CN104819256B - Tensioning device for a traction mechanism drive - Google Patents

Abstract

The invention relates to a tensioning device for a traction mechanism drive, which has a pivot pin (1) fastened thereto for pivotable mounting of a tensioning rail, at least one leaf spring (6) and a tensioning rail (3) for pretensioning the traction mechanism (5), which has a bearing hole (2) for accommodating the swivel bolt (1) and a hole for accommodating at least one leaf spring (6) A channel (9) comprising an end piece (13) with an abutment side (15), an opposite upper side (14) and a rear end (16), wherein the end of at least one leaf spring (6) The part ( 13 ) is curved and cooperates with an abutment element ( 12 ) mounted on the tensioning rail ( 3 ) through an at least partial positive fit.

Description

Tensioner for traction drive

technical field

The invention relates to a tensioning device for a traction mechanism of a traction mechanism drive, which has a pivot pin fixed thereon for pivotable mounting of a tensioning rail, at least one leaf spring and a Tensioning rail of a pretensioning traction mechanism, the tensioning rail has a bearing hole for accommodating a swivel bolt and a channel for accommodating at least one leaf spring, which comprises a bearing side, an opposite upper side and a rear The end piece of the end part.

Background technique

The field of application of the invention extends in particular to internal combustion engines in which a traction drive is used. Such traction mechanism transmissions are often used to transmit the torque of a first shaft to a second shaft. In this case, a toothed wheel is attached to the first shaft, which drives a traction mechanism, such as a belt or a chain, via a non-positive or form-fit connection. The same traction mechanism is likewise in non-positive or form-fit engagement with the gear wheel mounted on the second shaft, thereby driving it. For efficient and low-wear operation, it is desirable here that the traction means be kept tensioned in order, for example, to avoid vibrations of the traction means perpendicular to the direction of travel. Furthermore, manufacturing tolerances in the length of the traction means and extensions of the traction means through use are compensated for in this way.

For this purpose, in the generally known state of the art, a tensioning rail is used which has an outwardly curved sliding surface and cooperates with a pressing mechanism which presses the tensioning rail against the traction means and thus tensions the traction means . Typically, torsion springs or leaf springs are used, for example, as the pressing mechanism.

DE 10 2004 014 486 B4 discloses a tensioning device with a torsion spring. What is problematic here is that the forces generated by the cooperation of the torsion spring and the tension mechanism act on one side on the base body supporting the torsion spring. Such one-sided mechanical loading can lead to disadvantages, for example in the form of twisting or tilting of the system of base body and tensioning rail.

This problem can be avoided by using a leaf spring which is placed on at least two abutment elements of the tensioning rail which are spaced apart from one another and cooperates with pins fastened to the internal combustion engine. Here, the force loading occurs symmetrically, but the problem arises of securing the leaf spring so that it does not slip off and, for example, does not damage the tensioning rail with sharp edges or loses contact with the contact element. A torsion spring can simply be fixed in its helix by means of pins, whereas a fixation against movement in the longitudinal direction, transverse direction or force direction of the leaf spring is more important.

A solution for fastening leaf springs is shown in DE 20 2007 005 472 U1. There, the leaf spring is perforated at one end to receive a pin, by means of which the leaf spring is fastened and surrounded at the other end by a form-fitting recess in the tensioning rail. However, such a device is expensive due to the need to drill holes for the leaf spring. Furthermore, such a device has a plurality of contact lines due to the enclosed pins and form-fitting recesses, at which contact lines the leaf spring is perpendicular to its An edge that is as sharp as possible extending in the longitudinal direction can cause damage to the pin and the recess of the tensioning rail. Such damage to the tensioning rail is particularly problematic since the tensioning rail is generally produced from a soft material, such as injection-molded plastic, whereas the leaf spring is generally produced from a hard material, such as a metal alloy. Furthermore, due to the fixed height of the pin and the recess it is not possible to additionally surround other leaf springs.

A further solution is disclosed in DE 10 2013 200 162 A1 in the form of a tension rail in which a U-shaped bent wire is guided as a spring. Due to the circular cross-section of the wire forming the spring, no wear occurs on the surround of the U-shaped end of the spring. However, due to the unusual shape of the springs, this implementation is complex to manufacture and also cannot use several springs simultaneously. Furthermore, it can be difficult to introduce the straight spring in the relaxed state into the curved channel provided for this purpose.

Contents of the invention

It is therefore the object of the present invention to provide a tensioning device which can accommodate more than one leaf spring in order to generate an adjustable pressing force and which hereby allows its edges and tensioning A small number of contact wires of the rail.

The invention includes the technical teaching that the end piece of at least one leaf spring is curved. For example, the end piece can be bent or bent on one or more mutually parallel fold lines to rest against the abutment element.

The advantage of the solution according to the invention is that, in particular, at least one leaf spring presses its bent end part against the abutment element in the tensioned state, so that in addition to static friction, the leaf spring also passes through the curved abutment surface Movement is prevented and the leaf spring is thus secured against slipping on the abutment element.

A measure improving the invention provides that the end part rests with its abutment side on the abutment element, so that the rear end protrudes beyond the abutment element. Thus, in particular a contact between the end piece and the abutment element is formed, wherein the abutment surface of the end piece only touches the abutment element, but not its edge extending perpendicularly to the longitudinal direction of the leaf spring. This prevents the tensioning rail, which may be made of soft material, from being worn, for example by scratching, chipping and cutting by sharp edges of the leaf springs.

Furthermore, the invention can also be developed in such a way that the abutment element is configured cylindrically, so that the abutment side formed by two mutually angled surfaces lies tangentially on the peripheral side of the cylinder, The line of intersection of the contact sides is directed parallel to the cylinder axis. It is particularly advantageous that the tensioning of the leaf spring allows its end part to be moved tangentially on the cylinder circumference, but also remains in contact with the abutment element at the same time and also by the direction of force of the leaf spring be stabilized. The end piece is preferably V-shaped, optionally with a rounded tip.

Furthermore, the invention can be developed in such a way that at least one leaf spring has a shape which allows a form-fitting placement of a structurally identical second leaf spring on the at least one leaf spring. This criterion applies in particular to the end pieces, since the leaf springs are designed essentially flat and straight apart from the end pieces. The channel in which at least one leaf spring is guided should at the same time be high enough to accommodate a plurality of such leaf springs. The advantage here is that several leaf springs can be used modularly, so that the pressing force of the tensioning rail against the traction mechanism can be adjusted without the tensioning rail itself having to be changed or removed.

In a preferred embodiment of the invention, the free space around the abutment element is surrounded by at least one guide hook, which prevents the end piece from falling out of the free space and which simultaneously enables the end piece to be moved manually. Dropping onto snap-on components is easy. In addition, if the end pieces of the leaf spring are wider than the outer wall, the at least one guide hook can be formed as a component of the outer wall, which can lead to simplified production and greater stability of the at least one guide hook.

In addition, the invention can be developed in such a way that a recess is provided in at least one outer wall of the tensioning rail, into which a locking pin can be inserted which can hold at least one leaf spring under tension. Thus, even outside the traction mechanism drive, the tensioning rails can be transported together with the tensioned leaf springs, so that they can then be mounted easily on the traction mechanism drive without having to tension the springs as well.

Description of drawings

Further measures improving the invention are given in the dependent claims or are shown in detail below together with the description of preferred exemplary embodiments of the invention with reference to the drawings. in:

1 shows a longitudinal section through a tensioning device according to the invention with three pretensioned leaf springs,

Figure 2 shows a detailed view of the position of the end pieces of the leaf spring, and

3 shows a perspective view of a tensioning rail according to the invention of the tensioning device with an inserted leaf spring.

Detailed ways

According to FIG. 1 , the tensioning device comprises a swivel pin 1 mounted on an internal combustion engine not shown further, which is inserted into a bearing hole 2 of a tensioning rail 3 , which can thus be pivoted around this swivel pin 1 support. The slide rail 4 of the tensioning rail 3 is in contact with a traction mechanism 5 of a traction mechanism drive (not shown further) and keeps it tensioned.

The force pressing tensioning rail 3 against traction means 5 is formed by the deflection of three leaf springs 6 , 7 , 8 which are tensioned in channels 9 in tensioning rail 3 in a form-fitting manner with one another. This tensioning is produced by the abutment of the leaf spring 6 on the pin 10 mounted on the internal combustion engine, the border 11 of the bearing hole 2 and the partly cylindrical abutment element 12, which is passed through the lower leaf spring 6 The curved end piece 13 of the 100 is surrounded by such that the leaf spring 6 and thus the form-fitting leaf springs 7 , 8 are secured against slipping.

In this exemplary embodiment, the end piece 13 has a v-shape with a rounded tip. The end piece comprises an upper side 14 , an abutment side 15 and a rear end 16 which is formed by edges and surfaces perpendicular to the longitudinal direction of the leaf spring 6 . In the tensioned and relaxed state of the leaf spring 6 and in every state between them, the rear end 16, especially its edge, does not come into contact with the tensioning rail 3, thus preventing material wear and tear. If the leaf spring 6 is tensioned or relaxed, only the tangentially positioned abutment side 15 slides on the peripheral side of the cylindrically configured abutment element 12 . The pressure of the leaf spring 6 and the v-shape of the end piece 13 simultaneously prevent it from slipping off the contact element 12 .

The recess 21 in the outer wall 18 allows the spring to be tensioned by means of a not shown locking pin guided therein, so that the tensioning rail with the tensioned spring can be stored or transported outside the traction mechanism drive.

It can be seen in particular in FIG. 2 that the rear end 16 of the leaf spring 6 is not in contact with the tensioning rail 3 in the relaxed state. In comparison with the tensioned state in FIG. 1 it can be seen that the rear end is not in contact with the tensioning rail 3 although it is close to the inner side.

FIG. 3 shows a perspective view of a tensioning rail 3 according to the invention. It can be seen here that the end piece 13 of the leaf spring 6 is wider than the channel 9 in which the leaf spring is guided. The free space 17 in which the end piece 13 rests on the contact element 12 is surrounded by an outer wall 18 and a guide hook 19 formed as part of the outer wall 18 . The wide end piece 13 of the leaf spring can be inserted easily through the narrow gap 20 between the guide hook 19 and the outer wall 18 , but prevents undesired removal. Even if the leaf spring 6 springs back suddenly, the guide hook 19 also plays a protective role and prevents the leaf spring 6 from leaving the tensioning rail 3 .

The invention is not limited to the previously described preferred embodiments. In particular, modifications included within the scope of protection of the following claims are also conceivable. Thus, for example, it can also be realized that at least one leaf spring rests on its two ends in the tensioning rail, so that the pin fixed on the traction mechanism transmission and the end that rests in the tensioning rail The intermediate parts between the parts cooperate in order to generate the tensioning of the leaf spring and thus the traction mechanism.

List of reference signs

1 turn pin

2 Support hole

3 tension rails

4 sliding surfaces

5 traction mechanism

6 leaf springs

7 Second leaf spring

8 Third leaf spring

9 channels

10 pins

11 Frame of support hole

12 Snapping components

13 End piece of leaf spring

14 Upper side of end piece

15 Adjacent side of end piece

16 Rear end of end piece

17 free space

18 outer wall

19 guide hook

20 gaps

21 recess

Claims (9)

1. a kind of tensioning apparatus of the traction mechanism (5) for traction mechanism drive, the tensioning apparatus include

The rotation bolt (1) for being used to be pivotally supported tensioning rail being fixed on the tensioning apparatus,

At least one leaf spring (6), at least one described leaf spring include having the side (15) that reclines, opposed upside (14) and rear knot The end pieces (13) in beam portion (16),

For pre-tightening the tensioning rail (3) of the traction mechanism (5), the tensioning rail has for accommodating rotation bolt (1) Supporting member hole (2) and channel (9) for accommodating at least one leaf spring (6),

It is characterized in that, the end pieces (13) of at least one leaf spring (6) construct deviously, and pass through at least part of shape Shape is sealed to act synergistically with the element that reclines (12) being mounted on the tensioning rail (3).

2. tensioning apparatus according to claim 1, which is characterized in that the end pieces (13) are sticked on its side that reclines (15) On the element that reclines (12), so that the rear end portion (16) of the end pieces protrudes beyond the element that reclines.

3. tensioning apparatus as described in claim 2, which is characterized in that the element that reclines (12) at least partially cylinder shape Construction, so that the side that reclines (15) being made of two faces at an angle to each other be made tangentially to be placed on cylinder week side with these faces On.

4. tensioning apparatus according to claim 1, which is characterized in that construct to end pieces (13) v-shaped.

5. tensioning apparatus according to claim 1, which is characterized in that multiple leaf springs (6) are arranged as spring assembly.

6. tensioning apparatus according to claim 4, which is characterized in that the channel (9) is configured for accommodating institute completely State at least one leaf spring (6).

7. tensioning apparatus according to claim 1, which is characterized in that around the free space (17) of the element that reclines (12) It is surrounded by least one guide hook (19).

8. tensioning apparatus according to claim 7, which is characterized in that the end pieces (13) of the leaf spring (6) are than the tensioning The spacing of the outer wall (18) of rail (3) wants wide, so that at least one described guide hook (19) is configured to the composition of the outer wall (18) Part.

9. tensioning apparatus as any one of preceding claims, which is characterized in that recess portion (21) is arranged in the tensioning In at least one outer wall (18) of rail (3), can be put into the recess portion makes at least one described leaf spring (6) keep tensioning Locking pin.