CA2933915A1

CA2933915A1 - System and method for hydraulically controlling a suspension

Info

Publication number: CA2933915A1
Application number: CA2933915A
Authority: CA
Inventors: Dustin Kos; Tony Wong; Marlin Belanger
Original assignee: Option Industries Inc
Current assignee: RJ Enterprises Inc USA
Priority date: 2016-06-27
Filing date: 2016-06-27
Publication date: 2017-12-27

Abstract

A bed truck having multiple axles has a hydraulic suspension including multiple hydraulic cylinders for each axle, a ride height sensor associated with each hydraulic cylinder, a high pressure hydraulic circuit connecting each of the cylinders and accumulators to a hydraulic pressure source; a low pressure hydraulic circuit connecting each of the cylinders to a fluid tank; a plurality of valves operable to isolate operation of any one hydraulic cylinder from some or all of the other hydraulic cylinders. A control system is operable to control each of the hydraulic cylinders, either independently of all the other hydraulic cylinders, or in concert with one or more other hydraulic cylinders.

Description

SYSTEM AND METHOD FOR HYDRAULICALLY CONTROLLING A SUSPENSION
Field of the Invention [0001] The present invention relates to a hydraulic suspension control system and method for adjusting the suspension of a bed truck.
Background of the Invention

[0002] Bed trucks are used in the heavy transport and oil and gas service industry to load, transport and unload heavy loads, particularly in cases where cargo is too heavy for ordinary tractor/trailers to carry. Some bed trucks use a winch mounted at the front end of the bed to pull loads onto the bed over the rear of the bed

[0003] Bed trucks must be able to operate safely both on public highways and off-road in challenging terrain. Bed trucks must also comply with government regulations which relate to safe operation on public highways.

[0004] The suspension systems of these vehicles are important for operator comfort, productivity and safety. The suspension system may be adjustable depending upon the weight of the load applied to the equipment. A very heavy load may compress the suspension, forcing the vehicle body downward with respect to the axles, which can adversely affect the maneuverability of the vehicle. On the other hand, if the suspension is configured for relatively heavy loads, the vehicle may have an undesirably tall ride height under lighter loads.

[0005] As a result, many vehicles have automatic load leveling systems which employ one or more hydraulic cylinders between the axle and the frame of the vehicle to ensure that the frame is maintained at the proper height above the axle. When a heavy load is applied to the frame, the drop of the frame is sensed and additional hydraulic fluid is applied to the cylinder to raise the frame to a desired distance from the axle. When that heavy load is removed from the vehicle, the frame rises significantly above the axle. When this occurs hydraulic fluid is drained from the cylinder to lower the frame with respect to the axle. This type of automatic hydraulic load leveling system ensures that the frame and axle are maintained at the desired separation regardless of the size of the load applied to the vehicle.

[0006] The hydraulic cylinder may also function as a shock absorber by regulating the flow of fluid from a chamber on one side of the piston to a chamber on the other side as the vehicle bounces when traveling over uneven ground. Although this shock absorbing action is beneficial to creating a smoother ride and greater operator comfort, there are times when it is necessary to lock-out an axle to produce a "solid axle". For example, when the vehicle is carrying a heavy load there may not be a need for shock absorber action of the suspension as the tire perform that task. Also the shock absorber action may not be required at relatively low speeds.
Summary of the Invention

[0007] In one aspect, the invention comprises a hydraulic suspension which is configured to accommodate the difference in operation from highway operation to off-road operation, and to facilitate loading and unloading of heavy loads in challenging terrain.

[0008] In one aspect, the invention comprises a bed truck having a front axle and at least two rear axles, and a hydraulic suspension comprising:
a.
first and second hydraulic cylinders disposed between the frame and opposing ends of a first rear axle, and third and fourth hydraulic cylinders disposed between the frame and opposing ends of a second rear axle, wherein each hydraulic cylinder is associated with accumulator;

b. a hydraulic fluid pressure source and a fluid tank c. a ride height sensor associated with each hydraulic cylinder;
d. a high pressure hydraulic circuit connecting each of the cylinders and accumulators to the pressure source;
e. a low pressure hydraulic circuit connecting each of the cylinders to the fluid tank;
f. wherein the high pressure hydraulic circuit comprises a plurality of valves operable to isolate operation of any one hydraulic cylinder from some or all of the other hydraulic cylinders; and wherein one or more valves are operable to lock the position of any one or more of the hydraulic cylinders; and g.
a control system operably connected to each of the ride height sensors and each of the plurality of valves to control each of the hydraulic cylinders, either independently of all the other hydraulic cylinders, or in concert with one or more other hydraulic cylinders.

[0009] In another aspect, the invention may comprise a method of controlling the ride height of a bed truck having a front axle and at least two rear axles, and a hydraulic suspension comprising a hydraulic suspension comprising first and second hydraulic cylinders disposed between the frame and opposing ends of a first rear axle, and third and fourth hydraulic cylinders disposed between the frame and opposing ends of a second rear axle, wherein each hydraulic cylinder is associated with accumulator; a hydraulic fluid pressure source and a fluid tank; a ride height sensor associated with each hydraulic cylinder; a high pressure hydraulic circuit connecting each of the cylinders and accumulators to the pressure source; a low pressure hydraulic circuit connecting each of the cylinders to the fluid tank; wherein the high pressure hydraulic circuit comprises a plurality of valves operable to isolate operation of any one hydraulic cylinder from some or all of the other hydraulic cylinders; and wherein one or more valves are operable to lock the position of any one or more of the hydraulic cylinders; and a control system operably connected to each of the ride height sensors and each of the plurality of valves to control each of the hydraulic cylinders, either independently of all the other hydraulic cylinders, or in concert with one or more other hydraulic cylinders, in response to loading or unloading conditions.
Brief Description of the Drawings

[0010] The invention will now be described by way of an exemplary embodiment with reference to the accompanying simplified, diagrammatic, not-to-scale drawings. Any dimensions provided in the drawings are provided only for illustrative purposes, and do not limit the invention as defined by the claims. In the drawings:

[0011] Figure 1 shows a bed truck with three rear axles and a hydraulic suspension of the present invention.

[0012] Figure 2 is a schematic representation of one embodiment of a hydraulic circuit of the present invention.

[0013] Figure 3 is a detail view of one portion of figure 2.

[0014] Figure 4 is a detail view of another portion of Figure 2.

[0015] Figure 5 shows schematically a load being loaded on to the bed truck from the rear,

[0016] Figure 6 shows schematically the response of a hydraulic suspension to uneven terrain.

[0017] Figure 7 shows schematically the response of a hydraulic suspension to inclined terrain.
Detailed Description of the Invention

[0018] The present invention relates to a hydraulic suspension system for a bed truck.

[0019] As used herein, a "bed truck" is a heavy duty commercial vehicle designed to transport heavy loads on a flat bed. Bed trucks have at least one front axle, and typically have two or more rear axles. Bed trucks are used in the oil and gas service industry to load, transport and unload drilling or service rig substructures, other heavy rig components, or other heavy loads.

[0020] In one aspect, as shown in Figure 1, the invention comprises a bed truck (10) having a sprung mass comprising a truck frame (12) and a bed (14), and an unsprung mass comprising at least one front axle (16) and three rear axles (18, 19, 20), wherein each axle is separated from the frame by at least a pair of hydraulic cylinders (22, 24). Each hydraulic cylinder is individually controlled to control the distance between the axle and the frame, thereby controlling the ride height of the truck at each hydraulic cylinder. Each cylinder may controlled independently, so as to act in concert with some or all of the others, or differently, depending on the circumstances.
While the hydraulic cylinders may provide suspension dampening functionality, in one embodiment, at least the rearmost axle (20), and preferably each axle, can be individually locked so as to maintain a minimum ride height at that axle,

[0021] The hydraulic suspension of the present invention utilizes conventional hydraulic suspension components, and as such, a detailed description of those components is not required to allow one skilled in the art to understand the configuration and operation of the claimed invention. A schematic representation of one embodiment of a hydraulic circuit is shown in Figure 2, using symbols and terminology well known to those skilled in the art.

[0022] In one embodiment, the hydraulic system comprises an open hydraulic system with a high pressure circuit including a hydraulic pump pressure source (P) connected to the high pressure side of each hydraulic cylinder, and a lower pressure circuit returning hydraulic fluid to a return tank (T) from the lower pressure side of each hydraulic cylinder.

[0023] The pressure side of each hydraulic cylinder are hydraulically connected to a hydraulic pressure source with accumulators (101) associated with each cylinder (22,

24). Normally closed solenoid valves (103) are provided to allow for selective actuation of either the driver side or passenger side hydraulic cylinder on an individual axle. A drivers side control valve (105) and a passenger side control valve (107), along with normally closed solenoid valve (109) allows for coordinated actuation of all the hydraulic cylinders along the driver side or passenger side, subject to the position of the valves (103) for each axle.
[0024] A suspension dampening valve (111) is connected to the pressure source both directly and from the accumulators (101), and the low pressure side returning to the fluid tank.

[0025] Each hydraulic cylinder is controlled with a user-actuated control system, which is configured to specify the ride height at each axle. The control system may comprise a user interface, such as a touch screen input, and a microprocessor which is configured as the control system and operatively connected to the necessary hydraulic valves and pumps, which are shown schematically in Figure 1

[0026] In one embodiment, axle position or ride height feedback is measured through a magnetostrictive position sensor installed within a hydraulic cylinder. Ride height manipulation is pressure controlled by means of proportional pressure reducing/relieving valves for each cylinder on each axle. The microprocessor may comprise a programmable logic controller which reads in the ride height from the magnctostrictive position sensor and compares it to the desired height. A proportional¨integral¨derivative (PID) controller is then used to manipulate the pressure required to achieve the desired ride height.

[0027] Ride dampening is provided via nitrogen filled hydraulic accumulators directly tied to the cap end of each ride height axle cylinder. The ride dampening is controlled via proportional metering controls that meter fluid in and out of the accumulators.

[0028] In one embodiment, hydraulic power is provided by a pressure compensated load sensing piston pump.

[0029] In one embodiment, the bed truck is configured to facilitate self-loading from the rear, whereby a payload (L) is first placed onto the rear of the bed and then slid onto the bed along the longitudinal axle of the truck, typically by means of a winch (W) mounted at the front end of the bed. During the loading process, shown schematically in Figure 5, the entire weight of the load bears on the rear edge of the bed, and thus also bears on the rearmost axle.
In one embodiment, the rearmost axle (20) may be locked at a minimum ride height to maintain the height of the truck. Thus, the truck effectively can support the entire payload on this rear axle (20) while loading and unloading. This allows the pivoting point to become the rear axle when balancing the rear hanging load with the weight of the truck itself. Accordingly, self-loading and unloading may be accomplished with very high payloads, while maintaining truck and payload greater stability. In such cases of a bed load, the rear axle approaches a balance point supporting all payload and the majority of the truck weight. Otherwise, the front end of the truck would become unloaded and in extreme cases, the front wheels might rise off the ground, not allowing the truck to steer.

[0030] When configured for public highway use, the suspension utilizes linked pressure control for each hydraulic cylinder using a suspension dampening valve (111) and the accumulators (101), which are all interconnected, allowing compliance with typical highway safety regulations, such as those imposed by Transport Canada.

[0031] Each axle may also be locked to maintain a minimum ride height, but still remain pressure compensated at ride heights greater than the minimum. Accordingly, the suspension permits ride height in the normal course, so long as the ride height exceeds a minimum user-determined value. The tires on a non-point loaded axle may then maintain traction and propelling torque even where heavy loads are present on another axle.

[0032] The accumulators associated with each hydraulic cylinder may also allow an axle which is locked at a minimum ride height to extend above the minimum if going over a hole or on uneven terrain, but the axle will only retract to its locked minimum ride height position. The other non-locked axles maintain ride height insuring the propelling traction needed and shared loading on the axles.

[0033] In one embodiment, the system may also be configured to vary ride height laterally.
Thus, the left side of the axle may be set at a different ride height than the right side. Thus, the bed truck may load or unload unbalanced payloads and/or on uneven terrain with greater stability.

[0034] In another example, a bed truck may be used as a crown transport unit, where a drilling rig mast is transported in one piece to or from an off-road location. A mast may be 100 to 200 feet long and is supported with a derrick dolly on other end. During transport, the dolly or mast may lean, requiring the hydraulic suspension to compensate to match the lean.
Otherwise, the connections between the mast and the truck may be damaged or shear off entirely. This may be done by automatically or manually changing the set points on the control system

[0035] The terminology used herein is for the purpose of describing particular examples only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an"
and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The term "another", as used herein, is defined as at least a second or more. The terms "including" and "having," as used herein, are defined as comprising (i.e., open language). The term "coupled," as used herein, is defined as "connected," although not necessarily directly, and not necessarily mechanically. "Communicatively coupled" refers to coupling of components such that these components are able to communicate with one another through, for example, wired, wireless or other communications media. The term "communicatively coupled" or "communicatively coupling" includes, but is not limited to, communicating electronic control signals by which one element may direct or control another. The term "configured to" describes hardware, software or a combination of hardware and software that is adapted to, set up, arranged, built, composed, constructed, designed or that has any combination of these characteristics to carry out a given function. The term "adapted to" describes hardware, software or a combination of hardware and software that is capable of, able to accommodate, to make, or that is suitable to carry out a given function.

[0036] The terms "computer" or "processor" or "control system" describe examples of a suitably configured processing system adapted to implement one or more examples herein.
Any suitably configured processing system is similarly able to be used by examples herein, for example and not for limitation, a personal computer, a laptop computer, a tablet computer, a smart phone, a personal digital assistant, a workstation, or the like. A processing system may include one or more processing systems or processors. A processing system can be realized in a centralized fashion in one processing system or in a distributed fashion where different elements are spread across several interconnected processing systems.

[0037] The terms "computing system", "computer system", and "personal computing system", describe a processing system that includes a user interface and which is suitably configured and adapted to implement one or more examples of the present disclosure,

[0038] The term "portable electronic device" is intended to broadly cover many different types of electronic devices that are portable or that can be transported between locations by a user. For example, and not for any limitation, a portable electronic device can include any one or a combination of the following: a wireless communication device, a laptop personal computer, a notebook computer, a desktop computer, a personal computer, a smart phone, a Personal Digital Assistant, a tablet computer, gaming units, remote controller units, and other handheld electronic devices that can be carried on one's person.

[0039] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description herein has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the examples in the form disclosed.
Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the examples presented or claimed, The disclosed examples were chosen and described in order to best explain the principles of the examples and the practical application, and to enable others of ordinary skill in the art to understand the various examples with various modifications as are suited to the particular use contemplated. It is intended that the appended claims below cover any and all such applications, modifications, and variations within the scope of the examples.

Claims

WHAT IS CLAIMED IS:

1. A bed truck having a front axle and at least two rear axles, and a hydraulic suspension comprising:
a. first and second hydraulic cylinders disposed between the frame and opposing ends of a first rear axle, and third and fourth hydraulic cylinders disposed between the frame and opposing ends of a second rear axle, wherein each hydraulic cylinder is associated with accumulator;
b. a hydraulic fluid pressure source and a fluid tank c. a ride height sensor associated with each hydraulic cylinder;
d. a high pressure hydraulic circuit connecting each of the cylinders and accumulators to the pressure source, and a low pressure hydraulic circuit connecting each of the cylinders to the fluid tank;
c. wherein the high pressure hydraulic circuit comprises a plurality of valves operable to isolate operation of any one hydraulic cylinder from some or all of the other hydraulic cylinders; and wherein one or more valves are operable to lock the position of any one or more of the hydraulic cylinders at a minimum ride height; and g. a control system operably connected to each of the ride height sensors and each of the plurality of valves to control each of the hydraulic cylinders, either independently of all the other hydraulic cylinders, or in concert with one or more other hydraulic cylinders.

2. The bed truck of claim I wherein the control system is operable to control each of the hydraulic cylinders associated with a rearmost axle to lock the rearmost axle at a minimum ride height.

3. The bed truck of claim 2 wherein the control system is operable to control each of the hydraulic cylinders associated with a rearmost axle to lock the rearmost axle at a minimum ride height while allowing all other hydraulic cylinders to adjust ride height as necessary.

4. A method of controlling the ride height of each axle of a bed truck having a front axle and at least two rear axles, and a hydraulic suspension comprising first and second hydraulic cylinders disposed between the frame and opposing ends of a first rear axle, and third and fourth hydraulic cylinders disposed between the frame and opposing ends of a second rear axle, wherein each hydraulic cylinder is associated with accumulator; a hydraulic fluid pressure source and a fluid tank; a ride height sensor associated with each hydraulic cylinder; a high pressure hydraulic circuit connecting each of the cylinders and accumulators to the pressure source and a low pressure hydraulic circuit connecting each of the cylinders to the fluid tank;
wherein the high pressure hydraulic circuit comprises a plurality of valves operable to isolate operation of any one hydraulic cylinder from some or all of the other hydraulic cylinders; and wherein one or more valves are operable to lock the position of any one or more of the hydraulic cylinders; and a control system operably connected to each of the ride height sensors and each of the plurality of valves to control each of the hydraulic cylinders, either independently of all the other hydraulic cylinders, or in concert with one or more other hydraulic cylinders, in response to loading or unloading conditions.

5. The method of claim 4 wherein the bed truck is being loaded from the rear by a heavy object sliding over a rear edge of the bed truck, comprising the step of locking a rearmost axle at a minimum ride height.

6. The method of claim 5 wherein all other hydraulic cylinders are allowed to adjust ride height as necessary.