RU2779735C2 - Centrifugal press flywheel (options) - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: invention relates to the field of mechanical engineering, in particular to mechanical presses, the operation of which is based on the use of centrifugal forces to convert rotational motion into translational. The working body of the press is a steel belt flywheel, in which the central part of the winding is removed, and the axis of rotation is turned 90° relative to the rim and coincides with the plane of the winding of the tape. The flywheel ring (2) is installed in the frame (1), which has the shape of an oval, elongated vertically, which is fixed in the ring holders (3) mounted on the rotation shafts (4). The upper rotation shaft has the ability to move up and down, is brought out of the frame and is held in the upper position by means of a spring (5). In the rotation mode, under the action of centrifugal forces, the side parts of the flywheel diverge to the sides, its poles converge and through steel plates (6) press on the workpiece (7).

EFFECT: as a result, the possibility of obtaining large forces created by the press is provided, with a relatively small mass and size of the press.

10 cl, 18 dwg

Description

The invention relates to the field of mechanical engineering, in particular to mechanical presses using centrifugal forces in their work. In addition, it can be used as a mechanism for converting rotational motion into translational.

As an integral structure, among the machines and press equipment known in the art, this invention has no analogues.

But its separate and main part - the working body of the press, is outwardly similar and has a steel belt flywheel as a prototype, with only two differences from the classical design. The most important thing is the absence of an internal part with a hub, which did not allow the flywheel to change shape. And the second difference is the rotation of the axis of rotation relative to the turns of the tape, which led to a violation of the internal balance (balance of forces) in the flywheel rim and made it possible to convert the rotational motion into translational.

And according to the method of creating force, a centrifugal press, as its name implies, is similar to a centrifuge using the same centrifugal forces, only in it they act directly on the object being processed, and their level (with equal acceleration) completely depends on its mass, which has its limitations. In this invention, centrifugal forces arise in the side parts of the rotating flywheel, and from there are transferred to the workpiece itself. And since the mass of the flywheel can be very large, exceeding the mass of the workpiece by several orders of magnitude, then its efficiency will be as many times higher than in the case of a centrifuge.

The scheme of the centrifugal press in the idle state is shown in Fig. one

The device consists of a frame 1 inside which the working body of the press is located - the ring 2 of the belt flywheel, which has the shape of an oval elongated vertically. It is fixed on ring holders 3, which are mounted on rotation shafts 4, the upper of which, having the ability to move up and down, goes outside the frame and is held in the upper position by a spring 5. The lower rotation shaft 4 goes out through the frame frame and is connected to the drive shaft which is not shown in the diagram. Steel plates 6 are attached to the holders of the ring 3, on the lower of which the workpiece 7 is installed.

The scheme of the centrifugal press in operation is shown in Fig. 2

After the start of the flywheel rotation, centrifugal forces begin to act on the side parts of the ring 2, leading to its deformation and lowering of the upper part together with the ring holder 3 and the plate 6 onto the workpiece 7. After the flywheel reaches the calculated speed, the press force increases so much that it begins to exceed the yield strength of the material workpiece and it begins to deform. After the press has done useful work, the rotation of the flywheel is slowed down by applying passive or active (regenerative) braking. After it stops, under the action of the elastic forces of the ring 2 and the spring 5, the flywheel rim straightens, occupying the upper position. This completes the press cycle.

As can be seen from the above description, the working body of the press is a steel tape flywheel, but not with a solid winding, but hollow - with a removed core, the turns of which can freely slide relative to each other. Thanks to this design, the flywheel ring or rim can be deformed with sufficient amplitude, changing its shape from oval to round and vice versa.

It is known from the theory of machines that in a classical tape flywheel the axis of rotation is perpendicular to the plane of the tape winding, and the flywheel itself is an integral structure without the possibility of changing its shape. Therefore, the centrifugal forces arising in such a flywheel during rotation are directed radially from its center and completely balance each other without causing any internal deformations and movements, and the tape itself only works in tension (top view in Fig. 3).

But the above picture will completely change if instead of a solid flywheel we take a hollow flywheel, and rotate its axis of rotation by 90 °, placing it parallel to the plane of the tape winding. As a result, the vectors of centrifugal forces will make a turn in the same plane and become parallel to each other and perpendicular to the axis of rotation (shown by arrows in Fig. 4). In this case, the horizontal component of these forces will reach a maximum, and their vertical component (the projection of centrifugal forces on the axis of rotation), on the contrary, will become equal to zero.

Now the balance of forces in the flywheel ring will be disturbed and at its poles (at the points of intersection with the axis of rotation) forces P ₁ and P ₂ will appear directed inside the ring, under the influence of which it will begin to deform and put pressure on the workpiece, thereby doing useful work.

The main characteristic of the press is the force it develops, which is completely determined by the centrifugal forces F _c acting on the mass enclosed in the flywheel rim, which can be found by the formula:

where m is the mass of the flywheel in kg;

a - centrifugal acceleration in m / s ² ;

V is the linear speed of the flywheel rim in m/s;

R is the radius of rotation of the flywheel rim (average value) in meters.

From this formula it follows that the press force is proportional to the kinetic energy of the flywheel (mV ² ) and inversely proportional to its diameter.

Further, as an example for calculation, we take a ring wound from a steel tape with an outer diameter of 3 m, an average radius of rotation of 1.2 m, a rim width of 0.6 m and a mass of 20,000 kg, and we set the linear speed of movement to 500 m / s. Substituting these values into the formula, we get the result 4170000000 N, of which only a small part of it takes part in the creation of the useful force P ₁ (see Fig. 4). We conditionally accept that it accounts for a fourth of the total forces F _c . Then, dividing the result of 4170 MN by 4 and converting newtons to tons, we get that at a circular rotation speed of 70 rpm, a flywheel ring with a mass of 20 tons creates a useful force P ₁ equal to 100,000 tons-force.

It should be understood that the above method of calculation is very approximate and suitable only for a rough estimate of the force of a centrifugal press.

Nevertheless, it clearly shows what colossal power centrifugal forces can create in a rotating flywheel and testifies to the high specific characteristics of this machine, because the press at maximum speed is able to develop a force that exceeds its own weight by 5000 times!

Of course, it did not include the mass of the frame itself and other equipment, but still this is a very high figure and for comparison, let's say that the most powerful hydraulic press of NKMZ with a force of 70,000 tons has only 4 units, which is three orders of magnitude less, than a centrifugal press.

If we now proportionately increase the size of the flywheel by more than three times, bringing the outer diameter to 10 m and maintaining the same linear speed of 500 m / s, then its mass will increase to 700 tons, and the press force will increase to 1,000,000 tons-force.

If we continue the same operation with an increase in size, we will get a press with a flywheel diameter of 30 m, and its mass will already be 20,000 tons, and the force will increase to 10,000,000 tons-force.

From the obtained results it can be seen that with an increase in the linear dimensions of the flywheel, the mass of its ring grows to a cubic degree, the press force is only squared, and the specific power, on the contrary, decreases in a linear relationship.

Summarizing the above, we note that the main advantage of this invention is the super-high force generated by a centrifugal press with a relatively small size and weight of the installation, which allows you to build very powerful presses at lower financial costs compared to their hydraulic counterparts.

In addition to the above advantages, this design has serious disadvantages.

1. Since the workpiece is located inside the flywheel and rotates with it, centrifugal forces also act on it, which can lead to its deformation and even destruction.

2. A rotating flywheel at operating speed has a very high kinetic energy, part of which will inevitably be lost during its braking, which indicates its low energy efficiency.

3. It takes a lot of time to accelerate the flywheel and then decelerate it, which stretches the duty cycle and reduces its performance. From this, in turn, follows the fourth disadvantage of the press.

4. This is the impossibility to quickly regulate its force and accurately dose the movement of the "traverse" of the press, which for some technological operations on the workpiece is an important factor in obtaining a high quality product. It should be clarified that this movement is generally not amenable to direct regulation and somehow influence this process is possible only indirectly - through a change in effort, and hence the speed of the flywheel.

5. The fast-rotating rim of the flywheel, like a fan, creates a powerful vortex around itself, which makes it impossible for maintenance personnel to be near it, and also sharply increases energy losses due to air friction, further reducing its efficiency.

6. Minor shortcomings of the press include the vibration of its flywheel and the difficulty of monitoring a rapidly rotating workpiece.

All the disadvantages listed above have one or another way to eliminate them completely or partially, which will be discussed in the rest of the article.

Additional types of centrifugal press designs.

In addition to the single-ring scheme of the flywheel, it can be made in the form of two interconnected tape rings having a common axis of rotation and located at some angle to each other, where the angle equal to 90° is chosen as the main option, as shown in Fig. 5 (top view). Moreover, the tapes of these rings, intersecting at the poles of the flywheel, mutually alternate, as shown in Fig. 6, which shows a longitudinal section through the top of one of the rings.

The advantage of this design is doubling the mass of the flywheel, and hence the effort of the press, with the same dimensions. And the downside is the difficulty in manufacturing (winding) a double flywheel ring. In addition, the thickness of the rim in the region of the poles doubles, which somewhat reduces the maximum amplitude of the stroke of the "traverse" of the press.

When describing the device of a centrifugal press, one of its main drawbacks was given - this is the rotation of the workpiece along with the flywheel. It is possible to get rid of it, and hence of harmful centrifugal forces, if the plates with which the workpiece is in contact are made immovable by placing sliding bearings made in the form of two disks between them and the ring (rim) of the flywheel, and in relation to its lower part, one of them (outer and movable disk) must be connected with a sleeve pressed into the ring and then with the flywheel rotation shaft, making it hollow, through which the fixed axle will pass and connected at the top with the inner (fixed) bearing disk, and below, at the exit from it, it will be attached with a bracket to the frame. To eliminate friction between the discs, it is necessary to apply liquid or gaseous (preferably helium) lubricant under high pressure into the gap between them.

At the same time, the upper part of the press has the same design as its lower part, but with its own differences. The central axis that passes through the hollow shaft of the flywheel must be able to move (lower and rise) simultaneously with it, but without rotating. Therefore, it should be attached to the frame not rigidly with a bracket, but through a sliding assembly, the design of which is very similar to the design of the sliding shaft of the centrifugal press shown in Fig. 14 (description see page 11).

A circuit that implements this option is shown in Fig. 7

The drawing shows the lower part of the press and sections of parts: the lower (outer and movable) disk 8, which is attached to the hollow sleeve 10, which, together with the hollow shaft of rotation 4 of the flywheel, forms a single whole, as well as sections of the sections of the ring 2 and frame 1 adjacent to them.

Shown in one piece: the central (fixed) axis 11, the lower end of which is attached with a bracket 12 to the frame 1, and the upper end is connected to the upper (inner and fixed) disk 9, on which a steel plate 6 is installed, which transmits pressure to the workpiece. In the center of the fixed axis. And there is a through hole (indicated by dashed lines), through which helium moves to the upper disk 9 and passes through small holes in it into the gap between the disks and exits (shown by arrows in the diagram). In turn, the hollow shaft 4 of the flywheel, going outside the frame 1, through a gear (or other) transmission is connected to the drive shaft, which are not shown in the diagram.

Using the example of a press with a force of 100,000 ton-force, we find the helium pressure in the gap between the plates. With their area equal to 1 m ² , it will be 10,000 atm., Which is very, very much. Therefore, in practice, the press force will have to be reduced by 2–3 times, thereby reducing the gas pressure.

It is also possible to increase the contact area of the plates by proportionally increasing all the dimensions of the press and bringing the diameter of the flywheel up to 5 - 6 meters, which at the same time will increase its cost.

But there is another way to reduce the gas pressure.

Since the plates that press on the workpiece remain motionless with it, there is no need to place it inside the flywheel. The workpiece can be taken out by placing it between two flywheels, and the compression force can be transferred to it using power beams.

A circuit that implements such a variant of the press is shown in Fig. eight

In this design, there is no frame, and its function is performed by two horizontal beams 13, which transmit the force from two flywheels 2 located along its edges, through steel plates 6 to the workpiece 7. The upper beam-traverse 13 is supported by two hydraulic cylinders 14, which raise after the end of the working cycle.

In this case, the plain bearing (items 8, 9 in Fig. 7) can, as in the previous version, be located inside the flywheel, or it can be taken out, as shown in Fig. 8 (item 15) and placed in recesses along the edges of the beams (depicted by dashed lines). In this case, instead of a hollow shaft and a central axis (on each side of the flywheel), it will have only one solid shaft, but with an increased diameter.

Since this scheme already consists of two flywheels, the gas pressure in the plain bearing between the disk-plates (with the same cross section) will be half as much. It can be further reduced if the number of power blocks (flywheels) is increased to 3, 4, 5, 6, and so on, by placing them symmetrically in a circle relative to the center with the workpiece.

The advantage of this design of the centrifugal press is the immobility of the workpiece with plates and, as a result, the absence of unpleasant consequences (deformations) from its rotation. And compared to the variant in Fig. 7 its size is no longer limited by the size of the flywheel and can be as large as giant hydraulic presses.

But this option also has a significant minus - these are high tensile forces acting on the flywheel rotation shafts. Therefore, they must be of large cross section and made of high-strength steel.

At the beginning of this article, it was described how to obtain an imbalance of forces in a rotating flywheel, which is necessary for the operation of the press, by turning the axis of its rotation by 90 °, due to which the vectors of centrifugal forces unfold and useful forces P ₁ and P ₂ appear, directed inside the flywheel ( see Fig. 4).

In addition to this method, which can be called vector, there is another method to obtain the same result: this is when the axis of rotation of the flywheel does not change and it maintains a perpendicular position to the plane of the tape winding.

In this case, the necessary imbalance of forces can be obtained by unevenly distributing the mass in the ring (or rim) of the belt flywheel, with the central part of the winding removed, using two methods:

The first is by adding extra (ballast) mass inside the flywheel rim on its opposite sides. Due to low efficiency and increased complexity, this method has no prospects and is not considered in this article.

The second is by changing the section (width) of the rim itself, simultaneously increasing and decreasing it in mutually opposite directions, as shown in Fig. 9 (side view from the side of the flywheel pole).

In FIG. 10 shows the same flywheel (top view), the center of rotation of which coincides with the intersection point of the coordinate axes x and y, and the mass of its rim near the x axis is greater, and near the y axis is less than the average value. Because of this, an inequality arises between the centrifugal forces F _c.y (the sum of the projections of the vectors F _c on the y axis) and F _c.x (the sum of the projections of the vectors F _c on the x axis). As a result of the resulting imbalance of forces, at the poles of the flywheel (at the points of intersection with the y-axis), pressure forces P ₁ and P ₂ appear directed inside the ring, which can be used to process (deform) the workpiece.

The values of these forces (in the case when the flywheel rim has a circular geometry) can be calculated by the formula: P ₁ + P ₂ \u003d F _c.x -F _c.y

A circuit that implements such a variant of the press is shown in Fig. 11 (side view) and in FIG. 12 (top view).

Instead of a frame, this press uses a round platform 16 with a thickening in the center, mounted on a rotation shaft, which is fixed at the base of the press 17 and to which a power drive is connected (not shown in the diagram). The flywheel ring 2 is mounted on two ring holders 3, which freely and synchronously move from the center of the platform to its periphery and back. In the rotation mode, the force from the flywheel rim is transmitted from its poles through the steel plates 6 to the workpiece 7, which slide freely along the steel beam 18.

A centrifugal press built according to this scheme has its advantages: simplicity of design and lack of a frame, small dimensions and low air resistance.

However, the design features of this scheme do not allow creating a sufficiently large imbalance of masses (and hence forces) in the flywheel rim. Since, with the optimal ratio of the width of its rim at the poles and the periphery of 1 to 2, the heavy part of the flywheel accounts for 58% of the mass, and the light part accounts for 42%, which is a difference of only 16% (of the total mass of the flywheel), which creates the necessary (useful) imbalance of forces in the centrifugal press. This is in theory, but in practice this value will be even less due to the negative effect of steel plates transmitting pressure on the workpiece, and given the lower maximum flywheel rotation speed (due to the small width of its rim near the poles), the real indicator of its effectiveness will be even less and will be about 10%.

Therefore, in terms of specific power characteristics, such a press will be inferior to a press with a vertically located flywheel (with a vector imbalance of forces), in which this indicator in theory and in practice reaches 50%, due to which, with an equal mass, it will have a fivefold superiority in effort.

This design also has other, smaller flaws, which, together with the main drawback, make its use economically unprofitable and technically unfeasible in practice.

Additional types of designs of a centrifugal press with a fixed workpiece and helium lubrication.

Above in the description (on pages 5, 6) a variant of the press with a fixed workpiece was given, which has the disadvantage of the impossibility of direct connection of the electric motor to the flywheel shaft. You can get rid of the central axis that interferes with this by switching from a passive plain bearing to its active version, which has a built-in motor winding in the lower (outer and movable) disk, and built-in permanent magnets in the upper (inner and stationary) disk.

Thanks to this design, when an alternating voltage is applied to the winding, a rotating magnetic field arises in the gap between the disks, which drags the upper disk with permanent magnets along with it. Thus, when the flywheel shaft rotates in one direction, the upper disk with the workpiece installed on it will begin to rotate in the opposite direction, remaining stationary relative to the frame, or moving after the flywheel at low speed.

Therefore, the need for a central axis, which kept the top plate from rotating, connected to the frame by means of a bracket, is completely eliminated. And now the flywheel shaft can be connected directly (and not through a gear train) to the drive shaft. In this case, in both shafts (flywheel and electric motor) there must be a central through hole through which helium gas will flow upwards to the plain bearing. Also, a cable will pass through it, feeding the motor windings in the lower (moving) bearing disk. And since the electric cable will rotate with the flywheel, before entering it into the hole of the motor shaft, there must be a device (electric coupling) that separates the fixed part of the cable at the input and its movable part at the output through sliding contacts. In this case, the body of the electrofusion will be under a very high pressure of helium, and in order to withstand it, it must have thick walls and be made of high-strength material.

A circuit that implements such a variant of the press is shown in Fig. 13

The drawing shows the lower part of the press, consisting of a flywheel ring 2, in the tape of which a sleeve is pressed, which is connected at the top to the outer (movable) disk 8 of the plain bearing, which incorporates electromagnetic coils 19 of the auxiliary electric motor, and from below it is connected to the rotation shaft 4 , which, leaving the frame 1, is connected to the shaft of the power motor 20, at the lower end of which there is an electric coupling 21, which has two inputs: for helium and a power cable. In turn, on the inner (fixed) disk 9 of the plain bearing, containing permanent magnets 22, there is a steel plate 6 that transmits pressure to the workpiece. Along the central axis of the electric motor and the flywheel shaft, as well as the bushing and the outer disk, there are through holes through which helium rises to the inner disk 9 and passes through small holes in it into the gap between the disks, and then goes outside the bearing (shown by arrows in the diagram).

In this case, the upper part of the press can be made according to the old scheme (a hollow shaft with a central axis) or have the same design as its lower part (with electromagnets), or a completely new one, which will be described below.

Since the upper part of the press is passive (without a power drive), this entire assembly can be made in a completely different way, namely: to make the flywheel shaft independent (semi-free), separating it from the flywheel itself. Thanks to this, it can remain stationary, but still perform its function: keep the flywheel rim from moving (center it) and raise it after the end of the work cycle.

Now the stationary shaft will pass through a hollow sleeve pressed into the flywheel rim, and then through the hole in the upper (outer) disk of the plain bearing, it will be connected at the output to the lower (inner) disk of the same bearing. As before, helium lubricant must be supplied to the bearing disks through the central hole of the fixed shaft.

Since a torque will act on the shaft with a fixed disk from the side of the rotating disk of the bearing, it will need to be stopped.

In the first design variant, as shown in Fig. 7 (in relation to its upper part), this was achieved using a central axis, which was attached to the frame through a sliding assembly and kept the bearing disk from turning.

In the second version of the design (Fig. 13), the torque was stopped by the motor winding, which creates an electromagnetic torque with the opposite sign.

The third design option is identical to the first, only the central axis here is replaced by a semi-free (semi-movable) flywheel shaft, which is structurally designed as follows: its outer end with a semicircular head has two protrusions (lugs) on the sides that enter the grooves of two rails installed vertically at the top of the frame on the sides from the top shaft with a spring. Thanks to this, the flywheel shaft can move up and down (simultaneously with the rim), but without turning.

As can be seen from the description, the third design option for the top of the press is the best, as it contains fewer parts and does not require a supply voltage. Is it possible to simplify the lower part of the press, excluding from it the electric motor in the plain bearing along with the cable and the coupling?

There is one easy way to do this. To do this, it is necessary to mechanically connect (connect) both internal (fixed) disks of plain bearings into a single whole by installing a jumper between them. The connection must be soft (movable) in the longitudinal direction (along the axis of rotation) and rigid in the transverse direction. Structurally, it can be made in the form of two flexible half-rings, with their ends connecting both disks into a single whole, as shown in Fig. 14 (para. 23). Like the flywheel rim, this ring has an oval shape, elongated vertically. It can be made from metal band, but only thicker than the flywheel band, and from cheaper steel. You can go even further by increasing the rigidity of the half rings so that they can support the weight of the upper part of the flywheel and, after the end of the working cycle, lift it up without the help of a spring, which will eliminate it from the design of the press.

Thus, a centrifugal press flywheel with a stationary workpiece will consist of two belt rings: a large flywheel ring, the rotation of which creates the necessary pressure, and a small jumper ring, with a diameter and thickness smaller than the main one, structurally connected to the fixed disks of plain bearings and capable of replacing return spring.

A circuit that implements such a variant of the press is shown in Fig. fourteen

On the lower rotation shaft 4, the ring 2 of the flywheel and the lower (outer) disc 8 of the plain bearing are rigidly fixed (pressed in), on the short axis of which the upper (inner) disc 9 of the same bearing is mounted. Both inner disks 9 are connected on both sides by a flexible jumper 23, while the upper of the disks is attached to the end of the upper (semi-movable) shaft on the axis of which freely rotate, fastened together, the flywheel ring 2 and the upper (outer) disk 8 of the plain bearing. Having passed the hollow flywheel sleeve, this shaft goes outside the frame, where it is held in the upper position by a spring 5, on the sides of which there are two guide rails 24, which have internal grooves, along which, when lowering and raising the flywheel, two protrusions (ears) slide, located on semicircular end of the upper shaft. Both flywheel shafts, as well as the electric motor shaft (which is not shown in the diagram), have through central holes through which high-pressure helium gas enters the plain bearing discs, and, having passed through which, it freely exits.

In addition to an independent method of supplying gas to the disks of plain bearings, a dependent variant is also possible, when helium is supplied to one of the bearings not directly through a hole in the shaft, but indirectly - from the second, opposite plain bearing, by making a tap from its inner (fixed) disk, and then it is directed to the inner (fixed) disk of the first bearing through a flexible high-pressure pipeline. But this method is applicable only for variants with rigidly fixed (relative to the frame) inner disks of plain bearings, which are shown in Fig. 7 and FIG. 14. And the option with a "soft" mount (see Fig. 13) is not suitable for this, because. involves slippage between the inner discs, which will inevitably lead to pipeline damage.

This way of supplying helium is especially suitable for the variant with an internal bridge (see Fig. 14), because the pipeline (or pipelines) can be directly fixed on the sides of the jumper ring, which will increase their safety. At the same time, it is better to make the upper part of the flywheel independent in terms of lubrication (through the fixed shaft of which it is easier to bring gas to the upper bearing and further down), and to make the lower part of the flywheel dependent, because. in this case, the need for the central hole of the electric motor is eliminated.

To put into practice such a (dependent) method of supplying helium, a flexible pipeline is needed that can withstand a pressure of several thousand atmospheres, and its creation is a difficult technical task.

To facilitate its solution, the gas pressure in the pipeline after passing the upper bearing with the help of a reducer is reduced to several hundred atmospheres and then, after it is entered into the inner disk of the lower bearing, it is increased by an order of magnitude using a compressor installed in the same disk (and due to lack of space, then in the steel plate adjacent to it). At the same time, it will take energy for its work directly from the rotating shaft of the flywheel, with which it (its rotor) will be mechanically connected.

All of the above methods of supplying helium were supposed to release the gas after its use into the atmosphere of the room, and then extract it from the air again, which would significantly increase the cost of servicing the centrifugal press, since this process is complex and expensive.

To eliminate this shortcoming, it is necessary to switch to a closed, and therefore more economical helium use cycle, and for this to equip the plain bearings with hermetic screens (in the form of a ring enclosing a fixed disk), from under which the gas is pumped out with a vacuum pump and sent for reuse. But this implies the presence of low-pressure pipelines, through which helium will flow in the opposite direction, and placing them in the flywheel shafts simultaneously with high-pressure pipes (especially on the motor side) is very problematic. Of course, the role of the return pipeline can be successfully performed by the gap between the fixed shaft and the hollow flywheel sleeve in relation to its upper part, but in the case of the lower shaft, everything is much more complicated, because. it is movable and mechanically connected to the motor shaft and therefore it will be a very difficult task to separate the two gases (high and low pressure). We will not go into details of the difficulties that design engineers of this type of press will have to face, but rather we will immediately proceed to the description of its improved version.

It involves the rejection of the return pipeline in the lower (rotating) flywheel shaft and the transition to a through helium supply scheme. Its idea is that from one (lower) side helium enters the flywheel under high pressure, and after passing through both plain bearings in series, it comes out from the other (upper) side under low pressure.

The scheme of such a variant of the press, with a through supply of helium in a closed loop, is shown in figures 15, 16, 17, 18.

In FIG. 15 shows the lower part of the flywheel, through the rotation shaft of which helium under high pressure, having passed the outer (movable) disk 8, enters the gap between the disks of the lower plain bearing, from where it comes out and already at low pressure and at high speed, helium goes around the inner surface screen 25 (it is shown in section) and enters the side holes 26 of the inner (fixed) disk 9, which have a rectangular profile, where it moves along the system of internal channels (separated by thick partitions) towards the jumpers 23. In turn, part of the helium in the gap between the disks branches off through 4 holes (passing through thick partitions) and goes to 4 high-pressure pipelines 27, running along flexible bridges 23 (in Fig. 15 they completely merge with each other, since they have the same thickness as the bridge), and then along with it, it moves up to the inner (stationary) disk of the upper plain bearing.

In FIG. 16 shows the same (lower) plain bearing (top view) with part of both webs and flexible pipes, but without the flywheel rim.

The dashed arrows indicate the direction of movement of low-pressure helium (with the exception of the arrows entering the high-pressure pipelines 27), which, having passed the screen 25, and turning around, enters the side holes 26 of the fixed disk 9 and, moving along the internal channels between the thick partitions, it turns to the angle is from 90° to 180° and goes to the jumpers 23, inside which and in their center there is a cavity 28, which performs the function of a low-pressure pipeline, and through it helium moves further to the inner (fixed) disk of the upper plain bearing.

In FIG. 17 shows the upper part of the flywheel with a hollow fixed shaft, to the end of which is attached the inner (fixed) disc 9 of the plain bearing, on the sides of which there are flexible bridges 23 connecting both inner discs 9 into a single whole and having in the center a cavity 28 through which helium with high speed and under low pressure enters the same (fixed) disk 9 and further, through a system of internal channels (separated by thick partitions), it moves to the center of the disk and, turning by 90 °, helium exits the press through the hollow shaft of the flywheel. In turn, along two jumpers 23 (on their sides) there are 4 flexible pipelines 27 (in Fig. 17 they completely merge with each other, since they have the same diameter as the jumper) through which helium enters the internal (fixed) under high pressure disk 9 of the upper sliding bearing and, having passed 4 holes in thick partitions, enters the gap between the disks and goes outside, where it already goes around the inner surface of the screen 25 at high speed and under low pressure (it is shown in section) and enters the side holes 26 of the same disc 9, which have a rectangular profile, where helium moves through the internal channels to the center of the disc and, turning by 90°, through the hollow shaft of the flywheel, it exits the press.

In FIG. 18 shows the same (upper) plain bearing (bottom view) with part of both webs and flexible pipes, but without the flywheel rim.

The dashed arrows indicate the direction of movement of low-pressure helium (with the exception of the arrows coming from high-pressure pipelines 27), which, having passed the screen 25 and turning around, enters the side holes 26 of the fixed disk 9 and goes through the internal channels to the center of the disk, where it turns 90 ° helium, through the hollow shaft of the flywheel, exits the press.

The problem of helium reuse can be solved without resorting to a complex scheme for capturing it and withdrawing it outside the press. There is another option, according to which it goes out of the plain bearings into the room, the gas composition of which coincides with the gas composition of the lubricant supplied to the bearings. In this case, pure helium is not the best application, because press service personnel will be forced to use breathing apparatus. Therefore, helium must be diluted with oxygen, making it breathable, and in this composition used to lubricate plain bearings.

But this option also has two significant disadvantages: for the attendants, this is a significant change (increase in tone) of the voice during a conversation, and for the press itself, due to an increase in the viscosity of the gas mixture, this is an increase in friction losses, which will increase the heating of both the gas itself and bearings, as well as increase the torque acting from the rotating disks on the fixed bearing disks.

Despite these shortcomings, such an option for using helium still has the right to exist, due to its simplicity and economy.

One of the serious shortcomings of the centrifugal press is its rotation at supersonic speed, as a result of which friction losses against air are very significant and therefore require special measures to reduce them.

One way to do this is to isolate part of the air that rotates with the flywheel from the rest of the air in the room by placing a screen of elastic material between them.

It can be movable and mounted on the outside of the flywheel, rotating with it, and then large centrifugal forces will act on it, which implies the use of high-strength material in the screen design, which cannot be transparent in its properties, which makes it difficult to observe the workpiece. However, this option is the best because of the minimum friction losses.

In the case of a fixed screen, due to the absence of centrifugal forces, the requirements for its strength are sharply reduced, and it can be made of a transparent and elastic material. Such a screen may have a round or oval shape of rotation, which should coincide with the outer shape of the flywheel and be installed with a small gap from its rim. And it should be attached in the area of \u200b\u200bthe lower and upper poles of the flywheel; in the latter case - directly to its fixed shaft, and if the design provides for its rotation - then through the sliding ring. Despite the obvious advantages of this design, the presence of a gap between the screen and the flywheel leads to air circulation inside them, which reduces the efficiency of this option compared to a rotating, tight-fitting screen.

In both cases, the elastic screen must have sliding flaps that provide access for operating personnel to the center of the flywheel with the workpiece. And if in the second version the air inside the flywheel is replaced by light helium, then this will allow, by reducing the viscosity of the gas, to significantly reduce friction losses. However, it must be borne in mind that when opening and closing the screen flaps, helium from it will get out, and air will enter inside, which will reduce the effect of its use.

In addition to a flexible screen that changes its shape simultaneously with the flywheel rim, it is possible to design a completely fixed screen made of a hard and transparent material, which is attached to the inner contour of the frame and is able to move apart, providing access to the inside of the press. However, in this case, the presence of a large gap between the screen and the outer part of the flywheel (tens of centimeters) negates the effect of its use, and only the presence of helium inside it could improve its efficiency.

And in relation to a press with an external arrangement of the workpiece (see Fig. 8), a rigid screen can be made of two fixed, but at the same time sealed cylinders sliding relative to each other, which not only isolates the flywheel from the external environment, but will create a strong vacuum inside them , up to a vacuum, which will completely solve the "air" problem.

One of the technical problems in the design of the press is to improve its energy performance associated with energy savings during the braking of the flywheel in the recuperation mode. Since energy losses are determined solely by the characteristics of the electric motor (its efficiency in generator and engine mode), and if we take the most common indicator of 90 - 95% and multiply them, then the total efficiency will be 81 - 90%. And this means that 10 - 20% of electricity will inevitably be lost during recuperation.

And if the electrical circuit of the recuperation does not allow achieving high savings, then maybe the mechanical circuit is capable of doing this? Yes, such a scheme and such a method of energy transfer exist, and it consists in refusing not only intermediate conversion (into electromagnetic energy), but also the use of a mechanical transmission, and these are all kinds of gearboxes and variators with low efficiency. You can do without all this if you choose a classic-type flywheel as an energy receiver (let's call it a secondary or simply second flywheel), which has the same moment of inertia as the main flywheel and has a bay with a tape on the shaft. And you can transfer energy to it from the press flywheel by rewinding the tape from the reel of the second flywheel to the same reel, but empty, located on the shaft of the first flywheel. During such rewinding, the press handwheel will begin to slow down, and the secondary flywheel, on the contrary, will accelerate, and when the tape is completely rewound, the speed of the second flywheel will reach its maximum value and become equal (or almost equal) to the speed of the press handwheel, which it had before the start of rewinding. At the same time, its revolutions will drop to a minimum value and amount to only a few revolutions per second. After the end of rewinding, the empty reel (using a clutch) is disconnected from the second flywheel (which continues to rotate) and both reels (full and empty) are braked together with the press handwheel. The reverse transfer of energy from the second handwheel to the first is carried out in the same way, only in this case the direction of rotation of the press handwheel is reversed. In addition to the above details, this system must have clutch flywheels on the shafts, a tape rewinding mechanism and its braking (and possibly tension), which makes it look like a VLM of a reel-to-reel tape recorder.

The efficiency of this recovery method can be judged by the residual rotational energy of the press flywheel, which, if its speed drops by a factor of 10, will be only 1% of the initial one, and the energy of the rewound tape will be the same, provided that its mass is equal to the press flywheel. The exact value of all losses depends on the material and weight of the tape, and may fluctuate in one direction or another.

With the reverse process of energy transfer from the second flywheel to the first, the losses will be approximately the same and in total will be about 5% of the initial value, which is 2 to 4 times less compared to braking by an electric motor in the recuperation mode. On the face of the energy and hence the economic benefit, which is achieved by complicating and increasing the cost of the entire mechanical system.

I must also say that the above method of energy transfer (using a tape drive) is not a new invention of the author, since it is already used in technology and is described in various patents, for example, ed. St. 335476 for 1970 "Device for acceleration of flywheel masses".

A logical and further development of this idea is to replace the second flywheel of a conventional design with the same centrifugal press flywheel as the first one. At the same time, their total cost will increase slightly, but energy losses will be halved and the performance of the system of two flywheels will increase by 2 times.

In addition to the direct purpose of the press flywheel - working with a workpiece, it can also be used for another purpose, for example, as a linear drive for a hydraulic cylinder for a powerful water jet gun.

To do this, instead of steel plates, a hydraulic cylinder is placed inside the flywheel, which, with its base, is attached to the ring holder on the side of the passive (not having an electric drive) pole of the flywheel, and rests against the ring holder on its opposite (active) side of the pole with its rod. In the center of the base of the cylinder, as well as in the tape and flywheel shaft, through holes are made to let water out. The same holes are made in the rod itself and in the flywheel tape, as well as in the flywheel and electric motor shafts, through which water will flow and fill the cylinder before starting work. At the same time, at the end of the rod (near the piston), there must be a valve in the hole that does not release water back from the cylinder. And also on the outlet (water jet nozzle) you need to install a damper with a centrifugal drive, which prevents water from flowing out when the flywheel is stationary.

The operation of a hydrodynamic gun is possible in two modes: main and auxiliary.

In the first case, the working stroke of the press, i.e. the movement of its "traverse" begins after the cylinder is filled with water and the flywheel is set at the calculated speed. And for this, its design must have a controlled locking mechanism that prevents this movement in the acceleration mode. It can be made in the form of two props installed parallel to the rod in the gap between the ring holder and the cylinder, and capable of moving apart under the action of an impulse from an electromagnet. But you can do it even easier and install a powerful shut-off valve on the outlet, instead of a simple damper, and open it when the flywheel reaches the design speed. The disadvantage of this method is the intermittent operation of the press, which requires each time at the end of the working cycle to stop the flywheel and fill the cylinder with water.

The auxiliary operating mode of the press differs from the main one in that the cylinder is filled with water immediately after it is emptied, with the flywheel rotating and simultaneously with its acceleration, which requires a high-pressure and high-power pump. With its help, under high pressure, water is injected into the cylinder, which presses on the piston with great force, causing the flywheel to spin up to high speeds, and its poles to diverge and store energy like a spring. At the same time, a shut-off valve capable of withstanding ultra-high pressure must necessarily be on the nozzle of the water jet.

As can be seen from the description, in this mode, there is no need to stop the flywheel every time, and then accelerate it again, which increases the productivity of the entire process, but still requires a break in its work. And also the presence in this circuit of a powerful pump with low efficiency, significantly increases the energy losses of the entire installation, and also complicates and increases the cost of it. In addition, both options have the disadvantage of a significant pressure drop in the cylinder, caused by a decrease in the press force in the lower position of the flywheel "traverse", which negatively affects the rate of water outflow.

In addition to the slow or smooth operation of the press, the centrifugal press handwheel can also be used in shock mode. To do this, it will be necessary to slightly modify its design by installing two supports between the steel plates, which prevent the movement of the "traverse" of the press during the acceleration of the flywheel, and having a remote drive.

On the example of a 100,000 ton press, let's see what impact force it can develop at maximum speed and a linear rotation speed of 500 m/s. And since the impact force or power is proportional to the kinetic energy released per unit time, you must first find the speed of its "traverse" (together with the parts of the flywheel adjacent to it), as well as its mass. And the calculation of its speed is complicated by the fact that for different parts of the flywheel it is different both in absolute value and in direction, and gradually decreases starting from top to bottom. And when the upper pole of the flywheel moves at maximum speed, then its parts near the "equator" move twice as slowly, and the lower pole generally remains motionless. Calculations will be greatly simplified if we conditionally assume that only half of the mass of the flywheel (10 tons) is involved in the movement, and that all of it moves at the same speed, equal to the speed of its upper part, and before hitting the workpiece, it travels a distance of 1 m.

Now, if the flywheel is untwisted to maximum speed and the supports are knocked out from under the plates, then its upper part with a mass of 10 tons, under the action ^of a force of 1000000000 N, will begin to move with an acceleration of 100000 m/s s, hitting the workpiece with incredible force.

This would be so if the centrifugal forces accelerating the flywheel remained constant. But since they sharply decrease with distance, the final speed of the "traverse" will be much less, about 350 m/s, which is still very high for a small workpiece, unable to withstand such a powerful blow, so as not to shatter. Indeed, after all, the energy of its impact will be about 600 MJ, which, in terms of TNT equivalent, will be 140 kg. It's the same as if a FAB-250 bomb weighing a quarter of a ton were blown up inside the flywheel. It is clear that such a huge energy released upon impact is very dangerous both for the flywheel itself and for the bed, and will inevitably lead to their damage. And the blow of such power for processing the workpiece in practice will not be in demand. Therefore, to operate the press in shock mode, the linear speed of its flywheel is limited to 50 - 100 m / s, which is quite enough for most cases.

And here the question arises by itself, is it possible to use such a powerful energy of the press, or rather its flywheel, to accelerate and disperse artillery shells, especially large calibers? Yes, this is possible, only the design of the press will have to be radically reworked, some elements removed and others added, turning it into a real centrifugal gun. But this is a topic for a separate application for an invention.

Claims (9)

1. A centrifugal press flywheel containing a vertically mounted frame, in which a flywheel is located in the form of a ring of steel tape wound with the possibility of free sliding of turns relative to each other, and steel plates, the lower of which is made with the possibility of installing a workpiece on it, while the axis of rotation of the flywheel is turned by 90° relative to the ring and is parallel to the plane of the tape winding, the ring has the shape of an oval, elongated vertically, and is mounted on the rotation shafts, the lower of which goes out of the frame and is connected to the electric drive, and the upper one is made with the possibility of moving up and down with the provision after the start of rotation of the flywheel for lowering the upper part of the ring with a steel plate onto the workpiece on the lower steel plate, is brought out of the bed and held in the upper position by means of an elastic element. 2. Centrifugal press flywheel according to claim 1, characterized in that in addition to the flywheel ring at an angle of 30 to 90 °, a second ring of steel tape is installed, which has a common axis of rotation with it, while the flywheel ring tapes, intersecting in the area poles, mutually alternate, forming a single structure. 3. Centrifugal press flywheel according to claim 1, characterized in that it is equipped with sliding bearings installed between steel plates and the flywheel ring, each of which is made in the form of an external movable metal disk attached to a sleeve, which is integral with the rotation shaft, made hollow, and an internal fixed metal disk mounted on a central axis passing through a hollow shaft of rotation, coming out of the frame and made with a through hole located along it in the center for supplying liquid or gaseous helium lubricant under high pressure into the gap between the metal disks, moreover, the central axis of the lower plain bearing is connected to the frame by means of a bracket and is fixed, and the central axis of the upper plain bearing is connected to the frame by means of a sliding assembly with the possibility of its movement up and down without rotation. 4. Centrifugal press flywheel according to claim 1, characterized in that it is equipped with upper and lower plain bearings, each of which is made in the form of an external movable disk and an internal fixed disk, while the flywheel ring and the outer movable sliding disk, on the axis of which the inner fixed disk of the specified sliding bearing is mounted, on the upper shaft for rotation, a flywheel ring is mounted, fastened to the outer movable disk of the upper sliding bearing, and the inner fixed disks of the sliding bearings are connected by a flexible bridge, which consists of steel plates in in the form of two half-rings fixed on the sides of the internal fixed disks, and the rotation shafts have through central holes for supplying gaseous helium lubricant under high pressure to the disks of the upper and lower plain bearings. 5. Centrifugal press flywheel according to any one of paragraphs. 1-4, characterized in that, in order to isolate the air inside the flywheel, it is equipped with a dividing screen installed inside the frame made of an elastic material of a round or oval shape, which is fixed on the outer surface of the flywheel with the possibility of rotation with it or is fixed and attached by the lower part to the frame in near the lower pole of the flywheel, and the upper part - to the upper shaft of rotation of the flywheel by means of a sliding ring, while there is a gap between the separating screen and the flywheel along its entire circumference, and the separating screen has sliding flaps to provide access to the workpiece and replace the air inside the flywheel with helium. 6. Centrifugal press flywheel containing two horizontal beams: upper and lower, between which two flywheels are installed at their edges, each of them is made in the form of a ring of steel tape wound with the possibility of free sliding of turns relative to each other, while the axis rotation of the flywheel is rotated 90° relative to the ring and parallel to the plane of the winding of the tape, and both rings have the shape of an oval elongated vertically, flywheel rotation shafts, plain bearings, taken out of the flywheels and located on the outside of the horizontal beams, steel plates, made with the possibility transmission through them of effort on the workpiece by horizontal beams from two flywheels, and hydraulic cylinders installed between the horizontal beams to support the upper horizontal beam and raise it after the end of the working cycle. 7. Centrifugal press flywheel according to claim 6, characterized in that both flywheels of the press are isolated from the environment by installing separating screens made of solid material around them, each of which is structurally made of two fixed, but at the same time sliding relative to each other sealed cylinders mounted on beams with the possibility of creating a rarefaction inside them and / or replacing air with helium. 9. Centrifugal press according to any one of paragraphs. 1, 3, 4, 6, characterized in that it is equipped with two metal supports installed in a spacer between steel plates with the possibility of their deflection to the side by means of a remote-controlled drive when the flywheel reaches the estimated number of revolutions, due to which its upper part gets the opportunity to freely move down and strike the workpiece with a steel plate. 10. A centrifugal press flywheel containing a base, a flywheel, an electric drive and steel plates, characterized in that the flywheel is made in the form of a ring of steel tape wound with the possibility of free sliding of the turns relative to each other, while the axis of rotation of the flywheel is parallel to the turns of the tape and perpendicular the plane of its winding, and the ring itself has a round or oval shape and a variable cross section, smaller at the poles of the ring and larger at its opposite parts at points spaced 90 °, and the sides of the ring with a large cross section are fixed in ring holders, which are located on a round platform with the possibility of synchronous radial movement from the center of rotation of the platform to its periphery and back, while the shaft of rotation of the platform is fixed in the base and connected to the electric drive, and the flywheel ring is configured to transfer force from its poles by means of steel plates to the workpiece.

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