Patent Application
20120285150
The present invention relates to a power generating apparatus of a renewable energy type which transmits rotation energy of a rotor via a hydraulic transmission that is a combination of a hydraulic pump and a hydraulic motor. The power generating apparatus of the renewable energy type generates power from a renewable energy such as wind, tidal current, ocean current and river current and, for instance, includes a wind turbine generator, a tidal generator, an ocean current generator, a river current generator or the like.
To improve power generation efficiency, it is desired to increase the size of the power generating apparatus of the renewable energy type. Particularly, wind turbine generators installed offshore are expensive to construct in comparison to those installed onshore and thus, it is desired to improve power generation efficiency by increasing the size of the wind turbine generator so as to improve profitability.
In recent years, from a perspective of preserving the environment, it is becoming popular to use a power generating apparatus of a renewable energy type such as a wind turbine generator utilizing wind power and a renewable energy type turbine generator such as a tidal current generator utilizing tidal. In the power generating apparatus of the renewable energy type, a motion energy of the wind, the tidal current, the ocean current or the river current is converted into the rotation energy of the rotor and the rotation energy of the rotor is converted into electric power by the generator.
In this type of the power generating apparatus of the renewable energy type, the rotation speed of the rotor is small compared to a rated speed of the generator and thus, it is necessary, in a conventional case, to provide a mechanical gearbox between the rotor and the generator. By this, the rotation speed of the rotor is increased to the rated speed of the generator by the gearbox and then inputted to the generator.
In recent years, the gear box tends to become heavier and more expensive as the power generating apparatuses of the renewable energy type are getting larger to improve power generation efficiency. Thus, a power generating apparatus of a renewable energy type equipped with a hydraulic transmission adopting a combination of a hydraulic pump and a hydraulic motor is getting much attention. Normally, the hydraulic transmission includes a hydraulic pump driven by a rotation of a rotor, a hydraulic motor connected to a generator and a pressurized oil piping in which pressurized oil circulates.
For instance, Patent Document 1 describes a wind turbine generator which transmits rotation energy of a rotor driven by a wind power to a generator via a hydraulic transmission. In the wind turbine generator, to design a nacelle lighter, the hydraulic motor and the generator are arranged at a bottom of the tower (See FIG. 10 of Patent Document 1). In a similar manner, a wind turbine generator described in Patent Document 2 includes a hydraulic motor and a generator that are arranged at a bottom of a tower.
Patent Document 3 proposes a wind turbine generator in which all of the hydraulic pump, the hydraulic motor and the generator are arranged in the nacelle (See FIG. 7 of Patent Document 3). In the wind turbine generator, a supply piping and a return piping which are connected to the hydraulic pump are connected to the hydraulic motor.
Although not for the power generating apparatus of renewable energy type provided with the hydraulic transmission, a support for a wind turbine generator provided with a mechanical gearbox to support the mechanical gearbox by a nacelle via the support, is disclosed in Patent Literatures 4 and 5.
The hydraulic pump of the power generating apparatus of renewable energy type, in some cases, is attached to the rotating shaft rotating with the blade. In such case, the hydraulic pump is configured with a rotary part which rotates with the rotating shaft, a pump housing remaining still when the rotating shaft rotates, and a pump bearing provided between the rotary part and the pump housing to allow a relative rotation between them. For the standpoint of preventing the pump housing from rotating with the rotating shaft, it is necessary to support the pump housing by the nacelle in such a manner that the pump housing can firmly receive the torque transmitted from the rotating shaft via the rotary part.
However, by fixing the pump housing to the nacelle in a rigid manner to receive the torque, the following issues arise.
Specifically, the rotating shaft of the renewable energy power generating apparatus is subjected to heavy load from energy flow of the renewable energy, thereby causing the rotating shaft to bend. The energy flow is wind load in the case of a wind turbine generator. However, if the pump housing is fixed to the nacelle rigidly, the rotating shaft is constrained by the pump housing and the nacelle, causing the load from the bending of the rotating shaft to be concentrated on the main shaft bearing and the pump bearing of the hydraulic pump which supports the rotating shaft.
Particularly, attempts to increase the size of the rotor have been made in recent years to improve power generation efficiency. Accordingly, the load from the energy flow of the renewable energy increases and it becomes increasingly important to reduce the load concentration on the main shaft bearing and the pump bearing.
However, in Patent Documents 1 to 3, a specific structure for supporting the hydraulic pump by the nacelle is not disclosed and no solution for the issue of the load concentration caused by the bending of the rotating shaft is proposed.
In view of the above issue, the inventors were inspired to make a pump support structure of supporting the hydraulic pump by the nacelle such as to allow displacement of the hydraulic pump in a direction orthogonal to the axis of the rotating shaft (hereinafter, called as the orthogonal direction) while positively receiving the torque acting on the hydraulic pump from the rotating shaft. In such pump support structure, the displacement of the hydraulic pump in the vertical direction is allowed and thus, the rotating shaft is basically not constrained by the hydraulic pump, hence significantly reducing the concentrated load caused by the bending of the rotating shaft. This type of support structure is similar to the support via which the mechanical gearbox is supported by the nacelle as disclosed in Patent Literatures 4 and 5.
However, in the pump support structure, only the vertical displacement of the hydraulic pump is allowed and a relative displacement between the hydraulic pump and the hydraulic motor still occurs. This generates significant load on pressurized-oil pipings connecting the hydraulic pump and the hydraulic motor.
In view of the above issues, it is an object of the present invention to provide a power generating apparatus of renewable energy type which is capable of reducing the concentrated load on the main shaft bearing and the pump housing from the bending of the rotating shaft and the load on the pressurized-oil piping caused by the relative displacement between the hydraulic pump and the hydraulic motor.
An aspect of the present invention is a power generating apparatus of a renewable energy type which generates power from a renewable energy. The power generating apparatus may include, but is not limited to
a hub on which a rotor blade is mounted and which is rotated by the renewable energy received via the rotor blade;
a rotating shaft which is connected to the hub;
a hydraulic pump which is mounted on the rotating shaft and which is driven by rotation of the rotating shaft;
a hydraulic motor which is driven by pressurized oil from the hydraulic pump;
a generator which is coupled to the hydraulic motor;
a support which provides a reaction torque to the hydraulic pump from the rotating shaft while allowing a displacement of the hydraulic pump in a direction perpendicular to an axis of the rotating shaft, the hydraulic pump being supported by a nacelle through the support; and
a pressurized-oil piping which is at least partially constituted of a flexible tube and which connects an outlet port of the hydraulic pump to an inlet port of the hydraulic motor to supply the pressurized oil from the hydraulic pump to the hydraulic motor.
The flexible tube is a tube having flexibility and can be flexed freely to some extent. The material of the flexible tube is not limited as long as being able to withstand an expected pressure of the pressurized oil during the operation of the power generating apparatus of renewable energy type (e.g. 350 kgf/cm2). For instance, the flexible tube may be a tube which is made from various types of metal or resin such as PTFE, POM, PA, PVDF, FEP and PUR and which is reinforced with a steel wire such as a stainless wire.
In the above power generating apparatus of the renewable energy type, the support is provided so that the hydraulic pump is supported by the nacelle via the support. The support provides a reaction torque to the hydraulic pump from the rotating shaft while allowing a displacement of the hydraulic pump in a direction perpendicular to an axis of the rotating shaft. Therefore, it is possible to reduce the concentrated load on the main shaft bearing and the pump bearing caused by the bending of the rotating shaft while preventing the stationary part of the hydraulic pump (the pump housing) from rotating with the rotating shaft.
On the other hand, by allowing the vertical displacement of the hydraulic pump, the relative displacement between the hydraulic pump and the hydraulic motor which is not directly connected to the rotating shaft still Occurs. By making the entire pressurized-oil pipings connecting the hydraulic pump and the hydraulic motor as a rigid piping structure, significant load is generated on pressurized-oil pipings connecting the hydraulic pump and the hydraulic motor. The rigid piping structure is a piping structure which is configured by piping with high rigidity.
Therefore, in the above power generating apparatus of renewable energy type, the pressurized-oil piping is at least partially constituted of a flexible tube. By this, the relative displacement between the hydraulic pump and the hydraulic motor is absorbed by deformation of the flexible tube to reduce the load on the piping. As the temperature of the pressurized oil in the pressurized-oil line is high, heat stress is generated due to thermal expansion of the pressurized-oil piping. However, by forming the pressurized-oil piping at least partially by the flexible tube, it is possible to effectively absorb the thermal expansion of the pressurized-oil piping by the deformation of the flexible tube, suppressing the generation of the heat stress.
In the above power generating apparatus of the renewable energy type, the outlet port of the hydraulic pump may be arranged across a plane from the inlet port of the hydraulic motor, the plane being orthogonal to a line extending from the inlet port of the hydraulic motor to central axis of the hydraulic pump and along the central axis, and the pressurized-oil piping passes through the plane to extend from the inlet port to the outlet port.
Normally, the flexible tube has characteristics such as a minimum bending radius which is prescribed in accordance with the material, the size and so on. It is known that the use of the flexible tube at the bending radius below the minimum-bending radius shortens the life of the flexible tube. Herein, the greater the distance between the outlet port of the hydraulic pump and the inlet port of the hydraulic motor, the longer the flexible tube can be. Thus, the bending radius of the flexible tube is not much affected by the absorption of the relative displacement between the hydraulic pump and the hydraulic motor. For instance, in comparison of one flexible tube having a length of L1 and another flexible tube having a length of L2 (<L1), after absorbing the relative displacement, a change of the bending radius is smaller in the one flexible tube with the length L1 than the other flexible tube with the length L2. Therefore, to use the flexible tube at the bending radius not less than the minimum bending radius, it is preferable to arrange the outlet port of the hydraulic pump and the inlet port of the hydraulic motor as far away from each other as possible to suppress the change of the bending radius of the flexible tube caused by the absorption of the relative displacement between the hydraulic pump and the hydraulic motor.
However, with space restriction inside the nacelle, the hydraulic motor may be inevitably arranged near the hydraulic pump. In such case, the distance between the outlet port of the hydraulic pump and the inlet port of the hydraulic motor can be increased only to a certain extent.
In this aspect, by arranging the outlet port of the hydraulic pump across the plane from the inlet port of the hydraulic motor (the plane is orthogonal to the line extending from the inlet port to the central axis of the hydraulic pump and along the central axis), even in the case where the hydraulic motor is inevitably arranged near the hydraulic pump due to the space restriction in the nacelle, it is possible to secure enough length of the pressurized-oil piping connecting the outlet port and the inlet port. As a result, it is possible to increase the length of the flexible tube so as to suppress the change of the bending radius of the flexible tube caused by the absorption of the relative displacement between the hydraulic pump and the hydraulic motor, and to use the flexible tub at the bending radius not less than the minimum bending radius.
In the above power generating apparatus of the renewable energy type, the hydraulic pump may be mounted on an end of the rotating shaft which is farther from the hub, the hydraulic pump may include an endplate which constitutes an end face of the hydraulic pump located on a side facing towards the hub, the endplate having an arm part which projects radially outward from the hydraulic pump, and the arm part of the hydraulic pump may be supported by the nacelle via the support.
By mounting the hydraulic pump on the end of the rotating shaft which is farther from the hub, it is easy to perform the maintenance of the hydraulic pump from a rear side of the hydraulic pump. A front side is used to describe a side facing toward the hub and the rear side is used to describe a side that is farther from the hub in the axial direction of the rotating shaft. Further, by providing the endplate having the arm part and supported by the nacelle via the support towards the hub (on the front side), the support structure of the endplate including the arm part and the support does not get in the way when performing the maintenance on the hydraulic pump from the rear side of the hydraulic pump.
In such case, the outlet port may be provided in the endplate which constitutes the end face of the hydraulic pump located on the side facing towards the hub.
By this, it is possible to arrange the pressurized-oil piping connecting the outlet port of the hydraulic pump to the inlet port of the hydraulic motor in a space on the front side within the nacelle, thereby further improving the ease of performing the maintenance from the rear side of the hydraulic pump.
In the above power generating apparatus of the renewable energy type, the hydraulic motor is arranged lateral relative to an axis of the hydraulic pump, and the generator may be located between the hub and the hydraulic motor.
By this, the hydraulic motor and the generator are not arranged on the rear side of the hydraulic pump, leaving enough maintenance space on the rear side of the hydraulic pump. As a result, it is possible to further improve the ease of performing the maintenance.
The generator which is normally larger in size than the hydraulic motor is arranged between the hub and the hydraulic motor (i.e. on the front side of the hydraulic motor). Thus, when the crane lifts the hydraulic motor, the crane does not move over the generator. As a result, the ease of performing the maintenance is further enhanced.
In the above power generating apparatus of the renewable energy type, the pressurized-oil piping may include, but is not limited to, the flexible tube, a first rigid coupling which connects a first end of the flexible tube to the outlet port of the hydraulic pump, a second rigid coupling which connects a second end of the flexible tube to the inlet port of the hydraulic motor, and an accumulator may be connected to the second rigid coupling.
Due to the action of the flexible tube, the second rigid coupling which connects the pressurized-oil piping partially formed by the flexible tube and the inlet port of the hydraulic motor is hardly affected by the vertical displacement of the hydraulic pump. Thus, by connecting the accumulator to the second rigid coupling, even when there is displacement between the hydraulic pump and the accumulator, the accumulator can be supported to the nacelle side in a stable manner by a simple structure.
The above power generating apparatus of the renewable energy type may further include a base plate which is supported by the nacelle via at least one of an elastic member and a damper mechanism and on which the hydraulic motor and the generator are mounted.
In the above power generating apparatus of the renewable energy type, the hydraulic motor and the generator are rotating machines and respectively vibrate as well. Thus, by mounting the hydraulic motor and the generator on the base plate supported by the nacelle via at least one of the elastic member and the damper mechanism, it is possible to damp the vibration of the hydraulic motor and the generator and it is also possible to firmly support the hydraulic motor and the generator by the nacelle.
Another aspect of the present invention is a power generating apparatus of a renewable energy type which generates power from a renewable energy and which may include, but is not limited to:
a hub on which at least one blade is mounted and which is rotated by the renewable energy received via the rotor blade;
a rotating shaft which is connected to the hub;
a hydraulic pump which is mounted on the rotating shaft and which is driven by rotation of the rotating shaft;
a hydraulic motor which is driven by pressurized oil from the hydraulic pump; and
a generator which is coupled to the hydraulic motor. The hydraulic pump may include an endplate having an arm part which projects radially outward from the hydraulic pump, the endplate may be formed with an interior channel through which the pressurized oil flows to the arm part, and the hydraulic motor may be fixed to the arm part and fluidly communicates with the hydraulic pump via the interior channel.
In the above power generating apparatus of the renewable energy type, the hydraulic motor is fixed to the arm part which constitutes a part of the end plate of the hydraulic pump and thus, there is almost no relative displacement between the hydraulic pump and the hydraulic motor. It is now possible to eliminate the load caused by the relative displacement between the hydraulic pump and the hydraulic motor.
Further, the endplate having the arm part projecting outward in the radial direction constitutes the end face of the hydraulic pump. The hydraulic motor attached to the arm part is fluidly connected with the hydraulic pump via the internal flow path formed inside the end plate having the arm part and thus, it is not necessary to provide a piping between the hydraulic pump and the hydraulic motor. Therefore, it is possible to avoid issues which arise in the case of providing a piping between the hydraulic pump and the hydraulic motor, such as thermal expansion of the piping and leaking of the oil from the connection part between the pipings.
The above power generating apparatus of the renewable energy type may further include a support which provides a reaction torque to the hydraulic pump from the rotating shaft while allowing a displacement of the hydraulic pump in a direction perpendicular to an axis of the rotating shaft, the arm part of the hydraulic pump being supported by a nacelle through the support.
The support is provided so that the arm part of the hydraulic pump is supported by the nacelle through the support. By this, the torque loaded on the hydraulic pump from the rotating shaft can be received by the support while allowing the displacement of the hydraulic pump in the orthogonal direction. Thus, a stationary part of the hydraulic pump (the pump housing) is prevented from rotating with the rotating shaft and the concentrated load on the main shaft bearings and the pump bearing due to the bending of the rotating shaft can be reduced.
In such case, the hydraulic pump may be fixed to an end of the rotating shaft which is farther from the hub, and the endplate may constitute an end face of the hydraulic pump located on a side facing towards the hub.
In this manner, by fixing the hydraulic pump to the rear end of the rotating shaft, operator's access to the hydraulic pump from the rear side of the hydraulic pump is improved and thus, it is easy to perform the maintenance of the hydraulic pump. Further, by providing the endplate having the arm part and supported by the nacelle via the support towards the hub (on the front side), the support structure of the endplate including the arm part and the support does not get in the way when performing the maintenance on the hydraulic pump from the rear side of the hydraulic pump.
Further, in the above case, the power generating apparatus may further include a main shaft bearing through which the rotating shaft is rotatably supported by the nacelle, and the hydraulic pump may be fastened to a bearing housing of the main shaft bearing via a vibration insulating bush.
In this manner, by fastening the hydraulic pump to the bearing housing of the main shaft, the hydraulic pump can be supported firmly while damping change of position of the hydraulic pump by the vibration insulating bushes.
Furthermore, in the above case, the hydraulic motor may include a pair of motor modules that have the same structure, and the pair of the motor modules may have output shafts that are coupled to each other inside the arm part.
By this, the motor modules are supported on the front and rear faces of the arm part and thus a shaft length from the support point becomes shorter. Thus, the vibration of the hydraulic motor can be suppressed.
Meanwhile, each of the pair of the motor modules may include a plurality of sets of: a cylinder; a piston sliding inside the cylinder by the pressurized oil; an eccentric cam rotated by the piston, the plurality of sets being arranged in an axial direction of the hydraulic motor, and the eccentric cams of the sets may be different from each other in phase.
In this manner, the eccentric cams of the plurality of the sets arranged in the axial direction of the hydraulic motor are arranged different from each other in phase. As a result, vibrations from the motor modules are balanced, thereby suppressing the vibrations.
Further in the above case, an accumulator may be fixed to the endplate, said accumulator being fluidly connected to the interior channel.
In this manner, the accumulator connected fluidly to the interior channel is fixed to the front endplate. Thus, there is almost no displacement between the interior channel formed in the front endplate and the accumulator, making it hard for the pressurized oil to leak.
Furthermore, the power generating apparatus of the renewable energy type may be a wind turbine generator which generates power from wind as a form of the renewable energy.
In the one aspect of the present invention, the support is provided so that the hydraulic pump is supported by the nacelle via the support and the support provides a reaction torque to the hydraulic pump from the rotating shaft while allowing a displacement of the hydraulic pump in the orthogonal direction. Therefore, it is possible to reduce the concentrated load on the main shaft bearing and the pump bearing caused by the bending of the rotating shaft while preventing the stationary part of the hydraulic pump (the pump housing) from rotating with the rotating shaft. Further, the pressurized-oil piping is at least partially constituted of a flexible tube and thus, the relative displacement between the hydraulic pump and the hydraulic motor is absorbed by deformation of the flexible tube to reduce the load on the piping. Furthermore, the pressurized-oil piping is at least partially formed by the flexible tube and thus, it is possible to effectively absorb the thermal expansion of the pressurized-oil piping by the deformation of the flexible tube, suppressing the generation of the heat stress.
In said another of the present invention, the hydraulic motor is fixed to the arm part which constitutes a part of the end plate of the hydraulic pump and thus, there is almost no relative displacement between the hydraulic pump and the hydraulic motor. It is now possible to eliminate the load caused by the relative displacement between the hydraulic pump and the hydraulic motor. Further, the endplate having the arm part projecting outward in the radial direction constitutes the end face of the hydraulic pump. The hydraulic motor attached to the arm part is fluidly connected with the hydraulic pump via the internal flow path formed inside the end plate and thus, it is no longer necessary to provide a piping between the hydraulic pump and the hydraulic motor. Therefore, it is possible to avoid issues which arise in the case of providing a piping between the hydraulic pump and the hydraulic motor, such as thermal expansion of the piping and leaking of the oil from the connection part between the pipings.
Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It is intended, however, that unless particularly specified, dimensions, materials, shape, its relative positions and the like shall be interpreted as illustrative only and not limitative of the scope of the present.
In reference to
In the embodiment, the wind turbine generator 1 of a propeller type is described as an example. However, the present invention is not limited to this example and can be applied to various types of wind turbine generators.
As illustrated in
The rotor 2 is constructed such that a rotating shaft 6 is connected to a hub 3 having blades 4. For instance, three blades 4 extend radially from the hub 3 and each of the blades 4 is mounted to the hub 3 connected to the rotating shaft 6. By this, the wind power acting on the blades 4 turns the entire rotor 2, the rotation of the rotor 2 is inputted to the hydraulic transmission 5 via the rotating shaft 6.
The hydraulic transmission 5 is arranged in the nacelle 8. The hydraulic transmission 5 includes a hydraulic pump 20 of a variable displacement type which is rotated by the rotating shaft 6, a hydraulic motor 30 of a variable displacement type which is connected to the generator 35, and a pressurized-oil pipings which connecting the hydraulic pump 20 and the hydraulic motor 30 fluidly. The pressurized-oil line includes a high-pressure oil line 40 and a low-pressure oil line 50. By this, the rotation of the rotating shaft 6 rotates the hydraulic pump 20, thereby creating a pressure difference between a high-pressure oil flowing in the high-pressure oil line 40 and a low-pressure oil line flowing in the low pressure oil line 50. The pressure difference drives the hydraulic motor 30.
The generator 35 is connected to an output shaft 34 of the hydraulic motor 30 and generates power by torque from the hydraulic motor 30.
In reference to
As shown in
As shown in
The hydraulic pump 20 is driven by the rotation of the rotating shaft 6. In the hydraulic pump 20, a pump housing 19 is formed by a cylindrical member 23, a front endplate 21 provided on the front side of the cylindrical member 23 and a rear endplate 22 provided on the rear side of the cylindrical member 23. In the pump housing 19, a pump module 25 is provided.
The pump module 25 is configured with a cylinder 26, a piston 27 and a cam 28. The cam 28 is formed into a circular shape and is fixed to an outer periphery of a cylindrical member 29. The cylindrical member 29 is connected to a rear end of the rotating shaft 6 via a shrink-disk coupling structure 15. By this, the rotation of the rotating shaft 6 is transmitted to the cylindrical member 29 via the shrink-disk coupling structure 15 to rotate the cam 28. The rotating shaft 6 and the cylindrical member 29 are connected by the shrink-disk coupling structure 15 or other coupling structures such as a flange coupling, a key coupling and an involute spline coupling.
In this manner, by fixing the hydraulic pump 20 to the rear end of the rotating shaft 6, operator's access to the hydraulic pump 20 from the rear side of the hydraulic pump 20 is improved and thus, it is easy to perform the maintenance of the hydraulic pump 20. Specifically, the space on the rear side of the hydraulic pump 20 in the nacelle can be used for performing the maintenance. During the maintenance, as shown in
During the operation of the wind turbine generator, the crane 18 is folded. When performing maintenance of the wind turbine generator 1, the crane 18 is extended or contracted to an operation position and is used for moving or disassembling devices such as the hydraulic pump 20 and the hydraulic motor 30. In this process, the rotating shaft 6 projecting from the rear side of the hydraulic pump 20 interferes with the operation. In the above structure with the hydraulic pump 20 fixed to the rear end of the rotating shaft 6, it is possible to leave a space on the rear side of the hydraulic pump 20, thereby improving ease of performing the maintenance.
The support 7 is configured to receive the torque applied to the hydraulic pump 20 from the rotating shaft 6 while allowing a displacement of the hydraulic pump 20 (specifically, the pump housing 19) in a direction orthogonal to the axis of the rotating shaft 6 (hereinafter called the orthogonal direction).
The hydraulic pump 20 is configured such that a rotating part (the cylindrical member 29 and the cam 28) rotating with the rotating shaft 6 and the pump housing 19 remaining still when the rotating shaft 6 rotates, can rotate relatively by means of the pump bearing 17. This generates a relative rotation of the cam 28 with respect to the piston 27 supported by the pump housing 19, thereby raising the pressure of the operating oil in the hydraulic pump 20. To make the hydraulic pump 20 normally, it is necessary to firmly receive the torque transmitted to the pump housing 19 from the rotating shaft 6 via the rotating part of the hydraulic pump 20. Therefore, in the embodiment, the support 7 is provided to receive torque on the pump housing 19 from the rotating shaft 6.
The rotating shaft 6 of the wind turbine generator 1 being subjected to the wind load inputted from the blade 4, is acting to bend. If the pump housing 19 is fixed to the nacelle 8 rigidly, the rotating shaft 6 is bounded by the pump housing 19 and the nacelle 8, causing the load caused by the bending of the rotating shaft to be concentrate on the first main shaft bearing 11, the second main shaft bearing 12 and the pump bearing 17. Therefore, the support 7 supports the pump housing 19 to allow a displacement of the hydraulic pump 20 in a direction orthogonal to the axis of the rotating shaft 6 (hereinafter called as the orthogonal direction). By this, it is possible to reduce the concentrated load acting on the main shaft bearings 11 and 12 and the pump bearing 17 due to the bending of the rotating shaft 6.
In reference to
As shown in
Each of the oil chambers 71 to 74 changes volume depending on a position of the first or second arm part 21b1 and 21b2 in the vertical direction.
As shown in
As shown in
By making each of the oil chambers 71 to 74 from an elastic member such as rubber, each of the oil chambers 71 to 74 may be configured with a variable volume. In such case, by a principle described in reference to
An outlet port 24a of the hydraulic pump 20 is preferably arranged in the front endplate 21 constituting an end face of the hydraulic pump 20 located on a side facing towards the hub 3. By this, it is possible to arrange the high pressure oil line 40 connecting the outlet port 24a of the hydraulic pump to an inlet port 31 of the hydraulic motor 30 in a space on the front side within the nacelle 8, thereby further improving the ease of performing the maintenance from the rear side of the hydraulic pump 20.
So far explained is the case where the arm parts 21 (21b1, 21b2) and the outlet port 24a are formed in the front endplate 21. However, this is not limitative and the arm parts 21 (21b1, 21b2) and the outlet port 24a may be formed in the rear endplate 22.
In reference to
The generator 35 which is normally larger in size than the hydraulic motor 30 is arranged between the hub 3 and the hydraulic motor 30 (i.e. on the front side of the hydraulic motor 30). Thus, when the crane 18 lifts the hydraulic motor 30, the crane does not move over the generator 35. As a result, the ease of performing the maintenance is further enhanced.
The hydraulic motor 30 and the generator 35 are preferably mounted on a base plate 84. The base plate 84 is supported by the frame 81 via at least one of an elastic member and a damper.
In the wind turbine generator 1, the hydraulic motor 30 and the generator 35 which are rotating machines, respectively vibrate as well. Thus, by mounting the hydraulic motor 30 and the generator 35 on the base plate 84 supported by the nacelle 8 via at least one of the elastic member and the damper mechanism, it is possible to damp the vibration of the hydraulic motor 30 and the generator 35 and it is also possible to firmly support the hydraulic motor 30 and the generator 35 by the nacelle 8.
In reference to
The high-pressure oil line 40 is at least partially constituted of a flexible tube 43. Specifically, in the high-pressure oil line 40, a connection base to the outlet port 24a of the hydraulic port 24a and a connection base to the inlet port 31 of the hydraulic motor 30 may be made of a rigid coupling 41, 42 and between the rigid couplings 41 and 42, the flexible tube 43 may be provided. Meanwhile, the flexible tube 43 may be at least partially flexed between the rigid couplings 41 and 42. By this, it is possible to effectively absorb the relative displacement between the hydraulic pump 20 and the hydraulic motor 30, the vibration of the hydraulic pump 20 or the hydraulic motor 30, or the thermal expansion of the piping by means of the flexible tube 43. The flexible tube 43 may be arranged such as to bypass the rotating shaft 6.
The flexible tube 43 is a tube having flexibility and can be flexed freely to some extent. The flexible tube 43 is often called by other names such as a flexible pipe and a flexible hose. Specifically, the flexible tube may be any tube that can withstand an expected pressure of the pressurized oil during the operation of the power generating apparatus of renewable energy type (e.g. 350 kgf/cm2). For instance, the flexible tube may be a tube which is made from various types of metal or resin such as PTFE, POM, PA, PVDF, FEP and PUR and which is reinforced with a steel wire such as a stainless wire.
As shown in
Normally, the flexible tube 43 has characteristics such as a minimum bending radius which is prescribed in accordance with the material, the size and so on. It is known that the use of the flexible tube at the bending radius below the minimum bending radius shortens the life of the flexible tube.
The greater the distance between the outlet port 24a of the hydraulic pump 20 and the inlet port 31 of the hydraulic motor 30, the longer the flexible tube 43 can be. Thus, the bending radius of the flexible tube 43 is not much affected by the absorption of the relative displacement between the hydraulic pump and the hydraulic motor 30. For instance, as shown in
However, with space restriction in the nacelle 8, the hydraulic motor 30 may be inevitably arranged near the hydraulic pump 20. In such case, the distance between the outlet port 24a of the hydraulic pump 20 and the inlet port 31 of the hydraulic motor 30 can be increased only to a certain extent.
Thus, by arranging the outlet port 24a of the hydraulic pump 20 and the inlet port 31 of the hydraulic motor 30 to achieve the positional relationship as described above, even in the case where the hydraulic motor 30 is arranged near the hydraulic pump 20 due to the space restriction in the nacelle 8, it is possible to secure enough length of the high pressure oil line connecting the outlet port 24a and the inlet port 31. As a result, it is possible to increase the length of the flexible tube 43 so as to suppress the change of the bending radius of the flexible tube 43 caused by the absorption of the relative displacement between the hydraulic pump 20 and the hydraulic motor 30, and to use the flexible tub 43 at the bending radius not less than the minimum bending radius.
The above positional relationship between the outlet port 24a and the inlet port 31 is applied to the outlet port 24a and the inlet port 31 which are fluidly connected by the high pressure oil line 40. Thus, as shown in
In the case where more than one output port 24a of the hydraulic pump 20 is formed in the endplate 21, the outlet ports 24a may be arranged on both sides of an axis of the hydraulic pump 20 respectively and preferably arranged at different heights. By this, the connection bases of the outlet ports 24a of the high pressure oil line 40 do not interfere with one another.
As shown in
Due to the action of the flexible tube 43, the branch pipe which connects the high pressure oil line 40 partially formed by the flexible tube 40 and the inlet port 31 of the hydraulic motor 30 is hardly affected by the vertical displacement of the hydraulic pump 20. Thus, by connecting the accumulator 47 to the branch pipe 46, even when there is displacement between the hydraulic pump 20 and the accumulator 47, the accumulator 47 can be supported to the nacelle side in a stable manner by a simple structure.
As described above, in the present embodiment, the torque loaded on the hydraulic pump 20 from the rotating shaft 6 can be received by the support 7 supporting the hydraulic pump 20 to the nacelle 7 while allowing the displacement o the hydraulic pump 20 in the orthogonal direction. Thus, a stationary part of the hydraulic pump 20 (the pump housing 19) is prevented from rotating with the rotating shaft 6 and the concentrated load on the main shaft bearings 11 and 12 and the pump bearing 17 due to the bending of the rotating shaft 6 can be reduced. Further, the high pressure oil line 40 is at least partially formed by the flexible tube 43 and thus, the relative displacement between the hydraulic pump 20 and the hydraulic motor 30 can be absorbed by the deformation of the flexible tube 43, thereby easing the load on the high pressure oil line 40. Furthermore, the pressurized oil streaming in the high pressure oil line 40 has high temperature, causing the high pressure oil line to thermally expand. However, by forming the high pressure oil line 40 at least partially by the flexible tube 43, the thermal expansion of the high pressure oil line 40 can be absorbed by the deformation of the flexible tube, thereby preventing generation of thermal stress.
In the present embodiment, the high pressure oil line 40 may be at least partially formed by the flexible tube 43 and the low pressure oil line 50 connecting the outlet port 32 of the hydraulic motor 30 and the inlet port 28 of the hydraulic pump 20 to supply low pressure oil may be at least partially formed by the flexible tube 43.
The low pressure oil line 50 is connected to the outlet port 32 formed in a side part of the hydraulic motor 30 at one end and to the inlet port 24b formed at a bottom of the hydraulic pump 20 at other end. In the low pressure oil line 50 between the outlet port 32 and the inlet port 24b, an accumulator 54 for preventing the pulsation, a tank 55 for storing the pressurized oil, a cooler for cooling the pressurized oil and a filter (not shown) for removing foreign objects in the pressurized oil are arranged.
Specifically, in the low pressure oil line 50, preferably the connection base to the outlet port 32 of the hydraulic motor 30, the connection base to the inlet port 24b of the hydraulic pump 20 and the connection part of the devices connected to the low pressure oil line 50 are formed by rigid couplings 51 and between the rigid couplings is partially connected by the flexible tube 43. The structures of the flexible tube 43 and the rigid coupling 51 are approximately the same as those of the high pressure oil line 40. However, the low pressure oil line 50 has temperature and pressure conditions which are not as strict as those of the high pressure oil line 40. In order to lower the component cost, it is possible to use a tube with lower heat resistance and pressure resistance than the high pressure oil line 40.
In this manner, by forming the low pressure oil line 50 at least partially by the flexible tube 43, it is possible to effectively absorb the relative displacement between the hydraulic pump 20 and the hydraulic motor 30, the vibration of the hydraulic pump 20 or the hydraulic motor 30, or the thermal expansion of the piping 50 by means of the flexible tube 43.
Next, the wind turbine generator 1 in relation to a second embodiment is now explained. The wind turbine generator 1 of the second embodiment is substantially the same as the first embodiment described above except for a few points. Herein, the same reference numerals are given without adding explanations for those configurations that are the same as the first embodiment and mainly the few points that are different from the first embodiment are explained.
In reference to
As shown in
The bearing housings 10A and 10B are fixed to the frame 81 of the nacelle 8. The bearing housings 10A and 10B house the bearings 11 and 12 respectively. Further, the bearing housings 10A and 10B are connected to each other by the connection frame 10C (see
The front endplate 121 includes an annular part 121a constituting the end face of the hydraulic pump 120 and an arm part 121b projecting in the radial direction of the annular part 121a.
The arm part 121b is supported by the frame 81 via the support 7 in the same manner as the first embodiment. In this manner, the hydraulic pump 120 is supported by the nacelle 8.
The front endplate 121 may be a single-piece member with the annular part 121a and the part parts 121b formed integrally, or may be configured by forming the annular part 121a and the arm parts 121b separately and connecting the pieces by a fastening member.
The support 7 is configured to receive the torque applied to the hydraulic pump 120 from the rotating shaft 6 while allowing a displacement of the hydraulic pump 120 in the direction orthogonal to the axis of the rotating shaft 6. The detailed exemplary structure of the support 7 is the same as the one shown in
By supporting the arm part 121b by the support in the manner described above, a stationary part of the hydraulic pump 20 (the pump housing 19) is prevented from rotating with the rotating shaft 6 and the concentrated load on the main shaft bearings 11 and 12 and the pump bearing 17 due to the bending of the rotating shaft 6 can be reduced.
The interior channel 140 includes discharge flow paths 141 for drawing the high pressure oil from the pump module to the front endplate 121, a manifold 142 for connecting the discharge flow paths and a supply flow path 143 fir supply the high pressure oil from the manifold 142 to the hydraulic motor 130. The discharge flow path 141 and the manifold 142 are provided in the annular part 121a of the front endplate 121. The supply flow path 143 is provided in the arm part 141b. In the second embodiment, a structure similar to the first embodiment is applied to the low pressure oil line.
The hydraulic motor 30 is fixed to the arm part 121b. Specifically, the front endplate 121 is formed with a pair of arm parts 121b projecting from left and right sides of the annular part 121a and the hydraulic motors 130 is fixed to the end part of the arm parts 121b. The hydraulic pump 120 and the hydraulic motor 130 are fluidly connected by the interior channel 140.
To the front endplate 121, at least one accumulator 145 may be connected. The accumulator 145 is connected fluidly to the supply flow path 143 formed in the arm part 121b and supported by the arm part 121b of the hydraulic motor 120. The accumulator 145 is provided, for instance, to accumulate energy of the high pressure oil and to prevent the pulsation.
In this manner, the accumulator 145 connected fluidly to the interior channel 140 is fixed to the front endplate 121. Thus, there is almost no displacement between the interior channel formed in the front endplate 121 and the accumulator 145, making it hard for the pressurized oil to leak.
The supply flow path 143 formed in the arm part 121b branches into a pair of branched paths midway. The pair of branched paths are connected to oil flow paths 135A and 135B of the pair of the motor modules 130A and 130B respectively. Therefore, the high pressure operating oil discharged from the hydraulic pump 120 flows through the supply flow path 143 of the arm part 121b and enters the oil flow paths 135A and 135B of the pair of the motor modules 130A and 130B. The pair of the motor modules 130A and 130B are fixed to the arm part 121v at an end face. Meanwhile, a rubber sheet 151 is preferably provided between the end face of the each of the motor modules 130A and 130B and a fixing surface of the arm part 121b. The rubber sheet 151 is provided to prevent the operating oil from leaking outside even when the operating oil leaks from the oil flow path 135a and 135B, and to absorb the vibration of the motor modules 130A and 130B so that the vibration is not transmitted to the hydraulic pump 120. In such case, it is also preferable to provide a rubber sheet outside a flange which connects the motor module 130A, 130B to the arm part 121b.
As a detailed exemplary structure, the supply flow path 143 and the oil flow path 135A, 135B of the motor module 130A, 130B may be connected by a cylindrical tube seal 152. In such case, an annular rubber sheet 153 is preferably provided between an end of the tube seal 152 and an end of the oil flow path 135A, 135B so as to prevent the pressurized oil from leaking from the connection part. In a clearance on an outer periphery of the tube seal 152, a spring 154 is arranged in close contact with the outer periphery of the tub seal 152 in an elastically-deformed state. This prevents leaking of the pressurized oil from the clearance. Further, the rubber sheets 151 and 153 and the tube seal 152 are constituted of a material which is not limited as long as it has elasticity.
In reference to
Each of the motor modules 130A and 130B is provided with a cylinder block 11 which is formed into a continuous loop around an eccentric cam 138. The cylinder block 131 includes at least one cylinder 136. Each cylinder 136 is provided with the eccentric cam 138 and a set of a piston 137, a high pressure valve and a low pressure valve (the valves are not shown). In this embodiment, the cylinder block of a continuous loop is used. However, this is not limitative and it is possible to use a cylinder block which is separable in the circumferential direction.
The cylinder 136 is provided in the cylinder block 131 and inside the cylinder 136, a hydraulic chamber is formed between the cylinder 136 and the piston 137.
From a standpoint of smoothly converting a motion of the piston 137 moving upward and downward into a rotary motion of the eccentric cam 138, the piston 137 is formed by a piston body 137a and a piston roller or a piston shoe 137b. The piston body 137a slides inside the cylinder 136 and the piston roller or the piston shoe 137b is fixed to the piston body 137a and engages with a curved surface of the eccentric cam 138. Herein, the piston roller is a member which rotates in contact with the curved surface of the eccentric cam 138 and the piston shoe is a member which slides in contact with the curved surface of the eccentric cam 138.
The eccentric cam 138 is a cam which is provided eccentrically with respect to an axial center of the output shaft 134 connected to the generator 135. While the piston 137 completes one up-and-down motion, the eccentric cam 138 and the output shaft 134 to which the eccentric cam 138 complete one rotation.
A plurality of sets of the piston 137, the cylinder 137 and the eccentric cam 138 are arranged in the axial direction of the output shaft 134. Further, The eccentric cams 138 of the plurality of sets are arranged different from each other in phase.
In the motor module 130A, 130B having the above structure, the piston 137 is moved upward and downward by a pressure difference between the high pressure oil line and the low pressure oil line. In a motor stroke of the piston 137 starting from a top dead center and reaching a bottom dead center, the high pressure valve is opened and the low pressure valve is closed and thus, the high pressure oil is supplied to the hydraulic chamber. Then, in a discharge stroke of the piston 137 starting from the bottom dead center and reaching the top dead center, the high pressure valve is closed and the low pressure valve is opened and thus, the pressurized oil within the hydraulic chamber is discharged. In this manner, the high pressure oil introduced to the hydraulic chamber pushes the piston 135 downward to the bottom dead center in the motor stroke, thereby rotating the output shaft 134 with the eccentric cam 138.
In the hydraulic motor 130, the eccentric cams 138 of the plurality of the sets arranged in the axial direction of the hydraulic motor 30 are arranged different from each other in phase. As a result, vibrations from the motor modules 130A and 130B are balanced, thereby suppressing the vibrations.
As described above, in the present embodiment, the hydraulic motor 130 is fixed to the arm part 121b which constitutes a part of the end plate 121 of the hydraulic pump 120 and thus, there is almost no load due to the relative displacement between the hydraulic pump 120 and the hydraulic motor 130. It is now possible to prevent the load caused by the relative displacement between the hydraulic pump 120 and the hydraulic motor 130 from being applied to the piping between the hydraulic pump 120 and the hydraulic motor 130. In the second embodiment, there is no component that is considered as the piping between the hydraulic pump 120 and the hydraulic motor 130.
Further, the endplate 121 having the arm part 121b projecting outward in the radial direction constitutes the end face of the hydraulic pump 120. The hydraulic motor 130 attached to the arm part 121b is fluidly connected with the hydraulic pump 120 via the interior channel 140 formed inside the end plate 121 having the arm part 121b and thus, it is not necessary to provide a piping between the hydraulic pump 120 and the hydraulic motor 130, in which the high pressure oil flows. Therefore, it is possible to avoid issues which arise in the case of providing a piping between the hydraulic pump 120 and the hydraulic motor 130, such as thermal expansion of the piping and leaking of the oil from the connection part between the pipings.
By fixing the hydraulic pump 120 to the rear end of the rotating shaft 6, operator's access to the hydraulic pump 120 from the rear side of the hydraulic pump 120 is improved and thus, it is easy to perform the maintenance of the hydraulic pump 120. Further, by providing the endplate 121 having the arm part 121b and supported by the nacelle 8 via the support 7 towards the hub 3 (on the front side), a support structure of the endplate 121 including the arm part 121 and the support 7 does not get in the way when a worker performs a maintenance on the hydraulic pump 120 from the rear side of the hydraulic pump 120.
In the above embodiment, the hydraulic pump 120 is supported by the nacelle 8 by connecting the arm part 121b of the hydraulic pump 120 to the frame 81 via the support 7. However, this is not limitative and the hydraulic pump 120 may be supported by the nacelle 8 by fastening the hydraulic pump 120 to the bearing housing 10B on the rear side as shown in
In a hydraulic transmission 100′ shown in
While the present invention has been described with reference to exemplary embodiments, it is obvious to those skilled in the art that the first embodiment and the second embodiment may be freely combined and various changes may be made without departing from the scope of the invention.
For example, in the above embodiment, the hydraulic pump is connected to one end of the rotating shaft 6, which is on the rear side. However, this is not limitative and the rotating shaft 6 may be arranged through the hydraulic pump. In such case, the bearings are arranged on the front side and the rear side of the hydraulic pump 20, 120, 120′.
| Number | Date | Country | Kind |
|---|---|---|---|
| PCT/JP2010/006977 | Nov 2010 | JP | national |
| PCT/JP2010/006981 | Nov 2010 | JP | national |
| PCT/JP2011/058647 | Apr 2011 | JP | national |
| PCT/JP2011/071674 | Sep 2011 | JP | national |
| PCT/JP2011/071676 | Sep 2011 | JP | national |
| PCT/JP2011/071677 | Sep 2011 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP11/06695 | 11/30/2011 | WO | 00 | 5/2/2012 |
