JP2018113729A - Linear actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the invention which simplifies a mechanism advancing and retracting a connector and obtains a smooth and long-lasting mechanism by means of non-mechanical position detection.SOLUTION: A linear actuator according to the invention comprises a nut body (47) threaded with a longitudinal screw body (48) being rotated at a reduced speed by a motor (6) within a housing (1), a magnet (60) arranged at a circumference of the nut body (47), a housing (44A) which is retractily arranged in a case (43) within the housing (1) and has a connector (30) connected to its top, and a pair of non-contact sensors (70, 70A) arranged apart from each other at a circumference of the case (43). The linear actuator is constructed to detect a position of the nut body (47) in a non-contact manner.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a linear actuator, and more particularly to a novel improvement for improving reliability and durability by positioning a cylinder having a connector with a magnet and a non-contact sensor.

Conventionally used motor actuators of this type include, for example, the configurations of Patent Document 1 and Patent Document 2.
Although not shown in the drawings as the motor actuators of Patent Documents 1 and 2, in the configuration of Patent Document 1, a Hall element is provided in the vicinity of a disk having a plurality of magnetized portions, and the rotational position of the motor. It is the structure which detects.
Further, the actuator with the linear motion guide mechanism of Patent Document 2 has a configuration in which the length of the linear actuator can be shortened.
In the case of the commercially available linear actuator shown in FIG. 2 and FIG. 3, the first and second well-known first and second are disposed outside the driving body 80 provided in the longitudinal opening 5 at the center position of the cylindrical housing 1. A mechanical switch 10 including first and second switch portions 2 and 3 having two tongue pieces 2a and 3a is provided as described later.

In the housing 1, the driving body 80 is configured to be able to reciprocate, and the first and second switch portions 2 and 3 are arranged to protrude outward from the housing 1. Yes.
The mechanical switch 10 is fixedly provided on the upper portion 1 a of the housing 1 above a striker 7, which will be described later, provided on the driving body 80.

The first and second switch portions 2 and 3 are provided with first and second tongue pieces 2a and 3a. The tongue pieces 2a and 3a are elastic and move along the arrow A direction of the striker 7. By which one of the first and second tongue pieces 2a, 3a abuts, one of the tongue pieces 2a, 3a is pushed outward, and one of the switch portions 2, 3 is turned on. Has been.
The striker 7 is fixed to the driving body 80 by a pair of screws 8.
That is, the mechanical switch 10 shows a neutral position in the state of FIG. 3, and the driving body 80 moves linearly along the arrow A by the rotation of the ball screw 6 a formed of the rotating shaft by the driving of the motor 6. The housing 1 is configured to be able to appear and retract.
Accordingly, when the ball screw 6a is rotated by the driving of the motor 6 and the driving body 80 is retracted together with the striker 7, the striker 7 lifts the second tongue piece 3a, and the driving body 80 and the connector 30 are most retracted. Stop at the position (leftmost in FIG. 1).

  Next, when the retracted connector 30 is moved forward (rightward in FIG. 2), when the motor 6 is reversely rotated by a control unit (not shown), the driving body 80 moves forward, and the striker 7 Pushes the first tongue piece 2a upward, and the advancement is stopped by the control unit in a state where the connector 30 protrudes a considerable amount.

JP2002-257585 JP2016-41013A

Since the conventional linear actuator is configured as described above, the following problems exist.
That is, in particular, in the case of the conventional configuration shown in FIG. 2, as means for stopping the fixed position of the drive body 80 when the connector 30 is moved linearly, the first and second tongue pieces 2 a and 2 a of the mechanical switch 10 are used. 2b is a purely mechanical switch mechanism in which the striker 7 abuts to turn the switch on and off, so it is necessary to use a mechanical connection structure for generating a signal, and the reliability of the mechanical contact portion and It was extremely difficult to improve durability.

  The present invention has been made to solve the above-described problems. In particular, the positioning of a driving body having a connector is performed by a magnet and a non-contact sensor, thereby improving reliability and durability. It is an object of the present invention to provide a linear actuator that can obtain the above.

  A linear actuator according to the present invention includes at least a pair of non-contact sensors fixed to a case in a housing, a longitudinal screw body rotatably provided in the housing, and a nut screwed onto an outer periphery of the longitudinal screw body. A body, a magnet provided on the outer periphery of the nut body, a cylindrical body screwed into the nut body and having a connector, a motor provided on the inner side of the housing, and rotation of the motor by the longitudinal screw A toothed wheel train for transmitting to the body, and a connector provided at an end of the cylindrical body, the longitudinal screw body is rotated by rotation of the motor, and the rotation of the longitudinal screw body is The cylindrical body and the connector screwed into the nut body are configured to be linearly moved and pushed out of the housing, and the longitudinal screw body is formed of a ball screw. Longitudinal hollow part is formed Is formed, also, the non-contact sensor, a configuration formed of Hall elements.

Since the linear actuator according to the present invention is configured as described above, the following effects can be obtained.
That is, at least a pair of non-contact sensors fixed to a case in a housing, a longitudinal screw body rotatably provided in the housing, a nut body screwed onto an outer periphery of the longitudinal screw body, and the nut A magnet provided on the outer periphery of the body, a cylinder having a connector screwed to the nut body, a motor provided on the inner side of the cylinder, and the rotation of the motor for transmitting to the longitudinal screw body And a connector provided at an end of the cylindrical body, the longitudinal screw body is rotated by rotation of the motor, and is screwed into the nut body by rotation of the longitudinal screw body. By adopting a configuration in which the case and the connector thus moved are linearly moved and pushed out of the case, the linear movement position of the cylinder having the connector can be detected in a non-contact manner.
Moreover, the said longitudinal thread body consists of a ball screw, and the weight of a longitudinal thread body can be reduced because the longitudinal hollow part is formed in the axial center.
In addition, the non-contact sensor can be greatly improved in the reliability of non-contact detection by being composed of a Hall element.

It is sectional drawing which shows the linear actuator by this invention. It is sectional drawing which shows the conventional linear actuator. It is an expanded sectional view of the principal part of FIG.

  The linear actuator according to the present invention is to obtain improved reliability and improved durability by positioning a cylindrical body having a connector with a magnet and a non-contact sensor.

Hereinafter, preferred embodiments of a linear actuator according to the present invention will be described with reference to the drawings.
In addition, the same code | symbol is attached | subjected and demonstrated to a part the same as that of a prior art example, or an equivalent part.
In FIG. 1, what is indicated by reference numeral 1 is a housing whose overall shape is a box shape, and this housing 1 is provided with a motor 6 as a driving body.

A toothed wheel train 40 is provided in one end side 1a of the housing 1, and the rotational shaft 6a of the motor 6 is connected to the toothed wheel train 40 so that the rotation of the toothed wheel train 40 is decelerated. It is comprised so that.
On the outer surface 1b of the one end side 1a of the casing 1, a mounting body 41 for mounting the casing 1 to a device side (not shown) is integrally provided. A cylindrical case 43 is fixedly provided via the support member 42.

  Inside the case 43, a longitudinal screw body 48 configured to be rotated by the toothed wheel train 40 is rotatably provided via a pair of bearings 44 and 45. A threaded portion 48a similar to a known ball screw or ball screw is formed on the outer periphery of the longitudinal screw body 48, and at the axial center position thereof, the weight of the longitudinal screw body 48 is reduced. A longitudinal hollow portion 48b is formed.

A nut body 47 is screwed into the threaded portion 48 a of the longitudinal screw body 48, and the cylindrical body 44 </ b> A that is coaxially positioned outside the longitudinal screw body 48 is positioned in the nut body 47. The connector 30 is fixed and connected to the distal end side 44a of the cylindrical body 44A.
A linear guide 50 is provided between the outer periphery of the distal end side 44a of the cylindrical body 44A and the inner periphery of the case 43 so that the cylindrical body 44A does not rotate with the longitudinal screw body 48. In addition, it is configured to be able to reciprocate along the direction of arrow A.

  A plate-shaped magnet 60 is provided on the outer periphery of the nut body 47, and a pair of first and second non-contact sensors 70, 70 A made up of Hall elements and the like are mutually connected on the outer periphery of the case 43. The non-contact sensors 70 and 70A are provided so as to be able to detect the position of the magnet 60 when the longitudinal screw body 48 and the connector 30 are linearly moved along the axial direction of the arrow A. It is configured.

Next, the case where the linear actuator according to the present invention is operated will be described.
1 shows a state in which the cylindrical body 44A is housed in the housing 1. In this state, when the motor 6 is driven, the rotational force of the rotating shaft 6a of the motor 6 is as follows. After being decelerated through the toothed wheel train 40, the longitudinal threaded body 48 rotates.

By the rotation of the longitudinal screw body 48, the cylindrical body 44A is fed forward in the direction of the arrow A along the arrow B, and the connector 30 reaches and is connected to a connection portion of a device (not shown).
In the above-described state, by rotating the rotating shaft 6a of the motor 6 in the direction opposite to that described above, the nut body 47 is rotated in the reverse direction, and the cylindrical body 44A and the connector 30 protrude from the housing 1. It moves toward the rear of the arrow C from the protruding state, and returns to the state of FIG. 1, that is, the original position.
Therefore, according to the linear actuator according to the present invention, it is possible to perform complete non-contact detection by a magnet and a non-contact sensor, not a mechanical switch and striker mechanical switch as in the prior art. Etc. can be removed, and a highly reliable linear actuator can be obtained.

Next, the gist of the linear actuator according to the present invention is as follows.
That is, at least a pair of non-contact sensors 70 and 70A fixed to the case 43 in the housing 1, a longitudinal screw body 48 rotatably provided in the housing 1, and an outer periphery of the longitudinal screw body 48. A nut body 47 that is screwed, a magnet 60 that is provided on the outer periphery of the nut body 47, a cylindrical body 44 </ b> A that is screwed to the nut body 47 and has a connector 30, and an inner side of the housing 1. The motor 6, a toothed wheel train 40 for transmitting the rotation of the motor 6 to the longitudinal screw body 48, and a connector 30 provided at an end of the cylindrical body 44 </ b> A. The longitudinal screw body 48 is rotated by the rotation of the cylindrical body 1, and the cylindrical body 1 and the connector 30 that are screwed into the nut body 47 are rotated by the rotation of the longitudinal screw body 48 to move outwardly of the housing 1. Extruded configuration, and the longitudinal Flip body 48 is made of a ball screw, in its axial center, a configuration elongated hollow portion 48b is formed, also, the non-contact sensor 70,70A is a structure formed of Hall elements.

  The linear actuator according to the present invention has a pair of magnets provided apart from each other on the outer periphery of a nut body that is screwed into a longitudinal screw body that is rotated by a motor, and has a connector provided at the tip of a cylindrical body provided in the nut body, Since the positions where the cylindrical body and the connector appear and disappear are detected by the magnet and the Hall element, the mechanical loss is small and the life of the apparatus can be extended.

DESCRIPTION OF SYMBOLS 1 Housing | casing 1a One end side 1b Outer surface 6 Motor 30 Connector 40 Tooth wheel row body 41 Attachment body 42 Support member 43 Case 44a Tip side 44A Cylindrical body 44,45 Bearing 47 Nut body 48 Longitudinal screw body 48a Screw part 48b Longitudinal hollow Part 50 Linear guide 60 Magnet 70 First non-contact sensor 70A Second non-contact sensor A Axial direction B Front C Rear

Claims (3)

At least a pair of non-contact sensors (70, 70A) fixed to the case (43) in the housing (1), and a longitudinal screw body (48) rotatably provided in the housing (1), A nut body (47) screwed to the outer periphery of the longitudinal screw body (48), a magnet (60) provided on the outer periphery of the nut body (47), and a screw body connected to the nut body (47) A cylinder (44A) having a child (30), a motor (6) provided inside the cylinder (44A), and the rotation of the motor (6) to transmit the rotation of the motor (6) to the longitudinal screw body (48). Tooth wheel train (40), and a connector (30) provided at the end of the cylinder (44A),
The casing (1) and the connector (4) screwed into the nut body (47) by rotation of the longitudinal screw body (48) by rotating the longitudinal screw body (48) by rotation of the motor (6). A linear actuator characterized in that 30) is linearly moved and pushed out of the casing (1).   The linear actuator according to claim 1, wherein the longitudinal screw body (48) comprises a ball screw, and a longitudinal hollow portion (48b) is formed at an axial center thereof.   The linear actuator according to claim 1 or 2, wherein the non-contact sensor (70, 70A) comprises a Hall element.

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