DE102013106170A1 - Pump for conveying a liquid - Google Patents

Abstract

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

Description

The invention relates to a pump for conveying a liquid which is particularly suitable for conveying a liquid additive into the exhaust gas device of an internal combustion engine.

For cleaning the exhaust gases of internal combustion engines exhaust treatment devices are known, in which a liquid additive is supplied to clean the exhaust gases. An exhaust gas purification process performed 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 commercially 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 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, wherein the deformable element is delimited by at least one feed path from the at least one inlet to the at least one outlet and at least one displaceable seal of the conveying path is formed, which in the conveying path is at least one closed one Separates pump volume and is displaceable by moving the eccentric for conveying the liquid along the conveying path in a conveying direction from the inlet to the outlet. 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 has no cross-sectional area, 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 displaced from the inlet to the outlet to convey 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, a closed pump volume is closed (only) on one side (downstream) by a seal and connected upstream with the inlet, so that the liquid can flow through the inlet into 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 into the pump housing or into 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 Pressed eccentric to 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 in sections U-shaped around the pump housing around and glued to the pump housing and / or pressed.

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 to prevent 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. With a bypass It 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.

In principle, the stationary seal can also be achieved in that the deformable membrane in the region of the stationary seal is attached to the pump housing in a fluid-tight manner (for example screwed and / or adhesively bonded). 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 in an inner region 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 removal 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 the conveying path closes. In particular, therefore, this angle section 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 results in particular in the configuration that, in the case where the seal (s) is positioned midway between the inlet and the outlet, the most distal opening portions of the inlet and outlet (both and simultaneously) are still securely closed by the seal are. 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 unwanted bypasses are safely avoided in the conveying path to the seal over, even under wear, high load and aging considerations. Accordingly, it is preferred that the angle section is made at least 5%, in particular at least 8%, and more 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 that the angle section is greater than the angular distance by a maximum of 120%, so that here still a sufficiently large delivery volume (closed pump volume) can be formed.

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 elongate 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. Although it is assumed that a "symmetrical" design of the cross-sectional areas of the inlet and the outlet, it may nevertheless be useful in applications to design only cross-sectional areas of the inlet or the outlet accordingly, or both cross-sectional areas with a different expression of the elongated Cross-sectional area (eg different lengths, widths, curvatures, etc.) to make.

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.

• – Ein geschlossenes Pumpenvolumen in dem Förderweg wird komprimiert.
• – Das verformbare Element wird so verformt, dass ein Druckanstieg in dem geschlossenen Pumpenvolumen auftritt.

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 conveying path is compressed.
• - The deformable element is deformed so that a pressure increase occurs in the closed pump volume.

For the formation of the seal by means 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 one 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 radius of the eccentric in the polar coordinate system predetermines 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 pushes 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 upon rotation of the inner eccentric each according to 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.

• – Ein geschlossenes Pumpenvolumen wird in dem Förderweg komprimiert
• – Das verformbare Element wird so verformt, dass ein Druckanstieg in dem geschlossenen Pumpenvolumen auftritt.

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 conveying path
• - The deformable element is deformed so 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 to achieve the advantageous effects described by a design of the pump housing instead of using the design of the eccentric. 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 by a displacement of the at least one seal in Delivery direction from the inlet to the outlet of at least one of the two effects described occurs.

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 rather 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 then there is 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.

• – Ein geschlossenes Pumpenvolumen wird in dem Förderweg komprimiert.
• – Das verformbare Element wird so verformt, dass ein Druckanstieg in dem geschlossenen Pumpenvolumen auftritt.

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 spanned 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 conveying path.
• - The deformable element is deformed so that a pressure increase occurs in the closed pump volume.

• – der Einlass,
• – der Auslass,
• – die Abdichtung,
• – das Pumpengehäuse,
• – der Exzenter.

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 by the compression of the at least one closed pump volume or by the pressure increase that occurs due to the deformation of the deformable element, Within the pump, a continuous adjustment of the pressure from the inlet to the outlet takes place:

• - 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 pump described, with which a liquid (in particular urea-water solution) for exhaust gas purification can be promoted in the exhaust gas treatment device. At the exhaust gas treatment device, preferably, an adding device is provided with which the liquid conveyed by the pump can be supplied to the exhaust gas treatment device for exhaust gas purification. The adding device, the pump and a tank for storing the liquid are preferably connected to each other by a conduit. Preferably, in the exhaust gas treatment device, an SCR catalyst is 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 illustrated proportions are only schematic. Show it:

1 a first embodiment of a described pump;

2 a second embodiment of a described pump;

3 a diagram illustrating the operation of a pump of the prior art;

4 a third embodiment of a described pump;

5 a fourth embodiment of a described pump;

6 a diagram illustrating the operation of a described pump;

7 a fifth embodiment of a described pump;

8th a diagram illustrating the operation of the fifth embodiment of the pump described;

9 : an isometric view of a pump;

10 an isometric view of another pump;

11 a cross section through a described pump;

12 a sixth embodiment of a described pump; and

13 : A motor vehicle, comprising a described pump.

The 1 . 2 . 4 . 5 and 7 show various embodiments of the described pump 1 , which are to be explained together with regard to the matching technical or functional features. The pump 1 each has a pump housing 2 on, in which one around an axis 6 rotatable eccentric 5 is arranged. In a gap 17 between the pump housing 2 and the eccentric 5 there is one (single and one piece) deformable element 7 , If the eccentric 5 around the axis 6 is moved, rolls the deformable element 7 on the pump housing 2 from. This is a seal 9 between the pump housing 2 and the deformable element 7 along a conveying direction 11 emotional. As a result, at least one pump volume 10 along a conveyor route 8th from the inlet 3 to the outlet 4 postponed. This causes fluid with the conveying direction 11 through the inlet 3 into the pump housing 2 enters and through the outlet 4 from the pump housing 2 exit. The axis 6 gives an axial direction of the pump 1 in front. Perpendicular to this axis 6 is the radial direction 15 , Perpendicular to the radial direction 15 again stands the circumferential direction 12 , Based on the circumferential direction 12 can change the position of the seals 9 To be defined.

The pump 1 also has a stationary seal 29 on, the backflow of liquid counter to the conveying direction 11 from the outlet 4 to the inlet 3 prevented. According to the 1 . 4 and 5 this seal is each as a dent 30 of the housing 2 between the inlet 3 and the outlet 4 executed. In the embodiments in 2 and 7 is the stationary seal 29 each with a pen 31 generated, which in the deformable element 7 is used. In a further embodiment of the stationary seal not shown here 29 can be the deformable element 7 on the pump housing 2 be attached liquid-tight. For example, the deformable element 7 be stuck or glued.

According to all variants of the pump 1 in the 1 . 2 . 4 . 5 and 7 indicates the eccentric 5 a warehouse 28 on. In the embodiments in the 1 and 2 is the eccentric 5 through the camp 28 in an inner area 41 and in an outer bearing ring 42 divided up. In the embodiments in the 4 . 5 and 7 There is no outer bearing ring but the bearing 28 rolls directly on the deformable element 7 from. If the eccentric has a non-round (deviating from the circular shape), the camp should 28 and possibly also the outer bearing ring 42 be deformable. The warehouse 28 and the outer bearing ring 42 then each corresponding to the eccentricity of the eccentric 5 fulled.

According to all in the 1 . 2 . 4 . 5 and 7 illustrated embodiments is the deformable element 7 each as a deformable membrane 21 executed.

In the 1 and 2 is an angle section 14 shown in which the deformable element 7 together with the pump housing 2 the sliding seal 9 formed. In addition, an angular distance 13 shown between the outlet 4 and the inlet 3 the pump 1 exist.

In the 4 and 5 is in each case the same embodiment of a pump 1 represented, wherein in the two representations, the position of the eccentric 5 and the seal 9 in the pump housing 2 is different. In this embodiment of the pump 1 is the pump housing 2 designed so that the gap 17 between a circular basic shape 45 of the eccentric 5 and the pump housing 2 to the outlet 4 continuously rejuvenated. The pump housing 2 has one from the inlet 3 to the outlet 4 continuously decreasing radius. In the area of the inlet 3 has the pump housing 2 a first radius 18 , This goes continuously into a second radius 19 of the pump housing 2 at the outlet 4 above. This will create a closed pump volume 10 during the displacement of the seal 9 from the inlet 3 to the outlet 4 compressed and / or the deformable element 7 deforms so that a pressure increase in the closed pump volume 10 occurs.

For illustration is in the 4 and 5 shown a promotion of a compressible medium. The effects occurring in the promotion of an incompressible liquid would not be shown in a drawing, because in an incompressible liquid by increasing the pressure no change in the pump volume 10 would occur. In the 4 is to recognize a situation in which the seal 9 the pump 1 near the inlet 3 is arranged and a pump volume 10 near the outlet 4 is arranged. You can also see a channel cross-section 43 of the transport route 8th in the pump volume 10 , In 5 a situation is shown in which a seal 9 near the outlet 4 the pump 1 is arranged. It can be seen that then close to the inlet 3 a pump volume 10 located. The pump volume 10 also has a channel cross-sectional area there 43 , It can be seen that the channel cross section 43 in 5 is greater than the channel cross-section 43 in 4 , The pump volume 10 So will be on the way from the inlet 3 to the outlet 4 compressed. If with the pump 1 a non-compressible liquid is delivered, this compression effect can not occur. Then the volume of the movable pump volume (and essentially also the cross section of the pump volume) remains 10 ) all the way from the inlet 3 to the outlet 4 constant. However, then occurs in the deformable element 7 to the outlet 4 an increasing deformation. This stronger deformation of the deformable element 7 causes an increase in pressure in the pump volume 10 ,

7 shows an embodiment of a pump 1 , with an eccentric 5 with a non-circular (deviating from the circular shape) form. This eccentric 5 has a first diameter 32 and a second diameter perpendicular thereto 33 , The second diameter 33 is smaller than the first diameter 32 so that the eccentric 5 is not circular.

The 3 and 6 illustrate the operation of a described pump. In 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 the 3 and 6 is the construction of the pump from a polar coordinate system with the radial direction 15 and the circumferential direction 12 transferred into a Cartesian coordinate system. For better understanding, the radial direction 15 and the circumferential direction 12 in the 3 and 6 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 as well as the funding route 8th with the at least one pump volume 10 and the at least one seal 9 shown. Furthermore, the stationary seal 29 to recognize that in the 3 in each case at both ends of the wound-up representation of the pump 1 can be seen. The two in 3 and 6 separated sections of the stationary seal 29 are actually a (single) stationary seal 29 , If the Cartesian representation in 3 and 6 would be transferred back into polar coordinates, would be the two stationary seals shown separately 29 to each other or each other. The eccentric 5 each has a circular basic shape 45 and elevated area 34 as well as a flat area 35 , The raised area 34 and the flat area 35 Here are simplified each shown stepped with flattened edges. In fact, here is more of a sinusoidal waveform, which is the elevated area 34 and the flat area 35 forms.

The steps a) to e) each show five different positions of the eccentric 5 , where the eccentric 5 from step to step in conveying direction 11 is moved further.

In 3 it can be seen that the channel cross-section 43 the pump volume 10 increases as soon as a connection between the outlet 4 and the pump volume 10 occurs. This is because at the outlet 4 an increased pressure is applied, and therefore liquid through the outlet 4 into the pump volume 10 flows in as soon as a connection between the pump volume 10 and the outlet 4 exist. When finally the seal 9 is moved further and the pump volume 10 Total shrinking, then the previously in the pump volume 10 through the outlet 4 has flowed Liquid back from the outlet 4 ejected. At the in 3 Pump provided are no measures provided that a compression or an increase in pressure in the at least one closed pump volume 8th on the way from the inlet 3 to the outlet 4 enable.

The pump housing 2 according to 6 has a first larger radius 18 at the inlet 3 and a second smaller radius 19 at the outlet 4 , This is in the form of a chamfer 44 of the pump housing 2 to the outlet 4 noticeable. 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 by the bevel 44 an increasing deformation of the deformable element 7 on the way to the outlet 4 occurs. This increasing deformation ensures that the pressure in the pump volume 10 rises and at the outlet 4 applied pressure is adjusted. If 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 so much that this pressure is equal to the pressure at the outlet 4 equivalent.

8th shows a the 3 and 6 corresponding representation of the embodiment of the pump 1 , in the 7 is shown. Here it can be seen that the eccentric 5 in sections (especially in the flat area 35 ) an asymmetrical shape 36 has, which is characterized in that one in the conveying direction 11 before the respective pump volume 10 lying flank of the eccentric 5 has a different shape than one in the conveying direction behind the respective pump volume 10 lying flank of the eccentric 5 , This can also be a compression and / or the liquid in the at least one pump volume 10 on the way from the inlet 3 to the outlet 4 be achieved.

The 9 and 10 show two different isometric views of a pump 1 , The axis is shown in each case 6 , the radial direction 15 and the circumferential direction 12 , Along the axis 6 above the pump housing 2 is a drive 26 arranged the pump, which via a drive shaft 27 with the eccentric, not shown here 5 in the pump housing 2 connected is. The inlet can be seen in each case 3 and the outlet 4 of the pump housing 2 each having a cross-sectional area 16 exhibit. At the in 9 illustrated embodiment, the inlet 3 and the outlet 4 each circular. At the in 10 illustrated embodiment, the inlet 3 and the outlet 4 each elongated (similar to a slot) designed so that they are in the direction of the axis 6 an elongated cross-sectional area 16 exhibit. This allows the in 10 illustrated angular distance 13 for a given cross-sectional area 16 from inlet 3 and outlet 4 especially small.

11 shows a cross section through a pump 1 , as in the example 1 . 2 . 4 . 5 and 7 is shown. The pump housing can be seen 2 , the eccentric 5 , the axis 6 , the drive 26 and the drive shaft 27 as well as the membrane 21 executed deformable element 7 , which is caused by a movement of the eccentric 5 can be deformed so that a seal not shown here along the conveying path 8th emotional. The pump volume 10 is in each case between the pump housing 2 and the deformable element 7 arranged.

12 shows an embodiment of a pump 1 with a hose 20 as a deformable element 7 which is in a pump housing 2 between the pump housing 2 and the eccentric 5 is arranged. The eccentric 5 is along an axis 6 rotatably arranged and presses the hose 20 with the help of the housing 2 in sections, so that according to 12 two seals 9 are formed. By a rotation of the eccentric 5 become the seals 9 in the conveying direction 11 shifted so that the at least one pump volume 10 to the outlet 4 is moved. By a suitable design of the eccentric 5 or the pump housing 2 can also with such a pump 1 an equalization of the discharge of liquid from the outlet 4 be achieved.

13 shows a motor vehicle 22 comprising an internal combustion engine 23 and an exhaust treatment device 24 for cleaning the exhaust gases of the internal combustion engine 23 , In the exhaust treatment device 24 is an SCR catalyst 40 provided and the exhaust treatment device 24 can with a device 25 a liquid additive for exhaust gas purification are supplied. The device 25 includes a tank 37 for storing the liquid additive and injectors 39 for adding the liquid additive to the exhaust treatment device 24 on. Injectors 39 are with the tank 37 over a line 38 connected. On the line 38 is also the pump 1 arranged, with which the liquid additive can be promoted. The injector 39 may include a nozzle with which the liquid additive in the exhaust 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 another figure and / or the general description. Something else should only apply if the combination of features was explicitly identified here and / or the person skilled in the art recognizes that otherwise the basic functions of the device can no longer be met.

LIST OF REFERENCE NUMBERS

1

 pump

2

 pump housing

3

 inlet

4

 outlet

5

 eccentric

6

 axis

7

 deformable element

8th

 conveying

9

 sliding seal

10

 pump volume

11

 conveying direction

12

 circumferentially

13

 angular distance

14

 angle section

15

 radial direction

16

 Cross sectional area

17

 gap

18

 first radius

19

 second radius

20

 tube

21

 deformable membrane

22

 motor vehicle

23

 Internal combustion engine

24

 Exhaust treatment device

25

 contraption

26

 drive

27

 drive shaft

28

 camp

29

 stationary seal

30

 denting

31

 pen

32

 first diameter

33

 second diameter

34

 increased area

35

 flat area

36

 unbalanced shape

37

 tank

38

 management

39

 Injector

40

 SCR catalyst

41

 inner area

42

 outer bearing ring

43

 Channel cross section

44

 bevel

45

 circular basic shape

Claims (12)

Pump ( 1 ) for conveying a liquid, comprising a pump housing ( 2 ) with at least one inlet ( 3 ) and at least one outlet ( 4 ), wherein on the pump housing ( 2 ) an eccentric ( 5 ) arranged with an axis ( 6 ) relative to the pump housing ( 2 ) is rotatable, and wherein between the pump housing ( 2 ) and the eccentric ( 5 ) a deformable element ( 7 ), wherein with the deformable element ( 7 ) at least one funding route ( 8th ) from the at least one inlet ( 3 ) to the at least one outlet ( 4 ) is limited and at least one sliding seal ( 9 ) of the transport route ( 8th ) formed in the conveying path ( 8th ) at least one closed pump volume ( 10 ), wherein the at least one displaceable seal ( 9 ) by a movement of the eccentric ( 5 ) for conveying the liquid along the conveying path ( 8th ) in a conveying direction ( 11 ) from the inlet ( 3 ) to the outlet ( 4 ) is displaceable, wherein the inlet ( 3 ) and the outlet ( 4 ) in the circumferential direction ( 12 ) around the axis ( 6 ) an angular distance ( 13 ) and the seal ( 9 ) in the circumferential direction ( 12 ) an angle section ( 14 ), in which the conveying path ( 8th ) is closed, wherein the angle section ( 14 ) greater than the angular distance ( 13 ). Pump ( 1 ) according to claim 1, wherein the deformable element ( 7 ) a hose ( 20 ), which is in an arcuate gap ( 17 ) between the eccentric ( 5 ) and the pump housing ( 2 ) and the inlet ( 3 ) with the outlet ( 4 ) connects. Pump ( 1 ) according to claim 1, wherein the deformable element ( 7 ) a deformable membrane ( 21 ) and the funding path ( 8th ) from the at least one inlet ( 3 ) to the at least one outlet ( 4 ) from the pump housing ( 2 ) and the deformable membrane ( 21 ) is at least partially limited. 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 ) one in the direction of the axis ( 6 ) elongated cross-sectional area ( 16 ) exhibit. Pump ( 1 ) according to any one of the preceding claims, wherein the seal ( 9 ) spanned angle section ( 14 ) is greater than 90 °. Pump ( 1 ) according to one of the preceding claims, wherein the eccentric ( 5 ) has a different shape from the circular shape, so that by a displacement of 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 funding path ( 8th ) is compressed, and - the deformable element ( 7 ) is deformed such that a pressure increase in the closed pump volume ( 10 ) occurs. Pump ( 1 ) according to any one of the preceding claims, wherein the pump housing ( 2 ) has a different shape from the circular shape, so that by a displacement of 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 funding path ( 8th ) is compressed, and - the deformable element ( 7 ) is deformed such that a pressure increase in the closed pump volume ( 10 ) occurs. Pump ( 1 ) according to claim 7 or 8, wherein at least the pump housing ( 2 ) or the eccentric ( 5 ) are designed so that an arcuate gap ( 17 ) between the pump housing ( 2 ) and the eccentric ( 5 ), in which the deformable element ( 7 ) is arranged, in the conveying direction ( 11 ) from the inlet ( 3 ) to the outlet ( 4 ) continuously rejuvenated. Pump ( 1 ) according to claim 9, wherein the pump housing at the inlet ( 3 ) a first radius ( 18 ) and at the outlet ( 4 ) a second radius ( 19 ), where the first radius ( 18 ) is greater than the second radius ( 19 ) and the first radius ( 18 ) continuously into the second radius ( 19 ) passes over. 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 one closed pump volume ( 10 ) or by the pressure increase caused by the deformation of the deformable element ( 7 ) occurs within the pump ( 1 ) a continuous adjustment of the pressure from the inlet ( 3 ) to the outlet ( 4 ): - the inlet ( 3 ), - the outlet ( 4 ), - the sealing ( 9 ), - the pump housing ( 2 ), and - the eccentric ( 5 ). Motor vehicle ( 22 ) comprising an internal combustion engine ( 23 ), an exhaust 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 for exhaust gas purification in the exhaust gas treatment device ( 24 ).

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