Vacuum brake servo for a motor vehicle braking system

摘要

A vacuum brake servo includes a force input element, a control valve actuated by the force input element, a vacuum chamber connected to a vacuum source, and an operating chamber which, depending on the actuation of the force input element, can be connected to either the vacuum chamber or the surrounding atmosphere. The control valve has a control piston that can be actuated by the force input element and, together with a valve element, forms a seal seat having a seal seat diameter between the operating chamber and the surrounding atmosphere. In the area close to the seal seat, a guide channel is provided. When the seal seat is opened, air from the surrounding atmosphere flows into the operating chamber. The guide channel extends axially with a constant flow diameter over a predetermined length, wherein the flow diameter is less than or equal to the seal seat diameter.

主权项

1. Vacuum brake booster for a motor vehicle brake system, comprising:
a rod-like force input member, which is coupled or can be coupled with a brake pedal, a control valve, which can be actuated by means of the force input member, a chamber arrangement having a vacuum chamber, which is connectable to a vacuum source, as well as a working chamber, which is, in accordance with the actuation of the force input member, selectively connectable to the vacuum chamber and to the surrounding atmosphere, wherein the control valve has a control piston actuatable by means of the force input member, which control piston forms together with a valve element, a sealing seat having a sealing seat diameter between the working chamber and the surrounding atmosphere, wherein in the region close to the sealing seat a guiding channel is provided through which, upon the opening of the sealing seat, air flows from the surrounding atmosphere into the working chamber due to a pressure difference, wherein the guiding channel extends in the axial direction with a constant flow diameter over a predetermined length, wherein the flow diameter is less than or equal to the sealing seat diameter, and wherein the predetermined length of the guiding channel lies between about 6 mm and 14 mm.