JP2000097307A - No-back device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a no-back device to prevent the damage to a friction disc even when an excessive rotation drive power is generated by an operation force from the load side. SOLUTION: When rotation drive occurs to a ball screw lever 6 by an operation force from the load side, a brake force generated between a pressure receiving disc 9 formed integrally with the ball screw lever 6 and friction discs 10 and 11 joined with the pressure receiving disc 9 is blocked by a ratchet mechanism, and a moving annular body 24 rotatable around the ball screw lever 6 is arranged, and the ratchet claws 15 and 16 of the ratchet mechanism are held at the moving annular body 24. Besides, the moving annular body 24 is held at a base frame 2N through a block force regulating mechanism PC. Thus, even when an excessive back rotation drive force is generated by an operation force from the load side, the block force regulation mechanism PC is operated, the ratchet mechanism is rotated integrally with the ball screw lever 16 through a back rotation drive force, a load on the friction discs 10 and 11 is eliminated, and a damage to the friction discs 10 and 11 is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator mainly comprising a screw feed mechanism for operating a rotor blade of an aircraft, for example, and relates to a no-back device for preventing the screw feed mechanism from being reversely rotated by an action from the rotor blade side. .

[0002]

2. Description of the Related Art This type of no-back device is usually provided with a ratchet mechanism in order to prevent a reverse rotation of the screw feed mechanism due to an action from a moving blade (load) side with an actuator mainly comprising a screw feed mechanism. A system in which a feed mechanism and a ratchet mechanism cooperate is commonly used. FIGS. 5 and 6 show the structure of a conventionally used no-back mechanism. FIG. 5 does not show a rotary drive source for rotating a blade (load) side or a screw member. The main part of the back mechanism is shown in longitudinal section, while FIG. 6 shows a cross section of the no-back mechanism.

[0003] Driving of a rotor blade (load side) in an aircraft or the like requires smooth and quick driving. Therefore, an actuator using a screw feed mechanism is employed. In particular, in order to increase the operation accuracy and to use a small driving force. For this purpose, a ball screw feed mechanism is employed. That is, in FIG. 5, reference numeral 1 denotes a base fixed to a fixing portion (not shown), in which a rotation drive source portion (not shown) is housed. The base frame 2 is inserted into the opening of the base 1 and fixed with fixing screws 19. Further, a cylindrical cover 3 extends from the left opening of the base frame 2 and is fixed with fixing screws 20. The base 1, the base frame 2, and the cover 3 constitute a fixed frame body. In the case of a moving blade action actuator,
It is installed on the main wing (fixed portion) side of the aircraft, and a no-back mechanism is installed inside this. Reference numeral 5 denotes a rotary drive shaft that is rotatably driven by a right rotary drive source (not shown). Extends to the left inside. Reference numeral 6 denotes a ball screw rod whose right end is fitted and connected to the spline coupling portion 5S of the rotary drive shaft 5, and extends from the inside of the base frame 2 to the inside of the cover 3 and is connected to the bearing 4 by the bearing 4. It is held rotatably. Reference numeral 7 denotes a ball nut rod screwed to the ball screw rod 6 via a ball 8, and is engaged with a rotation preventing member (not shown). The ball nut rod 7 extends to the left, projects the cover 3, and is connected to a load side such as a moving blade.

The rotation drive shaft 5 and the ball screw rod 6 are connected by a spline connection part 5S, and are integrally formed in the rotation direction and slightly displaceable in the axial direction. Therefore, when the rotary drive shaft 5 is rotationally driven, the ball nut rod 7 linearly reciprocates in the direction of the arrow by the feed mechanism using the ball screw. At the same time, when the ball nut rod 7 is urged rightward by the acting force from the load side, the ball screw rod 6 generates a reverse rotation force (reverse torque) by the ball screw feed mechanism. This is because the resistance is extremely small in the screw feed mechanism using the ball 8.

When the screw feed mechanism is operated by the acting force from the load side and the ball screw rod 6 is rotated in the reverse direction, the load (such as the moving blades) may return to a dangerous state. . For this reason, a mechanism for preventing the reverse rotation operation due to the acting force from the load side, that is, a no-back mechanism is provided in addition to this type of actuator.
Hereinafter, the no-back mechanism will be described. 9 in the figure
Is a pressure receiving plate attached to the ball screw rod 6 in a flange shape.
The ball screw rod 6 is provided integrally in a fixed manner in both the axial direction and the rotational direction. On both sides of the pressure receiving plate 9, ratchet plates 13 and 14 are arranged via friction plates 10 and 11. As will be apparent from the following description, the two ratchet discs 13 and 14 are arranged concentrically with the ball screw rod 6 and are held on the fixed frame side so as to be rotatable about the axis thereof. Roller-shaped thrust bearings 17 and 18 are provided on both outer sides of the ratchet machines 13 and 14, respectively. On the other hand, 12 is a support shaft inserted in the hole of the base frame 2,
Left and right ratchet pawls 15 and 16 meshing with ratchet teeth of the respective ratchet boards 13 and 14 are pivotally attached to the support shaft 12 in a swingable manner.

The relationship between the left and right ratchet discs 13, 14 and the left and right ratchet pawls 15, 16 is evident in FIG. FIG. 6 shows the right ratchet board 13 and the right ratchet claw 15,
As shown in the figure, two right ratchet pawls 15 are provided at 180 ° intervals, and mesh with two of the 18 peripheral ratchet teeth. The ratchet claw 15 is provided in the recess 2 of the base frame 2.
K, which can be swung about the support shaft 12, a wrapping spring 21 is stretched between the support shaft 12 and the pins 22 and 23 on both sides, and the ratchet claw 15 is always shown in the figure. In such a manner as to mesh with the teeth of the ratchet disc 13. When the rotary drive shaft 5 is driven to rotate by a rotary drive shaft source (not shown) to operate the load, the right ratchet board 13 is driven to rotate in a direction opposite to the direction of the arrow shown in FIG. However, in this case, the ratchet pawl 15 only swings at each ratchet tooth and swings outward so as to push the right ratchet pawl 15 away, allowing the right ratchet board 13 to rotate, and allowing the ball screw rod 6 to rotate. Allows co-rotation. Then, the operation of the load is realized to achieve the intended purpose.

However, when an improper acting force is generated from the load side and the ball nut rod 7 is pushed rightward, the ball screw feed mechanism, ie, FIG.
Of the right ratchet machine 13 in the direction of the arrow. In this case, the right ratchet pawl 15 meshes with the teeth of the right ratchet disc 13 to prevent the above rotation (back rotation). In this way, a no-back function is achieved. The above is the no-back mechanism and its function.
In FIG. 6, two ratchet mechanisms using ratchet boards 13 and 14 and both ratchet claws 15 and 16 are installed on the left and right. This is a type in which the ball screw rod 6 is driven to rotate in both directions, and the ball nut rod 7 is operated not only to the left but also to the right to actuate the load in both directions. This is to prevent no back.

When a no-back action force is generated, the pressure receiving plate 9 is urged in the axial direction. This is because the ball screw rod 6 receives this urging force. When the ball screw rod 6 is rotated rightward and leftward, this urging force is in the opposite direction. Therefore, for example, if the urging force is in the right direction, the right friction plate 10 is connected to the pressure receiving plate 9 and the right ratchet plate 1.
3, when the right ratchet mechanism performs a no-back function and the urging force occurs in the left direction, the left friction plate 11 is sandwiched between the pressure receiving plate 9 and the left ratchet plate 14. When pressed, the left ratchet mechanism performs a no-back function. Therefore, the ball screw rod 6 rotates only in one direction, and in the case of a system in which the load is operated only in one direction, the ratchet mechanism only needs to be installed in one side.

[0009]

The above-mentioned no-back function is achieved by the occurrence of a braking force due to the frictional resistance between the pressure receiving plate 9 and the right or left friction plate 10 (11), and the presence of this braking force. Things. Therefore, conventionally, a braking force corresponding to the acting force from the load side is generated,
The rotation of the ball screw 6 is prevented. However, when the acting force from the load side is excessive, the braking force is correspondingly excessive. Excessive braking force means that the pressure plate 9 and the left and right friction plates 1
The connection with 0 and 11 is unreasonable and causes damage. Then, due to the repetition of such a situation, the friction disc does not function as a friction disc, and the generation of braking force is reduced. Such a situation allows for improper movement on the load side, and may cause harm. An object of the present invention is to provide a no-back device that solves such a problem.

[0010]

In order to achieve the above object, the no-back device provided by the present invention does not fix and install a ratchet mechanism, particularly a ratchet claw, on the fixed frame side. A movable member rotatable around the screw member of the screw feed mechanism is provided, and a ratchet mechanism, particularly a ratchet claw thereof is installed on the movable member,
When the reverse rotation driving force of the screw member due to the acting force from the load side is within a predetermined value, a stopping mechanism for stopping the rotation is provided. Therefore, when the acting force from the load side is excessive and the reverse rotation driving force exceeds a predetermined value, the ratchet mechanism does not function and the rotation of the screw member is allowed.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a no-back device according to the present invention. FIGS. 1 and 2 employ a ball screw feed mechanism as in the examples of FIGS.
In addition, an embodiment in which the present invention is applied to a no-back device of a type in which the ball screw rod 6 is driven to rotate in both left and right directions is shown. 5 and FIG. 6 and their functions are the same as those of FIGS. 5 and 6 and their detailed description is omitted. 1 and 2
, 2N is a base frame which is basically a base frame 2 shown in FIG.
However, it is deformed to have a large diameter in order to install the stopping force adjusting mechanism PC. The cover 3N is also a base frame 2N
The diameter of the connecting portion is increased by increasing the diameter of the connecting portion. These functions are the same as in FIG.

The feature of the present invention resides in that the stopping force adjusting mechanism PC is provided in engagement with the ratchet mechanism. That is, both ratchet pawls 15 and 16 are supported by a support shaft 25 in the same manner as in FIG. 5, but this support shaft 25 is implanted in a movable ring 24 provided separately from the base frame 2N. Therefore, the ratchet pawls 15 and 16 are held by the movable ring 24. This ratchet claw 1
5 and 16 are held in the concave portion 24K of the movable ring 24 in the same manner as in FIGS. 5 and 6, and the wrapping spring 21 is wound around the support shaft 25 and the pins 22 and 23. ing. Then, as shown in FIG. 2, the ratchet claw 15 always meshes with the teeth of the ratchet board 13 so that a no-back function can be generated.

The movable ring 24 is supported by the base frame 2N via a stopping force adjusting mechanism PC installed at 180 ° intervals. That is, the stopping ball 3 is provided on the outer periphery of the movable ring 24.
1 are formed. The stopping ball 31 is held by the ball holding disc 26,
The ball holding disc 26 is urged outward by a compression spring 27, so that the stopping ball 31 is
Has been energized. The compression spring 27 is pressed by the pressing plate 28 in the cylinder 30. The pressing force can be adjusted by the adjusting screw 29, and thus the stopping force can be adjusted arbitrarily. Therefore, when an excessive back rotational driving force (torque in the direction of the arrow in FIG. 2) is generated due to the acting force from the load side, and the driving force whose value exceeds a predetermined value acts on the ratchet board 13, the braking ball 31 Is displaced outward against the elasticity of the compression spring 27, that is, rides on the outer peripheral surface of the movable ring 24, and the ratchet machine 1
3. The entire ratchet mechanism such as the ratchet claw 15 is configured to rotate integrally with the movable ring 24.

Since the structure according to the present invention is as described above, when the load is actuated by the rotational driving of the ball screw rod 6, an acting force from the load side is generated, and when the back rotational driving force is generated, a normal large force is generated. If this is the case, the state shown in FIG. 2 is maintained by the ratchet mechanism, and the no-back function is exhibited. If the back rotation driving force is excessively larger than a predetermined value, the stopping ball 31 rides on the outer periphery of the movable ring 24 to break the stopping function, and the entire ratchet mechanism rotates (moves), so that the friction plate 10 , 11 can be prevented from being damaged.

The features of the no-back device provided by the present invention are as described above in detail, but are not limited to the above and illustrated examples, but include various modifications. For example, in the embodiment shown in FIGS.
Is a system in which the friction plate is arranged on both sides of the pressure receiving plate and the ratchet mechanism is arranged on both sides, but the present invention is also applied to a unidirectional rotating type no-back device. Is applicable. 3 and 4 schematically show an embodiment in which the present invention is applied to the one-way rotation type. FIG. 3 is a longitudinal sectional view, and FIG. 4 shows a transverse section. In both of these figures, reference numeral 36 denotes a fixed frame, and its through hole 3
The rotation drive shaft 32 is provided through 6H. Reference numeral 32P denotes a pressure receiving plate fixed to the rotary drive shaft 32. A ball screw rod 33 extends to the left of the rotation drive shaft 32, and a ball nut rod 35 is screwed through a ball 34. 3
5F is a connection part with a load (not shown). Pressure plate 32
A ratchet board 39 and a friction board 37 are interposed between P and the fixed frame 36. 38 is a thrust bearing.
When a rotational driving force is generated by the acting force from the load side,
The generation of a braking force between the friction plate 37 and the pressure receiving plate 32P is the same as in the case of FIGS.

A ratchet pawl 40 meshes with the ratchet teeth on the outer periphery of the ratchet board 39, and the operation thereof is prevented with respect to a normal back rotation driving force. Further, as shown in the drawing, a support shaft 40S that swings and supports the ratchet claw 40 rotates (moves) about the rotation drive shaft 32.
It is implanted in a possible movable ring 41. Reference numeral 42 denotes a tension spring for urging the ratchet pawl 40 to mesh with the ratchet teeth of the ratchet board 39. As is apparent from the drawing, the ratchet pawl 40 and the tension spring 42 are held by the movable ring 41. On the other hand, a stopping ball 43 is locked to the movable ring 41. This stopping ball 43
Is urged to the movable ring 41 via the pressing plate 44 by the elastic force of the compression spring 45. 46 is a stopper. The operation in the case of the one-way rotation type shown in FIGS. 3 and 4 is the same as that in FIGS. 1 and 2 described above, and is omitted. However, excessive back rotation driving force is generated due to the acting force from the load side. When
The rotation drive shaft 32 and the entire ratchet mechanism rotate simultaneously,
Damage to the friction plate 37 can be prevented. However, this stopping force is not fixed and adjustable as shown in FIGS.

Further, in the present invention, the screw feed mechanism is not limited to the ball screw type, but can be applied to a no-back mechanism using a screw feed mechanism comprising a combination of a normal screw member and a nut member. further,
The detailed configuration in the illustrated embodiment, that is, the spring mechanism for urging the ratchet pawl to always mesh with the ratchet teeth of the ratchet board, the manner of installation thereof, and the like belong to the design area, and various modifications can be realized. The invention embraces all of them. Further, the no-back device according to the present invention is not limited to being applied only to an actuator having a rotor blade of an aircraft as a load, but is applicable to a working actuator having many other loads.

[0018]

The no-back device provided by the present invention has been described in detail above. Therefore, when the back rotation driving force due to the acting force from the load side is excessive, the rotation driving shaft and the ratchet mechanism are integrated. By rotating the friction disk in such a manner, an excessive load does not act on the friction disk and damage can be prevented, and the durability of the no-back device can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration of a no-back device according to the present invention.

FIG. 2 is a cross-sectional view showing a configuration of a no-back device according to the present invention.

FIG. 3 is a view showing a modified example of the no-back device according to the present invention.

FIG. 4 is a view showing a modified example of the no-back device according to the present invention.

FIG. 5 is a longitudinal sectional view showing a configuration of a conventional no-back device.

FIG. 6 is a cross-sectional view showing a configuration of a conventional no-back device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base 2, 2N ... Base frame 3, 3N ... Cover 4 ... Bearing 5 ... Rotation drive shaft 5S ... Spline part 6 ... Ball screw rod 7 ... Ball nut rod 8 ... Ball 9 ... pressure receiving plate 10, 11 ... friction plate 12 ... support shaft 13, 14 ... ratchet plate 15, 16 ... ratchet pawl 17, 18 ... thrust bearing 19, 20 ... fixing screw 21 ... winding type Spring 22, 23 ... Pin 24 ... Movable ring 24H ... Spherical recess 24K ... Recess 25 ... Support shaft 26 ... Ball holding board 27 ... Compression spring 28 ... Pressing board 29 ... Adjusting screw 30 ... … Cylinder 31… Stopping ball 32… Rotating drive shaft 32P… Pressure receiving board 33… Ball screw rod 34… Ball 35… Ball nut rod 36… Fixed frame 37… Friction disc 38… Thrust bearing 39 ...... Ratchet board 40 ... Ratchet claw 40S... Support shaft 41... Movable ring 42... Tension spring 43... Stopping ball 44... Pressing plate 45.

Claims (1)

[Claims] 1. A screw, comprising a combination of a screw member rotatably held by a fixed frame and driven to rotate and a nut member screwed to the screw member, wherein a load is actuated by reciprocating movement of the nut member. A feed mechanism, a pressure receiving plate mounted on the screw member, and a ratchet mechanism engaged with the pressure receiving plate via a friction plate and held on the fixed frame side so as to allow only one-way rotation of the screw member. When the load is actuated via the nut member by driving the screw member to rotate, and when the rotational driving force acts on the screw member by the action force from the load side, the screw member is actuated by the ratchet mechanism. In a no-back device configured to prevent the rotational drive of the movable member, a movable member rotatable around the screw member with respect to the fixed frame is provided,
When the ratchet mechanism is installed on the movable member, and when the reverse rotation driving force of the screw member due to the acting force from the load side is within a predetermined value, a stopping mechanism for stopping the rotation of the movable member is provided. Wherein the reverse rotation driving of the screw member is allowed when the reverse rotation driving force of the screw member due to the acting force from the first member exceeds a predetermined value.