EP0225338B1 - Variable capacity pump - Google Patents

Variable capacity pump Download PDF

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Publication number
EP0225338B1
EP0225338B1 EP86902794A EP86902794A EP0225338B1 EP 0225338 B1 EP0225338 B1 EP 0225338B1 EP 86902794 A EP86902794 A EP 86902794A EP 86902794 A EP86902794 A EP 86902794A EP 0225338 B1 EP0225338 B1 EP 0225338B1
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EP
European Patent Office
Prior art keywords
pressure
lubricating
pump
outlet
channel
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP86902794A
Other languages
German (de)
French (fr)
Other versions
EP0225338A1 (en
Inventor
Siegfried Hertell
Dieter Otto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Oerlikon Barmag AG
Original Assignee
Barmag AG
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Filing date
Publication date
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Publication of EP0225338A1 publication Critical patent/EP0225338A1/en
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Publication of EP0225338B1 publication Critical patent/EP0225338B1/en
Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
    • F04C15/06—Arrangements for admission or discharge of the working fluid, e.g. constructional features of the inlet or outlet
    • F04C15/064—Arrangements for admission or discharge of the working fluid, e.g. constructional features of the inlet or outlet with inlet and outlet valves specially adapted for rotary or oscillating piston machines or pumps
    • F04C15/066—Arrangements for admission or discharge of the working fluid, e.g. constructional features of the inlet or outlet with inlet and outlet valves specially adapted for rotary or oscillating piston machines or pumps of the non-return type
    • F04C15/068—Arrangements for admission or discharge of the working fluid, e.g. constructional features of the inlet or outlet with inlet and outlet valves specially adapted for rotary or oscillating piston machines or pumps of the non-return type of the elastic type, e.g. reed valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C14/00—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations
    • F04C14/24—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C14/00—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations
    • F04C14/24—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves
    • F04C14/26—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves using bypass channels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2/00—Rotary-piston machines or pumps
    • F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C2/082—Details specially related to intermeshing engagement type machines or pumps
    • F04C2/084—Toothed wheels

Definitions

  • the invention relates to an internal combustion engine, the lubricating oil pump of which is a control pump for hydraulic fluid, the flow rate of which is speed-dependent up to a limit value and, moreover, remains essentially constant regardless of the speed.
  • a piston machine is known from DE-OS-2 758 376, the oil pump of which is an internal rotor gear pump. With this pump, the teeth are designed so that a degree of coverage of 1 is aimed for.
  • An internal combustion engine is also required to have a long service life without expert maintenance. This is opposed to the fact that the internal combustion engine is subject to wear, which leads to an increase in lubricating oil consumption and to a drop in pressure in the lubricating oil system.
  • the lubricating oil pump must therefore also be adapted to this increasing demand in the course of the service life. This leads to the fact that this delivery portion of the lubricating oil pump, which is not required, leads to corresponding energy losses.
  • the object of the invention is to provide a lubricating oil system for an internal combustion engine, in which, on the one hand, the lubricating oil pump supplies a sufficient amount of lubricating oil in all operating states, on the other hand, however, unnecessary, lossy delivery is avoided.
  • the toothing is carried out so that the tooth flanks of the teeth, which lie between the intersections of the tip circles, are in engagement with one another and therefore form individual cells in their tooth gaps, which are closed off from one another in the circumferential direction.
  • the engagement of the teeth of the outer wheel and the inner wheel (s) assigned to one another should advantageously begin in the area of the intersection of the tip circles.
  • the tooth mesh does not extend absolutely exactly to the intersection of the tip circles.
  • the invention further provides that the inlet opening of the pump has a throttling effect. This means that the cross-section of the inlet opening is so small or reduced by installing a throttle that only a limited delivery rate can flow through the inlet into the pump for a given pressure drop.
  • an outlet is essentially assigned to each tooth gap which is created by the tooth engagement as a closed cell.
  • Several of these outlets open into a common pressure channel. In this case, separate pressure systems can be fed from the remaining outlet channels. If this is not the case, all outlets open into the common pressure channel. With a few exceptions, all outlets are secured by check valves with flow direction in the outlet direction. The only exception is the tooth cell closest to the intersection of the head circles or possibly the tooth next but one. These tooth cells open into the pressure channel. The distance between the outlets corresponds to the tooth pitch or is smaller than the tooth pitch.
  • valve arrangement is designed in such a way that the cells that arise in the outlet area only open towards the pressure chamber if, due to the progressive compression, the operating pressure of the pressure channel has also been reached in the respective cell.
  • the invention provides a tooth shape which ensures that the tooth flanks of the two toothed wheels located in the pressure region, ie between the intersections of the tip circles, come into such good contact with one another that the two between them Intermeshing flanks formed column can be referred to as hydraulically tight and the pump works silently.
  • the toothing is designed so that the tooth flanks that mesh with each other touch with as large a surface as possible or face each other. Therefore, adjacent tooth cells are sealed from each other by a gap that is as long as possible.
  • the toothing is designed as a cycloid toothing.
  • the cycloid toothing is designed with a curved line of engagement extending from the pitch point to the intersection of the two tip circles.
  • the radius of curvature of the line of engagement preferably assumes values which lie in their dimensions between the pitch circle radius of the inner toothing of the outer wheel and the pitch circle radius of the outer toothing of the inner wheel or wheels.
  • the line of engagement can be a curved line with a constantly changing radius of curvature within the specified limits or lie on a circle, the radius of which is defined within the previously specified limits.
  • the selected toothing has a special shape that falls outside the scope of the known, in that the pitch circles are shifted from the usual position.
  • the distance between the pitch circle and the tip circle, for the external toothing of the inner gear or the distance between the pitch circle and the root circle is significantly smaller than the gear module or the other tooth part.
  • the respectively larger section of the teeth to the smaller section advantageously behaves at least as 2: 1 and preferably as 3.5: 1 to 5: 1.
  • the center of curvature of the line of engagement describes an arc. This means that when the inner wheel is stationary and the outer wheel is rolling, the lines of engagement assigned to the individual teeth of the outer wheel, which are congruent to one another, each lie on an associated circle, the individual center points of the circle lying on a circle concentric with the outer wheel.
  • the invention provides a gear pump which has a delivery and output characteristic that increases with the speed only up to a certain speed. If this speed is exceeded, the rotating cells are only partially filled, and the filling decreases with increasing speed. Adverse consequences of the resulting cavitation and in particular the generally feared cavitation erosion are avoided by the selection according to the invention of only those gear pumps which have cells that are closed relative to one another, and by the design of the outlet area according to the invention with a plurality of outlet openings arranged in the circumferential direction, which are closed by check valves. As a result of this embodiment of the invention, the only partially filled cells only come into connection with the pressurized cells and the pressure chamber when the pressure of the partially filled cell has reached the system pressure. This prevents cavitation explosions.
  • the partial filling of the cells in the inlet area results from the throttling of the inlet channel which is always present there and which allows only a limited inlet oil flow which is not sufficient to completely fill each cell in the filling time specified by the pump speed.
  • throttles adapted to the application and operational purpose of the pump can also be used in the inlet duct.
  • the invention further provides that this throttle is bypassed by a bypass channel and that there is a valve in the bypass channel which is controlled by the outlet pressure of the control pump and which opens the bypass when the pressure in the outlet channel drops.
  • the throttle is set so that the amount of oil that is delivered by the control pump depends on the speed only up to a certain speed.
  • This z. B. taken into account the fact that the lubricating oil consumption of an engine in the lower speed ranges is speed-dependent. On the other hand, it is taken into account that the dependence of the lubricating oil consumption on the speed only exists up to a certain speed.
  • This threshold speed can be specified by dimensioning the throttle.
  • control system can be anyone, e.g. B. Adjust increased additional wear due to wear by determining the pressure drop and using it to open a bypass. By opening the bypass, the entire delivery capacity or an additional portion of the delivery capacity of the control pump can be accessed.
  • the outer wheel 1 is freely rotatably mounted in the housing 31.
  • the outer wheel 1 has an internal toothing 2.
  • the cylindrical housing 31 is closed on both sides by the covers 32 and 33.
  • the shaft 34 is rotatably supported and driven by a motor, not shown.
  • the inner wheel 3 is rotatably mounted on the shaft 34.
  • the inner wheel 3 has an external toothing 4 which is in engagement with the internal toothing 2 of the outer wheel 1.
  • the inlet channel 35 is connected to the tank 36 via a throttle 37.
  • a pressure control valve 39 is located in a bypass 38, which is connected in parallel to the throttle channel 37.
  • the piston 40 of the pressure control valve controls the opening of the bypass channel 38 to the tank 36 with its control edge 41.
  • the piston is on one side with a spring 42 charged.
  • the piston in control chamber 43 is acted upon by the outlet pressure via control line 44.
  • the outlet side of the pump will be discussed later.
  • the function of the pressure control valve 39 as a function of the outlet pressure is described below. As long as there is no or only a low outlet pressure in the control line 44 and the control chamber 43, the piston with its control edge releases the flow from the inlet 45 to the outlet 46.
  • Oil can now flow from the tank 36 to the pump both via the throttle 37 and the bypass channel 38.
  • the pressure in the control chamber 43 rises and the spring force overcomes, the inlet with respect to the outlet 46 is closed. Now only a throttled oil flow flows through the throttle 37 from the tank 36 to the inlet 35 of the pump. If the outlet pressure rises further, the pressure control valve acts as a pressure relief valve. The spring 42 is compressed so far that the front control edge 47 opens the pressure line 44 opposite the outlet 46 to the tank.
  • the pump forms - as shown in FIG. 1 - on the outlet side between the intermeshing teeth of the outer wheel 1 and inner wheel 3, four cells which are closed in the circumferential and axial directions and have been filled with oil via the inlet channel 35.
  • Four outlet kidneys 48.1, 48.2, 48.3, 48.4 are introduced into the cover 32. 2 shows only one of these outlet kidneys. This outlet kidney is designated there by 48.
  • Each of the outlet kidneys is connected to an outlet channel 49 drilled in the cover 33.
  • the outlet channel is also directed radially outwards, as shown in FIG. 2. Therefore, each outer channel 49 opens on the outside of the cover 33 as close as possible to the housing 31.
  • An outlet housing 50 is placed on the cover 33 in a pressure-tight manner.
  • the outlet housing 50 forms an outlet chamber which is connected to the outlet kidneys 48.1 to 48.4 via a pressure channel 49 and a bore 52.
  • the bores 52.1, 52.2 and 52.3 are each closed by a check valve.
  • the check valve is formed by an m-shaped plate which is screwed against the wall 53 of the outlet housing 50.
  • the tongues protruding from the common crossbeam 55 of the check valve 54 cover the bores 52. Therefore, these tongues act as check valves, which only release the connection from the respective pressure cell formed between the teeth, via outlet kidney 48, the respective pressure channel 49 and bore 52, when the pressure of the outlet cell is at least equal to the outlet pressure in the outlet chamber 51.
  • the last and smallest pressure cell is connected directly to the outlet chamber via kidney 48.4 and corresponding channels 49, 52.
  • the outlet chamber 51 has an outlet which leads into the common pressure channel 56.
  • the function of the pump at low pressure in the outlet chamber 51, the spring 42 moves the piston 40 - in FIG. 2 - to the left.
  • the pump now acts like a normal internal gear pump.
  • the oil flow flows through throttle 37 and bypass channel 38 to the inlet. All tooth gaps are filled to the maximum and expressed again on the outlet side. Whether the filling is complete or only partial depends on the throttle resistance of the throttle 37 and the bypass channel 38.
  • the throttle 63 is shown symbolically, which indicates that the bypass 38 also causes throttling, which at high speeds can lead to the fact that the tooth cells are only partially filled. This will be referred to later.
  • the pump is therefore particularly suitable for motor vehicles, in particular as a lubricating oil pump in motor vehicles. If this increases the need for lubricating oil, e.g. B. due to wear, the threshold pressure in the control pressure chamber 43 is only reached at a higher speed. Therefore, the bypass 38 is also closed later. As a result, the lubricating oil pump automatically adapts to an increased demand. The lubricating oil pump therefore meets the increasing need for lubricating oil throughout the life of the motor vehicle engine. On the other hand, the lubricating oil pump works economically even with a new engine with a relatively low need for lubricating oil, since with this lubricating oil pump it is avoided that an unneeded feed portion must be returned to the sump with losses.
  • control pump also meets other requirements of special operating conditions. So it can e.g. B. occur in motor vehicle engines that the lubricating oil heats up extremely or that engine parts must be cooled by lubricating oil due to special performance requirements.
  • a further short-circuit channel 58 is provided between the inlet 35 of the pump and the tank 36.
  • This short-circuit channel is an electromagnetically switched valve 59.
  • This valve is connected via signal line 60 and amplifier 61 z. B. actuated by a temperature sensor 62. Through the temperature sensor z. B. the oil temperature or the temperature of a machine part, for. B. pistons can be detected. It is also possible to use a different measuring instrument, e.g. B.
  • the message line can also be used to record other extraordinary operating conditions.
  • the valve 59 serves the purpose of meeting an extraordinary need. It is assumed here that the sum of the oil flow, which is conveyed by throttle 37 on the one hand and via bypass 38 on the other hand, is still throttled and therefore, despite the pressure control valve 39 being open, only a partial filling of the cells of the internal toothing takes place at speeds that exceed a certain threshold speed lie. Fig. 2 meets this requirement in that a further throttle 63 is indicated in the bypass 38.
  • Fig. 3 serves to explain the toothing, which is preferably used in the context of this invention.
  • the outer wheel 1 has an internal toothing 2, in which the inner wheel 3 meshes with its external toothing 4. Compared to the fixed outer gear 1, the inner wheel 3 rotating in the direction of arrow 24 moves in the direction of arrow 23.
  • the pitch circle 7 of the outer wheel like the pitch circle 8 of the inner wheel 3, is oriented in the direction of the tooth height 14 and the center points 17 and 25 of the pitch circles the center points 17 and 25 shifted, whereby a small section 16 of the teeth 2 and 4 and a much larger section 15 are formed, both of which complement each other to the tooth height 14 which is practically the same for both wheels 1 and 3.
  • the distance between pitch circle 7 and root circle 6 of outer wheel 1 and between pitch circle 8 and tip circle 9 of inner wheel 3 is preferably at least twice the distance between pitch circle 7 and tip circle 5 for outer wheel 1 or the distance between pitch circle 8 and the base circle 10 of the inner wheel, the ratio of the dimensions between the two tooth sections 15 and 16 preferably having a value between 3.5: 1 and 5: 1.
  • the line of engagement 11 extending through the pitch point 12 and the intersection 13 of the tip circles 5 and 9 lies on a circle with the radius 26 which starts from the center point 19 of the circle. If the inner wheel rolls on the stationary ring gear, the center of curvature 19 describes a circle 18 which is concentric with the pitch circle 7 of the outer wheel. The straight line 21 between the center of the ring gear 17 and the respective pitch point 12 intersects this circle at the current center of curvature. The radius of the circle 18 is determined by the specified conditions. The resulting form of gearing solves the task in an outstanding manner.

Abstract

A hydraulic variable capacity pump designed as a pump with an internal pinion, in which the teeth of the outer wheel (1) and the inner wheel (3) are inter-meshed between the intersection points of the tooth tip circles. As a result, tooth-cells are formed in the outlet region. The tooth-cells lead into an outlet passage common to all via outlet passages (48) which are arranged at a distance from the teeth and are closed each time by a return valve. The inlet is connected by two or three passages with the tank, the first of which is provided with a fixed throttle (37) and the second is controlled by a pressure control valve (39) operating as a function of the pressure prevailing in the compression chamber (51), and the third is controlled by an electromagnetic valve (59) as a function of other operating parameters.

Description

Die Erfindung betrifft einen Verbrennungsmotor, dessen Schmierölpumpe eine Regelpumpe für Hydraulikflüssigkeit ist, deren Fördermenge bis zu einem Grenzwert drehzahlabhängig ist und darüberhinaus unabhängig von der Drehzahl im wesentlichen konstant bleibt.The invention relates to an internal combustion engine, the lubricating oil pump of which is a control pump for hydraulic fluid, the flow rate of which is speed-dependent up to a limit value and, moreover, remains essentially constant regardless of the speed.

Aus der DE-OS-3 506 629 ist bekannt, im Einlaßkanal einer Innenzahnradpumpe eine verstellbare Saugdrossel anzuordnen. Die Austrittsbohrungen sind jeweils mit einem Rückschlagventil versehen. Die Verstellung der Saugdrossel erfolgt über einen Regelkreis in Abhängigkeit vom Ausgangssignal der Pumpe.From DE-OS-3 506 629 it is known to arrange an adjustable suction throttle in the inlet channel of an internal gear pump. The outlet bores are each provided with a check valve. The suction throttle is adjusted via a control loop depending on the output signal of the pump.

Aus der DE-OS-3 444 859 ist bekannt, eine Ölpumpe für einen Kraftfahrzeugmotor als Innenzahnradpumpe auszuführen. Bei dieser Pumpe wird die Verzahnung so ausgeführt, daß die Zähne im wesentlichen in dem Drehbereich, in welchem sich die Kopfkreise überschneiden, miteinander im Eingriff sind. Die Auslaßzellen werden mit einer Ventilanordnung verschlossen, bei welcher bei Erreichen des Betriebsdrucks infolge fortschreitender Kompression die Druckzellen in den Druckraum geöffnet werden. Um die Pumpe dem jeweiligen Einsatzund Betriebszweck anzupassen, wird dort vorgeschlagen, eine angepaßte Drossel in den Einlaßkanal einzusetzen.From DE-OS-3 444 859 it is known to design an oil pump for a motor vehicle engine as an internal gear pump. In this pump, the teeth are designed so that the teeth are in engagement with one another essentially in the rotational range in which the head circles overlap. The outlet cells are closed with a valve arrangement in which the pressure cells are opened into the pressure chamber when the operating pressure is reached due to progressive compression. In order to adapt the pump to the respective application and operational purpose, it is proposed there to use an adapted throttle in the inlet duct.

Aus der GB-A-2 069 609 ist eine Innenzahnradpumpe bekannt, bei welcher die Auslaßzellen gegenüber dem Schmierölkanal durch jeweils ein unabhängiges Rückschlagventil verschlossen sind.From GB-A-2 069 609 an internal gear pump is known in which the outlet cells are closed off from the lubricating oil channel by an independent check valve in each case.

Aus der DE-OS-2 758 376 ist eine Kolbenmaschine bekannt, deren Ölpumpe eine Innenläuferzahnradpumpe ist. Bei dieser Pumpe wird die Verzahnung so ausgeführt, daß ein Überdekkungsgrad von 1 angestrebt wird.A piston machine is known from DE-OS-2 758 376, the oil pump of which is an internal rotor gear pump. With this pump, the teeth are designed so that a degree of coverage of 1 is aimed for.

Verbrennungsmotoren werden mit sehr unterschiedlichen und stets wechselnden Betriebsparametern betrieben, angefangen vom Leerlauf bis zum Höchstlastbetrieb bei höchsten Drehzahlen. Das Schmierölsystem muß daher zwar den Höchstlastbedingungen genügen, soll aber andererseits in den niedrigeren Lastbereichen nicht unnötig viel Energie verbrauchen.Internal combustion engines are operated with very different and constantly changing operating parameters, from idling to maximum load operation at the highest speeds. The lubricating oil system must therefore meet the maximum load conditions, but, on the other hand, should not consume unnecessarily much energy in the lower load ranges.

An einen Verbrennungsmotor wird ferner die Forderung gestellt, daß er eine lange Lebensdauer ohne fachmännische Wartung hat. Dem steht entgegen, daß der Verbrennungsmotor einem Verschleiß unterworfen ist, der zur Steigerung des Schmierölverbrauchs und zum Druckabfall im Schmierölsystem führt. Die Schmierölpumpe muß daher auch diesem im Laufe der Standzeit zunehmenden Bedarf angepaßt sein. Das führt dazu, daß auch dieser Förderanteil der Schmierölpumpe, der nicht benötigt wird, zu entsprechenden Energieverlusten führt.An internal combustion engine is also required to have a long service life without expert maintenance. This is opposed to the fact that the internal combustion engine is subject to wear, which leads to an increase in lubricating oil consumption and to a drop in pressure in the lubricating oil system. The lubricating oil pump must therefore also be adapted to this increasing demand in the course of the service life. This leads to the fact that this delivery portion of the lubricating oil pump, which is not required, leads to corresponding energy losses.

Aufgabe der Erfindung ist, ein Schmierölsystem für einen Verbrennungsmotor zu schaffen, bei welchem einerseits die Schmierölpumpe eine ausreichende Schmierölmenge in allen Betriebszuständen liefert, andererseits eine unnötige, verlustbehaftete Förderung jedoch vermieden wird.The object of the invention is to provide a lubricating oil system for an internal combustion engine, in which, on the one hand, the lubricating oil pump supplies a sufficient amount of lubricating oil in all operating states, on the other hand, however, unnecessary, lossy delivery is avoided.

Diese Aufgabe wird gelöst durch die kennzeichnenden Merkmale des Anspruchs 1.This object is achieved by the characterizing features of claim 1.

Bei dieser Innenzahnradpumpe wird die Verzahnung so ausgeführt, daß die Zahnflanken der Zähne, die zwischen den Schnittpunkten der Kopfkreise liegen, miteinander in Eingriff sind und daher einzelne Zellen in ihren Zahnlücken bilden, die in Umfangsrichtung voneiander abgeschlossen sind. Dabei soll der Eingriff der jeweils einander zugeordneten Zähne des Au- βenrades und des oder der Innenräder mit Vorteil bereits im Bereich des Schnittpunktes der Kopfkreise beginnen. Es ist - je nach Anforderungen - möglich, daß der Zahneingriff sich nicht absolut genau bis zu den Schnittpunkten der Kopfkreise erstreckt. Hierbei ist zu berücksichtigen, daß ein Eingriff nicht unbedingt eine mechanisch feste Berührung voraussetzt, vielmehr werden Zahnräder bereits dann als in Eingriff stehend bezeichnet, wenn der Abstand ihrer Flanken einen so engen Spalt ergibt, daß dieser unter Berücksichtigung der Viskosität der Hydraulikflüssigkeit hydraulisch als Dichtung anzusehen ist.In this internal gear pump, the toothing is carried out so that the tooth flanks of the teeth, which lie between the intersections of the tip circles, are in engagement with one another and therefore form individual cells in their tooth gaps, which are closed off from one another in the circumferential direction. The engagement of the teeth of the outer wheel and the inner wheel (s) assigned to one another should advantageously begin in the area of the intersection of the tip circles. Depending on the requirements, it is possible that the tooth mesh does not extend absolutely exactly to the intersection of the tip circles. It must be taken into account here that an intervention does not necessarily require a mechanically firm contact, rather gears are already referred to as being in engagement when the distance between their flanks results in a gap which is so narrow that this can be considered hydraulically as a seal, taking into account the viscosity of the hydraulic fluid is.

Die Erfindung sieht weiterhin vor, daß die Einlaßöffnung der Pumpe drosselnd wirkt. Das heißt, der Querschnitt der Einlaßöffnung ist so klein bzw. durch Einbau einer Drossel so verkleinert, daß bei gegebenem Druckgefälle lediglich eine begrenzte Fördermenge durch den Einlaß in die Pumpe einströmen kann.The invention further provides that the inlet opening of the pump has a throttling effect. This means that the cross-section of the inlet opening is so small or reduced by installing a throttle that only a limited delivery rate can flow through the inlet into the pump for a given pressure drop.

Weiterhin ist auf der Auslaßseite der Pumpe im wesentlichen jeder Zahnlücke, die durch den Zahneingriff als geschlossene Zelle entsteht, ein Auslaß zugeordnet. Mehrere dieser Auslässe münden in einen gemeinsamen Druckkanal. In diesem Falle können von den restlichen Auslaßkanälen separate Drucksysteme gespeist werden. Sofern das nicht der Fall ist, münden sämtliche Auslässe in den gemeinsamen Druckkanal. Mit wenigen Ausnahmen sind sämtliche Auslässe durch Rückschlagventile gesichert mit Durchflußrichtung in Auslaßrichtung. Eine Ausnahme bildet lediglich die dem Schnittpunkt der Kopfkreise nächste Zahnzelle bzw. eventuell auch noch die übernächste Zahnzelle. Diese Zahnzellen münden frei in den Druckkanal. Der Abstand der Auslässe entspricht der Zahnteilung bzw. ist kleiner als die Zahnteilung.Furthermore, on the outlet side of the pump, an outlet is essentially assigned to each tooth gap which is created by the tooth engagement as a closed cell. Several of these outlets open into a common pressure channel. In this case, separate pressure systems can be fed from the remaining outlet channels. If this is not the case, all outlets open into the common pressure channel. With a few exceptions, all outlets are secured by check valves with flow direction in the outlet direction. The only exception is the tooth cell closest to the intersection of the head circles or possibly the tooth next but one. These tooth cells open into the pressure channel. The distance between the outlets corresponds to the tooth pitch or is smaller than the tooth pitch.

Es sind also - in Drehrichtung - mehrere Auslässe hintereinander angeordnet und jeweils durch eine Ventilanordnung verschlossen. Die Ventilanordnung ist so ausgebildet, daß die im Auslaßbereich entstehenden Zellen gegenüber dem Druckraum nur öffnen, wenn infolge der fortschreitenden Kompression der Betriebsdruck des Druckkanals auch in der jeweiligen Zelle erreicht ist.So there are - in the direction of rotation - several outlets arranged one behind the other and each closed by a valve arrangement. The valve arrangement is designed in such a way that the cells that arise in the outlet area only open towards the pressure chamber if, due to the progressive compression, the operating pressure of the pressure channel has also been reached in the respective cell.

Weiterhin stellt die Erfindung eine Zahnform bereit, die gewährleistet, daß die im Druckbereich, d. h. zwischen den Schnittpunkten der Kopfkreise, befindlichen Zahnflanken der beiden Zahnräder in einen so guten Kontakt miteinander kommen, daß die zwischen zwei miteinander kämmenden Flanken gebildeten Spalte als hydraulisch dicht bezeichnet werden können und die Pumpe geräuschlos arbeitet. Dabei wird die Verzahnung so ausgebildet, daß die Zahnflanken, die miteinander kämmen, sich mit einer möglichst großen Fläche berühren bzw. einander gegenüberliegen. Daher werden benachbarte Zahnzellen durch einen möglichst langen Spalt voneinander abgedichtet. Hierzu wird die Verzahnung als Zykloidenverzahnung ausgeführt. In einer bevorzugten Ausführung ist die Zykloidenverzahnung mit gekrümmter, vom Wälzpunkt bis zum Schnittpunkt der beiden Kopfkreise verlaufender Eingriffslinie ausgebildet. Vorzugsweise nimmt der Krümmungsradius der Eingriffslinie Werte an, die in ihren Abmessunqen zwischen dem Wälzkreisradius der Innenverzahnung des Außenrades und dem Wälzkreisradius der Außenverzahnung des oder der Innenräder liegen.Furthermore, the invention provides a tooth shape which ensures that the tooth flanks of the two toothed wheels located in the pressure region, ie between the intersections of the tip circles, come into such good contact with one another that the two between them Intermeshing flanks formed column can be referred to as hydraulically tight and the pump works silently. The toothing is designed so that the tooth flanks that mesh with each other touch with as large a surface as possible or face each other. Therefore, adjacent tooth cells are sealed from each other by a gap that is as long as possible. For this purpose, the toothing is designed as a cycloid toothing. In a preferred embodiment, the cycloid toothing is designed with a curved line of engagement extending from the pitch point to the intersection of the two tip circles. The radius of curvature of the line of engagement preferably assumes values which lie in their dimensions between the pitch circle radius of the inner toothing of the outer wheel and the pitch circle radius of the outer toothing of the inner wheel or wheels.

Die Eingriffslinie kann eine gekrümmte Linie mit sich innerhalb der angegebenen Grenzen stetig änderndem Krümmungsradius sein oder auf einem Kreis liegen, dessen Radius innerhalb der vorhergehend angegebenen Grenzen festgelegt ist.The line of engagement can be a curved line with a constantly changing radius of curvature within the specified limits or lie on a circle, the radius of which is defined within the previously specified limits.

In einer Weiterbildungsform hat die gewählte Verzahnung eine besondere, aus dem Rahmen des Bekannten fallende Form, indem die Wälzkreise gegenüber der üblichen Lage verschoben sind. Bei der Innenverzahnung des Au- ßenzahnrades ist der Abstand zwischen Wälzkreis und Kopfkreis, bei der Außenverzahnung des oder der Innenräder der Abstand zwischen Wälzkreis und Fußkreis deutlich kleienr als der Verzahnungsmodul bzw. der jeweils andere Zahnteil. Vorteilhaft verhält sich der jeweils größere Teilabschnitt der Zähne zum jeweils kleineren Teilabschnitt mindestens wie 2 : 1 und vorzugsweise wie 3,5 : 1 bis 5 : 1.In a form of further training, the selected toothing has a special shape that falls outside the scope of the known, in that the pitch circles are shifted from the usual position. For the internal toothing of the external gear, the distance between the pitch circle and the tip circle, for the external toothing of the inner gear or the distance between the pitch circle and the root circle is significantly smaller than the gear module or the other tooth part. The respectively larger section of the teeth to the smaller section advantageously behaves at least as 2: 1 and preferably as 3.5: 1 to 5: 1.

Bei stillstehendem Außenrad und abwälzendem Innenrad beschreibt der Krümmungsmittelpunkt der Eingriffslinie einen Kreisbogen. Das heißt, daß bei stillstehendem Innenrad und abwälzendem Außenrad die den einzelnen Zähnen des Außenrades zugeordneten, zueinander kongruenten Eingriffslinien jeweils auf einem zugeordneten Kreis liegen, wobei die einzelnen Kreismittelpunkte auf einem zum Außenrad konzentrischen Kreis liegen.When the outer wheel is stationary and the inner wheel is rolling, the center of curvature of the line of engagement describes an arc. This means that when the inner wheel is stationary and the outer wheel is rolling, the lines of engagement assigned to the individual teeth of the outer wheel, which are congruent to one another, each lie on an associated circle, the individual center points of the circle lying on a circle concentric with the outer wheel.

Durch die Erfindung wird eine Zahnradpumpe geschaffen, die nur bis zu einer bestimmten Drehzahl eine mit der Drehzahl ansteigende Förder- und Leistungscharakteristik hat. Bei Überschreiten dieser Drehzahl werden die umlaufenden Zellen nur teilgefüllt, und zwar nimmt die Füllung mit Erhöhung der Drehzahl ab. Nachteilige Folgen der dadurch entstehenden Kavitation und insbesondere die allgemein befürchtete Kavitationserosion werden vermieden durch die erfindungsgemäße Auswahl nur solcher Zahnradpumpen, die relativ zueinander abgeschlossene Zellen haben, sowie durch die erfindungsgemäße Gestaltung des Auslaßbereiches mit mehreren in Umfangsrichtung angeordneten Auslaßöffnungen, die durch Rückschlagventile verschlossen sind. Durch diese Ausgestaltung der Erfindung geraten die nur teilgefüllten Zellen erst dann mit den unter Druck stehenden Zellen und dem Druckraum in Verbindung, wenn der Druck der teilgefüllten Zelle den Systemdruck erreicht hat. Dadurch werden Kavitationsimplosionen vermieden.The invention provides a gear pump which has a delivery and output characteristic that increases with the speed only up to a certain speed. If this speed is exceeded, the rotating cells are only partially filled, and the filling decreases with increasing speed. Adverse consequences of the resulting cavitation and in particular the generally feared cavitation erosion are avoided by the selection according to the invention of only those gear pumps which have cells that are closed relative to one another, and by the design of the outlet area according to the invention with a plurality of outlet openings arranged in the circumferential direction, which are closed by check valves. As a result of this embodiment of the invention, the only partially filled cells only come into connection with the pressurized cells and the pressure chamber when the pressure of the partially filled cell has reached the system pressure. This prevents cavitation explosions.

Die Teilfüllung der Zellen im Einlaßbereich ergibt sich durch die dort stets vorhandene Drosselung des Einlaßkanals, die nur einen begrenzten Einlaß-Ölstrom zuläßt, der in der durch die Pumpendrehzahl vorgegebenen Füllzeit nicht zur vollständigen Füllung jeder Zelle ausreicht. Es können jedoch auch dem Einsatz- und Betriebszweck der Pumpe angepaßte Drosseln im Einlaßkanal eingesetzt werden. Insbesondere ist es in einer vorteilhaften Weiterbildung der Erfindung möglich, die Drossel einstellbar auszuführn, so daß man die Förderleistung der Pumpe dem jeweiligen Bedarf anpassen kann. Ebenso ist es vorteilhaft, eine derart verstellbare Drossel in einen Regelkreis einzubauen, durch den die Fördermenge konstant gehalten oder einem vorgegebenen Sollwert angepaßt wird.The partial filling of the cells in the inlet area results from the throttling of the inlet channel which is always present there and which allows only a limited inlet oil flow which is not sufficient to completely fill each cell in the filling time specified by the pump speed. However, throttles adapted to the application and operational purpose of the pump can also be used in the inlet duct. In particular, in an advantageous development of the invention, it is possible to design the throttle in an adjustable manner, so that the delivery capacity of the pump can be adapted to the respective requirement. It is also advantageous to install a throttle that is adjustable in this way in a control circuit, by means of which the delivery rate is kept constant or is adapted to a predetermined desired value.

Die Erfindung sieht nun weiterhin vor, daß diese Drossel durch einen Bypasskanal umgangen wird und daß in dem Bypasskanal ein Ventil liegt, das durch den Auslaßdruck der Regelpumpe gesteuert wird und das den Bypass aufsteuert, wenn der Druck in dem Auslaßkanal abfällt.The invention further provides that this throttle is bypassed by a bypass channel and that there is a valve in the bypass channel which is controlled by the outlet pressure of the control pump and which opens the bypass when the pressure in the outlet channel drops.

Bei diesem Regelsystem wird die Drossel so eingestellt, daß die Ölmenge, die durch die Regelpumpe gefördert wird, nur bis zu einer bestimmten Drehzahl von der Drehzahl abhängt. Dadurch wird z. B. der Tatsache Rechnung getragen, daß der Schmierölverbrauch eines Motors in den unteren Drehzahlbereichen drehzahlabhängig ist. Andererseits wird berücksichtigt, daß die Abhängigkeit des Schmierölverbrauchs von der Drehzahl nur bis zu einer gewissen Drehzahl besteht. Diese Schwelldrehzahl läßt sich durch Dimensionierung der Drossel vorgeben.In this control system, the throttle is set so that the amount of oil that is delivered by the control pump depends on the speed only up to a certain speed. This z. B. taken into account the fact that the lubricating oil consumption of an engine in the lower speed ranges is speed-dependent. On the other hand, it is taken into account that the dependence of the lubricating oil consumption on the speed only exists up to a certain speed. This threshold speed can be specified by dimensioning the throttle.

Andererseits kann sich das Regelsystem jedem, z. B. durch Verschleiß gesteigerten Mehrbedarf anpassen, indem der Druckabfall ermittelt und zum Öffnen eines Bypass genutzt wird. Durch das Öffnen des Bypass kann die gesamte Förderkapazität oder ein zusätzlicher Anteil der Förderkapazität der Regelpumpe erschlossen werden.On the other hand, the control system can be anyone, e.g. B. Adjust increased additional wear due to wear by determining the pressure drop and using it to open a bypass. By opening the bypass, the entire delivery capacity or an additional portion of the delivery capacity of the control pump can be accessed.

In einer vorteilhaften Ausführung wird vorgesehen, daß durch den Bypass lediglich ein gesteigerter Anteil der Förderkapazität erschlossen wird. Es soll darüberhinaus auch die Möglichkeit geschaffen werden, durch weitere Steigerung der Förderung einen Sonderbedarf zu erfüllen, der nicht druckabhängig ist. So ist es z. B. bei Kraftfahrzeugmotoren möglich, den Schmierölumlauf zu steigern, wenn die Schmieröltemperatur einen bestimmten Wert (Schwelltemperatur) überschreitet. Hierzu wird ein weiterer Kurzschlußkanal im Zulauf vorgesehen, der durch ein elektromagnetisches Ventil betätigt wird.In an advantageous embodiment it is provided that only an increased proportion of the conveying capacity is opened up by the bypass. In addition, the possibility is to be created to meet a special need by further increasing the funding, which is not dependent on pressure. So it is z. B. in motor vehicle engines possible to increase the lubricating oil circulation when the lubricating oil temperature exceeds a certain value (threshold temperature). For this purpose, a further short-circuit channel is provided in the inlet, which is actuated by an electromagnetic valve.

Im folgenden wird die Erfindung anhand eines Ausführungsbeispiels beschrieben.In the following the invention is based on a Described embodiment.

Es zeigenShow it

  • Fig. 1, 2 den Radialschnitt und Axialschnitt;1, 2 the radial section and axial section;
  • Fig. 3 als Detail von Fig. 1 die Ausführung der Verzahnung.Fig. 3 as a detail of Fig. 1, the execution of the toothing.

In dem Gehäuse 31 ist das Außenrad 1 frei drehbar gelagert. Das Außenrad 1 besitzt eine Innenverzahnung 2. Das zylindrische Gehäuse 31 wird beidseitig durch die Deckel 32 und 33 abgeschlossen. In dem Deckel 32 ist die Welle 34 drehbar gelagert und durch einen nicht dargestellten Motor angetrieben. Auf der Welle 34 ist drehfest gelagert das Innenrad 3. Das Innenrad 3 besitzt eine Außenverzahnung 4, die mit der Innenverzahnung 2 des Außenrades 1 in Eingriff ist. In dem Deckel 33 befindet sich der Einlaßkanal 35 (s. auch Fig. 1).The outer wheel 1 is freely rotatably mounted in the housing 31. The outer wheel 1 has an internal toothing 2. The cylindrical housing 31 is closed on both sides by the covers 32 and 33. In the cover 32, the shaft 34 is rotatably supported and driven by a motor, not shown. The inner wheel 3 is rotatably mounted on the shaft 34. The inner wheel 3 has an external toothing 4 which is in engagement with the internal toothing 2 of the outer wheel 1. In the cover 33 there is the inlet channel 35 (see also FIG. 1).

Der Einlaßkanal 35 steht mit dem Tank 36 über eine Drossel 37 in Verbindung. In einem Bypass 38, der parallel zu dem Drosselkanal 37 geschaltet ist, befindet sich ein Drucksteuerventil 39. Der Kolben 40 des Drucksteuerventils steuert mit seiner Steuerkante 41 die Öffnung des Bypasskanals 38 zum Tank 36. Der Kolben ist auf der einen Seite mit einer Feder 42 belastet. Auf der gegenüberliegenden Seite wird der Kolben im Steuerraum 43 mit dem Auslaßdruck über Steuerleitung 44 beaufschlagt. Auf die Auslaßseite der Pumpe wird später eingegangen. Die Funktion des Drucksteuerventils 39 in seiner Abhängigkeit vom Auslaßdruck wird nachfolgend beschrieben. Solange kein oder nur ein geringer Auslaßdruck in der Steuerleitung 44 und dem Steuerraum 43 herrscht, gibt der Kolben mit seiner Steuerkante den Durchfluß vom Eingang 45 zum Auslaß 46 frei. Es kann nunmehr Öl aus dem Tank 36 zur Pumpe sowohl über die Drossel 37 als auch Bypasskanal 38 fließen. Wenn der Druck im Steuerraum 43 ansteigt und die Federkraft überwindet, so wird der Einlaß gegenüber dem Auslaß 46 verschlossen. Nunmehr fließt lediglich noch ein gedrosselter Ölstrom über die Drossel 37 vom Tank 36 zum Einlaß 35 der Pumpe. Steigt der Auslaßdruck noch weiter an, so wirkt das Drucksteuerventil als Druckbegrenzungsventil. Die Feder 42 wird so weit zusammengedrückt, daß die vordere Steuerkante 47 die Druckleitung 44 gegenüber dem Auslaß 46 zum Tank öffnet.The inlet channel 35 is connected to the tank 36 via a throttle 37. A pressure control valve 39 is located in a bypass 38, which is connected in parallel to the throttle channel 37. The piston 40 of the pressure control valve controls the opening of the bypass channel 38 to the tank 36 with its control edge 41. The piston is on one side with a spring 42 charged. On the opposite side, the piston in control chamber 43 is acted upon by the outlet pressure via control line 44. The outlet side of the pump will be discussed later. The function of the pressure control valve 39 as a function of the outlet pressure is described below. As long as there is no or only a low outlet pressure in the control line 44 and the control chamber 43, the piston with its control edge releases the flow from the inlet 45 to the outlet 46. Oil can now flow from the tank 36 to the pump both via the throttle 37 and the bypass channel 38. When the pressure in the control chamber 43 rises and the spring force overcomes, the inlet with respect to the outlet 46 is closed. Now only a throttled oil flow flows through the throttle 37 from the tank 36 to the inlet 35 of the pump. If the outlet pressure rises further, the pressure control valve acts as a pressure relief valve. The spring 42 is compressed so far that the front control edge 47 opens the pressure line 44 opposite the outlet 46 to the tank.

Zur Auslaßseite der Pumpe:To the outlet side of the pump:

Die Pumpe bildet - wie Fig. 1 zeigt - auf der Auslaßseite zwischen den miteinander kämmenden Zähnen des Außenrades 1 und tnnenrades 3 vier in Umfangsrichtung und Axialrichtung abgeschlossene Zellen, die über Einlaßkanal 35 mit Öl gefüllt worden sind. In den Deckel 32 sind vier Auslaßnieren 48.1, 48.2, 48.3, 48.4 eingebracht. Im Schnitt nach Fig. 2 ist nur eine dieser Auslaßnieren zu sehen. Diese Auslaßniere ist dort mit 48 bezeichnet. Jede der Auslaßnieren steht mit einem in den Deckel 33 gebohrten Auslaßkanal 49 in Verbindung. Der Auslaßkanal ist jeweils auch radial nach außen gerichtet, wie Fig. 2 zeigt. Daher mündet jeder Außenkanal 49 auf der Außenseite des Deckels 33 möglichst nah am Gehäuse 31. Auf den Deckel 33 ist ein Auslaßgehäuse 50 druckdicht aufgesetzt. Das Auslaßgehäuse 50 bildet eine Auslaßkammer, die mit den Auslaßnieren 48.1 bis 48.4 jeweils über einen Druckkanal 49 und eine Bohrung 52 in Verbindung steht. Die Bohrungen 52.1, 52.2 und 52.3 (vgl. Fig. 1) sind jeweils durch ein Rückschlagventil verschlossen. Das Rückschlagventil wird gebildet durch ein m-förmiges Blech, das gegen die Wand 53 des Auslaßgehäuses 50 geschraubt ist. Die von dem gemeinsamen Querbalken 55 des Rückschlagventils 54 abstehenden Zungen verdecken die Bohrungen 52. Daher wirken diese Zungen als Rückschlagventile, die die Verbindung von der jeweiligen, zwischen den Zähnen gebildeten Druckzelle, über Auslaßniere 48, dem jeweiligen Druckkanal 49 und Bohrung 52 nur freigeben, wenn der Druck der Auslaßzelle dem Auslaßdruck in der Auslaßkammer 51 zumindest gleich ist. Die letzte und kleinste Druckzelle steht über Niere 48.4 und entsprechende Kanäle 49, 52 direkt mit der Auslaßkammer in Verbindung.The pump forms - as shown in FIG. 1 - on the outlet side between the intermeshing teeth of the outer wheel 1 and inner wheel 3, four cells which are closed in the circumferential and axial directions and have been filled with oil via the inlet channel 35. Four outlet kidneys 48.1, 48.2, 48.3, 48.4 are introduced into the cover 32. 2 shows only one of these outlet kidneys. This outlet kidney is designated there by 48. Each of the outlet kidneys is connected to an outlet channel 49 drilled in the cover 33. The outlet channel is also directed radially outwards, as shown in FIG. 2. Therefore, each outer channel 49 opens on the outside of the cover 33 as close as possible to the housing 31. An outlet housing 50 is placed on the cover 33 in a pressure-tight manner. The outlet housing 50 forms an outlet chamber which is connected to the outlet kidneys 48.1 to 48.4 via a pressure channel 49 and a bore 52. The bores 52.1, 52.2 and 52.3 (see FIG. 1) are each closed by a check valve. The check valve is formed by an m-shaped plate which is screwed against the wall 53 of the outlet housing 50. The tongues protruding from the common crossbeam 55 of the check valve 54 cover the bores 52. Therefore, these tongues act as check valves, which only release the connection from the respective pressure cell formed between the teeth, via outlet kidney 48, the respective pressure channel 49 and bore 52, when the pressure of the outlet cell is at least equal to the outlet pressure in the outlet chamber 51. The last and smallest pressure cell is connected directly to the outlet chamber via kidney 48.4 and corresponding channels 49, 52.

Die Auslaßkammer 51 hat einen Auslaß, der in den gemeinsamen Druckkanal 56 führt.The outlet chamber 51 has an outlet which leads into the common pressure channel 56.

Zur Funktion der Pumpe: Bei niedrigem Druck in der Auslaßkammer 51 verschiebt die Feder 42 den Kolben 40 - in Fig. 2 - nach links. Die Pumpe wirkt nun wie eine normale Innenzahnradpumpe. Der Ölstrom fließt über Drossel 37 und Bypasskanal 38 zum Einlaß. Sämtliche Zahnlücken werden maximal gefüllt und auf der Auslaßseite wieder ausgedrückt. Ob die Füllung vollständig oder nur teilweise ist, hängt vom Drosselwiderstand der Drossel 37 und des Bypasskanals 38 ab. In Fig. 2 ist symbolisch die Drossel 63 gezeigt, die andeutet, daß auch der Bypass 38 eine Drosselung bewirkt, die bei hohen Drehzahlen dazu führen kann, daß die Zahnzellen nur teilweie gefüllt werden. Hierauf wird später noch verwiesen.The function of the pump: at low pressure in the outlet chamber 51, the spring 42 moves the piston 40 - in FIG. 2 - to the left. The pump now acts like a normal internal gear pump. The oil flow flows through throttle 37 and bypass channel 38 to the inlet. All tooth gaps are filled to the maximum and expressed again on the outlet side. Whether the filling is complete or only partial depends on the throttle resistance of the throttle 37 and the bypass channel 38. In Fig. 2, the throttle 63 is shown symbolically, which indicates that the bypass 38 also causes throttling, which at high speeds can lead to the fact that the tooth cells are only partially filled. This will be referred to later.

Wenn der Druck in Auslaßkammer 51 steigt, so wird zunächst der Bypass 38 verschlossen. Es gelangt nunmehr lediglich noch ein stark gedrosselter Ölstrom auf die Einlaßseite. Daher werden die Zahnlücken auf der Einlaßseite lediglich noch teilgefüllt bzw. noch weniger gefüllt. Im übrigen herrscht in den Zahnlücken ein Vakuum. Das hat zur Folge, daß der Druck in den Zahnzellen auf der Auslaßseite zunächst niedriger als der Druck in der Auslaßkammer 51 ist. Daher bleiben die Zungen des Rückschlagventils 54 geschlossen. Mit fortschreitender Verkleinerung der Zellen auf der Auslaßseite steigt der Druck in den Zellen jedoch an. Es öffnet jeweils nur die Zunge des Rückschlagventils, für die der Druck der Zelle größer oder gleich dem Druck in der Auslaßkammer 51 ist. Das hat zur Folge, daß die Pumpe nunmehr lediglich noch eine drehzahlunabhängige, konstante Ölmenge liefert. Es ist daher auch bei steigender Drehzahl nicht erforderlich, eine überschießende Ölmenge unter entsprechenden Leistungsverlusten abzuführen, wie dies bei herkömmlichen Systemen der Fall ist. Die Pumpe eignet sich daher insbesondere für Kraftfahrzeuge, und zwar insbesondere als Schmierölpumpe in Kraftfahrzeugen. Wenn hierbei der Schmierölbedarf steigt, z. B. infolge Verschleiß, so wird der Schwelldruck in der Steuerdruckkammer 43 erst bei höherer Drehzahl erreicht. Daher wird auch der Bypass 38 erst später verschlossen. Das hat zur Folge, daß die Schmierölpumpe sich automatisch einem gesteigerten Bedarf anpaßt. Die Schmierölpumpe wird daher während der gesamten Lebensdauer des Kraftfahrzeugmotors dem sich steigernden Schmierölbedarf gerecht. Andererseits arbeitet die Schmierölpumpe auch bei neuem Motor mit relativ geringem Schmierölbedarf wirtschaftlich, da bei dieser Schmierölpumpe vermieden wird, daß ein nicht benötigter Förderanteil verlustbehaftet wieder in den Sumpf zurückgeführt werden muß.When the pressure in the outlet chamber 51 rises, the bypass 38 is first closed. Now there is only a strongly restricted oil flow on the inlet side. Therefore, the tooth gaps on the inlet side are only partially filled or filled even less. There is also a vacuum in the tooth gaps. As a result, the pressure in the tooth cells on the outlet side is initially lower than the pressure in the outlet chamber 51. Therefore, the tongues of the check valve 54 remain closed. However, as the size of the cells on the outlet side shrinks, the pressure in the cells increases. Only the tongue of the check valve opens for which the pressure of the cell is greater than or equal to the pressure in the outlet chamber 51. The result of this is that the pump now only delivers a constant, independent oil quantity. It is therefore not necessary, even with increasing speed, to excess oil to dissipate corresponding power losses, as is the case with conventional systems. The pump is therefore particularly suitable for motor vehicles, in particular as a lubricating oil pump in motor vehicles. If this increases the need for lubricating oil, e.g. B. due to wear, the threshold pressure in the control pressure chamber 43 is only reached at a higher speed. Therefore, the bypass 38 is also closed later. As a result, the lubricating oil pump automatically adapts to an increased demand. The lubricating oil pump therefore meets the increasing need for lubricating oil throughout the life of the motor vehicle engine. On the other hand, the lubricating oil pump works economically even with a new engine with a relatively low need for lubricating oil, since with this lubricating oil pump it is avoided that an unneeded feed portion must be returned to the sump with losses.

Darüber hinaus wird die Regelpumpe auch weiteren Bedarfsanforderungen besonderer Betriebszustände gerecht. So kann es z. B. in Kraftfahrzeugmotoren vorkommen, daß sich das Schmieröl außerordentlich erwärmt oder daß Motorteile durch Schmieröl infolge besonderer Leistungsanforderungen gekühlt werden müssen. Für diesen Fall ist - wie Fig. 2 zeigt - ein weiterer Kurzschlußkanal 58 zwischen dem Einlaß 35 der Pumpe und dem Tank 36 vorgesehen. In diesem Kurzschlußkanal liegt ein elektromagnetisch geschaltetes Ventil 59. Dieses Ventil wird über Meldeleitung 60 und Verstärker 61 z. B. durch einen Temperaturfühler 62 betätigt. Durch den Temperaturfühler kann z. B. die Öltemperatur oder die Temperatur eines Maschinenteils, z. B. Kolbens, erfaßt werden. Ebenso ist es möglich, statt des Temperaturfühlers 62 ein anderes Meßinstrument, z. B. Drehzahlzähler zu verwenden. Ebenso kann die Meldeleitung genutzt werden, um andere außerordentliche Betriebszustände zu erfassen. In jedem Falle dient das Ventil 59 dem Zweck, einen außerordentlichen Bedarf zu decken. Hierbei wird davon ausgegangen, daß auch die Summe des Ölstroms, der durch Drossel 37 einerseits und über Bypass 38 andererseits gefördert wird, noch gedrosselt ist und daher trotz geöffneten Drucksteuerventils 39 lediglich eine Teilfüllung der Zellen der Innenverzahnung stattfindet bei Drehzahlen, die über einer gewissen Schwelldrehzahl liegen. Fig. 2 wird dieser Voraussetzung dadurch gerecht, daß auch eine weitere Drossel 63 im Bypass 38 angedeutet ist.In addition, the control pump also meets other requirements of special operating conditions. So it can e.g. B. occur in motor vehicle engines that the lubricating oil heats up extremely or that engine parts must be cooled by lubricating oil due to special performance requirements. In this case, as shown in FIG. 2, a further short-circuit channel 58 is provided between the inlet 35 of the pump and the tank 36. In this short-circuit channel is an electromagnetically switched valve 59. This valve is connected via signal line 60 and amplifier 61 z. B. actuated by a temperature sensor 62. Through the temperature sensor z. B. the oil temperature or the temperature of a machine part, for. B. pistons can be detected. It is also possible to use a different measuring instrument, e.g. B. Speed counter to use. The message line can also be used to record other extraordinary operating conditions. In any case, the valve 59 serves the purpose of meeting an extraordinary need. It is assumed here that the sum of the oil flow, which is conveyed by throttle 37 on the one hand and via bypass 38 on the other hand, is still throttled and therefore, despite the pressure control valve 39 being open, only a partial filling of the cells of the internal toothing takes place at speeds that exceed a certain threshold speed lie. Fig. 2 meets this requirement in that a further throttle 63 is indicated in the bypass 38.

Es wurde bereits darauf hingewiesen, daß die Wirksamkeit der Pumpe davon abhängt, daß die Verzahnung so ausgebildet ist, daß die Zähne im Auslaßbereich zwischen den Schnittpunkten der Kopfkreise miteinander in Eingriff sind und - unter Berücksichtigung der Viskosität des Hydrauliköls - abgeschlossene Zellen bilden.It has already been pointed out that the effectiveness of the pump depends on the toothing being designed in such a way that the teeth in the outlet area between the intersections of the head circles are in engagement with one another and - taking into account the viscosity of the hydraulic oil - form closed cells.

Fig. 3 dient der Erläuterung der Verzahnung, die im Rahmen dieser Erfindung vorzugsweise Anwendung findet.Fig. 3 serves to explain the toothing, which is preferably used in the context of this invention.

Das Außenrad 1 weist eine Innenverzahnung 2 auf, in der das Innenrad 3 mit seiner Außenverzahnung 4 kämmt. Gegenüber dem feststehenden Außenzahnrad 1 bewegt sich das in Pfeilrichtung 24 rotierende Innenrad 3 in Richtung des Pfeils 23. Der Wälzkreis 7 des Außenrades ist ebenso wie der Wälzkreis 8 des Innenrades 3 bezogen auf die Zahnhöhe 14 und die Mittelpunkte 17 und 25 der Wälzkreise in Richtung auf die Mittelpunkte 17 und 25 verschoben, wodurch ein kleiner Teilabschnitt 16 der Zähne 2 und 4 und ein wesentlich größerer Teilabschnitt 15 entsteht, die sich beide zur für beide Räder 1 und 3 praktisch gleichen Zahnhöhe 14 ergänzen. Bevorzugt ist dabei der Abstand zwischen Wälzkreis 7 und Fußkreis 6 des Außenrades 1 sowie zwischen Wälzkreis 8 und Kopfkreis 9 des Innenrades 3 mindestens zweimal so groß wie der Abstand zwischen dem Wälzkreis 7 und dem Kopfkreis 5 beim Außenrad 1 bzw. der Abstand zwischen dem Wälzkreis 8 und dem Grundkreis 10 des Innenrades, wobei das Verhältnis der Abmessungen zwischen den beiden Zahnabschnitten 15 und 16 vorzugsweise einen Wert zwischen 3,5 : 1 und 5 : 1 aufweist.The outer wheel 1 has an internal toothing 2, in which the inner wheel 3 meshes with its external toothing 4. Compared to the fixed outer gear 1, the inner wheel 3 rotating in the direction of arrow 24 moves in the direction of arrow 23. The pitch circle 7 of the outer wheel, like the pitch circle 8 of the inner wheel 3, is oriented in the direction of the tooth height 14 and the center points 17 and 25 of the pitch circles the center points 17 and 25 shifted, whereby a small section 16 of the teeth 2 and 4 and a much larger section 15 are formed, both of which complement each other to the tooth height 14 which is practically the same for both wheels 1 and 3. The distance between pitch circle 7 and root circle 6 of outer wheel 1 and between pitch circle 8 and tip circle 9 of inner wheel 3 is preferably at least twice the distance between pitch circle 7 and tip circle 5 for outer wheel 1 or the distance between pitch circle 8 and the base circle 10 of the inner wheel, the ratio of the dimensions between the two tooth sections 15 and 16 preferably having a value between 3.5: 1 and 5: 1.

Die durch den Wälzpunkt 12 und den Schnittpunkt 13 der Kopfkreise 5 und 9 verlaufende Eingriffslinie 11 liegt auf einem Kreis mit dem Radius 26, der vom Kreismittelpunkt 19 ausgeht. Wälzt das Innenrad auf dem stillstehenden Hohlrad ab, so beschreibt der Krümmungsmittelpunkt 19 einen zum Wälzkreis 7 des Außenrades konzentrischen Kreis 18. Die Verbindungsgerade 21 zwischen dem Mittelpunkt des Hohlrades 17 und dem jeweiligen Wälzpunkt 12 schneidet diesen Kreis im momentanen Krümmungsmittelpunkt. Der Radius des Kreises 18 ist durch die angegebenen Bedingungen festgelegt. Die dabei sich ergebende Verzahnungsform löst die gestellte Aufgabe in hervorragender Weise.The line of engagement 11 extending through the pitch point 12 and the intersection 13 of the tip circles 5 and 9 lies on a circle with the radius 26 which starts from the center point 19 of the circle. If the inner wheel rolls on the stationary ring gear, the center of curvature 19 describes a circle 18 which is concentric with the pitch circle 7 of the outer wheel. The straight line 21 between the center of the ring gear 17 and the respective pitch point 12 intersects this circle at the current center of curvature. The radius of the circle 18 is determined by the specified conditions. The resulting form of gearing solves the task in an outstanding manner.

Claims (3)

1. An internal combustion engine having a lubricating-oil pump and a lubricating-oil channel (56)
characterized in that
the lubricating-oil pump is an internal gear pump in which the set of teeth is so designed that the tooth flanks are in mesh on essentially all of the teeth which are lying between the points (13) of intersection of the crown circles (5, 9) and form delivery cells which are hydraulically tight with respect to one another,
where at least the delivery cells of larger volume are closed off with respect to the lubricating to the lubricating-oil (56) by an non-return valve (54) in each case,
and that the suction channel (35) to the lubricating-oil pump a fixed choke (37) is seated, which is bypassed by a bypass channel (38) with a pressure-controlled valve (39) when the pressure in the delivery channel lies below a threshold value.
2. An internal combustion engine as in Claim 1, characterized in that
pressure-controlled valve (39) exhibits a pressure- control chamber (43) which opens to the sump (36) upon a maximum permissible pressure being exceeded.
3. An internal combustion engine as in Claim 1 or 2,
characterized in that the inlet (35) to the lubricating-oil pump is connected to an unthrottled inlet channel (58) which for covering a particularly high lubricating oil consumption is opened or closed by an electromagnetically actuated valve (59).
EP86902794A 1985-05-09 1986-05-06 Variable capacity pump Expired EP0225338B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3516718 1985-05-09
DE3516718 1985-05-09

Publications (2)

Publication Number Publication Date
EP0225338A1 EP0225338A1 (en) 1987-06-16
EP0225338B1 true EP0225338B1 (en) 1989-10-25

Family

ID=6270274

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86902794A Expired EP0225338B1 (en) 1985-05-09 1986-05-06 Variable capacity pump

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US (1) US4750867A (en)
EP (1) EP0225338B1 (en)
JP (1) JP2598396B2 (en)
DE (1) DE3666606D1 (en)
WO (1) WO1986006797A2 (en)

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Also Published As

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JP2598396B2 (en) 1997-04-09
JPS63500112A (en) 1988-01-14
DE3666606D1 (en) 1989-11-30
WO1986006797A2 (en) 1986-11-20
US4750867A (en) 1988-06-14
EP0225338A1 (en) 1987-06-16

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