JPS6215741B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention adjusts the opening amount of the throttle valve by balancing the operating force of the negative pressure actuator and the tension of the governor spring to maintain the rotational speed of the engine regardless of load fluctuations. This invention relates to a pneumatic governor device that maintains a constant state.

The basic structure of the pneumatic governor device is to operate a negative pressure actuator using the intake negative pressure in the intake passage on the leeward side of the throttle valve, and to balance this negative pressure operating force with the tension of the governor spring.

Since the opening area of the throttle valve relative to the opening/closing angle changes in a cosine curve X as shown in FIG. 2B, the intake negative pressure becomes a sine curve, and the valve closing output of the negative pressure actuator 7 also changes. It becomes a sinusoidal curve Y shown in FIG. 2A.

However, as shown in FIG. 1, the governor spring is drawn out in a tangential direction from the midpoint of the swing angle of the throttle lever 5, and the opening tension of the governor spring 6 relative to the closing angle of the throttle valve is As shown in Figure 2A, it changes to a substantially straight line Za.

Therefore, during light load operation of the engine, in the region where the throttle valve is close to fully closed, the valve opening tension of the governor spring becomes stronger than the valve closing output of the negative pressure actuator 6, causing the throttle valve to open. There was a problem in that the rotational speed of the engine increased because the rotation speed was biased towards the opposite direction.

The present invention has been proposed to solve the above problem, and when the engine is operated at a light load, the throttle valve swings toward the fully closed side and the output increase rate of the negative pressure actuator decreases. A governor spring that linearly changes the negative pressure reduction rate in the negative pressure operating chamber with a negative pressure regulating valve installed in the communication path when swinging toward the valve opening side, and linearly changes the output of the negative pressure actuator. This is to match the tension of the

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially longitudinal front view showing the structure of the pneumatic governor.

This pneumatic governor consists of a carburetor 2 and an air cleaner 3 that are sequentially attached to an intake pipe 1 of an engine (not shown), a throttle lever 5 that operates a throttle valve 4 of the carburetor 2, a governor spring 6, and a negative pressure actuator 7. is provided.

The base end 6a of the governor spring 6 is connected to a manually operated speed setting lever 27, and is adapted to pull and bias the governor lever 5 toward the opening side 8 of the throttle valve 4.

The negative pressure actuator 7 uses the intake negative pressure in the intake passage 10 to cause the diaphragm 12 of the negative pressure actuation chamber 11 to close to the return spring 1.
3, the throttle lever 5 is operated to the valve closing side 9 so that the throttle valve 4 is closed via the operating arm 14 extending from the diaphragm 12.

The negative pressure operating chamber 11 of the negative pressure actuator 7 is communicated with the intake passage 10 on the downstream side of the throttle valve 4 through a communication passage 15, and a negative pressure adjustment chamber 16 provided in a valve chamber 16 formed in the middle of this communication passage 15 is connected to the intake passage 10 on the downstream side of the throttle valve 4. The negative pressure in the negative pressure working chamber 12 is adjusted by a valve 17.

This negative pressure regulating valve 17 has a link 18 and a cam 19 connected to a throttle lever 5 that operates the throttle valve 4.
The throttle lever 5 is operated via an interlocking mechanism 20 consisting of a valve opening side 8.
When the valve body 21 of the negative pressure regulating valve 17 is pushed in against the return spring 22 through the interlocking mechanism 20, the passage cross-sectional area S of the valve chamber 16 is reduced, and the amount of air flowing through the communication passage 15 is reduced. This restricts the formation of negative pressure in the negative pressure working chamber 11.

The operation of the pneumatic governor configured as described above will be described below.

First, when the speed setting lever 27 is set to a desired engine speed position, the throttle valve 4 is opened via the throttle lever 5 in balance between the tension of the governor spring 6 and the operating force of the operating arm 14 of the negative pressure actuator 7. The system attempts to maintain the engine's rotational speed at a desired speed regardless of the weight or weight of the load.

When the rotation speed rises above the set value, the amount of air passing through the intake passage 10 increases, and the negative pressure in the intake passage 10 increases, and the diaphragm 12 of the negative pressure actuator 7 is moved to the return spring 13 via the communication passage 15. suction against the
The operating arm 14 operates the throttle lever 5 to the valve closing side 9.

On the other hand, during no-load operation of the engine, the throttle valve 4 swings toward the fully closed side, and when the load changes from no-load to light, the throttle valve 4 gradually opens.

At this time, the negative pressure in the intake pipe 10 changes in a curved manner, and the tension of the governor spring 6 changes in a substantially straight line Z as shown in FIG. 2A, while the output of the negative pressure actuator 7 However, the negative pressure regulating valve 17 provided in the communication passage 15 gradually narrows down the communication passage 15, and the output of the negative pressure actuator 7 changes to the linear shape Z of the governor spring 6. Match the tension.

This prevents the engine rotational speed from increasing in the light engine load range.

Moreover, what is shown in FIG. 3 and FIG. 4 shows different embodiments, and what is shown in FIG.
The negative pressure working chamber 11 is connected to the clean air chamber (intake passage 10 upstream of the throttle valve 4) 23 of the air cleaner 3 and the intake passage 10 downstream of the throttle valve 4 through communicating passages 15, respectively. A negative pressure regulating valve 17 that is interlocked with the throttle valve 4 via an interlocking mechanism 20 is provided in a communication passage 15 that communicates with the throttle valve 23 .

In this case, when the throttle valve 4 swings toward the valve-closing side 9 and the degree of increase in negative pressure in the intake passage 10 decreases, the passage cross-sectional area S of the communication passage 15 provided with the negative pressure regulating valve 17 is reduced to facilitate cleaning. From the air chamber 23 to the negative pressure working chamber 1
This is to reduce the amount of air flowing into the negative pressure working chamber 11 and increase the degree of increase in negative pressure in the negative pressure working chamber 11.

The device shown in FIG. 4 communicates the negative pressure working chamber 11 with the clean air chamber 23 and the intake passage 10 on the downstream side of the throttle valve 4 through communicating passages 15, 15, respectively. A negative pressure regulating valve 17 is provided which is linked to each throttle valve 4, and when the throttle valve 4 swings to the fully closed side 9 and the degree of increase in negative pressure in the intake passage 10 that drives the negative pressure actuator 7 decreases. , close the negative pressure regulating valve 17 provided in the communication passage 15 communicating with the clean air chamber 23 of the air cleaner 3 to restrict the inflow of air from the clean air chamber 23 to the negative pressure working chamber 11;
A negative pressure regulating valve 17 provided in the intake passage 10 on the downstream side of the throttle valve 4 is opened wide to cause a large amount of air in the negative pressure working chamber 11 to be sucked into the intake passage 10.

This increases the negative pressure increase rate in the negative pressure working chamber 11 and prevents the governor performance from going out of order during low load operation of the engine.

As explained above, the present invention is capable of adjusting the rate of decrease in negative pressure in a negative pressure operating chamber during light load operation, in which the throttle valve is gradually opened from the fully closed side, by using a negative pressure regulating valve provided in a communication passage. Since the output of the negative pressure actuator is made to match the linearly changing tension of the governor spring, the operating force of the negative pressure actuator is lower than the governor spring during light load operation of the engine as described in the conventional example. It is possible to reliably prevent the problem that the tension of the engine becomes strong and the throttle valve is biased toward the opening side, causing the engine rotational speed to increase.

Moreover, in the present invention, the negative pressure regulating valve provided in the communication passage is linked to the throttle valve, so that the communication passage opens as the throttle lever swings toward the valve opening side, and the negative pressure control valve provided in the communication passage opens as the throttle lever swings toward the valve opening side. The structure can be implemented simply by changing the negative pressure of the pressure actuator and can be implemented at low cost.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention, FIG. 1 is a partially vertical schematic front view showing the structure of a pneumatic governor attached to a carburetor engine, and FIG. 2A is a diagram showing the opening angle of the throttle valve. Indicates passage cross-sectional area change,
Fig. 2B is a graph showing the tension (output) of the governor spring and the output of the negative pressure actuator with respect to the throttle valve opening angle, and Figs. 3 and 4 are diagrams corresponding to Fig. 1 showing different embodiments. be. 2... Carburetor, 4... Throttle valve, 5... Throttle lever, 6... Governor spring, 7...
...Negative pressure actuator, 8... Valve opening side, 9... Valve closing side, 1
0... Negative pressure intake path, 11... Negative pressure working chamber, 15...
...Communication passage, 16...Valve chamber, 17...Negative pressure control valve,
20... Interlocking mechanism, 21... Valve body, S... Passage cross-sectional area.

Claims (1)

[Claims] 1. A throttle lever 4 of a carburetor 2 of an engine.
The governor spring 6 and the negative pressure actuator 7 are interlocked and connected, and the negative pressure actuation chamber 11 of the negative pressure actuator 7 is connected to the negative pressure intake path 10 on the downstream side of the throttle valve 4 through a communication passage 15.
The throttle valve 4 is configured to be driven to the valve opening side 8 by the governor spring 6 and to the valve closing side 9 by the negative pressure actuator 7 through the throttle lever 5, and the negative pressure operating chamber 11 is The valve chamber 16 of the negative pressure regulating valve 17 that adjusts the negative pressure of is communicated with the negative pressure working chamber 11,
The valve body 21 of the negative pressure regulating valve 17 is adjusted to the throttle valve 4 so as to satisfy the condition that the pressure reduction ratio of the negative pressure working chamber 11 to the negative pressure intake passage 10 decreases as the opening angle of the throttle valve 4 increases. A pneumatic governor device for a carburetor engine, characterized in that it is interlocked and connected to the engine via an interlocking mechanism 20. 2. The negative pressure regulating valve 17 is provided in the communication passage 15 that communicates the negative pressure working chamber 11 with the intake passage 10 downstream of the throttle valve 4, and the valve body of the negative pressure regulating valve 17 becomes smaller as the throttle valve 4 approaches fully open. 21 is a pneumatic governor device for a carburetor engine according to claim 1, in which the passage cross-sectional area of the valve chamber 16 is reduced through the interlocking mechanism 20. 3 The negative pressure working chamber 11 is communicated with the intake passage 10 on the upstream side of the throttle valve 4 through a communication passage 15, and this communication passage 1
5 is provided with a negative pressure regulating valve 17, and the passage cross-sectional area S of the valve chamber 16 of the negative pressure regulating valve 17 is increased by an interlocking mechanism 20 as the throttle valve 4 approaches full opening. The pneumatic governor device for the carburetor engine described in item 2.