Mixing chamber for generating pump charging

Abstract

The invention relates to a mixing chamber (2) for generating pump charging in a fluid pump (1), comprising an interior space (20) formed by an inner wall of the mixing chamber (2), a suction inlet (21) opening into the interior space (20) and designed to be connected to a fluid source (4) and to withdraw a fluid therefrom, a charging inlet (22) opening into the interior space (20) and designed to guide a fluid flow into the interior space (20) and thereby generate the pump charging, and an outlet (23) leading from the interior space (20) and designed to guide the fluid introduced into the interior space (20) out of the mixing chamber (2), wherein the charging inlet (22) has at least a first fluid line section (24) designed as a confuser, a second fluid line section (25) designed as a constriction, and a third fluid line section (26) designed as a diffuser.wherein the constriction is arranged between the confuser and the diffuser and has the smallest diameter within the charging inlet (22), wherein the diffuser is formed by a single side surface (27) tilted by an angle (W) relative to a longitudinal axis (L) of the interior space (20).

Description

[0001] The invention relates to a mixing chamber for generating pump charging in a fluid pump. Furthermore, the invention relates to a pump device comprising a fluid pump and such a mixing chamber.

[0002] The concept of pump supercharging in a fluid pump is well known. With pump supercharging, the suction flow leading to a fluid pump is guided through a mixing chamber upstream of the pump. The mixing chamber contains a nozzle through which an additional supercharging flow is added to the suction flow. The supercharging flow introduces kinetic energy into the suction flow, which drives the fluid flow in the mixing chamber toward the fluid pump. This can increase the amount of fluid that can be pumped by the fluid pump. Furthermore, the energy required by the fluid pump to pump the fluid can be reduced.

[0003] Pump supercharging is preferably used for pumps with a purely speed-dependent delivery rate, such as conventional vane pumps. In this case, it can happen that the pump's delivery rate is greater than the actual demand, but on the other hand the pump speed cannot then be easily reduced. This occurs, for example, with mechanically driven vane pumps, particularly hydraulic pumps in vehicle transmissions. Instead of the excess fluid being directed from the pump outlet back into a fluid reservoir, at least a portion of it is used as a boost flow for pump supercharging. The energy required by the pump to deliver the fluid is then reduced by pump supercharging.

[0004] Hydraulic pumps, such as vane pumps, are prone to cavitation if the minimum inlet pressure in the pump inlet falls below the vapor pressure of the pumped medium or the dissolved air. This usually occurs at high pump speeds. Cavitation is the local outgassing of air from the medium or evaporation of the medium in the low-pressure region and the subsequent collapse of these gas bubbles in higher-pressure regions. This effect can lead to component damage and unwanted noise. In transmission technology, hydraulic oil pumps are often linked to the engine speed via a gear ratio. Due to the high oil demand even at low engine speeds, a fixed gear ratio greater than 1 is selected. This improves the oil supply to the gearbox at low engine speeds. However, the fixed gear ratio greater than 1 also leads to high pump speeds at high engine speeds.High pump speeds increase the risk of cavitation within the pump. To improve this behavior, excess oil not used by the consumer is typically returned to the pump.

[0005] From the published patent application DE 10 2007 027 222 A1, a connection arrangement for connecting to an intake side of an oil pump in a housing of a vehicle transmission is known, wherein a separate intake manifold with an integrated intake booster is provided.

[0006] A suction-charged pump for pumping a liquid is known from published patent application DE 10 2011 084 405 A1. This pump comprises a substantially cylindrical mixing chamber into which a suction flow from the pump can be fed. A nozzle opens into the mixing chamber at an acute angle such that the motive flow flowing out of the nozzle forms a combined mixed flow with the suction flow. This mixed flow allows a partial flow at the same pressure to be fed to each of the front suction kidneys and a rear suction kidney of the pump.

[0007] Furthermore, from the published patent application DE 10 2021 211 785 A1, a mixing chamber with a suction inlet, a charging inlet and an outlet is known, wherein the charging inlet opens into the interior of the mixing chamber at an angle along an inner wall, so that a mixed flow with a swirl is generated within the interior.

[0008] The object of the present invention is to improve a mixing chamber for generating pump charging in a fluid pump. In particular, cavitation is to be reduced. This object is achieved by a mixing chamber having the features of independent patent claim 1. Advantageous embodiments are the subject of the dependent claims, the following description, and the figures.

[0009] A mixing chamber according to the invention for generating pump charging in a fluid pump comprises an interior space formed by an inner wall of the mixing chamber, a suction inlet opening into the interior space, which is designed to be connected to a fluid source and to withdraw a fluid therefrom, a charging inlet opening into the interior space, which is designed to guide a fluid flow into the interior space and thereby generate the pump charging, and an outlet leading from the interior space, which is designed to guide the fluid introduced into the interior space out of the mixing chamber, wherein the charging inlet has at least a first fluid line section designed as a confuser, a second fluid line section designed as a constriction, and a third fluid line section designed as a diffuser,wherein the constriction is arranged between the confuser and the diffuser and has the smallest diameter within the charging inlet, wherein the diffuser is formed by a single side surface tilted at an angle relative to a longitudinal axis of the interior.

[0010] In other words, of four side surfaces, only one is tilted at an angle relative to the longitudinal axis of the interior space, such that the cross-sectional area of ​​the diffuser increases with increasing axial distance from the constriction. The diffuser therefore has a flow cross-section that increases toward the interior space. In particular, a side surface is considered to be tilted at an angle relative to the longitudinal axis of the interior space if the angle is at least greater than 2°. Angles of up to 2° may be due to manufacturing reasons and, in particular, may be within a tolerance range.

[0011] The diffuser's irregular shape partially converts the kinetic energy, which was increased in the confuser, i.e., the propulsion nozzle, back into pressure. The increased pressure in the diffuser deflects the propulsion jet in the desired direction and optimally directs it into the suction area. Another portion of the kinetic energy of the propulsion jet is used to increase the pressure upstream of the pump by mixing and balancing the momentum with the suction jet.

[0012] The confuser has a flow cross-section that narrows toward the interior, with the constriction and then the diffuser located downstream of the confuser. The constriction can extend over a section of constant diameter or be formed solely in one plane. The area upstream of the diffuser, i.e. the constriction, can be designed in different ways. For example, depending on the design, the constriction can impart a slight swirl along the inner wall to the intake flow. Depending on the embodiment, this can either assist or weaken the deflection of the propulsion jet. In particular, this area can be used for fine adjustment of the propulsion jet.

[0013] The inventive design of the charging inlet, consisting of a confuser, constriction, and diffuser, allows the cavitation speed to be increased and pump charging to be improved. The cavitation speed is the speed at which the pump begins to cavitate. Because the smallest diameter within the charging inlet is located between the confuser and the diffuser, and the diffuser is formed by a single side surface tilted at an angle to the longitudinal axis of the interior, the geometry of the charging inlet, i.e. the geometry of the charging current supply, is fluidically adapted such that the flow energy in the form of displacement energy, i.e. pressure, does not collide with a pump wall or other components, but optimally supplies the pump's suction kidneys.This improved flow guidance directs the flow past the pump in the desired direction, deflecting it from the radius of the pump cavity toward a second suction kidney of the pump. This reduces kinetic energy losses and thus reduces cavitation. In particular, the pump is designed as a hydraulic vane pump with a purely speed-dependent flow rate.

[0014] The suction inlet is designed to be connected to a fluid source and to draw fluid therefrom. The fluid source is designed in particular as a fluid reservoir, for example as an oil pan. The charging inlet is designed to guide a fluid flow specifically into the interior of the mixing chamber and thereby generate pump charging. The charging inlet thus serves to guide fluid into the interior and thereby support the suction flow present in the interior by introducing kinetic energy. The fluid flow guided into the interior via the charging inlet is referred to as the charging flow. The outlet is designed to guide the fluid introduced into the interior out of the mixing chamber. In particular, the outlet directs the fluid in the direction of the fluid pump, which is to be supported with pump charging.It can be provided that the pump is directly adjacent to the mixing chamber, or that a section of a suction channel is arranged between the pump and the mixing chamber.

[0015] According to a preferred embodiment, the side surface within the diffuser that is tilted relative to the longitudinal axis of the interior space has an angle of at least 10° to at most 45°. Preferably, the side surface within the diffuser that is tilted relative to the longitudinal axis of the interior space has an angle of 20° to 30°. This angular range has proven to be particularly suitable for guiding the drive flow as well as for partially or unilaterally increasing the pressure and thus for deflecting the drive flow. This can further reduce cavitation. For example, the angle of the side surface within the diffuser that is tilted relative to the longitudinal axis of the interior space is 24°. The longitudinal axis of the interior space is perpendicular, i.e. a vertical axis, through the interior of the mixing chamber.

[0016] According to a preferred embodiment, the ratio of the line cross-section at the constriction to the line cross-section at the diffuser outlet is at least 0.5 to at most 0.7. Preferably, the ratio of the line cross-section at the constriction to the line cross-section at the diffuser outlet is at least 0.52 to at most 0.6. This range has proven particularly well-suited for guiding the drive flow, allowing cavitation to be further reduced. For example, the ratio of the smallest cross-section in the constriction to the outlet cross-section at the diffuser is 0.56.

[0017] According to a preferred embodiment, the confuser has a curved wall designed to redirect the fluid from a radial inlet of the confuser and guide it to the constriction formed transversely thereto. In particular, the fluid flows radially into the confuser and is redirected by the curved geometry within the charging port and guided to the constriction, i.e., to the narrowest line cross-section. This section serves to increase the flow velocity.

[0018] According to a preferred embodiment, the charging inlet is formed integrally with the mixing chamber. The mixing chamber and the charging inlet thus consist of a single component. This allows the mixing chamber to be manufactured cost-effectively. The interior of the mixing chamber can also be shaped to be aerodynamically favorable, so that flow losses are low. This is facilitated by the fact that the charging inlet opens into the interior along the inner wall of the mixing chamber. In particular, the suction inlet and the outlet are also components of the one-piece mixing chamber. The mixing chamber is preferably made of plastic and manufactured using the injection molding process. If the mixing chamber is manufactured using the injection molding process, a further side surface within the diffuser can be tilted at an angle relative to the longitudinal axis of the interior in order to optimize demolding during the injection molding process.For example, the further side surface has an angle of at least 0.25° to a maximum of 2° relative to the longitudinal axis of the interior.

[0019] According to a preferred embodiment, the mixing chamber further comprises a first circumferential seal arranged in a region of the suction inlet on an outer circumferential surface of the mixing chamber, a second circumferential seal arranged in a region of the outlet on the outer circumferential surface of the mixing chamber, and a third circumferential seal arranged axially between the first and second circumferential seals on the outer circumferential surface of the mixing chamber. The first circumferential seal is preferably designed as a lip seal and serves to seal the charging inlet, i.e. the charging current line. A lip seal is particularly suitable for preventing a leakage flow from escaping against the suction direction and thus negatively influencing the suction flow. Leakage flows reduce the jet energy and the pump charging. The second and third circumferential seals are preferably designed as O-rings.For example, the third circumferential seal is arranged in the area of ​​the diffuser on the outer peripheral surface of the mixing chamber.

[0020] According to a preferred embodiment, the outer wall of the diffuser, in the region of the side surface tilted at an angle relative to the longitudinal axis of the interior, is designed to redirect the fluid within the interior. This creates a spoiler effect, allowing the fluid flow to be optimally directed to the outlet.

[0021] A pump device according to the invention for a vehicle transmission has a fluid pump for conveying fluid from a pump inlet to a pump outlet and a mixing chamber according to the invention for pump charging, wherein the mixing chamber can be supplied with a fluid flow from the pump outlet to generate the pump charging.

[0022] A vehicle according to the invention comprises at least one pump device according to the invention. The above definitions as well as explanations regarding technical effects, advantages, and advantageous embodiments of the mixing chamber according to the invention also apply mutatis mutandis to the pump device according to the invention and the vehicle according to the invention.

[0023] In particular, the pump device is designed as a transmission pump device of a vehicle, for example, a truck, passenger car, bus, or rail vehicle. A transmission oil is pumped as a fluid by means of the pump device. The fluid reservoir is then, in particular, an oil pan of the transmission.

[0024] Advantageous embodiments of the invention, which are explained below, are illustrated in the drawings, wherein identical or similar elements are provided with the same reference numerals. They show: Fig. 1 is a highly abstracted schematic view of a pump device for a vehicle transmission; Fig. 2 a schematic sectional view of a mixing chamber according to the invention; Fig. 3 a schematic perspective view of the mixing chamber according to the invention; Fig. 4 shows a further schematic sectional view of the mixing chamber according to the invention; Fig. 5 a schematic plan view of the mixing chamber according to the invention; Fig. 6 a further schematic sectional view of the mixing chamber according to the invention; and Fig. 7 a schematic side view of the mixing chamber according to the invention.

[0025] Fig. 1 shows, by way of example, a pump device for generating hydraulic pressure in a vehicle transmission. Such a pump device can also be used for other applications and can also be used to pump other fluids. The pump device has a fluid pump 1 designed as a hydraulic pump and a mixing chamber 2, which is connected upstream of the fluid pump 1 and is provided for generating pump charging. The pump device pumps pressurized hydraulic fluid from a fluid source 4 of the transmission, designed as a reservoir, to a hydraulic consumer 7 of the transmission. The hydraulic consumer can, for example, comprise a hydraulic actuator and / or a lubrication point in the transmission. For example, shifting elements of the transmission can be actuated with the hydraulic fluid pumped by the fluid pump 1 in order to shift gears of the transmission.

[0026] The fluid pump 1 in this case has a non-adjustable delivery volume and is designed, for example, as a vane pump. The delivery volume of the fluid pump 1 depends essentially on the pump speed, i.e. the speed at which the fluid pump 1 is driven. High pump speeds increase the risk of cavitation within the fluid pump 1. The fluid pump 1 draws the hydraulic fluid from the fluid source 4 via a suction line 5. The suction line 5 leads through a filter 6 and through the mixing chamber 2. A valve 3 is connected downstream of the fluid pump 1, via which the hydraulic fluid can be guided, on the one hand, towards the consumer 7 and, on the other hand, via the return line 81 back into the mixing chamber 2 in order to generate the pump charging. The valve 3 is designed, in particular, as a pressure relief valve.The pumped hydraulic fluid is automatically returned to the mixing chamber 2 by valve 3 when the hydraulic pressure downstream of valve 3 exceeds a certain pressure or when the entire delivery rate of the fluid pump 1 is not required. Only the unneeded amount of hydraulic fluid is returned. The consumer 7 is always supplied with a sufficient delivery rate and pressure.

[0027] The concept of pump supercharging is already known per se, which is why it will only be briefly discussed below. The mixing chamber 2 has an interior 20 into which a suction inlet 21 and a supercharging inlet 22 open. The suction inlet 21 is connected to the fluid source 4 and is supplied with hydraulic fluid from there. The supercharging inlet 22 is connected to the return line 81 leading back from the valve 3. The supercharging inlet 22 can thus be supplied, as required, with at least part of the hydraulic fluid pumped by the fluid pump 1. The outlet 23 of the mixing chamber 2 is connected to the inlet of the fluid pump 1. The hydraulic fluid sucked from the fluid source 4 by the fluid pump 1 thus first reaches the interior 20 of the mixing chamber 2 via the inlet 22. This flow is referred to here as the suction flow.In addition, when valve 3 is switched accordingly, pressurized hydraulic fluid is introduced into the interior 20 via the return line 81 and the charging inlet 22. This flow is referred to here as the charging flow. In the interior 20, the suction flow and the charging flow mix with one another, with the charging flow transferring at least part of its kinetic energy to the suction flow. As a result, the suction flow flowing into the mixing chamber is accelerated towards the fluid pump 1. This reduces the energy required by the fluid pump 1 to pump the hydraulic fluid without the pump speed having to be reduced. The efficiency of the fluid pump 1 is improved when suction charging is used. The valve 3 is preferably arranged in a valve plate of a hydraulic control unit of the vehicle transmission. The valve shown in . Fig. The hydraulic fluid lines shown in Figure 1 can be arranged in an associated channel plate and / or the valve plate of the hydraulic control unit. The fluid flow from the mixing chamber 2 to the consumer 7 and from the valve 3 to the mixing chamber 2 is indicated by arrows.

[0028] Fig. 2 to Fig. 7 show different views of the mixing chamber 2 according to the invention, as in the pump device of Fig. 1 is used. In Fig. 2, Fig. 4 and Fig. 6, the mixing chamber 2 is shown in a longitudinal section along the longitudinal axis L. In Fig. 5 the mixing chamber 2 is shown according to a plan view. Fig. 3 shows the mixing chamber according to a perspective view and Fig. 7 shows a side view of the mixing chamber 2.

[0029] The mixing chamber 2 is designed to generate a pump charge at the Fig. 1 and has a substantially tubular interior 20 formed by an inner wall of the mixing chamber 2, a suction inlet 21 opening into the interior 20, which is connected to the fluid source 4 from Fig. 1 is fluid-conductingly connected, a charging inlet 22 opening into the interior 20, which guides a fluid flow from the return line 81 into the interior 20, and an outlet 23 leading from the interior 20, which guides the fluid introduced into the interior 20 from the mixing chamber 2 to the fluid pump 1. The suction inlet 21 and the outlet 23 are arranged at the opposite axial ends of the mixing chamber 2, which runs rectilinearly along the longitudinal axis L. The interior 20 also runs rectilinearly along the longitudinal axis L.

[0030] The outlet 23 and the suction inlet 21 are preferably each designed as a plug-in flange. In this way, the mixing chamber 2 can be plugged into a suction channel of the fluid pump 1 and the return line 81 in the channel plate 8 of a hydraulic control unit, on the one hand, and into a suction channel of a valve plate 9 of a hydraulic control unit, on the other hand. On the outside of the mixing chamber 2, an at least partially circumferential collar can be provided, which forms an axial stop for positioning the mixing chamber 2 in its installed position. The collar can have an axial extent that corresponds to the width of an intermediate plate Z arranged between the channel plate 8 and the valve plate 9. In this way, the collar and thus the mixing chamber 2 can be fixed between the channel plate 8 and the valve plate 9 in an opening of the intermediate plate Z.

[0031] Furthermore, the mixing chamber 2 has a first circumferential seal 11, which is arranged in a region of the suction inlet 21 on an outer peripheral surface of the mixing chamber 2, a second circumferential seal 12, which is arranged in a region of the outlet 23 on the outer peripheral surface of the mixing chamber 2, and a third circumferential seal 13, which is arranged axially between the first and second circumferential seals 11, 12 on the outer peripheral surface of the mixing chamber 2. The first seal 11 is designed as a lip seal and comes into contact with the mixing chamber 2 and the valve plate 9 in a fluid-tight manner. The second and third seals 12, 13 are designed as O-rings. The third seal 13 comes into contact with the mixing chamber 2 and the channel plate 8 in a fluid-tight manner. Fluid flowing into the mixing chamber 2 and fluid flowing out of the mixing chamber 2 is indicated by arrows.

[0032] Fig. Figure 3 shows the mixing chamber 2 according to the invention in perspective from below, i.e., looking into the intake inlet. The mixing chamber 2 is formed as a single piece and can be manufactured, for example, from plastic using an injection molding process. Thus, the intake inlet 21, the charging inlet 22, and the outlet 23 are integral components of the single-piece mixing chamber 2.

[0033] Fig. 4 shows the mixing chamber 2 according to the invention according to a second longitudinal section, wherein the viewing plane according to Fig. 4 compared to the observation level according to Fig. 2 is rotated by 180°. The charging inlet 22 consists of a first fluid line section 24 designed as a confuser, a second fluid line section 25 designed as a constriction and a third fluid line section 26 designed as a diffuser. The constriction is arranged between the confuser and the diffuser and has the smallest diameter within the charging inlet 22. For better understanding, the subdivision of the charging inlet into Fig. 4 is highlighted by horizontal dash-dot lines. Furthermore, Fig. 4 shows that the diffuser has a side surface 27 tilted at an angle relative to the longitudinal axis L of the interior space 20. The confuser has a curved wall 28 that deflects the fluid from a radial inlet of the confuser and leads it to the constriction formed transversely thereto.

[0034] The top view of the mixing chamber 2 according to Fig. Figure 5 illustrates the design of the charging inlet 22, in particular of the diffuser. The charging inlet 22 is formed integrally with the mixing chamber 2. The charging inlet 22 opens into the interior 20 along the inner wall of the mixing chamber 2. As can be seen in particular from Fig. 3 and Fig. As can be seen from Figure 5, the interior 20 of the mixing chamber 2 is aerodynamically shaped, so that flow losses are minimal. The outer wall 29 of the diffuser deflects the fluid flowing in through the suction inlet 21 in the interior 20 in the region of the tilted side surface 27, achieving a spoiler effect.

[0035] Fig. 6 shows the mixing chamber 2 according to the invention according to a third longitudinal section, wherein the viewing plane according to Fig. 6 compared to the observation level according to Fig. 2 or Fig. 4 is rotated by 90°. In Fig. Figure 6 illustrates the design of the diffuser and the constriction particularly well. The side surface 27 within the diffuser, which is tilted relative to the longitudinal axis L of the interior space 20, has an angle W of 24°. Furthermore, the quotient of the line cross-section A1 at the constriction and the line cross-section at the outlet of the diffuser is 0.56. This design of the boost inlet 22 achieves a one-sided pressure increase and optimized fluid guidance, in particular targeted deflection. This reduces cavitation.

[0036] Fig. 7 shows a side view of the mixing chamber 2, in particular from the perspective according to Fig. 6. The charging inlet 22 formed in the side wall of the mixing chamber 2 is between the first and the third seal 11, 13. In the present case, due to the perspective, only the confuser of the charging inlet 22 is visible. Reference symbol 1 fluid pump 2 mixing chamber 20 Interior 21 Suction inlet 22 Turbocharger inlet 23 Outlet 24 first fluid line section 25 second fluid line section 26 third fluid line section 27 tilted side surface 28 curved wall 29 Outer wall of the diffuser 3 valve 4 Fluid source 5 Suction line 6 filters 7 hydraulic consumer 8 channel plate 81 Return line 9 Valve plate 10 intermediate plate 11 first circumferential seal 12 second circumferential seal 13 third circumferential seal A1 Pipe cross-section at the constriction A2 Cable cross-section at the outlet of the diffuser L Longitudinal axis W angle Z intermediate plate QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This 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

[0000] DE 10 2007 027 222 A1

[0005] DE 10 2011 084 405 A1

[0006] DE 10 2021 211 785 A1

[0007]

Claims

[1] Mixing chamber (2) for generating a pump charge in a fluid pump (1), comprising • an interior space (20) formed by an inner wall of the mixing chamber (2), • a suction inlet (21) opening into the interior (20), which is designed to be connected to a fluid source (4) and to withdraw a fluid therefrom, • a charging inlet (22) opening into the interior (20) which is designed to guide a fluid flow into the interior (20) and thereby generate the pump charging, and • an outlet (23) leading from the interior (20) which is designed to guide the fluid introduced into the interior (20) out of the mixing chamber (2), characterized by that the charging inlet (22) is at least • a first fluid line section (24) designed as a confuser, • a second fluid line section (25) designed as a constriction and • a third fluid line section (26) designed as a diffuser, wherein the constriction is arranged between the confuser and the diffuser and has the smallest diameter within the charging inlet (22), wherein the diffuser is formed by a single side surface (27) tilted by an angle (W) with respect to a longitudinal axis (L) of the interior space (20). [2] Mixing chamber (2) according to claim 1, wherein the side surface (27) tilted relative to the longitudinal axis (L) of the interior (20) within the diffuser has an angle (W) of at least 10° to at most 45°. [3] Mixing chamber (2) according to one of the preceding claims, wherein a quotient of the line cross-section (A1) at the constriction and the line cross-section (A2) at the outlet of the diffuser is at least 0.5 to at most 0.

7. [4] Mixing chamber (2) according to one of the preceding claims, wherein the confuser has a curved wall (28) which is designed to deflect the fluid from a radial inlet of the confuser and to guide it to the constriction formed transversely thereto. [5] Mixing chamber (2) according to one of the preceding claims, wherein the charging inlet (22) is formed integrally with the mixing chamber (2). [6] Mixing chamber (2) according to one of the preceding claims, further comprising • a first circumferential seal (11) arranged in a region of the suction inlet (21) on an outer peripheral surface of the mixing chamber (2), • a second circumferential seal (12) arranged in a region of the outlet (23) on the outer peripheral surface of the mixing chamber (2), and • a third circumferential seal (13) arranged axially between the first and second circumferential seals (11, 12) on the outer peripheral surface of the mixing chamber (2). [7] Mixing chamber (2) according to claim 6, wherein the first seal (11) is designed as a lip seal. [8] Mixing chamber (2) according to one of the preceding claims, wherein the outer wall (29) of the diffuser is adapted to deflect the fluid in the interior (20) in the region of the tilted side surface. [9] Pump device for a vehicle transmission, comprising a fluid pump (1) for conveying fluid from a pump inlet to a pump outlet and a mixing chamber (2) for pump charging, wherein the mixing chamber (2) can be supplied with a fluid flow from the pump outlet to generate the pump charging and is designed according to one of the preceding claims. [10] Vehicle with a pump device according to claim 9.

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