JPH0610775A - Liquid control valve device - Google Patents

Abstract

PURPOSE:To finely control the opening degree of a valve element so as to optimumly adjust the flow rate of fluid flowing into a port. CONSTITUTION:A stopper (lift adjusting mechanism) 34 adapted to abut against a receiver (stop ring) 45 provided to a shaft part 20a of a valve element 20 for opening and closing a port 5, so as regulate the maximum lift of the valve element 20, is threadedly engaged with a cylindrical part 33 in the upper end part of a body 4 in which the valve element 20 is incorporated, the stopper 43 being rotated by a suitable actuator. With this arrangement, the opening degree of the valve element 20 can be simply and precisely controlled only by vertically replacing the stopper 34, irrespective of the pressure of fluid for driving the valve element 20. Thereby it is possible to optimize the value of fluid flowing into the port 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid control valve device such as an EGR valve mounted in an exhaust system of an internal combustion engine.

[0002]

2. Description of the Related Art An EGR valve recirculates a part of exhaust gas to an intake system to lower a combustion temperature in a cylinder,
It is known to suppress the generation of Ox, as shown in FIG.

That is, the conventional EGR valve shown in FIG.
(1) is installed vertically on a flange (2a) opened at the upper end of a bypass pipe (2) connected to the exhaust pipe of a multi-cylinder diesel engine, and its port outlet end is an inlet pipe.
It is connected to the engine intake pipe via (3).

The cast body (4) has an elbow-shaped recirculation port (5) with the exhaust gas inlet side facing downward and the outlet side facing sideways, and at each open end. The flanges 6 and 6 are integrally formed.

At the upper end of the body (4), a relatively large circular mounting seat (7) which acts as a heat shield plate and a heat radiating plate by extending horizontally to the side of the body (4) is provided. The mounting seat (7) is formed integrally with the intermediate part of (4) with a required distance.
Is reinforced by a plurality of thin plate-shaped ribs (8) extending downward from the lower surface thereof toward the middle portion of the body (4).

A plurality of protrusions (9) having a smooth upper surface are integrally formed on the upper surface of the mounting seat (7), and a plurality of through holes (10a) are provided near the center of each protrusion (9). , The spring seat (10) having approximately the same diameter as the mounting seat (7), and further on the upper surface of the spring seat (10),
The cylinder (11) with a top of the actuator (A) is integrated by screwing the bolts (12) toward the plurality of bosses (7a) on the upper surface of the outer peripheral portion of the mounting seat (7). Is stuck to.

As a result, the upper surface of the mounting seat (7) and the spring bearing are
A small gap (13) communicating with the outside air is formed between the lower surface of (10) and the lower surface.

Reference numeral (14) is a seal member having a small thermal conductivity, which is interposed between the spring bearing (10) and the cylinder (11).

Inside the cylinder (11), a cylindrical piston (15) having an upper surface closed, which is in close contact with a thick portion (11a) formed in the intermediate portion of the inner peripheral surface thereof, is vertically slidable. It has been inserted.

A pipe (16) for supplying air from a compressed air source (not shown) such as a compressor into the cylinder (11) is connected to the upper surface of the cylinder (11).

The space between the lower surface of the cylinder (11) and the upper surface of the piston (15) is a high pressure chamber (operating pressure chamber) (17a), and the space surrounded by the piston (15) is a low pressure chamber. It is a room (open to the atmosphere) (17b).

Reference numeral (18) is a compression coil spring compressed in the high pressure chamber (17a), and constantly pushes the piston (15) downward.

At the center of the body (4), the valve guide (1
9) is press-fitted, and its upper end portion penetrates the center of the spring bearing (10) and is located in the lower portion inside the piston (15).

The shaft portion (20a) of the mushroom-shaped valve body (20) is slidably fitted into the valve guide (19), and the shaft end portion located in the piston (15) is A pair of cotters (22) (22) in which the retainer (21) is externally fitted in the annular groove (20b) formed on the outer peripheral surface of the shaft portion in the tapered hole (21a) formed in the center thereof.
It is fixed by fitting in.

A valve spring (compression coil spring) (23) is compressed between the lower surface of the retainer (21) and the upper surface of the spring receiver (10).

As a result, the valve body (20) is always urged upward, and the umbrella portion (20c) is in close contact with the valve seat (24) fitted in the lower end opening of the return port (5) during normal operation. As a result, the return port (5) is closed.

In the normal state, the inner bottom surface of the piston (15) has a compression coil spring (18) compressed inside the high pressure chamber (17a).
By the biasing force of
When the valve is closed, the lower end of the piston (15) and the spring bearing (1
The required gap is formed between 0). This gap becomes the maximum lift amount of the valve body (20), that is, the opening / closing stroke.

When the engine is in a low load operation region and compressed air is pumped into the high pressure chamber (17a) by the operation of a control device (not shown), the piston (15) and the valve body (20) move to the valve spring ( It is pushed down integrally against 23) and stops when the lower end of the piston (15) comes into contact with the spring bearing (10).

As a result, the valve body (20) is opened, and the exhaust gas flowing into the bypass pipe (2) is sent into each cylinder of the engine through the recirculation port (5) and the introduction pipe (3). . As a result, the combustion state becomes slower, the combustion temperature is kept low, and the NOx emission amount is reduced.

When the engine enters the high load operation region, the control device works again to stop the supply of compressed air, so that the valve body (20) and the piston (15) move to the valve spring (23).
And the return port (5) is automatically closed.
As a result, exhaust gas recirculation is stopped, and output (torque) drop and smoke deterioration are prevented.

[0021]

In order to effectively reduce the NOx emission amount, it is desirable to optimally adjust the exhaust gas recirculation amount (EGR rate) in accordance with the engine load, rotational speed, etc. For that purpose, it is necessary to finely control the opening degree (lift amount) of the valve body (20).

However, the above-mentioned conventional EGR valve (1)
In the system in which the actuator (A) for driving the valve body (20) is actuated by compressed air (which may be a vacuum pressure), the valve body (20) is It is very difficult to finely control the opening degree of the valve according to the load of the engine, etc., and it is common to perform two-step control of ON (open) or OFF (closed).

That is, even if the air pressure supplied to the actuator (A) and the opening degree of the valve body (20) are preset so as to have a certain relationship, the compressed air accumulated in the air tank is When supplied to other auxiliary equipment such as an air brake and consumed, pressure fluctuations occur in the air tank, pulsation occurs in the pipeline, valve springs, etc.
When the set load and the spring constant of (23) are varied, the relationship is not established.

The high pressure chamber (17a) of the actuator (A)
Leak some of the compressed air supplied to the valve body (20)
It is also possible to finely control the opening of the valve body (20) according to the load of the engine by adjusting the pressure of the air to operate, but in this case, the consumption of compressed air increases, It is necessary to increase the size of the air compressor and to operate it frequently, which increases mechanical loss.

The present invention has been made to solve the above problems, and finely controls the opening of the valve regardless of the pressure of the working fluid, thereby optimally adjusting the flow rate of the fluid flowing into the port. It is an object of the present invention to provide a fluid control valve device that can be operated.

[0026]

In order to achieve the above object, the present invention has a port for fluid flow, and
For fluid control, including a body that accommodates a valve body that opens and closes a port by reciprocating, and valve driving means that is attached to the body and that opens and closes the valve body by driving a shaft portion of the valve body. In the valve device, at a proper position of the body, abutting a receiving portion that is substantially integrated with the shaft portion,
It is characterized in that a stopper for restricting the maximum lift amount of the valve element is provided so as to be movable in the axial direction of the valve element by linking it with an appropriate actuator.

[0027]

The stopper for regulating the maximum lift amount of the valve body by contacting the receiving portion which is integral with the shaft portion of the valve body is provided at a proper position of the body accommodating the valve body for opening and closing the port by an appropriate actuator. Since it is provided so as to be movable in the axial direction of the valve element, the opening degree of the valve element can be controlled easily and accurately regardless of the fluid pressure for driving the valve element simply by displacing the position of the stopper appropriately. be able to. Therefore, the amount of fluid flowing into the port is always optimal.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The same members and members having the same functions as those in the conventional example shown in FIG. 5 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In FIGS. 1 and 2, the actuator
The cylinder (11) in (A) has a spring bearing (31) on the upper surface of a plurality of ribs (30) which are continuously provided upwardly around the upper end of the body (4).
Also, the bolts (12) are fixed through the seal member (32).

The cylindrical portion (33) at the center of the body (4), into which the upper half of the valve guide (19) is press-fit, has a through hole (31a) formed at the upper end of the cylindrical portion (33) at the center of the spring receiver (31). Is located inside the cylinder (11) by penetrating therethrough, and a male screw (33a) is threaded on the upper half of the outer peripheral surface thereof.

The cylindrical portion (33) has a shaft portion of the valve body (20) at the upper end thereof.
(20a) is provided with an upward cylindrical stopper (34a) in sliding contact with the outer peripheral surface, and a lift adjusting cylinder (34) formed by forming a gear (34b) with a long tooth width on the outer peripheral surface of the lower half part, A female screw (34c) threaded on the inner peripheral surface is screwed onto the male screw (33a) so that the female screw (34c) is coaxially fitted with the axial center of the valve body (20) and is externally fitted so as to be movable in the axial direction. The male screw (33a) and female screw (34
c) is a left-hand thread, and is adapted to move upward when the lift adjusting cylinder (34) rotates clockwise in plan view.

The upper end portion of the body (4), that is, the cylindrical portion (33)
At the end of the horizontal support piece (35) extending outward from the lower end of the support tube (35a), a support tube (35a) is continuously provided so as to face upward. Support tube
On the upper surface of (35a), as shown in detail in FIG.
A sector gear (36) meshing with (34b) is rotatably supported in a horizontal direction by a pin (37) press-fitted into a support cylinder (35a).

Reference numeral (38) is a backlash preventing member such as synthetic resin having a small friction coefficient, which is prevented from coming off by the snap ring (39). A V-shaped groove (36b) is formed on the outer peripheral surface of the substantially semicircular substrate (36a) on the side opposite to the tooth row in the sector gear (36), and the drive wire (40) is formed in the V-shaped groove (36b). Is fitted with a cylindrical locking piece (41) fixed at its tip into a locking groove (42) formed in the outer peripheral end of the board (36a) opposite to the driving direction (counterclockwise in plan view). By doing so, the substrate (36a) is wound around almost half the circumference thereof.

Reference numeral (43) is a torsion coil spring externally fitted to the support cylinder (35a), one end of which is locked to the support cylinder (35a) and the other end of which is locked to a proper place on the lower surface of the sector gear (36). As a result, the sector gear (36) has its tooth row with one end side (driving direction side) of the lift adjustment cylinder (34) when the valve body (20) is fully closed.
It is constantly urged to return to a fixed position where it meshes with the gear (34b).

The annular groove (44) formed on the outer peripheral surface of the upper end of the shaft portion (20a) of the valve body (20) is brought into contact with the cylindrical stopper (34a) of the lift adjusting cylinder (34). A stop ring (45) for restricting the maximum lift amount of the valve body (20) is fitted.

The opening stroke of the valve body (20) depends on the sector gear.
(36) and the gear (34b) are in a meshed state as shown in FIG.
Maximum when the lift adjustment tube (34) is at the lower limit. In the above embodiment, the drive wire (40), for example, the control lever and accelerator of the fuel injection pump in the diesel engine, the load and rotation speed of the engine changes according to the displacement amount, through an appropriate auxiliary mechanism. Rotation of the sector gear (36) by mechanically connecting them or by electrically detecting their displacement and connecting them to an actuator (not shown) such as a step motor or electromagnetic solenoid that operates based on the signal. Control, the lift amount of the valve body (20) can be automatically and optimally adjusted according to the load and the rotation speed of the engine.

That is, for example, when the engine is in a high-speed and high-load operating region, the actuator and the like are driven
When the (40) is pulled, the sector gear (36) rotates counterclockwise in a plan view from the fixed position (home position) as shown in FIG. 2, so that the lift adjusting cylinder (34) meshing with the sector gear (36) rotates in a plan view time. When the cylindrical stopper (34a) and the stop ring (45) are rotated by moving in the direction, the relative distance between the cylindrical stopper (34a) and the stop ring (45) becomes smaller.

Therefore, even if the valve body (20) is opened by the compressed air supplied to the actuator (A), the lift amount is suppressed to be small and the exhaust gas recirculation amount (EGR rate) is reduced. This prevents output (torque) reduction and smoke deterioration.

On the other hand, when the engine reaches the operating range of medium-low speed and low load, the actuator gear or the like is reversely rotated to loosen the pulling force of the drive wire (40) and the sector gear (36) is twisted. Since the lift adjustment cylinder (34) is rotated counterclockwise in the opposite direction to the above by rotating it in the clockwise direction by the urging force of the coil spring (43), the lift adjustment cylinder (34) is moved to the cylindrical stopper (34a). The relative distance to the stop ring (45) becomes large.

As a result, the lift amount of the valve body (20) becomes large, the exhaust gas recirculation amount increases, and the NOx emission amount is suppressed. In this way, the actuator for driving the sector gear (36) or the like is controlled stepwise or steplessly according to the load of the engine, the rotation speed, etc., and if the lift amount of the valve body (20) is adjusted appropriately, The exhaust gas recirculation amount sent to the engine can always be optimized, and deterioration of output and smoke can be minimized and NOx can be effectively reduced.

Moreover, since the lift amount of the valve body (20) can be adjusted independently of the air pressure for actuating the actuator (A), the lift amount is affected even if the air pressure fluctuates as in the conventional case. And the waste of compressed air is prevented.

The present invention is not limited to the above embodiments, but can take various forms. For example, the male screw (33a) of the cylindrical part (33) and the female screw (34c) of the lift adjusting cylinder (34) may be two or more multi-threaded screws, or the lead angles of the threads may be different from each other. If you do this, the lift adjustment tube (3
The vertical movement amount and speed of 4) become large and the responsiveness becomes good, and it is possible to quickly respond to changes in the engine load and rotational speed.

As for the response, the gear ratio between the gear (34b) of the lift adjusting cylinder (34) and the sector gear (36) is increased, or the angular velocity is changed by an elliptical gear mechanism or the like.
It can also be increased by speeding up the rotation of the lift adjustment cylinder (34).

The cylindrical stopper (3) in the lift adjustment barrel (34)
The contact surfaces of 4a) and the stop ring (45) are molded or coated with a material having a small friction coefficient, such as a synthetic resin, to reduce the frictional resistance when they rotate while contacting each other. May be.

Further, as shown in FIG. 3, a cylindrical stopper (3
A thrust bearing (46) may be fitted on the upper end of 4a), and in this case, frictional resistance is significantly reduced.
In this case, the thrust bearing (46) is the stop ring.
It may be provided on the (45) side.

The lift adjusting cylinder (34) may be moved up and down by a cam plate instead of the screw type. That is, as schematically shown in FIG. 4, the lift adjustment cylinder (34) is fitted in the cylindrical portion (33) so as to be slidable in the vertical direction, and the upper surface of the support piece (35) is fixed to the cam surface (47a). ) Became a forked cam plate (47)
Is mounted so that the cylindrical part (33) is sandwiched, and the drive rod (48) connected to an appropriate actuator is advanced and retracted to move the cam plate.
By sliding (47) in the horizontal direction, the lift adjusting cylinder (34) mounted on the cam surface (47a) is moved up and down.

Also by this, the lift amount of the valve body (20) can be appropriately controlled according to the load of the engine.
When such a cam plate (47) is used, the compression coil spring (49) having a relatively small spring constant or the like constantly presses the lift adjustment cylinder (34) downward to move it against the cam surface (47a). It is good to keep trackability.

When driving the above-mentioned sector gear (36), a rod or a link may be used instead of the drive wire (40). Instead of fitting the stop ring (45),
An annular projection similar to this may be formed integrally with the shaft portion (20a), and without providing such a stop ring (45) or projection, the retainer (21) is used as a substitute for them. There are also things to do.

The present invention can be applied not only to the EGR valve (1) provided with the piston type actuator (A) but also to an EGR valve provided with a diaphragm type (vacuum type) actuator. It can also be applied to waste gate valves, exhaust brake valves, and other fluid control valves.

[0050]

The present invention has the following effects. (a) The valve opening (lift amount) can be adjusted independently of the working fluid for driving the valve simply by displacing the position of the stopper with an actuator or the like. The control is extremely simple and accurate as compared with the conventional valve device that adjusts the opening degree of the valve body.

(B) Therefore, if the present invention is applied to, for example, an EGR valve, the stopper is moved according to the load and the rotation speed of the engine, and the opening degree of the valve element is finely controlled, the exhaust gas recirculation amount (EGR rate) ) Is always an appropriate amount, and the NOx emission amount can be effectively reduced.

[Brief description of drawings]

FIG. 1 is a central longitudinal front view showing an example in which the present invention is applied to an EGR valve.

FIG. 2 is an enlarged cross-sectional plan view of a main part taken along the line AA in FIG.

FIG. 3 is an enlarged vertical cross-sectional front view of essential parts showing another embodiment in which a cylindrical bearing is provided with a thrust bearing.

FIG. 4 is a vertical cross-sectional front view of essential parts showing another embodiment in which a stopper is driven by a cam plate.

FIG. 5 is a central vertical sectional front view showing a conventional EGR valve.

[Explanation of symbols]

(1) EGR valve (4) Body (5) Reflux port (11) Cylinder (15) Piston (16) Pipe (17a) High pressure chamber (17b) Low pressure chamber (18) Compression coil spring (19) Valve guide (20) Valve body (20a) Shaft part (20b) Annular groove (20c) Umbrella part (21) Retainer (22) Cotter (23) Valve spring (24) Valve seat (30) Rib (31) Spring bearing (32) Seal member ( 33) Cylindrical part (33a) Male screw (34) Lift adjustment cylinder (34a) Cylindrical stopper (34b) Gear (34c) Female screw (35) Support piece (35a) Support cylinder (36) Sector gear (36a) Board (36b) V Groove (37) Pin (38) Backlash prevention member (39) Snap ring (40) Drive wire (41) Locking piece (42) Locking groove (43) Torsion coil spring (44) Annular groove (45) Stop Ring (reception part) (46) Thrust bearing (47) Cam plate (47a) Cam surface (48) Drive rod (49) Compression coil spring (A) Actuator (valve drive means)

Claims (6)

[Claims] 1. A fluid flow port,
For fluid control, including a body that accommodates a valve body that opens and closes a port by reciprocating, and valve driving means that is attached to the body and that opens and closes the valve body by driving a shaft portion of the valve body. In the valve device, a stopper that abuts a receiving portion that is substantially integral with the shaft portion at a proper position of the body and restricts a maximum lift amount of the valve body is linked to an appropriate actuator, thereby A valve device for fluid control, which is provided so as to be movable in the axial direction of the. 2. A stopper is rotatably screwed into an outer peripheral surface of a cylindrical portion of a body for guiding a shaft portion of a valve body by inserting the shaft portion, and is rotated by meshing with a sector gear linked to an actuator. The fluid control valve device according to claim 1, wherein the valve device is adapted to be operated. 3. The fluid control valve device according to claim 2, wherein the screw of the screwing portion of the stopper and the cylindrical portion is a multiple thread. 4. The fluid control valve device according to claim 1, wherein a low friction member is provided on at least one of the portions of the receiving portion and the stopper that come into contact with each other. 5. The fluid control valve device according to claim 4, wherein the low friction member is a thrust bearing. 6. A stopper is slidably fitted to the outer peripheral surface of a cylindrical portion of the body for guiding the shaft portion of the valve body by inserting the shaft portion, and engages with a cam plate linked to the actuator. The fluid control valve device according to claim 1, wherein the fluid control valve device is movable in the axial direction by the.