JPS5922288Y2 - Vaporizer diaphragm pressure control device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a device for controlling negative pressure so that more than necessary negative pressure does not act on the diaphragm of a vaporizer.

Various diaphragms are used in the carburetor, and the engine negative pressure is used to perform various operations and control the air-fuel ratio supplied to the engine.

The negative pressure passage for the diaphragm chamber is generally constructed as shown in FIG. 1, so that the negative pressure acting on the negative pressure source 3 acts directly on the diaphragm 7 through the negative pressure passage 4 and the negative pressure throttle 4a. ing.

Therefore, when extremely high negative pressure is applied, such as during engine idling or engine braking, a strong operating force is applied to the diaphragm 7.
The durability of the product was often damaged.

In order to correct such defects, a system has been proposed in which the negative pressure passage is communicated with the atmosphere through a check valve that opens at a certain level of negative pressure or higher, but the negative pressure at which the valve opens is determined by the precision of the parts. There were some drawbacks that required improvement.

To explain the drawings, 1 is a carburetor body, 2 is a throttle valve, 3 is a negative pressure source, 4 is a negative pressure passage, 4a is a negative pressure throttle, 5 is a diaphragm cover, 6 is a spring, and 7 is a diaphragm.

An atmospheric passage 11 is branched from the negative pressure passage 4, and a check valve A is provided in this branch, and a passage 12 connected to the atmosphere is provided at the tip of the check valve A.

In this check valve A, 8 is a valve, 9 is a spring that presses the valve 8, 10 is a lower cover, and 13 is an upper cover.

In the above structure, by appropriately determining the force of the spring 9 and the attachment of the lower cover 10, and setting the valve 8 so that it opens when a predetermined negative pressure is applied,
When the negative pressure acting on the diaphragm 7 exceeds a predetermined value, the negative pressure acts on the valve 8 through the atmospheric passage 11 and moves the valve 8 to the right in the figure.

As a result, the atmosphere flows from the passage 12 into the inside of the check valve A and into the atmosphere passage 11, and the negative pressure acting on the diaphragm 7 is alleviated.

Therefore, the durability of the diaphragm is improved because negative pressure exceeding a predetermined value is not applied to the diaphragm 7.

In check valve A with the above configuration, the spring force set is determined by the tolerance of the parts, and the value of the negative pressure at which check valve A opens may also be unstable, so in this invention, as shown in Fig. 3, A valve device is provided with an adjustment mechanism that adjusts the valve opening timing using negative pressure, the adjustment state of this adjustment mechanism can be maintained reliably, the entire valve device can be made compact, and the durability of the diaphragm can be improved. It is an object of the present invention to provide a diaphragm pressure control device having the following features.

That is, the above-mentioned valve device includes an upper cover 13 having an opening communicating with the atmospheric passage 12, a valve 8 housed in the upper cover and having a tapered tip and having a spring accommodation hole, and a valve 8 having one end inside the hole. A lower cover 10 is screwed into the upper cover that supports the spring 9 inserted into the spring 9 and the other end of the spring, and has an opening communicating with the atmospheric passage 11.
The present invention is characterized in that an O-ring 14 is provided between the lower cover 10 and the upper cover 13.

The passage 11 (pipe) is inserted and fixed into the opening of the lower cover 10, and the passage 12 is inserted into the opening of the upper cover.

As described above, in this invention, by providing the check valve A, when negative pressure acts on the diaphragm 7 more than necessary, the negative pressure can be relieved, thereby preventing unreasonable operation of the diaphragm 7. Of course, it has the feature of improving its durability, but especially in this invention, the lower cover 10 screwed onto the upper cover 13 also serves as the support member for the pressure spring 9 in the check valve A. Moreover, the spring 9 is adjusted by removing the passage 12 from the opening of the upper cover 13 and rotating the upper cover 13 with the opening of the lower cover 10 fixed, thereby moving the lower cover 10 forward and backward relative to the valve 8. Since this can be done by changing the amount of deflection of the spring 9, by adjusting the force of this spring 9 and controlling the opening pressure of the valve 8, the stroke of the diaphragm 7 can be controlled in size. .

Therefore, in a carburetor, when used in an accelerating diaphragm, it is possible to adjust the accelerated combustion discharge amount, and when used in a choke breaker mechanism, the opening degree of the choke valve can be finely adjusted. In addition, even if the accuracy of parts is relaxed, high-precision characteristics can be obtained, and the valve opening timing can be easily obtained based on a predetermined negative pressure, and an O-ring is provided between the upper cover 13 and the lower cover 10. Both 10.1
There is no way to prevent negative pressure from leaking between the three spaces, and the adjusted state is reliably maintained by preventing the screws from loosening.

Further, since the tip of the valve 8 is formed into a tapered shape, the beginning of the opening becomes a minute opening, eliminating hunting of the diaphragm and improving its soot resistance.

Furthermore, the valve 8 is provided with a spring housing hole and the spring is inserted into this hole, so that the spring can be supported reliably and the whole can be made smaller without being lifted up. It is extremely effective.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional type, FIG. 2 is a sectional view showing an embodiment of this invention, and FIG. 3 is a sectional view showing details of the check valve portion. 1... Carburizer, 3... Negative pressure source, 4...
...Negative pressure passage, 7...Diaphragm, 9.
...Spring, 10 ...Lower cover, 11
．． 12...Atmospheric passage, 13...Upper cover, A...Check valve.

Claims (1)

[Scope of utility model registration request] In a mechanism that operates the diaphragm of the carburetor by engine negative pressure, an atmospheric passage 11.12 is connected to the negative pressure passage 4 leading to the diaphragm chamber, and when a negative pressure of a predetermined level or more acts on the passage, the negative pressure opens the passage. An upper cover 13 having an opening communicating with the atmospheric passage 12 and a spring accommodation hole housed in the upper cover 13 have a tapered tip. It consists of a valve 8, a spring 9 with one end inserted into the hole, and a lower cover 10 which is screwed into the upper cover supporting the other end of the spring and has an opening communicating with the atmospheric passage 11. A diaphragm pressure control device for a carburetor, characterized in that an O-ring 14 is provided between the lower cover 10 and the upper cover 13.