JPS6256358B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a blade angle control device for a fluid machine equipped with movable blades.

Conventionally, in fluid machines equipped with rotary blades, efficiency has been improved by making the blades movable and changing the pitch of the blades to adapt to the flow rate.

FIG. 1 is an example of a vertical sectional view of a movable vane pump. The shaft coupling 13 is fixed to one end of the rotating shaft,
The rotating shaft 1 enters the suction casing b via a blade angle control device a fixed to the suction casing b in a sealed manner, and a spindle-shaped movable blade main body c is fixed to the rotating shaft 1. A radial axis e is pivotally connected to the rotation axis 1 of the blade d at c, and the other end of a link h, which is pivotally attached to the end of arm f fixed to axis e by a pin g, is inserted through the rotation axis 1. It is pivotally connected to a crosshead j fixed to the blade angle control shaft 2 by a pin i. A device for moving the blade angle control shaft 2 in the axial direction is housed in the blade angle control device a.

When the blade angle control shaft 2 moves in the axial direction, the crosshead j moves together, and the link h rotates the arm f to change the pitch of the blade d. The figure shows an example of a horizontal type, but there is also a vertical type, and the same example exists for water turbines.

Such a blade angle control device is equipped with a blade angle control shaft for driving the movable blade in a rotary blade to which a movable blade of a fluid machine is attached, so that the blade angle control shaft can be moved in the axial direction. There are those in which the rotary shaft is used to support the rotary shaft, and those in which the rotary shaft is supported by a stationary object outside the rotary shaft. If the blade angle control shaft is supported by a stationary object to operate the movable blades, this acting force will act between the rotating shaft and the stationary object, and therefore the thrust bearing that supports the rotating shaft will , the disadvantage is that this additional acting force requires a larger capacity thrust bearing. On the other hand, the rotary shaft that supports the blade angle control force by the blade angle control shaft has a means for operating the blade angle control shaft on the rotary shaft, so the blade angle is controlled by the thrust bearing that supports the rotary shaft. There is no reaction to the force applied to the shaft. The actuating means provided on the rotating shaft generally has a construction in which a hydraulic cylinder is constructed coaxially with the rotating shaft, and the piston of the hydraulic cylinder is connected to the blade angle control shaft. but,
In the case of such a hydraulic type, it is necessary to have a hydraulic source, a hydraulic servo mechanism for controlling the position of the blade angle control shaft, etc., and the device becomes large and complicated. It is desirable to prepare for the On the other hand, in a structure that carries a device that mechanically operates the blade angle control shaft at all times during rotation of the rotary shaft, friction loss occurs in the bearing portion.

JP-A-57-212398 which supports the thrust force applied to the blade angle control shaft on the rotating shaft and uses a pair of spur gears.
In the invention of No. 1, since one of the gears and the control motor revolve around the rotation axis, uneven weight is generated and rotational balance must be taken, and a slip ring is required to supply power to the control motor. It takes a lot of work and requires maintenance. Further, there are drawbacks such as the length of the device in the axial direction becoming longer.

The present invention eliminates the drawbacks of the conventional example and provides a blade angle control device for a fluid machine equipped with movable blades, in which blade angle control is carried on a rotating shaft that does not generate large frictional resistance for blade angle control during fluid machine operation. The purpose of this invention is to provide a means for operating a shaft for use.

The present invention relates to a blade angle control device for a fluid machine equipped with movable blades having a hollow rotating shaft 1 and a blade angle controlling shaft 2 penetrating through the rotating shaft, in which relative rotation is made around the rotating shaft 1 with respect to the rotating shaft. A bridge 18 is provided with a spur gear on its outer periphery, a gear 24 is supported on a stationary member that meshes with the spur gear 18c of the bridge, and enables the bridge to move in the axial direction, and a fixed gear 24 that meshes with the gear 18c of the bridge allows the gear 24 to be moved at variable speed. The provided driving means 31 and the piece 18
This is a blade angle control device for a fluid machine including a movable blade having a mechanical motion conversion means whose output side is connected to a blade angle control shaft for converting the rotational movement of the rotor into an axial movement on the rotation axis.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a longitudinal sectional view. A blade angle control shaft 2 is inserted through the center of a hollow rotating shaft 1 of a fluid machine having movable blades (not shown) so as to be movable in the axial direction. Although not shown, a direct operating member connected to the movable blade is engaged with this blade angle control shaft 2. A disk-shaped disk 4 is fitted into the blade angle control shaft 2 via a key 3, and a nut 5 screwed into the male thread at the end of the blade angle control shaft 2 prevents the disk 4 from rotating in the axial direction. It is fixed to the blade angle control shaft 2 so that it does not move even when the blade angle is controlled. A plurality of operating rods 6 are fitted into axial holes on the circumference of the disk 4, and a nut 7 is screwed into the operating rods 6 to fix the disk 4 and the operating rods 6. The operating rod 6 is fitted into the rotating shaft 1 via a key 8, and is attached to a nut 9 screwed into the rotating shaft 1.
It slides into a bush 12 which is press-fitted into a coupling 11 which is axially tightened and fixed to the rotating shaft 1. The operating rod 6 is screwed into a sliding ring 16.

A driving shaft (if the fluid machine is a pump) or a driven shaft 13 (if the fluid machine is a water wheel) is fitted into the coupling ring 11, and the two are connected by a coupling bolt nut 14. A sliding ring 16 is fitted into the coupling ring 11 via a key 15 so as to be movable in the axial direction, and a female thread 18a on the inner circumference of a cylindrical piece 18 is screwed into a thread 11a on the outer circumference of the coupling ring 11. The piece 18 is supported via a bearing 17 so as not to move axially but rotatably relative to the sliding ring 16.
That is, the bearing 17 is made of an angular contact bearing that has been assembled with a frame.The outer ring of the bearing 17 is held down by the step 18b of the bearing house of the piece 18 and the flange collar 21 attached to the piece 18 by bolts 19, and the step of the sliding ring 16 is held on the side of the inner ring. It is holding 16a.

A spur gear 18c is provided on the outer periphery of the piece 18,
A spur gear 24 fixed to a blade angle operating force transmission shaft 20 parallel to the rotary shaft 1 supported by the casing 22 via a bearing 23 so as not to move in the axial direction is engaged with the spur gear 18c. A shifter 28 is engaged with the collar 21, and the shifter 28 is connected to the casing 2.
The housing cover 25 is movably slid into an axial guide provided on a casing cover 25 fixed to the housing cover 25. shifter 2
8 is a pointer 2 that passes through the casing 22 in the axial direction.
6 is fixed, and the position of the pointer 26 is detected by a blade angle detector 27 of a position detector such as a potentiometer or a differential transformer fixed to the casing 22 outside the casing 22, thereby transmitting the blade angle. The structure is such that

The end of the blade angle control force transmission shaft 20 is connected to a variable speed prime mover 31 via a shaft coupling 29 . The prime mover 31 is fixed to the casing 22 via a stand 32. A shaft sealing member 33 for sealing the rotating shaft 1 is fitted into the lower part of the casing 22, and the casing cover 2
A shaft sealing member 34 fixed to the shaft sealing member 5 seals the shaft of the coupling 11.

Prime mover 31 is typically a variable speed electric motor, but may also be a hydraulic or pneumatic motor. Alternatively, the blade angle control force transmission shaft 20 may be driven by another mechanism. Rotational speed detectors 30 and 40, such as reflective sensors, are provided opposite to the surfaces of the rotating shaft 1 and the shaft coupling 29 on which black and white patterns are printed.

The number of teeth of spur gear 18c is Z ₁ , and the number of teeth of spur gear 24 is
Let it be Z ₂ . Let the rotational speed of the rotating shaft 1 be N ₀ and the rotational speed of the prime mover 31 be N.

Now, assuming that N=N ₀ ×Z ₁ /Z ₂ , the blade angle control force transmission shaft 20 is rotated by the prime mover 31, the spur gear 24 rotates at the rotation speed N, and the spur gear 18c is rotated by N ₀ =N × Since it rotates at Z ₂ /Z ₁ and the piece 18 rotates at the same rotation speed as the rotating shaft 1, the piece 18 is not moved in the axial direction by the screw pairs 11a and 18a. Now, if N〓N ₀ ×Z ₁ /Z ₂ , then the rotation speed N ₁₈ of the piece 18 becomes N ₁₈ =N × Z ₂ /Z ₁ 〓N ₀ . Therefore, since the rotating shaft 1 and the piece 18 rotate relative to each other, the piece 18 is moved in the axial direction by the screw pair 11a, 18a, and the sliding ring 16 is moved through the bearing 17.
is moved, and the blade angle control shaft 2 is moved in the axial direction via the connecting rod 6 and the disk 4 to change the blade angle.

FIG. 3 is a block diagram of blade angle control.

(1) The signal detected by the blade angle detector 27 is sent to the blade angle comparator 36, which compares the current blade angle with the set value (or control command value) set by the blade angle setter 35. A signal proportional to the difference is sent to the three-point indicator 37.

(2) In the three-point indicator 37, if the signals from the blade angle detector 27 and the blade angle setter 35 are the same, a command to "keep the blade angle unchanged" (±0 rpm) is issued. If the current blade angle is higher than the command value, a "stand" command is sent to the three-point setter 39, and if it is up, a "lay down" command is sent to the three-point setter 39.

(3) The rotation speed detector 30 detects the rotation speed N ₀ of the rotating shaft 1, multiplies it by Z ₁ /Z ₂ using the proportional device 38, and inputs the result to the three-point setting device 39.

(4) The three-point setter 39 is based on the signal from the three-point indicator 38, N=N ₀ ×Z ₁ /Z ₂ +A, N ₀ ×Z ₁ /Z ₂ -A, N ₀ ×
Either signal Z ₁ /Z ₂ ±0 is sent to the rotation speed comparator 41.

(5) The rotation speed comparator 41 uses the signal from the three-point setting device 39 and the rotation speed detector 40 of the blade angle operation force transmission shaft 20.
The motor 31 is driven under feedback control by comparing the signals from the motor.

(6) Thus, when the blade angle is not controlled, the piece 18 rotates at N ₀ ×Z ₁ /Z ₂ ×Z ₂ /Z ₁ =N ₀ , and since the piece 18 does not rotate relative to the rotation axis 1, the blade angle changes. do not. When the prime mover 31 rotates at N ₀ ×Z ₁ /Z ₂ ±A, it is decelerated by the spur gear 24 and the spur gear 18c, and the piece 18 rotates at N ₁₈ = (N ₀ ×Z ₁ /Z ₂ ±A) × Z ₂ / Z ₁ =N ₀ ±A
Rotate at Z ₂ /Z ₁ . Therefore, the piece 18 rotates relative to the rotating shaft 1 at AZ ₂ /Z ₁ , and since the piece 18 moves in the axial direction, the blade angle changes.

The axial movement of the piece 18 results in the movement of the collar 21, which moves the shifter 28, and the pointer 26 moves to transmit the current blade angle to the blade angle detector 27.

(7) The signal from the blade angle detector 27 is sent to the blade angle comparator 36.
The signal corresponding to the set blade angle from the blade angle setter 35 is compared with the signal corresponding to the set blade angle, and when the difference becomes 0, the prime mover 31 performs N ₀ ×Z ₁ according to items (1) to (5) mentioned above. /Z ₂ ±0, the number of rotations N ₁₈ of the piece 18 is the same as that of the rotating shaft 1, and the rotating shaft 1 and the piece 18 rotate together.

In the embodiment, the piece 18 is rotated relative to the rotating shaft 1 and a screw pair is used for axial movement, but a cam may also be used. When using a cam, it can be realized by either a cylindrical cam or an end cam. That is, in the threaded pair portion of the embodiment, a cam groove is provided on the outer cylinder or the inner cylinder, and a cam follower that fits into the cam groove is provided on the other side. When an end cam is used, the end cam may be placed on the end face of the piece 18 and a cam follower fixed to the rotating shaft 1 side, or the opposite cam pair may be used.

In the embodiment, a variable speed prime mover drives a blade angle control force transmission shaft via a shaft coupling, but in this case, a constant speed prime mover, such as an induction motor, is connected to an electromagnetic coupling device 2.
9' (FIG. 3) to drive the blade angle control force transmission shaft, and the speed of the blade angle control force transmission shaft may be changed by controlling the electromagnetic coupling device 29'.

The present invention provides a piece on a rotating shaft so as to rotate relative to the rotating shaft, converts the rotational movement of the piece into an axial movement, and includes a member that transmits the axial movement of the piece to a blade angle control shaft. Since the thrust force applied to the blade angle operating shaft for blade angle control is carried by the rotary shaft, the thrust force for blade angle control is not applied to the bearing that carries the thrust force of the movable blade. The bearings can be small, and there is no need to modify the main body of the fluid machine when changing from fixed blades to movable blades. Furthermore, when a screw pair is used as a means for converting the rotary motion of the piece into linear motion, it is easy to prevent the piece from rotating in the opposite direction due to the thrust of the blade angle control.

A gear on the outer periphery of the piece that maintains its engagement even when the piece moves in the axial direction is fixed to the blade angle control force transmission shaft, and this shaft is rotated by the variable speed prime mover. When a fluid machine such as a pump is driven by a variable speed motor, the movable blades can be controlled by following the speed change of the variable speed motor of the pump. It is easy to do so. The variable-speed prime mover that drives the blade angle control force transmission shaft allows the relative rotational speed of the piece to be freely selected with respect to the rotation axis, making it possible to freely change the blade angle control operation time and perform optimal control. .

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view for explaining blade angle control of a fluid machine equipped with movable blades, Fig. 2 is a longitudinal cross-sectional view of an embodiment of the present invention, and Fig. 3 is a control block diagram for Fig. 2. be. 1...Rotation axis, 2...Blade angle control axis, 3...Key, 4...Disk, 5...Nut, 6...Operation axis, 7...Nut, 8...Key, 9...Nut ,
11...Cup ring, 11a...Screw, 12...
... Bush, 13 ... Shaft coupling, 14 ... Bolt nut, 15 ... Key, 16 ... Sliding ring, 16
a... Stage, 17... Bearing, 18... Piece, 18a...
...Female thread, 18b...Step, 18c...Spur gear, 1
9...Bolt, 20...Blade angle control force transmission shaft, 21
... Collar with collar, 22 ... Casing, 23 ...
... Bearing, 24 ... Spur gear, 25 ... Casing cover, 26 ... Pointer, 27 ... Blade angle detector, 28
... Shifter, 29 ... Shaft coupling, 30 ... Rotation speed detector, 31 ... Prime mover, 32 ... Stand, 33, 34
... Shaft sealing member, 35 ... Blade angle setting device, 36 ... Blade angle comparator, 37 ... Three-point indicator, 38 ... Proportional device, 39 ... Three-point setting device, 40 ... Rotation speed detection 41... Rotation speed comparator, 29'... Electromagnetic coupling device, a... Blade angle control device, b... Suction casing, c... Movable blade body, d... Blade, e
...shaft, f...arm, g...pin, h...ring, i...pin, j...crosshead.

Claims (1)

[Scope of Claims] 1. In a blade angle control device for a fluid machine equipped with a movable blade having a hollow rotating shaft 1 and a blade angle controlling shaft 2 passing through the rotating shaft, a rotating shaft is provided around the rotating shaft 1. A piece 18 is provided to be rotatable relative to the piece and has a spur gear on its outer periphery, and a gear 24 is journaled on a stationary member that meshes with the spur gear 18c of the piece and enables the piece to move in the axial direction.
, a fixed drive means 31 for varying the speed of the gear 24 that meshes with the gear 18c of the bridge, and a machine whose output side is connected to a blade angle control shaft for converting the rotational motion of the bridge 18 into axial motion on the rotation shaft. A blade angle control device for a fluid machine including a movable blade having a motion converting means. 2. The mechanical motion converting means includes a member fixed to the rotating shaft having a female thread cut in the piece and concentric with the rotating shaft, a screw that engages with the female thread, and a member fixed to the rotating shaft supporting the piece. 2. A blade angle control device for a fluid machine equipped with movable blades according to claim 1, comprising a sliding ring slidably inserted into a member movable in the axial direction of a rotating shaft.