JPH0218278B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of a blade wheel sealing device for a variable pitch type axial flow fluid machine.

[Prior art]

A blade wheel 1 of a variable pitch type axial flow fluid machine such as a variable pitch propeller or a side thruster is composed of a propeller blade 2, a propeller hub 3, and a built-in pitch changing mechanism 4, as shown in FIG. It is rotated via a propeller shaft 5 driven by a separately provided prime mover.

The pitch changing mechanism 4 of the blade wheel 1 includes a control fluid communication multiple pipe 6 supported slidably in the axial direction within the propeller shaft 5, a fluid pressure servo piston 7 within the propeller hub 3, and a hydraulic servo piston 7 within the propeller hub 3. It is composed of a joint bar 8, a crank 9, etc. for transmitting motion to the propeller blade 2 as a rotational motion. The supply/discharge path 6a of the control fluid communication multiple pipe 6
Alternatively, the control fluid is supplied to the servo chamber 10 or 11 of the servo piston 7 via the servo chamber 6b, and the control fluid in the other chamber 11 or 10 is discharged via the supply/discharge path 6b or 6a, and multiple pipes for control fluid communication are provided. The crank 9 operates within the servo chamber 11 by displacing the servo piston 7 together with the propeller shaft 5 and the propeller hub 3 in its axial direction.
It is now possible to change the pitch of the propeller blades 2 through, etc.

In addition to such a configuration, gravity oil is supplied within the propeller hub 3 to the sliding portion 12 between the propeller blade 2 and to compensate for the sealing pressure therebetween. This gravity oil is, for example, propeller shaft 5
The gravity oil is supplied to the pressure compensating gravity pressure chamber 13 formed independently of the servo chamber 11 through the gap 6A between the control fluid communication multiple pipe 6 and the gravity oil to the sliding portion 12. This is done via a gravity oil pipe 15 connected to the gap 14 shown in FIG. This gravity oil pipe 15 has a function of supplying gravity oil when the seal pressure decreases, and at the same time, recovering control fluid slightly leaking from the servo chamber 11 to the outside of the propeller hub 3.

Outside the gap 14 of the sliding portion 12, there are two oil seals 1 as shown in FIG.
A sealing member 18 consisting of 6 and 17 is interposed.
The former oil seal 16 mainly prevents the control fluid from leaking to the outside, and the latter oil seal 17 prevents the control fluid from leaking and also prevents dirt mixed in external seawater etc. from entering the propeller hub 3. It functions as a dust seal to prevent

[Problem that the invention seeks to solve]

Even if the function of the sealing member 18 described above is reduced, the pressure of the control fluid is higher than that of the outside, so
Seawater etc. should not enter the gap 14 of the sliding part 12, but in reality the propeller blade 2 is
By vibrating in the direction (see FIG. 1), the gap 2 between the seal members 18 in the sliding portion 12 is reduced.
The volume of 0 changes slightly periodically. This volume change phenomenon in the narrow gap 20 appears as a pumping effect that sucks seawater, etc., and the oil seal 1
The seawater sucked in between 6 and 17 flows into the oil seal 16.
This results in water being delivered to the gap 14 over the area.
Therefore, seawater mixes into the control fluid via the gravity oil pipe 15, the pressure compensation gravity pressure chamber 13, etc., and the control system of the impeller 1 of the variable pitch type axial flow fluid machine is mixed with the control fluid via the oil tank (not shown). It has the disadvantage of contaminating the whole area.

The present invention has been made to solve the above-mentioned problems, and aims to reduce as much as possible the pumping effect that occurs between the sealing member in the sliding part between the propeller blade and the propeller hub, and prevent contamination of the control system of the blade wheel. It is an object of the present invention to provide a blade wheel sealing device for a variable pitch type axial flow fluid machine that can be used in a variable pitch type axial flow type fluid machine.

[Means for solving problems]

The variable pitch blade wheel sealing device for a variable pitch axial flow fluid machine of the present invention has a variable pitch blade wheel sealing device for a variable pitch type axial flow fluid machine in which gravity pressure for pressure compensation is applied to the sliding part between a propeller hub and a propeller blade that slides on the propeller hub to change pitch. Applicable to pitch type axial flow fluid machines. The unique feature is that there are two
A seal member consisting of two oil seals is interposed, and a buffer chamber is formed in the sliding portion between the seal members, an accumulator is communicated with the buffer chamber, and a buffer pipe is connected to the buffer chamber. It is that you are.

〔Effect of the invention〕

In the present invention, a seal member consisting of two oil seals is interposed in the sliding portion of the propeller blade with the propeller hub, and a buffer chamber is formed in the sliding portion between the seal members, and the buffer chamber is provided with an accumulator. and a buffer pipe is connected to the buffer chamber, so even if the propeller blades vibrate, the pumping effect that occurs between the seal members in the sliding part is reduced as much as possible, and seawater suction is avoided. Contamination of the control system of the impeller can be prevented. Furthermore, the gravity pressure oil in the pressure compensation gravity pressure chamber can be adjusted to a desired pressure, and leakage of the control fluid from the sliding portion can also be avoided.

〔Example〕

The present invention will be explained in detail below based on examples thereof.

FIG. 4 is a sectional view of a propeller hub 3 including a blade wheel seal device 21 for a variable pitch type axial flow fluid machine according to the present invention. In the sliding part 12 between the propeller hub 3 and the propeller blade 2 that slides on the propeller hub 3 to change the pitch,
A gravity oil pipe 15 is provided for collecting control fluid leaking from the servo chamber 11 of the fluid pressure type servo piston 7 and applying gravity pressure for pressure compensation.

The sliding portion 1 is located radially outward of the impeller 1 from the gap 14 with which the open end 15a of the gravity oil pipe 15 communicates.
2 includes two oil seals 22 shown in FIG.
A sealing member 24 consisting of 23 is interposed, and the gap 20 of the sliding portion 12a between the sealing members 24 is
A buffer chamber 25 having a larger volume than this sliding gap is formed.

This buffer chamber 25 is the gap 20 of the sliding portion 12a.
This is to reduce the volume change rate of the sliding portion 12a including the buffer chamber 25 even if the propeller blade 2 vibrates and its volume changes by enlarging the space. Even with the volume of this buffer chamber 25, a desired small volume change rate may not be obtained. Therefore, an accumulator 26 as shown in FIG. It is designed to absorb fluctuations in the gravity hydraulic pressure in the chamber 25. The sliding portion 1 on the outer side in the radial direction of the impeller of the seal member 24 forming such a buffer chamber 25
Although not shown, if a dust seal similar to the oil seal 17 is interposed in the outer part 2b, the outer part 27
Therefore, it is possible to further prevent dirt in the seawater from entering the buffer chamber 25. Sliding portion 1 between this dust seal and the oil seal 23
Even if the above-mentioned pumping phenomenon occurs in 2b, the sucked seawater is sufficiently accommodated in the buffer chamber 25, so that water will not be sent beyond the oil seal 22 into the gap 14. Furthermore, as shown in FIGS. 4 and 5 described above, since a buffer pipe 28 is connected to the buffer chamber 25, gravity oil is separately supplied through this buffer pipe 28 independently of the gravity oil pipe 15. Alternatively, gravity oil contaminated with seawater that has entered the buffer chamber 25 can be recovered.

Since the present invention is configured as described above, it can be operated as follows. In FIG. 4, when the control fluid is supplied to the servo chamber 10 from the supply/discharge path 6a of the control fluid communication multiple pipe 6, the servo piston 7 is displaced rightward along the inner surface 29a of the servo cylinder 29. With this displacement, the propeller blade 2 rotates at the sliding portion 12 with the propeller hub 3 via the joint bar 8 and crank 9, and the propeller pitch is changed.

In response to the displacement of the servo piston 7, the control fluid in the servo chamber 11 is transferred to the control fluid communication multiple pipe 6.
It returns from the supply/discharge path 6b. Note that when providing a reverse pitch, the control fluid supply/discharge path is reversed. At this time, the control fluid leaking from the sliding portion 12 is separately returned to the oil tank from the gravity oil pipe 15 through the gap 6A between the control fluid conducting multiple pipe 6 and the propeller shaft 8. However, when the pressure compensation function of this gravity oil deteriorates, gravity pressure oil is supplied from the gravity oil pipe 15 to the gap 14, and the pressure balance in the sliding portion 12 is maintained.

By the way, even if the propeller blade 2 vibrates in the direction of arrow 19 described above and a volume change occurs in the sliding part 12, the volume change rate in the buffer chamber 25 provided in the sliding part 12a is small. , the pumping effect there is extremely small. Therefore, seawater or the like hardly ever enters the gravity oil pipe 15 through the sliding portion 12.

Moreover, since the accumulator 26 shown in FIG. 6 is interposed, the pumping effect can be further reduced, and the seawater is more
2 and contamination of the control system of the wheel 1 is avoided.

In addition, the buffer chamber 25 has a buffer tube 28 shown in FIG.
By keeping the gravity oil higher than the external pressure 27 and lower than the gap 14, the seawater suction remains in the buffer chamber 25 to prevent contamination of the control system within the gap 14. In addition, in this case, if there is a possibility that the gravity oil in the buffer chamber 25 leaks to the outside 27, the pressure thereof may be made equal to or lower than that of the outside 27.

In the above case, even if a pumping effect occurs even slightly in the buffer chamber 25 and seawater is mixed in, the contaminated gravity oil is separated from other uncontaminated gravity oil through the buffer pipe 28, and is removed from the gap 6B. It can also be recovered through the buffer tube 2
Although not shown in the figure, if 5 is made into a closed loop, the degree of contamination of the recovered gravity oil can be measured separately, which has the effect of facilitating maintenance and inspection.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of the impeller of a conventional variable pitch type axial flow fluid machine, Figure 2 is a sectional view of its propeller hub, Figure 3 is an enlarged view of section A in Figure 2, and Figure 4 is the main part. A basic sectional view of a propeller hub to which the variable pitch type axial fluid machine impeller seal device of the invention is applied;
FIG. 5 is a sectional view including a part of the configuration of the impeller sealing device of the present invention, and FIG. 6 is a sectional view showing the main part provided with an accumulator. 1...Wing wheel, 2...Propeller blade, 3...Propeller hub, 7...Servo piston, 12, 12a,
12b...Sliding part, 22, 23...Oil seal, 24...Seal member, 25...Buffer chamber, 26
...accumulator, 28...buffer tube.

Claims (1)

[Scope of Claims] 1. In a variable pitch axial flow fluid machine in which gravity pressure for pressure compensation is applied to the sliding part between a propeller hub and a propeller blade whose pitch is changed by sliding on the propeller hub, a propeller blade A sealing member consisting of two oil seals is interposed in the sliding portion with the propeller hub, and a buffer chamber is formed in the sliding portion between the sealing members, and an accumulator is communicated with the buffer chamber, and A blade wheel sealing device for a variable pitch axial flow fluid machine, characterized in that a buffer tube is connected to the buffer chamber.