DE102015211227B4 - Cold-startable electric motor-assisted ring tensioner - Google Patents

Abstract

Traction device tensioner (1) for a traction mechanism drive of an internal combustion engine, comprising:
A first clamping arm (2) and a second clamping arm (3), which are rotatable relative to one another and each provided with a tensioning roller (4, 5) biasing the traction means,
- A between the clamping arms (2, 3) clamped spring means (6) which biases the tension rollers (4, 5) to each other,
- And an actuator (7) for rotating the clamping arms (2, 3),
characterized in that the actuator (7) is arranged in parallel connection with the spring device (6) between the clamping arms (2, 3).

Description

• – einen ersten Spannarm und einen zweiten Spannarm, die relativ zueinander verdrehbar und jeweils mit einer das Zugmittel vorspannenden Spannrolle versehen sind,
• – eine zwischen den Spannarmen eingespannte Federeinrichtung, die die Spannrollen aufeinander zu spannt,
• – und einen Aktor zur Verdrehung der Spannarme.

The invention relates to a Zugmittelspanner, preferably a belt tensioner, for a traction mechanism drive / belt drive of an internal combustion engine, such as a gasoline or diesel engine, a motor vehicle. The Zugmittelspanner includes:

• A first clamping arm and a second clamping arm, which are rotatable relative to one another and each provided with a tensioning roller biasing the traction means,
• A spring device clamped between the clamping arms, which clamps the tensioning rollers towards one another,
• - And an actuator for rotating the clamping arms.

Such Zugmittel- or pendulum clamps are already generic from the state of the art DE 39 33 878 A1 and the FR 2 781 008 A1 known.

The DE 10 2007 051 228 A1 discloses a tensioning device for a traction mechanism drive of an internal combustion engine with a tensioning roller and a spring mechanism for generating a coupled via the tensioning roller in a traction means of the traction mechanism clamping force. A clamping additional element is further provided, wherein the clamping or supporting force is adjustable by means of a pressure medium, for tuning the acting on the traction means tensioning roller clamping force.

Further prior art is known from DE 101 18 277 A1 , of the DE 10 2011 082 764 A1 and DE 10 2012 218 455 A1 known.

There are thus already known from the prior art various designs of Zugmittelspannern. However, it has been shown that these tensioning means tensioners often have the disadvantage that they are essentially dependent on the mechanical properties of the spring device with respect to the clamping force acting on the tensioning rollers during operation. The amount of clamping force is dependent on the spring travel of the spring device, d. H. from the relative position between the two clamping arms. An adjustment of the clamping force of the tension rollers in the respective relative position of the clamping arms, such as changing temperature conditions, this is difficult or impossible.

It is therefore the object of the present invention to remedy the known from the prior art disadvantages and in particular to provide a Zugmittelspanner available in which the biasing force of the tension rollers should be more easily adjustable to the respective operating conditions.

This is inventively achieved in that the actuator is arranged in parallel with the spring device between the clamping arms.

In the form of the actuator independent of the spring device adjustment is present, which can change the relative position of the two tension rollers to each other and thus also the bias of the tension means generated by the tensioning rollers with respect to the spring means. Thereby, the biasing force of the mostly start-stop-capable Zugmittelspanner embodiments is adjustable, with a cold start capability is easily achieved. With the actuator used, the bias of the traction means can be increased so that the traction means can transmit the necessary torque during engine cold start. At the same time, a reduction of the spring preload can occur. With the actuator used, the bias of the traction device can also be reduced (relief of the spring), which in turn the traction means z. B. relieved at constant speed. As a result, a reduction in friction can be achieved, whereby the emission of CO _{2 of} the internal combustion engine is further reduced. Thus, it is easily possible to increase the biasing force of the traction means in the cold start process, turn to reduce again at a constant engine speed. As a result, a particularly variable support for the variable bias of the traction means is implemented.

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

Accordingly, it is advantageous if the clamping arms are annular and are rotatable relative to each other about a common axis of rotation. Such Zugmittelspanner be referred to as ring tensioner due to the annular design of the clamping arms.

Accordingly, it is also advantageous if the actuator has an electric motor or if the actuator is designed as an electric motor. This electric motor is particularly directly controlled during operation, whereby the tension rollers can be adjusted specifically targeted.

If an actuator housing of the actuator, which is fixedly connected to a stator of the actuator and / or rotatably fixed to the stator, is fastened to the first clamping arm, the actuator is particularly cleverly mounted.

In this context, it is particularly advantageous if the actuator housing at an axial end face of the annular clamping arm, in the circumferential direction of the clamping arms spaced from the tension rollers, is arranged. As a result, the Zugmittelspanner is designed to save space.

In addition, it is useful if a rotor of the actuator is rotatably connected to an output shaft / an output shaft is formed by a rotor of the actuator, wherein the output shaft axially penetrates the first clamping arm to one (axial) side of the second clamping arm. As a result, the actuator is mounted particularly space-saving.

Furthermore, it is also expedient if the output shaft has a toothing which meshes with a counter toothing on the second clamping arm. As a result, the actuator is directly operatively connected to the two clamping arms and acting between these two.

In other words, it is therefore advantageous if the actuator is drivingly / movably coupled to the second clamping arm by means of an output shaft and at the same time is firmly supported / fastened / fixed on the first clamping arm.

In this context, it is also advantageous if the counter-toothing is formed as an external toothing. The counter-toothing is further preferably attached to an outer peripheral side of the second clamping arm. As a result, the corresponding torque is transmitted particularly effectively by the actuator.

If the actuator is designed in such a way that, in a first drive state, it twists the second tensioning arm relative to the first tensioning arm, so that the spring device relaxes, ie. H. the biasing force of the spring means relaxed / reduced, the actuator acts to support the spring means and the biasing force, which was generated by the spring means, a.

Furthermore, it is also advantageous if the actuator is designed such that it rotates in a second drive state, the second clamping arm relative to the first clamping arm, so that the two tension rollers are rotated away from each other. This works in a further operating state against the biasing force of the spring to produce a low bearing friction in the traction drive especially at high speeds.

The invention will now be explained in more detail with reference to figures.

Show it:

1 an isometric view of a Zugmittelspanners invention according to a preferred embodiment, wherein the Zugmittelspanner is shown from a front side on which the actuator is attached to the first clamping arm,

2 an isometric representation of the in 1 shown Zugmittelspanners, but now from a rear side, ie a side which rests on a generator housing during operation of Zugmittelspanners,

3 an exploded view of Zugmittelspanners after the 1 and 2 in an isometric view, wherein the design of both clamping arms is clearly visible,

4 an isometric view of a likewise shown in exploded partial assembly of Zugmittelspanners after the 1 to 3 , wherein the representation of the tension rollers and the end cover is dispensed with and particularly well the attachment and design of the spring means in the form of the bow spring is recognizable,

5 a rear view of Zugmittelspanners after the 1 to 3 , based on the representation of in 2 still mounted end cap is omitted and in particular the arrangement of the two tension rollers along the circumference of the two clamping arms is visible,

6 an isometric view of the second provided for the spring device support lever clamping arm,

7 a detailed view of the in the Zugmittelspanner after the 1 to 3 used actuator in isometric view, which is positioned at a distance from the operatively engaged / meshing with him second clamping arm, and

8th a detailed view of the actuator housing in operation receiving portion of the first clamping arm, through which the output shaft of the actuator protrudes, wherein the second clamping arm is not yet fully in its intended end position, in which the counter-toothing meshes with the output shaft is arranged.

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.

In 1 is the Zugmittelspanner invention 1 particularly vividly illustrated. The tensioning device 1 is designed for tensioning a designed as a belt, endless traction means, ie designed as a belt tensioner. The belt, which is not shown here for clarity, is designed as a V-ribbed belt. The belt / traction means is in operation of an internal combustion engine by means acting as a pendulum tensioner tensioner 1 biased. Especially effective is the Zugmittelspanner 1 acting, as in this case, when the traction means / belt is part of an accessory traction drive / ancillary belt drive. Consequently tensioned tensioner 1 in operation / in an operating state, the traction means in the region of a traction and / or slack side, which traction means wraps around both an output shaft / crankshaft of the internal combustion engine and a generator pulley of a generator.

The tensioning device 1 is designed as a ring tensioner. The tensioning device 1 Therefore, has two closed ring-shaped clamping arms 2 . 3 on. The first tension arm 2 and the second tension arm 3 have a common axis of rotation about which they are rotatable relative to each other. Both clamping arms 2 . 3 are also arranged axially adjacent to each other. Every clamping arm 2 . 3 has a tension roller 4 respectively. 5 on to bias the traction means. The (first) tension pulley 4 of the first clamping arm 2 is positioned so that in a first operating state of the internal combustion engine, in which the output shaft drives the generator shaft, the traction means in a first section in the direction of traction means after the generator shaft (first section referred to as Zugtrum) biases. The (second) tension pulley 5 of the second clamping arm 3 is positioned so that in a second operating state of the internal combustion engine, preferably at a start of the internal combustion engine in which the generator shaft drives the output shaft / crankshaft, the traction means in a second section in the direction of traction means after the crankshaft (second section referred to as idle strand) biases.

The first tension arm 2 as he is especially good at 3 and 4 is shown, has in the usual way an annular body 14 on, in a peripheral region on a radial outer side of a tensioner pulley 15 having. This tension pulley mount 15 is as a receptacle for attaching the first tensioner 4 educated. In this case, the tension roller 4 a here for clarity, not shown in detail rolling bearing, which in operation with a bearing inner ring against rotation of the tensioner pulley 15 is attached. The first tensioner 4 moreover, at a further peripheral area spaced apart from the tensioning roller receiving 15 on her body 14 a receiving chamber 16 on, which is used as a bow spring 17 trained spring device 6 serves. The bow feather 17 , such as in 4 to recognize, is a spring which extends arcuately and is implemented as a helical compression spring. The bow feather 17 extends here by a certain angular range in the circumferential direction along the annular body 14 , In this embodiment, the bow spring extends 17 depending on the bias state at an angle between 90 ° and 180 ° within the receiving chamber 16 , The substantially trough-shaped, also extending in the circumferential direction receiving chamber 16 forms a housing of the bow spring 17 / the spring device 6 and surrounds these both in a first, from the second clamping arm 3 opposite axial side, in the radial direction and in the circumferential direction. The bow feather 17 is thereby in the receiving chamber 16 taken and deformed in this, with the leadership and support of the bow spring 17 also several shoes 26 are placed on this radially from the outside.

Into the receiving chamber 16 protrudes in the operating state of Zugmittelspanners 1 a in 6 to recognizing support lever 18 of the second clamping arm 3 into it, with the support lever 18 is arranged such that it the spring means 6 / Bow spring 17 supported at a circumferential end. This support lever 18 thus forms for the bow spring 17 a support in a first circumferential direction. The bow feather 17 is then in turn in one of these first circumferential direction opposite second circumferential direction on the second clamping arm 3 , namely on the peripheral wall 19 the receiving chamber 16 supported. Consequently, the relatively rotatable clamping arms 2 . 3 by means of the bow spring clamped in between 17 so applied with torque, that the two tension rollers 4 . 5 be stretched towards each other.

The second clamping arm 3 points, also like the first tension arm 3 an annular base body, hereinafter referred to as a second main body 20 referred to. Also this basic body 20 has on a radial outer peripheral side of a tension roller, hereinafter referred to as the second tensioner pulley 21 referred to. This second tension pulley mount 21 also serves to attach a bearing inner ring of a rolling bearing of the second tensioner 5 , The second tension pulley mount 21 but protrudes parallel to the first tensioner pulley 15 through a recess 22 on the outer peripheral side of the main body 14 of the first clamping arm 2 therethrough. The two tension roller mounts 15 and 21 and thereby also the two tension rollers 4 and 5 are arranged at the same axial height (seen along the axis of rotation). The tension rollers 4 and 5 again are the same for the sake of simplicity. In the circumferential direction of the second clamping arm 3 offset to the tension pulley mount 21 is then again the support lever 18 on the second body 20 appropriate. As continues in 3 is clearly visible, is the second basic body 20 rotatable in a guide ring 25 arranged. This guide ring 25 is in the attached state of Zugmittelspanners 1 firmly between the first clamping arm 2 and the end cover 23 clamped, creating the second clamping arm 3 is stored safely in the axial direction.

In 2 is further to realize that a cover 23 non-rotatable with the first clamping arm 2 is connected, wherein this on the first clamping arm 2 it is arranged that he together with the first clamping arm 2 a housing of the second clamping arm 3 forms.

According to the invention is an actuator 7 provided in the 7 and 8th easy to recognize. This actor 7 is in parallel with the spring device 6 between the first and the second clamping arm 2 . 3 arranged so that it is in operation by the spring device 6 on the tension rollers 4 . 5 can change the applied clamping force. The actor 7 is thus arranged such that the Zugmittelspanner 1 acts on the outside torque-free and - unlike in the cited prior art freely rotating on the traction and the slack side of the traction device can align.

The actor 7 includes an electric motor 8th and is with his actuator housing 9 rotatably, namely by means of a screw, on the first clamping arm 2 attached. Like this, for example, in 1 It can be seen, is the electric motor 8th with its actuator housing 9 at a second clamping arm 3 facing away from the axial end face of the first clamping arm 2 to this first clamping arm 2 fitting and attached. This is the actor 7 non-rotatable (with its actuator housing 9 ) with the first clamping arm 2 connected.

As continues in 8th The first clamping arm is particularly well recognizable 2 in the main body 14 a through hole 24 in the form of a through hole. Through this through hole 24 protrudes an output shaft 10 of the electric motor 8th / the actor 7 , This output shaft 10 is non-rotatable with a rotor of the electric motor 8th , which is not shown here for clarity, connected. Rather, the output shaft 10 even here formed as a stoffeinteiliger part of the rotor. The electric motor 8th has in the usual way next to the rotor on a stator fixed to the stator, depending on the current supply to the rotor / the output shaft 10 in a first or in a second direction of rotation drives. Furthermore, the output shaft 10 with a toothing 11 rotatably connected. This gearing 11 penetrates protrudes in the axial direction in a counter-toothing 12 on the second clamping arm 3 into it. This is the output shaft 10 in operation with the second clamping arm 3 engaged / motion coupled. The counter teeth 12 is again designed as external teeth and in a certain peripheral region of the second clamping arm 3 on the body 20 of the second clamping arm 3 arranged.

The actor 7 is further configured and acting so that in a first drive state, namely preferably a first rotational direction of the rotor, the second clamping arm 3 such relative to the first clamping arm 2 twisted that tension rollers 3 . 4 in the circumferential direction of the clamping arms 2 . 3 to be turned towards each other. This relaxes the spring device 6 ie the bow spring 17 , Due to the additional driving force of the actuator 7 in this first drive state is thus the spring device 6 so supported that the tension rollers 4 . 5 Press more strongly against the empty or traction of the respective traction device. This is implemented in particular during a cold start of the internal combustion engine.

In a second drive state, one of the first opposite second rotational direction of the rotor, then the first and the second clamping arm 2 . 3 twisted each other so that the tension rollers 4 . 5 in the circumferential direction of the clamping arms 2 . 3 Move away from each other and their pressure on the traction means reduced in favor of a reduced drive friction.

LIST OF REFERENCE NUMBERS

1

Zugmittelspanner

2

first tension arm

3

second clamping arm

4

first tension roller

5

second tensioner

6

spring means

7

actuator

8th

electric motor

9

actuator housing

10

output shaft

11

gearing

12

counter teeth

13

external teeth

14

Basic body / first basic body

15

Tension pulley mount / first tension pulley mount

16

receiving chamber

17

bow spring

18

support lever

19

peripheral

20

second basic body

21

Tension pulley mount / second tension pulley mount

22

recess

23

End cover

24

Through Hole

25

guide ring

26

shoe

Claims (7)

Traction device tensioner ( 1 ) for a traction drive of an internal combustion engine, comprising: - a first clamping arm ( 2 ) and a second tensioning arm ( 3 ), which are rotatable relative to each other and each with a tensioning means biasing the tensioning roller ( 4 . 5 ), - one between the clamping arms ( 2 . 3 ) clamped spring device ( 6 ), which are the tension rollers ( 4 . 5 ), and an actuator ( 7 ) for rotating the clamping arms ( 2 . 3 ), characterized in that the actuator ( 7 ) in parallel with the spring device ( 6 ) between the clamping arms ( 2 . 3 ) is arranged. Traction device tensioner ( 1 ) according to claim 1, characterized in that the clamping arms ( 2 . 3 ) are annular and are rotatable relative to each other about a common axis of rotation. Traction device tensioner ( 1 ) according to claim 1, characterized in that the actuator ( 7 ) an electric motor ( 8th ) having. Traction device tensioner ( 1 ) according to claim 3, characterized in that one with a stator of the actuator ( 7 ) fixedly connected actuator housing ( 9 ) on the first clamping arm ( 2 ) is attached. Traction device tensioner ( 1 ) according to claim 4, characterized in that a rotor of the actuator ( 7 ) rotatably with an output shaft ( 10 ) connecting the first tensioning arm ( 2 ) axially to one side of the second clamping arm ( 3 ) penetrates. Traction device tensioner ( 1 ) according to claim 5, characterized in that the output shaft ( 10 ) a gearing ( 11 ), which with a counter-toothing ( 12 ) on the second tensioning arm ( 3 ) combs. Traction device tensioner ( 1 ) according to claim 6, characterized in that the counter-toothing ( 12 ) as an outer toothing ( 13 ) is trained.

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