FR2833059A1 - WEAR DISPLAY DEVICE FOR A TENSIONING DEVICE, IN PARTICULAR FOR MOTOR VEHICLE EQUIPMENT - Google Patents

Abstract

Tensioning device (1) for a traction drive means having a fixed base part (2) and a pivoting support element (5) by means of a rotational bearing (14). ) integrated in the rotation bearing (14) allows electrical and / or galvanic separation.

Description

Field of the Invention The present invention relates to a device

tensioner for

  traction drive means of an internal combustion engine.

  The traction means of the trac drive means

  tion, for example a belt or chain, may be stretched by the

  positive tensioner, and connects different equipment of an internal combustion engine for example the water pump, the generator or alternator, the injection pump, or the compressor of the air conditioning system. Current internal combustion engines are usually equipped with two separate traction drive means. Next to the traction drive means for driving the equipment, a second traction drive means is used to drive the shaft

  to cam and so to the control of the gas exchange valves.

  The tensioning device providing the prestressing of the traction means comprises a fixed base piece connected by a rotational bearing to a pivoting support member relative to the base piece. The support member is provided with a rolling roller guided in rotation on the traction means; between the base piece and the support member there is provided a torsion spring or a helical spring providing a support

  o by a connection by the force of the tensioner roller against the traction means.

  Between the base piece and the support member there is a plain bearing. The

  smooth bearing-shaped binding is housed in the limited annular gap

  radially by the base piece and the support member.

  Current vehicles must meet very strict requirements regarding the reliability of the various components. In addition to increasing the service life of the traction means, the function of the tensioning device is to ensure, automatically, automatically

  sufficient prestressing that is to say without slippage of the traction means.

  This concerns among other things a tensioning device or tensioning device

  who must work without requiring maintenance.

  BACKGROUND OF THE INVENTION The tensioning device according to document DE-41 14 716-A1

  is provided with a regulating means which ensures that the pres-

  The traction of the traction means remains practically constant as a function of the state of connection of the equipment to be driven. The construction of this known tensioning device comprises a pivoting arm mounted to rotate and whose rolling roller, rotatably installed at one end, by a connection by force, supported by the force developed by the spring applied against the pivoting lever, comes against the traction means. The pivoting lever is further connected to an actuating member; regardless of the state of operation of the equipment driven by the traction drive means, the position of the pivoting lever is changed by the actuating member and thus it acts directly on the force of

  prestressing of the traction means.

  The known tensioning device has no solution which directly monitors the operation of the tensioning device or, in the event of a failure thereof, provides information to the driver of the vehicle or the mechanic so that at the time of a revision, he could

know the current state of wear.

  SUMMARY OF THE INVENTION The object of the present invention is to develop a voltage device which detects the operating state or the current wear of the device.

s bind smooth.

  To this end, the invention relates to a device of the type defined above, characterized in that - the tensioning device comprises a fixed base piece connected by a rotation band to a support member pivotally mounted on the base piece and said support member comprises a rolling roller guided against a traction means; - A torsion spring interposed between the base piece and the support member provides support by the force of the roller against the traction means; - An annular gap radially delimited by the base member and the support member receives a sliding bearing; the sliding bearing ensures at least one metallic or electrical and / or galvanic separation between the base part and the support element; both the base piece and the support member have an electrical connection contact and the damage of the plain bearing allows the

  current flow between the base piece and the support member.

  Thus according to the invention, an electrical connection is connected to both the base piece and the support member. The voltage applied to one of the parts, that is to say the base part or the support element and the ground connection to another corresponding part, makes it possible, in the event of a damaged plain bearing, to current and thus an electrical contact. For this purpose, the plain bearing is provided with a metallic and / or electrical and / or galvanic separation which, when new, prevents the passage of the neck.

  between the base piece and the support member.

  The invention makes it possible to display the wear of the plain bearing without having to disassemble the tensioning device. During a regularly scheduled maintenance visit, as part of the vehicle diagnosis, it is possible to determine the state of wear of the plain bearing and replace it if necessary. In addition, the wear display according to the invention comprises a signal transmission

  which permanently indicates to the driver of the vehicle the state of wear.

  The wear display according to the invention can thus prevent the vehicle from being blocked exceptionally or that it must be repaired outside the workshop visits. Since a failed sliding bearing can lead to a total failure of the tensioning device and to the stopping of the internal combustion engine or to the total stopping of the engine, the invention also improves the efficiency.

availability of the vehicle.

  The device according to the invention is advantageously applied to tensioning devices of different constructions such as, for example, friction disk devices, cone devices or else

  eccentric tensioning devices.

  A preferred embodiment of a friction disk tensioning device comprises a cylindrical stud, formed in one piece with the base member and rotatably receiving the support member. The support element which surrounds the stud by a hub, further defines a pivoting arm integrally connected to the hub and whose free end carries the roller pressed against the traction means. The plain bearing ensures electrical separation between the base piece and the support member; this bearing is placed between the envelope surface

  of the stud and the inner wall of the hub.

  An eccentric tensioning device has, with respect to a friction disk tensioning device, a construction at least optimized in the radial direction. The base piece may comprise a base plate provided with an axially protruding pin made in one piece. The eccentric-shaped support member is mounted to rotate on the stud and between the stud and the support member there is provided

a plain bearing.

  3s The metallic or electrical and / or galvanic separation between the base part and the support element is carried out according to the invention by the plain bearing. For this, the plain bearing comprises a metal support material provided with an insulating sliding layer. Preferably, the support material of the preferably tubular support body is galvanically coated with an insulating slip layer. In the new state or for a given wear state, the sliding layer prevents the passage of current through the plain bearing and thus cuts off the electrical element or the passage of the current between the base part and the element. sup port. For an eccentric tensioning device, the invention provides a sliding bearing which in the mounted state is preferably treated in a receiving bore of the support member. The plain bearing is thus supported by the

  o sliding layer against the envelope surface of the base piece.

  In tension devices with friction discs, the smooth relationship is. preferably, pressed into a receiving bore of the tubular extension forming part of the base piece. The plain bearing rests against the envelope surface of the stud connected to the support member

by the sliding layer.

  In addition, the invention also extends to the axial bearing or the friction lining, interposed between the pivoting part and the solid component in rotation of the tensioning device and comprising a base part and a support element. A metallic and / or electrical and / or galvanic separation between the base piece and the support member can also

  to be realized according to the invention by the axial bearing or the friction lining.

  For this, the metal support material of the axial bearing or the friction lining carries an insulating sliding layer. Preferably, the support material of the preferably disc-shaped support body is galvanically coated with a smooth insulating layer. In the new state or to a certain state of wear, the sliding layer prevents the passage of current through the axial bearing or the friction lining and thus cuts off the electrical circuit or the passage of the

  current between the base piece and the support member.

  In order to create a metallic or galvanic and / or electrical separation between the base piece and the support member, the invention provides an isolated or decoupled support and a torsion spring bearing attachment.

  on at least one part, namely the base part or the support element.

  Preferably, one end of the torsion spring is sheathed or is pressed and locked against the base piece via a

  insulating washer or against the support element.

  The construction of the tensioning device according to the invention in globe various electrical connections. It is interesting to link the

  base piece to the mass of the internal combustion engine or that of the

  vehicle. The electrical contact of the support element is then connected to a power supply of the internal combustion engine of the vehicle. Alternatively, the invention also provides an inverted electrical connection s according to which the base piece is connected by the electrical contact to the power supply of the internal combustion engine or the vehicle and between the support member and the mass of the engine. or the vehicle we have

the other electrical connection.

  The wear indicator according to the invention furthermore comprises an electrical circuit which, when closed, generates an acoustic signal.

and / or optical.

  The structure according to the invention thus functions as

  switch for which a part, namely the base part or the support element, is connected by the electrical contact to the power supply of the vehicle and the other corresponding part is connected by the electrical contact to the vehicle ground . In case of wear of the plain bearing, of a partially damaged sliding layer, the contact between the base part and

  the support member closes and thereby triggers a signal.

  According to another development of the invention, the intensity of the

  o signal depends on the intensity of the current, that is, on the electrical resistance

  the slip layer. This means makes it possible, for example, when the internal combustion engine is maintained, to apply a higher voltage to the sliding bearing to trigger, for example, an already weak signal for a reduced sliding layer thickness. In addition, it is interesting to determine the thickness of the slip layer present with a

  field of characteristics according to the intensity of the current and the

  which is established, with an indication of the period of use

  the plain bearing. The specialized maintenance personnel can thus determine when the smooth bearing or the device must be changed.

tensioner.

  Drawings The present invention will be described hereinafter more

  two examples of embodiments shown in the drawings.

  in which: 3s - Figure 1 shows an eccentric tensioning device according to the invention; - Figure 2 shows the support member or eccentric in longitudinal section, provided with the roller mounted rotatably; - Figure 3 shows the base of the eccentric tensioner device according to Figure 1; FIG. 4 shows a longitudinal section of a tensioning device with a friction pulley according to the invention;

  s - Figure 5 shows an electrical diagram.

  Detailed description of embodiments

  Figure 1 shows a longitudinal section of a tensioning device 1 in the form of an eccentric tensioning device. This device comprises a base 2 fixed integrally in rotation for example to the crankcase o of an internal combustion engine not shown in FIG.

  Figure 1. This base is also called base plate.

  The base 2 preferably made in the form of a part obtained by deep drawing, is a housing 3, staggered in the axial direction, receiving a collar pin 4, integrally rotated or rotatably mounted, to create an assembly. The flange stud 4 rotatably receives an eccentric support member 5. For this, the element of sup

  port 5 surrounds the collar stud 4.

  The support member 5 forms a rotational bearing 14 with the collar pin 4 of the base 2. To reduce friction, there is provided o between these parts, a sliding bearing 6 in an annular gap 7 delimited radially by a The friction bearing surface 4 of the support member 5 and the inner region of the support element 5. The friction bearing 6 in the receiving bore 15 of the supporting element 5 has on the outer side a metal support and is provided, on the inside: 5 in the direction of the envelope surface 16 of the base 2 or its collar stud 4, a lubricated layer 18. The sliding bearing 6 thus constitutes a blocking layer or a separation galvanic and / or electrical, metallic, not allowing the passage of the current of the base 2 towards the element of

  support 5 or in the reverse direction.

  A rolling bearing 8 mounted on the support member 5 rotates a rolling roller 9 against a traction means 10 such as a belt. To have support by the force of the roller 9 against the traction means 1O, there is provided a torsion spring 11 between the base 2 and the support member 5. The ends 12, ss 13 of the spring are blocked in rotation to the respective part. Beside a force component acting in the circumferential direction, the torsion spring 11 also generates a force acting in the axial direction on the support element 5. In order to reach a specific mounting position, it is necessary to block in position a support washer at one end of the collar pin 4, washer against which the support member 5 is supported

  through an axial bearing 23 disc-shaped.

  Another metal decoupling is provided between the torsion spring 11 and the base 2. The end 12 of the torsion spring 11 is supported by means of an insulating spring support 19 against the base 2. In such a way, corresponding, the base 2 and the support element 5 are each provided with a connection contact 20, 21. The connection contact 20 is connected to the positive pole of the internal combustion engine

  o or the power supply of the vehicle; the other branch contact-

  21 of the base 2 is connected to the mass of the internal combustion engine

  dull or vehicle. During operation if the plain bearing is intact, there is no current flow. An incandescent lamp installed between the connection contacts 20, 21 will not light in

these conditions.

  If the smooth layer 18 of the plain bearing 6 is damaged, there is

  closing the contact and the passage of the current triggers a flash signal.

the light bulb.

  Figures 2 and 3 show the different parts of the tensioner device 1 described above. These figures show in particular the structure of the friction bearing 6 in the receiving bore 15 of the support member 5 establishing a metallic contact between the support material 17 of the sliding bearing 6 and the support element 5. The slip 18 applied on the inner side, in particular galvanically on the support element 5 forms a metallic separation or an electrical blocking layer between the support member 5 and the bearing

  smooth 6 on the one hand and the collar stud 4 and the base 2 on the other.

  FIG. 3 shows the spring support 19 in the assembled state

  a stepped segment of the base 2 and an annular edge resting on a substantial surface of the base 2. The spring support 19 preferably made of a very strong plastic material or any other material insulation ensures effective metal decoupling between the

  torsion spring 11 and base 2.

  Figure 4 shows the tensioner device 31 as ss friction disk tensioner device. This device comprises a base piece 32 in the form of a pot, fixedly mounted or fixed in rotation;

  this base piece 32 comprises at its center a tubular extension

  33 plane coming axially protruding. The tubular extension 33 serves to receive the support member 35 in the form of a pivoting arm. For it,

  the tubular element 33 receives a collar pin 34 of the element

  port 35; the assembly is done in rotation thanks to a plain bearing 36.

  The free end of the support member 35 in the form of a pivoting arm s comprises a rotary rolling roller, not shown in FIG.

  roller is supported by force against the traction means. The torrent spring

  sion 41 makes it possible to pivot the support element 35 in a prestressing position for the traction element; this torsion spring is pressed both between the base piece 32 and the support member 35 by exerting an opening force resulting in a twisting force acting in

  the peripheral direction on the support member 35.

  The tubular extension 33 of the base piece 32 forms

  with the collar pin 34 of the support member 35 the rotation bearing

  44; an annular gap 37 delimited radially by the receiving hole 45 of the tubular extension 33 and the envelope surface 46 of the flange stud 34, receives the plain bearing 36. The plain bearing 36 is flanged in the receiving hole 45 with the material support 47 and builds

  by the sliding layer 48 against the collar stud 34.

  To support the axial force exerted by the toroidal spring 41 on the support member 35, the collar stud 34 is provided with one side of a sliding washer 38 abutting via a

  friction bearing 39 against the wall 40 of the base piece 33.

  metal strip between the base piece 33 and the support member 35 is by spring supports 49 receiving the ends 42, 43 of the spring

  torsion 41. The spring supports 49 preferably made of one

  high-strength plastics not only ensure decoupling

  effective metal but also some guidance of the torsion spring.

  41. The plain bearing 36 allows another metallic, electrical separation.

  that and / or galvanic. The sliding layer 48 applied as

  galvanic coating on bearing material 47 of sliding bearing 36

  a metallic, electrical and / or galvanic separation between

  Longitudinal tubular 33 and the collar pin 34 and thus between the base member 32 and the support member 35. The tensioning device 31 further comprises electrical branch contacts 50, 51. For this, ss the element of support 35 is provided with a branch contact 50 provided

  on the sliding washer 38 and the base piece 32 comprises a

electrical connection tact 51.

  FIG. 5 shows a diagram for determining the thickness of the layer or the state of wear of the sliding bearing 6, 36. The block diagram transposed to the tensioning device 31 of FIG. 4 shows that the electrical connection contact 50 connected to the support member 35 is connected to the positive pole of the electric vehicle and the base piece 32

  is connected by the electrical connection contact 51 to the ground of the motor.

  internal combustion engine or vehicle. When the plain bearing 36 is

  new, there can be no current flow between

  50, 51 so that no signal 52 will be triggered. If the sliding layer 48 of the sliding bearing 36 is damaged, the contact will close

  and allow the passage of a current between the branch contacts-

  50, 51 which triggers a signal 52. This function can be used

  as an effective means of indicating wear.

NOMENCLATURE

  1. Tensioning device 2. Basic part 3. Housing 4. Stud bolt 5. Support element 6. Flange bearing 7. Annular gap 0 8. Rolling bearing 9. Roller 10. Tensile means 11. Spring twist 12. Spring end lS 13. Spring end 14. Rotation bearing 15. Receiving drilling 16. Shell surface 17. Support material 18. Sliding layer 19. Spring support 20. Connection contact 21. Contact connection 22. Supporting disc 23. Axial bearing 31. Tensioning device 32. Basic part 33. Tubular extension 34. Collar bolt 35. Support element 36. Flange bearing 37. Annular gap 38. Slip washer 3s 39 Friction lining 40. Wall 41. Torsion spring 42. Spring end 43. Spring end 44. Rotating bearing 45. Receiving drilling 46. Casing surface 47. Support material 48. Slide layer 49. Support spring 50. Branch contact 51. Contact t connection lo 52. Signal

Claims (9)

CLAIMS CATI ONS   1) Tensioning device for a traction drive means of an internal combustion engine, characterized in that   s - the tensioning device (1, 31) comprises a fixed base part (2, 32)   connected by a rotational bearing (14, 44) to a support member (5, 35) pivotally mounted on the base member (2, 32) and said support member (5, 35)   ) comprises a roller (9) guided against a trac-   tion (10); a torsion spring (11, 41) interposed between the base piece (2, 32) and the support member (5, 35) provides support by the force of the roller (9) against the traction (10); - an annular gap (7, 37) delimited radially by the base piece (2, 32) and the support member (5, 35) receives a plain bearing (6, 36); s - the plain bearing (6, 36) provides at least one metallic or electrical and / or galvanic separation between the base piece (2, 32) and the support member (5, 35); - both the base part (2, 32) and the support element (5, 35) have an electrical connection contact (20, 21; 50, 51) and the damage to the plain bearing (6, 36) allows the passage of the current   between the base piece (2, 32) and the support member (5, 35).   2) Tensioning device according to claim 1, characterized in that it comprises a support member (35) in the form of a pivoting arm whose stud bolt (34) or the hub cooperates with a tubular extension or stud cylindrical , and the roller (9) is provided at   the free end of the support element (35) in the form of a pivoting arm.   3) Tensioning device according to claim 1, characterized in that it comprises a support member (5) in the form of an eccentric surrounding   concentrically the base part (2) and whose envelope surface   it rotates the roller (9).   3s 4) Tensioning device according to claim 1, characterized in that the bearing (6, 36) comprises a metal support element (17, 47) re   covered on one side with an insulating sliding layer (18, 48).    Tensioning device according to claim 1, characterized in that the plain bearing (6) is engaged in a receiving bore (15) of the element support (5).   6) tensioner device according to claim 1, o characterized in that its sliding bearing (36) is engaged in the receiving bore (45) of the prolon   tubular housing (33) integral with the base piece (32).   7) tensioner device according to claim 1, S characterized in that between a pivoting part and a fixed part in rotation of the tensor device (1) there is provided an axial bearing (23) or an installation   damping device in the form of a friction coating (39).   8) Tensioning device according to claim 7, characterized in that the axial bearing (23) or the friction lining (39) comprises a metal support material coated on one side with an insulating sliding layer. 9) Tensioning device according to claim 1, characterized in that at least one spring end (12, 13) of the torsion spring (11, 41) is decoupled or metallically insulated from the base piece (2, 32) or the support element (5, 35) against which it rests and is locked in position. Tensioning device according to claim 1, characterized in that ss the electrical connection contact (20, 21; 50, 51) of the base piece (2, 32) or the support member (5, 35) is connected to the mass of the mo   internal combustion engine or vehicle.   11) Tensioning device according to claim 1, characterized in that the electrical connection contact (20, 21; 50, 51) of the base piece (2, 32) or the support element (5, 35) is connected to food   s electric motor of the internal combustion engine or vehicle.   12) tensioner device according to claim 1, characterized in that an electric circuit closed by the electrical connection is made by the   o plain bearing (6, 36) triggers an acoustic or optical signal (52).   13) Tensioning device according to claim 12, characterized in that an electrical resistance defined by the sliding layer (18, 48) of the sliding bearing (6, 36) influences a certain intensity of the signal (52).