An engine pitch angle adjustment device and adjustment method

Abstract

The present invention relates to an engine pitch angle adjusting device and an adjusting method. The engine pitch angle adjusting device includes a propeller fan cowling, a pitch angle measuring device, propeller fan blades, a pitch joint adjusting device, a propeller fan mounting hub and a propeller fan input shaft. The pitch joint adjusting device includes a rocker arm, a linkage disk and a locking device. The pitch joint adjusting device of the present invention simultaneously adjusts, measures and locks the pitch angles of the whole row of propeller fan blades in the form of a linkage disk plus multiple rocker arms, which has high adjustment efficiency and reliability and is of great significance for improving the test efficiency and the consistency of the pitch angles of the whole row of propeller fan blades.

Description

Technical Field

[0001] The invention relates to the field of aviation engines, and in particular to an engine pitch angle adjustment device and an adjustment method. Background Art

[0002] The propfan engine adjusts the pitch angle of the propfan blades through the variable pitch mechanism, so that the fan blades in different working conditions work at the appropriate incoming flow angle, improve working efficiency, and reduce the fuel consumption rate of the engine. In the working state, the propfan blades are affected by centrifugal torque, aerodynamic torque and friction torque. The variable pitch mechanism needs to overcome these external loads to drive the propfan to change pitch. In the process of designing the propfan blade type, speed and pitch angle, fluid simulation analysis will be used to determine these design parameters first to achieve the required thrust, efficiency and noise indicators, but ultimately propfan performance tests are required to correct, confirm and verify.

[0003] Some large open propfan engines are tested on scaled test pieces during performance testing. Due to the small internal space of the scaled test piece, it is sometimes impossible to install a variable pitch mechanism for pitch adjustment. At this time, it is necessary to adjust the pitch of each blade, measure and confirm the pitch angle, and lock the pitch angle, which is very inefficient. In particular, modern propfans have many blades (many open propfans have more than 10 blades) and complex performance conditions. In a performance test of a propfan, dozens or hundreds of conditions are often involved, which means that a lot of time will be spent on pitch adjustment and measurement, wasting a lot of precious test resources. At the same time, the process of measuring the pitch angle and locking one by one will cause a certain dispersion of the pitch angle of the entire row of blades. Therefore, it is necessary to design a simple and reliable pitch joint adjustment mechanism that can adjust, measure and lock the pitch angle of the entire row of blades at one time, which is of great significance for improving test efficiency and the consistency of the pitch angle of the entire row of propfan blades.

[0004] When testing the propfan performance of a propfan engine, due to space limitations and other factors, there is often no variable pitch mechanism or pitch joint adjustment device inside the propfan structure, resulting in a lot of time wasted in the propfan blade pitch angle adjustment and measurement process. Therefore, for the propfan test process, it is necessary to design a device that can perform joint pitch adjustment and measurement, so as to achieve one-time adjustment and measurement of the pitch angle of the entire row of blades, shorten the test cycle and reduce the dispersion of the pitch angle. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention proposes an engine pitch angle adjustment device and adjustment method. The adjustment device and adjustment method use a linkage disk plus multiple rocker arms to perform linkage adjustment, measurement and locking of the pitch angles of a whole row of propeller blades, thereby improving the efficiency and reliability of pitch angle adjustment.

[0006] On the one hand, the present invention provides an engine pitch angle adjustment device, which includes a propeller fan cowling, a pitch angle measurement device, propeller fan blades, a pitch joint adjustment device, a propeller fan mounting hub, and a propeller fan input shaft; wherein, the propeller fan cowling can be opened to adjust the pitch angle of the propeller fan blades; the pitch angle measurement device is used to measure the pitch angle of the propeller fan blades; the propeller fan blades are installed on the propeller fan mounting hub, and the propeller fan blades are connected to the pitch joint adjustment device; the pitch joint adjustment device is radially matched with the propeller fan mounting hub and provides radial positioning support through the propeller fan mounting hub; the propeller fan mounting hub is fixedly installed with the propeller fan input shaft; wherein, the pitch joint adjustment device includes a rocker arm, a linkage disk, and a locking device; the rocker arm abuts against the inner side of the propeller fan mounting hub and is connected to the root of the propeller fan blade, and the number of the rocker arms is the same as the number of the propeller fan blades; the linkage disk overlaps with the propeller fan mounting hub and is connected to the rocker arm, and the linkage disk is sleeved on the propeller fan input shaft and is in threaded cooperation with the propeller fan input shaft. When the linkage disk rotates on the propeller fan input shaft to achieve axial movement, it can drive the rocker arm to rotate to adjust the pitch angle; the locking device is used to lock the linkage disk.

[0007] Further, the rocker arm includes a rocker arm disk and an eccentric pin; the rocker arm disk is fixed to the root of the propeller fan blade; a U-shaped groove is provided on the linkage disk, and the eccentric pin is arranged in the U-shaped groove.

[0008] Further, the locking device includes a locking screw, a locking disk, and a nut; the locking disk is installed on the propeller fan input shaft; the locking screw is arranged on the linkage disk and can lock the linkage disk by screwing the locking screw to abut against the locking disk; the nut is sleeved on the propeller fan input shaft and is in threaded cooperation with the propeller fan input shaft, and the nut can lock the linkage disk by screwing to abut against the end of the linkage disk.

[0009] Further, the propeller fan cowling includes a left part and a right part, and the left part and the right part are detachably connected.

[0010] Further, the pitch angle measurement device includes a dial mounting seat, a dial, a dial pointer, and a dial pointer mounting seat; the dial mounting seat is installed on the right part of the propeller fan cowling, the dial is fixed to the dial mounting seat, the dial pointer mounting seat is installed on the propeller fan blade, and the dial pointer is installed on the dial pointer mounting seat.

[0011] Further, the locking disc is separately provided from the propeller fan input shaft; a notch parallel to the axial direction is provided on the radial outer side of the propeller fan input shaft to form a stepped portion, the locking disc is sleeved on the propeller fan input shaft, and the locking disc abuts against the stepped portion.

[0012] Further, a plurality of locking screws are circumferentially provided.

[0013] Further, the linkage disc is in threaded fit with the propeller fan input shaft through a fine thread, and the pitch of the fine thread is 1 mm to 2 mm.

[0014] Further, the left side portion and the right side portion of the propeller fan cowling are detachably connected by bolts.

[0015] On the other hand, the present invention also proposes an engine pitch angle adjustment method, which is implemented by using the above-mentioned engine pitch angle adjustment device. The specific implementation steps of the adjustment method are as follows:

[0016] S1. Preparation work before pitch angle adjustment, including:

[0017] (1) Open the propeller fan cowling: Remove the left side portion of the propeller fan cowling;

[0018] (2) Install the pitch angle measuring device on the propeller fan test piece, specifically including:

[0019] a) Install the dial mounting seat on the right side portion of the propeller fan cowling;

[0020] b) Fix the dial on the dial mounting seat;

[0021] c) Install the dial pointer mounting seat on the corresponding propeller fan blade of the dial mounting seat, ensuring that there is no relative movement between it and the propeller fan blade;

[0022] d) Install the dial pointer on the dial pointer mounting seat, adjust the dial pointer so that it points to the current pitch angle position of the propeller fan blade and then lock it;

[0023] S2. Pitch angle adjustment, including:

[0024] (1) Loosen the nut to ensure that the nut does not contact the linkage disc during the pitch angle adjustment process;

[0025] (2) Loosen the locking screw to ensure that the locking screw does not contact the locking disc during the pitch angle adjustment process;

[0026] (3) According to the pitch angle adjustment direction, rotate the linkage disc clockwise or counterclockwise, and observe the position of the dial pointer. At the beginning, rotate at a high speed. When the dial pointer is close to the target scale, slowly rotate the linkage disc until the target pitch angle is reached;

[0027] (4) Tighten the locking screw;

[0028] (5) Tighten the nut;

[0029] S3. Preparation before restart, including:

[0030] (1) Remove the dial pointer mounting seat from the propeller fan blade and the dial pointer mounted on the dial pointer mounting seat;

[0031] (2) Remove the dial mounting seat from the right side of the propeller fan cowling and the dial mounted on the dial mounting seat;

[0032] (3) Assemble the left side of the propeller fan cowling to the right side of the propeller fan cowling and fix the two.

[0033] The present invention has the following beneficial effects: (1) By jointly adjusting, measuring and locking the whole row of propeller fan blades, the adjusting efficiency of the pitch angle is greatly improved, and at the same time, the consistency of the pitch angle can be better maintained; (2) By adjusting the pitch angle in the way of screw feed, the adjusting precision of the pitch angle is high; (3) The pitch angle is effectively locked by the locking screw and the nut to ensure the consistency of the pitch angle during the rotation process; (4) The joint adjustment device has a simple structure and a small volume, and can be applied to many occasions where pitch adjustment is required. Description of the Drawings

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained according to these drawings.

[0035] Figure 1 It is a schematic diagram of the working state of the propeller fan test piece.

[0036] Figure 2 It is a schematic diagram of the propeller fan pitch angle linkage adjustment and measurement device.

[0037] Figure 3 It is a relationship diagram between the rocker arm swing angle and the linkage disc displacement.

[0038] Figure 4 It is a schematic diagram of the pitch angle measurement device.

[0039] Figure 5 It is a flow chart of the implementation method of the propeller fan pitch angle linkage adjustment. Detailed Embodiments

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0041] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "front end", "rear end", "both ends", "one end", "the other end", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0042] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection or a movable connection, can also be a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] Please refer to Figure 1 and Figure 2 , the propeller fan test piece mainly includes a propeller fan cowl 1, a pitch angle measuring device 2, propeller fan blades 3, a pitch joint adjustment device 4, a propeller fan mounting hub 5, and a propeller fan input shaft 6. The propeller fan cowl 1 is divided into left and right parts and is connected by bolts at the dotted line A. The pitch angle measuring device 2 is only installed on a certain propeller fan blade when the machine is stopped for pitch angle adjustment. The propeller fan blades 3 are installed on the propeller fan mounting hub 5 through bearings or bushings, and at the same time are connected to the rocker arm 401 of the pitch joint adjustment device 4; the propeller fan mounting hub 5 is fixedly installed with the propeller fan input shaft 6; the pitch joint adjustment device 4 is in radial cooperation with the propeller fan mounting hub 5 and is also in cooperation with the propeller fan input shaft 6 through threads.

[0044] The left side part 101 and the right side part 102 of the propeller fan cowl are connected by bolts. After loosening the bolts, the left side part 101 of the propeller fan cowl can be opened and removed to the left to facilitate the installation of the pitch angle measuring device 2 and the adjustment of the pitch joint adjustment device 4.

[0045] See Figure 4, the pitch angle measuring device 2 includes a dial mounting base 201, a dial 202, a dial pointer 203, and a dial pointer mounting base 204; the dial mounting base 201 is mounted on the right side portion 102 of the propeller fan cowling, the dial 202 is fixed to the dial mounting base 201, the dial pointer mounting base 204 is mounted on the propeller fan blade 3, and the dial pointer 203 is mounted on the dial pointer mounting base 204.

[0046] Continue to refer to Figure 2 , the pitch joint adjustment device 4 includes a rocker arm 401, a linkage disk 402, a locking screw 403, a locking disk 404, and a nut 405. The rocker arm 401 includes a rocker arm disk and an eccentric pin. The number of rocker arms is the same as the number of propeller fan blades. The rocker arm 401 is fixed to the bottom of the propeller fan blade root. At the same time, the eccentric pin of the rocker arm 401 is engaged with the U-shaped groove of the linkage disk 402. In order to improve the consistency of pitch angle adjustment and improve the machining and fitting accuracy of the eccentric pin and the U-shaped groove. The linkage disk 402 is lapped with the propeller fan mounting hub 5 and provides radial positioning support through the propeller fan mounting hub 5. And the linkage disk 402 is sleeved on the propeller fan input shaft 6 and is in threaded cooperation with the propeller fan input shaft 6. In this embodiment, the linkage disk 402 is engaged with the propeller fan input shaft 6 through a fine pitch thread. Optionally, the pitch of the fine pitch thread is 1 mm to 2 mm to improve the adjustment accuracy.

[0047] The locking disk 404 is mounted on the propeller fan input shaft 6. For the convenience of installation, a notch parallel to the axial direction is provided on the radial outer side of the propeller fan input shaft 6 to form a stepped portion. The locking disk 404 is sleeved on the propeller fan input shaft 6, and its right side abuts against the left side of the stepped portion of the propeller fan input shaft 6. The locking disk 404 and the propeller fan input shaft 6 are separately provided because when initially assembling the test piece, the propeller fan input shaft 6 needs to be installed into the propeller fan mounting hub 5 from right to left. By making the locking disk 404 and the propeller fan input shaft 6 into separate parts, it is convenient for the installation of the two.

[0048] When the linkage disk 402 rotates around the axial direction (X direction), the linkage disk 402 will move axially on the propeller fan input shaft 6, thereby driving the eccentric pin of the rocker arm 401 to rotate around the center of the propeller fan blade 3 root, thereby changing the pitch angle of the propeller fan. At the same time, since a fine pitch thread is used for transmission and the pitch is very small, the pitch angle can be finely adjusted.

[0049] Let the length of the rocker arm be L (the length of the rocker arm is the distance from the center of the eccentric pin to the rotation center of the propeller fan blade root), the pitch be P, and the pitch angle adjustment range be α , the pitch angle adjustment range is α The corresponding rotation angle of the linkage disk 402 is θ , then according to Figure 3 There is:

[0050] ;

[0051] ;

[0052] The rotation angle of the linkage disk 402 is three-valued The average change angle of the corresponding pitch angle is , then:

[0053] .

[0054] Assume that the nominal diameter of the thread is 60 mm, the pitch P = 1.5 mm, the length of the rocker arm L = 15 mm, and the pitch angle adjustment range is 100°. Then when the linkage disk 402 rotates the pitch angle changes by = 0.18°. It can be seen that very fine adjustment of the pitch angle can be achieved through the rotational feed of the thread.

[0055] Continue to refer to Figure 2 , the locking screw 403 is arranged on the linkage disk 402 and can lock the linkage disk 402 by screwing the locking screw 403 to abut against the locking disk 404. When the locking screw 403 is loosened and does not contact the locking disk 404, the linkage disk 402 can be easily screwed in or out. When the locking screw 403 is tightened and contacts the locking disk 404, the linkage disk 402 is locked. Exemplarily, a plurality of locking screws 403 are arranged circumferentially, for example, 4, and have a function of preventing loosening.

[0056] The nut 405 is arranged at the end of the linkage disk 402 to fix the linkage disk on the propeller fan input shaft 6. Exemplarily, the nut 405 is sleeved on the propeller fan input shaft 6 and is in threaded cooperation with the propeller fan input shaft 6, and the nut 405 can lock the linkage disk 402 by screwing to abut against the end of the linkage disk 402.

[0057] After the pitch angle is adjusted in place according to the pitch angle measuring device, the originally loosened locking screw 403 is tightened onto the locking disk 404, and finally the nut 405 is tightened, so that the pitch angle can be locked in the current position. Through the double locking of the locking screw 403 and the nut 405, when the entire test piece rotates, the linkage disk 402 will not move axially back and forth, and the pitch angle of the propeller fan blades will remain unchanged during the operation of the engine.

[0058] The pitch angle adjustment structure of the propeller fan has the following characteristics:

[0059] (1) Through the cooperation of the linkage disk and the rocker arm, the simultaneous linkage adjustment of multiple propeller fan blades is realized, improving the efficiency of pitch angle adjustment and being beneficial to ensuring the consistency of the pitch angles of the whole row of blades;

[0060] (2) The linkage disk adjusts the pitch angle through fine-pitch thread cooperation, and can finely adjust the pitch angle;

[0061] (3) The locking screw cooperates with the nut to achieve double locking of the thread, which can effectively ensure that the pitch angle remains unchanged during the rotation process;

[0062] (4) The pitch angle measuring device can measure the pitch angle without disassembling the propeller fan blades.

[0063] In view of the pitch angle adjustment and measurement requirements of the propeller fan blades, the present invention combines Figure 5 and provides a pitch angle adjustment method during the propeller fan performance test, and the specific steps are as follows:

[0064] S1. Preparation before pitch angle adjustment

[0065] (1) Open the propeller fan cap 1. Loosen the bolt between the left part 101 and the right part 102 of the propeller fan cap 1, and remove the left part 101 of the propeller fan cap to the left;

[0066] (2) Install the pitch angle measuring device 2 on the propeller fan test piece;

[0067] a) Install the dial mounting seat 201 on the right part 102 of the propeller fan cap;

[0068] b) Fix the dial 202 on the dial mounting seat 201;

[0069] c) Install the dial pointer mounting seat 204 on the corresponding propeller fan blade 3 of the dial mounting seat 201, ensuring that there is no relative movement between it and the propeller fan blade 3;

[0070] d) Install the dial pointer 203 on the dial pointer mounting seat 204, adjust the dial pointer 203 so that it points to the current pitch angle position of the propeller fan blade and then lock it.

[0071] S2. Pitch angle adjustment

[0072] (1) Loosen the nut 405 to ensure that the nut 405 does not contact the linkage disk 402 during the pitch angle adjustment process;

[0073] (2) Loosen the locking screw 403 to ensure that the locking screw 403 does not contact the locking disk 404 during the pitch angle adjustment process;

[0074] (3) According to the pitch angle adjustment direction, rotate the linkage disk 402 clockwise or counterclockwise, and observe the position of the dial pointer 203; at the beginning, rotate at a high speed, and when the dial pointer is close to the target scale, slowly rotate the linkage disk 402 until the target pitch angle is reached;

[0075] (4) Tighten the locking screw 403;

[0076] (5) Tighten the nut 405.

[0077] S3. Preparation before restart

[0078] (1) Remove the dial pointer mounting seat 204 and the upper dial pointer 203 from the propeller fan blade 3;

[0079] (2) Remove the dial mounting seat 201 and the upper dial 202 from the right side portion 102 of the propeller fan cowling;

[0080] (3) Assemble the left side portion 101 of the propeller fan cowling to the right side portion 102 of the propeller fan cowling and fasten them by bolts.

[0081] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed claims.

Claims

1. An engine pitch angle adjustment device, characterized in that: It includes a propeller fan cap, a pitch angle measuring device, a propeller fan blade, a pitch joint adjusting device, a propeller fan mounting hub and a propeller fan input shaft; Wherein, the propeller fan cap can be opened to adjust the pitch angle of the propeller fan blades; The pitch angle measuring device is used to measure the pitch angle of the propeller fan blade; The propeller fan blades are mounted on the propeller fan mounting hub, and the propeller fan blades are connected to the pitch joint adjustment device; the pitch joint adjustment device is radially matched with the propeller fan mounting hub, and radial positioning support is provided by the propeller fan mounting hub; the propeller fan mounting hub is fixedly mounted to the propeller fan input shaft; Wherein, the pitch joint adjustment device includes a rocker arm, a linkage disk and a locking device; the rocker arm abuts against the inner side of the propeller fan mounting hub and is connected to the root of the propeller fan blade, and the number of the rocker arms is consistent with the number of the propeller fan blades; the linkage disk overlaps the propeller fan mounting hub and the linkage disk is connected to the rocker arm, and the linkage disk is sleeved on the propeller fan input shaft and threadedly matched with the propeller fan input shaft, when the linkage disk rotates on the propeller fan input shaft to achieve axial movement, it can drive the rocker arm to rotate to adjust the pitch angle; the locking device is used to lock the linkage disk; wherein: The locking device comprises a locking screw, a locking plate and a nut; The locking disk is mounted on the propeller fan input shaft; the locking screw is arranged on the linkage disk and can lock the linkage disk by screwing the locking screw to abut against the locking disk; the nut is sleeved on the propeller fan input shaft and is threadedly matched with the propeller fan input shaft, and the nut can lock the linkage disk by screwing it to abut against the end of the linkage disk; The propeller fan cap includes a left side portion and a right side portion, and the left side portion and the right side portion are detachably connected; The pitch angle measuring device comprises a dial mounting seat, a dial, a dial pointer and a dial pointer mounting seat; The dial mounting seat is installed on the right side of the propeller fan cap, the dial is fixed to the dial mounting seat, the dial pointer mounting seat is installed on the propeller fan blade, and the dial pointer is installed on the dial pointer mounting seat.

2. The engine pitch angle adjustment device according to claim 1, characterized in that: The rocker arm includes a rocker arm disc and an eccentric pin, wherein the rocker arm disc is fixed to the root of the propeller fan blade; a U-shaped groove is arranged on the linkage disc, and the eccentric pin is arranged in the U-shaped groove.

3. The engine pitch angle adjustment device according to claim 1, characterized in that: The locking disk is separately arranged from the propeller fan input shaft; a notch parallel to the axial direction is arranged on the radial outer side of the propeller fan input shaft to form a step portion, the locking disk is sleeved on the propeller fan input shaft, and the locking disk abuts against the step portion.

4. The engine pitch angle adjustment device according to claim 1, characterized in that: A plurality of locking screws are arranged in the circumferential direction.

5. The engine pitch angle adjustment device according to claim 1, characterized in that: The linkage disk cooperates with the propeller fan input shaft thread through a fine thread, and the pitch of the fine thread is 1mm to 2mm.

6. The engine pitch angle adjustment device according to claim 1, characterized in that: The left side portion of the propeller fan cap and the right side portion of the propeller fan cap are detachably connected by bolts.

7. A method for adjusting an engine pitch angle, implemented by using the engine pitch angle adjustment device according to claim 1, characterized in that: The specific implementation steps of the adjustment method are as follows: S1. Preparation work before pitch angle adjustment, including: (1) Open the propeller fan cover: Remove the left side of the propeller fan cover. (2) Install the pitch angle measurement device on the propeller-fan test piece, including: a) Install the dial mounting base on the right side of the propeller fan cap; b) Fix the dial on the dial mounting base; c) Install the dial pointer mounting base to the propeller blade corresponding to the dial pointer mounting base, ensuring that there is no relative movement between the dial pointer mounting base and the propeller blade; d) Install the dial pointer on the dial pointer mounting seat, adjust the dial pointer to point to the current pitch angle position of the propeller blade, and then lock it; S2. Pitch angle adjustment, including: (1) Loosen the nut to ensure that the nut does not contact the linkage plate during pitch angle adjustment; (2) Loosen the locking screw to ensure that the locking screw does not contact the locking plate during pitch angle adjustment. (3) According to the pitch angle adjustment direction, turn the linkage dial clockwise or counterclockwise and observe the position of the dial pointer. The rotation speed should be fast at the beginning. When the dial pointer approaches the target scale, slowly turn the linkage dial until the target pitch angle is reached. (4) Tighten the locking screw; (5) Tighten the nut; S3. Preparations before restarting, including: (1) Remove the dial pointer mounting base and the dial pointer mounted on the dial pointer mounting base from the propeller blade; (2) Remove the dial mounting seat and the dial mounted on the dial mounting seat from the right side of the propeller fan cap; (3) Assemble the left side of the propeller fan cap to the right side of the propeller fan cap and secure them together.

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