EP0043899B1 - Annular gear pump - Google Patents

Annular gear pump Download PDF

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Publication number
EP0043899B1
EP0043899B1 EP81103438A EP81103438A EP0043899B1 EP 0043899 B1 EP0043899 B1 EP 0043899B1 EP 81103438 A EP81103438 A EP 81103438A EP 81103438 A EP81103438 A EP 81103438A EP 0043899 B1 EP0043899 B1 EP 0043899B1
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EP
European Patent Office
Prior art keywords
teeth
annular gear
wheel
tooth
ring gear
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Expired
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EP81103438A
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German (de)
French (fr)
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EP0043899A1 (en
Inventor
Siegfried A. Dipl.-Ing. Eisenmann
Original Assignee
Siegfried A. Dipl.-Ing. Eisenmann
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Priority to DE3026222A priority Critical patent/DE3026222C2/de
Priority to DE3026222 priority
Application filed by Siegfried A. Dipl.-Ing. Eisenmann filed Critical Siegfried A. Dipl.-Ing. Eisenmann
Publication of EP0043899A1 publication Critical patent/EP0043899A1/en
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04CROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2/00Rotary-piston machines or pumps
    • F04C2/08Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C2/082Details specially related to intermeshing engagement type machines or pumps
    • F04C2/084Toothed wheels

Description

  • The invention relates to a gerotor pump with a housing, an internally toothed ring gear with 8 to 16 teeth, which is rotatably mounted in the housing, and a pinion which meshes with the ring gear and is supported by a drive shaft and has one tooth less than the ring gear, with the seal between the suction chamber and the pressure chamber opposite the deepest tooth engagement by sliding the tooth tips of the pinion on the ring gear teeth and the deepest tooth engagement by contacting the driving tooth flanks of the pinion on the ring gear teeth, furthermore the tooth heads of the pinion in the tooth gaps of the ring gear go free and the theoretical tooth shape of the pinion is determined by rolling the pinion rolling circle on the ring gear rolling circle. Such gerotor pumps have been known for a long time. Reference is made, for example, to Lueger, Lexikon der Technik, Deutsche Verlagsanstalt, Stuttgart, Vol. 7, 1965, p. 218, where such pumps are described under the name "Eaton pump". These known pumps are of simple construction. The teeth of the ring gear are usually designed in the form of circular segments; i.e. the entire tooth contour is determined by a single circular arc. Instead of the circular arc contour, another curve, such as a cycloid, can also be selected, as in the present invention. A major problem with these known Eaton gears now lies in the fact that each tooth of the ring gear is in constant contact with one tooth of the pinion. This is due to the fact that the pinion has only one tooth less than the ring gear. The fact that all teeth are in constant contact brings significant problems not only in production, but also in operation. On the one hand, the production must be very precise. If wear occurs in the course of operation, the seal between the suction chamber and the pressure chamber of the pump, especially in relation to the point of deepest meshing, becomes inadequate and the efficiency of the pump drops considerably. The pump is also very susceptible to wear, since during operation there is very strong specific sliding between the parts of pinion teeth and ring gear teeth that are in contact with one another. This is primarily due to the fact that the areas of the tooth surfaces of the ring gear corresponding to the tooth flanks of a normal gear are relatively strongly inclined. In addition, Hersian pressure is particularly high on the parts of the pinion teeth that primarily transmit torque on the ring gear teeth, namely on their relatively sharply curved edges between tooth flanks and tooth heads, which in turn promotes wear.
  • Furthermore, the fluctuation of the instantaneous delivery volume over the angle of rotation and thus the delivery pulsation of these pumps is very large.
  • Another problem with the Eaton pump is that the individual delivery spaces limited in the radial direction by the ring gear and pinion constantly change their volume, since they are separated from one another by the multiple tooth meshing. This leads to a division of the work spaces into individual chambers, which is not desirable, even if they are connected to one another by side pockets in the housing.
  • Finally, the multiple tooth engagement of the Eaton pump has the disadvantage that, depending on the manufacturing tolerance of the tooth flank shape, both on the ring gear and on the pinion of the real tooth engagement under Herz's pressure for torque transmission from the pinion to the ring gear in the circumferential direction is often far away from the point of deepest meshing. Because of the then changed angular position of the pressure point between the tooth flanks of the pinion and ring gear, a tooth force component is then created on the ring gear which tends to increase the center distance of the two wheels. The consequence of this is that the seal between the teeth deteriorates compared to the point of deepest tooth engagement, and because the tooth forces then increase, the higher the delivery pressure, the more so.
  • All of this has meant that the Eaton pump, despite its initially impressively simple design, only found limited use in practice for relatively few cases.
  • The disadvantages of the Eaton pump are eliminated in known gear pumps with a difference in the number of teeth of more than 1, in which the teeth are not in engagement in the area opposite to the point of deepest tooth meshing, in that in the area of the mentioned location a generally has a moon or is arranged in the form of a solid filling piece, on the convex surface of which the tooth heads of the ring gear slide, while on the concave surface of the filling piece the tooth heads of the pinion slide along. Here you are much freer with regard to the tooth shape, so that the meshing conditions can be chosen more favorably. However, this type of pump is much more complex than the Eaton pump because of the expense for the filler, which also includes the exact positioning and shape of the filler.
  • The invention has set itself the task of further developing the Eaton pump, as outlined in the preamble of claim 1, in such a way that the tooth surfaces of the pinion and ring gear, which are in meshing engagement with one another, slide less on one another and lie against one another over a large area, as a result of which the Herz's Pressure is reduced, that the delivery chambers between each pair of teeth of pinion and ring gear are large, that the essential disadvantage of the continuous volume change of the delivery chambers mentioned is at least largely eliminated and that the toothing voltage is less sensitive to warping compared to the known Eaton gearing. Furthermore, the invention is intended to achieve better smoothness and to reduce the risk of oil film stripping. Finally, a non-invasive area is to be created which avoids the drive engagement intermingling with the sealing engagement lying opposite it.
  • In solving this problem, the invention encompasses the basic idea that the engagement ratios and other relationships set out above for the Eaton pump are substantially improved by dividing the ring gear tooth into two parts, namely a driving area and, at the point, the deepest tooth meshing area and another area of the tooth head, which only has the task of sealing at the point opposite the deepest tooth engagement. The first step in accordance with the invention is that two Eaton ring gear teeth with curved tooth contours and halved by half a tooth pitch in the circumferential direction compared to the desired number of teeth are superimposed on one another and only those parts of the teeth that are left of the teeth of both are left standing Gears are covered. In this way, each tooth contour arc of the original Eaton gears spanned two of the remaining teeth, which now have a triangular shape with convexly curved flanks. The tooth arch thus defines the two tooth flanks facing away from each other of two adjacent teeth. In this way, only the relatively steep areas of the original Eaton tooth profile close to the tooth root, which have favorable engagement conditions, remain for the tooth engagement. However, the tooth profile created in this way does not yet permit a permanent seal at the point opposite the deepest tooth engagement. To make this possible, the toothing is now superimposed on a third Eaton toothing, the pitch of which is equal to half the pitch of the original full Eaton toothing. The center of the tooth arch of this Eaton toothing coincides with the center of the “triangular teeth” and cuts off the triangular tip. As a rule, this cutting must take place at such a height that the resulting tooth tip surface is wide enough in the circumferential direction to ensure that, compared to the point of deepest tooth engagement, the leading of two successive ring gear teeth comes out of engagement with the pinion at the earliest when the following ring gear tooth is already in engagement with the pinion.
  • In this way, in the case of the ring gear, the flat, curved tooth head profile of the Eaton toothing, which is very advantageous for the seal at the point of deepest tooth engagement, is also present in the new toothing according to the invention. Because the tooth tips are cut off, the theoretical degree of coverage falls below the value one. In practice, however, this has no disruptive influence on the teeth according to the invention, as long as the ring gear has no less than eight teeth.
  • Another essential criterion of the toothing according to the invention is that the pitch circle of the ring gear runs in the area of the “theoretical” tooth root of the ring gear and accordingly the pitch circle of the pinion runs in the area of the “theoretical” tooth tip of the pinion. However, the requirement regarding the pitch circles does not have to be met exactly, but it should at least be met approximately. At least the pitch circle of the ring gear should run outside the circle around the center of the ring gear through the lower third of the tooth height of the ring gear. With larger numbers of teeth, the pitch circle of the ring gear can also lie somewhat outside the root circle of the ring gear. This is especially true for teeth over ten. Similarly, depending on where exactly the pitch circle of the ring gear is located, the pitch circle of the pinion must also be shifted inwards or outwards by the appropriate amount. This inward shifting of the pitch circles may be necessary if the number of teeth on the ring gear becomes small, e.g. with eight teeth.
  • The condition that the pitch circles should be approximately equal to the root circle of the ring gear or the tip circle of the pinion ensures that the teeth no longer come into contact with one another in the areas between the point of deepest tooth engagement and the opposite point. The problem of changing delivery chambers between two pairs of teeth is thus eliminated. This also eliminates the problem of unwanted interdental interventions. According to the above, the invention is characterized in that in a gerotor pump of the type outlined at the outset, the teeth of the ring gear have an approximate trapezoidal shape with convexly curved flanks and heads, and that the pitch circle of the ring gear runs outside the circle around the ring gear center through the lower third of the tooth height of the ring gear .
  • When we speak of a theoretical tooth root circle, a theoretical tooth tip circle or other “theoretical” parameters of the gearing, the attribute “theoretical” is intended to express that these are not necessarily the corresponding actual parameters, but rather the parameters such as they arise with an ideal, completely free of play and error-free toothing without rounded edges.
  • Although the tooth shape is preferably completely symmetrical in the invention, as is generally customary, an asymmetrical tooth shape can also be used in principle. This applies in particular if the pump is only designed for a certain direction of rotation. In this case, then the two Eaton tooth contours, which define the two tooth flanks of the teeth, are not the same.
  • The construction of a toothing according to the invention is then relatively simple. Once the diameter and the desired number of teeth of the ring gear have been determined, the requirement for “number of teeth difference = one” results in the tooth height. Now the theoretical tooth contour can be designed with the help of appropriate circular arcs or curved arches. Of course - as with any Eaton toothing - care must be taken that the resulting tooth gap is wide enough. From the theoretical ring gear profile created in this way, the theoretical pinion profile can be determined graphically - today mostly mathematically.
  • Now only the tooth gaps have to be deepened slightly, so that the tooth heads are clear and that no particularly precise machining is required at the base of the tooth gaps.
  • The tooth shape is preferably determined for the ring gear in such a way that the extent of the ring gear teeth and the extent of the ring gear tooth gaps in the circumferential direction on the circle through half the height of the ring gear teeth is approximately the same. This condition has the further consequence that the theoretical tooth tip width of the ring gear teeth is approximately equal to two thirds of the theoretical width of the tooth gap on the other foot. Such a design leads not only to a relatively large delivery volume measured by the pump diameter, but also to steep tooth flanks.
  • The tooth tip width (without the rounding to be explained later) of the ring gear is preferably 0.65 times to 0.7 times and the width of the tooth gap at the theoretical root circle of the ring gear (again without the rounding to be explained later) is 1.05- up to 1.1 times the theoretical tooth height of the ring gear. A design has proven itself in which the tooth tip radius of curvature of the ring gear is approximately 2 to 2.4 times, better 2.2 to 2.3 times the theoretical tooth height of the ring gear. The construction is also particularly favorable if the tooth flank radius of curvature of the ring gear is approximately 3.3 to 3.7 times, better 3.4 to 3.6 times the theoretical tooth height of the ring gear. The radius of curvature of the tooth flank in this sense is the same as the radius of curvature of the original Eaton toothing by superimposing and displacing it by half a division of this original toothing.
  • The construction becomes particularly simple if the tooth tip curvature of the ring gear is a circular arc, the center of which lies on the radius line of the ring gear through the center of the tooth outside the tooth root circle and the tooth flanks of the ring gear run along circular arcs, the center points of which lie outside the tooth root circle. Instead of circular arcs, as explained above, other curves with a not exactly constant radius can occur here. However, the circular arcs have the advantage of being easy to grasp theoretically because of their constant radius.
  • In accordance with the basic explanation of the invention given at the outset, the tooth flanks of two adjacent teeth that face away from one another preferably lie on a common circular arc. However, this condition is not essential, for example, two circular arcs with the same radius but different center points can be provided, which intersect on the line through the center of the ring gear and the center of the tooth gap between the two adjacent teeth.
  • The construction is significantly simplified if the edges between the tooth flanks and the tooth tips of the ring gear are each rounded off along an arc that continuously merges into both the arc defining the tooth flank and the arc defining the tooth tip and has a radius that in the Of the order of a third of the theoretical tooth height of the ring gear. A measure of 0.3 times to 0.33 times the theoretical tooth height of the ring gear has proven itself here. If you make this radius too small, you will be forced to cut it out relatively deeply to avoid notching effects on the tooth root pinion. If you make the radius too large, the area opposite the point of deepest meshing, in which the tooth tips of the ring gear and pinion lie perfectly against one another, becomes too small, and there is a risk of a pulsating compensation between the suction chamber and the pressure chamber. When designing the pinion from the gear shape of the ring gear, the rounded edges must also be taken into account.
  • In practice, the number of teeth of a gerotor pump according to the invention is limited by the requirement for a high pump output and thus the largest possible teeth. Accordingly, the ring gear preferably has 9 to 15 teeth, more preferably 11 to 13 teeth. A particularly favorable range is 10 to 12 teeth of the ring gear. Currently a number of 11 teeth on the ring gear is considered to be optimal in order to ensure a maximum delivery capacity of the pump for a given diameter.
  • The preferred embodiment of the invention is described below with reference to the drawings as an explanatory example.
    • Fig. 1 shows schematically the view of a ring gear of an Eaton pump, which is assumed in the construction of a pump according to the invention;
    • Fig. 2 shows schematically the construction of the tooth shape of the ring gear according to the invention;
    • Fig. 3 shows in the same view as Figure 1, the impeller of the pump according to the invention.
    • 4 shows, on a greatly enlarged scale, half of the area of deepest tooth engagement and shows the essential parameters of the preferred toothing shown.
    • Fig. 5 shows a gerotor pump according to the invention in a highly schematic section, which corresponds to the section line V-V in Fig. 3.
  • The pump is briefly explained below with reference to FIGS. 3 and 5.
  • 5, the pump has a housing which has a first left end plate 18 and a right end plate 19. An annular housing middle part 20 extends between the two end plates. The three housing parts define between them a flat cylindrical cavity in which the ring gear 10 is slidably mounted with its outer peripheral surface on the inner peripheral surface of the housing part 20. The pinion shaft 22 carrying the pinion 12 extends through a central bore of the right housing end part 20 and, as symbolically indicated by a wedge 23, is connected to the pinion 12 in a rotationally fixed manner. In FIG. 3 as well as in FIG. 5, the toothing of the pinion and ring gear are fully engaged, while below the tooth heads of the pinion and ring gear slide on each other.
  • The outlet opening 16 extends in the right housing end part 19, while the inlet opening 15 lies in the part of the housing end part 19 lying in front of the drawing plane in FIG. 5. As can be seen in FIG. 5, a connection channel runs from the drain or extension opening 16 through a connecting piece 24.
  • The three parts 18, 19 and 20 forming the housing are clamped together by screw bolts 25 distributed uniformly over the circumference.
  • 5, the axis of rotation MR of the pinion 12 and the axis of rotation M H of the ring gear 10 are also shown.
  • After the invention deals with the formation of the toothing of the pump, the general structure of the pump is not explained here any longer.
  • In the construction of the toothing according to the invention, it is assumed that the Eaton toothing contains the ring gear 1 of the Eaton pump according to FIG. 1. Here each tooth 2 has essentially the shape of a segment of a circle. The tooth base essentially coincides with the tooth root circle of the ring gear 1. Since the gearing shown in the example intended to comprise eleven teeth, has the ring gear 1, which is ultimately here only a theoretical tool for the invention construction 5 1/2 teeth 2. Draw it at the chipped tooth 2a of the internal gear tooth outline, as 1 in dashed lines, further, the displacement of the same tooth shape by half a division, which is the aim according to the invention, is already obtained.
  • However, this only applies to the construction of ring gears with an odd number of teeth. If a ring gear according to the invention is to be constructed with an even number of teeth, an Eaton ring gear with an entire number of teeth must of course be assumed.
  • Accordingly, in the explanation of the invention with reference to FIG. 2, it is generally assumed that the Eaton ring gear contour 1 shown hatched from the top left to the bottom right has an indefinite number of teeth. The center of this ring gear is shown at 3. The division T is shown only in the angular dimension. If you now limit the tooth outline of the ring gear contour 1 additionally by the same tooth contour 5, however, offset by half a tooth pitch, which is hatched in Fig. 2 from top right to bottom left, then only the equilateral triangles with convex flanks remain 6. teeth left, which are hatched both from top right to bottom left and from top left to bottom right. As a last step, a third ring gear contour 7 is superimposed on the tooth contour thus created, the division of which is equal to half the division t of the contours 1 and 5. The ring gear contour 7 is hatched in FIG. 2 from top to bottom. The greatest height of the teeth of the ring gear contour 7 is less than that of the ring gear contours 1 and 5, so that after overlaying all three ring gear contours, a tooth profile remains, which in FIG. 2 is from top left to bottom right, from top right to bottom left and vertically hatched from top to bottom. In this way, the ring gear toothing according to the invention is obtained in principle, which is shown in its entirety in FIG. 3 with reference to the ring gear 10, the teeth 11 of which have the shape obtained according to FIG. 2. The pinion 12 for the gearwheel set according to FIG. 3 is now obtained by rolling the root circle FH of the ring gear 10 onto the tip circle of the pinion 12. In this way, an enveloping figure is created which is exactly the same as the theoretical outline of the pinion 12.
  • 3 that the ring gear 10 is driven by the pinion 12 only in the area of the deepest tooth engagement. At the opposite point, only the tooth heads of at most 3 teeth of the ring gear or pinion slide on one another, while in the areas lying between (right and left in FIG. 3) the teeth of the pinion are completely free from those of the ring gear. In this way, the tooth flank construction can be designed optimally with regard to the gear mechanism, such as specific sliding, surface pressure and the like, on the one hand, but also with regard to the seal at the point of deepest tooth engagement, while the designer no longer has one for the formation of the tooth head certain flank construction is bound, but the tooth head curvature can also be chosen so that a practically pressure-free sliding of the tooth heads against each other is achieved compared to the point of deepest tooth engagement. In this area, the conveying spaces 14 closed here practically do not change between each tooth gap of the pinion and the ring gear more, so that a violent squeezing of the delivery liquid from the delivery rooms 14 practically no longer occurs. In the area of the suction opening 15 and in the area of the pressure opening 16, the conveying spaces between the teeth naturally change, but these spaces as a whole are practically constant over the angle of rotation, since they are not separated by tooth engagements.
  • The great length of the inlet and outlet openings, which the invention permits, is remarkable. Each opening extends over about a third of the circumference. This allows high speeds. For very high speeds of e.g. The kidney-shaped inlets and outlets can be extended even further than the point of deepest tooth engagement by 6000 rpm or more.
  • 4, the construction of a ring gear and a pinion for the gear set according to the invention is explained in more detail.
  • The ring gear is said to have eleven teeth. The pinion has ten teeth. Next, the diameter of the theoretical root circle FH of the ring gear 10 is selected, which, to give a numerical example, is assumed to be 66 mm. The root circle of the ring gear is also its pitch circle; the tip circle KR of the pinion 12 whose pitch circle. The theoretical tooth height H of the ring gear is 6 mm. Next, a pitch t of the ring gear is plotted from its center MH in the angular dimension and the bisector h of this pitch angle. Then you enter the desired dimension B for the theoretical tooth tip width around the bisector of the pitch angle on both sides on the tip circle KH of the ring gear 10, which is here, for example, about 4 mm, that is, it extends by 2 mm on both sides of the bisector h. In this way, the intersection points of the flank circles of the teeth with the ring gear head circle KH are first determined. Now a circular arc is formed around a point outside FH on the one boundary beam of the angular division, which is to be dimensioned such that the theoretical width of the tooth gap at the root circle of the ring gear is approximately 1.05 to 1.1 times H . To achieve this, the radius ro of this circle is selected with 20.66 mm in the exemplary embodiment shown. Now a circle outside the FH on line h is drawn through the intersection of h with KH, the radius of which is such that a relatively small curvature of the ring gear tooth head is measured at the tooth height. In the exemplary embodiment, this radius rm was selected to be around 13.8 mm, ie 2.3 H.
  • Finally, the edges between the tip circle with the radius rm and the flank circles with the radius ro are rounded off. For this purpose, a radius rk of 1.9 mm is selected in the exemplary embodiment, which continuously, ie with a common tangent, merges into the tooth flank arc and the tooth tip arc, as can be seen from FIG. 4. Now the pinion 12 is constructed as an inner envelope figure, which is created by rolling from FH to KR or vice versa. The resulting pinion tooth shape is shown in FIG. 4. As best seen in the top left in FIG. 4, the pinion tooth head ZKR, whose contour is formed by the tooth heads of the ring gear 10, by no means fills the tooth gap of the ring gear initially constructed, the base of which was formed by FH. Since this creates disturbing dead spaces, the gusset Z between the FH and the tooth tip curve ZKR, which is hatched in FIG. 4, is now filled in such a way that with the tooth gap of the ring gear located at the point of deepest tooth engagement, only a play of e.g. 0.04 to 0.05 H remains between the tooth tip curve ZKR of the pinion 12 and the tooth space base of the ring gear 10. Since, at the point of deepest tooth engagement due to the construction, the center of the tooth tip curve of the pinion 12 would just touch the bottom of the tooth gap of the ring gear 10, a small amount of material is removed at this center from the material of the ring gear, as also indicated at the top left in FIG. 4, so that the tooth base of the ring gear is now limited by the line HL obtained in this way.
  • Since the tooth gap base on the pinion 12 would lie against the tooth head of the ring gear due to the construction of the pinion outline at the point of deepest tooth engagement, i.e. at X in FIG. 4, a small amount is removed from the tooth base of the pinion, so that the tooth head of the ring gear also on the point of deepest tooth engagement is free by an amount of, for example, 0.02 to 0.03 H. This completes the construction of the ring gear and pinion.
  • Gerotor pumps according to the invention are suitable for a wide variety of purposes. In particular, they are suitable as lubricating oil pumps for motor vehicle piston engines, in which the pinion sits directly on the crankshaft and the ring gear in a housing fixed to the engine housing. Surprisingly, gear pumps according to the invention are insensitive to fluctuations in the center distance to such an extent that they can withstand the large displacements of the crankshaft of a cylinder internal combustion engine as measured by the dimensions of the relatively small pump.
  • However, the use of the gerotor pump according to the invention is not restricted to this purpose. It is also useful for a variety of other purposes, such as as a hydraulic pump.

Claims (10)

1. An annular gear pump having a housing (18, 19, 20), an internally toothed annular gear-wheel (10) with eight to sixteen teeth, rotatably mounted in the housing, and a pinion (12) carried by a drive shaft (22), the pinion having one tooth less than the annular gear-wheel (10) and meshing with the annular gear-wheel (10), whereby the sealing between suction chamber and pressure chamber is effected opposite the point of deepest engagement of the gear-wheel by sliding of the tips of the teeth of the pinion (12) on the teeth of the annular gear-wheel and at the point of deepest engagement of the gear-wheel by bearing of the driving flanks of the teeth of the pinion (12) against the teeth of the annular gear-wheel, while, furthermore, the tips of the teeth of the pinion (12) go freely in the gaps between the teeth of the annular gear-wheel (10) and the tooth profile of the pinion (12) is defined by rolling thereof in the annular gear-wheel (10), characterised in that the teeth (11) of the annular gear-wheel (10) have an approximately trapezoidal shape with convexly curved flanks and tips and that the circle of contact of the annular gear-wheel (10) extends outside the circle round the centre (MH) of the annular gear-wheel through the lower third of the height of the teeth of the annular gear-wheel (10).
2. An annular gear pump as claimed in claim 1, characterised in that the extent of the teeth (11) of the annular gear-wheel and the extent of the gaps between the teeth of the annular gear-wheel, measured in the circumferential direction over the circle through half the height (H) of the teeth of the annular gear-wheel, are substantially equal.
3. An annular gear pump as claimed in claim 1 or 2, characterised in that the width of the tips of the teeth (without rounding) of the annular gear-wheel (10) aounts to 0.65 to 0.7 times and the width of the gaps between the teeth at the theoretical dedendum circle (FH) of the annular gear-wheel (10) (without rounding) amounts to 1.05 to 1.1 times the theoretical tooth height (H) of the annular gear-wheel (10).
4. An annular gear pump as claimed in claims 1 to 3, characterised in that the radius of curvature (rm) of the tips of the teeth of the annular gear-wheel (10) amounts to about 2 to 2.4 times, preferably 2.2 to 2.3 times, the theoretical height (H) of the teeth of the annular gear-wheel (10).
5. An annular gear pump as claimed in claims 1 to 4, characterised in that the radius of curvature (ro) of the flanks of the teeth of the annular gear-wheel (10) amounts to about 3.3 to 3.7 times, preferably 3.4 to 3.6 times the theoretical height (H) of the teeth of the annular gear-wheel (10).
6. An annular gear pump as claimed in one of the claims 1 to 5, characterised in that the curvature of the tips of the teeth of the annular gear-wheel is an arc of a circle, the centre of which lies on the radius line through the tooth centre outside the dedendum circle (FH), and that the flanks of the teeth of the annular gear-wheel (10) extend along arcs of circles the centres of which each lie outside the dedendum circle (FH).
7. An annular gear pump as claimed in one of the claims 1 to 6, characterised in that the tooth flanks remote from one another of each two adjacent teeth (11) of the annular gear-wheel (10) lie on a common arc of a circle.
8. An annular gear pump as claimed in one of the claims 1 to 7, characterised in that the edges between the flanks of the teeth and the tips of the teeth of the annular gear-wheel (10) are each rounded along an arc which merges continuously both into the arc defining the tooth flank and into the arc defining the tip of the tooth and which has a radius which is of the order of magnitude of a third of the theoretical height (H) of the teeth of the annular gear-wheel.
9. An annular gear pump as claimed in one of the claims 1 to 8, characterised in that the base of the gaps between the teeth of the pinion (12) is also relieved.
10. An annular gear pump as claimed in one of the claims 1 to 9, characterised in that the annular gear-wheel (10) has nine to fifteen, preferably eleven to thirteen, teeth.
EP81103438A 1980-07-10 1981-05-06 Annular gear pump Expired EP0043899B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE3026222A DE3026222C2 (en) 1980-07-10 1980-07-10
DE3026222 1980-07-10

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EP0043899A1 EP0043899A1 (en) 1982-01-20
EP0043899B1 true EP0043899B1 (en) 1984-01-25

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EP81103438A Expired EP0043899B1 (en) 1980-07-10 1981-05-06 Annular gear pump

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US (2) US4398874A (en)
EP (1) EP0043899B1 (en)
JP (1) JPS6257835B2 (en)
AU (1) AU546238B2 (en)
BR (1) BR8104391A (en)
CA (1) CA1168510A (en)
DE (1) DE3026222C2 (en)
MX (1) MX154462A (en)

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DE3243067C2 (en) * 1982-11-22 1991-12-05 Schwaebische Huettenwerke Gmbh, 7080 Aalen, De
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MX154462A (en) 1987-08-28
AU7266381A (en) 1982-02-18
US4432712A (en) 1984-02-21
DE3026222C2 (en) 1987-10-01
CA1168510A1 (en)
JPS5779290A (en) 1982-05-18
AU546238B2 (en) 1985-08-22
CA1168510A (en) 1984-06-05
EP0043899A1 (en) 1982-01-20
US4398874A (en) 1983-08-16
JPS6257835B2 (en) 1987-12-02
BR8104391A (en) 1982-03-30
DE3026222A1 (en) 1982-02-04

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