WO2013004620A1

WO2013004620A1 - Reciprocating piston pump with magnetic drive

Info

Publication number: WO2013004620A1
Application number: PCT/EP2012/062712
Authority: WO
Inventors: Pierre Mayoraz; Gaëtan DAYER; Ludovic Dovat
Original assignee: Wik Far East Ltd.
Priority date: 2011-07-01
Filing date: 2012-06-29
Publication date: 2013-01-10
Also published as: CN103649535A; EP2726738A1

Abstract

A reciprocating piston pump with a magnetic drive comprises a cylinder (2) which encloses a pump chamber (3) and has an outlet bore (4), an electric solenoid for the periodic generation of a magnetic field, an armature (24, 24.1) which can be moved by the magnetic field of the cylinder coil in the longitudinally axial direction of the pump chamber (3) with a piston (25, 25.1) which dips into the pump chamber (3) and can be moved back and forth therein by the movement of the armature (24, 24.1). The piston/armature component (23, 23.1) has an axial inlet channel 9, which armature (24, 24.1) is situated in an armature housing 13 which encloses an armature chamber. A pressure equalization path is provided between the piston side and the inlet side of the armature. The pressure equalization path has at least one channel (30) which opens into the piston-side section of the armature chamber and the longitudinal axis of which, which connects the piston side to the inlet side, extends parallel to the pivot axis of the piston/armature component 23, 23.1. The piston/armature component (23, 23.1) is a composite component, in which the armature (24, 24.1) is a tubular piece or is produced from a piece of this type, in the inner channel 28 of which the piston (25, 25.1) of smaller diameter engages by means of a connecting section (29, 29.1) and is thus connected to the armature (24, 24.1).

Description

Reciprocating pump with magnetic drive

The invention relates to a reciprocating pump with magnetic drive, comprising a barrel enclosing a pump cylinder with an output bore, an electric cylinder coil for periodically generating a magnetic field, a movable from the magnetic field of the solenoid in the longitudinal direction of the pump chamber armature with a dipping into the pump chamber and by the movement the armature piston reciprocating therein, wherein the piston-armature member having an axial inlet channel, which armature is located in an armature space enclosing anchor housing and a pressure compensation path between the piston side and the inlet side of the armature is provided.

Such electric fluid pumps, which are also referred to as solenoid pumps due to their electromagnetic drive or due to the movement of their piston-armature component as oscillating piston pump, are used when smaller amounts of liquid are to be promoted and / or when built by a pump a certain pressure shall be. Such liquid pumps are used in household appliances, such as coffee machines, irons or the like. When such a liquid pump is used in a coffee machine, it serves to convey water required for beverage preparation from a water tank to a continuous heating device and then to the brewing unit. If such liquid pumps are used in coffee machines which are suitable as a so-called fully automatic machine for brewing espresso, such pumps can provide the pressure required for an espresso preparation of about 10 bar or more with sufficient delivery rate. Another advantage of such liquid pumps is their small size.

Such a liquid pump is known, for example, from EP 1 818 538 B1 or EP 0 288 216 B1. Such a liquid pump is constructed from a cylinder enclosing a pump space, into which a piston moves in a longitudinal axial direction. The cylinder has an outlet bore that expels fluid delivered by the piston during pump operation. To the longitudinal axial Movement of the piston within the cylinder, this is connected to an armature, which in turn is longitudinally movable in an armature housing. The armature has ferromagnetic properties. The armature housing is surrounded by an electrical coil, through which a periodic magnetic field is generated. The armature is supported by means of a return spring formed as a compression spring at a bottom of the armature housing. The return spring acts on the armature and thus on the piston plunging into the cylinder in such a way that the liquid introduced into the pumping space pushes it out of the outlet bore due to the force of the spring. For supplying water to be pumped into the pump chamber, the magnetic field built up by the cylindrical coil serves to move the armature and thus the piston back against the force of the return spring, increasing the current volume of the pump chamber. The cylindrical coil is designed to generate a periodic magnetic field with alternating voltage and typically comprises a diode with which a magnetic field is generated only over the length of a half-wave of a period. By the return spring at each magnetic field interruption of the piston for pushing out of the same by the withdrawal movement of the pump chamber introduced water through the output bore of the cylinder moves. Thus oscillates the piston-armature component in the frequency having the applied AC voltage.

In order to allow water to flow into the pump chamber, the piston-armature component has a central through-channel. This is acted upon by a water supply, which opens into the armature housing enclosed by the armature housing. The liquid pump has an inlet connection, on which, for example, a hose connected to a water tank is seated.

In order to carry out the above-described water promotion, such a liquid pump has an inlet valve and an outlet valve. Both valves are designed as one-way valves. The valve body of the inlet valve is in its closed position at a located on the projecting into the pump chamber of the cylinder end of the piston, annular valve seat. The valve body of the exhaust valve is in its closed position at one of the outlet bore associated with the cylinder, annular valve seat.

In order to allow a pressure equalization between the piston side of the armature and the piston-side armature space and the inlet, a transverse bore is introduced in an integrally formed on the armature annular cylinder section, through which a Wegsamkeit is provided by the piston-side armature space to the inlet channel. This annular cylinder section has a larger outer diameter than the piston and does not dip into the cylinder. It is necessary for the functionality of the pressure balance to be open in any position of the oscillating piston.

From DE 20 2005 006 584 U1 a piston for a solenoid pump is described, which is designed as a composite piston. In this piston, the armature is made with its cylindrical extension and the transverse bore of a first material - a ferromagnetic material - while the piston can be a metal tube of a general type with or without seam. In this composite piston of the piston is welded to the integrally formed on the armature cylinder section.

The liquid pumps of the aforementioned type are relatively small. Nevertheless, there is a desire to further simplify this, in particular to make more cost-effective and to reduce the size required, if possible.

Based on this discussed prior art, the present invention seeks to further develop an aforementioned liquid pump in such a way that it can be designed as simple as possible building and thus inexpensive and with a smaller longitudinal axial extent.

This object is achieved according to the invention by a generic liquid pump mentioned above, in which the pressure equalization has at least one opening in the piston side portion of the armature space channel, the piston side with the inlet side connecting longitudinal axis parallel to the swing axis of the piston-armature component and in the the piston-armature component is a composite component is, in which the anchor is a piece of pipe or is made of such, in the inner channel of the smaller diameter piston engages with a connecting portion and is connected to the armature.

The piston-armature component of this fluid pump has longitudinal axial travel to provide pressure balance capability between the piston side of the armature and the inlet side. In this case, the inlet side may be the inlet channel section of the inlet channel assigned to the anchor. It is also possible that the pressure equalization in the form of one or more, the armature cross-channels is executed parallel to the longitudinal axis of the armature and thus opens at the inlet-side end side in the this side armature space section.

In the claimed concept no transverse bore is needed. Therefore, placing them on a ring cylinder portion as required in the prior art can be eliminated. Consequently, such a piston-armature component can be made shorter in terms of its longitudinal extent, whereby the total longitudinal extension of the liquid pump can be reduced.

An advantage of this concept is not only the possible shorter design of the liquid pump but also that the pressure compensation path has a longitudinal extension which is parallel to the direction of movement of the piston-armature component. As a result, an overflow of liquid from one armature side to the other armature side takes place optimized for flow, namely with the reduction of turbulence, which in turn results in a reduction of the overflow of the fluid from one armature space side to the other energy required. For the operation of such a liquid pump therefore less energy is consumed at the same capacity as in a conventional liquid pump of the type mentioned. Thus, the restoring compression spring needs to be equipped only with a correspondingly lower restoring force, which is why then the cylindrical coil unit can be made smaller.

According to one embodiment, it is provided that the inlet channel within the anchor has a diameter which is greater than the Au ßendurchmesser the piston and that the pressure balance is designed as one or more, the piston-side end face of the armature through cross-bore. It is provided that the at least one executed parallel to the longitudinal axis of the piston-armature component bore is arranged in a radial arrangement with respect to the outside of the piston that it opens into the inlet channel section of the armature. In the case of several holes, these are typically arranged at the same angular distance from each other, enclosing the piston.

According to a further embodiment, the pressure balance, for example in the form of multiple channels, passes through the armature in the longitudinal axial direction. Preferably, the channels are arranged at a distance from the outer lateral surface of the armature. It has been shown that then no loss of control of the armature by the magnetic field of the electric solenoid must be accepted.

The above-described concept of provided with respect to their longitudinal axis parallel to the swing axis of the piston-armature component pressure compensation capability allows the formation of piston-armature components, which are designed as composite components in particular extent. This allows to form the armature through a pipe section, which makes at least as far as possible unnecessary machining of conventional piston-armature components. It also goes along with this concept that ultimately no or only little material waste arises. Preferably, one will provide the inner wall of the inlet channel section of the armature cylindrical, so that these need not be processed an additional processing step to produce certain geometries, since cylinder tubes typically have such a Innenwandungsgeometrie in their manufacture. The piston as another piece of pipe, typically made of another, especially cheaper material engages with a portion - a connecting portion - in the inner channel of the armature and is fixed therein, for which purpose preferably a clamping member is used. Such a clamping member may be formed as a slotted polygonal tubular body, in the inner channel of the connecting portion of the piston is received and in turn is pressed into the inner channel of the armature and held therein by frictional engagement. It is the polygonal Forming the tubular tubular body not only to concentrate the clamping forces between the clamping member and the inner wall of the armature on the edges, but due to the geometry differences between the clamping member and the inner channel of the armature not filled by the clamping member cross-sectional areas of the round cross-section anchor channel at the same time the desired pressure equalization - opportunities. Likewise, pressure equalization paths are formed between the clamping member and the connecting portion of the piston.

Further advantages and embodiments of the invention will become apparent from the following description of embodiments with reference to the accompanying figures. Show it:

1 shows a longitudinal section through a piston pump with

Magnetic drive formed liquid pump with a piston-armature component according to the prior art,

2 shows a longitudinal section through a piston-armature component according to the invention,

Fig. 2a: an end view of the piston-armature component of the figure

2,

3 is a longitudinal section through a piston-armature component in principle corresponding to that of Figure 2 in an alternative embodiment,

3a shows a perspective view of the piston-armature component of

FIG. 3,

4 is a perspective view in the manner of an exploded view of the components of the reciprocating pump of Figure 1

5 is an enlarged perspective view of the upstream side

End of the cylinder and armature housing formed component and 6 shows a perspective cross-sectional view of the pump housing of the liquid pump of FIGS. 1 and 2 as an insight into the inlet-side bottom of the pump housing.

A designed as a reciprocating pump with magnetic drive fluid pump 1, also address as a solenoid pump, has a cylinder 2, which encloses a pump chamber 3. The pumping space 3 is limited on the output side by an outlet bore 4, which is introduced into the bottom 5 of the cylinder 2. At the bottom 5 of the pump chamber 3 pioneering a connector socket 6 is formed, in which the output hole 4 opens. This has an internal thread for connecting a pressure line. From the inlet side engages in the pump chamber 3, a piston 7 a. This is formed in the illustrated embodiment to an armature 8. The consisting of piston 7 and armature 8 component is made of a ferromagnetic material in stainless steel quality. This component passes through an inlet channel 9, with a first inlet channel section 10 being assigned to the anchor 8 and the adjoining inlet channel section 10. 1 to the piston 7. In the illustrated embodiment, the inner diameter of the channel portion 10 is greater than the outer diameter of the Zulaufkanalabschnitts 10.1 of the piston 7. In the piston 7 and anchor 8 existing component in the piston-side end face 1 1 of the armature 8 are distributed circumferentially and arranged at equal angular distance from each other Introduced pressure equalization holes through which the piston side of the armature 8 with its upstream side - is connected to the inlet channel section 10.1. Due to the sectional view, only two of the three pressure compensation openings 12, 12.1 can be seen in FIG.

The piston-armature component shown in Figure 1 is not part of the invention and serves the principal description of the functionality thereof to produce a Druckausgangswegsamkeit between the piston side of the armature 8 and its inlet side. The inlet side of the armature 8 is in this embodiment, the inlet channel section 10.1. The longitudinal axes of the pressure compensation openings 12, 12.1 extend parallel to the axis of vibration of the component. The openings 12, 12. 1 are arranged radially directly adjacent to the outer jacket surface of the piston 7. The diameter of the inlet channel section 10. 1 is larger than the outside diameter. Diameter of the piston 7. Therefore, open the pressure equalization holes 12, 12.1 in parallel alignment in the inlet channel section 10.1.

The outer circumferential surface of the piston 7 is sealed to form a labyrinth seal against the inside of the cylinder 2. This is realized by a very narrow gap between these two longitudinally axially movable components. Thus, no additional seal is necessary between the outer wall of the piston 7 and the inner wall of the cylinder 2. This also means that the piston 7 runs easily during its oscillatory movement within the pump chamber 3. The piston-armature component is guided in relation to its oscillating movement by the piston section engaging in the cylinder 2. Due to the above-described seal tumbling movements of the piston-armature component are avoided.

The armature 8 is located in an armature housing 13, which is formed in the illustrated embodiment of the cylinder 2. In the enclosed space of the armature housing 3 - the armature space - is on the inlet side, a compression spring 14 as a return spring, which is supported at one end to the armature 8 and at its other end to a bottom projection 15 of a pump housing 16. The bottom projection 15 merges into a connecting piece 17 on the inlet side, onto which a supply hose (not shown) comes to rest. The inlet hose is connected to a water supply. Due to the above-described leadership between piston-armature component and the cylinder 2, which is avoided or at least as good as avoided, the necessary movement gap between the outer surface of the armature 8 and the inside of the armature housing 13 can be very narrow dimensioned by a wobbling motion ,

In the piston-side part of the armature space, a damping spring 18 is housed. This is held between an externally formed on the cylinder 2 flange 19 and the end face 1 1.

On the armature housing 13, an electric cylinder coil unit is pushed. The cylindrical coil unit is designed and designed so that a periodic magnetic field can be generated by this. Becomes a Magnetic field generated, is moved by this the armature 8 against the force of the compression spring 14 and thus the piston 7 pulled out by increasing the volume of the pump chamber from the cylinder 2. If the magnetic field is interrupted, the energy stored in the compression spring 14 presses the armature 8 and thus the piston 7 back into their position shown in FIG. To generate the periodic magnetic field of the coil unit is associated with a diode and connected so that the magnetic field is generated only at one of the two AC voltage polarities. In this way, the piston-armature component oscillates in the longitudinal axial direction with respect to the longitudinal axis of the cylinder 2 and the armature space in the frequency of the AC voltage.

In order that liquid is conveyed as a result of the oscillating movement of the piston 7, namely from the inlet side of the pump 1 to the outlet side, the piston 7 is equipped at its end projecting into the pumping space 3 with a spring-less one-way valve as the inlet valve 21. This opens when the piston 7 is moved in the direction of the inlet side. When the direction of movement is reversed in the direction of the bottom 5 of the cylinder 2, the valve 21 closes. In the output bore 4, a second spring-less one-way valve is used as the outlet valve 22. Both valves 21, 22 are identical in the illustrated embodiment. Such a valve without valve spring has a guide portion connected to its valve body, which is typically made in one piece with the valve body. The guide section passes through the annular valve seat and protrudes in the case of the inlet valve into the inlet channel of the piston. In the case of the outlet valve, the guide section protrudes into the outlet bore of the cylinder enclosing the pump space. The guide portion is in the inlet channel or the output hole respectively starting from the closed position of the valve in the axial direction to open the same movable and captive to the respective component - the piston or the cylinder - connected. The longitudinal axial movability of the respective valve is dimensioned such that the opening cross-section is sufficient for passing the desired amount of water when lifted from the valve seat valve body. In the closed position of the respective valve body by taking advantage of the system pressure differences existing due to the movement of the piston between the inlet side of the valve body and its outlet side. In the case of the inlet valve, on the inlet side, this is at a typical application of such a liquid pump in a household appliance, so for example in a coffee machine, ambient pressure, in any case a pressure which is less than the delivery pressure. The inlet valve closes when the piston, by the force of the compression spring, makes its return stroke toward the output bore of the cylinder. In this movement prevails in the pump chamber and thus the output side to the valve body of the inlet valve, a higher pressure than the input side, with the result that the valve is automatically closed by the movement of the piston and the associated water flow. In the case of the output valve, this is opened by the liquid pressed through the outlet bore and closes automatically with the reversal of the pumping motion of the piston. Due to the enlargement of the pump chamber volume associated with this movement, a higher fluid pressure acts on the output side on the valve body of the outlet valve than on the input side.

Such a conception, in which at least one of the two valves is connected to the valve seat-providing component - piston and / or cylinder - and thus allows proper functioning even without the use of valve springs, reduces the number of components required to form the valves considerably. Finally, in addition to the valve seat forming component basically only one other component, namely the valve is needed. In addition, there is no risk in this design that the functionality of the liquid pump can be affected by breakage of a valve spring.

For connecting the inlet valve and / or the outlet valve to the respective component - piston or cylinder - these have according to a preferred embodiment of a guide portion which is segmented in the circumferential direction. The individual guide segment segments are spaced from each other, leaving flow gaps. At least one of these guide segment segments carries a radially outwardly projecting Verklammerungsnase whose facing in the direction of the valve body surface constitutes a stop surface. This abutment surface cooperates with a component-side abutment surface to limit the opening movement amount of the valve. The component side abutment surface may be formed for example by a circumferential groove, as is preferred in the case of the inlet valve. This groove is introduced into the inner circumferential surface of the inlet channel of the piston. In the case of the outlet valve, it is possible for the at least one clamping nose to engage behind the outlet bore and thus engage in the pump chamber.

A valve as prescribed can be inexpensively made of plastic, for example by means of a plastic injection molding process. If a use of plastic is not desired, it is advisable to produce the valve made of metal, for example a suitable brass alloy. The valves 21, 22 can also be used independently of the concrete piston pump described concretely in the embodiment of FIG. 1 and also independently of the embodiment of the piston-armature component concretely described in the context of these embodiments.

Figure 2 shows a piston-armature component 23 according to the invention, which is designed as a composite component. This piston-armature component 23 is part of a reciprocating pump with magnetic drive, as described for Figure 1. In the piston-armature component 23, the armature 24 is a piece of pipe made of a ferromagnetic material in stainless steel quality. The armature 24 is cylindrical, as can be seen from the view of the component 23 in Figure 2a. Thus, the anchor 24 can be made as a pipe section. The piston 25 is also a metal pipe section. The piston 25 is shown without the one-valve inlet valve associated therewith. Visible within the piston 25 in its immersed into the cylinder end portion in the inner wall introduced groove 26 in which the inlet valve is held clamped. The piston 25 is connected with the interposition of a clamping member 27 with the armature 24, wherein the clamping member 27 and the piston 25 are inserted into the inner channel 28 of the armature and clamped therein. The clamping member 27 in the illustrated embodiment is a slotted square tube piece (see FIG. 2a). Thus, the cross-sectional geometry of the clamping member 27 differs from the circular cross-sectional geometry of the piston 25 and the inner channel 28 of the armature 24. The clamping member 27 is for applying the desired clamping force slits. The piston 25 is frictionally held in the clamping member with a connecting portion 29. The polygonal design of the clamping member 27, wherein in the illustrated embodiment, a quadrangular (square) cross-sectional shape has been selected, serves the purpose that not the entire inner channel cross-sectional area is filled by the clamping member 27. In this way, four overflow 30 remain between the inner wall of the armature 24 and the outer side of the clamping member 27. Since the clamping member 27 of the illustrated embodiment extends through the anchor 24 in total, also the overflow 30 extend through the armature 24 therethrough. It is understood that for holding the piston 25, the clamping member 27 could have been designed shorter. In the illustrated embodiment, the clamping member 27 protrudes on both end sides of the armature 24 on this. These protruding portions serve to hold a return spring on the one hand and a damping spring on the other hand.

Similarly, also between the outside of the piston 25 and the inside of the clamping member 27 and within the slot pathways that serve the same purpose as the overflow 30th

During the oscillatory movement of the piston-armature component 23 during operation of the liquid pump in which this component 23 is installed, liquid can flow unhindered from the one armature side via the above-described throughflow paths, in particular provided by the overflow channels 30 from one side of the armature space to the other stream. The orientation of these pathways to the longitudinal axis of the axis of movement of the piston-armature component 23 allows pressure equalization by overflow of liquid exclusively in the axis of movement. The same also applies to the piston-armature component of the liquid pump of Figure 1. This explains why less energy has to be expended for forcing fluid through this overflow pathway with comparatively equal cross-sectional area.

FIG. 3 shows a piston-armature component 23. 1, which is constructed in principle like the piston-armature component 23. The piston-armature component 23. differs from the component 23 only in that the clamping member 27.1 on the piston side protrudes further from the armature 24.1. The connecting portion 29.1 of the piston 25.1 ultimately does not penetrate into the interior of the armature 24.1. The front view of the piston-armature component 23. 1 corresponds to that shown in FIG. FIG. 3a shows the piston-armature component 23.1 in a perspective view.

FIG. 4 shows the individual building components of the liquid pump 1. It can be seen that the cylinder 2 and the armature housing 13 form a one-piece component. This component is identified by the reference numeral 23 in the figures. The component 23 carries in the region of its inflow-side end portion a flange 31, which forms a contact flange for the assembly, generally designated by the reference numeral 32, which comprises the electrical components of the liquid pump 1.

The enlarged perspective view of Figure 5 on the inflow-side end portion of the piston-armature component 23 makes the flange 31 clearly visible. Spaced apart from the flange 31 in the direction of the inlet-side end of the component 23, two bayonet cams 33, 33.1 projecting outward in the radial direction are provided as connecting members with which the component 23 can be detachably connected to the bottom 34 of the pump housing 16. From the bayonet cams 33, 33.1 spaced from the inlet-side mouth of the component 23 is a circumferential groove 35 into which a sealing ring 36 is used to seal against the pump housing 16.

As can already be seen from FIG. 1, the base 34 of the pump housing 16 has an annular connecting recess 37, into which the connection-side connection section of the component 23 is inserted for connecting the component 23 to the pump housing 16. FIG. 6 shows the connection recess 37, also with the cam bolts 31 complementary to the bayonet cams 33, 33. Thus, the component 23 by inserting its connecting portion into the connecting recess 30 and corresponding rotation of the two components against each other this releasably sealed together connectable. The sealing ring 36 acts against the inner wall of the connected components 16, 23. Bonding recess 37 (see Figure 1).

The provision of the pump housing 16 also allows the use of an electric solenoid, around which is not surrounded for insulation a plastic sheath. Therefore, in the pump housing 16 basically all necessary for the operation of the liquid pump 1 electrical / electronic components can be accommodated. This also includes the fuse typically associated with such a fluid pump. Especially when such a fuse is designed as a thermal fuse, it can be arranged in the immediate vicinity of the coil and without an intermediate plastic layer. The modularity thus allows that when using a thermal fuse and after blowing through the same not the entire liquid pump, but only the assembly 25 or even only the fuse must be replaced.

On the outside of the pump housing, in particular on its end face carrying the connecting piece 17, connecting members can be arranged. These can be used to connect one or more further units to the liquid pump 1. This may in particular be a flow measuring device in order to monitor the amount of liquid delivered by the liquid pump 1. The links may be designed as a locking hook as part of a bayonet lock.

The above description of the construction of the piston-armature component 23 and its connection to the pump housing 16 can also be used independently of the object specifically claimed.

LIST OF REFERENCE NUMBERS

1 fluid pump 34 bottom

2 cylinder 35 groove

3 pump room 36 sealing ring

4 outlet hole 37 recess

5 bottom 38 cam latches

6 connection socket

7 pistons

8 anchors

9 inlet channel

, 10.1 inlet channel section

face

, 12.1 Pressure equalization opening

13 anchor housing

14 compression spring

15 ground projection

16 pump housings

17 connecting pieces

18 damping spring

19 flange

20 cylinder coil unit

, 21 .1 inlet valve

22 exhaust valve

, 23.1 Piston Anchor Component

, 24.1 anchor

, 25.1 Pistons

26 groove

, 27.1 Clamping element

28 inner channel

, 29.1 Connecting section

30 overflow channel

31 flange

32 assembly

, 33.1 bayonet cam

Claims

claims

A reciprocating piston pump with magnetic drive, comprising a cylinder (2) enclosing a pumping space (3) with an output bore (4), an electric cylindrical coil for periodically generating a magnetic field, an armature (8) movable from the magnetic field of the cylindrical coil in the longitudinal axial direction of the pumping space (3) , 24, 24.1) with a piston (7, 25, 25.1) immersed in the pump chamber (3) and reciprocable therein by the movement of the armature (8, 24, 24.1), the piston-armature component (23 , 23.1) has an axial inlet channel (9), which armature (8, 24, 24.1) is located in an armature space enclosing armature housing (13) and a pressure compensation path between the piston side and the inlet side of the armature is provided, characterized in that the Druckausgleichswegsamkeit at least one opening in the piston-side portion of the armature space channel (12, 12.1; 30), the piston side connecting to the inlet side longitudinal axis parallel z ur swing axis of the piston-armature component (23, 23.1) extends, and that the piston-armature component (23, 23.1) is a composite component, wherein the armature (24, 24.1) is a piece of pipe or made of such a piece , in the inner channel (28) of the smaller diameter piston (25, 25.1) with a connecting portion (29, 29.1) engages and with the armature (24, 24.1) is connected.

Reciprocating pump according to claim 1, characterized in that the inner wall of the inlet channel section (10.1) of the armature (8, 24, 24.1) is cylindrical.

Reciprocating pump according to claim 1 or 2, characterized in that the inlet channel (9 or 10.1) within the armature (8) has a diameter which is greater than the outer diameter of the piston (7).

Piston pump according to claim 4, characterized in that the channel as a piston-side end face of the armature (8) thorough bore (12, 12.1) is executed.

Reciprocating pump according to claim 4, characterized in that circumferentially distributed and arranged at the same angular distance from each other a plurality of such holes (12, 12.1) are provided which form the pressure compensation in their entirety.

Piston pump according to one of claims 1 to 3, characterized in that the at least one channel (30) passes through the armature (24, 24.1).

Reciprocating pump according to claim 6, characterized in that circumferentially distributed and arranged at the same angular distance from one another a plurality of such channels (30) are provided.

Reciprocating pump according to one of claims 1 to 7, characterized in that the cross-sectional area of the armature enclosed by the portion of the inlet channel is greater than the cross-sectional area of the piston and deviating from the circular cross-sectional geometry of the piston cross-sectional geometry, in particular has a polygonal cross-sectional geometry.

Reciprocating pump according to one of claims 1 to 8, characterized in that the piston (25, 25.1) with a connecting portion (29, 29.1) with the interposition of the connecting portion (29, 29.1) of the piston (25, 25.1) enclosing, as a slotted polygonal Tubular body formed clamping member (27, 27.1) is fixed and due to the differences in cross-sectional geometry between the clamping member (27, 27.1) and the armature (24, 24.1) and / or between the clamping member (27, 27.1) and the piston (25 , 25.1) existing intermediate spaces form the pressure compensation.

Reciprocating pump according to claim 9, characterized in that the clamping member (27, 27.1) has a square inner and outer geometry.