Motor vehicle vacuum pump

Abstract

The invention relates to a motor vehicle vacuum pump (10) comprising - a pump unit (26) with a rotatable pump rotor (28) which is provided for pumping fluid from a suction side (30) of the pump unit (26) to a discharge side (32) during pump operation, - a pump housing (14) with a housing discharge opening (24) which is fluidically connected to the discharge side (32) of the pump unit (26), and - a separate deflection element (44) which is connected to the pump housing (14) and defines a deflection channel (48) which is fluidically connected to the housing discharge opening (24) and is provided for deflecting a fluid flow discharged from the housing discharge opening (24) during pump operation. The separate deflection element (44) enables an easy adaptation of the spatial orientation of the atmospheric-side discharge opening to different mounting orientations, thereby reliably preventing a liquid accumulation in the discharge flow path. This provides a robust and versatile motor vehicle vacuum pump (10).

Description

Technical Field

[0001] This invention relates to a vehicle vacuum pump, and more particularly to an electric rotary vane vacuum pump that provides vacuum for a vehicle brake booster. Background Technology

[0002] Vehicle vacuum pumps are commonly used in motor vehicles to provide vacuum to the brake booster of the vehicle's braking system, particularly to provide vacuum to the vacuum chamber of the brake booster. A vehicle vacuum pump can be the sole vacuum source for the brake booster, or it can be used in combination with other vacuum sources, such as the intake system of an internal combustion engine.

[0003] Brake boosters utilize the pressure difference between their vacuum chamber and the surrounding atmospheric pressure to enhance the mechanical braking force generated by pressing the brake pedal, which mechanically actuates the vehicle's braking system. Therefore, providing sufficient vacuum to the brake booster's vacuum chamber is crucial for ensuring the reliable operation of the brake booster and, consequently, the reliable and convenient operation of the vehicle's braking system.

[0004] Document WO 2019 / 034256 A1 discloses, for example, a vehicle vacuum pump with a pump unit having a rotatable pump rotor configured to pump fluid from the suction side to the discharge side of the pump unit during pump operation. The vehicle vacuum pump also includes a pump housing with a housing discharge port, which is fluidly connected to the discharge side of the pump unit. If the vehicle vacuum pump is shut off after pump operation, ambient air is drawn into the pump housing via the housing discharge port due to the pressure difference between the at least partially evacuated pump housing and the ambient atmosphere. The disclosed vehicle vacuum pump has a special discharge passage with a sharply widened cross-section toward the discharge port to reduce the inflow velocity of ambient air at the discharge port during pump venting, thereby reducing the entry of moisture and particles into the pump housing. This provides a relatively durable vehicle vacuum pump.

[0005] However, the vehicle vacuum pump in document WO 2019 / 034256 A1 must be installed in the vehicle with the outlet facing downwards in a prescribed orientation to prevent liquids, such as condensate, from accumulating in the discharge passage. This prescribed installation orientation significantly limits the installation possibilities and therefore the application possibilities of the disclosed vehicle vacuum pump. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to provide a durable and versatile automotive vacuum pump.

[0007] The technical problem described herein is solved by a vehicle vacuum pump.

[0008] The vehicle vacuum pump according to the invention comprises a pump unit having a rotatable pump rotor. The pump rotor is arranged in a pump chamber and configured to pump 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 eccentrically arranged in the pump chamber and including a plurality of radially sliding rotor blades. During pump operation, the rotor blades radially contact the sidewalls of the pump chamber and define a plurality of rotating, fluid-separated pump chamber cavities that transport fluid from the suction side of the pump unit to the discharge side of the pump unit. The pump unit is constructed such that the volume of the pump chamber changes during its movement from the suction side to the discharge side, thereby compressing the delivered fluid.

[0009] The vehicle vacuum pump according to the invention also includes a pump housing, which includes a housing outlet. The pump housing typically comprises multiple housing portions defining multiple housing chambers. The pump housing typically defines at least a pump chamber and a motor chamber. The housing outlet is fluidly connected to the discharge side of the pump unit, such that fluid is discharged into the ambient atmosphere via the housing outlet during pump operation. The housing outlet may be a simple opening within the housing sidewall, or it may be defined by a housing discharge pipe / nozzle projecting from the housing sidewall. The housing outlet typically has a substantially circular opening cross-section.

[0010] According to the invention, the vehicle vacuum pump includes a separate deflecting element connected to the pump housing. This deflecting element defines a deflection channel that is fluidly connected to the housing outlet, allowing fluid to be discharged into the ambient atmosphere via the deflection channel during pump operation. The deflection channel preferably discharges directly into the surrounding atmosphere, thereby defining the final segment of the discharge flow path. The deflection channel is configured to deflect the fluid flow discharged from the housing outlet during pump operation; that is, the deflection channel is designed to change the flow direction of the fluid as it passes through the deflection channel. The discharge channel can, for example, be designed to be curved or angled. The discharge channel can also be designed to be straight but inclined relative to the discharge direction of the housing outlet. In any case, the deflection channel is designed such that the flow direction of the fluid flowing through the discharge channel is deflected relative to the flow direction of the fluid at the housing outlet.

[0011] The independent deflection element according to the invention can be easily adapted to different mounting orientations of automotive vacuum pumps. In particular, the deflection element can be easily designed such that, if an automotive vacuum pump is installed, the ambient atmosphere side end of the deflection channel is oriented downwards. This downward orientation of the deflection channel allows liquids, such as condensate, to drain from the deflection channel and also minimizes the amount of moisture and particles entering the pump housing during pump exhaust. The independent deflection element allows the automotive vacuum pump to be easily adapted to different mounting orientations and thus to different installation locations without requiring a redesign of the (complete) pump housing. Therefore, the independent deflection element according to the invention provides a durable and versatile automotive vacuum pump.

[0012] In a preferred embodiment of the invention, the deflecting element and / or pump housing are designed such that the deflecting element can be connected to the pump housing in different orientations relative to the pump housing. This enables different spatial orientations of the deflecting element, particularly different spatial orientations of the ends of the deflection channels on the ambient atmosphere side having the same deflecting element. This allows the automotive vacuum pump to be adapted to different installation locations by simply connecting the deflecting element to pump housings with different spatial orientations, and thus provides a versatile automotive vacuum pump.

[0013] Preferably, the deflecting element has a retaining portion, and the pump housing has a protruding housing discharge tube defining a housing outlet and inserting into the retaining portion to secure the deflecting element to the pump housing. This allows the deflecting element to be easily connected to the pump housing by "plugging" the housing discharge tube into the retaining portion of the deflecting element. The retaining portion and / or the housing discharge tube are preferably designed so that the deflecting element can be connected to the pump housing in different spatial orientations. More preferably, the retaining portion has a substantially cylindrical opening and the housing discharge tube has a corresponding substantially cylindrical outer surface, allowing the deflecting element to be connected with different rotational orientations relative to the housing discharge tube. The inner surface of the retaining portion and the outer surface of the housing discharge tube are typically designed to provide a circumferential frictional engagement or form engagement to prevent unintentional rotation of the deflecting element on the housing discharge tube. This provides a versatile automotive vacuum pump.

[0014] In a preferred embodiment of the 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, which is closer to the housing outlet. The outlet channel section is preferably substantially perpendicular to the inlet channel section. The inlet channel section is typically centered on the housing outlet. This angular deflection allows for a simple change in the spatial orientation of the ambient atmosphere side end of the deflection channel, and thus the discharge direction of the deflection element, by rotating the deflection element about the extending axis of the inlet channel section and therefore about the center of the outlet. This enables the vehicle vacuum pump to be easily adapted to different installation locations by rotating the deflection element, thereby providing a versatile vehicle vacuum pump.

[0015] Preferably, the inlet channel section of the deflection channel near the housing outlet has a smaller flow cross-sectional area than the outlet channel section of the deflection channel away from the housing outlet. The larger flow cross-sectional area of ​​the outlet channel section reduces the flow velocity at the outlet of the deflection channel relative to the inlet velocity on the housing outlet side. This reduces the ambient air inflow velocity at the outlet opening of the deflection channel during vacuum pump exhaust and thus significantly reduces moisture and particles entering the pump housing.

[0016] More preferably, the deflection channel includes an intermediate channel section that fluidly connects the outlet channel section and the inlet channel section, wherein the flow cross-sectional area of ​​the intermediate channel section is smaller than that of the outlet channel section, and preferably smaller than or equal to that of the inlet channel section. This further reduces moisture and particles entering the pump housing.

[0017] In a preferred embodiment of the invention, the deflecting element is made of elastic plastic, preferably rubber. The elastic deflecting element allows for a simple press-fit connection between the deflecting element and the pump housing. This ensures a reliable connection of the deflecting element without requiring any additional fixing devices. Attached Figure Description

[0018] Embodiments of the present invention are described with reference to the accompanying drawings, in which:

[0019] Figure 1 A vehicle vacuum pump according to the invention is shown, wherein the deflection element is arranged along a first direction.

[0020] Figure 2 Show Figure 1 An enlarged view of the pump section of a motor vehicle vacuum pump, and

[0021] Figure 3 Show Figure 1 A vehicle vacuum pump in which the deflection element is arranged in the opposite second direction. Detailed Implementation

[0022] Figure 1 A vehicle vacuum pump 10 is shown, which is used in a vehicle braking system to provide a vacuum to the vacuum chamber of a vehicle brake booster 12.

[0023] The vehicle vacuum pump 10 includes a generally cylindrical pump housing 14 having a canister-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 sidewall 22 of the housing body 16. The housing discharge pipe 20 is designed to be cylindrical and integrally formed with the housing sidewall 22. The housing discharge pipe 20 defines a circular housing discharge outlet 24 at its end remote from the housing sidewall.

[0024] The vehicle vacuum pump 10 includes a pump unit 26 disposed within a pump housing 14. The pump unit 26 includes a rotatable pump rotor 28 configured to pump fluid, particularly gas, from the suction side 30 of the pump unit 26 to the discharge side 32 of the pump unit 26 during pump operation. In the embodiment described, the vehicle 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.

[0025] The suction side 30 of pump unit 26 is fluidly connected to the vehicle brake booster 12, and in particular the vacuum chamber of vehicle brake booster 12, via check valve 34. Check valve 34 allows fluid to flow from vehicle brake booster 12 to pump unit 26 during pump operation, and prevents fluid from flowing from pump unit 26 to vehicle brake booster 12 if vehicle vacuum pump 10 is turned off.

[0026] The discharge side 32 of the pump unit 26 is fluidly connected to the housing outlet 24 of the housing discharge pipe 20 via the discharge channel 36 inside the housing.

[0027] The vehicle vacuum pump 10 also includes an electric motor 38 disposed in the pump housing 14. The electric motor 38 is configured to drive the pump rotor 28 via a rotor shaft 40 rotatably connected to the pump rotor 28. In this embodiment, the electric motor 38 is electronically commutated and configured to operate at a variable motor speed.

[0028] The vehicle vacuum pump 10 also includes a pump control unit 42, which is configured to control the electric motor 38. In the embodiment described, the pump control unit 42 is configured to provide closed-loop control of the variable motor speed of the electric motor 38.

[0029] The vehicle vacuum pump 10 also includes a separate, generally L-shaped deflection element 44 connected to the pump housing 14. In the embodiment described, the deflection element 44 is made of rubber and has a generally cylindrical retaining portion 46. The deflection element 44 is fixed to the pump housing 14 by a press-fit connection formed by pressing the housing discharge pipe 20 of the pump housing 14 into the retaining portion 46 of the deflection element 44.

[0030] Figure 2 An enlarged view of the pump section, including the housing discharge pipe 20 and the deflection element 44, is shown.

[0031] The deflection element 44 defines an angled, particularly right-angled, deflection channel 48. The deflection channel 48 is fluidly connected to the housing outlet 24 and thus to the discharge side 32 of the pump unit 26. The angled deflection channel 48 deflects the fluid flow discharged from the housing outlet 24 during operation of the pump unit 26.

[0032] The deflection channel 48 specifically includes three adjacent channel sections: an inlet channel section 50 near the housing outlet, an outlet channel section 52 away from the housing outlet, and an intermediate channel section 54 that fluidly connects the outlet channel section 52 to the inlet channel section 50.

[0033] The inlet channel section 50 is coaxially arranged with the shell discharge pipe 20 and aligned with the shell discharge outlet 24 (center), such that the shell discharge outlet 24 is fluid-accessed to 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 shell discharge outlet 24.

[0034] The intermediate channel section 54 is designed to be 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.

[0035] The outlet channel section 52 is coaxially arranged with the intermediate 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 larger than the inlet section flow cross-sectional area A1 of the inlet channel section 50 and is therefore also larger than the intermediate section flow cross-sectional area A3 of the intermediate channel section 54. The outlet section flow cross-sectional area A4 is preferably at least twice, more preferably at least four times, the intermediate section flow cross-sectional area A3.

[0036] The cylindrical fixed receiving portion 46 allows the deflection element 44 to be mounted on the cylindrical housing discharge pipe 20 with different rotational orientations relative to the central axis of the housing discharge pipe 20. The independent deflection element 44 can therefore be easily connected to the pump housing 14 in different orientations, thereby changing the discharge direction of the deflection channel 48 relative to the pump housing 14.

[0037] exist Figure 1 In the middle, the deflection element 44 is arranged along the first direction, wherein the outlet channel section 52 is located on one side next to the housing cover of the housing discharge pipe 20, so that the deflection channel 48 deflects the exhaust flow toward the side next to the housing cover of the motor vehicle vacuum pump 10.

[0038] Figure 3 A possible second orientation of the deflecting element 44 is shown, in which the deflecting element 44 is rotated 180° about the central axis of the housing discharge pipe 20 compared to the first orientation. The outlet channel section 52 is located here on the side of the housing discharge pipe 20 away from the housing cover, so that the deflecting channel 48 deflects the exhaust flow away from the side next to the housing cover of the vehicle vacuum pump 10 and thus deflects it axially opposite to the first orientation.

[0039] It should be clarified that the deflection element 44 according to the present invention can also be used as... Figure 1 The first orientation and shown Figure 3 Any rotational orientation between the second orientations shown is connected to the pump housing 14.

[0040] List of reference numerals

[0041] 10 Motor vehicle vacuum pumps

[0042] 12 Motor vehicle brake boosters

[0043] 14 Pump Casing

[0044] 16 Shell Body

[0045] 18. Shell cover

[0046] 20 Shell Discharge Pipe

[0047] 22 Shell sidewalls

[0048] 24 Shell Outlet

[0049] 26 pump units

[0050] 28 pump rotor

[0051] 30 suction side

[0052] 32 Exhaust Side

[0053] 34 Check Valve

[0054] 36 discharge channels

[0055] 38 electric motors

[0056] 40 rotor shaft

[0057] 42 Pump Control Unit

[0058] 44 deflection elements

[0059] 46 Fixed Receiving Section

[0060] 48 deflection channels

[0061] 50 entrance passage section

[0062] 52 Exit Channel Section

[0063] 54 Middle Channel Section

[0064] A1 inlet section flow cross-sectional area

[0065] A2 outlet flow cross-sectional area

[0066] A3 intermediate section flow cross-sectional area

[0067] A4 outlet section flow cross-sectional area

Claims

1. Motor vehicle vacuum pump (10), comprising - a pump unit (26) having a rotatable pump rotor (28) which is arranged for pumping fluid from a suction side (30) to a discharge side (32) of the pump unit (26) during pump operation, - a pump housing (14) having a housing discharge opening (24) which is fluidically connected to the discharge side (32) of the pump unit (26), and - a separate deflection element (44) which is connected to the pump housing (14) and defines a deflection channel (48) which is fluidically connected to the housing discharge opening (24) and is arranged for deflecting a fluid flow discharged from the housing discharge opening (24) during pump operation, wherein an inlet channel section (50) of the deflection channel (48) near the housing discharge opening is provided with an inlet section flow cross-sectional area (Al) which is smaller than an outlet section flow cross-sectional area (A4) of an outlet channel section (52) of the deflection channel (48) remote from the housing discharge opening.

2. 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 claim 1, wherein The deflection element (44) is provided with a fixed receptacle (46), and wherein the pump housing (14) is provided with a protruding housing discharge tube (20) which defines the housing discharge opening (24) and is inserted into the fixed receptacle (46) in order to fasten the deflection element (44) at the pump housing (14).

4. Motor vehicle vacuum pump (10) according to one of claims 1 to 3, wherein The outlet channel section (52) of the deflection channel (48) remote from the housing discharge opening is designed at an angle with respect to the inlet channel section (50) of the deflection channel (48) near the housing discharge opening.

5. Motor vehicle vacuum pump (10) according to claim 4, wherein The outlet channel section (52) is perpendicular to the inlet channel section (50).

6. Motor vehicle vacuum pump (10) according to claim 4, wherein The deflection channel (48) comprises an intermediate channel section (54) fluidically connecting the outlet channel section (52) with the inlet channel section (50), and wherein the intermediate channel section (54) is provided with an intermediate section flow cross-sectional area (A3) which is smaller than the outlet section flow cross-sectional area (A4) of the outlet channel section (52).

7. Motor vehicle vacuum pump (10) according to claim 6, wherein The intermediate section flow cross-sectional area (A3) is smaller than or equal to the inlet section flow cross-sectional area (Al) of the inlet channel section (50).

8. The motor vehicle vacuum pump (10) of claim 1, wherein, The deflection element (44) is made of an elastic plastic.

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