Turning device

A turning device includes: a driving source; a main drive gear rotationally driven by the driving source; a driven gear that engages with the main drive gear and is rotated integrally with a rotated body, wherein the turning device rotationally drives the driving source to rotate the rotated body; a movement mechanism that causes the main drive gear to reciprocate in an axial direction between a separated position at which engagement of the main drive gear and the driven gear is released and an engaged position at which the main drive gear engages with the driven gear; a forward rotation mechanism that intermittently rotates the main drive gear; and a reverse rotation mechanism that intermittently rotates the main drive gear in a direction opposite to a direction by the forward rotation mechanism.

TECHNICAL FIELD

The present invention relates to a turning device that rotates a turbine rotor in a steam turbine, a gas turbine, or the like.

BACKGROUND ART

A turbine rotor is used as a rotated body in, for example, a steam turbine, a gas turbine, and a power generation plant applied to a combined cycle including a combination thereof. If the turbine rotor is left in a stopped state with high temperature after operation, the turbine rotor may be bent, in some cases, due to thermal distortion of the turbine rotor caused by temperature difference in a turbine casing along with temperature decrease of the steam or the gas inside a turbine, or due to own weight of the rotor.

Accordingly, to prevent the turbine rotor from being bent, it is necessary to perform turning in which the turbine rotor is rotated at a low speed for a predetermined time during the operation stop of the steam turbine, or the like. A turning device that rotates the turbine rotor by power of a motor is widely used to perform such turning.

The turning device has been subjected to various improvements for prevention of breakage and delay of deterioration with time. For example, Patent Literature 1 discloses a turning device including a reverse rotation preventing unit at a shaft end of a pinion shaft. The reverse rotation preventing unit prevents reverse rotation of the pinion shaft and a one-way clutch that transmits rotating force of the turning motor to the pinion shaft, in order to prevent the turning device from being reversely rotated and being damaged when the turbine rotor is reversely rotated.

CITATION LIST

Patent Literature

Incidentally, the turning device transmits the rotating force of the turning motor through a pinion gear provided on the pinion shaft and a wheel gear rotated integrally with the turbine rotor, and causes the pinion gear and the wheel gear to automatically engage with each other. In the present circumstances, however, if engagement operation is stopped halfway due to some factors, the turning device does not include a mechanism automatically performing restoration as with the turning device disclosed in Patent Literature 1, and it is necessary to perform manual restoration.

SUMMARY

One or more embodiments of the present invention provide a turning device that is restored easily even if the engagement operation of the pinion shaft is stopped halfway due to some factors.

A turning device according to one or more embodiments of the present invention is provided with a driving source, a main drive gear configured to be rotationally driven by the driving source, and a driven gear configured to engage with the main drive gear and to be rotated integrally with a rotated body, and the turning device rotationally drives the driving source to rotate the rotated body. The turning device includes: a movement mechanism configured to cause the main drive gear to reciprocate in an axial direction between a separated position at which engagement of the main drive gear and the driven gear is released and an engaged position at which the main drive gear engages with the driven gear; a forward rotation mechanism configured to intermittently rotate the main drive gear; and a reverse rotation mechanism configured to intermittently rotate the main drive gear in a direction opposite to a direction by the forward rotation mechanism.

In one or more embodiments of the present invention, the forward rotation mechanism includes a forward rotating body that is fixed to a rotary shaft of the main drive gear, and a forward rotation actuator that forward rotates the forward rotating body, and the reverse rotation mechanism includes a reverse rotating body that is fixed to the rotary shaft of the main drive gear, and a reverse rotation actuator that reversely rotates the reverse rotating body.

The turning device according to one or more embodiments of the present invention further includes a first detection sensor configured to detect a phase of the main drive gear in a rotation direction, and the main drive gear is rotated forward by the forward rotation mechanism or is rotated reversely by the reverse rotation mechanism, based on a result of detection by the first detection sensor.

In the turning device according to one or more embodiments of the present invention, it is determined that engagement operation of the main drive gear and the driven gear is stopped in a case where the first detection sensor does not detect variation of the phase for a predetermined time.

In the turning device according to one or more embodiments of the present invention, when it is determined that the engagement operation of the main drive gear and the driven gear is stopped, the movement mechanism moves the main drive gear to the separated position, and the reverse rotation mechanism reversely rotates the main drive gear.

The turning device according to one or more embodiments of the present invention further includes a second detection sensor configured to detect that the main drive gear reversely rotated is located at the separated position, and the forward rotation mechanism forward rotates again the main drive gear located at the separated position when the second detection sensor detects that the main drive gear is located at the separated position.

According to one or more embodiments of the present invention, even if the engagement operation of the pinion gear and the wheel gear is stopped halfway due to some factors, the reverse rotation mechanism reversely rotates the pinion shaft, which makes it possible to cause the pinion gear and the wheel gear to engage with each other. Accordingly, a restoration work is easily performed as compared with manual operation.

DETAILED DESCRIPTION

Embodiments of a turning device according to the present invention are described below with reference to accompanying drawings.

As illustrated inFIG. 1andFIG. 2, a turning device1according to one or more embodiments is used while being coupled to a turbine rotor90as a rotated body. For example, the turning device1rotates the turbine rotor90at a low speed of several rotation per minute for a predetermined time while operation of a steam turbine is stopped, to prevent the turbine rotor90from being slightly bent due to own weight of the turbine rotor90.

To rotate the turbine rotor90at a low speed for a predetermined time, as illustrated inFIG. 1, the turning device1includes: a turning motor11serving as a driving source that rotates an output shaft (not illustrated) at a predetermined rotation frequency by power supplied from a power supply; a reduction gear12that is connected to the output shaft of the turning motor11and reduces the rotation frequency at a constant speed ratio (reduction ratio) to transmit the rotation frequency to an output shaft12A; a power transmission unit13that includes, as a component, a turning motor-side sprocket17coupled to a shaft end of the output shaft12A; a pinion gear15serving as a main drive gear attached to a pinion shaft14that configures the power transmission unit13; and a wheel gear16serving as a driven gear that is configured to be engageable with the pinion gear15and is fixed to the turbine rotor90.

The turning device1includes a tachometer21that detects the rotation speed of the turbine rotor90. The rotation speed of the turbine rotor90detected by the tachometer21is continuously transmitted to a control section23provided in the turning device1, through a signal line not illustrated.

The control section23controls operation of the turning device1and includes a computer device.

The control section23acquires a detection result in the tachometer21, a first proximity switch61, a second proximity switch62, and a third proximity switch63. The control section23controls operation of the turning motor11, a forward rotation hydraulic cylinder51, a reverse rotation hydraulic cylinder53, and a fitting/releasing hydraulic cylinder57, based on the acquired detection results.

The power transmission unit13includes the turning motor-side sprocket17that is fixed to the reduction gear12as a driving side and a pinion gear-side sprocket unit18as a driven side. A chain19is wound around the turning motor-side sprocket17and the pinion gear-side sprocket unit18, and rotational driving force of the turning motor-side sprocket17is transmitted to the pinion gear-side sprocket unit18through the chain19. The pinion gear-side sprocket unit18is fixed to a shaft end of the pinion shaft14as a rotary shaft.

The pinion gear15has a cylindrical shape and has a thread provided in a spiral shape on an outer peripheral surface. The pinion gear15is fixed to the pinion shaft14while the pinion shaft14penetrates through a center of the pinion gear15. The pinion gear15is attached to the pinion shaft14so as to be rotated integrally with the pinion shaft14, and to be relatively reciprocatable in an axis direction C (lateral direction inFIG. 2) relative to the pinion shaft14as illustrated inFIG. 2.

The wheel gear16has an annular shape, and includes a tooth profile engageable with the pinion gear15on an outer peripheral surface, thereby serving as a gear. The wheel gear16is fixed to the turbine rotor90to transmit the rotational driving force outputted from the turning device1, to the turbine rotor90.

The turning device1causes the pinion gear15and the wheel gear16to engage with each other, or releases engagement of the pinion gear15and the wheel gear16to be separated from each other. To do that, the turning device1includes a forward rotation mechanism and a reverse rotation mechanism. More specifically, as illustrated inFIG. 2, the turning device1includes, as a component of the forward rotation mechanism, a forward rotating body31that intermittently rotates the pinion shaft14in a clockwise direction. In addition, the turning device1includes, as a component of the reverse rotation mechanism, a reverse rotating body33that intermittently rotates the pinion shaft14in a counterclockwise direction. Further, the turning device1includes a fitting/releasing lever35that is connected to one end of the pinion gear15, as a component of a movement mechanism that causes the main drive gear to reciprocate between a separated position and an engaged position in an axial direction C.

The forward rotating body31and the reverse rotating body33are members that are coaxially fixed to the pinion shaft14with a distance therebetween. Note that, in one or more embodiments, clockwise rotation corresponds to the forward rotation and counterclockwise rotation corresponds to the reverse rotation as an example.

As illustrated inFIG. 3, the forward rotating body31has a disc shape, and includes a plurality of protrusions31A that are provided with equal intervals on an outer peripheral surface. A side surface31B of each of the protrusions31A is formed so as to engage with a front end of a push rod51A that is a piston rod of the forward rotation hydraulic cylinder51described later. The forward rotating body31is fixed to the pinion shaft14while the pinion shaft14penetrates through an inner cavity of the forward rotating body31. This makes it possible to transmit rotation of the forward rotating body31to the pinion shaft14.

The forward rotation hydraulic cylinder51as a forward rotation actuator that rotates the forward rotating body31forward, is provided around the forward rotating body31. The forward rotation hydraulic cylinder51is swingably supported, by a pin76, to a front end of a first mount71that is fixed to an inner surface of a gearbox70. The forward rotation hydraulic cylinder51is disposed at a predetermined position by being pulled by a tension spring79so as to come into contact with a front end of a stopper78.

Further, paired pipes77A and77A are connected to the forward rotation hydraulic cylinder51. Working fluid is supplied to or discharged from the forward rotation hydraulic cylinder51through the pipes77A and77A from a switching valve77that is operated in response to an electric signal or other signal provided from the first proximity switch61as a first detection sensor. As a result, the push rod51A is advanced and retreated. When the push rod51A is advanced, the front end of the push rod51A engages with any of the plurality of protrusions31A provided on the outer peripheral surface of the forward rotating body31, and the forward rotating body31is accordingly rotated forward.

As illustrated inFIG. 4, the reverse rotating body33has a disc shape, and includes a plurality of protrusions33A that are provided with equal intervals on an outer peripheral surface. A side surface33D of each of the protrusions33A is provided in a state where each of the protrusions31A of the forward rotating body31is inverted laterally, and is formed so as to engage with a front end of a push rod53A of the reverse rotation hydraulic cylinder53described later. Further, the reverse rotating body33includes a plurality of convex parts33B and a plurality of concave parts33C with different thicknesses on a surface of the reverse rotating body33on a side facing the first proximity switch61described later, in order to specify a rotating position. The convex parts33B and the concave parts33C each have a fan-shaped flat surface, and are alternately arranged and coupled to form an annular shape. Specification of the rotating position makes it possible to detect a phase, in the rotating direction, of the pinion shaft14that is fixed to the reverse rotating body33and is rotated at the same time.

The reverse rotating body33is fixed to the pinion shaft14while the pinion shaft14penetrates through a center of the reverse rotating body33. In one or more embodiments, as illustrated inFIG. 2, the reverse rotating body33is fixed to the pinion shaft14with an interval from the forward rotating body31in the axial direction C of the pinion shaft14. The reverse rotating body33also transmits the rotation to the pinion shaft14, as with the forward rotating body31.

As illustrated inFIG. 4, the first proximity switch61is provided on side close to one of surfaces of the reverse rotating body33so as to face the convex parts33B and the concave parts33C. When the reverse rotating body33is rotated, the first proximity switch61distinguishes and detects a period in which the first proximity switch61faces any of the convex parts33B and a period in which the first proximity switch61faces any of the concave parts33C. The first proximity switch61is fixed to a third mount73fixed to an inner surface inside the gearbox70.

Further, the reverse rotation hydraulic cylinder53as a reverse rotation actuator that rotates the reverse rotating body33reversely, is provided on outside of the reverse rotating body33in a radial direction, in a manner similar to the forward rotation hydraulic cylinder51. In other words, the reverse rotation hydraulic cylinder53is swingably supported, by the pin76, to a front end of a second mount72that is fixed to the inner surface (not illustrated) of the gearbox70. The reverse rotation hydraulic cylinder53is disposed at a predetermined position by being pulled by the tension spring79so as to come into contact with the front end of the stopper78.

Further, the paired pipes77A and77A are connected to the reverse rotation hydraulic cylinder53. Working fluid is supplied to or discharged from the reverse rotation hydraulic cylinder53through the pipes77A and77A from the switching valve77that is operated in response to an electric signal or other signal provided from the first proximity switch61. As a result, the reverse rotation hydraulic cylinder53advances and retreats the push rod53A. When the push rod53A is advanced, the front end of the push rod53A engages with any of the plurality of protrusions33A provided on the outer peripheral surface of the reverse rotating body33, and the reverse rotating body33is accordingly rotated reversely.

Next, as illustrated inFIG. 2, the fitting/releasing lever35has an L-shape, and a vicinity of an upper end35B is rotatably supported by a rotary shaft35A and swings around the rotary shaft35A. Further, a lower end35C of the fitting/releasing lever35is locked between paired annular walls14A and14A that are fixed to the pinion shaft14. The lower end35C is locked so as to allow rotation of the pinion gear15but to retrain movement of the pinion gear15in the axial direction C in a state of being housed between the annular walls14A and14A. As a result, the pinion gear15is allowed in rotation in a circumferential direction and linearly moved from the separated position (virtual line on left side inFIG. 2) to the engaged position (solid line on right side inFIG. 2), or from the engaged position to the separated position, along with the swing of the fitting/releasing lever35.

As illustrated inFIG. 2, the second proximity switch62serving as a second detection sensor and the third proximity switch63serving as a third detection sensor are provided side by side in a horizontal direction with a predetermined interval therebetween, near the upper end35B of the fitting/releasing lever35. The second proximity switch62and the third proximity switch63are provided at positions that are separated by a predetermined distance from the upper end35B of the fitting/releasing lever35in a vertical direction. The second proximity switch62is relatively disposed on right side of the third proximity switch63. When the pinion gear15is moved in an engaging direction A along with the swing movement of the fitting/releasing lever35, the upper end35B moves in a separating direction B opposite to the engaging direction A. Accordingly, when the pinion gear15is located at the separated position, the upper end35B faces the second proximity switch62, and the second proximity switch62detects that the fitting/releasing lever35is located at the separated position. In addition, when the pinion gear15is located at the engaged position, the upper end35B faces the third proximity switch63, and the third proximity switch63detects that the fitting/releasing lever35is located at the engaged position. The second proximity switch62detects that the pinion gear15is located at the separated position, and the third proximity switch63detects that the pinion gear15is located at the separated position, in the above-described manner.

The fitting/releasing lever35is caused to swing by the fitting/releasing hydraulic cylinder57as a fitting/releasing actuator. Front end side of the piston rod57A is rotatably coupled to the fitting/releasing lever35, and the fitting/releasing hydraulic cylinder57advances and retreats the piston rod57A to cause the fitting/releasing lever35to swing.

The paired pipes77A and77A are connected to the fitting/releasing hydraulic cylinder57. Working fluid is supplied to or discharged from the fitting/releasing hydraulic cylinder57through the pipes77A and77A from the switching valve77that is operated in response to an electric signal or other signal provided from the second proximity switch62and the third proximity switch63. As a result, the piston rod57A is advanced or retreated. When the piston rod57A is advanced, the pinion gear15is moved to the engaged position. When the piston rod57A is retreated, the pinion gear15is moved to the separated position.

Next, operation of the turning device1is described with reference toFIG. 5andFIG. 6. In the description of the operation, a normal state where the engagement operation of the pinion gear15and the wheel gear16is smoothly completed is first described with reference toFIG. 5, and then, an abnormal state where the engagement operation of the pinion gear15and the wheel gear16is stopped halfway is described with reference toFIG. 6.

Note that, inFIG. 5andFIG. 6, as for the tachometer21, black painting indicates stop of the rotation of the turbine rotor90. Further, as for the first proximity switch61, the second proximity switch62, and the third proximity switch63, black painting indicates detection of a target member. Moreover, as for the forward rotation hydraulic cylinder51, the reverse rotation hydraulic cylinder53, and the fitting/releasing hydraulic cylinder57, black painting indicates that the working fluid is supplied in a direction in which the respective piston rods are advanced. Further, as for the turning motor11, black painting indicates that the turning motor11is rotationally driven. Furthermore, a display dimension indicates a time.

[Operation in Normal State]

When the tachometer21detects that the rotation of the turbine rotor90has been stopped (at speed of zero), and detects that the turbine has been completely stopped, forward rotation operation is performed after a time T1elapses from the detection as illustrated inFIG. 5. More specifically, operation in which the push rod51A is advanced from the forward rotation hydraulic cylinder51for a time T2, and then, the push rod51A is retreated to the forward rotation hydraulic cylinder51for the time T2is performed. The pinion shaft14and the pinion gear15are slightly rotated forward by one forward rotation operation. The pinion shaft14and the pinion gear15are gradually rotated forward through repetition of the forward rotation operation, and the first proximity switch61detects the phase. This causes the pinion gear15to be located at a specific position in the circumferential direction.

After a time T3elapses from the phase detection by the first proximity switch61, the piston rod57A is advanced from the fitting/releasing hydraulic cylinder57. The pinion gear15that is located at the separated position illustrated by a dashed line inFIG. 2is moved in the engaging direction A through swing of the fitting/releasing lever35along with the movement of the piston rod57A, and the pinion gear15is brought into contact with the wheel gear16.

The pinion gear15is continuously moved in the engaging direction A even after the pinion gear15and the wheel gear16are brought into contact with each other. In addition, after a time T4elapses from the phase detection, the forward rotation operation of the pinion gear15by the forward rotation hydraulic cylinder51is resumed. Accordingly, an engaging degree of the pinion gear15and the wheel gear16is gradually increased. In this process, when the fitting/releasing lever35reaches from the position detected by the second proximity switch62to the position detected by the third proximity switch63, the engagement of the pinion gear15and the wheel gear16is detected. Thereafter, the forward rotation operation by the forward rotation hydraulic cylinder51is continuously performed until a time T5elapses after the engagement is detected by the third proximity switch63, and the engagement operation of the pinion gear15and the wheel gear16is then completed. At this time, the time T5is set for completion of the engagement operation on the assumption that all of the tooth of the pinion gear15are respectively engaged with the tooth of the wheel gear16.

The movement of the pinion gear15in the direction A is stopped at a time when the pinion gear15and the wheel gear16completely engage with each other, and the pinion shaft14is rotated by the turning motor11to start turning after a time T13elapses from the engagement detection.

Next, operation in the abnormal state where the engagement of the pinion gear15and the wheel gear16is incomplete due to some factors, is described with reference toFIG. 6.

When the tachometer21detects that the rotation of the turbine rotor90has been stopped (at speed of zero) and detects that the turbine has been completely stopped, the pinion gear15and the wheel gear16are brought into contact with each other, and the forward rotation operation by the forward rotation hydraulic cylinder51is resumed at a time point I. These operation are similar to those in the normal state.

In a case where the first proximity switch61is not switched for a time T6after the forward rotation operation by the forward rotation hydraulic cylinder51is resumed, one of the convex part33B or the concave part33C is continuously detected, and it is determined that the engagement operation is stopped halfway due to some factors.

Therefore, the push rod51A of the forward rotation hydraulic cylinder51is retreated, and the reverse rotation operation is performed after a time T8elapses. More specifically, operation in which the push rod53A of the reverse rotation hydraulic cylinder53is advanced for a time T9, and then, the push rod53A of the reverse rotation hydraulic cylinder53is retreated for the time T9, is performed. The pinion shaft14and the pinion gear15are slightly rotated reversely by one reverse rotation operation. The pinion shaft14and the pinion gear15are gradually rotated reversely through repetition of the reverse rotation operation.

Further, retreat of the piston rod57A of the fitting/releasing hydraulic cylinder57is started before a time T7elapses after the push rod51A of the forward rotation hydraulic cylinder51is retreated. When the fitting/releasing lever35accordingly reaches the position detected by the second proximity switch62, the separation of the pinion gear15and the wheel gear16is detected.

Then, after a time T10elapses from the separation detection, the forward rotation operation is performed again, and the phase is detected by the first proximity switch61. After a time T11elapses from the phase detection, the piston rod57A is advanced from the fitting/releasing hydraulic cylinder57, the pinion gear15is moved in the engaging direction A, and the pinion gear15and the wheel gear16are brought into contact with each other. The forward rotation operation by the forward rotation hydraulic cylinder51is resumed after a time T12elapses from the phase detection, and the forward rotation operation by the forward rotation hydraulic cylinder51is performed until the time T5elapses. When the forward rotation operation is performed until the time T5elapses, the engagement operation is completed.

In a case where the first proximity switch61is not switched for the time T6in the forward rotation operation that is performed from a time point II after the time T12elapses, operation at a time point III is performed again, and the operation is repeated until the engagement is completed.

After the engagement operation is completed, the movement of the pinion gear15in the direction A is stopped as with the normal state. After the time T13elapses from the engagement detection, the pinion shaft14is rotated by the turning motor11to start turning.

As described above, even if the engagement operation is stopped halfway, the turning device1makes it possible to automatically restore the engagement operation. This makes it possible to save the labor of an operator of the turning device1, and to improve convenience.

In addition, the pinion gear15and the wheel gear16are gradually rotated at the low speed until the engagement thereof is completed. Therefore, even if the pinion gear15and the wheel gear16do not engage with each other halfway, both of the pinion gear15and the wheel gear16are not damaged. Accordingly, the pinion gear15and the wheel gear16are hardly deteriorated with time.

As illustrated inFIG. 7A, the pinion gear15has the fixed thickness up to an end of the thread. In a case where the end of the thread is made thin as with a conventional example illustrated inFIG. 7B, a thin part is brought into contact with the wheel gear16, and the front end of the thread of the pinion gear15is brought into contact with a side surface of the tooth profile of the wheel gear and does not engage with the wheel gear because the thin part has a pitch different from other parts, in some cases. In contrast, in one or more embodiments of the present invention, the thin part is not provided, which makes it possible to facilitate the engagement of the pinion gear15and the wheel gear16. Further, it is possible to cause the pinion gear15and the wheel gear16to be hardly deteriorated with time.

Hereinbefore, the present invention has been described with reference to various embodiments; however, the configurations described in the above-described embodiments may be selected or appropriately modified without departing from the scope of the present invention.

In one or more embodiments, the convex parts33B and the concave parts33C are provided on the forward rotating body31. Alternatively, the convex parts33B and the concave parts33C may be provided not on the forward rotating body31but on the reverse rotating body33, and the phase may be detected by the detection sensor. This makes it possible to downsize the turning device1.

In one or more embodiments, the forward rotating body31and the reverse rotating body33may not face each other. The convex parts and the concave parts may be provided also on the forward rotating body31and the phase may be detected by other proximity switch.

The forward rotating body31may have a shape other than the disc shape according to the shape of the gearbox70and the position of the first proximity switch61in the gearbox70as long as the forward rotating body31can rotate the rotary shaft forward. Likewise, the reverse rotating body33may have a shape other than the disc shape as long as the reverse rotating body33can rotate the rotary shaft reversely. The shape of the forward rotating body31and the shape of the reverse rotating body33may be different from each other.

REFERENCE SIGNS LIST