Adjustable single-stroke vane pump, method for operating a pump, system for generating a pressure medium flow, and steering system

Abstract

The invention relates to an adjustable single-stroke vane pump (1) for generating a pressure medium flow for a consumer (2), the vane pump comprising: a pump housing (3) in which an adjustable cam ring (4) is inserted; and a rotor (5) and a drive shaft (6) which can be rotated within the cam ring (4). The rotor (5) carries vanes (7) that form working chambers (8) between the rotor (5) and the cam ring (4). A suction connection (9) and a pressure connection (10) for a pressure medium are provided between the rotor (5) and the cam ring (4). Furthermore, an actuator (17) is provided for changing the eccentricity of the cam ring (4) relative to the rotor (5). The actuator (17) is designed such that the eccentricity of the cam ring (4) can be adjusted at least between a positive eccentricity and an eccentricity of zero. At a positive eccentricity, the cam ring (4) is displaced from an eccentricity of zero in a positive direction in such a way that, when the rotor (5) rotates in a first rotational direction (18), the pressure medium flows into the working chambers (8) through the suction connection (9) and exits through the pressure connection (10). At an eccentricity of zero, pressure medium is not delivered to the consumer (2) when the rotor (5) rotates. The drive shaft (6) is designed and configured to be driven by an output shaft (105) of a vehicle gearbox (4).

Description

[0001] Adjustable, single-stroke vane pump, method for operating a vane pump, system for generating a pressure medium flow and steering system

[0002] This application claims priority from German patent application No. 10 2023 134 124.3, the contents of which are incorporated herein by reference.

[0003] The invention relates to an adjustable, single-stroke vane pump for generating a pressure medium flow for a consumer according to the preamble of claim 1.

[0004] The invention further relates to a method for operating an adjustable, single-stroke vane pump for generating a pressure medium flow for a consumer.

[0005] Furthermore, the invention relates to a computer program product.

[0006] The invention also relates to a system for generating a pressure medium flow for a consumer.

[0007] The invention also relates to a steering system of a vehicle.

[0008] Pumps are known from the state of the art which have one or more rotors for conveying a fluid. These can include rotary displacement pumps (rotary lobe pumps, rotary piston pumps, gear pumps, rotary vane pumps, vane pumps), radial piston pumps or centrifugal pumps.

[0009] Unidirectional pumps, i.e., pumps that deliver a pressure medium in only one direction of rotation and thus generate a pressure medium flow in one direction of flow for a consumer, are particularly well known in the art. However, bidirectional pumps are also known, which allow the direction of rotation to be reversed, so that a pressure medium can be delivered in two directions. The known bidirectional pumps used in practice generally employ the "gear pump" or "axial piston pump" principle.

[0010] Conventional vane pumps usually pump hydraulic fluid in only one direction of rotation of the vane pump rotor.

[0011] Vane pumps can be designed either as fixed-displacement pumps, i.e., with a constant geometric displacement, or with an adjustable displacement, i.e., with a variable geometric displacement, so that the pumped volume of the pressure medium can be adjusted between a maximum and a minimum flow rate. Both vane pumps with a constant geometric displacement and vane pumps with a variable geometric displacement can have a cam ring, which is non-adjustable in the first case and adjustable in the second case, as shown below. Adjustable cam rings are well known in the art.

[0012] The term "geometric displacement" is generally used to describe the volume delivered per revolution of a vane pump. For adjustable vane pumps, the geometric displacement depends on the eccentricity between the rotor and the cam ring, and thus on the size of the working chambers or cells.

[0013] Vane pumps with adjustable displacement, which are often also referred to as variable displacement pumps, are usually constructed as follows. A pump housing essentially contains a cam ring or a stroke contour ring and a rotatably mounted rotor. The rotor has radial slots in which vanes are arranged so that they can be radially displaced and are positively guided by the slots. During operation of the vane pump, the vanes slide with their outer ends against the inner wall of the cam ring, thereby pumping a pressure medium or hydraulic fluid (e.g., pressure oil). In contrast to pumps with a constant displacement (fixed displacement pumps), pumps with a variable displacement can prevent an overproduction of hydraulic fluid, particularly at high speeds, which in fixed displacement pumps must be partially compensated for, for example, by bypass circulation.Therefore, in fixed displacement pumps in the higher speed range, mechanically unusable energy is consumed by the bypass circulation, which equates to unnecessary heat or energy loss. To regulate the delivery volume, in particular to reduce the delivery volume as the rotor speed increases, the eccentricity of the cam ring relative to the rotor is changed, in particular reduced. For this purpose, a conventional vane pump has a control device (e.g. a flow control valve) with two outputs, which can each supply a portion of the delivered hydraulic fluid to a left or right pressure chamber via control channels. The pressure chambers act from the left or right onto the outer surface of the cam ring and thus bring about the desired change in the eccentricity of the cam ring relative to the rotor.

[0014] A vane pump of the type mentioned above is known, for example, from DE 10 2004 060 082 A1.

[0015] Such a vane pump is also known from DE 10 2014 105 613 A1, in which particular reference is made to Figures 1 to 3 of this document to illustrate the structure of a conventional vane pump.

[0016] For further information on the state of the art, please refer to DE 10 2014 115 159 A1.

[0017] The geometric delivery volume of the vane pump is controlled, as shown above, by hydraulically adjusting the stroke or eccentricity between the cam ring and the rotor. In addition, a return spring is often used to load the cam ring with a compressive force that pushes the cam ring in a direction or into a position that corresponds to the maximum delivery volume. The aim of this is to ensure that, in the absence of hydraulic pressure, the cam ring is in a position in which the geometric delivery volume is maximum. Conventional vane pumps cannot usually be brought to a so-called zero eccentricity, where the center axes of the cam ring and the rotor run coaxially, because in this position the pressure cannot be adjusted due to the lack of pressure medium flow or the rotor.Due to the lack of pressure in the pressure medium flow, the adjustment can no longer be controlled and the zero eccentricity can therefore no longer be eliminated in a pressure-dependent manner using a flow control valve.

[0018] DE 10 2015 107 543 A1 describes a vane pump for delivering a fluid to a consumer of a steering system. Its direction of rotation is reversible and it is not necessary to provide a control valve to regulate the volume flow of the vane pump. However, it essentially describes a vane pump with a constant geometric displacement. A vane pump with a variable geometric displacement is also mentioned, but is not illustrated or described in detail.

[0019] DE 10 2014 221 447 A1 discloses a vane pump for an automatic transmission in motor vehicles. The cam ring can be pivoted about a pivot bearing relative to the pump housing and the rotor, resulting in a variable displacement. Maximum eccentricity of the cam ring relative to the rotor axis results in a maximum displacement, whereas a non-eccentric relative position of the cam ring and rotor results in zero displacement. Between these two extreme positions, i.e., minimum and maximum eccentricity, intermediate positions and thus different displacements are possible.

[0020] DE 103 37 653 A1 discloses a vane pump for a motor vehicle steering system. It is disclosed that the flow rate can be continuously adjusted, whereby in the neutral center position (zero eccentricity) at zero flow, only the pump's friction needs to be overcome. This is intended to result in low-loss standby operation. The use of the vane pump in conjunction with a drive by an electric motor or the vehicle's engine is disclosed.

[0021] The present invention is based on the object of further developing an adjustable, single-stroke vane pump for generating a pressure medium flow for a consumer, in particular in order to expand its possible applications.

[0022] This object is achieved by an adjustable, single-stroke vane pump according to claim 1.

[0023] The present invention is further based on the object of providing a method for operating an adjustable, single-stroke vane pump for generating a pressure medium flow for a consumer, which method expands the possible applications of the vane pump. This object is achieved by a method according to claim 17.

[0024] The present invention further relates to the object of providing an advantageous computer program product for a vane pump or for operating a vane pump.

[0025] This problem is solved by claim 25.

[0026] The present invention is further based on the object of providing an advantageous system for generating a pressure medium flow for a consumer.

[0027] This object is achieved by a system according to claim 26.

[0028] The present invention is further based on the object of providing a steering system for a vehicle which is supplied with pressure medium in a particularly advantageous, in particular simple, safe and energy-saving manner.

[0029] This object is achieved by a steering system according to claim 29.

[0030] The adjustable, single-stroke vane pump according to the invention serves to generate or deliver a pressure medium flow for a consumer. The vane pump has a pump housing in which an adjustable cam ring is inserted. The vane pump further comprises a rotor and a drive shaft that are rotatable within the cam ring. The rotor carries vanes that form working chambers between the rotor and the cam ring. A suction port and a pressure port for a pressure medium are formed between the rotor and the cam ring. Furthermore, an adjusting device is provided for changing the eccentricity of the cam ring relative to the rotor.According to the invention, the adjusting device is designed such that an adjustment of the eccentricity of the cam ring is possible at least between a positive eccentricity and a zero eccentricity, wherein at the positive eccentricity the cam ring is shifted from the zero eccentricity in a positive direction such that when the rotor rotates in a first direction of rotation the pressure medium flows into the working chambers through the suction connection and flows out through the pressure connection. According to the invention, at the zero eccentricity no pressure medium is delivered to the consumer when the rotor rotates. Furthermore, according to the invention, the drive shaft is designed and configured for drive by an output shaft of a vehicle transmission.

[0031] The vane pump according to the invention can be used in applications that are not feasible with a conventional adjustable vane pump. This makes the vane pump according to the invention particularly advantageous as a power steering pump or as an emergency power steering pump. By actively adjusting the cam ring position relative to the rotor to zero eccentricity, the delivery characteristics can be adjusted during or in advance of the vane pump operation so that the vane pump can be operated in a state in which no delivery is taking place.

[0032] If no active adjustment takes place, the vane pump preferably delivers a speed-dependent constant volume flow in the manner known from the prior art, in particular in vane pumps in which a flow control valve is used.

[0033] The vane pump according to the invention can have a cam ring that is actively adjustable independently of the speed and / or direction of rotation of the rotor and / or a stop for the cam ring that is actively adjustable independently of the speed and / or direction of rotation of the rotor for variably adjusting the stroke of the vane pump down to zero delivery (zero eccentricity). This can be done during operation of the vane pump or when it is at a standstill.

[0034] This allows the following operating mode to be implemented: By actively adjusting the cam ring to zero eccentricity relative to the rotor, the vane pump can be avoided, regardless of the direction of rotation and speed, and energy consumption can be reduced, as no pressure fluid is pumped. As a result, additional components, such as couplings, for shutting down the unit can be avoided.

[0035] The possibility provided according to the invention of setting a zero eccentricity of the cam ring relative to the rotor makes it possible in a particularly advantageous manner to have the vane pump driven by the output shaft of the vehicle transmission.

[0036] The output shaft of the vehicle's transmission may be stationary or rotating in the opposite direction when the vehicle is moving forward rather than forward. If the output shaft of the vehicle's transmission is used to drive the rotor's drive shaft or the rotor, this would cause the rotor to rotate in a second direction of rotation opposite to the first. The volumetric flow would therefore be transported in the opposite direction, i.e. flowing out of the working chambers through the suction port. This can be avoided by setting a zero eccentricity when the rotor rotates in the second direction of rotation. Alternatively, a freewheel could be used so that the rotor does not rotate in the second direction of rotation.

[0037] The invention makes it possible to set a zero eccentricity of the cam ring relative to the rotor as required when the rotor rotates in the first direction of rotation and a pressure medium flow generated by the vane pump is not required (standby operation).

[0038] The zero eccentricity of the cam ring relative to the rotor can be adjusted in particular when a pressure medium flow from the vane pump according to the invention to the consumer is not required, e.g. because no steering movement is to take place or does take place or because the consumer is supplied with pressure medium by another pump, in particular a pump driven by a vehicle engine, in particular by an internal combustion engine, e.g. a main steering pump.

[0039] The adjusting device according to the invention can adjust the positive eccentricity of the cam ring accordingly depending on the needs of the consumer, in particular to support another pump, e.g. a main steering pump, or to take over the supply of the consumer alone, in which case the eccentricity of the cam ring can preferably be adjusted so that on the one hand a sufficient pressure medium flow is available for the respective driving situation, but on the other hand an unnecessarily large pressure medium flow to the consumer is avoided.

[0040] According to the invention, it is provided that the drive shaft or the rotor of the vane pump is driven by the output shaft or an output shaft of the vehicle transmission, ie that the drive shaft is designed and configured to be connected to the output shaft of the vehicle transmission or to be driven by it.

[0041] The vane pump according to the invention is particularly suitable in combination with a main steering pump.

[0042] The main steering pump can preferably be driven by a vehicle engine of a vehicle. In this case, it can be provided that the main steering pump provides the pressure medium flow for the vehicle steering of the vehicle when the vehicle engine, in particular an internal combustion engine, is switched on or running. The main steering pump can be driven in a conventional manner by the vehicle engine, in particular an output shaft of the vehicle engine or a V-belt driven by the vehicle engine. In addition, the use of the vane pump according to the invention can be provided, in particular as a power steering pump or as an emergency power steering pump which is driven by the output shaft of the vehicle transmission. This makes it possible for the vehicle engine to be switched off when the vehicle does not need to be accelerated or driven. In this case, or when the vehicle engine is switched off oris not running, then it is provided by the vane pump according to the invention, preferably in a configuration as a power steering pump or as an emergency power steering pump. The output shaft of the vehicle transmission drives the drive shaft or the rotor of the vane pump according to the invention, which in turn provides the pressure medium flow for the vehicle steering. This means that when the vehicle engine is switched off and the vehicle transmission is rotating, a pressure medium flow can be provided for the vehicle steering. This allows energy to be saved without impairing the vehicle steering. Such a method or switching off the vehicle engine is particularly suitable at a higher vehicle speed, especially when the vehicle is rolling or "sailing" without drive, iewhen the drive motor is switched off during travel, and especially when the vehicle is traveling straight ahead, where only minimal steering movements are necessary anyway. According to the invention, a control device can be provided and configured which controls the actuating device in such a way that the zero eccentricity of the cam ring relative to the rotor can be adjusted independently of the direction of rotation and the speed of the rotor.

[0043] Such an adjustment can be advantageous in particular when the rotor is at a standstill and / or when the rotor rotates in the first direction of rotation, but a pressure medium flow generated by the vane pump is not required, and / or when the rotor rotates in a second direction of rotation which is opposite to the first direction of rotation.

[0044] Because the vane pump according to the invention has a control device which controls the adjusting device in such a way that the adjusting device sets the zero eccentricity of the cam ring relative to the rotor when the rotor is stationary and / or when the rotor rotates in a second direction of rotation, the vane pump according to the invention can be used and operated more universally than the previously known vane pumps.

[0045] The possibility of setting the zero eccentricity even when the rotor rotates in the first direction of rotation makes it possible to save energy when the pressure medium flow is not required or when the consumer is supplied with pressure medium from another source.

[0046] The vane pump can prevent the fluid from being pumped “backwards” when the direction of rotation is changed (from the first direction of rotation to the second direction of rotation), which is not desired for many applications.

[0047] The solution according to the invention also avoids unwanted pressure pulsations.

[0048] According to the invention, it can be provided that the control device controls the actuating device in such a way that when a vehicle is at a standstill and / or when a pressure medium flow generated by the vane cell pump is not required, and / or when a vehicle in which the vane cell pump is installed is reversing, the actuating device sets the zero eccentricity of the cam ring relative to the rotor.

[0049] It has been shown that when the vane pump according to the invention is installed in a vehicle and is driven by the output shaft of the vehicle transmission, it is particularly advantageous if the control device controls the actuating device in such a way that the zero eccentricity of the cam ring is set relative to the rotor when the vehicle is at a standstill and / or when reversing.

[0050] Even when the vehicle is moving forward, setting the zero eccentricity can be advantageous when the pressure medium flow is not required, as this saves energy. The vane pump according to the invention can be used in applications that were not feasible with a conventional adjustable vane pump. Among other things, the vane pump according to the invention can also be set up in applications such as a hydraulic transmission as a power steering pump and / or as an emergency power steering pump. The vane pump according to the invention is particularly suitable for the aforementioned applications. However, the application of the vane pump according to the invention is not limited to the aforementioned examples.

[0051] The solution according to the invention makes it possible to adjust the pumping characteristics during operation of the vane pump or in advance in such a way that various operating modes can be implemented that cannot be achieved with the vane pumps known from the prior art. This will be explained in more detail below, also using the method according to the invention.

[0052] Depending on the setting of the control or regulation, the delivery characteristics of the vane pump according to the invention can be adjusted independently of the operating mode of the drive unit during installation or during operation of a system, in particular a steering system, into which the vane pump is integrated.

[0053] According to the invention, it can be provided that the vane pump, in particular the pump housing and / or the rotor and / or the drive shaft and / or the cam ring are designed or arranged in such a way that the adjusting device can set a positive and a zero eccentricity and possibly even a negative eccentricity, as will be described in more detail below, relative to the rotor.

[0054] An outer ring can be inserted into the pump housing in a generally known manner. In principle, the pump housing of a vane pump can serve as an outer ring (also known as an intermediate ring). However, the design of an outer ring has proven to be more practical for series production. In this configuration, the cam ring is located within the outer ring.

[0055] In a manner also known in principle, the rotor can be provided with slots in which the vanes forming the working chambers are movably arranged. For this purpose, a rear vane fluid pressure is used in a known manner, which essentially acts on the ends of the vanes guided in the slots of the rotor.

[0056] For possible advantageous designs of the vane pump, reference is hereby made to DE 10 2005 043 253 B4.

[0057] The pump housing can be closed using a cover, so that the cam ring is delimited on one end by the cover and on the other end by the pump housing. It can also be provided that an end plate is arranged on the end between the cam ring and the pump housing. Alternatively or additionally, it can also be provided that a cover-side control plate is arranged on the end between the cam ring and the cover. The working chambers can thus be delimited in the axial direction of the rotor by the cover or the cover-side control plate or the pump housing or the end plate. The cover or the cover-side control plate and / or the end plate or the pump housing can have suction or pressure kidneys in a known manner, which can serve to allow pressure medium to flow into or out of the suction connection or the pressure connection.

[0058] Within the scope of the invention, if an outer ring is inserted into the pump housing, this is to be understood as the inner wall of the pump housing, insofar as features refer to this. Furthermore, if features refer to the pump housing or the cover, the control plate or the end plate can be understood as part of the cover or pump housing, insofar as features refer to this.

[0059] The pressure medium is preferably a hydraulic fluid, for example a pressure oil.

[0060] For further advantageous embodiments, reference is also made to DE 10 2015 115 587 A1.

[0061] According to the invention, it can be provided that the adjusting device is designed in such a way that an active adjustment of the eccentricity of the cam ring relative to the rotor is possible independently of and / or in addition to a volume flow-dependent control.

[0062] It has proven particularly advantageous if the actuating device is designed in such a way that an active adjustment of the eccentricity of the cam ring relative to the rotor is possible independently of a volume flow-dependent control, i.e. independently of the pressure of the pressure medium. This makes it possible to set a suitable delivery characteristic. In particular, if required, the cam ring can be set to zero eccentricity relative to the rotor, so that no delivery takes place. Depending on the driving situation, in particular depending on whether a vehicle is reversing or stationary, a suitable position of the cam ring relative to the rotor can be set or this position can be influenced by the active actuator that can be controlled independently of the volume flow.

[0063] In addition to the active adjustment of the eccentricity, a volume flow-dependent control can also be provided, for example using a flow control valve.

[0064] According to the invention, it can further be provided that the adjusting device for adjusting the eccentricity of the cam ring relative to the rotor has at least one active actuator, which acts directly or indirectly on the cam ring and which is controllable independently of the pressure of the pressure medium. It has proven particularly suitable if the adjusting device has at least one active actuator, which is controllable independently of the pressure of the pressure medium. Thus, the eccentricity, in particular also a zero eccentricity, can be adjusted as required. In addition to an optional but preferably provided conventional adjustment or control of the cam ring as a function of the pressure of the pressure medium or the pressure medium flow, the active actuator enables independent control or regulation of the cam ring as a function of freely selectable parameters.

[0065] According to the invention, it can be provided that the adjusting device for adjusting the eccentricity of the cam ring relative to the rotor has at least one active actuator and additionally a flow control valve which influences the eccentricity of the cam ring as a function of a volume of the pressure medium flow from the pressure connection to the consumer.

[0066] This solution has proven to be advantageous in order to realize, in addition to an adjustment using the active actuator, also an adjustment depending on a volume flow of the pressure medium, i.e. an adjustment depending on the pressure of the pressure medium.

[0067] According to the invention, it can alternatively also be provided that the adjusting device for adjusting the eccentricity of the cam ring relative to the rotor has at least one active actuator and no flow control valve which influences the eccentricity of the cam ring as a function of a volume of the pressure medium flow from the pressure connection to the consumer.

[0068] It has proven advantageous for certain applications if, in addition to the at least one active actuator, no flow control valve is provided, i.e. if the eccentricity of the cam ring is not influenced by a flow control valve. In this case, it can be provided that an adjustment of the cam ring by the active actuator takes place in such a way that a speed of the vehicle and / or other parameters are taken into account. It can also be provided that, controlled by the control device for adjusting the eccentricity, a volume flow of the pressure medium flow and / or directly or indirectly the speed of the rotor and / or the drive shaft is taken into account by the active actuator.

[0069] It is advantageous if the at least one active actuator is fixedly connected to the cam ring in such a way that the active actuator can change the eccentricity of the cam ring relative to the rotor in a positive direction and a negative direction, in particular can set both a positive and a zero eccentricity of the cam ring.

[0070] It has proven advantageous if the at least one active actuator, particularly if exactly one active actuator is provided, is firmly or permanently or rigidly connected to the cam ring, preferably in such a way that the connection can only be released if joining means (connecting means) or components are destroyed or damaged. This allows the active actuator to both push and slide the cam ring, so that the actuator can move the cam ring into the desired position. The active actuator can preferably be a control pin, which is preferably firmly or rigidly connected to the cam ring.

[0071] According to the invention, it can further be provided that the actuating device has two actuators, wherein one actuator is connected to the cam ring in such a way that the cam ring can be displaced in a positive direction to change the eccentricity and one actuator is connected to the cam ring in such a way that the cam ring can be displaced in a negative direction to change the eccentricity.

[0072] Configuring the actuating device with two actuators can enable the cam ring to be displaced particularly evenly and reliably relative to the rotor. In this case, one actuator can displace the cam ring in a positive direction, while the other actuator can displace the cam ring in a negative direction. A fixed connection between the actuator and the cam ring is not necessary. Alternatively, each of the actuators can also pull and push, for which purpose a fixed, rigid, or non-detachable connection between the actuator and the cam ring is preferably provided.

[0073] It is advantageous if the actuating device has two active actuators which are suitable for applying opposing forces to the cam ring, or if the actuating device has an active actuator and a passive, non-controllable actuator, preferably a spring, which are suitable for applying opposing forces to the cam ring.

[0074] It has proven particularly suitable for the actuating device to have two active actuators that can apply opposing forces to the cam ring, allowing the cam ring to be adjusted to the desired eccentricity relative to the rotor. The actuators can be permanently connected to the cam ring, if required, or they can be loosely connected to the cam ring, for example, by only touching the cam ring.

[0075] To control the eccentricity of the cam ring, it can also be provided that the actuating device has only one active actuator and an additional passive actuator whose effect on the cam ring cannot be actively controlled. The passive actuator can be, for example, an elastic element or preferably a spring. The targeted or required adjustment of the eccentricity of the cam ring relative to the rotor is carried out by the active actuator, which, depending on the desired adjustment of the cam ring, applies a force that counteracts the force of the passive actuator, applies no force, or applies a force that acts in the same direction as the passive actuator. The passive actuator has the advantage that it can preferably be dimensioned such that the passive actuator shifts the cam ring from a zero eccentricity when the active actuator does not apply any force.Preferably, the passive actuator pushes the cam ring in a positive direction, starting from the zero eccentricity. According to the invention, it can further be provided that the at least one actuating device is a mechanical and / or electrical and / or electromechanical and / or hydraulic and / or pneumatic actuator that can be controlled independently of the pressure of the hydraulic fluid.

[0076] Designing the actuator as a pneumatic and / or mechanical and / or electrical and / or electromechanical actuator has proven particularly suitable for most applications.

[0077] Preferably, the at least one active actuator is designed as a mechanical and / or electromechanical and / or hydraulic and / or pneumatic actuator.

[0078] The adjustment of the eccentricity is preferably carried out by means of an active mechanical and / or electrical and / or electromechanical actuator in that the actuator acts directly on the cam ring.

[0079] The adjustment can be active on one side, preferably with an electromechanical actuator, or active on both sides, preferably with two electromechanical actuators that apply forces acting in opposite directions to the cam ring.

[0080] The adjustment of the eccentricity can also be carried out via a passive actuator, as described above, and an active actuator, which is preferably electromechanically or mechanically or electrically controllable.

[0081] According to the invention, it can further be provided that the adjusting device is designed to adjust the position of a stop against which the cam ring abuts when it has reached one of its end positions, wherein the adjusting device additionally has a passive actuator, preferably a spring, which acts on the cam ring in such a way that the cam ring is loaded with a compressive force in the direction of the stop.

[0082] Adjusting the position of a stop against which the cam ring strikes when it has reached one of its end positions, e.g., a maximum positive eccentricity or a zero eccentricity, has proven suitable for limiting the maximum geometric displacement or defining an end position. In addition, a passive actuator, preferably an elastic element or a spring, can preferably be provided, which applies a compressive force to the cam ring in the direction of the stop.

[0083] It can further be provided that the adjusting device has a stop which limits the maximum positive eccentricity and a stop which defines the zero eccentricity or, as shown below, limits a maximum negative eccentricity, wherein at least one of the stops, preferably both stops, can be adjustable.

[0084] The stops can also be an outer ring, if an outer ring is provided, whose inner wall has a corresponding design so that it acts as a stop. However, the stop can also be a stop element that is independent of the outer ring or the pump inner wall and is preferably firmly connected to the outer ring or the pump housing. The stop can also be designed as an active actuator or connected to an active actuator in such a way that the stop is adjustable. It can be a mechanical and / or electrical and / or electromechanical and / or hydraulic and / or pneumatic actuator or a corresponding stop.

[0085] The stop can be part of the adjusting device.

[0086] According to the invention, it can further be provided that the adjusting device for changing the eccentricity of the cam ring relative to the rotor has a first pressure chamber between an outer side of the cam ring and an inner wall of the pump housing, wherein a pressure in the first pressure chamber applies a compressive force to the cam ring in order to press the cam ring in a positive direction and / or that the adjusting device has a second pressure chamber between an outer side of the cam ring and an inner wall of the pump housing, wherein a pressure in the second pressure chamber applies a compressive force to the cam ring in order to press the cam ring in a negative direction.

[0087] Controlling the cam ring using a first pressure chamber and a second pressure chamber is well known from the prior art, including from the cited prior art documents. The two pressure chambers are supplied with the pressure medium, with the pressure in the first and second pressure chambers preferably being controlled by a flow control valve, which preferably has a high-pressure chamber and a low-pressure chamber. Such control or regulation is generally known. The first pressure chamber is fluidically separated from the second pressure chamber between the outer side of the cam ring and the inner wall of the pump housing or an outer ring (if present), preferably by a sealing means.

[0088] Within the scope of the invention, it can preferably be provided that the actuating device has a first pressure chamber and a second pressure chamber which are pressurised in a known manner for controlling or regulating the eccentricity of the cam ring, wherein this is a volume flow-dependent or speed-dependent control or the control is dependent on the pressure of the pumped pressure medium, i.e. is not independent of this. In addition, at least one active actuator is preferably provided which can be controlled independently of the pressure of the pressure medium or the speed of the drive shaft of the vane pump or the output shaft of the vehicle transmission. The solution according to the invention is not limited to the provision of a first pressure chamber and / or a second pressure chamber which are fluidically connected to the pressure medium which the vane pump pumps for consumption.The first and / or second pressure chambers can also be omitted within the scope of the invention. Furthermore, the first pressure chamber and / or the second pressure chamber can also be controlled with a different pressure medium, independent of the pressure medium that the vane pump delivers to the consumer.

[0089] According to the invention, it can further be provided that the actuating device has a superimposing device in order to superimpose the pressure in the first pressure chamber and / or the second pressure chamber.

[0090] In one embodiment of the invention, it can be provided that the pressure in the first pressure chamber and / or in the second pressure chamber or their hydraulic control is superimposed as required by a superimposing device in order to achieve a targeted adjustment of the eccentricity of the cam ring or a change in the usual control, in particular a displacement of the cam ring that is independent of the pressure of the pressure medium or the speed of the drive shaft of the vane pump or the output shaft of the vehicle transmission or that superimposes the pressure. The superimposing device can, for example, be configured to increase the pressure in one of the pressure chambers and / or decrease it in the other pressure chamber, for example by adjusting the flow control valve by an active actuator or two opposing active actuators or an active actuator and a passive actuator that generate opposing forces.For example, it can be provided that the superposition device acts on a piston of the flow control valve and adjusts its position.

[0091] According to the invention, it can further be provided that the vane pump is designed as a power steering pump and / or as an emergency power steering pump and / or the consumer is a vehicle steering system, in particular a steering cylinder, of a vehicle.

[0092] The vane pump according to the invention has proven particularly suitable for such an application. However, the vane pump is not limited to this use.

[0093] The vane pump according to the invention is particularly suitable for generating a pressure medium flow for a vehicle steering system.

[0094] In one embodiment of the invention, it can further be provided that the adjusting device is designed such that an adjustment of the eccentricity of the cam ring relative to the rotor between the positive eccentricity and a negative eccentricity is possible, wherein in the case of negative eccentricity the cam ring is shifted from the zero eccentricity into a negative direction opposite the positive direction. Because the adjustment of the eccentricity of the cam ring relative to the rotor is possible not only within a positive eccentricity, as was previously the case, but also within a negative eccentricity, the vane pump according to the invention can be used even more universally. Starting from a positive eccentricity, the cam ring can be shifted beyond the zero eccentricity into a negative eccentricity.In this embodiment, the vane pump according to the invention thus makes it possible for the cam ring, starting from a positive eccentricity, to be displaced so far in a negative direction or into a negative eccentricity that the cam ring is moved beyond the zero eccentricity in a direction in which the cam ring has a negative eccentricity relative to the rotor.

[0095] By adjusting the eccentricity from positive to negative eccentricity when the direction of rotation of the rotor changes, the delivery direction of the vane pump can be maintained.

[0096] Within the scope of the invention, it is preferably provided that when the direction of rotation changes, i.e. when the rotor rotates in a second direction of rotation, a zero eccentricity is set, i.e. that no pressure medium is pumped. As already explained, this prevents the pressure medium from being pumped backwards, i.e. the pressure medium flows into the working chambers through the pressure connection and flows out through the suction connection. In one embodiment of the invention, however, it is alternatively also possible for a negative eccentricity of the cam ring relative to the rotor to be set when the rotor rotates in the second direction of rotation. Thus, pressure medium continues to be sucked into the working chambers through the suction connection and flows out of the working chambers through the pressure connection. The connected consumer, preferably a vehicle steering system, can therefore continue to be supplied with pressure medium.This can be advantageous in order to provide a pressure medium flow, in particular for a vehicle steering system, even when the vehicle is moved backwards, i.e. the rotor rotates through the output shaft in the second direction of rotation (opposite to the first direction of rotation which results when the vehicle is moving forwards).

[0097] As explained above, this is in particular an alternative to setting a zero eccentricity when the rotor rotates in a second direction of rotation. Setting a zero eccentricity will be sufficient in most applications and can be implemented more cost-effectively than designing a vane pump in such a way that a negative eccentricity can also be set. In particular, if the vane pump is designed as a power steering pump and / or as an emergency steering pump and a vehicle steering system is primarily supplied with pressure medium by a main steering pump driven by a vehicle engine, zero eccentricity will generally be sufficient when reversing, i.e. when the direction of rotation of the rotor changes, since in this driving situation the vehicle engine, in particular an internal combustion engine, is typically working or running and thus the main steering pump is driven.

[0098] The present invention also relates to a method for operating an adjustable, single-stroke vane pump for generating a pressure medium flow for a consumer. The vane pump operated by the method according to the invention has a pump housing in which an adjustable cam ring is inserted. The vane pump further has a rotor and a drive shaft which are rotatable within the cam ring, wherein the rotor carries vanes which form working chambers between the rotor and the cam ring. A suction connection and a pressure connection for a pressure medium are formed between the rotor and the cam ring. Furthermore, an adjusting device is provided for changing the eccentricity of the cam ring relative to the rotor.

[0099] The method according to the invention provides that the adjusting device enables an adjustment of the eccentricity of the cam ring between a positive and at least one zero eccentricity. To adjust the positive eccentricity, the cam ring is displaced from the zero eccentricity in a positive direction. With a positive eccentricity and a rotation of the rotor in a first direction of rotation, pressure medium flows into the working chamber through the suction port and flows out through the pressure port. According to the invention, when the eccentricity of the cam ring is adjusted to a zero eccentricity, no pressure medium is delivered to the consumer. Furthermore, it is provided that the drive shaft is driven by an output shaft of a vehicle transmission.

[0100] The method according to the invention enables operating modes and applications that could not be implemented in prior art vane pumps.

[0101] According to the invention, it can be provided that the adjusting device sets the zero eccentricity of the cam ring relative to the rotor independently of the direction of rotation and a speed of the rotor.

[0102] According to the invention, it can be provided that the adjusting device sets the zero eccentricity of the cam ring relative to the rotor when the rotor is at a standstill and / or when the rotor rotates in the first direction of rotation but a pressure medium flow is not required, and / or when the rotor rotates in a second direction of rotation which is opposite to the first direction of rotation.

[0103] The vane pump can be placed in a state or operated in a state in which no pumping takes place.

[0104] It is advantageous if the actuating device is controlled in such a way that, when a vehicle is at a standstill and / or when a pressure medium flow generated by the vane pump is not required, and / or when a vehicle in which the vane pump is installed is reversing, the actuating device sets the zero eccentricity of the cam ring relative to the rotor.

[0105] According to the invention, it can be provided that the adjusting device enables an adjustment of the eccentricity of the cam ring relative to the rotor between the positive eccentricity and a negative eccentricity, wherein to set a negative eccentricity the cam ring is displaced from the zero eccentricity in a negative direction opposite the positive direction. In one embodiment of the method according to the invention, it can be provided that the vane pump is set up and designed so that a negative eccentricity of the cam ring relative to the rotor can also be set. To set a negative eccentricity of the cam ring, the cam ring is displaced, starting from the zero eccentricity, in a negative direction opposite the positive direction.

[0106] The ability to set a negative eccentricity allows the cam ring to be adjusted relative to the rotor to a negative eccentricity, as an alternative to zero eccentricity, when the rotor's direction of rotation changes or rotates in a second direction. This allows for the setting of an additional operating mode.

[0107] By adjusting the eccentricity from positive to negative eccentricity (or vice versa), the delivery direction of the vane pump can be maintained during a change in the direction of rotation of the rotor.

[0108] The vane pump according to the invention or the method according to the invention enables a variable adjustment of the stroke of the vane pump, if necessary up to a negative stroke direction or a negative eccentricity during operation of the vane pump or at standstill.

[0109] It is advantageous if, within the scope of the method according to the invention, it is provided that the adjusting device for adjusting the eccentricity of the cam ring relative to the rotor has at least one active actuator which acts directly or indirectly on the cam ring and which is controlled independently of the pressure of the pressure medium.

[0110] According to the invention, it can further be provided that the actuating device has two active actuators which are suitable for applying opposing forces to the cam ring, or the actuating device has an active actuator and a passive, non-controllable actuator, preferably a spring, which are suitable for applying opposing forces to the cam ring.

[0111] According to the invention, within the scope of the method for operating the vane pump, it can further be provided that the actuating device has a first pressure chamber between an outer side of the cam ring and an inner wall of the pump housing, wherein the first pressure chamber is subjected to a compressive force in order to press the cam ring in a positive direction and / or that the actuating device has a second pressure chamber between an outer side of the cam ring and an inner wall of the pump housing, wherein the second pressure chamber is subjected to a compressive force in order to press the cam ring in a negative direction.

[0112] According to the invention, it can further be provided that the vane pump is designed as a power steering pump and / or as an emergency power steering pump and / or the consumer is a vehicle steering system of a vehicle. The present invention also relates to a computer program product with program code means for carrying out a method according to one of claims 17 to 24 or a method with the method features described above when the program is executed on a control device of a vane pump according to one of claims 1 to 16.

[0113] It is particularly advantageous if the computer program product is configured such that the control device controls the actuating device depending on the driving situations of a vehicle or takes these into account. Preferably, the vane pump according to the invention, in particular in an embodiment as a power steering pump and / or as an emergency power steering pump, is switched on when the vehicle engine is switched off. Furthermore, the setting of a zero eccentricity can be provided when the output shaft of the vehicle transmission, which drives the drive shaft or the rotor of the vane pump, is stationary or not rotating. The setting of a zero eccentricity or even a negative eccentricity can also be provided when the rotor rotates in the second direction of rotation or when the vehicle in which the vane pump is installed is reversing.

[0114] Preferably, within the scope of the invention, the vane pump according to the invention is switched off when the internal combustion engine is driving the main steering pump. It may be advantageous to provide for brief overlaps, particularly in the operating situation in which the internal combustion engine is switched off and the pressure medium supply to the consumer, in particular the steering gear, is then taken over by the power steering pump or emergency power steering pump (and vice versa).

[0115] Preferably, it is provided that, apart from brief overlaps when one of the pumps is switched off and the other pump is switched on, no simultaneous delivery is intended. In principle, however, it would also be conceivable for both pumps to deliver pressure medium simultaneously. Switching off the vane pump according to the invention, when used in addition to a main steering pump and the vane pump according to the invention is driven by an output shaft of a vehicle transmission, can be achieved independently of the speed of the output shaft or the speed of the rotor / drive shaft of the vane pump in that the adjusting device, controlled by the control device, sets a zero eccentricity of the cam ring relative to the rotor. As a result, the pressure medium flow delivered by the vane pump according to the invention can be quickly switched on and off as required.The vane pump according to the invention can thus be switched on or off depending on whether the vehicle engine is switched on or off by adjusting the zero eccentricity or by displacing the cam ring relative to the rotor in such a way that the rotational axis of the rotor and the rotational axis of the cam ring are not arranged or run coaxially.

[0116] The solution according to the invention thus makes it possible to set a zero flow rate or zero eccentricity of the vane pump according to the invention not only when the output shaft is stationary or the rotor is not rotating, or when the rotor is rotating in the second direction of rotation, but also in a variety of operating states. The pump's energy consumption can thus be reduced to a minimum. The control device and at least one active actuator are particularly suitable for this purpose.

[0117] The solution according to the invention is not limited to setting a zero eccentricity only when the rotor is at a standstill and / or when the rotor rotates in a second direction of rotation.

[0118] The invention further relates to a system for generating a pressure medium flow for a consumer, comprising a vane pump according to one of claims 1 to 16 or a vane pump operated according to one of claims 17 to 24, for conveying a pressure medium for the at least one consumer.

[0119] The system is advantageous if the consumer is a vehicle's steering system. The system features a main steering pump driven by a vehicle engine to supply the vehicle's steering system with pressure fluid. The drive shaft of the vane pump is driven by an output shaft of a vehicle transmission.

[0120] Preferably, the vane pump is designed as a power steering pump and / or as an emergency power steering pump in order to supply the vehicle steering with pressure medium when the vehicle engine is switched off.

[0121] The system according to the invention makes it particularly advantageous to save energy while still ensuring the vehicle's steering capability. Particularly in the driving situations already described, it can advantageously be provided that the vehicle engine is switched off or is switched off, whereby the main steering pump is then no longer operated. However, its function can then be taken over by the power steering pump or the emergency power steering pump (in case the vehicle engine fails unintentionally), which is driven by the output shaft of the vehicle's transmission.

[0122] The system according to the invention is particularly suitable for ensuring that the vehicle steering system is still supplied with a pressure medium flow even in the event of a vehicle engine failure.

[0123] The present invention also relates to a steering system of a vehicle having a vehicle steering system and a main steering pump for generating a pressure medium flow for the vehicle steering system and additionally a system according to claim 27 or a vane pump according to one of claims 1 to 16 or a vane pump operated according to one of claims 17 to 24.

[0124] Features described in connection with one of the subject matters of the invention, namely the vane pump according to the invention, the computer program product, the system for generating a pressurized medium flow according to the invention, the method for operating a vane pump according to the invention, or the steering system according to the invention, can also be advantageously implemented for the other subject matters of the invention. Likewise, advantages mentioned in connection with one of the subject matters of the invention can also be understood to relate to the other subject matters of the invention.

[0125] It should also be noted that terms such as "comprising," "having," or "with" do not exclude other features or steps. Furthermore, terms such as "a" or "the," which indicate a singular number of steps or features, do not exclude a plurality of features or steps—and vice versa.

[0126] In a purist embodiment of the invention, however, it may also be provided that the features introduced in the invention with the terms "comprising," "having," or "with" are listed exhaustively. Accordingly, one or more lists of features may be considered complete within the scope of the invention, for example, for each claim. The invention may, for example, consist exclusively of the features mentioned in claim 1.

[0127] It should be noted that terms such as "first" or "second" etc. are used primarily for reasons of distinguishing between respective device or process features and are not necessarily intended to indicate that features are mutually dependent or related to one another.

[0128] In the following, embodiments of the invention are described in more detail with reference to the drawing.

[0129] It shows:

[0130] Figure 1 shows a schematic diagram of a vane pump according to the invention;

[0131] Figure 2 shows an active actuator of an actuating device in a first exemplary embodiment;

[0132] Figure 3 shows an active actuator of an actuating device in a second exemplary embodiment;

[0133] Figure 4 is a schematic diagram of an operating mode of the vane pump according to the invention;

[0134] Figure 5 is a schematic diagram of a further operating mode of the vane pump according to the invention at zero eccentricity;

[0135] Figure 6 is a schematic diagram of an embodiment of the adjusting device for adjusting the eccentricity of the cam ring; Figure 7 is a schematic diagram of another embodiment of the adjusting device for adjusting the eccentricity of the cam ring;

[0136] Figure 8 is a schematic diagram of a further embodiment of the adjusting device with a superposition device for adjusting the eccentricity of the cam ring;

[0137] Figure 9 is a schematic diagram of another embodiment of the adjusting device for adjusting the eccentricity of the cam ring with two active actuators;

[0138] Figure 10 is a schematic diagram of another embodiment of the adjusting device for adjusting the eccentricity of the cam ring;

[0139] Figure 1 1 is a block diagram of a steering system with a vane pump for delivering the fluid to a consumer; and

[0140] Figure 12 is a schematic diagram of a steering system of a vehicle with a main steering pump driven by a vehicle engine and a vane pump according to the invention driven by a vehicle transmission.

[0141] Adjustable, single-stroke vane pumps 1 for generating a pressure medium flow for a consumer 2 are well known from the prior art, for which reference is also made, for example, to DE 10 2005 040 702 A1 and DE 10 2005 043 253 B4.

[0142] Therefore, only the features essential to the invention are described in more detail below.

[0143] As can be seen from Figure 1, the vane pump 1 according to the invention has a pump housing 3. In a manner not shown in detail, an outer ring can be inserted into the pump housing 3.

[0144] An adjustable cam ring 4 is inserted into the pump housing 3.

[0145] The pump housing 3 offers sufficient space for the displacement of the cam ring 4 between a positive eccentricity and a zero eccentricity or, if necessary, also a negative eccentricity or between a positive stroke and a zero stroke or, if necessary, also a negative stroke, as will be shown in more detail below.

[0146] The cam ring 4 is adjustable or displaceable within a preferably elliptical space of the pump housing 3.

[0147] Within the cam ring 4, or in the cam ring 4, a rotor 5 is rotatably mounted via a drive shaft 6. Working chambers 8 defined by vanes 7 are formed between the rotor 5 and the cam ring 4. The vanes 7 are supported by the rotor 5 or are movably arranged in slots of the rotor 5, so that the vanes 7 can be advanced and retracted in the slots of the rotor 5. For this purpose, a rear vane fluid pressure is preferably used in a generally known manner.

[0148] The drive shaft 6 can also be referred to as the axis of rotation.

[0149] The drive shaft 6 or the rotation axis is fixed in position to the pump housing 3.

[0150] A suction port 9 and a pressure port 10 for a pressure medium are formed between the rotor 5 and the cam ring 4. In Figure 1, the suction port 9 is shown as the suction area, and the pressure port 10 is shown as the pressure area.

[0151] Figure 1 also shows lines 11 which lead to the consumer 2 or a pressure medium reservoir 12, for example a tank with the pressure medium.

[0152] In the exemplary embodiment, a line 11 leads from the pressure medium reservoir 12 to the suction connection 9. Accordingly, a line 11 leads from the pressure connection 10 to the consumer 2.

[0153] Figure 1 also shows a passive actuator 13, which is preferably a spring. Figure 1 also shows an active actuator 14. The passive actuator 13 and the active actuator 14 each act in opposite directions on the cam ring 4 to adjust its eccentricity relative to the rotor 5 or the drive shaft or rotation axis 6.

[0154] A possible adjustment of the eccentricity of the cam ring 4 relative to the rotor 5 is shown in Figure 1 as an example with the stroke 15. The stroke 15 can be positive or zero (zero eccentricity), depending on the position of the active actuator 14 according to Figure 1. The stroke 15 can also be negative if, in a special embodiment, the setting of a negative eccentricity is also provided.

[0155] Figure 1 also shows an example of a sealing point 16 which provides a seal between the pump housing 3 and the active actuator 14.

[0156] The adjustment of the active actuator 14 is symbolized in Figure 1 with a double arrow.

[0157] According to the invention, an adjusting device 17 is provided which is designed such that an adjustment of the eccentricity of the cam ring 4 is possible at least between a positive eccentricity and a zero eccentricity. With a positive eccentricity, the cam ring 4 is shifted from a zero eccentricity in a positive direction such that, upon rotation of the rotor 5 in a first rotational direction 18, the pressure medium flows into the working chambers 8 through the suction port 9 and flows out through the pressure port 10.

[0158] Zero eccentricity means that the central axes or the rotation axes of the cam ring 4 and the rotor 5 are arranged coaxially to each other.

[0159] In the illustration according to Figure 1, the cam ring 4 is shifted in a positive direction. The rotor 5 rotates in the first direction of rotation 18, so that pressure fluid flows into the suction port 9, which in this embodiment originates from the pressure fluid reservoir 12. The pressure fluid flows out again through the pressure port 10 or is conveyed to the consumer 2.

[0160] Depending on the direction of rotation of the drive shaft 6, the rotor 5 of the vane pump 1 rotates in the first direction of rotation 18 or an opposite second direction of rotation 19. The direction of rotation of the drive shaft 6 can, as shown in more detail below with reference to Figure 12, depend on the direction of rotation of an output shaft 105 connected to the drive shaft 6.

[0161] In the exemplary embodiment, a control device 20 is provided, which can control the actuating device 17, in particular the active actuator 14, based on various parameters such that a desired eccentricity of the cam ring 4 relative to the rotor 5 or even a zero eccentricity can be set. The control device 20 can also set a negative eccentricity if necessary, if the vane pump 1 according to the invention is provided or configured for this purpose.

[0162] In the exemplary embodiment, it is provided that when the rotor 5 is at a standstill and / or when the rotor 5 rotates in a second direction of rotation 19 which is opposite to the first direction of rotation 18, the adjusting device 17 sets the zero eccentricity of the cam ring 4 relative to the rotor 5.

[0163] Furthermore, a zero eccentricity of the cam ring 4 relative to the rotor 5 can be set as required when a pressure medium flow generated by the vane pump 1 is not required (standby operation).

[0164] The control device 20 is shown only in principle in Figure 1.

[0165] The adjusting device 17 for adjusting the eccentricity of the cam ring 4 relative to the rotor 5 has at least one active actuator 14 which acts on the cam ring 4 and which is controllable independently of the pressure of the pressure medium.

[0166] The at least one active actuator 14 can be fixedly connected to the cam ring 4 such that the actuator 14 can change the eccentricity of the cam ring 4 relative to the rotor 5 in a positive direction and a negative direction and can set both a positive eccentricity and a zero eccentricity and optionally a negative eccentricity.

[0167] Figure 6 shows an embodiment by way of example in which the adjusting device 17 has an active actuator 14 which is firmly or rigidly connected on one side to the cam ring 4 in order to adjust it by pulling and pushing or pushing.

[0168] A possible stroke 15 is symbolized in Figure 6 by the double arrow.

[0169] The actuating device 17 can also have two actuators, one actuator being connected to the cam ring 4 in such a way that the cam ring 4 is adjustable, in particular displaceable, in a positive direction to change the eccentricity, and one actuator being connected to the cam ring 4 in such a way that the cam ring 4 is adjustable, in particular displaceable, in a negative direction to change the eccentricity. For this purpose, the actuating device 17 can preferably have two active actuators 14 or one active actuator 14 and one passive actuator 13.

[0170] An embodiment of the actuating device 17 with two active actuators 14 is shown in Figure 9. The two active actuators 14 are designed and arranged to apply opposing forces to the cam ring 4. The active actuators 14 can be fixedly or loosely connected to the cam ring 4.

[0171] Figure 10 shows an embodiment in which the actuating device 17 has an active actuator 14 and a passive, non-controllable actuator 13, preferably a spring, which are also arranged and suitable for applying opposing forces to the cam ring 4.

[0172] The control device 20 can control the actuating device 17 or the active actuators 14 accordingly in order to make a desired setting.

[0173] In the exemplary embodiment, the adjusting device 17 can be configured to adjust the position of a stop 21 against which the cam ring 4 strikes when it has reached one of its end positions, e.g., the maximum positive eccentricity or the zero eccentricity. This is illustrated by way of example in Figure 7. As also illustrated in Figure 7, the adjusting device 17 can optionally additionally comprise a passive actuator 13, preferably a spring, which acts directly on the cam ring 4 such that the cam ring 4 is subjected to a compressive force in the direction of the stop 21.

[0174] To change the eccentricity of the cam ring 4 relative to the rotor 5, the adjusting device 17 can have a first pressure chamber 22 between an outer side of the cam ring 4 and an inner wall of the pump housing 3. A pressure in the first pressure chamber 22 can apply a compressive force to the cam ring 4 in order to press the cam ring 4 in a positive direction. Alternatively, or preferably additionally, the adjusting device 17 can further have a second pressure chamber 23 between an outer side of the cam ring 4 and an inner wall of the pump housing 3. The pressure in the second pressure chamber 23 can act in such a way that the cam ring 4 is subjected to a compressive force in order to press the cam ring 4 in a negative direction.

[0175] The pressure chambers 22, 23 can be regulated in a generally known manner by the pressure medium or the pressure of the pressure medium that is to be conveyed from the pressure medium reservoir 12 to a consumer 2. For this purpose, a flow control valve (not shown in detail) can be provided in a known manner.

[0176] Within the scope of the exemplary embodiment, the use of a flow control valve may be provided. However, within the scope of the exemplary embodiment, it may also be provided that no flow control valve is used, or that the vane pump 1 does not have a flow control valve, or that no flow control valve is provided for the method according to the invention.

[0177] It should be noted that the design of the vane pump 1 with a first pressure chamber 22 and a second pressure chamber 23 is optional for all exemplary embodiments. A first pressure chamber 22 and a second pressure chamber 23 can also be dispensed with within the scope of the invention, wherein the design of a first pressure chamber 22 and a second pressure chamber 23 can be suitable, in particular for adjusting the cam ring 4 within a positive eccentricity or, if appropriate, within a negative eccentricity, in order to vary the geometric working volume at the positive eccentricity or the negative eccentricity, in particular depending on the rotational speed of the rotor 5. Figure 1 shows the first pressure chamber 22 and the second pressure chamber 23 only as examples, and seals and hydraulic connections have been omitted. Their arrangement and design are known from the prior art.It should be noted that in the embodiment shown in Figure 1, the pressure chambers 22, 23 are also optional. The design or presence of pressure chambers 22, 23 depends on whether a speed-dependent control is provided in addition to the control using the actuating device 17 or whether the pressure chambers 22, 23 are to be used within the scope of the actuating device 17.

[0178] Figure 8 shows a design with pressure chambers 22, 23. In the exemplary embodiment according to Figure 8, the actuating device 17 is provided with a superimposing device 24 in order to superimpose the pressure in the first pressure chamber 22 and / or the second pressure chamber 23. The pressure chambers 22, 23 can thus be used to adjust the eccentricity of the cam ring 4 between a positive eccentricity and a zero eccentricity or even a negative eccentricity. In the exemplary embodiment according to Figure 8, the superimposing device 24 has an active actuating element 14 and a passive actuating element 13, for example a spring, in order to use them to superimpose the pressure in the pressure chambers 22, 23. The superimposing device 24 can also have only one active actuating element 14 or two active actuating elements 14.In all embodiments, it can preferably be provided that the at least one active actuator 14 is a mechanical and / or electrical and / or electromechanical and / or hydraulic and / or pneumatic actuator that can be controlled independently of the pressure of the pressure medium or can be controlled accordingly.

[0179] Figure 2 shows an example of an active actuator 14 in an electromechanical design or with an electromechanical control.

[0180] Figure 3 shows an example of an active actuator 14 in an embodiment as a pneumatic or hydraulic actuator or with a pneumatic or hydraulic control.

[0181] The exemplary embodiment also serves to disclose a method for operating an adjustable, single-stroke vane pump 1 for generating a pressure medium flow for a consumer 2.

[0182] The pressure medium is preferably a hydraulic fluid, in particular a pressure oil.

[0183] With regard to the method for operating an adjustable, single-stroke vane pump 1 as well as with regard to the computer program product, reference is also made to the above and the following explanations.

[0184] Figure 4 shows an operating mode or a configuration of the vane pump 1 which makes it possible to shift the cam ring 4 relative to the rotor 5 into a negative eccentricity. Such a shift can be provided when the direction of rotation of the rotor 5 changes. By shifting it into a negative eccentricity, it can be achieved that, despite a changed direction of rotation of the rotor 5, the delivery direction of the vane pump 1 does not change, i.e., that pressure medium continues to flow into the working chambers 8 via the suction port 9 and flows out through the pressure port 10. As already explained above, such a configuration or such an operating mode is optional. As a rule, it is provided that, when the rotor 5 rotates in the second direction of rotation 19, a zero eccentricity is set, i.e., that no delivery takes place.Alternatively, however, it is also possible, if the vane pump 1 is designed accordingly, to set a negative eccentricity so that pressure medium continues to be pumped.

[0185] The middle image in Figure 4 shows the rotor 5 rotating in the first direction 18. When the direction of rotation changes, i.e., when the rotor 5 rotates in the second direction 19 (right image), the cam ring 4 assumes a position with negative eccentricity. The delivery direction of the vane pump is thus maintained, meaning the suction and delivery (see the arrows in Figure 4) remain unchanged.

[0186] Figure 5 shows an operating mode of the vane pump 1 in which no pumping takes place.

[0187] The cam ring 4 is set to zero eccentricity. In this state, the vane pump 1 can be operated without any pressure fluid being pumped, regardless of the direction of rotation 18, 19 of the rotor 5 of the vane pump 1.

[0188] A zero eccentricity, as shown in Figure 5, is controlled by the control device 20 and set by the actuating device 17, preferably when the rotor 5 is stationary and / or when the rotor 5 rotates in a second direction of rotation 19. However, a zero eccentricity can also be set when the rotor 5 rotates in the first direction of rotation 18, or a zero eccentricity can be set independently of the direction of rotation and / or the speed of the rotor 5, in particular if it is desired that the vane pump 1 according to the invention does not deliver any pressure medium and thus saves energy accordingly.

[0189] Figure 11 shows a first embodiment of a steering system 100 for a motor vehicle, in particular for a passenger car or a commercial vehicle. The steering system 100 may comprise, in a manner not shown in detail, a steering wheel to be operated by the driver, which, via a steering column, acts on a vehicle wheel via a steering gear and adjusts the wheel according to the driver's command. The steering system 100 comprises the vane pump 1 according to the invention, which generates a pressure medium flow or hydraulic pressure for a consumer 2.

[0190] The consumer 2 can be an actuating cylinder, which typically has two separate chambers, each connected to a pressure control valve via hydraulic lines. The hydraulic pressure or pressure medium flow generated by the vane pump 1 can be fed to the pressure control valve.

[0191] Figure 12 shows a particularly advantageous system 200 for generating a pressure medium flow for a consumer 2, comprising a vane cell pump 1 according to the invention or a vane cell pump 1 which is operated according to the method according to the invention, for conveying a pressure medium for the at least one consumer 2. In Figure 12, the consumer is a vehicle steering system 101 of a vehicle. The system 200 has a main steering pump 102 for supplying the vehicle steering system 101 with pressure medium. The main steering pump 102 is driven by a vehicle engine 103. The vehicle engine 103 is preferably an internal combustion engine. The vehicle can preferably be a vehicle in which an internal combustion engine is used for propulsion, or also a vehicle which has both an internal combustion engine and an electric motor, in particular a so-called hybrid vehicle.In the exemplary embodiment according to Figure 12, the drive shaft 6 of the vane pump 1, which is part of the system 200, is driven by an output shaft 105, which in turn is driven by a vehicle transmission 104 or is part of the vehicle transmission 104. The vehicle transmission 104 is driven or accelerated by the vehicle engine 103. When the vehicle is rolling (or coasting) and the combustion engine is off, the vehicle transmission 104 continues to be driven or rotates by the vehicle wheels. The vehicle engine 103 and the vehicle transmission 104 are not part of the system 200.

[0192] In the embodiment according to Figure 12, the vane pump 1 is designed as a power steering pump and / or as an emergency power steering pump in order to supply the vehicle steering system 101 with pressure medium when the vehicle engine 103 is switched off or not running or when the vehicle engine has failed.

[0193] In the exemplary embodiment according to Figure 12, it can preferably be provided that the control device 20 sets a zero eccentricity when the output shaft 105 or the rotor 5 is stationary and / or that a zero eccentricity of the cam ring 4 is set relative to the rotor 5 when the rotor 5 rotates in the second direction of rotation 19, which is particularly the case when the vehicle is reversing. Alternatively, when the vehicle is reversing, i.e. when the rotor 5 rotates in the second direction of rotation 19, a negative eccentricity can also be set, so that a delivery, preferably a delivery of pressure medium or hydraulic fluid, continues to take place from the pressure medium reservoir (tank) to the consumer 2, in particular a vehicle steering system 101 or an actuating cylinder / steering cylinder of the vehicle steering system 101.

[0194] In the embodiment according to Figure 12, it is preferably provided that the zero eccentricity is set when the rotor 5 rotates in the first direction of rotation 18, but the vehicle steering 101 does not require a pressure medium flow from the vane pump 1 according to the invention, for example because a supply by the main steering pump 102 is sufficient and / or because the vehicle steering 101 does not require a pressure medium.

[0195] In the embodiment according to Figure 12, it is preferably provided that the main steering pump 102 and the vane pump 1 according to the invention are not operated simultaneously, but a short-term overlap can be provided when one of the pumps 1, 102 is switched off, so that a continuous supply to the vehicle steering system 101 is ensured.

[0196] The exemplary embodiment according to Figure 12 also serves to disclose a steering system 100 in a second embodiment. The steering system 100 comprises a vehicle steering system 101, a main steering pump 102 for generating a pressure fluid flow for the vehicle steering system 101, and additionally a vane pump 1 according to the invention and / or the system 200.

[0197] An advantageous motor vehicle may comprise the steering system 100, in particular according to Figure 12, and additionally a vehicle engine 103 and a vehicle transmission 104, wherein the vehicle engine 103 drives the main steering pump 102 and the vehicle transmission 104 or an output shaft 105 of the vehicle transmission 104 drives the drive shaft 6 or the rotor 5 of the vane pump 1 according to the invention. List of reference symbols:

[0198] 1 vane pump

[0199] 2 consumers

[0200] 3 pump housing

[0201] 4 Curve ring

[0202] 5 Rotor

[0203] 6 Drive shaft

[0204] 7 wings

[0205] 8 Working chamber

[0206] 9 Suction connection

[0207] 10 Pressure connection

[0208] 11 Line

[0209] 12 Pressure medium reservoir

[0210] 13 passive actuator

[0211] 14 active actuator

[0212] 15 strokes

[0213] 16 Sealing point

[0214] 17 Adjusting device

[0215] 18 first direction of rotation

[0216] 19 second direction of rotation

[0217] 20 Control device

[0218] 21 stop

[0219] 22 first pressure chamber

[0220] 23 second pressure chamber

[0221] 24 Overlay device

[0222] 100 Steering system

[0223] 101 Vehicle steering

[0224] 102 Main steering pump

[0225] 103 Vehicle engine

[0226] 104 vehicle transmissions

[0227] 105 Output shaft

[0228] 200 System for generating a pressure medium flow

Claims

P a t e n t a n s p r ü c h e 1. Adjustable, single-stroke vane pump (1) for generating a pressure medium flow for a consumer (2), comprising a pump housing (3) in which an adjustable cam ring (4) is inserted, a rotor (5) and a drive shaft (6) which are rotatable within the cam ring (4), wherein the rotor (5) carries vanes (7) which form working chambers (8) between the rotor (5) and the cam ring (4), and wherein a suction connection (9) and a pressure connection (10) for a pressure medium are formed between the rotor (5) and the cam ring (4), and comprising an adjusting device (17) for changing the eccentricity of the cam ring (4) relative to the rotor (5), characterized in that the drive shaft (6) is designed and configured for drive by an output shaft (105) of a vehicle transmission (104), and the adjusting device (17) is designed such thatthat an adjustment of the eccentricity of the cam ring (4) is possible at least between a positive eccentricity and a zero eccentricity, wherein at the positive eccentricity the cam ring (4) is shifted from the zero eccentricity in a positive direction such that upon rotation of the rotor (5) in a first direction of rotation (18), the pressure medium flows into the working chambers (8) through the suction connection (9) and flows out through the pressure connection (10), and wherein at the zero eccentricity during rotation of the rotor (5) no pressure medium is conveyed to the consumer (2).

2. Vane pump according to claim 1, characterized in that a control device (20) is provided and arranged which controls the adjusting device (17) in such a way that the zero eccentricity of the cam ring (4) relative to the rotor (5) can be adjusted independently of the direction of rotation and a speed of the rotor (5).

3. Vane pump according to claim 2, characterized in that the control device (20) controls the adjusting device (17) in such a way that when a vehicle is at a standstill and / or when a pressure medium flow generated by the vane pump (1) is not required, and / or when a vehicle in which the vane pump (1) is installed is reversing, the adjusting device (17) sets the zero eccentricity of the cam ring (4) relative to the rotor (5).

4. Vane pump according to claim 1, 2 or 3, characterized in that the adjusting device (17) is designed such that an active adjustment of the eccentricity of the cam ring (4) relative to the rotor (5) is possible independently of and / or in addition to a volume flow-dependent control.

5. Vane pump according to one of claims 1 to 4, characterized in that the adjusting device (17) for adjusting the eccentricity of the cam ring (4) relative to the rotor (5) has at least one active actuator (14) which acts directly or indirectly on the cam ring (4) and which is controllable independently of the pressure of the pressure medium.

6. Vane pump according to claim 5, characterized in that the adjusting device (17) for adjusting the eccentricity of the cam ring (4) relative to the rotor (5) has at least one active actuator (14) and additionally a flow control valve which influences the eccentricity of the cam ring (4) as a function of a volume of the pressure medium flow from the pressure connection (10) to the consumer (2).

7. Vane pump according to claim 5, characterized in that the adjusting device (17) for adjusting the eccentricity of the cam ring (4) relative to the rotor (5) has at least one active actuator (14) and no flow control valve which influences the eccentricity of the cam ring (4) as a function of a volume of the pressure medium flow from the pressure connection (10) to the consumer (2).

8. Vane pump according to claim 5, 6 or 7, characterized in that the at least one active actuator (14) is fixedly connected to the cam ring (4) such that the active actuator (14) can change the eccentricity of the cam ring (4) relative to the rotor (5).

9. Vane pump according to one of claims 1 to 8, characterized in that the adjusting device (17) has two adjusting elements (13, 14), wherein one adjusting element (13, 14) is connected to the cam ring (4) in such a way that the cam ring (4) can be displaced in a positive direction to change the eccentricity relative to the rotor (5) and one adjusting element (13, 14) is connected to the cam ring (4) in such a way that the cam ring (4) can be displaced in a negative direction to change the eccentricity.

10. Vane pump according to claim 9, characterized in that the adjusting device (17) has two active actuators (14) which are suitable for applying opposing forces to the cam ring (4), or the adjusting device (17) has an active actuator (14) and a passive, non-controllable actuator (13), preferably a spring, which are suitable for applying opposing forces to the cam ring (4).

11. Vane pump according to one of claims 5 to 8, characterized in that the at least one active actuator (14) is a mechanical and / or electrical and / or electromechanical and / or hydraulic and / or pneumatic actuator that can be controlled independently of the pressure of the pressure medium.

12. Vane pump according to one of claims 1 to 11, characterized in that the adjusting device (17) is designed to adjust the position of a stop (21) against which the cam ring (4) strikes when it has reached one of its two end positions, wherein the adjusting device (17) additionally has a passive actuator (13), preferably a spring, which acts on the cam ring (4) in such a way that the cam ring (4) is loaded with a compressive force in the direction of the stop (21).

13. Vane pump according to one of claims 1 to 12, characterized in that the adjusting device (17) for changing the eccentricity of the cam ring (4) relative to the rotor (5) has a first pressure chamber (22) between an outer side of the cam ring (4) and an inner wall of the pump housing (3), wherein a pressure in the first pressure chamber (22) applies a compressive force to the cam ring (4) in order to press the cam ring (4) in a positive direction and / or that the adjusting device (17) has a second pressure chamber (23) between an outer side of the cam ring (4) and an inner wall of the pump housing (3), wherein a pressure in the second pressure chamber (23) applies a compressive force to the cam ring (4) in order to press the cam ring (4) in a negative direction.

14. Vane pump according to claim 13, characterized in that the adjusting device (17) has a superimposing device (24) in order to superimpose the pressure in the first pressure chamber (22) and / or the second pressure chamber (23).

15. Vane pump according to one of claims 1 to 14, characterized in that the vane pump (1) is designed as a power steering pump and / or as an emergency power steering pump and / or the consumer (2) is a vehicle steering system (101) of a vehicle.

16. Vane pump according to one of claims 1 to 15, characterized in that the adjusting device (17) is designed such that an adjustment of the eccentricity of the cam ring (4) relative to the rotor (5) between the positive eccentricity and a negative Eccentricity is possible, whereby in the case of negative eccentricity the cam ring (4) is shifted from the zero eccentricity into a negative direction opposite to the positive direction.

17. A method for operating an adjustable, single-stroke vane pump (1) for generating a pressure medium flow for a consumer (2), with a pump housing (3) in which an adjustable cam ring (4) is inserted, with a rotor (5) and a drive shaft (6) which are rotatable within the cam ring (4), wherein the rotor (5) carries vanes (7) which form working chambers (8) between the rotor (5) and the cam ring (4), and wherein a suction connection (9) and a pressure connection (10) for a pressure medium are formed between the rotor (5) and the cam ring (4), and with an adjusting device (17) for changing the eccentricity of the cam ring (4) relative to the rotor (5), characterized in thatthat the drive shaft (6) is driven by an output shaft (105) of a vehicle transmission (104) and the adjusting device (17) enables an adjustment of the eccentricity of the cam ring (4) at least between a positive eccentricity and a zero eccentricity, wherein to adjust the positive eccentricity the cam ring (4) is displaced from the zero eccentricity in a positive direction, wherein with a positive eccentricity and a rotation of the rotor (5) in a first direction of rotation (18) pressure medium flows into the working chamber (8) through the suction connection (9) and flows out through the pressure connection (10), and wherein when the eccentricity of the cam ring (4) is adjusted to a zero eccentricity no pressure medium is delivered to the consumer (2).

18. Method according to claim 17, characterized in that the adjusting device (17) sets the zero eccentricity of the cam ring (4) relative to the rotor (5) independently of the direction of rotation and a speed of the rotor (5).

19. Method according to claim 18, characterized in that the adjusting device (17) is controlled in such a way that, when a vehicle is at a standstill and / or when traveling forwards, when a pressure medium flow generated by the vane cell pump (1) is not required, and / or when a vehicle in which the vane cell pump is installed is traveling backwards, the adjusting device (17) sets the zero eccentricity of the cam ring (4) relative to the rotor (5).

20. Method according to one of claims 17 to 19, characterized in that the adjusting device (17) for adjusting the eccentricity of the cam ring (4) relative to the rotor (5) has at least one active actuator (14) which acts directly or indirectly on the cam ring (4) and which is controlled independently of the pressure of the pressure medium and / or the speed of the drive shaft (6).

21. Method according to claim 20, characterized in that the actuating device (17) has two active actuators (14) which are suitable for applying opposing forces to the cam ring (4), or the actuating device (17) has an active actuator (14) and a passive, non-controllable actuator (14), preferably a spring, which are suitable for applying opposing forces to the cam ring (4).

22. Method according to one of claims 17 to 21, characterized in that the adjusting device (17) has a first pressure chamber (22) between an outer side of the cam ring (4) and an inner wall of the pump housing (3), wherein the first pressure chamber (22) is subjected to a compressive force in order to press the cam ring (4) in a positive direction and / or that the adjusting device (17) has a second pressure chamber (23) between an outer side of the cam ring (4) and an inner wall of the pump housing (3), wherein the second pressure chamber (23) is subjected to a compressive force in order to press the cam ring (4) in a negative direction.

23. Method according to one of claims 17 to 22, characterized in that the vane pump (1) is designed as a power steering pump and / or as an emergency power steering pump and / or the consumer (2) is a vehicle steering system (101) of a vehicle.

24. Method according to one of claims 17 to 23, characterized in that the adjusting device (17) adjusts the eccentricity of the cam ring (4) relative to the rotor (5) between the positive eccentricity and a negative eccentricity, whereby to set a negative eccentricity the cam ring (4) is displaced from the zero eccentricity into a negative direction opposite to the positive direction.

25. Computer program product with program code means for carrying out a method according to one of claims 17 to 24 when the program is executed on a control device (20) of a vane pump (1) according to one of claims 1 to 16.

26. System (200) for generating a pressure medium flow for a consumer (2) comprising a vane pump (1) according to one of claims 1 to 16 or a vane pump (1) operated according to one of claims 17 to 24, for conveying a pressure medium for the at least one consumer (2).

27. System (200) according to claim 26, characterized in that the consumer (2) is a vehicle steering system (101) of a vehicle, and wherein a main steering pump (102) driven by a vehicle engine (103) is provided for supplying the vehicle steering system (101) is provided with pressure medium, and wherein the drive shaft (6) of the vane pump (1) is driven by an output shaft (105) of a vehicle transmission (104).

28. System (200) according to claim 27, characterized in that the vane pump (1) is designed as a power steering pump and / or as an emergency power steering pump in order to supply the vehicle steering system (101) with pressure medium when the vehicle engine (103) is switched off.

29. Steering system (100) of a vehicle with a vehicle steering system (101) and a main steering pump (102) for generating a pressure medium flow for the vehicle steering (101) and additionally a system (200) according to claim 27 or a vane pump (1) according to one of claims 1 to 16 or a vane pump (1) operated according to one of claims 17 to 24.

Images