EP3179108B1 - Pump with adjustable transport volume - Google Patents

Description

The invention relates to a pump with adjustable delivery volume, which includes an adjustment and associated valves for adjusting the delivery volume. In particular, the invention relates to a pump comprising an adjusting device for adjusting the specific delivery volume of the pump. The valves are fluidically connected to the adjusting device in order to be able to adjust the delivery volume of the pump by acting on the adjusting device with pressurized actuating fluid. The pump can serve to supply an assembly, in particular an aggregate of a vehicle, such as a motor vehicle, with lubricating oil, working fluid or cooling fluid. The pump is expediently a positive displacement pump. In preferred applications, the pump serves as a lubricating oil pump for supplying a combustion engine of a vehicle with lubricating oil, so is an engine lubricating oil pump.

In engine lubricating oil pumps, it is a common design that an adjusting element serving to influence the delivery volume, such as a pivotable adjusting ring, is charged with the oil delivered by the pump, ie the oil from the high pressure side of the oil circuit supplied by the pump. In this way, the delivery volume flow is limited when reaching a certain pressure threshold. Depending on the engine boundary conditions, such as engine speed, engine temperature, necessity of piston cooling and the like, often an adjustment of the delivery volume, preferably the specific delivery volume, in the form of two or possibly more pressure stages is used. Alternatively or additionally, a control of the pump in dependence on an engine map, ie a map control, be realized. The pressurization of the adjusting can be done in simple cases directly via a controlled by the engine control multi-way valve. If the electromagnetically operable multi-way valve can not be arranged in or on a housing of the pump and / or sufficient dimensioning of the flow cross sections in the valve or on the way to or from the valve for structural reasons can not be implemented for rapid adjustment, a hydraulic valve can be provided , which controls the pressurization or depressurization of the usually movable against the force of a spring adjusting. At least in such embodiments, a pressure which acts on a partial surface of a pilot piston, which is typically designed as a stepped piston, of the hydraulic valve is modulated by way of the electromagnetically controllable multiway valve.

From the WO 2006/066405 A1 a pump is known, which has a variable adjustment of the delivery volume adjustable forth and forth, which is acted upon in two adjusting chambers, each with a setting pressure in a direction of adjustment. A spring device counteracts the setting pressures in a return direction to the adjusting member. In the first control chamber, the adjusting member is acted upon directly by a branched off from the high pressure side of the pump actuating fluid. The pressure prevailing in the second control chamber actuating pressure is adjustable by means of a solenoid valve. With regard to the first adjusting chamber, it is also mentioned that in modified embodiments, alternatively, its setting pressure can also be adjusted by means of a solenoid valve.

From the WO 2008/037070 A1 is a pump with a variable adjustment of the delivery volume adjustment known, which is acted upon in a first actuating chamber with a first control pressure and in a second control chamber with a second control pressure in each case in a direction of adjustment. The set pressures counteract a spring device in the return direction. Both actuating chambers are each preceded by a fluidically actuable valve in order to be able to change the control pressure of the respective control chamber. The fluidically actuated valves are each supplied from the high pressure side of the pump branched actuating fluid. The actuating fluid can be supplied via the valves of the respective associated adjusting chamber or discharged into a reservoir. One of the two valves is actuated directly with a control fluid diverted from the high pressure side of the pump. The other of the two valves is fluidly actuated by means of a solenoid valve.

The US 2015/252803 A1 relates to a further adjustable feed pump with an adjusting ring, which is biased by means of a spring device in a first end position. At the adjusting ring three pressure chambers are formed, one of which is permanently acted upon by the fluid of the pressure side of the pump and acts against the force of the spring means. The second and the third pressure chamber can be acted upon by a fluid respectively solenoid valve with pressurized fluid and act in the direction of the spring means. The US 2013/195 705 A1 relates to an adjustable vane pump, which in one embodiment comprises two adjusting chambers, both acting against the force of a return element. One of the control chambers is connected directly to a high pressure side of the pump or an oil gallery, the second control chamber is supplied via a solenoid valve with actuating fluid.

It is an object of the invention to provide a pump which is adjustable in delivery volume, which simplifies valves which are used with respect to the adjustment, but is nevertheless flexibly adaptable in the delivery volume to the demand of an aggregate to be supplied.

The invention is based on a pump with adjustable delivery volume, comprising a pump housing with a delivery chamber, a rotatable in the delivery chamber conveyor rotor, an adjustment for adjusting the delivery volume of the pump, a pump housing arranged in the return device for generating a return in the direction of the adjustment acting restoring force, a fluidically actuated valve for controlled actuation of the adjusting device with a control fluid and a solenoid valve also includes for acting on the adjusting device with a control fluid. The delivery chamber has a delivery chamber inlet on a low-pressure side and a delivery chamber outlet on a high-pressure side for fluid to be delivered by means of the delivery rotor.

When the pump is disposed in a pump circuit, the low pressure side of the pump extends from a reservoir from which the pump sucks the fluid, through an inlet of the pump housing to at least the delivery chamber inlet. If the transition from low pressure to high pressure takes place in the delivery chamber, the low-pressure side of the pump also includes the low-pressure side of the delivery chamber, thus extending on the low-pressure side into the delivery chamber. The high pressure side of the pump includes the high pressure area extended within the pump housing and further extends beyond an outlet of the pump housing to at least the unit to be supplied with the fluid or, if the pump supplies multiple units with the fluid, to each of these units. In contrast to the terms "low-pressure side of the pump" and "high-pressure side of the pump", the term "suction region" is intended to designate a flow region extending on the low-pressure side of the pump only within the pump housing. On the other hand, the term "suction area" is not to be interpreted so that the pump according to the invention must suck the fluid from the reservoir against gravity. The pump can also be arranged in its delivery circuit at a location which is lower than the reservoir, so that the pump sucks the fluid with the aid of gravity. The pump can also be pre-charged, d. H. The pump may be preceded by a pre-charge pump.

The adjusting device comprises an adjusting member, which is movable for adjusting the delivery volume of the pump in the pump housing in a setting direction and a return direction and further comprises a first actuating chamber for generating a first control pressure for adjusting the adjusting and a further, second actuating chamber for generating a second actuating pressure for adjusting the adjusting member. The first actuating pressure is generated by a first actuating fluid located in the first actuating chamber and the second actuating pressure is generated by a second actuating fluid located in the second actuating chamber, wherein the first actuating pressure and the second actuating pressure act in the direction of adjustment to the adjusting member or each act. Preferably, the first actuating fluid and the second actuating fluid are diverted from the high pressure side of the pump.

In first embodiments, the first control pressure in the first control chamber and the second control pressure in the second control chamber each act directly on the adjusting member, which accordingly limits both the first control chamber and the second control chamber. In second embodiments, both the first control pressure in the first control chamber and the second control pressure in the second control chamber via a respective actuating piston and, accordingly, each act indirectly on the adjusting member.

The fluid-operated valve serves to adjust the control pressure of the first control chamber, and the solenoid valve is used to adjust the control pressure of the second control chamber. The fluidically operable valve has a control piston which is adjustable by means of a pressurized control fluid. In preferred embodiments, this valve is only fluidic actuated. The pressure of the control fluid counteracts the clamping force of a clamping device of the valve. The fluidically operable valve is referred to below as "fluidic valve". It may in particular be a hydraulic valve. The electromagnetic valve has a pressure port for a control fluid branched from the high-pressure side fluid of the pump, a working port for the actuating fluid, and a discharge port for the actuating fluid. The solenoid valve is electromagnetically actuated, preferably it is only electromagnetically actuated. The electromagnetic force counteracts the clamping force of a clamping device of the solenoid valve.

According to the invention, the working port of the solenoid valve for adjusting the control pressure of the second actuating chamber is connected to the second actuating chamber. Due to the inventive combination of a fluidic valve for adjusting the first control pressure and a solenoid valve, which is fluidly connected via its working port to the second actuating chamber, a pump is obtained, which is simplified with respect to the adjustment by means of the valves over the prior art, the Delivery volume but still the need of a supplied unit or system of multiple units can be flexibly adjusted. By the hydraulic valve, a maximum pressure level is set, when it reaches the delivery volume of the pump is stopped. Since fluidic valves are particularly robust and reliable, and also independent of electrical energy and / or control signals, a simple, inexpensive and reliable shutdown is guaranteed when the maximum pressure level is reached. By means of the solenoid valve, the maximum pressure level at which the delivery volume of the pump is stopped, depending on the type of Solenoid valve in one or more stages or continuously, basically arbitrarily, be adjusted to the maximum predetermined by the fluidic valve.

The fluidic valve comprises the already mentioned control piston, which is movable in a valve chamber of the fluidic valve between a first piston position and a second piston position and a clamping device for generating a force acting on the control piston in the direction of one of the piston positions clamping force. The clamping device may have one or more springs for generating the clamping force. The tensioning device can be formed, in particular, by a helical spring, which is arranged in the valve space and subjected to pressure. Furthermore, the fluidic valve comprises a pressure connection for a control fluid branched off from the high-pressure side fluid, a working connection for the actuating fluid connected to the first control chamber and a discharge connection for the actuating fluid.

The clamping device of the fluid-actuated valve is preferably provided for setting a piston position, in which the first actuating chamber is connected to the discharge port of the fluid-actuated valve. The control force counteracting the tensioning device is preferably provided for setting a piston position, in which the pressure connection of the fluidically actuatable valve is connected to the first setting chamber. In order to generate the control force, the fluidically actuatable valve has an inlet for control fluid branched off at the high-pressure side of the pump. The inlet of the fluidically operable valve is permanently connected to the high-pressure side of the pump, whereby permanently acting through the control fluid control force acts against the clamping device of the fluidic valve.

Advantageously, the pressure connection of the fluidic valve is connected to the working port of the fluidic valve and thus to the first actuating chamber, when the control force reaches a value by which the control piston of the fluidic valve is moved against the clamping device in the piston position, in which Pressure port of the fluidic valve is connected to the working port of the fluidic valve operable.

The clamping device of the fluid-actuated valve exerts a clamping force on the control piston of the fluid-actuated valve, which is greater than a occurring at proper and / or active function of the solenoid valve or resulting, acting against the clamping device of the fluid-operated valve control force. The clamping force counteracts the fluidic adjustment of the piston position, in which the pressure connection of the fluid-actuated valve is connected to the working port of the fluid-actuated valve. The clamping force of the clamping device of the fluidic actuated valve is designed so that the piston position, in which the pressure port of the fluidic valve is connected to the working port of the fluidic valve, is set only when a predetermined pressure level is reached, which is higher than a maximum pressure level to which the active and / or properly functioning solenoid valve regulates.

When the solenoid valve is functioning correctly and / or the solenoid valve is active, the pump is stopped by the solenoid valve to a maximum pump outlet pressure. By this maximum pump output pressure results against the clamping device of the fluidic valve acting control force which is smaller than the clamping force of the clamping device of the fluidic valve and thus preferably smaller than a necessary control force which is at least necessary to adjust the piston position, in which the pressure port of the fluidic valve is connected to the working port of the fluidic valve and thus to the first actuating chamber. If the solenoid valve fails due to a defect or if the activation of the solenoid valve is deactivated in selected operating states, the pump will not be regulated by the solenoid valve, whereby the pump output pressure may rise above the maximum pump output pressure. The fluidic valve limits this increase to a fail-safe pump outlet pressure. The fail-safe pump outlet pressure is greater than the maximum pump outlet pressure but less than a critical pump outlet pressure which could result in component damage.

Due to the fail-safe pump output pressure results against the clamping device of the fluidic valve acting control force which is greater than the clamping force of the clamping device of the fluidic valve and thus preferably greater than the necessary control force to adjust the piston position in which the pressure port of the fluidic valve with the Working connection of the fluidic valve is connected. This ensures safe operation, even if the solenoid valve fails or is not activated in certain operating states. It can thereby an accurate and flexible adaptability to the needs with a failure of the solenoid valve ensured security of supply can be realized. It can be realized a so-called second-level control or regulation for the delivery volume of the pump.

The control piston preferably has at least a first ring portion and a second ring portion, which are axially spaced from each other. The first ring section separates the pressure port and the working port from each other in one of the piston positions, thereby connecting the working port to the discharge port. In the other piston position, the first ring section separates the working port and the discharge port from each other, thereby connecting the pressure port to the working port. The second ring portion is disposed axially between the pressure port and the first ring portion. It is arranged axially between the pressure connection and the working connection. The second ring section has at least one axial passage opening, which fluidly connects the pressure connection and the first ring section to one another. In order to move the control piston fluidically against the tensioning device, the control piston has at least one control surface on which the control fluid acts, thereby resulting in the control force. The control surface is preferably formed by the first ring portion. The at least one passage opening of the second annular section fluidly connects the control surface and the inlet for the control fluid of the fluidic valve. In the piston position, in which the pressure connection and the working connection are connected to one another, the at least one through-opening fluidly connects the pressure connection and the working connection with one another. The term "axial" is particularly related to a longitudinal axis and / or displacement axis of the control piston of the fluidic valve, so that the term "axially" denotes a direction which extends on the longitudinal axis or displacement axis or parallel thereto.

Preferably, the control piston has at a first axial end a first axial projection for arranging the clamping device and at a second axial end a second axial projection for forming a stop. The tensioning device, in particular the helical spring, is preferably arranged or plugged on the first axial projection. The first axial projection preferably forms a spring seat. The tensioning device surrounds the first axial projection. The second axial projection forms a stop in the piston position in which the pressure port and the working port are separated from each other. The second axial projection is in the piston position, in which the pressure port and the working port are separated from each other are at a counter-attack. The axial projections have a diameter which is smaller than the diameter of the ring sections.

The first ring portion is formed as a solid body and thus not executed hollow. Preferably, the entire control piston is formed as a solid body. To ensure that the control piston is installed correctly, the ring sections differ in their diameter from each other. Preferably, the first ring portion has a diameter which is smaller than the diameter of the second ring portion. Furthermore, the fluidic valve has a housing which comprises at least two regions which are different from one another in their inner diameter. The housing of the fluidic valve has a stepped inner diameter. The ring sections are in each case with their diameter on the inner diameter of the housing and are preferably guided on the inner diameter. The housing of the fluidic valve is advantageously formed by the pump housing. In this case, the housing of the fluidic valve or a receptacle of the control piston of the fluidic valve is formed by a stepped bore.

The fluidic valve and / or the solenoid valve may or may each have one or more further valve connections, for example a further pressure connection and / or a further working connection and / or a further discharge connection. In simple and not least therefore preferred embodiments, the fluidic valve and / or the solenoid valve, however, only the three valve connections mentioned.

The spool and the valve ports of the fluidic valve and / or the solenoid valve may be arranged so that the working port is connected to the pressure port when the respective spool occupies the first piston position and the working port is disconnected from the pressure port and connected to the unload port when the spool valve respective control piston occupies the second piston position. The fluidic valve and / or the solenoid valve may further be arranged so that the control piston can assume a third piston position and the working port is separated from both the pressure port and the discharge port when the spool occupies the third piston position. In particular, the third piston position may be an intermediate position which the control piston can assume in the direction of movement between the first and the second piston positions. Basically, but also the first piston position or instead the second piston position of the optionally be three different piston positions the intermediate position. Embodiments are also possible in which the fluidic valve and / or the electromagnetic valve completely disconnects the working connection in each piston position from both the pressure connection and the discharge connection, but separates the working connection only from the pressure connection, but permits a comparatively low flow between the working connection and the discharge connection. or separates the working port from the discharge port while allowing a comparatively low flow between the working port and the pressure port. The fluidic valve and / or the solenoid valve is preferably a switching valve and switchable between said states. The respective valve can be designed in particular with only two switching states or exactly three switching states. Preferably, the switching states are defined by the piston positions.

The fluidic valve is preferably arranged in or on the pump housing. If it is arranged outside the suction region of the pump housing, the fluid can flow through the suction region with little resistance, since the flow in the suction region is not hindered by the fluidic valve. In preferred embodiments, the fluidic valve is arranged not only outside the suction area but outside the main flow through the pump housing. Therefore, in the preferred embodiments, the fluidic valve does not interfere with the outflow of fluid on the high pressure side of the pump housing.

If the pump is arranged in a fluid conveying circuit, the fluidic valve is arranged in preferred embodiments outside of the main flow of the delivery circuit in a bypass branch. The fluidic valve can thus be designed free of the requirement for a low-resistance main flow. The fluidic valve can be dimensioned correspondingly small and targeted to the fulfillment of its function, the control of the actuating fluid for the first control chamber, optimized. The main flow of the delivery circuit extends from the reservoir to the pump housing on the low-pressure side of the pump and includes the suction area of the pump housing. On the high pressure side, the main flow includes the high pressure area of the pump housing through which the fluid passes from the delivery chamber to an outlet of the pump housing and the subsequent high pressure area outside the pump housing to at least one unit to be supplied by the pump with the fluid. When the pump supplies several units, the flow becomes the aggregate as the main flow understood that has the highest volume requirement, measured as flow rate, or has to be supplied with the highest pressure.

The discharge port of the fluidic valve and / or the solenoid valve may be connected to the suction region of the pump, bypassing the reservoir. Control fluid flowing from the valve through the relief port may be returned to the pump's fluid delivery circuit in a relief passage downstream of the reservoir. The actuating fluid flowing out of the valve through the discharge port can be returned to the main flow at a connection point between the reservoir and the pump housing, such a connection point preferably being closer to the pump housing than to the reservoir. The discharge channel extends from the discharge port to the junction with the main stream. The fluidic valve and / or the solenoid valve is advantageously not in fluid communication with the reservoir via the discharge port. No fluid flows from the reservoir into the valve space of the fluidic valve and / or the electromagnetic valve via the discharge connection, and in particular no fluid flows from the fluidic valve and / or from the solenoid valve via the discharge connection to the reservoir.

In preferred embodiments, the actuating fluid is returned directly into the suction region of the pump housing. The discharge channel opens in such embodiments in the suction area, so it is connected directly to the suction area. The mouth in the suction area forms said connection point.

By the return of the controlled actuating fluid directly into the suction region of the pump housing or at least to a junction which is formed upstream of the pump port of the low pressure side, but downstream of the reservoir, an undesirable foaming is counteracted, which usually occurs when returned to the reservoir. The energy required to drive the pump is lowered because the returned control fluid is still at a higher pressure than the fluid in the reservoir. In particular, in embodiments in which the actuating fluid is recirculated directly into the suction region of the pump housing, a certain precharge takes place on the low pressure side of the pump. If the fluid is preferably a liquid, such as a lubricating oil or a hydraulic oil, cavitation can be counteracted. If the actuating fluid were discharged directly into the environment through the discharge connection, the actuating fluid flowing back to the reservoir would be additionally contaminated. Further there would be the danger that air is sucked into the fluidic valve and / or the electromagnetic valve via the discharge connection from the surroundings, which air reaches the working connection via leakages and from there into the main flow flowing through the pump housing. These two disadvantages are also eliminated by the invention. Another positive effect is the sealing off of the valve from the reservoir. If the pump is used as a lubricating oil pump or working oil pump, there is typically an air and oil circulation in the region of the reservoir, which can react on the fluidic valve. This is also prevented by the invention. Are the fluidic valve arranged in or on the pump housing and the discharge channel from the fluidic valve led to the suction through the pump housing and / or pump housing, the pump can be mounted together with fluidic valve as a mounting unit easier and the risk of assembly errors can be reduced because the discharge connection not with must be connected to the support circle. In principle, it is conceivable that the controlled adjusting fluid is fed back directly into the reservoir.

The fluidic valve can be designed separately from the pump housing and, when the pump is arranged in a fluid conveying circuit, can be arranged away from the pump housing or on the pump housing. However, as already mentioned, the fluidic valve is preferably an integral part of the pump in that the pump housing also forms the housing for the fluidic valve. The pump housing can in particular form the valve space for the control piston. With the fluidic valve integrated or mounted on the pump housing, the pump housing can form the pressure connection, the working connection and the discharge connection of the fluidic valve. The preferred discharge channel may extend to the pump housing and / or in the pump housing, so that no additional connection for the pressure relief must be made with integrated or attached to the pump housing fluidic valve. The pump, including the fluidic valve form a mounting unit, so that automatically with the assembly of the pump housing in the fluid conveying circuit and the fluidic valve is at least mechanically mounted. With regard to the assembly in the delivery circuit is also advantageous if the connections for the three mentioned connections of the fluidic valve are formed in and / or on the pump housing and it requires no connection line and no connection for the actuating fluid detached from the pump housing. For example, the actuating fluid for the pressure connection can be branched off from the main flow in the pump housing at its high pressure side. However, if the actuating fluid diverted on the high pressure side downstream of the pump housing Preferably, the branch is located downstream of a filter for cleaning the fluid to supply purified actuating fluid to the fluidic valve.

The control fluid for the fluidic valve may also be diverted from the high pressure side of the pump. Specifically, the control fluid may be diverted downstream of a filter for purifying the fluid delivered by the pump to supply purified fluid to a control chamber formed on the control piston. Advantageously, the branch downstream of the filter can be used to precisely control the pressure used in an internal combustion engine for the fluid supply. Varying pressure losses, for example via a cooler and / or a filter, are irrelevant. In principle, however, the control fluid can be diverted on the high pressure side still within the pump housing.

The actuating fluid controlled by the fluidic valve can in particular also form the control fluid for actuating the fluidic valve, in that the actuating fluid guided via the pressure port into the valve chamber of the fluidic valve at the same time also generates a control pressure acting on the control piston. The pressure connection can accordingly also form a control connection of the fluidic valve.

The solenoid valve has a signal port for connection to an external controller, such as a motor controller. The signal connection of the solenoid valve or a magnetic force counteracting the tensioning device of the solenoid valve is preferably provided for setting a piston position, in which the working port of the solenoid valve and thus the second actuating chamber is connected to the pressure port of the solenoid valve. The clamping force of the clamping device of the solenoid valve is preferably provided for setting a piston position in which the working port of the solenoid valve and thus the second actuating chamber is connected to the discharge port of the solenoid valve. The solenoid valve may also be arranged in or on the pump housing, that is integrated. Alternatively, however, the solenoid valve may readily be located a distance away from the pump housing, which may be particularly advantageous if an electrical connection line would have to be guided by oil in the arrangement in or on the pump housing. By "provided" is intended to be understood in particular specially programmed, designed, designed, configured, equipped and / or arranged.

The pump is in preferred embodiments to a positive displacement pump. In positive displacement pumps, the delivery volume increases proportionally to the conveying speed of the delivery rotor, if no measures adjusting the delivery volume are taken. If the pump is preferably a rotary pump, the delivery volume increases with the rotational speed of the delivery rotor which is rotatable about a rotation axis in the delivery chamber in the case of a rotary pump. Basically, however, the invention also relates to Linearhubpumpen. The delivery volume is therefore, in general terms, proportional to the stroke frequency, the Drehhub- or Linearhubfrequenz, the pump. With positive displacement pumps, this is also referred to as the specific delivery volume, the delivery volume per rotary stroke or linear stroke. Proportionality is troublesome in many applications, especially when the speed at which the pump is driven can not be adjusted to the needs of the unit to be supplied. For example, pumps used in vehicles, such as lubricating oil pumps, power-assisted pumps such as transmission pumps, and coolant pumps, are in many cases driven mechanically by the vehicle's propulsion engine. The drive speed of the pump in these applications depends on the speed of the drive motor and is usually in a fixed speed relationship to the speed of the drive motor. The invention is particularly directed to such applications.

The adjusting device is set up in preferred embodiments for adjusting the specific delivery volume of a positive displacement pump. In the prior art discussed at the beginning, positive displacement pumps and adjusting devices, such as the invention in particular, are disclosed. In addition to the vane pumps and external gear pumps described therein, the invention also relates to adjustable internal gear pumps and pendulum slide pumps in the delivery volume and, in principle, also other pump types which can be adjusted in the delivery volume.

The adjusting device may in particular comprise an adjusting member which cooperates with the conveying rotor or, in the case of pumps having a plurality of conveying rotors, with at least one of the plurality of conveying rotors for adjusting the conveying volume. If the pump is designed as a vane pump with a conveying rotor rotatable in the delivery chamber, the adjusting member may in particular be an adjusting ring surrounding the delivery rotor, which is arranged to be linearly movable or pivotable in the pump housing, so that during an adjusting movement of the adjusting member the eccentricity between the axis of rotation the delivery rotor and a central longitudinal axis of the adjusting ring and thereby the delivery volume is adjusted. Similarly, the delivery volume of internal gear pumps and pendulum slide pumps can be adjusted. In an internal gear pump, in particular the internally toothed ring gear can form the adjusting member and can be arranged to be linearly movable or pivotable for the adjustment. If the pump is designed as an external gear pump, it has at least two conveyor rotors, which are toothed on the outer circumference, so-called external gears. The external gears are meshed with each other. To adjust the specific delivery volume of one of the outer gears is axially adjustable relative to the other, so that the engagement length of the outer gears and thereby the delivery volume of the pump can be adjusted. The adjustable external gear is part of an axially displaceable adjusting unit comprising axially displaceable piston, between which the adjustable external gear is rotatably mounted. The interconnected pistons form the adjustment of the adjustment in such pump designs.

Advantageous features of the invention are also described in the subclaims and in the combinations of the subclaims.

Figur 1

eine im Fördervolumen verstellbare Pumpe mit einem Verstellorgan und mehreren Stellkammern zur Beaufschlagung des Verstellorgans mit unter Druck stehendem Stellfluid,

Figur 2

die Pumpe mit zugeordneten Ventilen zur Verstellung des Fördervolumens und einer Fördercharakteristik der Pumpe, und

Figur 3

eines der zugeordneten Ventile in einem Längsschnitt.

Hereinafter, an embodiment of the invention will be explained with reference to figures. The features disclosed in the exemplary embodiment advantageously each individually and in each combination of features, the objects of the claims and the embodiments described above and also the objects of the aspects advantageously. Show it:

FIG. 1

an adjustable in the flow pump with an adjusting member and a plurality of adjusting chambers for acting on the adjusting with pressurized actuating fluid,

FIG. 2

the pump with associated valves for adjusting the delivery volume and a delivery characteristic of the pump, and

FIG. 3

one of the associated valves in a longitudinal section.

FIG. 1 shows a pump 1, for example in vane-type. The pump 1 comprises a pump housing with a housing structure 2 and a lid. The housing structure 2 accommodates components of the pump and / or supports components of the pump 1 movable. The housing structure 2 is open at an axial end face, whereby the arrangement of components of the pump in or on the housing structure 2 is facilitated. The lid is mounted on the housing structure 2 and closes in the assembled state at the relevant end face the housing structure 2. The cover is in FIG. 1 removed, so that in the illustrated plan view of the open housing structure 2 functional components of the pump can be seen.

The housing structure 2 surrounds a delivery chamber 5 in which a delivery rotor 10 is rotatably arranged about an axis of rotation R ₁₀ . The pump housing has on a low-pressure side a housing inlet for connecting the pump 1 to a reservoir R and on a high-pressure side a housing outlet for the removal of a fluid to be pumped, for example engine lubricating oil, to an aggregate to be supplied with the fluid. The delivery chamber 5 includes a low pressure side and a high pressure side. In a rotational drive of the conveyor rotor 10 in the illustrated direction of rotation, counterclockwise, fluid flows through the housing inlet into the pump housing and the pump housing on the low pressure side through a feed chamber inlet 4 in the delivery chamber 5 and is increasing the pressure on the high pressure side of the pump by a Förderkammerauslass 6 ejected and discharged via the housing outlet. In the pump housing, a suction region is formed on its low-pressure side, through which the fluid conveyed by the pump flows on its flow path from the housing inlet to the delivery chamber inlet 4. The suction region extends into the delivery chamber 5 and also still includes the region of the delivery chamber 5 in which the delivery cells 10 increase as the delivery rotor 10 rotates. On the path of the flow, a high-pressure region of the pump housing, which encompasses the region of the delivery chamber 5 in which the delivery cells shrink, and which extends from this subregion of the delivery chamber 5 via the delivery chamber outlet 6 up to and including the housing outlet, adjoins the suction region.

The conveyor rotor 10 is an impeller with a central rotor structure 11 with respect to the axis of rotation R ₁₀ and vanes 12 distributed over the circumference of the rotor structure 11. The vanes 12 are radially or at least substantially open in slots of the rotor structure 11 open to the outer circumference of the rotor structure 11 Slidably guided radially sliding direction. Radially inside the wings 12 are supported on a transverse to the rotation axis R ₁₀ movable support structure 13.

The conveyor rotor 10 is surrounded at its outer periphery by an adjusting member 20, which is exemplified as an adjusting ring. Slide with rotary drive of the conveyor rotor 10 the rotation axis R _{10 of} the conveyor rotor 10 is arranged eccentrically to a parallel, with respect to the inner peripheral surface of the adjusting central axis 20, so that formed by the conveyor rotor 10 and the adjusting member 20 conveying cells upon rotation of the Increase delivery rotor 10 on the low pressure side of the delivery chamber 5 in the direction of rotation and reduce again on the high pressure side. Due to this with the speed of the conveyor rotor 10 periodic increase and decrease in the delivery cells, the fluid from the low pressure side to the high pressure side and there with increased pressure through the delivery chamber outlet 6 and then through the housing outlet promoted.

The per volume revolution of the conveyor rotor 10 funded fluid volume, the so-called specific delivery volume can be adjusted. If the fluid is a liquid and thus incompressible to a good approximation, the absolute delivery volume is directly proportional to the speed of the delivery rotor 10. For compressible fluids, such as air, the relationship between flow rate and speed is not linear, but the absolute flow rate or mass also increases with the speed.

The specific delivery volume depends on the eccentricity, ie the distance between the central axis of the adjusting member 20 and the axis of rotation R _{10 of} the conveyor rotor 10. In order to change this center distance, the adjusting member 20 is movably arranged in the pump housing, for example, pivotable about a pivot axis R ₂₀ . In variations, a modified adjusting member in the pump housing can also be arranged linearly movable. To adjust the specific delivery volume or the eccentricity, a mobility transverse to the axis of rotation R _{10 of} the conveyor rotor 10 is preferred. In principle, an axial adjustability would also be conceivable by which an axial width of the delivery cells can be adjusted.

A pivot bearing portion of the adjusting member 20 is designated 21. The pivot bearing is designed as a sliding bearing by the adjusting member 20 is in its pivot bearing portion 21 with a mating surface of the housing structure 2 directly in sliding contact.

For the adjustment in a direction V, in the exemplary embodiment pivoting direction, the adjusting member 20 is acted upon by a control pressure of a control fluid. The fluidic actuating pressure counteracts a restoring force in the opposite direction, the return direction. The restoring force is provided by a spring device 25 with one or more mechanical spring members, in the embodiment generates a single spring member. The spring member is designed and arranged as a helical compression spring. For the pressurization with the actuating fluid, the adjusting member 20 on its viewed from the pivot axis R ₂₀ on the axis of rotation R _{10 of} the conveyor rotor 10 opposite side on a functionally acting as an adjusting Verstellorgan-Einwirkbereich 22. To one side of the adjusting member-Einwirkbereichs 22 a first actuating chamber K _{1 is} formed in the pump housing into which the actuating fluid can be introduced to exert on the Verstellorgan-Einwirkbereich 22 and thus on the adjusting member 20 acting in the direction of adjustment V first actuating force. The restoring force of the spring device 25 also acts, for example, directly on the adjusting member-action region 22.

The first control chamber K ₁ is fed with the pumped by the pump 1 actuating fluid to pressurize the adjusting member 20 against the force of the spring means 25 in the direction V with the first control pressure. The adjustment direction V is chosen so that the eccentricity between the conveyor rotor 10 and adjusting member 20 and thereby reduces the specific delivery volume of the pump 1, when the adjusting member 20 moves in the direction of adjustment V.

The adjusting member 20 forms with the housing structure 2 a sealing gap which separates the first actuating chamber K ₁ in the direction of adjustment V from the low-pressure region. In the sealing gap, a sealing element 24 is arranged for better sealing of the sealing gap. The sealing element 24 is arranged in a receptacle of the adjusting member 20.

In the pump housing, a second actuating chamber K _{2 is} formed, in which also a control fluid can be introduced under pressure to be able to exert on the adjusting member 20 in the second control chamber K _2, a second, second control pressure. The adjusting chambers K ₁ and K ₂ are formed on an outer circumference of the adjusting member 20 in the circumferential direction next to each other and sealed from each other by means of another sealing element. In the two actuating chambers K ₁ and K _2, the respective actuating fluid acts directly on the adjusting member 20. In modified embodiments, instead of a direct pressurization, indirect loading of the adjusting member 20 with two or more adjusting pistons could be provided, with the first actuating pressure acting on at least one such adjusting piston and would act on at least one other actuator piston, the second control pressure. The adjusting device may comprise a further adjusting chamber, possibly also a plurality of further adjusting chambers, in which or a control fluid directly or indirectly indirectly acts on the adjusting member 20 via a respective adjusting piston.

The first control pressure prevailing in the first control chamber K ₁ and the second control pressure prevailing in the second control chamber K ₂ are variable by the control chambers K ₁ and K ₂ each being acted upon by an associated valve with the respective control fluid. One of the actuating chambers K ₁ and K ₂ is acted upon by a fluidic valve with actuating fluid, while the other of the actuating chambers K ₁ and K _{2 is} acted upon by a solenoid valve with actuating fluid. In the exemplary embodiment, the fluidic valve of the first actuating chamber K ₁ and the solenoid valve of the second actuating chamber K _{2 is} assigned.

In FIG. 2 is shown a pump 1 containing fluid conveying circuit. The pump 1 is shown schematically as the other components of the fluid circuit. So belong to the pump 1, as out FIG. 1 can be seen, the adjusting device with the adjusting member 20, the spring means 25 and the adjusting chambers K ₁ and K _2nd The fluidic valve 30 is also an integral part of the pump housing in preferred embodiments in that the fluidic valve 30 is arranged in or on the pump housing. The solenoid valve 40 is also considered as belonging to the pump 1, although the solenoid valve 40 may be located a distance from the pump housing. An external arrangement relative to the pump housing may be particularly advantageous if the electrical insulation of a supply line for electrical energy and / or control signals in the immediate vicinity of the pump housing causes problems.

The pump 1 delivers fluid from a reservoir R to an aggregate M to be supplied with the fluid, for example lubricating oil, to an internal combustion engine forming the unit M for driving a motor vehicle. An aggregate M to be supplied with the fluid, which is formed by an internal combustion engine, can drive the pump 1, as in FIG FIG. 2 illustrated so that the conveying rotor 10 is rotationally driven in fixed speed relation to an output shaft of the unit M. On the low-pressure side, the pump 1 conveys the fluid from the reservoir R through a supply line, the housing inlet and the suction region of the pump housing into the delivery chamber 5 (FIG. Fig. 1 ) from which it is ejected with increased pressure. On the high pressure side, a pumped by the pump 1 main flow 50 is conveyed to the unit M. After flowing through the unit M, the fluid flows in pressure relieved back into the reservoir R.

From the main flow 50, a smaller part is branched off and guided as actuating fluid to a pressure port P of the fluidic valve 30. The pressure port P is connected via a bypass line to the main flow 50 accordingly. The fluidic valve 30 is connected via a working port A to the first actuating chamber K ₁ (FIG. Fig. 1 ) connected. The adjusting member 20 is in FIG. 2 representative of the other components of the adjusting device, such as the spring device 25 and the adjusting chambers K ₁ , K ₂ and optionally one or more further adjusting chambers.

The fluidic valve 30 further includes a discharge port S for the actuating fluid. The discharge port S is connected via a discharge channel 35 directly to the suction region of the pump housing. The reservoir R is bypassed. The relief channel 35 preferably extends in or on the pump housing directly from the fluidic valve 30 to directly into the suction region of the pump housing. Through the discharge port S, no fluid flows directly to the reservoir R, and no fluid flows from the reservoir R through the discharge port S to the fluidic valve 30. There is therefore no direct fluid connection between the discharge port S and the reservoir R. The pressurized actuating fluid is energy-efficiently returned to the suction area of the pump housing via the discharge port S. The pump 1 does not have to suck in again from the reservoir R to relieve the pressure of the adjusting member 20. The trapped recirculating fluid has a higher pressure than the fluid in the reservoir R and contains less air. Both contribute to the improvement of the efficiency of the pump 1.

Although a pressure relief in the suction region of the pump housing against a pressure relief in the reservoir R offers a whole series of advantages, the fluidic valve 30 can be relieved of pressure via its discharge port S to the reservoir R in modified embodiments.

The fluidic valve 30 is actuated with a likewise branched off from the high pressure side of the pump 1 control fluid, which is guided to a control port C of the fluidic valve 30.

The solenoid valve 40 may be a proportional valve with which the control pressure in the second control chamber K ₂ (FIG. Fig. 1 ) can be adjusted continuously. In particular, however, it may also be a multi-way switching valve which is between two, three or optionally also more switching states and thus piston positions can be switched. In the exemplary embodiment is such a switching valve that connects the second actuating chamber K ₂ in a first switching state with the high pressure side of the pump 1 and in a second switching state of the high pressure side of the pump 1 and instead via a return line 45, bypassing the reservoir R. with the low pressure side of the pump 1 connects. In the first switching state of the solenoid valve 40, the second actuating chamber K _{2 is} therefore connected to the high pressure side of the pump 1 and in the second switching state with its low pressure side. If the solenoid valve 40 assumes the first switching state, the actuating pressures in the actuating chambers K ₁ and K _{2 act} together on the adjusting element 20. If the solenoid valve 40 assumes the second switching state, only the actuating pressure in the first actuating chamber K ₁ acts on the adjusting element 20 while in the second actuating chamber K _2, the comparatively low pressure of the suction region of the pump housing prevails. Accordingly, this first control pressure must be higher in order to move the adjusting member 20 against the restoring elastic force of the spring device 25 in the direction of adjustment V.

Also applies to the solenoid valve 40 that its discharge port S is preferably connected directly to the suction of the pump housing, but that an alternative pressure relief of the solenoid valve 40 in the reservoir R should not be excluded.

The solenoid valve 40 has a signal port 41 where it is connected to an external controller. If the unit M is a drive motor of a vehicle, in particular a motor control can form the external control. Such engine controls are typically formed as characteristic or map controls. In an engine map control, the demand of the drive motor in a map of different engine sizes, such as an engine temperature and / or an engine speed and / or a lubricating oil pressure at a critical point of the engine and / or the load state of the engine and the like stored in an electronic memory of the controller his. On the basis of corresponding measured variables and the stored characteristic map, the external control unit forms the output signal with which it activates the solenoid valve 40 in order to modulate the delivery pressure of the pump 1. The modulation is that by means of the solenoid valve 40, the size of that discharge pressure can be changed, when it reaches the specific delivery volume of the pump 1 is reduced by adjusting the adjusting member 20.

In FIG. 3 the fluidic valve 30 is shown in a longitudinal section. Recognizable are the ports A, P and S for the actuating fluid and the port C for the control fluid. The fluid valve 30 is an integral part of the pump 1 in that the pump housing also forms the housing of the fluidic valve 30. The pump 1 can be mounted as a unit including the fluidic valve 30. The conveying and adjusting components, such as in particular the conveying rotor 10 and the adjusting member 20, and the fluidic valve 30 are combined by means of the common pump housing to form a mounting unit.

The valve chamber 31 is formed in the housing structure 2, for example as an axial blind bore. It is open at one of the two ends of the control piston 32. A closure member 37 closes the valve space 31 at the open end. In an axial end region of the valve chamber 31, a clamping chamber 34 is formed, in which the clamping device 33 acts on the control piston 32.

The discharge channel 35 ( FIG. 2 ) opens into the clamping chamber 34, so that the clamping chamber 34 in each state of the fluidic valve 30, that is, regardless of the position of the control piston 32, is connected to the suction region of the pump housing. In the FIG. 3 extends the discharge channel perpendicular to a displacement axis of the control piston 32 from the clamping chamber 34. Alternatively or additionally, the discharge channel can extend obliquely, parallel or in extension to the displacement axis of the control piston 32 from the clamping chamber 34.

The control piston 32 is reciprocable in the valve space 31 between a first piston position and a second piston position. In FIG. 3 the control piston 32 assumes the second piston position. In the second piston position of the working port A is connected to the discharge port S. The actuating fluid can flow via the working port A into the valve chamber 31 and flow out of this via the discharge port S into the suction region of the pump housing. The first actuating chamber K ₁ is in this state of the fluidic valve 30, with the control piston 32 located in the second piston position, under the comparatively low pressure of the suction region, whereby an effective pressure relief of the adjusting member 20 is achieved.

The control piston 32 moves from the second piston position to the first piston position, in FIG FIG. 3 to the right, the pressure port P is connected to the working port A and via this with the first control chamber K ₁ , so that the adjusting member 20 with the control pressure, a pressure of the high pressure side of the pump 1, is applied. The adjusting device is designed so that an increase in the setting pressure causes a reduction of the specific delivery volume of the pump 1.

The in the picture of the FIG. 2 at the fluidic valve 30 drawn control terminal C, as in FIG. 3 recognizable be summarized with the pressure port P. Accordingly, the pressure port P can also simultaneously form the control port C. A control chamber 36 formed in the valve chamber 31, in which the control piston 32 is acted upon by the clamping force of the tensioning device 33 against the fluidic control force, also forms a connection chamber for the connections P and A when the control piston 32 is in the first piston position.

The fluidic valve 30 is permanently connected with its inlet C to the high-pressure side of the pump 1. On the control piston 32 acts during operation of the pump 1 is constantly a control pressure and thus a control force against the clamping device 33. The clamping device 33 of the fluidic valve 30 is biased. It permanently exerts a force acting against the control force clamping force on the control piston 32, which is greater than a maximum occurring at proper function and active control of the solenoid valve 40 acting on the control piston 32 control force. A properly functioning and active solenoid valve 40 controls the pump 1 during operation via the second control chamber K ₂ in the manner so that a maximum of a control piston acting on the control force 32 results, which is smaller than the clamping force of the clamping device 33 of the fluidic valve 30 and thus smaller than the control force necessary for switching the first switching position and thus the first piston position. The fluidic valve 30 is always switched in its second switching position and thus in the second piston position in operating states in which the solenoid valve 40 is functioning properly and active, since the solenoid valve 40 controls the pump 1 to a maximum flow rate through the one on the control piston 32 resulting from the maximum flow rate acting on the control piston 32 of the fluidic valve 30 control force is not sufficient to the fluidic valve 30 from the second switching state to the first switching state to switch or to move the control piston 32 from the second piston position to the first piston position.

The control force acting on the control piston 32 and the clamping force of the tensioning device 33 of the fluidic valve 30 alone do not determine the switching position of the fluidic valve 30 when the solenoid valve 40 is functioning properly and actively. The control force acting on the control piston 32 and the tensioning device 33 give the fluidic valve 30 a fail -Safe property in case of failure of the solenoid valve 40. The force acting on the control piston 32 control force and the clamping device 33 serve as backup loading of the adjusting member 20 in the event that the solenoid valve 40 or the associated control device fails due to a defect, for example due to a cable break or a disconnected electrical connector, or when the solenoid valve 40 is deactivated in certain operating conditions. The fluidic valve 30, in particular the clamping device 33, is designed so that in the event of failure or deactivation of the solenoid valve 40, the delivery volume of the pump 1 is displaced from maximum to minimum only upon reaching a pump outlet pressure which is greater than a maximum pump outlet pressure, the occurs with proper and active operation of the solenoid valve 40, and is less than a pump output pressure, which would lead to damage of at least one component. The fluidic valve 30 and the first control chamber K ₁ serve as Schutzabregelung the pump 1 when the solenoid valve 40 fails due to a defect or deactivation.

The control piston 32 has a first annular portion 51 and a second annular portion 52, which are axially spaced from each other. The first ring section 51 fluidly separates the control chamber 36 and the clamping chamber 34 from each other. In the second piston position, the first annular section 51 separates the pressure port P and the working port A, thereby connecting the discharge port S to the working port A. In the first piston position, the first annular section 51 separates the working port A and the discharge port S, thereby connecting the pressure port P with the working port A. The first ring portion 51 has a single sealing surface, which is designed in the circumferential direction and axially continuous and thus uninterrupted. The first ring portion 51 bears with its sealing surface sealingly against the housing structure 2. It has a constant diameter. The first ring portion 51 is formed as a solid body and thus not hollow.

The second ring portion 52 is disposed in the control chamber 36. The second ring portion 52 is disposed axially between the pressure port P and the inlet C and the first ring portion 51, respectively. The second ring portion 52 has axial through holes 53 fluidly connecting the pressure port P and the inlet C to the first ring portion 51. With this, the through holes 53 connect a control surface of the first ring portion 51 to the pressure port P and the inlet C. The through holes 53 are formed as bores. The first ring portion 51 has a diameter which is smaller than the diameter of the second ring portion 52, whereby a correct mounting of the control piston 32 can be ensured. In principle, it is conceivable for the first ring section 51 to have a diameter which is greater than the diameter of the second ring section 52. The housing of the fluidic valve 30 has a stepped design in its inside diameter. The housing of the fluidic valve 30 has two different in their inner diameter areas. The ring sections 51, 52 each abut with their diameter on the inner diameter of the housing. To form the housing of the fluidic valve 30, the housing structure 2 has a stepped bore. The housing structure 2 forms the housing of the fluidic valve 30.

For the arrangement of the clamping device 33, the control piston 32 has a first axial projection 54 on which the clamping device 33, in particular the coil spring, is arranged or plugged. The first axial projection 54 forms a spring seat. The tensioning device 33, in particular the helical spring, surrounds the first axial projection 54. The first axial projection 54 extends axially from the first ring section 51 into the tensioning chamber 34. The tensioning device 33, in particular the helical spring, is supported at one end on the first ring section 51 off.

To form a stop for the second piston position, the control piston 32 has a second axial projection 55 at a second axial end. The second axial projection 55 forms a stop in the second piston position, in which the pressure port P and the working port A are separated from each other. The second axial projection 55 abuts in the second piston position on a counter-stop. The counter-stop is formed by the closure part 37. The second axial protrusion 55 extends axially from the second annular portion 52 toward the closure portion 37. The axial protrusions 54, 55 have a diameter that is smaller than the diameters of the annular portions 51, 52, respectively.

Claims (14)

1. A pump which exhibits an adjustable delivery volume, the pump (1) comprising:

   (a) a pump housing (2) comprising a delivery chamber (5) which comprises a delivery chamber inlet (4) on a low-pressure side of the pump (1), and a delivery chamber outlet (6) on a high-pressure side of the pump, for a fluid;

   (b) a delivery rotor (10) which can be rotated about a rotary axis (R₁₀) within the delivery chamber (5), for delivering the fluid;

   (c) an adjusting device, comprising:

   (c1) an adjusting member (20) which can be adjusted back and forth in the pump housing (2) in a setting direction (V) and a restoring direction in order to adjust the delivery volume of the pump (1);

   (c2) a first setting chamber (K₁) for generating a first setting pressure for adjusting the adjusting member (20);

   (c3) and a second setting chamber (K₂) for generating a second setting pressure for adjusting the adjusting member (20); and

   (c4) a restoring device (25), arranged in the pump housing (2), for generating a restoring force which acts on the adjusting member (20) in a restoring direction;

   (d) a fluidically operable valve (30) for adjusting the setting pressure of the first setting chamber (K₁);

   (e) and an electromagnetic valve (40), comprising: a pressure port (P) for a setting fluid which is diverted from the high-pressure side; and a relief port (S) for the setting fluid,

   (f) wherein the electromagnetic valve (40) comprises a working port (A) for the setting fluid, which is connected to the second setting chamber (K₂), in order to adjust the setting pressure of the second setting chamber (K₂),
   characterised in that

   (g) the first setting pressure and the second setting pressure acts or respectively act on the adjusting member (20) in the setting direction (V), and

   (h) the fluidically operable valve (30) is permanently connected to the high-pressure side of the pump (1), hence a control force resulting from the control fluid is permanently acting against the tensing device of the fluidically operable valve.
2. The pump according to the preceding claim, wherein the fluidically operable valve (30) comprises: a pressure port (P) for a setting fluid which is diverted from the fluid of the high-pressure side; a working port (A), connected to the first setting chamber (K₁), for the setting fluid; and a relief port (S) for the setting fluid.
3. The pump according to any one of the preceding claims, wherein the relief port (S) of the fluidically operable valve (30) of Claim 2 and/or the relief port (S) of the electromagnetic valve (40) is/are connected to the low-pressure side of the pump (1), preferably directly connected to a suction region of the pump housing (2), at a point downstream of a reservoir (R) for the fluid.
4. The pump according to any one of the preceding claims, wherein the fluidically operable valve (30) comprises: a valve space (31); a control piston (32) which can be moved back and forth within the valve space (31) between a first piston position and a second piston position; a tensing device (33) for generating a tensing force which acts on the control piston (32) in the direction of one of the piston positions; and a control chamber (36) for generating a control force which acts on the control piston (32) counter to the tensing force of the tensing device (33); and the control chamber (36) comprises an inlet (C), which is permanently attached to the high-pressure side of the pump (1), for a control fluid.
5. The pump according to Claim 4, wherein the tensing device (33) of the fluidically operable valve (30) exerts a tensing force which is greater than a control force which occurs when the electromagnetic valve (40) is properly and/or actively functioning.
6. The pump according to Claim 4 or 5, wherein the control piston (32) comprises at least a first annular portion (51), which separates the pressure port (P) and the working port (A) from each other in one piston position and separates the working port (A) and the relief port (S) from each other in another piston position, and a second annular portion (52) which comprises at least one passage opening (53) and is arranged axially between the pressure port (P) and the first annular portion (52).
7. The pump according to Claim 6, wherein one axial end of the control piston (32) comprises a first axial protrusion (54) for arranging the tensing device (33), and another axial end of the control piston (32) comprises a second axial protrusion (55) for forming an abutment.
8. The pump according to Claim 6 or 7, wherein at least the first annular portion (51) is formed as a solid body.
9. The pump according to any one of Claims 6 to 8, wherein the annular portions (51, 52) differ from each other in their diameter.
10. The pump according to any one of Claims 4 to 9, wherein the pressure port (P) of the fluidically operable valve (30) also forms the inlet (C) into the control chamber (36) of the fluidically operable valve (30).
11. The pump according to any one of the preceding claims, wherein the fluidically operable valve (30) comprises a housing which comprises at least two regions which differ from each other in their inner diameter.
12. The pump according to any one of the preceding claims, wherein the electromagnetic valve (40) comprises: a valve space; a control piston which can be moved back and forth within the valve space between a first piston position and a second piston position; a tensing device (43) for generating a tensing force which acts on the control piston in the direction of one of the piston positions; and an electromagnetic device (46) for generating an electromagnetic force which acts on the control piston counter to the tensing force of the tensing device (43); and the electromagnetic device (46) comprises a port (41) for connecting to an external controller, preferably an engine controller.
13. The pump according to Claim 12, wherein the tensing device (43) of the electromagnetic device (46) is provided for setting a piston position in which the second setting chamber (K₂) is connected to the relief port (S) of the electromagnetic device (46).
14. The pump according to any one of the preceding claims, wherein the pump (1) is arranged in a fluid cycle, and a filter (48) for cleaning the fluid delivered by the pump (1) is arranged in the fluid cycle at a point downstream of the pump (1), and the setting fluid for at least one of the setting chambers (K₁, K₂) and/or the control fluid for the fluidically operable valve (30) is/are diverted at a point downstream of the filter (48).

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