Single Reversible Hydraulic Pump for Continuously Variable Transmission

Solution Overview

Problem

Existing hydraulic control apparatuses for continuously variable transmissions require two electric hydraulic pumps, leading to complex structures and increased costs, which are not efficiently managed in terms of energy consumption and gear ratio control.

Innovation Solution

A hydraulic control apparatus with a single electric reversible hydraulic pump and a closed circuit configuration, utilizing check valves and a control valve to manage hydraulic oil flow and pressure, allowing for efficient gear ratio control and energy conservation by reducing the number of pumps and simplifying the structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If two electric hydraulic pumps are installed to ensure required hydraulic pressure under all conditions, then energy efficiency is improved, but device complexity and cost increase

Engineering Contradiction:

Improveenergy efficiencyVSAvoidstructure complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent combines two separate electric hydraulic pumps into a single reversible hydraulic pump that can pump hydraulic oil in both directions. This merging reduces the number of pumps from two to one, simplifying the device structure and reducing cost while maintaining the capability to supply hydraulic pressure to both the drive pulley and driven pulley under all operating conditions

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The reversible hydraulic pump serves multiple functions: it can pump hydraulic oil to the drive pulley, to the driven pulley, or to both simultaneously by reversing its pumping direction. This multi-functionality replaces the need for two separate pumps, reducing device complexity while maintaining energy efficiency

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Use of energy by moving object

If two electric hydraulic pumps are installed to ensure required hydraulic pressure under all conditions, then energy efficiency is improved, but manufacturing cost increases

Engineering Contradiction:

Improveenergy efficiencyVSAvoidmanufacturing cost

Core Design Contradiction:

Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent combines two separate electric hydraulic pumps into a single reversible hydraulic pump that can pump hydraulic oil in both directions. This merging reduces the number of pumps from two to one, simplifying the device structure and reducing cost while maintaining the capability to supply hydraulic pressure to both the drive pulley and driven pulley under all operating conditions

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The reversible hydraulic pump serves multiple functions: it can pump hydraulic oil to the drive pulley, to the driven pulley, or to both simultaneously by reversing its pumping direction. This multi-functionality replaces the need for two separate pumps, reducing device complexity while maintaining energy efficiency

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If a single electric reversible hydraulic pump is used to simplify structure and reduce cost, then device complexity is reduced, but reliability of hydraulic pressure supply may worsen

Engineering Contradiction:

Improvestructure simplicityVSAvoidhydraulic pressure supply reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The reversible hydraulic pump dynamically changes its pumping direction based on control signals from the control valve. The pump can switch between pumping to the drive pulley, pumping to the driven pulley, or pumping to both, allowing the system to adapt to different operating conditions and maintain reliable hydraulic pressure supply

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control valve receives control signals and adjusts the pumping direction of the reversible hydraulic pump accordingly. This feedback mechanism ensures that the single pump can reliably supply hydraulic pressure to the appropriate pulley under all operating conditions, maintaining system reliability

Inventive Principle:

Principle #23Feedback

4Use of energy by moving object

If check valves and bypass passages are added to enable single pump operation, then device complexity increases slightly, but energy efficiency improves significantly

Engineering Contradiction:

Improveenergy efficiencyVSAvoidhydraulic circuit complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The control valve acts as an intermediary between the reversible hydraulic pump and the hydraulic actuators. It receives control signals and directs the pump's output to the appropriate circuit (drive pulley or driven pulley), enabling the single pump to efficiently control hydraulic pressure distribution without requiring complex circuit modifications

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the direction control function from the pump itself and places it in the control valve system. By using check valves and bypass passages in combination with the control valve, the system separates the pumping function from the direction control function, allowing the pump to operate efficiently while the valve system manages hydraulic oil flow distribution

Inventive Principle:

Principle #2Taking out (Extraction)

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

The solution enables reliable gear ratio adjustment and energy conservation by using a single pump, simplifying the structure, reducing costs, and ensuring efficient hydraulic oil retention, thus improving energy efficiency and reducing shifting time.

Implementation Method 1

a single electric reversible hydraulic pump (84) installed at a common portion (42a3) of the first oil passage (42a1) and the second oil passage (42a2) and capable of pumping hydraulic oil retained in the reservoir (82) and delivering to the first oil passage (42a1) or the second oil passage (42a2)

Methodology Applied

Scientific EffectHydraulic pressure: Pressure Gradient

Implementation Method 2

a first check valve (90) installed in the first oil passage (42a1) between the reservoir (82) and the hydraulic pump (84) for blocking flow of hydraulic oil from the hydraulic pump (84) to the reservoir (82)

Methodology Applied

Scientific EffectCheck valve flow blocking: Valve

Data Source

PatentUS8857382B2Hydraulic control apparatus for continuously variable transmission

Publication Date: 2014.10.14 HONDA MOTOR CO LTD

AI summary

In a hydraulic control apparatus for a continuously variable transmission that enables gear ratio variation by controlling supply of hydraulic oil to first and second hydraulic actuators, there are provided with first and second oil passages connecting the first and second actuators to a reservoir, a single electric hydraulic pump installed at a common portion thereof, first and second check valves installed in the first and second oil passages for blocking flow of hydraulic oil to the reservoir, first and second bypass passages formed in the first and second oil passages, a control valve installed therebetween, a fourth check valve installed in the first and second bypass passages for blocking flow of hydraulic oil to the hydraulic pump, and a controller for controlling these, thus readily enabling a configuration that reduces the number of electric hydraulic pumps to one and minimizes cost increase.