gear machine

Abstract

Internal gear machine (1), with a pinion (2) having external teeth (4) and a ring gear (5) mounted eccentrically about a ring gear rotation axis (6) and with respect to the pinion (2), which ring gear has internal teeth (7) meshing partially with the external teeth (4), wherein a housing (11) of the gear machine (1) has a suction connection (19), characterized in that the suction connection (19) has a plurality of suction connection recesses (24) formed at a distance from one another in the housing (11), and a suction connection piece (32) is connected to the suction connection (19), which overlaps the suction connection recesses (24) and has a non-circular flow cross-section on its side facing the housing (11), wherein the flow cross-section of the suction connection piece (32) has larger dimensions in the axial direction on its side facing the housing (11) than on its side facing the housing (11) opposite side,and wherein the suction connection piece (32) has dimensions on its side facing the housing (11) which correspond to an extension of a suction chamber (17) in the axial direction, so that an inner circumferential surface (45) of the suction connection piece (32) is at least partially aligned with inner circumferential surfaces (46) of the suction connection recesses (24).

Description

[0001] The invention relates to a gear machine with a pinion having external teeth and a ring gear mounted eccentrically about a ring gear axis of rotation and with respect to the pinion, which ring gear has internal teeth that mesh partially with the external teeth, or with a first gear having a first external toothing and a second gear that has second external teeth that mesh partially with the first external teeth, wherein a housing of the gear machine has a suction connection.

[0002] The gear machine can be designed, for example, as a gear pump or as a gear motor. It can also be designed as an internal gear machine or as an external gear machine, so that the gear machine can be an internal gear pump, internal gear motor, external gear pump, or external gear motor. In the case of an internal gear machine, the gear machine has the pinion with the external teeth and the ring gear that is mounted eccentrically around the ring gear axis of rotation and with respect to the pinion and has internal teeth that partially mesh with the external teeth. If the gear machine is designed as an external gear machine, it has the first gear with the first external teeth and the second gear with the second external teeth that partially mesh with the first external teeth.Regardless of whether it is designed as an internal gear machine or as an external gear machine, the housing of the gear machine has the suction connection.

[0003] In summary, the invention relates, on the one hand, to a gear machine comprising a pinion having external teeth and a ring gear mounted eccentrically about a ring gear rotation axis and with respect to the pinion, which ring gear has internal teeth that mesh partially with the external teeth, wherein a housing of the gear machine has a suction port. On the other hand, the invention relates to a gear machine comprising a first gear having a first external toothing and a second gear that has second external teeth that mesh partially with the first external toothing, wherein a housing of the gear machine has a suction port.

[0004] The following will only look at the internal gear machine as an example. However, the explanations are always easily transferable to the external gear machine. In the case of the internal gear pump, the pinion of the internal gear machine is subjected to a rotary motion, which exerts a conveying effect on a fluid. If, on the other hand, the internal gear machine is designed as an internal gear motor, fluid is supplied to it, which sets the pinion in rotary motion. In this way, a torque is provided at the pinion, which can be tapped. The following will only look at the internal gear pump in more detail. However, the explanations are always easily transferable to the internal gear motor.

[0005] The internal gear machine has the pinion and the ring gear as essential components. For example, the pinion and the ring gear are arranged, in particular rotatably mounted, in a housing of the internal gear machine. The pinion is rotatably mounted about a pinion axis of rotation, the ring gear about a ring gear axis of rotation. To achieve the eccentric mounting of the ring gear with respect to the pinion, the ring gear axis of rotation is arranged parallel and spaced from the pinion axis of rotation. 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 their respective axis of rotation. The outer diameter of the pinion and the inner diameter of the ring gear are selected such that the outer teeth of the pinion only engage with a portion of the internal teeth of the ring gear.

[0006] The pinion is arranged, for example, on a drive shaft of the internal gear machine, in particular is connected to it in a rotationally fixed manner. The pinion can be driven via the drive shaft and set in rotation about the pinion axis of rotation. Because the external teeth mesh with the internal teeth, the rotational movement of the pinion is also impressed on the ring gear. In the case of the internal gear pump, the pinion is driven directly by the drive shaft, while the ring gear is driven only indirectly via the pinion. Both the external and internal teeth each have a large number of teeth and spaces between the teeth. In the case of the internal gear pump, the pumping effect is achieved through the meshing of the external and internal teeth.

[0007] When observing any tooth of the pinion during a complete rotation of the pinion, this tooth temporarily engages with a tooth space in the internal gearing. Before the tooth engages with the tooth space, the fluid is present in the latter. Through engagement, the fluid is preferably pumped into a pressure chamber of the internal gear pump. The pressure chamber is formed, for example, in the housing of the internal gear pump. If the internal gear machine is designed as an internal gear motor, the fluid flows from the pressure chamber towards a suction chamber of the internal gear machine, driving the pinion and the ring gear. In this respect, the internal gear motor represents the kinematic inverse of the internal gear pump.

[0008] From the prior art, for example, the document DE 1 403 899 is known. This describes a gear pump with an internally toothed ring gear and an externally toothed pinion meshing with the ring gear, as well as a crescent-shaped filler arranged between the two gears, wherein one or more bearing shells, at least one pressure-side bearing shell, are arranged between the outer circumferential surface of the ring gear and the housing bore wall surrounding it, the latter having, on its outer side facing away from the ring gear outer circumferential surface, an elongated outer pressure field extending in the circumferential direction and connected to the pump pressure side, and on its inner side facing the ring gear, a pressure relief field which, with regard to its radially effective area, is smaller than the outer pressure field and is in the form of a circumferentially extending recess in the bearing shell.The pressure field on the outside of the control shell should also exceed the relief pressure field on its inside in the axial direction.

[0009] It is now an object of the invention to propose an internal gear pump which has advantages over known internal gear pumps, in particular enabling a higher fluid throughput.

[0010] This is achieved according to the invention with an internal gear machine having the features of claim 1. It is provided that the suction connection has a plurality of suction connection recesses formed at a distance from one another in the housing. A flow connection, preferably a permanent flow connection, to the suction chamber is established via the suction connection, which is formed on or in the housing. If the internal gear machine is designed as an internal gear pump, which is assumed in the following explanations, the fluid to be pumped is provided to the internal gear machine via the suction connection. It is pointed out again that all embodiments described in this description can of course be easily transferred to a design of the internal gear machine as an internal gear motor.

[0011] With the help of the multiple suction connection recesses, the total flow cross-section of the suction connection can be increased, in particular compared to an embodiment in which only a single suction connection recess is provided. For example, it is provided that a fluid line is connected directly to the suction connection. The fluid line can have a constant or essentially constant flow cross-section and / or a constant flow cross-sectional area in the direction of flow of the fluid. Insofar as the flow cross-section is mentioned in this description, the shape of the flow cross-section, its dimensions in at least one direction or its area, i.e. the flow cross-sectional area, can be meant. For the sake of simplicity, not all possibilities are referred to. Rather, they arise from the context.

[0012] It can be provided that the fluid line is connected to the internal gear machine in such a way that it is directly fluidically connected to a plurality of suction connection recesses, so that a fluid connection from the fluid line to the suction chamber of the internal gear machine is established via the plurality of suction connection recesses. Of course, it can also be provided that the fluid supply to the internal gear machine is provided via a plurality of fluid lines, wherein preferably a separate fluid line is assigned to each suction connection recess. Accordingly, the internal gear machine can be supplied with fluid via a plurality of fluid lines, so that an overall higher fluid throughput is realized.

[0013] In a further embodiment of the invention, the ring gear has radial openings that pass through an inner circumferential surface and an outer circumferential surface of the ring gear. The radial openings through which the fluid can escape from the inter-tooth spaces or through which it can enter the inter-tooth spaces are provided in the ring gear. Preferably, each of the inter-tooth spaces is assigned such a radial opening. The radial opening opens into one of the inter-tooth spaces on its radially inner side and thus passes through the inner circumferential surface of the ring gear. On its radially outer side, the radial opening passes through the outer circumferential surface of the ring gear.

[0014] In the case of the internal gear pump, due to the above-described engagement of the tooth in the inter-tooth space, the fluid is pumped through the radial opening associated with the inter-tooth space toward the outer peripheral surface of the ring gear and preferably into the pressure chamber of the internal gear machine. The pressure chamber is formed, for example, in the housing of the internal gear machine. However, a variant of the internal gear machine without radial openings is of course also feasible.

[0015] In a further preferred embodiment of the invention, a crescent-shaped filler piece is arranged between the feed pinion and the ring gear. The filler piece is therefore provided in the feed chamber. The filler piece preferably rests on the one hand against the ring gear and on the other hand against the feed pinion. The filler piece can be designed as a single piece and / or in multiple parts. The filler piece serves in particular to prevent backflow of the fluid towards the feed chamber. The feed chamber - which can also be referred to as the suction chamber - is located in the ring gear or, viewed in cross-section, is jointly delimited by the internal toothing of the ring gear and the external toothing of the pinion. The suction connection preferably opens into the feed chamber, in particular directly.

[0016] In a further embodiment of the invention, each of the suction connection recesses has an opening on the outside of the housing, which is overlapped by a suction connection piece connected to the suction connection. The internal gear machine has the suction connection piece, which is fluidically connected to the suction connection. The flow connection into the suction chamber of the internal gear machine is thus provided via the suction connection piece and the suction connection. The suction connection and the suction connection piece are fluidically directly connected to one another, i.e. they merge directly into one another. The suction connection piece can be a separate element and can be fastened to the housing, preferably in a form-fitting and / or material-fitting manner. The form-fitting fastening is understood to mean, in particular, a screw fastening. The material-fitting fastening can be realized by welding, soldering, or gluing.Of course, the suction connection piece can alternatively also be designed in one piece and / or made of the same material as the housing, i.e. in particular can be manufactured together with the housing.

[0017] For example, within the scope of an advantageous embodiment of the invention, the suction connection piece has an inlet opening on its side facing away from the housing, which has a circular flow cross-section. The fluid line can be directly connected to this inlet opening, so that the fluid can flow from the fluid line through the inlet opening into the suction connection piece. In the case of the internal gear motor, the inlet opening can of course be referred to as the outlet opening.

[0018] The suction connection piece can be used to increase the fluid throughput of the internal gear machine. In particular, the flow of fluid through the suction connection into the suction chamber is improved, and the resulting flow resistance is reduced. For this purpose, the suction connection piece can be flow-optimized and, for example, have a larger or smaller flow cross-section or a larger or smaller flow cross-sectional area on its side facing the housing, in particular on its side adjacent to the housing, than on its side facing away from the housing.The flow cross-section of the suction connection piece or its area increases or decreases, for example, in the direction of the housing of the internal gear machine, wherein the increase or decrease occurs at least in some areas, in particular continuously along the entire flow path of the suction connection piece, and / or at least in some sections in the form of a jump and in this respect discontinuously, in particular by means of a single change in the flow cross-section along the flow path.

[0019] In a conventional internal gear machine, for example, a fluid line with a constant flow cross-section in terms of shape and area in the direction of fluid flow is provided directly to the suction port. In the internal gear machine described here, however, the fluid line is to be connected to the suction port, namely on the side facing away from the housing. A flow connection between the fluid line and the suction port is thus only indirectly established via the suction port.

[0020] Each of the multiple suction connection recesses is assigned a respective opening on the outside of the housing, in which opening the respective suction connection recess extends through an outside of the housing or an outer peripheral surface of the housing. The respective suction connection recess is thus in flow communication with the suction connection nozzle via the opening. The suction connection nozzle is now configured such that it overlaps several, in particular all, of the openings of the multiple suction connection recesses, in particular completely overlaps them, thus in particular sealing them off from the outside environment. The flow cross-section of the suction connection nozzle on its side facing the housing is dimensioned accordingly for this purpose.

[0021] Particularly preferably, the suction connection recess has a flow cross-section which, in terms of its area, is at least as large as the largest flow cross-section of the suction connection piece in the flow direction and / or as the flow cross-section of the inlet opening of the suction connection piece. However, the flow cross-section of the suction connection recess or its area is particularly preferably larger. The plurality of suction connection recesses preferably have a total flow cross-section or a total flow cross-sectional area which corresponds at least to the largest flow cross-section of the suction connection piece in the flow direction or to the flow cross-section of the inlet opening or its flow cross-sectional area, but is preferably larger.The total flow cross-section corresponds to the sum of the flow cross-sections of all suction connection recesses overlapped by the suction connection nozzle.

[0022] In a further preferred embodiment of the invention, one of the suction connection recesses has a longitudinal central axis, wherein the longitudinal central axis is perpendicular to an imaginary plane accommodating the external mouth opening or is angled with respect to this plane. The longitudinal central axis is in this case a straight line. Each of the plurality of suction connection recesses has such a longitudinal central axis. The longitudinal central axis of at least one of the suction connection recesses, preferably the longitudinal central axes of a plurality of suction connection recesses, in particular of all suction connection recesses, are now perpendicular to the respective imaginary plane or are angled with respect to this plane.

[0023] The longitudinal central axis or the longitudinal central axes preferably run straight over the entire extent of the respective suction connection recess. The imaginary plane is defined by the external mouth opening at which the corresponding suction connection recess extends through the outer circumferential surface of the housing. Preferably, one edge of the mouth opening lies completely in the plane. For example, an angle of 90° should exist between the longitudinal central axis and the plane. Alternatively, a different angle can be provided, in particular an angle that is greater than 0° and less than 90°. In particular, the angle is at least 10°, at least 20°, at least 30°, at least 45° or exactly 45°. In this respect, an oblique arrangement of the respective suction connection recess is provided.

[0024] A further development of the invention provides that the longitudinal center axis of at least one of the suction connection recesses runs at a distance from the ring gear or intersects its outer circumferential surface at a point which has a distance from an end face of the ring gear which, based on the dimensions of the ring gear in the axial direction, amounts to at most 1%, at most 2%, at most 2.5%, at most 3%, at most 4%, at most 5%, at most 7.5%, or at most 10%. This applies to at least one of the suction connection recesses, preferably several of the suction connection recesses, particularly preferably to each of the suction connection recesses.

[0025] The longitudinal center axis of the suction connection recess should not extend through the ring gear, particularly when viewed in longitudinal section. Alternatively, the point at which the longitudinal center axis or the corresponding straight line intersects the outer circumferential surface of the ring gear should be positioned relatively far to the outside. The distance to the end face of the ring gear closest to the point should be one of the specified values, but no more than 10%, based on the dimensions of the ring gear in the axial direction. With this type of arrangement or orientation of the suction connection recess, a lateral flow of the fluid past the ring gear is promoted - viewed in the axial direction - so that a higher fluid throughput can be achieved.

[0026] In a preferred further embodiment of the invention, at least one of the suction connection recesses is designed as a stepped recess. This means that the suction connection recess has different flow cross-sections along its flow path, with regard to shape and / or area. In a first section, the suction connection recess therefore has a first flow cross-section and in a second section a second flow cross-section, wherein the second flow cross-section is different from the first flow cross-section. For example, the flow cross-section of the suction connection recess is larger on its side associated with the suction connection piece than on its side facing the suction chamber.

[0027] With such a configuration of the suction connection recess, the cross-section of the suction connection recess can be enlarged while simultaneously maintaining a control edge of the housing. The first section can be arranged coaxially with the second section. However, an eccentric arrangement is also possible. In this case, the longitudinal center axis described above is preferably defined by the section located furthest outward in the radial direction.

[0028] A preferred further embodiment of the invention provides that - viewed in longitudinal section - a web, in particular a housing web, located in the axial direction between two of the suction connection recesses, has at least one chamfer on the outside, in particular a chamfer on each side. The chamfer is understood to be an inclined surface that is flat, i.e. lies entirely in an imaginary plane. This imaginary plane should be at an angle of greater than 0° and less than 90° with respect to the ring gear axis of rotation. For example, the angle is at most 80°, at most 70°, at most 60°, at most 50°, or at most 45°, for example exactly 45°.

[0029] Such a design significantly reduces the flow resistance exerted on the fluid when it flows in. The web, on which the at least one chamfer is present, lies between two of the suction connection recesses, thus separating them from one another in terms of flow. The web is preferably a component of the housing and is therefore present as a housing web. Particularly preferably, a chamfer is produced on both sides of the web - viewed in longitudinal section - and these chamfers are particularly arranged at the same angle to the ring gear axis of rotation. In this respect, the web is roof-shaped in the direction of the suction connection nozzle. Of course, the web can also have a different shape. For example, viewed in longitudinal section, it is in the shape of a segment of a circle, for example semicircular.

[0030] In a further preferred embodiment of the invention, it is provided that at least one of the suction connection recesses has a flow cross-section that is round, oval, stadium-shaped or polygonal, in particular rectangular. This can be the case for at least one of the suction connection recesses, preferably several of the suction connection recesses, in particular each of the suction connection recesses. For example, the respective suction connection recess has the flow cross-section over its entire flow path. The flow cross-section can be round, oval, stadium-shaped or polygonal, in particular rectangular and / or quadrangular. The stadium-shaped flow cross-section is understood to be a flow cross-section that is delimited by two opposite parallel straight lines and two circular arcs connecting these.The rectangular flow cross-section is framed by several perpendicular straight lines, whereby corners where the straight lines meet can of course be rounded.

[0031] In a preferred further embodiment of the invention, the flow cross-section of the side of the suction connection piece facing the housing is round, oval, stadium-shaped, or polygonal, in particular rectangular and / or square. The suction connection piece therefore preferably has one of the aforementioned shapes on its side enclosing the suction connection recesses. These are defined according to the above explanations, so reference is made to them.

[0032] A further development of the invention provides that the suction connection piece has a flow cross-section on its side facing the housing which has larger dimensions, at least in the axial direction, than the ring gear. This means that the jet of fluid flowing into the suction chamber of the internal gear machine is widened at least in the axial direction before flowing through the suction connection or the at least one suction connection recess, so that the fluid has an extension in the axial direction which is greater than the extension of the ring gear in the same direction. Of course, despite the expansion in the axial direction, the flow cross-section or its area in the flow direction or in the direction of the housing can remain the same or even become smaller.

[0033] It is particularly preferably provided that - seen in longitudinal section - an inner circumferential surface of the suction connection piece on its side facing the housing is aligned at least in sections with an inner circumferential surface of at least one of the suction connection recesses, in particular several of the suction connection recesses, so that the overflow from the suction connection piece into the at least one suction connection recess can take place with low flow resistance.

[0034] Finally, a further preferred embodiment of the invention provides that the flow cross-section of the suction connection piece remains constant along its flow path, or that the flow cross-section of the suction connection piece tapers in the direction facing away from the housing, at least in the axial direction, in particular only in the axial direction. This is provided, for example, if the fluid line via which fluid is to be supplied to or discharged from the internal gear machine has a smaller flow cross-section than the at least one suction connection recess or the plurality of suction connection recesses in total.Thus, the suction connection piece has a first flow cross-section at its end facing the housing and a second flow cross-section at its end facing away from the housing, wherein the second flow cross-section is smaller than the first flow cross-section in terms of its area and / or at least one dimension. In particular, the second flow cross-section is smaller than the first flow cross-section only in the axial direction.

[0035] The invention further relates to a gear machine, in particular according to the above embodiments, with a pinion having external teeth and a ring gear mounted eccentrically about a ring gear rotation axis and with respect to the pinion, which ring gear has internal teeth that mesh partially with the external teeth, or with a first gear having a first external toothing and a second gear that has second external teeth that mesh partially with the first external teeth, wherein a housing of the gear machine has a suction connection. It is provided that a suction connection piece is connected to the suction connection, which has a non-circular flow cross-section on its side facing the housing.

[0036] The gear unit described here can also be designed as an internal gear unit or an external gear unit. Reference is made to the explanations above for this purpose. However, only the internal gear unit will be discussed in more detail purely as an example. The suction connection piece with the non-circular flow cross-section can be implemented in addition to or as an alternative to the above-described embodiments and refinements of the gear pump. Their advantages have already been discussed in detail, so reference is made to the above explanations in this regard.

[0037] The suction connection connected to the suction connection piece can only have a single suction connection recess.

[0038] The suction connection recess has, for example, a flow cross-section that can be selected arbitrarily, but is preferably non-circular. For example, the suction connection recess has a flow cross-section that is oval, stadium-shaped, or polygonal, in particular square. Of course, the suction connection connected to the suction connection piece can alternatively have multiple suction connection recesses, in particular at least two suction connection recesses. The multiple suction connection recesses are formed spaced apart from one another in the housing.

[0039] The invention will be explained in more detail below with reference to the exemplary embodiments shown in the drawings, without limiting the invention. In the drawings: Fig. 1 a cross-sectional view of a first embodiment of an internal gear machine, Fig. 2 a cross-sectional view of a second embodiment of the internal gear machine, Fig. 3 a cross-sectional view of a third embodiment of the internal gear machine, Fig. 4 a longitudinal sectional view of a first variant of the first embodiment, Fig. 5 a longitudinal sectional view of a second variant of the first embodiment, Fig. 6 a longitudinal sectional view of a third variant of the first embodiment, Fig. 7 is a plan view of a suction port of the internal gear pump in the first embodiment, Fig. 8 a plan view of the suction connection in an alternative design, as well as Fig. 9 a plan view of the suction connection in a further alternative embodiment.

[0040] The Fig. Figure 1 shows a cross-section through a gear machine 1, which in the embodiment shown here is designed as an internal gear machine, in particular as an internal gear pump. The following will only discuss such an embodiment. However, the described features are readily transferable to an alternative embodiment of the gear machine 1 as an internal gear motor, external gear pump, or external gear motor.

[0041] The internal gear pump 1 has a pinion 2, which is rotatably mounted about a pinion rotation axis 3 and has external teeth 4 with a plurality of teeth and tooth spaces. Furthermore, the internal gear pump 1 has a ring gear 5, which is rotatably mounted about a ring gear rotation axis 6. The ring gear rotation axis 6 is arranged parallel to the pinion rotation axis 3 and spaced apart. The ring gear 5 is thus mounted eccentrically with respect to the pinion 2.

[0042] The ring gear 5 completely accommodates the pinion 2 and has an internal toothing 7 with a plurality of teeth and tooth spaces. The internal toothing 7 meshes partially with the external toothing 4. In particular, the external toothing 4 engages at least partially with the internal toothing 7 in an engagement region 8. It can be seen that each tooth space of the internal toothing 7 is assigned a radial opening 9, with only a portion of the radial openings 9 being identified. The radial openings 19 are preferably designed as radial bores and each have a longitudinal center axis that intersects the ring gear rotation axis 6, in particular is perpendicular to it.

[0043] The pinion 2 is preferably arranged on a drive shaft 10, in particular connected thereto in a rotationally fixed manner. The pinion 2 is also mounted in a housing 11 of the internal gear pump 1 by means of the drive shaft 10. The bearing of the ring gear 5, on the other hand, is realized by means of a first bearing point 12 and a second bearing point 13. To form the bearing points 12 and 13, the housing 11 has a bearing area 14 and 15, respectively. The bearing area 14 is preferably adapted to an outer circumferential surface 16 of the ring gear 5, thus having the same curvature, in particular in the circumferential direction with respect to the ring gear rotation axis 6.

[0044] In the area of the bearing points 12 and 13, the ring gear 5 rests with its outer circumferential surface 16 against the bearing areas 14 and 15 of the housing 11 and is thus securely held in the radial direction. Preferably, one of the bearing points 12 and 13, here bearing point 13, is located at an angular position at which the external toothing 4 of the pinion 2 fully engages the internal toothing 7 of the ring gear 5. Accordingly, the ring gear 5 is urged toward the bearing point 13 by the pinion 2 or the fluid pressure acting between the pinion 2 and the ring gear 5 and is reliably held there.

[0045] Viewed in the circumferential direction, a suction chamber 17 and a pressure chamber 18 are located between the bearing points 12 and 13. A suction connection 19 opens into the suction chamber 17, and a pressure connection 20 opens into the pressure chamber 18. The suction connection 19, like the pressure connection 20, is formed in the housing 11. The fluid to be pumped can be made available to the internal gear pump 1 via the suction connection 19, while the pumped fluid can be made available by the internal gear pump 1 at the pressure connection 20 and can be drawn from or removed from this. The fluid to be pumped can now pass from the suction chamber 17 into a pumping chamber 21 provided in the ring gear 5. A filler piece 22, which is preferably sickle-shaped, can optionally be provided in this chamber. The filler piece 22 can be formed in one piece or in multiple parts. In particular, it lies in an angular range in which the first bearing point 12 is formed on the housing 11.Preferably, it extends beyond this angular range.

[0046] The fluid located in the delivery chamber 21 reaches the interdental spaces of the external gearing 4 and the internal gearing 7 and is carried along by them in the direction of rotation. The direction of rotation is indicated here by the arrow 23. Due to the gradual engagement of the external gearing 4 with the internal gearing 7 in the direction of rotation, the fluid is forced from the interdental spaces through the radial openings 9 and out of the ring gear 5. The fluid thereby reaches the pressure chamber 18 and can then be removed via the pressure connection 20. The radial openings 19 are arranged such that each of the radial recesses 9 overlaps with the pressure chamber 18 in at least one rotational angular position of the ring gear 5, thus establishing a flow connection between the respective radial opening 9 and the pressure chamber 18.

[0047] In the embodiment shown here, the suction connection 19 is preferably formed by a plurality of suction connection recesses 24 provided in the housing 11. In the illustration shown here, only one of the suction connection recesses 24 is visible. Of course, alternatively, only a single suction connection recess 24 can be provided. The suction connection recesses 24 each have an outlet opening 25 on the outside of the housing. In the embodiment shown here, a respective longitudinal center axis 26 of the suction connection recesses 24, which is straight, is perpendicular to the outlet opening 25 or an imaginary plane receiving the outlet opening 25.

[0048] The Fig. Figure 2 shows the internal gear pump 1, with the suction connection recesses 24 in a second embodiment. Reference is generally made to the above explanations, and only the differences will be discussed below. It is clearly visible that the longitudinal central axis 26 of the suction connection recess 24 shown here is not perpendicular to the outlet opening 25 or the plane defined by it, but rather is angled relative to it. For example, the longitudinal central axis 26 forms an angle with the plane, which is indicated here by the double arrow 27.

[0049] The angle is greater than 0° and less than 90°. This angled orientation of the suction connection recess 24 allows its flow cross-section or its flow cross-sectional area to be significantly increased compared to the embodiment described above. This can also be implemented for the other suction connection recesses 24.

[0050] The Fig. Figure 3 shows the internal gear pump 1 with suction connection recesses 24 in a third embodiment. Reference is again made to the above explanations, and only the differences will be discussed below. The illustrated suction connection recess 24, or its longitudinal central axis 26, is angled relative to the orifice 25, or the plane defined by it, analogous to the second embodiment described above. To further increase its flow cross-section, or its area, it is designed as a stepped recess, thus having different flow cross-sections along its longitudinal central axis 26.

[0051] For example, on its side facing the suction chamber 17, it has a cross-section or diameter indicated by the double arrow 28, while on its side facing away from the pressure chamber 18, it has a flow cross-section or diameter indicated by the double arrow 29. The first flow cross-section is smaller in area than the second flow cross-section. In this way, the bearing area 5 is not reduced in size compared to the second embodiment explained above, so that a control edge 30 is retained.

[0052] The Fig. Figure 4 shows a longitudinal section of the internal gear pump 1 with the suction port 19 of the first embodiment. The corresponding section direction is shown in Fig. 1 by the section mark A. It is clear that there are several suction connection recesses 24, which are arranged at a distance from one another in the axial direction with respect to the ring gear rotation axis 6. They are separated - viewed in longitudinal section - by a web 31, which is preferably a component of the housing 11 and can therefore also be referred to as a housing web. The suction connection 19 is therefore not formed by just a single suction connection recess 24, but rather by several suction connection recesses 24 together. In the embodiment shown here, the web 31 is rectangular when viewed in longitudinal section.

[0053] To nevertheless enable a simple fluidic connection of a fluid line (not shown here) to the internal gear pump 1 or the suction connection 19, a suction connection piece 32 can be provided, which is arranged on the housing 11, in particular is fastened thereto. For example, at least one seal 33, in particular in the form of a sealing ring, is present between the suction connection piece 32 and the housing 11. The seal 33 preferably completely encompasses the flow cross-section of the suction connection piece 32 on its side facing the housing 11.

[0054] It is clearly evident that the suction connection piece 32 has a flow cross-section on its side facing the housing which, at least or only in the axial direction (indicated by the double arrow 34), has larger dimensions than a flow cross-section on its side facing away from the housing 11, the dimensions of the latter flow cross-section being shown by the double arrow 35. In other words, it is particularly provided that the flow cross-section of the suction connection piece 32 has larger dimensions in the axial direction on its side facing the housing 11 than on its side facing away from the housing. Of course, a flow cross-sectional area of the suction connection piece 32 can be constant or have a constant absolute value despite the change in the dimensions of the flow cross-section along a flow direction.

[0055] It is also clear that the housing 11 is made up of several parts and has a housing element 36 and bearing covers 37 and 38. The housing element 36 preferably completely surrounds the ring gear 5 in the circumferential direction and has a greater extension in the axial direction with respect to the ring gear rotation axis 6 than the ring gear 5. The bearing covers 37 and 38 are arranged on the housing element 36 on the opposite sides in the axial direction and close off its ends. Bearings 39, for example plain bearings or roller bearings, for the drive shaft and thus the pinion 2 are preferably arranged in the bearing covers 37 and 38. The bearing arrangement of the ring gear 5 in the radial direction has already been discussed above.

[0056] The bearing of the ring gear 5 in the axial direction is achieved by means of second bearing elements 40 and 41, which are arranged in the axial direction on opposite sides of the ring gear and can also be referred to, for example, as axial disks. The bearing elements 40 and 41 are arranged in the axial direction between the ring gear 5 and the housing 11, in the exemplary embodiment shown here between the ring gear 5 and the bearing cover 37 or 38. A spring element 42 is provided between the housing 11 and each of the bearing elements 40 and 41, which urges the respective bearing element 40 or 41 in the direction of the ring gear 5.

[0057] The spring element 42 can, for example, be in the form of a seal, thus simultaneously having a sealing effect. Additionally, a flow aperture 43 can be present in each of the bearing elements 40 and 41, which completely penetrates the respective bearing element 40 or 41 in the axial direction. Via the flow aperture 43, the fluid present in the pressure chamber 18 can exert a compressive force in the axial direction between the housing 11 and the respective bearing element 40 or 41, thereby providing additional support for the bearing element 40 or 41 in the axial direction.The pressure equalization achieved due to the flow breakthrough 43 between the opposite sides of the bearing element 40 and 41, respectively, has the effect that the spring element 42 is not compressed by the fluid pressure present in the pressure chamber 18, so that by means of the spring element 42 a substantially constant contact pressure of the bearing elements 40 and 41 on the ring gear 5 is always achieved.

[0058] The bearing elements 40 and 41 are preferably dimensioned such that, in the axial direction, on each side of the ring gear 5 in the suction chamber 17, distances remain between the end faces of the ring gear 5 and the housing 11, which are designated here by I3. The ring gear 5 has an extension I1 in the axial direction that is smaller than an extension I2 of the suction chamber 17 in the axial direction. Thus, the fluid can easily pass from the suction chamber 17 into the delivery chamber 21 because, in the suction chamber 17, there is a flow path 44 on each side in the axial direction next to the ring gear 5, via which flow path a flow connection is established between the suction chamber 17 and the delivery chamber 21.Particularly preferably, the suction connection piece 32 has dimensions on its side facing the housing 11 which correspond to the extension I2, so that an inner circumferential surface 45 of the suction connection piece 32 is at least partially aligned with inner circumferential surfaces 46 of the suction connection recesses 24.

[0059] The Fig. 5 shows a longitudinal sectional view of the internal gear pump 1, showing a second variant of the web 31. With regard to the further design, reference is made in full to the above explanations. The web 31 is no longer rectangular, but rather is provided with chamfers 47 on the outside, for example on its side facing the suction connection piece 32, so that two flat inclined surfaces are formed. The chamfers 47 have the same angle of attack, so that an isosceles triangular shape is present when viewed in longitudinal section. By designing the web 31 in this way, the fluid is deflected outwards in the axial direction, so that it is guided in the direction of the inflow paths 44. The overflow of the fluid from the pressure chamber 18 into the delivery chamber 21 along the inflow paths 44 is thus significantly improved, in particular, there is less flow resistance.

[0060] The Fig. 6 shows a longitudinal sectional view of the internal gear pump 1, wherein the suction connection 19 is designed in an alternative variant. According to the above explanations, the web 31 has the two bevels 47. At the same time, however, the flow cross-section of the suction connection piece 32 or its area on its side facing the housing 11 can be smaller than in the embodiment described above. In order to nevertheless realize an inflow of the fluid into the internal gear pump 1 with low flow resistance, the longitudinal central axes 26 of the suction connection recesses 24 are arranged inclined with respect to their respective mouth opening 25, thus each enclosing an angle with the latter which is greater than 0° and less than 90°. The angle is particularly preferably 45°.

[0061] It can be provided that the longitudinal center axis 26 does not intersect the ring gear 5 or its outer circumferential surface 16. However, if this is the case, as shown here, the distance of a point 48 at which the respective longitudinal center axis 26 intersects the outer circumferential surface 16 of the ring gear 5 should have a distance from the nearest end face 49 of the ring gear 5 that, based on the dimensions of the ring gear 5 in the axial direction, amounts to a maximum of 10%. Even with such an embodiment, the fluid is guided in the direction of the inflow paths 44 with a simultaneous low pressure loss.

[0062] The Fig. 7 shows a plan view of a region of the internal gear pump 1. The pressure connection 20 with the suction connection recesses 24 and the respective longitudinal center axis 26 can be seen. The ring gear 5 can also be seen through the suction connection recesses 24. It is clear that the suction connection 19 has a greater overall extension in the axial direction than the ring gear 5. The suction connection nozzle 32 is also shown in dashed lines. This has an inlet opening 50 which is preferably round in cross-section. The end of the suction connection nozzle 32 facing the housing 11, in contrast, is stadium-shaped. The flow cross-sectional area of the inlet opening can be larger, smaller, or equal to the flow cross-sectional area at the end of the suction connection nozzle 32 facing the housing 11.

[0063] The Fig. Figure 8 shows a plan view of the internal gear pump 1, wherein the suction connection 19 and the suction connection nozzle 32 have an alternative shape. Reference is generally made to the above explanations. The suction connection recesses 24 shown here are rectangular, with their edges preferably rounded. Of course, however, hard edges can also be formed. In order to completely overlap both suction connection recesses 24, the suction connection nozzle 32 also has a rectangular flow cross-section on its side facing the housing 11, while the inlet opening 50 remains round.

[0064] The Fig.9 shows a further plan view of the internal gear pump 1, wherein the suction connection 19 and the suction connection nozzle 32 are designed in a third variant. Reference is again made to the above explanations. The difference from the second variant described above is merely that the web 31, by which the suction connection recesses 24 are separated from one another in the axial direction with respect to the ring gear rotation axis 6, has the chamfers 47 described above, so that the web 31 has an edge 51 on its side facing the suction connection nozzle 32, which edge is preferably arranged centrally with respect to the suction connection nozzle 32 in the axial direction.

Claims

[1] Internal gear machine (1), with a pinion (2) having an external toothing (4) and a ring gear (5) mounted eccentrically about a ring gear axis of rotation (6) and with respect to the pinion (2), which ring gear has an internal toothing (7) meshing partially with the external toothing (4), wherein a housing (11) of the gear machine (1) has a suction connection (19), characterized byin that the suction connection (19) has a plurality of suction connection recesses (24) formed at a distance from one another in the housing (11), and a suction connection piece (32) which extends over the suction connection recesses (24) and has a non-circular flow cross-section on its side facing the housing (11) is connected to the suction connection (19), the flow cross-section of the suction connection piece (32) having larger dimensions in the axial direction on its side facing the housing (11) than on its side facing away from the housing (11), and the suction connection piece (32) having dimensions on its side facing the housing (11) which correspond to an extension of a suction chamber (17) in the axial direction, so that an inner circumferential surface (45) of the suction connection piece (32) is at least partially aligned with inner circumferential surfaces (46) of the suction connection recesses (24). [2] Internal gear machine according to claim 1, characterized by that each of the suction connection recesses (24) has an opening point (25) on the outside of the housing, which is overlapped by a suction connection piece (32) connected to the suction connection (19). [3] Internal gear machine according to one of the preceding claims, characterized by that at least one of the suction connection recesses (24) has a longitudinal central axis (26), wherein the longitudinal central axis (26) is perpendicular to an imaginary plane receiving the outer mouth opening (25) or is angled with respect to this. [4] Internal gear machine according to one of the preceding claims, characterized bythat the longitudinal center axis (26) of at least one of the suction connection recesses (24) runs at a distance from the ring gear (5) or intersects its outer circumferential surface (16) at a point (48) which is at a distance from an end face (49) of the ring gear (5) which, based on the dimensions of the ring gear (5) in the axial direction, is at most 10%. [5] Internal gear machine according to one of the preceding claims, characterized by that at least one of the suction connection recesses (24) is designed as a stepped recess. [6] Internal gear machine according to one of the preceding claims, characterized by that - seen in longitudinal section - a web (31), in particular a housing web, present in the axial direction between two of the suction connection recesses (24), has at least one chamfer (47) on the outside, in particular a chamfer (47) on each side. [7] Internal gear machine according to one of the preceding claims, characterized bythat at least one of the suction connection recesses (24) has a flow cross-section which is round, oval, stadium-shaped or polygonal, in particular rectangular. [8] Internal gear machine according to one of the preceding claims, characterized by that the flow cross-section of the side of the suction connection piece (32) facing the housing (11) is round, oval, stadium-shaped or polygonal, in particular rectangular. [9] Internal gear machine according to one of the preceding claims, characterized by that the suction connection piece (32) has, on its side facing the housing (11), a flow cross-section which has larger dimensions, at least in the axial direction, than the ring gear (5).

Images