WO2006013663A1

WO2006013663A1 - Bearing for locker arm

Info

Publication number: WO2006013663A1
Application number: PCT/JP2005/008671
Authority: WO
Inventors: Rino Fukami
Original assignee: Ntn Corporation
Priority date: 2004-08-04
Filing date: 2005-05-12
Publication date: 2006-02-09
Also published as: CN101002005A; EP1801365A1; US20070289566A1; JPWO2006013663A1

Abstract

A bearing (50) for a locker arm, comprising a shaft (2) which is an inner ring fixed to the locker arm (1) interposed between the valve (9) and the cam (6) of an engine and controlling intake and exhaust, an outer ring (4) positioned on the outside of the inner ring (2) and coming into contact with the cam (6), and a plurality of needle rollers (3) positioned between the outer ring (4) and the inner ring (2). The outer ring (4) comprises a nitrogen enriched layer, and the grain number of austenitic crystal grains in the nitrogen enriched layer comes within a range exceeding #10, and micro recessed dents are formed, at random, in the outer surface (4a) of the outer ring.

Description

Rocker arm bearings

Technical field

The present invention relates to a rocker arm bearing used for a rocker arm used for opening and closing an intake valve and an exhaust valve of an automobile engine, and more specifically to a rocker arm bearing having a long peeling life. is there.

Background art

[0002] There is widely known a technology for improving fuel efficiency by reducing a friction generated in a valve operating mechanism by incorporating a rolling bearing into a rocker arm and bringing an outer ring outer diameter into rolling contact with an engine cam. When used for opening and closing the intake valve and extension valve of the above-mentioned engine, a recent rolling bearing for rocker arm is adopted a full-roller type and is often used for high speed and heavy load applications. . In the case of a full-roller type bearing without these cages, in particular, there is interference between the rollers, and the roller position is not controlled smoothly, and roller skew is likely to occur. In addition, lubricating oil is not smoothly supplied to the inside of the bearing, which may lead to poor lubrication conditions. As a result, sliding heat generation, local surface pressure increase, insufficient lubrication and the like occur. For this reason, although it has a large load capacity in calculation and the life is sufficient for the required life, surface damage (peeling, smearing, surface-originated exfoliation) and internal origin in shorter use. In many cases, mold peeling occurs and the bearing does not function.

[0003] In applications where the outer ring is in rolling contact with the cam, as in the above-mentioned bearings for rocker arms used to open and close intake valves and extension valves of the above-mentioned engine, conventionally, the outer peripheral portion of the outer ring mainly focuses on Developments have been made for the purpose of improving the outer periphery. For example, it is known that a compressive residual stress application layer by processing such as shot peening, a residual austenite-containing layer, and a hardened layer are provided in order from the surface (Japanese Patent Application Laid-Open No. 2-168 022 (Patent Document 1)). .

Patent Document 1: Japanese Patent Application Laid-Open No. 2-180222

Disclosure of the invention Problem that invention tries to solve

Among the engine parts, the cam portion has a change in rotational speed of the bearing outer ring and a sudden change in applied load due to the cam shape where the lubrication conditions are strict. do. The demand for higher speed, smaller size, and higher stress has been issued, and the use environment is becoming more severe. For this reason, even after taking the above measures, there is a problem that peeling damage occurs in the outer ring outer diameter of the bearing for the rocker arm. An object of the present invention is to provide a bearing for a rocker arm including an outer ring which can more reliably suppress peeling damage while severe conditions of use progress.

Means to solve the problem

The rocker arm bearing according to the present invention has a shaft corresponding to an inner ring fixed to a rocker arm that is interposed between a valve and a cam of an engine to adjust intake and exhaust air, and is positioned outward of the inner ring. And an outer ring in contact with the cam, and a plurality of rolling elements positioned between the outer ring and the inner ring. Then, the outer ring has a nitrogen-rich layer, the grain size number of austenite crystal grains in the nitrogen-rich layer is in the range exceeding No. 10, and the surface of the outer diameter of the outer ring has a concave with a micro concave shape random. Have.

A bearing for a rocker arm according to the present invention, which is different from the above, has a shaft corresponding to an inner ring fixed to a rocker arm which is interposed between an engine valve and a cam to adjust intake and exhaust, and an outer ring of the inner ring. It is a bearing for a rocker arm provided with an outer ring which is located on the side and in contact with a cam. In this rocker arm bearing, the outer ring has a nitrogen-rich layer, the grain size number of austenite crystal grains in the nitrogen-rich layer is in a range exceeding 10, and random micro-concave portions on the surface of the outer ring outer diameter. It has a hollow of shape. This rocker arm bearing is a type of bearing in which the inner ring and the outer ring directly contact each other without rolling elements.

[0007] In addition, the above-mentioned random micro-concave depressions of the outer ring outer diameter surface have an axial surface roughness R (L) when the surface roughness is indicated by a parameter R value (ISO international standard). Circumferential surface roughness R

The ratio R (L) / R (C) to (C) is 1.0 or less, and the surface roughness parameter Sk value is

1. Can be less than 6

According to the above configuration, the occurrence of peeling can be suppressed and the life can be extended. Here, R represents the roughness corresponding to the root mean square roughness R (old RMS) of the JIS standard. Reference in X direction Measure the height of the mountain Z over the length 1 and determine R = [(1/1) JZ ² (x) dx] ^1/2 . Just rqr

And integration ί is performed from the zero position of the reference to one. The above R (L) is axially

r qni

Taking a reference length, R (C) takes a reference length in the circumferential direction, that is, in the circumferential direction of the outer ring outer diameter surface.

qni

Ru. The fact that the ratio R (L) / R (C) is less than or equal to 1.0 means a large concave qni qni along the circumferential direction of the outer diameter surface.

It means that there is a convex, for example, it means that the groove is formed along the axial direction. The small grooves along the axial direction act as oil dams and facilitate the formation of an oil film on the outer diameter surface of the outer ring.

The parameter Sk value of the surface roughness indicates the skewness of the distribution curve of the surface asperities, and the Sk value of a symmetrical distribution such as a Gaussian distribution is zero. The above Sk value corresponds to the skewness Rsk (distortion Sk) of the roughness curve of the JIS standard, and is defined by the following equation.

Rsk = (l / R ³ ) X {(1/1) JZ ³ (x) dx}

q r

However, the integration ί is also performed up to the reference zero position force. When the parameter Sk value of surface roughness is negative, the uneven shape of the surface is, for example, a convex portion with a flat top and rounded corners, ie, a series of inverted U-shaped convex portions, and the convex portions between the convex portions This is the case when sharp valleys are located. (For reference, if the Sk value is positive, the uneven shape of the surface is, for example, pointed convex portions spaced apart, and a U-shaped valley is positioned between the pointed convex portions. In the case where the parameter Sk value is an average of less than or equal to 1.6 in both the circumferential direction and the axial direction, the shape and distribution of the surface recesses become advantageous for oil film formation depending on the processing conditions. Effect of the invention

As apparent from the above description, according to the rocker arm bearing of the present invention, it is an object of the present invention to provide a rocker arm bearing including an outer ring capable of suppressing peeling damage.

Brief description of the drawings

FIG. 1 is a view showing a rocker arm including a rolling bearing according to an embodiment of the present invention.

[Fig. 2] Fig. 2 is a cross-sectional view taken along the Π-Π line of Fig. 1.

[3] Another type of rocker including the rolling bearing in the embodiment of the present invention

FIG. FIG. 4 is a view showing yet another type of rocker arm including the rolling bearing in the embodiment of the present invention.

FIG. 5 is an enlarged view of a portion of the rolling bearing shown in FIG. 4;

FIG. 6 is a view showing a heat treatment pattern applied to at least one of the inner ring, the outer ring and the rolling elements of the rolling bearing of the present invention.

7 is a view showing a heat treatment pattern of a modification of FIG. 6 applied to at least one of the inner ring, the outer ring and the rolling elements of the rolling bearing of the present invention.

FIG. 8A is a view showing austenite grains (microstructure) of parts of the rolling bearing of the present invention.

FIG. 8B is a view showing austenite grains (microstructure) of parts of a conventional rolling bearing.

FIG. 9A is a view showing austenite grain boundaries illustrating FIG. 8A.

FIG. 9B is a view showing austenite grain boundaries illustrating FIG. 8B.

[FIG. 10] A diagram showing distribution of Sk value and R of the outer ring surface of the bearing according to the present invention example and the prior art example

qni

It is.

FIG. 11 is an example of a concavo-convex pattern in the circumferential direction of the outer ring surface of the present invention example.

FIG. 12 is a view showing an oil film formation rate of the outer ring of the example of the present invention.

FIG. 13 is a view showing an oil film formation rate of the outer ring of the conventional example.

Explanation of sign

1 rocker arm 2 inner ring (roller shaft) 3 needle roller (rolling element) 4 outer ring (roller) 4 a outer diameter surface of outer ring 5 rocker arm shaft (rotational shaft) 6 cam 7 Adjustment screw, 8 lock nut, 9 valve, 10 spring, 14 inner ring support, 19 bearing metal, 21 drive roll, 22 guide roll, 23 (3/4) "ball, 31 rolling fatigue life test

Test pieces, bearings for 50 rocker arms, inner ring incorporated in 52 rolling fatigue life tester, 53 needle rollers, outer ring incorporated in 54 rolling fatigue life tester, 55, 56 rolling fatigue life tester Load bearing member, T1 carbonitriding temperature, T2 quenching heating temperature. BEST MODE FOR CARRYING OUT THE INVENTION

Next, an embodiment of the present invention will be described using the drawings. With reference to FIGS. 1 and 2, the rocker arm 1 which is a rocking member is rotatably supported by a rocker arm shaft (rotational shaft) 5 via a bearing metal 19 or the like at a central portion. This rocker arm 1 Adjustment screw 7 is screwed on the other end lb of. The adjusting screw 7 is fixed by a lock nut 8 and abuts on the lower end thereof with the upper end of the valve 9 of the intake or exhaust valve of the internal combustion engine. The valve 9 is biased by the spring 10's force.

The rocker arm 1 is provided with a rolling bearing 50 at one end la. The shaft 2 corresponding to the inner ring of the rolling bearing 50 is supported by a bifurcated inner ring support portion 14. Both ends of the shaft 2 corresponding to the inner ring are fixed to the bifurcated inner ring support 14 by press-fitting, both-sides caulking or a locking ring. At the central portion of the outer peripheral surface of the inner ring 2, a roller 4 constituting an outer ring is supported rotatably via a needle roller 3. The needle roller 3 constitutes a bearing interposed between the inner ring 2 and the outer ring 4. That is, the rolling element (needle roller) 3 intervenes between the inner ring 2 and the outer ring 4. The axial direction of needle roller 3 is disposed parallel to the axis of the inner ring. The outer peripheral surface of the outer ring 4 is in contact with the cam surface of the cam 6 provided on the cam shaft by the biasing force of the spring 10.

Here, a rolling bearing composed of a rolling element including the inner ring 2, needle rollers 3, and an outer ring 4 is used as a full-roller bearing for a forceker arm. Generally, a roller bearing for which a cage is not used is called a full roller bearing. The above-described full-roller bearing for a rocker arm rotates in contact with the cam 6, so the pressing force and the impact force of the cam 6 act on the outer ring 4. The rocker arm of the engine according to the embodiment of the present invention is a member provided with the full roller bearing for the rocker arm. The inner ring 2 adopts a hollow shaft but may be a solid shaft.

In addition, as described above, the configuration may include rolling elements, that is, needle rollers, or a slide bearing that does not include needle rollers. That is, it may be of a type that does not include needle rollers, and the shaft corresponding to the inner ring and the outer ring are in direct contact and the inner ring and the outer ring are in sliding contact. In this case, because it is compact and has a small number of parts, it can be inexpensive and lightweight.

Outer ring 4 has a nitrogen-rich layer, and the grain size number of austenite grains in the nitrogen-rich layer is so refined as to exceed ten. Furthermore, a random micro-concave recess is formed on the surface 4a of the outer diameter of the outer ring 4, and the surface roughness is indicated by the parameter R value (ISO international standard).

qni

When the ratio of axial surface roughness R (L) to circumferential surface roughness R (C) R (L) / R (C) is 1

qni qni qni qni

Surface treatment so that the parameter Sk value of surface roughness becomes 1.6 or less. Is given.

The method of measuring the parameters Sk and R and the conditions can be illustrated as follows, for example.

qni

When measuring the surface characteristics represented by these parameters for the rolling bearing and rolling elements of rolling bearings, even measured values at one location can be relied on as representative values. Forces, for example, two locations facing in the diameter direction May be measured.

Parameter calculation standard: JIS B 0601: 1994 (Surfcom JIS 1994)

Cut-off seeds U: Gaussian

Measurement length: 5 λ

Cutoff wavelength: 0.25 mm

Measurement magnification: X 10000

Measuring speed: 0.30mm Zs

Measurement point: Center of roller

Number of measurements: 2

Measuring device: surface roughness measuring instrument Surfcom 1400A (Tokyo Seimitsu Co., Ltd.)

Next, based on FIG. 3, a bearing for a rocker arm of an engine according to another embodiment of the present invention will be described. The rocker arm rolling bearing 50 is opened between one end lb of the rocker arm 1 and the other end la and has an axle 2 corresponding to the inner ring in an inner ring hole (not shown) extending between the two side walls. It is fixed, and one end lb abuts the end of the valve 9 of the engine, and the other end la is fitted with a pivot (not shown). The rocker arm 1 provided with the pivot hole 15 is biased by the spring 10 in a predetermined direction around the pivot and receives the driving force transmitted from the cam 6 by the roller 4 constituting the outer ring, Move valve 9 against the force.

[0021] A locker arm of an engine according to still another embodiment of the present invention will be described based on FIG. 4 and FIG. In FIG. 4, the rotation shaft 5 is disposed at the central portion of the rocker arm 1 and the rocker arm 1 is pivoted around it. One end lb of the rocker arm 1 abuts on the end of the valve 9 of the engine, and the other end la abuts on the end of the interlocking rod 16. The just screw 7 has a function of adjusting the contact position between the other end la of the rocker arm and the interlocking rod 16. A rolling shaft bearing for a rocker arm (full roller bearing for a rocker arm) 50 is attached by a mounting member 17 to a hollow bearing attaching portion 16 a located at the lower end of the interlocking rod 16. The cam 6 abuts on the outer ring 4 of the full roller bearing to transmit the driving force to the connecting rod.

Also in the outer ring 4 of the bearing for rocker arm shown in FIG. 3, FIG. 4 and FIG. 5, the nitrogen-rich layer, the austenite crystal grains, and the surface roughness are the same as in the embodiment of FIG. It is formed. In order to refine the austenite grain size in the nitrogen-rich layer of the outer ring 4 so that the grain size number of the austenite grain size exceeds 10, heat treatment of the low temperature secondary hardening method described below is performed. Furthermore, when random micro-concave depressions are formed on the surface 4a of the outer diameter of the outer ring 4 and the surface roughness is represented by the parameter R value (ISO international standard), the axial surface roughness R (L) and the circumference People

qni qni

The ratio R (L) / R (C) to the facing surface roughness R (C) is 1.0 or less, and the surface roughness

qni qni qni

Surface treatment is applied so that the meter Sk value is -1.6 or less.

Next, heat treatment including carbonitriding treatment performed on the outer ring (roller) of the above-mentioned bearing for rocker arm will be described. Fig. 6 is a heat treatment pattern showing a method of performing primary hardening and secondary hardening, and Fig. 7 is a process of cooling the material to a temperature lower than the A1 transformation temperature during hardening, and then reheating and finally hardening It is a heat treatment pattern which shows a method. Both are exemplary embodiments of the present invention. In these figures, in the treatment T1, carbon is diffused into the steel base and the carbon is sufficiently melted and then cooled to below the A1 transformation point. Next, in the treatment T2 in the figure, the temperature is reheated to a temperature lower than the treatment T1, and the force is also subjected to oil quenching.

According to the above heat treatment, the crack strength is improved while carbonizing and nitriding the surface layer portion of the outer ring of the bearing for the rocker arm, rather than ordinary hardening, ie, once hardening once after carbonitriding treatment. The dimensional change rate over time can be reduced. According to the above heat treatment method, it is possible to obtain a microstructure in which the grain size of austenite grains is less than or equal to a half of the conventional one. The outer ring subjected to the above heat treatment has a long rolling fatigue property, improves the cracking strength, and can reduce the dimensional change rate over time.

Next, the microstructure of the outer ring of the bearing, particularly austenite grains, will be described with reference to FIGS. 8A, 8B, 9A and 9B. From the structures showing these austenite grain sizes, conventional austenite grain sizes and grain sizes of IS standard are No. 10 or less, and the present invention According to the heat treatment method according to No. 12, fine grains of No. 12 can be obtained. The average particle size in FIG. 9A was 5.6 m as measured by the intercept method.

[0027] Next, a method of forming the above-mentioned micro concave-shaped depression will be described. The micro concave-shaped depressions are formed by barrel polishing, and desired surface properties can be obtained by selecting the rotation speed of the polishing machine, the processing time, the work input amount, the type and size of the tip, and the like. Shot blasting etc. can also be used.

Next, based on FIG. 10, the axial direction R and circumferential direction R of the outer ring outer diameter surface of the bearing of the example of the present invention, formed by the above method, and the parameter Sk value of the surface roughness will be described. Figure

qni

In FIG. 10, corresponding measurement data of the conventional example are shown together for comparison. One feature is that the absolute value power of the negative Sk value is greater than that of the conventional example. Another characteristic is that the distribution of R has a peak at a position considerably larger than zero.

qni

Yes, it means that it was intentionally made minute bumps. As shown in FIG. 11, in the concavo-convex pattern along the circumferential direction of the outer ring outer diameter surface of the bearing of the example of the present invention formed by the above method, a deep and sharp groove is disposed between the rounded projections. It corresponds to the Sk value being less than or equal to 1.6.

The formation rate of the oil film on the outer ring outer diameter surface when the test bearing of the invention example including the above outer ring is incorporated into an actual machine test engine and tested is described based on FIG. 12 and FIG.

. As compared with the conventional example, the oil film formation rate is improved by about 20% at the start of operation as compared with the conventional example so that the two components are compared.

Example 1

Next, examples of the present invention will be described. Peeling test pieces were manufactured using JIS standard SUJ2. The test piece has an outer diameter of φ40π 40πι width L12. The manufacturing history of each test bearing is as follows.

Test Sample No. l (Invention Example): Carbonitriding temperature 850 ° C., holding time 150 minutes. The atmosphere was a mixed gas of RX gas and ammonia gas. The first quenching is performed from the carbonitriding temperature 850 ° C, and the second quenching is performed by heating the temperature at 800 ° C for 20 minutes lower than the carbonitriding temperature, and then performing the second quenching at 180 ° C for 90 minutes. I did tempering. Thereafter, special barrel polishing was carried out as surface treatment to obtain a desired finished surface. Specimen No. 2 (Comparative Example 1): Standard heat treatment was performed (in RX gas atmosphere, after heating at a heating temperature of 840 ° C., holding time of 20 minutes, quenching was performed, and then 90 ° at 180 ° C. Tempered for a minute

. ).

Test Sample No. 3 (Comparative Example 2) Carburized and Carbonated (In a mixed gas atmosphere of RX gas and ammonia gas, after heating at a heating temperature of 850 ° C. for a holding time of 150 minutes, 850 ° C.) Quenched from ₀ ° C, then tempered at 180 ° C for 90 minutes.) ₀

Table 1 and Table 2 show the results of the material examination and the peeling test of the test body manufactured by the above manufacturing method.

[Table 1]

[Table 2]

Next, the peeling test method will be described. The peeling test conditions are as shown in Table 3.

[Table 3] Peeling test conditions

Rough surface roughness When the standard heat-treated product of JIS Standard SUJ2 is used as a mating test specimen, the above-mentioned test specimens and the mating test specimen are brought into rolling contact with each other, and peeling (the fine peeling occurs The area ratio of (aggregation) was measured and it was set as peeling strength. The peel strength ratio is represented by the reciprocal of the ratio of the test specimen No. 2 of the standard heat-treated product as 1 (reference value).

The test sample No. 1 of the present invention example has a peeling strength 7 times or more that of the standard heat treated product No. 2, and the carbonitriding test product No. 3 and A peeling strength of 5 times or more could be obtained by comparison. Such a great improvement in the life is brought about by the improvement of the oil film forming ability by the fine austenite particle diameter as described above and the above-mentioned fine control of the surface asperity shape.

[0041] In the above, the force described in the embodiment and examples of the present invention The embodiments and examples of the present invention disclosed in the above are only for illustrative purposes, and the scope of the present invention is these. It is not limited to the embodiment of. The scope of the present invention is defined by the description of the claims, and further includes all modifications within the meaning and scope equivalent to the descriptions of the claims.

Industrial applicability

By using the bearing for a rocker arm of the present invention, it is possible to greatly improve the peeling resistance performance of an outer ring that comes in contact with a cam under severe conditions. Since the outer ring of such bearing for rocker arm can be obtained by performing low temperature secondary hardening treatment and barrel polishing treatment, it will be widely used for the rocker arm of automobile engine whose use condition becomes severer in the future. It is expected to be done.

Claims

Scope of claims [1] A rocker arm interposed between the engine nose (9) and the cam (6) to adjust intake and exhaust

A shaft (2) corresponding to the inner ring fixed to (1), an outer ring (4) positioned outside the inner ring (2) and in contact with the cam (6), the outer ring (4) and the inner ring In a rocker arm bearing (50) comprising: a plurality of rolling elements (3) positioned between

The outer ring (4) has a nitrogen-enriched layer, the grain size number of austenite grains in the nitrogen-enriched layer is in the range exceeding 10, and a random micro concave shape on the surface (4a) of outer ring outer diameter Bearing for a rocker arm (50) with a recess in the

[2] The surface (4a) of the outer diameter of the outer ring on which the random micro-concave depressions are formed has an axial surface roughness R (when the surface roughness is represented by a parameter R value (ISO international standard) L) and circumference

qni qni

The ratio R (L) / R (C) to the direction surface roughness R (C) is 1.0 or less, and further the parameter of surface roughness

qni qni qni

The rocker arm bearing (50) according to claim 1, wherein the data Sk value is 1.6 or less.

[3] The rocker arm (1) is rotatably supported on a rotation shaft (5) positioned between one end (la) and the other end (lb), the one end (La) has a bifurcated inner ring support (14), the inner ring (2) is fixed to the bifurcated inner ring support (14), and the other end (lb) is the engine A rocker arm bearing (50) according to claim 1, wherein the end of the valve (9) abuts.

[4] One end (lb) of the rocker arm (1) is in contact with the end of the valve (9) of the engine, and the other end (la) is fitted with a pivot, The locker according to claim 1, wherein the inner ring (2) is fixed over the inner ring holes of the two opposing side walls between one end (lb) and the other end (la) of 1). Arm bearing (50).

[5] The rocker arm (1) is rotatably supported by a rotary shaft (5) located between one end (lb) and the other end (la), and one end ( The end of the valve (9) of the engine abuts lb) and the other end (la) abuts on one end of the interlocking rod (16) which transmits the stress from the cam (6) The inner ring (2) of the rolling bearing for a rocker arm (50) is fixed to the other end of the interlocking rod (16), and the outer ring (4) is in contact with the cam (6). Rocker arm bearing (50) as described.

[6] The rocker arm bearing (50) is a full roller type needle bearing according to claim 1, Rocker arm bearing (50) as described.

[7] Rocker arm interposed between engine nose (9) and cam (6) to adjust intake and exhaust

The cam (2), which corresponds to the inner ring fixed to (1), and the cam located on the outer side of the inner ring (2)

In a bearing for a rocker arm (50) provided with an outer ring (4) in contact with (6),

[8] The surface (4a) of the outer diameter of the outer ring on which the random micro-concave depressions are formed has an axial surface roughness R (when the surface roughness is represented by a parameter R value (ISO international standard) L) and circumference

qni qni

qni qni qni

A bearing (50) for a rocker arm according to claim 7, wherein the sensor Sk value is less than or equal to 1.6.

[9] The rocker arm (1) is rotatably supported on a rotation shaft (5) located between one end (la) and the other end (lb), and the one end (La) has a bifurcated inner ring support (14), the inner ring (2) is fixed to the bifurcated inner ring support (14), and the other end (lb) is the engine A bearing (50) for a rocker arm according to claim 7, wherein the end of the valve (9) abuts.

[10] One end (lb) of the rocker arm (1) is in contact with the end of the valve (9) of the engine, and a pivot is fitted to the other end (la); The locker according to claim 7, wherein the inner ring (2) is fixed over the inner ring holes of the two opposing side walls between one end (lb) and the other end (la) of 1). Arm bearing (50).

[11] A rocker arm (1) is rotatably supported by a rotary shaft (5) located between one end (lb) and the other end (la), and one end ( The end of the valve (9) of the engine abuts lb) and the other end (la) abuts on one end of the interlocking rod (16) which transmits the stress from the cam (6) The inner ring (2) of the rolling bearing for a rocker arm (50) is fixed to the other end of the interlocking rod (16), and the outer ring (4) is in contact with the cam (6). Rocker arm bearing (50) as described.