This report presents the detailed description and is accompanied by explanatory drawings of a new concept of master cylinder for automotive vehicles brake systems, preferably for small size vehicles which have a small engine compartment; this master cylinder has an innovative and different configuration, being presented in an extruded section housing, which substantially facilitates the design and the manufacturing of the master cylinder, assembled as a single master cylinder, double in line (tandem) master cylinder and/or double master cylinder with the pressure chambers arranged preferably in a parallel configuration.

Currently, all master cylinder models for automotive vehicles are manufactured using cast material housings, which need specific foundry systems and tooling. Single master cylinders have only one pressure chamber arranged longitudinally in the housing which is also manufactured preferably in a cylindrical shape. The double master cylinders used more frequently in a brake system for an automotive vehicle are manufactured with their chambers arranged one after the other, i.e. in tandem configuration, also assembled in cast material housing, preferably with a cylindrical shape. These tandem and single master cylinders are comprised of several components, which are: primary piston, bushing, bolt, primary spring, and back static seal; in addition, for a tandem master cylinder there are: the secondary piston, secondary spring, the internal seal, fittings, among others. All current master cylinders are manufactured using cast housings which have some particular internal sections

machined. Cast housings are prone to present casting porosity, which causes a series of critical defects in master cylinders.

The single master cylinder, single in line and/or double in parallel configuration with extruded housing, object of the present patent, is comprised by a housing manufactured with an extruded section material, which means several benefits when compared to master cylinders manufactured with cast housing; among them, the following benefits can be mentioned:

- Reduction of housing porosities found in the production line, reducing rejects and eliminating the line rejection up to 2% due to porosity defects. It eliminates the need for porosity testing in the master cylinder production line, as well as the high pressure tightness tests, which are normally performed on master cylinder cast housings;

- The reliability improvement on product dimensioning and product quality on the market, avoiding porosity and leaks during the product life; - The increase in the housing material strength which allows reducing the dimensional parameters and others, providing material reduction and manufacturing cost saving, without affecting the product quality and its safety technical characteristics;

- The productivity gain on the master cylinder machining time, since it does not need finishing operations and specific inlet and outlet hydraulic ports, reducing manufacturing and machining steps on its production;

- The tooling productivity gain and savings, reducing the production and tooling costs up to 97%, when compared to a master cylinder made of aluminum cast housing, and 86% for cast iron housing. This gain is

achieved due to a housing made of an extruded section already shaped for the manufacturing of the master cylinder.

Next, there are references to the illustrative drawings that accompany this descriptive report. In order to better understand and to illustrate this report:

Figure 1 shows a schematic representation of the single master cylinder (a), or a tandem master cylinder (B), currently being used, manufactured with cast material housings. It is presented in a lateral exploded view, in order to show the component quantity, and the cylinder construction shape.

Figure 2 shows a drawing of the single master cylinder, or a tandem one, manufactured with an extruded section housing showing its entire configuration details in a perspective view (a, b), side view (c) and top view (d).

Figure 3 shows a schematic representation of the double parallel master cylinder, manufactured with an extruded section housing showing all its configuration details with an perspective view (a, b), side view (C) and top view

(D).

The master cylinder for automotive vehicle's brake systems, constructed as a single master cylinder, tandem master cylinder and/or double parallel (1) with extruded section housing, object of the present patent is comprised basically by an housing (2) made of extruded section with convenient shape and cross section dimension, according to the number of chambers and components of the single and/or parallel master cylinder. Wherein the single master cylinder contains a chamber, preferably cylindrical, arranged longitudinally to the axis of the master cylinder, and/or perpendicularly to the

extruded section cross section, and this chamber has the main components, such as: a piston, a piston return spring; the piston may present a static and/or dynamic sealing, sealing ring, and inlet and outlet hydraulic ports (4), and a support rod to actuate the master cylinder. Wherein the tandem master cylinder contains two chambers, preferably cylindrical, arranged longitudinally to the axis of the master cylinder, one after another in a tandem configuration, and/or perpendicularly to the extruded section cross section, and these chambers have their main components, such as: a primary and secondary piston, a return spring for each piston, the piston may present static and/or dynamic sealing, sealing rings, and inlet and outlet hydraulic ports (4), a support rod to actuate the master cylinder. And, wherein the double master cylinder contains two parallel chambers (3), one on the left-hand side and another on the right-hand side, and the chambers have the same configuration and also the same components, such as: pistons, piston return springs, sealing rings, and inlet and outlet hydraulic ports, and piston may present also static sealing and/or dynamic sealing, sealing ring, and inlet and outlet hydraulic ports (4), for each chamber in an independent way, allowing yet the use of only one extension rod (5), which can be essentially a simple rod and/or a fork shape, or "U" shaped yoke connected to a rod, or yet any shape presenting two driven ends connected to a support rod to actuate the master cylinder.

This new concept allows the replacement of the current back static sealing concept by a dynamic sealing, which uses O-rings installed on the master cylinder drive piston itself.

The master cylinder for automotive vehicle brake systems, single master cylinder, tandem master cylinder and/or double parallel master cylinder

(1) with extruded section housing, object of the present patent, has several other benefits regarding the conventional single and double master cylinders, which have one or two chambers, primary and/or secondary. Among these benefits, it can be mentioned: The riddance of existing parts of the conventional design for current master cylinders, such as the primary piston, the bushing, the bolt and the back static sealing, for the parallel double cylinder, as well as the possibility to eliminate the sealing sphere use and the swaging operation for the sphere. The design simplification and saving on components since all chambers are equal, as well as the savings on materials and labor due to a housing made of an extruded section, globally eliminate several machining steps on the manufacturing and finishing process for the master cylinder.

This new master cylinder design changes the current concept of single and double master cylinders, to a compact, rugged and efficient master cylinder concept, easily manufactured and maintained, as well as presenting considerable ease and fastness for assembling on the production line, avoiding assembly faults due to the fact that of its components are the same for all chambers and in a smaller number. Due to this, costs are facilitated and reduced during all the production cycle, from the design up to the end consumer, including a better maintenance during all the master cylinder useful life. This can be achieved because this new tandem master cylinder concept, due to its simplified configuration, uses simpler and standard internal and external components for all chambers on the master cylinder, facilitating its manufacturing, maintenance and assembly.

As for the configuration characteristics, regarding the master cylinder assembly, there is also the advantage of replacing the conventional spring ring, generally manufactured from spring steel, with a ring sealing as an O-ring type, or similar, made with elastomer material as neoprene, or thermoplastic elastomer, easily found on the market, which is sufficient to maintain the master cylinder characteristics with their assembled components until the moment to install the master cylinder on the servo brake of the vehicle brake system. This is due its simplified configuration, facilitating the cylinder manufacturing without compromising its operation, its efficiency, and the brake system safety.

Also regarding the configuration aspect, this new master cylinder allows the replacement of current servo brakes with longer body, projected for master cylinders with long stroke type or even to short or standard stroke by a compact standard type servo brake, which has lower production costs and uses standard components, and yet eliminates the risk potential for leaks, avoiding the migration of brake fluid into the servo brake.

In addition to the above described, it is worth mentioning the significant cost reduction, since its configuration allows the riddance of the sealing sphere, reducing manufacturing time and machining operation, and eliminating the sphere swaging operation; as well as simplifying the factory layout and the housing flow on the machining line and master cylinder production.

Regarding the functional aspect and the effects felt by the vehicle driver, it is worth to mention the reduction on the long pedal stroke sensation and the felling of no brake application. This sensation/feeling is felt by the

vehicle driver when a fault occurs in one of the two chambers of the double master cylinder. This sensation is real, can be observed currently on every vehicle brake systems, and it is due to the inherent characteristics of a design with tandem pressure chambers. In this context, there is also a release/reduction of the brake pedal effort, when compared to the current single master cylinder and/or double master cylinder with tandem chambers. The effort compensation is done through the area reduction of each parallel chamber, when a failure occurs in any pressure chamber.

On the grounds of the above mentioned factors, grouped together with the master cylinder utilization being proposed here, there is yet a cost reduction, both on the manufacturing process by means of the reduction of the housing machining, and on the assembly process by means of the simplification and ease of the whole assembly of the master cylinder.

Therefore, by the configuration characteristics and operation described above, it is possible to note clearly that the "MASTER CYLINDER FOR AUTOMOTIVE VEHICLE BRAKE SYSTEMS" is a new concept for the state of the art, and it is invested of novelty, inventive act and reproducibility conditions, which deserve the Invention Patent Privilege.