EP3081743B1 - Internal gear pump and vehicle with an internal gear pump - Google Patents

Description

The invention relates to an internal gear pump, in particular a trochoid pump, according to claim 1 and a vehicle, in particular a commercial vehicle, with an internal gear pump according to claim 11.

Internal gear pumps are used in a variety of ways, for example as operating fluid pumps in vehicles. When used in this way, operation that is as quiet and quiet as possible is required so that no psychoacoustic noise is transmitted into a driver's cab or passenger cell.

A well-known internal gear or trochoid pump consists of a pump housing with a cylindrical rotor chamber with an external rotor with internal teeth arranged rotatably in the rotor chamber. A rotary-driven inner rotor with external teeth is located in the outer rotor, with the inner and outer teeth interlocking in a trochoidal shape. The inner rotor has one fewer external tooth compared to the internal teeth of the outer rotor. Starting from a reference plane which runs through the axis of rotation and through a first dead center position and through the center of an opposite second dead center position, in the first dead center position an external tooth of the inner rotor lies completely in a tooth engagement area in a tooth space of the outer rotor. In the second, opposite dead center position, an outer tooth of the inner rotor and an inner tooth of the outer rotor lie against each other on the head side in a tooth adjoining area.

During a full revolution of the inner rotor, starting from the reference plane at the first dead center position in the direction of rotation, the pump chambers become larger in a suction chamber formed on the front side of the rotor chamber. Subsequently, after passing through the reference plane at the second dead center position, the pump chambers become smaller again in a pressure chamber also formed on the front side of the rotor chamber, so that the fluid sucked and taken up in the suction chamber in the pump chambers is compressed in the pressure chamber by reducing the size of the pump chambers and pumped out through an outlet opening.

In this internal gear pump or trochoid pump, the tooth or trochoidal shapes of the external teeth and internal teeth are selected so that the tooth surfaces rolling against one another lie closely together in order to achieve high pump efficiencies with the lowest possible fluid mechanical losses. However, this has the disadvantage that volumes of the fluid to be conveyed are trapped in the transition from the pressure chamber to the suction chamber, which can only escape through crushing between tooth flanks of the rotors in the area of the first dead center position. These high-energy flows and the associated fluctuations in the drive torque generate airborne and structure-borne noise emissions, which appear with high harmonics in the respective spectrum. The inevitable generation of squeezing flows leads to a loss of efficiency of the pump due to an increase in the drive torque and, in addition to a significant increase in the sound pressure, also to a development of psychoacoustic parameters that are unpleasant for the human ear. In addition, a pulsed transfer of the delivery volume from the suction chamber into the pressure chamber at the second dead center position generates a pressure surge, which also negatively influences the frequency and tonality spectrum. These identified acoustic disadvantages can limit the area of application of such standard trochoidal pumps in rooms where people coexist, especially when used in vehicles, where noise reduction and acoustic compatibility represent a constant technical challenge.

In order to achieve an acoustic improvement, it is already known ( DE 603 02 110 T2 ), to increase the gap between the tooth tips of the inner rotor and the outer rotor, that is, to make the tooth tips lower than the tooth shapes would require according to the exact trochoid curve. This reduces the generation of squeezing flows of high squeezing intensity, whereby noise pollution can be reduced depending on the individual design of the modified trochoid curve. However, these possible acoustic advantages are offset by the significant disadvantage that, depending on the function, fluid volumes are then circulated between the pressure chamber and the suction chamber, which is associated with high fluid-mechanical losses and a reduction in pump efficiency.

From the US 3,034,448 An internal gear pump is known in which a pressure chamber and a suction chamber are formed on a distributor body. The EP 2 532 894 A1 describes an internal gear pump in which a discharge groove is provided which forms a flow connection between a tooth engagement area and a pressure chamber of the pump.

The object of the invention is to develop a generic internal gear pump so that it can be operated with a high fluid-mechanical efficiency and low noise emissions. A further object of the invention is to propose a vehicle, in particular a commercial vehicle, with such an internal gear pump.

This task is solved with the features of the independent patent claims. Advantageous refinements are the subject of the subclaims related thereto.

According to claim 1, an internal gear pump, in particular a trochoid pump, is proposed for a vehicle, with a pump housing with a rotor chamber in which a toothed ring having internal teeth with internal teeth is accommodated. This toothed ring can be brought into engagement with an internal gear that is mounted eccentrically to the toothed ring and has external teeth with external teeth in such a way that, based on a basic or starting position or based on a dead center position, at least one of the external teeth is in a tooth engagement area between two The internal tooth space located between the internal teeth is located, in particular adapted to the shape and contour, the volumes forming the pump chambers between the internal teeth and the external teeth in a rotor chamber area assigned to a suction space, starting from the tooth engagement area up to a tooth adjoining area, preferably opposite the tooth engagement area, in which at least an external tooth adjoins or rests on the head side of an internal tooth, become larger and become smaller again in a rotor chamber area assigned to a pressure chamber, starting from the tooth adjoining area up to the tooth engagement area. In other words, this means that the volumes forming pump chambers during pump actuation between the internal teeth and the external teeth, starting from the tooth engagement area assigned to a first dead center position in a rotor chamber area assigned to a suction chamber of the pump up to one, preferably opposite the tooth engagement area, and one The tooth adjacent area assigned to the second dead center position becomes larger and then becomes smaller again after passing through the tooth adjacent area in a rotor chamber area assigned to a pressure chamber up to the tooth engagement area. According to the invention, at least one relief channel is now provided, which forms a flow connection between the tooth engagement area and the pressure chamber, so that a fluid or a squeeze flow can flow or flow out from the tooth engagement area to the pressure chamber.

This means that in this area the enclosed volumes that would otherwise form critical squeezing flows are specifically diverted into the pressure chamber through the at least one relief channel, or fluid squeezed in this area can always escape towards the pressure chamber. This discharge into the pressure chamber minimizes crushing losses, so that the generation of noise is also minimized. However, in contrast to the measure in the prior art with an enlarged gap, the squeezing flow diverted into the pressure chamber is still available as a useful volume, so that no fluid-mechanical losses arise due to the targeted discharge of the squeezing quantity into the pressure chamber.

The at least one external tooth lies in the tooth engagement area preferably in the internal tooth space in such a way that it is essentially completely or completely accommodated therein and pump chambers with a zero volume or almost a zero volume are therefore formed there. This means that the at least one external tooth in the tooth engagement area preferably lies completely or essentially gap-free and / or adapted to the shape and contour in the internal tooth space.

Structurally advantageous, the suction chamber and the pressure chamber are spaced apart from the tooth engagement area and/or from the tooth adjacent area and separated from one another in a rotor chamber wall which adjoins, in particular directly adjacent, the front side of the toothed ring and the gear (in particular to the tooth areas of the toothed ring and the gear formed by the toothing). of the pump housing or open there. Particularly in connection with such an embodiment, it is advantageous in terms of production technology if the at least one relief channel is formed in a wall region of the rotor chamber wall of the pump housing that is adjacent to, in particular immediately adjacent to, the tooth engagement region and, starting from there, is formed or opens at a distance therefrom in the rotor chamber wall Pressure room is guided. In terms of manufacturing technology, the at least one relief channel is preferably designed as a groove that is open to the rotor chamber and thus to the toothed ring/gear.

According to a specific advantageous embodiment, with which a particularly good removal of the squeezing flow from the tooth engagement area is possible, the at least one relief channel is designed in such a way that its tooth engagement area side channel end in the tooth engagement area is assigned only to the outer tooth of the internal gear.

Furthermore, a specific embodiment is particularly preferred in which the at least one relief channel is dimensioned in terms of its channel cross section such that at least 60% of a squeezing flow in a tooth engagement area can be diverted out of it into the pressure chamber. This ensures that the largest possible amount of squeezing flow flows away from the tooth engagement area towards the pressure chamber.

The special design of the at least one relief channel provides targeted optimization options for a current pump design. This allows psychoacoustic noise to be minimized, particularly in terms of loudness in the frequency groups Bark 5-15 and in terms of roughness. The at least one relief channel can be designed with regard to its channel cross-section and/or its channel length in such a way that the specific loudness of the pump during operation in the frequency groups Bark 5-15 is reduced in such a way that it is a maximum of 3 sone/Bark and/or as a result in the range of frequency groups Bark 5-15 results in a maximum roughness of 1.2 asper/Bark.

According to the invention, at least one additional channel is provided, which forms a flow connection between the tooth adjacent area and the pressure chamber. This advantageously minimizes the pressure surge of the conveyed fluid at the transition from the suction chamber to the pressure chamber, so that psychoacoustic parameters can also be optimized with this measure without this leading to losses in efficiency.

According to the invention, the at least one additional channel is formed in a wall region of the rotor chamber wall which is adjacent to the tooth adjacent region, in particular immediately adjacent, and is guided from there to the pressure chamber which is also formed and/or opens out in the rotor chamber wall at a distance therefrom, it can preferably be provided that the at least an additional channel is designed as a groove open towards the rotor chamber. This results in an advantageous functional and easy-to-produce embodiment.

The special design of the at least one additional channel also provides targeted optimization options for a current pump design. The at least one additional channel is preferably designed in terms of its channel cross-section and/or its channel length in such a way that the specific loudness of the pump during operation in the frequency groups Bark 3-10 is reduced in such a way that it is a maximum of 4 sone/Bark and/or this results in a maximum roughness of 2 asper/Bark in the range of frequency groups Bark 3-10.

According to a further preferred and structurally simple pump design, it is provided that the suction chamber and the pressure chamber lie on opposite sides of a reference plane defined by the tooth engagement area and the tooth adjacent area (the tooth engagement area and the tooth adjacent area advantageously lying opposite one another) and are each spaced apart from these areas in one of the rotor chambers End wall of the pump housing. Alternatively or additionally, this reference plane can also be set by one or more axes of rotation of the toothed ring or internal gear, at least one of which is designed to be rotatable.

Through a suitable design of the relief channel and/or the additional channel, the specific loudness and roughness can be defined in such a way that, in addition to a significant reduction in the pressure pulsation and reduction in the emitted sound pressure level, there is a significant optimization of the psychoacoustic parameters, which does not cause any loss of efficiency.

According to a particularly preferred embodiment, the internal gear pump is a trochoid pump in which the teeth mesh with one another in a trochoidal shape.

A further preferred embodiment is one in which the internal gear has one fewer external tooth compared to the internal teeth of the toothed ring. Particularly advantageous results were achieved in this context with a trochoid pump in which the gear ring has seven internal teeth and an internal gear has six external teeth.

The toothed ring is, for example, an external rotor rotatably arranged in the rotor chamber. Alternatively, only the internal gear can be designed as a rotationally driven internal rotor. Particularly preferred is an embodiment in which both the toothed ring as an external rotor and the internal gear as an internal rotor are rotationally driven.

The advantages resulting from the claimed vehicle are identical to the advantages mentioned above and are no longer explicitly repeated here.

The invention is further explained using a drawing merely as an example.

Fig. 1

eine Draufsicht auf eine als Trochoidenpumpe ausgebildete Innenzahnradpumpe in Achsrichtung bei abgenommenem Gehäusedeckel, und

Fig. 2

einen Schnitt durch die Trochoidenpumpe nach Fig. 1 entlang der Bezugsebene A-A.

Show it:

Fig. 1

a top view of an internal gear pump designed as a trochoid pump in the axial direction with the housing cover removed, and

Fig. 2

a section through the trochoid pump Fig. 1 along the reference plane AA.

In Fig. 1 is a top view of an internal gear pump designed as a trochoid pump 1 (without housing cover) and in Fig. 2 a sectional view along reference plane 2 (line AA). Fig. 1 shown.

The trochoid pump 1 has a pump housing 3 with a preferably cylindrical rotor chamber 4, which is protected by a chamber cover 5 (see Fig. 2 ) is closed in operating mode. In Fig. 1 The chamber lid 5 is omitted to provide a view of the chamber interior.

In the rotor chamber 4, an external rotor 6 is rotatably mounted with a preferably identical cylindrical circumference, which is designed as a toothed ring with several, here only by way of example seven, inwardly directed internal teeth 7a to 7g. The cylinder axis of the rotor chamber 4 or the axis of rotation for the outer rotor 6 is marked with the reference number 8.

An inner rotor 11 is arranged or mounted eccentrically in the outer rotor 6 and is driven in rotation about a drive axle 10 by means of a drive shaft 9. The inner rotor 11 is here preferably provided with one fewer external teeth and thus, in the example shown here, with six external teeth 12a to 12f. The inner teeth 7a to 7g and the outer teeth 12a to 12f mesh with each other in a trochoidal shape.

The reference plane 2 passes through the middle of a first (upper) dead center position 13, through the two axes 8 and 10, which are eccentrically offset from one another, and through a second, essentially opposite and lower dead center position 14. At the first dead center position 13 there is an external tooth in a tooth engagement area 13a 12a in an internal tooth space (here between the internal teeth 7a and 7g) essentially completely or completely, that is, essentially gap-free or adapted to the shape and contour. At the second dead center position 14, on the other hand, an external tooth 12d lies in a tooth adjacent region 14a on the head side of the internal tooth 7d or borders there.

When rotating counterclockwise (arrow 15), starting from the reference plane 2 and the first dead center position 13 in the left rotor chamber area, the volumes between the inner teeth and outer teeth as pump chambers 16 increase until the second dead center position 14 is reached. This is due to the increasing Pump chambers 16 suck in fluid to be pumped from a suction chamber 17. The suction chamber 17 is shown here only in dashed lines and is formed in a rotor chamber wall 4a of the rotor chamber 4, at the end adjacent to the tooth areas of the inner rotor 11 and outer rotor 6 (a fluid connection line as an inlet is not shown for reasons of clarity).

In the further course of a revolution of the inner rotor 11, in the rotor chamber area to the right of the reference plane 2 and starting from the second dead center position 14, the pump chambers 16 are reduced in size during a movement towards the first dead center position 13, whereby the fluid taken up in the suction chamber 17 from the pump chambers 16 into a pressure chamber 18 is pressed and derived from this with a pump line (not shown for reasons of clarity). The pressure chamber 18 is also shown here schematically in dashed lines and (like the suction chamber 17) is formed on the front side adjacent to the outer rotor 6 and inner rotor 11 in a rotor chamber wall 4a of the rotor chamber 4. The suction chamber 17 and pressure chamber 18 can, as in Fig. 1 shown, be formed in or on the same rotor chamber wall 4a or alternatively also be formed on different rotor chamber walls 4a, for example, as in Fig. 2 shown, be arranged on opposite rotor chamber walls 4a.

How further from the Fig. 1 As can be seen, both the suction chamber 17 and the pressure chamber 18 have a defined distance from the tooth engagement region 13a and from the tooth adjacent region 14a, so that the rotor chamber walls 4a essentially directly adjoin there. This can lead to the formation of the already mentioned squeezing flows in the tooth engagement area 13a or the generation of pressure surges in the tooth adjacent area 14a.

In order to avoid this and thus reduce noise, in the illustrated embodiment of a trochoid pump 1 there is a groove-like relief channel 19 in a wall region of the rotor chamber wall 4a that is essentially immediately adjacent to the tooth engagement region 13a and in a wall region of the rotor chamber wall 4a that is essentially immediately adjacent to the tooth adjacent region 14a a groove-like additional channel 20 is formed, in other words in or on a substantially direct on the end face of the outer rotor 6 and inner rotor 11 adjacent area of the rotor chamber wall 4a of the rotor chamber 4 is formed, and starting from there in the rotor chamber wall 4a to the pressure chamber 18 which also opens or is formed in the rotor chamber wall 4a at a distance therefrom.

Both the relief channel 19 and the additional channel 20 can be designed as a groove open towards the rotor chamber 4, but if necessary also can be designed as a channel running inside the rotor chamber wall 4a.

In the exemplary embodiment shown, the relief channel 19 runs as a flow channel into the pressure chamber 18, starting from the reference plane 2 and thus starting from the middle of the tooth engagement area 13a. This avoids squeezing flows in the tooth engagement area 13a and leads them into the pressure chamber 18, thereby advantageously reducing psychoacoustic noise in particular.

The additional channel 20 extends from the center of the tooth adjacent area 14a as a flow channel also in the pressure chamber 18. This reduces pulse-like pressure surges at this point at the transition from the suction chamber 17 to the pressure chamber 18, whereby a further reduction in noise is achieved.

Reference symbol list

1

Trochoid pump

2

reference plane

3

Housing

4

Rotor chamber

4a

Rotor chamber wall

5

Chamber lid

6

external rotor

7a - 7g

Internal teeth

8th

Outer rotor axis

9

drive shaft

10

Drive matter

11

inner rotor

12a - 12f

external teeth

13

first dead center position

13a

Tooth engagement area

14

second dead center position

14a

Tooth adjacent area

15

Rotary arrow

16

pump chamber

17

Suction room

18

Pressure room

19

relief channel

20

Additional channel

Claims (11)

1. Internal gear pump, in particular a trochoidal pump, for a vehicle, having a pump housing (3) with a rotor chamber (4), in which an annular gear (6) having an internal gearing with internal teeth (7a-7g) is accommodated, which can be brought into meshing engagement with a gear wheel (11), eccentrically supported in relation to the annular gear (6) and having an external gearing with external teeth (12a-12f), in such a way that at a meshing area (13a) at least one of the external teeth (12a) lies in an internal tooth space situated between two internal teeth (7a; 7g), the volumes between the internal teeth (7a-7g) and the external teeth (12a-12f) forming pump chambers (16) becoming larger in a rotor chamber area, assigned to an inlet port (17) and extending from the meshing area (13a) to a tooth abutment area (14a), in which at least one external tooth (12d) lies or bears contiguously on the crown of an internal tooth (7d), and becoming smaller again in a rotor chamber area assigned to an outlet port (18) and extending from the tooth abutment area (14a) to the meshing area (13a), at least one relief duct (19) being provided, which forms a flow connection between the meshing area (13a) and the outlet port (18),
   characterized in that
   at least one auxiliary duct (20) is provided, which forms a flow connection between the tooth abutment area (14a) and the outlet port (18), the at least one auxiliary duct (20) being formed in a wall area of the rotor chamber wall (4a) contiguous with the tooth abutment area (14a) and is led from there to the outlet port (18) likewise formed and/or opening out in the rotor chamber wall (4a) at a distance therefrom.
2. Internal gear pump according to Claim 1, characterized in that the inlet port (17) and the outlet port (18) are formed and/or open out at a distance from the meshing area (13a) and/or the tooth abutment area (14a) and separately from one another in a rotor chamber wall (4a) of the rotor chamber (4) contiguous, in particular directly contiguous, at the end face with the annular gear (6) and the gear wheel (11).
3. Internal gear pump according to Claim 2, characterized in that the at least one relief duct (19) is formed in a wall area of the rotor chamber wall (4a) contiguous, in particular directly contiguous, with the meshing area (13a) and is led from there to the outlet port (18) likewise formed and/or opening out in the rotor chamber wall (4a) at a distance therefrom.
4. Internal gear pump according to Claim 2 or 3, characterized in that the at least one relief duct (19) is formed as a groove open towards the rotor chamber (4).
5. Internal gear pump according to Claim 3 or 4, characterized in that the at least one relief duct (19) is formed in such a way that its meshing area-side duct end in the meshing area (13a) is assigned solely to the external tooth (12a) of the inner gear wheel (11).
6. Internal gear pump according to one of the preceding claims, characterized in that the duct cross section of the at least one relief duct (19) is dimensioned so that at least 60% of a squeeze flow can be drained off from the meshing area (13a) into the outlet port (18).
7. Internal gear pump according to one of the preceding claims, characterized in that the at least one auxiliary duct (20) is formed as a groove open towards the rotor chamber (4).
8. Internal gear pump according to one of the preceding claims, characterized in that the inlet port (17) and the outlet port (18) lie on opposite sides of a reference plane (2) defined by the meshing area (13a) and the tooth abutment area (14a) and in each case open out in a rotor chamber wall (4a) of the pump housing (3) assigned to the rotor chamber (4) at a distance from these areas (13a, 14a).
9. Internal gear pump according to one of the preceding claims, characterized in that the annular gear (6) is an outer rotor rotatably arranged in the rotor chamber (4) and/or the inner gear wheel (11) is an inner rotor driven to rotate in the outer rotor.
10. Internal gear pump according to one of the preceding claims, characterized in that the gear pump (1) is a trochoidal pump in which the teeth intermesh with one another with a trochoidal shape and/or the gear wheel (11) has one external tooth (12) fewer compared to the internal teeth (7) of the annular gear (6).
11. Vehicle, in particular a commercial vehicle, having a gear pump (1) according to one of the preceding claims.

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