FR2633689A1 - VOLTAGE DEVICE, IN PARTICULAR FOR AUTOMOTIVE VEHICLE DISTRIBUTION BELTS - Google Patents

Abstract

This tensioning device comprises a first cylindrical member 10 firmly fixed to a fixed part 11, a movable eccentric member 13 and 16 in the form of a cylinder mounted to rotate and eccentric around the first member, a one-way clutch 14 being interposed between them. ci, and an idle roller 20 in the form of a hollow cylinder rotatably mounted around the movable eccentric member to urge the latter so as to push the idler roller against a belt 25. The one-way clutch allows the eccentric member to rotate. so as to push the idle roller against the belt, but prevents it from turning so as to move said idle roller away from said belt. Application in particular to tensioners for distribution belts installed on motor vehicle engines.

Description

t tensioning device, particularly for timing belts

  The present invention relates to a device for

  voltage for drive-type drive members

  rolling, for example belts and chains, and more particularly a tensioning device or tensioner for applying a specified tension for example to a timing belt wrapped around a pulley located on the crankshaft of a motor vehicle engine and a pulley

  located on the camshaft of this engine.

  The timing belt has a provision

  tensioner or tensioner comprising an idler roller which is

  pushed against the belt under the force of a spring of

  to apply a specified force of tension to the cour-

  while absorbing belt elongation due to changes in engine temperature or elongation

the belt in use.

  Among such belt tensioners, hitherto known, one of them includes a pivot fixed to an engine or

  a fixed analogous part, and a rotatably mounted arm on the

  vot and having a crazy roller rotatably mounted on its end

  front and spring loaded in a direction such that it pushes the idler against the belt (see US N

4,601,683).

  However, the conventional belt tensioner

  relatively large size, requires a

  consequently for its installation and is difficult to

  nipulate since the idler roller is mounted on the end

  front tee of the arm which is movable around the pivot.

  Such belt tensioners comprise a -amor-

  hydraulic weaver to suppress the resonance of the

  idler roller due to the vibration of the belt or motor. nevertheless

  minus the belt tensioner equipped with the hydraulic damper

  lique allows oil leakage and therefore

  oil creasing and this tensioner is a difficult maintenance.

  In addition, the hydraulic damper is of a

plex and is expensive.

  The main purpose of the present invention is

  to provide a tensioner for a belt, a chain or ana-

  logue, which is simple and inexpensive, compact and therefore easy to handle and can be

taller in a small space.

  The tensioner according to the present invention

  carries a solid cylindrical fixed member to be firmly attached to a fixed portion, a movable eccentric member in the form of a solid solid and rotatably mounted

  around the mobile eccentric element so as to come into

  tact with a drive member of a winding connector

  and a spring installed between the fixed part and the

  eccentric mobile in order to solicit the latter in

  a direction in which he pushes the idle roller in con-

  tact with the driver of the winding connectors

  high-viscosity oil is inserted into a

  pace between the outer perimeter of the fixed element

  and the inner periphery of the movable eccentric element.

  The tensioner according to the present invention may have a constitution picked up in its entirety, be easy to handle and be installed in a reduced space being

  given that the moving eccentric element and the idler are

  placed around the fixed element and furthermore because the high-viscosity oil inserted between the fixed element and

  the eccentric element provides the damping function. The Hui

  the high viscosity which acts by its viscous resistance so as to reduce vibrations, allows the tensioner to have a stable operation over an extended period of time,

  while the arrangement, in which the oil is provided simply

  in the space defined by the outer circumference of

  the fixed element and the inner circumference of the outer element

  very simple, inexpensive and free from oil leakage,

  which therefore guarantees easier maintenance.

  Other features and advantages of the pre-

  invention will be apparent from the description given hereinafter

  reference is made to the accompanying drawings, in which:

  FIG. 1 represents a cross sectional view

  versale, taken along the line I-I in Figure 2 and

  trant a first form of. production of a belt tensioner according to the invention; FIG. 2 is a view in longitudinal section taken along line II-II and in FIG.

  FIG. 3 is a view of the embodiment of

  as seen in the direction of the arrows III-III in Figure 2;

  FIG. 4 represents a cross sectional view

  versale taken along the line IV-IV in Figure 2;

  FIG. 5 represents a cross sectional view

  versale taken along line V-V in Figure 6 and showing

  another belt tensioner according to a second form of

  embodiment of the present invention; - Figure 6 is a longitudinal sectional view taken along the line VI-VI in Figure 5; FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6; FIG. 8 is a longitudinal sectional view taken along the line VIII-VIII in FIG. 9 and showing another belt tensioner corresponding to a third embodiment of the invention; Fig. 9 is a cross-sectional view taken along line IX-IX in Fig. 8; Fig. 10 is a cross-sectional view taken along the line X-X in Fig. 11 and showing another belt tensioner corresponding to a fourth embodiment of the invention;

  FIG. 11 is a longitudinal sectional view

  taken along the line XI-XI in Figure 10; - Figure 12 is a view of the tensioner seen in the direction of the arrows XII-XII in Figure 11; and - Figure 13 is a cross-sectional view

  taken along line XIII-XIII in Figure 11.

  With reference to the accompanying drawings, the present invention will be described below as it is intended for the motor vehicle timing belt.

  Figures 1 to 4 represent a first

  realization. The belt tensioner corresponding to the first embodiment is attached to a fixed part (i.e., the bloccylinders) 11 of an engine by means of a

  fixed rod made in the form of a bolt.

  One end of the fixed rod 10 has a

  threaded part lob with a slightly lower outer diameter

  it has a flange 10c and a head 10d, which are integral with each other. A side plate 12 in the form of an annular disc having substantially the same outer diameter as the flange 10c is force-fitted on the threaded portion lob of the fixed rod 10. The fixed rod 10 is fixed to the part

  fixed 11 with the threaded portion lob screwed into the

  11, which has the effect that the side plate 12 is

  by clamping between the full cylindrical part 10a of

the rod and the fixed part 11.

  A hollow cylindrical intermediate member 13, which is slightly shorter than the cylindrical portion 10a and has an outer diameter smaller than that of the flange 10c of the side plate 12, is provided around the

  full cylindrical portion 10a, concentrically to this

  while a unidirectional clutch 14 is interposed

  between the cylindrical portion 10a and the element 13. The element

  insert 13 has, at one of its

  in the direction of the flange 10c, an inner diameter of

  significantly greater than the outside diameter of the cylindrical part

  10a of the fixed rod 10. The other part of the element

  13 has an inside diameter greater than this diameter

  TER AL. A sleeve 15 is inserted in the intermediate element

  13 around the cylindrical portion 10a so as to be

  at the side plate 12. In the middle of the solid cylindrical portion 10a of the rod, the unidirectional clutch 14 is disengaged

  placed in an annular space between the cylindrical part

  10a and the intermediate element 13. The unidirectional clutch

  14, which is for example a known unidirectional clutch roller, is disengaged when the intermediate member 13 rotates counterclockwise on the

  FIG. 1 with respect to the fixed rod 10, which allows the rotation

  in the opposite direction of the clock, but is

  when the element 13 turns in the direction of the

  a clock in Figure 1 so as to lock

element 13.

  A movable eccentric element 16 in the form of a solid short cylinder having the same length as the intermediate element 13 is rotatably mounted in position

  eccentric, around the intermediate element.

  centered 16 has an eccentric bore 17 in which

  The space between the outer periphery of the intermediate member 13 and the inner periphery, which defines the bore, of the eccentric member 16 is minimized. Silicone oil O, having for example a viscosity equal to 100,000 cSt (25 C), is inserted into said space so as to apply an increased torque to the eccentric member 16. The rotation torque, which depend on

  the viscosity of the oil O is also determined on the basis of

  the outer diameter and the length of the

  tercalaire 13 and the dimensions of the space between the

  13 and the eccentric element 16. O-rings 18 and 19 are interposed between these elements 13 and 16 at their respective ends so as to confine the oil

in said space.

  A hollow hollow cylindrical roller 20 disposed around the eccentric element 16 by means of the interposed mounting of a

  plurality of spherical rolling members 21, is mounted

  tative, but can hardly move in the axial direction. The eccentric element 16 comprises, in the vicinity of

  the side plate 12, a boss 16a substantially concentric

  only to the fixed rod 10. A helical tension spring 22 is mounted around the boss 16a and one of its ends 22a is hooked to a stud 23 fixed to a stepped portion 16c

  the eccentric element 16, said part 16c being located

  be the boss and an eccentric portion 16b of the element 16.

  The other end 22b of the spring is hooked to a stud 24 fixed on the fixed part 11. The spring 22 biases the eccentric element 16 in a counterclockwise direction in FIG. 1, pushing the idler 20 against a face

  of the timing belt 25, which is located at the opposite

  on the other side of the belt having teeth 26.

  The eccentric portion 16b of the offset element

  16 has a hole 27 for insertion of a pin, this drilling.

  extending axially through the eccentric portion. Before

  To attach the belt tensioner to the motor, insert a gou-

  assembly pin 28 in the bore 27, from the side facing the flange (10c). The assembly pin 28, which protrudes from the stepped portion 16c of the element 16, is disposed outside the boss 16a, and the end 22b of the spring 22 intended to apply contreletétn24 located on the fixed part 11 is hooked on the assembly pin 28. In this state, the force of the spring 22 is adjusted to a

appropriate value.

  Once the fixed rod 10 and the side plate

  12 have been fixed to the fixed part 11 in this

  shown in FIG. 2, the assembly pin 28 is removed from the eccentric element 16. The end 22b of the spring is hooked onto the pin 24 located on the fixed part 11,

  which makes it easy to set up the turnbuckle

ROIE.

  If the belt 25 suddenly relaxes, for example

  due to a rapid acceleration of the motor, the eccentric member 16 is pushed counterclockwise in FIG. 1 by the action of the spring 22, the intermediate element 13 also acting turning in the same direction under the effect of resistance

  viscous oil O. Since the clutch unidirectional

  14 is disengaged, which allows the rotation of the intermediate element 13 in this direction, the eccentric element 16 rotates rapidly in concert with the intermediate element 13 in the opposite direction of clockwise in FIG. which causes the idler 20 to rapidly follow the expansion of the belt 25 by being pushed against said belt, which in turn is kept in the tensioned condition as specified. This eliminates the possibility that some teeth

  the belt does not mesh with the element concerned. Conversely

  when the tension is established as a result of the contrac-

  of the belt 25, the eccentric element 16 acts in rotation

  clockwise in the figure

  1 against the force of the spring 22, and the inter-

  calaire 13 also acts by turning in the same direction, given the viscous resistance of the O oil.

  the one-way clutch 14 engages in such a way as to

  fishing the rotation of the intermediate element 13 in this direction so that the eccentric element 16 rotates only

  slightly clockwise on the bottom of the

  1 against the viscous resistance of the oil O, which slowly displaces the idler roll 20 until the

  the tension of the belt 25 decreases to the specific value

  fied. The vibration of the idler roller 20 due to the vibration of the belt 25 and to the vibration of the engine, is reduced by the

  viscous resistance of O-silicone oil acting at the

against rotation.

  Therefore, the viscous resistance of the silicone oil has a cushioning effect, which ensures that the tensioner has stable performance for an extended period of time without the need to perform a

  new oil filling. The tensioner is of a construction

  very simple and compact, inexpensive and can be

in a small space.

  Silicone oil O can be inserted into the

  between the intermediate element 13 and the outer element

  centered 16 by applying this oil on the outer periphery of the intermediate element 13 or on the inner periphery of the eccentric element 16 or both on these two elements, and then assemble these two elements to one another . We can

  also easily obtain a silico-oil

  in the entire space provided, by arranging a small

  the helical groove or small axial grooves in the

  outside tower of the intermediate element 13 or in the

  defining the inner periphery of the eccentric member 16, inserting the oil into the groove (s) and

  turn the eccentric element 16 as it is mounted

  It is also possible for the outer periphery of the intermediate element 13 or the inner periphery of the eccentric element 16 to retain the oil.

  silicone in an annular groove in said

these elements.

  In the case of the belt tensioner indicated above, the threaded portion 10b of the fixed rod 10 comprises a dextrorsum thread, and the direction in which the threaded element 10b is tightened is in agreement with the direction of rotation (direction

  clockwise in Figure 1) of the ex-

  centered 16 when the belt 25 is tensioned. By con-

  when the belt tension increases, the embro-

  The unidirectional yage 14 engages as has already been

  diqué, by subjecting the fixed rod 10 to a torque acting to further tighten the rod. Conversely, when

  the tension of the belt 25 decreases, the unidirectional clutch

  14 is disengaged, which frees the rod 10 of the couple

  acting in the direction of loosening of this rod. By con-

  There is no risk that the fixed rod 10 will loosen during use. Furthermore, since the clutch 14 is engaged under the effect of the rotation of the eccentric element 16 and the intermediate element 13 in the direction

  to tighten the fixed rod 10 while maintaining this

  in a fixed state, the clutch 14 is disengaged by rotation

  tation of the fixed rod 10 in the tightening direction, the elem-

  eccentric 16 and the intermediate element 13 being maintained in a fixed state. That's why we can easily

  place the tensioner by rotating the single fixed rod 10-

in the direction of tightening.

  Figures 5 to 7 show a second form of

production.

  A staggered fixed rod 31 is. fixed at the level of

  its base end 31a, at a fixed part 30 of a motor.

  A cylindrical intermediate element 33 is provided around a solid intermediate cylindrical portion 31b of the fixed rod

  31, with the interposed mounting of a unidirectional clutch

  32 between these elements. Like the clutch 14 of the first

  In the first embodiment, the clutch 32 allows the intermediate member 33 to turn counterclockwise in FIG. 5 relative to the fixed rod 31, but

  prevents a clockwise rotation of a

  33 of the element in Figure 5. An eccentric element 34

  in the form of a short solid cylinder is rotatably mounted

  tif, in eccentric position, around the intermediate element

  33. This element 33 is mounted in an eccentric piercing 35

  floated in the eccentric element 34. As in the case of the first

  In the first embodiment, silicone oil O is

  troduced in a space between the outer perimeter

  of the intermediate element 33 and the inner circumference defined

  the eccentric holes 35 of element 34. The

  sides 366 and 37 each having the shape of a

  -que ring are attached to the respective end faces

  of the intermediate element 33 and concentrically to the latter.

  The side plates 36,37 have an inside diameter

  slightly greater than the outer diameter of the cy-

  intercalary lindrique 31b of the rod 31 and have a diameter

  outside superior to that of the intermediate element 33.

  The eccentric element 34 has a length equal to that of the intermediate element 33. The elements of the end faces

  opposite of the eccentric element 34, close to the inner circumference

  of this element, are in contact with the elements of

  inner surface of the respective side plates 36,37

  their outer perimeters. O-rings 38,

  39,40,41 used to house the oil O are inserted into the

  these opposite ends of the intermediate element 33 and

  the eccentric element 34 so as to be applied by compres-

  against the side plates 36,37. As in the case of the first embodiment, a cylindrical idler roller

  hollow 42 is provided around the concentric element 34,

  the interposed mounting of a plurality of

  The impeller 42 is rotatably mounted, but can have almost no axial displacement. A collar 44 is mounted on a stepped portion between the cylindrical member

  intermediate 31b of the rod 31 and a threaded portion 31c

  at the upper end of the stem, and is fixed by a

  nut 45 screwed onto the threaded portion 31c. Lateral plates

  36,37 are maintained at the level of their peripheral

  between the collar 44 and a stepped portion between the cylindrical portion 31b of the rod 31 and the end

  base 31a of this rod, which keeps the assembly

  almost axially immobile. A helical spring of

  46 is mounted around the base end portion 31a of the fixed pin 31, and its opposite ends 46a, 46b are respectively attached to the eccentric member 34 and to the fixed portion 30. The spring 46 urges the member eccentric 34 counterclockwise in the figure, pushing the idler roller 42 against the face of the belt

  -47, located opposite the face of this cour-

with teeth 48.

  The belt tensioner according to the second form

  realization works the same way as that of

the first embodiment.

  Figures 8 and 9 show a third form

of realization.

  Two fixed elements 51, 52, each having the shape of a stepped cylinder, are fixed concentrically to one

  fixed part 50 of an engine by means of a fixed rod 53

  in the form of a bolt. One end of the first of the fixed elements, namely 51, has an adjacent flange 51a

  at the fixed part 50, while its other end

  a part 51c of small diameter. Between the flange 51a and the small diameter portion 51c, the stationary member 51 has an element 51b for supporting a spacer element, which has an intermediate outer diameterincluded between the outside diameters of the flange and the portion 51c. The portion 51c of small diameter extends towards the leading end of the fixed rod 53 and is mounted in the second fixed element 52. At one of its ends, the second element

  fixed 52 has a flange 52a which is adjacent to the end

  The head of the fixed rod 53. The part of the element 52 forms a support portion 52b of the intermediate element, which has the same diameter as the support portion 51b of the

  fixed element 51. Around the small diameter part

  51c of the first fixed element 51 is provided a groove

  annular ring 57 located between the support portions 51b, 52b

  of the two fixed elements 51,52. An intermediate element 55 pos-

  sedant the shape of a hollow cylinder having a diameter

* Outside lower than that of the flanges 51a, 52a, is provided

  round support parts 51b, 52b and is concentric to these

  latest. As in the case of the first form of reali-

  tion, a one-way clutch 56 is arranged in the

  annular groove 54 so as to allow the inter-

  55 to turn clockwise on FIG. 9 relative to the fixed elements 51, 52, but

  by preventing the rotation of these elements in the opposite direction.

  A movable eccentric element 57 in the form of a

  short cylinder is rotatably and eccentrically mounted around the

  55. Silicone oil O is inserted

  in a space between the outer circumference of the

  55 and the inner perimeter of the element

  eccentric 57, which defines the eccentric drilling 58 of this element.

  is lying. O-rings 59,60 for confining the oil

  O, are interposed between the intermediate element 55 and the element

  eccentrically 57, at their opposite ends. A hollow cylindrical hollow roller 61 carries a plurality of elements

  spherical bearings 61 arranged around the element

  57 so as to be interposed between this element and the

  roller. The eccentric element 57 has at its end

  close to the fixed part 50, a boss 57a around which

  a torsion spring 63 is provided.

  63a of the spring 63 engages around a first pin 64 fixed in a stepped portion 57c of the eccentric element 57,

  while its other end 63b is hooked on a

  your 65 stuck in the fixed part 50. The spring 63 is bent,

  at its end near the end 63a, and the

  tie rod 63c engages around a second nipple 66 anchored in

  the stepped portion 57c of the eccentric member 57, and that of a

  the end of the nipple 66 situated opposite the side where the end 63a is hooked on the first nipple 64, the second nipple 66 thus being adapted to support the reaction to be

  exerted by the first nipple 64. The spring 63 requests the ele-

  eccentrically 57 in a clockwise direction in FIG. 9 so as to push the idler 61 against the

timing belt 69.

  In the absence of the second nipple 66, the reaction

  picking from the first nipple pushes the spring 63 against

  the boss 57a of the eccentric element 57, possibly hindering

  a uniform rotation of the eccentric element 57, while

  that in the case of this embodiment, the se-

  cond teton 56 supports the reaction exerted from the first

  first nipple 64, which eliminates the risk that the spring 63 is pushed back against the boss 57a and consequently guarantees

  a uniform rotation of the eccentric element 57.

  Before attaching the belt tensioner to the motor, an assembly pin 68 is inserted into a hole 67 formed in the eccentric portion 57b of the eccentric element.

  and hooking the end 63b of the spring to be hooked

  at pin 65 located on the fixed part 50, on the pin

  assembly 68, as in the first embodiment.

  The belt tensioner of the third embodiment is assembled and operates in the same manner as

  in the case of the first embodiment.

  In the case of the three embodiments

  cedente, the intermediate element is arranged around the stem

  fixed by means of the interposed mounting of a unidirectional clutch

  between said element and the rod, and the movable eccentric element is mounted around the intermediate element

  the interposition of a silicone oil. Otherwise the ex-element

  centered mobile can be mounted around the fixed rod or a cylindrical member mounted fixed around the fixed rod, with application of a silicone oil on the inner periphery

of the eccentric element.

  FIGS. 10 to 13 represent such an embodiment, which constitutes a fourth form of embodiment

tion.

  A solid cylindrical fixed element 71 and

  sides 72,73 attached to the respective ends of

  71 and each having the shape of an annular disk.

  are fixed concentrically to a fixed portion 70 of a motor by means of a threaded rod 74 having the form of a bolt. A movable eccentric element 75 having the shape of a

  full cylinder is rotatably mounted and in the

  around the fixed member 71. Silicone oil is introduced into a space between the outer periphery of the fixed member 71 and the inner surface of the eccentric member 75 defining an eccentric bore 76. sealing 77,78 for confining the oil O are provided between the fixed element 71 and the eccentric element 75,

  from their respective opposite ends. A roller idler cylin-

  hollow gauge 79 is provided around the eccentric element 75,

  by interposing a plurality of spherical elements

  80. The eccentric element 75 has a bos-

  wise 75a which is closer to the fixed member 70 and around which is installed a helical torsion spring 81. The spring 81 has an end 81a attached to a

  first nipple 82 anchored in a stepped portion 75c of the element

  eccentric 75, a bent portion 81c near the end

  81a and applying against a second nipple 83 attached to the

  step 75c, while the other end 81b is

  on a pin 84 fixed in the fixed part 70. The spring

  71 urges the eccentric element 75 in the opposite direction of the

  guilles of a watch in figure 10, pushing the pebble

  79 against a timing belt 89.

  The side plate 73, located in the vicinity of the head end of the fixed rod 74, has a portion

  large diameter 73a over at least half of its circumference

  and a small diameter part corresponding to 73b

  proximally to the other half of the circumference. A R-

  As a limit stop 85 is attached to the end face.

  of an eccentric part 75b of the element 75 and is

  outside the small diameter portion 73b, but within the large diameter portion 73a. The range of rotation of the eccentric member 75 is limited by the contact of the pin 85 and the large diameter portion 73a. Cutting

  semicircular 86 is formed in the peripheral edge ex-

  of the large diameter portion 73a of the side plate

  line 73, while a hole 87 for insertion of the nipple, corre-

  at the cut 86, extends in the eccentric portion 75b

of element 75.

  Before attaching the belt tensioner to the motor, an assembly pin 88 is inserted into the cutout 86 of the side plate 73 and inserted into the bore 87 of the eccentric member 75, and the end 81b is hooked on. spring 81 which must be hooked on the stud 84 located on

  the fixed part 70, around the assembly pin 88.

  The belt tensioner of the fourth embodiment is similar to that of the third embodiment both from the point of view of the mounting procedure

  operation, except that it does not contain any embra-

unidirectional yage.

  The tensioners according to the invention may be

  be used for belts and chains other than timing belts for

motor vehicles.

Claims (3)

  1. A tensioning device characterized in that it comprises a   first cylindrical element (10) to be firmly attached to a   fixed element (11), a movable eccentric element (13 and 16) in the form of a cylinder and mounted in an eccentric position around the first element (10), a unidirectional clutch (14) being interposed therebetween, and an idler roller (20); realized in the form of a hollow cylinder and rotatably mounted around the movable eccentric element (13 and 16) solicitor the latter in a direction such that it pushes the idler roller (20) against a drive member forming a connection winding (25), the clutch   unidirectional (14) allowing the eccentric element (13 and 16) to rotate   in such a way that it repels the idler (20) against the organ   forming a winding connection (25), but prevents the   eccentric (13 and 16) to rotate in such a way that it spreads the   idler roller (20) of the drive member forming a winding connection ment (25).   2. Voltage device according to claim 1, characterized   characterized in that the movable eccentric element (13 and 16) comprises a cylindrical intermediate element (13) mounted by virtue of the unidirectional clutch (14) on the outer circumference of the first cylindrical element (10) and a cylindrical outer eccentric element ( 16) mounted eccentrically and rotatably on the outer portion of the intermediate member (13), vibration damping means (0) being interposed between the outer eccentric member (16) and the intermediate member ( 13)   in order to damp the vibration of the training member forming a link   by winding (25), while a spring (22) is provided between the fixed part (11) and the outer eccentric element (16) to request the   idler (20), in such a way that it pushes the latter against the   winding connection drive shaft (25).   3. Voltage device according to claim 2, characterized   in that the vibration damping means (0) is a high viscosity oil interposed between the outer periphery of the intermediate element   (13) and the inner periphery of the outer eccentric member (16).