FR3090066A1 - Rotating fluidic connection for plastic container manufacturing machine - Google Patents

Abstract

The invention relates to a rotating fluid connection (1) for the transmission of a fluid between a frame and an assembly movable relative to the frame in a machine (2) for manufacturing plastic containers, comprising: - a body (3) integral with the frame and defining a fluid chamber (7) intended to receive a fluid from at least one channel formed in the frame; - a hollow shaft (4) integral with the movable assembly, and mounted in the body (3); - at least one O-ring (5) intended to prevent a flow of fluid between the hollow shaft (4) and the body (3); - means (6) for friction intended to cooperate with the O-ring (5), characterized in that the O-ring (s) (5) are carried by the hollow shaft (4) and the friction means (6) are carried by the body (3) . Figure for the abstract: Figure 1

Description

Description

Title of the invention: Rotating fluidic connection for a machine for manufacturing plastic containers

The field of the invention is that of the design and manufacture of machines for the manufacture of plastic containers, in particular by blow molding or stretch blow molding.

More specifically, the invention relates to a rotating fluid connection located between a frame of the machine and a movable assembly relative to the frame, this rotating fluid connection allowing the passage of a fluid from the frame to the assembly turning.

[0003] Such fittings are widely known and include:

- A body integral with the frame and defining a fluid chamber intended to receive a fluid from at least one channel formed in the frame, the body having at least one opening opening into the fluid chamber;

a hollow shaft secured to the movable assembly, mounted in the body through the opening, the hollow shaft being movable in rotation relative to the body and having at least one lumen to allow fluid communication between the hollow shaft and the fluid chamber;

- at least one O-ring having a friction surface interposed between the opening and the shaft, and intended to prevent a flow of fluid between the shaft and the body at the level of the opening;

- friction means intended to cooperate with the friction surface of the O-ring to help prevent a flow of fluid between the shaft and the body at the opening.

For this type of swivel joint, the O-ring is secured to the body and the friction means are secured to the shaft.

The friction means can for example take the form of a coating applied directly to the shaft, for example a coating of chromium oxide or chromium carbide type, or of a ring mounted on the shaft.

[0006] During the use of the machine, the friction of the friction surface of the O-ring on the friction means causes the friction means to heat up.

Therefore, the friction means heat up and can eventually deteriorate or, in the worst case, completely disappear.

This degradation is all the more important since the fluid is air injected at a pressure of 40 bars, which further increases the heating of the friction means.

This then results in a passage of fluid between the shaft and the body at the opening. Therefore, a curative maintenance intervention is necessary, forcing the machine to stop and therefore the container production cycle to stop.

To prevent this, preventive maintenance can be provided, however these preventive maintenance always require the machine to stop and therefore the production to stop. These preventive maintenance are however frequent to anticipate the rapid damage of the friction means.

In addition, damage to the friction means generates poor concentricity between the shaft and the body and therefore a risk of deterioration of the shaft and / or the body, that is to say potentially a leak. of fluid.

Such fluid leakage is particularly detrimental to the manufacture of the containers and therefore to the production rate offered by the manufacturing machine.

In addition, such a leak can cause damage to the body and the shaft and therefore non-uniform wear of the body and / or the shaft in an accelerated manner.

The invention particularly aims to overcome the drawbacks of the prior art.

More specifically, the invention aims to provide a rotating fluid connection to improve container production cycles, and in particular to limit the downtime of container manufacturing machines for maintenance phases.

The invention also aims to provide such a rotating fluid connection which is easy to maintain.

The invention further aims to provide such a rotary fluid connection which is simple to manufacture.

These objectives, as well as others which will appear subsequently, are achieved thanks to the invention which relates to a rotating fluidic connection for the transmission of a fluid between a frame and an assembly movable relative to the frame in a plastic container manufacturing machine, comprising:

- A body integral with the frame and defining a fluid chamber intended to receive a fluid from at least one channel formed in the frame, the body having at least one opening opening into the fluid chamber;

a hollow shaft secured to the movable assembly, mounted in the body through the opening, the hollow shaft being mobile in rotation relative to the body and having at least one lumen to allow fluid communication between the hollow shaft and the fluid chamber;

- At least one O-ring having a friction surface interposed between the opening and the hollow shaft, and intended to prevent a flow of fluid between the hollow shaft and the body at the level of the opening;

- friction means intended to cooperate with the friction surface of the O-ring to contribute to preventing the flow of fluid between the shaft and the body at the opening, characterized in that the seal (s) O-rings are carried by the hollow shaft and the friction means are carried by the body.

Such a rotary fluid connection offers a better lifespan over time than those of the prior art. In fact, during the manufacture of the containers, the air injected at a pressure of around 40 bars causes, in addition to the movements of the shaft relative to the body, significant heating of the friction means when these cooperate with the friction surface of the O-ring.

The positioning of the friction means on the body thus makes it possible to be able to cool the friction means more effectively to prevent them from degrading too much and too quickly.

Indeed, it is possible to use the body to dissipate the rise in temperature of the friction means.

Preventive maintenance is then reduced, as is the downtime of the manufacturing machine for maintenance operations. It is thus possible to manufacture a larger number of containers at the same time than with machines provided with fluidic connections rotating according to the prior art.

Advantageously, the friction means are in the form of a ring mounted in the body.

Such a ring makes it possible to be able to replace only the friction means when these are worn, without replacing the hollow shaft.

Indeed, according to the prior art, it is known that the friction means are preferably made by a coating of chromium oxide or chromium carbide directly affixed to the hollow shaft.

Therefore, in the event of maintenance, it is necessary to completely replace the shaft in order to be able, in a step of maintenance of the shaft dissociated from the maintenance of the machine, to replace or recharge the chromium oxide coating. .

Thus, the maintenance time is limited and shortened compared to the prior art.

Preferably, the ring is mounted with radial clearance in a first shoulder of the opening.

This allows the ring a swiveling movement which compensates for any slight misalignment of the shaft relative to the body.

Furthermore, in the event of deformation of the shaft during operation of the machine, the clearance allows the ring to remain in permanent contact with the friction surface of the O-ring.

According to an advantageous embodiment, the ring carries a surface coating intended to cooperate with the friction surface of the O-ring.

The surface coating allows both to protect the ring and also to ensure the seal by cooperation with the O-ring.

Indeed, during the use of the machine for manufacturing plastic containers, the surface coating degrades. Thus, during the maintenance phases, it is only necessary to replace or recharge the surface coating.

In this case, the surface coating advantageously comprises at least one of the materials from:

- chromium oxide;

- chromium carbide.

Chromium oxide and chromium carbide are hard materials, making it possible to resist friction and in particular abrasion of the friction surface of the O-ring on the friction means. Thus, the degradation of the friction means, and in particular of the chromium oxide and / or chromium carbide coating, is reduced or limited in time.

Preferably, the rotary fluid connection comprises at least one bearing interposed between the body and the hollow shaft, outside the fluid chamber, to guide the rotation of the shaft relative to the body.

Such a bearing may, for example, be a ball bearing or a roller bearing making it possible, in addition to guiding, to facilitate the rotation of the hollow shaft in the body.

In addition, such a bearing makes it possible to avoid the generation of overheating between the body and the hollow shaft during the rotation of the hollow shaft relative to the body.

Advantageously, the body has at least one vent opening inside the body between the fluid chamber and the bearing. Such a vent allows, when the O-ring and / or the friction means are damaged, that the fluid escaping from the fluid chamber does not come, by its pressure, to deteriorate the bearings.

More specifically, if pressurized fluid were to pass between the O-rings and the friction means, this fluid would escape directly through the vents without exerting force on the bearings, a force applied by the fluid (at 40 bars) on the bearings which may cause their deterioration.

More specifically, the body has several vents distributed over the periphery of the body.

The multiplication of vents allows that in case of leakage between the O-rings and the friction means, the fluid can be removed from the swivel fitting quickly. Thus, any deterioration of the bearing or bearings is avoided, or almost.

According to another advantageous embodiment, the rotary fluid connection comprises at least one pin inserted in one of the vents, the pin having a first end coming into contact with the friction means to block them in rotation relative to the body .

Thus, the friction means are not driven by the O-ring which is integral with the hollow shaft. Thus, only the surface coating of the friction means wears out. The friction means are therefore not damaged prematurely.

Advantageously, the friction means comprise at least one notch for the reception of the first end of a pin.

The notches prevent the pins from degrading the friction means by exerting local pressure. In addition, the simple insertion of the first end of a pin into at least one of the notches makes it possible to block the friction means in rotation by form cooperation. This then strengthens the life of the friction means and of the rotary fluid connection.

Preferably, the body comprises cooling means.

These cooling means allow the body to be cooled so that it provides thermal transmission and therefore cooling of the friction means.

In this case, the cooling means are in the form of fins external to the body to allow cooling by dissipation, and / or comprise an internal fluid circuit intended to allow the circulation of a heat transfer fluid in the body .

These types of cooling means allow the use of a fluid external to that circulating in the rotary fluid connection, which allows heat to be removed from the body and therefore cooling of the friction means.

In addition, this contributes to improving the service life of the rotary fluid connection.

The invention also relates to a machine for manufacturing a plastic container by blow molding or stretch blow molding, comprising:

- a frame;

- an assembly movable relative to the frame;

- a rotating fluid connection for the transmission of a fluid between the frame and the mobile assembly, as described above.

Other features and advantages of the invention will appear more clearly on reading the following description of a preferred embodiment of the invention, given by way of illustrative and non-limiting example, and of the accompanying drawings among which :

[Fig.l] is a longitudinal sectional view of a rotating fluid connection according to the invention;

[Fig-2] is a schematic sectional view of an O-ring and friction means of the rotary fluid connection according to the invention;

[Fig.3] is a perspective view from above of a ring forming the friction means of the rotary fluid connection according to the invention.

Figure 1 illustrates a rotary fluid connection 1 according to the invention.

More particularly, the rotary fluid connection 1 allows the transmission of a fluid between a frame and a movable assembly of a machine 2 for manufacturing plastic containers.

The rotating fluidic connection 1 comprises:

- a body 3;

- a hollow shaft 4;

- at least one O-ring 5;

- Means 6 of friction.

The body 3 is intended to be secured to the frame, for example by ad hoc fixing means allowing removable fixing, or irreversibly.

The body 3 defines a fluid chamber 7 intended to receive a fluid from at least one channel formed in the frame. The fluid intended to come into the fluid chamber 7 is in particular air, at a pressure of 40 bars.

The body 3, as illustrated in Figure 1, has at least one opening 8 opening into the fluid chamber 7.

More specifically, the body 3 comprises two openings 8 intended to be crossed each by the hollow shaft 4 as described below.

The body 3 also includes a fluidic inlet 9 allowing the connection of the body 3 of the fluidic fitting 1 rotating to the channel formed in the frame.

More specifically, the fluid inlet 9 is in direct communication with the fluid chamber 7 of the body 3.

As illustrated in Figure 1, the body 3 takes substantially the form of a cylindrical part opening at its two ends through the openings 8. An axis X of rotation of the hollow shaft 4 can thus be defined passing through the center of each of the openings 8.

In other words, the body 3 is thus hollow and can be traversed right through along the axis X by the hollow shaft 4.

Furthermore, the two openings 8 also open into the fluid chamber 7.

The fluid inlet 9 is located between the two openings 8 and opens in a direction substantially perpendicular to the axis X of rotation of the hollow shaft 4.

According to the embodiment illustrated in Figure 1, the body 3 also includes means 10 for cooling.

These cooling means 10 are, according to a first embodiment, in the form of fins 11 external to the body 3, that is to say extending radially outward from the body 3. These fins 11 then allow the cooling of the body 3 by heat dispersion as described below, in particular by increasing the exchange surface of the body 3 relative to the ambient air, that is to say the air around machine 2.

According to another embodiment, the cooling means 10 are in the form of one or more pipes 12 forming a fluid circuit internal to the body 3, allowing the circulation of a heat transfer fluid in the body 3.

On each side of the fluid chamber 7, the body 3 has two first annular shoulders 13 intended to each receive the cooling means 10, as described below. The first shoulders 13 are oriented back to back, that is to say that they each open in an opposite direction.

As illustrated in Figure 1, the first shoulders 13 open opposite the fluid chamber 7.

The body 3 also includes two second annular shoulders 14. These two second annular shoulders 14 are each located on either side of the fluid chamber 7, and more precisely outside the first annular shoulders 13 along the X axis. The second shoulders 14 are also oriented back to back, that is, they each open in a direction opposite to the other direction. As illustrated in FIG. 1, the second shoulders 14 open opposite the fluid chamber 7.

In other words, the fluid chamber 7 is located between the first two annular shoulders 13, which are themselves located between the two second annular shoulders 14.

The body 3 also has vents 15 each opening into the body 3.

More particularly, the body 3 comprises a first series of vents 15 and a second series of vents 15. Each series of vents 15 is arranged in the form of a crown, on the external periphery of the body 3. It is therefore understood that each vent 15 opens both into the body 3 and outside of it.

The first series of vents 15 is located on a first side of the fluid chamber 7 between a first shoulder 13 and a second shoulder 14.

The second series of vents 15 is located on a second side of the fluid chamber 7, opposite the first side, between a first shoulder 13 and a second shoulder 14.

The rotary fluid connection 1 also includes pins 16, also called shutters, intended to take place in the vents 15.

More specifically, and preferably, the rotating fluidic connector 1 comprises half as many pins 16 as there are vents 15.

The pins 16 are thus housed in the vents 15 so that, for the same series, two consecutive vents are not both closed by a pin 16 or, on the contrary, free.

Each pin 16 comprises a first end 17 intended to cooperate with the friction means 6 as explained below, and a second opposite end 18 carrying means for fixing the pin 16 on the body 3.

The hollow shaft 4 has a tubular section closed at a first end by a head 19 and open at a second end opposite the first end.

More specifically, at the second end, the hollow shaft 4 has a flange 20 allowing the fixing of the hollow shaft 4 to an element of the movable assembly of the machine 2.

On its outer periphery, the hollow shaft 4 comprises two annular grooves 21 forming housings for the reception of an O-ring 5 as explained below.

The two annular grooves 21 are spaced from each other by a distance corresponding to a width of the fluid chamber 7 of the body 3.

At its first end, the hollow shaft 4 comprises at least one lumen 22 allowing, as explained below, a fluid communication between the interior of the hollow shaft 4 and the fluid chamber 7 of the body 3 .

More specifically, as illustrated in FIG. 1, the hollow shaft 4 includes several openings 22 distributed in a first annular row and a second annular row, the first annular row and the second annular row being staggered with each other.

Referring to Figure 2, the O-ring 5 has a friction surface 23 intended to cooperate with the friction means 6.

More particularly, the friction surface 23 is turned radially outward from the hollow shaft 4, that is to say towards the body 3.

According to an advantageous embodiment, the O-ring 5 has a first part 5a and a second part 5b.

The first part 5a is advantageously made of elastomer and the second part 5b, which carries the friction surface 23, is made of a harder material.

The use of an elastomer to produce the first part 5a, which is housed in an annular groove 21 of the hollow shaft 4, ensures good sealing between the O-ring 5 and the friction means 6 .

Indeed, by its natural elasticity, the first part 5a repels the second part 5b, and therefore the surface 23 of friction, against the means 6 of friction 6.

The friction means 6 are in the form of rings 24.

More specifically, the friction means 6 comprise two rings 24 each mounted in one of the first annular shoulders 13 of the body 3.

Each ring 24 is mounted in an annular shoulder 13 of the body 3 with radial clearance. Preferably, the radial clearance is between 0.05 mm and 0.11 m and is preferably 0.08 mm.

This radial clearance allows in particular to allow each ring 24 a swiveling movement relative to the body 3. This swiveling movement allows to compensate for any misalignment of the hollow shaft 4 relative to the body 3, and in particular by relative to the X axis.

The swiveling of a ring 24 is defined by two rotational movements of the ring 24 along two axes perpendicular to each other and perpendicular to the X axis to form with the latter a direct trihedron.

Each ring 24 carries a surface coating located on a radially internal face of the ring 24, that is to say a face opposite the hollow shaft 4. This surface coating is intended to cooperate with the friction surface 23 of the O-ring 5.

Preferably, the surface coating is made of chromium oxide and / or chromium carbide.

Furthermore, as illustrated in FIG. 3, each ring 24 has at least one notch 25 intended to receive the first end 17 of one of the pins 16.

More specifically, each ring 24 comprises several notches 25 distributed over its periphery.

When the rings 24 are mounted in the body 3, the first end 17 of each pin 16 is housed in a notch 25 in one of the rings 24.

This has the effect of keeping the rings 24 in position and in particular of preventing their rotation in the body 3, the rotational movement of the hollow shaft 4 combined with the friction of the O-rings on the rings 24 which can cause l ring rotation drive 24.

In addition, still with reference to FIG. 1, the rotating fluidic connector 1 comprises two bearings 26 interposed between the body 3 and the hollow shaft 4.

More specifically, the rotating fluidic connector 1 comprises two bearings 26 each positioned on either side of the fluid chamber 7, each bearing 26 taking place in one of the second annular shoulders 14.

Each bearing 26 advantageously takes the form of a ball bearing having:

- A first ring 27 secured to the body 3 (also called the outer ring);

- A second ring 28 secured to the hollow shaft 4 (also called an inner ring);

a series of balls 29 each interposed between the first ring 27 and the second ring 28.

As illustrated in FIG. 1, the first bearing 26 is partly mounted on the hollow shaft 4, at the level of the head 19, and partly on the body 3.

More specifically, the second ring 28 of the first bearing 26 is mounted in a first shoulder formed on the head 19 of the hollow shaft 4 and is held there by a circlip 30 fixed on the head 19. The first ring 27 is , meanwhile, mounted in a second annular shoulder 14 of the body 3.

Like the first bearing 26, the second bearing 26 is partly mounted on the hollow shaft 4, and partly on the body 3.

More specifically, the second ring 28 of the second bearing 26 is mounted in a second shoulder of the hollow shaft 4, and the first ring 27 is mounted in the other second annular shoulder 14 of the body 3.

By the orientation of the shoulders 13, 14 and by the joining of the second ring 28 of a bearing 26 on the hollow shaft 4, the hollow shaft 4 is held in position in the body 3.

In operation, the hollow shaft 4, which is mounted in the body 3 through the openings 8, is rotated by the movable assembly of the machine 2.

The hollow shaft 4 therefore rotates around the axis X, the body 3 being fixed since it is secured to the frame of the machine 2.

During the rotation of the hollow shaft 4 4, each O-ring 5, and more particularly its friction surface 23, cooperates, that is to say rub, on the chromium oxide coating and / or chromium carbide of the ring 24 opposite.

By the rotation of the hollow shaft 4 and the friction of the O-ring 5, the friction means 6 heat up rapidly. This is amplified by the presence of the pressurized fluid, that is to say air at a pressure of 40 bars.

To allow the cooling of the friction means 6, either of the air external to the rotating fluidic connector 1 circulates between the fins 11 of the cooling means 10, or a heat transfer fluid is injected into the pipes 12 of the fluid circuit of the body 3.

The air which circulates between the fins 11 allows the heat from the fins 11 to be dissipated by dissipation and therefore creates a heat exchange between the fins 11 and the air.

For the heat transfer fluid, it enters the body 3 at a temperature below the temperature of the body 3 and then, as the path in the pipes 12, is loaded with calories from the body 3.

The fluid is then removed from the body 3 to be cooled and then again injected into the body 3 via a closed loop.

The presence of the pins 16 in the vents 15 allows to confine, and in particular as is visible in Figure 1, to maintain the friction means 6 relative to the body 3 so that the cooling means 6 of friction is ensured by contact between the body 3 and the friction means 6.

For this purpose, at least the body 3 is made of a thermally conductive material such as an aluminum alloy.

The vents 15 which are not closed by a pin 16, allow that in the event of failure of the cooperation between one or each O-ring 5 and the friction means 6, the pressurized air leaking through the gap left between the O-rings 5 and the friction means 6, can escape from the body 3.

This in particular makes it possible to prevent the pressurized air from drying out the ball bearings forming the bearings 26, that is to say ejecting the grease out of the ball bearings, and therefore seizing the bearings.

To avoid premature wear of the pins 16 and / or rings 24, the pins 16 can in particular be moved from a closed vent 15 to a free vent 15, and thus offer a new support of the pins 16 on the pins 16 .

Claims (1)

Claims [Claim 1] Rotating fluidic connector (1) for the transmission of a fluid between a frame and an assembly movable relative to the frame in a machine (2) for manufacturing plastic containers, comprising: - a body (3) integral with the frame and defining a fluid chamber (7) intended to receive a fluid from at least one channel formed in the frame, the body (3) having at least one opening (8) opening into the chamber ( 7) fluidics; - A hollow shaft (4) secured to the movable assembly, and mounted in the body (3) through the opening (8), the hollow shaft (4) being movable in rotation relative to the body (3) and having at least one lumen (22) to allow fluid communication between the hollow shaft (4) and the fluid chamber (7); - at least one O-ring (5) having a friction surface (23) interposed between the opening (8) and the hollow shaft (4), and intended to prevent a flow of fluid between the hollow shaft (4) and the body (3) at the opening (8); - means (6) of friction intended to cooperate with the surface (23) of friction of the seal (5) O-ring (5) to help prevent a flow of fluid between the hollow shaft (4) and the body (3) at the opening (8), characterized in that the O-ring (s) (5) are carried by the hollow shaft (4) and the friction means (6) are carried by the body (3). [Claim 2] Rotary fluid connection (1) according to claim 1, characterized in that the friction means (6) are in the form of a ring (24) mounted in the body (3). [Claim 3] Rotary fluid connection (1) according to claim 2, characterized in that the ring (24) is mounted with radial clearance in a first shoulder (13) of the opening (8). [Claim 4] Rotary fluid connection (1) according to claim 2 or claim 3, characterized in that the ring (24) carries a surface coating intended to cooperate with the friction surface (23) of the O-ring (5). [Claim 5] Rotary fluid connection (1) according to the preceding claim, characterized in that the surface coating comprises at least one of the materials from: - chromium oxide; - chromium carbide. [Claim 6] Rotary fluid connection (1) according to any one of the preceding claims, characterized in that it comprises at least one bearing (26) interposed between the body (3) and the hollow shaft (4), outside the fluid chamber, to guide the rotation of the shaft relative to the body. [Claim 7] Rotating fluidic connection (1) according to the preceding claim, characterized in that the body (3) has at least one vent (15) opening into the interior of the body (3) between the fluid chamber (7) and the bearing (26 ). [Claim 8] Rotating fluid connection (1) according to the preceding claim, characterized in that the body (3) has several vents (15) distributed over the periphery of the body (3). [Claim 9] Rotating fluidic connector (1) according to the preceding claim, characterized in that it comprises at least one pin (16) inserted in one of the vents (15), the pin (16) having a first end (17) coming to the contact of the friction means (6) to block them in rotation relative to the body (3). [Claim 10] Rotating fluid connection (1) according to the preceding claim, characterized in that the friction means (6) comprise at least one notch (25) for the reception of the first end (17) of a pin (16). [Claim 11] Rotary fluid connection (1) according to any one of the preceding claims, characterized in that the body (3) comprises means (10) for cooling. [Claim 12] Rotating fluid connection (1) according to the preceding claim, characterized in that the cooling means (10) are in the form of fins (11) external to the body (3) to allow cooling by dissipation. [Claim 13] Rotary fluid connection (1) according to claim 11 or claim 12, characterized in that the cooling means (10) comprise an internal fluid circuit intended to allow the circulation of a heat transfer fluid in the body (3). [Claim 14] Machine (2) for manufacturing plastic containers by blow molding or stretch blow molding, comprising: - a frame; - an assembly movable relative to the frame; - a rotating fluid connection (1) for the transmission of a fluid between the frame and the mobile assembly according to any one of the preceding claims.