JPH11247845A - Bearing device for roller support - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damaging to a contact part by preventing excessive bearing of the contact part and preventing application of an edge load on the contact part at the time of occurrence of misalignment. SOLUTION: Cylindrical surface parts 13, 13a are respectively provided at an intermediate part in the axial direction of an outer peripheral surface of inner diametrical side and outer diametrical side both rollers 8a, 9a. Inclined surface parts 14, 14a are provided on both sides of both of these cylindrical surface parts 13, 13a. A contact area with a mating surface is secured by the cylindrical surface parts 13, 13a. Additionally, generation of an edge load on the contact part with the mating surface is prevented by the inclined surface parts 14, 14a at the time of occurrence of misalignment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A roller support bearing device according to the present invention is incorporated in a valve train of an engine, for example, as a tappet roller bearing to reduce the friction of the valve train and thereby reduce fuel consumption during engine operation. Used to reduce the rate.

[0002]

2. Description of the Related Art For the purpose of reducing friction inside an engine and reducing a combustion consumption rate, a portion that converts rotation of a camshaft synchronized with a crankshaft into reciprocating motion of an intake valve and an exhaust valve is provided. It is common practice to incorporate tappet roller bearings. Figs. 7 and 8 show the actual opening 3-1.
1 shows a tappet roller bearing described in JP 08806.

[0005] A rocker arm 3 is provided opposite to a cam 2 fixed to a camshaft 1 which rotates in synchronization with a crankshaft of the engine and receives the movement of the cam 2. At the end of the rocker arm 3, a pair of support walls 4, 4 are provided at an interval from each other. A hollow or solid support shaft 5 made of steel is bridged between the pair of support walls 4 and 4. The ends of the support shaft 5 are not quenched and are left raw, and when the support shaft 5 is fixed, the unquenched portion is separated from the pair of support wall portions 4,
4 and crimped toward the inner peripheral surfaces of the through holes 7, 7. As described above, the roller 6 is rotatably supported around the support shaft 5 spanned between the pair of support walls 4 and the outer peripheral surface of the roller 6 2 is in contact with the outer peripheral surface.

According to the tappet roller bearing configured as described above, the frictional force acting between the rocker arm 3 and the cam 2 can be reduced, and the fuel consumption rate during engine operation can be reduced. Engine oil is supplied to the installation portion of such a tappet roller bearing at the time of engine operation. And
The engine oil lubricates between the outer peripheral surface of the cam 2 and the outer peripheral surface of the roller 6 and between the outer peripheral surface of the support shaft 5 and the inner peripheral surface of the roller 6.

It is necessary that the camshaft 1 including the cam 2 be made of cast iron or bearing steel, and the roller 6 and the support shaft 5 be made of high carbon chromium bearing steel. This method is generally used from the viewpoint of reducing material costs and processing costs while ensuring high strength. Then, by devising the gap size and the surface roughness between the peripheral surfaces of the respective members, the lubricating properties of the sliding contact portions of the respective members during operation of the engine are ensured. In order to ensure such lubrication, the support shaft 5 is made of phosphor bronze and the roller 6 is made of high carbon chromium bearing steel. Also, it has been conventionally proposed to provide an oil supply hole for supplying the engine oil to the rocker arm 3 and the support shaft 5 as described in, for example, Japanese Utility Model Laid-Open No. 4-32210. Further, the roller 6 may be made of a ceramic such as silicon nitride, for example, as disclosed in JP-A-4-15296, Japanese Utility Model Application Laid-Open No. 62-20391.
No. 1, Japanese Utility Model Laid-Open No. 3-108806, etc., have been conventionally proposed.

[0006] Even when the lubrication between the inner and outer peripheral surfaces of the roller and the mating surface is insufficient, it is possible to prevent the rolling contact or the sliding contact from causing significant damage such as wear and seizure. Various proposals have been made for such considerations. For example, JP-A-59-183007 describes that a scuffing-resistant surface treatment such as a soft nitriding treatment and an oxidation treatment is performed on both inner and outer peripheral surfaces of a roller.
Further, Japanese Utility Model Laid-Open No. 60-12604-5 discloses that a sleeve or a ring is provided between the outer peripheral surface of a support shaft for supporting a roller and the inner peripheral surface of the roller.
JP-A-8-74526 describes that a surface treatment layer for reducing friction is formed on at least one of an inner peripheral surface of a roller and an outer peripheral surface of a support shaft facing each other. .

In order to reduce the rotational resistance of the roller,
This roller may have a double structure.
As described in Japanese Patent No. 9606, it is conventionally known. Furthermore, JP-A-8-296412 discloses that
It is described that in such a structure having a roller having a double structure, the peripheral surface of one of the rollers is formed in an arc-shaped cross section whose central portion in the axial direction swells. 9 (A) and 10
(A) shows the structure described in Japanese Patent Application Laid-Open No. 8-296412. In this structure, the roller 6a
The inner diameter roller 8 and the outer diameter roller 9 are combined. The inner diameter side roller 8 has an inner peripheral surface 10 having a cylindrical surface and an outer peripheral surface 11 having a spherical convex surface. Such an inner diameter side roller 8 is rotatably supported around a support shaft 5 extending between a pair of support walls 4 provided on the rocker arm 3. The outer diameter roller 9 has a cylindrical surface on both the inner and outer peripheral surfaces, and is rotatably supported around the inner diameter roller 8. In this manner, by forming the cross-sectional shape of the outer peripheral surface of the inner diameter side roller 8 into an arcuate cross section whose central portion in the axial direction expands, the roller 6a including the inner diameter side roller 8 as shown in FIG. When the so-called misalignment occurs in which the center axis of the camshaft 1, which is the mating member with which the outer peripheral surface of the outer diameter roller 9 constituting the roller 6a abuts, is non-parallel. In addition, the so-called edge contact is prevented, in which the edge of the peripheral surface of both the inner and outer diameter rollers 8 and 9 constituting the roller 6a and the mating surface come into contact with a very small area.

[0008]

SUMMARY OF THE INVENTION
Gazette, Japanese Unexamined Patent Publication No. Hei.
03911, JP-A-3-108806, JP-A-59-183007, and JP-A-60-1260.
The inventions described in JP-A Nos. 4-5 and JP-A-8-74526 are techniques for improving lubrication between a roller and a mating surface.
Alternatively, it is a technique for preventing damage even when lubrication is defective, and cannot prevent damage when misalignment occurs. Further, the technique described in Japanese Utility Model Publication No. 46-9606 is intended to reduce the rotational resistance of the roller, but also cannot prevent damage when misalignment occurs. The technique described in Japanese Patent Application Laid-Open No. 8-296412 can prevent edge contact even when misalignment occurs, but instead, the outer peripheral surface 11 of the inner roller 8 and the inner roller Peripheral surface 12
The contact area with the contact portion is reduced, and the surface pressure applied to the contact portion is increased.

That is, the outer peripheral surface 11 of the inner roller 8
Is a convex surface having an arcuate cross section, so that the outer peripheral surface 11 and the inner peripheral surface 12 of the outer diameter side roller 9 are formed by considering the elastic deformation of both the inner diameter side and the outer diameter side rollers 8, 9. The contact is made only in a small area as shown by oblique lines in FIGS. 9B and 10B. Then, in the hatched portion, the two peripheral surfaces 11, 1
2, a large surface pressure is applied as shown in FIGS. 9 (C) and 10 (C). Applying such a large surface pressure to the peripheral surfaces 11 and 12 is not preferable because the peripheral surfaces 11 and 12 are liable to be damaged, such as galling and abnormal wear. The present invention has been made in view of such circumstances, and aims at realizing a structure that can prevent edge contact when misalignment occurs and that can suppress a rise in surface pressure at a contact portion between a peripheral surface of a roller and a mating surface. It was invented.

[0010]

The roller supporting bearing device of the present invention comprises a supporting shaft and at least one rotatably supported around the supporting shaft, similarly to the above-described conventional roller supporting bearing device. The roller is used in a state where the outer peripheral surface of the roller and the surface of another member are engaged in a contact state or the like. In particular, in the roller support bearing device of the present invention, a cylindrical surface portion parallel to the central axis of the roller is provided at the axial center of at least one of the inner and outer peripheral surfaces of the roller. A pair of inclined surface portions is provided on both sides in the axial direction sandwiching the cylindrical surface portion so that the peripheral surface forming the cylindrical surface portion is slightly inclined in a direction away from the opposing surface as the distance from the cylindrical surface portion increases. ing. In addition, the inclined surface portion referred to in the present specification includes not only a general tapered surface in which a generatrix is a straight line but also a tapered surface in which a generatrix is an arc-shaped curved surface, as is clear from embodiments described later. .

[0011]

According to the roller supporting bearing device of the present invention configured as described above, edge contact is prevented when misalignment occurs, and the surface pressure of the contact portion between the peripheral surface of the roller and the mating surface is increased. Can be suppressed. First, based on the existence of the cylindrical surface portion provided at the axial center portion of the peripheral surface of the roller, the contact area between this peripheral surface and the mating surface is secured, and the increase in the surface pressure of the contact portion between these two surfaces is suppressed. Thus, it is possible to prevent the contact portion from being damaged, such as galling and abnormal wear. Also, when misalignment occurs, based on the existence of a pair of inclined surfaces,
The contact state between the peripheral surface of the roller and the mating surface is ensured while making the center axis of the roller and the center axis of the mating member inconsistent. Since the inclination angle of the inclined surface portion with respect to the cylindrical surface portion is small, the increase in surface pressure at the boundary between the cylindrical surface portion and the inclined surface portion is small, and hardly leads to damage such as galling and abnormal wear.

[0012]

1 and 2 show a first embodiment of the present invention. A roller 6b is rotatably supported around a support shaft 5 extending between a pair of support walls 4, 4 provided at the end of the rocker arm 3, and the outer peripheral surface of the roller 6b is The cam 2 is in contact with an outer peripheral surface of a cam 2 fixed to an intermediate portion of the cam shaft 1. In the case of this example, the roller 6b is formed by combining an inner diameter side roller 8a and an outer diameter side roller 9a.

Of these, the inner diameter side roller 8a is
0 is a cylindrical surface, and the cross-sectional shape of the outer peripheral surface 11a is a mountain shape. That is, a cylindrical surface portion 13 parallel to the central axis of the inner diameter side roller 8a is provided at the center of the outer peripheral surface 11a of the inner diameter side roller 8a in the axial direction (left-right direction in FIGS. 1 and 2).
Further, a pair of inclined surface portions 14 and 14 are provided on the remaining portion of the outer peripheral surface 11a on both axial sides sandwiching the cylindrical surface portion 13. These inclined surface portions 14 and 14 are formed by a crowning process, and each of the inclined surface portions 14 and 14 is formed by the cylindrical surface portion 1.
3 is a conical convex surface that is slightly inclined in a direction in which the outer diameter decreases as the distance from the surface 3 increases. Also, each of these inclined surface portions 1
By applying post-processing such as superfinishing or barrel processing to the continuous portion between the large-diameter end portions 4 and 14 and both end portions of the cylindrical surface portion 13, these ends are formed into a curved surface having an arc-shaped cross section. ,
It continues smoothly. Such an inner diameter side roller 8a
Are rotatably supported around the support shaft 5.

The outer diameter side roller 9a is provided on the inner peripheral surface 12a.
Is a cylindrical surface, and the outer peripheral surface 15 has a mountain-like cross section, like the outer peripheral surface 11a of the inner diameter side roller 8a. That is, a cylindrical surface portion 13a parallel to the central axis of the outer diameter side roller 9a is provided at a central portion in the axial direction of the outer peripheral surface 15 of the outer diameter side roller 9a, and one side in the axial direction sandwiching the cylindrical surface portion 13a. The pair of inclined surfaces 14a, 14a are also provided by crowning. In addition, each of these inclined surface portions 14
Both the large-diameter end portions a and 14a and both end portions of the cylindrical surface portion 13a are smoothly connected to each other by curved surfaces having an arc-shaped cross section. Such an outer diameter side roller 9a is
It is rotatably supported around a.

According to the roller supporting bearing device of the present embodiment, which incorporates the roller 6b including the inner diameter roller 8a and the outer diameter roller 9a as described above, edge contact is prevented when misalignment occurs. And the roller 6
b, inner and outer peripheral surfaces 10, 11 of the inner diameter side roller 8a constituting
a and the outer surface side roller 9a can suppress an increase in the surface pressure of the contact portion between the inner and outer peripheral surfaces 12, 15 and the mating surface.

First, let us consider a state where the above-mentioned misalignment has not occurred. Inner peripheral surface 10 of the inner diameter side roller 8a
The outer peripheral surface of the support shaft 5 abuts uniformly over substantially the entire length of the inner peripheral surface 10 of the inner diameter side roller 8a, so that the abutment area between the two peripheral surfaces becomes sufficiently large, The surface pressure of the part is limited. Also, the contact portion between the outer peripheral surface 11a of the inner diameter side roller 8a and the inner peripheral surface 12 of the outer diameter side roller 9a, and the outer peripheral surface 15 of the outer diameter roller 9a and the outer peripheral surface of the cam 2 , These inner and outer diameter rollers 8
a, cylindrical surface portion 1 provided at the axially central portion of the outer peripheral surface of 9a
Based on the presence of the rollers 3 and 13a, the contact area between the inner peripheral surface 12 of the outer diameter roller 9a and the outer peripheral surface of the cam 2 is ensured.
That is, in a state where misalignment does not occur, the contact portion between the respective surfaces 12 and 13 is as shown in FIG.
It becomes wider as shown by diagonal lines. Then, a surface pressure as shown in FIG. As is clear from FIGS. 1B and 1C, according to the structure of the present embodiment, the area of the abutting portion between the respective surfaces is increased to suppress an increase in the surface pressure of the abutting portion. Damage such as galling and abnormal wear can be prevented from occurring at each contact portion.

Also, when misalignment occurs, FIG.
As shown in (A), the pair of inclined surfaces 14, 14 are provided.
a, the inner diameter side of the roller 6b,
The inner and outer peripheral surfaces of the inner and outer rollers 8a, 9a and the mating surfaces of the inner and outer rollers 8a, 9a are displaced from each other while the central axes of the outer and inner rollers 8a, 9a and the central axis of the camshaft 1 as another member are made inconsistent. To secure the contact state. At this time, the inner and outer diameter rollers 8a, 9a are slightly elastically deformed. The respective inclined surface portions 14, 14a with respect to the respective cylindrical surface portions 13, 13a.
Are slightly inclined, so that each of these cylindrical surface portions 13,
The increase in the surface pressure at the boundary between 13a and each of the inclined surfaces 14, 14a is slight. That is, each of these cylindrical surface portions 13, 13a
And the inclined surfaces 14, 14a and the mating surface are on the inner diameter side,
Considering the elastic deformation of the outer diameter side rollers 8a and 9a, as shown by oblique lines in FIG. 2B, the rollers come into contact with a wider area than the conventional structure shown in FIGS. Then, in the hatched portion, a surface pressure as shown in FIG. 2C is applied to the cylindrical surface portions 13 and 13a and the inclined surface portions 14 and 14a and the mating surface. As is clear from FIG. 2 (C), the maximum value of the surface pressure applied to the contact portion between these surfaces is low, and the contact portions are unlikely to be damaged such as galling and abnormal wear.

In practicing the present invention, the materials of the support shaft 5, the inner roller 8a and the outer roller 9a are not particularly limited. However, in consideration of durability and cost, the support shaft 5 is made of steel (in particular, the inner roller 8a).
It is preferable that the intermediate portion (which faces the inner peripheral surface 10) is quenched and cured. Also, it is desirable that the outer diameter side roller 9a is also made of hardened and hardened steel. On the other hand, the inner roller 8a may be made of quenched and hardened steel, but copper or a copper alloy having self-lubricating properties can also be preferably used.
It is also preferable from the standpoint of improving durability that one or both of the inner diameter side roller 8a and the outer diameter side roller 9a be subjected to a surface treatment for improving lubrication and abrasion resistance.

The angle of inclination of each of the inclined surfaces 14 and 14a is determined according to the conditions of use, but is set to 10 degrees or less when used as a tappet roller bearing for an automobile. For example, at a position closer to the center in the axial direction by 1 mm from the axial end surface of each of the inner and outer diameter rollers 8a and 9a,
The drop amount of each of the inclined surface portions 14 and 14a (the cylindrical surface portion 13,
(The distance between the imaginary cylindrical surface and each inclined surface portion 14, 14a in the diametric direction when it is assumed that 13a is extended) is 1 to 20.
The angle of inclination is regulated so as to be about μm. In addition, each of the inclined surface portions 14 and 14a has a radius of curvature of 5
Approximately 00 to 10000 mm, and the cylindrical surface portions 13 and 13a
It is also possible to form a curved surface that continues smoothly from the end of. Also in this case, the above-mentioned amount of fall is regulated in the above-mentioned range. The ratio of each of the cylindrical surface portions 13 and 13a to the entire length of both the inner and outer diameter rollers 8a and 9a is designed by design within a range of 40 to 70%.

Next, FIG. 3 shows a second embodiment of the present invention.
An example is shown. In the case of the present example, a cylindrical surface portion 13b is formed at an axially intermediate portion of the inner peripheral surface 10a of the inner diameter side roller 8b constituting the roller 6c, and the cylindrical surface portion 13b is sandwiched by the remaining portion of the inner peripheral surface 10a. A pair of inclined surfaces 14b, 1
4b. Further, the outer diameter side roller 9b not only forms the cylindrical surface portion 13a and the inclined surface portions 14a, 14a on the outer peripheral surface 15, but also forms the cylindrical surface portion 13c and the inclined surface portions 14c, 14c on the inner peripheral surface 12a. These respective inclined surface portions 14a, 14b, 14c are formed on the inner peripheral surfaces 10a, 12
The inclined surface portions 14b and 14c formed on the outer peripheral surface 15 are inclined in a direction in which the inner diameter increases as the distance from the cylindrical surface portions 13b and 13c increases.
a and 14a are inclined in a direction in which the outer diameter decreases as the distance from the cylindrical surface portion 13a increases. Of such inclined surface portions 14a, 14b, 14c, inner peripheral surfaces 10a, 12a
The inclined surface portions 14b and 14c formed in the above can be formed by plastic working called "slope processing". Also in the case of this example having such a structure, similarly to the case of the first example described above, the area of the contact portion between the surfaces is increased to suppress the increase in the surface pressure of each contact portion. Damage such as galling and abnormal wear can be prevented from occurring at each contact portion.

FIG. 4 shows a third embodiment of the present invention.
An example is shown. In the case of this example, the inclined surfaces 14, 14 are formed not only on the inner peripheral surface 10a but also on the outer peripheral surface 11a of the inner diameter side roller 8c constituting the roller 6d. Other configurations and operations are the same as those in the above-described second example.

Next, FIG. 5 shows a fourth embodiment of the present invention.
An example is shown. In the case of this example, the same roller as the above-described third example is used as the inner diameter side roller 8c constituting the roller 6e, and the same one as the above-described first example is used as the outer diameter side roller 9a. . Furthermore, in the case of this example,
An intermediate roller 16 is provided between the inner diameter roller 8c and the outer diameter roller 9a, and the roller 6e has a three-phase structure. The intermediate roller 16 is provided on the outer diameter side roller 9a.
Similarly to the above, the inner peripheral surface 17 is a cylindrical surface, the cylindrical surface portion 13d is provided at the axially intermediate portion of the outer peripheral surface 18, and the inclined surface portions 14d, 14d are provided at both axial ends. In this case, the number of sliding surfaces provided inside the roller 6e is increased, the amount of sliding on each sliding surface is reduced, the lubrication conditions are improved, and wear can be reduced. Other configurations and operations are the same as those in the above-described examples.

FIG. 6 shows a fifth embodiment of the present invention.
An example is shown. In this example, a single roller 6f is used. A cylindrical surface portion 13e is provided at an axially intermediate portion of the inner peripheral surface 19 of the roller 6f, and an inclined surface portion 14 is provided at both axial end portions.
e and 14e are provided respectively. Further, a cylindrical surface portion 13f is provided at an axially intermediate portion of the outer peripheral surface 20, and inclined surface portions 14f, 14f are provided at both axial end portions. In the case of this embodiment as well, similarly to the case of each of the above-described embodiments, the area of the abutting portion between the opposing surfaces is increased to suppress the increase in the surface pressure of each abutting portion. Damage such as galling and abnormal wear can be prevented from occurring at the contact portion.

[0024]

Since the roller supporting bearing device of the present invention is constructed and operates as described above, it is possible to manufacture the cam follower device which can be manufactured at low cost without particularly increasing the assembling precision and has excellent durability. It can contribute to realization.

[Brief description of the drawings]

FIGS. 1A and 1B show a first example of an embodiment of the present invention in a state where no misalignment has occurred; FIG. 1A is a cross-sectional view, and FIG. (A) is a diagram viewed from below, and (C) is a diagram showing a surface pressure distribution of a contact portion.

FIG. 2 shows a first example of an embodiment of the present invention in a state where misalignment has occurred, and FIG.
(B) is a view of the contact portion viewed from below (A) to represent the contact area, and (C) is a diagram showing the surface pressure distribution of the contact portion.

FIG. 3 is a sectional view showing a second example of the embodiment of the present invention.

FIG. 4 is a sectional view showing the third example.

FIG. 5 is a sectional view showing the fourth example.

FIG. 6 is a sectional view showing the fifth example.

FIG. 7 is a partially cutaway plan view of the tappet roller bearing.

FIG. 8 is a sectional view taken along line XX of FIG. 7;

9A and 9B show an example of a conventional structure in which no misalignment has occurred. FIG. 9A is a cross-sectional view, and FIG. 9B shows a contact area. View from below,
(C) is a diagram showing a surface pressure distribution of the contact portion.

10A and 10B show an example of a conventional structure in a state where misalignment has occurred. FIG. 10A is a sectional view, and FIG. 10B shows a contact area. The view I saw,
(C) is a diagram showing a surface pressure distribution of the contact portion.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Camshaft 2 Cam 3 Rocker arm 4 Support wall part 5 Support shaft 6, 6a, 6b, 6c, 6d, 6e, 6f Roller 7 Through-hole 8, 8a, 8b, 8c Inner diameter roller 9, 9a, 9b Outer diameter side Roller 10, 10a Inner peripheral surface 11, 11a Outer peripheral surface 12, 12a Inner peripheral surface 13, 13a, 13b, 13c, 13d, 13e, 13
f Cylindrical surface part 14, 14a, 14b, 14c, 14d, 14e, 14
f Inclined surface part 15 Outer peripheral surface 16 Intermediate roller 17 Inner peripheral surface 18 Outer peripheral surface 19 Inner peripheral surface 20 Outer peripheral surface

Claims (1)

[Claims] 1. A support shaft and at least one roller rotatably supported around the support shaft. The roller is used in a state where an outer peripheral surface of the roller is engaged with a surface of another member. In a roller supporting bearing device, at least one of the inner and outer peripheral surfaces of the roller is provided at an axially central portion with a cylindrical surface parallel to the central axis of the roller, and the cylindrical surface is provided with the cylindrical surface. On both sides in the axial direction, a pair of inclined surface portions are provided, each of which is slightly inclined in a direction in which a peripheral surface forming the cylindrical surface portion is separated from an opposing surface as the distance from the cylindrical surface portion is increased. Roller supporting bearing device.