JPH0623522B2 - Turbin turning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention is provided in a rotating machine such as a steam turbine and is used for correcting the bending of the rotor before starting or during cooling after stopping. The present invention relates to a turning device that rotates a rotor of a turbine at a low speed in order to prevent deformation of the rotor.

(Prior Art) Generally, in a rotating machine such as a turbine that uses high temperature steam or gas as a working fluid, it is necessary to minimize the bending of the turbine rotor in order to suppress vibration during normal operation. . Therefore, at the time of start-up after being stopped for a long period of time, the turbine rotor is rotated at a few revolutions per minute to correct the bending while stopped. In addition, since the turbine rotor may be permanently deformed due to residual heat immediately after the stop, the turning device is a device that rotates the turbine rotor at a few revolutions per minute during the cooling period as well as at the time of start. is there.

That is, FIG. 6 and FIG. 7 are diagrams showing a schematic configuration of a turning device used in a steam turbine, in which a gear 2 provided on an output shaft of a motor 1 is a reduction gear group 3
Of the reduction gear group 3, the rotational force of the gear 2 is sequentially reduced through the gears 4, 5, 6, 7, 8 of the reduction gear group 3 to form a gear 10 fixed to the turbine rotor shaft 9. It is designed to be transmitted.

By the way, since the turning operation is performed only when the turbine is stopped, the meshing between the gear 8 and the gear 10 is released during the operation of the turbine.

That is, FIG. 8 is an explanatory view of the operating mechanism of the turning device, in which each gear from the gear 4 to the gear 8 constituting the reduction gear group 3 is pivotally attached to the carrier 11, which carrier 11 It is possible to swing up and down about the same axis O as the axis of 5. The carrier 11 is suspended by a meshing lever 12 so as not to swing downward more than necessary, and the other end of the meshing lever 12 is connected to a piston rod 13a of an air cylinder 13. Further, a stopper 14 is provided on the upper surface of the carrier 11, and the stopper 14 contacts the base 15 to receive the reaction force of the rotational force of each gear, and the gears 8 and 10 are heightened so that the gears are properly meshed with each other. The height can be adjusted. On the other hand, a toggle mechanism 16 is connected to the meshing lever 12 so that the gears 8 and 10 can be accurately engaged and disengaged, and the carrier 11 is always spring-loaded at the top dead center and the bottom dead center. The structure is such that a force does not act to cause the carrier 11 to make an unstable movement. Reference numeral 17 in the figure is a weighted balance.

Then, in the turning device, the carrier 11 is at the bottom dead center position as shown in FIG.
The gear 8 and the gear 10 are not in mesh with each other.

Therefore, when the working air is supplied to the air cylinder 13, the reaction force of the toggle mechanism 16 is overcome and the carrier 11 is pulled up to bring the gear 8 and the gear 10 into contact with each other.

The meshing state of the gear 8 and the gear 10 differs depending on their relative positions, but at any relative position, the meshing is incomplete only when the gears 8 and 10 are in contact with each other. When the motor 1 is started in this state, the gear 9 does not rotate because the rotation resistance of the rotor 9 is large, only the gear 8 rotates, the carrier 11 rises, and the stop 14
When comes into contact with the base 15, the gear 8 and the gear 10 are completely meshed with each other, and the gear 10 starts rotating. In this state, the reaction force of the gear 10 is always transmitted via the gear 8 to the carrier 1
When the reaction force becomes greater than the weight of the carrier 11 and the spring force of the toggle mechanism 16, the carrier 11 receives the reaction force from the stopper 14 and holds the meshing position. After that, the force of the air cylinder 13 becomes unnecessary, so that the supply of the working air is stopped and the continuous turning operation is started.

When the turbine is started in the continuous turning operation state,
Torque is transmitted from the rotor 9 to the gear 10 and the reaction force of the gear 8 begins to decrease. By the way, since the motor 1 of the turning device generally uses an induction motor, when the reaction force of the gear 8 is reduced and the rotation speed of the motor 1 matches the synchronous rotation speed, the gear 8 and the gear 10 are meshed with each other. Will be incomplete. Then, when the gear 10 is further accelerated and becomes equal to or higher than the synchronous rotation speed of the motor 1, the gear 10 pushes the gear 8 downward, and the carrier 11 becomes the state shown in FIG.

(Problems to be Solved by the Invention) In the turning device, as described above, the motor 1
Since the induction motor is used for the motor, the motor is accelerated up to the turning speed immediately after the motor 1 is started. However, since the rotor 9 is stationary before the turning operation, a large-capacity motor 1 is required in order to overcome static friction and accelerate the rotor to a turning speed of several revolutions per minute.

On the other hand, since the resistance on the rotor 9 side during the turning operation causes dynamic friction, there is a difference of several times or more in the capacity required for the motor 1 when the motor 1 is started and during the turning operation.

Therefore, when a large capacity motor 1 is selected, the rotor 9 is accelerated immediately after the motor is started, and the rotation speed of the gear 10 is instantaneous, but exceeds the synchronous rotation speed of the motor 1, and the gears 8 and 10 mesh with each other. Is incomplete and the meshing is disengaged, which is a disadvantage. Moreover, since the resistance on the rotor 9 side changes with the operating state of the turbine and with the passage of time, the above-mentioned problems may be more serious.

Further, in a large turbine, a hydraulic device for jacking up the turbine rotor is provided to reduce the rotor resistance during turning, but in such a turbine, the resistance of the turbine rotor becomes extremely small.

FIG. 9 is a graph showing the relationship between the turning speed and the rotational resistance (torque) of the rotor, where the turning speed is 0.
The torque at the time, that is, the starting torque is indicated by a, the rotation resistance of the rotor becomes sharp when the turning is started, and the rotation resistance during the turning operation is indicated by b. According to the measurement results, both a and b change with the operating state of the turbine or with time, and b may be 1/10 to 1/100 of a.

However, in such a turbine, the rotor may spontaneously rotate beyond the turning speed due to disturbance, and it may be impossible to operate the turning by meshing gears. In such cases,
It suffices to set the turning speed higher than the natural speed of the rotor, but since the rotor having large rotor resistance and very large inertia is rotated at high speed, the motor becomes large. As the motor becomes larger, the output torque increases, and the acceleration force of the rotor also increases, making it more difficult to start, accelerate, and continuously operate the rotor.

In view of such a point, the present invention has an object to solve the problems of the above-mentioned conventional techniques and to obtain a turning device in which the meshing of gears is surely performed under any condition.

[Structure of Invention]

(Means for Solving Problems) The present invention relates to a motor, a gear group for decelerating the rotational speed of the motor and transmitting power to a gear integrally fixed to a shaft end of a turbine rotor, In a turning device of a turbine having an output side gear of this gear group and a device for engaging or disengaging the gear on the turbine rotor side,
The output shafts of two torque converters having different characteristics, that is, a large torque / low rotation speed torque converter and a small torque / large rotation speed torque converter, which are rotationally driven by the motor, are interlockingly connected via a one-way clutch,
The gear provided on the output side of the one-way clutch is meshed with the input side gear of the gear group.

(Operation) When starting each torque converter at the same time, when the resistance of the rotor is larger than the specified value, all of the torque converters work and the sum of the output shaft torque of each torque converter is output as the output torque. When the value becomes smaller than the predetermined value, only one torque converter acts on the output side by the action of the one-way clutch, and the output torque of the one torque converter is applied to the gear group. That is, by using at least two torque converters, it is possible to obtain a large starting torque and obtain an output shaft torque with a low torque during rotation, and the rotor shown in FIG. Can be

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

1 and 2, the gear 10 fixed to the shaft end of the turbine rotor 9 includes a gear 4 and a gear 4 as in the conventional case.
The gear 8 on the output side of the gear group consisting of 5, 6, 7, and 8 can be engaged or disengaged.

By the way, the base 15 has motors 20a, 20
A large torque / low rotation speed torque converter 21a and a small torque / large rotation speed torque converter 21b, which have different characteristics and are driven to rotate by b, are supported. A one-way clutch 22 is connected to the output shaft of the torque converter 21a, and a gear 2 that meshes with the input-side gear 4 of the gear group is fixed to the output-side end of the one-way clutch 22.

On the other hand, chain wheels 23 and 24 are provided on the output shaft of the torque converter 21b and the output side of the one-way clutch 22, respectively.
A chain 25 is wound between the four. The gears of the chain wheels 23 and 24 are determined so that the speed increasing ratio is 2 to 3 times. Further, the motors 20a and 20b are always rotated at a constant rotation speed N _1a ′ N _1b , respectively, and the rotor 9
The rotation speed N ₂ of the gear 2 changes in accordance with the resistance of No.

FIG. 3 is a diagram showing the relationship between the output shaft rotational speed N ₂ and the output shaft torque T of the torque converter in the above embodiment,
In this case, both torque converters have the same capacity, and the rotation of the torque converter 21b is doubled by the chain wheel 23 and the chain wheel 24 of the one-way clutch 22. Here, T ₁ is the output shaft torque when the torque converter and the gear group are directly connected,
T ₂ represents the output shaft torque when the speed is doubled between the torque converter and the gear group, and T ₁ and T ₂ are inversely proportional to the speed increasing ratio, and when the speed increasing ratio is doubled as described above. , T ₂ = 1 / 2T ₁ as the output shaft speed N ₂ doubles.

Therefore, when the two torque converters 21a and 21b are simultaneously moved, the output shaft torque T is 0 to 0 when the output shaft rotation speed N ₂ is 0.
In the range of 50%, the outputs from both torque converters are added, and T = T ₁ + T ₂ , the starting torque of 150% of the torque of T ₁ is generated, and when N ₂ is 50% or more, the torque from the torque converter 21b is increased. Only T ₂ is output.
That is, when N ₂ is 50% or more, the rotation speed on the output side of the one-way clutch 22 becomes higher than the rotation speed of the output shaft of the torque converter 21 a, so the output of the torque converter 21 a is transmitted to the output side of the one-way clutch 22. I will not be able to. Therefore, a large starting torque can be obtained at the time of starting when the rotor resistance is large, and the torque can be kept low while the rotor is rotating.

FIG. 4 is a diagram showing changes in the output shaft torque when the characteristics of the torque converter 21b are further optimized. When the turning device is started, a large starting torque is required due to the static friction of the rotor 9. Therefore, the rotor 9 remains stationary and the two torque converters 21a, 21a
When the output shaft torques T ₁ and T _{2 of} b are increased and the static friction is overcome, the rotor 9 starts to rotate and the friction of the rotor 9
The rotor 9 is accelerated along the curve of T while following the inertial force.

That is, since the torque converter 21a is connected to the gear 2 via the one-way clutch 22, when the rotation speed N ₂ of the output shaft of the one-way clutch 22 is smaller than the rotation speed N _2a of the output shaft of the torque converter 21a. ,
The one-way clutch 22 is activated, and the outputs from both torque converters 21a and 21b are applied to the output shaft of the one-way clutch 22.

Therefore, when N ₂ rises and reaches N _α which is larger than N _2a , the one-way clutch 22 is deactivated, and only the output from the torque converter 21b is transmitted to the output shaft of the one-way clutch 22. The rotor 9 is further accelerated along the curve of = T ₂ , and the rotor 9 is continuously operated at the point f where the resistance of the rotor 9 and the output shaft torque T _β are equalized.

Note that the reduction gear ratio of the gear group of the turning device is such that at the point e where the output shaft torque T of the torque converter becomes T = T ₂ = 0, the turning speed, that is, the speed of the gear 10 is 2rp.
It is set to be about m to 40 rpm.

On the other hand, if the resistance on the rotor 9 side changes due to disturbance or the like, the turning speed changes accordingly.

Generally, the turning speed of the turbine is sufficiently exerted at a rotation speed of about once every 30 minutes, but in the conventional one, it is set to about 1 to 5 rotations per minute due to the size of the reduction gear or the like. ing. However, since there is a track record of performing a turning operation for several tens of revolutions per minute, it can be said that the turbine body is not affected even if the turning revolution number is changed as in the present invention.

In the above embodiment, two motors and two torque converters are combined, but as shown in FIG. 5, the motor 20a is one and the torque motor 21a of the motor 20a is directly connected. The motor 20a and the torque converter 21b may be connected by the chain wheels 26, 27 and the chain 28. In this case, however, the device can be made compact by simply increasing the size of the motor.

〔The invention's effect〕

Since the present invention is configured as described above, when the rotor is low speed, the total output of the plurality of torque converters is transmitted to the rotor through the reduction gear group, and when the rotor is high speed, only the output from one torque converter is transmitted. By joining the rotor, it is possible to obtain torque characteristics that match the resistance of the rotor.
Further, when the rotation speed is high, the change in the output shaft torque T ₂ of the torque converter can be made small, so that the acceleration of the rotor can be suppressed to a low level, and smooth turning rotation can be obtained. Moreover, as described above, since the torque characteristic that matches the resistance of the rotor is generated, even if there is a sudden decrease in the rotor resistance or a disturbance that accelerates the rotor, a predetermined turning operation can be performed with the turning device connected. It can be continued.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a turbine turning device of the present invention, FIG. 2 is a mechanical diagram of the same as above, and FIG. 3 shows a change in output shaft torque with respect to an output shaft rotation speed when two torque converters are used. FIG. 4 is a characteristic explanatory diagram, FIG. 4 is a characteristic diagram of the torque converter of the present invention, FIG. 5 is a mechanism diagram of another embodiment of the present invention, and FIG. 6 is a diagram showing a configuration of a conventional turbine turning device. FIG. 7 is a mechanical diagram of the same as above, FIG. 8 is an explanatory diagram showing an operating device of a turbine turning device, and FIG. 9 is a resistance characteristic curve of a rotor. 2, 4, 5, 6, 7, 8, 10 ... Gear, 9 ... Rotor, 20a, 20b ... Motor, 21a, 21b ... Torque converter, 22 ... One-way clutch, 23,
24 …… Chien Wheel, 25 …… Chien.

Claims (1)

[Claims] 1. A motor, a gear group for decelerating the rotational speed of the motor and transmitting power to a gear integrally fixed to a shaft end of a turbine rotor, an output side gear of the gear group, and A turbine turning device having a device for engaging or disengaging a gear on the turbine rotor side, in a large torque / low speed torque converter and small torque / high speed torque converter rotationally driven by the motor. And two torque converters, the output shaft of a small torque / high rotation speed torque converter is interlockingly connected to the output side of a one-way clutch connected to a large torque / low rotation speed torque converter, and the one-way clutch A turbine turning device, characterized in that a gear provided on the output side of the clutch is meshed with an input side gear of the gear group.