JP2008120250A - Vehicle steering telescopic shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle steering telescopic shaft, smoothly slid by reducing sliding resistance of a male shaft and a female shaft axially moving relatively to each other, and preventing rattling feeling of a steering wheel. <P>SOLUTION: The vehicle steering telescopic shaft 20 is constituted of mutually spline-fitted male spline shaft 21 and a female spline shaft 22. Resin coating 23 is formed to a surface of the spline of the male spline shaft 21. The mutually spline-fitted male spline shaft 21 and a female spline shaft 22 are heated in a heating furnace at an ambient temperature in the furnace of around 150 °C, and the temperature state is kept for around one hour. Then, by air-cooling to a room temperature, annealing treatment of the resin coating 23 formed on the surface of the spline of the male spline shaft 21 is performed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a telescopic shaft for vehicle steering that is incorporated in a steering shaft of a vehicle and has a male shaft and a female shaft that are non-rotatably and slidably fitted.

  The telescopic shaft of the steering mechanism portion of the automobile is required to absorb the axial displacement generated when the automobile travels and to transmit the displacement and vibration on the steering wheel. Further, in order to obtain an optimum position for the driver to drive the automobile, a function of moving the position of the steering wheel in the axial direction and adjusting the position is required. In any of these cases, the telescopic shaft is required to reduce the rattling noise, reduce the rattling on the steering wheel, and reduce the sliding resistance during the sliding operation in the axial direction. .

For this reason, for example, in Patent Document 1, a synthetic resin thin film is formed on a fitting surface of at least one of a male shaft and a female shaft that are capable of transmitting torque and are relatively movable in the axial direction. Thus, the play of the male shaft and the female shaft is prevented, and the sliding resistance when both slide is attempted to be kept low. Here, the synthetic resin thin film of Patent Document 1 is obtained by applying an organic solvent in which small particles such as molybdenum disulfide (MoS ₂ ) are dispersed and mixed in a petroleum-based binder by spraying or dipping and drying by heating. It is formed with.
JP 2000-9148 A

  However, as in Patent Document 1, the technique of forming a synthetic resin thin film by applying an organic solvent to the mating surface tends to vary the thickness of the thin film. There is not enough effect to reduce the sliding resistance when the male shaft and the female shaft move relative to each other in the axial direction, and to reduce the backlash of the telescopic shaft and the steering wheel. .

  Therefore, the present invention has been made paying attention to the unsolved problems of the above-described conventional example, and can slide smoothly by reducing the sliding resistance of the male shaft and the female shaft that move relative to each other in the axial direction. In addition, an object of the present invention is to provide a vehicle steering telescopic shaft that can prevent the steering wheel from feeling loose.

  To achieve the above object, the telescopic shaft for vehicle steering according to claim 1 is incorporated in a steering shaft of a vehicle, and a male shaft and a female shaft are fitted so as to be able to transmit torque and move relative to each other in the axial direction. A telescopic shaft for vehicle steering formed by forming a resin coating on a fitting surface of one of the male shaft and the female shaft, wherein the resin coating is annealed. It is.

  The telescopic shaft for vehicle steering according to claim 2 is incorporated in a steering shaft of a vehicle, and a male shaft and a female shaft are fitted so as to be able to transmit torque and move relative to each other in the axial direction. In a telescopic shaft for vehicle steering formed by forming a resin film on one fitting surface of a female shaft, the resin film is annealed in a state where the male shaft and the female shaft are fitted. The telescopic shaft for vehicle steering.

  Furthermore, the telescopic shaft for vehicle steering according to claim 3 is the telescopic shaft for vehicle steering according to claim 1 or 2, wherein the annealing treatment is applied to one of the fitting surfaces of the male shaft and the female shaft. The formed resin film was heated and held in a heating furnace having a furnace atmosphere temperature of 100 ° C. to 200 ° C. for a heating time of about 30 minutes to 60 minutes, and then air-cooled to room temperature.

  According to the vehicle steering telescopic shaft of the present invention, since the resin coating formed on the fitting surface of either the male shaft or the female shaft is annealed, the resin coating has a uniform thickness. For this reason, the sliding resistance when the male shaft and the female shaft move relative to each other in the axial direction can be reduced and the sliding can be smoothly performed, and the rattling of the steering wheel connected to the end of the telescopic shaft can be prevented. be able to.

  In addition, the resin film formed on the mating surface of either the male shaft or the female shaft is subjected to annealing treatment to remove internal residual strain, so that cracks are unlikely to occur and the telescopic shaft is slid for a long time. However, since peeling of the film or the like is suppressed, sufficient durability can be obtained.

Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described in detail with reference to the drawings.
FIG. 1 is a side view showing an embodiment in which a vehicle steering telescopic shaft according to the present invention is applied to a steering mechanism of an automobile.
The steering mechanism portion 15 of the present embodiment includes a steering column 4 attached to a member 1 on the vehicle body side via an upper bracket 2 and a lower bracket 3, and a steering shaft 5 rotatably supported by the steering column 4. The steering wheel 6 mounted on the upper end of the steering shaft 5, the intermediate shaft 8 connected to the lower end of the steering shaft 5 via the cardan shaft joint 7, and the cardan shaft joint 9 connected to the intermediate shaft 8 A pinion shaft 10 connected through a pinion, a steering rack shaft 11 connected to the pinion shaft 10, and a steering rack that supports the steering rack shaft 11 and is fixed to another frame 12 of the vehicle body via an elastic body 13. It is comprised with the supporting member 14. FIG.

The intermediate shaft 8 is formed by fitting a male shaft 8a and a female shaft 8b. The intermediate shaft 8 absorbs axial displacement generated when the automobile travels, and the steering shaft 6 Therefore, the performance that does not transmit the displacement and vibration is required.
In such a performance, the vehicle body has a sub-frame structure, and the member 1 that fixes the upper portion of the steering mechanism 15 and the frame 12 to which the steering rack support member 14 is fixed are separated from each other. This is required in the case of a structure in which the support member 14 is fastened and fixed to the frame 12 via an elastic body 13 such as rubber.

As another case, when the intermediate shaft 8 is fastened to the pinion shaft 10 at the position of the cardan shaft joint 9, the operator temporarily contracts the telescopic shaft and then expands and contracts to fit the pinion shaft 10 and fasten it. Function is needed.
Further, the steering shaft 5 at the upper part of the steering mechanism 15 is also configured by fitting a male shaft 5a and a female shaft 5b. Such a steering shaft 5 is optimal for a driver to drive an automobile. In order to secure a driving posture, the position of the steering wheel 6 is moved in the axial direction, and a telescopic function for adjusting the position is required, so a function of extending and contracting in the axial direction is required.

Here, the vehicle steering telescopic shaft according to the present invention is applied to the steering shaft 5 and the intermediate shaft 8. In the following description, when the steering shaft 5 and the intermediate shaft 8 are collectively described, they are simply abbreviated as the telescopic shaft.
In all the cases described above, the telescopic shaft has a reduced rattling noise at the fitting portion of the male shaft and the female shaft, a backlash feeling on the steering wheel 6, and a sliding at the time of axial sliding. It is required to reduce dynamic resistance.

FIG. 2 is a cross-sectional view showing the configuration of the telescopic shaft 20 of the first embodiment according to the present embodiment.
The telescopic shaft 20 of this embodiment includes a male spline shaft 21 (a male shaft 5a of the steering shaft 5 and a male shaft 8a of the intermediate shaft 8) and a female spline shaft 22 (the female shaft 5b of the steering shaft 5 And a female shaft 5b) of the intermediate shaft 8.
The male spline shaft 21 is a solid cylindrical member made of steel, and a spline having a pitch circle diameter of 18 mm and a spline module of 1.0 is formed on the outer peripheral surface thereof. A resin film 23 made of a synthetic resin (nylon or the like) having a thickness of about 0.25 mm is formed on the surface of the spline.

The female spline shaft 22 is a steel hollow cylindrical member having an outer diameter of 25 mm. A spline is formed on the inner peripheral surface of the female spline shaft 22, and no resin film is formed on the surface of the spline.
In this embodiment, the male spline shaft 21 and the female spline shaft 22 that are spline-fitted with each other are heated in a heating furnace having a furnace atmosphere temperature of about 150 ° C., and the temperature state is maintained for about one hour. Thereafter, the resin film 23 formed on the surface of the spline of the male spline shaft 21 is annealed by air cooling to room temperature. The annealing conditions may be set such that the furnace atmosphere temperature in the heating furnace is 100 ° C. to 200 ° C., and the heating time is about 30 minutes to 60 minutes.

When annealing is performed under such conditions, the resin film 23 provided on the surface of the spline of the male spline shaft 21 has a uniform thickness while removing the internal residual strain.
Therefore, in the present embodiment, since the resin coating 23 formed on the surface of the spline of the male spline shaft 21 is made uniform by performing the annealing treatment, the processing that the resin coating becomes too thick and the thickness is uniformly adjusted is performed. There is no need for the resin coating to become too thin, so that there is no gap between the female spline shaft 22 and the spline surface, and there is no increase in interference, and the male spline shaft 21 and the female spline shaft 22 are axial. The sliding resistance at the time of relative movement can be reduced and the telescopic shaft 20 can be smoothly slid. In addition, the backlash of the steering wheel 6 can be prevented.

In addition, the resin film 23 formed on the surface of the spline of the male spline shaft 21 is subjected to an annealing process so that residual strain is removed, so that cracks are unlikely to occur, and the telescopic shaft 20 is actually incorporated and slid for a long time. Also, since peeling of the film is suppressed, sufficient durability can be obtained.
The fitting shape of the telescopic shaft 20 is not limited to the spline fitting as shown in FIG. 2, for example, a substantially rectangular fitting as shown in FIG. 3, a substantially triangular shape as shown in FIG. As long as it is possible to transmit torque between the two shafts, such as fitting, and slide in the axial direction, any irregular fitting may be used.

Next, FIG. 5 is a cross-sectional view showing the configuration of the telescopic shaft 24 of the second embodiment according to this embodiment. In addition, the same code | symbol is attached | subjected to the same component as steel shown in FIG. 2, and the description is abbreviate | omitted.
The telescopic shaft 24 of the present embodiment does not form a resin film on the surface of the spline formed on the outer peripheral surface of the male spline shaft 21, but on the surface of the spline formed on the inner peripheral surface of the female spline shaft 22. A resin film 25 made of a synthetic resin (nylon or the like) having a thickness of about 0.25 mm is formed.

  Also in this embodiment, the male spline shaft 21 and the female spline shaft 22 that are spline-fitted with each other are heated in a heating furnace having a furnace atmosphere temperature of about 150 ° C., and the temperature state is maintained for about one hour. Thereafter, the resin film 25 formed on the surface of the spline of the female spline shaft 22 is annealed by air cooling to room temperature. As in the first embodiment, the annealing conditions may be set such that the furnace atmosphere temperature in the heating furnace is 100 ° C. to 200 ° C., and the heating time is about 30 minutes to 60 minutes.

When annealing is performed under such conditions, the resin film 25 provided on the surface of the spline of the female spline shaft 22 has a uniform thickness while removing internal residual strain.
Therefore, in the present embodiment, since the resin coating 25 formed on the surface of the spline of the female spline shaft 22 is made uniform by performing the annealing process, the processing becomes such that the resin coating becomes too thick and the thickness is uniformly adjusted. There is no need for the resin coating to become too thin, so that there is no gap between the female spline shaft 22 and the spline surface, and there is no increase in interference, and the male spline shaft 21 and the female spline shaft 22 are axial. The sliding resistance at the time of relative movement can be reduced and the telescopic shaft 24 can be smoothly slid. In addition, the backlash of the steering wheel 6 can be prevented.

Further, the resin film 25 formed on the surface of the spline of the female spline shaft 22 is subjected to an annealing process, so that residual strain is removed, so that cracks are hardly generated, and the telescopic shaft 24 is actually incorporated and slid for a long time. Also, since peeling of the film is suppressed, sufficient durability can be obtained.
In the present embodiment, the fitting shape of the telescopic shaft 24 is not limited to the spline fitting, for example, the substantially square fitting shown in FIG. 3, the substantially triangular fitting shown in FIG. As long as torque transmission between both shafts is possible and sliding in the axial direction is possible, any irregular fitting may be used.

In the first and second embodiments, the resin coating is annealed in a state where the male spline shaft 21 and the female spline shaft 24 are spline-fitted, but the male spline shaft 21 and the female spline shaft 24 are applied. The spline fitting may not be performed, and only the male spline shaft 21 or the female spline shaft 24 on which the resin film is formed may be annealed.
Furthermore, the telescopic shaft shown in the first embodiment and the second embodiment is not applied to the steering mechanism portion of the automobile shown in FIG. 1, but includes, for example, a power assist mechanism in which a motor is incorporated in a steering column. Even if it is applied to a power steering device, the same effect can be obtained.

1 is a schematic side view of a steering mechanism part of an automobile to which a telescopic shaft for vehicle steering according to an embodiment of the present invention is applied. It is a cross-sectional view showing the telescopic shaft for vehicle steering according to the first embodiment of the present invention. It is a cross-sectional view showing the telescopic shaft for vehicle steering in another fitting state. FIG. 4 is a cross-sectional view showing a vehicle steering telescopic shaft in a fitting state different from FIG. 3. It is a cross-sectional view showing a telescopic shaft for vehicle steering according to a second embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Member, 2 ... Upper bracket, 3 ... Lower bracket, 4 ... Steering column, 5 ... Steering shaft, 5a ... Male shaft, 5b ... Female shaft, 6 ... Steering wheel, 7 ... Cardan shaft coupling, 8 ... Intermediate shaft, 8a ... male shaft, 8b ... female shaft, 9 ... cardan shaft joint, 10 ... pinion shaft, 11 ... steering rack shaft, 12 ... frame, 13 ... elastic body, 14 ... steering rack support member, 15 ... steering mechanism section, 20 ... telescopic shaft, 21 ... male spline shaft, 22 ... female spline shaft, 23 ... resin coating, 24 ... telescopic shaft, 25 ... resin coating

Claims (3)

Built into the steering shaft of a vehicle, the male shaft and female shaft are fitted so that torque can be transmitted and moved relative to each other in the axial direction, and a resin film is formed on the fitting surface of either the male shaft or the female shaft In the vehicle steering telescopic shaft,
A telescopic shaft for vehicle steering, wherein the resin coating is annealed. Built into the steering shaft of a vehicle, the male shaft and female shaft are fitted so that torque can be transmitted and moved relative to each other in the axial direction, and a resin film is formed on the fitting surface of either the male shaft or the female shaft In the vehicle steering telescopic shaft,
A telescopic shaft for vehicle steering, wherein the resin coating is annealed with the male shaft and the female shaft fitted.   The resin coating formed on the mating surface of one of the male shaft and the female shaft is subjected to the annealing treatment in a heating furnace with a furnace atmosphere temperature of 100 ° C. to 200 ° C. for about 30 minutes to 60 minutes. The telescopic shaft for vehicle steering according to claim 1 or 2, characterized in that the heating and holding is performed for a heating time of, and then air cooling is performed to room temperature.

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