DE3606342A1 - Periodically operating pump with an adjustable displacement volume - Google Patents

Abstract

In these periodically operating pumps, the displacement volume is capable of infinite variation, either arbitrary or under the control of the pressure difference of the pumped substance, between a minimum, which maybe zero, and a maximum predetermined by the size of the pump, this being achieved by displacement, parallel to the axis of rotation, of parts delimiting the delivery space or delivery spaces. Since the pumps do not require any inlet and outlet valves and are of symmetrical construction as regards their functioning, the direction of flow of the pumped substance is dependent on the direction of running of the pump; it is, therefore, also possible, in general, for them to be set in motion by the pumped substance flowing through them under pressure, the direction being dependent on the pumped substance. These characteristics offer the possibility of using pumps of this kind as closed systems for the construction of power-transmitting and continuously variable transmissions with any desired frequency transmission range and of giving them variable special characteristics. By means of valves which separate the substance-filled spaces between the pumps from a reservoir for the said substance, the pumps can be disconnected; retardation processes can be performed by throttle valves.

Description

Regarding claim 1: These periodically operating pumps are pumps which are designed in accordance with this invention in such a way that the stroke volume, defined as the volume delivered during a full revolution of the drive shaft ( NW ), is steplessly between a minimum, which can also be zero, and can be set to a maximum - predetermined by the pump size. For this purpose, the housing part delimiting the delivery space or the delivery areas is divided in such a way - possibly several times - and these parts are in turn, even with rotating parts, combined to form a fixed pump part ( FP ) and a movable pump part ( VP ) that shift the displaceable pump part ( VP ), the effective length of the working rotor ( AR ) or the working rotors ( AR ) and thus the stroke volume, by means of a control rod ( ES ) parallel to the axis of rotation of the drive shaft ( NW ) against the fixed pump part ( FP ) leaves.

Depending on the basic design of the pump - for example single or multi-shaft, with a circular cylindrical or other shaped bore, with or without a gate valve - the division of the housing part of the pumps that delimits the pumping chamber or pumps and the combination of parts to form the fixed pump part ( FP ) and the movable pump part ( VP ) can be made differently. The inflow opening ( SE ) and the outflow opening ( WÖ ) are to be placed in such a way that they only connect with increasing or decreasing delivery spaces with each stroke volume setting . In order to keep leakages in the additional gap spaces between mutually movable surfaces small, these surfaces must be sufficiently large in the direction of the pressure gradient of the conveying substance and their edges pointing in the conveying chambers must be chosen as small as possible; in addition, some sealing elements can be installed.

In the following, the end wall with the end wall ( ST 1 ) belonging to the fixed pump part ( FP ), if it rotatably receives the working rotor ( AR ) as a whole, with the sleeve ( H 1 ), the end wall ( ST ) assigned to the movable pump part ( VP ) 2 ) or correspondingly designated sleeve ( H 2 ).

• A) Single-shaft pumps
  In the case of single-shaft pumps such as rotary lobe pumps, cell pumps and similar rotary displacement pumps, the effective length of the working rotor ( AR ) and thus the stroke volume are changed in that 1. the correspondingly hollowed out and rotatable end wall as a sleeve ( H 2 ) is liquid-tight in the circular cylindrical bore of the pump above the immovable working rotor ( AR ) is displaced parallel to its axis of rotation or that 2. the displaceable working rotor ( AR ) is displaced parallel to the axis in the correspondingly hollowed out and rotatable as a sleeve ( H 1 ) end wall; in this second case, the front wall ( ST 2 ) with the working rotor ( AR ) must be moved in the not necessarily round hole in a manner that is impermeable to the liquid. Elements such as gate valves ( SS ) that periodically slide in grooves in the housing or working rotor ( AR ) must be parallel to the axis of rotation of the working rotor ( AR ) in slots ( SL ) in the end wall ( ST 1 ) or sleeve ( H 1 ). immersed in a slidable manner without interrupting their periodic sliding. (See example 1.)
• B) Multi-shaft pumps
  In the case of multi-shaft pumps such as rotary lobe pumps and gear pumps with two or more working rotors ( AR ), the division of the housing part delimiting the delivery space or the delivery areas and the combination of individual parts to form the fixed pump part ( FP ) and the movable pump part ( VP ) must be carried out from the following points of view:
  Two interlocking working rotors ( AR ) must be axially parallel to each other, possibly by a screwing movement - for example with helical teeth on a gear pump -; one of them is assigned to the fixed pump part ( FP ), the other to the movable pump part ( VP ).
  Portions of the working rotors ( AR ) protruding beyond the axis-parallel contact distance must be able to immerse themselves in sleeves ( H ) rotating with them in a manner that is impermeable to the conveying substance, each of which is mounted in the end wall of the fixed pump part ( FP ) or the displaceable pump part ( VP ) to which the associated working rotor ( AR ) is not assigned. In the case of hollow working rotors ( AR ) such as internally toothed gears, instead of sleeves ( H ), solid bodies that can be inserted into them ( VL ) must be inserted in a manner that is impermeable to the substance of the substance.
  A side wall ( SW ) parallel to the axes of rotation of the working rotors ( AR ) then belongs to the displaceable pump part ( VP ) if the working rotor ( AR ) attached to it belongs to the fixed pump part ( FP ) and the sleeve ( H 2 ) into which it immersed when moving the movable pump part ( VP ), has a larger outer diameter than it.
  The stroke volume is in turn adjusted in that the displaceable pump part ( VP ) is displaced parallel to the axis of rotation against the fixed pump part ( FP ), which changes the mutual contact distance of interlocking working rotors ( AR ) and thus the stroke volume of the pump; at the same time, the protruding portion of the working rotors ( AR ) is immersed in the sleeves ( H ) rotating with them, or is filled with hollow working rotors ( AR ) by insertable full bodies ( VL ).
  If the stroke volume can be reduced to zero, the working rotors ( AR ) must be driven synchronously outside the actual pumping station by synchronous gearwheels ( Z ). (See example 2.)

Depending on the basic design of the pump, working rotors ( AR ) can also be replaced by control rotors ( SR ).

A system of such pumps - with as little pulsation as possible - then forms a continuously switchable and force-transmitting gear with an arbitrarily specified frequency translation range if the flow of the pumped substance is self-contained in series and / or parallel, i.e. if the pumped substance pumps in series and / or flows in parallel without a short circuit, and at least one pump can be driven by a motor, for example. These externally driven pumps are called drive pumps ( NP ), pumps driven by the flow of the pumped substance are driven pumps ( BP ). These terms are retained even if the transmission transmits power in the opposite direction, for example braking. Valves ( V ) that can be opened from the outside and through which the spaces ( R ) between the pumps filled with pumped substance can be relieved to a pumped substance reservoir ( FR ) take on the coupling function. At a constant drive frequency, the frequency of the output pump (s) ( BP ) increases when the stroke volume of the drive pump (s) ( NP ) is increased and / or its own is reduced; if the stroke volume is reversed, the frequency of the output pump (s) ( BP ) drops. The infinitely variable switchability of such a transmission results from the infinitely variable variability of the stroke volume of the pumps used, the arbitrary frequency translation range from the possibility of using pumps whose stroke volume can be arbitrarily small. If at least two output pumps ( BP ) are connected in parallel in the material flow, they have the properties of a differential gear. This can be blocked, for example, by mechanically reversibly connecting the shafts of these output pumps ( BP ) to one another. The construction of differential gears with a lock and additionally continuously switchable frequency transmission ratio of the output pumps ( BP ) is also possible through the use of twin or multiple pumps according to claim 2. (See in this description under "Claim 2".)

If several output pumps ( BP ) are connected in series in the material flow and if the stroke volume setting is not fixed for one or more of them, these output pumps ( BP ) are (are) moved with a frequency that fluctuates to a greater extent than idler pumps. By fixing their stroke volume, they can be switched on for power transmission at a selectable frequency.

The changes in the volume of the interior of such a transmission filled with pumped substance and any leakage losses resulting from changes in the displacement of individual pumps of the gear unit and any leakage losses can be compensated for as follows: Since all spaces ( R ) filled with pumped substance between the pumps are never under pressure at the same time, over between these rooms ( R ) and the conveying substance reservoir ( FR ) built-in valves ( V ) - the valves ( V ) with coupling function can be included - which, if the allocated space ( R ) between pumps has no pressure, are under pressure by redirected conveying substance Rooms ( R ) between pumps are opened hydraulically, and the pumped substance flows in or out as required. (See example 3.)

Regarding claim 2: twin pumps - and correspondingly multiple pumps - according to claim 2, this invention is obtained according to the invention if two pumps according to claim 1 have a common shaft or if they are driven in a fixed frequency ratio. If these pumps draw material from a common inflow, the strength of the separate outflow of the individual pumps can be set to any ratio by separately changing the stroke volume of the individual pumps. Conveying substance streams that can be divided in this way can therefore achieve a continuously adjustable frequency ratio in systems of pumps designed as gearboxes on output pumps ( BP ) connected in the conveying substance streams.

If a twin pump is used as the drive pump ( NP ) and if only one of its individual pumps is used for stepless frequency switching, while the stroke volume setting of the second individual pump is not fixed, then its separate feed substance flows can be directed to two output pumps ( BP 1 ) and ( BP 2 ), which then have the properties of a differential gear on their output shafts ( BW 1 ) and ( BW 2 ), their (varying) frequency ratio forcing the displacement setting of the non-fixed single pump of the twin pump. This differential gear can be locked in that the previously unfixed stroke volume setting of the second individual pump is synchronized with the first pump. By separately setting the stroke volume of the two individual pumps of the twin pump, the frequency ratio of the two output pumps ( BP 1 ) and ( BP 2 ) can be set as desired.

If multiple pumps are used instead of twin pumps, differential gears can be built with correspondingly more output pumps ( BP ), which can be blocked or set in a desired frequency ratio.

Regarding claim 3: The self-control of a pump according to claim 1, which is required in this claim, whereby a reasonable law must be specified - that, for example, the increase in the pressure difference of the conveying substance between the outflow side and the inflow side leads to a reduction in its stroke volume - can be carried out in accordance with this invention Realize the installation of additional parts: Of two pistons playing in the fixed pump part ( FP ) parallel to the axis of rotation of the working rotor (s) ( AR ), which are connected to the movable pump part ( VP ), the leads as Pressure pistons ( DK ) designated pistons to reduce the stroke volume of the pump when the content in its cylinder, the pressure cylinder ( DZ ), is increased, which is referred to as suction piston ( SK ), when the content in its cylinder, the suction cylinder ( SZ ) is reduced. For this purpose, the inflow and outflow sides of the pump to the pressure cylinder ( DZ ) and the suction cylinder ( SZ ) have connections through the substance which each contain a check valve ( RV ), namely a positive pressure difference between the outflow side and the inflow side opens the check valve ( RV ) between Inflow side and suction cylinder ( SZ ) and that between the outflow side and pressure cylinder ( DZ ) and closes the other two check valves ( RV ). The linear actuating force then caused by the pressure difference of the conveying substance via the pressure piston ( DK ) and the suction piston ( SK ) is counteracted by a linear restoring force which increases the stroke volume, for example in the form of a spring. The restoring force and the cross-sectional area of the suction piston ( SK ) and the pressure piston ( DK ) must be adjusted to the specified law, taking into account the suction and pressure forces of the pumping substance that contribute to the change in stroke volume inside the pump. (See example 4.)

According to this principle, the effort required to change the stroke volume in a pump according to claim 1 can be reduced to a minimum: by appropriate size of the cross-sectional area of the suction piston ( SK ) and the pressure piston ( DK ), the suction contributing to the stroke volume change inside the pump - and pressure forces of the substance removed; the restoring force is eliminated.

Pumps can also be built according to the principle described, the stroke volume of which is increased by increasing the pressure difference between the outflow side and the inflow side and in which a restoring force leads to a reduction in the stroke volume. If such pumps are used as drive pumps ( BP ) in transmission construction and the first described, whose stroke volume is reduced as a drive pump ( NP ) due to an increasing pressure difference between the outflow side and inflow side, self-switching gearboxes are obtained, provided the actuating and restoring forces are adjusted to a specified law are. The number of actuating and resetting elements can be reduced by mechanically coupling the pumps to one another.

Regarding claim 4: If, in a system of pumps designed as a gearbox, the conveying substance flow is reduced by gradually closing throttle valves ( DR ) between the output pump (s) ( BP ) and the drive pump (s) ( NP ), this inevitably leads to a drop in frequency and finally a standstill of the pumps in the flow of the pumped material. It makes sense to build the throttle valves ( DR ) in the direction of flow of the substance flow behind the output pump (s) ( BP ) and in front of the valves ( V ) with coupling function and / or substance compensation function.

Pumps with a continuously adjustable stroke volume are known, namely radial piston pumps, axial piston pumps and cell pumps ("Pumps for liquids", Prof. Dipl.-Ing. Pohlenz, VEB Verlag Technik, Berlin 1984, pages 63 ff. And 119 ff.).

All of these pumps - some of them many - periodically parts moved back and forth, and movements that change the stroke volume lead, are complicated or take hold of that Angular momentum on or shift axes of rotation of rotors vertically to their direction, making them unsuitable for permanent switching are.

For pumps with a continuously adjustable stroke volume this invention, a linear is sufficient to change the stroke volume Movement parallel to the drive shaft; multi-shaft pumps also do not need periodically reciprocated parts. Therefore, these pumps can be operated with little technical and material effort to infinitely switchable and power-transmitting Assemble different types of transmission systems, which additionally with integrated wear and maintenance-free clutch and brake can be equipped.

Embodiments

Preliminary remark: The following are common to the examples Drawings cavities left white, fixed and non-rotatable parts hatched almost vertically, fixed however, rotating parts are dashed almost vertically, movable but not rotatable parts almost horizontally hatched and movable and at the same time rotatable parts dashed almost horizontally. Seals, bearings and design-related Disassembly into individual parts is not shown and not mentioned in the descriptive text.

1. Example: Rotary piston pump with a working rotor and a gate valve

In this rotary piston pump with an almost elliptical cylindrical working rotor (AR), which rotates in a circular-cylindrical bore, and with a locking slide (SS), which lie close together in a groove in the housing wall between the inlet aperture (SE) and the outflow opening (WÖ) , slides perpendicularly to the working rotor ( AR ) and parallel to its axis of rotation, only the end wall designed as a sleeve ( H 2 ) belongs, which rotates with the working rotor ( AR ) and can be displaced in a substance-tight manner parallel to its axis of rotation, and the locking slide ( SS ) to the movable pump part ( VP ). The groove ( NU ) for the gate valve ( SS ) merges into the slot ( SL ) of the end wall ( ST 1 ). The shift rod ( ES ) is rotatably mounted in the bottom of the sleeve ( H 2 ).

Fig. 1 shows a section of this pump through the axis of rotation of the working rotor ( AR ) and through the largest area of the gate valve ( SS ), the connection of which is via a long arm, the angled end of which is in a circular groove ( KN ) in the bottom of the sleeve ( H 2 ) hangs, its movability with the sleeve ( H 2 ) guaranteed.

Fig. 2 shows a section on which the axis of rotation of the working rotor ( AR ) is perpendicular, near the end wall ( ST 1 ), so that the inlet opening ( SE ) and the outlet opening ( WÖ ) are met.

2. Example: Two-part gear pump with steplessly between Zero and a maximum adjustable stroke volume

The delivery chamber of a gear pump, the rotors, working rotors ( AR 1 ) and ( AR 2 ), when rotating its two identical circular cylindrical and parallel aligned rotatably and with parallel to their axes ( A 1 ) and ( A 2 ) aligned and interlocking toothed racks , with a tight wall closure, the liquid from the inflow side to the outflow side is divided in such a way that it can be moved continuously between zero and by moving the movable pump part ( VP ) parallel to the axes ( A 1 ) and ( A 2 ) against the fixed pump part ( FP ) its maximum extent can be changed, which leads to a corresponding change in stroke volume. To prevent further displacement in the extreme positions, the movable pump part ( VP ) is blocked by the stops ( ASR ) at zero stroke volume and by the stops ( ASL ) at maximum stroke volume. In order to guarantee a synchronous rotation of the working rotors ( AR 1 ) and AR 2 ) at zero stroke volume, the width is adjusted outside the delivery area by the maximum displacement distance of the movable pump part ( VP ) and with the axes ( A 1 ) and ( A 2 ) fixedly connected synchronous gears ( Z 1 ) and ( Z 2 ) the rotation transmission from the driven axle ( A 1 ) to the axle ( A 2 ).

In this pump, the displaceable pump part (VP) 1 includes the axis (A 2) with the working rotor (AR 2) and the timing gear (Z 2), 2. the working rotor (AR 2) circular cylinder-like adjacent side wall (SW 1), 3. the end wall ( ST 2 ), that is one of the walls that delimit the conveying space perpendicular to the axes ( A 1 ) and ( A 2 ), 4. the axis in this end wall ( ST 2 ) together with the working rotor ( AR 1 ) rotatably mounted and externally circular cylindrical sleeve ( H 1 ), which can be moved over the working rotor ( AR 1 ) by means of toothed ridges protruding into its lumen, and 5. the shift rod ( ES ), which leaves the housing and serves to adjust the displacement. The fixed pump part ( FP ) connected to the housing includes 1. the axis ( A 1 ) with the working rotor ( A 1 ) and the synchronous gear ( Z 1 ), which extends the housing as a drive shaft ( NW ), 2. which leaves the housing Working rotor ( AR 2 ) side wall ( SW 2 ) in the form of a circular cylinder as a housing part, 3. the other end wall ( ST 1 ) and 4. the sleeve in this end wall ( ST 1 ) that is rotatably mounted axially together with the working rotor ( AR 2 ) and has a circular cylindrical outside ( H 2 ), in which the working rotor ( AR 2 ) can be moved in a substance-tight manner by means of toothed ridges protruding into its lumen.

Fig. 3 shows in the axes (A 1) and (A 2) spanned planes a section through such a pump. The working rotor ( AR 1 ) and the synchronous gearwheel ( Z 1 ) are hit by the ridges of toothed racks, the working rotor ( AR 2 ) and the synchronizing gearwheel ( Z 2 ) by valleys between toothed strips; the opposite applies to the sleeves ( H 1 ) and ( H 2 ). Since the working rotor (AR 2) with a sufficient length also remains in maximum Hubvolumeneinstellung in the sleeve (H 2), he needs at this - in Figure 3, right -. The end not to be stored separately. Parallel to the axis ( A 1 ), which is extended as the drive shaft ( NW ), is the shift rod ( ES ) connected to the displaceable pump part ( VP ) and intended for adjusting the displacement, which, like that, leaves the housing and is not shown here. The arrows provided with the numbers 4 to 7 on the lower edge of this figure mark in this order the steps of FIGS. 4 to 7 which are perpendicular to the axes ( A 1 ) and ( A 2 ) and which are from left in relation to FIG. 3 are to be considered. Since the flow direction of the pumping substance reverses with the direction of rotation of the pump, clockwise rotation of the working rotor ( AR 1 ) is assumed when looking from the direction of the drive shaft ( NW ) in order to be able to define the inflow and outflow side.

FIG. 4 shows a mirror image of a section as a top view of the wall delimiting the delivery space - on the left in FIG. 3.

FIGS. 5 and 6 cut the pumping chamber, Fig. 6 in the height close to the end wall-mounted inflow opening (ST 1) (SE) and a drain aperture (WÖ).

Fig. 7 represents a section in supervision of the fixed end wall ( ST 1 ) and the front of the immovable sleeve ( H 2 ).

3. Example: Power transmission and continuously switchable Gearbox with a predefined frequency range and integrated Coupling that has the characteristics of a differential owns

The gearbox consists of three gear pumps, as shown in Example 2. Two of the pumps, called output pumps ( BP 1 ) and ( BP 2 ), are identical in terms of the delivery chamber; they differ only in that the axles ( A 1 ), which are extended as output shafts ( BW 1 ) and ( BW 2 ), the housing for the output pump ( BP 1 ) on the side of the sleeve ( H 1 ), for the output pump ( BP 2 ) on the side of the front wall ( ST 1 ). The delivery chamber of the third pump, called the drive pump ( NP ), is to be adjusted in size to the desired frequency translation range of the driven pumps ( BP 1 ) and ( BP 2 ), but the distance over which the movable pump part ( VP ) can be moved all three pumps should be of the same length. The stroke volume zero is not achieved with any pump, consequently there are no synchronous gears. The three pumps are aligned with their axes ( A 1 ) and ( A 2 ) in parallel in one plane, in a common housing that also serves as a fluid reservoir ( FR ), and their movable pump parts ( VP ) are in one block ( B ) connected, the stroke volumes of the output pumps ( BP 1 ) and ( BP 2 ) being of the same size in each position and, by shifting the block ( B ) through the shift rod ( ES ) connected to it, reversed as the stroke volume of the drive pump ( NP ) change. The pumped substance discharged from the drive pump ( NP ) on the outlet side is pressed via a V-shaped cavity, space ( R 1 ), from its own inflow side in parallel through the output pumps ( BP 1 ) and ( BP 2 ), in which, thereby, in Movement set, the force on the output shafts ( BW 1 ) and ( BW 2 ) can be removed. From here, the substance to be conveyed is again routed via a V-shaped cavity, space ( R 2 ), to the inflow side of the drive pump, thus closing the substance-to-substance cycle. A valve ( V 1 ) and ( V 2 ) is installed in the wall ( W ) of each of the rooms ( R 1 ) and ( R 2 ) towards the liquid substance reservoir ( FR ). The valve ( V 1 ) is kept closed by the pressure of the liquid in the room ( R 1 ). If the fluid pressure drops here with simultaneous pressure increase in room ( R 2 ) or a negative pressure is created - rooms ( R 1 ) and ( R 2 ) are never under pressure when the power is transmitted - valve ( V 1 ) becomes pressurized of conveying substance diverted via the pipe ( RO 1 ) from the space ( R 2 ) to a valve piston ( VK 1 ) that plays in a valve substance-tight manner in a valve cylinder ( VZ 1 ), so that conveying substance between the space ( R 1 ) and the conveying substance reservoir ( FR ) needs, leakage losses or volume changes in the delivery areas of the three pumps can be compensated for by inflows or outflows. The valve ( V 2 ), which is equipped like the valve ( V 1 ), performs the analogous function with reversed pressure behavior in rooms ( R 1 ) and ( R 2 ). If the valves ( V 1 ) and ( V 2 ) are opened from the outside at the same time, for example via a lever mechanism, which is not shown, the flow of material is short-circuited and the three pumps are thus uncoupled. If the frequency of the drive pump ( NP ) is constant, the sum of the frequencies of the output pumps ( BP 1 ) and ( BP 2 ) is minimal if the block ( B ) is placed over the control rod ( ES ) so that the stroke volume of the drive pump ( NP ) is minimal and the output pumps ( BP 1 ) and ( BP 2 ) are maximum; the maximum is at the other extreme setting. This gearbox has the properties of a differential gear, since the flow of the conveying substance adapts to the frequency ratio of the output pumps ( BP 1 ) and ( BP 2 ).

This gear unit corresponds to a conventional one Road vehicle with two-wheel drive of the clutch, the manual transmission without reverse gear, which is steplessly switchable here and the differential.

A self-switching which is dependent on the conveying substance pressure and which increases the sum of the frequencies of the driven pumps ( BP 1 ) and ( BP 2 ) and vice versa when the conveying substance pressure falls in the room ( R 1 ), and vice versa, is obtained in that in addition to a suitable spring constant and under a suitable preload built-in spring, which moves the block ( B ) and reduces the stroke volume of the output pumps ( BP 1 ) and ( BP 2 ), the sum of the area parts of the displaceable pump part that are exposed to the fluid pressure perpendicular to the axes ( A 1 ) and ( A 2 ) ( VP ) of the output pumps ( BP 1 ) and ( BP 2 ) are chosen to be larger than the corresponding area proportions of the drive pump ( NP ), in each case on the side of the room ( R 1 ). Braking use of the gearbox requires the same on the side of the room ( R 2 ).

Fig. 8 shows in the planes spanned by the axes ( A 1 ) and ( A 2 ) of all pumps a section through such a transmission, in which the drive pump ( NP ) is installed between the driven pumps ( BP 1 ) and ( BP 2 ) . The three circles (K) on portions of the contact paths of the working rotors (AR 1) and (AR 2) the placement of the inlet openings (SE) and outlet openings (WÖ) indicate the three pump above and below the paper layers as a connection to the rooms (R 1 ) and ( R 2 ). The pipes ( RO 1 ) and ( RO 2 ) are the lines for the conveying substance between the space ( R 2 ) and the valve cylinder ( VZ 1 ) or the space ( R 1 ) and the valve cylinder ( VZ 2 ).

FIG. 9 shows a sectional view perpendicular to FIG. 8, in which the axes ( A 2 ) of the three pumps lie. The block ( B ) of the displaceable pump parts ( VP ) is held together between the output pump ( BP 1 ) and the drive pump ( NP ) via the pair of brackets ( BÜ ), which is attached to the piston-like extensions of the end walls ( ST 2 ); to the output pump ( BP 2 ) consists of the drive pump ( NP ) by directly connecting the piston-like extensions of the end walls ( ST 2 ) of cohesion. The side walls ( SW 2 ) of the output pumps ( BP 1 ) and ( BP 2 ) go in front of the paper plane, those of the drive pump ( NP ) behind it into the housing. At the output pumps ( BP 1 ) and ( BP 2 ) they open into the housing on the left side and into the end wall ( ST 1 ) on the right side behind the paper level; in the case of the drive pump, this is done by swapping the right and left in front of the paper plane (see also Figs. 4 to 7). The elliptical structures between the housing and the pair of brackets ( BÜ ) are the obliquely cut legs of the V-shaped spaces ( R 1 ) and ( R 2 ).

Fig. 10 shows the space ( R 2 ) analogous space ( R 1 ) on average parallel to Fig. 8. The conveyed substance ejected approximately in the middle of the image on the downstream side of the drive pump ( NP ) is distributed in the two V-shaped legs of the Room ( R 1 ) on the inflow side to the output pumps ( BP 1 ) and ( BP 2 ). The valve ( V 1 ) is embedded in the wall ( W ), next to it is the connection for the pipe ( RO 2 ) which leads to the valve cylinder ( VZ 2 ).

Fig. 11 shows in a larger scale the needed for volume compensation of the feed material between the gearbox interior and the delivery substance reservoir (FR), the space (R 1) built into the wall (W) valve (V 1) in the open state in section. Its head has in the space (R 1), its shank (VS 1) bears in the valve cylinder (VZ 1) the valve piston (CV 1) and breaks through the bottom of the valve cylinder (VZ 1) so that it simultaneously via an unillustrated mechanical leverage can be opened with the valve ( V 2 ) to decouple the gearbox. On the side of the liquid substance reservoir ( FR ), the valve cylinder ( VZ 1 ) must not be attached to the wall ( W ) with its entire circumference, but must have through openings ( DÖ ) so that the liquid substance can be equalized as required. The pipe ( RO 1 ) leads from the space ( 2 ) the pressurized liquid to open the valve ( V 1 ) into the valve cylinder ( VZ 1 ). The opening ( Ö ) on the valve cylinder ( VZ 1 ) ensures that the valve piston ( VK 1 ) can play freely.

4. Example: Two-part gear pump with continuously variable itself adjustable stroke volume depending on pressure

The minimum stroke volume of this pump is greater than zero, so no synchronous gears ( Z ) are required; their inflow always takes place under the same pressure conditions, so there is no need for a suction cylinder ( SZ ) and suction piston ( SK ). In principle, this pump is constructed like that in the second example. Between the housing and the front part of the movable pump part ( VP ) the helical spring ( SF ) pulls the stroke volume of the pump in maximum position. In the pressure cylinder ( DZ ) starting from the housing wall, the pressure piston ( DK ) plays parallel to the direction of the axes ( A 1 ) and ( A 2 ) and is connected to the piston-like extension of the end wall ( ST 2 ) via the switching rod ( ES ). If conveying substance reaches the pressure cylinder ( DZ ) from the discharge side of the pump through the cylinder opening ( ZÖ ) via a line (not shown), the actuating force now exerted via the pressure piston ( DK ) counteracts the reduction in the lifting volume of the coil spring ( SF ).

Fig. 12 shows a section through such a pump in the plane spanned by the axes ( A 1 ) and ( A 2 ).

Fig. 13 shows with flap-like check valves ( RV ) the circuit diagram when the pressure difference of the pumping substance between the discharge side and the inflow side is used to adjust the stroke volume of the pump.

• List of reference symbols A : axis
  AR : working rotor
  ASL : stop to block the maximum stroke volume
  ASR : Stop for blocking the minimum stroke volume
  B : Block of the movable pump parts ( VP ) of several pumps
  BP : output pump
  BÜ : Pair of temples
  BW : output shaft
  DK : pressure piston
  DÖ : passage opening
  DR : throttle valve
  DZ : impression cylinder
  ES : shift rod
  FP : fixed pump part
  FR : conveyor substance reservoir
  G : housing
  H : sleeve
  K : Circle
  KN : circular groove
  NP : drive pump
  NW : drive shaft
  Ö : Opening on a valve cylinder
  R : room
  RV : check valve
  SF : coil spring
  SK : suction piston
  SL : slot
  SE : inflow opening
  SR : control rotor
  SS : gate valve
  ST : front wall
  SW : side wall
  SZ : suction cylinder
  V : valve
  VK : valve piston
  VL : full body
  VP : movable pump part
  VS : valve stem
  VZ : valve cylinder
  W : wall
  WÖ : drain opening
  Z : synchronous gear
  ZÖ : cylinder opening
  1 appended to a reference number for a pump: belonging to ( FP ), a gearbox: the number of the pump
  2 appended to a reference number for a pump: belonging to ( VP ), a gearbox: the number of the pump

Claims (4)

1. Periodically operating pumps with adjustable stroke volume, in particular rotary displacement pumps, characterized in that the stroke volume, defined as the volume delivered during a full revolution of the drive shaft, is infinitely variable by moving the delivery space or parts delimiting the delivery spaces parallel to the axis of rotation of the drive shaft can be set between a minimum and a maximum and that, unaffected by this, the flow direction of the pumping substance reverses with the running direction of the pump, so that pumps whose pumping material flow never drops to zero, except when the pump is at a standstill, depending on the direction of one of them under pressure flowing substance flow in motion. On the basis of these properties, systems can be built with a self-contained pumping material flow, also mixed with pumps with a fixed stroke volume, in series and / or in parallel with such pumps, the continuously switchable and force-transmitting gearboxes with any given frequency translation range and, when pumps in parallel are connected Conveying substance flow with the properties of differential gears that can be coupled and uncoupled via valves. When pumps are connected in series in the conveying substance flow, switchable idler pumps are possible as optional power consumers. 2. Pumps according to claim 1, characterized in that they designed as a twin or multiple pumps an inflowing Conveyor flow in any ratio that can be changed in two or more flowing substance flows split up. Therefore, when using such Twin or multiple pumps in gearboxes Systems of pumps differential gear with lock or additionally arbitrarily adjustable frequency ratio instead the property of the differential lock will. 3. Pumps according to claim 1, characterized in that itself  with them the stroke volume setting according to a sensible predetermined Lawfulness through the difference in the substance pressure between the inflow side and the outflow side itself controls what systems designed as a transmission with such Pumps built by the fluid pressure self-switching can be. 4. Systems of pumps designed as a transmission according to claim 1 to 3, characterized in that in the self-contained Conveyor flow built-in throttle valves brakes form appropriate energy converters.