EP2646689A2

EP2646689A2 - Internal gear pump

Info

Publication number: EP2646689A2
Application number: EP11788806.5A
Authority: EP
Inventors: Rene Schepp; Kornelius Loew
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2010-11-30
Filing date: 2011-11-24
Publication date: 2013-10-09
Also published as: DE102010062219A1; KR20130141564A; KR101859362B1; US20130330223A1; CN103429896B; JP2013543950A; JP5719451B2; WO2012072492A2; CN103429896A; US9039398B2; WO2012072492A3

Abstract

The invention relates to an internal gear pump (1). For hydrodynamic lubrication, the invention proposes wedge gaps (24) between axial discs (16) and a ring gear (2) and a pinion of the internal gear pump and/or bores (25) through the axial discs (16), said bores communicating with a suction region (8) of the internal gear pump (1) and, when the ring gear (2) and the pinion are driven in rotation, form a lubricating film between the axial discs (16) and the ring gear (2) and the pinion in a comparable manner to hydrodynamic lubrication of an axial plain bearing.

Description

Description title

Internal gear pump

The invention relates to an internal gear pump having the features of the preamble of claim 1.

State of the art

An internal gear pump is known from the patent DE 196 13 833 B4. It has two gears, namely a ring gear, which may also be referred to as an internal gear, and an external gear, which will be referred to as a pinion for clear distinction, on. Together, the ring gear and the pinion will be referred to as gears. The pinion is arranged eccentrically in the ring gear, so that the two gears mesh with each other on a peripheral portion. The two gears define a crescent-shaped pump space between them, which extends in the circumferential direction from a suction region to a pressure region of the internal gear pump. The pump space extends outside the peripheral portion in which the two gears mesh with each other. The pump chamber of such an internal gear pump is sometimes referred to as displacement space or simply as intermediate or free space. The ring gear limits the pump chamber to the outside, the pinion limits it to the inside. The suction area can also be regarded as an inlet and the pressure area as an outlet of the internal gear pump.

For the lateral boundary of the pump chamber, the known internal gear pump has on each end face of its two gears a so-called. Axialscheibe which abuts with its inner side facing the gears on the end faces of the gears and the pressure on their outside facing away from the gears is charged. The inside and the outside of the axial disc are their front sides (!). The axial discs should seal to the gears of the internal gear pump and the stationary axial discs should have a low friction to the rotating gears. The axial discs do not seal hermetically, leakage occurs between the axial discs and the gears. It is important to find a good compromise between a good sealing effect on the one hand and low friction on the other hand in each case between the axial discs and the gears. Disclosure of the invention

The internal gear pump according to the invention with the features of claim 1 has at least one Axialscheibe on an end face of the gears, namely the ring gear and the pinion, the internal gear pump, which is pressurized on an outer side and with its inner side against the end faces of

Gears of the internal gear pump is pressed. The internal gear pump according to the invention preferably has two axial disks, namely an axial disk on each end face of the gear wheels, which are pressed against the end faces of the gearwheels of the internal gear pump by pressurizing the outside with their inner sides. The invention provides a lubricant supply from the suction region of the internal gear pump between the axial disc / s and the gears of the internal gear pump. During operation of the internal gear pump, the rotating gears of the internal gear pump, that is, the ring gear and the pinion, convey liquid from the suction region, that is, the inlet of the internal gear pump, between the rotating gears and the stationary one

Thrust washer / n. The liquid conveyed as a film on the faces of the gears of the internal gear pump between the gears and the thrust washer / n is the fluid conveyed by the internal gear pump, it is used as a lubricant. The process is comparable to the lubrication of a hydrodynamic axial plain bearing. The invention improves lubrication between the fixed axial disc (s) which is pressurized on outer sides and thereby pressed with their inner sides against the rotating gears of the internal gear pump and the rotating gears. The friction between the toothed edges and the / the axial disc / s and wear is reduced, increases the life and efficiency of the

Internal gear pump improved. During operation of the internal gear pump If the invention avoids mixed friction or even dry friction between the rotating gear wheels of the internal gear pump and the stationary axial disks pressed against the gears from outside, the invention reduces the risk of such mixed or dry friction, which increases friction and wear, and also Efficiency and life reduced.

Only at standstill and start of the internal gear pump may cause mixed or dry friction between the gears and the / the axial disc / s, the invention improves and accelerates a lubricating film structure between the gears and the axial discs when starting the internal gear pump.

The internal gear pump according to the invention can both a so-called. Sickle pump with a sickle, ie a usually sickle-shaped body in the pump space between the ring gear and the pinion, on the inside of tooth heads of teeth of the pinion and on the outside of tooth heads of the teeth

Sliding along ring gear, as well as a so-called. Internal gear pump be without such a sickle. The outer side (s) of the axial disc (s) may be filled with fluid from the pressure area, as is known in the art. H. the outlet of the internal gear pump are applied to press the axial disc / s against the gears of the internal gear pump.

The dependent claims have advantageous refinements and developments of the invention specified in claim 1 to the subject. An embodiment of the invention provides a lubricant channel in the / the axial disc / n as a lubricant supply, which communicates with the suction region of the internal gear pump and opens on the inside of the axial disc / n on an end face of the ring gear and / or the pinion. The lubricant passage may be distributed to both gears or there may be two (or more) lubricant passages.

A development of this embodiment of the invention provides that the lubricant channel passes through the axial disc / n from the outside to the inside, for example, forms one or more holes or the lubricant channels through the axial disc / n. Claim 4 provides for the formation of a kind of wedge gap between the / the axial disc / n and one or both gears of the internal gear pump, which tapers starting from the suction in a rotational direction of the gears and thus in a conveying direction of the internal gear pump. In order to form the wedge gap, the axial disk (s) has / has an inclined surface, which in the suction region of the internal gear pump has a distance from the internal gear pump gears, which decreases in the direction of rotation of the gear wheels and thus in the conveying direction of the internal gear pump. The bevel can, but does not have to be, a flat surface. In its wide range, the wedge gap communicates with the suction area of the internal gear pump, so that the

Gears of the internal gear pump, if they rotate during operation of the internal gear pump, due to the drag effect liquid from the suction in the narrowing wedge gap and thus between the faces of the rotating gears and the inner sides of the axial disc / n promote. The wedge gap between the inclined surface of the axial disc / s and the gears of the internal gear pump forms a lubricant supply and may be realized alone or together with one or more lubricant channels in the axial disc (s). Short description of the drawing

The invention will be explained in more detail with reference to an embodiment shown in the drawing. FIG. 1 is an end view of an internal gear pump according to the invention;

Figure 2 is a view of an inner side of an axial disc of the internal gear pump of Figure 1; and FIG. 3 is a sectional view of a ring gear and the axial disks of the internal gear pump of FIG. 1.

DESCRIPTION OF THE EMBODIMENT OF THE INVENTION The internal gear pump 1 according to the invention shown in FIG

Ring gear 2, so an internal gear, and an external gear, here as a pinion. 3 is called on. The pinion 3 is rotatably mounted on a shaft 4. The ring gear 2 is rotatably mounted in a bearing ring 5, which is pressed into a pump housing, not shown. The pinion 3 and the ring gear 2 have a same width and parallel axes, they are arranged eccentrically to each other so that the pinion 3 and the ring gear 2 mesh with each other on a peripheral portion. By rotation of the shaft 4, the pinion 3 is driven to rotate and in turn drives the ring gear 2 rotationally, a direction of rotation is indicated by arrow 6. Together, the pinion 3 and the ring gear 2 are also referred to as gears 2, 3 of the internal gear pump 1.

On a peripheral portion in which the pinion gear 3 and the ring gear 2 do not mesh with each other, they define a crescent-shaped pumping space 7 between them, the ring gear 2 defining the pumping space 7 on the outside and the pinion 3 on the inside of the pumping space 7. The pump chamber 7 extends from a suction region 8 to a pressure region 9. A bore 10 opens into the suction region 8 as an inlet 10. A sickle-shaped body, here referred to as a sickle 11, which separates the suction region 8 from the pressure region 9, is arranged in the pump chamber 7 , The sickle 11 is as wide as the pinion 3 and the ring gear 2, on its cylindrical outer surface slide tooth heads of the ring gear 2 and on its hollow cylindrical inner surface tooth heads of the pinion 3 along. The sickle 1 1 closes

Liquid volumes in interdental spaces of the ring gear 2 and the pinion 3, which are promoted by the rotating pinion 3 and the rotating ring gear 2 during operation of the internal gear pump 1 from the suction side 8 to the pressure side 9. In the illustrated embodiment of the invention, the sickle 11 is a two-part body, the two parts are hinged together and are pressed by an adjacent leg spring 12 outwardly against the tooth tips of the ring gear 2 and inwardly against the tooth tips of the pinion 3. In addition, communicates a gap 13 between the inner and the outer part of the sickle 11 with the pressure region 9, so that the two parts of the sickle 1 1 outwardly against the tooth tips of the ring gear 2 and inwardly against the

Tooth tips of the pinion 3 are pressed. A pin 14 holds the sickle 11, which is supported in the circumferential direction on a stop pin 15 against the pressurization of the pressure side 9.

On both sides of the pinion 3 and the ring gear 2 axial discs 16 are arranged, one of which is shown in Figure 2. The axial discs 16 are fixed arranged in the pump housing, not shown, they do not rotate with the pinion 3 and the ring gear 2 with. The axial discs 16 abut with their inner sides on end faces of the pinion 3 and the ring gear 2. The axial discs 16 limit the pump chamber 7 laterally. Inner and outer sides of the axial slide 16 are end faces of the axial disks 16.

In the illustrated embodiment of the invention, the axial discs 16 are approximately circular segment-shaped, so limited by a circular arc and a chord, the axial discs 16 are larger than a semicircle. An extending in the direction of a chord edge 17 of the axial discs 16 ends with a notch 18 in the form of an oblique step. The shape of the axial discs 16 is not mandatory for the invention. The axial discs 16 have a through hole 19 for the shaft 4 of the internal gear pump 1 and a bore 20 for the stop pin 15 for the sickle 11.

So that the axial discs 16 seal to the pinion 3 and the ring gear 2, their outer sides are pressurized (Figure 2 shows the inside of an axial disc 16!). For pressurizing, the outer sides of the axial disks 16 have a so-called pressure field 21, which is indicated by a dashed line in FIG. 2 and can be seen in the sectional representation of FIG. The pressure field 21 is a recess in the outside of the axial disc 16 with, for example, a sickle shape. The pressure field 21 can also be formed in the pump housing, not shown. In the exemplary embodiment, the pressure field 21 communicates with the pressure region 9 of the pump chamber 7 through an approximately quarter-circular slot 22, which passes through the axial disk 16 transversely.

Along the edge 17 of the axial disks 16, which extends in the chordwise direction, the axial disks 16 of the internal gear pump 1 according to the invention have an oblique surface 23 on the insides of the axial disks 16. The oblique surface 23 extends on a strip parallel to the edge 17 of the axial discs 16. The inclined surfaces 23 on the inner sides of the axial discs 16 which abut the pinion 3 and the ring gear 2, define wedge gaps 24 between them and the end faces of the pinion 3 and the ring gear 2. The wedge gaps 24 can be seen in FIG. 3, which show an axial section of the ring gear 2 and an offset parallel to it at the level of the teeth of the ring gear 2

Section of the axial discs 16 shows. All other parts are for clarity omitted in Figure 3. The wedge gaps 24 between the axial discs 16 and the ring gear 2 are also present between the axial discs 16 and the pinion 3. The wedge gaps 24 narrow in the direction of rotation 6 of the ring gear 2 and the pinion 3. For the suction region 8, which is indicated by dashed lines in Figure 3, the wedge gaps 24 are open. In FIG. 3, the bore forming the inlet 10 of the internal gear pump 1 and opening into the suction region 8 of the pump chamber 7 is also indicated by dashed lines.

During operation of the internal gear pump 1, the wedge gaps 24 effect or improve hydrodynamic lubrication between the axial disks 16 and the pinion 3 and the ring gear 2: by their rotation, the pinion 3 and the ring gear 2 promote liquid adhering to their end faces from the suction region 8 as a lubricating film between them and the axial discs 16. The wedge gaps 24, which form the inclined surfaces 23 of the axial discs 16 between themselves and the pinion 3 and the ring gear 2, improve the formation of the lubricating film. The structure of the lubricating film between the axial discs 16, which are pressed by pressurizing from the outside against the pinion 3 and the ring gear 2, is similar to the structure of a lubricating film of a hydrodynamic thrust bearing. The lubricating film reduces friction and wear.

Viewed radially at the level of the teeth of the pinion 3 and the ring gear 2 and seen in the circumferential direction at the height of the bore 20 for the stop pin 15, the axial discs 16 of the internal gear pump according to the invention 1 bores 25, 26, the axial discs 16 of the internal gear pump according to the invention. 1 transversely prevail. In other words, the bores 25, 26 are arranged near the edge 17 of the axial discs 16, on which the pinion 3 and the ring gear 2 move in a rotary drive between the axial discs 16 in. As indicated by dashed lines in Figure 3, communicate the bores 25, 26 in the axial discs 16 through channels 27 in side walls of the internal gear pump 1 with the suction region 8 of the pump chamber 7 and with the inlet 10 of the internal gear pump 1. Through the holes 25, 26 passes liquid from the inlet 10 and the suction region 8 of the internal gear pump 1 on the end faces of the pinion 3 and the ring gear 2 and is promoted in a rotary drive of the pinion 3 and the ring gear 2 between the externally applied axial discs 16 and the pinion 3 and the ring gear 2. By the bores 25, 26 are thus likewise hydrodynamic lubrication of the pinion 3 and the ring gear 2 between the axial discs 16. The bores 25, 26 may be provided in addition to or instead of the inclined surface 23. To supply liquid as a lubricating film elsewhere between the axial discs 16 and the pinion 3 and the ring gear 2, it is conceivable that the holes

25, 26 or provide additional holes at other locations of the axial discs 16 (not shown).

The wedge gaps 24, like the bores 25, 26, form a lubricant supply between the axial disks 16 and the pinion 3 and the ring gear 2, wherein the bores 25, 26 in the axial disks 16 can also be more generally understood as lubricant channels.

Claims

claims

1. internal gear pump, with a ring gear (2) and a pinion (3), which is arranged eccentrically in the ring gear (2) and on a peripheral portion with the ring gear (2) meshes, wherein the ring gear (2) and the pinion (3) a pump space (7) defining between them outwardly and inwardly, which extends in the circumferential direction of a suction region (8) to a pressure region (9) outside of the peripheral portion in which the ring gear (2) and the pinion (3) mesh , and with at least one axial disc (16), which is arranged on an end face of the ring gear (2) and the pinion (3) which abuts against the end faces of the ring gear (2) and the pinion (3) and on its the ring gear ( 2) and the pinion (3) facing away from the outside is pressurized, and the pump chamber (7) bounded on one side, characterized in that the internal gear pump (1) a lubricant supply from the suction area between the at least one axial disc (16) and the ring gear ( 2) and / or the pinion (3).

2. Internal gear pump according to claim 1, characterized in that the lubricant supply has a lubricant channel (25, 26) in the at least one axial disc (16) which communicates with the suction region (8) of the internal gear pump (1) and on the inside of the at least one Axial disc (16) at one end face of the ring gear (2) and / or the pinion (3) opens.

3. Internal gear pump according to claim 2, characterized in that the lubricant channel (25, 26) passes through the at least one axial disc (16) from the outside to the inside.

4. internal gear pump according to claim 1, characterized in that the at least one axial disc (16) has an inclined surface (23) on its the ring gear (2) and the pinion (3) facing inside, in the suction region (8) of the internal gear pump (1 ) has a distance from the ring gear (2) and / or the pinion (3) and in a conveying direction of the inner gear pump (1) the ring gear (2) and / or the pinion (3) approaches and a narrowing in the conveying direction wedge gap (24) between the at least one axial disc (16) and the ring gear (2) and / or the pinion (3 ), which communicates with the suction area (8) and forms the lubricant supply.