JP7148429B2 - waterproof motor - Google Patents

Description

The present invention relates to a waterproof motor.

Patent Document 1 discloses a mixed flow pump in which a waterproof motor is arranged inside a pump casing. A water-resistant motor includes a motor casing and an output shaft having a connecting end protruding from the motor casing, and an impeller is connected to the connecting end. The inside of the motor casing is divided into a shaft sealing chamber located on the impeller side and a mechanical chamber located on the opposite side of the shaft sealing chamber from the impeller.

Japanese Unexamined Patent Application Publication No. 2012-26308

In the waterproof motor disclosed in Patent Document 1, a mechanical seal seals between the motor casing and the output shaft in the shaft sealing chamber to prevent water from entering the machine chamber. However, a waterproof motor using a mechanical seal has a complicated structure and high cost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a water-resistant motor that can ensure sealing performance with a simple configuration without using a mechanical seal and that can be reduced in cost.

According to one aspect of the present invention, an output shaft having a base end arranged inside a motor casing and a connecting end projecting to the outside of the motor casing; A sliding type first seal member attached to the motor casing, and a buffer space formed in the motor casing so as to be positioned on the base end side of the first seal member , wherein the buffer space is , a partition wall extending in a direction intersecting the output shaft, an outer peripheral wall projecting from the partition wall toward the connecting end, a bottom wall projecting from the outer peripheral wall toward the output shaft, and the output shaft The bottom wall includes a tubular portion positioned on the connection end side of the bottom wall and surrounding the output shaft, and a tubular portion continuous with the end portion of the tubular portion on the bottom wall side. and a widening portion that widens toward the bottom wall, the first sealing member is attached to the tubular portion, and the buffer space of the first sealing member on the output shaft On the side is a flange portion having an outer diameter greater than the inner diameter of the tubular portion, surrounded by the flared portion and adjacent to the bottom wall, with a labyrinth between the bottom wall and the flange portion. Provided is a waterproof motor with a seal .

According to this waterproof motor, since the first sliding seal member that contacts the output shaft is used, the structure can be simplified and the manufacturing cost can be reduced as compared with the case where a mechanical seal is used. . Further, when the sealing performance of the first seal member cannot be ensured due to deterioration (wear) or the like, the buffer space formed on the base end side of the first seal member (that is, on the side of the machine chamber) can be used as a base rather than this buffer space. It is possible to prevent water from entering the edge. When this water-resistant motor is used in a drainage pump, it is possible to ensure operation even when it is unintentionally submerged in water, so the reliability of the drainage pump can be improved. Moreover, since the flange portion adjacent to the bottom wall is provided on the buffer space side of the first seal member on the output shaft, and the labyrinth seal portion is formed between the bottom wall and the flange portion, it is effective to prevent water from entering the buffer space. Since it can be effectively suppressed, the sealing performance can be improved.

A pair of the first seal members are attached along the output shaft with a gap therebetween, and a lubricant is filled between them. According to this aspect, it is possible to realize a dry seal without water injection while suppressing wear of the first seal member in a steady state.

The output shaft has a wall portion that is provided in the cylindrical portion so as to be positioned on the connecting end side of the first seal member and protrudes toward the output shaft, and a sliding contact portion that contacts the wall portion. and a sliding second seal member attached to the. According to this aspect, the ingress of water into the motor casing can be effectively suppressed, so that the sealing performance can be improved. Further, when the water-resistant motor is used as the water discharge motor, the second seal member can prevent coarse dust from entering, so deterioration (wear) of the first seal member can be suppressed.

A sliding third sealing member having a sliding contact portion that contacts the bottom wall and attached to the output shaft is further provided. According to this aspect, it is possible to effectively suppress the ingress of water into the buffer space, so that the sealing performance can be improved.

A viewing window having translucency is provided on the outer peripheral wall. According to this aspect, it is possible to determine the deterioration state of the first seal member by checking the amount of water that has entered the buffer space. Further, by replacing the first seal member as necessary, the soundness of the shaft sealing portion of the waterproof motor can be ensured.

It further comprises a sensor for detecting the water level in the buffer space, a compressor for supplying air to the buffer space, and a controller for controlling the compressor based on the detection result of the sensor. According to this aspect, by driving the compressor, the water in the buffer space can be reversed by the air pressure and automatically discharged to the connecting end side. Therefore, it is possible to reliably prevent water from entering from the buffer space to the base end side.

Since the water-resistant motor of the present invention includes the sliding first seal member and the buffer space, it is possible to ensure sealing performance with a simpler configuration and reduce the manufacturing cost, as compared with the case where a mechanical seal is used.

1 is a schematic diagram of a vertical shaft pump using a waterproof motor according to an embodiment of the present invention; FIG. FIG. 2 is a cross-sectional view showing the shaft sealing structure of the waterproof motor of the first embodiment; Sectional drawing which expanded a part of FIG. Sectional drawing which shows the shaft sealing structure of the waterproof motor of 2nd Embodiment.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a waterproof motor 30 according to a first embodiment of the present invention used in a vertical shaft pump (drainage pump) 10. As shown in FIG. The waterproof motor 30 is an electric driving means that can continue to operate even if it is submerged in water.

As shown in FIG. 1, the vertical shaft pump 10 includes a pump casing 12, a rotary shaft 18, and an impeller 20, and is driven by a waterproof motor 30 to drain rainwater and the like that flowed into the water suction tank 1 downstream.

The pump casing 12 is attached to the installation floor 2 covering the upper part of the suction tank 1 . The pump casing 12 includes a pumping pipe 13 arranged in the water suction tank 1 so as to extend in the vertical direction, and a bend pipe 15 arranged on the installation floor 2 . The pumping pipe 13 has a straight tubular shape as a whole, and includes a bearing casing 14 on the side of the suction port 13a at the lower end. The bend pipe 15 is generally L-shaped and includes a vertically extending vertical pipe portion (first pipe portion) 15a and a horizontally extending horizontal pipe portion (second pipe portion) 15b.

The lower end of the vertical pipe portion 15a is connected to the upper end of the pumping pipe 13 in a watertight manner. The upper end of the vertical tube portion 15a is an opening 15c for mounting the waterproof motor 30 thereon. The opening 15c of the present embodiment has a circular shape that is approximately the same height as the upper top of the horizontal pipe portion 15b, and has an inner diameter that is substantially the same as the inner diameter of the pumping pipe 13. As shown in FIG. A water pipe (not shown) for discharging water downstream is connected to the opening (outlet) of the horizontal pipe portion 15b located on the right side in FIG. The configuration of the bend pipe 15 including the opening 15c can be changed as required.

The rotating shaft 18 is arranged to extend vertically along the axis of the pumping pipe 13 . The upper end side of the rotating shaft 18 is rotatably supported by an underwater bearing 19A arranged at the upper end of the pumping pipe 13 . A lower end side of the rotating shaft 18 penetrates the bearing casing 14 and is rotatably supported by a water bearing 19B arranged in the bearing casing 14 . The impeller 20 is attached to the lower end of the rotating shaft 18 projecting downward from the bearing casing 14 .

The water-resistant motor 30 is attached to the opening 15c of the bend pipe 15 in a watertight manner. An output shaft 33 of the waterproof motor 30 protrudes into the casing 12 and is connected to the upper end of the rotating shaft 18 by a coupling 22 . By driving the waterproof motor 30 to rotate the rotary shaft 18 integrally with the output shaft 33, the impeller 20 is rotated integrally with the rotary shaft 18, and the water in the suction tank 1 is drained downstream through the pump casing 12. .

(First embodiment)
Continuing to refer to FIG. 1 , the waterproof motor 30 includes a motor casing 32 watertightly attached to the opening 15 c of the bend pipe 15 and an output shaft 33 projecting from the motor casing 32 .

The motor casing 32 may be attached directly to the pump casing 12, or may be attached to the pump casing 12 via a partition plate (not shown). The output shaft 33 has a base end (not shown) positioned on the upper side in FIG. 1 and a connecting end 33a positioned on the lower side in FIG. is arranged inside the pump casing 12 (outside the motor casing 32).

Referring also to FIG. 2, the motor casing 32 includes a cylindrical casing body 35 with a closed upper end. The casing main body 35 has an annular flange 35a fixed to the pump casing 12 (opening 15c). A partition wall 36 extending in a direction intersecting the output shaft 33 (radial direction of the motor casing 32) is provided in the casing main body 35 so as to be positioned on the flange 35a side.

The inner end of the partition wall 36 in the radial direction is spaced apart from the output shaft 33, and a cylindrical portion 36a extending along the output shaft 33 is formed at the inner end. A ball bearing 37 that rotatably supports the output shaft 33 is arranged between the cylindrical portion 36 a and the output shaft 33 . An upper cover 38 closes the space between the upper portion of the cylindrical portion 36 a and the output shaft 33 , and a lower cover 39 closes the space between the lower portion of the cylindrical portion 36 a and the output shaft 33 . A seal member 40 is attached to the output shaft 33 so as to be positioned between the ball bearing 37 and the lower cover 39 .

The interior of the motor casing 32 is partitioned by the partition wall 36 into a machine chamber 42 located on the base end side of the output shaft 33 and a shaft sealing chamber 43 located on the connecting end 33 a side of the output shaft 33 . The mechanical chamber 42 is filled with air and liquid-tightly sealed (dry type) by a shaft sealing device 45 arranged in the shaft sealing chamber 43 .

A well-known rotor and stator (not shown) are arranged in the machine room 42 . The rotor is attached to the output shaft 33, and the stator is attached to the casing main body 35 so as to be positioned on the outer circumference of the rotor. As the rotor rotates with respect to the stator due to energization, the output shaft 33 rotates together.

The shaft sealing device 45 includes a pair of seal members 58, a buffer space 62, a labyrinth seal portion 65, and two seal members 70A and 70B. These are provided from the pump casing 12 side toward the machine chamber 42 in the order of the seal member 70A, the pair of seal members 58, the labyrinth seal portion 65, the seal member 70B, and the buffer space 62. In the following description, the pump casing 12 side may be called the upstream side, and the machine room 42 side may be called the downstream side.

Specifically, the shaft sealing device 45 includes a receiving plate member (fixed member) 47 for forming the buffer space 62, a flange member (rotating member) 50 for forming the labyrinth seal portion 65, a seal member (first seal A cylindrical member (cover member) 52 for arranging a member) 58 and a sleeve 55 with which the sealing member 58 is in sliding contact.

The receiving plate member 47 is attached to the motor casing 32 so as to be adjacent to the partition wall 36 on the connecting end 33 a side of the output shaft 33 . The receiving plate member 47 includes an outer peripheral wall 47a protruding upstream (connecting end 33a side) from the partition wall 36 and a bottom wall 47b protruding toward the output shaft 33 from the outer peripheral wall 47a. The outer peripheral wall 47 a has a cylindrical shape around the output shaft 33 and is fixed to the partition wall 36 . A packing 48 seals between the outer peripheral wall 47 a and the partition wall 36 . The bottom wall 47 b protrudes radially inward from the upstream end of the outer peripheral wall 47 a , and its inner end is positioned near the output shaft 33 . A clearance is provided between the bottom wall 47b and the output shaft 33 so that they do not interfere with each other when the output shaft 33 rotates.

The flange member 50 is attached to the output shaft 33 so as to be adjacent to the bottom wall 47b on the connecting end 33a side of the output shaft 33 . The flange member 50 has a cylindrical mounting portion 50a that is mounted immovably on the output shaft 33 by a set bolt (not shown), and projects radially outward from the mounting portion 50a centering on the output shaft 33. A disk-shaped flange portion 50b is provided. The flange portion 50b is arranged on the side of the connecting end 33a with respect to the bottom wall 47b, extends parallel to and adjacent to the bottom wall 47b, and rotates together with the rotation of the output shaft 33. As shown in FIG.

The tubular member 52 is attached to the bottom wall 47b so as to be adjacent to the bottom wall 47b on the connecting end 33a side of the output shaft 33 . That is, the cylindrical member 52 does not rotate integrally with the output shaft 33 . The cylindrical member 52 has a cylindrical shape centered on the output shaft 33, and includes an enlarged portion 52a covering the outer side of the flange portion 50b in the radial direction, and a tubular portion 52b projecting upstream from the enlarged portion 52a. Prepare. The expanded portion 52a has a conical cylindrical shape whose diameter gradually decreases from the bottom wall 47b toward the upstream side, and is fixed to the bottom wall 47b. A packing 53 seals between the expanded portion 52a and the bottom wall 47b. The cylindrical portion 52b has a cylindrical shape centered on the output shaft 33, and has an inner diameter smaller than the outer diameter of the flange portion 50b. It is formed with a dimension that can secure a space of

The sleeve 55 is attached to the output shaft 33 by a set bolt (not shown) so as to be positioned inside the cylindrical portion 52b so as not to move relative to the output shaft 33 . The upper end of the downstream sleeve 55 protrudes from the tubular portion 52b into the expanding portion 52a and is adjacent to the mounting portion 50a. The lower end of the upstream sleeve 55 protrudes downstream from the tubular portion 52b.

Referring to FIG. 3 in conjunction with FIG. 2, the pair of seal members 58 are mounted inside the tubular portion 52b (motor casing 32), respectively, and spaced apart along the output shaft 33. As shown in FIG. The seal member 58 is a sliding lip seal made of a Teflon (registered trademark) material, and has a mounting portion 58a and a sliding contact portion 58b. The attachment portion 58a is attached to the inner peripheral surface of the tubular portion 52b. A packing 59 seals between the mounting portion 58a and the cylindrical portion 52b. The sliding contact portion 58 b is elastically deformable, contacts the outer periphery of the sleeve 55 (output shaft 33 ), and comes into sliding contact with the sleeve 55 as the output shaft 33 rotates.

A hard portion 56 having a hardness higher than that of the seal member 58 is provided in a portion of the sleeve 55 with which the seal member 58 slides. The sleeve 55 is made of metal, and the hard portion 56 is formed by spraying cemented carbide, which is harder than the sleeve 55 . More specifically, the Vickers hardness Hv of the hard portion 56 is preferably 1000 or more (Hv>1000).

In order to suppress wear of the sliding contact portion 58b, a space defined by the pair of seal members 58, the inner peripheral surface of the tubular portion 52b, and the outer peripheral surface of the sleeve 55 is filled with a biodegradable lubricant (grease). 60 is filled. A passage 52c for replenishing the lubricant 60 is provided in the cylindrical member 52 so as to communicate with the filling space of the lubricant 60 . In order to secure the strength when the filling nozzle is connected, the tubular portion 52b is provided with a protrusion 52d that protrudes radially outward in a part of the circumferential direction. 52c is provided. Lubricant 60 is periodically replenished during maintenance. During normal operation, the outlet of the passage 52c is sealed with a bolt (not shown).

The buffer space 62 is formed in the motor casing 32 so as to be positioned on the machine chamber 42 side (base end side) of the seal member 58 . The buffer space 62 is defined by the partition wall 36 of the casing body 35 , the outer peripheral wall 47 a of the receiving plate member 47 , the bottom wall 47 b of the receiving plate member 47 , and the outer peripheral surface of the output shaft 33 . The buffer space 62 and the outside of the motor casing 32 (inside the pump casing 12) are liquid-tightly sealed by the pair of seal members 58 and the two seal members 70A and 70B. will not be flooded. In the event of unintended water ingress, including deterioration of the pair of seal members 58 and the two seal members 70A and 70B, the buffer space 62 retains water to prevent water from entering the machine chamber 42 .

The volume of the buffer space 62 varies depending on the diameter of the output shaft 33 (that is, the gap area formed around the output shaft 33). It is preferable to set it to 0.1D (liter) or less, and in this embodiment, it is set to 0.04D (liter). If the capacity is made too small, the buffer space 62 will soon be filled with water, making it impossible to prevent water from entering the machine room 42 . Although it is preferable that the volume is as large as possible, if the volume is excessively large, the waterproof motor 30 itself becomes large. Therefore, it is preferable to set the volume of the buffer space 62 within the range defined above.

In order to check the amount of water stored in the buffer space 62, the outer peripheral wall 47a is provided with a viewing window 63 having translucency. Here, having translucency means having a light transmittance to the extent that whether or not water is accumulated in the buffer space 62 can be visually confirmed from the outside. The tubular member 52 including the outer peripheral wall 47a is made of an opaque material (such as metal), and the viewing window 63 is made of a colorless transparent or colored transparent material (such as resin).

The labyrinth seal portion 65 is formed between the bottom wall 47 b of the receiving plate member 47 and the flange portion 50 b of the flange member 50 . The labyrinth seal portion 65 includes an annular groove 66 provided in the bottom wall 47b and an annular protrusion 67 provided in the flange portion 50b. A plurality (three in this embodiment) of the concave groove 66 and the convex portion 67 are provided at intervals in the radial direction around the output shaft 33 . The plurality of grooves 66 and projections 67 are concentric with the output shaft 33 as the center. The rotation of the output shaft 33 rotates the convex portion 67 and does not rotate the concave groove 66 . Between the concave groove 66 and the convex portion 67, there is a clearance to the extent that they do not interfere with each other due to rotation. The concave groove 66 may be formed in the flange portion 50b and the convex portion 67 may be formed in the bottom wall 47b.

The seal members 70A and 70B are attached to the output shaft 33 and rotate together with the output shaft 33 . Each of the seal members 70A and 70B is a sliding V-ring made of rubber, and includes an attachment portion 70a attached to the output shaft 33 and a sliding contact portion 70b for sealing.

The seal member 70A is arranged on the upstream side of the seal member 58 and prevents entry of water and dust from the upstream side (inside the pump casing 12) to the downstream side (buffer space 62 side). A wall portion 52e projecting toward the output shaft 33 is formed on the upstream side of the seal member 58 in the cylindrical portion 52b. The attachment portion 70a of the seal member 70A is attached to the sleeve 55 so that the sliding contact portion 70b is in contact with the wall portion 52e.

The seal member 70B is arranged downstream of the labyrinth seal portion 65 so as to be positioned within the buffer space 62 . The attachment portion 70a of the seal member 70B is attached to the output shaft 33 so that the sliding contact portion 70b is in contact with the upper surface of the bottom wall 47b of the receiving plate member 47. As shown in FIG.

When the operation of the vertical shaft pump 10 is started by driving the waterproof motor 30 constructed in this way, the water sucked up from the water discharge pipe 13 fills up to the opening 15c. If a partition plate is interposed between the opening 15c and the motor casing 32 and there is no liquid leakage, water will not enter the motor casing 32 (shaft seal chamber 43). , water may enter the motor casing 32 (shaft seal chamber 43). Also, if there is no partition plate between the opening 15c and the motor casing 32, water enters the motor casing 32 (shaft sealing chamber 43).

As shown in FIG. 2, water that has entered the shaft sealing chamber 43 first passes through the outer peripheral wall of the casing body 35, the upstream side of the partition wall 36, the radially outer side of the receiving plate member 47, the radially outer side of the cylindrical member 52, And the space on the upstream side of the wall portion 52e of the cylindrical member 52 is filled. Further, water ingress from the wall portion 52e of the cylindrical member 52 to the downstream side is blocked by the sealing member 70A. At this time, coarse dust contained in the water is also blocked by the sealing member 70A.

As a result, the downstream side from the wall portion 52e in the cylindrical member 52 including the buffer space 62 is in a dry sealed state without water. In a dry seal without water injection, deterioration of the sliding portion (seal member) is likely to progress. However, since a pair of seal members 58 are provided and the lubricant 60 is filled between them, wear of the seal members 58 is effectively suppressed.

When the seal member 70A wears due to sliding contact with the wall portion 52e and the sealing performance cannot be secured, water on the upstream side of the wall portion 52e flows between the wall portion 52e and the seal member 70A toward the seal member 58. invade into This water is blocked by a pair of seal members 58 .

When the pair of seal members 58 wear out due to the sliding contact with the sleeve 55 and the sealing property cannot be ensured, water flows between the sleeve 55 and the seal members 58 and enters the expanded portion 52a. This water is mostly blocked by the labyrinth seal portion 65 .

In the labyrinth seal portion 65 , the flow to the downstream side can be gradually reduced by the plurality of grooves 66 and projections 67 , but it is difficult to completely block the flow. In addition, it infiltrates downstream little by little. This water is blocked by the seal member 70B.

When the sealing member 70B wears due to sliding contact with the bottom wall 47b and the sealing property cannot be ensured, the liquid enters the buffer space 62 through the space between the sealing member 70B and the bottom wall 47b and is accumulated.

In this way, the seal member 70A, the pair of seal members 58, the labyrinth seal portion 65, the seal member 70B, and the buffer space 62 can prevent water from entering the machine room 42 in this order. can be effectively suppressed. Therefore, when the water-resistant motor 30 is used for the vertical shaft pump 10, the reliability of the vertical shaft pump 10 can be improved because the operation can be ensured when the vertical shaft pump 10 is unintentionally submerged in water.

During maintenance, an operator checks the amount of water stored in the buffer space 62 through the viewing window 63. - 特許庁The operator can judge that the deterioration of the seal members 58, 70A, 70B is small when no water is accumulated in the buffer space 62, and the seal members 58, 70A are not deteriorated when much water is accumulated in the buffer space 62. , 70B are more deteriorated. Then, when there is much deterioration, the seal members 58, 70A, 70B are replaced.

The waterproof motor 30 configured in this manner has the following features.

Since the sliding type seal member 58 in contact with the output shaft 33 is used, the structure can be simplified and the manufacturing cost can be reduced as compared with the case of using a mechanical seal. Further, when the sealing performance of the seal member 58 cannot be ensured due to deterioration (wear) or the like, the buffer space 62 on the downstream side of the seal member 58 can prevent water from entering the downstream side of the buffer space 62 .

A pair of seal members 58 are attached along the output shaft 33 with a gap therebetween, and a lubricant 60 is filled between them. Therefore, in a steady state, dry sealing without water injection is performed while suppressing wear of the seal members 58. can be realized.

Since the labyrinth seal portion 65 is formed between the bottom wall 47b that defines the buffer space 62 and the flange portion 50b, the ingress of water into the buffer space 62 can be further suppressed. Since the seal member 70A is arranged on the upstream side of the seal member 58 and the seal member 70B is arranged on the downstream side of the seal member 58, the ingress of water into the buffer space 62 can be suppressed more effectively. Therefore, the sealing performance of the shaft sealing device 45 can be effectively improved. In addition, since the seal member 70A can prevent coarse dust from entering, deterioration (wear) of the seal member 58 can be suppressed.

Since a viewing window 63 is provided in the outer peripheral wall 47a that defines the buffer space 62, the amount of water that has entered the buffer space 62 can be confirmed. Further, the deterioration state of the seal member 58 and the seal members 70A and 70B can be determined from the amount of water in the buffer space 62. FIG. Therefore, by replacing the seal member 58 and the seal members 70A and 70B as necessary, the soundness of the shaft sealing portion of the waterproof motor 30 can be ensured.

(Second embodiment)
FIG. 4 shows a waterproof motor 30 of the second embodiment. The second embodiment is different from the first embodiment in that a drainage mechanism 75 for discharging water accumulated in the buffer space 62 is provided. Specifically, the drainage mechanism 75 includes a sensor 76 for detecting the water level in the buffer space 62, a compressor 77 for supplying air to the buffer space 62, and a control unit for controlling the compressor 77 based on the detection result of the sensor 76. 84. Although the waterproof motor 30 of the second embodiment has the viewing window 63 as in the first embodiment, the viewing window 63 may be omitted.

The sensor 76 is arranged on the partition wall 36 so as to be positioned within the buffer space 62 and is electrically connected to the controller 84 . The sensor 76 detects the water level in the buffer space 62 and outputs a signal according to the detection result to the control section 84 . A well-known level sensor can be used as such a sensor 76, and its type may be any of a float type, an electrode type, an optical type, an ultrasonic type, and the like. That is, the sensor 76 may be configured to detect that the limit water level (capacity) has been reached, or may be configured to detect the actual reservoir water level at any time.

The compressor 77 is arranged outside the motor casing 32 (on the installation floor 2 ) and electrically connected to the controller 84 . The tip of the air supply pipe 78 connected to the discharge port of the compressor 77 passes through the receiving plate member 47 and is arranged in the buffer space 62 . A pressure tank 79 , a check valve 80 and an on-off valve 81 are interposed in the air supply pipe 78 . The pressure tank 79 stores the compressed air discharged from the compressor 77 up to a predetermined pressure. The check valve 80 allows air to flow from the compressor 77 toward the pressure tank 79 and prevents air from flowing in the opposite direction. The on-off valve 81 is electrically connected to the control unit 84, and switches the pressure tank 79 and the buffer space 62 between a communication state and a disconnection state according to an open/close signal from the control unit 84. FIG.

In this embodiment, a branch pipe 82 is branched and connected to the air supply pipe 78 so as to be positioned downstream of the pressure tank 79 (that is, on the side opposite to the compressor 77). The tip of the branch pipe 82 passes through a receiving plate member of a waterproof motor having the same structure as that of the waterproof motor 30 and is arranged in the buffer space. An on-off valve 83 similar to the on-off valve 81 is interposed in the branch pipe 82 , and the on-off valve 83 is electrically connected to the control section 84 . The number of branch pipes including on-off valves is not limited to one, and may be two or more.

The control unit 84 includes a storage unit (memory) that stores a program for controlling the drainage mechanism 75, threshold values and judgment values used in the program, and is configured to be able to individually control two or more waterproof motors 30. there is A personal computer, for example, can be used as the control unit 84 . The controller 84 may also have the function of controlling the waterproof motor 30 .

Detection data corresponding to the water level in the buffer space 62 detected by the sensor 76 is input to the control unit 84 at any time or periodically. When the control unit 84 determines that the water level in the buffer space 62 is below the set water level based on the detection result input from the sensor 76, the control unit 84 maintains the compressor 77 in a stopped state and the on-off valve 81 in a closed state. . On the other hand, when the controller 84 determines that the buffer space 62 contains water equal to or higher than the set water level, it drives the compressor 77 and opens the on-off valve 81 to supply air into the buffer space 62 (drainage). process).

In this drainage treatment, the supplied air accumulates in the upper portion of the buffer space 62, and this air pushes the water accumulated in the buffer space 62 downward. As a result, the water in the buffer space 62 passes between the seal member 70B and the bottom wall 47b, between the labyrinth seal portion 65, between the seal member 58 and the sleeve 55, and between the seal member 70A and the wall portion 52e. (pump casing 12).

Thus, in the waterproof motor 30 of the second embodiment, by driving the compressor 77, the air pressure causes the water in the buffer space 62 to flow backward to the upstream side, and can be automatically discharged to the outside (connection end 33a side). Therefore, it is possible to reliably prevent water from entering the machine room 42 (base end side) from the buffer space 62 .

It should be noted that the waterproof motor 30 of the present invention is not limited to the configuration of the above embodiment, and various modifications are possible.

For example, the labyrinth seal portion 65 including the tubular member 52 may not be formed. Also, at least one of the two seal members 70A and 70B may not be arranged. Both the viewing window 63 and the drainage mechanism 75 may be omitted.

The seal member 58 may be attached to the output shaft 33 so as to be positioned on the upstream side (connection end 33a side) of the wall portion 52e. The seal member 70A may be arranged adjacent to the machine room 42 side (base end side) of the bottom wall 47b. The flange portion 50b for forming the labyrinth seal portion 65 may be provided adjacent to the machine chamber 42 side (base end side) of the bottom wall 47b. The member for providing the walls (that is, the partition wall 36, the outer peripheral wall 47a, and the bottom wall 47b) for demarcating the buffer space 62 and the position for forming the buffer space 62 can be changed as necessary.

The waterproof motor 30 may be used in mechanisms other than the vertical shaft pump 10 (for example, a submersible mixer).

1 suction tank 2 installation floor 10 vertical shaft pump 12 pump casing 13 pumping pipe 13a suction port 14 bearing casing 15 bend pipe 15a vertical pipe portion 15b horizontal pipe portion 15c opening 18 rotary shaft 19A, 19B underwater bearing 20 impeller 22 coupling 30 water resistance Motor 32 Motor casing 33 Output shaft 33a Connection end 35 Casing main body 35a Flange 36 Partition wall 36a Cylindrical portion 37 Ball bearing 38 Upper cover 39 Lower cover 40 Seal member 42 Machine room (base end side of output shaft)
43 shaft sealing chamber 45 shaft sealing device 47 receiving plate member 47a outer peripheral wall 47b bottom wall 48 packing 50 flange member 50a mounting portion 50b flange portion 52 tubular member 52a expanding portion 52b tubular portion 52c passage 52d projecting portion 52e wall portion 53 packing 55 sleeve 56 hard portion 58 seal member 58a mounting portion 58b sliding contact portion 59 packing 60 lubricant 62 buffer space 63 viewing window 65 labyrinth seal portion 66 concave groove 67 convex portion 70A, 70B sealing member 70a mounting portion 70b sliding contact portion 75 drainage Mechanism 76 Sensor 77 Compressor 78 Air supply pipe 79 Pressure tank 80 Check valve 81 On-off valve 82 Branch pipe 83 On-off valve 84 Control unit

Claims (6)

an output shaft having a base end arranged inside a motor casing and a connecting end projecting outside the motor casing;
a slidable first seal member attached to the motor casing and having a sliding contact portion in contact with the outer circumference of the output shaft;
a buffer space formed in the motor casing so as to be positioned on the base end side of the first seal member ;
The buffer space includes a partition wall extending in a direction intersecting the output shaft, an outer peripheral wall projecting from the partition wall toward the connecting end, a bottom wall projecting from the outer peripheral wall toward the output shaft, and the defined by the output shaft and
The bottom wall includes a cylindrical portion positioned on the connection end side of the bottom wall and surrounding the output shaft; A cover member having a widening portion that widens toward the wall is attached,
The first sealing member is attached to the tubular portion,
A flange portion having an outer diameter larger than the inner diameter of the cylindrical portion, surrounded by the expanded portion, and adjacent to the bottom wall is provided on the output shaft on the buffer space side of the first seal member. be
A waterproof motor , wherein a labyrinth seal portion is formed between the bottom wall and the flange portion . 2. The waterproof motor according to claim 1, wherein a pair of said first seal members are attached along said output shaft with a gap therebetween, and a lubricant is filled between them. a wall portion provided in the cylindrical portion so as to be positioned on the connecting end side of the first seal member and protruding toward the output shaft;
3. The waterproof motor according to claim 1 , further comprising: a sliding type second seal member attached to said output shaft and having a sliding contact portion that contacts said wall portion. 4. The waterproof motor according to any one of claims 1 to 3 , further comprising a slidable third seal member attached to the output shaft and having a sliding contact portion in contact with the bottom wall. 5. The waterproof motor according to any one of claims 1 to 4 , wherein the outer peripheral wall is provided with a translucent viewing window. a sensor that detects the water level in the buffer space;
a compressor for supplying air to the buffer space;
The waterproof motor according to any one of claims 1 to 5 , further comprising: a control section that controls the compressor based on the detection result of the sensor.

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