JPH0681966A - Flow rate control valve - Google Patents

Abstract

PURPOSE:To provide a flow rate control valve which is designed to prevent dislocation of a retainer attached to the tip of the output shaft of a motor and a retainer attached to the terminal of a valve stem. CONSTITUTION:A retainer formed such that a plurality of leg parts are provided and externally bent lock parts 24a-24c are attached to the respective leg parts is attached to the tip of an output shaft. A plate-form retainer 23 engaged with the retainer 24 served to hold a coil spring therebetween is attached to the terminal of a valve stem 6. Opening parts 23a-23c into which the lock parts 24a-24c of the respective leg parts are insertable are formed in the plate-form retainer 23 in a state that the opening parts are situated eccentrically from the axis of a valve stem 6. Engaging recessed parts 25a-25c with which the lock parts 24a-24c, respectively, are engaged are formed in succession to the opening parts 23a-23c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow control valve having a motor-driven lift type valve body used for controlling the flow rate of fluid.

[0002]

2. Description of the Related Art Conventionally, for example, as an exhaust gas recirculation valve for recirculating exhaust gas of an internal combustion engine to an intake system, a device for moving a lift type valve body by a step motor to control the amount of exhaust gas passing through a passage in a valve housing. However, JP-A 1-2
It is proposed in Japanese Patent Publication No. 03646.

In this recirculation valve, the front portion of the step motor is fixed to the end portion of the valve housing, the valve shaft connected to the valve element in the valve housing projects into the motor housing, and the step motor has the rotor inside the rotor. An output shaft that is movable only in the axial direction via a screw portion is provided, a retainer is attached to the ends of the output shaft and the valve shaft, and the two retainers are connected while allowing some axial movement, and A coil spring for urging the valve element in the closing direction when the valve is closed is held between the retainers.

[0004]

However, in this conventional recirculation valve, the two retainers for holding the coil spring have the protrusions provided on one retainer in the locking holes provided on the other retainer. Since the structure is such that the two retainers are connected while allowing axial movement by simply inserting and twisting and rotating one, there is a problem that the two retainers are easily disconnected due to vibration during operation.

The present invention has been made to solve the above problems, and is a flow control valve capable of preventing the retainer attached to the tip of the output shaft of a motor and the retainer attached to the end of the valve shaft from coming off. The purpose is to provide.

[0006]

In order to achieve this object, a flow control valve of the present invention is provided with a lift type valve body having a valve shaft in a valve housing, and a screw portion is provided in a rotor. In a flow control valve in which a motor having an output shaft that moves in the axial direction is attached and the output shaft moves in the protruding direction to move the valve element in the closing direction via the valve shaft, a plurality of output shafts are provided at the tip of the output shaft. Retainers each having a leg portion and having an outwardly bent locking portion provided at the tip of each leg portion are attached to the end of the valve shaft for engaging the retainer and holding a coil spring therebetween. A flat plate retainer is attached, and the flat plate retainer is formed with an opening eccentrically from the axial center of the valve shaft into which the locking portion of each leg of the retainer can be inserted, and the locking portion is inserted into the opening. And rotate the retainer with respect to the flat retainer. In addition, when the output shaft and the valve shaft are moved in a direction in which the shaft centers are aligned with each other, an engaging concave portion with which each locking portion engages is provided in the flat plate retainer continuously with each opening. To do.

[0007]

[Operation / Effect] When the retainer and the flat plate retainer are engaged and assembled, with the coil springs arranged between the retainer and the flat plate retainer, the locking parts of the legs of the retainer are opened in the flat plate retainer. The retainer is rotated with respect to the plate retainer, and is moved in a direction in which the output shaft and the valve shaft are aligned with each other. Thereby, the locking portion of each leg of the retainer enters the engaging recess from each opening of the flat retainer, and the retainer and the flat retainer are movable to some extent in the direction of compressing the coil spring between them. In addition, they are engaged with the output shaft and the valve shaft being aligned with each other.

In this way, the retainer is rotated with respect to the flat plate-shaped retainer, and is moved in a direction in which the output shaft and the valve shaft are aligned with each other to engage and connect both retainers. Is securely held, and the connecting portions of both retainers can be prevented from coming off due to vibration or the like. Further, since the flat plate-shaped retainer is used, the processing is easy and the manufacturing cost can be reduced.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a step motor driven type exhaust gas recirculation valve device to which the present invention is applied.
Reference numeral 1 denotes a valve housing that serves as a valve body. An inlet port 2 is provided in the lower portion of the valve housing 1, an outlet port 3 is provided on the upper left side thereof, and a valve seat 4 is provided in the passage.
Further, the valve body 5 attached to the tip of the valve shaft 6 is disposed so as to be seated on the valve seat 4, and the valve shaft 6 penetrates upward through a valve bearing 9 provided at the upper end of the valve housing 1. . The valve bearing 9 is fixed on the valve housing 1 by the fixing plate 7 via the gasket 7a.

A step motor 10 is attached downward to the upper end of the valve housing 1 via a connecting cover 8 having a cooling water passage.

Motor housing 1 of step motor 10
A front cover 12 is attached to the front surface, that is, the lower side of 1, and the motor housing 11 is clamped and fixed on the valve housing 1 via the front cover 12 and the connecting cover 8.

A stator in which a four-phase exciting coil 13 is wound around a bobbin is fixed in the motor housing 11, and a rotor 14 is arranged inside the stator.

The rotor 14 has its upper portion supported by the motor housing 11 by the bearing 15, and the lower portion of the rotor 14 is supported by the front cover 12 via the bearing 16. A permanent magnet 17 is attached to the outer periphery of the rotor 14,
An internal thread is provided on the inner circumference of the.

An output shaft 18 having an external thread to be screwed with the internal thread is disposed inside the rotor 14, and the output shaft 18 is provided.
Is supported by a bearing portion 19 provided on the front cover 12 so as to be vertically slidable, and the tip of the output shaft 18 projects downward from the front cover 12, that is, inside the connection cover 8.

A substantially cup-shaped retainer 24 having three legs is attached to the tip (lower end) of the output shaft 18 in the connecting cover 8, and a coil spring 22 outputs between the retainer 24 and the front cover 12. The shaft 18 is provided so as to be urged downward (in the valve closing direction) by a spring force.

As shown in FIGS. 2 and 3, the retainer 24 has three legs formed at intervals of about 120 °, and the lower ends of the legs are bent outward at a substantially right angle to lock the retainer 24. Part 24
a, 24b and 24c are formed. As shown in FIG.
When the shaft center of the output shaft 18 is P1, the locking portion 24b,
The tip of 24c is located on the periphery of a circle with a radius R1 centered on P1, and the tip of the locking portion 24a has a larger radius R2.
Located on the periphery of the circle. Further, the inner ends of the three locking portions are located on the periphery of a circle having a small radius R3 centered on P1.

A flat plate-shaped retainer 23 is attached to the tip (lower end) of the retainer 24 via a valve closing coil spring 21.
The upper end of the valve shaft 6 is fixed to the plate-like retainer 23 so as to be movable within a certain range.

As shown in FIGS. 4 and 5, the flat plate-shaped retainer 23 has three locking portions 2 of the retainer 24 in the disk.
Openings 23a for inserting 4a, 24b, 24c,
It is formed by providing 23b and 23c. The center position of the flat retainer 23 is P0, and the center P of the retainer 24 is P.
1 is aligned with the center P0 of the flat retainer 23, the locking portions 24a, 24b, 24c have openings 23a, 23, respectively.
The positions of the openings are set so that the openings can be inserted into b and 23c. As shown in FIG. 5, the valve shaft 6 having the axis P2
Is fixed at a position eccentric from the center P0 of the retainer 23 by a certain distance.

Further, each opening 23a, 23b, 23c
, The locking portions 24a, 24b, 24c are inserted into the openings to rotate the retainer 24 with respect to the flat plate retainer 23.
Further, when the shaft center P1 of the output shaft 18 and the shaft center P2 of the valve shaft 6 are moved in the same direction, the respective locking portions 24a, 24b, 2
Engagement recesses 25a, 25b, 25c with which 4c engages are provided continuously with each opening.

That is, the engaging recess 2 which is provided continuously to the opening 23a.
The outer peripheral edge of 5a is located on the circumference of a circle of radius R4 (the length between R1 and R3) centered at P0, and the inner peripheral edge thereof is a circle of radius R3 centered at the axis P2. Located on the circumference of. In addition, an engaging recess 25b that is continuously provided to the opening locking portion 23b
Is located on the circumference of a circle of radius R4 (length between R1 and R3) centered on the axis P2, and its inner peripheral edge is of a circle of radius R3 centered on P0. Located on the circumference.
Further, the outer peripheral edge of the engaging recess 25c that is provided continuously to the opening 23c is located on the circumference of a circle having a radius R4 (the length between R1 and R3) centered on the axis P2, and Peripheral part is P0
Is located on the circumference of a circle having a radius R3 centered at.

Also, the inner peripheral edge of the engaging recess 25a and 25
A small protrusion for locking the locking portions 24a and 24b when the retainer 24 is moved from the center P0 position to the shaft center P2 position is provided on the outer peripheral edge of b.

The coil closing coil spring 21 has a smaller winding diameter than the coil spring 22, and when the step motor 10 causes the output shaft 18 to project to the closing position, the valve body 5 causes the valve closing coil to close. The closed state is maintained by the total spring force of the spring 21 and the coil spring 21.

When the retainer 24 and the flat plate retainer 23 are engaged and assembled, first, with the coil spring 21 disposed between the retainer 24 and the flat plate retainer 23, as shown in FIG.
As shown in FIG.
24c is each opening 23a-23c of the flat retainer 23.
To insert.

Next, as shown in FIG. 7, the retainer 24 is rotated with respect to the flat plate retainer 23 in the counterclockwise direction in the figure, so that the locking portions 24a to 24c are engaged with the engaging recesses 25a to 25 from the opening.
Enter the c side. In this state, as shown in FIG. 8, the retainer 24 is further moved with respect to the flat plate-shaped retainer 23 in a direction in which the output shaft 18 and the valve shaft 6 are aligned with each other.

As a result, the engaging portions 24a to 24c of the legs of the retainer 24 are engaged with the engaging recess 25 of the flat retainer 23.
The retainer 24 and the flat plate-like retainer 23 are engaged with the output shaft 18 and the valve shaft 6 so that the coil spring 21 is compressed between the retainer 24 and the flat plate retainer 23 to some extent. .

In this way, the retainer 24 is rotated with respect to the flat plate-like retainer 23, and is moved in a direction in which the shaft centers of the output shaft 18 and the valve shaft 6 are aligned with each other, so that the retainers 23, 24 are engaged and connected. To ensure that their engagement is retained,
It is possible to prevent the connecting portion of the retainers 23 and 24 from coming off due to vibration or the like. Further, since the plate-shaped retainer 23 is used, the processing is easy and the manufacturing cost can be reduced.

The exhaust gas recirculation valve having such a structure is
It is used by connecting its inlet port 2 to the exhaust system of the internal combustion engine, connecting its outlet port 3 to the intake system, and further connecting the step motor 10 to its drive circuit. The drive circuit is controlled by a controller that totally controls the internal combustion engine according to its operating condition, and the forward / reverse rotation speed of the step motor is accurately drive-controlled thereby.

When the valve is opened from the valve closed state shown in FIG. 1, the step motor 10 rotates the rotor 14 in the direction in which the output shaft 18 is pulled back to raise the output shaft 18. At this time,
Although the coil spring 22 is compressed and the retainer 24 rises,
When the spring force of the coil spring 21 for closing the valve starts opening the valve (the valve body 5
Is still closed), the step motor 10 opens the valve with a small torque.

When the output shaft 18 further rises, the output shaft 1
8 rises only against the biasing force of the coil spring 22, and the spring force of the coil spring 22 is relatively small.
The step motor 10 operates with a small torque, and the valve element 5 moves in the opening direction.

On the other hand, when the valve is closed, the step motor 10 rotates the rotor 14 in the direction in which the output shaft 18 of the step motor 10 is projected, and lowers the output shaft 18. At this time, since the spring force of the coil spring 22 is applied in the downward direction of the shaft, the step motor 10 can be driven with a small torque. And the valve body 5
When it hits the valve seat 4, the output shaft 18 turns the coil spring 2 for closing the valve.
1 is compressed and lowered, and the step motor 10 is stopped.
In this state, the valve body 5 is biased and closed by the total spring force of the valve closing coil spring 21 and the coil spring 22, and is closed in a good sealed state.

Although the step motor is used in the above embodiment, a DC motor, an ultrasonic motor or the like may be used.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a flow control valve showing an embodiment of the present invention.

FIG. 2 is a front view of a retainer 24.

FIG. 3 is a bottom view of the retainer 24.

FIG. 4 is a front view of a flat retainer 23.

FIG. 5 is a plan view of a flat retainer 23.

FIG. 6 is a bottom view when the retainer 24 is connected to the flat plate retainer 23.

FIG. 7 is a bottom view when the retainer 24 is connected to the flat plate retainer 23.

FIG. 8 is a bottom view of the retainer 24 connected to the flat plate retainer 23.

[Explanation of symbols]

 1-Valve Housing, 5-Valve Disc, 6-Valve Shaft, 10-Step Motor (Motor), 14-Rotor, 18-Output Shaft, 21-Valve Closing Coil Spring, 23-Plate Retainer, 23a-23c- Opening part, 24-retainer 24a-24c-locking part, 25a-25c-engagement concave part.

Claims (1)

[Claims] 1. A lift type valve body having a valve shaft is provided in a valve housing, and a motor having an output shaft that moves axially via a screw portion is mounted in a rotor, and the output shaft is in a protruding direction. A flow control valve that moves a valve body in a closing direction via a valve shaft by moving, and has a plurality of legs at a tip of the output shaft, and an engaging portion bent outward at a tip of the leg. Is attached to the distal end of the valve shaft, and a flat plate-like retainer for holding the coil spring between the retainer and the retainer is attached to the distal end of the valve shaft. An opening into which the locking portion of the leg can be inserted is formed eccentrically from the axis of the valve shaft, and the locking portion is inserted into the opening to rotate the retainer with respect to the flat plate-shaped retainer, and the output shaft Was moved in the direction to match the axis of the valve shaft with Flow control valve, wherein the engaging recess respective locking portion is engaged is provided continuously with the respective openings in tabular retainer.