JP2003287054A - Universal coupling for steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a universal coupling for a steering device which prevents intrusion of dust to a bearing part to an actually convenient degree without providing a cover to cover the whole coupling and reduces bending torque. <P>SOLUTION: A plurality of needles 10 and steel made bearing cups 9 are interposed in this order between an outside rolling surface 61 of a trunnion shaft 6 and an inner surface 41 of a bearing hole 4, and a bearing part 5 is formed of them. The bearing cup 9 is a cup shaped body furnished with a cylindrical wall part 92, a bottom part 91 provided on one of it and an opened inward flange 9a on the other, and the bottom part 91 prevents intrusion of dust to the inside of the bearing part 5 from outside. A soft foaming body ring 8 of a soft foaming body is a ring shape to fit on the trunnion shaft 6 with no clearance on its base part 81 and prevents intrusion of dust by making contact with the outside surface of the inward flange 9a of the bearing cup 9 with no clearance by light pressure. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a universal joint of a vehicle steering system, and more particularly to a sealing used in the universal joint.

[0002]

2. Description of the Related Art In a vehicle steering system, the rotation of a steering wheel is transmitted to a lower shaft connected to a steering mechanism through an upper shaft and an intermediate shaft. A universal joint mechanism is configured between the lower end of the upper shaft and the upper end of the intermediate shaft, and between the lower end of the intermediate shaft and the upper end of the lower shaft. Rotation can be transmitted between them.

FIG. 1 is an explanatory view for explaining an example of a conventional universal joint mechanism. At the end portions of the first shaft 101 and the second shaft 102 that face each other, a yoke (first
A yoke 1 and a second yoke 2) are provided, and each yoke has a pair of bifurcated yoke legs 11. A bearing hole 4 is provided in each yoke leg 11, and the bearing hole 4
The shaft portions (trunnion shafts 6) on the opposite sides of the cross-shaped trunnion cloth 3 are supported by. As described above, in the universal joint mechanism, by interposing the trunnion cross 3, the rotation can be transmitted between one shaft and the other shaft even if they are not parallel to each other. The trunnion cross and trunnion shaft are also called spider and spider shaft, respectively.

A total roller type bearing mechanism is constructed by interposing a large number of needles 10 between the bearing hole 4 of each yoke leg (1 and 2) and the trunnion shaft 6 to keep the friction resistance low. There is. The needle 10 is housed inside the bottomed bearing cup 9 and is held by an inward flange 9a at the end of the bearing cup 9 so as not to come out. Each trunnion shaft 6 is provided with a ring-shaped seal member 7, which prevents dust from entering from the outside by sliding contact between the outer surface of the inward flange 9a and the two lips.

In the universal joint mechanism, when torque is transmitted between two tilted shafts, friction generated here causes a load greater than that required on the output side shaft as compared with the case where the shaft is coaxial. A large torque must be applied to the input shaft. This increase in torque is called bending torque, which adversely affects the steering feeling of the steering wheel. Therefore, it is required to reduce the bending torque as much as possible.

Attempts have been made to reduce this bending torque by not providing a seal member on the universal joint in the vehicle compartment, as shown by the dotted circle in FIG. Even in the passenger compartment, dust adhering to the passenger's shoes or the like and brought into the passenger compartment may enter the bearing portion of the universal joint and cause a trouble. For this reason, a steering device using such a universal joint is provided with a large cover that covers the universal joint and the intermediate shaft, or even another universal joint. For this reason, not only is the vehicle compartment narrowed, but also a cover and its installation work are required, which causes an increase in production cost.

[0007]

DISCLOSURE OF THE INVENTION The present invention prevents the entry of dust into the bearing portion to the extent that it does not hinder practical use without providing a cover for covering the whole as described above, and moreover, the bending torque described above is almost eliminated. An object of the present invention is to provide a universal joint for a steering device having a sealing function that does not increase.

[0008]

The above problems can be solved by the following means. That is, the solving means of the first invention is a first yoke having a pair of legs that are substantially parallel to each other, a pair of first bearing holes formed so that their central axes are common to the legs of the first yoke, respectively. A second yoke having a pair of parallel legs, a second pair of bearing holes formed with a common central axis on each of the legs of the second yoke, and four trunnion shafts orthogonal to each other in a cross shape. Trunnion cross, outer rolling surfaces formed on each of the trunnion shafts, a tubular wall portion for fitting into each of the first bearing hole pair and the second bearing hole pair, and one of the tubular wall portions Bearing cups having a bottom portion provided on the inner surface of the bearing cup and an inward flange having the other opening open, an inner rolling surface formed on the inner surface of the bearing cup, and a plurality of rolling elements for rolling on the inner rolling surface. The needle, and Between each inner respective outer rolling surface and the bearing hole pairs down axis, the needle, the universal joint for a steering device assembled by interposing the bearing cup,
A universal joint for a steering device, characterized in that each of the trunnion shafts is provided with a soft foam ring that fits without a gap, and an end surface of the ring is in contact with the outer surface of the inward flange with a light surface pressure. Is.

According to a second aspect of the invention, in the universal joint for a steering device of the first aspect of the invention, a bottomed hole coaxial with the trunnion shaft is formed at each end of the trunnion shaft. In the bottomed hole, a thrust piece made of synthetic resin that comes into contact with the bottom portion of the bearing cup is housed, which is a universal joint for a steering device.

According to a third aspect of the present invention, in the steering device universal joint according to the first aspect of the present invention, the bottom portion of the bearing cup is formed with a projection for contacting the end face of the trunnion shaft. It is a universal joint for a steering device characterized by the above.

According to a fourth aspect of the present invention, in the universal joint for a steering device according to the first to third aspects of the invention, the soft foam ring is a soft foam made of polyurethane resin. It is a universal joint for a steering device.

According to a fifth aspect of the invention, the universal joint according to any one of the first to fourth aspects is provided at the end of the intermediate shaft connecting the two universal joints in the vehicle compartment. It is a steering device characterized by the above.

According to a sixth aspect of the present invention, there is provided a vehicle interior, in which both ends of an intermediate shaft connecting two universal joints are
A steering device comprising the universal joint according to any one of the first to fourth aspects of the invention.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION First Embodiment Hereinafter, a universal joint for a steering device of the present invention will be described with reference to the drawings. FIG. 3 is a partial cross-sectional view of the universal joint according to the first embodiment. 4 and 5 are partially enlarged views of the inside of the dotted line circle in FIG. 3, in which FIG. 4 is in the middle of assembling the bearing portion 5, and FIG. 5 is after being assembled.

As shown in FIG. 3, the universal joint 100 includes:
The first shaft 101 and the second shaft 102 and a pair of yokes (first yoke 1 and second yoke 2) at their ends.
Is provided, and the two shafts are coupled by interposing the trunnion cross 3.

The first yoke 1 and the second yoke 2 are each formed of a pair of yoke legs 11 which are bifurcated and are substantially parallel to each other.
A bearing hole 4 is provided in each of the yoke legs 11 with the central axis thereof being common. The trunnion cloth 3 includes four trunnion shafts 6 extending from the main body in a cross shape and orthogonal to each other. A universal joint is formed by fitting each trunnion shaft 6 into the bearing hole 4 and connecting the first shaft 101 and the second shaft 102.

As shown in FIGS. 4 and 5, a plurality of needles 10 and a steel bearing cup 9 are provided between the outer rolling surface 61 of the outer surface of the trunnion shaft 6 and the inner surface 41 of the bearing hole 4. Are interposed in this order, and thus the bearing portion 5 is formed. The bearing cup 9 is a cup-shaped body having a tubular wall portion 92, a bottom portion 91 provided on one side, and an inward flange 9a open on the other side.
The numeral 1 prevents foreign matter from entering the bearing portion 5 from the outside.

The outer rolling surface 61 of the trunnion shaft 6 and the inner rolling surface 921 of the tubular wall portion 92 are rolling surfaces on which the needle 10 rolls. The soft foam ring 8 is fitted into the trunnion shaft 6 at the base portion 81 without a gap, and is in contact with the outer surface of the inward flange 9a of the bearing cup 9 with a light surface pressure. In FIG. 4, since the bearing part 5 is in the process of being assembled, the bearing cup 9, the needle 1
0 is in the upper position in FIG. 4, and as shown in FIG. 5, the inward flange 9a of the bearing cup 9 is previously attached to the trunnion shaft 6 in advance.
The soft foam ring 8 fitted to the is pressed into the soft foam ring 8 to be assembled. However, the amount of deformation of the soft foam ring 8 is sufficiently large. What you can do this is
This is because the soft foam ring 8 is sufficiently soft and does not require so much force (contact pressure) to be largely deformed.

A thrust piece 83 made of synthetic resin is fitted in a bottomed hole 84 provided at the center of the end face of the trunnion shaft 6, and since the top portion thereof is a frusto-conical shape, the bearing cup 9 has a small area. It is in contact with the bottom 91 (Fig. 5).

As the first shaft 101 rotates, the rotation is transmitted to the yoke leg 11, the trunnion shaft 6, the other trunnion shaft 6, and the other yoke leg 11, so that the second shaft 102 is rotated.
Rotates. When the shaft rotates, the trunnion shaft 6 is supported by the yoke leg 11, so
It makes a reciprocating rotation within an angle range of several tens of degrees.

The soft foam ring 8 enhances the foaming degree,
It is a synthetic resin foam that suppresses elasticity to a low level (made soft), and is not limited, but a polyurethane resin soft foam is preferable. In the conventional rubber contact-type seal, it is necessary to apply a large contact pressure in order to absorb an assembly error or a product error and improve the adhesion performance. Therefore, the contact pressure increases the frictional resistance, and a large bending torque appears during reciprocal rotation.

In the present embodiment, the soft foam ring 8
Comes into contact with the bearing cup 9 fixed to the yoke leg 11, but at this time, it can be largely deformed with a small force, and has a high tolerance with respect to assembly error and manufacturing error of the soft foam ring, and the gap can be obtained with a light pressure. Since the contact can be made without contact, the frictional force can be made extremely small. Therefore, the bending torque is significantly reduced, and the steering feeling of the steering wheel is not deteriorated.

The soft foam ring 8 can also be manufactured very inexpensively. The soft foam ring 8 not only prevents dust from entering from the outside, but also prevents low-viscosity components of the internal lubricant (grease etc.) from leaking to the outside, so that dust may adhere to the leaked components. It is possible to prevent the vehicle interior from being contaminated without providing a dust cover as in the conventional case. Further, since the above-mentioned components are retained in the foam cavity and are supplied from here to the rolling portion in the opposite direction, the foam is also useful for maintaining the lubricating performance. Further, since the bearing portion 5 is closed at the bottom portion 91 of the bearing cup 9, the dust does not enter the inside of the bearing portion 5 from here. For this reason, there is substantially no obstacle that dust may enter and damage the bearing as much as it is used in the vehicle interior.

At the time of assembly, the thrust piece 83 is inserted into the bottomed hole 84, and the bottom portion 91 abuts the frustro-conical top portion to slightly compress it. As a result, the trunnion cloth 3 is prevented from moving in the direction of the trunnion shaft 6, and a tapping sound is prevented from being generated. Since the contact diameter at the top of the thrust piece 83 is small, and the fact that it easily fits in with synthetic resin overlaps, the friction moment becomes very small, so that the bending torque hardly increases.

Second Embodiment FIG. 6 is a partial sectional view of a universal joint according to a second embodiment. The difference from the universal joint of the first embodiment is that the thrust piece 83 is not provided, and instead, the projection 93 is provided at the center of the bottom portion 91 of the bearing cup 9. The protrusion 93 having a trapezoidal cross section is formed by plastically deforming the material of the bottom portion 91 inward, and after assembly, contacts the center of the end face of the trunnion shaft 6 and presses it with an appropriate force.

Similar to the thrust piece 83 of the first embodiment, the protrusion 93 prevents the trunnion cloth 3 from moving in the direction of the trunnion shaft 6 and prevents the generation of hammering sound. The contact diameter at the top of the thrust piece 83 is small, and the friction moment is very small, and this contact hardly increases the bending torque. Since the soft foam ring 8 has a high tolerance for an assembly error and a manufacturing error of the soft foam ring and can contact with each other with a light pressure without a gap, the frictional force can be made extremely small, and Therefore, the bending torque is remarkably reduced, the steering feeling of the steering wheel is not deteriorated, and the soft foam ring 8 can be manufactured at a very low cost, as in the first embodiment. The other points are the same as those in the first embodiment, though redundant description will be omitted.

Third Embodiment A third embodiment, a fourth embodiment, and FIGS. 7 and 8 describe a steering device using the universal joint 100 and its location.

In the steering apparatus, a steering wheel 201, a steering shaft 202, a first universal joint, an intermediate shaft 203, a second universal joint, a pinion shaft 204 and a pinion 205 are connected in this order. The pinion 205 meshes with a rack (not shown).

A normal automobile is divided by a dashboard 206 into an engine room and a vehicle compartment. In the third embodiment, the two universal joints are both arranged in the vehicle compartment, and the universal joint 100 including the soft foam ring 8 described above is used for the two universal joints. Since the interior of the vehicle is less dusty than the engine room, the universal joint 100 of the present invention can be used. Since the bending torque is much smaller than that of the conventional universal joint, the steering feeling can be improved. Further, since it is not necessary to provide a cover for covering the whole unlike the conventional case, the vehicle interior can be widely used. Further, this cover and its installation work become unnecessary, and the production cost can be reduced.

Fourth Embodiment In the fourth embodiment, a dashboard 206 is provided on the intermediate shaft 203, which is divided into an engine room and a vehicle compartment. In the passenger compartment, the universal joint of the present invention is used, and in the engine room with much dust, the universal joint provided with the conventional sealing member is used. Since the interior of the vehicle is less dusty than the engine room, the universal joint 100 of the present invention can be used. Since the bending torque can be made extremely small as compared with the case where the conventional universal joint is also used in the vehicle compartment, the steering feeling can be improved. Further, since it is not necessary to provide a cover for covering the whole unlike the conventional case, the vehicle interior can be widely used. Further, this cover and its installation work become unnecessary, and the production cost can be reduced.

[0031]

As described above, by arranging the universal joint of the present invention in the passenger compartment, and in the engine room with much dust, the universal joint provided with the conventional seal member is arranged. The universal joint of the present invention functions satisfactorily in a vehicle compartment that has less dust than a room. In the present invention, since the bending torque is not so large as in the conventional universal joint, the steering feeling can be improved, and further, it is not necessary to provide the cover for covering the whole unlike the conventional art, so The effect is that it can be widely used. Further, this cover and its installation work are unnecessary, and the production cost can be reduced.

Further, the soft foam ring used in the present invention can be manufactured and obtained at a very low cost, and the end face and the outer face of the inwardly facing flange can be brought into contact with each other with a light surface pressure, which is the reason why. While sealing can be increased,
In addition, there is an effect that tolerance for assembly error and manufacturing error of the soft foam ring is high.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for explaining an example of a conventional universal joint mechanism.

FIG. 2 is an explanatory view of a conventional universal joint in which a seal member is not provided in the universal joint in the vehicle compartment.

FIG. 3 is a partial cross-sectional view of the universal joint according to the first embodiment.

FIG. 4 is a partially enlarged view in which the inside of a dotted line circle in FIG. 3 is enlarged and is a diagram in the middle of assembly.

FIG. 5 is a partially enlarged view of the inside of a dotted circle in FIG. 3, which is an assembled view.

FIG. 6 is a partial sectional view of a universal joint according to a second embodiment.

FIG. 7 is an explanatory view for explaining a steering device using the universal joint 100 and a location of the steering device according to the third embodiment.

FIG. 8 is a fourth embodiment, and is an explanatory view for explaining a steering device using the universal joint 100 and a location thereof.

[Explanation of symbols]

1st York 10 needles 100 universal joint 101 first shaft 102 Second shaft 11 York legs 2 second yoke 201 steering wheel 202 steering shaft 203 Intermediate shaft 204 pinion shaft 205 pinion 206 dashboard 3 trunnion cross 4 bearing holes 41 Inside 5 Bearing part 6 trunnion shaft 61 Outer rolling surface 7 Seal member 8 Soft foam ring 81 base 83 Thrust piece 84 Bottomed hole 9 Bearing cup 91 bottom 92 Cylindrical wall 921 Inner rolling surface 93 protrusion 9a Inward flange

Claims (6)

[Claims] 1. A first yoke having a pair of substantially parallel legs, a pair of first bearing holes formed with a common central axis for each of the legs of the first yoke, and a pair of substantially parallel legs. A second yoke having; a second bearing hole pair formed with a common central axis for each leg of the second yoke; a trunnion cross having four trunnion shafts orthogonal to each other in a cross shape; Outer rolling surfaces formed on each of the shafts, a tubular wall portion for fitting into each of the first bearing hole pair and the second bearing hole pair, and a bottom portion provided on one of the tubular wall portions. , Four bearing cups each having an inwardly facing flange that is open on the other side, an inner rolling surface formed on the inner surface of the bearing cup, and a plurality of needles for rolling on the inner rolling surface. And each of the above trunnion shafts Between the outer rolling surface and the respective inside of the bearing hole pairs, the needle,
In a universal joint for a steering device assembled with the bearing cup interposed, a soft foam ring that fits tightly into each of the trunnion shafts is provided, and its end face is light on the outer face of the inward flange. A universal joint for a steering device, which is in contact with the surface pressure. 2. The universal joint for a steering device according to claim 1, wherein each trunnion shaft has a bottomed hole coaxial with the trunnion shaft, formed in each end of the trunnion shaft. Is a universal joint for a steering device, in which a thrust piece made of synthetic resin that comes into contact with the bottom portion of the bearing cup is housed. 3. The steering system universal joint according to claim 1, wherein the bottom portion of the bearing cup is formed with a protrusion for contacting an end surface of the trunnion shaft. Universal joint for equipment. 4. The steering device universal joint according to claim 1, wherein the soft foam ring is a soft foam made of polyurethane resin. Universal joint. 5. A steering characterized in that a universal joint according to any one of claims 1 to 4 is provided at an end portion of an intermediate shaft connecting two universal joints in a vehicle compartment. apparatus. 6. The universal joint according to any one of claims 1 to 4 is provided at both ends of an intermediate shaft connecting two universal joints in a vehicle interior. Steering device.