JP7020175B2 - Local cleaning equipment - Google Patents

Description

The present invention relates to a local cleaning device having a nozzle that can move forward and backward by rotating a rotating body.

Conventionally, this type of local cleaning device has a valve device main body including a substantially Western-shaped valve operating body, a cylinder that rotates inside the valve operating body, and a nozzle hole capable of ejecting cleaning water. A nozzle body that slides inside the cylinder, a drive gear for external teeth provided on the outer peripheral portion of the rear end of the cylinder, and an electric motor that rotates the drive gear have been proposed (see, for example, Patent Document 1). ). In this local cleaning device, a spiral concave groove (spiral groove) is formed on the inner wall of the cylinder, and a protrusion for sliding the spiral concave groove is provided on the outer peripheral portion of the nozzle body, and the cylinder is rotated by an electric motor. By driving, the nozzle body can be moved forward and backward with respect to the cylinder.

Japanese Unexamined Patent Publication No. 2001-271403

In the above-mentioned local cleaning device, the pitches of the spiral grooves are formed at equal intervals. If the pitch of the spiral groove is widened, the amount of advancement and retreat of the nozzle increases with respect to the rotation of the cylinder, which makes it difficult to position the nozzle at the advance position or the accommodation position. On the other hand, if the pitch of the spiral groove is narrowed, the amount of advancement and retreat of the nozzle with respect to the rotation of the cylinder is reduced, so that the above-mentioned positioning is easy, but the moving speed of the nozzle is slowed down, and an instruction to start local cleaning is instructed. It takes a long time to actually perform local cleaning.

In the local cleaning device of the present invention, the spiral groove provided on the inner peripheral surface of the rotating body and the fitting portion provided at the rear end of the nozzle are fitted, and the nozzle moves back and forth as the rotating body rotates. The main purpose of the work is to improve the moving speed when moving the nozzle forward and backward and the positioning accuracy of the nozzle at the same time.

The local cleaning device of the present invention has adopted the following means in order to achieve the above-mentioned main object.

The local cleaning device of the present invention is
It is a local cleaning device that cleans the local part of the human body.
A cylindrical rotating body with a spiral groove on the inner peripheral surface,
A rotating gear provided on the rotating body coaxially with the rotating body, and
A motor that rotates the rotary gear and
It is provided inside the rotating body, has a spout at the tip capable of ejecting washing water, and has a fitting portion that fits with the spiral groove at the rear end, and is rearward as the rotating body rotates. A nozzle that can move forward and backward along the axial direction of the rotating body between the accommodation position and the forward advance position.
Equipped with
The spiral groove is formed so that the distance between adjacent grooves changes in the axial direction of the rotating body.
The gist is that.

In the local cleaning device of the present invention, the spiral groove provided on the inner peripheral surface of the rotating body and the fitting portion provided at the rear end of the nozzle are fitted, and the nozzle advances and retreats as the rotating body rotates. In a moving object, spiral grooves are formed so that the distance between adjacent grooves changes in the axial direction of the rotating body. By narrowing the space between the spiral grooves where the nozzle needs to be positioned and widening the space at other places, both the improvement of the moving speed when moving the nozzle forward and backward and the improvement of the nozzle positioning accuracy are achieved. be able to.

In such a local cleaning device of the present invention, the spiral groove may be formed so that the distance between adjacent grooves in the tip portion of the rotating body is narrower than that in the central portion. By doing so, it is possible to position the advance position of the nozzle with high accuracy while increasing the moving speed until the nozzle approaches the advance / retreat position (cleaning position).

Further, in the local cleaning device of the present invention, the spiral groove may be formed so that the distance between adjacent grooves in the rear end portion of the rotating body is narrower than that in the central portion. By doing so, it is possible to position the nozzle accommodating position with high accuracy while increasing the moving speed until the nozzle approaches the accommodating position after performing local cleaning.

It is an external perspective view of the toilet bowl 1 to which the sanitary washing toilet seat device 10 including the local washing device of this embodiment is attached. FIG. 3 is an external perspective view of the nozzle unit 20 included in the local cleaning device as viewed from the front side. It is an exploded perspective view of a nozzle unit 20. It is an external perspective view of a nozzle 30. It is external perspective view of the semi-cylindrical member 41, 42 which constitutes a cylinder 40. It is a top view of the inner peripheral surface side of a semi-cylindrical member 41, 42. It is an external perspective view of the semi-cylindrical member 52 which constitutes a part of a case 50. It is external perspective view of the semi-cylindrical member 141, 142 of a modification.

A mode for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is an external perspective view of a toilet bowl 1 to which a sanitary cleaning toilet seat device 10 including the local cleaning device of the present embodiment is attached, and FIG. 2 is an external perspective view of a nozzle unit 20 included in the local cleaning device. 3 is an exploded perspective view of the nozzle unit 20. The toilet bowl 1 is a Western-style toilet bowl, and a sanitary washing toilet seat device 10 is installed on the upper surface of the toilet bowl 1. As shown in FIG. 1, the sanitary washing toilet seat device 10 is mounted on the toilet seat device main body 12 installed behind the toilet bowl 1, the toilet seat 14 rotatably supported by the toilet seat device main body 12, and the toilet seat device main body 12. It includes a toilet lid 16 that is movably supported and an operation panel 18 that is operated by the user.

The main body 12 of the toilet seat device includes a washing water flow path connected to a water supply pipe (water supply pipe), a water stop valve, a heat exchange unit, a pulsating pump for adjusting the washing strength, a nozzle unit 20 for ejecting washing water, a switching valve, and the like. It is equipped with local cleaning devices including, which are housed in a resin housing. The heat exchange unit is provided with a water tank, a heater, and a temperature sensor, and the water from the water supply pipe is converted into hot water by the heater.

Further, the toilet seat device main body 12 includes a control device (not shown) that controls the sanitary washing toilet seat device 10. The control device controls the heater, the pulsation pump, the nozzle unit 20, and the switching valve in the water tank based on the signals from the operation panel 18, the seating sensor 13 (see FIG. 1), the temperature sensor of the water tank, and the like. Although not shown, the operation panel 18 has a cleaning switch for the butt that instructs the cleaning of the butt, a cleaning switch for the bidet that instructs the cleaning of the bidet, a cleaning strength adjusting switch for adjusting the strength of the cleaning, and a cleaning position in the front-back direction. A cleaning position adjustment switch (front switch, rear switch) for adjustment, a stop switch instructing to stop cleaning, etc. are provided.

The nozzle unit 20 includes a nozzle 30, a cylinder 40, a case 50, a nozzle washer 60, a motor 24, and the like.

The nozzle 30 moves back and forth between the accommodation position (see FIG. 2A) and the cleaning position (see FIG. 2B), and is configured to be capable of ejecting cleaning water locally to the human body at the cleaning position. FIG. 4 is an external perspective view of the nozzle 30. Note that FIG. 4A shows the upper surface side of the nozzle 30, and FIG. 4B shows the lower surface side of the nozzle 30. The nozzle 30 has a cylindrical nozzle body 31 having an open rear end and two nozzle holes 31a and 31b formed at the tip of the nozzle body 31. In the present embodiment, the nozzle hole 32a is configured as a nozzle hole for cleaning the buttocks, and the nozzle hole 32b is configured as a nozzle hole for cleaning the bidet. Although not shown, two wash water flow paths are provided inside the nozzle body 31, one of which is communicated with the nozzle hole 32a and the other outlet of the wash water flow path 38 is a nozzle hole 32b. It is communicated. One ends of hoses 21 and 22, respectively, are inserted and connected to the inlets of the two wash water channels from the openings at the rear ends of the nozzle body 31, and a switching valve is connected to the other ends of the hoses 21 and 22. Further, as shown in FIG. 4, a plurality of circular (for example, four) protrusions 35 are formed on the outer peripheral surface of the rear end portion of the nozzle body 31 at equal angular intervals in the circumferential direction. Further, as shown in FIG. 4B, a guide groove 31c (recessed groove) extending in the axial direction (advancing / retreating direction) is formed between the front end portion and the rear end portion front on the lower surface side of the nozzle body 31. Has been done.

The cylinder 40 is a cylindrical rotating body having an open front end and a rear end, and has an inner diameter slightly larger than the outer diameter of the nozzle 30 so as to surround the nozzle 30. FIG. 5 is an external perspective view of the semi-cylindrical members 41 and 42 constituting the cylinder 40, and FIG. 6 is a plan view of the semi-cylindrical members 41 and 42 on the inner peripheral surface side. The cylinder 40 is formed by abutting the end faces of the two semi-cylindrical members 41 and 42 in the circumferential direction. As shown in FIGS. 3 and 5, the outer peripheral surfaces of the semi-cylindrical members 41 and 42 have a semicircular shape so as to form an annular shape with the peripheral end faces of the semi-cylindrical members 41 and 42 abutting against each other. The formed outer peripheral rib 43 is formed. Further, as shown in FIGS. 5 and 6, a plurality of inner peripheral ribs 44 extending in an inclined direction with respect to the axial direction of the cylinder 40 are formed on the inner peripheral surfaces of the semi-cylindrical members 41 and 42, respectively. The plurality of inner peripheral ribs 44 form a spiral groove 44a in which the grooves between the adjacent inner peripheral ribs 44 are spirally connected in a state where the end faces of the semi-cylindrical members 41 and 42 in the circumferential direction are abutted against each other. The spiral groove 44a is formed so that the pitch between the adjacent grooves in the front end portion and the rear end portion in the axial direction of the cylinder 40 is narrower than that in the central portion.

Further, as shown in FIGS. 3 and 5, the outer peripheral surfaces of the rear end portions of the semi-cylindrical members 41 and 42 form an annular shape in a state where the end faces of the semi-cylindrical members 41 and 42 in the circumferential direction are abutted against each other. A semicircular rotary gear 45 is provided on the surface. In the present embodiment, the rotary gear 45 is formed so as to have an outer diameter smaller than the outer diameter of the case 50 so as not to protrude from the outer diameter of the case 50 (see FIG. 2). The rotary gear 45 is meshed with a drive gear 25 attached to the rotary shaft of the motor 24, and the cylinder 40 rotates integrally with the rotary gear 45 by rotationally driving the rotary gear 45 by the motor 24. A protrusion 35 provided on the outer peripheral surface of the rear end of the nozzle 30 is fitted in the spiral groove 44a formed on the inner peripheral surface of the cylinder 40, and the protrusion 35 is formed in the nozzle 30 by rotating the cylinder 40. While moving relatively along the spiral groove 44a, it moves back and forth between the accommodation position and the advance position.

Further, in the present embodiment, the semi-cylindrical members 41 and 42 are injected by injecting a resin material into the space between the concave mold forming the outer peripheral surface and the convex mold forming the inner peripheral surface, and cooling and solidifying the resin material. It is formed by molding, and the rotary gear 45, the outer peripheral rib 43, and the inner peripheral rib 44 are integrally formed on the semi-cylindrical members 41 and 42. Further, as shown in FIG. 6, the inner peripheral ribs 44 are not formed at both ends of the inner peripheral surfaces of the semi-cylindrical members 41 and 42 in the circumferential direction, and are die-cut (convex type) during injection molding. Die-cutting) can be performed smoothly.

The case 50 is a cylindrical member having an open front end and a rear end, and has an inner diameter slightly larger than the outer diameter of the cylinder 40 so as to surround the cylinder 40 and rotatably support the cylinder 40. As shown in FIG. 3, the case 50 is formed by abutting the end faces of the two semi-cylindrical members 51 and 52 in the circumferential direction. A semicircular inner peripheral groove 53 is formed on the inner peripheral surface of the case 50 so as to form an annular shape in a state where the end faces of the two semi-cylindrical members 51 and 52 in the circumferential direction are abutted against each other. The outer peripheral rib 43 of the cylinder 40 is fitted to the 53. In the present embodiment, the inner peripheral groove 53 has a depth shallower than the height of the outer peripheral rib 43, and the cylinder 50 is rotatably supported by the case 50 with a small frictional resistance. Further, a fixing plate 52a extending in the radial direction is integrally provided on the outer peripheral surface of the rear end portion of the case 50, and the housing of the motor 24 is fixed to the fixing plate 52a.

FIG. 7 is an external perspective view of the semi-cylindrical member 52 that constitutes a part of the case 50. As shown in the figure, the semi-cylindrical member 52 on the lower surface side of the case 50 is provided with a guide rib 54 projecting upward. The guide rib 54 is formed on the tip end side of the support surface that supports the outer peripheral surface of the cylinder 40 of the case 50, and guides the advancing / retreating movement of the nozzle 31 by fitting into the guide groove 31c of the nozzle 31. This prevents the nozzle 30 from rotating with the rotation of the cylinder 40. Therefore, in the nozzle unit 20 of the present embodiment, the nozzle 30 can be formed in a cylindrical shape, dirt is less likely to adhere to the nozzle 30, and cleanliness can be further improved.

The nozzle washer 60 is attached to the upper surface of the tip of the case 50 and has a ejection hole for ejecting cleaning water toward the upper surface of the nozzle 30. One end of the hose 23 is connected to the nozzle washer 60, and a switching valve is connected to the other end of the hose 23.

The switching valve switches whether the supply destination of the washing water in the washing water flow path downstream of the pulsation pump is ejected from the two nozzle holes 31a and 31b of the nozzle 30 or the ejection holes of the nozzle washer 60. For example, it is configured as a rotary valve driven by a motor.

Next, the operation of the sanitary washing toilet seat device 10 (nozzle unit 20 of the local washing device) of the present embodiment configured in this way will be described. The control device of the sanitary washing toilet seat device 10 determines that the user is seated on the toilet seat 14 by the seating sensor 13, and the washing switch for the back of the operation panel 18 is pressed to instruct the start of the washing of the toilet. When it is determined, the motor 24 rotates the rotary gear 45 that meshes with the drive gear 25 to rotate the cylinder 40. When the cylinder 40 rotates, the plurality of protrusions 35 provided on the nozzle 30 move relatively along the spiral groove 44a formed on the inner peripheral surface of the cylinder 40, and the nozzle 30 heads toward the cleaning position for cleaning the buttocks. To advance. When the nozzle 30 reaches the cleaning position, the control device controls the switching valve (motor) so that the cleaning water from the pulsating pump is supplied to the nozzle hole 32a of the nozzle 30 via the hose 21. As a result, washing water is ejected from the nozzle hole 32a toward the anus of the human body, and the buttocks washing is started. When the control device determines that the front switch (cleaning position adjustment switch) is pressed and the change to the front of the cleaning position is instructed, the control device rotates the cylinder 40 by the motor 24 to advance the nozzle 30 by a predetermined amount. Further, when the control device determines that the rear switch (cleaning position adjustment switch) is pressed and the change to the rearward cleaning position is instructed, the motor 24 reversely rotates the cylinder 40 to retract the nozzle 30 by a predetermined amount. .. When the control device determines that the stop switch of the operation panel 18 is pressed and the stop of the buttocks washing is instructed, the control device stops the water supply to the nozzle 30. Then, the rotary gear 45 is rotated in the reverse direction by the motor 24, the nozzle 30 is retracted toward the accommodation position, and the nozzle 30 is accommodated in the cylinder 40. The control device controls the switching valve (motor) so that the cleaning water is ejected from the nozzle washer 60 toward the nozzle 30 on the way from the cleaning position to the accommodation position or when the nozzle 30 reaches the accommodation position. Clean the nozzle 30.

Further, when the control device determines that the user is seated on the toilet seat 14 by the seating sensor 13, and determines that the bidet cleaning switch on the operation panel 18 is pressed to instruct the start of bidet cleaning, the motor The cylinder 40 is rotated by 24, and the nozzle 30 is advanced toward the cleaning position for bidet cleaning. When the nozzle 30 reaches the cleaning position, the control device controls the switching valve (motor) so that the cleaning water from the pulsation pump is supplied to the nozzle hole 32b of the nozzle 30 via the hose 22. As a result, the washing water is ejected from the nozzle hole 32b toward the bidet portion of the human body, and the bidet washing is started. When the control device determines that the front switch (cleaning position adjustment switch) is pressed and the change to the front of the cleaning position is instructed, the control device rotates the cylinder 40 by the motor 24 to advance the nozzle 30 by a predetermined amount. Further, when the control device determines that the rear switch (cleaning position adjustment switch) is pressed and the change to the rearward cleaning position is instructed, the motor 24 reversely rotates the cylinder 40 to retract the nozzle 30 by a predetermined amount. .. When the control device determines that the stop switch of the operation panel 18 is pressed and the bidet cleaning is instructed to be stopped, the control device stops the water supply to the nozzle 30. Then, the rotary gear 45 is rotated in the reverse direction by the motor 24, the nozzle 30 is retracted toward the accommodation position, and the nozzle 30 is accommodated in the cylinder 40. The control device controls the switching valve (motor) so that the cleaning water is ejected from the nozzle washer 60 toward the nozzle 30 on the way from the cleaning position to the accommodation position or when the nozzle 30 reaches the accommodation position. Clean the nozzle 30.

In this way, the nozzle 30 moves back and forth by converting the rotational motion of the cylinder 40 into a linear motion by sliding the protrusion 35 provided at the rear end portion along the spiral groove 44a. As described above, the pitch between the adjacent grooves of the spiral groove 44a is narrower at the front end portion and the rear end portion of the cylinder 40 than at the center portion. Therefore, the amount of advance / retreat of the nozzle 30 per unit rotation of the cylinder 40 is small in the vicinity of the accommodation position and the vicinity of the advance position, and is large in the intermediate position between them. That is, when the buttocks washing or bidet washing is started, the nozzle 30 moves at a relatively high speed until it approaches the washing position, and moves at a relatively slow speed when it approaches the washing position. Further, when the buttocks washing and the bidet washing are completed, the nozzle 30 moves at a relatively high speed until it approaches the accommodation position, and moves at a relatively slow speed when it approaches the accommodation position. This makes it possible to improve the positioning accuracy of the cleaning position and the accommodation position of the nozzle 30 while increasing the moving speed at the intermediate position between the accommodation position and the advance position of the nozzle 30.

In the local cleaning device of the present embodiment described above, the spiral groove 44a provided on the inner peripheral surface of the cylinder 40 and the protrusion 35 provided at the rear end of the nozzle 30 are fitted to each other, and the cylinder 40 rotates. In the nozzle 30 that moves forward and backward, the spiral groove 44a is formed so that the distance between the adjacent grooves at the front end portion and the rear end portion of the cylinder 40 is narrower than that at the center portion. As a result, the cleaning position of the nozzle 30 can be positioned with high accuracy while increasing the moving speed until the nozzle 30 approaches the cleaning position. Further, after the local cleaning is performed, the accommodation position of the nozzle 30 can be positioned with high accuracy while increasing the moving speed until the nozzle 30 approaches the accommodation position.

In the embodiment, the nozzle 30 is formed in a cylindrical shape, but the nozzle 30 is not limited to this, and may be formed in a non-circular shape such as an oval shape or an elliptical shape. In this case, if an opening along the outer shape of the nozzle is formed on the tip surface of the case 50, it is possible to prevent the nozzle from rotating due to the rotation of the cylinder 40 without providing the guide groove 31c and the guide rib 54.

In the embodiment, the spiral groove 44a is formed so that the distance between the adjacent grooves at the front end portion and the rear end portion of the cylinder 40 is narrower than that at the center portion, but the cylinder 40 is not limited to this. It may be formed so that the distance between the adjacent grooves at the tip portion of the cylinder is narrower than that between the central portion and the rear end portion, or the distance between the adjacent grooves at the rear end portion of the cylinder 40 is narrower between the central portion and the tip portion. It may be formed so as to be narrower than the portion.

In the embodiment, the rotary gear 45 is divided into the semi-cylindrical members 41 and 42 so as to form an annular shape in a state where the end faces of the semi-cylindrical members 41 and 42 in the circumferential direction are abutted against each other. As shown in the modified example of FIG. 8, an annular rotary gear 145 that is not divided into one of the two semi-cylindrical members 141 and 142 constituting the cylinder may be provided.

In the embodiment, an annular outer peripheral rib 43 is formed on the outer peripheral surface of the cylinder 40, and an annular inner peripheral groove 53 fitted to the outer peripheral rib 43 is formed on the inner peripheral surface of the case 50. An outer peripheral groove may be formed on the outer peripheral surface of the case 50, and an inner peripheral rib fitted to the outer peripheral groove may be formed on the inner peripheral surface of the case 50. The rib is not necessarily limited to the one formed in an annular shape, and may be formed in an arc shape, and may have any shape as long as it can be fitted to the groove.

In the embodiment, a plurality of protrusions 35 are provided on the outer peripheral surface of the rear end portion of the nozzle 30 as a fitting portion to be fitted with the spiral groove 44a of the cylinder 40, but the present invention is not limited to this, and the nozzle is not limited to this. Balls that can be rolled at equal angle intervals may be arranged on the outer peripheral surface of the rear end portion of the main body 31.

In the embodiment, the rotary gear 45 of the external teeth is provided on the outer peripheral surface of the rear end portion of the cylinder 40 so as to rotate coaxially with the cylinder 40, but the present invention is not limited to this, and the rear end surface of the cylinder 40 is provided. An annular bevel gear such as a face gear may be provided on the cylinder 40 so as to rotate coaxially with the cylinder 40, and the motor may be arranged so that the drive gear attached to the rotating shaft meshes with the bevel gear.

In the embodiment, the cylinder 40 is formed by two semi-cylindrical members 41, 42, but is not limited to this, and may be formed by a single cylindrical member, or may be formed by three or more. It may be formed by a member curved in an arc shape.

In the embodiment, two hoses 21 and 22 are connected to the nozzle 30, and the two nozzle holes 31a and 31b for ejecting the washing water from the corresponding hoses are used for the buttocks cleaning and the bidet cleaning, respectively. They may be used for other different purposes such as for powerful buttocks cleaning and for mild buttocks cleaning, respectively. Further, a nozzle (nozzle unit) may be separately provided for each application. In this case, as described above, the outer diameter of the rotary gear 45 is made smaller than the outer diameter of the case 50 so that the rotary gear 45 provided at the rear end of the cylinder 40 does not protrude from the outer diameter of the case 50. Therefore, even when a plurality of nozzle units are arranged side by side, the entire unit can be made more compact.

The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem will be described. In the embodiment, the cylinder 40 corresponds to a "rotating body", the spiral groove 44a corresponds to a "spiral groove", the rotary gear 45 corresponds to a "rotary gear", the motor 24 corresponds to a "motor", and a nozzle. 30 corresponds to the "nozzle" and the protrusion 35 corresponds to the "fitting portion".

As for the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem, the invention described in the column of means for solving the problem in the embodiment is carried out. Since it is an example for specifically explaining the form for solving the problem, the elements of the invention described in the column of means for solving the problem are not limited. That is, the interpretation of the invention described in the column of means for solving the problem should be performed based on the description in the column, and the embodiment is the invention described in the column of means for solving the problem. It is just a concrete example.

Although the embodiments for carrying out the present invention have been described above with reference to the embodiments, the present invention is not limited to these embodiments and may be in various forms without departing from the gist of the present invention. Of course it can be done.

The present invention can be used in the manufacturing industry of local cleaning equipment and the like.

1 toilet bowl, 10 sanitary washing toilet seat device, 12 toilet seat device body, 13 seating sensor, 14 toilet seat, 16 toilet lid, 18 operation panel, 20 nozzle unit, 21.22 hose, 24 motor, 25 drive gear, 30 nozzles, 31 nozzles Main body, 31a, 31b Nozzle hole, 31c guide groove, 35 protrusion, 40 cylinder, 41, 42 semi-cylindrical member, 43 outer rib, 44 rib, 44a spiral groove, 45 rotary gear, 50 case, 51, 52 semi-cylindrical member, 52a fixing plate, 53 inner groove, 54 guide rib.

Claims (3)

It is a local cleaning device that cleans the local part of the human body.
A cylindrical rotating body with a spiral groove on the inner peripheral surface,
A rotating gear provided on the rotating body coaxially with the rotating body, and
A motor that rotates the rotary gear and
It is provided inside the rotating body, has a spout at the tip capable of ejecting washing water, and has a fitting portion that fits with the spiral groove at the rear end, and is rearward as the rotating body rotates. A nozzle that can move forward and backward along the axial direction of the rotating body between the accommodation position and the forward advance position.
Equipped with
The spiral groove is formed so that the distance between adjacent grooves changes in the axial direction of the rotating body.
Local cleaning equipment. The local cleaning device according to claim 1.
The spiral groove is formed so that the distance between adjacent grooves at the tip of the rotating body is narrower than that at the center.
Local cleaning equipment. The local cleaning device according to claim 1 or 2.
The spiral groove is formed so that the distance between adjacent grooves at the rear end portion of the rotating body is narrower than that at the central portion.
Local cleaning equipment.

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