subject: Three port solenoid valve [print this page] A solenoid valve includes a housing that establishes a supply port, a control port, and an exhaust port. A fluted bushing is statically affixed within the housing and a poppet slides within the bushing.
The poppet is movable between a de-energized configuration wherein flow is prohibited between the control port and the exhaust port, and permitted between the control port and the supply port, plural partially energized configurations wherein flow is permitted between the supply port and the control port, between the control port and the exhaust port, and between the exhaust port and the supply port, and a fully energized configuration wherein flow is prohibited between the control port and the supply port and flow is permitted between the control port and the exhaust port.
A typical automobile includes numerous systems that use one or more solenoid valves to control the flow of fluid within the system and to control the flow of fluid to and from the system. Many of these solenoid valves are three port solenoid valves that require hydraulic fluid to be isolated or modulated between a supply, control, and exhaust port. In order to properly isolate or modulate the flow of the hydraulic fluid, the geometry around a supply-to-control (S/C) valve seat and the geometry around a control-to-exhaust (C/E) valve seat must be customized as a function of the poppet travel. In most cases, especially linear pressure control solenoid valves, poppet alignment and/or the presence of a spring in the hydraulic flow path can result in significant variation in the functional performance of the solenoid valve.
A typical three port solenoid valve uses a rod and ball configuration to control the flow of fluid between the ports. The rod can have an area that interfaces with one seat and a portion that extends to push a ball away from a second seat. Moreover, the ball has a spring behind it that helps keep it seated or in contact with the rod. This type of configuration produces two annular orifices with a radially floating ball that is sensitive to component alignment. Since the spring is typically within the flow path, it can significantly restrict the flow of hydraulic fluid within the solenoid valve.
The present invention has recognized these prior art drawbacks, and has provided the below-disclosed solutions to one or more of the prior art deficiencies.
A solenoid valve includes a housing in which a preferably "I"-shaped bushing is statically disposed. A flute is formed by the bushing and the flute establishes a fluid flow path through the solenoid valve and connects the control and exhaust ports. Moreover, a poppet is slidably disposed within the bushing.
In a preferred embodiment, the poppet includes an enlarged base that has an outer diameter that is slightly smaller than an inner diameter of the bushing. Preferably, the poppet also includes a proximal end that extends from the enlarged base. A first poppet rod extends from the proximal end and a second poppet rod extends from the enlarged base opposite the proximal end. Further, a distal end is established by the second poppet rod opposite the proximal end.
Preferably, a coil spring is disposed within the bushing around the second poppet rod formed by the poppet. In a preferred embodiment, the housing forms a supply port, a control port, and an exhaust port. The poppet is movable between a de-energized configuration, a partially energized configuration, and a fully energized configuration. In the de-energized configuration, flow is prohibited between the control port and the exhaust port, and permitted between the control port and the supply port. In the partially energized configuration, flow is permitted between the supply port and the control port, between the control port and the exhaust port, and between the exhaust port and the supply port. Moreover, in a fully energized configuration flow is prohibited between the control port and the supply port and flow is permitted between the control port and the exhaust port.
In another aspect of the present invention, a solenoid valve includes a housing that establishes a supply port, a control port, and an exhaust port. In this aspect, a bushing is statically disposed within the housing and a poppet is slidably disposed within the bushing. The poppet is movable between a de-energized configuration, a partially energized configuration, and a fully energized configuration. In the de-energized configuration, flow is prohibited between the control port and the exhaust port, and is permitted between the control port and the supply port. In the partially energized configuration, flow is permitted between the supply port and the control port, between the control port and the exhaust port, and between the exhaust port and the supply port. Additionally, in the fully energized configuration, flow is prohibited between the control port and the supply port and flow is permitted between the control port and the exhaust port.
In yet another aspect of the present invention, a fluid control system includes a fluid supply, a hydraulically controlled device, a fluid exhaust, and a solenoid valve that is in fluid communication with the fluid supply, the hydraulically controlled device, and the fluid exhaust. In this aspect, the solenoid valve includes a bushing that is statically disposed therein and a poppet that is slidably disposed within the bushing.
