Coating device and associated operating method

Abstract

A coating device, e.g., for painting motor vehicle bodies, comprises a sprayer for applying a coating material by means of an application element and an internal color-changer valve assembly, said assembly having several color inlets for selecting coating materials of different colors. The internal color-changer valve assembly is integrated into the sprayer and is connected by its outlet to the application element, in order to feed the selected coating material to the application element. Further, an external color-changer valve assembly has several color inlets for selecting coating materials of different colors, said external color-changer assembly having a separate structure from the sprayer and being connected by its outlet to the application element, in order to feed the selected coating material to the application element. An operating method corresponds to the device.

Claims

1. A coating device, for painting motor vehicle bodies, comprising: an atomiser for applying a coating agent by an application element; an internal color-changer valve assembly to supply high runner paints with a plurality of paint inlets for selecting coating agents of different colors and a high runner paint outlet, where the internal color-changer valve assembly is structurally integrated into the atomiser and directly connected to a main needle valve at the high runner paint outlet end, to supply the application element with the selected coating agent wherein the internal color changer is proximate the main needle valve such that no recirculation valve is positioned downstream from the internal color changer; and an external color-changer valve assembly to supply low runner paints with a plurality of paint inlets for selecting coating agents of different colors and a low runner paint outlet, where the external color-changer valve assembly is structurally separate from the atomiser and the low runner paint outlet is connected to the main needle valve through a first separately actuatable valve, to supply the application element with the selected coating agent; wherein a first recirculation valve is provided, which facilitate recirculation for the lower runner paint outlet of the external color-changer valve assembly.

2. The coating device in accordance with claim 1, wherein the recirculation valve is structurally integrated into the atomiser.

3. The coating device in accordance with claim 1, wherein the recirculation valve is structurally separate from the atomiser.

4. The coating device in accordance with claim 1, wherein a) the internal color-changer valve assembly is fed with coating agents of different colors by a first metering device, and b) a second metering device feeds the coating agents from the external color-changer to the separately actuatable valve.

5. The coating device in accordance with claim 4, wherein the first metering device is structurally separate from the atomiser, and is located on a component selected from the group consisting of: a) a proximal robot arm of a painting robot, b) a distal robot arm of a painting robot, c) a body of a painting robot, d) a stationary component in a painting cabin, e) a stationary component outside a painting cabin.

6. The coating device in accordance with claim 4, wherein the external color-changer valve assembly and the second metering device allocated thereto are mounted on a component selected from the group consisting of: a) a proximal robot arm of a painting robot, b) a distal robot arm of a painting robot.

7. The coating device in accordance with claim 4, wherein the first metering device and the second metering device are in the form of a geared pump.

8. The coating device in accordance with claim 7, wherein: the geared pump has a plurality of pumping chambers, each containing a pair of gearwheels configured to rotate within their respective chambers, the individual pumping chambers each supply paint to at least one of the paint inlets of the atomizer and the internal color-changer valve assembly; and the geared pump has a common drive shaft to drive the individual pairs of gearwheels.

9. The coating device in accordance with claim 8, wherein the geared pump includes a plurality of clutches configured to selectively engage the drive shaft with the individual pairs of gearwheels.

10. The coating device in accordance with claim 8, wherein a) the pumping chambers are behind each other in the axial direction of the drive shaft, and b) the immediately adjacent pumping chambers have a common chamber wall.

11. The coating device in accordance with claim 1, wherein a) the atomiser has a first sub-assembly in which the internal color-changer valve assembly is located; b) the atomiser has a second sub-assembly with a bell plate application element, and c) the first sub-assembly is separably connected to the second sub-assembly.

12. The coating device in accordance with claim 1, wherein the atomiser is selected from the group consisting of: a) a rotary atomiser; b) an ultrasonic atomiser; c) an air atomiser; d) an airless device; e) an airmix device.

13. The coating device in accordance with claim 1, wherein the coating agent is selected from the group consisting of: a) water-based paint; b) solvent-based paint; c) powder lacquer; d) joint sealant.

14. The coating device in accordance with claim 1, wherein the coating agent is selected from the group consisting of: a) filler; b) base coat; c) clear varnish.

15. The coating device in accordance with claim 8, wherein the respective pairs of gearwheels of each pumping chamber are spaced axially from each other along the driveshaft.

16. The coating device in accordance with claim 8, wherein the plurality of pumping chambers are each spaced axially from each other with respect to the driveshaft.

17. The coating device in accordance with claim 8, wherein the plurality of pumping chambers share a plate, the plate defining a chamber wall of each of the plurality of pumping chambers.

18. The coating device in accordance with claim 8, wherein the driveshaft includes a key disposed within the driveshaft, the key configured to move axially along the driveshaft to selectively engage each of the gearwheels.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Other advantageous embodiments of the invention are characterised in the dependent claims or are evident from the following description of preferred embodiments on the basis of the drawings.

(2) FIG. 1 is a schematic diagram of an inventive coating device with an atomiser with an integrated colour changer and an additional separate colour changer;

(3) FIG. 2 is a modification of the coating device according to FIG. 1;

(4) FIG. 3 is a perspective view of an inventive painting robot with the coating device shown in FIG. 1;

(5) FIG. 4 is a modification of the embodiment according to FIG. 2 with an external colour changer which has only one paint outlet;

(6) FIG. 5 is a flow chart illustrating the operation of the embodiment in accordance with FIG. 4;

(7) FIG. 6A is a geared pump of conventional design which may be used to supply high-runners or low-runners;

(8) FIG. 6B is a geared pump of novel design, with a plurality of pumping chambers, pairs of gearwheels located therein and a common drive shaft to drive said pairs of gearwheels;

(9) FIG. 7 is a cutaway perspective view of the geared pump in accordance with FIG. 6B;

(10) FIG. 8 is a perspective view of the geared pump in FIG. 7;

(11) FIG. 9 is a longitudinal section through the geared pump in accordance with FIGS. 7 and 8;

(12) FIG. 10 is a cross-section of the geared pump in accordance with FIGS. 7 to 9 and

(13) FIG. 11 is a cross-section through an inventive atomiser with an internal colour-changer valve assembly.

(14) FIG. 1 is a schematic diagram of an inventive painting system which may be used for the mass painting of motor vehicle bodies and their attachments.

(15) For this purpose the inventive coating device has an atomiser 1, which is in the form of a high-speed rotary atomiser in this embodiment and which has a bell plate 2 as an application element.

(16) The atomiser 1 has an integral colour changer valve assembly 3 with four paint valves F1, F2 F3, F4 to supply high runners. The paint valves F1-F4 of the integral colour-changer valve assembly 3 are each connected to a paint inlet 4-7, wherein the paint inlets 4-7 are available on the connecting flange of the atomiser 1.

(17) A metering device 8 is connected to the paint inlets 4-7 of the integral colour-changer valve assembly 3, which is structurally separate from the atomiser 1 and which has a volumetric metering pump 9-12 for each of the paint inlets 4-7 and a common drive motor 13.

(18) The high runners are fed to the metering device 8, as the integral colour-changer valve assembly 3 only has low colour-change losses due to the short train of pipes between the integral colour-changer valve assembly 3 and the bell plate 2, and requires a short colour change time.

(19) The integral colour-changer valve assembly 3 is therefore connected to the bell plate 2 through a common main needle valve HN, which is only shown in diagrammatic form in the drawing.

(20) A short flushing valve KS is also on a branch between the main needle valve HN and the bell plate 2, ending in a flushing connection V on the connection flange of the atomiser 1. The bell plate 2 can be flushed with a known flushing agent through the flushing connection V and the short flushing valve KS.

(21) The common node at the outlet of the integral colour-changer valve assembly 3 and the inlet of the main needle valve HN is also connected to a pulsed air connection provided on the connecting flange of the atomiser 1 through a pulsed air valve PL. The train of pipes of the atomiser 1 can be cleaned with pulsed air through the pulsed air valve PL, which is itself also known.

(22) A flushing agent valve VV also branches off from the common node of the colour-changer valve assembly 3 and the main needle valve HN, ending at the flushing connection V on the connection flange of the atomiser 1, so that conventional solvent flushing is possible through the flushing agent valve VV.

(23) In addition to the colour-changer valve assembly integrated into the atomiser 1, the inventive coating system has a separate colour-changer valve assembly 14 which is structurally separate from the atomiser and which may take a conventional form, as described, for example, in EP 1 502 657 A2. At this point it need only be mentioned that the external colour-changer valve assembly 14 is configured as an A/B colour changer and has two paint outlets which are separately flushable, meaning that the colour changing time and colour changing losses can be reduced.

(24) On the outlet side, the external colour-changer valve assembly 14 is connected to a metering device 15, which has a volumetric metering pump 16, 17 for each of the two paint outlets of the external colour-changer valve assembly 14, whereby the two metering pumps 16, 17 are each driven independently of each other by a drive motor 18, 19.

(25) In addition to the paint inlets 4-7 for the integral colour-changer valve assembly 3, the atomiser 1 has two separate paint inlets 20, 21, which are connected to the main needle valve HN through separately-actuatable paint valves FA, FB, to connect the atomiser 1 to the metering device 15.

(26) The external colour-changer valve assembly 14 is supplied with low runners, for which the longer colour change time and greater colour change losses play a less significant role.

(27) A recirculation valve RA, RB is on a branch off the additional paint inlets 20, 21 for the external colour-changer valve assembly 14, whereby the two recirculation valves RA, RB in this embodiment are structurally integrated into the atomiser 1. In this way the paint inlets 20, 21 can be flushed as far as the atomiser 1.

(28) If high runners account for 65% of total capacity and colour change losses amount to 49 ml in the external colour-changer valve assembly and 5 ml in the internal colour-changer valve assembly 14, the inventive coating device described above facilitates a reduction in average colour change losses from 49 ml to 20.4 ml, corresponding to a saving of 28.6 ml.

(29) FIG. 2 shows a minor modification to the embodiment in FIG. 1, so reference is made to the above description to avoid repetition, whereby the same numbers are used for corresponding components.

(30) A peculiarity of this embodiment is that both the recirculation valves RA, RB are located outside the atomiser 1.

(31) FIG. 3 is a perspective view of two painting robots 22, 23, which may be moved linearly along a track 24, which is known. Both the painting robots 22, 23 each have a moveable frame 25 and two robot arms 26, 27, robot arm 26 being designated arm 1 and robot arm 27 being designated arm 2.

(32) A conventional robot wrist 28, which guides the atomiser 1, is fitted to the distal end of the robot arm 27.

(33) The metering device 8 (c.f. FIG. 1) for the colour-changer valve assembly 3 integrated into the atomiser 1 is mounted in robot arm 26 (arm 1), whilst the external colour-changer valve assembly 14 is mounted in robot arm 27 (arm 2).

(34) It must also be mentioned that the pulsed air valve PL and the flushing agent valve VV may also be located outside the atomiser 1, for example on robot arm 27 (arm 2). The changeover then takes place outside the atomiser 1.

(35) FIG. 4 shows a modification to the embodiment in FIG. 2, so reference is made to the above description to avoid repetition, whereby the same numbers are used for corresponding components.

(36) A peculiarity of this embodiment is that the external colour-changer valve assembly 14 is not configured as an A/B colour changer, but has only one paint outlet, which is associated with lower investment costs, a smaller installation space and lower weight.

(37) In this version, high-runners and low-runners are applied alternately, as shown in the flow chart in FIG. 5, so that there is enough time during the application of a high runner through the internal colour-changer valve assembly 3 to flush the external colour-changer valve assembly 14 and apply the next low runner to it under pressure. The longer colour changing time required by the external colour-changer valve assembly 14 then has no irritating effect, but production scheduling becomes more involved, in order to ensure that the atomiser 1 can apply high-runners and low runners alternately.

(38) FIG. 6A shows an embodiment of a geared pump 29 which may, for example, be used instead of the metering device 8 in FIG. 1 to supply the various paint inlets 4-7 of the atomiser 1 with the various high runners.

DETAILED DESCRIPTION

(39) The geared pump 29 has a plurality of pumping chambers 30-33, shown only in diagrammatic form here, each of which contains a pair of gearwheels, as is known, for example, from DE 600 09 577 T2.

(40) The individual pairs of gearwheels in pumping chambers 30-33 are driven by a motor 35 through a drive shaft 34. Clutches 36-39, facilitating mechanical disconnection, are located between the individual pumping chambers 30-33 and between the pumping chamber 30 and the motor 35.

(41) FIG. 6B shows a further, novel embodiment of a geared pump 29, whereby this embodiment is partially identical to that described above and shown in FIG. 6A, so reference is made to the above description of FIG. 6A to avoid repetition, the same numbers being used for corresponding components.

(42) A peculiarity of this embodiment is that the common drive shaft 34 for the pairs of gearwheels located in the individual pumping chambers 30-33 extends through the entire length of the geared pump 29.

(43) The individual clutches 36-39 do not facilitate mechanical disconnection of the drive shaft 34 in an axial direction in this case. Instead, the individual clutches 36-39 make it possible for the pairs of gearwheels located in the pumping chambers 30-33 to be engaged with or disengaged from the drive shaft 34 selectively.

(44) The structural design and method of operation of the geared pump 29 are described in more detail below, using FIGS. 7 to 10.

(45) It is thus evident from these drawings that the individual pumping chambers 30-33 are each formed by a central plate 40-43 and adjacent end plates 44-51, so that the individual pumping chambers 30-33 are behind one another in the axial direction of the drive shaft 34.

(46) For the sake of simplification, only five gearwheels 52-56 are shown in full in the cutaway three-quarter view in FIG. 7, although two gearwheels engaging with each other are located in each of the pumping chambers 30-33.

(47) In addition, the geared pump 29 has a draw key 57 for selective engagement of the pairs of gearwheels located in the pumping chambers 30-33 with the drive shaft 34, facilitating engagement of the drive shaft 34 with the individual pairs of gearwheels by means of locking elements 58-60.

(48) The geared pump 29 also has a shaft seal 61 and a bearing 62 in this embodiment.

(49) The compact size of this design of the geared pump 29 is advantageous, which is particularly important when the geared pump 29 is to be mounted in a robot arm.

(50) Finally, FIG. 11 is a schematic diagram of an inventive atomiser 63 with a bell plate 64 and a plurality of external electrodes 65 for electrostatic charging of the coating material to be applied.

(51) Here, the atomiser 63 has a flange assembly 66, a manifold 67, an elbow 68 and a forepart 69.

(52) The manifold 67 contains an internal colour-changer valve assembly 70, whilst a main needle vale 71 is located in the forepart 69. This has the advantage that if the manifold 67 is separated from the elbow 68 and forepart 69, only a few pipes will extend across the dividing line, entailing only minor contamination on separation.

(53) The invention is not restricted to the embodiments described above. On the contrary, a variety of alternatives and modifications is possible, also using the inventive concept and therefore being within the scope of protection.