JPS60261909A - Driving mechanism for suction rotary valve - Google Patents

Abstract

PURPOSE:To enable adjustment of tension of the driving belt of a rotary valve, by a method wherein idlers are attached to an arm which is regulated through slide of it over a base. CONSTITUTION:A crank shaft 1 and the shaft of a rotary valve are disposed so that the two shafts cross each other at right angles, and the two shafts are intercoupled through a belt 4. Idlers 6 and 7 are attached to an arm 5 which can be adjustably attached to a base 8, the intermediate of the belt 4 is supported to the idlers 6 and 7, and the belt runs in a solid manner therearound. The mounting position of the arm 5 is adjusted by means of an adjusting screw 10, and is fastened by means of a tightening bolt 9. As noted above, adjustment of the mounting position of the arm 5 results in adjustment of tension of the belt 4.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a drive mechanism for an intake rotary valve that uses a timing belt as a power transmission medium, and particularly to a drive mechanism that can adjust the tension of the timing belt.

(Prior art) If the intake rotary valve shaft is separate from the crankshaft, the carburetor is installed near the center of the engine, and the intake rotary valve itself is installed behind the cylinder and above the crankcase, intake performance can be improved. This facilitates the design of the intake boat shape.

By the way, according to the above arrangement, the crankshaft and the rotary valve shaft are not located on the same plane, so in order to transmit the power of the crankshaft to the rotary valve shaft, the two shafts must be connected by a mechanical element such as a bevel gear. I needed to.

However, when mechanical elements such as bevel gears are used as a means of power transmission, the degree of freedom in designing the shaft position relationship is reduced, problems such as lubrication and noise arise, and the structure becomes complex, weight increases, costs increase, etc. This will cause problems.

Therefore, it has been proposed to use a lightweight and highly flexible belt as a power transmission medium, but the tension of this belt fluctuates due to assembly errors of the parts around which it is wrapped, and adjustment of the belt tension is difficult. It becomes necessary.

(Object of the Invention) The present invention has been made in view of the above circumstances, and its object is to provide an intake rotary pulp drive mechanism that can arbitrarily adjust the tension of the belt.

(Structure of the Invention) In a mechanism in which a timing belt is wound three-dimensionally between pulleys fixed to each of a crankshaft and a rotary valve shaft with an idler interposed therebetween, the arm member holding the idler is placed on the fixed side. It is characterized in that it is slidably fitted into the base member of the arm member, and an adjustment bolt, one end of which abuts the fixed side, is inserted and screwed into the arm member.

(Embodiment) - A preferred embodiment of the present invention will be described below with reference to the attached drawing 9.

FIG. 1 is a partially cutaway side view of the drive mechanism according to the present invention, and FIG.
The figure is a view taken in eight directions in the direction of the arrows in FIG. 1, and FIG. 3 is a view showing the state in which the belt is wound.

In the figure, (1) is the crankshaft of the engine, and a gear-shaped drive boot 9 (2) is fixed to the end of the crankshaft, and the drive pulley (2) and the shaft of the intake rotary valve (not shown) are fixed to the end of the crankshaft. The driven pulley shown in Figure 3 is fixed to the end (
3) In between is a timing belt with teeth engraved on its inner surface (
4) is wrapped around it. That is, this timing belt (4) is connected to the idler (8) held by the arm member (5).
, (7) are bent and wrapped three-dimensionally.

Since the drive and driven pulleys rotate in a torsional position, the idler is placed on a common tangent to each pulley to ensure rotation of the belt.

By the way, the arm member (5) that holds both the idlers (8) and (?) is connected to the fixed side base member (?) as shown in the figure.
8), and the tightening port (9) that is screwed into this is fitted into the oblong hole (8) drilled in the base member (8).
a). In addition, an arm member (5) (a long adjustment pole) (10) is inserted and screwed into the arm member (5), and one end of this is in contact with the fixed board (11) as shown in the figure. There is a loosening prevention 1 between the head and arm member (5).
The F spring (12) is compressed.

Thus, while the engine is rotating, the rotation of the crankshaft (1) is transmitted to the intake rotary valve via the drive pulley (2), timing belt (0) and driven pulley (3), causing the intake rotary valve to rotate. Driven.

By the way, the tension of the timing belt (4) is adjusted as follows.

That is, by loosening the tightening port (8) that fastens the arm member (5) to the base member (8) and turning the adjustment port (10), the arm member screws into the adjustment port (10). (5) moves in either direction relative to the base member (8). If this arm member (5) moves, for example, by Δa as shown in FIG. The tension of the belt (4) is adjusted arbitrarily by absorbing assembly errors of each part, and the gravity is always maintained at an optimum value.

(Effects of the Invention) As is clear from the above description, the present invention provides a mechanism in which a timing belt is wound between pulleys fixed to each of the crankshaft and rotary valve shaft with an idler interposed therebetween. The arm member that holds the idler is slidably fitted to the base member on the stationary side, and an adjustment port whose one end abuts on the stationary side is inserted and screwed into the arm member, so that the tension of the timing belt is reduced. can be adjusted arbitrarily.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view of the drive mechanism according to the present invention, and FIG.
The figure is a view in the direction of arrow A in FIG. 1, and FIG. 3 is a view showing how the belt is wound. In the drawing, (1) is the crankshaft, (2) is the drive pulley, (3) is the driven pulley, (4) is the timing belt, (5) is the arm member, (6), (7) is the idler, ( 8) is the base member, (9) is the tightening port, (10)
is an adjustment bolt.

Claims (1)

[Claims] In the intake rotary valve drive mechanism, a timing belt is three-dimensionally wound between a drive booby fixed to the end of the crankshaft and a driven pulley fixed to the intake rotary valve shaft end, with an idler interposed therebetween. An intake rotary valve characterized in that an arm member for holding an idler is slidably fitted into a base member on a stationary side, and an adjustment bolt whose one end abuts on the stationary side is inserted and screwed into the arm member. Drive mechanism.