Hydraulic Pressure Control Apparatus for Vehicular Power Transmission

Solution Overview

Problem

In hydraulic pressure control systems for vehicular power transmitting devices with lockup clutches, excessive hydraulic fluid discharge leads to reduced fluid flow to the oil pump, causing cavitation and vibration issues, especially at high temperatures and low temperatures, resulting in abnormal noises and reduced durability.

Innovation Solution

Incorporating a first orifice in the fluid passage upstream of the cooler and a second orifice in the lubrication passage, with the downstream side of the lubrication passage connected between the orifices and the cooler, to regulate fluid flow and ensure that the cooler and lubrication passages operate in series, thereby increasing the flowrate to the oil pump.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydraulic fluid is discharged from the pressure regulator valve to the upstream side of the oil pump, then the oil pump is lubricated and cooled, but excessive discharge causes reduced flowrate to the pump leading to cavitation and vibration

Engineering Contradiction:
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The hydraulic circuit is segmented into multiple paths: a first fluid passage for cooling (connected to cooler) and a second fluid passage for lubrication (connected to lubrication passage). The pressure regulator valve discharges excess hydraulic fluid to both passages, with the downstream side of the second passage connected to the first passage between the first orifice and the cooler. This segmentation allows independent control of cooling and lubrication flows while ensuring sufficient return flow to the pump.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first orifice (in the first fluid passage) and second orifice (in the second fluid passage) act as intermediaries that regulate the discharge flow from the pressure regulator valve. These orifices control the amount of hydraulic fluid discharged to each passage, preventing excessive discharge that would reduce the return flowrate to the oil pump and cause cavitation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If hydraulic fluid flows to the cooler and lubrication passage separately, then cooling and lubrication functions are provided, but excessive fluid discharge increases waste and reduces flow to the oil pump

Engineering Contradiction:
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The cooler and lubrication passage are merged into a series connection, where the downstream side of the second fluid passage (lubrication) is connected to the first fluid passage (cooling) between the first orifice and the cooler. This merging ensures that hydraulic fluid flows through both cooling and lubrication functions sequentially, providing both functions with the same fluid stream and reducing overall fluid waste while preventing excessive discharge.

Inventive Principle:
Principle #5Merging (Combining)

3Stress or pressure

If excessive hydraulic fluid is discharged from the safety valve, then pressure is regulated, but less fluid flows to the oil pump causing cavitation and abnormal noises

Engineering Contradiction:
Core Design Contradiction:
Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

The pressure regulator valve discharges only the necessary excess hydraulic fluid through controlled orifices to the first and second fluid passages, rather than allowing excessive discharge through the safety valve. This partial action approach regulates pressure while maintaining sufficient flow return to the oil pump, preventing cavitation and vibration.

Inventive Principle:
Principle #16Partial or excessive action

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 configuration enhances the flowrate of hydraulic fluid to the upstream side of the oil pump, reducing cavitation and vibration, and maintaining system durability by optimizing fluid distribution and minimizing waste.

Implementation Method 1

a first orifice is provided in the first fluid passage upstream of the cooler, and a second orifice is provided in the second fluid passage

Methodology Applied
Scientific EffectOrifice flow regulation:

Implementation Method 2

a first orifice is provided in the first fluid passage upstream of the cooler

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

a lubrication passage is connected to the first fluid passage downstream of the cooler

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentUS7669701B2Hydraulic pressure control apparatus for a vehicular power transmitting device
Publication Date: 2010.03.02
  • US7669701B2 patent drawing
  • US7669701B2 patent drawing
  • US7669701B2 patent drawing

AI summary

A first orifice is provided in a first fluid passage upstream of a cooler, and a second orifice is provided in a second fluid passage. The flowrates of hydraulic fluid flowing through the first and second fluid passages are regulated by the first and second orifices, respectively, and are thus suppressed from becoming excessive. Also, the downstream side of the second fluid passage is connected to the first fluid passage between the first orifice and the cooler, and a lubrication passage is connected to the first fluid passage downstream of the cooler. Accordingly, the lubrication passage is a single passage and the cooler and the lubrication passage are arranged in series so the cooler flowrate and the lubrication flowrate are the same. As a result, the flowrate of hydraulic fluid that flows out from a secondary regulator valve to the upstream side of an oil pump can be increased.