Adjustable hydraulic vibration damper

• US 5,558,189 A
• Filed: 07/26/1995
• Issued: 09/24/1996
• Est. Priority Date: 07/26/1994
• Status: Expired due to Fees

• Current Assignee: Fichtel & Sachs AG
• Original Assignee: Fichtel & Sachs AG
• Inventors: Beck, Hubert
• Primary Examiner(s): Oberleitner, Robert J.
• Assistant Examiner(s): Schwartz, Chris
• Application Number:
  US08/507,701
• Time in Patent Office: 426 Days
• Field of Search: 188/229, 188/315-317, 188/318, 188/312, 188/322.13, 188/322.15, 188/322.22, 280/707, 280/714
• US Class Current: 188/266.6
• CPC Class Codes: F16F 2230/0052 Physically guiding or influencing
• CPC Class Codes: F16F 9/465 using servo control, the servo pressure being created by the flow of damping fluid, e.g. controlling pressure in a chamber downstream of a pilot passage self-adjustment of damping F16F9/50

Abstract

A hydraulic, adjustable vibration damper with a piston fastened to a piston rod, which piston divides a working cylinder into two working chambers filled with damping fluid, whereby at least partly to control the damping force there is a pilot-controlled, electromagnetically actuated damping valve. In this valve, a valve body and a pilot control element each apply pressure to a valve seat, and at least the valve body is mounted in a guide so that it can be displaced axially. The valve body consists of at least two parts, whereby one part is held in the axial guide and is connected to the second part so that the second part is located running in an additional axial guide, so that it can be displaced radially with respect to the first part. Whereby the valve seat of the valve body may be disposed adjacent either the first part of the valve body or the second part of the valve body.

Claims

1. A vibration damper comprising:

a cylinder defining a chamber therein, said cylinder containing a damping fluid;

said cylinder having a longitudinal axis;

a piston rod sealingly projecting into said cylinder and being axially displaceable with respect to said cylinder;

a piston being attached to said piston rod, said piston being slidably disposed within said cylinder to sealingly divide said chamber into first and second chambers;

an outer tube disposed about said chamber, said piston and said piston rod;

means for permitting fluid communication between said first and second chambers;

said means for permitting fluid communication comprising electromagnetic damping valve means mounted at said outer tube;

said electromagnetic damping valve means comprising;

a valve arrangement, said valve arrangement having means for adjusting fluid communication between said first and second chambers;

a damping valve for adjusting the flow of the damping fluid between said first working chamber and said second working chamber;

said valve having a longitudinal axis about which said valve extends, said longitudinal axis of said valve extending essentially radially away from said longitudinal axis of said shock absorber cylinder;

said valve comprising;

a pilot valve;

said pilot valve comprising a pilot control element;

a valve body;

a valve seat;

said valve seat comprising a valving surface;

said valve body being disposed to rest against and close against said valve seat and open away from said valve seat, and thus permitting flow of said damping fluid across said valve seat;

said valving surface defining a planar area in which said valving surface is disposed;

said planar area being disposed substantially transverse to said longitudinal axis of said valve;

said valve seat being disposed to control a major flow of fluid through said valve;

said valve body comprising a first part and a second part;

said first part being movable with respect to said second part;

said first part having a first end portion and a second end portion;

said second end portion being opposite said first end portion;

said first end portion and said second end portion being disposed along said longitudinal axis of said valve;

said first end portion extending at least to said planar area defined by said valving surface;

said first end portion having a portion extending towards said valve seat;

said first end portion and said second end portion being rigidly connected to one another to prevent separation of said first end portion away from said second end portion;

said first valve body part being mounted in a first axial guide;

said second part being operatively connected to said first part such that said second part can be displaced radially within said valve with respect to the longitudinal axis of said valve;

said second part having a first extreme end and a second extreme end;

said second extreme end being opposite said first extreme end;

said first extreme end and said second extreme end being disposed along said longitudinal axis of said valve;

said first end portion of said first part extending beyond said first extreme end of said second part;

said second end portion of said first part extending beyond said second extreme end of said second part;

said second end portion of said first part being disposed adjacent said pilot control element;

said pilot control element being disposed to rest against and close against said second end portion of said first part and to open away from said second end portion of said first part, thus permitting flow of said damping fluid through said pilot valve;

said pilot control element being disposed to control a minor flow of fluid through said valve; and

said minor flow of fluid being substantially smaller than said major flow of fluid.

2. The vibration damper according to claim 1, wherein:

said first axial guide is disposed adjacent said second end portion of said first valve body part;

said first axial guide is disposed concentrically about said longitudinal axis of said valve;

said first axial guide extends a substantial distance along said longitudinal axis of said valve; and

said first axial guide is at a first radial distance from said longitudinal axis of said valve.

3. The vibration damper according to claim 2, wherein said first end portion of said first part comprises a first piece and a second piece;

and

said first piece and said second piece are rigidly connected to one another.

4. The vibration damper according to claim 3, wherein:

said second axial guide is disposed between said first axial guide and said first end portion of said first valve body part;

said second axial guide is disposed concentrically about said longitudinal axis of said valve;

said second axial guide is disposed at a second radial distance from said longitudinal axis of said valve;

said second radial distance is substantially greater than said first radial distance;

said first axial guide has a first axial length defined along said first valve body part;

said second axial guide has a second axial length defined along said second valve body part;

said first axial length is substantially greater than said second axial length;

said first valve body part has a first radial width defined transverse to said longitudinal axis of said valve;

said first radial width is substantially equal to said first radial distance;

said second valve body part has a second radial width defined transverse to said longitudinal axis of said valve;

said second radial width is substantially equal to said second radial distance; and

said first extreme end of said second valve body part is in contact with said portion extending toward said valve seat of said first end portion of said first valve body part.

5. The vibration damper according to claim 4, wherein said second part of said valve body is disposed so as to engage and disengage with said valve seat.

6. The vibration damper as claimed in claim 4, wherein said first part of said valve body is disposed so as to engage and disengage with said valve seat.

7. The vibration damper according to claim 6, wherein said valve further comprises:

a spring;

said spring is disposed between said first part and said second part of said valve body; and

said spring being disposed to prestress said first part and said second part axially toward one another.

8. The vibration damper according to claim 7, wherein said valve seat of said valve body comprises one of:

a planar surface; and

a conical surface.

9. The vibration damper according to claim 8, wherein said first end portion of said first valve body part comprises passage means for permitting the entry of damping fluid into said first valve body part.

10. The vibration damper according to claim 9, wherein:

at least a portion of said pilot control chamber is disposed in said first valve body part;

said pilot control chamber extends from said first end portion of said first valve body part to said second end portion of said first valve body part;

said pilot control chamber comprises orifices disposed in said first valve body part;

said pilot control chamber comprises sub-chambers disposed adjacent said second valve body part; and

said pilot control chamber extends to said pilot control element.

11. The vibration damper according to claim 10, wherein said first piece of said first end portion of said first valve body part extends along said longitudinal axis of said valve;

said second piece of said first end portion of said first valve body part comprises said portion of said first end portion of said first part extending toward said valve seat; and

said second piece comprises a circular plate;

said valve body comprises a surface area portion for engaging and disengaging with said valve seat; and

said surface area portion comprises one of;

a planar surface; and

a conical surface.

12. The vibration damper according to claim 11, wherein:

said vibration damper further comprises;

another tube;

said another tube being disposed concentrically about said longitudinal axis of said vibration damper;

said another tube being disposed between said cylinder and said outer tube;

a compensating chamber;

said compensating chamber being substantially disposed between said cylinder and said outer tube;

said compensating chamber comprising a fluid path;

said fluid path being substantially disposed between said another tube and said cylinder;

said valve further comprises;

at least a part of said first valve body part being disposed substantially concentrically about said longitudinal axis of said valve to form at least a part of said pilot control chamber;

said pilot control element being a substantially conical-shape structure;

said conical shape structure having a first part and a second part;

said first part comprises a substantially narrow end of said conical-shape structure and said second part comprises a substantially broader end of said conical-shape structure;

wherein said second end portion of said first part disposed adjacent said pilot control element comprises an additional valve seat;

said pilot control element being disposed so that said first part extends toward said first end portion of said first part and beyond said additional valve seat;

said second part of said pilot control element being in contact with said additional valve seat;

said outer tube being a first outer tube;

a second outer tube;

said second outer tube being disposed concentrically about said longitudinal axis of said valve;

said second outer tube having an exterior surface facing away from said valve body, and an interior surface facing toward said valve body;

said interior surface of said second outer tube being disposed a first radial length defined substantially transverse to said longitudinal axis of said valve;

an intermediate tube;

said intermediate tube being disposed between said second outer tube and said valve body;

said intermediate tube having a first surface facing said said valve body and a second surface facing away from said valve body;

said intermediate tube being disposed substantially concentrically about said longitudinal axis of said valve;

said first surface of said intermediate tube being disposed a second radial length defined substantially transverse to said longitudinal axis of said valve;

said first radial length being substantially greater than said second radial length;

said second radial length being substantially the same as said second radial distance;

an exterior chamber;

said exterior chamber being at least in part substantially annular in shape;

at least a portion of said intermediate tube and said second outer tube forming said exterior chamber;

a flow chamber;

said first end portion of said first valve body part forming at least a portion of said flow chamber;

an annular structure;

said annular structure being disposed adjacent said first surface of said intermediate tube;

said annular structure comprising said valve seat;

said annular structure forming a least a portion of said flow chamber;

said flow chamber having fluid communication with said fluid path;

said flow chamber having fluid communication with said passage means;

said intermediate tube comprising a first groove and a second groove;

said first groove being disposed adjacent said valve seat;

said second groove being disposed adjacent said additional valve seat;

fluid communication means for passage of fluid from said valve to said compensating chamber;

said fluid communication means comprising;

said first groove when said pilot control element is opened away from said second valve seat;

said second groove when said valve body is opened away from said valve seat; and

said exterior chamber;

said valve further comprises;

said spring being substantially transverse to said longitudinal axis of said valve;

said spring being disposed adjacent said first valve body part and said extreme second end of said second valve body part;

said passage means being first passage means;

said spring comprises second passage means for passage of damping fluid;

said second passage means comprises at least one recess in said spring;

said intermediate tube comprises an entry bevel; and

said entry bevel being disposed adjacent said flow path.

13. The vibration damper according to claim 5, wherein said valve further comprises:

a spring;

said spring is disposed between said first part and said second part of said valve body; and

said spring is disposed to prestress said first part and said second part axially toward one another.

14. The vibration damper according to claim 13, wherein said valve seat of said valve body comprises one of:

a planar surface; and

a conical surface.

15. The vibration damper according to claim 14, wherein said first portion of said first valve body part comprises passage means for the entry of damping fluid into said first valve body part.

16. The vibration damper according to claim 15, wherein:

at least a portion of said pilot control chamber is disposed in said first valve body part;

said pilot control chamber extends from said first end portion of said first valve body part to said second end portion of said first valve body part;

said pilot control chamber comprises orifices disposed in said first valve body part;

said pilot control chamber comprising sub-chambers adjacent said second valve body part; and

said pilot control chamber extends to said pilot control element.

17. The vibration damper according to claim 16, wherein said said first axial guide is disposed adjacent said second end portion of said first part of said valve body;

and

said first axial guide extends a substantial distance along said longitudinal axis.

18. The vibration damper according to claim 17, wherein said second axial guide is disposed adjacent said second part of said valve body;

said second axial guide is disposed at a substantially greater radial distance from said longitudinal axis of said valve than said first axial guide; and

said first axial guide is disposed at a substantially greater radial distance from said longitudinal axis of said vibration damper cylinder than said second axial guide.

19. The vibration damper according to claim 18, wherein:

said first piece of said first end portion of said first valve body part extends along said longitudinal axis of said valve;

said second piece of said first end portion of said first valve body part comprises said portion of said first end portion of said first part extending toward said valve seat; and

said second piece comprises said spring;

said first part of said valve body further comprises a circular plate;

said circular plate has a first flat surface and a second flat surface opposite said first flat surface;

said first flat surface of said circular plate is substantially transverse to said longitudinal axis of said valve;

said circular plate is in contact with said first valve body part;

said circular plate is disposed between said first axial guide and said second axial guide;

said circular plate is in contact with said second extreme end of said second valve body part;

said valve body comprises a surface area portion for engaging and disengaging with said valve seat; and

said surface area portion comprises one of;

a planar surface; and

a conical surface.

20. The vibration damper according to claim 19, wherein:

said vibration damper further comprises;

another tube;

said another tube being disposed concentrically about said longitudinal axis of said vibration damper;

said another tube being disposed between said cylinder and said outer tube;

a compensating chamber;

said compensating chamber being substantially disposed between said cylinder and said outer tube;

said compensating chamber comprising a fluid path;

said fluid path being substantially disposed between said another tube and said cylinder;

said valve further comprises;

at least a part of said first valve body part being disposed substantially concentrically about said longitudinal axis of said valve;

said pilot control element being a substantially conical-shape structure;

said conical shape structure having a first part and a second part;

said first part comprises a substantially narrow end of said conical-shape structure and said second part comprises a substantially broader end of said conical-shape structure;

wherein said second end portion of said first part disposed adjacent said pilot control element comprises additional valve seat;

said pilot control element being disposed so that said first part extends toward said first end portion of said first part and beyond said additional valve seat;

said second part of said pilot control element being in contact with said additional valve seat;

said outer tube being a first outer tube;

a second outer tube;

said second outer tube being disposed concentrically about said longitudinal axis of said valve;

said second outer tube having an exterior surface facing away from said valve body, and an interior surface facing toward said valve valve;

said interior surface of said second outer tube being disposed a first radial length defined substantially transverse to said longitudinal axis of said valve;

an intermediate tube;

said intermediate tube being disposed between said second outer tube and said valve body;

said intermediate tube having a first surface facing said said valve body and a second surface facing away from said valve body;

said intermediate tube being disposed substantially concentrically about said longitudinal axis of said valve;

said first surface of said intermediate tube being disposed a second radial length defined substantially transverse to said longitudinal axis of said valve;

said first radial length being substantially greater than said second radial length;

said second radial length being substantially the same as-said second radial distance;

an exterior chamber;

said exterior chamber being at least in part substantially annular in shape;

at least a portion of said intermediate tube and said second outer tube forming said exterior chamber;

a flow chamber;

said first end portion of said first valve body part forming at least a portion of said flow chamber;

an annular structure;

said annular structure being disposed adjacent said first surface of said intermediate tube;

said annular structure comprising said valve seat;

said annular structure forming a least a portion of said flow chamber;

said flow chamber having fluid communication with said fluid path;

said flow chamber having fluid communication with said passage means;

said intermediate tube comprising a first groove and a second groove;

said first groove being disposed adjacent said valve seat;

said second groove being disposed adjacent said additional valve seat;

fluid communication means for passage of fluid from said valve to said compensating chamber;

said fluid communication means comprising;

said first groove when said pilot control element is opened away from said second valve seat;

said second groove when said valve body is opened away from said valve seat; and

said exterior chamber;

said valve further comprises;

said passage means being a first passage means;

said circular plate of said first part comprises second passage means for passage of said fluid;

said second passage means comprises one or more recesses in said circular plate;

valve sealing means for sealing said valve from fluid leakage;

said valve sealing means comprises a circular seal member; and

said seal member being disposed between said second valve body part and said second axial guide.