CN115803528A - Vacuum pump for motor vehicle - Google Patents

Abstract

The invention relates to a motor vehicle vacuum pump (10), comprising - a pump unit (26) having a rotatable pump rotor (28), the pump rotor being arranged for the suction of fluid from the pump unit (26) during pump operation side (30) is pumped to the discharge side (32), - a pump casing (14) having a casing discharge port (24) fluidly connected to the discharge side (32) of the pump unit (26), and - a separate deflection element (44) connected to the pump housing (14) and defining a deflection channel (48) fluidly connected to the housing outlet (24) and configured for pump operation The flow of fluid expelled from the housing outlet (24) is deflected in the meantime. A separate deflection element ( 44 ) enables the spatial orientation of the outlet opening on the atmosphere side to be easily adapted to different installation orientations, so that liquid accumulation in the outlet flow path is reliably prevented. This provides a durable and versatile automotive vacuum pump (10).

Description

Motor Vehicle Vacuum Pumps

The invention relates to a motor vehicle vacuum pump, in particular to an electric rotary vane vacuum pump which provides vacuum for a motor vehicle brake booster.

Motor vehicle vacuum pumps are generally used in motor vehicles to supply a vacuum to a brake booster of a motor vehicle brake system, in particular to supply a vacuum to a vacuum chamber of the brake booster. The automotive vacuum pump may be the sole vacuum source for the brake booster, or it may be used in combination with other vacuum sources, such as the intake system of an internal combustion engine.

A brake booster uses the pressure difference between its vacuum chamber pressure and the surrounding atmospheric pressure to boost the mechanical braking force generated by depressing the vehicle's brake pedal, which mechanically actuates the vehicle's braking system. Therefore, providing a sufficient vacuum for the brake booster vacuum chamber is crucial to ensure reliable operation of the brake booster and thus a reliable and convenient operation of the motor vehicle braking system.

Document WO 2019/034256 A1 discloses, for example, a motor vehicle vacuum pump with a pump unit having a rotatable pump rotor, wherein the pump rotor is provided for pumping fluid from the suction side of the pump unit to the discharge during pump operation. side. The motor vehicle vacuum pump also includes a pump housing with a housing outlet, wherein the housing outlet is fluidically connected to the outlet side of the pump unit. If the motor vehicle vacuum pump is switched off after the pump has been in operation, ambient air is sucked into the pump housing via the housing outlet opening due to the pressure difference between the at least partially evacuated pump housing and the ambient atmosphere. The disclosed automotive vacuum pump has a special discharge channel with a sharply enlarged cross-section towards the discharge port to reduce the inflow velocity of ambient air at the discharge port during pump exhaust, thereby reducing moisture and particle ingress pump housing. This provides a relatively durable automotive vacuum pump.

However, the motor vehicle vacuum pump of document WO 2019/034256 A1 must be installed in the motor vehicle in a prescribed orientation with the outlet opening facing downwards in order to prevent liquids, such as condensation water, from accumulating in the outlet channel. This defined installation orientation clearly limits the installation possibilities and thus the application possibilities of the disclosed motor vehicle vacuum pump.

The problem underlying the invention is therefore to provide a durable and versatile vacuum pump for motor vehicles.

The technical problem is solved by a motor vehicle vacuum pump having the features of claim 1 .

The motor vehicle vacuum pump according to the invention has a pump unit with a rotatable pump rotor. The pump rotor is arranged in the pump chamber and is provided for pumping fluid from the suction side of the pump unit to the discharge side of the pump unit when the pump rotor is driven during pump operation. The pump chamber is preferably substantially cylindrical and the pump rotor preferably comprises a rotor body which is arranged eccentrically in the pump chamber and comprises a plurality of radially slidable rotor blades. During pump operation, the rotor blades are in radial contact with the pump chamber side walls and define a plurality of rotating, fluidly separated pump chamber compartments that deliver fluid from the suction side of the pump unit to the discharge side of the pump unit. The pump unit is designed such that the volume of the pump chamber changes during its movement from the suction side to the discharge side, so that the delivered fluid is compressed.

The motor vehicle vacuum pump according to the invention is also provided with a pump housing which includes a housing outlet. The pump housing is typically made up of a number of housing sections defining a number of housing chambers. The pump housing typically defines at least a pump chamber and a motor chamber. The case discharge is fluidly connected to the discharge side of the pump unit such that fluid is discharged to the ambient atmosphere via the case discharge during operation of the pump. The housing discharge may be a simple opening in the housing side wall, or may be defined by a housing discharge tube/nozzle protruding from the housing side wall. The housing outlet generally has an essentially circular opening cross section.

According to the invention, the motor vehicle vacuum pump comprises a separate deflection element connected to the pump housing. The deflection element defines a deflection channel that is fluidly connected to the housing outlet such that fluid is discharged to the ambient atmosphere via the deflection channel during operation of the pump. The deflection channel preferably discharges directly into the surrounding atmosphere, so that the deflection channel defines the last section of the discharge flow path. The deflection channel is configured to deflect the fluid flow discharged from the casing discharge port during pump operation, ie the deflection channel is designed to change the flow direction of the fluid when the fluid passes through the deflection channel. The outlet channel can be curved or angled, for example. The discharge channel can also be designed straight, but inclined relative to the discharge direction of the housing discharge opening. In any case, the deflection channel is designed such that the flow direction of the fluid flowing through the outlet channel is deflected relative to the flow direction of the fluid at the housing outlet.

The separate deflection element according to the invention can be easily adapted to different installation orientations of the motor vehicle vacuum pump. In particular, the deflection element can be easily designed such that, if a motor vehicle vacuum pump is installed, the end of the deflection channel on the ambient atmosphere side is oriented downwards. The downwardly directed deflection channel allows liquid, such as condensate, to escape from the deflection channel and also minimizes the amount of moisture and particles entering the pump housing during pump venting. The separate deflection element enables an easy adaptation of the motor vehicle vacuum pump to different installation orientations and thus to different installation positions without the need to redesign the (complete) pump housing. Thus, the independent deflection element according to the invention provides a durable and versatile motor vehicle vacuum pump.

In a preferred embodiment of the invention, the deflection element and/or the pump housing are designed such that the deflection element can be connected to the pump housing in different orientations relative to the pump housing. This enables different spatial orientations of the deflection elements, in particular different spatial orientations of the ambient-atmosphere-side ends of the deflection channels with identical deflection elements. This enables the motor vehicle vacuum pump to be adapted to different installation positions by simply connecting the deflection element to the pump housing with different spatial orientations, and thus provides a multipurpose motor vehicle vacuum pump.

Preferably, the deflection element is provided with a fixed receptacle and the pump housing is provided with a protruding housing discharge tube which defines a housing discharge opening and is inserted into the fixed receptacle, In order to fasten the deflection element at the pump housing. This enables a simple connection of the deflection element to the pump housing by “swiping” the housing outlet tube into the fixed receptacle of the deflection element. The fastening receptacle and/or the housing outlet are preferably designed such that the deflection element can be connected to the pump housing in different spatial orientations. More preferably, the fastening receptacle is provided with a substantially cylindrical opening and the housing outlet is provided with a corresponding substantially cylindrical outer surface, so that the deflection element can be rotated in different rotational orientations relative to the housing outlet. connect. The inner surface of the fastening receptacle and the outer surface of the housing outlet are generally designed to provide a frictional or positive fit in the circumferential direction in order to prevent unintentional rotation of the deflection element on the housing outlet. This provides a versatile automotive vacuum pump.

In a preferred embodiment of the present invention, the outlet channel section of the deflection channel away from the housing outlet is designed to be angled relative to the inlet channel section of the deflection channel close to the housing outlet, and the outlet The channel section is preferably substantially perpendicular to said inlet channel section. The inlet channel segment is usually centered with the housing discharge. The angular deflection makes it possible to simply change the spatial orientation of the end of the deflecting channel on the ambient atmosphere side and thus the orientation of the deflecting element by rotating the deflecting element about the axis of extension of the inlet channel section and thus by rotating the deflecting element about the center of the outlet opening. discharge direction. This enables the motor vehicle vacuum pump to be easily adapted to different installation positions by rotation of the deflection element, thus providing a versatile motor vehicle vacuum pump.

Preferably, the inlet channel section of the deflection channel close to the housing outlet opening is provided with a smaller flow cross-sectional area than the flow cross-sectional area of the outlet channel section of the deflection channel remote from the housing outlet opening. The larger flow cross-sectional area of the outlet channel section reduces the flow velocity at the outlet of the deflecting channel on the ambient atmosphere side relative to the flow rate at the inlet of the deflecting channel on the housing outlet side. This reduces the inflow velocity of ambient air at the outlet opening of the deflection channel during vacuum pump venting and thus significantly reduces the ingress of moisture and particles into the pump housing.

More preferably, the deflection channel comprises an intermediate channel segment fluidly connecting the outlet channel segment with the inlet channel segment, wherein the intermediate channel segment is provided with a flow cross-sectional area smaller than the flow of the outlet channel segment. The cross-sectional area is preferably smaller than or equal to the flow cross-sectional area of the inlet channel segment. This further reduces moisture and particles entering the pump housing.

In a preferred embodiment of the invention, the deflection element is produced from an elastic plastic, preferably rubber. The elastic deflection element enables a simple press-fit connection of the deflection element to the pump housing. This enables a secure connection of the deflection element without requiring any additional fastening means.

Embodiments of the invention are described with reference to the accompanying drawings, in which:

FIG. 1 shows a motor vehicle vacuum pump according to the invention, wherein the deflection element is arranged in a first direction,

Figure 2 shows an enlarged view of the pump section of the automotive vacuum pump of Figure 1, and

FIG. 3 shows the motor vehicle vacuum pump of FIG. 1 , wherein the deflection element is arranged in a second, opposite direction.

FIG. 1 shows a motor vehicle vacuum pump 10 , which is used in a motor vehicle brake system to provide a vacuum for a vacuum chamber of a motor vehicle brake booster 12 .

The motor vehicle vacuum pump 10 comprises a substantially cylindrical pump housing 14 with a pot-shaped housing body 16 and a housing cover 18 connected to the housing body 16 . The pump housing 14 is provided with a housing discharge pipe 20 which protrudes radially from a housing side wall 22 of the housing body 16 . The housing outlet 20 is designed cylindrically and is arranged in one piece with the housing side wall 22 . The housing outlet 20 delimits a circular housing outlet 24 at its end remote from the housing side wall.

The motor vehicle vacuum pump 10 includes a pump unit 26 which is arranged in the pump housing 14 . The pump unit 26 includes a rotatable pump rotor 28 which is provided for pumping fluid, in particular gas, from a suction side 30 of the pump unit 26 to a discharge side 32 of the pump unit 26 during pump operation. In the illustrated embodiment, the automotive vacuum pump 10 is a rotary vane pump, wherein the pump rotor 28 includes a plurality of rotor blades designed to slide radially and rotate within a substantially cylindrical pump chamber.

The suction side 30 of the pump unit 26 is fluidly connected via a check valve 34 to the motor vehicle brake booster 12 , in particular to a vacuum chamber of the motor vehicle brake booster 12 . Check valve 34 allows fluid to flow from vehicle brake booster 12 to pump unit 26 during pump operation and prevents fluid flow from pump unit 26 to vehicle brake booster 12 if vehicle vacuum pump 10 is off.

The outlet side 32 of the pump unit 26 is fluidically connected to the housing outlet 24 of the housing outlet 20 via an outlet channel 36 inside the housing.

The motor vehicle vacuum pump 10 also includes an electric motor 38 arranged in the pump housing 14 . The electric motor 38 is provided to drive the pump rotor 28 via a rotor shaft 40 which is connected in rotation with the pump rotor 28 . In the depicted embodiment, the electric motor 38 is electronically commutated and configured to operate at a variable motor speed.

The motor vehicle vacuum pump 10 also includes a pump control unit 42 which is provided for controlling the electric motor 38 . In the depicted embodiment, the pump control unit 42 is arranged to provide closed loop control of the variable motor speed of the electric motor 38 .

The motor vehicle vacuum pump 10 also includes a separate substantially L-shaped deflection element 44 connected to the pump housing 14 . In the illustrated exemplary embodiment, the deflection element 44 is produced from rubber and is provided with a substantially cylindrical fastening receptacle 46 . The deflection element 44 is fastened to the pump housing 14 by means of a press-fit connection, which is formed by pressing the housing discharge line 20 of the pump housing 14 into a fastening receptacle 46 of the deflection element 44 .

FIG. 2 shows an enlarged view of the pump section including the housing discharge pipe 20 and the deflection element 44 .

The deflection element 44 defines an angled, in particular a right-angle, deflection channel 48 . The deflection channel 48 is fluidically connected to the housing outlet 24 and thus to the outlet side 32 of the pump unit 26 . The angled deflection channel 48 enables the deflection of the fluid flow discharged from the housing outlet 24 during operation of the pump unit 26 .

The deflection channel 48 comprises in particular three adjoining channel sections, namely an inlet channel section 50 close to the housing outlet, an outlet channel section 52 remote from the housing outlet and fluidly connecting the outlet channel section 52 with the inlet channel section 50 The middle channel section 54.

The inlet channel section 50 is arranged coaxially with the housing outlet 20 and is aligned (centre) with the housing outlet 24 such that the housing outlet 24 opens fluidly into the inlet channel section 50 . The inlet channel section 50 has an inlet section flow cross-sectional area A1 which is substantially equal to the outlet flow cross-sectional area A2 of the housing outlet opening 24 .

The central channel section 54 is designed perpendicular to the inlet channel section 50 . The intermediate channel section 54 has an intermediate section flow cross-sectional area A3 which is smaller than the inlet section flow cross-sectional area A1 of the inlet channel section.

The outlet channel section 52 is arranged coaxially to the central channel section 54 and is therefore perpendicular to the inlet channel section 50 . The outlet channel section 52 has an outlet section flow cross-sectional area A4 which is greater than the inlet section flow cross-sectional area A1 of the inlet channel section 50 and thus also the middle section flow cross-sectional area A3 of the intermediate channel section 54 . The flow cross-sectional area A4 of the outlet section is preferably at least twice, more preferably at least four times, the flow cross-sectional area A3 of the middle section.

The cylindrical fastening receptacle 46 enables the deflection element 44 to be mounted on the cylindrical housing outlet 20 with different rotational orientations relative to the central axis of the housing outlet 20 . The separate deflection element 44 can thus easily be connected to the pump housing 14 in different orientations in order to change the discharge direction of the deflection channel 48 relative to the pump housing 14 .

In FIG. 1 , the deflection element 44 is arranged in a first direction, wherein the outlet channel section 52 is located on the side of the housing outlet pipe 20 next to the housing cover, so that the deflection channel 48 directs the discharge flow towards the motor vehicle vacuum pump 10 The side next to the housing cover is deflected.

FIG. 3 shows a second possible orientation of the deflection element 44 , in which the deflection element 44 is rotated by 180° about the center axis of the housing outlet 20 compared to the first orientation. Outlet channel section 52 is located here on the side of housing outlet pipe 20 facing away from the housing cover, so that deflection channel 48 deflects the discharge flow away from the side next to the housing cover of motor vehicle vacuum pump 10 and thus towards the first Direction of opposite axial deflection.

It should be clear that the deflection element 44 according to the invention can also be connected to the pump housing 14 in any rotational orientation between the first orientation shown in FIG. 1 and the second orientation shown in FIG. 3 .

List of reference signs

10 Motor Vehicle Vacuum Pumps

12 Motor vehicle brake booster

14 Pump housing

16 Shell body

18 Housing cover

20 Case drain

22 Housing side wall

24 Case drain

26 pump unit

28 pump rotor

30 Suction side

32 Discharge side

34 check valve

36 discharge channel

38 electric motor

40 Rotor shaft

42 Pump control unit

44 deflection element

46 Fixed housing

48 deflection channels

50 entryway segments

52 Exit channel section

54 middle channel section

A1 Flow cross-sectional area of the inlet section

A2 Discharge port flow cross-sectional area

A3 Flow cross-sectional area of middle section

A4 Flow cross-sectional area of outlet section

Claims (7)

1. A motor vehicle vacuum pump (10), comprising - a pump unit (26) with a rotatable pump rotor (28) arranged to pump fluid from the suction side (30) of the pump unit (26) during pump operation to the discharge side (32), - a pump housing (14) with a housing outlet (24) fluidly connected to the outlet side (32) of the pump unit (26), and - a separate deflection element (44) connected to the pump housing (14) and defining a deflection channel (48) fluidly connected to the housing outlet (24) Connected and arranged to deflect fluid flow from said housing discharge opening (24) during pump operation. 2. The motor vehicle vacuum pump (10) according to claim 1, wherein the deflection element (44) can be connected to the pump housing (14) in different orientations. 3. Motor vehicle vacuum pump (10) according to one of the preceding claims, wherein the deflection element (44) is provided with a fixed receptacle (46), and wherein the pump housing (14) is provided with a protruding A housing discharge pipe (20) which defines a housing discharge opening (24) and is inserted into the fixed housing (46) in order to fasten the deflection element (44) in the above the pump housing (14). 4. The motor vehicle vacuum pump (10) according to one of the preceding claims, wherein the outlet channel section (52) of the deflection channel (48) facing away from the housing outlet is designed relative to the deflection channel (48 ) is angled at an inlet channel section (50) near the housing outlet, the outlet channel section (52) is preferably substantially perpendicular to the inlet channel section (50). 5. The motor vehicle vacuum pump (10) according to one of the preceding claims, wherein the inlet channel section (50) of the deflection channel (48) close to the housing outlet is provided with an inlet section flow cross-sectional area (A1 ), the inlet section flow cross-sectional area is smaller than the outlet section flow cross-sectional area (A4) of the outlet channel section (52) of the deflection channel (48) away from the housing outlet. 6. The automotive vacuum pump (10) according to claim 4 or 5, wherein said deflection channel (48) comprises an intermediate channel fluidly connecting said outlet channel segment (52) with said inlet channel segment (50) channel section (54), and wherein, said middle channel section (54) is provided with middle section flow cross-sectional area (A3), and said middle section flow cross-sectional area is smaller than the outlet section flow of said outlet channel section (52) The cross-sectional area (A4), preferably less than or equal to the inlet section flow cross-sectional area (A1) of said inlet channel section (50). 7. The motor vehicle vacuum pump (10) according to one of the preceding claims, wherein the deflection element (44) is produced from an elastic plastic, preferably rubber.

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