Pressure change damper for a hydraulic vehicle brake system with brake force control, and hydraulic vehicle brake system with brake force control with such a pressure change damper

Abstract

A pressure change damper for a pressure side of a hydraulic pump of a hydraulic vehicle brake system with brake force control includes a valve assembly. The valve assembly is fitted in the pressure change damper and has a tubular valve that defines a lip of a damper element between the valve assembly and a damper housing pressed into the valve housing. The valve housing and a tubular valve seat part are produced by forming.

Claims

1. A pressure change damper, comprising: a tubular damper housing open at one end; a tubular damper element open at one end, the damper element comprised of an elastic material and arranged in the damper housing, the open end of the damper element held sealing on or in the open end of the damper housing; and a valve assembly including (i) a tubular valve housing arranged at the open end of the damper housing and (ii) a valve arranged in the valve housing, the valve having a tubular valve seat part and a valve seat that is pressed into the valve housing, wherein the valve housing has a widening configured as a receiver for the open end of the damper housing, the widening configured by forming of the valve housing.

2. The pressure change damper according to claim 1, wherein the valve seat is configured as a constriction by forming of the valve seat part.

3. The pressure change damper according to claim 1, wherein the valve housing has beads in the axial plane, except in the region of the widening forming the receiver for the open end of the damper housing.

4. The pressure change damper according to claim 1, wherein both the valve housing and the valve seat part are configured by forming.

5. The pressure change damper according to claim 1, wherein: the receiver of the valve housing for the open end of the damper housing is a tubular collar which transforms into a circumferential channel with which the collar transforms into the tubular valve housing, the circumferential channel of the valve housing together with the open end of the damper housing forms a circumferential groove which tapers to a groove opening, and the tubular damper element has a circumferential lip on its open end which lies in the groove between the valve housing and the damper housing and which is thicker than the groove opening.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features of the disclosure arise from the description below of an embodiment of the disclosure in conjunction with the claims and the drawing. The individual features may be implemented alone or together in arbitrary combination as embodiments of the disclosure. The only FIGURE shows an axial section of a pressure change damper according to the disclosure.

DETAILED DESCRIPTION

(2) The pressure change damper 1 according to the disclosure, shown in the drawing, has a tubular damper housing 2 with an open end and a closed end, which can also be described as dome-like. A hose-like damper element 3 is arranged in the damper housing 2 and also has an open end and a closed end. The damper element 3 consists of an elastic material, in this embodiment an elastomer, which is foamable. It is elastically deformable and may also be compressible, i.e. elastically changeable in volume or wall thickness. The damper element 3 has an almost cylindrical, slightly tapering cavity 4 which extends from the open end over around of its length. In the longitudinal direction, approximately at level with one end of the cavity 4, the damper element 3 tapers outwardly at its closed end into a truncated cone with a circumferential undulation 5. An outer diameter of the damper element 3 is smaller than an inner diameter of the damper housing 2, so that the damper element 3 is surrounded by an intermediate space 6 in the damper housing 2. At the open end, the damper element 3 has a circumferential lip protruding obliquely towards the outside, with an approximately circular ring cross-section. A wall thickness of the damper element 3 is thinnest at a transition 8 from the lip 7 to a hose-like part at the open end of the damper element 3.

(3) The damper element 1 has a valve assembly 9 which is arranged axially at the open end of the damper housing 2. The valve assembly 9 has a tubular valve housing 10 with a smaller diameter than the damper housing 2. At an end on the damper housing side, the valve housing 10 has a diameter widening as a receiver 11 for the open end of the damper housing 2. The receiver 11 has the form of a tubular collar in which the open end of the damper housing 2 can be pushed or pressed. A transition from the tubular collar 11 to a tubular part of the valve housing 10 with smaller diameter takes the form of a circumferential channel 12. The collar forming the receiver 11 for the open end of the damper housing 2, and the circumferential channel 12 of the otherwise tubular valve housing 9, are produced by forming, for example by deep drawing, wherein in this embodiment the valve housing 10 as a whole is produced by forming, in particular deep drawing. Together with the open end of the damper housing 2, the receiver 11 in the form of a tubular collar, and the circumferential channel 12 of the valve housing 10 adjacent thereto, form a circumferential groove in which the lip 7 lies at the open end of the damper element 3. The groove reduces in cross-section in the direction of an inwardly directed groove opening (at 8) which forms the narrowest point, so that the lip 7 is held in the circumferential groove between the open end of the damper housing 2 and the receiver 11 and the circumferential channel 12. The open end of the damper element 3 is thus held on or in the open end of the damper housing 2, and the intermediate space 6 which surrounds the damper element 3 in the damper housing 2 is closed and sealed.

(4) A tubular valve seat part 13 is pressed into the valve housing 10 and, at its end facing the damper element 3, tapers in the manner of a hollow truncated cone finishing in a short tubular collar. An inside of the frustoconical constriction forms a valve seat 14 for a flow control valve 15 arranged in the tubular valve seat part 13. The constriction forming the valve seat 14 is produced by forming, for example by deep drawing, wherein in this embodiment, the valve seat 13 as a whole is produced by forming, in particular deep drawing. In comparison with a valve seat produced by material removal, the valve seat 14 produced by forming has a significantly higher quality and tightness at a fraction of the production cost.

(5) On the outside, the valve housing 10 has beads 16 at the transition from the tubular part to the circumferential channel 12. The beads 16 bridge a peripheral chamfer at the transition from the groove 12 to the tubular part of the valve housing 10, and stiffen the valve housing 10 and the channel 12. The beads 16 are arranged in axial planes.

(6) The flow control valve 15 has a hollow shut-off body 17 which is pressed with pretension against the valve seat 14 by a valve spring 18. In this embodiment, the valve spring 18 is a coil compression spring which rests on a tubular spring holder 19 which presses the valve seat 14 into the valve seat part 13. The shut-off body 17 of the flow control valve 15 has an axial through hole with a frustoconical constriction, which forms a valve seat 20 of a check valve 21. A ball is received in the through hole of the shut-off body 17 of the flow control valve 15 as the shut-off body 22 of the check valve 21. In the embodiment shown, the check valve 21 is unsprung, however a spring-loaded check valve is also possible (not shown).

(7) Next to the open end, the damper housing 2 is formed as a caulking sleeve 23 for a self-clinch connection. For this, on the outside close to its open end, the damper housing 2 has a circumferential groove 24 with rounded groove cross-section, of which the rear groove flank 25 in the pressing direction is arranged in a radial plane of the damper housing 2 and protrudes to the outside. On pressing into a receiver 26 of a hydraulic block 27, the groove flank 25 deforms the material surrounding the receiver 27 of the hydraulic block 27 plastically into the groove 24 of the caulking sleeve 23, so the damper housing 22 is held mechanically stably in the hydraulic block 27 and is sealed pressure-tightly in the receiver 26.

(8) The receiver 26 in the hydraulic block 27 is a blind hole of stepped diameter, wherein when the damper housing 2 is pressed in, the valve housing 10 arranged at its open end is pressed into a smaller diameter axial extension 28 of the receiver 26 and hence sealed on the periphery.

(9) The hydraulic block 27, of which the drawing shows only a fraction surrounding the receiver 26 for the pressure change damper 1, is part of a brake force controller of a hydraulic vehicle brake system which is not otherwise shown. The hydraulic block 27 has further receivers for hydraulic elements of the brake force controller such as the hydraulic accumulator, solenoid valves and hydraulic pumps, and ports for brake lines to a brake master cylinder and to wheel brakes (not shown). The hydraulic elements and the ports for the brake lines are connected together hydraulically by the bores of the hydraulic block 27. Such hydraulic blocks of vehicle brake systems with brake force control are known to the person skilled in the art and not explained in more detail here. In manners known in themselves, the brake force controllers may be used for anti-lock braking, traction control, skid protection and electronic stability control, automatic braking and adaptive cruise control, for which the normal abbreviations are ABS, ASR, FDR, ESP, ACC. The list is exemplary and not conclusive.

(10) A supply line 29 formed as an oblique bore in the hydraulic block 27 opens at a ring step between the smaller diameter extension 28 of the receiver 26 for the pressure change damper 1 and the receiver 26, and communicates through radial holes 30 in the valve housing 10 with the cavity 4 of the damper element 3. The holes 30 are arranged in the valve housing 10 distributed over a circumference between the valve seat 14 and the circumferential channel 12. The pressure change damper 1 communicates with a hydraulic pump (not shown), in particular a piston pump of the brake force controller, via the supply line 29. The pressure change damper 1 damps pressure pulsations in the brake fluid which are caused by a piston pump because of its oscillating pumping manner.

(11) Via the check valve 19 and the flow control valve 15, the cavity 4 in the damper element 3 communicates with an outlet 31 configured as an axially parallel bore which opens eccentrically into a base of the extension 28 of the receiver 26 for the pressure change damper 1, and transforms into a transverse bore. In the embodiment of the disclosure shown, the check valve 19 and the flow control valve 15 are outlet valves of the pressure change damper 1.