JP3945211B2 - Cross shaft coupling - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cross joint for use in, for example, a vehicle steering apparatus.
[0002]
[Prior art]
In a vehicle steering system, for example, a cross shaft joint that consists of a pair of yokes and a cross-shaped spider between an upper shaft and a lower shaft of a steering shaft and transmits torque while rotating at a predetermined bending angle is interposed. It is disguised.
[0003]
For example, in the cross shaft joint disclosed in Japanese Patent Application Laid-Open No. 2000-170786, the shaft portion of the spider is rotatably fitted in the bearing hole of the yoke via a needle bearing. A spherical protrusion formed on the shaft core of the inner surface of the cup of the needle bearing is fitted and pressed into a conical hole formed in the shaft core of the spider shaft.
[0004]
Thereby, even if vibration is transmitted from the wheel, the minute gap between the spider shaft and the needle bearing is maintained uniformly, and the generation of noise due to the interference between the two is prevented.
[0005]
[Problems to be solved by the invention]
However, in the configuration of the above Japanese Patent Laid-Open No. 2000-170786, when the dimensional accuracy of each part is low, the spherical surface of the inner surface of the needle bearing cup is inserted into the conical hole of the spider shaft when the cross joint is assembled into the yoke. It is difficult to contact the protruding portion with an appropriate preload, and as a result, the minute gap between the spider shaft and the needle bearing cannot be maintained uniformly, and abnormal noise is generated due to interference between the two. is there.
[0006]
On the other hand, if the dimensional accuracy of each part is increased, the generation of abnormal noise can be prevented, but on the other hand, the manufacturing cost may increase.
[0007]
The present invention has been made in view of the circumstances described above, and can reliably prevent the generation of noise due to interference between the spider shaft and the needle bearing without incurring an increase in manufacturing cost. An object is to provide a cross joint.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, in the cross shaft joint in which the spider shaft portion is rotatably fitted to the bearing hole of the yoke via the rolling bearing, the spider shaft portion includes the spider shaft. Forming a contact portion with the rolling bearing having an outer diameter larger than the outer diameter of the shaft portion;
The contact portion and the rolling bearing are fitted with each other,
A cross shaft joint is provided in which a bottomed hole is formed in an end face of the shaft core of the contact portion .
[0010]
Thus, according to the present invention, the contact portion of the spider shaft portion has an outer diameter Yes formed larger than the outer diameter of the central portion, to set the fitting of the contact portion between the rolling bearing to Interference It is . Therefore, even if vibration is transmitted from the wheel, the minute gap between the central portion of the spider shaft and the rolling bearing can be maintained uniformly, and the generation of noise due to the interference between the two can be reliably prevented.
[0011]
On the other hand, the contact portion of the spider shaft portion has a relatively thin ring shape as a result of the bottomed hole being formed on the end surface of the shaft core. Therefore, the contact portion has a relatively small radial rigidity, and even if the contact portion and the rolling bearing are fitted to each other, the contact surface pressure does not increase so much, causing a problem of durability. There is no such thing. Similarly, when the cross joint is assembled into the yoke, the load for inserting (press-fitting) the rolling bearing (needle bearing) is relatively small, and there is no problem in assembling.
[0012]
Further, it is not necessary to increase the dimensional accuracy of each component, and the contact portion of the spider shaft portion is enlarged and the bottomed hole is formed, so that the manufacturing cost is not increased.
[0013]
Furthermore, since the contact part of the spider shaft part has a relatively thin ring shape as described above, when a large load is transmitted, the contact part bends, but the center part of the spider shaft part is loaded. Because it receives most, it does not cause any strength problems.
[0014]
The cross joint of the present invention is characterized in that an extreme pressure additive is added to the lubricant enclosed in the needle bearing.
Furthermore, the cross shaft joint of the present invention comprises a pair of yokes and a cross-shaped spider that connects the yokes, and a spider shaft corresponding to the spider shaft is respectively provided in each pair of bearing holes formed in the yoke. In a cross shaft joint that is rotatably fitted via a rolling bearing, at least one of the spider shaft portions forms a contact portion with the rolling bearing having an outer diameter larger than the outer diameter of the spider shaft portion, The contact portion and the rolling bearing are fitted to each other, and a bottomed hole is formed in an end surface of the shaft core of the contact portion .
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a cross joint according to an embodiment of the present invention will be described with reference to the drawings.
[0016]
(First embodiment)
FIG. 1 is a side view including a partially cutaway cross section of the cross joint according to the first embodiment of the present invention. 2 is a cross-sectional view of the cross joint shown in FIG.
[0017]
As shown in FIG. 1, in the cross joint, a cross-shaped spider 3 is interposed between a pair of yokes 1 and 2. Specifically, as shown in FIG. 2, a spider shaft portion 6 is rotatably fitted in a bearing hole 4 of the yoke 1 via a needle bearing 5, and the spider shaft portion 6 has a lower outer periphery. The seal member 7 is provided. In the present embodiment and each of the following embodiments, the yoke may be made by any of sheet metal, forging, and casting, and the yoke material may be either iron or aluminum.
[0018]
A synthetic resin pin 9 is inserted into an axial hole 8 formed in the shaft core of the spider shaft 6. The needle bearing 5 is provided with a metal cup 10 fitted in the bearing hole 4, and a plurality of roller rolling elements 11 are arranged inside the cup 10.
[0019]
In the present embodiment, the outer diameter of the contact portion 6a of the spider shaft portion 6 is formed larger than the outer diameter of the center portion 6b, and the bottomed hole 12 is formed on the end surface of the axial center of the contact portion 6a. It is.
[0020]
Thus, since the outer diameter of the contact portion 6a of the spider shaft portion 6 is formed larger than the outer diameter of the central portion 6b, the fitting between the contact portion 6a and the needle bearing 5 is performed with a small amount (or a minute amount). Gap). Therefore, even if vibration is transmitted from the wheels, the minute gap between the central portion 6b of the spider shaft portion 6 and the needle bearing 5 is maintained uniformly, and generation of abnormal noise due to interference between the two is reliably prevented. Can do.
[0021]
On the other hand, the contact portion 6a of the spider shaft portion 6 has a relatively thin ring shape as a result of the bottomed hole 12 being formed on the end surface of the shaft core. Therefore, the contact portion 6a has a relatively small radial rigidity, and even if the contact portion 6a and the needle bearing 5 are fitted to each other, the contact surface pressure does not increase so much, which is a problem of durability. Does not occur. Similarly, when the cross shaft joint is assembled into the yoke 1, the load for inserting (press-fitting) the needle bearing 5 is relatively small, and there is no trouble in assembling.
[0022]
Further, it is not necessary to increase the dimensional accuracy of each component, and the contact portion 6a of the spider shaft portion 6 is enlarged and the bottomed hole 12 is formed, so that the manufacturing cost is not increased.
[0023]
Furthermore, since the contact part 6a of the spider shaft part 6 has a relatively thin ring shape as described above, the contact part 6a bends when a large load is transmitted, but the center of the spider shaft part 6 Since the portion 6b receives most of the load, there is no problem in strength.
[0024]
In addition, the shaft diameter of the spider shaft portion 6 is about 10 mm, the depth of the bottomed hole 12 is 1.8 to 3.5 mm, preferably 2 to 3 mm, and the contact portion 6a is thin. The radial thickness of the ring-shaped portion is 0.6 to 1.2 mm, and the step (S in FIG. 2, that is, the minute gap between the central portion 6 b and the roller rolling element 11) is 0.004 to 0. .020 mm. Note that the minute gap indicated by the symbol S in FIG. 2 is exaggerated.
[0025]
The material of the spider 3 is JIS chrome molybdenum steel material SCM420 or 421, or chrome steel material SCr420 or 430. Furthermore, the heat treatment of the spider 3 is full-surface carburizing and quenching, and preferably, the bottomed hole 12 portion is protected against carbon. Further, the outer diameter portion of the spider shaft portion 6 is a grinding process, and the chamfered portion of the end surface is not ground. Furthermore, the cross joint according to the present embodiment is mainly used in a vehicle engine room.
[0026]
(Second Embodiment)
FIG. 3 is a sectional view of a cross joint according to the second embodiment of the present invention. In the present embodiment, since the synthetic resin pin 9 is not provided, the shape of the bottomed hole 12 is a conical shape, and the cost can be reduced as compared with the first embodiment.
[0027]
However, the cross joint according to the present embodiment is limited to use in the cab. The seal member 7 is made of nitrile rubber. Other configurations and operations are the same as those in the first embodiment.
[0028]
(Third embodiment)
FIG. 4 is a sectional view of a cross joint according to the third embodiment of the present invention. In the present embodiment, the contact portion of the spider shaft is configured separately. That is, an axial hole 13 is formed in the spider shaft 6, and a separate spacer 14 is attached to the axial hole 13.
[0029]
The protrusion 14a of the spacer 14 is press-fitted into the axial hole 13, and the thin ring-shaped portion 14b of the spacer 14 functions in the same manner as the contact portion 6a of the first and second embodiments. ing. In the present embodiment, grinding of the spider outer diameter is easier than in the first and second embodiments. Other configurations and operations are the same as those in the first embodiment.
[0030]
(Fourth embodiment)
FIG. 5 is a cross-sectional view of the cross joint according to the fourth embodiment of the present invention. In the present embodiment, the bottomed hole 12 is not provided as compared with the first embodiment.
[0031]
For this reason, compared with 1st Embodiment, the process of the spider shaft part 6 becomes easy. However, since the contact surface pressure with the needle bearing 5 is higher than that in the first embodiment, it is necessary to make the contact with the needle bearing 5 smaller than that in the first embodiment. Other configurations and operations are the same as those in the first embodiment.
[0032]
(Fifth embodiment)
FIG. 6 is a sectional view of a cross joint according to the fifth embodiment of the present invention. In the present embodiment, compared to the first embodiment, the spider shaft portion 6 is solid without providing the axial hole 8, and the bottom center portion 15 of the cup 10 of the needle bearing 5 is brought into contact with the end surface of the spider shaft portion 6. It is made the composition made to do.
[0033]
For this reason, compared with 1st Embodiment, the process of the spider shaft part 6 becomes easy. However, since the contact surface pressure with the needle bearing 5 is higher than that in the first embodiment, it is necessary to make the contact with the needle bearing 5 smaller than that in the first embodiment. Other configurations and operations are the same as those in the first embodiment.
[0034]
(Sixth embodiment)
FIG. 7 is a cross-sectional view of the cross joint according to the sixth embodiment of the present invention. In the present embodiment, the portion that becomes a squeezing fit between the needle bearing 5 and the contact portion 6 a of the spider shaft portion 6 is configured to be a portion near the root of the spider shaft portion 6.
[0035]
For this reason, compared with 1st Embodiment, the process of the spider shaft part 6 becomes easy. Other configurations and operations are the same as those in the first embodiment.
[0036]
In the fourth to sixth embodiments, the contact portion 6a of the spider shaft portion 6 may be provided at any place from the tip of the spider shaft portion 6 to the root.
(Seventh embodiment)
FIG. 8 is a cross-sectional view of a cross joint according to a seventh embodiment of the present invention (a cross-sectional view in the direction of the longitudinal axis of the joint center in FIG. 1). In the present embodiment, one of the two opposing spider shaft portions 6 (the upper side in FIG. 8) is a shimiro fitting, and the other (the lower side in FIG. 8) is a clearance fitting.
[0037]
One spider shaft 6 (upper side in FIG. 8) on the side of the shimoshiro fitting has a contact portion (large diameter portion) 6a in a portion close to the root, and the tip portion is a gap fitting.
[0038]
The spider shaft portion 6 (the lower side in FIG. 8) on the other clearance fitting side does not have a stepped portion and is formed in a straight shape.
[0039]
The spider shaft portion 6 orthogonal to the spider shaft portion 6 has the same configuration. Other configurations and operations are the same as those in the first embodiment.
[0040]
In the case of this embodiment, the cost may be lower than that of the first, second, fourth, fifth, and sixth embodiments, but the noise prevention effect is inferior. In addition, when the spider shaft portion 6 having the contact portion (large diameter portion) 6a that is fitted with shimeshiro is provided at only one of the four locations, the cost can be further reduced, but the noise prevention effect is further reduced.
[0041]
(Eighth embodiment)
FIG. 9 is a sectional view of a cross joint according to the eighth embodiment of the present invention. In the present embodiment, the contact portion (large diameter portion) 6 a that is fitted with a shimiro is the base side of the spider shaft portion 6, and a piece 16 is provided between the bottom surface of the cup 10 and the end surface of the spider shaft portion 6. is there. Other configurations and operations are the same as those in the first embodiment.
[0042]
In addition, the fitting length (L) of the shimoshiro portion is set to 1.5 mm or more, preferably 2 mm or more from the calculation and many test results. Thereby, durability can be ensured. This numerical value is the same in the fourth to seventh embodiments.
[0043]
In addition, the outer diameter of the roller rolling element 11 is 1.4 to 2.3 mm, the number of the roller rolling elements 11 is 16 to 25, and the outer diameter of the cup 10 is 15 to 16 mm. These are the same in the first to eighth embodiments.
[0044]
Further, an extreme pressure additive is added to the grease (lubricant) sealed in the internal space 5 a of the needle bearing 5. Thereby, bending torque can be further reduced. As a specific material of the extreme pressure additive, for example,
Molybdenum disulfide, sulfur-based (S) extreme pressure additive, sulfur-phosphorus-based (SP) extreme pressure additive, zinc-sulfur-phosphorus-based (Zn-SP) extreme pressure additive, and the like. This grease may also be used in other embodiments.
[0045]
In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible.
[0046]
【The invention's effect】
As described above, according to the present invention, the contact portion of the spider shaft portion is formed so that the outer diameter thereof is larger than the outer diameter of the central portion thereof. It is set to . Therefore, even if vibration is transmitted from the wheel, the minute gap between the central portion of the spider shaft and the rolling bearing can be maintained uniformly, and the generation of noise due to the interference between the two can be reliably prevented.
[0047]
On the other hand, the contact portion of the spider shaft portion has a relatively thin ring shape as a result of the bottomed hole being formed on the end surface of the shaft core. Therefore, the contact portion has a relatively small radial rigidity, and even if the contact portion and the rolling bearing are fitted to each other, the contact surface pressure does not increase so much. It does not cause any problems. Similarly, when the cross joint is assembled into the yoke, the load for inserting (press-fitting) the rolling bearing (needle bearing) is relatively small, and there is no problem in assembling.
[0048]
Further, it is not necessary to increase the dimensional accuracy of each component, and the contact portion of the spider shaft portion is enlarged and the bottomed hole is formed, so that the manufacturing cost is not increased.
[0049]
Furthermore, since the contact part of the spider shaft part has a relatively thin ring shape as described above, when a large load is transmitted, the contact part bends, but the center part of the spider shaft part is loaded. Because it receives most, it does not cause any strength problems.
[Brief description of the drawings]
FIG. 1 is a side view including a partially cutaway cross section of a cross joint according to a first embodiment of the present invention.
2 is a cross-sectional view of the cross joint shown in FIG. 1. FIG.
FIG. 3 is a cross-sectional view of a cross shaft joint according to a second embodiment of the present invention.
FIG. 4 is a cross-sectional view of a cruciform joint according to a third embodiment of the present invention.
FIG. 5 is a cross-sectional view of a cruciform joint according to a fourth embodiment of the present invention.
FIG. 6 is a cross-sectional view of a cruciform joint according to a fifth embodiment of the present invention.
FIG. 7 is a cross-sectional view of a cruciform joint according to a sixth embodiment of the present invention.
FIG. 8 is a cross-sectional view of a cross joint according to a seventh embodiment of the present invention (a cross-sectional view in the longitudinal direction of the joint center in FIG. 1).
FIG. 9 is a cross-sectional view of a cross joint according to an eighth embodiment of the present invention.
[Explanation of symbols]
1, 2 Yoke 3 Spider 4 Bearing hole 5 Needle bearing (rolling bearing)
6 Spider shaft 6a Contact part (large diameter part)
6b Central part 7 Seal member 8 Axial hole 9 Synthetic resin pin 10 Cup 11 Roller rolling element 12 Bottom hole 13 Axial hole 14 Spacer 14a Projection 14b Thin ring-shaped part 15 Bottom center part 16 Piece

Claims (3)

In the cross shaft joint in which the spider shaft is rotatably fitted in the bearing hole of the yoke via the rolling bearing,
In the spider shaft portion, a contact portion with the rolling bearing having an outer diameter larger than the outer diameter of the spider shaft portion is formed ,
The contact portion and the rolling bearing are fitted with each other,
A cross shaft joint , wherein a bottomed hole is formed in an end surface of the shaft core of the contact portion . The cross shaft joint according to claim 1 , wherein an extreme pressure additive is added to the lubricant sealed in the needle bearing. A pair of yokes;
It consists of a cross-shaped spider that connects these yokes,
In the cross shaft joint in which the corresponding spider shaft portion of the spider shaft is rotatably fitted to each pair of bearing holes formed in the yoke via the rolling bearing,
For at least one of the spider shafts, forming a contact portion with the rolling bearing having an outer diameter larger than the outer diameter of the spider shaft ,
The contact portion and the rolling bearing are fitted with each other,
A cross shaft joint , wherein a bottomed hole is formed in an end surface of the shaft core of the contact portion .

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