JPH0144758Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a governor limit cylinder that adjusts the rotational speed of an engine.

As is well known, the governor limit cylinder, which is used in conjunction with a governor attached to a small engine in a small boat, transmits the force commanded by the operator to the governor to adjust the engine speed, and also controls the engine speed. When the lubricating oil pressure drops, the engine speed is automatically reduced to notify the operator that the lubricating oil level is low, thereby preventing engine burnout.

As shown in FIGS. 1 and 2, in this conventional governor restriction cylinder, a first piston 4 having a first piston rod 3 is slidably housed in a cylinder body 1. A second piston 10 is slidably housed in the formed piston chamber 7, and this second piston 10 has a second piston rod 12 on the side opposite to the first piston rod 3 side. In this conventional example, the first piston rod 3 is on the input side and the second piston rod 12 is on the output side. Then, while lubricating oil for the engine is supplied to the pressure side chamber 7b of the piston chamber 7 and the second piston 10 is moved forward in the right direction in the figure, the first piston rod 3 is pushed and pulled by an operating device not shown in the figure. The first piston 4 is moved in the axial direction within the range of stroke _S1 , and this movement amount is transferred to the second piston rod 1.
2 to a governor (not shown) to control the engine speed. Furthermore, when the lubricating oil pressure of the engine decreases, the governor reaction force becomes larger than the lubricating oil pressure, and the second piston 10 retreats to the left in the figure by a stroke _S2 , automatically lowering the engine speed. .

However, in the conventional governor restriction cylinder, both ends of the first piston 4 are brought into contact with the cylinder body 1 to set the stroke _S1 of the first piston 4, and the piston chamber is divided by the second piston 10. A supply chamber 5 communicating with the pressure side chamber 7b of the piston chamber 7 and an oil drain chamber 6 communicating with the atmosphere side chamber 7a of the piston chamber 7 divided by the second piston 10 are provided in series in the axial direction. 1 was long. As a result, the distance between the ends of the first piston rod 3 and the second piston rod 12 becomes large, which poses a difficult problem when installing the governor in a small engine, such as a small boat, where the installation space for the governor is small.

This idea was made in view of the above circumstances, and the strokes of the first and second pistons are the same as before, and the distance between the ends of the first piston rod and the second piston rod is reduced to shorten the overall length. The purpose of the invention is to form a first piston into a hollow piston having the length of the first piston rod, and to superpose a second piston and a second piston rod within the first piston. At the same time, the supply chamber and the oil drain chamber between the cylinder body and the first piston are formed parallel to the axial direction of the outer circumference of the first piston.

Examples of this invention are shown in Figures 3 to 6 below.
The explanation will be based on the description in the figures.

First, a first embodiment of this invention shown in FIGS. 3 and 4 will be described. A first piston 4, which is longer than the hollow cylinder body 1 and has a first piston rod 3 fixed to a piston lid 2 whose one end is sealed and fixed, is slidably housed in the cylinder body 1 with both ends open. ing. A supply chamber 5 and an oil drain chamber 6, which are elongated in the axial direction of the first piston 4, are formed on the inner circumferential surface of the cylinder body 1 that is in contact with the outer circumferential surface of the first piston 4. At least one each of the supply chamber 5 and the oil drain chamber 6 is required, and when a plurality of them are formed as in this embodiment, the supply chamber 5 and the oil drain chamber 6 are formed alternately. An inner fitting tube 9 having a rod support portion 8 formed thereon is inserted and fixed into the other end of the first piston 4, and a piston chamber 7 is formed within the first piston 4. A second piston 10 is slidably housed in the piston chamber 7, and a second piston rod 12 passing through the rod support 8 is connected to one end of the second piston 10. . In this example,
The first piston rod 3 is on the input side, and the second piston rod 12 is on the output side. The atmosphere side chamber 7a on the second piston rod 12 side of the piston chamber 7 divided into two by the second piston 10 is connected to the inner tube 9 and the first piston through a communication chamber 13 formed in the inner tube 9. The oil drain chamber 6 communicates with the drain port 15 through an oil drain hole 14 formed in the drain port 4 . The pressure side chamber 7b on the opposite side to the second piston rod 12 of the piston chamber 7 divided into two by the second piston 10 has an oil passage 16 formed between the outer periphery of the inner fitting tube 9 and the first piston 4, It communicates with the supply chamber 5 via a supply hole 17 formed in the first piston 4, and is supplied with engine lubricating oil introduced from a supply port 18 formed in the cylinder body 1. . At the end of the second piston 10 opposite to the second piston rod 12,
A safety rod 19 is connected to prevent the second piston 10 from coming out of the piston chamber 7 and to restrict the stroke of the second piston 10. still,
This safety rod 19 and the second piston rod 12 are made into one rod, and the second piston 10 is attached to this rod.
may be fixed externally. Said inner fitting tube 9
A locking pin 20 is fixed to the first piston 4 and has a tip thereof projected into the oil drain chamber 6 on the outer periphery of the first piston 4 . The tip of this locking pin 20 is connected to an axially long oil drain chamber 6 formed on the inner peripheral surface of the cylinder body 1.
Therefore, the movement of the first piston 4 in the axial direction, that is, the stroke, is from the stepped portions 6a to 6b of the oil drain chamber 6.
This is the distance S ₁ obtained by subtracting the length of the diameter of the locking pin 20 from the length up to this point. Incidentally, the tip of the locking pin 20 may be guided into the supply chamber 5 or a groove separately formed in the inner periphery of the cylinder body 1 instead of the oil drain chamber 6. The second piston 10, which is slidably housed in the piston chamber 7, is prevented from moving toward the second piston rod 12 by a stopper 21, which is a step formed at the end of the piston chamber 7 of the inner tube 9. The second piston rod 12
When moving to the opposite side, the tip of the safety rod 19 is the first
Since it is restricted by the piston 4 coming into contact with the piston lid 2, the axial movement or stroke of the second piston 10 is the movement distance _S2 of the tip of the safety rod 19.

Note that 23 and 24 are seal rings provided at both ends of the opening of the cylinder body 1, and these seal rings 23 and 24 are intended to prevent lubricating oil from leaking out of the cylinder body 1 from the low-pressure oil drain chamber 6. Therefore, the sliding resistance of the first piston 4 is reduced, and the operating force of the first piston rod 3 is small. Further, 26 is the piston cover 2 of the first piston 4.
This seal lid 26 is provided at the opening end on the opposite side, and the seal lid 26 prevents the lubricating oil leaking to the one end side of the rod support portion 8 from further leaking out of the first piston 4.

Next, the operation of the first embodiment of this invention having the above structure will be explained.

The governor limit cylinder shown in FIGS. 3 and 4 increases the rotational speed of the engine of a small boat in proportion to the distance by which the second piston rod 12 is moved in the opposite direction (to the right in the figure) from the first piston rod 3. This is a so-called push-type cylinder. In the state shown in FIG. 4, the first piston rod 3 is pushed and the locking pin 20 fixed to the first piston 4 is
is brought into contact with the stepped portion 6a of the second piston 12 side of the oil drain chamber 6, and lubricating oil of the engine is supplied to the piston chamber via the supply port 18, the supply chamber 5, the supply hole 7, and the oil passage 16. 7, the second piston 10 overcomes the reaction force of the governor and is in contact with the stopper 21. That is, in this state, the second piston rod 12 extends most in the direction opposite to the first piston rod 3, so the engine rotational speed is at its maximum.

If the lubricating oil pressure decreases due to oil leakage or other causes when the engine is operating at the highest rotational speed, this lubricating oil pressure will cause the second piston 1 to
Since the force pushing the second piston 10 toward the right in FIG. 4 due to the governor reaction force becomes weaker than the force pushing the second piston 10 toward the left in FIG. 4, the second piston 10 immediately moves toward the first piston rod 3. The tip of the safety rod 19 moves by a distance of stroke S ₂ where it comes into contact with the piston cover 2, and as a result, the governor, which was previously controlled to increase the engine speed, is now adjusted to reduce the engine speed. be done. The operator of a small boat or the like can immediately feel this decrease in rotational speed, so the locking pin 20 that fixed the first piston rod 3 to the first piston 4 locks the first piston rod in the oil drain chamber 6 in response to the rotational speed reduction command. 2nd by a distance of stroke S ₁ in contact with the stepped portion 6b on the 3rd side.
Move it in the opposite direction to the piston rod 12 (to the left in the figure). At this time, as mentioned above, the force pushing the second piston 10 to the right in FIG. 4 is weaker than the force pushing it to the left, so the second piston 10
The piston rod 3 moves together with the first piston 4, and the engine speed decreases further or stops. When the second piston 10 moves in the direction of the first piston rod 3, if the lubricating oil in the pressure side chamber 7b leaks from between the second piston 10 and the piston chamber 7 into the atmosphere side chamber 7a, the oil drain hole 14, Oil drain chamber 6
and is collected via the discharge port 15 into a tank (not shown).

If the cause of the decrease in lubricating oil pressure is discovered and this cause is eliminated, and this governor restriction cylinder is to be set again, lubricating oil is continuously supplied from a pump (not shown) to the pressure side chamber 7b of the piston chamber 7. supply,
Moreover, it is only necessary to push the first piston rod 3.
As a result, the state returns to the state shown in FIG. 4, and the rotational speed of the engine increases, and the small boat or the like moves forward.

Next, the second part of this invention shown in Figs. 5 and 6.
An example will be described.

The governor restriction cylinder of this embodiment is a so-called pull-type cylinder that increases the rotational speed of the engine of a small boat in proportion to the distance by which the second piston rod 12 is moved in the 3-direction of the first piston rod (to the left in the figure). It is. The difference from the first embodiment is that the second piston 10, which is slidably housed in the piston chamber 7 provided in the first piston 4,
The side of the second piston rod 12 that is divided into two is the pressure side chamber 7b into which lubricating oil for the engine is introduced, and the side opposite to the second piston rod 12 is the atmosphere side chamber 7a, and the second piston rod 12 is hollow and the atmosphere side chamber 7a. This is because the oil drain chamber 6 is communicated with each other. The stroke _S2 of the second piston 10 can be freely set by changing the position of the protuberance 27 formed on the second piston rod 12.

The operation of this second embodiment is the same as that of the first embodiment except that the push motion is changed to a pull motion, so a description thereof will be omitted.

In the first and second embodiments described above, the first piston rod 3 is used as the input side and the second piston rod 12 is used as the output side, but this is reversed and the second piston rod 12 is used as the input side and The first piston rod 3 may be used as the output side.

As is clear from the above description, the governor restriction cylinder of this invention has a first piston formed into a hollow piston having the length of the first piston rod, and a second piston and a second piston inside the first piston. The piston rods are arranged in an overlapping manner, and a supply chamber and an oil drain chamber are formed between the cylinder body and the first piston in parallel to the axial direction of the outer circumference of the first piston, so it is different from the conventional governor restriction cylinder. Compared to the case where both ends of the first piston are brought into contact with the cylinder body to set the stroke of the first piston, and the supply chamber and the oil drain chamber are formed in series in the axial direction of the first piston, as shown in FIG. Although the stroke of each of the first piston and the second piston is the same as before, it is possible to shorten the length of the cylinder body and make it compact, so that both ends of the first piston rod and the second piston rod are As a result, it becomes possible to easily install a small engine with a small space for installing a governor, such as in a small boat.

[Brief explanation of the drawing]

1 and 2 show a conventional governor restriction cylinder, FIG. 1 is a sectional view taken along the - line in FIG. 2, FIG. 2 is a sectional view taken along the - line in FIG. 1,
3 and 4 show the first embodiment of this invention, and FIG. 3 is a side view taken along the - line in FIG.
Figure 4 is a sectional view taken along the - line in Figure 3;
6 and 6 show another embodiment of this invention, FIG. 5 is a sectional view taken along the line - in FIG. 6, and FIG. 6 is a sectional view taken along the line - in FIG. 5, respectively. DESCRIPTION OF SYMBOLS 1... Cylinder body, 3... First piston rod, 4... First piston, 5... Supply chamber, 6...
Oil drain chamber, 7...Piston chamber, 7a...Atmospheric side chamber,
7b...Pressure side chamber, 10...Second piston, 12
...Second piston rod, 13...Discharge port,
18... Supply port.

Claims (1)

[Claims for Utility Model Registration] A cylinder body, a first piston that is slidably fitted in the outer cylinder body in the axial direction and has a first piston rod at one end, and a piston chamber formed in the first piston. a second piston that is slidably housed in the cylinder body and has a second piston rod on the side opposite to the first piston rod; and a second piston formed between the cylinder body and the first piston and separated by the second piston; a supply chamber communicating with a pressure side chamber and a supply port of the piston chamber; and an atmosphere side chamber of the piston chamber formed between the cylinder body and the first piston and separated by the second piston. and a drain chamber communicating with the drain port, the first piston being formed into a hollow piston having the length of the first piston rod, and the second piston being disposed within the first piston. 1. A governor-limiting cylinder characterized in that a piston and a second piston rod are arranged in a superimposed manner, and the supply chamber and the oil drain chamber are formed parallel to each other in the axial direction of the outer periphery of the cylinder body.