JP2005120858A - Fuel adjusting device for carburetor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel adjusting device wherein a cap for restricting readjustment of a regulating valve that changes the effective area of a fuel passage can not be intentionally removed nor damaged. <P>SOLUTION: A head part 15 of the regulating valve 11 protrudes inside a fitting hole 5 so that the cap 21 is completely set inside the fitting hole 5 and can not be removed nor damaged when attached on the head part 15. An arm piece 27 protruding forward in an area within the outer diameter of the cap 21 contacts a stopper 6 disposed on a deep section circumferential surface of the fitting hole 5 to restrict a readjustment range. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a manual fuel adjustment device provided in a carburetor that supplies fuel to a general-purpose engine used as a power source of a portable work machine or the like.

  Since the carburetor for a general-purpose engine handles a small flow rate, slight deviations in the fuel flow rate due to component dimensional variations, quality differences, assembly errors, etc. cannot be ignored. For this purpose, it is common practice to provide the carburetor with a manual adjustment valve that adjusts the fuel flow rate by changing the effective area of the fuel passage.

  The regulating valve is a screw rod screwed into the carburetor body, a needle-shaped valve element that is provided at the tip of the screw rod and inserted into the fuel passage to change its effective area steplessly, and at the base end of the screw rod A tool engaging head that protrudes outside the carburetor body and is operated by the carburetor / engine manufacturer or portable work machine manufacturer to adjust the fuel flow to the optimum level. It is supposed to ship. In addition, means for restricting re-adjustment at the time of shipment is applied to recover engine temporary malfunction that maintains engine performance against changes in the place of use and conditions. To further improve engine performance, users of portable work machines, etc. operate the regulating valve more than necessary, and as a result, the air-fuel mixture becomes too rich or too thin and falls outside the exhaust regulation compliance range, or the engine malfunctions or operates. I try not to make it impossible.

  As a means for restricting readjustment of the adjustment valve, a cap with an arm piece protruding outward is attached to the head of the adjustment valve, and a stopper that hits the arm piece against the carburetor body is provided so that readjustment within one rotation is possible. (See Patent Documents 1, 2, and 3). Further, as another readjustment limiting means, an adjustment valve provided in each of the main fuel passage and the low-speed fuel passage is arranged close to each other in parallel, and a cap having an arm piece protruding outward is provided on one adjustment valve. A stopper that is attached to the head and has the other adjusting valve as a stopper against which the arm piece hits, and that restricts the rotation of the adjusting valve with the cap attached (see Patent Documents 4 and 5), or the arm piece to the outside There is a type in which the protruding caps are mounted on the heads of the two regulating valves, and each of them serves as a stopper against which the other arm piece comes into contact to restrict the rotation of the regulating valves to each other (see Patent Documents 6 and 7). ).

  Each of the conventional caps has an arm piece that contacts the stopper protruding outward, and is attached to the head of the regulating valve with at least the portion of the cap projecting the arm piece exposed to the outside of the carburetor body. Is done. Most of the caps are made of synthetic resin, and are usually mounted so as to be integrally rotatable by biting into knurls formed on the outer peripheral surface of the head. For this reason, it is impossible for a user such as a portable work machine to prevent the arm piece from being cut out for the purpose of readjustment exceeding the limit, or forcibly removing or destroying the cap.

  In addition, the conventional cap is usually temporarily attached to the adjustment valve or the vaporizer body at the time of manufacture of the vaporizer so that it is not lost or forgotten to be attached. There is a case where it is required that the phase relationship with the stopper is not changed. That is, as described in Patent Documents 1, 2, 4, and 6, it is possible to readjust the mixture within the restricted range to both enrichment and dilution of the mixture. Those that can be readjusted only in the direction of dilution of the mixture, such as those described in 3, 5, and 7, will not cause readjustment in the direction that increases CO and HC in the exhaust. For this purpose, it is assumed that the cap is permanently attached at a phase where the arm piece hits the stopper.

However, since the cap described in Patent Documents 3 and 5 is temporarily attached to the adjusting valve in a freely rotating state, the arm piece does not necessarily hit the stopper and can be readjusted only in the direction of diluting the mixture. Is not to be done. On the other hand, since the cap described in Patent Document 7 is temporarily attached to the retainer provided in the vaporizer main body so that it cannot be pulled out and cannot be rotated, it can be readjusted only in the direction of diluting the air-fuel mixture by pushing it directly after adjustment. Can be installed. However, even in the device described in Patent Document 7, the problem that the deliberate destruction cannot be prevented since the portion where the arm piece of the cap protrudes is exposed to the outside of the retainer. In addition, since the temporary mounting is performed by the engagement and fitting of the retaining protrusion and the rotation-preventing protrusion formed on the cap with the stepped portion and the groove formed on the retainer, the structure is extremely complicated, especially the retainer. It is extremely difficult to apply when is made of the same metal as the vaporizer body.
US Pat. No. 3,618,906 Japanese Examined Patent Publication No. 47-42424 JP 2001-65408 A Japanese Utility Model Publication No. 61-134555 JP-A-6-317222 US Pat. No. 5,236,634 JP-A-8-82245

  The problem to be solved by the present invention is to attach a cap provided with an arm piece to a manual adjustment valve that continuously changes the effective area of the fuel passage, and the arm piece hits the stopper to prevent the adjustment valve from rotating beyond a certain level. The fuel adjustment device for a carburetor with readjustment limiting means to be mounted without worrying about the cap being intentionally removed or destroyed, and the phase relationship between this and the arm piece and the stopper For example, there has been no proposal that has been proposed so far that it is mounted in a fixed state so that it can be readjusted only in the air-fuel mixture diluting direction.

  In order to prevent the user such as a portable work machine from intentionally removing or destroying the cap attached to the head of the regulating valve, the present invention provides an insertion hole for fitting the cap into the carburetor body. And a stopper provided on the deep peripheral surface of the fitting hole and a locking member protruding on the shallow peripheral surface, and the cap provided with a recessed portion on the outer peripheral surface. The arm piece protrudes forward in the area within the outer diameter, and this cap is temporarily mounted to the carburetor body in a state where the cap member is fitted into the fitting hole and the locking member is fitted into the recess. Then, it was inserted into the head so as to be completely immersed in the insertion hole.

  In this way, when the cap is permanently attached to the head, it is completely immersed in the fitting hole, so that there is no part that will be exposed to the outside of the vaporizer body and removed or destroyed. Thus, the object of providing a readjustment limiting means which is impossible to readjust beyond the limit range is achieved.

  In addition to the above, the present invention is added to the above in order to eliminate both the fear of intentionally removing or destroying the cap and mounting the arm piece and the stopper in a constant phase relationship. It is assumed that when the cap is pushed in from the temporary mounting position, the arm piece is mounted on the head in such a phase that the arm piece is substantially adjacent to the stopper and can rotate only in the air-fuel mixture diluting direction.

  By doing in this way, the purpose of performing only readjustment within the exhaust regulation conforming range without increasing the CO and HC in the exhaust is achieved.

  As described above, according to the present invention, it becomes impossible for a user such as a portable work machine to remove or destroy the cap and perform readjustment exceeding the limit range, and in addition to this, mixing that does not deteriorate the exhaust state It is possible to readjust only the direction in which the air is diluted, so that the fuel flow rate can be adjusted by the user without causing the engine operating state to malfunction or become inoperable.

  The embodiment of the present invention will be described below with reference to the drawings. An adjustment valve 11 for adjusting the effective area of the fuel passage 2 formed in the carburetor body 1 is inserted into the fuel passage 2. From a needle-like valve body 12, a screw rod 13 screwed into the screw hole 3 of the vaporizer body 1, a shaft portion 14 protruding outward from the screw hole 3, a tool groove 15a and a knurling head 15b. Thus, the valve body 12 is the same as the conventional one that changes the effective area of the fuel passage 2 steplessly.

  On the surface of the carburetor main body 1 from which the adjustment valve 11 protrudes, a cylindrical wall 4 that is the same as the center of the adjustment valve 11 and that is integral with or separate from the carburetor main body 1, in this embodiment, projects. The internal space forms a fitting hole 5. Two protrusions are provided on the deep peripheral surface of the fitting hole 5 at a required phase, one of which functions as a stopper 6 and the other of which functions as an auxiliary stopper 7. Further, a side hole 8 is formed in a portion close to the tip of the cylindrical wall 4, and a locking member 28 made of a spherical body is fitted and held so as to be able to be pushed into the fitting hole 5 from the outside.

  Next, the cap 21 is fitted into the cap body 22 having an outer diameter that is fitted almost tightly into the fitting hole 5, and the mounting hole 23 that allows the knurled 15 b to be bitten by closely fitting the head 15 of the regulating valve 11. A tool insertion hole 24 and a tool groove 25 are provided, and an appropriately long groove-like recess 26 extending forward from the base end surface is provided on the outer peripheral surface of the cap main body 22, and the front end surface of the cap main body 22 is externally provided outside thereof. It is assumed that the arm piece 27 protrudes in an area within the diameter by integral formation.

  In the present embodiment having such a configuration, the screw rod 13 of the regulating valve 11 is first screwed into the screw hole 3 so that the effective area of the fuel passage 2 is set to a standard value by the valve body 12, and then the indentation portion 26 is formed. The cap 21 is fitted into the fitting hole 5 in the same phase as the locking member 28, and when the base end surface enters a little from the entrance of the fitting hole 5, the locking member 28 is pushed from the outer side of the cylindrical wall 4. 26 to be engaged. At this time, as shown in FIG. 3, the mounting hole 23 is not fitted into the head 15, the arm piece 27 has not reached the position where it hits the stopper 6, and the cap 21 is vaporized by the recess 26 and the locking member 28. The main body 1 is temporarily attached.

  In this temporarily mounted state, the cap 21 cannot be rotated because the engaging member 28 is fitted and engaged with the indented portion 26, and since it is not exposed from the fitting hole 5, it is substantially impossible to remove the cap 21. It is.

  When the carburetor temporarily mounted with the cap 21 is mounted on the engine, the effective area of the fuel passage 2 is adjusted so as to meet exhaust regulations by inserting a tool through the tool insertion hole 24 and turning the adjustment valve 11. When the adjustment is completed, the cap 21 is pushed in as it is, and the mounting hole 23 is completely mounted on the head 15 as shown in FIG. At this time, the recessed portion 26 is disengaged from the locking member 28 and positioned in front of it, and the arm piece 27 reaches a position where it substantially contacts the side surface of the stopper 6 over a wide area, and the cap 21 is permanently attached to the regulating valve 11. It will be. At this time, the cap 21 is completely immersed in a state where there is no gap in the outer periphery deep in the fitting hole 5, and it is impossible to remove or destroy the cap 21.

  In this embodiment, when the adjustment valve 11 is turned with the tip of the tool fitted in the tool groove 25 of the cap 21, the stopper 6 is installed so as to prevent the movement of the arm piece 27 in the air-fuel mixture concentration direction. Therefore, it is possible to readjust only the direction of dilution of the air-fuel mixture without increasing the CO or HC in the exhaust gas. In addition, since the auxiliary stopper 7 is provided with a certain central angle with the stopper 6 in the present embodiment, the arm piece 27 can move within this phase, so that the adjusting valve 11 is less than one revolution. For example, the rotation can be limited to about one-half rotation, and the fuel flow rate can be adjusted within a very small range so that the engine performance can be maintained and recovered within the exhaust regulation compliance range.

  Further, in the present embodiment, by appropriately setting the phase relationship between the stopper 6 and the locking member 28 and the recess 26 and the arm piece 27, the cap 21 can be simply pushed in from the temporarily mounted state. This can be mounted in a state where readjustment is possible only in the direction in which the mixture is diluted. Furthermore, in the present embodiment, it is possible to provide both the retaining and anti-rotation functions with a very simple temporary mounting means in which the engaging member 28 is fitted and engaged with the indented portion 26 whose front end is closed.

  The fitting hole 5 can be formed by providing a depression in the vaporizer body 1, and the depression 26 has a groove shape extending over the entire length of the cap 21, and the locking member 28 is fitted in the fitting hole 5. It can be the same as the key groove and key that always protrude. However, according to the present embodiment in which the fitting hole 5 is formed in the inner space of the cylindrical wall 4 and the indented portion 26 and the locking member 28 are as illustrated, there is a concern that the cap 21 may be pulled out or rotated. There is an advantage that the temporarily mounted state can be maintained without accompanying.

(A) by the side of the vaporizer body concerning an embodiment of the invention is a longitudinal section, and (B) is a sectional view which meets an AA line of (A). (A) of the cap which concerns on embodiment of this invention is a longitudinal cross-sectional view, (B) is a left view of (A). The longitudinal cross-sectional view which shows the state which mounted | wore with the cap temporarily. (A) which shows the state which mounted | wore with this cap is a longitudinal cross-sectional view, (B) is sectional drawing which follows the AA line of (A).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vaporizer body, 2 Fuel passage, 4 Cylindrical wall, 5 Insertion hole, 6 Stopper, 7 Auxiliary stopper, 11 Adjustment valve, 15 Head, 21 Cap, 26 Recessed part, 27 Arm piece, 28 Locking member

Claims (5)

A re-cover comprising a cap mounted on the head of a manual adjustment valve that continuously changes the effective area of the fuel passage, and a stopper that prevents the adjustment valve from rotating more than a certain amount by hitting an arm piece provided on the cap. In a fuel adjustment device for a carburetor having an adjustment limiting means,
A fitting hole for fitting the cap into the carburetor body is provided with the head protruding inside, and the stopper is provided on the deep peripheral surface of the fitting hole and protrudes on the shallow peripheral surface. It has a stop member,
The cap has a recess on the outer peripheral surface, and the arm piece projects forward in a region within the outer diameter,
Then, the cap is temporarily mounted in the carburetor body in a state where the cap is fitted into the fitting hole and the locking member is fitted and engaged with the indented portion, and is then pushed into the fitting hole. Worn on the head in a fully immersed state,
A fuel adjusting device characterized by that. A fuel conditioner for a carburetor according to claim 1,
When the cap is pushed in as it is from the temporary wearing position, the arm piece is attached to the head in a phase that is substantially adjacent to the stopper and is rotatable only in the air-fuel mixture diluting direction.
A fuel adjusting device characterized by that.   In addition to the stopper, an auxiliary stopper is provided on the deep peripheral surface of the fitting hole, the stopper prevents the adjustment valve from rotating in the direction of increasing the air-fuel mixture concentration, and the auxiliary stopper dilutes the air-fuel mixture. The fuel adjustment device for a carburetor according to claim 1 or 2, wherein rotation of the adjustment valve in a direction is limited.   The fuel adjustment device for a carburetor according to claim 1 or 2, wherein the cap is temporarily attached to the carburetor main body at a position where the cap is not exposed from the fitting hole. The fitting hole is formed by an internal space of a cylindrical wall projecting from the vaporizer body, the recessed portion extends forward from a base end surface of the cap, and has a groove shape with a closed front end. The cap is held on the cylindrical wall so as to be able to be pushed into the fitting hole from the outside, and the cap cannot be removed from the vaporizer body by pushing the engaging member into the recessed portion. 4. The fuel adjustment device for a carburetor according to claim 1, which is temporarily mounted so as not to rotate.

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