Variable pitch mechanism and power generator

Abstract

To provide a variable pitch mechanism which can achieve reduction of mechanical loss caused by friction etc., reduction of breakage, and reduction of costs needed for maintenance inspection and repair and restoration, and to provide a power generator.SOLUTION: A movable pitch mechanism 2 includes: a guide rail 21 having a closed curve shape; guide rollers 22 which may move along the guide rail 21; guide rods 23 each of which is disposed on a rear edge side end surface of a blade 31 and rotatably supports the guide roller 22; and guide rail position adjustment means 24 configured to allow the guide rail 21 to be arranged offset from the rotary shaft 32 and position the guide rail 21 in an offset state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a variable pitch mechanism and a power generation device, and more particularly to a variable pitch mechanism and a power generation device that can change the pitch angle of blades. [Background technology]

[0002] In recent years, with growing environmental awareness, there has been a shift away from fossil fuels, which emit carbon dioxide that causes global warming when used, to renewable energy. For example, renewable energy sources such as wind power generation, which utilizes wind energy, tidal power generation, which utilizes the energy of ocean currents, and tidal power generation, which utilizes the energy of the ebb and flow of the tides, use external forces generated by natural phenomena to rotate blades and convert the energy into electrical energy.

[0003] For example, Patent Document 1 discloses a power generating device that utilizes the kinetic energy of a water flow, and has a Voith-Schneider propeller type vertical axis water turbine that has a rotation axis perpendicular to the inflow direction of the water flow, has multiple blades that perform a pitching motion once per rotation, and the pitch angle of the blades is set by an eccentric shaft positioned perpendicular to the inflow direction of the water flow. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-4343 Summary of the Invention [Problem to be solved by the invention]

[0005] Typical turbines used in wind power generation, tidal power generation, etc. are classified into horizontal axis lift types (e.g., propeller types), vertical axis lift types (e.g., Darrieus types, gyromill types), and vertical axis drag types (e.g., Savonius types, crossflow types). It is generally known that the output efficiency of these turbines is such that horizontal axis lift types are suitable for high-speed flow regions, vertical axis lift types are suitable for medium-speed flow regions, and vertical axis drag types are suitable for low-speed flow regions.

[0006] Therefore, the type of turbine is selected based on the assumption that it will achieve the highest output efficiency throughout the year, taking into account the changes in flow velocity and flow velocity distribution at the installation location. In other words, renewable energy using these turbines does not always operate efficiently, and there will be times and periods when it is inefficient to a certain extent.

[0007] Furthermore, because natural phenomena such as wind, ocean currents, and tides constantly change direction and magnitude, it is ideal to change the direction and pitch angle of the blades (the angle of the blades relative to the blade rotation axis) to achieve maximum power generation efficiency in response to the current.

[0008] For example, Patent Document 1 proposes a variable pitch mechanism that uses a Voith-Schneider propeller system. However, the variable pitch mechanism of the Voith-Schneider propeller system requires multiple link shafts and multiple rotating shaft parts for each blade, and has many moving parts, which leads to problems such as increased mechanical loss due to friction, an increased risk of damage and breakdowns, and increased costs for maintenance, inspection, and repair and restoration.

[0009] The present invention was devised in consideration of these problems, and aims to provide a variable pitch mechanism and a power generating device that can reduce mechanical loss due to friction, etc., reduce damage and failure, and reduce the costs required for maintenance, inspection, repair, and restoration. [Means for solving the problem]

[0010] According to the present invention, there is provided a variable pitch mechanism that changes the pitch angle of a plurality of blades relative to a rotation axis that is rotated by the blades, the variable pitch mechanism comprising: a guide rail having a closed curved shape; a guide roller that is movable along the guide rail; a guide rod that is disposed on the end face on the trailing edge side of the blade and rotatably supports the guide roller; and a guide rail position adjustment means that is configured to be able to position the guide rail eccentrically relative to the rotation axis and to be able to position the eccentric state.

[0011] The guide rail position adjusting means may include a sliding mechanism with two axes that are perpendicular to each other.

[0012] The variable pitch mechanism may have a blade shaft arranged on an end surface on the leading edge side of the blade, and a blade holding member connected to the rotating shaft and rotatably holding the blade shaft, and the blade holding member may be configured so as not to interfere with the guide rod.

[0013] The radius of the guide rail may be set to a value different from the radius of the orbit of the blade main shaft.

[0014] Furthermore, according to the present invention, there is provided a power generating device comprising: a turbine equipped with a variable pitch mechanism having any of the above-described configurations; and a generator connected to the turbine. [Effects of the Invention]

[0015] According to the variable pitch mechanism and power generation device of the present invention described above, the guide rollers arranged on each blade are moved along the guide rail, so that the pitch angle of the blade can be changed simply by using the guide rail position adjustment means to maintain the guide rail in an eccentric state with respect to the rotation axis of the blade.

[0016] Therefore, compared to conventional variable pitch mechanisms such as the Voith-Schneider propeller system, the number of moving parts can be reduced, which reduces mechanical losses due to friction, damage, and costs required for maintenance, inspection, repair, and restoration. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic overall configuration diagram showing a power generating device according to an embodiment of the present invention; [Figure 2] 2A and 2B are explanatory diagrams of the variable pitch mechanism shown in FIG. 1, where FIG. 2A is an explanatory diagram of the guide rail, and FIG. 2B is an explanatory diagram of the slide mechanism. [Figure 3] FIG. 10 is an explanatory diagram showing a state in which the guide rail is eccentric in the X-axis direction. [Figure 4] FIG. 10 is an explanatory diagram showing a state in which the guide rail is eccentric in the Y-axis direction. [Figure 5] 10 is an explanatory diagram showing a state in which the guide rail is eccentric in the X-axis direction and the Y-axis direction. FIG. [Figure 6] FIG. 10 is an explanatory diagram showing a state in which the position of the guide rail is aligned with the rotation axis. [Figure 7] 1. FIG. 4 is an explanatory diagram showing a first modified example of the variable pitch mechanism shown in FIG. [Figure 8] 1. FIG. 4 is an explanatory diagram showing a second modified example of the variable pitch mechanism shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described with reference to Figs. 1 to 8. Fig. 1 is a schematic overall configuration diagram showing a power generation device according to one embodiment of the present invention. Fig. 2 is an explanatory diagram of the variable pitch mechanism shown in Fig. 1, where (A) is an explanatory diagram of the guide rail and (B) is an explanatory diagram of the slide mechanism. Fig. 3 is an explanatory diagram showing a state in which the guide rail is eccentric in the X-axis direction.

[0019] In each figure, the X-axis, Y-axis, and Z-axis represent three Cartesian coordinate systems, the plane including the X-axis and Y-axis (XY plane) forms a horizontal plane, and the Z-axis is set vertically upward.

[0020] As shown in Fig. 1, a power generating device 1 according to one embodiment of the present invention includes a turbine 3 equipped with a variable pitch mechanism 2, and a generator 4 connected to the turbine 3. Note that typical components such as a support structure for the generator 4, power cables, and a gearbox are omitted from Fig. 1.

[0021] The turbine 3 is a prime mover that obtains power by converting fluid energy into rotational motion. It is also called a windmill in the field of power generation that uses wind power, and a waterwheel in the field that uses water power (ocean current or tidal power). The turbine 3 shown in FIG. 1 is, for example, a tidal power generation turbine, and is used by being submerged in an area of ​​the ocean where tides occur. The turbine 3 is a vertical axis turbine with its rotation axis set in the Z-axis direction.

[0022] The turbine 3 is not limited to the configuration shown in the figure, and the rotation axis may be set in the X-axis direction or the Y-axis direction. The turbine 3 may also be a wind power generation turbine, an ocean current power generation turbine, or a power generation turbine that utilizes the energy of other fluids.

[0023] The turbine 3 includes, for example, three blades 31 that receive the flow of fluid, a rotating shaft 32 that is rotated by these blades 31, blade main shafts 33 that are arranged on both end surfaces on the leading edge side of each blade 31, a first blade holding member 34 that is connected to the rotating shaft 32 and rotatably holds the upper blade main shaft 33, a second blade holding member 35 that rotatably supports the lower blade main shaft 33, a first base 36 that is arranged above the blades 31, and a second base 37 that is arranged below the blades 31.

[0024] The blades 31 extend, for example, in the Z-axis direction and have an airfoil-shaped cross section in the XY plane. As shown in Fig. 3, the blades 31 are arranged so that their dorsal sides face radially outward from the rotation shaft 32 and their ventral sides face radially inward from the rotation shaft 32. In Fig. 1, the blades 31 are illustrated with a gradation of color that becomes lighter from the leading edge side to the trailing edge side. Note that in Fig. 1, the dorsal side of the central blade 31 is illustrated, and the ventral sides of the left and right blades 31 are illustrated.

[0025] The rotating shaft 32 is disposed, for example, along the Z-axis direction on the rotation center of the blade main shaft 33. An output gear 32a that transmits power to the generator 4 is disposed at the upper end of the rotating shaft 32, and a first blade holding member 34 is disposed at the lower end of the rotating shaft 32, with these components rotating integrally. A bearing 32b is disposed in the middle of the rotating shaft 32.

[0026] The blade main shaft 33 is disposed so as to extend in the Z-axis direction from the upper and lower end surfaces of the blade 31. The blade main shaft 33 is connected to a first blade holding member 34 and a second blade holding member 35 so as to be rotatable when the pitch angle of the blade 31 is changed. The upper and lower blade main shafts 33 are disposed on the same axis.

[0027] The first blade holding member 34 is a component that transmits the rotational energy of the blade 31 to the rotation shaft 32. As shown in Fig. 3, the first blade holding member 34 has a disk-shaped center portion 34a having an area large enough to fix the rotation shaft 32, and three arm portions 34b extending radially outward from the center portion 34a. The rotation shaft 32 is fixed to the center portion 34a, and the blade main shaft 33 is rotatably connected to the ends of the arm portions 34b.

[0028] As shown in the figure, first blade holding member 34 is disposed above blade 31 and below first base 36. Since variable pitch mechanism 2, which will be described later, is disposed on the side of first blade holding member 34, conditions such as the size of center portion 34a and the shape and length of arm portion 34b are designed so that first blade holding member 34 and variable pitch mechanism 2 (specifically, guide rod 23) do not interfere with each other.

[0029] The second blade holding member 35 is a component that rotatably holds the blade 31. The second blade holding member 35 is disposed below the blade 31 and is not adjacent to the variable pitch mechanism 2, so there is no need to consider interference with the variable pitch mechanism 2. Therefore, the shape of the second blade holding member 35 may be the same as that of the first blade holding member 34, or may simply be a disk shape.

[0030] The first base 36 is a flat plate-shaped component that supports the upper part of the rotating part of the turbine 3. A bearing 32b of the rotating shaft 32 is fixed to the center of the first base 36. In addition, the variable pitch mechanism 2 is disposed on the underside of the first base 36.

[0031] The second base 37 is a flat plate-shaped component that supports the lower part of the rotating part of the turbine 3. A support shaft 37a that rotatably supports the second blade holding member 35 is disposed in the center. When the turbine 3 is installed on a floating structure or the like, the first base 36 and the second base 37 are fixed to the floating structure.

[0032] The variable pitch mechanism 2 includes a guide rail 21 having a closed curved shape (e.g., a ring shape), a guide roller 22 movable along the guide rail 21, a guide rod 23 disposed on the end face on the trailing edge side of the blade 31 and rotatably supporting the guide roller 22, and a guide rail position adjustment means 24 configured to be able to position the guide rail 21 eccentrically relative to the rotation axis 32 and to be able to position the eccentric state.

[0033] In order to improve the rotational efficiency of the blades 31 in a predetermined flow velocity range, it is preferable to adjust the pitch angle (the angle of the blades relative to the blade rotation axis) of the blades 31. If an attempt is made to constantly control the pitch angle of the blades 31 to an optimal angle in a flow region where the flow velocity changes from moment to moment, the structure and control of the variable pitch mechanism will become complicated.

[0034] The present invention is based on the premise that the turbine 3 is installed in a watershed where the flow velocity changes, and allows the pitch angle to be adjusted arbitrarily in order to improve efficiency per a specified unit (day, week, month, year), for example, in the watershed where the turbine is installed.

[0035] 1 and 2(A), the guide rail 21 has a ring shape, which is a closed curved shape, and has a circular groove 21a formed on the lower surface for guiding the guide roller 22. For ease of explanation, a cross section of the guide rail 21 is shown in FIG.

[0036] The guide roller 22 is inserted into the groove 21a of the guide rail 21 and rotatably supported by the guide rod 23. The groove 21a of the guide rail 21 may have any shape as long as it allows the guide roller 22 to move smoothly.

[0037] The guide rod 23 is connected to the upper end surface of the blade 31. The variable pitch mechanism 2 changes the pitch angle of the blade 31 by moving the portion of the blade 31 on the trailing edge side of the blade main shaft 33. Therefore, the guide rod 23 is disposed on the trailing edge side of the blade main shaft 33.

[0038] The guide rail position adjustment means 24 is, for example, a sliding mechanism with two orthogonal axes (X-axis and Y-axis) as shown in FIG. 2(B). The sliding mechanism may be of a ball screw type or a linear guide type, as long as it can maintain the state in which the guide rail 21 has been moved in the X-axis or Y-axis direction. The sliding mechanism may also be of a manually driven type or an electrically driven type. Note that, for the sake of convenience, the driving means of the sliding mechanism is not shown in FIG. 2(B).

[0039] Here, the operation when the guide rail 21 is eccentric in the X-axis direction will be described with reference to Figure 3. Here, the center of rotation of the blade 31 (center of the rotation shaft 32) is denoted as Ob, the center of rotation of the guide roller 22 (center of the guide rail 21) is denoted as Og, the rotational trajectory of the blade main shaft 33 is indicated by a one-dot chain circle, and the rotational trajectory of the guide rod 23 is indicated by a two-dot chain circle.

[0040] 3, by moving guide rail 21 by Δx in the negative direction of the X axis using guide rail position adjustment means 24, center Og can be offset in the X axis direction from center Ob. In this case, the pitch angle of blade 31 becomes 0° near the timing when it crosses the Y axis, becomes smallest near the timing when it crosses the X axis in the positive region, and becomes largest near the timing when it crosses the X axis in the negative region.

[0041] Next, the operation when the guide rail 21 is eccentric in the Y-axis direction will be described with reference to Fig. 4. Fig. 4 is an explanatory diagram showing a state in which the guide rail is eccentric in the Y-axis direction. For ease of explanation, the first blade holding member 34 is not shown in Fig. 4.

[0042] 4, the center Og can be offset in the Y-axis direction from the center Ob by moving the guide rail 21 by Δy in the positive direction of the Y-axis using the guide rail position adjustment means 24. In this case, the pitch angle of the blade 31 becomes 0° near the timing when it crosses the X-axis, becomes smallest near the timing when it crosses the Y-axis in the negative region, and becomes largest near the timing when it crosses the Y-axis in the positive region.

[0043] Next, the operation when the guide rail 21 is eccentric in the X-axis direction and the Y-axis direction will be described with reference to Fig. 5. Fig. 5 is an explanatory diagram showing a state in which the guide rail is eccentric in the X-axis direction and the Y-axis direction. For ease of explanation, the first blade holding member 34 is not shown in Fig. 5.

[0044] 5, by using the guide rail position adjustment means 24 to move the guide rail 21 by Δx in the positive direction of the X axis and by Δy in the positive direction of the Y axis, the center Og can be offset from the center Ob in the X-axis and Y-axis directions. In this case, the pitch angle of the blade 31 becomes 0° near the timing of passing through the second and fourth quadrants of the XY coordinate system, becomes smallest near the timing of passing through the third quadrant, and becomes largest near the timing of passing through the first quadrant.

[0045] In this way, the pitch angle can be changed arbitrarily by changing the position of the guide rail 21 with the guide rail position adjustment means 24. Note that the movement direction and movement amount of the guide rail 21 shown in Figures 3 to 5 are merely examples.

[0046] 6, the rotation center Ob of the blade 31 (the center of the rotation shaft 32) and the rotation center Og of the guide roller 22 (the center of the guide rail 21) can also be adjusted to coincide with each other.

[0047] Next, a first modified example of the variable pitch mechanism 2 will be described with reference to Fig. 7. Here, Fig. 7 is an explanatory diagram showing a first modified example of the variable pitch mechanism shown in Fig. 1. In the modified example shown in Fig. 7, the rotational orbit radius Rg of the guide rod 23 is set larger than the rotational orbit radius Rb of the blade main shaft 33.

[0048] In this way, the magnitude of the pitch angle can also be set by setting the rotational orbit radius Rg of the guide rod 23 to a value different from the rotational orbit radius Rb of the blade main shaft 33. Although not shown, the rotational orbit radius Rg of the guide rod 23 may be set to be smaller than the rotational orbit radius Rb of the blade main shaft 33.

[0049] Next, a second modified example of the variable pitch mechanism 2 will be described with reference to Fig. 8. Here, Fig. 8 is an explanatory diagram showing a second modified example of the variable pitch mechanism shown in Fig. 1. In the second modified example shown in Fig. 8, the groove 21a of the guide rail 21 is configured to have an elliptical shape. With this configuration, the rotational trajectory of the guide rod 23 can be changed to an elliptical trajectory.

[0050] In this way, if the guide roller 22 is shaped so that it can move smoothly along the groove 21a of the guide rail 21 and the blade main shaft 31 can rotate following it, the rotational trajectory of the guide rod 23 can be set arbitrarily, and the pitch angle at each rotational position of the blade 31 can be controlled arbitrarily.

[0051] The shape of the guide rail 21 (groove 21a) is not limited to the elliptical shape shown in the drawing, and the long axis may be set in the Y-axis direction or may be set obliquely as long as the shape allows smooth movement of the guide roller 22. The shape of the guide rail 21 (groove 21a) may also be a curved shape other than an ellipse (for example, an oval shape, an elliptical shape, a shape that meanders around the circumference, etc.).

[0052] According to the variable pitch mechanism 2 and power generation plant 1 of the present embodiment described above, the guide rollers 22 arranged on each blade 31 are moved along the guide rails 21, and therefore the pitch angle of the blades 31 can be changed simply by maintaining the guide rails 21 in an eccentric state with respect to the rotation shafts 32 of the blades 31 using the guide rail position adjustment means 24.

[0053] Therefore, compared to conventional variable pitch mechanisms such as the Voith-Schneider propeller system, the number of moving parts can be reduced, which reduces mechanical losses due to friction, damage, and costs required for maintenance, inspection, repair, and restoration.

[0054] The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0055] 1. Power generating equipment 2 Variable pitch mechanism 3 Turbine 4. Generator 21 Guide rail 21a Groove 22 Guide roller 23 Guide rod 24 Guide rail position adjustment means 31 Blade 32 Rotation axis 32a output gear 32b Bearing 33 Blade shaft 34 First blade holding member 34a center 34b Arm 35 Second blade holding member 36 First Base 37 Second Base 37a Support shaft

Claims

1. A variable pitch mechanism for changing the pitch angle of a plurality of blades relative to a rotation axis rotated by the blades, A guide rail with a closed curved shape; a guide roller movable along the guide rail; a guide rod disposed on an end surface of the blade on the trailing edge side and rotatably supporting the guide roller; a guide rail position adjusting means configured to be able to eccentrically position the guide rail with respect to the rotation shaft and to position the eccentric state; A variable pitch mechanism comprising:

2. 2. The variable pitch mechanism according to claim 1, wherein said guide rail position adjusting means includes a sliding mechanism with two axes that are perpendicular to each other.

3. 2. The variable pitch mechanism according to claim 1, further comprising: a blade main shaft disposed on an end surface on a leading edge side of the blade; and a blade holding member connected to the rotary shaft and rotatably holding the blade main shaft, wherein the blade holding member is configured not to interfere with the guide rod.

4. 4. The variable pitch mechanism according to claim 3, wherein the radius of the guide rail is set to a value different from the radius of the orbit of the blade main shaft.

5. A power generating device comprising: a turbine equipped with the variable pitch mechanism according to any one of claims 1 to 4; and a generator connected to the turbine.

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