JPH05223789A - Actuator - Google Patents

Abstract

PURPOSE:To obtain an actuator from which the worn state of its gears can be easily recognized. CONSTITUTION:A worm gear is put on a shaft 1 which is rotated by means of a motor 8. A geared sleeve and stem are provided on the inside of the worm gear. The rotation of the shaft 1 is transmitted to the stem through the worm gear and sleeve. A pulse generator, overcurrent detecting member, counter 10, and number-of-pulse display 12 are incorporated in such actuator. The pulse generator is constituted of a rotary encoder 3 and the overcurrent detecting member is constituted of a current sensor 9 and pulse forming device 11. The rotary encoder 3 generates pulses of the number corresponding to the rotational amount of the shaft 1. The sensor 9 detects the overcurrent of the motor 8 and the device 11 generates trigger pulses based on the output signal of the sensor 9. Then the counter 10 counts the number of pulses received from the encoder 3. The number of pulses counted by the counter 10 is displayed on the display 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator, and more particularly to an actuator for converting the rotation amount of a drive source into another rotation amount or a linear movement amount.

[0002]

2. Description of the Related Art Conventionally, as this type, a plurality of gears are provided on a shaft that is rotated by the drive of a motor that is a drive source, so that the rotation amount of the shaft is different from that of other gears. An actuator that can be converted into a quantity is known, but in the case of such an actuator, it is easy for dust and the like to enter between the gears due to the mechanism, which causes friction between the gears. It was sometimes worn out.

The wear generated between the gears can be operated without any trouble as long as it is within a predetermined range. However, if the wear exceeds the limit, the gap between the gears formed by the wear causes the shaft to move. The amount of rotation of the gear obtained according to the amount of rotation does not match the design value, and it becomes impossible to secure an accurate amount of movement.

Therefore, when the wear between the gears exceeds a predetermined limit, it is necessary to quickly replace the gears. Therefore, the degree of wear between the gears, that is, the play between the gears formed by this wear. The amount of must be observed and measured at all times.

However, in the case of such a conventional actuator, when measuring the amount of play between gears, the power must be turned off and switched to manual, and then the measurement work must be performed manually. It was time-consuming.

Further, in order to ensure efficiency, it is desirable that the work of measuring the amount of play between the gears is performed immediately before the wear between the gears reaches a predetermined limit, and the timing thereof is difficult. ..

The present invention solves the above problems, and an object of the present invention is to provide an actuator capable of easily detecting the state of wear occurring between gears transmitting the rotation amount of a shaft. To do.

[0008]

In order to solve the above problems, the present invention provides, as a first invention, a plurality of gears provided on a shaft rotated by a drive source.
In the actuator that transmits the rotation amount of the drive source, a pulse generator that generates a number of pulses according to the rotation amount of the shaft, and a flow when the drive source starts the shaft and sequentially follows the gears An overcurrent detecting member that detects an overcurrent and outputs a signal in accordance with the detected timing, and a pulse of the pulse generator, and a next signal after receiving a predetermined signal of the overcurrent detecting member. And a pulse number indicator for displaying the number of pulses counted by the counting member, and adopting a means for detecting the amount of wear occurring between the gears. Is. Further, as a second invention including the first invention, the pulse generator is configured by a rotary encoder formed of a magnetic drum and a magnetic sensor, and a third invention including the first invention. As the above, the overcurrent detection member employs a means including a current sensor that detects an overcurrent flowing in the drive source and a pulse generator that generates a trigger pulse based on the output of the current sensor. Is.

[0009]

The present invention, by adopting the above means,
Based on the number of pulses displayed on the pulse number display, it is possible to know the degree of wear generated between the gears that transmit the rotation amount of the drive source.

That is, when the overcurrent detection member sequentially detects the overcurrent flowing in the drive source when each gear is driven and outputs the detection signal at this time to the counting member, the overcurrent detection member in the counting member The number of pulses sent from the pulse generator is counted based on the output signal from the pulse generator, and the result of this counting is displayed on the pulse number display.

In this case, when the amount of wear between the gears increases, the gap between the gears formed by the wear increases, so that the intervals of overcurrent that are sequentially generated when the gears are driven are long. Therefore, a time lag occurs in the signal output from the overcurrent detection member. As a result, the number of pulses counted by the counting member increases in proportion to the amount of wear between the gears, and the number of pulses displayed on the pulse number display also increases accordingly. The wear state between gears, that is, how much wear is progressing between gears can be easily known based on the number.

[0012]

Embodiments of the present invention shown in the drawings will be described below. 1 is a schematic view showing an embodiment of an actuator according to the present invention, and FIG. 4 is a block diagram for explaining an embodiment of an actuator according to the present invention.

That is, in the actuator shown in FIGS. 1 and 4, a worm gear formed by a worm 2 and a worm gear 4 is provided on a shaft 1 rotated by a motor 8 which is a drive source. Inside, the center column 5 and the sleeve 6 are provided,
The stem 7 is inserted into the inside of the sleeve 6, and at this time, the screw portions 6a and 7a are formed between the sleeve 6 and the stem 7, so that the stem 7 is driven by the driving force of the screw portions 6a and 7a. It can be moved to the axis 1
A pulse generator that generates a number of pulses according to the rotation amount of the motor, an overcurrent detection member that detects an overcurrent flowing through the motor 8, and outputs a signal according to the detected timing, and an output of this overcurrent detection member. It comprises a counting member for counting the number of pulses sent from the pulse generator based on the signal, and a pulse number display for displaying the number of pulses counted by the counting member.

The pulse generator is the magnetic drum 3b.
And a rotary encoder 3 formed by a magnetic sensor 3a
The overcurrent detection member is composed of a current sensor 9 for detecting an overcurrent flowing in the motor 8 and a pulse generator 11 for issuing a trigger pulse in accordance with the timing of the output signal of the current sensor 9. There is.

First, the mechanism of the actuator shown in FIG. 1 will be described. In FIG. 1, reference numeral 8 is a motor, which is a drive source, which connects the shaft 1 and rotates the same.

A worm gear is provided on the shaft 1 which is rotated by the rotation of the motor 8. The worm gear is formed of a worm 2 formed on the shaft 1 and a worm gear 4 that meshes with the worm 2 in a state where the axis line is orthogonal to the shaft 1.
Rotation is reduced and transmitted to the gear of the next stage.

Inside the worm gear 4 forming one of the worm gears, as shown in FIG. 2, a cylindrical center column 5 is mounted with its axis aligned with the axis of the worm gear 4. The center column 5 rotates together with the rotation of the gear 4.

Inside the center column 5, a sleeve 6 which is a kind of gear is inserted and fixed at a position corresponding to the worm gear 4. The sleeve 6 is a so-called buffer, and is made of a material that is relatively more easily worn than the slam 7 that is screwed into the sleeve 6. The sleeve 6 has a cylindrical shape and has an internal thread portion 6a formed on the inner peripheral surface thereof. That is
By providing this axis in a state where it coincides with the axis of the worm gear 4, this sleeve 6 rotates together with the center column 5 when the worm gear 4 rotates.

Inside the sleeve 6, a stem 7, which is a kind of gear, to which a valve or the like is connected, is provided in the sleeve 6 in a state of being screwed with the sleeve 6 and movable in the axial direction thereof. The stem 7 has a male screw portion 7a formed on its outer peripheral surface that is screwed into the female screw portion 6a of the sleeve 6, and the male screw portion 7a is driven by the rotation of the female screw portion 6a of the sleeve 6, and the driving force at this time causes the male screw portion 7a to be driven. The stem 7 is adapted to move relative to the sleeve 6.

A bearing 14 supports the shaft 1 in a freely rotatable state. The above actuator includes a pulse generator, an overcurrent detecting member, a counting member, and a pulse number display 12.

1 and 3, the pulse generator is composed of a rotary encoder 3 formed by a magnetic drum 3b and a magnetic sensor 3a. The magnetic drum 3b forming one of the rotary encoders 3 has its outer peripheral surface magnetized at a predetermined pitch, and is attached to the shaft 1 with its axis aligned with the axis of the axis 1. The magnetic drum 3b rotates together with the shaft 1.

By disposing the magnetic sensor 3a having an encoder, which constitutes the other part of the rotary encoder 3, at a portion corresponding to the outer peripheral surface of the magnetic drum 3b, the magnetic sensor 3a is rotated when the shaft 1 rotates. Detects the magnetized portion on the outer peripheral surface of the magnetic drum 3b and generates a number of pulses according to the resolution.

The overcurrent detection member comprises a current sensor 9 and a pulse generator 11. A current sensor 9 that constitutes one of the overcurrent detection members is connected to the motor 8 and detects an overcurrent of the motor 8 that flows when a load acts, and this output signal is sent to the pulse former 11.

In particular, when the motor 8 is started, when the worm 2 is started, and when the stem 7 is started, a large load acts on the motor 8 due to each inertial force.
An overcurrent starts to flow in the motor 8 at the time of each start-up and start-up, and as a result, the current sensor 9 sequentially detects the wave-shaped current fluctuations shown in the lower part of FIG.

As shown in FIG. 5, when the current sensor 9 detects an overcurrent flowing through the motor 8, the pulse former 11, which constitutes the other of the overcurrent detecting members, generates a trigger pulse at the timing. In particular, the information of the time t from the trigger pulse generated when the worm 2 is started to the trigger pulse generated when the stem 7 is started is given to the counter 10.

The counter 10, which is a counting member, receives the output signal of the rotary encoder 3, and based on two predetermined trigger pulses given from the pulse former 11, the rotary encoder 3 outputs the signal during the time t. The number of pulses received is counted, and the numerical information of the number of pulses counted by the counter 10 is transmitted to the pulse number display 12.

The pulse number display 12 is a counter 10
Numerical information obtained further is displayed by numbers, and the number of pulses counted by the counter 10 can be visually confirmed based on the number displayed on the pulse number display 12.

In this case, if the transmission device 13 for transmitting the numerical information obtained from the counter 10 is interposed between the counter 10 and the pulse number display 12, the pulse number display is provided at a position separated from the actuator body. It is possible to install 12.

A power source 16 supplies electricity to the rotary encoder 3, the current sensor 9 and the motor 8. Further, reference numeral 15 is a switch, which is an ON / OFF switch of a power source 16 for the motor 8.

Next, the operation of the above will be described. In this actuator, when the switch 15 is turned on and the motor 8 is rotated, the worm 2 of the shaft 1 is rotated by the rotational force of the motor 8 and then the worm 2 is rotated.
The worm gear 4 that meshes with the center column 5 and the sleeve 6 is integrated with the worm gear 4 to rotate about the stem 7, whereby the rotation of the shaft 1 causes the rotation of the sleeve 6 having an axis in a direction orthogonal to the axis. Converted as rotation.

By the rotation of the sleeve 6,
The female screw portion 6a comes to rotate along the male screw portion 7a of the stem 7, and both screw portions 6a obtained at this time,
The stem 7 is moved in the axial direction by the driving force of the shaft 7a. As a result, the shaft 1 by the motor 8 is moved.
Will be converted into a linear movement in the direction orthogonal to the axis 1.

Therefore, for example, when the valve is connected to the tip of the stem 7, the valve can be opened and closed by the operation of this actuator.

Further, when the switch 15 is turned on, an overcurrent for starting the motor 8 flows in the motor 8, so this overcurrent is detected by the current sensor 9 and a pulse is detected based on the detection signal at this time. The first trigger pulse is generated by the former 11.

When the motor 8 is started, the worm 2 is then started with a slight time delay due to the inertial force of the shaft 1 itself. At this time, since an overcurrent flows through the motor 8 due to the action of the load due to the inertial force of the shaft 1, the current sensor 9 detects the overcurrent even when the worm 2 is started, and the pulse is detected based on the detection signal at this time. A second trigger pulse is generated by the former 11.

When the worm gear 4 is rotated by the start of the worm 2, the center column 5 and the sleeve 6 are simultaneously rotated, but the play between the screw portions 6a and 7a formed between the sleeve 6 and the stem 7 is caused. Depending on the amount of
The start of the stem 7 will be delayed from the start of the worm 2 by the required time.

Further, when the stem 7 is started, a load due to its own inertial force acts on the motor 8 so that an overcurrent flows, so that the current sensor 9 also detects the overcurrent when the stem 7 is started. The pulse signal is detected, and the third trigger pulse is generated by the pulse generator 11 based on the detection signal at this time.

As a result, the pulse former 11 obtains information on the time t from the second trigger pulse to the third trigger pulse, that is, from the start of the worm 2 to the start of the stem 7, and this information is obtained. Is given to the counter 10.

On the other hand, in the rotary encoder 3, a number of pulses corresponding to the amount of rotation of the shaft 1 are generated, and these pulses are sequentially sent to the counter 10, and based on the information of the time t obtained from the pulse former 11. The counter 10 counts the number of pulses sent from the rotary encoder 3 during time t.

That is, the counter 10 includes the pulse former 1
When the second trigger pulse is generated from 1, the counting of the pulse sent from the rotary encoder 3 is started,
Then, when the pulse generator 11 generates the third trigger pulse, the counting of the pulses sent from the rotary encoder 3 is finished, and the worm 2
The number of pulses of the rotary encoder 3 sent during the time t from the start of the above to the start of the stem 7 is counted.

The numerical information on the number of pulses counted by the counter 10 is sent to the pulse number display 12, and the number of pulses counted by the counter 10 is displayed by the pulse number display 12 as a number. It is like this.

As a result, the time t from the start of the worm 2 to the start of the stem 7 is long or short depending on the amount of play between the screw portions 6a formed between the sleeve 6 and the stem 7 and 7a. However, since the numerical value displayed on the pulse number display 12 becomes large accordingly, the amount of play between the screw portions 6a and 7a becomes proportional to the numerical value displayed on the pulse number display 12, As a result, the amount of play between the screw portions 6a and 7a can be determined by the numerical value.

Here, when foreign matter such as dust enters the screw portions 6a, 7a formed between the sleeve 6 and the stem 7 and friction occurs in the screw portions 6a, 7a, wear occurs, as shown in FIG. As shown, the amount of play between the threaded portions 6a, 7a increases.

In this case, since the sleeve 6 is made of a material that is more easily worn than the stem 7, the threaded portion 6a,
The abrasion between 7a mainly occurs unilaterally in the female screw portion 6a of the sleeve 6.

As a result, a gap is formed between the screw portions 6a and 7a by the amount of wear of the female screw portion 6a of the sleeve 6a, and this gap causes wear especially at the time of starting the stem 7. There will be a time lag compared to when the stem 7 is started when it is not present.

This time lag becomes longer as the amount of wear of the female screw portion 6a of the sleeve 6 increases, and as a result,
The time t from the start of the worm 2 to the start of the stem 7
Becomes longer in proportion to the wear amount of the female screw portion 6a.

As described above, as the time t becomes longer, the number of pulses from the rotary encoder 3 counted by the counter 10 also increases, and the number displayed on the pulse number display 12 also increases accordingly. As a result, as a result, it is possible to know the degree of wear generated between the screw portions 6a and 7a formed between the sleeve 6 and the stem 7.

At this time, if the relationship between the wear amount between the screw portions 6a and 7a and the number displayed on the pulse number display 12 is obtained in advance, the screw portion can be calculated from the number displayed on the pulse number display 12. The amount of wear between 6a and 7a can be accurately known, and if the upper limit of the numerical value displayed on the pulse number display 12 is set based on the usage limit of the sleeve 6 and the stem 7 due to wear, It is now possible to easily know when to replace parts.

Further, the pulse number display 12 and the counter 10
When the transmission device 13 is interposed between the actuator and the actuator, the pulse number indicator 12 can be provided at a place separated from the actuator body. For example, as shown in FIG. 4, when a pulse number indicator is provided in the central control room installed at a place distant from the actuator body, the information on the pulse number obtained from the counter 10 is transmitted by the transmission device 13 Is transmitted to the pulse number display 12 without being attenuated.

Therefore, for example, if all the pulse number indicators 12 for a plurality of actuators are provided in the central control room, the amount of wear generated between the gears of the respective actuators can be monitored in the central control room in an integrated manner. Accompanied by,
For example, as often seen in plants, even when actuators are scattered on a large site, the inspection work can be extremely facilitated.

Further, when the sleeve 6 is made of a material that is more easily worn than the stem 7, the sleeve 6 is unidirectionally worn between the sleeve 6 and the stem 7. When replacing parts, only the sleeve 6 needs to be replaced.
The replacement work and the maintenance of the actuator can be facilitated.

Although the rotary encoder 3 formed of the magnetic drum 3b and the magnetic sensor 3a is used as the pulse generator in the above embodiment, the pulse generator generates a number of pulses corresponding to the rotation amount of the shaft 1. If it is good.

The overcurrent detecting member is also composed of the current sensor 9 and the pulse generator 11 in the above embodiment, but detects an overcurrent flowing through the drive source and emits a signal in accordance with the detected timing. If it is a thing, it is not limited to the above and can be applied.

Further, regarding the pulse number display 12,
In the above embodiment, the numbers are displayed, but any pulse number indicator can be applied as long as the number of pulses counted by the counting member can be recognized. It is a thing.

In the above embodiment, the worm gear and the screw portion are used to transmit the power, but the present invention is not limited to this, and the present invention can be applied as long as a plurality of gears are provided. Therefore, the amount of wear between the gears can be detected, and therefore the invention can be applied to, for example, the detection of screw loosening, and the application is not limited.

Further, in the above embodiment, the counter 1
The time t for counting the number of pulses at 0 was determined by the time from warm start to stem start, but it may be determined by the time from motor start to stem start. It suffices that the time t is determined according to the timing.

[0056]

As described above, according to the present invention, a pulse generator for generating a number of pulses corresponding to the amount of rotation of a shaft, and an overcurrent flowing in a drive source are detected in an actuator, and the detected timing is detected. An overcurrent detection member that emits a signal at
A counting member for counting the number of pulses sent from the pulse generator based on the output signal of the overcurrent detection member;
By providing a pulse number indicator that displays the number of pulses counted by this counting member, the pulse number indicator displays the degree of wear that has occurred between the gears for transmitting the amount of shaft rotation. It can be known accurately and easily based on the number of pulses that are applied.

Therefore, there is an effect that it becomes possible to easily judge the replacement time of parts such as gears based on the number of pulses displayed on the pulse number display.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing an actuator according to the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a view showing a threaded portion formed between a sleeve and a stem, and is a view showing a state in which wear has occurred.

FIG. 4 is a block diagram illustrating an embodiment of an actuator according to the present invention.

FIG. 5 is a diagram showing a relationship between waveforms obtained by a current sensor and a pulse former.

[Explanation of symbols]

 1 ... Shaft 2 ... Worm 3 ... Rotary encoder (pulse generator) 3a ... Magnetic sensor 3b ... Magnetic drum 4 ... Worm gear 5 ... Center column 6 ... Sleeve 6a ... + Female thread 7 ... … Stem 7a …… Male thread 8 …… Motor (driving source) 9 …… Current sensor (overcurrent detection member) 10 …… Counter 11 …… Pulse generator (overcurrent detection member) 12 …… Pulse number indicator 13 ...... Transmission device 14 …… Bearing 15 …… Switch 16 …… Power supply

Claims (3)

[Claims] 1. An actuator for transmitting the rotation amount of the drive source (8) by providing a plurality of gears on the shaft (1) rotated by the drive source (8), the rotation amount of the shaft (1). A pulse generator (3) for generating a number of pulses corresponding to the above, and an overcurrent flowing when the drive source (8) starts the shaft (1) and sequentially drives each gear,
An overcurrent detection member (9, 11) that emits a signal in accordance with the detected timing, and a pulse of the pulse generator (3) are received, and at the same time, the overcurrent detection member (9, 1).
A counting member (10) for counting the number of pulses between the reception of the predetermined signal of 1) and the reception of the next signal, and a pulse number display for displaying the number of pulses counted by the counting member (10) (12) An actuator, characterized in that the amount of wear occurring between the gears is detected. 2. The pulse generator comprises a magnetic drum (3
2. The actuator according to claim 1, comprising a rotary encoder (3) formed by b) and a magnetic sensor (3a). 3. The overcurrent detection member includes a current sensor (9) for detecting an overcurrent flowing in the drive source (8),
A pulse former (11) for generating a trigger pulse based on the output of the current sensor (9).
Actuator described.