Abstract: A dual-pinion electric power steering device has: a rack shaft that causes a turnable member to turn; a first pinion shaft to which a steering force from a steering wheel is transmitted; a first rack teeth disposed on the rack shaft and capable of meshing with the first pinion shaft; a second pinion shaft to which a rotational driving force from an assist motor is transmitted; a second rack teeth disposed on the rack shaft and capable of meshing with the second pinion shaft; a first pressing member disposed across the rack shaft from the first pinion shaft and configured to press the rack shaft toward the first pinion shaft; and a second pressing member disposed across the rack shaft from the second pinion shaft and configured to press the rack shaft toward the second pinion shaft. The first pressing member has a lower rigidity than the second pressing member.

Abstract: A dual-pinion electric power steering device has: a rack shaft that causes a turnable member to turn; a first pinion shaft to which a steering force from a steering wheel is transmitted; a first rack teeth disposed on the rack shaft and capable of meshing with the first pinion shaft; a second pinion shaft to which a rotational driving force from an assist motor is transmitted; a second rack teeth disposed on the rack shaft and capable of meshing with the second pinion shaft; a first pressing member disposed across the rack shaft from the first pinion shaft and configured to press the rack shaft toward the first pinion shaft; and a second pressing member disposed across the rack shaft from the second pinion shaft and configured to press the rack shaft toward the second pinion shaft. The first pressing member has a lower rigidity than the second pressing member.

Abstract: Electric power steering system comprises an electric motor (9) for producing a steering assist force reducing a steering effort of a vehicle operator and a control unit (21) determining a control value for the electric motor, the control unit being configured to determine the control value by selecting a map representing a relationship between a vehicle state variable and a control value for each of a plurality of control modes. When switching control modes, the control unit gradually changes the control value from that obtained from a map corresponding to a preceding control mode to that of a following control mode. A different time period of gradual transition from the preceding control mode to the following control mode is selected depending on those control modes.

Abstract: A vehicle steering system includes a sound absorbing material made of sponge and attached to an elastic joint which connects a second steering shaft extending from a steering wheel and a third steering shaft extending from a steering gear box to each other. The sound absorbing material faces an opening in a joint cover which is mounted on a dashboard and through which the second steering shaft passes. Therefore, the sound absorbing material absorbs noise which is produced in the steering gear box such that the noise does not pass from the engine room side through the opening in the joint cover to the vehicle compartment side, thereby preventing transmission of the noise to the vehicle compartment side. Further, the sound absorbing material requires only a simple shape and construction, thereby reducing the cost. Furthermore, the sound absorbing material does not come into sliding contact with the second steering shaft, and thus does not produce sliding noise or sliding resistance.

Abstract: A vehicle steering system includes a sound absorbing material made of sponge and attached to an elastic joint which connects a second steering shaft extending from a steering wheel and a third steering shaft extending from a steering gear box to each other. The sound absorbing material faces an opening in a joint cover which is mounted on a dashboard and through which the second steering shaft passes. Therefore, the sound absorbing material absorbs noise which is produced in the steering gear box such that the noise does not pass from the engine room side through the opening in the joint cover to the vehicle compartment side, thereby preventing transmission of the noise to the vehicle compartment side. Further, the sound absorbing material requires only a simple shape and construction, thereby reducing the cost. Furthermore, the sound absorbing material does not come into sliding contact with the second steering shaft, and thus does not produce sliding noise or sliding resistance.