EP2754896B1 - Gas pump with pressure relief for reducing start-up torque - Google Patents

Description

The invention relates to a pump for conveying a gas, which is also referred to below as a gas pump. The gas pump is designed as a vacuum pump. In such pumps, the invention aims at a reduction of forces or torques acting on the conveyor on startup of the pump.

Vacuum pumps, as the invention relates, are used in vehicles, for example, to provide negative pressure for a brake booster. The pump can be arranged laterally on the cylinder head of a vehicle engine and driven by a camshaft of the engine, as was customary for a long time. Due to space restrictions and also to reduce the specific size, also in terms of pedestrian protection and costs, the vacuum pump is recently arranged in tandem with a lubricating oil pump, which supplies the vehicle engine with lubricating oil in the oil sump of the lubricating oil system. Here, the lubricating oil pump and the vacuum pump are usually combined in a common housing, and the two pumps have a common shaft in most applications. The drive of these designated as tandem or duo pumps modules is usually done by the crankshaft via a traction drive or spur gears. In particular, when arranged in the oil sump, but in principle also in other arrangements of the vacuum pump, there is the problem that when starting the engine within about the first half turn of the vacuum pump at this time special tough engine oil must be promoted relatively quickly from the delivery chamber of the vacuum pump. This results in high driving torques of the vacuum pump, so that the risk exists that the conveyor, for example, a wing of the vacuum pump is destroyed by overload or otherwise damaged or caused damage in the drive train of the vacuum pump. A similar problem arises when turning back an oil-filled vacuum pump, for example, when an automobile with the engine off when unloading a car carrier rolls backwards from the van and the still rolling vehicle is decelerated by engaging the engine off.

In order to avoid the aforementioned damage to the conveyor of the vacuum pump and its drive, such vacuum pumps are usually equipped with reverse rotary valves. It is also to avoid unacceptably high drive torques of the vacuum pump at Version in vane type usual to provide the pump or the wing, at least in the critical rotational angle ranges of the pump rotor with a sufficiently large radial backlash to Pumpengehäuseinnenkontor. As a result of this measure, part of the oil still present in the delivery chamber when the engine starts can flow past the end face of the wing during the first revolution of the vacuum pump. In order to prevent or complicate a filling of the delivery chamber with oil after stopping the drive motor, these are provided with oil retention valves in particular arranged in the oil sump vacuum pumps. Another countermeasure for the mentioned problem is to provide an inlet or outlet valve of the vacuum pump targeted with a leak and thereby cause a rapid reduction in the delivery chamber after a stop of the vacuum pump vacuum still existing. Solutions in this regard will be in the US 2012/0060683 A disclosed.

However, the measures mentioned have the disadvantage that they are either connected with additional construction costs and thus costs for the vacuum pump or the evacuation and thus the efficiency of the pump can be reduced. Reducing pump efficiencies, under the constraints of equal evacuation performance, is equivalent to increasing the drive power to the vacuum pumps, resulting in an increase in fuel consumption and hence CO ₂ emissions of the vehicles.

The US Pat. No. 3,865,515 discloses a coolant pump having a delivery chamber, a delivery rotor rotatably disposed about a rotation axis in the delivery chamber, and a cylinder surrounding the delivery rotor and the delivery chamber. The cylinder and the delivery rotor are arranged in a housing of the pump. In the housing, an end plate is further arranged, which is pressed by springs against an end face of the cylinder to complete the delivery chamber on the front side. The end plate is axially and tiltably movable in the pump housing, so that at the relevant end face between the cylinder and the end plate can form a relief gap for pressure relief of the delivery chamber. Due to the relief gap, lubricating oil contained in the coolant can escape from the delivery chamber. The lubricating oil is collected in the pump housing and returned to the lubrication points of the coolant pump within the pump housing.

The GB 2 092 673 A discloses a coolant pump having a pump housing, a delivery chamber formed in the pump housing, and a delivery rotor rotatably disposed about a rotation axis in the delivery chamber. In the housing, an end plate is further arranged, which is pressed by springs against an end face of a peripheral wall of the housing to complete the delivery chamber at the end face. The end plate is axially movable in the pump housing, so that between the relevant end face of the peripheral wall of the housing and the end plate, a relief gap for Pressure relief of the delivery chamber can form. Due to the relief gap, liquid coolant and lubricating oil contained in the coolant can escape from the delivery chamber into the housing.

The US 4 497 618 A is directed to a pump unit consisting of a hydraulic pump and a tandem-type vacuum pump. For example, the vacuum pump is intended to supply a brake booster of a motor vehicle with negative pressure. The hydraulic pump is used to supply a transmission of a power steering system of the motor vehicle with hydraulic fluid. The hydraulic fluid also serves to lubricate and seal the vacuum pump.

From the EP 0 031 756 A2 is a vacuum pump according to the preamble of claim 1 is known.

It is an object of the invention to reduce the forces or moments acting on a conveyor of the gas pump when starting up a gas pump in a cost-effective, structurally simple and reliable manner, but advantageously not adversely affect the delivery rate of the pump by the inventive solution.

The invention is based on a gas pump which has a first housing part with a sealing surface and a second housing part likewise with a sealing surface, furthermore a delivery chamber with an inlet and an outlet for a gas and a delivery device movable in the delivery chamber for conveying the gas. The two housing parts alone can form the delivery chamber with one another, in particular completely enclosing the delivery chamber apart from one or more inlets and one or more outlets. In principle, however, it is also possible for the first housing part and the second housing part to enclose the delivery chamber together with one or more further housing parts of the gas pump. The second housing part is a housing cover, which closes off the delivery chamber at one end face. The housing parts are joined together in such a way that they surround the delivery chamber at least partially, preferably completely, over a chamber circumference and abut against each other with said sealing surfaces to form a sealing joint in order to seal the delivery chamber along the chamber periphery over the length of the sealing joint. In the assembled state, the sealing surfaces are pressed against each other.

In order to reduce the forces or moments acting on the conveyor when starting the gas pump, the second housing part is movable relative to the first housing part against a pressing force, with which these two housing parts are pressed against each other in the region of the sealing joint, such that the sealing joint can be widened. Due to the expansion, a relief gap is formed by the liquid in the delivery chamber, such as in particular lubricating liquid, can escape. The pressing force is generated by means of a pressing device which presses the two housing parts with said sealing surfaces against each other. The pressing device is set up such that, when a maximum pressure prevailing in the delivery chamber and acting on the second housing part is reached, the pressing force of the pressure device is reached and exceeded as the chamber pressure increases, so that the widening movement of the second housing part and, associated therewith, the widening of the sealing joint commences. The maximum pressure is determined by the pressing device. The pressing device may be arranged so that this expansion movement abruptly depending on a prevailing in the delivery chamber relative to the outer environment of the housing parts overpressure or abruptly when exceeding a predetermined maximum pressure. Accordingly, the discharge gap thus formed can gradually or abruptly closed again with a reduction in the pressure in the delivery chamber and thus the sealing joint can be restored by the pressing force of the pressing device.

The second housing part may be flat on a lower side which delimits the delivery chamber on the front side and has the second sealing surface. In a further simplification, the second housing part as a whole can be shaped as a plate, preferably as a thin plate. In particular, it may have a wall thickness of at most a few millimeters, preferably from the range of 1 to 6 mm. Advantageously, the second housing part, a metal sheet, preferably steel sheet, and in particular be formed by punching as a stamped part or by another separation method.

The gas pump is designed as a vacuum pump and serves to supply one or more units of a motor vehicle with negative pressure or is provided for such use. One application to which the invention is directed is that of a vacuum pump for supplying a brake booster or other engine of a motor vehicle with negative pressure. The gas can be air, but in principle also another gas.

The gas pump can be designed as a rotary pump. In such embodiments, the conveyor as a whole may be rotatable in the delivery chamber about an axis of rotation or comprise at least one in the delivery chamber about a rotation axis rotatable conveyor member. The conveyor may also comprise a plurality of rotatable conveyor members rotatable about spaced apart axes of rotation. In particular, the gas pump may be a vane pump and the delivery device may comprise one or more delivery rotors, each having a single or multiple vanes.

The pressure prevailing in the pumping chamber in the delivery chamber relative to the environment of the gas pump negative pressure advantageously supports the pressing force. When the gas pump is arranged in a vacuum system, the inlet of the delivery chamber is connected to an aggregate to be supplied with the negative pressure. The outlet of the delivery chamber may be connected to the environment to expel the sucked gas into the environment. Instead, the outlet of the delivery chamber may also be connected to another unit in order to supply it with the gas delivered by the gas pump. In vacuum pumps, there is the danger that, due to a still immediately after a shutdown of the pump in the delivery chamber still prevailing vacuum fluid, in particular the lubrication and sealing of the gas pump serving lubricating fluid, penetrates into the delivery chamber and this penetrated, excess liquid when starting the gas pump by means of Conveyor must be carried away. The pressing device is advantageously designed with regard to the pressure force generated by it for this load case.

Opens the sealing joint, so escapes in the delivery chamber liquid through the discharge gap in the vicinity of the gas pump, from where the liquid can flow, for example, in a reservoir. The relief gap connects the delivery chamber with the environment of the gas pump or a reservoir for the liquid, closes the delivery chamber so to speak with the environment or the reservoir briefly. If the liquid is preferably a lubricating oil for an internal combustion engine, and the engine oil is an internal combustion engine, the relief gap connects the delivery chamber to the lubricant sump or engine oil sump. Due to the connection with the environment or a liquid reservoir into which or the liquid can escape from the delivery chamber, power losses are reduced. The liquid is not further conveyed empty, useless, for example, in circulation of a gas pump designed as a rotary pump.

In preferred embodiments, the pressing device generates a spring force which forms at least part of the pressing force. The pressing device can generate the pressing force as a whole as a spring force. In principle, however, embodiments are also feasible in which the pressing device generates only a part of the pressing force as a spring force and the remaining part in a different manner, for example by means of an electric or hydraulic drive. However, the generation of the pressing force in the form of a spring force allows structurally simple, inexpensive and particularly reliable versions of the pressing device. On the other hand, it should not be ruled out that the pressing device does not generate the pressing force as a spring force, but only in a different manner, such as electrically or hydraulically. However, such embodiments have the disadvantage that the second housing half must be actively moved to widen the sealing joint by means of the pressing device. The spring force of the pressing device acts the Expansion of the sealing joint and thus acts as a restoring force, which causes a closing of the relief gap with decreasing pressure in the delivery chamber, either in combination with an additional force applied by the pressing device or preferably alone.

If the pressing device generates at least part of the pressing force as a spring force, it is advantageous if the pressing device is elastically yielding over a spring travel which is at least as great as a largest gap width of the relief gap. This applies both to embodiments in which the pressing force is generated as preferred exclusively as a spring force, as well as for embodiments in which the pressing device applies a spring force in combination with an additional force to keep the sealing joint closed.

In order to limit the movement of the second housing part in a direction widening the sealing joint and thus the gap width of the relief gap, a stop can be provided, against which the second housing part comes to lie in contact in an end position corresponding to the maximum expansion. Alternatively, the expanding movement of the second housing part may be limited by a spring force counteracting the expansion, increasing during expansion, wherein this spring force limiting the movement may in particular be the pressing force or a part of the pressing force. If the pressing device has one or more spring members for generating said spring force, such a spring member or one or more spring members can not only produce a restoring spring force, but in an additional function also form a fixed stop limiting the movement of the second housing part.

Although the pressing means for generating the pressing force can be fundamentally supported on a supporting device external to the gas pump, embodiments are preferred in which the pressing means only comprise the gas pump or a mounting unit having the gas pump, such as a gas pump and a liquid pump Pump unit, supported. Particularly expedient, the pressing device for generating the pressing force is supported on the one hand on the first housing part and on the other hand on the second housing part, so that the reaction forces occurring when pressing the second housing part are absorbed by these two housing parts.

In embodiments in which the pressing device generates the pressing force to a part or entirely in the form of a spring force, the pressing device comprises at least one spring member which generates the spring force alone or in combination with one or more optional further spring members of the pressing device. The at least one spring member can in particular be a bending stressed spring or a torsionsbeanspruchte spring. As bending stressed springs come, for example disc springs or diaphragm springs or in particular leaf springs and meandering into consideration, while among the torsionsbeanspruchten springs, the helical compression springs are preferred. If the pressing device comprises two, three or even more spring members, what has been said applies to each of the plurality of spring members. In principle, in the case of several spring elements, these can also be designed differently with respect to the stress or with regard to the shape, for example, both a bending-stressed spring and a torsion-stressed spring or leaf springs of different types can be provided. A bending-stressed spring member can be made very easily from a spring plate by a separation process, in particular punching, in combination with at least one forming process and its shape adapted to the geometrical conditions at the installation site.

The one or more spring members has or each have a spring support portion and a spring coupling portion. In Federabstützbereich the respective spring member is supported, and in the spring coupling region, it is coupled to the second housing part. Preferably, it acts in the spring coupling area in the direction of the pressing force on the second housing part. In structurally simple and not least therefore preferred embodiments, it acts in the spring coupling area directly on the second housing part. For example, it can press directly against the second housing part, preferably in the direction of the pressing force. Basically, however, an indirect coupling is feasible. With indirect coupling, the spring member acts via one or more transmission elements on the second housing part, preferably without deflection. The respective spring member may be externally supported in its Federabstützbereich with respect to the gas pump. In particular, however, the respective spring member in its Federabstützbereich on the first housing part, optionally on a third housing part of the gas pump, if one is present, be supported. In a simple and not least therefore preferred embodiment, the respective spring member is supported directly on the first housing part, so that the support does not require a transmission element, but only a corresponding support engagement and preferably simultaneously holding engagement directly from the spring member and the first housing part. In alternative embodiments, the respective spring member can be supported on the first housing part via an additional fastening element, such as a screw element or a press stud element. Such embodiments are appropriate.

The one or more spring members of the pressing device can or may each be manufactured separately from the first housing part and the second housing part and coupled to generate the pressing force or at least part of the pressing force at least with the second housing part and be supported on the first housing part. In alternative embodiments, the Spring member or a plurality of spring members of the pressing device may instead be molded in one piece with the first housing part or preferably the second housing part, for example, formed in a casting or sintering process, or firmly joined to a unit with the first housing part or preferably the second housing part. Particularly useful is the formation of a metal sheet, in particular sheet steel. Thus, the housing part can be obtained with the one or more integrated spring members, for example by punching as sheet metal stamping or by means of another separation process. In such embodiments, the housing part having the spring member integrated in this way or the plurality of spring members integrated in this way may preferably comprise the second housing part, a housing part base structure and either only one or more spring members projecting from this housing part base structure, respectively jointly generated or generate at least a portion of the pressing force. The housing part base structure has the sealing surface of the relevant housing part and can in particular form that part of the relevant housing part which surrounds the delivery chamber. The housing sub-base structure, of which the one spring member protrudes or each protrude more spring members, is advantageously in itself stiff, at least significantly stiffer than the one or more spring members, so that it is not deformed at least in the region of the sealing surface.

If a plurality of integrated spring members are provided, they can protrude in particular in the form of a spring arm along a periphery of the housing part base structure. The one or more integral spring members may or may be straight or curved. Bent spring arms is given preference, as this increases the length of the respective spring arm and the spring force generated by the respective spring arm during expansion of the sealing joint can be adapted more accurately to the pressure conditions in the delivery chamber. In embodiments in which the one or more spring arms are or are straight, the respective spring arm can protrude radially or advantageously outwardly in a radial as well as a tangential direction from the periphery of the housing sub-base structure in a plan view of the housing sub-base structure. In preferred embodiments, the respective spring arm is bent in a plan view of the housing sub-base structure, preferably L- or C-shaped, and has a first spring arm portion projecting outwardly from the periphery of the housing sub-base structure and subsequently having a second spring arm portion thereon, at least substantially parallel to the periphery of the housing sub-base structure. The second spring arm section is preferably longer than the first spring arm section. A Federabstützbereich in which the integrated spring member is supported, preferably attached to the first housing structure, may form an end of the respective spring arm.

The one or more integrated spring members can or can advantageously be shaped so that it or they stand at a standstill of the pump under a spring preload or each stand and thereby the housing sub-base structure and in particular the sealing surface of this housing sub-base structure press against the other housing part, so that the closed sealing joint is obtained. If this is one or the plurality of spring members are formed separately from the housing parts, such a spring member is preferably mounted with bias, so that it is under a spring bias at standstill of the pump.

The integrated spring member may be designed in particular as a bending-stressed spring member. In the case of several integrated spring elements, this advantageously applies to each of these spring elements. In embodiments with an integrated spring element or several integrated spring elements, the respective integrated spring element is firmly connected to the housing part base structure either in the spring coupling region or in the spring support region. The fixed connection solid connection may, as stated, be a joint connection or advantageously obtained by molding the housing part base structure and the respective integrated spring member in one piece, for example by casting. The one or more integrated spring members may or may be firmly joined to the other of the two housing parts, namely either the first or the second housing part, preferably by means of a releasable connection, such as a screw connection. The housing part, which has the one or more integrated spring members, can be shaped overall in the manner of a diaphragm spring or disk spring, wherein this spring totality is advantageously stressed upon expansion of the sealing joint to train and the respective spring member to bending.

If this is one or the plurality of spring members of the pressing device are each formed separately from the first housing part and the second housing part, a respective fastening element, such as a screw element, can be provided for fastening the respective spring element. In simple and not least therefore preferred embodiments, the one or more spring members can each simultaneously also form their fastening element, so that a fastening element in addition to the respective spring member is not required. Thus, the one or more spring members may each be formed in particular as a spring clip, such as spring plate and have one or two Federabstützbereiche, with which or each of which engage around the adjacent housing parts and engage behind one of the housing parts, preferably the first housing part. With the spring coupling region, the respective spring member can press directly or indirectly against the other housing part, preferably the second housing part. The respective spring member may cooperate with the two housing parts, in particular in the manner of closure springs, as they are known, for example, for sealing preserving jars.

In particular, in embodiments in which the one or more spring members of the pressing device is in each case designed as a leaf spring, the respective spring member may have a left and a right Federabstützbereich. The spring coupling portion extends in such embodiments between these Federabstützbereiche and connects them together. The spring coupling region may in particular be convexly shaped with respect to the second housing part and act on the second housing part between the spring support areas in the direction of the pressing force, preferably in direct contact against the second housing part. Preferably, in the area of the spring support portions external to the spring coupling portion, the spring member is offset slightly away from the second housing portion to provide a deflection required for expansion of the second housing portion, i. an elastic yielding to allow the spring member.

In embodiments in which the spring member as described above engages around the first housing part and the second housing part with the one or more spring support areas, the respective spring support area can simultaneously form a guide, along which the second housing part in the expansion movement relative to the first housing part in a Leadership intervention. The respective Federabstützbereich can engage in the guide engagement between lateral guide elements of the second housing part. The guide elements may be side walls of a recess at the peripheral edge of the second housing part or protruding outwardly protruding projections of the second housing part, into or between which acts as a guide Federabstützbereich.

Optionally, the axial clearance of one or more conveyor members of the conveyor is limited by special measures. If the gas pump is designed as a rotary pump, for example with one or more peripheral blades, and accordingly has a delivery rotor, its axial play can be limited by a suitable thrust bearing. If it is a gas pump of the vane type, the single or possibly the more wings may be axially secured to the conveyor rotor. In conventional rotary type gas pumps, the housing cover typically limits axial play. If the second housing part of a rotary-type gas pump according to the invention is a housing cover, the conveying rotor or a wing of a vane-cell type pump can move in the direction of the second housing part during a widening stroke of the second housing part. During the closing movement of the second housing part, this can then press against the conveyor rotor or the wing, which leads to wear. This can be countered by the axial play limitation.

The invention may also be a combination of the gas pump according to the invention with a liquid pump, wherein the liquid pump, the supply of an aggregate with a liquid, such as a working fluid or a liquid lubricant, is used, and wherein this liquid also forms the sealing liquid for the gas pump , The liquid pump may in particular be a lubricant pump for supplying an internal combustion engine or another unit with liquid lubricant. The liquid pump has a delivery chamber and the delivery chamber has an inlet on a low-pressure side of the liquid pump and an outlet for the liquid on a high-pressure side of the liquid pump. The liquid pump further has a drivable conveying device, which can perform a conveying movement in a drive in the delivery chamber, through which the liquid is conveyed from the inlet to the outlet of the delivery chamber. The inlet may be an inlet of the liquid pump upstream of the delivery chamber or an inlet directly into the delivery chamber. The outlet may be an outlet directly of the delivery chamber or an outlet of the fluid pump downstream of the delivery chamber. In the combination of gas and liquid pump can advantageously be provided to connect a formed in the first or the second sealing surface sealing recess of the gas pump with the low pressure side or the high pressure side of the liquid pump and thereby to supply the liquid in such embodiments serves as a sealing liquid for sealing the sealing joint.

The liquid pump has a housing part which forms one or more chamber walls of the delivery chamber of the liquid pump. One of the housing parts of the gas pump can simultaneously also form this housing part of the liquid pump. The housing part in question may in particular comprise the first sealing surface for sealing the delivery chamber of the gas pump.

If the gas pump and the liquid pump are rotary pumps, so that the conveying device of the gas pump and also the conveying device of the liquid pump each have at least one conveying member rotatable about an axis of rotation, it is also advantageous if these conveying members are rotatably mounted about a common axis of rotation. Although the at least two rotatable conveyor members may basically surround each other, more preferably they are coaxially juxtaposed. The at least one rotatable conveying member of the gas pump and the at least one rotatable conveying member of the liquid pump may be rotatable relative to each other, in preferred embodiments, however, they are rotatably connected to each other. They are preferably driven together via a drive wheel. They can be coupled by means of a transmission. In particular, they can be arranged on a common shaft. In such embodiments, these conveying members with the common shaft each torque be joined. It may also be one of the conveying members, either a conveying rotor of the gas pump or a conveying rotor of the liquid pump, formed with the shaft in one piece and only the other conveying rotor with the shaft rotatably connected. In principle, embodiments are also conceivable in which the shaft forms both a conveying rotor of the gas pump and a conveying rotor of the liquid pump in one piece, although in many embodiments this will only be possible with a housing divided in the axial direction.

Although the gas pump may be driven by its own drive motor, for example an electric motor, in preferred embodiments the gas pump is driven by the internal combustion engine and is correspondingly connected to transmit torque to a shaft of the internal combustion engine. The conveyor, such as a rotatable impeller of the gas pump, can be connected torsionally rigid with a shaft of the internal combustion engine, i. be rotatably movable relative to the respective shaft and be rotatably driven according to the rotational speed of the respective shaft, when it is in the gas pump as preferred, a rotary pump. Alternatively, a conveyor wheel of the conveyor may be connected via a transmission having the same or different speed than the speed of the machine shaft, i. be driven in rotation via a reduction or transmission gear. The driving machine shaft may be, for example, a crankshaft or camshaft. The internal combustion engine may in particular be an internal combustion engine.

The gas pump with inventive pressure relief can be realized alone or in a pump unit in which the gas pump is combined with a liquid pump of the type described in a common housing. The gas pump according to the invention can also be combined with a liquid pump, in particular lubricant pump, wherein the two pumps generally common in motor vehicle construction have separate pump housing and are generally arranged at different locations on or close to the internal combustion engine, and wherein the gas pump the liquid circuit of the liquid pump is connected, so it is at the liquid which is to be able to escape from the delivery chamber of the gas pump according to the invention, is the funded by the liquid pump liquid. The invention also relates to an internal combustion engine with a mounted gas pump or pump unit of the type described and also a vehicle, preferably a motor vehicle, with an internal combustion engine with a mounted gas pump or pump assembly of the kind described. The internal combustion engine can in particular form a drive motor of the vehicle. The gas pump or the pump unit may be at least partially immersed in a lubricant reservoir, in particular in embodiments in which it with a liquid pump for Supply of the internal combustion engine is combined with the lubricant in the described pump unit.

Advantageous features are also described in the subclaims and the combinations of the subclaims.

Figur 1

eine Pumpeneinheit mit einer Gaspumpe eines ersten Ausführungsbeispiels in einer isometrischen Sicht auf die Gaspumpe,

Figur 2

die Pumpeneinheit des ersten Ausführungsbeispiels in einer isometrischen Sicht auf eine Flüssigkeitspumpe der Anordnung,

Figur 3

die Pumpeneinheit des ersten Ausführungsbeispiels in einem Längsschnitt,

Figur 4

ein Detail der Figur 3 in vergrößerter Darstellung,

Figur 5

die Pumpeneinheit des ersten Ausführungsbeispiels in einer axialen Sicht auf die Gaspumpe,

Figur 6

eine Pumpeneinheit mit einer Gaspumpe eines zweiten Ausführungsbeispiels in einem Längsschnitt,

Figur 7

ein Detail der Figur 6 in vergrößerter Darstellung,

Figur 8

die Pumpeneinheit des zweiten Ausführungsbeispiels in einer axialen Sicht auf die Gaspumpe,

Figur 9

eine Pumpeneinheit mit einer Gaspumpe eines dritten Ausführungsbeispiels in einem Längsschnitt,

Figur 10

ein Detail der Figur 9 in vergrößerter Darstellung,

Figur 11

die Pumpeneinheit des dritten Ausführungsbeispiels in einer axialen Sicht auf die Gaspumpe,

Figur 12

eine Pumpeneinheit mit einer Gaspumpe eines vierten Ausführungsbeispiels in einem Längsschnitt,

Figur 13

die Pumpeneinheit des vierten Ausführungsbeispiels in einer axialen Sicht auf die Gaspumpe,

Figur 14

ein Detail der Figur 13 in vergrößerter Detaildarstellung,

Figur 15

eine Pumpeneinheit mit einer Gaspumpe eines fünften Ausführungsbeispiels in einem Längsschnitt,

Figur 16

ein Detail der Figur 15 in vergrößerter Darstellung, und

Figur 17

die Pumpeneinheit des fünften Ausführungsbeispiels in einer axialen Sicht auf die Gaspumpe.

The invention will be explained below with reference to exemplary embodiments. The features disclosed in the exemplary embodiments advantageously continue to form the subject-matter of the claims individually and in each combination of features, as well as the embodiments discussed above. Show it:

FIG. 1

a pump unit with a gas pump of a first embodiment in an isometric view of the gas pump,

FIG. 2

the pump unit of the first embodiment in an isometric view of a liquid pump of the arrangement,

FIG. 3

the pump unit of the first embodiment in a longitudinal section,

FIG. 4

a detail of FIG. 3 in an enlarged view,

FIG. 5

the pump unit of the first embodiment in an axial view of the gas pump,

FIG. 6

a pump unit with a gas pump of a second embodiment in a longitudinal section,

FIG. 7

a detail of FIG. 6 in an enlarged view,

FIG. 8

the pump unit of the second embodiment in an axial view of the gas pump,

FIG. 9

a pump unit with a gas pump of a third embodiment in a longitudinal section,

FIG. 10

a detail of FIG. 9 in an enlarged view,

FIG. 11

the pump unit of the third embodiment in an axial view of the gas pump,

FIG. 12

a pump unit with a gas pump of a fourth embodiment in a longitudinal section,

FIG. 13

the pump unit of the fourth embodiment in an axial view of the gas pump,

FIG. 14

a detail of FIG. 13 in enlarged detail,

FIG. 15

a pump unit with a gas pump of a fifth embodiment in a longitudinal section,

FIG. 16

a detail of FIG. 15 in an enlarged view, and

FIG. 17

the pump unit of the fifth embodiment in an axial view of the gas pump.

FIG. 1 shows a pump unit with a gas pump 10 of a first embodiment and a liquid pump 20 in an isometric view of the gas pump 10. The pump unit comprises a common housing 10 for both pumps 10 and 20. Such arrangements of pumps are also referred to as a tandem arrangement. The common housing comprises a housing part 1, the movable components of the pump unit, in particular a conveyor of the gas pump 10 and a conveyor of the liquid pump 20, movably supports, and housing parts 2 and 27, of which the housing part 2 a cover of the gas pump 10 and the housing part 27th forms a lid of the liquid pump 20. The housing part 1 is integrally molded, suitably cast in one piece. In principle, however, it can also be composed of several pieces instead. The housing parts 2 and 27 are each formed in one piece from metal and joined to the housing part 1, for example, as shown in each case by means of a screw connection.

The gas pump 10 and the liquid pump 20 are designed as rotary pumps. The rotary pumps 10 and 20 are arranged coaxially along a common axis of rotation axially one behind the other. The housing part 1 is arranged axially centrally. The housing part 2 is arranged on the one axial end side and the housing part 27 on the other axial end side of the housing part 1.

The conveying device of the gas pump 10 comprises a conveying rotor 11, which is rotatable about the axis of rotation, and a single vane 12, which is coupled with the conveying rotor 11 to transmit torque. The conveyor is correspondingly single-leaf. The conveyor rotor 11 guides the wing 12 radially displaceable. The housing part 1 forms in the region of the gas pump 10 a housing pot, which delimits a delivery chamber 3 on one of the liquid pump 20 axially facing chamber front side and surrounds the chamber periphery. With rotary drive of the conveyor rotor 11 of the wing 12 runs in the delivery chamber 3 and divides the delivery chamber 3 in a feed cell, which increases on a low pressure side of the gas pump 10, and another feed cell, which is reduced on a high pressure side of the gas pump 10. Due to the enlargement of the feed cell, gas is sucked on the low-pressure side through an inlet 4 into the increasing feed cell and then ejected through an outlet 5 when reducing the feed cell on the high-pressure side. The gas pump 10 can be operated in particular as a vacuum or vacuum pump, for example, to supply a brake booster of a vehicle with negative pressure. In such a use, the brake booster or another or further negative pressure to be supplied unit of the vehicle is connected to the inlet 4, and the sucked gas, preferably air, is discharged via the outlet 5 into the environment, for example in a crankcase of an internal combustion engine. At the same time, a lubricant serving to lubricate the conveyor 10 is also ejected through the outlet 5.

The housing part 2 closes the delivery chamber 3 at one end face. FIG. 1 shows the housing part 2 prior to assembly in a position in which the housing part 2 of the facing open end face of the housing part 1 is axially opposite and pressed to close the delivery chamber 3 only axially against the housing part 1 and must be firmly connected to this. In the assembled state, a housing part 2 axially facing sealing surface 6 of the housing part 1 and a housing part 1 axially facing sealing surface 7 of the housing part 2 axially against each other and form a extending around the delivery chamber 3 sealing joint to seal the delivery chamber 3 over its circumference. In the sealing surface 6, a groove-shaped sealing recess 9 is formed completely circumferentially around the delivery chamber 3. In the sealing recess 9, a sealing element 19, for example, a sealing ring is arranged, which is elastically pressed in the assembled state of the housing parts 1 and 2 and thereby ensures the required sealing of the sealing joint. Alternatively, however, the sealing joint between the sealing surfaces 6 and 7 can also be ensured by a sealing liquid located in the sealing recess 9. The sealing recess 9 is filled in such embodiments at least in pump operation with the sealing liquid. An elastic sealing ring or other sealing element is then not required for sealing the sealing joint.

FIG. 2 shows the pump unit of the first embodiment in an isometric view of the liquid pump 20. The liquid pump 20 is like the gas pump 10 of the vane type. In contrast to the gas pump 10, the liquid pump 20 comprises a multi-leaf conveyor with a about the common axis of rotation with the gas pump 10 rotatable conveyor rotor 21 and a plurality of distributed over the circumference of the conveyor rotor 21 arranged wings 22. The liquid pump 20 is adjustable with respect to their specific delivery volume. It comprises an adjusting ring 23, which is mounted pivotably relative to the housing part 1 in order to be able to adjust an eccentricity of the conveyor 21, 22 and thereby the specific delivery volume of the liquid pump 20. A restoring spring 26 exerts on the adjusting ring 23 a restoring force acting in the direction of maximum delivery volume. The adjusting ring 23 is acted upon counteracting this restoring force with the conveyed by the liquid pump 20 hydraulic fluid in the direction of a reduction of the specific delivery volume. The vanes 22 divide a delivery chamber of the liquid pump 20 into delivery cells, which increase in rotational drive of the conveyor 21, 22 and eccentric position of the adjusting ring 23 relative to the axis of rotation on a low pressure side of the delivery chamber, whereby liquid is sucked into the delivery chamber, and on a high pressure side shrink the delivery chamber again so that on the High-pressure side through an outlet 25, the liquid is ejected under increased pressure. In FIG. 2 For example, on the low-pressure side of the liquid pump 20, the entire inlet area is denoted by 24, and on the high-pressure side, the entire outlet area is designated by 25. The inlet region comprises an inlet 24 of the housing part 1, which in FIG. 1 is recognizable, and in the housing part 1 upstream of the feed chamber located inlet portion 24, in which the return spring 26 is arranged by way of example and from which a chamber inlet leads directly into the feed chamber. The outlet region comprises the chamber outlet leading directly from the delivery chamber, furthermore an outlet section 25 formed in the housing part 1 and downstream of this an outlet 25 of the housing part 1.

The liquid pump 20 may in particular be a lubricant pump for supplying an aggregate with a liquid lubricant. In preferred applications, the liquid pump 20 is a lubricant pump for supplying an internal combustion engine, preferably a drive motor of a vehicle, with liquid lubricant.

The pump unit is rotationally driven via a drive wheel 13. If the pump unit is assigned to an internal combustion engine, it can be driven, for example, by a crankshaft of the internal combustion engine via the drive wheel 13. The drive wheel 13 may be part of a traction mechanism or a gear transmission, in principle also be a friction gear. The drive wheel 13 is mechanically coupled to both the conveyor 11, 12 so also with the conveyor 21, 22 and may be rotatably connected in particular with two conveyor rotors 11 and 21.

The pump unit may be partially or wholly submerged in a sump or other type of reservoir of a liquid, in particular a reservoir of liquid conveyed by the liquid pump 20. Thus, the pump unit can be arranged partially or wholly immersed in a lower region, for example on a lower side, of an internal combustion engine, in the lubricant sump of the internal combustion engine. The arrangement in a liquid reservoir, preferably a lubricant reservoir, is advantageous for the sealing of the gas pump. Due to the prevailing in the pumping operation in the delivery chamber 3 negative pressure lubricant may and may be sucked to a certain extent from the environment, the reservoir, via the sealing joint 6, 7 in the sealing recess 9 and from there into the delivery chamber 3. The outside surrounding the gas pump lubricant, which can optionally serve as a sealing liquid at the same time, effectively prevents ambient air in the area surrounded by the lubricant via the sealing joint 6, 7 is sucked, whereby the tightness of the gas pump and thus their efficiency and flow rate can be improved ,

FIG. 3 shows the pump unit of the first embodiment in a longitudinal section.

The FIGS. 3 to 5 show the pump unit of the first embodiment in a longitudinal section ( FIG. 3 ), in a detail ( FIG. 4 ) and in an axial view of the gas pump 10. The housing part 2 is joined to the housing part 1, so that the delivery chamber 3 is tightly closed and the sealing surfaces 6 and 7 together form the sealing joint 8, which surrounds the delivery chamber 3 over the chamber periphery, in that the sealing joint 8 extends around a central longitudinal axis of the delivery chamber 3. The sealing joint 8 is located at an axial end of the delivery chamber 3, in the exemplary embodiment, the sealing surface 6 is an end face at the axially open end of the housing part 2. The housing part 2 is flat over its facing into the delivery chamber 3 end face including the sealing surface 7. In modifications, the sealing joint 8, for example, at an axially recessed position, a shoulder surface, the housing part 1 or, in principle, the housing part 2 may be formed. The formation of the sealing surface 6 at the axial end face of the housing part 1 in combination with the at least on its side facing the housing part 1 side housing part 2, however, facilitates the production and thus reduces costs. For sealing joint 8 is still to be noted that this completely, so over 360 °, rotates.

The housing part 2 is pressed by means of a pressing device 30 against the housing part 1, so that the sealing surfaces 6 and 7 with the formation of the sealing joint 8 sealingly abut each other. The pressing device 30 is designed such that it permits a movement of the housing part 2 relative to the housing part 1 in a direction axially facing away from the housing part 1, when an opening force acting on the housing part 2 in said direction is greater than the pressing force. The opening force can be generated in particular by a pressure prevailing in the delivery chamber 3 overpressure. The pressing device 30 may in particular be designed so that the pressing force exerted by her while ensuring a sufficient seal over the sealing joint 8 at standstill and in the normal operation of the pump, but on startup of the pump in the delivery chamber 3 due to there befindlicher lubricating fluid by the conveying movement the conveying device 11, 12 resulting overpressure causes a widening movement. Because of such an overpressure, the housing part 2 lifts in the region of the sealing joint 8 from the housing part 1 against the restoring pressing force of the pressing device 30, so that the sealing joint 8 expands to a relief gap, pass through the located in the delivery chamber 3 excess lubricating fluid from the delivery chamber 3 and thus can be displaced by the conveyor 11, 12. This reduces the displacement work to be performed and thereby the forces and torques acting on the conveyor 11, 12. As a result, the circumferential inner contour of the delivery chamber 3 and the wings 11 can be better adapted to each other to allow a narrower compared to the prior art gap between the circumferential inner contour and the ends of the wing 11. On a reverse rotary valve to relieve the reverse rotation can be dispensed with. There is no need to take any ventilation measures that would reduce the effective flow rate during normal pump operation.

The pressing device 30 is formed overall as a spring device. It comprises only a single, uniform spring member 31, which is designed and arranged to generate the pressing force as a spring loaded on bending. In the exemplary embodiment, the spring member 31 is a leaf spring. It consists of a left and right Federabstützbereich 32 and a spring coupling portion 33, which extends from the left to the right Federabstützbereich 32. All spring portions 32 and 33 are formed in one piece from spring steel, in the example spring plate. The Federabstützbereiche 32 and the spring coupling portion 33 together form a pair of spring clip, such as a spring steel clip, as it is basically known for closing Einmachgläsern.

The spring member 31 spans the housing part 2. It engages around the spring support areas 32 an outer circumference of the housing part 2 and a radially outwardly projecting shoulder of the housing part 1. In a central region of the housing part 2, the spring member 31 is coupled to the housing part 2 to In this central area to exert the pressure force generated as a spring force on the housing part 2. In a modification, the spring member 31 may comprise a plurality of spring arms, for example, three or four spring arms which protrude outwardly from a central spring member portion in the direction of sealing joint 8 and in the direction of the housing part 2 to the spring force uniformly distributed to the housing part 2 and closer to the sealing joint 8 apply.

The spring member 31 is convexly formed in the spring coupling portion 33 with respect to the housing part 2. In the example, it is a spring plate with a convex profile. The coupling region 33 has the shape of a shallow trough. For example, in modifications, the spring coupling portion 33 may have an approximately circular convex contour or the shape of a flat "V". It bulges in other words between the Federabstützbereichen 32 in the direction of the housing part 2. It presses with a front in the direction of the pressing force against the housing part 2. The spring member 31 is mounted with bias.

The spring member 31 bends in its two Federabstützbereiche 32 from the spring coupling portion 33 each from an enclosed acute angle from. At the free end of the respective Federabstützbereichs 32 it kinks again to form a holding element 34, as best in FIG. 4 is recognizable. The spring member 31 forms in its Federabstützbereichen 32 each have a flat "U" whose short end leg forms the retaining element 34. With the holding element 34 behind the spring member 31 engages the housing part 1, which has a counter-holding element 35 for the purpose of additional security. The holding elements 34 and holding counter-elements 35 can each pairwise form a latching connection. The kinks can be replaced by softer curves. However, highly curved transitions reduce the space required for the pressing device 30, thus allowing a more compact design.

As in FIG. 4 Recognizable, the sealing element 19 may have a diamond profile, so that it can stretch axially over the course of the expansion movement of the housing part 2 over a larger travel, but nevertheless does not prevent the escape of fluid to be displaced by the sealing joint 8. In principle, the sealing element 19 in the profile can also be circular or square, but it is preferably orthogonal to the sealing surfaces 6 and 7 but elongated and may for example also be oval. This applies to all embodiments of a gas pump according to the invention with an elastic sealing element such as the sealing element 19. Further applies to such embodiments that the respective sealing element is preferably arranged with the majority of its measured length in the profile in the sealing recess or secured there by another measure in order to prevent the respective sealing element from being able to be entrained in the case of widened sealing joint 8 by liquid flowing out of the delivery chamber.

If the predetermined by the spring member 31 pressing force is exceeded, the housing part 2 can move away from the restoring pressing force of the spring member 31 in a predetermined either by this pressing force or a mechanical stop end position of the housing part 1. The spring member 31 may itself form such a mechanical stop for the housing part 2, should the housing part 2 not already been held due to the increasing pressing force on lifting, or moved again in the direction of the housing part 1. A mechanical stop, the spring member 31 in particular in the region of the transition of the spring coupling region 33 and the respective Federabstützbereich 32 form.

During the expansion movement, the housing part 2 is guided relative to the housing part 1. This can be done by the pressing device 30, for example, as in the embodiment directly by the spring member 31. The spring member 31 fulfills the guiding function by means of its Federabstützbereiche 32. The guide is particularly in the synopsis of FIGS. 4 and 5 recognizable. The housing parts 1 and 2 form lateral guide elements 36 and 37 for the Federabstützbereiche 32 by each having a shallow recess. The Federabstützbereiche 32 each engage in the associated, in registry with each other located recesses in a guide engagement. The guides 36 and 37 sandwich the spring support portions 32 therebetween. The guide elements 36 of the housing part 1 hold the Spring member 31 in position, and the second housing part 2 is axially guided in the region of the side walls of its guide elements 37 by the spring member 31. The pressing device 30 fulfills in this way the functions of pressing and guiding the housing part 2 and in an advantageous development also a stop for limiting the expansion movement of the housing part second

The FIGS. 6 to 8 show a pump unit with a gas pump 10 of a second embodiment. The pump unit differs from the first embodiment by a modified pressing device 40. Otherwise, it corresponds to the first embodiment. Apart from the differences described below, reference is therefore made to the comments on the first embodiment.

The pressing device 40 has, as in the first embodiment, only a single spring member 41, which is also shaped and arranged as a bending-stressed spring. In contrast to the first embodiment, however, not only provides the spring member 41 for the sufficiently strong, but yielding for the expansion arrangement of the housing part 2. The pressing device 40 has over the spring member 41 addition to a fastening device with fastening elements 44. The spring member 41 corresponds with its coupling region 43 to the spring member 31. However, the left and right outside of the spring coupling region 43 subsequent Federabstützbereiche 42 shortened and no longer surround the housing parts 1 and 2. Rather, the spring member 41 in its Federabstützbereichen 44 by means of fasteners 44th supported on the housing part 1 and also fixed. As regards the spring action or generation and application of the pressing force, the spring member 41 corresponds to the spring member 31st

In FIG. 7 one of the two Federabstützbereiche 42 is shown enlarged. In Federabstützbereich 42, the spring member 41 has a passage for the fastening element 44, which may be formed for example as a screw or pressing bolt. The fastening element 44 first passes through the spring member 41 and then the housing part 2 and projects into a bore of the housing part 1. It can be screwed or pressed in the bore, for example. Furthermore, the fastening element 44 is surrounded in a shaft region between the sealing surface 6 and the Federabstützbereich 42 by a sleeve-shaped guide member 45 which projects into the passage formed in the housing part 2 for the fastening element 44 and in the region of the passage to the housing part 2 has a certain play. The game is dimensioned so that the housing part 2 is guided in an expansion movement of the guide member 45, the guide member 45, however, does not hinder the expansion movement. Instead of an additional guide member 45 and the fastener 44 in the corresponding shaft portion could Guide housing part 2 directly. Tribologically, however, the use of an additional guide member 45 is advantageous.

As well as in FIG. 8 recognizable, is held by the plurality of spaced apart mounting and guiding points, in the embodiment, two fastening and guiding points, the housing part 2 in its mounting position relative to the housing part 1, so that it can perform only the expansion movement and accordingly the closing movement.

The FIGS. 9 to 11 show a pump unit with a gas pump 10 and a liquid pump 20 in a third embodiment, which is derived from the second embodiment and differs from this only by its Andrückeinrichtung 50, so that for explaining the pressing device 50 to the second embodiment and otherwise Reference is made to the first embodiment, in particular also to the explanations of the pressing device 30.

The pressing device 50 has a plurality of separate spring members 51, for example, four spring members 51 were selected. The spring members 51 each have a Federabstützbereich 52 and then a Federkopplungsbereich 53, with which they each press against the housing part 2 in order to press this in the region of its sealing surface 7 against the sealing surface 6 of the housing part 1, in particular in detail of FIG. 10 is recognizable.

The spring members 51 are supported and fixed in their Federabstützbereichen 52 each by means of a fastener 54 on the housing part 1. The fastening elements 54 and guide elements 55 at least substantially correspond to the fastening elements 44 and guide elements 45, so that with regard to the support and fastening of the spring members 51 and the guide of the housing part. 2 Reference is made to the second embodiment.

To more securely ensure that the spring members 51 maintain their desired position during pump operation, the fasteners 54 and the passages projected through them in the spring support portions 52 may be shaped to form an anti-rotation lock for the respective spring member 51 in cooperation. In FIG. 11 This is exemplified for the other spring members 51 only for the lower spring member 51.

The FIGS. 12 to 14 show a pump unit of a fourth embodiment with a modified pressing device 60. A characteristic feature of the fourth A Embodiment is that spring members 61 of the pressing device 60 are an integral part of the housing part 2. It is in this sense to integrated spring members 61st

In the fourth exemplary embodiment, the housing part 2 has a central, inherently rigid housing sub-base structure 2c and, extending beyond a periphery of the housing sub-base structure 2c, the spring members 61 protrude outwards. The spring members 61 are each formed in the form of a spring arm. The spring arms protrude from the housing part base structure 2c initially a short distance to the outside. Each of the short spring arm sections is adjoined by a longer spring arm section which, at an end remote from the short spring section, merges into a spring support region 62 of the respective spring member 61. In this way, each of the spring members 61 has a spring coupling portion 63 projecting freely from the central housing sub-base structure 2c and extending over the major part of its length at least substantially in the circumferential direction. As mentioned, at the ends of the spring coupling portions 63, the spring support portions 62 are arranged. In the Federabstützbereiche 62, the spring members 61 are each immovably fixed relative to the housing part 1. The spring members 61 are in the plan view of FIGS. 13 and 14 at least substantially C-shaped, each having an at least substantially L-shaped spring coupling portion 63.

The housing sub-base structure 2c has, on its inner or lower side facing the housing part 1, the sealing surface 7 in order to form the sealing groove 8 of the fourth exemplary embodiment with the axially facing sealing surface 6. The seal groove 8 extends along the periphery of the housing sub-base structure 2c and in the plan view of FIG FIG. 13 radially within the spring members 61.

The housing sub-base structure 2c and the spring members 61 are molded in one piece, for example, cast from a metallic material, and optionally reworked, or preferably from a metal sheet, in particular steel sheet, stamped or formed by a different separation process. As in the plan view of FIG. 13 recognizable, the housing part 2 forms with the integrated spring members 61 a meander spring whose meandering arms are the spring members 61. The spring members 61 are bending-stressed springs in the form of Mänderarme.n

The housing part base structure 2c may be axially biased by the spring members 61 against the sealing surface 6 of the housing part 1. For this purpose, the spring members 61 may have on their underside a clear distance to the facing end side of the housing part 1 by being there opposite the sealing surface 7 of the housing part 2 (FIG. FIG. 12 ) are a little bit withdrawn. As a result, the housing part 2 can be fastened with pretension on the housing part 1.

In the fourth embodiment, reference was made to an elastic sealing element, such as the sealing element 19 (FIG. FIG. 4 ), waived. Instead, the sealing recess 9 is filled at least during pump operation with a sealing liquid which can be formed in particular by the lubricating liquid for the gas pump 10. The lubricating fluid may be the fluid delivered by the fluid pump 20. Accordingly, in FIG. 12 a supply channel recognizable, through which the sealing recess 9 with the sealing liquid, preferably lubricating fluid, is supplied. Also in the other embodiments, the respective sealing recess 9 may be filled with sealing liquid and be dispensed with an elastic sealing element. On the other hand, even in the fourth embodiment, the liquid seal can be replaced by the arrangement of an elastic sealing element in the sealing recess 9. With regard to the sealing by sealing liquid and the supply of the sealing recess 9 with sealing liquid is based on the German patent application no. 10 2012 222 753.9 referred to in this regard.

Incidentally, the gas pump of the fourth embodiment and also the entire pump unit corresponds to those of the first embodiment.

The FIGS. 15 to 17 show a pump unit of a fifth embodiment. Also in this pump unit, a gas pump 10 and a liquid pump 20 are combined to form a mounting unit. The pump unit corresponds to a further modified pressing device 70 apart from the previous embodiments, so again reference is made to the comments on the first embodiment.

The pressing device 70 includes as in the third embodiment ( Figures 9-11 ) However, it is not as in the other embodiments to bending-stressed spring members, but each a torsionsbeanspruchtes spring member 71, for example, each a helical compression spring. The spring members 71 are fixedly connected to the housing part 1 by means of a respective fastening element 74 extending through them. In each case, at their ends remote from the housing parts 1 and 2, they have a spring support region 72 and the housing part 2 facing a spring coupling region 73, as best shown in FIG FIG. 16 can be seen. They are each biased so that they exert a biasing force and in the sum corresponding to the pressing force on the housing part 2 at standstill of the pump. The spring members 71 are distributed along the sealing joint 8 as in the third embodiment, so that they position the housing part 2 relative to the housing part 1 and fix the opening and closing movement relative to the housing part 2 with the for the tight closure of the delivery chamber. 3 apply required pressing force.

Apart from the differences explained, reference is made to the comments on the other exemplary embodiments.

In the embodiments, an axial securing of the conveying rotor 11 and also of the wing 12 is dispensed with. In a modification, the respective conveying rotor 11 or the respective wing 12 may or may be axially secured in order to prevent the conveying rotor or the wing from moving axially during a widening movement of the housing part 2 and causing a rattling noise.

Reference numerals:

1

housing part

2

housing part

2a

guide element

2 B

retaining element

3

delivery chamber

4

inlet

5

outlet

6

sealing surface

7

sealing surface

8th

sealing joint

9

sealing groove

10

gas pump

11

feed rotor

12

wing

13

drive wheel

14

-

15

feed

16

-

17

-

18

-

19

sealing element

20

liquid pump

21

feed rotor

22

wing

23

collar

24

Inlet, inlet area

25

Outlet, outlet section, outlet section

26

Return spring

27

-

28

-

29

-

30

pressing device

31

spring member

32

Federabstützbereich

33

Spring coupling region

34

retaining element

35

Holding counter-member

36

guide element

37

guide element

40

pressing device

41

spring member

42

Federabstützbereich

43

Spring coupling region

44

fastener

45

guide element

50

pressing device

51

spring member

52

Federabstützbereich

53

Spring coupling region

54

fastener

55

guide element

60

pressing device

61

spring member

62

Federabstützbereich

63

Spring coupling region

64

Befestigungselemet

70

pressing device

71

spring member

72

Federabstützbereich

73

Spring coupling region

74

fastener

75

guide element

Claims (14)

1. A gas pump, being a negative pressure pump for supplying one or more assemblies of a motor vehicle with negative pressure, the gas pump comprising:

   (a) a delivery chamber (3) comprising an inlet (4) and an outlet (5) for a gas;

   (b) a first housing part (1) comprising a first sealing surface (6) which at least partially surrounds the delivery chamber (3);

   (c) a second housing part (2) comprising a second sealing surface (7) which at least partially surrounds the delivery chamber (3), wherein the second housing part (2) together with the first housing part (1) at least partially encloses the delivery chamber (3);

   (d) a delivery device (11, 12), which can be moved within the delivery chamber (3), for delivering the gas;

   (e) and a pressing device (30; 40; 50; 60; 70) which presses one of the housing parts (1, 2) against the other with a pressing force, such that the sealing surfaces (6, 7) abut each other and together form a sealing join (8) which at least partially surrounds the delivery chamber (3), in order to seal off the delivery chamber (3),

   (f) wherein the second housing part (2) can be moved relative to the first housing part (1), against the pressing force, in order to be able to widen the sealing join (8) to form a relieving gap through which fluid situated in the delivery chamber (3) can escape,

   characterised in that

   (g) the second housing part (2) is a housing cover which seals off the delivery chamber (3) on one front face.
2. The gas pump according to the preceding claim, characterised in that the gas pump (10) is connected to a lubricant circuit for lubricating at least one assembly of a motor vehicle, preferably a drive motor and/or gear system of the motor vehicle, and the fluid is the lubricant for lubricating the at least one assembly.
3. The gas pump according to any one of the preceding claims, characterised in that the pressing device (30; 40; 50; 60; 70) is elastically flexible over a spring path which is at least as large as a maximum gap width of the relieving gap.
4. The gas pump according to any one of the preceding claims, characterised in that the pressing device (30; 40; 50; 60; 70) comprises a spring member (31; 41; 51; 61; 71) which generates a spring force which forms at least a part of the pressing force and, in preferred embodiments, the spring member (31; 41; 51; 61; 71) is a flexurally stressed spring (31; 41; 51; 61), such as for example a leaf spring, sinuous spring, disc spring or membrane spring, or a torsionally stressed spring (71) such as for example a helical pressure spring.
5. The gas pump according to the preceding claim, characterised in that the spring member (31; 41; 51; 61; 71) is supported in a spring support region (32; 42; 52; 62; 72) and coupled to the second housing part (2) in a spring coupling region (33; 43; 53; 63; 73) and preferably acts in its spring coupling region (33; 43; 53; 63; 73) on the second housing part (2) in the direction of the pressing force.
6. The gas pump according to the preceding claim, characterised in that the spring member (31; 41) is also supported in an additional spring support region (32; 42) and in that the spring coupling region (33; 43) extends between the spring support regions (32; 42).
7. The gas pump according to any one of the preceding two claims, characterised in that the spring coupling region (33; 43) of the spring member (31; 41) is convex in relation to the second housing part (2) and exhibits a spring bias, which acts on the second housing part (2) in the direction of the pressing force, and preferably presses against the second housing part (2).
8. The gas pump according to any one of the preceding claims and Claim 4, characterised in that the second housing part (2) comprises a housing part base structure (2c) which comprises the second sealing surface (7), and in that the spring member (61) projects from the housing part base structure (2c) and is fixedly connected to the housing part base structure (2c) and preferably formed in one piece together with the housing part base structure (2c).
9. The gas pump according to the preceding claim, characterised in that the pressing device comprises an additional spring member (51; 61; 71) for generating an additional spring force, wherein the sum of the spring forces generated by the spring members (51; 61; 71) forms at least a part of the pressing force, and in that the spring members (51; 61; 71) are supported on mutually spaced points of preferably the first housing structure (1) or are coupled to the second housing structure (2) at mutually spaced points of the second housing structure (2), wherein in the case of the gas pump in accordance with Claim 8, the additional spring member (61) projects from the housing part base structure (2c) and is fixedly connected to the housing part base structure (2c) and preferably formed in one piece together with the housing part base structure (2c).
10. The gas pump according to any one of the preceding two claims, characterised in that the second housing part (2) is fastened on the first housing part (1) by means of the spring member (61) or the additional spring member (61) of Claim 9.
11. The gas pump according to any one of the preceding claims, characterised in that a guide (32; 45; 55; 75) is provided which extends in the direction in which the second housing part (2) can be moved, and the second housing part (2) is guided along the guide (32; 45; 55; 75) when it is moved, wherein the spring member (31) preferably forms the guide (32), preferably with the spring support region (32).
12. The gas pump according to any one of the preceding claims, characterised in that in at least one of the sealing surfaces (6, 7) which form the sealing join (8), a sealing recess (9) extends around the delivery chamber (3) and is filled with a sealing fluid, preferably a lubricant for the gas pump, at least while the gas pump is in operation, in order to seal off the delivery chamber (3) on the outside, such that a seal by means of an additional sealing ring can be omitted.
13. The gas pump according to at least Claim 4 and preferably according to any one of Claims 5 to 12, characterised in that a movement of the second housing part (2) in a direction which widens the sealing join (8) is limited by a spring force, which acts counter to the widening and increases with the widening, or by a fixed abutment (32, 33), wherein the spring member of Claim 4 can form the fixed abutment.
14. The gas pump according to at least one of the preceding claims, characterised in that the pressing device (30; 40; 50; 60; 70) is supported on the first housing part (1) or on an optional additional housing part of the gas pump (10) or on a mounting unit (10, 20) which comprises the gas pump, and acts on the second housing part (2) such that the pressing force which preferably comprises a spring force is completely absorbed by the housing parts (1, 2) or the mounting unit (10, 20).

Images