A propeller pitch varying mechanism

Abstract

The application provides a propeller variable pitch mechanism, which comprises a hub and a plurality of propellers, the hub is provided with evenly distributed blade root mounting holes on the side surface, the inner end of the propeller is rotatably mounted in the blade root mounting hole, a cylindrical cam is rotatably mounted in the hub, the cylindrical cam is internally provided with a transmission shaft extending to the upper portion of the hub, an arc-shaped groove is formed on the cylindrical cam and is obliquely arranged, a sliding block is slidably mounted in the arc-shaped groove, an axial slot is formed in the sliding block and is horizontally arranged, an eccentric pin shaft is inserted into the axial slot, and the outer end of the eccentric pin shaft is eccentrically mounted on the inner end surface of the propeller. The propeller variable pitch mechanism has simple structure, the transmission shaft drives the cylindrical cam to rotate, the sliding block slides in the inclined arc-shaped groove, axial movement is not needed, the force transmission path is simple, the circumferential movement of the sliding block can be realized through axial rotation movement, the pitch of the propeller blade is changed, the existing technical scheme using a hydraulic cylinder or an electric motor is effectively replaced, the volume and weight are small, and the working performance is stable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aviation aircraft power scheme design, and particularly relates to a propeller variable pitch mechanism. BACKGROUND

[0002] The propeller variable pitch mechanism is an executing mechanism of the propeller variable pitch system, which can transmit power to the blade root, so that the propeller blade can change the pitch angle within the allowable range around the shaft, ensure that the propeller hub and the related parts such as the control assembly do not interfere with each other within the entire variable pitch range, ensure a certain variable pitch speed and variable pitch range, and make the aircraft have high efficiency in different flight states, thereby saving energy and improving the overall function of the aircraft.

[0003] At present, the most commonly used device of the propeller variable pitch mechanism is a variable pitch mechanism driven by a hydraulic cylinder and a variable pitch mechanism driven by a motor, wherein the variable pitch mechanism driven by the motor usually adopts a mode that the motor rotates to drive the screw nut to move, and then the variable pitch slider is used to realize the rotation of the propeller blade. However, the transmission path is relatively complex, and the axial movement of the variable pitch slider needs a relatively large space, which increases the volume and weight of the hub. SUMMARY

[0004] The purpose of the present application is to provide a propeller variable pitch mechanism which replaces the existing variable pitch mechanism, can effectively save space and reduce the weight of the propeller.

[0005] The present application provides a propeller variable pitch mechanism, which comprises a hub and a plurality of propellers. The hub is provided with evenly distributed blade root mounting holes on the side surface. The inner end of the propeller is rotatably mounted in the blade root mounting hole. A cylindrical cam is rotatably mounted in the hub. A transmission shaft is mounted in the cylindrical cam and extends above the hub. An arc-shaped groove is formed on the cylindrical cam in an inclined manner. A sliding block is slidably mounted in the arc-shaped groove. An axial slot is formed on the sliding block in a horizontal manner. An eccentric pin shaft is inserted into the axial slot. The outer end of the eccentric pin shaft is eccentrically mounted on the inner end surface of the propeller.

[0006] Further, a first key groove and a second key groove are formed on the transmission shaft. The transmission shaft is connected to the shaft coupling above the hub through the first key groove and the flat key.

[0007] Further, a third key groove corresponding to the second key groove is formed on the inner wall of the cylindrical cam. The transmission shaft is connected to the cylindrical cam by embedding the flat key into the second key groove and the third key groove.

[0008] Further, a first mounting hole is formed on the top surface of the hub. A bearing fixing ring is mounted at the middle position of the first mounting hole. A first bearing is mounted at the middle position of the bearing fixing ring.

[0009] Further, the inner wall of the first mounting hole is provided with internal threads, and the outer wall of the bearing fixing ring is provided with external threads, and the first mounting hole and the bearing fixing ring are threadedly connected.

[0010] Further, a second mounting hole is formed in the bottom surface of the hub, and a second bearing is mounted at the middle position of the second mounting hole.

[0011] Further, the inner rings of the first bearing and the second bearing are sleeved on the outer wall of the transmission shaft.

[0012] Further, an end cover detachably connected with the top surface of the hub is arranged above the bearing fixing ring, a circular hole is formed at the middle position of the end cover, and the transmission shaft extends through the circular hole to the outside of the hub.

[0013] Further, a threaded hole is formed in the top surface of the hub outside the edge of the first mounting hole, a through hole corresponding to the threaded hole is arranged on the end cover, and the threaded hole and the through hole are connected through a threaded connecting piece.

[0014] Further, a sealing ring is mounted on the circular hole.

[0015] The present application has the advantages of simple structure, convenient installation, rotation of the cylindrical cam driven by the transmission shaft, sliding of the sliding block in the inclined arc-shaped groove, simple force transmission path, circumferential movement of the sliding block through only axial rotation, variable pitch of the propeller, replacement of the existing technical solutions using hydraulic cylinders or electricity, small size and weight, extremely low failure rate, extremely high control accuracy, and very stable working performance, and can be widely applied to propeller variable pitch mechanisms. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0017] Figure 1 is a structural schematic diagram of the present application;

[0018] Figure 2 is a structural schematic diagram of the transmission shaft of the present application;

[0019] Figure 3 is a structural schematic diagram of the cylindrical cam of the present application;

[0020] Figure 4 is a structural schematic diagram of the sliding block of the present application;

[0021] Figure 5 Fig. 1 is a schematic view of a paddle hub structure of the present application;

[0022] Figure 6 Fig. 2 is a schematic view of a bearing end cover structure of the present application;

[0023] Figure 7 Fig. 3 is a schematic view of a bearing fixing ring structure of the present application;

[0024] BRIEF DESCRIPTION OF DRAWINGS

[0025] In the figure: 1 - transmission shaft, 11 - first keyway, 12 - second keyway, 2 - cylindrical cam, 21 - arc-shaped groove, 3 - eccentric pin shaft, 4 - paddle hub, 41 - first mounting hole, 42 - threaded hole, 43 - second mounting hole, 5 - slider, 51 - shaft slot, 6 - end cover, 61 - sealing ring, 62 - through hole, 7 - bearing fixing ring, 71 - bearing mounting hole, 72 - external thread; DETAILED DESCRIPTION

[0026] The technical solutions of the present application will be described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0027] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0028] Furthermore, the terms "first", "second", "third", etc. are used herein for descriptive purposes only and should not be construed as indicating or implying relative importance or an ordered sequence. Thus, features defined with "first", "second" or "third" can include one or more of the features. In the description of the application, the meaning of "a plurality" is two or more, unless explicitly specified otherwise. Furthermore, the terms "mounting", "connected", "connecting" should be interpreted broadly, for example, can be fixed connection, can also be detachable connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0029] Embodiment 1

[0030] As shown in Figures 1-7 :

[0031] A propeller variable pitch mechanism, comprising a hub 4 and three propellers, the hub 4 is provided with three evenly distributed propeller root mounting holes on the side surface, and the inner end of the propeller is rotatably mounted in the propeller root mounting hole.

[0032] The hub 4 is rotatably mounted with a cylindrical cam 2, the cylindrical cam 2 is internally mounted with a transmission shaft 1 extending above the hub 4, the cylindrical cam 2 is provided with an inclined arc-shaped groove 21, the sliding block 5 is slidably mounted in the arc-shaped groove 21, the sliding block 5 is provided with a horizontally arranged shaft groove 51, and the eccentric pin shaft 3 is inserted into the shaft groove 51, and the outer end of the eccentric pin shaft 3 is eccentrically mounted on the inner end surface of the propeller.

[0033] The number of propellers in the device must be consistent with the number of propeller root mounting holes, and the propeller root mounting holes must be evenly distributed at the same height. The number of sliding blocks 5 and eccentric pin shafts 3 is also consistent with the number of propellers.

[0034] As shown in Figure 1 and Figure 2 , the transmission shaft 1 is provided with a first key groove 11 and a second key groove 12, the transmission shaft 1 is connected with the shaft coupling above the hub 4 through the first key groove 11 and the flat key, and the transmission shaft 1 is connected with the driving device such as motor through the shaft coupling.

[0035] The use basis of the flat key and the key groove is that the shaft coupling is provided with a flat key groove matched with the flat key on the inner wall surface close to the flat key, which will not be described in detail here.

[0036] As shown in Figures 1-4 , the inner wall of the cylindrical cam 2 is provided with a third key groove corresponding to the second key groove 12, and the transmission shaft 1 is connected with the cylindrical cam 2 by embedding the flat key into the second key groove 12 and the third key groove.

[0037] The outer surface of the slider 5 is provided with an axial groove 51, the slider 5 makes an inclined up and down sliding movement in the arc-shaped groove 21 on the cylindrical cam 2, and the eccentric pin shaft 3 can move left and right in the axial groove 51, avoiding movement interference, and realizing the change of the pitch angle.

[0038] As shown in Figure 1 and Figures 5-7 The top surface of the hub 4 is provided with a first mounting hole 41, a bearing fixing ring 7 is mounted at the middle position of the first mounting hole 41, a bearing mounting hole 71 is provided at the middle position of the bearing fixing ring 7, and a first bearing is mounted in the bearing mounting hole 71.

[0039] The inner wall of the first mounting hole 41 is provided with an internal thread, the outer wall of the bearing fixing ring 7 is provided with an external thread 72, and the first mounting hole 41 and the bearing fixing ring 7 are screw-connected.

[0040] A sleeve is further sleeved on the transmission shaft 1, the sleeve is mounted between the cylindrical cam 2 and the first bearing, the sleeve plays a role of axial positioning, and limits the cylindrical cam 2 to only perform axial rotation movement.

[0041] The bottom surface of the hub 4 is provided with a second mounting hole 43, a second bearing is mounted at the middle position of the second mounting hole 43, and a guide sleeve is arranged between the second bearing and the bottom surface of the cylindrical cam 2, limiting the axial movement of the second bearing and the cylindrical cam 2.

[0042] The inner rings of the first bearing and the second bearing are both sleeved on the outer wall of the transmission shaft 1 and fixedly connected with the outer wall of the transmission shaft 1.

[0043] The first bearing and the second bearing in the embodiment are both deep groove ball bearings, and the first bearing and the second bearing are smeared with lubricating grease; the effect of setting the lubricating grease is to reduce the friction of the bearing during movement, and to improve the service life and precision of the variable pitch device.

[0044] An end cover 6 detachably connected with the top surface of the hub 4 is arranged above the bearing fixing ring 7, a circular hole is provided at the middle position of the end cover 6, the transmission shaft 1 extends to the outside of the hub 4 through the circular hole, and a sealing ring 61 is mounted on the circular hole.

[0045] The top surface of the hub 4 is provided with 12 threaded holes 42 located outside the edge of the first mounting hole 41, the end cover 6 is provided with 12 through holes 62 corresponding to the threaded holes 42, and the threaded holes 42 and the through holes 62 are connected through screws.

[0046] The working process of the present application is that the transmission shaft 1 connected with the driving device rotates, the cylindrical cam 2 connected with the transmission shaft 1 rotates with it, and the rotation angle of the two is ensured to be between 0-120 degrees; the cylindrical cam 2 rotates, the slider 5 in the arc-shaped groove 21 slides, the eccentric pin shaft 3 on the slider 5 drives the propeller to rotate with the center axis of the propeller root mounting hole as the rotation axis, and the rotation of the propeller realizes the change of the pitch angle.

[0047] The present application has the advantages of simple structure, convenient installation, driving the cylindrical cam to rotate through the transmission shaft, then making the slider slide in the inclined arc-shaped groove, not needing axial movement, simple force transmission path, realizing the circular movement of the slider through only the axial rotation movement, thereby realizing the variable pitch of the blade, effectively replacing the prior art solution of using hydraulic cylinders or electricity, small volume and weight, very low failure rate, very high control precision, very stable working performance, and can be widely applied to the propeller variable pitch mechanism; the first bearing and the second bearing are smeared with lubricating grease, which can reduce the friction of the bearings during movement and improve the service life and precision of the variable pitch device; the sleeve and the guide sleeve ensure only the rotation with the axis as the rotation axis.

[0048] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A propeller pitch mechanism, characterized by: The utility model provides a propeller pitch adjustment device, including hub and a plurality of propeller, the hub side is provided with the propeller root mounting hole that evenly distributes, the inside rotation of propeller is installed in propeller root mounting hole, the inside rotation of hub is provided with cylindrical cam, the inside of cylindrical cam is provided with the transmission shaft that extends to the hub top, the arc groove that is arranged obliquely is provided on the cylindrical cam, the sliding block is slidably installed in the arc groove, the shaft slot that is arranged horizontally is provided on the sliding block, the eccentric pin shaft is inserted into the shaft slot, the eccentric pin shaft's outer end eccentricity is installed in the inside face of propeller, the cylindrical cam is driven around the own axis rotation through the transmission shaft, drives the sliding block only does the circumferential slip movement in the arc groove, does not need the axial movement of hub, realizes the pitch adjustment of propeller through the axial rotation of propeller base cylindrical cam, the top of hub is provided with first mounting hole, the middle position of first mounting hole is installed bearing fixing ring, the middle position of bearing fixing ring is installed first bearing, the sleeve is also sleeved on transmission shaft, and the sleeve is installed between cylindrical cam and first bearing.

2. A propeller pitch varying mechanism according to claim 1, characterized in that: The transmission shaft is connected with the shaft coupling above the hub through the first key groove and the flat key.

3. A propeller pitch varying mechanism according to claim 2, characterized in that: The third key groove corresponding to the second key groove is formed on the inner wall of the cylindrical cam, and the transmission shaft is connected with the cylindrical cam by embedding the flat key into the second key groove and the third key groove.

4. A propeller pitch varying mechanism according to claim 1, characterized in that: The inner wall of the first mounting hole is provided with internal threads, and the outer wall of the bearing fixing ring is provided with external threads.

5. A propeller pitch varying mechanism according to claim 4, characterized in that: The bottom surface of the hub is provided with a second mounting hole, and the middle position of the second mounting hole is provided with a second bearing.

6. A propeller pitch varying mechanism according to claim 5, characterized in that: The inner ring of the first bearing and the second bearing is sleeved on the outer wall of the transmission shaft.

7. A propeller pitch varying mechanism according to claim 4, wherein: The upper side of the bearing fixing ring is provided with an end cover detachably connected with the top surface of the hub, the middle position of the end cover is provided with a circular hole, and the transmission shaft extends to the outside of the hub through the circular hole.

8. A propeller pitch varying mechanism according to claim 7, characterized in that: The top surface of the hub is provided with a threaded hole outside the edge of the first mounting hole, the end cover is provided with a through hole corresponding to the threaded hole, and the threaded hole and the through hole are connected through a threaded connecting piece.

9. A propeller pitch varying mechanism according to claim 7, characterized in that: A sealing ring is installed on the circular hole.

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