JPH11294408A - Two-stage operating diaphragm type actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve regulation precision of first-stage and second-stage maximum stroke, to improve stability of a maximum stroke for a long period, and to improve durability. SOLUTION: When a negative pressure applied on a portion extending from a first negative pressure introduction tube 25 to a first negative pressure chamber 27 is gradually increased, a diaphragm 4 is moved above against the force of a spring 15, and moved togetherwith an actuation rod 10. The plane part 16a of a spring support member 16 is forced into contact with the lower end of a first regulation screw 20 at a constant negative pressure and reaches a first-stage maximum stroke. Further, a negative pressure in a first negative pressure chamber 27 is increased and a negative pressure is also applied on a second negative pressure chamber 28, a diaphragm 5 is also moved upward against a spring 17. A second stage maximum stroke is determined in a way that the plane part 18a of a spring support member 18 is brought into contact with the lower end of a second regulation screw 23. The first screw 20 is regulated such that a tool is inserted through a hole 19 with a second regulation screw 23 removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-stage diaphragm actuator suitable for driving a variable nozzle of a turbocharger of an automobile internal combustion engine.

[0002]

2. Description of the Related Art A supercharging pressure control device for an internal combustion engine with a supercharger,
A variable nozzle that changes the inflow area of exhaust gas is provided, and when the throttle valve opening is small, the variable nozzle is fully closed.
When the accelerator pedal is depressed and the throttle valve opening increases, the driveability of the exhaust turbine is improved by increasing the driving force of the exhaust turbine by increasing the opening of the variable nozzle or the like. Is disclosed.

An actuator for operating this kind of variable nozzle has a structure in which a variable nozzle of a turbocharger is operated in one stage, and has no effect of an exhaust throttle. In order to provide the function of the exhaust throttle, a two-stage actuator is required, and further, the accuracy of the stroke of the actuator needs to be improved.

As a two-stage operation actuator, there is another two-stage operation diaphragm device disclosed in Japanese Utility Model Application No. 61-19455. The actuator includes first and second diaphragms that form first and second negative pressure chambers in a casing, and an operation rod that connects the first diaphragm to an operation target. A stopper member is provided at a central portion of the second diaphragm. The center portion of the first diaphragm can be abutted against the stopper by screwing.

[0005]

However, in the two-stage operation diaphragm device, a portion directly in contact with a stopper member for adjusting the first-stage operation stroke connects the operation rod to a shell of the first diaphragm. It is a swaged portion (the end of the operating rod).

Since the caulking portion of the operating rod has irregularities, it is not possible to precisely adjust the stroke in a vehicle mounted state.
There is a problem that the accuracy of the stroke can be expected at most about ± 1 mm.

Therefore, the present invention solves such a problem,
In both stages, the stroke can be strictly adjusted,
An object of the present invention is to provide a two-stage diaphragm type actuator suitable for operating a variable nozzle of a turbocharger of an internal combustion engine for a vehicle.

[0008]

In order to achieve the above object, a first aspect of the present invention is a two-stage diaphragm type actuator having an adjusting function for adjusting the stroke of each stage with an adjusting screw for each stage. , Wherein a spring receiving member having an abutting portion for abutting on the adjusting screw is provided on each of the diaphragms.

The maximum stroke of each diaphragm is determined by directly contacting the contact portion of the spring receiving member of each stage with the adjusting screw for each stage. Therefore, unlike the latter case of the prior art, the crimped portion of the operating rod does not come into contact with the uneven portion.

According to a second aspect of the present invention, in the two-stage operation diaphragm type actuator according to the first aspect, the contact portion of the spring receiving member is formed by a flat portion parallel to the central portion of the diaphragm. It is.

[0011] The flat portion forming the abutment portion allows more precise adjustment than the maximum stroke of each step. According to a third aspect of the present invention, in the two-stage operation diaphragm type actuator according to the first or second aspect, a hole for inserting an adjustment tool is formed at the center of the contact portion of the second-stage spring receiving member. A flat portion is formed on the substrate.

When adjusting the maximum stroke of the first-stage diaphragm by turning the first-stage adjustment screw, it can be easily adjusted by inserting an adjustment tool through the hole.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of the present invention will be described with reference to the drawings. In FIG. 1, the two-stage operation diaphragm type actuator 1 is mounted by being attached to an engine part of a vehicle by a bracket 2.

Shells 6 and 7 and shells 8 and 9 are superimposed on a first diaphragm 4 and a second diaphragm 5 whose periphery is airtightly fixed to a casing 3, respectively. Each upper end of the rod 11 is swaged.

10a is a caulked portion of the operating rod 10, 11
“a” is a caulked portion of the rod 11. In order to connect the operating rods 10 and 11 to the diaphragms 4 and 5, respectively, washers-like plates 12 and 13 are provided on the upper surfaces of the shells 6 and 8 provided on the upper surfaces of the diaphragms 4 and 5, respectively. And are crimped together with the diaphragm.

The operating rod 10 extends downward through the bracket 2, is inserted through a guide 14 provided on the bracket 2, and is configured to be vertically movable by being guided by the guide 14.

A compression coil spring 15 for urging the first stage diaphragm 4 downward is interposed between the upper surface of the peripheral portion of the first spring receiving member 16 and the lower surface of the partition wall 3a of the casing 3. . The spring support 16 is formed by pressing a metal plate into a cup shape so that a flat portion 16a parallel to the central portion of the diaphragm 4 is formed on the upper surface of the central portion.

A compression coil spring 17 for urging the second stage diaphragm 5 downward is interposed between the upper surface of the periphery of the second spring receiving member 18 and the lower surface of the ceiling of the casing 3. A hole (through hole) 19 for inserting an adjusting tool is formed in the center of the spring receiver 18, and a metal plate is cup-shaped so that a flat portion 18 a parallel to the center of the diaphragm 5 is formed on the upper surface around the hole 19. It is press-formed in a shape.

The rod 11 is provided so as to pass through a cylindrical guide 3b formed by extending the center of the partition 3a downward, and moves up and down while being guided by the guide 3b. A female screw is cut into the rod 11, and a first adjusting screw 20 is screwed into the female screw. An O-ring 21 is fitted in a circumferential groove formed around the head of the first adjusting screw 20, and is closely in contact with the inner peripheral surface of the rod 11. Acts as a lock.

A cylindrical guide 22 is fixed to the center of the upper part of the casing 3, and the female screw has a second adjusting screw 2.
An O-ring 24 for keeping the space between the second adjusting screw 23 and the guide 22 airtight is fitted into a circumferential groove formed around the head of the second adjusting screw 23. . The lower end of the second adjusting screw 23 faces the flat portion 18a of the spring receiver 18.

The actuator 1 operates by applying a negative pressure to the first negative pressure introducing tube 25 and the second negative pressure introducing tube 26. The negative pressure is supplied from a negative pressure source such as a negative pressure of an intake pipe of an engine, and a vacuum switching valve (V
SV) through the first negative pressure introducing tube 2 respectively.
5 or the second negative pressure introducing tube 26.

When a negative pressure is applied to the first negative pressure introducing tube 25 and the first negative pressure chamber 27 becomes a negative pressure, and the negative pressure applied to the diaphragm 4 exceeds a certain level, the diaphragm 4 is opposed to the spring 15. Moves upward. The flat portion 16a of the spring receiver 16 abuts on the lower end of the first adjusting screw 20 at a constant negative pressure, and the first stage has the maximum stroke.

Thereafter, when the negative pressure applied from the second negative pressure introducing tube 26 to the second negative pressure chamber 28 becomes greater together with the negative pressure applied to the first negative pressure chamber 27, the spring receiver 16 is opposed to the spring 17. The two diaphragms 4 and 5 move upward while abutting on the first adjusting screw 20, and the flat portion 18a of the spring receiver 18 abuts on the lower end of the second adjusting screw 23 at a constant negative pressure, thereby forming a two-stage. It is the maximum stroke of the eye.

FIG. 2 shows the relationship between the operating negative pressure and the stroke of the actuator during this time. Stroke A indicates the relationship between the maximum stroke of the first stage diaphragm 4 and stroke B
Is the maximum stroke of only the diaphragm 5 in the second stage, and the total maximum stroke of the actuator 1 is (stroke A) + (stroke B), and the operating rod 10 moves accordingly.

The lower chamber surrounded by the diaphragm 4 and the casing 3 is provided with an atmosphere communication hole 30 at the lower portion of the casing 3 so as to function as an atmospheric pressure chamber 29. Adjustment of the maximum stroke (stroke A) of the first stage is performed by inserting an adjustment tool such as a screwdriver from above through the center of the guide 22 and the hole 19 of the spring receiver 18 with the second adjustment screw 23 removed. The first adjustment screw 20 is rotated by engaging a tool with a groove in the head of the first adjustment screw 20.

After adjusting the maximum stroke of the first stage in this manner, the second adjusting screw 23 is screwed into the guide 22 as shown in the figure, and is turned with a tool such as a screwdriver to turn the maximum stroke (stroke B) of the second stage. ) To adjust.
In the embodiment, the accuracy of the entire maximum stroke is ± 0.25 mm
Improved to a degree.

By linking the tip (lower end in the figure) of the operating rod 10 to the variable nozzle of the engine turbocharger,
The effect of the exhaust throttle can also be realized.

[0028]

As described above, the two-stage operation diaphragm type actuator of the present invention is constructed as described above.
In the second stage, it is possible to strictly adjust the accuracy of the entire maximum stroke, and the effect of improving the accuracy of the stroke is great.

Further, unlike the latter case of the prior art, since the maximum stroke is not determined by the crimped portion having irregularities, the maximum stroke is determined by the flat surface of the spring receiving member. Durability is improved.

According to the second aspect of the present invention, the stability of the maximum stroke is improved, and the reliability of the actuator can be increased from that viewpoint. According to the third aspect of the invention, the adjustment is facilitated,
In addition, the maximum stroke of the second stage is more stable.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention.

FIG. 2 is a diagram illustrating a relationship between an operation negative pressure and a stroke according to the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Actuator 3 Casing 4 1st stage diaphragm 5 2nd stage diaphragm 15 1st stage spring 16 1st stage spring receiving member 16a Flat part as contact part 17 2nd stage spring 18 2nd stage spring Receiving member 18a Flat portion as contact portion 19 Hole 20 First adjusting screw 23 Second adjusting screw

Claims (3)

[Claims] In a two-stage diaphragm type actuator having an adjusting function of adjusting a stroke of each stage with an adjusting screw for each stage, a spring receiving member having an abutting portion abutting on the adjusting screw is provided on each diaphragm. A two-stage operation diaphragm type actuator characterized by being provided. 2. The two-stage operation diaphragm type actuator according to claim 1, wherein the contact portion of the spring receiving member is formed by a flat portion parallel to a center portion of the diaphragm. 3. The method according to claim 1, wherein a hole for inserting an adjusting tool is formed at the center of the contact portion of the second-stage spring receiving member, and a flat portion is formed around the hole. A two-stage diaphragm actuator.