DE102017100801A1 - Timing belt tensioner for a timing drive with a slot for preloading - Google Patents

Abstract

The invention relates to a toothed belt tensioner (1) for a control drive of a motor vehicle, with a basic carrier (2) acting as a base, in which a slot (3) is present, and with a sliding ring (4) which is linearly movable relative to the base carrier (2) a tensioning roller (5) is rotatably arranged, wherein a linear spring for biasing a of the tension roller (5) contacted toothed belt is inserted and wherein in a tolerance balanced state, the position of the base support (2) via an inserted into the slot (3) fastener ( 6) is fixed.

Description

The invention relates to a toothed belt tensioner for a belt drive, such as a timing drive, a motor vehicle. The toothed belt tensioner is used to maintain a tension of a toothed belt, or generally a continuous drawing means. This is used to allow the control of the valves of an internal combustion engine. Thus, the rotational movement of the crankshaft is preferably transmitted via these toothed belt form-fitting manner to a camshaft.

In addition to the valve control, belt drives also perform a drive function for additional units, such as the generator, the coolant pump, the power steering pump or the air conditioning compressor. In such a case one speaks of aggregate drives.

Furthermore, also secondary drives, such as balancing shafts or oil pumps, are driven by the belt drive.

In order to enable a biasing position of the toothed belt tensioner, two concepts have prevailed. On the one hand, it is customary to bias the toothed belt tensioner by means of an eccentrically guided, linear translational movement, on the other hand, linearly guided displacements of the toothed belt tensioner also gain in importance.

Various toothed belt tensioners are known from the prior art. For example, the German patent application discloses DE 196 31 588 A1 a tensioning wheel for a traction means, wherein with a hollow shaft rotatably mounted on a tensioning wheel and arranged within the hollow shaft, by means of a spring element against the hollow axle spring-loaded, hollow piston element, a voltage of a continuous drawing means is achieved. Although that device is able to ensure a reliable voltage, but by means of the centrally arranged piston element, for example, no compensation of manufacturing tolerances can be realized.

At this point, the Japanese patent application JPH 11-132299 To remedy the situation. The Zugmittelspanner disclosed herein also has a spring mechanism which cuts the center of the tensioning wheel, that is arranged centrally. In order to at least partially compensate for manufacturing tolerances, the openings through which a fastener engages to set the Zugmittelspanner on an engine block designed as oval openings that allow a certain amount of play. In this way, the Zugmittelspanner takes up more space, which is generally to be avoided.

Also the generic Japanese patent application JPH 11-132298 finds no solution to the problem of too high space requirements.

Completing the state of the art is a brochure from Schaeffler Automotive Aftermarket GmbH & Co. KG dated September 2012. This is entitled Belt Drive Components - Technology, Damage Diagnosis and provides an overview of existing in the art toothed belt tensioner.

A disadvantage of the prior art is therefore that a tolerance compensation takes place over an enlarged working range of the clamping means. In addition to the installation space itself, this has a negative effect on the component stress and component wear.

Furthermore, the toothed belt tensioners of the prior art involve the risk of skipping teeth of the traction means as a result of the large tensioning path or clamping angle.

Furthermore, the prior art toothed belt tensioners are unable to maintain a constant angle between the force acting on the toothed belt tensioner from the toothed belt and the biasing force of the toothed belt tensioner. This leads to variations in the effective bias itself, which reduces the reliability of the toothed belt tensioner.

Even in such a case, in which an eccentric ensures the tolerance compensation of the toothed belt tensioner, the problems described above can not be remedied. Thus, in the case of an eccentric, the damping direction of the tensioning means tensioner is dependent on the eccentric angle.

Against the background of this prior art, the present invention has the object to develop a toothed belt tensioner, which, even if a tolerance compensation function is realized, causes no variation in the bias voltage. Furthermore, the object of the invention is to reveal a space-optimized and low-maintenance device.

This is inventively achieved in that the toothed belt tensioner has a base carrier acting as a base, in which a slot is present. Furthermore, the toothed belt tensioner on a sliding ring, which is linearly movable to the base body. On the sliding ring, which can also be referred to as a tension wheel carrier, a tension roller is rotatably arranged. A linear spring is used to bias a toothed belt contacted by the tension pulley, and in a tolerance balanced state, the position of the toothed belt is Base carrier fixed via a fastener inserted into the slot.

Thus, the compensation of the traction means is realized by a linear feed movement of the base support relative to the fastening element, which is preferably formed as a screw, and relative to the tensioning wheel against the force of the biasing spring.

The tolerance-compensated state is understood to be the state in which the base carrier, which is rigidly fixed to approximately the engine block, is fixed in such a way to the sliding ring that production-related and compensation-related tolerances are compensated.

In the following, advantageous embodiments are listed, all of which are encompassed by the inventive idea.

Advantageously, the displacement force, which is necessary for setting the toothed belt tensioner in the assembly, reduced by a translating lever. This allows a time-efficient and energy-saving installation. That lever, which can also be referred to as an assembly tool, is adapted to the geometry of the toothed belt tensioner so that a tightening of the tensioner is possible with one hand, so that the other hand can make the bias.

In particular, when the toothed belt tensioner has a setting mark for reading the tolerance-compensated state, the toothed belt tensioner is time-efficient and reliable mountable.

The toothed belt tensioner advantageously has an integrated torque support to prevent twisting of the tensioner during the tolerance compensation adjustment around the attachment sprocket.

Once a filler is arranged around the fastener to cause a centering, further advantages. The filler sits positively in the slot and avoids a relative rotation of the sliding ring to the body.

The toothed belt tensioner realizes its bias analogous to the prior art via a spring-damper mechanism, which consists of a spring, preferably a coil spring and a hydraulic damper.

In particular, when the effective direction of the spring-damper mechanism acts in the same direction regardless of the position of the fastener in the slot, the reliability of the toothed belt tensioner is increased.

Advantageously, the base body has a single slot for attachment to the engine block. This serves the space optimization. Furthermore, thus, the angle between the resultant force of the endless drawing means and the effective direction of the spring-damper mechanism can be kept constant.

A further advantageous embodiment is characterized in that a contact surface on the base body, which is prepared to be in contact with the engine block, is roughened in order to increase the force of the friction force fit.

Additionally or alternatively, a contact surface on the engine block, which is prepared to be in contact with the body, is roughened to increase the force of Reibkraftschlusses.

The tensioning wheel carrier is advantageously designed as a sheet metal forming part. Alternatively, a design as aluminum die-cast part is advantageous.

The inventive concept also includes an automotive powertrain having an endless traction means deployed for torque transmission. In that motor vehicle drive train, the endless traction means is stretched at least over a traction mechanism according to the invention.

In other words, it can be said that a toothed belt tensioner is the subject of the invention, which realizes a tensioning and damping movement linearly or linearly / rotationally. Here, the introduction of clamping force, guidance and support in the traction means on the tensioning wheel, which is also referred to as Pulley allows. This tensioning wheel is made of sheet metal, plastic injection molding or die-cast aluminum.

According to the invention, the biasing spring, linear guide and hydraulic unit are preferably placed within the tensioning wheel, which has a positive effect on the installation space.

The main body of the toothed belt tensioner is attached to the engine block. Preferably, that attachment is realized via a frictional engagement between the base carrier / base body and the mating surface on the internal combustion engine. The force required for this purpose is preferably applied with a fastening screw. Optionally, at least one of the two corresponding surfaces may additionally be roughened, for example via a friction-increasing coating or also incorporated structures. Thus, the clamping force is reducible and a smaller one Screw diameter possible, which additionally reduces the space requirement.

It is also possible to reinforce that connection via an additional positive fit. This again results in a smaller screw cross section.

The bias voltage at a motor stall or an engine start is realized by means of the biasing spring. Possible springs here may be helical compression springs, tension springs, leaf springs, torsion springs, spring rings, spiral springs, laterally arranged coil springs or torsion springs. The arrangement of the springs is adaptable to the particular case. Basically, the bias can be done by a spring assembly in series / parallel connection, consisting of one or more piston springs or biasing springs.

With regard to the assembly, it should be noted that the hydraulic element of the spring-damper mechanism and the guide with respect to the resulting belt force on the tensioning wheel are preferably aligned at an angle of -120 ° to + 120 °.

Furthermore, the hydraulic element and guide with respect to the center of the tensioning wheel is offset by at most twice the width of the tensioning wheel axially to the rear or to the rear. The hydraulic element and guide should be offset in relation to the symmetry axis of the end face of the tensioning wheel in this case by a maximum of 60% of the diameter of the tensioning wheel in both directions.

In principle, the support and damping of Zugmiteschwingung during operation mechanically or hydraulically be forced.

The tensioner roller is mounted on a roller bearing with respect to the sliding ring. This is preferably designed as a single or double row ball bearings to cause low friction losses and minimal heating. The single-row rolling bearing is preferably designed as an angular contact ball bearing or a four-point bearing. This allows the absorption of larger tilting moments.

Alternatively, the embodiment is possible as a sliding bearing. In this case, the use of a hydrodynamic sliding bearing is particularly desirable, since this causes a small space, and a high efficiency.

• 1 eine Schnittansicht eines erfindungsgemäßen Zahnriemenspanners in einer ersten Ausführungsform;
• 2 eine Seitenansicht des Zahnriemenspanners aus 1 mit einem angelegten Montagewerkzeug;
• 3 eine perspektivische Ansicht des Zahnriemenspanners aus 2;
• 4 eine Schnittansicht durch den Zahnriemenspanner, der auf einem Motorblock befestigt ist;
• 5 eine Schnittansicht des Zahnriemenspanners in einer weiteren Ausführungsform;
• 6 einen Längsschnitt durch den Zahnriemenspanner aus 5;
• 7 einen Längsschnitt durch den Zahnriemenspanner durch eine weitere Ebene;
• 8 eine Schnittansicht des Zahnriemenspanners in einer weiteren Ausführungsform;
• 9 den Zahnriemenspanner aus 8 in einer abgedeckten Ansicht;
• 10 den Zahnriemenspanner aus 8 in einer perspektivischen Ansicht;
• 11 den Zahnriemenspanner mit angesetztem Montagewerkzeug;
• 12 den Zahnriemenspanner aus 11 in einer Draufsicht;
• 13 eine weitere Ausführungsform des Zahnriemenspanners; und
• 14 eine perspektivische Ansicht des Zahnriemenspanners in einem toleranzausgeglichenen Zustand.

The invention will now be explained in more detail with reference to figures, in which context also different embodiments are explained. The figures show:

• 1 a sectional view of a toothed belt tensioner according to the invention in a first embodiment;
• 2 a side view of the toothed belt tensioner 1 with a fitted assembly tool;
• 3 a perspective view of the toothed belt tensioner 2 ;
• 4 a sectional view through the toothed belt tensioner, which is mounted on an engine block;
• 5 a sectional view of the toothed belt tensioner in a further embodiment;
• 6 a longitudinal section through the toothed belt tensioner 5 ;
• 7 a longitudinal section through the toothed belt tensioner through another level;
• 8th a sectional view of the toothed belt tensioner in a further embodiment;
• 9 the toothed belt tensioner off 8th in a covered view;
• 10 the toothed belt tensioner off 8th in a perspective view;
• 11 the toothed belt tensioner with attached assembly tool;
• 12 the toothed belt tensioner off 11 in a plan view;
• 13 another embodiment of the toothed belt tensioner; and
• 14 a perspective view of the toothed belt tensioner in a tolerance balanced state.

The figures are merely schematic in nature and are for the sole purpose of understanding the invention. The same elements are provided with the same reference numerals. The individual features can be interchanged.

1 shows a toothed belt tensioner 1 for a control drive of a motor vehicle, with a basic carrier acting as a base 2 which can also be referred to as a basic body. In the basic carrier 2 is a slot 3 available. This preferably has two parallel edges, which are each closed by a semicircle. Alternatively, the embodiment of the slot 3 as ellipse / oval shape possible.

On the ground support 2 is a linearly movable sliding ring 4 arranged on which a tension roller 5 rotatably seated. The sliding ring 4 , which can also be referred to as Spannradträger, is tolerance compensating via a linear spring arranged. The tension roller 5 contacts a toothed belt, not shown.

To the toothed belt tensioner 1 in a state where manufacturing tolerances between an engine block and the toothed belt tensioner 1 have been balanced, bias against the timing belt, is the position of the basic carrier 2 over one in the slot 3 used fastener 6 variably fixable.

The toothed belt tensioner off 1 Replaces the usual in the art torsion springs so on the one hand by a in 1 not visible linear spring and on the other hand is able to the belt on the relative position between the base support 2 and the sliding ring 4 pretension.

To provide a tension and a damping function of the belt over the toothed belt tensioner 1 To realize is a spring-damper mechanism 7 in the basic carrier 2 integrated. This consists in the present case of a coil spring 8th as well as a damping room 9 together. In the muffling room 9 is about a damping fluid via a hydraulic line shown later 14 brought in.

For mounting the toothed belt tensioner 1 is a tool receiving opening 10 arranged. This is from the spring-damper mechanism 7 arranged on the opposite side as the slot 3 , It is also smaller in its opening area than this.

In 2 is the toothed belt tensioner 1 shown in a longitudinal section. Here is an assembly tool 11 putting in a tool pad 17 related to 6 is shown, engages, shown. The tool support surface shown in more detail in connection with FIG. 14 23 is spaced accordingly, so that from the leverage of the assembly tool 11 a linear displacement force in the tool receiving opening 10 results.

To the tension roller 5 opposite the sliding ring 4 to store, is a double row of rolling bearings 12 arranged. On the mounting tool 11 facing away from the toothed belt tensioner 1 is a support pin 13 arranged to support resulting torques against the engine block.

2 also shows the previously presented hydraulic line 14 which is responsible for the damping of the spring-damper mechanism 7 necessary is.

In 3 is the toothed belt tensioner 1 shown in a perspective view. Here, different acting forces are entered by means of arrows.

The arrow P1 Sets the direction of the assembly force when adjusting the timing belt tensioner 1 dar. A first supporting force P2 acts on the tool support surface 23 on the assembly tool 11 , A second supporting force P3 acts from the tool receiving opening 10 on the assembly tool 11 ,

Is the timing belt tensioner 1 mounted, a belt force acts during operation P5 on the toothed belt tensioner 1 , This returns that tension via a biasing force P4.

In 4 is the toothed belt tensioner 1 fixed on the engine block. The pin 13 provides a corresponding torque counteracting effect on the toothed belt tensioner 1. Via a bolting torque P6 becomes the basic carrier 2 so fixed relative to the engine block that a clamping force 7 ensures a friction force.

In 5 an embodiment is shown, in which the fastening element 6 from a filler 15 is surrounded. This sits form-fitting in the slot 3 , similar to a sliding block. This forms an engine-side end surface of the filler 15 with a corresponding mating contour in the engine block a form-fitting, whereby in that embodiment no support pin 13 necessary is.

At that point is how in 6 shown, a torque support 16 arranged. This acts as a torque counteraction. It is on the opposite side of the timing belt tensioner 1 as the mounting tool pad 17 arranged. The further reference numerals 6 have already been explained in connection with the other figures.

In 7 is the toothed belt tensioner 1 shown in another view. This is how the spiral spring runs 8th out of the drawing plane. It can be seen that the longitudinal axis of the fastener 6 skewed to the direction of action of the coil spring 8 runs.

In the 8th to 10 are toothed belt tensioners 1 with a mounting eccentric 18 shown. This is suitable for making tolerance compensation in conjunction with a torsion spring.

A setting screen 19 , which is represented here by two flush arrows, indicates the tolerance-balanced state. In that state is the basic carrier 2 relative to the sliding ring 4 So in a tolerance-free starting position to be biased. A basic carrier-side display 20 is in flight with a scroll-side ad 21 bring to. The further reference numerals from the 8th to 10 have already been explained in connection with the other figures.

11 shows the engagement of the assembly tool 11 in the basic carrier 2 , The fastener 6 stands out in this case many times, such as the factor 4 , deeper into the engine block, not shown here as the Abstützpin 13 , The rolling bearings 12 are again arranged in a double row.

In 12 it can be seen that the assembly tool 11 as long along the arrow above P1 is turned until the two ads 20 and 21 lie flush over one another and thus represent a tolerance-balanced state.

In 13 is the storage between the tension pulley 5 and the sliding ring 4 visible, noticeable. The other components are known from the previous figures.

Finally shows 14 the support between the Montagewerkzeugt 11 and the tool support surface 23 in a perspective view. As with the two arrows 20 and 21 the setting screen 19 can be seen, the tolerance-balanced state is present.

LIST OF REFERENCE NUMBERS

1

timing belt tensioner

2

base support

3

Long hole

4

sliding ring

5

idler

6

fastener

7

Spring-damper mechanism

8th

spiral spring

9

damping space

10

Tool receiving opening

11

assembly tool

12

roller bearing

13

Abstützpin

14

hydraulic line

15

filling

16

torque support

17

Mounting tool rest

18

Montageexzenter

19

Setting screen

20

Basic carrier-side display

21

Scroll-side display

22

Adjusting

23

Tool support surface

P1

Direction of the installation force

P2

first supporting force

P3

second supporting force

P4

preload force

P5

belt force

P6

Anschraubmoment

P7

clamping force

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 19631588 A1 [0005]
• JP 11132299 H [0006]
• JP 11132298 H [0007]

Claims (1)

Toothed belt tensioner (1) for a control drive of a motor vehicle, having a basic carrier (2) acting as a base, in which a slot (3) is present, and having a sliding ring (4) which can be moved linearly relative to the base carrier (2) on which a tensioning roller (4) 5) is rotatably mounted, wherein a linear spring for biasing of the tension roller (5) contacted toothed belt is used and wherein in a tolerance balanced state, the position of the base support (2) via a in the slot (3) inserted fastening element (6) is fixed ,

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