JPH0596405U - Engine valve rotator - Google Patents

Abstract

(57) [Summary] [Object] To provide a highly reliable valve rotator for an engine that is capable of preventing uneven wear around intake and exhaust valves, is suitable for high-speed engine rotation. [Structure] A spring retainer 6 connected to a valve stem end 1b via a cotter 5 and a valve spring 7 for biasing the valve 1 in the closing direction via the spring retainer 6 are provided. Inner springs 7 arranged inside and outside with the same winding direction
b and the outer spring 7a, the inner spring 7b is adapted to move in accordance with the expansion and contraction of the spring retainer 6b.
Of the engine, one end of which is regulated in the winding direction to be fixed to the cylinder head 2 so that the other end can be freely rotated in the winding direction and is elastically contacted with the spring retainer 6. Valve rotator.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a valve rotator for an engine, in which the intake valve and the exhaust valve are rotated by a predetermined angle according to the operation of the engine to prevent uneven wear.

[0002]

[Prior Art]

 Generally, the intake and exhaust valves of an engine are urged in the closing direction by a valve spring so that the valve face is in close contact with the valve seat to close the intake and exhaust ports, and the cam and rocker arms open against the valve spring. The valve face is configured to open away from the valve seat and open the exhaust port when pushed in the direction. That is, the intake and exhaust valves open and close the intake and exhaust ports by repeating the reciprocating motion according to the operation of the engine. Therefore, when the intake / exhaust valve is worn, uneven wear is likely to occur around the shaft, resulting in uneven wear.

Here, if uneven wear occurs on the valve face of the intake and exhaust valves or the valve seat, the temperature distribution of that part becomes non-uniform during engine combustion, causing thermal strain, which causes burnout of the valve seat and valve. It may cause a loss of the umbrella part. Further, the engine output is also reduced due to the deterioration of the adhesion performance between the valve face and the valve seat, and unburned gases such as HC and CO are inadvertently leaked on the exhaust valve side. Furthermore, if the valve stem or valve stem guide is unevenly worn, it may cause galling or sticking, and smooth opening / closing operation of the valve cannot be expected.

Therefore, conventionally, various valve rotators have been proposed in which intake / exhaust valves are rotated around an axis in accordance with engine operation to prevent uneven wear around the intake / exhaust valves (actual exploitation). 59-79506, Japanese Utility Model Laid-Open No. 53-68817, Japanese Utility Model Laid-Open No. 54-10107).

FIG. 3 shows an example thereof. A ring groove d is formed on the lower surface of a spring retainer c connected to a stem end a of a valve via a cotter b, and a coil spring is formed in this ring groove d. e is attached in the form of a ring with both ends joined. A disc spring f is attached to the spring retainer c so as to be in contact with the lower surface of the coil spring e, and the disc spring f is elastically held upward by a valve spring h via a retainer g.

According to the conventional valve rotator configured as described above, the stem end a of the valve is pushed by the cam or the rocker arm as the engine operates, and the spring retainer c moves the disc spring f and the retainer g. The coil spring e is crushed in the thickness direction by elastic deformation and flattening of the disc spring f during opening of the valve that compresses the valve spring h via the coil spring e along the ring groove d. By falling in the longitudinal direction, the spring retainer c, which makes frictional contact with this, rotates in one direction by a very small amount. When the valve spring h elastically returns, when the valve is closed, the disc spring f also elastically returns and the coil spring e returns from the tilted state in the longitudinal direction. When the valve is closed again, the coil spring e moves in the longitudinal direction. The spring retainer c is tilted and slightly rotated in one direction, and thus the valve together with the spring retainer c is rotated in small amounts by one minute to rotate in one direction.

[0007]

[Problems to be solved by the device]

 By the way, the above-described conventional valve rotator requires the coil spring e, the disc spring f, the retainer g, etc. as additional components, and the inertial mass of the valve train increases due to the increase in the number of components, so the high speed rotation of the engine There is a problem that it is not suitable for conversion. Another problem is that the reliability of performance is low due to the large number of parts.

[0008] Therefore, it is an object of the present invention to provide a highly reliable valve rotator for an engine, which can prevent uneven wear around intake and exhaust valves, and is suitable for high-speed engine rotation. ..

[0009]

[Means for Solving the Problems]

 For this purpose, the valve rotator of the engine according to the present invention comprises a spring retainer connected to the valve stem end through a cotter, and a valve spring for biasing the valve in the closing direction through the spring retainer. The valve spring is composed of an inner spring and an outer spring which are arranged inside and outside with the same winding direction, and the inner spring rotates the spring spring by a predetermined amount according to its expansion and contraction. The means is that one end of the spring retainer is regulated to rotate in the winding direction and is fixed to the cylinder head, and the other end is elastically rotatable in the winding direction and elastically contacted with the spring retainer.

In addition to this, in the spring retainer of the spring retainer to which the other end of the inner spring elastically contacts, a ratchet whose other end is over the mountain when the inner spring is extended is provided with a ring. It is formed as a means.

[0011]

[Action]

 According to the valve rotator of the engine adopting such a means, when the valve that is compressed by the valve spring is opened when the engine is operated, the other end of the inner spring rotates a predetermined amount in one direction along its winding direction. The spring retainer that moves and makes elastic contact with it also rotates in the same direction. When the valve spring is elastically restored and extends, when the valve is closed, the other end of the inner spring rotates a predetermined amount in the opposite direction along the winding direction, and the spring retainer also rotates in the opposite direction. Since the frictional contact force between the other end of the inner spring and the spring retainer is greater when the inner spring is compressed than when it is expanded due to elastic return, the amount of rotation of the spring retainer is large in one direction. , The spring retainer becomes smaller in the opposite direction, and the spring retainer rotates in one direction by the difference, and thus the valve continues to rotate in one direction together with the spring retainer. Therefore, uneven wear around the valve is prevented.

From a structural point of view, since the inner spring is added and the mass of the additional parts does not increase much, the increase in the inertial mass of the valve train is smaller than in the past, and the engine can be rotated at high speed. Suitable. In addition, since the number of additional parts is small, there is little operation loss and high reliability can be obtained.

Further, according to the procedure in which the ring-shaped ratchet is added to the spring receiving portion of the spring retainer, the spring retainer surely rotates in one direction when the inner spring is compressed, so that higher reliability can be obtained. ..

[0014]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In FIG. 1 showing the first embodiment of the present invention, reference numeral 1 is an exhaust valve for opening and closing an exhaust port 3 formed in a cylinder head 2, and of a valve stem 1a slidably fitted in a stem guide 4. A spring retainer 6 is connected to the valve stem end 1b via a cotter 5. Then, the spring retainer 6 is biased by the valve spring 7, so that the valve head portion 1c comes into close contact with the valve seat 8 to close the exhaust port 3. Further, the rocker arm 9 in contact with the valve stem end 1b pushes the valve stem 1a against the valve spring 7, so that the valve head portion 1c is separated from the valve seat 8 and the exhaust port 3 is opened. There is.

Here, the valve spring 7 has an outer spring 7a having a large number of turns, one end of which is in free contact with the spring receiving portion 2a of the cylinder head 2 and the other end of which is in free contact with the spring receiving portion 6a of the spring retainer 6. And an inner spring 7b arranged inside the outer spring 7a and having a small number of turns. The inner spring 7b is fixed to the spring receiving portion 2a of the cylinder head 2 via the knock pin 10 so that one end of the inner spring 7b is restricted from rotating in the winding direction, and the other end is free. It is elastically contacted with the portion 6b and freely rotatable in the winding direction.

Next, the operation of the valve rotator of the first embodiment configured as described above will be described. As the rocker arm 9 repeatedly swings as the engine runs, the exhaust valve 1 pushes the valve stem 1a against the outer spring 7a and the inner spring 7b, causing the valve umbrella portion 1c to move away from the valve seat 8 and exhaust. When the port 3 is opened and the outer spring 7a and the inner spring 7b elastically return, the valve head portion 1c comes into close contact with the valve seat 8 and closes the exhaust port 3, thus continuing the opening and closing of the exhaust port 3 at a predetermined timing. .. During the opening / closing operation of the exhaust port 3 by the exhaust valve 1, the outer spring 7a and the inner spring 7b repeatedly expand and contract by compression and elastic return.

The inner spring 7b which repeatedly expands and contracts has one end regulated to rotate in the winding direction and the other end freely rotatable in the winding direction. Therefore, when compressed, the other end moves along the winding direction. It repeatedly rotates in one direction and then in the opposite direction along the winding direction at the time of elastic recovery. The spring retainer 6 in which the spring receiving portion 6b is in elastic contact with the other end of the inner spring 7b also repeats the rotation in one direction and the rotation in the opposite direction according to the frictional contact force.

Here, the frictional contact force between the other end of the inner spring 7b and the spring receiving portion 6b of the spring retainer 6 is greater when the inner spring 7b is compressed than when it is elastically restored. The amount of rotation of the spring retainer 6 increases in one direction and decreases in the opposite direction, and the spring retainer 6 rotates in one direction by the difference. Thus, the exhaust valve 1 in which the valve stem end 1b is connected to the spring retainer 6 via the cotter 5 rotates by a predetermined amount for each opening / closing operation and continues to rotate around the shaft.

Therefore, the contact surface between the valve umbrella portion 1c of the exhaust valve 1 and the valve seat 8, the sliding surface between the valve stem 1a and the stem guide 4, or the contact surface between the valve stem end 1b and the rocker arm 9 is uniform. Wear around the exhaust valve 1 is prevented. Further, by maintaining the adhesion performance between the valve head portion 1c and the valve seat 8 for a long period of time, it is possible to avoid a decrease in engine output and eliminate the inconvenience that unburned gas such as HC and CO leaks carelessly. To do. In addition, since the sticking and sticking of the valve stem 1a with respect to the stem guide 4 are also prevented, the exhaust valve 1 continues to open and close smoothly.

Further, since the exhaust valve 1 rotates about the axis, the temperature distribution of the valve umbrella portion 1c and the valve seat 8 is made uniform, so that the valve umbrella portion 1c is damaged and the valve seat 8 is burned out. To be prevented.

Here, looking at the valve rotator of the first embodiment structurally, it is a structure in which the inner spring 7b and the knock pin 10 are added to the structure around a general exhaust valve, and there is little increase in the mass of additional parts. Therefore, the increase in the inertial mass of the valve train is smaller than before, and it is suitable for high-speed engine rotation. Also, since the number of additional parts is small, there is little operation loss and high reliability is obtained.

FIG. 2 is an enlarged view showing the structure of the essential parts of the second embodiment of the present invention, and the parts not shown have the same construction as the first embodiment. Here, in the spring retainer 6, a ratchet 6c is formed in a ring shape on a spring receiving portion 6b which comes into contact with the other end of the inner spring 7b. The ratchet 6c engages with the other end of the ratchet 6c when it is rotated in one direction along the winding direction when the inner spring 7b is compressed, and the other end is rotated in the opposite direction when the inner spring 7b is extended. When doing, the orientation of the teeth is set so that the other end gets over the mountain.

The valve rotator according to the second embodiment basically has the same effect as the valve rotator according to the first embodiment, but the other end of the valve rotator is engaged with the ratchet 6c when the inner spring 7b is compressed. Since the spring retainer 6 is surely rotated in one direction, the exhaust valve 1 can be surely rotated about the axis by a predetermined amount, and higher reliability can be obtained as compared with the first embodiment. ..

The rotation speed of the exhaust valve 1 can be adjusted by appropriately selecting the wire diameter and the number of turns of the inner spring 7b in the first and second embodiments.

In the first and second embodiments, the example in which the present invention is applied to the exhaust valve 1 has been described, but the present invention can be applied to an intake valve that opens and closes an intake port. It is also applicable to 3-valve and 4-valve engines as well as 2-valve engines.

[0026]

[Effect of the device]

 As described above, according to the present invention, the inner spring repeatedly compresses and expands due to elastic return as the engine runs, and the other end of the inner spring whose one end is restricted in the winding direction is rotated in the winding direction. Repeatedly rotate in one direction and rotate in the opposite direction. The spring retainer elastically contacting the other end of the inner spring rotates in one direction by a predetermined amount in response to a difference in frictional contact force between the inner spring when it is compressed and when it is elastically expanded. Therefore, the valve continues to rotate in one direction together with the spring retainer, and it is possible to prevent uneven wear around the valve.

From a structural point of view, since the inner spring is added and the mass of the additional parts is small, the increase in the inertial mass of the valve train is smaller than in the past, and the engine can be rotated at high speed. Suitable. In addition, since the number of additional parts is small, there is little operation loss and high reliability can be obtained.

Further, according to the procedure in which the ring-shaped ratchet is added to the spring receiving portion of the spring retainer, the spring retainer surely rotates in one direction when the inner spring is compressed, so that higher reliability can be obtained. ..

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of a valve rotator for an engine according to the present invention.

FIG. 2 is an enlarged sectional view of a main part of a second embodiment of the present invention.

FIG. 3 is a sectional view of a conventional example of a valve rotator.

[Explanation of symbols]

 1 exhaust valve 2 cylinder head 2a spring receiving part 3 exhaust port 4 stem guide 5 cotter 6 spring retainer 6a spring receiving part 6b spring receiving part 6c ratchet 7 valve spring 7a outer spring 7b inner spring 8 valve seat 9 rocker arm 10 knock pin

Claims (2)

[Scope of utility model registration request] 1. A spring retainer connected to a valve stem end via a cotter, and a valve spring biasing the valve in a closing direction via the spring retainer, the valve springs having the same winding direction. The inner spring and the outer spring are arranged inside and outside of the cylinder head. A valve rotator for an engine, characterized in that the other end is elastically brought into contact with a spring retainer so as to be freely rotatable in the winding direction. 2. The spring retainer of the spring retainer, to which the other end of the inner spring elastically contacts, has a ring-shaped ratchet whose other end extends over the ridge when the inner spring is extended. An engine valve rotator according to claim 1.