JP2006177268A - Rotatably supporting device for wind power generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure capable of preventing a scope of wind velocity for generating electric power by a wind power generator from becoming narrow and ensuring the life of durability of tapered roller bearings 2, 2 for supporting a main shaft 1 connected with and fixed on a rotor. <P>SOLUTION: Pre-load load to be given to each tapered roller bearing 2, 2 is freely adjusted by a hydraulic cylinder 10. When wind velocity around the wind power generator is less than cut-in wind velocity, pre-load load is set to zero. Consequently, start torque of each tapered roller bearing 2, 2 is reduced to improve start property of the rotor. When the wind velocity is above cut-in wind velocity, pre-load load is increased in accordance with the wind velocity to ensure rigidity required in each tapered roller bearing 2, 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  A rotation support device for a wind turbine generator according to the present invention includes a main shaft coupled and fixed to a rotation center portion of a rotor (a rotating body with blades such as blades) constituting the wind power generator, or between the main shaft and a generator. The rotating shaft that constitutes the transmission provided in the above is utilized for rotatably supporting the housing with a rolling bearing.

  In recent years, wind power generation, which is a power generation method using natural energy, has been attracting attention for the purpose of improving the global environment by reducing carbon dioxide. The wind turbine generator rotates a rotor by using kinetic energy of wind and rotationally drives a generator by a main shaft whose end is coupled and fixed to the rotation center of the rotor. Conventionally, for example, those described in Patent Documents 1 to 3 are known as such wind power generators. In any wind power generator, in order to ensure power generation efficiency, a transmission is provided between the main shaft and the power generator, and the power generator is rotationally driven with the rotational speed of the main shaft increased. It is configured like this.

  Further, a wind turbine generator of a horizontal axis type (a type in which the main shaft is disposed horizontally) is often used, and is generally used with the rotor facing upwind. In general, such a wind turbine generator has a surrounding wind speed (speed of the wind toward the rotor) equal to or higher than a predetermined lower limit wind speed called a cut-in wind speed and a predetermined upper limit wind speed called a cut-out wind speed. The generator is configured to rotate only in the following cases. That is, in order to obtain stable power, when the surrounding wind speed is lower than the cut-in wind speed, the main shaft and the generator are disconnected by a clutch device or the like so that the generator is not driven to rotate. In order to prevent the main shaft from over-rotating and failure of the device, when the surrounding wind speed exceeds the cut-out wind speed, the blade posture is made less susceptible to wind force and the main shaft The rotation is stopped by a brake device so that the generator is not rotationally driven.

  In the case of such a wind power generator, the main shaft, whose end is coupled and fixed to the rotation center of the rotor, is supported in a cantilever manner on the housing by a rolling bearing. The rolling bearing supports the load applied to the rotor (weight, pressing force by wind, etc.). On the other hand, the load applied to the rotor varies in various ways as the surrounding wind conditions (wind speed, wind direction) change. Especially in the case of strong winds, the rotor part is not subject to blade vibration or blade load. Equilibrium may occur. Therefore, the rolling bearing is used under severe load conditions. On the other hand, since the wind turbine generator is installed at a high place on the top of the steel tower, it is difficult to perform maintenance work such as replacement of the rolling bearing, so that the rolling bearing has an early life under severe load conditions as described above. It is not preferable to reach this. Therefore, it is desirable to ensure a sufficient durable life of the rolling bearing so that the maintenance work does not have to be performed for a long time (at least 20 years, preferably longer).

  In general, the durability life of a rolling bearing can be improved by applying a preload to the rolling bearing (with the internal clearance of the rolling bearing set to 0 or negative). The reason for this is that by applying preload, the load area of the rolling bearing can be widened. As a result, during operation, the fluctuation of the load applied to each rolling element that alternately passes through this load area and non-load area This is because the width can be reduced (maximum load can be reduced). Furthermore, the rigidity of the rolling bearing can be increased, and deformation and vibration when an external force is applied can be suppressed. However, in the case of a rolling bearing that supports the main shaft, it is difficult to adopt a configuration in which preload is applied by a conventionally known method of constant position preload or constant pressure preload. The reason for this is as follows.

  That is, since the wind turbine generator is used in a natural environment, for example, when the operation is suddenly started from a state where it has been stopped for a long time in winter, for example, between the inner ring and the outer ring constituting the rolling bearing. A large temperature difference occurs. Therefore, if the preload is applied by the fixed position preload method, the preload of the rolling bearing may become excessive when a large temperature difference occurs between the inner ring and the outer ring as described above. If the preload becomes excessive in this way, the durability life of the rolling bearing may be reduced. For this reason, it is difficult to adopt a configuration in which a preload is applied by a fixed position preload method. On the other hand, when preload is applied by the constant pressure preload method, the preload of the rolling bearing can be kept constant at all times, so even if a large temperature difference occurs between the inner ring and the outer ring as described above, The bearing preload is never excessive. However, when preload is applied by the constant pressure preload method, the starting torque of the rolling bearing is increased, so that the startability of the rotor in a slight wind may be impaired (cut-in wind speed is increased). When the startability of the rotor is impaired in this way, the wind speed range (the width from the cut-in wind speed to the cut-out wind speed) that can be generated by the wind turbine generator is narrowed. For this reason, it is difficult to adopt a configuration in which preload is applied by the constant pressure preload method.

  In view of such circumstances, conventionally, a rolling bearing that supports the main shaft is used with an initial clearance (without applying preload). That is, when the rolling bearing is assembled at the place where it is used, the relative position in the axial direction of the inner ring and outer ring in the assembled state, and when these inner ring and outer ring are tightened in the axial direction with nuts, tightening is required. Considering the amount of expansion involved, and the load and temperature changes during use, the initial clearance of this rolling bearing is set so that excessive preload is not applied to the rolling bearing even in the worst case. I try to do it. Therefore, this rolling bearing is often operated with a positive internal gap during use.

  However, when the rolling bearing is operated with a positive internal gap in this way, the rolling bearing is compared with a case where the rolling bearing is operated with a zero or negative internal gap (operated with a preload applied). The load range is narrowed, and the fluctuation range of the load applied to each rolling element that alternately passes through the load range and the non-load range is increased during operation (the maximum load is high). Furthermore, the rigidity of the rolling bearing is reduced. For example, when the load applied to the rotor fluctuates drastically in a strong wind, an impact load is applied to the rolling surface or the raceway surface, or vibration generated in the rolling bearing is generated. It can grow. These are not preferable in securing the durable life of the rolling bearing.

In the above description, the problem that occurs with the rolling bearing that supports the main shaft has been taken up. However, such a problem also occurs with the rolling bearing that supports the rotating shaft that constitutes the transmission. .
As prior art documents related to the present invention, there are the following patent documents 4 to 7 in addition to the aforementioned patent documents 1 to 3.

JP-A-2-157383 Japanese Patent Laid-Open No. 10-96463 JP 2002-221263 A JP-A-9-108903 JP-A-6-58329 JP-A-8-166018 JP 2001-289295 A

  In view of the circumstances as described above, the rotation support device for wind power generators of the present invention is an invention for realizing a structure that can reduce the starting torque of a rolling bearing in a slight wind and can sufficiently ensure the durable life of the rolling bearing. It is a thing.

A rotation support device for a wind power generator according to the present invention includes a main shaft coupled and fixed to a rotation center portion of a rotor that rotates by receiving wind, or a rotation shaft constituting a transmission provided between the main shaft and a generator. And a housing and a rolling bearing that rotatably supports the rotating shaft or the main shaft with respect to the housing.
In particular, in the rotation support device for a wind turbine generator according to the present invention, it depends on at least one of the state of wind around the wind turbine generator (wind speed, wind direction) and the operating state of the wind turbine generator. Thus, preload control means for changing the magnitude of the preload applied to the rolling bearing is provided.

  According to the rotation support device for a wind power generator of the present invention configured as described above, it is always necessary for the rolling bearing in that state according to the wind state and the operation state around the wind power generator (does not become excessive). ) Preload can be applied. For this reason, it is possible to reduce the starting torque of the rolling bearing during no wind or light wind. As a result, the startability of the rotor constituting the wind power generator can be improved, and the wind speed range in which power generation by the wind power generator can be prevented from being narrowed. In other operations, the internal clearance of the rolling bearing can be set to 0 or negative as necessary. As a result, the width of the load area of the rolling bearing can be increased, and during operation, the fluctuation range of the load applied to each rolling element that alternately passes through the load area and the non-load area is reduced, and the maximum value of this load is increased. It can be kept low. At the same time, the rigidity of the rolling bearing can be increased. For example, it is possible to prevent an impact load from being applied to the rolling surface or the raceway surface or an increase in vibration generated in the rolling bearing even in a strong wind. Therefore, the durability life of the rolling bearing can be improved.

  Moreover, in the case of this invention, the preload of this rolling bearing can be changed in the state which assembled | attached the rolling bearing to the use place. For this reason, the initial clearance management at the time of manufacture of this rolling bearing, the fitting management when assembling at the place of use, and the tightening amount management when adopting the configuration in which the race ring is tightened in the axial direction by the nut are not strictly performed. I'll do it. Therefore, the manufacturing cost of the rolling bearing and the assembly cost of the rotation support device can be sufficiently suppressed.

  In addition, in the case of the present invention, when the rotation shaft constituting the transmission is adopted as the rotation shaft constituting the rotation support device, in addition to the above-described effects, a plurality of gears constituting the transmission even during torque fluctuation The tooth contact between each other can be stabilized. For this reason, the durable life of each gear can be improved.

Specifically, when carrying out the present invention, the configuration described in claim 2 can be adopted. That is, in the case of the configuration described in claim 2, the preload control means includes preload applying means, preload measuring means, and preload adjusting means.
Among these, the preload applying means applies a preload to the rolling bearing based on pressing the outer ring or the inner ring constituting the rolling bearing in the axial direction.
The preload measuring means measures the preload applied to the rolling bearing.
Further, the preload adjusting means is based on at least one of the following information: wind speed around the wind power generator, wind direction, rotational speed of the main shaft or rotating shaft, and temperature of the rolling bearing. In the direction of reducing the difference between the preload load determined in this way and the preload load measured by the preload measuring means (preferably zero) In addition, an operation command is issued to the preload applying means.

Moreover, when implementing this invention, the structure described in Claim 3 can be employ | adopted more specifically.
That is, in the case of the configuration described in claim 3, the target wind turbine generator has an ambient wind speed (for example, the speed of the head wind toward the rotor constituting the wind turbine generator) at a predetermined lower limit wind speed (cut). The generator is rotationally driven only when it is equal to or higher than the in-wind speed and is equal to or lower than a predetermined upper limit wind speed (cut-out wind speed).
The preload control means sets the magnitude of the preload applied to the rolling bearing to 0 when the ambient wind speed is less than the lower wind speed, and when the wind speed is equal to or higher than the lower wind speed and equal to or lower than the upper wind speed. When the internal clearance of the rolling bearing is 0 or negative, the internal clearance is changed to a negative size when the upper wind speed is exceeded.

  1-3 show Example 1 of the present invention. In the case of the present embodiment, the main shaft 1 constituting the wind power generator is rotatably supported inside a housing (not shown) by a pair of tapered roller bearings 2 and 2 that are spaced apart from each other in the axial direction. is doing. Each of these tapered roller bearings 2 and 2 has an inner ring 4 having a partially tapered convex inner ring raceway 3 on an outer peripheral surface, an outer ring 6 having a partially tapered concave outer ring raceway 5 on an inner peripheral surface, and these inner ring raceways 3. And a plurality of tapered rollers 7, 7 provided so as to be able to roll while being held by a cage (not shown) between the outer ring raceway 5 and the outer ring raceway 5. In such a pair of tapered roller bearings 2 and 2, the inner rings 4 and 4 are externally fitted onto the main shaft 1 by being fitted together on the back surface, and the outer rings 6 and 6 are attached to the housing. It is fitted with a gap fit.

  Further, on the part of the outer peripheral surface of the main shaft 1 adjacent to the opposite end surfaces of the inner rings 4, 4, the holding rings 8, 8 are respectively attached in the axial direction by means such as screwing or shrink fitting. It is fixed in a state that prevents displacement. Then, by restraining the end surfaces of the inner rings 4 and 4 opposite to each other by the restraining rings 8 and 8, the inner rings 4 and 4 are prevented from being displaced in directions away from each other in the axial direction. .

  A hydraulic cylinder 10 constituting a preload applying means 9 is provided between the end faces of the outer rings 6, 6 facing each other. The hydraulic cylinder 10 includes a cylinder 11 and a piston 12. Among these, the cylinder 11 has a U-shaped cross section and is formed in a cylindrical shape as a whole, and a cylindrical pressure oil space 13 is provided therein. The pressure oil can be supplied to and discharged from the pressure oil space 13 through a pressure oil passage 14 provided in a state where the pressure oil space 13 communicates with the space outside the cylinder 11 in the radial direction. The piston 12 has an annular shape as a whole, and a base end portion (right end portion in FIG. 1) is oil-tightly fitted inside the pressure oil space 13. In this state, the piston 12 is moved to the cylinder 11 by adjusting the supply / discharge amount of the pressure oil to the pressure oil space 13 by a hydraulic pump (not shown) constituting the preload applying means 9. On the other hand, it can be displaced in the axial direction.

  In such a hydraulic cylinder 10, one of the base end surfaces (the right end surface in FIG. 1) of the cylinder 11 (right side in FIG. 1) is disposed between the end surfaces facing each other of the outer rings 6, 6. The end surface of the piston 12 (the left end surface in FIG. 1) is brought into contact with the end surface of the outer ring 6 on the other side (the left end surface in FIG. 1). And in this state, based on increasing the amount of pressure oil supplied to the pressure oil space 13, the cylinder 11 and the piston 12 are displaced in directions away from each other in the axial direction, whereby the outer rings 6, 6 is pressed in the axial direction. A preload is applied to the tapered roller bearings 2 and 2 based on pressing the outer rings 6 and 6 in the axial direction.

  As described above, the magnitude of the preload applied to each tapered roller bearing 2, 2 can be changed as appropriate by adjusting the amount of pressure oil supplied to and discharged from the pressure oil space 13. In the case of the present embodiment, such a pressure oil supply / discharge amount adjustment command (operation control of the preload applying means 9) is performed by a control device 15 which is a preload adjusting means as shown in FIG. Is adopted.

The control device 15 includes information S ₁ relating to the wind speed around the wind power generator (speed of heading toward the rotor), information S ₂ relating to the rotational speed of the main shaft 1, and the tapered roller bearings 2 and 2. Information S ₃ related to the temperature of the inner ring 4 and the outer ring 6 and information S ₄ related to the preload applied to the tapered roller bearings 2 and 2 are input in real time. The information S ₁ about the wind speed, the wind direction and wind speed meter 16 supplied with the wind turbine generator (not shown in FIG. 1), information S ₂ related to the rotation speed of the spindle 1, assembled to the main shaft 1 By means of a rotational speed detector 17 (not shown in FIG. 1), information S ₃ relating to the temperature of the inner ring 4 and outer ring 6 is sent to a temperature sensor 18 (not shown in FIG. 1) assembled to the inner ring 4 and outer ring 6. ) To measure each. The information S ₄ regarding the preload of the tapered roller bearings 2 and 2 is based on the preload measuring means 19 including the hydraulic cylinder 10 and measuring the oil pressure in the hydraulic cylinder 10 (in advance). It is measured using the relationship between preload and hydraulic pressure, which was investigated by experiment. Note that the measurement of the information S ₄ regarding the preload can be performed using a conventionally known load converter using a strain gauge (see, for example, Patent Document 4).

At the time of use of the wind power generator, the control device 15 at each time point based on the information S ₁ about the wind speed, the information S ₂ about the rotational speed, and the information S ₃ about the temperature, which are inputted in real time as described above. Therefore, the magnitude of the preload to be applied to the tapered roller bearings 2 and 2 is determined. In this case, basically, the magnitude of the preload to be applied is determined as follows based on the information S ₁ regarding the wind speed.

  That is, as shown in FIG. 3, when the wind speed is 0 (no wind) or more and less than the cut-in wind speed, the magnitude of the preload to be applied is determined to be 0. As a result, the starting torque of the tapered roller bearings 2 and 2 is minimized, the startability of the rotor in the wind speed range is improved, and the wind speed range in which the wind power generator can generate power is prevented from being narrowed. Also, if the wind speed is above the cut-in wind speed and less than the rated wind speed (the wind speed that exists between the cut-in wind speed and the cut-out wind speed and the wind power generator can generate power most efficiently) The magnitude of the preload to be determined is determined to be a magnitude (light preload) at which the internal gap between the tapered roller bearings 2 and 2 becomes 0 or negative according to the wind speed. As a result, the rigidity of the tapered roller bearings 2 and 2 required in the wind speed range is ensured. Further, when the wind speed is equal to or higher than the rated wind speed and less than the cut-out wind speed, the magnitude of the preload to be applied is set so that the internal clearance between the tapered roller bearings 2 and 2 is negative depending on the wind speed. Is determined to be {medium preload (> light preload)}. As a result, the rigidity of the tapered roller bearings 2 and 2 required in the wind speed range is ensured. Further, when the wind speed is equal to or higher than the cut-out wind speed, the magnitude of the preload to be applied is determined to a larger value {heavy preload (> medium preload)} according to the wind speed. Thus, the rigidity of the tapered roller bearings 2 and 2 is ensured to be larger, and the rolling surfaces of the tapered roller bearings 2 and 2 and It is possible to prevent an impact load from being applied to the raceway surface or a vibration generated by each of these tapered roller bearings 2 and 2 from increasing.

However, in any of the above-described wind speed ranges, a specific magnitude of the preload is determined while sufficiently considering the information S ₂ regarding the rotational speed and the information S ₃ regarding the temperature. That is, when the magnitude of the preload to be applied is determined based only on the information S ₁ relating to the wind speed, the tapered roller bearings 2 are used when, for example, sudden torque fluctuations or excessive inner / outer ring temperature differences occur. The rolling element load of 2 may be excessive. Therefore, when a sudden torque fluctuation or an excessive inner / outer ring temperature difference occurs during operation, these situations are detected based on the information S ₂ on the rotational speed and the information S ₃ on the temperature, and In this way, the magnitude of the preload to be specifically applied is determined so that the rolling element load does not become excessive.

Then, the control device 15 makes the preload so that the difference between the magnitude of the preload determined as described above and the information S ₄ (the current magnitude of the preload) regarding the preload is zero. An operation command is given to the applying means 9 (operation control of the preload applying means 9 is performed by feedback control).

  As described above, according to the rotation support device for a wind power generator of this embodiment, the startability of the rotor is improved during no wind or light wind, and the wind speed range in which the wind power generator can generate power is prevented from being narrowed. it can. Further, in any wind condition and operating condition, the internal clearance between the tapered roller bearings 2 and 2 can be set to 0 or negative as necessary. As a result, the width of the load zone of each of these tapered roller bearings 2 and 2 can be widened, and the fluctuation range of the load applied to each of the tapered rollers 7 and 7 that alternately pass through the load zone and the non-load zone during operation is reduced. In addition, the maximum value of this load can be kept low. At the same time, the rigidity of the tapered roller bearings 7 and 7 can be increased. For example, an impact load is applied to the rolling surface and the raceway surface even in a strong wind, or the tapered roller bearings 2 and 2 are generated. It is possible to prevent the vibration to be increased. Of course, even in these cases, it is possible to prevent the preload of the tapered roller bearings 2 and 2 from becoming excessive. Therefore, the durable life of each tapered roller bearing 2 and 2 can be improved.

  In the case of the present embodiment, the preload of the tapered roller bearings 2 and 2 can be changed in a state in which the tapered roller bearings 2 and 2 are assembled at the place of use. For this reason, it is not necessary to strictly perform the initial clearance management at the time of manufacture of each of these tapered roller bearings 2 and 2 and the fitting management at the time of assembling at the place of use. Therefore, the manufacturing cost of the tapered roller bearings 2 and 2 and the assembly cost of the rotation support device can be sufficiently suppressed.

  Next, FIG. 4 shows Embodiment 2 of the present invention. In the case of this embodiment, the number of tapered roller bearings 2 for adjusting the preload is set to one. Accordingly, the base end face (the right end face in FIG. 4) of the cylinder constituting the hydraulic cylinder 10 is brought into contact with the end face of the housing 20 which is a fixed member. Other configurations and operations are the same as those of the first embodiment described above.

  In the case of carrying out the present invention, the rolling bearing is not limited to the tapered roller bearing employed in each of the embodiments described above, and other types of rolling bearings such as an angular ball bearing can also be employed. Further, the preload applying means is not limited to the structures of the above-described embodiments, and various structures such as the structures described in Patent Documents 5 and 6 can be employed. In this case, the device for applying the preload is not limited to a hydraulic type, but may be a mechanical type, an electromagnetic type, or a device using a piezoelectric element. Further, the control by the preload control means can be performed using a neurocomputer as described in Patent Document 7, for example.

Sectional drawing of the rotation support part which shows Example 1 of this invention. The block diagram which shows the relationship between a control apparatus and another apparatus. The figure which shows the relationship between the wind speed around a wind power generator, and the preload applied to a tapered roller bearing. Sectional drawing of the rotation support part which shows Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main shaft 2 Tapered roller bearing 3 Inner ring raceway 4 Inner ring 5 Outer ring raceway 6 Outer ring 7 Tapered roller 8 Retaining ring 9 Preloading means 10 Hydraulic cylinder 11 Cylinder 12 Piston 13 Pressure oil space 14 Pressure oil passage 15 Controller 16 Wind direction and anemometer 17 Rotational speed detector 18 Temperature sensor 19 Preload measuring means 20 Housing

Claims (3)

  A main shaft that is coupled and fixed to a rotation center of a rotor that rotates by receiving wind, or a rotation shaft that constitutes a transmission provided between the main shaft and a generator, a housing, and the rotation shaft or the main shaft. In a rotation support device for a wind power generator provided with a rolling bearing that is rotatably supported with respect to the wind power generation device, the wind power generation device has at least one of a state of wind around the wind power generation device and an operation state of the wind power generation device. A wind power generator rotation support device comprising preload control means for changing the magnitude of the preload applied to the rolling bearing accordingly.   The preload control means includes a preload applying means, a preload measuring means, and a preload adjusting means, and the preload applying means includes a rolling bearing based on pressing an outer ring or an inner ring constituting the rolling bearing in the axial direction. The preload measuring means measures the preload applied to the rolling bearing, and the preload adjusting means has the same wind direction as the wind speed around the wind turbine generator. And the magnitude of the preload to be applied to the rolling bearing based on at least one of the information on the rotational speed of the main shaft or the rotating shaft and the temperature of the rolling bearing. The operation command is given to the preload applying means in a direction to reduce the difference between the preload load and the preload load measured by the preload measuring means. Force power generation system for a rotary support device.   The wind turbine generator rotates the generator only when the surrounding wind speed is equal to or higher than a predetermined lower limit wind speed and lower than a predetermined upper limit wind speed, and the preload control means is configured to apply a preload load applied to the rolling bearing. The size is set to 0 when the ambient wind speed is less than the lower limit wind speed, and when the wind speed is equal to or higher than the lower limit wind speed and less than or equal to the upper limit wind speed, the internal clearance of the rolling bearing is 0 or negative. The rotation support device for a wind turbine generator according to any one of claims 1 to 2, wherein when the upper wind speed is exceeded, the internal gap is changed to a negative size.

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