FR2511101A1 - DISC BRAKE TRIM WEAR DETECTOR - Google Patents

Abstract

THIS WEAR DETECTOR 24 INCLUDES A SHEET PLATE 26 WHICH IS MAINTAINED APPLIED AGAINST A SURFACE OF THE PLATE 14 WHICH IS OPPOSITE THE SURFACE OF THIS PLATE WHICH CARRIES THE BRAKE LINING 16, BY GUIDANCE PINS THAT ARE THREADED THROUGH ALIGNED OPENINGS OF PLATE 14 AND DETECTOR SHEET PLATE. THIS SHEET PLATE SHOWS AT LEAST ONE FINGER 30 WHICH TAKES BIRTH ON ONE OF ITS EDGES AND WHICH IS FOLDED IN RELATION TO THE GENERAL PLANE OF THE PLATE SO THAT ITS FREE END 32 IS IN A PLANE WHICH FORMES A OBTUS ANGLE WITH THE PLANE GENERAL OF THE PLATE AND IN A WAY THAT THIS FREE END COMES IN CONTACT WITH THE BRAKE DISC ON WHICH THE DETECTOR IS FITTED WHEN THE SEAL 16 HAS REACHED BY WEAR A THICKNESS AT WHICH IT SHOULD BE REPLACED.

Description

2511 10 1

  The present invention relates to detectors

  wear of disc brake linings and concerns in part

  special wear brake lining sensors

  with two opposite brake pads each of which

  one carries a brake lining arranged to attack a corresponding face of a brake disc mounted on a wheel of a motor vehicle when the brake pads are

  move the detectors closer to the disc, creating a sound signal

  re when a brake lining needs to be replaced.

  We know in disc brakes wear sensors of the linings in which one of the pads

  disc brake has a protrusion formed on its plate

  as basic and directed towards the brake disc, the height of the projection being such that the contact between the projection

  and the disc occurs when the pad lining

  quette reaches a thickness at which it must wear

  be replaced When contact is established between the sail-

  binds and the disc, this contact manifests itself to the driver of the vehicle by the creation of a loud squeaking or squealing noise which is emitted by the brake when the brakes of the

  vehicle are tight Although effective in use

  In addition, these noise generating detectors cannot be manufactured in a simple manner in a form which makes it possible to produce noise of maximum intensity while reducing to a minimum the deterioration of the disc brake which results from the friction contact between the protrusion and

  the brake disc during noise production.

  A brake pad wear detector

  according to the invention, for a disc brake comprising two opposite pads each of which carries a brake lining arranged to attack a corresponding face of the disc mounted on a wheel of the motor vehicle when

  the brake pads approach the disc, these

  brake pads being suspended with the possibility of

  placing, respectively on both sides of the disc, on guide pins which extend transversely to

  the rim of the disc and being threaded through openings-

  res aligned corresponding pads'and said brake, comprises a sheet metal shim having openings which

  correspond to the openings of the guide pins

  dage of the brake pad and at least a finger-shaped part which projects on one edge of said shim and is folded down relative to the plane of the shim to occupy

  a position in which a free end of the par-

  folded tie lies in a plane which forms an ob-

  io with the plane of the wedge, each finger-shaped part being first folded down to form an acute angle with the plane of the wedge and the free end of this finger-shaped part being then folded in the direction opposite so that the finger-shaped part has a second bend formed in the region of its middle and the free end of the finger-shaped part crosses the corresponding edge of the shim so that, when the detector is mounted in the brake, said shim is placed in contact with a surface of one of the brake pads, which is opposite the surface which carries the lining, said guide pins extending through said shim openings and said free end passing very close to an edge of the corresponding lining,

  pointing towards the disc and extending over a distance

  predetermined tance which corresponds to the thickness of the gar-

  corresponding niture which remains when the garnish

request to be replaced.

  Being of a thin section, the part in the form of

  wedge finger which constitutes the sensor according to the invention

  tion, acts like a vibrating reed when the extreme

  free half of the shim comes into contact with the rotating disc

  during brake application The vibration generated

  in the finger-shaped part is transmitted to the whole

  ble through the shim to generate noise

  very pronounced characteristic that the driver of the vehicle

  it can easily be discerned from other engine noises.

  In a preferred embodiment of the invention

  tion the sheet metal shim has a finger-shaped part projecting from each of its two opposite edges so

  that, when the sensor is mounted in the brake, the ex-

  free hoppers of the folded parts extend very close

  along the opposite edges of the corresponding trim.

  This arrangement makes the shim universally applicable to the brakes in question in the sense that it works just as

  well when mounted in contact with one or the other

  be brake pads from the assembly.

  Since in the sheet metal shim of the wear detector each finger-shaped part is first folded down so as to form an acute angle relative to the plane of the shim and then the free end of the the finger-shaped part is folded in the opposite direction, so that the finger-shaped part has a second bend adjacent to its central part and that the free end of the finger-shaped part extends transversely to the edge of the shim, this shim placed against a corresponding brake pad, has each of its parts in

  finger shape arranged in a pick-up arrangement

  seated in the disc brake and practically without projection

  which may interfere with the operation and maintenance of the brake.

  In this way, the length and arrangement of each par-

  finger-shaped tie can be such that the tone

  and the amplitude of the noise generated are clearly different

  are those of noises at any other point in the

  motor vehicle during the movement of this vehicle.

  Other characteristics and advantages of the invention

  tion will appear during the description which follows.

  In the accompanying drawings, given solely by way of example, La Fiç 1 is a side view of a disc brake,

  with partial cut-outs to show a detector of

  disc brake lining according to the invention;

  Fig 2 is a side view of a detector

  disc brake lining according to the invention;

  Fig 3 is a sectional view of the detector

  packing wear shown in Fig 2, taken next

before line 3-3 of this figure;

  Fig 4 is a view of the wear detector

  niture of Fig 2, in position on a disc brake pad; and FIG. 5 is a sectional view of the disc brake pad and of the lining wear detector which are shown in FIG. 4, the view being taken according to the

line 5-5 of this figure.

  Fig 1 is a side view of a disc brake comprising two opposite brake pads 12, 14 each of which carries a brake lining 16 The disc brake comprises a body 18 which encloses a piston and cylinder assembly for actuation hydraulic brake and a

  stirrup part 20 which spans the disc (not shown

  felt) on which the disc brake is mounted It is provided

  in the portion 20 forming a stirrup, an opening through the

  which one can put the disc brake pads 12, 14 in place on either side of the disc The pads

  12, 14 of the disc brake are suspended so that

  see move, on guide pins 22 which extend

  stretch across the rim of the disc and pass through

  towards aligned openings made respectively in the pads 12, 14 of the disc brake and in the body

  18 as well as in the stirrup 20 The other work elements-

  disc brake lants are conventional and it is not

  necessary to give a more complete description for

to explain the invention.

  As can be seen in FIG. 1, part of the caliper 20 is torn off to reveal a wear detector 24 of the pads of disc brake pads according to the invention. As can be seen more clearly in FIGS. 2 and 3 of the drawings, the disc brake lining wear detector 24 comprises a sheet metal shim 26 having openings 28 and two finger-shaped parts 30 each protruding from a corresponding edge

  of the sheet metal shim 26 in a direction roughly parallel

  lele to a line which joins the axes of the openings 28 of this wedge 26 Each finger-shaped part 30 is first bent at its root to form an acute angle with the plane of the sheet metal wedge 26 The free end 32 of the finger-shaped part 30 is then folded back towards the plane of the wedge 26 to form an elbow in the part

  finger shape 30, in the middle region of this par-

  tie, the free end 32 of the finger-shaped part 30 lying in a plane which forms an obtuse angle close to the right angle with the plane of the wedge 26, as can be clearly seen in FIG. 3 To give the finger-shaped part 30 the appropriate desired length

  to make an optimum sound when it is brought into

  bration we make sure that the edges of the Yale 26 conver-

  gent towards each other as shown in Fig 2.

  In combination with the folding of each finger-shaped part 30, this arrangement has the effect that the parts 30 are arranged with a shape picked up in the brake in

which the wedge 26 is mounted.

  To mount the lining wear detector 24 in the brake 10, the sheet shim 26 is placed in contact with the face of the disc brake pad 14 which is

  opposite the face of this plate which carries the gar-

  niture 16, as indicated in Fig 5 of the

  sins We align the sheet metal shim 26 in position on the gar-

  niture 14 of the disc brake in such a way that the openings

  tures 28 of the sheet metal wedge coincide with openings

  34 of the disc brake pad 14.

  In this position, the free end portions 32 of

  30 finger-shaped parts take the positions re-

  shown in Figs 4 and 5, in which the free end portions 32 extend very close along the edges

  of the lining 16, extending over a pre-

  determined which corresponds to the thickness that the lining 16 will have when it must be replaced When the sheet metal shim 26 is mounted in position on the plate 14 of the

  disc brake, put the pad 14 and the shim 26 in position

  position in the opening of the stirrup 20 and these elements are retained in position by threading corresponding guide pins 22 through the aligned openings 28, 34

  formed respectively in the wedge 26 and in the plate-

brake te 14.

  As can be clearly seen in FIG. 5, the free ends 32 of the finger-shaped parts 30 are in contact neither with the edges of the wafer 14 nor with the lining 16 and, therefore, they are free

  vibrate if they are vibrated when the

  lining wear protector 24 is in position in the disc brake 10 and the brake pad linings are relatively little worn, the sensor 24 remains latent It does not interfere in any way with the normal operation of the brake

  disc 10 When the lining 16 carried by the plate-

  te 14 of the brake reached by wearing a thickness to which it should be replaced, the tightening of the pads 12, 14 on the disc has the effect that the free ends 32 of the finger-shaped parts 30 of the detector 24 enter

  in contact with the rotating disc during braking.

  The friction contact between the free ends 32 and the rotating disc is sufficient to put the parts

  shaped like a vibrating finger at a rate such as el-

  generate a loud noise, especially that is amplified

  trusted by the fact that the vibrations are transmitted to the main body of the sheet metal shim 26, which vibrates this shim between the brake pad 14 and the brake piston thus amplifying the noise-generated When he hears the particular noise generated by the vibrating contact of

  free ends 32 with the rotating disc, the conduc-

  the vehicle is warned that the trim on the pads

  your disc brakes need to be replaced During the replacement of worn linings with new linings, the wear sensor can be checked and reused if it is not excessively worn or, on the contrary

  replace it entirely with a new wear detector when

  that it shows obvious signs of wear.

  The brake pad lining wear detector according to the invention is an effective detector and

  compact, which is economical to manufacture, assemble and replace

  place in a disc brake The thickness of the shim and the length and arrangement of the finger-shaped parts can be chosen in advance so as to cause the detector to produce a sound having the tone, the amplitude

and the desired characteristic.

  The preferred embodiment of the invention described herein is not only quick and easy to install but, moreover, it is capable of universal application in the disc brake for

  which it is designed, in the sense that it can be

  tee on one or other of the linings 12 and 14, as

  Furthermore, since the overall cost of the

  tectors is low, a detector according to the invention can be mounted on each of the brake pads if this

seems desirable.

Claims (2)

CLAIMS -   1 Brake pad wear detector   only for a disc brake comprising two opposing pads   each of which carries a lining arranged to cooperate with a corresponding face of the brake disc mounted on a wheel of a motor vehicle when said brake pad approaches the disc, this wear detector   brake lining creating an audible signal when the   brake pad needs to be replaced, this detector being characterized in that said brake pads (12, 14)   are suspended with the possibility of moving, respectively-   ment on both sides of the disc, on guide pins (22) which extend transversely to the rim of the disc   and are threaded through corresponding aligned openings   of the pads (12, 14) and of said brake (10) the   detector comprising a sheet metal shim having openings   tures (28) which correspond to the openings of the guide pins of the brake pad and at least one finger-shaped part (30) which projects on an edge   of said wedge and is folded down relative to the plane of the ca-   the to occupy a position in which one end li-   bre (32) of the folded part is in a plane which forms an obtuse angle with the plane of the wedge, each finger-shaped part (30) being first folded down to   form an acute angle with the plane of the wedge (26) and the ex-   free end of this finger-shaped part then being folded in the opposite direction so that the part in   finger shape has a second bend formed in the re-   gion of its middle and that the free end (32) of the   finger-shaped tie crosses the corresponding edge of the   the (26) so that, when the detector (24) is mounted in the brake (10), the shim (26) is placed in contact with a surface of one of the brake pads, which is 1 '   opposite of the surface which carries the lining, said bro-   guide pins (22) extending through said openings   res (28) of the shim and said free end (32) passing 251 1101   very close to an edge of the corresponding lining, di-   rigging towards the disc and extending over a distance   this predetermined which corresponds to the thickness of the lining   re corresponding which remains when the packing needs to be replaced.   2 Brake pad wear detector   as claimed in claim 1, characterized in that the case   the sheet metal (16) has a finger-shaped part (30) projecting on each of its two opposite edges so that,   when the sensor (24) is mounted in the brake, the ex-   free hoppers (32) of the folded parts extend very   close along the opposite edges of the corresponding trim.