SU1574872A1 - Valve gear of internal combustion engine with controllable phases - Google Patents

Abstract

The invention relates to engine-building and allows reducing wear of the rubbing pairs in the engine timing mechanism. It contains a camshaft 2, located in the cylinder head above the valves and equipped with eccentrics 1, interacting through the hinge segment with levers 7, each of which has one end interacting with the bottom surface with the valve 9, the other is fixed on the adjustable ball support 8. The connecting rod 3 is fastened with the slider 5, the hinge 4, allowing them to rotate all the way into each other. In the lower part of the slider 5 there are two rods 6, freely entering the holes made at the support end of the lever, the axes of which pass through the axis of rotation of the lever 7 and are perpendicular to the thrust surface of the slide 5. The support 8 is made with the possibility of vertical movement, which allows smooth operational change of the valve timing mechanism. To simplify the design of the camshaft 2, the intake and exhaust valve mechanisms are arranged symmetrically about a vertical axis passing through the center of rotation of the camshaft. 2 hp f-ly, 11 ill.

Description

The invention relates to mechanical engineering, in particular, engine-building, and can be used in gas distribution mechanisms.

The purpose of the invention is to reduce wear of the steam in the timing mechanism.

FIG. Figure 1 shows schematically the timing mechanism; in fig. 2–4 are sections A-A, B-B and B-B in FIG. 1, respectively; in fig. 5 — mechanism for vertical movement of the support of the pusher lever; in fig. 6 - scheme of the mechanism; in fig. 7 - the second version of the mechanism with increased rigidity; in fig. 8 - section G-Y in FIG. 7; in fig. 9 is a diagram of variable valve timing with vertical movement of the pusher arm support; FIG. 10 - the cyclogram of operation of valves of one cylinder; in fig. 11 is a diagram of the mechanism with a symmetrical arrangement of the mechanisms of the intake and exhaust valves.

The gas distribution mechanism contains an eccentric 1 (Fig. 1), which is integral with the camshaft 2, which rotates freely in the bore of the connecting rod 3. The lower right end of the connecting rod 3 is hinged 4 with the slider 5 with the possibility of free rotation until it stops at each other's surface. Two cylindrical rods 6 are tightly inserted into the slider 5, the free ends of which enter the holes at the end of the lever pusher 7. The same end of the lever pusher 7 is fixed and mounted on a ball-bearing support 8 which is located between the rods 6 (FIG. 2-3), the axial lines of the holes of the lever-pusher 7, into which the rods 6 are inserted, pass through the center of rotation of the lever-pusher 7. The rods 6 are fixed in the slider 5 so that their axes are perpendicular to the surface of the slide of the slide 5. The rods 6 move freely in the axial direction in about the hub of the lever-pusher 7. The opposite end of the lever-pusher 7 its lower surface interacts with the valve 9, the upper surface

rests on the stopper 10. A spring 11 is put on the valve 9. The ball bearing 8 is configured to vertically move, for which a special mechanism is provided (Fig. 5). Bottom

a part of the support 8 is placed in the opening of the body of the cylinder block 12 and freely moves in the axial direction. In the lower part of the support 8 there is an inclined through hole in which a special rod 13 is placed, sliding in it and fastened on both sides by cylinders 14, 15, which are placed in holes whose axes are perpendicular to the axis of the support 8. Cylinders 14, 15 have axial possibility

movements in these holes. The cylinder 14 has a loop 16 fastened together by a hinge 17 with a connecting rod 18. The connecting rod 18 encloses an eccentric 19, which rotates freely in it and is made integral with the adjusting shaft 20.

The device works as follows.

The eccentric 1 (Fig. 1} rotates with the camshaft 2. The center of the eccentric 1 moves around a circle of radius R (Fig. 6). When the center of the eccentric moves from position a 1 to position a 2 and then to position AZ, and 4, A5, the hinge 4 moves in a straight line segment from position b1 to position B2, B3, B4, B5 In the same direction the slider 5 moves with the rods 6 (Fig. 1), which freely extend from the opening of the ram arm 7. At this moment, a pro-gate of the connecting rod 3 occurs around the hinge 4 with respect to the slide 5. The pusher lever 7 at this time Rests against the upper surface in the limiter 10 and remains stationary, and with it the valve 9. When

when the center of the eccentric position a5 is reached (Fig. 6), the contact surfaces of the connecting rod 3 and the slide 5 contact. The position of a5 is determined to lie on one straight line with the position a1 and the center of rotation of the pusher lever 7 (in Fig. 6 it is marked with a dot D). When the contact surfaces of the connecting rod 3 and the slide 5 contact each other, turning them to one side relative to each other becomes impossible also with the direction of the force tending to turn the connecting rod 3 relative to the slide 5 in this direction, i.e. The connecting rod system 3 - slider 5 is a rigid lever. This is exactly what happens when the center of the eccentric moves from position a5 to position ab and then a7. Position a7 is defined as the tangency point of the tangent drawn from point D in a circle of radius R. When passing the center of the eccentric of the a5, ab, a7 positions, the connecting rod 3 - slider 5 oscillates by an angle y around point D and a simultaneous axial movement equal to distance differences a5D and a7D. The swinging movement of the lever connecting rod 3 slider 5 is transmitted to the lever pusher 7, which presses the bottom surface on the valves 9 (Fig. 1) and opens it. The angle of swing of the lever-pusher 7 is equal to y. The lower position of the end of the pusher lever 7 in FIG. b indicated by the point c7. When the eccentric center moves from position c7 to position c8 and then in c1, the push lever 7 reverses under the action of a spring 11 (Fig. 1) mounted on valve 9. In this movement, the connecting rod 3 and the slider 5 are also in contact surfaces and represent a rigid structure, since the force tending to rotate the slider 5 relative to the connecting rod 3 maintains this contact, which in turn prevents the valve 9 from closing instantaneously. When the eccentric center a1 is reached, a full cycle of operation takes place mechanization a. The impact arising from the contact of the stop surfaces of the connecting rod 3 and the slide 5 is directed perpendicularly to these surfaces and parallel to the axis of the rods b. Lever pusher 7, and consequently, valve 9, this blow is perceived.

To obtain a higher stiffness of the lever, the connecting rod 3 - slider 5 can be used several other mechanism design. Rods 6 designs are missing. The slider 5 (Fig. 7) is in direct contact with the pusher lever 7 by means of two plates with grooves into which rectangular protrusions freely enter.

along the edges of the support part of the lever pusher 7. The axes of these protrusions pass through the axis of rotation of the lever pusher 7. The resistance of the plates to the bending moment arising in the mechanism during operation is much higher than the resistance of cylindrical rods. FIG. 6 angle / 5-angle of idling, during the rotation of the distribution hall to this angle of the valve is fixed; the angle ai is the angle at which the valve opens, the angle is the angle at which the valve closes (a + C & angle of travel). As can be seen from the cti az scheme, the opening and closing times of the valve are not equal. If the camshaft rotates in the direction opposite to that shown in the diagram, then the angle a is the angle of closing, and the angle cti is the angle of opening of the valve.

Angle of idling / 5 is determined by the positions A1 and A5, which, as already mentioned, are located on the same straight line with the center of rotation of the lever-pusher 7 (point D, Fig. 9) The location of A1 and A5 is determined by the position of point D relative to point O - the center of rotation of the eccentric, angle y is the angle between the axis of the lever-pusher 7 and the axis of the rod (for a particular mechanism, the value is constant), angle gr is the angle between the axis of the rod 6 and the horizontal. Point C determines the position of the point of contact of the surface of the lever-pusher 7 with the limiter 10 (figure 1). As can be seen from the diagram (Fig. 9), with the vertical movement of the center D, the distance DO changes, the angle 1 / J changes, since the limiter 10 (figure 1) prevents the end of the push lever 7 from moving. Point C gets some axial movement, which, because of its insignificance, is not taken into account. Due to all these changes, the value of the idle angle / also changes. As seen from

the diagrams (Fig. 9) D, respectively, change the values of the angles a and as, since h # 1 + 2 + / 3 is 360 °. Therefore, when the center of rotation of the lever-pusher 7 moves vertically, the valve timing of the mechanism changes. As for the value of the swing angle of the lever-pusher that determines the valve stroke, it practically does not change. The angle y is determined as the angle between the lower tangent, drawn from point D to the circumference of the radius R of rotation of the center of the eccentric, and the straight line DA1, A5. When the point D is raised, the distance DO decreases, and the angle / increases. With increasing angle / 3, the value of angle y decreases, but at the same time with decreasing distance DO (L L1)

angle u increases. As a result, the value of the angle X practically does not change.

Structurally, the vertical interchange of the support 8 occurs as follows (FIG. 5).

When cranking the adjusting shaft 20, the eccentric 19 pivots, which pushes the connecting rod 18. The latter, in its turn, presses on the cylinder 14, which begins to move towards the support 8 and at the same time begins to move the inclined rod 13, the surface of which is It is a wedge and lifts the support O by a certain amount. During the reverse rotation of the adjusting shaft 20, all the elements move in the opposite direction, and the support 8 is lowered. The adjustment of the adjustment wheel 20 can be carried out from a manual drive directly by the operator or 6 tons of a special engine, for example, step-by-step, operating in automatic mode with feedback from the frequency of rotation of the Crankshaft of the engine.

Typically, the valve timing of the intake and exhaust valves is symmetrical (Fig. 10). Consequently, if, using the proposed mechanism, the intake and exhaust valve mechanisms are located asymmetrically on opposite sides of the camshaft, one eccentric with two connecting rods on him will be able to set the law of motion for both the intake valve and exhaust valve of a single cylinder. . eleven). This simplifies the manufacture of the camshaft. With such an arrangement of mechanisms, separate control of the valve timing of the intake and exhaust valves is easily accomplished.

Claims (3)

1. The engine timing of the internal-combustion engine with adjustable, phases containing an eccentric camshaft, a connecting rod, a lever-pusher mounted in the head of the unit on an adjustable ball bearing, a disc valve with a spring and a stop, and the connecting rod is kinematically connected to the lever-pusher, different so that, in order to reduce wear on the rubbing pairs, the kinematic connection of the connecting rod with the pusher lever is carried out using a slider, one end of which is hinged on the connecting rod and provided with an abutment, and others It is fixed on the pusher lever with the possibility of axial movement. 2. The mechanism of claim 1, wherein the slider is connected to the pusher lever by means of two cylindrical rods. 3. The mechanism of pop. 1, different from that. that the slider is connected to the pusher lever by means of two plates with grooves into which rectangular protrusions freely enter, located along the edges of the support end of the lever, the axes of which pass through the center of the ball bearing. Bb Aa 2 Fig.Z 4 a M Cfe III rsa "a AI FIG. 7 U9ut .t / Inlet Release FIG. 10 Phage. ff