JP2615764B2 - Low torque friction brake - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Field of the Invention The present invention relates to a friction brake, and more particularly, to a friction brake in which a friction material slides on a plate disk to receive a low torque braking force. .

(2) Conventional technology A conventional friction brake presses a friction material formed of resin, asbestos, sintered metal, or the like on the surface of a rotating metal plate disk with a spring such as a disc spring or a coil spring, and presses the plate. A predetermined braking force is obtained by frictional resistance acting between the disk and the friction material.

(3) Problems to be Solved by the Invention However, in the conventional friction brake, since the surface pressure of the sliding portion is generated by a spring, in order to generate a weak surface pressure for obtaining low torque, It was necessary to use an extremely weak spring constant spring. For this reason, not only is it difficult to obtain a stable torque, but also it is difficult to finely adjust the torque.

Moreover, since the surface pressure of the sliding portion is obtained by the spring, it is difficult to maintain a constant low pressure distribution on the entire peripheral surface of the plate disk, which not only causes torque fluctuation but also causes oil, moisture, and temperature fluctuations. The friction coefficient of the sliding portion also changes due to external factors such as the above, and it is difficult to obtain a constant torque.

Further, the friction material used in the conventional friction brake has a problem that the breakout torque at the time of operation is large because the coefficient of static friction and the coefficient of dynamic friction are large.

The present invention has been made in view of the above circumstances, and not only can obtain a stable low torque that is not affected by external factors, but also can easily adjust the magnitude of the torque. The aim is to provide a possible low torque friction brake.

B. Configuration of the Invention (1) Means for Solving the Problems In order to solve the above problems, a low-torque friction brake according to the present invention is provided on both sides of a plate disk rotating around a central axis. An inner brake element made of a friction material that slides on a surface of the plate disk in the circumferential groove, with a pair of retainers having a circumferential groove facing each other;
An outer brake element made of an elastic material is attached to press the inner brake element against the plate disk, and a predetermined braking torque is generated by a frictional force acting between the plate disk and the inner brake element as the plate disk rotates around the central axis. It is characterized by obtaining.

(2) Operation The low-torque friction brake of the present invention having the above-described configuration is provided with a low-friction friction brake mounted in a circumferential groove formed in a pair of retainers by the elastic force of an outer brake element mounted in the groove. An inner brake element made of friction material is pressed against both side surfaces of the plate disk. Therefore, when the plate disk rotates around the central axis, a predetermined braking force is generated by the frictional force acting between the plate disk and the inner brake element.

(3) Example An example of a low torque friction brake according to the present invention will be described below with reference to the drawings.

FIG. 5 shows a vertical stabilizer 2 of an airplane having a rudder 1, and as is apparent from FIG. 6, which is a cross-sectional view taken along the line VI-I of FIG. A trim tab 4 for finely adjusting the angle of the rudder 1 and maintaining the directional stability of the fuselage is pivotally supported by a hinge 5 at the rear edge of the rudder 1 pivoted at the position. A rod 7, which is connected to an actuator 6 provided inside the rudder 1, is pivotally supported at the tip of a horn 8 fixed to the trim tab 4, and is connected to a trim lever (not shown) of the cockpit. 9, the rod 7 of the actuator 6
Is moved back and forth, the trim tab 4 swings around the hinge 5. Then, the rudder 1 swings around the hinge 3 in the opposite direction by the air force acting on the trim tab 4, and fine adjustment of the directional stability of the body is performed.

FIG. 1 is a sectional view of the aforementioned actuator 6, and FIG. 2 is a perspective view thereof. As is clear from these figures, the rear end of the casing 11 attached to the frame 10 via the flange 11a is closed by a cover plate 12, and the center hole 12a of the cover plate 12 and the casing 11
Both ends of a screw shaft 13 on which a male screw 13a is engraved are inserted between the center holes 11b, and are fixed to the casing 11 by nuts 14.

On the outer periphery of the screw shaft 13, an inner drum 15 is rotatably supported at both ends by needle bearings 16, 16, and its female screw 15a is screwed with the male screw 13a of the screw shaft 13. An outer drum 17 is supported on the outer periphery of the inner drum 15, and a spline 1b formed on the outer drum 17 is replaced with a spline 15b formed on the inner drum 15.
By engaging with 7a, both drums 15, 17 can rotate integrally. Furthermore, the outer drum 17
Ring-shaped stoppers 18 and 19 are fixed to both ends of the inner drum 15. By contacting the inner surfaces of the stoppers 18 and 19 with the both ends of the inner drum 15,
The relative movement in the direction of the screw shaft 13 of 5, 17 is regulated. A spiral groove 17b is formed on the outer peripheral surface of the outer drum 17, and the above-described driving wire 9b is formed in the spiral groove 17b.
Is wrapped around.

A cylindrical body 21 is rotatably supported on the outer periphery of both ends of the outer drum 17 by a pair of ball bearings 20, 20. The rear end (the right end in FIG. 1) of the body 21 extends from the upper and lower portions. A pair of projecting rod support portions 21a,
21a extends rearward from an opening 11c formed in the casing 11. Further, an outer retainer 22 and an inner retainer 23, which will be described later, are fixed to the front end of the body 21 by guide bolts 24, 24 in a state of being overlapped. Then, a step portion 21 formed inside the rear end of the body 21
By engaging b and the inner retainer 23 fixed to the front end of the body 21 with the outer surfaces of the ball bearings 20, 20, the relative movement of the body 21 and the outer drum 17 in the direction of the screw shaft 13 is restricted. 3, the guide bolt 24 is engaged with a groove 26a of a pulley 26 rotatably supported by the casing 11 with a bolt 25 so that the body 21 and the outer drum 17 can be shared. The circumference is regulated. Accordingly, when the outer drum 17 moves along the screw shaft 13 while rotating, the body 21 maintains the same posture and the screw shaft 13 is integrated with the outer drum 17.
Will move along.

FIG. 4 is an enlarged view of IV in FIG. 1, and as is apparent from FIG. 4, the stopper 18 is provided at a plurality of locations on the outer periphery of one end of the outer drum 17 via a cylindrical spacer 28.
Are fixed by screws 27, and a disk-shaped stainless steel plate disk 29 is loosely fitted to the spacer 28 with a degree of freedom in the direction of the screw shaft 13. On the other hand, the outer retainer 22 fixed to the body 21 and the inner retainer
23 is provided with circumferential grooves 22a and 23a concentric with the screw shaft 13 so as to face each other. A ring-shaped inner brake element 30 made of Teflon and an outer brake element 31 made of an O-ring made of silicone rubber are mounted in the circumferential grooves 22a and 23a. 29 sides are pinched. A shim 32 having a small thickness is mounted on the bottom of the circumferential groove 23a of the inner retainer 23, and adjusts the pressing force of the inner brake element 30 against the plate disk 29.

Returning to FIG. 1, between the two ends of the casing 11 and the body 21, a pair of bellows 33, 33 are supported by fixing members 34, 35. It is designed to prevent intrusion.

Next, the operation of one embodiment of the low torque friction brake according to the present invention having the above-described configuration will be described.

When the pilot operates a trim lever (not shown) to trim the yaw of the airplane, the wire 9 is pulled in one direction, and the outer drum 17 around which the intermediate portion of the wire 9 is wound rotates. Then, the inner drum 15 that engages with the outer drum 17 via the splines 17a and 15b is supported by the needle bearings 16 and 16 and rotates around the screw shaft 13. At this time, the female screw 15a formed on the inner circumference of the inner drum 15 is
By engaging with the external thread 13a formed on the outer circumference of
The inner drum 15 and the outer drum 17 are integrated with the screw shaft 13
It moves while rotating along. The body 21 supported on the outer drum 17 by the ball bearings 20, 20 is rotated around the screw shaft 13 by one of the guide bolts 24, 24 being restrained by the pulley 26 supported by the casing 11. Without rotating the drums 15, 17
Along with the screw axis 13. In this way,
When the body 21 moves, the aforementioned rod 7 supported by the rod support portion 21a is pushed and pulled, and the movement is transmitted to the trim tab 4 via the horn 8.

When the outer drum 17 is driven to rotate around the screw shaft 13 by the wire 9 during the steering process of the trim tab 4 as described above, the plate disk 29 supported on the end face thereof via the spacer 28 also rotates integrally. At this time, since the inner brake element 30 to which the pressing force is applied by the outer brake element 31 is in sliding contact with both side surfaces of the plate disk 29,
A low frictional force acts on the drums 15 and 17 due to the minute frictional force generated between the inner and lower brake elements 30. Therefore, when operating the trim lever, the pilot can obtain a favorable steering feeling with an appropriate load. The magnitude of this braking force depends on the hardness of the silicone rubber of the outer brake element 31 or the thickness of the shim 32 mounted in the circumferential groove 23a of the inner retainer 23, thereby changing the plate of the inner brake element 30. It can be set arbitrarily by adjusting the surface pressure on the disk 29. If the plate disk 29 is supported with a degree of freedom in the direction of its central axis, the surface pressure on both side surfaces of the plate disk 29 is made uniform, and the fluctuation of torque can be further reduced.

Although the embodiments of the low-torque friction brake according to the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the present invention described in the appended claims. It is possible to make small design changes.

For example, the use place of the low-torque friction brake is not limited to the actuator for steering an airplane, and is suitable for a case where a small braking torque is obtained in a portion having a large diameter. As an example, when the rotation of the steering wheel is transmitted to another shaft while being reduced at a large reduction ratio, if the friction brake of the present invention is attached to this handle, the transmission of the rotational force in the opposite direction from the other shaft side is performed. It can be effectively blocked.

Also, a suitable low friction material other than Teflon can be used as the material of the inner brake element, and a suitable elastic material other than silicone rubber can be used as the material of the outer brake element. Further, instead of mounting the plate disk on a member rotatably supported on the fixed shaft, it can be mounted directly on the rotating shaft.

C. Effects of the Invention According to the low-torque friction brake of the present invention described above, an outer brake element made of an elastic material is provided in a circumferential groove cut into the inner surfaces of a pair of retainers disposed on both side surfaces of a rotating plate disk. And the inner brake element made of low friction material is attached, and the inner brake element is pressed against the surface of the plate disc by the elastic force of the outer brake element, so the structure is simplified and it can be installed in a narrow space. Instead, a weak braking torque by the low friction material can be obtained in a stable state.

Further, by changing the material of the outer brake element, or by inserting a shim having an adjusted thickness into the circumferential groove of the retainer, the surface pressure of the inner brake element against the plate disk can be easily adjusted. Thereby, the magnitude of the braking force can be set arbitrarily.

[Brief description of the drawings]

FIG. 1 is a sectional view of one embodiment of a low torque friction brake according to the present invention, FIG. 2 is a perspective view of the same, FIG. 3 is II in FIG.
FIG. 4 is an enlarged view of the section IV in FIG. 1, FIG. 5 is a view showing the tail of the airplane, and FIG.
It is sectional drawing by the VI-VI line. 13 ... screw shaft, 22 ... outer retainer, 23 ... inner retainer, 22a, 23a ... circumferential groove, 29 ... plate disc, 30 ... inner brake element, 31 ... outer brake element, 32 ... Sim

Claims (1)

(57) [Claims] 1. A friction material which has a pair of retainers each having a circumferential groove concentric with the central axis on both sides of a plate disk rotating about a central axis and slidingly contacting the surface of the plate disk in the circumferential groove. And an outer brake element made of an elastic material for pressing the inner brake element against the plate disk, and acts between the plate disk and the inner brake element as the plate disk rotates around the central axis. A low-torque friction brake that obtains a predetermined braking torque by frictional force.