JPS638863Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an ignition timing control device for an internal combustion engine, in particular, it takes negative pressure sources from several places and directly connects them to negative pressure sensors with different characteristics to control irregular ignition timing characteristics. The present invention relates to an ignition timing control device.

Originally, a problem with using a plurality of diaphragms to control the ignition timing in a plurality of negative pressure chambers is the reversal of the diaphragms. Inversion of the diaphragm during operation not only deteriorates the durability of the diaphragm itself, but also affects performance, which is extremely undesirable.

The following structures are available to prevent the diaphragm from reversing as described above.

The structure and operation will be explained below using diagrams.
In FIG. 1, a first casing 1, a second casing 2, and a cover 3 form the entire casing. The second casing 2 consists of two parts 2a, 2b
It consists of a first casing 1 and a second casing 2.
A first diaphragm 4 is held between the portions 2a. The inner diameter of the first casing 1 is the same as that of the second casing 2.
The part 2a is larger than the inner diameter of the part 2a of the first casing 1 when the first diaphragm 4 is clamped.
By protruding toward the side, the curved portion of the first diaphragm 4 is prevented from inverting toward the second casing 2 side. The second diaphragm 5 is circumferentially sandwiched between a portion 2b of the second casing 2 and the cover 3. 1b is an initial setter for the first diaphragm 4, 1a is an actuation stopper, 6 is a seat stopper, 7 is an actuation spring, and 8 is a rod. 9
is the rod of the second diaphragm 5 and projects outside the casing. 10 is a seat stopper, 11
is the actuation spring. A is a first negative pressure chamber to which a negative pressure inlet 12 is attached, and a negative pressure inlet 13 is also attached to the second negative pressure chamber entrance.

The structure of the conventional embodiment has been explained above. To explain the conventional operation below, negative pressure is taken in from different negative pressure sources of the engine into the independently provided negative pressure chambers A and B, and the two diaphragms 4 and 5 are operated independently. The characteristics are selected based on their combined operation. However, there is a problem that the curved part of the diaphragm 4 reverses during operation, and in order to change the bending point when the diaphragm 4 reverses, conventionally a second
There is one in which a protrusion 2c is provided on the inner circumference of the casing 2. However, providing protrusions on the inner periphery of the casing, which is a press-formed product, is a molding technique (jigs, etc.)
It is difficult, especially when the initial setter 1b of the first diaphragm 4 is integrally molded, the shape becomes complicated, which makes it more difficult and increases the cost. The present invention aims to solve the above problems, and one embodiment of the invention will be explained below using the drawings.
In FIG. 2, a protrusion 14a for preventing the curved portion of the first diaphragm 4 from reversing and an initial setter 1 for setting the setting position of the first diaphragm 4.
4b is integrally molded separately from the second casing 2, and the protrusion 14a is inscribed in the second casing 2. Other aspects are the same as the conventional configuration. The present invention has the above-mentioned configuration, but when compared with conventional products,
First of all, since the protrusion for preventing inversion is conventionally a press-molded product, its width is limited, and it is impossible to mold a product with a narrow width. However, since the device of the present invention is a separate body, it is possible to provide a projection with a narrow width, so that inversion can be prevented without damaging the effective diameter of the diaphragm during inversion. Next, the protrusions produced by press molding have a rough surface at the tip, which causes the diaphragm to wear out quickly, but with this invention, the surface that touches the diaphragm can be precisely finished, so it has less impact on the diaphragm and can provide a highly durable diaphragm. It is something.

[Brief explanation of the drawing]

FIG. 1 is a half-sectional view of the conventional product, and FIG. 2 is a half-sectional view of the product of the present invention.

Claims (1)

[Scope of utility model registration request] A diaphragm having a curved portion is stretched in a casing, negative pressure chambers are defined on both sides of the diaphragm, and the internal combustion engine is ignited according to the negative pressure introduced into each negative pressure chamber by the diaphragm. In the timing control device, a molded member integrally formed with a protrusion that supports the curved portion of the diaphragm and prevents the curved portion from reversing, and an initial setter that regulates the initial position of the diaphragm is disposed within the casing. An ignition timing control device for an internal combustion engine, characterized in that: