EP3173624A2 - Adjustment valve for adjusting the supply volume of a pressure pump - Google Patents

Abstract

Displacement pump with adjustable delivery volume in order to supply an internal combustion engine driving the motor vehicle with lubricating oil, the positive displacement pump with an adjustment valve (20) comprising: a valve housing (21), - A in the valve housing (21) movably mounted valve piston (22) having an active surface (23) for a Ventilstelldruck (P 20) of a fluid, - a valve spring (25), one of the valve actuating pressure (P 20) on the valve piston ( 22) counteracts applied force, an adjusting device (27, 28) by means of which the valve piston (22) is adjustable in the direction of the force exerted by the valve actuating pressure (P 20) or against this force, wherein the valve piston (22) has a further active surface (24) for the valve set pressure (P 20) and the active surfaces (23, 24) arranged counteracting each other and are different in size to the size difference of the active surfaces (23, 24) accordingly to generate a counteracting force on the valve piston (22) of the valve spring (25) counteracting differential force.   

Description

The invention relates to an adjustment valve for the adjustment of the delivery volume of a positive displacement pump and a positive displacement pump with the adjustment valve, which is arranged for the adjustment of the delivery volume of a fluid to be delivered by the pump in a fluid circuit of the pump. The invention accordingly also relates to the adjustment valve as such, as far as it is provided for the adjustment of the delivery volume of a positive displacement pump.

Positive displacement pumps deliver fluids at a volume flow proportional to the pump speed. The delivery volume per revolution or reciprocating stroke, the so-called specific volume flow, is constant or, in practice, can be regarded as constant, at least to a good approximation. The constancy per revolution or stroke and, accordingly, the proportionality to the pump speed is troublesome, for example, in applications in which the unit to be supplied by the respective pump has a fluid requirement which is lower in one or more speed range (s) of the pump than that from the Proportionality resulting volumetric flow. Accordingly, in the respective speed range, the pump delivers a volume flow above the demand, which is dissipated with loss. The problem is in the US 6 126 420 B described that already discloses an internal gear pump with adjustable delivery volume to solve the problem.

The US Pat. No. 6,244,839 B1 also discloses an internal gear pump with adjustable delivery volume. For the adjustment, the inner gear is axially displaceable relative to the outer gear. The inner gear is part of an axially displaceable adjusting unit, which is formed as a double-acting piston. The adjusting unit is acted upon by a 4/3-way adjusting valve with the pumped fluid from the pump. The adjustment valve has a valve housing and a valve piston axially reciprocating valve piston which is acted upon at one axial end with the funded fluid and at the other axial end with a pressure of the fluid counteracting force of a valve spring. The position of the valve piston is adjusted according to the Balance the force of the valve spring and the force generated by the fluid pressure. The adjustment valve is designed so that the adjustment of the pump moves when reaching a predetermined by the valve spring fluid pressure from an axial position for maximum delivery volume toward an axial position for minimum delivery. The preload force of the valve spring is adjusted at the adjustment valve in advance.

From the WO 03/058071 A1 a positive displacement pump with an adjusting valve is known, the movable valve piston for adjusting the delivery volume of the pump in an axial direction with fluid of the high pressure side of the pump and the fluid counteracting acted upon by a spring force. In order to be able to lower the fluid pressure at which the pump is stopped, a control device is provided for the adjusting valve, which exerts an additional force on the valve piston. As examples of control means, an electric stepping motor for adjusting the biasing force of the valve spring and a magnetic coil for generating an additional magnetic force are called. The switched by means of the adjustment fluid flow acts on a displacement unit of the pump only in the direction of maximum delivery volume, while in the opposite direction always the pressure of the high pressure side acts.

It is an object of the invention to adapt the delivery volume of a positive displacement pump flexibly and precisely to the requirements of an aggregate to be supplied and to always ensure an adequate supply of the aggregate.

The invention is based on a positive displacement pump for the supply of an aggregate with fluid, which has a pump housing with a delivery chamber and a delivery member movable in the delivery member, which acts directly on the fluid to convey it through the delivery chamber. When a conveying movement is carried out, the conveying member can convey the fluid alone or in cooperation with one or possibly several further conveying members from an inlet of the conveying chamber while increasing the pressure through an outlet of the conveying chamber. The inlet becomes a low pressure side and the outlet is assigned to a high pressure side of the pump. The pump is preferably arranged in a closed fluid circuit, but in principle can also serve to convey the fluid in an open fluid circuit. When integrated in a closed fluid circuit, it draws the fluid on the low-pressure side from a reservoir through the inlet into the delivery chamber and conveys it on the high pressure side to the or possibly several to be supplied with the fluid unit (s). downstream from the aggregate (s) the fluid returns to the reservoir, closing the fluid circuit. The pump can be used for example for the supply of a hydraulic press with pressurized fluid. In preferred embodiments, it is installed in a motor vehicle or provided for installation in order to supply an internal combustion engine driving the motor vehicle with lubricating fluid or an automatic transmission with hydraulic fluid. Preferably, the internal combustion engine drives the pump.

The displacement pump further comprises an adjustment valve, adjusted by means of which the delivery volume of the pump adapted to the needs of at least one unit to be supplied and the energy required for driving the pump can be preferably reduced accordingly. The adjustment valve comprises a valve housing, a valve piston movable in the valve body, a valve spring and an adjusting device. The valve piston has an active surface for a fluidic valve set pressure. The valve spring is arranged so that it acts counter to the total acting on the valve body valve actuating pressure on the valve piston.

As a delivery volume, the specific volume flow of the pump is understood as such in preferred embodiments, in the case of a rotary pump, the volume flow per revolution and in the case of a reciprocating pump, the flow rate per stroke. Although less preferred, the pump may also be a fixed displacement pump and the adjustment valve may be disposed on the high pressure side of the pump as a bypass valve to deliver excess fluid being conveyed bypassing the at least one unit into the reservoir. Such a bypass conveyance does not reduce the power consumption of the pump, but still ensures demand-based delivery. In such embodiments, it is not the delivery volume at the outlet of the delivery chamber. but the conveyed to the at least one aggregate funded volume controlled or regulated as needed. It is also possible to combine a pump adjustable in its delivery volume with such a bypass valve by adjusting the volume flow per revolution or stroke via an adjusting valve according to the invention or otherwise and downstream of the pump, but upstream of the unit to be supplied, part of the pump the pump funded flow diverted and returned unused to a reservoir.

In preferred embodiments, the delivery volume of the pump as such, as seen directly at the outlet of the delivery chamber, adjusted by means of the adjustment valve. In such embodiments, an actuator is arranged movably in the pump housing, which can be acted upon in the direction of its mobility with a dependent on the need of at least one unit actuating force. The actuator may be arranged in particular to an end face of the conveyor member or the conveyor member surrounding. The actuator and the delivery member are in first variants part of an in the pump housing as a whole back and forth movable adjustment, for example, a linearly movable or pivotable or otherwise movable transversely to a rotation axis of the preferably rotatable conveyor member adjustment. Examples of such adjusting units describe, for example, the US Pat. No. 6,283,735 B1 for outside-axle, the US 6 126 420 B and US Pat. No. 6,244,839 B1 for internal-axis pumps and the EP 1 262 025 A2 for both pump types. In second variants, the actuator is adjustable relative to the conveyor member and the pump housing. The actuator of the second variant may in particular be a collar surrounding the conveyor member, as known from vane pumps including vane pumps, pendulum slide pumps, and also internal gear pumps to adjust the eccentricity to the conveyor member, for example by a linear lifting or pivotal movement of the actuator.

The actuating force is preferably generated fluidically by the actuator forming an actuating piston, which is acted upon by a pressurized fluid. This pressure fluid can be branched off, in particular, on the high-pressure side of the pump and can be returned to the actuator via the adjustment valve as a partial flow of the total volume flow delivered by the pump. However, the pressurized fluid applied to the actuator may in principle also be another fluid, for example a fluid which is provided from a pressure reservoir or from another pump.

In yet another variant, a partial flow of the fluid is conducted via the adjustment valve into the delivery chamber back to the low-pressure side in order to increase the degree of filling of delivery cells there, as described, for example, in US Pat US Pat. No. 6,935,851 B2 is disclosed. Due to the return and filling of the conveyor cells, the delivery volume is also adjusted at the same time, whereby this type of adjustment can also be realized in combination with one of the other types mentioned above.

According to the invention, the adjusting device is formed so that it can adjust the valve piston in the direction of the force exerted by the valve actuating pressure on the valve body or against the valve actuating pressure. It preferably acts electromagnetically. The word "or" here and elsewhere in the sense of the invention includes the meaning of "either ......... or" and also the meaning of "and", as far as the respective context does not necessarily mean a limited one Meaning surrounds. Accordingly, the adjustment means may be designed to counteract or preferably counteract the force of the valve set pressure only in the same direction and the valve spring, and alternatively may be constructed to bias the valve piston both in and against the force of the valve set pressure can adjust.

In a preferred first embodiment, the valve actuating pressure and a force exerted by the adjusting device on the valve piston act together against the force of the valve spring. If the valve actuating pressure increases, the valve piston can be adjusted by means of a correspondingly smaller force of the adjusting device against the force of the valve spring.

In a second preferred embodiment, the adjusting device for adjusting the valve piston is set up both in the direction of the valve set pressure and against the valve set pressure. If the adjustment device is a magnetic adjustment device with only a single magnetic coil, the magnetic coil can be repolished in such embodiments. Alternatively, for each of two directions of movability of the valve piston, a separate solenoid with one armature each may be provided and one of these armatures on the valve piston exert a force in one arm and the other armature force in the other direction of movability of the valve piston to move the valve piston back and forth.

The position of the valve piston can thus be adjusted relative to the valve housing, at least in the second embodiment, but preferably also in the first embodiment, independently of the acting on the effective surface valve actuating pressure, and the delivery volume of the pump can be adjusted accordingly. The adjustment valve can thus set the delivery volume over a larger operating range of the unit to be supplied continuously or arbitrarily adjusted and adjusted not only to a certain pressure, when reached the delivery volume.

Preferably, a control or regulating device for the adjusting valve is arranged so that by means of the adjusting valve, the delivery volume over the entire operating range of the unit is adjusted adjusted. On the other hand, ensure the valve spring and the valve spring constantly counteracting the force of the valve spring secure supply of the unit, albeit in case of failure of the adjustment only as known from conventional positive displacement pumps with a reduction of the delivery volume as a function of the biasing force and spring constants of the valve spring. The invention combines a precise and flexible adaptability to the needs with a guaranteed even in case of failure of the adjustment supply security, it creates a so-called second-level control or regulation for the delivery volume.

The adjustment valve is preferably a proportional valve. It is preferably controlled electrically. The adjusting device preferably acts magnetically. It may comprise a proportional solenoid which is voltage or current controlled or regulated, that is to say by a variation of the applied voltage or current, oriented to the needs of the at least one aggregate. In other preferred embodiments, the adjustment valve is controlled or regulated in a pulse-modulated manner. When using a pulse-modulated adjustment valve, the duration of the individual pulses or the time interval between two successive pulses of the manipulated variable can be varied, which also includes the case that both the pulse duration and the time duration between successive pulses is varied according to demand. The period of the manipulated variable is preferably constant. Preferably, a pulse width modulated adjustment valve is used. The period of the manipulated variable for the adjustment valve is significantly smaller than the time constant of the positive displacement pump which determines the adjustment of the delivery volume. The pulse modulation uses the Tiefpasscharakters the pump. By varying the on-time of the pulse width modulation or the time interval in the case of a pulse frequency modulation adapted to the needs, the flow through the adjustment valve and consequently the displacement of the positive displacement pump can be quasi-continuously controlled or regulated according to the momentary demand of the unit.

The adjustment valve is preferably a multi-way valve with at least three ports, preferably with four ports. It is preferably switchable between at least two switch positions, preferably between three switch positions.

The adjustment valve is controlled or regulated in preferred embodiments depending on a desired value for the volume flow to be delivered by the positive displacement pump or a fluid supply pressure to be generated by the positive displacement pump. A setpoint specification specifies the setpoint value of a control or regulation device provided for the adjustment valve. The set point is preferably varied depending on the demand of the unit. Preferably, a characteristic field is specified for the setpoints dependent on the operating state of the unit. The at least one desired value or more preferably the plurality of desired values is or are predefined as a function of a physical variable characterizing the operating state, which is sensed during operation of the unit by means of a detection device. The at least one physical variable may in particular be a temperature, a rotational speed or a load state of the aggregate. Preferably, the desired value or the desired values for the volume flow or the fluid supply pressure are predefined as a function of at least two variables characterizing the operating state of the unit. If the positive displacement pump is used as a lubricating oil pump for an internal combustion engine, the temperature of the lubricating oil or the cooling fluid in the region of the internal combustion engine or the speed or for the load state can detect or determine the accelerator pedal position or a throttle position, and from this the associated desired value can be determined on the basis of the characteristic field the control or regulating device for the adjustment valve can be specified.

In a preferred first embodiment, the adjustment valve is only controlled as a function of the respective desired value. The detection of an actual value representative of the requirement of the physical quantity forming the desired value, namely of the volume flow or of the fluid supply pressure, is dispensed with, as well as elaborate processing for a control based on a desired / actual comparison.

In a likewise preferred second embodiment, the adjustment valve is regulated as a function of a desired / actual comparison of the respective setpoint value and an actual value of the volume flow or the fluid supply pressure measured continuously or at sufficiently small time intervals. Control is advantageous in cases where the volumetric flow demand of the unit changes due to wear over the life of the unit.

In an optional combination of the two embodiments, a control device is provided which can switch from a controller according to the first embodiment to a control according to the second embodiment. In this case, it is preferred if the adjustment valve is initially controlled on the basis of the predefined volumetric flow and, with increasing leakage losses as a result of wear of the unit, is later converted to pressure regulation. In yet another embodiment, an adaptive control device is provided, which detects increasing wear on the basis of a sensory detection of the volume flow or fluid supply pressure and the setpoint or the setpoint characteristic adjusted at least once or in several stages, possibly continuously during the life of the unit shifts.

In yet a preferred embodiment, the adjustment valve is controlled on the one hand based on a desired value or a setpoint characteristic map for the fluid supply pressure or the volume flow and additionally current-controlled. A particularly preferred embodiment is an adjustment valve controlled by means of a setpoint value or a plurality of desired values or a setpoint characteristic map for the fluid supply pressure or the volume flow by means of pulse width modulation and additionally current-controlled. With the current control changes associated with temperature changes of the electrical resistance of a magnet adjustment advantageously be compensated. It detects the current consumption of the Magnetverstelleinrichtung and compensated for the changes in the size of the electric current due to changes in resistance by the duty cycle of the variation of the current consumption is regulated accordingly. Accordingly, however, not only for the preferred embodiment as pulse width modulated adjustment valve, but also be operated at differently controlled adjustment valves. By a current control in addition to the control of a setpoint or setpoint characteristic map for the flow or the fluid supply pressure can be dispensed with a flow or pressure control, although in the case of a current control additionally a flow or pressure control can be used.

The control or regulating device may be integrated part of the adjusting valve or installed separately from it. The setpoint specification can be embodied component of the control or regulation device or representational separately from the other parts of the control or regulating device. The adjustment valve is preferably an integral part of the positive displacement pump, for example mounted on the pump housing. The adjustment valve can be advantageously arranged in the integrated embodiment in the housing of the positive displacement pump, for example in a receiving bore or a differently shaped receiving space in a wall of the pump housing. The connections of the adjusting valve can be shaped in such embodiments save space and weight as holes or other shaped channels in the housing, in particular in said housing wall. Accordingly, the pump housing can simultaneously also form the valve housing or only part of the valve housing.

In the embodiments in which the delivery volume is adjusted directly to the pump, it is advantageous if the actuator is formed as a double-acting actuator piston with two axially opposite, preferably oppositely facing piston surfaces and by means of the adjustment either one or the other piston surface with a pressurized fluid can be applied, optionally also both piston surfaces simultaneously.

If the actuator forms an actuating piston which can be pressurized with pressurized fluid, for example a piston which can be pressurized only on one side or preferably a double-acting piston, it is acted upon in preferred embodiments by a pump spring with a spring force, the pump spring acting in the direction of increasing the delivery volume of the pump. If the actuator forms a double-acting piston, it is preferred if the pump spring is so weak that the adjustment dynamics of the pump are not significantly influenced by the pump spring, but exclusively or at least to a significant extent by the adjustment valve. In principle, it is also possible to dispense with a pump spring in such embodiments. On the other hand, the use of a weak pump spring is advantageous, wherein such a pump spring is designed so that it only ensures that in low-speed displacement pump, the maximum pumping speed for this pump speed is promoted. Suffice a pump spring, which exerts on the actuator a spring force corresponding to a fluid pressure of at most 1 bar.

Preferably, the fluid controlled by means of the adjustment valve or regulated to the positive displacement pump for the purpose of adjustment or in the case of an adjustment valve used only as a bypass valve generates the fluid branched off to a reservoir at its flow through the adjustment valve. In such embodiments is for the generation of the valve actuating pressure does not require a separate connection. The same inlet, through which the fluid flow flowing through the adjusting valve passes into the adjusting valve, also forms the connection for the fluid which generates the valve actuating pressure.

It is preferred if the valve actuating pressure is generated by means of a plurality of active surfaces, preferably by means of exactly two active surfaces which differ in size, so that the valve actuating pressure exerts a differential force on the valve piston corresponding to the area difference of the active surfaces. Particularly preferably, the feature of the differential force is combined with the further feature, after which the fluid also simultaneously generates the valve set pressure during the flow through the adjustment valve.

In a further development, the biasing force of the valve spring can be adjusted, preferably fluidly while the positive displacement pump delivers the fluid. Thus, the adjustment valve may have a further piston. which preferably serves only to adjust the biasing force and preferably is acted upon by the fluid, which also generates the valve actuating pressure. wherein for the piston for adjusting the biasing force provided a separate connection or preferably a force acting on this adjusting piston force can also be generated by the fluid flowing through.

• Aspekt 1. Verstellventil für die Verstellung des Fördervolumens einer Verdrängerpumpe, das Verstellventil umfassend
  1. a) ein Ventilgehäuse (21),
  2. b) einen in dem Ventilgehäuse (21) beweglich gelagerten Ventilkolben (22) mit einer Wirkfläche (23) für einen Ventilstelldruck (P₂₀) eines Fluids,
  3. c) eine Ventilfeder (25), die einer von dem Ventilstelldruck (P₂₀) auf den Ventilkolben (22) ausgeübten Kraft entgegen wirkt,
  4. d) und eine Verstelleinrichtung (27, 28), mittels der der Ventilkolben (22) in Richtung der vom Ventilstelldruck (P₂₀) ausgeübten Kraft oder gegen diese Kraft verstellbar ist.
• Aspekt 2. Verstellventil nach dem vorhergehenden Aspekt und wenigstens einem der folgenden Merkmale:
  • die Verstelleinrichtung (27, 28) ist elektrisch betätigbar;
  • die Verstelleinrichtung (27, 28) ist als Magnetverstelleinrichtung gebildet;
  • die Verstelleinrichtung (27, 28) wirkt der Kraft der Ventilfeder (25) entgegen.
• Aspekt 3. Verstellventil nach einem der vorhergehenden Aspekte und wenigstens einem der folgenden Merkmale:
  • das Verstellventil (20) ist ein Proportionalventil;
  • das Verstellventil (20) wird pulsmoduliert, vorzugsweise pulsweitenmoduliert, gesteuert oder geregelt;
  • das Verstellventil (20) wird stromgesteuert oder -geregelt;
  • das Verstellventil (20) wird spannungsgesteuert oder -geregelt;
  • das Verstellventil (20) weist wenigstens drei Anschlüsse (I, O, A, B), vorzugsweise vier Anschlüsse für das Fluid auf;
  • das Verstellventil (20) ist zwischen wenigstens zwei Schaltstellungen, vorzugsweise drei Schaltstellungen umschaltbar;
  • das Verstellventil (20) ist ein Wegeventil.
• Aspekt 4. Verstellventil nach einem der vorhergehenden Aspekte, umfassend
  • eine Steuerungs- oder Regelungseinrichtung für die Steuerung oder Regelung eines von der Verdrängerpumpe zu erzeugenden Fluidversorgungsdrucks (P₁₄) oder zu fördernden Volumenstroms (V₁₄)
  • und eine Sollwertvorgabe für die Vorgabe wenigstens eines Druck- oder Volumenstrom-Sollwerts, vorzugsweise eines in vorgegebener Weise variablen Sollwerts,
  • wobei die Steuerungs- oder Regelungseinrichtung die Verstelleinrichtung (27. 28) in Abhängigkeit von dem Sollwert steuert oder regelt.
• Aspekt 5. Verstellventil nach einem der vorhergehenden Aspekte, umfassend
  • eine Regelungseinrichtung für die Regelung eines von der Verdrängerpumpe zu erzeugenden Fluidversorgungsdrucks (P14),
  • eine Sollwertvorgabe für die Vorgabe eines Sollwerts für den Fluidversorgungsdruck (P₁₄), vorzugsweise eines in vorgegebener Weise variablen Sollwerts
  • und einen Sensor für die Ermittlung eines Istwerts des Fluidversorgungsdrucks (P₁₄),
  • wobei die Regelungseinrichtung den Istwert mit dem Sollwert vergleicht und in Abhängigkeit von dem Ergebnis des Vergleichs die Verstelleinrichtung (27, 28) steuert.
• Aspekt 6. Verstellventil nach einer Kombination der zwei vorhergehenden Aspekte, umfassend eine Kontrolleinrichtung, mittels der das Verstellventil (20) von der Steuerung des Fluidversorgungsdrucks (P₁₄) oder Volumenstroms (V₁₄) auf die Regelung des Fluidversorgungsdrucks (P₁₄) oder Volumenstroms (V₁₄) umstellbar ist.
• Aspekt 7. Verstellventil nach einem der vorhergehenden Ansprüche, wobei die Ventilfeder (25) vorgespannt ist und auf den Ventilkolben (22) eine Vorspannkraft ausübt, die größer ist als eine Kraft, die ein bei ordnungsgemäßer Funktion der Verstelleinrichtung (27, 28) größter Ventilstelldruck (P₂₀) auf den Ventilkolben (22) ausübt.
• Aspekt 8. Verstellventil nach einem der vorhergehenden Aspekte, bei dem der Ventilkolben (22) eine weitere Wirkfläche (24) für den Ventilstellruck (P₂₀) aufweist und die Wirkflächen (23, 24) einander entgegen wirkend angeordnet und der Größe nach unterschiedlich sind, um dem Größenunterschied der Wirkflächen (23, 24) entsprechend eine auf den Ventilkolben (22) der Ventilfeder (25) entgegen wirkende Differenzkraft zu erzeugen.
• Aspekt 9. Verstellventil nach dem vorhergehenden Aspekt, bei dem die Wirkflächen (23, 24) einander in Richtung der Beweglichkeit des Ventilkolbens (22) zugewandt den gleichen Fluidraum (26) begrenzen.
• Aspekt 10. Verstellventil nach dem vorhergehenden Aspekt, bei dem der Ventilkolben (22) zwischen einer ersten Position und einer zweiten Position hin und her beweglich ist, in der ersten Position des Ventilkolbens (22) ein Einlass (I) und ein Anschluss (A) für ein den Ventilstelldruck (P₂₀) erzeugendes Druckfluid in den Fluidraum (26) münden und der Ventilkolben (22) in der zweiten Position den Anschluss (A) von dem noch immer in den Fluidraum (26) mündenden Einlass (I) trennt.
• Aspekt 11. Verstellventil nach einem der vorhergehenden Aspekte, bei dem das Ventilgehäuse (21) einen Einlass (I), einen ersten Anschluss (A) und einen zweiten Anschluss (B) für ein Druckfluid aufweist, der Ventilkolben (22) zwischen einer ersten Position und einer zweiten Position hin und her beweglich ist und der Einlass (I) bei in der ersten Position befindlichem Ventilkolben (22) mit dem ersten Anschluss (A) verbunden und von dem zweiten Anschluss (B) getrennt und bei in der zweiten Position befindlichem Ventilkolben (22) mit dem zweiten Anschluss (B) verbunden und von dem ersten Anschluss (A) getrennt ist, um das Druckfluid wahlweise entweder über den ersten Anschluss (A) oder den zweiten Anschluss (B) zu der Pumpe zu leiten.
• Aspekt 12. Verdrängerpumpe mit verstellbarem Fördervolumen, umfassend:
  1. a) ein Pumpengehäuse (1),
  2. b) eine in dem Pumpengehäuse (1) gebildete Förderkammer mit einem Einlass (2) für ein Fluid auf einer Niederdruckseite und einem Auslass (3) für das Fluid auf einer Hochdruckseite der Pumpe,
  3. c) ein in der Förderkammer bewegliches Förderglied (5) für die Förderung des Fluids
  4. d) und ein für die Verstellung des Fördervolumens in einem von dem Förderglied (5) geförderten Strom des Fluids angeordnetes Verstellventil (20) nach einem der vorhergehenden Ansprüche.
• Aspekt 13. Verdrängerpumpe nach dem vorhergehenden Aspekt, wobei
  • zu einer Stirnseite des Förderglieds (5) oder das Förderglied umgebend für die Verstellung des Fördervolumens in dem Pumpengehäuse (1) ein Stellglied (6, 7) bewegbar angeordnet ist,
  • das Stellglied (6, 7) in Richtung seiner Bewegbarkeit mit einer von dem Bedarf eines mit dem Fluid zu versorgenden Aggregats (14) abhängigen Stellkraft beaufschlagbar ist,
  • wobei das Stellglied (6, 7) und das Förderglied (5) Bestandteil einer in dem Pumpengehäuse (1) als Gesamtheit hin und her bewegbaren Verstelleinheit (5, 6, 7) sind oder eines aus Stellglied und Förderglied relativ zu dem anderen und dem Pumpengehäuse verstellbar ist.
• Aspekt 14. Verdrängerpumpe nach dem vorhergehenden Aspekt und wenigstens einem der folgenden Merkmale:
  • die Pumpe ist eine Rotationspumpe, und das Förderglied (5) ist ein in der Förderkammer um eine Drehachse (R₅) drehbar angeordneter Förderrotor;
  • der Stellkraft entgegen wirkend ist eine Pumpenfeder (10) angeordnet.
• Aspekt 15. Verdrängerpumpe nach einem der zwei vorhergehenden Aspekte, wobei das Stellglied (6, 7) mit dem Fluid der Hochdruckseite der Pumpe beaufschlagbar ist, um die Stellkraft zu erzeugen.
• Aspekt 16. Verdrängerpumpe nach dem vorhergehenden Aspekt, wobei das Stellglied (6, 7) einen doppeltwirkenden Stellkolben mit einer ersten Kolbenfläche und einer von der ersten Kolbenfläche abgewandten zweiten Kolbenfläche bildet, die erste Kolbenfläche über einen ersten Anschluss (A) des Verstellventils (20) und die zweite Kolbenfläche über einen zweiten Anschluss (B) des Verstellventils (20) mit einem Druckfluid, vorzugsweise dem Fluid der Hochdruckseite der Pumpe, beaufschlagbar sind und der Ventilkolben (22) zwischen einer ersten Position und einer zweiten Position hin und her bewegbar ist, wobei das Verstellventil (20) in der ersten Position des Ventilkolbens (22) das Druckfluid nur zu der ersten Kolbenfläche und in der zweiten Position nur zu der zweiten Kolbenfläche leitet.
• Aspekt 17. Verdrängerpumpe nach einem der vier vorhergehenden Aspekte und wenigstens einem der folgenden Merkmale:
  • das Stellglied (6, 7) ist gemeinsam mit dem Förderglied (5) oder relativ zu dem Förderglied (5) in Bezug auf die Drehachse (R₅) axial oder quer bewegbar;
  • das Förderglied (5) ist mit einem weiteren Förderglied (4) der Verdrängerpumpe in einem Fördereingriff, um das Fluid zu fördern;
  • die Pumpe ist eine Außenzahnrad- oder Innenzahnradpumpe;
  • das Stellglied (6, 7) weist einen ersten Stellkolben (6) und einen zweiten Stellkolben (7) auf, und das Förderglied (5) ist axial zwischen den Stellkolben (6, 7) angeordnet und mit den Stellkolben (6, 7) als Verstelleinheit (5, 6, 7) im Fördereingriff relativ zu dem weiteren Förderglied (4) axial hin und her bewegbar;
  • die Pumpe ist eine Flügelpumpe, Pendelschieberpumpe oder Innenzahnradpumpe, und das Stellglied ist ein das Förderglied umgebender, quer zu der Drehachse des Förderglieds bewegbarer Stellring.
• Aspekt 18. Verdrängerpumpe nach einem der vorhergehenden Aspekte, wobei das von der Verdrängerpumpe geförderte Fluid auf der Hochdruckseite der Pumpe, vorzugsweise stromabwärts von einer Reinigungseinrichtung (13), abgezweigt und über das Regelventil (20) zurück zu der Pumpe geführt wird, um dort die Stellkraft zu erzeugen.
• Aspekt 19. Verdrängerpumpe nach dem vorhergehenden Aspekt, wobei das zurückgeführte Fluid den Ventilstelldruck (P₂₀) erzeugt, vorzugsweise während des Durchströmens des Verstellventils (20).
• Aspekt 20. Verdrängerpumpe nach einem der vorhergehenden Aspekte, umfassend
  • eine Erfassungseinrichtung für die Erfassung wenigstens einer physikalischen Größe (T, D, L), die den Fluidbedarf eines von der Pumpe zu versorgenden Aggregats (14) kennzeichnet
  • eine Sollwertvorgabe, die in Abhängigkeit von der wenigstens einen erfassten physikalischen Größe (T, D, L) einen Sollwert für einen von der Verdrängerpumpe zu fördernden Volumenstrom (V₁₄) oder zu erzeugenden Fluidversorgungsdruck (P₁₄) bildet,
  • und eine Steuerungs- oder Regelungseinrichtung, die in Abhängigkeit von dem Sollwert die Verstelleinrichtung (27, 28) des Verstellventils (20) steuert oder regelt.
• Aspekt 21. Verdrängerpumpe nach dem vorhergehenden Aspekt, umfassend einen Sensor für die Ermittlung eines Istwerts des Volumenstroms (V₁₄) oder Fluidversorgungsdrucks (P₁₄), wobei die Regelungseinrichtung in Abhängigkeit von einem Vergleich des Sollwerts und des Istwerts eine Stellgröße für die Verstelleinrichtung (27, 28) des Verstellventils (20) bildet.
• Aspekt 22. Verdrängerpumpe nach einem der vorhergehenden Aspekte und wenigstens einem der folgenden Merkmale:
  • die Pumpe wird als Schmierölpumpe in einem Fahrzeug für die Versorgung einer Brennkraftmaschine (14) mit Schmieröl oder eines Automatikgetriebes mit Hydraulikflüssigkeit verwendet,
  • die Pumpe wird von der Brennkraftmaschine (14) angetrieben.

Advantageous features are also described in the subclaims and their combinations as well as in the following aspects.

• Aspect 1. Adjustment valve for the adjustment of the delivery volume of a positive displacement pump, comprising the adjustment valve
  1. a) a valve housing (21),
  2. b) a valve piston (22) movably mounted in the valve housing (21) with an effective surface (23) for a valve actuating pressure (P ₂₀ ) of a fluid,
  3. c) a valve spring (25) which counteracts a force exerted by the valve actuating pressure (P ₂₀ ) on the valve piston (22),
  4. d) and an adjusting device (27, 28) by means of which the valve piston (22) is adjustable in the direction of the force exerted by the valve actuating pressure (P ₂₀ ) or against this force.
• Aspect 2. Adjusting valve according to the preceding aspect and at least one of the following features:
  • the adjusting device (27, 28) is electrically actuated;
  • the adjusting device (27, 28) is formed as a magnetic adjustment device;
  • the adjusting device (27, 28) counteracts the force of the valve spring (25).
• Aspect 3. Adjustment valve according to one of the preceding aspects and at least one of the following features:
  • the adjustment valve (20) is a proportional valve;
  • the adjustment valve (20) is pulse modulated, preferably pulse width modulated, controlled or regulated;
  • the adjustment valve (20) is current controlled or regulated;
  • the adjustment valve (20) is voltage controlled or regulated;
  • the adjustment valve (20) has at least three connections (I, O, A, B), preferably four connections for the fluid;
  • the adjusting valve (20) is switchable between at least two switching positions, preferably three switching positions;
  • the adjustment valve (20) is a directional control valve.
• Aspect 4. An adjustment valve according to one of the preceding aspects, comprising
  • a control or regulation device for the control or regulation of a fluid supply pressure (P ₁₄ ) to be generated by the positive displacement pump or to be conveyed volume flow (V ₁₄ )
  • and a setpoint specification for the specification of at least one pressure or volumetric flow setpoint value, preferably of a setpoint value variable in a predefined manner,
  • wherein the control or regulating device controls or regulates the adjusting device (27, 28) as a function of the desired value.
• Aspect 5. An adjustment valve according to one of the preceding aspects, comprising
  • a control device for controlling a fluid supply pressure to be generated by the positive displacement pump (P14),
  • a setpoint specification for the specification of a setpoint value for the fluid supply pressure (P ₁₄ ), preferably of a setpoint value variable in a predefined manner
  • and a sensor for determining an actual value of the fluid supply pressure (P ₁₄ ),
  • wherein the control device compares the actual value with the desired value and controls the adjusting device (27, 28) as a function of the result of the comparison.
• Aspect 6. Adjustment valve according to a combination of the two preceding aspects, comprising a control device, by means of which the adjustment valve (20) is controlled from the control of the fluid supply pressure (P ₁₄ ) or volumetric flow (V ₁₄ ) to the regulation of the fluid supply pressure (P ₁₄ ) or volumetric flow ( V ₁₄ ) is adjustable.
• Aspect 7. Adjustment valve according to one of the preceding claims, wherein the valve spring (25) is biased and on the valve piston (22) exerts a biasing force which is greater than a force which, with proper functioning of the adjusting device (27, 28) largest valve actuating pressure (P ₂₀ ) on the valve piston (22) exerts.
• Aspect 8. Adjustment valve according to one of the preceding aspects, in which the valve piston (22) has a further active surface (24) for the valve actuating pressure (P ₂₀ ) and the active surfaces (23, 24) are arranged counter to each other and are different in size, in order to produce the difference in size of the active surfaces (23, 24) corresponding to a force acting on the valve piston (22) of the valve spring (25) counteracting differential force.
• Aspect 9. Adjustment valve according to the preceding aspect, wherein the active surfaces (23, 24) facing each other in the direction of movement of the valve piston (22) define the same fluid space (26).
• Aspect 10. An adjustment valve according to the preceding aspect, wherein the valve piston (22) is reciprocable between a first position and a second position, in the first position of the valve piston (22) an inlet (I) and a port (A) for a valve actuating pressure (P ₂₀ ) generating pressure fluid into the fluid chamber (26) open and the valve piston (22) in the second position the port (A) of the still in the fluid space (26) opening inlet (I) separates.
• Aspect 11. An adjustment valve according to any one of the preceding aspects, wherein the valve housing (21) has an inlet (I), a first port (A) and a second port Comprising a pressurized fluid port (B) which is reciprocable between a first position and a second position and the inlet (I) with the first piston (22) in the first position with the first port (A) connected and disconnected from the second port (B) and connected to the second port (B) in the second position (22) and disconnected from the first port (A) to selectively dispense the pressurized fluid either via the first port (B). A) or the second port (B) to the pump.
• Aspect 12. Displacement pump with adjustable delivery volume, comprising:
  1. a) a pump housing (1),
  2. b) a delivery chamber formed in the pump housing (1) having an inlet (2) for a fluid on a low pressure side and an outlet (3) for the fluid on a high pressure side of the pump,
  3. c) a movable in the delivery chamber conveying member (5) for the delivery of the fluid
  4. d) and an adjustment valve (20) according to any one of the preceding claims for the adjustment of the delivery volume in a flow of the fluid conveyed by the delivery member (5).
• Aspect 13. Positive displacement pump according to the preceding aspect, wherein
  • to an end face of the conveying member (5) or surrounding the conveying member for the adjustment of the delivery volume in the pump housing (1) an actuator (6, 7) is movably arranged,
  • the actuator (6, 7) can be acted upon in the direction of its mobility by a force dependent on the requirement of an aggregate (14) to be supplied with the fluid,
  • wherein the actuator (6, 7) and the delivery member (5) are part of an adjustment unit (5, 6, 7) reciprocally movable in the pump housing (1) or one of the actuator and delivery member relative to the other and the pump housing is adjustable.
• Aspect 14. A positive displacement pump according to the preceding aspect and at least one of the following features:
  • the pump is a rotary pump, and the conveying member (5) is a conveying rotor rotatably arranged in the conveying chamber about a rotation axis (R ₅ );
  • the actuating force counteracting a pump spring (10) is arranged.
• Aspect 15. Positive displacement pump according to one of the two preceding aspects, wherein the actuator (6, 7) is acted upon by the fluid of the high pressure side of the pump to generate the actuating force.
• Aspect 16. Positive displacement pump according to the preceding aspect, wherein the actuator (6, 7) forms a double-acting actuating piston with a first piston surface and a second piston surface facing away from the first piston surface, the first piston surface via a first connection (A) of the adjustment valve (20). and the second piston surface can be acted upon by a pressure fluid, preferably the fluid of the high-pressure side of the pump, via a second connection (B) of the adjustment valve (20) and the valve piston (22) can be moved back and forth between a first position and a second position, wherein the adjustment valve (20) in the first position of the valve piston (22) directs the pressure fluid only to the first piston surface and in the second position only to the second piston surface.
• Aspect 17. Positive displacement pump according to one of the four preceding aspects and at least one of the following features:
  • the actuator (6, 7) is axially or transversely movable with the conveyor member (5) or relative to the conveyor member (5) with respect to the axis of rotation (R ₅ );
  • the delivery member (5) is in conveying engagement with another delivery member (4) of the positive displacement pump to deliver the fluid;
  • the pump is an external gear or internal gear pump;
  • the actuator (6, 7) has a first actuating piston (6) and a second actuating piston (7), and the conveying member (5) is arranged axially between the actuating piston (6, 7) and with the actuating piston (6, 7) as Adjusting unit (5, 6, 7) in the conveying engagement relative to the further conveying member (4) axially reciprocally movable;
  • the pump is a vane pump, pendulum vane pump or internal gear pump, and the actuator is a collar surrounding the conveyor member and movable relative to the axis of rotation of the conveyor member.
• Aspect 18. Positive displacement pump according to one of the preceding aspects, wherein the pumped by the positive displacement pump fluid on the high pressure side of the pump, preferably downstream of a cleaning device (13), branched and fed via the control valve (20) back to the pump to there Force to generate.
• Aspect 19. Positive displacement pump according to the preceding aspect, wherein the recirculated fluid generates the valve set pressure (P ₂₀ ), preferably during the flow through the adjustment valve (20).
• Aspect 20. A positive displacement pump according to any preceding aspect, comprising
  • a detection device for the detection of at least one physical quantity (T, D, L), which characterizes the fluid requirement of an aggregate (14) to be supplied by the pump
  • a desired value input which, as a function of the at least one detected physical variable (T, D, L), forms a desired value for a volume flow (V ₁₄ ) to be delivered by the positive displacement pump or fluid supply pressure (P ₁₄ ) to be generated,
  • and a control or regulating device which controls or regulates the adjusting device (27, 28) of the adjusting valve (20) as a function of the desired value.
• Aspect 21. Displacement pump according to the preceding aspect, comprising a sensor for determining an actual value of the volume flow (V ₁₄ ) or fluid supply pressure (P ₁₄ ), wherein the control device in response to a comparison of the setpoint and the actual value, a manipulated variable for the adjusting device (27 , 28) of the adjusting valve (20).
• Aspect 22. Positive displacement pump according to one of the preceding aspects and at least one of the following features:
  • the pump is used as a lubricating oil pump in a vehicle for supplying an internal combustion engine (14) with lubricating oil or an automatic transmission with hydraulic fluid,
  • the pump is driven by the internal combustion engine (14).

Figur 1

eine Verdrängerpumpe in einem Querschnitt,

Figur 2

die Verdrängerpumpe in einem Längsschnitt,

Figur 3

die Verdrängerpumpe mit einem Verstellventil für die Verstellung des Fördervolumens der Pumpe,

Figur 4

das Verstellventil einzeln als Schaltzeichen und

Figur 5

das Verstellventil 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 form the subject matter of the claims and also the embodiments described above. Show it:

FIG. 1

a positive displacement pump in a cross section,

FIG. 2

the positive displacement pump in a longitudinal section,

FIG. 3

the displacement pump with an adjustment valve for the adjustment of the delivery volume of the pump,

FIG. 4

the adjusting valve individually as a symbol and

FIG. 5

the adjustment valve in a longitudinal section.

FIG. 1 shows a positive displacement pump in a cross section. In a pump housing 1, a delivery chamber having an inlet 2 on a low pressure side and an outlet 3 on a high pressure side is formed. In the delivery chamber, a first delivery member 4 and a second delivery member 5 are movably arranged. The conveying members 4 and 5 are in a conveying engagement with each other. If the conveying members 4 and 5 are driven, they perform a conveying movement in the conveying engagement, through which a fluid, for example lubricating oil or a hydraulic fluid, is sucked through the inlet 2 into the conveying chamber and displaced with higher pressure through the outlet 3. The conveyor member 4 is driven and drives the conveyor member 5 in the conveying engagement.

The positive displacement pump of the embodiment is an external gear pump. The conveyor members 4 and 5 are accordingly externally circumferentially toothed conveyor rotors and the conveying engagement a tooth engagement. The conveying members 4 and 5 are rotatably mounted about a respective axis of rotation R ₄ and R ₅ . In a rotary drive, the sucked fluid from the inlet 2 is transported in each of the conveyor members 4 and 5 formed by the tooth gaps conveyor cells through the region of the so-called loop 1a and ejected through the outlet 3.

In order to adapt the volume of the pump to the needs of a to be supplied with the fluid aggregate along the axes of rotation is R ₄ and R ₅ measured axial length of the conveying engagement of the conveying members 4 and 5, the engagement length, adjustable. For the adjustment, the conveying member 5 is relative to the conveying member 4 and the pump housing 1 axially between a position of maximum engagement length and, accordingly, maximum Delivery volume and a position of minimum engagement length and correspondingly minimal delivery volume back and forth movable.

FIG. 2 shows the positive displacement pump in a longitudinal section. The conveyor member 4 is secured against rotation on a drive shaft which protrudes from the pump housing 1 and carries a drive wheel for driving the pump. The conveying member 5 is part of an adjusting unit, which comprises an actuator with two adjusting pistons 6 and 7 via the conveying member 5 addition. This adjusting unit 5-7 is as a whole in the pump housing 1 axially movable back and forth to adjust the engagement length can. The conveying member 5 is arranged axially between the adjusting pistons 6 and 7. The actuator 6, 7 supports the conveyor member ₅ rotatable about the axis of rotation R ₅ . The adjusting unit 5-7 is accommodated in a cylindrical cavity of the pump housing 1. The cavity forms an axial track for the movements of the adjustment 5-7. Furthermore, it forms on one axial side of the adjusting 5-7 a pressure chamber 8 and on the other side a further pressure chamber 9. The control pistons 6 and 7 separate the two pressure chambers 8 and 9 of unavoidable leakage fluidly apart from each other and also from the delivery chamber. The pressure chambers 8 and 9 are each printable with a pressurized fluid, in the embodiment with the funded by the positive displacement pump fluid. In the pressure chamber 9, a pump spring 10 is arranged, whose spring force acts on the adjusting unit 5-7, namely on the actuating piston 7, in the direction of maximum engagement length.

FIG. 3 shows the positive displacement pump integrated into a closed fluid circuit, for example, a lubricating oil circuit of a motor vehicle. The fluid circuit includes a reservoir 11, from which the pump sucks the fluid on the low pressure side through the inlet 2 and higher pressure on the high pressure side through the outlet 3, a connected supply line 12 and a cooling and cleaning device 13 with a radiator and a Filter to the supplied with the fluid unit 14, for example, an internal combustion engine for driving a motor vehicle, promotes. Downstream of the unit 14, the fluid is passed through a conduit 15 back into the reservoir 11.

Downstream of the cooling and cleaning device 13, in particular downstream of the cleaning part of the cooling and cleaning device 13, but still upstream of the unit 14, a partial flow 16 of the fluid is diverted and returned via an adjustment valve 20 to the pump. The adjustment valve 20 has an inlet for the partial flow 16, one with the reservoir 11 shorted outlet and two other ports, one of which is connected via a line 18 to the pressure chamber 8 and the other via a line 19 to the pressure chamber 9. The adjustment valve 20 is a multi-way switching valve. In a first switching position, it carries the partial flow 16 into the pressure chamber 8 and connects the pressure chamber 9 with the reservoir 11, thus switching the pressure chamber 9 to ambient pressure. In a second switching position, the adjusting valve in FIG. 3 It reverses these conditions by the partial flow 16 leads into the pressure chamber 9 and the pressure chamber 8 short-circuits with the reservoir 11. The adjustment valve 20 of the embodiment can assume three switching positions. namely, the two mentioned switching positions and also a center position in which it separates the pressure chambers 8 and 9 from each other and also from the reservoir 11 and the partial flow 16, so that the respective pressure in the pressure chambers 8 and 9 is maintained, you can see of leaks and associated leakage. In the exemplary embodiment, a 4/3-way valve was selected for the adjustment valve 20.

FIG. 4 shows the adjustment valve 20 as in FIG. 3 as a switching symbol, only in an enlarged view. Entered are the four ports of the adjusting valve 20, of which the inlet for the recirculated partial flow 16 with I, the outlet to the reservoir 11 with O, the connection for the pressure chamber 8 with A and the connection for the pressure chamber 9 with B are designated.

The adjustment valve 20 is a proportional valve with a constantly acting fluidic valve set pressure P20, namely the pressure of the recirculated fluid in the partial flow 16, and a valve spring 25, which is the valve actuating pressure P ₂₀ counteracting arranged. However, the fluidic valve actuating pressure P ₂₀ and the force of the valve spring 25 alone do not determine its switching position when the adjustment valve ₂₀ functions properly. The adjustment valve 20 comprises as a proportional valve an adjusting device, which adjusts the adjustment valve 20 adapted to the fluid requirement of the unit 14 from one of the switching positions to another. The valve actuating pressure P ₂₀ and the valve spring 25 give the adjusting valve 20 a fail-safe property in the event of failure of the proportional adjusting device.

The adjusting device is a magnetic adjustment device, which is connected with a pulse-width-modulated electrical control signal. The control signal is from a control device in the form of a rectangular signal with a constant upper and a constant lower signal level, such as voltage level, and a generated specific period t. According to the pulse width modulation, the time duration of the upper signal level, the so-called switch-on time, and subsequently the duration of the lower signal level, the switch-off time, can be varied accordingly. The magnetic force of the adjusting device changes according to the duty cycle of the actuating signal, ie the ratio of the switch-on time to the period t. The switching position of the adjusting valve 20 results from the equilibrium of forces of the force of the valve spring 25 and the two counteracting forces, namely the fluidic force generated by the valve actuating pressure P ₂₀ and the magnetic force. The larger the valve actuating pressure P ₂₀ , the smaller is the magnetic force corresponding to the balance of the forces. If the sum of fluidic force and magnetic force exceeds the spring force, the valve piston 22 moves in the direction of the first switching position, and the delivery volume of the positive displacement pump is stopped. If the force of the valve spring 25 predominates, the valve piston 22 moves to the second switching position, and the displacement unit 5-7 moves accordingly in the direction of maximum delivery volume.

In a modification, the switch-on time and the switch-off time are assigned to the first and the second switch position of the adjustment valve 20. With proper functioning of the adjusting device, the position of the valve piston 22 and, associated therewith, the switching position of the adjusting valve _{20 are} decoupled from the valve actuating pressure P ₂₀ . By way of example, let it be assumed that the adjusting valve 20 assumes the first switching position during each switch-on time, in which the fluid of the partial flow 16 is returned to the pressure chamber 8, and during each switch-off time assumes the second switch position, in which the fluid is returned to the pressure chamber 9.

By varying the switch-on time and corresponding to the switch-off time, the flow through the adjustment valve 20 to the respective pressure chamber 8 or 9 can be varied practically continuously in both embodiments because of the significantly shorter period duration t of the actuating signal compared to the relevant time constant of the pump. Accordingly, the pressure in the pressure 8 and the pressure in the pressure chamber 9 can be changed continuously.

As a result, the adjusting unit can be moved 5-7 along its axial displacement in any axial position and held there. The delivery volume is thus flexibly and precisely continuously adapted to the fluid requirement of the unit 14 between the maximum and the minimum delivery volume.

For the needs-based supply of the unit 14 is stored in a control of the unit 14, in the embodiment of a motor controller, a map in an electronic or optical memory. The map contains for the relevant with regard to the fluid requirements operating conditions of the unit 14 each have a predetermined setpoint for the fluid supply pressure P ₁₄ or the flow rate V ₁₄ , which requires the unit 14 in the respective operating state. These volume flow or pressure setpoints are stored in the map in dependence on physical quantities that characterize the operating conditions to be distinguished with regard to the fluid requirement. Examples of the physical variables are the temperature T, the speed D and the load L called. The unit 14 has a detection device for detecting one or more of the different operating conditions characteristic physical quantity (s). The temperature T can be measured, for example, at a critical point of the unit 14, in a cooling fluid serving to cool the unit 14, or in the fluid delivered by the pump 3. The speed D can be detected very easily by means of a tachometer and the load L on the accelerator pedal or a throttle position. Depending on the detected variables selects a setpoint input based on the map of the associated pressure or flow setpoint and outputs it to the control device for the adjustment valve 20. The control device forms the actuating signal, namely the ratio of the switch-on time to the period t, in accordance with the current setpoint value. A feedback by means of a control variable, in this case a measured actual value of the fluid supply pressure P ₁₄ or the volume flow V ₁₄ , is not required, as long as the actual fluid requirement of the unit 14 corresponds to the desired value.

The control on the basis of the desired value can in particular be supplemented by a current control. The current control is used in particular to compensate for changes in resistance of the magnetic adjustment device, as they can take place especially in temperature changes. In this case, the current consumption of the adjusting device is detected by a detection device and kept at a specific current value. If, by means of the detection device, a change in the current consumption and accordingly of the electrical resistance of the adjusting device is detected, the duty cycle is changed in such a way that the current consumption again corresponds to the current value before the resistance change.

In the event that the actual fluid requirement of the unit 14 changes and deviates from the desired values of the characteristic field, for example because of wear occurring during the life of the unit 14, a regulating device is also provided for the adjustment valve 20. The control device forms the control signal for the adjustment valve 20 as a function of a desired-actual comparison on the basis of a required for the unit 14 fluid supply pressure P ₁₄ or flow V ₁₄ . The control device has access to a memory in which other setpoint values of the pressure P ₁₄ or volumetric flow V ₁₄ are stored in the form of a characteristic map comparable to the characteristic map previously used for the control. The maps of the pressure setpoints or volume flow setpoints can be stored in physically different memories or in the same memory in different areas. Furthermore, a higher-level control device is provided, which may be part of the pressure or volume flow control device or the control device and switches from the controller to a control, if it is determined that the demand of the unit has changed so much that the map of the setpoints does not adequately describe actual demand because demand has increased, for example due to wear. For the desired-actual pressure comparison, the actual prevailing fluid supply pressure P ₁₄ can be detected, for example, at the most downstream point of consumption of the unit 14 or in the example of the internal combustion engine at the motor gallery and compared with the relevant for the respective operating pressure target value, for example by subtraction of target and actual value.

The example described as non-feedback pressure or flow control can be further developed to a pressure or flow control with a target / actual comparison of the respective pressure or flow rate setpoint with an actual value to be measured for the comparison. Several maps for the volume flow V ₁₄ or fluid supply pressure P ₁₄ can be stored in advance, which describe the need for different times in the life cycle of the unit 14, for example, a map for the first n kilometers of a motor vehicle or n operating hours of the unit 14, the next m mileage of the vehicle or m operating hours of the unit etc. On the basis of, for example, the mileage of the vehicle or an operating time detection can be converted in such embodiments of the first used map to the next, etc. Finally, the control device may also have the ability to change the setpoint values of the characteristic map in accordance with the state of the unit 14 in order to better adjust the adjustment valve 20 on the basis of the changed characteristic field to be able to control adapted to the respective state of the unit 14. The change in the desired values of the characteristic map or the selection of one of several predetermined maps is advantageously carried out automatically, for example on the basis of the already mentioned mileage or the operating time or a detection of the fluid supply pressure P ₁₄ and comparison with or predetermined in the form of a map pressure setpoint (s Although such a target / actual comparison could be used for a pressure control of the adjustment valve 20, but preferably only for the selection of the pressure or volume flow map to be used or the change in the pressure or flow rate setpoints of a single predetermined map is used for control.

In the Figures 3 and 4 is for the generation of the valve actuating pressure P ₂₀ of the recirculated partial flow 16 again diverted a partial flow 17 in front of the adjusting valve 20 and thus a valve piston of the adjusting valve 20 of the valve spring 25 counteracted.

FIG. 5 shows in a longitudinal section a modified with respect to the generation of the valve actuating pressure P ₂₀ adjustment valve 20. The valve actuating pressure P ₂₀ is different than in the adjustment of the FIG. 4 not by means of an additional partial flow in the Figures 3 and 4 the partial flow 17, but by means of to be controlled or regulated flow of the partial flow 16. Apart from this modification apply to the adjustment valve 20 of the Figures 3 and 4 made statements for the modified adjustment valve 20 and the comments made for this also for the adjustment valve 20 of the Figures 3 and 4 ,

The adjustment valve 20 has a valve housing 21 and a valve piston 22 axially movable in the valve housing 21 along a central valve axis S back and forth. From the adjusting device, a magnetic coil 27 and an anchor formed of soft iron 28 are shown. The solenoid coil 27 is fixedly connected to the valve housing 21 and surrounds the armature 28. The armature 28 is connected to the valve piston 22 axially immovable, so that the valve piston 22 and the armature 28 axial movements such as to execute a unit.

The valve piston 22 has a first active surface 23 and a second active surface 24 for the valve actuating pressure P ₂₀ . The active surfaces 23 and 24 define axially together a fluid space 26 and are facing each other axially. The effective surface 23, to which the Valve set pressure P _{20 of} the valve spring 25 counteracts, is greater than the effective area 24, wherein in FIG. 5 the circumstances are exaggerated. In fact, the difference in size is only slightly, but defined so that the valve actuating pressure P ₂₀ always exerts on the valve piston 22 a differential force corresponding to the size difference of the active surfaces 23 and 24, which counteracts the force of the valve spring 25. Since the valve piston 22 can be made very accurate to the size difference of the active surfaces 23 and 24, and the differential force correspondingly small and the valve spring 25 advantageously softer than in the embodiment of FIG. 4 be. Correspondingly low forces required the adjusting device 27, 28. The adjustment valve 20 is more sensitive overall, and it can be the switching times of the adjustment valve 20 is shortened.

The inlet I for the fluid to be controlled or opens in all switching positions of the adjusting valve 20 in the fluid chamber 26. In the illustrated switching position, the switching position of the adjusting valve 4 in the Figures 3 and 4 corresponds, the port B opens into the fluid chamber 26, and the valve piston 22 separates the fluid chamber 26 and thus the inlet I of the other terminal A. Accordingly, the fluid of the partial flow 16 is returned to the pressure chamber 9, while the pressure chamber 8 via the port A connected to the reservoir 11 and thus connected without pressure. In this switching position, the connection A is connected to the outlet O via a space of the valve housing 21, in which the valve spring 25 is arranged, and to the reservoir 11 via this. If the control signal changes its signal level, in the exemplary embodiment from the lower to the upper signal level, the magnetic coil 27 is energized and shifts the armature 28 against the force of the valve spring 25 in the axial direction first in the middle switching position and with a correspondingly long switch-on until the other extreme switching position , the first switch position. In the middle switching position, the valve piston 22 separates both ports A and B from the fluid chamber 26 into which the inlet I still opens. In the first switching position, the valve piston 22 assumes such an axial position that the fluid space 26 is in axial overlap with both the inlet I and the port A, while the valve piston 22 in the respective axial position the port B of the fluid space 26th fluidly separates. In the first switching position, the fluid of the partial flow 16 is passed through the fluid space 26 and the port A in the pressure chamber 8, while the pressure chamber 9 via the port B and a passage C of the valve piston 22 to the outlet O and finally connected to the reservoir 11 is.

The valve piston 22 is hollow. The passage C is formed in a cylindrical jacket region of the valve piston 22, which adjoins the active surface 24 in the direction of the armature 28 and forms a narrow sealing gap with the surrounding jacket of the valve housing 21, which fluidically displaces the adjusting device 27, 28 from the fluid space 26 separates. A cylindrical jacket region of the valve piston 22, which forms a further narrow sealing gap with the valve housing 21, radially adjoins the active surface 23 and away from the adjusting device 27, 28, as long as the adjusting valve 20 does not assume the first switching position in which the valve piston 22 occupies the axial position in which the fluid space 26 is in axial overlap with the port A.

The adjusting device 27, 28 with the associated control device switches the adjustment valve 20 over the entire operating range of the unit 14 and controls or regulates the axial position of the adjustment 5-7 and consequently the delivery volume of the positive displacement pump over the entire volume flow range, for the adapted supply of the unit 14 is required. The fluidic valve set pressure P ₂₀ and the valve spring 25 serve as backup application in the event that the adjusting device 27, 28 or the associated control device fails due to a defect, for example due to a broken cable or a loose electrical connector. The adjustment valve 20 is designed so that in the event of failure, the delivery volume of the pump from maximum towards minimum is adjusted only upon reaching a fluid supply pressure P ₁₄ , which is greater than a maximum fluid supply pressure P ₁₄ , which is established with proper function of the adjustment valve 20 , For this purpose, the valve spring 25 is installed with a biasing force which is greater than a force which exerts a maximum Ventilstelldruck P ₂₀ , which can be set with proper function, on the valve piston 22.

Reference numerals:

1

pump housing

1a

wrap

2

inlet

3

outlet

4

conveying member

5

conveying member

6

actuating piston

7

actuating piston

8th

pressure chamber

9

pressure chamber

10

pump spring

11

reservoir

12

management

13

Cooling and cleaning device

14

aggregate

15

management

16

partial flow

17

partial flow

18

management

19

management

20

adjusting valve

21

valve housing

22

plunger

23

effective area

24

effective area

25

valve spring

26

fluid space

27

solenoid

28

anchor

A

connection

B

connection

I

inlet

O

outlet

S

valve axis

t

period

D

rotation speed

L

load

T

temperature

P ₁₄

Fluid supply pressure

V ₁₄

flow

Claims (19)

Displacement pump with adjustable delivery volume, 1.1 which is installed in a motor vehicle and preferably also the positive displacement pump or is provided for installation in order to supply an internal combustion engine driving the motor vehicle with lubricating oil, the positive displacement pump comprising: 1.2 a pump housing (1), 1.3 a delivery chamber formed in the pump housing (1) having an inlet (2) for a fluid on a low-pressure side and an outlet (3) for the fluid on a high-pressure side of the pump, 1.4 a movable in the delivery chamber conveying member (5) for the delivery of the fluid 1.5 and an adjustment valve (20) arranged for the adjustment of the delivery volume in a flow of the fluid delivered by the delivery member (5), comprising: 1.5.1 a valve housing (21), 1.5.2 a in the valve housing (21) movably mounted valve piston (22) having an effective surface (23) for a valve actuating pressure (P ₂₀ ) of a fluid, 1.5.3 a valve spring (25) which counteracts a force exerted by the valve actuating pressure (P ₂₀ ) on the valve piston (22), 1.5.4 and an adjusting device (27, 28) by means of which the valve piston (22) is adjustable in the direction of the force exerted by the valve actuating pressure (P ₂₀ ) or against this force, 1.5.5 wherein the valve piston (22) has a further active surface (24) for the valve actuating pressure (P ₂₀ ) and the active surfaces (23, 24) arranged counter to each other and are different in size to the size difference of the active surfaces (23, 24) according to a on the valve piston (22) of the valve spring (25) counteracting differential force to produce. Positive displacement pump according to the preceding claim, wherein the active surfaces (23, 24) facing each other in the direction of the mobility of the valve piston (22) define the same fluid space (26). A positive displacement pump as claimed in the preceding claim, wherein the valve piston (22) is reciprocable between a first position and a second position, an inlet (I) and a port (A) for the first position of the valve piston (22) Valve set pressure (P ₂₀ ) generating pressure fluid into the fluid chamber (26) open and the valve piston (22) in the second position the port (A) of the still in the fluid space (26) opening inlet (I) separates. A positive displacement pump as claimed in any preceding claim, wherein the valve housing (21) has an inlet (I), a first port (A) and a second port (B) for a pressurized fluid, the valve piston (22) between a first position and a second port Position is reciprocally movable and the inlet (I) in the first position befindlichem valve piston (22) connected to the first port (A) and separated from the second port (B) and in the second position befindlichem valve piston (22) connected to the second port (B) and separated from the first port (A) to selectively direct the pressurized fluid to the pump via either the first port (A) or the second port (B). Positive displacement pump according to one of the preceding claims and at least one of the following features: - The adjusting device (27, 28) is electrically actuated; - The adjusting device (27, 28) is formed as a magnetic adjustment device; - The adjusting device (27, 28) counteracts the force of the valve spring (25). Positive displacement pump according to one of the preceding claims and at least one of the following features: - The adjustment valve (20) is a proportional valve; - The adjustment valve (20) is pulse modulated, preferably pulse width modulated, controlled or regulated; - The adjustment valve (20) is current controlled or -geregelt; - The adjustment valve (20) is voltage controlled or -geregelt; - The adjustment valve (20) has at least three ports (I, O, A, B), preferably four ports for the fluid; - The adjustment valve (20) is switchable between at least two switching positions, preferably three switching positions; - The adjustment valve (20) is a directional control valve. Positive displacement pump according to one of the preceding claims, comprising a control or regulation device for the control or regulation of a fluid supply pressure (P ₁₄ ) to be generated by the displacement pump or a volume flow (V ₁₄ ) to be delivered and a nominal value specification for specifying at least one pressure or volumetric flow nominal value, preferably a nominally variable nominal value, - Wherein the control or regulating device controls the adjusting device (27. 28) in response to the desired value or regulates. Positive displacement pump according to one of the preceding claims, comprising a control device for the regulation of a fluid supply pressure (P14) to be generated by the positive displacement pump, - a setpoint input for providing a setpoint for the fluid supply pressure (P _14), preferably of a variable in a predetermined manner setpoint and a sensor for determining an actual value of the fluid supply pressure (P ₁₄ ), - wherein the control device compares the actual value with the desired value and controls the adjusting device (27, 28) as a function of the result of the comparison. Positive displacement pump according to a combination of the two preceding claims, comprising a control device, by means of which the adjustment valve (20) from the control of the fluid supply pressure (P ₁₄ ) or volume flow (V ₁₄ ) to the regulation of the fluid supply pressure (P ₁₄ ) or volume flow (V ₁₄ ) is convertible. Positive displacement pump according to one of the preceding claims, wherein the valve spring (25) is biased and exerts on the valve piston (22) a biasing force which is greater than a force which, with proper functioning of the adjusting device (27, 28) largest valve actuating pressure (P _20th ) exerts on the valve piston (22). Positive displacement pump according to one of the preceding claims, wherein - To an end face of the conveying member (5) or the conveying member surrounding an adjusting member (6, 7) is movably arranged for the adjustment of the delivery volume in the pump housing (1), - The actuator (6, 7) is acted upon in the direction of its mobility with a dependent of the need for a fluid to be supplied to the unit (14) actuating force, - wherein the actuator (6, 7) and the conveying member (5) are part of a in the pump housing (1) as a whole back and forth movable adjusting unit (5, 6, 7) or one of actuator and conveying member relative to the other and the Pump housing is adjustable. Positive displacement pump according to the preceding claim and at least one of the following features: - The pump is a rotary pump, and the conveying member (5) is in the conveying chamber about a rotational axis (R ₅ ) rotatably arranged conveying rotor; - The actuating force counteracting a pump spring (10) is arranged. Positive displacement pump according to one of the two preceding claims, wherein the actuator (6, 7) is acted upon by the fluid of the high pressure side of the pump to generate the actuating force. Positive displacement pump according to the preceding claim, wherein the actuator (6, 7) forms a double-acting actuator piston with a first piston surface and a second piston surface facing away from the first piston surface, the first piston surface via a first port (A) of the adjustment valve (20) and the second Piston surface via a second port (B) of the adjusting valve (20) with a pressurized fluid, preferably the fluid of the high pressure side of the pump, are acted upon and the valve piston (22) between a first position and a second position reciprocally movable, wherein the adjusting valve (20) in the first position of the valve piston (22) directs the pressurized fluid only to the first piston surface and in the second position only to the second piston surface. Positive displacement pump according to one of the four preceding claims and at least one of the following features: - The actuator (6, 7) is movable together with the conveying member (5) or relative to the conveying member (5) with respect to the axis of rotation (R ₅ ) axially or transversely; - The conveying member (5) is in a conveying engagement with a further conveying member (4) of the positive displacement pump, in order to convey the fluid; - The pump is an external gear or internal gear pump; - The actuator (6, 7) has a first actuating piston (6) and a second actuating piston (7), and the conveying member (5) is arranged axially between the adjusting piston (6, 7) and with the adjusting piston (6, 7) as adjusting unit (5, 6, 7) in the conveying engagement relative to the further conveying member (4) axially reciprocally movable; - The pump is a vane pump, pendulum slide pump or internal gear pump, and the actuator is a surrounding the conveyor member, movable transversely to the axis of rotation of the conveyor member adjustable collar. Positive displacement pump according to one of the preceding claims, wherein the pumped by the positive displacement pumping fluid on the high pressure side of the pump, preferably downstream of a cleaning device (13), and fed via the control valve (20) back to the pump to generate the actuating force there , Positive displacement pump according to the preceding claim, wherein the recirculated fluid generates the valve set pressure (P ₂₀ ), preferably during the flow through the adjusting valve (20). Positive displacement pump according to one of the preceding claims, comprising - A detection device for the detection of at least one physical quantity (T, D, L), which identifies the fluid requirement of a to be supplied by the pump unit (14) a nominal value specification which, as a function of the at least one detected physical variable (T, D, L), forms a desired value for a volume flow (V ₁₄ ) to be delivered by the positive displacement pump or fluid supply pressure (P ₁₄ ) to be generated, - And a control or regulating device which controls or regulates the adjusting device (27, 28) of the adjusting valve (20) in dependence on the desired value. Positive displacement pump according to the preceding claim, comprising a sensor for determining an actual value of the volume flow (V ₁₄ ) or fluid supply pressure (P ₁₄ ), wherein the regulating device in dependence on a comparison of the desired value and the actual value a manipulated variable for the adjusting device (27, 28) the adjusting valve (20) forms.

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