JP3868821B2 - Engine control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine control device that regulates the maximum engine speed, and more particularly to a control device that can be shared by a plurality of types of engines.
[0002]
[Prior art]
Conventionally, many general-purpose engines used as power sources for mowers, power sprayers, generators, etc. have a mechanical governor device as a throttle control mechanism to keep the engine speed constant regardless of load fluctuations. (Regulator) is used. This mechanical governor device is a mechanism that mechanically controls the opening degree of the throttle valve according to the engine speed, and uses the rotation of the crankshaft to swing the arm by centrifugal force, and the movement is performed by the link mechanism. This is transmitted to open and close the throttle valve.
[0003]
Such a governor device is generally composed of a governor shaft that rotates according to the engine speed, and a governor lever, a governor rod, and the like that transmit the movement of the governor shaft to a throttle valve. When the engine load becomes low, the governor lever rotates to the low speed side, and the throttle valve is driven by that amount, so that the engine speed is reduced according to the load. On the other hand, when the engine load becomes high, the governor lever is rotated in the reverse direction, and the engine speed increases. In this way, the engine speed is adjusted to be constant without being affected by load fluctuations.
[0004]
On the other hand, the governor lever is connected to the speed control lever via a governor spring, and the governor lever operates against the biasing force of the governor spring. The speed control lever is rotatably provided from the low speed operation position to the high speed operation position, and the control force of the governor spring increases as the speed control lever rotates from the low speed operation position toward the high speed operation position. Therefore, the tension of the governor spring increases toward the high-speed operation position, and the operation of the governor lever is restricted. Thus, for example, when the speed control lever is moved to the high speed operation position, the throttle valve is controlled in a relatively high opening range, and the engine continues to rotate at high speed.
[0005]
The speed control lever also has a function of regulating the maximum engine speed. That is, by preventing the rotation of the speed control lever at a certain position, the tension of the governor spring is restricted, and the operation of the governor lever at a predetermined rotational speed or more is secured to suppress an increase in the engine rotational speed. Japanese Utility Model Publication Nos. 6-22126 and 5-44578 disclose a mechanical governor device having such a function of restricting the maximum rotational speed, and the speed control lever is brought into contact with a stopper to rotate it. The movement is blocked and the engine speed is regulated.
[0006]
For example, in the former publication, bolts and lock nuts are used as stoppers for the speed control lever. In this case, a stopper bolt is attached to a substrate on which a speed control lever is pivotally supported, and a part of the lever is brought into contact with the stopper bolt to restrict its rotation. In this case, the contact position between the stopper bolt and the lever is set by the screwing position of the bolt, and after the bolt is arranged at a desired position, the bolt position is fixed by a lock nut.
[0007]
In the latter publication, bolts and compression coil springs are used as stoppers. As described above, here, part of the speed control lever is brought into contact with the stopper bolt to restrict its rotation, and the contact position between the stopper bolt and the lever is set by the screwing position of the bolt. In this case, a spring is extrapolated to the stopper bolt and is disposed between the head of the bolt and the substrate. The stopper bolt is prevented from loosening by the urging force of the spring and is fixed to the substrate.
[0008]
[Problems to be solved by the invention]
However, the speed control lever is generally provided at the upper part of the engine, and a fuel tank or the like is arranged there. For this reason, in the case of the former structure, there is a problem that adjustment work is difficult because a stopper bolt is arranged in a place where a tool such as a spanner for fixing the nut is difficult to enter, and a dedicated tool is required. .
[0009]
On the other hand, in the latter structure, the stopper position can be adjusted by simply removing the fixing nut and rotating the bolt, but a plurality of springs are prepared in advance to support several types of engines. It is necessary to keep. In other words, in the case of the same model, the latter configuration can easily cope with it, but if the displacement is different, the adjustment position may be greatly shifted, and there is a possibility that the optimal loosening load cannot be obtained with the same spring. . For this reason, it is necessary to prepare different springs for each model, and the latter configuration cannot cope with a plurality of models, resulting in an increase in the number of parts.
[0010]
An object of the present invention is to provide an engine control device that has good workability and can easily cope with a plurality of models.
[0011]
[Means for Solving the Problems]
An engine control device according to the present invention is connected to a throttle valve of an engine and is operated in a direction to close the throttle valve in response to an increase in the engine speed, and urges the governor lever in a direction to open the throttle valve. An engine control device having a governor spring that is pivotally supported on the substrate and a speed control lever that changes an urging force of the governor spring as the shaft is pivoted. A stopper bolt that abuts on the control lever and restricts the rotation of the speed control lever, a nut member that is screwed to the stopper bolt and is provided so as to be movable in the axial direction on the stopper bolt, Mounted between the nut member and the substrate, And having a stopper spring for applying a pressing force in the axial direction in Tsu bets member.
[0012]
In the present invention, the nut member is screwed onto the stopper bolt that restricts the rotation of the speed control lever, and the stopper spring is disposed between the nut member and the board to which the stopper bolt is attached. Adjustment of the contact position between the bolt and the speed control lever can be performed simply by rotating the stopper bolt. For this reason, it is possible to easily adjust the maximum engine speed without turning the nut member at a position where it is difficult to work or preparing a dedicated tool therefor. Also, compatibility with engines of different models can be performed only by adjusting the setting position of the nut member without changing the stopper spring, and there are few types of parts and a highly versatile engine that can handle multiple types of engines. A control device can be provided.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing an external appearance of a general-purpose engine to which an engine control apparatus according to an embodiment of the present invention is applied. The engine 1 is an air-cooled single-cylinder OHC type gasoline engine, and a crankcase 3 provided with a crankshaft 2 that is rotationally driven by a reciprocating motion of a piston is provided below the engine 1. A cylinder 4 is disposed above the crankcase 3, and a rocker cover 5 is attached to the cylinder 4. A carburetor 7 is attached to the intake side of the engine 1 together with the insulator 6. Outside air is introduced into the carburetor 7 through an air cleaner (not shown), where an air-fuel mixture with gasoline is produced and supplied to the engine 1.
[0014]
The carburetor 7 is provided with a throttle valve 8. The throttle valve 8 is opened and closed by a throttle lever 9 provided on the top of the carburetor 7. One end of a governor rod 10 is attached to the throttle lever 9, and the engine 1 is kept constant by an engine control device having a mechanical throttle control mechanism (governor) without being affected by load fluctuations. It has come to be adjusted.
[0015]
A governor shaft 11 is rotatably mounted on the crankcase 3, and a base end portion of a governor lever 12 is attached thereto. A governor spring 14 comprising a tension coil spring connected to a speed control lever 13 is hooked on the governor lever 12, and the governor lever 12 causes the governor lever 12 to open the throttle valve 8 in FIG. Is being energized. Further, one end side of the governor rod 10 is attached to the distal end side of the governor lever 12.
[0016]
The speed control lever 13 is rotatably supported by a holder (substrate) 15 attached to the upper part of the cylinder 4. The speed control lever 13 is provided with a low speed operation position L and a high speed operation position H, and the tension of the governor spring 14 increases as the speed control lever 13 rotates in the arrow X direction from the low speed operation position L toward the high speed operation position H. It is supposed to be. Accordingly, the urging force applied to the governor lever 12 increases toward the high-speed operation position H, and the operation (arrow B side) of the governor lever 12 in the direction to close the throttle valve 8 is restricted. As a result, the throttle valve 8 is controlled in a relatively high opening range, and the engine continues to rotate at high speed.
[0017]
On the other hand, the governor shaft 11 is engaged with a governor sleeve (not shown) that is slidably mounted in the axial direction on a shaft that is rotationally driven by the crankshaft 2 of the engine 1. A rotating body is fixed to the shaft, and a plurality of governor arms are rotatably mounted on the end surface of the shaft at a predetermined radius from the center of rotation. Each governor arm is integrally provided with a governor weight, which constitutes a mechanical governor mechanism. When the governor lever 12 rotates about the governor shaft 11 by this governor mechanism, the throttle lever 9 is actuated via the governor rod 10.
[0018]
For example, when the load of the engine 1 becomes low, the engine speed, that is, the rotational speed of the crankshaft 2 tends to temporarily increase by the amount of the load decrease. However, as the rotational speed increases, the centrifugal force applied to the governor weight increases, the governor arm opens, and the governor sleeve moves accordingly, and the governor shaft 11 rotates to the low speed side. The governor lever 12 is also rotated in the direction indicated by the arrow B together with the governor shaft 11, and the movement is transmitted to the throttle lever 9 via the governor rod 10, and the throttle valve 8 is driven in the closing direction. As a result, the engine speed is reduced in accordance with the load. On the other hand, when the engine load becomes high, the governor lever 12 is rotated in the reverse direction. Therefore, the engine speed is adjusted to be constant without being affected by load fluctuations.
[0019]
On the other hand, the speed control lever 13 also has a function of restricting the maximum engine speed. FIG. 2 is an explanatory diagram showing the configuration of the speed control lever 13 and the holder 15 used in the engine control apparatus. As shown in FIG. 2, the speed control lever 13 is rotatably attached to a lever shaft 21 provided in the holder 15. On the other hand, a stopper bolt 22 is attached to the holder 15, and the tip 22a of the stopper bolt 22 abuts against the stopper 23 of the speed control lever 13, so that the speed control lever 13 rotates in the direction indicated by the arrow X in the figure. Are now regulated. 2 shows a state in which the speed control lever 13 is at the high speed operation position H.
[0020]
The stopper bolt 22 is screwed into a screw hole 25 formed in a burring in the stopper mounting portion 24 of the holder 15, and is mounted so as to be movable in the axial direction by rotating the head 26 with a tool such as a screwdriver. . A nut (nut member) 28 is screwed to the threaded portion 27 of the stopper bolt 22 so as to be movable in the axial direction on the stopper bolt 22. Further, a stopper spring 29 is externally inserted into the stopper bolt 22 between the nut 28 and the stopper mounting portion 24. The stopper spring 29 applies a pressing force in the axial direction to the nut 28, thereby preventing the nut 28 from loosening.
[0021]
Therefore, a method for adjusting the maximum engine speed in the engine control device will be described in comparison with a conventional mechanism. 3 and 4 are explanatory views showing the structure of a conventional speed control lever. FIG. 3 shows the type of Japanese Utility Model Publication No. 6-22126, and FIG. 4 shows the type of Japanese Patent Application Laid-Open No. 5-44578. Members and parts similar to those of the engine control device of FIGS.
[0022]
In the speed control lever 13, first, a nut 28 is attached to the stopper bolt 22. In this case, the nut attachment position is predetermined according to the engine model, and the nut 28 is attached to each setting position indicated by color marking or the like. After the nut 28 is attached, the stopper spring 29 is extrapolated, and the stopper bolt 22 is screwed into the screw hole 25 with the nut 28 and the stopper spring 29 attached. Then, the contact position between the stopper bolt 22 and the speed control lever 13 is adjusted so that the maximum rotational speed of the engine 1 becomes a predetermined value. That is, the tip position of the stopper bolt 22 is adjusted by turning the head 26 to adjust the rotation limit of the speed control lever 13. At this time, the adjustment of the contact position can be performed only by rotating the head 26 of the stopper bolt 22. The nut 28 receives the pressing force of the stopper spring 29 and is fixed at the mounting position.
[0023]
On the other hand, when the stopper bolt 22 is applied to another model, the stopper spring 29 is not changed, but the set position of the nut 28 is adjusted to change the expansion / contraction amount of the stopper spring 29. That is, when the contact position between the stopper bolt 22 and the speed control lever 13 is shifted due to a difference in the exhaust amount or the like, the position of the nut 28 is changed so as to obtain an optimal loosening prevention load. This set position is determined in advance and can be easily changed by color marking or the like. Therefore, in the engine control device, it is not necessary to prepare the stopper spring 29 for each model, and the change is easy.
[0024]
On the other hand, in the conventional control mechanism, first, the stopper bolt 22 with the nut 28 attached is screwed into the screw hole 25 and the contact position with the speed control lever 13 is adjusted. Thereafter, the nut 28 is tightened and pressed against the stopper mounting portion 24 of the holder 15 to prevent loosening. However, in this case, as described above, the stopper bolt 22 is disposed in a place where a tool for fixing the nut 28 is difficult to enter, and thus such adjustment work is extremely difficult to perform.
[0025]
4, the stopper bolt 22 with the stopper spring 29 inserted is screwed into the screw hole 25, and the head 26 is turned to adjust the contact position with the speed control lever 13. Therefore, in this case, it is easier to adjust the stopper position than in the case of FIG. However, in this case as well, it is necessary to prepare different springs for each model as described above, and it is not possible to deal with a plurality of models.
[0026]
However, in this control device, adjustment of the contact position between the stopper bolt 22 and the speed control lever 13, that is, adjustment of the maximum engine speed can be performed only by rotating the head 26 of the stopper bolt 22. Further, it is possible to deal with engines of different models by adjusting the setting position of the nut 28 without changing the stopper spring 29. Therefore, according to the present invention, it is possible to easily adjust the maximum rotational speed of the engine, and to provide a highly versatile control mechanism with few types of parts.
[0027]
It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.
[0028]
For example, in order to more firmly prevent the nut 28 from being loosened, a bracket that abuts against the nut 28 from the stopper mounting portion 24 may be provided. In the above-described embodiment, a commercially available nut is used as the nut member. However, as long as it can be screwed to the stopper bolt 22 and can receive the stopper spring 29, for example, a screw is attached to a flat member. The thing which formed the hole may be used.
[0029]
【The invention's effect】
According to the engine control apparatus of the present invention, the nut member is screwed onto the stopper bolt that restricts the rotation of the speed control lever, and the stopper spring is disposed between the nut member and the board to which the stopper bolt is attached. Therefore, the contact position adjustment between the stopper bolt and the speed control lever can be performed only by rotating the stopper bolt. For this reason, it is possible to easily adjust the maximum engine speed without turning the nut member at a position where it is difficult to work or preparing a dedicated tool therefor. Also, compatibility with engines of different models can be performed only by adjusting the setting position of the nut member without changing the stopper spring, and there are few types of parts and a highly versatile engine that can handle multiple types of engines. A control device can be provided.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an external appearance of a general-purpose engine to which an engine control apparatus according to an embodiment of the present invention is applied.
FIG. 2 is an explanatory view showing a configuration of a speed control lever and a holder used in the engine control device of the present invention.
FIG. 3 is an explanatory view showing an example of a conventional speed control lever.
FIG. 4 is an explanatory view showing another example of a conventional speed control lever.
[Explanation of symbols]
1 Engine 8 Throttle valve 12 Governor lever 13 Speed control lever 14 Governor spring 15 Holder (board)
22 Stopper bolt 24 Stopper mounting part 28 Nut (nut member)
29 Stopper spring

Claims (1)

A governor lever connected to an engine throttle valve and operated to close the throttle valve in response to an increase in the engine speed, a governor spring biasing the governor lever in a direction to open the throttle valve, and a circuit board An engine control device having a speed control lever that is pivotally supported and changes a biasing force of the governor spring along with the rotation,
A stopper bolt that is attached to the substrate and contacts the speed control lever to restrict the rotation of the speed control lever;
A nut member screwed to the stopper bolt and provided on the stopper bolt so as to be movable in the axial direction;
An engine control device comprising: a stopper spring that is mounted between the nut member of the stopper bolt and the substrate and applies an axial pressing force to the nut member.

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