JP2001311644A - Rotary level detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary level detector sufficiently compact and capable of detecting the stop of rotation of output shaft of a motor with a high reliability, in a rotary level detector for powder and particle in a vessel. SOLUTION: A rotary encoder 70 detecting the stop of rotation of the output shaft 3 to the casing 2b of a motor 2, an interrupter 71 and a circuit part 72, are arranged in the casing 2b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary level detector for detecting the level of a granular material such as cement or flour in a container.

[0002]

2. Description of the Related Art Conventionally, as this type of rotary level detecting device, for example, there is one as shown in FIG. 7 (see Japanese Utility Model Laid-Open No. 5-36321). This device is mounted on a side wall 101 of a tank and detects the level of a granular material (storage material) 102 such as cement or flour, and is provided at a tip of a motor 103 and an output shaft 104 of the motor 103. A plate-like blade 108 is provided. Then, a motor 103 is attached to the side wall 101 of the tank by a bracket or the like (not shown) so that the blade 108 is housed in the tank, and an output shaft 104 of the motor 103 passes through the side wall 101 of the tank via a seal member 105. .

[0003] The blade 108 is rotated by the motor 103 without resistance when not in contact with the granular material 102, but the level (height) of the granular material 102 becomes high in the tank. The resistance received from the granular material 102 increases in accordance with the degree of contact, and when the degree of contact becomes greater than or equal to a predetermined value, the motor 103 is overloaded, and an overcurrent flows through the drive coil of the motor 103.
It is detected that a predetermined amount of granular material 102 has been stored in the tank. However, this alone cannot detect that a predetermined amount of the granular material 102 has been stored in the tank when the rotation of the output shaft 104 and thus the blade 108 is stopped due to the disconnection of the drive coil of the motor 103 or the failure of the drive circuit. .

Therefore, in this device, a disk 109 having a plurality of small holes 110 provided at equal intervals on a peripheral portion is attached to an output shaft 104 of the motor 103 between a casing of the motor 103 and a side wall 101 of the tank. A pair of light-emitting elements and a light-receiving element (not shown) are arranged so as to sandwich the peripheral edge. Then, the output shaft 104 of the motor 103
The light from the light emitting element is intermittently
A signal generated by passing through the light-receiving element and entering the light-receiving element is detected by a circuit unit (not shown), and when the signal is no longer interrupted, the stop of the rotation of the output shaft 104 is detected and a failure notification signal is output. I have to.

[0005]

However, in the rotary level detecting device having such a configuration, the disk 109 for detecting the stop of the rotation of the output shaft 104 of the motor 103, the light emitting element and the light receiving element, and the circuit section But all are motor 103
Because it is located outside the casing, the entire device is not compact. Further, since the disk 109, the light emitting element and the light receiving element are exposed to the atmosphere in which the powder and the like 102 can exist, the reliability of detecting the stop of the rotation of the output shaft 104 cannot be further improved.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in consideration of the above problems, and provides a sufficiently compact and highly reliable rotation of an output shaft of a motor. It is an object of the present invention to provide an apparatus capable of detecting the stop of the operation.

[0007]

According to a first aspect of the present invention, there is provided a rotary level detecting apparatus comprising: a motor; a spindle connected to an output shaft of the motor; and a casing of the motor. A relatively rotatable fixing member, and a rotation preventing means for applying an elastic force to the fixing member to prevent the casing of the motor from rotating in a direction opposite to the rotation direction of the output shaft of the motor; Switch means for detecting when the casing of the motor has rotated to a predetermined angle against the elastic force of the rotation preventing means. The motor, the fixing member, the rotation preventing means and the switch means are housed in a case of the apparatus, and the spindle is supported by the case.

Here, the fixing member is fixed to the case, the spindle protrudes outward from the case, and a blade is attached to the protruding tip.
Further, such that the spindle penetrates the wall of the container that stores the object to be measured, which is a granular material, and the blades are located in the container.
The case has a flange attached to the wall. Further, the motor includes a rotary encoder, an interrupter, and a circuit unit for detecting stop of rotation of the output shaft with respect to the casing in the casing.

According to the first aspect of the present invention, the rotary encoder, the interrupter and the circuit for detecting the stop of rotation of the output shaft with respect to the casing are arranged in the casing of the motor. And the stop of the rotation of the output shaft can be detected with sufficiently high reliability.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a rotary level detector according to an embodiment of the present invention. First,
The configuration of this device will be described. The rotary level detector 1 is attached to a side wall of a tank (container) to detect the level of a stored object (measured object which is a granular material), as shown in a side view of FIG. , A motor 2, a spindle 7 coupled to an output shaft 3 of the motor 2 via a joint 4, fixed members (first and second frames) 13, 20 rotatable relative to a casing 2 b of the motor 2,
A rotation preventing means 69 for applying an elastic force to the fixing members 13 and 20 so as to prevent the casing 2b of the motor 2 from rotating in a direction opposite to the rotation direction A of the output shaft 3 of the motor 2; Switch means (first and second limit switches) 14 and 15 for detecting when the casing 2b of the motor 2 rotates to a predetermined angle against the elastic force of the rotation preventing means 69 are provided.

The case 10 of the rotary level detector 1
Accommodates the motor 2, the fixing members 13 and 20, the rotation preventing means 69 and the switch means 14 and 15, and supports the spindle 7 axially. The rotary level detecting device 1 is positioned such that the spindle 7 projecting outward from the case 10 penetrates the wall of the tank, and the blade 5 attached to the tip thereof is housed in the tank. The case 10 is mounted on the side wall of the tank by bolts or the like through a plurality of mounting holes 6 formed in a mounting portion (flange) 10 a of the case 10.

As shown in the sectional side view of the main part of FIG. 4, a pair of first and second mounting parts extending from the front and rear in the axial direction of the motor 2 are attached to mounting portions extending left and right (front and rear in FIG. 1. The first and second motor covers 21a and 21b are riveted, and the casing 2b of the motor 2 is sandwiched between the first and second motor covers 21a and 21b to cover the front and rear portions, and is integrated with the motor cover 21. I have. The output shaft 3 of the motor 2 extends axially forward of the motor 2, projects out of the casing 2 b of the motor 2 and the first motor cover 21 a on the front side, and extends through a first frame (fixed member) 13. It is inserted into the shaft fixing portion 17 and is fixed by screws 68.

At the front of the joint 4, a pair of cutouts 66, 66 facing in the radial direction are provided.
is inserted and the elastic locking member 67 (FIG. 5) made of a spring material is attached as a clutch to the cutout portion 66, so that a predetermined load (a load at which a casing 2b of the motor 2 described later rotates) is applied. (Greater than) are locked to the joint 4 so that they cannot rotate relative to each other. That is, a slip occurs between the elastic locking member 67 and the spindle 7 due to an impact load applied when the falling object collides with the blade 5 in FIG. Is disconnected to protect the rotary level detector 1. Further, the spindle 7 is supported by the bearing portion 11 of the case 10 via the metal bearing 11a and the ball bearing 11b in a state sealed by the oil seal portion 8 and the cap nut 9.

On the other hand, as shown in FIG. 4, a support shaft 40 is caulked on the rear second motor cover 21b so as to be coaxial with a rearward extension line of the output shaft 3 of the motor. After being inserted into the spacer 43, the 40 is supported by the bearing 22 which is caulked to the second frame (fixing member) 20, and is prevented from coming off by the E-ring 42 via the sliding member 41. The second frame 20 is fixed to the case 10 of FIG. 1 (the fixing state is not shown).

That is, the entire motor 2 includes a joint 4 (a shaft fixing portion 17 of the case 10) and a spindle 7 in the front.
And bearing 11 via bearings 11a and 11b.
At the rear, and is supported by the case 10 via the cover 21, the support shaft 40, the bearing 22, and the second frame 20. Also, as shown in FIG.
4 protrudes from the first motor cover 21a in the axial direction forward in parallel with the output shaft 3 of the motor 2,
Are erected from the second motor cover 21b toward the rear in the axial direction.

As shown in FIG. 5, on the front side of the first frame 13, a pair of limit switches 14 and 15 are connected to switch operation knobs 14a and 15a (in FIG. 5, the switch operation knob 14a is It is buried in the main body of the limit switch 14 so that it is mounted facing each other (not shown).
(FIG. 3) are erected, so their swaged end faces are visible on the front side. Shaft fixing part 17 of joint 4
Above (FIG. 4), a large-diameter hole 50 through which the columnar pressing member 24 passes is provided in the first frame 13. When the columnar pressing member 24 is displaced leftward or rightward, one of the operating knobs 14a, 15a of the first and second limit switches 14, 15 is pressed, and the other is released from the pressed state. . These first and second limit switches 14 and 15 are connected to the switch means 14,
15.

As shown in FIG. 3, the second frame 20
The cross section is formed in an inverted L-shape (FIG. 4), and the first frame 13
Each of the plurality of supporting columns 16 erected on the first frame 13 is attached to a distal end of the supporting column 16, and maintains a constant interval with the first frame 13. That is, the first frame 13 is fixedly supported by the case 10 (FIG. 1) via the column 16 and the second frame 20. Therefore, the fixing members (first and second frames) 13 and 20 are fixedly accommodated in the case 10 and are rotatable relative to the casing 2 b of the motor 2. As shown in FIG. 4, a large-diameter long hole 51 through which the columnar boss 25 erected on the second motor cover 21b passes is bored in the second frame 20 above the bearing 22.

As shown in FIG. 6, one end of a coil spring 27 is attached to a mounting piece 26 provided upright on the back side of the second frame 20, and the other end of the coil spring 27 is attached to a columnar boss 25. 5 is biased so that the columnar pressing member 24 of FIG. 5 presses the switch operating knob 14a of the first limit switch 14 via the motor cover 21 of FIG. Coil spring 27, mounting piece 2 of FIG.
6, the columnar boss 25 and the motor cover 21 of FIG.

Further, as shown in FIG.
8 is attached to the back side of the second frame 20, and a terminal board 29 to which a lead wire for connecting the motor 2 (FIG. 3) and an external drive circuit (not shown) is connected is fixed by bolts 30. . In addition, the lead wire is a large-diameter lead outlet 31 provided on the lower side of the case 10 of FIG.
From the outside. Further, the items stored in the case 10 are hermetically sealed by the cap 32 of the case 10 via the waterproof rubber seal member 33.

Next, the inside of the motor 2 will be described.
As shown in FIG. 2 which is a side cross-sectional view of the motor 2, the motor 2 includes an annular stator (drive coil) 73 fixed to the bottom (the right part in FIG. 2) of a cylindrical can-shaped casing 2 b,
And a rotor 74 that rotates about the center axis of the casing 2b as a rotation axis by the stator 73 that is energized. The stator 73 and the rotator 74 constitute a rotation drive unit of the motor 2.

The gear section of the motor 2 is on the left side of the rotation driving sections 73 and 74. The gear portion has, for example, five two-stage gears 75A, 75B, 75C... To which two gears having different diameters are fixed coaxially, and each of the two-stage gears 75A, 75B, 75
The rotation axis of C ... is parallel to the rotation axis of the rotor 74. The gear 74 a provided on the rotor 74 is the first two-stage gear 7.
5A, and the small diameter portion of the first two-stage gear 75A meshes with the large diameter portion of the second two-stage gear 75B.
Are engaged with the large-diameter portion of the third two-stage gear 75C. Similarly, the two-stage gears 75C are engaged with each other, and are not shown (fourth and fifth two-stage gears 75D, 75D). 7
5E is located closer to the paper surface of FIG. 2) The small diameter portion of the fifth two-stage gear 75E meshes with the gear 4a provided on the output shaft 3 to sufficiently reduce the rotation of the rotor 74. It is transmitted to the output shaft 3.

The rotor 74 and the two-stage gears 75A, 7A
5B, 75C... And the output shaft 3
Two partition plates 76A, 76B provided inside the casing 2b in parallel with the bottom of the casing 2b are rotatably supported via bearings (not shown).

Further, in the casing 2b, the gear 75
On the left side of A, 75B, 75C,..., The motor 2 has a rotary encoder 70 for detecting rotation stop of the output shaft 3 with respect to the casing 2b, an interrupter 71, and a circuit unit 72. The interrupter 71
A pair of light-emitting elements and light-receiving elements are opposed to each other, and are fixed to the casing 2b so as to sandwich the periphery of the rotary encoder 70 between the two elements. In the peripheral portion of the disk-shaped rotary encoder 70 fixed to the output shaft 3 of the motor 2, substantially rectangular irregularities (slits) are formed at regular intervals when viewed from the rotation axis direction. Similarly to the technique, by rotating the output shaft 3 at a predetermined speed, the light from the light emitting element intermittently and periodically passes through the concave portion of the peripheral portion of the rotary encoder 70 and is incident on the light receiving element, and the generated signal is converted into a circuit. The stop of the rotation of the output shaft 3 is detected by the detection by the unit 72 and the stop of the signal.

More specifically, a predetermined delay time is set in a timer circuit of the circuit section 72, and the timer circuit monitors the pulse width of a signal generated by the light receiving element of the interrupter 71. Then, a failure notification signal can be output to failure notification means such as a buzzer, a warning light, and the like outside the apparatus (not shown). A current is supplied from a stator (drive coil) 73 as a power supply for the circuit section 72. The lead wire for connecting the circuit section 72 and the failure notifying means is drawn out through the terminal board mounting plate 28 of FIG. 1 similarly to the lead wire for connecting the motor 2 and the external drive circuit. It is drawn out from the mouth 31.

Next, the operation of the rotary level detecting device 1 will be described. If the level of the object stored in the tank has not reached the detection level, the blade 5
Is rotationally driven in one direction A by a motor 2 via a spindle 7. At this time, the motor 2 has the output shaft 3 supported by the shaft fixing portion 17 at the front, supported by the bearing 22 via the motor cover 21 and the support shaft 40 at the rear, and fixed to the second motor cover 21b. When the columnar boss 25 is pulled in the direction of the mounting plate 26 by the coil spring 27 shown in FIG. 6, the casing 2b of the motor 2 shown in FIG.
3 and 20 (or the case 10 to which they are fixed) are in a stopped state.

That is, the coil spring 27, the mounting piece 26,
The rotation preventing means 69 composed of the columnar boss 25 and the motor cover 21 applies the motor 2 to the fixed members 13 and 20.
An elastic force is applied to prevent the casing 2b from rotating in the direction B opposite to the direction A of rotation of the output shaft 3 of the motor 2. Thereby, the pressing member 24 in FIG. 5 is at the position shown by the solid line, and constantly presses the switch operating knob 14 a of the first limit switch 14.

When the level of the object to be measured reaches the detection level, the object to be measured becomes an obstacle to the rotation of the blades 5 in FIG. Is exceeded, the rotation of the output shaft 3 of the motor 2 with respect to the case 10 and the fixing members 13 and 20 is stopped. As a result, the casing 2b of the motor 2
With respect to the fixing members 13 and 20, the column boss 25 rotates together with the motor cover 21 in the direction B opposite to the rotation direction A of the output shaft 3 so that the columnar boss 25 moves in the left direction B (the coil spring 27
In the direction in which it is stretched).

In other words, by pulling the coil spring 27 in the extending direction, in FIG. 5, the motor cover 21 and the motor casing 2b rotate rightward B in FIG. 5 and the pressing member 24 fixed to the first motor cover 21a.
Is displaced to the position indicated by the dashed line. As a result, the pressed state of the switch operating knob 14a of the first limit switch 14 is released, and it is detected by an external circuit (not shown) connected to the first limit switch 14 that the measured object has reached a predetermined level. On the other hand, the switch operating knob 15a of the second limit switch 15 is pressed, and the drive of the motor 2 is stopped by a motor control circuit (not shown) connected to the second limit switch 15. That is, switch means (first and second limit switches)
14 and 15 detect when the casing 2b of the motor 2 rotates to a predetermined angle against the elastic force of the rotation preventing means 69 (FIG. 6).

The above is a normal operation. However, in FIG. 1, the rotation of the output shaft 3 with respect to the casing 2b is stopped due to an abnormality such as a disconnection of the drive coil 73 (FIG. 2) of the motor 2 or a failure of the drive circuit. Figure 2 fixed to the case
The rotation of the rotary encoder 70 is also stopped, and the level of the signal generated by the light receiving element of the interrupter 71 does not change within a predetermined delay time, so that the circuit unit 72 detects the stop of the rotation of the output shaft 3. . Then, the circuit section 72
A warning by sound or light is issued from a failure notification means such as a buzzer or a warning light (not shown) according to the failure notification signal output from the controller, and the worker stops supplying the powder to the tank. By taking appropriate measures such as the above, it is possible to prevent the occurrence of such a problem that the granular material is charged into the tank in excess of a predetermined amount and overflows.

Here, according to the apparatus of this embodiment, the rotary encoder 70 for detecting the stop of the rotation of the output shaft 3 with respect to the casing 2b, the interrupter 71, and the circuit section 72 are arranged in the casing 2b of the motor 2. As a result, the entire device becomes sufficiently compact. Also,
In FIG. 1, the case 10 is sealed by the oil seal portion 8 and the cap nut 9. However, since the spindle 7 is rotated, the seal cannot be completely formed, and there is a possibility that the granular material may enter the case 10 slightly. is there. But,
According to the device of the present embodiment, as shown in FIG. 2, the rotary encoder 70, the interrupter 71, and the circuit section 72 are arranged in the casing 2b of the motor 2 and are exposed in the case 10 (FIG. 1). Since there is no powder or granules, it is possible to detect the stop of the rotation of the output shaft 3 with sufficiently high reliability without causing a malfunction between the light emitting element and the light receiving element of the interrupter 71 and causing a malfunction.

[0031]

As described above in detail, according to the present invention, the rotary encoder, the interrupter and the circuit for detecting the stop of the rotation of the output shaft with respect to the casing are arranged in the casing of the motor. In addition, the whole device becomes sufficiently compact, and the stop of the rotation of the output shaft can be detected with sufficiently high reliability.

[Brief description of the drawings]

FIG. 1 is a side view showing a rotary level detection device according to an embodiment of the present invention.

FIG. 2 is a side sectional view of a motor of the same device.

FIG. 3 is a side view showing a rotation driving unit and the like of the apparatus.

FIG. 4 is a cross-sectional side view of a main part showing a rotation driving unit and the like of the apparatus.

FIG. 5 is a front view showing a front side of a first frame of the device.

FIG. 6 is a rear view showing the back side of the second frame of the device.

FIG. 7 is a perspective view showing a conventional rotary level detection device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotary level detection device, 2 ... Motor, 2b ... Motor casing, 3 ... Motor output shaft, 5 ... Blade, 7 ... Spindle, 10 ... Case, 10a ... Case flange,
13, 20 ... fixing member, 14, 15 ... switch means, 6
9: rotation prevention means, 70: rotary encoder, 71
... Interrupter, 72 ... Circuit part, A ... Rotation direction of the output shaft of the motor, B ... Direction opposite to the rotation direction of the output shaft of the motor.

Claims (1)

[Claims] A motor, a spindle connected to an output shaft of the motor, a fixed member rotatable relative to a casing of the motor, and a casing of the motor with respect to the fixed member. Rotation preventing means for applying an elastic force so as to prevent rotation in a direction opposite to the rotation direction, and when the casing of the motor rotates to a predetermined angle against the elastic force of the rotation preventing means, And a case housing the motor, the fixing member, the rotation preventing means and the switch means, and supporting the spindle. The fixing member is fixed to the case, and the spindle is A blade protruding outward from the case, a blade is attached to the protruding tip, and the spindle penetrates a wall of a container for accommodating an object to be measured which is a granular material, and Wherein the case has a flange attached to the wall such that the motor is positioned within the container, wherein the motor detects, in the casing, a stop of rotation of the output shaft with respect to the casing. A rotary level detection device comprising a rotary encoder, an interrupter, and a circuit unit.