Continuously Variable Damper Device
First Claim
1. A damper device comprising:
- a cylinder with a piston that separates the cylinder in a first chamber and a second chamber, which chambers can be filled with a hydraulic fluid;
a bypass channel between said first and second chamber and a valve member connected thereto, said valve member comprising a coil unit for generating a magnetic field;
a substantially closed magnetic loop for guiding the magnetic field generated by the coil unit, the magnetic loop comprising a guide member and a closing member, said closing member being moveable relative to the guide member in a first direction for opening and closing the bypass channel, said magnetic loop further comprising a first gap between the guide member and closing member for allowing said movement of the closing member;
a spring device arranged to place the closing member under spring bias in said first direction; and
a non-magnetic spacer arranged in the first gap and connected to the closing member and/or the guide member,wherein driving the coil unit generates a magnetic force acting on the closing member urging it to move against the spring bias towards the guide member thereby lowering the first gap,characterized in that the magnetic loop has a first magnetic reluctance attributed to the first gap and a second magnetic reluctance attributed to a remainder of the magnetic loop, wherein the magnetic loop is configured such that the second magnetic reluctance increases at least during part of the movement of the closing member towards the guide member.
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Accused Products
Abstract
The present invention is related to a damper device (1). More in particular, the present invention is related to a damper device for which the damping force can be varied using a magnetically actuated closing member (33) with which a bypass channel (15) can be closed or opened. According to the present invention, the magnetic reluctance of the magnetic loop for guiding the magnetic field (8) is configured such that a too strong of an upward bending of the magnetic force versus closing member displacement curve is prevented. This prevents the system from obtaining multiple settling points for the closing member for a given current value. Consequently, the damper device is more stable and the damping force offered by it can be controlled more accurately.
40 Citations
32 Claims
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1. A damper device comprising:
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a cylinder with a piston that separates the cylinder in a first chamber and a second chamber, which chambers can be filled with a hydraulic fluid; a bypass channel between said first and second chamber and a valve member connected thereto, said valve member comprising a coil unit for generating a magnetic field; a substantially closed magnetic loop for guiding the magnetic field generated by the coil unit, the magnetic loop comprising a guide member and a closing member, said closing member being moveable relative to the guide member in a first direction for opening and closing the bypass channel, said magnetic loop further comprising a first gap between the guide member and closing member for allowing said movement of the closing member; a spring device arranged to place the closing member under spring bias in said first direction; and a non-magnetic spacer arranged in the first gap and connected to the closing member and/or the guide member, wherein driving the coil unit generates a magnetic force acting on the closing member urging it to move against the spring bias towards the guide member thereby lowering the first gap, characterized in that the magnetic loop has a first magnetic reluctance attributed to the first gap and a second magnetic reluctance attributed to a remainder of the magnetic loop, wherein the magnetic loop is configured such that the second magnetic reluctance increases at least during part of the movement of the closing member towards the guide member. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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Specification