JP2012067770A - Rotary type carburetor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To arrange a cam mechanism for moving a throttle valve in the valve stem direction without enlarging a carburetor body, in a rotary type carburetor.SOLUTION: This rotary type carburetor includes a columnar throttle valve 7, a fuel nozzle 8 arranged on its axis and inserting a weighing needle 4, and the cam mechanism for moving the throttle valve 7 in the valve stem direction, and adjusts an air flow rate and a fuel flow rate by moving in the valve stem direction by the cam mechanism while rotating the throttle valve 7 by rotating a valve stem 5 in response to throttle operation. The cam mechanism is constituted of a cam surface 71a formed along its rotational direction in an outer peripheral side predetermined range of a bottom surface of the throttle valve 7, and a support pin 9 inserted and arranged between a bottom surface of a columnar throttle valve chest 11 of rotatably inserting and arranging the throttle valve 7 and the cam surface 71a, supporting the throttle valve 7 from the bottom surface side and arranging the axis in the orthogonal direction to the axis of the throttle valve 7.

Description

  The present invention relates to a rotary carburetor provided with a cam mechanism for moving a throttle valve in a valve shaft direction.

  Rotary vaporizer (rotary throttle) equipped with a cam mechanism for moving the throttle valve (throttle valve) in the direction of the valve shaft as a device for supplying vaporized fuel to engines such as portable working machines and small vehicles for agriculture and forestry Valve carburetors) are widely used. In this rotary type carburetor, a cylindrical throttle valve having a throttle valve hole and a metering needle is arranged orthogonal to the intake passage of the carburetor body, and the valve is rotated while the throttle valve is rotated according to the accelerator operation. By moving in the axial direction, the air flow rate is controlled while changing the degree of overlap of the throttle valve hole with the intake passage, and the fuel flow rate is controlled by changing the insertion depth of the metering needle into the fuel nozzle. ing.

  A cam mechanism is used as means for moving the throttle valve in the valve shaft direction. As this cam mechanism, as shown in, for example, Japanese Utility Model Laid-Open No. 58-92447 and shown in the partial longitudinal sectional view of FIG. There is known a carburetor in which an end face cam 58 having an inclined surface is provided and a driven pin 59 is projected from the lower surface of a throttle lever 57.

  Further, as shown in, for example, Japanese Patent Application Laid-Open No. 6-129303 and shown in the partial vertical sectional view of FIG. 5B, a driven pin 60 is provided to protrude from the bottom surface of the throttle valve 52 and the bottom surface of the throttle valve hole 55 is provided. There are also known carburetors with end cams 61 projecting from them, or carburetors with these arranged in the opposite direction.

  The former in which the cam mechanism is provided outside the carburetor main body as in the former vaporizer has an advantage that the carburetor main body can be installed without increasing the size as compared with the case in which the cam mechanism is provided inside. However, since the cam mechanism is exposed to the outside, dust or dirt adheres to this portion, which tends to cause malfunction and unstable fuel flow rate.

  On the other hand, in the case where the cam mechanism is provided inside the carburetor body like the latter carburetor, there is no fear of occurrence of trouble due to adhesion of dust or the like from the outside. However, since it is necessary to secure a space for installing the driven pin having the vertical center axis constituting the cam mechanism on the bottom surface of the throttle valve or the bottom surface of the throttle valve hole inside the carburetor body, In particular, when a large throttle valve is used for a large displacement engine, it is not suitable because the carburetor body needs to be further enlarged.

Japanese Utility Model Publication No. 58-92447 JP-A-6-129303

  The present invention is intended to solve the above-described problems, and a cam mechanism for moving a throttle valve in the valve shaft direction can be arranged in a rotary carburetor without enlarging the carburetor body. The challenge is to do so.

  Therefore, the present invention provides a cylindrical throttle valve that is arranged perpendicular to the intake passage of the carburetor body and has a throttle hole and a metering needle, and a metering needle that is arranged on the central axis of the throttle valve. A fuel nozzle and a cam mechanism for moving the throttle valve in the valve shaft direction, and the throttle valve is rotated by rotating a valve shaft extending from the center of the upper surface of the throttle valve according to a throttle operation. In a rotary carburetor that adjusts an air flow rate and a fuel flow rate by moving in the valve shaft direction by the cam mechanism while rotating integrally with the valve shaft, the cam mechanism is an outer peripheral edge of the bottom surface of the throttle valve. Between the cam surface and a cam surface formed along the rotation direction with a predetermined width in the central axis direction and a bottom surface of a cylindrical throttle valve chamber in which the throttle valve is rotatably inserted. A cylindrical support pin having a central axis arranged in a direction perpendicular to the central axis of the throttle valve for supporting the throttle valve from the bottom side with the portion abutting against the cam surface, and the throttle valve when the throttle is fully closed The bottom surface of the throttle valve can be substantially in close contact with the bottom surface of the throttle valve chamber by being supported with the support pin in contact with the cam surface portion formed on the bottom surface of the throttle valve when It is characterized by being.

  In particular, in the present invention, the cam surface forming the cam mechanism is formed to be recessed from the outer peripheral edge of the bottom surface of the throttle valve so as to gradually deepen along the rotation direction with a predetermined width in the central axis direction. The cam groove is a portion inserted into the cam groove from the side of the throttle valve chamber between the bottom surface of the cylindrical throttle valve chamber in which the throttle valve is rotatably inserted and the cam surface. A cylindrical support pin having a direction perpendicular to the central axis of the throttle valve that supports the throttle valve from the bottom surface side in contact with the surface, and when the throttle valve is at the lowest position when the throttle is fully closed The bottom surface of the throttle valve is supported on the bottom surface of the throttle valve chamber by supporting the support pin in contact with the cam surface portion that is the deepest portion of the cam groove formed on the bottom surface of the throttle valve. It is possible to contact.

  Further, in the present invention, by inserting a part of the cylindrical support pin into the bottom surface of the throttle valve chamber, when the throttle valve is at the lowest position when the throttle is fully closed, The bottom surface of the throttle valve can be easily and substantially adhered to the bottom surface of the throttle valve chamber by being supported with the support pin in contact with the cam surface portion that is the deepest portion of the formed cam groove.

  Further, in the rotary carburetor described above, the cam groove is formed with a predetermined width in the central axis direction from the outer peripheral side edge of the bottom surface of the throttle valve, and the support pin of the cam mechanism is oriented in a direction perpendicular to the central axis of the throttle valve. If it is inserted from the side, assembly work becomes relatively easy.

  Furthermore, in the rotary type carburetor described above, the portion of the support pin that contacts the cam surface is a support roller that rotates following the rotation of the throttle valve. The wear at the contact portion between the support pin and the throttle valve can be minimized.

  According to the present invention in which the cam surface of the cam mechanism is provided on the bottom surface of the throttle valve, the cam mechanism for moving the throttle valve in the valve shaft direction can be arranged without increasing the size of the carburetor body.

It is a fragmentary longitudinal cross-sectional view of the rotary vaporizer | carburetor of embodiment in this invention. FIG. 2 is a partial longitudinal sectional view when the throttle valve of the rotary type carburetor of FIG. 1 is rotated to a fully open state. It is a perspective view of the throttle valve of the rotary carburetor of FIG. It is a front view which shows the structure of the cam mechanism by the throttle valve and support pin of FIG. (A) is a partial longitudinal cross-sectional view which shows a prior art example, (B) is a partial longitudinal cross-sectional view which shows another prior art example.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a partial longitudinal sectional view centering on an intake passage 10 of a rotary carburetor according to the present embodiment. In particular, the cam surface of the cam mechanism is formed by a cam groove provided on the bottom surface of a throttle valve. In this case, a cylindrical throttle valve 7 in which a valve shaft 5 having a throttle lever 3 is connected to the base end side is provided in an intake passage 10 of the carburetor body 1. The throttle valve chamber 11 is orthogonally formed in a cylindrical shape and is rotatably inserted around its central axis.

  A throttle valve hole 70 passes through the throttle valve 7 from the side at right angles to the central axis, and the tip side of the metering needle 4 inserted into the throttle valve hole 5a passing through the valve shaft 3 is the throttle valve hole. While inserting into the fuel nozzle 8 extending from the bottom surface of the throttle valve chamber 11 and extending through the bottom surface of the throttle valve 7 and extending to the center position of the throttle valve hole 70 while projecting into the valve 70, the insertion depth is varied. Thus, the fuel flow rate is changed by changing the degree of opening of the fuel port 80 opened on the side surface of the front end side of the fuel nozzle 8.

  The throttle valve 7 is disposed in a state in which a valve spring 6 is interposed between a base end side surface of the throttle valve 7 and an inner side surface of the cover body 2 that closes the opening of the throttle valve chamber 11. The lever 3 is rotated to move in the valve shaft direction by the operation of a cam mechanism described in detail below while rotating in the throttle valve chamber 11, thereby adjusting the air flow rate and the fuel flow rate.

  That is, when the cam mechanism is provided inside the carburetor body, as shown in FIG. 5B, in the conventional example, the end face cam formed with the cam surface is provided protruding from the bottom surface of the throttle valve or the throttle valve chamber. Therefore, there is a problem that the length of the throttle valve chamber in the direction of the valve shaft is increased and the size of the carburetor main body is increased accordingly.

  On the other hand, in the rotary type carburetor of the present invention, the cam groove 71 is formed with the cam surface 71a inclined so as to gradually become deeper along the rotation direction in a predetermined range on the outer peripheral side of the bottom surface 21b of the throttle valve 7. A cylindrical shape that supports the throttle valve 7 from the bottom surface side between a bottom surface 11a of a cylindrical throttle valve chamber 11 in which the throttle valve 7 is rotatably inserted and a cam surface 71a of the throttle valve 7. The cam mechanism is configured by combination with the support pin 9.

  The cam groove 71 is formed with a predetermined width in the central axis direction from the outer peripheral edge of the bottom surface 71 b of the throttle valve 7, and the cylindrical support pin 9 is oriented in a direction perpendicular to the central axis of the throttle valve 7. A portion that is inserted from the side and abuts against the cam surface 71 a is a support roller 91 that rotates following the rotation of the throttle valve 7, and a contact portion between the support pin 9 and the throttle valve 7. Wear is minimized.

FIG. 1 shows a throttle fully closed state of the rotary type carburetor, and the throttle valve 7 is at the lowest position and the cam surface 71a portion which is the deepest portion of the cam groove 71 formed in the bottom surface 71b. The support pin 9 is in contact with the bottom surface 71 of the throttle valve 7.
“b” is a position in close contact with the bottom surface 11 a of the throttle valve chamber 11.

  Then, by turning the throttle lever 3 and turning the throttle valve 7, the throttle is fully opened as shown in FIG. In this case, as the throttle valve 7 rotates from the state of FIG. 1, the contact position of the support pin 9 with respect to the inclined cam surface 71a becomes shallower (substantially the bottom surface position), the throttle valve 7 compresses the valve spring 6. While raising in the direction of the arrow, the inner peripheral surface of the throttle valve hole 70 coincides with the inner peripheral surface of the intake passage 10, and the metering needle 4 is lifted so that the fuel port 80 of the fuel nozzle 8 is also fully opened.

  Thus, by rotating the throttle lever 3, the throttle valve 7 moves in the valve shaft direction in conjunction with the rotation of the throttle valve 7 in the throttle valve chamber 11 by the cam mechanism. Is adjusted at the same time as the fuel flow rate. In this case, the throttle valve 7 is in the uppermost position when the throttle is fully opened, and the throttle valve 7 is in the lowest position when the throttle valve is fully closed. Therefore, the adjustment of the air flow rate and the fuel flow rate can be easily performed with simple operations.

  A cam mechanism for moving the throttle valve 7 in the valve shaft direction is formed by a cam surface 71 formed by a cam groove 71 formed on the bottom surface 71b of the throttle valve 7 and a bottom surface 11a of the throttle valve chamber 11 so as to be in contact with the cam surface 71. By comprising the support pin 9 inserted between them, the enlargement of the length of the throttle valve chamber 11 in the valve shaft direction is avoided and the enlargement of the carburetor body 1 is minimized. It is a thing. In particular, in the present embodiment, since the insertion groove 11b of the support pin 9 is formed on the bottom surface 11a of the throttle valve chamber 11, the bottom surface 11a of the throttle valve chamber and the bottom surface 71b of the throttle valve 7 can be brought into close contact with each other. .

  Further, in this cam mechanism, the support pin 9 is inserted from the side in a direction perpendicular to the central axis of the throttle valve 7, and the assembly work is performed because the throttle valve 7 is inserted from above. It is relatively easy. Furthermore, since the support pin 9 supports the throttle valve 7 in a state where it is in contact with the cam surface 71a by the support roller 91 on the front end side, it is possible to minimize wear of the contact portion. Yes.

  As described above, the rotary carburetor can be provided with a cam mechanism for moving the throttle valve in the valve shaft direction without increasing the size of the carburetor body according to the present invention.

1 carburetor body, 2 cover body, 3 throttle lever, 4 metering needle, 5 valve shaft, 5a
Throttle through hole, 6 valve spring, 7 throttle valve, 8 fuel nozzle, 9 support pin, 10 intake passage, 11 throttle valve chamber, 11a bottom surface, 11b fitting groove, 70 throttle valve hole, 71 cam groove, 71a cam surface, 80 Fuel port, 91 Support roller

Claims (3)

  A cylindrical throttle valve that is disposed perpendicular to the intake passage of the carburetor body and has a throttle hole and a metering needle; a fuel nozzle that is disposed on the central axis of the throttle valve and into which the metering needle is inserted; And a cam mechanism for moving the throttle valve in the valve shaft direction, and the throttle valve is integrated with the valve shaft by rotating the valve shaft extending from the center of the upper surface of the throttle valve according to the throttle operation. In the rotary type carburetor that adjusts the air flow rate and the fuel flow rate by moving in the valve axis direction by the cam mechanism while rotating in the direction, the cam mechanism has a predetermined width in the central axis direction from the outer peripheral edge of the bottom surface of the throttle valve. The cam surface is formed between the cam surface formed along the rotation direction and the bottom surface of the cylindrical throttle valve chamber in which the throttle valve is rotatably inserted and the cam surface. It comprises a cylindrical support pin with a central axis arranged in a direction perpendicular to the central axis of the throttle valve that abuts and supports the throttle valve from the bottom side, and the throttle valve is at the lowest position when the throttle is fully closed The support pin is in contact with a cam surface portion formed on the bottom surface of the throttle valve so that the bottom surface of the throttle valve can be substantially in close contact with the bottom surface of the throttle valve chamber. Characteristic rotary vaporizer.   The cam surface forming the cam mechanism is a cam groove formed by being recessed from the outer peripheral side edge of the throttle valve bottom surface so as to gradually become deeper along the rotation direction with a predetermined width in the central axis direction, A portion inserted into the cam groove from the side of the throttle valve chamber is brought into contact with the cam surface between the bottom surface of the cylindrical throttle valve chamber in which the throttle valve is rotatably inserted and the cam surface. A cylindrical support pin having a central axis arranged in a direction orthogonal to the central axis of the throttle valve that supports the throttle valve from the bottom surface side, and the throttle valve is in the lowest position when the throttle is fully closed. The support pin is supported in contact with the cam surface portion, which is the deepest portion of the cam groove formed on the bottom surface of the valve, so that the bottom surface of the throttle valve is substantially in close contact with the bottom surface of the throttle valve chamber. Rotary evaporator, characterized in that it is possible.   The rotary type carburetor according to claim 1 or 2, further comprising an insertion groove into which at least a part of the cylindrical support pin is inserted into a bottom surface of the throttle valve chamber.

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