Patent Application
20050178992
The present invention relates to solenoid valves.
Solenoid valves have many industrial applications. As one non-limiting example, vehicles can have numerous vehicle subsystems that are designed to increase the comfort and safety of drivers and passengers, such as anti-lock braking systems, traction control systems, speed control systems, vehicle stability enhancement control systems, and so on, and each subsystem can include numerous electromagnetic sensors and solenoid valves.
Typically, such valves include a rod attached to a plunger, with both rod and plunger reciprocating under the influence of electromagnetic force when a coil surrounding the plunger is energized and deenergized. More specifically, when the coil is energized the rod moves against a ball to push the ball away from a valve seat and thereby permit fluid flow through the seat. On the other hand, when the coil is deenergized the rod moves back to allow the ball (under the influence of fluid pressure) to move back against the seat, closing off fluid flow through the seat. To minimize rod wear against the ball, in the deenergized configuration the rod is positioned against or very close to (e.g., distanced very much less than 0.1 mm from) the ball.
As recognized herein, however, when the solenoid is energized and the rod starts its motion against the ball from a position in which it is in contact with the ball or very much less than 0.1 mm away from the ball, it builds up little or no momentum before it must push the ball away from the seat against the force of fluid pressure. This in turn translates to a relatively slow turn-on response time, a drawback in many systems that require relatively quick valve actuation times. The present invention, in addressing this problem, notes further that it is desirable to provide a solenoid valve with relatively fast turn-on response times without imposing unduly tight manufacturing tolerances.
A solenoid valve includes a valve housing supporting a coil. A ball is in the valve housing for selectively blocking a valve seat in the valve housing. A rod is reciprocatingly disposed in the valve housing between a deenergized configuration, wherein the coil is deenergized, the ball is against the valve seat, and the rod is distanced from the ball by between one tenth and eight-tenths of a millimeter (0.1 mm-0.8 mm) inclusive, and an energized configuration, wherein the coil is energized and the rod is urged against the ball to move the ball away from the valve seat.
In a preferred embodiment the valve housing defines the valve seat and is made integrally with a winding bay, with the coil being wound in the winding bay.
The preferred rod may include a shaft and a pin engaged with the shaft and contacting the ball when the rod is in the energized configuration. The pin may be made of a material that is harder than the shaft. The pin may be made of a ferromagnetic material and the shaft is made of a non-ferromagnetic material.
A plunger can be staked to a portion of the rod that is formed with grooves, to limit unwanted motion between the rod and plunger during staking. Also, the preferred rod can be formed with first and second guiding surfaces between the pin and plunger that define a first diameter, with the rod being further formed with a stepped region intermediate the first and second guiding surfaces and defining a second diameter smaller than the first diameter.
If desired, the valve housing may be formed with at least one ball retainer rib defining a supply port having a first diameter. The ball is disposed between the rib and valve seat and has a diameter larger than the first diameter such that the rib retains the ball from passing outward through the supply port.
In one non-limiting embodiment, the valve housing is formed with a supply port, a control port, and an exhaust port. Fluid communication is blocked through the supply port and established through the exhaust and control ports in the deenergized configuration. On the other hand, fluid communication is blocked through the exhaust port and is established through the supply and control ports in the energized configuration. The valve may be part of a vehicle fluid system.
In another aspect, a solenoid valve for a vehicle includes a housing holding a rod, a ball, and a valve seat therebetween. The rod is disposed in the valve housing when in a deenergized configuration to permit the rod, when moving toward an energized configuration, to pre-travel a distance before contacting the ball that is sufficient to reduce a turn-on response time of the valve compared to a turn-on response time when the rod contacts or is very near to the ball in the deenergized configuration.
In yet another aspect, a valve for a vehicle includes a housing forming a valve seat, and seat blocking means in the valve housing and movable toward and away from the valve seat for selectively blocking the valve seat. Actuation means are in the valve housing for moving the valve seat blocking means. Energization means are also in the valve housing and are controllable to move the actuation means against the valve seat blocking means. The actuation means is configured and disposed such that it builds up substantial momentum under the influence of the energization means when moving toward the valve seat blocking means, prior to contacting the valve seat blocking means.
The details of the present invention, both as to its structure and operation, can best be understood in reference to the accompanying drawings, in which like reference numerals refer to like parts, and in which:
Referring initially to
With the above disclosure in mind, it may now be appreciated that in the preferred embodiment, the valve housing 18 is not a separate component from the winding bay 20, but instead both are made integrally together, eliminating the need to assemble two separate components. To make the combination of structure shown in
To move the ball 42 away from the valve seat 40, the preferred non-limiting rod 32, most of which defines a shaft made of non-ferromagnetic material, includes a preferably ferromagnetic or otherwise hardened pin 52 that can be press fit into the enlarged secondary valve element 48 of the rod 32 to contact the ball 42 when in the energized configuration as more fully disclosed below. Thus, the preferred rod 32 is a two-piece rod, with most of the rod being non-ferromagnetic and with the portion of the rod (i.e., the pin 52) that must repeatedly contact the ball 42 being hardened compared to the remainder of the rod, for better wear.
With the above structural disclosure in mind, it may now be understood that the rod 32 is reciprocatingly disposed in the valve housing 18 between the deenergized configuration shown and an energized configuration. In the deenergized configuration, the coil 22 is deenergized, the ball 42 is forced by fluid pressure against the valve seat 40 to block fluid flow from the supply port 44 to the control port 46, and the secondary valve element 48 of the rod 32 is distanced from the exhaust port 50 by fluid pressure to allow fluid communication from the control port 46 through the exhaust port 50. In contrast, in the energized configuration, the coil 22 is energized to move the plunger 36 (and, hence, rod 32) to the right in
In accordance with the present invention and as best shown in
While the particular SOLENOID VALVE as herein shown and described in detail is fully capable of attaining the above-described objects of the invention, it is to be understood that it is the presently preferred embodiment of the present invention and thus, is representative of the subject matter which is broadly contemplated by the present invention, that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural and functional equivalents to the elements of the above-described preferred embodiment that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it is to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. section 112, sixth paragraph, unless the element is expressly recited using the phrase “means for.”
