Patent ID: 12253127

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

Aspects of the present disclosure will now be described more fully with reference to the accompanying drawings. The different devices and methods disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the aspects set forth herein. Like numbers in the drawings refer to like elements throughout.

The terminology used herein is for describing aspects of the disclosure only and is not intended to limit the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

FIG.1shows a vehicle100comprising a power source110, here exemplified by a combustion engine. The power source is used to drive wheels120of the vehicle. At least some of the wheels comprise braking devices to reduce vehicle speed and to maintain the vehicle in a parked position. The vehicle100is equipped with drum brakes140arranged in connection to wheel rims130.

A drum brake is a brake that uses friction caused by a set of shoes or pads that press outward against a rotating cylinder-shaped part called a brake drum. The term drum brake usually means a brake in which shoes press on the inner surface of the drum. When shoes press on the outside of the drum, it is usually called a clasp brake. Where the drum is pinched between two shoes, similar to a conventional disc brake, it is sometimes called a pinch drum brake, though such brakes are relatively rare. A related type called a band brake uses a flexible belt or “band” wrapping around the outside of a drum. The present disclosure mainly relates to the type of drum brake where shoes press radially outwards on the inner surface of the drum.

FIG.2shows a wheel rim130and a drum220of a drum brake140. Parts of the wheel hub230is also shown inFIG.2. Drum brakes140and friction brakes are known in general, and details thereof will therefore not be discussed herein.

This example drum brake140, however, comprises a brake dust trapping arrangement which is configured inside the brake drum220to collect and to hold dust generated during braking. A brake dust trap210is arranged in the interior of the brake drum220where it traps, i.e., absorbs generated dust. The dust is then held by the dust trap and can be disposed of in a safe and controlled manner by removing the dust trap210from the drum brake140. For instance, during intervals of service which require accessing the brake drum220, e.g., during change of brake liners, shoes etc., the brake dust trap210can be removed and disposed of safely and replaced with a new one.

FIG.3shows a cross-sectional view of the drum brake140with the dust trap210. There is illustrated a brake dust trap210for a drum brake140. The brake dust trap210has an annular shape arranged to be received in a groove310formed circumferentially in the drum220of the drum brake140to trap particulate matter generated by the drum brake140. The groove310is located where brake dust tends to accumulate. The dust is trapped by the brake dust trap210both as the wheel rotates, and also when the vehicle is not moving. Brake dust may be trapped in many ways, some of which will be described below. The example inFIG.3comprises pockets configured to accumulate brake dust.

The annular shape is exemplified inFIG.5. The brake dust trap210has a width w corresponding to the width of the groove310, and an external diameter D configured to fit a corresponding diameter measure of the groove310. The internal diameter d, indicated inFIG.4, is preferably on the order of the interior diameter of the brake drum220. The position of the brake dust trap210relative to the drum220can be varied along the width of the braking surface depending on the width of the brake shoe and the diameter of the brake drum220. The shape of the brake dust trap210can be varied as per the packaging dimensions of the brake shoe and brake drum sleeve. It is furthermore appreciated that the shape of the brake dust trap may need to be configured in dependence of the amount of dust generated in a service interval. The larger the amount of dust the higher the dust retaining capacity of the trap needs to be, e.g., requiring larger sized pockets or indentations620.

According to an example, the width w is on the order of 24 mm, with an external diameter D of approximately 444 mm.

Differently from, e.g., the brake dust trap disclosed in WO 82/01574, the brake dust trap210is configured inside the brake drum220and arranged to be retained in the groove310to rotate along with the drum220. This allows the dust trap210to more efficiently trap dust inside the brake drum and not just dust escaping the brake device to an exterior of the brake drum.

The brake dust trap210is configured to be removable from the drum brake140for disposal of the trapped particulate matter. Thus, when the dust trap has trapped an amount of dust, it can be removed from the brake drum220and disposed of, or it can be cleaned and re-used.

To retain the brake dust trap210in the groove310, any of a snap fit mechanism and/or an interference fit mechanism can be used. An interference fit, also known as a press fit or friction fit is a fastening between two parts which is achieved by friction after the parts are pushed together, rather than by any other means of fastening.

A snap-fit is an assembly method used to attach flexible parts to form the final product by pushing the parts' interlocking components together. There are a number of variations in snap fits, including cantilever, torsional and annular. Snap fits are an alternative to assembly using, e.g., threaded fasteners, and have the advantages of speed and cost efficiency.

To facilitate convenient mounting and removal of the dust trap, the brake dust trap can be arranged separable into a plurality of segments710,720,730,740, as illustrated inFIG.7. The segments can then be inserted into the brake drum220one after the other, which may be easier than getting the entire annular structure into the groove at one time. The segmentation may also facilitate removal from the brake drum220when the dust trap is to be replaced. The different segments may be configured with snap fit arrangements, or just pressed into the groove adjacent to each other.

According to aspects, with reference toFIG.6, the brake dust trap210comprises a plurality of protruding portions610extending radially inwards from the brake dust trap, spaced apart by indentations620or pockets. This geometrical arrangement provides for a larger area with which dust can be trapped.

To trap the dust, the brake dust trap210may comprise a porous filter material configured to absorb and to hold particulate matter. The brake dust trap210may also comprise a magnetic material configured to attract and to hold magnetic particulate matter, and/or a sticky, adhesive, or viscid surface portion configured to adhere to and to hold particulate matter. It is noted that a combination of different dust trapping mechanisms may be used in combination or separately.

In general, the brake dust trap210may be formed from any porous filter material which is able to filter and collect the dust generated during braking, and which is also able to withstand high temperatures in the range of +150 degrees Celsius and above.

The brake dust trap210may further comprise a protrusion or other geometrical configuration which is matched to a corresponding geometrical configuration in the groove,310. For instance, the brake dust trap210may comprise one or more recesses810, shown inFIG.8, extending radially inwards from the brake dust trap210perimeter510to match and to mate with corresponding protrusions820formed in the groove310. This way it becomes more difficult to use a generic dust trap with a specific brake drum220, since the recess810formed in the brake dust trap210needs to be matched geometrically to the ‘key’ protrusion shape820in the groove310. In other words, the nature of fitment of the trap into the brake drum220can be made unique to secure aftermarket business, which is an advantage. Also, the protrusions820can be configured in dependence of the dust trap dimensions. This way, it becomes impossible or at least difficult to fit a dust trap having the wrong dimensions into a given brake drum groove310.

There is also disclosed herein a drum brake140with a brake drum220comprising a groove310formed circumferentially in the drum220of the drum brake140. The groove310is arranged to receive and to retain the brake dust trap210discussed above.

According to aspects, the groove310is formed in the drum220on a hub230side of a brake shoe of the drum brake. This means that the dust trap210is located to the side of the wheel hub, where most dust tends to gather. The preferred location of the dust trap relative to the brake drum220is best seen inFIG.3, where it is shown adjacent to the wheel hub230. The position of the groove310enclosing the brake dust trap is preferably chosen keeping in mind the area where the brake dust predominantly accumulates due to brake drum rotation.

With reference toFIG.8, according to aspects, the groove310comprises at least one protrusion820arranged to mate with a corresponding recess810configured to extend radially inwards from the brake dust filter210perimeter.

Due to the protrusions820in the groove310, a dust trap210needs to comprise a set of recesses810matching the protrusions820in order for it to be fitted. A generic dust trap210will not fit into a groove310with the protrusions820. This way it can be ensured that generic dust traps are not used. Also, brake drums can be fitted with protrusions820in dependence of, e.g., dimension or brake type. This makes it more difficult to fit an unsuitable dust trap into a brake drum.

Also, as noted above, the drum brake140may be arranged to retain the brake dust trap210by any of an interference fit mechanism and/or a snap fit mechanism.