JP3284153B2 - Motor overload detection structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for detecting an excessive load of a motor used in a rotary level detecting device used for detecting the level of a granular material or a liquid in a container.

[0002]

2. Description of the Related Art A conventional example of a structure for detecting an overload of a motor of this kind will be described in detail by taking a rotary level detector as an example. That is, in FIG. 10, reference numeral 1 denotes a rotary level detecting device which is attached to a side wall of a tank (not shown) and detects the level of stored items. That is,
The rotary level detecting device 1 includes a motor 2, a plate-like blade 5 connected to a rotating shaft 3 of the motor 2 via a joint 4, a case 10 for housing the motor 2, and the like. The rotary level detecting device 1 is positioned such that the plate-like blade 5 is housed in a tank, and the case 1
It is attached to the side wall of the tank by bolts and the like through a plurality of attachment holes 6 drilled in the 0 attachment portion 10a.

[0003] Incidentally, 7 is a shaft, 8 is an oil seal portion, 9 is a cap nut, and 11 is a bearing portion . Reference numeral 12 denotes a rotary drive device, the detailed structure of which will be described below with reference to FIGS.

[0004] That is, in FIGS. 11 to 14, the rotating shaft 3 of the motor 2 protrudes both forward and rearward of the motor 2, and a stator (or a cover for covering the stator , ie , a cover of the motor 2) of the motor 2. A columnar pressing member 24 protrudes forward from the case ) in parallel with the rotation shaft 3 of the motor 2 and a columnar boss 25 protrudes rearwardly.

A first frame 13 has a pair of limit switches 14 and 15 mounted on its front surface such that switch operating knobs 14a and 15a face each other, and a plurality of columns 16 standing on its rear surface. ing. The first frame 13 has a bearing 17 of the rotating shaft 3 of the motor 2.
Is mounted, and a large-diameter hole 90 through which the columnar pressing member 24 passes is provided above. When the columnar pressing member 24 is displaced leftward or rightward, the operating knobs 14 of the limit switches 14 and 15 are moved.
a, 15a, and the other is released from the pressed state.

Reference numeral 20 denotes a second frame, which is formed in an inverted L-shape in cross section and is attached to each of the distal ends of the plurality of columns 16 so as to maintain a constant distance from the first frame 13. The second frame 20 includes a bearing 22.
Is attached.

The rotating shaft 3 protruding forward and rearward of the motor 2 has its protruding portion supported by the bearings 17 and 22 so that the motor 2
The whole is supported. Above the bearing 22, a columnar boss 25 erected on the stator of the motor 2 is provided.
A long hole 91 through which a large diameter passes is formed.

Reference numeral 26 denotes a mounting piece provided upright on the second frame 20, to which one end of a coil spring 27 is mounted, and the other end of which is always a columnar boss 25.
And the columnar pressing member 24 is urged to press the switch operating knob 14a of the first limit switch 14.

Reference numeral 28 denotes a terminal board mounting plate, which is mounted on the back side of the second frame 20 and has a terminal board 29 to which a lead wire for electrically connecting the motor 2 and an external drive circuit (not shown) is connected. 30 is attached and fixed. The lead wire is drawn out from a large-diameter lead wire outlet 31 provided on the lower side of the case 10. Reference numeral 32 denotes a cap of the case 10, and reference numeral 33 denotes a waterproof rubber seal member.

Note that there are two limit switches (reference numeral 1).
4 and 15) are provided.
Even if the rotation direction of the rotating shaft 3 of the motor 2 changes depending on the purpose, one device can be used in common.

In the above configuration, when the level of the object stored in the tank does not reach the detection level, the blade 5 is driven to rotate by the motor 2 via the shaft 7. At this time, the motor 2 has the rotating shaft 3 supported by the bearings 17 and 22, and the columnar boss 25 fixed to the stator is pulled in the direction of the mounting piece 26 by the coil spring 27 so that the two frames 13 and 20 ( Alternatively, the stator of the motor 2 is stopped as if it were fixed and supported with respect to the case 10). Thus, the columnar pressing member 24 is at the position indicated by the solid line in FIG. 12 and constantly presses the switch operating knob 14a of the first limit switch 14.

Next, 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 and a large load is applied to the rotation of the motor 2. When the value exceeds a predetermined size, the rotation of the rotating shaft 3 of the motor 2 is stopped. As a result, the columnar boss 25 is displaced in the left direction in FIG. 13 (the direction in which the coil spring 27 is stretched) as the stator of the motor 2 tries to rotate in the opposite direction to the rotation direction of the rotating shaft 3.

In other words, the coil spring 27 is pulled in the direction in which it extends, and in FIG. 12, the stator rotates in the clockwise direction indicated by the arrow, and the columnar pressing member 24 of FIG.
By displacing to the position indicated by the dashed line, the pressed state of the switch operating knob 14a of the first limit switch 14 is released, and the switch operating knob 15a of the second limit switch 15 is pressed. It is detected that the object has reached a predetermined level.

[0014]

However, in the case of the motor having the above-described structure, if the motor 2 breaks down or reaches the maximum service life, the lead wires of the terminal board 29 are removed after the cap 32 is removed. The mounting screw must be loosened, the lead wire must be pulled out from the lead wire outlet 31, and the entire rotary drive device 12 must be taken out of the case 10.

In the case of attachment, the rotary drive 1
After the entire 2 is stored in the case 10, the lead wire is inserted into the case 10 from the lead wire outlet 31, the lead wire is pulled in the narrow space in the direction of the cap 32, and the lead wire is attached to the terminal board 29 with a lead wire mounting screw. I had to screw it.

[0016] Therefore, in order to respond to the recent user's tendency to replace only broken parts and reduce the maintenance cost, it is necessary to replace only the motor 2 having a short life. After taking out the entire rotary drive device 12, the bolts are removed, and the first frame 13 and the second
After disassembling the frame 20 separately, the motor 2 must be replaced and reassembled, which takes a lot of man-hours, and it is cheaper to replace the entire rotary drive device 12 instead. there were.

The present invention has been made in view of the above problems, and an object thereof is to make it possible to easily and easily replace a motor.

[0018]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
In the motor overload detecting structure according to the present invention , the mounting means is provided with a bearing for supporting a rotating shaft of the motor, and the mounting means is disposed between the mounting means and the motor, and provided on the mounting means. Fixed mounting means rotatably mounted on a bearing and allowing the stator side of the motor to be easily removed
A movable plate which is fixed by, when an excessive load to the rotation shaft of the motor is applied, and a spring means for pulling the stator side of the motor in the rotation direction of the rotating shaft of the motor,
When the stator side of the motor against the spring force of the spring means is rotated more than a predetermined angle, and a switch means for detecting it.

According to the present invention , the motor can be removed simply by removing the fixed mounting means such as the mounting screw of the motor from the movable plate, so that the motor can be easily replaced.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of an embodiment according to the present invention will be described below in detail with reference to the same rotary type level detector as that shown in the conventional example. First, in FIGS. 1 to 9, the same or equivalent components as those described in the conventional example shown in FIGS. 10 to 14 are denoted by the same reference numerals, and detailed description thereof will be omitted.

Reference numeral 40 denotes a third frame (attachment means) which is formed by folding a single metal plate downward from the central portion by 90 degrees backward, and further by bending the tip portion further upward by 90 degrees. A terminal board mounting portion 40a is formed in the portion. In addition, in the middle part of the tip part folded back by 90 degrees,
A large notch is formed, and terminal board mounting portions 40a are formed at both ends of the notch.

The third frame 40 includes the blade 5
<br/> bearing only 4 2 in which the second shaft 99 which is connected via a joint 4 to the first shaft 7 is supported rotatably mounted is provided. The terminal board mounting part 40
A is provided with a hole 40b for attaching the terminal board 29 with screws.

Reference numerals 43 and 44 denote a pair of movable pieces arranged in a symmetrical shape, and are urged in a direction of always approaching each other by a coil spring (spring means) 27, that is, inwardly of each other. Opposite sides 43a, on both sides of a stopper 40c cut and raised from the frame 40,
44a is in contact, and are each movable piece 43, 44 attached to the third frame 40 for rotation about a rotation axis 4 6. Further, the pair of movable pieces 43, 4
A pressing operation piece 50b cut and raised from a motor mounting plate (movable plate) 50 described later is positioned between the opposing sides 43a and 44a of the fourth. The pressing member 5
The width of 0b is set smaller than the width of the stopper 40c.

A switch actuating member 45 is fixedly attached to the upper end of the third frame 40 and has an L-shaped cross section. 45a and 45b are formed in a trapezoidal shape. Further, each of the convex portions 45a and 45b has two first and second limit switches (switch hands) to be described later.
Step) Rollers 14 of working pieces 14 c and 15 c of 14 and 15
b and 15b move while rolling.

The lengths of the flat tops of the convex portions 45a and 45b formed on the switch operating member 45 are set differently.

Reference numeral 50 denotes a motor mounting plate formed in an inverted triangle.
(Movable plate) , as shown in FIG.
(Attaching means) and the motor 2, and the third
The upper edge 5 is rotatably mounted on a bearing 42 mounted on the frame 40 and is normally horizontal.
In the central portion of Oa, a pressing operation piece 50b is cut and raised at a right angle so as to be located between the pair of movable pieces 43 and 44.

The stopper 40c of the third frame 40
A rectangular hole 40d is drilled at the lower position where is provided, and the pressing operation piece 50b is displaced left and right in the hole 40d. Further, bosses 51, 51 are provided upright at the upper end corners of the motor mounting plate 50, respectively.
The mounting portions 2a, 2a of the motor 2 are screwed and fixed to the motors 1 and 51 by bolts. That is, the motor mounting plate 50
The stator side of the motor 2 is fixed to the (movable plate).

Reference numeral 99 denotes a second shaft, which is formed with an engagement hole 99a into which the rotary shaft 3 of the motor 2 (a cut-out portion is formed on a part of the peripheral surface so as to form a flat portion). A flat portion is formed on a part of the inner peripheral surface.

Next, a rotary level detector for explaining the present invention will be described with reference to FIGS. First, the rotation shaft 3 of the motor 2 is
The mounting portions 2a, 2a projecting outward from both sides of the stator are screwed into the corresponding bosses 51, 51, respectively, and attached to the third frame 40 by screws. is, the rotation shaft 3 of the motor 2, without leaving from the engagement hole 99a of the second shaft 99, as possible out be transmitted to the blade 5 a rotation of the rotary shaft 3 of the motor 2 via the second shaft 99 .

Under these circumstances, the motor 2 is operated, and if the level of the object stored in the tank has not reached the detection level, the blade 5 causes the motor 7 to move the shaft 7. And is driven to rotate at a predetermined number of rotations.

At this time, the motor 2 that is driven to rotate in a no-load state or in a state close to it has a motor mounting plate 50 in which the rotating shaft 3 is supported by the bearing 42 and the stator is fixed, as shown by a solid line in FIG. As shown, top edge 50a
Is maintained in a horizontal state, and as shown in FIG. 7, the pressing operation piece 50b is located immediately below the stopper 40c, and as shown in FIG.
Opposing sides 43 of the pair of movable pieces 43, 44
a, 44a are in contact with both sides of the stopper 40c. At this time, the rollers 14b and 15b of the limit switches 14 and 15 are respectively connected to the convex portions 45a and 45b.
It is maintained on the flat top of the car.

When the level of the measured object reaches the detection level, the measured object becomes an obstacle to the rotation of the blade 5 and acts as a large load on the motor 2. As a result, the rotation of the rotating shaft 3 of the motor 2 is reduced, and thereafter, the rotation of the rotor of the motor 2 is stopped by applying an excessive load to the motor 2. 6, the motor mounting plate 50 is rotated in the direction A as shown in FIG. 6 (indicated by a dashed line in FIG. 6), and one of the movable pieces 43 is pulled by the coil spring (spring means) 27 by the pressing operation piece 50b. (The stator side of the motor 2 is
8 ), and displaces while rotating in the direction B shown in FIG.

Accordingly, the limit switch ( switch
Each roller 14a of the switch means) 14, 15, 1
5b convex portion 45a, and displaced from the flat portion of 45b in the foot direction (indicated by the dashed line in FIG. 6, 7), to displace the switch actuating piece 14 c, 15 c of the limit switch 14, 15 upwardly, by for varying the oFF state of both of the limit switches 14 and 15 from the on state, Sunawa
The coil spring (spring means) 27
When the stator side of the motor 2 rotates by a predetermined angle or more, the external circuit detects that the measured object has reached a predetermined level.

[0034]

As described above, according to the present invention,
Since it becomes very easy to replace only the motor, it is possible to significantly reduce the maintenance cost for the user.

[Brief description of the drawings]

FIG. 1 is an explanatory side view of a rotary level detecting device for explaining an embodiment according to the present invention.

FIG. 2 is an explanatory front view of the rotary level detecting device in FIG. 1;

FIG. 3 is a side sectional view of a main part of the rotary level detecting device shown in FIG. 1;

FIG. 4 is an explanatory diagram viewed from a direction in which a rotation shaft 3 of a motor 2 in FIG. 1 does not protrude.

FIG. 5 is an explanatory view of a main part of the rotary level detecting device of FIG. 1 as viewed from the rear.

FIG. 6 is an operation explanatory view showing an operation state of the motor mounting plate 50 when the blade 5 is rotating normally and when a large load is applied.

7 is an explanatory diagram showing a state in which rollers 14b and 15b of limit switches 14 and 15 provided on a motor mounting plate 50 are stopped at the top of a convex portion 45b of a switch operating member 45. FIG.

FIG. 8 is an explanatory diagram when a large load acts on the rotating shaft 3 of the motor 2 to operate the movable piece 43.

FIG. 9 is a structural explanatory view showing how a rotating shaft of the motor 2 and a second shaft 99 are engaged.

FIG. 10 is an explanatory sectional view of a conventional rotary level detecting device.

FIG. 11 is an explanatory side view showing an entire conventional rotary drive device (connected to a shaft).

FIG. 12 is an operation explanatory diagram when the entire rotary drive device of FIG. 11 is viewed from the front.

FIG. 13 is a structural explanatory view when the entire rotary drive device of FIG. 11 is viewed from the rear.

FIG. 14 is an explanatory side sectional view of a main part of FIG. 11;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 rotary type level detector 2 motor 3 rotary shaft 4 joint 5 blade 7,99 shaft 10 case 11 bearing 12 rotary drive 13,20 first and second frame 14,15 switch means ( limit switch ) 14a, 15a operation Knobs 14b, 15b Rollers 14c, 15c Actuating piece 16 Post 17, 22, 42 Bearing 24 Column-shaped pressing member 25 Column-shaped boss 26 Mounting piece 27 Spring means ( coil spring ) 28 Terminal board mounting plate 29 Terminal board 31 Lead wire outlet 32 Cap 33 Sealing member 40 Mounting means (third frame) 40c Stopper 40d Hole 43, 44 Movable piece 45 Switch operating member 50 Movable plate ( motor mounting plate ) 50a Upper edge 50b Pressing piece 51 Boss 90 hole 91 Slot

Claims (1)

(57) [Claims] 1. A mounting means provided with a bearing for supporting a rotating shaft of a motor, and disposed between the mounting means and the motor, rotatably mounted on a bearing provided on the mounting means,
Fixed mounting with easy removal of the stator side of the motor
A movable plate which is fixed by means, when an excessive load is applied to the rotation shaft of the motor, a spring means for pulling the stator side of the motor in the rotation direction of the rotating shaft of the motor, the spring force of the spring means A switch means for detecting when the stator side of the motor rotates a predetermined angle or more against the motor.