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GB2129511A - Shims for disc brake pads - Google Patents

Shims for disc brake pads Download PDF

Info

Publication number
GB2129511A
GB2129511A GB08329104A GB8329104A GB2129511A GB 2129511 A GB2129511 A GB 2129511A GB 08329104 A GB08329104 A GB 08329104A GB 8329104 A GB8329104 A GB 8329104A GB 2129511 A GB2129511 A GB 2129511A
Authority
GB
United Kingdom
Prior art keywords
shim
pad
piston
disc brake
fibres
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08329104A
Other versions
GB2129511B (en
GB8329104D0 (en
Inventor
Bernard Alban Rowbottom
Ronald Jeffe Wadsworth
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Federal Mogul Friction Products Ltd
Original Assignee
Ferodo Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ferodo Ltd filed Critical Ferodo Ltd
Priority to GB08329104A priority Critical patent/GB2129511B/en
Publication of GB8329104D0 publication Critical patent/GB8329104D0/en
Publication of GB2129511A publication Critical patent/GB2129511A/en
Application granted granted Critical
Publication of GB2129511B publication Critical patent/GB2129511B/en
Expired legal-status Critical Current

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16DCOUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D65/00Parts or details
    • F16D65/78Features relating to cooling
    • F16D65/84Features relating to cooling for disc brakes
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16DCOUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D65/00Parts or details
    • F16D65/02Braking members; Mounting thereof
    • F16D65/04Bands, shoes or pads; Pivots or supporting members therefor
    • F16D65/092Bands, shoes or pads; Pivots or supporting members therefor for axially-engaging brakes, e.g. disc brakes
    • F16D65/095Pivots or supporting members therefor
    • F16D65/097Resilient means interposed between pads and supporting members or other brake parts
    • F16D65/0971Resilient means interposed between pads and supporting members or other brake parts transmitting brake actuation force, e.g. elements interposed between brake piston and pad
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16DCOUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D65/00Parts or details
    • F16D65/02Braking members; Mounting thereof
    • F16D65/04Bands, shoes or pads; Pivots or supporting members therefor
    • F16D65/092Bands, shoes or pads; Pivots or supporting members therefor for axially-engaging brakes, e.g. disc brakes
    • F16D65/095Pivots or supporting members therefor
    • F16D65/097Resilient means interposed between pads and supporting members or other brake parts
    • F16D65/0973Resilient means interposed between pads and supporting members or other brake parts not subjected to brake forces
    • F16D65/0979Resilient means interposed between pads and supporting members or other brake parts not subjected to brake forces acting on the rear side of the pad or an element affixed thereto, e.g. spring clips securing the pad to the brake piston or caliper
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16DCOUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D65/00Parts or details
    • F16D65/78Features relating to cooling
    • F16D2065/785Heat insulation or reflection

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Braking Arrangements (AREA)

Abstract

A shim includes a shim pad 4 of heat resistant composite material and a metal clip 3 which overlies the shim pad, locates it in position, and clips into a brake piston 9 in a calliper. The metal clips 3 preferably protects the shim pad 4 from direct contact with the piston and the metal clip preferably does not bridge over the shim pad and all the pressure from the piston is transmitted through the shim pad. The heat-resistant composite material can be used as an insulating material to form a barrier to reduce conduction of heat from the brake pad into the piston in a disc brake assembly; the material may comprise glass fibres; mineral fibres; aromatic polyamide fibres; asbestos fibre material with binder etc. As shown, clip 3 has three clip members 6,7 (8) fitting inside piston 9, a retaining clip 5 around edge of clip 3 locating pad 4. In the embodiment of Figures 4-6, a recess (14) acts as locating means for shim pad and the metal clip is extended to the side edges of the brake pad back-plate. An annular shim pad to match the piston shape could be used. <IMAGE>

Description

SPECIFICATION Improvements relating to disc brake pads This invention relates to disc brake pads, and more particularly to disc brake pads using shims behind their back-plate.
In a disc brake for a vehicle such as a car braking effort is applied to the vehicle by forcing disc brake pads consisting of friction material attached to a steel backing plate, against a brake disc. The force is applied to the disc brake pads by means of a hydraulic piston in a brake caliper, and it is usual in a brake caliper for a piston to bear against the back-plate of at least one disc brake pad. In some cases a caliper contains more than one piston, in others the caliper uses only one piston and one pad is forced directly against the disc, an opposed pad being dragged onto the disc by reaction forces.
Shims of various kinds are in common use on the back of disc brake pads mainly to reduce noise by damping effects, or in some cases to vary the centre of pressure of the piston.
Several methods are in use for applying the shims to the pads. In the case of a metal shim this may be made to clip onto the back-plate of the pad, gripping the back-plate at its edges. Alternatively the shim may be adhered to the back-plate either by means of pressure-sensitive adhesive or by means of a heat curable adhesive. In a further alternative a form of shim may be moulded onto the back-plate by heat and pressure during moulding of the disc-brake pad.
Various disadvantages and problems have arisen in the use of shims mentioned above. For example, where the shim has been applied by means of pressure sensitive adhesive problems have been encountered with the shims moving out of position under the influence of radial forces on certain brake caliper designs.
The use of a heat-curable adhesive is expensive and inconvenient in disc brake pad production and it is difficult to achieve a bond which will withstand the cyclic high temperatures to which the bond is subject during service.
Metal shims have the disadvantage that in general, they are not as efficient in damping out noise as non-metallic or metal/rubber sandwich varieties.
We have now found a means of applying and using shims which obviates many of the above disadvantages.
The present invention provides a shim for a disc brake pad which comprises a shim pad of heat resistant composite material and, to locate said shim pad in postion on the back of said disc brake pad a metal clip which overlies the shim pad, locates it in position and when in use clips into the end of a brake piston in a disc brake caliper.
The metal clip is preferably so arranged that it prevents direct contact between the piston and the shim pad, thus preventing the piston which is annular, from cutting into the shim pad. Preferably also the metal clip does not bridge over the shim pad so that all the pressure from the piston is transmitted through the shim pad and the maximum damping effect is thus obtained.
The metal clip is preferably in the form of a plate which will overly the shim pad, and will bear some form of location means for the shim pad, e.g. a recessed area into which the shim pad fits, or a plurality of projections to locate the edge of the shim pad. If desired the shim pad can be adhered to the metal clip.
The piston in a disc brake pad caliper is usually annular where it bears onto the disc pad back-plate.
Thus in the present invention the metal clip can be provided with upstanding clip members, preferably three or more, which will engage the interior wall of the annular piston.
The shim pad is a composite material which, when protected by the metal clip, will stand up to the pressures applied by a brake piston over a wide range of temperatures ie from below 0 C to over 400 C.
Suitable composite materials are those which contain fibre reinforcements not melted or severely degraded under the conditions of use, bonded with polymers which are preferably thermosetting, such as rubber eg nitrile rubber or resin eg phenolic; mixtures of rubber and resin may be used.
The composite is preferably a material with a relatively low thermal conductivity which will act as a thermal barrier between the back plate of the brake pad and the brake piston. This is to reduce heat flow from the disc brake pad to the hydraulic piston and hence the brake fluid which can be a problem, particularly when using non-asbestos brake pads which often have a much higher thermal conductivitythan asbestos ones.
Composite materials which may be used include compressed asbestos fibre material, which can have a binder consisting of rubber and/or resin, resin bonded glass fibre reinforced material, and the non-asbestos equivalent of compressed asbestos fibre jointing materials, which may be for example, a sheet of rubber bonded heat resistant fibres, such as glass fibres, mineral fibres or aromatic polyamide fibres. One such material is described in published European Patent Application No 82 301151.5 (Publication No 0060664).
It is preferred that the composite material is one in which the fibres are substantially orientated in the plane of the sheet, in order to obtain good resistance to the compressive fibres exerted by the brake piston in use of the shim pad.
If desired the shim pad may be confined to the area of the back-plate on which the piston bears, especially if it is thermally insulating. This is to minimise the effect on heat dissipation from the disc-brake pad through interior overheating. It will be appreciated that in use the face of a disc brake pad is being rapidly heated by friction against the brake disc. If the back suface of the pad were covered with thermally insulating material the only surfaces left for heat dissipation would be the edges of the pad, which may be inadequate.
Thus the invention also provides in another aspect a disc brake assembly which comprises a brake caliper including at least one brake piston, a pair of disc brake pads and, interposed between the brake piston and that disc brake pad on which it is to bear when in use, a thermal conduction barrier which comprises a shim pad of a composite material which has a relatively low thermal conductivity and means to retain said shim pad in position between the disc brake pad and the brake piston.
The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which Figure 7 is a rear view of a disc brake pad with a shim in accordance with the invention, Figure 2 is a side elevation of the assembly shown in Figure 1, in which the brake piston is shown in section, Figure 3 is a detail cross-section on A-A of Figure 1 showing a portion of the shim in position, Figure 4 is a rear view of a disc brake pad with a shim which is a further embodiment of the invention, Figure 5 is a cross-sectional view of the assembly shown in Figure 4on line B-B, Figure 6 is a detail cross-section on A-A showing a portion of the shim of Figure 4 in position.
As shown in Figures 1 and 2 a disc-brake pad consists of a back-plate 1 on which is moulded a pad of friction material 2. A shim on the back-plate 1 consists of a zinc-plated steel clip 3 overlying a shim pad 4 of compressed asbestos fibre composite material. As shown in Figure 3 the steel clip 3 overlies the shim pad 4, there being a retaining clip 5 around the edge of the clip 3 which acts as a locating means for the shim pad beneath it. The clip 3 includes three upstanding clip members 6,7 and 8 which fit inside an annular brake piston 9 and engage its interior wall to hold the metal clip on the end of the piston.
In the alternative embodiment shown in Figures 4 and 5 a disc brake pad having a back-plate 10 and a pad of friction material 11 is provided with a shim comprising a steel clip 12 and a shim pad 13. In this case the clip 12 again overlies the shim pad 13 there being a recess 14 to act as a locating means for the shim pad. In this case three clip members 15, 16 and 17 serve to attach the clip 12 to a brake piston 18, and the metal clip is extended inside portions 19, 20 out beyond the shim pad to the side edges of the disc brake pad back-plate to provide location in the brake caliper assembly and prevent the possibility of rotation of the metal clip and shim pad.
In both the embodiments illustrated it will be noted that the steel clips 13 and 12 do not touch the back-plates 1 and 10 but the steel clips each form plates, overlying the shim pad, onto which the hydraulic piston can bear.
In each case the provision of location means for the shim pad means that the shim pad and clip could be reduced in size so that the shim pad was located only in the contact area of the piston. Indeed, an annular shim pad to match the shape of the piston could be used if desired.

Claims (16)

1. A disc brake assembly which comprises a brake caliper including at least one brake piston, a pair of disc brake pads and, interposed between the brake piston and that disc brake pad on which the piston is to bear when in use, a thermal conduction barrier comprising a shim pad of a composite material which has a relatively low thermal conductivity and means to retain said shim pad in position between the disc brake pad and the brake piston.
2. A disc brake assembly according to claim 1 in which the shim pad is a sheet of fibre-reinforced composite material in which the fibres are orientated substantially in the plane of the sheet.
3. A disc brake assembly according to claim 2 in which the fibres are heat resistant fibres selected from asbestos glass and mineral fibres and synthetic organic fibres.
4. A shim for a disc brake pad which comprises a shim pad of heat resistant composite material and, to locate said shim pad in position on the back of said disc brake pad when in use a metal clip which overlies the shim pad, locates it in position and clips into the end of a brake piston in a disc brake caliper.
5. A shim according to claim 4 in which the metal clip is so positioned as to protect the shim pad from direct contact with a brake piston when in use.
6. A shim according to claim 4 or 5 in which the metal clip is provided with a retaining lip at the edges of the shim pad to serve as the means of location of the shim pad.
7. A shim according to claim 4,5 or 6 in which the metal clip comprises a metal plate having a plurality of upstanding clip members to engage the interior surface of an annular brake piston.
8. A shim according to any preceding claim in which the shim pad is a thermally insulating material.
9. A shim according to any preceding claim in which the shim pad is dimensioned such as to occupy substantially only the area of a disc brake pad back-plate which is to be contacted by a brake piston in service, in order to avoid overheating of said disc brake pad in service.
10. A shim according to any preceding claim in which the shim pad is made from a fibre-reinforced composite material in which the fibres are orientated substantially in the plane of the sheet.
11. A shim according to claim 10 in which the fibres are heat resistant fibres selected from asbestos, glass and mineral fibres and synthetic organic fibres.
12. A shim according to claim 10 in which the composite material includes a binder which comprises a thermoset rubber and/or thermoset resin.
13. A shim according to any preceding claim in which the shim pad is made from a polymer-bonded compressed asbestos fibre material.
14. A shim according to any one of the claims 1 to 12 in which the shim pad is made from a resin bonded glass fibre reinforced material.
15. A shim substantially as described herein with reference to any one of the accompanying drawings.
16. A disc brake pad and shim assembly comprising a shim as claimed in any one of the preceding claims.
GB08329104A 1982-11-03 1983-11-01 Shims for disc brake pads Expired GB2129511B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08329104A GB2129511B (en) 1982-11-03 1983-11-01 Shims for disc brake pads

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8231416 1982-11-03
GB08329104A GB2129511B (en) 1982-11-03 1983-11-01 Shims for disc brake pads

Publications (3)

Publication Number Publication Date
GB8329104D0 GB8329104D0 (en) 1983-12-07
GB2129511A true GB2129511A (en) 1984-05-16
GB2129511B GB2129511B (en) 1986-07-30

Family

ID=26284298

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08329104A Expired GB2129511B (en) 1982-11-03 1983-11-01 Shims for disc brake pads

Country Status (1)

Country Link
GB (1) GB2129511B (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2165902A (en) * 1984-10-18 1986-04-23 Dayton Walther Corp Caliper-type disc brake
EP0218074A1 (en) * 1985-09-11 1987-04-15 ALFRED TEVES GmbH Brake pad retention spring, in particular for spot-type disc brakes for automotive vehicles
EP0322530A1 (en) * 1987-12-19 1989-07-05 Dr.Ing.h.c. F. Porsche Aktiengesellschaft Brake device
US5704452A (en) * 1995-04-25 1998-01-06 Robert Bosch Technology Corporation Brake piston and pad with automatic coupling together
EP1591688A1 (en) * 2004-04-29 2005-11-02 ROBERT BOSCH GmbH Device to be placed between a piston and a brake pad of a disc brake, and disc brake comprising said device
GB2419927A (en) * 2004-10-12 2006-05-10 Miba Frictec Gmbh Brake shoe for a disc brake
EP2350489A4 (en) * 2008-11-28 2012-05-09 Ray Arbesman Piston-side brake shim
US20120111677A1 (en) * 2010-11-04 2012-05-10 Kematis Projects Limited Heat-insulating component for brake assembly
US8776956B2 (en) 2011-01-14 2014-07-15 Cwd, Llc Brake pistons and piston noses
US8869955B2 (en) 2007-04-25 2014-10-28 Trelleborg Sealing Solutions Kalmar Ab Anti-squeal shim
WO2018104159A1 (en) * 2016-12-06 2018-06-14 Continental Teves Ag & Co. Ohg Sound damping element, motor vehicle disc brake pad with sound damping element, and use of same in a motor vehicle disc brake

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2171926C2 (en) * 1999-04-20 2001-08-10 Открытое акционерное общество Научно-исследовательский и конструкторско-технологический институт асбестовых технических изделий - Фирма ТИИР Scream-suppressing material

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1031946A (en) * 1963-08-29 1966-06-02 Heinz Teves Improvements in and relating to disc brakes
GB1192450A (en) * 1966-08-23 1970-05-20 Jurid Werke Gmbh Spot Disc Brakes with Sintered Pads
GB1278746A (en) * 1969-05-08 1972-06-21 Toyota Motor Sales Co Ltd Disc brake
GB1414915A (en) * 1972-02-07 1975-11-19 Ferodo Sa Brake assembly and friction pad
GB1515484A (en) * 1976-03-16 1978-06-28 Dba Sa Disc brake and heat shield therefor
GB2021219A (en) * 1978-05-23 1979-11-28 Sumitomo Electric Industries Disc brakes
GB1572822A (en) * 1976-03-26 1980-08-06 Girling Ltd Friction pad assemblies for disc brakes for vehicles
GB2042108A (en) * 1979-02-26 1980-09-17 Lucas Industries Ltd Vehicle disc brake
GB2089914A (en) * 1980-12-22 1982-06-30 Brembo Spa Disc brake; piston
GB2116668A (en) * 1982-03-12 1983-09-28 Valeo Thermally insulating hydraulic brake piston

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1031946A (en) * 1963-08-29 1966-06-02 Heinz Teves Improvements in and relating to disc brakes
GB1192450A (en) * 1966-08-23 1970-05-20 Jurid Werke Gmbh Spot Disc Brakes with Sintered Pads
GB1278746A (en) * 1969-05-08 1972-06-21 Toyota Motor Sales Co Ltd Disc brake
GB1414915A (en) * 1972-02-07 1975-11-19 Ferodo Sa Brake assembly and friction pad
GB1515484A (en) * 1976-03-16 1978-06-28 Dba Sa Disc brake and heat shield therefor
GB1572822A (en) * 1976-03-26 1980-08-06 Girling Ltd Friction pad assemblies for disc brakes for vehicles
GB2021219A (en) * 1978-05-23 1979-11-28 Sumitomo Electric Industries Disc brakes
GB2042108A (en) * 1979-02-26 1980-09-17 Lucas Industries Ltd Vehicle disc brake
GB2089914A (en) * 1980-12-22 1982-06-30 Brembo Spa Disc brake; piston
GB2116668A (en) * 1982-03-12 1983-09-28 Valeo Thermally insulating hydraulic brake piston

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2165902A (en) * 1984-10-18 1986-04-23 Dayton Walther Corp Caliper-type disc brake
EP0218074A1 (en) * 1985-09-11 1987-04-15 ALFRED TEVES GmbH Brake pad retention spring, in particular for spot-type disc brakes for automotive vehicles
EP0322530A1 (en) * 1987-12-19 1989-07-05 Dr.Ing.h.c. F. Porsche Aktiengesellschaft Brake device
US5704452A (en) * 1995-04-25 1998-01-06 Robert Bosch Technology Corporation Brake piston and pad with automatic coupling together
EP1591688A1 (en) * 2004-04-29 2005-11-02 ROBERT BOSCH GmbH Device to be placed between a piston and a brake pad of a disc brake, and disc brake comprising said device
FR2869658A1 (en) * 2004-04-29 2005-11-04 Bosch Gmbh Robert ELEMENT INTENDED TO BE INTERACTED BETWEEN A DISC BRAKE PISTON AND A BRAKE SKATING BRAKE AND DISC BRAKE COMPRISING A CALIPER HAVING SUCH A COMPONENT
GB2419927A (en) * 2004-10-12 2006-05-10 Miba Frictec Gmbh Brake shoe for a disc brake
US8869955B2 (en) 2007-04-25 2014-10-28 Trelleborg Sealing Solutions Kalmar Ab Anti-squeal shim
US9644695B2 (en) 2007-04-25 2017-05-09 Trelleborg Sealing Solutions Kalmar Ab Anti-squeal shim
EP2350489A4 (en) * 2008-11-28 2012-05-09 Ray Arbesman Piston-side brake shim
US8348025B2 (en) 2008-11-28 2013-01-08 Ray Arbesman Piston-side brake shim
US20120111677A1 (en) * 2010-11-04 2012-05-10 Kematis Projects Limited Heat-insulating component for brake assembly
US8776956B2 (en) 2011-01-14 2014-07-15 Cwd, Llc Brake pistons and piston noses
US10174840B2 (en) 2011-01-14 2019-01-08 Cwd, Llc Brake pistons and piston noses
WO2018104159A1 (en) * 2016-12-06 2018-06-14 Continental Teves Ag & Co. Ohg Sound damping element, motor vehicle disc brake pad with sound damping element, and use of same in a motor vehicle disc brake

Also Published As

Publication number Publication date
GB2129511B (en) 1986-07-30
GB8329104D0 (en) 1983-12-07

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PCNP Patent ceased through non-payment of renewal fee