JPH09209839A - Constant vacuum type carburetor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deformation of a venturi forming part guide hole, a plate type guide groove and an air intake passage hole formed on a guide block at the time of forming the guide block of a synthetic resin material and fitting it in a guide block fitting hole of a carburetor main body. SOLUTION: A guide block G is formed of a synthetic resin material and is furnished with a venturi forming part guide hole 4, a plate part guide groove and an air intake passage hole 6. A first engagement part 11 orthogonal with a longitudinal groove with direction Y-Y of the plate part guide groove 5 is provided on one side outside surface 7A of an upper end part 7 of the guide block G facing the venturi forming part guide hole 4 and the plate part guide groove 5 and the other side outside surface 7B, and a second engagement part 12 is provided on a groove bottom part 5A of the plate part guide groove 5. The guide block G is fit in a guide block fitting hole 24, and the first engagement part 11 and the second engagement part 12 formed on the guide block G are inserted and arranged into a first engaged part 25 and a second engaged part formed on a carburetor main body corresponding to them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant-vacuum carburetor having a negative-pressure operating valve which moves up and down in an intake passage by a negative pressure generated in an intake passage upstream of a throttle valve. The pressure actuated valve is formed by a venturi forming portion and a plate-shaped portion protruding laterally from a side surface along a longitudinal axis of the venturi forming portion, and the negative pressure actuated valve is slidably mounted on the carburetor body. The present invention relates to a constant-vacuum vaporizer that is guided and held.

[0002]

2. Description of the Related Art A negative pressure actuated valve formed by a venturi-forming portion and a plate-like portion protruding laterally from a side surface along a longitudinal axis of the venturi-forming portion,
In particular, they are often used in recent years because they can improve the suction efficiency and shorten the total length of the vaporizer. In such a guide groove for slidingly guiding the negative pressure actuated valve, it is particularly difficult to form a plate-shaped portion guide groove for guiding the plate-shaped portion. For this reason, Japanese Patent Application Laid-Open No. 2-252950, filed by the present applicant, is disclosed. was suggested.

[0003]

According to the above prior art, there are the following problems. The cross-sectional shape of the guide block is such that a circular venturi forming portion guide hole is formed in the center at the upper end portion, and plate-shaped portion guide grooves that form rectangles from the side walls of the venturi forming portion guide hole toward both sides are formed. Is done. As described above, when the guide block is formed of a synthetic resin material in a state where the cross-sectional shapes of the holes are largely different, the venturi forming portion guide hole and the plate-shaped portion guide groove are deformed due to the uneven cross-sectional shape. However, it is difficult to maintain an accurate circular or rectangular shape, which is not preferable. Most of the plate-shaped portion guide groove is formed on the side of the intake passage hole (the side of the circular hole) formed perpendicular to the guide block. According to this, particularly at the lower end of the guide block, the thickness of the plate-shaped portion guide groove and the outer surface of the guide block becomes thicker than other portions. According to the above description, the inward shrinkage at the lower end of the guide block tends to be larger than that of other portions, whereby the length of the plate-shaped portion guide groove in the longitudinal groove direction or the diameter of the intake passage hole is reduced. It is not preferable because it may be deformed.

According to the constant-vacuum vaporizer of the present invention, a guide block having a vent hole forming portion guide hole, a plate-shaped portion guide groove, and an intake passage hole is formed of a synthetic resin material, and the guide block is formed by a vaporizer body. In the state where the guide holes are inserted into the guide block insertion holes, the deformation of the venturi forming portion guide holes, the plate-shaped portion guide grooves, and the intake passage holes is suppressed as much as possible to form and maintain accurate holes and groove shapes. An object of the present invention is to provide a constant-vacuum vaporizer that can be used.

[0005]

According to the present invention, there is provided a negative pressure operating valve for opening and closing an intake path in response to a negative pressure generated in an intake path upstream of a throttle valve. The operating valve is
The negative pressure operation is formed by a venturi forming portion having a diameter smaller than the diameter of the intake path, and a plate-like portion extending along the longitudinal axis of the venturi forming portion and extending outward from the outer periphery of the venturi forming portion. A constant vacuum slidably disposed in a guide groove of a guide block inserted into a guide block insertion hole recessed from the bottom of the atmosphere chamber of the carburetor body toward the bottom of the intake passage opposed thereto. In the vaporizer, a guide block formed of a synthetic resin material has a venturi forming portion guide hole formed at an upper end thereof for slidingly guiding the venturi forming portion, and a venturi is formed from the upper end to the lower end. A plate-shaped portion guide groove for slidingly guiding the plate-shaped portion toward the side from the formed portion guide hole is formed, and one side outer surface orthogonal to the longitudinal groove width direction of the plate-shaped portion guide groove. Between the other side outer side surface facing it,
An intake passage hole that penetrates perpendicularly to the intake passage hole is formed, and further, one side outer surface of the upper end portion of the guide block facing the venturi forming portion guide hole and the plate-shaped portion guide groove, and the other outer surface facing the plate, a plate is provided. A first locking portion orthogonal to the longitudinal groove width direction of the guide portion guide groove is provided, and a second locking portion is provided at the bottom of the groove of the plate-like guide groove, and the guide block is fitted into the guide block fitting hole. In addition, the first locking portion and the second locking portion formed on the guide block are inserted and arranged in the first locked portion and the second locked portion formed on the carburetor body correspondingly. This is the feature of 1.

The present invention, in addition to the first feature, further comprises an upper opening of the guide block insertion hole which opens to the bottom of the atmosphere chamber, and an outer surface of an upper end of the guide block which is inserted into the upper opening. A second feature is that a seal member is disposed between the two.

[0007]

According to the first feature, the venturi forming portion guide hole and the plate-shaped portion guide groove open at the upper end of the guide block, and are formed on one outer surface and the other outer surface of the upper end of the guide block. A first locking portion is provided. When the guide block is inserted into the guide block insertion hole of the carburetor body, the first
Since the locking portion is inserted and arranged in the first locked portion formed in the carburetor body, deformation of the cross-sectional shapes of the venturi forming portion guide hole and the plate-shaped portion guide groove is suppressed, and accurate holes and grooves are formed. The shape is obtained. Further, since the second locking portion provided at the groove bottom of the plate-shaped portion guide groove is inserted and arranged in the second locked portion of the carburetor body, deformation of the plate-shaped portion guide groove and the intake passage hole is suppressed. And accurate groove and hole shapes are obtained.

Further, according to the second feature, it is possible to suppress the leakage from the intake path to the atmosphere chamber through the insertion gap formed between the guide block insertion hole and the guide block, so that the air chamber can have a good size. It can be kept at atmospheric pressure.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a constant vacuum type vaporizer according to the present invention will be described below with reference to the drawings. 1 is a perspective view showing a negative pressure operated valve, FIG. 2 is a perspective view showing a guide block, FIG. 3 is an upper plan view of the guide block, FIG. 4 is a front view of the guide block of FIG. 3, and FIG. FIG. The negative pressure actuated valve P has a Venturi forming portion 1 having a diameter smaller than a diameter A (described later) of an intake passage penetrating a carburetor body at a central portion, and a longitudinal axis of the Venturi forming portion 1. The lower plate 3 is formed by a plate-shaped portion 2 extending outward from the outer periphery 1A of the venturi forming portion 1 along the line XX, and a disk-shaped lower plate 3 extending laterally is formed near the upper end thereof. .

The guide block G is injection-molded from a synthetic resin material and comprises the following. In guide block G,
Venturi forming portion guide hole 4, plate-shaped portion guide groove 5,
An intake passage hole 6 is formed. The venturi forming portion guide hole 4 is a sliding guide hole for slidably holding the venturi forming portion 1 of the negative pressure actuated valve P. The venturi forming portion guide hole 4 is vertically located at the upper end 7 of the guide block G. The upper part is opened at the upper end 8. The plate-shaped portion guide groove 5 is a sliding guide hole for slidably guiding and holding the plate-shaped portion 2 of the negative pressure actuated valve P. The plate-shaped portion guide groove 5 is provided with a venturi forming portion guide hole 4. And extends toward both sides and reaches near the upper end 8 to the lower end 9. The intake passage hole 6 has a hole shape corresponding to the shape of the intake passage penetrating the carburetor body, and has one side outer surface 10 in a direction ZZ orthogonal to the longitudinal groove width direction YY of the plate-shaped portion guide groove 5.
A is formed penetrating from A to the other outer surface 10B. The intake passage hole 6 is formed along ZZ.

The guide block G further includes a first locking portion 1
The first and second locking portions 12 are formed. The first locking portion 11
It faces the venturi forming portion guide hole 4 and the plate-shaped portion guide groove 5. An outer surface 7A on one side of the upper end 7 of the guide block G;
It is formed on the other outer surface 7B opposite thereto and is formed along a direction Z-Z orthogonal to the longitudinal groove width direction Y-Y of the plate-shaped portion guide groove 5. First in this embodiment
The locking portion 11 is an enlarged locking portion 11A formed on the outer side.
Formed by a reduced connecting portion 11B connecting the enlarged locking portion 11A and the one outer surface 7A or the other outer surface 7B of the upper end portion 7, and a clearance groove 11C formed in the enlarged locking portion 11A. In this example, both outer surfaces 7A and 7B of the right plate-shaped portion guide groove 5 and the venturi forming hole 4 in FIG.
Are formed so as to face both outer surfaces 7A and 7B and both outer surfaces 7A and 7B of the left plate-shaped portion guide groove 5, respectively.

The second locking portion 12 is formed at the groove bottom 5A of the plate-shaped portion guide groove 5. The second locking portion 12 in this embodiment penetrates from the groove bottom 5A toward the lower end 9. A groove bottom 5A of the right plate-shaped guide groove 5 and a left plate-shaped guide groove 5 in FIG.
Are formed in the groove bottom 5A.

The constant vacuum vaporizer is assembled as follows. The vaporizer is shown in FIGS. The carburetor body 20 penetrates sideways to form an intake passage 21,
A throttle valve 23 attached to a throttle valve shaft 22 rotatably supported by the carburetor body 20 is disposed in the downstream intake passage 21. At the upper side of the vaporizer main body 20, an air chamber recess 20A is provided.
Is opened upward, and a guide block fitting hole 24 corresponding to the outer shape of the guide block G is formed from the bottom portion 20B (which is a bottom portion of an atmospheric chamber described later) to the bottom portion of the intake path 2. . The guide block fitting hole 24 opens to the bottom 20B of the recess 20A in the atmosphere chamber. Further, a first locked portion 25 for inserting the first locking portion 11 of the guide block G is formed in the bottom portion 20C of the atmosphere chamber concave portion 20A so as to correspond to the first locking portion 11. The first locked portion 25 in the present embodiment is a reduced connecting portion insertion hole 25B for inserting the reduced connecting portion 11B toward the side from the guide block fitting hole 24.
And an enlarged locking portion insertion hole 25 into which the enlarged locking portion 11A is inserted
A is connected continuously.

A second locked portion 26 for inserting the second locking portion 12 of the guide block G corresponds to the second locking portion 12 at the bottom 24A below the guide block insertion hole 24. Protruding. The second locked portion 26 in the present embodiment is formed as a protrusion 26A protruding upward from the bottom 24A.

The air chamber recess 20 of the vaporizer body 20
The guide block G is fitted and arranged, for example, in a lightly press-fitted state in the guide block fitting hole 24 opened in the bottom portion 20B of A. According to this, the first locking portion 11 formed on the guide block G is enlarged. The locking portion 11A is inserted into an enlarged locking portion insertion hole 25A as a first locked portion 25 formed in the bottom 20B of the carburetor body 20, and the reduced connecting portion 11B is connected to the reduced connecting portion. It is inserted and arranged in the insertion hole 25B. Further, a projection 26A as a second locked portion 26 provided at the bottom 24A of the guide block fitting hole 24 is inserted into a through hole as the second locking portion 12 provided at the groove bottom 5A of the guide block G. Was placed.

According to the above, the guide block G is fitted and arranged in the guide block fitting hole 24 of the carburetor body 20, and the first locking portion 11 formed on the guide block G at this time is formed on the carburetor body 20. The second locking portion 12 is inserted and arranged in a second locked portion 26 formed in the carburetor body 20, and the intake passage hole 6 is further inserted into the vaporized passage hole 6. It opens corresponding to the intake path 21 of the container body 20. Thus, the guide block G is inserted into the guide block insertion hole 2.
4 is fixedly arranged. This situation is best illustrated in FIG.

A negative pressure actuated valve P having a diaphragm 30 as a partition attached to the upper end thereof is disposed in the guide block G. The venturi forming part 1 of the negative pressure actuated valve P is a venturi forming part. The plate portion 2 is slidably guided and held in the guide hole 4, and the plate portion 2 is slidably guided and held in the plate portion guide groove 5.

A cover 31 is arranged and fixed on the outer peripheral surface of the diaphragm 30, whereby an atmosphere chamber 32 is formed by the diaphragm 30 and the air chamber recess 20A, and the pressure receiving chamber is formed by the diaphragm 30 and the cover 31. 33 is formed.

A constant-vacuum vaporizer is formed as described above. Negative pressure generated in the intake passage 2 is introduced into the pressure receiving chamber 33 through the negative pressure introducing hole 34, and the negative pressure in the pressure receiving chamber 33 is reduced. In a state where the upward suction force due to the pressure and the downward spring force of the spring 35 contracted in the pressure receiving chamber 33 are balanced, the lower ends of the venturi forming portion 1 and the plate-like portion 2 and the intake air facing the lower end. The path 2 determines an appropriate opening area of the venturi V according to the negative pressure in the intake path 2.

Reference numeral 36 denotes a jet needle integrally attached to the negative pressure operated valve P, which is inserted into a needle jet 37 which opens to the intake passage 2 and is adapted to the degree of opening of the negative pressure operated valve P. The fuel gap is controlled. According to the constant-vacuum vaporizer according to the present invention, one side outer surface 7A of the upper end portion 7 of the guide block G facing the venturi forming portion guide hole 4 and the plate-shaped portion guide groove 5 of the guide block G, and opposing thereto. On the other outer surface 7B along the direction ZZ perpendicular to the longitudinal groove width direction YY of the plate-shaped portion guide groove 5.
A and a plurality of first locking portions 11 each including a reduced connecting portion 11B
When the guide block G is fitted into the guide block fitting hole 24 of the carburetor body 20, the first locking portion 11 </ b> A as the first locking portion 11 is drilled in the carburetor body 20.
The reduced connecting portion 11B is inserted into the enlarged locking portion insertion hole 25A as the locked portion 25 and the reduced connecting portion 11B is
B, the upper end 7 of the guide block G
The inward deformation of the venturi forming portion guide hole 4 in the above is prevented because the enlarged locking portion 11A is inserted into the enlarged locking portion insertion hole 25A and its movement is suppressed.
Further, the inward deformation of the groove width of the plate-shaped portion guide groove 5 is caused by the enlarged locking portion 11A being inserted into the enlarged locking portion insertion hole 25A.
The movement is prevented from being suppressed.

Therefore, especially the upper end 7 of the guide block G
In the above, although the shape of the guide hole for slidingly guiding the negative pressure actuating valve P is formed by a combination of a circle and a rectangle, and the shape of the guide hole is formed nonuniformly, the venturi forming portion guide hole 4 is accurately formed. It can be formed into a perfect circular shape, and the groove width of the plate-shaped portion guide groove 5 can be formed into an accurate constant groove width.

The provision of the escape groove 11C in the enlarged locking portion 11A means that the hole shape of the enlarged locking portion insertion hole 25A is smaller than that of the enlarged locking portion 11A, and the escape groove 11C is formed inward. When the enlarged locking portion 11A is inserted into the enlarged locking portion insertion hole 25A while being pressed and contracted, the enlarged locking portion 11A can be tightly inserted into the enlarged locking portion insertion hole 25A, and the occurrence of play during insertion can be suppressed.

On the other hand, a through hole serving as the second locking portion 12 is provided in the groove bottom portion 5A of the plate-shaped portion guide groove 5, and a bottom portion 24A of the guide block fitting hole 24 of the carburetor body 20 is provided in the through hole.
The protrusion 26A serving as the second locked portion 26 provided in the first portion is inserted and disposed, so that the plate-shaped portion guide groove 5 is prevented from being deformed inward toward the center of the intake passage hole 6. Is done.

Therefore, the length L (the length is shown in FIG. 8) of the opposed plate-shaped portion guide groove 5 in the longitudinal groove width direction YY can be kept constant, and the intake passage hole 6 Can be prevented from being deformed.

As described above, in the state where the guide block G is fitted into the guide block fitting hole 24 of the carburetor body 20, the venturi forming portion guide hole 4 and the plate-like portion guide near the upper end 7 of the guide block G. Groove 5
Can be accurately formed, and the length L of the plate-shaped portion guide groove 5 in the longitudinal groove width direction YY in the vicinity of the lower end 9 of the guide block G and the shape of the intake passage hole 6 can be accurately formed. Therefore, the negative pressure actuated valve P can be made extremely smooth and slidably guided.

In particular, when a synthetic resin material which is easily deformed when the guide block G is inserted into the guide block insertion hole 24 is used as the material of the guide block G, the above-mentioned effect is greatly exerted.

The fact that the deformation of the shape of the intake passage hole 6 of the guide block G can be suppressed by the second engaging portion 12 and the second engaged portion 26 means that the intake passage 21 of the carburetor body 20 and the intake The shape of the passage hole 6 can be surely matched, and the intake passage 21
This can contribute to the improvement of the atomization of the air-fuel mixture and the improvement of the intake efficiency without disturbing the air flow flowing inside.

In the constant vacuum type vaporizer, the outer peripheral portion of the guide block G and the guide block fitting hole 24 are provided.
It is preferable from the viewpoint of the dynamic characteristics of the negative pressure actuating valve P that the negative pressure in the intake passage 21 enters the atmosphere chamber 32 and changes the pressure in the atmosphere chamber 32 through the fitting gap between Not. In the present invention, the seal member F is disposed between the upper opening of the guide block fitting hole 24 to the bottom 20B of the atmosphere chamber 32 and the upper outer periphery of the guide block G.

In the present embodiment, a first locking step 40 facing downward is provided near the upper end 7 of the guide block G over the entire circumference of the guide block G, and the first locking step 40 is provided above the guide block fitting hole 24. A second locking step 41 facing the first locking step 40 is formed, and a rubber ring as a seal member F is arranged between the first locking step 40 and the second locking step 41. I do. When the guide block G is fitted into the guide block fitting hole 24, the seal member F is connected to the first locking step 40 of the guide block G and the second locking step 41 of the guide block fitting hole 24. The negative pressure in the intake path 21 enters the atmosphere chamber 32 through a fitting gap between the outer peripheral portion of the guide block G and the guide block fitting hole 24. This prevented the pressure in the atmosphere chamber 32 from changing.

The shapes of the first locking portion 11 and the second locked portion 25, or the shapes of the second locking portion 12 and the second locked portion 26 are limited to those in the above embodiment. In short, any shape may be used as long as deformation of the guide block G is suppressed.
Further, the cross-sectional shape of the negative pressure actuated valve P is not limited to the above embodiment, and a venturi forming portion having a diameter smaller than the diameter of the intake passage 21 and a plate-like portion extending from the venturi forming portion to both sides. What is necessary is just to be provided with.

[0031]

As described above, according to the constant-vacuum vaporizer according to the present invention, the guide block formed of a synthetic resin material has a venturi forming portion guide hole, a plate-shaped portion guide groove, and an intake passage hole. An outer surface on one side of the upper end portion of the guide block facing the venturi forming portion guide hole and the plate-shaped portion guide groove, and a second outer surface opposed to the upper end portion have a fourth surface orthogonal to the longitudinal groove width direction of the plate-shaped portion guide groove. A first locking portion is provided, a second locking portion is provided at the bottom of the plate-shaped portion guide groove, and the guide block is fitted into the guide block fitting hole, and the first locking portion formed on the guide block; Since the second locking portion is inserted and arranged in the first locked portion and the second locked portion formed on the carburetor main body correspondingly, the guide block is formed of a synthetic resin material, and the guide block is formed. The vaporizer book When inserted into the guide block insertion hole to be drilled, the shapes of the venturi forming portion guide hole, plate-shaped portion guide groove, and intake passage hole can be accurately formed, and the negative pressure operated valve can be slidably guided well. Further, the intake passage hole of the guide block can be accurately matched with the intake passage of the carburetor body, so that the mixture can be atomized and the intake efficiency can be improved. In addition, according to the arrangement of the seal member between the upper opening of the guide block insertion hole and the outer surface of the upper end of the guide block, the air intake through the gap formed between the guide block insertion hole and the guide block. Since the negative pressure in the road is prevented from entering the atmosphere chamber, the dynamic characteristics of the negative pressure operated valve can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a negative pressure operated valve used in a constant vacuum type vaporizer of the present invention.

FIG. 2 is a perspective view showing one embodiment of a guide block used in the constant vacuum vaporizer of the present invention.

FIG. 3 is an upper plan view of the guide block shown in FIG. 2;

FIG. 4 is a front view of the guide block shown in FIG. 3;

FIG. 5 is a right side view of the guide block shown in FIG. 4;

FIG. 6 is a vertical sectional view of a main part of the constant vacuum vaporizer according to the present invention.

FIG. 7 is a vertical sectional view of an essential part taken along line NN in FIG. 6;

8 is an upper plan view showing a state where a guide block is fitted into a guide block fitting hole of the vaporizer main body in the constant vacuum type vaporizer of FIG. 6;

[Explanation of symbols]

 P Negative pressure operated valve 1 Venturi forming part 2 Plate part G Guide block 4 Venturi forming part guide hole 5 Plate part guide groove 6 Intake passage hole 7 Upper end of guide block 8 Upper end of guide block 9 Lower end of guide block 11th 1 locking portion 12 second locking portion 20 carburetor body 20B bottom portion of air chamber 24 guide block insertion hole 25 first locked portion 26 second locked portion 32 air chamber F seal member

Claims (2)

[Claims] A negative pressure operating valve for opening and closing the intake path in response to a negative pressure generated in an intake path upstream of the throttle valve, wherein the negative pressure operating valve has a venturi having a diameter smaller than a diameter A of the intake path. And a plate-shaped portion extending along the longitudinal axis XX of the venturi-forming portion and extending outward from the outer periphery of the venturi-forming portion, and the negative pressure-operated valve is provided in the atmosphere of the vaporizer main body. A constant-vacuum vaporizer slidably disposed in a guide groove of a guide block inserted into a guide block insertion hole recessed from a bottom of the chamber toward a bottom of an intake passage facing the chamber; The guide block G formed of a material has an upper end 7.
A venturi forming portion guide hole 4 for slidingly guiding the venturi forming portion 1 is formed to be open, and an upper end 8 to a lower end 9 are formed.
, A plate-shaped portion guide groove 5 for slidingly guiding the plate-shaped portion 2 toward the side from the venturi forming portion guide hole 4 is formed, and is orthogonal to the longitudinal groove width direction Y-Y of the plate-shaped portion guide groove 5. An intake passage hole 6 penetrating at right angles is formed between the one outer surface 10A and the other outer surface 10B opposed thereto.
Further, one side outer surface 7A of the upper end portion 7 of the guide block G facing the venturi forming portion guide hole 4 and the plate-shaped portion guide groove 5
And a first locking portion 11 orthogonal to the longitudinal groove width direction Y-Y of the plate-shaped portion guide groove 5 is provided on the other outer surface 7B opposed thereto, and the first locking portion 11 is provided on the groove bottom portion 5A of the plate-shaped portion guide groove 5. The second locking portion 12 is provided, and the guide block G is fitted into the guide block fitting hole 24 and the guide block G
The first locking part 11 and the second locking part 12 formed on the first locked part 2 formed on the carburetor body 20 correspondingly.
A constant-vacuum vaporizer, wherein the vaporizer is inserted and arranged in the fifth and second locked portions 26. 2. A seal member between an upper opening of the guide block insertion hole 24 opening to the bottom 20B of the atmosphere chamber 32 and an outer surface of an upper end 7 of the guide block G inserted into the upper opening. The constant-vacuum vaporizer according to claim 1, wherein F is disposed.