Stroke sensor system and LC oscillation circuit
A stroke sensor system includes a vehicle-body-side member, a wheel-side member, and a movement-amount deriving section. The movement-amount deriving section derives a movement amount of relative movement between the vehicle-body-side member and the wheel-side member. At least a part of one of the vehicle-body-side member and the wheel-side member is a conductor, and the other is provided with a coil. The movement-amount deriving section includes an even number of capacitors and an even number of exciting sections. The even number of capacitors are electrically coupled to the coil and configure an LC resonance section. The even number of exciting sections are for exciting an oscillation waveform output by the LC resonance section. The even number of capacitors and the even number of exciting sections are divided into equal numbers to configure a balanced circuit. The movement-amount deriving section derives the movement amount based on the oscillation waveform.
1. A stroke sensor system comprising:
a vehicle-body-side member formed in a tubular shape and located at a vehicle body side;
a wheel-side member formed in a tubular shape, located at a wheel side, coupled to the vehicle-body-side member, and configured to move relative to the vehicle-body-side member in an axial direction of the vehicle-body-side member; and
a movement-amount deriving section configured to derive an axial movement amount of relative movement between the vehicle-body-side member and the wheel-side member, wherein
at least a part of one of the vehicle-body-side member and the wheel-side member is an electric conductor, and other of the vehicle-body-side member and the wheel-side member is provided with a coil,
the movement-amount deriving section comprises:
an even number of capacitors electrically coupled to the coil and configuring an LC resonance section; and
an even number of exciting sections for exciting an oscillation waveform output by the LC resonance section by the relative movement between the vehicle-body-side member and the wheel-side member,
the even number of capacitors and the even number of exciting sections are divided into a plurality of groups of same number of the capacitor and a plurality of groups of same number of the exciting section respectively to configure a balanced circuit,
the movement-amount deriving section derives the axial movement amount based on the oscillation waveform,
the electric conductor and the coil move relative to each other by the relative movement between the vehicle-body-side member and the wheel-side member, whereby the axial movement amount is calculated from a resonance frequency of the LC resonance section, which varies according to a change in an inductance of the coil due to the movement of the electric conductor relative to the coil, and
the change in the inductance of the coil corresponds to a change in an overlapping length of the electric conductor and the coil.
2. The stroke sensor system according to claim 1 , further comprising a wire that couples in series the capacitors divided into the plurality of groups of same number of the capacitor, wherein
the wire is grounded.
3. The stroke sensor system according to claim 1 , wherein the exciting sections output the oscillation waveform by differential comparison of potentials on both sides of the coil.
4. The stroke sensor system according to claim 2 , wherein the exciting sections output the oscillation waveform by differential comparison of potentials on both sides of the coil.
5. The stroke sensor system according to claim 1 , further comprising a wire that couples the capacitors divided into the plurality of groups of same number of the capacitor, and a bypass capacitor that is provided at the wire.
6. The stroke sensor system according to claim 2 , further comprising a bypass capacitor that is provided at the wire.
7. The stroke sensor system according to claim 3 , further comprising a wire that couples the capacitors divided into the plurality of groups of same number of the capacitor, and a bypass capacitor that is provided at the wire.
8. The stroke sensor system according to claim 4 , further comprising a bypass capacitor that is provided at the wire.
9. The stroke sensor system according to claim 1 , further comprising Zener diodes coupled in parallel to the capacitors divided into equal numbers.
10. The stroke sensor system according to claim 2 , further comprising Zener diodes coupled in parallel to the capacitors divided into equal numbers.
11. The stroke sensor system according to claim 3 , further comprising Zener diodes coupled in parallel to the capacitors divided into equal numbers.
12. The stroke sensor system according to claim 4 , further comprising Zener diodes coupled in parallel to the capacitors divided into equal numbers.
13. The stroke sensor system according to claim 5 , further comprising Zener diodes coupled in parallel to the capacitors divided into equal numbers.
14. The stroke sensor system according to claim 6 , further comprising Zener diodes coupled in parallel to the capacitors divided into equal numbers.
15. The stroke sensor system according to claim 7 , further comprising Zener diodes coupled in parallel to the capacitors divided into equal numbers.
16. The stroke sensor system according to claim 8 , further comprising Zener diodes coupled in parallel to the capacitors divided into equal numbers.