JP2012107693A - Rolling bearing device for cam-follower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce torque of the whole rolling bearing, by restraining frictional resistance between rollers, by reducing a part adjacent in a state of mutually contacting the mutual rollers, in a rolling bearing device for a cam-follower.SOLUTION: An outer peripheral surface of the rollers includes a crowning part of applying crowning work to both ends, and a straight line part formed between the crowing parts and having the outer peripheral surface formed in substantially parallel to the axis. Arrangement of the rollers is constituted by combining single-row needle-like rollers 42 (single-row rollers) formed in the substantially same length as the width length in the axial direction of the rollers, and double-row needle-like rollers 44 (double-row rollers) adjacent to the single-row needle-like roller 42 and constituting a plurality of rollers having the length shorter than the single-row needle-like roller 42 in the axial direction.

Description

  The present invention relates to a rolling bearing device for a cam follower. Specifically, the inner peripheral surface of the cylindrically formed roller is defined as an outer ring raceway surface, and the outer peripheral surface of a shaft body inserted into the roller is defined as an inner ring raceway surface. A plurality of rollers are provided between the outer ring raceway surface and the inner ring raceway surface. The present invention relates to a rolling bearing device for a cam follower, in which a plurality of rollers are provided adjacent to each other so as to be freely rotatable, and a roller is rotatable around an axial center by a cam being brought into rolling contact with an outer peripheral surface of the roller.

2. Description of the Related Art Conventionally, cam followers used for engine valve mechanisms of automobiles and other various cam mechanisms are known.
As this cam follower, technical disclosures in Patent Document 1 and Patent Document 2 are made. In the disclosures in Patent Document 1 and Patent Document 2, the inner peripheral surface of a roller formed in a cylindrical shape is an outer ring raceway surface, and the outer peripheral surface of a shaft body inserted into the roller is an inner ring raceway surface. A cam follower is shown in which a plurality of rollers are provided adjacent to the raceway surface so as to be freely rollable. Then, the roller is rotatable about the shaft center by rolling the cam on the outer peripheral surface of the roller, and the rotating cam is brought into contact with the flat outer peripheral surface of the roller so that the roller itself is It is configured to reciprocate in a predetermined direction.

JP 2004-036781 A JP 2004-204896 A

The cam follower shown here is of the so-called full roller type in which no cage is formed between the cylindrical rollers arranged between the outer ring raceway surface and the inner ring raceway surface.
Therefore, between the outer ring raceway surface and the inner ring raceway surface, the rollers are adjacent to each other in a state of contact with each other, and when the rollers roll, frictional resistance is generated at the contacted portion, which increases the torque of the cam follower. Had the problem of becoming.

  Therefore, as a result of diligent study, the present inventor has achieved that if the roller in this cam follower rolling bearing device can reduce the frictional resistance between the rollers by reducing the number of adjacent parts in contact with each other. It was noted that the torque of the entire bearing can be reduced.

  Thus, the present invention has been devised in view of such points, and the problem to be solved by the present invention is that the inner peripheral surface of a roller formed in a cylindrical shape is an outer ring raceway surface. An outer peripheral surface of the shaft inserted into the roller is defined as an inner ring raceway surface, and a plurality of rollers are provided adjacent to and rollable between the outer ring raceway surface and the inner ring raceway surface. In a rolling bearing device for a cam follower that is configured such that the roller is rotatable about its axis by the rolling contact of the cam, the number of adjacent portions in a state where the rollers are in contact with each other is reduced. The purpose is to suppress frictional resistance and reduce the torque of the entire rolling bearing.

In order to solve the above problems, the rolling bearing device for a cam follower of the present invention takes the following means.
First, a rolling bearing device for a cam follower according to a first aspect of the present invention has a cylindrical body (20) whose inner peripheral surface is an outer ring raceway surface (20b), and a shaft body that is inserted into the roller (20). An outer peripheral surface of (30) is an inner ring raceway surface (30b), and a plurality of rollers (42, 44) are adjacently allowed to roll between the outer ring raceway surface (20b) and the inner ring raceway surface (30b). In a rolling bearing device for a cam follower that is provided and configured such that the roller (20) is rotatable about an axis by a cam (60) being brought into rolling contact with an outer peripheral surface of the roller (20). The outer peripheral surfaces of the rollers (42, 44) are formed between the crowning portions (42a, 44a) having the crowning process at both ends and the crowning portions (42a, 44a), and the outer peripheral surfaces are substantially parallel to the axis. The formed straight portion (42b, 4b), and the arrangement of the rollers (42, 44) includes a single row roller (42) formed to have a length substantially the same as the width in the axial direction of the roller (20), and the single row roller. (42) A structure in which a plurality of rollers having a shorter length are combined with a double row roller (44) configured in the axial direction.

According to the first aspect of the invention, the outer peripheral surface of the roller includes a crowning portion that is crowned at both ends, and a linear portion that is formed between the crowning portions and the outer peripheral surface is formed substantially parallel to the axis. I have.
The roller arrangement is a combination of a single row roller formed in substantially the same length as the width in the axial direction of the roller and a double row roller in which a plurality of rollers having a shorter length than the single row roller are formed in the axial direction. It has been configured. Thereby, since the linear part of a double row roller becomes a structure which each partially contacts the linear part of a single row roller, the site | part which the rollers contacted decreases and the frictional resistance between rollers can be suppressed. Therefore, it is possible to reduce the torque of the entire rolling bearing.
Further, when viewed from the strength side of the rolling bearing, a single row roller having a long straight portion is more effective. This rolling bearing device for a cam follower has a configuration in which double row rollers and single row rollers are combined in consideration of durability. Therefore, it is possible to suppress the frictional resistance between the rollers without impairing the durability of the rolling bearing as compared with the configuration of only the double row roller bearing.

  Next, in the rolling bearing device for a cam follower according to the second invention, in the first invention described above, the arrangement of the rollers between the outer ring raceway surface (20b) and the inner ring raceway surface (30b) is the single row roller. (42) and double row rollers (44) are arranged alternately.

  According to the second aspect of the invention, the arrangement of the rollers between the outer ring raceway surface and the inner ring raceway surface is a configuration in which single row rollers and double row rollers are alternately arranged. In other words, the function of suppressing the frictional resistance between the rollers can be exhibited better without impairing the durability of the rolling bearing.

  Next, a rolling bearing device for a cam follower according to a third aspect of the present invention is the above-described double-row roller (44) between the double-row rollers (44) in the axial direction in the second or third invention described above. 44) A ball (50) having the same diameter as that of 44) is arranged and configured.

  According to the third aspect of the invention, balls having the same diameter as the double row rollers are arranged between the double row rollers in the axial direction. Thereby, since the part which the linear part and ball | bowl of a single row roller contact becomes a point contact, the frictional resistance between a single row roller and a double row roller can be suppressed further.

  According to the present invention, the outer ring raceway is formed by taking the means of each of the above inventions so that the inner circumferential surface of a cylindrically formed roller is the outer ring raceway surface, and the outer circumferential surface of the shaft body inserted into the roller is the inner ring raceway surface. A plurality of rollers are provided adjacent to each other between the surface and the inner ring raceway surface so as to be freely rotatable, and the roller is configured to be rotatable about its axis by rolling the cam on the outer peripheral surface of the roller. In such a roller bearing device for a cam follower, it is possible to reduce the frictional resistance between the rollers by reducing the number of adjacent portions in a state where the rollers are in contact with each other, thereby reducing the torque of the entire rolling bearing.

It is a side view which shows the rocker arm as a rolling bearing apparatus for cam followers which concerns on Example 1 of this invention. It is the schematic sectional drawing which showed the rocker arm as a rolling bearing apparatus for cam followers which concerns on Example 1 of this invention. It is the whole perspective view which showed the rocker arm as a rolling bearing apparatus for cam followers concerning Example 1 of the present invention. It is the enlarged view which showed the roller simple substance of the rocker arm as a rolling bearing apparatus for cam followers which concerns on Example 1 of this invention. It is the whole perspective view which showed the rocker arm as a rolling bearing apparatus for cam followers concerning Example 2 of the present invention. It is the enlarged view which showed the roller and ball | bowl of the rocker arm as a rolling bearing apparatus for cam followers concerning Example 2 of this invention.

  A mode for carrying out the present invention will be described in accordance with an embodiment.

  A first embodiment of the present invention will be described with reference to FIGS.

The rolling bearing for a cam follower according to the present invention is used for an engine valve mechanism of an automobile or other various cam mechanisms, for example.
Here, as a rolling bearing for a cam follower according to an embodiment of the present invention, a rocker arm 10 arranged at a predetermined location of an engine valve mechanism of a vehicle will be described with reference to the drawings.
As shown in FIG. 1, a rotating cam 60 is disposed at a predetermined position of the engine valve mechanism, and the rocker arm 10 is disposed at a position where it abuts against the cam 60.
The rocker arm 10 includes a roller 20 that a cam 60 contacts and rolls, and a pair of opposing walls 14 and 16 that face each other via the roller 20.
The body 12 is formed by the opposing walls 14 and 16 and the connecting walls 18 and 19 connecting the opposing walls 14 and 16 on both sides in the longitudinal direction. One connecting wall 18 is used as a pivot receiving portion with which the upper end portion of the lash adjuster 62 abuts, and the other connecting wall 19 is used as a valve stem receiving portion into which the upper end portion of the valve stem 64 is fitted.
Support holes 14a and 16a are concentrically formed in the opposite walls 14 and 16 at intermediate portions in the longitudinal direction, respectively. A roller 20 is disposed between the opposing walls 14, 16, and the roller 20 is formed with a shaft insertion hole 20 a having a circular shape in a side view penetrating in the axial direction at a central portion in the radial direction. A cylindrical surface is formed on the outer peripheral surface of the roller 20 to which the cam 60 rolls.
In the case where the axial width of the roller 20 is smaller than the axial width of the cam 60, the outer peripheral surface of the roller 20 may be crowned. When the outer peripheral surface of the roller 20 is crowned, the contact pressure distribution of the roller 20 with respect to the cam 60 can be made uniform, and the edge load can be suppressed, which is advantageous in preventing uneven wear of the cam 60. Become.

As shown in FIG. 2, the shaft body 30 is bridged over the support holes 14a and 16a so that both end portions 30a are supported in a non-rotating manner. The shaft body 30 is formed in a solid cross section.
The shaft body 30 is crimped so that each end 30a expands in the radial direction in a state where the shaft body 30 is inserted and passed through the both support holes 14a and 16a, and is thereby pressed against the peripheral walls of the support holes 14a and 16a. Are supported by the opposing walls 14 and 16 in a non-rotating manner.

The roller 20 disposed on the outer periphery of the shaft body 30 has an inner peripheral surface as the outer ring raceway surface 20b, an outer peripheral surface of the shaft body 30 as the inner ring raceway surface 30b, and between the outer ring raceway surface 20b and the inner ring raceway surface 30b. A plurality of needle rollers 42, 44 are arranged adjacent to each other so as to roll around the shaft body 30. The rolling bearing composed of the roller 20, the shaft body 30, and the needle rollers 42 and 44 is a full roller type having no cage.
The roller 20 rotates about the axis when the cam 60 is brought into rolling contact with the outer peripheral surface of the roller 20.

  In the rocker arm 10, the rotation of the cam 60 in conjunction with the rotation of the crankshaft (not shown) causes the roller 20 with which the cam 60 abuts to rotate about the shaft 30 and the body 12 is centered on the pivot receiving portion. It swings and opens and closes a valve (not shown) provided in a cylinder head (not shown).

As shown in FIG. 3, two configurations of needle rollers 42 and 44 are arranged between the outer ring raceway surface 20 b of the roller 20 and the inner ring raceway surface 30 b of the shaft body 30.
The needle rollers 42 are configured as a single row of needle rollers 42 formed to have substantially the same length as the width of the roller 20 in the axial direction. The single row needle rollers 42 correspond to the “single row rollers” in the present invention.
The needle rollers 44 are double-row needle rollers 44 in which a plurality of rollers having a shorter length than the single-row needle rollers 42 (single row rollers) are formed in the axial direction. The double row needle rollers 44 correspond to the “double row rollers” in the present invention.
Here, the arrangement of the rollers is as follows: a single-row needle roller 42 (single-row roller) and a double-row needle roller 44 (double-row) adjacent to the single-row needle roller 42 (single-row roller). Single row needle rollers 42 (single row rollers) and double row needle rollers 44 (double row rollers) are alternately arranged.

As shown in FIG. 4, the single-row needle rollers 42 (single-row rollers) are rollers formed to have substantially the same length as the width of the roller 20 in the axial direction.
In each single row needle roller 42 (single row roller), the outer circumferential surface within the effective roller length in the axial direction is distributed to both sides at a predetermined length, that is, a substantially uniform length, and crowned to the outer circumferential surface. It has a crowned portion 42a that has been processed.
Here, the crowning process on the outer peripheral surface of the single row needle roller 42 (single row roller) includes the outer ring raceway surface 20b, the inner ring raceway surface 30b, and the single row needle roller 42 (single row roller). For the purpose of preventing stress concentration occurring at both ends of the contact portion, by giving both ends of the bus bar of the single-row needle rollers 42 (single-row rollers) a slight curvature toward the axial center direction, This is a process that constitutes a so-called escape part.
The crowning process may be such that both ends of the single-row needle rollers 42 (single-row rollers) are formed in a spherical shape with a single radius of curvature. can do.
Between the crowning portions 42a at both ends of the single-row needle rollers 42 (single-row rollers), a cylindrical portion, that is, a linear portion 42b formed substantially in parallel with the axial center is provided. ing. Of the axial roller lengths of the single-row needle rollers 42 (single-row rollers), the axial length ratio occupied by the linear portion 42b can be set as appropriate. This crowning portion 42a can suppress stress concentration at the contact portion between the outer ring raceway surface 20b and the inner ring raceway surface 30b and the single row needle rollers 42 (single row rollers), that is, edge load. This is advantageous in preventing uneven wear.

The double-row needle rollers 44 (double-row rollers) are constituted by a plurality of rollers having a shorter length in the axial direction than the single-row needle rollers 42 (single-row rollers). The double-row needle rollers 44 (double-row rollers) also have crowned portions 44a that are crowned at both ends, similarly to the single-row needle rollers 42 (single-row rollers). In the first embodiment, the double-row needle rollers 44 (double-row rollers) are composed of two rollers that are approximately half the length of the single-row needle rollers 42 (single-row rollers). However, the double-row needle rollers 44 (double-row rollers) are not limited to two configurations, and may have three or more configurations.
Here, the straight portions 44b of the two double row needle rollers 44 (double row rollers) are both in contact with the straight portions 42b of the single row needle rollers 42 (single row rollers).
As shown in FIG. 4, since the double row needle rollers 44 (double row rollers) have crowning portions 44a at both ends, the double row needle rollers 44 (double row rollers) are axially arranged. Are adjacent to each other, the crowning portions 44a are adjacent to each other. Thereby, the site | part which does not contact the linear part 44b of the double row needle roller 44 (double row roller) is comprised in the axial center part in the linear part 42b of the single row needle roller 42 (single row roller). The That is, the straight portion 44b of the double-row needle roller 44 (double-row roller) is in partial contact with the straight portion 42b of the single-row needle roller 42 (single-row roller).

The rolling bearing device for a cam follower according to the first embodiment is configured as described above.
According to the rolling bearing device for a cam follower having such a configuration, the outer peripheral surface of the single-row needle roller 42 (single-row roller) is between the crowning portion 42a having both ends crowned and the crowning portion 42a. And a linear portion 42b that is formed and has an outer peripheral surface formed substantially parallel to the axis.
Similarly, the outer peripheral surface of the double-row needle rollers 44 (double-row rollers) is formed between the crowning portion 44a having both ends crowned and the crowning portion 44a, and the outer peripheral surface is substantially parallel to the axis. And a linear portion 44b formed.
The rollers are arranged adjacent to a single row of needle rollers 42 (single row rollers) and a single row of needle rollers 42 (single row rollers) formed to have substantially the same length as the width of the roller 20 in the axial direction. Thus, a combination of double row needle rollers 44 (double row rollers) in which a plurality of rollers having a shorter length than the single row needle rollers 42 (single row rollers) is formed in the axial direction is combined. . Accordingly, the straight portions 44b of the double row needle rollers 44 (double row rollers) are in partial contact with the straight portions 42b of the single row needle rollers 42 (single row rollers). The contacted portion is reduced, and the frictional resistance between the rollers can be suppressed. Therefore, it is possible to reduce the torque of the entire rolling bearing.
Further, when viewed from the strength side of the rolling bearing, the single row needle rollers 42 (single row rollers) having a long straight portion 42b are more effective. This rolling bearing device for a cam follower has a configuration in which double row needle rollers 44 (double row rollers) and single row needle rollers 42 (single row rollers) are combined in consideration of durability. Therefore, the frictional resistance between the rollers can be suppressed without impairing the durability of the rolling bearing as compared with the configuration of only the double row needle roller 44 (double row roller) bearing.

  The roller arrangement between the outer ring raceway surface 20b and the inner ring raceway surface 30b is such that single row needle rollers 42 (single row rollers) and double row needle rollers 44 (double row rollers) are alternately arranged. It is the composition which is. That is, the function of suppressing the frictional resistance between the rollers is effectively exhibited without impairing the durability of the rolling bearing.

  Next, a rolling bearing device for a cam follower according to Embodiment 2 of the present invention will be described with reference to FIGS. In addition, the same code | symbol may be attached | subjected to the same component as the said Example 1, and description may be abbreviate | omitted. As shown in FIGS. 5 and 6, in the second embodiment, in addition to the configuration of the first embodiment, there is a double row between the double row needle rollers 44 (double row rollers) in the axial direction. A ball 50 having the same diameter as that of the needle roller 44 (double row roller) is arranged and configured.

  Other configurations are the same as those in the first embodiment. As described above, the rolling bearing device for the cam follower according to the second embodiment performs the same function as that of the first embodiment, and can obtain the same actions and effects. Further, since the linear contact portion 42b of the single-row needle roller 42 (single-row roller) and the ball 50 are in point contact with each other, the single-row needle roller 42 (single-row roller) and the double-row needle are aligned. The frictional resistance between the tapered rollers 44 (double row rollers) can be further suppressed.

As mentioned above, although embodiment of this invention was described, the rolling bearing apparatus for cam followers of this invention is not limited to this embodiment, It can implement with other various forms.
For example, the rolling bearing device for the cam follower in the first embodiment described above has a configuration in which single row needle rollers 42 (single row rollers) and double row needle rollers 44 (double row rollers) are alternately arranged. Illustrated. However, the present invention is not limited to this, and the rolling bearing device for a cam follower according to the present invention includes a single row roller in which the roller arrangement is formed to have substantially the same length as the width in the axial direction of the roller, and a single row roller. The configuration in which a plurality of rollers having a length shorter than that of a single row roller is combined with a double row roller that is configured in the axial direction is sufficient, and a configuration in which a double row roller is combined adjacent to the single row roller is Otherwise, the configuration may be a single row roller, or the double row rollers may be adjacent to each other.

Further, the rolling bearing device for the cam follower in Example 2 has the same diameter as the double row needle rollers 44 (double row rollers) between the double row needle rollers 44 (double row rollers) in the axial direction. The ball 50 of diameter illustrated about arrangement | positioning structure. However, the present invention is not limited to this, and the rolling bearing device for a cam follower in the present invention may be one in which the ball 50 is not configured.
Moreover, it is the structure which combined the structure of the single row roller, the structure of the double row roller shown in Example 1, and the structure by which the ball | bowl 50 is arrange | positioned between the double row rollers shown in Example 2. Also good.

10 Rocker arm (Rolling bearing device for cam follower)
12 Body 14 Opposing wall 14a Support hole 16 Opposing wall 16a Support hole 18 Connecting wall 19 Connecting wall 20 Roller 20a Shaft insertion hole 20b Outer ring raceway surface 30 Shaft body 30a Both ends 30b Inner ring raceway surface 42 Single row needle rollers (single row) )
42a Crowning portion 42b Straight portion 44 Double row needle rollers (double row rollers)
44a Crowning portion 44b Linear portion 50 Ball 60 Cam 62 Rush adjuster 64 Valve stem

Claims (3)

A cylindrically formed roller has an inner peripheral surface as an outer ring raceway surface, and an outer peripheral surface of a shaft that is inserted into the roller is an inner ring raceway surface. A plurality of rollers are provided between the outer ring raceway surface and the inner ring raceway surface. In a rolling bearing device for a cam follower, the roller is configured to be freely rollable adjacent to the roller, and the roller is configured to be rotatable about an axial center by a cam being brought into rolling contact with the outer peripheral surface of the roller.
The outer peripheral surface of the roller includes a crowning portion that is crowned at both ends, and a linear portion that is formed between the crowning portions and the outer peripheral surface is formed substantially parallel to the axis.
The arrangement of the rollers is a single row roller formed to have substantially the same length as the width in the axial direction of the roller, and a double row roller in which a plurality of rollers having a shorter length than the single row roller are configured in the axial direction. A rolling bearing device for a cam follower characterized by comprising a combination of the above. A rolling bearing device for a cam follower according to claim 1,
A roller bearing device for a cam follower characterized in that the roller arrangement between the outer ring raceway surface and the inner ring raceway surface is such that the single row rollers and double row rollers are alternately arranged. A rolling bearing device for a cam follower according to claim 1 or 2,
A rolling bearing device for a cam follower, wherein balls having the same diameter as the diameter of the double row rollers are arranged between the double row rollers in the axial direction.

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