JPH0129341Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a rotary valve drive device for opening and closing a rotary valve such as a butterfly valve, and in particular to a rotary valve drive device suitable for controlling an intake control valve of an internal combustion engine. Regarding equipment.

[Prior art]

The applicant of the present application first developed a rotary valve drive device that is suitable for controlling the opening and closing of an intake control valve (swirl control valve) of an internal combustion engine and that does not cause rattling over time even during long-term use. (Japanese Patent Application No. 58-041517, Japanese Patent Publication No. 170583-1983). This drive device is characterized by converting the translational motion of a drive member driven by an actuator into rotational motion of a rotary valve using a leaf spring. For this purpose, one end of the leaf spring is fixed to the drive member, and the other end is formed into a substantially cylindrical shape, and the leaf spring is linked to the valve shaft of the rotary valve via a bottomed cylindrical bearing insert made of synthetic resin. The ball joint is engaged. Furthermore, the present applicant further improved the rotary valve drive device and proposed a rotary valve drive device in which a skirt portion is formed at the lower part of the bearing insert (Utility Model Application No. 59-96949, Utility Model Application No. 61-12938). issue). This proposed device has the advantage of being able to improve the positioning accuracy of the opening of the rotary valve.

However, due to the existence of machining dimensional tolerances and assembly tolerances of the cylinder head, intake control valve, and valve drive device components, unreasonable force is applied to the fitting part of the bearing insert and ball joint, resulting in the retention of the bearing insert. Some irons have reduced force and increased sliding resistance, which has been an obstacle to smooth opening/closing control of rotary valves.

[Purpose of invention]

The present invention was devised in view of the above-mentioned problems of the prior art, and aims to provide a rotary valve drive device that can smoothly control the opening and closing of a rotary valve over a long period of time. .

[Structure of the idea]

Therefore, in the present invention, one end of a leaf spring is fixed to a driving member that is translated in translation by an actuator, and the other end of the leaf spring is formed into a substantially cylindrical shape, has a skirt portion extending downward, and has a partially spherical support. A ball joint is provided in a rotary valve opening/closing arm connected to a valve shaft of a rotary valve, in which a synthetic resin bearing insert having a substantially bottomed cylindrical shape and having a surface is fitted to the substantially cylindrical other end of the leaf spring. is rotatably fitted to the support surface of the bearing insert, the transition part from the partially spherical support surface of the bearing insert to the inner surface of the skirt portion has a radial direction for preventing the ball joint from coming off. It is characterized in that a protrusion is provided, and a predetermined clearance is provided in the vertical direction between the surface of the protrusion and the surface of the ball joint.

[Effect]

Since the vertical clearance is thus provided between the retaining protrusion and the ball joint, vertical variations in processing dimensions and assembly dimensions can be absorbed. On the other hand, variations in the radial direction are absorbed by the elasticity of the leaf spring. Therefore, excessive stress is not applied to the engagement portion between the bearing insert and the ball joint.

〔Example〕

Next, embodiments will be described with reference to the accompanying drawings.

FIG. 3 shows a case where the rotary valve drive device of the present invention is applied to an internal combustion engine. In Figure 3, 10
12 is a cylinder head, 12 is a cylinder, 14 is an intake valve, 16 is an exhaust valve, 18 is an intake port, 20 is an intake pipe, and the negative pressure chamber 2 of the actuator 22 is
4 is connected to the intake pipe 20 via a switching valve 28 that responds to an output signal from an engine speed sensor or a negative pressure sensor 26. A valve shaft 32 of an intake control valve 30 is disposed within the intake port 18 eccentrically from the intake port axis. An arm 34 is fixed to each valve shaft 32, and the tips of these arms 34 are connected to a drive member 38 via a leaf spring 36.

When the engine speed is lower than a predetermined rotation speed or when the negative pressure in the intake pipe 20 is higher than a predetermined negative pressure, the negative pressure chamber 24 of the actuator 22 is switched by the switching action of the switching valve 28. is connected within the intake pipe. As a result, negative pressure acts within the negative pressure chamber 24, causing the diaphragm 40 to move to the right, moving the drive member 38 to the right (see Figure 5), and rotating each intake control valve 30 to its maximum closed position. Make it move. At this time, the air-fuel mixture flows at high speed along one side wall of the intake port 18 as shown by arrow A, and thus a strong swirling flow as shown by arrow B is generated within the cylinder 12. As a result, the combustion speed is increased and stable combustion can be obtained.
On the other hand, when the engine speed becomes higher than a predetermined rotation speed or the negative pressure in the intake pipe 20 becomes smaller than a predetermined negative pressure, the negative pressure chamber 24 is opened by the switching action of the switching valve 28. Open to the atmosphere. As a result, the diaphragm moves to the left under the action of the spring 42, and the intake control valve 30 rotates by an angle θ in order to drive the drive member 38 to the left (FIG. 5).
It is forced to open fully. In this way, high charging efficiency can be obtained during engine high-speed, high-load operation.

As best seen in FIGS. 4 and 5, one end of each leaf spring 36 is secured to the drive member 38 by a rivet 44.
The other end 36a is wound into a substantially cylindrical shape.

As can be seen from FIGS. 4, 5, and 6, one end of an arm 34 is caulked to the valve stem 32. As shown in FIG. 6, a ball joint 48 is caulked to the other end of the arm 34. A synthetic resin bearing insert 50 is press-fitted into the substantially cylindrical end 36a of the leaf spring 36 (see FIG. 6), and is prevented from rotating by a protrusion 52. The insert 50 has a partially spherical support surface 56 below the bottomed shaft hole 54 that functions as a grease reservoir.
is formed, and a ball joint 48 is fitted within this support surface 56. bearing insert 50
A skirt portion 58 is formed at the lower part of the holder.

As shown in FIGS. 1 and 2, the skirt portion 5
8 is provided with a throttle 60 along a plane containing the axis of the ball joint 48 to allow the skirt portion 58 to expand when the ball joint 48 is snapped into the bearing insert 50. Further, at the transition portion from the support surface 56 to the skirt portion 58, a retaining protrusion 62 having a triangular cross section is provided radially inward. As can be seen in FIG. 2, these projections 62 taper off toward the slot 60. As shown in FIG. 1, the lower surface of projection 62 is at an acute angle to the axis of ball joint 48 to facilitate insertion of ball joint 48 into the opening in skirt portion 58. ing. In contrast, the upper surface of the protrusion 62 is
The ball joint 48 forms an obtuse angle with respect to the cylindrical extension part 6, making it difficult for the ball joint 48 to come off. or,
A predetermined clearance C is provided between the upper surface of the protrusion 62 and the surface of the ball joint 48.

[Effect of idea]

As mentioned above, the present invention provides a retaining protrusion that protrudes in the radial direction between the support surface of the bearing insert of the rotary valve drive device and the skirt portion, so it is possible to prevent the retaining force of the bearing insert from decreasing. . Moreover, since a predetermined vertical clearance is provided between the surface of the retaining protrusion and the ball joint, relative movement in the vertical direction between the bearing insert and the ball joint is allowed, and the cylinder head It is also possible to absorb positioning deviations due to manufacturing and assembly tolerances of the intake control valve and valve drive device components. Therefore, no unreasonable force is applied to the engagement portion between the bearing insert and the ball joint, so that the engagement portion does not wear out and frictional resistance does not increase. Therefore, the rotary valve can be smoothly driven for a long period of time.

[Brief explanation of the drawing]

Figure 1 is an enlarged cross-sectional view showing the connection between the bearing insert and ball joint attached to the end of the leaf spring, and is a view taken in the direction of the - arrow in Figure 2. Figure 2 is a bottom view of the bearing insert, and Figure 3 is a bottom view of the bearing insert. A horizontal sectional view of an internal combustion engine cylinder head showing the arrangement of the rotary valve drive device of the present invention, FIG. 4 is a plan view of the rotary valve drive device, FIG. 5 is an explanatory diagram showing the operation, and FIG. FIG. 22... Actuator, 30... Rotary valve (intake control valve), 32... Valve shaft, 34... Arm,
36... Leaf spring, 36a... Cylindrical end of the leaf spring, 38... Drive member, 48... Ball joint, 50... Bearing insert, 58... Skirt portion, 60... Slot, 62... protrusion.

Claims (1)

[Claims for Utility Model Registration] One end of a leaf spring is fixed to a drive member that is translated in translation by an actuator, and the other end of the leaf spring is formed into a substantially cylindrical shape, with a skirt portion extending downward and a partially spherical shape. A synthetic resin bearing insert having a substantially bottomed cylindrical shape and having a support surface is fitted into the substantially cylindrical other end of the leaf spring, and a ball is provided on a rotary valve opening/closing arm connected to a valve shaft of a rotary valve. In a rotary valve drive device in which a joint is rotatably fitted to a support surface of the bearing insert, a radius for preventing the ball joint from coming off is provided at a transition portion from the partially spherical support surface of the bearing insert to the inner surface of the skirt portion. A rotary valve drive device characterized in that a directional projection is provided, and a predetermined clearance is provided in the vertical direction between the surface of the projection and the surface of a ball joint.