This application relates generally to lift axles on heavy or commercial freight vehicles.
Some heavy or commercial freight vehicles include an auxiliary lift axle that may be deployed, such as when the weight of the vehicle exceeds a roadway limit on per-axle weight for the vehicle. Some lift axles may be pneumatically activated.
There exists a need for a pneumatic control system for deployment of a lift axle.
A pneumatic lift axle control system may comprise a plurality of valves configured to receive first fluid pressure from a first fluid supply and to receive second fluid pressure from a second fluid supply, and to selectively communicate the first fluid pressure or the second fluid pressure as a pilot signal to a lift axle actuator valve.
The pneumatic lift axle control system may include a command valve system configured to receive first fluid pressure from a first fluid supply and to receive second fluid pressure from a second fluid supply. The command valve system may be configured to selectively communicate the first fluid pressure and the second fluid pressure to a pilot valve system. The pilot valve system may be configured to receive the first fluid pressure and the second fluid pressure from the command valve system, and to selectively communicate the first fluid pressure or the second fluid pressure as a pilot signal to the lift axle actuator valve.
A heavy vehicle may include a lift axle that moves up when the vehicle is unloaded and may be moved down when the vehicle is loaded. That is, when the vehicle is not loaded, road travel resistance decreases by moving up the lift axle so that the lift axle tires are off of the road. When the vehicle is loaded, the load may be supported by the lift axle tires by moving the lift axle down into a deployed position.
A lift axle may be disposed in front of a down or fixed axle on a heavy truck or trailer. A lift axle in such a position is commonly referred to as a pusher axle. A lift axle may also be disposed behind a down axle on a heavy truck or trailer. A lift axle in such a position is commonly referred to as a tag axle. Lift axles may be steerable or non-steerable.
A pneumatic lift axle suspension system typically includes a pneumatic lift spring to move the lift axle up and down, and a pneumatic ride spring to absorb vibration from a road surface when the lift axle moves down into a deployed position. Depending on lift axle configuration, inflation of a lift spring may move a lift axle to an up or raised position or to a down or deployed position.
Referring to
In the embodiment of
The ride spring 22 is disposed between the lift axle 16 and the vehicle body (not shown) to absorb vibration from a road surface when the lift axle 16 is deployed. The lift spring 20 and the ride spring 22 are each connected to a fluid supply (e.g., air) (not shown) through fluid pressure supply hoses (not shown). Air pressure in the lift springs 20 and ride springs 22 is controlled through an actuator valve. Accordingly, the lift spring 20 controls the up/down operations of the lift axle 16 through a lift axle deployment system, and the ride spring 22 absorbs vibration from the road surface as the tires of the lift axle 16 travel on the road. The lift axle deployment system comprises a lift axle control system and an actuator valve.
The actuator valve is configured to switch between an OFF state and an ON state. When the pilot 56 is not activated, as seen in
When the pilot 56 is activated as shown in
The actuator valve 50 thus has two states: a pilot-activated state which results in the lift axle being raised, and a pilot-inactive state in which the lift axle is deployed.
A heavy vehicle having a lift axle includes a ride fluid supply and a lift fluid supply, which may be the same or separate reservoirs or fluid supply sources. The lift air supply may provide air at a pressure suitable to inflate the lift spring and raise the lift axle. The ride air supply may provide air at one or more pressures suitable for the vehicle suspension at one or more vehicle load states.
A heavy vehicle also typically includes a parking brake air brake system. In the disclosed embodiment, the disclosed lift axle system relies on the parking brake air system, which typically includes a brake air reservoir and a brake air supply as is known in the art. The brake air supply fills the brake air reservoir so that the parking brake system has a volume of air available for rapid use. Generally speaking, when the parking brake is engaged there is a low pressure in the brake supply line. A low pressure may range from zero pressure up to the operating pressure needed to disengage the parking brake, such as 40 psi.
When the vehicle is turned on and in drive mode, the parking brake air system may be activated to provide air pressure to disengage the parking brakes. That is, the air brake supply line may be pressurized with air, which fills the brake air reservoir and disengages the park brakes by caging a large return spring. In the disclosed embodiment, the brake system air pressure is used to keep the lift axle up while the vehicle is in motion (except for heavy load override as described below). This prevents the axle from dropping while the vehicle is in motion. While caging of the return spring in the parking brake is described, such description is exemplary only and not meant to preclude other parking brake configurations. Regardless of parking brake configuration, the pressure in the brake systems may be used to indicate the status of the parking brake system as engaged or disengaged.
Vehicle drivers typically stop completely before applying the parking brakes. When the park brakes are applied, the air brake supply line pressure drops to a low-pressure state and the lift axle can then be deployed to a lowered position.
As seen in
As may be seen in the embodiment of
The command valve system 152 may itself comprise of one or more valves V1 and V2 for allowing pressurized fluid to flow to valves V3 and V4 of the pilot valve system 154. A command valve system 152 may further comprise pressure sensors, a housing, an electronic control unit, and other electronic control devices. The command valve system 152 may further comprise any other control circuitry and electronics as needed to capture, interpret, and send signals to and from sensors, valves, status lamps and other electronically controlled devices in or communicating with the lift axle control system. Such electronics and circuitry may be powered by a vehicle power supply through an electrical bus connector 156.
The pilot valve system 154 may include valves V3 and V4 that control the flow of fluid through the lift axle control system 150. These valves may be in a housing or body either with or separately from the command valve system 152.
The command valve system 152 may comprise a trigger valve V2 and an override valve V1. The trigger valve is a two-position solenoid valve having ports TV1, TV2 and TV3. In the OFF state of the trigger valve V2 (as shown), port TV1 is connected to an external air supply 158, typically the air brake reservoir, and to no other port of the trigger valve V1. Port TV2 is connected to the port TV3 which is in turn connected to an exhaust or vent port. The trigger valve may receive a trigger signal from an electronic control unit 166. The trigger signal causes the trigger valve V2 to switch states.
The override valve V1 is a two-position solenoid valve having ports OV1, OV2 and OV3. In the OFF state for override valve V1 (as shown), port OV1 is connected to a vent port and to no other port in the override valve V2. Ports OV2 and OV3 are connected so as to allow air flow through the override valve V1 from an air brake supply line 160 to the valve V3 of the pilot valve system 154. The override valve V1 may receive an override signal from an electronic control unit 166. The override V1 signal causes the override valve V1 to switch states.
The command valve system 152 may be coupled to or made part of an electronic control unit (ECU) 166 that further includes a ride spring air pressure sensor 162 RS and a brake supply pressure sensor 164 PS. The ECU 166 may receive ride spring pressure data from the ride spring air pressure sensor 162 RS and calculate vehicle load data based on the ride spring pressure data. The vehicle load data may be used to trigger the override valve V1 or trigger valve V2 to an ON state. Thus, the lift axle control system 150 can automatically set the lift axle position based upon the amount of load on the vehicle.
The loads may be categorized for use in determining deployment state. For example, a vehicle load falling into a Level One category may represent tare weight or a minimal cargo load, and the lift axle control system 150 may ensure that the lift axle is in the raised position unless the system or driver chooses to deploy the lift axle. A vehicle load weight falling into a Level Two category may represent a minimum threshold weight for lowering or deploying the lift axle. A Level Three category load weight may represent a maximum threshold weight at which the lift axle must deploy no matter the disposition of any other deployment criteria. In some embodiments, the vehicle operator may have the ability to override the system and deploy the lift axle. In other embodiments, the ability of the vehicle operator to manually control or override the deployment of the lift axle may be limited by the ECU and only available in limited situations such as emergencies or maintenance operations. In yet other embodiments, such as in highly-regulated driving environments, there may be no method for the vehicle operator to override or manually control axle deployment.
In the disclosed embodiment, the ride spring pressure sensor 162 RS sends an RS load signal to the ECU 166 so that the ECU 166 can monitor the weight of the vehicle load. The ECU 166 calculates the weight of the cargo load based on the RS load signal to determine whether the lift axle should be deployed. For a vehicle containing an air suspension, the ride spring pressure sensor 162 RS may monitor the increases and decreases in pressure of the suspension system and thus determine the weight of the cargo load. Alternately, a ride spring pressure sensor 162 RS may measure the level of deflection created by a cargo load as referenced from the vehicle position at tare weight only. Other sensor modalities for measuring weight may also be utilized in place of, or in combination with, the above-mentioned ride spring pressure sensor modalities.
As discussed, the lift axle may only be raised and lowered under certain conditions. For example, for safety reasons, the axle may not lower with a Level Two load weight and the vehicle in drive mode. Also, the axle may not lower when the vehicle carries a Level One load and the vehicle is in drive mode. The axle may be lowered with a Level Three load independent of the whether the vehicle is in drive or park mode. In some embodiments, the axle may be able to be raised when the vehicle is in motion, regardless of the weight of the load and may automatically lower when the vehicle is in park mode. In other embodiments, the axle will not lower from the raised position when there is no electrical power being supplied from a vehicle power supply to the lift axle control system 150, thus the axle will not accidentally lower in the event of vehicle power loss while the vehicle is in drive mode. Axle position as a function of load weight and vehicle state may be seen in the vehicle condition list embodiment of Table 1.
Lift axle position may be determined based on vehicle load level, whether the vehicle ignition is on or off, and the vehicle drive or park state. As may be seen from Table 1, at any load level, when the vehicle is in park and turned off, the lift axle will stay down if it was in the down position when the vehicle was placed in park and turned off (condition 1), and will drop down if it was in the up position when the vehicle was placed in park and turned off (condition 2).
At load level 1, when the vehicle power is off but is still in drive mode (such as may happen if the vehicle loses power while being driven), the lift axle will remain in the up position (condition 6). If the vehicle power is on but the vehicle is in park mode, the axle will move to the raised position (condition 3). When the vehicle is placed in drive mode, the axle will stay in the up position while at load level 1 (condition 4) unless the ECU otherwise determines that the lift axle is to be deployed (condition 5). In some embodiments, in condition 5, the operator may be provided the ability to override the system and deploy the lift axle. In other embodiments, the ability of the operator to manually control or override the deployment of the lift axle may be limited by the ECU and only available in limited situations such as emergencies or maintenance operations. In yet other embodiments, there may be no method for the operator to override or manually control axle deployment.
At load level 2, when the vehicle power is on and the vehicle is in drive mode, the lift axle may be raised (condition 7) or deployed (condition 8) by the system. However, if the vehicle power is off but is still in drive mode, the lift axle will move to or remain in the up position (condition 9). When the vehicle is placed in park and turned off, the lift axle will drop if in an up position (condition 10). In some embodiments in condition 8, the operator may be provided the ability to override the system and deploy the lift axle. In other embodiments, the ability of the operator to manually control or override the deployment of the lift axle may be limited by the ECU and only available in limited situations such as emergencies or maintenance operations. In yet other embodiments, there may be no method for the operator to override or manually control axle deployment.
At load level 3, when the vehicle power is on, then the lift axle will deploy (condition 11) or remain deployed (condition 12) if the vehicle is in drive or park mode. If the vehicle power is off, then the lift axle will remain deployed (condition 13) in drive or park mode. However, if the lift axle is in the up position at load level 3 and the vehicle is in drive mode but the power is off, then the lift axle will stay in the up position (condition 14). In some embodiments in condition 14, the operator may be provided the ability to override the system and deploy the lift axle. In other embodiments, the ability of the operator to manually control or override the deployment of the lift axle may be limited by the ECU and only available in limited situations such as emergencies or maintenance operations. In yet other embodiments, there may be no method for the operator to override or manually control axle deployment.
With reference again to
The pilot valve system 154 comprises a latching valve V3 and a shuttle valve V4. The latching valve V3 includes a latch shuttle 170 configured to move between a first shuttle position and a second shuttle position, and includes latch ports LV1, LV2, LV3, and LV4. Port LV4 vents to atmosphere and serves to maintain a generally constant pressure in the end cap of the latching valve as the latch shuttle 170 translates between positions. Port LV4 may be sealed by a gland 161, such as an o-ring, disposed so as to prevent contaminants from entering port LV4 from the outside environment, but release pressure buildup from the latching valve V3. In the embodiment of
The shuttle valve V4 includes a shuttle 172 configured to move between a first shuttle position and a second shuttle position, and includes ports SV1, SV2, SV3 and SV4. In the embodiment of
The latching valve V3 and shuttle valve V4 may be separately provided or may be provided in unitary body as shown in the embodiment of
The trigger valve V2 controls the flow of pressurized air from the brake air reservoir to the shuttle valve V4, and from the shuttle valve V4 to atmosphere via an exhaust vent connected to port TV3. Port TV1 is connected to the brake air reservoir. Port TV2 is connected to port SV1 of the shuttle valve. Port TV3 is connected to the exhaust vent. In some embodiments, port TV1 may be connected to sources of pressurized fluid other than the brake air reservoir, such as a pressure tank of an onboard air compressor.
Override valve V1 controls the flow of pressurized air from the brake air supply 160 to the latching valve V3, and from the latching valve V3 to atmosphere via exhaust vent. Port OV1 is connected to the exhaust vent. Port OV2 is connected to port LV1 of the latching valve V3. Port OV3 is connected to the brake air supply 160.
As seen in the embodiment of
The lift axle control system is configured to lower the lift axle to a deployed position such that the tires of said axle are in contact with the travel surface. Generally, the lift axle is lowered when the vehicle is turned off and is in park mode, or when the vehicle load exceeds a threshold weight. The lift axle control system is generally configured to raise the lift axle and maintain the lift axle in a raised state when the vehicle is in drive mode, even if the ECU loses power, except in overweight conditions in which load weight requires that the axle be in the lowered position. The system may also raise the axle when in park mode with a light load if the vehicle ignition is on. Of course, the deployment mode may be overridden or restricted as described above.
As seen in
If the ECU determines that upon turning on the vehicle ignition there is a heavy load condition, then the command valves V1 and V2 would remain in the OFF position (and the light panel 200 would so indicate), as shown in
The trigger valve V2 may be turned on either manually by the vehicle operator, or automatically when the ECU determines that the vehicle load exceeds a weight threshold for deploying the lift axle. In some embodiments, the operator may have the ability to override the system and deploy the lift axle. In other embodiments, the ability of the operator to manually control or override the deployment of the lift axle may be limited by the ECU and only available in limited situations such as emergencies or maintenance operations. In yet other embodiments, there may be no method for the operator to override or manually control axle deployment.
Referring to
As shown in
If the vehicle is carrying a heavy load in drive mode, as in
As seen in FIG.11, in the event of a low power event or complete loss of power when in drive mode, the system will maintain the axle in the raised position by pneumatic pressure when under a light load. The command valves V2 and V1 will be already in the OFF position while in light load drive mode and would require power to transition to another position at which the axle would be able to lower. The indicator light panel will show all of the lights as dark.
As shown in
In
As seen in
While drive mode is engaged, the lift axle may be held in the raised position by purely pneumatic means if power to the ECU is lost or the ignition turns off, as seen in
When the vehicle is turned off and the parking brake is set, then the ECU may reset the lift axle deployment system such that the trigger valve 304 is off, the override valve 302 is off, the shuttle valve 308 is in the first shuttle position and the latching valve 306 is in the first latch position, thus resulting in the lift axle lowering to a deployed position.
The ECU may be programmed with a particular logic or method by which determinations as to axle deployment may be made. The ECU may iterate through a decision tree in which a set of interrogatives are posed, and sensor data is applied to answer said interrogatives. Each interrogative and answer set will result in either a change in axle deployment state or advancement to the next interrogative-answer set. In some embodiments, the decision tree may be a continuously running application. In other embodiments, the execution of the decision tree may be triggered by detection of a change in the monitored data set.
For example, an initial vehicle state may comprise of the axle in the lowered position, the ignition off, and the parking brake engaged. Beginning execution of the decision tree at said state, a first interrogative may be whether the parking brake is engaged (park mode) which would then result in a positive or negative answer return. A negative answer would result in the axle remaining down while a positive return would advance the decision tree to determine if the ignition is on. A negative answer would result in the axle remaining down while a positive return would advance the decision tree to determine if a heavy cargo weight is present. A positive answer would result in the axle remaining down while a negative return would advance the decision tree to determine if a low cargo weight is present. A negative answer would result in the axle remaining down while a positive return would indicate a vehicle state wherein the axle is raised, ignition is on, and the parking brake is engaged.
This second vehicle state would result in iteration through another set of interrogatives. The first interrogative in this set may check if the vehicle is drive mode. A negative answer would result in the axle remaining up while a positive return would advance the decision tree to determine if a heavy cargo load is present. A positive answer would result in the axle being lowered while a negative return would advance the decision tree to determine if the ignition is off. A positive answer would result in the axle being raised while a negative return would advance the decision tree to determine again whether the vehicle is in park mode. A positive answer would advance the decision tree to determine if the ignition state while a negative return would advance the decision tree to the drive mode interrogative.
As seen in the embodiment of logic states or steps 350 shown in
In state 364, the vehicle is in an idle park mode with power on and the axle raised. The vehicle can thus be shut off and powered down (thus returning to state 352), or placed into drive mode and operated to haul a load. Or, the vehicle can remain in park mode. In step 366, if the vehicle is not placed in drive mode, then the lift axle will remain raised (state 368). In some cases, a vehicle may be loaded while in idle park mode. If the vehicle is thereafter placed in drive mode in step 366, then the ECU will once again determine the vehicle load. In step 370, the ECU will check for a vehicle load above the lift axle deployment threshold. The lift axle will remain down (state 372) if the ECU senses a vehicle load above the lift axle deployment threshold. If the ECU does not sense a vehicle load above the lift axle deployment threshold (such as a high or maximum deployment threshold above which the lift axle must be deployed), then the axle will remain up while the vehicle is driven.
In step 374, if the vehicle loses power while being driven with the axle up and the ECU powers down, then the trigger valve and override valve will both be in an OFF state. In the OFF state, the trigger valve will switch to exhaust pressure from the shuttle valve, and the override valve will continue to pass brake air pressure to the latching valve, which will in turn pass pressurized air to the shuttle valve to switch the shuttle valve so as to allow the pressurized air to flow through the shuttle valve to the pilot of the actuator so as to maintain the actuator state in which the lift axle is raised (state 376).
In step 374 if the vehicle does not lose power while being driven with the axle up, then the axle will remain up until the vehicle is stopped or the driver overrides the lift axle control system ECU state to force the lift axle to drop down to a deployed state. If the vehicle stops and is not placed into park mode (step 378), then the ECU will treat the vehicle as still being in drive mode state. If the vehicle is stopped and placed in park mode (step 378), then the ECU will continue to monitor the vehicle load if the ignition remains on (step 358). If the vehicle is stopped, placed in park mode (parking brake engaged) and the ignition turned off, then the parking brake supply will de-pressurize. Thus, the override valve will be in the OFF state but not passing pressurized fluid to the latching valve. The trigger valve will also be OFF, and not passing brake pressure fluid to the shuttle valve. Without pressure to shuttle valve or latching valve, the pilot valve system will not send a pilot signal to the actuator, which will result in the actuator switching to lower the lift axle to a down position (state 356). With the vehicle in park mode with the ignition off and lift axle down, the vehicle returns to state 352.
Shuttle Valve
A shuttle valve for use in a pilot valve system is described in more detail in connection with the embodiment of
The shuttle 404 may translate between a first shuttle position (as seen in
With reference to
The shuttle valve 400 may comprise a discrete valve assembly, or may be formed in a body common with a latching valve.
Latching Valve
A latching valve for use in a pilot valve system is described in more detail in connection with the embodiment of
The latch shuttle 456 comprises a first annular latch seal 466, a second annular latch seal 468 and a third annular latch seal 470, each configured to form a sealing interface between the latch shuttle 456 and the latch shuttle channel 454.
The latching valve 450 may have five ports LV1, LV2, LV3 and LV4 formed therein. Port LV4 provides fluid communication between the interior of the latching valve cap 457 and atmosphere. Port LV4 may be sealed by a gland, such as an o-ring disposed so as to prevent contaminants from entering port LV4 from the outside environment, but release pressure buildup from the latching valve cap 457.
The latch shuttle 456 may translate in the latch channel 454 between a first latch position (as seen in
In the second latch position, the first annular seal 466 and the third annular seal 470 seal the latch shuttle 456 to the latch channel 454. The latch shuttle 456 may translate in the latch channel 454 from the first latch position to the second latch position when fluid pressure is applied at port LV2. If the fluid pressure at port LV2 is sufficient to overcome the biasing force of spring 460 and compress the spring 460, then the latch shuttle 456 will move from the first latch position to the second latch position. In the second latch position, port LV2 remains sealed from port LV1 by the first annular latch seal 466, and ports LV3 and LV4 are sealed from each other by the third annular latch seal 470. Second annular latch seal 468 does not form a sealing interface between the latch shuttle 456 and the latch channel 454, thus allowing fluid to flow through the latching valve 450 between ports LV1 and LV3 via the latch channel.
The latching valve 450 may comprise a discrete valve assembly, or may be formed in a body common with a shuttle valve.
In other embodiments, the latching valve may be configured with an optional or alternative override port LV5. As may be seen in the embodiment of
The latch shuttle 506 comprises a plurality of latch seals, including first annular latch seal 518, a second annular latch seal 520 and a third annular latch seal 522, each configured to form a sealing interface between the latch shuttle 506 and the latch channel 504. The latch shuttle 506 further includes a latch bore 524 extending through the latch shuttle 506 from the end 514 of the latch shuttle 506 to a one-way check valve 526 located in the latch shuttle 506 between the second annular seal 520 and the third annular seal 522. The normally-closed one-way check valve 526 is disposed in the latch bore 524 so as to prevent fluid from flowing from the latch channel 504 into the latch bore 524, but permit fluid to flow from the latch bore 524 into the latch channel 504. In some embodiments, the one-way check valve 526 may be configured to open at a pre-determined cracking pressure.
One end 514 of the latch shuttle 506 may be configured as a piston to slide within the latch valve cap 514. An annular latch seal 530 is disposed between the end 514 and the latch valve cap 508 so as to form a sealing interface therebetween.
The latching valve 500 may have four ports LV1, LV2, LV3 and LV4 formed therein. Port LV4 provides fluid communication between the interior of the latching valve cap 508 and atmosphere. Port LV4 may be sealed by a gland 528, such as an o-ring, disposed so as to prevent contaminants from entering port LV4 from the outside environment, but release pressure buildup from the latching valve cap 508.
The latch shuttle 506 may translate in the latch channel 504 between a first latch position (as in
In the second latch position, the first annular seal 518 and the third annular seal 522 seal the latch shuttle 506 to the latch channel 504. The latch shuttle 506 may translate in the latch channel 504 from the first latch position to the second latch position when fluid pressure is applied at port LV2. If the fluid pressure at port LV2 is sufficient to overcome the biasing force of spring 512 and compress the spring 512, then the latch shuttle 506 will move from the first latch position to the second latch position. In the second latch position, port LV2 remains sealed from port LV1 by the first annular latch seal 518, and ports LV3 and LV4 are sealed from each other by the third annular seal 522. Second annular latch seal 520 does not form a sealing interface between the latch shuttle 506 and the latch channel 504, thus allowing fluid to flow through the latching valve 500 between ports LV1 and LV3 via the latch channel 504, as shown in
As shown in
When the latch shuttle 506 translates back to the first latch position, the first latch seal 518 and the second latch seal 520 seal the latch shuttle 506 to the latch channel 504 as described above. Fluid may flow between ports LV3 and LV4 as described above. Fluid may flow from port LV3 to exhaust port LV4, thus removing a pilot signal from the lift actuator as described above to cause the lift axle to rise.
As seen in
The override port LV5 may be coupled to an air suspension system. An increased vehicle load will increase pressure in an air suspension system, such as may be felt at ride air springs. If the vehicle load increases pressure in an air suspension system, such increased air pressure may be provided at override port LV5. As may be seen in
In yet other embodiments, a normally-closed manually-operable override valve 554 may be provided at port LV5. A manually-operable valve override may have a vent port 556, a pressure line port 558 and a flow port 560. The flow port 560 may be coupled to port LV5 of the latching valve. Pressure line port 558 may be coupled to an air pressure source 564, such as a brake air pressure source or other source of constant fluid pressure. When the manual plunger 562 is in a first plunger position, the flow port 560 is fluidly connected to the vent port 556 so as to vent pressure from port LV5. When the manual plunger is moved to a second plunger position, the flow port 560 is fluidly connected to the pressure line port 558 so as to permit flow from a pressure source 564 to the port LV5 and thus translate the latch shuttle from a second latch position to a first latch position. In some embodiments, the manual plunger may be biased to the first plunger position by a spring (not shown). When the manual plunger is released, the manual plunger returns to the first plunger position.
In some embodiments, both a pressure valve actuator 550 and a manual override valve 554 may be coupled to port LV5 of the latching valve 500.
The lift axle deployment system may also have one or more visual communication devices disposed upon the housing so as to provide readily accessible information as to the status of the system. Indictor lamps, such as provided in an indicator light panel, may be one form of communication device utilized for this purpose. For example, a lamp may flash at the completion of any internal start up checks the system completes. A lamp may also maintain a constant illumination when the axle is in the raised position. Alternately, a constant illumination may be used to communicate that the axle is on the lowered position. A lamp may be utilized to communicate the weight of a load by identifying whether the load falls into the Level One, Level Two, or Level Three category. An indicator lamp may also illuminate to communicate a warning when the deployment status of the axle is imminent so as to prevent injury or damage to the system. The lamp may flash or otherwise illuminate for a period of time prior to the initiation of a change in deployment status and any load change may be required to remain constant during this period or otherwise said transition may not occur so as to prevent damage to the vehicle, axle, transition system, or other related components and systems. A lamp may also flash or otherwise illuminate in preset or user defined codes to communicate a variety of information concerning the system.
The lift axle deployment system may have power supplied through a constant power circuit, such as the blue wire circuit on trailer. The blue wire may supply power for communication components that are included in the deployment system. In addition to visual communication devices, the system may also include communication modules such as wireless communication devices and other components that may be desired to enable configurable variables for the axle deployment system. The deployment system may also have electronic components for the control of solenoids and the monitoring of signals from sensors.
Various embodiments of the lift axle deployment system, components, vehicles thereof, and methods of lift axle deployment are further disclosed in the following numbered clauses.
1. A pneumatic lift axle control system comprising a plurality of valves configured to receive first fluid pressure from a first fluid supply and to receive second fluid pressure from a second fluid supply, and to selectively communicate the first fluid pressure or the second fluid pressure as a pilot signal to a lift axle actuator valve.
2. The pneumatic lift axle control system of clause 1, further comprising a command valve system configured to receive first fluid pressure from a first fluid supply and to receive second fluid pressure from a second fluid supply, the command valve system configured to selectively communicate the first fluid pressure and the second fluid pressure to a pilot valve system; and the pilot valve system configured to receive the first fluid pressure and the second fluid pressure from the command valve system, and to selectively communicate the first fluid pressure or the second fluid pressure as a pilot signal to the lift axle actuator valve.
3. The pneumatic lift axle control system of clause 2, wherein when the pilot valve system communicates neither the first fluid pressure nor the second fluid pressure as a pilot signal to the lift axle actuator valve, the lift axle actuator valve deploys or maintains a lift axle in a lowered position.
4. The pneumatic lift axle control system of clause 3, wherein when the pilot valve system communicates either the first fluid pressure or the second fluid pressure as a pilot signal to the lift axle actuator valve, the lift axle actuator valve deploys or maintains a lift axle in a raised position.
5. The pneumatic lift axle control system of clause 4, wherein the first fluid supply comprises a brake air supply or a brake air reservoir, and the second fluid supply comprises the brake air supply or the brake air reservoir.
6. The pneumatic lift axle control system of clause 5, wherein the first fluid supply comprises the brake air supply and the second fluid supply comprises the brake air reservoir.
7. The pneumatic lift axle control system of clause 2, the command valve system further comprising an override valve configured to receive the first fluid pressure and to selectively communicate the first fluid pressure to the pilot valve system; and a trigger valve configured to receive the second fluid pressure and to selectively communicate the second fluid pressure to the pilot valve system.
8. The pneumatic lift axle control system of clause 7, the override valve and the trigger valve each comprising a solenoid valve.
9. The pneumatic lift axle control system of clause 2, the pilot valve system further comprising a latching valve configured to receive the first fluid pressure from the command valve system and to selectively communicate the first fluid pressure to a shuttle valve; and the shuttle valve configured to receive the second fluid pressure from the command valve system and the first fluid pressure from the latching valve, and to selectively communicate either the first fluid pressure or the second fluid pressure as a pilot signal to the lift axle actuator valve.
10. The pneumatic lift axle control system of clause 7, the pilot valve system further comprising a latching valve configured to receive the first fluid pressure from the override valve and to selectively communicate the first fluid pressure to a shuttle valve; and the shuttle valve configured to receive the second fluid pressure from the trigger valve and the first fluid pressure from the latching valve, and to selectively communicate either the first fluid pressure or the second fluid pressure as a pilot signal to the lift axle actuator valve.
11. The pneumatic lift axle control system of clause 10, the override valve further configured to vent fluid pressure from the latching valve; and the trigger valve further configured to vent fluid pressure from the shuttle valve.
12. The pneumatic lift axle control system of clause 11, the override valve comprising an override OFF state in which the override valve may communicate first fluid pressure from the first fluid supply to the latching valve; and an override ON state in which the override valve may communicate fluid pressure from the latching valve to a first exhaust vent.
13. The pneumatic lift axle control system of clause 12, the trigger valve comprising a trigger ON state in which the trigger valve may communicate second fluid pressure from the second fluid supply to the shuttle valve; and a trigger OFF state in which the trigger valve may communicate fluid pressure from the shuttle valve to a second exhaust vent.
14. The pneumatic lift axle control system of clause 13, the first exhaust vent and the second exhaust vent comprising a single exhaust vent.
15. The pneumatic lift axle control system of clause 10, the latching valve further comprising a first latch port configured to receive the first fluid pressure, a second latch port configured to communicate fluid with the shuttle valve, a third latch port configured to communicate fluid with the shuttle valve, and a fourth latch port configured to exhaust fluid pressure.
16. The pneumatic lift axle control system of clause 15, the shuttle valve further comprising a first shuttle port configured to receive the second fluid pressure, a second shuttle port configured to communicate the first fluid pressure or the second fluid pressure as a pilot signal to the lift axle actuator valve, a third shuttle port configured to communicate fluid with the third latch port, and a fourth shuttle port configured to communicate fluid with the second latch port.
17. The pneumatic lift axle control system of clause 16, the latching valve further comprising a latch shuttle configured to translate between a first latch position and a second latch position, wherein when the latch shuttle is in the first latch position, the third latch port is in fluid communication with the fourth latch port, and the first latch port and the second latch port are sealed from each other and from the third latch port and the fourth latch port, and when the latch shuttle is in the second position, the first latch port is in fluid communication with the third latch port, and the second latch port and the fourth latch port are sealed from each other and from the first latch port and the third latch port; and the shuttle valve further comprising a shuttle configured to translate between a first shuttle position and a second shuttle position, wherein when the shuttle is in the first shuttle position, the first shuttle port, the second shuttle port and the fourth shuttle port are in fluid communication with each other and sealed from the third shuttle port, and when the shuttle is in the second shuttle position, the third shuttle port, the second shuttle port and the fourth shuttle port are in fluid communication with each other and sealed from the first shuttle port.
18. The pneumatic lift axle control system of clause 17, wherein the latching valve comprises a latch body having a latch channel formed therein, the latch shuttle translatably disposed in the latch channel; the latch body comprising the first latch port, the second latch port, the third latch port and the fourth latch port, each latch port being in fluid communication with the latch channel; a first latch seal disposed between the latch shuttle and the latch channel so as to seal the second latch port from all of the other latch ports when the latch shuttle is in the first latch position or in the second latch position; a second latch seal disposed between the latch shuttle and the latch channel so as to seal the first latch port from the third latch port and the fourth latch port when the latch shuttle is in the first latch position; and a third latch seal disposed between the latch shuttle and the latch channel so as to seal the first latch port and the third latch port from the fourth latch port when the latch shuttle is in the second latch position.
19. The pneumatic lift axle control system of clause 18, the latching valve further comprising a spring disposed in the latch channel between an end of the latch shuttle and the latch body so as to bias the latch shuttle toward the first position.
20. The pneumatic lift axle control system of clause 19, the latching valve further comprising a fifth latch port formed in the latch body and in fluid communication with the latch channel, the fifth latch port configured to receive third fluid pressure from a third fluid supply; the latch shuttle comprising a latch bore extending axially through the latch shuttle from the end to a normally-closed one-way check valve disposed between the second latch seal and the third latch seal, the check valve being configured to permit fluid to flow from the latch bore to the latch channel but not from the latch channel to the latch bore; and a fourth latch seal disposed between the latch shuttle and the latch channel so as to seal the fifth latch port from all of the other latch ports when the latch shuttle is in the first latch position or in the second latch position.
21. The pneumatic lift axle control system of clause 20, further comprising a pressure actuator valve in sealed fluid communication between the fifth latch port and a vehicle air suspension system, the pressure actuator valve configured to open at a predetermined pressure to permit fluid from the vehicle air suspension system to flow into the fifth latch port and move the latch shuttle from the second latch position to the first latch position.
22. The pneumatic lift axle control system of clause 20, further comprising a normally-closed manually-operable valve in sealed fluid communication between the fifth latch port and the first fluid supply or the second fluid supply, the manually-operable valve configured to permit fluid from the fluid supply to which it is in fluid communication to flow into the fifth latch port and move the latch shuttle from the second latch position to the first latch position.
23. The pneumatic lift axle control system of clause 20, further comprising both the pressure actuator valve of clause 21 and the normally-closed manually-operable valve of clause 22.
24. The pneumatic lift axle control system of clause 20, wherein when the latch shuttle moves from the second latch position to the first latch position, fluid pressure flows through the latch bore, through the one-way check valve, and out through the fourth latch port.
25. The pneumatic lift axle control system of clause 24, wherein the latch seals are each annular seals.
26. The pneumatic lift axle control system of clause 25, wherein the latch seals are each o-rings.
27. The pneumatic lift axle control system of clause 17, wherein the shuttle valve comprises a shuttle body having a shuttle channel formed therein, the shuttle translatably disposed in the shuttle channel; the shuttle body comprising the first shuttle port, the second shuttle port, the third shuttle port and the fourth shuttle port, each shuttle port being in fluid communication with the shuttle channel; a first shuttle seal disposed between the shuttle and the shuttle channel so as to seal the third shuttle port from the first shuttle port, the second shuttle port and the fourth shuttle port when the shuttle is in the first shuttle position; and a second shuttle seal disposed between the latch shuttle and the latch channel so as to seal the first shuttle port from the second shuttle port, the third shuttle port and the fourth shuttle port when the shuttle is in the second shuttle position.
28. The pneumatic lift axle control system of clause 27, wherein the first shuttle seal, the second shuttle seal and the third shuttle seal are each an annular seal.
29. The pneumatic lift axle control system of clause 28, wherein the first shuttle seal, the second shuttle seal and the third shuttle seal are each an o-ring.
30. The pneumatic lift axle control system of clause 7, wherein when the override valve is in the OFF state and communicating first fluid pressure to the latching valve, and the trigger valve is in the OFF state, then the pilot valve system will communicate the first fluid pressure as a pilot signal to the lift axle actuator valve such that the lift axle actuator valve will deploy or maintain a lift axle in a raised position.
31. The pneumatic lift axle control system of clause 7, wherein when the override valve is in the OFF state and not communicating first fluid pressure to the latching valve, and the trigger valve is in the OFF state, then the pilot valve system will not communicate the first fluid pressure as a pilot signal to the lift axle actuator valve, and the lift axle actuator valve will deploy or maintain a lift axle in a lowered position.
32. The pneumatic lift axle control system of clause 7, wherein when the override valve is in the OFF state and communicating first fluid pressure to the latching valve, and the trigger valve is in the ON state, then the pilot valve system will communicate the second fluid pressure as a pilot signal to the lift axle actuator valve such that the lift axle actuator valve will deploy or maintain a lift axle in a raised position.
33. The pneumatic lift axle control system of clause 7, wherein when the override valve is in the OFF state and not communicating first fluid pressure to the latching valve, and the trigger valve is in the ON state, then the pilot valve system will communicate the second fluid pressure as a pilot signal to the lift axle actuator valve such that the lift axle actuator valve will deploy or maintain a lift axle in a raised position.
34. The pneumatic lift axle control system of clause 7, wherein when the override valve is in the ON state and venting fluid pressure from the latching valve, and the trigger valve is in the OFF state, then the pilot valve system will not communicate the first fluid pressure as a pilot signal to the lift axle actuator valve, and the lift axle actuator valve will deploy or maintain a lift axle in a lowered position.
35. The pneumatic lift axle control system of clause 7, the command valve system further comprising an electronic control unit configured to provide an override signal to the override valve and to provide a trigger signal to the trigger valve.
36. The pneumatic lift axle control system of clause 35, wherein when the electronic control unit provides an override signal to the override valve, then the override valve will switch from the OFF state to the ON state, and when the electronic control unit does not provide an override signal to the override valve, then the override valve will stay in the OFF state.
37. The pneumatic lift axle control system of clause 35, wherein when the electronic control unit provides a trigger signal to the trigger valve, then the trigger valve will switch from the OFF state to the ON state, and when the electronic control unit does not provide a trigger signal to the trigger valve, then the trigger valve will stay in the OFF state.
38. The pneumatic lift axle control system of clause 35, further comprising a load sensor configured to sense pressure in the vehicle air suspension and send a load signal to the electronic control unit.
39. The pneumatic lift axle control system of clause 38, the electronic control unit configured to calculate a vehicle weight or vehicle load weight from the load signal, and to determine whether the vehicle weight meets or exceeds a minimum weight threshold at or beyond which a lift axle may be deployed to a lowered position.
40. The pneumatic lift axle control system of clause 35, the electronic control unit configured to send a trigger signal to the trigger valve upon receiving a command signal.
41. The pneumatic lift axle control system of clause 35, the electronic control unit configured to send an override signal to the override valve upon receiving a command signal.
42. The pneumatic lift axle control system of clause 38, the electronic control unit configured to calculate a vehicle weight or vehicle load weight from the load signal, and to determine whether the vehicle weight meets or exceeds a maximum weight threshold at or beyond which a lift axle must be deployed to a lowered position.
43. The pneumatic lift axle control system of clause 38, the electronic control unit configured to send a trigger signal to the trigger valve upon determining that the vehicle weight meets or exceeds a maximum weight threshold.
44. The pneumatic lift axle control system of clause 38, the electronic control unit configured to send an override signal to the override valve upon determining that the vehicle weight meets or exceeds a maximum weight threshold.
45. The pneumatic lift axle control system of clause 35, further comprising a pressure sensor configured to sense pressure in first fluid supply and send a pressure signal to the electronic control unit.
46. The pneumatic lift axle control system of clause 45, the electronic control unit configured to use the pressure signal to determine whether the vehicle parking brake is engaged.
47. The pneumatic lift axle control system of clause 35, the electronic control unit configured to receive power from a vehicle power supply.
48. The pneumatic lift axle control system of clause 47, wherein when the electronic control unit does not receive power from the vehicle power supply, both the trigger valve and the override valve remain in or return to the OFF state.
49. A lift axle deployment system comprising a pilot-activated lift axle actuator valve configured to control fluid communication between a vehicle lift spring air supply and a lift axle lift spring and between a vehicle ride spring air supply and a lift axle ride spring; and a pneumatic lift axle control system of any of the clauses 1-48, the pneumatic lift axle control system configured to selectively communicate the first fluid pressure or the second fluid pressure as a pilot signal to the pilot-activated lift axle actuator valve.
50. The lift axle deployment system of clause 49, the actuator valve comprising a pneumatic actuator valve.
51. The lift axle deployment system of clause 50, the actuator valve comprising a first actuator port configured for fluid communication with a lift spring air supply; a second actuator port configured to exhaust fluid pressure; a third actuator port configured for fluid communication with a ride spring air supply; a fourth actuator port configured for fluid communication with a lift spring; and a fifth actuator port configured for fluid communication with a ride spring.
52. The lift axle deployment system of clause 51, the actuator valve comprising an OFF state in which the fourth actuator port is in fluid communication with the second actuator port and the fifth actuator port is in fluid communication with the third actuator port; and an ON state in which the fourth actuator port is in fluid communication with the first actuator port and the fifth actuator port is in fluid communication with the second actuator port.
53. The lift axle deployment system of clause 52 the actuator valve configured to receive a pilot signal, and to switch from an OFF state to an ON state when the pilot signal is received.
54. The lift axle deployment system of clause 53, the actuator valve configured to switch from an ON state to an OFF state when the pilot signal is not being received.
55. A heavy vehicle comprising a lift axle having a pneumatic lift spring configured for fluid communication with a lift spring air supply and a pneumatic ride spring configured for fluid communication with a ride spring air supply; an air brake system comprising a first fluid supply and a second fluid supply; and a lift axle deployment system of any of the clauses 49-54.
56. A heavy vehicle comprising a lift axle having a pneumatic lift spring configured for fluid communication with a lift spring air supply and a pneumatic ride spring configured for fluid communication with a ride spring air supply; an air brake system comprising a first fluid supply and a second fluid supply, a lift axle deployment system comprising a pilot-activated lift axle actuator valve configured to control communication between a vehicle lift spring air supply and a lift axle lift spring and between a vehicle ride spring air supply and a lift axle ride spring; and a pneumatic lift axle control system of any of the clauses 1-48, the pneumatic lift axle control system configured to selectively communicate the first fluid pressure or the second fluid pressure as a pilot signal to the pilot-activated lift axle actuator valve.
57. A heavy vehicle comprising a lift axle having a pneumatic lift spring configured for fluid communication with a lift spring air supply and a pneumatic ride spring configured for fluid communication with a ride spring air supply; an air brake system comprising a first fluid supply configured to provide a first fluid pressure and a second fluid supply configured to provide a second fluid pressure; a lift axle deployment system comprising a pilot-activated lift axle actuator valve of any of the clauses 50-54, the pilot-activated lift axle actuator valve configured to control communication between a vehicle lift spring air supply and a lift axle lift spring and between a vehicle ride spring air supply and a lift axle ride spring; and a pneumatic lift axle control system of any of the clauses 1-48, the pneumatic lift axle control system configured to selectively communicate the first fluid pressure or the second fluid pressure as a pilot signal to the pilot-activated lift axle actuator valve.
58. A method of deploying a vehicle lift axle, the method comprising when a vehicle having a lift axle is in park mode with the ignition on and the lift axle in a lowered position, determining a first vehicle weight; if the first vehicle weight is at or above a weight threshold, then maintaining the lift axle in a down position, and if the first vehicle weight is below a weight threshold, then automatically raising the lift axle to a raised position; after raising the lift axle, if the vehicle is placed in drive mode, then determining a second vehicle weight; and if the second vehicle weight is at or above the weight threshold, then automatically lowering the lift axle to a down position, and if the second vehicle weight is below the weight threshold, then maintaining the lift axle in a raised position.
59. The method of clause 58, if the second vehicle weight is below the weight threshold, then maintaining the lift axle in a raised position if the vehicle loses electrical power.
Although the disclosed subject matter and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the subject matter as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition, or matter, means, methods and steps described in the specification. As one will readily appreciate from the disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. For example, although the disclosed apparatus, systems and methods may be described with reference to a manual or manually-activated pressure reduction valve, an electric valve or other automatic electronic or mechanical valve may be used to accomplish relatively rapid reduction of air pressure. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, systems or steps.
This application claims priority to U.S. Provisional Patent Application 62/802,643 entitled “LIFT AXLE SYSTEM” filed Feb. 7, 2019, which is hereby entirely incorporated herein by reference.
Filing Document | Filing Date | Country | Kind |
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PCT/US2020/017347 | 2/7/2020 | WO | 00 |
Number | Date | Country | |
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62802643 | Feb 2019 | US |