JPS6278415A - Tappet valve device for internal combustion engine - Google Patents

Abstract

PURPOSE:To lessen the rattling of a tappet valve mechanism due to the clearance of connecting members and the backlash of a gear by opening and closing suction and exhaust passages on the oscillation of a rotary valve via the connecting members and loading the rotary valve through a specific means. CONSTITUTION:When a cam shaft 43 and a cam 45 have been turned via a power transmission mechanism 44 on the rotation of a crank shaft, a rocker arm 39 circumscribed by a cam 45 oscillates intermittently. Then, a secondary segment gear 41 gives 90 deg. intermittent oscillation via a primary segment gear 40, rotary valve mechanisms 16 and 17 move likewise via a drive shaft 52 and an Oldham's coupling 33 and suction and exhaust passages are opened and closed by rotary valves 18 and 19. In this case, the intermittent oscillation of the rotary valves 18 and 19 transmits rotation to a shaft body 59 via each connection member 66, 64 and 62 and an assist spring 68 is thereby distorted. Consequently, rattling arising on the Oldham's couplings 20 and 23 and the segment gears 40 and 41 can be lessened.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a valve train for an internal combustion engine.

(Prior art and its problems) In general, a valve train for an internal combustion engine includes a rotary valve provided in the intake and exhaust passages, and a valve train mechanism that opens and closes the rotary valve. The valve mechanism is connected by an Oldham joint that corrects the misalignment of the rotation axes of the two.

As mentioned above, Oldham's joints always have a clearance between the engaging groove of the rotary valve and the engaging protrusion of the Oldham's joint in order to compensate for misalignment, and when meshing gears are used in the valve mechanism, backlash can cause backlash. There is. As a result, backlash occurred between the Oldham joint and the rotary valve, and an impact load was applied to the engagement groove of the rotary valve during one intermittent rocking motion, impairing the functionality and durability of the rotary valve.

(Object of the invention) The present invention has been made in view of the above circumstances, and its purpose is to prevent the Oldham joint (connecting member) and the rotary valve from collapsing, which conventionally occurs when a one-rotation valve swings. The objective is to improve the functionality and durability of the rotary valve by reducing the backlash caused by the clearance between the valves and the backlash of the gears in the valve mechanism, eliminating the impact load on the rotary valve (when the rotary valve is engaged), and improving the functionality and durability of the rotary valve.

(Means for Solving the Problems) In order to achieve the above object, the valve operating device for an internal combustion engine according to the present invention is arranged separately in the intake and exhaust passages communicating with the combustion chamber of the internal combustion engine. a rotary valve that opens and closes each of these passages, a valve operating mechanism that opens and closes the rotary valve by intermittent rocking motion of the rotary valve in conjunction with the movement of the piston, and a valve mechanism that drives the rotary valve to open and close the rotary valve. , or a connecting member that connects the rotary valve and the drive shaft of the valve mechanism and absorbs misalignment of their rotational axes, and absorbs looseness at a connecting portion between the connecting member and the connecting member during rocking motion of the one-turn valve. and means for doing so.

(Function) When the rotary valve swings through the connecting member by the valve mechanism to open and close the intake and exhaust passages, the means for absorbing backlash creates a load on the rotary valve for the movement, and this load is This reduces the backlash of the valve train due to the clearance between the rotary valve and the connecting member and the backlash of the gears of the valve train.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows the main parts of an internal combustion engine to which a valve train according to the present invention is applied. A cylinder rod 11 is mounted and fixed on a cylinder block 10 of the internal combustion engine, and a screw 1 is attached to the cylinder head 11. - An intake passage 14 and an exhaust passage 15 are provided which open into the combustion chamber 13 formed by the upper end surface of the cylinder head 12 and the recess 11a of the cylinder head 11. A rotary valve mechanism 16,17 is provided at the end.

The rotary valve mechanism 16, 17 includes two rotary valves 18, 19, and the rotary valves 18 and 19 are connected by an Oldham joint 20, which is a connecting member.

One rotary valve 18 is formed with a through hole 21, and side walls 22, 23 of the rotary valve 18 are formed with engagement grooves 22a, 23a that are 90 degrees out of phase with each other.

In addition, a through hole 24 is formed in the other rotary valve 19.
Engagement grooves 25a and 26a are formed in the side walls 25 and 26 of the rotating body 19, and the engagement grooves 25a and 26a are 90 degrees out of phase with each other.

The Oldham joint 20 is connected to the intermediate connecting member 2 as shown in FIG.
Joint members 29 and 30 are inserted into the cross grooves 28 of No. 7 and slide with a phase shift of 90 degrees from each other.

One joint member 29 of the Oldham joint 20
is engaged with the engagement groove 22a of the rotary valve 18, and the Oldham joint 2
0 into the engagement groove 2 of the rotary valve 19.
5a, both rotating bodies 18, 19 are connected.

The rotary valve 18 of the rotary valve mechanism 16 and 17 is the rotary valve drive mechanism 3
It is connected to the drive shaft 32 of No. 1 via an Oldham joint 33 which is a connecting member. This Oldham joint 33 consists of a joint member 34 on an intermediate member 27' and a joint portion 35 formed on the drive shaft 32, and the joints 1 to 34 of the Oldham joint 33 are engaged with the engagement groove 23a of the rotary valve 18. There is. The rotary valve drive mechanism 31 is connected to the cylinder head 11
The rocker arm 37 is swingably attached to the outer surface of the rocker arm 37 by a support shaft 36, and a segment gear 38 is provided at the 11th part of the rocker arm 37. A drive shaft 32 is supported in the support hole of the cylinder head 11 via a bearing 40, and a segment gear 39 is attached to the outer end of the drive shaft 32. It meshes with the Further, a camshaft 41 is provided in the support hole of the cylinder rod 11, and the camshaft 41 is connected to a crankshaft (not shown) via a power transmission mechanism 42.
is attached, and the cam 43 circumscribes the cam surface 44 of the rocker arm 37.

Further, the cylinder head 11 is provided with a return spring mechanism 45. The return spring mechanism 45 includes a base member 46 attached to the side end of the cylinder head 11.
The base member 46 is provided with a guide member 47.
is attached, a contact member 48 is slidably provided on the guide member 47, and a return spring 5o is interposed between the spring receiving portion 49 of the contact member 48 and the base member 46, The contact member 48 is urged toward the rocker arm 37 by the return spring 5o, and the end surface of the contact member 48 is in contact with the contact surface 51 of the rocker arm 37 on the opposite side to the cam surface 44.

Further, a bracket portion 52 is formed on the cylinder head 11, and a stopper bolt 53 is attached to this bracket portion 52.
The stopper bolt 53 is in contact with the side end surface of the segment gear 39.

Moreover, this segment gear 39 is 90°
It is designed to perform a degree of rocking motion.

The cylinder head 11 is provided with an accommodating part 56 that accommodates an assist spring mechanism 55 as a load generating means, which is arranged in line with the accommodating part 54 of the rotary valve mechanism 16.17. It is.

The assist spring mechanism 55 includes a shaft body 57,
A large diameter portion 58, a flange portion 59, and a joint portion 60 are formed on one end side of the shaft body 57, and a locking groove 61 is formed in the large diameter portion 58.
is the provision. The joint portion 60 is slidably inserted into the cross groove 63 of the intermediate connecting member 62, and the joint portion 60 is slidably inserted into the cross groove 63 of the intermediate connecting member 62.
A joint member 64 that is 90 degrees out of phase with the joint portion 60 is slidably inserted into the cross groove 63 of the rotary body 19.
6a. Further, the end portion of the shaft body 57 is inserted into a bearing 65 provided on the end wall portion of the accommodating portion 56.

Further, an assist spring 66 is provided in the accommodating portion 56, one end 66a of the assist spring 66 is inserted and locked into the locking groove 61 of the shaft body 57, and the other end 66b of the assist spring 66 is accommodated. It is inserted and locked into a locking groove 67 formed in the wall of the portion 56.

Next, the operation will be explained. When the camshaft 41 rotates via the power transmission mechanism 42 due to the rotation of the crankshaft and the cam 43 is rotated, the rocker arm 37 with which the cam 43 is circumscribed
is intermittently rocked by the restoring action of the return spring 50.

Due to the intermittent rocking motion of the rocker arm 37, the segment gear 39 performs an intermittent rocking motion of 90 degrees via the segment gear 38, and the rotary valve mechanism 16, 17 performs an intermittent rocking motion via the drive shaft 32 and Oldham joint 33. During the movement, the suction and exhaust passages 14.15 are opened and closed by the one-turn valves 18.19.

In this case, some play in the rotational direction occurs due to backlash due to the meshing of the segment gears 38 and 39 and clearance of the Oldham joint 33 and 20, but this play is caused by the assist spring mechanism 55.
is reduced by

That is, the joint member 64, the intermediate connecting member 62
Rotation is applied to the shaft body 57 via the joint portion 6o, and the assist spring 66 is twisted. This creates a force in the assist spring 66 that resists twisting.
This resistance force propagates to the Oldham joint 20.33 and the segment gears 38.39, and acts to reduce backlash.

(Effects of the Invention) As detailed above, the valve train for an internal combustion engine according to the present invention is arranged separately in the intake and exhaust passages communicating with the combustion chamber of the internal combustion engine, and opens and closes each of these passages. a rotary valve that rotates, a valve drive mechanism that opens and closes the rotary valve by intermittent rocking motion of the rotary valve in conjunction with the movement of a piston, and a valve drive mechanism that drives the rotary valve to open and close the rotary valve, or the rotary valve and the rotary valve. A connecting member that connects the drive shaft of the mechanism and absorbs misalignment of their rotational axes, and a means for absorbing looseness of the connecting portion with the connecting member during rocking motion of the rotary valve. This is a characteristic feature. .

Therefore, when the rotary valve uses a swinging motion to open and close the intake and exhaust passages via the connecting member by the valve operating mechanism, a load is generated on the rotary valve due to the movement due to the means for absorbing backlash, and this load is This is propagated to the members and the valve train, and the looseness of the valve train due to the clearance of the connecting members and the backlash of the gears of the valve train is reduced.

This eliminates the impact load on the engaging groove portion of the rotary valve, which conventionally occurs, and improves the functionality and durability of the rotary valve.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of the main parts of an internal combustion engine to which the valve train according to the present invention is applied, Fig. 2 is an explanatory diagram of the configuration of the drive section ρ of the valve train, and Fig. 13 is an embodiment of the present invention. 4 is a longitudinal sectional view thereof, FIG. 5 is an explanatory view of the structure of the rocker arm portion, and FIG. 6 is an exploded perspective view of the connecting member. 16.17... Rotary valve mechanism, 18.19... Rotary valve. 37...Rocker arm, 38.39...Segment gear, 66...Assist spring.

Claims (1)

[Claims] Rotary valves are provided separately in intake and exhaust passages communicating with a combustion chamber of an internal combustion engine to open and close each passage, and the rotary valves are each intermittently oscillated in conjunction with the movement of a piston. a valve drive mechanism that opens and closes the rotary valve; a connecting member that connects the rotary valves or the drive shaft of the rotary valve and the valve drive mechanism to absorb misalignment of their rotation axes; A valve train for an internal combustion engine, comprising means for absorbing rattling of a connecting portion with the connecting member during rocking motion of the rotary valve.