BYPASS VALVE

Description

[0001] The invention relates to a diverter valve with a flow housing having a flow channel between an inlet and an outlet, a valve seat formed between the inlet and the outlet, an actuator, an actuating member which can be moved translationally by means of the actuator, a control body which is fastened to the actuating member and which has a radially outer circumferentially closed jacket surface, at the axial end of which a circumferential support edge is formed which can be placed onto the valve seat and lifted off from the valve seat, wherein the control body has a radially inner axial inflow surface on the axial side facing away from the actuating member, and has a wall which extends at least radially inwards from the jacket surface and in which at least one opening is formed, via which an interior of the diverter valve is fluidically connected to the flow channel.

[0002] Bypass valves are used in a conventional manner to recirculate compressed fresh gas, possibly with recirculated exhaust gas, from the pressure side of a turbocharger compressor back to the suction side of the compressor. The connection between the pressure side and the suction side of the compressor via a bypass line is required for the transition from high load to overrun operation of the internal combustion engine, preventing high delivery of the turbocharger compressor against a closed throttle valve and the resulting pumping effect.

[0003] Diverter valves are often actuated electromagnetically, with the valve's control body being moved via the armature by the electromagnetic force. A diverter valve of this type is known, for example, from DE 10 2016 118 341 A1, which discloses a diverter valve according to the preamble of claim 1, WO 2019 121 305 A1, and WO 2019 121 532 A1. The valve has a pressure equalization opening on the control body connected to the armature. With appropriate design of the effective surfaces, this creates a force equilibrium with regard to the pneumatic forces acting on the control body. For actuation, only the force of a spring needs to be overcome, resulting in very short actuation times for the diverter valve. In this valve, the closure body is connected directly to the armature, and the interior of the valve is separated from the exterior by a membrane.However, the problem arises that with very small strokes from the closed position, the static pressure drops very quickly due to the resulting dynamic pressure, which causes a large force to act on the control body in the closing direction.

[0004] Furthermore, DE 10 2008 005 088 B3 discloses a diverter valve comprising a control body with a radially outer surface, from which an axial inflow surface extends radially inward at the end remote from the actuator. An opening is formed centrally on the control body for pressure equalization.

[0005] In addition, CN 204611049 U discloses a control body of a diverter valve having a radially outer surface, from the end of which facing the actuator extends a radially inwardly extending axial inflow surface in which openings for pressure equalization are formed.

[0006] In previous generations of diverter valves, such as those described in EP 1 762 712 B1, attempts were made to transfer this low static pressure generated during opening to the opposite side of the control body by positioning the openings directly at the narrow opening area. However, this requires relatively large spring forces to close and thus also relatively large forces to initiate the opening movement by the electromagnet, which must be designed accordingly.

[0007] The task therefore arises of providing a diverter valve with which, on the one hand, very fast actuating times can be achieved and, on the other hand, low electromagnetic actuating forces are required, whereby the installation space of the diverter valve and in particular the space for the electromagnet can be reduced and the diverter valve can thus be manufactured more cost-effectively.

[0008] This object is achieved by a diverter valve having the features of main claim 1.

[0009] The control body of the diverter valve according to the invention has a radially outer, circumferentially closed jacket surface, at the axial end of which a circumferential support edge is formed, which can be placed onto the valve seat and lifted off from the valve seat, wherein the support edge is understood to be a narrow annular surface that narrowly tapers towards the valve seat. The control body further has, on the axial side facing away from the actuating element, a radially inner axial inflow surface, which is at least indirectly connected to the jacket surface via an at least radially extending wall. At least one opening is formed in this wall, via which an interior of the diverter valve is fluidically connected to the flow channel, so that the same pressure is present below and above the control body, at least as long as the latter is not moved.A radially outer trailing edge of the axial inflow surface is offset in the axial direction from the support edge by a maximum distance such that a first vector from the radially outer trailing edge to the nearest point on the support edge forms an angle of no more than 15° with a plane spanned by the support edge. This means that there is only a slight axial offset between the trailing edge of the inflow surface and the support edge of the control body. This has the consequence that the air flow is directed approximately in the direction of the free gap between the valve seat and the support edge of the control body when the valve is first opened. Furthermore, the at least radially extending wall with the at least one opening is offset axially in the direction of the actuating element from the support edge and from the trailing edge.Due to the axial distance between the wall and the contact edge, the pressure difference in the closing direction during opening, which is created by the flow, only acts on the thin contact edge, resulting in only a very low closing force acting on the control body. By conducting the current into the gap and the small available contact surface for the resulting pressure, a uniform force curve is created during opening with low required opening forces. This allows the electromagnet to be designed smaller, yet still achieve fast opening and closing times.

[0010] The axial inflow surface is formed on an inflow element with a closed base facing the actuating element and an open axial end facing away from the actuating element, on which the radially outer trailing edge is formed. The inflow surface is thus formed by a roughly cup-shaped body that is easy to manufacture and can be used to facilitate the attachment of the control body to the actuating element by welding the base centrally to the actuating element.

[0011] Preferably, a tangent vector points to a point on the radially outer trailing edge in a region facing away from the actuating element, which axially adjoins the support edge. As a result, the flow is directed directly into the gap between the valve seat and the support edge during the initial opening process, thereby significantly reducing the force acting on the control body in the closing direction due to the air flow.

[0012] Furthermore, it is advantageous if the at least radially extending wall is offset so far in the direction of the actuating member that a second vector in the radially outward direction from the at least radially extending wall to the support edge encloses an angle of at least 20° with a plane spanned by the support edge. This has the result that the wall is offset so far back that the falling pressure in the gap cannot act directly on the wall surface, thereby reducing the force acting on the control body in the closing direction. In this context, "radially outward" simply means that the vector has a radial component that points away from the center axis of the diverter valve. Of course, however, there will also be an extension component of the vector in the axial direction. This applies to all vectors mentioned in this application, which by definition point radially outward.

[0013] Furthermore, it is preferred that the opening is offset so far in the direction of the actuating member that a third vector in the radially outward direction from the opening to the support edge encloses an angle of at least 30° with a plane spanned by the support edge, and that a fourth vector in the radially outward direction from the trailing edge to the opening encloses an angle of at least 30° with a plane spanned by the support edge. In this way, the force balance is maintained at the two axial ends of the openings even in the event of sudden changes in position and thus pressure on the surface facing the inlet, thereby achieving short actuating times and requiring low actuating forces.

[0014] Preferably, the circumferentially closed shell surface is formed by a cylindrical body and a radially outer region of an inner hollow body, which faces axially toward the valve seat and to which the cylindrical body is attached. The inner hollow body is motion-coupled to the actuating member and has the wall with the at least one opening and the support edge. This design facilitates the assembly of the control body.

[0015] In a further embodiment of the invention, the radially outer trailing edge is formed on a collar that extends radially outward and, if necessary, axially from the open axial end of the inflow element. This allows a correspondingly aligned trailing edge to be provided without additional components.

[0016] It is preferably possible for the collar to have a greater axial distance from the actuating element than the contact edge and to extend exclusively radially outward in the radially outer region. In this case, the flow would be directed radially outward and thus into the gap between the valve seat and the contact edge during the initial opening process.

[0017] In an alternative embodiment, the collar has a smaller axial distance from the actuating element than the support edge and extends radially outward in the radially outer region and axially in a direction away from the actuating element. In this case, too, the trailing edge points into the gap between the control body and the valve seat immediately after the initiation of the opening process. In both alternative embodiments, the closing force acting on the control body is reduced shortly after the initiation of the opening process compared to known embodiments.

[0018] Preferably, the inner hollow body has an insert that is at least partially coated with an elastomeric plastic. The inner hollow body, together with the plastic, can be lowered onto the valve seat and rests against the actuating element. This plastic coating on the contact edge ensures a tight valve seat, as slight unevenness can be compensated for by the elasticity. The plastic coating in the area where it contacts the actuating element ensures that the control body can be tilted slightly toward the actuating element, which also leads to improved sealing.

[0019] For this purpose, the inflow element is attached to the actuator via its base. The base can be attached to the actuator by simple laser welding.

[0020] To secure the entire control body, the inflow element has a radial extension, which, at least in the open state, rests against a radial constriction of the inner hollow body. The inner hollow body can be tilted slightly relative to the inflow element, which is attached to the actuator, and thus relative to the outer surface and the contact edge.

[0021] A particularly cost-effective production process is achieved when the cylindrical body, the inner hollow body and the inflow element are made as deep-drawn parts from sheet metal.

[0022] Preferably, the actuator is an electromagnet, and the actuating element is the electromagnet's armature. This enables short actuation times.

[0023] This creates a diverter valve that is highly durable and leak-proof. Most importantly, the size of the electromagnet and thus the manufacturing costs can be significantly reduced, as the forces that must be overcome during the opening process are reduced by the special outflow from the inflow element, which, on the one hand, optimally adjusts the flow direction and, on the other hand, reduces the contact surfaces available for a pressure difference.

[0024] An embodiment of a diverter valve according to the invention is shown in the figures and is described below.

[0025] The figure shows a side view of a diverter valve according to the invention in a sectional view.

[0026] The diverter valve shown in the figure consists of an actuator 10 designed as an electromagnet, in whose housing 12 a coil 14 is wound on a coil carrier 16. In the radially inner region of the coil carrier 16, a magnetizable core 18 is attached, the axial end of which projects beyond the coil carrier 16, wherein the core 18 is surrounded at this axial end by a return plate 20, which is connected to an iron casing 22 surrounding the coil 14. At the end of the coil carrier 16 opposite the core 18, there is another return plate 24, which is in contact with the iron casing 22 in the radially outer region and with a sliding bushing 26 in the radially inner region, which extends into the coil carrier 16. An armature acting as an actuating element 28 is mounted in the sliding bushing 26. When the coil 14 is energized, this armature is pulled by the electromagnetic force to the core 18 and into its recess 30.The coil 14 is supplied with power via contacts that lead to a plug 32.

[0027] A control body 34 is attached to the actuating member 28, by means of which a flow cross-section of a flow channel 38 formed in a flow housing 36, which connects an inlet 40 to an outlet 42, can be opened or closed by lowering the control body 34 onto or lifting it off a valve seat 44 surrounding the flow cross-section.

[0028] The control body 34 consists of a radially outer, circumferentially closed cylindrical surface 46, which is formed by a radially outer cylindrical body 48, which is made, for example, from sheet metal by deep drawing, and a radially outer region 50 of an inner hollow body 52, which region points axially towards the valve seat 44.

[0029] The inner hollow body 52 consists of an insert 51 produced from sheet metal by deep drawing and has a wall 54 which has at least one radial extension component facing inwards or extends radially inwards at least in sections. To form the inner hollow body 52, the insert 51 is overmolded with an elastomeric plastic 53 which forms a support edge 56 in the radially outer region 50 facing axially towards the valve seat 44, with which support edge 56 the control body 34 rests on the valve seat 44 when the diverter valve is in the closed state. The effective diameter for resting on the valve seat 44 essentially corresponds to the diameter of the cylindrical outer surface 46, thereby establishing a force equilibrium of the pneumatic forces acting on the control body 34 in the static state.

[0030] The wall 54 of the inner hollow body 52 is cylindrical in a first section 58. This cylindrical section 58 is adjoined by a radial constriction 60, from whose inner diameter a further cylindrical section 62 extends toward the actuating member 28, which correspondingly has a smaller diameter than the first cylindrical section 58. At its axial end, the cylindrical section 62 is bent slightly inward. In the region of the radial constriction 60, several axial bores are formed, which, as openings 64, enable pressure equalization between the underside and the top of the control body 34.

[0031] The cylindrical sections 58, 62 and the constriction 60, with the exception of the openings 64, are overmolded with the elastomeric plastic 53, which projects axially in the direction of the actuating member 28 beyond the cylindrical section 62.

[0032] The control body 34 further comprises a radially inner axial inflow surface 66, which in the present embodiment is formed on an inflow element 68, which serves to fasten the control body 34 to the actuating member 28. The inflow element 68 can also be produced by deep drawing and is essentially pot-shaped, with a base 70 arranged in a central circular recess 72 at the axial end of the actuating member 28 and secured at this point by welding. A cylindrical section 74 adjoining the base 70 extends to the end of the elastomer 53 on the inner hollow body 52 facing away from the actuating member 28 and has an outer diameter that is smaller than the inner diameter of the elastomeric plastic 53.Adjoining this cylindrical section 74 on the axial side opposite the base 70 is a radial extension 76 in the form of a ring, which projects radially beyond the elastomer 53 and whose outer diameter is thus larger than the inner diameter of the constriction 60 of the inner hollow body 52. ​​The distance of the radial extension 76 from the base 70 of the inflow element 68 is selected such that a small gap remains between the elastomer 53 surrounding the constriction 60 of the inner hollow body 52, when the hollow body 52 rests against the actuating member 28, and the extension 76 of the inflow element 68, so that the outer surface 46 can be tilted slightly towards the inflow element 68 and thus also towards the actuating member 28. In this way, a cardanic attachment of the control body 34 to the actuating member 28 is realized. From the radially outer end of the radial extension 76, the inflow element 68 extends axially to just before the support edge 56.An end of the inflow element 68 pointing away from the base 70 is designed as a collar 77 that extends slightly axially and radially. Its radially outer end forms an annular trailing edge 78, through which a flow is deflected onto a radially inner axial inflow surface 66 of the inflow element 68 in the direction of the outlet 42. The radially inner axial inflow surface 66 is formed by the sections of the inflow element 68 that point axially toward the inlet 40 and extend substantially radially. More precisely, a tangent vector 82 to the trailing edge 78, i.e., a tangent to the surface of the collar 77 that is directed toward the inlet 40 in the radially outer region, points into a region that is slightly further away from the actuator 10 than the support edge 56. Thus, when the valve is slightly open, this vector points into a gap between the valve seat 44 and the support edge 56.

[0033] In addition to this alignment of the trailing edge 78 to the support edge 56 and the associated flow line, their arrangement relative to one another is also important. Thus, the trailing edge 78 should be axially offset from the support edge 56 only to such an extent that a first vector 84, which begins at the trailing edge 78 and is directed radially outward toward the support edge 56, forms an angle of a maximum of 15° with a plane 86 spanned by the support edge 56, regardless of the direction in which this angle is measured. In the present case, the trailing edge 78 is slightly offset from the actuating element 28 compared to the support edge 56, resulting in an angle of approximately 8°.

[0034] Furthermore, the arrangement of the wall 54 and the openings 64 relative to the support edge 56 and the trailing edge 78 has a significant influence. Thus, a second vector 88, which extends radially outward from any point on the wall 54 toward the support edge 56, should form an angle of at least 20° with the plane 86 spanned by the support edge 56. In the exemplary embodiment, this angle is between 40° and 70°.

[0035] In addition, an angle between a third vector 90, which extends radially outward from one of the openings 64 to the support edge 56, and the plane 86 should be at least 30°. In the present embodiment, this angle is approximately 60°. An angle between a fourth vector 92, which extends radially outward from the trailing edge to one of the openings 64, and the plane 86 should also be at least 30°. This angle is approximately 66° in the present embodiment.

[0036] Due to this arrangement of the trailing edge 78, the support edge 56, the wall 54, and the openings 64 relative to one another, there is almost no surface area for a decreasing pressure in the gap between the valve seat 44 and the control body 34 due to the flow when opening. The pressure difference that would otherwise arise due to the flow is also reduced by the targeted introduction of the flow into the gap.

[0037] Furthermore, an interior space 94 is formed in the housing 12 of the diverter valve, into which the control body 34 can be immersed when the valve is actuated. This interior space 94 is radially delimited by a housing wall 96, to the end of which facing away from the actuator 10, an annular plate 98 is attached, the inner diameter of which is slightly larger than the outer diameter of the outer circumferential surface 46. A V-shaped seal 100 with two legs rests on this plate 98, the first of which bears against the circumferentially closed circumferential surface 46, and the second leg of which bears against the radially delimiting housing wall 96, so that the interior space 94, when the valve is closed, is connected to the inlet 40 below exclusively via the openings 64.In order to also supply the central recess 30 between the actuating member 28 and the core 18 with a corresponding pressure and thus create a pressure-balanced valve, one or more grooves are arranged on the outer circumference of the actuating member 28.

[0038] Furthermore, a spring 102 is arranged inside the outer surface 46, which rests axially against the wall 54, and whose opposite axial end rests against the housing 12 of the actuator 10, whereby, when the coil 14 is not energized, the control body 34 is placed in its state resting on the valve seat 44. In this static state, a force equilibrium exists, so that the spring 102 can be designed such that the diverter valve remains in the closed state even when pressure pulsations occur.

[0039] To open, the actuator 10 is energized, whereby only the force of the spring 102 must be overcome. As soon as a gap between the valve seat 44 and the support edge 56 is opened, a flow is created through this gap. The influence of the resulting static pressure fluctuations is largely avoided because the wall 54 is sufficiently far away from the valve seat 44 and only the thin support edge 56 can serve as an attack surface for the pressure difference. Pressure equalization can also take place in the interior 94 because the flow line by means of the inflow element 68 prevents any flow acting directly on the openings 64, whereby rapid static pressure equalization can take place immediately upon opening, which would otherwise be inhibited and thus lead to an additional force acting in the closing direction.

[0040] Accordingly, very fast positioning times can be achieved with a very small and therefore cost-effective electromagnet.

[0041] It should be clear that the present invention is not limited to the described embodiment. A different actuator may also be used, or the outer surface and the at least radially extending wall may be manufactured as a single piece. The inflow element may also be manufactured as a single piece with the rest of the control body or have a different design, since the orientation of the trailing edge is particularly functionally relevant. The elastomer may also be omitted, or it may be used only in the support area.

Claims

1. Blow-off valve comprising 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), an actuating member (28) movable in translation by means of the actuator (10), and a control body (34) fastened to the actuating member (28), which control body has a radially outer circumferentially closed lateral surface (46), at the axial end of which a circumferential bearing edge (56) is formed, which can be placed onto the valve seat (44) and can be raised from the valve seat (44), wherein the control body (34) has a radially inner axial inflow surface (66) on the axial side pointing away from the actuating member (28) and has an at least radially extending wall (54), via which the radially inner axial inflow surface (66) is at least indirectly connected to the lateral surface (46), which wall extends at least radially inward from the lateral surface (46), and in which wall at least one opening (64) is formed, via which an interior space (94) of the blow-off valve is fluidically connected to the flow channel (38), wherein the axial inflow surface (66) is formed on an inflow element (68) with a closed base (70) pointing towards the actuating member (28) and an open axial end pointing away from the actuating member (28), on which open axial end a radially outer annular outflow edge (78) of the axial inflow surface (66) is formed, characterized in that the outflow edge (78) is offset in the axial direction with respect to the bearing edge (56) at most to such an extent that a first vector (84) radially outward from the outflow edge (78) to the nearest point of the bearing edge (56) encloses at most an angle of 15° with respect to a plane (86) which is spanned by the bearing edge (56), and the at least radially extending wall (54) with the at least one opening (64) is offset axially in the direction of the actuating member (28) with respect to the bearing edge (56) and with respect to the outflow edge (78).

2. Blow-off valve according to Claim 1, characterized in that a tangent vector (82) at a point of the radially outer outflow edge (78) points into a region which faces away from the actuating member (28) and which axially directly adjoins the bearing edge (56).

3. Blow-off valve according to Claim 1 or 2, characterized in that the at least radially extending wall (54) is offset in the direction of the actuating member (28) to such an extent that a second vector (88) in the radial direction outward from the at least radially extending wall (54) to the bearing edge (56) encloses at least an angle of 20° with respect to the plane (86) which is spanned by the bearing edge (56).

4. Blow-off valve according to one of the preceding claims, characterized in that the at least one opening (64) is offset in the direction of the actuating member (28) to such an extent that a third vector (90) in the radial direction outward from the at least one opening (64) to the bearing edge (56) encloses at least an angle of 30° with respect to the plane (86) which is spanned by the bearing edge (56), and a fourth vector (92) in the radial direction outward from the outflow edge (78) to the opening (64) encloses at least an angle of 30° with respect to the plane (86) which is spanned by the bearing edge (56).

5. Blow-off valve according to one of the preceding claims, characterized in that the circumferentially closed lateral surface (46) is formed by a cylindrical body (48) and a radially outer region (50), which points axially towards the valve seat (44), of an inner hollow body (52), to which the cylindrical body (48) is fastened, wherein the inner hollow body (52) is coupled in terms of movement to the actuating member (28) and has the wall (54) with the at least one opening (64) and the bearing edge (56).

6. Blow-off valve according to one of the preceding claims, characterized in that the radially outer outflow edge (78) is formed on a collar (77) which extends radially outward and optionally axially from the open axial end of the inflow element (68).

7. Blow-off valve according to Claim 6, characterized in that the collar (77) is at a greater axial distance from the actuating member (28) than the bearing edge (56) and extends exclusively radially in the radially outer region.

8. Blow-off valve according to Claim 6, characterized in that the collar (77) is at a smaller axial distance from the actuating member (28) than the bearing edge (56) and extends radially outward in the radially outer region and extends axially in a direction pointing away from the actuating member (28).

9. Blow-off valve according to one of claims 5 to 8, characterized in that the inner hollow body (52) has an insert part (51) which is at least partially coated with an elastomeric plastic (53), wherein the inner hollow body (52) with the elastomeric plastic (53) can be lowered onto the valve seat (44) and bears against the actuating member (28).

10. Blow-off valve according to one of the preceding claims, characterized in that the inflow element (68) is fastened with the base (70) to the actuating member (28).

11. Blow-off valve according to one of the preceding claims, characterized in that the inflow element (68) has a radial widening (76) with which the inflow element (68) bears against a radial constriction (60) of the inner hollow body (52) at least in the open state.

12. Blow-off valve according to one of the preceding claims, characterized in that the cylindrical body (48), the inner hollow body (52) and the inflow element (68) are produced as deep-drawn parts from sheet metal.

13. Blow-off valve according to one of the preceding claims, characterized in that the actuator (10) is an electromagnet and the actuating element (28) is the armature of the electromagnet.