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(11) | EP 0 031 324 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) |
POSITIVE PRESSURE PUMP OR MOTOR PUMPE ODER MOTOR MIT POSITIVEM DRUCK POMPE OU MOTEUR A PRESSION POSITIVE |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0001] This invention concerns a positive pressure pump or motor of the type built up from roller bodies designed to roll between two rings or discs in the same manner as those of a radial or axial ball bearing, i.e. for instance an inner ring or an outer ring, in which a pump effect is obtained by means of providing periodic variation of the tangential distance between the roller bodies during a revolution around the main axis, i.e. the mutual axis of the rings or discs, the bodies approaching each other at the delivery side and moving away from each other at the suction side. In this connection, pumps and motors are to be understood in general terms, indeed, since these designations should also cover for instance compressors, and use may be made in this connection with both liquid and gaseous media. So when the invention is described in the following sections primarily in relation to pumps, this is being done solely for convenience of language.
[0002] Pumps of the type mentioned are known from the German publication releases DE-A Nos. 2224273 and 2240950. In the case of the pumps known from these, the roller bodies are forced into positions where the mutual distance varies, despite the fact that they do at the same time roll on an inner ring and an outer ring in the same manner as that of a roller bearing. Thus, the roller bodies are forced away from pure rolling for they are forced into sliding on the roller surfaces. This, of course, will involve a friction loss, and at the same time it will cause friction surface wear. Thus, in practice these pumps cannot be run by providing a relative movement between the inner ring and the outer ring, either, since, as mentioned above, the necessary friction will vanish owing to wear. The pump according to DE-A 2240950 is driven by holding one ring stationary and transferring the rotation to the roller bodies through the means adjusting the distance between the bodies, i.e. the roller bodies are pushed round. This will, of course, entail a friction loss, too.
[0003] The purpose of the present invention is that of remedying these drawbacks, and the pump or the motor of the invention is characterised in that the means for periodic variation of the tangential distance between the roller bodies consist in that the roller bodies have decreasing cross-section in both axial directions, and that the loci of the points of contact of the roller bodies with at least one of the rings on which the roller bodies move have a varying axial spacing. In the case of a construction of this nature, there will be pure rolling between the parts moved, and the entire friction existing at the rolling points will then be available for the pressure build-up, and thus for the power transmission. Thus, it will be possible to build pumps or motors of the type referred to which will work with higher pressure and effect and be more durable, too, since there will not be the same friction surface wear as in the case of those known. Besides, the design to the invention will be greatly simplified in comparison with the designs known since it does not include a separate embedded device for producing the distance variation between the roller bodies. This device has been replaced by a special design of the roller paths for the roller bodies.
[0004] The arrangement of the invention is comparatively simple to manufacture. For instance there is no need to provide bearings since the pumping parts will provide the necessary control of the rotating parts in relation to the fixed ones.
[0005] One embodiment of the invention, mainly built up as a radial bearing, i.e. with an outer ring and an inner ring, is characterized in that the roller surface on the inner ring is shaped as a surface of revolution, in that the inner ring has been connected to a driving shaft or a driven shaft, and in that the outer ring design has been maintained in a stationary casing. Thus, an expediency of design is attained to which the part containing the modified roller surfaces and determining the positioning of the inlet and the outlet has been placed under the non-rotating part.
[0006] A further development of this embodiment is characterized in that the outer ring is made up to two rings lying beside each other. This design is simple to produce.
[0007] A further development of this embodiment is characterized in that it has means for pressing the two outer rings axially against each other, for instance a spring. Thus, compensation for roller surface wear is provided.
[0008] Another embodiment is characterized in that between each successive pair of roller bodies a loose filling-in body has been placed of a size sufficient for substantially filling in the space between the two roller bodies when these are in the position where the tangential distance between them is at its minimum and in that the outline of a roller body and a filling-in body, when viewed in the tangential direction, is more or less the same. Thus, unwanted space may be avoided and at the same time the minimum distance between the roller bodies can be controlled.
[0009] A third embodiment is characterized in that the roller bodies are balls embedded between an inner ring and an outer ring. This allows for low cost production since standard bearing ball designs may be used, made with fine tolerances and at a low price.
[0010] A fourth embodiment is characterized in that the roller bodies are barrel-shaped, in that the ring design is made up of an inner ring and two outer rings with cone-shaped inner roller surfaces which at two symmetric points bear against each barrel-shaped roller body, in that an elastic deforming sealing ring has been inserted between the two outer rings, and in providing means of tipping the axes for each of the two outer rings in relation to the main axis both one way and the other in which case the inner ring has been designed to rotate whereas the outer rings are being detained against rotation. By adjusting the outer rings at a constant number of revolutions, this design will allow for adjustment of the flow continuously both one way and the other.
[0011] This invention is explained further with reference to the drawings where:
Figure 1 shows a radial section through an embodiment of a pump according to the invention along a section line A-A in Figure 2.
Figure 2 is a section between the pump to the line B-B in Figure 1,
Figure 3 an axial section through another embodiment not showing, however, certain parts, and
Figure 4 an axial section through a third embodiment in the same manner as that of Figure 3.
[0012] The design shown in Figures 1 and 2 is that of a pump mainly built up as a radial ball bearing. The individual elements bear the same reference numbers in the two figures. In a stationary casing 1 an outer ring configuration has been secured, consisting of two rings 2 and 3, these rings being held by a cover 4. Inside rings 2 and 3 balls 5 and 6 have been placed. On the inner sides, the balls bear against an inner ring 7 mounted on a driving shaft 8 protruding through the casing 1 with interposition of a packing 9. In the casing 1 or in the cover 4, an inlet passage (not shown) and an outlet passage (not shown) have been provided. Finally, filling-in bodies 10 of a special shape have been inserted between successive balls 5 and 6. The surfaces of the filling-in bodies 10 facing the balls are concave spherical surfaces of the same radius as those of balls 5 and 6. Further, the filling-in bodies 10 viewed in the tangential direction are shaped as circles of the same radius as that of the balls. Part 11 in Figure 2 is thus a filling-in body. The outer rings 2 and 3 together form a roller surface of a special shape. Solely production-technical considerations are behind the fact that the outer ring design consists of two rings 2 and 3. The shape of the surface at the top and at the bottom in Figure 2 thus represents extremes. At the bottom of Figure 2, the roller surface has been shaped so that the contact point is at the reference sign 12, a fact actually illustrating something known since a ball at this point will then move at an angular velocity of half that of the inner ring when retaining the outer ring. This is a question of the angular velocity of a ball in its planetary motion. On the other hand, at the top of Figure 2 the roller surface has been shaped so that the ball will roll at two symmetric contact points 13 and 14 lying at a lesser radius than that of the contact point 12. At this point the balls will thus have an angular velocity less than half the angular velocity of the inner ring. Between these two extremes of the shape of outer rings 2 and 3, at the top and at the bottom of Figure 2, respectively, the shape of the outer ring grooves gradually merges from one form to the other. The loci of the points of contact between the balls and the grooves are thus shaped as two closed curves meeting or touching each other at point 12 at the bottom of Figure 2. Thus, it would seem clear that a given ball on its way round along the outer rings will be in planetary motion, showing a growing velocity at one half of the circumference and a declining velocity at the other half of the circumference. Thus, over one half of the circumference the distance between the balls will thus decrease whereas the distance will increase over the other half. One side where the balls are converging, will be the pressure side and the other will be the suction side.
[0013] The filling-in pieces 10 serve to reduce the unwanted space and to maintain the minimum distance between the balls. As would appear, theoretically there will be no unwanted space when using filling-in pieces of the shape described.
[0014] Figure 3 shows another embodiment to which parts corresponding to the parts of Figure 2 bear the same reference numbers. In addition to that, this design differs from the former in that the casing 1 has been fastened against another casing 20 which may be a motor housing by means of stay bolts 21. In this Figure 3, connection bores 22 and 23 have also been shown, constituting the pump inlet and discharge. The two outer rings 2 and 3 have been spring-loaded against each other in axial direction by means of a disc spring 24, thus compensating for the wear which balls and rings are exposed to. An elastic sealing ring 25 has been inserted between the rings 2 and 3. It will be possible for the two outer rings to be pressed against each other in a different way, for instance by means of the hydraulic pressure produced by the pump.
[0015] Figure 4 shows a design equal to the former ones where the corresponding parts bear the same reference numbers. The roller bodies 30 are barrel-shaped. The roller surfaces on the outer rings 2 and 3 are conical, and no means of tilting the outer rings 2 and 3 in relation to each other have been shown; these means may be conventional screws. Thus, adjustment of the volume flow to a given number of revolutions is made possible. In the case of this design, the roller bodies could on the other hand have been shaped as reversed truncated cones, the bases against each other, whereas the roller surfaces on outer rings 2 and 3 could have been double curved. Elastic seal rings 31, 32 and 33 have been inserted between rings 2 and 3 and the rings in the casing. Since outer rings 2 and 3 have been designed to tilt around axes at right angles to the plane of the paper and through the longitudinal axis, it will not be expedient to press rings 2 and 3 against each other by means of disc springs. Consequently a pair of springs has been placed lying diametrically opposite each other at a level at right angles to the plane of the paper and containing the longitudinal axis out of which one has been shown in Figure 4 and bears reference number 34. The ends of spring 34 may be attached to protruding pins 35 and 36.
1. A positive pressure pump or motor of the type built up from roller bodies (5) designed
to roll between two rings (2, 3 and 7) in the same manner as those of a radial ball
bearing, in which a pump effect is obtained by means of providing periodic variation
of the tangential distance between the roller bodies during a revolution around the
main axis, i.e. the mutual axis of the rings, the bodies approaching each other at
the delivery side and moving away from each other at the suction side, characterised
in that the means for periodic variation of the tangential distance between the roller
bodies (5) consist in that the roller bodies (5) have decreasing cross section in
both axial directions, and that the loci of the points of contact of the roller bodies
with at least one of the rings (2, 3 and 7) have a varying axial spacing.
2. A pump or motor according to claim 1, built up as a radial bearing, i.e. with an
outer- ring (2, 3) and an inner ring (7), characterised in that the roller surface
on the inner ring (7) is shaped as a surface of revolution, in that the inner rings
have been connected to a driving shaft or a driven shaft (8) and in that the outer
ring has been maintained in a stationary casing (1).
3. A pump or motor according to claim 2, characterised in that the outer ring is made
up of two rings (2 and 3) lying beside each other.
4. A pump or motor according to claim 3, characterised in that it has means for pressing
the two outer rings (2, 3) axially against each other, for instance a spring (34).
5. A pump or motor according to claims 1, 2, 3 or 4, characterised in that between
each pair of successive roller bodies (5, 6) there is located a loose filling-in body
(10) of a size sufficient for substantially filling in the space between the two roller
bodies (5, 6) when these are in the position where the tangential distance between
them is at its minimum and that the outline of a roller body and a filling-in body,
when viewed in the tangential direction, is substantially the same.
6. A pump or motor according to claims 2, 3, 4 or 5, characterised in that the roller
bodies (5, 6) are balls embedded between an inner ring (7) and an outer ring (2, 3).
7. A pump or motor according to claims 1, 2 or 5, characterised in that the roller
bodies (30) are barrel-shaped in that the rings comprise an inner ring (7) and two
outer rings (2, 3) with cone-shaped inner roller surfaces which at two symmetric points
bear against each barrel-shaped roller body, in that an elastic deformable sealing
ring (32) has been inserted between the two outer rings, and in that means is provided
for tipping the axes of each of the two outer rings (2, 3) in relation to the main
axis both one way and the other in which case the inner ring has been designed to
rotate whereas the outer rings are restrained against rotation.
1. Pompe ou moteur à pression positive du type constitué de corps de roulement (5)
conçus pour rouler entre deux bagues (2, 3, 7) de la même manière que ceux d'un roulement
à billes radial, dans lequel on obtient un effet de pompage en prévoyant une variation
périodique de la distance tangentielle entres les corps de roulement pendant une révolution
autour de l'axe principal, c'est-à-dire l'axe commun des bagues, les corps s'approchant
l'un de l'autre du côté du refoulement et s'écartant l'un de l'autre du côté de l'aspiration,
caractérisée en ce que les moyens prévus pour la variation périodique de la distance
tangentielle entre les corps de roulement (5) sont constitués par le fait que les
corps de roulement (5) ont une section transversale décroissante dans les deux directions
axiales, et par le fait que les lieux des points de contact des corps de roulement
avec au moins l'une des bagues (2, 3, 7) ont un espacement axial variable.
2. Pompe ou moteur selon la revendication 1, constituée comme un roulement radial,
c'est-à-dire avec une bague extérieure (2, 3) et une bague intérieure (7) caractérisée
en ce que la surface de roulement sur la bague intérieure (7) a la forme d'une surface
de révolution, en ce que les bagues intérieures ont été reliées à un arbre entrainant
ou à un arbre entrainé (8) et en ce que la bague extérieure a été maintenue dans un
boitier stationnaire (1).
3. Pompe ou moteur selon la revendication 2, caractérisée en ce que la bague extérieure
est constituée de deux bagues (2, 3) reposant l'une à côté de l'autre.
4. Pompe ou moteur selon la revendication 2, caractérisé en ce qu'il comporte des
moyens pour presser les deux bagues extérieures (2, 3) axialement l'une contre l'autre,
par exemple un ressort (34).
5. Pompe ou moteur selon les revendications 1, 2, 3 ou 4, caractérisé en ce qu'entre
chaque paire de corps de roulement successif (5, 6) est disposé un corps libre (10)
de remplissage d'une dimension suffisante pour remplir substantiellement l'espace
entre les deux corps de roulement (5, 6) lorsque ceux-ci sont dans la position pour
laquelle la distance tangentielle entre eux est à son minimum et en ce que le contour
d'un corps de roulement et celui d'un corps de remplissage sont essentiellement les
mêmes lorsque l'on regarde dans la direction tangentielle.
6. Pompe ou moteur selon les revendications 2, 3, 4 ou 5, caractérisé en ce que les
corps de roulement (5, 6) sont des billes noyées entre une bague intérieure (7) et
une bague extérieure (2, 3).
7. Pompe ou moteur selon les revendications 1, 2 ou 5, caractérisé en ce que les corps
de roulement (30) sont en forme de tonneau, en ce que les bagues comprennent une bague
intérieure (7) et deux bagues extérieures (2, 3) avec des surfaces de roulement intérieur
en forme de cône qui s'appuient en deux points symétriques contre chaque corps de
roulement en forme de tonneau, en ce qu'on a inséré une bague d'étanchéité (32) élastique
et déformable entre les deux bagues extérieures et en ce que on a prévu des moyens
pour incliner les axes de chacun des deux bagues extérieures (2, 3) par rapport à
l'axe principal, à la fois dans une direction et dans l'autre, auquel cas la bague
intérieure a été conçue pour tourner alors que les bagues extérieures sont empêchées
de tourner.
1. Pumpe oder Motor mit positivem Druck, aus Wälzkörpern (5), die zwischen zwei Ringen
(2, 3 und 7) wie in einem Radiallager laufen, wobei die Pumpwirkung durch periodische
Variation des tangentialen Abstandes zwischen den Wälzkörpern beim Umlauf um die Hauptachse,
d.h. um die gemeinsame Achse der Ringe, erreicht wird und die Wälzkörper sich an der
Druckseite einander nähern sowie sich an der Saugseite voneinander entfernen, dadurch
gekennzeichnet, daß zum Zwecke per periodischen Veränderung des tangentialen Abstandes
zwischen den Wälzkörpern (5) diese in beiden axialen Richtungen abnehmende Querschnitte
aufweisen und daß die Berührungspunkte der Wälzkörper (5) mit wenigstens einem der
Ringe (2, 3 und 7) veränderliche Abstände zur Hauptachse aufweisen.
2. Pumpe oder Motor nach Anspruch 1 in Form eines Radiallagers mit einem Außenring
(2, 3) und einem Innenring (7), dadurch gekennzeichnet, daß die Wälzfläche des Innenringes
als Umdrehungsfläche ausgebildet ist, daß der Innenring mit einer angetriebenen Welle
oder einer Antriebswelle (8) verbunden ist und daß der Außenring in einem stationären
Gehäuse (1) gehalten ist.
3. Pumpe oder Motor nach Anspruch 2, dadurch gekennzeichnet, daß der Außenring aus
zwei nebeneinander angeordneten Ringen (2 und 3) besteht.
4. Pumpe oder Motor nach Anspruch 3, gekennzeichnet durch eine Einrichtung zum Zusammenpressen
der beiden äußeren Ringe (2, 3) in axialer Richtung, insbesondere eine Feder (34).
5. Pumpe oder Motor nach einem der Ansprüche 1-4, dadurch gekennzeichnet, daß zwischen
jedem Paar aufeinanderfolgender Wälzkörper (5, 6) ein loser Füllkörper (10) angeordnet
ist, der eine Größe besitzt, die ausreicht, den Raum zwischen den beiden Wälzkörpern
(5, 6) auszufüllen, wenn diese sich in einer Position befinden, bei der ihr tangentialer
Abstand ein Minimum ist, und daß die Profile eines Wälzkörpers und eines Füllkörpers,
in tangentialer Richtung gesehen, im wesentlichen übereinstimmen.
6. Pumpe oder Motor nach einem der Ansprüche 2-5, dadurch gekennzeichnet, daß die
Wälzkörper (5, 6) Kugeln sind, die zwischen einem Innenring (7) und einem Außenring
(2, 3) gelagert sind.
7. Pumpe oder Motor nach einem der Ansprüche 1, 2 oder 5, dadurch gekennzeichnet,
daß die Wälzkörper (30) tonnenförmig ausgebildet sind, daß ein Innenring (7) und zwei
äußere Ringe (2, 3) mit konischen Wälzflächen vorgesehen sind, die jeden tonnenförmigen
Wälzkörper an zwei zueinander symmetrischen Pumpen abstützen, daß ein elastisch deformierbarer
Dichtring (32) zwischen die beiden äußeren Ringe eingelegt ist und daß eine Einrichtung
zum Kippen der Achsen jedes der beiden äußeren Ringe (2, 3) in beiden Richtungen relativ
zur Hauptachse vorgesehen ist, wobei der Innenring rotiert, während die aüßeren Ringe
drehfest gehalten sind.