Adjustable damping valve device with an electromagnetic actuator

Abstract

Adjustable damping valve device comprising an actuator with a solenoid coil and an axially movable armature, wherein a groove-rib profile connection is functionally provided between the armature and a component conducting a magnetic flux of the solenoid coil, which engages when the actuator is actuated, wherein the ribs have at least partially different immersion depths in the corresponding grooves when the actuator is actuated.

Description

[0001] The invention relates to an adjustable damping valve device according to the preamble of claim 1.

[0002] In an adjustable damping valve assembly with an electromagnetic actuator, a fundamental problem lies in applying a sufficiently large actuating force to the valve armature. The actuating force depends, among other things, on the number of turns in the actuator's solenoid coil. However, a high number of turns necessitates a correspondingly larger solenoid coil. In a damping valve assembly mounted on the axially movable piston rod of a vibration damper, the axial length of the solenoid coil effectively represents a loss of stroke for the vibration damper. If the damping valve assembly is located externally on the vibration damper, it engages with the wheel's suspension space. Consequently, a stress field exists between the installation space for the electromagnetic actuator, which is part of the damping valve assembly, and the installation space for the vibration damper on which the damping valve assembly is mounted.

[0003] From DE 41 23 141 C1, an adjustable damping valve device with an electromagnetic actuator is known, comprising a solenoid coil and an armature. The armature and a return element have a groove-ring profile, such that when the solenoid coil is energized, several parallel magnetic flux transition areas are active simultaneously to maximize the actuating force of the actuator.

[0004] The problem is solved by ensuring that, when the actuator is activated, the webs have at least partially different immersion depths in the corresponding grooves.

[0005] The increasing overlap ratio within the groove-web profile connection, which increases with the axial stroke of the armature, leads to a significant increase in force with comparable current flow to the magnet coil. The grooves are preferably designed as annular grooves and the webs as annular webs.

[0006] In one embodiment, the web on the largest pitch circle has a greater axial height than the web on an adjacent smaller pitch circle. This provides a larger transmission cross-section at the beginning of the anchor movement, which then increases moderately due to the subsequent engagement of the axially shorter web.

[0007] However, it is also possible to design the web on a larger pitch circle to have a smaller axial height than the web on an adjacent smaller pitch circle. In this case, relative to a larger anchor stroke, a comparatively larger transmission cross-section becomes effective.

[0008] Provided that the available installation space allows, it can also be advantageous if the groove-web-profile connection is arranged on at least three different pitch circle diameters, with the inner and outer webs having a smaller axial height than the at least one middle web.

[0009] In a further advantageous embodiment of the invention, at least one of the webs has an inclined end face pointing towards the corresponding groove. The inclined end face provides an advantageous increase in the transmission cross-section and a centering function between the armature and the conductive component.

[0010] Preferably, all end faces of the webs are inclined in the same direction, as this component geometry is particularly easy to manufacture.

[0011] Functionally, it is advantageous if the end face of the axially lower web rises in the direction of an adjacent axially higher web.

[0012] With regard to optimal magnetic flux transfer between the conductive component and the armature, an axially higher web dips into an axially deeper groove than an axially lower web.

[0013] Preferably, the base surface of the groove is inclined corresponding to the end face of the immersing web. This ensures optimal transfer of the magnetic flux from the valve armature to the conductive component.

[0014] Preferably, a vibration damper is operatively connected to the adjustable damping valve assembly. Due to the higher adjustment force of the actuator, the damping force characteristics can be adjusted quickly and with reduced energy input compared to the prior art.

[0015] The following description of the figures will be used to explain the invention in more detail.

[0016] It shows: Fig. 1 Installation situation of the damping valve device on a vibration damper Fig. 2 Sectional view through the damping valve assembly Fig. 3 Detail section of the Fig. 2 Fig. 4 and 5 alternative variants to Fig. 2

[0017] In Fig. A vibration damper comprises a cylinder 1 in which a piston rod 3 is axially movable. A guide and sealing unit 7 extends the piston rod 3 from the upper end of the cylinder. Inside the cylinder 1, a piston assembly 9 with a piston valve assembly 11 is attached to the piston rod 3. The lower end of the cylinder 1 is closed by a base plate 13 with a base valve assembly 15. The cylinder 1 is enclosed by a reservoir tube 17. The reservoir tube 17 and an intermediate tube 5 form an annular space 19, which constitutes a compensating chamber. The space inside the cylinder 1 is divided by the piston assembly 9 into a first working chamber 21a and a second working chamber 21b. The working chambers 21a and 21b are filled with damping fluid. The compensating chamber 19 is filled with fluid up to the level 19a and with gas above that level.Within the compensation chamber 19, a first line section, namely a high-pressure section 23, is formed, which is connected to the second working chamber 21b via a bore 25 of the cylinder 1. An adjustable damping valve assembly 27, mounted laterally on the reservoir tube 17, is connected to this high-pressure section. From this, a second line section, namely a low-pressure section 29 (not shown), leads into the compensation chamber 19.

[0018] When the piston rod 3 extends upwards from the cylinder 1, the upper working chamber 21b shrinks. An overpressure builds up in the upper working chamber 21b, which can only be released into the lower working chamber 21a via the piston valve assembly 11 as long as the adjustable damping valve 27 is closed. When the adjustable damping valve assembly 27 is open, fluid simultaneously flows from the upper working chamber 21b through the high-pressure section 23 and the adjustable damping valve assembly 27 into the compensation chamber 19. The damping characteristic of the vibration damper during the extension of the piston rod 3 therefore depends on whether the adjustable damping valve assembly 27 is more or less open or closed.

[0019] When the piston rod 3 retracts into the cylinder 1, an overpressure builds up in the lower working chamber 21a. Fluid can flow from the lower working chamber 21a upwards through the piston valve assembly 11 into the upper working chamber 21b. The fluid displaced by the increasing piston rod volume within the cylinder 1 is expelled through the bottom valve assembly 15 into the compensation chamber 19. Since the flow resistance of the piston valve assembly 11 is lower than that of the bottom valve assembly 15, an increasing pressure also occurs in the upper working chamber 21b. With the damping valve assembly 27 open, this increasing pressure can again flow through the high-pressure section 23 into the compensation chamber 19.This means that with the damping valve assembly 27 open, the vibration damper has a softer characteristic when retracting if the adjustable damping valve assembly 27 is open, and a firmer characteristic when the damping valve assembly 27 is closed, just as when the piston rod is extending. It should be noted that the flow direction through the high-pressure section 23 of the bypass is always the same, regardless of whether the piston rod is retracting or extending.

[0020] The adjustable damping valve assembly 27 is located in the Fig. Figure 2 shows a cross-sectional view. In principle, the invention can also be used with a damping valve device 27 on the piston rod 3.

[0021] The damping valve assembly 27 comprises an actuator 31 with a solenoid coil 33 for controlling an armature 35, which is at least indirectly connected to a pre-stage valve 37, which in turn determines a closing force on a main stage valve 39. The main stage valve 39 has a main stage valve body 41, the rear side of which forms a valve seat surface 43 for a pre-stage valve body 45.

[0022] Furthermore, the damping valve assembly 27 has an emergency operating function based on the position of an emergency operating body 47, which is biased by a spring 48 in the direction of the pre-stage valve body 45.

[0023] The armature 35 is slidably mounted in a sleeve-shaped return body 49, the return body 49 having a bottom-side pole disk 51 that is fixedly arranged relative to a valve housing 53. In this embodiment, the valve armature 35 is mounted in the pole disk 51 and in a cover area 61 of the return body 49 via a central armature rod 55 with intermediate bearing sleeves 57; 59.

[0024] The emergency operating body 47 switches between an emergency operating position and a normal operating position depending on the power supply to the magnetic coil 33, whereby the emergency operating body 47 is switched by the force of the magnetic flux of the magnetic coil 33 through the backstop body 49 and the pole disk 51.

[0025] A magnetic flux resistor is arranged between the pole disk 51 and the valve housing 53, preventing a magnetic flux short circuit with respect to the pole disk 51. The magnetic flux resistor ensures that the magnetic flux is conducted from the pole disk 51 to the emergency operating element 47, thereby achieving the greatest possible tensile force on the emergency operating element 47 relative to the set current for the solenoid coil 35. This tensile force holds the emergency operating element 47 in the normal operating position against the force of the spring 48 when a threshold current for the solenoid coil is exceeded. In the emergency operating position, the emergency operating element 47 rests against the rear of the pre-stage valve body 45. The spring 48 then indirectly transmits a closing force to the pre-stage valve body 45.In the normal operating position of the emergency operating element 47, there is a gap between the emergency operating element 47 and the pre-stage valve body 45, irrespective of the operating position of the pre-stage valve body 45. It can be provided that the emergency operating element 47 rests against the pole disk 51 in the normal operating position.

[0026] How to Fig. 2 can be seen, the magnetic flux resistance is formed by a reduction in wall thickness 63 by an increase in the inner diameter of the return body 49.

[0027] The back end body 49 has a multi-stage internal profile, in which the wall thickness reduction 63 is formed by an internal shoulder 65 of the back end body 49, on which the pole disk 51 is also axially supported.

[0028] The reduction in wall thickness 63 of the return body 49 is axially limited to a minimal length, namely essentially to the axial extent of a contact surface 67 of the pole disk 51 with the return body 49. The contact surface 67 also serves as a pressing surface for a force-fit connection to the valve housing 53. The reduction in wall thickness 63 also promotes the radial expansion capability of the return body 49 to accommodate the pole disk 51.

[0029] The valve housing 53 has an axial support surface 69 for the solenoid coil 33, with the wall thickness reduction 63 extending axially from this support surface 69 towards the cover area 61 of the return body 49. Thus, the area with the wall thickness reduction 63 is located entirely within an internal area bounded by the solenoid coil 33. An area of ​​the valve housing 53 located below the solenoid coil 33 can be used and optimized for other functions.

[0030] In principle, the return element 49 and the valve housing 53 could be manufactured as two parts and then joined together. Preferably, the return element 49 and the valve housing 53 are manufactured seamlessly as a single piece. This one-piece construction avoids manufacturing tolerances that would result from a two-part design.

[0031] Optionally, the return body 49 has a second magnetic flux resistance 71 within the sleeve-shaped section, which is connected in parallel to a magnetic flux path from the return body 49 to the valve armature 35. The second magnetic flux resistance 71 is also formed by a reduction in wall thickness, but this reduction is formed by an outer circumferential groove. Starting from the radially deepest region of the groove, i.e., the thinnest wall thickness, the wall thickness of the return body 49 increases towards the pole disk 51. The pole disk 51 also rests directly against the shoulder of the return body 49. Consequently, the area from the second reduction in wall thickness 71 to the top surface of the pole disk 51 forms a step for the armature 35.

[0032] The immersion step area is optimized such that a groove-ribbed profile connection 73 functionally exists between the armature 35 and a component conducting a magnetic flux from the magnet coil 33, in this case the pole disk 51. This connection engages when the actuator 31 is actuated. When the actuator 31 is actuated, the ribs 75 have at least partially different immersion depths in the corresponding grooves 77. The ribs 75 are designed as closed ring ribs on the top side of the pole disk 51 facing the armature 35. Accordingly, the underside of the armature 35 has the concentrically arranged grooves 77.

[0033] In the execution according Fig. 2. The web 75 on a largest pitch circle 79 has a greater axial height than the web 75 on an adjacent smaller pitch circle 81. Furthermore, it can be seen from the Fig. 2 can be seen that at least one of the webs 75 has an inclined end face 83 pointing towards the corresponding groove 77. In this embodiment, all end faces 83 of the webs 75 are inclined in the same direction, namely towards a central axis 85 of the pole disk 51. In the Fig. Figure 3 shows an enlarged view of this area of ​​the damping valve assembly 27.

[0034] In principle, it is intended that an axially higher web 75 of the pole disk 51 engages in an axially deeper groove 77 of the armature than a radially adjacent axially lower web 75. Optionally, a groove base surface 87 of the groove 77 is inclined corresponding to the end face 83 of the engaging web 75. Consequently, it is possible that all end faces 83 of the webs 75 have the same axial distance to the respective groove base surface 87.

[0035] The design of the damping valve device 27 according to Fig. Figure 4 shows, among other things, the pole disk 51 as the component conducting the magnetic flux, in which the web 75 on the largest pitch circle 79 has a smaller axial height than the web 75 on the radially inner adjacent smaller pitch circle 81. The further design with regard to the end faces 83, the groove depth and the orientation of the groove base surface 87 corresponds to the description of the Fig. 2 and Fig. 3. While during execution according Fig. 2. First, the larger diameter web 75 has a larger cross-sectional area for conducting the magnetic flux, and the smaller diameter radial inner web 75 offers a smaller increase in cross-sectional area when the smaller web enters the annular groove 77. This process begins in the Fig. 4. The magnetic flux transfer occurs on the smaller pitch circle 81 with a smaller conductive cross-section, but a greater increase in cross-sectional area as the armature 35 approaches the pole disk 51 further. The increase in the actuator's actuating force is proportional to the increase in cross-sectional area at the magnetic flux transfer point. Consequently, in the Fig. 2 a higher initial actuation force with a smaller slope gradient and in the Fig. 4. A lower initial actuation force with a larger gradient is available.

[0036] Both in the damping valve device after Fig. 2 as also in the Fig. 4 the design principle is realized after the end face 83 of the axially lower web 75 rises in the direction of an adjacent axially higher web 75.

[0037] With the design of the polar disc according Fig. Figure 5 is intended to demonstrate by way of example that further embodiments of the web profile are also possible. In particular, if the surface area of ​​the component conducting the magnetic flux is sufficiently large, the web-profile connection 73 can be arranged on at least three different pitch circle diameters 79; 81; 89, wherein the inner and outer webs 75 have a smaller axial height than the at least one middle web 75. The illustration of the grooves 77 in the armature 35 was referred to in the Fig. 5 is omitted. But here too, the rules already described for the design of the grooves 77 would apply.

[0038] When the solenoid coil 33 is energized, a closed magnetic flux path exists around the solenoid coil 33. With a valve housing cover 91, see below. Fig.2. A component that conducts magnetic flux very well is present, which has direct contact with the return element 49 in the area of ​​a through-opening 93 in a base. The magnetic flux enters the return element 49 at this point. Further along, up to the second wall thickness reduction 71, the return element 47 has a wall cross-section optimized for radial transmission of the magnetic flux to the armature 35. Due to the second magnetic flux resistance 71, the magnetic flux passes through the armature 35 and enters the armature 35 via the groove-web profile connection 73. With increasing current and as the armature 35 approaches the pole disk 51, there is a greater axial overlap between the webs and the grooves, which increases the actuating force of the actuator 31. Reference sign 1 cylinder 3 Piston rod 5 Intermediate pipe 7 Guide and sealing unit 9 piston unit 11 Piston valve arrangement 13 Base plate 15 Bottom valve arrangement 17 Container pipe 19 Ring space 21a / b Chamber of Labour 23 High-pressure section 25 bore 27 Damping valve device 29 Low-pressure section 31 Actuator 33 Magnetic coil 35 Valve anchors 37 Pre-stage valve 39 Main stage valve 41 Main stage valve bodies 43 Valve seat surface 45 Pre-stage valve bodies 47 emergency power units 48 springs 49 Return body 51 Polarizing disc 53 Valve housings 55 Anchor rod 57 Bearing sleeve 59 Bearing sleeve 61 Cover area 63 Wall thickness reduction 65 paragraph 67 Contact area 69 support surface 71 second magnetic flux resistance 73 Groove-web profile connection 75 Bridge 77 Nut 79 large partial circle 81 small partial circle 83 Front surface of the bridge 85 Central axis of the pole disk 87 Groove base area 89 Middle subcircle 91 Valve housing cover 93 Passage opening QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 41 23 141 C1

[0003]

Claims

Adjustable damping valve device (27) comprising an actuator (31) with a solenoid coil (33) and an axially movable armature (35), wherein a groove-rib profile connection (73) is functionally provided between the armature (35) and a component (51) conducting a magnetic flux of the solenoid coil (33), which engages when the actuator (31) is actuated, characterized in that the ribs (75) have at least partially different immersion depths in the corresponding grooves (77) when the actuator (31) is actuated. Adjustable damping valve device (27) according to claim 1, characterized in that the web (75) on a largest pitch circle (79) has a greater axial height than the web (75) on an adjacent smaller pitch circle (81). Adjustable damping valve device (27) according to claim 1, characterized in that the web (75) on a largest pitch circle (79) has a smaller axial height than the web (75) on an adjacent smaller pitch circle (81). Adjustable damping valve device (27) according to claim 1, characterized in that the groove-web profile (73) is arranged on at least three different pitch circle diameters (79; 81; 89), wherein the inner and outer webs (77) have a smaller axial height than the at least one middle web (77). Adjustable damping valve device (27) according to one of claims 1 to 4, characterized in that at least one of the webs (75) has an end face (83) inclined in the direction of the corresponding groove (77). Adjustable damping valve device (27) according to claim 5, characterized in that all end faces (83) of the webs (75) are inclined in the same direction. Adjustable damping valve device (27) according to claim 6, characterized in that the end face (83) of the axially lower web (75) rises in the direction of an adjacent axially higher web (75). Adjustable damping valve device (27) according to one of claims 1 to 7, characterized in that an axially higher web (75) dips into an axially deeper groove (77) than an axially lower web (75). Adjustable damping valve device (27) according to one of claims 1 to 8, characterized in that a groove base surface (87) of the groove (77) is inclined corresponding to the end surface (83) of the immersing web (75). Vibration damper, characterized in that the vibration damper is operatively connected to an adjustable damping valve device (27) according to one of claims 1 to 9.

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