The present invention relates generally to hydraulic flow control devices, and more particularly to poppet-type check valve assemblies for regulating the flow of pressurized fluid through a hydraulic control unit.
Conventional motorized vehicles, such as the modern day automobile, include a powertrain that is comprised of an internal combustion engine (ICE) in power flow communication with a final drive system (e.g., rear differential and wheels) via a multi-speed power transmission. Hybrid type powertrains generally employ an ICE and one or more motor/generator units that operate individually or in concert to propel the vehicle. That is, power output from the engine and motor/generators are transferred through planetary gearing in the multi-speed transmission to be transmitted to the vehicle's final drive. The primary function of the multi-speed power transmission is to regulate speed and torque to meet operator demands for vehicle speed and acceleration.
Most automatic transmissions include a number of gear elements, such as epicyclic planetary gear sets, for coupling the transmission's input and output shafts. One or more hydraulically actuated torque establishing devices, such as clutches and brakes (the term “torque transmitting device” often used to refer to both clutches and brakes) are selectively engageable to activate the above mentioned gear elements for establishing desired forward and reverse speed ratios between the input and output shafts. Engine torque and speed are converted by the transmission, for example, in response to the tractive-power demand of the motor vehicle.
Shifting from one forward speed ratio to another is performed in response to engine throttle and vehicle speed, and generally involves releasing one or more “off-going” clutches associated with the current or attained speed ratio, and applying one or more “on-coming” clutches associated with the desired or commanded speed ratio. To perform a “downshift”, a shift is made from a low speed ratio to a high speed ratio. That is, the downshift is accomplished by disengaging a clutch associated with the lower speed ratio, and engaging a clutch associated with the higher speed ratio, to thereby reconfigure the gear set(s) to operate at the higher speed ratio. Shifts performed in the above manner are termed clutch-to-clutch shifts, and require precise timing in order to achieve high quality shifting.
To engage clutches properly, most power transmissions require a supply of pressurized fluid, such as conventional transmission oil. The pressurized fluid may also be used for such functions as cooling and lubrication. The lubricating and cooling capabilities of transmission oil systems greatly impact the reliability and durability of the transmission. Additionally, multi-speed power transmissions require pressurized fluid for controlled engagement and disengagement, on a desired schedule, of the various torque transmitting mechanisms that operate to establish the speed ratios within the internal gear arrangement.
The various hydraulic subsystems of an automatic transmission, such as the abovementioned torque transmitting devices, are typically controlled through operation of a hydraulic circuit, often referred to as a hydraulic valve system or hydraulic control module. The hydraulic control module traditionally engages (actuates) or disengages (deactivates) the various transmission subsystems through the manipulation of hydraulic pressure generated by one or more oil pump assemblies. The valves used in a conventional hydraulic control circuit commonly comprise, for example, electro-hydraulic devices (e.g., solenoids), spring-biased accumulators, spring-biased spool valves, ball check valves, and poppet check valves.
Check valve assemblies, such as ball- and poppet-type check valves, are often designed to permit fluid to flow in one direction, and restrict fluid flow in the opposite direction. Check valves are characterized by a movable fluid control element (e.g., the poppet or check ball) that is used to close (seal) and open (unseal) one or more valve ports. A biasing member, such as a compression spring, operates to urge the fluid control element off its seat allowing a flow path (e.g., in the case of a 2-way, normally open valve), or closing off a flow path by pushing the fluid control element onto a seat (e.g., in the case of a 2-way normally closed valve). In regard to the latter, the spring acts to bias the fluid control element against the valve seat until the upstream fluid pressure acting against the fluid control element exceeds the spring force of the biasing member, unseating the fluid control element to allow fluid flow above a predetermined fluid pressure.
According to one embodiment of the present invention, a check valve assembly for regulating the flow of pressurized fluid in a hydraulic circuit is provided. The check valve assembly includes a valve housing that defines a valve chamber therethrough. The valve chamber has first and second spaced openings, and a longitudinal center axis. The check valve assembly also includes a fluid control element arranged substantially inside the valve chamber to transition between a seated position, in which the fluid control element fluidly seals one of the valve chamber openings, and an unseated position, in which the fluid control element allows fluid to pass through the now unsealed opening. The check valve also includes first and second guide elements respectively disposed at opposing ends thereof. The guide elements cooperate to maintain the fluid control element in coaxial alignment with the longitudinal center axis of the valve chamber during transitions between the seated and unseated positions.
According to one aspect of this embodiment, the first guide element includes a plurality of fin members that extend between and engage the fluid control element and the inner surface of the valve chamber to thereby radially align a first end of the fluid control element with the longitudinal center axis of the valve chamber. Ideally, the valve chamber includes an inlet portion connected to an outlet portion by a seat portion. In this instance, each of the fin members has a forward edge with a first angle relative to the longitudinal center axis of the valve chamber, whereas the seat portion has a second angle relative to the longitudinal center axis that is greater than the first angle.
In accordance with another aspect of this embodiment, the second guide element includes a disk member with a receiving slot that is configured to receive and thereby radially align a second end of the fluid control element with the longitudinal center axis of the valve chamber. It is also desired that the fluid control element includes a stop oriented between first and second ends thereof. The stop is configured to bottom out against the disk member at a predetermined forward fluid flow rate. In addition, the disk member preferably defines a plurality of apertures therethrough that are collectively configured to allow a predetermined cross-sectional area of fluid flow to pass therethrough.
According to yet another aspect of this embodiment, the check valve assembly also includes an elastomeric ring that is attached to either the valve housing or the fluid control element. The elastomeric ring is configured to engage the other of the valve housing and fluid control element when the fluid control element is in the seated position. Ideally, the fluid control element is configured to bottom out against the valve housing at a predetermined reverse pressure and thereby reduce pressure on the elastomeric ring when the fluid control element is in the seated position. In addition, the fluid control element preferably includes a conical portion that extends from one end thereof. The conical portion is connected to a landing portion by a reduced diameter stepped region. In this instance, the elastomeric ring extends continuously about the stepped region.
As part of yet another aspect of this particular embodiment, a biasing member is in operative communication with the fluid control element, and configured to bias the same into either the seated or unseated positions.
In accordance with another embodiment of this invention, a check valve assembly is provided for regulating the flow of pressurized fluid through a hydraulic control circuit. The check valve assembly includes a valve housing with a valve chamber having first and second openings spaced apart along a longitudinal center axis thereof. The check valve assembly also includes a fluid control element having a stem portion with a fluid obstruction element at a first end thereof. The fluid control element is slidably arranged substantially inside the valve chamber to transition between a seated position, in which the fluid obstruction element is positioned against the valve housing to fluidly seal the first opening, and an unseated position, in which the fluid obstruction element is distanced from the valve housing to thereby allow fluid to pass through the first opening.
A plurality of fin members protrudes outward from the first end of the fluid control element, and engage with the inner surface of the valve chamber. A disk member is oriented inside the valve chamber, and defines a receiving slot therethrough that is configured to receive and mate with a second end of the stem portion. The disk member and fin members cooperate to keep the poppet in coaxial alignment with the longitudinal center axis of the valve chamber during transitions between the seated and unseated positions.
According to one aspect of this particular embodiment, the fluid obstruction element includes a substantially cylindrical landing portion with three of the fin members circumferentially spaced equidistant from one another around an outer peripheral surface of the landing portion.
In another aspect, the valve chamber includes substantially cylindrical inlet and outlet portions that are connected by an angled seat portion that extends therebetween. The inlet portion has a first diameter, whereas the outlet portion has a second diameter that is greater than the first diameter. In this particular instance, each of the fin members has a forward edge that is proximal to the seat portion. The forward edge of the fin members have a first angle relative to the longitudinal center axis of the valve chamber, whereas the seat portion has a second angle relative to the longitudinal center axis that is greater than the first angle. Preferably, the fluid control element is configured such that the forward edge of each fin member bottoms out against the seat portion of the valve chamber at a predetermined reverse pressure.
In accordance with a different aspect of this embodiment, the stem portion includes a stepped, stop portion that is oriented between first and second ends thereof. The stop portion is configured to bottom out against the disk member at a predetermined forward fluid flow rate.
According to another aspect, the fluid obstruction element includes a conical portion extending from the first end thereof. The conical portion is connected to a landing portion by a reduced diameter stepped region. The fluid obstruction element also includes an elastomeric ring that extends continuously about the stepped region, between the conical and landing portions. The elastomeric ring is configured to engage the valve housing to thereby effect the fluid seal between the fluid obstruction elements and the valve housing when the fluid control element is in the seated position.
In yet another aspect, the check valve assembly also includes a retainer ring configured to press fit into the second opening of the valve chamber. The retainer ring is adapted to mate with and thereby retain the disk member inside the valve chamber.
According to yet another embodiment of the present invention, a poppet-type check valve assembly for regulating the flow of pressurized fluid in a hydraulic control circuit is described. The poppet check valve assembly includes a valve housing that defines a generally cylindrical valve chamber therethrough. The valve chamber has opposing inlet and outlet ports that are coaxially arranged and distanced from each other along a longitudinal center axis of the valve chamber.
The poppet check valve assembly also includes a poppet having a stem portion with a fluid obstruction element positioned at a first end thereof. The poppet is slidably arranged inside the valve chamber to transition linearly along the center axis of the valve chamber between a seated position, in which the fluid obstruction element is pressed against a seat portion of the valve housing to fluidly seal the inlet port, and an unseated position, in which the obstruction element is distanced from the seat portion thereby allowing fluid to pass from the inlet port to the outlet port. A spring member is in operative communication with the poppet to bias the same into the seated position.
The obstruction element includes a plurality of circumferentially oriented fin members protruding outward therefrom to engage with the inner surface of the valve chamber. A disk member that defines a receiving slot configured to receive and mate with a second end of the stem portion is oriented inside of the valve chamber. The disk member and the plurality of fin members cooperate to maintain the poppet in coaxial (e.g., radial) alignment with the longitudinal center axis of the valve chamber during the transition between the seated and unseated positions.
The above features and advantages, and other features and advantages of the present invention will be readily apparent from the following detailed description of the preferred embodiments and best modes for carrying out the invention when taken in connection with the accompanying drawings and appended claims.
The present invention is described herein in the context of a motor vehicle powertrain having a multi-speed hybrid-type power transmission, as seen in
Referring to the drawings, wherein like reference numbers refer to like components throughout the several views, there is shown in
The transmission 12 is adapted to manipulate and distribute power from the engine 14 to the final drive system 16. Specifically, engagement of one or more torque transmitting devices (e.g., hydraulically actuated brakes or clutches) included in the transmission 12 interconnects one or more differential epicyclic gear arrangements, preferably in the nature of interconnected planetary gear sets (none of which are visible in
An oil pan or sump volume 28 (also referred to herein as “hydraulic fluid reservoir”) is located on the base of the main housing 13, and is configured to stow or store hydraulic fluid, such as transmission oil (shown hidden in
An exploded perspective-view illustration of a poppet-type check valve assembly in accordance with a preferred embodiment of the present invention is shown generally at 40 in
Looking at both
The first and second outer free ends 50 and 52, respectively, of the valve body 42 are provided with suitable connecting means, such as compression couplings or helical threads (not shown), which allow the valve assembly 40 to be coupled to fluid inlet and outlet lines (not shown). First and second elastomeric o-rings 60 and 62, respectively, are operatively oriented along and mated with the valve body 42, relative to the first and second free ends 50, 52, to provide a fluid-tight seal between the check valve assembly 40 and the fluid inlet and outlet lines.
The valve chamber 44 may be divided into three primary portions—a substantially cylindrical inlet portion 54 that is connected to a substantially cylindrical outlet portion 56 by an angled, annular seat portion 58. The inlet portion 54 has a first diameter D1, and the outlet portion 56 has a second diameter D2 that is greater than the inlet portion diameter D1. A cylindrical end portion 57 is formed downstream of the outlet portion 56. The end portion 57 has a third diameter D3 that is greater than both the first and second diameters D1, D2. It should be recognized that the geometric configurations of the individual portions of the valve chamber 44 may be individually or collectively modified without departing from the intended scope of the present invention.
The poppet check valve assembly 40 also includes a fluid control element, such as poppet 64, which has a stem portion 66 with a fluid obstruction element 68 protruding from a first end 65 thereof. The obstruction element 68, as depicted in
The poppet 64 is operatively arranged inside the valve chamber 44 to translate back-and-forth along the center axis C, such movement represented in
A biasing member, such as a coil spring 78, is in operative communication with the poppet 64, and configured to bias the same into the seated position 64A. That is, a first end 77 of the coil spring 78 presses against a plurality of integrally formed fin members that protrude outward from the landing portion 74 of the poppet 64, as seen in
In accordance with the present invention, the check valve assembly 40 includes first and second guide elements that are engineered to maintain the poppet 64 in coaxial alignment (e.g., radially aligned) with the longitudinal center axis C during the transition between the seated and unseated positions 64A, 64B. Specifically, as noted above, the obstruction element 68 includes a plurality of fin members, namely first, second and third fin members 82, 84 and 86, respectively (82 and 84 visible in
As noted above, a second guide element 80 (also referred to herein as “disk member”) with a receiving slot 88 (
With continuing reference to
The disk member 80 includes a plurality of fluid apertures, such as first, second and third apertures 96, 97 and 98, respectively (best seen in
The poppet 64 is also configured such that the fin members 82, 84, 86 bottom out with metal-to-metal contact against the seat portion 58 at a predetermined reverse pressure to prevent damage to the elastomeric ring member 76. That is, each of the fin members 82, 84, 86 has a forward edge (represented collectively in
While the best modes for carrying out the present invention have been described in detail herein, those familiar with the art to which this invention pertains will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.
This application claims the benefit of and priority to U.S. Provisional Patent Application No. 61/053,864, filed on May 16, 2008, which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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61053864 | May 2008 | US |