Spring barrel pumps

Abstract

Spring barrel pump characterized by the fact that the bores (2) in which the pistons (4) move are provided by way of the spring barrel (1) diametrically to its axis (XX).

Description

This invention has as its object a rotating spring barrel pump in which the pistons move into bores provided through the spring barrel, diametrically to its axis, by moving away under the effect of the centrifugal force and by drawing closer by resting on an eccentric ring.

Such pumps are known by the patents WO 02/084105 of Oct. 24, 2002; US 2004/065192 of Sep. 17, 2003; DE 198 42 120 of Sep. 21, 1998; DE 36 28 769 of Aug. 25, 1986 and EP 0 812 985 of Jun. 3, 1997.

These known pumps all have the drawback of using complex means to ensure the supplying and the conveying of the oil, which in practice prevents their use for high turning speeds of the spring barrel and therefore limits the usage thereof.

The pump according to the invention comprises both very simple and particularly high-performing supplying and discharging means that allow its use at very high turning speeds of the spring barrel.

The pump according to the invention is a rotating spring barrel pump in which the pistons move into bores provided diametrically through said spring barrel by moving away under the effect of the centrifugal force and by drawing closer by resting on an eccentric ring, characterized by the fact that said bores communicate: on the one hand with the supply duct by means of ducts emptying into a chamber that is located behind the rotating spring barrel, a chamber into which the supply duct empties; on the other hand, with the conveyor duct by means of a collector, applied against the rear surface of said spring barrel by a spring, whereby this collector is equipped with a cup that communicates with said conveyor duct; whereby said collector is eccentric relative to the axis of the spring barrel such that each of the ducts empties into said chamber during a half-turn and into the cup during a half-turn.

By way of nonlimiting example and to facilitate the comprehension of the invention, the following was shown in the accompanying drawings:

FIG. 1: A longitudinal cutaway view of an embodiment of the invention.

FIG. 2: A view on an enlarged scale of a portion of FIG. 1, whereby the parts are in median position.

FIG. 3: A view corresponding to FIG. 2, after a rotation of 90°.

FIG. 4: A cutaway view along BB of FIG. 1.

By referring to these figures, it is seen that the pump that is indicated by the general reference P is driven by a motor M.

The pump P consists of a spring barrel 1 that, in the example shown, is a full cylindrical body, whose end 1a is traversed, along a diameter, by a bore 2.

This bore 2 is separated into two equal portions 2a, 2b by a plug 3 that is placed on the axis XX of the spring barrel 1.

In the bores 2a, 2b, two cylindrical flyweights 4a and 4b, which project slightly beyond the rear cylindrical portion 1a of the spring barrel 1, slide freely.

The ends of the flyweights 4a, 4b that project beyond the spring barrel 1a rest against a circular ring 5.

As is seen in FIG. 3, this ring is eccentric relative to the axis XX.

This pump is designed to be driven at very high speeds, on the order of 25,000 rpm.

At such speeds, the flyweights 4a, 4b are moved away from the axis XX by the centrifugal force and are brought toward the center by the ring 5, which is eccentric: this back-and-forth movement of the flyweights 4a, 4b produces a pumping effect, whereby said flyweights act as pistons.

It is necessary that the hydraulic fluid can return into the bores 2 during the spacing movement of the flyweights/pistons 4 and can be evacuated under pressure when these flyweights/pistons 4 are pushed back by the ring 5.

For this purpose, the bores 2a and 2b are each connected by a pipe 6a, 6b to a chamber 7 into which the hydraulic fluid enters via an intake pipe 8.

A conveyor collector 9 is applied by a spring 10 against the flat rear surface 11 of the rear portion 1a of the spring barrel 1.

The end of said conveyor collector 9 that rests against the surface 11 comprises a cylindrical cup 12 that communicates with a discharge duct 13.

As is indicated in FIG. 2 by the broken line Z, the axis of the cup 12 is eccentric relative to the axis XX of the spring barrel 1.

As is seen by comparing FIGS. 2 and 3, the result is that when the spring barrel 1 executes a rotation, in a first step, a half-turn, during which the piston 4a moves away under the effect of the centrifugal force, the duct 6a communicates with the chamber 7, and the hydraulic fluid is drawn into the bore 2a; then, in a second step, second half-turn, when the piston 4a is pushed by the ring 5, which is eccentric, the fluid is conveyed from the bore 2a by the duct 6a that then is found in correspondence with the cup 12 because the latter is eccentric.

Thus, at each turn, the hydraulic fluid is drawn in and then fed back.

Furthermore, it is easy to act on the eccentricity of the ring 5 and thus to obtain a variable-capacity pump.

Preferably, the ring 5 consists of a roller bearing, whereby the ends of the pistons 4 rest against the inside ring of said roller bearing.

This inside ring is driven in rotation by the support exerted by the pistons, with a slight sliding of the latter.

A pump, such as the one shown in FIGS. 1 to 3, can be driven up to 20,000 rpm and more without it being necessary to pressurize the supply of the pump, and it can provide pressure up to 700 bar.

All of the forces are radial forces, which makes it possible to use common, less expensive means to ensure the sealing.

The collector 9 is preferably constituted to be hydrostatically balanced, whereby the surface area of its rear face is slightly larger than that of the cup 12 and whereby the only object of the spring 10 is to ensure correct operation without pressure or at very low conveyor pressure.

In the example shown, a single bore 2 passes through the spring barrel 1, but it is possible to use several bores that are each equipped with two pistons.

This invention makes it possible to produce a pump that has remarkable qualities with simple and inexpensive mechanical means.

Claims

1. Spring barrel pump of the type in which the pistons (4) move into bores (2a, 2b) provided through said spring barrel (10), diametrically to its axis (XX), by moving away under the effect of the centrifugal force and by drawing closer by resting on an eccentric ring (5), characterized by the fact that said bores (2a, 2b) communicate: on the one hand, with the supply duct (8) by means of ducts (6a, 6b) emptying into a chamber (7) that is located behind the spring barrel (1) into which said duct (8) empties; on the other hand, with the conveyor duct (13) by means of a collector (9), applied against the rear surface (11) of the spring barrel (1) by a spring (10), whereby this collector (9) is equipped with a cup (12) that communicates with said conveyor duct (13); whereby said collector (9) is eccentric relative to the axis (XX) of the spring barrel (1), such that each of the ducts (6a, 6b) empties into the chamber (7) during a half-turn and into the cup (12) during a half-turn.

2. Pump according to claim 1, wherein the collector (9) is balanced hydrostatically so as to be kept—by pressure—resting against the rear surface (11) of the spring barrel (1).

3. Pump according to claim 1, wherein the pump is a variable-capacity pump.