The present invention relates to a lubricant heating mechanism, a gear mechanism, and a wind turbine generator using the same, and more particularly, to a heating mechanism for heating lubricant when an equipment is started in an extremely cold environment.
There arises a necessity to heat lubricant, when a wind turbine generator or other equipment is used in an extremely cold environment. The viscosity of the lubricant increases in an extremely cold environment, and an excessively increase in the viscosity of the lubricant enhances the load of a lubricant circulation pump, and may cause malfunction of the circulation pump. To address this, the lubricant is heated by a heater, when the temperature of the lubricant is low. For example, US Patent Application Publication No. 2009/0191060 A1 (Patent Document 1) discloses a technique for providing a heater in an exhaust pipe which evacuates lubricant from a gearbox to a pump.
One problem is that it takes a long time to reheat the lubricant in an equipment tank when the equipment stops operating in an extremely cold environment. In an equipment used in an extremely cold environment, a heater is provided in a lubricant tank to heat lubricant; however, the viscosity of the lubricant increases when the lubricant accumulated in the equipment tank is cooled after the machine stops operating in the extremely cold environment. Occurrence of convection is suppressed in the cooled lubricant, which has a high viscosity; convection occurs to the lubricant right on the heater and the lubricant right on the heater is promptly heated, while no convection occurs laterally and below the heater and the lubricant lateral of and below the heater is difficult to be heated.
Particularly, this problem is serious when a suction port drawing out the lubricant from the equipment tank into a lubricant pump is positioned laterally of the heater because of the equipment layout. It takes long time to restart the lubricant pump, since the lubricant near the suction port is not heated.
It is, therefore, an object of the present invention to provide a lubricant heating mechanism capable of reducing time necessary to restart a lubricant pump after the lubricant in an equipment tank is cooled, and a wind turbine generator using such lubricant heating mechanism.
In an aspect of the present invention, a lubricant heating mechanism is provided with: a tank accumulating therein lubricant; a lubricant pump; a heater provided in the tank to heat the lubricant; and a baffle plate at least partially covering the heater. The tank is provided with a suction port drawing out the lubricant from the tank to the lubricant pump. The baffle plate is provided to convect the heated lubricant toward the suction port.
When the lubricant heating mechanism further includes a gear, it is preferable that the baffle plate is provided to cover a lower portion of the gear and to function as an oil pan holding the lubricant near the gear.
The baffle plate is preferably provided away from a sidewall of the tank, the sidewall having the suction port provided thereon.
In another aspect of the present invention, a lubricant heating mechanism is provided with: a tank accumulating therein lubricant; a lubricant pump; and a heater provided in said tank to heat said lubricant. The tank is provided with a suction port drawing out the lubricant from the tank to the lubricant pump, the suction port being provided laterally of the heater. The lubricant located near the suction port is heated faster than the lubricant near a portion above the heater on a liquid surface of the lubricant.
In still another aspect of the present invention, a gear mechanism is provided with a tank portion accumulating therein lubricant; a gear; an oil pan provided to cover a lower portion of the gear to hold the lubricant near the gear; and a heater provided in the tank portion to heat the lubricant. The tank is provided with a suction port drawing out the lubricant from the tank to a lubricant pump. The oil pan covers the heater at least partially and functions as a baffle plate convecting the heated lubricant toward the suction port.
In still another aspect of the present invention, a wind turbine generator is provided with: a main shaft supporting a wind turbine rotor and provided rotatably; a gear box having an input shaft connected to the main shaft; and a generator connected to an output shaft of the gear box. The gear box includes: a housing including a tank portion accumulating therein lubricant; a gear provided inside the housing; an oil pan provided to cover a lower portion of the gear, and holding the lubricant near the gear; and a heater provided in the tank portion. The housing is provided with a suction port drawing out the lubricant from the tank portion to a lubricant pump. The oil pan covers the heater at least partially and functions as a baffle plate convecting the lubricant toward the suction port.
A heater 4 for heating the lubricant is provided inside the equipment tank 1. The heater 4 is used to heat the lubricant when the temperature of the lubricant inside the equipment tank 1 is low. The viscosity of the lubricant increases, when the equipment stops operating in an extremely cold state and the temperature of the lubricant falls. The lubricant pump 2 cannot operate when the viscosity of the lubricant is excessively increased. To address this, the lubricant pump 2 is started after the heater 4 sufficiently heats the lubricant, at the time of restarting the equipment.
In this embodiment, a baffle plate 5 for controlling the convection of the lubricant is provided above the heater 4. The baffle plate 5 is shaped and located to convect the lubricant toward the suction port 6. This baffle plate 5 contributes to efficiently heat the lubricant in the region necessary for starting and to promptly restart the lubricant pump 2. There is no need to heat the lubricant entirely in starting the lubricant pump 2; it is actually the lubricant near the suction port 6 that is necessary to be heated. Therefore, in this embodiment, the baffle plate 5 is provided to thereby promptly heat the lubricant near the suction port 6; this allows promptly starting the lubricant pump 2. The function of the baffle plate 5 will be described below in detail.
As shown in
In this embodiment, as shown in
The shape and position of the baffle plate 5 may be variously changed. For example, although the baffle plate 5 is shaped and located to completely cover up the upper portion of the heater 4 in
As shown in
The structure of the lubricant heating mechanism stated above is suited to be applied to various mechanisms in a wind turbine generator used in a cold region, particularly suited to be applied to a gear box. The structure of the gear box to which the lubricant heating mechanism according to the present invention is applied will be described below.
As shown in
The gear speed-up mechanism 17b includes a first rotational shaft 31 connected to the sun gear shaft 26, a first spur gear 32 connected to the first rotational shaft 31, a second spur gear 33, a second rotational shaft 34 connected to the second spur gear 33, a third spur gear 35 connected to the second rotational shaft 34, a fourth spur gear 36, and an output shaft 37 connected to the fourth spur gear 35. The first rotational shaft 31, the second rotational shaft 34, and the output shaft 37 are rotatably supported by bearings 38, 39, and 40 provided in the housing 19, respectively. Further, the first spur gear 32 is engaged with the second spur gear 33, and the third spur gear 35 is engaged with the fourth spur gear 36. In the gear speed-up mechanism 17b thus structured, when the sun gear shaft 26 is rotated, the rotation of the sun gear shaft 26 is transmitted to the first spur gear 32, the second spur gear 33, the third spur gear 35, and the fourth spur gear 36, and the output shaft 37 connected to the fourth spur gear 36 are acceleratedly rotated. That is, as a whole of the gear box 17, when the input shaft 21 is rotated, the rotation of the input shaft 21 is accelerated by the planet gear mechanism 17a and the gear speed-up mechanism 17b and the accelerated rotation is outputted from the output shaft 37.
An oil pan 41 is provided to cover the lower portion of the second spur gear 33. This oil pan 41 functions to hold the lubricant of an appropriate amount below the second spur gear 33 and to thereby reduce the agitation loss of the lubricant in the rotation of the second spur gear 33.
A space is provided inside the housing 19 below the oil pan 41, and this space functions as a tank portion 19a that accumulates therein the lubricant (also see
In the structure of the gear box 17 shown in
Although the configuration is shown in which the oil pan 41 provided below the second spur gear 33 of the gear box 17 also functions as the baffle plate controlling the convection of the lubricant, the configuration of using the oil pan provided below the gear as the baffle plate is applicable to other gear mechanisms. Alternatively, the baffle plate controlling the convection of the lubricant may be provided separately from the oil pan 41.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2010/051769 | 2/8/2010 | WO | 00 | 7/20/2010 |