GB2598790A

GB2598790A - Brake actuator gasket

Info

Publication number: GB2598790A
Application number: GB2014491.1A
Authority: GB
Inventors: William Bentley Alexander
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2020-09-15
Filing date: 2020-09-15
Publication date: 2022-03-16
Also published as: GB202014491D0

Abstract

A brake actuator gasket 22 comprises a body 30 having a first face 32 configured to seal against a mating surface (25, fig 2) of a brake actuator (24) and a second face 34 configured to seal against a bulkhead (20). A first aperture 36 allows passage of a brake pedal linkage (12) and second apertures 38A, 38B enable passage of fixings (16) therethrough. The first face and/or second face comprises an irregular surface, such as ribs 42, 44, for damping noise and/or vibration and compression limiters 40A, 40B are provided at the second apertures to resist torque relaxation of the fixings. The gasket 22 may have a first rib 42 defining a first loop shape that encloses the first aperture 36 and a second rib 44 defining a second loop shape that encloses an area larger the first aperture 36. The compression limiters 40A, 40B may be recessed metallic discs. Reference is also made to a vehicle brake actuator system comprising the brake actuator gasket 22 and to a vehicle having the brake actuator system.

Description

BRAKE ACTUATOR GASKET

TECHNICAL FIELD

The present disclosure relates to a brake actuator gasket. In particular, but not exclusively, the brake actuator can be manually and electrically actuated.

BACKGROUND

Brake actuators are known. A brake actuator may be attached to a bulkhead separating a vehicle cabin from a vehicle engine bay of the vehicle. It is known for a brake actuator to be provided with a thin strip of environmental sealing material, for preventing water ingress into the vehicle cabin. An example sealing material is 1mm thick foam that compresses to a negligible thickness when the brake actuator is firmly attached to the bulkhead. The material is ineffective at damping vibrations.

Different types of brake actuators generate different amounts of noise and/or vibration. Electrohydraulic brake actuators with an electrical actuator can generate some actuator noise.

The present invention seeks to address the problems associated with previous gasket designs.

SUMMARY OF THE INVENTION

Aspects of the invention are defined in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: FIG. 1 illustrates an example of a vehicle; FIG. 2 illustrates an example of a system; FIG. 3 illustrates an example of a brake actuator gasket; and FIG. 4 illustrates an example of a section through a brake actuator gasket.

DETAILED DESCRIPTION

FIG. 1 illustrates an example vehicle 1 within which embodiments of the invention can be implemented.

FIG. 2 illustrates a vehicle brake actuator system 2 for controlling friction brakes 28. The system 2 comprises a brake actuator 24. The brake actuator 24 comprises an electric machine 26. The brake actuator 24 is configured to apply friction braking in dependence on actuation by the electric machine 26. The brake actuator 24 may be an electro-hydraulic brake actuator.

The brake actuator 24 may comprise a brake booster.

The brake actuator 24 is fixed to a bulkhead 20 of the vehicle 1 via fixings 16 such as bolts and bolt fasteners 18 (e.g. nuts).

The system 2 may comprise a mechanical brake pedal linkage 12 connected at one end to a brake pedal 10 (e.g. foot pedal) and at the other end to the brake actuator 24. The brake pedal linkage 12 may extend through an aperture in the bulkhead 20. The brake pedal linkage 12 may comprise a rod or similar.

The brake pedal linkage 12 may be surrounded by a gaiter 14 along at least part of its length, for maintaining a dust-proof seal between the brake pedal linkage 12 and the brake actuator 24 while accommodating relative movement between the brake pedal linkage 12 and the brake actuator 24. The brake pedal linkage 12 allows the brake actuator 24 to be manually actuated.

The system 2 comprises a brake actuator gasket 22 between the brake actuator 24 and the bulkhead 20, for damping noise and/or vibration into the cabin.

FIGS. 3-4 show an example of the brake actuator gasket 22 comprising: -a body 30 having a first face 32 configured to seal against the mating surface 25 of the brake actuator 24 and a second face 34 configured to seal against a bulkhead 20; - a first aperture 36 configured to enable passage of the brake pedal linkage 12 therethrough; and - second apertures 38A, 38B configured to enable passage of the fixings 16 therethrough, - wherein at least one of the first face 32 and the second face 34 comprises an irregular surface for damping noise and/or vibration, and - compression limiters 40A, 40B at the second apertures 38A, 38B to resist torque relaxation of the fixings 16.

The body 30 may be formed from ethylene propylene diene monomer (EPDM) rubber for good damping characteristics, good resistance to brake fluid and good resistance to thermal aging.

The body 30 may have a Shore A hardness of between approximately 30 and approximately 60, such as approximately 40 (ASTM D2000), for good damping characteristics but sufficient integrity when compressed by highly-torqued fixings.

The body 30 may have a total thickness greater than 2mm, such as approximately 4.5mm. This provides substantial damping.

The outer peripheral edge of the body 30 may form a rounded rectangle in shape as shown, or another shape.

The first aperture 36 may be a central aperture in a central region of the body.

The first aperture 36 may be sized to enable passage of the gaiter 14 therethrough, as well as the linkage 12.

The first aperture 36 may have a diameter of at least 50mm, such as between 65mm-75mm

in an example.

The first aperture 36 may be generally circular.

The number of second apertures may depend on the number of fixings 16 required by the brake actuator 24. In this case there are two second apertures 38A, 383, separated across a single diagonal of the gasket 22. In another example there are four second apertures, e.g. in a quadrilateral pattern.

The second apertures 38A, 383 may be peripheral relative to the first aperture 36, towards an outer peripheral edge of the body 30.

The second apertures 38A, 383 may have a smaller diameter than the first aperture 36. The second apertures 38A, 383 may have a radius of at least 5mm, such as 11 mm in an example.

One or both of the first face 32 and the second face 34 may comprise an irregular surface. In the illustrations both faces 32, 34 comprise irregular surfaces.

An irregular surface may be defined by one or more ribs. Ribs are long, narrow and protrude from the otherwise-planar gasket face. The ribs improve damping. The ribs improve the compressibility of the gasket 22 for damping, without having to choose another less-durable material for the gasket 22. A small number of ribs as shown is better than relying on a plurality of corrugations, so there is not too much material to be compressed which would reduce the compliance of the gasket 22. In an alternative example, corrugations formed by lots of ribs are provided.

The ribs may follow nonlinear paths.

As shown in FIG. 4, the rib cross-sections may reduce in width with increasing height, for example the cross-sections may be approximately triangular. This ensures there is not too much material to be compressed which would reduce the compliance of the gasket 22.

A first rib 42 may extend (continuously or discontinuously) along a path defining a loop shape that encloses a first area comprising the first aperture 36 but not the second apertures 38A, 38B. The first rib 42 is therefore an inner rib. In the illustrated example the first rib 42 is continuous and forms a closed loop ('the loop shape').

Both the first face 32 and the second face 34 may comprise a first rib 42, to improve damping.

The loop shape of the first rib 42 may correspond to a circular shape superimposed with another shape (in this case an oval), resulting in a quatrefoil shape (in this case an oval overlapped with a circle). This complex shape helps to maintain a complex lossy contact area between the gasket and the mating surface 25/bulkhead 20, for improved damping.

The circular part of the loop may have a substantially constant distance from an outer circumference of the first aperture 36, e.g. constant radius. The oval part increases in distance from the first aperture 36.

If there are two diagonally-separated second apertures 38A, 38B as shown, the loop shape of the first rib 42 may be an asymmetrical shape, comprising indents in the vicinity of the second apertures 38A, 38B to avoid clashing with the second apertures 38A, 38B.

The first rib 42 may have a first cross-sectional area at a first location where the first rib 42 is proximal to one of the second apertures 38A, 38B, and a second greater cross-sectional area at a second location where the first rib 42 is distal from the second apertures 38A, 38B. The rib thickness (protrusion from the plane of the face 32/34) and optionally width may be greater at the second location than at the first location. This variable rib area ensures continuous contact with the bulkhead 20 in regions that are not pressed tightly by fixings 16.

In the illustrated example of two second apertures 38A, 38B across a first diagonal, the first location referred to above is on the diagonal that intersects the second apertures 38A, 38B, and the second location is on the opposite diagonal that does not intersect any second apertures.

The average thickness of the first rib 42 may be less than 2mm, for example approximately 1-1.5mm.

A second rib 44 may extend (continuously or discontinuously) along a path defining a second loop shape that encloses a second area larger than the first area. The second area may comprise the first aperture 36 and the second apertures 38A, 38B. The second rib 44 is therefore an outer rib. In the illustrated example the second rib 44 is continuous and forms a closed loop ('the second loop shape').

The second apertures 38A, 38B may be located between the first rib 42 and the second rib 44.

Both the first face 32 and the second face 34 may comprise a second rib 44, to improve damping.

The second rib 44 may be positioned at a substantially constant distance from the outer peripheral edge of the face 32/34.

The first rib 42 may get closer to and further away from the second rib 44 at various locations, e.g. due to the oval part of the shape of the first rib 42.

The separation between the first rib 42 and the second rib 44 may increase in the vicinity of second apertures 38A, 38B, for example due to the indent of the first rib 42.

Like the first rib 42, the second rib 44 may have a first cross-sectional area at the first location referred to above and a second greater cross-sectional area at the second location referred to above.

The average thickness of the second rib 44 may be similar to that of the first rib 42.

The first rib 42 and the second rib 44 together form two rows of ribs per face. In an alternative embodiment more rows of ribs are provided, not more than 6 rows. In another alternative embodiment one rib is provided. The one rib may have a more serpentine shape than that of the illustrated first and second ribs 42, 44, at the expense of greater manufacturing complexity.

In some examples if one of the first rib 42 and second rib 44 is discontinuous, the other rib 44, 42 is continuous to ensure that environmental sealing is complete.

A compression limiter 40A, 40B may be provided at each of the second apertures 38A, 38B.

The compression limiters 40A, 40B are relatively rigid compared to the body 30 (e.g. EPDM) of the gasket 22. The compression limiters 40A, 40B may comprise metallic discs. The metal may comprise steel optionally with an oxidation-resistant coating.

A central aperture through the disc 40A, 40B provides the second aperture 38A or 38B.

The compression limiters 40A, 40B may be recessed within a thickness dimension of the body 30 as shown in FIG. 4. The compression limiter thickness may be less than the maximum thickness (e.g. rib-to-rib thickness) of the body. The compression limiter thickness may be the same as the face-to-face thickness of the body.

A compression limiter 40A, 40B may have a thickness of approximately half the maximum (e.g. rib-to-rib) thickness of the body 30, such as approximately 2mm.

Claims

CLAIMS1 A brake actuator gasket (22) comprising: a body (30) having a first face (32) configured to seal against a mating surface (25) of a brake actuator (24) and a second face (34) configured to seal against a bulkhead (20); a first aperture (36) configured to enable passage of a brake pedal linkage (12) therethrough; and second apertures (38A, 38B) configured to enable passage of fixings (16) therethrough, wherein: at least one of the first face and the second face comprises an irregular surface for damping noise and/or vibration; and compression limiters (40A, 40B) are provided at the second apertures to resist torque relaxation of the fixings.
2. The brake actuator gasket of claim 1, wherein the irregular surface comprises a first rib (42).
3. The brake actuator gasket of claim 2, wherein the first rib extends along a path defining a loop shape that encloses a first area comprising the first aperture but not the second apertures.
4. The brake actuator gasket of claim 2 or 3, wherein the first rib has a first cross-sectional area at a first location where the first rib is proximal to one of the second apertures, and wherein the first rib has a second greater cross-sectional area at a second location where the first rib is distal from the second apertures.
5. The brake actuator gasket of any one of claims 2 to 4, wherein the irregular surface comprises a second rib (44) extending along a path defining a second loop shape that encloses a second area larger than the first area.
6. The brake actuator gasket of any preceding claim, wherein the compression limiters are recessed within a thickness dimension of the body.
7. The brake actuator gasket of any preceding claim, wherein the compression limiters comprise metallic discs.
8. The brake actuator gasket of any preceding claim, wherein the body comprises ethylene propylene diene monomer (EPDM) rubber.
9. A vehicle brake actuator system (2) comprising the brake actuator gasket of any preceding claim and the brake actuator, wherein the brake actuator comprises an electric machine (26) that, in use, generates at least some of the noise and/or vibration.
10. A vehicle (1) comprising the vehicle brake actuator system of claim 9.