WO2009062783A1

WO2009062783A1 - Pump assembly for synchronous pressurization of two fluid circuits

Info

Publication number: WO2009062783A1
Application number: PCT/EP2008/062919
Authority: WO
Inventors: Rene Schepp; Norbert Alaze
Original assignee: Robert Bosch Gmbh
Priority date: 2007-11-16
Filing date: 2008-09-26
Publication date: 2009-05-22
Also published as: DE102007054808A1; CN101855452B; EP2220373A1; JP2011503428A; CN101855452A; JP5323080B2; US20100322810A1

Abstract

The invention relates to a pump assembly (10) for the synchronous pressurization of two fluid circuits, comprising two internal gear pumps (11, 11') disposed together in a pump housing (12) and rotationally driven by the drive shafts (16) thereof, the pinions (19, 19') of said pumps being located in the associated pump chamber and engaging in the internal gear (21, 21') thereof. The pump chambers of the internal gear pumps (11, 11') are separated from each other by a common separating wall (15), which is designed as a separate housing part and engages in a hollow cross-section of a housing part (13) forming the circumferential wall of one of the internal gear pumps (11, 11'). Suction channels (24, 24') and pressure channels (25, 25') associated with the internal gear pumps (1, 11') transition into a radially extending longitudinal section in the pump housing (12) following an axial longitudinal section in the lateral boundary wall of the associated pump chamber. According to the invention, the suction channel (24, 24') and the pressure channel (25, 25') of one of the internal gear pumps (11, 11') are integrated in the separating wall (15).

Description

description

title

Pump assembly for synchronous pressurization of two fluid circuits

State of the art

The invention is based on a pump assembly for the synchronous pressurization of two fluid circuits according to the preamble of independent claim 1.

Such a pump assembly is z. B. from DE 10053991 Al as so-called

Pump insert for a hydraulic, wheel slip-controlled vehicle brake system known, being supplied by the two internal gear pumps of the pump insert different brake circuits of the brake system with diagonal brake circuit distribution. The two internal gear pumps are separated from each other by a separately formed partition wall of the multi-part housing and are traversed transversely by a common drive shaft. On this drive shaft, the pinion of the two gear pumps are pushed and rotatably connected via a driver connection with her. In order to seal the pump chambers of the adjacent gear pumps against each other, two shaft seals are inserted into matched annular spaces of the partition bore at a distance from each other. If something passes through the thus sealed at both ends shaft passage some brake fluid, it is removed via a vent hole, which is arranged between the shaft seals under radial extent in the partition wall. To integrate the two internal gear pumps in the respective associated brake circuit each internal gear pump are further associated with a suction channel and a pressure channel, which are seen in the axial direction at opposite end portions of the pump assembly, extending substantially radially and bending their end portion in the suction or pressure side of the associated pump room open. Due to their lateral arrangement, the pairs of channels belonging to the internal gear pumps have, in addition to the front ends of the pump assembly, an NEN considerable distance from each other, which must also be considered in the design and dimensioning of the pump housing.

Disclosure of the invention

The pump assembly according to the invention with the features of independent claim 1 has the advantage that the axial distance of the pairs with suction and pressure channel of the internal gear pumps can be significantly reduced from each other. This allows a more compact design of the pump assembly can be realized and possibly accompanied by a simplified design of the line system for the two FIu- idkreise. The suction channel and the pressure channel can also be arranged in a technically simpler manner positionally accurate in the partition, since the partition serves as an axial thrust washer for the wheelsets of the pump. So the partition is accessible from all sides before installation in the pump housing, which z. B. a spa- nende processing for generating or editing the hollow channels significantly easier.

Also, the enclosing housing parts no longer at a distance of their faces from each other at the periphery of the partition by means of rolled-up areas or the like. Be joined, but the dividing plane can extend next to the partition wall and the annular end faces of the housing parts to be joined together can be added to shock. As a result, the connection intensity of the hollow cylindrical housing parts can be substantially improved so that the pump assembly does not require the insertion into a pump housing that stabilizes it.

The measures and refinements recited in the dependent claims advantageous refinements and improvements of the independent claim 1 pump assembly are possible.

Particularly advantageously, the suction channels and the pressure channels of both internal gear pumps are integrated into the partition. As a result, the pressure channels and the suction channels of both internal gear pump are very close to each other, which is a correspondingly compact

Design of the pump assembly makes possible. In addition, if the leakage channel integrated into the partition, it can be significantly shortened and does not require its own outlet opening when it opens into a drain hole of one or both suction channels of the partition. Are all the fluid passages of the pump assembly directly connected to the pump chambers or connected to them, together with the leakage line, nal within the partition, then the fluid channels with little manufacturing effort can accurately fit into the workpiece "partition" or edit easily cast in fluid channels.

Despite the integration of two suction channels and two pressure channels, the dividing wall can have a relatively small thickness if the four fluid channels are arranged substantially in the same cross-sectional area of the dividing wall. In order for this to be possible, the fluid channels in the dividing wall can be arranged offset from each other by 90 degrees by arranging the internal gear pumps of the pump assembly rotated 180 degrees counter to one another. This has the positive side effect that largely cancel out the acting in the opposite direction compressive forces in the internal gear pumps.

If a valve arrangement is provided in the line system of one of the fluid circuits to be supplied, this arrangement can be arranged directly in the associated fluid channel

Be integrated partition. This valve arrangement may comprise one or two valves in one or both fluid circuits to be charged. A technically particularly useful equipment of the fluid circuits or fluid circuits, each with two valves is present when a pressure relief valve in the suction channel or the suction channels of the partition and a pressure relief valve in the pressure channel of the partition wall are arranged. For this valve arrangement thus an already existing space is used within the partition, so that it can be dispensed with an external arrangement of the valves in the system of the associated fluid circuit. This results in a corresponding space savings outside the pump assembly and possibly a simplification of the connected line system.

The partition consists in a preferred embodiment of a cylindrical disc with plane-parallel end faces which are perpendicular to the central longitudinal axis of the disc and parallel to each other, and is pressed into a cylindrical hollow cross-section of the associated housing part. If the flat faces are ground, which is possible due to the disc shape cost-effective with high surface quality, they can serve directly as contact surfaces for the gear sets. By pressing the disc in a cylindrical hollow section, z. B. with a press fit, can ensure a position-securing mounting position of the disc in the housing without additional fasteners. The press-in process must be carried out so that the radial ends the fluid channels of the disc are aligned after the pressing process to corresponding fluid channels in the housing. By choosing a suitable interference fit, if necessary, a liquid-tight connection between the outer circumference of the disk and the inner circumference of the housing can be created without additional sealing means.

The pressed-in dividing wall can advantageously be supported axially between opposite annular end faces of two housing parts, the outer diameter of one of the housing parts largely corresponding to the outer diameter of the dividing wall. The adapted in the diameter of the partition tubular end portion can then, similar to the dividing wall, be pressed or inserted into the larger tubular end portion of the other housing part, after which there is a telescopic length overlap of the pipe ends. With sufficient axial security resulting from the assembly of the hollow housing parts and the partition a very stable composite.

In order to ensure reliable sealing of the tooth gaps of the wheelsets in the Innenzahnrad- pumps on their facing away from the partition end faces, at the ends of the pump assembly in each case a pressure piece from a usual for plungers plastic material may be arranged on the one hand and on the front sides of the associated wheelset on the other hand, axially supported on the opposite bore wall of the pump chamber. Preferably, the plungers are each structurally associated with an associated bearing sleeve for the drive shaft, resulting in a desirable reduction in the number of parts in the pump assembly. The bearing sleeve itself can be formed integrally with the pressure piece and even form a plain bearing. Alternatively, however, the bearing sleeve can accommodate or enclose a roller bearing or bearing shells of a sliding bearing.

An advantageous embodiment of the invention is illustrated below with reference to drawings and described with reference to the drawings.

Brief description of the drawings

Fig. 1 shows a schematic central longitudinal section through a pump assembly according to the invention.

Fig. 2 shows a pump chamber of the pump assembly of Fig. 1 in side view. 3 shows a vertical section through a partition wall of the pump assembly according to the section line III-III in FIG. 1.

Embodiment of the invention

As can be seen from FIG. 1, a pump assembly 10 comprises two internal gear pumps 11 and 11 ', which lie laterally next to one another and are arranged in a common pump housing 12. When installed, the pump assembly 10 is part of a not shown pressure control device for a vehicle brake system with diagonally split brake circuits, the internal gear pumps 11 and 11 'are each responsible for the pressure supply of the brake circuits in the course of known as such brake interventions for ABS or ESP applications. The common pump housing 12 is composed on the outside of two pot-like hollow housing parts 13 and 14, which each define a pump space of the internal gear pump 11 or 11 'on three sides and are joined under length coverage of their end regions. Between these housing parts 13 and 14, a partition wall 15 is inserted as an inner housing part, which limits the pump chambers of the two internal gear pumps 11 and 11 'with its end faces on the fourth side. The partition wall 15 consists of a cylindrical disc with plane-parallel end faces, which is pressed into a cylindrical hollow cross-section of the associated housing part 13.

The drive of the two internal gear pumps 11 and 11 'takes place via a common drive shaft 16, which is driven in rotation by an externally flanged DC motor, wherein the drive shaft 16 via a sealed shaft passage in the

Housing 12 is inserted and passes through coaxial bearing bores, which are recessed from the end faces of the housing parts 13 and 14 and from the partition wall 15. At the central bearing point, the drive shaft 16 is rotatably mounted to slide directly in the bore of the partition wall 15, while the drive shaft 16 is rotatably mounted rotatably on the lateral bearings via a bearing sleeve 17 and a bearing sleeve 17 'made of plastic.

The bearing sleeves 17 and 17 'are each formed as a hollow cylinder and lie positively between the circumference of the drive shaft 16 and the associated bore wall of the housing part 13 and 14 respectively. Between the bearings, the drive shaft 16 passes through the bearing sleeve 17 or 17 'in each case a pressure piece 18 or 18', which is formed integrally with the associated bearing sleeve 17 or 17 ', then a central insertion opening in the associated pinion 19 and 19 'of the internal gear pumps 11 and 11' and finally an associated shaft seal 20 or 20 ', in an associated, stepped extension of

Bearing bore for the drive shaft 16 is pressed in the partition wall 15.

As can be seen in connection with the side view of the pump chamber of the internal gear pump 11 of FIG. 2, passes through the drive shaft 16 with an approximately hexagonal cross-section, which has gently rounded edges, a matching hollow cross-section of the pinion 19, whereby a rotationally secure driver connection between the Pinion 19 and the drive shaft 16 is given. The external teeth of the pinion 19 meshes in the internal toothing of a ring gear 21, which in turn is rotatably mounted with the round outer periphery in a bore portion of the associated housing part 13. The toothing engagement is located exactly in the middle of the upper part of the

Internal toothing of the ring gear 21, whereby the head circles of pinion 19 and ring gear 21 define a total crescent-shaped annular space. This annulus is based on the vertical center plane of the wheel, in which the axes of rotation of pinion 19 and ring gear 21 extend, designed mirror-symmetrically. In the crescent-shaped annular space, a filler piece 22 is pivotably mounted by means of a centrally arranged axle pin 23. However, the pivoting mobility is limited to a minimum, since the Au- ßenumfangsseite the filler 22 with little play on the covered tooth tips of the internal teeth of the ring gear 21 and the inner peripheral side of the filler 22 with little play on the overlapped tooth tips of the pinion 19. In the partition wall 15 is also on the right suction side of the internal gear pump 11 a suction channel 24 and on the left pressure side to recognize an associated pressure channel 25 for the brake fluid.

Will now completely filled with brake fluid and vented internal gear pump 11, the drive shaft 16 z. B. by means of an electric gear motor rotated in the clockwise direction, the pinion 19 rotates synchronously with and also the ring gear 21 is rotated due to the meshing engagement with the pinion 19 in the same direction. Since the tooth gaps covered by the filling piece 22 are sealed on one end face by the pressure piece 18 acted upon by a corresponding axial force and by running on the dividing wall 15 on the opposite end face, the hollow volumes of brake fluid received by the tooth spaces can be filled sufficiently. Seal the tooth tips relative to the filler 22 are transported under appropriate pressure increase from the suction channel 24 to the pressure channel 25 of the internal gear pump 11. The sealing between the tooth tips and filling piece 22 required for this purpose comes about solely on the basis of a defined circumferential clearance of the filling piece 22, through which a pressure distribution over the circumferential extension of the filling ring 22 during operation is achieved

Filler 22 results, which leads to a sufficient rotational force of the filler 22 about the central longitudinal axis of the axle 23. Upon rotation of the pinion 19 in a clockwise direction thus also results in a rotational force on the filler 22 in the clockwise direction, whereby the inner peripheral side of the filler 22 from the lever arm to the left of the axle pin 23 on the ü- covered teeth heads of the pinion 19 and the outer peripheral side of the lever arm to the right of the axle pin 23rd is depressed to the tooth tips of the ring gear 21. As a result of the Verzwängung the lever ends of the filler 22 between the teeth of pinion 19 and ring gear 21 results in an opposite same contact pressure of the filler 22, as required for adequate sealing between the overlapped tooth heads and the filler 22.

As already explained, the internal gear pump 11 'is driven by the drive shaft 16, as well as the pinion 19' penetrated by the drive shaft 16 and rotatably connected thereto via one of the pinion 19 corresponding driver connection. The geometry of the internal gear pump 11 'as such is largely consistent with that of internal gear pump 11, wherein the wheel set of pinion 19' and ring gear 21 'are arranged rotated by 180 degrees relative to the wheel set of pinion 19 and ring gear 21. Because of this by 180 degrees against each other rotated Radsatzanordnung in the internal gear pumps 11 and 11 ', ie an oppositely eccentric arrangement, the resultant of the pressure forces on the pressure side of the internal gear pump 11 and 11' act in opposite radial directions, as shown in FIG Arrows is indicated. Thus, these resulting radial forces largely cancel, which allows a more favorable dimensioning of the pump housing 12, as in the dimensioning of the same essentially only the forces acting through the axial displacement of the resultant moments must be considered constructive.

It is understood that in the oppositely eccentrically arranged internal gear pumps 11 and 11 'and the pressure pieces 18 and 18' and the filler pieces 22 and 22 'must be arranged rotated 180 degrees against each other. The same applies to the suction channel 24 'and the pressure channel 25', which are also integrated into the partition wall 15 and the pump chamber of the internal gear pump 11 'are open.

As can be seen in the sectional illustration through the partition wall 15 according to FIG. 3, the suction channel 24 opening into the pump chamber of the internal gear pump 11 and the associated pressure channel 25 lie essentially in the same cross-sectional plane as the opening into the pump chamber of the internal gear pump 11 ' Suction channel 24 'and the associated pressure channel 25'. In addition, they are arranged radially so far in the direction of the outer circumference that they can stand without detriment to the function under axial cover to the pressed-in shaft sealing rings 20 and 20 '. As a result, the partition 15 must have a total of only a slightly greater thickness than is required to integrate the axial and radial channel portion of the suction channel 24 and 24 'anyway. In the same cross-sectional area, a leakage channel 26 is additionally arranged for removing brake fluid which has penetrated into the bearing bore of the dividing wall 15, which extends from the bearing bore of the dividing wall 15 between the shaft sealing rings 20 and 20 ', extends diagonally through the dividing wall 15 and into which two suction channels 24 and 24 'opens. Furthermore, it can be seen that in the suction channels 24 and 24 'are each a pressure reducing valve 27 and 27' and in the pressure channels 25 and 25 'are each a pressure relief valve 28 and 28' is arranged, wherein the arrangement is made so that all Valves 27, 27 ', 28 and 28' received within the partition wall 15 are located within partition wall cavities in each switching state.

The pressure relief valves 28 and 28 'are identical, oppositely arranged pressure relief valves of conventional design, in which a ball is in the flow path of the pressure channel and is pressed by the force of a return spring to its sealing seat. As soon as the fluid pressure at the sealing seat is greater than the spring force, the ball is displaced and the flow path of the pressure channel is thus released. The pressure channels 25 and 25 ', which are integrated with their radial length portion diametrically opposite each other near the periphery in the partition wall 15 are thus moved at a corresponding pressure against the spring load radially outward and thereby with the associated

Connected to the brake circuit fluidly or with a corresponding change in the pressure conditions by spring force again and thereby fluidly separated from the brake system. In contrast, the pressure reducing valves 27 and 27 'are formed as linear slide valves, which transversely through the radial flow path of the suction channel 24 and 24' with a tapered control section and are also used in the opposite direction. The sliding directions of the pressure reducing valves 27 and 27 'run parallel to one another and to the radial length sections of the pressure channels 25 and 25'. The slides of the pressure reducing valves 27 and 27 'are each held by the spring force of an associated helical compression spring in an axial starting position, which, however, the passage position of the pressure reducing valve 27 and 27' corresponds. The helical compression spring is in each case supported on the annular end face of a piston section adjoining the control section, which is slidably guided under sealing in its bore of the partition wall 15, and the control section engages with an end region having a central bore in an associated blind hole bore of the partition wall 15 one. Now increases the fluid pressure in the suction channel 24 or 24 'over a predetermined limit, so the flowed into the blind hole presses the annular face of the control section and thus moves the piston of the pressure reducing valve 27 and 27' against the force of the return spring, wherein the flow path the suction channel 24 or 24 'is increasingly moved from the advancing control section and thereby causes a corresponding throttling of the fluid flow. In the present case, the assignment of the internal gear pumps 11 and 11 'to brake circuits of a brake system, the components of the pressure reducing valves 27 and 27' are coordinated so that a pressure limit of about 10 bar on the suction side of the internal gear pumps 11 and 11 'can not be exceeded. As a result, unnecessary frictional forces in the internal gear pumps 11 and 11 'can be avoided, which would be detrimental both in terms of the efficiency of the pump assembly 10 and in terms of their wear. If fluid from the suction channel 24 or 24 'at the sealing plane of the pressure reducing valve 27 or 27' over into the guide bore, so it can flow together with fluid from the leakage channel 26, since the guide bore to the periphery of the partition wall 15 is open and thus additionally serves as a drain opening.

.o0o.

Claims

claims

1. pump assembly (10) for synchronous pressurization of two fluid circuits, the two together in a pump housing (12) arranged, via its drive shaft (16) rotationally driven internal gear pumps (11, 11 '), the pinion (19, 19') in the associated Pump chamber and are in meshing engagement with its ring gear (21, 21 '), wherein the pump chambers of the internal gear pumps (11, 11') by a common partition (15) are separated from each other, which is designed as a separate housing part and in a hollow cross-section of the Peripheral wall of one of the internal gear pumps (11, 11 ') forming the housing part (13) engages, and wherein the internal gear pumps (11, 11') associated with suction channels (24, 24 ') and pressure channels (25, 25') for an axial length in the lateral Pass boundary wall of the associated pump chamber in a radially in the pump housing (12) extending longitudinal portion, characterized in that the suction channel (24, 24 ') and the Pressure channel (25, 25 ') of the Innenzahnradpumpen (11, 11') in the partition (15) are integrated.

Second pump assembly according to claim 1, characterized in that the suction channels (24, 24 ') and the pressure channels (25, 25') of both internal gear pumps (11, 11 ') in the partition wall (15) are integrated.

3. Pump assembly according to claim 1 or 2, characterized in that in the partition (15) a leakage channel (26) is integrated, which is fluidly connected to a drain opening of a suction channel (24, 24 ') in the partition wall (15).

4. Pump assembly according to claim 1 or 2, characterized in that each suction channel

(24, 24 ') and each pressure channel (25, 25') of the partition wall (15) are arranged in the same cross-sectional area thereof.

5. Pump assembly according to claim 1 or 2, characterized in that in at least one suction channel (24, 24 ') or pressure channel (25, 25') of the partition wall (15) is provided a valve arrangement.

6. pump assembly according to claim 5, characterized in that in each suction channel (24, 24 ') of the partition wall (15) a pressure reducing valve (27, 27') and in each pressure channel (25, 25 ') of the partition (15) a pressure relief valve (28, 28 ') are arranged.

7. Pump assembly according to claim 1, characterized in that the partition wall (15) is a cylindrical disc with plane-parallel end faces, which is pressed into a cylindrical hollow cross-section of the associated housing part (13).

8. Pump assembly according to claim 7, characterized in that the pressed-in partition wall (15) axially on an annular end face of the housing part (13) and on its opposite end face an annular end face of the subsequent housing part (12) are supported, wherein the tubular end portions of the housing parts ( 13, 12) are joined under telescoping length overlap.

9. Pump assembly according to claim 1, characterized in that the wheel sets of the internal gear pumps (11, 11 ') on their the pump assembly (10) facing end faces of an associated pressure piece (18, 18') are axially acted upon, the egg - ne bearing sleeve (17, 17 ') for the drive shaft (16) encompassed.

10. pump assembly according to claim 9, characterized in that the pressure piece (18, 18 ') and the bearing sleeve (17, 17') consist of plastic and are integrally formed.

.o0o.