WO2004088160A1

WO2004088160A1 - A wheel with a brake rotor

Info

Publication number: WO2004088160A1
Application number: PCT/BR2004/000044
Authority: WO
Inventors: Flávio RODRIGUES; João Alfredo GRITTI; Evandro Luís FRANCISCHETTI; Egídio Miguel GOMES CORREIA; Sérgio Charles TUBERO; Nelson Gosser, Jr.; Rafael Silva, Jr.; Paulo Roberto Becker; José Henrique BONALDI; Steven Allan Yollick
Original assignee: Arvinmeritor Do Brasil Sistemas Automotivos Ltda.
Priority date: 2003-04-03
Filing date: 2004-03-31
Publication date: 2004-10-14
Also published as: BR0300864A

Abstract

One describes a wheel (10), particularly for use on vehicles, comprising a substantially circular or truncated-cone-shaped rim (2) and a circular portion (3, 30) that is substantially associable to the rim (2), the circular portion comprising at least one turning brake element (5, 50) arranged concentrically. One also describes a circular portion (3, 30) developed for use on the present wheel (1, 10).

Description

A WHEEL WITH A BRAKE ROTOR

The present invention relates to a wheel, particularly for use on automotive vehicles, comprising a turning element of the brake system in its construction. The present invention further relates to a circular portion pro- vided with a turning element of the brake system in its construction. Description of the Prior Art

The brakes of automotive vehicles, such as automobiles, lightweight commercial and utility vehicles, work thanks to the force of friction between a non-rotary element on the vehicle, such as a friction pads and brake linings, and the wheel to be braked, that is associated to the wheel hub of the vehicle having a turning element of the brake system, usually in the form of a disc or a drum. The actuation of the brakes of the vehicle is effected, as a rule, by means of mechanical, hydraulic or pneumatic systems, or a combination thereof. Especially as far as brakes of light-weight automotive vehicles are concerned, such as light-weight automobiles and commercial vehicles, one thinks of a disc brake or hydraulic-actuation drum brake, whereas for heavy vehicles one still uses, for the most part, a combination of drum brakes actuated by compressed air. The hydraulic-actuation system is based on the fact that the liquids are uncompressible, that is to say, a pressure at any point of a liquid is automatically transmitted through the latter, and therefore the pressure exerted onto the brake pedal moves the vehicle-braking pistons located on the wheel. Speaking in greater detail, a piston associated to the brake pedal (lo- cated at a piece called master cylinder) pushes the brake fluid (also known as brake oil) through flexible brake hoses as far as the wheel cylinder, actuating pistons existing there, which pushes the shoes or pads against their respective cooperating means (drum/disc) to brake the vehicle.

Drum brakes comprise a drum, usually made of iron/steel or cast aluminum, the side wall of which defines an internal circular friction track containing a pair of semicircular brake shoes that are selectively movable to said friction track. As mentioned, the drum is fixed to the wheel hub and the wheel is fixed to it, so that both turn in conjunction with each other.

On the other hand, disc brakes consist of a disc usually made of cast steel, associated to the wheel hub, and a brake caliper provided with at least one cylinder and one driving piston, which moves at least two friction pads relative to the disc. When the brake pedal is pressed, the pistons of the wheel cylinder are displaced and cause the friction pads to meet and cause friction with the two side faces of the disc, this friction reducing the rotation speed of the wheel and, consequently, the displacement speed of the vehicle as a whole. In order to replace the friction pads and the brake lining, one should remove the wheel; (i) in the case of drum brakes, remove the drum and (ii) in the case of disc bakes, remove the caliper, and in both cases only after removing the friction element, configuring two different steps for both removal and future assembly. In the specific case of disc brakes, when it is necessary to replace the disc, there is still the step of removing the disc, configuring an additional compulsory step. These various disassembling/assembling steps may cause damages/wear for the brake-actuation assembly, mainly if the person who caries out the task does not have sufficient knowledge of mechanics. Then, the lesser the number of steps required for disassembling and assembling for the purpose of maintenance, the better. The above-mentioned damages result mainly from loss of fluid and entry of air in the hydraulic system, due to the disconnection of the brake flexible brake hoses for replacement of the worn-out element, causing malfunction of the brakes. The hydraulic system need to be hermetically sealed, because the entry of air causes loss of pressure, since air has high compressibility. In addition, the brake fluid absorbs the humidity existing in the air that has got into the system, this humidity causing internal corrosion of the communication tubes and malfunction of the system. This special reason causes difficulty and riskiness in modifying and/or making the maintenance of any element of the brake system, since one should avoid, as far as possible, the entry of air and prevent leak in the hydraulic circuit.

A vehicle wheel that could provide a reduction in the steps necessary to carry out the maintenance and replacement of brake components on an automotive vehicle, contributing to the safety and efficiency of the sys- tern, had not been developed yet. Objectives of the Invention

It is an objective of the present invention to provide a wheel, particularly for use on an automotive vehicle, which brings about reduction of the steps necessary to maintain the brake system and scale economy, so that it can be used on a large number of different vehicles.

Another objective of the present invention is to provide a circular portion for use on the aimed-at wheel. Brief Description of the Invention

The objectives of the present invention are achieved by means of a wheel, particularly for use on vehicles, comprising a substantially circular rim in the form of a truncated cone and a substantially circular portion concentrically associable to the rim, provided with at least one turning brake element, concentrically arranged.

Also, the objectives of the present invention are achieved by means of a circular portion, particularly for use on a vehicle wheel, provided with at least one turning brake element that is concentrically arranged.

The present invention has the following advantages, among others:

- joint removal of the wheel and the turning brake element (disc or drum), thus rendering the maintenance of the system easy;

- It enables one to use a single circular portion for equipping a number of vehicles, thus bringing scale economy, which ends up reducing the cost of the wheel on the consumer market; and

- It enables one to interchange components, guaranteeing great penetration of the wheel into the market.

Brief Description of the Drawings

The present invention will now be described in greater detail with reference to two embodiments represented in the drawings. The figures show.

- Figure 1 is a cross-sectional side view of a first preferred embodiment of the wheel according to the present invention; - Figure 2 is a perspective view of the first preferred embodiment of the wheel according to the present invention;

- Figure 3 is a perspective cross-sectional view of the first embodiment of the wheel according to the present invention;

- Figure 4 is a cross-sectional side view of a second preferred embodiment of the wheel according to the present invention;

- Figure 5 is a perspective view of the second preferred embodiment of the wheel according to the present invention; and

- Figure 6 is a perspective cross-sectional view of the second embodiment of the wheel according to the present invention. Detailed Description of the Figures

According to a first preferred embodiment and as can be seen in Figures 1 to 3, the wheel 1 of the present invention comprises a first turning brake element 5 (in the preferred form of a disc), and is associated to a first brake-actuation system 70. A second preferred embodiment 10 of the wheel developed now, which can be seen in Figures 4 to 6, has a second turning brake element in the form of a brake drum 50, and is associated to a second brake-actuation system 7.

In general, the hydraulic-brake system of a vehicle comprises a master cylinder directly connected to the brake pedal or the like, provided with a piston, hermetic hoses and a wheel cylinder on each of the vehicle wheels, where the other components of the brake system are also located. As already mentioned before, the hydraulic-actuation system is based on the fact that the liquids are uncompressible, that is, pressure at any point of a fluid is transmitted through the latter. Therefore, the piston associated to the brake pedal or the like pushes the oil through flexible brake hoses as far as the wheel cylinders, driving pistons existing there, which push the brake shoes or brake linings to their respective cooperating means (disc/drum) to brake the vehicle.

The wheel 1 , 10 is assembled in the conventional way, that is to say, it has a wheel rim 2 substantially cylindrical in shape or in the form of a truncated cone, to which a tire (not shown) is attached. Since the wheel rim 2 is not the objective of the present invention, it is not described in greater detail.

Whatever its preferred embodiment, the wheel 1 , 10 of the present invention has a wheel disc in the form of a first or second circular portion 3, 30, provided with a central through bore for securing it to the vehicle axle tip 6. When the wheel 1 , 10 is mounted on the vehicle, this central through bore is perpendicularly traversed by the axle tip 6. In order to enable the wheel 1 , 10 to be locked at the axle tip 6, the latter has wheel-locking means, such as a thread 200 for screwing, which cooperates with a stop nut 201. Evidently, this locking of the wheel 1 , 10 at the axle tip 6 may be of any other kind, since it is not the object of the present invention.

The first preferred embodiment 1 of the wheel according to the present invention has a first circular portion 3, which comprises the first brake element in the form of a brake disc 5, as already mentioned. The disc 5 is provided parallel and concentric with the first circular portion 3 and is sub- stantially circular in shape, defining a first and a second opposed friction surfaces 5', 5", which cooperate with friction elements, as will be mentioned later. Optionally, the brake disc 5 has radial openings or tears 5'" for ventilation, but of course these openings may be of any other shape, even provided axially with respect to the disc 5. Preferably, the brake disc 5 is an integral part of the first circular portion 3, but one may provide a disc that can be removed and replaced (thus being removable fixable to the circular portion 3). In this case, the way of fixing the disc 5 to the portion 3 may be any one, as long as it is feasible and functional. Evidently, the diameter and the thickness of the brake disc 5 may vary according to the braking capability of the system which is desired, the material from which it is made, etc., all these variables being included in the scope of the present invention.

In addition to the brake disc 5, already provided on the wheel 1 developed now, the first brake-actuation system 70 comprises an embracing element 71 , preferably in the form of a brake caliper with a cylinder having a piston, at least two friction elements 72, preferably in the form of friction pads, and a flexible brake hose 73 (generically shown).

The caliper 71 is fixed with respect to the vehicle-axle tip 6 and has a cavity somewhat larger than the thickness of the disc 5, both elements being positioned in such a way that the disc 5 will turn inside this cavity. The cavity encloses the first and second friction surfaces 5', 5". The friction pads 72 are also located inside the cavity, being opposite each other and parallel to the disc, enclosing it.

The brake actuation is effected by means of a pedal (or any other means, evidently), which moves the piston of the master cylinder, which in turn exerts pressure upon the brake fluid through the flexible brake hoses 73, moving the piston located in the cylinder of the caliper 71. The movement of the wheel-cylinder piston moves the friction pads 72, causing them to rest against the surfaces 5', 5" on the disc 5 in an axial way, causing it to stop turning due to the high friction generated. The vent openings 5'", if existent, help in dispersing the heat dissipated in the braking effort, helping to maintain a correct functioning temperature of the assembly.

Evidently, the friction pads 72 wears out with time and has to be replaced routinely during the lifetime of the vehicle. When the wheel 1 of the present invention is removed, the brake disc 5 is removed together, which facilitates the repair, but the caliper remains in place, unless it is displaced. Evidently, there is a geometric project of positioning the components with the disc 5 and brake clamp 71 , so that it will be possible to remove the wheel without the need for dismounting/moving the caliper 71. This is very interesting, since it movement might cause disconnection/partial breakage of the flexible brake hose 73 and a possible entry of air/leakage into the system.

After the wheel 1 has been removed, one has free access to the caliper 71 for replacement and repair of the friction pads 72, which is carried out in a way analogous to that of the known systems.

As can be seen in Figure 4, a second preferred embodiment 10 of the wheel according to the present invention has a second circular portion 30, which comprises the second brake element in the form of a drum 50 (al- ready mentioned), provided concentric with it, and a second brake-actuation system 7. The second embodiment of the wheel 10 also has a conventional rim 2, to which a tire (not shown) is associated.

The second circular portion 30 is analogous to the first one 3 in all aspects, with the exception of the fact that the second brake element 50 in form of a drum is different from the brake disc 5 of the first preferred embodiment 1.

The drum 50 corresponds to a projection in the form of a cylindrical wall 9, which extends from the second portion 30 concentric with it. The projection 9 faces the inside of the wheel, that is to say, it faces the side of the axle tip 6 of the vehicle and corresponds to a cylindrical wall that defines an inner surface 9', against which the brake linings of the system will be subjected, generating the friction that will cause the wheel 10 to stop and, consequently, the vehicle equipped wi th it. The drum 50 has a d ameter equivalent to, or smaller than, that of the second portion 30, and it s evident that this diameter may vary (as long as it is not larger than the diameter of the second portion 30 and is functional), as well as the area of the inner surface 9' may vary too, without the resultant wheel being left out the scope of protection of this invention.

Alternatively, it is also possible to provide a wheel 10 with a drum that does not project directly from the second portion 30, but rather is fixed to it. In this case, the way of fixing the drum 50 to the portion 30 may be any one, as long as it is feasible and functional.

In addition to the brake drum 50 already provided on the wheel

10 developed now, the second brake-actuation system 7 comprises a pair of actuation elements in the form of brake shoes 8, to which friction elements in the form of brake linings 8a are associated. It should be pointed out that these elements are illustrated in a generic way in Figure 4, since they are not the object of the present invention.

Since the drum 50 is directly cooperating with the wheel 10, turning together with it, to reduce its rotation speed (and, consequently, the vehicle speed), a force is applied to the brake shoes 8, so that the brake linings 8a will be pressed against the surface 9' of the drum 50.

For this purpose, the drum 50 comprises a wheel cylinder provided with a piston 4 and a flexible brake hose 4a. The brake actuation is effected by means of a pedal in the manner already mentioned before, so that the piston of the wheel cylinder moves the brake shoes and the brake linings 8a, positioning them against the drum 50, thus braking the wheel. The brake shoes 8 return to their rest position by means of springs (not shown), as soon as the brake pedal is no longer pressed.

Due to the use, the brake linings 8a wear out and sporadically have to be replaced. When the wheel 10 of the present invention is removed, evidently the brake shoes are exposed, since the drum 50 is an integral part of the second circular portion 30, or at lest is rigidly fixed to it. In this way, one avoids a specific removal and/or montage step the drum.

As mentioned before, one may provide the disc 5 and the drum 50 removable associable to the wheel 1 , 10, for a possible change of these elements due to the natural wear of the components. In case they are integral parts of the first and second circular portions 3, 30, they will have to be replaced when the friction causes irreparable wear of the disc 5 or drum 50.

The circular portions 3, 30 may be made from any material, as long as they will be functional, without departing from the protection scope of the present invention.

Preferably, the circular portions 3, 30 of the first and second preferred embodiments or the wheels 1 , 10 according to the present invention 1 , 10 have at least two bores 31 provided with fixing means (preferably in the form of threads) for fixing the wheel rim 2, which has at least two radial pro- jections 20 provided with cooperating bores for enabling one to screw the two components.

Thus, it becomes possible to remove only the rim 2 in the case of a flat tire, for instance, without the need to remove the circular portion 3, 30, so that the brake system will remain untouched. In this way, it is also possible to change the wheel rim easily, modifying the wheel measure, as for instance, changing a rim wheel 14" into a rim 15", modifying its width or else its "offset".

As another advantage, it is known that if the rim 2 is damaged when it falls into a hole or passes over some unevenness of the ground, one can replace it without the need to change the central portion 3, 30, thus decreasing the costs. By virtue of this flexibility, the present wheel enables one to achieve a wide range of vehicles with few designs of central portion, by using different rims, thus bring a desirable scale economy.

Evidently, other types of associations between circular portions 3, 30 and rim 2 may be used, such as rivets and soldering, among others. In order to vary the appearance of the wheels, it is possible to use optionally any stylized hub cap whatever, illustrated in the figures with reference number 400. In this way, one may provide an esthetically less attractive wheel 1 , 10, but exhibiting more functionality, the hub cap being responsible for improving its esthetics. One may evidently use other brake-actuation systems, as for example a pneumatic, mechanical system, but the components of the brake itself, namely brake calipers, friction pads, brake linings and brake shoes are equivalent, whereby these possible variations in configuration will evidently be included in the protection scope of the present invention. Two preferred embodiments having being described, it should be understood that the scope of the present invention embraces other possible variations, being limited only by the contents of the accompanying claims, which include the possible equivalents.

Claims

1. A wheel, particularly for use on vehicles, comprising a substantially circular or truncated-cone-shaped rim (2) and a circular portion (3, 30) substantially concentrically associable to the rim (2), characterized in that the circular portion comprises at least one turning brake element (5, 50), concentrically arranged.

2. A wheel according to claim 1 , characterized in that the turning brake element is a brake disc (5).

3. A wheel according to claim 2, characterized in that the brake disc (5) is substantially circular and defines a first and a second friction surfaces (5', 5") opposite each other.

4. A wheel according to claim 3, characterized in that the brake disc (5) has radial openings or tears (5'") for ventilation.

5. A wheel accord ng to any one of claims 1 to 4, characterized in that the disc (5) is releasably fi xed to the circular portion,

6. A wheel accord ng to claim 1 , characterized in that the turning brake element is a brake drum (50).

7. A wheel according to claim 6, characterized in that the brake drum (5) corresponds to a projection (9) in the form of a cylindrical wall that defines an inner surface (9') and that extends concentrically from the cylindrical portion (30).

8. A wheel according to claim 6 or 7, characterized in that the drum (50) has a diameter equal to or smaller than that of the circular portion (30).

9. A wheel according to claim 1 , 6, 7 or 8, characterized in that the drum (50) is releasably fixed to the circular portion.

10. A wheel according to any one of the preceding claims, characterized in that the circular portion (3, 30) has at least two bores (31) provided with fixing means, and the wheel rim (2) has at least two radial projec- tions (20) provided with openings, the fixation between the circular portion (3, 30) and the rim (2) being effected by cooperation between the bores (31) and the projections (20).

11. A circular portion, particularly for use on a vehicle wheel, characterized by comprising at least one turning brake element (5, 50) arranged concentrically.

12. A circular portion according to claim 11 , characterized in that the turning brake element is a brake disc (5).

13. A circular portion according to claim 12, characterized in that the brake disc (5) is substantially circular and defines a first and a second friction surfaces (5', 5") opposite each other.

14. A circular portion according to claim 13, characterized in that the brake disc (5) has radial openings or tears (5'") for ventilation.

15. A circular portion according to any one of claims 11 to 14, characterized in that the disc (5) is releasably fixed to it.

16. A circular portion according to claim 11 , characterized in that the turning brake element is a brake drum (50).

17. A circular portion according to claim 16, characterized in that the brake drum (50) corresponds to a projection (9) in the form of a cylindrical wall that defines an inner surface (9') and that extends concentrically from the circular portion (30).

18. A circular portion according to claim 16 or 17, characterized in that the drum (50) has a diameter equal to or smaller than the diameter of the circular portion.

19. A circular portion according to claim 16, 17 or 18, characterized in that the drum (50) is releasably fixed to it.

20. A circular portion according to any one of claims 11 to 19, characterized in that it has at least two bores (31 ) provided with means for fixing a wheel rim (2).