EP2066451A1

EP2066451A1 - Electrostatic spraying arrangement

Info

Publication number: EP2066451A1
Application number: EP07818465A
Authority: EP
Inventors: Michael Baumann; Frank Herre; Jürgen Haas; Harry Krumma; Hans-Jürgen Nolte; Marcus Frey; Bernhard Seiz; Herbert Martin; Erwin Bieber; Torsten Block
Original assignee: Duerr Systems AG
Current assignee: Duerr Systems AG
Priority date: 2006-09-27
Filing date: 2007-09-26
Publication date: 2009-06-10
Anticipated expiration: 2027-09-26
Also published as: MX2009002988A; CA2663245C; RU2009115657A; JP5312331B2; EP2066451B1; ATE508804T1; BRPI0717421B1; US20100147215A1; KR20090057020A; RU2441709C2; KR101452349B1; JP2010504850A; PL2066451T3; WO2008037456A1; BRPI0717421A2; US8485125B2; CA2663245A1

Abstract

The invention relates to an electrostatic spraying arrangement for the serial coating of workpieces, wherein the high-voltage sensors (7) and actuators (6) of the sprayer (11) are supplied by an isolating transformer (T1-T3) in the sprayer (11) and/or in a robot arm (10) with a high voltage insulation path. Control and sensor signals for the actuators (6) and sensors (7) are transmitted potential-free, for example, optically or by radio.

Description

Electrostatic atomizer arrangement

The invention relates to an atomizer arrangement for a coating machine for series-wise electrostatic coating of workpieces such as motor vehicle bodies or parts thereof. The atomizer arrangement can consist in particular of an electrostatic atomizer and the forearm (arm 2) of a coating robot exist where the atomizer is arranged on the usual wrist.

Electrostatic atomizers are known. In the case of rotary atomizers, in addition to a turbine (ie a pneumatic or hydraulic drive) or an electric motor for driving the atomising bell, they contain various components such as e.g. Valves, valve terminals, bus connection modules for fieldbus systems, valve controllers, drive control loops and other controllers of all kinds, inductive, optical and / or capacitive sensors, high voltage generators, etc.

In atomizers working with direct charging of the coating material, usually the entire atomizer is placed under high voltage so that the coating material is charged by an electrode device containing all the electrically conductive parts such as atomizer, paint tube, fittings, etc., with which it comes into contact. However, it is known that external charging of the coating material with external electrodes is also possible.

An electrostatic rotary atomizer which contains an electric motor controlled by a safety transformer is known from WO 2005/110613. Further information NEN via electrostatic atomizers and their components can be found for example in EP 0 219 409, EP 1 245 291, EP 1 293 308 and EP 1 394 757.

EP 1 232 799 describes an air atomizer with easily separable and interconnectable components, at the separation points correspondingly easily detachable and connectable electrical line connections are required. Instead of plug contacts used for this purpose, the line connections in this air atomizer from inductive couplers with two flat coils, in particular Topfkernbauweise, which should be so small that virtually no structural changes of instead connectable by plug separable parts of the atomizer are required.

From DE 103 09 143 it is known to supply pig sensors to a high-voltage molten paint delivery line via an isolating transformer with the voltage they require and to transmit the sensor signals from the high voltage range via optocouplers to an external evaluation circuit.

The use of the high voltage during the application requires high insulation distances between the components lying at high voltage or low potential, which can also be partially in the arm of a robot serving as a coating machine. However, the space available in the nebulizer arrangement often prevents separation between high-voltage components and grounded or low-potential components. As a result, complete charging of the components in the atomizer assembly may be required. An electrostatic sprayer includes various components that are to be supplied with electrical power and / or receive and / or transmit electrical signals. All actuators and sensors and other electronic components of the atomizer require electrical supply, and all the actuators provided there require signals coming from the outside, while all sensors and other electronic components deliver, for example, diagnostic data and other signals to the outside, in particular also actual values from externally controlled parameters the atomizer.

The aim of the invention is in particular an expedient and trouble-free supply of components of a high-voltage nebulizer arrangement with electrical power at potential separation between an external supply line arrangement and the consumers of the nebulizer.

This object is solved by the features of claim 1.

The invention is based on the recognition that a transformer arrangement provided at least partly in the atomizer or in an adjacent moving member of the coating machine, namely in the front of a coating robot or possibly outside the coating machine, as for example for supplying and controlling an electric drive motor of the atomizer per se can already be present, useful for dining other components of the atomizer can be used. The transformer can bring about galvanic isolation between the line arrangement provided for the power supply of the atomizer arrangement and consumers located in the atomizer or possibly in the robot arm, which are at high voltage. This separation is best carried out with an isolating transformer which has a sufficient insulation gap or other insulation device between see the primary and secondary circuits has. It should be noted that different components require different supply voltages. For example, a frequency controlled drive of the atomizer requires different voltages and frequencies than a consumer requiring only a constant DC voltage (eg, 24V).

According to another aspect, the invention makes it possible to easily transmit signals transmitted or received by sensors, actuators, controls and / or other electrical components of the atomizer assembly into or out of the atomizer assembly, although in operation these components are at high voltage. This problem is solved by transmitting the signals with galvanic isolation. The galvanic separation can be realized in different ways, in particular by preferably digital information or data transmission via optical waveguides or radio links or as sound signals or else by amplitude or frequency modulation of e.g. from a transformer arrangement with high-voltage insulation in the high voltage range of the atomizer arrangement led supply voltages.

The invention will be explained in more detail with reference to the drawing. Show it

1 shows an atomizer arrangement with a transformer arrangement according to the invention;

Fig. 2 is a schematic representation of a preferred embodiment of the transformer arrangement;

3 shows the basic diagram of a signal transmission via optical waveguide; and Fig. 4 shows the schematic diagram of a signal transmission over a radio link.

1, in the region 1, the components of an electrostatic rotary atomizing arrangement which are at high voltage potential during operation, namely the actual atomizer or an arrangement of the atomizer, a wrist and the forearm of a high-voltage coating robot. The forearm can be made in a conventional manner of insulating material. With the exception of the primary circuits of the transformer arrangement described below, all of the components considered in region 1 can be at the high-voltage potential.

For the electrical supply of this area 1 leads a two- or multi-pole external supply line arrangement 2, which, as shown, the parallel primary coils of the three in a conventional manner as isolating transformer with high-voltage insulation paths (for more than 100 or 150 kV) formed transformers Tl, T2 and T3 feeds.

The AC voltage of the line arrangement 2 feeds the primary coil of the first transformer Tl via a converter 3 with voltage pulses which feed on the secondary side the frequency-controlled drive 4 of an electric motor M located in the high voltage area 1, which instead of the one in FIG Rotary atomizers otherwise conventional air turbine is provided for driving the atomizer and can be located in the atomizer itself or in other cases outside eg in or on the forearm of the robot. The motor M, for example, the above-mentioned WO 2005/110613 Al correspond. Accordingly, the AC voltage generated on the secondary side of the transformer Tl can be converted into an optionally controlled variable DC voltage of, for example 40 V, which can be superimposed on an AC voltage with the speed control or - control of the motor controllable frequency. This DC voltage can then be converted into an AC voltage supplying the motor M with a frequency corresponding to the superimposed frequency. For feeding and controlling the motor M, however, other known electrical systems can also be used, wherein the speed can be controlled, for example, in a known manner by changing the synchronizing frequency and wherein the power supply can also be separated from, for example, a digital speed control.

Instead of the electric motor M could also be provided a pneumatic or hydraulic drive for the Zestäuberglocke. When using an electric motor, it may be appropriate to dimension it so that it can be easily replaced in existing atomizers with their conventional air turbine.

The secondary coil of the second transformer T2, on the other hand, according to the invention, is used to supply power to the components, including actuators 6, sensors 7 and electronic elements of the atomizer, which are located in the high-voltage region 1. As shown, the AC voltage generated by the transformer T2 can be converted by a converter 5 into a DC supply voltage. Typical examples of the components indicated only schematically in FIGS. 6 and 7 are actuators such as control and drive circuits for valves and flow, speed and other control circuits as well as sensors for the switching position of valves, speed, flow rate, temperature, pressure of the valve loading Stratification material, etc. The actuators considered here may include, for example, other electrical or other motors such as metering pump drive.

For the power supply of the sensors and actuators, in other embodiments, one could also be used in the motor control, e.g. the drive 4 generated DC voltage can be used. Furthermore, in other cases it is possible to use electric batteries for the power supply of individual sensors and / or actuators in a manner known per se or possibly also other separate power sources such as fuel cells. However, the power supply of the components of the atomizer by a for other purposes such as in particular an electric drive motor anyway existing transformer arrangement has the advantage that the power consumption is reduced to a minimum.

The secondary coil of the third transformer T3 feeds a converter 9, which generates the high voltage required for the electrostatic charging of the coating material from the input AC voltage or supplies a high voltage generator, not shown, of the atomizer. The high voltage is applied to the internal or external electrode arrangements (not shown) customary for electrostatic atomizers for direct or external charging of the coating material.

In addition to the sensors and actuators of the atomizer, other components of the application technology located outside the atomizer can also be fed by the transformer arrangement according to the invention, ie also actuators and sensors of the application technology located at other locations of the coating machine and there at high voltage potential or even low or ground potential. This also includes components that, depending on the system, can be at high voltage or earth potential, such as color changers. Eventually, the transformer arrangement can supply all of the application-related components present on a robot, for example, with the electrical power they require in each case.

By mounting relatively heavy standard constructions for the transformer assembly as separate components in the atomizer or in the robotic arm of, for example, a paint robot, they could affect its motion dynamics. It may therefore be more appropriate to structurally integrate the transformer or a transformer coil into the body of the robot arm so that it serves as a supporting element of the robot arm and effects or at least contributes to its necessary rigidity. As a result, the transformer does not significantly increase the overall weight of the atomizer assembly, including the robotic arm.

A possible realization thereof is shown schematically in Fig. 2, in which a pivotally mounted robot arm 10 can be seen, is mounted at one (left) end via a wrist of the indicated at 11 atomizer, while at its opposite end the usual axis housing 12 is located with the manual axis motors required for the atomizer movements. The housing 12 may be low or grounded.

The outer housing of the robot arm 10 is formed or supported on its inner side by a transformer coil 14 adapted to the geometric shape of the robot arm, which thus effects the required mechanical strength of the robot arm 10. As already mentioned, the robot arm 10, including the secondary coil in this example, can Transformer coil 14 are at high voltage potential. The primary coil of the transformer connected to the external supply line arrangement 2 (FIG. 1), which is high-voltage-insulated, can be located in the housing 12 or in its vicinity at a low or ground potential point in the arm 10 in an inductive manner.

It is also conceivable to mount the transformer arrangement considered here at least partly in the other (rear) robot arm 16 or in a component "mounted" (axis 7) separate from the arms 10 and 16, wherein the components of the primary side by the high-voltage insulation device galvanically isolated secondary side as in the other embodiments may be galvanically connected to the lying on high voltage to be supplied elements.

The transmission of control and sensor signals to and from the actuators and sensors located in the high-voltage region 1 (FIG. 1) must be carried out galvanically isolated in order to preclude influences due to the high voltage. For this purpose, the possibilities of optical transmission or a radio link are considered below, which may also be useful independently of the power supply with a transformer described above.

Referring to Fig. 3, in the high voltage region 1 there is provided an electrical / optical transducer assembly 20 which generates, e.g. digital sensor signals in optical

Converts signals and incoming optical control signals into eg digital control signals. The optical sensor and control signals are bidirectionally via an optical fiber array LWL between the transducer assembly 20 and an exceptional half of the high voltage region located external transducer assembly 21 transmitted. The transducer assembly 21 can convert the optical signals back into electrical, eg digital signals. The optical transmission is known to be potential-free. The signal conversion at the respective end of the fiber optic cable forming the optical waveguide arrangement from optical into electrical signals or vice versa can be carried out with commercially available components. Both individual signals can be transmitted as well as complex bus signals, which allows the use of known fieldbus systems and their components.

The data in and out of the high-voltage area 1 can also be transmitted via a radio link, as shown in FIG. 4. There is a radio link 25 between a located in the high voltage range 1 transducer assembly 26, which converts the aforementioned sensor or control signals into radio signals, and an external transducer assembly 27, which converts the radio signals back into electrical signals. Commercially available systems can be used which establish radio links, for example via Bluetooth or with the wireless networks known as WLAN. This is especially the transmission of large amounts of data possible. There is also the possibility of transferring the data to an area outside the robot, whereby the necessary

Cable connections in the robot can be reduced to a minimum. The signal transmission over a radio link is known also potential free. The signal conversion at the respective end of the radio link 25 into electrical signals or radio signals can be carried out in a conventional manner with conventional transmitting or receiving components. Here, too, individual signals can be transmitted as well as complex bus signals, so that the use of known fieldbus systems and their components is possible. Also the signal transmission By radio is bidirectional, ie on the considered transmission medium signals are transmitted in both directions.

Bluetooth is a well-known industry standard according to IEEE 802.15.1 for the wireless radio networking of devices over a relatively short distance up to about 100 m. The networked devices can transmit in the ISM band (Industrial, Scientific and Medical Band) between 2.402 GHz and 2.480 GHz. To achieve robustness to interference in the same frequency band, a frequency hopping method is used, in which the frequency band is divided into a plurality (79) of frequency stages, for example, in the 1 MHz distance, which changes up to 1600 times a second become. There are also data packets in which the frequency is changed less often. At the lower and upper end there is a respective frequency band as a guard band to adjacent frequency ranges. With EDR (Enhanced Data Rate), data can be transmitted at about 2.1 Mbps. Currently, a Bluetooth device can simultaneously sustain up to seven connections, with devices sharing the available bandwidth. There are several types of error handling available: 1/3 FEC (Forward Error Control) with two repetitions of each bit, 2/3 FEC using a generator polynomial to encode 10 bits in 15 bits, and ARQ (Automatic Repeat Request), wherein a data packet is repeated until a positive acknowledgment is received or a time limit is exceeded. WLAN (Wireless Local Area Network), on the other hand, refers to networks according to IEEE 802.11, which can be operated in infrastructure mode or in ad hoc mode. In infrastructure mode, the individual network nodes are coordinated by a base station, which makes it easy to connect to wired networks; in ad hoc mode, there is no station especially excellent, but all are equal. Ad hoc networks can be set up quickly and easily. For WLAN also methods for increasing the security of data transmission are known.

To ensure secure data transmission by radio, for example via WLAN or via Bluetooth, u.a. the known as frequency spreading known method are used in which a narrow-band signal is converted into a broadband signal. The transmission energy, which was previously concentrated in a small frequency range, is distributed over a wider frequency range. A resulting advantage is greater robustness over narrowband interference. In addition, frequency spreading in digital technology is used to determine the spectral density of the

Reduce clock signals to achieve better electromagnetic compatibility. The method can be carried out in different ways. With the DSSS (Direct Sequence Spread Spectrum) method, the user data is linked with a code by means of an exclusive OR (XOR) and then modulated to the bandwidth. This method is generally used in combination with the CDMA technique and can be used in particular for WLAN according to the standard IEEE 802.11 and the mobile radio standard UMTS. Frequency hopping based frequency spreading techniques divide the available bandwidth among many smaller bandwidth channels in terms of frequency division multiplexing. This method can i.a. be used with Bluetooth.

In general, it is expedient to electronically monitor the described signal transmission via the optical waveguide arrangement LWL or the radio link 25 with a system to which a security software program belongs that monitors the transmission path and the transmitted information checked for plausibility. One possibility, for example, is to transmit the given data packet, eg frequency-modulated several times, eg five times during information data transmission and to check on the other side whether at least two identical data packets arrive, ie the radio or other transmission path is in order. In the event of errors, safety-related components of the atomizer assembly and / or the transmission path can be switched off in order to protect objects and persons. With an error message, the operating personnel can be informed about the detected condition. In particular, the following monitors can be constantly active: control of the optical transmission path or the radio connection; Plausibility of the transmission information (protocols); as well as shutdown function of the entire system in case of error and informing the operating personnel.

Instead of the described optical or radio transmission links, there is also the possibility of a preferably bidirectional acoustic signal transmission. For this likewise potential-free transmission technology (which, for example, has already been proposed for the speed control of atomizers), sound level signals can be generated using microphones, passed through a hose and converted back into electrical signals at the reception location.

Another possibility for the floating transfer of control signals to the high-voltage region of a nebulizer arrangement is to superimpose the input voltage of the above-described transformer arrangement components containing control information, which are filtered out again on the secondary side and used as control signals for components located in the high-voltage region can. The superimposed components may, for example, be an optionally digital frequency or amplitude modulation of the input voltage. Instead, it is also possible to transmit a controlled according to a desired control function AC signal separated from the input voltage of the other functions provided for transformer arrangement (Tl, T2, T3) via a separate transformer with high voltage insulation in the high voltage range. In particular, according to each of these possibilities, the rotational speed of the possibly electric drive motor of the atomizer can also be controlled and / or regulated in the closed loop. In a manner similar to the described transmission of control signals into the atomizer arrangement, sensor signals from the atomizer arrangement can also be transmitted to a low or earth potential area in or outside the coating machine.

In a modification of the described embodiment, it is also possible to supply the

Arranged atomizer assembly to arrange outside the painting robot, e.g. even in a cupboard outside the paint booth. This could be useful, for example, to avoid explosion protection problems. The then required high-voltage insulation between the transformer and the atomizer can be realized in a manner known to those skilled in the art within leading to the painting robot or atomizer line arrangement.

Claims

A nebulizer assembly for a coating machine for serial electrostatic coating of workpieces, comprising an electrostatic atomizer (11) having means for charging the coating material to high voltage and including components including actuators (6) and sensors (7), at least some of which are incorporated herein by reference Operation are at the high voltage potential, and with a to an external supply line (2) connected to the transformer assembly (T1-T3), at least partially within the atomizer (11) or the Zer-Stäuberanordnung and / or in a component (10) of Coating machine or outside the coating machine, characterized in that the transformer arrangement (Tl-T3) has a high-voltage insulation device between its primary and secondary circuits or a high-voltage insulation device.

Isolation device is provided in a leading from the transformer assembly to the atomizer assembly line arrangement, and that the transformer assembly located in the atomizer assembly located on the high voltage potential sensors (7) and / or actuators (6) including

Valve controls is connected and supplies them with the electrical power they need.

2. Atomizer assembly according to claim 1 with a rotary atomizer, which contains one of a transformer assembly (Tl) powered and / or controlled electric drive motor (M) for the rotating spray element of the atomizer (11).

3. atomizer assembly according to claim 1 or 2, characterized in that the atomizer (11) or the moving member (10) of the coating machine contains one of the transformer assembly (T3) of the atomizer powered high-voltage generator (9).

4. Atomizer arrangement according to one of the preceding claims, characterized in that the transformer arrangement (T1-T3) is located at least partially in a movement member forming the arm of a (10) coating robot.

5. An atomizer assembly according to claim 4, characterized in that in the robot arm (10) befindlicher part (14) of the transformer assembly is in operation at high voltage potential.

6. An atomizer assembly according to claim 4 or 5, characterized in that a part (14) of the transformer assembly is structurally integrated into the body of the robot arm (10), so that it contributes to its mechanical strength.

An atomizer arrangement for a coating machine for serial electrostatic coating of workpieces with an electrostatic atomizer (11) having means for charging the coating material to high voltage and having a high voltage potential in operation in which components including actuators (6 ) and sensors (7) are, in particular according to one of claims 1 to 6, characterized in that of sensors (7), actuators (6), controls and / or other electrical components of the atomizer sent and / or received signals galvanic overall separates into or out of the lying on high voltage potential area (1) of the atomizer.

8. Atomiser arrangement according to claim 7, characterized in that the signals of all the atomizers (11) located in the actuators (6) and sensors (7) are galvanically separated into or out of the area lying at high voltage potential (1).

9. atomizer arrangement according to claim 7 or 8, characterized in that optical waveguides (LWL) are provided for the floating transmission of the signals.

10. Atomizer arrangement according to one of claims 7 to 9, characterized in that a radio link (25) is provided for transmitting the signals.

11. Atomizer arrangement according to claim 10, characterized in that a Bluetooth system or a WLAN system is used as the radio link (25).

12. Atomizer arrangement according to one of claims 7 to 11, characterized in that on the same transmission path (LWL, 25), a bidirectional signal transmission takes place.

13. Atomizer arrangement according to one of claims 7 to 12, characterized in that the signals transmitted to and / or from the atomizer arrangement are superimposed on the voltages of a transformer arrangement.

14. Atomizer arrangement according to one of claims 7 to 13, characterized in that a system for checking the correctness of the received signals is provided.

15. An atomizer arrangement according to one of claims 7 to 14, characterized in that an electronic monitoring device with a monitoring software for monitoring the transmission path (LWL, 25) and for checking the transmitted information is provided which generates an error message when detected by the monitoring software errors.