JPH01206131A - Cylinder - Google Patents

Abstract

PURPOSE:To improve a machine and reduce the size thereof by mounting an external control means which opens the relief valve of a piston and externally forming a gas chamber which gives pressure to the oil inside an oil chamber via a hollow part communicated with an oil chamber behind the cylinder. CONSTITUTION:When a relief valve 6 is opened with a control lever 13, an oil chamber A is communicated with both an oil chamber B and a hollow part 6A so that a piston rod 3 is capable of making sliding action in the proceeding or retiring direction according to the direction of the external force to said rod 3. At this time, the pressure in the air chamber 6B as a gas chamber acts on the working oil inside the oil chambers A and B via the hollow part 6A to reflect the proceeding action of the piston rod 3 according to the differential pressure receiving area of the piston 2. However, the air chamber 6B formed externally is capable of having sufficient capacity so that the stable proceeding force will act regardless of the stroke position. On the other hand when the relief valve 8 is closed with the control lever 13, the flowing of working oil into and out of the oil chamber A is cut off so that the present position of the piston rod 3 is maintained stable. However, if an excessive proceeding load is applied, the relief valve 8 is opened to permit the piston rod 3 to proceed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cylinder used as a positioning and supporting member for various types of equipment.

(Prior art) A tilt damper installed between a boat hull and an outboard motor for positioning and supporting a port outboard motor is, for example, a piston that is slidably housed in a cylinder body and has oil chambers on both sides. A cylinder is known in which a communicating orifice and a relief valve are provided, a piston rod connected to the piston projects axially from the cylinder body, and gas is sealed in the upper part of the oil chamber above the piston (Japanese Patent Publication No. 59-1989). No. 5480).

The orifice installed in the piston provides a suitable amount of resistance to the expansion and contraction of the piston rod, smoothing the rotation of the outboard motor, and the relief valve opens when a load exceeds a certain level, preventing the outboard motor from colliding with an obstacle. Alleviate the impact of time. In addition, the gas sealed in the upper part of the cylinder body compensates for oil volume fluctuations caused by piston sliding, pressurizes the hydraulic oil, and biases the piston in the direction of extension due to the difference in pressure receiving area, thereby lifting the outboard motor. It is designed to assist.

(Problem to be solved by the invention) However, in this tilt damper, the oil chambers on both sides of the piston are always in communication through the orifice, so even though the outboard motor can be set in the propulsion position and the floating position,
It cannot be stopped at an intermediate rotation position. For this reason, it is impossible to set the outboard motor at a desired angle depending on the water depth, etc. unless a supporting member is prepared separately, and if this cylinder is applied to something other than an outboard motor, This is difficult to apply to devices that need to be held in arbitrary positions.

Furthermore, this cylinder has a soot sealed in the upper part of the cylinder body, but in order to stably bias the piston rod in the direction of extension over the entire stroke, it is necessary to enclose a large amount of soot. For this reason, the overall length of the cylinder body becomes long, and there is a problem in that the intervening position is limited.

The present invention was made to solve the above problem α, and an object of the present invention is to provide a cylinder that can be positioned and held at any extended position and has a short overall length.

(Means for Achieving the Object) The present invention combines a hollow piston rod with a piston that is slidably housed inside a cylinder body, so that the piston rod protrudes from the cylinder body so that it can slide freely. Oil room A
The piston is provided with a relief valve that communicates with the hollow part of the piston rod, and is provided with operating means for opening this relief valve by external operation. A gas chamber is provided outside the cylinder body and is filled with a gas that directly communicates with the cylinder body and pressurizes the hydraulic oil in the oil chambers A and B through this hollow portion.

(Function) When the relief valve is opened by operating the operating means, oil chamber A becomes oil chamber B.
The piston rod communicates with the hollow part of the piston rod, so the piston rod moves in either direction of expansion or contraction depending on the applied external force. At this time, the pressure in the gas chamber acts on the hydraulic oil in oil chambers A and B through the hollow part of the piston rod, exerting a stretching force on the piston rod according to the difference in pressure receiving area of the piston. The gas chamber can have a sufficiently large capacity and exerts a stable extension force on the piston rod regardless of the stroke position.

On the other hand, when the relief valve is closed by repeatedly operating the operating means, the oil chamber A
Since the outflow and inflow of hydraulic oil to the piston rod is blocked, the piston rod is stably held in that position. However, even in this state, the relief valve opens to allow the piston rod to extend in response to the action of an excessive extension load.

(Example) FIG. 1 shows a first embodiment of the present invention.

In this figure, 1 is a cylinder body filled with hydraulic oil;
2 is a piston that is slidably housed in the cylinder body, 3
is a hollow piston rod connected to the piston 2 and protruding from the cylinder body 1 in a freely sliding manner.

The inside of the cylinder body 1 is defined by the piston 2 into an oil chamber A at the front and an oil chamber B at the rear. The hollow portion of the piston rod 3 is defined by a free piston 4 housed in a freely slidable manner into an oil reservoir chamber 5 filled with hydraulic oil and an air chamber 6A filled with compressed air as a gas chamber. Furthermore, a boat 1 is provided in an air chamber 6A outside the base end of the piston rod 3.
An air chamber 6B is provided which communicates through the air chamber 4.

The piston 3 is provided with a boat 7 that communicates the oil chamber B and the oil reservoir chamber 5, and a relief valve 8 that communicates the oil chamber A with the oil reservoir chamber 5. The relief valve 8 is provided at the center of the piston 3 so as to face the oil reservoir chamber 5 from the oil chamber A side, and is biased by a relief spring 8A interposed on the oil chamber A side. sit down.

On the other hand, an operating rod 10 is disposed vertically through the hollow portion of the piston rod 3 as an operating means for forcibly opening the relief valve 8. The operating rod 10 has one end in contact with the oil reservoir chamber 5iIII and the leaf valve 7, and after freely sliding through the free piston 4, the other end is connected to the outer side of the plug 11 defining the air chamber 6B at the base end of the piston rod 3. protrudes freely and slides into place. An operating lever 13, which is swingably attached to a bracket 12 integral with the plug 11, comes into contact with this protruding end. Note that 15 is an air valve for replenishing air into the air chambers 6A and 6B.

Next, the effect will be explained.

When you want to extend or contract the piston rod 3, operate the operating lever 13 and push the operating rod 10 into the piston rod 3, and the relief valve 8 will release the relief spring 8.
A opens against the oil chamber A, and the oil chamber A communicates with the oil reservoir chamber 5.

If an external force is applied in this state, the piston rod 3 and piston 2 will slide toward the extension side or the contraction side depending on the direction of the external force, and hydraulic oil will flow through the boat 7 and the relief valve 8. Fluctuations in the amount of oil in the oil chambers A and B due to this sliding movement are compensated for by the sliding movement of the 7-Lee piston 4 facing the oil reservoir chamber 5 of the accumulator.

Note that the air chamber 6B is provided outside the piston rod 3, and together with the air chamber 6A, sufficient air capacity is ensured. However, the pressures in the air chambers 6A and 6B do not change significantly, and a stable stretching force acts on the piston rod 3 regardless of its sliding position. Therefore, for example, when installed in an outboard motor, the outboard motor rotates smoothly by applying a certain external force. Note that by providing the air chamber 6B outside, the capacity of the air chamber 6A can be reduced, so there is no need to increase the overall length of the cylinder in order to secure the air capacity.

Now, when the piston rod 3 has moved to the desired position, when the operating lever 13 is returned, the relief valve 8 closes while pushing back the operating rod 10 by the repulsive force of the relief spring 8A. This blocks the flow of hydraulic oil into and out of the oil chamber Δ.
The piston rod 3 stops at that position. therefore,
By operating the operating lever 13, for example, the outboard motor can be stopped at any position during rotation.

In this state, the compression load applied to the piston rod 3 is supported by the hydraulic oil in the oil chamber A whose outflow is locked, so that the piston 2 is completely prevented from sliding toward the compression side. Furthermore, when an extension load is applied, the piston 2 tries to slide in the extension direction, but at this time hydraulic oil flows into the IJ-7
The oil chamber A blocked by the valve 8 becomes negative pressure, and a large pressure difference is generated on both sides of the piston 2. This pressure difference is the piston 2
It provides resistance to the sliding of the piston 2, and at the same time as the extension load is removed, the slid piston 2 returns to its original stop position. In this way, the piston 2 and piston rod 3 are stably held at the stop position within the range of normal load fluctuations.

On the other hand, for example, when an outboard motor collides with an underwater obstacle, an abnormal stretching force (impact) acts on the cylinder. In this case, the pressure difference on both sides of the piston 2 increases rapidly and exceeds the relief pressure of the spring 8A, causing the relief valve 8 to open.
While sliding in the extension direction while allowing hydraulic oil to flow into the oil chamber A, a depressing force based on the relief pressure of the relief valve 8 is generated to absorb and alleviate the shock applied to the outboard motor.

In this case, even after the impact load disappears, the piston 2 and the piston rod 3 do not return to their original positions and remain in their original positions.

FIG. 2 shows a second embodiment of the invention.

Here, an accumulator 20 consisting of a free piston 4, an oil reservoir chamber 5, and an air chamber 6 is provided outside the cylinder body 1 independently from the piston rod 3.
The oil chambers A and B communicate with the oil reservoir chamber 5 of the accumulator 20 via an oil passage 21 formed inside the piston rod 3. The other configurations are the same as in the first embodiment.

In this case, since no air chamber is provided inside the piston rod 3, the total length of the cylinder can be further shortened.

(Effects of the Invention) As described above, the present invention provides a relief valve between the oil chamber in which the piston enters inside the cylinder body and the hollow portion of the piston rod, and an operating means for opening the relief valve by external operation. Because of this, the piston rod can be extended or contracted to any desired position when the relief valve is opened via the operating means, and the piston rod can be held at that position by closing the relief valve.

In addition, since the gas chamber for pressurizing the hydraulic oil is configured externally,
Sufficient large capacity can be obtained. Therefore, the piston rod is stably biased in the direction of extension, and the dimensions of the piston rod and cylinder body can be set regardless of the large capacity, so the entire cylinder can be shortened and the cylinder installation position can be more freely adjusted. can be selected.

Therefore, according to the present invention, it is possible to improve the g performance and reduce the size of the positioning and supporting cylinder.

[Brief explanation of the drawing]

DESCRIPTION OF SYMBOLS 1... Cylinder body, 2... Piston, 3... Piston rod, 4... Free piston, 5... Oil reservoir chamber, 6°G A, 6 B... Air chamber, 8... ... Relief valve, 10... Operating rod, 13... Operating lever,
20...Accumulator, A, B...Oil chamber.

Claims (1)

[Claims] A relief that connects a hollow piston rod to a piston that is slidably housed inside the cylinder body so that it protrudes freely from the cylinder body, and communicates the oil chamber A in front of the piston with the hollow part of the piston rod. A valve is provided on the piston, and an operating means is provided to open the relief valve by external operation.The oil chamber B defined at the rear of the piston is in direct communication with the hollow part, and the oil is supplied through the hollow part. A cylinder characterized in that a gas chamber filled with gas for pressurizing hydraulic oil in chambers A and B is provided on the outside of the cylinder body.