JPS6243063B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a sliding throttle valve type carburetor.

In a sliding throttle valve type carburetor, the effective diameter of the intake passage can be varied by sliding a throttle valve arranged across the air supply passage formed in the carburetor body in the diametrical direction of the intake passage. The effective diameter of the fuel nozzle can be increased or decreased in accordance with the increase or decrease in the effective diameter of the intake passage by means of a tapered needle that moves together with the throttle valve.

In the conventional carburetor described above, since the needle moves together with the throttle valve, in order to obtain an appropriate rate of change in the effective diameter of the fuel nozzle with respect to the rate of change in the effective diameter of the intake passage, the needle moves in unison with the throttle valve. The tapered part of the carburetor became longer, which caused problems such as an increase in the height of the carburetor.

The inventor of the present application previously proposed in Japanese Patent Application No. 57-165104 to solve the above-mentioned problems by sliding the throttle valve and the needle with different strokes.

A further object of the present invention is to provide a sliding throttle valve type carburetor that allows variable fuel supply characteristics to an internal combustion engine.

The present invention includes a throttle valve that is slidably accommodated in a guide hole with both ends closed and intersecting the intake passage in order to vary the effective diameter of the intake passage provided in the carburetor body in the axial direction of the guide hole. , a fuel nozzle that opens into the intake passage from a wall surface portion of one closed end of the guide hole, and a fuel nozzle that is disposed along the axis of the guide hole and passing through the throttle valve, the other side of the guide hole being closed. A needle whose movement is guided along the axis of the guide hole in order to vary the effective diameter of the fuel nozzle by a guide portion provided on the end wall surface, and a needle which is oscillated by the operation of a throttle lever. an arm member operatively connected to the throttle valve to slide the throttle valve by dynamic motion; a cam surface provided on the arm member; a driven member that engages the needle and abuts the cam surface to move the needle in the movement direction of the throttle valve in conjunction with the swing movement of the arm member; By adjustablely positioning the swing shaft portion on the carburetor body, it is possible to select a change characteristic of the amount of fuel supplied from the fuel nozzle with respect to the opening degree of the throttle valve.

The features of the invention will become clearer from the following description of the illustrated embodiments.

The vaporizer 10 according to the present invention is shown in FIGS.
As shown in the figure, the intake passage 12 is open at both ends.
The carburetor body 14 includes a carburetor main body 14 in which an air intake passage 12 is formed, and a throttle valve 16 for making the effective diameter of the intake passage 12 variable.
The carburetor 10 is fixed to an internal combustion engine (not shown) by a flange portion 18 of the carburetor body so that one end of the intake passage 12 is connected to an air supply port of the engine (not shown). Although not shown, the other end of the intake passage 12 is connected to a conventionally well-known air cleaner.

The carburetor body 14 has a circular cross-sectional shape,
A guide hole 20 with both ends closed and intersecting the intake passage 12
is formed. In the illustrated example, the carburetor main body 14 includes a portion including a cylindrical portion 22 that defines a part of the guide hole in a plane crossing the axis of the guide hole 20, and a portion that includes a cylindrical portion 22 that defines a part of the guide hole, and a portion that cooperates with the cylindrical portion 22 to a closed-end tubular portion 24 coupled to the tubular portion 22 to define the bore 20;
It is divided into. The cylindrical portion 24 is connected to the carburetor main body excluding the cylindrical portion via a pair of mounting screws 26 (see FIG. 2), so that the mounting posture of the cylindrical portion 24 is set in the guide hole. Can be rotated 180 degrees in the circumferential direction.

The throttle valve 16 is made of a cylindrical member with one end closed. The throttle valve 16 has its closed end 16a connected to the intake passage 1.
one closed end 20 of the guide hole 20 adjacent to 2;
It is disposed in the guide hole 20 with its central axis aligned with the axial direction of the guide hole 20, facing the guide hole 20a. The throttle valve 16 is slidable in the axial direction of the guide hole to vary the effective diameter of the intake passage 12. The closed end 16a of the throttle valve 16 is configured to receive a nozzle tube 28 with both ends open, which extends from the wall surface portion of the one closed end 20a of the guide hole into the intake passage along the axis of the guide hole 20. hole 30
is formed. The nozzle tube 28 communicates at one end with a fuel passage 32 of a conventionally well-known fuel supply mechanism, and has a fuel nozzle 34 on its side for ejecting fuel.

A pivot shaft 36 parallel to the intake passage 12 is rotatably supported in the cylindrical portion 24 of the carburetor body 14, and a throttle lever 38 is attached to the projecting end of the pivot shaft.
is fixed. Further, an arm member 40 is fixed to the pivot 36. In the illustrated example, the arm member 40 has a boss portion 40a fixed to the pivot 36.
and a pair of arm portions 40b extending in parallel to each other from the boss toward the center of the guide hole 20, and the tip of each arm portion 40b is pivotally connected to the closed end 16a of the throttle valve 16. It is pivotally attached to the section 42 via a link member 44. Therefore, by operating the throttle lever 38, the arm member fixed to the pivot shaft 36 can be swung, thereby causing the arm member operatively connected to the arm member via the link member 44 to swing. Throttle valve 16
can be slid along the axis of the guide hole 20 between the illustrated idling opening position and a fully open position in which the intake passage 12 is fully opened. The throttle valve 16 is held at the above-mentioned idling opening position by the spring force of a conventionally well-known return spring 46 (see FIG. 2). In order to smoothly slide the throttle valve 16 by operating the throttle lever 38, the swarm member 40 and the throttle valve 1 are connected to each other.
It is preferable that the closed end 16a of the throttle valve 6 is made of an elastic synthetic resin material, and the elasticity of the parts made of the synthetic resin material can prevent looseness or play between the throttle lever and the throttle valve caused by assembly errors. This can be prevented by

A needle 48 is provided in the guide hole 20 for increasing or decreasing the effective diameter of the fuel nozzle 34 in accordance with the increase or decrease in the effective diameter of the intake passage due to the aforementioned sliding of the throttle valve 16.
is arranged along the axis of. Needle 4
In the example shown in FIG. 1, 8 includes a main body 50 having a uniform diameter in the axial direction, and a base 52 fixed to one end of the main body. A guide hole 56 is formed in the base 52 and is slidably fitted into a guide portion 54 extending from the wall surface of the other closed end 20b of the guide hole 20 along the axis of the guide hole 20.
The needle 48 has one end thereof, that is, the main body portion 5.
The sliding movement of the throttle valve 16 in the movement direction of the throttle valve 16, that is, in the axial direction of the guide hole 20, is guided by the guide portion so that the tip of the nozzle tube 28 is received at the other end of the nozzle tube 28. Further, the needle 48 receives a spring force toward the nozzle tube from a coil spring 58 disposed around the guide portion between the wall surface of the closed end 20b and the end surface of the base portion 52.

A bearing member 60 is provided near the guide portion 54 in the guide hole 20 and is positioned in the cylindrical portion 24 so as to be adjustable in the diametrical direction of the guide hole 20 and in the axial direction thereof. A driven member 62 is swingably supported.

In the example shown in FIG. 1, the bearing member 60 is disposed outside the cylindrical portion 24 of the carburetor body 14 in the diametrical direction of the guide hole 20, and is arranged in the diametrical direction of the guide hole 20.
a first adjustment screw 66 that is screwed into the screw hole 64 of the
One side portion 70a in which a hole 68 is formed to allow the shaft portion 66a of the adjustment screw to pass through, and the other side portion 70 extending at right angles to the one side portion and in the diametrical direction of the guide hole 20.
an L-shaped base member 70 having a diameter of A second adjustment screw 76 having a portion 76a is supported on the carburetor body by a positioning mechanism.

One side 70a of the base member 70 is connected to the head 66b of the first adjusting screw by the spring force of a coil spring 78 disposed around the shaft 66a of the first adjusting screw. is held between. Therefore, the first adjustment screw 66
By rotating the base member 70, the base member 70 can be moved in the diametrical direction of the guide hole 20, and the base member 70 can be positioned at that position.

The second adjusting screw 76 has its top portion 77b locked to the other side portion 70b of the base member, and its shaft portion 76a extends into the guide hole 20 in parallel with the axis of the guide hole 20. The hole 72 formed in the other side 70b of the base member receives the shaft portion 76a of the adjustment screw 76 so as to move the adjustment screw 76 in parallel with the movement of the base member 70, and the adjustment screw 76 is attached to the base member 70. It is rotatable relative to member 70. Further, the hole 74 formed at the top of the cylindrical portion 24 receives the shaft portion 76a of the second adjusting screw 76 so as to allow the parallel movement of the screw. The bearing member 64 is screwed onto the shaft portion 76a near the closed end 20b. Therefore, while the bearing member 64 is prevented from rotating relative to the adjustment screw 76, the second adjustment screw 76 is
By rotating the bearing member 64, the bearing member 64 can be moved in the axial direction of the guide hole, and the bearing member 64 can be positioned at that position.

In the example shown in FIG. 2, the driven member 62 includes a swing shaft portion 62a supported by the bearing member 64, and a swing shaft portion 62a that extends from both ends of the swing shaft portion toward the boss portion 40a of the arm member. The tip of each arm member 62b is a U-shaped link member having a pair of arm portions 62b extending in parallel, and the tip of each arm member 62b returns to a bent portion 62c.
slidingly abuts on the upper surface 80 of each arm portion 40b. Since the pair of arm portions 62b extend on both sides of the needle base 52, the bearing member 60 supporting the driven member 62 is prevented from rotating relative to the second adjustment screw 76 by the needle 48. There is. In addition, each arm portion 62
b is bent into a valley shape and engages with the lower surface of a pair of protrusions 82 provided on the base 52 of the needle 48.

In the carburetor 10 according to the present invention, the throttle lever 3
8 is rotated, for example, in the counterclockwise direction as seen in FIG.
The upper surface 80 of each arm portion 40b of 0 is the bent portion 6
2c acts as a cam surface. This cam surface 80 is attached to the driven member 62 as the arm member swings.
is swung around its swiveling shaft portion 62a.
The swinging of the driven member 62 causes the needle 48 to slide in its axial direction, that is, in the axial direction of the guide hole 20, so that the needle 48 moves inside the nozzle tube 28 according to an increase or decrease in the effective diameter of the intake passage 20. This causes the effective diameter of the fuel nozzle 34 to increase or decrease.

The effective aperture of the fuel nozzle 34, that is, the change characteristic of the fuel supply amount in relation to the change in the effective aperture of the intake passage 20, that is, the opening degree of the throttle valve 16, can be controlled by the operation of the adjusting screws 66, 76, such as the engine or its operating environment, etc. It can be adjusted as appropriate.

3 and 4 are graphs showing the opening degree of the throttle valve 16 and the fuel supply amount on the X-axis and Y-axis, respectively. When the first adjusting screw 66 is rotated at the idling opening degree shown in FIG. 1, the driven member 62 holds the needle 48 in a substantially predetermined position without causing the needle 48 to slide significantly in the axial direction of the needle. The bearing member 66 in the held state
At the same time, the arm portion 62b moves in the longitudinal direction along the diameter direction of the guide hole 20. Therefore, by adjusting the first adjusting screw 66, the position of the needle 48 at the idling opening does not change, and the fuel supply amount at this idling opening does not change, but the driven member 62 Since the distance from the swing shaft 62a to the protrusion 82 of the needle 48 changes, the rate of movement of the nozzle 48 in the medium speed range exceeding the idling opening, that is, the rate of increase/decrease in the supplied fuel changes. Therefore,
By adjusting the first adjusting screw 66, as shown in FIG. 3, the fuel supply characteristics in the medium speed range, that is, in the partial load range can be changed within the shaded area of the graph in FIG. .

When the second adjustment screw 76 is rotated at the idling opening shown in FIG.
Since the driven member 62 swings around the bent portion 62c as the driven member moves up and down, the needle jet 48 moves in its axial direction as the driven member swings. Therefore, by adjusting the second adjusting screw 76, the idling opening degree and the fuel supply characteristics in the vicinity thereof can be changed within the shaded area of the graph, as shown in FIG.

Therefore, according to the carburetor, appropriate fuel supply characteristics can be obtained by adjusting the adjusting screws 66 and 76, or either one thereof, depending on the type of front engine or the operating environment of the engine. This makes it possible to maintain and control the operation of the engine well.

Furthermore, in the carburetor 10, the needle 48 slides due to the swinging of the driven member 62 that comes into contact with the cam surface 80 of the arm member. is smoothly transmitted to the needle. Therefore, when the effective diameter of the intake passage is increased or decreased by operating the throttle lever 38, the needle jet can be smoothly slid in accordance with the sliding movement of the throttle valve. Since the effective diameter of the fuel nozzle 34, that is, the fuel supply amount can be quickly and appropriately increased or decreased in accordance with the increase or decrease in the opening degree, the responsiveness of the engine to the operation of the throttle lever 38 can be improved.

In the above description, an example was described in which a needle without a tapered tip was used and a nozzle tube was provided with a fuel nozzle on the side. The open end of the nozzle tube, which is open to the intake passage, can be used as the fuel nozzle without providing a fuel nozzle on the side of the nozzle tube. Furthermore, although an example has been described in which the swing shaft portion of the driven member is adjustable in the axial direction and diametrical direction of the guide hole, the swing shaft portion may be positioned in either the axial direction or the diametric direction of the guide hole. It will be clear that the fuel delivery characteristics can also be made variable by adjustable positioning in the direction.

According to the present invention, as described above, the movement of the arm member operatively connected to the throttle valve and swung by the operation of the throttle lever transfers the fuel via the driven member that comes into contact with the cam surface of the arm member. The information is transmitted to the needle for making the effective aperture of the nozzle variable, and the swing shaft of the driven member is adjustable, so that by adjusting the position of the swing shaft, the aperture can be adjusted. It is possible to adjust the change characteristic of the fuel supply amount with respect to the change in the opening degree of the valve to the characteristic most suitable for the operation of the engine. Therefore, the operation of the engine can be maintained and controlled appropriately, and the operational performance of the engine can be improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a vaporizer according to the present invention, FIG. 2 is a sectional view taken along the line - shown in FIG. 1, and FIGS. 3 is a graph showing fuel supply characteristics of the carburetor according to FIG. 12: Air supply path, 14 (22, 24): Carburetor body, 16: Throttle valve, 20: Guide hole, 20a, 20
b: closed end, 34: fuel nozzle, 38: throttle lever, 40: arm member, 48: needle,
60: bearing member, 62: driven member, 62a: swing shaft portion, 80: cam surface.

Claims (1)

[Scope of Claims] 1. A carburetor that is slidably housed in a guide hole with both ends closed and intersecting the intake passage in the axial direction of the guide hole in order to vary the effective diameter of the intake passage provided in the carburetor body. a throttle valve; a fuel nozzle that opens into the intake passage from a wall portion of one closed end of the guide hole; A needle whose movement is guided along the axis of the guide hole in order to vary the effective diameter of the fuel nozzle by a guide portion provided on the wall surface portion of the other closed end, and a needle which is oscillated by operation of a throttle lever. an arm member operatively connected to the throttle valve so as to slide the throttle valve by its swinging motion; and a cam surface provided on the arm member, the arm member being swingable in the vicinity of the other closed end. a driven member having a swinging shaft supported by the arm member, the driven member engaging the needle and abutting the cam surface to move the needle in the movement direction of the throttle valve in conjunction with the swinging movement of the arm member; A sliding throttle valve type carburetor, comprising: a sliding throttle valve member, wherein the swing shaft portion is adjustable in position on the carburetor body. 2. The sliding throttle valve type carburetor according to claim 1, wherein the swing shaft portion is positioned so as to be adjustable in the diametrical direction of the guide hole. 3. The sliding throttle valve type carburetor according to claim 1, wherein the swing shaft portion is positioned so as to be adjustable in the axial direction of the guide hole. 4. The sliding device according to claim 1, wherein the swing shaft is supported by the carburetor main body via a bearing member that is adjustable in the diametrical direction of the guide hole and in the axial direction. Throttle valve type vaporizer.