JPH0558802U - Valve drive for internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to simplify the structure of a valve train of an internal combustion engine that includes a roller that rolls on a cam. [Structure] The valve lifter 1 has a recess 13 recessed in an arc shape in section.
And the roller 2 rolling on the cam 5 is rotatably accommodated in the recess 13.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to an improvement in a valve train of an internal combustion engine.

[0002]

[Prior Art]

 As a conventional valve operating system for an internal combustion engine, for example, there is one shown in FIGS. 5 and 6 (see Japanese Patent Publication No. 52-27290).

To explain this, the valve lifter 1 reciprocates following the rotation of a cam (not shown) to open and close an intake / exhaust valve via a push rod or rocker arm (not shown).

A roller 2 rollingly contacted with the cam is rotatably coupled to the valve lifter 1 via a pin 3 to reduce friction on the cam.

[0005]

[Problems to be solved by the device]

 However, in such a conventional device, there is a problem in that the roller 2 is coupled to the valve lifter 1 via the pin 3 so that the number of parts is increased and the cost is increased.

The present invention aims to solve the above problems.

[0007]

[Means for Solving the Problems]

 According to the present invention, in a valve operating system for an internal combustion engine including a valve lifter that reciprocates via a roller rolling on a cam, a concave portion having an arcuate cross section is formed in the valve lifter, and the roller can be rotated in the concave portion. Put in.

[0008]

[Function] With the rotation of the cam, the valve lifter reciprocates following the cam while rotating the roller in the concave portion to open / close the intake / exhaust valve. At this time, the rolling contact of the roller with the cam can significantly reduce the friction generated between the cam and the valve lifter.

By interposing the roller between the concave portion of the valve lifter and the cam, the pin for rotatably supporting the roller with respect to the valve lifter as in the conventional device can be eliminated and the number of parts can be reduced.

[0010]

【Example】

 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

As shown in FIG. 1, the tubular valve lifter 1 reciprocates in the vertical direction by following a cam 5 (not shown), and the push rod 6 reciprocates in contact with the pan 11 of the valve lifter 1 and is not shown. The intake / exhaust valves are opened / closed via a rocker arm provided on the cylinder head.

The valve lifter 1 is provided at its lower end with a roller 2 rollingly contacting the cam 5, and follows the cam 5 via the roller 2.

As shown in FIGS. 2 and 3, the roller 2 is formed in the shape of a right circular cylinder, and has an outer peripheral surface 21 rolling on the cam 5 and an end surface 22 orthogonal to the rotation center axis. is doing. The outer peripheral surface 21 is hardened to have sufficient wear resistance.

The lower surface 12 of the valve lifter 1 is formed with a recess 13 for rotatably housing the roller 2.

The recess 13 of the valve lifter 1 has a semi-circular cross section, and the radial side bearing surface 14 for slidingly contacting the outer peripheral surface 21 of the roller 2 and the thrust side bearing surface 15 for slidingly contacting both end surfaces 22 of the roller 2 are provided. Formed by.

The valve lifter 1 is manufactured by, for example, a method of molding powder metal and then sintering it, or a method of casting it using a precise mold.

A through hole 16 that connects the pan portion 11 of the valve lifter 1 and the recess 13 is formed. Oil is supplied into the valve lifter 1 from a lubrication passage (not shown), the oil lubricates the sliding contact portion between the tray portion 11 and the push rod 6, and further passes through the through hole 16 to slide between the recess 13 and the roller 2. It is designed to lubricate the contact area.

Next, the operation will be described.

With the rotation of the cam 5, the valve lifter 1 reciprocates while following the cam 5 while rotating the roller 2 in the recess 13, and through the push rod 6 and a rocker arm provided on a cylinder head (not shown). To open and close the intake and exhaust valves. At this time, the roller 2 rollingly contacts the cam 5, so that the friction generated between the cam 5 and the valve lifter 1 can be significantly reduced.

Since the roller 2 is regulated in downward displacement by rollingly contacting the cam 5, it does not fall out of the recess 13.

As described above, by interposing the roller 2 between the concave portion 13 of the valve lifter 1 and the cam 5, the pin 3 for rotatably supporting the roller 2 with respect to the valve lifter 1 as in the conventional device is provided. It can be abolished and the number of parts can be reduced.

Next, in another embodiment shown in FIG. 4, the valve lifter 1 is provided with a cap 7 for preventing the roller 2 from coming off, thereby improving the assemblability.

The cap 7 has a tubular portion 25 fitted to the outer peripheral surface 19 of the valve lifter 1 and an opening portion 26 facing the outer peripheral surface 21 of the roller 2 with a predetermined clearance. The opening 26 has a rectangular shape having the maximum opening width L, and the maximum opening width L is formed smaller than the outer diameter D of the roller 2 so that the falling of the roller 2 is locked during assembly.

[0024]

[Effect of the device]

 As described above, according to the present invention, the valve lifter is provided with the recessed portion having an arcuate cross section, and the roller rolling on the cam is rotatably accommodated in the recessed portion, so that the roller is rotatably supported by the valve lifter. The cost will be reduced by eliminating pins and reducing the number of parts.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is a plan view of the same.

FIG. 4 is a sectional view showing another embodiment.

FIG. 5 is a cross-sectional view showing a conventional example.

FIG. 6 is a sectional view of the same main part.

[Explanation of symbols]

 1 Valve Lifter 2 Roller 5 Cam 6 Push Rod 13 Recess

Claims (1)

[Scope of utility model registration request] 1. A valve operating system for an internal combustion engine, comprising a valve lifter which reciprocates via a roller rolling on a cam.
A valve operating device for an internal combustion engine, wherein a recessed portion having an arcuate cross section is formed in the valve lifter, and the roller is rotatably accommodated in the recessed portion.