CH716632A1 - In-line piston pump. - Google Patents

Abstract

The present invention relates to an in-line piston pump (1), comprising a drive shaft (2) for driving the pump, at least two pistons (3) which are operatively connected to the drive shaft (2) and which are arranged along a drive shaft axis and each in a piston chamber (5 ) are arranged to be movable back and forth, a base housing part (6) for receiving the drive width (7) and for inserting the at least two pistons (3) into corresponding receiving recesses, and a cover housing part (8) for attachment to the basic housing part. The invention is characterized in that the contact area (9) generated when attaching the cover housing part (8) to the base housing part runs on a surface, preferably in a plane, which exposes the piston chamber of a respective one of the at least two pistons (3).

Description

description

The present invention relates to an in-line piston pump, which is preferably a hydraulic positive displacement pump of in-line piston design. This comprises at least two displacement units which are arranged one behind the other in the direction of the drive shaft axis.

Such pumps are required in a variety of applications, for example. To circulate a coolant circuit of a vehicle, to supply a fan motor, in an oil circulation of an internal combustion engine. Such pumps are also required for use in small devices, e.g. a mini excavator.

DE 197 08 597 discloses a suction-throttled feed pump and shows the use of a suction throttle for a series piston pump.

WO 2010 130 495 A1 discloses an in-line piston pump whose drive shaft is designed as a crankshaft.

In-line piston pumps with a camshaft are also known from the prior art.

It is the aim of the present invention to provide an in-line piston pump that is as inexpensive as possible and offers extensive flexibility for installation and also offers the highest possible power density.

This is achieved with the in-line piston pump which has all the features of claim 1. Such a pump has an advantageously constructed structure and is designed to optimize installation space. Advantageous refinements are set out in the dependent claims.

The in-line piston pump according to the invention comprises a drive shaft for driving the pump, at least two pistons which are in operative connection with the drive shaft and which are arranged along a drive shaft axis and are each arranged to be movable to and fro in a piston chamber, a base housing part for receiving the drive shaft and Insertion of the at least two pistons into corresponding receiving recesses, and a cover housing part for attachment to the basic housing part. The pump is characterized in that the contact area generated when the cover housing part is attached to the base housing part runs in a surface, preferably in a plane, which exposes the piston space of a respective one of the at least two pistons.

Thus, the pump can be mounted particularly easily, since the necessary components, such as pistons or the like, can be inserted in a simple manner through the section of the preferably flat contact surface of the base housing part and the cover housing part.

It can be provided that the contact area is designed so that when the base housing part and cover housing part are separated from each other, an insertion of the piston and at least one pressure valve, preferably in the form of high-pressure check valves, in the main housing part and an insertion of at least one suction valve in the Lid housing part can be done.

According to a further modification it can be provided that the drive shaft is designed as a camshaft with single or multiple cams, as a crankshaft or eccentric shaft.

According to a further optional development of the invention it can be provided that the drive shaft axis runs parallel to a plane formed by the contact area.

It is preferably provided that the pump is further provided with at least one suction valve which is arranged in the cover housing part, and preferably does not protrude beyond the contact area in an installed state.

The suction valve and the piston of a respective displacement unit can have an identical longitudinal axis.

According to a further modification it can be provided that the respective longitudinal direction of the bores for receiving the at least one suction valve extends perpendicular to a plane formed by the contact area.

This facilitates the introduction of the at least one suction valve into the bore provided for this purpose.

Furthermore, it can be provided that the cover housing part comprises a plurality of suction valves arranged in parallel next to one another. The suction valves can each have a corresponding piston or a corresponding recess for a piston in the basic housing part.

The invention also includes the possibility that at least one high-pressure check valve is provided, which is arranged in the basic housing part, and preferably does not protrude beyond the contact area in an installed state.

The high-pressure check valve is in fluid connection with a space that can be reduced in volume by the piston and ensures that no high-pressure fluid flows back during an expansion stroke of the piston.

Preferably, the longitudinal axis of the piston and the longitudinal axis of a high pressure check valve of a respective displacement unit are arranged on a plane which is preferably pierced perpendicularly by the drive shaft axis.

In addition, it can be provided according to the invention that the basic housing part comprises a plurality of high-pressure check valves arranged in parallel next to one another. The side of the valve facing away from a respective space whose volume can be changed represents a common high-pressure line from which fluid conveyed by the pump is discharged.

According to a further modification it can be provided that the respective longitudinal directions of the piston chambers for receiving the pistons run perpendicular to a plane formed by the contact area and preferably extend radially from the drive shaft axis.

According to the invention it can also be provided that the piston has a pin which, when installed, exceeds the plane formed by the contact area and preferably protrudes into the recess which houses the suction valve of the same displacement unit and preferably into the spring chamber of the the centering element engaging compression spring of the suction valve protrudes.

The pump according to the invention can furthermore be provided with a device which is used to regulate or control the pump, which is preferably arranged in the cover housing part.

This device for regulating or controlling the pump can be, for example, a suction throttle valve which is preferably arranged so that its longitudinal axis is arranged parallel to the drive shaft axis.

The inflow of the fluid to be pumped could thus be regulated.

According to the invention it can be provided that the pump comprises three separable housing parts, preferably comprises only three separable housing parts, namely the basic housing part, the cover housing part and a mounting flange part.

It is preferably provided that the base housing part comprises an outlet that can be used for a high pressure connection, the high pressure check valves, the drive shaft, at least one drive shaft bearing and the recesses, the wall surfaces of which are the respective guides of the pistons or the wall surfaces of which are the bushings of the pistons and the cover housing part comprises a suction connection and the suction valves, and the mounting flange part serves to lead the drive shaft out of an interior of the pump.

According to an advantageous embodiment, the drive shaft is mounted on the mounting flange part, which can be inserted sealingly into a housing opening of the base housing part, so that the drive shaft can be mounted from this side through the housing opening of the base housing part provided for the mounting flange part.

Furthermore, it can be provided that the basic housing part has at least two perforated fastening tabs which are aligned with a pair of several pairs of corresponding fastening holes in the mounting flange part, so that there are several mounting options for the base housing part rotated around the drive shaft on the mounting flange part, ie different mounting angles of the ambulatory flange part are possible.

Furthermore, it can be provided according to an advantageous modification of the invention that the base housing part has a further opening for leading out the drive shaft in addition to the opening which can be reduced by the mounting flange part in order to lead the drive shaft out of the interior of the pump, and the mounting flange part is a cover part , which can be fastened to the basic housing part in order to cover a drive shaft section led out from an interior of the pump, with the basic housing part and the cover part preferably being designed with a dismantled cover part so that the drive shaft can be installed or removed through the area covered by the cover part to enable the basic housing part.

According to the invention it can also be provided that the basic housing part is designed such that the drive shaft protrudes on two sides of the basic housing part, so that a tandem operation of the pump is possible without making changes to the basic housing part.

According to the invention, the pump can be designed in such a way that the fluid is fed to the suction valves via a common suction channel running parallel to the drive shaft axis.

According to an optional modification of the invention it can be provided that a suction connection is arranged such that it is an extension of the common suction channel or is arranged in a bore that meets this suction channel at a right angle.

It can also be provided according to the invention that the high-pressure, pumped fluid is guided from the high-pressure check valves to the high-pressure connection via a common high-pressure channel running parallel to the drive shaft axis.

Furthermore, it can be provided according to the invention that in each displacement unit the central axis of the recess for the piston and that of the recess for the high-pressure check valve are in an angular range between 15 ° and 60 ° to one another, preferably in an angular range between 25 ° and 45 °.

According to a further modification of the invention it can be provided that sealing elements are inserted into recesses in the base housing part and / or recesses in the cover housing part.

Further features, details and advantages can be seen from the following description of the figures. Show:

Fig. 1:

a schematic sectional view of the in-line piston pump according to the invention transversely to the drive shaft axis.

Fig. 2:

a schematic sectional view of the in-line piston pump according to the invention along the drive shaft axis,

Fig. 3:

a perspective view of the in-line piston pump according to the invention,

Fig. 4:

a schematic sectional view of the in-line piston pump according to the invention through the cover housing, in which the suction throttle arranged therein is exposed, and

Fig. 5:

a perspective view of a centering element of the in-line piston pump.

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

A displacement unit can be seen which comprises a piston 3 which compresses fluid introduced into a cylinder space and conveys it away via a valve 10. Several displacement units are arranged one behind the other in the direction of the axis of the drive shaft 2. Each piston 3 is arranged radially to the drive shaft axis 2 and is in an operative connection with the drive shaft 2. The in-line piston pump 1 preferably comprises three housing parts 6, 8, 13. The lower housing part 6, which is also called the basic housing part 6, houses the part of the drive shaft 2 located inside the pump, the pistons 3 and the check valves 10 on the high pressure side (outlet valves) of the respective V erding units.

The upper housing part 8, which is also called the cover housing part 8, contains the suction valves 11 (inlet valves). The two housing parts 6, 8 adjoin one another via a flat and preferably a flat contact area 9.

For example, based on a specific drive speed, the pressure fluid delivered by the pump 1 can be adapted with a control and / or regulating device 121 by limiting the intake-side inflow of the pressure fluid to the pump 1. The pump 1 has an advantageously constructed structure and is designed to optimize installation space.

As can also be seen from FIG. 1, the piston 3 is received in a reciprocating manner in a piston chamber 5, which is arranged in parts in the cover housing part 8 and the base housing part 6. In the exemplary embodiment, the piston 3 has a centrally arranged pin 31 which protrudes into the cover housing part 8. The movement of the piston 3 takes place due to the rotation of the drive shaft 2, so that the piston 3 moves up and down in the piston chamber 5.

The mounting flange part 13 can also be seen, with which the pump 1 can be attached to an element not shown.

The operation of the pump 1 is as follows. First, a fluid to be pumped flows through the suction valve 11 into the piston chamber 5, since the piston 3 moves on the way from the top to the bottom dead center. The spring 32 supported on the piston 3 ensures a movement of the piston 3 towards the bottom dead center, so that a continuous operative connection between the piston 3 and the drive shaft 2 is ensured. The piston movement increases the size of the piston chamber 5, so that the suction valve 11 is moved into its open position against the biasing force of the compression spring 16, which means that the fluid to be pumped penetrates or is sucked into the piston chamber.

When the piston 3 moves from bottom to top dead center, the pressure in the piston chamber 5 increases, the suction valve closes and the fluid under high pressure is conveyed via the outlet valve 10 to the high pressure side of the pump 1.

Fig. 2 shows a sectional view in the longitudinal direction of the drive shaft 2, from which one can see the arrangement of the displacement units. Several pistons 3 are arranged one behind the other in the longitudinal direction of the drive shaft 2 and each interact with a specifically shaped section of the drive shaft 2, so that the fluid is approximately continuously conveyed.

It can be seen that the shown three displacement units arranged one behind the other are connected upstream to a common suction line, from which the fluid to be conveyed is conveyed into the associated piston chamber 5 via a respective suction valve 11. An opening to the suction line is closed by means of an element of the suction valve via spring force, so that no fluid can be introduced into the suction line when the piston 3 moves from bottom dead center to top dead center.

The compression spring 16, which acts on the centering element 15 which is rigidly arranged in the piston chamber 5, ensures this effect. In addition, a further compression spring 32 acts on the centering element 15, which permanently urges the piston in the direction of the drive shaft 2.

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

2 also shows the presence of a mounting flange part 13 which closes the opening of the base housing part 6 for inserting the drive shaft 2 and at the same time leads a section of the drive shaft 2 to the outside.

It can be provided that the mounting flange part 13 is the only passage for part of the drive shaft 2, a development with two passages of the drive shaft 2 on opposite sides of the base housing part 6 is also covered by the invention. As a rule, one of the two leadthroughs is then formed in one piece with the basic housing part, whereas the other leadthrough is implemented by the mounting flange part 13.

The advantage of two leadthroughs in the drive shaft 2 is that tandem operation of the pump 1 can be implemented without any further effort, since a subsequent pump stage can be coupled to the drive shaft 2 that has already been driven out.

3 shows a perspective view of the pump 1, by means of which the three-part housing structure can be seen. The cover housing part 8 is placed on the base housing part 6, which in turn is connected to the mounting flange part 13.

The high-pressure connection 20 of the pump 1 can be arranged on the base housing part 6 on a side of the pump 1 opposite the mounting flange part.

According to an alternative configuration, the mounting flange part 13 with respect to the embodiment of FIG. 17 can also be arranged on the same side as the high-pressure connection 20, the drive-side drive shaft section then being guided to the outside through an opening formed in one piece with the base housing part 6 and the mounting flange part 13, in a state attached to the base housing part 6, covers the output-side part of the drive shaft 2 or - in a dismantled state - exposes it for tandem operation of the pump.

4 shows a plan view of a sectional plane 91 arranged in the cover housing part 8, in which the feed bores 7 to the suction valves 11 can be seen. These three supply bores 7 are connected to the suction line, which is in fluid connection with the suction connection as a function of a position of a suction throttle valve 121. The suction throttle valve 121 can influence the inflow amount of the fluid to be conveyed into the suction line as a function of its position.

The suction connection 18 does not have to be arranged on a side wall of the cover housing part 8, as shown, but can also be located on its upper side. It is also possible for several openings to exist, one of which is used as a suction connection 8 and all of the others of these openings can be closed. This opening is preferably located or these openings are located on the side wall and / or the top of the housing part 8.

5 is a perspective view of the centering element 15, which comprises an inner ring element 153 and an outer ring element 152, the inner ring element 153 and the outer ring element 152 being arranged coaxially with one another. The two ring elements 152, 153 are connected with a connecting web 158, the inner ring element 153 having an inwardly directed flange area 154 on which the compression spring 16 for the valve stem rests. The central recess 155 can be pierced by a pin 31 of the piston 3 with a corresponding stroke.

It should also be noted that the drive shaft 2 can be designed as a crankshaft or eccentric shaft, the pistons 3 then being in an indirect operative connection to it. If the drive shaft 2 is designed as a camshaft, a direct operative connection is preferred for reasons of cost. A direct connection means that the end face of a piston 3 directly touches its opposite cam. A roller, less preferably a ball bearing or possibly also a sliding element, via which rolling or sliding takes place on the rotating cam, can be attached to the piston 3. Then there is an indirect operative connection between the piston 3 and the drive shaft 2.

For better readability, the term oil is used in the following explanations, in particular for terms derived therefrom such as oil pressure, oil flow, oil quantity, oil storage tank, oil dead volume, oil compression, etc.

Each displacement unit comprises, on the inlet side, a suction valve 11, preferably designed as a check valve, a piston 3 and, as an outlet valve, a check valve 10 on the high pressure side. The in-line piston pump 1 shown in the figures has three displacement units and is equipped with a camshaft 2 which has double cams (see FIG. 1). The three displacement units convey the - this can be oil - to a common high-pressure connection of the in-line piston pump.

A compression spring 32 ensures that the piston 3 is supported on the cam opposite it even in suction operation. Since the embodiment is double cams, two lifting and lowering operations of the piston take place when the drive shaft 2 is fully rotated. If, in the course of the camshaft rotation, a piston under consideration moves from TDC (top dead center) in the direction of BDC (bottom dead center), the increase in volume of the displacement chamber 5 of the displacement unit under consideration results in a vacuum. Due to the higher oil pressure on the suction side, the suction valve 11 opens, whereby an oil flow leaves the oil storage tank and into the displacer

space of the displacer unit under consideration begins flowing into it. After BDC has been exceeded (bottom dead center), the volume of the displacement chamber 5 is reduced as a result of the piston continuing to plunge further into its piston bore. The resulting increase in pressure of the amount of oil enclosed in this volume leads to the suction valve 11 closing. After a further increase in pressure, the check valve 10 opens on the high pressure side. The two check valves of a respective displacement unit also ensure that different displacement units do not interfere with one another; in order to prevent the oil brought to the high pressure level by a displacement unit from reaching the suction side via an adjacent displacement unit.

The use of an eccentric or crankshaft would also result in the analogous operative relationships between the piston movement and the switching states of the two check valves of a displacement unit.

The components introduced into the housing for the suction valve 11 and the piston 3 of a displacement unit preferably all have an imaginary common longitudinal axis 71 which is aligned radially with the drive shaft axis 4 (see FIG. 2).

These are the following components: a piston 3, a compression spring 32, a valve stem, a compression spring 16 and a centering element 15. The longitudinal axis 71 is also the longitudinal axis of those bores 5, 7 in the housing parts 6, 8, in which the named components are housed.

The valve stem of the suction valve 11 can resemble the shape of a thimble. The piston 3 can be guided along its lateral surface in the piston bore 5 and is preferably designed as a hollow piston. In a particularly preferred embodiment, it has a central pin 31 on the side facing away from the drive shaft 2, the length dimension of which exceeds that of the piston wall. As a result, there is an annular space in the interior of the piston 3 in which part of the compression spring 32 is located. The lower end of the annular space ends on the inner bottom of the piston 3 on which one end of the compression spring 32 is supported. The area of the compression spring 32 facing away therefrom protrudes beyond the open top of this annular space. The end of the compression spring 32 there is supported on the centering element 15. An embodiment of such a centering element 15, recognizable in its details, can be seen in FIG. 5 and is explained in the following text. When the compression spring 32 is compressed to its minimum length, which is possible in its installed state, it can be that it is almost completely in the annular space. The cross-sectional area of the annular space must be dimensioned correspondingly large in order not to disturb the movement of the compression spring 32, but should otherwise be as small as possible in order to limit the dead oil volume as much as possible.

The shaft-shaped section of the suction valve plunger has an inner diameter which is matched to the outer diameter of the inner wall 153 of the centering element 15, as a result of which the suction valve plunger is guided. On the inside of the inner wall 153 of the centering element 15 there is a shoulder or a support surface 158 on which the compression spring 16 can be supported. The opposite end of the compression spring 16 is supported on the bottom of the blind hole of the suction valve stem. The spring constant of the compression spring 16 is significantly smaller than that of the compression spring 32. The compression spring 16 must be compressed to a corresponding extent at the only slight negative pressure that is generated when the volume of the displacement chamber increases compared to the pressure level prevailing in the oil storage tank in order to release the flow cross-section at the suction valve 11. As already mentioned, the compression spring 32 must ensure by means of a correspondingly high restoring force that the stamp surface of the piston 3 is also pressed onto the cam contour in the BDC position.

When the in-line piston machine is in operation, the piston 3 and the suction valve stem move in the direction of the imaginary longitudinal axis 71.

In a preferred embodiment, the pin 31 of the piston 3 is designed in such a way that in the TDC position it fills as large a proportion of the remaining blind hole volume of the suction valve stem as possible (cf. FIG. 1). As a result, the partial volume alternately filled by pin 31 and not filled in the blind hole of the suction valve plunger 11 contributes to the oil compression. Furthermore, a pin end located near the bottom of the blind hole of the suction valve plunger favors the rapid closing of the suction valve when the piston 3 moves from BDC in the direction TDC.

Three forces act on the plunger of the high pressure check valve 10 (see FIG. 1). The plunger provides a support surface for the oil pressure level at the high pressure connection of the in-line piston pump 1. The restoring force of its compression spring acts in the same direction, i.e. in the blocking direction of the check valve 10. As soon as the oil pressure in the oil compression chamber under consideration is large enough, the force acting in the flow direction of the check valve 10 is large enough to open it. As long as the check valve 10 is open, this displacement unit provides hydraulic power that is output via the high-pressure connection 20 of the in-line piston pump 1.

The plunger guidance on the high-pressure check valve 10 takes place in the same way as in the case of the suction valve 11. In contrast to the suction valves 11 built into the housing 8, an additional component according to FIG. 1 must be inserted into the housing 6 for the high-pressure check valves 10 be installed so that the high pressure check valves are high pressure tight in the blocking direction.

For each displacer unit there is a sectional plane through which a central longitudinal section through the piston 3 is exposed at the same time as a central longitudinal section through the suction valve 11 and also a central longitudinal section through the high pressure check valve 10. This cutting plane and the axis of the drive shaft 2 are perpendicular to one another.

In each displacement unit, the central axis of the bore 5 for the piston 3 and that of the bore for the high-pressure check valve 10 are in an angular range between 15 ° and 60 ° to one another. An angle range between 25 ° and 45 ° is preferred.

Sharp angles allow a small width dimension of the in-line piston pump 1 and up to a certain extent an increase in the power density of the in-line piston pump 1 and, which may be decisive for the ability of the in-line piston pump 1 to be attached to a specific drive arrangement, e.g. to a power take-off of an internal combustion engine or to a Multi-circuit unit, but require a stronger deflection of the oil drain of the oil brought to the high pressure level. Therefore, particularly acute angles are unfavorable, since the strong deflection leads to high pressure losses. Particularly acute angles are also unfavorable because the overall height of the in-line piston pump increases.

The centering elements present in the valves 10, 11 make a significant contribution to ensuring that the design of the in-line piston pump 1 shown as an exemplary embodiment can be kept simple.

The exemplary embodiment of a centering element 15 shown in perspective in FIG. 5 also has a comparatively simple structure. The bottom is in the form of a circular disc which has two kidney-shaped openings and a centrally placed circular opening 155. Furthermore, the centering element has two wall areas 153, 152 in the form of concentric circles. As can be seen, such a centering element 15 can be manufactured from a round material for the most part as a turned part using a single clamping process. Only the kidney-shaped openings have to be made in some other way, for example by milling.

In the exemplary embodiment, two centering elements 15 (one for each valve 10, 11) are used per displacement unit. In its generic design, the centering element 15 used in the area of the suction valve 11 can be designed in exactly the same way as the centering element 15 used in the high-pressure check valve 10 of the suction valve 11, since smaller flow cross-sections in the suction area, ie in the low-pressure area, are much less noticeable than in the high-pressure area.

The two kidney-shaped areas in the perspective view of a centering element shown in FIG. 5 are each part of the flow cross-section and represent a local constriction along the flow path. As can easily be seen, a reduction in the outer diameter of the centering element 15 results in the same all other dimensions independent of this lead to a decrease in the two kidney-shaped flow cross-sections.

The housing preferably consists of a base housing 6 and a cover housing part 8 and a third housing part 13 (see FIG. 2).

The housing part 6 can approximately have the shape of two composite geometric base bodies, namely that of a cylinder and that of a cuboid. In this embodiment, the drive shaft 2 and its mounting - exactly one mounting in the exemplary embodiment - are located in the interior of the cylindrical sub-area, whereas the inner volume of the cuboid sub-area houses the pistons 3 and the high-pressure check valves 10 and the high-pressure connection 20 of the in-line piston pump 1.

The cover housing part 8 can approximately have the shape of a cuboid. The suction connection 18 is located thereon and the suction valves 11 are located in the inner volume of the cover housing part 8. Furthermore, part of the device which is used to regulate or control the in-line piston pump 1 can be accommodated in the cover housing part 8. With respect to the suction valves 11, such a device is preferably arranged on the side facing away from the housing part 6. Such a device is preferably a suction throttle valve. The embodiment shown in FIG. 4 shows only a preferred embodiment of the control piston 121 used for the suction throttle and inserted in its bore. Suction throttle valves are generally known to those skilled in the art.

The housing parts 6 and 8 touch one another directly via a flat contact 9 or indirectly contact each other via a sealing system 19. It is particularly preferred to have a flat contact that lies on a plane that runs parallel to the drive shaft axis 2. In the sense of the mathematical description, a vector along the central axis of one or each piston bore is very particularly preferably a vector normal to the plane 9.

In a first variant of the pump housing, the cylindrical section of the basic housing 6 has no cover surface on the side on which the drive shaft 2 is guided out through the pump housing.

The closing of the pump housing there is incumbent on the housing part 13, which has the design of a mounting flange and rests flat on the end face of the cylinder wall of the housing part.

On its exit side from the housing part 6, the drive shaft 1 is guided to the outside in a central longitudinal opening through the flange-shaped housing part 13 and is supported along this area (see FIG. 2).

In the case of the basic housing part 6, the closed cover side of the cylindrical partial area is shaped in such a way that the built-in drive shaft 2 is received via a bearing attached directly to it. At least in such in-line piston pumps 1 with a comparatively small number of pistons, no further drive shaft bearings are necessary. As

Drive shaft bearings can be roller bearings or slide bearings. Preference is given to slide bearings that can absorb radial and axial forces and are referred to as flange bearings.

By correspondingly tapering the diameter at the longitudinal ends of the drive shaft 2 in the housing part 6 and 13, a bearing with axial fixation of the drive shaft 2 can be achieved in a simple manner.

The seal between the mounting flange part 13 and the base housing part 6 is carried out with a seal B, for example an O-ring. The seal between the mounting flange part 13 and the drive shaft 2 is made with a seal A, e.g. with a sealing ring with a sealing lip (see Fig. 2).

The flange-shaped housing part 13 can be fastened to the housing part 6 via several perforated tabs located thereon, the bearing surfaces of which end flush with the cylinder wall on a plane.

The cuboid area of the housing part 6 is designed in such a way that it encloses only the smallest possible circumference of the cylindrical area. The hole pattern of said tabs can be transferred in the form of prepared holes when the housing part 13, i.e. the pump flange, is poured.

In an advantageous embodiment, the said hole pattern can be applied several times to the circumference of the pump flange 13. In this way, a series piston pump 1 is provided, which can also be installed in other than the originally / mainly intended installation position without a great deal of additional effort. The in-line piston pump 1 can be adapted to different installation situations by adapting a single component, namely by modifying the flange (the housing part 13) or selecting a different flange type, whereas all other components of the in-line piston pump can be retained unchanged. (For example, instead of the embodiment shown in the figures in which an SAE-A flange is present, an SAE-B flange could be used.)

For the housing part 6, it can be advantageous if the cylindrical housing area in the end area of its closed longitudinal end is geometrically wider than the mounting of the drive shaft 2 requires. If such additional installation space is available, the corresponding cover surface at the longitudinal end of the housing part 6 can be removed and a further in-line piston pump can be added, i.e. a tandem arrangement of two in-line piston pumps can be shown. The modification to the housing part 6 relates to the addition of a further housing of an in-line piston pump. The coupling of the drive units of both hydraulic pumps can take place, for example, via a drive shaft toothing. Instead of a structurally identical in-line piston pump, a rotary drive of a completely different hydraulic pump, an air compressor or an electric machine, etc. can of course also be shown.

If the pump housing is constructed as described above, aluminum or an alloy containing aluminum is preferably used for the housing part 13.

In a further variant, which is not shown in any figure, the entire flange area of the in-line piston pump 1 is located directly on the housing part 6, which although the flexibility to adapt to different installation space conditions greatly restricts, but simplifies the housing parts 6 and 13 . In this variant, the entire wall area up to the passage opening of the drive shaft 2 is part of the housing part 6. In contrast, the cover surface of the cylindrical housing area arranged opposite thereto can be closed off with the housing part 13. The opening of the housing part 6 to be closed by the housing part 13 is expanded enough that the drive shaft (camshaft or eccentric shaft) can be inserted through this opening during assembly. In this variant, the housing parts 6 and 13 are expediently designed in such a way that the housing part 6 is already prepared for the creation of a through-drive of a second in-line piston pump for tandem operation.

Of course, it would be conceivable that the in-line piston pump according to the invention in a third variant, for which there is also no figure, does not have a completely separate housing, but part of its casing is already a component of another housing, ie the in-line piston pump 1 according to the invention would be used as a Built-in pump can be used. Apart from the changes directly affected by this, the other features described are also considered advantageous here; in particular the retention of what is described in the following paragraph.

The separation point between the lower housing part 6 and the upper housing part 8 is preferably set so that the suction valves 11 are as completely as possible in the upper housing part 8, whereas the actual piston 3 and the high-pressure check valves 10 are as completely as possible in the lower one Housing part 6 are located. For the reasons mentioned above, the pin 31 located on the piston 3 protrudes into the housing part 8. Such an arrangement offers the advantage that the named components or subassemblies are easily accessible for assembly / disassembly and can be brought into their respective installation end positions in the housing parts 6 and 8 with good accessibility or can be easily removed therefrom.

The separation point between the lower housing part 6 and the upper housing part 8 is particularly preferably set so that the suction valves 11 are completely located in the upper housing part 8, whereas the pistons 3 and the high-pressure check valves 10 are completely located in the lower housing part 6 are located. If the contact surface of the piston walls is only located in the housing part 1, the finishing of these contact surfaces is clearly limited to this housing part. The aforementioned division of the housing parts 6 and 8 offers the advantage that the contact surface for the upper side of the suction valve plunger 11 can be incorporated directly into the housing part 8, although the dimensional accuracy and the surface quality of the said contact surfaces must be sufficiently good so that the the suction valves

Claims (26)

11 are sealed high-pressure-tight in the blocking direction. If a corresponding special drill is available, this contact surface can be manufactured in one operation together with the recess in which the centering element 15 is mounted. When assembling or dismantling a series piston pump 1 according to the invention, the two housing parts 6 and 8 are positioned in such a way that their surface, which is located on the plane 9 in relation to the assembled series piston pump 1, is exposed and from this side coming the assembly or disassembly of the suction valves 11, the pistons 3 and the high pressure check valves 10 can be carried out. Thanks to such a housing structure, good assembly accessibility with the corresponding consequential advantages is achieved. Instead of sealing all the separation points between the housing parts 6 and 8 by discrete seals, such a sealing system 19 is preferably inserted in the contact surface between the housing parts 6 and 8, which several individual seals or at least one individual seal and at least one further structural element with which Has additional functions related to sealing. The structural elements can be seal support elements and control elements for visual and / or haptic control of the installation position and / or installation orientation. The individual seals and structural elements are preferably applied to a seal carrier which is installed as a whole when the in-line piston pump is installed. The sealing system can contain positioning elements that make incorrect installation impossible or at least allow it to be recognized from the outside. The in-line piston pump 1 can have at least one bore which can be used as a suction connection 18 and which is preferably located on the upper housing part 8. A suction connection 18 can, as shown in FIG. 4, be arranged in such a way that the oil connection meets the suction channel perpendicularly through a bore extending from a longitudinal side wall or the wall located diametrically to the housing part 6. If there is a suction throttle valve in the housing part 8, the suction channel and the bores, one of which can be used to accommodate the suction connection and the one for accommodating the suction throttle valve, are preferably arranged in such a relative position to one another that the bore of the suction connection that meets the suction channel is perpendicular from the hole to accommodate the suction throttle valve (see. Fig. 4). To achieve greater flexibility for the attachment or installation of the in-line piston pump 1, additional openings can be provided so that there is a certain flexibility for attaching the suction connection. Such a possibility would be, for example, the arrangement of a further opening, the axis of which is parallel to the respective piston movement directions of the in-line piston pump. Clearly, one of these openings is then used as a suction connection and the other openings must be sealed. The in-line piston pump 1 has at least one bore that can be used as a high-pressure connection 20, which is preferably located on the lower housing part 6. A placement of a high-pressure connection 20 that can be implemented with little effort is the continuation of the high-pressure channel 17 to be seen in FIG. 1 to the outside, as can be seen in FIG. 3. An alternative or additional placement is a bore starting from the longitudinal side wall of the housing part 6 and meeting the high-pressure channel. Openings that are not required for further suction and high-pressure connections can or must be closed in a pressure-tight manner. Being able to choose between different openings makes it easier to adapt the in-line piston pump to different accessibility and installation space conditions. Equally, the possibility of choosing one of different openings to be able to use as a high pressure connection facilitates the adaptation of the in-line piston pump 1 to different accessibility and installation space conditions. To remove the leakage from the housing area 6 in which the drive shaft 2 is located, an oil connection can extend from there to the suction side, i.e. into the inner volume of the housing part 8, this oil connection preferably running within the housing walls. This has the advantage that the leakage does not have to be transported back to the storage tank, but reaches the suction inlet directly. If the in-line piston pump 1 has several openings prepared as a suction connection in order to provide better or general accessibility for the in-line piston pump 1 in cramped installation conditions, there may be correspondingly several such oil connections running through the housing walls, which serve as leakage lines if necessary. In the same way as the openings that are not used as suction connections are closed, the corresponding oil connections that are not used as leakage lines must be sealed. In order to prevent the drive shaft chamber from being sucked dry with the corresponding consequential damage, the oil connection used as a leakage line can be equipped with a pressure relief valve. In order to discharge the leakage from the housing part 13, there are preferably several oil connections which are arranged in such a way that leakage discharge is ensured regardless of the mounting angle of the in-line piston engine. Explanation: In the case of the preferred mounting bracket, the basic housing 6 is located below the cover 8. Due to the structural space conditions, however, it may also be necessary for the cover 8 to be located below the basic housing. Claims 1. In-line piston pump (1) comprising: a drive shaft (2) for driving the pump (1), at least two pistons (3) which are operatively connected to the drive shaft (2) and which are arranged along a drive shaft axis (4) and are each arranged to be movable to and fro in a piston chamber (5), a base housing part (6) for receiving the drive shaft (2) and for inserting the at least two pistons (3) into corresponding receiving recesses (7), and a cover housing part (8) for attachment to the basic housing part (6), characterized in that the contact area (9) generated when the cover housing part (8) is attached to the base housing part (6) runs in a surface, preferably in a plane, which exposes the piston chamber (5) of a respective one of the at least two pistons (3). 2. Pump (1) according to claim 1, wherein the contact area (9) is designed so that when the base housing part (6) and cover housing part (8) are separated from one another, the piston (3) and at least one pressure valve (10) are inserted, preferably in In the form of high-pressure check valves in the basic housing part (6) and at least one suction valve (11) can be inserted into the cover housing part (8). 3. Pump (1) according to one of the preceding claims, wherein the drive shaft (2) is designed as a camshaft with single or multiple cams, as a crankshaft or eccentric shaft. 4. Pump (1) according to one of the preceding claims, wherein the drive shaft axis (4) runs parallel to a plane formed by the contact area (9). 5. Pump (1) according to one of the preceding claims, further comprising at least one suction valve (11) which is arranged in the cover housing part (8) and preferably does not protrude beyond the contact area (9) in an installed state. 6. Pump (1) according to claim 5, wherein the suction valve (11) and the piston (3) of a respective displacement unit have an identical longitudinal axis. 7. Pump (1) according to one of the preceding claims 5 or 6, wherein the respective longitudinal direction of the bores for receiving the at least one suction valve (11) runs perpendicular to a plane formed by the contact area (9). 8. Pump (1) according to one of the preceding claims 5-7, wherein the cover housing part (8) comprises a plurality of suction valves (11) arranged in parallel next to one another. 9. Pump (1) according to one of the preceding claims, further comprising at least one high-pressure check valve (10) which is arranged in the base housing part (6) and preferably does not protrude beyond the contact area (9) in an installed state. 10. Pump (1) according to claim 9, wherein the longitudinal axis of the piston (3) and the longitudinal axis of a high-pressure check valve (10) of a respective displacement unit are located on a plane which is preferably pierced perpendicularly by the drive shaft axis (4). 11. Pump (1) according to one of the preceding claims 9 or 10, wherein the base housing part (6) comprises a plurality of high-pressure check valves (10) arranged in parallel next to one another. 12. Pump (1) according to one of the preceding claims, wherein the respective longitudinal directions of the piston chambers (5) for receiving the piston (3) run perpendicular to a plane formed by the contact area (9) and preferably extend radially from the drive shaft axis (4) . 13. Pump (1) according to one of the preceding claims, wherein the piston (3) has a pin (31) which, in the installed state, exceeds the plane formed by the contact area (9) and preferably into the recess (14) which the The suction valve (11) of the same displacement unit accommodates, protrudes and preferably projects into the spring chamber of the compression spring (16) of the suction valve (11) which acts on a centering unit (15). 14. Pump (1) according to one of the preceding claims, further comprising a device (12) which is used to regulate or control the pump (1), which is preferably arranged in the cover housing part (8). 15. Pump (1) according to claim 14, wherein this device (12) for regulating or controlling the pump (1) is a suction throttle valve (121) which is preferably arranged so that its longitudinal axis is parallel to the drive shaft axis (4 ) is arranged. 16. Pump (1) according to one of the preceding claims, wherein the pump (1) comprises three separable housing parts (6, 8, 13), preferably only three separable housing parts (6, 8, 13), namely the basic housing part ( 6), the cover housing part (8) and a mounting flange part (13). 17. Pump (1) according to claim 16, wherein the basic housing part (6) comprises at least one outlet (20) that can be used for a high pressure connection, the high pressure check valves (10), the drive shaft (2), at least one drive shaft bearing and the recesses (7), the wall surfaces of which are the respective guides of the pistons (3) or their wall surfaces accommodate the cylinder liners of the pistons (3), the cover housing part (8) comprises at least one suction connection (18) and the suction valves (11), and the mounting flange part (13) is used to lead the drive shaft (2) out of an interior of the pump (1). 18. Pump (1) according to claim 16 or 17, wherein the drive shaft (2) is mounted on the mounting flange part (13), which can be introduced sealingly into a housing opening of the base housing part (6), so that the drive shaft (2) from this side can be mounted through the housing opening of the basic housing part (6) provided for the mounting flange part (13). 19. Pump (1) according to one of the preceding claims 16-18, wherein the base housing part (6) has at least two perforated fastening tabs which are aligned with a pair of several pairs of corresponding fastening holes in the mounting flange part (13) so that several around the Drive shaft (2) rotated mounting options of the base housing part (6) on the mounting flange part (13) exist. 20. Pump (1) according to one of the preceding claims 16, 18 and / or 19, wherein the basic housing part (6) in addition to the opening which can be reduced by the mounting flange part (13), to the drive shaft (2) from an interior of the pump (1) has a further opening for leading out the drive shaft (2), and the mounting flange part (13) is a cover part which can be fastened to the base housing part (6) in order to cover a drive shaft section led out from an interior of the pump (1), preferably the base housing part (6) and the cover part are designed with a dismantled cover part to enable the installation or removal of the drive shaft (2) through the area of the base housing part (6) covered by the cover part. 21. Pump (1) according to one of the preceding claims, wherein the base housing part (6) is designed such that the drive shaft (2) protrudes on two sides of the base housing part (6), so that a tandem operation of the pump (1) without making of changes to the basic housing part (6) is possible. 22. Pump (1) according to one of the preceding claims, wherein the fluid is fed to the suction valves (11) via a common suction channel running parallel to the drive shaft axis (4). 23. Pump (1) according to one of the preceding claims, wherein a suction connection (18) is arranged such that it is an extension of the common suction channel or is arranged in a bore which meets this suction channel at a right angle. 24. Pump (1) according to one of the preceding claims, wherein the high-pressure, pumped fluid is guided from the high-pressure check valves (10) to the high-pressure connection via a common high-pressure channel running parallel to the drive shaft axis (4). 25. Pump (1) according to one of the preceding claims, wherein in each displacement unit the central axis (71) of the recess (7) for the piston (3) and that of the recess for the high-pressure check valve (10) in an angular range between 15 ° and 60 ° to each other, preferably in an angular range between 25 ° and 45 °. 26. Pump (1) according to one of the preceding claims, wherein sealing elements (19) are inserted into recesses in the base housing part (6) and / or recesses in the cover housing part (8).