DE102016103902A1 - Rotor arrangement for a pump and pump unit - Google Patents

Abstract

The present invention initially relates to a rotor assembly for a pump (01); For example, for a ring gear machine in a pump unit. The rotor assembly according to the invention comprises a rotor (09) for conveying a medium. The rotor (19) has an opening (18), with which it sits non-rotatably on a drive shaft (08). According to the invention, the rotor (09) can be tilted about any axis perpendicular to the drive shaft (08) at an axial position of the drive shaft (08) relative to the drive shaft (08). Furthermore, the invention relates to a pump unit, which comprises the rotor assembly according to the invention.

Description

The present invention initially relates to a rotor assembly for a pump, for example for a ring gear machine in a pump unit. Furthermore, the invention relates to a pump unit, which comprises the rotor assembly according to the invention.

From the prior art pumps are known in which a gear pump is designed for conveying a medium. Such gear pumps are designed for example as a toothed ring machine, which is also referred to as a gerotor. An inner toothed ring forms a rotor of the pump, on which acts as a result of the generated pressure, a transverse force, which must be counteracted by a corresponding storage. If this lateral force can not be compensated sufficiently, there will be a displacement of the rotor, which in particular can negatively affect the running properties.

The JP 2012-026294 A shows a fluid pump with a ring gear machine whose inner ring is mounted on a drive shaft and on a housing formed on a stub axle.

The JP 2015-048784 A teaches an electric oil pump with a ring gear machine. A drive shaft of the oil pump is supported at an axial end of the drive shaft in a housing.

From the DE 10 2012 204 191 A1 For example, an electric oil pump is known in which a housing has a bearing portion for supporting a tip end portion of a shaft to supplementally support the shaft.

The EP 1 580 431 A1 , the JP 2015-108306 A and the EP 2 570 672 A2 show gear pumps in which an outer ring gear is supported by a sliding bearing.

The object of the present invention, starting from the prior art, is to minimize the undesirable influence of a transverse force on the rotor of a pump with little effort.

Said object is achieved by a rotor assembly according to the appended claim 1 and by a pump unit according to the attached independent claim 10.

The rotor assembly according to the invention is provided for a pump for conveying a medium. The pump preferably forms a pump unit together with an electric motor. The rotor assembly comprises a rotor which serves by rotation for the direct delivery of the medium and thus forms a pump rotor. The design of the rotor is to be selected according to the applied principle of the pump. If the pump is formed, for example, by a gear pump, then the rotor is a gear or a toothed ring. The medium is preferably a liquid, more preferably an oil.

The rotor has an opening with which it sits non-rotatably on a drive shaft, so that a rotation of the drive shaft leads to a rotation of the rotor. Thus, a torque from the drive shaft to the rotor is transferable. The drive shaft protrudes at least into the opening or preferably through it. The opening forms an axis of rotation of the rotor. The opening constitutes a hub of the rotor and is preferably continuous. The drive shaft forms a component of the rotor assembly.

According to the invention, the rotor in an operating state at an axial position of the drive shaft relative to the drive shaft about any axis perpendicular to the drive shaft tiltable, d. H. tiltable. The said axis of tiltability intersects the drive shaft in said axial position of the drive shaft. The said axis of tiltability has an arbitrary angle of rotation with respect to the drive shaft, so that the tiltability of the rotor is independent of the rotational angle of the drive shaft. The operating condition is a condition in which the rotor is fully mounted on the drive shaft so that the rotor is non-rotatably mounted on the drive shaft and the rotor assembly is usable for its function in the pump.

Since the rotor can be tilted at said axial position about each axis perpendicular to the drive shaft yielding the lateral force, the rotor can follow an occurring lateral force without tilting with respect to the axis of rotation. The lateral force yielding drive shaft is then no longer exactly in the axis of rotation. However, since the rotor due to its tiltability relative to the drive shaft can remain in the axis of rotation, its function in the pump is not limited. In particular, it does not happen that the rotor rotates in the event of tilting with respect to the axis of rotation with increased friction compared to other stationary or rotating components of the pump. Rather, the rotor shifts parallel to its main extension plane.

A particular advantage of the rotor assembly according to the invention is that a storage of the drive shaft and the rotor on both sides of the rotor is not necessary by a low-cost guarantee of said tiltability. It only requires storage on one side of the Rotor, since it is the rotor according to the invention allows to tilt against the lateral force yielding drive shaft.

The tiltability of the rotor relative to the drive shaft is limited, so that the rotor can be tilted up to a maximum tilt angle relative to the drive shaft. The maximum tilt angle is preferably so large that a maximum occurring during operation of the rotor assembly bending of the drive shaft can be compensated so that the rotor does not tilt with respect to the axis of rotation. The maximum tilt angle is preferably at most 5 ° and more preferably at most 1 °. The maximum tilt angle is preferably at least 0.1 ° and more preferably at least 0.5 °.

The opening preferably has a first axial section, which also forms a first axial section of the drive shaft. In this first axial section, a gap extending around the drive shaft is formed in the opening of the rotor between the rotor and the drive shaft, which constitutes a play in the radial direction between the rotor and the drive shaft. The circumferential gap is increasingly formed in the axial direction. Thus, the radially extending size of the gap, i. H. the gap width in the axial direction too. This gap which increases in the axial direction allows the tiltability of the rotor according to the invention relative to the drive shaft, without the play between the rotor and the drive shaft being unnecessarily large.

Said radial direction is related to the axis of rotation; d. H. that the radial direction is perpendicular to the axis of rotation, namely in the direction of the radii, starting from the axis of rotation. Said axial direction is the direction of the axis of rotation.

The first axial section preferably comprises at least half of the axial length of the opening, but may also comprise the entire axial length of the opening.

In preferred embodiments of the rotor assembly according to the invention, the drive shaft has a convex longitudinal section in an axial region carrying the rotor, in particular in the first axial section. The longitudinal section lies in a plane in which the axis of rotation is located. The convexity is formed with respect to the shaft bearing surface in the opening of the rotor and allows the tilting of the rotor relative to the drive shaft.

In preferred embodiments of the rotor arrangement according to the invention, the rotor has a convex longitudinal section in the region of its opening, in particular in the first axial section of its opening. The longitudinal section lies in a plane in which the axis of rotation is located. The convexity is formed with respect to the drive shaft and allows the tilting of the rotor relative to the drive shaft.

The opening preferably further has a second axial section, which also forms a second axial section of the drive shaft. In the second axial section, the opening has a non-circular cross-section, to which the drive shaft has a corresponding cross-section, so that the rotor sits in the second axial section in a form-fitting manner on the drive shaft and torque can be transmitted from the drive shaft to the rotor. The cross section lies in a plane which is perpendicular to the drive shaft or perpendicular to the opening. The non-circular cross section of the opening or the corresponding cross section of the drive shaft is preferably formed by a polygonal or by a single or multiple flat. The polygon is preferably formed by a square. The multiple flat is preferably formed by a two-flat. Between the non-circular cross-section of the opening and the corresponding cross-section of the drive shaft in the radial direction preferably a game is present, which is preferably between 0.05 mm and 0.5 mm.

The drive shaft preferably further comprises an axial motor portion, in which the drive shaft forms a component of an electric motor for driving the pump; in particular a motor shaft of a motor rotor. The axial motor portion is axially spaced from the first axial portion and the second axial portion. The axial motor portion is axially spaced from the rotor of the pump and the opening thereof. In the electric motor, a torque is generated and transmitted to the drive shaft. The torque is transmitted further from the drive shaft to the rotor of the pump.

The first axial section of the drive shaft is preferably arranged axially between the second axial section and the axial motor section. In this case, the second axial section of the drive shaft is preferably formed on one of the two axial ends of the drive shaft. The drive shaft protrudes with its axial end preferably completely into the opening of the rotor. It can protrude with an axial clearance through the opening of the rotor.

In the first axial section, the opening and the drive shaft preferably each have a circular cross section. The cross section lies in a plane which is perpendicular to the drive shaft or perpendicular to the opening.

The first axial section is preferably divided into a first axial section and into a second axial section. The size of the circumferential gap extending in the radial direction, ie the gap width, is constant in the axial direction in the two axial sections, but differs between the two axial sections so that the circumferential gap is increasingly formed in the axial direction. Thus, a step of the gap is formed between the two axial sections. The stepped gap can be given by the fact that the opening in the rotor has different diameters in the two axial sections and / or that the drive shaft has different diameters in the two axial sections.

The circumferential gap preferably has the shape of a hollow cylinder in the two axial sections.

The opening in the rotor preferably has the shape of a cylinder in the first axial section. Insofar as the opening in the two axial sections has different diameters, the opening in the two axial sections preferably has the shape of a cylinder.

The drive shaft preferably has the shape of a cylinder in the first axial section. Inasmuch as the drive shaft in the two axial sections has different diameters, the drive shaft in the two axial sections preferably has the shape of a cylinder.

The second axial section is preferably arranged between the first axial section and the second axial section. As a result, the second axial section is located in a central axial region of the opening. Preferably, the second axial portion is located in an axial center of the opening.

Preferably, the circumferential gap in the second axial section has a smaller size extending in the radial direction, i. H. a smaller gap width, as in the first axial section on. Thus, the play in the radial direction between the drive shaft and the rotor in the second axial portion is smallest. In particular, the play in the radial direction between the drive shaft and the rotor in the second axial section is preferably minimal.

The circumferential gap has in the second axial portion of a radially extending size, d. H. a gap width, which is preferably between one-thousandth and one-hundredth of the diameter of the drive shaft in the second axial section. The circumferential gap has in the second axial portion of a radially extending size, d. H. a gap width which is preferably between 0.01 mm and 0.07 mm, more preferably between 0.03 mm and 0.05 mm.

The circumferential gap has in the first axial portion of a radially extending size, d. H. a gap width which is preferably between one hundredth and one tenth of the diameter of the drive shaft in the first axial section. The circumferential gap has in the second axial portion of a radially extending size, d. H. a gap width, which is preferably between 0.08 mm and 0.3 mm, more preferably between 0.1 mm and 0.2 mm.

The first axial section preferably has an axial length that is between one tenth and five tenths of the axial length of the opening. This axial length is particularly preferably between two tenths and four tenths of the axial length of the opening.

The second axial section preferably has an axial length that is between one tenth and five tenths of the axial length of the opening. This axial length is particularly preferably between two tenths and four tenths of the axial length of the opening. Alternatively, the second axial section preferably has a technically minimum axial length such that it forms a peripheral edge against which the drive shaft and the rotor abut in the radial direction with minimal play. This edge forms the fulcrum for tilting the rotor.

The second axial portion preferably has an axial length that is between one tenth and five tenths of the axial length of the opening. This axial length is particularly preferably between two tenths and four tenths of the axial length of the opening.

The opening further preferably has an axial insertion portion, in which it is widened with respect to the circumferential gap. Preferably, the opening is widened in a cone shape with respect to the circumferential gap. The drive shaft protrudes into the opening of the rotor starting at the introduction section.

In the second axial section, the drive shaft preferably has a smaller extent in the radial direction than in the first axial section. Thus, the drive shaft in the second axial portion preferably has an outer diameter of the non-circular cross-sectional shape which is smaller than that Diameter in the first axial section, in particular smaller than the diameter in the second axial section section.

The drive shaft preferably has a circumferential phase between the first axial section and the second axial section, which is preferably formed at the transition from the greater extent in the radial direction in the first axial section to the smaller extent in the radial direction in the second axial section. This phase is a circumferential slope of the described transition. Due to the phase sufficient tiltability is ensured without the need for a larger gap width in the second axial section.

Between the first axial section and the second axial section, a free space extending in the axial direction is preferably formed between the drive shaft and the rotor. This clearance leads to a play in the axial direction between the drive shaft and the rotor, which prevents a striking lateral abutment when tilting the rotor.

In preferred embodiments of the rotor assembly according to the invention, the drive shaft is formed by a motor shaft of an electric motor. The electric motor is designed to drive the rotor and thus to drive the pump. The motor shaft has the above-mentioned axial motor portion and an axial pump portion, wherein the axial pump portion is seated in the opening of the rotor.

The motor shaft preferably has exactly two axial bearing sections in which it can be stored rotatably; in which it is designed in particular for inclusion in a plain bearing or in a rolling bearing. One of the exactly two bearing sections is arranged at an axial end of the motor shaft opposite the pump section, so that it is located in the axial motor section. The other of the exactly two bearing sections is arranged between the axial motor section and the axial pump section.

In any case, is preferably located at that axial end of the drive shaft, which is located in the axial pump section, no bearing section, d. H. the drive shaft is not formed there for rotary bearing. It is namely a particular advantage of the rotor assembly according to the invention that can be dispensed with a rotary bearing of the drive shaft at this axial end, since the drive shaft can bend slightly under load, without the rotor is tilted relative to the axis of rotation.

The rotor is designed according to the realized operating principle of the pump, which may be any working principle with rotating components. The pump is preferably a gear pump, in particular a ring gear machine, which is also referred to as a gerotor. Thus, the rotor is preferably formed by a gear, in particular by an inner toothed ring.

The rotor, in particular the inner toothed ring, is designed to have an axial play in the pump of preferably less than 0.1 mm, particularly preferably less than 0.02 mm.

The pump is preferably a pump for conveying a working fluid in a motor vehicle; for example, an oil pump.

The pump unit according to the invention serves to convey a medium. The pump unit comprises a pump formed in an axial pump section of the pump unit for direct delivery of a medium. The pump unit further comprises an electric motor formed in an axial motor section of the pump unit for driving the pump. The pump unit comprises the rotor arrangement according to the invention. The drive shaft of the rotor assembly forms a motor shaft of the electric motor and is non-rotatably connected to the rotor arranged in the pump. The electric motor preferably has a motor rotor comprising the motor shaft and a motor stator. The rotor of the pump is preferably formed by an inner ring, wherein the pump preferably further comprises an outer ring, wherein the inner ring and the outer ring form a toothed ring machine.

The pump unit preferably comprises one of the preferred embodiments of the rotor arrangement according to the invention. Moreover, the pump unit preferably also has those features which are specified in connection with the rotor arrangement according to the invention and its preferred embodiments.

The pump unit is preferably an electric oil pump for a motor vehicle.

Further advantages, details and developments of the invention will become apparent from the following description of preferred embodiments of the invention, with reference to the drawing. Show it:

1 a side view of a preferred embodiment of a pump unit according to the invention;

2 : this in 1 shown pump unit in a longitudinal sectional view;

3 a rotor arrangement according to the invention of 1 shown pump unit; and

4 : this in 1 shown pump unit in a perspective detail view.

1 shows a side view of a preferred embodiment of a pump assembly according to the invention, which is designed to convey oil in a motor vehicle. The pump unit includes a pump 01 and an electric motor 02 to drive the pump 01 , The pump 01 includes an inlet 03 and an outlet 04 for the oil to be pumped.

2 shows that in 1 shown pump unit in a longitudinal sectional view. The electric motor 02 includes a motor stator 06 and a motor rotor 07 , The motor rotor 07 includes a motor shaft 08 , which at the same time a drive shaft of the pump 01 forms. The pump 01 includes an inner ring 09 and an outer ring 11 which form a toothed ring machine. The inner ring 09 sits firmly on the drive shaft 08 and forms a rotor of the pump 01 ,

The drive shaft 08 is at exactly two axial positions, each with a roller bearing 12 rotatably mounted; namely on both sides of the motor rotor 07 so that's one of the two rolling bearings 12 axially between the motor motor 07 and the inner ring 09 is arranged. Consequently, the drive shaft 08 only on one of the two sides of the inner ring 09 stored, so one in the pump 01 arranged axial end 13 the drive shaft 08 is not stored.

Using the pump 01 is an acting on the oil to be conveyed pressure between 3 bar and 25 bar generated. Due to the principle of action of the inner ring 09 and the outer ring 11 formed ring gear machine acts on the inner ring 09 a lateral force on the drive shaft 08 from the direction of the inlet 03 , Because the drive shaft 08 at its axial end 13 is not stored, it comes to a bending of the drive shaft 08 in the region of the axial end 13 so that the drive shaft 08 in this area with respect to a rotation axis 14 is tilted. But this tilting does not lead to the fact that the inner ring 09 opposite the axis of rotation 14 is tilted, since according to the invention, the inner ring 09 opposite the drive shaft 08 can be tilted. This tiltability is independent of the rotation angle of the drive shaft 08 given so that the inner ring 09 at any angle of rotation of the drive shaft 08 opposite the drive shaft 08 is tiltable. This tiltability is due to a special design of the drive shaft 08 in her the inner ring 09 supporting axial range allows. This axial region initially comprises a first axial section 16 and a second axial section 17 , The second axial section 17 serves to transmit a torque from the drive shaft 08 on the inner ring 09 what the drive shaft is for 08 in the second axial section 17 as a cross section has a square, which with a radial clearance of a few tenths of a millimeter in the inner ring 09 sitting. One the drive shaft 08 receiving opening 18 in the inner ring 09 points in the second axial section 17 a four-sided cross-section, so that a rotationally fixed connection between the drive shaft 08 and the inner ring 09 is trained.

The first axial section 16 is in a first axial section 19 and in a first axial section 21 divided. Throughout the first axial section 16 have the drive shaft 08 and the opening 18 each have a circular cross section. Throughout the first axial section 16 is between the drive shaft 08 and the inner ring 09 in the opening 18 a circumferential gap 22 (shown in 3 ), so that a play in the radial direction between the drive shaft 08 and the inner ring 09 given is. However, the circumferential gap 22 in the first axial section 19 about 0.15 mm and in the second axial section 21 only about 0.04 mm wide. Consequently, the gap is 22 in the first axial section 19 larger in the radial direction than in the second axial section 21 , The circumferential gap 22 Can also be used as a free cut in the drive shaft 08 to be discribed.

The drive shaft 08 and the one rotor of the pump 01 performing inner ring 09 form a rotor assembly according to the invention, which by the tiltability of the rotor 09 opposite drive shaft 08 regardless of the angle of rotation of the drive shaft 08 is marked.

3 shows the out of the drive shaft 08 and the inner ring representing a rotor 09 formed rotor assembly of in 1 and 2 shown pump unit in detail. In the second axial section 21 is the circumferential gap 22 only about 0.04 mm wide. Consequently, the circumferential gap 22 very small, so the play in the radial direction between the drive shaft 08 and the inner ring 09 in the second axial section 21 is very small. The second axial section 21 forms the fulcrum for the tilting of the inner ring 09 opposite the drive shaft 08 , The second axial section 21 has an axial length a, which is about one third of an axial length b of the opening 18 is.

On the electric motor 02 (shown in 2 ) facing side has the opening 18 a cone-shaped extension 24 in the form of a phase. The drive shaft 08 has at that end of the first axial section 16 which is the second axial section 17 is facing, a phase 26 on, which also contributes to the Verkippbarkeit. Between the first axial section 16 and the second axial section 17 is between the drive shaft 08 and the inner ring 09 a free space extending in the axial direction 27 present, so that between the drive shaft 08 and the inner ring 09 Also a game is given in the axial direction, which also contributes to the Verkippbarkeit.

4 shows that in 1 and 2 shown pump unit in a perspective detail view, in which the pump 01 is shown in an open state. These are in particular those through the inner ring 09 and the outer ring 11 formed ring gear machine and the drive shaft 08 recognizable. The drive shaft 08 points in the second axial section 17 (shown in 3 ) has a square-shaped cross section.

LIST OF REFERENCE NUMBERS

01

pump

02

electric motor

03

inlet

04

outlet

05

06

motor stator

07

motor rotor

08

Motor shaft / drive shaft

09

Inner ring / rotor of the pump

10

11

outer ring

12

roller bearing

13

axial end

14

axis of rotation

15

16

first axial section

17

second axial section

18

opening

19

first axial section

20

21

second axial section

22

circumferential gap

23

24

cone-shaped extension

25

26

phase

27

free space

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2012-026294A [0003]
• JP 2015-048784A [0004]
• DE 102012204191 A1 [0005]
• EP 1580431 A1 [0006]
• JP 2015-108306 A [0006]
• EP 2570672 A2 [0006]

Claims (10)

Rotor arrangement for a pump ( 01 ) comprising a rotor ( 09 ) for conveying a medium having an opening ( 18 ), with which it on a drive shaft ( 08 ), wherein the rotor ( 09 ) rotatably on the drive shaft ( 08 ), characterized in that the rotor ( 09 ) at an axial position of the drive shaft ( 08 ) relative to the drive shaft ( 08 ) about any axis perpendicular to the drive shaft ( 08 ) is tiltable. Rotor arrangement according to claim 1, characterized in that the rotor ( 09 ) in the region of its opening ( 18 ) and / or the drive shaft ( 08 ) in one the rotor ( 09 ) carrying axial region has a convex longitudinal section. Rotor arrangement according to claim 1 or 2, characterized in that the opening ( 18 ) a first axial section ( 16 ), in which between the rotor ( 09 ) and the drive shaft ( 08 ) a circumferential gap ( 22 ) is formed, which has a radially extending gap width, which is increasingly formed in the axial direction. Rotor arrangement according to claim 3, characterized in that the opening ( 18 ) further comprises a second axial section ( 17 ) in which it has a non-circular cross section, to which the drive shaft ( 08 ) has a corresponding cross section, so that the rotor ( 09 ) in the second axial section ( 17 ) of the opening ( 18 ) positively on the drive shaft ( 08 ) sits. Rotor arrangement according to claim 3 or 4, characterized in that the first axial section ( 16 ) in a first axial section ( 19 ) and in a second axial section ( 21 ), where the gap ( 22 ) in the two axial sections ( 19 . 21 ) is always constant in the axial direction, and wherein the gap ( 22 ) in the second axial section ( 21 ) has a smaller gap width than in the first axial section ( 19 ) having. Rotor arrangement according to claim 5, characterized in that the circumferential gap ( 22 ) in the first axial section ( 19 ) a gap width between 0.08 mm and 0.3 mm and in the second axial section ( 21 ) has a gap width between 0.01 mm and 0.07 mm. Rotor arrangement according to one of claims 3 to 6, characterized in that the opening ( 18 ) further comprises an axial insertion section ( 24 ) in which it is conical with respect to the circumferential gap (FIG. 22 ) is extended, wherein the drive shaft ( 08 ) starting at the introductory section ( 24 ) in the opening ( 18 ) of the rotor ( 09 ) protrudes. Rotor arrangement according to one of claims 1 to 7, characterized in that the drive shaft ( 08 ) further comprises an axial motor section, in which the drive shaft ( 08 ) a component of an electric motor ( 02 ) for driving the pump ( 01 ). Rotor arrangement according to one of claims 1 to 8, characterized in that the rotor by an inner ring ( 09 ) of a ring gear machine ( 09 . 11 ) is formed. Pump unit for conveying a medium, comprising a pump formed in an axial pump section ( 01 ), an electric motor formed in an axial motor section (US Pat. 02 ) and a rotor assembly according to one of claims 1 to 9, wherein the drive shaft ( 08 ) a motor shaft of the electric motor ( 02 ) and rotatably with the in the pump ( 01 ) arranged rotor ( 09 ) connected is.

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