CN112576487A

CN112576487A - In-line piston pump

Info

Publication number: CN112576487A
Application number: CN202011027025.2A
Authority: CN
Inventors: 伦纳德·盖斯勒
Original assignee: Liebherr Machines Bulle SA
Current assignee: Liebherr Machines Bulle SA
Priority date: 2019-09-25
Filing date: 2020-09-25
Publication date: 2021-03-30
Also published as: CN112576486A; CH716632A1; DE102020125021A1; DE102020125000A1; US20210088043A1

Abstract

The invention relates to an in-line piston pump, comprising: a drive shaft for driving the pump; at least two pistons which are operatively connected to the drive shaft and are arranged along the drive shaft axis and are each arranged so as to be able to reciprocate in a piston chamber; a suction connection for conducting the fluid to be pumped, wherein a valve is arranged in at least one, preferably in each piston chamber, in order to fluidically separate a suction channel, which is connected to the suction connection for the inflow of fluid during a compression movement of the respective piston, from the piston chamber. The pump is characterized in that a suction throttle valve is provided between the suction connection and the suction channel directly connected to the at least one valve, which suction throttle valve is arranged to be able to vary the volume flow of the fluid to be pumped between the suction connection and the suction channel.

Description

In-line piston pump

Technical Field

The present invention relates to an inline piston pump, preferably a hydraulic displacement pump of inline piston construction. The inline piston pump comprises at least two plunger units, which are arranged one after the other in the direction of the drive shaft axis.

Background

Such pumps are essential in most applications, for example for circulating the coolant of a motor vehicle, for the fan motor function, and for the oil circulation of an internal combustion engine. But also in small devices, such as small excavators.

DE 19708597 discloses a delivery pump of the intake-throttling type and shows the use of an intake-throttling for an inline piston pump.

Document WO 2010130495 a1 discloses an inline piston pump, the drive shaft of which is embodied as a crankshaft.

Thus, an inline piston pump with a camshaft is known from the prior art.

Disclosure of Invention

It is an object of the present invention to provide an in-line piston pump which is as cost-effective as possible and which offers a wide range of flexibility for assembly and thus a power density which is as high as possible. The invention is based on the object of providing a device for controlling and/or regulating an in-line piston pump, on the basis of which the fluid inflow to a plunger unit comprising a piston can be regulated in a simple manner.

This object is achieved by an in-line piston pump having all the features of claim 1. Such a pump has a structurally advantageous design and is designed to be space-optimized. Advantageous embodiments are specified in the dependent claims.

The inline piston pump of the present invention comprises: the pump comprises a drive shaft for driving, at least two pistons which are in active connection with the drive shaft and are respectively arranged in a reciprocating manner in a piston cavity, a suction connection for guiding a fluid to be pumped and a high-pressure connection for guiding the fluid to be pumped out. In addition, each of the at least two piston chambers of the inline piston pump of the present invention further comprises at least two valves, preferably implemented as check valves. When the first valve (hereinafter referred to as suction valve) is open, a fluid connection is created between the suction side and the piston chamber. When the second valve (hereinafter referred to as the high pressure check valve) is open, a fluid connection is created between the piston chamber and the high pressure side. Such a component assembly to be described next and at the same time also a functional assembly are referred to below as a plunger unit.

The suction valve is in this case in fluid connection with a space which can be varied in its volume by the piston and is intended, in a piston stroke, for the stroke to cause the space to become larger, into which, due to the low pressure, fluid can flow from the suction side of the in-line piston pump and, during the compression stroke of the piston, fluid which is not under pressure flows back to the suction side.

The high-pressure check valve is in this case in fluid connection with a space which can be varied by the piston in its volume and serves (i) to allow the compressed fluid to flow out in the direction of the high-pressure outlet during the compression stroke of the piston of the same plunger unit; (ii) in one piston stroke, which stroke causes the space to become larger, no fluid flows into the space from the high pressure side of the in-line piston pump; and (iii) during the compression stroke of the piston, fluid not under pressure in the other plunger unit flows back into the space.

In one embodiment of the inline piston pump of the invention, the fluid connection extends from the suction side through a suction channel, which can be commonly utilized by a plurality of plunger units. Alternatively or additionally, the in-line piston pump of the present invention has a fluid connection from the high pressure channel to a high pressure connection that may be commonly utilized by a plurality of plunger units.

In one variant, the inline piston pump of the invention has, between the suction connection and the suction channel which is directly fluidically connected to the at least one suction valve, a device which is arranged so as to be able to vary the volumetric flow of the fluid to be pumped between the suction connection and the suction channel. In a further variant, the device is in the immediate vicinity of the inline piston pump and is preferably integrated in the inline piston pump.

By means of the device arranged between the suction connection and the suction channel, which can be embodied as a suction throttle valve, the volume flow of the fluid to be pumped which leads to the at least one plunger unit can be adjusted in a simple manner. The suction throttle can be switched to a maximum throttle setting by setting the maximum opening (at which the fluid flows through the suction throttle with the lowest possible pressure loss). Preferably, in setting the maximum throttling, no complete constriction of the fluid connection occurs, but throttling, which ensures that there is still some fluid flow through to ensure self-lubrication of the in-line piston pump, however no volumetric fluid flow is provided for operating the consumer.

In a preferred embodiment of the invention, it can be provided that the adjustment of the height by throttling can be effected by the axial position of a correspondingly configured piston which is mounted axially displaceably in a correspondingly configured bore of the valve housing. In addition to this, the valve housing has corresponding recesses, by means of which fluid can be conducted from the intake connection to the piston (hereinafter referred to as valve piston) and to the intake channel.

In a particularly advantageous embodiment, the bore for introducing the valve piston into the valve housing provides a solution for the presence of a closing element which can be opened again after assembly and then closed again and again and can be accessed from the outside even when it is constructed completely together with an in-line piston pump.

Alternatively or additionally, the suction throttle valve is mounted in its assembled position in such a way that the longitudinal axis of the valve piston extends as far as possible parallel to the drive shaft axis.

The suction throttle valve is incorporated into the connection between the suction connection and the suction channel in such a way that the cross-section of the connection between the suction connection and the suction channel can be varied. The maximum connecting cross section is provided in the fully open position, so that for the rotational speed of the existing drive shaft, the maximum amount of fluid to be pumped can be sucked in by the in-line piston pump via at least one plunger unit, which is connected to the suction opening via the suction throttle. If the suction throttle valve is moved increasingly in the direction of the blocking position, a reduced amount of fluid to be pumped can be sucked in during this time by the at least one plunger unit.

According to an alternative variant of the invention, it can be provided that the movable valve piston has a flow region which is formed on the longitudinal axis of the piston by a section of narrowed diameter, in order to vary the degree of opening of the connection of the suction connection to the suction channel, wherein the flow region can preferably be configured as an annular space.

Furthermore, it can be provided according to the invention that the piston is a differential piston and has at least two longitudinal sections of different diameters, in one of which a flow region is arranged, wherein preferably the at least two longitudinal sections of different diameters are initially machined as separate blanks during the production process.

According to the invention, it is also possible to provide that at least two forces can act on the valve piston in the axial direction thereof, which forces are directed diametrically opposite. If there are only two forces, one of the forces facilitates movement or retention of the valve piston at the wider opening position, while the other force facilitates movement or retention of the valve piston at the smaller opening position.

In particular, one of the two forces is generated by a pressure spring on which the valve piston is supported. Here, an open end face of the longitudinal section with the larger diameter is preferably meant. In this case, it is also possible to achieve the total force by using a plurality of springs which generate respective forces on the valve piston which act in the same direction. It is not necessary here that all springs are pressure springs.

In this way, it is possible according to the invention to design the valve housing to have a corresponding bore via which a fluid connection to a control surface located on the valve piston is made possible, as a result of which a control pressure can be applied to the valve piston. Preferably, such control surfaces are located at the open end sides of the longitudinal sections with the smaller diameter. Alternatively or additionally, the control pressure is a pressure level which, in a fixed relationship to the high pressure level, is located on the high pressure connection of the inline piston pump or on the high pressure channel. Likewise, the control pressure can additionally provide a pressure level which is influenced externally from the high pressure level, i.e. the high pressure level which is reduced thereby. Furthermore, the control pressure directed by the inventive inline piston pump may be generated or provided from a further pressure source, thereby being at least initially independent of the high pressure level at which the inventive inline piston pump is located.

In a preferred embodiment of the invention, the valve piston has at least one control surface, which is oriented in such a way that the control pressure conducted there generates a force which opposes the restoring force of at least one spring on which the valve piston is supported.

In a preferred embodiment of the inline piston pump according to the invention, it can be provided that the longitudinal section of the valve piston provided with the flow region has a leakage channel extending in the direction of movement of the piston, so that leakage fluid resulting from the control pressure drilling can be discharged; at the same time, leakage fluid is drawn from the inner volume of the present piston bore, which is on the opposite side of the closure element. Such a leakage channel can thus also serve for damping the displacement movement of the valve piston.

Preferably, the suction throttle valve has at least one end abutment position and preferably two end abutment positions of the valve piston, whereby a maximum and/or minimum throttle can be defined reproducibly. In a preferred embodiment, the end of the spring opposite the valve piston interacts with a closing element of the piston bore, which comes into contact with the end serving as the displacement movement of the valve piston, wherein the closing element is preferably a locking bolt. Alternatively or additionally, the piston bore can have a step in the valve housing, which serves as a stop for the step of the valve piston.

According to a further alternative variant of the invention, it can be provided that the valve piston is equipped with springs which produce a force action which is permanent or only in a defined position region within the valve piston. In this case, it is also possible, with two springs, to generate forces in different respective axial directions when force-locking the valve piston.

The invention includes the presence of control surfaces of the valve piston, which can exert the same or different pressure levels and which can be oriented in the same or different directions.

Alternatively or additionally, it can be provided that the valve piston can be acted upon by at least one further generated force acting in the axial direction, for example by a servomotor, a proportional magnet, etc.

For this purpose, it can be provided that the drive shaft is embodied as a camshaft with a single-lobe cam or a multi-lobe cam, as a crankshaft or as an eccentric shaft.

In addition, it is possible to design the piston to be rotationally symmetrical with respect to the longitudinal axis. The piston may have a first section with a larger diameter having a constriction and a second section with a smaller diameter, the second section being spaced from the first section.

It is also possible to design the inline piston pump according to the invention with a plurality of openings, which also serve as high-pressure connections. In this case, it is possible to use one of the openings as a high-pressure connection, while the other openings are closed in a high-pressure-tight manner. Alternatively or additionally, it can be provided that the inline piston pump according to the invention has a plurality of openings, which can also be used as suction connections. In this case, it is possible to use one of the openings as a suction connection, while the other openings are closed in a pressure-tight manner.

An alternative variant of the method according to the invention can provide that the volume flows of the fluid to be pumped which are generated by the individual pistons are not completely or not at all coupled to one another downstream, but are discharged from the pump via at least two separate high-pressure outlets.

Typically, in case there are multiple high pressure outlets, these volume flows are fluidly connected to each other downstream of the plunger unit. This solution is advantageous for consumers that are connected to a plurality of high-voltage outlets, when two consumers are fluidically separated from each other on their high-voltage side. It is possible that the volume flows which have been separated from one another by a plurality of high-pressure connections are conducted as partial volume flows at the high-pressure inlets of the respective separate hydraulic consumers and/or switching valves, which can provide one of these partial volume flows or a sum of the volume flows based on these partial volume flows in a selectable manner at their outlets. Preferably, the selection of these partial volume flows (which are components of the sum of the volume flows) can be preset on the switching valve via a telemetric data exchange.

In the inventive inline piston pump, at least one channel separator is thus provided, which fluidically separates the associated outlets from one another in the high-pressure channel. Thus, a plurality of hydraulic consumers connected to the high-voltage outlet have their respective plunger units, the outlet volume flow or the hydraulic output power of which consumers may be dispensed with. In the case of directing individual partial volume flows to one switching valve, its high-pressure inlets each generate a volume flow through the respectively corresponding plunger unit.

Furthermore, according to a preferred variant of the invention, it can be provided that the volume flow of the fluid to be pumped generated by the individual plunger units is diverted downstream by at least one optionally provided channel separator, which is inserted into the high-pressure channel.

The channel separator can also be inserted when the inline piston pump unit is combined as needed, whereby the flexibility of use thereof is high.

According to the invention, it is possible to design at least two pistons to have different diameters. Through setting up a plurality of different diameters, can consider different with electrical apparatus according to the demand, connect on the high pressure outlet of the difference of pump with electrical apparatus. The bores containing the pistons can be adapted to the respective piston diameter, or for those bores with a larger diameter, a running sleeve can be provided for adapting to the piston diameter.

Alternatively or additionally to the use of such a channel separator, the inline piston pump of the invention can have in its basic structure downstream, with respect to the flow direction of the fluid to be pumped, a flow path which is separate from the inlet plunger unit, i.e. is sealed off from one another, up to the respective high-pressure outlet.

By combining the channel separation on the high-pressure side of the inline piston pump and the separate guidance of the partial volume flows at such a switching valve, it is achieved that the latter itself provides an output volume flow which is variable, with the possibility of different summation modes being present, which can be calculated from the partial volume flows, so that there is the possibility of a variable output volume flow (even with constant drive shaft rotational speed and constant device adjustment, by means of which the volume flow of the fluid to be pumped which can be guided to the at least one plunger unit is adjusted). Also here, the variability is limited to the selection possibilities between certain discrete values and the volume flow is not adjusted continuously; of course with relatively little expenditure. Finally, it is of course also possible to adjust the volume flow such that the in-line piston pump operates at constant rotational speed or can only operate at constant rotational speed, without operating the device in question or even without such a device (by means of which the volume flow that can be guided by the fluid to be pumped is adjusted on the suction side).

It can also be provided that the drive shaft is driven via a main drive, preferably an internal combustion engine or an electric motor, which is preferably connected to the drive shaft by a transmission.

According to a further alternative variant, it can be provided that a switching valve is provided which selectively connects at least two separate high-pressure outlets leaving the in-line piston pump to one another and, at the collective outlet, gives a volume flow generated by the connection or, at the two inlet sides, a partial volume flow which can be selectively conducted. In this way, a variable volume flow can be produced, which variability is still increased, since the volume flows of the at least two high-pressure outlets of the pump differ due to the different piston diameters of the respective plunger units. It will be appreciated by those skilled in the art that the present invention is not limited to two high pressure outlets and corresponding inlets on the on-off valve.

The invention also provides a method for controlling or regulating the in-line piston pump according to the invention, in particular the output volume flow, the power and the torque. It can be provided that the output volume flow can be varied as a function of the rotational speed of the drive shaft and/or the opening of the device, the intake on the suction side by the fluid to be pumped; and/or switching valves which enable a variable summation of the partial volume flows which can be produced in mutually separate units of the inline piston pump according to the invention.

In one variant of the method according to the invention for controlling or regulating an inline piston pump according to the invention (in particular output volume flow, power and torque), the regulating variable is variable as a function of the rotational speed of the drive shaft without or preferably with full opening of the suction throttle.

In one development, the method for controlling or regulating the output volume flow, power or torque of the inventive in-line piston pump uses a device by means of which the volume flow that the fluid to be pumped can be conducted to the suction side is adjusted, which itself can be adjusted by means of an actuator, which in turn receives control signals from a controller. In a preferred variant, the controller receives at least one second message or an input signal of a further unit, which inputs mechanical power to the inline piston pump according to the invention and/or receives hydraulic power of the inline piston pump. Alternatively or additionally to this variant, at least one operating parameter of the inline piston pump according to the invention is input into the controller.

The invention further relates to a method for controlling or regulating an inline piston pump (in particular for outputting volume flow, power and torque), wherein the inline piston pump has at least two high-pressure outlets which are separated from one another and thus through which at least two volume flows separated from one another can be conducted in each case into a separate high-pressure inlet of a switching valve. In this arrangement, the controllable switching valve provides for this purpose an output volume flow, with any of the possible sums of the inlet volume flows being variable in terms of parameters and variable in terms of degrees of freedom.

In one embodiment, the method for controlling or regulating the output volume flow, power or torque of the inline piston pump according to the invention uses a switching valve which can be adjusted via a telemetric data exchange, preferably via an actuator integrated in the switching valve, which in turn receives a control signal from a controller. In a preferred variant, the controller receives at least one second information item or an input signal for a further unit which supplies mechanical power to the inventive inline piston pump and/or receives hydraulic power from the inline piston pump. Alternatively or additionally to this variant, at least one operating parameter of the inline piston pump is input to the controller.

Drawings

Other features, characteristics and advantages are set forth in the description of the figures that follows. In which is shown:

FIG. 1 shows a schematic cross-sectional view of an inline piston pump of the present invention transverse to the axis of the drive shaft;

FIG. 2 shows a schematic cross-sectional view of the inline piston pump of the present invention along the axis of the drive shaft;

FIG. 3 shows a perspective view of an inline piston pump of the present invention;

FIG. 4 shows a schematic cross-sectional view of the inline piston pump of the present invention through the top cover housing part with the valve piston of the suction throttle valve located therein open;

FIG. 5 shows a perspective view of a centering element of an in-line piston pump;

FIG. 6 shows a schematic cross-sectional view of the inline piston pump of the present invention through the top cover housing component with the suction throttle valve located therein;

FIG. 7 shows an enlarged view of a first longitudinal section of the valve piston of FIG. 6 having an annular space;

FIG. 8 shows a schematic diagram of one embodiment for controlling or regulating an in-line piston pump by a motor;

FIG. 9 shows a schematic view of an embodiment of the components acting in the intake throttle valve;

FIG. 10 shows another schematic view of an element acting in the area of the control element; and

FIG. 11 shows a block diagram illustrating an example of an application for regulating an in-line piston pump;

FIG. 12 shows a schematic view of an inline piston pump of the present invention with two fluidly isolated outlet connections;

fig. 13 shows a schematic view of the device of the invention, in which a variable volume flow is generated by means of an on-off valve.

Detailed Description

Fig. 1 shows a cross-sectional view of an embodiment of an in-line piston pump 1 according to the invention.

A known plunger unit comprises a piston 3 which compresses a fluid to be pumped through a first check valve (shown as a suction valve 11) into an oil-tight space and sends the fluid out via a second check valve (shown as a high-pressure check valve 10). Here, a plurality of plunger units are arranged one after the other in the direction of the drive shaft axis 4. Each piston 3 interacts with the drive shaft 2 and is thus arranged such that its longitudinal axis is oriented as radially as possible with respect to the drive shaft axis 4. The inline piston pump 1 preferably comprises three

housing parts

6, 8, 13. The lower housing part 6, hereinafter referred to as the base housing part 6, houses the portion of the drive shaft 2 that is placed inside the pump, the piston 3 and the high pressure check valve 10 (outlet valve) on the high pressure side of the respective plunger unit. The oil-tight space comprises the entire volume of the plunger unit that is filled with the fluid to be delivered to the extent that the suction valve 11 and the high-pressure check valve 10 of the plunger unit are sealed.

The upper housing part 8 (also referred to as the top housing part 8) contains a suction valve 11 (inlet valve). The two

housing parts

6, 8 are delimited from each other via a planar and preferably planar contact area 9.

For example, the control element 12 can be configured for a specific transmission rotational speed of the volume flow of the fluid delivered by the inline piston pump 1 in such a way that an inflow to the suction side of the fluid of the inline piston pump 1 is defined. The inline piston pump 1 has a preferred design configuration and is structurally optimized.

As can be further seen from fig. 1, the piston 3 is accommodated in a reciprocating manner in a piston chamber 5 which is arranged in part in the top housing part 8 and the base housing part 6. In this exemplary embodiment, the piston 3 has a centrally arranged pin 31, which is inserted into the top housing part 8. The upward and downward movement of the piston 3 is achieved by the rotation of the drive shaft 2 provided with a cam and the spring 32 supported on the piston 3.

Furthermore, a mounting flange part 13 can be seen, by means of which the inline piston pump 1 can be fastened to a component, not shown.

The work flow of the inline piston pump 1 follows. First, the fluid to be pumped is made to flow into the oil-sealed space via the suction valve 11 because the piston 3 moves on a path from the top dead center to the bottom dead center. The spring 32 supported on the piston 3 serves to move the piston 3 to the lower dead point, so that a continuously acting connection between the piston 3 and the drive shaft 2 is ensured. Due to the increase in the oil-tight space and the resulting low pressure caused by the piston movement, the suction valve 11 is forced to its open position counter to the pre-pressure of the spring 16, which causes the fluid to be pumped to enter or be sucked into the oil-tight space. In this process, the high pressure check valve 10 is in its latched position.

In the movement of the piston 3 from the lower dead point to the upper dead point, the pressure in the oil-sealed space increases, the suction valve closes, and the fluid in the high-pressure environment flows to the high-pressure side of the inline piston pump 1 via the high-pressure check valve 10 which is opened at this time.

Fig. 2 shows a sectional view of the considered embodiment of the drive shaft 2 in the longitudinal direction, from which the arrangement of the plunger unit can be seen. Several pistons 3, each oriented with their longitudinal axis as radially as possible with respect to the drive shaft axis 4, are arranged one after the other in the longitudinal direction of the drive shaft 2 and interact with a specially shaped section of the drive shaft 2 in each case in order to achieve a continuous delivery of the fluid.

It will be appreciated that the three plunger units shown, which are arranged one after the other in the geometric configuration, are connected upstream to a common suction channel 40, from which the fluid to be delivered is delivered into the respective oil-tight space via the respective suction valve 11. In the movement of the piston 3 from the lower dead point to the upper dead point, no fluid passes from the relevant oil-tight space into the suction channel 40, since the suction valve-plunger 111 is forced into the closed position by the force generated by the spring 16.

The force-locking of the spring 16 to the intake valve plunger 111 and of the spring 32 to the piston 3 is achieved in that the two

springs

16, 32 are supported on a centering element 15, which is arranged rigidly in a recess forming the piston chamber 5. The support of the

springs

16, 32 on the centering element 15 therefore provides the precondition that the piston 3 is pressed via the spring 32 against the cam of the drive shaft 2 and, if there is a low pressure in the oil-tight space, the suction valve plunger 111 is pressed via the spring 16 against its contact surface in order to close the suction valve 11.

The centering element 15 can be completely inserted into the top housing part 8 and fixed therein by the base housing part 6.

As is further shown in fig. 2, a mounting flange part 13 is attached to the base housing part 6, which mounting flange part centers the drive shaft 2 and has an opening through which the end section of the drive shaft 2 located outside the base housing part 6 is guided directly outward. In the embodiment shown, the drive shaft 2 can be enlarged and mounted from the base housing part 6 when the flange part 13 is removed. The intervention to the drive shaft 2 is here only achieved via the mounting flange part 13.

The invention comprises a development, wherein the intervention (not shown in the figures) can also be effected by the cover side of the cylindrical housing section of the base housing part 6 facing away from the flange mounting part 13. This can be achieved by additional modifications of the base housing part 6 or by a corresponding structural design. A corresponding alternative can be realized in that the cover side of the base housing part 6 mentioned can be closed and opened via a cover embodied as a separate component. The drive shaft 2 can also be inserted into the base housing part 6 or expanded through the opening, provided that the diameter of the opening of the base housing part 6 closed by the cover is appropriately dimensioned. The mounting flange part 13 can then be connected in one piece with the base housing part 6 on the front side of the inline piston pump 1, on which front side a drive shaft engagement is present for driving the inline piston pump 1. In this embodiment (with the mentioned embodiment with the top cover closed), the base housing part 6 can thus be embodied in such a way that the second inline piston pump 1, which is arranged in the opposite direction, can be screwed back to back with the first inline piston pump, and that a rotationally fixed coupling of the two drive shafts 2 is achieved by means of a corresponding engagement, wherein the form of the base housing part 6 is also realized in such a way that the drive shaft engagement is covered by the two mutually fixed base housing parts 6. In such an extension, the two drive shaft chambers of the two inline piston pumps, which are formed on one another, form a common volume. The contact areas of the two base housing parts 6 are closed by a sealing system.

Fig. 3 shows a perspective view of the inline piston pump 1, from which the three-part housing construction can be seen. The top cover housing part 8 rests on the base housing part 6, which in turn is connected to a mounting flange part 13.

The high-pressure connection 20 of the inline piston pump 1 may here be arranged on the side of the base housing part 6 opposite the mounting flange part 13.

According to an alternative configuration, however, the mounting flange part 13 can also be arranged on the same side as the high-pressure connection 20 in relation to the embodiment of fig. 2, wherein, in turn, the drive shaft section on the drive side is preferably guided outward via an opening region and a centering region which are integrally formed with the base housing part 6, the mounting flange part 13 covering the driven-side part of the drive shaft 2 in the mounted state to the base housing part 6 and leaving the end section of the drive shaft 2 exposed in the dismounted state, as a result of which a connection to the drive shaft of a further component to be mounted is made possible. The member to be mounted as described herein may be an in-line piston pump of the same configuration, or other type of hydraulic pump, or an electromechanical machine, or the like.

Fig. 4 shows a top view of the section 91 provided in the head housing part 8, which shows the piston bore of the suction throttle valve and the valve piston 124. Along the exposed flow path of the suction connection 18, an annular space can be seen through which the fluid passes to the suction channel 40. Three inlet openings are also visible, through which fluid can pass from the suction channel 40 into the piston chamber 5 at the open suction valve 11. There is a fluid connection between the introduction hole and the suction channel 40, which continues to the suction connection 18 when the suction throttle valve is opened. The suction throttle can influence the inflow of the fluid to be delivered into the suction line depending on its position.

The suction connection 18 need not necessarily be arranged on the side wall of the top housing part 8, as shown, but can also be located on the other side, or on the top side thereof. It is also possible to have a plurality of openings, one of which can be used as the suction connection 18 and the other of which can be closed. Preferably, the opening or openings are located on the side wall and/or on the upper side of the housing part 8.

Fig. 5 is a perspective view of the centering element 15, which comprises an inner annular element 153 and an opposite outer annular element 152, wherein the inner annular element 153 and the outer annular element 152 are arranged coaxially with respect to one another. The two

ring elements

152, 153 are connected to a web 158, the inner ring element 153 having an inwardly directed flange region 154 on the inside, on which the spring 16 for the valve plunger is supported. The central recess 155 can be penetrated by the pin 31 of the piston 3 in the corresponding stroke condition.

It is also possible to ascertain that the drive shaft 2 may alternatively be designed as a crankshaft or an eccentric shaft, with the piston 3 being indirectly operatively connected thereto. If the drive shaft 2 is embodied as a camshaft, a direct functional connection is preferred for economic reasons. By direct connection is meant that the end face of the piston 3 is in direct contact with its opposing cam. A guide wheel, preferably at least a ball bearing, if appropriate a sliding element, via which rolling or sliding on the rotating cam is effected, can be fastened to the piston 3. An indirect functional connection is then formed between the piston 3 and the drive shaft 2.

The fluid may in particular be oil or hydraulic oil. For the sake of readability, in the following description, the designations relating to fluids are used, with the term: oil pressure, oil flow, oil mass, oil temperature, oil mass, oil tank, oil-dead-center volume, oil seals, and the like. This is not meant to be limited to oil as the fluid.

Either plunger unit comprises an inlet valve, preferably implemented as a check valve, on the inlet side (shown as a suction valve 11), a piston 3 and a check valve, shown as a high pressure check valve, on the high pressure side as an outlet valve. The in-line piston pump 1 shown in the figure has three plunger units and is equipped with a camshaft 2 having a double cam (see fig. 1). The three plunger units deliver fluid (which may be referred to herein as oil) to a common high-pressure connection 17 of the in-line piston pump 1.

The support of the piston 3 on the cam opposite it is achieved by the spring 32 even during the intake operation. Since a double cam is used in this embodiment, two lifting processes of the piston 3 are realized during one full revolution of the drive shaft 2. If the piston 3 is observed to move from OT (top dead center) to UT (bottom dead center) during rotation of the camshaft, a low pressure is provided by the observed increase in volume of the oil-tight space of the plunger unit. Due to the higher oil pressure on the suction side, the suction valve 11 opens, as a result of which the oil circulates out of the oil tank and is introduced smoothly in the direction of the oil-tight space of the plunger unit as viewed. After exceeding UT (bottom dead center), the volume of the oil-tight space decreases as a result of the constant immersion of the piston 3 in its receiving recess 7. The resulting pressure increase in the oil volume contained in the oil-tight space in the plunger unit thus observed causes the suction valve 11 to close. After a further pressure rise, the high-pressure check valve 10 of the plunger unit is observed to open. The two check valves of each plunger unit further function so that different plunger units do not interfere with each other; to avoid that oil brought to a high pressure level by one plunger unit passes the adjacent plunger unit to the suction side.

A similar functional relationship between the piston movement and the switching state of the two non-return valves of one plunger unit can also be achieved by using an eccentric shaft or a crankshaft.

The components mounted in the housing for the intake valve 11 and the piston 3 of a plunger unit preferably have an imaginary common longitudinal axis 71 which is oriented radially toward the drive shaft axis 4 (see fig. 2).

The following components are involved: piston 3, spring 32, suction valve-plunger 111, spring 16 and centering element 15. The longitudinal axis 71 is likewise the longitudinal axis of the recess forming the piston chamber 5 and of the receiving recess 7 of the piston connected thereto. Said recess extends through the

housing parts

6, 8 and is accommodated therein as described above.

The suction valve-plunger 111 may be in the shape of a thimble. The piston 3 can be guided along its side in the receiving recess 7 and is preferably embodied as a hollow piston. In a particularly preferred embodiment, the piston has a central pin 31 on the side opposite the drive shaft 2, the longitudinal length of which exceeds the longitudinal length of the piston wall. Whereby a part of the spring 32 is present inside the piston 3. The lower end of the annular space terminates on the inner bottom of the piston 3, on which the end of the spring 32 bears. The region of the spring 32 opposite thereto projects beyond the open upper side of the annular space. The spring 32 is supported at its ends on the centering element 15. A detailed embodiment of such a centering element 15 can be seen in fig. 5 and is explained below. The spring 32 can be made to lie almost completely in the annular space of the piston 3 when it is compressed with its minimum length, which can occur in its mounted state. The cross section of the annular space must be dimensioned correspondingly wide so as not to impede the movement of the spring 32, but should nevertheless be as small as possible in order to limit the oil-dead volume as strictly as possible.

The rod-shaped section of the suction valve plunger 111 has an inner diameter which is adapted to the outer diameter of the inner wall 153 of the centering element 15, whereby the guidance of the suction valve plunger 111 is achieved. On the inside of the inner wall 153 of the centering element 15, there is a projection or a support surface 158 on which the spring 16 can be supported. The opposite end side of the spring 16 is supported at the bottom of the blind hole of the suction valve plunger 111. The spring constant of spring 16 is substantially less than the spring constant of spring 32. The spring 16 must be compressed to the maximum extent already at only a small depression (referred to as pressure level in the tank when the volume of the plunger space increases) in order to release the flow cross section at the suction valve 11. As already mentioned, the spring 32 must ensure that the punch surface of the piston 3 is pressed against the cam contour even in the UT position by a correspondingly high restoring force.

During operation of the inline piston pump 1, the movement of the piston 3 and the intake valve plunger 111 takes place in the direction of the imaginary longitudinal axis 71.

In a preferred embodiment, the pin 31 of the piston 3 is designed such that it fills the greatest possible proportion of the volume of the free blind hole of the intake valve plunger 111 in the OT position (see fig. 1). The partial volume of the blind bore of the suction valve plunger 111 which is alternately filled and unfilled by the pin 31 is thereby used to achieve an oil seal. Furthermore, the pin end near the bottom of the blind hole of the suction valve plunger 111 facilitates a rapid closing of the suction valve 11 when the piston 3 moves from UT towards OT.

Three forces act on the plunger of the high pressure check valve 10 (see fig. 1). The plunger provides a bearing surface for the fluid in the high pressure channel 17 of the in-line piston pump 1. In the same direction, that is, the latching direction of the high pressure check valve 10, the restoring force of its spring acts. As long as the oil pressure in the observed oil-tight space is sufficiently large, the force acting in the flow direction of the high-pressure check valve 10 is sufficiently large to open the high-pressure check valve. Once the high pressure check valve 10 opens, the plunger unit provides hydraulic power that is released through the high pressure passage 17 and the high pressure connection 20 of the in-line piston pump 1.

The plunger guidance at the high-pressure check valve 10 is effected analogously to at the suction valve 11. In contrast to the intake valve 11 installed in the housing 8, for the exemplary embodiment of the high-pressure check valve 10, additional components as shown in fig. 1 are respectively installed in the housing 6, whereby the high-pressure check valve 10 is pressure-sealed in the closing direction.

For each plunger unit there is a cross section through which the longitudinal section through the piston 3, the central longitudinal section through the suction valve 11 as well as the central longitudinal section through the high-pressure non-return valve 10 are exposed. The cross-section and the axis of the drive shaft 2 are preferably perpendicular to each other.

In either plunger unit, the central axis of the accommodation recess 7 for the piston 3 and the central axis of the bore for the high-pressure check valve 10 are arranged in an angular range of between 15 ° and 60 °, preferably between 25 ° and 45 °.

The acute angle enables a smaller width dimension of the inline piston pump 1 and, up to a known range, an increase in the power density of the inline piston pump 1; and (it may be decisive for the installation performance of the inline piston pump 1 on a specific drive assembly, for example on a power take-off of an internal combustion engine or on a multi-circuit unit) also requires a strong return of the oil circuit of the fluid brought to a high pressure level. An acute angle is therefore particularly disadvantageous, since a strong return leads to a higher pressure loss. In particular, acute angles are also disadvantageous because of the increased overall height of the inline piston pump 1.

The centering elements in the

valves

10, 11 provide a significant contribution, namely enabling the configuration of the inline piston pump 1 shown as an example to be easily maintained.

Moreover, the embodiment of the centering element 15 shown in perspective in fig. 5 has a relatively simple construction. The bottom of which has the form of a disc with two kidney-shaped openings and a centrally located circular opening 155. Furthermore, the centering element 15 has two

wall regions

153, 152 in the form of concentric circles. As can be appreciated, such centering elements 15 are made of circular material mostly as a rotating piece by a unique tightening process. Only the machining of the kidney-shaped opening has to be carried out additionally, for example by milling.

In this embodiment, each plunger unit is fitted with two centering elements 15 (each valve 10, 11). In this configuration, the centering element 15 used in the region of the intake valve 11 can be embodied as the centering element 15 used in the high-pressure check valve 10. Of course, due to the limited installation space required, a smaller size of the centering element 15 is preferred in the region of the high-pressure check valve 10 than in the region of the intake valve 11, since a smaller flow cross section is provided in the intake region, i.e. a disadvantage can be clearly perceived in the low-pressure region than in the high-pressure region.

In the perspective view of the centering element 15 shown in fig. 5, the two kidney-shaped regions are each a component of the flow cross section and have a local constriction along the flow path. As can be readily appreciated, the reduction of the outer diameter of the centering element 15 (while maintaining other dimensions not related to this dimension) leads to a reduction of the two kidney-shaped flow cross sections.

Preferably, the housing of the in-line piston pump 1 according to the invention is composed of a base housing part 6 and a top cover housing part 8 and a third mounting flange part 13 (see fig. 2).

The base housing part 6 may have approximately the form of two geometrical basic bodies assembled together and one of which is cylindrical and one cubic. In this embodiment, the drive shaft 2 and its bearing (exactly one bearing in this embodiment) are located inside a cylindrical partial region, whereas the interior volume of a cubic partial region accommodates the piston 3 and the high-pressure check valve 10 of the in-line piston pump 1 and the high-pressure connection 20.

The top cover housing part 8 may approximately have the form of a cube. The top housing part has a suction connection 18, while the interior volume of the top housing part 8 has a suction valve 11. Furthermore, the parts of the device 12 for adjusting or controlling the in-line piston pump 1 can be arranged in the top housing part 8. Preferably such means 12 is an intake throttle valve. In the exemplary embodiment shown in fig. 4, only one preferred embodiment of a valve piston 124 for the intake throttle valve is shown, which is mounted in its bore. The intake throttle valve is generally known to the skilled person.

The

housing parts

6 and 8 are in direct contact with one another by surface contact of the contact region 9 or indirectly via the sealing element 19. It is particularly preferably provided that the planar design is located on a level E1 which extends parallel to the drive shaft 2. Particularly preferably, in the mathematical sense, the vector along the longitudinal axis 71 for the or each receiving recess 7 of the piston 3 is a normal vector relative to the level E1.

In a first variant of the pump housing, the cylindrical partial cross section of the base housing part 6 on the side where the drive shaft 2 is directed outwards is not covered.

The closure of the pump housing here takes over the components shown as mounting flange parts 13, which (as the name suggests) are embodied in the form of flanges and are mounted on the base housing part 6, in this case preferably in a planar manner on the end side of the cylindrical wall of the base housing part 6.

From the base housing part 6, on its outlet side, the drive shaft 2 is centered by the mounting flange part 13 and is guided outwards via a longitudinal opening therein and is supported in its longitudinal region by a front drive shaft bearing 48 mounted in the mounting flange part 13.

At the base housing part 6, the closed top side of the cylindrical partial region is shaped in such a way that the installed drive shaft 2 is preferably received by a rear drive shaft bearing 49 fastened directly thereto. At least at the inline piston pump 1 with a relatively small number of pistons, there are no further drive shaft bearings. Rolling or sliding bearings can be used as the drive shaft bearing. Such a plain bearing is preferred, so that it can absorb radial and axial forces, and is shown as a thrust plain bearing.

By tapering the diameter at the longitudinal end of the drive shaft 2, the support thereof can be achieved in a simple manner by means of a drive shaft bearing 48 at the front end (preferably fixed to the mounting flange part 13) and by means of a drive shaft bearing 49 at the rear end (preferably fixed to the base housing part 6).

The sealing between the mounting flange member 13 and the base housing member 6 is achieved by means of a seal B, such as an O-ring. The sealing between the mounting flange part 13 and the drive shaft 2 is achieved by means of a seal a, for example by means of a sealing ring with a sealing lip (see fig. 2).

The base housing part 6 has, at the open end side of the cylindrical subregion, a plurality of vertically perforated clamping webs which are flush with the cylindrical wall at the level which is provided as an abutment face for the mounting flange part 13.

The cuboid region of the base housing part 6 is preferably designed such that it encloses as little circumference of the cylindrical region as possible. The hole pattern of the clamping plate can be machined from an existing hole, from the inside during the manufacturing of the mounting flange part 13, in particular when the mounting flange part 13 is manufactured as a casting.

In a preferred embodiment, the hole pattern is brought over and over again around the mounting flange member 13. In this way, an in-line piston pump 1 is provided which can be assembled without excessive additional expenditure even in other installation positions as an original/primary design. The in-line piston pump 1 is usable in a condition matched to a single component (i.e. in the case of retrofitting the mounting flange part 13 or in the case of selecting other flange types for different assembly adjustments), for which all other components of the in-line piston pump 1 can be permanently retained. (for example, an SAE-B type flange may be used instead of the embodiment shown in the drawings in which an SAE-A type flange is present.)

It can be advantageous for the base housing part 6 to have a cylindrical housing region with a further enlarged geometry in the end region of its closed longitudinal end, which is realized as a support structure for the drive shaft 2. If such a construction space is provided, the corresponding cover face on the longitudinal end of the base housing part 6 can be removed and a further inline piston pump can be installed, that is to say a serial arrangement of two inline piston pumps is achieved. The retrofitting of the base housing part 6 involves the installation of a further in-line piston pump 1. The coupling of the drive mechanisms of the two hydraulic pumps can be realized, for example, by a drive shaft engagement mechanism. Instead of an inline piston pump 1 of the same construction, it is of course also possible to provide a rotary drive of a hydraulic pump, of an air compressor or of an electric motor of completely other construction, etc.

As long as the pump housing is constructed as described above, aluminum or an alloy containing aluminum may be preferably used for the mounting flange part 13.

In a further variant, which is not shown in the figures, the entire flange region of the inline piston pump 1 is located directly on the base housing part 6, so that despite the strict limitation of "flexibility in being able to adapt to different constructional spatial relationships", a simple construction of the series arrangement of two inline piston pumps 1 is possible without having to increase the manufacturing expenditure of the base housing part 6, without having to remove the mounting flange part 13 as an additional separate component. In this embodiment, a mounting flange is integrally connected to the base housing part, which mounting flange is located on the side of the in-line piston pump 1 directed outwards by the drive shaft 2. The centering of the drive shaft 2, the accommodation of the front drive shaft bearing 48 and the seal B is thus in the base housing part 6. The seal B may be removed. The mounting and enlargement of the drive shaft 2 is directed outwards via an opening of the drive shaft chamber, which opening is located on the side opposite the base housing part 6. This opening is closed by a mounting part in the form of a top cover when the drive shaft 2 is mounted. Preferably, the base housing part 6 is designed in such a way that a further base housing part 6, which is arranged in the opposite direction, can be screwed back to back with it. If a series arrangement of two in-line piston pumps 1 is modified in this way, the two drive shaft chambers form a common volume which preferably also covers the drive shaft engagement mechanism. The contact areas of the two base housing parts 6 are closed by a sealing system.

It is of course conceivable that, in a third variant, which is likewise not shown in the figures, the inline piston pump 1 according to the invention has a housing which is not complete, but a part of the housing of the inline piston pump is already a component of the other housing, i.e. the inline piston pump 1 according to the invention is used as a mounting pump. In addition to the variations directly obtained therefrom, other features already mentioned are advantageous here; especially the retention properties described in the subsequent paragraphs.

The separation point between the base housing part 6 and the top housing part 8 is preferably determined such that the suction valve 11 is located as completely as possible in the top housing part 8, for which purpose the receiving recess 7 of the piston 3 is located in the base housing part 6 and the high-pressure check valve 10 is located as completely as possible in the base housing part 6 or as completely as possible in the top housing part 8 (not shown in the figures). For the reasons mentioned above, the pin 31 located on the piston 3 projects into the top cover housing part 8. This arrangement offers the advantage that the components or assemblies described are accessible for assembly/disassembly and good accessibility of the respective mounting end positions in the

housing parts

6 and 8 is possible.

In particular, the separation point between the base housing part 6 and the top housing part 8 is preferably determined in such a way that the intake valve 11 is located completely in the top housing part 8, for which purpose the receiving recess 7 of the piston 3 is located completely in the base housing part 6 and the high-pressure check valve 10 is located either completely in the base housing part 6 or completely in the top housing part 8 (not shown in the figures). As long as the bore wall of the receiving recess 7 (i.e. the contact surface of the piston wall) is located only in the base housing part 6, the finishing of the contact surface on the housing part can be defined in a clear manner. The distribution of the

housing parts

6 and 8 described above thus offers the advantage that the contact surface for the upper side of the suction valve plunger 111 can be machined directly into the cover housing part 8, although the dimensional accuracy and surface quality of the contact surface described here are very demanding in order to enable a high-pressure-tight closure of the suction valve 11 in the closing direction. With the use of a corresponding special drill, the contact surfaces can be machined in one step together with the groove finishing, in which the centering element 15 is mounted.

During assembly or during disassembly of the inline piston pump 1 according to the invention, the two

housing parts

6 and 8 are positioned such that their respective faces (referred to as contact regions 9, which are preferably embodied as side faces E1 with respect to the assembled inline piston pump 1) are freely arranged and from which the installation or disassembly of the intake valve 11, the piston 3 and the high-pressure check valve 10 can be carried out. Due to such a housing division, good accessibility to the assembly is achieved with corresponding subsequent advantages.

Instead of the sealing measure of the entire separation between the

housing parts

6 and 8, a sealing system with individual seals or at least one individual seal and at least one further structural element with additional functions relating to the sealing is preferably applied in the planar contact region 9 between the

housing parts

6 and 8. The structural elements refer to the sealing aid element and the control element for visual and/or tactile control of the installation position and/or installation orientation. Preferably, the individual seals and structural elements are applied to the seal carrier which is then mounted as a whole during the assembly of the in-line piston pump 1. The sealing system may be comprised by a positioning element which does not require flange mounting or at least allows identification from the outside.

The inline piston pump 1 can have at least one bore as a suction connection 18, which is preferably located on the top housing part 8. The suction connection 18 can be arranged, as shown in fig. 4, by means of a bore hole made from a longitudinal side wall or from a wall arranged radially with respect to the base housing part 6, so that an oil connection is produced which is preferably perpendicular to the suction channel 40. If a device 12, which is preferably embodied as a suction throttle, is provided in the top housing part 8, the suction channel 40 and the opening for the placement of the suction connection 18 are preferably arranged opposite one another in such a relative position for the placement of the device 12 that the bore of the suction connection 18 formed in the suction channel 40 is as perpendicular as possible to the bore for the placement of the device 12 (see fig. 4). In order to achieve a high flexibility in the assembly or installation of the inline piston pump 1, additional openings can be provided which serve as suction connections 18, thereby achieving a certain degree of flexibility for the openings which actually serve as suction connections 18. Such a possibility is, for example, the arrangement of a further opening, the axis of which is designed parallel to the respective direction of movement of the pistons of the inline piston pump 1.

One of the openings then functions in a well-defined manner as a suction connection 18, while the other openings must be sealed.

The inline piston pump 1 has at least one bore which serves as a high-pressure connection 20, wherein the high-pressure connection is preferably located on the

respective housing part

6 or 8 which contains the high-pressure check valve. As shown in fig. 3, the modified positioning of the high-pressure connection 20 with low expenditure is a continuation of the outward development of the high-pressure channel 17 shown in fig. 1. An alternative or suitable additional positioning opening is a bore hole which emerges from the longitudinal side wall of the housing part 6 and which meets the high-pressure channel 17 and is preferably as perpendicular as possible to the high-pressure channel 17.

The unnecessary openings for the other suction connections 18 and high-pressure connections 20 may or must be pressure-tightly closed. Alternatively, one of the different openings can be selected as the intake connection 18, so that the inline piston pump 1 can be easily adapted to different accessibility and constructional space relationships. Likewise, one of the different openings can be used as an option for the high-pressure connection 20, making the inline piston pump 1 easily adaptable to different accessibility and constructional space relationships.

In order to conduct oil leakage away from the drive shaft chamber (i.e. the cylindrical region of the base housing part 6 in which the drive shaft 2 is located), an oil connection can extend from this drive shaft chamber as far as the suction side (i.e. in the interior volume of the housing top cover 8), wherein this oil connection preferably extends inside the housing wall. This has the advantage that the leakage must not only be returned to the tank, but also to the intake side of the inline piston pump 1. With regard to the flow direction of the fluid to be pumped, the mentioned oil leakage to be conducted out preferably ends up in the device 12 upstream of the flow. In order to avoid a dry suction of the drive shaft chamber with corresponding indirect losses, the oil connection used as a leakage line can be replaced by a high-pressure valve.

In order to conduct the leakage away from the housing part 13, a plurality of oil connections are preferably provided, which are provided such that the leakage conduction can be ensured independently of the installation angle of the inline piston pump. For purposes of explanation: the preferred mounting angle is to position the base housing component 6 below the top cover 8. However, due to the spatial design, the cover 8 can also be arranged below the base housing part.

Fig. 6 shows a schematic sectional view of an inline piston pump 1 according to the invention through a housing part of a top cover, wherein the device 12 embodied as a suction throttle valve arranged inside is opened for adjusting the volume flow of the fluid to be delivered and is positioned by a closing element (21) and a spring (22).

It will be appreciated that in this embodiment the valve piston 124 is embodied as a differential piston having a first longitudinal section 121 of relatively large diameter and a second longitudinal section 122 of relatively small diameter. Here, a second longitudinal section 122, the distal end of which is located in the control chamber, leads in a suitably dimensioned bore to the control chamber via the control pressure bore 23. The control pressure bore 23 can have an oil connection to the high-pressure side of the inline piston pump 1, either directly or via a pressure reducer 81, or an oil connection to a pressure source which is sealed off from the high-pressure side of the inline piston pump 1, that is to say an oil connection to a pressure source which is hydraulically separated from the high-pressure side of the inline piston pump 1. As soon as the pressure level caused via the control pressure bore 23 of the valve piston 124 on the end side as the control surface exceeds a predetermined threshold value, a further increase in this pressure level causes an increasing displacement of the valve piston 124 counter to the action of the spring 22 in the direction of the narrowing of the opening cross section formed by the suction throttle. The volume flow occupied via the suction connection 18 to the suction channel 40 can be adjusted by adjusting the valve piston 124 and thus at the level of the control pressure caused via the control pressure bore 23.

The valve piston 124 is preferably embodied as a differential piston, particularly preferably in two parts. The (thinner) second longitudinal section 122 of the valve piston 124 is preferably configured or adapted as a needle roll. The (thicker) first longitudinal section 121 of the valve piston 124 has a narrowing 125 in a predetermined length region. In this way, there is an annular space in the pump head at the piston bore, whereby the size of the opening cross section from the suction port 18 to the suction channel 40 depends on the axial position of the valve piston 124. Preferably, the valve piston 124 has at least three contact surfaces, and particularly preferably exactly three contact surfaces. With regard to the valve piston 124, the first contact surface is formed by the outer circumferential surface of the (thinner) second longitudinal section 122 of the valve piston 124. The second and third contact surfaces are formed by the outer circumferential surfaces of two regions which are located in the first longitudinal section 121 of the valve piston 124 and are separated from one another by a narrowing 125.

Fig. 6 shows the valve piston 124 in the left-hand end-contact position, or in the end-contact position when the control pressure is too low, as a result of which the pretension generated by the spring 22 is overcome. This end abutment position of the valve piston 124 is achieved in that its shoulder region abuts against the bottom of the blind hole of the piston bore. Even if this is not shown precisely in fig. 6, in the end-abutting position of the valve piston 124, there is a maximum opening cross section at the intake throttle, wherein the valve piston 124 is moved to the right, which is caused by a correspondingly higher control pressure, and this movement leads to an increasing narrowing of the opening cross section. In this end-abutting position, the annular space on the valve piston 124 interacts with the connecting channel, in particular is aligned, in such a way that the throttle effect of the suction throttle valve is practically minimized, wherein the fluid is guided via the connecting channel to the suction channel 40 after the annular space has circulated.

On the right, the valve piston 124 is prestressed by the spring 22, so that the valve piston 124 bears against its left stop. The region of the valve piston 124 with the substantially smaller diameter is preferably made of a needle coil 122 which is mounted on a further component which forms the first longitudinal section 121 of the valve piston 124 with the larger diameter. The open punched surface of the second longitudinal section 122 can be used as a control surface for the valve piston 124, whereby the oil connection is realized by means of an existing bore. The oil pressure here generates a force that overcomes the restoring force of the spring 23 to move the valve piston 124. In order to avoid a complete retraction of the intake port 12, which serves to maintain the self-lubricating properties of the inline piston pump 1, the particularly easily illustrated closing element 21, which is preferably embodied as a locking bolt, has a pin for the right-hand end abutment of the valve piston 124.

On the one hand, it must be avoided: a relatively large amount of oil is displaced from the control chamber or the control pressure bore 23 in response to leakage and flows out along the gap between the second longitudinal section 122 of the valve piston 124 and the piston bore and reaches the bottom of the blind bore and accumulates there, as a result of which the advanced end of the valve piston 124 comes into contact, with the result that the suction throttle valve can no longer reach its maximum opening position. To avoid this, a leakage lead-out portion may be provided (see fig. 7). On the other hand, lubrication of the guide surface of the piston 121 requires a certain introduction of oil.

Fig. 7 shows a close-up view of the first longitudinal section 121 of the valve piston 124 from the installation shown in fig. 6 described previously.

Here, a valve piston 124 is shown according to a particularly preferred embodiment of the invention. A longitudinal bore 123 is seen, arranged parallel to the longitudinal axis of the valve piston, running through the annular space formed by the narrowing 125. The leakage oil which is pressed out by the control chamber can thus reach this longitudinal bore 123, with a recess 127 on the end side of the (thicker) first longitudinal section 121 of the valve piston 124, so that an oil connection from the control chamber 23 to the suction side of the inline piston pump 1 is provided, including the volume provided by the chamfer 126 of the piston bore. By specifically balancing the flow resistance provided in the longitudinal direction of the valve piston 124 via the described bore hole (for example by means of a corresponding bore hole diameter or by means of a correspondingly dimensioned plunger), it is achieved that no leakage oil accumulates at the end face of the (thicker) first longitudinal section 121 of the valve piston 124 and that lubrication between the first longitudinal section 121 of the valve piston 124 and the corresponding contact surface of the piston bore hole is also achieved.

Fig. 8 shows an embodiment of the device according to the invention in a first variant and of an in-line piston pump 1 driven by means of an electric drive. In this exemplary embodiment, an electric motor 50 is provided which is driven by a three-phase current and which can be embodied, for example, as an asynchronous machine. The power supply can be effected via a frequency converter 70, which additionally acts as an actuator for the control device or regulating device. By adjusting the three output voltages and the supply frequency accordingly, the matching of the electrical input power of the asynchronous machine 50 to its rotational speed is achieved. In order to achieve a rotational speed/torque adaptation of the asynchronous motor 50 to the inline piston pump 1, a gear mechanism, which is not shown in the drawing, can be provided. In a corresponding arrangement, the operating range for the traction rotational speed and the torque supplied to the inline piston pump 1 are covered. The in-line piston pump 1 can thus provide a controllable volume flow at its working connection or its high-pressure connection 20, or a corresponding hydraulic power, which can be supplied by at least one hydraulic consumer and/or accumulator.

Preferably, one electric drive unit is provided for each in-line piston pump 1. Of course, it is possible for a plurality of inline piston pumps 1 to be used in part or for the entire electric drive unit to be used together, in particular in the case of a series arrangement of pumps.

In this exemplary embodiment, the rotational speed of the asynchronous machine is fed back via a rotational speed sensor 51 belonging to the control/regulating unit of the frequency converter 70. There is at least no direct feedback to the in-line piston pump 1 as to the actual value of the oil pressure at its operational output. Alternatively, the actual value of the oil pressure can be detected by an additional sensor, and likewise this sensor is provided by a control unit/regulating unit subordinate to the frequency converter 70.

In addition to the information flow shown in fig. 8, it can optionally be further derived that: in particular a pressure signal which, in a fixed relationship to the high pressure level of the in-line piston pump 1, represents in particular the pressure level at the high pressure channel (20) or at the high pressure outlet (17), which pressure signal is obtained, for example, by measurement by a pressure sensor in the high pressure channel 17 or at the high pressure connection 20; and/or a pressure signal which, in a fixed relationship to the pressure level in the suction region, represents in particular the pressure level at the suction connection 18 or in the suction channel 40. This achieves a regulating and/or controlling action of the inline piston pump 1. Feedback is provided by the adjustment mechanism.

Fig. 9 shows another embodiment of the present invention. In the illustrated embodiment of the inline piston pump 1, which is driven by the main drive 50 and is driven via the device 12 embodied as an intake throttle, the spring 32 is necessary, whereas two

further springs

222, 223 are optionally provided in order to be able to realize different characteristic curves.

In fig. 9, the valve piston is in the open position and can be brought into a blocking position by a leftward movement, in which only a volume flow is free which enables the in-line piston pump 1 to self-lubricate.

As shown in the figures, the spring 22 is embodied as a compression spring. Alternatively, a return spring embodied as the spring 22, for example a tension spring, can be additionally embodied, which is fastened to the valve piston 124 in such a way that the return force generated by it acts on the valve piston 124 independently of the position of the valve piston 124, wherein a force is generated in the opposite direction, which acts on a control surface of the valve piston 124 passing through the control pressure bore 23. In this embodiment, the control surface receives the high pressure pHD of the inline piston pump 1. In a constructive solution, an internal supply of high pressure is preferred. For example, the high-pressure drilling can be implemented as an oil connection between the high-pressure channel 17 and the control chamber.

Without the spring 223 shown in fig. 9, the schematic acts as follows: below a first defined pressure threshold value, the force generated by the high pressure pHD on the control surface is too low, as a result of which the valve piston is moved away from the rightward end abutment (not shown). At this end abutment of the valve piston 124, there is the largest possible opening cross section through the suction throttle from the suction port 18 to the suction channel 40 of the inline piston pump 1. From the exceeding of this first pressure threshold, the position of the valve piston 124 is balanced by the force between the restoring force of the spring 22 and the force due to the pressure level pHD against the control surface. As the pressure level pHD increases, the opening cross section in the intake throttle valve decreases until a second pressure threshold is reached. The spring 222 reaches its abutment surface so that the restoring forces of the two springs are opposed by the pressure level pHD of the spring on the control surface. In such a case, the pressure level pHD may have a corresponding height value, providing a third pressure threshold. Here, the valve piston 124 reaches its left-hand end abutment (not shown). Preferably, the intake throttle has an opening cross section at this point of the valve piston 124 which is sufficiently large for the self-supply of the inline piston pump 1, i.e. to avoid dry running.

The presence of the second spring 222 in the form shown makes it possible for the suction opening/constriction characteristic to be divided in two different regions. The presence of such a second spring 222 is optional, as is known. In a clear manner, the third characteristic curve region of the intake opening constriction can be realized in that instead of a single spring 222, two springs 222' and 222 ″ are used. In this embodiment, there is a collision of the spring 222' when the second pressure threshold is reached, and a collision of the spring 222 ″ when the third pressure threshold is reached. The left-hand end abutment of the valve piston is only achieved when a fourth pressure threshold is generated.

Alternatively or additionally, a further characteristic curve region of the intake opening constriction is achieved by the presence of the spring 223. After the second pressure threshold is exceeded, the force lock between the valve piston and the spring 223 is no longer established. Instead of a single spring 223, two springs 223' and 223 "may be used.

The presence of the spring 223 results in a greater pressure contraction at a lower operating pressure pHD, while the presence of the spring 222 results in a reduced contraction of the suction opening.

Fig. 9 also shows a simple embodiment of the suction inlet constriction, by means of which the oil pressure pHD in the operating region of the inline piston pump is maintained substantially constant at the high-pressure connection 29, i.e. at the operating output, as long as the spring has a constant spring rate in its operating region.

With regard to the orientation of the diagram, a force directed to the right on the valve piston 124 of the suction throttle is generated by the restoring force of the already pretensioned spring 222. The control surfaces on the valve piston 124 are oriented in such a way that the pressure impulses here generate a force directed to the left on the valve piston 124. By implementing an embodiment in which the spring pretension is adjusted manually, the pressure level of the cut-off pressure of the inline piston pump 1 can be changed manually. Preferably, the spring preload can be set so as not to lie in a region which permits a lower opening cross section than that of the intake throttle valve which prevents a low threshold value for the inflow of oil (which is just sufficient for the self-supply of the inline piston pump 1), so that dry running is avoided. This can be realized structurally in that the closing element of the valve bore is provided with a corresponding longitudinal pin which serves as an end abutment for the valve piston 124.

Fig. 10 shows a block diagram for switching the pump 1 and discloses another possibility for utilizing the device of the invention. Instead of a direct feedback of the high pressure pHD to the valve piston 124, the control surface can be impinged upon by a so-called reduced pressure pred, which is derived from the high pressure pHD and is obtained via the pressure reducer 81. As long as this reduction is variably adjustable, for example by using an electrically controlled pressure relief unit, a change in the cut-off pressure can be achieved even during operation of the device according to the invention. Alternatively, the position of the valve piston 124 and thus the throttling of the oil inflow on the suction side can be adjusted by means of an externally generated pressure, which can be generated, for example, by means of an auxiliary pump, whereby, as described above, the fluid volume flow of the in-line piston pump 1 can be adjusted.

Alternatively (not shown), the control surface can have an oil connection to the outlet of an additionally provided reversing valve which is connected via a first inlet (i) to the high pressure pHD of the inline piston pump 1 or to a pressure derived therefrom and (ii) to a second inlet via an externally generated pressure.

In a further alternative embodiment, the valve piston 124 can have a second control surface which is likewise designed such that the pressure level acting thereon likewise generates a force directed to the left on the valve piston 124. In this embodiment, the first control surface is impinged upon by the high pressure pHD of the inline piston pump 1 or by the pressure derived therefrom, and the second control surface is impinged upon by an externally generated pressure.

In a further alternative embodiment, the valve piston 124 may have a second control surface which is designed such that the pressure level acting on it generates a force directed to the right on the valve piston 124. In this embodiment, the first control surface is impinged upon by the high pressure pHD of the inline piston pump 1 or by the pressure derived therefrom, and the second control surface is impinged upon by an externally generated pressure. The spring 22 may also be eliminated in this embodiment.

The described embodiments enable different changes of the suction inlet contraction and thus of the different characteristic curves, which can be influenced even during operation. This makes it possible, for example, to use the device according to the invention as a power-adjustable in-line piston pump with a constant pHD Q, where Q is the oil volume flow at the working output of the in-line piston pump and pHD is the oil pressure there, when the respective assembly dimensions are used.

The externally generated control pressure can be, for example, the output pressure of an auxiliary pump or a control/regulating valve or valve arrangement, which is preferably arranged hydraulically upstream of the device 12 embodied as an intake throttle valve.

In the relevant figures (fig. 1), pressure connections are provided for guiding an externally generated control force to the valve piston 124 of the suction throttle valve, preferably to the upper and/or left outer side of the top housing part 8. It is particularly preferred to have all bores in the top housing part 8, so that two options exist for the control pressure connections described as actually used in this way. The openings for the unnecessary pressure connections can thus be closed pressure-tightly.

Alternatively or additionally to the possibilities mentioned so far, it is also possible to use a mechanically or electromechanically operated actuator, such as a proportional magnet or a servomotor, in order to adjust the position of the valve piston 124 or to influence the suction opening 18 by adjusting the opening width of the suction throttle valve.

The embodiments described may be combined with each other. For example, one useful combination is the use of a return spring and a proportional magnet, which application produces a resultant force on the valve piston 124 that counteracts the force produced by the high pressure pHD acting on the valve piston 124. Such a combination achieves that the inline piston pump operates with a varying characteristic curve, that the required constructional size of the proportional magnet is reduced, that the electrical power introduced for supply is reduced, and that a possible solution for safeguarding is provided, i.e. that the inline piston pump 1 enters a safe operating state in the event of a failure of the proportional magnet, for example in the event of a cable failure.

Fig. 11 shows a further embodiment of an in-line piston pump 1 using the invention. At the working output of the inline piston pump 1 there is an oil pressure sensor 104. Preferably, however, a multifunctional sensor for detecting oil pressure, oil temperature and oil quality may also be installed. It is particularly preferred that the oil pressure sensor 104 or the multifunction sensor has an interface to the controller 100.

In this case, the individual sensor raw signals are rectified by means of a rectifier 102 into a measurement signal, which is forwarded to the controller 100, for example as a PWM signal or as a function of analog/digital conversion, via a data bus. The controller 100 obtains further measured parameters such as the rotational speed of the main drive 50 or parameters enabling the calculation of the rotational speed. Optionally, the controller 100 obtains further measured and operational parameters, but also from other controllers and/or sensors, for example NOx exhaust gas production from exhaust gas after-treatment. Furthermore, the controller 100 may have an access function to determine the production, or the production, for example the efficiency and emission characteristics of the internal combustion engine 50, may be read at the controller. Direct or indirect control of at least one such actuator 101 (e.g. a servo motor) can be effected via the controller 100, which actuator can adjust the opening width of the suction throttle or in general produce a control of the device 12. Alternatively, the controller 100 may control other actuators. In particular, the controller 100 may be the master driver 50, since a large part of the data related to the embodiment is always essential to the latter.

The coupling of the control actions of the internal combustion engine 50 and the inline piston pump 1 offers many advantages, both for the action carried out by the entire control unit 100 and for the action carried out by different control units, which are coupled to one another by information technology. The mechanical power to be supplied to the inline piston pump 1 (thus providing the necessary hydraulic power or enabling the required volume flow) can be provided by the internal combustion engine 50 along its speed-torque characteristic with the highest efficiency, or along the speed-torque characteristic with the smallest discharge volume, or along the optimized speed-torque characteristic (which takes into account the relatively high efficiency and low discharge volume in the particular case); or strictly comply with its own emission limits (at least in compliance with or strict to exhaust regulations) and maximize efficiency by utilizing the existing allowed space. The advantage of this arrangement is that the optimization can be dynamically matched to various environmental conditions. The usual operating conditions, in which such dynamic optimization is particularly advantageous, are under boundary conditions during operation of the internal combustion engine 50, in which the exhaust gas aftertreatment has not yet reached its operating temperature and therefore does not function in the full range. It is advantageous under such operating conditions to minimize the production of untreated emissions from the operation of the device. After the operating temperature of the exhaust gas aftertreatment is reached, the speed-torque characteristic of the internal combustion engine is shifted to a higher efficiency.

A further improved optimization of this approach is achieved if the efficiency characteristic of the inline piston pump 1 is also used as a parameter set in the control unit 100.

If a change occurs in the hydraulic system, which change effects a strong change in the output value of the in-line piston pump 1 in a very short time, i.e. oil volume flow and/or oil pressure, this information is immediately available to the control function of the internal combustion engine 50. Finally, the respective actuator (e.g. fuel injector) of the internal combustion engine 50 has been controlled simultaneously with the valve piston 124 of the intake throttle valve of the inline piston pump 1. In this connection, a delay in the intervention of the control function of the internal combustion engine 1 can be avoided, which first reacts, for example, to an undesired speed change in its own angle.

Instead of (i) a particularly rapid control of the suction throttle valve, which leads to a relatively high rotational speed of the internal combustion engine 50 when seeking a substantially high hydraulic output and considerably extends the time interval until the rotational speed again approaches its setpoint value (the wording: turbine bore), or (ii) a relatively slow control, which does not make full use of the power of the internal combustion engine 50 and thus unnecessarily slows down the power of the application of the internal combustion engine-hydraulic drive system, a respectively optimized, mutually determined control of the suction throttle valve and of the actuator of the internal combustion engine 50 can be achieved by said coupling. For example, in the case of a specific power increase, in the case of a still low oil temperature of the hydraulic oil, this solution enables a slower control of the suction throttle valve than in the case of an operating temperature of the hydraulic oil which has been reached. In particular, in the case of deeper temperatures of the exhaust gas aftertreatment system (which temperatures are not only at and immediately after the start of cooling, but also after a longer idling phase), the exhaust gas limit values to be maintained can be used in a defined manner for the power of the internal combustion engine 50.

FIG. 12 shows a schematic view of an inline piston pump of the present invention having two discharge passages fluidly separated from each other.

In this case, it is provided that the high-pressure duct 17 can be divided into at least two high-pressure ducts 17, which can in turn be sealed off from one another in a sealed manner. Each high-pressure channel 17 x, 17 x can respectively convey the fluid generated by at least one plunger unit under high-pressure conditions, wherein the high-pressure channels are connected to different plunger units. The partial volume flows (generated by individual plunger units or plunger unit groups separated from one another on the high-pressure side) V1, V2, V3, V4 are not all fluidically connected to one another here downstream of the plunger units, but are separated from one another in terms of flow by the channel separator 171, which effects a division of the high-pressure channel 17 into high-

pressure channels

17, 17.

Each such high pressure channel leads out at least one opening 120, which may serve as a high pressure connection.

It is possible to design

pistons

3, 3', 3 ″ with different diameters so that different requirements of the consumers to be connected can be taken into account.

Fig. 13 shows a schematic diagram in which a switching valve 72 is connected to the high-

pressure outlets

120, 120 of the inline piston pump 1 having

pistons

3, 3', 3 ″ of different diameters, said switching valve connecting the high-

pressure outlets

120, 120 of the inline piston pump 1, which are separate from one another, to one another when not in use. The volume flow Q can thus be any combination of the individual output volume flows of the high-pressure outlets 120, so that a very high variability of the volume flows can be achieved.

In this regard, the switching valve 72 may also be controlled by a telemetry data exchange 73. Basically, the three high-

pressure inlets

92, 93, 94 of the valve 72 are in fluid connection with the respective high-

pressure outlets

120, 120 of the inline piston pump 1 and are joined to one another inside the switching valve 72 and are provided at the high-pressure collecting outlet 95.

The following are other aspects of the invention:

1. an in-line piston pump (1) comprising:

a drive shaft (2) for driving the pump (1),

at least two pistons (3) operatively connected to the drive shaft (2), which are arranged along the drive shaft axis (4) and are each arranged so as to be able to reciprocate in a piston chamber (5),

a base housing part (6) for accommodating the drive shaft (2) and for inserting at least two pistons (3) into respective accommodating recesses (7), and

a top housing part (8) for resting on the base housing part (6);

it is characterized in that the preparation method is characterized in that,

the contact area (9) produced when the top housing part (8) is placed on the base housing part (6) extends over a surface, preferably a layer, which exposes the piston chamber (5) of either the at least two pistons (3).

2. The pump 1 according to aspect 1, wherein the contact region (9) is configured such that, at the base housing part (6) and the top housing part (8) separated from each other, the piston (3) and at least one pressure valve (10), preferably in the form of a high-pressure check valve, can be inserted in the base housing part (6); at least one suction valve (11) can be inserted into the cover housing part (8).

3. The pump 1 according to any of the preceding aspects, wherein the drive shaft (2) is embodied as a camshaft with a single-lobe cam or a multi-lobe cam, as a crankshaft or as an eccentric shaft.

4. The pump 1 according to any of the preceding aspects, wherein the drive shaft axis (4) extends parallel to the level formed by the contact area (9).

5. The pump 1 according to any of the preceding aspects, furthermore has at least one suction valve (11) which is arranged in the top cover housing part (8) and preferably does not project beyond the contact region (9) in the mounted state.

6. The pump 1 according to aspect 5, wherein the suction valve (11) and the piston (3) of each plunger unit have the same longitudinal axis.

7. The pump 1 according to one of the preceding

aspects

5 or 6, wherein, for accommodating the at least one suction valve (11), the respective longitudinal direction of the bore extends perpendicular to the level formed by the contact region (9).

8. The pump 1 according to one of the preceding aspects 5 to 7, wherein the top cover housing part (8) comprises a plurality of suction valves (11) arranged adjacently in parallel.

9. The pump 1 according to any of the preceding aspects, further having at least one high-pressure check valve (10) which is arranged in the base housing part (6) and preferably does not project beyond the contact area (9) in the mounted state.

10. The pump 1 according to aspect 9, wherein the longitudinal axis of the piston (3) of each plunger unit and the longitudinal axis of the high pressure check valve (10) are located on a level, preferably running perpendicular to the drive shaft axis (4).

11. The pump 1 according to one of the preceding

aspects

9 or 10, wherein the base housing part (6) comprises a plurality of parallel adjacently arranged high pressure check valves (10).

12. The pump 1 according to any of the preceding aspects, wherein, for accommodating the piston (3), the respective longitudinal direction of the piston chamber (5) extends perpendicular to the plane formed by the contact area (9) and preferably radially away from the drive shaft axis (4).

13. The pump 1 according to any of the preceding aspects, wherein the piston (3) has a pin (31) which in the mounted state exceeds the level formed by the contact area (9) and preferably projects into a recess (14) and preferably into a spring chamber of a pressure spring (16) of the suction valve (11) acting on the centering unit (15), wherein the recess comprises the suction valve (11) of the same plunger unit.

14. The pump 1 according to any of the preceding aspects, further having means (12) for adjusting or controlling the pump (1), preferably arranged in the top housing part (8).

15. The pump 1 according to aspect 15, wherein the means (12) for adjusting or controlling the pump (1) is a suction throttle valve (121), which is preferably arranged with its longitudinal axis arranged parallel to the drive shaft axis (4).

16. Pump 1 according to any of the preceding aspects, pump (1) according to the preceding claims, wherein the pump (1) comprises three mutually separated housing parts (6, 8, 13), preferably only three mutually separated housing parts (6, 8, 13), i.e. a base housing part (6), a top housing part (8) and a mounting flange part (13).

17. Pump 1 according to aspect 16, wherein the base housing part (6) comprises at least one outlet (20) for the high-pressure connection, a high-pressure check valve (10), a drive shaft (2), at least one drive shaft bearing and a recess (7), whose wall faces are respective guides for the piston (3), or whose wall faces accommodate a piston (3) running bushing,

the head housing part (8) comprises at least one suction connection (18) and a suction valve (11), an

The mounting flange part (13) is used for leading the driving shaft (2) out of the interior of the pump (1).

18. The pump 1 according to

aspect

16 or 17, wherein the drive shaft (2) is supported via a mounting flange part (13) which is sealingly introduced into the housing opening of the base housing part (6), so that the drive shaft (2) can be fitted from this side through the housing opening of the base housing part (6) for the mounting flange part (13).

19. The pump 1 according to one of the preceding aspects 16-18, wherein the base housing member (6) has at least two perforated fixing flanges aligned with one of the pairs of corresponding fixing holes in the mounting flange member (13) so as to achieve a rotational fixing of the base housing member (6) on the mounting flange member (13) around the drive shaft (2).

20. Pump 1 according to one of the preceding

aspects

16, 18 and/or 19, wherein, in addition to having an opening that can be reduced by a mounting flange part (13), the base housing part (6) has a further opening for the drive shaft (2) to be guided out of the interior of the pump (1), the mounting flange part (13) being a cover part that can be fastened to the base housing part (6) in order to cover a drive shaft section guided out of the interior of the pump (1), wherein preferably the base housing part (6) and the cover part are designed, when the cover part is removed, in such a way that the drive shaft (2) is mounted and expanded by the area of the base housing part (6) covered by the cover part.

21. The pump 1 according to any of the preceding aspects, wherein the base housing part (6) is embodied such that the drive shaft (2) is supported on both sides of the base housing part (6) such that a series operation of the pump (1) is achieved without a change of the base housing part (6).

22. The pump 1 according to any of the preceding aspects, wherein the delivery of fluid to the suction valve (11) is guided by a common suction channel extending parallel to the drive shaft axis (4).

23. The pump 1 according to any of the preceding aspects, wherein the suction connection (18) is arranged such that the entire suction channel is elongated, or in a bore which intersects the suction channel at a perpendicular angle.

24. The pump 1 according to any of the preceding aspects, wherein the pumped fluid under high pressure is conducted from the high pressure check valve (10) to the high pressure connection via a common high pressure channel extending parallel to the drive shaft axis (4).

25. The pump 1 according to any one of the preceding aspects, wherein, in each plunger unit, the central axis (71) of the recess (7) for the piston (3) and the central axis of the recess for the high pressure check valve (10) are arranged opposite in an angular range of between 15 ° and 60 °, preferably in an angular range of between 25 ° and 45 °.

26. The pump 1 according to any of the preceding aspects, wherein the sealing element (19) is inserted in a recess of the base housing part (6) and/or in a recess of the top housing part (8).

List of reference numerals

1 in-line piston pump

2 drive shaft

3 piston

3' piston

4 drive shaft axis

5 piston cavity

5' piston cavity

6 base housing part

7 accommodating recess

7' accommodating recess

8 Top cover housing part

9 piston area

10 high-pressure check valve

11 suction valve

12 device

13 mounting flange part

14 concave part

15 centering element

16 pressure spring

17 high pressure channel

18 suction connection

19 sealing element

20 high-pressure connection

21 closure element

22 spring

23 high pressure drilling

31 pin

40 inhalation channel

48 front end drive shaft bearing

49 rear end drive shaft bearing

51 speed sensor

70 frequency converter

71 longitudinal axis

72 switch valve

73 telemetry data exchange

80 hydraulic electric appliance

81 hydraulic unit

Cross section 91

92 high pressure inlet

93 high pressure inlet

94 high pressure inlet

95 high pressure outlet

100 controller

101 actuator

102 rectifier

104 oil pressure sensor

111 suction valve-plunger

120 high pressure outlet

121 has a first longitudinal section with a larger diameter

122 has a second longitudinal section of smaller diameter

123 leak borehole

124 valve piston

125 narrowed part

126 chamfer

127 recess

152 outer annular element

153 internal ring element

154 flange region

155 central recess

158 connecting sheet

171 channel separator

222 spring

223 spring

A sealing member

B sealing element

E1 layer

Q1 volumetric flow

Q2 volumetric flow

Q3 volumetric flow

Sum of Q different volume flows

V1 partial volume flow

V2 partial volume flow

V3 partial volume flow

V4 partial volume flow

Claims

1. An in-line piston pump (1) comprising:

a drive shaft (2) for driving the pump (1),

at least two pistons (3, 3 ') operatively connected to the drive shaft (2) and arranged along the drive shaft axis (4) and in each case reciprocatingly movable in a piston chamber (5, 5'),

a suction connection (18) for conducting the fluid to be pumped, wherein,

a suction valve (11) is arranged in at least one, preferably in each piston chamber (5, 5 ') in such a way that a suction channel (40) connected to the suction connection (18) for the inflow of fluid during a compression movement of the respective piston (3, 3 ') is fluidically separated from the piston chamber (5, 5 ');

it is characterized in that the preparation method is characterized in that,

between the suction connection (18) and a suction channel (40) directly fluidically connected to at least one suction valve (11) there is a device (12) arranged to be able to vary the volumetric flow of the fluid to be pumped between the suction connection (18) and the suction channel (20).

2. The in-line piston pump (1) according to claim 1, wherein the hydraulic device (12) is a valve having a movable valve piston (124) which is arranged with its longitudinal axis preferably parallel to the drive shaft axis (4), wherein the valve is preferably embodied as a suction throttle valve.

3. The in-line piston pump (1) according to any of the preceding claims, wherein the suction throttle valve has a valve piston (124) movable so as to vary the opening degree of the connection of the suction connection (18) with the suction channel (20).

4. The in-line piston pump (1) according to claim 3, wherein the movable valve piston (124) has a flow area which is formed on the longitudinal axis of the piston (124) by a section (122) of narrowed diameter thereof in order to vary the degree of opening of the connection of the suction connection (18) to the suction channel (40), wherein the flow area can preferably be configured as an annular space.

5. The in-line piston pump (1) according to one of the preceding claims 2 to 4, wherein the valve piston (124) is a differential piston and has at least two regions (121, 122) of different diameters, in one of which a flow region is arranged, wherein preferably the at least two regions (121, 122) of different diameters are constructed in two parts.

6. The in-line piston pump (1) according to claim 5, wherein the area (121) provided with a flow area has a leakage channel (123) extending in the direction of movement of the piston (124) so that fluid brought along by the control or high-pressure bore (23) can be led out on the suction side.

7. The in-line piston pump (1) according to one of the preceding claims 2 to 6, wherein the valve piston (124) is supported in its longitudinal direction on the return spring (22) and the valve piston (124) has a working face on which a fluid can be guided via a correspondingly positioned control or high-pressure bore (23) in the respective housing part, wherein the working face is oriented such that a fluid pressure thereon generates a force which is opposed to the restoring force of the at least one return spring (22), wherein the working face is preferably located on the respective end side of the piston (124), and/or wherein the valve piston (124) is held in a first end-abutting position when a pressure level in the control or high-pressure bore (23) is not exceeded, below a determined threshold value.

8. The in-line piston pump (1) as claimed in claim 7, wherein an end of the return spring (22) opposite the valve piston (124) is supported on a closure element (21) mounted in the piston bore and/or the closure element bears against an end for a displacement movement of the piston (124), which is opposite with respect to the end bearing, wherein preferably the closure element is embodied as a locking bolt.

9. The in-line piston pump (1) according to one of the preceding claims 2 to 8, wherein the suction throttle valve is provided with at least one second pressure spring (222) which only acts on the valve piston (124) when the return spring (22) is compressed together with a known length due to a known change in position of the piston (124); and/or the suction throttle valve is provided with at least one second pressure spring (223) which no longer acts on the valve piston (124) when the return spring (22) is compressed together by a known length due to a known change in position of the piston (124).

10. The in-line piston pump (1) according to one of the preceding claims 2 to 9, wherein an adjustable force, which is generated by means of a pressure level brought about by the valve piston (124) via the control or high-pressure bore (23), can be applied to the piston (124), for example by means of a servomotor, a proportional magnet and/or an introduced regulating pressure, which force opposes the force.

11. The in-line piston pump (1) according to one of the preceding claims 2 to 10, wherein the control or high pressure bore (23) is in fluid connection with the high pressure outlet (17) of the in-line piston pump (1), wherein preferably via a hydraulic unit (81) which is capable of generating a reduced pressure level from the high pressure outlet (17) of the in-line piston pump (1), which pressure level is preferably predetermined by telemetry data exchange.

12. The in-line piston pump (1) according to any of the preceding claims, wherein the drive shaft (2) is embodied as a camshaft with a single-lobe cam or a multi-lobe cam, as a crankshaft or as an eccentric shaft.

13. The in-line piston pump (1) according to any of the preceding claims, wherein the drive shaft (2) is driven via a main drive (50), preferably embodied as an internal combustion engine and/or as an electric motor; the torque of the drive shaft (2) provided by the main drive (50) is preferably guided via a gear mechanism.

14. The in-line piston pump (1) according to any of the preceding claims, wherein a rotational speed signal is provided in fixed relation to the rotational speed of the drive shaft (2), which is fed back to the control means and/or the regulating means; and/or a pressure signal which, in a fixed relationship to the high pressure level of the in-line piston pump (1), represents in particular the pressure level at the high pressure channel (20) or the high pressure outlet (17), said pressure signal being fed back to the control and/or regulating device; and/or a pressure signal which, in a fixed relationship with the pressure level in the suction region, represents in particular the pressure level at the suction connection (18) or in the suction channel (40), which pressure signal is fed back to the control and/or regulating device.

15. The in-line piston pump (1) according to any of the preceding claims, wherein the flows of the fluid to be pumped generated by the individual pistons (3, 3', 3") are not completely united with each other downstream, but are led out of the in-line piston pump (1) via at least two separate high-pressure outlets (102, 120).

16. The in-line piston pump (1) according to any of the preceding claims, wherein at least two pistons (3, 3', 3") have different diameters.

17. The in-line piston pump (1) according to claim 15 or 16, wherein the flow generated by each piston (3, 3', 3") of the fluid to be pumped is switched downstream by at least one passage separator (171) arranged in an optional manner, which is inserted into the high pressure passage (17 x ).

18. The in-line piston pump (1) according to one of the preceding claims 15 to 17, wherein a switching valve (72) is provided which brings at least two separate high-pressure outlets (102, 120) exiting the in-line piston pump (1) into or out of association with each other in a selectable manner and gives a volume flow (Q) produced by the association at the collection outlet (94).

19. Method for controlling or regulating at least one output volume flow of an in-line piston pump (1) according to one of the preceding claims, wherein,

the output volume flow is carried out without the device (12) or with a constant adjustment of the device (12) as a function of the rotational speed of the drive shaft (2), in which a pressure loss as low as possible is produced along the suction path, i.e. from the suction connection (18) to the suction channel (40).

20. Method for controlling or regulating the output volume flow of an in-line piston pump (1) according to any of the preceding claims, wherein,

the output volume flow can be varied as a function of the rotational speed of the drive shaft (2) and/or the opening of the device (12) and/or via a switching valve (72).

21. Method for controlling or regulating the power and/or torque of an in-line piston pump (1) according to any of the preceding claims, wherein,

the device (12) can be adjusted by means of an actuator (101) which receives a control signal from a controller (100), the controller (100) preferably receiving at least one second input signal from a further unit which inputs mechanical power to the inline piston pump (1) and/or receives hydraulic power from the inline piston pump (1), and preferably inputs at least one operating parameter of the inline piston pump (1) to the controller (100).