Proportional hydraulic two-stage valve

Abstract

Having one valve (100): an excitable electromagnet (210) with a magnetic chamber (218) in which a magnetic pin (212) is housed; a proportional piston (310) with a piston body (312) and a piston sleeve (320), wherein the piston sleeve (320) accommodates the piston body (312) and a supply section (326) with at least one supply port (P, Ps) in fluid connection with a hydraulic fluid supply source (110) and a tank section (324) with at least one tank port (P, P) T) in fluid communication with a reservoir (120) for the hydraulic fluid, wherein the piston body (312) has a first fluid channel (318) extending from a first opening (318o1) to a second opening (318o2), and wherein the first opening (318o1) of the piston sleeve (320) and the second opening (318o2) are facing the magnetic pin (212), and wherein the first opening (318o1) is not able to come into fluid communication with the tank section (324) of the piston sleeve (320); a mechanical connection (400) that couples the magnetic pin (212) to the piston body (312), and wherein the mechanical connection (400) has at least a partial second fluid channel (202, 424) that extends through the piston sleeve (320) to the tank section (324); and a flow path (202, 424, 318) for hydraulic fluid from the supply source (110), wherein the flow path (202, 424, 318) includes the first fluid channel (318) and the second fluid channel (202, 424), and wherein, when the excitable electromagnet (210) is de-energized, the first opening (318o1) of the first fluid channel (318) is not connected to the at least one supply port (P, P) S ) of the supply section (326).

Description

PRIORITY CLAIMS

[0001] This application claims priority to PCT application No. PCT / US20 / 39837, filed on June 26, 2020, and to US patent application No. 16 / 913,279, filed on June 26, 2020. The entire contents of the above-mentioned applications are incorporated herein by reference. TECHNICAL AREA

[0002] This disclosure relates to a proportional hydraulic two-stage valve and a main stage of a two-stage valve. BACKGROUND

[0003] Hydraulics typically refers to the use of incompressible fluids of relatively high density (i.e., hydraulic fluid) to perform work. Hydraulic systems may use an arrangement of one or more hydraulic circuits to perform this work (e.g., moving an object). A hydraulic circuit generally includes components that perform operations based on fluid dynamics. Hydraulic circuits often control fluid flow, and therefore fluid pressure, to perform work either inside the circuit or outside the circuit. A hydraulic circuit can be controlled mechanically and / or electrically (e.g., by electrical signals). Hydraulic valves are mechanical devices used to regulate fluid flow within a hydraulic circuit; they can be used to close a line, redirect pressurized fluid, or control the flow level to a specific area.WO 2015 / 028 108 A1 relates to a valve device, in particular in the form of a proportional pressure control valve, with a valve piston that is guided longitudinally in a valve housing and connects a working port to a pressure supply port and a tank or return port, depending on its position, and that can be controlled by an actuating device, in particular in the form of an energizable actuating magnet. According to the invention, a control device is provided between the valve piston and the actuating device, which allows the valve piston to be depressurized on its piston side facing the actuating device in the direction of the tank or return port in such a way that the valve piston moves in the direction of the actuating device under the supply and / or working port pressure that can be controlled during operation when the actuating device is not actuated.DE 10 2005 056 039 A1 relates to a hydraulic / pneumatic control valve with a fail-safe function, actuated by an actuating element of an actuating device. In the event of a malfunction of the control valve, the valve relieves pressure at a connection point in the unactuated state, regardless of the position of a control spool at the connection point T. The actuating element at the connection point has a coaxial seal, which, in normal operating conditions, creates a force-locking and form-locking connection between the control spool and the actuating element. In the event of a malfunction, the connection point is relieved via at least one line connection between the storage space and the connection point. DE 39 38 417 C1 relates to a valve arrangement, e.g.a proportional valve for controlling the pressure of a connected fluid unit, with a control element which can be adjusted by means of a servo motor against a restoring force acting on the control element from an initial position in which the fluid unit communicates with a low-pressure reservoir, into an operating position in which the fluid unit communicates with a pressure source via a connection controlled by the control element and / or is separated from the low-pressure reservoir. SUMMARY

[0004] One object underlying this disclosure is to propose an improved proportional hydraulic two-stage valve and an improved main stage of a two-stage valve. This object is achieved by a valve having the features of claims 1 and 11, and a main stage of a two-stage valve having the features of claim 22, respectively. Further embodiments are the subject of the dependent claims. One aspect of the disclosure provides a proportional two-stage hydraulic valve. The valve includes a pilot stage with a solenoid, the solenoid comprising a solenoid chamber housing a solenoid pin. When the solenoid is energized, the solenoid actuates the solenoid pin. The valve also includes a main stage with a proportional piston housed in a piston sleeve. The piston sleeve includes a supply section having at least one supply port in fluid communication with a hydraulic fluid supply source, and a tank section having at least one tank port in fluid communication with a reservoir for the hydraulic fluid.The proportional piston includes a piston body with a first fluid channel that receives hydraulic fluid from the supply source when an opening for the first fluid channel in the piston body is aligned with the at least one supply port of the supply section. When the solenoid is energized and the opening for the first fluid channel in the piston body is aligned with the at least one supply port of the supply section, hydraulic fluid from the supply source exerts a force on the piston body in an actuating direction through the solenoid pin and flows to a second fluid channel within the pilot-operated stage of the valve. The second fluid channel is in fluid communication with the hydraulic fluid reservoir.

[0005] Implementations of the disclosure may include one or more of the following optional features. In some implementations, the piston body includes at least one working port along a central axis of the piston body. In this case, the piston body may include a chamber along the central axis of the piston body, wherein the chamber may include the at least one working port configured to selectively communicate between the at least one supply port of the supply portion and the at least one tank port of the tank portion. Optionally, the piston body may have a top surface facing the magnetic pin.In this case, when the solenoid is energized and the opening for the first fluid channel in the piston body is aligned with the at least one supply port of the supply section, hydraulic fluid from the supply source can exert the force on the piston body against the upper surface of the piston body.

[0006] In some examples, the valve includes a mechanical connection between the pilot stage and the main stage, wherein actuation of the magnetic pin couples the magnetic pin to the mechanical connection to move the piston body within the piston sleeve. The piston body can move within the piston sleeve in the actuation direction in first and second states. During the first state, actuation of the magnetic pin can drive the mechanical connection into the piston body and move the piston body to a first position. During the second state, the piston body can decouple from the mechanical connection, and the force exerted on the piston body by the hydraulic fluid flowing through the first fluid channel can move the piston body along the piston sleeve from the first position to a second position farther from the mechanical connection.The mechanical connection may include, but is not limited to, a flow-restricting element such as a ball and an annular seat for the ball. The piston body may have a connecting rod with a diameter smaller than the inner diameter of the annular seat for the ball. Here, during the first state and the second state, hydraulic fluid flowing through the first fluid channel of the piston body may communicate with the second fluid channel along a fluid path between the connecting rod and the annular seat, and the hydraulic fluid may exert a corresponding force on the ball to allow the hydraulic fluid to flow between the annular seat and the ball to the second fluid channel.The valve may include a ball chamber housing the ball and the annular seat for the ball, wherein the ball chamber may include at least one opening that at least partially defines the second fluid channel. In some implementations, the tank portion of the piston sleeve is located at a location closest to the electromagnet, and the first passage extends a length of the piston body from a top surface of the piston body, wherein a length of the first passage is greater than a length of the tank portion of the piston sleeve.

[0007] Another aspect of the disclosure provides a first stage of a two-stage valve. The first stage of the two-stage valve includes a piston body having a control fluid channel. The first stage of the two-stage valve also includes a piston sleeve in which the piston body is housed. The piston sleeve includes a supply portion having at least one supply port in fluid communication with a hydraulic fluid supply source and a tank portion having at least one tank port in fluid communication with a reservoir for the hydraulic fluid. When the first stage is deactivated, the control fluid channel in the piston body is closed off from receiving hydraulic fluid from the hydraulic fluid supply source.When the control fluid channel in the piston body is aligned with the at least one supply port of the supply section, hydraulic fluid flows from the supply source through the control fluid channel to exert a driving force on the piston body to move the piston body along a length of the piston sleeve in an actuating direction against a restoring force.

[0008] This aspect may include one or more of the following optional features. In some configurations, the piston body includes at least one working port along a central axis of the piston body. In this case, the piston body may include a chamber along the central axis of the piston body, and the chamber may include the at least one working port configured to selectively communicate between the at least one supply port of the supply section and the at least one tank port of the tank section.

[0009] In some examples, the piston body includes a lower surface configured to receive the restoring force and an upper surface opposite the lower surface. In this example, as the piston body moves along the length of the piston sleeve, a control volume within the piston sleeve increases in volume beyond the upper surface of the piston body. The driving force exerted by the hydraulic fluid from the control fluid channel may increase in magnitude proportional to an increase in the control volume above the top of the piston body.

[0010] In some implementations, the piston body includes a lower surface configured to receive the restoring force and an upper surface opposite the lower surface. In this embodiment, the piston body includes a chamber along a central axis of the piston body, the chamber including the at least one working port configured to selectively communicate between the at least one supply port of the supply section and the at least one tank port of the tank section. An opening for the control fluid channel is located at a location along a length of the piston body that is closer to the bottom surface of the piston body than the at least one working port.

[0011] In some configurations, the piston body includes a lower surface configured to receive the restoring force and an upper surface opposite the lower surface. In this configuration, the piston body includes a chamber along a central axis of the piston body, and the chamber includes the at least one working port configured to selectively communicate between the at least one supply port of the supply section and the at least one tank port of the tank section. Further, a first distance between the at least one working port and the upper surface is less than a second distance between an opening for the control fluid channel and the upper surface.

[0012] In some examples, when the control fluid channel in the piston body is aligned with the at least one supply port of the supply section, a first portion of the hydraulic fluid from the supply source flows through the control fluid channel to apply the drive force to the piston body, and a second portion of the hydraulic fluid from the supply source flows through the control fluid channel and out of the piston sleeve to the reservoir. Here, the piston body may have a lower surface configured to receive the restoring force and an upper surface opposite the lower surface.As the piston body moves along the length of the piston sleeve, a control volume within the piston sleeve may increase in volume above the top surface of the piston body, and in response to the increase in volume above the top surface of the piston body, the volume of the second portion of hydraulic fluid from the supply source flowing through the control fluid channel and out of the piston sleeve to the reservoir may decrease.

[0013] In some implementations, an activated position for the piston body corresponds to a position where at least one working port in the piston body is aligned with the at least one supply port of the supply section. As the piston body moves along the length of the piston sleeve in the actuation direction to the activated position, an opening of the control fluid channel aligns with the at least one supply port of the supply section before the at least one working port aligns with the at least one supply port of the supply section.

[0014] Another aspect of the disclosure provides a valve. The valve includes an energizable electromagnet having a magnetic chamber in which a magnetic pin is housed. The valve also includes a proportional piston having a piston body and a piston sleeve. The piston sleeve houses the piston body and includes a supply portion having at least one supply port in fluid communication with a hydraulic fluid supply source and a tank portion having at least one tank port in fluid communication with a reservoir for the hydraulic fluid. The piston body includes a first fluid channel extending from a first opening to a second opening. The first opening faces the piston sleeve, and the second opening faces the magnetic pin. The valve also includes a mechanical connection connecting the magnetic pin to the piston body.The mechanical connection at least partially comprises a second fluid channel extending through the piston sleeve to the tank portion. The valve also includes a flow path for hydraulic fluid from the supply source, the flow path including the first fluid channel and the second fluid channel. When the energizable solenoid is de-energized, the first opening of the first fluid channel is not aligned with the at least one supply port of the supply portion.

[0015] This aspect may include one or more of the following optional features. In some examples, the mechanical connection comprises a ball and an annular seat having an inner diameter for receiving the ball, with the second fluid channel formed between the ball and the annular seat. Here, the valve may include a control volume between the annular seat and a top surface of the piston body facing the magnetic pin.

[0016] In some implementations, the valve includes a control volume between the mechanical connection and a top surface of the piston body facing the magnetic pin. In this implementation, when (i) the first opening is aligned with the at least one supply port of the supply portion of the piston sleeve and (ii) actuation of the magnetic pin closes the second fluid channel, a volume of hydraulic fluid supplied from the hydraulic fluid supply source through the first fluid channel increases by the control volume. The reservoir portion of the piston sleeve may be closer to the mechanical connection than the supply portion of the piston sleeve.

[0017] The details of one or more implementations of the disclosure are set forth in the accompanying drawings and the description below. Other aspects, features, and advantages will be apparent from the description and drawings, as well as from the claims. DESCRIPTION OF DRAWINGS Fig. 1A and Fig. 1B are schematic views of an example of two-stage valves. Fig. Figure 2A is an exploded view of an example of a two-stage valve. Fig. 2B and Fig. 2C are perspective sectional views of an example of a two-stage valve from Fig. 2A along section line AA. Fig. 2D is a cross-sectional view of the example of the two-stage valve of Fig. 2A in deactivated state. Fig. 2E is a cross-sectional view of the example of a two-stage valve of Fig. 2A in a transition state. Fig. 2F is a cross-sectional view of the example of a two-stage valve of Fig. 2A in a pre-controlled state. Fig. 2G is a cross-sectional view of the example of a two-stage valve of Fig. 2A when activated.

[0018] Similar reference numerals in the various drawings indicate similar elements. DETAILED DESCRIPTION

[0019] Fig. 1A and Fig. 1B are examples of a hydraulic valve 100 (e.g., shown as a hydraulic schematic). Generally, the hydraulic valve 100 is implemented in a hydraulic system 10. A hydraulic system 10 typically includes components that perform fluid dynamic operations that can be controlled mechanically and / or electrically (e.g., by electrical signals). Here, the hydraulic system 10 includes a supply source 110, a tank 120, a control element 130, and an electrical input source 140.

[0020] In general, a supply source 110, such as a pump, is a mechanical component that generates fluid energy (i.e., fluid flow controlled by fluid velocity) by transferring mechanical energy to a fluid. For example, a motor shaft transmits torque to a pump shaft and generates fluid velocity. Hydraulic pumps can be hydrodynamic or hydrostatic. A hydrodynamic pump tends to lose capacity with increasing head pressure corresponding to the pump (e.g., due to fluid leakage and pressure drop when the pump is stopped). On the other hand, a hydrostatic pump typically moves a fixed volume of fluid from its inlet to its outlet regardless of the pressure at the outlet port.

[0021] Because hydraulic systems, such as hydraulic system 10, are closed systems, the system's hydraulic fluid is often stored and / or returned to a tank 120. Tank 120 generally refers to a low-pressure portion of hydraulic system 10 relative to an operating pressure of source 110. In other words, tank 120 may be an actual reservoir or an additional hydraulic circuit that operates at a lower pressure than the operating pressure. In some implementations, hydraulic system 10 includes more than one tank 120. For example, hydraulic system 10 may use a first tank at one pressure and a second tank at a second pressure that is different from the first pressure. In this case, hydraulic system 10 may use more than one tank 120 because different components may have different pressure requirements.In other words, connecting some components to the first tank 120 may cause pressure problems in the hydraulic system 10. For example, certain hydraulic components may require a lower pressure than the first tank 120 and thus require the second tank 120 (e.g., a pilot tank).

[0022] Typically, hydraulic system 10 controls the fluid dynamics (e.g., pressure or flow) through hydraulic valve 100 to actuate a control element 130. A control element 130 may, for example, refer to one or more hydraulic cylinders or a type of motor configured to perform work. To illustrate, if hydraulic system 10 corresponds to an industrial or agricultural hydraulic system, the one or more control elements 130 are hydraulic cylinders that perform the work to operate hydraulic attachments (e.g., front loaders, forks, plows, tillers, rotary tillers, etc.). Control element 130, as a hydraulic cylinder, may correspond to any type of cylinder that uses hydraulic fluid, such as a single-acting cylinder, a double-acting cylinder, a rodless cylinder, etc.

[0023] With reference to Fig. 1A and Fig. 1B, the valve 100 is a single hydraulic valve 100 that includes two stages, a first stage referred to as the pilot stage 200, and a second stage referred to as the main stage 300. A two-stage valve generally refers to a valve in which the functionality of two valves is combined (or integrated) into a single assembly. Integrating more than one valve into a single valve often involves structural challenges (e.g., flow / orifice challenges), size constraints (e.g., ensuring adequate clearances and surface areas to provide the required hydraulic forces or to distribute existing hydraulic forces), and / or other compatibility issues. Here, the two-stage valve 100 integrates a direct-acting proportional valve and a pilot-acting proportional valve.A proportional valve (also called a proportional spool valve) is used to control flow and / or pressure to a control element 130 by applying a driving force to move a spool against a restoring force. The restoring force can be a spring force, a hydraulic force (e.g., from the control element 130), or a combination of both. In some examples, solenoids, force motors, or indirect electromagnets are used to apply the force to the spool to ensure predictable movement between positions that overcomes the restoring force. Although proportional directional spool valves move through infinite positions between zero to one hundred percent of the valve's travel, proportional directional spool valves are often depicted schematically to illustrate the key or dominant functional positions that occur when the spool moves within the sleeve.For example, the . Fig. 1A and Fig. 1B schematic diagrams depicting the proportional spool valves with bars to the left and right of the valve to indicate that the proportional spool moves within a sleeve. The proportional spool valves for the first stage 200 and the second stage 300 have three positions (also called states) in the pilot stage 200 and three positions (also called states) in the main stage 300.

[0024] Without their integration into the two-stage hybrid valve 100 (also referred to simply as a two-stage valve 100), both the direct-acting proportional valve and the pilot-operated proportional valve have their individual disadvantages. For example, a direct-acting proportional valve typically uses an electromagnetic solenoid to directly drive the piston against the return force. As such, the architecture of the direct-acting proportional valve produces a relatively low drive force, making the direct-acting proportional valve design prone to failures, such as contamination-induced failures. Alternatively, a pilot-operated proportional valve also uses an electromagnetic solenoid, but with the solenoid actuating a valve poppet against a nozzle to control the hydraulic pilot pressure and drive the piston against the return force.Although a pilot-operated proportional valve can provide significantly greater force potential than a direct-acting proportional valve, the pilot-operated proportional valve still requires hydraulic fluid flow in the form of a pilot flow when the pilot-operated proportional valve is in a deactivated state. Because the pilot-operated proportional valve continues to require hydraulic fluid even in a deactivated state, the pilot-operated proportional valve is inherently inefficient in its use of hydraulic fluid.

[0025] In contrast, the two-stage valve 100 is capable of controlling a spool with both the electromagnetic force of a solenoid (as in a direct-acting proportional valve) and with additional hydraulic pressure (as in a pilot-operated proportional valve). With this approach, the two-stage valve 100 is able to utilize the large force potentials of the pilot-operated proportional valve while avoiding a continuous demand for hydraulic fluid in a deactivated state. The two-stage valve 100 can be used for various types of control between the source 110 and the control element 130. The two-stage valve 100 can be used as a flow control valve (e.g., without pressure feedback, as in Fig. 1A) or as a pressure control valve (e.g. with pressure feedback, as in Fig. 1B). The two-stage valve 100 can be configured as a three-way valve or a four-way valve, with each "way" corresponding to the port of the two-stage valve 100. For example, if the two-stage valve 100 is a three-way valve, the two-stage valve 100 includes three different types of ports, such as at least one supply port, at least one tank port, and at least one control port (also referred to as a work port). If the two-stage valve 100 is a four-way valve, the two-stage valve 100 includes four different types of ports, such as at least one supply port, at least one tank port, at least one first control port (e.g., for a first control element), and at least one second control port (e.g., for a second control element).Although these variations are possible, for simplicity, the operation of the two-stage valve 100 is described as a three-way valve and in particular in . Fig. 2A-2G shown and described as a three-way pressure control valve.

[0026] In Fig. 1A and Fig. 1B, the two-stage valve 100 includes the pilot stage 200 and the main stage 300. Here, the functionality of each stage 200, 300 functions similarly to (or can be depicted as) a three-position proportional spool valve. In the pilot stage 200, an electromagnet 210 receives an electrical signal from the electrical input source 140. The electrical input source 140 can be any type of regulator or controller configured to generate an electrical signal capable of energizing the electromagnet 210. When the electromagnet 210 is energized by such an electrical signal, the electromagnet 210 transitions the main stage 300 from a deactivated state (e.g., depicted as a first state S1 of the main stage 300) to a transient state (e.g., depicted as a second state S2 of the main stage 300) by moving a piston 310 (e.g., depicted in Fig. 2A-2G) of the main stage 300. In the first state S1 or in the deactivated state, hydraulic fluid is supplied between the control element 130 and the tank 120 based on a connection between a tank port P, P T and a control terminal P, Pc within the main stage 300. Also in the first state S1 is a supply terminal P, P S closed so that the source 110 does not supply hydraulic fluid to the control element 130 or a pilot line 302. To symbolize that the pilot line 302 does not receive hydraulic fluid, a control port P, P P the main stage 300 in the first state S1 is shown as a closed connection.

[0027] When the command to the solenoid 210 continues to increase (e.g., it receives a greater amount of current than the initial excitation current supplied by the electrical signal), the solenoid 210 actuates the piston 310 of the main stage 300 into the second state S2, in which hydraulic fluid begins to flow from the source 110 to the pilot line 302, based on a fluid connection between the supply port Ps and the control port P P . With the fluid connection between the supply port Ps and the pilot port P Pthe hydraulic pilot pressure can build up to a pressure level capable of actuating the piston of the main stage 300. Here, the pilot pressure generates a hydraulic force F against the piston 310, so that the actuation of the piston 310 transitions from the solenoid actuation to the pilot control. In other words, the hydraulic force F from the pilot pressure takes over the actuation of the piston 310 by the solenoid 210 and drives the piston 310 further into an activated state (e.g., shown as the third state S3). While the piston 310 is in the second state S2, the hydraulic fluid connection between the control element 130 and the tank 120 exists due to the fluid connection between the control port Pc and the tank port P Tcontinues, but this fluid connection begins to close when the piston 310 enters the third state S3 (ie, the activated state). In the activated state or the third state S3, the tank port P T closed and the source 110 supplies both the pilot line 302 (via the control terminal P P ) and the control element 130 (via the control connection Pc) with hydraulic fluid. With hydraulic fluid from the source 110, the control element 130 can perform a certain work (e.g., on hydraulic cylinders or a motor). Additionally or alternatively, Fig. 1B, when the two-stage valve 100 includes pressure feedback, the control element 130 and / or the control port Pc may include a pressure feedback line 304 that provides hydraulic fluid to assist the return force against the piston 310.

[0028] In some implementations, such as Fig. 1A and Fig. 1B, the pilot line 302 serves as an orifice for the hydraulic fluid. For example, the pilot line 302 has an opening or area that is smaller than the control port P P and / or the supply connection P S Due to the design of this smaller volume for the pilot line 302, the hydraulic fluid flowing through the pilot line 302 may have an increased flow rate and / or pressure. In other words, the two-stage valve 100 may be designed to control the pressure of the hydraulic fluid for the pilot line 302, which continues to drive the piston 310 to the activated state S3. In Fig. 1A and Fig. 1B, the concave lines around the pilot line 302 schematically denote a nozzle.

[0029] Since the piston 310 of the main stage 300 switches between the states S, the pilot-operated stage 200 can also function as a proportional valve that switches between the states S. As a three-position proportional valve, the Fig. 1A and Fig. 1B the pre-controlled stage 200 with three phases PH, PH 1-3 The pilot stage functions as a proportional valve by the way in which the magnetic pin 212 of the electromagnet 210 is commanded to move through a magnetic field by means of an electrical signal from the electrical input source 140. For example, as in Fig. 2A-2G, the magnetic pin 212 moves along a valve tube 218 in the pilot stage 200 and alternates the pilot stage 200 between PH, PH 1-3. As the pilot stage 200 transitions between phases PH, the pilot stage 200 is considered a two-way proportional valve because, in some configurations, the pilot stage 200 includes a first and a second path corresponding to a path through which the pilot hydraulic fluid flows through the pilot stage 200 of the two-stage valve 100. For example, Fig. 1A and Fig. 1B the path as a fluid connection from the pilot line 302 to the outlet line 202 and then to the tank 120. As in Fig. 2A-2G, the pilot hydraulic fluid flows from the pilot line 302 into a portion of the pilot-operated valve 200 and out a passageway (e.g., shown as channel 424) to the tank 120. In the first phase PH1 and the second phase PH2 of the pilot-operated valve 200, the pilot hydraulic fluid flows from the inlet of the passageway to the outlet of the passageway to the tank 120. In some examples, the difference between the first phase PH1 and the second phase PH2 is that the actuation of the solenoid 210 restricts or reduces the inlet of the passageway; this creates a jetting effect for the pilot hydraulic fluid as it flows from the inlet of the passageway to the outlet of the passageway in the second phase PH2 (e.g., compared to the first phase PH1 with no restriction of the inlet of the passageway).

[0030] In some configurations, the pilot stage 200 and the main stage 300 cooperate via a mechanical linkage 400. In this case, the mechanical linkage 400 couples the actuation of the electromagnet 210 (e.g., the magnetic pin 212) to the piston 310 of the main stage 300. With coupled actuation between the pilot stage 200 and the main stage 300, the PH phases of the pilot stage 200 can be linked or correspond to the S states of the main stage 300. When the main stage 300 transitions from a deactivated state (the first state S1) to the actuated state (the third state S3), the pilot stage 200 goes through three phases PH, PH 1-3. In other words, when the actuation of the piston 310 transitions from solenoid actuation to pilot control, the pilot-operated stage 300 can alternate between the three phases PH, corresponding to an open flow phase or first phase PH, PH1, a throttled flow phase or second phase PH, PH2, and a closed flow phase PH, PH3. For example, when the main stage 300 is in the second state S2 and the source 110 is supplying hydraulic fluid to the pilot line 302, the pilot-operated stage 200 can be in its first phase PH1. When the actuation of the piston 310 transitions from solenoid actuation to pilot hydraulic fluid control, the pilot-operated stage 200 can have shifted to the second phase PH2, in which the flow of the pilot hydraulic fluid is more restricted.As the main stage 300 transitions between the second state S2 and the third state S3, actuation of the piston 310 requires an increased amount of hydraulic force against the restoring force from the pilot hydraulic fluid. To meet this demand for increased hydraulic force, the pilot stage 200 may transition to the third phase PH3, preventing pilot hydraulic fluid from exiting through the passage to the outlet line 202. By preventing pilot hydraulic fluid from exiting the two-stage valve 100 through the outlet line 202, the pilot stage 200 ensures that the pilot hydraulic fluid remains within the two-stage valve 100 to provide sufficient force to drive the piston 310 to the actuated state (i.e., the third state S3) of the main stage 300.

[0031] Fig. 2A-2G are examples of a two-stage valve 100. In these examples, the pilot stage 200 includes the solenoid 210 and a housing assembly 220. In some implementations, the housing assembly 220 includes a main housing 222, a solenoid connector housing subassembly 224, and a coil housing 226. The solenoid connector subassembly 224 may further include a housing cap 224, 224a, a solenoid connector socket 224, 224b, a connector housing seal 224, 224c, and a solenoid pole 224d. The solenoid connector assembly 224 is generally configured to accept a mating connector plug into the connector socket 224b to make contact with terminals protruding from the coil housing 226.The mating connector may be wired to the electrical input source 140 and may transmit the electrical signal from the electrical input source 140 to energize the electromagnet 210. One or more components of the electromagnet connector subassembly 224 (e.g., the housing cap 224a or the housing seal 224c) may enable the connector connection and / or the electromagnet itself to be sealed / protected from environmental elements, such as contaminants or moisture.

[0032] As in Fig. 2A, the housing cap 224a refers to an outermost upper surface of the solenoid connector housing subassembly 224 that is at least partially wrapped around the portion of the connector receptacle 224b that protrudes from a top surface of the connector receptacle 224b. Here, the projection of the connector receptacle 224b is configured to receive a mating connector and at least partially enclose and / or seal any terminals or internal connections from potential damage. The connector housing seal 224c is another protective layer for the housing 220 that is configured to form a protective barrier for the internal components of the solenoid 210.Below the connector housing seal 224c, a series of metal windings, referred to as coils 214, are wound circumferentially around the coil housing 226 to generate a magnetic field along a central axis of the housing assembly 222. When the electrical input source 140 provides an electrical signal in the form of current to energize the electromagnet 210, the coils 214 generate a magnetic field.

[0033] An electromagnet 210 typically refers to a combination of an armature 216, the magnetic pin 212 (also called a plunger), and the coils 214. When an electrical current is applied to the electromagnet 210 (e.g., through the electrical input source 140), the coils 214 generate the magnetic field with a magnetic force capable of actuating the armature 216 into the magnetic pin 212; the magnetic pin 212 is displaced a distance within a magnetic chamber 218 (e.g., shown as a cylindrical valve tube surrounding the armature 216 and the magnetic pin 212 within the main housing 222). In the construction of the two-stage valve 100, the displacement of the magnetic pin 212 can drive the magnetic pin 212 toward or into the piston 310. Here, an actuation direction for the magnetic pin 212 refers to a direction that would push the piston 310 against the restoring force of the piston.In some configurations, the two-stage valve 100 is a cylindrical valve 100 in which the pilot stage 200 is disposed above the main stage 300 such that the magnetic pin 212 is urged downward (e.g., along a central axis of the valve 100) toward the piston 310.

[0034] Regarding the general construction of the pilot stage 200, the main housing 222 may be constructed to house the components of the solenoid 210 and at least a portion of the coil housing 226 to form the outer shell (i.e., the outer walls) for the pilot stage 200 of the two-stage valve 100. The connector housing subassembly 224 may be disposed on the coil housing 226 and / or the main housing 222 to enclose the solenoid 210 within the main housing 222. If the two-stage valve 100 is generally cylindrical, the components of the pilot stage 200 may be aligned along a central axis of the cylindrical shape. In other words, the main housing 222 together with the coil housing 226 has a hollow central chamber configured to surround the armature 216 and / or the magnet pin 212 by the magnetic field generated by the coils 214 (e.g.in the circumferential direction) and can move along the central axis based on the magnitude of the magnetic force generated by the magnetic field.

[0035] The main stage 300 generally includes the piston 310 and a piston sleeve 320. The piston 310 is configured to move along the inner walls of the piston sleeve 320 such that the piston 310 translates along a length of the piston sleeve 320 to move between the states S of the main stage 300. In some examples, the piston 310 includes a piston body 312 that has a generally cylindrical shape. The piston body 312 may include a control port portion 314 with an annular land that allows hydraulic fluid to be returned (e.g., to the tank 120) from or supplied to the control element 130 (e.g., from the source 110). For example, the annular land refers to a circumferential cutout along the body 312 of the piston 310, wherein the cutout of the body 312 (i.e.,The control port portion 314 has an outer diameter that is smaller than the average outer diameter of the entire body 312 of the piston 310. In some configurations, the annular land leads to at least one control port PC formed within a control port chamber 316 of the body 312 of the piston 310. For example, the piston body 312 includes a control port chamber 316 as a cavity within the piston body 312 along a central axis of the piston body 310. For illustrative purposes, . Fig. 2B-2G, the control port chamber 316 is defined as a cavity within the piston body 312 extending from a lower surface of the piston 310 opposite an upper surface of the piston body 310 facing the magnetic pin 212 along the central axis of the body 312.

[0036] In some configurations, the chamber 316 includes more than one control port PC corresponding to openings extending from the outer diameter for the body 312 at the control port portion 314 to the inner diameter of the body 312 forming the walls of the chamber 316. For example, the control ports PC are evenly spaced (e.g., evenly distributed) around a circumference of the body 312 of the piston body 310 in the control port portion 314 of the body 312. In some examples, the control port portion 314 is located near or at a midpoint along a length of the piston body 312.

[0037] In some configurations, the piston sleeve 320 is a cylindrical tube that encloses the body 312 of the piston 310. Here, an inner diameter for the walls of the piston sleeve 320 is substantially equal to the outer diameter of the piston body 312 to prevent significant hydraulic fluid from leaking between the piston sleeve 320 and the body 312 of the piston 310. For example, the walls of the piston sleeve 320 may define a hollow central cavity 322 that the body 312 of the piston 310 at least partially fills as it moves along the inner walls of the piston sleeve 320. As the body 312 of the piston 310 moves along the piston sleeve 320, the control port portion 314 of the body 312 may be aligned with a tank portion 324 of the piston sleeve 320, with a supply portion 326 of the piston sleeve 320, or with neither portion 324, 326.In some examples, due to the area of ​​the control port portion 314 and the distance between the tank portion 324 and the supply portion 326, it is not possible to align the control port portion 314 with both portions 324, 326 simultaneously. In other words, the two-stage valve 100 cannot have a configuration where hydraulic fluid is simply directed from the source 110 through the two-stage valve 100 into the tank 120. The tank portion 324 and the supply portion 326 of the piston sleeve 320 each refer to a region along the length of the piston sleeve 320 that either receives hydraulic fluid from the source 110 (i.e., the supply portion 326) or returns hydraulic fluid to the tank 120 (i.e., the tank portion 324).

[0038] In some examples, the tank portion 324 and the supply portion 326 are fluid-isolated by a seal 328, e.g., an O-ring seated in an annular groove around the circumference of the piston sleeve 320. For example, in Fig. 2B-2G illustrate three annular seals 328, 328a-c. The first annular seal 328a is located near the pilot stage 200 of the two-stage valve 100 and prevents the return hydraulic fluid to the tank 120 from leaking out of the tank section 324 (e.g., into an area surrounding the two-stage valve 100). The second annular seal 328b is located between the tank section 324 and the supply section 326 and prevents supplied hydraulic fluid from leaking into the tank section 324 (e.g., and reduces the pressure of the supplied hydraulic fluid) and / or prevents hydraulic fluid flowing back into the tank 120 from leaking into the supply section 326 (e.g., and also reduces the pressure of the supplied hydraulic fluid). The third ring seal 328c is located at one end of the two-stage valve 100 opposite the pilot stage 200.Here, this third ring seal 328c prevents the supplied hydraulic fluid from the source 110 from leaking (i.e., escaping) from the supply section 326 (e.g., into an environment around the two-stage valve 100).

[0039] Both the tank section 324 and the supply section 326 may each include one or more ports P that enable connection of the hydraulic fluid between the source 110, the tank 120, the control element 130 and / or the pilot line 302. In some examples, such as Fig. 2A-2G, each section 324, 326 contains a plurality of terminals P. For example, Fig. 2A, the ports P are evenly distributed around the circumference of the piston sleeve 320 in each section 324, 326. In some implementations, the ports P of the same type are coplanar and distributed around the circumference of the piston sleeve 320. In Fig. 2A are three tank connections P T1-3visible, while three supply connections P S1-3 are visible. By distributing the ports P along the circumference of the piston sleeve 320, the two-stage valve 100 can maintain stability and balance when subjected to the forces associated with the hydraulic fluid acting on the cylindrical shape. For example, the cross-sectional views of the Fig. 2B-2G that the ports P can be arranged symmetrically around the circumference of the piston sleeve 320.

[0040] In some configurations, the vertical distance (e.g., along the length of the piston sleeve 320) between a tank port P T and a supply connection P Sa distance that is greater than or equal to a length of the control port portion 314 of the body 312 of the piston 310. By having the distance between the ports P greater than the length of the control port portion 314, the geometry of the piston sleeve 320 relative to the body 312 allows the electronic signal and / or the hydraulic force F to select whether the control element 130 is fluidly connected to one of the sources 110 or the tank 120.

[0041] The piston body 312 also includes a pilot channel 318 as a pilot line 302 or as a part of the pilot line 302. For example, the Fig. 2B and Fig. 2C illustrates the pilot channel 318 as a channel drilled out of the body 312 of the piston 310 to allow the pilot hydraulic fluid to flow from the supply section 326 to a volume V (e.g., the volume shown in the Fig. 2B, 2C, and 2D-2G) above the body 312 of the piston 310 within the cavity 322 of the piston sleeve 320. For example, the pilot channel 318 is located between the outer diameter of the body 312 and the inner diameter forming the cavity 322. Based on the design of the two-way valve 100, an opening 318o of the pilot channel 318, which receives the hydraulic fluid from the source 110, may be in fluid communication with the supply portion 326 of the piston sleeve 320, but not with the tank portion 324 of the piston sleeve 320. In other words, in some examples, a length of the pilot channel 318 within the body 312 (e.g., the length extending from the top of the body 312 to the vicinity of the supply portion 326) is greater than the distance between a top of the body 312 and a tank port P TIn other words, the pilot channel 318 is not capable of fluidic communication with the tank port 120. Conversely, pilot hydraulic fluid directed through the pilot channel 318 can flow through at least a portion of the pilot-actuated stage 200 and exit to the tank 120 via the outlet conduit 202.

[0042] In some examples, the piston body 312 includes a shaft 312s. Here, the shaft 312s refers to a cylindrical rod that extends from a top surface of the piston body 312 (e.g., the surface facing the magnetic pin 212) toward the magnetic pin 212. In some applications, the magnetic pin 212 couples to the piston 310 by coupling to the shaft 312s of the body 312 of the piston 310. When the piston 310 couples to the magnetic pin 212 via the mechanical linkage 400, the shaft 312s may be the element of the piston 310 that couples to the mechanical linkage 400. In other words, the shaft 312s may receive the actuating force that moves the piston 310 along the piston sleeve 320.

[0043] In some configurations, the return force applied to the piston 310 is provided by one or more springs 330. In Fig. 2A-2G, for example, a first spring 330, 330a and a second spring 330, 330b jointly apply the restoring force to the piston 310. Each spring 330, which applies the restoring force, is positioned between the bottom surface of the spool 310 and the end (e.g., the end cap 340) of the two-stage valve 100 in the chamber cavity 322 of the piston sleeve 320. Additionally or alternatively, one or more of the springs 330 are disposed in the chamber 316 of the body 312. Regardless of the particular location, the restoring force refers to a force exerted on the piston 310 opposite its actuating direction. In some examples, the restoring force also positions the piston 310 in a default position. For example, the return force positions the piston 310 in the standard position when the two-stage valve 100 is in a deactivated state (e.g., the first state Si) in which the piston 310 does not apply a force that counteracts the return force.In some implementations, such as . Fig. 1B, a control line 304 from a control element 130 or a control port Pc supplies hydraulic fluid against the piston 310 instead of a spring return force or in addition to the spring return force (e.g. as in Fig. 1B).

[0044] In some configurations, a mechanical connection 400 exists between the pilot stage 200 and the main stage 300 such that the mechanical connection 400 is positioned as an intermediate link for coupling the magnetic pin 212 to the piston 310. In some examples, as shown in the Fig. 2A-2G, the mechanical linkage 400 includes a ball 410 and a ball chamber 420 in which the ball 410 is housed. Additionally, the ball chamber 420 may be defined as some form of restrictive element, including, for example, a ring seat 422 or other restrictive feature capable of decoupling the magnetic pin 212 and the piston 310 during operation of the valve 100. Here, the ball chamber 420 may be disposed or interposed between the main housing 222 of the pilot stage 200 and the piston sleeve 320 of the main stage 300. The ball chamber 420 may have a cavity along its central axis. In some examples, the width of the cavity is approximately equal to the diameter of the ball 410 and / or an outer diameter of the ring seat 422. When the ball chamber 420 is configured to include the seat 422, the ratio between the inner diameter of the seat 422 is smaller than the outer diameter of the ball 410.If the ball 410 is at least part of the mechanical linkage 400, the magnetic pin 212 is configured to drive the ball 410 into a restricting element and / or space and initially provide the driving force for the piston 310 (e.g., at the stem 312s of the piston 310). For example, the magnetic pin 212 is configured to drive the ball 410 into a portion of the ball chamber 420 (e.g., the seat 422 or a restricting portion of the chamber 420). However, as soon as the magnetic pin 212 drives the ball 410 completely into the throttle element (e.g., the seat 422), the pilot hydraulic fluid received from the channel 318 can no longer flow past the ball 410, resulting in an increased accumulation of hydraulic fluid from the pilot channel 318 (e.g., in a control volume V between the ball 410 and the top of the piston 310). By increasing the amount of hydraulic fluid above the piston body 312 (e.g.,in the control volume V), the force / pressure on the top side of the piston 310 from this hydraulic fluid is able to further drive the piston 310 in the direction of the restoring force into the actuated state S3. The locking element acts as a mechanical stop for the magnetic pin 212. For example, the annular seat 422 acts as a mechanical stop for the magnetic pin 212, so that the ball 410 seated in the annular seat 422 prevents the magnetic pin 212 from further actuating the piston 310. In other words, even if a current causes the magnetic pin 212 to exert more force on the ball 410, the annular seat 422 prevents the ball 410 from traveling any further, and the magnetic pin 212 is unable to further actuate the piston 310.Although the figures illustrate the limiting element as an annular seat 422 within the ball chamber 420, the limiting element may refer to any element that prevents the magnetic pin 212 from further actuating the piston 310 by limiting the travel of the magnetic pin.

[0045] In some examples, the ball chamber 420 includes at least one fluid passage 424. In these examples, the fluid passage 424 connects the outlet conduit 202 to the pilot passage 318 (i.e., the pilot conduit 302). In some applications, the fluid passage 424 connects the outlet conduit 202 to the pilot passage 318 at the bottom of the main housing 222, where the magnetic pin 212 would contact the piston 310.

[0046] Fig. 2B and Fig. 2C illustrate the flow path for the pilot hydraulic fluid (e.g., the flow path is shown in arrows). When the magnet 210 is energized so that the piston body 312 moves to a position in which a first opening 318o, 318o1 of the pilot channel 318 is connected to a supply port P S the piston sleeve 320 is aligned, shows Fig. 2B, that the pilot hydraulic fluid flows through the channel 318, which is smaller than the supply port P Sand flows from a second opening 318o, 318o2 of the pilot channel 318 into the cavity 322 above the top of the piston 310. Here, the shaft 312s of the piston 310 has a smaller diameter than the inner diameter of the annular seat 422. Because the shaft 312s has a smaller diameter, the pilot hydraulic fluid can flow between the shaft 312s and the hollow inside of the annular seat 422, so that the flow path also includes the volume between the shaft 312s and the annular seat 422. In Fig. 2B, the ball 410 is not fully pressed against the annular seat 422, therefore the pilot hydraulic fluid can continue to flow between the ball 410 and the annular seat 422, exit the fluid channel 424 of the ball chamber 420, and continue to the outlet line 202 connected to the tank 120. Therefore, the flow path for the pilot hydraulic fluid can include the pilot channel 318, the volume between the mechanical connection 400 (e.g., a first volume between the stem 312s and the annular seat 422 in combination with a second volume between the ball 410 and the annular seat 422), the fluid channel 424, and the outlet line 202 connected to the fluid channel 424. Referring to Fig. 2B, the fluid channel 424 extends through the wall of the ball chamber 420 and the outlet line 202 extends through the wall of the piston sleeve 320 (e.g., to the tank portion 324 of the piston sleeve 320).

[0047] Fig. 2C, in contrast to Fig. 2B does not focus entirely on the flow path for the pilot hydraulic fluid, but rather on the pressure generated by the pilot hydraulic fluid. For example, when solenoid 210 is energized, the pilot hydraulic fluid continues to build pressure against ball 410 as well as against the top of piston body 312. Furthermore, this figure shows that a fully seated ball 410 (i.e., a ball 410 pressed into the inner diameter of ring 422) prevents the pilot hydraulic fluid from entering channel 424 and causing greater pressure / force on the piston itself in the direction of the restoring force. In this scenario, the greater pressure / force is then used to further actuate piston 310 along piston sleeve 320 to actuated location S3.

[0048] Fig. Figures 2D-2G are examples of the two-stage valve 100 transitioning between states S and / or phases PH, and the hydraulic flow accompanying these states / phases. To illustrate the hydraulic flow, the hydraulic fluid from source 110 is shown as solid black arrows, while the hydraulic fluid flowing back to tank 120 is shown as hatched arrows. Fig. 2D, the two-stage valve 100 is in a deactivated state (e.g. the first state S1 of the Fig. 1A and Fig. 1B). In a deactivated state, the electromagnet 210 has not received an electrical signal that energizes the electromagnet 210. In this deactivated state, the magnetic pin 212 is retracted from the piston 310 because no actuating force is exerted on the magnetic pin 212 by a magnetic field from the coils 214. However, in some examples, the magnetic pin 212 is in contact with the ball 410, which in turn is in contact with the piston 310 (e.g., the stem 312s of the piston body 312). Here, without energization of the electromagnet 210, the energy to generate the magnetic field is not available. Starting from this deactivated state, in which both the magnetic pin 212 is coupled to the ball 410 and the shaft 312s of the piston body 310 is also coupled to the ball 410, any force subsequently mechanically exerted by the magnetic pin 212 on the ball 410 can be equal to the force generated by the magnetic pin 212.With respect to the main stage 300, in the deactivated state, the piston 310 is fully retracted toward the magnetic pin 212 to a position based on the restoring force of the spring(s) 330. Here, the retracted position is illustrated as the top of the body 312 of the piston 310 in contact with a bottom of the ball chamber 420. As for the first state S1 for the main stage 300 in FIG. Fig. 1A and Fig. 1B, in the deactivated state the supply connection(s) P S blocked / closed and there is a fluid connection between the control element 130 and the tank 120. Accordingly, the pilot channel 318 is also physically blocked and prevents unwanted pilot hydraulic fluid from flowing into any part of the two-stage valve 100 in this state S1. Fig. 2D, this means that the control port portion 314 of the body 312 of the piston 310 is not aligned with the supply portion 326, but is partially aligned (i.e., partially open) with the tank portion 324. Due to this partial alignment, hydraulic fluid from the control element 130 can be discharged via a fluid connection between the control port Pc and the tank port P T flow back into tank 120.

[0049] In Fig. 2E, the pilot stage 200 receives a command (e.g. an electrical signal) that excites the electromagnet 210 and transfers the piston 310 into the flow phase PH1 of the transition state S2 (e.g. in Fig. 1A and Fig. 1B as the first phase PH1 for the second state S2). Based on this command, the solenoid pin 212 is partially extended while in contact with the ball 410. By partially extending the solenoid pin 212 (which is also in contact with the ball 410), the solenoid pin 212 moves the stem 312s of the piston 310 (and the piston 310) proportional to the extension of the solenoid pin. With this initial coupling between the solenoid pin 210, the ball 410, and the piston 310 (e.g., the stem 312s of the piston 310), the two-stage valve 100 functions similarly to a direct-acting proportional valve, since the force mechanically applied by the solenoid pin 212 is transmitted through the ball 410 directly to the piston 310. In this case, the clutch moves the piston 310 a distance along the piston sleeve 320 that is approximately equal to the distance traveled by the magnetic pin 212.In this flow phase PH1 of the transition state S2, the opening 318o for the channel 318 within the body 312 of the piston 310 is aligned with the supply portion 326 of the piston sleeve 320. With this alignment, the pilot channel 318 receives hydraulic fluid from the source 110, and the channel 318 transfers the pilot hydraulic fluid into the chamber cavity 322 of the piston sleeve 320 above the top of the body 312. Since the ball 410 is not fully seated in the seat 422 here, the pilot hydraulic fluid flows from the passage 318 between the stem 312s and the annular seat 422, then between the ball 410 and the seat 422, and through a combination of the channel 424 in the ball chamber 420 and the outlet line 202 to the tank 120.During this phase PH1 of transition state S2, the hydraulic force exerted on the top of piston 310 is negligible or minimal because the gap between ball 410 and seat 422 is large enough to prevent the buildup of significant hydraulic control pressure in chamber cavity 322. As piston 310 moves toward transition state S2 (i.e., the state where the valve transitions from solenoid to pilot control), the total force exerted on piston 310 is nearly equal to the force exerted on piston 310 by solenoid 210. Furthermore, in this phase PH1 of the transition state S2, the position of the body 312 of the piston 310 still coincides with a part of the control connection section 314 of the body 312 of the piston 310 with the tank section 324 of the piston sleeve 320 and not with the supply section 326 of the piston sleeve 320.With this orientation to the tank portion 324, a portion of the hydraulic fluid from the control element 130 can be supplied via a fluid connection between the control port Pc and the tank port P. T flow back into tank 120.

[0050] Referring to Fig. 2F, the two-stage valve 100 enters a modulation phase (or throttling phase PH2) of the transition state S2 when the solenoid 210 receives another command (e.g., receives more current from an electrical signal from the electrical input source 140). Here, the modulation phase PH2 appears similar to that in Fig. 2E, but a slight extension of the magnetic pin 212 has driven the ball 410 further toward the seat 422, so that although the pilot hydraulic fluid can still flow from the pilot passage 318 to the fluid channel 424 in the ball chamber 420 and out the outlet line 202, the pilot hydraulic fluid begins to build up a significant hydraulic force F against the top of the body 312 of the piston 310 in the chamber cavity 322 of the piston sleeve 320 (e.g., as shown by the arrows on the top of the piston body 312). In this modulation phase PH2, the lower surface of the ball 410 receives pressure from the hydraulic force F. Here, the hydraulic force F on the lower surface of the ball 410 is part of an equilibrium condition with the force exerted on the ball 410 by the magnetic pin 212. In this case, the hydraulic force F exerted on the piston 310 may be directly proportional to the force exerted by the magnetic pin 212.For example, the force exerted on piston 310 can be represented by the following equation:. FPiston,main≅APiss,mainASeat,ID(FElectromagnet) where A Kolben,Haupt the surface of the top of the body 312 of the piston 310, A Sitz,ID is the area of ​​the seat 422 based on the inner diameter of the seat 422, and F Elektromagnet is the force applied by the magnetic pin 212.

[0051] In some examples, with the significant buildup of pilot hydraulic fluid pressure due to the reduced gap between ball 410 and seat 422, the hydraulic force F applied to piston 310 will further move body 312 of piston 310, thus uncoupling stem 312s of piston 310 from its coupling with mechanical linkage 400 (e.g., ball 410). Once this uncoupling occurs, magnetic pin 212 can no longer exert an actuating force on body 312 of piston 310, and hydraulic force F will control the movement of piston 310. In modulation phase PH2, the position of body 312 of piston 310 may still align a small portion of control port portion 314 with reservoir portion 324 of piston sleeve 320, but not with supply portion 326 of piston sleeve 320.At this small fraction of the alignment to the tank portion 324, the hydraulic fluid from the control element 130 can be supplied via the fluid connection between the control port Pc and the tank port P. T still flow back into tank 120.

[0052] In Fig. 2G, the piston 310 has entered the fully actuated state (e.g. the third state S3 of the main stage 300 and the third phase PH3, or closed flow phase, of the pilot-controlled stage 200 from Fig. 1A and Fig.1B). In the fully actuated state, the solenoid 210 has been driven to its maximum state by the electrical input source 140. Here, the solenoid pin 212 has driven the ball 410 fully into the seat 422, closing the passage 424 to the outlet line 202 to the tank 120. For example, the flow arrows corresponding to the flow of pilot hydraulic fluid are no longer indicated as a passage between the ball 410 and the seat 422. In this state, the source 110 supplies hydraulic fluid to the control line 318. Without venting or relieving the pilot hydraulic pressure to the tank 120 (e.g., via the passage 424 and the outlet line 202), the hydraulic force F from the pilot hydraulic fluid in the chamber cavity is responsible for all the force on the piston 310.When the piston 310 is moved to this fully actuated state, the control port portion 314 of the body 312 of the piston 310 aligns with the supply port 326 of the piston sleeve 320. Due to this alignment, the source 110 is able to fluidly connect the control element 130 to the supply port P. S and the control port Pc with hydraulic fluid.

Claims

[1] A valve (100) comprising: an excitable electromagnet (210) having a magnetic chamber (218) in which a magnetic pin (212) is housed; a proportional piston (310) with a piston body (312) and a piston sleeve (320), wherein the piston sleeve (320) receives the piston body (312) and has a supply section (326) with at least one supply connection (P, Ps) in fluid communication with a hydraulic fluid supply source (110) and a tank section (324) with at least one tank connection (P, P T) in fluid communication with a reservoir (120) for the hydraulic fluid, wherein the piston body (312) has a first fluid channel (318) extending from a first opening (318o1) to a second opening (318o2), and wherein the first opening (318o1) of the piston sleeve (320) and the second opening (318o2) face the magnetic pin (212), and wherein the first opening (318o1) is not able to enter into fluid communication with the tank portion (324) of the piston sleeve (320); a mechanical connection (400) coupling the magnetic pin (212) to the piston body (312), and wherein the mechanical connection (400) at least partially comprises a second fluid channel (202, 424) extending through the piston sleeve (320) to the tank portion (324); and a flow path (202, 424, 318) for hydraulic fluid from the supply source (110), the flow path (202, 424, 318) comprising the first fluid channel (318) and the second fluid channel (202, 424), and wherein, when the excitable electromagnet (210) is de-energized, the first opening (318o1) of the first fluid channel (318) is not connected to the at least one supply connection (P, P S ) of the supply section (326). [2] Valve (100) according to claim 1, wherein the piston body (312) has at least one working port (P, Pc) along a central axis of the piston body (312). [3] The valve (100) of claim 2, wherein the piston body (312) includes a chamber (316) along the central axis of the piston body (312), and wherein the chamber (316) includes the at least one working port (P, Pc) configured to be selectively connected between the at least one supply port (P, Ps) of the supply section (326) and the at least one tank port (P, P T ) of the tank section (324). [4] Valve (100) according to one of claims 2 or 3, wherein the piston body (312) has an upper surface facing the magnetic pin (212), and wherein, when the electromagnet (210) is energized and the first opening (318o1) for the first fluid channel (318) in the piston body (312) is aligned with the at least one supply port (P, Ps) of the supply section (326), the hydraulic fluid from the supply source (110) exerts a force (F) on the piston body (312) against the upper surface of the piston body (312). [5] The valve (100) according to any one of claims 1-4, wherein the mechanical connection (400) comprises a flow-throttling element. [6] Valve (100) according to any one of claims 1-5, wherein the mechanical connection (400) further comprises a ball (410) and an annular seat (422) having an inner diameter for receiving the ball (410), and wherein the second fluid channel (202, 424) is formed between the ball (410) and the annular seat (422). [7] The valve (100) of claim 6, further comprising a control volume (V) between the annular seat (422) and an upper surface of the piston body (312) facing the magnetic pin (212). [8] Valve (100) according to one of claims 1-6, further comprising a control volume (V) between the mechanical connection (400) and an upper side of the piston body (312) facing the magnetic pin (212), and wherein, when (i) the first opening (318o1) is connected to the at least one supply opening (P, P S ) of the supply section (326) of the piston sleeve (320) and (ii) the actuation of the magnetic pin (212) closes the second fluid channel (202, 424), a volume of the hydraulic fluid supplied from the hydraulic fluid supply source (110) through the first fluid channel (318) increases in the control volume (V). [9] Valve (100) according to any one of claims 1-8, wherein the tank portion (324) of the piston sleeve (320) is closer to the mechanical connection (400) than the supply portion (326) of the piston sleeve (320). [10] The valve (100) of any one of claims 1-9, wherein the tank portion (324) of the piston sleeve (320) is located at a location closest to the electromagnet (210), and the first fluid channel (318) extends along a length of the piston body (312) from a top surface of the piston body (312), and wherein a length of the first fluid channel (318) is greater than a length of the tank portion (324) of the piston sleeve (320). [11] A valve (100) comprising: a pilot-operated stage (200) having an electromagnet (210), wherein the electromagnet (210) has a magnet chamber (218) in which a magnet pin (212) is housed, and wherein, when the electromagnet (210) is energized, the electromagnet (210) actuates the magnet pin (212); and a main stage (300) with a proportional piston (310) which is accommodated in a piston sleeve (320), wherein the piston sleeve (320) has a supply section (326) with at least one supply connection (P, P S ) in fluid communication with a hydraulic fluid supply source (110) and a tank section (324) with at least one tank connection (P, P T ) in fluid communication with a reservoir (120) for the hydraulic fluid, wherein the proportional piston (310) has a piston body (312) with a first fluid channel (318) which receives hydraulic fluid from the supply source (110) when a first opening (318o1) for the first fluid channel (318) in the piston body (312) is aligned with the at least one supply opening (P, Ps) of the supply section (326), wherein, when the electromagnet (210) is energized and the first opening (318o1) for the first fluid channel (318) in the piston body (312) is connected to the at least one supply opening (P, P S ) of the supply section (326), hydraulic fluid from the supply source (110) (i) exerts a force (F) on the piston body (312) in an actuating direction by the magnetic pin (212) and (ii) flows to a second fluid channel (202, 424) within the pilot-operated stage (200) of the valve (100), and wherein the second fluid channel (202, 424) is in fluid communication with the reservoir (120) for the hydraulic fluid. [12] Valve (100) according to claim 11, wherein the piston body (312) has at least one working port (P, Pc) along a central axis of the piston body (312). [13] Valve (100) according to claim 12, wherein the piston body (312) has a chamber (316) along the central axis of the piston body (312), and wherein the chamber (316) has the at least one working port (P, Pc) configured to be selectively connected between the at least one supply port (P, Ps) of the supply section (326) and the at least one tank port (P, P T ) of the tank section (324). [14] Valve (100) according to one of claims 12 or 13, wherein the piston body (312) has an upper surface facing the magnetic pin (212), and wherein when the electromagnet (210) is energized and the first opening (318o1) for the first fluid channel (318) in the piston body (312) is connected to the at least one supply opening (P, P S) of the supply section (326), hydraulic fluid from the supply source (110) exerts the force (F) on the piston body (312) against the upper surface of the piston body (312). [15] The valve (100) of any of claims 11-14, further comprising a mechanical connection (400) between the pilot stage (200) and the main stage (300), and wherein actuation of the magnetic pin (212) couples the magnetic pin (212) to the mechanical connection (400) to move the piston body (312) within the piston sleeve (320). [16] Valve (100) according to claim 15, wherein the piston body (312) moves within the piston sleeve (320) in a first state (S, S1) and a second state (S, S2) in the actuating direction, wherein during the first state (S, S1) the actuation of the magnetic pin (212) drives the mechanical connection (400) into the piston body (312), which moves the piston body (312) into a first position, and wherein during the second state (S, S2) the piston body (312) is decoupled from the mechanical connection (400) and the force (F) exerted on the piston body (312) by the hydraulic fluid flowing through the first fluid channel (318) moves the piston body (312) along the piston sleeve (320) from the first position to a second position further away from the mechanical connection (400). [17] Valve (100) according to one of claims 15 or 16, wherein the mechanical connection (400) comprises a flow-limiting element. [18] The valve (100) of claim 17, wherein the flow-limiting element comprises a ball (410) and an annular seat (422) for the ball (410). [19] The valve (100) of claim 18, wherein the piston body (312) includes a connecting rod having a diameter smaller than the inner diameter of the annular seat (422) for the ball, and wherein, during the first state (S, S1) and the second state (S, S2), hydraulic fluid flowing through the first fluid channel (318) of the piston body (312) is in fluid communication with the second fluid channel (202, 424) along a fluid path between the connecting rod and the annular seat (422), and wherein the hydraulic fluid exerts a corresponding force on the ball (410) to allow the hydraulic fluid to flow between the annular seat (422) and the ball (410) to the second fluid channel (202, 424). [20] Valve (100) according to one of claims 18 or 19, further comprising a ball chamber (420) in which the ball (410) and the annular seat (422) for the ball (410) are housed, and wherein the ball chamber (420) has at least one opening (424) at least partially defining the second fluid channel (202, 424). [21] The valve (100) of any of claims 11-20, wherein the tank portion (324) of the piston sleeve (320) is located at a location closest to the electromagnet (210), and the first passage (318) extends along a length of the piston body (312) from a top surface of the piston body (312), and wherein a length of the first passage (318) is greater than a length of the tank portion (324) of the piston sleeve (320). [22] A main stage (300) of a two-stage valve (100) comprising: a piston body (312) with a control fluid channel (318); and a piston sleeve (320) receiving the piston body (312) and comprising: a supply section (326) with at least one supply connection (P, P S ) in fluid communication with a hydraulic fluid supply source (110) and a tank section (324) with at least one tank connection (P, P T ) in fluid communication with a reservoir (120) for the hydraulic fluid, wherein a first opening (318o1) of the control fluid channel (318) is unable to be in fluid communication with the tank portion (324) of the piston sleeve (320), and, when the main stage (300) is deactivated, the first opening (318o1) of the control fluid channel (318) in the piston body (312) is blocked from receiving hydraulic fluid from the hydraulic fluid supply source (110), and wherein, when the first opening (318o1) of the control fluid channel (318) in the piston body (312) is aligned with the at least one supply opening (P, Ps) of the supply section (326), hydraulic fluid flows from the supply source (110) through the control fluid channel (318) to exert a driving force (F) on the piston body (312) to move the piston body (312) along a length of the piston sleeve (320) in an actuating direction against a restoring force. [23] The main stage (300) of the two-stage valve (100) according to claim 22, wherein the piston body (312) has at least one working port (P, Pc) along a central axis of the piston body (312). [24] The main stage (300) of the two-stage valve (100) of claim 23, wherein the piston body (312) includes a chamber (316) along the central axis of the piston body, and wherein the chamber (316) includes the at least one working port (P, Pc) configured to be selectively connected between the at least one supply port (P, P S ) of the supply section (326) and the at least one tank connection (P, P T ) of the tank section (120). [25] The main stage (300) of the two-stage valve (100) according to any one of claims 22-24, wherein the piston body (312) has a lower surface configured to receive the restoring force and an upper surface opposite the lower surface, and wherein, as the piston body (312) moves along the length of the piston sleeve (320), a control volume (322, V) within the piston sleeve (320) increases in volume (V) above the upper surface of the piston body (312). [26] The main stage (300) of the two-stage valve (100) according to claim 25, wherein the drive force (F) applied by the hydraulic fluid from the control fluid channel (318) increases proportionally to an increase in the control volume (322, V) above the top of the piston body (312). [27] The main stage (300) of the two-stage valve (100) according to any one of claims 22-26, wherein: the piston body (312) includes a lower surface configured to receive the restoring force and an upper surface opposite the lower surface; the piston body (312) has a chamber (316) along a central axis of the piston body (312), the chamber (316) having the at least one working port (P, Pc) configured to be selectively connected between the at least one supply port (P, Ps) of the supply section (326) and the at least one tank port (P, P T ) of the tank section (324); and the first opening (318o1) for the control fluid channel (318) is arranged at a position along a length of the piston body (312) closer to the bottom surface of the piston body (312) than the at least one working opening (P, Pc). [28] The main stage (300) of the two-stage valve (100) according to any one of claims 22-27, wherein: the piston body (312) has a lower surface configured to receive the restoring force and an upper surface opposite the lower surface; the piston body (312) has a chamber (316) along a central axis of the piston body (312), the chamber (316) having the at least one working port (P, Pc) configured to be selectively connected between the at least one supply port (P, Ps) of the supply section (326) and the at least one tank port (P, P T ) of the tank section (324); and a first distance between the at least one working port (P, Pc) and the upper surface is smaller than a second distance between the first opening (318o1) for the passage of the control fluid channel (318) and the upper surface. [29] The main stage (300) of the two-stage valve (100) according to any one of claims 22-28, wherein, when the first opening (318o1) of the control fluid channel (318) in the piston body (312) is aligned with the at least one supply port (P, Ps) of the supply section (326), a first portion of the hydraulic fluid flows from the supply source (110) through the control fluid channel (318) to apply the driving force (F) to the piston body (312), and a second portion of the hydraulic fluid flows from the supply source (110) through the control fluid channel (318) and out of the piston sleeve (320) to the reservoir (120). [30] The main stage (300) of the two-stage valve (100) according to claim 29, wherein: the piston body (312) has a lower surface configured to receive the restoring force and an upper surface opposite the lower surface, and when the piston body (312) moves along the length of the piston sleeve (320), a control volume (322, V) within the piston sleeve (320) increases in volume (V) above the upper surface of the piston body (312) and in response to the increase in the volume (V) above the upper surface of the piston body (312), the volume of the second portion of hydraulic fluid from the supply source (110) flowing through the control fluid channel (318) and out of the piston sleeve (320) to the reservoir (120) decreases. [31] The main stage (300) of the two-stage valve (100) according to any one of claims 22-30, wherein: an activated position for the piston body (312) corresponds to a position in which at least one working connection (P, Pc) in the piston body (312) is connected to the at least one supply opening (P, P S ) of the supply section (110); and when the piston body (312) moves along the length of the piston sleeve (320) in the actuation direction to the activated position, the first opening (318o1) of the control fluid channel (318) is aligned with the at least one supply connection (P, Ps) of the supply section (326) before the at least one working connection (P, Pc) is aligned with the at least one supply connection (P, P S ) of the supply section (326).

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