WO2014198597A1

WO2014198597A1 - Pump for delivering a liquid

Info

Publication number: WO2014198597A1
Application number: PCT/EP2014/061546
Authority: WO
Inventors: Rolf BRÜCK; Jan Hodgson
Original assignee: Emitec Gesellschaft Für Emissionstechnologie Mbh
Priority date: 2013-06-13
Filing date: 2014-06-04
Publication date: 2014-12-18
Also published as: DE102013106170A1; KR20160017091A; US20160138589A1; JP2016521829A; CN105492770A; EP3008342A1

Abstract

A pump (1) for delivering a liquid, having a pump housing (2) with at least one inlet (3) and at least one outlet (4), wherein, on the pump housing (2), there is arranged an eccentric (5) which, with an axis (6), is rotatable relative to the pump housing (2), and wherein a deformable element (7) is arranged between the pump housing (2) and the eccentric (5), wherein the deformable element (7) delimits at least one delivery path (8) from the at least one inlet (3) to the at least one outlet (4) and forms at least one displaceable seal (9) of the delivery path (8), which displaceable seal partitions off at least one closed pump volume (10) in the delivery path (8), wherein, by means of a movement of the eccentric (5), the at least one displaceable seal (9) can be displaced in a delivery direction (11) from the inlet (3) to the outlet (4) for the purpose of delivering the liquid along the delivery path (8), wherein the inlet (3) and the outlet (4) have an angular spacing (13) to one another in a circumferential direction (12) about the axis (6), and the seal (9) spans, in the circumferential direction (12), an angle segment (14) in which the delivery path (8) is closed, wherein the angle segment (14) is larger than the angular spacing (13).

Description

Pump for conveying a liquid

The invention relates to a pump for conveying a liquid, which is particularly suitable to promote a liquid additive in the exhaust pipe device of an internal combustion engine.

For cleaning the exhaust gases of internal combustion engines, exhaust gas treatment devices are known in which a liquid additive is added to clean the exhaust gases. An exhaust gas purification process carried out in such exhaust gas treatment devices is the selective catalytic reduction (SCR) process, in which nitrogen oxide compounds in the exhaust gas are reduced with the aid of a reducing agent. As a reducing agent in particular ammonia is used. Ammonia is often not stored directly in the motor vehicle, but in the form of a liquid additive, which is a precursor solution of the reducing agent. This liquid additive can be converted into reducing agent in the exhaust gas (in the exhaust gas treatment device) or exhaust gases in a dedicated reactor to reducing agent. As a liquid additive, urea-water solution is used for the SCR process. A 32.5% urea-water solution is available under the trade name AdBlue®.

For conveying liquid additive from a tank and for the metered provision of the liquid additive to the exhaust pipe device, at least one pump is provided. Such a pump should be as inexpensive and reliable as possible. It is particularly advantageous if the pump can also take over a metering function, that is, very precisely conveys a predetermined amount of the liquid additive. In addition, the smallest possible pressure fluctuations in the liquid additive should be generated in the promotion, because they can negatively influence the spray pattern of a nozzle for atomization of the liquid additive in the exhaust gas treatment device. Another requirement is that the pump should be as quiet as possible. Another important aspect of pumps for conveying liquid additives is that the liquid additives used for exhaust gas purification can freeze at low temperatures. The above-mentioned urea-water solution freezes, for example, at -11 ° C. Such low temperatures can be in the automotive field z. B. occur during long downtime in winter, with the liquid additive expands during freezing. The pump should therefore also be designed so that it is not damaged by freezing liquid additive. On this basis, it is an object of the present invention to solve the problems described in connection with the prior art or at least alleviate. In particular, a particularly advantageous pump for conveying a liquid is described, which is suitable for use in the technical field of exhaust gas purification.

These objects are achieved with a pump according to the features of claim 1. Further advantageous embodiments of the pump are given in the dependent formulated claims. The features listed individually in the claims can be combined with each other in any technologically meaningful manner and can be supplemented by explanatory facts from the description, with further embodiments of the invention being shown.

The invention relates to a pump for delivering a liquid, comprising a pump housing having at least one inlet and at least one outlet, wherein on the pump housing, an eccentric is arranged, which is rotatable with an axis relative to the pump housing. Furthermore, a deformable element is arranged between the pump housing and the eccentric, with the deformable element at least one conveying path being delimited by the at least one inlet to the at least one outlet and at least one displaceable seal of the conveying path being formed in the conveying path separates a closed pump volume and by moving of the eccentric for conveying the liquid along the conveying path in a conveying direction from the inlet to the outlet is displaceable. The inlet and outlet also have an angular distance from one another in the circumferential direction about the axis and the seal spans in the circumferential direction an angular section in which the conveying path is closed, wherein the angular section is greater than the angular distance.

A pump with the construction described can be referred to as orbital pump. Between the pump housing and the eccentric exists a gap in which the deformable element is arranged. The conveying path is arranged within the gap and the conveying path is limited at least by the (individual) deformable element and optionally additionally by the pump housing and / or the eccentric. The deformable element is preferably arranged in the gap between the eccentric and the pump housing in such a way that it is squeezed or compressed in the region of the at least one seal between the housing and the eccentric so that the gap in the region of the seal is completely away from the deformable element is closed and / or the gap there no cross-sectional area more, which forms a (freely flowable) conveying path. The gap or the conveying path is thereby sealed fluid-tight in the region of the at least one seal. The gap or the delivery path is filled with the liquid during operation of the pump.

Along the conveying path, the at least one seal divides the conveying path, so that at least one closed pump volume is formed. By the term "closed pump volume" is meant in particular a volume within the conveying path, which is closed along the conveying path at least on one side by a seal. Preferably, during operation of the pump, a plurality of closed pump volumes are shifted from the inlet to the outlet to deliver the liquid. In this case, a closed pump volume is formed in the vicinity of the inlet (defined closed) and then dissolved at the outlet (reopened). At the inlet is a closed pump volume (only) on one side (downstream) closed by a seal and upstream connected to the inlet, so that the liquid can flow through the inlet in the closed pump volume. At the outlet, the closed pump volume is (only) closed on one side (but upstream) by a seal and connected downstream with the outlet, so that the liquid can flow out through the outlet from the closed pump volume. In between there exists (on the way from the inlet to the outlet) a phase in which the closed pump volume is closed on both sides by a seal.

The pump housing of the pump is preferably a ring or a cylindrical chamber in which the eccentric is arranged inside (centric). The pump housing may also be considered as the (outer) stator of the pump, while the eccentric may be referred to as the (inner) rotor. According to a further embodiment of the pump, it is possible that the pump housing forms an inner stator, which is surrounded by the eccentric. Then the eccentric forms an outer rotor. The inlet and the outlet are arranged on the pump housing and allow the inflow and outflow of the liquid in the pump housing or in the conveying path.

It is particularly preferred if the deformable element is a hose which is inserted in an arcuate gap between the eccentric and the pump housing and connects the inlet to the outlet. The (one-piece and / or inside the pump housing inside and / or fixed) hose is preferably fluid-tightly connected to the inlet and to the outlet, so that the liquid enter through the inlet or through the outlet in the conveying path in the hose or can escape. The seal is formed by the fact that the hose is compressed there by the eccentric and the pump housing. The pump is also advantageous when the deformable member is a deformable membrane and the delivery path from the at least one inlet to the at least one outlet from the pump housing and the deformable membrane is at least partially limited.

In this embodiment, the conveying path between the (integral and / or inside the pump housing and / or fixed) deformable diaphragm and the pump housing is formed and constitutes a gap between the pump housing and the deformable membrane. To form the seal, the deformable membrane of the Eccentric pressed against the pump housing, so that the deformable diaphragm rests against the pump housing and between the deformable diaphragm and the pump housing remains no gap. The deformable membrane is preferably shaped in sections in a U-shape around the pump housing and adhesively bonded and / or pressed to the pump housing.

In any case, the deformable element preferably consists of a flexible rubber material, which has a high deformability. Particularly preferred are deformable elements of elastomeric materials, such as rubber or latex. To increase the durability and / or to produce and maintain flexibility, the material of the deformable element may contain additives. Preferably, the deformable element is flexible in all directions (axial, radial and circumferential). However, it is also possible that the deformable element has a partially directed flexibility. For example, it may have a higher flexibility in the radial direction than in the circumferential direction and in the axial direction. Deformation of the deformable element in one direction typically also causes deformation in other spatial directions. The deformable element expands, for example, in the axial direction and / or in the circumferential direction when it is compressed in the radial direction. At least one stationary seal is also provided on the pump, which prevents unwanted backflow of the liquid from the outlet to the inlet. The stationary seal prevents a direct bypass of the delivery path between the outlet and the inlet occurs. By bypass is meant here that the liquid does not pass the entire length of the conveying path but takes a direct shorter path from the outlet back to the inlet.

If the deformable element is a deformable membrane, then this is preferably annular and inserted into a gap between the eccentric and the housing. The conveying path forms a circular arc segment, and extends in sections (in the conveying direction from the inlet to the outlet) along the annular membrane. The stationary seal is disposed along the annular diaphragm outside the circular arc segment of the delivery path between the inlet and the outlet. The stationary seal between the inlet and the outlet reliably prevents backflow. The stationary seal may for example be formed by a dent or a pin of the pump housing, so that a gap between the pump housing and the eccentric is so far reduced that the membrane is always squeezed regardless of the position of the eccentric in the stationary seal, so that no bypass to the conveying path is formed or no backflow is possible. The stationary seal can also be formed by a sectionwise (in the region of the stationary seal) thickening of the deformable membrane. By such a thickening of the membrane can also be ensured that a gap between the eccentric and the pump housing in the region of the stationary seal is always closed.

The stationary sealing can in principle also be achieved by virtue of the fact that the deformable membrane in the area of the stationary seal on the pump housing housing fluid-tight fastened (for example, screwed and / or glued) is. By such measures, a backflow between the deformable membrane and the pump housing is also effectively prevented. If the deformable element is a hose, no special measures are required to form a stationary seal because a (fluid-tight) hose connected to the inlet and to the outlet can not bypass. The stationary seal is then implicitly formed by the wall of the hose.

The eccentric is preferably designed in several parts. The eccentric preferably has an inner region which performs an eccentric rotational movement. In addition, an outer bearing ring may be provided, which surrounds the inner region. Between the inner region and the outer bearing ring is preferably at least one bearing. This bearing can be a ball bearing or a roller bearing. The inner region of the eccentric executes a rotary movement about the axis during operation. Due to the eccentric arrangement and possibly also due to the outer shape of the eccentric results in an eccentric movement of a surface of the eccentric. This eccentric movement is transmitted to the outer bearing ring. By a bearing between the inner portion and a bearing ring, an eccentric rotation of the inner portion can be converted into an eccentric wobble of the bearing ring, without the Drehbewegungsanteil is transmitted. The fact that the movement of the bearing ring has no rotational movement component makes it possible to reduce shear stresses in the deformable element and internal friction forces of the pump. The deformable element is then driven by the eccentric. At a contact surface of the eccentric and the deformable element preferably only compressive forces and substantially no frictional forces act. A corresponding division of the eccentric into an inner area and a bearing ring is also possible if the eccentric is an outer rotor which is arranged around an (inner) housing. It is also possible, that is dispensed with the outer bearing ring and roll the rollers of the bearing directly on or on the deformable element.

Preferably, the pump has at least one drive for moving the eccentric. The drive is preferably an electric motor, which is connected to a (shaft extending along the axis) to the eccentric. The pump is preferably also adapted to be operated opposite to the conveying direction. For this purpose, the eccentric is rotated counter to the conveying direction. In such a pump, an angular distance between the inlet and the outlet in the circumferential direction about the axis can be determined, ie in particular the distance of the furthest apart opening regions of the inlet and the outlet via the inlet and the outlet. This angular distance is preferably limited by the respective outer (maximum spaced) areas of the inlet and the outlet. The angular distance can therefore also be referred to as the maximum angular distance of the inlet and the outlet or the cross-sectional areas of the inlet and the outlet. The angular separation may also be described by the angle of a circular arc segment which is sufficiently large to completely cover both the inlet and the outlet.

Furthermore, an angle section can also be determined which the seal spans in the circumferential direction and thereby closes the conveying path. In particular, this angle section therefore relates to a section between two adjacent closed pump volumes. In this case, the conveying path is closed in this angular section as a result of deformation of the deformable element. In the angular section of the conveying path, the conveying path has no (open) cross-sectional area. It is provided here that the angle section (amount) is greater than the angular distance. This leads in particular to the embodiment that, in the event that the (a) seal is centered between the inlet and the outlet is positioned, the most distant opening portions of the inlet and the outlet (both and simultaneously) are still securely closed by the seal. Thus (undesired or simultaneous) pressure effects can be reduced by the inflowing and / or the outflowing liquid. Likewise, the forces or energies for the operation of the pump (permanently) can be kept lower, as well as an undesirable shift in position of the seal due to pressure pulses and thus possibly accompanying irregularities in the spray pattern formation are significantly limited. In addition, the dosing accuracy is improved because undesired bypasses in the conveying path past the seal are reliably avoided even under wear, high load and aging considerations. Accordingly, it is preferred that the angle section is designed to be at least 5, in particular at least 8% and very preferably at least 12% larger than the angular distance. Depending on the number of seals in the conveying path of the pump, it makes sense for the angle section to be at most 120% larger than the angular distance so that a sufficiently large delivery volume (closed pump volume) can still be formed here.

The pump is particularly advantageous if the angular distance between the inlet and the outlet is less than 40 ° [angular degree]. It is preferred that this angular distance is less than 30 ° and in particular less than 25 °, wherein to ensure a sufficient cross section of the inlet and the outlet for use in the automotive sector, the angular distance should not fall below 18 ° (substantially). A special small angular distance enables a particularly compact pump with a particularly large flow rate, because less space is required for the inlet and the outlet and that at least one closed pump volume can be particularly large.

Furthermore, the pump is advantageous if the at least one inlet and the at least one outlet have an elongated cross-sectional area in the direction of the axis. Here, the cross-sectional area of inlet and outlet is meant directly at the gap between eccentric and pump housing. The cross-sectional area of the inlet or outlet is swept by the seal when the eccentric is rotated. The seal rolls off on the pump housing. An elongated cross-sectional area is preferably oval. By an elongated cross-sectional area in the axial direction, it is possible to reduce the expansion from the inlet and the outlet in the circumferential direction. This makes it possible to reduce the angular distance between the inlet and the outlet. Even if a "symmetrical" configuration of the cross-sectional areas of the inlet and the outlet is assumed here, it may nevertheless be useful in applications to design only cross-sectional areas of the inlet or the outlet, or both cross-sectional areas with a different shape the elongate cross-sectional area (eg different lengths, widths, curves, etc.).

Furthermore, the pump is advantageous if the spanned by the sealing angle portion is greater than 90 ° [angle degree].

By such a large angle section in which the seal is formed and the conveying path is closed, it is possible to carry out the pressure increase in the at least one closed pump volume or the compression of the at least one closed pump volume particularly effective. It is particularly advantageous if the spanned angle section is even greater than 120 °. In this case, the overstretched angle section, for example, should not exceed 180 °, because otherwise the at least one closed pump volume is too small and the delivery rate of the pump would decrease.

Furthermore, the pump is advantageous if the eccentric has a shape deviating from the circular shape, so that at least one of the following effects occurs by a displacement of the at least one seal in the conveying direction from the inlet to the outlet:

A closed pump volume in the delivery path is compressed. The deformable element is deformed so that an increase in pressure occurs in the closed pump volume.

For the formation of the seal with the aid of the eccentric, the outer shape of the eccentric is relevant. The shape of an eccentric can be described by means of a polar coordinate system in which the pole of the coordinate system lies on the axis of the eccentric. In this coordinate system, an eccentric has a changing radius. Conventional eccentrics for the pumps provided here are arranged circular and eccentric to the axis of the pump, so that an eccentric movement of a peripheral surface occurs by a rotation of the eccentric about the axis. Shown in the described polar coordinate system, the radius of such an eccentric changes over the circumference or in the manner of a sinusoid. The result is a flat area in which the radius of the eccentric is smaller than in a raised area. The smallest radii of the eccentric in the polar coordinate system predetermine a circular basic shape of the eccentric. The circular basic shape is a circle concentric with the axis, which has the smallest radius of the eccentric in the polar coordinate system. About this circular basic shape is the raised area over. With the raised area, the eccentric presses on the deformable element and thus creates the seal.

The eccentric with a non-circular shape may for example be oval or have a different shape from the circular shape. A non-circular eccentric can also be described by the fact that the radius of such an eccentric shown in the circumference in the polar coordinate system has a form deviating from a sinusoid. In such an eccentric, a raised area can make up a greater angle than a flat area. It is also possible for a rising flank of the raised area to be steeper in the conveying direction than a falling flank. In addition, several elevated and flat areas can be provided over the circumference. A non-circular eccentric can also be provided with a bearing which separates an outer bearing ring from an inner eccentric region. This bearing can be flexible and deformable rather than rigid and circular. The bearing then deforms during the rotation of the inner eccentric region in each case in accordance with the eccentric movement and transmits this movement to the deformable element.

The two effects described can occur individually or in combination with each other. If the pumped liquid is compressible or even (also) a gas is delivered instead of a liquid, then the closed pump volume in the delivery path is compressed. If the pumped fluid is incompressible, compression of the closed pump volume is not possible. Instead, the deformable element is then deformed and / or compressed. During compression, the deformable element is compressed. In a deformation, for example, areas of the deformable element can be elastically displaced. When pumping liquids and gases with low compressibility, both effects can occur in parallel. By compressing and / or increasing the pressure, pressure fluctuations during delivery are leveled out and delivery is made even.

Furthermore, the pump is advantageous if the pump housing has a shape deviating from the circular shape, so that by displacement of the at least one seal in the conveying direction from the inlet to the outlet at least one of the following effects occurs:

A closed pump volume is compressed in the delivery path. The deformable element is deformed such that a pressure increase occurs in the closed pump volume. Such a design of the pump housing may be an alternative to the above-described design of the eccentric. It is usually easier, the advantageous effects described by a design of the pump housing instead of using the design of the eccentric to achieve. This is due to the fact that the pump housing is fixed and, unlike the eccentric, does not rotate. As a result, for example, a deformable bearing ring, as described above, omitted.

The statements made for the eccentric deviating from the circular shape using a polar coordinate system can also be applied to a non-circular or a non-circular pump housing. In this case, a deviation from a basic shape in the area of the stationary seal is not taken into account here. For the question of whether it is a pump housing with a round shape or a non-circular shape, (in particular) only the area of the pump housing is decisive, which is located in the conveying direction between the inlet and the outlet. A possible indentation of the pump housing in the area of the stationary seal (contrary to the conveying direction between outlet and inlet) is not considered here.

It is also possible that both the eccentric and the pump housing have a shape deviating from the circular shape, so that at least one of the two described effects occurs by a displacement of the at least one seal in the conveying direction from the inlet to the outlet.

Furthermore, the pump is advantageous if at least the pump housing or the eccentric are designed so that an arcuate gap between the pump housing and the eccentric, in which the deformable element is arranged, continuously tapers in the conveying direction from the inlet to the outlet.

In describing the taper of the arcuate gap toward the outlet, it should be remembered that the eccentric is eccentric. The eccentricity is negligible in describing the taper of the gap. The gap is much more to be measured between the pump housing and the above-defined circular basic shape of the eccentric. The arcuate gap is a portion of an annular gap between the eccentric and the pump housing. In the conveying direction from the inlet to the outlet there is then always little space in the arcuate gap for the deformable element and the at least one pump volume, the further the at least one pump volume is displaced towards the outlet. As a result, an ever greater compression of the pump volume and / or always a greater deformation of the deformable element occur on the way to the outlet. Thus, the described effects of compressing the pump volume or increasing the pressure in the closed pump volume can be achieved particularly effectively.

Furthermore, the pump is advantageous when the pump housing at the inlet has a first radius and at the outlet has a second radius, wherein the first radius is smaller than the second radius and the first radius continuously merges into the second radius.

Such a design of the pump housing is a particularly simple variant to achieve a narrowing of the arcuate gap between the eccentric and the pump housing. The shape of the pump housing with a continuously decreasing radius can also be referred to as a (sectional) screw shape.

The described design of the pump housing and the described design of the eccentric are also applicable regardless of the design of the inlet and the outlet with the angular distance and the seal with the overstretched angle section. Expressly described herein are pumps in which the angle section is not greater than the angular distance, but in which the housing and / or the eccentric are designed such that when the at least one seal is displaced in the conveying direction from the inlet to the outlet at least one the following effects already described above occur:

A closed pump volume is compressed in the delivery path. The deformable element is deformed so that an increase in pressure occurs in the closed pump volume.

Furthermore, the pump is advantageous if at least one of the following components are designed such that during the displacement of the at least one seal from the inlet to the outlet s by the compression of the at least one closed pump volume or by the pressure increase, which occurs due to the deformation of the deformable element within the pump, there is a continuous adjustment of the pressure from the inlet to the outlet:

- the inlet,

the outlet,

the seal,

the pump housing,

the eccentric.

The inlet of the pump is usually connected to a suction line, through which the pump sucks liquid. The outlet of the pump is usually connected to a pressure line through which pressurized fluid leaves the pump. Preferably, as the fluid passes from the inlet to the outlet through the pump, the pressure is adjusted continuously from the pressure at the inlet to the pressure at the outlet. This is preferably achieved by at least one of the measures described above. A continuous adjustment of the pressure from the inlet to the outlet makes it possible to prevent unwanted pressure peaks and pressure fluctuations particularly effectively.

Further, a motor vehicle is proposed, comprising an internal combustion engine, an exhaust gas treatment device for cleaning the exhaust gases of the internal combustion engine and a device with a described pump, with which a liquid (in particular urea-water solution) for exhaust gas purification can be promoted in the exhaust gas treatment device. An addition device is preferably provided at the exhaust gas treatment device. hen, with which the pumped by the pump liquid for exhaust gas purification of the exhaust gas treatment device can be supplied. The adding device, the pump and a tank for storing the liquid are preferably connected to each other by a conduit. In the exhaust gas treatment device, an SCR catalytic converter is preferably provided, on which nitrogen oxide compounds in the exhaust gas of the internal combustion engine are reduced with the aid of the liquid for exhaust gas purification.

The invention and the technical environment will be explained in more detail with reference to FIGS. The figures show particularly preferred embodiments, to which the invention is not limited. In particular, it should be noted that the figures and in particular the magnitudes shown are only schematically. FIG. 1 shows a first embodiment of a described pump; FIG.

2 shows a second embodiment of a described pump;

3 is a diagram showing the operation of a pump of the state of

Technology clarifies;

4 shows a third embodiment variant of a described pump;

Fig. 5: a fourth embodiment of a described pump;

Fig. 6 is a diagram illustrating the operation of a described pump;

7 shows a fifth embodiment of a described pump;

Fig. 8 is a diagram illustrating the operation of the fifth embodiment of the described pump; Fig. 9 is an isometric view of a pump;

10 is an isometric view of another pump;

11 shows a cross section through a described pump;

FIG. 12 shows a sixth embodiment variant of a described pump; FIG. and FIG. 13 shows a motor vehicle having a described pump.

1, 2, 4, 5 and 7 show various embodiments of the described pump 1, which will be explained together with respect to the matching technical or functional features first together. The pump 1 has in each case a pump housing 2 in which an eccentric 5 rotatable about an axis 6 is arranged. In a gap 17 between the pump housing 2 and the eccentric 5 is in each case a (single and one-piece) deformable element 7. When the eccentric 5 is moved about the axis 6, the deformable element 7 rolls on the pump housing 2. In this case, a seal 9 is moved between the pump housing 2 and the deformable element 7 along a conveying direction 11. As a result, at least one pump volume 10 is displaced along a delivery path 8 from the inlet 3 to the outlet 4. This causes liquid with the conveying direction 11 to enter the pump housing 2 through the inlet 3 and exit the pump housing 2 through the outlet 4. The axis 6 specifies an axial direction of the pump 1. Perpendicular to this axis 6 is the radial direction 15. Perpendicular to the radial direction 15 in turn is the circumferential direction 12. Based on the circumferential direction 12, the position of the seals 9 can be defined. The pump 1 also has a stationary seal 29, which prevents backflow of liquid against the conveying direction 11 from the outlet 4 to the inlet 3. According to FIGS. 1, 4 and 5, this seal is in each case as Dentation 30 of the housing 2 between the inlet 3 and the outlet 4 executed. In the embodiment variants in FIGS. 2 and 7, the stationary seal 29 is produced in each case with a pin 31 which is inserted into the deformable element 7. In a further embodiment variant of the stationary seal 29 (not illustrated here), the deformable element 7 can be attached to the pump housing 2 in a liquid-tight manner. For example, the deformable element 7 may be jammed or glued.

According to all embodiments of the pump 1 in FIGS. 1, 2, 4, 5 and 7, the eccentric 5 has a bearing 28. In the embodiment variants in FIGS. 1 and 2, the eccentric 5 is divided by the bearing 28 into an inner region 41 and into an outer bearing ring 42. In the embodiment variants in FIGS. 4, 5 and 7, there is no outer bearing ring, but the bearing 28 rolls off directly on the deformable element 7. If the eccentric has a non-circular (deviating from the circular shape) form, the bearing 28 and possibly also the outer bearing ring 42 should be deformable. The bearing 28 and the outer bearing ring 42 are then respectively driven according to the eccentricity of the eccentric 5.

According to all embodiments shown in FIGS. 1, 2, 4, 5 and 7, the deformable element 7 is designed in each case as a deformable membrane 21.

1 and 2, an angular portion 14 is shown, in which the deformable element 7 forms the displaceable seal 9 together with the pump housing 2. In addition, an angular distance 13 is shown, which exists between the outlet 4 and the inlet 3 of the pump 1.

In FIGS. 4 and 5, the same embodiment of a pump 1 is shown in each case, the position of the eccentric 5 and the seal 9 in the pump housing 2 being different in the two representations. In this embodiment variant of the pump 1, the pump housing 2 is designed so that the gap 17 tapers continuously between a circular basic shape 45 of the eccentric 5 and the pump housing 2 towards the outlet 4. The pumping Housing 2 has a continuously decreasing from the inlet 3 to the outlet 4 radius. In the region of the inlet 3, the pump housing 2 has a first radius 18. This goes continuously into a second radius 19 of the pump housing 2 at the outlet 4. As a result, a closed pump volume 10 is compressed during the displacement of the seal 9 from the inlet 3 to the outlet 4 and / or the deformable element 7 deforms such that a pressure increase occurs in the closed pump volume 10.

By way of illustration, FIGS. 4 and 5 show a delivery of a complex medium. The occurring effects in the promotion of an incompressible liquid would not be represented in a drawing, because in an incompressible liquid by a pressure increase no change in the pump volume 10 would occur. FIG. 4 shows a situation in which the seal 9 of the pump 1 is arranged in the vicinity of the inlet 3 and a pump volume 10 is arranged in the vicinity of the outlet 4. A channel cross section 43 of the delivery path 8 in the pump volume 10 can also be seen. FIG. 5 shows a situation in which a seal 9 is arranged in the vicinity of the outlet 4 of the pump 1. It can be seen that a pump volume 10 is then located near the inlet 3. The pump volume 10 also has a channel cross-sectional area 43 there. It can be seen that the channel cross-section 43 in FIG. 5 is larger than the channel cross-section 43 in FIG. 4. The pump volume 10 thus becomes on the way from the inlet 3 to the outlet 4 compressed. When the pump 1 conveys a non-compressible liquid, this compression effect can not occur. Then, the volume of the movable pump volume (and substantially also the cross-section of the pump volume 10) remains constant over the entire path from the inlet 3 to the outlet 4. However, then occurs in the deformable element 7 to the outlet 4 to an increasing deformation. This stronger deformation of the deformable element 7 causes a pressure increase in the pump volume 10. Fig. 7 shows an embodiment of a pump 1, with an eccentric 5 with a non-round (deviating from the circular shape). This eccentric 5 has a first diameter 32 and a second diameter 33 perpendicular thereto. The second diameter 33 is smaller than the first diameter 32, so that the eccentric 5 is not circular.

FIGS. 3 and 6 illustrate the operation of a described pump. In Fig. 3 is shown as a basis for comparison, the operation of a pump in which there is neither a corresponding ratio of angular distance and angle section, nor a corresponding design of the eccentric or the pump housing have been made. In FIGS. 3 and 6, the structure of the pump has been transferred from a polar coordinate system with the radial direction 15 and the circumferential direction 12 into a Cartesian coordinate system. For a better understanding, the radial direction 15 and the circumferential direction 12 in the figures 3 and 6 are also shown. In both figures, the pump housing 2 with the inlet 3 and the outlet 4, the eccentric 5 and the deformable element 7 and the conveying path 8 with the at least one pump volume 10 and the at least one seal 9 are shown. Furthermore, the stationary seal 29 can be seen, which can be seen in each case at both ends of the wound-up representation of the pump 1 in FIG. The two portions of the stationary seal 29 shown separately in Figs. 3 and 6 are in fact one (single) stationary seal 29. If the Cartesian representation in Figs. 3 and 6 were again transferred back to polar coordinates, the two stationary seals would be separately shown 29 to each other or each other. The eccentric 5 each has a circular basic shape 45 and elevated area

34 and a flat portion 35. The raised portion 34 and the flat portion

35 are shown simplified in each case stepped with flattened edges. In fact, there is more of a sinusoidal shape forming the raised portion 34 and the flat portion 35. The steps a) to e) each show five different positions of the eccentric 5, wherein the eccentric 5 is moved from step to step in the conveying direction 11 on. It can be seen in FIG. 3 that the channel cross section 43 of the pump volume 10 increases as soon as a connection between the outlet 4 and the pump volume 10 occurs. This is due to the fact that an increased pressure is applied to the outlet 4, and therefore liquid flows through the outlet 4 into the pump volume 10 as soon as a connection exists between the pump volume 10 and the outlet 4. Finally, when the seal 9 is moved further and the pump volume 10 is reduced in total, the liquid previously flowed into the pump volume 10 through the outlet 4 is again expelled from the outlet 4. In the pump shown in FIG. 3, no measures are provided which enable compression or an increase in pressure in the at least one closed pump volume 8 on the way from the inlet 3 to the outlet 4.

The pump housing 2 according to FIG. 6 has a first larger radius 18 at the inlet 3 and a second smaller radius 19 at the outlet 4. This manifests itself in the form of a chamfer 44 of the pump housing 2 towards the outlet 4. A gap 17 between the pump housing 2 and a circular basic shape 45 of the eccentric 5 tapers towards the outlet 4. It can be seen that the bevel 44 causes an increasing deformation of the deformable element 7 on the way to the outlet 4. This increasing deformation ensures that the pressure in the pump volume 10 increases and is equalized to the pressure applied to the outlet 4. If there is a liquid-conducting connection between the outlet 4 and the pump volume 10 (see step d), the pressure in the pump volume has preferably increased to such an extent that this pressure corresponds to the pressure at the outlet 4.

FIG. 8 shows a representation of the embodiment of the pump 1 corresponding to FIGS. 3 and 6, which is shown in FIG. It can be seen here that the Ex- 5 in sections (in particular in the flat region 35) has an asymmetrical shape 36, which is characterized in that a lying in the conveying direction 11 before the respective pump volume 10 flank of the eccentric 5 has a different shape than one in the conveying direction behind the respective pump volume 10th As a result, compression and / or the liquid in the at least one pump volume 10 on the way from the inlet 3 to the outlet 4 can be achieved.

9 and 10 show two different isometric views of a pump 1. Shown are respectively the axis 6, the radial direction 15 and the circumferential direction 12. Along the axis 6 above the pump housing 2, a drive 26 of the pump is arranged, which via a Drive shaft 27 is connected to the eccentric 5, not shown here, in the pump housing 2. The inlet 3 and the outlet 4 of the pump housing 2, each having a cross-sectional area 16, can be seen in each case. In the embodiment variant shown in FIG. 9, the inlet 3 and the outlet 4 are each circular. In the embodiment shown in Fig. 10, the inlet 3 and the outlet 4 are each elongated (similar to a slot) designed so that they have an elongated cross-sectional area 16 in the direction of the axis 6. This makes it possible to design the angular distance 13 shown in FIG. 10 for a given cross-sectional area 16 of inlet 3 and outlet 4 to be particularly small.

Fig. 11 shows a cross section through a pump 1, as shown for example in Figs. 1, 2, 4, 5 and 7. Evident are the pump housing 2, the eccentric 5, the axis 6, the drive 26 and the drive shaft 27 and designed as a diaphragm 21 deformable element 7, which can be deformed by a movement of the eccentric 5 so that a seal, not shown here moves along the conveying path 8. The pump volume 10 is in each case arranged between the pump housing 2 and the deformable element 7. Fig. 12 shows a variant of a pump 1 with a hose 20 as a deformable element 7, which is arranged in a pump housing 2 between the pump housing 2 and the eccentric 5. The eccentric 5 is rotatably arranged along an axis 6 and compresses the hose 20 in sections with the aid of the housing 2, so that according to FIG. 12 two seals 9 are formed. By a rotation of the eccentric 5, the seals 9 are displaced in the conveying direction 11, so that the at least one pump volume 10 is displaced towards the outlet 4. By a suitable design of the eccentric 5 or the pump housing 2, even in such a pump 1, a homogenization of the discharge of liquid from the outlet 4 can be achieved.

13 shows a motor vehicle 22 comprising an internal combustion engine 23 and an exhaust gas treatment device 24 for cleaning the exhaust gases of the combustion engine 23. In the exhaust gas treatment device 24, an SCR catalytic converter 40 is provided, and the exhaust gas treatment device 24 can be a liquid additive with a device 25 be fed to the exhaust gas purification. The device 25 comprises a tank 37 for storing the liquid additive and injection devices 39 for adding the liquid additive to the exhaust gas treatment device 24. The injectors 39 are connected to the tank 37 via a line 38. On the line 38 and the pump 1 is arranged, with which the liquid additive can be promoted. The injection device 39 may comprise a nozzle, with which the liquid additive in the exhaust gas treatment device 24 is atomized and / or a metering valve, with which a metered delivery of the liquid additive can take place.

As a precaution, it should be noted that the combinations of technical features shown in the figures are not generally mandatory. Thus, technical features of a figure can be combined with other technical features of a further figure and / or the general description. Something else should apply only if the combination of features explicitly and / or the person skilled in the art realizes that otherwise the basic functions of the device can no longer be met.

LIST OF REFERENCE NUMBERS

pump

pump housing

Einlas s

outlet

eccentric

axis

deformable element

conveying

sliding seal

pump volume

conveying direction

circumferentially

angular distance

angle section

radial direction

Cross sectional area

gap

first radius

second radius

tube

deformable membrane

Power vehicle

Internal combustion engine

Exhaust treatment device

contraption

drive

drive shaft

camp

stationary seal

Eindelluns 31 pen

32 first diameter

33 second diameter

34 increased range

35 flat area

36 asymmetric shape

37 tank

38 line

39 injection device

40 SCR catalyst

41 inner area

42 outer bearing ring

43 channel cross section

44 bevel

45 circular basic shape

Claims

Patent claims

Pump (1) for conveying a liquid, comprising a pump housing (2) with at least one inlet (3) and at least one outlet (4), an eccentric (5) being arranged on the pump housing (2), which has an axis (6) can be rotated relative to the pump housing (2), and a deformable element (7) is arranged between the pump housing (2) and the eccentric (5), with at least one conveying path (8) being connected to the deformable element (7). from the at least one inlet (3) to the at least one outlet (4) and at least one displaceable seal (9) of the conveying path (8) is formed, which separates at least one closed pump volume (10) in the conveying path (8), wherein the at least one displaceable seal (9) can be displaced by a movement of the eccentric (5) to convey the liquid along the conveying path (8) in a conveying direction (11) from the inlet (3) to the outlet (4), wherein the The inlet (3) and the outlet (4) have an angular distance (13) from one another in the circumferential direction (12) around the axis (6) and the seal (9) spans an angular section (14) in the circumferential direction (12) in which the Conveying path (8) is closed, the angular section (14) being larger than the angular distance (13).

Pump (1) according to claim 1, wherein the deformable element (7) is a hose (20) which is inserted into an arcuate gap (17) between the eccentric (5) and the pump housing

(2) is inserted and connects the inlet (3) to the outlet (4).

Pump (1) according to claim 1, wherein the deformable element (7) is a deformable membrane (21) and the delivery path (8) from the at least one inlet

(3) to which at least one outlet (4) is at least partially limited by the pump housing (2) and the deformable membrane (21).

4. Pump (1) according to one of the preceding claims, wherein the angular distance (13) between the inlet (3) and the outlet (4) is less than 40°.

Pump (1) according to one of the preceding claims, wherein the at least one inlet (3) and the at least one outlet (4) in the direction of the axis

(6) have an elongated cross-sectional area (16).

Pump (1) according to one of the preceding claims, wherein the angular section (14) spanned by the seal (9) is greater than 90°.

Pump (1) according to one of the preceding claims, wherein the eccentric (5) has a shape that deviates from the circular shape, so that by moving the at least one seal (9) in the conveying direction (11) from the inlet (3) to the outlet (4) at least one of the following effects occurs:

a closed pump volume (10) in the delivery path (8) is compressed, and

the deformable element

(7) is deformed in such a way that a pressure increase occurs in the closed pump volume (10).

Pump (1) according to one of the preceding claims, wherein the pump housing (2) has a shape that deviates from the circular shape, so that by moving the at least one seal (9) in the conveying direction (11) from the inlet (3) to the outlet (4) at least one of the following effects occurs:

a closed pump volume (10) in the delivery path

(8) is compressed, and

the deformable element (7) is deformed so that a pressure increase occurs in the closed pump volume (10).

9. Pump (1) according to claim 7 or 8, wherein at least the pump housing (2) or the eccentric (5) are designed so that there is an arcuate gap (17) between the pump housing (2) and the eccentric (5), in which the deformable element (7) is arranged, tapers continuously in the conveying direction (11) from the inlet (3) to the outlet (4).

10. Pump (1) according to claim 9, wherein the pump housing has a first radius (18) at the inlet (3) and a second radius (19) at the outlet (4), the first radius (18) being larger than the second Radius (19) and the first radius (18) continuously merges into the second radius (19).

11. Pump (1) according to one of the preceding claims, wherein at least one of the following components are designed so that during the displacement of the at least one seal (9) from the inlet (3) to the outlet (4) by the compression of the at least a closed one

Pump volume (10) or due to the increase in pressure that occurs due to the deformation of the deformable element (7), a continuous adjustment of the pressure from the inlet (3) to the outlet (4) takes place within the pump (1):

- the inlet (3),

the outlet (4),

the seal (9),

the pump housing (2), and

the eccentric (5).

12. Motor vehicle (22) comprising an internal combustion engine (23), an exhaust gas treatment device (24) for cleaning the exhaust gases of the internal combustion engine (23) and a device (25) with a pump (1) according to one of the preceding claims, with which a liquid can be conveyed into the exhaust gas treatment device (24) for exhaust gas purification.