Master brake cylinder, braking system

Patent metadata

Field	Value
Publication number	US-11084475-B2
Application number	US-201716464997-A
Country	US
Kind code	B2
Filing date	Oct 5, 2017
Priority date	Nov 30, 2016
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

A master brake cylinder is described for a brake system of a motor vehicle as having a hydraulic cylinder that has a plurality of hydraulic connections, in which at least one hydraulic piston is mounted so as to be displaceable axially in a direction of actuation and in a relief direction, the hydraulic piston being displaceable against the force of a spring element in the direction of actuation, the hydraulic piston having at least one lateral wall opening that, in at least one sliding position, opens into an inner chamber of the hydraulic cylinder. It is provided that the lateral wall opening is assigned an elastically deformable sealing ring that on its inner side is fastened on the hydraulic piston and on its outer side is pre-loaded against the hydraulic cylinder by its inherent elasticity and is shaped such that when the hydraulic piston is displaced in the direction of actuation it detaches from the hydraulic cylinder, and when the hydraulic piston is displaced in the relief direction it bears on the hydraulic cylinder.

First claim

What is claimed is:

1. A master brake cylinder for a brake system of a motor vehicle, comprising:
a hydraulic cylinder that includes a plurality of hydraulic connections;
a spring element;
an elastically deformable sealing ring; and
a hydraulic piston mounted in at least one of the hydraulic connections so as to be displaceable axially in an actuation direction and in a relief direction into a plurality of sliding positions;
wherein:
the hydraulic piston is displaceable in the actuation direction against a force of the spring element;
the hydraulic piston includes at least one lateral wall opening that, in at least one of the sliding positions, provides a hydraulic connection into an inner chamber of the hydraulic cylinder;
an inner side of the elastically deformable sealing ring is fastened on the hydraulic piston;
an outer side of the elastically deformable sealing ring is preloaded against the hydraulic cylinder by an inherent elasticity of the elastically deformable sealing ring;
in at least one of the plurality of sliding positions, the hydraulic cylinder, the hydraulic piston, and the sealing ring are arranged relative to each other in a manner that forms a damping chamber, with the sealing ring separating the damping chamber and the inner chamber from each other, the inner chamber being, relative to the actuation direction, at a downstream side of the sealing ring and the damping chamber being, relative to the actuation direction, at an upstream side of the sealing ring;
displacement of the hydraulic piston in the actuation direction reduces a volume of the inner chamber and enlarges a volume of the damping chamber, which causes the elastically deformable sealing ring to detach from the hydraulic cylinder; and
displacement of the hydraulic piston in the relief direction enlarges the volume of the inner chamber and reduces the volume of the damping chamber, which causes the elastically deformable sealing ring to bear on the hydraulic cylinder.

2. The master brake cylinder as recited in claim 1 , wherein the sealing ring has one of a U-shaped cross-section and a V-shaped cross-section.

3. The master brake cylinder as recited in claim 1 , wherein the at least one lateral wall opening includes a first lateral wall opening, and the elastically deformable sealing ring is fastened on the hydraulic piston in front of the first lateral wall opening, seen in the direction of actuation.

4. The master brake cylinder as recited in claim 3 , wherein the at least one lateral wall opening additionally includes a second lateral wall opening, the first lateral wall opening opens into a portion of the inner chamber that is in the hydraulic piston into which the second lateral wall opening also opens, and the second lateral wall opening is at an axial distance from the first lateral wall opening, such that, in at least one of the sliding positions of the hydraulic piston, the second lateral wall opening is connected to a relief chamber of the hydraulic cylinder.

5. The master brake cylinder as recited in claim 4 , wherein the second lateral wall opening is situated in the hydraulic piston in such a way that the connection to the relief chamber does not arise until the hydraulic piston is in a position close to an end position of the hydraulic piston in the relief direction.

6. The master brake cylinder as recited in claim 3 , wherein the first lateral wall opening is closed by the hydraulic cylinder in or shortly before an end position of the hydraulic piston.

7. The master brake cylinder as recited in claim 1 , wherein the hydraulic piston is made without steps at least on a longitudinal segment situated inside the hydraulic cylinder.

8. The master brake cylinder as recited in claim 1 , wherein the hydraulic piston has at least one circumferential annular groove in which the elastically deformable sealing ring lies in some regions.

9. A brake system for a motor vehicle, comprising:
at least one hydraulic circuit that has at least one hydraulically actuatable wheel brake; and
a master brake cylinder that is connected to the at least one hydraulic circuit, wherein the master brake cylinder includes:
a hydraulic cylinder;
a spring element;
an elastically deformable sealing ring; and
a hydraulic piston mounted in at least one of the hydraulic connections so as to be displaceable axially in an actuation direction and in a relief direction into a plurality of sliding positions;

wherein:
the hydraulic piston is displaceable in the actuation direction against a force of the spring element;
the hydraulic piston includes at least one lateral wall opening that, in at least one of the sliding positions, provides a hydraulic connection into an inner chamber of the hydraulic cylinder;
an inner side of the elastically deformable sealing ring is fastened on the hydraulic piston;
an outer side of the elastically deformable sealing ring is preloaded against the hydraulic cylinder by an inherent elasticity of the elastically deformable sealing ring;
in at least one of the plurality of sliding positions, the hydraulic cylinder, the hydraulic piston, and the sealing ring are arranged relative to each other in a manner that forms a damping chamber, with the sealing ring separating the damping chamber and the inner chamber from each other, the inner chamber being, relative to the actuation direction, at a downstream side of the sealing ring and the damping chamber being, relative to the actuation direction, at an upstream side of the sealing ring;
displacement of the hydraulic piston in the actuation direction reduces a volume of the inner chamber and enlarges a volume of the damping chamber, which causes the elastically deformable sealing ring to detach from the hydraulic cylinder; and
displacement of the hydraulic piston in the relief direction enlarges the volume of the inner chamber and reduces the volume of the damping chamber, which causes the elastically deformable sealing ring to bear on the hydraulic cylinder.

10. A master brake cylinder for a brake system of a motor vehicle, comprising:
a hydraulic cylinder;
a spring;
an elastically deformable sealing ring; and
a hydraulic piston mounted in the hydraulic cylinder so as to be displaceable axially in an actuation direction against a force of the spring and to be displaceable axially in an opposite relief direction;
wherein:
the hydraulic piston includes at least one lateral wall opening that, in at least one axial position of the hydraulic piston, provides a hydraulic connection into an inner chamber of the hydraulic cylinder;
an inner side of the elastically deformable sealing ring is fastened on the hydraulic piston;
an outer side of the elastically deformable sealing ring is preloaded against the hydraulic cylinder by an inherent elasticity of the elastically deformable sealing ring; and
the elastically deformable sealing ring is shaped such that, when there is a displacement of the hydraulic piston in the actuation direction, the elastically deformable sealing ring detaches from the hydraulic cylinder and, when there is a displacement of the hydraulic piston in the relief direction, the elastically deformable sealing ring bears on the hydraulic cylinder;
one of the at least one lateral wall opening:
opens into a portion of the inner chamber of the hydraulic cylinder partly bounded by the elastically deformable sealing ring when the hydraulic piston is in the at least one axial position; and
cannot open into the portion of the inner chamber of the hydraulic cylinder partly bounded by the elastically deformable sealing ring when the hydraulic piston is not in the at least one of axial position; and

wherein one or more of the following five fea

Assignees

• Bosch Gmbh Robert

Inventors

• Anderson Chris
• Foerch Dirk
• Yvonet Florent
• Sprocq Raynald
• Hansmann Simon
• Kistner Matthias

Classifications

• F15B15/1452

  Piston sealings · CPC title

• F16J15/3236

  with at least one lip for each surface, e.g. U-cup packings · CPC title

• F15B7/08

  Input units; Master units · CPC title

• B60T11/236 Primary

  Piston sealing arrangements · CPC title

• B60T13/145

  Master cylinder integrated or hydraulically coupled with booster · CPC title