EP2732164A1

EP2732164A1 - Gear ring pump

Info

Publication number: EP2732164A1
Application number: EP12746262.0A
Authority: EP
Inventors: Andreas Blechschmidt
Original assignee: Geraete und Pumpenbau GmbH Dr Eugen Schmidt
Current assignee: Nidec GPM GmbH
Priority date: 2011-07-14
Filing date: 2012-06-27
Publication date: 2014-05-21
Anticipated expiration: 2032-06-27
Also published as: DE102011107157B4; ES2553790T3; DE102011107157A1; WO2013007233A1; US20140154125A1; EP2732164B1; WO2013007233A4; US9309885B2

Abstract

The invention relates to a gear ring pump, in particular for use in small pump assemblies which are preferably driven by an electric motor, which are produced as pump kits, and which are used in vehicle and engine construction. The aim of the invention is to develop a gear ring pump which can be used in pump assemblies with a small housing outer diameter, the pump control times of which can be easily modified with respect to the production process in accordance with the respective customer request, and which always ensures an optimal axial gap even when using very inexpensive assemblies, such as pump housings made of aluminum and impellers made of steel, even under the extreme use conditions of an oil pump in conjunction with an internal combustion engine. The gear ring pump according to the invention is characterized in particular in that the pump bearing (6) is arranged in the housing cover (5), and a port support (18) is mounted in the pump housing (1) between the impeller set (8) and the end wall (3) of the working chamber (2) in a movable manner in the direction of the driveshaft (7) such that the port support is prevented from rotating. The port support is equipped with a suction kidney (12) and a pressure kidney (13) which pass through the port support (18) separately from each other across the entire width of the port support (18), wherein the thickness of the port support (18) approximately matches the thickness of the impeller set (8) but can also project past the thickness of the impeller set by up to 20%. The thermal expansion coefficient of the port support (18) is approximately 70% to 120% greater than the thermal expansion coefficient of the pump housing (1). The driveshaft (7) which is rotationally fixed to the inner rotor (9) does not protrude into the port support (18) under any circumstance. The port support (18) is designed or coated so as to be wear-resistant at the end face adjacent to the impeller set (8), and/or a sheet metal slide (25) which is rotationally fixed to the port support is arranged between the impeller set (8) and the port support (18).

Description

Annular gear pump

The invention relates to a gerotor pump, in particular for use in small pump units, which are preferably produced by electric motor operated as a modular pump and used in vehicle and engine.

Toothed ring pumps, for example in the design of gerotor pumps are used in automotive and engine construction, inter alia, in internal combustion engines as fuel pumps or oil pumps.

The wheelset used in gerotor pumps, consists of an externally toothed inner rotor and an internally toothed outer rotor, wherein the inner rotor is rotatably connected to the drive shaft and having fewer teeth than the outer rotor, and the outer rotor is rotatably mounted in a cylindrical chamber of the pump housing so that the teeth of the eccentric to the outer rotor mounted inner rotor partially mesh with the teeth of the outer rotor. In the pressure and suction area of the wheelset kidney-shaped pump chambers (pressure and Saugniere / n) are arranged in the pump housing, which are connected via connection channels directly to the pump housing arranged pressure and suction connection lines and ensure that the liquid to be pumped from the suction line via the Wheelset is pressed into pressure connection line.

US Pat. No. 7,614,227 B2 describes a hydrostatic drive unit of a lawn tractor based on a gerotor pump and a gerotor motor, in which the oil volume flow from the pump to the hydraulic motor is regulated by means of a rotary control valve in the embodiment of a rotary plate. In this disclosed in US 7,614,227 B2 design, a stationary bearing plate is disposed between the rotary plate and the gerotor motor, in the center of a bearing bore, for rotatably supporting the motor shaft, is arranged. In addition, two kidney-shaped passage openings are arranged in this bearing plate, in the region of the pump chambers of the gerotor motor, so that the bearing plate at the same time takes over the task of a guide body and in connection with the bearing plate adjacent assemblies, according to the solution presented in US 7,614,227 B2, a Regulation of the traction drive of the lawn tractor, ie a regulation of its speed and its direction of travel, can be guaranteed.

The gerotor pumps used as oil pumps in the internal combustion engines are used there for engine lubrication, which is known e.g. in motor vehicles over a temperature range of minus 40 ° C to the range of hot idling operation of about 160 ° C must be guaranteed.

Since almost all pump housings are made of other materials for cost and weight savings, such as the gear sets located in the respective pump housing, for example, the pump housings are often die-cast aluminum and the gear sets are made of sintered steel, varying over the wide operating range / temperature range of minus 40 ° C to about 160X, due to the different thermal expansion coefficients of aluminum and steel inevitably also the axial play between the gear set and the pump housing as a function of the current operating temperature. In this case occur at low operating temperatures, due to narrow gaps, usually friction losses and high operating temperatures due to large gaps, losses in volumetric efficiency, which can be up to 50% to 60% of the best for each gerotor pump assembly volumetric efficiency.

The volumetric efficiency decreases approximately linearly with increasing temperatures.

In the prior art, therefore, a variety of solutions for optimizing the axial gap / axial clearance have been proposed.

For example, DE 103 31 979 A1 discloses a toothed ring pump used as an oil pump whose axial clearance is optimized by means of spacer elements arranged in the region of the screw connections between the pump cover and the pump flange in that these spacer elements have a lower thermal expansion coefficient than the pump cover, the pump flange and / or the gear set.

By installing such spacers, such as nickel steel, reduces the axial clearance at high temperatures and increases at low temperatures.

The incorporation of such spacers leads to an increase in the volumetric efficiency over conventional pumps made of die-cast aluminum with steel gear sets of up to 40 to 50%, but it has the disadvantage that the spacers necessarily located outside of the pump rotor diameter and within the pump housing must be that this solution requires a substantial radial increase in the space of the respective pump.

A design of a gerotor pump with a smaller outer diameter is known from DE 10 2008 054 758 A1. In this design, two interconnected, the gerotor surrounding the Axialspaltminimierung Housing parts braced against each other in addition to the connection force by means of suitable spring elements.

However, this solution has the disadvantage that due to the applied spring preload on the rotor components inevitably occur on the front side of the rotor friction moments that have high efficiency losses result.

At the same time increases due to integrated in the pump housing construction and functional elements, such as the bearings for the drive shaft, to be arranged in the pump housing suction and pressure kidneys and the associated connection channels inevitably with smaller size of the manufacturing and assembly costs.

In addition, the gap geometries disproportionately affect the efficiency with a smaller size.

In order to reduce the production accuracy and thus the production costs, in particular with smaller size, it has been proposed in the prior art to modularly construct these housings, in particular of small gerotor pumps, i. from several components.

These types of construction are between the adjacent components

Elastomer seals arranged for tolerance compensation.

These solutions with elastic tolerance compensation occur in

Distort the adjacent components inevitably "residual stresses", which in turn lead to friction moments on the front sides of the wheelset.

However, if the adjacent components are "strained" so that between them still tolerance-related gaps remain, then occur with increasing operating temperature on the wheelset frontal leakage losses, which, as already explained, affect the efficiency of the very small-built gerotor pumps disproportionately strong.

Now these, either from leakage losses resulting, or from the "strain" of Elastdomerdichtungen against the wheelset To reduce the resulting efficiency losses, the production accuracy and thus the production cost must be increased disproportionately for Axialspaltkompensation, especially in very small-built gerotor pumps.

For Axialspaltkompensation be used on both sides of the Pumpenlaufradsatz adjacent, axially displaceable sealing plates in the art on which the Pumpenlaufradsatz abgewanden side of Elastdomerdichtungen cavities are arranged, which are then pressurized in the operating state of the pump.

However, in small-size gear pumps this solution is axially displaceable sealing plates is just arranged adjacent to both sides of the impeller set, not suitable to achieve with reasonable manufacturing cost to an optimal efficiency ^'.

However, the use of these axially displaceable sealing plates with pressurization of a Elastomers sealed enclosing, arranged between the adjacent components cavity also causes the same time that the cavity internal pressure also acts on the edge edge of the Elastdomerdichtung, so that causes with decreasing pump size of the axial tolerance compensation with pressurized Elastdomerdichtungen that the ratio of the "Elastdomerdichtungskraft" to the hydraulically generated force is always unfavorable, and that with smaller size of the gerotor pumps (eg in gerotor pumps with a flow rate of about 8 l / min and external dimensions of about 40 mm x 40 mm x 40 mm) outweigh the incalculable "disturbing forces" and then dominate the overall efficiency of the pump.

The invention is therefore based on the object to develop a gerotor pump, which eliminates the aforementioned disadvantages of the prior art, and in particular at small, ie also in the outer diameter of the Housing small pumping units, which are preferably operated by electric motor and manufactured as a modular pump that largely the same Gehäuserohteile be used in geometry, can be used, wherein the to be developed ring gear pump also according to the customer's request in the timing of the pump manufacturing technology should be easily modifiable , so that always a fluidically optimal behavior of the pump according to the invention is ensured, it should be very inexpensive to produce the ring gear pump to be developed even in very small pump sizes, and also with the use of very cost-effective components, such as pump housings made of aluminum and pump steel, even under extreme operating conditions, such as an oil pump in conjunction with an internal combustion engine, ie over the temperature working range of such oil pump, from about - 40 ° C to about + 160 ° C away, always e ensure optimum axial gap (and thereby minimal losses), so over the entire speed and temperature range of such pump away always a high overall efficiency is guaranteed, the developing ring gear pump is of course always reliable throughout the speed and temperature range, robust and susceptible to interference ,

According to the invention this object is achieved by a gerotor pump with the features of the main claim of the invention.

Advantageous embodiments, details and other features of the invention will become apparent from the dependent claims and the following description of the embodiment of the invention in conjunction with the drawings for the solution according to the invention. Below, the invention will now be explained in more detail with reference to an embodiment in conjunction with five representations.

It shows the

Figure 1: an exploded view of an inventive

Toothed ring pump in the design of a gerotor pump in a perspective view from above, in the longitudinal direction of the drive shaft 7 from the direction of the housing cover 5;

Figure 2 is an exploded view of the ring gear pump according to the invention in the design of a gerotor pump in a perspective view from above and from the direction of the pump housing 1;

Figure 3 is an exploded view of the ring gear pump according to the invention in the design of a gerotor pump in a perspective view from the front, from the direction of the drive shaft 7 and the housing cover 5;

Figure 4: an assembly drawing of the invention

Toothed ring pump in the design of a gerotor pump in the front view (with a view of the lid) with the representation of the cutting guide for Figure 5;

Figure 5: an assembly drawing of the invention

Toothed ring pump in the form of a gerotor pump, in the side view, in partial section with the cutting guide according to Figure 4.

The illustrated in Figures 1 to 5, the invention ring gear pump with a pump housing 1, one arranged in the pump housing 1 Working space 2 with arranged in the end wall 3 of the working space 2 in the pump housing 1 inlet and Ausströmbereichen, arranged on the pump housing 1, sealed by a seal 4 housing cover 5, arranged with a rotatably mounted in the pump housing 1, mounted in a pump bearing 6 drive shaft 7 at a wheelset 8 is arranged, which consists of a rotatably connected to the drive shaft 7 externally toothed inner rotor 9 and an internally toothed outer rotor 10 which is rotatably mounted in a rotor bearing 1 1 in the cylindrical working space 2 of the pump housing 1 such that the teeth of the eccentrically to the outer rotor 10 mounted inner rotor 9 in regions with the teeth of the outer rotor 10 mesh with one or both sides in the suction region of the wheelset 8 arranged / arranged Saugniere / n 12 and one or both sides in the pressure range of the wheelset 8 arranged / arranged Druckniere / n thirteenth , wherein the Saugniere / n 12 via ei NEN / more arranged in the pump housing 1 suction channel 14 / arranged suction channels 14 is connected to at least one arranged on the pump housing 1 suction port 15 / and the Druckniere / n 13 via one / more arranged in the pump housing 1 pressure channel 16 / pressure channels 16 with at least one on Pump housing 1 arranged pressure port 17 is connected / are, and the liquid to be pumped is pressed from the suction port 15 via the arranged in the pump housing 1 impeller 8 into the pressure port 17, is characterized inter alia by the fact that the pump bearing 6 is arranged in the housing cover 5

Essential to the invention is in this context that in the pump housing 1 between the wheelset 8 and the end wall 3 of the working space 2 against rotation in the direction of the drive shaft 7 slidably mounted port carrier 18 is arranged, in which both a suction kidney 12 and a pressure kidney 13 is arranged and both each separated from one another, the port carrier 18 over the entire thickness of the port carrier 18, this in the form of an inlet chamber 19 connected to the suction kidney 12, as well as on the other hand connected to the pressure kidney 13 Ausströmströmkammer 20th penetrate, wherein the thickness of the port carrier 18 corresponds approximately to the thickness of the wheelset 8 and this can also exceed by up to 20%, and the coefficient of thermal expansion of the port carrier 18 is about 70% to 120% higher than the thermal expansion coefficient of the pump housing 1, and that the drive shaft 7, which is non-rotatably connected to the inner rotor 9, by no means protrudes into (or is supported in) the port carrier 18.

It is also characteristic that the port carrier 18 is wear-resistant on the end face adjacent to the wheelset 8 or is wear-resistant coated, or that a sliding plate 25 rotatably connected to the port carrier 18 is arranged between the wheelset 8 and the port carrier 18, whereby between the wheelset 8 and the port carrier 18 in addition to the friction losses and the wear is minimized, so that by means of the solution according to the invention a long service life can be ensured with high efficiency.

In the figure 1 is shown as one of the possible designs of this feature, arranged between the wheelset 8 and the port carrier 18 sliding plate 25, wherein on the sliding plate 25, a latching nose 26 is arranged, which engages positively with a arranged on the port carrier 18 locking groove 27 in operative connection , And thereby the sliding plate 25 rotatably connected to the port carrier 18.

It is also essential that in the sliding plate 25 also one of the suction kidney

12 of the port carrier 18 associated suction kidney 12 and also one of the pressure kidney

13 of the port carrier 18 associated pressure kidney 13 are arranged so that an unhindered passage of the pumped medium "through the sliding plate through" is given.

It is also advantageous in this context if a shaft guide bore 28 is arranged in the sliding plate 25.

By introducing the shaft guide bore 28, the sliding plate 25 is reduced in its flexural rigidity, thereby better applying and adapting to the wheelset 8 and the port support 18 is possible. simultaneously can be achieved with the shaft guide bore 28, a slight projection of the drive shaft 7.

According to the invention is that the housing cover 5 via arranged in the pump housing 1 positioning pins 21 and the housing cover 5 associated Positionierkerben 22 against rotation on the pump housing 1, and the port carrier 18 by means of eccentrically arranged in the port carrier 18 pin guide bore 24 and one in the end wall 3 of the working space 2 of Pin guide bore 24 associated arranged guide pin 23 is axially displaceably mounted in the pump housing 1.

This arrangement of the invention allows in connection with the inventive arrangement of the port support 18 in the axial direction next to the wheelset 8 of the ring gear pump according to the invention, since the port carrier 18 the inflow and outflow of the pump in its functional geometry maps that in conjunction with the invention, outer cylindrical geometry of the port carrier 18 this easily rotated within certain limits in the pump housing 1, and exactly, eg by guide pins 23 in the pump housing 1, can be positioned securely.

Thus, by means of the inventive use of the port support 18 according to the invention by the rotation angle-related adaptation described above for the first time easily, easily and also very cost-effective, the timing of the pump to the particular application of the pump can be optimized fluidically.

In addition, the port carrier 18 according to the invention also serves to simultaneously ensure optimization of the axial gap.

For this purpose, materials are used according to the invention for the port carrier 18 whose coefficient of thermal expansion preferably has twice the value of the thermal expansion coefficient of the housing material.

The thickness of the port carrier 18 corresponds approximately to the thickness of the wheelset. 8 However, in order to effect an overcompensation of the axial gap with correspondingly desired axial basic play between the wheelset 8 and the port carrier 8, the thickness of the port carrier 18 can be increased, for example, to approximately 120% of the thickness of the wheelset 8.

In the present embodiment, with a pump housing 1 made of aluminum, 18 modified thermosets were used as materials for the port carrier, the thickness of the port support of course varies depending on the base material used in each case for the port carrier 18.

For the port carrier 18, however, it is also possible to use specially modified thermoset materials, which are e.g. by targeted admixture of friction reducing substances significantly improve the running behavior of the adjacent arranged wheelset.

It is also according to the invention if the port carrier 18 is made of sintered and resin-bound sodium chlorides.

By using sintered and resin-bound sodium chlorides to prepare the port support 18 a predetermined axial thermal expansion of an aluminum pump housing ¹ may with a coefficient of thermal expansion for aluminum of about 23 x 10 ^"6 ^K" through a port support of sintered and resin-bound sodium chlorides, wherein a thermal expansion coefficient for sodium chloride of about 40 ... 44 x 10 ^"6 K ^{" 1} , effectively, ie, compensated for with a relatively small thickness dimension of a port carrier 18 made of sintered and resin-bound sodium chloride.

By means of the solution according to the invention, therefore, when using different materials for housing and rotor, the axial gaps depending on the respective operating temperature are always optimized in the entire temperature working range of the pump, i. it is cost effective to ensure optimal dynamic axial gap compensation.

Depending on the choice of material for the port carrier 18 in connection with the dimensioning of the thickness of the port carrier 18 it will also possible to make the axial gaps larger at low temperatures and at higher temperatures by significantly greater length expansion of the port carrier 18 to reduce the axial play.

Such a tendency "supports" the natural viscosity behavior of various types of oil and thus leads to an overall much more efficient working pump.

Another advantage of the solution according to the invention consists in the fact that in the Axialspaltkompensation invention presented here, the wheelset 8 remains free of axial loads, so that the resulting friction moments are avoided, which inevitably always lead to efficiency losses.

The inventively desired temperature-compensating effect of the inventively placed in the axial direction next to the wheelset 8 invention port carrier 18 causes temperature increase and consequent axial growth of the working space 2 in the pump housing 1, in which the wheelset 8 and the port support 18 are housed, that by a clear higher thermal expansion of the port support 18 according to the invention, the axial growth of the working space 2 is balanced with simultaneous attention to the growth of the wheelset 8.

In the case of overcompensated length compensation, it is possible according to the invention to set the axial basic play relatively low at low temperatures, and thereby to accommodate the viscosity behavior of the medium to be conveyed, in order to reduce the drive power in the low temperature range of the ring gear pump according to the invention, and thus also the efficiency in this operating point to increase significantly.

At the same time, the solution according to the invention, as a result of the arrangement according to the invention of the port carrier 18 according to the invention, in conjunction with all the effects already described, at the same time also enables the production of pump units of small construction in the outer diameter of the housing. REFERENCE SYMBOL

1 pump housing

2 working space

3 front wall

4 seal

5 housing cover

6 pump bearings

7 drive shaft

8 wheelset

9 inner rotor

10 outer rotor

1 1 rotor bearing

12 suckling kidneys

13 print kidney

14 suction channel

15 suction connection

16 pressure channel

17 pressure connection

18 port carriers

19 inflow chamber

20 outflow chamber

21 positioning pin

22 positioning notch

23 guide pin

24 pin guide hole

25 sliding plate

26 latch

27 locking groove

28 shaft guide hole

Claims

claims

1. gerotor pump with a pump housing (1), one in the pump housing (1) arranged working space (2) in the end wall (3) of the working space (2) in the pump housing (1) arranged inlet and / or Ausströmbereichen, one on the pump housing ( 1) arranged by means of a seal (4) sealed housing cover (5), with a rotatably mounted in the pump housing (1) arranged by a in a pump bearing (6) drive shaft (7) on which a wheelset (8) is arranged, the from a rotatably connected to the drive shaft (7) externally toothed inner rotor (9) and an internally toothed outer rotor (10) which is rotatably mounted in a rotor bearing (1 1) in the cylindrical working space (2) of the pump housing (1) such that the Teeth of the eccentric to the outer rotor (10) mounted inner rotor (9) in regions with the teeth of the outer rotor (10) mesh with one or both sides in the suction region of the wheelset (8) arranged / arranged Saugniere / n (12 ) and one or both sides in the pressure range of the wheelset (8) arranged / arranged Druckniere / n (13), wherein the Saugniere / n (12) via one / more in the pump housing (1) arranged suction channel (14) / arranged suction channels (14 ) is connected to at least one of the pump housing (1) arranged suction port (15) is / the Druckniere / n (13) via one / more in the pump housing (1) arranged pressure channel (16) / arranged pressure channels (16) with at least one on Pump housing (1) arranged pressure port (17) is / are connected, and the liquid to be pumped from the suction port (15) via the in the pump housing (1) arranged impeller set (8) is pressed into the pressure port (17), characterized that the pump bearing (6) in the housing cover (5) is arranged, and that in the pump housing (1) between the wheelset (8) and the end wall (3) of the working space (2) against rotation in the direction of the drive shaft (7) slidably mounted port carrier (18) is arranged, in which both a suction kidney (12), as well as a pressure kidney (13) are arranged and both separately from each other the port carrier (18), over the entire thickness of the port carrier (18), in the form of a Suction kidney (12) connected inflow chamber (19) and one with the pressure kidney (13) connected outflow flow chamber (20) penetrate, wherein the thickness of the port carrier (18) corresponds approximately to the thickness of the wheelset (8) and this but also to can project beyond 20%, wherein the thermal expansion coefficient of the port carrier (18) about 70% to 120% above the thermal expansion coefficient of the pump housing (1), and that the non-rotatably connected to the inner rotor (9) drive shaft (7) keinfa lls protrudes into the port carrier (18), and that the port carrier (18) on the front wheel of the wheelset (8) adjacent wear-resistant, or coated, and / or that between the wheelset (8) and the port carrier (18) a rotationally fixed to the port carrier connected sliding plate (25) is arranged.

2. Toothed ring pump according to claim 1, characterized in that the housing cover (5) arranged in the pump housing (1) positioning pins (21) and the housing cover (5) associated Positionierkerben (22) against rotation on the pump housing (1), and the port carrier (18 ) is mounted axially displaceable in the pump housing (1) by means of an eccentrically arranged in the port carrier (18) pin guide bore (24) and one in the end wall (3) of the working space (2) of the pin guide bore (24) arranged guide pin (23).

3. Toothed ring pump according to claim 1, characterized in that the port carrier (18) is made of modified thermosets.

4. Toothed ring pump according to claim 1, characterized in that the port carrier (18) is made of sintered and resin-bound sodium chlorides.

5. Toothed ring pump according to claim 1, with a between the wheelset (8) and the port carrier (18) arranged sliding plate (25), characterized in that in the sliding plate (25) also one of the suction kidney (12) of the port carrier (18) associated with Saugniere (12) and a pressure kidney (13) of the port carrier (18) associated pressure kidney (13) are arranged.

6. Toothed ring pump according to claim 5, characterized in that on the sliding plate (25) a latching lug (26) is arranged, which engages positively with a on the port carrier (18) arranged latching groove (27) in operative connection.

7. Toothed ring pump according to claim 5, characterized in that in the sliding plate (25) has a shaft guide bore (28) is arranged.