The invention is directed to a check valve arrangement, in particular to a check valve arrangement provided with a disc-shaped valve body. The invention is also directed to a motor vehicle vacuum pump being provided with such a check valve arrangement.

WO 2017/036548 A1 discloses a motor vehicle vacuum pump being provided with a check valve arrangement being arranged within the suction port of the vacuum pump. The disclosed check valve arrangement is provided with a valve housing which radially defines a valve body chamber. The check valve arrangement comprises a ring-shaped valve seat which is located at a first axial end of the valve body chamber and radially surrounds a valve inlet opening. The check valve arrangement also comprises a ring-shaped valve travel limiter which is located at a valve-seat-remote second axial end of the valve body chamber. The check valve arrangement also comprises a disc-shaped valve body being arranged within the valve body chamber. The valve body is axially preloaded by a preload spring towards the valve seat into a closed position. The fluid pressure within the check valve arrangement pushes the valve body against the preload spring towards the valve travel limiter into an open valve position, if the check valve arrangement is loaded in a forward flow direction. However, a relatively high open force is required to move the valve body against the preload spring into the open position. This reduces the pump performance of the vacuum pump. EP 1 927 786 B1 and DE 10 2012 200 492 A1 both disclose a check valve arrangement being provided with a loosely arranged valve body. The fluid pressure within the check valve arrangement pushes the valve body towards the valve travel limiter into the open valve position, if the check valve arrangement is loaded in a forward flow direction, and pushes the valve body towards the valve seat into the closed valve position, if the check valve arrangement is loaded inversely. However, the loosely- arranged valve body can tilt within the valve body chamber and, as a result, can become canted or jammed within the valve travel limiter. This avoids a reliable closing of the check valve arrangement if the flow direction inverses. The check valve arrangements disclosed in EP 1 927 786 B1 and DE 10 2012 200 492 A1 also provide only relatively low effective flow cross section so that the check valve arrangement allows only a relatively low fluid throughput in the open position.

It is an object of the invention to provide check valve arrangement which requires only a relatively low open force, which provides a relatively high fluid throughput in the forward flow direction, and which reliably stops a fluid flow in the inverse flow direction.

This object is achieved with a check valve arrangement with the features of claim 1.

The check valve arrangement according to the invention is provided with a valve housing which radially defines a valve body chamber. Preferably, the valve housing is provided to define a substantially cylindrical valve body chamber.

The check valve arrangement according to the invention is also provided with a valve seat which is located at a first axial end of the valve chamber and which radially surrounds a valve inlet opening. The valve seat can be provided integrally with the valve housing, but can alternatively be provided as a separate element being fixed at the valve housing. The valve seat is, preferably, provided at or close to an axial end of the valve housing.

The check valve arrangement according to the invention is also provided with a valve travel limiter which is located axially spaced from the valve seat at a valve-seat-remote second axial end of the valve body chamber. The valve travel limiter is located downstream of the valve seat in view of a desired forward flow direction of the check valve arrangement. The valve travel limiter can be provided integrally with the valve housing, but can be alternatively provided as a separate element being fixed at the valve housing, for example by press-fitting. The check valve arrangement according to the invention is also provided with disc-shaped valve body which is loosely arranged within valve body chamber, i.e. the valve body is able to move in an uninhibited manner within the extent of valve body chamber. In particular, the valve body is not preloaded in any way by any kind of spring element etc.

Preferably, the valve body is provided with a circular transversal geometry, but alternatively can be provided with any other transversal geometry. In any case, the valve body geometry corresponds with the valve seat geometry so that the valve body is able to fluid-tightly close the opening being defined by the valve seat. Preferably, the valve body is provided with a sealing lip element.

Typically, the valve body is provided with a diameter being significantly smaller compared to the inside diameter of the valve body chamber so that the fluid can axially flow around and pass the valve body efficiently in an open valve position of the check valve arrangement. The peripheral region of the valve body can also be provided with recesses or openings to minimize the cross-section area of the valve body. However, the cross- section area of the valve body has to be large enough to ensure a reliable total fluidic closing of the valve seat opening.

The valve body is axially moved between the open valve position and a closed valve position only by the fluid pressure. If the valve arrangement is loaded in the forward flow direction, the valve body is moved into the open valve position, in which the valve body is axially pressed against the valve travel limiter. If the valve arrangement is loaded in the forward flow direction, the valve body is moved into the closed valve position, in which the valve body is axially pressed against the valve seat. However, the valve body is only pressed against the valve seat as long as the valve arrangement is loaded in the inverse flow direction. As a result, if the valve arrangement is loaded in the forward flow direction, almost no opening force is required to move the valve body away from the valve seat into the open position.

According to the invention, the valve travel limiter is provided with a support ring which is directly fixed to the valve housing. The support ring can be, for example, press-fitted in the valve housing. The support ring provides a reliable fixation of the valve travel limiter at the valve housing.

The valve travel limiter is also provided with a central transversal platform structure which axially protrudes from a valve-seat-facing side of the support ring. The platform structure provides a defined contact area for the valve body in the open valve position. In particular, the platform structure is designed in that way that a canting or jamming of the valve body within the valve travel limiter is reliably avoided. Preferably, the diameter of the platform structure is smaller compared to the diameter of the valve body and/or the platform structure is provided with axial incident flow openings. This ensures a defined incident flow at the limiter-facing valve body backside in case of an inverse fluid flow direction. As a result, the valve travel limiter according to the invention ensures a closing of the valve seat opening if the fluid flow direction within the check valve arrangement inverses so that a fluid flow in the inverse flow direction is immediately and reliably stopped.

The valve travel limiter is also provided with a platform frame which axially connects the central transversal platform structure with the support ring to reliably fix the platform structure at the support ring and, as a result, at the valve housing. According to the invention, the platform frame is provided with at least one radial frame opening which allows a radial fluid flow through the valve travel limiter. The flow cross section of the frame opening can be increased in a simple way by increasing the axial height of the platform frame. As a result, the valve travel limiter can be designed in that way that the effective flow cross section of the valve arrangement is not limited by the valve travel limiter, but only by the valve body geometry. The check valve arrangement according to the invention therefore allows a relatively high fluid throughput in the forward flow direction.

In a preferred embodiment of the invention, the platform frame is composed of several axially extending platform pillars circumferentially defining several radial frame openings between them. The platform pillars are, preferably, equidistantly distributed along the circumference of the platform structure and are provided with a relatively small circumferential width. The platform pillars provide a mechanically robust support of the platform structure at the support ring. However, the platform pillars only cover a relatively small circumferential area so that the frame openings have a relatively large cross section and, as a result, allow a high fluid throughput. Preferably, the platform structure is substantially star-shaped with several platform arms extending radially outwardly from a central hub element. The platform arms are, preferably, distributed equidistantly along the circumference of the platform structure. The platform arms circumferentially define several axial incident flow openings. The platform arms and the central hub element reliably avoid a jamming or canting of the valve body within the valve travel limiter. The incident flow openings between the platform arms ensure a defined axial incident flow at the valve body if the flow direction within the check valve arrangement inverses. As a result, this platform structure design ensures a reliable valve body movement into the closed valve position and, as a result, ensures an immediate and reliable interruption of an inverse fluid flow. More preferably, each radial platform arm is fixed to the support ring by a corresponding axial platform pillar. The platform arms and the platform pillars are, preferably, provided with the same axial width. This provides a mechanically robust valve travel limiter which allows a high fluid throughput in the forward flow direction and also ensures a reliable valve body movement towards the closed valve position if the fluid flow direction is inversed.

In a preferred embodiment of the invention, the circumferential width of the platform arms increases from the central hub element towards the radial outside. This reliably avoids a canting or jamming of the valve body within the platform structure and also allows a relatively homogeneous incident flow at the valve body backside through the platform structure. This ensures a reliable valve body movement towards the closed valve position if the fluid flow direction is inversed. Preferably, the support ring is provided with several axial support ring openings being arranged along the circumference of the support ring. The support ring openings are, preferably, distributed equidistantly along the circumference. The support ring openings increase the effective flow cross section of the valve travel limiter and, as a result, increases the fluid throughput of the check valve arrangement in the forward flow direction.

The check valve arrangement according to the invention can be provided within a motor vehicle vacuum pump, wherein the check valve arrangement is provided at a suction port of the vacuum pump. The vacuum pump is utilized to provide a vacuum to a motor vehicle pneumatic system, as for example a pneumatic vehicle brake system. The check valve arrangement according to the invention allows a fast and efficient depressurizing of the pneumatic system by the vacuum pump and reliably avoids a vacuum breach via the pump, if the pump stops and is inactive.

An embodiment of the invention is described with reference to the enclosed drawings, wherein

figure 1 shows a longitudinal section of a check valve arrangement according to the invention in an open valve position,

figure 2 shows the check valve arrangement of figure 1 in a closed valve position,

figure 3 shows a perspective representation of a valve travel limiter of the check valve arrangement of figure 1, and

figure 4 shows a simplified representation of a motor vehicle vacuum pump according to the invention, wherein the check valve arrangement of figure 1 is provided at a suction port of the vacuum pump. The described check valve arrangement 10 comprises a pot-shaped valve housing 12 with an integral valve seat 14, a valve travel limiter 16 being fixed within the valve housing 12, and a disc-shaped valve body 18 being loosely arranged within the valve housing 12.

The valve housing 12 comprises a cylindrical housing sidewall 20 and a transversal housing base 22. The housing sidewall 20 radially defines a valve body chamber 24, and the housing base 22 defines the valve body chamber 24 in a first axial direction. The housing base 22 is provided with a valve inlet opening 26 and defines the valve seat 14 which radially surrounds the valve inlet opening 26. As a result, the valve seat 14 is located at a first axial end 28 of the valve body chamber 24.

The valve travel limiter 16 comprises a support ring 30, a platform structure 32 axially protruding from a valve-seat-facing axial side of the support ring 30, and a platform frame 34 axially connecting the platform structure 32 with the support ring 30. The valve travel limiter 16 is located at a valve-seat-remote second axial end 36 of the valve body chamber 24. The valve travel limiter 16 is press-fitted into the valve housing 12 so that the support ring 30 of the valve travel limiter 16 engages into a circumferential support groove 38 provided at the radial inside of housing sidewall 20.

The support ring 30 is provided with several axial support ring openings 40 being distributed along the circumference of the support ring 30. The radial outside of the support ring 30 is provided with a mounting recess 42 which simplifies the press-fitting of the valve travel limiter 16 into the valve housing 12. The platform structure 32 is provided substantially star-shaped with a central hub element 44 and several platform arms 46 extending radially outwardly from a central hub element 44. The platform arms 46 are provided in that way that their circumferential width W continuously increases from the hub element 44 towards the radial outside. The platform arms circumferentially define several axial incident flow openings 47 which allow an axial fluid flow through the platform structure 32. The hub element 44 is provided with an additional axial incident flow opening 49 located at the center of the hub element 44.

The platform frame 34 is composed of several axially extending platform pillars 48, wherein each platform pillar 48 axially connects a platform arm end 50 with the support ring 30. The platform pillars 48 circumferentially define several radial frame openings 52 between them, which allow a radial fluid flow through the platform frame 34. The radial frame openings 52 of the platform frame 34 and the axial incident flow opening 47 of the platform structure 32 merge into each other seamlessly.

The disc-shaped valve body 18 is loosely arranged within the valve body chamber 24 being axially defined by the valve seat 14 at the first axial end 28 and by the valve travel limiter 16 at the opposite second axial end 36. The valve body 18 is provided with a ring-shaped sealing lip element 54 located at the valve-seat-facing axial side of the valve body 18.

The valve body 18 is able to move in an uninhibited manner within the extent of valve body chamber 24. If the check valve arrangement 10 is provided with a fluid flow in a forward flow direction F, the fluid pressure pushes the valve body 18 against the valve travel limiter 16 into an open valve position as shown in figure 1. In the open valve position, the valve body 18 is in contact with the valve travel limiter 16 so that the valve body 18 does not cover the valve inlet opening 26. As a result, fluid can flow via the valve inlet opening 26 into the valve body chamber 24. The fluid can flow axially around the radial outside of the valve body 18 towards the valve travel limiter 16 and can flow through the valve travel limiter 16 via the radial frame openings 52 as well as via the axial support ring opening 40 towards a valve outlet opening 56. The radial frame openings 52 and the axial support ring opening 40 provide a relatively large effective flow cross section so that the check valve arrangement 10 according to the invention allows a relatively high fluid throughput in the forward flow direction F.

If the check valve arrangement 10 is provided with a fluid flow in an inverse flow direction I, the fluid pressure pushes the valve body 18 against the valve seat 14 into a closed valve position as shown in figure 2. In the closed position, the valve body is pressed against the valve seat 14 so that the sealing lip element 54 fluid-tightly closes the opening being defined by the valve seat 14 and, as a result, avoids a fluid flow from the valve body chamber 24 towards the valve inlet opening 26. Since the valve body 18 cannot become canted or jammed within the valve travel limiter 16, the check valve arrangement 10 according to the invention reliably interrupts a fluid flow in the inverse flow direction I. Figure 4 shows a motor vehicle vacuum pump 110 comprising a pump unit 112 with a suction port 114 and a pressure port 116. The pump unit 112 can be, for example, an electrically or mechanically driven rotary vane pump. In the present embodiment of the invention, the suction port 114 is fluidically connected to a motor vehicle brake system 118 to provide a vacuum for actuating the brake system 118.

The vacuum pump 110 is provided with the check valve arrangement 10 being described above. The check valve arrangement 10 is provided within the suction port 114, wherein the check valve arrangement 10 arranged in that way that the forward flow direction F points towards the pump unit 112 and the inverse flow direction I points towards the brake system 118. As a result, the check valve arrangement 10 allows a fluid flow from the brake system 118 into the pump unit 112, but blocks an inverse fluid flow from the pump unit 112 into the brake system 118. The check valve arrangement 10 therefore avoids a vacuum breach within the brake system 118 in case of a stopped and inactive vacuum pump 110.

Reference List

10 check valve arrangement 12 valve housing

14 valve seat

16 valve travel limiter

18 valve body

20 housing sidewall

22 housing base

24 valve body chamber

26 valve inlet opening

28 first axial end

30 support ring

32 platform structure

34 platform frame

36 second axial end

38 support groove

40 support ring openings 42 mounting recess

44 hub element

46 platform arms

47 incident flow openings

48 platform pillars

49 incident flow opening

50 platform arm ends

52 frame openings

54 sealing lip element

56 valve outlet opening

58 vacuum pump

110 motor vehicle vacuum pump 112 pump unit 114 suction port

116 pressure port

118 motor vehicle brake system

F forward flow direction

I inverse flow direction

W circumferential platform arm width