JP2002286150A - Flow control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow control valve capable of accurately setting the valve opening position without making a position adjustment using shim when installation is to be made at manufacturing and of decreasing the manufacturing costs. SOLUTION: A motor 20 is fixed onto a valve housing 1, and a straight moving member 25 of the output part of the motor 20 is positioned capable of being fitted in a pressing member 13, and a first valve element 10 equipped with a retaining pipe 10a is fitted on the lower part of a valve stem 12 from below the valve housing 1. A second valve element 11 is fitted at the bottom of the valve stem 12 into the bottom of the retaining pipe 10a, and the straight moving member 25 is contacted with the pressing member 13 by the operation of the motor 20 in the valve opening direction to cause a sink to the starting position of valve opening. In this condition, the contacting parts of the second valve element 11, retaining pipe 10a, and valve stem 12 are coupled fast together while confirmation is made that the first valve element 10 and second valve element 11 are closed.

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 which is used in an exhaust gas recirculation control device of an internal combustion engine or the like and has two lift-type valve bodies which are moved in an axial direction by a motor.

[0002]

2. Description of the Related Art Conventionally, as a flow control valve used for an exhaust gas recirculation control device of an internal combustion engine, for example, a flow control valve provided with two lift-type valve bodies which are moved in an axial direction by a motor is known. I have. In this flow control valve, as shown in FIG. 4, a first valve chamber 42 is formed at an upper portion in a valve housing 41, and a second valve chamber 42 is provided below the first valve chamber 42 through a first flow hole 44. 43 is formed, and a third valve chamber 46 is formed below the second valve chamber 43 via a second flow hole 45.

Further, an inlet / outlet port 47 is provided on both sides of the first valve chamber 42, an inlet port 48 is provided in the second valve chamber 43, and an outlet port 49 is provided in the third valve chamber 46.
Lift-type first valve element 5 so as to open and close first flow hole 44
0 is disposed so as to be seated on the valve seat portion of the first communication hole 44, and similarly, a lift-type second valve body 51 is provided on the valve seat portion of the second communication hole 45 so as to open and close the second communication hole 45. It is arranged so that it can be seated.

[0004] The two lift-type first and second valve bodies 50 and 51 are fixed at fixed positions on a valve shaft 52 vertically slidably supported by bearings 55. A pressing member 53 also serving as a cup-shaped spring holding member is attached to the coil spring 5 between the pressing member 53 and the valve housing 41.
4 is mounted so as to urge the valve shaft 52 in the valve closing direction (upward). To move the valve shaft 52 in the axial direction to open and close the valve, the motor 30 is driven by the valve housing 41.
Fixed on top.

[0005] The motor 30 comprises a motor housing 31.
A resin rotor magnet (a plurality of pole permanent magnets) is provided inside insulating resin coil bobbins 58 and 59 around which field windings (field coils) 56 and 57 provided around the inside are wound.
A rotor shaft 32 having an outer periphery provided with a bearing 3
6 so as to be rotatable. A screw is formed on the outer periphery of the tip of the rotor shaft 32, and a linear moving member 35 having a female screw is screwed to the external thread of the rotor shaft 32 so as to be able to move in the axial direction while preventing rotation. Thus, the linear moving member 35 is moved in the axial direction (vertical direction in the figure). The linear moving member 35 has its lower part in contact with the cup-shaped pressing member 53, resists the urging force of the coil spring 54, and opens and closes the valve via the pressing member 53.

[0006]

By the way, this kind of 2
When assembling at the time of manufacturing a flow control valve provided with a plurality of valve bodies, first, the first valve body 50 is press-fitted to a predetermined position on the valve shaft 52, and the valve shaft 52 is inserted into the bearing 55. In this state, a cup-shaped pressing member 53 is fixed to the upper end of the valve shaft 52 by screwing or the like, and a coil spring 54 is mounted between the pressing member 53 and the valve housing 41.

Next, the motor 30 is fixed on the valve housing 41, and the linear moving member 35 on the motor 30 side is brought into contact with and fitted to the cup-shaped pressing member 53. Due to the dimensional tolerance of the fitting position of the body 50, the fitting position of the linear moving member 35 and the pressing member 53 may vary from product to product. Therefore, the valve opening start position of the motor 30 is
A case occurs in which the actual valve opening start positions of the first valve body 50 and the second valve body 51 do not match.

For this reason, conventionally, the first valve body 50 and the second valve body 5 are operated while the motor 30 is operated to the valve opening start position.
1 is actually in the valve opening start state, that is, so that the linear moving member 35 starts contact with the pressing member 53,
The position of the motor 30 with respect to the valve housing 41 has been adjusted by inserting shims S of various thicknesses between the valve housing 41 and the motor housing 31. However, there is a problem that the adjustment by the shim requires man-hours and work time, and increases the manufacturing cost.

The present invention has been made in view of the above points, and can accurately set a valve opening position without performing position adjustment using shims at the time of assembly during manufacturing.
An object of the present invention is to provide a flow control valve capable of reducing manufacturing costs.

[0010]

In order to achieve the above object, a flow control valve according to the present invention comprises a valve shaft held slidably in an axial direction in a valve housing, and a flow control valve on the valve shaft. A first valve body axially mounted, a second valve body axially mounted on a valve shaft at a position away from the first valve body, a pressing member attached to an upper end of the valve shaft, a pressing member and a valve housing A coil spring interposed between the coil spring to axially urge the valve shaft, a motor fixed on the valve housing, and a linear moving member mounted on the output portion of the motor so as to be linearly movable and abutting on the pressing member. In the flow control valve, the holding pipe is vertically fitted in a central hole provided in the first valve body, the valve shaft is inserted into the holding pipe, and the first valve body is mounted on the valve shaft. The second valve body is mounted at a predetermined position between the holding pipe and the valve shaft, and the contact portion between the second valve body, the holding pipe, and the valve shaft is Wherein the mutually coupled and fixed.

Here, the contact portions of the second valve body, the holding pipe, and the valve shaft can be mutually connected and fixed by welding.

The first valve body is disposed so as to be able to be seated on a valve seat provided on a peripheral edge of a first communication hole between the first valve chamber and the second valve chamber provided in the valve housing, The second valve body can be configured so as to be seated on a valve seat provided on the periphery of the second communication hole between the second valve body and the third valve chamber provided below the second valve chamber.

[0013]

In order to assemble the flow control valve having the above construction at the time of manufacture, first, a valve shaft having a pressing member mounted on an upper portion thereof is mounted on a bearing in the valve housing from above with a coil spring mounted on the valve housing. The valve spring is inserted and mounted between the cup-shaped pressing member and the valve housing by urging the valve shaft upward.

Next, the motor is mounted and fixed on the valve housing, and the linear moving member of the motor is positioned so as to be able to be fitted into the pressing member. Next, the first valve body with the holding pipe is moved to the valve housing. The lower part of the valve shaft is fitted to the lower part of the valve shaft from below, the second valve body is fitted to the lower end of the valve shaft and the lower end of the holding pipe, and the motor is started in the valve opening direction to activate the linear moving member. The valve is brought into contact with the pressing member and lowered to the start position of the valve opening. In this state, the portions where the second valve body, the holding pipe, and the valve shaft are in contact with each other are connected and fixed while confirming that the first valve body and the second valve body are each closed. As a result, the valve opening start operation position of the motor is set to match the actual valve opening start state (valve closed state) of the first valve body and the second valve body. Therefore, an adjustment operation using a shim as in the related art becomes unnecessary, and man-hours and work time for the adjustment can be reduced.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a flow control valve used in an exhaust gas recirculation control device of an internal combustion engine.
In this flow control valve, a first valve chamber 2 is formed at an upper portion in a valve housing 1, and a second valve chamber 3 is formed below a first valve chamber 2 through a first communication hole 4. A third valve chamber 6 is formed below the two valve chambers 3 via a second flow hole 5.

Further, an inlet / outlet port 7 is provided on both sides of the first valve chamber 2, an inlet port 8 is provided on the left side of the second valve chamber 3, and an inlet port 8 is provided on the right side of the lowermost third valve chamber 6. An outlet port 9 is provided. A valve seat portion is provided around the first communication hole 4, and a lift-type first valve body 10 is disposed so as to be seated on the valve seat portion so as to open and close the valve seat portion. Similarly, a valve seat 16 is fitted around the second flow hole 5, and a lift-type second valve body 11 is disposed so as to be seated on the valve seat 16 so as to open and close the valve seat 16.

A center hole is formed in the first valve body 10,
The holding pipe 10a is vertically fixed to the lower part of the center of the first valve body 10 so as to be fitted in the center hole. The holding pipe 10a is formed so as to be able to be inserted into an outer peripheral portion of a valve shaft 12 described later, and its length is such that when the first valve body 10 is arranged at a fixed position of the valve shaft 12, the lower end of the holding pipe 10a is closed. It is set so as to reach a substantially lower end position of the shaft 12. On the other hand, the second valve body 11 has a central hole that can be fitted to the lower end of the holding pipe 10a, and is fitted to the lower end of the holding pipe 10a that is fitted to the lower end of the valve shaft 12 during assembly, as described later. And welded.

The valve shaft 12 is vertically slidably supported by a bearing 15 provided in the center of the valve housing 1. The first valve body 10 and the second valve body 11 allow the first flow passage when the valve shaft 12 rises. The valve shaft 12 is fixed at a fixed position below the valve shaft 12 so as to close the hole 4 and the second flow hole 5. A cup-shaped pressing member 13 is attached to an upper end of the valve shaft 12, and a coil spring 14 is mounted between the pressing member 13 and the valve housing 1 so as to urge the valve shaft 12 in a valve closing direction (upward). . A motor (step motor) 20 is fixed on the valve housing 1 to move the valve shaft 12 in the axial direction to open and close the valve.

The motor 10 comprises insulating resin coil bobbins 23a, 23b having field windings (field coils) 22a, 22b provided in a motor housing 21 wound around the outer periphery thereof.
, A rotor shaft 28 having a resin-made rotor magnet (a plurality of permanent magnets) 24 provided on an outer peripheral portion thereof is rotatably arranged via bearings 26 and 27.

A screw is formed on the outer periphery of the tip end of the rotor shaft 28, and a linear moving member 25 having a female screw is screwed to the external thread of the rotor shaft 28 so as to prevent rotation and move in the axial direction. Is a structure for moving the linear moving member 25 in the axial direction (vertical direction in the figure) by the rotation of. The lower portion of the linear moving member 25 abuts inside the pressing member 13, resists the urging force of the coil spring 14, and opens and closes the valve via the pressing member 13. on the other hand,
A lid 29 for closing the third valve chamber 6 from below is fitted to a lower portion of the valve housing 1.

The flow control valve having the above structure is assembled and manufactured as follows at the time of its manufacture. That is, FIG.
As shown in (1), first, a bearing 15 is assembled at the center of the upper part in the valve housing 1 (a). Next, with the coil spring 14 placed in the upper concave portion of the valve housing 1 (at a position above the bearing 15), the valve shaft 1 with the pressing member 13 mounted thereon is mounted.
2 is inserted into the bearing 15 from above and mounted (b). At this time, the coil spring 14 is mounted between the cup-shaped pressing member 13 and the valve housing 1 by urging the valve shaft 12 upward.

Next, a motor 20 is provided above the valve housing 1.
And fix it by tightening the fixing bolt. At this time, the linear moving member 25 of the motor 20 (located at the valve closing position at the retracted end) is in a state of being fitted into the pressing member 13 (c). Next, the first valve body 10 with the holding pipe 10a
Is fitted onto the lower part of the valve shaft 12 from below the valve housing 1, and then the valve seat 16 is fitted around the second flow hole 5 (d).

Then, the second valve body 11 is fitted to the lower end of the valve shaft 12 and the lower end of the holding pipe 10a.
Is started in the valve opening direction (in the case of a step motor, it is driven by a predetermined step) and the linear moving member 25 is pressed by the pressing member 13.
And lowered to the start position of the valve opening. In this state, while confirming that the first valve body 10 and the second valve body 11 are in contact with the respective valve seats, the lower end portion where the second valve body 11, the holding pipe 10a, and the valve shaft 12 abut. Are welded together to join them together.

Thus, the valve opening start operation position of the motor 20 is set to coincide with the actual valve opening start state (valve closed state) of the first valve body 10 and the second valve body 11. Then, a lid 29 is fitted to the lower side of the third valve chamber 6 in the valve housing,
The lower part of the valve housing 1 is closed.

As described above, the motor 20 is operated to the valve opening start operation position (the position where the linear moving member 25 contacts the pressing member 13), and the first valve body 10 and the second valve body 11 are closed. , Second valve body, holding pipe 10a, and valve shaft 1
If the lower ends of the second 2 are welded and fixed to each other at that position, the valve opening start position of the motor 20 matches the actual valve opening start state (valve closing position) of the first valve body 10 and the second valve body 11. Therefore, unlike the related art, there is no need to adjust the position of the motor 20 with respect to the valve housing 1 by shim adjustment, and the number of adjustment steps and work time can be reduced.

As shown in FIG. 1, the flow control valve having the above construction is mounted so as to be inserted into a part of an intake pipe 17 of an internal combustion engine, and an exhaust port is provided at an inlet port 8 thereof. The outlet pipe 9 is connected to a reflux pipe 18, and a connection pipe 19 is connected to the outlet port 9.
It is communicated and connected to the downstream side of the intake pipe 17.

The motor 20 is connected to a controller (not shown), and the controller calculates an optimum EGR rate based on detected values such as the rotation speed of the internal combustion engine and the amount of intake air.
The first valve body 10 and the second valve body 11 are lowered and opened so as to rotate the motor 20 in accordance with the R rate and obtain the exhaust gas recirculation amount in accordance with the EGR rate, as shown in FIG. The exhaust gas sent from the exhaust gas recirculation pipe 18 is recirculated to the intake pipe 17 from the inlet / outlet port 7 of the first valve chamber 2 through the first circulation hole 4,
The gas is recirculated from the third valve chamber 6 through the second flow hole 5 to the outlet pipe 9 and the intake pipe 17 through the connection pipe 19.

Exhaust gas recirculated from the exhaust gas recirculation pipe 18 enters the second valve chamber 3 from the inlet port 8, and the exhaust pressure is applied to the first valve body 10 and the second valve body 11 in opposite directions. Since exhaust pressure is applied to the body 10 in the valve closing direction and the second valve body 11 is opened in the valve opening direction, the influence of the exhaust pressure on the first valve body 10 and the second valve body 11 that move at the same time hardly occurs. 2
A value of 0 controls the opening and closing of the valve with a small driving force, so that the amount of exhaust gas recirculation can be controlled smoothly.

[0029]

As described above, according to the flow control valve of the present invention, the second valve body, the holding pipe, and the valve shaft which are closed when the motor is operated to the valve opening start position. Are configured to be connected and fixed to each other, so that the valve opening start position of the motor matches the actual valve opening start state (valve closing position) of the first and second valve bodies. In addition, unlike the related art, there is no need to adjust the position of the motor with respect to the valve housing by shim adjustment, so that the number of adjustment steps and work time can be reduced, and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a flow control valve showing one embodiment of the present invention.

FIG. 2 is a cross-sectional view of the flow control valve in an open state.

FIG. 3 is an explanatory sectional view showing a process of assembling a flow control valve.

FIG. 4 is a sectional view of a conventional flow control valve.

[Explanation of symbols]

 1-Valve housing 10-First valve body 10a-Holding pipe 11-Second valve body 12-Valve shaft 13-Pressing member 14-Coil spring 20-Motor 25-Linear moving member

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference)

Claims (3)

[Claims] 1. A valve stem slidably held in an axial direction within a valve housing, a first valve body mounted on the valve shaft, and a position separated from the first valve body. A second valve body axially mounted on the valve shaft, a pressing member attached to the upper end of the valve shaft,
A coil spring interposed between the pressing member and the valve housing for urging the valve shaft in the axial direction, a motor fixed on the valve housing, and linearly mounted on an output portion of the motor; And a linear moving member abutting on the pressing member, wherein a holding pipe is vertically fitted into a central hole provided in the first valve body, and the valve shaft is inserted into the holding pipe. The first valve body is fitted to the valve shaft, and the second valve body is mounted at a predetermined position on the holding pipe and the valve shaft. The second valve body, the holding pipe, and the valve A flow control valve characterized in that the contact portions of the shafts are connected and fixed to each other. 2. The flow control valve according to claim 1, wherein the contact portions of the second valve body, the holding pipe, and the valve shaft are mutually connected and fixed by welding. 3. The valve body according to claim 1, wherein the first valve body is seated on a valve seat provided at a periphery of a first communication hole between the first valve chamber and the second valve chamber provided in the valve housing. The second valve body is disposed so as to be able to be seated on a valve seat provided on a peripheral edge of a second communication hole between the second valve body and a third valve chamber provided below the second valve chamber. Flow control valve.