JPS6212949Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a negative pressure responsive flow control valve (hereinafter referred to as VCV) suitable for blow-by gas flow control. In automobiles, blow-by gas in the crankcase is guided into the intake manifold to purify harmful gas components. However, if blow-by gas enters the intake manifold when the engine temperature is low, problems such as a decrease in engine output will occur. Therefore, consideration must be given to prevent the negative pressure of the intake manifold from acting on the blow-by gas flow rate control member when the engine is at a low temperature. Conventionally, a bimetal negative pressure switching valve (hereinafter referred to as BVSV) was used as one solution to this problem.
The BVSV was located outside the VCV main body, and was functionally connected to the VCV main body using rubber hoses. Therefore, there was a problem in that piping was required and a space occupied by the independent functional member including the piping was required. That is, as shown simply in FIG. 1, the negative pressure chamber 1 and the atmospheric chamber 2 are airtightly separated by the diaphragm 3. 4 is a BVSV, which is functionally connected to the negative pressure chamber 1 and the atmospheric chamber 2 through pipings 5 and 6, respectively.

Therefore, Japanese Patent Application Laid-open No. 150123/1983 discloses a valve device in which the BVSV is compactly incorporated into the VCV so that the temperature signal and the negative pressure signal can be controlled in one product.

However, this valve device detects the temperature within the body due to heat conduction through the body, and when the temperature reaches a predetermined value, the pressure difference between the negative pressure chamber and the atmospheric chamber divided within the body disappears by the diaphragm. A bimetallic valve is provided to switch the direction in which the atmosphere is introduced into the negative pressure chamber, and there are two passages, one opening from the atmospheric chamber to the atmosphere and the other opening from the negative pressure chamber to the atmosphere via the bimetallic valve and filter. The two air introduction passages are not unified, and a bimetallic valve is installed in the body that forms the negative pressure chamber to provide the BVSV function. If an adjustment screw is provided for adjustment, the size of the valve device will inevitably increase. Furthermore, since the atmospheric chamber opens directly to the atmosphere, there is a risk that dust may enter the valve device from the outside, shortening the life of the valve.

Therefore, this invention aims to make this BVSV compact.
The purpose is to provide a negative pressure response flow control valve that can be incorporated into the diaphragm of a VCV to control temperature signals and negative pressure signals with one compact product, and which eliminates the above-mentioned problems of conventional devices. do.

Hereinafter, the present invention will be explained based on FIG. 2.

A is a central vertical sectional view of the entire assembly of the negative pressure responsive flow control valve for blow-by gas flow control according to the present invention. 7, 8, and 9 are body No. 1, 2, and 3, respectively.
7a is a negative pressure passage provided in No. 1 body 7, 8a and 8b are atmospheric pressure passages and blow-by gas passages provided in No. 2 body 8, and 9a is an intake provided in No. 3 body. This is the passage to the manifold.

10 is a negative pressure chamber, which communicates with the signal negative pressure passage 7a;
Reference numeral 11 denotes an atmospheric chamber which communicates with the atmospheric passage 8a. A diaphragm 12 is fixed at its inner periphery to the piston 13 and at its outer periphery to the No. 1 and No. 2 bodies 7 and 8 to airtightly isolate the negative pressure chamber 10 from the atmospheric chamber 11. A piston lid 14 is integrated with the piston 13, has a through hole 14a, and has a cave 15 formed therein. A bimetal device consisting of a sealing member 16, a disc-shaped bimetal 17, and a bimetal support spring 18 is housed within the cave 15.

19 is a spring that urges the piston 13 in one direction; 20 is a support member for the spring 19; and 21 is an adjustment screw for the spring 19 screwed into the No. 1 body 7.

A pipe 22 has a through hole 22a and is sandwiched approximately in the middle by a diaphragm.One end of the pipe is tightly fitted into the stepped hole 13a of the piston 13, and the other end is inserted into a chamber 24 communicating with the blow-by gas passage 8b. It extends slidably in the axial direction.

25 is a valve that controls the blow-by gas flow rate from the chamber 24 to the passage 9a, and 26 is a spring acting on the valve 25.

The structure of the present invention is as described above, and the outline of its operation will be described next. The state shown in FIG. 2 corresponds to when the engine is at high temperature, the bimetal 17 is in a closed state, and therefore the negative pressure of the negative pressure passage 7a is communicated with the negative pressure chamber 10. Therefore, the piston 13 moves according to the magnitude of the negative pressure to adjust the opening degree of the valve 25. In contrast to this state, when the engine temperature is low, the bimetal 18 reverses and performs an opening action, and the atmospheric chamber pressure side and the negative pressure chamber pressure side are brought into communication. Thus, piston 13 as well as valve 25
etc. are held in the state shown in the second figure by a spring 19.

In this invention, the important bimetal device that controls these functions is incorporated into the VCV diaphragm, so it does not require installation space or piping, etc., as in the past. In addition, the adjustment screw that adjusts the opening/closing set pressure of the VCV can be easily installed on the negative pressure chamber side without requiring an enlarged valve device, and the atmosphere introduction passage can be connected to the air cleaner. Because the valve is integrated into a single passage that communicates with the valve, it is possible to obtain a highly reliable and durable valve device without the risk of dust entering the valve device from outside and shortening the valve device's life. , it has become possible to provide a simple negative pressure responsive flow control valve device that solves the problems seen in conventional products.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of a conventional device, and FIG. 2 is a central vertical sectional view of the device of the present invention. 1: Negative pressure chamber, 2: Atmospheric chamber, 3: Diaphragm,
4: Bimetal negative pressure switching valve, 5: Piping,
6: Piping, 7/8/9: Body, 10: Negative pressure chamber, 11: Atmospheric chamber, 12: Diaphragm, 1
3: Piston, 17: Bimetal, 22: Pipe, 23: Diaphragm, 25: Valve.

Claims (1)

[Scope of utility model registration request] A body comprising a negative pressure passage communicating with a negative pressure source, an atmospheric pressure passage communicating with an air cleaner, and input and output passages, a negative pressure chamber opening to the negative pressure passage in the body, and the atmospheric pressure a diaphragm that partitions an atmospheric chamber opening into a passage; a piston fixed to the inner periphery of the diaphragm; a valve driven by the piston to control the communication flow rate between the input and output passages; A negative pressure responsive flow control valve comprising a passage communicating between a negative pressure chamber and an atmospheric chamber, and a bimetallic switching valve disposed within the passage and controlling opening and closing of the passage in response to temperature.