Land vehicles – Wheeled – Attachment
Reexamination Certificate
2000-05-25
2001-05-15
Mai, Lanna (Department: 3619)
Land vehicles
Wheeled
Attachment
C280S737000, C280S742000
Reexamination Certificate
active
06231077
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to valve assemblies, and more particularly, to a dynamic control valve system adapted for inflatable restraint systems for vehicles.
Currently, there is a need for improved operating characteristics for air bags as safety restraints for occupants of a vehicle for reducing the possibility of injury to such occupants during a crash. Typical air bag systems include an inflatable air bag, a source of pressurized gas, and a control mechanism. The control mechanism couples the air bag to the source of pressurized gas to rapidly inflate the air bag with the pressurized gas if the vehicle is subjected to a high rate of acceleration or deceleration, as may be caused by a crash, for example.
Most known air bag systems provide substantially instantaneous application of high pressure gas to the air bag, resulting in the air bag being inflated at a very high rate and producing large forces. Such speed and force are required in order to restrain a person of average size or larger. However, the high speed with which the air bag opens and the large force with which the expanding air bag contacts the occupant of the vehicle as the air bag is inflated may injure occupants, who are, for example, children or smaller adults. Most air bag inflation systems currently on the market are not dynamically controlled to optimally protect the particular occupant.
Many air bag systems use mechanical or pyrotechnic control inflation of systems to the air bag. This is partly attributable to the relatively slow response time of known electronically controlled valves. In some valves, mechanical springs are used to bias the valve to its closed position. The spring bias must be overcome to open the valve. The spring bias increases response time and also increases the required size of the electrical winding, so that more power is required and more heat is generated Many prior art valves are opened with pressure assist to minimize the time needed to completely open the valve. However, this pressure assist restricts the ability to rapidly close or otherwise adjust the position of the valve after opening.
In addition, known air bag inflation control systems are characterized by complex and costly structures. This is particularly true for valves that employ pressure assist or other mechanical assist Pressure assist valves generally require a pilot valve that is operated by a differential pressures created by orificing and which initiates valve operation, by supplying operating pressure to the valve member of the main valve, or by creating a vacuum by which the main valve is caused to operate at a faster rate.
In recent years, attempts have been made to address some of these problems. One method that has been proposed by some air bag manufacturers is to use multiple inflation containers and firing only the number of containers needed for handling the crash event However, this makes the system controls and layout more complicated. Another method that has been proposed is to use a slower inflation rate. While this can be beneficial to children and adults of smaller stature, this arrangement compromises the safety of the adults who are of average or larger size. Another method is to use multiple stage pyrotechnic devices. Most of these systems typically allow only a single change in inflation.
SUMMARY OF THE INVENTION
The present invention provides a dynamic control valve system adapted for inflatable restraint systems for vehicles. The dynamic control valve system includes a container adapted for at least temporarily containing a fluid under high pressure, and a control valve having a valve inlet in fluid communication with the container and a valve outlet in fluid communication with an inlet of the inflatable restraint. The control valve includes a valve member actuatable between at least a first position in which the control valve is substantially closed and a second position in which the control valve is substantially open. The control valve is arranged to communicate the high pressure fluid through the control valve to the inflatable restraint for inflating the inflatable restraint when the valve member is actuated between the first and second positions. The control valve is constructed and arranged so that actuation of the valve member between the first and second positions is substantially independent of forces produced by flow of the high pressure fluid through the valve, and so that the valve member, when unactuated, is maintained in the first position without mechanical bias.
In accordance with the invention, the inflatable restraint dynamic control valve system further includes a controller which is coupled to the control valve for electrically operating the control valve for actuating the valve member between the first and second positions. The control valve is constructed and arranged to be controlled by the controller to allow the flow rate of the high pressure fluid through the control valve from the valve inlet to the valve outlet to be varied dynamically, thereby varying the rate of inflation of the airbag as a function of said at least one of vehicle parameter and occupant parameter.
In one embodiment, the control valve includes a first valve solenoid for moving the valve member toward the first position and a second valve solenoid for moving the valve member toward the second position. In this embodiment, the valve member, when unactuated, is maintained in the first position without mechanical bias. In another embodiment, the control valve includes a bias structure for urging the valve member toward the first position, and a valve solenoid for moving the valve member, against the force of the bias structure, toward the second position.
In one embodiment of the invention, the control valve includes a valve spool and the valve spool defines split flow paths through the control valve. In addition, the flow paths defined by the valve spool are generally normal to the axis of movement of the valve spool of the control valve. The valve cylinder cooperates with the valve spool to define at least one cross-flow path through the control valve with a major portion of the cross-flow path extending generally normal to the longitudinal axis of the valve cylinder. With this arrangement, the movement of the valve spool between the first and second positions is substantially independent of the high pressure fluid supplied to the control valve as the inflatable restraint inflates. Moreover, when the control valve is operated, one or more leakage paths are provided through the control valve, in parallel with the cross-flow paths.
In addition, the control valve preferably includes an outlet member defining apertures arranged for directing the high pressure fluid introduced into the inflatable restraint along at least one flow path that extends substantially normal to an axis of an inlet of the inflatable restraint. Consequently, there is no direct path into the inflatable restraint at the output of the valve, but rather the output portion of the flow path bends causing the pressurized fluid to be delivered from the valve through outlet ports which have their axes oriented substantially normal to the inlet to the inflatable restraint. Thus, the pressurized fluid is introduced into the inflatable restraint circumferentially and the outlet ports can be disposed diametrically opposed to balance forces and thereby cancel forces generated by the pressurized fluid on the valve. In accordance with a further embodiment, the control valve provided by the invention includes a first valve inlet area located at one end of the valve casing and a second valve inlet area located at the opposite end of the valve casing. In this embodiment, high pressure fluid is introduced into the control valve at locations generally 180° degrees apart. This arrangement balances the inlet pressure, minimizing the effect on valve operation of the high pressure fluid being introduced into the control valve. The control valve further includes a first and second valve outlet areas located at opposite sides
Dahlgren Derek A.
Karolek Neil C.
Sturman Oded E.
Fischer Andrew J.
Mai Lanna
Reinhart, Boerner, Van Deuren, Norris & Rieselbach, s.c.
Sturman/TLX LLC
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