JPH0129342Y2 - - 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 degree of the rotary valve. However, since the structure is such that the ball joint is held only by a resin bearing insert, there is a risk that creep may occur in the bearing insert due to engine heat and repeated loads, reducing the tightening force of the bearing insert. Furthermore, since the bearing insert is not provided with a cover, there is a risk that dust, muddy water, etc. may enter the sliding part between the ball joint and the support surface of the bearing insert and interfere with the smooth operation of the sliding part. There is.

[Purpose of the invention] The present invention solves the above-mentioned problems of the rotary valve drive device proposed above, and makes it possible for the bearing insert to maintain sufficient holding force even when subjected to repeated loads and heat. It is an object of the present invention to provide a rotary valve drive device that can effectively prevent dust and the like from entering the sliding portion.

[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 partially spherical support surface, and has a lower skirt portion. A substantially bottomed cylindrical synthetic resin bearing insert is fitted into the substantially cylindrical other end of the leaf spring, and a ball joint provided on an opening/closing arm integrated with the valve shaft of the rotary valve is fitted into the bearing insert. In a rotary valve drive device which is slidably snapped onto a support surface, the lower end of the substantially cylindrical other end of the leaf spring projects downward from the lower end of the skirt portion of the bearing insert, and the outer circumferential surface of the skirt portion It is characterized in that a minute clearance is provided between the leaf spring and the inner circumferential surface of the other end of the substantially cylindrical leaf spring.

[Effect]

With this arrangement, the portion of the cylindrical end of the leaf spring that protrudes below the bearing insert skirt serves to guide the skirt, thereby preventing deformation of the bearing insert. Also, since the cylindrical end of the leaf spring extends downward from the skirt and surrounds the outer circumference of the skirt,
This prevents dust from entering the ball joint.

〔Example〕

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

FIG. 2 shows a case where the rotary valve drive device of the present invention is applied to an internal combustion engine. In Figure 2, 10
is the engine body, 12 is the cylinder, 14 is the intake valve, 1
Reference numeral 6 indicates an exhaust valve, 18 indicates an intake port, and 20 indicates an intake pipe.The negative pressure chamber 24 of the actuator 22 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. connected within. 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,
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, so the diaphragm 40 moves to the right,
Move the drive member 38 to the right (see Fig. 4),
Each intake control valve 30 is rotated to its maximum closed position. 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 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 lower 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 in order to drive the drive member 38 to the left, the intake control valve 30 is rotated by an angle θ (FIG. 4) and is fully opened. In this way, high charging efficiency can be obtained during engine high-speed, high-load operation.

As best seen in FIGS. 3 and 4, 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. 1, 3, and 4, one end of an arm 34 is caulked to the valve stem 32. As shown in FIG. 1, 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 FIGS. 1 and 5), and is prevented from rotating by a protrusion 52. The insert 50 has a partially spherical support surface 56 formed below a bottomed shaft hole 54 that functions as a grease reservoir, and a ball joint 48 is fitted into this support surface 56 (see FIG. 1). ).
A skirt portion 58 is formed at the lower portion of the bearing insert 50. As shown in FIG.
8 is provided with a slot 60 along a plane including the axis of the ball joint 48, so that when the ball joint 48 is press-fitted into the bearing insert 50, the skirt portion 58 expands to facilitate fitting. It's getting old.

As shown in FIG. 1, the lower end of the cylindrical end portion 36a is located at a distance D of approximately 1 mm from the lower end of the skirt portion 58.
There is a minute clearance C between the inner circumferential surface of the end portion 36a and the outer circumferential surface of the skirt portion 58.
is provided. Since the cylindrical end portion 36a surrounds the skirt portion 58 with a minute clearance C in this manner, the end portion 36a acts as a guide member for the skirt portion 58, and the skirt portion 58 is moved by the action of heat and repeated loads. Prevent creep. Also,
Since the lower end of the end portion 36a projects downward, dust and muddy water flying from the side are prevented from entering the sliding portion between the support surface 56 and the ball joint 48.

[Effect of idea]

As described above, according to the present invention, in a rotary valve drive device, creep of the bearing insert due to heat and repeated loads is prevented, and the intrusion of dust and the like is prevented. Therefore, the holding force of the bearing insert can be maintained over a long period of time, and smooth operation of the device can be ensured.

[Brief explanation of the drawing]

Figure 1 is an enlarged sectional view of Figure 4 in the direction of the - arrow;
The figure is a horizontal sectional view of a part of an internal combustion engine, showing the arrangement of the rotary valve drive device of the present invention, FIG. 3 is a plan view of the rotary valve drive device of the present invention, FIG. 4 is an explanatory view showing the operation, Figure 5 is a side view of the leaf spring. 22... Actuator, 30... Rotary valve, 32... Valve shaft, 34... Arm, 36... Leaf spring, 36a... Cylindrical end, 38... Drive member, 48... Ball joint, 50 ... Bearing insert, 58 ... Skirt part.

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 and has a partially spherical support surface and a lower skirt. A substantially bottomed cylindrical synthetic resin bearing insert having a bottom is fitted into the substantially cylindrical other end of the leaf spring, and a ball joint provided on an opening/closing arm integrated with the valve shaft of the rotary valve is inserted into the bearing insert. In a rotary valve drive device which is slidably snapped onto a support surface of an insert, the lower end of the other substantially cylindrical end of the leaf spring projects downwardly from the lower end of the skirt portion of the bearing insert, and A rotary valve drive device characterized in that a minute clearance is provided between an outer circumferential surface and an inner circumferential surface of the other end of a substantially cylindrical leaf spring.