Camshaft Adjuster Stator Non-Return Valve Under-Pressure Compensation

Solution Overview

Problem

Existing camshaft adjusters face challenges in efficiently managing under-pressure phases, leading to unintended rotor movement and requiring large storage capacity and weight in all pressure chambers, which increases installation space and weight.

Innovation Solution

A stator design for the camshaft adjuster featuring a ring-shaped outer part with radial segments forming pressure chambers and a cavity connected via a non-return valve, allowing only a subset of pressure chambers to draw hydraulic fluid from a volume accumulator, reducing the need for extensive storage capacity and weight by compensating under-pressures effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If all pressure chambers are equipped with large storage capacity to compensate under-pressures, then reliability is improved, but weight and installation space increase

Engineering Contradiction:

Improveunder-pressure compensationVSAvoidstator weight

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The stator is divided into multiple segments, each forming a pressure chamber with the rotor vanes. This segmentation allows selective connection of individual pressure chambers to the volume accumulator via non-return valves, enabling distributed under-pressure compensation without requiring all chambers to have large storage capacity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A volume accumulator is introduced as an intermediary component that stores hydraulic fluid and supplies it to selected pressure chambers during under-pressure phases. The non-return valves act as intermediaries to control unidirectional flow from the accumulator to the pressure chambers, ensuring reliable compensation while minimizing required storage capacity in each chamber.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If all pressure chambers are equipped with large storage capacity to compensate under-pressures, then reliability is improved, but installation space increases

Engineering Contradiction:

Improveunder-pressure compensationVSAvoidstator installation space

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The stator is divided into multiple segments, each forming a pressure chamber with the rotor vanes. This segmentation allows selective connection of individual pressure chambers to the volume accumulator via non-return valves, enabling distributed under-pressure compensation without requiring all chambers to have large storage capacity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A volume accumulator is introduced as an intermediary component that stores hydraulic fluid and supplies it to selected pressure chambers during under-pressure phases. The non-return valves act as intermediaries to control unidirectional flow from the accumulator to the pressure chambers, ensuring reliable compensation while minimizing required storage capacity in each chamber.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Weight of stationary object

If fewer pressure chambers draw hydraulic fluid from the volume accumulator, then weight and installation space are saved, but under-pressure compensation effectiveness may be reduced

Engineering Contradiction:

Improvestator weightVSAvoidunder-pressure compensation effectiveness

Core Design Contradiction:

Weight of stationary objectVSReliability

Solution Approach 1:

The system utilizes hydraulic fluid flow controlled by non-return valves to compensate for under-pressures in selected pressure chambers. The hydraulic connection between the volume accumulator and the pressure chambers enables effective pressure equalization without requiring all chambers to be equipped with large storage capacity.

Inventive Principle:

Principle #29Pneumatics and hydraulics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design prevents unintended rotor movement by equalizing under-pressures in fewer pressure chambers, saving installation space and weight while ensuring fault-free operation through strategic placement and redundancy of non-return valves.

Implementation Method 1

a cavity (70) that is opened toward a pressure chamber (44) via a non-return valve (72)

Methodology Applied

Scientific EffectNon-return valve: Valve

Implementation Method 2

a volume accumulator with an accumulator connection (48) for storing a hydraulic fluid from the pressure chambers

Methodology Applied

Scientific EffectVolume accumulator: Hydraulic Accumulator

Implementation Method 3

the pressure chamber draws hydraulic fluid from the volume accumulator in the case of an under-pressure

Methodology Applied

Scientific EffectPressure equalization: Pressure Gradient

Data Source

PatentUS8776747B2Non-return valve of a camshaft adjuster

Publication Date: 2014.07.15 SCHAEFFLER TECHNOLOGIES AG & CO KG

AI summary

A stator (20) for a camshaft adjuster (4). The stator (20) has a ring-shaped outer part (50) for the concentric holding of a rotor (22) with vanes (34) that project in the axial direction and are arranged on the periphery around the rotor (22) and a segment (52) that projects inward in the radial direction from the ring-shaped outer part (50) for engaging between two vanes (34) of the rotor (22), in order to form, together with the two vanes (22), pressure chambers (44) of the camshaft adjuster (4). Here, the segment (52) has a cavity (70) for holding a hydraulic fluid from the pressure chambers (44).