CN-116648400-B - Steering device

Abstract

The steering device has an input shaft (9) connected to a steering wheel, and an intermediate shaft (11) connected to the input shaft (9) and outputting a rotational force input from the input shaft (9) to the transmission mechanism side. The intermediate shaft (11) is connected to the electric motor (2) via a speed reducer (19) composed of a worm gear in which a worm shaft (21) and a worm wheel (22) are meshed. The electric motor (2) applies a rotational force to the intermediate shaft (11) via a speed reducer (19).

Inventors

• Saito Guanghui
• NAKAMURA SHINJI

Assignees

• 克诺尔转向系统日本有限公司

Dates

Publication Date

20260508

Application Date

20211126

Priority Date

20201222

Claims (13)

1. 1. A steering device is provided with: a steering shaft to which a rotational force from a steering wheel is input; A transmission mechanism that transmits rotation of the steering shaft to a steering wheel; a power cylinder having a piston provided in the transmission mechanism and a pair of fluid chambers defined by the piston, the power cylinder being capable of applying a steering force for steering the steering wheel; A rotary valve capable of selectively supplying the working fluid to the pair of fluid chambers according to the rotation of the steering shaft, and An electric motor capable of applying a rotational force to the steering shaft via a speed reducer constituted by meshing of a worm shaft and a worm wheel, The steering shaft has a first shaft connected to the steering wheel and a second shaft connected to the first shaft, and the second shaft outputs a rotational force input from the first shaft to the transmission mechanism side, and is fastened with the worm wheel and forms a part of the rotary valve.
2. 2. The steering device according to claim 1, The first shaft and the second shaft are coupled to each other via a torsion bar.
3. 3. The steering device according to claim 2, The second shaft is formed of a metallic material, The speed reducer includes the worm wheel having a cylindrical metal core formed of a metal material, The metal core is press-fitted to the outer peripheral portion of the second shaft.
4. 4. A steering device according to claim 3, The second shaft has a receiving recess formed in an axial end face on the first shaft side, and a female screw portion engaged with a male screw portion of a press-fitting device for press-fitting the metal core portion is provided on an inner peripheral surface of the receiving recess.
5. 5. A steering device according to claim 3, The second shaft has an annular recess formed in an outer peripheral surface thereof, and a protrusion of a press-fitting device for press-fitting the metal core is fitted into the annular recess.
6. 6. The steering device according to claim 2, The second shaft is formed of a metallic material, The speed reducer includes the worm wheel having a cylindrical metal core formed of a metal material, The metal core is fastened to the outer peripheral portion of the second shaft by heat or cold caulking.
7. 7. The steering device according to claim 1, The first shaft and the second shaft are connected to each other via a torsion bar and a tubular connecting shaft provided around the torsion bar.
8. 8. The steering device according to claim 7, The second shaft is formed of a metallic material, The speed reducer includes the worm wheel having a cylindrical metal core formed of a metal material, The metal core is press-fitted to the outer peripheral portion of the second shaft.
9. 9. The steering device according to claim 8, The second shaft has a receiving recess formed in an axial end face on the first shaft side, and a female screw portion engaged with a male screw portion of a press-fitting device for press-fitting the metal core portion is provided on an inner peripheral surface of the receiving recess.
10. 10. The steering device according to claim 8, The second shaft has an annular recess formed in an outer peripheral surface thereof, and a protrusion of a press-fitting device for press-fitting the metal core is fitted into the annular recess.
11. 11. The steering device according to claim 7, The second shaft is formed of a metallic material, The speed reducer includes the worm wheel having a cylindrical metal core formed of a metal material, The metal core is fastened to the outer peripheral portion of the second shaft by heat or cold caulking.
12. 12. The steering device according to claim 7, The second shaft has a receiving recess formed in an axial end face on the first shaft side, and the connecting shaft is inserted into the receiving recess.
13. 13. The steering device according to claim 7, The steering device further includes a housing that accommodates the steering shaft, a ball bearing that is provided to the housing and rotatably supports the connecting shaft, a retainer ring that is provided to an inner peripheral surface of the housing and supports an outer ring of the ball bearing, and a retainer ring that presses the outer ring of the ball bearing against the retainer ring.

Description

Steering device Technical Field The present invention relates to a steering device. Background As a steering device, for example, a steering device described in patent document 1 below is known. In the steering device described in patent document 1, the steering shaft includes a first shaft connected to the steering wheel, a second shaft connected to the first shaft and outputting a rotational force input from the first shaft to the transmission mechanism side, and a connecting shaft rotatably accommodating the first shaft and connected to the second shaft via a spline portion. The connection shaft is connected to the electric motor via a speed reducer. Prior art literature Patent literature Patent document 1 Japanese patent application No. 2019-026915 Disclosure of Invention Technical problem to be solved by the invention In the steering device described in patent document 1, since the connecting shaft and the second shaft are connected via the spline portion, looseness associated with the connection occurs between the connecting shaft and the second shaft. When the electric motor applies a rotational force to the connection shaft via the speed reducer, the second shaft may rotate with deterioration of responsiveness due to the loosening. The present invention has been made in view of the conventional circumstances, and an object thereof is to provide a steering device capable of improving the responsiveness of a rotational force to a second shaft. Technical scheme for solving technical problems In the present invention, as one aspect thereof, the electric motor applies the rotational force to the second shaft via the decelerator. ADVANTAGEOUS EFFECTS OF INVENTION According to the present invention, the responsiveness of the rotational force with respect to the second shaft can be improved. Drawings Fig. 1 is a perspective view of a steering device according to a first embodiment. Fig. 2 is a longitudinal sectional view of the steering device of the first embodiment taken along the line A-A of fig. 1. Fig. 3 is an enlarged partial cross-sectional view of the steering device of fig. 2. Fig. 4 is a cross-sectional view of the first press-in device of the first embodiment. Fig. 5 is a process diagram showing a process of fixing the shaft portion to be fixed according to the first embodiment. Fig. 6 is a process diagram showing a press-fitting process of the worm wheel according to the first embodiment. Fig. 7 is an explanatory view of a first embodiment of the worm wheel in a state of being press-fitted into the intermediate shaft. Fig. 8 is a cross-sectional view of a second press-in device of a second embodiment. Fig. 9 is a process diagram showing a process of fixing the shaft portion to be fixed according to the second embodiment. Fig. 10 is a process diagram showing a press-fitting process according to the second embodiment. Fig. 11 is an explanatory diagram of a second embodiment of the worm wheel in a state of being press-fitted into the intermediate shaft. Fig. 12 is a cross-sectional view of a fixed shaft portion of a third press-fitting device according to a third embodiment. Fig. 13 is a process diagram showing a process of fixing the shaft portion to be fixed according to the third embodiment. Fig. 14 is a process diagram showing a press-fitting process according to the third embodiment. Fig. 15 is an explanatory view of a third embodiment of the worm wheel in a state of being press-fitted into the intermediate shaft. Fig. 16 is a process diagram showing a press-fitting process of the worm wheel according to the fourth embodiment. Fig. 17 is a partial longitudinal sectional view of the steering device of the fifth embodiment. Fig. 18 is a partial longitudinal sectional view of a steering device of the sixth embodiment. Detailed Description First embodiment (Structure of steering device) Fig. 1 is a perspective view of a steering device according to a first embodiment, fig. 2 is a longitudinal sectional view of the steering device according to the first embodiment taken along a line A-A of fig. 1, and fig. 3 is an enlarged partial sectional view of the steering device of fig. 2. In fig. 1 to 3, for convenience of explanation, the longitudinal direction of the steering shaft 7 is defined as the "axial direction", the direction orthogonal to the steering shaft 7 is defined as the "radial direction", and the direction around the steering shaft 7 is defined as the "circumferential direction". The description will be given with respect to the axial direction, in which one side (upper side in the figures) connected to a steering wheel (not shown) is referred to as "one end", and one side (lower side in the figures) connected to the piston 28 is referred to as "the other end". In fig. 2 and 3, the electric motor 2, the EPS controller 3, the worm shaft 21, and the like are shown by broken lines. The steering device is an integral steering device used for a large vehicle or the like, and mainly includes a s