DE102004009129A1 - Tensioner for a continuous belt, e.g. at a motor camshaft, has a rotating belt deflection roller on an eccentric turning around a housing pin according to the belt working duration and with a sensor for the eccentric setting - Google Patents

Abstract

The tensioner for a continuous belt, and especially at a motor camshaft, has a rotating deflection roller (22) on an eccentric (14). The eccentric turns on a pin (8) at a housing (6) according to the working time of the continuous belt. A change interval of the belt is signaled by a sensor (54), which registers the relative position of the eccentric against the housing. The signal unit is a circular ring permanent magnet (12) integrated into the eccentric, to work with the sensor integrated into the base plate (2) of the housing.

Description

Territory of invention

The The invention relates to a tensioning device of a endless drive, in particular with a belt, preferably in the camshaft drive of an internal combustion engine, with an overflowed from the Endlostrieb Roller, which is rotatably mounted on a working eccentric, the depending on the service life of the endless drive relative to a roller supporting Spigot of a housing twisted, and with a change interval of the endless drive indicative Signaling device with a sensor showing the relative position of the working eccentric to the housing sensed.

background the invention

It are diverse Belt drives are known in which the tensioning of the belt over the Lifetime accomplished by means of separate clamping devices becomes. In order to make optimum use of the life of such a belt, has already been proposed, arranged in the course of Endlostriebes To provide clamping devices with a suitable sensor. Such Belts are usually encapsulated and arranged difficult to access, so that's a maximum extension the replacement interval to reduce costs desirable is. With the help of the mentioned sensors, under deviation from firmly specified change intervals the state of wear of the belt currently determined and up to the limit of the permissible service life be exploited. The problem here is, however, the installation space situation, for example, with regard to the wiring to be made.

A Such tensioning device has become known by the company NTN (Www.ntn.co.jp/english/corp/news/news20011001_2.html). This detected the elongation state of the belt and excludes this condition on its life. This known tensioning device is especially for the camshaft drive by means of belts in internal combustion engines suitable. Therefor the tensioning device has a change interval of the endless drive indicating signaling device and one overrun by the belt Roll on which is rotatably mounted on a working eccentric, depending on the service life of the endless drive relative to a roller supporting Spigot of a housing rotated, wherein a sensor of the signaling device, the relative position of the working eccentric to the housing sensed.

When Sensor finds a Hall sensor application, which is in a separate casing is arranged, this housing on a bearing housing a hydraulic ram is placed. This bearing housing is rigidly mounted on the internal combustion engine and takes, inter alia a hydraulically extendable stamp on which the necessary Tension on the belt for the purpose of the mentioned wear-related Re-enactment applies.

In The working eccentric are two pin-shaped permanent magnets in introduced a predetermined distance from each other, wherein one forms the magnetic north pole and the other the corresponding south pole. The working eccentric twists during operation depending on the wear a certain amount, wherein the relative position of the two magnetic Pole to the Hall sensor changed. As a result, changes Its output voltage, which conclusions about the elongation state of the belt allows. The for the Hall sensor necessary wiring is separately formed and attached its housing brought in or out.

Task of invention

In front The invention is therefore based on the object to develop such a clamping device such that a space optimal Arrangement also for the signaling device necessary components is realized.

Summary the invention

Therefore the invention is based on a tensioning device of a endless drive, in particular with a belt, for example in the camshaft drive an internal combustion engine, with a overflowed from the Endlostrieb Roller, which is rotatably mounted on a working eccentric, the in dependence the service life of the endless drive relative to a roller supporting Spigot of a housing twisted, and with a change interval of Endlostriebes indicating Signaling device with a sensor showing the relative position of the working eccentric to the housing sensed.

to solution the task is the clamping device in addition in that the signal device is one in the working eccentric has integrated arranged annular permanent magnets, which is arranged with the incorporated in a base plate of the housing Sensor interacts.

This structure is associated with the advantage that the entire clamping device takes up less space, since on the one hand, the sensor is housed in the housing, and on the other hand, a circular permanent magnet in it easier way to integrate space saving in the work eccentric.

In preferred embodiment of this tensioning device is the base plate designed as a printed circuit board with conductor tracks. This is omitted expansive, from the outside patch cabling or contacts.

So is it possible, for example? and is included in the invention that the obtained sensor data and / or derived quantities wirelessly by means of a suitable radio device to a signaling technology downstream control device for example, for triggering a belt change signal are forwarded.

moreover is preferably provided that for isolation purposes, the base plate is encapsulated with an electrically insulating plastic, which the makes entire device at this point insensitive to external media influences.

Prefers is it for a space-saving functional integration further provided that on the base plate holding means for the clamping device and adjustment means for the alignment of the working eccentric are formed. This structure bears together with the others Design features also to facilitate installation of the overall device at.

In Another embodiment of the invention is the working eccentric below Interposed a plain bearing bush supported on the pin, whereby a further space reduction can be achieved by that the plain bearing bush is formed by the permanent magnet or this is integrated in the plain bearing bushing.

to Further optimizations is the sensor designed as a Hall sensor space-saving embedded in a receptacle of the base plate, wherein the Recording preferably electrical contacts are assigned.

With the previously indicated measures Is it possible, the sensor and any required plug directly on the circuit board to contact. At this are directly the necessary fasteners for the Clamping device integrally formed so that a prefabricated, plastic-molded unit is created.

Favorable Way allows the embodiment of the invention also a flexible adaptation to existing tensioner concepts, since no fundamental changes to perform on known tensioners are.

Short description the drawings

The The invention will be described below with reference to the accompanying drawings on some embodiments explained in more detail. In this shows

1 a perspective view of a working eccentric of the clamping device with inserted permanent magnet,

2 a perspective view of a base plate with pins,

3 a perspective view of a base plate with integrated holding and adjusting means and

4 a section through a complete clamping device approximately along the line IV - IV according to 1 ,

detailed Description of the drawings

A Clamping device with a endless belt having a belt is in a camshaft drive of an internal combustion engine for a motor vehicle built-in. Such camshaft drives are well known and therefore require none nearer Explanation.

Such a tensioning device is provided with a base plate 2 provided, which hook-shaped fastening means 4 has, with which the entire clamping device can be fixed to a crankcase of the internal combustion engine.

The base plate 2 is part of a housing 6 , which one firmly with the base plate 2 connected pins 8th with an internal adjustment eccentric 10 and an outer plain bearing bush 11 having. On the cone 8th is a work eccentric 14 arranged on which an inner ring 16 a double row ball bearing 18 is deferred. A corresponding outer ring 20 carries a role 22 , over which the belt of the Endlostriebes not shown running.

The working eccentric 14 indicates at its the base plate 2 of the housing 6 facing side 24 an annular recess 26 on, in which a torsion spring 28 is included. An end 30 this spring 28 is bent in a recess 32 an outer boundary wall 34 the depression 26 established.

At the side 24 facing end of the working eccentric 14 is in a turnout 36 a central opening 38 a permanent magnet 12 turned sets. For an interlocking system has an inner wall 40 a recess 42 for a corresponding nose 44 of the permanent magnet 12 on. The boundary wall 34 carries a molded-on pointer 46 as part of adjusting means of the tensioning device. As a counterpart to this pointer 46 is at the base plate 2 an attack 48 integrally formed, which has a Einstellkerbe 50 wearing.

In a recording 52 the base plate 2 is a sensor acting on the Hall principle 54 integral part of this base plate 2 and thus of the housing 6 , For electrical contacting of this sensor 54 is the base plate 2 designed as a printed circuit board with integrated electrical conductors.

The power supply or the signal output from the housing 6 can be connected directly to the conductor tracks of the base plate 2 and the crankcase or by the lines shown in the drawing 56 respectively.

For isolation purposes and to protect against media influence is formed as a printed circuit board base plate 2 including the fasteners 4 , the stop 48 etc. encapsulated with an electrically insulating plastic.

The passive permanent magnet 12 and the electrical current-carrying components are part of a signal indicating the wear or elongation state of the belt signaling device. This is connected in a known manner in the further course with a suitable display device for visualizing the state of wear.

In a first orientation of the clamping device is first using the adjustment eccentric 10 approached a basic position, then after placing the belt by rotation of the working eccentric 14 applied the necessary tension. This is achieved when the pointer 46 congruent with the adjustment notch 50 is aligned.

During operation, the belt overflows the roller 22 and puts them in rotation. This rotational movement is in the ball bearing 18 between the circumferential outer ring 20 and the stationary inner ring 16 added. Without elongation of the belt, there is no relative movement between the working eccentric 14 and the pin 8th , The permanent magnet 12 is always in the same relative position to the sensor 54 , which supplies as a result always an equal output voltage.

However, if there is wear or elongation of the belt due to aging, so sets the torsion spring 28 through the plain bearing bush 11 from the cone 8th Rotary coupled work eccentric 14 until reaching the desired belt tension. At this relative rotation, the permanent magnet changes 12 his position to the sensor 54 , whereby its output voltage changes the state of wear of the belt signaling.

2

baseplate

4

fastener

6

casing

8th

spigot

10

adjusting eccentric

11

plain bearing bush

12

permanent magnet

14

working eccentric

16

inner ring

18

ball-bearing

20

outer ring

22

role

24

page

26

deepening

28

torsion spring

30

The End

32

recess

34

boundary wall

36

recess

38

central opening

40

inner wall

42

recess

44

nose

46

pointer

48

attack

50

Einstellkerbe

52

admission

54

sensor

56

management

Claims (10)

Clamping device of a endless drive, in particular with a belt, preferably in the camshaft drive of an internal combustion engine, with a roller overflowed by the endless drive ( 22 ) rotatably mounted on a working eccentric ( 14 ), which depends on the operating time of the endless drive relative to a roller ( 22 ) supporting pin ( 8th ) of a housing ( 6 ), and with a signal indicating a change interval of the endless drive with a sensor ( 54 ), which determines the relative position of the working eccentric ( 14 ) to the housing ( 6 ) sensed, characterized in that the signaling device one in the working eccentric ( 14 ) integrated, annular permanent magnet ( 12 ), which with the in a base plate ( 2 ) of the housing ( 6 ) integrated sensor ( 54 ) cooperates. Clamping device according to claim 1, characterized in that the base plate ( 2 ) is designed as a printed circuit board with integrated conductor tracks. Clamping device according to claim 1 or 2, characterized in that the sensor data and / or derived therefrom Sizes wireless by means of a suitable radio device to a signaling technology downstream control device can be forwarded. Clamping device according to claim 2 or 3, characterized in that the base plate ( 2 ) is encapsulated with a plastic. Clamping device according to one of the preceding claims, characterized in that on the base plate ( 2 ) integrally holding means ( 4 ) for the clamping device and adjustment means for the alignment of the working eccentric ( 14 ) are formed. Clamping device according to one of the preceding claims, characterized in that the working eccentric ( 14 ) with the interposition of a plain bearing bush ( 11 ) on the pin ( 8th ) is arranged supported. Clamping device according to claim 6, characterized in that the permanent magnet ( 12 ) as plain bearing bush ( 11 ) is trained. Clamping device according to claim 6, characterized in that the permanent magnet ( 12 ) in the plain bearing bush ( 11 ) is arranged integrated Clamping device according to one of the preceding claims, characterized in that the sensor ( 54 ) formed as a Hall sensor in a receptacle ( 52 ) of the base plate ( 2 ) is inserted and the recording ( 52 ) are assigned electrical contacts. Clamping device according to one of the preceding claims, characterized in that the permanent magnet ( 12 ) a form-fitting in a recess ( 42 ) of the working eccentric ( 14 ) engaging nose ( 44 ) having.