JP2001208165A - Cam follower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the durability of a cam follower with a floating ring by improving the lubricity. SOLUTION: In this cam follower 6 provided with a roller 9 rotatably mounted on a spindle 8 bridged over two opposite supports 7, 7, through a floating ring 10, an oil path 12 is formed on the supports 7 and the spindle 8, a through hole 13 is radially formed at an axial center of the floating ring 10, and further a hollow part 15 is formed around an outside opening of the through hole 13 of the floating ring 10, for supplying the lubricant to a sliding part of at least the roller 9 and the floating ring 10. This hollow part 15 ensures a lubricant storage space with respect to an inner peripheral surface of the roller 9, and an outside opening edge of the through hole 13 can be prevented from being directly kept into contact with the inner peripheral surface of the roller 9. Whereby the lubricant hardly flows to the external, and an oil film can be prevented from being scraped off by the outside opening edge of the through hole 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cam follower used for a valve operating mechanism of an engine, and more particularly to an improvement in a rotation support portion of a roller with respect to a support shaft.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a conventional cam follower. As shown in FIGS. 2 and 3, the cam follower 6 in the illustrated example is attached to a lash adjuster at the lower end of a push rod in an OHV type engine or a roller support member such as a rocker arm in an OHC type engine. The vehicle includes a support 7, a support shaft 8, rollers 9, and a floating wheel 10 as a slide bearing.

[0003] In an opposing space between the support shaft 8 and the roller 9, an oil passage 11 provided on the support 7, an oil passage 12 provided on the support shaft 8, and several places around the floating wheel 10 are provided. Lubricating oil is supplied through the through hole 13 provided along the radial direction.

The outer diameter side opening of the through hole 13 is enlarged in a mortar shape, but the inner diameter side opening of the through hole 13 is connected to the oil passage 12 of the support shaft 8 at any phase position. For this reason, the floating wheel 10 is opened in an annular groove 14 continuously formed on the entire inner peripheral surface of the floating wheel 10.

[0005]

In the conventional cam follower 6 described above, the lubricating oil supplied between the support shaft 8 or the roller 9 and the floating wheel 10 easily flows out to both sides in the axial direction. Since the outer diameter side opening edge of the through hole 13 provided in the floating wheel 10 becomes a form in which the oil film formed on the inner peripheral surface of the roller 9 is scraped, there is a possibility that a shortage of lubricating oil may occur.

In view of such circumstances, it is a primary object of the present invention to improve lubrication and improve durability in a cam follower having a floating wheel.

[0007]

SUMMARY OF THE INVENTION A first cam follower of the present invention is provided with two opposing supports, a support shaft mounted on the support in a bridging manner, and a required space rotatable with respect to the support shaft. A roller which is fitted to the cam and is fitted to the cam, and a floating wheel as a slide bearing interposed in an annular space between the roller and the support shaft, wherein the annular space is provided on the support and the support shaft. An oil passage for supplying lubricating oil is provided, and a radially extending through hole for guiding lubricating oil is provided between the roller and the floating wheel at an axial middle of the floating wheel,
A shallow dent is provided in a region surrounding the outer diameter side opening end of the through hole on the outer peripheral surface of the floating wheel.

[0008] A second cam follower according to the present invention is characterized in that, in the first configuration, the depression is formed in an annular shape over the entire circumference of the floating wheel.

The third cam follower of the present invention is characterized in that, in the second configuration, the recess is set to be gradually shallower toward the outer end side in the axial direction from the through hole.

[0010] In such a configuration, the lubricating oil guided to the through hole via the oil passage in the support shaft is supplied to the sliding portion between the roller and the floating wheel, and the lubricating oil is supplied to the depression on the outer peripheral surface of the floating wheel. It is stored. Therefore, the lubricating oil stored in the dent is less likely to flow out to both sides in the axial direction, and the lubricating oil stored in the dent is replenished to necessary parts in a timely manner. It becomes difficult. In addition, since the outer peripheral edge of the through hole does not directly contact the inner peripheral surface of the roller due to the depression, the oil film formed on the inner peripheral surface of the roller is not scraped off.

In particular, in the second configuration, since the recess is formed as an annular groove continuous in the circumferential direction, a sufficient amount of lubricating oil is held in the recess, and the sliding portion between the roller and the floating wheel is formed. An oil film can be formed without interruption over the entire circumference. Further, since the roller and the floating wheel come into sliding contact with a large span in the axial direction on both sides in the axial direction outside the recess, the roller is unlikely to be inclined.

Further, in the third configuration, since the wedge-shaped space is formed between the roller and the roller by making the both sides in the axial direction of the depression shallow, when the roller is displaced in the axial direction, the lubrication in the depression is reduced. The viscosity of the oil acts as a resistance to the displacement of the roller, thereby suppressing the rattling of the roller in the axial direction.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described based on embodiments shown in the drawings.

FIG. 1 is a longitudinal sectional view of a cam follower according to one embodiment of the present invention. Here, an example in which the cam follower of the present invention is applied to the valve mechanism of the engine shown in FIGS. 2 and 3 is described. FIG. 2 is a schematic configuration diagram of a valve mechanism of an OHV engine, and FIG. 3 is a schematic configuration diagram of a valve mechanism of an OHC engine.

In the example shown in FIG. 2, the push rod 2 is moved up and down by the cam 1a of the cam shaft 1 to swing the rocker arm 3 interlocking with the upper end thereof. The cam follower 6 is provided below the lash adjuster 5 provided at the lower end of the rocker arm 3.
Is provided.

In the example shown in FIG. 3, the rocker arm 3 is directly swung by the cam 1a of the cam shaft 1, and the swing of the rocker arm 3 causes the valve shaft 4a to open and close vertically. A cam follower 6 is provided on the rocker arm 3.

As shown in FIG. 1, each of these cam followers 6 has arms 7 and 7 as support members facing each other in parallel with each other, and a support shaft attached between these arms 7 and 7 in a bridging manner. A roller 9 is externally fitted to the roller 8 through a required space, and a floating wheel 10 as a slide bearing is provided in this annular space in a state where it can rotate relative to both the support shaft 8 and the roller 9. Is interposed.

The one arm 7 and the support shaft 8 are provided with oil passages 11 and 12 for supplying lubricating oil from outside. In addition, through-holes 13 are provided along the radial direction at several places on the center of the floating wheel 10 in the axial direction, which are evenly distributed around the circumference.
The inner end of the through hole 13 is connected to the oil passage 12 of the support shaft 8.

Although the outer diameter side opening of the through hole 13 is enlarged in a mortar shape, the inner diameter side opening of the through hole 13 is formed in an annular shape formed continuously around the entire inner peripheral surface of the floating wheel 10. It is open in the groove 14.

The lubricating oil supplied from outside via the oil passages 11 and 12 is guided between the support shaft 8 and the floating wheel 10, and the roller 9 and the floating wheel 10 via the through hole 13. Is also guided to the sliding portion of the.

An annular recess 15 extending in the circumferential direction is formed at a central portion in the axial direction on the outer peripheral surface of the floating wheel 10, and an outer diameter side of the through hole 13 is formed in a region where the recess 15 exists. An opening is located.

Here, the recess 15 is a concave curved surface having a large curvature so as to gradually become shallower from the center in the axial direction toward both sides, and two flat portions on both sides in the axial direction of the floating wheel 10 are formed as follows. It is a sliding portion for the roller 9.

If such a configuration is adopted, the support shaft 8
The lubricating oil guided to the through-hole 13 of the floating wheel 10 from the oil passage 12 in the inside is supplied to a sliding portion between the roller 9 and the floating wheel 10, and a depression formed on the outer peripheral surface of the floating wheel 10. 1
5 will be stored. Therefore, even if the lubricating oil supplied to the sliding portion between the roller 9 and the floating wheel 10 flows out to both sides in the axial direction, the lubricating oil stored in the depression 15 is gradually and gradually supplied to the sliding portion. That is, an oil film can always be formed on the sliding portion. Moreover, since the outer diameter side opening of the through-hole 13 is not in contact with the inner peripheral surface of the roller 9 due to the depression 15, the oil film formed on the inner peripheral surface of the roller 9 is not scraped off.

The depression 15 of the floating wheel 10 is
Since a wedge-shaped space narrowed toward both sides in the axial direction is formed between the roller 9 and the inner peripheral surface of the roller 9,
When the roller 9 is to be displaced in the axial direction, the viscosity of the lubricating oil stored in the wedge-shaped space described above acts as a resistance to the axial displacement of the roller 9 and suppresses the axial direction of the roller 9.

Further, since the roller 9 and the floating wheel 10 come into sliding contact with a large span in the axial direction on both sides in the axial direction outside the recess 15, the roller 9 is hardly inclined.

It should be noted that the present invention is not limited to the above-described embodiment, and various applications and modifications are conceivable.

(1) The recess 15 may be a rectangular recess instead of a concave curved surface.

(2) The recesses 15 are not formed as annular grooves continuous in the circumferential direction, but are formed independently of each other only in regions surrounding the through holes 13 provided at several places on the circumference. There may be.

[0029]

According to the cam followers of the first to third aspects of the present invention, the depression provided on the outer peripheral surface of the floating wheel improves the lubricating oil holding performance particularly at the sliding portion between the roller and the floating wheel. Even if the lubricating oil flows out to both sides in the axial direction of the moving part, the lubricating oil in the dent may be continuously supplied to the sliding part. Since the oil film formed on the inner peripheral surface of the roller is not scraped off by directly contacting the inner peripheral surface, it is possible to maintain good lubrication of the sliding portion between the roller and the floating wheel for a long period of time. Can greatly contribute to the improvement of durability.

In particular, according to the second aspect of the present invention, since the depression is an annular groove that is continuous in the circumferential direction, uniform and suitable lubrication can be performed over the entire circumference of the sliding portion, and the durability is improved. This is advantageous.

According to the third aspect of the present invention, the wedge-shaped space is formed between the roller and the roller by making the both sides of the recess shallower in the axial direction. The roller acts as a resistance for preventing the play in the axial direction, which contributes to stabilization of the attitude of the roller, which is advantageous for always properly maintaining the contact state between the roller and the cam.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a cam follower according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of use of the cam follower of FIG. 1;

FIG. 3 is an explanatory view showing another example of use of the cam follower in FIG. 1;

FIG. 4 is a longitudinal sectional view showing an example of a conventional cam follower.

[Description of Signs] 6 Cam follower 7 Support 8 Support shaft 9 Roller 10 Floating wheel 12 Oil passage 13 Through hole 15 Depression

Claims (3)

[Claims] An opposed support, a support shaft mounted on the support in a cross-linking manner, a required space rotatably provided with respect to the support shaft, externally fitted and abutted on a cam. A roller, and a floating wheel as a slide bearing interposed in an annular space between the roller and the support shaft, wherein an oil path for supplying lubricating oil to the annular space is provided in the support and the support shaft. A radially extending through-hole for guiding lubricating oil between the roller and the floating wheel is provided at an axially intermediate portion of the floating wheel, and an outer diameter of the through-hole on an outer peripheral surface of the floating wheel. A cam follower, wherein a shallow depression is provided in a region surrounding the side opening end. 2. The cam follower according to claim 1, wherein the recess is formed in an annular shape over the entire circumference of the floating wheel. 3. The cam follower according to claim 2, wherein the recess is set to be gradually shallower from the through hole toward the outer end in the axial direction.