GB2277968A - Improvements in and relating to disc brake pads - Google Patents
Improvements in and relating to disc brake pads Download PDFInfo
- Publication number
- GB2277968A GB2277968A GB9309945A GB9309945A GB2277968A GB 2277968 A GB2277968 A GB 2277968A GB 9309945 A GB9309945 A GB 9309945A GB 9309945 A GB9309945 A GB 9309945A GB 2277968 A GB2277968 A GB 2277968A
- Authority
- GB
- United Kingdom
- Prior art keywords
- pad
- edge
- disc brake
- friction material
- material component
- 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
Links
- 239000002783 friction material Substances 0.000 claims abstract description 15
- 239000010425 asbestos Substances 0.000 claims abstract description 9
- 229910052895 riebeckite Inorganic materials 0.000 claims abstract description 9
- 239000000203 mixture Substances 0.000 description 7
- 239000004615 ingredient Substances 0.000 description 5
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000009472 formulation Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 206010001488 Aggression Diseases 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000005864 Sulphur Substances 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 239000003082 abrasive agent Substances 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 229910000410 antimony oxide Inorganic materials 0.000 description 1
- 239000004760 aramid Substances 0.000 description 1
- 229920003235 aromatic polyamide Polymers 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000003607 modifier Substances 0.000 description 1
- VTRUBDSFZJNXHI-UHFFFAOYSA-N oxoantimony Chemical compound [Sb]=O VTRUBDSFZJNXHI-UHFFFAOYSA-N 0.000 description 1
- 239000002006 petroleum coke Substances 0.000 description 1
- 238000009747 press moulding Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- YPMOSINXXHVZIL-UHFFFAOYSA-N sulfanylideneantimony Chemical compound [Sb]=S YPMOSINXXHVZIL-UHFFFAOYSA-N 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
- GFQYVLUOOAAOGM-UHFFFAOYSA-N zirconium(iv) silicate Chemical compound [Zr+4].[O-][Si]([O-])([O-])[O-] GFQYVLUOOAAOGM-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D69/00—Friction linings; Attachment thereof; Selection of coacting friction substances or surfaces
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D65/00—Parts or details
- F16D65/02—Braking members; Mounting thereof
- F16D65/04—Bands, shoes or pads; Pivots or supporting members therefor
- F16D65/092—Bands, shoes or pads; Pivots or supporting members therefor for axially-engaging brakes, e.g. disc brakes
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D69/00—Friction linings; Attachment thereof; Selection of coacting friction substances or surfaces
- F16D69/02—Composition of linings ; Methods of manufacturing
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D69/00—Friction linings; Attachment thereof; Selection of coacting friction substances or surfaces
- F16D2069/002—Combination of different friction materials
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Braking Arrangements (AREA)
Abstract
A non-asbestos disc brake pad having in use a radially inward edge and radially outward edge together with side edges connecting said inward and outward edges, comprises a first friction material component 2 which in use constitutes a major portion of the braking surface of the pad and second friction material component 3 which constitutes a minor portion of said braking surface, wherein said minor portion is disposed adjacent said radially outward edge and constitutes at least part of one side edge of the pad. <IMAGE>
Description
ImDrovements in and relating to disc brake pads
This invention relates to disc brake pads comprised of segments having different frictional properties.
It is known to product composite friction products in which at least two different friction materials having different abrasive characteristics are used. For example, GB-A-1143992 discloses a product for use in railway wheel braking. According to the teaching of this patent, a railway wheel brake block is provided with a region which is more abrasive, said region being disposed so as to contact the work-hardened part of the wheel tread. A less abrasive component of the block is disposed so as to contact the remainder of the tread, which is not as hard.
The objective is to produce a block which wears uniformly in use.
It is also known, for example, from GB-A-2125122 to manufacture a pad in which side-by-side segments are used to achieve better performance in both wet and dry conditions.
GB-A-2219365 highlights a different problem which is specific to disc brake pads. This problem is that it is very common for the disc itself to be very slightly mis-aligned with respect to its axis of rotation, so that even when the disc brake pads are not being applied to effect braking, there is still some intermittent contact between the pad and the disc. As a result, the disc is progressively worn unevenly by the intermittent contact, so that it no longer has a uniform thickness. This kind of asymmetric wear eventually results in brake judder. This phenomenon may manifest itself not only as vibration which is felt through the brake pedal, but it may also affect the steering/handling of the vehicle, due to the vibration which develops.
G-A-2219365 addresses this problem by providing a disc brake pad with a central primary braking portion of relatively greater abrasive characteristic and at least one side edge portion of a somewhat less abrasive material. A typical pad of the kind disclosed in the aforesaid specification has three components, side-by-side with respect to the direction of rotation of the associated brake disc. The boundaries between the side-by-side portions are disposed generally radially with respect to the axis of rotation, when the pad is in use in a brake calliper.
It has now been discovered that a modified construction has advantages and it is an object of the present invention to provide an improved disc brake pad of the kind disclosed in GB-A
According to the present invention, a non-asbestos disc brake pad having in use a radially inward edge and a radially outward edge together with a pair of side edges connecting said inward and outward edges, comprises a first friction material component which in use constitutes a major portion of the braking surface of the pad and a second friction material component which in use constitutes a minor proportion of said braking surface, wherein said minor proportion is disposed predominantly adjacent said radially outward edge and constitutes at least part of one side edge region of the pad. Preferably said second friction material component is constituted by two minor portions disposed at opposite side edges of said pad. The minor portion or portions may extend from the radially inward edge of the pad, but preferably the radially inward edge region is composed entirely of the first friction material component, the minor portion or portions being confined to the vicinity of the radially outward edge so as to be predominantly contained by the corner of the pad defined between said radially outward edge and a side edge of the pad.
The first friction material component should have normal frictional characteristics. The second component should be selected so as to exhibit less aggressive behaviour towards the material of the disc. Typical brake pad compositions may include organic and/or inorganic fibres, fillers and friction modifiers, together with at least one polymeric binder material, the desired difference in coefficient of friction being achieved by appropriate selection of the ingredients, in the usual way. The polymeric binder may be a thermosetting resin or a rubber, or a mixture of both of these.
By selectively locating the minor portion or portions so that they are predominantly radially outwardly with respect to the inner edge of the pad, it is possible to increase the major braking surface area of the pad, without significant penalty as regards disc wear in the non-braking condition, for example, where the disc has a degree of mis-alignment which causes it to contact the pad in a cyclic, non-uniform manner when the brake is not applied.
The pads of this invention are preferably made by cold moulding a mixture of ingredients to form a coherent preform which is thereafter heated in an oven to cure the binder system. The two components are loaded into a mould using, for example, a simple template to ensure that they do not mix until loading is complete and the template is removed. Subsequent press moulding followed by curing serves to unite the portions, to yield an essentially integral disc brake pad. It will be appreciated that such pads are normally moulded directly onto a conventional metal backing plate, to which an adhesive composition has previously been applied.
In order that the invention be better understood, several embodiments of it will now be described by way of Example which reference to the accompanying drawings which are all plan views of disc brake pads according to the invention, together with conventional backing plates. In the interests of clarity, like reference numerals will be applied to like parts in each Figure.
Thus, in Figure 1 a back-plate 1 is provided with a non-asbestos disc brake pad comprising a central major braking portion 2, on either side of which there is a minor portion 3.
In Figures 2-4, further embodiments of the invention are illustrated, like parts bearing like reference numerals to those in Figure 1, as mentioned earlier.
Typical formulations for these components are as follows:
Ingredient % bv vol % bv vol
(major portion) (minor portion)
NBR rubber 12.0 12.0
Copper fibre 3.5 3.5
Aramid fibre 6.5 6.5
Zirconium silicate 5.0
Aluminium oxide 3.0
Antimony oxide 2.5 2.5
Antimony sulphide 2.0 2.0 Nolybdenum disulphide 2.0 2.0
Graphite 16.0 16.0
Petroleum coke 13.5 13.5
Barium sulphate 27.5 35.5
Zinc powder 1.0 1.0
Tin powder 1.0 1.0
Calcium hydroxide 2.0 2.0
Sulphur 2.0 2.0
It will be appreciated that the essential difference between the two formulations just described resides primarily in the abrasive content. All the pads were made by the cold moulding process described earlier, using a template to locate the respective friction material ingredients during the filling of the mould.
After filling, the templates were removed, to allow the ingredients to mix at the interfaces between the respective portions so that an essentially integral product resulted. All were moulded directly onto their respective back plates 1.
In tests carried out with the pad construction of Figure 2 it was observed that reduced disc wear during off brake running periods (ie at ambient temperature and very low running pressures) was obtained, as a result of the decrease in the area of the more abrasive major portion 2 at and in the vicinity of the radially outward edge of the pad. This was accomplished even though the disc was slightly mis-aligned and periodically contacted the minor portion 3 (depending on the direction of rotation of the disc). In fact, it appears that because the mis-alignment is most noticeable at the radially outward edge of the brake disc, it is only necessary to provide relatively less abrasive portions in this region.
Claims (6)
1. A non-asbestos disc brake pad having in use a radially
inward edge and radially outward edge together with side
edges connecting said inward and outward edges, comprising
a first friction material component which in use
constitutes a major portion of the braking surface of the
pad and second friction material component which
constitutes a minor portion of said braking surface,
wherein said minor portion is disposed predominantly
adjacent said radially outward edge and constitutes at
least part of one side edge of the pad.
2. A non-asbestos disc brake pad according to claim 1 wherein
said second friction material component is constituted by
two minor portions disposed at opposite side edges of said
pad.
3. A non-asbestos disc brake pad according to claim 1 or claim
2 wherein the minor portion extends from the radially
inward edge of the pad to the radially outward edge
thereof.
4. A non-asbestos disc brake pad according to claim 1 or claim
2 wherein the radially inward edge region of the pad is
composed substantially entirely of the first friction
material component and the minor portion is confined to the
vicinity of the radially outward edge so as to be
predominantly contained by the corner of the pad defined
between said radially outward edge and a side edge thereof.
5. A non-asbestos disc brake pad according to any of claims 1
to 4 wherein the first friction material component is
formulated to be more abrasive than the second friction
material component.
6. A non-asbestos disc brake pad substantially as described
with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9309945A GB2277968B (en) | 1993-05-14 | 1993-05-14 | Improvements in and relating to disc brake pads |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9309945A GB2277968B (en) | 1993-05-14 | 1993-05-14 | Improvements in and relating to disc brake pads |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9309945D0 GB9309945D0 (en) | 1993-06-30 |
| GB2277968A true GB2277968A (en) | 1994-11-16 |
| GB2277968B GB2277968B (en) | 1997-04-02 |
Family
ID=10735472
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9309945A Expired - Fee Related GB2277968B (en) | 1993-05-14 | 1993-05-14 | Improvements in and relating to disc brake pads |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2277968B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998031949A1 (en) * | 1997-01-18 | 1998-07-23 | Lucas Industries Public Limited Company | Friction pad for a disc brake assembly |
| US8151433B2 (en) | 2007-08-01 | 2012-04-10 | Federal-Mogul Products, Inc. | Method of making disc brake pads |
| US8505698B2 (en) | 2007-08-01 | 2013-08-13 | Federal-Mogul Products, Inc. | Brake pad |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1143992A (en) * | 1966-08-04 | 1969-02-26 | Ferodo Ltd | Railway brake block |
| WO1984001412A1 (en) * | 1982-09-30 | 1984-04-12 | Ford Motor Co | A brake pad for reducing brake noise |
| GB2216066A (en) * | 1988-02-23 | 1989-10-04 | Honda Motor Co Ltd | Method of manufacturing a pad for a disk brake |
| GB2219365A (en) * | 1988-06-02 | 1989-12-06 | Honda Motor Co Ltd | Friction pad for use with disc brake |
-
1993
- 1993-05-14 GB GB9309945A patent/GB2277968B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1143992A (en) * | 1966-08-04 | 1969-02-26 | Ferodo Ltd | Railway brake block |
| WO1984001412A1 (en) * | 1982-09-30 | 1984-04-12 | Ford Motor Co | A brake pad for reducing brake noise |
| GB2216066A (en) * | 1988-02-23 | 1989-10-04 | Honda Motor Co Ltd | Method of manufacturing a pad for a disk brake |
| GB2219365A (en) * | 1988-06-02 | 1989-12-06 | Honda Motor Co Ltd | Friction pad for use with disc brake |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998031949A1 (en) * | 1997-01-18 | 1998-07-23 | Lucas Industries Public Limited Company | Friction pad for a disc brake assembly |
| US8151433B2 (en) | 2007-08-01 | 2012-04-10 | Federal-Mogul Products, Inc. | Method of making disc brake pads |
| US8505698B2 (en) | 2007-08-01 | 2013-08-13 | Federal-Mogul Products, Inc. | Brake pad |
| US8689421B2 (en) | 2007-08-01 | 2014-04-08 | Federal-Mogul Products, Inc. | Method of making disc brake pads |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9309945D0 (en) | 1993-06-30 |
| GB2277968B (en) | 1997-04-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20020514 |