JPH0221346Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electric power steering device for an automobile.

Electric power steering devices have already been developed that reduce the steering force by detecting the steering torque of the steering shaft and applying the corresponding auxiliary steering force through the rotation of an electric motor (for example, 5168), a rack-and-pinion type electric power steering device in which an auxiliary steering force imparting mechanism using an electric motor is incorporated into a rack-and-pinion type steering device has already been disclosed in Utility Model Application Publication No. 120164/1983. ing.

In a conventional rack-and-pinion type electric power steering device, a manual side pinion, which is rotated by operating a steering handle, meshes with the rack teeth of a rack shaft that is slidably supported in the axial direction within a steering gear box. Since the structure is such that an auxiliary pinion rotated by an electric motor meshes with the rack teeth with which the manual side pinion is meshed, the auxiliary pinion must be arranged parallel to the manual side pinion,
There is a problem in that the installation position of the electric motor for rotationally driving the auxiliary pinion, the speed reducer, etc. is limited, and the degree of freedom in arrangement is extremely small.

The main purpose of the present invention is to solve the problems of the conventional rack-and-pinion type electric power steering device as described above, and will be explained below with reference to the embodiments shown in the accompanying drawings.

In Fig. 1, 1 is a steering wheel;
2 is the steering shaft, 3 is the intermediate shaft,
4 is a pinion, and when the steering handle 1 is rotated, the pinion 4 rotates via the steering shaft 2 and the intermediate shaft 3, and a rack shaft 5 is supported in the steering gear box 6 so as to be slidable in the axial direction. Steering is performed by sliding in the axial direction.

7 is an electric motor, 8 is a speed reducer, and 9 is a pinion. The electric motor 7 is controlled by a signal from a torque sensor 10 that detects the torque of the steering shaft 2. For example, the steering wheel 1 When the motor is rotated to the right, the torque sensor 10 detects the rotational torque and rotates the electric motor 7 to the right, which causes the pinion 9 to rotate to the right via the reducer 8 and slide the rack shaft 5 in the steering direction. The manual operation force from the steering handle 1 side is assisted by the input from the electric motor 7 side, thereby reducing the manual operation force.

In the rack-and-pinion type electric power steering device as described above, in the present invention, the rack shaft is connected to the manual side pinion 4 as shown in FIG.
The manual rack tooth 5b that meshes with the electric motor side pinion 9 and the auxiliary rack tooth 5c that meshes with the electric motor side pinion 9 are provided independently and separately at different angle positions on the rack material 5a. It is something to do.

In the embodiment shown in FIG. 2, the auxiliary rack tooth 5c is provided at a position angularly displaced by 180 degrees with respect to the manual rack tooth 5b, but as shown in FIG. The position may be angularly displaced by 90 degrees, and the angularly displaced position of 5c relative to 5b may be arbitrarily selected.

Furthermore, the tooth pitch of the auxiliary rack teeth 5c may be changed from that of the manual rack teeth 5b to have different gear ratios to reduce the load on the electric motor 7. Either one or both of the rack teeth 5b and 5c may have a variable ratio to reduce the load during large steering turns.

As described above, the present invention adopts a configuration in which the rack teeth that mesh with the manual side pinion and the auxiliary rack teeth that mesh with the pinion on the electric motor side are formed independently and separately at different angle positions on the rack material. This makes it possible to freely select the direction and position of the electric motor side pinion assembly, greatly improving the degree of freedom in the arrangement of the power assist assembly consisting of the electric motor, reducer, pinion, etc. The constraints on the design of the vehicle body to which the motor is to be installed are significantly relaxed, and as mentioned above, it is easy to configure both the rack teeth with different tooth pitches to reduce the load on the electric motor. , one or both of the electric motors can be configured to have a variable ratio as required, and many excellent effects can be brought about.

[Brief explanation of drawings]

The attached drawings show an embodiment of the present invention. Fig. 1 is a perspective view of the overall appearance, and Figs. 2 and 3 are front views showing the engaged state of the rack shaft and pinion, each showing an embodiment of the invention. It is. 1... Steering handle, 2... Steering shaft, 4... Manual side pinion, 5...
...Rack shaft, 5a...Rack material, 5b...Manual rack teeth, 5c...Auxiliary rack teeth, 6...
Steering gear box, 7... electric motor,
8...Reducer, 9...Electric motor side pinion, 1
0...Torque sensor.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A manual system that steers by rotating a steering handle, and a system that is rotatably driven in accordance with the steering torque of the manual system and steers in the steering direction of the manual system. In a rack-and-pinion electric power steering device equipped with an electric motor that assists power, a rack shaft that is slidably supported in the steering gear box in the axial direction is connected to a manual rack tooth that meshes with a manual system pinion. An electric power steering device characterized by having a structure in which auxiliary rack teeth that mesh with an electric motor side pinion rotated by a motor are formed separately at different angle positions on a rack material. (2) The electric power steering device according to claim 1, wherein the manual rack teeth and the auxiliary rack teeth have different tooth pitches. (3) The electric motor according to claim 1 or 2 of the utility model registration claim, wherein either or both of the manual rack teeth and the auxiliary rack teeth are configured with a variable ratio. Power steering device.