EP3276127B1 - Geared fluid machine - Google Patents

Description

The invention relates to a gear fluid machine, with a machine housing, a first gear and a second gear meshing with the first gear, wherein the first gear and the second gear are each rotatably mounted with respect to an axis of rotation in the machine housing and each at least partially on the end face with at least one axial play in the machine housing, which has a pressure field on its side facing away from the gearwheels, which is encompassed by a circumferential seal, which on the one hand lies against a first support surface of the axial disk and on the other hand on a second support surface of the machine housing.

The gear fluid machine can be designed, for example, as a gear pump or as a gear motor. An embodiment as an internal gear fluid machine or as an external gear fluid machine is also possible, so that the gear fluid machine can be present as an internal gear pump, internal gear motor, external gear pump or external gear motor. In either case, the gear fluid machine has the first gear and the second gear. The two gear wheels mesh with one another, the first gear wheel having a first tooth system and the second gear wheel having a second tooth system and the two tooth systems meshing with one another at least in some areas. In the following, the internal gear fluid machine will be discussed purely by way of example. Of course, the statements can always be easily transferred to the external gear fluid machine.

In the case of the internal gear fluid machine, the first gear is designed as a pinion and the first toothing is designed as an external toothing, whereas the second gear is a ring gear, which has the second toothing designed as an internal toothing. The pinion is arranged in the ring gear in such a way that the two toothings mesh with one another. The pinion is mounted eccentrically with respect to the ring gear. This means that the first gear wheel is mounted so as to be rotatable about a first axis of rotation and the second gear wheel is mounted so that it can rotate about a second axis of rotation, the two axes of rotation preferably being arranged parallel to one another at a distance. If the gear fluid machine is designed as an external gear fluid machine, then the two gears are located as meshing external gears. In this case, too, the two axes of rotation are arranged at a distance from one another in parallel.

In the case of an embodiment of the gear fluid machine as a pump, the gear wheels are acted upon by a rotary movement, whereby a conveying effect is exerted on a fluid present in the gear fluid machine. If, on the other hand, the gear fluid machine is designed as a motor, its fluid is supplied, as a result of which the gear wheels are set in rotation. To this extent, a torque is provided on one of the gears, which can be tapped. The following only describes the pump in more detail. However, the explanations can always be transferred to the engine.

The gear fluid machine has the first gear, the second gear and the machine housing as essential components. The two gears are rotatably mounted in the machine housing, namely about the first axis of rotation and the second axis of rotation. To achieve the eccentric mounting of the two gears, the two axes of rotation are spaced apart, in particular spaced apart in parallel, to one another. In the case of the internal gear fluid machine, the pinion is arranged in the ring gear and accordingly has an outer diameter which is smaller than an inner diameter of the ring gear. Both the pinion and the ring gear are essentially round in cross section with respect to the respective axis of rotation. The outer diameter of the pinion and the inner diameter of the ring gear are selected such that the outer toothing of the pinion, viewed in the circumferential direction with respect to the second axis of rotation, only engages with a region of the inner toothing of the ring gear.

The first gear is arranged, for example, on a drive shaft of the gear fluid machine, in particular connected to it in a rotationally fixed manner. In this respect, the first gearwheel can be driven via the drive shaft and set in a rotary movement about the first axis of rotation. Because of the second toothing meshing with the first toothing, the rotational movement of the first gear is also impressed on the second gear. In the case of the internal gear pump, the first gear is driven directly by the drive shaft, while the second gear is only driven indirectly by the drive shaft via the first gear. Both the first tooth system and the second tooth system each have a large number of teeth and interdental spaces between the teeth. In the case of the internal gear pump or the external gear pump, the conveying effect is achieved by the meshing of the first toothing and the second toothing.

When looking at any tooth of the first gear during a complete revolution of the first gear, this tooth temporarily engages in a tooth gap of the second toothing. Before the tooth engages in the interdental space, the fluid is present in the latter. By engaging, the fluid is preferably conveyed to a pressure side or into a pressure chamber of the gear fluid machine, namely starting from a suction side or from a suction chamber. The pressure chamber is formed, for example, in the machine housing of the gear fluid machine. If the gear fluid machine is designed as a gear fluid motor, the fluid flows out of the pressure chamber in the direction of the suction side or the suction chamber of the gear fluid machine, whereby the first gear and the second gear are driven. In this respect, the gear fluid motor represents the kinematic reversal of the gear fluid pump.

In the machine housing, the at least one axial disk is arranged, which rests at least in regions on an end face of the first gear and / or on an end face of the second gear. The axial disk creates a seal, in particular the pressure side with respect to the suction side, so that the fluid present in the gear fluid machine cannot flow past the end face of the first gear or the second gear. Of course, an axial disk is preferably arranged on both sides of the first gearwheel and the second gearwheel. However, only one of these axial disks is always discussed below; however, the explanations are always transferable. For example, the axial disks are designed symmetrically to one another or are even present as identical parts.

In order to always achieve a reliable seal by means of the axial disk, it is arranged in the machine housing with axial play with respect to the axis of rotation or the axes of rotation. In order to urge the axial disk during operation of the gear fluid machine in the axial direction in the direction of the first gear and / or the second gear, in particular the first gear and / or the second gear, the axial disk has the gears on its axial direction facing away from a print field. The pressure field is preferably in the form of a depression in the axial disk, which is preferably closed at the edge, that is to say has a circumferential edge. The recess extends through the axial disk in the direction of the gears only partially, that is not completely. In this respect, it has a continuous floor.

The pressure field or the depression is pressurized with fluid under pressure at least during operation of the gear fluid machine. The fluid is preferred the same that is present in the pressure chamber and / or the suction chamber of the gear fluid machine. For example, the pressure field is fluidically connected to the pressure side of the gear fluid machine, in particular via at least one flow channel formed at least partially or completely in the machine housing. A throttle and / or a diaphragm can optionally be provided in the flow channel in order to set the desired pressure in the pressure field.

The pressure field is encompassed by the circumferential seal, which is arranged on the axial disk. For example, the seal is arranged in a stationary manner in a recess in the axial disk and / or in a recess in the machine housing. The seal completely surrounds the pressure field and is designed as a circumferential seal. The seal rests - viewed in the axial direction - on the one hand on a support surface of the axial disk and on the other hand on a second support surface of the machine housing, the support surfaces preferably being arranged parallel to one another. Due to the sealing of the pressure field by means of the seal, the axial disk is pushed by the pressurized fluid present in the pressure field in the direction of the first gear and / or the second gear, so that the axial disk is preferably on the face of the first gear - or the second gear is applied.

From the pamphlet DE 10 2012 213 771 A1 For example, an internal gear pump with an axial disk is known, which rests against the end faces of a ring gear and a pinion of the internal gear pump for the lateral delimitation of a pump chamber and which has a pressure field on an outer side facing away from the ring gear and the pinion, which is sealed with a sealing ring that defines the pressure field encloses. It is provided that the internal gear pump has a sealing arrangement with the sealing ring, which has the shape of an outline of the pressure field and an L-shaped ring cross-section, and with an elastic ring that rests on the inside in the L-shaped ring cross-section of the sealing ring. The pamphlet DE7500496U shows a gear fluid machine according to the preamble of claim 1.

It is the object of the invention to propose a gear fluid machine which has advantages over known gear fluid machines, in particular enables better sealing of the pressure field while at the same time simplifying assembly.

According to the invention, this is achieved with a gear fluid machine having the features of claim 1. It is provided that the seal is U-shaped in section, in particular at least in some areas, and has a first sealing leg resting on the first support surface, a second sealing leg resting on the second support surface, and one the first sealing leg and the second sealing leg connecting connecting leg.

In the context of this description, the seal is partially viewed in section. The section is preferably to be understood as a seal cross-section which corresponds to a part of a longitudinal section through the seal, the sectional plane of this longitudinal section accommodating the axis of rotation of the first gear and / or the second gear or being at least arranged parallel to it. The seal cross-section now designates that part of the longitudinal section which is present on one side of an imaginary plane perpendicular to the cutting plane. Because the seal is designed circumferentially, two of these areas of the seal are opposite one another in the longitudinal section. If the section of the seal is referred to, only one of these areas is preferably meant. If the seal is viewed as a circumferential sealing ring with a continuous, in particular curved and / or ring-shaped, longitudinal center axis, the seal cross section is a cross section through the seal with respect to this longitudinal center axis.

Seen in section, the seal is U-shaped and has three legs, namely the first sealing leg, the second sealing leg and the connecting leg. The two sealing legs are arranged at a distance from one another when viewed in section and are connected to one another by the connecting leg. The two sealing legs and the connecting leg are preferably designed in one piece and / or made of the same material. The latter is to be understood as meaning that the sealing leg and the connecting leg are made of the same material. The seal preferably has only the two sealing legs and the connecting leg, so that overall the seal as such consists of just one material, which can also be referred to as the sealing material. The seal has the shape described at least in some areas, that is to say not necessarily along its entire extent. However, the shape is preferably present along the entire extent of the seal.

As seen in the longitudinal section through the gear fluid machine, the first sealing leg now rests on the first support surface and the second sealing leg on the second support surface. More precisely, the first sealing leg rests with a first sealing surface on the first support surface and the second sealing leg with a second sealing surface rests on the second support surface. The two sealing surfaces are preferably each arranged on the outside of the seal, that is to say on opposite sides in a longitudinal section through the gear fluid machine Sides of the seal or arranged on opposite sides of the two sealing legs.

Such a configuration of the seal enables a simple setting of a spring rate of the seal, which influences the contact pressure of the seal on the axial disk and on the machine housing. Depending on the manufacturing tolerances of the gear fluid machine, for example the machine housing, the gear wheels and / or the axial disk, the spring effect of the seal can result in different contact pressure forces after assembly of the gear fluid machine, corresponding to different axial pretensions of the seal.

In the case of known seals, in extreme cases there may be a non-existent or a very high contact pressure, which can result in various disadvantages, such as insufficient sealing effect and the associated loss of efficiency of the gear fluid machine, poor volumetric efficiency and / or a high frictional torque generated by the axial disk is exerted on the first gear and / or the second gear. The latter causes a deterioration in the hydraulic-mechanical efficiency of the gear fluid machine and possibly even increased wear on a running surface of the axial disk on which the first gear and / or the second gear rest with their respective end faces.

The described configuration of the seal, on the other hand, enables a gear fluid machine in which the problems mentioned do not occur because the axial preload of the seal and consequently the pressure force of the axial disk on the first gear and / or the second gear have an advantageous course over a spring travel of the seal. This is brought about by an advantageous spring characteristic of the seal, that is to say the course of the spring force caused by the seal over the spring travel.

Another embodiment of the invention provides that the seal consists of an elastic material, in particular polyurethane, and / or is designed without a support ring. It has already been pointed out above that the two sealing legs and the connecting leg are preferably made of the same material and, in this respect, are made of the same material. Polyurethane, for example, is used as a material. Additionally or alternatively, the seal is designed without a support ring, so in particular has none Lock washer made of metal or another elastic material. Rather, the seal consists exclusively of the sealing material.

Alternatively, the seal can of course be assigned a support ring or the seal can have such a support ring. The support ring is arranged, for example, between the first sealing leg and the first support surface and rests against both. Alternatively, it is arranged between the connecting leg and the machine housing and also rests against both. The support ring is preferably made of a different material than the seal, in particular made of metal. For example, the seal is attached to the support ring, in particular with a material fit. For example, the seal is molded onto the support ring.

Within the scope of a further embodiment of the invention, it is provided that the seal, viewed in section, is symmetrical with respect to a plane of symmetry running at a distance from the sealing legs, in particular centrally, through the connecting leg. The plane of symmetry or a line of symmetry lying in the plane of symmetry and the plane of section is preferably perpendicular to the connecting leg. It is arranged at a distance from the two sealing legs, for example it is located in the middle between the sealing legs. The seal is now configured identically on both sides of the plane of symmetry or the straight line of symmetry, in particular it is symmetrical with respect to the plane of symmetry.

In the case of the central arrangement of the plane of symmetry with respect to the sealing legs, this means that the sealing legs each have the same distance from the plane of symmetry and are also designed to be identical to one another, in particular have the same dimensions. Such a symmetrical configuration of the seal enables extremely simple assembly of the gear fluid machine, which can also be done mechanically, in particular fully automatically. This is achieved in particular through the one-piece design of the seal, the required sealing effect of the pressure field being able to be achieved by means of the one-piece seal alone. It is therefore not necessary, as is known from the prior art, to be fitted separately from one another.

A further development of the invention provides that the sealing legs, viewed in section, in the relaxed state of the seal, have free ends inclined away from one another in the direction facing away from the connecting leg. The relaxed state of the seal is an unassembled state of the seal, that is to say, for example, one immediately before installation to understand the seal present pre-assembly state of the seal. The seal exhibits this state, for example, after its manufacture until its assembly. During assembly, the seal can be deformed, by means of which the desired pretensioning of the seal and, accordingly, the desired contact pressure of the axial disk on the first gear and / or the second gear is achieved. This contact pressure is at least present as long as the pressure field is not acted upon by pressurized fluid and is thus depressurized.

Each of the sealing legs has a free end on its side facing away from the connecting leg. The free ends or the sealing legs are now inclined away from one another in the direction facing away from the connecting leg, so that - again viewed in section - imaginary extensions of the sealing legs intersect at a certain angle. Additionally or alternatively, in their relaxed state, the sealing legs can also be angled with respect to the axis of rotation of the first gear wheel or the second gear wheel, that is to say enclose an angle with it that is greater than 0 ° and less than 90 °. Because of this configuration of the seal, it is compressed in the axial direction with respect to the axis of rotation during assembly of the gear fluid machine, that is to say the free ends of the seal legs are displaced towards one another. This sets the preload of the seal.

The invention also provides that the connecting leg, seen in section, at least on its side facing away from the sealing legs, has an extension in the axial direction with respect to one of the axes of rotation that is smaller than the distance between the first support surface and the second support surface when the axial disk is in contact with the machine housing . In other words, the width of the connecting leg is smaller than the distance between the support surfaces when the axial disk rests against the machine housing, that is to say it is maximally displaced onto it. Such a configuration of the seal prevents the spring characteristic of the seal from being influenced too much by the connecting leg. If the width of the connecting leg were greater than the distance between the two support surfaces when the axial disk rests against the machine housing, a very steep rise in the spring characteristic would result if the axial disk were shifted towards the machine housing during operation of the gear fluid machine. This can be prevented by the configuration described.

A further embodiment of the invention can provide that sides of the free ends facing away from one another have a greater distance from one another than the first support surface and the second support surface in the relaxed state of the seal, in particular when the axial disk is in contact with the machine housing. In the relaxed state of the seal, the two sealing legs should protrude beyond the connecting leg as seen in section. Seen in the longitudinal section with respect to the axis of rotation, the distance between the outer and therefore remote sides of the free ends, which corresponds to the maximum dimensions of the seal in the axial direction in this state, should be greater than the distance between the two support surfaces, in particular when the axial disk is attached to the Machine housing. Correspondingly, said distance is greater than the width of the connecting leg.

The distance between the sides of the free ends facing away from one another is preferably intended to mean their greatest distance, this being determined in a plane perpendicular to the plane of symmetry. The distance corresponds, for example, to the distance between the support surfaces when the axial disk is in contact with the machine housing plus an axial play and / or a preload projection. The axial play is greater than zero. For example, based on the distance between the support surfaces, it is at least 5%, at least 10%, at least 15%, at least 20% or at least 25%. The preload projection is preferably selected such that the axial disk is subjected to a certain preload.

Furthermore, it can be provided within the scope of a preferred embodiment of the invention that each of the sealing legs, viewed in section, is delimited by a first imaginary straight line on its side facing the other of the sealing legs and by a second imaginary straight line on its side facing away from the other of the sealing legs , wherein the first straight line and the second straight line are angled to one another in the relaxed state of the seal. The first straight line defines the sealing surface of the respective sealing leg lying against the support surface, while the second straight line defines an inner surface of the respective sealing leg facing away from the sealing surface. The two straight lines each have an extension that differs from zero, so that the sealing surface and the inner surface are at least partially planar or even. The angle enclosed by the two straight lines is preferably identical for the two sealing legs. However, different angles can also be implemented. The included angle is, for example, at least 2.5 °, at least 5 °, at least 7.5 °, at least 10 °, at least 15 ° or at least 20 °.

A preferred embodiment of the invention provides that the connecting leg is rectangular when viewed in section and has at least one bevel or a round edge on its side facing away from the sealing legs. The seal is preferably arranged in a recess which is present in the machine housing or the axial disk. The recess preferably has a bevel or round edge adapted to the bevel or round edge, the adaptation preferably being provided with regard to the shape and / or the dimensions. Particularly preferably, the bevel or edge of the connecting leg rests continuously on the bevel or edge of the recess after the seal has been installed.

For a further embodiment of the invention it can be provided that, viewed in section, the connecting leg has an extension in the radial direction that is greater than the extension of the first sealing leg and / or the extension of the second sealing leg in the axial direction. The two sealing legs preferably each extend inward in the radial direction, starting from the connecting leg. The section described here can therefore be understood as a longitudinal section with respect to the axis of rotation. In other words, it is now provided that a material thickness of the connecting leg is greater than a material thickness of the sealing legs, the same material thickness preferably being used for the two sealing legs. The material thickness is in the radial direction for the connecting leg and in the axial direction for the sealing leg.

Furthermore, it can be provided within the scope of a further embodiment of the invention that the free ends of the sealing legs, seen in section, have at least one rounding that is present between the first imaginary straight line and the second imaginary straight line, in particular extending from the first imaginary straight line to the second imaginary straight line extends. When viewed in section, the free ends are, for example, flat, that is to say they are bounded by a straight line. This straight line can now be connected to the first straight line or the second straight line via the at least one rounding, so that the rounding extends from the straight line to the first straight line or the second straight line.

Preferably, there is such a rounding on both sides of the straight line, so that a first of the roundings extends from the straight line to the first imaginary straight line and a second of the roundings extends from the straight line to the second imaginary straight line. Alternatively, it can of course be provided that the two imaginary straight lines are only a rounding are connected to one another so that the rounding extends from the first imaginary straight line to the second imaginary straight line.

The embodiment described is provided for at least one of the sealing legs, but preferably for both sealing legs. The radius of the rounding can in principle be chosen as desired. For example, the rounding represents a segment of a circular arc, that is to say has a continuously constant curvature. The rounding preferably runs at least on one side, but particularly preferably on both sides, tangentially into the first straight line or the second straight line.

A further embodiment of the invention provides that the seal has at least one first sealing area and at least one second sealing area, the first sealing area and the second sealing area having different sealing cross-sections. As already explained above, the seal is designed circumferentially. If only exactly one first sealing area and exactly one second sealing area are provided, then these merge into one another on both sides. In other words, the first sealing area merges into the second sealing area on the one hand as well as on the other, a first end of the first sealing area merging into a first end of the second sealing area and a second end of the first sealing area merging into a second end of the second sealing area.

Of course, several first sealing areas and several second sealing areas can also be present. For example, the seal then consists alternately of one of the first sealing areas and one of the second sealing areas, so that first sealing areas and second sealing areas alternate. For example, it is provided here that, based on the course of the seal, the first sealing area or the first sealing areas each and / or overall have a smaller extent than the second sealing area or the second sealing areas. Particularly preferably, each of the first sealing areas has a smaller extension than each of the second sealing areas. The two sealing areas, that is to say the first sealing area and the second sealing area, can have different properties. They preferably differ only with regard to their cross section, that is to say they are configured differently when viewed in cross section. Additionally or alternatively, however, they can also differ with regard to the material, in particular consist of different materials.

It is preferably provided that the seal has the configuration described above both in the first sealing area and in the second sealing area, i.e. is U-shaped when viewed in section and has the first sealing leg, the second sealing leg and the connecting leg connecting them. Alternatively, however, it can also be provided that the seal deviates from this shape in one of the sealing areas. For example, the seal in one of the sealing areas is designed as a block when viewed in section, so that the connecting leg is only present in an imaginary shape and together with the sealing legs form a solid block. In this case, the otherwise free ends of the sealing legs are directly connected to one another. For example, the seal here is trapezoidal, that is to say, when viewed in section, it is delimited by two opposing parallel lines and two spaced-apart lines connecting these lines and angled against each other.

A particularly advantageous embodiment of the invention provides that the distance between the opposite sides of the free ends of the sealing legs in the relaxed state of the seal has a first value in the first sealing area and a second value different from the first value in the second sealing area. The cross sections of the seal therefore differ between the two sealing areas with regard to the distance that is present in the relaxed state of the seal. In the first sealing area the distance should have the first value and in the second sealing area the second value. The second value is different from the first value. It is particularly preferably smaller.

A further advantageous embodiment of the invention provides that the height of the connecting leg in the first sealing area has a first value and in the second sealing area a second value different from the first value. The height of the connecting leg corresponds to the material thickness of the connecting leg. The height or the material thickness of the connecting leg of the seal should now be different for the two sealing areas. To this end, the height of the connecting leg corresponds to the first value in the first sealing area and to the second value in the second sealing area. The second value is different from the first value. The second value is particularly preferably smaller than the first value.

An embodiment is particularly preferred, according to which the first sealing area and the second sealing area are mutually opposite both in terms of the distance between them Differentiate sides of the free ends of the sealing legs in the relaxed state of the seal and in the height of the connecting leg. For example, the first value for the distance is smaller than the second value, whereas the first value is greater than the second value for the height. The values for the distance and the height are particularly preferably selected in such a way that the same spring rates of the seal or its sealing legs are achieved that act between the machine housing and the axial disk.

A further development of the invention provides that the first sealing area and the second sealing area merge smoothly into one another via a transition area. The transition area is to this extent between the first sealing area and the second sealing area. For example, such a transition area is provided for each transition between a first sealing area and a second sealing area or vice versa, so that such a transition area is present between each first sealing area and the second sealing area or areas directly adjacent to it.

In the transition area, the cross sections of the first sealing area and the second sealing area gradually converge to one another. Over the extension of the transition area, the distance between the sides of the free ends facing away from one another and / or the height of the connecting leg change starting from the first sealing area up to the second sealing area. Alternatively, it can of course be provided that the first sealing area and the second sealing area directly adjoin one another, that is to say merge directly into one another or run into one another.

Finally, within the scope of a further embodiment of the invention, it can be provided that the first sealing area and the second sealing area are connected to one another via a bend, the bend having a greater curvature than the first sealing area and the second sealing area. Along the seal, this has a curvature value, which can also be zero, so that the seal runs straight. The more the curvature value deviates from zero, the more pronounced the curvature.

The first sealing area and the second sealing area are now connected to one another via the bend. The bend can, for example, coincide with the transition area or the transition area can represent the bend. The bend is characterized by a greater curvature in comparison with the first sealing area and the second sealing area, so that the curvature value for the bend is greater in absolute terms is as for the first sealing area and the second sealing area, in each case considered over their entire extent. For example, the first sealing area and the second sealing area are at an angle to each other at their ends adjoining the bend, which is preferably at most 135 °, at most 90 ° or at most 45 °, but in any case greater than 0 °. For example, the angle is at least 45 ° and at most 135 °, at least 60 ° and at most 120 °, at least 75 ° and at most 105 ° or approximately or precisely 90 °.

For example, the seal in the first sealing area runs almost straight, that is, it has a comparatively small curvature, in particular in comparison with the second sealing area, which is preferably more curved than the first sealing area. In other words, the greatest curvature of the first sealing area is smaller than the greatest curvature of the second sealing area, which in turn is smaller than the greatest curvature of the bend.

Figur 1

eine schematische Längsschnittdarstellung durch einen Bereich einer Zahnradfluidmaschine,

Figur 2

einen vergrößerten Ausschnitt der Längsschnittdarstellung,

Figur 3

einen Schnitt durch eine Dichtung in einer ersten Ausführungsform,

Figur 4

einen Schnitt durch eine zweite Ausführungsform der Dichtung,

Figur 5

eine schematische Darstellung der Dichtung in Draufsicht,

Figur 6

einen Schnitt durch die Dichtung in einem ersten Dichtungsbereich der Dichtung,

Figur 7

einen Schnitt durch die Dichtung in einem zweiten Dichtungsbereich der Dichtung, sowie

Figur 8

einen Schnitt durch die Dichtung in einer alternativen Ausgestaltung des ersten Dichtungsbereichs.

The invention is explained in more detail below with reference to the exemplary embodiments shown in the drawing, without restricting the invention. It shows:

Figure 1

a schematic longitudinal section through a region of a gear fluid machine,

Figure 2

an enlarged section of the longitudinal section,

Figure 3

a section through a seal in a first embodiment,

Figure 4

a section through a second embodiment of the seal,

Figure 5

a schematic representation of the seal in plan view,

Figure 6

a section through the seal in a first sealing area of the seal,

Figure 7

a section through the seal in a second sealing area of the seal, and

Figure 8

a section through the seal in an alternative embodiment of the first sealing area.

The Figure 1 shows a schematic longitudinal section through a gear fluid machine 1, which is designed here, for example, as an internal gear fluid pump. The gear fluid machine 1 has a first gear 2 configured as a pinion, a second gear 3 configured as a ring gear and a machine housing 4. The first gear 2 has an external toothing, not shown, which meshes with an internal toothing of the second gear 3, also not shown in detail. The first gear 2 is rotatably mounted with respect to an axis of rotation 5, while a rotatable mounting of the second gear 3 is provided about a further axis of rotation, not shown here, which is arranged at a parallel distance from the axis of rotation 5. The gears 2 and 3 are so far mounted eccentrically to each other. The external teeth of the first gear 2 are spaced apart from the internal teeth of the second gear 3 at least in some areas. A filler piece 6, which is preferably sickle-shaped, can be arranged in this area. The filler piece 6 can be formed in one piece or in several parts.

The machine housing 4 can - as shown here - be designed in several parts. In the axial direction between the gears 2 and 3 on the one hand and the machine housing 4 on the other hand, the gears 2 and 3 axial disks 7 and 8 are arranged on the end face. The axial disks 7 and 8 are located on opposite sides of the gears 2 and 3 in the axial direction. They are arranged in the machine housing 4 with little play in the axial direction. They are preferably mounted in a rotationally fixed manner with respect to the machine housing 4. Only the axial disk 7 is discussed in more detail below. However, the explanations can be used analogously for the axial disk 8.

The axial disk 7 has a pressure field 9 on its side facing the machine housing 4 and, in this respect, facing away from the gears 2 and 3, which is designed, for example, in the form of a depression in the axial disk 7. The pressure field 9 can be acted upon with pressurized fluid via a fluid channel 10 which is formed in the machine housing 4. For example, the pressure field 9 is flow-connected via the fluid channel 10 to a pressure side of the gear fluid machine 1 not shown here. During operation of the gear fluid machine 1, the pressure field 9 is pressurized via the fluid channel 10 and is accordingly pushed in the axial direction in the direction of the gear wheels 2 and 3.

In order to ensure a reliable pressure build-up in the pressure field 9, a seal 11 is assigned to the pressure field 9. The seal 11 preferably completely surrounds the pressure field 9 and is thus ring-shaped, although not necessarily circular. Much more the seal 11 can be non-circular, that is, deviate from a circular shape. For example, the pressure field 9 or the corresponding depression is approximately kidney-shaped, so that the seal 11 is also arranged in a kidney shape. The seal 11 rests, on the one hand, on a first support surface 12 of the axial disk 7 and, on the other hand, on a second support surface 13 of the machine housing 4 in a sealing manner. The seal 11 consists of an elastic material so that, after the gear fluid machine 11 has been assembled, a preload can be applied to the axial disk 7 with the aid of the seal 11, which in turn causes a specific contact pressure of the axial disk 7 in the axial direction on the gear wheels 2 and 3.

The Figure 2 shows a detail from the above-described longitudinal sectional view of the gear fluid machine 1. In particular, the machine housing 4 and the axial disk 7 can be seen partially and the seal 11 completely. It becomes clear that the seal 11 is arranged in a recess 14 of the machine housing 4. In this case, the seal 11 rests in a sealing manner with a first sealing surface 15 on the first support surface 12 and with a second sealing surface 16 on the second support surface 13. The first sealing surface 15 is present on a first sealing leg 17, while the second sealing surface 16 is formed on a second sealing leg 18. The two sealing legs 17 and 18 are arranged at a distance from one another in the axial direction with respect to the axis of rotation 5 and are connected to one another via a connecting leg 19, so that overall the seal 11 is U-shaped in section.

As indicated by the hatching, the seal 11 is formed in one piece and made of a single material from a sealing material. Polyurethane, for example, can be used as the sealing material. In particular, the seal 11 is designed without a support ring, that is to say does not have a support ring, for example a metallic one. In this respect, the seal 11 consists exclusively of the sealing material. Alternatively, of course, such a support ring can be provided. The connecting leg 19 is essentially rectangular in section and has rounded edges 20 on its sides facing away from the sealing legs 17 and 18. One of the round edges 20 rests against a corresponding round edge 21 of the recess 14.

It can be seen that the recess 14 has larger dimensions in the radial direction with respect to the axis of rotation 5 than the seal 11. Due to the design of the seal 11 as a circumferential seal, it has an inherent spring force which is directed towards an enlargement in the radial direction, so that the seal 11 or its connecting leg 19 is always pushed against a step 22 delimiting the recess 14 outward in the radial direction. On the side opposite the step 22 in the radial direction, the recess 14 is delimited by a web 23 which separates the recess 14 from the fluid channel 10. However, the web 23 is optional and can accordingly be omitted.

It can be clearly seen that the seal 11, seen in section, is designed symmetrically with respect to a plane of symmetry 24, the plane of symmetry 24 preferably being perpendicular to the axis of rotation 5 and being arranged centrally between the sealing legs 17 and 18. In other words, the plane of symmetry 24 is perpendicular to a longitudinal center axis 25 of the connecting leg 19.

The Figure 3 shows a section of the seal 11 in a first embodiment, the seal 11 being in a non-installed state, that is to say in particular in a pre-assembly state. Accordingly, the seal 11 is relaxed, so that, due to their spring action, the sealing legs 17 and 18 extend from one another in the axial direction on their side facing away from the connecting leg 19, so that their distance in this direction increases with increasing distance from the connecting legs 19. In addition, the plane of symmetry 24 and the longitudinal center axis 25 are again indicated. A respective longitudinal center axis 26 and 27 is also indicated for the sealing legs 17 and 18. Furthermore, an imaginary logical separation between the sealing legs 17 and 18 on the one hand and the connecting leg 19 on the other hand is shown. It can thus be seen that the connecting leg 19 represents a type of base body of the seal 11, from which the sealing legs 17 and 18 extend and, viewed in longitudinal section with respect to the axis of rotation 5, extend, for example, inward in the radial direction.

Each of the sealing legs 17 and 18 has a free end 28 or 29 on its side facing away from the connecting leg 19. The seal 11 has a maximum width B viewed in the seal cross section, namely on its side facing away from the connecting leg 19. The maximum width B corresponds to the maximum distance between the sealing legs 17 and 18 or the maximum distance between the sealing surfaces 15 and 16. The connecting leg 19, on the other hand, has a width b which, for example, can be defined as the mean width or width in the region of its longitudinal center axis 25. The width b is smaller than the width B. Furthermore, the width b of the connecting leg 19 is preferably smaller than or equal to a width of the recess 14 in which the seal 11 is arranged. Also a reverse configuration, as described above, can of course be realized. Here, the width b is greater than the width of the recess 14 or greater than its extension in the axial direction with respect to the axis of rotation 5.

On their side facing away from the connecting leg 19, the sealing legs 17 and 18 are each delimited by a flat surface defined by a straight line 30 or 31, respectively. Seen in section, the straight line 30 is connected to the first sealing surface 15 or a straight line defining it via a curve 32, while it is connected via a curve 33 to an inner surface 34 of the first sealing leg 17 or a straight line defining it. This applies analogously to the second sealing leg 18, with rounded portions 35 and 36 and an inner surface 37 being present. Each of the sealing legs is delimited in section on its side facing the other of the sealing legs 18 or 17 by the respective inner surface 34 or 37 and on the side facing away from the other of the sealing legs 18 or 17 by the respective sealing surface 15 or 16.

For the second sealing leg 18, it is indicated that the inner surface 37 is defined by a first straight line 38 and the sealing surface 16 is defined by a second straight line 39. The two straight lines 38 and 39 and consequently extensions of the sealing surface 16 and the inner surface 37 are angled towards one another, that is to say intersect one another at an angle α. The angle α can in principle be chosen as desired. For example, it is at least 2.5 °, at least 5 °, at least 7.5 ° or at least 10 °. The seal 11 is preferably designed such that the two straight lines 38 and 39 or the sealing surface 16 and the inner surface 37 are angled against each other in the relaxed state of the seal 11, but after assembly of the seal 11 in the gear fluid machine 1 enclose a smaller angle with one another or parallel are arranged to each other.

The seal 11 has a height H in the direction of the plane of symmetry 24 or in a direction perpendicular to the longitudinal center axis 25. This is composed of a height h _{1 of} the connecting leg 19 and a height h _{2 of} the sealing legs 17 and 18. The height h ₁ simultaneously corresponds to a material thickness s _{1 of} the connecting leg 19, i.e. in particular its extent in the plane of symmetry 24 in section. It can clearly be seen that the height h _{2 is} greater than the height h ₁ , for example the height h _{2 being} at least 25%, at least 50%, at least 75% or at least 100% greater than the height h ₁ . Additionally or alternatively, the material thickness s _{1 of} the connecting leg 19 is greater than a material thickness s _{2 of} the sealing legs 17 and 18. In other words, the extension is therefore of the connecting leg 19 in the radial direction with respect to the axis of rotation 5 is greater than the extent of the sealing legs 17 and 18 in the axial direction, for example the material thickness s ₁ is at least 5%, at least 10%, at least 15%, at least 20% or at least 25% greater than the material thickness s ₂ . The ratio between the height H and the width b and / or the width B is preferably selected such that the seal 11 can be removed from the mold without movable mold elements.

The Figure 4 shows a section through a second embodiment of the seal 11. Reference is made in full to the above statements with regard to the first embodiment and only the differences are pointed out below. These are that the free ends 28 and 29 of the sealing legs 17 and 18 are not limited by straight lines 30 and 31, but rather that the free ends 28 and 29 have continuous curves 40 and 41. Each of the curves 40 and 41 starts from the respective sealing surface 15 or 16 and extends to the respective inner surface 34 or 37. The curves 40 and 41 are designed, for example, as circular segments and are dimensioned such that they on the one hand into the sealing surface 15 or 16 and on the other hand run tangentially into the inner surface 34 and 37, respectively.

The Figure 5 shows a schematic representation of the seal 11, it being clear that this has at least a first sealing area 42 and a second sealing area 43, in the embodiment shown here two first sealing areas 42 and two second sealing areas 43. The sealing areas 42 and 43 differ in particular with respect to their curvature. The first sealing area 42 is preferably less curved than the second sealing area 43. If this description only deals with one of the first sealing areas 42 and / or one of the second sealing areas 43, the statements preferably always apply analogously to each of the first sealing areas 42 and / or each of the second sealing areas 43.

The first sealing area 42 merges into the second sealing area 43 via a transition area 44. In particular, such a transition area 44 is provided between each of the first sealing areas 42 and the second sealing areas 43 adjoining them. In the transition area 44 or in each of the transition areas 44, the seal 11 has a bend 45. In the bend 45, a greater curvature is realized in comparison with the first sealing area 42 and the second sealing area 43. The curvature of the seal 11 is preferably greater in the bend 45 than over it the entire first sealing area 42 and / or the entire second sealing area 43 away. Furthermore, it is preferably provided that the curvature of the second sealing area 43 is greater throughout it than in the first sealing area 42. The first sealing area 42 preferably runs straight at least in some areas or even continuously.

The first sealing area 42 differs from the second sealing area 43 in particular with regard to the sealing cross section. The transition area 44 can therefore be designed in such a way that a smooth transition of the two sealing areas 42 and 43 into one another is realized, that is to say there is no abrupt change in the sealing cross-section.

The Figure 6 FIG. 11 shows a section through the seal 11 in the first sealing area 42, indicated in FIG Figure 5 by the cutting mark A. The height h _{1 of} the connecting leg 19 is shown, which corresponds to its material thickness s ₁ . The distance B between the sides of the sealing legs 17 and 18 facing away from one another is also indicated. The seal 11 is shown in its relaxed state.

The Figure 7 FIG. 11 shows a sectional view of the seal 11 in the second sealing region 43, the corresponding point in FIG Figure 5 is indicated by the cutting mark B. The height h _{1 of} the connecting leg 19 and the width B are shown again. It becomes clear that the seal 11 preferably has a greater width B in the second sealing area 43 than in the first sealing area 42. Conversely, however, the height h ₁ for the second sealing area 43 is smaller than for the first sealing area 42.

In other words, the height h _{1 has} a first value in the first sealing area 42 and a second value in the second sealing area 43, the second value being smaller than the first value. Additionally or alternatively, the width of the seal 11 has a first value in the first sealing area 42 and a second value in the second sealing area 43, the second value being greater than the first value.

For example, the height h ₁ in the first sealing area 42 in relation to the height h ₁ in the second sealing area 43 is at least 101%, at least 102%, at least 103%, at least 104% or at least 105%. The ratio mentioned can, however, also be greater and be at least 110%, at least 120%, at least 130%, at least 140% or at least 150%. Additionally or alternatively, the width is B in the first sealing area 42 based on the width B in the second sealing area 43 preferably at most 90%, at most 80%, at most 75%, at most 70%, at most 60% or at most 60% or at most 50%.

In particular, the values for the distance B and the height h _{1 are selected in} such a way that the same spring effect of the seal 11 in the direction of its width B, i.e. when the seal 11 is installed between the machine housing 4 and the axial disk 7 and 8, respectively, is achieved for the sealing areas 42 and 43 results.

The Figure 8 shows a schematic sectional view of an alternative embodiment of the first sealing area 42. It becomes clear that the connecting leg 19 exists at most in an imaginary form and the two sealing legs 17 and 18 are connected to one another over the entire height H of the seal 11 so that they have no unconnected free ends exhibit. In this case, the height h _{2 of} the sealing legs 17 and 18 preferably corresponds to the entire height H. The configuration described can alternatively also be provided in the second sealing area 43. It is important, however, that the shape of the seal 11 described above is present in at least one of the sealing areas 42 and 43, namely with sealing legs 17 and 18 which are connected to one another by the connecting leg 19 and which each have a free end on their connecting leg 19 facing away from the connecting leg 19 Side.

Claims (14)

1. A geared fluid machine (1), having a machine housing (4), a first gearwheel (2) and a second gearwheel (3) which meshes with the first gearwheel (2), wherein the first gearwheel (2) and the second gearwheel (3) are each rotatably mounted in the machine housing (4) with respect to an axis of rotation (5) and are each arranged at least partially contacting by the end faces thereof at least one axial washer (7, 8) arranged in the machine housing (4) with axial play, the same having on its side which faces away from the gearwheels (2, 3) a pressure field (9) surrounded by a circumferential seal (11) which contacts and seals against a first bearing surface (12) of the axial washer (7, 8) on one side thereof, and on the other side contacts and seals against a second bearing surface (13) of the machine housing (4), wherein the seal (11) is particularly at least partially U-shaped when viewed in section, and has a first seal limb (17) lying against the first bearing surface (12), a second seal limb (18) lying against the second bearing surface (13), and a connecting limb (19) connecting the first seal limb (17) and the second seal limb (18), characterized in that the connecting limb (19), when viewed in section, has at least on its side opposite the seal limbs (17, 18) an extension in the axial direction with respect to one of the axes of rotation (5) which is less than the distance between the first bearing surface (12) and the second bearing surface (13) when the axial washer (7, 8) is lying against the machine housing (4).
2. The geared fluid machine according to claim 1, characterized in that the seal (11) is made of a uniform, elastic material, and/or is designed with no support ring.
3. The geared fluid machine according to one of the preceding claims, characterized in that the seal (11), when viewed in section is symmetric with respect to a symmetry plane (24) extending through the connecting limb (19) at a distance from the seal limbs (17, 18).
4. The geared fluid machine according to one of the preceding claims, characterized in that the seal limb (17, 18), when viewed in section and when the seal is in the relaxed state (11), has free ends (28, 29) sharply inclined away from each other in the direction facing away from the connecting limb (19).
5. The geared fluid machine according to one of the preceding claims, characterized in that sides of the free ends (28, 29) which face away from each other when the seal (11) is in the relaxed state have a greater spacing from each other than the first bearing surface (12) and the second bearing surface (13).
6. The geared fluid machine according to one of the preceding claims, characterized in that each of the seal limbs (17, 18), when viewed in section, can be delimited on each of its sides facing the other of the seal limbs (18, 17), respectively, by a first imaginary line (38), and on its other side which is opposite the other seal limb (18, 17) by a second imaginary line (39), wherein the first line (38) and the second line (39) are angled towards each other when the seal (11) is in the relaxed state.
7. The geared fluid machine according to one of the preceding claims, characterized in that the connecting limb (19), when viewed in section, is rectangular and has at least one chamfer or one round edge (20, 21) on its side opposite the seal limbs (17, 18).
8. The geared fluid machine according to one of the preceding claims, characterized in that the connecting limb (19) has an extension in the radial direction, when viewed in section, which is greater than the extension of the first seal limb (17) and/or the extension of the second seal limb (18) in the axial direction.
9. The geared fluid machine according to one of the preceding claims, characterized in that the free ends (28, 29) of the seal limbs (17, 18), when viewed in section, have at least one rounding (40, 41) which is between the first imaginary line (38) and the second imaginary line (39).
10. The geared fluid machine according to one of the preceding claims, characterized in that the seal (11) has at least one first seal region and at least one second seal region, wherein the first seal region and the second seal region have different seal cross-sections.
11. The geared fluid machine according to claim 10, characterized in that the distance (B) of the sides of the free ends (28, 29) of the seal limb (17, 18) which face away from each other, when the seal (11) is in the relaxed state, is of a first value in the first seal region and a second value in the second seal region which is different from the first value.
12. The geared fluid machine according to claim 10 or 11, characterized in that the height of the connecting limb (19) has a first value in the first seal region and has a second value in the second seal region which is different from the first value.
13. The geared fluid machine according to claims 10 to 12, characterized in that the first seal region and second seal region transition into each other via a transition region.
14. The geared fluid machine according to claims 10 to 13, characterized in that the first seal region and the second seal region are connected to each other via a bend, wherein the bend has a greater curvature than the first seal region and the second seal region.

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