JP3272136B2 - Bearing cup for universal joint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A universal joint bearing cup according to the present invention is incorporated in, for example, a propeller shaft or a steering shaft of an automobile, and transmits a rotational force by a non-linearly arranged propeller shaft or a steering shaft. It is used to construct a universal joint shell-type needle bearing that is free.

[0002]

2. Description of the Related Art A propeller shaft for transmitting rotation of an engine provided at a front portion of a vehicle to rear wheels, which are driving wheels, is configured as shown in FIG. 9, for example. In this propeller shaft 1, a sleeve yoke 2, which is connected to an output portion of a transmission and rotates, a first shaft 3, and a second shaft 4, are freely coupled to each other by universal joints 5, 5. In the configuration. The first shaft 3 is cushioned below the floor of the vehicle via a rubber bush 6. By such a propeller shaft 1, torque is transmitted between the output shaft of the transmission and the input shaft of the differential gear that are not on the same straight line.

As shown in FIG. 10, a universal joint 5 incorporated in such a propeller shaft has a structure in which first and second yokes 7, 8 each formed in a bifurcated shape, and both yokes 7, 8 are connected to each other. And a cross shaft 9 for connecting displaceably. Circular holes 10, 10 are formed at both ends of each of the yokes 7, 8 in a state where they are aligned with each other.
A bearing cup 11 (only one is shown in FIG. 10) is fitted and fixed inside each of the circular holes 10 and 10.

As shown in FIG. 11, a bearing cup 11 made of a hard metal material such as a case hardened steel plate is formed as a whole with an integral bottomed cylindrical shape. And a bottom portion 13 for closing one end of the bottom portion. On the inner surface of the bottom portion 13, for example, an annular ridge 14 is formed concentrically with the cylindrical portion 12.

As shown in FIG. 11, between the inner peripheral surfaces of a total of four bearing cups 11 fitted and fixed in the circular holes 10 and 10 and the outer peripheral surfaces of the four ends of the cross shaft 9 are shown. In this manner, a plurality of needles 15 are provided. Then, based on the rolling of the needles 15, 15, the cross shaft 9 and the first and second yokes 7, 8 (FIG. 10) can swing freely.
Further, the end face 16 of the cross shaft 9 and the bearing cup 1 facing each other.
The inner surface 17 of the bottom portion 13 is slid only in a small area at the tip of the ridge 14 to prevent a large frictional force from acting between the end surface 16 and the inner surface 17.

Since the universal joint 5 is constructed as described above, for example, as shown in FIG.
When the second yoke 8 is fixed to the end of the first shaft 3, the transmission of the rotational force between the sleeve yoke 2 and the first shaft 3 that do not exist on the same straight line is performed. I can do it.

In order to reduce the power loss at the universal joint 5, the frictional force acting between the end face 16 of the cross shaft 9 and the inner face 17 of the bottom 13 of each bearing cup 11 must be reduced. It is necessary to hold a sufficient amount of lubricating oil (generally grease) between both surfaces. As a structure for retaining the lubricating oil as described above, Japanese Unexamined Utility Model Publication No. 57-85625, Japanese Unexamined Patent Publication No. 54-89148, and Japanese Unexamined Patent Publication No.
Various structures described in Japanese Patent Publication No. 121 and the like are known.

[0008] Of these, the structure described in Japanese Utility Model Laid-Open No. 57-85625, as shown in FIG.
Are formed with a number of small concave portions 18. In the case of this structure, lubrication between the two surfaces 16, 17 is achieved by the lubricating oil held in the small concave portions 18, 18.

In the structure described in Japanese Patent Application Laid-Open No. 54-89148, as shown in FIG. 13, a plurality of ridges 19, 19 each having a trapezoidal or rectangular cross section are formed on the end face 16. , In the radial direction. In the case of this structure, the recess 2 existing between the adjacent ridges 19, 19
By the lubricating oil held in 0, 20, the above both sides 16,
17 lubrication.

Although not shown in the drawings, Japanese Patent Application Laid-Open No. 55-5 / 55
In the case of the structure described in JP-A-1121, a plurality of spherical or conical projections are formed on the inner surface of the bottom of the bearing cup. The plurality of projections separate the inner surface of the bottom portion from the end surface of the cross shaft and allow the lubricating oil to be fed between these two surfaces.

[0011]

However, in the case of the above-described conventional structure, the cross shaft 9 is not always required depending on the use condition.
A sufficient oil film cannot be formed between the end face 16 of the bearing cup 11 and the inner face 17 of the bottom 13 of each bearing cup 11. That is, universal joint angle of joint (or less eg 2 degrees) very small in the case, the relative rotation angle also very small between the end face 16 and the inner surface 17.

On the other hand, in the case of the conventional structure shown in FIGS.
Or, in the portions deviated from the recesses 20, 20, the planes face each other. As a result, when the relative rotation angle between the two surfaces 16 and 17 becomes extremely small, a part of the two surfaces 16 and 17 which always faces only flat surfaces (small recess 1) is formed.
8, 18 or the recesses 20, 20). No lubricating oil is supplied to these parts,
No oil film is formed. Therefore, both sides 16, 17
Metals are more likely to come into contact with each other, and when they are worn or marked, seizure is more likely to occur. In particular, if the lubrication failure occurs immediately after the universal joint is started and before the so-called familiarity is completed based on the initial wear of the end face 16 and the inner face 17 and the sliding contact portion, the seizure tends to occur.

In the case of the structure described in Japanese Patent Application Laid-Open No. 55-51221, the contact area between the tip end face of each projection and the cross-shaft end face is small, and a large surface pressure is applied to the contact portion. Wear becomes remarkable. That is, at the time of assembling the universal joint, so-called preloading is performed in which the bottom portion 13 of the bearing cup 11 is elastically pressed toward the end face 16 of the cross shaft 9 in order to prevent rattling of the universal joint. A large contact surface pressure acts on the contact portion between the tip end surface and the cross shaft end surface based on the preload, so that significant abrasion tends to occur in the contact portion. Such remarkable wear is not preferable because the durability of the bearing cup is impaired. The bearing cup for a universal joint of the present invention has been invented in view of such circumstances.

[0014]

The universal joint bearing cup of the present invention is made of a metal plate and is integrally formed into a cylindrical shape with a bottom, and has a cylindrical portion and a bottom portion for closing one end of the cylindrical portion. Is a bearing cup for a universal joint which is provided with a plurality of ridges formed on the inner surface of the bottom from the inside to the outside in the diametrical direction, and used with the end of the cross shaft inserted inside .

The surface of each ridge is centered in the width direction.
Arc-shaped convex surface that constitutes the tip located in the
And flat surfaces located on both sides of the convex surface. Also, the initial preload
Fkgf, the number of ridges is Z, the length of each ridge is Lmm, and the arc is
The radius of curvature of the convex surface is Rmm,
E is the Young's modulus of the metal material forming the U-shape, and m is the Poisson number.
And if

(Equation 2) The maximum contact surface pressure P _max expressed by the following is 175 kgf / mm ² or less.
is there.

Furthermore, the plane is inclined with respect to the end face of the cross shaft.
The oblique angle is 45 degrees or less.

[0017]

In the case of the universal joint bearing cup of the present invention configured as described above , the tip of the ridge is an arc-shaped convex surface,
Since the maximum contact surface pressure P _max is 175 kgf / mm ² or less,
The lubrication between the tips of the number of ridges and the end face of the cross shaft is improved from the beginning. That is, since the surface shape of the tips of the plurality of ridges is an arc-shaped convex surface, the contact between the tips of the ridges and the end face of the cross shaft is closer to line contact than surface contact.
Therefore, even when the relative rotation angle between the bearing cup and the cross shaft is extremely small, the lubricating oil is reliably fed into the contact portion between the tip portion and the inner surface, thereby preventing metal contact at the contact portion. .

Further, at the tip of each of the ridges, the radius of curvature of the portion in contact with the end face of the cross shaft is large, and the maximum contact surface pressure acting on the contact portion does not take into account the bearing by the lubricating oil film. Is also regulated to 175 kgf / mm ² or less. Moreover,
The film of the lubricating oil taken in the contact portion supports the load applied to the contact portion in a relatively wide portion by the wedge action. Therefore, the lubricating oil film hardly breaks due to this load, and even under a situation where a large load is applied to the contact portion, the metal contact can be reliably prevented.

Further, the flat portions located on both sides of the arc-shaped convex surface are provided.
The angle of inclination of the plane with respect to the end face of the cross axis is 45 degrees or less
Therefore, even when the tips of the ridges are worn out after a long period of use, a sufficient amount of lubricating oil can be taken in between the tip of each ridge and the end of the cross shaft. Therefore, the lubrication between the tips of the plurality of ridges of the bearing cup and the end face of the cross shaft is maintained in a good condition from the initial stage to the end of a long period of use.

[0020]

1 to 8 show an embodiment of the present invention.
The bearing cup 11a of the present invention is similar to the above-described conventional product.
As shown in FIG. 1, a metal plate is drawn and formed to form an integral bottomed cylindrical shape as a whole, and includes a cylindrical portion 12 and a bottom portion 13 that closes one end of the cylindrical portion 12. Then, as shown in FIG. 2, at the center of the inner surface 17 of the bottom 13,
A plurality (for example, 16 or more, 32 in the illustrated example) of the projections 21 are formed in the radial direction from the inside to the outside in the diameter direction.

As shown in FIG. 3, the cross-sectional shape of each of the ridges 21 is an arc-shaped convex surface 23 having a radius of curvature of R, and a flat surface 24 having an inclination angle of θ on both left and right sides. 24 and the shape of the mountain. The cross-sectional shape and cross-sectional area of each of the ridges 21 and 21 do not change from one end to the other end. Therefore, each of the above ridges 2
The height dimension H from which the first and second 21 project from the inner surface 17 is equal over the entire length of all the ridges 21 and 21.

Bearing cup 11a formed as described above
As shown in FIG. 1, the cylindrical portion 1
The inner peripheral surface of No. 2 is used as a raceway surface on which the rolling surfaces of the needles 15 and 15 come into contact with each other, and is fixed in a circular hole 10 formed in the yoke 7 (8). In this state, the protrusions 22 formed at the center of the end face of the cross shaft 9 abut on the plurality of protrusions 21, 21. In addition, small concave portions 18 as shown in FIG. 12 may be formed in the convex portions 22 as necessary.

In the case of the bearing cup for a universal joint according to the present invention which is configured as described above and is used in a state of being incorporated in the universal joint as described above, the tip of the plurality of ridges 21 and 21 is provided. As shown in FIG. 3, the state of contact with the convex portion 22 formed on the end face of the cross shaft 9 is closer to line contact than surface contact. Therefore, even when the relative rotation angle between the bearing cup 11a and the cross shaft 9 is extremely small, each of the ridges 21, 21
The lubricating oil is reliably fed into the contact portion between the tip of the bearing cup and the inner surface 17 of the bearing cup 11a, thereby preventing metal contact at the contact portion.

Each of the ridges 2 has a chevron section.
1, 21 have a sufficient height dimension H. Therefore, concave portions 25, 25 having a sufficient volume are formed between the adjacent ridges 21, 21, and a sufficient amount of lubricating oil stored in each of the concave portions 25, 25 is fed into the contact portion. It is.

The radius of curvature R at the tip of each of the ridges 21 and 21 in contact with the convex portion 22 is large, and the maximum contact surface pressure acting on the contact portion is restricted to 175 kgf / mm ² or less. In addition, the film of the lubricating oil taken in the contact portion supports the load applied to the contact portion in a relatively wide portion due to the wedge action. Therefore, the lubricating oil film is unlikely to be broken by this load, and even under a situation where a large load is applied to the contact portion, it is possible to reliably prevent metal contact. Therefore, even before the familiarization based on the initial wear is completed, the occurrence of metal contact is prevented, and it is possible to reliably prevent the abutting portion from being seized due to the occurrence of metal contact.

As described above, the maximum contact surface pressure is 175 kgf /
In order to restrict the radius of curvature R so as to suppress the radius of curvature to not more than mm ^{2, the} maximum contact surface pressure P _max expressed by the following equation is 175 kgf / mm.
^The condition including the radius of curvature R is regulated so as to be ² or less.

(Equation 3) In this equation, F is the initial preload (kgf), Z is the ridge 21,
The number L of the protrusions 21 is the length of the protrusions 21 and 21 (the length of a portion of the end face of the cross shaft 9 that comes into contact with the protrusion 22 in units of mm), and R is the protrusions 21 and 21 as described above. , The radius of curvature (mm) of the cross section of the arc-shaped convex surface 23 at the tip of E, E is the Young's modulus of the metal material forming the bearing cup 11a including the ridges 21 and 21 and the cross shaft 9, and m is the Poisson number (Poisson ratio is 1). / M = ν).

For example, when considering a bearing cup incorporated in a general joint for a steering shaft,
The initial preload F is about 150 kgf, the length L of each ridge 21, 21 is about 1.5 mm, and the number of ridges 21, 21 is about 30. For a bearing cup of this magnitude, the Young's modulus E is 21
The weight is about 200 kgf / mm ² and the Poisson number is about 3.33. The Young's modulus E of the cross shaft 9 is about 21200 kgf / mm ² and the Poisson number is about 3.33. Therefore, in order to set the maximum contact surface pressure P _max to 175 kgf / mm ² , the radius of curvature R may be set to about 0.4 mm. If this radius of curvature R is made larger than 0.4 mm, the maximum contact surface pressure P _max
Is smaller than 175 kgf / mm ² and conversely, smaller than 0.4 mm, the maximum contact surface pressure P _max becomes 175 kgf / mm 2.
^Greater than ² .

Therefore, when the present invention is carried out, the number, length, and radius of curvature of the tip of the cross-section are regulated while taking the above formula into account. Incidentally, the cross-sectional tip, as shown in FIG. 4 (A), even a single curved surface of curvature radius R ₁ does not change, or as shown in FIG. (B), the radius of curvature of the central portion Is R ₁ and the radius of curvature of both sides is R ₂
(<R ₁ ). When a composite curved surface, the radius of curvature R ₁ of the portion in contact at the beginning and the convex portion 22 of the cross shaft 9 end face, the maximum contact surface pressure P _max
Is regulated to be smaller than 175 kgf / mm ² .

Furthermore, the universal joint bearing cup 11 of the present invention.
In the case of a, even if the tips of the ridges 21 and 21 are worn after a long period of use, a sufficient amount of lubricating oil is applied between the tip of the ridges 21 and 21 and the end of the cross shaft. Can be captured. That is, with the use over a long period of time, each of the ridges 21,
In the case where the abrasion of the tip of 21 advances and the portion of the arc-shaped convex surface 23 having the radius of curvature R wears out, the flat surfaces 24, 24
Is in contact with the convex portion 22. Each of these planes 2
4 and 24 are uniform over the entire surface. Therefore, if the inclination angle θ of each of the planes 24, 24 is restricted to a certain value or less, even after the arc-shaped convex surface 23 is worn out, the tip surface of each of the ridges 21, 21 and the convex portion 22 can be in contact with each other. A sufficient amount of lubricating oil can be taken in between.

The inner surface 17 of the bearing cup 11a has
As shown in FIG. 5, when the ridge 21 a having a semicircular cross section is formed as shown in FIG. 5, when the amount of wear of the ridge 21 a is small as shown in FIG. Part 22
The angle θ formed between the ridge 21a and the surface of the
The lubricating oil can be efficiently taken into the contact portion between the lubricating oil and the convex portion 22.
However, as shown in FIG. 2B, as the protrusions 21a wear, the inclination angle θ increases, and the lubricating oil is not smoothly taken into the contact portion.

That is, as shown in FIG. 5, in the case of the ridge 21a whose cross section is almost semicircular, as shown in FIG.
The angle θ increases as the wear of a progresses. When the value of θ becomes larger than a certain value, the lubricating oil is not sufficiently taken into the contact portion, and the contact portion may be seized.

On the other hand, as shown in FIG. 3 and exaggeratedly shown in FIG.
As shown in FIG. 8, in the case of the ridge 21 in combination with the ridge 24, the angle θ increases with the progress of wear until the wear progresses to a certain degree, but the wear further progresses. However, the angle θ does not change with a constant value.

For example, when the universal joint for a propeller shaft as described above is considered under general conditions, for example, the height h of the arc-shaped convex surface 23 is appropriately regulated, and
By limiting the inclination angle θ of each of the planes 24 and 24 to 45 degrees or less, if the shape is such that the inclination angle θ is maintained at 45 degrees or less even when worn by 25 μm or more, the bending torque is small enough for practical use. And a universal joint that can exhibit durability and reliability. That is, the bearing cup 11a
The lubrication between the tips of the plurality of ridges 21 and the end face of the cross shaft 9 and the convex portion 22 can be maintained in a good state from the initial period to after a long period of use.

The protrusions 21, 21 need only be formed on the inner surface 17 of the bottom portion 13 of the bearing cup 11a from the inner side to the outer side in the diametrical direction, and need not necessarily be formed in the radial direction. There is no. For example, each ridge 21, 2
1 is inclined with respect to the diameter direction, or each ridge 21,
21 may be formed in a spiral direction.

[0035]

The universal joint bearing cup of the present invention is constructed and operates as described above. Therefore, even when incorporated into a universal joint having a very small joint angle, the bearing cup extends from immediately after use to after a long period of use. The lubrication between the end surface of the cross shaft and the inner surface of the bearing cup can be maintained well. Therefore, the frictional force acting between these two surfaces can be sufficiently reduced, the power loss at the universal joint portion can be suppressed low, and the durability of the cross shaft and the bearing cup can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state in which a bearing cup of the present invention is combined with an end of a cross shaft and a needle.

FIG. 2 is a view of a ridge formed on an inner surface of the bearing cup as viewed from above in FIG. 1;

FIG. 3 is an enlarged sectional view taken along the line AA of FIG. 2;

FIG. 4 is a partially enlarged sectional view showing two examples of a sectional shape of a ridge.

FIG. 5 is a cross-sectional view showing an undesired cross-sectional shape in a state in which wear does not progress and in a state after progress.

6 is a diagram showing a change in the inclination angle between the ridge surface and the mating surface as wear of the ridge having the cross-sectional shape shown in FIG. 5 progresses.

FIG. 7 is a cross-sectional view showing a preferable cross-sectional shape in which a dimension in a height direction is exaggerated as compared with a dimension in a width direction.

8 is a diagram showing a change in an inclination angle between a ridge surface and a mating surface as wear of a ridge having a cross-sectional shape shown in FIG. 7 progresses.

FIG. 9 is a half sectional view showing a propeller shaft incorporating a universal joint.

FIG. 10 is an exploded perspective view of a universal joint.

FIG. 11 is a cross-sectional view showing a state where an end of a cross shaft is inserted into a bearing cup.

FIG. 12 is a view similar to FIG. 2, showing an inner surface shape of a conventionally known bearing cup.

FIG. 13 is a view showing an end face shape of a conventionally known cross shaft.

[Explanation of symbols]

 Reference Signs List 1 propeller shaft 2 sleeve yoke 3 first shaft 4 second shaft 5 universal joint 6 rubber bush 7 first yoke 8 second yoke 9 cross shaft 10 circular hole 11, 11a bearing cup 12 cylindrical portion 13 bottom portion 14 ridge 15 Needle 16 End face 17 Inner face 18 Small recess 19 Protrusion 20 Recess 21, 21a Protrusion 22 Convex 23 Arc-shaped convex 24 Flat 25 Recess

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Makoto Fujinami 2-6-202, Takashu-cho, Mihama-ku, Chiba City, Chiba Prefecture (72) Inventor Yasuhiro Nomura 1-2-22-4, Goten, Hiratsuka-shi, Kanagawa Prefecture Wakaba Heights 2- 101 (56) References JP-A 7-20427 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16D 3/38-3/41

Claims (1)

(57) [Claims] 1. A cylindrical part, which is entirely made of a metal plate and has a bottomed cylindrical shape, and a bottom part closing one end of the cylindrical part,
A universal joint bearing cup which is provided with a plurality of ridges formed on the inner surface of the bottom from the inner side to the outer side in the diametrical direction, and used with the end of the cross shaft inserted inside. The surface of each of these ridges is composed of an arc-shaped convex surface constituting a tip located at the center in the width direction, and flat surfaces located on both sides of the arc-shaped convex surface. The initial preload is Fkgf, and the number of ridges is Z. When the length of each ridge is Lmm, the radius of curvature of the arc-shaped convex surface is Rmm, the Young's modulus of the metal material forming the bearing cup and the cross shaft including the ridge is E, and the Poisson number is m, Equation 1 The maximum contact surface pressure _Pmax expressed by the following formula is 175 kgf / mm ² or less, and the inclination angle of the flat surface with respect to the end face of the cross shaft is 45 degrees or less.