JPH0723525Y2 - Valve rotation device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a valve rotating device that is mounted on an intake valve and an exhaust valve of an internal combustion engine to rotate the valve and prevent uneven wear thereof. .

[Conventional technology]

Since the intake valve and exhaust valve of an internal combustion engine frequently repeat opening and closing operations during the period of operation, there is a risk of uneven wear with the valve seat of the cylinder head due to manufacturing errors and assembly errors of these valves. There is. If such uneven wear is left, it becomes difficult to completely seal the inside of the cylinder. Therefore, it is necessary to rotate the intake and exhaust valves to prevent uneven wear.

As a method of rotating this valve, there is known a method of rotating the valve around its axis in association with the operation of a rocker arm that abuts against the upper end of the valve shaft of the valve and opens it. (See Japanese Patent Publication No. 57-44803 and Japanese Patent Publication No. 58-55323). In the valve rotating device described in Japanese Patent Publication No. 57-44803, the surface of the rocker arm that comes into contact with the valve is spherical, and the point of action of this rocker arm on the valve is the axis of the valve from the axis of the rocker shaft. The valve is arranged so as to be deviated by a predetermined amount in the axial direction, and the valve is rotated around its axis by the operation of a rocker arm.

[Problems to be solved by the invention]

However, in the valve rotation device configured as described above,
If the internal combustion engine does not reach high speed, it will be difficult to rotate the valve.
Further, when the valve is seated on the valve seat of the cylinder portion, the valve is seated while rotating, so that there is a problem that the valve and the seat are severely worn.

The present invention has been made in view of the above problems, and it is possible to rotate the valve stably even when the internal combustion engine is running at low speed. Further, when the valve is seated, the valve is prevented from rotating and excessive wear occurs. It is an object of the present invention to provide a valve rotation device which can prevent the above and has a simple structure.

[Means for solving problems]

In order to solve the above problems, the present invention has the following configuration. That is, the present invention is directed to an intake / exhaust valve that opens and closes an intake / exhaust port that opens to a combustion chamber, a cam that rotates in synchronization with an internal combustion engine, and a substantially spherical shape that is supported by a rocker shaft and abuts on the intake / exhaust valve. A rocker having a surface and provided with a point of action on the intake / exhaust valve deviated by a predetermined amount from the axis of the intake / exhaust valve in the axial direction of the rocker shaft, and transmitting the operation of the cam to the intake / exhaust valve. An arm, a spring for constantly urging the intake / exhaust valve in a closing direction, a retainer body fixed to the intake / exhaust valve, a plurality of needle rollers provided between the retainer body and the spring, and the retainer. A plurality of slits provided between the main body and the spring and having a width smaller than the diameter of the needle roller are provided radially with respect to the axis of the intake / exhaust valve, and from the slits, Part of the idler roller is protruded toward the spring, and the needle roller is directly contacted with the end surface of the spring so as not to fall off to the outside to hold the needle roller and further than the outer peripheral portion of the retainer body. A technical means called a valve rotating device of an internal combustion engine, characterized in that an outer peripheral portion protruding toward the outer peripheral side is formed, and a case for introducing lubricating oil into the needle roller is provided.

[Action]

According to the present invention having the above-mentioned structure, the intake / exhaust valve which is normally urged to the closed position is pushed down by the operation of the rocker arc to open the intake / exhaust port. At this time, the rocker arm has a substantially spherical contact surface. Comes into point contact with the end face of the intake / exhaust valve. Here, since the action points of the rocker arm and the intake / exhaust valve are biased by a predetermined amount, a force acts to rotate the intake / exhaust valve around the axis. The magnitude and direction of this acting force differ depending on the rocking position (displacement angle) of the rocker arm and the state of the intake / exhaust valve, that is, whether the intake / exhaust valve is in the open stroke or closed stroke. At the beginning of the stroke, a torque exceeding the static torque of the bearing acts on the intake / exhaust valve by the rocker arm to rotate the intake / exhaust valve in a fixed direction. In addition, even if the internal combustion engine is rotated at high speed and the spring surging occurs and the spring violently vibrates,
Due to the action of the needle bearing of the friction reducing mechanism, the torsional vibration of the spring is not transmitted to the intake and exhaust valves and does not rotate when the intake and exhaust valves are seated. Further, the needle roller of the needle bearing is held in the case by a slit having a width smaller than the diameter of the needle roller provided in the case, so that the end surface of the spring is prevented by the portion protruding from the slit without falling out of the case. It directly abuts and rolls on the end face of the spring. As described above, in the present invention, the needle roller and the case that holds the needle roller form a needle bearing, and the needle bearing forms a friction reduction mechanism between the intake / exhaust valve and the spring. Furthermore, since the outer peripheral portion of the needle bearing case projects further outward than the outer peripheral portion of the retainer body, the lubricating oil that falls from the rocker arm or retainer body protrudes further outward than the outer peripheral portion of the retainer body. It is received by the outer peripheral portion of the case and is introduced into the needle bearing through the slit.

〔Example〕

Next, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a vertical sectional view showing the outline of this embodiment, and FIG. 2 is an enlarged sectional view of part A of FIG.

First, the configuration of this embodiment will be described with reference to FIG. In FIG. 1, the rocker arm 1 swings around the rocker shaft 2 and drives the intake / exhaust valve 3 in the vertical direction in the figure by the action of a cam (not shown) that rotates in synchronization with the rotation of the engine. The contact surface 101 of the rocker arm 1 that comes into contact with the intake / exhaust valve 3 has a spherical shape. The contact surface 101 is displaced from the central axis 302 of the intake / exhaust valve 3 by a predetermined amount δ in the axial direction of the rocker shaft 2. The contact point 303 is in contact with the end surface 301 of the intake / exhaust valve 3. Here, the lubricating oil flows between the contact surface 101 of the rocker arm 1 and the end surface 301 of the intake / exhaust valve 3.

The rocker shaft 2 is fixed in the internal combustion engine, and supports the rocker arm 1 rotatably in a direction around the rocker shaft 2. The intake / exhaust valve 3 is supported by the valve guide 5 so as to be rotatable about the central axis 302 of the intake / exhaust valve 3 and slidable in the direction of the central axis 302. When the rocker arm 1 is not receiving the force, the intake / exhaust valve 3 is biased upward by the spring 7 through the retainer 6 in FIG. Seal tightly. The retainer 6 is the retainer body 60.
1 and a needle bearing 602, the retainer body 601 is fixed to the intake / exhaust valve 3 by the cotter 4,
The force of the spring 7 is transmitted to the intake / exhaust valve 3 via the needle bearing 602. A portion of the retainer body 601 facing the needle bearing 602 is provided with a raceway surface 601a that is a smooth flat surface and a cylindrical surface 601b that has a cylindrical shape.
The needle bearing 602 is a ring-shaped thrust bearing, and the inner diameter portion is supported by the cylindrical surface 601b of the retainer body 601. The needle bearing 602 is the retainer body 601.
It is located between the spring 7 and the spring 7, and transmits the force of the spring 7 to the intake / exhaust valve 3 via the retainer body 601 and the cotter 4, while reducing the friction between the intake / exhaust valve 3 and the spring 7 in the rotation direction. Further, the needle bearing 602 is composed of a plurality of needle rollers 632, an upper case 612 and a lower case 622. As shown in FIG.
The upper case 612 is held in a case formed by fitting the lower case 622. Top case 612
The upper surface slit 612a and the lower surface case 622 are provided with an upper surface slit 612a and a lower surface slit 622a, respectively.
And the lower slit 622a is a ring-shaped needle bearing
It is provided along the central direction of 602. The needle roller 632 has the upper surface slit 612a and the lower surface slit 622a.
It is in contact with the raceway surface 601a of the retainer body 601 and the upper end surface 7a of the spring 7 via the.

Furthermore, the outer diameter 602c of the lower case 622 is equal to the retainer body 601.
It is larger than the outer diameter 601c of the outer peripheral portion 601d. That is, when the needle bearing 602 is interposed between the retainer body 601 and the spring 7, the outer peripheral portions of the upper case 612 and the lower case 622 are the outer peripheral portions 601d of the retainer body 601.
It is designed to project to the outer peripheral side. Further, when the upper surface case 612 is fitted in the lower surface case 622, the tip portion 622c of the lower surface case 622 projects above the upper surface 612b of the upper surface case 612.

Next, the operation of this embodiment will be described with reference to FIG. First
In the figure, in this embodiment, the rocker arm 1 is swung by a cam (not shown), and the intake / exhaust valve 3 that is normally biased to the closed position is a substantially spherical contact surface 101 of the rocker arm 1.
Is brought into contact with the end surface 301 of the intake / exhaust valve 3 to be displaced downward in FIG. At that time, since the action point 303 between the rocker arm 1 and the intake / exhaust valve 3 is displaced from the central axis 302 of the intake / exhaust valve 3 by a predetermined amount δ in the axial direction of the rocker shaft 2, The force that tries to rotate around the axis works. This acting force varies in magnitude and direction depending on the rocking position (displacement angle) of the rocker arm 1 and the state of the intake / exhaust valve 3, that is, whether the intake / exhaust valve 3 is in the open stroke or the closed stroke. A torque exceeding the static torque of the needle bearing 602 acts on the intake / exhaust valve 3 by the rocker arm 1 in the initial stage of the valve closing stroke, and the intake / exhaust valve 3 rotates in a fixed direction. By this rotation, it is possible to prevent local overheating of the intake / exhaust valve 3 and the valve seat 8, adhesion of foreign matter, and uneven wear. Further, even if the internal combustion engine is rotated at high speed and surging of the spring 7 occurs, and the spring 7 violently vibrates torsionally, the torsional vibration of the spring 7 is not transmitted to the intake / exhaust valve 3 by the action of the needle bearing 602. The intake / exhaust valve 3 does not rotate when the valve seat 8 is seated. Therefore, it is possible to prevent abnormal wear due to rotation of the intake / exhaust valve 3 when the valve seat 8 of the intake / exhaust valve 3 is seated.

Further, the upper case 612 that constitutes the needle bearing 602
And the outer circumference of the lower case 622 is the outer circumference of the retainer body 601.
The lower end case 622 has a tip end portion 622c that protrudes above the upper surface 612b of the upper surface case 612. Therefore, the lubricating oil flowing between the contact surface 101 of the rocker arm 1 and the end surface 301 of the intake / exhaust valve 3 is the rocker arm 1 or the retainer body 601.
Along the outer periphery of the retainer body 601.
It is received by the outer peripheral portions of the upper surface case 612 and the lower surface case 622 that project to the outer peripheral side from 01d. Here, since the tip portion 622c of the lower case 622 projects above the upper surface 612b of the upper case 612, the lubricating oil does not spill from the case, and the bearing 602 passes through the upper slit 612a.
Will be introduced in. As a result, it is possible to prevent performance deterioration and wear of the needle bearing 602 due to lubrication oil breakage. In this embodiment, the needle bearing 602 is composed of the upper case 612 and the lower case 622.
Although the case 632 is held, the same effect can be obtained by using the case 642 integrally formed with the case as shown in FIG.

[Effect of device]

As described above, in the present invention, the points of action of the intake / exhaust valve and the rocker arm are deviated by a predetermined amount from the axis of the intake / exhaust valve,
A friction reducing mechanism is provided between the intake / exhaust valve and the spring to reduce friction between the intake / exhaust valve and the spring.
As a result, the intake / exhaust valve can be reliably rotated even at low engine speeds, and rotation of the intake / exhaust valve due to spring surging at high engine speed is prevented, so that the intake / exhaust valve does not rotate when seated. Excessive wear of the intake / exhaust valve and the valve seat can be prevented.

The needle bearing that constitutes the friction reducing mechanism is composed of a plurality of needle rollers and a case that holds the needle rollers inside, and the case is provided with a slit having a width smaller than the diameter of the needle rollers. As a result, the needle roller is held in the case so as not to fall out, and a part of the needle roller projects from the case to directly contact the spring. Therefore, the friction reducing mechanism can be configured with a simple structure without interposing a special member between the spring and the needle roller. Further, according to this invention, the outer peripheral portion of the case is configured to project more toward the outer peripheral side than the outer peripheral portion of the retainer body with which it abuts. By doing so, the lubricating oil flowing downward through the rocker arm or the retainer body is received by the case outer peripheral portion projecting to the outer peripheral side than the outer peripheral portion of the retainer main body, and is introduced into the needle bearing,
It is possible to prevent performance deterioration and wear due to lubrication of the needle bearing.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 relate to an embodiment of the present invention. FIG. 1 is a longitudinal sectional view showing the outline of the present embodiment, and FIG. 2 is an enlarged view of part A of FIG. FIG. FIG. 3 relates to another embodiment of the present invention and is an enlarged sectional view of a needle bearing of this embodiment. 1 …… rocker arm, 101 …… contact surface, 2 …… rocker shaft, 3 …… intake / exhaust valve, 6 …… retainer, 601 …… retainer body, 602 …… needle bearing, 612 …… upper case, 6
12a …… Top slit, 622 …… Bottom case, 622a …… Bottom slit, 632 …… Needle roller, 7 …… Spring.

Front page continuation (72) Hiromi Kato 14 Iwatani, Shimohakaku-cho, Nishio-shi, Aichi Prefecture Japan Auto Parts Research Institute, Inc. (72) Inventor Ken Tagami 1 Toyota-cho, Toyota City, Aichi Prefecture (72) Inventor Toru Kawase 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (56) Bibliography Sho 31-13702 (JP, Y1) West German Patent Publication 3304878 (DE, A)

Claims (1)

[Scope of utility model registration request] 1. An intake / exhaust valve that opens and closes an intake / exhaust port that opens to a combustion chamber, a cam that rotates in synchronization with an internal combustion engine, and a substantially spherical contact that is supported by a rocker shaft and contacts the intake / exhaust valve. A rocker having a surface and provided with a point of action on the intake / exhaust valve deviated by a predetermined amount from the axis of the intake / exhaust valve in the axial direction of the rocker shaft, and transmitting the operation of the cam to the intake / exhaust valve. An arm, a spring for constantly urging the intake / exhaust valve in a closing direction, a retainer body fixed to the intake / exhaust valve, a plurality of needle rollers provided between the retainer body and the spring, and the retainer. Provided between the main body and the spring,
A plurality of slits having a width smaller than the diameter of the needle roller are provided radially with respect to the axis of the intake / exhaust valve, and a part of the needle roller is projected from the slit to the spring side to form the needle roller. The needle roller is held by directly contacting the end surface of the spring so that it does not fall outside, and an outer peripheral portion is formed that protrudes further outward than the outer peripheral portion of the retainer body. A valve rotating device for an internal combustion engine, comprising: