JPS63306227A - Coupling structure between valve body and valve stem - Google Patents

Abstract

PURPOSE:To prevent a valve body from vibrating by installing a pin, enterable into a dead-end groove from a through groove on a valve port inner wall, on the circumference of a valve stem projectingly, in case of an on-off timing control valve for an exhaust port. CONSTITUTION:A recess 24 ranging to a shaft hole 23 is formed in one end face of a valve body. In a valve port inner wall, there are provided with a through groove 25, which extends as far as the other end face of the valve body 17 from a bottom surface of the recess 24, and a dead-end groove 26 extending as far as an intermediate part of the shaft hole 23 from the bottom surface of the recess 24. A pin 27, enterable into the dead-end groove 26 from the through groove 25 by way of the recess 24, is projectingly installed on the circumference of a valve stem 19. A lock collar 32 is screwed in this valve stem tight and the pin 27 is kept in a state of contact with a blind part of the dead-end groove 26. In such manner, any lost motion lying between the valve body and the valve stem is brought to naught, thus the valve body can be prevented from vibrating.

Description

DETAILED DESCRIPTION OF THE INVENTION A.9 OBJECTS OF THE INVENTION (1) Industrial Application Field The present invention relates to a coupling structure between a valve body having a shaft hole and a valve shaft fitted into the shaft hole.

(2) Prior Art Conventionally, in such a coupling structure, the valve shaft is spline-fitted into the shaft hole of the valve body.

(3) Problems to be Solved by the Invention In the conventional structure, play may occur between the valve body and the valve stem due to unavoidable backlash at the spline fitting portion, and the valve body may vibrate.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a coupling structure that allows a valve body and a valve shaft to be coupled without play and is easy to assemble.

B1 Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention forms a concave portion connected to the shaft hole on one end surface of the valve body having the shaft hole, and A through groove that extends from the bottom surface to the other end surface of the valve body, and a dead end groove that extends from the bottom surface of the recess to the middle part of the shaft hole and ends in a dead end are provided on the inner wall of the valve hole, while making it possible to insert and remove it from the shaft hole. A pin that can enter the dead-end groove from the through-groove through the recess is protruded from the outer periphery of the valve shaft to be inserted, and a lock is provided to hold the pin in contact with the dead-end portion of the dead-end groove. It is characterized by the collar being screwed onto the valve stem.

(2) Effect According to the above configuration, by inserting the valve stem into the shaft hole of the valve body, rotating it, and pulling it back, the pin is brought into contact with the dead end part of the dead end groove from the through groove through the recessed part. Since the contact state is maintained by the lock collar which is screwed and tightened onto the valve shaft, the valve body and the valve shaft can be connected without play.

(3) Embodiment Below, an embodiment of the present invention will be explained with reference to the drawings. First, in FIGS. 1 and 2, a two-stroke engine 2 mounted on a motorcycle 1 is installed in the upper part from the crankcase 3 and in front of the vehicle. The first cylinder block 41 and the second cylinder block 42 respectively protrude from the cylinder block 41 and 42, and are configured in a V-shape.

First cylinder block 41 system and second cylinder block 4
Since the structure is basically the same as that of the □ system, only the structure of the first cylinder block 41 system will be explained.

The cylinder hole 5 of the cylinder block 41 has a piston 7 connected to the crankshaft 6 supported by the crankcase 3.
are slid together to define a combustion chamber 8 between the cylinder head 9 and the upper surface of the piston 7.
is tied to the top of the

An ignition plug 10 having an electrode facing the combustion chamber 8 is hinged to the cylinder head 9.

A carburetor 11 is attached to the crank chamber 3 inside the crank case 3 via a reed valve (not shown), and air-fuel mixture is supplied from the carburetor 11 to the crank chamber 3a during the upward stroke of the piston 7. .

Further, on the inner wall of the cylinder 5, a scavenging boat 12 connected to the crank chamber 3a and an exhaust port 1 connected to the exhaust pipe 14 are provided.
3 is open, and these boats 13 and 14 are opened and closed by the peripheral wall of the piston 7.

That is, in the downward stroke of the piston 7, the exhaust port 13 is first
is opened to discharge combustion gas from the combustion chamber 8 , and then the scavenging boat 12 is opened to force-feed the air-fuel mixture from the crank chamber 3 to the combustion chamber 8 . That is, scavenging is performed. This scavenging air is transferred to the scavenging boat 12 by the piston 7 as it moves upward.
continues until the IJF is closed again, and after the scavenging is finished, the IJF
Air boat 13 is closed. Therefore, exhaust port 1
The upper edge of the opening on the cylinder hole 5 side of No. 3 determines the opening/closing timing of the exhaust port 13, in other words, the opening period.

A control valve 15 is provided at the exhaust port 13 to control the opening/closing timing of the exhaust port 13. This control valve 15 is connected to a cylinder hole 5 of the exhaust port 13, as shown in FIG.
A pair of valve bodies 17, 17 and their boss 17a are arranged to sandwich a reinforcing wall 16 that connects the upper and lower walls at the center of the side opening.

17a and a single valve shaft I9.

The connection structure between the valve bodies 17, 17 and the valve shaft 19 will be described later.

The bosses 17a, 17a of the valve body 17.17 abut against each other behind the reinforcing wall 16, and their tip surfaces are formed into an arcuate surface that can be continuous with the inner peripheral surface of the cylinder hole 5. Further, the valve shaft 19 is connected to the cylinder block 4. Both ends are rotatably supported by a bag-shaped bearing hole 18 formed in the bearing hole 18 and a penetrating bearing hole 18''.

An operating lever 21 is fixed to the outer end of the valve shaft 19 by a nut 22. When the valve shaft 19 is reciprocated and rotated via this operating lever 21, the valve bodies 17, 17 are moved to the fully open position where they are retracted to the storage recess 20 connected to the upper edge of the opening on the cylinder hole 5 side of the exhaust bow 13, and the exhaust The opening/closing timing of the exhaust port 13 can be adjusted by moving between the fully closed position (the state shown in FIG. 2) where a prescribed amount is exposed from the upper edge of the opening of the exhaust port 13 on the cylinder hole 5 side.

Now, the connection structure between the valve bodies 17, 17 and the valve shaft 19 will be explained with reference to FIGS. 3 and 4.

The boss 17a of each valve body 17 having the shaft hole 23 has an annular recess 24 that opens at one end surface on the bag-shaped bearing hole 18 side and is connected to the shaft hole 23, and an inner surface that faces each other of the shaft hole 23. A pair of through grooves 15.15 run in the axial direction over the entire length, and the opposing inner surfaces of the shaft hole 23 are arranged at different positions from the through grooves 25.25 from the bottom surface of the recess 24 to the middle part of the shaft hole 23. A pair of dead ends 26, 26 are provided running in the direction.

On the other hand, the valve stem 19 has a through groove 25.
25 and two pins 27.27 are mounted diametrically through and capable of selectively engaging the dead grooves 26.26.

In that gap, between the two pins 27°27, the valve shaft 19 is attached to the cylinder block 4. both pins 2T, 2 in the fixed position supported by
A spacing is provided that allows the T to abut against the dead ends of the dead end grooves 26.26 of both valve bodies 17.17.

Further, the valve shaft 19 has a small diameter journal 28 supported in the bearing hole 18 at one end thereof, and a small diameter threaded shaft 29 at the other end. Further, on the outer peripheral surface of the valve stem 19, a screw 30 is carved between the screw shaft 29 and the pin 27 on the side close to it, and an annular groove 31 is carved between the screw 30 and the screw shaft 29. Ru. The valve stem 19 is attached to the screw 30.
A lock collar 32 supported in the bearing hole 18' is screwed into the other journal, and a minus groove 33 for engaging a special tool is cut in the end surface of the lock collar 32.

When connecting the pair of valve bodies 17, 17 and the valve shaft 19, the pair of valve bodies 17, 17 are first housed in the storage recess 20 of the cylinder block 41, and then the journal 28 is placed at the top. The valve stem 19 is sequentially inserted into the bearing hole 18', the shaft hole 23, 23 and the bearing hole 18. At that time, a pair of pins 2
7.27 is to match the through groove 25.25 of the valve body 17.17, and when the journal 28 is fitted into the bearing hole 18, the pins 27.27 are aligned with the corresponding through groove 25.25.
and reaches the recess 24.24.

Then, rotate the valve stem 19 by an appropriate angle to align the pins 27°27 with the dead-end grooves 26.26, then pull back the valve stem 19 and place the pins 27.27 into the dead-end parts of the dead-end grooves 26.26. After that, the lock collar 32 is screwed onto the screw 30 and tightened.

In this way, the lock collar 32 cooperates with the pins 27.27 to sandwich the valve bodies 17, 17, so that the valve body 17.17 and the valve shaft 19 can be connected without play (therefore, the valve body IT, A control valve 15 is obtained in which the control valve 17 does not vibrate.

After the above connection, the annular groove 31 of the valve shaft 19 has a bearing hole 1B'.
A circlip 35 is locked in a seal housing 34 connected to the outer end of the valve shaft 1.
An oil seal 36 is fitted in close contact with the outer periphery of 9. Finally, the nut 22 is screwed onto the threaded shaft 29 to fix the operating lever 21 onto the valve shaft 19.

Next, a specific usage example of the control valve 15 in the two-stroke engine 2 will be explained with reference to FIG.

Engine 2 extremely low speed rotation range A-B (1000-1750
When the control valve 15 is in the half-open state (rpm), the opening period of the exhaust port (13) becomes considerably longer than when it is fully closed, so the amount of fresh air blown into the exhaust port (13) is slightly larger (
However, in order to compensate for the resulting drop in output, the opening of the throttle valve in the carburetor 11 is inevitably increased, so the scavenging effect is enhanced, irregular explosions do not occur, and the low speed rotational state can be stabilized. can.

Next, when moving to the low speed rotation range B-C (1750 to 3000 rpm), the control valve 15 is fully opened, so the effective opening area of the exhaust port 13 becomes maximum. By the way, in this rotation range, as mentioned above, the exhaust pipe 14 is
A high-order positive pressure wave generated inside exhaust port 1 near the end of scavenging.
3, the positive pressure wave acts on the exhaust port 13 which has the maximum opening, and the atrium during scavenging effectively pushes the gas back into the combustion chamber 8, increasing the air supply efficiency and increasing the output (direction). −
It can cause a person to die. Therefore, the acceleration performance of the engine 2 from a low speed state is improved.

In the medium speed rotation range C=D (3000 to 6000 rpm), the control valve 15 is fully closed, so the exhaust port 13
The opening period is minimized, and the blow-through of fresh air to the exhaust port 13 can be suppressed as much as possible.

When moving to the high speed rotation range D=E (6000~loooOrpm), the control valve 15 is opened in accordance with the increase in the engine rotation speed N, so the opening period of the exhaust port 13 increases accordingly, and the exhaust and scavenging air is constantly maintained. is carried out sufficiently and high output can be obtained.

C1 Effects of the Invention As described above, according to the present invention, a recess connected to the shaft hole is formed on one end surface of the valve body having the shaft hole, and a through groove extending from the bottom surface of this recess to the other end surface of the valve body is formed. The inner wall of the valve hole is provided with a dead-end groove that extends from the bottom surface of the concave portion and ends at the middle part of the shaft hole, while the through-groove is provided on the outer periphery of the valve shaft that is removably inserted into the shaft hole. A pin that can enter the dead-end groove through the four parts is provided protruding from the bottom, and a lock collar is screwed onto the valve shaft to hold the pin in contact with the dead-end part of the dead-end groove, making it extremely simple. The valve body and the valve stem can be joined together without any looseness through a proper assembly operation, and vibration of the valve body can be reliably prevented.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a side view of a motorcycle equipped with the structure of the present invention in an engine control valve;
Figure 2 is an enlarged vertical side view of the main parts of the engine, Figure 3 is an enlarged cross-sectional view taken along the line ■-■ in Figure 2, Figure 4 is an exploded perspective view of the control valve, and Figure 5 is an exploded perspective view of the control valve J1. It is a control map. 15... Control valve, 17... Valve body, 17a... Boss, 19... Valve stem, 23... Shaft hole, 24... Recessed part,
25... Through groove, 26... Dead end groove, 27... Pin, 30... Screw, 32... Lock collar patent applicant Honda Motor Co., Ltd. agent Patent attorney Kendai Ochiai 3rd Illustrated sister big sister Kazuichi

Claims (1)

[Claims] A recess connected to the shaft hole is formed on one end surface of the valve body having the shaft hole, and a through groove extending from the bottom surface of the recess to the other end surface of the valve body, and a through groove extending from the bottom surface of the recess at an intermediate portion of the shaft hole. A dead end groove is provided on the inner wall of the valve hole, and a pin that can enter the dead end groove from the through groove through the recess is protruded on the outer periphery of the valve shaft that is removably inserted into the shaft hole. A coupling structure between a valve body and a valve shaft, in which a lock collar is screwed and tightened to the valve shaft to hold the pin in contact with the dead end portion of the dead end groove.