FR3135004A1 - Welding machine. - Google Patents

Abstract

Welding machine The invention relates to a welding machine (1) of at least two parts to be welded, the welding machine (1) comprising at least one movable assembly (10) which comprises at least one pair of drive wheels intended to move said mobile assembly (10) relative to the parts to be welded, at least one welding head (14) comprising at least two welding wheels (16) capable of welding the parts to be welded, and at least one converter (18) which supplies a welding current to the welding head (14), the welding machine (1) comprising a cooling device (24) of the mobile assembly (10), the cooling device (24) comprising at least one cooling circuit (26) which runs through the mobile assembly (10). Figure 3

Description

Welding machine.

The present invention relates to welding devices comprising electrodes in the form of welding wheels, making it possible to weld parts to be welded together.

Current welding machines include drive wheels as well as welding wheels making it possible to weld the parts to be welded, as well as a drive member capable of rotating at least the drive wheels along parts to be welded. The welding wheels are supplied with electric current when the welding machine moves by means of an electric current unit, ensuring the welding of the parts to be welded. Current welding machines also include numerous elements ensuring the operation of the welding machine, such as a transformer necessary at least for the implementation of welding by the welding rolls.

During the operation of welding machines, the welding wheels but also other components of said machine, such as the transformer, heat up in particular under the effect of the current passing through them. Thus, it is usual for welding machines to include a cooling device to ensure cooling at least of the welding wheels and the transformer. Such a cooling device makes it possible in particular to circulate a heat transfer fluid as close as possible to the welding wheels and the transformer in order to limit their heating during their use.

However, one of the problems with current cooling devices relates in particular to the fact that they require a significant quantity of heat transfer fluid in order to ensure minimum cooling to the various components of the welding machine which heat up. Furthermore, the general cooling performance of current cooling devices can be improved. Indeed, current cooling devices offer a classic circulation of the heat transfer fluid within the welding machine, a circulation which does not make it possible to optimize the cooling of the welding machine.

Thus, the aim of the present invention is to provide a welding machine whose cooling device makes it possible to improve the cooling of its components by optimizing the use of the heat transfer fluid. We thus offer a welding machine which is more economical to use and whose cooling performance is improved.

The invention therefore relates to a welding machine for at least two parts to be welded, the welding machine comprising at least one mobile assembly which comprises at least one pair of drive wheels intended to move said mobile assembly relative to the parts to weld, at least one welding head comprising at least two welding wheels capable of carrying out a weld intended to join the parts to be welded by rolling the welding wheels against the parts to be welded, and at least one converter which supplies a current of welding with the welding head, the welding machine comprising a device for cooling the mobile assembly, the cooling device comprising at least one cooling circuit which runs through the mobile assembly and in which a heat transfer fluid circulates, said cooling circuit cooling comprising at least one common conduit from which extend at least a first branch and a second branch parallel to each other, the first branch passing through the welding wheels of the welding head and the second branch running through the converter.

The welding machine according to the invention can be used for example to weld two raised edges together and/or with an anchoring wing of a waterproof membrane constituting a wall of a storage and/or transport tank. cryogenic products such as liquefied natural gas.

To this end, the welding machine comprises at least the pair of drive wheels ensuring, by means of a drive member, the movement of the mobile assembly along the parts to be welded in a rectilinear welding direction, otherwise called the direction of advancement of the welding machine. The drive member may for example be an electric, hydraulic, pneumatic or even mechanical drive member. Preferably the drive member in the context of the invention is an electric motor.

The welding wheels make it possible to carry out the welding, by contact with at least one of the parts to be welded which can be at least one of the raised edges or the anchoring wing. More precisely, and according to a non-limiting example of the invention, when carrying out the welding of the parts to be welded, the movement of the welding machine relative to the parts to be welded causes the rotation of the welding wheels against the parts to be welded and an electric current supplied by a power supply unit and passing through said welding wheels makes it possible to form a weld bead on said parts to be welded. It is also understood that the electrical power supply unit makes it possible to supply an electric current to the drive member of the drive wheels, such that the latter are rotated.

In order to limit the heating of the mobile assembly of the welding machine during its use, that is to say during the welding of the parts to be welded, the welding machine includes the cooling device. The cooling device according to the invention then makes it possible to cool on the one hand the welding wheels, and on the other hand the converter, by means respectively of the first branch and the second branch of the cooling circuit swept by the heat transfer fluid . We then understand that the cooling of the welding wheels and the converter takes place in parallel and thus allows the latter to be cooled by the heat transfer fluid with an identical temperature. The use of the heat transfer fluid is thus optimized by optimizing its circulation in the mobile assembly so that at least the converter and the welding wheels are adequately cooled without requiring an additional heat transfer fluid.

According to one characteristic of the invention, the mobile assembly comprises at least one transformer, the common conduit of the cooling circuit running through at least the transformer.

The transformer of the mobile assembly corresponds to the element, among the welding wheels and the converter, which must undergo the greatest cooling by the heat transfer fluid. Thus, one of the advantages of the invention is to allow the heat transfer fluid to initially cool the transformer, the heat transfer fluid then having its lowest temperature, then subsequently to cool with the heat transfer fluid at the outlet of the common conduit , the converter and the welding wheels which require a lower heat transfer fluid temperature. The circulation of the heat transfer fluid is thus optimized according to the cooling needs of each of the transformer, the converter and the welding wheels, these not requiring the same temperatures of the heat transfer fluid.

According to a characteristic of the invention, each of the first branch and the second branch comprises an inlet and an outlet in a direction of circulation of the heat transfer fluid in the cooling circuit, said cooling circuit comprising at least one intermediate conduit fluidly connected at the exit of at least the first branch.

It is further understood that the inputs of each of the first branch and the second branch are fluidly connected to an output of the common conduit.

According to one characteristic of the invention, the welding machine comprises a carriage distant from the mobile assembly and connected to it by a harness, the carriage comprising at least one heat transfer fluid reservoir, a pump and a refrigeration unit comprising a heat exchanger making it possible to capture calories from the heat transfer fluid via a working fluid which circulates in the refrigeration unit.

The cart also includes the power supply unit for the welding machine. We also understand that the heat exchanger ensures the cooling of the heat transfer fluid in the tank such that it has an adequate temperature at the tank outlet.

According to one characteristic of the invention, the bundle comprises at least one inlet pipe and one outlet pipe connected to the cooling circuit of the mobile assembly, the inlet pipe being fluidly connected to an inlet of the common pipe, and the outlet pipe being fluidly connected at least to the outlet of the second branch. Preferably, the outlet pipe is also linked to the intermediate pipe receiving the heat transfer fluid flowing from the outlet of the first branch.

It is also understood that the inlet pipe and the outlet pipe are both connected to the reservoir of the cooling device, carried by the trolley.

According to one characteristic of the invention, the welding machine comprises a control unit capable of receiving values of at least one parameter relating to the cooling device, the control unit being configured to control the cooling device in function at minus of said parameter.

According to an example of the invention, the parameter relating to the cooling device is a temperature of the heat transfer fluid in the reservoir of the cooling device.

The control unit according to the invention can be carried by the carriage or by the mobile assembly. According to a preferred embodiment of the invention, the control unit is carried by the mobile assembly of the welding machine. More particularly, the control unit and the converter are carried by the same printed circuit board arranged on the mobile assembly.

According to one characteristic of the invention, the welding machine comprises at least one means for determining the temperature of the heat transfer fluid in the reservoir of the cooling device.

Thus, according to an example of the invention, the determination means is placed in the tank and makes it possible to detect temperature values of the heat transfer fluid within the latter.

According to one characteristic of the invention, the control unit is capable of controlling at least partly the operation of the converter.

According to one characteristic of the invention, the control unit is able to receive values of at least one parameter relating to the converter so as to control it.

According to an example of the invention, the control unit is capable of receiving values of at least one parameter relating to the transformer so as to control the operation of the welding machine, and more particularly of the power supply unit. electrical of the welding machine, so as to control the electrical supply to at least the welding rolls and the drive member of the drive rolls as a function of said values of the parameter relating to the transformer.

According to an example of the invention, the parameter relating to the transformer and/or the converter is a temperature of the latter. Thus, by controlling the transformer and/or converter we mean controlling at least their temperature. In addition, the control unit can also control the intensity of the current generated by the transformer and/or the converter, that is to say the welding current.

According to one characteristic of the invention, the welding machine comprises at least a first sensor which detects temperature values of the transformer and/or a second sensor which detects temperature values of the converter, the control unit being configured to control the transformer and/or the converter as a function of the temperature values detected by the first sensor and/or the second sensor.

It is understood that the control unit is able to control the electrical power supply to at least the welding wheels and the drive member of the drive wheels as a function of the temperature values detected by the first sensor. In other words, the control unit stops the welding of the parts to be welded and the advancement of the mobile assembly of the welding machine along the parts to be welded as a function of the temperature values of the transformer detected by the first sensor.

According to one characteristic of the invention, the cooling device is configured so that the flow rate of the heat transfer fluid within the common conduit is at least equal to 6L/min. This value is only an example and depends in particular on the type of transformer used and the power of the latter.

We understand that the pump of the cooling device makes it possible to provide a flow rate of the heat transfer fluid at the tank outlet, and thus in the common conduit, at least equal to 6L/min.

The invention also relates to a method of controlling the welding of at least two parts to be welded by a welding machine according to any of the preceding characteristics, the method of controlling the welding comprising at least:

- a step of reception by the control unit of at least one temperature value relating to the cooling device;

- a step of comparing the at least one temperature value received with respect to a reference threshold of said parameter relating to the cooling device;

- a step of controlling the cooling device by comparing the at least one temperature value received with the reference threshold of said parameter.

According to one aspect, controlling the cooling device may consist of putting it into operation with a view to cooling the mobile assembly when said received temperature value is equal to or greater than said reference threshold.

According to another aspect, controlling the cooling device can consist of stopping it when said received temperature value is lower than said reference threshold.

It is understood that prior to the reception step, the control method may include a step of entering at least the reference threshold relating to the temperature of the cooling device, in a control interface connected to the control unit. The control interface is for example carried by the carriage of the welding machine and transmits the at least one reference threshold to the control unit so that it carries out the comparison step.

By reference threshold we mean a maximum value for the parameter.

Furthermore, the control step makes it possible to implement the cooling of the heat transfer fluid in the tank by the heat exchanger. In other words, when the temperature value detected by the determination means and received by the control unit is equal to or greater than the reference threshold of said parameter, the control unit implements the cooling of the circulating heat transfer fluid in the mobile assembly via the heat exchanger of the refrigeration unit carried by the trolley.

According to one characteristic of the invention, during the reception step, the control unit receives at least one value of a parameter relating to the transformer and/or the converter, then during the comparison step l the control unit compares the at least one value received with respect to a reference threshold value of said at least one parameter, then in the control step the control unit controls the operation of the transformer and/or converter in operation comparing the received value of said parameter with respect to the reference threshold value. In other words, the control unit controls at least the temperature of the converter during the control step.

According to an example of the invention, during the reception step, the control unit receives at least one value of the parameter relating to the transformer, then during the comparison step the control unit compares the at least one value received in relation to a reference threshold value of said at least one parameter, then in the control step the control unit controls the power supply unit which supplies an electric current at least to the welding wheels and to the drive wheel drive member as a function of the comparison of the received value of said parameter in relation to the reference threshold value. It is therefore understood that the control unit stops the electrical supply at least to the mobile assembly as a function of the temperature value detected by the first sensor and relating to the temperature of the transformer, in relation to its associated reference threshold value. .

It is understood that the input step, prior to the reception step, can include the input of at least one reference threshold value of the parameter relating to the transformer and/or the converter in the control interface. In the example of the invention, the reference threshold value corresponds to a temperature value not to be exceeded, for example 30°C.

It is further understood that during the control step, the control unit activates the cooling device to cool the converter when the at least one temperature value received from the parameter relating to the converter is equal to or greater than the reference threshold value of said parameter. Such control thus makes it possible to avoid overheating of the converter when using the welding machine.

Furthermore, it must be understood that the control step implemented by the control unit and during which it stops at least the electrical power supply to the welding rolls and the drive member of the welding rolls training, when the at least one temperature value received from the parameter relating to the transformer is equal to or greater than the reference threshold value of said parameter, at least makes it possible to avoid overheating of the transformer and more generally of the mobile assembly.

According to one characteristic of the invention, the control method is operated continuously between a starting position of the mobile assembly and an arrival position of said mobile assembly. The arrival position corresponds to a position where the mobile assembly stops moving on the parts to be welded.

Other characteristics, details and advantages of the invention will emerge more clearly on reading the description given below for information purposes in relation to the drawings in which:

is a general perspective view of a storage and/or transport tank for cryogenic products, comprising at least two welded parts constituting a waterproof membrane of the tank;

is a perspective view of a welding machine according to the invention, capable of welding the two parts to be welded of the ;

is a perspective view of the welding machine of the showing a cooling device according to the invention;

is a flowchart of the steps of a process for controlling the welding of parts to be welded by the welding machine according to the invention.

It should first be noted that if the figures present the invention in detail for its implementation, these figures can of course be used to better define the invention, if necessary. It should also be noted that these figures only show examples of embodiments of the invention. Finally, the same references designate the same elements in all of the figures.

Figures 2 and 3 illustrate a welding machine 1 configured to move along at least two parts to be welded 2. More precisely, the parts to be welded 2 constitute a waterproof membrane 4 of a wall 6 tank 8 for storing and/or transporting cryogenic products, for example liquefied natural gas and visible at .

The welding machine 1 comprises at least one mobile assembly 10 which has a substantially parallelepiped shape and which extends in a direction of main elongation P parallel to a longitudinal direction L of the welding machine 1. The mobile assembly 10 of the welding machine 1 is intended to move along the parts to be welded 2 and comprises for this purpose at least one pair of drive wheels 12 intended to move said welding machine 1 relative to the parts to be welded. More particularly the drive wheels 12 are arranged in contact with the parts to be welded 2 by means of a pressurizing device 13, such as for example a jack, and a drive member, not visible, makes it possible to drive them in rotation against the parts to be welded 2, thus moving the mobile assembly 10 of the welding machine 1. The drive member can for example be an electric, hydraulic, pneumatic or even mechanical drive member. Preferably, the drive member in the context of the invention is an electric motor. According to the example of the invention illustrated, the mobile assembly 10 of the welding machine 1 comprises two pairs of drive wheels 12 arranged opposite each other in the direction of main elongation P of the mobile assembly 10.

The mobile assembly 10 further comprises a welding head 14 comprising at least two welding wheels 16 capable of carrying out a weld intended to join the parts to be welded by rolling said welding wheels 16 against the parts to be welded. In the illustrated example of the invention, the welding head 14 is arranged between the two pairs of drive wheels 12 in the direction of main elongation P of the mobile assembly 10. The welding head 14 also comprises at least one device 15 for pressurizing the welding wheels 16 against the parts to be welded 2, the pressurizing device 15 being able to take the form, for example, of cylinders.

According to the invention, the mobile assembly 10 also comprises at least one electrical converter 18, hereinafter called converter, intended to supply a welding current to the welding head 14. In other words, the converter 18 makes it possible to transform an alternating current supplied by a power supply unit 20 of the welding machine 1 in order to power at least the welding wheels 16, the converter 18 making it possible to transform the 50Hz alternating current of the power supply unit 20 into a 1000 Hz alternating current, necessary for the welding wheels 16. The converter notably comprises at least one rectifier bridge, a capacitor and an inverter. The electric current at the converter output is directed to a transformer/rectifier which will transform the 1000Hz alternating current into a pulsed electric current sent to the welding wheels 16.

Still according to the invention, the mobile assembly 10 comprises at least one transformer 22 intended to receive a high voltage and low intensity current at the output of the converter 18 and to transform it into a low voltage and high intensity current to supply it to the less to the welding wheels 16.

We then understand from the above that the current at the output of the electrical power supply unit 20 is directed beforehand into the converter 18 in order to pass from an alternating current of 50 HZ to an alternating current of 1000 HZ then is directed towards the transformer 22 in order to lower its voltage and increase its intensity.

The welding machine 1 also comprises at least one cooling device 24 of the mobile assembly 10. More particularly, the cooling device 24 is composed of a cooling circuit 26, visible at the , circulating a heat transfer fluid as close as possible to the welding wheels 16, the cooling device 24 further comprising a reservoir 28 of heat transfer fluid, a pump 30 and a refrigeration unit 32 which comprises at least one heat exchanger 33. Such cooling device 24 makes it possible in particular to avoid overheating at least of the welding wheels 16 during operation of the welding machine 1. The cooling device 24 will be detailed later in the description.

The welding machine 1 also includes a carriage 34 visible in Figures 2 and 3, distant from the mobile assembly 10, and connected to the latter by a beam 36. The beam 36 comprising, among other things, the electrical and hydraulic connections necessary for operation of the mobile assembly 10. The carriage 34 is in particular configured to carry elements of the welding machine 1, for example the electrical power supply unit 20 of the welding machine 1 mentioned previously or even the tank 28, the pump 30 and the refrigeration unit 32 of the cooling device 24.

The function of the electrical power supply unit 20 is to deliver an electric current at least to the drive member of the drive wheels 12 so that they are rotated so as to move the mobile assembly 10 from the welding machine 1, and the welding wheels 16, through the converter 18 and the transformer 22 as mentioned previously, so that they are able to carry out the welding of the parts to be welded 2 when they are crossed by this Electric power.

The cooling device 24 according to the invention, particularly visible at the , comprises at least one inlet pipe 38 and an outlet pipe 40 which extend in the bundle 36 and which are intended to fluidly connect the reservoir 28 of heat transfer fluid to the cooling circuit 26 traversed by the heat transfer fluid which is extends into the mobile assembly 10 of the welding machine 1. It is further understood that the pump 30 of the cooling device 24 makes it possible to distribute the heat transfer fluid in the inlet 38 and outlet 40 pipes and in the cooling circuit 26. The refrigeration unit 32 also makes it possible to cool the heat transfer fluid in the tank 28 by means of a heat exchange between the heat transfer fluid and a working fluid, within the heat exchanger 33. According to an example of the invention, the temperature of the heat transfer fluid in the tank 28 is between 20°C and 30°C.

The cooling circuit 26 which runs through the mobile assembly 10 and in which the heat transfer fluid circulates comprises in particular a common conduit 42 from which extend at least a first branch 44 and a second branch 46, in parallel to each other. to the other. We therefore understand that the first branch 44 and the second branch 46 are fluidly connected to the common conduit 42. As visible in the , the common conduit 42 runs through at least the transformer 22 such that the heat transfer fluid that it transports cools the latter. Furthermore, according to the invention, the first branch 44 runs through at least the welding wheels 16 of the welding head 14 and the second branch 46 runs through at least the converter 18. Thus, it is understood that the heat transfer fluid is intended to cool first the transformer 22 then cooling in parallel the converter 18 and the welding wheels 16 at the outlet of the common conduit 42.

According to one characteristic of the invention, the cooling device 24 is configured so that the flow rate within the common conduit is at least equal to 6L/min. In other words, the pump 30 of the cooling device 24 is configured to provide a flow rate to the heat transfer fluid leaving the tank of at least 6L/min.

The cooling circuit 26 also comprises an intermediate conduit 48 for the heat transfer fluid. More precisely, we define an inlet 50a, 50b and an outlet 52a, 52b of each of the first branch 44 and the second branch 46 following a direction of circulation of the heat transfer fluid in the cooling circuit 26, the intermediate conduit 48 being fluidly connected at least to the outlet 52a of the first branch 44. Furthermore, the outlet 52b of the second branch 46 is connected directly to the outlet pipe 40 mentioned above. It is also understood that the inputs 50a, 50b of each of the first branch 44 and the second branch 46 are connected to an output 52c of the common conduit 42.

As visible at , the inlet pipe 38 of the cooling device 24 is fluidly connected on the one hand to the reservoir 28 and on the other hand to an inlet 50c of the common conduit 42 and the outlet pipe 40 is fluidly connected to an outlet 52d of the conduit intermediate 48, at the outlet 52b of the second branch 46 of the cooling circuit 26 and at the reservoir 28.

We understand from the above that the heat transfer fluid leaving the tank 28, having a temperature between 20°C and 30°C, first travels through the transformer 22 for which it captures calories in order to cool it so that the heat transfer fluid has a temperature between 20°C and 60°C at the output of transformer 22, then is directed in parallel towards the welding wheels 16 and the converter 18 in order to cool them. This makes it possible to optimize the use of the heat transfer fluid by directing it beforehand towards the transformer 22 which requires a higher cooling temperature than the welding wheels 16 and the converter 18.

According to one characteristic of the invention, the welding machine 1 comprises at least one control unit 54, visible at the , capable of receiving values of at least one parameter relating to the cooling device 24, the control unit 54 being configured to control the cooling device 24 as a function of at least said parameter. By controlling, we mean the fact that the control unit 54 is able to process the values that it receives from at least one parameter relating to the cooling device 24 by comparing them in particular to a reference threshold of said parameter. According to the invention, the reference threshold can correspond to a maximum value of the parameter.

The control unit 54 is here carried by the mobile assembly 10 of the welding machine 1. According to a particular example of the invention, the control unit 54 and the converter 18 are carried by the same printed circuit board arranged on the mobile assembly 10.

According to the invention, the parameter relating to the cooling device 24 comprises at least one temperature of the heat transfer fluid in the reservoir 28 of the cooling device 24. Thus, the welding machine 1 comprises at least one means 56 for determining a value of the temperature of the heat transfer fluid in the tank 28 of the cooling device 24, the determination means 56 being disposed in said tank 28. According to an example of the invention, the determination means 56 is a sensor comprising at least one temperature probe. temperature.

According to another aspect of the invention, the control unit 54 is capable of controlling at least in part the operation of the electrical power supply unit 20 and/or the converter 18, visible at the . In other words, the control unit 54 is capable of receiving values of at least one parameter relating to the transformer 22 and/or the converter 18 so as to respectively control the electrical power supply to at least the welding wheels and the drive wheel drive member and/or control the converter. By controlling here we understand the fact that the control unit is able to authorize and/or stop the electrical supply and/or the cooling of the converter 18 as a function of the values received from at least one parameter relating to the latter.

Thus, the welding machine 1, visible at the , comprises at least a first sensor 58a which detects a temperature value of the transformer 22 and/or a second sensor 58b which detects a temperature value of the converter 18, said temperature values being sent to the control unit so that it treats them. In particular, the control unit receives the temperature values detected by the first sensor 58a and/or the second sensor 58b and compares them to reference values of said parameters in order to control them as mentioned above.

According to an example of the invention, the control unit stops the electrical supply to at least the welding wheels 16 and the drive member of the drive wheels 12 by the electrical supply unit 20, when the values received of the parameter relating to transformer 22 are greater than the reference value of said parameter.

A process for controlling the welding of parts to be welded will now be described in relation to Figures 2 to 4.

The welding process comprises at least one input step 100 during which the reference threshold of at least one parameter of the cooling device 24 is entered in a control interface 60 connected to the control unit 54. In the example of the invention, the parameter of the cooling device 24 corresponds to the temperature of the heat transfer fluid within the reservoir 28, the associated reference threshold can then be a temperature value or a range of temperature values. According to an example of the invention, the reference threshold of the parameter of the cooling device 24, here the reference threshold of the temperature of the heat transfer fluid in the tank 28, is 30°C. The input step 100 can also include the input of the reference values for the parameters relating to the transformer 22 and/or the converter 18 as mentioned previously. According to the example of the invention, the parameters relating to the transformer 22 and/or the converter 18 correspond to temperature values of the latter and thus, their associated reference threshold value corresponds to a temperature value. For example, the reference threshold value associated with the transformer is a value of 80°C and the associated reference threshold value for the converter is a value of 100°C.

In order to enter the at least one reference threshold and/or reference threshold value, the welding machine 1 comprises the control interface 60, carried by the carriage 34, and in which an operator can proceed to the step of input 100. We then understand that the control interface 60 is configured to communicate with the control unit 54 carried by the mobile assembly 10 in order to provide it with at least one reference threshold and/or reference threshold value .

Subsequently, the control method comprises a step 200 of reception by the control unit 54 of at least one temperature value relating to the cooling device 24. More particularly, during this step, the control unit 54 receives at least one temperature value of the heat transfer fluid contained in the reservoir 28 and detected by the determination means 56 mentioned above. Furthermore, during the reception step, the control unit 54 can also receive at least one value of one of the parameters relating to the transformer 22 and/or the converter 18. In other words, the unit control unit 54 receives at least one temperature value relating to the transformer 22 and/or the converter 18 detected by the first sensor 58a and/or the second sensor 58b.

Once the reception step 200 has been carried out, the method implements a comparison step 300 of the at least one temperature value relating to the cooling device 24 received by the control unit 54 with the reference threshold of said parameter . Likewise, the comparison step 300 may include the comparison by the control unit 54 of the at least one temperature value received in relation to the transformer 22 and/or the converter 18, with the associated reference threshold value. .

It is understood that as long as the temperature value is lower than the reference threshold value, the pump circulates the heat transfer fluid in the cooling circuit and it can be maintained at a temperature lower than the threshold value by heat exchange. with the surrounding air of the inlet and outlet pipes 38, 40 and/or thanks to the fact that the tank 28 has a large volume of heat transfer fluid which makes it possible to delay the start-up of the refrigeration unit 32.

Finally, once the comparison step 300 has been carried out, the control unit 54 implements at least one control step 400 of the cooling device 24 by comparing the temperature value received with the reference threshold value. More precisely, when the temperature value received, relating to the temperature of the heat transfer fluid in the tank 28, is equal to or greater than the reference threshold, the control unit 54 implements the operation of the refrigeration unit 32 which comprises the heat exchanger 33 so that the latter cools the heat transfer fluid by capturing its calories via the working fluid which circulates in the refrigeration unit 32.

Likewise, at the end of the comparison step 300, the control unit 54 can, during the control step 400, control the operation of the converter 18 as a function of the temperature value received. More precisely, when the temperature value relating to the converter 18, received by the control unit 54, is equal to or greater than its associated reference threshold value, the control unit 54 puts the cooling device into operation, and more particularly the operation of the refrigeration unit, so as to cool the converter 18. Such operation makes it possible in particular to avoid overheating of these components and ultimately premature wear of them and of the welding machine 1.

Furthermore, at the end of the comparison step 300, the control unit 54 can, during the control step 400, control the operation of the electrical supply unit 20, that is to say -say at least the stopping of the electrical supply of the welding wheels 16 and of the drive member of the drive wheels 12, when the temperature value relating to the transformer 22 received by the control unit 54 is equal to or greater than its associated reference threshold value.

At the end of the control step 400, the control unit 54 repeats the control process at least at the start of the reception step 200 or at the entry step 100 if new thresholds or reference values must be entered.

It is further understood that when the comparison step 300 concludes that the temperature value of the heat transfer fluid is lower than the reference threshold, the control unit 54 performs the reception step again without going through the control step 400. Likewise, when the comparison step 300 concludes that the temperature value of the transformer and/or the converter is lower than the reference threshold value, the control unit 54 returns to the reception step 200 without performing the control step 400.

We therefore understand that the control process is operated continuously between a starting position of the mobile assembly 10 and an arrival position of said mobile assembly 10 of the welding machine 1 relative to the parts to be welded.

It should also be considered that the functionalities of the control unit 54 according to the invention are not limited to those which have just been described and that the control unit 54 can control other parameters of the cooling device 24 and the converter 18. The functionalities described of the control unit 54 are non-limiting examples of the invention.

The invention as it has just been described cannot, however, be limited to the means and configurations exclusively described and illustrated, and also applies to all equivalent means or configurations and to any combination of such means or configurations.

Claims (12)

Welding machine (1) of at least two parts to be welded (2), the welding machine (1) comprising at least one mobile assembly (10) which comprises at least one pair of drive wheels (12) intended to move said mobile assembly (10) relative to the parts to be welded (2), at least one welding head (14) comprising at least two welding wheels (16) capable of carrying out a weld intended to join the parts to be welded (2) together ) by rolling the welding wheels (16) against the parts to be welded (2), and at least one converter (18) which supplies a welding current to the welding head (14), the welding machine (1) comprising a cooling device (24) of the mobile assembly (10), the cooling device (24) comprising at least one cooling circuit (26) which runs through the mobile assembly (10) and in which a heat transfer fluid circulates, said cooling circuit (26) comprising at least one common conduit (42) from which extend at least a first branch (44) and a second branch (46) parallel to each other, the first branch (44) passing through the welding wheels (16) of the welding head (14) and the second branch (46) passing through the converter (18). Welding machine (1) according to the preceding claim, in which the mobile assembly (10) comprises at least one transformer (22), the common conduit (42) of the cooling circuit (26) passing through at least the transformer (22). . Welding machine (1) according to any one of the preceding claims, in which each of the first branch (44) and the second branch (46) comprises an inlet (50a, 50b) and an outlet (52a, 52b) following a direction of circulation of the heat transfer fluid in the cooling circuit (26), said cooling circuit (26) comprising at least one intermediate conduit (48) fluidly connected to the outlet (52a) at least of the first branch (44). Welding machine (1) according to any one of the preceding claims, comprising a carriage (34) spaced from the mobile assembly (10) and connected to it by a beam (36), the carriage (34) comprising at least a reservoir (28) of heat transfer fluid, a pump (30) and a refrigeration unit (32) comprising a heat exchanger (33) making it possible to capture calories from the heat transfer fluid via a working fluid which circulates in the refrigeration unit ( 32). Welding machine (1) according to any one of the preceding claims, comprising a control unit (54) capable of receiving values of at least one parameter relating to the cooling device (24), the control unit (54 ) being configured to control the cooling device (24) as a function of at least said parameter. Welding machine (1) according to the preceding claim, comprising at least one means (56) for determining the temperature of the heat transfer fluid in the tank (28) of the cooling device (24). Welding machine (1) according to any one of claims 5 or 6, in which the control unit (54) is capable of controlling at least partly the converter operation (18). Welding machine (1) according to the preceding claim in combination with claim 2, comprising at least a first sensor (58a) which detects temperature values of the transformer (22) and/or a second sensor (58b) which detects values temperature of the converter (18), the control unit (54) being configured to control the transformer (22) and/or the converter (18) as a function of the temperature values detected by the first sensor (58a) and/or the second sensor (58b). Welding machine (1) according to any one of the preceding claims, in which the cooling device (24) is configured so that the flow rate of the heat transfer fluid within the common conduit is at least equal to 6L/min. Method for controlling the welding of at least two parts to be welded (2) by a welding machine (1) according to any one of the preceding claims in combination with any one of claims 5 to 9, the method for controlling the welding comprising at least:

• a step of reception (200) by the control unit (54) of at least one temperature value relating to the cooling device (24);
• a step of comparing (300) the at least one temperature value received with respect to a reference threshold of said parameter relating to the cooling device (24);
• a step (400) of controlling the cooling device (24) by comparing the at least one temperature value received with respect to the reference threshold of said parameter.

Control method according to the preceding claim in combination with claim 8, in which during the reception step (200), the control unit (54) receives at least one value of a parameter relating to the transformer (22 ) and/or to the converter (18), then during the comparison step (300) the control unit (54) compares the at least one value received with respect to a reference threshold value of said at least one parameter, then in the control step (400) the control unit (54) controls the operation of the transformer (22) and/or the converter (18) based on the comparison of the received value of said parameter in relation to the reference threshold value. Control method according to any one of claims 10 or 11, in which the method is operated continuously between a starting position of the mobile assembly (10) and an arrival position of said mobile assembly (10).