Variable gear ratio hydraulic power steering device
First Claim
1. A variable gear ratio hydraulic power steering device having a variable ratio transmission mechanism for varying the rotation transmission ratio V2/V1 between the rotational angle V1 of a first steering shaft coupled to a steering handle and the rotational angle V2 of a second steering shaft coupled to a pinion shaft, a transmission ratio controlling controller for controlling the variable ratio transmission mechanism, a flow volume control valve for controlling the discharge flow volume of an oil pump which circulates operating fluid which provides an assist force to the steering device, and a valve controlling controller for controlling the flow volume control valve, wherein:
- the variable ratio transmission mechanism is provided with a lock mechanism for restricting relative rotation between the first steering shaft and the second steering shaft;
the valve controlling controller is provided with a memory for storing main and secondary flow volume control maps each mapping various flow volume control values for controlling the flow volume control valve, and a detector adapted to detect the operational state of the lock mechanism; and
the valve controlling controller is constructed to control the flow volume control valve by the use of the main flow volume control map when the lock mechanism permits the relative rotation between the first and second steering shafts and to control the flow volume control valve by the use of the secondary flow volume control map when the lock mechanism restricts the relative rotation between the first and second steering shafts.
3 Assignments
0 Petitions
Accused Products
Abstract
A variable gear ratio hydraulic power steering device 1 is provided with a variable ratio transmission mechanism 7 for varying the rotation transmission ratio between the rotational angle of a steering handle 31 and the rotational angle of a pinion shaft 33 and a flow volume control valve 40 for controlling the discharge flow volume of an oil pump 10 which circulates operating fluid. The variable ratio transmission mechanism 7 has a lock mechanism 75. A valve controlling controller 50 for controlling the flow volume control valve 40 switches main and secondary flow volume control maps for controlling the flow volume control valve 40, in dependence on the operational state of the lock mechanism 75. Thus, a failsafe function for the variable ratio transmission mechanism 7 is given to the variable gear ratio hydraulic power steering device 1.
18 Citations
10 Claims
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1. A variable gear ratio hydraulic power steering device having a variable ratio transmission mechanism for varying the rotation transmission ratio V2/V1 between the rotational angle V1 of a first steering shaft coupled to a steering handle and the rotational angle V2 of a second steering shaft coupled to a pinion shaft, a transmission ratio controlling controller for controlling the variable ratio transmission mechanism, a flow volume control valve for controlling the discharge flow volume of an oil pump which circulates operating fluid which provides an assist force to the steering device, and a valve controlling controller for controlling the flow volume control valve, wherein:
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the variable ratio transmission mechanism is provided with a lock mechanism for restricting relative rotation between the first steering shaft and the second steering shaft; the valve controlling controller is provided with a memory for storing main and secondary flow volume control maps each mapping various flow volume control values for controlling the flow volume control valve, and a detector adapted to detect the operational state of the lock mechanism; and the valve controlling controller is constructed to control the flow volume control valve by the use of the main flow volume control map when the lock mechanism permits the relative rotation between the first and second steering shafts and to control the flow volume control valve by the use of the secondary flow volume control map when the lock mechanism restricts the relative rotation between the first and second steering shafts. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification