotatable contact body, which is adapted to come to a clamping rail of a chain drive pressurizing to the plant.

It is possible that the base part has a cylindrical bearing journal which projects into a hollow pivot of the clamping part and that a sliding bush is arranged between the bearing journal and the pivot pin.

It is also possible that the sliding bushing and the hollow pivot pin are made conical and the sliding bush is fixed against rotation on the pivot pin.

It is expedient if an angle α is included between a central axis M of the sliding bush and an outer peripheral surface of the sliding bush, which is between 10 to 40 °. The outer surface of the sliding bushing may have a structure optimized with regard to the coefficient of friction.

Also, the contact body and designed as a lever clamping part can be made in one piece.

It is expedient if the base part and the clamping part have mutually corresponding bores which are provided for receiving a pin to secure by means of the pins, the prestressed relative to the base part clamping part in a mounting position.

The invention will be explained in more detail with the aid of a drawing. In this case, a special embodiment is described in detail.

Show it:

1 and 2 a longitudinal section through a tensioner according to the invention in the assembled state,

3 and 4 a perspective view of the chain tensioner of 1 and 2 .

5 and 6 a perspective view of the bolt of the bayonet closure, as used in the embodiment of the invention,

7 a perspective view of the bolt from the other side than in the 5 and 6 shown,

8th a perspective view of only formed as a base plate housing with a receptacle for the bolt in the context of the bayonet closure,

9 a singular representation only of the tensioner lever, in a perspective representation, and

10 a representation of the mechanical chain tensioner in a view from below.

The figures are merely schematic in nature and are only for the understanding of the invention. The same elements are given the same reference numerals.

In the 1 and 2 is a first embodiment of a tensioner according to the invention 1 shown. This tensioner 1 can also be referred to as a clamping device. The tensioner 1 is used in a traction drive of a motor vehicle, in particular on an internal combustion engine. The tensioner 1 has a housing 2 on that as a plate 3 , Is designed in particular as a non-cutting deep-drawn sheet metal. In the case 2 is a hole 4 , in particular the 8th good to be found included.

The hole 8th has two radially outer recesses 5 on. The recesses 5 are in a backgrip area 6 introduced to allow radially projecting tabs 7 a bolt 8th that as a hollow bolt 9 is formed, can be used. The bolt 8th has a covenant at one end 10 on the other end exactly two tabs 7 , The bolt 8th stuck in a tensioner lever / clamping arm 11 that's about a feather 12 is deflected. The feather 12 forces a rotary movement of the tensioner lever 11 ,

As in the 3 and 4 It is easy to see is the area of the federal government 10 of the bolt 8th adapted to receive a tool, such as an Allen key. The tensioner lever 11 is made of plastic, whereas the plate 3 made of sheet metal.

While in the 5 to 7 the bolt is shown singularly is in 8th the plate 3 presented singularly. There are two friction-increasing surveys 13 used, which are designed in the manner of caulking in the range of Verstemmbereichen on the type of two-point stemming. Also are two end stops 14 formed, which are radially located further inside.

It is also possible that the surveys 13 so far out, in the radial direction, they are the tabs 7 touch on its radial outside and increase the friction there.

The interaction of the tabs 7 , the surveys 13 and the end stops 14 is in 10 well depicted. The bolt 8th is in the axial direction been moved so that the tabs 7 through the individual recesses 5 were passed through and then due to a rotation counterclockwise on the Hintergriffflächen 6 been turned. Stop sides of the tabs 7 denoted by the reference numeral 15 are marked, then arrive in abutment with an end stop 14 , The tab 7 is also in contact with a frictional force causing elevation 13 ,

LIST OF REFERENCE NUMBERS

1

Stretcher

2

casing

3

plate

4

hole

5

recess

6

Back-engagement surface

7

flap

8th

bolt

9

hollow pin

10

Federation

11

Release lever / tensioning arm

12

feather

13

survey

14

end stop

15

Side of the tab

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 102009032557 A1 [0002]
• DE 102011080509 A1 [0006]

Claims (4)

Mechanical tensioner ( 1 ) for a traction mechanism drive of a motor vehicle, with a housing ( 2 ), to which secured by a bayonet lock a tensioner lever ( 11 ) is rotatably mounted, wherein a spring ( 12 ) the tensioner lever ( 11 ) biased to cause a pivoting or rotating movement, wherein the bayonet closure by the interaction of at least one radially projecting tab ( 7 ) on a bolt ( 8th ) with a backgrip surface ( 6 ) on the housing ( 2 ) is formed, characterized in that at the Hintergrifffläche ( 6 ) one protruding from her and in the direction of the tab ( 7 ) survey ( 13 ) is located. Stretcher ( 1 ) according to claim 1, characterized in that the survey ( 13 ) is formed as a projection and / or caulking. Traction drive with a mechanical tensioner ( 1 ) according to any one of the preceding claims. Traction drive according to claim 9, wherein a trained as a chain traction means by the force of the spring ( 12 ) is biased or biased, for example by using a tensioning roller, the tensioner lever ( 11 ) is rotatably connected.

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