FREQUENCY HOPPING FOR SMART AIR SPRINGS

• US 20140139352A1
• Filed: 11/20/2013
• Published: 05/22/2014
• Est. Priority Date: 11/21/2012
• Status: Active Grant

• Current Assignee: Infinity Engineered Products, LLC
• Original Assignee: Veyance Technologies Incorporated (Continental AG)
• Inventors: May, Lutz
• Granted Patent: US 9,349,281 B2
• Time in Patent Office: Days
• US Class Current: 340/870.07
• CPC Class Codes: B60G 11/27 wherein the fluid is a gas
• CPC Class Codes: B60G 2400/252 vertical
• CPC Class Codes: B60N 2/0272 using sensors or detectors for detecting the position of seat parts
• CPC Class Codes: B60N 2/525 using gas
• CPC Class Codes: F16F 2230/08 Sensor arrangement
• CPC Class Codes: F16F 9/05 the flexible wall being of the rolling diaphragm type
• CPC Class Codes: F16F 9/3292 Sensor arrangements
• CPC Class Codes: G08C 17/02 using a radio link
• CPC Class Codes: H04B 1/713 using frequency hopping

Abstract

The subject invention relates to an air spring height sensor comprising a transmitter unit (102) for transmitting a height measuring signal, a receiver unit (101) for sensing a height signal, a carrier frequency switching unit (103), and an evaluation unit (200). The receiver unit and the transmitter unit are adapted for being mounted to opposing mounting elements (10, 20) of an air spring (1). The transmitter unit is switchable between different carrier frequencies (121, 122) of a height measuring signal. The evaluation unit comprises a frequency filter (213) being switchable between different carrier frequencies, wherein the carrier frequency switching unit is adapted for switching the carrier frequency of the frequency filter at a predetermined first point of time and the corresponding carrier frequency of the transmitter unit at a predetermined second point of time, wherein the first point of time is prior to the second point of time.

Claims

1. An air spring height sensor comprising:

a transmitter unit for transmitting a height measuring signal,

a receiver unit for sensing a height signal,

a carrier frequency switching unit, and

an evaluation unit,

wherein the transmitter unit is switchable between different carrier frequencies of a height measuring signal,

wherein the evaluation unit comprises a frequency filter being switchable between different carrier frequencies), and

wherein the carrier frequency switching unit is adapted for switching the carrier frequency of the frequency filter at a predetermined first point of time (t1) and the corresponding carrier frequency of the transmitter unit at a predetermined second point of time (t2), wherein the first point of time is prior to the second point of time.

2. The air spring height sensor according to claim 1, wherein the receiver unit and the transmitter unit are adapted for being mounted to opposing mounting elements of an air spring (1).

3. The air spring height sensor according to claim 1, wherein the evaluation unit is adapted for detecting after the first point of time and before the second point of time whether the carrier frequency is sufficiently free of interferences and for subsequently evaluating the sensed height signal when the carrier frequency of the transmitter unit corresponds to the carrier frequency of the frequency filter and the carrier frequency is sufficiently free of interferences.

4. The air spring height sensor according to claim 2, wherein the evaluation unit is adapted for detecting after the first point of time and before the second point of time whether the carrier frequency is sufficiently free of interferences and for subsequently evaluating the sensed height signal when the carrier frequency of the transmitter unit corresponds to the carrier frequency of the frequency filter and the carrier frequency is sufficiently free of interferences.

5. The air spring height sensor according to claim 1, wherein the carrier frequency switching unit is adapted for alternately switching the carrier frequency of the frequency filter and the transmitter unit between a first carrier frequency and a second carrier frequency.

6. The air spring height sensor according to claim 1, wherein the carrier frequency switching unit is adapted for periodically switching the carrier frequency of the receiver unit at a periodic predetermined first point of time (t1) and the corresponding carrier frequency of the transmitter unit at a respective predetermined second point of time (t2).

7. The air spring height sensor according to claim 1, wherein the air spring height sensor is adapted for interrupting the transmission of the transmitter unit at least partially between the first point of time and the second point of time.

8. The air spring height sensor according to claim 1, wherein the air spring height sensor is adapted for interrupting the transmission of the transmitter unit between the first point of time and the second point of time.

9. The air spring height sensor according to claim 1, wherein the carrier frequency is between 1 kHz and 1 MHz, in particular the carrier frequency is between 10 kHz and 100 kHz.

10. The air spring height sensor according to claim 5, wherein an alternating rate from one of the first carrier frequency and the second carrier frequency to the other one from the first carrier frequency and the second carrier frequency is between 1 Hz and 1 kHz.

11. The air spring height sensor according to claim 10, wherein the alternating rate is within the range of 10 Hz to 100 Hz.

12. The air spring height sensor according to claim 1, wherein the ratio of the duration between the first point of time and the second point of time and the duration where the carrier frequency of the transmitter unit corresponds to the carrier frequency of the frequency filter is between 0.2 and 5.

13. The air spring height sensor according to claim 1, wherein the ratio of the duration between the first point of time and the second point of time and the duration where the carrier frequency of the transmitter unit corresponds to the carrier frequency of the frequency filter is between 0.5 and 2.

14. The air spring height sensor according to claim 1, wherein the ratio of the duration between the first point of time and the second point of time and the duration where the carrier frequency of the transmitter unit corresponds to the carrier frequency of the frequency filter is between 0.8 and 1.2.

15. An air spring comprising:

a first mounting element being adapted for being mounted to a first vehicle portion;

a second mounting element being adapted for being mounted to a second vehicle portion being springy movable with respect to the first vehicle portion;

an air volume limited by a resilient belly having a first edge and a second edge, which belly with the first edge is sealed to the first mounting element and with the second edge is sealed to the second mounting edge;

the air spring height sensor of claim 1,

wherein the transmitter unit is mounted to the first mounting element, and wherein the receiver unit is mounted to the second mounting element as to sense a height signal with respect to the first mounting element.

16. An air spring height measuring method, the method comprising:

switching at a predetermined first point of time a carrier frequency of a frequency filter of an evaluation unit, evaluating a sensed height signal of a receiver unit being mounted to a first mounting element of an air spring, from one of a first carrier frequency and a second carrier frequency to the other one of the first carrier frequency and the second carrier frequency,

detecting after the first point of time whether the carrier frequency is sufficiently free of interferences,

switching at a predetermined second point of time the carrier frequency of a transmitter uni, for transmitting a height measuring signal, which transmitter unit is being mounted to a second mounting element of an air spring, to a corresponding carrier frequency of the frequency filter, and

evaluating the sensed height signal when the carrier frequency of the transmitter unit corresponds to the carrier frequency of the frequency filter and if the carrier frequency is sufficiently free of interferences.

17. The air spring height measuring method according to claim 16, wherein switching the carrier frequency of the frequency filter comprises periodically switching the carrier frequency at a periodic predetermined first point of time and switching the carrier frequency of the transmitting unit comprises periodically switching the carrier frequency at a respective periodic predetermined second point of time.

18. The air spring height measuring method according to claims 16, further comprising interrupting the transmission of the transmitter unit at least partially between the first point of time and the second point of time.

19. The air spring height measuring method according to claims 17, further comprising interrupting the transmission of the transmitter unit at least partially between the first point of time and the second point of time.