JP2601459Y2 - Bearing device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device for supporting a roller of a cam follower with a roller and a pinion of a planetary gear of an industrial machine such as an automobile, and particularly to an improvement of the shaft thereof.

[0002]

2. Description of the Related Art A shaft for bearing a hollow rotary member between a pair of yoke-shaped holding members via a needle rolling element rolling on the inner surface of the hollow portion is held, and the shaft is attached to the holding member. There is a bearing device in which both ends are inserted into an opened shaft hole and an end face is fixed by caulking. Such bearing devices are used for roller supports such as roller rockers and tappet rollers for valve drive cam followers of automobile engines and the like, and planetary gear pinion supports for transmissions.

In a conventional roller drive rocker for driving a valve, a hardened layer is provided on the outer peripheral surface of a hollow cylindrical steel roller shaft by induction hardening only on a rolling surface of a needle rolling element, and both ends are soft. There is known a configuration in which the end portions are caulked and fixed to shaft holes in the outer surfaces of the pair of yoke-shaped holding members as they are.

[0004] Further, regarding a planetary gear for transmission, a solid hardened layer formed by carburizing and quenching is provided on the outer peripheral surface on which the needle rolling element rolls except for both ends of a solid cylindrical steel pinion shaft, Both ends were made soft by being carbon-proofed, and the pinion shaft was fixed to the support member by caulking both end surfaces of the yoke-like support member.

[0005]

In recent years, in order to improve the fuel efficiency of automobiles and to reduce the size and weight of general industrial machines, the above-mentioned cam followers with rollers and planetary gears also need to be downsized. It is expected that the roller shaft and the pinion shaft will be made hollow to reduce the weight, reduce the inertia force in the swing of the cam follower and the revolution of the planetary gear, and contribute to the improvement of energy efficiency.

It is preferable to reduce the thickness of these hollow shafts for the above purpose. However, since the thin shafts have low rigidity, the load received by the rollers and gears is applied to the rolling surface via the needle rolling element. The hollow shaft repeatedly bends.
In particular, in the area where the end of the needle roller is pressed against the rolling surface,
Since a large repetitive shear stress acts, it tends to be a starting point of fatigue fracture in long-term use.

Although it is easy to use a steel pipe as a raw material for manufacturing a hollow shaft, the cost of the raw material is high, and it is difficult to obtain a steel pipe satisfying the required material and wall thickness. Therefore, as shown in FIG. 3, a punch having a predetermined outer diameter is press-fitted from one end surface of a column (FIG. A) obtained by cutting a bar or wire rod to form a bottomed cylindrical body (FIG. B). Then, the bottom was punched and opened with a piercing punch (C in the same figure) to form a hollow cylindrical shaft having counterbore end faces at both ends, and a hardened layer 16 by induction hardening / tempering was provided on the outer peripheral surface (D in the same figure). .

The above-described method of molding from a wire requires a two-step press-fitting operation, and requires a long punch. Therefore, the punch is liable to break during many uses, and the punch is significantly worn and the life of the punch is reduced. There was a problem with workability such as being short.

The present invention has been made in view of the above problems, and has as its object to provide a bearing device provided with a lightweight shaft having a high rigidity, an excellent rolling life, and a hollow portion that is easy to drill. .

[0010]

According to the bearing device of the present invention, both ends of a shaft that supports a rotating member via a needle rolling element are inserted into shaft holes of a pair of opposed plate-shaped holding members. In a bearing device which is fixed by caulking and holds the rotating member between the holding members, the shaft has hollow portions opened on both sides of a counterbore end surface, and the hollow portion is formed at a substantially central portion in the axial center direction. It is characterized in that a partition part to be separated is integrally provided, and an induction hardened hardened layer is provided on the outer peripheral surface of the shaft except for both ends.

[0011] In the bearing device of the present invention, the shaft has C of 0.60 to 0.85%, Si or Al alone or Si and Al in a total amount of 0.5 to 1.5%. , Bearing devices formed of steel comprising:

[0012]

The shaft supporting the rotating member of the bearing device of the present invention has hollow portions opened on both ends on both sides, so that the shaft mass can be reduced and the shaft is integrally provided substantially at the center in the axial direction. The partition wall portion increases rigidity against bending and bending of the shaft, and increases fatigue strength against repeated load on the shaft provided by the needle rolling element. In the case of an application of a bearing device having a large load on a shaft, the thickness can be appropriately adjusted so as to increase the thickness of the partition wall portion.

Since the shaft has an induction hardened layer on the outer peripheral surface except at both ends, the shaft compensates for the abrasion resistance against the rolling of the needle rolling element and ensures the rolling life. It is unhardened and soft, has high toughness, and has high impact strength and fatigue strength. Both ends are softened as they are unquenched and have a counterbore end face, so that caulking on the holding member can be facilitated.

If the punch is press-fitted from one end face of the steel material of the solid columnar body or simultaneously from both ends, a hollow section is formed on both ends and a hollow end face is formed, and a partition section is formed between the hollow sections. Since the punch is formed, the punch press-in length can be shortened compared to the conventional method, the frequency of punch breakage and wear loss in the mass production process can be reduced, and there is no need to open holes penetrating both ends. Can be improved.

The material for the shaft is used because the medium-carbon structural steel having the above composition is easy to cold work and has quench hardening ability by induction hardening. Since the composition steel of the present invention contains 0.60 to 0.85% of C, it has both workability and hardenability. Furthermore, Si or A
1 alone or 0.5 to 1.5% in total of Si and Al
Is that Si and Al exhibit temper softening resistance, reduce the decrease in hardness even by tempering at a temperature higher than the normal tempering temperature, and adjust the amount of retained austenite in the hardened layer to thereby improve the toughness of the surface layer. Also, even if the shaft temperature rises during use of the bearing device, the degree of softening of the hardened layer is small and the wear resistance, especially the peel life, is improved. Si is 1.
If it is more than 5%, cold workability is impaired, so that it is not preferable for the hollow shaft of the present invention.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the bearing device of the present invention will be described below with reference to the drawings.

FIG. 1A is a cross-sectional view of a roller support portion on the front side of a rocker arm, which is a cam follower for driving a valve, which is an example of a bearing device. Roller 31 slidingly in contact with a cam surface of a rotating cam (not shown) between yoke-shaped roller support members 2 and 2
A large number of needle rollers 4 to be housed and interposed on the inner peripheral surface of the roller 31 are held, and inside the arranged needle rollers 4,
The roller shaft 1 that is in sliding contact with the needle rollers 4 is disposed, and both end portions 12 of the roller shaft 1a are inserted into shaft holes 21 and 21 provided in the roller support members 2 and fixed by caulking. .

FIG. 1B is a cross-sectional view of a pinion support portion of a planetary gear, which is another example of the bearing device. The pinion support portion is connected to a shaft of a parent gear (not shown). A pinion 32 is provided between a pair of yoke-shaped pinion holding members 2 and 2 provided on the side of the pinion shaft 1 b via a needle roller 4.
And both ends of the pinion shaft 1b are caulked and fixed to the shaft holes 21 and 21 of the pinion holding members 2 and 2, respectively.

The roller shaft 1a and the pinion shaft 1 shown in FIG.
2B are shown in FIGS. 2A and 2B, respectively. When the roller shaft 1a is described with reference to FIG.
Has a cylindrical surface, and both end portions 12 and 12 are formed as tapered counterbore end surfaces 11, and hollow portions 17 and 17 are provided coaxially with the outer peripheral surface in the axial direction from both end surfaces 11 and 11, respectively. The ends of each of the hollow portions 17 are formed as a partition wall 18 provided integrally with the cylindrical body portion, and the partition wall portion 18 has a desired thickness at a substantially central portion in the axial direction.

The shaping of the shaft 1 is made of the above medium carbon steel,
5% C, 0.8% Si, 0.3% Mn, 0.020P,
This is the result of cold working of steel having a composition of 0.015%, 0.030% Al or the like. A punch is press-fitted from one end surface of a steel material of a solid column, and first, one hollow portion 17a and a tapered surface are formed. 11a, and then the other hollow portion 17b and the tapered surface 11b are similarly formed from the other end surface.
To form

The length of the hollow portion 17 of the shaft according to the present invention is about half the length of the hollow portion of the conventional hollow shaft having no partition wall, and the length of the punch may be short. Further, if the punch press-fitting operation is performed simultaneously from both ends, the position and the thickness of the partition wall portion 18 can be accurately adjusted, and the shaping of the shaft is completed in one punch press-fitting step.

The formed shaft 1 is provided on its outer peripheral surface, that is,
The contact surface where the needle rollers 4 roll is 850 in the high frequency coil.
The surface layer is quenched and hardened by water quenching immediately after induction heating to a temperature of less than a few seconds for a very short time, and then tempered to 180 ° C. to provide a hardened layer 16. The surface hardness of the hardened layer 16 after polishing is Rockwell C hardness _HRC58.
The above is secured. Both ends 12, 12 are kept soft without quenching and hardening by suppressing the temperature rise during high-frequency heating.

As shown in FIG. 1A, the roller shaft 1a is fixed to the roller holding member 22 by inserting the roller shaft 1a into the shaft holes 21 and 21 of the pair of roller holding members, and the both ends 12 and 12 slightly. When the counterbore end face 11 is pressed with a punch having a tapered surface obtusely smaller than the taper angle of the counterbore end face 11, the peripheral portion 13 of the counterbore end face 11 is pressed.
Is expanded to form an enlarged edge portion 14 around the shaft hole 21 on the outer surfaces 21 and 21 of the roller holding members 2 and 2 and swaged.

In the above, the roller shaft 1a and the roller holding member 2
Although the crimping fixation has been described, the long pinion shaft 1b shown in FIG. 2B is similarly formed, and is crimped to the pinion holding member 2.

[0025]

The shaft of the bearing device of the present invention has a hollow portion and is formed in a central portion in the axial direction between the hollow portions on both sides. The rigidity of the shaft is high, the fatigue strength against repeated loads of the rolling elements is excellent, and the life and reliability of the bearing device are improved.

Since the life of the punch can be extended to form a hollow portion from a solid steel material and the piercing step can be omitted, the workability can be improved and the cost can be effectively reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a roller holding portion of a cam follower with a roller, which is an embodiment of the bearing device of the present invention (A), and a cross-sectional view of a pinion holding portion of a planetary gear (B).

FIG. 2 is a sectional view of a roller shaft (A) and a pinion shaft (B).

FIG. 3 is a cross-sectional view (A, B,
C, D).

[Explanation of symbols]

 Reference Signs List 1 shaft 11 counterbore end face 12 end 16 hardened layer 17 hollow 18 partition wall 2 roller holding member 21 shaft hole 3 rotating member 31 roller 32 pinion 4 needle rolling element 81 locator arm main body 82 connecting member

Continuation of the front page (56) References JP-A-59-89713 (JP, A) JP-A-63-153239 (JP, A) JP-A-57-90415 (JP, A) JP-A-63-153239 (JP) JP-A-2-102302 (JP, A) JP-A-2-204604 (JP, A) JP-A-4-141521 (JP, A) JP-A-4-314842 (JP, A) 4-339111 (JP, A) Fully open Hei 3-63703 (JP, U) Really open 63-133851 (JP, U) Really open 56-165102 (JP, U) Really open 58-58,558 (JP, U.S.A.) U) Japanese Utility Model Hei 4-93509 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) F16C 3/02 C22C 38/00 301 C22C 38/06 F16H 53/06

Claims (3)

(57) [Scope of request for utility model registration] An end of a shaft that supports a rotating member via a needle rolling element is fixed by caulking by inserting both ends of a shaft into a pair of opposed plate-like holding members. In a bearing device holding a member, the shaft is configured such that C is 0.60 to 0.85%, Si or Al is used alone, or Si and Al are used in a total amount of 0.5 to 1.5%.
%, And the shaft is formed on both sides with hollow portions that are open to the counterbore end surface, and a partition portion that separates the hollow portion is provided substantially at the center in the axial direction. A bearing device which is provided integrally and has an induction hardened hardened layer except for both end portions on an outer peripheral surface of a shaft. 2. The bearing device according to claim 1, wherein the rotating member is a hollow roller, and the bearing device is a cam follower with a roller. 3. The bearing device according to claim 1, wherein the rotating member is a gear having a hollow portion, and the bearing device is a planetary gear.