JP2512883Y2 - Controller for linear actuator - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a linear actuator, and more particularly to a feed screw for rotating a motor as a drive source in an undulating mechanism or an elevating mechanism of a floor of a medical or home bed. The present invention relates to a control device for controlling the linear motion of a linear actuator, which is converted into a linear motion of an operating shaft using a mechanism or the like, within a predetermined stroke.

[0002]

2. Description of the Related Art Generally, a linear actuator of this type is generally one in which the rotation of a motor is decelerated by a gear mechanism or the like, and a linear movement of an operating shaft is changed by using a feed screw mechanism. As a stroke control method for this linear actuator, a limit switch is attached to the tip of the screw part of the feed screw mechanism, and when the screw is fed to the position of the switch, the functional part of the switch fits into the cut groove provided in the screw. When the motor is turned off, the screw is stopped by stopping the rotation of the motor, and the movement of the linear actuator is controlled to a predetermined stroke.

[0003]

That is, in the conventional linear actuator control method as described above, there is no direct relation between the pitch of the screw portion of the feed screw mechanism and the motor rotation speed, and the feed screw cut by the switch is cut. Since it is decided by the position of the groove, if the stroke is different, it is necessary to provide a notch groove at a different position each time, and it is necessary to produce different parts for each stroke and keep inventory in stock. Therefore, not only productivity is very poor and inventory management is complicated, but also when changing the stroke, it is necessary to replace the actuator itself, which is a very troublesome work.

In view of the above points, the present invention is to provide a linear actuator control device which rationalizes the productivity and inventory control of linear actuators and can easily change the stroke.

[0005]

In order to achieve the above object, the present invention controls the movement of a linear actuator which converts the rotation of a motor into a linear movement through a transmission means within a predetermined stroke. As a control device of the motor, the motor is attached to the rotating shaft of the motor through a speed reducing means, and is detachably attached to the speed reducing shaft that rotates according to the rotation of the motor, and the switch is turned on in the circumferential direction around the speed reducing shaft. Section and a switch-off section, and a control plate formed by setting the circumferential angle of the switch-on section so as to correspond to the stroke of the actuator, and the switch-on section and the switch-off section of the control plate are discriminated from each other. The gist of the present invention is to include a detection unit that outputs a signal for turning the motor on and off.

[0006]

The configuration of the linear actuator control device according to the present invention is as described above. For example, the deceleration ratio of the control plate that is decelerated from the motor and rotates is such that the entire circumference angle 360 ° about the deceleration axis is A value is set so as to correspond to the required maximum stroke, and a peripheral angle portion corresponding to a desired stroke is divided into a switch-on portion and a remainder thereof is divided into a switch-off portion, out of the total peripheral angle 360 °. This allows the movement of the actuator to be controlled to any stroke within the required maximum stroke range. Then, the strokes of the actuators can be changed by preparing control plates having different peripheral angles of the switch-on portion and replacing them as needed.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the embodiments shown in the drawings.

FIG. 1 shows an embodiment of a linear actuator which employs the control device according to the present invention. In the figure, reference numeral 1 is an actuator composed of a feed screw mechanism, and 2 is an electric drive source. A motor 3 is a drive shaft connected to the motor 2 via a reduction mechanism 4 such as a gear mechanism, and the drive shaft 3 is connected to a male screw 6 of the actuator 1 via a universal shaft coupling 5. Male screw 6
Is a female screw 8 fixed in the operating shaft 7 of the actuator 1.
The male screw 6 is rotated by the rotation of the motor 2 to send out the female screw 8 to linearly move the operating shaft 7, and thus the rotation of the motor 2 is linearly moved by the actuator 1 including the feed screw mechanism. Is converted to.
Further, reference numeral 10 is a control plate detachably attached to the reduction shaft 12 connected to the drive shaft 3 via reduction gear 9 such as a gear mechanism, and reference numeral 11 is a rotation angle of the control plate 10. Is a detecting means for detecting. The actuator 1 is used, for example, in an elevating mechanism for elevating the floor portion 21 of the bed A as shown in FIG.

The rotation speed of the motor 2 is, for example, 1300.
The rotation speed of the motor 2 is reduced to about 1/30 of that by the reduction means 4 and transmitted to the drive shaft 3.
Further, the rotation of the drive shaft 3 is reduced to 1/80 by the speed reducing means 9.
It is configured to be decelerated to a certain degree and transmitted to the control plate 10, and the pitch of the male screw 6 and the female screw 8 of the actuator 1 is adjusted so that the entire circumference angle 360 ° of the control plate 10 becomes the required maximum stroke of the actuator 1. Is set. That is, the speed reduction ratio of the speed reduction means 4 and the speed reduction means 9,
The pitches of the male screw 6 and the female screw 8 are set so that the operating shaft 7 of the actuator 1 linearly moves from the start point to the end point of its maximum stroke while the control plate 10 makes one revolution.

The control plate 10 is divided into a switch-on portion and a switch-off portion in the circumferential direction about the speed reduction shaft 12 as a center, and the switch-on portion and the switch-off portion of the control plate 10 are detected by detecting means. 11 determines the rotation angle of the control plate 10 and turns on and off the motor 2 in response to a signal from the detection means 11, thereby causing the operating shaft 7 of the actuator 1 to move.
Is controlled within the range of the maximum stroke corresponding to one rotation of the control plate 10.

As the detecting means 11, a transmission type photo sensor, a reflection type photo sensor, a magnetic sensor or the like can be used. As shown in FIGS. 3 and 4, the control plate 10 using a transmissive photosensor as the detection means 11 has a notch 13 on its outer periphery to serve as a switch-on part and not to be a notch. The part 14 is a switch-off part, and the presence / absence of the protrusion 14 is detected.
The rotation angle of the control plate 10 is detected by making a distinction with a transmissive photosensor as 11, and the linear motion of the actuator 1 is controlled to a predetermined stroke by turning on and off the motor 2 according to a signal from this photosensor. It is a thing.

For example, the entire circumference angle of the control plate 10 is set so that the actuator 1 moves back and forth in a straight line within a range of 360 mm, and as shown in FIG. When the circumferential angle of the switch-on portion where the notch is formed is set to 300 ° and the circumferential angle of the protrusion 14, that is, the switch-off portion is set to 60 °, the stroke of the actuator 1 is controlled to 300 mm. Further, as shown in FIG. 5B, the circumferential angle of the switch-on portion is set to 150.
If you set the peripheral angle of the switch off part to 210 °,
The stroke of the actuator 1 can be controlled to 150 millimeters. In the above example, the outer peripheral portion of the control plate 10 is notched to form the switch-on portion,
As shown in FIG. 5C, the switch-off portion side may be cut out.

Further, as shown in FIGS. 6 and 7, when a reflection type photo sensor or a magnetic sensor is used as the detecting means 11, the peripheral portion of the control plate 10 is switched on and off with a predetermined material. It may be separated from the off part.
That is, when a reflection type photo sensor is used as the detection means 11, as shown in FIG. 8 (A), the switch-on portion is coated with light-absorbing paint such as black, or conversely, the switch-off portion is coated. By applying a light-absorbing paint, it is divided into a switch-on part and a switch-off part. With this, the rotation angle of the control plate 10 is detected by the detecting means 11 and the motor 2 is turned on and off, thereby the stroke of the actuator 1 To control. When a magnetic sensor is used as the detection means 11, the rotation angle of the control plate 10 is detected by the magnetic sensor by applying a magnetic material to the switch-off portion as shown in FIG. 8B, for example.

Further, as a decelerating means for decelerating the rotation of the motor 2 and transmitting the decelerated rotation to the drive shaft 3 and further to the decelerating shaft 12 of the control plate 10, various kinds of mechanisms can be adopted. 11 to 14 show various examples of these speed reducing means. That is, as shown in FIG. 11, the rotation of the motor 2 is the spur gear.
The drive shaft 3 is decelerated by combining 15 ...
Further, it is transmitted to the reduction shaft 12 of the control plate 10. Figure 12
Reduces the rotation of the motor 2 with a helical gear 16 and transmits it to the drive shaft 3, which is further transmitted with a spur gear 15 ...
It is transmitted to the reduction shaft 12 of. Further, in the structure shown in FIG. 13, the rotation of the motor 2 is decelerated by the planetary gears 17 and transmitted to the drive shaft 3, and the spur gears 15 ...
Is transmitted to the reduction shaft 12 of the control plate 10 after deceleration. In the structure shown in FIG. 14, the rotation of the motor 2 is decelerated and transmitted to the drive shaft 3 by the worm gear 18, and the spur gear 15 is further combined from the drive shaft 3 to the deceleration shaft 12 of the control plate. And then communicate. still,
In the figure, reference numeral 19 is a safety manual rotary shaft,
When the motor 2 fails or other troubles occur, the crank handle 20 is attached and rotated to manually actuate the actuator 1.

FIG. 15 shows an example of a wiring diagram for controlling the above-mentioned linear actuator. To explain the operation of the actuator 1 of this wiring diagram on the basis of first, press the push button PB _F of hand switch portion with the switch S _F is opened in conjunction with this, the motor M side relay R _F is actuated The switch LS _F is closed and the power source is connected to the terminals 2 and 3 of the three terminals 1, 2 and 3 of the three-phase motor M, the motor M rotates normally, and the actuator 1 is pushed forward. And, although While holding down the hand switch PB _F motor M continues rotating forward, the detection means 11 control panel 10 detects that the rotation until the switch-off unit, switch the signal from the sensing means 11 PHS _F is opened, the rotation of the motor M is stopped, and the forward movement of the actuator 1 is controlled. The switch S _R in conjunction therewith pressing the pushbutton PB _R of hand switch
Is opened, the relay R _R is actuated, the switch LS _R on the motor M side is closed, the power source is connected to the terminals 1 and 2 of the motor M, the motor M rotates in the reverse direction, and the actuator 1 moves backward. And, although while pressing the hand switch PB _F motor M continues to reverse, the detection means 11 control panel 10 detects that the rotation until the switch-off unit, the switch PHS a signal from said sensing means 11
_R , the rotation of the motor M is stopped, and the backward movement of the actuator 1 is controlled. In this way, by continuously pressing the push button of the hand switch, the motor M rotates normally or reversely, and the actuator 1 moves forward or backward, but with the rotation of the motor M, the control plate 10 rotates to the switch-off portion. Is detected by the detecting means 11, and the switch PHS _F or P is detected by the signal from the detecting means 11.
When HS _R opens, the motor M stops, and the movement of the actuator 1 is controlled within a certain stroke based on the rotation angle of the control plate 10.

[0016]

As described above, in the linear actuator control device according to the present invention, the stroke of the linear motion of the actuator within the rotation angle range of the switch-on portion provided on the control plate that rotates according to the rotation of the motor. By controlling the switch, the control plate in which the switch-on portion is set to various angles in advance is prepared, and the stroke of the actuator can be changed by replacing the control plate when necessary, as in the conventional case. Compared with the case of replacing the actuator itself, the stroke can be changed very easily, maintenance is easy, and all members other than the control plate can be standardized. It can rationalize productivity, inventory control, etc.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an embodiment of a linear actuator using a control device according to the present invention.

FIG. 2 is a simplified plan sectional view of the same main portion.

FIG. 3 is a view of the detection means and the control plate in the control device
The perspective view showing an example.

FIG. 4 is an explanatory diagram of an embodiment of a control plate.

5 (A), (B) and (C) are explanatory views of various examples of the control plate. FIG.

FIG. 6 is a perspective view of a main part showing another embodiment of the control device.

FIG. 7 is a perspective view showing a relationship between a detection unit and a control plate in the control device.

8A and 8B are explanatory views of an embodiment of a control plate in the control device in both FIGS.

9 is a simplified side sectional view of the control device shown in FIG.

FIG. 10 is a simplified side sectional view of the control device shown in FIG. 7.

FIG. 11 is a perspective view of a speed reducer using a spur gear.

FIG. 12 is a perspective view of a speed reducer using a helical gear.

FIG. 13 is a perspective view of a speed reducer using a planetary gear.

FIG. 14 is a perspective view of a speed reducer using a worm gear.

FIG. 15 is a wiring diagram showing an example of a linear actuator control device according to the present invention.

FIG. 16 is an exploded perspective view showing an example of a floor-portable bed using a linear actuator.

[Explanation of symbols]

 1 Actuator 2 Motor 3 Drive shaft 4 Reduction gear 5 Universal shaft joint 6 Male screw 7 Operating shaft 8 Female screw 9 Reduction gear 10 Control plate 11 Detecting means 12 Reduction shaft 13 Cutout 14 Projection 15 Spur gear 16 Helical gear 17 Planetary gear 18 Worm Gear 19 Manual rotation shaft 20 Crank handle

Claims (1)

(57) [Scope of utility model registration request] 1. A control device for controlling the movement of a linear actuator, which is obtained by converting the rotation of a motor into a linear movement via a transmission means, within a predetermined stroke, and a reduction device is provided on a rotation shaft of the motor. Attached to a reduction shaft that rotates in response to the rotation of the motor, and is detachably attached to the reduction shaft, and is divided into a switch-on portion and a switch-off portion in the circumferential direction around the reduction shaft. A control plate whose angle is set so as to correspond to the stroke of the actuator; and a detection means for discriminating between the switch-on part and the switch-off part of the control plate and for issuing a signal for turning the motor on and off. A control device for a linear actuator.