JP2863783B2 - Sliding throttle valve carburetor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention regulates the amount and concentration of air-fuel mixture supplied to an engine,
The present invention relates to a carburetor to be controlled, and particularly to a sliding throttle valve carburetor in which a throttle valve is movably disposed in a throttle valve guide cylinder connected to an intake passage, and is often used as a carburetor for a motorcycle engine. [Prior Art] Conventionally, as described above, a sliding throttle valve type carburetor is often used for a motorcycle, and therefore, it is important that the intake air supplied to an engine is made particularly efficiently. Therefore, it is desired that the groove remaining on the side of the intake path of the throttle valve guide cylinder for guiding and holding the sliding throttle valve is as small as possible. For example, Japanese Utility Model Application No. 60-47860 filed by the present applicant. There are technologies such as According to this, the sliding throttle valve comprises a flat valve portion and a protrusion from the flat valve portion to the air cleaner side, and a jet needle is attached to the protrusion. When the dynamic throttle valve is fully opened, only a thin rectangular groove corresponding to a flat valve portion remains on the side of the intake passage, so that the resistance of the groove to the airflow flowing through the intake passage can be minimized. It is possible to improve the air suction efficiency. [Problems to be Solved by the Invention] However, although the above-mentioned suction efficiency can be improved, the portion where the jet needle is attached is disposed on the projection provided on the air cleaner side from the flat valve portion. Therefore, the intake passage is farther from the flattened valve portion that can be most narrowed. According to this, air flows from the periphery of the projection to the vicinity of the jet needle, and it is difficult to sufficiently increase the negative pressure applied to the jet needle and the needle jet into which the jet needle is inserted, which hinders atomization of fuel. However, improvement in the atomization characteristics of the fuel with respect to opening of the sliding throttle valve cannot be expected. On the other hand, if the jet needle is placed on the flat valve, the jet needle is located at the narrowest part of the intake path, so the atomization characteristics of the fuel are improved, but the thickness of the flat valve increases. According to this, the groove portion corresponding to the flat valve portion becomes large, and resistance to the air flow flowing through the intake passage becomes caused, thereby lowering the suction efficiency. [Means for Solving the Problems] The sliding throttle valve type carburetor according to the present invention has been made in view of the above problems, has a high suction efficiency, and further increases the negative pressure applied to the jet needle and the needle jet to increase the fuel. It is an object of the present invention to provide a vaporizer having good atomization characteristics and to achieve the above object. That is, the sliding throttle valve is constituted by the engine-side facing side and the air cleaner-side facing side, the engine-side facing side is formed in an arc shape, and the arc-shaped end of the engine-side facing side and the air cleaner-side facing side are formed. Each end is connected by a guide side surface substantially along the longitudinal axis of the intake path, and a cutterway is provided at the bottom of the sliding throttle valve from the air cleaner side to the engine side to the engine side. The center of the jet needle disposed on the throttle valve is connected to the end of the side surface facing the air cleaner, and the jet needle is disposed closer to the engine than a line perpendicular to the longitudinal axis of the intake passage. [Operation] The jet needle can be arranged at the throttled portion of the sliding throttle valve, and does not allow air flow from around the side of the jet needle, so that the negative pressure applied to the jet needle and the needle jet can be increased, and the sliding can be performed. Since the groove for slidingly guiding the throttle valve to the carburetor body can be held substantially equal to that of the flat throttle valve portion, the suction efficiency does not decrease. [Embodiment] An embodiment of a sliding throttle valve type carburetor according to the present invention will be described below with reference to FIGS. 1 is a carburetor body through which an intake passage 2 penetrates,
The throttle valve guide guide cylinder 3 connected to the intake passage 2 is opened, while a float chamber 5 is formed by the lower recess of the carburetor body 1 and the float chamber body 4. A float F is disposed in the float chamber 5, and the float F operates a valve seat disposed at an end of a fuel inflow path (not shown) and a float valve for opening and closing the valve seat. The liquid level is formed and maintained. Reference numeral 6 denotes a sliding throttle valve, which will be described in more detail with reference to FIG. The sliding throttle valve 6 is formed by an engine-side facing side surface 6A (the right side in the figure) facing the engine side and an air cleaner-side facing side surface 6B facing the air cleaner side. This engine side facing side 6A
Are formed in an arc shape (semicircular shape with a single radius R). From the arcuate ends A and B of the engine-side facing side surface 6A, guide side surfaces 6C and 6C are provided substantially along the longitudinal axis XX of the intake passage 2, respectively. The air cleaner side facing side surface 6B is formed from the ends C and D (the side opposite to the engine side facing side surface 6A). (Note that the width H of the guide side surfaces 6C, 6C is preferably a slight width of about 3 mm.) Further, the air cleaner side facing side surface 6B will be described in detail. From the other end portions C and D of the guide side surfaces 6C and 6C, a straight line portion 6D, 6D substantially perpendicular to the longitudinal axis XX of the intake passage 2 and the longitudinal axis XX of the intake passage 2 are formed. Straddle and the straight section
6D, the air cleaner side from 6D (left side in Fig. 3)
It is connected by the protruding connecting portion 6E. Further, at the bottom of the sliding throttle valve 6, which opens into the intake passage 2, a cutter 6F for controlling the intake passage negative pressure acting on the needle jet, which will be described later, is provided. An inclined surface is formed from the side surface 6B toward the engine-side facing side surface 6A. Then, the longitudinal axis X of the intake passage 2 of the sliding throttle valve 6 is set.
On X, the center K of the jet needle 7 is arranged on the engine side (the right side in FIG. 3) from the line CD connecting the ends C and D of the side surface 6B facing the air cleaner. More specifically, the center of the jet needle insertion hole 6G for inserting and holding the jet needle 7 may be disposed on the line CD or on the engine side of the line CD. Reference numeral 8 denotes a needle jet opened to the intake passage 2, and this needle jet 8 is immersed below a certain liquid level of the float chamber 5 via the nozzle 9 and the main fuel jet 10. According to the sliding throttle valve type carburetor having the above configuration, the sliding throttle valve 6 opens and closes the intake passage 2 by operating the operation wire W, thereby controlling the gap between the jet needle 7 and the needle jet 8. In particular, according to the sliding throttle valve 6 according to the present invention, since the engine-side facing side surface 6A of the sliding throttle valve 6 is formed in an arc shape, the sliding throttle valve 6 is disposed on the engine-side intake passage. When the sliding throttle valve 6 is sucked to the engine side by the generated negative pressure, the distribution load of the pressing force against the engine-side guide cylinder surface of the engine-side facing side surface 6A of the sliding throttle valve 6 is reduced by the conventional flat sliding. Since it was smaller than the throttle valve, the durable wear of that portion was improved. In addition, since the jet needle 7 can be arranged at the throttle portion of the drive throttle valve 6, and the inflow of air from the periphery thereof, particularly the upper and lower side portions in FIG. 2, can be prevented, the negative pressure generated in the jet needle 7 and the needle jet 8 can be prevented. Can be enhanced. Further, since the guide groove portion G remaining in the intake passage 2 when the sliding throttle valve 6 is fully opened is formed by a relatively small groove, a large amount of fully opened intake air can be sucked. Further, since the play of the sliding throttle valve 6 in the direction perpendicular to the longitudinal axis XX of the intake path 2 of the sliding throttle valve 6 can be performed at the guide side surface 6C provided on the sliding throttle valve 6, The fall of the valve 6 can be suppressed as much as possible, and the gap error caused by the fall between the jet needle 7 and the needle jet 8 can be controlled. [Effects of the Invention] As described above, the sliding throttle valve carburetor according to the present invention has the following effects. Since the jet needle could be arranged on the engine-side sliding throttle valve including the line connecting the arc-shaped ends of the engine-side facing side surface, the air flow to the jet needle and the needle jet was all along the longitudinal axis of the intake path. Since it flows from the center line direction, the intake negative pressure for them can be made larger than that of the conventional one. According to this, the atomization characteristics of the fuel are improved and the engine with respect to the opening of the sliding throttle valve is improved. The response is improved. The groove of the guide part of the sliding throttle valve to the carburetor body was made almost equal to that of the plate-shaped guide groove of the plate-shaped sliding throttle valve, thereby improving the suction efficiency of the engine. , And the output can be improved. Since the engine-side facing side of the sliding throttle valve is formed in an arc shape, the area of the guide portion to the carburetor body can be made larger than that of the plate-shaped sliding throttle valve, and the pressing load (unit area) of the sliding portion can be increased. Per contact) was reduced, so that a sliding throttle valve carburetor with less wear of the sliding throttle valve for a long period of time and less leakage from the sliding throttle valve to the engine-side intake passage could be provided. is there.
In addition, since the engine-side facing side of the sliding throttle valve is formed into a circular arc with a single circle, the area of the guide portion to the carburetor body can be made larger than that of the plate-shaped sliding throttle valve. Since the pressing load (per unit area) of the part has been reduced, the sliding throttle valve has little wear over a long period of time, and the sliding throttle valve type vaporizer has little leakage from the sliding throttle valve to the engine-side intake passage. Vessel can be provided. Further, the groove of the guide portion of the sliding throttle valve to the carburetor body can be made substantially equal to the plate-shaped guide groove of the plate-shaped sliding throttle valve, and according to this, the suction efficiency of the engine is improved. Was successfully maintained, and the output could be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view showing one embodiment of a sliding throttle valve type carburetor according to the present invention, FIG. 2 is an upper plan view showing a state where an upper lid is removed in FIG. FIG. 3 is a detailed explanatory view of the sliding throttle valve used in FIG. 6… Sliding throttle valve, 6A… Engine side facing side, 6B… Air cleaner side facing side, 6C… Guide side face, 6D …… Linear part, 6E …… Connection part, 6F …… Cutter way, K… ... the center of the jet needle,

Claims (1)

(57) [Claims] A throttle valve guide cylinder is connected to an intake path passing through the carburetor body, and a slide throttle valve having a jet needle disposed at the bottom is slidably disposed in the throttle valve guide cylinder. The sliding throttle valve 6 comprises an engine-side facing side surface 6A and an air cleaner-side facing side surface 6B, the engine-side facing side has an arc shape, and the arc-shaped ends A, B of the engine-side facing side surface. And ends C and D of the side face 6B facing the air cleaner.
Are connected by guide side surfaces 6C substantially along the longitudinal axis XX of the intake passage 2, and the bottom side of the sliding throttle valve 6 is opposed to the engine cleaner side surface 6B by the air cleaner side surface 6B.
A cutting way 6F heading to 6A is provided.
The center K of the jet needle 7 is connected to the ends C and D of the side surface 6B on the air cleaner side, and is disposed closer to the engine than a line CD perpendicular to the longitudinal axis XX of the intake passage 2. A sliding throttle valve carburetor. 2. A throttle valve guide cylinder is connected to an intake path passing through the carburetor body, and a slide throttle valve having a jet needle disposed at the bottom is slidably disposed in the throttle valve guide cylinder. The sliding throttle valve 6 comprises an engine-side facing side surface 6A and an air cleaner-side facing side surface 6B, the engine-side facing side has an arc shape, and the arc-shaped ends A, B of the engine-side facing side surface. And ends C and D of the side face 6B facing the air cleaner.
Are connected by guide side surfaces 6C substantially along the longitudinal axis XX of the intake passage 2, and the bottom side of the sliding throttle valve 6 is opposed to the engine cleaner side surface 6B by the air cleaner side surface 6B.
A cutterway 6F is provided toward 6A, and the air cleaner-side facing side surface 6B is further provided with straight portions 6D that are substantially perpendicular to the longitudinal axis XX of the intake passage 2 from the ends C and D of the facing side surfaces. 6D, a connecting portion 6E connecting the linear portions 6D, 6D and projecting toward the air cleaner side from the linear portions 6D, 6D.
The center K of the jet needle 7 arranged on the sliding throttle valve 6 connects the ends C and D of the side surface 6B facing the air cleaner and is orthogonal to the longitudinal axis XX of the intake passage 2. A sliding throttle valve type carburetor arranged on the engine side with respect to line CD.