Stepping motor-driven control valve
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Solution Overview
Problem
Control valves driven by stepping motors in automotive air conditioners face challenges in compact size and cost due to translational movement of the rotor, which requires expensive bearings to manage reaction forces.
Innovation Solution
A control valve design that converts rotational movement of the rotor into translational movement of the valve actuating member without allowing rotational movement relative to the rotor, eliminating the need for expensive bearings by suppressing reaction forces in the axis line direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a stepping motor is used to precisely control the valve opening degree, then the control precision is improved, but the device size increases due to the translational movement of the rotor requiring expensive bearings
Solution Approach 1:
The patent replaces the traditional mechanical screw mechanism with a magnetic coupling system. The stepping motor's rotor generates a magnetic field that directly couples with the valve actuating member, eliminating the need for mechanical screw threads and bearings. This substitution of mechanical components with a magnetic field-based system achieves precise positional control while reducing motor size and eliminating expensive bearing requirements.
Solution Approach 2:
The patent introduces a magnetic coupling mechanism as an intermediary between the stepping motor rotor and the valve actuating member. This magnetic field mediator transmits rotational motion and force without direct mechanical contact, allowing the rotor to remain stationary while still driving the valve element. This intermediary approach resolves the contradiction by enabling precise control without the size penalty of traditional mechanical transmission components.
2Manufacturing precision
If a screw mechanism is used to convert rotational movement to translational movement, then the valve control precision is improved, but reaction forces in the axis line direction require expensive bearings
Solution Approach 1:
The patent eliminates the screw mechanism entirely by using magnetic coupling to transmit force. The rotor's magnetic field directly acts on the valve actuating member, converting rotational motion to translational movement of the valve element without mechanical screw threads. This substitution removes the source of reaction forces that would require expensive bearings, while maintaining precise control through the magnetic coupling mechanism.
Solution Approach 2:
The patent extracts and removes the problematic screw mechanism and bearing components from the system. By using magnetic coupling, the design takes out the mechanical transmission elements that generate reaction forces, leaving a simpler system that achieves the same functional goals without the complexity and cost of expensive bearings.
3Ease of operation
If the rotor is allowed to move translationally to drive the valve element, then the valve control is achieved, but the motor size increases
Solution Approach 1:
The patent uses magnetic coupling as an intermediary that allows the rotor to remain stationary while still transmitting force to move the valve actuating member. The magnetic field acts as a mediator that transfers energy and motion without requiring the rotor itself to translate, thus maintaining compact motor dimensions while achieving full valve control functionality.
Solution Approach 2:
The patent replaces the mechanical system where the rotor would physically translate with a magnetic field-based system. The rotor generates a magnetic field that couples with the valve actuating member, allowing force transmission without mechanical contact or rotor translation. This substitution maintains ease of operation while significantly reducing the required motor size.
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 design achieves a compact and cost-effective control valve operation by eliminating the need for expensive bearings, allowing precise adjustment of the valve opening degree using a stepping motor.
Implementation Method 1
a stepping motor, by which a rotational force can be generated in accordance with drive pluses supplied from a controller
Implementation Method 2
a screw mechanism is provided between the rotor and the valve actuating member
Data Source
Figure 1
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AI summary
A control valve 1 includes: an inlet port 110 for introducing a refrigerant from an upstream side; outlet ports 112 and 114 each for delivering the refrigerant toward a downstream side; a body 104 having valve holes 120 and 144 for communicating the inlet port 110 and the outlet ports 112 and 114 together, respectively; valve elements 130 and 132 for opening and closing valve sections by contacting and leaving the valve holes 120 and 144, respectively; a stepping motor having a rotor 172 for driving the valve elements 130 and 132 in the opening and closing directions of the valve sections; and a valve actuating member 134 that rotates with the rotor 172, and that drives the valve elements 130 and 132 in the opening and closing directions of the valve sections by converting a rotational movement of the rotor 172 around the axis line thereof into a translational movement of the valve actuating member in the axis line direction. The valve actuating member 134 is supported by the rotor so as to be capable of making a translational movement of the valve actuating member in the axial direction with respect to the rotor 172, while a rotational movement with respect to the rotor 172 is regulated.