Valve device and electrohydraulic steering system

Abstract

The invention relates to a valve device (100) having at least one housing body (110), which comprises at least one main chamber (120), and at least one slide unit (130). The slide unit (130) is movably positioned within the main chamber (120) of the housing body (110) and divides the main chamber (120) into a first compartment (122) and a second compartment (124). The at least one slide unit (130) is provided as a pressure-compensated slide unit (130) and is designed such that an at least substantially equal fluid pressure prevails within the main chamber (120) in the first compartment (122) and in the second compartment (124). The invention also relates to an electrohydraulic steering system and to a vehicle.

Description

[0001] DESCRIPTION

[0002] Valve assembly and electro-hydraulic steering system

[0003] The present invention relates to a valve assembly and an electro-hydraulic steering system for a vehicle, in particular a commercial vehicle. Furthermore, the present invention relates to a vehicle, in particular a commercial vehicle, with such a valve assembly and / or such an electro-hydraulic steering system.

[0004] In principle, various types and designs of valve devices are known from the state of the art.

[0005] However, it has been shown that the pressure conditions within these valve devices only allow a limited range of use and result in increased leakage and increased wear of the valve device.

[0006] Known valve devices only allow adjustment or the setting of a new position in the sense of a valve switching process against an internal fluid pressure. Therefore, the actuation speed of the respective valve device is also limited.

[0007] During rapid steering maneuvers, such as quick evasive maneuvers, a vehicle equipped with such a valve in an associated electro-hydraulic steering system may experience a drop or decrease in operating pressure in the steering system's piston chamber, particularly at low temperatures. This behavior can slow down an electro-hydraulic steering system and / or impair steering response in general.

[0008] Thus, under certain circumstances, a driver might not receive the necessary hydraulic power steering assistance from the steering system in a timely manner. Furthermore, this operating behavior could negatively affect the driver's steering feel. The object of the present invention is to provide a valve device that is cost-effective, efficient, and requires little maintenance, occupies a small installation space, offers improved system dynamics and / or response, and is flexibly designed. The invention also aims to provide an electro-hydraulic steering system and a vehicle.

[0009] This problem is solved according to the invention by a valve device according to independent claim 1, with regard to the electro-hydraulic steering system by the subject matter according to claim 13 and with regard to the vehicle by the subject matter of claim 15.

[0010] According to the present invention, a valve assembly, particularly for an electro-hydraulic steering system of a vehicle, is provided with at least one housing body having at least one main chamber and at least one slide unit, wherein the slide unit is movably arranged within the main chamber of the housing body, preferably translationally displaceable. The slide unit divides the main chamber into a first section and a second section, wherein the at least one slide unit is designed as a pressure-balanced slide unit and is configured such that at least substantially the same fluid pressure is present in the first section and in the second section, in particular pressure equalization between the first section and the second section is provided via the at least one slide unit.

[0011] The present invention is based on the basic idea that pressure equalization within the main chamber, i.e. between the first section and the second section, results in a lower load on the valve element or valve unit, and thus reduces leakage and wear of the valve assembly.

[0012] Furthermore, a pressure-balanced design of the valve assembly allows for more dynamic and faster adjustment of the slide unit within the main chamber. The movable slide unit must, at least primarily, only be moved against mechanical resistances such as frictional forces to achieve a new position of the valve assembly.

[0013] Therefore, venting a (pressure) connection, for example into a hydraulic tank, or connecting or separating two (pressure) connections can be carried out advantageously.

[0014] For the purposes of the present invention, the translational displaceability or mobility of the slide unit is understood to mean, in particular, that the slide unit is displaceable within the housing body. In particular, the valve assembly or the housing body may have a longitudinal axis so that the slide unit is arranged to be displaceable or movable in the longitudinal direction.

[0015] The slide unit divides the main chamber into a first section and a second section. The slide unit is therefore positioned within the main chamber in such a way that the volumes of the first and second sections can be changed based on the movement of the slide unit.

[0016] The slide valve unit or valve assembly can be designed as a unidirectional valve assembly or as a bidirectional valve assembly.

[0017] According to the present invention, the at least one slide unit is designed as a pressure-balanced slide unit. For this purpose, the slide unit is configured such that the fluid pressure in the first section and the second section is at least substantially the same. Preferably, pressure equalization between the first section and the second section can be provided via or by means of the at least one slide unit, in particular by means of the design of the at least one slide unit.

[0018] In the context of the present invention, the pressure-balanced design of the valve unit can preferably be understood to mean that a hydraulic short-circuit connection is provided between the first section and the second section of the main chamber via the valve unit. Accordingly, there is no hydraulic separation between the first and second sections by means of the valve unit.

[0019] Furthermore, the functionality of the valve assembly can be changed or determined based on the pressure-balanced slide unit or the positioning position of the pressure-balanced slide unit within the main chamber, among other things to bring about a hydraulic separation or connection between ports of the valve assembly.

[0020] The present invention provides a low-maintenance, efficient, and in particular efficiently adjustable, as well as dynamically adjustable valve device.

[0021] In a preferred embodiment, the slide unit, in particular a cover element of the slide unit, has at least one through-opening so that a fluid connection between the first section and the second section of the main chamber is provided or can be provided.

[0022] In particular, a hydraulic fluid, such as oil, can flow from the first or second section to the second or first section along a pressure differential across the passage opening of the slide assembly. Preferably, pressure equalization of the oil or hydraulic fluid within the main chamber, i.e., between the first and second sections, can occur across the slide assembly.

[0023] For the purposes of the present invention, a passage opening can be understood to be a bore, a fluid channel, or the like. Further elements such as throttling elements, filter elements, or the like can be provided within the passage opening.

[0024] The through-hole of the valve assembly allows for the (temporary) fluid connection between the first and second sections of the main chamber, enabling pressure equalization or a pressure-balanced valve assembly. A displacement or change in the position of the valve assembly should preferably only occur against mechanical resistance forces, such as internal frictional forces of the valve assembly, but in particular not against a pressure difference between the first and second sections of the main chamber.

[0025] According to a further preferred embodiment, the valve device has at least one sleeve element which is arranged inside the housing body, in particular is arranged immovably, wherein an inner side of the sleeve element and an outer side of the movable slide unit are provided to interact, in particular to form a sealing or fluid-tight sliding connection section by section.

[0026] According to the present invention, a fluid-tight connection of different ports of the valve assembly can be achieved by means of the interaction of at least one section of the outer surface of the slide unit and at least one section of the inner surface of the sleeve element. In particular, ports can be separated from one another by means of the interacting surfaces, or a fluid connection can be provided between ports in the valve direction as required.

[0027] In a preferred embodiment, the housing body has at least one first connection, wherein the sleeve element has at least one first connection opening, wherein the first connection opening along the sleeve element is designed to correspond to the first connection of the housing body, so that a fluid connection between the main chamber and the first connection of the housing body can be provided as required, in particular depending on a positioning position of the movable slide unit relative to the sleeve element.

[0028] In a preferred embodiment, the housing body has at least one second connection, wherein the sleeve element has at least one second connection opening. The second connection opening is configured along the sleeve element corresponding to the second connection of the housing body, such that a fluid connection between the main chamber and the second connection of the housing body can be provided as needed, in particular depending on the position of the movable slide unit relative to the sleeve element.

[0029] According to a further embodiment, the housing body has at least one third connection, wherein the third connection is designed along the housing body in such a way that a fluid connection to the main chamber is provided regardless of the position of the movable slide unit.

[0030] In a further preferred embodiment, the slide unit is designed and movable in such a way, in particular the outside of the slide unit is provided to interact section by section with the inside of the sleeve element, such that depending on a positioning position of the slide unit

[0031] - a fluid connection can be provided between the first port and the second port of the housing body,

[0032] - a fluid connection can be provided between the first port and the third port of the housing body,

[0033] - a fluid connection between the second port and the third port of the housing body can be provided and / or

[0034] - a fluid connection between the first, second and / or third connection of the housing body is separable.

[0035] In particular, it is provided that a fluid connection between the main chamber and at least one connection of the housing body can be provided via at least one connection opening of the sleeve element.

[0036] It is thus provided that a fluid connection to the main chamber, in particular for a first connection and a second connection, can be provided or disconnected via the movable slide unit.

[0037] If necessary, a single first connection or multiple first connections may be provided, which are connectable or disconnectable. Furthermore, if necessary, only a single second connection or multiple second connections may be provided, which are connectable or disconnectable.

[0038] Furthermore, a single third port or a plurality of third ports may be provided, which has / have a permanent fluid connection to the main chamber.

[0039] By having the outer surface of the slide unit and the inner surface of the sleeve element interact at least section by section, in particular forming a fluid-tight sliding connection, a fluid connection between connections of the housing body via the main chamber can be provided by releasing or separating a connection opening of the sleeve element through such interaction.

[0040] Depending on the design of the housing component of the valve assembly with first, second and / or third ports, a multitude of fluid connections between the first, second and / or third ports of the housing component can be provided by means of the pressure-balanced slide unit in operative connection with the sleeve elements via / along the main chamber in order to ensure appropriate interconnection or use of the valve assembly.

[0041] According to a further preferred embodiment of the present invention, the slide unit has at least one sealing section along the outside for interaction with the inside of the sleeve element, in particular for interaction with a counter section of the inside of the sleeve element, so that a fluid connection between the first port, the second port and / or the third port can be disconnected as required.

[0042] In particular, sections can be provided along the outside of the slide unit and along the inside of the sleeve element, designed and configured for interaction with each other, especially so that a sealing effect can be provided as needed. Within the valve assembly, fluid connections between various ports of the housing components can be established or disconnected depending on the position of the pressure-balanced slide unit.

[0043] According to a further embodiment, the sealing section of the slide unit, designed to interact with the opposite section of the sleeve element, is provided in such a way, in particular with an effective surface designed in such a way in combination with the opposite section of the sleeve element, that the at least one sealing section forms a stop for the movable slide unit with the at least one opposite section.

[0044] Accordingly, a sealing section of the slide unit can have a specific geometric design, so that a fluid-sealing end stop can be provided for the pressure-balanced slide unit.

[0045] In a preferred embodiment, the valve assembly has a drive unit, preferably an electromagnet, for moving the slide unit, preferably for translational movement in a longitudinal direction of the valve assembly.

[0046] The drive unit ensures targeted and efficient positioning and movement of the pressure-balanced slide unit within the main chamber.

[0047] According to a further embodiment, the valve assembly has at least one preloading element, in particular a spring element, for preloading the slide unit in a direction of movement of the slide unit.

[0048] According to another preferred embodiment, a preloading element is arranged in the slide unit.

[0049] - on the drive unit or

[0050] - within the main chamber in the region of a longitudinal end of the valve assembly, in direct or indirect contact with the slide assembly. The pre-tensioning element can be used, in particular, to pre-condition the pressure-balanced slide assembly.

[0051] This allows the slide unit to be moved to a specific position in the unloaded, uncontrolled, or unpowered state of the valve assembly, in order to ensure a targeted initial state of the valve assembly.

[0052] According to a subordinate aspect of the invention, an electro-hydraulic steering system for a vehicle, in particular a commercial vehicle, is provided with a valve device according to the invention.

[0053] According to a preferred embodiment, the steering system further comprises:

[0054] - at least one steering gear, in particular a screw steering gear;

[0055] - at least one first line through which the steering gear can be supplied with hydraulic fluid and / or controlled;

[0056] - at least one second line through which the steering gear can be supplied with hydraulic fluid and / or controlled; and

[0057] - at least one valve device connected or connectable to the first line and / or the second line according to one of the preceding claims for pressure reduction in the first line and / or the second line, wherein the valve device is actuable as required, in particular electromagnetically actuated.

[0058] The design of the valve assembly with a pressure-balanced slide unit ensures a targeted, efficient and dynamic supply of changing or alternating fluid connections along first, second and / or third ports.

[0059] According to the present invention, for example, an advantageous pressure reduction within the electro-hydraulic steering system can be ensured by means of the valve device in order to guarantee a suitable and safe functioning of the steering system.

[0060] In a further subordinate aspect, a vehicle, in particular a commercial vehicle, is provided with an electro-hydraulic steering system according to the present invention and / or a valve device according to the invention.

[0061] All structural and functional features related to the valve device described above and the possible embodiments can also be provided, alone or in combination, in the steering system and / or the vehicle according to the invention, and the associated advantages can be achieved accordingly.

[0062] Further details and advantages of the invention will now be explained in more detail with reference to the exemplary embodiments shown in the schematic drawings.

[0063] They show:

[0064] Fig. 1 shows a sectional view of an embodiment of a valve device in various switching states;

[0065] Fig. 2 shows a sectional view of another embodiment of a

[0066] Valve assembly;

[0067] Fig. 3 shows a sectional view of another embodiment of a

[0068] Valve assembly;

[0069] Fig. 4 shows a representation of various configurations for a valve assembly, in particular according to one of the embodiments shown in Figs. 1 to 3; Fig. 5 shows a sectional view of another embodiment of a

[0070] Valve assembly;

[0071] Fig. 6 shows a sectional view of another embodiment of a

[0072] Valve assembly;

[0073] Fig. 7 shows a circuit arrangement of an embodiment of a steering system;

[0074] Fig. 8 shows a representation of a circuit arrangement of another

[0075] Exemplary embodiment of a steering system;

[0076] Fig. 9 shows a representation of a circuit arrangement of another

[0077] Exemplary embodiment of a steering system;

[0078] Fig. 10 shows a representation of a circuit arrangement of another

[0079] Exemplary embodiment of a steering system;

[0080] Fig. 11 shows a schematic representation of a circuit arrangement of a further embodiment of a steering system;

[0081] Fig. 12 shows a schematic representation of a circuit arrangement of another embodiment of a steering system;

[0082] Fig. 13 shows a schematic representation of a circuit arrangement of a further embodiment of a steering system;

[0083] Fig. 14 shows a schematic representation of a circuit arrangement of another

[0084] Exemplary embodiment of a steering system; and

[0085] Fig. 15 shows a sectional view of another embodiment of a valve device. Fig. 1 shows a sectional view of an embodiment of a valve device 100 in various switching states.

[0086] The valve assembly 100 is provided according to Fig. 1 with a housing body 110 in which a main chamber 120 is formed, with a slide unit 130, a sleeve element 140 and a drive unit 150.

[0087] In particular, the valve assembly according to Fig. 1 is designed as a normally open 3 / 3 valve.

[0088] The housing body 110 can be designed in one piece or in multiple parts. According to Fig. 1, a multi-part design is provided, wherein the housing body 110 can be provided with a separately designed upper part for closing the main chamber 120.

[0089] The housing body 110 can extend along a longitudinal axis X as shown in Fig. 1.

[0090] Furthermore, as can be seen in Fig. 1, the drive unit 150 is attached to a longitudinal end of the housing body 110. The slide unit 130 is movable within the main chamber 120 by means of the drive unit 150, in particular translationally displaceable in the direction of the longitudinal axis X.

[0091] The housing body 110 and the components arranged therein can be designed symmetrically, in particular rotationally symmetrically, with respect to the longitudinal axis X.

[0092] A piston rod 152 extends from the drive unit 150 into the main chamber 120 and into the slide unit 130. The slide unit 130 is coupled to the drive unit 150 via the piston rod 152.

[0093] According to Fig. 1, the housing body can further be provided with at least one first (hydraulic) connection 111, at least one second (hydraulic) connection 112, and at least one third (hydraulic) connection 113. The first and second connections 111 and 112 can, for example, serve as hydraulic connections for hydraulic lines, preferably for a bidirectional steering gear. The third connection 113 can, for example, serve as a connection for a supply line to a hydraulic tank.

[0094] As shown in Fig. 1, the first and third ports 111 and 113 are provided as pressure ports (designation according to Fig. 1: P1, P2), with the second port 112 being provided as a port for a hydraulic tank (designation according to Fig. 1: T).

[0095] The slide unit 130 and the sleeve element 140 are arranged within the housing body 110. The sleeve element 140 is fixedly arranged within the housing body 110. The slide unit 130 is movable within the main chamber 120, in particular translationally displaceable.

[0096] The slide unit 130 can be understood as being arranged in the main chamber 120. In this sense, the sleeve element can be understood as being arranged within the housing body 110, wherein the main chamber 120 is determined or defined by the sleeve element 140 in conjunction with the housing body 110.

[0097] The sleeve element 140 can be configured with at least one first connection opening 141 and at least one second connection opening 142. As shown in Fig. 1, preferably at least two first and second connection openings 141 and 142 are provided.

[0098] The first connection opening 141 is designed along the sleeve element 140 such that it is essentially aligned with or oriented towards the first connection 111 of the housing body 110. The second connection opening 142 is designed along the sleeve element 140 such that it is essentially aligned with or oriented towards the second connection 112 of the housing body 110. Furthermore, the sleeve element 140 is designed along one outer surface such that a flow path from the first and second connection opening 141; 142 to the first and second connections 111; 112, respectively, is ensured. Here, the sleeve element 140 has a flow path groove 148 along its outer surface for each of the first and second connection openings 141; 142.

[0099] In particular, the flow path grooves 148 can each be circumferential flow path grooves 148, so that a fluid connection is provided between several first or second connection openings 141 ; 142 arranged distributed along a circumference of the sleeve element 140 and to the first or second connection 111 ; 112 of the housing body 110.

[0100] Adjacently arranged flow path grooves 148 can be hydraulically separated from each other by means of sealing elements on the sleeve element 140 and / or on the housing body 110.

[0101] Furthermore, the sleeve element 140 has an inner surface 144. The inner surface 144 is designed to interact or interact, particularly sectionally, with the slide unit 130, and in particular with an outer surface 136 of the slide unit 130.

[0102] The slide unit 130 can be designed as a single piece or as a multi-piece unit. According to Fig. 1, the slide unit 130 has a separately formed cover element 132, in conjunction with a shell section or shell element.

[0103] The slide unit 130 can essentially be designed in a pot shape.

[0104] Within the main chamber 120, the slide unit is provided to be movable, in particular to be displaceable along the longitudinal axis X of the valve assembly 100.

[0105] The valve unit 130 divides the main chamber 120 into a first section 122 and a second section 124. The volumes of the two sections 122 and 124 can complement each other depending on the position of the valve unit 130 within the main chamber 120, forming the main chamber 120 as a whole.

[0106] In particular, the main chamber 120 can be understood as being limited or formed by an inner side of the housing body 110 and an inner side 144 of the sleeve element 140.

[0107] The slide unit 130 has at least one through-opening 134, so that a fluid connection between the first section 122 and the second section 124 of the main chamber 120 can be provided.

[0108] According to Fig. 1, two or more passage openings 134, symmetrically designed with respect to the longitudinal axis X, can be provided.

[0109] Preferably, the at least one through-opening 134 can be configured as a fluid connection, a fluid channel, or the like, in the sense of a short circuit. Alternatively, filter elements, throttling elements, or the like can be provided in the at least one through-opening 134.

[0110] Pressure equalization between the first and second sections 122; 124 of the main chamber 120 is possible via the passage openings of the valve unit 134.

[0111] The adjustment or movement of the slide element 130 within the main chamber 120 shall occur, at least substantially, independently of or without the influence of a fluid pressure difference between the first and second sections 122; 124. The slide unit 130 is designed as a pressure-balanced slide unit, at least substantially.

[0112] Furthermore, the sliding unit 130 has an outer surface 136.

[0113] The outer surface 136 of the slide unit 130 is provided, at least in sections, for interaction with the inner surface 144 of the sleeve element, in particular for the joint formation of a fluid-tight sliding connection along which the slide unit 130 is movable within the main chamber 120.

[0114] According to Fig. 1, the outer surface 136 can have a U-shaped basic form.

[0115] In particular, the gate unit 130 can be designed with a flow path groove 137 along the outside 136.

[0116] Preferably, the at least one flow path groove 137 along the outer side 136 of the slide element 130 is designed such that a fluid connection between the at least one first and second connection opening 142 of the sleeve element 140 can be provided as required by means of the flow path groove 137 of the slide unit 130, in particular depending on the positioning position of the slide unit 130 within the main chamber 120.

[0117] Furthermore, a fluid connection between the at least one first and second connection opening 142 of the sleeve element 140 can be separated as required by means of the fluid-tightly interacting outer surface 136 and inner surface 144, in particular if the slide unit 136 assumes a different or different position within the main chamber 120.

[0118] According to Fig. 1, the housing body 110 has a third connection 113. In particular, the third connection 113 can be formed at a longitudinal end, preferably opposite the drive unit 150.

[0119] The third connection 113 can be provided in such a way that a continuous fluid connection to the main chamber 120, in particular to the second section 124, is present, regardless of the position of the slide unit 130.

[0120] According to the embodiment shown in Fig. 1, various fluid connections within the valve assembly 100 can be provided and disconnected by means of the movable, pressure-balanced slide unit 130, as illustrated in Fig. 1 by the different switching states. On the one hand, a fluid connection between the first port 111 and the third port 113 can be provided via the main chamber 120 or the second section 124, the first connection opening 141 and the associated flow path groove 148 of the sleeve element (see Fig. 1, left-hand illustration). For this purpose, the slide unit 130 can assume a position by which the second connection opening 142 of the sleeve element 140 can be covered fluid-tight by the outer surface 136 of the slide unit 130, in conjunction with the inner surface 144.

[0121] In another position of the slide unit 130, a fluid connection between the first port 111 and the second port 112 can be provided via the first and second port openings 141 and 142 and the respective associated flow path grooves 148 of the sleeve element 140 (see Fig. 1, center view). The specific position of the slide unit 130 can align the flow path groove 137 with respect to the first and second port openings 141 and 142 such that a fluid-tight fluid connection is provided within the main chamber 120, in particular fluid-tightly separated from the first and second sections 122 and 124. The flow path groove 137 of the slide unit 130 can be understood as a type of short circuit. In particular, the slide unit 130 with the flow path groove 137 provides a direct and isolated fluid connection between the first and second port openings 141 and 142. 142 or the first and second connections 111; 112 are ready.

[0122] Furthermore, a fluid connection between the second and third ports 112 and 113 can be provided by means of an additional positioning position of the slide unit 130 (see Fig. 1, right-hand illustration). For this purpose, the slide unit 130 can be positioned such that the first connection opening 141 is fluid-tightly separated by the outer surface 136 of the slide unit 130, in particular from the main chamber 120. Preferably, the flow path groove 137 of the slide unit 130 can completely overlap and encompass the first connection opening 141. The fluid connection can then extend from the first port 112, via the flow path groove 148 and the second connection opening 142 of the sleeve element 140, into the main chamber 120 and thus provide access to the third port 113.In particular, the fluid connection can extend within the main chamber 120 from the first section 122 via the at least one passage opening 134 of the slide unit 130 into the second section 122, to which the third connection 113 according to Fig. 1 is directly connected.

[0123] For example, by means of a valve device 100, as shown in a first embodiment according to Fig. 1, it is conceivable to implement various functionalities in an electro-hydraulic steering gear.

[0124] Based on a fluid connection or hydraulic connection between one of the pressure ports P1 or P2 (in Fig. 1: first port 111 or third port 113), and a hydraulic tank T (in Fig. 1: second port 112), depending on the pressure conditions at the first or second (pressure) port 111 or 112,

[0125] - a low-pressure function to improve the dynamics of the (electrohydraulic (steering) system;

[0126] - a leakage function to facilitate pump operation, to minimize (pressure / volume flow) fluctuations at low speeds and / or to increase the efficiency of the pump function, in particular by skipping or omitting a critical operating range of the pump (due to mixing and friction behavior) and ensuring an optimal operating range;

[0127] - a heating function for warming the hydraulic fluid, the hydraulic pump 1114 and / or the steering gear 1102, during operation (i.e. by means of a connection between one of the pressure ports P1 or P2 with the hydraulic tank T) or when the hydraulic pump is idling (i.e. hydraulic short circuit within the valve assembly 100 between the pressure ports P1 and P2), wherein heating in a unidirectional (delivery) direction only or in a bidirectional (delivery seal of the hydraulic pump 1114) direction is conceivable;

[0128] - a damping function based on a (targeted) leakage between the pressure side and the tank;

[0129] - a function for refilling the tank with hydraulic fluid and / or

[0130] - a backup function for an electro-hydraulic steering system is implemented (see Fig. 1, center and right illustrations).

[0131] Provided that the pressure connections P1 and P2 (in Fig. 1: first and third connection 111; 113) are hydraulically connected to each other and the (hydraulic) tank (in Fig. 1: second connection 112) is hydraulically separated by means of the slide element 130 or the flow path groove 137, a parking heater function can be implemented during idling (see Fig. 1, left illustration).

[0132] Based on the specific design of the sleeve element 140, a normally open 3 / 3-way valve can be implemented by means of various positioning positions of the pressure-balanced slide unit 130 within the main chamber 120.

[0133] The normally open position of the valve assembly 100 is to be understood as a fluid connection of the pressure ports according to the first with the third port 111 ; 113 (in Fig. 1 : P1 and P2) according to Fig. 1.

[0134] The valve unit 100 represents a cost-effective solution that also takes up little installation space and allows for efficient and dynamic control.

[0135] Fig. 2 shows a sectional view of another embodiment of a valve device 100. The differences compared to the embodiments described above will be discussed in detail below.

[0136] In Fig. 2, the valve assembly 100 is shown as a normally closed 3 / 3-way valve. According to Fig. 2, the spool unit 130 is designed along its outer surface such that, in the de-energized state, the first port 111 is hydraulically isolated (see Fig. 2: left-hand illustration).

[0137] In particular, the flow path groove 137 can be designed to be smaller than in the embodiment shown in Fig. 1, such that a larger interaction surface is provided along the outer surface 136 of the slide unit 136. Preferably, the (interaction) surface of the outer surface 136 of the slide unit 130, which is provided for interaction with the inner surface 146 of the sleeve element 140, can be designed to be so large that the first and / or the second connection opening 141; 142 of the sleeve element can be completely covered or separated.

[0138] According to Fig. 2, the at least one first connection opening 141 is covered and hydraulically separated by means of the outer surface 136 of the slide unit 130.

[0139] Furthermore, according to Fig. 2, the second connection opening is hydraulically separated by the valve unit 130, in particular by means of an overlap of the flow path groove 137 of the valve unit 130.

[0140] As shown in Fig. 2, the first connection 111, the second connection 112 and the third connection 113 can be hydraulically separated from each other.

[0141] In particular, the outer surface 136 of the slide element 130 is designed such that the first connection 111, the second connection 112 and the third connection 113 can be separated (hydraulically) from each other.

[0142] Furthermore, according to Fig. 2, in contrast to the embodiment shown in Fig. 1, the arrangement of a prestressing element 160 is provided.

[0143] In particular, it is provided that the pretensioning element 160 pretensions the slide unit 130 in one direction of movement.

[0144] The preloading element 160 is arranged inside the main chamber 120 according to Fig. 2, for preloading the slide unit 130 in the direction of the longitudinal axis X.

[0145] The preload element 160 can be located at one end of the main chamber 120 opposite the drive unit and in direct contact with the slide unit 130. Alternatively, the preload element 160 can be arranged in indirect contact with the slide unit 130. According to Fig. 2, the preload element 160 is designed as a spring, in particular as a compression spring.

[0146] For example, the embodiment shown in Fig. 2 allows for the implementation of various functionalities in an electro-hydraulic steering gear, starting from the functions described in the embodiment shown in Fig. 1:

[0147] - Low-pressure function to improve the dynamics of the (electrohydraulic (steering) system;

[0148] - a leakage function to facilitate pump operation, to minimize (pressure / volume flow) fluctuations at low speeds and / or to increase the efficiency of the pump function, in particular by skipping or omitting a critical operating range of the pump (due to mixing and friction behavior) and ensuring an optimal operating range;

[0149] - a heating function for warming the hydraulic fluid, the hydraulic pump 1114 and / or the steering gear 1102 during operation (i.e. by means of a connection between one of the pressure ports P1 or P2 with the hydraulic tank T), wherein heating in a unidirectional (delivery) direction only or in a bidirectional (delivery seal of the hydraulic pump 1114) direction is conceivable;

[0150] - a damping function based on a (targeted) leakage between the pressure side P1 ; P2 and the tank T (in Fig. 2: first or third port 111 ; 113 in conjunction with the second port 112);

[0151] - a function for refilling the tank with hydraulic fluid.

[0152] Based on the design of the valve assembly with the preloading element 160, a normally closed 3 / 3-way valve can be implemented according to Fig. 2.

[0153] Fig. 3 shows a sectional view of another embodiment of a valve assembly. The differences compared to the embodiments described above will be discussed in detail below. According to Fig. 3, in contrast to the embodiment shown in Fig. 2, the preload element 160 can be arranged in direct or indirect contact with the drive unit 150.

[0154] In particular, the preloading element 160 can be arranged in a recess of the housing body 110 on the drive unit 150, preferably arranged concentrically to the piston rod 152.

[0155] Fig. 4 shows a representation of various configurations for a valve assembly 100, in particular according to one of the embodiments according to Figs. 1 to 3. In particular, Fig. 4 shows an outside of the sleeve element 140 in expanded form.

[0156] As shown in Fig. 4, it can be provided that three first and three second connection openings 141 ; 142 are arranged distributed along the sleeve element 140.

[0157] In particular, the connection openings 141 ; 142 are arranged distributed along the respective associated river channel grooves 148.

[0158] Furthermore, the first and second connection openings 141 ; 142 according to Fig. 4 can have different geometries or be designed with different geometries.

[0159] It is conceivable that the first and second connection openings 141, 142 have a circular shape, a square or rectangular shape, a triangular shape, a rhombus shape, an elliptical shape or the like.

[0160] The geometry of the connection openings 141; 142 along the sleeve element 140 allows for the influence of the control behavior in conjunction with the slide unit 130, particularly the outer surface 136 of the slide unit 130, and / or the flow behavior during the presence of a (partial) fluid connection. Fig. 5 shows a sectional view of another embodiment of a valve assembly 100. The differences compared to the embodiments described above will be discussed in detail below.

[0161] The embodiment shown in Fig. 5 can act or be used as a switching or proportional valve, as shown in Fig. 5 as a proportional valve.

[0162] According to Fig. 5, the first port 111 can be provided for connection to a (hydraulic) tank, the second port 112 as a pressure port for connection to a second pressure line (in Fig. 5: P2), and the third port 113 as a pressure port for connection to a second pressure line (in Fig. 5: P1). Alternatively, different configurations or assignments of ports 111, 112, and 113 are conceivable, as shown, among other things, in Fig. 1.

[0163] According to Fig. 5, it is further provided that the slide unit 130 has at least one additionally formed sealing section 138 along the alternating or cooperating outer surface 136.

[0164] The sleeve element 140 can be configured to correspond with at least one counter-section 146.

[0165] As shown in Fig. 5, the slide unit 130 has a projection along its outer surface 136, which is formed with two inclined or chamfered sealing sections or sealing surfaces 138. The sealing sections or sealing surfaces are designed for fluid-tight engagement or contact with corresponding counter sections 146 of the sleeve element 140.

[0166] In particular, the sleeve element 140 according to Fig. 5 can be understood as being designed in multiple parts and / or supplemented by the design of the housing body 110, which preferably forms or delimits the main chamber 120. The inner surface 144 is expediently designed to form the corresponding counter-sections 146.

[0167] As shown in Fig. 5, the inner surface 144 can have a recess or indentation in the area of ​​the first outlet opening 141, which allows at least partial engagement of the projection of the outer surface 136 with the sealing sections 137. The projection with the sealing sections 137 can move along the recess on the inner surface 144 according to the mobility of the slide unit 130, with the opposing sections 146 forming a stop in each case.

[0168] When a sealing section 138 is brought into suitable contact with a counter section 146 according to a corresponding positioning position of the slide unit 130, a fluid-tight connection is preferably formed along this contact.

[0169] Thus, as shown in Fig. 5, a fluid connection can be provided using the opposing sections 146 as (end) stops for a positioning position of the slide unit 130.

[0170] - between the first port 111 (according to Fig. 5: hydraulic tank T) and the third port 113 (according to Fig. 5: pressure port P1) or

[0171] - between the second port 112 (according to Fig. 5: pressure port P2) and the first port 111 (according to Fig. 5: hydraulic tank T).

[0172] A hydraulic fluid connection between the second port 112 (according to Fig. 5: pressure port P2) and the third port 113 (according to Fig. 5: pressure port P1) is not provided according to Fig. 5.

[0173] The implementable functionalities in the case of the embodiment according to Fig. 5 are comparable to the functionalities described for the embodiment according to Fig. 2.

[0174] In particular, the valve assembly 100 according to Fig. 5 can be implemented as a normally open 3 / 2-way valve. Fig. 6 shows a sectional view of another embodiment of a valve assembly 100. The differences compared to the embodiments described above will be discussed in detail below.

[0175] In contrast to Fig. 5, Fig. 6 shows a further variant of a valve device 100 with at least one sealing section 137 and at least one counter section 146.

[0176] The embodiment shown in Fig. 6 can preferably act or be used as a proportional valve.

[0177] According to Fig. 6, the housing body has only the first connection 111 and the third connection 113. The first connection 111 and the second connection 112 can be used as pressure connections (P1 and P2, as shown in Fig. 6). Alternatively, for example, one of the first and third connections 111 and 113 could be connected to a (hydraulic) tank.

[0178] Corresponding to the design of the housing body 110 with only one first and one third connection 111 ; 113, the sleeve element 140 is designed with at least one first outlet opening 141 and an associated flow path groove 148.

[0179] Thus, the sleeve element 140 according to Fig. 6 in particular does not have a second connection opening 142.

[0180] Furthermore, as shown in Fig. 6, the outer surface 136 of the valve unit 130 does not have a flow path groove 137.

[0181] The outer surface 136 of the slide unit 130 is designed, as shown in Fig. 6, to interact with the inner surface 144 of the sleeve element 140 such that a counter section 146 forms a single stop for the sealing section 138 of the outer surface 136. According to Fig. 6, the sealing section 138 can be formed at a longitudinal end of the slide unit 130 as a single-stage or multi-stage chamfer on the outer surface 136 such that the slide unit 130 can come into contact with the counter section 146 in a corresponding position, forming a fluid-tight (contact) connection.

[0182] In particular, the sealing section 138 can be formed along the outside 136 at one end of the slide unit 130 facing the drive unit or the third connection 113.

[0183] Thus, as shown in Fig. 6, it is provided that with fluid-tight contact between the sealing section 138 and the opposing section 146, as well as in further fluid-tight interaction of the remaining outer surface 136 with the inner surface 144, a hydraulic separation of the first connection 111 from the third connection 113 can take place.

[0184] If the slide unit 130 is moved to a further positioning position, the fluid-sealing contact between the counter section 146 and the sealing section 138 is released, and a fluid connection can be established from the first port 111 via the flow path groove 148, which provides at least one first connection opening 141 into the first section 122 of the main chamber 120. From the first section 122 of the main chamber 120, the fluid connection can be continued via the at least one through-opening 134 of the pressure-balanced slide unit 130 into the second section 124 and up to the third port 113 of the housing body 110.

[0185] Furthermore, it can be seen from Fig. 6, especially compared to Fig. 5, that the sealing section 138 can be designed in multiple stages.

[0186] The sealing section 138 is illustrated in Fig. 6 as a two-stage sealing section 138, wherein the sealing section 138 has two differently shaped areas, in particular two areas with different chamfers. Preferably, the two or more areas of the sealing section 138 can be separated from each other in fluid-tight contact with the sleeve element by the opposing section 146.

[0187] By designing the sealing section 138 as a multi-stage sealing section 138, a changing behavior of the slide unit 130 during pressure build-up before, during and after the occurrence or dissolution of a (fluid-)sealing contact between the slide unit 130 and the sleeve element 140 can be provided.

[0188] Furthermore, according to Fig. 6, the preload element 160, preferably in the form of a (compression) spring, can be provided within the main chamber 120, in particular the second section 124, and in direct contact with the slide unit 130.

[0189] The preloading element 160 can be used to preload the slide unit 130 in the direction of or against the opposite section 146 as a stop.

[0190] For example, the embodiment shown in Fig. 6 illustrates the implementation of various functionalities in an electro-hydraulic steering gear, starting from the functions described in Fig. 1:

[0191] - a leakage function to facilitate pump operation, to minimize (pressure / volume flow) fluctuations at low speeds and / or to increase the efficiency of the pump function, in particular by skipping or omitting a critical operating range of the pump (due to mixing and friction behavior) and ensuring an optimal operating range; a heating function to warm the hydraulic fluid, the hydraulic pump 1114 and / or the steering gear 1102, during the idling of the hydraulic pump (i.e., hydraulic short circuit within the valve assembly 100 between the pressure ports P1 and P2), whereby heating in a unidirectional (delivery) direction only or in a bidirectional (delivery) direction of the hydraulic pump 1114 is conceivable; - a damping function based on a (targeted) leakage between the pressure side P1; P2 and the tank T (in Fig.2: first or third connection 111; 113 in conjunction with the second connection 112);.

[0192] - a backup function for an electro-hydraulic steering system.

[0193] Based on the design of the valve assembly according to Fig. 6, a normally closed 2 / 2-way valve or 2 / 2-proportional valve can be implemented.

[0194] In general, all embodiments of a valve device 100 shown within the scope of this invention can be designed as a directional control valve, a spool valve, or an on / off valve, or as a proportional valve with appropriately designed, in particular single-stage or multi-stage beveled, sealing sections 138 along the outside 136 of the spool unit 130.

[0195] Furthermore, in accordance with the present invention, it is conceivable that the design as a proportional valve can be provided by a targeted structuring or surface (size) modification of the outside 136 of the slide unit 130, for example in the form of grooves or the like.

[0196] Fig. 7 shows a representation of a circuit arrangement of an embodiment of a steering system 1000. In particular, the electro-hydraulic steering system 1000 can have a valve device 100 according to one of the embodiments described above in Figs. 1 to 6.

[0197] The electro-hydraulic steering system 1000 for a commercial vehicle has a steering gear 1102 in the form of a spindle steering gear.

[0198] The screw steering gear 1102 can be designed as a ball screw steering gear, although other types of gears are also conceivable.

[0199] The electro-hydraulic steering system 1000 further comprises a first line 1104 through which the steering gear 1102 can be supplied with hydraulic fluid and controlled. Accordingly, the electro-hydraulic steering system 1000 comprises a second line 1106 through which the steering gear 1102 can also be supplied with hydraulic fluid and controlled.

[0200] Furthermore, the steering system 1000 has a valve assembly 100, preferably a valve assembly 100 according to one of the embodiments shown in Figs. 1 to 6.

[0201] The valve assembly 100 can, for example, be designed as a 3 / 3-way valve assembly, an on / off valve assembly, or a low-pressure valve assembly.

[0202] The valve assembly 100 is connected on the input side to the first line 1104 and also on the input side to the second line 1106.

[0203] According to Fig. 7, the valve assembly 100 is also connected or connectable on the output side via a return line 1112 of the steering system 1000 to a hydraulic tank 1110.

[0204] Therefore, a hydraulic fluid can be transferred or forwarded to the hydraulic tank 1110 via the valve device 100.

[0205] Furthermore, the valve device 100 can, for example, be used for pressure reduction in the first line 1104 and / or the second line 1106.

[0206] The valve assembly 100 can be actuated or controlled on demand, preferably electromagnetically, by means of a control unit that is assigned to or associated with the steering system 1000 and is not shown in the figures.

[0207] Furthermore, the pump unit 1114 is connected to the first and second lines 1104, 1106.

[0208] The pump unit 1114 can be designed as a double-acting hydraulic pump, so that, depending on the direction of rotation, either the first line 1104 or the second line 1106 can be pressurized. Alternatively, it is also conceivable that only a single-acting hydraulic pump is provided and is connected to the first and second lines 1104; 1106 via a corresponding switching valve (not shown in the figures), which, depending on the switching logic, connects the hydraulic pump to either the first or the second line 1104; 1106.

[0209] Alternatively, it may also be conceivable that two pump units 1114 could be provided, with one pump unit 1114 being assigned to or connected with the first or the second line 1104, 1106.

[0210] The pump unit 1114 in Fig. 7 can be connected to the steering gear 1102 via the first line 1104 and, alternatively, via the second line 1106, so that the actual connection depends on a direction control of the pump unit 1114.

[0211] Such control can be effected by a control unit that is assigned to or associated with the steering system 1000 and is not shown in the figures.

[0212] As can be seen in Fig. 7, the hydraulic tank 1110 is symbolically shown outside a module 1126 of the pump unit 1114. Alternatively, the hydraulic tank 1110 or an additional hydraulic tank can also be provided inside the module 1126 of the pump unit 1114 (see the following embodiments according to Figs. 11 to 13).

[0213] According to Fig. 7, the first line 1104 and the second line 1106 are connected to the hydraulic tank 1110 via the check valves 1118; 1120 (not explicitly illustrated in Fig. 7).

[0214] The two check valves 1118 and 1120 can be arranged such that hydraulic fluid can be supplied from the hydraulic tank 1110 to the pump 1114 via the check valves 1118 and 1120, while preventing backflow towards the hydraulic tank 1110. The first check valve 1118 and the second check valve 1120 can also serve and / or function as suction valves.

[0215] Advantageously, a pressure build-up, in particular a pressure build-up controllable or controlled via a control unit assignable or associated to the steering system 1000, for example the already named, can thus take place under the influence, preferably support, of the suction valves.

[0216] In other words, the first and second check valves 1118; 1120 can assist the pump 1114 in building up pressure, especially along the first and second lines respectively up to the steering gear 1102.

[0217] As can be seen in Fig. 7, the pump unit 1114 or the construction module 1126 can also be assigned a temperature sensor 1122 and a pressure sensor 1124, which are provided, for example, along the at least one suction line 1116.

[0218] It is understood that the temperature sensor 1122 and the pressure sensor 1124 can be connected or linked to the control unit of the pump unit 1114 and / or a control unit that can be assigned or associated with the steering system 1000, for example the one already mentioned above, for controlling an operation and / or partial operation of the steering system 1000 via signal technology.

[0219] Furthermore, as shown in Fig. 7, an additional backup valve 1160 can be provided on the steering gear 1102. Alternatively, such a backup valve 1160 can, for example, be integrated into the valve assembly 100.

[0220] As shown in Fig. 7, the backup valve 1160 can, on the one hand, be connected, at least indirectly, to the first line 1104 via the pressure chamber of the steering gear 1102 assigned to the first line 1104. On the other hand, the backup valve 1160 can be connected indirectly to the second line 1106 via the pressure chamber of the steering gear 1102 assigned to the second line 1106.

[0221] The respective pressure chambers of the steering gear 102 can be connected and preferably short-circuited by means of the backup valve 1160, especially in an emergency situation or in the event of a fault.

[0222] This allows the safety and / or reliability of the steering system 1000 to be further improved, as the pressure chambers of the steering gear 1102 can be connected in an emergency situation, thereby ensuring a corresponding pressure reduction or pressure equalization and thus a steering function in terms of the mobility of the (hydraulic) piston in the steering gear at all times.

[0223] In a sense, the backup valve 1160 can thus form and / or enable a fault circuit that is not specifically indicated in the figures and / or function as such.

[0224] In an emergency, the backup valve 1160 can switch from its closed position to a through position in order to provide a fluid short circuit between the two pressure chambers of the steering gear 1102.

[0225] Furthermore, the backup device or the backup valve device, in particular the backup valve 1160, can be controlled or controlled via a control unit that can be assigned to or associated with the steering system 1000.

[0226] The function of the steering system 1000 according to the embodiment shown in Fig. 6 can be described as follows:

[0227] As soon as the pump 1114 is driven by the drive unit or the electric motor (e.g., counterclockwise), it can pressurize the section of the first line 1104, which extends to the steering gear 1102 and to a first connection 1128 of the valve assembly 100, with hydraulic fluid pressure. For short-term and / or long-term temperature control of the hydraulic fluid during commissioning or continuous operation of the electro-hydraulic steering system 1000, the hydraulic fluid can be circulated by means of the pump unit 1114 and via the valve assembly 100 along the return line 1112.

[0228] In particular, the pump 1114 can pump the hydraulic fluid via the first or second pump fluid connection along the first or second line 1104; 1106 to the valve assembly 100 with the inlet connections 1128; 1130.

[0229] Using the valve device 100, the hydraulic fluid can be returned directly to the hydraulic tank 1110 via the return line 1112.

[0230] Furthermore, the pressure build-up for the application of steering assistance can be carried out using the present steering system 1000 as described below:

[0231] During the pressure build-up for the application of steering assistance, the hydraulic pump 1114 can be supported by the second check valve 1120, which acts as a suction valve, especially if the pump 1114 generates a sufficient negative pressure along the second line 1106, which leads to the opening of the second check valve 1120.

[0232] Consequently, the pump 1114 and the steering gear 1102 are connected to each other via the first line 1104 and the connection of the steering gear 1102 connected to the first line 1104 is printed.

[0233] As a result, the pressure in the assigned first pressure chamber of the steering gear 1102 increases, and the piston is forced into a displacement movement because the pressure in the opposite, second pressure chamber is lower, thus achieving steering assistance. In this sense, the second pressure chamber can be understood as a low-pressure chamber. The pressure in the opposite second pressure chamber is lower because the steering gear 1102 is connected to the return line 1112 via the section of the second line 1106 and the valve assembly 100.

[0234] In this case, the hydraulic fluid is displaced from the opposite, second pressure chamber and via the valve assembly 100 into the return line 1112 and then fed back to the hydraulic tank 1110 via the return line 1112.

[0235] A rapid return of the hydraulic fluid can be initiated, for example, if the operating pressure in the first line 1104 is higher compared to the operating pressure in the second line 1106 and the second line 1106 is connected to the return line 1112 by means of the at least partially controllable valve device 100.

[0236] Thus, the second line 1106 can be connected to the return line 1112 depending on the pressure difference between the first line 1104 and the second line 1106 and the actuable valve device 100.

[0237] This enables a rapid pressure relief phase in the pressure chamber of the steering gear 1102 connected to the second line 1106, and thus the response behavior of the steering system 1000 can be improved, preferably enabling a faster system response and a better steering feel.

[0238] It should be taken into account that the pump 1114 can preferably only be driven in one direction of rotation and therefore only the first or the second line 1104, 1106 can be printed on at any given time.

[0239] In the case described above, the first line 1104 is therefore pressurized by the hydraulic pump 1114, whereas the second line 1106 is not pressurized, at least in the section between pump 1114 and steering gear 1102 and / or valve assembly 100. If the direction of rotation of pump 120 is reversed, the previously described relationship or case occurs in exactly the opposite way, as described below:

[0240] As soon as the pump 1114 is driven by the drive unit or the electric motor (now clockwise), it prints the section of the second line 1106, which extends to the steering gear 1102 and to a second connection 1130 of the valve assembly 100.

[0241] During pressure build-up, the pump 1114 is supported by the first check valve 1118, which acts as a suction valve.

[0242] Consequently, the pump 1114 and the steering gear 1102 are now connected to each other via the second line 1106 and the connection of the steering gear 1102 connected to the second line 1106 is printed.

[0243] As a result, the pressure in the associated second pressure chamber of the steering gear 1102 increases, and the piston is forced into a displacement movement because the pressure in the opposite first pressure chamber is now lower, thus achieving steering assistance. In this case, the first pressure chamber of the steering gear 1102 can be considered a low-pressure chamber.

[0244] The pressure in the opposite first pressure chamber is therefore lower because the connection of the steering gear 1102 is connected to the return line 1112 via the section of the first line and via the valve assembly 100.

[0245] In this case, the hydraulic fluid is displaced from the opposite, first pressure chamber and directed via the valve assembly 100 into the return line 1112 and then fed back to the hydraulic tank 1110 via the return line 1112.

[0246] In this case, a rapid return of the hydraulic fluid can be initiated if the operating pressure in the second line 1106 is higher compared to the operating pressure in the first line 1104 and the first line 1104 is connected to the return line 1112 by means of the at least partially controllable valve device 100.

[0247] Thus, the first line 1104 can be connected to the return line 1112 depending on the pressure difference between the first line 1104 and the second line 1106 by means of the actuable valve device 100, preferably by means of the actively controllable valve device 100.

[0248] This enables a rapid pressure relief phase in the pressure chamber of the steering gear 1102 connected to the first line 1104, and thus the response behavior of the steering system 1000 can be improved, preferably enabling a faster system response and a better steering feel.

[0249] The pump 120 can preferably only be driven in one direction of rotation, and therefore only the first or the second line 1104; 1106 can be printed on at any given time.

[0250] In the second case described above, the second line 1106 is therefore printed by the (hydraulic) pump 120, whereas the first line 1104 is not printed, at least in the section between pump 1114 and steering gear 1102 and / or valve assembly 100.

[0251] In summary, it should also be noted that, depending on the direction of rotation of the pump, either the first or the second line 1104; 1106 is printed, so that the steering gear 1102 is preferably always printed by only one of the lines 1104; 1106 and thus the other line 1 104, 1106 (which is not printed) can be connected or is connected to the return line 1112 via the valve device 100.

[0252] Since the piston displacement direction of the piston in the steering gear 1102 also changes depending on the steering direction, the control / pressure of the steering gear 1102 via the first line 1104 or the second line 1106 also changes accordingly. By enabling a rapid pressure reduction using the valve assembly 100, the piston displacement direction can also be quickly changed, thus enabling a fast and dynamic change of steering direction.

[0253] Fig. 8 shows a representation of a circuit arrangement of a further embodiment of a steering system 1000. The differences compared to the embodiments described above will be discussed in detail below.

[0254] As shown in Fig. 8, as a possible alternative to the embodiment shown in Fig. 7, an additional or supplementary hydraulic tank 1210 can be provided within the assembly module 1126. In particular, the additional or supplementary hydraulic tank 1210 can be provided as an integral component of the assembly module 1126, for example, the hydraulic pump 1114, parallel to the hydraulic tank 1110 connected to or flanged to the assembly module 1126.

[0255] Furthermore, according to Fig. 8, and in contrast to Fig. 7, it can be provided that a return line check valve 1202 is provided along the return line 1112 between the (hydraulic) tank 1210 and the valve assembly 100.

[0256] In particular, the return line check valve 1202 can be arranged along the return line 1112 in such a way that an oil flow or oil leakage from the valve assembly 100 via return line 1112 into the hydraulic tank 1210 is provided or enabled and an opposite backflow, i.e. from the hydraulic tank 1210 via the return line 1112 to the valve assembly 100, can be prevented.

[0257] Fig. 9 shows a diagram of a circuit arrangement of a further embodiment of a steering system 1000. The differences compared to the embodiments described above will be discussed in detail below. The embodiment according to Fig. 9 differs from the embodiment according to Fig. 7, in particular, in the design of the hydraulic pump 1114 and the connection of the hydraulic tank 1110.

[0258] As shown in Fig. 9, the hydraulic pump 1114 is connected to the hydraulic tank 1110 only via the leakage line 1115.

[0259] The hydraulic tank 1110 has a fluid connection to the steering gear 1102 and the hydraulic pump 1114 via the return line 1112 with the valve assembly 100.

[0260] Therefore, the suction of hydraulic fluid from the (hydraulic) tank 1110 by the pump 1114 can only take place, or at least primarily, via the valve assembly 100 and the return line 1112.

[0261] Fig. 10 shows a representation of a circuit arrangement of a further embodiment of a steering system 1000. The differences compared to the embodiments described above will be discussed in detail below.

[0262] According to Fig. 10, in comparison to the embodiment according to Fig. 9, it is particularly provided that the steering system 1000 is designed without a separate backup valve 1160.

[0263] In particular, the backup valve 1160 can be integrated into the valve assembly 100. Alternatively, the steering system 1000 can be configured without a backup valve 1160.

[0264] Fig. 11 shows a schematic representation of a circuit arrangement of a further embodiment of a steering system 1000. The differences compared to the embodiments described above will be discussed in detail below. In accordance with Fig. 11, compared to the embodiment according to Fig. 7 and according to the embodiment according to Fig. 8, an additional or supplementary hydraulic tank 1210, in addition to and preferably in conjunction with the hydraulic tank 1110, can be provided within the assembly module 1126 as a possible alternative.

[0265] The valve assembly 100 is connected or connectable on the output side via the return line 1112 to the pump unit 1114, in particular to the module 1126 of the pump unit 1114, and to the associated hydraulic tank 1210, as shown in Fig. 11.

[0266] A filter unit 1208 can also be provided along the return line 1112, as shown in Fig. 11. In particular, the filter unit can be arranged between the additional hydraulic tank 1210 and the return line check valve 1202.

[0267] The filter unit can be designed as part of the module 1126, as shown in Fig. 11, or it can be attached to or flanged to the module 1126. Alternatively, the filter unit 1208 can be provided independently of the module 1126 along the return line 1112.

[0268] The valve device 100 can therefore transfer or forward a hydraulic fluid to the construction module 1126 of the hydraulic pump 1114 and into the hydraulic tank 12120, for example for efficient temperature control of the hydraulic fluid, for example during the initial commissioning of the electro-hydraulic steering system 1000.

[0269] As can be seen in Fig. 11, the hydraulic tank 1210, as part and / or supplement to the hydraulic tank 1110, is symbolically represented within the construction module 1126, in the sense of an integrated design.

[0270] The valve assembly 100 allows the hydraulic fluid to be returned directly to the hydraulic pump module 1114 via the return line 1112, in order to return to the hydraulic tanks 1110 and 1210. The valve assembly 100 preferably enables a short-circuit circulation of the hydraulic fluid through the hydraulic tanks 1110 and 1210 of the hydraulic pump 1114. This allows for the short-term adjustment of the hydraulic fluid's operating temperature and / or temperature control of the pump unit 1114 and other components of the steering system 1000.

[0271] In particular, efficiency can be increased and the operating temperature of the pump unit 1114 can be appropriately set by circulating only the smallest possible volume of hydraulic fluid via the short-circuited fluid connection along the valve assembly 100 and by increasing or adjusting the fluid temperature primarily within the construction module 1126 of the pump unit 1114.

[0272] Furthermore, according to Fig. 11, and in contrast to Fig. 7, it can be provided that a return line check valve 1202 and a filter device 1208 are provided along the return line 1112 between the pump unit 1114 and the valve assembly 100.

[0273] This arrangement has the advantage that the filter or filter assembly 1208 does not need to be located on the high-pressure side, but rather on the low-pressure side in the return line 1112. Consequently, the filter assembly 1208 can be mechanically less robust and structurally simpler, as it is not subjected to such high pressures. As a result, cost advantages can also be realized through this type of filter design.

[0274] Preferably, the return line check valve 1202 according to Fig. 9 is provided between the filter device 1208 and the valve device 100.

[0275] In particular, the return line check valve 1202 can be arranged along the return line 1112 such that an oil flow or oil leakage from the valve assembly 100 via the filter assembly 1208 and a hydraulic fluid connection into the hydraulic tank 1210 is provided or enabled, and a reverse backflow, i.e., from the hydraulic tank 1210 via the filter assembly 1208 to the valve assembly 100, can be prevented. Fig. 12 shows a schematic representation of a circuit arrangement of a further embodiment of a steering system 1000. The differences compared to the embodiments described above will be discussed in detail below.

[0276] In particular, according to Fig. 12, compared to the embodiment according to Fig. 11, it is provided that the filter unit 1208, in particular exclusively the filter unit 1208, is arranged along the return line.

[0277] Accordingly, the embodiment of a steering system 1000 according to Fig. 12 can be designed along the return line 1208 without a check valve 1202.

[0278] Furthermore, a third check valve 1152 can be arranged in the first line 1104 and a fourth check valve 1154 in the second line 1106, in particular between the valve assembly 100 or the steering gear 102 and the hydraulic pump 1114, so that backflow to the hydraulic pump 1114 or the baud module 1126 and the suction of hydraulic fluid from the steering gear 1102 by the pump 1114 can be prevented.

[0279] In the first and second lines 1104; 1106, two check valves 1118; 1120; 1152; 1154 can each be arranged, so that, depending on a rotation or delivery direction of the pump 120, a targeted suction of hydraulic fluid from the hydraulic tank 1110 is made possible.

[0280] The check valves 1118; 1120; 1152; 1154 prevent or stop the (hydraulic) pump 120 from drawing hydraulic fluid from the steering gear 1102 or the valve device 1108 along the first or second line 1104; 1106.

[0281] Fig. 13 shows a schematic representation of a circuit arrangement of a further embodiment of a steering system 1000. The differences compared to the embodiments described above will be discussed in detail below.

[0282] In particular, Fig. 13 represents an embodiment in the sense of a combination of the embodiments according to Figs. 11 and 12.

[0283] According to Fig. 13, the return line check valve 1202 is provided along the return line 1112 next to the filter unit 1208 to prevent hydraulic backflow from the hydraulic tank 1210 to the valve assembly 100.

[0284] In addition, the third and fourth check valves 1204 and 1206 are arranged along the first and second lines 1104 and 1106 to prevent hydraulic flow from the steering gear 1102 towards the hydraulic pump 1114.

[0285] Fig. 14 shows a schematic representation of a circuit arrangement of a further embodiment of a steering system 1000. The differences compared to the embodiments described above will be discussed in detail below.

[0286] According to Fig. 14, in contrast to the embodiment according to Fig. 7, the valve assembly 100 is designed without a return line 1112.

[0287] In particular, the valve assembly 100 does not have a return line 1112 to the hydraulic tank 1110.

[0288] The valve assembly 100 is exclusively connected to the first line 1104 and the second line 1106 via the first and second connections 1128 and 1130, respectively.

[0289] The valve assembly 100 according to Fig. 14 can, for example, be configured as a valve assembly 100 according to the embodiment shown in Fig. 6, in the sense of a 2 / 2-way valve. Fig. 15 shows a sectional view of another embodiment of a valve assembly 100. The differences compared to the embodiments described above will be discussed in detail below.

[0290] In particular, the valve assembly 100 according to Fig. 15 is provided as a proportional valve, wherein the slide unit 130 has at least one sealing section 138.

[0291] According to Fig. 15, compared to the embodiment shown in Fig. 6, the sealing section 138 at a longitudinal end of the slide unit 130 is designed as a single-stage sealing section 138, preferably as a continuously uniformly chamfered surface. In particular, the design according to Fig. 15 can be understood as providing single-stage proportional behavior, whereas the design according to Fig. 6 allows for multi-stage proportional behavior.

[0292] Furthermore, as shown in Fig. 15, the one-piece or multi-piece sleeve element 140 may not have a specifically designed counter-section 146 along its inner surface 144 for interaction with the sealing section 138. According to Fig. 15, to provide a (fluid-)sealing connection, interaction between the outer surface 136 of the slide unit 130 and the inner surface 144 of the sleeve element 140 may be provided.

[0293] In accordance with the embodiment shown in Fig. 15, the proportional behavior, in particular exclusively the proportional behavior, of the valve assembly 100 or the slide unit 130 is determined by means of the sealing section 138 of the slide unit 130.

[0294] The functionalities achievable in the embodiment according to Fig. 15, particularly the design of the pressure ports P1 and P2 as the first port 111 and third port 113, are comparable to those described for the embodiment according to Fig. 6. Based on the design of the valve assembly 100 according to Fig. 15, a normally closed 2 / 2-way valve or a 2 / 2-proportional valve can be implemented.

[0295] Furthermore, as another alternative in the sense of the embodiment according to Fig. 15, it is conceivable that a prestressing element 160 (not shown in Fig. 15) according to Fig.

[0296] 3 may be provided, preferably in a recess of the housing body 110 on the drive unit 150 and preferably arranged concentrically to the piston rod 152.

[0297] In summary, the present invention advantageously provides a valve device 100 with a pressure-balanced slide unit 130, which advantageously allows efficient control of hydraulic connections in, for example, an electro-hydraulic steering system 1000.

[0298] In particular, the valve device 100 enables the system dynamics or system response of the steering system 1000 to be reliably increased or accelerated during operation, especially during fast steering maneuvers.

[0299] In the case of an electro-hydraulic steering system 1000, optimized hydraulic steering assistance as well as improved steering feel for the driver of a vehicle can be ensured, among other things, by means of the valve device 100 according to the invention.

[0300] In particular, an actively, preferably electromagnetically, controllable design of the valve unit 100 can ensure a cost-effective, low-maintenance and simple implementation for reliable and rapid pressure control, e.g. in the sense of pressure reduction in a (low) pressure chamber of the steering gear.

[0301] Furthermore, the electromagnetically controlled and / or adjustable valve unit 100 allows for an advantageous design with regard to the installation space, cost, and weight of a steering system according to the present invention. REFERENCE MARK LIST

[0302] 100 valve assembly

[0303] 110 Housing bodies

[0304] 111 first connection

[0305] 112 second connection

[0306] 113 third connection

[0307] 120 Main Chamber

[0308] 122 first section

[0309] 124 second section

[0310] 130 slide unit

[0311] 132 Cover element

[0312] 134 Passage opening

[0313] 136 Outside

[0314] 137 River path groove (of the gate unit)

[0315] 138 Sealing section

[0316] 140 sleeve element

[0317] 141 first connection opening

[0318] 142 second connection opening

[0319] 144 Inside

[0320] 146 Opposite section

[0321] 148 Flow path groove (of the sleeve element)

[0322] 150 drive unit

[0323] 152 Piston rod

[0324] 160 Preload element

[0325] 1000 steering system

[0326] 1102 Steering gear

[0327] 1104 first line

[0328] 1106 second line

[0329] 1110 Hydraulic tank

[0330] 1112 Return line

[0331] 1114 Hydraulic pump

[0332] 1115 Leakage line 1116 Suction line

[0333] 1118 first check valve

[0334] 1120 second check valve

[0335] 1122 Temperature sensor 1124 Pressure sensor

[0336] 1126 Building module

[0337] 1128 first connection

[0338] 1130 second connection

[0339] 1160 Back-up valve 1202 Return line check valve

[0340] 1204 third check valve

[0341] 1206 fourth check valve

[0342] 1208 Filter unit

[0343] 1210 integrated hydraulic tank

[0344] Longitudinal axis

Claims

PATENT CLAIMS 1. Valve assembly (100), in particular for an electro-hydraulic steering system of a vehicle, comprising at least one housing body (110) having at least one main chamber (120) and at least one slide unit (130), wherein the slide unit (130) is arranged to be movable, preferably translationally displaceable, within the main chamber (120) of the housing body (110), wherein the slide unit (130) divides the main chamber (120) into a first section (122) and a second section (124), wherein the at least one slide unit (130) is provided as a pressure-balanced slide unit (130) and is designed such that at least substantially the same fluid pressure is present in the first section (122) and in the second section (124), in particular pressure equalization between the first section (122) and the second section (124) is provided via the at least one slide unit (130).

2. Valve assembly (100) according to claim 1 , characterized in that the slide unit (130), in particular a cover element (132) of the slide unit (130), has at least one through-opening (134) so ​​that a fluid connection between the first section (122) and the second section (124) of the main chamber (120) is provided or can be provided.

3. Valve assembly (100) according to one of the preceding claims, characterized in that the valve assembly (100) has at least one sleeve element (140) which is arranged inside the housing body (110), in particular is arranged immovably, wherein an inner side (144) of the sleeve element (140) and an outer side (136) of the movable slide unit (130) are provided to interact, in particular to form a sealing sliding connection section by section.

4. Valve assembly (100) according to one of the preceding claims, characterized in that the housing body (110) has at least one first connection (111), wherein the sleeve element (140) has at least one first connection opening (141), wherein the first connection opening (141) is formed along the sleeve element (140) in such a way as to correspond to the first connection (111) of the housing body (110), so that a fluid connection between the main chamber (120) and the first connection (111) of the housing body (110) can be provided as required, in particular depending on a positioning position of the movable slide unit (130) relative to the sleeve element (140).

5. Valve device (100) according to one of the preceding claims, characterized in that the housing body (110) has at least one second connection (113), wherein the sleeve element (140) has at least one second connection opening (142), wherein the second connection opening (142) is formed along the sleeve element (140) in such a way as to correspond to the second connection (112) of the housing body (110), so that a fluid connection between the main chamber (120) and the second connection (112) of the housing body (110) can be provided as required, in particular depending on a positioning position of the movable slide unit (130) relative to the sleeve element (140).

6. Valve device (100) according to one of the preceding claims, characterized in that the housing body (110) has at least one third connection (113), wherein the third connection is formed along the housing body (110) in such a way that a fluid connection to the main chamber (120) is provided regardless of the position of the movable slide unit (130).

7. Valve assembly (100) according to one of the preceding claims, in particular according to one of claims 4 to 6, characterized in that the slide unit (130) is designed and movable in such a way, in particular the outer side (136) of the slide unit (130) is provided to interact section by section with the inner side (144) of the sleeve element (140) such that, depending on an actuating position of the slide unit (130) - a fluid connection between the first port (111) and the second port (112) of the housing body (110) can be provided, - a fluid connection between the first port (111) and the third port (113) of the housing body (110) can be provided, - a fluid connection between the second port (112) and the third port (113) of the housing body (110) can be provided and / or - a fluid connection between the first, second and / or third port (111 ; 112; 113) of the housing body (110) is separable.

8. Valve assembly (100) according to one of the preceding claims, characterized in that the slide unit (130) has at least one sealing section (138) along the outside (136) for interacting with the inside of the sleeve element (140), in particular for interacting with a counter section (146) of the inside (144) of the sleeve element (140), so that a fluid connection between the first port (111), the second port (112) and / or the third port (113) can be disconnected as required.

9. Valve device (100) according to claim 8, characterized in that the sealing section (138) of the slide unit (130), designed to interact with the counter section (146) of the sleeve element (140), is provided in such a way, in particular with an effective surface designed in such a way in combination with the counter section (146) of the sleeve element (140), that the at least one sealing section (138) with the at least a counter section (146) forms a stop for the movable slide unit (130).

10. Valve assembly (100) according to one of the preceding claims, characterized in that the valve assembly (100) has a drive unit (150), preferably an electromagnet, for moving the slide unit (130), preferably for translational movement in a longitudinal direction of the valve assembly (100).

11. Valve assembly (100) according to one of the preceding claims, characterized in that the valve assembly (100) has at least one preloading element (160), in particular a spring element, for preloading the slide unit (130) in a direction of movement of the slide unit.

12. Valve assembly (100) according to claim 10 and / or 11, characterized in that a preloading element (160) of the slide unit (130) is arranged - on the drive unit (150) or - within the main chamber (120) in the area of ​​a longitudinal end of the valve assembly (100), in indirect or direct contact with the slide unit (130).

13. Electro-hydraulic steering system (1000) for a vehicle, in particular a commercial vehicle, with a valve device (100) according to one of the preceding claims.

14. Electro-hydraulic steering system (1000) according to claim 13, characterized in that the steering system (1000) further comprises: - at least one steering gear (1102), in particular a screw steering gear; - at least one first line (1104) through which the steering gear (1102) can be supplied with hydraulic fluid and / or controlled; - at least one second line (1106) through which the steering gear (1102) can be supplied with hydraulic fluid and / or controlled; and - at least one connected to the first line (1104) and / or the second line (1106) connected or connectable valve device (100) according to one of the preceding claims for pressure reduction in the first line (1104) and / or the second line (1106), wherein the valve device (100) is actuated as required, in particular electromagnetically actuated.

15. Vehicle, in particular commercial vehicle, with an electro-hydraulic steering system (1000) and / or a valve device (100) according to one of the preceding claims.

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