WO2017164205A1

WO2017164205A1 - Spraying apparatus

Info

Publication number: WO2017164205A1
Application number: PCT/JP2017/011335
Authority: WO
Inventors: 川勝浩石
Original assignee: トリニティ工業株式会社
Priority date: 2016-03-22
Filing date: 2017-03-22
Publication date: 2017-09-28
Also published as: JP2017170287A; JP6725279B2

Abstract

A spraying apparatus comprising: a rotary atomizing head for atomizing paint, said rotary atomizing head being attached at the tip of a hollow rotary shaft of an air motor built into the body of the spraying apparatus; an air motor having an air turbine provided at the rear end side of the hollow rotary shaft, said air turbine having turbine blades formed on the outer periphery of a turbine wheel; a rear surface cover in which are formed exhaust ports for discharging exhaust air from the air motor rearward, and a cylindrical opening through which a feed tube for feeding paint to the rotary atomizing head is inserted inside a hollow space of the hollow rotary shaft from an exhaust chamber side; an air motor housing to which the rear surface cover is attached so as to cover the air turbine; a rearward space in the rear surface cover, said space being formed in an exhaust chamber for discharging exhaust air from the air motor outside of the body of the spraying apparatus; and a gap between the rear surface cover and the turbine wheel, said gap being a leaky air inflow space into which leaky air from the exhaust air flows. In the spraying apparatus: a base, which faces the cylindrical opening, is formed at the base end of the feed tube, and a labyrinth seal is formed, said seal being formed through the meshing, in a contactless state, of at least one annular projection, which is formed on one of the cylindrical opening and the base so as to surround the periphery of the feed tube, and at least one annular recess formed in the other of the opening and the base; the cylindrical opening is formed so as to project forward so as to be inserted in the hollow space from the rear end side of the hollow rotary shaft, and a narrow clearance, which serves as a contactless seal, is formed between the outer peripheral surface of the opening and the inner peripheral surface of the hollow rotary shaft; and a pressure escape flow path is formed closer to the center of the rear surface cover than the exhaust port, and allows the leaky air inflow space and the exhaust chamber to communicate.

Description

Painting machine

The present invention relates to a coating machine that atomizes and sprays paint with a rotary atomizing head that is rotationally driven by an air motor.

As shown in FIG. 5, this type of general coating machine A has a rotary atomizing head 5 attached to the tip of a hollow rotary shaft 4 that is driven to rotate at high speed by an air motor 3 built in the coating machine body 2. The paint supplied through the feed tube 6 inserted into the hollow space 4 s of the hollow rotary shaft 4 is sprayed by being atomized by the rotary atomizing head 5.

The air motor 3 mounted on the coating machine main body 2 has a hollow rotary shaft 4 protruding from the front end side of the motor housing 7 supported by a radial bearing 8, and a turbine wheel 9 a on the rear end side of the hollow rotary shaft 4. The air turbine 9 in which the turbine blade 9b is formed is integrally formed on the outer peripheral portion.

An air supply port 10 for blowing drive air (compressed air) to the turbine blade 9 b is formed around the air turbine 9, and the rear cover 11 fixed to the motor housing 7 so as to cover the air turbine 9 includes a turbine An exhaust port 12 is formed through which exhaust air discharged through the exhaust passage 9c formed on the inner peripheral surface of the blade 9b is discharged rearward.
Further, an exhaust chamber 13 is formed in the interior of the coating machine 2 behind the back cover 11 of the air motor 3, and an exhaust hose (not shown) or the like is connected to the exhaust chamber 13 to paint the exhaust air. The machine body 2 is discharged outside.

Further, as shown in FIG. 6, a feed tube 6 for supplying paint to the rotary atomizing head 5 (see FIG. 5) is inserted into the back cover 11 from the exhaust chamber 13 side into the hollow space 4s of the hollow rotary shaft 4. A cylindrical opening 31 is formed so as to protrude rearward.

Here, when the coating air is supplied through the feed tube 6 while driving air is supplied to the air motor 3 and the rotary atomizing head 5 is driven at a normal rotational speed (for example, about 2 to 40,000 rpm), the coating is rotated and atomized. Centrifugal atomization at the head 5 and spraying.
When spraying paint with a large discharge amount, it is necessary to drive the rotary atomizing head 5 at a higher speed (for example, about 4 to 60000 rpm) in order to maintain atomization. It is necessary to supply a large amount of air at high pressure.

However, when the amount of drive air supplied increases, the pressure loss in the exhaust path increases, and the pressure in the space formed by the exhaust path 9c, the exhaust port 12, and the exhaust chamber 13 (hereinafter referred to as “exhaust space”) increases. Therefore, a part of the exhaust air flows from the exhaust space through the hollow space 4s of the hollow rotary shaft 4 into the rotary atomizing head 5 to increase the pressure in the rotary atomizing head 5, Causes atomization defects.

For this reason, a mechanism has been proposed in which an exhaust port for communicating the inside and the outside of the hollow rotary shaft is provided on the side surface of the hollow rotary shaft to release the pressure in the hollow space (see Patent Document 1).
However, according to the experiment of the present inventor, even when an exhaust port is provided in the hollow rotating shaft, when the amount of inflow into the hollow space increases, the pressure of the exhaust space and the hollow space does not sufficiently decrease. The above problem could not be solved.

For this reason, the present inventors have conceived of blocking the air flow between the exhaust space and the hollow space 4 s of the hollow rotary shaft 4.
As shown in FIG. 6, the exhaust chamber 13 and the hollow space 4 s are communicated with each other via an annular flow path 32 formed in a gap between the outer peripheral surface of the feed tube 6 and the inner peripheral surface of the cylindrical opening 31. However, the gap that becomes the annular flow path 32 needs to have a certain size (about 1 mm interval) in the radial direction for the convenience of inserting the long feed tube 6 in the assembly process of the coating machine. There is.

Therefore, in order to block the annular flow path 32 while maintaining the distance between the outer peripheral surface of the feed tube 6 and the inner peripheral surface of the cylindrical opening 31, as shown in FIG. A coating machine B in which the ring 33 was provided and the exhaust chamber 13 and the hollow space 4s were shut off was prototyped.
When the seal ring 33 is provided in the annular flow path 32 and blocked, the rigid members of the feed tube 6 and the cylindrical opening 31 do not come into contact with each other. Even if the exhaust space becomes high pressure by supplying a large amount of drive air at a high pressure, a large amount of exhaust air does not flow into the hollow space 4s, so that the fine atomization of the paint does not occur.

However, when drive air is supplied at a higher pressure and a larger supply rate in order to further increase the rotation speed of the rotary atomizing head to the maximum allowable rotation speed (for example, about 6 to 80000 rpm), abnormal vibration is rare. Was sometimes observed.
The cause of this abnormal vibration is thought to be due to an increase in the amount of air flowing through the leaked air inflow space 34 formed in the gap between the back cover 11 and the turbine wheel 9a and the disturbance of the pressure distribution in the space 34.
That is, in the coating machine having a conventional structure in which the seal ring 33 is not mounted, air flows from the exhaust space toward the hollow space 4s because the pressure in the hollow space 4s is lower than the exhaust space. Many of them flowed through the annular flow path 32 having a larger gap than the leakage air inflow space 34.
However, the annular flow path 32 that communicates the exhaust chamber 13 and the hollow space 4s is blocked by the seal ring 33, so that the flow path to the hollow space 4s is limited to the leakage air inflow space 34, so that the flow rate flowing therethrough increases. At the same time, the pressure increases, and it is presumed that the pressure distribution in the leaked air inflow space 34 is disturbed due to the rotation of the air turbine 9, and abnormal vibration is likely to occur.

International Publication No. 2015/004966 Pamphlet

Therefore, the present invention reduces the flow rate of the exhaust air flowing from the exhaust space formed by the exhaust path, the exhaust port, and the exhaust chamber to the hollow space of the hollow rotary shaft without using a seal ring, thereby atomizing the paint. In addition to preventing defects, it is a technical subject to prevent abnormal vibrations by suppressing the disturbance of the pressure distribution in the leakage air inflow space.

In order to solve this problem, the present invention is provided with a rotary atomizing head for atomizing paint at the tip of a hollow rotating shaft of an air motor built in the coating machine body,
In the air motor, an air turbine having a turbine blade formed on the outer peripheral portion of the turbine wheel is provided on the rear end side of the hollow rotary shaft, and an exhaust port for exhausting the exhaust air of the air motor to the rear is formed in the housing of the air motor. The rear cover is attached to cover the air turbine,
The rear space of the back cover is formed as an exhaust chamber for discharging the exhaust air of the air motor to the outside of the main body of the paint machine, and the gap between the back cover and the turbine wheel is a leak into which exhaust air leaks. The rear cover is formed with a cylindrical opening through which a feed tube that supplies paint to the rotary atomizing head is inserted into the hollow space of the hollow rotary shaft from the exhaust chamber side. In the painting machine
A base opposite to the cylindrical opening is formed at the proximal end of the feed tube, at least one annular protrusion formed on one of the cylindrical opening and the base, and at least one formed on the other A labyrinth seal formed by meshing the annular grooves in a non-contact state is formed,
The cylindrical opening is formed to protrude forward so as to be inserted into the hollow space from the rear end side of the hollow rotating shaft, and between the outer peripheral surface and the inner peripheral surface of the hollow rotating shaft. A narrow clearance is formed,
A pressure relief flow path that penetrates through the cover and is opened to the exhaust air chamber and the exhaust chamber is formed closer to the center than the exhaust port of the back cover.

According to the present invention, since the base of the feed tube and the cylindrical opening of the back cover are formed to face each other and the space therebetween is formed in the labyrinth seal, the flow that communicates the exhaust chamber and the hollow space of the hollow rotary shaft. A labyrinth seal is formed in the path, and therefore, it is possible to suppress exhaust air from flowing from the exhaust chamber into the hollow space of the hollow rotary shaft.

Further, the cylindrical opening is formed to protrude forward so as to be inserted into the hollow space from the rear end side of the hollow rotary shaft, and becomes a non-contact seal between the outer peripheral surface and the inner peripheral surface of the hollow rotary shaft. Since the narrow clearance is formed, it is possible to suppress the exhaust air from flowing into the hollow space of the hollow rotary shaft through the leaked air inflow space or the pressure relief passage.

Further, since the exhaust chamber and the leaked air inflow space are communicated with each other via a pressure relief passage, the pressure of the leaked air inflow space is synchronized with the pressure of the exhaust chamber with relatively little fluctuation, There is no disturbance in the pressure distribution, and no abnormal vibration occurs when the rotary atomizing head is rotated at the maximum allowable rotation speed.

Explanatory drawing which shows the principal part of the coating machine which concerns on this invention. The partial perspective view. Explanatory drawing which shows the principal part of the other Example which concerns on this invention. Explanatory drawing which shows the principal part of the further another Example which concerns on this invention. Explanatory drawing which shows the structure of a common coating machine. Explanatory drawing which shows the principal part of the conventional coating machine. Explanatory drawing which shows the principal part of the conventional coating machine.

The present invention prevents paint atomization failure by suppressing the flow rate of exhaust air flowing into the hollow space of the hollow rotary shaft from the exhaust space composed of the exhaust passage, the exhaust port, and the exhaust chamber without using a seal ring. In addition, in order to achieve the object of preventing abnormal vibration by suppressing the disturbance of the pressure distribution in the leakage air inflow space, the following configuration is provided.
That is, a rotary atomizing head for atomizing paint is attached to the tip of the hollow rotary shaft of an air motor built in the coating machine body,
In the air motor, an air turbine having a turbine blade formed on the outer peripheral portion of the turbine wheel is provided on the rear end side of the hollow rotary shaft, and an exhaust port for exhausting the exhaust air of the air motor to the rear is formed in the housing of the air motor. The rear cover is attached to cover the air turbine,
The rear space of the back cover is formed as an exhaust chamber for discharging the exhaust air of the air motor to the outside of the main body of the paint machine, and the gap between the back cover and the turbine wheel is a leak into which exhaust air leaks. The rear cover is formed with a cylindrical opening through which a feed tube that supplies paint to the rotary atomizing head is inserted into the hollow space of the hollow rotary shaft from the exhaust chamber side. In the painting machine
A base opposite to the cylindrical opening is formed at the proximal end of the feed tube, at least one annular protrusion formed on one of the cylindrical opening and the base, and at least one formed on the other A labyrinth seal formed by meshing the annular grooves in a non-contact state is formed,
The cylindrical opening is formed to protrude forward so as to be inserted into the hollow space from the rear end side of the hollow rotating shaft, and between the outer peripheral surface and the inner peripheral surface of the hollow rotating shaft. A narrow clearance is formed,
Near the center of the exhaust port of the back cover, a pressure relief passage that penetrates the cover and opens into the leakage air inflow space and the exhaust chamber is formed.

FIG. 1 is an explanatory view showing a main part of a painting machine T1 according to the present invention, and common components are common to the painting machine shown in FIG.
The cylindrical opening 21 formed in the back cover 11 of the motor housing 7 is formed to protrude forward so as to be inserted in a non-contact state from the rear end side of the hollow rotary shaft 4. The cylindrical opening 21 may be formed integrally with the back cover 11 or may be attached and fixed integrally to the back cover 11 as an accessory.

A base 22 facing the cylindrical opening 21 is formed at the base end of the feed tube 6, at least one annular protrusion 23 a formed on the base 22, and at least one annular formed on the cylindrical opening 21. A labyrinth seal 23 is formed by engaging the concave grooves 23b in a non-contact state.
The base 22 may be formed integrally with the feed tube 6 or may be attached and fixed integrally to the base end of the feed tube 6 as an accessory.

Further, as shown in FIG. 2, the annular protrusion 23a and the annular concave groove 23b are formed so as to surround the feed tube 6 in a circular shape, and the width, height, and depth thereof are respectively In the state where the feed tube 6 is assembled at an appropriate position, each gap is designed to be 0.3 mm or less.
Thereby, a part of the flow path from the exhaust chamber 13 to the hollow space 4 s of the hollow rotary shaft 4 through the gap between the inner peripheral surface 21 a of the cylindrical opening 21 and the feed tube 6 is formed as the labyrinth seal 23. It will be.

In addition, as shown in FIG. 3, the case where the cyclic | annular protrusion 23a is formed in the cylindrical opening part 21 and the cyclic | annular concave groove 23b is formed in the base 22 may be sufficient, and the shape is not restricted to circular ring shape. For example, the feed tube 6 may be formed in a square ring surrounding the square.
Moreover, although FIG.1 and FIG.3 demonstrated the case where a pair of annular protrusion 23a and the annular groove 23b were formed, the number is also arbitrary.

Between the outer peripheral surface 21 b of the cylindrical opening 21 and the inner peripheral surface 4 a of the hollow rotary shaft 4, a narrow clearance that forms a non-contact seal 24 is formed.
Since the back cover 11 is fixed to the motor housing 7, the cylindrical opening 21 formed in the back cover 11 can be centered with high accuracy with respect to the inner peripheral surface 4 a of the hollow rotary shaft 4.
Therefore, the narrow clearance that becomes the non-contact seal 24 can be designed with an accuracy of 0.1 mm or less. In this example, the gap is designed to be 0.3 mm or less according to the pressure loss caused by the non-contact seal 24. ing.

The gap between the back cover 11 and the turbine wheel 9a is a leakage air inflow space 25 into which the leakage air of the exhaust air that has not been discharged from the exhaust port 12 flows, and is closer to the center than the exhaust port 12 of the back cover 11, A plurality of pressure relief passages F are formed through the cover 11 and open to the leakage air inflow space 25 and the exhaust chamber 13.
In this example, the pressure relief flow path F is formed through the back cover 11 so as to be substantially parallel to the axial direction of the feed tube 6.

The above is one configuration example of the present invention, and the operation thereof will be described next.
When drive air is supplied to the air motor 3, the drive air is blown from the air supply port 10 to the turbine blade 9b and the turbine 9 is rotated, whereby the hollow rotary shaft 4 and the rotary atomizing head 5 are driven to rotate at high speed.
Most of the exhaust air is discharged rearward from the exhaust port 12, passes through the exhaust chamber 13, and is led to the outside by an exhaust hose (not shown) or the like.
A part of the exhaust air flows into the leaked air inflow space 25 in the gap between the turbine wheel 9 a and the back cover 11.

At this time, since the space between the base 22 of the feed tube 6 and the cylindrical opening 21 is formed in the labyrinth seal 23 in the flow path from the exhaust chamber 13 to the hollow space 4 s of the hollow rotary shaft 4, It is possible to suppress the passage of exhaust air from the exhaust chamber 13 into the hollow space 4s.
In addition, since the non-contact seal 24 is formed in the flow path that passes through the gap between the outer peripheral surface of the cylindrical opening 21 and the inner peripheral surface of the hollow rotary shaft 4 and reaches the hollow space 4s, The exhaust air that has flowed into the pressure relief flow path F can be prevented from flowing into the hollow rotary shaft 4.
Accordingly, a large amount of exhaust air does not flow into the hollow space 4s, and poor atomization of the paint is prevented.

Further, the exhaust chamber 13 and the leaked air inflow space 25 are communicated with each other via the pressure relief flow path F, and the volume of the exhaust chamber 13 is sufficiently larger than the leaked air inflow space 25. It synchronizes with the pressure of the exhaust chamber 13 with relatively little fluctuation, and there is no disturbance in the pressure distribution of the leaking air inflow space 25, and abnormal vibration occurs when the rotary atomizing head is rotated at the maximum allowable rotational speed. It does not occur.

FIG. 4 is an explanatory view showing a main part of another embodiment. 3 and 7 are denoted by the same reference numerals, and detailed description thereof is omitted.
In the coating machine T2 of this example, the cylindrical opening 21 is formed so as to protrude rearward of the back cover 11, and the back side outer periphery of the cylindrical opening 21 is formed on the base 22 formed at the base end of the feed tube 6. A cylindrical cover 26 surrounding the surface 21c is formed.
The cylindrical cover 26 may be integrally formed with the base 22 of the feed tube 6 or may be integrally attached to the base 22 as an accessory.

The front end of the cylindrical cover 26 is formed as an annular protrusion 27a that reaches the back cover 11, and an annular groove 27b is formed in the back cover 11 at a portion facing the annular protrusion 27a.
In addition, at least one annular protrusion 28 a is formed on the rear end surface of the cylindrical opening 21, and at least one annular concave groove 28 b is formed on the base 22 at a portion facing this.
Then, the labyrinth seal 29 is formed by meshing the

annular protrusions

27a and 28a and the annular

concave grooves

27b and 28b in a non-contact state. Other configurations are the same as those of the first embodiment shown in FIG.

Also in this example, since the labyrinth seal 29 with high pressure loss is formed in the flow path from the exhaust chamber 13 to the hollow rotary shaft 4, the inflow of exhaust air from the exhaust chamber 13 to the hollow space 4s is suppressed, Since the non-contact seal 24 is formed between the outer peripheral surface of the cylindrical opening 21 and the inner peripheral surface of the hollow rotary shaft 4, the exhaust air flowing into the leaked air inflow space 25 flows into the hollow rotary shaft 4. It is suppressed, thereby preventing atomization failure.

Further, since the leakage air inflow space 25 and the exhaust chamber 13 are communicated with each other by the pressure relief flow path F, the pressure of the leakage air inflow space 25 is synchronized with the pressure of the exhaust chamber 13 with relatively little fluctuation. There is no disturbance in the pressure distribution in the inflow space 25, and no abnormal vibration occurs when the rotary atomizing head is rotated at the maximum allowable rotation speed.

The present invention can be applied to the application of a coating machine in which a rotary atomizing head that atomizes paint is rotated by an air motor built in the main body of the coating machine.

T1, T2 Painter 2 Painter body
3 Air motor
4 Hollow rotating shaft
4s hollow space 5 rotating atomizing head
6 Feed tube
7 Housing 9 Air turbine 9 a Turbine wheel 9 b Turbine blade 11 Back cover 12 Exhaust port 13 Exhaust chamber 21 Cylindrical opening 22 Base 23 Labyrinth seal

23a Annular projection

23b Annular groove 24 Non-contact seal
25 Leaky air inflow space
F Pressure relief passage
27a 28a Annular projection 27b 28b Annular groove 29 Labyrinth seal

Claims

A rotary atomizing head that atomizes the paint is attached to the tip of the hollow rotary shaft of the air motor built in the coating machine body,
In the air motor, an air turbine having a turbine blade formed on the outer peripheral portion of the turbine wheel is provided on the rear end side of the hollow rotary shaft, and an exhaust port for exhausting the exhaust air of the air motor to the rear is formed in the housing of the air motor. The rear cover is attached to cover the air turbine,
The rear space of the back cover is formed as an exhaust chamber for discharging the exhaust air of the air motor to the outside of the main body of the paint machine, and the gap between the back cover and the turbine wheel is a leak into which exhaust air leaks. The rear cover is formed with a cylindrical opening through which a feed tube that supplies paint to the rotary atomizing head is inserted into the hollow space of the hollow rotary shaft from the exhaust chamber side. In the painting machine
A base facing the cylindrical opening is formed at the base end of the feed tube, and at least one annular protrusion formed on one of the cylindrical opening and the base so as to surround the periphery of the feed tube; A labyrinth seal formed by meshing at least one annular groove formed on the other side in a non-contact state is formed,
The cylindrical opening is formed to protrude forward so as to be inserted into the hollow space from the rear end side of the hollow rotating shaft, and between the outer peripheral surface and the inner peripheral surface of the hollow rotating shaft. A narrow clearance is formed,
A pressure relief passage is formed in the leaking air inflow space and the exhaust chamber so as to pass through the cover closer to the center than the exhaust port of the back cover.
The coating machine according to claim 1, wherein the annular protrusion and the annular groove are formed in a circular shape surrounding the feed tube.
The coating machine according to claim 1, wherein a clearance between the labyrinth seal and the non-contact seal is 0.3 mm or less.