JPH0422045Y2 - - Google Patents

Description

[Detailed explanation of the invention] A. Purpose of the invention A-1 Industrial application field This invention is a throttle control system for an air governor for an internal combustion engine used to control the engine speed of a spark-ignition internal combustion engine that uses gasoline, LPG, etc. as fuel. Regarding valves.

A-2 Prior Art Conventionally, as shown in FIG. 4, the air governor as described above has a
A throttle shaft 3 is rotatably mounted horizontally eccentrically from the center of the bore 2, and a throttle valve 4 is fixed to the throttle shaft 3. The shape of the throttle valve 4 is such that the throttle shaft 3 is designed to prevent the throttle valve 4 from engaging with the bore 2 when it is fully open.
Both end surfaces 4a and 4b in the axial direction of the throttle shaft 3 are cut out in a direction perpendicular to the axial direction of the throttle shaft 3, but other peripheral surfaces 4 other than the both end surfaces 4a and 4b are cut out.
c and 4d are the circumferential surface 4 of the throttle valve 4 so that it is in contact with the inner circumferential surface of the bore 2 when the throttle valve 4 is fully closed.
The radii of c and 4d are set to be the same as the radius of the inner peripheral surface of the bore 2. A throttle valve formed in this manner is disclosed, for example, in Japanese Utility Model Application Publication No. 1758/1983.

A-3 Problems to be solved by the present invention In the conventional throttle valve 4, when the throttle valve 4 is installed in the normal position where its center and the center of the bore 2 coincide,
When the throttle valve is fully closed rather than fully open, there is no interference with the bore 2 and there is no problem. If the shaft 3 is eccentric in the axial direction,
The intersection 4e between the end surface 4a or 4b and the circumferential surface 4c or 4d on the eccentric side may come into contact with the inner circumferential surface of the bore 2 and be pulled during the operation from the open state to the fully closed state. Since the governor is controlled by balancing minute forces such as the negative pressure in the engine's intake pipe and the flow of the air-fuel mixture, the resistance due to the above-mentioned sagging can be caused by poor governor reproducibility, excessive overshoot, etc. There is a problem that leads to poor performance. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems by preventing the throttle valve from becoming stuck.

B. Structure of the invention B-1 Means for solving the problems In order to solve the above-mentioned problems, the present invention aims to improve the bearing side inner surface 2a of the throttle shaft 3 in the bore 2 in the axial direction of the throttle shaft 3. The inner surface 2b of the bore 2 other than the inner surface 2a on the bearing side is formed into an arcuate surface, and the throttle valve 5 is provided in the bore 2. Among the front and rear end surfaces of the bore 2 facing the bearing side inner surface 2a, the end surfaces 5a and 5b of the portion where the throttle shaft 3 is located are linear surfaces that closely follow the bearing side inner surface 2a, and other than the end surfaces 5a and 5b. The remaining end faces 5e, 5f of
The left and right end surfaces 5c and 5d of the throttle valve 3, which are formed by cutting inward from the throttle valve a and 5b and are located on a line passing through the center of the throttle valve 5 and orthogonal to the throttle shaft 3, are connected to the throttle valve. When the throttle valve 3 is fully closed, the remaining left and right peripheral surfaces 5g and 5h other than the left and right end surfaces 5c and 5d are formed into a small circular arc surface that contacts the inner peripheral surface of the bore 2 when the throttle valve 3 is fully closed. It is characterized in that it is formed into an arcuate surface having a smaller diameter than the left and right end surfaces 5c and 5d so that a predetermined gap d is created between the inner surface of the left and right end surfaces 5c and 5d.

B-3 Embodiment Next, an embodiment of the present invention shown in FIGS. 1 and 2 will be described.

2 is the bore of the air governor, 3 is the bore 2
Throttle shaft eccentrically suspended inside, 5
is a throttle valve fixed to the throttle shaft 3. The front and rear end surfaces 5a and 5b of the throttle valve 5, which are repositioned in the axial direction of the throttle shaft 3, are formed in a linear plane orthogonal to the throttle shaft 3, and are formed in a small area where the throttle shaft 3 is located. has been done. Left and right end surfaces 5c, 5 located on a line passing through the center of the throttle valve 5 and perpendicular to the throttle shaft 3
d is the bore 2 when the throttle valve 5 is fully closed.
It is formed into an arcuate surface with a diameter that comes into contact with the inner surface 2b, and its width in the circumferential direction is formed in a small range. Further, the remaining end surfaces 5e and 5f located on the left and right sides of the front and rear end surfaces 5a and 5b are the same as the front and rear end surfaces 5.
The remaining left and right circumferential surfaces 5g and 5h, which are formed as linear surfaces with a smaller diameter than those of the left and right end surfaces 5c and 5d, are circular arcs with a smaller diameter than those of the left and right end surfaces 5c and 5d. These remaining end faces 5e, 5f and the remaining circumferential surface 5
g and 5h are formed along the bearing-side inner surface 2a and inner surface 2b of the bore 2 with a predetermined gap d when the throttle valve 5 is fully closed.

In FIG. 3, the bearing of the throttle shaft 3 is a ball bearing 6 that can withstand thrust loads, and the throttle valve 5 is reliably prevented from moving in the direction of the throttle shaft 3. , 5b are also arranged so as not to come into contact with the inner surface 2a of the bore 2 on the bearing side.

C. Effect of the invention As described above, according to the invention, the front and rear end surfaces 5a and 5b of the throttle valve 5 are connected to the bore 2.
Even if the throttle valve 5 is eccentric in the direction of the throttle shaft 3 so as to be in contact with the inner surface of the throttle valve 5, the front and rear end surfaces 5a, 5b and the left and right end surfaces 5c of the throttle valve 5 change from the fully open state to the fully closed state. , 5d will not come into contact with the inner peripheral surface of the bore 2. Therefore, as in the conventional case, the eccentricity of the throttle valve does not cause the throttle valve to be attracted to the inner peripheral surface of the bore within its operating range, resulting in poor performance of the governor, and stable engine performance is maintained. There are benefits to be gained.

[Brief explanation of the drawing]

FIG. 1 is a plan sectional view showing the first embodiment of the present invention;
2 is a plan view of the throttle valve, FIG. 3 is a sectional plan view showing a second embodiment of the present invention, FIG. 4 is a partially cutaway plan view of an air governor to which the present invention is applied, and FIG. 5 is a plan sectional view of the conventional structure, and FIG. 6 is a plan view of the same throttle valve. 2...Bore, 2a...Bearing side inner surface, 2b...
Inner surface, 3... Throttle shaft, 5... Throttle valve, 5a, 5b... Front and rear end surfaces, 5c, 5
d...Left and right end faces, 5e, 5f...Remaining end faces, 5
g, 5h...Remaining left and right peripheral surfaces, d...Gap.

Claims (1)

[Scope of utility model registration request] The bearing-side inner surface 2a of the throttle shaft 3 in the bore 2 is formed into a linear surface perpendicular to the axial direction of the throttle shaft 3, and the inner surface 2b of the bore 2 other than the bearing-side inner surface 2a is formed into a circular arc surface. In the case where the throttle valve 5 is provided in the bore 2, among the front and rear end surfaces of the throttle valve 5 facing the bearing-side inner surface 2a of the bore 2, the end surface 5a of the portion where the throttle shaft 3 is located; 5b is a linear surface that runs close to the bearing-side inner surface 2a, and the remaining end surfaces 5e and 5f other than the end surfaces 5a and 5b are arranged so that a predetermined gap d is created between them and the bearing-side inner surface 2a of the bore 2. It is formed by cutting inward from the end surfaces 5a and 5b, and further,
The left and right end surfaces 5c and 5d of the throttle valve 3, which are located on a line that passes through the center of the throttle valve 5 and is orthogonal to the throttle shaft 3, are connected to small holes that contact the inner peripheral surface of the bore 2 when the throttle valve 3 is fully closed. The remaining left and right circumferential surfaces 5g and 5h other than the left and right end surfaces 5c and 5d are formed in a circular arc surface in such a manner that a predetermined gap d is created between the inner surface of the bore 2 and the inner surface of the bore 2 when the throttle valve 3 is fully closed. , the left and right end surfaces 5c, 5d
A throttle valve for an air governor for an internal combustion engine, characterized by being formed into an arcuate surface with a smaller diameter.