JPH06167226A - Butterfly valve - Google Patents

Abstract

PURPOSE:To reduce driving torque which is required for closing a valve and to reduce a size in a control motor. CONSTITUTION:A butterfly valve opens/closes an intake passage 2 of an engine on the basis of the control by a control motor 15, and is usually energized toward the open direction by a return spring 14. A shaft center C2 of a valve shaft 11 is offset to a bore center C1 of the intake passage 2, and a valve body 10 is provided in the valve shaft 11 so that an open/close end 10a, which is farther from the shaft center C2 than an open/close end 10b, is positioned on the upperstream side than the open/close end 10b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butterfly valve which opens and closes an intake passage of an automobile engine mainly by controlling a control motor.

[0002]

2. Description of the Related Art First, an example of a throttle valve control device incorporating a butterfly valve of this type will be described with reference to FIG. The throttle valve control device of this example is a traction control (also referred to as TRC) throttle body. In FIG. 1, a main body 3 arranged in an intake system of the engine has a main valve 3 for adjusting an intake amount of the engine by opening and closing an intake passage 2.
Main valve system mainly consisting of
A sub-valve system mainly including the RC sub-valve 4 is arranged. Both valves 3 and 4 are butterfly valves.

In the main valve 3, both ends of a valve shaft 6 to which the valve body 5 is fixed are rotatably supported by the body body 1. A throttle lever 7 is attached to one end of the valve shaft 6 on the right side in the drawing. Throttle lever 7 has
A tip end portion of an accelerator wire linked to an accelerator pedal on the floor of a driver's seat of a vehicle (not shown) is connected. Further, a return spring 8 is arranged between the throttle lever 7 and the body 1 to urge the main valve 3 in the closing direction and always keep the main valve 3 at the fully closed position. A main throttle sensor 9 is provided on the left side surface of the body 1 in the figure. The throttle sensor 9 detects the opening of the main valve 3 from the amount of rotation of the valve shaft 6 and inputs the detection signal to a control circuit composed of an electronic control unit (also referred to as an ECU) (not shown).

In the sub-valve 4, both ends of the valve shaft 11 to which the valve body 10 is fixed are rotatably supported by the body body 1. A sub-throttle sensor 12 is provided on the right side surface of the body 1 in the figure. The throttle sensor 12 detects the opening degree of the sub-valve 4 from the rotation amount of the valve shaft 11 and inputs the detection signal to the control circuit. A throttle sensor lever 1 that engages with a detector of a sub-throttle sensor 12 is provided at the right end of the valve shaft 11 in the figure.
3 is attached. Throttle sensor lever 1
A return spring 1 for urging the sub-valve 4 in the opening direction and always holding it in the fully open position between the body 3 and the body 1.
4 are arranged.

A control motor 15 consisting of a step motor is provided on the left side surface of the body 1 in the figure. The output shaft (reference numeral omitted) of the control motor 15 and the valve shaft 11 of the sub-valve 4 are connected via a reduction gear transmission mechanism 16. The control motor 15 controls opening / closing of the sub-valve 4 according to a control signal transmitted from the control circuit. The above-mentioned TRC throttle body is, for example, an “internal combustion engine (VO
L.28 / NUMBER352 "(Sankaido Co., Ltd., published in February 1989)
54 to 56, "Technical Description: Throttle Body for Traction Control".

The sub-valve 4 opens and closes the intake passage 2 of the engine under the control of the control motor 15 and is always urged in the opening direction by the return spring 14, and corresponds to the butterfly valve targeted by the present invention. is doing. This sub-valve 4 is conventionally set such that the axis C ₂ of its valve shaft 11 is located on the bore center C ₁ of the intake passage 2 as shown in the explanatory view of FIG. The body 10 is provided such that the lengths from the axis C ₂ to the open / close ends 10a and 10b are equal to each other. Note that in FIG. 2, the fully open state of the sub valve 4 is shown by a solid line, and the fully closed state thereof is shown by a chain double-dashed line.

[0007]

In the conventional sub valve 4, the control motor 15 must be driven with a driving torque that overcomes the biasing torque of the return spring 14. Therefore, the driving torque required for closing the valve is large, so that the control motor 15 becomes large.

Therefore, the present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a butterfly valve capable of reducing the drive torque required for closing the valve and downsizing the control motor. To provide.

[0009]

SUMMARY OF THE INVENTION A butterfly valve according to the present invention for solving the above-mentioned problems is a butterfly valve in which an intake passage of an engine is opened / closed under the control of a control motor and is always urged in an opening direction by a return spring. , The axis of the valve shaft is offset with respect to the center of the bore of the intake passage, and the valve shaft is provided such that the valve body located farther from the shaft center is located upstream of the closer open / close end. Has been.

[0010]

According to the above means, the intake shaft negative pressure acts on the valve body in the valve closing direction more than in the valve opening direction by arranging the valve shaft offset with respect to the center of the bore of the intake passage.
Valve closing torque is generated due to the negative pressure in the intake pipe. Therefore, the drive torque of the control motor required for closing the valve can be small.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. Since this example is carried out in the sub-valve 4 of the throttle valve control device described in the conventional example, the modified parts relating to the implementation will be described in detail, and the parts which are considered to have the same or equivalent configuration as the conventional example are shown in the drawings. Are denoted by the same reference numerals and redundant description will be omitted. The sub-valve 4 is arranged as follows with respect to the bore center C ₁ of the intake passage 2 as shown in the explanatory view of FIG. 1 in addition to FIG. The valve shaft 11 is
The axis C ₂ is offset with a dimension A from the bore center C ₁ of the intake passage 2. Therefore, the valve body 10
Is the opening / closing end 10 on the side farther from the axis C _{2 of the} valve shaft 11.
It is attached so that a is located upstream of the closer opening / closing end 10b.

According to the sub-valve 4, the half of the opening / closing end 10a of the valve body 10 on the side of the valve shaft 11 is the opening / closing end 10 thereof.
It has a larger area than the b-side half and receives a large amount of negative pressure in the intake pipe. Therefore, the intake pipe negative pressure acts in the valve closing direction of the valve body 10 (the clockwise direction in FIG. 3), and the valve closing torque is generated by the intake pipe negative pressure. Since this valve closing torque cancels out a part of the urging force of the return spring 14, the drive torque (also referred to as motor torque) of the control motor 15 required for closing the valve can be small.

The difference between the embodiment and the conventional example will be described in detail with reference to the characteristic diagram of FIG. The right side of the drawing shows the example, and the left side shows the conventional example. The same return spring 1 for each example
4 shall be used. In each of the examples, the torque of the return spring 14 that acts on the valve opening side increases proportionally as the opening degree of the sub valve 4 moves from the open direction to the closed direction, as indicated by the thin line.

In the conventional example, the motor torque required for the control motor 15 is set to a magnitude obtained by adding a margin torque to the maximum value of the torque of the return spring 14 as shown by a solid line. Further, in the embodiment, the sub valve 4
Due to the negative pressure of the intake pipe, a valve closing torque whose opening degree increases in the negative direction in proportion to the opening to the closing direction is exerted as indicated by a two-dot chain line. Therefore, the torque acting on the valve opening side has a magnitude obtained by subtracting the valve closing torque from the torque of the return spring 14 as shown by the dotted line.

From this, the motor torque required for the control motor 15 of the embodiment is the magnitude of the maximum value of the torque of the return spring 14 plus the margin torque (the same torque as the conventional example) as shown by the solid line. Is set to a lower torque than the conventional example. Therefore, according to the embodiment, since the motor torque of the control motor 15 required for closing the valve is small, it is possible to use the control motor 15 which is smaller than the conventional one.

[0016]

According to the butterfly valve of the present invention, since the valve closing torque due to the negative pressure of the intake pipe acts on the valve body, the driving torque of the control motor required for closing the valve can be reduced, and a small control motor can be used. Is possible.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example.

FIG. 2 is an explanatory diagram showing a conventional example.

FIG. 3 is a cross-sectional view showing an example of a throttle valve control device.

FIG. 4 is a characteristic diagram showing the relationship between valve opening and motor torque.

[Explanation of symbols]

2 Intake passage 4 Sub valve 10 Valve bodies 10a, 10b Open / close end 11 Valve shaft C ₁ Bore center C ₂ Shaft center

Claims (1)

[Claims] 1. A butterfly valve in which an intake passage of an engine is opened / closed under the control of a control motor and is always urged in an opening direction by a return spring so that an axial center of a valve shaft with respect to a bore center of the intake passage. Offset
A butterfly valve in which a valve element is provided on the valve shaft so that an opening / closing end farther from the shaft center is located upstream of an opening / closing end closer to the shaft center.