JP2001231241A - Linear actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the length of an output shaft by eliminating the protrusion of the output shaft toward the opposite side to an output side, and make effective use of a stroke of the output shaft. SOLUTION: This actuator 20 is provided with a driving nut member 26 disposed in a hollow shaft 25 of a rotor 24 of a motor 22, and the output shaft 27 passing through the hollow shaft 26 and having screw 27a screwed with a screw 26a of the driving nut member 26 on its outer periphery. The actuator 20 outputs rotating power generated on the rotor 24 of the motor 22 as direct- acting power from the output shaft 27 with both screws 26a, 27a screwed with each other. The output thereof is produced with the output side of the output shaft 27 on the same side as the position of the driving nut member 26, from a position next to the position the output shaft 27 is made to conduct direct- action between the position of the driving nut member 26 and the end of the opposite side of the output of the hollow shaft 25, and a guide mechanism 40 is provided which makes the output shaft 27 act directly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear actuator, and more particularly, to a side opposite to the output of the actuator (here, the side opposite to the output means the side opposite to the side on which the output shaft of the actuator outputs). The present invention relates to an apparatus that can reduce the size of an output shaft and effectively add a device having a related function by effectively using the stroke of the output shaft.

[0002]

2. Description of the Related Art Conventionally, as a linear actuator of this type, for example, a cross-sectional view of FIG.
Is shown in the side view. FIG. 4 (a) and FIG.
In (b), the linear actuator 1 includes a stator 3 constituting a motor 2 and an axial center in the stator 3.
In addition to the rotor 4 which is fixed to the hollow rotary shaft 5 and is rotatably disposed, the hollow portion of the hollow shaft 5 is a portion on the shaft center of the rotor 4 which is separated from the iron core 4a. A driving nut member 6 fixed in the enlarged hollow enlarged diameter portion 5a is inserted into the hollow shaft 5 so as to protrude outside and reciprocate, and the outer peripheral surface of the nut member 6 An output shaft 7 having a screw portion 7a screwed with the screw portion 6a is provided.

[0003] The hollow shaft 5 comprises a hollow enlarged diameter portion 5a formed on one side thereof and a rotor core 4a.
And the hollow small-diameter portion 5b on the other side is rotatably supported by bearings 10, 10 and 11 disposed on frames 8, 9 fixed to both sides of the stator 3, respectively. ing.

[0004] A bearing holding portion 9a for accommodating the bearing 11 supporting the hollow small diameter portion 5b is formed in the frame 9 on the side of the hollow small diameter portion 5b.
A cylindrical bush 12 is provided inside the outer end of the output shaft 7.
And is provided so as to support the output shaft 7 so as to be able to move linearly. The cylindrical bush 12
May have a function of preventing the screw portion 7a of the output shaft 7 from rotating. 13 is an end cap, 12a,
12a is a retaining ring for holes, and 15 is a clamp for the lead wire 14 for supplying drive power to the winding of the motor 2.

Thus, the actuator 1 is
When driving the motor 2, the two screw portions 6 a, 7 a which screw the rotating power generated in the rotor 4 into the driving nut member 6 via the hollow shaft 5.
Thus, the output shaft 7 outputs the power to the outside as linear motion power.

[0006]

By the way, the output shaft 7 of the conventional linear actuator 1 is moved relative to the rotor 4 from the side opposite to the position of the drive nut member 6 (the side opposite to the output). Outputting linear motion power. However, when a stroke is output from the output shaft 7, the output shaft 7 is moved so as not to be disengaged from the drive nut member 6 in a range where the screw engagement with the drive nut member 6 does not come off. The length of the frame 9 on the side of the hollow small-diameter portion 5b from the position of the “stroke” + “the driving nut member 6”
It needed a very long length of "distance to edge".

At the same time, in such a conventional linear actuator 1, the output shaft 7 is provided on the side opposite to the output.
However, there is a problem in that the space required for mounting is large because of the protrusion, and a device having a function such as an electromagnetic brake cannot be added to the side opposite to the output.

[0008] The present invention has been made in view of such a point,
An object of the present invention is to provide a linear actuator that solves the above-described problem, eliminates the protrusion of the output shaft to the opposite side of the output, shortens the length of the output shaft, and effectively utilizes the stroke of the output shaft. To provide.

Another object of the present invention is to provide another function (for example, rotation detection, rotation number detection) related to the rotor at the hollow shaft end on the shaft end side of the output shaft opposite to the output. And a brake, etc.).

[0010]

According to the present invention, there is provided a driving nut member disposed in a hollow shaft of a rotor of a motor, the driving nut member being inserted through the hollow shaft. An outer peripheral surface having an output shaft formed with a threaded portion to be screwed with the threaded portion of the driving nut member, wherein the two threaded portions screw together rotating power generated in the rotor of the motor; Therefore, in the actuator which outputs the linear motion power from the output shaft, the following is achieved.

The output side of the output shaft is the same side as the position of the drive nut member and is output from a position close to the position, and the output shaft is output from the position of the drive nut member. A guide mechanism is provided, which allows linear movement between the hollow shaft and the end on the side opposite to the output, and in which the output shaft linearly moves.

At the end of the hollow shaft on the side opposite to the output, an end shaft is formed extending on the center axis of the hollow shaft, and the end shaft has another function (for example, rotation detection, rotation speed). Detection and braking, etc.).

The guide mechanism is connected to the output shaft via a connecting member, and includes one or a plurality of slide guide mechanisms disposed on the outer periphery of the motor. , Linear bearing or linear bush, slidably on the linear bearing or linear bush,
A linear shaft disposed in parallel with the output shaft.

Further, the guide mechanism is provided as a detent mechanism for the output shaft, on a projecting side of the output shaft, on a center line of the output shaft.

Since the present invention is configured as described above, the length of the output shaft is shortened, and the output shaft is prevented from protruding to the side opposite to the output, so that the stroke of the output shaft can be effectively reduced. Can be used. In addition, space can be saved by changing the hollow shaft to a solid shaft in the middle or extending the hollow shaft as it is. Further, by making the hollow shaft hollow, the output shaft can be penetrated.

Further, a device having other functions related to the rotor (for example, rotation detection, rotation speed detection, brake, etc.) can be added to the output opposite side.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 show an embodiment of the linear actuator of the present invention. FIG. 1 is a longitudinal sectional view thereof, and FIG. 2 is a left side view of FIG.

In FIG. 1 and FIG. 2, a linear actuator 20 includes a stator 23 constituting a motor, for example, a stepping motor 22, and a hollow rotary shaft (hereinafter referred to as a hollow shaft) mounted on an axis in the stator 23. The hollow portion of the hollow shaft 25 is expanded at a portion on the axis away from the iron core 24a of the rotor 24, in addition to the rotor 24 fixed to the shaft 25 and rotatably disposed. A driving nut member 26 fixed in the diameter-enlarged hollow enlarged portion 25a is inserted into the hollow shaft 25 so as to protrude to the outside and reciprocate. An output shaft 27 having a screw portion 27a screwed with the screw portion 26a is formed, and a guide mechanism 40 for linearly moving the output shaft 27.

The hollow shaft 25 to which the rotor core 24a is fixed is connected to a hollow enlarged portion 25 formed on one side thereof.
a and a small-diameter hollow portion 25b on the other side are fixed to both axial sides of the stator 23 by fastening screws (not shown).
8, 29, the bearings 3 arranged on the frames 28, 29
It is rotatably supported by 0, 30 and 31. The hollow enlarged diameter portion 25a is formed by screwing a lock nut 32 onto a screw portion 25c provided on the outer peripheral surface on the end side, and forming a stepped portion 2 formed on the outer peripheral surface of the hollow enlarged diameter portion 25a.
Together with 5d, it is rotatably fixed to the inner ring side of the bearings 30, 30.

The hollow enlarged diameter portion 25a is provided with a screw portion 25e on a part of the inner peripheral surface thereof, and the driving nut member 26 is provided with a screw portion 2 provided on the outer peripheral surface thereof.
6b is a threaded portion 25e on the inner peripheral surface of the hollow enlarged diameter portion 25a.
Is screwed on. Then, the driving nut member 26
While screwing the screw portion 26a provided on the inner peripheral surface thereof with the screw portion 27a of the output shaft 27, the output shaft 27 is penetrated, and the nut member 26 is screwed into the nut member 26 by a screw (not shown). The fixed end plate 33 and the lock nut 32 are also fastened to prevent loosening.

Reference numeral 34 penetrates the output shaft 27 and is fixed to an end of the actuator 20 via an auxiliary frame 35 by a fastening screw (not shown).
This is a guide holding member in which the holding portion 34a of the guide mechanism 40 is formed on the outer peripheral portion.

On the other hand, the hollow small diameter portion 2 of the hollow shaft 25
In the frame 29 on the 5b side, the bearing 31 for supporting the end portion 25f of the small hollow portion 25b is provided.
An end shaft 36 extending in the axial direction and projecting outward from the frame 29 is inserted into the inner peripheral portion of the end portion 25f on the center axis of the hollow shaft 25 so as to close the end portion 25f. Is stuck. Then, the protruding portion 36a of the end shaft 36
In addition, it is possible to connect or connect a device 37 having other functions related to the rotor 24, for example, functions such as rotation detection, rotation speed detection and braking.

The device 37 is provided outside the frame 29 and is connected to the protrusion 36a of the end shaft 36, and has other functions related to the rotor 24.
For example, an encoder is shown.

The guide mechanism 40 is connected to a distal end of the output shaft 27 via a connecting member 41 and is fixed to an end of the actuator 20.
The sliding guide mechanism 42 includes one or more (two in the present embodiment) sliding guide mechanisms 42 formed on the outer periphery in the radial direction.

That is, the slide guide mechanism 42 is connected to both ends (180 ° apart) of the output shaft 27 via the connection member 41 connected to the output end of the output shaft 27. A linear shaft 43 disposed parallel to the axial direction of the output shaft 27 and a holding portion 34a formed on the outer periphery of the guide holding member 34, which is fixed symmetrically with respect to the output shaft 27; 43 comprises a linear bearing 44 or a linear bush slidably disposed.
The output shaft 27 is guided by the guide mechanism 40 to move linearly.

As described above, the linear actuator 20
When driving the motor 22, the rotor 2
4 is guided from the output shaft 27 by the guide mechanism 40 via the hollow shaft 25 by the two screw portions 26a and 27a screwed together in the drive nut member 26. And output to the outside as linear motion power.

In the linear actuator 20, since the driving nut member 26 is disposed near the guide holding member 34, the length of the output shaft 27 is
"Stroke" + "Thickness of drive nut member 26" +
Only "the thickness of the guide holding member 34" is sufficient.
As a result, the length of the output shaft 27 can be shortened, so that the output shaft 27 can be built in the hollow shaft 25 (in the main body of the actuator 20), and the hollow small-diameter portion 25b side (output opposite) The device 37 having the other functions can be added to the side (side).

When the device 37 having another function is added, the device 37 may be attached to the protruding portion 36a of the end shaft 36 fixed to the end portion 25f of the hollow small diameter portion 25b, or may be integrated. it can. Examples of the device 37 having the other functions related to the rotor 24 include an electromagnetic brake, an encoder, a tachogenerator, and a slit plate.

FIG. 3 is a longitudinal sectional view showing another embodiment of the linear actuator according to the present invention. The difference from FIG. 1 of the embodiment is that the guide mechanism 40 and the guide mechanism 60 are different.
In FIG. 3, the same members as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted.

In FIG. 3, the linear actuator 50
Guide mechanism 6 disposed at the output side end of the output shaft 27
The detent mechanism as 0 is provided on a guide groove 61 formed on the outer peripheral surface of the output shaft 27 and parallel to the axis of the output shaft 27, and provided on the output shaft. Groove 6
1, a linear bearing 62 or a linear bush guided by a row of rolling steel balls (not shown). The linear actuator 50 is guided from the output shaft 27 by the guide mechanism 60,
As described above, the power is output to the outside as linear motion power.

Thus, the actuator 50 is
Further downsizing can be achieved. In this case, the output shaft 27 is mechanically weakened to a load in the rotational direction and a load in the vertical direction. However, in use, a known reinforcing mechanism is added to the output shaft 27 to make up for it. Can be.

The technique of the present invention is not limited to the technique in the above-described embodiment, but may be implemented by means of other modes that perform the same function. Can be changed or added.

[0033]

As is apparent from the above description, according to the linear actuator of the present invention, the output side of the output shaft is shifted from the same position as the position of the driving nut member and from a position close to the position. The output shaft is provided with a guide mechanism that allows the output shaft to linearly move between the position of the driving nut member and the output-side end of the hollow shaft, and that linearly moves the output shaft. Therefore, the output shaft does not protrude to the opposite side of the output of the linear actuator, so that the length of the output shaft can be shortened and the stroke of the output shaft can be effectively used.

Further, according to the present invention, an end shaft is formed at the end of the hollow shaft on the side opposite to the output so as to extend on the center axis of the hollow shaft. A device having other functions (for example, rotation detection, rotation speed detection, and a brake) related to the rotor can be added to the hollow shaft end on the shaft end side. Further, the hollow shaft is formed as a solid shaft in the middle, extended to a portion corresponding to the closing portion on the center axis of the solid shaft to form an end shaft, and the rotor end is formed at the shaft end. There is an effect that a device having the above-mentioned function related to the above can be added.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a linear actuator of the present invention.

FIG. 2 is a left side view of FIG.

FIG. 3 is a longitudinal sectional view showing another embodiment of the linear actuator of the present invention.

FIG. 4 shows a conventional linear actuator;
(A) is a longitudinal sectional view, and FIG. 4 (b) is a right side view of FIG. 4 (a).

[Explanation of symbols]

 20, 50, 60 Linear actuator 22 Motor 23 Stator 24 Rotor 25 Hollow shaft 25a Hollow enlarged diameter portion 25b Hollow small diameter portion 25f End 26 Driving nut member 26a, 27a Screw portion 27 Output shaft 34 Guide holding member 34a Holding portion 36 End shaft 36a Projection 37 Device with other functions 40, 60 Guide mechanism 41 Connecting member 42 Sliding guide mechanism 43 Linear shaft 44, 62 Linear bearing 61 Guide groove

Claims (4)

[Claims] 1. A driving nut member disposed in a hollow shaft of a rotor of a motor, and a screw inserted through the hollow shaft and screwed to an outer peripheral surface thereof with a screw portion of the driving nut member. An output shaft having a portion formed therein, and an actuator that outputs rotational power generated in the rotor of the motor as linear motion power from the output shaft by the two screw portions screwed together. The output side of the shaft is on the same side as the position of the drive nut member, and is output from a position close to the position, and the output shaft is opposite to the output of the hollow shaft from the position of the drive nut member. A linear actuator characterized by being provided with a guide mechanism that enables linear movement between the output shaft and an end portion on a side of the linear shaft. 2. An end of the hollow shaft opposite to the output,
2. The linear actuator according to claim 1, wherein an end shaft is formed to extend on a center axis of the hollow shaft, and a device having another function can be coupled to the end shaft. 3. 3. The guide mechanism is connected to the output shaft via a connecting member, and includes one or a plurality of slide guide mechanisms disposed on an outer periphery of the motor. 3. A linear bearing or a linear bush, and a linear shaft slidably mounted on the linear bearing or the linear bush and parallel to the output shaft. Linear actuator. 4. The output shaft according to claim 1, wherein the guide mechanism is disposed on a center line of the output shaft on a projecting side of the output shaft as a rotation preventing mechanism for the output shaft. The linear actuator according to 1.