JPS6361704A - Adjusting device for air intake and exhaust timing in engine - Google Patents

Abstract

PURPOSE:To adjust the timing of the opening and closing of section and exhaust valves by swinging the auxiliary pulleys of each bank of a vee-engine in a body by means of belts driven by a crank shaft in rotating valve driving dam shafts for suctioning and exhausting provided on each bank. CONSTITUTION:Suction cam shafts 14 and exhaust cam shafts 15 are provided to each bank of a vee-engine and are rotated by toothed belts 19 driven by a crank shaft 6. Auxiliary pulleys 21 are installed between the suction cam shafts 14 and exhaust cam shafts 15 respectively, and each of the auxiliary pulleys 21 for right and left banks is rotatably fixed to the swing arms 23 swinging around shafts 24. The two swing arms 23 are connected to each other with a rod 31 for allowing the two auxiliary pulleys 21 to be swung in a body while the shaft 24 of the left side bank is rotated through a wire 36 by the rotation of a step motor 34. When the two auxiliary pulleys 21 are swung anticlockwise in the running of the engine at low speed, the respective phases of the suction cam shaft 14 and exhaust camshaft 15 are deviated from each other for reducing the overlap in timing of the suction and exhaust valves.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a V cylinder having two cylinder rows arranged in a V-shape.
The present invention relates to an intake/exhaust timing adjustment device for a type engine that can adjust the so-called overlap timing, in which the intake valve and the exhaust valve open at the same time, to be large or small.

[Conventional technology and its problems]

Conventionally, as a device for adjusting the valve opening overlap amount of the intake and exhaust valves by changing the opening/closing timing of the intake and exhaust valves, a device has been used to adjust the valve opening overlap amount of the intake and exhaust valves. A technique is known in which a timing belt is wound between the camshafts and the part wound around one side of the camshaft is rotated from one side to the other by an outer rocker arm (
For example, Japanese Patent Laid-Open No. 58-134629).

However, in order to apply such technology to a V-type engine, it is necessary to prepare an actuator for each cylinder row, which would complicate the structure of the valve train and increase the weight of the vehicle. There is a problem in that it is difficult to improve accuracy and increases manufacturing costs.

[Object of the invention, summary of means for solving the problem] The purpose of the present invention is to solve the above-mentioned problems, have a simple structure, and accurately control each cylinder row.
A camshaft and an exhaust camshaft are provided in parallel to the crankshaft in two rows of cylinders arranged in a shape, and a camshaft is provided between each cam gear provided on both camshafts and a timing gear provided on the crankshaft. The winding winds the transmission means, and the winding pulls the transmission means inward through the space between the exhaust camshaft and the intake camshaft, and bears the transmission means on a swinging arm supported on the engine body via an auxiliary pulley. The present invention is characterized in that at least one of the swinging arms is connected to a swinging means that operates according to the operating state of the engine, and the swinging arms of both cylinder rows are connected by a link.

[Effect]

When the speed of the engine increases, the swinging arms of both cylinder rows are rotated by the swinging means, and one of the auxiliary pulleys supported by the swinging arm tightens the toothed belt, which is the transmission means, and the other As a result, the inner camshafts of both cylinder rows are simultaneously advanced or retarded by a predetermined angle, resulting in a period in which the intake and exhaust valves open at the same time, so-called intake and exhaust valve overlap. The period changes in size.

〔Example〕

Hereinafter, the present invention will be explained with reference to the illustrated embodiment. In the figure, 1 is a V-type six-cylinder engine, and on the upper surface of the cylinder block 2 are two cylinder rows R each having three cylinders.
, L are provided. A combustion chamber 5 consisting of a cylinder block 2, a cylinder head 3, and a piston 4 is formed in each cylinder row R, L, and the combustion chamber 5 constitutes a cylinder.

6 is a crankshaft, and 7 is a connecting rod.

Each combustion chamber 5 is connected to an intake passage 9 via an intake valve 8 and an exhaust passage 11 via an exhaust valve 10. The intake passages 9 of each cylinder row R, L are arranged inside the V bank, and the exhaust passages 12 are arranged outside.

14 is an intake camshaft that opens and closes the intake valve 8; 15 is an exhaust valve 1;
As shown in FIG. 1, an intake cam gear 16 and an exhaust cam gear 17 are attached to both camshafts 14 and 15. A toothed belt 19 serving as a transmission means is wound around each of the cam gears 16 and 17 and a drive gear 18 attached to the crankshaft 6, and these belts are driven by the crankshaft 6. Note that a clockwise arrow shown outside the crankshaft 6 indicates the direction of rotation of the crankshaft 6.

Therefore, in this invention, the toothed belt 19 is wrapped around the outer surfaces of both camshafts 14 and 15, and is drawn inward through the space between them, through which the auxiliary pulley 21 having a smooth outer surface is inserted. has been done. Auxiliary pulley 2
1 is rotatably supported by a boss 22 protruding from a swinging arm 23, as shown in FIGS. 4 and 5.
3 is rotatably supported on the side surface of the cylinder head 3 by a port 24 and a ball bearing 25. In addition, the swinging arm 2
3 prevents the toothed belt 19 from lifting due to tension as follows. That is, a long hole 26 is formed in the swinging arm 23, and a flanged spacer 28 made of synthetic resin, which is also attached to the side surface of the cylinder head 3 with a bolt 27, is loosely fitted therein, and is also fitted with a washer 29. A swinging arm 23 is slidably held between them. In addition, the swinging arm 23
Further, the lower surface of the other side is supported by a projection 30 that projects toward the side surface of the cylinder head 3.

Reference numeral 31 denotes a rod that connects the swinging arms 23, 23 of each cylinder row R, L.

Reference numeral 32 denotes a swinging means for swinging the swinging arm 23 according to the operating state of the engine, and for example, it is connected to the swinging arm 23 as shown in FIG. 1 or to the rod 31 as shown in FIG. be done.

That is, a pulley 33 is attached to the swinging arm 23 around the axis of the bolt 24, and the pulley 33 is connected to the other pulley 35 fixed to the axis 34 of a step motor (not shown) that operates in response to changes in engine speed. They are connected by a Bowden wire 36. Thus, when the other step motor rotates, the swing arm 23 rotates left and right accordingly.

In another embodiment, a rank 38 is interposed in the middle of the rod 31, and a pinion 39 that meshes with the rank 38 is formed on the shaft of the step motor (not shown) whose rotation is controlled according to the operating state of the engine. It is something.

In addition, in the figure, 40 is the tension wheel of the toothed belt 19.
It is pressed against the outer surface of the belt 19 by a spring 41.

Therefore, while the speed of the crankshaft 6 is low, the step motor rotates counterclockwise, and rotates the pulley 33 and the swinging arms 23 of the left and right cylinder rows R and L connected thereto in the same direction. let Therefore, the auxiliary pulley 21 strengthens the tension of the toothed belt 19 in the left cylinder, and loosens the tension in the right cylinder, so that the part 19a stretched across both cylinders moves from the right cylinder R side to the left cylinder. and relatively rotate the intake cam gears 16 of both cylinders counterclockwise.
The intake camshaft 14 connected to this is rotated in the same direction to delay the opening/closing timing of the intake valve 8. Therefore, the preset overlap period of the intake and exhaust valves is reduced.

When the speed of the crankshaft 6 reaches a higher speed than expected, the step motor rotates clockwise, causing the pulley 33 and the swing arms 23 of the left and right cylinder rows R and L connected thereto to rotate in the same direction. . As a result, the opening/closing timing of the intake valve 8 is advanced, contrary to the above. Therefore, the preset overlap period of the intake and exhaust valves increases.

〔Effect of the invention〕

As described above, this invention has two cylinder rows R and L on the left and right.
The winding that connects the exhaust camshaft and the intake camshaft is arranged inside both cylinder rows by pulling the transmission means inward through the space between the two camshafts and simultaneously tensioning or relaxing it with an auxiliary pulley. This is to advance or retard the intake camshafts by a predetermined angle at the same time, thereby controlling the overlapping period of the intake and exhaust valves.

Therefore, the intake and exhaust timings of the left and right cylinders can be accurately synchronized and adjusted, and the actuator (step motor) can be shared by both cylinders, which has the effect of simplifying the structure.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a front view showing the valve train of a V-type engine, FIG. 2 is a sectional view showing the structure of the engine body, and FIG. An enlarged front view showing the main parts, Fig. 4 is a sectional view taken along IV-■, and Fig. 5 is taken along V-V.
The sectional view and FIG. 6 are front views corresponding to FIG. 1 showing another embodiment. 14...Intake camshaft, 15...
Exhaust camshaft, 19...Toothed belt, 21...
... Auxiliary pulley, 23 ... Swing arm, 32.
・・・・Swinging means.

Claims (4)

[Claims] (1) A camshaft and an exhaust camshaft are provided in parallel to the crankshaft in two cylinder rows arranged in a V shape, and each cam gear is provided on both camshafts and a timing gear is provided on the crankshaft. A winding transmission means is wound between the exhaust camshaft and the intake camshaft, and the winding transmission means is drawn inward through the exhaust camshaft and the intake camshaft, and is bearing on a swinging arm supported on the engine body via an auxiliary pulley. An engine intake/exhaust timing adjustment device in which at least one swinging arm is connected to a swinging means that operates according to the operating state of the engine, and the swinging arms of both cylinder rows are connected by a link. (2) The engine intake/exhaust timing adjusting device according to claim 1, wherein the swinging means is provided in the middle of the link. (3) The engine intake/exhaust timing adjusting device according to claim 1, wherein the swinging means is connected to one of the swinging arms. (4) The engine intake/exhaust timing adjusting device according to claim 1, wherein the swinging means is connected to one of the swinging arms via a Bowden wire.