Vehicle steering device

Claim 2

A vehicle steering device according to claim 1, wherein said means (50, 150, 250, 390, 416) for releasing the steering inhibition are designed so that the degree of steering inhibition is matched to the strength of the driver's steering effort.

Claim 3

The vehicle steering device according to claim 1 or 2, further comprising: means (73, 74, 323, 324, 415b, 415d) for detecting an obstacle calling for the application of steering inhibition in the right steering direction; and means (75, 76, 325, 326, 415a, 415c) for detecting an obstacle calling for the application of steering inhibition in the left steering direction; wherein the application of steering inhibition is confined to steering in the direction in which the obstancle is detected.

Claim 4

The vehicle steering device according to any preceding claim, further comprising: a vehicle velocity detection means (172); wherein when the vehicle's velocity falls below a preset value, the steering device itself is switched to the second mode in which the steering inhibition is released.

Claim 5

The vehicle steering device according to any preceding claim, further comprising: a deceleration operation detection means (173); wherein when a deceleration operation is detected, the steering device itself is switched to the second mode in which the steering inhibition is released.

Claim 6

The vehicle steering device according to any preceding claim, wherein: the speed at which the steering inhibition is released is reduced in accordance with the strength of the driver's steering effort.

Claim 7

The vehicle steering device according to any preceding claim, further comprising: a hydraulic actuator (18) having a right hydraulic fluid chamber (21) for the generation of steering assistance power to the right and a left hydraulic fluid chamber (22) for the generation of steering assistance power to the left; a control valve (23), which channels high pressure fluid from a pump (37) into one of the hydaulic fluid chambers and drains low pressure fluid from the other hydraulic fluid chamber into a fluid tank (41), in accordance with the dircetion of steering and the strength of the driver's steering effort; means (73, 74) for detecting an obstacle calling for the application of steering inhibition in the right steering direction; means (75, 76) for detecting an obstacle calling for the application of steering inhibition in the left steering direction; means (71) for issuing a right steering inhibition signal following the detection of the obstacle calling for the application of steering inhibition in the right steering direction, and issuing a left steering inhibition signal following the detection of the obstacle calling for the application of steering inhibition in the left steering direction; and means (51, 52, 61, 62) for applying steering inhibition by high pressure hydraulic fluid supplied via the control valve at a pressure in accordance with the strength of the driver's steering effort, in response to the right and/or left steering inhibition signal.

Claim 8

The vehicle steering device according to any preceding claim, further comprising: a hydraulic actuator (18) having a right hydraulic fluid chamber (21) for the generation of steering assistance power to the right and a left hydraulic fluid chamber (22) for the generation of steering assistance power to the left; a control valve (23), which channels high pressure fluid from a pump (31) into one of the hydraulic fluid chambers and drains low pressure fluid from the other hydraulic fluid chamber into a fluid tank (41), in accordance with the direction of steering; means (73, 74) for detecting an obstacle calling for the application of steering inhibition in the right steering direction; means (75, 76) for detecting an obstacle calling for the application of steering inhibition in the left steering direction; a flow control valve (51, 51') for right steering inhibition located in the hydraulic fluid channel between the hydraulic actuator (18) and the control valve (23) a flow control valve (52, 52') for left steering inhibition located in the hydraulic fluid channel between the hydraulic actuator (18) and the control valve (23); means (71) for issuing a right steering inhibition signal following the detection of the obstacle calling for the application of steering inhibition in the right steering direction, and issuing a left steering inhibition signal following the detection of the obstacle calling for the application of steering inhibition in the left steering direction; means (61, 65') for operating the flow control valve (51, 51') for right steering inhibition such that the issue of the right steering inhibition signal results in a reduction in the flow of hydraulic fluid for providing steering assistance power to the right; and means (62, 65') for operating the flow control valve (52, 52') for left steering inhibition such that the issue of the left steering inhibition signal results in a reduction in the flow of hydraulic fluid for providing steering assistance power to the left; wherein the flow control valve (51, 51') for right steering inhibition is controlled such that it does not cause a reduction in the flow of hydraulic fluid for providing steering assistance power to the left, and the flow control valve (52, 52') for left steering inhibition is controlled such that it does not cause a reduction in the flow of hydraulic fluid for providing steering assistance power to the right.

Claim 9

The vehicle steering device according to claim 8, wherein: the right steering inhibition signal is issued in response to the detection of the obstacle with which the vehicle is in danger of colliding in its right steeering direction; and the left steering inhibition signal is issued in response to the detection of the obstacle with which the vehicle is in danger of colliding in its left steering direction.

Claim 10

The vehicle steering device according to claim 8 or 9, wherein: when the control valve (23) channels high pressure hydraulic fluid to the hydraulic actuator (18) at a pressure in accordance with the strength of the driver's steering effort, each flow control valve (51, 52) reduces the flow of hydraulic fluid for the generation of steering assistance power in accordance with the pressure of the high pressure hydraulic fluid.

Claim 11

The vehicle steering device according to claim 10, wherein: each of the flow control valve (51, 52) has a pressure sensitive chamber (56) and a valve member (55) that move in accordance with the pressure of the hydraulic fluid in the pressure sensitive chamber (56); the means for operating each of the flow control valves (51, 52) has a hydraulic fluid channel switching valve (61, 62); each said switching valve (61, 62) connects the pressure sensitive chamber (56) to the high pressure side in response to the steering inhibition signal, and connects the pressure sensitive chamber (56) to the low pressure side by canceling of the steering inhibition signal; and the flow of hydraulic fluid for the generation of steering assistance power is reduced in accordance with the movement of the valve member (55), which moves in accordance with the pessure in the pressure sensitive chamber (56).

Claim 12

The vehicle steering device according to any of claims 8 to 11, further comprising: a fluid channel that refluxes the high pressure hydraulic fluid supplied to one or other of the flow control valves (51, 52, 51', 52') to the low pressure side, when the one or other of the flow control valves (51, 52, 51', 52') is in operation and the flow of hydraulic fluid for the generation of steering assistance power is at is lowest.

Claim 13

The vehicle steering device according to any of claims 1 to 6, further comprising: a motor (413) linked to a steering mechanism including a steering wheel (401), for the generation of steering assistance power when the steering wheel (401) is turned; a drive control means (414) which is determines a target control value in accordance with input signals received and which uses the target control value to drive the motor; a sensor (410) to detect the vehicle's running mode and issue a running mode signal; a danger prediction means (415a, 415b, 415c, 415d) which outputs a danger prediction signal in response to approach of the vehicle to an obstacle; and a danger avoidance safety control means (416) connected to the sensor (410), the danger prediction means (415a, 415b, 415c, 415d), and the drive control means (414); wherein: the danger avoidance safety control means (416) output the running mode signal from the sensor (410) to the drive control means (414) without modification when the danger prediction signal from the danger prediction means (415a, 415b, 415c, 415d) is absent; and the danger avoidance safety control means (416) modifies the running mode signal from the sensor (410) in accordance with the content of the danger prediction signal and then outputs the modified running mode signal to the drive control means (414) on receipt of the danger prediction signal from the danger prediction means (415a, 415b, 415c, 415d).

Claim 14

The vehicle steering device according to claim 13, wherein: the danger prediction signal indicating the direction of a detected obstacle in relation of the driver's vehicle, and the safety control means (416) converts the running mode signal received from the sensor (410) into an another running mode signal corresponding to the target control value for inhibiting the driver's vehicle from traveling in the direction of the detected obstacle.