Coolant Pump Control Slide with Sealed Pressure Chambers

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Solution Overview

Problem

Coolant pumps for internal combustion engines face challenges in minimizing leakage flow between the control slide's front and rear sides, requiring precise and low-friction adjustment with minimal actuating forces, while ensuring reliable sealing and reduced frictional forces.

Innovation Solution

The control slide features inner and outer hollow-cylindrical peripheral walls with radial grooves and PTFE sealing rings, connected via a base to create separate pressure chambers, allowing displacement based on pressure differences and guiding the slide with reduced friction, eliminating the need for return springs and enhancing tightness with oblique slots and machined surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a control slide is used to regulate coolant flow, then coolant flow regulation is improved, but leakage flow between front and rear sides increases

Engineering Contradiction:
Improvecoolant flow regulationVSAvoidleakage flow
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The control slide is divided into functionally distinct regions: an inlet side region with a first sealing ring and an outlet side region with a second sealing ring. This segmentation allows each sealing ring to independently address leakage at different locations, effectively preventing coolant from bypassing the control slide while maintaining flow regulation capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Sealing rings are introduced as intermediary elements between the control slide and the housing bore. These sealing rings act as mediators that prevent direct leakage paths while allowing the control slide to move freely for flow regulation. The sealing rings transfer the sealing function from the control slide surface to dedicated sealing components.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If hydraulic pressure is used to adjust the control slide, then adjustment precision is improved, but frictional forces increase

Engineering Contradiction:
Improveadjustment precisionVSAvoidfrictional forces
Core Design Contradiction:
Measurement precisionVSForce

Solution Approach 1:

The mechanical friction-based adjustment system is replaced with a hydraulic actuation system. Instead of relying on mechanical forces that overcome friction, hydraulic pressure acts on the control slide through fluid pressure, enabling precise adjustment without being limited by frictional forces between the slide and housing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Hydraulic pressure is applied to the control slide to enable precise adjustment. The hydraulic system uses fluid pressure to move the control slide to desired positions, providing fine control capability while avoiding the high frictional forces that would occur with purely mechanical adjustment mechanisms.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Reliability

If sealing rings are added to prevent leakage, then sealing reliability is improved, but device complexity increases

Engineering Contradiction:
Improvesealing reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control slide is designed with multi-functionality: it serves both as the flow regulation element and as a mounting structure for the sealing rings. The inlet side region and outlet side region of the control slide each provide mounting locations for sealing rings, allowing a single component to fulfill multiple functions without adding separate sealing assemblies.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The sealing function is merged with the control slide structure by integrating sealing ring mounting features directly into the control slide. Instead of adding separate sealing mechanisms, the control slide itself incorporates grooves or surfaces for mounting sealing rings, combining the regulation and sealing functions in one component.

Inventive Principle:
Principle #5Merging (Combining)

4Speed

If the control slide is displaced hydraulically, then adjustment speed is improved, but actuating force requirements increase

Engineering Contradiction:
Improveadjustment speedVSAvoidactuating force
Core Design Contradiction:
SpeedVSForce

Solution Approach 1:

Hydraulic pressure is used to displace the control slide, leveraging the high force density of hydraulic systems. The hydraulic actuation provides both rapid response speed and sufficient actuating force simultaneously, as the incompressibility of hydraulic fluid enables fast movement while the pressure generation capability provides the necessary force to overcome any resistance.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The hydraulic system allows dynamic adjustment of pressure parameters to match the actuation requirements. By varying the hydraulic pressure, the system can achieve both high-speed adjustment (with higher pressure) and controlled movement (with lower pressure), providing flexibility in balancing speed and force requirements.

Inventive Principle:
Principle #35Parameter changes

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 minimizes leakage flow, ensures precise and low-friction adjustment with small actuating forces, and extends the service life of sealing rings, achieving reliable sealing and efficient coolant flow regulation.

Implementation Method 1

a first sealing ring is arranged in a radial groove on the radial inside of the inner hollow-cylindrical peripheral wall and a second sealing ring is arranged in a radial groove on the radial outside of the outer hollow-cylindrical peripheral wall

Methodology Applied
Scientific EffectSealing:

Implementation Method 2

the two peripheral walls are connected to one another via a base, which separates a first pressure chamber from a second pressure chamber, by which the control slide can be displaced as a function of a pressure difference between the two pressure chambers

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Implementation Method 3

ensures precise and low-friction adjustment with small actuating forces

Methodology Applied
Scientific EffectFriction reduction: Lubrication

Data Source

PatentEP3371430B1Coolant pump for an internal combustion engine
Publication Date: 2021.02.24 PIERBURG GMBH
  • EP3371430B1 patent drawingFigure 1~2

AI summary

Coolant pumps for internal combustion engines are known, comprising a drive shaft (18), a coolant pump impeller (20) which is rigidly arranged on the drive shaft (18) at least in a rotationally fixed manner and by means of which coolant can be pumped, and an adjustable control slide (58), by means of which a flow cross-section of an annular gap (62) between an outlet (64) of the coolant pump impeller (20) and the surrounding pump channel (12) can be regulated. In order to achieve a secure seal of the two opposing pressure chambers (92, 94) in particular during a purely hydraulic adjustment, the control slide (58) has an inner hollow cylindrical circumferential wall (84), on the radial inner face of which a radial groove (86) is formed, a seal ring (88) being arranged in said radial groove, and the control slide also has an outer hollow cylindrical circumferential wall (60), on the radial outer face of which a radial groove is formed (74), a seal ring (76) being arranged in said radial groove. The two circumferential walls (60, 84) are connected together via a base (80).