DE102022202277A1 - Pump, pump system and water-bearing household appliance - Google Patents

Abstract

A pump (1) is provided for a water-carrying household appliance (100). The pump (1) comprises a shaft (2) which extends in an axial direction (A), a bearing bush (3) which is designed to support the shaft (2) so that it can rotate about the axial direction (A), a drive (4) designed to drive the shaft (2) in rotation, and a seal (5) designed to seal against the shaft (2). The seal (5) is arranged in a sealing area (6) of the shaft (2) and the drive (4) is arranged in an opposite drive area (7) of the shaft (2) with respect to the bearing bush (3). The bearing bush (3) has at least one passage (8) which is designed to bring the sealing area (6) into communication with the drive area (7). A pump system and a water-carrying household appliance are also provided.

Description

The invention relates to a pump, a pump system for a water-bearing household appliance and a water-bearing household appliance.

Lye pumps are usually used in laundry treatment appliances in order to pump a fluid, such as a lye or liquor, out or around. In terms of drive technology, such drain pumps are often designed according to the wet rotor principle, so that a generally magnetic rotor of the pump or a pump drive is arranged in the fluid to be pumped. With this constructive drive concept (wet runner), cost-intensive mechanical seals with increased friction, which separate the working medium from the drive, can be dispensed with. A can, in which the rotor is mounted, e.g. by plain bearings, represents a boundary between the medium to be pumped and an electric drive area and thus achieves a boundary between wet and dry areas. To improve the running properties of the rotor, for lubrication and cooling, and to avoid undesirable vibration and/or noise development, the can is sealed off from the fluid to be pumped with a radial shaft sealing ring. A water-oil emulsion can thus be used in the drive area, which improves the drive properties of the rotor and protects the bearing of the drive from particles in the fluid to be pumped. In most cases, simple, radially acting rubber seals are used as shaft seals, which have sealing lips or achieve an additional sealing effect via spring preload. The sealing properties are additionally increased by mostly circumferential coil springs in the rubber seal.

During operation, a lubricant and coolant film introduced once between the shaft and the seal between such seals and the shaft of the drive can be reduced or broken down by thermal influences or by axial shaft offset caused by pressure differences between the working medium and the working area or storage area in the can . As a result, the coefficient of friction between the rubber of the seal and the steel of the shaft can change or usually increase. The rubber seal is exposed to increased friction, in which case not only does sliding friction have to be present, but a static friction state can also set in temporarily for a very short time before a sliding friction state sets in again. A continuous alternation between sliding and static friction can occur, a so-called slip-stick effect. With the slip-stick effect, the rubber seal adheres to the shaft with a non-positive fit, rotates with the shaft over a few degrees or minutes of angle and deforms elastically until the rotational (tangential) component stresses cause sliding friction between the rubber and the shaft again steel adjusts. The seal then rotates or springs back into its original position. If this change of state between static and sliding friction is repeated in a constant sequence over time, an interference frequency can occur for this oscillating circuit, with the period of oscillation corresponding exactly to the time between sliding friction, static friction and renewed sliding friction. Frequencies of a few hundred hertz (Hz) up to a few kilohertz (kHz) are usually achieved. This slip-stick effect leads to an unpleasant development of noise and to additional undesirable material wear or accelerated component wear.

It is therefore the object of the invention to provide a pump, a pump system and a water-conducting household appliance which can avoid an unwanted noise development caused by the pump drive.

This object is achieved by a pump having the features of claim 1, a pump system having the features of claim 10 and a water-bearing household appliance having the features of claim 11.

According to one aspect of the present invention, a pump for a water-bearing household appliance is provided. The pump includes a shaft extending in an axial direction, a bearing bush configured to rotatably support the shaft about the axial direction, a driver configured to rotationally drive the shaft, and a seal configured to do so is to seal towards the shaft, wherein the seal is arranged in a sealing area of the shaft and the drive is arranged in an opposite drive area of the shaft with respect to the bearing bush, and wherein the bearing bush has at least one passage which is designed to connect the sealing area with the To bring drive area in communication.

Compared to the known state of the art, the bearing bush can be continuous from the drive area to the bearing area (for example realized by predominantly axial channels). In other words, a fluid can pass through the bearing bush (for example in the axial direction). The bearing bush can thus be designed in such a way that it is permeable for a fluid. Consequently, the seal, which seals the drive area and an area in which the shaft of the pump is journalled, against the fluid to be pumped, can also be lubricated during operation of the pump. More specifically, a fluid can pass from the drive area to the seal. In this way, the slip-stick effect and the associated development of vibration and noise can be reliably avoided. Furthermore, the service life of the seal can be increased since permanent lubrication of the seal can be ensured. Furthermore, the seal can be prevented from being additionally exposed to tangentially high-frequency stresses and strains.

The water-bearing household appliance can be a laundry treatment appliance or a washer-dryer. It is also conceivable that the water-bearing household appliance is a dishwasher. The pump can be a radial centrifugal pump and can have a synchronous pump drive.

The shaft may be a cylindrical member which extends rotationally symmetrically around its axis in the axial direction. The shaft can be made of a metal alloy, in particular steel. Preferably, the shaft has a circular cross-section. The circular cross section of the shaft has a radius extending in a radial direction. The axis of the shaft is preferably perpendicular to the circular cross-section of the shaft. In addition, the axis of the shaft can be perpendicular to the radial direction of the shaft. The shaft is preferably designed to be driven in rotation. To this end, the shaft can have a driven end, on which the shaft is driven, and a driving end, on which the shaft drives another element (e.g. an impeller (e.g. an impeller). The driven end can correspond to the driving end and the driven end, respectively opposite. The driven end may be in the drive area. The driving end may be located beyond the sealing area. The shaft may extend through the driving area and the sealing area. For example, the shaft may have a diameter of 3 mm to 3.5 mm, but also accept larger diameters.

A bearing bush can be an element for supporting the shaft, such as a plain bearing bush. A bearing bush can have the shape of a hollow cylinder. For example, the bushing may comprise steel, bronze, brass, a plastic, or a fiber reinforced plastic. The bearing bush can be designed to support a shaft in the pump so that it can rotate about the axis of the shaft. In particular, the bearing bush can be a plain bearing bush. In the plain bearing, the two parts that move relative to each other (e.g. the bearing bush and the shaft) can be in direct contact with each other. The bearing bush can be an integral or one-piece component. The Langer bushing can be designed to rotatably support the shaft in a housing (e.g. a can). The bearing bush can be fixed to the housing so that the shaft can rotate relative to the bearing bush. Furthermore, the pump or the pump drive can comprise a further bearing bush, which can be arranged in the drive area. Thus, the shaft can be mounted at two support points. For example, the bearing bush can be designed to fix, position or hold the seal.

A drive can be a device for generating a rotational movement and a rotationally acting torque. Furthermore, the drive can be designed to transmit the electromagnetic rotary movement (rotary field) to the shaft. The drive is preferably designed to drive the shaft in rotation. The drive can be an electric motor. The motor can be an asynchronous motor. Alternatively, the motor can be a permanently excited synchronous motor. A particularly simply constructed pump can thus be obtained. In the case of the synchronous motor, a constantly magnetized rotor can be entrained synchronously by a moving rotating magnetic field in a stator. A movement of the synchronous motor that is synchronous with the applied AC voltage preferably occurs. Thus, no direct mechanical contact (mechanical coupling) between rotor and stator is necessary. An advantageously sealed pump can thus be obtained. The rotor can be provided in the drive area, for example. The drive area can be sealed off from the stator. A drive area can be understood to mean a section of the shaft which has a drive. In other words, the drive area can extend in the axial direction along the shaft. Furthermore, a drive area can be understood to mean the section of the shaft which is arranged opposite the sealing area with regard to the bearing bush. The drive area can be directly adjacent to the sealing area.

The gasket may be an element configured to prevent or limit unwanted mass transfer from one side of the gasket to another side of the gasket. The seal may comprise EPDM (ethylene propylene diene rubber), NBR (acrylonitrile butadiene rubber), SBR (styrene butadiene rubber), an FKM (fluoro rubber) and/or a CR (chloroprene rubber). An unwanted mass transfer can be a liquid and/or a gas passing through the seal. In one embodiment of the present invention, the purpose of the seal is to prevent fluid to be pumped from penetrating into the working area or drive area or sealing area. Furthermore, the seal can be designed to be designed to prevent fluid from escaping from the work area and/or the sealing area to the fluid to be pumped. The pump can have a housing. The housing may have an opening through which the shaft extends. The seal can be arranged in this opening, so that the opening is essentially sealed off by the seal and the shaft. In other words, the seal can seal a gap between the shaft and an edge of the opening (ie, seal against the shaft). The seal can thus be designed to prevent fluid from transferring from an area outside the housing (for example from the pump pressure chamber) into the housing (for example into the gap housing of a glandless drive). The seal can be provided in such a way that it is arranged fixed to the housing of the drive (eg can). The shaft can rotate relative to the seal. A relative movement can thus take place between the shaft and the seal, which is accompanied by a friction torque due to the component contact, i.e. the friction between the components. Furthermore, the seal can be provided in such a way that it at least partially accommodates the bearing bush. In other words, the seal can extend along the axial direction and at least partially surround the bearing bush. The bearing bush can therefore be supported against the seal. A particularly reliable sealing of the housing (for example a can) can thus be effected, since the load that is radially carried away by the bearing bush acts on the seal and the sealing effect between the housing and the seal is thus improved. This means that tensioning elements in the seal can be dispensed with. As a result, the seal can be of particularly simple design. Furthermore, in the area in which the seal is in contact with the bearing bush, the seal can have a projection which projects radially inwards. The bearing bush can have a radial indentation which corresponds to the projection and which is in contact with the projection. Thus, an axial displacement of the bearing bush to the seal or to the drive housing (can) can be prevented or reduced with simple means.

The seal can define the sealing area. The sealing area can extend along the shaft (i.e. in the axial direction). The sealing area can be limited by the sealing point between the seal and the shaft and the bearing bush. A sealing area can also be understood as the section of the shaft which is opposite the drive area with regard to the bearing bush.

The fluid or medium can be a liquid, a gas or a mixture, which can reduce the friction between the shaft and the bearing bush and/or can bring about cooling of the shaft and/or the bearing bush and/or a rotor. The fluid can also be suitable for preventing or reducing corrosion of the shaft and/or the bearing bush. Furthermore, this can also include a component which is designed to prevent the fluid from freezing. The fluid may include a lubricant, a coolant, an anticorrosive, and/or an antifreeze. Furthermore, the fluid can be an aqueous solution or a water-oil emulsion, which then has damping properties, so that vibration noises of the rotor assembly are damped. Furthermore, the fluid can be present in two phases and be a mixture of liquid and air. The fluid can be stored in a container in the pump, the container being designed to deliver part of the fluid to the bearing bush during operation of the pump. Additionally or alternatively, the fluid can be provided in the drive area.

The passageway may be an opening, channel, or through hole in the bearing bush that also extends axially similar to the shaft bore in the bearing bush, but is not concentric with the shaft bore. A passageway may have a cylindrical shape. The passage can extend along a passage central axis and thus runs along a directional vector that has predominantly axial components. The passageway may have a circular, elliptical, or angular cross-section. The passageway may be configured to bring the sealing area into communication with the drive area. Communication can be understood in particular as fluidic communication. Accordingly, a fluid can be transported through the bearing bush in a predominantly axial direction. A transport of a fluid can be understood to mean any movement of the fluid, in particular a flow of the fluid. The fluidic communication, which is made possible by the at least one passage, has the advantage that the fluid can be distributed over the different areas of the shaft and can ensure lubrication, cooling, corrosion protection and/or frost protection for other components in other areas of the pump . In other words, the fluid can get from the drive area into the sealing area. As a result, a low coefficient of friction between the seal and the shaft over the entire service life of the water-bearing household appliance can also be ensured in the longer term. Furthermore, the slip-stick effect and the associated unpleasant vibration and noise development can be avoided.

According to one embodiment, the at least one passage is designed in such a way that a fluid can flow from the drive area through the bearing bush into the sealing area or from the sealing area into the drive area. The fluid preferably enters the passage of the bearing bush in the drive area and leaves the passage again on the opposite side of the bearing bush. The fluid can thus reach the seal and reduce friction there between the seal and the shaft. Furthermore, the fluid can lubricate and cool the contact area between the shaft and the seal. Furthermore, a fluid, which can include an anti-corrosion agent and/or anti-freeze agent, can be evenly distributed over the entire length of the shaft in the sealing area and in the working area, and thus protect the shaft against corrosion and/or frost over a large area or also heat generation due to friction on the seal .

According to a further embodiment, at least one passage extends through the bearing bush at a constant distance in the radial direction with respect to the shaft. The radial direction can be perpendicular to the axial direction. The distance between the passage central axis of the at least one passage and the axis of the shaft can be constant. In other words, the radial distance can be constant along the axis of the shaft. There may be multiple passages, each passage being the same, constant distance from its passage central axis to the axis of the shaft. The same spacing of the passage central axis to the axis of the shaft may also exist when the passage extends through the bearing bush in a curved manner relative to the shaft. In other words, the passage can extend at a constant radial distance from the bearing bore (i.e. the shaft) and in addition still have a tangential portion of the passage orientation vector and appear as a thread pitch (more details below). The at least one passage can preferably be arranged parallel to the shaft. This has the advantage that a fluid can get from the drive area to the sealing area as well as from the sealing area to the drive area over the shortest or shortest route. A bidirectional transport of fluid is thus made possible. Furthermore, this embodiment has the advantage that the bearing bush with the at least one passage can be manufactured easily and inexpensively.

According to a further embodiment, the at least one passage extends at a variable distance with respect to the shaft. The variable distance can be a variable radial distance. A variable distance can be understood as meaning that the passage central axis of the passage is skewed to the axis of the shaft. Skewed means that the center axis of the passage and the axis of the shaft neither intersect nor are parallel to each other. There may be multiple passes. Multiple passages may have the same variable distance from the axis of the shaft or different variable distances from the axis of the shaft. Due to the rotation of the shaft and possibly other components, radial pressure fields with different local pressures can build up. Furthermore, due to the axial misalignment of the passages, different pressures can prevail with different radial distances (ie radii) of the passage openings. Due to this pressure difference in the radial extent, a delivery flow of the fluid can be established, which can build up through the passage from the larger radius to the smaller radius.

The at least one passage with a variable distance from the axis of the shaft has the advantage that the direction of the fluidic communication can be influenced. The variable distance of the at least one passage can be selected in such a way that the fluid can flow exclusively or primarily from the drive area to the sealing area, or vice versa. Thus, for example, a certain pressure can be built up in the sealing area. As a result, on the one hand, the fluid can be reliably pressed between the seal and the shaft and, on the other hand, the sealing properties of the seal can be improved.

According to a further embodiment, at least one passage is open towards the shaft. The at least one passage can be open over the entire length of the passage towards the shaft in a radial direction. Thus, the fluid that passes through the passage can also come into direct contact with the shaft in the area of the bearing bush. Lubrication and/or cooling of the shaft between the bearing bush and the shaft can thus be implemented effectively or even more effectively.

According to a further embodiment, the at least one passage is partially open towards the shaft. The passageway may have one or more sections where the fluid comes in direct contact with the shaft. Furthermore, the passage can have one or more sections which are closed towards the shaft and in which the fluid does not come into direct contact with the shaft. Thus, the wave can be prevented from entering the passage or passages. In other words, the shaft can be prevented from doing so by the closed sections of the at least one passage, for example with increased bushing Wear to penetrate or snap into the passage and block it.

According to a further embodiment, the bearing bush has one to thirteen passages, preferably three to seven passages. When several passages are arranged, it has been shown that sufficient fluid can be conveyed into the sealing area in order to adequately wet or lubricate the seal. A number of three to seven passages has proven to be particularly advantageous since a uniform transport of fluid could be observed here. Furthermore, in this area there was sufficient pressure in the sealing area, so that the seal can be mechanically supported. The more passageways there are, the greater the amount of fluid that can pass through the bearing bush.

According to a further embodiment, the at least one passage has a diameter of at least 1.0 mm, preferably at least 1.5 mm. Thus, the fluid can be transported from the drive area to the sealing area to an extent sufficient to lubricate the seal. In the case of smaller diameters, an unfavorable flow resistance can arise in the passages, so that the fluid transport can be inhibited. In the diameter range of at least 1.5 mm, it was found that the bearing bush, despite the passages, was able to absorb the radial forces of the shaft very well without becoming deformed. In other words, very good mechanical strength of the bearing bush can be ensured here.

According to a further embodiment, the bearing bush has at least two passages whose diameters differ. With passages of different dimensions, it is possible to ensure that a sufficient volume flow of fluid can be achieved through the bearing bush, that is to say that particularly good mechanical stability of the bearing bush can also be achieved. This is particularly advantageous at high shaft speeds and thus increased loads on the bearing bush. It is advantageous that the bearing bush nevertheless has symmetry with respect to a plane running through the axis of the bearing bush. Sufficient strength of the bearing bush can be achieved in this way.

According to a further embodiment, at least one passage is arranged in such a way that the angle between the passage and the axis of the shaft is 1° to 45°, preferably 5° to 20°. Preferably, the angle between the passage and the axis of the shaft means the angle between the passage central axis of the passage and the axis of the shaft. This has the advantage that the direction of the fluidic communication can be influenced. The angle between the center line of the at least one passage and the axis of the shaft can be selected in such a way that the fluid can only get from the drive area to the sealing area by specifying the direction of rotation of the rotor in coordination with the axis inclination of the passages or the passage the other way round. Thus, not only hydraulic communication can be realized between the drive and the sealing area, but even a fluid flow that can be initiated by the rotor rotation. In addition, the amount of fluid that can pass through the passages of the bearing bush can be influenced via the angle of the axes to one another. A large angle reduces the amount of fluid that can get through the bearing bush or is even pumped, whereas a shallow angle can increase the amount of fluid that can get through the bearing bush. However, no dependency or increase in flow rate to the direction of rotation of the rotor can be derived. With a larger angle, the passage length can be increased, as a result of which the frictional resistances or flow resistances in the passage can also be increased. Furthermore, an inlet loss at an upstream end of the at least one passage can be reduced by arranging the at least one passage at an angle, since the opening cross section then increases at right angles to the bearing bush. In other words, the opening area of the at least one passage to the drive area and/or sealing area can be enlarged, as a result of which the fluid can enter the at least one passage particularly easily.

According to a further embodiment, at least two passages are provided, which are arranged such that they intersect or cross. Two intersecting ones can touch at least one point without the passage center axes of the passages touching. In the case of two passages which intersect, the passage center axes can touch at a point. A volume of fluid entering a first passage and another volume of fluid entering a second passage may contact in the area where the first and second passages intersect. As a result, improved mixing of the fluid can be achieved and separation of the components of the fluid, for example water and oil in the case of a water-oil emulsion, can be prevented.

According to a further embodiment, at least two passages are provided, which are arranged in such a way that they neither intersect nor cross. At least two passages that do not intersect can be understood as meaning who that the at least two passages do not touch. Two passages that do not intersect can be understood to mean that the passage center axes of the at least two passages are arranged skewed to one another. This has the advantage that possible flow resistances due to the mixing of fluid volumes in the area where different passages cross can be avoided. This also has the advantage that effective and fast fluidic communication can be achieved, which can then be designed for different operating points, for example, so that a different inclination of the passage axis is optimally specified for each different operating point.

Preferably, at least one passage extends substantially helically through the bearing bush. A substantially helical passage can be understood to mean that the shape of the at least one passage is substantially similar to a helix. In other words, the passage central axis of the at least one passage can extend in the form of a helix around the shaft through the bearing bush. The passage, which extends in a helical form (e.g., helical or thread form), may have a constant pitch around the shaft so that a constant deflection of the predominantly axial passage axis to the plain bearing axis in a tangential extension in the cylinder coordinate system is present. The advantage of a helical passage is that the pitch of the helix can be selected in such a way that the fluid is guided along the helix and thus undesired turbulence of the fluid when it hits the bearing bush or a passage can be prevented. In addition, the helical shape has the advantage that the direction of the fluidic communication can be fixed. Depending on the direction of rotation of the helix and depending on the choice of direction of rotation of a rotor or the shaft, the fluid can either only get from the drive area into the sealing area, but not from the sealing area into the driving area, or only from the sealing area into the driving area, but not from the drive area in the sealing area. The at least one helical passage and the shaft preferably have the same direction of rotation, so that the transport of the fluid is supported by the rotation of the shaft. The helical shape ensures efficient fluidic communication. The helix-like passage can be designed in a screw-like shape, so that virtually all threads have the same pitch. Alternatively, the helical passage can be implemented with a variable pitch. In this case, an embodiment would favor fluid transport in which the passage axis has greater gradients at the passage entrance and beginning of the channel, which then reduces as the axial extension continues, in order to also make the passage length through the plain bearing bush smaller than if the axis were designed with a constantly large inclination . Due to the prevailing shaft rotation, a dynamic pressure can be built up in the at least one helical passage, as a result of which the transport of fluid can be further promoted. In other words, by varying the radial distance between the axis of the passage and the axis of the bearing bush, the axis of the passage can be given a tangential characteristic, so that it is present in a helical shape.

An axial extent of the passages is preferably not lengthened by tangential portions, so that a flow resistance is not adversely affected. Consequently, an angle of the passage axis relative to the shaft axis can be between 5 and 20°. In this case, the longitudinal axis of the passage cannot be adjusted in a radial form, but can have an inclination which is represented tangentially in cylinder coordinates, so that a quasi-helical shape of the passage can be realized.

According to another aspect of the present invention, there is provided a pump system comprising a pump according to any one of the above aspects, and an impeller arranged on the sealing portion side of the shaft with respect to the bearing bush and provided to be rotatable together with the shaft is. The impeller (impeller) can be a rotary body surrounded by an annular or tubular or cylindrical housing, in particular for a pump for a water-bearing household appliance. The impeller is preferably designed and arranged on the shaft in such a way that the impeller is driven in rotation when the shaft is driven in rotation. Furthermore, the impeller is designed to increase a pressure in a medium to be pumped in a pump chamber. The impeller preferably has a plurality of straight or curved blades or ribs which can rotate in the fluid to be pumped.

According to a further aspect of the present invention, a water-bearing household appliance is provided, comprising at least one pump according to one of the above configurations. In particular, the water-carrying domestic appliance can be a washing machine or a washer-dryer.

According to another aspect of the present invention, there is provided a method of directing fluid through a bearing bush, the method comprising providing a Pump according to any of the above aspects, driving the shaft to rotate about an axial direction; Conveying fluid through the at least one passage in the bearing bush, so that the fluid gets from the working area into the sealing area. Preferably, the fluid in the sealing area lubricates the seal, especially in the contact area between the seal and the shaft. In this way, sliding friction between the seal and the shaft can be reduced and/or static friction effects between the shaft and the seal can be completely ruled out, which can lead to a slip-slide effect between the shaft and the seal. Preferably, the method further includes supplying fluid to the work area. The fluid can be supplied from a reservoir. Thus, sufficient fluid can be provided in the working area in the event that fluid has been discharged into the sealing area. This ensures adequate lubrication in both areas.

According to one embodiment of the invention, a pump is provided with a bearing bush, the bearing bush being designed as a radial plain bearing bush. The plain bearing bush can appear as a hollow cylinder. The fluid can be transported through the bearing bush via largely axial passages (e.g. grooves or channels with variable flow cross section, preferably round flow cross section) on the outer lateral surface of the plain bearing cylinder. Additionally or alternatively, the fluid can be transported through the bearing bush via largely axially running passages (e.g. grooves or channels with variable flow cross section, preferably round flow cross section) on the inner lateral surface of the plain bearing cylinder. The fluid can thus be transported through the bearing bush, so to speak, on the bearing friction surface. Additionally or alternatively, the fluid can be transported through a wall of the plain bearing bush through the bearing bush via largely axial passages (e.g. bores or channels with variable flow cross section, preferably round flow cross section). Thus, the passages can be performed as integrated channels in the bearing bush. A combination of the above measures is also conceivable in order to achieve even better fluid transport in the sealing area.

Furthermore, the invention is aimed at using a pump according to one of the above configurations in a water-bearing household appliance. The water-bearing household appliance is preferably a washing machine or a washer-dryer.

The advantages and effects that were mentioned in connection with the device also apply analogously to the method and vice versa. Individual features of different embodiments can be combined with other features or other embodiments and form new embodiments. The advantages and effects of the features mentioned also apply to the new embodiments.

• 1 zeigt eine schematische und perspektivische Darstellung einer Pumpe gemäß einer Ausführungsform der vorliegenden Erfindung.
• 2 ist eine schematische Darstellung eines Teils einer Pumpe gemäß einer Ausführungsform der vorliegenden Erfindung.
• 3 ist eine schematische Darstellung eines Teils einer Pumpe gemäß einer weiteren Ausführungsform der vorliegenden Erfindung.
• 4 ist eine schematische und perspektivische Ansicht einer Lagerbuchse einer Pumpe gemäß einer Ausführungsform der vorliegenden Erfindung.
• 5 ist eine schematische Darstellung einer Lagerbuchse einer Pumpe gemäß einer weiteren Ausführungsform der vorliegenden Erfindung.
• 6 ist eine schematische Darstellung einer Lagerbuchse einer Pumpe gemäß einer weiteren Ausführungsform der vorliegenden Erfindung.

In the following, embodiments of the present invention are described in detail with reference to the attached figures.

• 1 shows a schematic and perspective representation of a pump according to an embodiment of the present invention.
• 2 Figure 12 is a schematic representation of a portion of a pump according to an embodiment of the present invention.
• 3 Figure 12 is a schematic representation of a portion of a pump according to another embodiment of the present invention.
• 4 12 is a schematic and perspective view of a bearing bush of a pump according to an embodiment of the present invention.
• 5 12 is a schematic representation of a bearing bush of a pump according to another embodiment of the present invention.
• 6 12 is a schematic representation of a bearing bush of a pump according to another embodiment of the present invention.

1 12 is a schematic and perspective longitudinal sectional view of a pump drive 1 according to an embodiment of the present invention. The pump 1 includes a drive 4 which is provided in a drive area 7 . The drive 4 is designed to drive a shaft 2 in rotation about an axis (hereinafter referred to as the axial direction A). The shaft 2 is supported by a bearing bush 3 (also referred to as first bearing bush 3 ) and a second bearing bush 9 . The drive 4 is a permanently excited synchronous drive. More precisely, the drive 4 is a permanently excited synchronous drive based on the so-called wet-running principle. The shaft 2 is arranged in a can 12 . The can 12 is designed to be virtually fluid-tight, since it is sealed with a spring-loaded radial shaft sealing ring to the fluid-carrying pump pressure chamber. The can 12 can also be referred to as a housing. Inside the can 12, a water-oil emulsion is used to the Drive running properties of the drive 4 and the shaft 2 to improve. A fluid or medium (the so-called gap tube filling, lubricating and cooling medium) is thus arranged in the working area 7 . The working area 7 is delimited by the bearing bush 3 and the bearing bush 9 . Furthermore, the pump 1 includes a seal 5 which is designed to seal off the shaft 2 . In other words, the can 12 has an opening through which the shaft 2 extends. The opening 13 is sealed by the seal 5 in such a way that no fluid can enter the can from the outside from the pump pressure chamber to the inside, nor can a fluid pass through the seal 5 from the inside (can) to the outside (pump pressure chamber). The area of the shaft 2 in which the seal 5 is arranged is referred to as the sealing area 6 . In other words, the sealing area 6 is defined between the sealing point between the shaft 2 and the seal 5 and the bearing bush 3 . The seal 5 is in direct contact with the shaft 2 and thus primarily seals the can filling and thus prevents the loss of the can filling, although the drive is designed as a kind of “wet-running design principle”. The seal 5 is held or provided on the can 12 or pressed in axially. Therefore, the shaft 2 can move relative to the seal 5 during operation. In the further axial course of the shaft 2 away from the sealing area 6, an impeller (impeller) 11 is arranged, which is provided rotatably in a pump chamber or pump pressure chamber. By operating the shaft 2, the impeller (impeller) 11 is rotated, so that a pumping effect can be generated in the pump 1 according to the conveying principle of a radial centrifugal pump (ie a continuously operating flow machine). In the present embodiment, no seals are provided between the impeller (impeller) 11 and the seal 5, so that the seal 5 can come into contact with the fluid to be pumped (for example a mixture of laundry treatment agent and water). Between the seal 5 and the bearing bush 3 is thus normally neither the fluid from the work area 7, nor the fluid to be pumped from the pump pressure chamber. The present invention provides for at least one passage 8 (in 1 not shown), which is designed to bring the working area 7 into communication with the sealing area 6 in order to realize fluid transport. The fluid medium can thus reach the sealing area 6 from the working area 7 . As a result, the seal 5 can be lubricated from the inside, so that the contact area between the seal 5 and the shaft 2 can be lubricated by the sealing area 7 . As a result, a change between sliding and static friction can be avoided, since the effects of static friction can be completely ruled out. Furthermore, the sliding friction in the form of the coefficient of sliding friction is greatly reduced. Consequently, the slip-stick effect and thus the corresponding interference frequencies can be prevented. This allows the pump 1 to operate particularly quietly.

2 is a schematic longitudinal sectional representation of a detail of a pump 1. In 2 the sealing area 6 is shown enlarged. In contrast, only part of the working area 7 is shown. In the present embodiment, the bearing bushing 3 has on its outer circumference a recess which extends in the radial direction and into which a corresponding projection of the seal 5 engages. The bearing bushing 3 can thus be held by the seal 5 . More precisely, the bearing bush 3 can be secured against axial displacement. This enables a particularly simple design of the pump. Furthermore, at the in 2 shown sectional view a passage 8 recognizable. In 2 the left area is the area facing the pump pressure chamber.

3 Fig. 11 shows another embodiment of the present invention. In the present embodiment, the seal 5 has a double sealing lip on the side facing the pump pressure chamber. As a result, the can 12 can be sealed particularly reliably with respect to the pump pressure chamber. Otherwise, the present embodiment is similar to that in 2 illustrated embodiment.

4 12 is a side perspective and schematic representation of a bearing bush according to an embodiment of the present invention. The bearing bush has at least one passage 8 running along its outer circumference. In an installed or in an operating state, the fluid can therefore flow from the working area 7 to the sealing area 6 . The passage 8 is partly through the bearing bush 3 and partly through the can 12 (in 4 not shown) formed.

5 14 is a bearing bush 3 in rear view according to another embodiment of the present invention. In the 5 Bearing bush 3 shown has four passages 8 . The bearing bush 3 is in 5 shown in a view essentially along the axial direction A. Furthermore, it can be seen in the embodiment that the passages 8 are provided in the bearing bush 3 in such a way that they are arranged on the inner hollow cylindrical lateral surface of the bearing bush 3 . In other words, the passages 8 are open to the shaft 2. This can ensure that the fluid from the drive area 7 flows along the shaft 2 on the way to the sealing area 6 and also between the bearing bush 3 and the shaft 2 can unfold its effect. For example, the fluid can include a lubricant, a coolant, an anti-corrosion agent and/or an anti-freeze agent and bring these effects precisely to the point of contact between the shaft and plain bearing.

6 12 is another perspective and schematic rear view of a bushing 3 according to another embodiment of the present invention. The bushing 3 of the present invention also has 7 passages 8 . The passages 8 are only formed by the bearing bush 3 in the present embodiment. In other words, no other elements, such as the shaft 2 or the can 12, are needed to form the respective passage 8. In this way, fluid can be transported from the drive area 7 to the sealing area 6 without further components being integrated in the plain bearing bush.

In summary, the slip-stick effect can be prevented with the embodiments of the present invention, since through the passages 8, which mainly extend axially through the bearing bush 3, the seal 5 can also be lubricated and/or cooled from the drive side and so on the static friction effect between the shaft and the seal can be completely ruled out. In other words, a constant, low coefficient of friction for the sliding friction can be ensured between the friction partners (ie between the seal 5 and the shaft 2), so that the effects of static friction can be completely ruled out. In addition, a constant temperature and lubricating property between the friction partners can be ensured even during prolonged operation of the pump 1 .

Claims (11)

Pump (1) for a water-bearing household appliance (100), comprising: a shaft (2) extending in an axial direction (A), a bearing bush (3) which is designed to support the shaft (2) so that it can rotate about the axial direction (A), a drive (4) designed to drive the shaft (2) in rotation, and a seal (5) which is designed to seal against the shaft (2), the seal (5) being arranged in a sealing area (6) of the shaft (2) and the drive (4) in a bearing bush ( 3) opposite drive area (7) of the shaft (2) is arranged, and wherein the bearing bush (3) has at least one passage (8) which is designed to bring the sealing area (6) into communication with the drive area (7). Pump (1) according to claim 1 , wherein the at least one passage (8) is designed in such a way that a fluid can reach the sealing area (6) from the drive area (7) through the bearing bush (3). Pump (1) according to claim 1 or 2 , wherein the fluid comprises a lubricant, a coolant, a corrosion inhibitor and/or an antifreeze. A pump (1) according to any one of the preceding claims, wherein at least one passage (8) extends through the bearing bush (3) at a constant distance in the radial direction (R) with respect to the shaft (2). A pump (1) according to any one of the preceding claims, wherein at least one passage (8) extends through the bearing bush (3) at a variable distance in the radial direction (R) with respect to the shaft (2). Pump (1) according to one of the preceding claims, wherein at least one passage (8) towards the shaft (2) is open at least in sections. Pump (1) according to any one of the preceding claims, wherein at least one passage (8) is arranged to have an angle between the passage (8) and the axial direction (A) of the shaft (2) of 1° to 45°, preferably 5° to 20°. A pump (1) according to any one of the preceding claims, wherein at least two passages (8) are provided and arranged to intersect or cross. Pump (1) according to any one of the preceding claims, wherein at least one passage (8) extends substantially helically through the bearing bush (3). A pump system (10) comprising a pump (1) according to any one of the preceding claims, and an impeller (11) arranged and provided on the shaft (2) on the sealing portion (6) side with respect to the bearing bush (3). that it is rotatable together with the shaft (2). Water-bearing household appliance (100), comprising at least one pump (1) according to one of Claims 1 until 9 .

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