JPH0680843U - Negative pressure responsive valve in constant vacuum carburetor - Google Patents

Abstract

(57) [Summary] [Purpose] It is easy to attach the diaphragm to the negative pressure responsive valve, and the negative pressure responsive valve can be reused. [Structure] Upper surface 1A of flange 1 for mounting negative pressure responsive valve P
Further, a locking groove portion 2C having a neck portion 2A having a diameter B and a groove width C and a locking step portion 2B extending toward the outer periphery of the engaging projection 2 is provided. In the central cylindrical portion 3 of the upper plate U formed of a synthetic resin material, the fitting hole 3B and the bottom of the fitting hole 3B have a diameter E through the locking step portion 3D and the groove width of the neck portion 2A. C
The locking projection 3E having the following length F is provided, and the central cylindrical portion 3
Lower surface 4A of the annular collar portion 4 which is G upward from the lower surface 3C of the
An annular groove 4B having a groove depth H reaching a position above the locking step portion 3D is drilled in this. Upper surface 1A of mounting collar 1
And the lower surface 4A of the annular collar 4, and the diaphragm S is fitted between the engaging protrusion 3E of the upper plate U and the engaging groove 2C of the negative pressure responsive valve P.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a carburetor that controls the amount and concentration of an air-fuel mixture supplied to an engine. Among them, in particular, the opening area of the intake passage that penetrates the carburetor main body is set according to the negative pressure state that occurs in the intake passage. The present invention relates to a constant vacuum carburetor controlled by a negative pressure operated valve that operates.

[0002]

[Prior art]

 The constant-vacuum carburetor has a negative pressure responsive valve guide tube connected to the intake passage that penetrates the carburetor body, and a negative pressure responsive valve with a diaphragm attached to the upper part of the negative pressure responsive valve guide tube. Is arranged movably, and an atmosphere chamber is formed by one side surface of the diaphragm and the concave portion of the carburetor main body, and a pressure receiving chamber is formed by the other side surface of the diaphragm and the cover covering it. This is disclosed in Japanese Patent Publication No. 4-67581. In such a constant vacuum carburetor, the diaphragm is fixed to the upper part of the negative pressure responsive valve as follows. A caulking cylinder portion having an annular locking step portion having a reduced diameter is formed on an upper portion of the negative pressure responsive valve, and an annular lower plate surrounding the caulking cylinder portion is formed on the locking step portion, A diaphragm and an annular upper plate are placed in sequence. Then, in such a mounted state, the upper end of the caulking tubular portion projects from the upper surface of the upper plate, and the lower plate, the upper plate and the upper plate are formed by rolling and caulking the upper end of the caulking tubular portion outward toward the upper surface of the upper plate. The diaphragm is caulked and fixed to the negative pressure responsive valve via the plate.

[0003]

[Problems to be solved by the device]

 According to the negative pressure responsive valve in the conventional constant vacuum type carburetor, the diaphragm is fixed to the negative pressure responsive valve by utilizing the plastic deformation of the caulking tubular portion integrally formed with the negative pressure responsive valve and the metal material. Rolling caulking causes chips to be generated during the caulking work, and each chip removal work is required after the caulking work, which hinders improvement of production efficiency. Further, if a problem occurs in the caulking work, the negative pressure responsive valve cannot be reused, which impairs the economical efficiency. The present invention has been made in view of the above problems, and an object of the present invention is to provide a negative pressure responsive valve in a constant-vacuum carburetor in which the work of fixing the diaphragm is easy and the negative pressure responsive valve can be reused. And

[0004]

[Means for solving the problem]

 In order to achieve the above-mentioned object, the present invention provides a negative pressure responsive valve guide cylinder continuously in an intake passage that penetrates the carburetor main body, and a negative pressure responsive valve guide cylinder has a diaphragm fixed above the negative pressure responsive valve guide cylinder. In a constant-vacuum carburetor in which a pressure responsive valve is movably arranged, an atmosphere chamber is formed by one side surface of the diaphragm and the carburetor main body concave portion, and a pressure receiving chamber is formed by the other side surface of the diaphragm and a cover covering it. , On the upper part of the negative pressure responsive valve, form a mounting collar part that is formed of a thin annular ring that extends toward the outside, and a cylindrical engaging protrusion that has an outer diameter A toward the upper side of the mounting collar part. The engaging protrusion is provided with a neck portion having a diameter B and a groove width C upward from the upper surface of the mounting flange portion, and a locking step portion extending from the upper end of the neck portion to the outer periphery of the engaging protrusion. Provided with a locking groove, while using a synthetic resin material The upper plate thus formed is formed by a central tubular portion and an annular flange portion that extends outward from the central tubular portion. The central tubular portion has an engaging protrusion that extends downward from its upper surface. The fitting hole has a diameter D that is substantially the same as the outer diameter A, and the diameter is reduced from the bottom of the fitting hole through the locking step, and the diameter E is substantially the same as the diameter B of the neck portion. And a locking protrusion having a length F less than the groove width C of the neck portion and opening to the lower surface of the central cylindrical portion, and further, an annular collar portion positioned G above the lower surface of the central protrusion. An annular groove having a groove depth H that reaches a position above the locking step of the locking projection is bored on the lower surface of the, and the upper surface of the flange of the negative pressure responsive valve and the annular flange of the upper plate U are formed. The diaphragm is placed between the lower surface of the part and the upper part of the annular rib formed inside the diaphragm. With the locking projection of the upper plate fitted into the engagement projection of the negative pressure responsive valve, the locking projection of the upper plate fits inside the neck of the negative pressure responsive valve in the annular groove of the door U. It is fitted and the locking step of the upper plate is locked to the locking step of the negative pressure responsive valve.

[0005]

【Example】

 An embodiment of a negative pressure responsive valve in a constant vacuum carburetor according to the present invention will be described below with reference to the drawings. Since the carburetor main body and the constant vacuum type carburetor in which the negative pressure responsive valve is arranged are known, they are omitted. The negative pressure responsive valve P will be described with reference to FIG. The negative pressure responsive valve P opens and closes the intake passage of the carburetor body and has a cylindrical shape or a rectangular shape. The negative pressure responsive valve P has a thin annular mounting collar portion 1 extending outwardly at the upper part thereof. Formed. A cylindrical engaging projection 2 having an outer diameter A is formed upward from the upper surface 1A of the mounting collar 1. The engaging protrusion 2 has a neck portion 2A having a diameter B and a groove width C upward from the upper surface 1A of the mounting collar portion 1, and an outer periphery of the engaging protrusion 2 from the upper end of the neck portion 2A. And a locking step portion 2B directed toward the front side are formed, and a locking groove portion 2C is formed by the neck portion 2A and the locking step portion 2B. In this example, a taper surface 2D is formed on the upper end of the engaging protrusion 2. U is an upper plate made of a synthetic resin material, and is formed by a central tubular portion 3 located on the center side and an annular flange portion 4 extending outward from the central tubular portion 3. The upper plate U is shown in FIG. A fitting hole 3B having a diameter D that is substantially the same as the outer diameter A of the engaging projection 2 of the negative pressure responsive valve P is formed in the central cylindrical portion 3 downwardly from the upper surface 3A thereof. The hole 3B does not reach the lower surface 3C of the central tubular portion 3) The diameter E of the fitting hole 3B is reduced from the diameter D of the fitting hole 3B through the locking step 3D, and the diameter of the neck 2A A locking projection 3E having a straight diameter E substantially the same as B and a length F equal to or less than the groove width C of the neck portion 2A opens on the lower surface 3C of the central tubular portion 3. Further, the lower surface 4A of the annular collar portion 4 is positioned G above the lower surface 3C of the central tubular portion 3, and the lower surface 4A of the annular collar portion 4 surrounds the central tubular portion 3 and has the locking projection 3E. An annular groove 4B having a groove depth H reaching the position above the locking step portion 3D is formed. That is, G + H> F. The G dimension described above is approximately equal to the film thickness of the diaphragm described later. S is a flexible diaphragm made of a rubber material or the like, and an annular rib 5A is formed in the central opening, and an annular film 5B is formed in an umbrella shape outward from the annular rib 5A. The diaphragm S is publicly known, and the diaphragm S is shown in FIG.

Next, the fixation of the diaphragm S to the negative pressure responsive valve P will be described. First, the annular rib 5A of the diaphragm S is inserted and arranged in the annular groove 4B of the upper plate U. According to this, the upper surface 5C of the membrane 5B of the diaphragm S is placed on the lower surface 4A of the annular collar portion 4 of the upper plate U. Will be placed. Next, the locking projection 3E of the upper plate U on which the diaphragm S is mounted is pressed toward the engagement projection 2 of the negative pressure reaction valve P. According to this, the diameter E of the locking projection 3E of the upper plate U is fitted into the outer periphery of the engagement projection 2 while being expanded, and when the pressing is further advanced, the locking projection 3E of the upper plate U is negatively operated. It is fitted into the engaging groove portion 2C of the P engaging protrusion 2. That is, the lower surface of the locking projection 3E of the upper plate U (in other words, the lower surface 3C of the central tubular portion 3) is locked to the upper surface 1A of the mounting collar 1, and the locking step 3D of the locking projection 3E is engaged. The inner diameter portion of the locking projection 3E of the upper plate U having the diameter E is locked to the locking step portion 2B of the locking groove portion 2C, and returns to the diameter E again, so that the neck portion 2A of the locking groove portion 2C is locked. Fit on the outer circumference. According to the above, the upper plate U can be reliably fixed to the negative pressure responsive valve P, whereby the annular rib 5A of the diaphragm S can be fixed between the annular groove 4B and the upper surface 1A of the mounting collar portion 1. Further, the film 5B of the diaphragm S can be fixed between the lower surface 4A of the annular collar portion 4 and the upper surface 1A of the mounting collar portion 1. In this way, the locking projection 3E of the upper plate U can be fitted into the locking groove 2C of the negative pressure responsive valve P only because the upper plate U is formed of a synthetic resin material and the annular flange 4 is formed. The lower surface 4A of the locking projection 3E is provided with an annular groove 4B having a groove depth H reaching the upper direction from the locking step 3D so that the elastic force of the synthetic resin material can be effectively used. This is due to the fact that

[0007]

[Effect of device]

 As described above, according to the negative pressure responsive valve in the constant-vacuum carburetor according to the present invention, when the diaphragm is attached to the negative pressure responsive valve, the upper plate is simply pushed toward the engaging projection and fitted. Since it can be done only by linear movement, it does not generate chips like rolling and crimping work, thus eliminating the need for any cleaning process after sticking work, thus improving production efficiency. Has been greatly improved. Also, if there is a problem in the fitting of the upper plate, it is only necessary to replace the upper plate and the expensive negative pressure responsive valve can be reused, which is economically effective. Is.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part showing an embodiment of a negative pressure responsive valve in a constant vacuum carburetor according to the present invention.

FIG. 2 is a vertical cross-sectional view showing an embodiment of an upper plate of a negative pressure responsive valve in a constant vacuum carburetor according to the present invention.

3 is a longitudinal cross-sectional view of a main part showing a state in which the negative pressure responsive valve of FIG. 1 is assembled with the upper plate of FIG.

[Explanation of symbols]

 P Negative pressure responsive valve 1 Mounting collar part 1A Upper surface 2 Engaging protrusion 2A Neck part 2B Locking step part 2C Locking groove part U Upper plate 3 Central cylindrical part 3A Upper surface 3B Fitting hole 3C Lower surface 3D Locking step part 3E Stop protrusion 4 Annular collar 4A Lower surface 4B Annular groove S Diaphragm 5A Annular rib

Claims (1)

[Scope of utility model registration request] 1. A negative pressure responsive valve guide cylinder is continuously provided in an intake passage passing through the carburetor main body, and a negative pressure responsive valve having a diaphragm fixed to its upper part is movable in the negative pressure responsive valve guide cylinder. In the constant-vacuum carburetor in which the one side surface of the diaphragm and the concave portion of the carburetor main body form an atmospheric chamber, and the other side surface of the diaphragm and the cover covering the same form the pressure receiving chamber, A mounting flange portion 1 formed of a thin annular shape extending outward is formed on the upper part, and a cylindrical engaging projection 2 having an outer diameter A is provided further upward from the upper surface 1A of the mounting flange portion 1, The engaging protrusion has a neck portion 2A having a diameter B and a groove width C upward from the upper surface 1A of the mounting flange portion 1 and a locking step portion 2B extending from the upper end of the neck portion 2A to the outer periphery of the engaging protrusion 2.
2C is provided, and on the other hand, the upper plate U formed of a synthetic resin material is formed by the central tubular portion 3 and the annular flange portion 4 extending outward from the central tubular portion 3. The fitting hole 3B, which has a diameter D that is substantially the same as the outer diameter A of the engaging projection 2, extends downward from the upper surface 3A of the central cylindrical portion 3.
And the diameter is reduced from the bottom of the fitting hole 3B through the locking step 3D, has a diameter E substantially the same as the diameter B of the neck 2A, and is less than or equal to the groove width C of the neck 2A. And a locking projection 3E opening to the lower surface 3C of the central tubular portion 3 with a height F, and further, the lower surface 4A of the annular flange 4 located G above the lower surface 3C of the central projection 3 is engaged. Locking step portion 3 of the stop projection 3E
An annular groove 4B having a groove depth H reaching a position above D is bored, and between the upper surface 1A of the flange portion 1 for mounting the negative pressure response valve P and the lower surface 4A of the annular flange portion 4 of the upper plate U. With the diaphragm S arranged and the annular rib 5A formed inside the diaphragm S mounted in the annular groove 4B of the upper plate U, the locking projection 3E of the upper plate U is engaged with the negative pressure responsive valve P. The engagement projection 3E of the upper plate U is fitted into the neck portion 2A of the negative pressure responsive valve P, and the engagement step 3D of the upper plate U is engaged with the negative pressure responsive valve P. A negative pressure responsive valve in a constant vacuum type carburetor that is locked to the stepped portion 2B.