Patent Application
20110182735
The present invention relates to a windmill pitch driving apparatus that can be provided in a windmill and used as a driving apparatus for controlling the pitch angle of a blade that is rotatably provided on a main shaft portion of the windmill.
Windmills may be provided with a windmill pitch driving apparatus that is used as a driving apparatus for controlling the pitch angle of a blade that is rotationally provided on the main shaft portion of the windmill. With recent trends such as increased power generating capacities of windmills and increased blade diameters, a situation has arisen where there is a demand for a windmill pitch driving apparatus with high-output specifications having improved output torque. Meanwhile, windmill pitch driving apparatuses are also required to have a smaller configuration because there is only limited space in a windmill for installing the windmill pitch driving apparatuses.
In view of this, an eccentric speed reducer for yaw drive for causing the nacelle of a windmill to turn around, as disclosed in PTL 1, is known as an example of a speed reducer capable of achieving a high speed reduction ratio, which is necessary to improve output torque and reduce size. In the speed reducer disclosed in PTL 1, an input shaft (62) that receives the driving force of an electric motor extends through an upper cover (14), and an oil seal (50) is disposed between the input shaft and the upper cover. The upper cover has a bulging portion (71) formed by part of the upper cover bulging upward, and with this configuration, the oil level of lubricating oil enclosed in the casing is raised to this bulging portion so as to be above the level of the oil seal.
The application of the speed reducer disclosed in PTL 1 as a windmill pitch driving apparatus is considered in order to improve the output torque of the windmill pitch driving apparatus as well as to reduce the size thereof. However, the speed reducer disclosed in PTL 1 is configured such that the level of the lubricating oil in the casing is above the level of the oil seal disposed between the upper cover and the input shaft, and therefore a large amount of lubricating oil is enclosed in the casing. The use of the speed reducer disclosed in PTL 1 as a windmill pitch driving apparatus thus has the problem that the weight of the windmill pitch driving apparatus is caused to increase. In addition, in the case of the speed reducer disclosed in PTL 1, there is the problem that the upper cover provided with the bulging portion formed so as to bulge upward causes an increase in the axial dimension (the dimension in the axial direction of the output shaft), which is disadvantageous to size reduction.
In view of the foregoing circumstances, it is an object of the present invention to provide a windmill pitch driving apparatus that is capable of achieving improved output torque and reduced size as well as reduced weight.
In order to achieve the above-described object, a windmill pitch driving apparatus according to a first aspect of the present invention is provided in a windmill and used as a driving apparatus for controlling a pitch angle of a blade that is rotatably provided on a main shaft portion of the windmill, and includes a casing, a cover fixed to the casing so as to cover an opening at an end of the casing, an electric motor being attachable to the cover, a plurality of internal tooth pins disposed on an inner circumference of the casing and formed as pin-shaped members, an external tooth gear housed in the casing and provided with external teeth formed on its outer circumference that mesh with the internal tooth pins, an input shaft extending through the cover and configured to receive a driving force of the motor, a seal member disposed between the cover and the input shaft, a crankshaft extending through a crank hole formed in the external tooth gear, and configured to rotate with the driving force transmitted from the input shaft so as to let the external tooth gear rotate eccentrically, a base carrier holding the crankshaft on one end side, an end carrier holding the crankshaft on the other end side, a strut disposed between the base carrier and the end carrier so as to provide a connection between the base carrier and the end carrier, an output shaft fixed to the base carrier and provided with a pinion, a pair of crankshaft bearings, one of which rotatably holds the crankshaft on the one end side with respect to the base carrier and the other of which rotatably holds the crankshaft on the other end side with respect to the end carrier, and an external tooth bearing disposed in the crank hole and rotatably holding the crankshaft with respect to the external tooth gear, wherein lubricating oil is enclosed in the casing such that the crankshaft bearings and the external tooth bearing are immersed in the lubricating oil during a single rotation of the main shaft portion, and in a state in which the motor is located on the upper side and an axis of the output shaft corresponds to a vertical direction, an oil level of the lubricating oil enclosed in the casing is below the level of the seal member and such that at least part of a driving force transmission path from the input shaft to the crankshaft is exposed to air enclosed in the casing.
According to this aspect of the present invention, the windmill pitch driving apparatus is configured as an eccentric speed reducer provided with the external tooth gears, which rotate eccentrically. Accordingly, a high speed reduction ratio is ensured, and improved output torque is achieved. The windmill pitch driving apparatus, which is configured as an eccentric speed reducer, is capable of achieving a high speed reduction ratio with a small configuration. Furthermore, in the windmill pitch driving apparatus according to this aspect of the present invention, lubrication of the bearings in the casing is ensured, because the lubricating oil is enclosed in the casing such that the crankshaft bearings and the external tooth bearings are immersed in the lubricating oil during a single rotation of the main shaft portion of the windmill. With this windmill pitch driving apparatus in a vertical orientation in which the motor is located on the upper side and the axis of the output shaft is oriented in the vertical direction, the oil level of the lubricating oil in the casing is below the level of the seal member disposed between the cover and the input shaft and such that at least part of the driving force transmission path is exposed to the air in the casing. Accordingly, with effective use of the properties of the windmill pitch driving apparatus, the amount of the lubricating oil in the casing can be reduced while ensuring lubrication of the bearings in the casing, and as a result, the weight of the windmill pitch driving apparatus can be reduced. Furthermore, since the oil level of the lubricating oil is below the level of the seal member with the windmill pitch driving apparatus in the aforementioned vertical orientation, the cover does not need to partly bulge outward greatly as in the speed reducer disclosed in PTL 1, and accordingly an increase in the axial dimension, which is a disadvantage to downsizing, can be suppressed.
It is thus possible according to this aspect of the present invention to provide a windmill pitch driving apparatus that is capable of achieving improved output torque and reduced size as well as reduced weight.
A windmill pitch driving apparatus according to a second aspect of the present invention is the windmill pitch driving apparatus according to the first aspect of the present invention, which further includes a crank driving gear fixed to the crankshaft on the other end side and configured to receive the driving force transmitted from the input shaft, wherein the lubricating oil is enclosed in the casing such that in a state in which the motor is located on the upper side and the axis of the output shaft corresponds to the vertical direction, the oil level of the lubricating oil enclosed in the casing is below the level of the underside of the crank driving gear.
According to this aspect of the present invention, the windmill pitch driving apparatus is configured such that, in its aforementioned vertical orientation, the oil level of the lubricating oil in the casing is below the level of the underside of the crank driving gear. Accordingly, with the windmill pitch driving apparatus in the aforementioned vertical orientation, there is a sufficient volume of stored air above the crank driving gear. This suppresses an increase in pressure in the windmill pitch driving apparatus and suppresses leakage of the lubricating oil in the casing to the outside. Furthermore, it is possible with the above-described configuration to readily achieve a configuration in which a sufficient volume of stored air is ensured, and therefore the axial distance between the crank driving gear and the cover can be further shortened. This allows a further reduction in the axial dimension of the windmill pitch driving apparatus (that is, the axis of the windmill pitch driving apparatus can be shortened).
According to the present invention, it is possible to provide a windmill pitch driving apparatus that is capable of achieving improved output torque and reduced size as well as reduced weight.
The following is a description of an embodiment for carrying out the present invention with reference to the drawings. An embodiment of the present invention is widely applicable as a windmill pitch driving apparatus that can be provided in a windmill and used as a driving apparatus for controlling the pitch angle of a blade that is rotatably provided on a main shaft portion of the windmill.
Furthermore, the pitch driving apparatus 1 is disposed such that the pinion 16 of the output shaft 15 disposed on one end side of the pitch driving apparatus 1 meshes with the ring gear 107 of the blade 105. The pitch driving apparatus 1 reduces the speed of the driving force input from the motor 108 disposed on the other end side of the pitch driving apparatus 1 and outputs the driving force to the pinion 16, thereby causing the blade 105 to rotate about its shaft center with respect to the hub 104, together with the ring gear 107 that meshes with the pinion 16. The pitch driving apparatus 1 is thereby configured to control the pitch angle of the blade 105. Note that in the following description, the output side of the pitch driving apparatus 1, on which the output shaft 15 is disposed, is referred to as “one end side”, and the input side thereof, to which the motor 108 is attached, is referred to as “the other end side”.
As shown in
As shown in
As shown in
As shown in
Multiple internal tooth pins 17 are disposed on the inner circumference of the casing 11 in a state in which they are fitted in and attached to pin grooves formed on the inner circumference of the casing 11. The internal tooth pins 17 (
The spur gears 20 are disposed such that the direction of their shaft centers is parallel to the axis P, and are fixed to the ends of multiple crankshafts 21 provided on the other end side. The spur gears 20 are disposed so as to mesh with a gear portion of the input shaft 13 formed on the one end side, and constitute a crank driving gear in the present invention, to which the driving force of the input shaft 13 is transmitted.
Multiple (three, for example) crankshafts 21 are circumferentially disposed around the axis P at equal angle intervals, such that their axial direction is parallel to the axis P. Each crankshaft 21 (
The crankshaft bearings 27 are provided as a pair of crankshaft bearings 27, one of which rotatably holds a crankshaft 21 on the one end side and the other of which rotatably holds the crankshaft 21 on the other end side. Each pair of crankshaft bearings 27 is composed of a crankshaft bearing 27a that rotatably holds a crankshaft 21 on the one end side with respect to the base carrier 23, which will be discussed later, and a crankshaft bearing 27b that rotatably holds the crankshaft 21 on the other end side with respect to the end carrier 24, which will be discussed later. In the present embodiment, both of the crankshaft bearings 27a and 27b are configured as tapered roller bearings.
The external tooth gears 22 include a first external tooth gear 22a and a second external tooth gear 22b that are housed in the casing 11 in parallel arrangement. As mentioned above, the first external tooth gear 22a and the second external tooth gear 22b have the crank holes 30 formed as circular holes, through which the crankshafts 21 extend. Each external tooth gear (22a, 22b) of the external tooth gears 22 further has formed therein, in addition to the crank holes 30, strut holes 31 through which the struts 25 discussed later extend. Note that the first external tooth gear 22a and the second external tooth gear 22b are disposed such that the positions of their crank holes 30 correspond to each other and the positions of their strut holes 31 correspond to each other, in the direction parallel to the axis P. Corresponding to the struts 25, multiple (three, for example) strut holes 31 are disposed circumferentially of the external tooth gears 22 at equal angle intervals. The strut holes 31 and the crank holes 30 are alternately formed circumferentially of the external tooth gears 22. Note that the struts 25 extend through the strut holes 31 in a loosely fitted state without contact.
The external teeth 29 for meshing with the internal tooth pins 17 are provided on the outer circumference of each of the first external tooth gear 22a and the second external tooth gear 22b. The external teeth 29 of the first external tooth gear 22a and the external teeth 29 of the second external tooth gear 22b are provided such that their numbers are at least one smaller than the number of the internal tooth pins 17. Accordingly, with this configuration, the meshing of the external teeth 29 of the external tooth gears 22 (the first external tooth gear 22a and the second external tooth gear 22b) with the internal tooth pins 17 is shifted each time the crankshafts 21 rotate, and thereby the external tooth gears 22 (the first external tooth gear 22a and the second external tooth gear 22b) oscillate and rotate eccentrically.
The external tooth bearings 28 include an external tooth bearing 28a disposed in the crank hole 30 of the first external tooth gear 22a, and an external tooth bearing 28b disposed in the crank hole 30 of the second external tooth gear 22b. Both of the external tooth bearings 28 (28a and 28b) are configured as cylindrical roller bearings or needle roller bearings. In each crank hole 30, the external tooth bearing 28a rotatably holds the first eccentric portion 21a of the crankshaft 21 with respect to the first external tooth gear 22a, and the external tooth bearing 28b rotatably holds the second eccentric portion 21b of the crankshaft 21 with respect to the second external tooth gear 22b.
The base carrier 23 is integrally formed at its one end with a body shaft portion 15a of the output shaft 15 and disposed in the casing 11. Meanwhile, crank holding holes 32 are formed on the other end side with respect to the base carrier 23. With the crank holding holes 32, the base carrier 23 rotatably holds the end of each crankshaft 21 on the one end side via the crankshaft bearings 27a. The crank holding holes 32 are circumferentially formed around the axis P at equal angle intervals.
The end carrier 24 is coupled to the base carrier 23 via the struts 25 and provided as a disc-shaped member. The end carrier 24 has crank holding holes 33 formed as through holes and provided circumferentially around the axis P at equal angle intervals. With the crank holding holes 33, the end carrier 24 rotatably holds the crankshafts 21 on the other end side via the crankshaft bearings 27b. Note that the axial position of the crankshaft bearings 27b on the other end side is defined under pressured conditions by a ring-shaped stop member fitted in the crank holding holes 33.
The struts 25 are disposed between the base carrier 23 and the end carrier 24 and provided as pillar-shaped members that provide a connection between the base carrier 23 and the end carrier 24. Multiple (three, for example) struts 25 are circumferentially disposed around the axis P at equal angle intervals, such that their axial direction is parallel to the axis P. Note that the struts 25 and the crankshafts 21 are alternatively disposed circumferentially around the axis P. Each strut 25 is integrally formed with the base carrier 23 and provided so as to project out from the base carrier 23 on the other end side. In each strut 25, a strut bolt hole 34 provided with an internal thread portion formed on its inner circumference is formed, opening on the other end side and facing a through hole for inserting a bolt formed in the end carrier 24. With this configuration, strut bolts 35 are inserted in the strut bolt holes 34 from the other end side with respect to the end carrier 24, and the external thread portions of the strut bolts 35 and the internal thread portions of the strut bolt holes 34 are threadedly engaged with one another, so the end carrier 24 and the base carrier 23 are coupled to each other via the struts 25.
The main bearings 26 are provided as a pair of main bearings 26 that rotatably holds the base carrier 23, the end carrier 24, and the output shaft 15 with respect to the casing 11. The pair of main bearings 26 includes a main bearing 26a that rotatably holds the body shaft portion 15a of the output shaft 15 with respect to the casing 11, and a main bearing 26b that rotatably holds the end carrier 24 with respect to the casing 11. In the present embodiment, the main bearing 26a is configured as a tapered roller bearing, and the main bearing 26b is configured as a ball bearing. Note that the main bearing 26a is engaged on the one end side with a positioning member 36 attached and fixed to the outer circumference of the body shaft portion 15a of the output shaft 15, and is positioned on the other end side under pressured conditions in engagement with a stepped portion of the inner circumference of the casing 11. On the other hand, the main bearing 26b is engaged on the one end side with a stepped portion of the inner circumference of the casing 11, and is positioned on the other end side in engagement with an edge portion of the outer circumference of the end carrier 24. In the pitch driving apparatus 1, the positioning member 36 is fixed to the body shaft portion 15a of the output shaft 15, and the base carrier 23 and the end carrier 24 are fastened with the strut bolts 35 via the struts 25. Accordingly, the output shaft 15, the base carrier 23, and the end carrier 24 hold the casing 11 therebetween via the pair of main bearings 26, and the output shaft 15, the base carrier 23, and the end carrier 24 are rotatably held with respect to the casing 11.
As mentioned above, the output shaft 15 shown in
In the pitch driving apparatus 1, lubricating oil is enclosed in the casing 11. In
Next is a description of the operation of the above-described pitch driving apparatus 1 for controlling the pitch angle of the blade 105. The pitch driving apparatus 1 is actuated with the operation of the motor 108. When the operation of the motor 108 is started, the input shaft 13 rotates together with the output shaft of the motor 108 (not shown) and the spur gears 20 that mesh with the gear portion of the input shaft 13 rotate. When the spur gears 20 rotate, the crankshafts 21 fixed to the spur gears 20 rotate together with their first and second eccentric portions (21a and 21b). Accordingly, a load is applied from the first and second eccentric portions (21a and 21b) respectively to the first and second external tooth gears (22a and 22b), and the first and second external tooth gears (22a and 22b) oscillate and rotate eccentrically while shifting their meshing with the internal tooth pins 17. With the eccentric rotation of the first and second external tooth gears (22a and 22b), the crankshafts 21, which are rotatably held against the first and second external tooth gears (22a and 22b), orbits the axis P while rotating on their own axes. This orbital movement of the crankshafts 21 causes the output shaft 15 to rotate together with the base carrier 23 and the end carrier 24, which are coupled to each other via the struts 25 and rotatably hold the crankshafts 21 via the crankshaft bearings (27a and 27b), and therefore a high torque is output from the pinion 16. Accordingly, the ring gear 107 is driven by the pinion 16, and the pitch angle of the blade 105 is controlled.
Furthermore, as mentioned above, when the hub 104 rotates once, the pitch driving apparatus 1 rotates once around the shaft center of the hub 104 together with the blade 105, so the angle formed by the axis P of the pitch driving apparatus 1 relative to the vertical direction rotates through 360 degrees. While the hub 104 rotates once in this way, in the pitch driving apparatus 1, the lubricating oil in the casing 11 is supplied to all the meshing portions of the gear mechanisms and all the bearings in the casing 11.
According to the pitch driving apparatus 1 described above, the pitch driving apparatus 1 is configured as an eccentric speed reducer provided with the external tooth gears 22, which rotate eccentrically. Accordingly, a high speed reduction ratio is ensured and improved output torque is achieved. The pitch driving apparatus 1, which is configured as an eccentric speed reducer, is capable of achieving a high speed reduction ratio with a small configuration. Furthermore, in the pitch driving apparatus 1, lubrication of the bearings in the casing 11 is ensured, because the lubricating oil is enclosed in the casing 11 such that the crankshaft bearings (27a and 27b) and the external tooth bearings (28a and 28b) are immersed in the lubricating oil during a single rotation of the hub 104 of the windmill 101. With the pitch driving apparatus 1 in a vertical orientation in which the motor 108 is located on the upper side and the axis P of the output shaft 15 is oriented in the vertical direction, the oil level 40 of the lubricating oil in the casing 11 is below the level of the seal member 19a disposed between the cover 12 and the input shaft 13 and such that at least part of the driving force transmission path is exposed to the air in the casing 11. Accordingly, with effective use of the properties of the pitch driving apparatus 1, the amount of the lubricating oil in the casing 11 can be reduced while ensuring lubrication of the bearings in the casing, and as a result, the weight of the pitch driving apparatus 1 can be reduced. Furthermore, since the oil level 40 of the lubricating oil is below the level of the seal member 19a with the pitch driving apparatus 1 in the aforementioned vertical orientation, the cover 12 does not need to partly bulge outward greatly as in the speed reducer disclosed in PTL 1, and accordingly an increase in the axial dimension, which is a disadvantage to downsizing, can be suppressed.
It is thus possible according to the present embodiment to provide a windmill pitch driving apparatus 1 that is capable of achieving improved output torque and reduced size as well as reduced weight.
Furthermore, the pitch driving apparatus 1 is configured such that, in its aforementioned vertical orientation, the oil level 40 of the lubricating oil in the casing 11 is below the level of the underside of the spur gears 20. Accordingly, with the pitch driving apparatus 1 in the aforementioned vertical orientation, there is a sufficient volume of stored air above the spur gears 20. This suppresses an increase in pressure in the pitch driving apparatus 1 and suppresses leakage of the lubricating oil in the casing 11 to the outside. Furthermore, it is possible with this configuration to readily achieve a configuration in which a sufficient volume of stored air is ensured, and therefore the axial distance between the spur gears 20 and the cover 12 can be further shortened. This allows a further reduction in the axial dimension of the pitch driving apparatus 1 (that is, the axis of the pitch driving apparatus 1 can be shortened).
Although the above has been a description of the embodiment of the present invention, the present invention is not intended to be limited to the above-described embodiment, and various modifications may be made within the scope recited in the claims. For example, the windmill pitch driving apparatus may be provided with a centercrank speed reduction portion in which the crankshafts are disposed on the axis of the output shaft. The struts, which provide a connection between the base carrier and the end carrier, may be formed separately from the base carrier. The numbers of crankshafts and the numbers of struts may be different from the example of the present embodiment. The type of each bearing may be changed where appropriate for carrying out the present invention. The position of the oil level of the lubricating oil in the casing in a state in which the motor is located on the upper side and the axis of the output shaft corresponds to the vertical direction may be different from the example of the present embodiment, and it may be below or above the level illustrated in the present embodiment. The crank driving gear is not necessarily a spur gear. Furthermore, a configuration is possible in which the driving force is directly input from the input shaft to the crankshafts, or in which the driving force is transmitted via multiple gear components between the input shaft and the crankshafts.
The present invention is widely applicable as a windmill pitch driving apparatus that can be provided in a windmill and used as a driving apparatus for controlling the pitch angle of a blade that is rotatably provided on the main shaft portion of the windmill.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008-258986 | Oct 2008 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2009/004802 | 9/24/2009 | WO | 00 | 3/30/2011 |
