JPH0821454A - Bearing cap structure of universal joint - Google Patents

Abstract

PURPOSE:To provide a bearing cap structure which can avert the exfoliation of the coating applied on the outer peripheral surface of the cylinder part in the projection state from a spider installation hole, when the bearing cap installation completes. CONSTITUTION:The top end part 8a of a spider 8 is coaxially inserted freely into each spider installation hole 9 of yokes 6 and 7, and a bearing cap 11 into which a needle bearing 10 is installed is interposed between the spider installation hole 9 and the top end part 8a of the spider 8, and the bearing cap 11 is supported in a rotatable manner. The bearing cap 11 is constituted of a cylindrical part 12 and a bottom plate part 13 covering the opened port part at one end of the cylindrical body part 12. The cylindrical body part 12 is divided to a large diameter part 12a on the bottom plate side and a small diameter part 12b on the opened port part side at the other end, having the stage difference 12c as boundary.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a universal joint used for a lower joint portion and a front and rear end portion of a propeller shaft in a steering device, and more particularly to a structure of a bearing cap used for the universal joint. Is.

[0002]

2. Description of the Related Art The tips of spiders (cruciform shafts) forming the shaft of a universal joint are mounted on a yoke via bearings so that the shafts can rotate. Conventionally, as shown in FIG. 6, the mounting structure is such that the tip portion of the spider 31 is loosely fitted in the spider mounting hole 32 formed in the yoke 30, and the outer peripheral surface of the tip portion of the spider 31 and the spider mounting hole 32 are arranged. Between the inner peripheral surface of the needle bearing 3
The cylindrical portion 34a of the bearing cap 34 having the number 3 is interposed and configured.

The bearing cap 34 has a cylindrical portion 34a having an outer diameter capable of being fitted to the inner peripheral surface of the spider mounting hole 32.
And a bottom plate portion 34b capable of facing one end surface of the spider 31 by closing one open end of the cylindrical portion 34a. Further, an inward flange 34c is formed at the other end opening end of the cylindrical portion 34a of the bearing cap 34, and between the inward flange 34c and the annular projection 31a provided with the spider 31, The seal member 35 is provided to prevent water and dust from entering the bearing cap 34.

[0004]

Assembling of the bearing cap 34 with respect to the spider mounting hole 32
It is carried out by being press-fitted from the outside of the yoke 30 (the upper side in FIG. 4). During this press-fitting, the entire outer peripheral surface of the cylindrical portion 34a of the bearing cap 34 is rubbed against the inner peripheral surface of the spider mounting hole 32. At this time, the outer peripheral surface of the cylindrical portion 34a is coated for the purpose of rust prevention, but as described above, a part of the coating applied to the cylindrical portion 34a is rubbed by the spider mounting hole 32. It will come off.

When the assembly is completed, the opening end side (the portion indicated by A in FIG. 4) of the cylindrical portion 34a is open to the outside air, so that the coating may be peeled off depending on the usage environment of the universal joint. There is a risk that rust will be generated from the portion and the rust will push up the seal member 35. The above seal member 3
When the push-up of No. 5 occurs, water penetrates into the bearing cap 34 through the gap and rusts the tip end portion of the spider 31 and the bearing, which causes the shaft rotation of the spider 31 to become unsmooth and the operation of the universal joint to be reluctant. . this is,
For example, when it is used for a lower joint of a steering wheel, it leads to deterioration of steering feeling.

For this reason, conventionally, after the bearing cap 34 is assembled, it is necessary to paint again, and there is a problem that productivity is poor. Further, when the bearing cap 34 is press-fitted into the spider mounting hole 32, as shown in FIG. 7, the bearing cap 34 may be deformed so as to be relatively reduced in diameter toward the opening end side. This deformation causes an inclination of the contact surface of the inward flange 34c of the bearing cap 34 with the seal member 35, which affects the contact accuracy, and the contact between the needle bearing 33 and the outer peripheral surface of the tip end of the spider 31. There is a risk that the spider 31 is unbalanced and is caught in the rotation of the spider 31 (increase in rotation torque).

The present invention has been made in view of the above problems, and it is possible to prevent the coating applied to the outer peripheral surface of the cylindrical portion protruding from the spider mounting hole from being peeled off when the bearing cap is completely assembled. The purpose is to provide a simple bearing cap structure.

[0008]

In order to achieve the above object, a bearing cap structure of a universal joint according to the present invention is fitted in a spider mounting hole formed in a yoke, and a spider is internally mounted via a bearing. In the bearing cap into which the tip portion of is inserted, the diameter of the outer periphery of the outer peripheral surface of the cylindrical portion of the bearing cap that is not in contact with the inner peripheral surface of the spider mounting hole is equal to the outer periphery of the portion that contacts the inner peripheral surface of the spider mounting hole. The feature is that it is formed to have a relatively smaller diameter than the diameter.

At this time, as described in claim 2, at the boundary between the outer peripheral surface of the cylindrical portion which is not in contact with the inner peripheral surface of the spider mounting hole and the portion which is in contact with the inner peripheral surface of the spider mounting hole. It is characterized by forming a step. Alternatively, as described in claim 3, a taper shape in which the diameter of the outer circumference of the outer peripheral surface of the cylindrical portion that is not in contact with the inner peripheral surface of the spider mounting hole is reduced toward the opening end of the cylindrical portion. Is characterized by

[0010]

When the bearing cap is press-fitted into the spider mounting hole by making the outer diameter of the portion of the outer peripheral surface of the cylindrical portion that does not come into contact with the spider mounting hole relatively small, the portion with the small diameter is inside the spider mounting hole. Does not make sliding contact with the peripheral surface. Therefore, it is possible to prevent the coating applied to the small-diameter portion from peeling off.

Further, since the cylindrical portion position of the portion having a small diameter at the time of press-fitting does not receive the load from the inner peripheral surface of the spider mounting hole,
The deformation of the tubular portion, which is reduced in diameter toward the open end portion when press-fitting, is reduced. Further, when a step is provided as described in claim 2, in addition to the function of the invention described in claim 1, the following function is provided.

When the bearing cap is press-fitted, it is press-fitted to a position where the stepped position is aligned with the opening end face of the spider mounting hole. This serves as a guide for the alignment of the bearing cap in the spider mounting hole.
Further, as set forth in claim 3, when the outer surface of the portion which does not come into contact with the spider mounting hole is tapered,
In addition to the operation of the invention described in the first claim, the following operation is provided.

The wall thickness of the portion that does not come into contact with the spider mounting hole can be set thicker than in the case of the stepped shape. Therefore, as compared with the bearing cap structure according to the first aspect of the present invention, the rigidity of the portion that does not contact the spider mounting hole can be set higher. Further, by tapering the diameter so that the diameter decreases toward the opening end, the sealing member interposed between the outer peripheral surface of the spider and the opening end of the cylindrical body is expanded by the tapered surface. Abut.
Therefore, the crimping force between the seal member and the bearing cap is improved.

[0014]

An embodiment of the present invention will be described with reference to the drawings.
The present embodiment is an example in which the universal joint according to the present invention is used for a steering lower joint. That is, as shown in FIG. 3, a steering shaft 2 having a steering wheel 1 attached to an upper end thereof penetrates through a steering column 3 and extends forward and downward in the vehicle front-rear direction. The lower end of the steering shaft 2 is swingably connected to a steering gear 5 via a lower joint 4 which is a universal joint.

In the lower joint 4, as shown in FIG. 2, the yoke 6 attached to the lower end portion of the steering shaft 2 and the yoke 7 attached to the steering gear 5 side are 90 degrees out of phase with each other. The yokes 6 and 7 are arranged so as to face each other in a state of being connected to each other through a cross-shaped spider 8. As shown in FIG. 1, the connecting structure of the spider 8 and the yokes 6 and 7 has a cross shape in the spider mounting holes 9 formed in the bifurcated legs 6a and 7a of the yokes 6 and 7, respectively. Each tip 8 of the spider 8
It is carried out by attaching a to the shaft so as to be rotatable.

That is, the spider mounting holes 9 of the yokes 6 and 7
The tip end 8a of the spider 8 is coaxially loosely inserted in the bearing cap 1 for accommodating the needle bearing 10 between the spider mounting hole 9 and the tip end 8a of the spider 8.
1 is rotatably supported by being interposed. The bearing cap 11 includes an annular cylindrical body portion 12 and a bottom plate portion 13 that covers one end opening of the cylindrical body portion 12. The tip portion 8a of the spider 8 is coaxially inserted into the cap of the bearing cap 11 so that the inner surface of the bottom plate portion 13 can face the tip surface of the spider 8.

The outer peripheral shape of the cylindrical body 12 is such that the thickness of the other end opening side is thin so that a step 12c is formed midway in the axial direction, so that the outer diameter of the other end opening side. Has a relatively small diameter, whereby the cylindrical body portion 12 is divided into a large diameter portion 12a on the bottom plate side and a small diameter portion 12b on the other end opening side with the step 12c as a boundary. However, no step is formed on the inner peripheral surface of the cylindrical body portion 12.

A plurality of needle bearings 10 are arranged on the inner peripheral surface of the cylindrical body 12 so as to be lined up in the circumferential direction.
Is provided, and rotatably supports the outer peripheral surface of the tip portion 8a of the spider 8 via the needle bearing 10. Further, an inward flange 14 extending toward the outer peripheral surface of the spider 8 is formed on the entire circumference of the other end opening of the tubular portion 12, and the inward flange 14 and the annular flange provided on the outer peripheral surface of the spider 8 are formed. An annular seal member 15 is provided between the protrusions 8b to prevent water and dust from entering the bearing cap 11.

The bearing cap 11 having the above-mentioned structure is assembled in advance by setting the tip 8a of the spider 8 having the seal member 15 loosely inserted into the spider mounting holes 9 of the yokes 6, 7. After that, the bearing cap 11 in which the needle bearing 10 is arranged on the inner peripheral side,
From the other end opening side, press fit into the spider mounting hole 9 and assemble.

In the press-fitting, the position of the step 12c of the cylindrical portion 12 of the bearing cap 11 is set at the spider mounting hole 9
Press-fit until it becomes the same position as the opening end face of. As a result, the tip portion 8a of each spider 8 passes through the needle bearing 10 and the bearing cap 11 and the yoke 6,
It is rotatably supported by the shaft 7.

When the bearing cap 11 is press-fitted, the small-diameter portion 12b of the tubular portion 12 has a small diameter, so that the small-diameter portion 12b does not come into sliding contact with the inner peripheral surface of the spider mounting hole 9, so that the small-diameter portion 12b. It is possible to prevent the paint applied to the tape from coming off. This small diameter portion 12b is
Although it is open to the outside air, it prevents the paint from peeling off during assembly as described above.Therefore, there is no need to paint again to prevent rust as in the past, and productivity is improved. good.

Further, the bearing cap 11 of the present embodiment.
Then, since the load from the spider mounting hole 9 is not applied to the small diameter portion 12b during the press-fitting, it is possible to avoid the narrowing toward the other end opening side as shown in FIG. As a result, the contact surface accuracy of the inward flange 14 with respect to the seal member 15 is improved. Further, as shown in FIG. 7, when the spider 8 is unbalanced, the load is unevenly distributed between the needle bearing 10 and the outer periphery of the tip 8a of the spider 8.
This is one of the causes of catching (rotation torque increase) when the shaft rotates, but this can also be avoided.

The lower joint 4 has a function of transmitting the torque input from the steering wheel 1 via the steering shaft 2 to the steering gear 5 while changing the transmission direction. At this time, the increase in the rotation torque of the spider 8 deteriorates the steering feeling, but by using the bearing cap 11 of the present embodiment, the deterioration of the steering feeling can be avoided.

Further, as described above, the step 1 is formed on the cylindrical portion 12.
When the step 2c is formed, the step 12c serves as a guide for the alignment of the bearing cap 11 when press-fitting, and the alignment of the bearing cap 11 when press-fitting is facilitated.
Next, the bearing cap structure of the second embodiment will be described with reference to FIG. However, the same reference numerals are used for the same members as in the first embodiment.

The basic part of the bearing cap of the second embodiment is composed of an annular cylindrical body portion 12 and a bottom plate portion 13 that covers the one end opening of the cylindrical body portion 12. The tip portion 8a of the spider 8 is coaxially inserted into the bearing cap 11 so that the inner surface of the bottom plate portion 13 can face the tip surface of the spider 8. The outer peripheral shape of the cylindrical body portion 12 is tapered from the middle in the axial direction toward the other end opening portion, and the thickness is reduced toward the other end opening portion side,
The outer diameter of the other end opening side is relatively small. As a result, the cylindrical body portion 12 is divided into a large diameter portion 12a on the bottom plate side and a small diameter portion 12b on the other end opening side with a middle position in the axial direction as a boundary. However, the inner peripheral surface of the cylindrical body portion 12 is not processed into a tapered shape.

A plurality of needle bearings 10 are arranged on the inner peripheral surface of the cylindrical portion 12 so as to be arranged along the circumferential direction.
Is provided, and rotatably supports the outer peripheral surface of the tip portion 8a of the spider 8 via the needle bearing 10. Further, an inward flange 14 extending toward the outer peripheral surface of the spider 8 is formed on the entire circumference of the other end opening of the tubular portion 12, and the inward flange 14 and the annular flange provided on the outer peripheral surface of the spider 8 are formed. An annular seal member 15 is arranged between the protrusions to prevent water and dust from entering the bearing cap 11.

A foot portion 15a on the outer peripheral side of the seal member 15
Contacts the tapered surface 20 from the outside, and the tapered surface 2
The small diameter portion 1 so that the diameter is expanded toward the tip portion 8a by 0.
It is relatively pushed outward from 2b. As a result, the pressure bonding force between the seal member 15 and the outer surface of the small diameter portion 12b is improved, and the sealing performance is set high.

To mount the bearing cap 11 having the above structure, the tip portion 8a of the spider 8 on which the seal member 15 is disposed is previously attached to the spider mounting holes 9 of the yokes 6a and 7a.
The bearing cap 11 having the needle bearing 10 disposed on the inner peripheral side after being set to the state of being loosely inserted in the
Is press-fitted into the spider mounting hole 9 from the other end opening side,
Assemble.

The press-fitting is carried out until the starting position of the tapered surface of the cylindrical body 1212 of the bearing cap 11 becomes the same position as the opening end surface of the spider mounting hole 9. As a result, the tip portion 8a of each spider 8 is axially rotatably supported by the yokes 6a and 7a via the needle bearing 10 and the bearing cap 11.

When the bearing cap 11 is press-fitted, the small-diameter portion 12b of the tubular portion 12 has a small diameter, so that it does not come into sliding contact with the inner peripheral surface of the spider mounting hole 9, so the small-diameter portion 12b. It is possible to prevent the paint applied to the tape from coming off. This small diameter portion 12b is
Although it is open to the outside air, it prevents the paint from peeling off during assembly as described above.Therefore, there is no need to paint again to prevent rust as in the past, and productivity is improved. good.

The bearing cap 11 of this embodiment is also used.
Then, since the load from the spider mounting hole 9 is not applied to the small diameter portion 12b during the press-fitting, it is possible to avoid the narrowing toward the other end opening side as shown in FIG. As a result, the contact surface accuracy of the inward flange 14 with respect to the foot portion 15b on the inner peripheral side of the seal member 15 is improved. Also,
As shown in FIG. 7, the unevenness of the load occurs between the needle bearing 10 and the outer periphery of the tip portion 8a of the spider 8 to prevent the trapping (increase of the rotation torque) during the axial rotation of the spider 8. This contributes to this, but this can be avoided.

The lower joint has a function of transmitting the torque input from the steering wheel via the steering shaft to the steering gear while changing the transmission direction. At this time, the increase in the rotation torque of the spider 8 deteriorates the steering feeling, but by using the bearing cap 11 of the present embodiment, the deterioration of the steering feeling can be avoided.

Further, as described above, when the small diameter portion 12b is formed in the cylindrical portion 12, the open position of the tapered surface formed on the outer surface of the small diameter portion 12b serves as a guide for the positioning of the bearing cap 11 during press fitting. Positioning when the bearing cap 11 is press-fitted becomes easy. Further, in the second embodiment, the outer diameter of the cylindrical body at the opening at the other end is set to the above-mentioned first
When the diameter is set to be the same as that of the embodiment, the thickness of the small diameter portion 12b is set to be thicker than that in the case where the step portion of the first embodiment is formed, and the rigidity of the position of the small diameter portion 12b is made larger than that of the first embodiment. You can earn.

In the above embodiment, the tapered surface 20 of the small-diameter portion 12b is formed in a straight line in the axial direction toward the other end opening side, but the other end opening portion is drawn while drawing a curve protruding outward. You may process so that the diameter may be reduced toward. In this case, the thickness of the small diameter portion 12b can be increased. The point is that the outer diameter of the small diameter portion 12b may be processed to be smaller than the outer diameter of the large diameter portion 12a.

In the above embodiment, the entire outer periphery of the portion (small diameter portion 12b) which does not come into contact with the spider mounting hole 9 is tapered, but as shown in FIG. 5, the portion which abuts on the foot portion 15a of the seal member 15. Only the shape may be tapered 21. In all of the above embodiments, the universal joint used for the lower joint of the steering wheel is described. However, even if it is adopted for the bearing cap of the universal joint used for the joint portion of the propeller shaft or the like, the above-described action and effect can be obtained. Obtainable.

[0036]

As described above, in the bearing cap structure of the universal joint according to the present invention, the coating of the portion of the cylindrical portion which is opened to the outside air when the assembling is completed is prevented from peeling off at the time of assembling, and the productivity is improved. Is improved. Further, since the cylindrical portion position of the small diameter portion does not receive a load from the inner peripheral surface of the spider mounting hole during press fitting, deformation of the cylindrical portion that reduces in diameter toward the opening end side in press fitting is reduced. Therefore, it is possible to avoid the deterioration of the contact accuracy with the seal member and the increase of the rotation torque of the spider.

Further, by adopting the structure described in claim 2, it becomes easy to perform the positioning when the bearing cap is press-fitted. Further, by adopting the configuration described in claim 3, the rigidity of the portion that does not contact the spider mounting hole can be set higher than that of the bearing cap structure described in claim 2.

Further, the pressing force with the sealing member is improved, and the sealing performance is improved.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a bearing cap structure of an embodiment according to the present invention.

FIG. 2 is a side view showing a universal joint according to an embodiment of the present invention.

FIG. 3 is a view showing a position where the universal joint of the embodiment according to the present invention is used.

FIG. 4 is a side sectional view showing a bearing cap structure of a second embodiment according to the present invention.

FIG. 5 is a side sectional view showing another example of the bearing cap structure of the second embodiment according to the present invention.

FIG. 6 is a side sectional view showing a conventional bearing cap structure.

FIG. 7 is a view showing a deformed state of the bearing cap.

[Explanation of symbols]

 6,7 Yoke 8 Spider 9 Spider mounting hole 10 Needle bearing 11 Bearing cap 12 Cylindrical portion 12a Large diameter portion 12b Small diameter portion 12c Step 13 Bottom plate portion 14 Inward flange 15 Seal member 15a Outer side foot portion 20 Tapered surface

Claims (3)

[Claims] 1. A bearing cap fitted in a spider mounting hole formed in a yoke and having a tip end of the spider fitted therein via a bearing, wherein the spider is provided on the outer peripheral surface of the cylindrical portion of the bearing cap. A bearing cap structure for a universal joint, characterized in that the outer diameter of the portion not contacting the inner peripheral surface of the mounting hole is formed to be relatively smaller than the outer diameter of the portion contacting the inner peripheral surface of the spider mounting hole. 2. A step is formed on a boundary between a portion of the outer peripheral surface of the cylindrical portion that is not in contact with the inner peripheral surface of the spider mounting hole and a portion that is in contact with the inner peripheral surface of the spider mounting hole. Bearing cap structure of the universal joint described in. 3. The outer peripheral surface of the outer peripheral surface of the outer peripheral surface of the cylindrical portion, which is not in contact with the inner peripheral surface of the spider mounting hole, has a taper shape in which the diameter is reduced toward the opening end of the cylindrical portion. A bearing cap structure for a universal joint according to claim 1 or 2.