Pump device for a vehicle and an electro-hydraulic steering assistance device

Abstract

The invention relates to a pump device (102) for an electro-hydraulic steering assistance device (105) of a vehicle (100), comprising a hydraulic pump (110), a working line (115), a pressure generation device (120), a first control line (125), a pre-pressure line (130), a compensation tank (135), a shut-off valve (140) with a control inlet (145) and a second control line (150). The hydraulic pump (110) is configured for pumping hydraulic oil (155) from a pump chamber (160) to a pump outlet (165) of the hydraulic pump (110). The pressure generation device (120) has a pressure generation inlet (180) and a pressure generation outlet (185), wherein the pressure generation device (120) is configured for generating an outlet pressure, which can be provided on the pressure generation outlet (185), using an inlet pressure acting on the pressure generation inlet (180), the outlet pressure being lower than the inlet pressure. Thereby a pre-pressure can be generated in the pump chamber (160).

Description

Technical Field

[0001] This method relates to a pump device for an electro-hydraulic steering assist device for a vehicle and an electro-hydraulic steering assist device. Background Technology

[0002] Hydraulic Power Steering (HPS) for heavy-duty commercial vehicles includes a power steering unit (Blocklenkung), piping, a pump for hydraulic oil, and a compensation container. The hydraulic pump is continuously driven by an internal combustion engine. Due to the continuous circulation of the hydraulic oil, it is always adequately conditioned and thus continuously heated to ensure thorough heating of the power steering unit. Summary of the Invention

[0003] In this context, the objective of the present invention is to realize an improved pump device and an improved electro-hydraulic steering assist device for vehicles.

[0004] This task is accomplished by a pump device and an electro-hydraulic steering assist device having the features of the independent claims.

[0005] Advantageously, the pump device is capable of generating pre-pressure. By way of example only, the application of the pump device is particularly evident in the electro-hydraulic steering systems of vehicles. The advantage achievable with the proposed solution is that it enables a pump device, for example, for use in conjunction with an electro-hydraulic steering assist device that operates independently of the internal combustion engine and also converts system pressure into pre-pressure for the temporary action of the hydraulic tank.

[0006] A pump unit, such as an electro-hydraulic steering assist device for a vehicle, includes a hydraulic pump, a working line, a pressure generating device, a first control line, a pre-pressure line, a compensation tank, a shut-off valve with a control inlet, and a second control line. The hydraulic pump is configured to pump hydraulic oil from a pump chamber to the pump outlet. The working line is configured to direct the hydraulic oil to a consumable device, such as a steering mechanism, wherein a working connector of the working line is fluidly connected to the pump outlet. The pressure generating device has a pressure generating inlet and a pressure generating outlet, wherein the pressure generating device is configured to generate an outlet pressure that can be provided at the pressure generating outlet, which is lower than the inlet pressure, when using an inlet pressure acting on the pressure generating inlet. The first control line fluidly connects the pump outlet to the pressure generating inlet. The pre-pressure line fluidly connects the pressure generating outlet to the pump chamber. In this way, the outlet pressure that the pressure generating device can provide at the pressure generating outlet can be used to increase the pressure in the pump chamber. The compensation tank is configured to store hydraulic oil. The shut-off valve is configured to occupy either an open or closed position based on the pressure acting on its control inlet. In the open position, the shut-off valve fluidly connects the compensation tank to the pump chamber, and in the closed position, it disconnects the compensation tank from the pump chamber. A second control line fluidly connects the pump outlet to the control inlet. Therefore, when using a pressure generating device, the pressure of the hydraulic oil in the pump chamber can be increased. This allows for the generation of pre-pressure for the hydraulic pump.

[0007] Corresponding electro-hydraulic steering assist devices can be used for steering in commercial vehicles, such as those with axle loads up to 8 tons. These steering assist devices are equipped with so-called "EPS" (Electronic Power Steering) steering assist devices based on electro-hydraulic principles. This type of EPS steering device is characterized by discontinuous operation; the hydraulic oil in the steering system's hydraulic circuit is only pumped by the pump unit during steering movements, according to the "power on demand" principle. When not steering, the hydraulic oil remains stationary, as does the motor-pump unit consisting of the hydraulic pump and its actuator. Such steering assist devices can be used as "power on demand" steering systems, for example in electrified commercial vehicles without internal combustion engines, or for automating driving requirements autonomously without driver intervention, for example through driver assistance systems such as DAS / ADAS (Levels 1-2) and HAD (Levels 3-5). Studies have shown that operating the steering assist device with hydraulic oil can be advantageous, as the hydraulic oil already maintains a very high pressure level in the tank, for example, greater than atmospheric pressure. Therefore, the electro-hydraulic steering assist device proposed here can advantageously convert the system pressure generated by the hydraulic pump into a pre-pressure for the temporary action of the compensation box.

[0008] The first control line and the additional or alternative second control line of the pump unit can be, for example, a blind line (Sackleitung). The shut-off valve may have a return spring configured to move the shut-off valve to the valve open position when the pressure at the control inlet is below a threshold. Therefore, when the pressure drops below the threshold, the fluid connection between the compensation tank and the pump chamber can be established at any time, and additionally or alternatively, when the pressure is equal to or exceeds the threshold, for example during high-pressure phases, the fluid connection is immediately disconnected.

[0009] According to one embodiment, the pump assembly may also have a pump chamber in which a hydraulic pump is received. The pump chamber may also be configured to receive a drive for driving the hydraulic pump. The pump assembly may also include such a drive configured to drive the hydraulic pump. The drive may have an electric motor and may be additionally or alternatively arranged in the pump chamber. The pump chamber may also be configured to be bubble-free. This allows for the decoupling of the pump drive from other drives, such as vehicle drives.

[0010] The working line may have a first branch leading to the first control line and additionally or alternatively a second branch leading to the second control line. The second branch may be arranged between the pump outlet and the first branch. Therefore, the first control line and the additionally or alternatively second control line may be directly connected to the working line, for example, directly without any other components that are coupled in between.

[0011] The pressure generating device may, for example, have two pistons. To generate pressure, the two pistons may have different diameters.

[0012] Furthermore, it is advantageous that the pressure generating device is configured to generate an outlet pressure, higher than atmospheric pressure, that can be provided at the pressure generating outlet when using the inlet pressure acting on the pressure generating inlet. In this way, the pressure of the hydraulic oil in the pump chamber can be regulated to a value higher than atmospheric pressure.

[0013] The corresponding electro-hydraulic steering assist device for a vehicle has the aforementioned pump device and a consumable device in the form of an electro-hydraulic steering transmission. The electro-hydraulic steering transmission is fluidly connected to a working line. The steering transmission can be a power steering device connected to or capable of being connected to a steering wheel. The steering transmission can have at least one or two working chambers, wherein at least one working chamber is adapted to move a piston coupled to the steering tie rod of the steering device in one direction. An optional second working chamber can be adapted to move the piston coupled to the steering tie rod of the steering device in the opposite direction. Thus, a complete steering system is achieved.

[0014] According to one embodiment, the steering assist device may further include a control device configured to output an activation signal in response to a steering input signal representing the operation of the vehicle's steering wheel, the activation signal being configured to activate the hydraulic pump and, additionally or alternatively, to output a deactivation signal in response to a steering stationary signal representing the stationary state of the vehicle's steering wheel, the deactivation signal being configured to deactivate the hydraulic pump. Therefore, the steering assist device can achieve the principle of "power on demand," meaning that the hydraulic pump is activated only when steering input occurs for steering assistance. Attached Figure Description

[0015] The embodiments of the proposed scheme are described in detail below with reference to the accompanying drawings.

[0016] The attached diagram shows:

[0017] Figure 1 : A schematic diagram of a pump device for a vehicle having an electro-hydraulic steering assist device according to one embodiment;

[0018] Figure 2 A schematic diagram of a pump device according to one embodiment;

[0019] Figure 3 A schematic diagram of an electro-hydraulic steering assist device according to one embodiment; and

[0020] Figure 4 : A schematic perspective view of an electro-hydraulic steering assist device according to one embodiment.

[0021] In the following description of advantageous embodiments of the invention, the same or similar reference numerals are used for elements shown in different figures and those with similar functions, wherein repeated descriptions of these elements are omitted. Detailed Implementation

[0022] Figure 1 A schematic diagram of a vehicle 100 having a pump device 102 for an electro-hydraulic steering assist device 105 is shown according to one embodiment. The pump device 102 includes a pre-pressure unit and, according to this embodiment, is part of the electro-hydraulic steering assist device 105. The use of the pump device 102 in conjunction with the steering system of the vehicle 100 is only exemplarily chosen here. The pump device 102 can also be used in other application areas, and even outside the vehicle field, to provide working pressure.

[0023] Regarding an embodiment of the electro-hydraulic steering assist device 105, Figure 1 Only a portion is shown to illustrate the principle of the pre-pressure unit of pump assembly 102. Therefore, only a part of the hydraulic circuit diagram is shown below, based on... Figure 3 The corresponding complete hydraulic system of the steering assist device 105 is shown.

[0024] By way of example only, according to this embodiment, the electro-hydraulic steering assist device 105 is received on or in a vehicle 100, which, according to this embodiment, is a commercial vehicle configuration, for example, having an axle load of up to 8 tons. According to one embodiment, the vehicle 100 is an electrified or highly automated vehicle. Alternatively, the pump device 102 may be installed in other types of vehicles, machines, or equipment.

[0025] Pump assembly 102 includes a hydraulic pump 110, a working line 115, a pressure generating device 120, a first control line 125, a pre-pressure line 130, a compensation tank 135, a shut-off valve 140 with a control inlet 145, and a second control line 150. The compensation tank 135 includes an air-filled reservoir to allow for thermal expansion. Optionally, an oil level indicator is coupled to the compensation tank. The hydraulic pump 110 is configured to pump hydraulic oil 155 from a pump chamber 160 to a pump outlet 165. The working line 115 is configured to direct hydraulic oil 155 to a consumption device 170, wherein a working connector 175 of the working line 115 is fluidly connected to the pump outlet 165. As an example only, the consumption device 170 is implemented as a steering system of a vehicle 100. The steering system includes, for example, an electro-hydraulic steering transmission. The pressure generating device 120 is used for oil pre-pressure generation. The pressure generating device 120 has a pressure generating inlet 180 and a pressure generating outlet 185. A first control line 125 fluidly connects the pump outlet 165 to the pressure generating inlet 180. A pre-pressure line 130 fluidly connects the pressure generating outlet 185 to the pump chamber 160. The pressure at the pressure generating inlet 180 serves as an actuator to preload the hydraulic oil in the chamber 160 when using the pressure generating device 120. There is no connection between the pressure generating inlet 180 and the pressure generating outlet 185, except for possible leakage. According to one embodiment, the pressure generating device 120 has a stepped piston that serves as a transmission mechanism to reduce the pressure acting on the pressure generating inlet 180 to a significantly lower pressure at the pressure generating outlet 185. According to one embodiment, the pressure generating device 120 is designed as a pressure transducer that uses the high inlet pressure generated by the hydraulic pump 110 during operation of the hydraulic pump 110 and acting on the pressure generating inlet 180 to provide a low outlet pressure at the pressure generating outlet 185. According to one embodiment, the pressure generating device 120 is designed such that the outlet pressure provided at the pressure generating outlet 185 is lower than the high inlet pressure acting at the pressure generating inlet 180, but higher than atmospheric pressure.

[0026] According to one embodiment, the pressure generating device 120 has a first chamber connected to a pressure generating inlet 180 and a second chamber connected to a pressure generating outlet 185. The two chambers are separated from each other by a double piston having a smaller piston face on the first chamber side than on the second chamber side.

[0027] According to one embodiment, a return spring is arranged in the second chamber for the reset of the dual pistons.

[0028] The compensation tank 135 is configured to store hydraulic oil 155. The shut-off valve 140 is configured to occupy either an open position 190 or a closed position based on the pressure acting on its control inlet 145, wherein the shut-off valve 140 fluidly connects the compensation tank 135 to the pump chamber 160 in the open position 190 and fluidly disconnects the compensation tank 135 from the pump chamber 160 in the closed position. A second control line 150 fluidly connects the pump outlet 165 to the control inlet 145.

[0029] According to this embodiment, the steering assist device 105 also includes a pump chamber 160, a driver 192 for driving the hydraulic pump 110, and / or a control device 193.

[0030] According to this embodiment, a hydraulic pump 110 and / or a actuator 192 are received in a pump chamber 160. According to this embodiment, the actuator 192 has an electric motor or is implemented as an electric motor. Furthermore, according to this embodiment, the pump chamber 160 is configured to be bubble-free. According to this embodiment, a consumable device 170 is fluidly connected to a working line 115. According to this embodiment, the consumable device 170 is, for example, a power steering device connected to or capable of being connected to a steering wheel 194 of the vehicle 100. According to one embodiment, the consumable device 170 has at least one working chamber that can be pressurized via the working line 115. According to this embodiment, at least one working chamber is used to move a piston capable of coupling with a steering tie rod. Hereinafter, at least one working chamber is also referred to as a working chamber. According to one embodiment, the steering wheel 194 is part of a steering assist device 105. In a fully automated vehicle, the steering wheel 194 can be deactivated if necessary.

[0031] According to this embodiment, the working conduit 115 has a first branch 196 leading to the first control conduit 125 and / or a second branch 197 leading to the second control conduit 150. According to this embodiment, the second branch 197 is arranged between the pump outlet 165 and the first branch 196. According to this embodiment, the first control conduit 125 and / or the second control conduit 150 are blind conduits.

[0032] According to this embodiment, the shut-off valve 140 has a return spring 199 configured to move the shut-off valve 140 to the valve open position 190 shown herein when the pressure at the control inlet 145 is below a threshold.

[0033] According to this embodiment, the pressure generating device 120 has two pistons. In order to generate pressure at the pressure generating outlet 185, according to this embodiment, the two pistons have different diameters at their opposite ends. According to this embodiment, the pressure generating device 120 is configured to use the pressure of hydraulic oil 155 acting at the pressure generating inlet 180 to regulate the pressure present at the pressure generating outlet 185 to a value exceeding atmospheric pressure.

[0034] The control device 193 is configured, for example, to output an activation signal in response to a steering operation signal representing a steering requirement of the steering or steering control device of the steering wheel 194, the activation signal being configured to activate the drive 192 and / or the hydraulic pump 110, and / or to output a deactivation signal in response to a steering stationary signal representing a stationary state of the steering wheel 194, the deactivation signal being configured to deactivate the drive 192 and / or the hydraulic pump 110.

[0035] The steering assist device 105 proposed herein realizes a preload system for an "electronic power steering" steering transmission device, or "EPS steering transmission device" for short, which is used in electro-hydraulic systems.

[0036] The EPS steering assist device 105 follows a fully integrated plug-and-play solution. Here, the hydraulic oil circuit is decoupled from the vehicle drive, such as the internal combustion engine or electric motor of vehicle 100, and is mounted as a compact drive unit to the power steering device.

[0037] Studies have shown that operating the steering assist device with hydraulic oil 155, which already maintains a pressure level greater than atmospheric pressure in the tank, can be advantageous. The proposed steering assist device 105 is capable of converting the system pressure generated by the hydraulic pump 110 into a pre-pressure to compensate for the temporary effects of the tank 135. This ensures that the hydraulic oil 155 can continue to expand freely, for example, due to temperature effects. The proposed solution enables the generation of pre-pressure without requiring an additional device with an installed steering assist pump.

[0038] exist Figure 1The diagram shows the stationary position without the pumping activity of hydraulic pump 110, in which the chambers of pump chamber 160 and compensation tank 135 are connected. Pre-pressure generation for the working chamber is schematically shown. A working line 115 supplies hydraulic oil 155 to the working chamber. Additionally, two control lines 125 and 150 are present. The first control line 125 measures hydraulic pressure in a blind line and generates a pressure above atmospheric pressure via a double piston of different diameters. This pressure is generated because a pre-pressure line 130 is directly mounted to the large cylinder side of the double piston, which leads to an airless pump chamber 160, also referred to as the "motor chamber." According to this embodiment, the second control line 150 is also implemented as a blind line and a control valve 140 is used such that, during the high-pressure phase, one of the two working chambers isolates compensation tank 135 from pump chamber 160. This isolation allows hydraulic oil, which is considered incompressible at low pressure, to be compressed without (significant) volume reduction.

[0039] Figure 2 A schematic diagram of a pump assembly 102 according to one embodiment is shown. Here, it can be... Figure 1 The pump assembly 102 described herein. According to this embodiment, a shut-off valve 140 of the pump assembly is shown in the valve closed position 200.

[0040] When the pump unit 102 is used in conjunction with the steering device, as according to Figure 1 and Figure 3 As shown, the pump unit 102 constitutes only one of the two pre-pressure units and a part of the entire system.

[0041] In conjunction with the steering mechanism, according to Figure 2 The steering process is now described. The pumping action of hydraulic pump 110 causes a temporary disengagement and generates pre-pressure. Shut-off valve 140 is used when the pressure in steering assist device 105 is low, such as in… Figure 1 The valve 140 is opened as shown, thus enabling the possibility of compensation for the freely flowing volume of oil. If pre-pressure is generated, valve 140 closes and temporarily completely isolates pump chamber 160 from compensation tank 135, also known as compensation container. Pump 110 can replenish the pre-loaded hydraulic oil as needed. In the shut-off valve 140, control line 150 inhibits return spring 199, causing valve 140 to close as shown here. If the pressure in the second control line 150 drops, return spring 199 resets valve 140. Pre-loading allows pump 110 to fill its pump volume more quickly without the dangers of interrupted oil flow on the suction side of pump 110 and damage to pump 110, such as cavitation or aeration.

[0042] exist Figure 2The pressure generating device 120 shows a double piston 220 and a return spring 222 for resetting the double piston 220.

[0043] Figure 3 A schematic diagram of an electro-hydraulic steering assist device 105 according to one embodiment is shown. Here, it can be according to... Figure 1 An embodiment of the described steering assist device.

[0044] Pump unit 102, in addition to being based on Figure 1 In addition to the described features, it also includes an additional working line 315, an additional pressure generating device 320, an additional first control line 325, and an additional pre-pressure line 330. The shut-off valve 140 has an additional control inlet 345 coupled to an additional second control line 350. The hydraulic pump 110 is implemented as controllable, for example, having two directions of rotation. The hydraulic pump 110 is configured to pump hydraulic oil 155 from the pump chamber 160 to the pump outlet 165 in a first operating state, for example, in the first direction of rotation, and to pump hydraulic oil from the pump chamber 160 to an additional pump outlet 365 in a second operating state, for example, in the second direction of rotation.

[0045] The additional working line 315 is configured to guide hydraulic oil to the consumption device 170, wherein an additional working connector 375 of the additional working line 315 is fluidly connected to an additional pump outlet 365. An additional pressure generating device 320, corresponding to pressure generating device 120, is used for pre-pressure generation. The additional pressure generating device 320 has an additional pressure generating inlet 380 and an additional pressure generating outlet 385. An additional first control line 325 fluidly connects the additional pump outlet 365 to the additional pressure generating inlet 380. An additional pre-pressure line 330 fluidly connects the additional pressure generating outlet 385 to the pump chamber 160.

[0046] According to one embodiment, an additional pressure generating device 320 corresponds to the configuration of pressure generating device 120, such that the pressure at the additional pressure generating inlet 380 is used as an actuator to preload the hydraulic oil in the working chamber 160 when the additional pressure generating device 320 is used.

[0047] Figure 4 A perspective view of an electro-hydraulic steering assist device 105 according to one embodiment is shown. Here, it can be in... Figure 1 or Figure 2 An embodiment of the electro-hydraulic steering assist device 105 described herein.

[0048] The EPS steering assist device 105 follows a fully integrated plug-and-play solution. Here, the hydraulic oil circuit is decoupled from the internal combustion engine or electric motor of the vehicle 100 and is mounted as a compact drive unit 400 on the steering device 170, which is in the form of a power steering device.

[0049] List of reference numerals

[0050] 100 vehicles

[0051] 102 Pump Unit

[0052] 105 Electro-hydraulic steering assist device

[0053] 110 Hydraulic Pump

[0054] 115 Working Pipeline

[0055] 120 Pressure Generating Device

[0056] 125 First control line

[0057] 130 pre-pressure pipeline

[0058] 135 Compensation Box

[0059] 140 shut-off valve

[0060] 145 Control Entry

[0061] 150 Second control line

[0062] 155 hydraulic oil

[0063] 160 Pump Room

[0064] 165 Pump Outlet

[0065] 170 Consumable Device

[0066] 175 Working Connector

[0067] 180 Pressure generation inlet

[0068] 185 Pressure generation outlet

[0069] 190 Valve open position

[0070] 192 drives

[0071] 193 Control device

[0072] 194 Steering Wheel

[0073] 196 First Branch

[0074] 197 Second Branch

[0075] 199 Return Spring

[0076] 200 Valve closed position

[0077] 220 Dual Piston

[0078] 222 Return Spring

[0079] 315 Other working pipelines

[0080] 320 Additional pressure generating device

[0081] 325 Another first control line

[0082] 330 Additional pre-pressure piping

[0083] 345 Other control entry points

[0084] 350 Additional second control line

[0085] 365 Other pump outlets

[0086] 375 Other working connectors

[0087] 380 Additional pressure is generated at the inlet

[0088] 385 Additional pressure generates an outlet

[0089] 392 First Working Chamber

[0090] 394 Second Working Chamber

[0091] 396 Steering tie rod

[0092] 398 Piston

[0093] 400 drive units

Claims

1. A pump device (102) for an electro-hydraulic steering assist device (105) for a vehicle (100), wherein, The pump device (102) has the following characteristics: A hydraulic pump (110) configured to pump hydraulic oil (155) from a pump chamber (160) to a pump outlet (165) of the hydraulic pump (110). A working line (115) is provided for guiding hydraulic oil (155) to a consumable device (170), wherein the working connector (175) of the working line (115) is fluidly connected to the pump outlet (165). A pressure generating device (120) has a pressure generating inlet (180) and a pressure generating outlet (185), wherein the pressure generating device (120) is configured to generate an outlet pressure that can be provided at the pressure generating outlet (185) when using an inlet pressure acting on the pressure generating inlet (180), the outlet pressure being lower than the inlet pressure. A first control line (125) fluidly connects the pump outlet (165) to the pressure generating inlet (180). A pre-pressure line (130) fluidly connects the pressure generating outlet (185) to the pump chamber (160) to increase the pressure of the hydraulic oil (155) in the pump chamber (160). Compensation tank (135) for hydraulic oil (155), A shut-off valve (140) having a control inlet (145), wherein the shut-off valve (140) occupies either an open position (190) or a closed position (200) depending on the pressure acting on the control inlet (145), wherein the shut-off valve (140) fluidly connects the compensation tank (135) to the pump chamber (160) in the open position (190) and fluidly separates the compensation tank (135) from the pump chamber (160) in the closed position (200), and A second control line (150) fluidly connects the pump outlet (165) to the control inlet (145).

2. The pump device (102) according to claim 1, wherein the shut-off valve (140) has a return spring (199) configured to move the shut-off valve (140) to the valve open position (190) when the pressure at the control inlet (145) is below a threshold.

3. The pump device (102) according to any one of the preceding claims has a pump chamber (160) in which a hydraulic pump (110) is received.

4. The pump device (102) according to any one of the preceding claims has a steering device (170) which is fluidly connected to the working line (115).

5. The pump device (102) according to any one of the preceding claims has a driver (192) configured to drive the hydraulic pump (110).

6. The pump device according to claim 5, wherein the driver (192) has an electric motor and / or is arranged in the pump chamber (160).

7. The pump device (102) according to any one of the preceding claims, wherein the working line (115) has a first branch (196) leading to the first control line (125) and / or has a second branch (197) leading to the second control line (150).

8. The pump device (102) according to any one of the preceding claims, wherein the pressure generating device (120) has a double piston (220).

9. The pump device (102) according to any one of the preceding claims, wherein the pressure generating device (120) is configured to generate an outlet pressure that can be provided at the pressure generating outlet (185) when using an inlet pressure acting on the pressure generating inlet (180), the outlet pressure being higher than atmospheric pressure.

10. The pump device according to any one of the preceding claims, wherein the hydraulic pump (110) is configured to controllably pump hydraulic oil (155) from the pump chamber (160) to the pump outlet (165) or another pump outlet (365) of the hydraulic pump (110), and wherein, The pump device has the following additional features: An additional working line (315) is used to guide hydraulic oil (155) to the consumption device (170), wherein an additional working connector (375) of the additional working line (315) is fluidly connected to the additional pump outlet (365). An additional pressure generating device (320) has an additional pressure generating inlet (380) and an additional pressure generating outlet (385), wherein the additional pressure generating device (320) is configured to generate an additional outlet pressure that can be provided at the additional pressure generating outlet (385) when using an additional inlet pressure acting on the additional pressure generating inlet (380), the additional outlet pressure being lower than the additional inlet pressure. An additional first control line (325) fluidly connects the additional pump outlet (365) to the additional pressure generating inlet (380). An additional pre-pressure line (330) fluidly connects the pressure generating outlet (385) to the pump chamber (160) to increase the pressure of the hydraulic oil (155) in the pump chamber (160). An additional second control line (350) fluidly connects the additional pump outlet (365) to an additional control inlet (345) of the shut-off valve (140), wherein the shut-off valve (140) occupies either the valve open position (190) or the valve closed position (200) depending on the pressure acting on the additional control inlet (345).

11. An electro-hydraulic steering assist device (105) for a vehicle (100), wherein, The steering assist device (105) has a pump device (102) according to any one of the preceding claims and a consumable device (170) in the form of an electro-hydraulic steering rotation device.

12. The steering assist device (105) according to claim 11, having a control device (193) configured to output an activation signal in response to a steering operation signal representing the operation of a steering wheel (194) of the vehicle (100), the activation signal being configured to activate the hydraulic pump (110), and / or to output a deactivation signal in response to a steering stationary signal representing the stationary state of the steering wheel of the vehicle (100), the deactivation signal being configured to deactivate the hydraulic pump (110).

Images