WO2013164111A2

WO2013164111A2 - Internal-gear pump

Info

Publication number: WO2013164111A2
Application number: PCT/EP2013/054596
Authority: WO
Inventors: Romuald FLAVIGNIE; Rene Schepp
Original assignee: Robert Bosch Gmbh
Priority date: 2012-05-02
Filing date: 2013-03-07
Publication date: 2013-11-07
Also published as: CN104334880A; CN104334880B; WO2013164111A3; DE102012207259A1; JP6031592B2; JP2015514915A; KR101984483B1; KR20150004364A

Abstract

The invention relates to an internal-gear pump (1) having a leg spring as separator (7) between a suction side (8) and a pressure side (9). The invention proposes to configure middle regions (a, b) of legs (13, 14) of the separator (7) to be thicker than free ends and transitions (c, d) to a yoke (15) of the separator (7), in order that the legs (13, 14) as far as their free ends bear with high prestress against teeth tips of gearwheels (2, 3) of the internal-gear pump (1). In order to reduce mechanical stresses in the region of the yoke (15) of the separator (7), great curvatures are provided at the transitions (c, d) from the legs (13, 14) to the yoke (15).

Description

description

title

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

The published patent application DE 10 2007 049 704 A1 discloses an internal gear pump for hydraulic vehicle brake systems which has an internally toothed ring gear and an externally toothed pinion which is arranged eccentrically in the ring gear in such a way that it meshes with the ring gear in a circumferential section. In the ring gear is an internally toothed gear and the pinion gear to an externally toothed gear, the designation as a ring gear and a pinion has been selected for differentiation. Together, the ring gear and the pinion may also be referred to as gears of the internal gear pump. Outside the peripheral portion in which the pinion meshes with the ring gear, the pinion and the ring gear interpose a sickle-shaped pumping space therebetween in which a separator is disposed separating a suction side from a pressure side of the internal gear pump in the pump space. The separator of the known internal gear pump is a leg spring, which is the same width as the gears of the internal gear pump. An inner and an outer leg of the separator are curved according to the gears of the internal gear pump, tooth tips of teeth of the pinion abut the inner leg and tooth tips of teeth of the ring gear on the outer leg of the separator designed as a leg spring, so that liquid is enclosed in interdental spaces of the gears and is conveyed by the rotary drive of the gears in a conventional manner from the suction side to the pressure side. The two legs of the separator are integrally and resiliently connected by a yoke. To designate: As inner sides of the legs of the separator the mutually zugawandten sides of the legs are called. The outer sides of the legs abut against the tooth tips of the gears.

Disclosure of the invention

The separator of the internal gear pump according to the invention with the features of claim 1 is also designed as a leg spring with legs of teeth of the pinion gear and the ring gear adjacent legs. In their middle regions, the legs are thicker than at their free ends and at junctions to the yoke of the separator. From the thicker middle area, the thighs taper to the free ends and to the junctions to the yoke. The middle portions of the legs of the separator extend longitudinally of the legs, d. H. in the circumferential direction of the internal gear pump and its gears. The middle portions of the legs terminate at a distance from the free ends of the legs and at a distance from the transitions from the yoke to the legs. The central areas need not be in the longitudinal centers of the legs, they may be closer to the free ends or the junctions to the yoke. Due to the thickness distribution of the legs of the separator, a spring stiffness of the legs changes over their length.

The invention improves an investment of the legs of the separator formed as a leg spring on the tooth tips of the gears of the internal gear pump and thus a seal between the interdental spaces. The thighs of the

Separator of the internal gear pump according to the invention are better at the tooth tips of the gears over their length. While in the prior art legs of a separator are pressed due to a spring force of the separator substantially close to the yoke against the tooth tips of the teeth of the gears of an internal gear pump presses in the internal gear pump according to the invention, the spring force of the separator, the legs even in the region of their free ends against the teeth heads , In a favorable case, the legs are pressed evenly over their entire length against the tooth heads. What is meant is a pressing force of the legs of the separator against the tooth tips of the gears of the internal gear pump due to the spring force of the as

Leg spring trained separator on its own or under Considering a hydraulic internal pressure between the legs during operation of the internal gear pump, which is constant over the length of the legs and as a result of a constant over the length of the leg force radially on the inner leg inwards and on the outer Schenkl outwards.

It is also possible a thickness distribution and shaping of the legs of the separator, through which increases the pressing force of the legs against the tooth tips of the gears of the internal gear pump in the direction of the free ends of the legs. The pressing force of the legs of the separator increases in this case in the direction of the pressure side of the internal gear pump and is thereby greater where a hydraulic pressure in the interdental spaces is greater, which counteracts the plant of the legs on the tooth tips. The sealing effect can be improved thereby.

The dependent claims have advantageous refinements and developments of the invention specified in claim 1 to the subject.

Subject matter of claim 7 is a curvature course on an outer and an inner or an outer and an inner surface of the separator in the region of the yoke and transitions from the yoke to the legs, which are integral with the yoke. At the junctions from the yoke to the legs, the outsides of the separator are convex circular arc shaped, that is, the outer surfaces are convex cylindrical surfaces. Between the transitions to the legs, the outer surface of the yoke of the separator is concavely curved in a cylindrical shape. At the transition from the yoke to the inner leg, an inner surface of the separator is concavely cylindrically curved, with a radius of curvature greater than a radius of curvature outside at the transition from the yoke to the inner leg. It does not depend on exact cylinder shapes. This embodiment of the invention improves the yoke region and the transitions from the yoke to the legs of the separator with respect to acting in the separator mechanical stresses, mechanical stresses are better distributed and locally high voltages avoided or reduced mechanical stress peaks. The features of claim 7 may be realized in embodiments of the invention without the characterizing features of the main claim. Short description of the drawing

The invention will be explained in more detail with reference to an embodiment shown in the drawing. Show it:

Figure 1 is a side view of an internal gear pump according to the invention; and

Figure 2 shows a separator of the internal gear pump of Figure 1 according to the invention as a single part in a larger view.

The drawing is to be understood as a schematic and simplified representation for understanding and explaining the invention. Embodiment of the invention

The illustrated in Figure 1, according to the invention internal gear pump 1 has two gears 2, 3, namely an internally toothed ring gear 2 and an externally toothed gear, which is referred to here as pinion 3. The pinion 3 is eccentrically arranged in the ring gear 2, the two gears 2, 3 have mutually parallel axes and mesh with each other. The ring gear 2 is rotatably mounted slidably in a bearing ring 4, the pinion 3 is rotatably mounted on a pump shaft 5. For clarity, a housing of the internal gear pump 1 is not shown. For operation of the internal gear pump 1, the pump shaft 5 is driven in rotation, with it rotates on the pump shaft 5 non-rotatable pinion 3 and drives the intermeshing ring gear 2 rotationally. One direction of rotation is indicated by the arrows P.

The gears 2, 3 define a sickle-shaped pump chamber 6 in a peripheral portion in which they do not mesh with each other, between them. in the

Pump chamber 6 is a sickle-shaped separator 7 is arranged, which can also be understood as a semi-or semi-sickle-shaped and is often referred to as a sickle or sickle body due to its shape. The separator 7 separates a suction side 8 from a pressure side 9 in the pump chamber 6 of the internal gear pump first Into the suction side 8 opens an inlet bore 10, from the pressure side 9 performs an outlet hole 1 1. Toothed heads of the gears 2, 3 of the internal gear pump 1 lie on an outer or inner side of the separator 7 and slide in a rotary drive of the gears 2, 3 along the outside or inside of the separator 7 along. The separator 7 is the same width as the gears 2, 3, both of which have the same width. The separator 7 includes liquid volumes in interdental spaces of the gears 2, 3, so that a rotary drive of the gears 2, 3 causes a promotion of liquid from the suction side 8 to the pressure side 9. At a suction end, the separator 7 is supported on a bolt which passes through the pump chamber 6 transversely and is referred to here as an abutment 12.

In the exemplary embodiment, the sickle-shaped separator 7 is a leg spring. The leg spring is a U-shaped leaf spring with two arcuately curved in the same direction legs 13, 14, where as already said the tooth tips of the teeth of the gears 2, 3 are present. The tooth tips abut on the outer sides of the legs 13, 14, the outer side of an inner leg 13 of the separator 7 is directed inwardly with respect to the internal gear pump 1 and forms an inner side of the separator 7. Inner sides of the legs 13, 14 of the separator 7 are facing each other. A yoke 15 connects the two legs 13, 14 and abuts the abutment 12. The separator 7 forming leg spring is open at its pressure-side end, so that an inner space 16 between the legs 13, 14 of the leg spring is acted upon by the pressure prevailing on the pressure side 9, the legs 13, 14 apart, d. H. the outer leg 14 is acted outwardly against the tooth tips of the teeth of the ring gear 2 and the inner leg 13 inwardly against the tooth tips of the teeth of the pinion 3. As a result, the legs 13, 14 of the

Leg spring, which forms the separator 7 of the internal gear pump 1, even in changing pressure conditions always sealingly against the tooth tips of the teeth of the gears 2, 3 of the internal gear pump 1 at. In addition, the legs 13, 14 are due to a spring force of the separator formed as a leg spring 7 with a bias to the tooth tips of the teeth of the gears 2, 3, so for example, in unpressurized internal gear pump. 1

The legs of the separator 7 have a changing over its length thickness and thus over the length changing spring stiffness. Shape and thickness profile of the separator 7 is clearly visible in Figure 2, which is the separator

7 as an item shows. In a central region a, the inner leg 13 is diagonal. The middle region a terminates at a distance from the free end and at a distance from the transition c from the yoke 15 to the inner leg 13. In the exemplary embodiment, the thicker central region a of the inner leg 5 is not symmetrical to a longitudinal center of the inner leg 13 but closer to the free end. However, this is not mandatory for the invention. From the central region a, the inner leg 13 tapers to both the free end and the transition c to the yoke 15. Due to the greater thickness, the inner leg 13 of the separator 7 in its central region a a greater Fel o dersteifigkeit on. In the exemplary embodiment, the thickness and thus the spring stiffness in the central region a of the inner leg a is almost constant, which, however, is not mandatory for the invention. The central region a of the inner leg 13 can be considered as plateau-shaped. The outer leg 14 facing the inner side of the inner leg 13 curves at 15 both ends of the central region a first convex and then concave both to the free end of the inner leg 13 and in the direction of the transition c to the yoke 15 of the separator. 7

The outer leg 14 also has a central region b, in which the

20 outer leg 14 thicker and thus its spring stiffness is higher than at its free end and a transition d to the yoke 15 out. However, the outer leg 14 has no constant thickness in its middle region b, but its thickness steadily increases from the transition d to the yoke 15 up to the middle region b and then again as far as the free end. The thickest part of the

25 outer leg 14 may be located approximately in a longitudinal center of the leg 14, in the embodiment, the thickest point is closer to the free end than the yoke 15. The thickness distribution of the outer leg 14 is achieved by a stronger convex curvature of its outer side than the concave curvature of his Inside. The outside is due to the attachment to the Zahnköp-

30 fen of the ring gear 2 circular, the outer surface so cylindrical. The inner side of the outer leg 14 has a weaker curvature in the middle region b than the free end and the yoke 15. The concave curvature of the inside of the outer Schenklels 14 is weaker than the convex curvature of its outer side. The greater thickness in the middle region of the leg 14

35 is achieved by the shape and position of the inner side in relation to the circular outer side, it is also possible with a circular inner side, preferably a radius of curvature of the inside not smaller than a radius of curvature of the outside.

The thickest points of the inner and the outer leg 13, 14 are in Ausführungsbeipiel the thickest points of the separator. 7

The shapes, in particular the thickness distributions of the legs 13, 14 of the separator 7 with the thicker central regions a, b cause the legs 13, 14 over its entire length with almost constant bias voltage applied to the tooth tips of the teeth of the gears 2, 3. By the thick central regions a, b is achieved that the legs 13, 14 even near their free, the yoke 15 far ends still with a comparatively high bias to the tooth tips of the teeth of the gears 2, 3, d. H. Also on the pressure side 9, where a pressure in the interdental spaces of the gears 2, 3 is high, the legs 13, 14 of the separator 7 with bias to the tooth tips and include a hydraulic fluid in the interdental spaces.

At the transitions c, d from the yoke 15 to the legs 13, 14, the separating piece 7 on the outside is circular arc-shaped convex and arcuately concave curved between the transitions c, d. Outer surfaces of the separator 7 are at the transitions c, d from the yoke to the legs 13, 14 thus convex cylindrical surfaces, between the transitions c, d, the outer surface of the yoke 15 is a concave cylindrical surface. On the inside of the separator 7, the transition c from the yoke 15 to the inner leg 13 is concave circular arc, the inner surface is at the transition c from the yoke 15 to the inner leg 13 so a concave cylindrical surface. Their radius is greater than radii on the outer sides of the transitions c, d from the yoke 15 to the legs 13, 14. The radius on the inside of the transition c from the yoke 15 to the inner leg 13 is also greater than one half of a largest distance between the both

Legs 13, 14. By this shape of the separator 7 in the region of the yoke 15 and the transitions c, d from the yoke 15 to the legs 13, 14 are mechanical stresses in the region of the yoke 15 and the overflow c, d from the yoke 15 to the Thighs 13, 14 reduced and evenly or at least more evenly distributed. The mechanical stresses are caused by the bias with which the legs 13, 14 on the tooth tips of the teeth of the tooth wheels 2, 3 abut the internal gear pump 1, and caused by the pressurization by the hydraulic fluid from the outside and from the inside. In the yoke 15 and the transitions c, d to the legs 13, 14, the mechanical stresses in the separator 7 are highest, which is why there geomet- rie of the separator 7, which distributes the mechanical stresses as evenly as possible and avoids high local voltages important or anyway is advantageous.

The internal gear pump 1 is provided as a hydraulic pump for a hydraulic vehicle brake system, in particular as a so-called return pump for a

Slip control of a hydraulic vehicle brake system and / or pressure build-up in a hydraulic power-operated vehicle brake system.

Claims

claims

1 . Internal gear pump, with an internally toothed ring gear (2) and with an externally toothed pinion (3), which is arranged eccentrically in the ring gear (2) and meshes in a peripheral portion with the ring gear (2), wherein the ring gear (2) and the pinion (3 ) outside the peripheral portion, in which the pinion (3) meshes with the ring gear (2), a sickle-shaped pump chamber (6) between them, in which a separator (7) is arranged, which a suction side (8) from a pressure side ( 9) in the pump chamber (6) separates, wherein the separator (7) is designed as a leg spring having a curved inner leg (13) which abuts teeth of teeth of the pinion (3), a curved outer leg (14) on tooth tips of teeth of the ring gear (2) is applied, and a the two legs (13, 14) connecting the yoke (15), characterized in that the legs (13, 14) in the middle regions (a, b) are thicker and to their free ends and to transitions (c, d) of d the legs (13, 14) taper towards the yoke (15).

2. internal gear pump according to claim 1, characterized in that the separating piece (7) has a maximum thickness in the central regions (a, b) of the legs (13, 14).

3. internal gear pump according to claim 1, characterized in that the inner leg (13) of the separator (7) has an approximately constant thickness in its central region (a).

4. internal gear pump according to claim 1, characterized in that an inner side of the inner leg (13) of the separator (7) between the transition (c) from the yoke (15) to the inner leg (13) to the central region of the inner leg (13) and from the free end to the central region (a) of the inner leg (13) is concavely curved. Internal gear pump according to claim 1, characterized in that a concave curvature of an inner side of the outer leg (14) of the separator (7) is at least as large and preferably larger than a convex cylindrical curvature of its outer side.

Internal gear pump according to claim 5, characterized in that the concave curvature of the inside of the outer leg (14) of the separator (7) in the central region (b) of the leg (14) is smaller and the free end and the transition (d) to the yoke (15) increases.

Internal gear pump according to claim 1, characterized in that the separator (7) at transitions (c, d) of the legs (13, 14) to the yoke (15) cylindrical convexly curved outer surfaces and therebetween a cylindrical concave curved outer surface and at the transition (c ) from the inner leg (13) to the yoke (15) has a cylindrical concave curved inner surface whose radius is greater than a radius of curvature of the outer surface at the transition (c) from the inner leg (13) to the yoke (15).

Internal gear pump according to claim 1, characterized in that an inner space (16) of the separating piece (7) between the inner leg (13) and the outer leg (14) with the pressure side (9) of the pump chamber (6) communicates.