JP2007278444A - Cross shaft coupling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cross shaft coupling capable of preventing damage to a shaft and a rolling element in mounting a cup bearing, having the rolling element inside, to the shaft of a cross shaft. <P>SOLUTION: A protective cover 7 is mounted to the tip of the shaft 3 of the cross shaft 1. The protective cover 7 is made of resin and covers the outer peripheral edge 4a of the end face 4 of the shaft 3, and its outer peripheral surface is flush with the outer peripheral surface of the shaft 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cross joint.

For example, in an automobile steering device, in order to connect a column shaft and a steering shaft, a cross shaft having four shaft portions protruding in four directions from the side peripheral surface of the body portion and the outer peripheral surface of the shaft portion roll. A cross joint having a plurality of rolling elements and a cylindrical bearing cup with a bottom that is externally fitted to the plurality of rolling elements is used. A pair of opposing yokes are provided at the end of each shaft, and the shaft portion of the cross shaft is inserted into a bearing hole formed in each yoke via a bearing cup in which a plurality of rolling elements are arranged on the inner periphery. It is supported so as to be rotatable about its axis.
When the transmission torque is increased in such a joint structure having a cross shaft joint, slippage occurs in the rolling elements, and rattling due to poor torque transmission occurs or pulsation occurs.
In order to solve this problem, as shown in Patent Document 1, for example, a structure in which an interference fit between the rolling elements and the shaft portion of the cross shaft is conventionally proposed.

International Publication No. WO2003-064877

As shown in FIG. 10, the assembly of the joint structure including the cross shaft joint of Patent Document 1 is performed with the shaft portion 44 of the cross shaft 43 inserted in the bearing hole 42 of the yoke 41. From outside in the axial direction, a bearing cup 46 having a plurality of rolling elements 45 arranged on the inner periphery is brought close to the shaft portion 44, and the rolling element 45 in the bearing cup 46 is pivoted while being pressed into the bearing hole 42. This is done by fitting from the tip of the portion 44. As a result, the diameter of the bearing cup 46 is reduced to bring the rolling element 45 and the shaft portion 44 into pressure contact, that is, the interference fit state.
However, when the rolling element 45 in the bearing cup 46 is fitted on the shaft portion 44, the bearing cup 46 is reduced in diameter by press-fitting into the bearing hole 42. Further, the corner portion 47 of the end surface of the shaft portion 44 is in strong contact with the outer peripheral surface of the shaft portion 44 serving as a rolling surface, and the rolling element 45 may be scratched or deformed. In particular, at the initial stage of fitting when the rolling element 45 comes into contact with the tip of the shaft part 44, the contact surface pressure between the rolling element 45 and the shaft part 44 is large, so that the tip of the shaft part 44 is easily damaged. As described above, when the rolling surface of the shaft portion 44 or the rolling element 45 is damaged, the performance and durability of the joint structure may be deteriorated.

  Therefore, the present invention has been made in view of the above problems, and can prevent the shaft portion and the rolling element from being damaged when the bearing cup having the rolling element on the inner periphery is attached to the shaft portion of the cross shaft. An object is to provide a cross joint.

  In order to achieve the above object, the cross shaft joint of the present invention includes a cross shaft having four shaft portions protruding in four directions from the side peripheral surface of the body portion, and a plurality of rolling elements that roll on the outer peripheral surface of the shaft portion. And a bottomed cylindrical bearing cup that is externally fitted to the plurality of rolling elements, wherein the rolling part is maintained in an interference fit with the shaft part. A resin cover that covers at least the outer peripheral edge portion of the end surface of the shaft and has an outer peripheral surface flush with the outer peripheral surface of the shaft portion is attached to the tip of the shaft portion.

According to this configuration, when a plurality of rolling elements are arranged on the inner periphery of the bearing cup, and when this is fitted from the front end side of the shaft portion of the cross shaft, the rolling elements first come into contact with the resin cover, This cover can prevent damage to the tip of the shaft and the rolling element. In particular, since the rolling element is in an interference fit state with respect to the shaft portion in the assembled state, when the bearing cup in which the rolling elements are arranged along the inner periphery is attached to the shaft portion, the rolling element is an end surface of the shaft portion. Although the outer peripheral edge is covered with the cover, damage to the end face of the shaft and the rolling element can be prevented. Further, the outer peripheral surface of the cover and the outer peripheral surface of the shaft Therefore, once the rolling element in the bearing cup is externally fitted to the cover, the rolling element can be smoothly fitted to the shaft portion only by moving the bearing cup in the axial direction.

Moreover, in this cross joint, it is preferable that the cover has a contact surface that contacts an inner bottom surface of the bearing cup.
According to this, the axial load acting between the inner bottom surface of the bearing cup and the shaft portion of the cross shaft can be received by the bearing cup through the protruding portion of the resin cover, and the inner bottom surface of the bearing cup. In addition, damage and seizure of the end face of the shaft portion can be prevented. For this reason, the thrust washer conventionally required in order to receive an axial load can be made unnecessary.

Further, in this cross joint, the cover has a protruding portion that protrudes outward in the axial direction of the shaft portion, and the tip surface of the protruding portion serves as the contact surface, and the contact surface is more than the shaft portion. A circular surface with a small diameter is preferred.
Thereby, the contact area between the protrusion part of a cover and the inner bottom face of a bearing cup can be made small, and the rotational resistance between the inner bottom face of a bearing cup and the axial part of a cross shaft can be made small.

Further, in this cross shaft joint, a space portion that allows elastic deformation of the protruding portion toward the shaft portion side is formed between a surface of the protruding portion on the shaft portion side and an end surface of the shaft portion. It is preferable.
According to this, when an axial load is applied between the inner bottom surface of the bearing cup and the shaft portion of the cross shaft, an elastic deformation is generated in the projecting portion to crush the space portion in the axial direction. Thereby, for example, when an annular seal member is provided at the base end portion of the shaft portion of the cross shaft, and the end surface of the bearing cup is in contact with this seal member, even if a large axial load acts suddenly, Due to the elastic deformation by the protruding portion of the cover, the impact can be absorbed, and the end face of the bearing cup does not give an impact to the seal member, and the seal member can be protected.

In this cross joint, the cover is preferably fitted in close contact with the outer peripheral surface of the reduced diameter portion formed at the tip of the shaft portion.
According to this, the cover is pushed radially inward by fitting the rolling element in the bearing cup to the cover, but the cover is fitted on the outer peripheral surface of the reduced diameter portion of the shaft portion. The shape of the cover is maintained by the reduced diameter portion, and can be prevented from being greatly deformed. Also,
A state in which the cover is attached to the shaft portion is obtained by fitting the cover to the reduced diameter portion at the tip of the shaft portion.

  According to this invention, when arranging a plurality of rolling elements on the inner periphery of the bearing cup and fitting the rolling elements from the tip end side of the shaft portion of the cross shaft, the rolling elements first come into contact with the resin cover. This cover can prevent damage to the tip of the shaft and the rolling element. Thereby, the quality of a cross-shaft joint can be improved and durability can be improved.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a side view showing an embodiment of a universal joint having a cross joint according to the present invention, and FIG. 2 is a cross-sectional view taken along the line II-II of FIG. The universal joint J can be used to connect the steering shaft 31 and the column shaft 32 in, for example, an automobile steering apparatus. In the form of FIG. 1, an intermediate shaft 33 is interposed between the shafts 31 and 32, and a cross joint is provided between the intermediate shaft 33 and the steering shaft 31 and between the intermediate shaft 33 and the column shaft 32. 10 is provided.

  A pair of opposing yokes 21, 22 are provided at the end of the steering shaft 31, and bearing holes 21 a, 22 a having the same axis are formed in each of the yokes 21, 22. On the other hand, a pair of opposing yokes 23 and 24 are provided at the end of the intermediate shaft 33, and bearing holes 23a and 24a having the same axis are formed in the yokes 23 and 24, respectively.

The cross shaft joint 10 includes a cross shaft 1 having four shaft portions 3, a needle roller 6 as a plurality of rolling elements that roll on the outer peripheral surface 3a of the shaft portion 3, and an outer fit to the plurality of rolling elements. The bottomed cylindrical bearing cup 5 is provided.
Then, each shaft portion 3 of the cross shaft 1 has its axis line through a bottomed cylindrical bearing cup 5 in which a plurality of needle rollers 6 are arranged on the inner periphery in each of the bearing holes 21a, 22a, 23a, 24a. It is supported so that it can rotate freely. The structure between the intermediate shaft 33 and the column shaft 32 is the same, and a description thereof is omitted.

  FIG. 3 is a cross-sectional view showing the main part of the cross joint, and shows the main part of the cross joint 10 in the yoke 21. The cross shaft 1 has a body portion 2 and four shaft portions 3 protruding in four directions from the side peripheral surface of the body portion 2. The cross shaft 1 is made of steel, and the body portion 2 and the four shaft portions 3 are integrally formed by forging. The bearing cup 5 has a cylindrical portion 8a and a disc portion 8b continuous with an end portion of the cylindrical portion 8a, and has a bottomed cylindrical shape. And the internal peripheral surface of the cylindrical part 8a is made into the track surface. The needle roller 6 and the bearing cup 5 are made of steel.

  In the assembled state, the bearing cup 5 is in a state of being fitted into the bearing hole 21 a of the yoke 21 in the cylindrical portion 8 a, and the shaft portions of the plurality of needle rollers 6 and the cross shaft 1 in the bearing cup 5. 3 is maintained in an interference fit state. That is, the radial gap after the assembly in the needle roller 6 of this bearing cup 5 is set as the negative gap.

  A resin cover 7 is attached to the tip of the shaft portion 3 of the cross shaft 1. The cover 7 has an annular portion 14 that covers the outer peripheral edge portion 4 a of the end surface 4 of the shaft portion 3, and a disc portion 16 that is integral with the annular portion 14 and covers the center portion of the end surface 4 of the shaft portion 3. is doing. Further, the outer peripheral surface 14 a of the annular portion 14 is flush with the outer peripheral surface 3 a of the shaft portion 3 (a structure on the same circumferential surface). The cover 7 has a structure covering the entire end surface 4 of the shaft portion 3.

  In FIG. 3, the end surface 4 of the shaft portion 3 of the cross shaft 1 has a stepped shape, and a reduced diameter portion 13 having a circular cross section with a reduced outer diameter is formed in the center portion of the end surface 4. When the annular portion 14 of the cover 7 is brought into close contact with the outer peripheral surface 13 a of the reduced diameter portion 13 and is externally fitted, the cover 7 is attached to the tip of the shaft portion 3. Thereby, in the state which attached the cover 7 to the front-end | tip of the axial part 3, the operation | work which attaches the bearing cup 5 to the said axial part 3 externally becomes easy. Further, the cover 7 is pushed radially inward by fitting the needle roller 6 in the bearing cup 5 to the cover 7. The cover 7 is fitted on the outer peripheral surface 13 a of the reduced diameter portion 13 of the shaft portion 3. Therefore, the shape of the cover 7 is maintained by the reduced diameter portion 13 and can be prevented from being greatly deformed.

  The cover 7 has a contact surface 11 a that contacts the inner bottom surface of the bearing cup 5. More specifically, the disc portion 16 of the cover 7 has a protruding portion 11 protruding outward in the axial direction of the shaft portion 3, and the tip of the protruding portion 11 serves as the contact surface 11a. The contact surface 11 a is a circular surface and has a diameter smaller than that of the shaft portion 3 and the annular portion 14 of the cover 7. Further, the protruding portion 11 protrudes from the central portion of the disc portion 16, and the contact surface 11 a that is the end surface of the protruding portion 11 is in contact with the central portion of the inner surface of the disc portion 8 b of the bearing cup 5. .

  Although the cover 7 is made of resin, those having excellent mechanical properties and heat resistance are preferable, and those having self-lubricating properties and excellent friction and wear resistance and fatigue resistance are more preferable. Specifically, it can be a synthetic resin such as polyacetal or polyphenylene sulfide resin.

  FIG. 4 is an explanatory view illustrating a method for assembling the universal joint J provided with the cross joint 10. In this figure, the assembly of the universal joint J is as follows. First, the cross shaft 1 of the pair of opposing yokes 21 and 22 is made to approach obliquely toward one yoke 22 and one shaft portion 3 of the cross shaft 1 is moved. After inserting into the bearing hole 22 a of the yoke 22, the other opposite shaft portion 3 is inserted into the bearing hole 21 a of the other yoke 21. Then, in a state where the shaft portion 3 of the cross shaft 1 is inserted into the bearing hole 21a, the bearing cup 5 in which a plurality of needle rollers 6 are arranged along the inner periphery from the outside in the axial direction of the shaft portion 3 is inserted into the shaft portion 3. The needle roller 6 in the bearing cup 5 is fitted from the tip end side of the shaft portion 3 while the bearing cup 5 is press-fitted into the bearing hole 21a, and the diameter of the bearing cup 5 is reduced. It will be in the state which press-contacted with the axial part 3, ie, an interference fit state. Similarly, in the bearing hole 22 a on the yoke 22 side, a bearing cup (not shown) in which a plurality of needle rollers are arranged on the inner periphery is attached to the shaft portion 3. Before the assembly, an annular seal member 15 is provided in advance at the base end portion of the shaft portion 3 of the cross shaft 1.

In order to make the needle roller 6 of the bearing cup 5 and the shaft portion 3 of the cross shaft 1 in an interference-fit state in the assembled state, when the bearing cup 5 is attached to the shaft portion 3 as described above, the bearing cup 5 is inserted into the bearing hole. The bearing cup 5 is reduced in diameter by press-fitting into 21a. For this reason, the needle roller 6 on the inner periphery tries to contact the outer peripheral edge 4 a of the end surface 4 of the shaft 3, but the outer peripheral edge 4 a is covered by the annular portion 14 of the resin cover 7. Therefore, the rolling element 6 first comes into contact with the annular portion 14 to prevent damage to the end surface 4 of the shaft portion 3 and the needle roller 6. Further, the outer peripheral surface 14a of the cover 7 and the outer periphery of the tip end of the shaft portion 3 can be prevented. Since the surface 3a is flush with the surface 3a, once the needle roller 6 is fitted onto the annular portion 14 of the cover 7, the needle roller 6 is smoothly attached to the shaft portion 3 simply by moving the bearing cup 5 in the axial direction. Can be fitted.

A load in a direction perpendicular to the axis of the shafts 31 and 33 acts on the cross joint 10 between the shafts 31 and 33 shown in FIG. 2 and 3, the bearing cups 5 are fitted in the respective bearing holes of the yokes of the shafts 31 and 33, and are fixed to the inner bottom surface of the bearing cup 5 at the tip of the shaft portion 3 of the cross shaft 1. The protrusion 11 of the fixed cover 7 is in contact. Therefore, the load acts as a load in the axial direction of the shaft portion 3 (hereinafter referred to as an axial load) between the bearing cup 5 and the shaft portion 3 of the cross shaft 1.
Therefore, according to the cross joint 10, the axial load between the inner bottom surface of the bearing cup 5 and the shaft portion 3 of the cross shaft 1 is transferred to the bearing cup 5 via the protrusion 11 of the resin cover 7. The inner bottom can be received. Thereby, damage to the inner bottom face of the bearing cup 5 and the end face 4 of the shaft portion 3 can be prevented.

Further, since the contact surface 11a of the protrusion 11 with respect to the inner bottom surface of the bearing cup 5 is a circular surface smaller than the diameter of the shaft portion 3, the contact area can be reduced and the axial load acts. At the same time, even if rotation occurs between the bearing cup 5 and the shaft portion 3 of the cross shaft 1, the rotational resistance between the inner bottom surface of the bearing cup 5 and the shaft portion 3 of the cross shaft 1 can be reduced.
Further, since the disk portion 16 of the cover 7 is in contact with the end surface 4 of the shaft portion 3 in a circumferentially continuous surface, even when a large axial load is applied, the load is applied to the shaft portion. 3 can be uniformly applied to the end surface 4 and dispersed, and the surface pressure can be reduced. Further, the cover 7 and the end surface 4 of the shaft portion 3 are in contact with each other on a circumferentially continuous surface, and there is no gap between them, so that an axial load is applied between the shaft portion 3 and the bearing cup 5. Even if it is rotated at, no abnormal noise is generated between them. Further, the axial load is uniformly applied to the end surface 4 of the shaft portion 3 to be dispersed to obtain a uniform surface pressure, and the transmission torque fluctuation in the cross joint 10 can be suppressed. Conventionally, there has been proposed a structure using a washer having a spring property in which a plurality of irregularities are formed in the circumferential direction to have a waveform in the circumferential direction. However, in this case, there is a possibility that the abnormal noise occurs or the transmission torque fluctuates greatly.
In the present invention, a solid lubricant or grease may be interposed between the protruding portion 11 of the cover 7 and the inner bottom surface of the bearing cup 5, thereby further improving the lubricity. .

  In FIG. 3, an annular flange 18 that is bent radially inward from the end of the cylindrical portion 8 a is formed at the end of the bearing cup 5 on the opening side. An annular seal member 15 is fitted on the base end portion of the shaft portion 3, and the seal member 15 and the flange portion 18 are in contact with each other. Thereby, it can prevent that a foreign material penetrate | invades into the needle roller 6 side. Further, the protrusion 11 of the cover 7 at the tip of the shaft portion 3 comes into contact with the inner bottom surface of the bearing cup 5, so that the bearing cup 5 is restricted from moving toward the proximal end side in the axial direction of the shaft portion 3. The Thereby, it can prevent that the said collar part 18 of the bearing cup 5 crushes the sealing member 15 too much by the said axial load.

FIG. 5 is a cross-sectional view showing a main part of another embodiment of the cross joint. The cross joint 10 is different from the above embodiment with respect to the cover 7, but the other configurations are the same. In the cover 7, a space portion 12 is formed between a surface (back surface) 11 b of the protruding portion 11 on the shaft portion 3 side and the center portion of the end surface 4 of the shaft portion 3. Accordingly, when the axial load is generated, the projecting portion 11 is deformed so as to crush the space portion 12 in the axial direction, thereby enabling an elastic compressive deformation.
Here, an annular seal member 15 is provided at the base end portion of the shaft portion 3 of the cross shaft 1, and the flange portion 18 of the bearing cup 5 is in contact with the seal member 15 from a direction parallel to the axis. Therefore, when a large axial load is applied suddenly, the flange portion 18 tries to suddenly crush the seal member 15 due to the impact. However, even in this case, the elastic compression deformation by the protruding portion 11 of the cover 7 can absorb the impact, and the seal member 15 can be protected without being suddenly crushed.

Moreover, FIG. 6 is sectional drawing which shows the principal part of another embodiment of a cross-shaft coupling. The cross shaft joint 10 is different from the above-described embodiment with respect to the cover 7 and the tip portion of the shaft portion 3, but the other configurations are the same. In this embodiment, a recess 26 is formed in the central portion of the end surface 4 of the shaft portion 3. A protrusion 27 that fits into the recess 26 is formed on the cover 7. Thus, by fitting the protrusion 27 of the cover 7 into the recess 26 in the end surface 4 of the shaft portion 3, the cover 7 is attached at the tip of the shaft portion 3 so as to cover the end surface 4 including the outer peripheral edge portion 4 a. be able to.
Accordingly, when the bearing cup 5 in which the needle rollers 6 are arranged on the inner periphery is press-fitted into the bearing hole 21a of the yoke 21, and when the needle roller 6 is externally fitted from the distal end side of the shaft portion 3, the needle roller 6 is It slides on the outer peripheral surface 14 a of the cover 7. As a result, even if the cover 7 is pulled by the needle roller 6 and is about to deviate from a predetermined position, the outer peripheral surface of the projection 27 of the cover 7 is caught on the inner peripheral surface of the concave portion 26 of the shaft portion 3, and the cover 7 is Misalignment can be prevented.
In addition, about the said recessed part 26 of the axial part 3, and the said projection part 27 of the cover 7, it can employ | adopt also in embodiment shown in FIG.

FIG.7 and FIG.8 is sectional drawing which shows the principal part of further another embodiment of a cross shaft coupling. Each of these is a modification of the embodiment of FIG. 6, and an annular relief portion 30 such as a chamfered portion 28 (see FIG. 7) or a rounded surface portion 29 is formed on the outer peripheral portion at the tip of the shaft portion 3 of the cross shaft 1. ing.
In this configuration, as shown in FIGS. 7B and 8B, a bearing cup (not shown) in which the needle rollers 6 are arranged on the inner periphery is provided in a bearing hole (not shown) of the yoke. When the needle roller 6 is fitted from the distal end side of the shaft portion 3 while being press-fitted, the needle roller 6 slides on the outer peripheral surface 14 a of the cover 7, and the outer peripheral portion of the cover 7 is drawn by the needle roller 6. However, according to the escape portion 30, a part of the outer peripheral edge of the cover 7 can move to the escape portion 30. Thereby, the resistance between the needle roller 6 and the shaft portion 3 can be reduced, and the external fitting of the needle roller 6 to the shaft portion 3 can be made smooth. Furthermore, when the needle roller 6 is externally fitted from the distal end side of the shaft portion 3, it is possible to prevent the outer peripheral portion of the cover 7 from being rubbed against the needle roller 6 and peeling off the outer peripheral portion.

Further, in the embodiment of FIGS. 7 and 8, as shown in FIG. 6, the cover 7 is displaced by providing the concave portion 26 in the shaft portion 3 and providing the projection portion 27 in the cover 7. In addition, the relief portion 30 can smoothly fit the needle roller 6 to the shaft portion 3, and can prevent the outer peripheral portion of the cover 7 from peeling off.
7 and 8, the resin cover 7 provided in the cross shaft joint 10 covers the outer peripheral edge 4 a of the end surface 4 of the shaft portion 3 of the cross shaft 1 and also covers the cover 7. The outer circumferential surface 14a is on the same circumferential surface through the outer circumferential surface 3a of the shaft portion 3 and the relief portion 30.

As described above, according to each embodiment, when the bearing cup 5 in which the needle rollers 6 are arranged on the inner periphery is attached by being fitted from the distal end side of the shaft portion 3 of the cross shaft 1, the needle roller 6 is first attached to the cover 7. Contact the outer periphery. Since the cover 7 is made of resin, the cover 7 is sufficiently softer than the steel needle roller 6, and the needle roller 6 is not damaged even if it contacts. The needle roller 6 can be externally fitted to the outer periphery of the cover 7 by elastic deformation in which the outer peripheral portion (annular portion 14) of the cover 7 is reduced in diameter. The needle roller 6 is smoothly guided from the outer peripheral surface 14 a of the cover 7 to the outer peripheral surface 3 a of the shaft portion 3 by moving the bearing cup 5 toward the proximal end portion of the shaft portion 3 of the cross shaft 1. Thereby, the front-end | tip of the axial part 3, outer peripheral surface 3a (namely, track surface), and the damage to the needle roller 6 can be prevented.
From the above, the assembled cross joint 10 can be of high quality, and durability can be improved. In addition, since the cover 7 is attached to the tip of the shaft portion 3, the structure is simple and it can be manufactured at low cost.
Further, since the resin cover 7 is provided at each tip of the four shaft portions 3 and the contact surface 11 a with the inner bottom surface of the bearing cup 5 is provided on the cover 7, the accuracy of the tip of the shaft portion 3 is improved. High machining is not required and it can be manufactured at low cost.

  In addition, the cross joint of the present invention is not limited to the illustrated form, and may have other forms within the scope of the present invention. In the above embodiment, the outer peripheral surface of the end portion of the needle roller 6 is in contact with the outer peripheral surface 14a of the cover 7. Although not shown, the needle roller is in contact with only the outer peripheral surface of the shaft portion. Can do.

Further, for example, the resin cover 7 only needs to have a structure that covers at least the outer peripheral edge portion 4a of the end surface 4 of the shaft portion 3, and an annular ring portion 14 that covers the outer peripheral edge portion 4a similar to the above-described embodiment; In addition, the cover 7 may include the central projecting portion 11 and a connecting portion (not shown) that connects the annular portion 14 and the projecting portion 11.
Alternatively, as shown in FIG. 9, an annular cover 7 that covers only the outer peripheral edge 4 a of the end surface 4 of the shaft portion 3 can be used. In this case, the cover 7 may be brought into close contact with the outer peripheral surface of the reduced diameter portion 13 formed at the tip of the shaft portion 3.

It is a side view which shows one Embodiment of the universal joint provided with the cross shaft coupling of this invention. It is sectional drawing in the II-II cross section of FIG. It is sectional drawing which shows the principal part of a cross shaft coupling. It is explanatory drawing explaining the assembly method of the universal joint provided with the cross shaft coupling. It is sectional drawing which shows the principal part of other embodiment of a cross shaft coupling. It is sectional drawing which shows the principal part of another embodiment of a cross shaft coupling. It is sectional drawing which shows the principal part of further another embodiment of a cross shaft coupling. It is sectional drawing which shows the principal part of further another embodiment of a cross shaft coupling. It is sectional drawing explaining the modification of a cover. It is explanatory drawing explaining the assembly of the joint structure provided with the conventional cross shaft joint.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cross shaft 2 Body part 3 Shaft part 3a Outer peripheral surface 4 End surface 4a Outer peripheral edge part 5 Bearing cup 6 Needle roller (rolling element)
7 Cover 10 Cross shaft joint 11 Protruding portion 11a Contact surface 12 Space portion 13 Reduced diameter portion 13a Outer peripheral surface 14 Circular portion 21, 22, 23, 24 Yoke 21a, 22a, 23a, 24a Bearing hole 31 Steering shaft 32 Column shaft 33 Intermediate shaft

Claims (5)

A cross shaft having four shaft portions protruding in four directions from the side peripheral surface of the body portion;
A plurality of rolling elements that roll on the outer peripheral surface of the shaft portion;
A bottomed cylindrical bearing cup externally fitted to the plurality of rolling elements,
In the cross shaft joint in which the rolling element is maintained in an interference fit with the shaft portion,
A cross shaft characterized in that a resin cover that covers at least the outer peripheral edge portion of the end surface of the shaft portion and whose outer peripheral surface is flush with the outer peripheral surface of the shaft portion is attached to the tip end of the shaft portion. Fittings.   The cross shaft joint according to claim 1, wherein the cover has a contact surface that contacts an inner bottom surface of the bearing cup.   The cover has a protruding portion that protrudes outward in the axial direction of the shaft portion, and the tip surface of the protruding portion serves as the contact surface, and the contact surface is a circular surface having a smaller diameter than the shaft portion. The cross joint according to claim 2.   The cross according to claim 3, wherein a space that allows elastic deformation of the protruding portion toward the shaft portion is formed between a surface of the protruding portion on the shaft portion side and an end surface of the shaft portion. Shaft coupling.   The cross shaft joint according to any one of claims 1 to 4, wherein the cover is fitted in close contact with an outer peripheral surface of a reduced diameter portion formed at a tip of the shaft portion.

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