JPH0410369Y2 - - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention A-1. Field of Industrial Application The present invention relates to a double strangler mechanism for a fully automatic choke-type carburetor.

A-2 Prior Art Conventionally, there is a device shown in FIGS. 4 to 6 as a chiyoke mechanism in a fully automatic chiyoke type carburetor. This device has an engine cooling water inlet passage 1 and an outlet passage 2, and as the temperature of the engine cooling water increases, the thermal expansion material inside the body expands and the operating rod 3 advances, and as the temperature decreases, the thermal expansion occurs. A temperature-responsive device 4 that causes the actuating rod 3 to retract as the material contracts; an actuating lever 6 that engages with the actuating rod 3 and rotates about a support shaft 5; and one end of the actuating lever 6. 6
a, a driven gear 9 is engaged with a drive gear 8 formed at the other end of the operating lever 6, one end 11a is engaged with the driven gear 9, and the other end 11b is engaged with a choke lever. The first engaging 10
It consists of a spring 11 and a fixed spring 13 that biases the operating lever 6 so that its drive gear 8 rotates in a direction that closes the yoke valve 12. When the engine water temperature becomes low, the operating rod 3 of the temperature-responsive device 4 retracts and the fixed spring 1
The actuating lever 6 is rotated counterclockwise by the force of 3, and the yoke valve 12 is moved in the closing direction via the first spring 11. When the temperature drops to 23°C, the yoke valve 12 is fully closed, and the temperature is further reduced to 23°C.
When the pressure decreases below, a closing moment of the choke valve is applied to the first spring 11. Also,
The engine water temperature rises from the low temperature state and reaches room temperature 23
℃, the closing moment of the first spring 11 disappears, and when the temperature rises above 23℃, the first spring 11 closes.
The opening of the check valve 12 is started via the spring 11, and the degree of opening of the check valve 12 is increased in proportion to the rising temperature. In this temperature range of 23° C. or above, when the valve 12 is opened to a degree greater than the degree of opening caused by the first spring 11, a closing moment acts on the first spring 11. Such a device is disclosed, for example, in Japanese Utility Model Publication No. 55-28856.

A-3 Problems to be solved by the present invention As in the prior art, the rotation of the chiyoke valve 12 is controlled by one first spring 1 provided on the driven gear 9.
1, if the load of the first spring 11 is set weakly, if a sudden opening force is applied to the spring 11 in a temperature range above room temperature, the spring 11 will open excessively and cause the spring 11 to open excessively. air-fuel ratio rich effect)
is not achieved, resulting in poor drivability.

Further, depending on the shape of the chiyoke valve, if the chiyoke effect is weak, there is a problem that the drivability at low temperatures is further deteriorated. Furthermore, if the load on the first spring 11 is simply increased in order to solve the above-mentioned problem, there is a problem that the closing moment of the choke valve increases at low temperatures, resulting in poor starting, and failure in emission due to an increase in the choke effect. Therefore, in the present invention, in addition to the first spring 11, the driven gear 9 is provided with a second spring that engages the choke lever 10 at a predetermined opening degree.
It is an object of the present invention to solve the above-mentioned problems by changing the closing moment for the choke valve in two stages depending on the temperature and the degree of opening of the choke valve.

B. Structure of the invention B-1 Means for solving the problems In order to solve the above-mentioned problems, the present invention provides a temperature-responsive device 4 that expands and contracts according to the temperature, and a temperature-responsive device 4 that expands and contracts according to the temperature. A driving gear 8 that rotates forward and backward; a driven gear 9 that meshes with the driving gear 8 and rotates forward and backward; and a first spring 11 that is fixed at one end to the driven gear 9 and at the other end to the chain lever 17. and a second spring 15 located on the rotation locus of the engagement piece 17a, which has one end fixed to the driven gear 9 and the other end formed on the jaw lever 17, and on the rotation side of the engagement piece 17a in the opening direction. an engagement surface 9b formed on the driven gear 9 to engage with the side surface of the engagement piece 17a at the other end of the second spring 15; It consists of a stopper lever 18 that restricts the amount of rotation toward the engaging piece 17a at the other end, and when the engaging piece 17a is fully closed at room temperature, the engaging piece 17a moves toward the stopper lever 18 to prevent the stopping valve from moving. The engaging surface 9b is located at a certain angle θ ₃ in the closing direction, and the engagement surface 9b is set apart from the stopper lever 18 by a certain angle θ ₂ in the opening direction of the valve. That is.

RO-2 Operation When the check valve 12 is fully closed at room temperature, each part is in the state shown in the figure. When the check valve 12 is opened in this state, the closing moment of the first spring 11 acts on the check valve 12 from the beginning of the opening operation, and the engagement piece 17a engages with the other end of the second spring 15 from a predetermined opening range. Thus, the closing moment of the second spring 15 is applied to the choke valve 12.

At a predetermined low temperature, the driven gear 9 rotates so that the engaging surface 9b is positioned on the stopper lever 18.

When the check valve 12 is opened from when the check valve 12 is fully closed at this low temperature, the closing moment of the first spring 11 acts on the check valve 12 during the gap between the engagement piece 17a and the stopper lever 18, and a predetermined level is reached. After the opening operation, the engagement piece 17a engages with the other end of the second spring 15, and a closing moment of the second spring 15 is applied. When the temperature is higher than the normal temperature state, the driven gear 9
rotates in the opening direction, and the first spring 11 operates to open the check valve 12. At the same time, the other end of the second spring 15 is moved in the opening direction by the engagement surface 9b by the opening amount, and the second spring 15 is rotated in the opening direction. A predetermined gap is maintained between the other end and the engagement piece 17a. Therefore, in this case as well, the closing moment of the first spring 11 acts at the initial stage of the opening operation of the check valve 12, and the closing moment of the second spring 15 is applied when the opening degree exceeds a predetermined value.

RO-3 Embodiment Next, an embodiment of the present invention shown in FIGS. 1 to 3 will be described.

Reference numeral 9 denotes a driven gear, which is rotatably mounted on a pin 14 fixed to the support member 14a and rotated in forward and reverse directions by the rotation drive mechanism shown in FIG. 4. A first spring 11 is wound around the outer periphery of the cylindrical portion 9a integrally formed with the driven gear 9, and one end 11a of the first spring 11 is fixed to the driven gear 9, and the other end 11b is fixed to the chain lever 17. In addition, the set load of the first spring 11 is set so that, at the rotational position of the driven gear 9 at room temperature of 23° C., the yoke valve 12 is held in a fully closed state and the closing moment on the yoke valve 12 is eliminated. .
A second spring 15 is wound around the outer periphery of the pin 14 inside the cylindrical portion 9a, and one end thereof is fixed to the cylindrical portion 9a by applying a predetermined torsional load, and the other end is bent. Rising part 15b
is engaged with an engagement surface 9b formed in a notch in the cylindrical portion 9a, and furthermore, at the tip of the rising portion 15b, a horizontal protrusion is provided so as to be located on the rotation locus of an engagement piece 17a formed on the jaw lever 17. A horizontal portion 15c is formed. Reference numeral 18 denotes a stopper lever integrally formed with the pin 14, which is connected to the second spring 1.
It is located and protrudes on the rotation locus of the rising portion 15b at 5. the second spring 15;
The positional relationship between the engaging surface 9b, the engaging piece 17a, and the stopper lever 18, which are placed in an engaging relationship with this, will be explained. At room temperature of 23° C., the engagement surface 9b formed on the driven gear 9 side is in the position shown in the figure, and the rising portion 15b of the second spring 15 is located at the position shown in the figure.
are engaged, and the horizontal portion 15c is in the position shown.

Engagement piece 17a formed on chain lever 17
is such that when the check valve 12 is fully closed, the horizontal part 15c of the second spring 15 at room temperature of 23°C is spaced by θ ₁ minute in the direction of rotation at low temperature, as shown in FIG. It is set. In the above state, the stopper lever 18 is connected to the horizontal portion 15c of the second spring 15.
On the other hand, this is set to be separated by θ ₂ in the direction _of rotation at low temperatures, as shown in FIG. 15c is the stopper lever 18
It is set so that it comes into contact with and prevents its rotation. And θ ₁ and θ ₂ at room temperature 23℃ are θ ₁
>θ ₂ , and the engaging piece 17a and the stopper lever 18 are set to have a gap of θ ₃ . Note that θ ₁ , θ ₂ , and θ ₃ can be set as desired depending on the formation positions of the engaging piece 17a and the stopper lever 18.

Next, the operation of the above embodiment will be explained.

At a room temperature of 23° C., the state shown in the figure is present, where the chi-yoke valve 12 is fully closed, the closing moment of the first spring 11 against the chi-yoke valve disappears, and the second spring 15 engages with the engagement surface 9b with accumulated return load. and the position shown. When the engine water temperature drops from this normal temperature state, the thermal expansion material in the temperature response device 4 contracts, the operating rod 3 moves to the right in FIG. 4, and the operating lever 6 moves counterclockwise around the support shaft 5. The drive gear 8 rotates counterclockwise. As a result, the driven gear 9 rotates clockwise, the first spring 11 is tightened, and a closing moment corresponding to the amount of rotation of the driven gear 9, that is, the amount of temperature decrease, is applied to the yoke valve 12. Further, due to the rotation of the driven gear 9, the engaging surface 9b thereof also rotates clockwise, and the rising portion 15b of the second spring 15 that is engaged with the engaging surface 9b also rotates accordingly, so that the horizontal portion 15c The lever 17 is rotated toward the engagement piece 17a. Then, when the engine water temperature drops to 20°C, the rising portion 15b of the second spring 15 rotates at an angle of θ ₂ and comes into contact with the fixed stopper lever 18 to prevent its rotation, and the second spring 15 is horizontally rotated. A gap is created between the portion 15c and the engagement piece 17a of the jaw lever 17 by an angle of θ ₃ . When the water temperature drops below 20°C, the driven gear 9 further rotates clockwise, and its engagement surface 9b further rotates clockwise, but the second spring 15
The rising portion 15b of the second spring 15 remains in contact with the fixed stopper 18, and the horizontal portion 15b of the second spring 15
5c remains at the above position and maintains a gap of θ ₃ from the engagement piece 17a. Therefore, at a temperature below 20° C., no closing moment is applied to the choke lever 12 by the second spring 15 unless the lever 12 is opened. Also, in this state of temperature below 20°C, if the check valve 12 is forcibly opened, the first spring 1 will move within the angle of θ ₃ .
A closing moment of 1 acts on the valve 12 corresponding to the temperature, and at an opening angle of θ ₃ or more, a closing moment of the second spring 15 is added to the closing moment of the first spring 11 corresponding to the temperature. be done.

Next, when the engine water temperature rises from the aforementioned low temperature state, the thermal expansion material of the temperature response device 4 expands, the operating rod 3 moves to the left in FIG. The driving gear 8 rotates clockwise, and the driven gear 9 rotates counterclockwise. When the water temperature rises to 20° C., the engaging surface 9b of the driven gear 9 comes into contact with the remaining second spring 15 as described above, and the closing moment of the first spring 17 also decreases in proportion to the temperature. When the water temperature further increases and the engaging surface 9b further rotates counterclockwise, the engaging surface 9b pushes the rising portion 15b of the second spring 15 to the left and separates it from the stopper lever 18. When the water temperature rises to room temperature 23℃, the second spring 15
The horizontal part 15c is the engagement piece 1 of the chiyoke valve 17.
At the same time as the first spring 11 is positioned at an angle of θ ₁ with respect to 7a, the closing moment of the first spring 11 that has been acting thus far disappears, and the first spring 11 becomes free.

When the room temperature reaches 23° C. or more, the driven gear 9 further rotates counterclockwise, and its engagement surface 9b moves the horizontal portion 15c of the second spring 15 to the left by the amount of rotation, and simultaneously engages the first spring. 11 rotates the check lever 17 and the check valve 12 in the opening direction by the amount of rotation. Therefore, at room temperature 23
℃ or higher, the horizontal portion 15 of the second spring 15 will close unless the chiyoke valve 12 is forcibly opened.
c and the engagement piece 17a of the jaw lever 17 is maintained at an angle of θ ₁ and rotated. This normal temperature 23
When the yoke valve 12 is forcibly opened in the temperature range of ℃ or above, the yoke valve 12 is opened in the range of θ ₁ .
Only the closing moment of the first spring 11 acts on the valve 12, and both the closing moment of the first spring 11 and the closing moment of the second spring 15 act on the valve 12 in the range of θ ₁ or more. Incidentally, the characteristics of the engine water temperature, the opening degree of the choke valve, and the closing moment of the choke valve are as shown in FIG.

In the figure, straight line A is the closing moment given by the first spring 11 when the opening of the choke valve is fully closed in the range from low temperature to room temperature 23°C. 1
The dashed dotted line B is the closing moment when the intake negative pressure acts to open the valve opening at a certain level or more in the range from low temperature to normal temperature, and is given by the first spring 11 and the second spring 15.

C. Effects of the invention As described above, according to the invention, the first spring is activated during the initial forced opening operation due to intake negative pressure of the chiyork valve or when the chiyork valve is fully closed (i.e., opening below a certain level) over a temperature range from low temperature to room temperature. Since only a weak closing moment acts on the engine, it is possible to improve the startability of the engine when the engine water temperature is below room temperature, and at the same time, it is possible to reduce Co emissions by reducing the chiyolk effect at temperatures above room temperature. can. Also,
When the opening of the check valve exceeds a certain level, the closing moment of the second spring is applied in addition to the closing moment of the first spring to increase the closing moment on the check valve, making it difficult to open the check valve, resulting in a check effect. This has the advantage of increasing drivability.

[Brief explanation of the drawing]

FIG. 1 is a plan view of the main parts showing an embodiment of the present invention;
Fig. 2 is a plan cross-sectional view of the driven gear section, Fig. 3 is an explanatory view taken from line A-A in Fig. 1, Fig. 4 is a side view of the drive mechanism that drives the device of the present invention, and Fig. 5 is a cross-sectional view of the driven gear section. FIG. 6 is a plan view of the conventional structure, FIG. 6 is a plan cross-sectional view of the driven gear portion, and FIG. 7 is a characteristic diagram of engine water temperature, the opening degree of the choke valve, and the closing moment of the choke valve. 4... Temperature response device, 8... Drive gear, 9...
Driven gear, 9b... Engaging surface, 11... First spring, 12... Chiyoke valve, 15... Second spring, 17... Chiyoke lever, 17a...
Engagement piece, 18...Stopper lever.

Claims (1)

[Scope of utility model registration request] a temperature-responsive device 4 that expands and contracts depending on the temperature;
A drive gear 8 rotates in forward and reverse directions as the temperature responsive device 4 expands and contracts; a driven gear 9 meshes with the drive gear 8 and rotates in the forward and reverse directions; one end is fixed to the driven gear 9 and the other end is fixed to the driven gear 9; a first spring 11 fixed to the lever 17; and an engagement piece 1 having one end fixed to the driven gear 9 and the other end formed on the lever 17;
The second spring 15 is positioned on the rotational trajectory of the engagement piece 7a and on the rotation side of the engagement piece 17a in the valve opening direction, and the second spring 15 is engaged with the side of the engagement piece 17a at the other end of the second spring 15. an engaging surface 9b formed on the driven gear 9, and a stopper lever 18 that is fixed to the carburetor main body side and restricts the amount of rotation of the other end of the second spring 15 toward the engaging piece 17a. Therefore, when the check valve 12 is fully closed at room temperature, the engaging piece 17a
is located at a certain angle θ ₃ away from the stopper lever 18 in the direction of closing the check valve, and the engagement surface 9b is separated by a certain angle θ ₂ away from the stopper lever 18 in the direction of opening the check valve. A double strangler mechanism of a fully automatic chiyoke type carburetor, which is characterized by being set so as to be located at the same position.