Air diverter valve

Abstract

The present invention relates to an air diverter valve having a flow housing (36) with a flow channel (38) between an inlet (40) and an outlet (42), a valve seat (44) formed between the inlet (40) and the outlet (42), an actuator (10), a drive member (28) movable translationally by the actuator (10), and a control body (34) fixed to the drive member (28), which includes a circumferentially closed outer cover surface (46) on the radially outer side, at the axial end of which a circumferential support edge (56) is formed, which can be placed on the valve seat (44) and lifted off the valve seat (44), wherein the control body (34) includes a radially inner axial inflow surface (66) on the axially side facing away from the drive member (28), and includes a wall (54) which extends at least radially inwards from the outer cover surface (46) and in which at least one opening (64) is formed, through which the interior space (94) of the air diverter valve is fluidly connected to the flow channel (38). According to the invention, the radially outer annular outflow edge (78) of the axial inflow surface (66) is axially offset relative to the support edge (56) to such an extent in the axial direction that a first vector (84) extending radially outwards from the outflow edge (78) to the nearest point of the support edge (56) encloses an angle of at most 15° with the plane spanned by the support edge (56), and the at least radially extending wall (54) having at least one opening (64) is axially offset in the direction of the drive member (28) relative to the support edge (56) and relative to the outflow edge (78).

Description

Field of the Invention

[0001] The present invention relates to an air diverter valve having a flow housing with a flow passage between an inlet and an outlet, a valve seat formed between the inlet and the outlet, an actuator, a drive member movable translationally by the actuator, and a control body fastened to the drive member, the control body including a circumferentially closed outer cover surface on the radially outer side, having a circumferential bearing edge formed at its axial end, the bearing edge being placeable on and liftable from the valve seat, wherein the control body includes a radially inner axial inflow surface on the axial side remote from the actuating member and includes a wall extending at least radially inwardly from the outer cover surface, in which at least one opening is formed through which the interior space of the air diverter valve is fluidly connected to the flow passage. Background Art

[0002] Air diverter valves are used in a known manner to recirculate compressed fresh gas, possibly also recirculated exhaust gas, from the pressure side of a compressor of a turbocharger to the suction side of the compressor. When an internal combustion engine transitions from high-load operation to over-load operation, it is necessary to connect the exhaust side and the suction side of the compressor via a bypass pipe to prevent the high delivery rate of the compressor of the turbocharger to a closed throttle valve and the resulting pumping effect.

[0003] Air diverter valves are typically electromagnetically actuated, wherein the control body of the valve is moved by an armature under the action of an electromagnetic force. A generic air diverter valve is known, for example, from DE 10 2016 118 341 A1. The valve includes a pressure compensation port connected to the control body of the armature, and by appropriate design of the effective surface, a force balance is established with respect to the aerodynamic forces acting on the control body, so that for actuation, only the force of the spring needs to be overcome. Thus, the air diverter valve has a very short actuation time (Stellzeiten). In this valve, the closing body is directly connected to the armature, and the interior of the valve is separated from the outside by a diaphragm. However, the problem is that in a very short stroke starting from the closed position, due to the dynamic pressure generated, the static pressure drops very quickly, which results in a large force acting on the control body in the closing direction.

[0004] In previous generations of air diverter valves, such as those described in EP 1 762 712 B1, attempts have been made to also transfer this low static pressure generated during the opening process to the opposite side of the control body by bringing the opening directly to the narrow opening region. However, this results in the need to provide a relatively large spring force for closing, and thus also a relatively large force for starting the opening movement by the electromagnet, and the electromagnet must also be designed correspondingly large. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to provide an air steering valve. On the one hand, it can achieve a very fast driving time, and on the other hand, it requires a lower electromagnetic driving force, so that the installation space of the air steering valve can be reduced, especially the space of the electromagnet, and thus the air steering valve can be manufactured at a lower cost.

[0006] The control body of the air steering valve according to the present invention includes a radially outer, circumferentially closed outer cover surface. A circumferential support edge is formed at the axial end of the outer cover surface. This support edge can be placed on the valve seat and can be lifted from the valve seat. Here, the support edge should be understood as a narrow annular surface that tapers towards the valve seat. The control body further includes an axially inward inflow surface on the axial side away from the drive component. This inflow surface is at least indirectly connected to the outer cover surface through at least a radially extending wall. At least one opening is formed in this wall. Through this opening, the interior of the air steering valve is fluidly connected to the flow channel, so that at least when the control body is not moved, the same pressure exists below and above the control body. The radially outer outflow edge of the axially inward inflow surface is offset from the support edge in the axial direction by at most such an amount that the first vector from the radially outer outflow edge to the nearest point of the support edge encloses an angle of at most 15° with the plane spanned by the support edge. This means that there is only a slight axial offset between the outflow edge of the inflow surface and the support edge of the control body. As a result, when the valve is first opened, the air flow is generally directed towards the free gap between the valve seat and the support edge of the control body. In addition, the at least radially extending wall having at least one opening is axially offset in the direction of the drive component from the support edge and the outflow edge. Due to the axial distance between the wall and the support edge, during the opening process, the pressure difference generated by the flow and acting in the closing direction only acts on the thin support edge, so that only a very small closing force acts on the control body. Through the fluid guiding towards the gap and the small available force-bearing surface relative to the generated pressure, a uniform force curve is generated during the opening process, and the required opening force is very low. Therefore, the electromagnet can be made smaller, but still can achieve fast opening and closing.

[0007] Preferably, the tangential vector at a point on the radially outer outflow edge points to an area that is axially adjacent to the support edge and away from the drive component. It can be seen from this that when the opening process starts, the flow directly enters the gap between the valve seat and the support edge, which greatly reduces the force acting on the control body in the closing direction due to the air flow.

[0008] Advantageously, at least the radially extending wall is offset in the direction of the drive member to such an extent that a second vector from the at least radially extending wall radially outwards in the radial direction to the bearing edge encloses an angle of at least 20° with the plane spanned by the bearing edge. As a result, the wall returns to such an extent that the pressure dropping in the gap cannot act directly on the wall surface, thereby reducing the force acting on the control body in the closing direction. Here, radially outwards is only understood to mean that the vector includes a radial component which points away from the centre line of the air diverter valve. However, there will of course also be an axial extension component of the vector. This applies to all vectors mentioned in the present application, which by definition all point radially outwards.

[0009] Furthermore, it is preferred that the opening is offset in the direction of the drive member to such an extent that a third vector from the opening radially outwards in the radial direction to the bearing edge includes an angle of at least 30° with the plane spanned by the bearing edge, and a fourth vector from the flow edge radially outwards in the radial direction to the opening includes an angle of at least 30° with the plane spanned by the bearing edge. In this way, even in the case of sudden position changes and the resulting pressure changes on the surface facing the inlet at the two axial ends of the opening, the force balance can be maintained, thus enabling short drive times and requiring low drive forces.

[0010] Preferably, the circumferentially closed outer cover surface is formed by the radially outer and axially valve seat-facing regions of the cylinder and the inner hollow body, to which the cylinder is fixed, wherein the inner hollow body is movably coupled to the drive member and includes a wall having at least one opening and a bearing edge. This embodiment facilitates the assembly of the control body.

[0011] In a preferred embodiment, an axially inflowing surface is formed on the inflow element, which has a closed bottom facing the drive member and an open axial end remote from the drive member, on which a radially outer outflow edge is formed. Thus, the inflowing surface is formed by an approximately pot-shaped body, which is easy to manufacture and facilitates the connection of the control body to the drive member by fixing the bottom centrally by welding to the drive member.

[0012] In a further embodiment of the invention, a radially outer outflow edge is formed on a collar (Kragen) which extends radially outwards and, if necessary, axially from the open axial end of the inflow element. In this way, a correspondingly aligned outflow edge can be provided without the need for additional components.

[0013] Here, preferably, the axial distance of the collar from the drive member is greater than the axial distance of the bearing edge from the drive member, and the collar extends only radially outwards in the radially outer region. In this case, the flow will be guided radially outwards and thus into the gap between the valve seat and the bearing edge during the initial opening process.

[0014] In another embodiment, the axial distance of the collar from the drive member is smaller than the axial distance of the bearing edge from the drive member, and the collar extends radially outwards and axially away from the drive member in the radially outer region. In this case, the outflow edge also points towards the gap between the control body and the valve seat immediately after the start of the opening process. In these two alternative embodiments, compared to the known embodiments, the closing force acting on the control body is reduced shortly after the start of the opening process.

[0015] Preferably, the inner hollow body includes an insert that is at least partially coated with elastomeric plastic, wherein the inner hollow body can be lowered onto the valve seat together with the plastic and abuts against the drive member. This plastic coating of the bearing edge ensures the tightness of the valve seat because minor irregularities can be compensated for by the elasticity. The plastic coating in the region of abutment against the drive member ensures that the control body can be tilted slightly towards the drive member, which also results in an improvement in the tightness.

[0016] For this purpose, the inflow element is fixed to the drive member with the bottom. The bottom can be fixed to the drive member by simple laser welding.

[0017] To fix the entire control body, the inflow element includes a radially expanded portion by means of which the inflow element abuts against the radially constricted portion of the inner hollow body at least in the open state. The inner hollow body can be tilted slightly relative to the inflow element fixed to the drive member, and thus be slightly tilted relative to the outer shroud surface and the bearing edge on the outside.

[0018] Particularly advantageous manufacturing results if the cylinder, the inner hollow body and the inflow element are manufactured as deep-drawn parts from sheet metal.

[0019] Preferably, the actuator is an electromagnet and the drive member is the armature of the electromagnet. This allows for a shorter drive time.

[0020] Thereby, an air diverter valve is achieved which has high durability and tightness. However, most importantly, the size and manufacturing cost of the electromagnet can be greatly reduced because the force to be overcome during the opening process is reduced by a special outflow from the inflow element, which is achieved by, on the one hand, optimizing the direction of the flow and, on the other hand, reducing the available force-bearing surface for the pressure difference. Description of the Drawings

[0021] An embodiment of the air diverter valve according to the invention is shown in the figures and described below.

[0022] Figure 1 A side view of the air diverter valve according to the invention is shown. Detailed Description

[0023] The air diverter valve shown in the figure includes an actuator 10 designed as an electromagnet, in whose housing 12 a coil 14 is wound around a coil carrier 16. A magnetizable iron core 18 is fixed in the radially inner region of the coil carrier 16, the axial ends of which project beyond the coil carrier 16, where the iron core 18 is surrounded at this axial end by a check plate 20 which is connected to an iron sheath 22 surrounding the coil 14. Another check plate 24 is located at the end of the coil carrier 16 opposite the iron core 18, which check plate 24 contacts the iron sheath 22 in the radially outer region and contacts a sliding bushing 26 extending into the coil carrier 16 in the radially inner region. An armature serving as a drive member 28 is supported in the sliding bushing 26. When the coil 14 is energized, the armature is attracted by an electromagnetic force to the iron core 18 and into its recess 30. The power supply is provided to the coil 14 via contacts which lead to a plug 32.

[0024] A control body 34 is fixed to the drive member 28, by means of which control body 34 the flow cross-section of a flow channel 38 formed in a flow housing 36 and connecting an inlet 40 and an outlet 42 can be opened or closed, in such a way that the control body 34 is lowered onto a valve seat 44 surrounding the flow cross-section or lifted therefrom.

[0025] The control body 34 includes a radially outer, circumferentially closed cylindrical outer cover surface 46, which is formed by a radially outer cylinder 48, which is made, for example, from a deep-drawn metal sheet, and includes a region 50 of the radially outer and axially valve-seat 44-facing region of an inner hollow body 52.

[0026] The inner hollow body 52 includes an insert 51 which can be manufactured from a metal sheet by deep drawing and has a wall 54 which has at least one radially inwardly extending portion or which extends at least partially radially inwards. To form the inner hollow body 52, the insert 51 is coated with an elastomeric plastic 53, which forms a support edge 56 in the radially outer and axially valve-seat 44-facing region 50, by means of which support edge the control body 34 is supported on the valve seat 44 in the closed state of the air diverter valve. The effective diameter supported on the valve seat 44 corresponds essentially to the diameter of the circumferentially closed outer cover surface 46, whereby an aerodynamic force balance acting on the control body 34 is established in the static state.

[0027] The wall 54 of the inner hollow body 52 is cylindrical in the first part 58. Adjacent to this cylindrical part 58 is a radially constricted part 60, and another cylindrical part 62 extends from the inner radius of the constricted part 60 in the direction of the drive member 28. This other cylindrical part 62 has a correspondingly smaller diameter compared to the first cylindrical part 58. At the axial end of the first part 58, the cylindrical part 62 bends slightly inwards. In the region of the radially constricted part 60, a plurality of axial holes are formed, and these axial holes serve as openings 64 that allow pressure equalization between the bottom and the top of the control member 34.

[0028] Except for the opening 64, the cylindrical parts 58, 62 and the constricted part 60 are coated with an elastomer 53, and the elastomer plastic 53 projects axially beyond the cylindrical part 62 in the direction of the drive member 28.

[0029] The control body 34 further includes a radially inner axial inflow surface 66 which, in the present embodiment, is formed on an inflow element 68 and serves to fix the control body 34 to the drive member 28. The inflow element 68 can also be formed by deep drawing and is substantially pot-shaped, with a bottom 70 arranged in a central circular groove 72 at the axial end of the drive member 28 and fixed in place by welding. A cylindrical portion 74 adjacent to the bottom 70 extends to the end of the elastomeric plastic 53 on the inner hollow body 52 facing away from the drive member 28 and has an outer diameter smaller than the inner diameter of the elastomer 53. On the axial side opposite to the bottom 70, a radially expanded portion 76 is annularly adjacent to the cylindrical portion 74 and projects radially beyond the elastomer 53, so that its outer diameter is larger than the inner diameter of the constricted portion 60 of the inner hollow body 52. Here, the distance between the radially expanded portion 76 and the bottom 70 of the inflow element 68 is selected such that when the inner hollow body 52 abuts against the drive member 28, a small gap is maintained between the elastomer 53 surrounding the constricted portion 60 of the inner hollow body 52 and the expanded portion 76 of the inflow element 68, so that the outer shroud surface 46 can be tilted slightly towards the inflow element 68 and thus also towards the drive member 28. Thus, a universal joint connection between the control body 34 and the drive member 28 is achieved. Starting from the radially outer end of the radially expanded portion 76, the inflow element 68 extends axially just in front of the support edge 56. The end of the inflow element 68 remote from the bottom 70 is formed as a ring 77 which extends slightly axially and radially. The radially outer end thereof forms an annular outflow edge 78 through which the flow onto the radially inner axial inflow surface 66 of the inflow element 68 is deflected in the direction of the outlet 42, where the radially inner axial inflow surface 66 is formed by the portion of the inflow element 68 which is axially oriented towards the inlet 40 and extends substantially radially. More specifically, it is specified that the tangential vector 8 of the outflow edge 78 (i.e., the tangent to the surface of the ring 77 in the radially outer region facing the inlet 40) points to a region slightly further away from the actuator 10 than the support edge 56. Thus, when the valve is slightly opened, this vector points to the gap between the valve seat 44 and the support edge 56.

[0030] In addition to this orientation of the outflow edge 78 relative to the support edge 56 and the side guide tube connected thereto, their arrangement relative to each other is also important. For example, the outflow edge 78 should be axially offset from the support edge 56 to such an extent that the angle enclosed by a first vector 84 pointing radially outwards from the outflow edge 78 to the support edge 56 and the plane 86 spanned by the support edge 56 is at most 15°, where this angle is independent of the direction from which it is measured. In the present example, relative to the support edge 56, the outflow edge 78 is arranged to be slightly offset relative to the drive member 28, where an angle of approximately 8° is produced.

[0031] In addition, the arrangement of the wall 54 and the opening 64 relative to the support edge 56 and the outflow edge 78 has a significant impact. Thus, a second vector 88 extending radially outward from any point on the wall 54 in the direction of the support edge 56 should enclose an angle of at least 20° with the plane 86 spanned by the support edge 56. In the present embodiment, this angle is between 40° and 70°.

[0032] In addition, the angle between a third vector 90 extending radially outward from one of the openings 64 to the support edge 56 and the plane 86 should also be at least 30°. In the present embodiment, this is approximately 60°. Further, the angle between a fourth vector 92 extending radially outward from the outflow edge to one of the openings 64 and the plane 86 should be at least 30°. In the present embodiment, this angle is approximately 66°.

[0033] This arrangement of the outflow edge 78, the support edge 56, the wall 54, and the opening 64 relative to each other results in the reduced pressure generated by the flow in the gap between the valve seat 44 and the control body 34 having little force-receiving surface during the opening process. Additionally, the pressure difference originally generated by the flow is also reduced by directing the flow into the gap.

[0034] In addition, an internal space 94 is formed in the housing 12 of the air diverter valve into which the control body 34 can slide when the valve is actuated. The internal space 94 is radially bounded by the housing wall 96, and an annular plate 98 is fixed at its end remote from the actuator 10, the inner diameter of which is slightly larger than the outer diameter of the shroud surface 46. A V-shaped seal 100 is provided on the plate 98, which has two legs, the first leg contacting the circumferentially enclosed shroud surface 46 and the second leg contacting the radially bounding housing wall 96. Thus, in the closed state of the valve, the internal space 94 is completely connected to the underlying inlet 40 through the opening 64. In order to also provide a corresponding pressure to the central groove 30 between the drive member 28 and the iron core 18, thereby enabling a pressure-balanced valve, one or more grooves are arranged on the outer circumference of the drive member 28.

[0035] In addition, a spring 102 is arranged inside the shroud surface 46, axially abutting against the wall 54 and its opposite axial end abutting against the housing 12 of the actuator 10. Thereby, when the coil 14 is de-energized, the control body 34 is placed in its state of resting on the valve seat 44. In this static state, there is a balance of forces such that the spring 102 can be designed to keep the air diverter valve in the closed state even when pressure pulsations occur.

[0036] For opening, the actuator 10 is energized, and only the force of the spring 102 needs to be overcome. Once the gap between the valve seat 44 and the bearing edge 56 is opened, flow is formed through this gap. The influence of the resulting static pressure fluctuations is largely avoided because the wall 54 is far enough away from the valve seat 44 and only the thin bearing edge 56 can act as the force-receiving surface for the pressure difference. Pressure equalization can also occur in the interior space 94 because, through the diversion tube, with the aid of the inflow element 68, no flow acts directly on the opening 64. Accordingly, rapid static pressure equalization can occur immediately upon opening, which would otherwise be suppressed and would thereby result in an additional force acting in the closing direction.

[0037] Therefore, very fast actuation times can be achieved with very small, and thus inexpensively producible, electromagnets.

[0038] It should be clear that the invention is not limited to the described embodiments. Thus, different actuators can also be used, or the outer cover surface and at least the radially extending wall can be manufactured in one piece. Additionally, if necessary, the inflow element can be manufactured in one piece with other parts of the control body or have a different structural design, since especially the arrangement of the outflow edge is functionally important. Additionally, if necessary, the elastomer can be dispensed with or used only in the bearing area.

Claims

1. An air diverter valve having a flow housing (36) having a flow channel (38) between an inlet (40) and an outlet (42), a valve seat (44) formed between the inlet (40) and the outlet (42), an actuator (10), a drive member (28) capable of translational movement by the actuator (10), a control body (34) fixed to the drive member (28), which includes a circumferentially closed outer cover surface (46) on the radially outer side, and a circumferential support edge (56) is formed at the axial end of the outer cover surface, and the support edge can be placed on the valve seat (44) and can be lifted from the valve seat (44), wherein the control body (34) includes a radially inner axial inflow surface (66) on the axial side oriented away from the drive member (28), and includes a wall (54) that extends at least radially inward from the outer cover surface (46), and at least one opening (64) is formed in the wall, through which the internal space (94) of the air diverter valve is fluidly connected to the flow channel (38), characterized in that the radially outer annular outflow edge (78) of the axial inflow surface (66) is maximally offset in the axial direction relative to the support edge (56) to such an extent that a first vector (84) extending radially outward from the outflow edge (78) to the nearest point of the support edge (56) encloses an angle of at most 15° with the plane spanned by the support edge (56), and the at least radially extending wall (54) having at least one opening (64) is axially offset in the direction of the drive member (28) relative to the support edge (56) and relative to the outflow edge (78), wherein the axial inflow surface (66) is formed on an inflow element (68) having a closed bottom (70) oriented towards the drive member (28) and an open axial end oriented away from the drive member (28), and a radially outer outflow edge (78) is formed at the axial end.

2. The air diverter valve according to claim 1, characterized in that a tangential vector (82) at a point on the radially outer outflow edge (78) points to a region that is axially adjacent to the support edge (56) and away from the drive member (28).

3. The air diverter valve according to claim 1 or 2, characterized in that the at least radially extending wall (54) is offset in the direction of the drive member (28) to such an extent that a second vector (88) extending radially outward from the at least radially extending wall (54) to the support edge (56) encloses an angle of at least 20° with the plane (86) spanned by the support edge (56).

4. The air diverter valve according to claim 1 or 2, characterized in that The at least one opening (64) is offset in the direction of the drive part (28) to such an extent that a third vector (90) from the at least one opening (64) radially outwards to the bearing edge (56) encloses an angle of at least 30° with the plane (86) spanned by the bearing edge (56), and a fourth vector (92) from the outflow edge (78) radially outwards to the opening (64) encloses an angle of at least 30° with the plane (86) spanned by the bearing edge (56).

5. The air diverter valve according to claim 1 or 2, characterized in that the circumferentially closed outer cover surface (46) is formed by a cylinder (48) and a radially outer and axially valve seat (44)-oriented region (50) of an inner hollow body (52) on which the cylinder (48) is fixed, wherein the inner hollow body (52) is movably coupled to the drive part (28) and comprises a wall (54) having at least one opening (64) and a bearing edge (56).

6. The air diverter valve according to claim 1 or 2, characterized in that the radially outer outflow edge (78) is formed on an annulus (77) which extends radially outwards and axially from the open axial end of the inflow element (68).

7. The air diverter valve according to claim 6, characterized in that the axial distance between the annulus (77) and the drive part (28) is greater than the axial distance between the bearing edge (56) and the drive part, and the annulus extends only radially in the radially outer region.

8. The air diverter valve according to claim 6, characterized in that the axial distance between the annulus (77) and the drive part (28) is smaller than the axial distance between the bearing edge (56) and the drive part (28), and the annulus extends radially outwards in the radially outer region and axially in a direction away from the drive part (28).

9. The air diverter valve according to claim 5, characterized in that the inner hollow body (52) comprises an insert (51) at least partially coated with elastomeric plastic (53), wherein the inner hollow body (52) can be lowered onto the valve seat (44) by the elastomeric plastic (53) and abuts against the drive part (28).

10. The air diverter valve according to claim 1 or 2, characterized in that the inflow element (68) is fixed to the drive part (28) by its bottom (70).

11. The air diverter valve according to claim 1 or 2, characterized in that the inflow element (68) comprises a radially expanding part (76) by means of which the inflow element (68) abuts against the radially constricted part (60) of the inner hollow body (52) at least in the open state.

12. The air diverter valve according to claim 5, characterized in that the cylinder (48), the inner hollow body (52) and the inflow element (68) are made of deep-drawn sheet metal parts.

13. The air diverter valve according to claim 1 or 2, characterized in that The actuator (10) is an electromagnet, and the drive member (28) is the armature of the electromagnet.

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