The present invention relates to an electro-hydraulic modulating valve pedal assembly to achieve a desired braking demand and for other applications.
A variety of valves are designed for vehicles that are equipped with hydraulic power devices. For example, it is known to provide pedal-actuated hydraulic valves for forestry equipment, agricultural equipment, construction equipment, military equipment, and mining equipment. These hydraulic valves can be installed in conjunction with floor mounted pedals or suspended pedals to provide normal and emergency braking, and to operate industrial equipment.
Hydraulic circuits for pedal-actuated hydraulic valves typically include a pump or an accumulator and include a braking system or an industrial tool. If an accumulator is used, the accumulator can include a charging valve to provide a pressurized hydraulic fluid to the hydraulic brake valve. Known hydraulic brake modulation valves include a pressure port, a tank port, and a working port. These valves are mechanically actuated with a spool for controlling the flow of pressurized hydraulic fluid to the working port for use by the braking system or the industrial tool.
Despite the widespread acceptance of pedal-actuated hydraulic valves, there remains a continued need for an improved hydraulic pedal modulating valve assembly that can be better integrated into electronic control systems, including anti-lock braking (ABS) systems and autonomous driving systems. In particular, there remains a continued need for a hydraulic pedal assembly that can provide hydraulic pressure in response to both foot pedal actuation and electrical control inputs.
An improved electro-hydraulic modulating valve pedal assembly is provided. The electro-hydraulic pedal assembly is adapted to control the flow of hydraulic fluid both manually, through actuation of a pedal, and electrically, through activation of a solenoid. The pedal assembly is well suited for electronic control systems, including brake electronic control units (ECUs) for ABS braking, emergency braking, autonomous operation, and other applications.
In one embodiment, the electro-hydraulic pedal assembly includes a push rod that is mechanically coupled to a pedal, a solenoid that is magnetically coupled to the push rod (having a magnetic armature), and a spool valve that is configured to vary a hydraulic output in response to the force exerted by the push rod. The solenoid surrounds at least a portion of the magnetic armature for applying a magnetic force and driving the push rod in a first (downward) direction, the magnetic force being proportional to an electrical current supplied to the solenoid. The spool valve includes a spool that is concentrically arranged within a valve body, such that movement of the push rod in the first (downward) direction causes a corresponding movement of the spool in the first (downward) direction. In this position, the spool valve provides fluid communication between a pressure port and a work port. A return spring returns the spool valve to the neutral position. In the neutral position, the spool valve provides fluid communication between the working port and a tank port.
In the current embodiment, the electro-hydraulic pedal assembly includes a three-position hydraulic spool valve having two valve operators: a pedal and a solenoid. The hydraulic valve includes a working port coupled to a working unit, a pressure port coupled to a hydraulic pump, and a tank port coupled to a hydraulic reservoir. In the first valve position, the working port is coupled to the tank port to prevent unwanted pressure buildup from actuating the working unit. In the second valve position, all three ports are closed off from each other. In the third valve position, the pressure port is coupled to the working port. The valve operators function independently of each other and in parallel, such that the spool valve can respond to actuation by the pedal—independently of the energized state of the solenoid—and can respond to actuation by the solenoid—independently of the position of the pedal, to rapidly transition from one position to the next, optionally in response to electronic control signals from a brake ECU.
These and other features and advantages of the present invention will become apparent from the following description of the invention, when viewed in accordance with the accompanying drawings and the appended claims.
Referring to
The foot pedal 12 generally includes a pedal body 22 with an upward-facing contact surface 24. As shown in
A cross-section of the foot pedal piston 34 in the neutral position is shown in
In the neutral position shown in
Referring again to
Each spring S1, S2, S3 is a compression coil spring in the illustrated embodiment, but can be a wave spring in other embodiments. The compression coil spring or the wave spring can be linear or progressive, optionally a dual-rate coil spring, further optionally a progressive coil spring. The armature 17 is formed of a ferromagnetic material, for example iron, and extends concentrically through a central bore of the pedal assembly 10. The solenoid coil 48 surrounds at least a portion of the armature 17 for applying a magnetic force and driving the push rod 16 in a first (downward) direction, the magnetic force being proportional to the electrical current supplied to the solenoid coil 48. The solenoid assembly 20 additionally includes a socket 50 for power cables, which provide the electrical current to the solenoid coil 48.
As also shown in
More specifically, each of the ports 54, 56, and 58 are in fluid communication with the bore 46. The bore 46 includes a first annular surface 60 and a second annular surface 62 on either side of the work port 56. These surfaces cooperate with the spool 44 to selectively direct fluid to the work port 56. The spool 44 includes a first annular portion 64 and a second annular portion 66. These annular portions are configured to coincide with the first annular surface 60 and the second annular surface 62 of the bore 46. The spool 44 also includes a shoulder 68 proximate the upper end of the spool valve 18. Also at the upper end of the spool valve 18, a fifth spring S5 is disposed in the bore 46, the fifth spring S5 optionally being a compression coil spring. A washer 72 is disposed between the shoulder 68 and the fifth spring S5 to provide a mechanical stop to the spring compression. In addition, the washer 72 functions to define the neutral position of the spool 44, which allows a faster release of work port pressure than would otherwise be possible.
In use, when pressurized fluid is desired at the working port 56, the foot pedal 12 is manually compressed and/or the solenoid coil 48 is energized. The push rod 16 moves in the first (downward) direction, causing the spool 44 to likewise move in the first (downward) direction. The first, second, third, and fourth springs S1, S2, S3, S4 provide the desired pedal feel during compression of the foot pedal 12. If the solenoid coil 48 is energized without movement of the foot pedal 12, only the second spring S2 and the fourth spring S4 oppose downward travel of the push rod 16, and the piston 34 remains in the neutral position. In this position, pressurized fluid is permitted to flow from the pressure port 54 to work port 56 for operation of a working unit. At the same time, fluid flow to the tank port 58 is obstructed by a close fit between the lower annular surface 62 of the valve body and the lower annular portion 66 of the spool 44. Upon the desired release of the pressurized fluid, the foot pedal 12 is depressed and/or the solenoid coil 48 is de-energized. The spool 44 moves in the second (upward) direction by the force from the second spring S2 and the fourth spring S4 and by the imbalance of fluid pressure forces acting on the spool 44. The combination of the return spring force and the force resulting from residual work port pressure compresses the fifth spring S5 and shifts the spool 44 in the second (upward) direction. In this neutral position, shown in
Referring now to
As noted above in connection with
Referring now to
Referring now to
The above description is that of current embodiments. Various alterations and changes can be made without departing from broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. This disclosure is presented for illustrative purposes and should not be interpreted as an exhaustive description of all embodiments or to limit the scope of the claims to the specific elements described in connection with these embodiments. The present invention is not limited to only those embodiments that include all of these features or that provide all of the stated benefits, except to the extent otherwise expressly set forth in the issued claims. Any reference to claim elements in the singular, for example, using the articles “a,” “an,” “the” or “said,” is not to be construed as limiting the element to the singular.
This application is the National Stage of International Application No. PCT/US2020/028683 filed on Apr. 17, 2020, which claims priority to and all advantages of U.S. Provisional Patent Application No. 62/835,215 filed on Apr. 17, 2019, the contents of which are incorporated herein by reference.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/US2020/028683 | 4/17/2020 | WO |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2020/214915 | 10/22/2020 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
3429340 | Opel et al. | Feb 1969 | A |
6405837 | Muramoto | Jun 2002 | B1 |
6866348 | Ewel | Mar 2005 | B2 |
20030070715 | Royle | Apr 2003 | A1 |
20060053957 | Ewel et al. | Mar 2006 | A1 |
Number | Date | Country |
---|---|---|
207875610 | Sep 2018 | CN |
S59124450 | Jul 1984 | JP |
3667533 | Jul 2005 | JP |
2017019316 | Jan 2017 | JP |
101048745 | Jul 2011 | KR |
Entry |
---|
International Search Report for PCT/US2020/028683 dated Sep. 14, 2020, 4 pages. |
Machine assisted English translation of JPS59124450A obtained from https://worldwide.espacenet.com/ on Nov. 23, 2021, 4 pages. |
Machine assisted English translation of JP3667533A obtained from https://patents.google.com/patent on Oct. 28, 2021, 6 pages. |
Machine assisted English translation of KR101048745B1 obtained from https://patents.google.com/patent on Oct. 28, 2021, 7 pages. |
Machine assisted English translation of JP2017019316A obtained from https://patents.google.com/patent on Oct. 28, 2021, 6 pages. |
Machine assisted English translation of CN207875610U obtained from https://patents.google.com/patent on Oct. 28, 2021, 12 pages. |
Number | Date | Country | |
---|---|---|---|
20220219652 A1 | Jul 2022 | US |
Number | Date | Country | |
---|---|---|---|
62835215 | Apr 2019 | US |