EP0316932A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Rear wheel steering apparatus for automobile
Assignee: Mazda Motor Corp
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Filing: 1988-11-18
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Granted: —
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Expires: 2008-11-18
Abstract
Abstract A rear wheel steering apparatus for an automobile detects a vehicle speed and turns rear wheels at a rear wheel turning angle ratio according to the detected vehicle speed upon turning of front wheels. The apparatus includes a vehicle speed detection section for detecting a vehicle speed, a setting section for setting a rear wheel turning angle ratio in accordance with the vehicle speed detected by the vehicle speed detection section, a travel detection section detecting a travel state of a vehicle, a change section for changing turning angle ratio control by the setting section to fail-safe control when a detection output from the vehicle speed detection section is zero and the travel detection section detects the travel state of the vehicle, a brake detection section for detecting a brake operation state, and an inhibition section for inhibiting a change from the normal turning angle ratio control to the fail-safe control by the change section when the brake detection section detects a brake operation state.
Inventors
- 👤 Hiroshi Ohmura
- 👤 Takashi Nakashima
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 01:46
CPC Classifications
B; B62; B62D; B62D6/00; B62D6/02; B62D7/00; B62D7/06; B62D7/14; B62D7/148
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
105 words
A rear wheel steering apparatus for an automobile, which detects a vehicle speed and turns rear wheels at a rear wheel turning angle ratio according to the detected vehicle speed upon turning of front wheels, comprising: discrimination means for discriminating a travel state; first setting means for, when said discrimination means determines a normal travel state, setting a rear wheel turning angle ratio in accordance with a first characteristic according to the detected vehicle speed; and second setting means for, when said discrimination means detects a lock state of wheels, setting the rear wheel turning angle ratio in accordance with a second characteristic for stabilization.
Claim 2
Dependent Claim
105 words
A rear wheel steering apparatus for an automobile, which detects a vehicle speed and turns rear wheels at a rear wheel turning angle ratio according to the detected vehicle speed upon turning of front wheels, comprising: discrimination means for discriminating a travel state; first setting means for, when said discrimination means determines a normal travel state, setting a rear wheel turning angle ratio in accordance with a first characteristic according to the detected vehicle speed; and second setting means for, when said discrimination means detects a lock state of wheels, setting the rear wheel turning angle ratio in accordance with a second characteristic for stabilization.
Claim 3
Dependent Claim
54 words
The rear wheel steering apparatus according to claim 1, characterized in that said discrimination means determines the lock state of the wheels when a brake switch is turned on, the detected vehicle speed is substantially 0 km/h, and the detected vehicle speed immediately before 0 km/h is detected is not less than 30 km/h.
Claim 4
Dependent Claim
48 words
The rear wheel steering apparatus according to claim 1, characterized in that said second setting means is set to have the second characteristic for stabilization such that the rear wheel turning angle ratio is fixed to a ratio according to the detected vehicle speed immediately before lock detection.
Claim 5
Dependent Claim
37 words
The rear wheel steering apparatus according to claim 1, characterized in that said second setting means is set to have the second characteristic for stabilization such that the rear wheel turning angle ratio is fixed to zero.
Claim 6
Dependent Claim
39 words
The rear wheel steering apparatus according to claim 1, characterized in that said second setting means is set to have the second characteristic for stabilization such that a change rate of the rear wheel turning angle ratio is lowered.
Claim 7
Dependent Claim
25 words
The rear wheel steering apparatus according to claim 1, characterized in that said discrimination means comprises vehicle speed detection means for detecting a vehicle speed.
Claim 8
Dependent Claim
131 words
The rear wheel steering apparatus according to claim 6, characterized by further comprising: setting means for setting the rear wheel turning angle ratio in accordance with the vehicle speed detected by said vehicle speed detection means; abnormality discrimination means for determining that an output from said vehicle speed detection means is quickly decreased over a predetermined value; change means for, when said abnormality discrimination means detects that the output from said vehicle speed detection means is quickly decreased, changing turning angle ratio control by said setting means to fail-safe control; brake detection means for detecting a brake operation state; and inhibition means for, when said brake detection means detects the brake operation state, inhibiting a change from the normal turning angle ratio control to the fail-safe control by said change means.
Claim 9
Dependent Claim
63 words
The rear wheel steering apparatus according to claim 7, characterized in that said vehicle speed detection means comprises a transaxle side first vehicle speed sensor, and a speedometer side second vehicle speed sensor, and detects a quick decrease in output from said vehicle speed detection means when one of said first and second vehicle speed sensors is quickly decreased below a predetermined value.
Claim 10
Dependent Claim
51 words
The rear wheel steering apparatus according to claim 7, characterized in that said setting means uses a higher value of the output results from the first and second vehicle speed sensors as a detected vehicle speed, and sets the rear wheel turning angle ratio in accordance with the detected vehicle speed.
Claim 11
Dependent Claim
40 words
The rear wheel steering apparatus according to claim 6, characterized by further comprising: inhibition means for, when the detection output from said vehicle speed detection means is quickly increased over a predetermined value, inhibiting setting by said second setting means.
Claim 12
Dependent Claim
31 words
The rear wheel steering apparatus according to claim 10, characterized in that said inhibition means sets the predetermined value to be a value for detecting a wheel spin of the wheels.
Claim 13
Dependent Claim
44 words
The rear wheel steering apparatus according to claim 10, characterized in that said vehicle speed detection means comprises a lead switch type vehicle speed sensor, and said inhibition means sets the predetermined value to be a value for detecting chattering occurring during detection operation.
Claim 14
Dependent Claim
53 words
The rear wheel steering apparatus according to claim 6, characterized in that said second setting means sets a lock control state by changing from the normal first characteristic to the second characteristic for stabilization, and characterized by further comprising: cancel means for, when a predetermined condition is satisfied, canceling the lock control state.
Claim 15
Dependent Claim
62 words
The rear wheel steering apparatus according to claim 13, characterized in that said cancel means changes the rear wheel turning angle ratio from the second characteristic to the first characteristic by said setting means after a predetermined period of time has passed from detection of the lock state of the wheels by said lock detection means, thereby canceling the lock control state.
Claim 16
Dependent Claim
59 words
The rear wheel steering apparatus according to claim 14, characterized in that said cancel means sets the predetermined period of time to be a time required for, when the brake pedal is kept depressed and a vehicle slips along a road surface while the wheels are locked, stopping the vehicle by friction between the wheels and the road surface.
Claim 17
Dependent Claim
54 words
The rear wheel steering apparatus according to claim 13, characterized in that said cancel means changes the rear wheel turning angle ratio from the second characteristic to the first characteristic when the detected vehicle speed from said vehicle speed detection means substantially coincides with an actual vehicle speed, thereby canceling the lock control state.
Claim 18
Dependent Claim
56 words
The rear wheel steering apparatus according to claim 16, characterized in that said cancel means determines that the detected vehicle speed substantially coincides with the actual vehicle speed when a currently detected vehicle speed coincides with the detected vehicle speed immediately before the lock state of the wheels is detected, and cancels the lock control state.
Claim 19
Dependent Claim
79 words
The rear wheel steering apparatus according to claim 13, characterized by further comprising: brake detection means for detecting a depression state of a brake pedal, and characterized in that said cancel means changes the rear wheel turning angle ratio from the second characteristic to the first characteristic by said setting means when a predetermined period of time has passed after depression detection of the brake pedal by said brake detection means is stopped, thereby canceling the lock control state.
Claim 20
Dependent Claim
41 words
The rear wheel steering apparatus according to claim 18, characterized in that said cancel means sets the predetermined period of time to be a time required for the wheels to grip a road surface after a braking force is essentially released.
Claim 21
Dependent Claim
66 words
The rear wheel steering apparatus according to claim 13, characterized in that said cancel means changes the rear wheel turning angle ratio from the first characteristic to the second characteristic when a vehicle speed signal other than a signal indicating a vehicle speed of zero is continuously input from said vehicle speed detection means for a predetermined period of time, thereby canceling the lock control state.
Claim 22
Dependent Claim
34 words
The rear wheel steering apparatus according to claim 20, characterized in that said cancel means sets the predetermined period of time to be a time enough for the wheels to grip a road surface.
Claim 23
Dependent Claim
78 words
The rear wheel steering apparatus according to claim 1, characterized in that said discrimination means comprises a plurality of vehicle speed detection means for detecting a vehicle speed, discriminates the lock state of the wheels using the detection output from one of said plurality of vehicle speed detection means, and said first and second setting means set the rear wheel turning angle ratio in accordance with the vehicle speeds detected by said plurality of vehicle speed detection means.
Claim 24
Dependent Claim
35 words
The rear wheel steering apparatus according to claim 22, characterized in that said plurality of vehicle speed detection means comprise a transaxle side first vehicle speed sensor, and a speedometer side second vehicle speed sensor.
Claim 25
Dependent Claim
44 words
The rear wheel steering apparatus according to claim 23, characterized in that said discrimination means uses the output from said first vehicle speed sensor as a detected vehicle speed, and performs lock discrimination in accordance with the output from said first vehicle speed sensor.
Claim 26
Dependent Claim
161 words
A rear wheel steering apparatus for an automobile, which detects a vehicle speed and turns rear wheels at a rear wheel turning angle ratio according to the detected vehicle speed upon turning of front wheels, characterized by comprising: vehicle speed detection means for detecting a vehicle speed; setting means for setting a rear wheel turning angle ratio in accordance with the vehicle speed detected by said vehicle speed detection means; travel detection means for detecting a travel state of a vehicle; change means for, when a detection output from said vehicle speed detection means is zero and said travel detection means detects the travel state of the vehicle, changing turning angle ratio control by said setting means to fail-safe control; brake detection means for detecting a brake operation state; and inhibition means for, when said brake detection means detects a brake operation state, inhibiting a change from the normal turning angle ratio control to the fail-safe control by said change means.
Claim 27
Dependent Claim
161 words
A rear wheel steering apparatus for an automobile, which detects a vehicle speed and turns rear wheels at a rear wheel turning angle ratio according to the detected vehicle speed upon turning of front wheels, characterized by comprising: vehicle speed detection means for detecting a vehicle speed; setting means for setting a rear wheel turning angle ratio in accordance with the vehicle speed detected by said vehicle speed detection means; travel detection means for detecting a travel state of a vehicle; change means for, when a detection output from said vehicle speed detection means is zero and said travel detection means detects the travel state of the vehicle, changing turning angle ratio control by said setting means to fail-safe control; brake detection means for detecting a brake operation state; and inhibition means for, when said brake detection means detects a brake operation state, inhibiting a change from the normal turning angle ratio control to the fail-safe control by said change means.
References Cited (Backward Citations)
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