JP2012110102A - Shaft seal device of rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shaft seal device of a rotary electric machine which seals a cooling medium in the machine even if a casing of a seal ring is displaced by increasing an internal pressure of the machine.SOLUTION: A shaft seal device 10 according to an embodiment comprises: a machine internal seal ring 11; a machine external seal ring 12; a casing 13; and a center spring 14. The machine internal seal ring 11 is attached to a shaft 2 so as to form a first clearance C1 and has an inward rim 111 at an outer peripheral part. The machine external seal ring 12 is attached to the shaft 2 so as to form a second clearance C2 and has an outward rim 121 at an outer peripheral part. The casing 13 encloses outer peripheries of the inward rim 111 and the outward rim 121. The casing 13 makes line contacts with at least the machine external seal ring 12. A seal oil L flows from a gap G to an inner side and an outer side of the machine through the first clearance C1 and the second clearance C2.

Description

  Embodiments described herein relate generally to a shaft seal device for a rotating electrical machine that uses a gas as a cooling medium.

  In order to improve energy conversion efficiency, the rotating electrical machine cools the rotor and stator in the machine. At this time, hydrogen gas is used as a cooling medium. In order to contain the cooling medium in the machine, a shaft seal device is installed between the rotor shaft and the frame. The shaft seal device includes a seal ring that is attached to the shaft with a gap therebetween and has an axial gap for supplying seal oil to the gap, and a seal casing that covers the seal ring.

  The seal ring is restrained by the seal casing from moving along the axial direction of the shaft. The seal oil is supplied between the seal casing and the seal ring at a pressure higher than the gas pressure inside the machine, passes through the gap of the seal ring, and flows out to the gap between the seal ring and the shaft. As the seal oil supplied to the gap flows out along the outer peripheral surface of the shaft to the inside and outside of the rotating electric machine, the hydrogen gas of the cooling medium is sealed in the machine.

JP 2008-301575 A JP 2006-345697 A JP 2006-345696 A

  In order to reduce the environmental load caused by the rotating electrical machine, it is required to increase the energy conversion efficiency. In the case of a rotating electrical machine that uses hydrogen as a cooling medium, it is conceivable to increase the capacity of the hydrogen cooler or reduce loss in order to increase energy conversion efficiency. One way to reduce the loss at this time is to increase the gas pressure in the rotating electrical machine. However, in order to increase the gas pressure, various structural studies are required, such as securing the pressure resistance of the frame.

  When the pressure in the machine is increased, the frame covering the rotor is expected to swell slightly due to the internal pressure. At this time, if the seal casing is displaced to the outside of the machine and the gap between the seal ring and the shaft changes, the flow of the seal oil may change and the sealing performance may deteriorate. In order to increase the rigidity of the frame and the seal casing so that the seal casing is not displaced, it is necessary to increase the thickness of the member itself or to improve the structure. However, in either case, this results in a bulky frame and seal casing.

  Further, since the seal ring and the seal casing cannot be replaced while the rotary electric machine is in operation, it is desirable to avoid increasing the number of parts or adopting a complicated structure as much as possible.

  Therefore, the present invention provides a shaft seal device for a rotating electrical machine that seals a cooling medium in the machine even when the casing of the seal ring is displaced by increasing the machine pressure.

  A shaft seal device according to an embodiment is a shaft seal measure that is provided between a shaft and a frame of a rotating electric machine and encloses a cooling medium in a machine, and includes an inside seal ring, an outside seal ring, a casing, A center spring. The in-machine seal ring is mounted with a first clearance over the entire circumference of the outer peripheral surface of the shaft, and has an inward rim that protrudes inward of the in-machine. The outer seal ring has a second clearance all around the outer peripheral surface of the shaft and is mounted on the outer side with a gap with respect to the inner seal ring. Have. The casing is supported by the frame and surrounds the outer periphery of the inward rim and the outward rim and is supplied with seal oil. The center spring abuts on the inner seal ring and the outer seal ring from the outer peripheral side, and widens the gap and acts in a direction to tighten the inner seal ring and the outer seal ring toward the shaft. The casing seals the seal oil by making line contact with at least one of the machine inner seal ring and the machine outer seal ring along a circle centered on the shaft center, and seals the machine inner seal ring and machine. The outer seal ring allows seal oil to flow from the gap to the inside and outside of the machine through the first clearance and the second clearance.

Sectional drawing which shows the edge part of the rotary electric machine with which the shaft seal apparatus of 1st Embodiment was mounted | worn. Sectional drawing of the shaft-seal apparatus shown in FIG. Sectional drawing of the state in which the pressure was applied to the shaft seal device shown in FIG. Sectional drawing which shows the shaft seal apparatus of 2nd Embodiment. Sectional drawing of the state in which the pressure was applied to the shaft seal device shown in FIG. Sectional drawing which shows the shaft-seal apparatus of 3rd Embodiment. Sectional drawing which shows the shaft-seal apparatus of 4th Embodiment. FIG. 8 is a cross-sectional view showing a state in which pressure is applied to the shaft seal device shown in FIG. Sectional drawing which shows the shaft-seal apparatus of 5th Embodiment. FIG. 10 is a cross-sectional view showing a state in which pressure is applied to the shaft seal device shown in FIG. 9 from the inside of the machine. Sectional drawing which shows the shaft-seal apparatus of 6th Embodiment. FIG. 12 is a cross-sectional view showing a state in which pressure is applied to the shaft seal device shown in FIG.

  The shaft seal device 10 of the first embodiment will be described with reference to FIGS. 1 to 3. As shown in FIG. 1, the shaft seal device 10 is installed between a rotor shaft 2 of the rotating electrical machine 1 and a frame 3 that houses a stator disposed on the outer periphery of the rotor. The rotary electric machine 1 circulates hydrogen gas as a cooling medium G in the machine in order to cool the rotor and stator coils. The shaft seal device 10 is provided to enclose the cooling medium G in the machine, and is attached to the inner side of the machine than the bearing 4 that supports the shaft 2. In this specification, based on the axis of the shaft 2, the side near the axis is “inner circumference”, the side far from the axis is “outer circumference”, the center along the shaft 2 is “inside”, the shaft The side closer to the end of 2 is called “the outside”.

  As shown in FIG. 2, the shaft seal device 10 includes an inside seal ring 11, an outside seal ring 12, a casing 13, and a center spring 14. The in-machine seal ring 11 is mounted with a fixed first clearance C1 around the entire outer periphery of the shaft 2, and has an inward rim 111 projecting inward of the in-machine. The outboard seal ring 12 is mounted with a constant second clearance C2 around the entire outer periphery of the shaft 2, and has an outward rim 121 protruding outward from the outboard. The outboard seal ring 12 is attached to the outboard side with a gap S with respect to the inboard seal ring 11. The in-machine seal ring 11 and the out-of-machine seal ring 12 are each formed by being divided into half circumferences.

  The casing 13 is supported on the frame 3 by a partition wall 130 and surrounds the outer periphery of the inward rim 111 and the outward rim 121. Seal oil L is supplied into the casing 13. The casing 13 includes an inboard lip 131 and an outboard lip 132. The inboard lip 131 wraps around the inward rim 111 and extends between the inward rim 111 and the shaft 2. The outboard lip 132 wraps around the outward rim 121 and extends between the outward rim 121 and the shaft 2.

  The center spring 14 is mounted in a groove formed by tapered surfaces 112 and 122 formed at the corners of the outer peripheral portions of the inner seal ring 11 and the outer seal ring 12 adjacent to each other. The center spring 14 abuts on the tapered surface 112 of the in-machine seal ring 11 and the tapered surface 122 of the out-of-machine seal ring 12, respectively, to widen the gap S and to cause the in-machine seal ring 11 and the out-of-machine seal ring 12 to shaft. Acts to tighten towards 2.

  The casing 13 is in line contact with at least one of the inboard seal ring 11 and the outboard seal ring 12 along a circle centered on the axis of the shaft 2. In the present embodiment, the casing 13 is in line contact with both the inboard seal ring 11 and the outboard seal ring 12 as shown in FIG. Since the inner seal ring 11 and the casing 13 are in line contact, the end surface 111A of the inward rim 111 of the inner seal ring 11 is formed as a curved surface that swells toward the inner side, and is in line contact with the inner wall 13A of the casing 13. To do. Further, since the outer seal ring 12 and the casing 13 are in line contact with each other, the front end surface 132A of the outer lip 132 of the casing 13 is formed in a curved surface that swells toward the inner side of the machine. Line contact is made with the side surface 123 facing outward.

  The shaft seal device 10 of this embodiment further includes an outboard spring 15 as shown in FIG. The outboard spring 15 is mounted so as to come into contact with a tapered surface 124 formed at an outer peripheral corner of the outward rim 121 of the outboard seal ring 12 and an inner wall 13B of the casing 13. The outboard spring 15 biases the outboard seal ring 12 toward the inside of the machine and biases it toward the outer peripheral surface of the shaft 2.

  The shaft seal device 10 configured as described above makes line contact at each of the end surface 111A of the inward rim 111 and the inner wall 13A of the casing 13, the front end surface 132A of the outboard lip 132, and the side surface 123 of the outboard seal ring 12. Therefore, the seal oil L supplied into the casing 13 is sealed. Further, the in-machine seal ring 11 and the out-of-machine seal ring 12 cause the seal oil L to flow from the gap S to the first clearance C1 and the second clearance C2, respectively.

  When the pressure inside the machine is increased to increase the cooling capacity of the hydrogen gas that is the cooling medium G, that is, when the density of the hydrogen gas is increased, the frame 3 is deformed or the partition wall 130 that supports the casing 13 is deformed to the outside of the machine like a diaphragm. To do. As a result, the casing 13 is expected to be displaced so as to roll outwardly with the outer peripheral side of the casing 13 as a fulcrum as shown in FIG.

  In the shaft seal device 10 according to the first embodiment, since the end surface 111A of the inward rim 111 and the front end surface 132A of the outboard lip 132 are both formed into curved surfaces that swell inward, the frame 3 and the casing 13 are displaced. Even in this case, the in-machine seal ring 11 and the out-of-machine seal ring 12 are not twisted along with the casing 13, and the in-machine seal ring 11 and the casing 13 and the out-of-machine seal ring 12 and the casing 13 are lined up. Maintain contact.

  The supply pressure of the seal oil L and the tightening force of the center spring 14 and the outboard spring 15 are balanced, so that the gap S, the first clearance C1, and the second clearance C2 are increased before the in-machine pressure is increased. Maintained in the same state. That is, even if the pressure of the cooling medium G is increased, the shaft seal device 10 seals the cooling medium G in the machine.

  When the casing 13 is displaced so as to be twisted from the state shown in FIG. 2 to the state shown in FIG. 3, the front end surface 131 </ b> A of the inboard lip 131 approaches the side surface 113 facing the inboard side of the inboard seal ring 11. Therefore, the front end surface 131A of the inboard side lip 131 is formed in a state of being separated from the side surface 113 of the inboard side seal ring 11 in consideration of the amount of deformation.

  In addition, since the pressure of the cooling medium G acts on the inside of the rotating electrical machine 1, the machine inside seal ring 11 receives pressure on the machine outside. At this time, in the case of the shaft seal device 10 of the first embodiment, an outboard spring 15 is provided. Accordingly, the end surface 111A of the inward rim 111 of the inboard seal ring 11 is pressed against the inner wall 13A of the casing 13 by the outboard spring 15, and the line contact state is maintained. Further, the outboard spring 15 prevents the inner peripheral surface 121B of the outward rim 121 of the outboard seal ring 12 from opening outward.

  Since the outside of the shaft seal device 10 is at atmospheric pressure, if the pressure of the seal oil L flowing from the gap S to the first clearance C1 or the second clearance C2 is maintained, the outside seal ring 12 is maintained. There is no need for a perfect seal between the casing 13 and the casing 13. Instead of making line contact between the outside seal ring 12 and the casing 13, a flexible packing or gasket may be attached.

  The end surface 111A of the inward rim 111 of the in-machine seal ring 11 and the front end surface 132A of the out-of-machine lip 132 of the casing 13 are formed in a curved surface having a constant curvature, or the frame 3 and the partition wall 130 are deformed in accordance with the pressure change in the machine. Whether to form a curved surface with a changed curvature is appropriately selected according to the specifications and operating conditions of the rotating electrical machine 1. That is, the dimensions of each part of the shaft seal device 10 are determined so that the machine inner seal ring 11 and the machine outer seal ring 12 of the shaft seal device 10 are in ideal positions while the rotary electric machine 1 is in rated operation. The

  The shaft seal devices 10 of the second to sixth embodiments will be described below with reference to the drawings. In the shaft seal device 10 of each embodiment, configurations having the same functions as those of the shaft seal device 10 of the first embodiment are denoted by the same reference numerals in the drawings, and description thereof is omitted. The configuration of the rotating electrical machine 1 around the shaft seal device 10 takes into account the contents described in the first embodiment and FIG.

  The shaft seal device 10 of the second embodiment will be described with reference to FIGS. 4 and 5. In the shaft seal device 10 shown in FIGS. 4 and 5, the end surface 111 </ b> A of the inward rim 111 of the inboard seal ring 11 is formed flat so as not to contact the inner wall of the inner wall 13 </ b> A of the casing 13. The front end surface 131A of the in-machine lip 131 of the casing 13 is formed in a curved surface that swells to the outside of the machine, and is in line contact with the in-machine side surface 113 of the in-machine seal ring 11. Further, the end surface 121A of the outward rim 121 of the outer seal ring 12 is formed in a curved surface that swells to the outer side, and is in line contact with the inner wall 13B of the casing 13. The front end surface 132A of the outboard lip 132 of the casing 13 is formed flat and does not contact the side surface 123 of the outboard seal ring 12 even when the casing 13 is displaced due to internal pressure. Other configurations are the same as those of the shaft seal device 10 of the first embodiment.

  In the shaft seal device 10, both the front end surface 131 </ b> A of the inboard lip 131 and the end surface 121 </ b> A of the outward rim 121 of the outboard seal ring 12 are formed into curved surfaces that bulge outward. Therefore, even when the casing 13 is displaced from the state shown in FIG. 4 as shown in FIG. 5 by increasing the pressure in the machine in order to increase the cooling efficiency, the machine inner seal ring 11 and the machine outer seal ring are accompanied by the casing 13. 12 cannot be twisted. The state where the in-machine seal ring 11 and the casing 13 and the out-of-machine seal ring 12 and the casing 13 are in line contact with each other is maintained. Further, since the supply pressure of the seal oil L and the tightening force of the center spring 14 and the outboard spring 15 are balanced, the gap S, the first clearance C1, and the second clearance C2 are the same as before the in-machine pressure is increased. Maintained in a state.

  In the second embodiment, as shown in FIGS. 4 and 5, the front end surface 132A of the outboard lip 132 is separated from the side surface 123 of the outboard seal ring 12 both before and after increasing the inboard pressure. Yes, the end surface 121A of the outward rim 121 of the outboard seal ring 12 is in a line contact with the inner wall 13B of the casing 13. Before the in-machine pressure is increased, the end surface 121A of the outward rim 121 of the outboard seal ring 12 is connected to the inner wall 13B of the casing 13 while the front end surface 132A of the outboard lip 132 is in contact with the side surface 123 of the outboard seal ring 12. After the internal pressure is increased, the end surface 132A of the outboard lip 132 is separated from the side surface 123 of the outboard seal ring 12, and the end surface of the outward rim 121 of the outboard seal ring 12 is maintained. 121A may be configured to be in line contact with the inner wall 13B of the casing 13, respectively.

  Further, in the second embodiment, as shown in FIGS. 4 and 5, the front end surface 131 </ b> A of the inboard lip 131 contacts the side surface 113 of the inboard seal ring 11 before and after the in-machine pressure is increased. In this state, the end surface 111 </ b> A of the inward rim 111 of the inboard seal ring 11 is separated from the inner wall 13 </ b> A of the casing 13. Before increasing the in-machine pressure, the front end surface 131A of the inboard lip 131 is separated from the side surface 113 of the inboard seal ring 11, and the end surface 111A of the inward rim 111 of the inboard seal ring 11 is attached to the inner wall 13A of the casing 13. After the in-machine pressure is increased, the tip surface 131A of the inboard lip 131 is in line contact with the side surface 113 of the inboard seal ring 11, and the inward rim 111 of the inboard seal ring 11 is in contact. The end surface 111 </ b> A may be configured to be in line contact with the inner wall 13 </ b> A of the casing 13.

  The shaft seal device 10 of the third embodiment will be described with reference to FIG. In the shaft seal device 10 shown in FIG. 6, the in-machine seal ring 11 and the out-of-machine seal ring 12 have the same configuration as the in-machine seal ring 11 and the out-of-machine seal ring 12 of the first embodiment. The shaft seal device 10 has a first elastic member 133 that contacts the side surface 113 of the inboard seal ring 11 at the tip of the inboard lip 131, and the inner periphery of the outward rim 121 of the outboard seal ring 12. The point which has the 2nd elastic member 134 which contacts the surface 121B on the outer peripheral surface 132B of the outboard lip 132 is different from the first embodiment.

  In the shaft seal device 10 configured as described above, the end surface 111A formed on the curved surface of the inward rim 111 of the inboard seal ring 11 is in line contact with the inner wall 13A of the casing 13, and the outboard spring 15 is in the machine. The inner seal ring 11 and the outer seal ring 12 are urged toward the inner side. If the casing 13 is displaced as in the first embodiment or the second embodiment when the in-machine pressure is increased, the first elastic member 133 is pressed against the side surface 113 of the in-machine seal ring 11 and flattened. The second elastic member 134 is pressed and flattened against the inner peripheral surface 121B of the outward rim 121 of the outboard seal ring 12.

  Even if the casing 13 is displaced, the in-machine seal ring 11 and the out-of-machine seal ring 12 maintain the gap S, the first clearance C1, and the second clearance C2 as before the in-machine pressure increases. Further, when the supply pressure of the seal oil L is increased in response to the increase of the in-machine pressure, the first elastic member 133 and the second elastic member 134 are more strongly inward than the in-machine pressure. The seal ring 11 and the outside seal ring 12 are pressed against each other. The tightness between the in-machine seal ring 11 and the casing 13 and between the in-machine seal ring 12 and the casing 13 is also enhanced.

  As the first elastic member 133 and the second elastic member 134, neoprene rubber, urethane rubber, silicone rubber, or the like is employed. Since the amount of flattening of the first elastic member 133 and the second elastic member 134 due to the displacement of the casing 13 is very small, a gasket can be used instead of an elastic member if the required elasticity and sealing properties are satisfied. Or packing may be used.

  The supply pressure of the seal oil L is set higher than the in-machine pressure. Accordingly, when the in-machine pressure is increased, the differential pressure between the pressure of the seal oil L inside the casing 13 and the atmospheric pressure outside the machine of the casing 13 also increases. In such a case, in order to assist the sealing function of the second elastic member 134, a backup ring is mounted on the atmospheric pressure side together with the second elastic member 134.

  A shaft seal device 10 according to the fourth embodiment will be described with reference to FIGS. 7 and 8. In the shaft seal device 10 shown in FIGS. 7 and 8, the end surface 111 </ b> A of the inward rim 111 of the inboard seal ring 11 is formed in a curved surface and is in line contact with the inner wall 13 </ b> A of the casing 13. Further, the end surface 121A of the outward rim 121 of the outboard seal ring 12 is also formed in a curved surface and is in line contact with the inner wall 13B of the casing 13. The front end surface 131A of the inboard lip 131 and the front end surface 132A of the outboard lip 132 of the casing 13 are in a state of being separated from the side surface 113 of the inboard seal ring 11 and the side surface 123 of the outboard seal ring 12.

  As shown in FIGS. 7 and 8, the shaft seal device 10 further includes an in-machine spring 16. The in-machine spring 16 is mounted in a groove 114 formed in the outer peripheral portion of the in-machine seal ring 11 and biases the in-machine seal ring 11 toward the outer peripheral surface of the shaft 2. In the shaft seal device 10 of the fourth embodiment, the front end surface 131A of the inboard lip 131 and the front end surface 132A of the outboard lip 132 of the casing 13 are respectively the side surface 113 of the inboard seal ring 11 and the outboard seal ring 12. It is separated from the side surface 123.

  The pressure of the cooling medium G is applied to the machine inner seal ring 11 facing the machine. When the inboard lip 131 is separated from the side surface 113 of the inboard seal ring 11, the inner circumferential surface 111 B of the inward rim 111 receives the pressure of the cooling medium G, and the inboard seal ring 11 is separated from the outer peripheral surface of the shaft 2. It is urged in the direction of separating, that is, the direction of expanding the first clearance C1.

  At this time, since the shaft seal device 10 of the fourth embodiment includes the in-machine spring 16, even if the in-machine pressure is increased, the first seal ring 11 has the same size as before the in-machine pressure is increased. The clearance C1 is maintained. Further, since the inboard spring 16 does not contact the inner wall 13A of the casing 13, the end surface 111A formed on the curved surface of the inward rim 111 of the inboard seal ring 11 does not act in the direction of pulling away from the inner wall 13A of the casing 13.

  In the shaft seal device 10 configured as described above, the supply pressure of the seal oil L and the tightening force of the center spring 14, the outboard spring 15 and the outboard spring 16 are balanced, so that the gap S and the first The clearance C1 and the second clearance C2 are maintained in the same state as before the in-machine pressure is increased.

  A shaft seal device 10 according to a fifth embodiment will be described with reference to FIGS. 9 and 10. In the shaft seal device 10 shown in FIG. 9, the end surface 111 </ b> A of the inward rim 111 of the inboard seal ring 11 is formed in a curved surface and is in contact with the inner wall 13 </ b> A of the casing 13. Both the front end surface 131A of the inboard lip 131 and the front end surface 132A of the outboard lip 132 are formed into curved surfaces. The front end surface 131 A of the inboard lip 131 is in line contact with the side surface 113 of the inboard side seal ring 11, and the front end surface 132 A of the outboard side lip 132 is in line contact with the side surface 123 of the outboard side seal ring 12.

  As shown in FIGS. 9 and 10, the casing 13 includes an inner slide mechanism 17 that displaces the front end surface 131 </ b> A of the inboard lip 131 relative to the casing 13 in a direction along the axis of the shaft 2. The inner slide mechanism 17 includes a sliding ring 171 formed with an in-machine lip 131, a connector 172 that holds the sliding ring 171 on the casing 13, and the sliding ring 171 on the side surface 113 of the in-machine seal ring 11. And a spring 173 for pushing out. The inner slide mechanism 17 is designed to maintain hermeticity in a portion where the slide ring 171 slides with respect to the casing 13.

  The couplers 172 are arranged at several locations along the circumferential direction of the casing 13 so that the sliding ring 171 is held on the inner periphery of the casing 13 that is divided together with the frame 3 when the rotating electrical machine is disassembled. That's fine. The spring 173 is configured to push the sliding ring 171 toward the inboard seal ring 11 with an equal force. Therefore, it may be divided into several places and may be formed in a continuous arc according to the size of the casing 13 being divided. Alternatively, the spring 173 may be attached between the sliding ring 171 and the connector 172.

  In the fifth embodiment, the casing 13 is supported by a fulcrum at a position P1 on the outer side of the machine outer seal ring 12 and on the outer periphery of the casing 13. Therefore, when the pressure inside the machine increases, the casing 13 is displaced with the position P1 as a fulcrum as shown in FIG. Tilt to approach the shaft 2.

  As shown in FIG. 10, even if the end surface 111A of the inward rim 111 of the inboard seal ring 11 is separated from the inner wall 13A of the casing 13 due to the displacement of the casing 13 due to the in-machine pressure, the shaft seal device of the fifth embodiment is Since the inner slide mechanism 17 is provided, the state where the front end surface 131A of the inboard lip 131 is in contact with the side surface 113 of the inboard seal ring 11 is maintained.

  As shown in FIG. 10, even when the in-machine pressure is increased, the seal oil L does not flow out between the in-machine seal ring 11 and the casing 13 and the out-of-machine seal ring 12 and the casing 13. Accordingly, the supply pressure of the seal oil L, the tightening force of the center spring 14 and the outboard spring 15 and the in-machine pressure are balanced, so that the gap S, the first clearance C1 and the second clearance C2 are as shown in FIG. Is maintained in the same state as before the in-machine pressure increases. When the seal oil L flows from the gap S through the first clearance C1 or the second clearance C2 to the inside of the machine and the outside of the machine, the shaft seal device 10 seals the cooling medium G in the machine.

  A shaft seal device 10 according to the sixth embodiment will be described with reference to FIGS. 11 and 12. In the shaft seal device 10 shown in FIG. 11, the end surface 111 </ b> A of the inward rim 111 of the inboard seal ring 11 is formed in a curved surface and is in line contact with the inner wall 13 </ b> A of the casing 13. The front end surface 131 </ b> A of the in-machine lip 131 is separated from the side surface 113 of the in-machine seal ring 11. The front end surface 132A of the outboard lip 132 is formed in a curved surface and is in line contact with the side surface 123 of the outboard seal ring 12. Further, the distance from the inner peripheral surface 121B of the outward rim 121 to the outer peripheral surface 132B of the outboard lip 132 is formed larger than the distance from the inner peripheral surface 111B of the inward rim 111 to the outer peripheral surface 131B of the inboard lip 131. Yes.

  The shaft seal device 10 of this embodiment includes an outer slide mechanism 18 that displaces the front end surface 132A of the machine-side lip 132 with respect to the casing 13 in the direction along the axis of the shaft 2 as shown in FIGS. ing. The outer slide mechanism 18 includes a sliding ring 181 formed with an outboard lip 132, a connector 182 that holds the sliding ring 181 on the casing 13, and the sliding ring 181 on the side surface 123 of the outboard seal ring 12. And a spring 183 for pushing out. Similar to the inner slide mechanism 17 in the fifth embodiment, the outer slide mechanism 18 is designed to maintain hermeticity in a portion where the slide ring 181 slides with respect to the casing 13.

  The couplers 182 are arranged at several locations along the circumferential direction of the casing 13 so that the sliding ring 181 is held on the inner periphery of the casing 13 that is divided together with the frame 3 when the rotating electrical machine is disassembled. That's fine. The spring 183 is configured to push the sliding ring 181 toward the outboard seal ring 12 with an equal force. Therefore, it may be divided and arranged in several places, or may be formed in a continuous arc according to the size into which the casing 13 is divided. Alternatively, the spring 183 may be mounted between the sliding ring 181 and the connector 182.

  In the shaft seal device 10 according to the sixth embodiment, the casing 13 is supported by a position P2 on the inner side of the machine than the center spring 14 and on the outer periphery of the casing 13 as a fulcrum. Therefore, when the pressure inside the machine increases, the casing 13 is displaced from the position P2 as a fulcrum as shown in FIG. Tilt away from 2.

  At this time, since the front end surface 131A of the inboard lip 131 is separated from the side surface 113 of the inboard seal ring 11, the end surface 111A of the inward rim 111 of the inboard seal ring 11 is in line contact with the inner wall 13A of the casing 13. Maintained. Further, the inner peripheral surface 121B of the outward rim 121 of the outer seal ring 12 is sufficiently large so that it does not contact the outer peripheral surface 132B of the outer lip 132 even when the casing 13 is tilted by the internal pressure as shown in FIG. Away. Therefore, the outboard seal ring 12 maintains the second clearance C2 constant with respect to the shaft 2.

  The casing 13 is inclined with respect to the in-machine seal ring 11 and the out-of-machine seal ring 12 so that the end surface 111A of the inward rim 111 of the in-machine seal ring 11 comes into contact with the inner wall 13A of the casing 13 from the position outside the machine. The distance to the position where the front end surface 132A of the lip 132 is in line contact with the side surface 123 of the outer seal ring 12 is shortened. Since the shaft seal device 10 includes the outer slide mechanism 18, the front end surface 132 </ b> A of the outboard lip 132 is maintained in line contact with the side surface 123 of the outboard seal ring 12.

  Even when the in-machine pressure is increased, the seal oil L does not flow out between the in-machine seal ring 11 and the casing and between the in-machine seal ring 12 and the casing 13 as shown in FIG. Accordingly, since the supply pressure of the seal oil L, the tightening force of the center spring 14 and the outboard spring 15 and the in-machine pressure of the rotating electrical machine are balanced, the gap S, the first clearance C1, and the second clearance C2 are 11 is maintained in the same state as before the in-machine pressure shown in FIG. Then, when the seal oil L flows from the gap S to the side that does not pass through the first clearance C1 or the second clearance C2 and the outside of the machine, the shaft seal device 10 seals the cooling medium G in the machine.

  As described above, according to the shaft seal device 10 of the first to sixth embodiments, even when the in-machine pressure of the rotating electrical machine is increased in order to enhance the ability to cool the rotor and stator coils, the inside of the machine The seal ring 11 and the outboard seal ring 12 are maintained in the same state as before the in-machine pressure is increased. Since the gap S as the circulation path of the seal oil L and the first clearance C1 and the second clearance C2 are kept constant without being changed before and after increasing the in-machine pressure, the shaft seal device 10 is Even when the in-machine pressure is increased, the cooling medium is sealed in the apparatus in the same manner as when the in-machine pressure is low. A rotating electrical machine that employs the shaft seal device 10 can improve power generation efficiency and reduce environmental load by efficiently cooling the rotor and stator coils by increasing the in-machine pressure during rated operation.

  The respective configurations of the shaft seal devices 10 of the first to sixth embodiments described above may be appropriately recombined as long as no structural contradiction occurs. For example, the first elastic member 133 and the second elastic member 134 of the shaft seal device 10 of the third embodiment are respectively the same part of the shaft seal device 10 of the first and fourth embodiments, or the second Between the end surface 111A of the inward rim 111 of the inboard seal ring 11 of the shaft seal device 10 of the embodiment and the inner wall 13A of the casing 13 and the inner peripheral surface 121B of the outward rim 121 of the outboard seal ring 12 and the outboard lip 132 of the casing. Each of the outer peripheral surfaces 132B may be employed.

  Also, in the shaft seal device 10 of the first to sixth embodiments, the inner walls 13A and 13B of the casing 13 are all formed flat, whereas the casing 13 is displaced according to the change in the in-machine pressure. In this case, each end face has a shape that makes line contact with the end face 111A formed on the curved surface of the inward rim 111 of the inboard seal ring 11 and the end face 121A formed on the curved face of the outward rim 121 of the outboard seal ring 12. It may be formed in a gentle concave curved surface having a larger radius of curvature than 111A and 121A.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the spirit and scope of the invention, and in the invention described in the claims and equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Rotary electric machine, 2 ... Shaft, 3 ... Frame, 10 ... Shaft seal device, 11 ... Machine inner side seal ring, 111 ... Inward rim, 111A ... End surface, 111B ... Inner peripheral surface, 113 ... Side surface, 114 ... Groove, 12 ... Outside seal ring, 121 ... Outward rim, 121A ... End face, 121B ... Inner peripheral surface, 123 ... Side, 13 ... Case, 13A ... Inner wall (inside the machine), 13B ... Inner wall (outside the machine), 131 ... machine Inner lip, 131A ... tip surface, 131B ... outer peripheral surface, 132 ... outer lip, 132A ... tip surface, 132B ... outer peripheral surface, 133 ... first elastic member, 14 ... center spring, 15 ... outer spring, 16 ... In-machine spring, 17 ... inner slide mechanism, 18 ... outer slide mechanism, G ... cooling medium, C1 ... first clearance, C2 ... second clearance, S ... gap, L Seal oil, P1 ... position on the outer circumference than the outboard side and the casing than the outboard seal ring, the position of the outer periphery than the inboard side and the casing than P2 ... center spring.

Claims (15)

A shaft seal device that is installed between a shaft and a frame of a rotating electric machine and encloses a cooling medium in the machine,
An in-machine seal ring having an inward rim mounted on the outer periphery of the shaft with a first clearance around the entire circumference of the outer periphery of the shaft;
An outboard seal ring having a second clearance over the entire circumference of the outer peripheral surface of the shaft and having an outward rim mounted on the outside of the machine with a gap with respect to the inboard seal ring and projecting outward from the machine. When,
A casing that is supported by the frame and that surrounds the outer periphery of the inward rim and the outward rim and is supplied with sealing oil;
A center spring that contacts the inner seal ring and the outer seal ring from the outer peripheral side to widen the gap and acts in a direction to tighten the inner seal ring and the outer seal ring toward the shaft;
With
The casing seals the seal oil by making line contact with at least one of the inner seal ring and the outer seal ring along a circle centered on the shaft axis.
The shaft seal device, wherein the inner seal ring and the outer seal ring distribute the seal oil from the gap to the first clearance and the second clearance. 2. The shaft seal device according to claim 1, wherein an end surface of the inward rim is formed in a curved surface that comes into line contact with an inner wall of the casing. 2. The shaft seal device according to claim 1, wherein an end surface of the outward rim is formed in a curved surface that is in line contact with an inner wall of the casing. The casing has an outboard lip extending between the outward rim and the outer peripheral surface of the shaft, and a tip surface of the outboard lip is in line contact with a side surface of the outboard seal ring facing the outboard side. The shaft seal device according to claim 1, wherein the shaft seal device is formed on a curved surface. The casing has an inboard lip extending between the inward rim and the outer peripheral surface of the shaft, and a front end surface of the inboard lip makes line contact with a side surface of the inboard seal ring facing the inboard side. The shaft seal device according to claim 1, wherein the shaft seal device is formed in a curved surface. The casing has an inboard lip extending between the inward rim and the outer peripheral surface of the shaft and having a groove formed at the tip, and an elastic member that contacts an inward side surface of the inboard seal ring. The shaft seal device according to claim 2, wherein the shaft seal device is attached to the groove. The casing has an inboard lip extending between the inward rim and the outer peripheral surface of the shaft, and a front end surface of the inboard lip is separated from a side of the inboard seal ring facing the inboard side. The shaft seal device according to claim 2, wherein: An outboard spring is further provided that abuts the outer periphery of the outward rim of the outboard seal ring and the inner wall of the casing and biases the outboard seal ring toward the inboard and the outer peripheral surface of the shaft. Item 3. A shaft seal device according to item 2. The shaft seal device according to claim 8, wherein a tightening force of the outboard spring is smaller than a tightening force of the center spring. The apparatus further comprises an in-machine spring that is mounted in a groove formed in an outer peripheral portion of the inward rim of the in-machine seal ring and biases the in-machine seal ring toward the outer peripheral surface of the shaft. 3. The shaft seal device described in 3. The casing includes an inner slide mechanism for displacing the tip surface in a direction along the axis of the shaft in order to maintain a state where the tip surface of the inner lip is in line contact with a side surface of the inner seal ring. The shaft seal device according to claim 5, wherein the shaft seal device is provided. The casing includes an outer slide mechanism for displacing the tip surface in a direction along the axis of the shaft in order to maintain a state in which the tip surface of the outer lip is in line contact with a side surface of the outer seal ring. The shaft seal device according to claim 4, wherein the shaft seal device is provided. 2. The shaft seal device according to claim 1, wherein the casing is supported by a fulcrum at a position on the outer side of the machine outer seal ring and on the outer periphery of the casing. 2. The shaft seal device according to claim 1, wherein the casing is supported by a fulcrum at an inner side of the center spring and an outer periphery of the casing. The distance from the inner peripheral surface of the outward rim to the outer peripheral surface of the outboard lip is formed larger than the distance from the inner peripheral surface of the inward rim to the outer peripheral surface of the inboard lip. Item 15. A shaft seal device according to Item 14.

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