EP0816675B1 - Arrangement for stabilizing the eccentric ring of a radial piston pump - Google Patents

Description

The invention relates to a device for stabilization the eccentric ring of a radial piston pump with several pistons driven by a common eccentric shaft, according to the preamble of claim 1.

Such radial piston pumps are often used for feeding the common high-pressure line (common rail) of a fuel injection system used for vehicles because of such Pumps with a relatively small construction volume high Provide pressures and a good response of the Have regulation. Depending on the pressure in the common rail on the operating parameters of the fuel supply system according to the current pressure fluid requirement to regulate the radial piston pump for example an adjustable suction throttle upstream, which thus as a fluid flow limiting device functions, so that the individual pistons of the radial piston pump only so much Pressurized fluid, i.e. Convey fuel as in the common rail is actually needed. It can thus differ in the individual Pump chambers extreme under certain conditions Stop undersupply, even then, when the pistons are pressurized fluid, i.e. Low pressure fuel suction, which is already using a pre-feed pump is under pressure. Hold radial piston pumps such operating conditions, in which in particular on Inlet of the pump chamber cavitation can occur proportionately stood well. Because the piston against the support surface The spring that prestresses the eccentric ring can usually be dimensioned large enough to ensure that the piston or the one that is in a power chain Sliding shoe constantly follows the support surface of the eccentric ring.

As long as the pump chamber is in the suction stroke of the pump piston is completely filled with pressurized fluid Plurality of one another at a uniform circumferential distance standing radial piston at least one sliding shoe is sufficient high radial force on the associated support surface of the eccentric ring around this through the surface contact between slide shoe and support surface in the circumferential direction stabilize. So that the eccentric ring is twisted too can then be prevented if the pressure fluid supply to Pump chamber of the high pressure pump fails in the DE 35 22 479 A1 in a generic radial piston pump an additional one that is supported on the pump housing Stabilizing part provided, which is flat against another Prestressed stabilizing surface of the eccentric ring is. This stabilizing part is spring loaded Piston formed, which is biased radially inwards and with its radially inner front end flat against an associated flattening of the eccentric ring suppressed. Thus, the eccentric ring is also when the Piston in the event of pressure fluid supply failure are no longer pressed against the support surfaces, against Twisted secured. After restarting the pump after a The pump can therefore fail without supply medium previous, realignment of the eccentric ring again be started so that pump downtimes are avoided.

According to a special embodiment according to FIG. 3 the stabilizing piston radially inside the pump piston led and is supported with its front plate section on the ring collar of the pump piston. The inner of the stabilizing piston is via a radial channel, a Axial channel and a throttle element can be filled with pressure fluid, creating a damping effect for the radially after internally moving pump piston can be achieved.

Radial piston pumps with one described above Build-up is not only for ever higher system pressures, but also used for ever higher speeds. Since the eccentric ring in such radial piston pumps moved on a circular path, being parallel to self-shifting takes place between the pump piston or an associated slide shoe and the flattened Support surface of the eccentric ring a relative sliding movement instead of. The frictional force tends to close the eccentric ring twist. Because the frictional force changes cyclically with the angle of rotation the eccentric shaft changed, it is ultimately special responsible at higher speeds that no longer controllable torsional / tilting vibrations of the eccentric ring occur, the functionality of the radial piston pump impair and lead to increased wear of the individual components of the radial piston pump being able to lead. These undesirable torsional / tilting vibrations occur particularly when the radial piston pump is equipped with a so-called suction throttle control or if in the pressure fluid supply of individual displacement pistons Throttle or valve members are provided with which at least individual displacers or pump pistons, so to speak be switched off.

The invention is therefore based on the object Device for stabilizing the eccentric ring of a radial piston pump according to the preamble of claim 1 to create with the in all operating conditions and in particular at high speeds and in suction throttle mode Pressure fluid undersupply of individual displacers torsional / tilting vibrations of the eccentric ring effectively excluded become.

This object is achieved through the features of the patent claim 1 solved.

According to the invention, the eccentric ring is arranged by a displacement element stabilized in every phase of movement the radial piston pump stabilizes the eccentric ring receives active pressurization. This is given the opportunity to stabilize the Adjust the operating state of the pump and for example in the operating phases critical for torsional / tilting vibrations, i.e. at high speeds and / or with an undersupply the pump chambers of individual or all pump pistons to keep the stabilizing force high enough to To protect the eccentric ring against torsional / tilting vibrations. The force required to stabilize the eccentric ring can be optimized energetically, for example, by only in a very specific speed range and / or depending on parameters of the suction throttle control or the pressure fluid supply of individual or all Pump pistons provided with special effectiveness becomes. In other operating states in which the eccentric ring such torsional / tilting vibrations in particular According to the invention, the stabilizing force is subject to circumference be kept lower, reducing efficiency the radial piston pump is adjustable to an optimum.

The displacement element arrangement itself can be of various types Embodiments are provided. A first variant is the subject of claims 2 to 5. This variant has the particular advantage that the stabilizing device independent of the other components of the radial piston pump can be designed, which is positive in terms of on retrofitting of conventional radial piston pumps with a stabilizing device according to the invention effect. With sufficiently large dimensions the pressure chamber of the displacement element and preferably at largely large design of the contact area between the cup-shaped pistons and the stabilizing surface on the eccentric ring, a single cup-shaped piston is sufficient, around the eccentric ring in the critical operating states Protect against torsional / tilting vibrations. For energetic Optimizing the radial piston pump can reduce the internal pressure the cup-shaped piston preferably after one certain control profile to be changeable, the one determined at the operating point Adjusted parameters of the radial piston pump is. It has been shown that such an embodiment the displacement element arrangement is particularly useful can be used if there are no more than three pump pistons are sufficient in this way at the eccentric ring large stabilization area between two neighboring ones Support surfaces are formed on the eccentric ring can.

When the number of cup-like pistons increases the stabilization effect can be improved further. If, for example, three are evenly spaced apart mutually stabilizing piston according to claim 5 are provided, is at least a cup-shaped piston in a radially outward direction Displacement phase, so that the possibility is given is the support force of this stabilizing piston in this Additional movement phase to raise. The degree of increase the stabilizing force in this movement phase of the Stabilizing piston can be particularly simple Way via the pressurized fluid supply opening for the inside of the cup-like piston.

Another variant of the stabilization device for the eccentric ring, which is particularly suitable for embodiments of radial piston pumps that are more than has three, for example five and more radial pistons, is the subject of claims 6 ff. This variant has the particular advantage that the stabilizing device into the individual cylinder insert modules of the radial pistons can be integrated, making it a very space-saving Order results. Because several, preferably in even Angular spacing between plate-shaped elements and associated movable support sleeves are provided, with which a corresponding number of pressure fluid chambers will be limited when the pump shaft moves always at least one pressure fluid chamber in the radial direction outward movement phase of the assigned pump piston briefly pressurized, causing the eccentric ring can be stabilized via the associated support surface, even if the pressurized fluid supply of all or individual pump chambers is throttled so much that the pump chamber can no longer be filled completely can. About the throttled displacement of the in the pressure fluid chamber trapped pressure fluid can build up the pressure and thus meter the stabilizing force well, and for example in such a way that in a specific Speed range of the stabilization effect particularly effective established. This speed range is set so that it coincides with the critical speed range in which the rotational / tilting vibrations of the eccentric ring described at the beginning occur primarily.

Because to limit the pressure fluid chamber plate-shaped Elements are used, the installation space is radial Direction by the measures according to the invention only slightly raised. The support sleeve can also be very space-saving into the individual units or modules in the area integrate the cylinder inserts. For the pressure fluid chamber According to the invention, no additional installation space is required taken. For this purpose, the cylinder space between the radial inside face of the cylinder insert and pulled a sliding shoe on which the pump piston supported. The support sleeve can do other tasks transmitted, e.g. the task of a support surface to provide for the return spring of the pump piston.

The support sleeve fulfills with the further development of the claim 7 the function of a valve for time-controlled Filling to stabilize the eccentric ring used pressure fluid chamber. For guiding the support sleeve there are various options. According to one the first variant according to claim 8 is the support sleeve guided on the outer surface of the cylinder insert while them according to the variant according to claim 16 via a bore coaxial to the piston in the pump housing is.

Additional space is provided by the training of Claim 10 saved by for the throttle channel arrangement the contact area between the support sleeve and plate-shaped element is used. A particularly simple one Design of the plate-shaped element results with the further development of claim 14. The plate-shaped According to this development, element can be a perforated disc be formed axially fixed via a radial collar is connected to the pump piston.

This configuration leaves. yourself in an advantageous manner according to claim 15 so axially brace that relative movements between support sleeve, plate-shaped element and Avoid sliding shoe, causing excessive wear is counteracted.

With conventional radial piston pumps it becomes regular a fluid feed system is used, through which the main stage is fed. For example, integrated Vane pumps used. With the further development of the claims 24 to 32 manage to supply the main level improve the reduction in the number of parts and the Optimizing the device energetically.

According to this training, the cyclical Movement of the displacement element arrangement for pre-conveying purposes used, with a particular additional advantage shows that the phase shift between the feed pump and high pressure pump is automatically eliminated.

The radial piston pump can be easily assembled being held. Due to a reduced number of components the manufacturing cost can be reduced.

Works in the radial piston pump according to claim 24 to 31 the stabilization device simultaneously as a pre-feed pump, with only minor design changes required are from the radial piston pump with stabilizing device to the radial piston pump with stabilizing device and pre-feed pump. Through these measures Both the assembly of the pump are simplified as well the manufacturing cost is reduced. Furthermore, with these Embodiments of the startup behavior at the starting speed improved since the pre-feed pump after the Piston displacement principle works. In addition, one better synchronization between pre-feed pump and high pressure pump possible because the pump frequencies are in phase. The drive end of the shaft can be more variable be trained because the bearing diameter is none Restrictions. Furthermore, the pump can be made shorter by the length of the vane pump.

With the features of claims 25 and 30, the Stabilizing device in the specific embodiment of the preceding claims by simply adding a slot control device and a check valve as well as a pressure channel and a suction channel on simple Way the integrated pre-conveyor function. Through the Slit control optimizes the pressure build-up phase.

According to claims 25 and 30, the support sleeve is on the outer surface of the cylinder insert or in a to Piston coaxial bore provided in the pump housing. Thereby stable pump operation is guaranteed.

The training according to claims 26 and 27 relate two variants for the slot control device. The slots can either be in the support sleeve or be provided in the sealing sleeve. With these slits a restricted flow of fluid is ensured. If the Support sleeve with its outer diameter in the housing the partial volume flows occurring can be directly in the Housing are brought together via check valves (Figure 9), which further simplifies the structure. Otherwise an additional element in the form of a sealing sleeve is used, around the volume flow from the annular displacement chamber to transfer into the housing.

With the variant according to claim 27 arises as special Advantage that the sealing length can be kept longer can.

To arrange the check valve to save space according to claim 28 a sheet metal tongue of a flat gasket Sheet used as a check valve. Another space-saving The arrangement of the check valve consists in the integration in a pressure screw of the support ring of a pressure chamber insert. The support ring is particularly advantageous because this can be positioned independently of the cylinder insert is. Static overdeterminations of the pump mechanics can thus effective in the area of the cylinder insert be avoided.

The developments of the device according to the claims 31 and 32 have the advantage that a spring for a sufficient Contact pressure of the piston on the eccentric ring provides. The configuration of the slot control device used there can be due to particularly minor constructive Changes to an existing pump design can be realized.

Advantageous further developments are the subject of the rest Dependent claims.

Fig. 1 einen schematisierten Schnitt einer Radialkolbenpumpe mit drei Radialkolben und einer ersten Ausführungsform der Vorrichtung zur Stabilisierung des Exzenterrings;

Fig. 2 eine der Figur 1 ähnliche Ansicht einer Radialkolbenpumpe gemäß einer Variante der Ausgestaltung nach Figur 1;

Fig. 3 eine schematisierte Schnittansicht (Längsschnitt) einer dritten Ausführungsform der Radialkolbenpumpe mit einer weiteren Variante der Vorrichtung zur Stabilisierung des Exzenterrings;

Fig. 4 in vergrößerter Darstellung eine Einzelheit der Ausgestaltung nach Fig. 3;

Fig. 5 in einer der Figur 1 ähnlichen Darstellung eine weitere Variante der Radialkolbenpumpe mit einer modifizierten Vorrichtung der Stabilisierungsvorrichtung für den Exzenterring;

Fig. 6 in einer der Figur 4 ähnlichen Darstellung eine weitere Variante der Radialkolbenpumpe mit einer modifizierten Version der Vorrichtung zur Stabilisierung des Exzenterrings;

Fig. 7 einen vergrößerten Teilschnitt - ähnlich der Darstellung gemäß Figur 6 - zur Erläuterung einer weiteren Variante der Vorrichtung zur Stabilisierung des Exzenterrings einer Radialkolbenpumpe;

Fig. 8 eine Schnittdarstellung einer Variante der Vorrichtung zur Stabilisierung des Exzenterrings einer Radialkolbenpumpe, mit der zusätzlich die Funktion einer Vorförderpumpe erfüllt wird;

Fig. 9 einen vergrößerten Teilschnitt zur Erläuterung einer weiteren Variante der Vorrichtung zur Stabilisierung des Exzenterrings einer Radialkolbenpumpe, bei der zusätzlich die Funktion einer Vorförderpumpe ausgeführt wird; und

die Fig. 10 und 11 Schnittdarstellungen von Abwandlungen von der in Fig. 8 dargestellten Vorrichtung.

Several exemplary embodiments of the invention are explained in more detail below with the aid of schematic drawings.
Show it:

Figure 1 is a schematic section of a radial piston pump with three radial pistons and a first embodiment of the device for stabilizing the eccentric ring.

2 shows a view similar to FIG. 1 of a radial piston pump according to a variant of the embodiment according to FIG. 1;

3 shows a schematic sectional view (longitudinal section) of a third embodiment of the radial piston pump with a further variant of the device for stabilizing the eccentric ring;

FIG. 4 shows an enlarged view of a detail of the embodiment according to FIG. 3;

5 shows a further variant of the radial piston pump with a modified device of the stabilizing device for the eccentric ring in a representation similar to FIG. 1;

6 shows, in a representation similar to FIG. 4, a further variant of the radial piston pump with a modified version of the device for stabilizing the eccentric ring;

7 shows an enlarged partial section - similar to the illustration according to FIG. 6 - to explain a further variant of the device for stabilizing the eccentric ring of a radial piston pump;

8 shows a sectional illustration of a variant of the device for stabilizing the eccentric ring of a radial piston pump, with which the function of a prefeed pump is additionally fulfilled;

9 shows an enlarged partial section to explain a further variant of the device for stabilizing the eccentric ring of a radial piston pump, in which the function of a prefeed pump is additionally carried out; and

10 and 11 are sectional views of modifications of the device shown in Fig. 8.

In Figure 1 with the reference number 10 is a pump housing referred to in the three at an even circumferential distance radial piston / cylinder arrangements facing each other are recorded which are connected to a central pump shaft, i.e. more specifically with an eccentric section 12 of the pump shaft interact. At 11 is the axis of the pump shaft designated, while at 13 the center of the eccentric section 12 is designated by the dimension E to the axis 11 is offset. On the eccentric section 12 is rotatable Eccentric ring 14 mounted on the outside of a corresponding to the number of piston / cylinder arrangements Number of flattened support surfaces has 16.

A sliding shoe is supported on the supporting surfaces 16 18 from the axially by means of a clamp element 20 firm and captive with the associated pump piston 22 connected is. The pump piston 22 also sits radially centered in the slide shoe 18, which is thus with its contact surface 23 remains aligned perpendicular to the piston axis 24.

The piston axis 24 extends essentially radially to the pump shaft, the orientation being predetermined by a cylinder insert 26 which is received in a corresponding recess 25 in the pump housing 10 and is fixed therein by means of a screw cap 28. With the inner bore of the associated cylinder insert, the pump piston 22 defines a pump chamber 30, which can be fed with pressure fluid via a suction valve 31 designed as a check valve, which is at a supply pressure P. On the other hand, a branch passage 32 extends from the pump chamber 30, which leads to a pressure valve 33, which is also designed as a check valve, which is accommodated in the pump housing 10 and is connected to a common high-pressure line 34 in which the high pressure P ₁ prevails. The common high-pressure line 34 forms, for example, the so-called "common rail" of a fuel injection system of an internal combustion engine.

A return spring is designated by reference number 35, which is designed as a compression spring and one hand on a head portion of the cylinder insert 26 and on the other supported on the bracket member 20 so that the associated Pump piston 22 when the eccentric section 12 is moving can perform his suction stroke.

FIG. 1 shows the upper piston in the top dead center position, i.e. in the state in which the pump chamber 30 the occupies minimal volume. When the eccentric section moves on 12 follows the pump piston 22 under the action the compression spring 35 of the movement of the eccentric ring 14, which is parallel to itself on a circular path with the radius E is shifted, whereby the pump chamber 22nd enlarged and pressure fluid sucked through an axial bore 36 becomes.

As long as the pressure fluid supply under the supply pressure P is sufficiently large to completely fill the pump chamber 30, the forces of the springs 35 and the pressure force of the pump piston 22 * which is in the compression phase are sufficient to the eccentric ring 14 in the position shown to stabilize. Radial piston pumps of the type shown are, however, frequently suction throttle-controlled, ie the pressure P ₁ is regulated by a variable suction throttle in such a way that the individual pistons displace only as much pressure fluid in the high-pressure range as is required to maintain the required pressure level. This means that in such operating conditions there is an undersupply of the pressure chambers 30 in question, so that the force of the compression spring 35 is no longer sufficient to move the pump piston 22 radially inward against the negative pressure building up in the pump chamber. In such an operating state, the pump chamber 30 * either does not build up the high pressure at all or with such a time delay that the radially inwardly directed piston force cannot be used effectively to stabilize the eccentric ring 14. These operating states are disadvantageous, in particular at high speeds, because they can lead to rotational / tilting vibrations of the eccentric ring 14.

In order to exclude such vibrations, the radial piston pump according to FIG. 1 has a device for stabilizing the eccentric ring in the form of a hydraulic displacement element arrangement, with which the eccentric ring 14 is stabilized in every movement phase of the pump by actively pressurizing the displacement element arrangement. In particular, a cup-shaped piston 40 is provided, which is supported with its bottom 42 on a flat stabilizing surface 44 of the eccentric ring 14. The cup-shaped piston 40 is slidably guided in a radial bore 46 of the pump housing 10 and defines in its interior and in cooperation with the radial bore 46 a pressure chamber 48 which is connected via at least one axial channel 47 in a screw plug 50 to a pressure fluid system under the pressure P2 , The inner diameter D40 and the pressure in the pressure chamber 48 determine the radial pressure force F _R with which the cup-shaped piston 40 is constantly pressed against the stabilizing surface 44 of the eccentric ring 14, as a result of which the latter is independent of the pressure conditions and of the fluid supply to the pump chambers 30, 30 * in the position shown is held.

The pressure level P2 can be kept at a constant value become. However, it is equally possible to use this Pressure P2 depending on the operating states of the radial piston pump to optimize so that the stabilizing effect then primarily provided for the eccentric ring 14 if, for example, in a particular Speed range or when switching off one or all Pump piston is a priority. By appropriate dimensioning of the at least one axial channel 47, the pressure in the Pressure chamber 48 can even be raised cyclically, in which the Throttle effect of the axial channel 47 is used.

In the embodiment according to FIG. 1, it is cup-shaped Piston 40 also radially by a compression spring 49 biased inside. The compression spring 49 is inside the cup-shaped piston 40 received and supports itself on the underside of the locking screw 50. The Compression spring 49 not only has a radial force that increases Effect, but it ensures a complete loss of pressure in the pressure system with pressure P2 for the eccentric ring 14 remains stabilized.

The embodiment according to FIG. 2 differs from that according to FIG. 1 only in that several such pistons 140-1 to 140-3 are provided instead of a single cup-shaped piston, which are in flat contact with separate stabilizing surfaces 144 on the eccentric ring 114. This variant ensures that at least one cup-shaped piston 140 is moved radially outwards in each phase of movement of the eccentric section 112, so that the associated reduction in the pressure space 148 in conjunction with the throttle function of the axial channel 147 can be used to increase the stabilizing force F _R. In the embodiment according to FIG. 2, the piston 140-3 is in this phase, so that an increased stabilizing pressure can build up in the pressure chamber 148-3, which can also be used to stabilize the eccentric ring 114.

In the exemplary embodiments described above became the device for stabilizing the eccentric ring provided by an additional facility. Hereinafter variants are described in which the device to stabilize the eccentric ring in the piston / cylinder arrangement the radial piston pump is integrated. To simplify the description, the following are for those components that the components of the previously described Embodiments correspond or are comparable are provided with similar reference numerals to which however, a "2" (Figures 3 and 4), a "3" (Figure 5), a "4" (Figure 6) or a "5" (Figure 7) is prefixed.

Figure 3 shows a radial piston pump with several - for example 3 to 5 cylinder inserts 226, which are stepped in Radial bores 225 with essentially radial Alignment is included in the pump housing 210. On the Eccentric section 212 is over a sliding coating 252 the eccentric ring 214 rotatably mounted on which the radial piston Support 222 using a slide shoe 218. In the area of the pump chamber 230, the suction valve and the Pressure valve there are no differences from the previous one described embodiment, so that a closer Description of these details can be omitted. Differently is the way the eccentric ring 214 in every phase of movement of the radial piston pump against torsional / tilting vibrations is stabilized. To explain the Stabilization device is referred to Figure 4, which only differ from the configuration according to FIG differs in that the pressure valve is not in Pump housing 210, but received in the cylinder insert 226 is.

Each pump piston 222 is in the region of its radially inner one End section axially fixed with a plate-shaped Element 254 connected so that it is together with the piston 222 and the slide shoe 218 moves. The plate-shaped Element 254 rests on an inner shoulder 256 of a support sleeve 258 to that with a first section with sliding fit on a cylindrical outer surface 259 of the cylinder insert 226 is guided axially movably and with a further section radially surrounds the slide shoe 218 and is supported on the support surface 216 of the eccentric ring 214. The section guided axially movably on the cylinder insert 226 the support sleeve 258 has at least one radial opening 260 on that shown in Figures 3 and 4 Position of the cylinder insert 226 is closed. The position of the piston shown in Figures 3 and 4 222 and thus the support sleeve 258 is the top dead center position, i.e. the position in which the pump chamber 230 the occupies smallest volume. In one around the phase angle of 180 ° shifted position of the eccentric section 212, in which is the maximum volume of the pump chamber 230 is Piston 222 and thus the support sleeve 258 radially as far behind shifted inside that the at least one radial breakthrough 260 the radially inner end face 262 of the cylinder insert 226 reached, so that a pressure fluid chamber 264th between the end face 262 of the cylinder insert 226 and the plate-shaped element 254 with pressure fluid from a Room 266 is fillable. The pressure fluid is in this room regularly under a very slight overpressure.

With the reference numeral 268 is at least one axial bore or an axial breakthrough in the plate-shaped element 254 and the reference numeral 270 denotes a radial channel, the back of the plate-shaped element 254 with connects a room 267 in which is essentially the same Pressure as in room 266 prevails. The channels 268 and 270 are thus part of a throttle arrangement, via which the in the pressure fluid chamber 264 displaces trapped pressure fluid can be, if the support sleeve 258 in the compression stroke of the Piston 222 against the force of the Rüchholfeder 235, which is supported radially on a shoulder 272 of the support sleeve 258 is moved outwards. The following results Functionality:

At the beginning of the radially outward movement the support sleeve 258 remains the connection between the space 266 and the pressure fluid chamber 264 still open. The radial breakthrough 260 becomes however with increasing radial displacement towards the outside and finally completely closed, so that the trapped in the pressure fluid chamber 264 Pressure fluid through the continued movement of the plate-shaped Elements 254 is pressurized. The pressure increase in the pressure fluid chamber 264 and thus that of the sliding block 218 stabilizing force exerted on the eccentric ring 214 depends on the speed at which the support sleeve 258 is moved radially outwards, i.e. speed-dependent. Through suitable design or adaptation of channels 268 and 270 may have the stabilizing function energetically optimized so that the stabilizing Function in a certain speed band in which it is on stabilization is particularly popular, held at its highest becomes. In any case, the order should be made that the dynamic pressure in the pressure fluid chamber 264 is reduced, when the main compression pressure from piston 222 in the pump chamber 230 is built.

Since there are several radial pistons 222 and thus several plate-shaped evenly distributed over the circumference Elements 254 always a pressure fluid chamber 264 in one State in which this chamber is reduced, so that there is a stabilizing pressure over the throttles 268, 270 builds up, the eccentric ring 218 independently of the Pressure conditions in the pump chamber 230 stabilized positively and torsional / tilting vibrations of the eccentric ring are effectively avoided.

The embodiment according to FIG. 5 differs from the embodiment according to Figures 3 and 4 by the design of plate-shaped element 354 and the support sleeve 358. According to this embodiment, the Support sleeve 358 with its end face 374 on the plate-shaped Element 354 such that at least between the contact surfaces a throttle channel remains. The plate-shaped element 354 is connected to the pump piston 322 in the center and holds the slide shoe 318 like a clip with sections 355 firmly. Again, the support sleeve 358 has at least one radial opening 360 equipped in the guide collar, see above that the pressure fluid chamber 364 in the area of bottom dead center the support sleeve 358 and thus the piston 322 with Pressure fluid can be filled, which is then via a throttle channel arrangement between the end face 374 of the support sleeve 358 and the plate-shaped element 354 displaceable into the environment is, making a radially inward Stabilizing force built up on the eccentric ring 314 can be.

The embodiment according to FIG. 6 is described below. again for those elements that the Components of the exemplary embodiments described above corresponding reference numerals are used, which is preceded by a "4".

Apart from the fact that in this embodiment the Suction valve 431 with radial alignment in the cylinder insert 426 is integrated, which is in further deviation via a support ring 476 on a shoulder of the pump housing 410 is also the plate-shaped element 454 designed differently. In detail, the plate-shaped element formed by an annular disc to which an axial collar 456 is formed, via which an axially fixed connection to the Piston 422 is made. Between the end face 474 of the Cylinder insert 426 and the plate-shaped element 454 At least one radial channel 478 is formed, which in one Radial channel 480 opens into the support sleeve 458. The radial channel 480 is under the same pressure as room 466, from the at least one radial opening 460 Pressurized fluid in the pressurized fluid space between the end face 474 and the plate-shaped element 454 can flow when the support sleeve 458 has assumed its inner dead center position at the latest at this point in time. This one too In the embodiment, the support sleeve 458 follows the movement the eccentric ring 414 under the action of the compression spring 435, which is supported on a radial shoulder 472 of the support sleeve 458, i.e. above a collar section 482 with which the slide shoe 418 is enclosed.

With the reference numeral 484 are elastic dowel pins referred to, with which the shoe 418 with the support sleeve 458 on the one hand and with the plate-shaped element 454 and the piston 422, on the other hand, is clamped together elastically and without play can be, so that relative movements of this Components to each other and thus early wear in these areas can be excluded.

In the inner dead center position is also in this embodiment between the end face 474 of the cylinder insert 426 and the top of the plate-shaped element 454 delimits a pressure fluid chamber 464 on which after closing of the radial breakthrough 460 pressure fluid through the Radial breakthrough 480 and later through at least one Radial channel 478 is displaceable, which results in the pressure fluid chamber 464 depending on the speed the eccentric ring 414 stabilizing pressure builds up. By suitable Design of the throttle channels and in particular the radial channel 480 the stabilizing force can be used to energetic Optimization of the eccentric ring stabilizing Control the device so that in selected operating states, for example in a certain central spectrum works with the greatest effect.

Finally, another embodiment is shown in FIG. 7 the stabilization device according to the invention of the eccentric ring described. The reference number this figure - as far as they are comparable elements like characterize in the previously described embodiments - preceded by a "5".

The peculiarity of this embodiment exists in that the support sleeve 558 is not on the piston insert here 526, but in a guide bore 515 of the pump housing 510 is performed. The pressure fluid chamber is designated 564 and it is located above the shoe 518 in the room where the return spring 535 is housed, which is on the head portion of the cylinder insert 526 on the one hand and on a driver plate or a support disc 554 supports on the other hand, which is axially fixed with piston 522 is connected. The plate-shaped element of the hydraulic displacement element arrangement is here from Slide shoe 518 formed.

Between the support plate 554 and the inner wall 584 there remains an annular gap 586, which is shown in FIG top dead center of the piston 522 and thus the Support sleeve 558 in the region of a radial opening 588 Support sleeve 558 comes to rest. The radial breakthrough 588 is in fluid communication with a chamber 567, in which in turn is a slight overpressure or ambient pressure prevails.

The support sleeve 558 has - like the support sleeves of the previous one described embodiments - at least one other Radial breakthrough 560, above which when the control edge is reached 590 the pressurized fluid chamber 264 quickly with pressurized fluid can be filled from room 567. The support sleeve also has 558 an annular collar 592 with which the sliding shoe 518 engages behind becomes. In this way, the shoe 518 can it is moved radially inward by piston 522, which Take the support sleeve 558 with you. The operation of the stabilization device for the eccentric ring 514 is as follows:

FIG. 7 shows the piston 522 in the top dead center position. Under the action of the spring 535 follows Sliding shoe 518 of the support surface 516 of the eccentric ring 514, when the eccentric section moves. The pressure fluid chamber 567 increases while pressurized fluid from the room 567 over the radial opening 588 and the annular gap 586 flows. Finally, the bottom dead center position the at least one radial opening 560 opened, so that the pressure fluid chamber 567 completely with Pressure fluid is filled. If the support surface 516 is radial moves outward, the support sleeve 558 is moved and the control edge 590 is gradually closed. That in the pressure fluid chamber 564 above the shoe 518 trapped pressure fluid is now the further movement of the Support sleeve 558 is pressurized radially outwards because this pressure fluid only through the radial opening 588, i.e. can flow throttled. The dynamic pressure in the pressure fluid chamber 564 acts on the sliding shoe 518, which thus also against a speed-dependent radial preload the flattened support surface 516 of the eccentric ring 514 is pressed, whereby the latter can be stabilized. Because with several, evenly distributed over the circumference Radial piston and thus with several evenly over the circumference distributed stabilizing devices for the eccentric ring, there is always a pressure fluid chamber 564 in a phase in which the volume is reduced so that the Stabilizing force are exerted on the eccentric ring can.

In the embodiments of FIGS. 8 to 11, the Combination of support sleeve and cylinder insert together with a slot control device and a check valve the function of a pre-feed pump for the radial piston pump To run. In the following description of this Exemplary embodiments are the components that make up the components correspond to the previously described embodiment or are comparable with them, again with similar ones Provide reference numerals, however, a "6" (Fig. 8), a "7" (Fig. 9), an "8" (Fig. 10) and a "9" (Fig. 11) is prefixed.

The embodiment shown in Fig. 8 with stabilizing device and pre-feed pump has a similar one Construction like the device shown in Fig. 6. However is in the embodiment of Fig. 8 no throttle bore analog the bore 480 of Fig. 6 provided. The fluid will in this embodiment supplied via a suction channel 632 and via a pressure channel 637 from the room 666 and the pressure fluid chamber 664 discharged. A not shown Check valve in pressure channel 637 or another Check valve ensures that a certain pressure in the pressure fluid chamber prevails and thus the eccentric ring 614 is stabilized.

On the underside of the support ring 676 is a sealing sleeve Arranged 638, the slots extending in the axial direction 639 has that in cooperation with the support sleeve end 659 the fluid flow depending on the piston position from suction channel 636 to pressure channel 637 or interrupt.

The following is the operation of that shown in Fig. 8 Radial piston pump described:

When the piston 622 together with the support sleeve 658 from the top dead center shown in Fig. 8 from the eccentric ring 614 via the spring 635 to its bottom dead center fluid is drawn in, fluid is sucked in via the suction channel 632. This enters room 666. Now opens between the radial opening 660 and the end face 674 narrow gap, fluid also gets into the pressure fluid chamber 664. The sealing sleeve 638 is to this Time of the support sleeve end 659, the sliding shoe 614 is turned away from. With further movement of the piston Fluid reaches the bottom dead center 622 via the slot 639 into space 690 radially outside the end of the support sleeve 659, the check valve in the pressure channel 637 closed is.

At bottom dead center there are rooms 666, 690 and the pressure fluid chamber 664 its maximum volume.

Now the piston 622 of the radial piston pump from the lower Moved to top dead center, the support piston displaces 658 the fluid in room 690 into the pressure channel 637, the design of the slots this effect can support and open at a certain amount, which is determined by the spring force of the check valve, the connection to the suction valve of the pump section with radial piston function. The fluid present in room 666 becomes by the displacement movement of the hydraulic displacement element 654 pressurized (radial bore open) and then comes together with those in the pressure fluid chamber 664 existing fluid via a throttling device, from the slots 639 in the sealing sleeve 638 and through the support sleeve end 659 is formed into the space 690. This fluid is the pressure valve 637 the suction valve of the pump section with radial piston function. The arrangement of the slots 639 determines the filling and fluid delivery times and the stabilization pressure for the eccentric ring.

Finally when the radial breakthrough 660 closed is, the fluid in the pressure fluid chamber is compressed and exerted increased pressure on the eccentric ring 614, which holds the eccentric ring in place and a shift of prevents this. Get to the top section in Fig. 8 from the end of the support sleeve to those located in the radial direction Section of the slots 639 in the sealing sleeve 638, see above the fluid connection between the suction channel 632 and the Pressure channel 637 interrupted. The support piston end slides however, the fluid present in room 690 from this room whereupon the pre-funding is completed.

The check valve ensures that there must be a certain pressure in room 666 before fluid is dispensed.

Similarly, the device of Fig. 7 shows an embodiment with an integrated feed pump modify. This is shown in Figure 9. The devices the latter two figures differ in that in the device shown in Fig. 9, the radial breakthrough 588 is missing and that instead a suction channel as well a pressure channel with a check valve are provided.

The radial opening 760 and a control edge 590 form 9, a slot control device, with which the fluid connection between the suction channel and the pressure channel is interrupted or permitted. A throttling device analogous to the support sleeve end 659 together with the sealing sleeve 638 is in this embodiment not provided. But ensures the spring force of the Check valve 791 from that when the piston moves 722 a certain pressure in from bottom to top dead center the pressurized fluid chamber 764 before fluid communication between the pressure channel of the pre-feed pump and the Suction port of the pump section with radial piston function is released.

10 and 11 are further exemplary embodiments for a radial piston pump device with stabilizing device and pre-feed pump, the embodiment 8 are similar.

10 differs from 8 in that in Fig. 10 slots 861 on the Support sleeve are formed and the sealing sleeve 838 none Has slits. The structure and function of the device from Fig. 10 otherwise correspond to the structure and Function of that of Fig. 8. An advantage of this embodiment is that in the pressure stroke longer sealing lengths can be realized.

The device in FIG. 11 shows an example Realization of the check valve. If in the pump housing a parting line is provided on the flange side, it is advantageous, the flat seal on the flange also as a check valve to use. Here, tabs 993 on one Flat gasket 992 made of sheet metal may be provided. By this arrangement reduces the number of components and thus get a cheaper pump.

Furthermore, it is also possible if the housing separation joint is not present the check valve in the already provided Integrate pressure screw. This is exemplary shown in Fig. 8.

Of course, within the scope of the specialist's knowledge, there are deviations from those described Embodiments possible without the claims leave certain protection area. For example, additional, measures familiar to the expert are taken in order to already during of enlarging the pressure fluid chamber to ensure that this is over the throttle channel arrangement with pressure fluid crowded. It may also be advantageous to use the throttle cross section for the throttled displacement of the pressure fluid changeable from the pressure fluid chamber into a low pressure area to shape in this way the energetic Optimizing the generation of the stabilizing force for different Ensure speed spectra.

The invention thus provides a device for stabilization the eccentric ring of a radial piston pump with several, driven by a common eccentric shaft Pistons, each in a cylinder insert fixed in the pump housing are slidably guided and flattened Support the support surfaces of the eccentric ring, the is rotatably mounted on an eccentric of the eccentric shaft. In order in all operating states of the pump and thus in particular in the states in which a Undersupply exists to prevent torsional / tilting vibrations of the eccentric ring is a hydraulic Displacement element arrangement provided with the the eccentric ring in every movement phase of the pump active pressurization of the displacement element arrangement is stabilizable.

With the embodiments of FIGS. 8 to 11 a radial piston pump is provided, in which a prefeed pump is integrated and with a stabilized contact between the piston and the eccentric ring is possible.

Claims (32)

1. Device for stabilizing the eccentric ring of a radial piston pump having several pistons each driven by a common eccentric shaft, each of which is guided in a cylinder insert (26; 226; 426; 526) immobilized in a pump housing (10; 110; 210; 310; 410; 510) so as to be slidingly displaceable, and which are supported on flattened support surfaces of said eccentric ring which is rotatably mounted on a cam of said eccentric shaft, said device including at least one support member assembly for biasing a stabilization member, which is supported against said pump housing, into planar contact with a stabilization surface of said eccentric ring independently of the pressure conditions in the pump chamber (30; 230; 430), characterized in that in order to prevent rotational/pivotal vibrations of said eccentric ring (14; 114; 214; 314; 414; 514) in suction throttling operation of said radial piston pump, a hydraulic displacement member assembly (40; 140-1 to 140-3; 254; 354; 454: 514) is provided whereby said eccentric ring is stabilized in each phase of movement of said pump through active application of pressure by said displacement member assembly.
2. Device according to claim 1, characterized in that said displacement member assembly includes at least one cup-shaped piston (40; 140-1 to 140-3) which is supported by its bottom (42) on an associated stabilization surface (44) of said eccentric ring (14; 114) and which constantly receives application of pressure on its inside.
3. Device according to claim 2, characterized in that a spring pressure force (49) is connected in parallel with pressure stabilization.
4. Device according to claim 3, characterized in that inside said cup piston (40; 140-1 to 140-3) a pressure spring (49; 149) is received which is supported on a screw plug (50) wherein an opening (47) for supplying hydraulic medium under bias pressure (P2) is formed.
5. Device according to any one of claims 1 to 4, characterized in that at least three hydraulic displacement members (140-1 to 140-3) are provided, which co-operate with separate stabilization surfaces (144-1 to 144-3) formed at a preferably regular angular distance from each other on said eccentric ring (114) (Fig. 2).
6. Device according to claim 1, characterized in that said hydraulic displacement member assembly comprises several dish-shaped members (254; 354; 454; 554) associated to different pistons which are at an angular distance from each other, said dish-shaped members being connected to the radially inner portion of the associated piston (222; 322; 422; 522) so as to be secured against displacement, forming part of a pressure force chain to the associated support surface (216; 316; 416; 516) of said eccentric ring (214; 314; 414; 514), and each forming, in co-operation with the related cylinder insert: (226; 326; 426; 526) and a support bush (258; 358; 458; 558) which is movable jointly with said dish-shaped member, a pressure fluid chamber (264; 364; 464; 564) from which the fluid trapped therein is displaceable in a throttled manner.
7. Device according to claim 6, characterized in that said support bush (258; 358; 458; 558) has a radial opening (260; 360; 460; 560) whereby said pressure fluid chamber (264; 364; 464; 564) may be filled with fluid from the surroundings in the range of the bottom dead center of the piston movement.
8. Device according to claim 6 or 7, characterized in that said support bush (258; 358; 458) is fittingly guided on the outer surface of said cylinder insert (226; 326; 426).
9. Device according to claim 8, characterized in that said support bush (258; 358; 458) is biased towards said support surface (216; 316; 416) of said eccentric ring (214; 314; 414) by means of a helical pressure spring (235; 335; 435).
10. Device according to claim 9, characterized in that said support bush (358) is axially supported on said dish-shaped member (354), and that a throttle passage arrangement is formed in the contact range between support bush (358) and dish-shaped member (354) (Fig. 5).
11. Device according to claim 9, characterized in that said support bush (258; 458) is axially supported on said dish-shaped member (254; 454) while enclosing the latter by means of a collar in which at least one throttle bore (270; 480) is formed (Figs. 4 and 6).
12. Device according to claim 11, characterized in that said support bush (258; 458) encloses a sliding block (218; 418) on which the associated piston (222; 428) is supported.
13. Device according to claim 11 or 12, characterized in that said dish-shaped member (254) includes at least one axial opening (268) whereby a throttled fluid connection towards a space in front of said throttle bore (270) is provided (Fig. 4).
14. Device according to claim 11 or 12, characterized in that said dish-shaped member (454) rests substantially flat on said sliding block (418) and, in co-operation with the axially opposed end face (474) of said cylinder insert (426), defines a throttle passage arrangement (478) which opens into said throttle bore (480) of said collar of said support bush (458) in the top dead center position of said piston (422) (Fig. 6).
15. Device according to any one of claims 11 to 14, characterized in that said support bush (458) is elastically braced (pins 484) with said sliding block (418).
16. Device according to claim 6 or 7, characterized in that said support bush (558) is fittingly guided in said pump housing (510) by means of a bore (515) coaxial with said piston (522).
17. Device according to claim 16, characterized in that throttled displacement of fluid from said pressure fluid chamber (564) takes place via another radial opening (588) formed in said support bush (558).
18. Device according to claim 17, characterized in that displacement of fluid from said pressure fluid chamber in the range of the top dead center takes place via a radial gap (586) between a driving plate (554) for said piston (522) and said support bush (558).
19. Device according to any one of claims 16 to 18, characterized in that said support bush (558) positively holds a sliding block (518) on which the associated piston (522) is supported and which forms said dish-shaped member, wherein said driving plate (554) forms the counter-surface for a helical pressure spring (535) supported on said cylinder insert (526).
20. Device according to any one of claims 1 to 19, characterized in that it is fed by a low-pressure pump.
21. Device according to any one of claims 1 to 20, characterized in that active application of pressure is energetically optimized in dependence on the speed range of said pump with a view to low power losses.
22. Device according to any one of claims 1 to 21, characterized in that said high-pressure pump is constituted by a radial jet pump.
23. Device according to any one of claims 1 to 22, characterized in that said displacement member assembly (654, 754, 854, 954) forms part of a prefeed pump for feeding said pump chamber (630, 830, 930).
24. Use of the device according to any one of claims 1 to 23 in a pressure fluid supply system, in particular in a fuel injection system whereby the pressure (P₁) in a common high-pressure line, in particular in a common-rail (34) to which individual consumers, in particular injection valves are connected, may be regulated in accordance with the current pressure fluid demand in dependence on operation parameters of the system, wherein a fluid flow rate limiting means is associated to said high-pressure pump for adaptation of the pressure (P₁) in said common high-pressure line (34) to the pressure fluid demand of the consumers, said fluid flow rate limiting means including at least one actuation member modifiable by means of an actuation signal which represents the current pressure fluid supply situation in the common high-pressure line (34).
25. Device according to claim 8 or 9, which furthermore includes:

    a pressure passage (637, 837) formed in said cylinder insert (626, 826) and/or on said pump housing (610, 810) adjacent said cylinder insert (626),

    a suction passage (632, 832) provided on said pump housing (610, 810) between said eccentric ring (614, 814) and said pressure passage (637, 837),

    slot control means (638, 659; 838, 861) for admitting the flow of fluid between said suction passage (632, 832) and said pressure passage (637, 837) in the range of the bottom dead center of the piston movement, and for interrupting the flow of fluid in the range of the top dead center of the piston movement, and

    a check valve in said pressure passage (637, 837).
26. Device according to claim 25, wherein said slot control means comprises a seal sleeve (638) seated on a support bush end (659) of said support bush (658), said seal sleeve being located on said pump housing (610) upstream from said pressure passage (637) and including at least one slot (639).
27. Device according to claim 25, wherein said slot control means comprises a seal sleeve (838) located on said pump housing (810) upstream from said pressure passage (837) and seated on a support bush end (859) of said support bush (858) having at least one slot (861).
28. Device according to any one of claims 25 to 27 which includes a flange-side housing parting line, wherein said check valve is formed by sheet-metal tabs of a flat packing of sheet metal on the outlet bore of said pressure passage (637, 837).
29. Device according to any one of claims 25 to 27 without a flange-side housing parting line, wherein said check valve is integrated into a pressure bolt of the support ring of a pressure chamber insert.
30. Device according to claim 16, characterized in that said support bush (258; 358; 458; 558) has a radial opening (260; 360; 460; 560) through which said pressure fluid chamber (264; 364; 464; 564) may be filled with fluid from the surroundings in the range of the bottom dead center of the piston movement, said device further including:

    a pressure passage (737) formed in said cylinder insert (726) and/or on said pump housing (610) adjacent said cylinder insert (726),

    a suction portion (732) provided on said pump housing (710) between said eccentric ring (714) and said pressure passage (737),

    a slot control means (760, 790) for admitting the flow of fluid between said suction portion (732) and said pressure passage (737) in the range of the bottom dead center of the piston movement, and for interrupting the flow of fluid in the range of the top dead center of the piston movement, and

    a check valve in said pressure passage (737).
31. Device according to claim 30, characterized in that said support bush (758) positively holds a sliding block (718) on which the associated piston (722) is supported and which constitutes said dish-shaped member, with said driving plate (754) forming the counter-surface for a helical pressure spring (735) which is supported on said cylinder insert (726).
32. Device according to claim 30 or 31, wherein said slot control means includes said radial opening (760) and said control land (790).

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