JPS607540Y2 - actuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an actuator for changing the tilt of a radar antenna, for example.

Generally, for example, to support a radar antenna and change its inclination, an actuator 11 is used as shown in FIG. 1, and by changing the length of this actuator, the angle θ between the antenna surface and the actuator 11 can be adjusted. This changes the angle of the antenna 12, thereby changing the inclination of the antenna 12.

Next, let us consider a case where the actuator 11 is an actuator using a ball screw as shown in FIG. 2.

The compressive force applied to the actuator 11 changes with the antenna angle, and the angle θ between the antenna surface and the actuator 11
As becomes smaller, the compressive force on the actuator 11 becomes larger.

When this compressive force becomes larger than the frictional force generated in the ball screw section 13 and the gear mechanism section 14, the antenna 12 begins to fall naturally.

Conventionally, a brake, a friction plate, a worm, etc. are used in the gear mechanism 14 to prevent the antenna 12 from falling, but in the case of a friction plate or worm, the entire stroke of the actuator 11 is On the other hand, the operating efficiency deteriorates, and there is no point in using the ball screw portion 13.

In the case of brakes, if you forget to activate the brake when manually extending or retracting the actuator 11,
This has the disadvantage that the antenna 12 falls down by itself and is damaged.

This invention was made to eliminate the above-mentioned drawbacks.
It is an object of the present invention to provide an actuator that can automatically prevent a supported body from falling by itself without reducing operating efficiency.

Embodiments of the present invention will be described below with reference to the drawings.

Figure 3 shows the actuator of the present invention, where 21 is a gear mechanism section that transmits rotational force manually or automatically;
Reference numeral 2 denotes a ball screw portion that expands and contracts by the rotational force of this gear mechanism portion 21.

This gear mechanism section 21 includes a first spur gear 24 attached to a rotating shaft 23, second and third spur gears 26 and 27 attached to an intermediate shaft 25, and the ball screw section 2.
The fourth gear 30 is attached to the fixed shaft portion 29 of the second male thread 28, and the first and second spur gears 24, 26,
The third and fourth spur gears 27.30 are in mesh with each other.

These gears and shafts are housed in a case 31, and this case 31 is rotatably attached to a shaft 35 of a bearing member 34 attached to a fixed base 33 by a rotating member 32, for example.

Further, the fixed shaft portion 29 of the male screw 28 of the ball screw portion 22
One end is pivotally supported by the case 31, the other end is pivotally supported by the rotating member 32, and the tip is bolted.

Note that the rotating shaft 23 and the intermediate shaft 25 are pivotally supported by a case 31.

On the other hand, the female thread 36 that is screwed into the male thread 28 of the ball screw portion 22 is fixed to the casing by a cylindrical member 37, and the tip end 38 of this cylindrical member 37 is attached to a bearing member attached to a supported object, for example, the antenna 12. It is rotatably attached to a shaft 40 of 39.

Furthermore, a compression coil spring 43 attached by a stopper member 42 is provided at a predetermined position described later in the hollow portion 41 of the cylindrical member 37, and the tip of this spring 43 and the tip of the male thread 28 of the ball screw come into contact. It is set up like this.

Also, a thrust bearing 4 is attached to the tip of this male screw 28.
4 are provided.

Now, when the rotating shaft 23 is rotated, the first spur gear 24, the second spur gear 26, the third spur gear 27, and the fourth spur gear 3 are rotated.
0 and the rotation is sequentially transmitted to the male thread 2 of the ball screw portion 22.
8 is rotated, the female thread 3 of the ball screw portion 22 is rotated.
For example, 6 starts to shrink to the left.

(It extends in the case of reverse rotation.) Therefore, the cylindrical member 37 integrated with this female screw 36 also moves to the left, so the antenna 12
Pull the bearing member 39 attached to the antenna 12.
The angle θ (see FIG. 1) formed with the actuator 11 becomes smaller.

As this angle θ becomes smaller, the compressive force (load) of the antenna 12 applied to the actuator 11 increases, and when it reaches a certain value, the threading friction force of the ball screw section 22 and the meshing friction of the gears of the gear mechanism section 21 increase. Overcoming the force, the rotation axis 23
Even if the actuator 11 is left alone without being rotated,
will naturally shrink.

The compression coil spring 43 is positioned and attached so that the tip of the compression coil spring 43 comes into contact with the tip of the male screw 28 of the ball screw portion 22 a little before this point of natural contraction.

This compression coil spring 43 is connected to the internal thread 3 of the ball screw portion 22.
A spring constant is selected so that the compressive force on the antenna 12 can be maintained at a constant compressive force that will not cause the antenna 12 to fall naturally.

With this configuration, when the antenna 12 starts to fall naturally, the actuator 1 of the antenna 12
1 is directly transmitted to the male thread 28 of the ball screw part 22, and only a small part of the compressive force is applied to the female thread 36 of the ball screw part 22, so that when the shaft 23 rotates naturally, Most of the compressive force is in the ball screw part 2.
It does not join the female thread 36 of No. 2.

Therefore, shrinkage of the female thread 36 of the ball screw portion 22 is suppressed, and natural fall of the antenna 12 is prevented.

In addition, when the weight of the antenna 12 is large and a large spring force is required, or when the hollow part in which the compression coil spring 43 is contracted is narrow and a predetermined large spring force is required, as shown in FIG. It is preferable to use a parallel concentric double compression coil spring in which a second spring 46 with a smaller diameter is placed inside the first spring 45.

Further, in the above embodiments, the case where an antenna is supported is explained, but it goes without saying that it can be implemented in other ways than antennas.

As explained above, according to the present invention, the compression coil spring provided in the end of the male thread of the ball screw and the hollow part on the female thread side absorbs the compressive force at the time when the antenna starts falling naturally, and By weakening the compressive force on the antenna, it is possible to provide an actuator that can maintain good operating efficiency, which is an advantage of a ball screw, and can automatically prevent the antenna from falling.

[Brief explanation of the drawing]

Figure 1 is a perspective view to explain a general actuator for changing the tilt of an antenna, Figure 2 is a sectional view of an actuator using a conventional ball screw, and Figure 3 is an embodiment of the present invention. A sectional view of the actuator, and FIG. 4 is a sectional view showing a modification of the compression coil spring of FIG. 3. 11...Actuator, 12...Antenna, 21...Gear mechanism section, 22...
・Ball screw part, 28... Male thread, 36...
... Female thread, 42 ... Compression coil spring.

Claims (1)

[Scope of utility model registration request] In an actuator having a gear mechanism section that transmits rotational force and a ball screw section that expands and contracts by rotation of the gear mechanism section and supports a supported object, a hollow section is provided on the female thread side of the ball screw section, and the hollow section A compression coil spring is disposed in the ball screw portion, and the compression coil spring and the male screw tip of the ball screw portion come into contact with each other before the ball screw portion naturally contracts due to the compressive force applied from the supported body, and this compressive force is absorbed. An actuator characterized in that it absorbs water.