JP2006082612A - Steering shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an axially two-split type steering shaft capable of reducing the sense of incongruity of a driver during the steering operation by effectively regulating the bend of both shafts. <P>SOLUTION: A main shaft 21 of the steering system has the axially two-split type structure in which a main shaft 21a is inserted in one end of a main shaft 21b, and the main shaft is fixed at the axial center rotatably in the axial direction by bearings 22a-22c at both ends opposite to a joining part of the main shafts 21a, 21b and three parts in a vicinity of the joining part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a structure of a steering system, and more particularly to a steering shaft that transmits rotation of a steering wheel to a steering gear box.

  A steering shaft is disposed between the steering wheel and the steering gear box in order to transmit the rotation of the steering wheel disposed in the driver's seat to the steering wheel.

A structure is known in which the steering shaft is divided into two in the axial direction, and when the load is applied in the axial direction due to an impact at the time of collision, the steering shaft is separated and contracted or bent to alleviate the impact on the occupant (see Patent Document 1). . In such a steering shaft, it is necessary that the divided shafts have a structure that reliably separates even a small axial load and that reliably transmits a rotational force. In the technique of Patent Document 1, the opposing end portions of both shafts are coaxially opposed to each other with a predetermined axial gap, and a holding member that restricts the bending of both shafts is arranged on the outer periphery of the opposing end portions. A connecting member that connects the agent and both shafts and releases the connection with a predetermined axial load is provided.
Japanese Patent Laid-Open No. 7-40842

  By the way, during steering, a secondary couple is generated on the main shaft by a reaction force from the road surface, and a bending stress is applied to the main shaft by the secondary couple. In the two-divided shaft as described above, a stress is applied to the divided portion by this bending stress, and the deformation actually occurs. Even if this deformation is slight, the driver may feel uncomfortable during steering by being enlarged by the steering wheel. In the technique of Patent Document 1, this deformation cannot be sufficiently suppressed, and if it is attempted to suppress this, it becomes difficult to reliably separate the shaft with a small axial load.

  Accordingly, an object of the present invention is to provide an axially-divided two-part steering shaft in which the bending of both shafts is effectively regulated to reduce the uncomfortable feeling felt by the driver during steering.

  In order to solve the above-described problems, a steering shaft according to the present invention divides a part of a steering shaft that transmits rotation of a steering wheel to a steering gear box into two parts so as to be separable, and one end of both divided shafts. Is inserted into the other end, and one is held slidably in the axial direction with respect to the other, and the support is arranged at three locations near both ends of the divided shafts and near the joint of both shafts. By means, the shaft centers of both shafts are fixed and supported rotatably.

  That is, bearings and the like are arranged in the vicinity of the coupling portion of both shafts and at three positions on both ends to support the bifurcated steering shaft so as to be split. As a result, at least one shaft is rotatably supported at both ends by bearings or the like.

  Of the supporting means, the supporting means arranged at the center preferably supports the central end of the shaft arranged outside. In this case, both ends of the shaft arranged outside are supported not only rotatably by bearings and the like, but both ends are also supported via the shaft arranged outside.

  According to the present invention, at least one end of each of the two divided shafts is rotatably supported while the center of the shaft is fixed by a bearing or the like, so that the shaft can be effectively deformed by the secondary couple generated on the shaft. Can be suppressed. For this reason, it is possible to suppress the transmission of the secondary couple to the steering wheel, and to reduce the uncomfortable feeling felt during steering.

  In particular, it is preferable to support the central side end portion of the shaft disposed on the outer side, because both shafts can be supported at both ends, so that deformation of the shaft can be further effectively suppressed.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same reference numerals are given to the same components in the drawings as much as possible, and duplicate descriptions are omitted.

  FIG. 1 is a configuration diagram of a steering system including a steering shaft according to the present invention. FIG. 2 is a configuration diagram of a column assembly including the first embodiment of the steering shaft according to the present invention, and FIG. 3 is a configuration diagram of the steering shaft in FIG. The steering system includes a steering wheel 1, a steering column portion 2, a steering gear 3, and tie rods 4a and 4b.

  The steering wheel 1 is disposed in the vehicle interior so as to be rotatable around its axis center, and receives a steering operation input from the driver. The steering column portion 2 is a mechanism for transmitting the rotational input of the steering wheel 1 to the steering gear 3 and includes a steering main tube 20 incorporating a steering main shaft 21 and two connecting shafts 28 and 29. The main tube 20 is supported on the vehicle body by two brackets 26 and 27. A column cover 25 is disposed on the steering tube 1 side of the main tube 20.

  The steering gear 3 is, for example, a rack and pinion type gear mechanism, and is a mechanism that switches the rotational movement of the connecting shaft 29 to the horizontal movement of the tie rods 4a and 4b. The tie rods 4a and 4b turn steered wheels (not shown) by this horizontal movement.

  In the main tube 20, a steering main shaft 21 is supported by three bearings 22a to 22c so as to be rotatable around its axis center (see FIGS. 2 and 3). The main shaft 21 is an axially divided two shaft including a first main shaft 21 a connected to the steering wheel 1 and a second main shaft 21 b connected to the connecting shaft 28. The second main shaft 21b is formed in a cylindrical shape thicker than the first main shaft 21a, and the distal end of the first main shaft 21a on the connection shaft 28 side is disposed on the steering wheel 1 side of the second main shaft 21b. Has been inserted. The rotation of the steering wheel 1 is transmitted from the first main shaft 21a to the second main shaft 21b by friction.

  The bearing 22a is arranged to support the steering wheel 1 side of the first main shaft 21a, and the bearing 22b supports the connecting shaft 28 side of the first main shaft 21a, that is, the second main shaft 21b side. The bearing 22c is arranged to support the connecting shaft 28 side of the second main shaft 21b.

  In this steering system, when a force in the compression direction is applied to the main shaft 21 at the time of a vehicle collision or the like, the first main shaft 21a is inserted into the second main shaft 21b, thereby the main shaft 21. The whole length is compressed. At this time, the brackets 26 and 27 are disengaged and the positional relationship with the connecting shafts 28 and 29 is changed, so that the driver is protected by suppressing the protrusion of the steering wheel 1 and thus the main shaft 21 into the vehicle interior. To do.

  The main shaft 21 has such a divided configuration, and the main shaft 21 needs to be compressed even with a relatively small compressive force in order to ensure safety. As a result, in a situation where the split-type main shaft 21 is not fixed, twisting, bending, and bending are likely to occur compared to a main shaft that is integrally configured as a whole. And since the deformation | transformation which generate | occur | produced in the junction part of the main shaft 21a and the main shaft 21b is expanded as vibration of a wheel in the steering wheel 1 part connected to the opposite side of the main shaft 21a, and is transmitted to a driver | operator, Even a slight deformation of about several tens of μm per se may cause the driver to feel uncomfortable at the time of steering.

  In the present embodiment, a bearing 22b is disposed in the vicinity of the joint, and the vicinity of the end of the main shaft 21a connected to the steering wheel 1 on the side opposite to the steering wheel 1 is supported. By using the bearing 22b, the rotation around the axial center of the main shaft 21a can be freely made and the axial center can be fixed with high precision. Therefore, the opposite ends of the main shafts 21a and 21b can be fixed. The shaft center of the main shaft 21 can be fixed with high accuracy over almost the entire length together with the bearings 22a and 22c arranged in the section. As a result, deformations such as twisting, bending, and bending of the main shaft 21 can be suppressed, and the driver's uncomfortable feeling of steering can be reduced or eliminated.

  FIG. 4 is a configuration diagram of a column assembly including a second embodiment of the steering shaft according to the present invention, and FIG. 5 is a configuration diagram of the steering shaft in FIG.

  In this embodiment, the basic configuration is the same as that of the first embodiment shown in FIGS. 1 to 3, and only the arrangement position of the bearing 22b arranged in the middle is different. Specifically, the bearing 22b is disposed so as to support the vicinity of the end of the main shaft 21b on the connection shaft 28 side near the end of the main shaft 21a at the joint between the main shaft 21a and the main shaft 21b.

  In this embodiment, since the shaft centers of both the main shafts 21a and 21b are fixed at the joint, the main shafts 21a and 21b are arranged together with the bearings 22a and 22c disposed at the opposite ends of the main shafts 21a and 21b. The shaft center of the shaft 21 can be fixed with high accuracy over substantially the entire length thereof. As a result, deformations such as twisting, bending, and bending of the main shaft 21 can be suppressed, and the driver's uncomfortable feeling of steering can be reduced or eliminated.

  The present invention can also be suitably applied to a steering system in which a hydraulic or electric power steering device is arranged. Further, the type of the steering system is not limited to the type shown in FIG. 1, but can be applied to the type of steering system of each company.

1 is a configuration diagram of a steering system including a steering shaft according to the present invention. It is a lineblock diagram of a column assembly containing a 1st embodiment of a steering shaft concerning the present invention. FIG. 3 is a configuration diagram of a steering shaft in FIG. 2. It is a block diagram of the column assembly containing 2nd Embodiment of the steering shaft concerning this invention. It is a block diagram of the steering shaft in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Steering wheel, 2 ... Steering column part, 3 ... Steering gear, 4a, 4b ... Tie rod, 20 ... Steering main tube, 21, 21a, 21b ... Steering main shaft, 22a-22c ... Bearing, 25 ... Column cover, 26 ... brackets, 27, 28 ... connecting shafts.

Claims (2)

A part of the steering shaft that transmits the rotation of the steering wheel to the steering gear box is divided in two so as to be separable, and one end of each of the divided shafts is inserted into the other end, and one is relative to the other In the steering shaft that is slidable in the axial direction,
Steering shaft characterized in that the shaft centers of both shafts are fixed and rotatably supported by supporting means arranged at three locations near both ends of both divided shafts and near the joint portion of both shafts. .   The steering shaft according to claim 1, wherein the support means arranged at the center of the support means supports a center side end portion of the shaft arranged outside.

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