GB1584748A

GB1584748A - Brake fluid reservoirs

Info

Publication number: GB1584748A
Application number: GB4424077A
Authority: GB
Original assignee: Automotive Products PLC
Current assignee: Automotive Products PLC
Priority date: 1977-10-25
Filing date: 1977-10-25
Publication date: 1981-02-18
Also published as: JPS5845968Y2; JPS5468087U; IN148092B

Description

(54) BRAKE FLUID RESERVOIRS (71) We, AUTOMOTIVE PRODUCTS LIMITED, a British Company of Tachbrook Road, Leamington Spa, Warwickshire, CV31 3ER do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to fluid reservoirs for hydraulic dual circuit braking systems.

In dual circuit braking systems it is common for the fluid reservoir to have a separate chamber for each circuit. It is usual for these reservoirs to be separated by a partition wall, and for the two chambers to be interconnected above a predetermined level of brake fluid in the reservoir, so as to allow a continuous equalisation of air and fluid. Hence, it is typical for the reservoir to be constructed of a single plastic unit with a central partition forming a weir, which divides the unit into two chambers below the predetermined fluid level. This construction has the disadvantage that in the event of a fluid leak from one braking circuit and the emptying of its feed chamber in the reservoir, then as the vehicle moves over rough ground, accelerates or brakes, the fluid in the other chamber will have sufficient inertia to splash over the weir into the empty chamber.

Therefore the still good circuit will be slowly deprived of fluid from its reservoir chamber.

The object of the present invention is to provide a duel circuit fluid reservoir that minimises the above problem.

According to this invention there is provided a brake fluid reservoir for a dual circuit braking system and comprising a reservoir body having two chambers chargeable with fluid and which are interconnected, for the flow of fluid from one chamber to the other, through a float controlled valve means which substantially closes against fluid flow when a minimum desired fluid level in the reservoir pertains.

Preferably the two chambers are each connected to the vertical tube having a float therein by a corresponding aperture which is located at the minimum desired fluid level.

Conveniently. the float is cylindrical and is guided in the tube to act as the valve closure.

It is preferable for the tube to be integral with a partition wall located between the two chambers, and preferably the tube is located so that it is external of the reservoir chambers and the wall of the tube is integral with the partition wall and the external wall of the reservoir body.

The invention will now be described by way of example and with reference to the accompanying drawings in which: Fig. 1 is a longitudinal section of a fluid reservoir according to this invention; Fig. 2 is a view of the reservoir in Fig. 1 in the direction of arrow A; and Fig. 3 is a section on the line III-III in Fig. 1.

With reference to Figs. 1, 2 and 3 the fluid reservoir comprises a reservoir body 11 having two separate chambers 12 and 13, each of which are connected by outlets, 14 and 15 respectively, to a separate brake circuit (not shown). The two chambers 12 and 13 are separated by a partition wall 16, and each chamber has a screw connectable filler inlet 17 and 18, respectively, through which fluid is introduced into the chambers.

Each inlet is normally covered by a screwthreaded closure (not shown).

The partition wall 16 is integral with the two longitudinal side walls of the reservoir body 11, one end 19 of the partition wall 16 being integral with a portion of the side wall of the reservoir which also forms a common wall 20 with a vertical tube 21 external of the chambers 12 and 13. The vertical tube 21 is arranged so that portions of its common wall 20, with the side wall, lie on both sides of the partition wall 16.

Two apertures, 22 and 23, are arranged such that each aperture, 22 or 23, connects one of the two chambers 12 or 13 respectively with the tube 21 so that the chambers 12 and 13 are connected through the tube 21. The apertures 22 and 23 are located at approximately the minimum desirable fluid level which should exist in each chamber.

A float 24 is slideably guided within the tube 21 and when a minimum fluid level pertains, the float 24 will substantially close the apertures 22 and 23 and hence the connection between the fluid chambers. The floor 25 of the tube 21 is a flat floor adjacent the apertures and is formed as a part of the peripheral rim of the lower part 26 of the fluid reservoir.

The fluid reservoir is formed from two plastics injection moulded parts, an upper part 27 and a lower part 26. The plastics materials usually utilised for injection moulding the reservoirs are high density polyethylene and, alternatively, polypropylene. Both parts 26 and 27 have an outer peripheral flange 29 which is utilised for welding the two parts 26 and 27 together. The partition wall 16 comprises two halves, one half associated with each of the upper or lower parts of the reservoir. The two halves of the partition wall 16 are butt welded together.

The horizontal split line between the upper and lower parts of the reservoir corresponds approximately with the minimum desired fluid level.

The tube 21 has its floor 25 at the horizontal split line such that the vertical section of the tube 21 and its top end wall 28 are integrally moulded with the upper part 27 of the reservoir and the floor 25 of the tube which is adjacent the apertures 22 and 23, is formed as an extension of the peripheral flange 29 associated with the lower part 26 of the reservoir. The floor 25 is welded to the tube 21 during the assembly of the upper and lower parts of the reservoir.

During normal operation the brake fluid reservoir is filled with fluid such that each chamber 12 and 13, has between a maximum and minimum desired level of fluid within it. If for example the brake circuit connected to chamber 13 develops a fluid leak, chamber 13 will empty and chamber 12 will also empty, via aperture 22, tube 21, and aperture 23 since the float 24 will be held above the apertures by the fluid. This continues until the fluid level in chamber 12 is reduced to the desired minimum level add the float falls until it rests on the floor 25 of the tube 21. With the float in this position, the aperture 22 and 23 are closed and any splash, caused by surging movements of the fluid and vibrations, cannot pass into chamber 13.Should the car be positioned on a steep incline for some time, such that the fluid moves so that the aperture 22 becomes temporarily submerged then obviously some fluid will trickle through to the now empty chamber 12.

However, the object of the invention is to reduce the fluid loss caused by fluid surges, and splash caused by vibrations, and thus minimise fluid transfer between the partially full and empty chambers.

WHAT WE CLAIM IS: 1. A brake fluid reservoir for a dual circuit braking system and comprising a reservoir body having two chambers chargeable with fluid and which are interconnected, for the flow of fluid from one chamber to the other, through a float controlled valve means which substantially closes against fluid flow when a minimum desired fluid level in the reservoir pertains.

2. A brake fluid reservoir as claimed in Claim 1, wherein the two chambers are each connected to a vertical tube having a float therein, by a corresponding aperture which is located at the minimum desired fluid level.

3. A brake fluid reservoir as claimed in Claim 3, wherein the float is cylindrical and is guided in the tube to act as the valve closure.

4. A brake fluid reservoir as claimed in Claim 2 or Claim 3, wherein the tube is integral with a partition wall located between the two chambers.

5. A brake fluid reservoir as claimed in Claim 4, wherein the tube is external of the reservoir chambers and the wall of the tube is integral with the partition wall and an associated external wall of the reservoir body.

6. A brake fluid reservoir as claimed in Claim 4 or Claim 5, wherein the reservoir comprises two parts, an upper part and a lower part which are welded together and the vertical tube is integral with the upper part and the floor of the tube is integral with the lower part.

7. A brake fluid reservoir as claimed in Claim 6, wherein the minimum desired fluid level line corresponds with the join line between the upper and lower parts.

8. A brake fluid reservoir substantially as described herein and as shown in the accompanying drawings. - -

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. A float 24 is slideably guided within the tube 21 and when a minimum fluid level pertains, the float 24 will substantially close the apertures 22 and 23 and hence the connection between the fluid chambers. The floor 25 of the tube 21 is a flat floor adjacent the apertures and is formed as a part of the peripheral rim of the lower part 26 of the fluid reservoir. The fluid reservoir is formed from two plastics injection moulded parts, an upper part 27 and a lower part 26. The plastics materials usually utilised for injection moulding the reservoirs are high density polyethylene and, alternatively, polypropylene. Both parts 26 and 27 have an outer peripheral flange 29 which is utilised for welding the two parts 26 and 27 together. The partition wall 16 comprises two halves, one half associated with each of the upper or lower parts of the reservoir. The two halves of the partition wall 16 are butt welded together. The horizontal split line between the upper and lower parts of the reservoir corresponds approximately with the minimum desired fluid level. The tube 21 has its floor 25 at the horizontal split line such that the vertical section of the tube 21 and its top end wall 28 are integrally moulded with the upper part 27 of the reservoir and the floor 25 of the tube which is adjacent the apertures 22 and 23, is formed as an extension of the peripheral flange 29 associated with the lower part 26 of the reservoir. The floor 25 is welded to the tube 21 during the assembly of the upper and lower parts of the reservoir. During normal operation the brake fluid reservoir is filled with fluid such that each chamber 12 and 13, has between a maximum and minimum desired level of fluid within it. If for example the brake circuit connected to chamber 13 develops a fluid leak, chamber 13 will empty and chamber 12 will also empty, via aperture 22, tube 21, and aperture 23 since the float 24 will be held above the apertures by the fluid. This continues until the fluid level in chamber 12 is reduced to the desired minimum level add the float falls until it rests on the floor 25 of the tube 21. With the float in this position, the aperture 22 and 23 are closed and any splash, caused by surging movements of the fluid and vibrations, cannot pass into chamber 13.Should the car be positioned on a steep incline for some time, such that the fluid moves so that the aperture 22 becomes temporarily submerged then obviously some fluid will trickle through to the now empty chamber 12. However, the object of the invention is to reduce the fluid loss caused by fluid surges, and splash caused by vibrations, and thus minimise fluid transfer between the partially full and empty chambers. WHAT WE CLAIM IS:

1. A brake fluid reservoir for a dual circuit braking system and comprising a reservoir body having two chambers chargeable with fluid and which are interconnected, for the flow of fluid from one chamber to the other, through a float controlled valve means which substantially closes against fluid flow when a minimum desired fluid level in the reservoir pertains.