DE2524586A1 - POWER TRANSMISSION DEVICE - Google Patents

Description

Patent attorneys Dipl.-Ing. H. Weickmann, Dipl.-Phys. Dr K. Fincke

Dipl.-Ing. F. A. Weickmann, Dipl.-Chem. B. Huber

8 MUNICH 86, DEN

PO Box 860 820

MDHLSTRASSE 22, CALL NUMBER 98 39 21/22

HYDRAULIC PRODUCTS INCORPORATED, 79oo Durand Avenue, Stürtevant, Wisconsin, V.St.A.

Power transmission device

The present invention relates to a bidirectional gerotor type power transmission device, and more particularly to one Device that works either as a hydraulic motor or as a pump.

They are power transmission devices of the gerotor type known in which the achievement of radial equilibrium of the outer element is attempted in a way as they is shown, for example, in US Pat. No. 3,427,983. The inadequacies of this attempt are listed in a later U.S. Patent 3,680,989. In a device of the gerotor type are the forces generated both in size and in

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Direction variable, since the working area on the inner part of the outer gear element is based on two movable sealing points and on the timing with respect to the fluid or liquid passage that defines the space between the
Gear elements supplied, is based. This range changes in frequency and size, with the frequency
a function of the number of teeth on the inner gear member times its speed of rotation and the size is a function of the geometry of the inner and outer gear members. aside from that
the force acting on the outer gear element results in a rotation of the outer gear element with respect to one another
on the housing about a generally fixed point which creates minimal space in the free area surrounding the outer gear member. This location changes with the variation in the magnitude and direction of the forces generated in the operation of the device.

Attempts have been made to balance the outer gear member by having a plurality of
Set outside the outer gear element, a working pressure is passed. Doing so will vary the size
and the direction of the forces are not taken into account.

To solve these problems, it is also proposed to achieve a radial balance for the outer gear element by using a hydrodynamic sleeve bearing effect in which a fluid, ie a gas or a
Liquid, (in the following, for the sake of simplicity only
be talking about liquid), in the free space between
the outer gear element and the housing can flow,

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namely in the direction of rotation of the outer gear element and with a pressure formation that depends on the forces, with which the outer gear element is pressed against the housing. This proposed solution is only suitable for one-way operation.

The object of the invention is to create a force transmission device that acts in two or in both directions, in which an outer gear member of a gerotor type device by means of a hydrodynamic sleeve bearing effect is kept radially in equilibrium in each of the two directions of rotation of the device.

According to the invention, this object is achieved by means of a power transmission device solved with the IJerkmalen of claim 1. The outer gear element is of the gerotor type Device arranged within a housing. Located between the outer gear element and the housing is a free space connected to a liquid inlet along a line that passes through the generally coincides with the axis of rotation of the inner gear member, with the pivot point for the outer Gear element together with a liquid outlet from the clearance is diametrically opposed to the liquid inlet; Valve devices react to the fluid pressure, around the liquid inlet with one of the two housing passages for the device that receives the liquid pressure and the liquid outlet with the other of the housing passages connected to the 'i' tank is to connect.

iiit the location of a liquid inlet and a liquid outlet regarding a leeway in the outside

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Gear element of the power transmission unit surrounding the housing, it is possible to use a hydrostatic
Pressure gradients when the device is initially started as a motor and a hydrodynamic pressure during
the normal operation of the device as a pump or motor to achieve radial balance of the outer gear element and to absorb variable loads resulting from a displacement resultant of the forces acting around the pivot point of the outer gear element and deflections of the shaft on which the inner gear element is mounted to counteract it, especially at high operating pressures. It can be assumed that the operating pressure is in the order of magnitude of
352 kg / cm ² .

Advantageous further developments of the invention are set out in the subclaims contain.

The invention is explained in more detail below with reference to the figures. Show it:

Fig. 1 is a central planar section of the bidirectional power transmission taken along line 1-1 in
Fig. 2;

Fig. 2 is a vertical section along the line 2-2 in Fig. 1;

Fig. 3 is a graph showing the relationship of the hydrostatic pressures at various points the outer gear element and at two different values of the supply pressure;

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FIG. 4 is a representation similar to that of FIG. 3 showing the relationship of hydrodynamic pressures at two different Shows supply pressures;

Fig. 5 is a schematic view of the power transmission device as an engine when stationary;

6 shows a schematic view of the power transmission device as an Iotor in operation in one direction of rotation; and

Fig. 7 is a view similar to that of Fig. 5, the device serving as a pump.

The bidirectional power transmission is in the 1 to 6 are shown as a motor and have a housing 1o with a central part 11 which has a cylindrical chamber 12 delimits, as well as with a pair of cover blocks 14 and 15, which on either side of the plate or the central part 11 are arranged; the housing is held together by a row of bolts or studs 16. The power transmission device is of the gerotor type in which an inner gear member 2o is within an outer gear member 21 is arranged. The inner gear member 2o is mounted on a shaft 22 and rotatable therewith; the shaft is carried by bearings 23 and 24 in the housing. The inner wall of the cylindrical chamber 12 is opposite the axis of rotation of the shaft 22 and the inner gear element 2o offset eccentrically. This is the case with a hydraulic one i.power transmission device of the gerotor type known. With the six teeth 25 on the inner gear element 2o and the seven internal teeth 26 on the outer gear member 21 becomes a plurality of liquid chambers formed in the space between the gear elements.

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The housing 1o has a pair of opposing housing passages 3o and 31 for / connection to a pressure fluid supply and a drainage container, the connections being reversible when the power transmission device is shown in can work two directions. In the schematic views of FIGS. 5 and 6, it is assumed that the housing passage 3o are connected to a pressure fluid source and the housing passage 31 is connected to a drainage container. The housing passages 3o and 31 are connected to one another by connecting channels which contain a flow channel 4o, which ends in a kidney-shaped liquid passage 41; this causes liquid under pressure to become too Fluid chambers are provided which are formed between the inner and outer gear members. The connecting channels contain a second flow channel 42, which extends from the Housing passage 31 extends and terminates in a kidney-shaped liquid passage 43, whereby liquid flowing from certain fluid chambers between the inner and the outer gear member is discharged, to the housing passage 31 can flow.

As shown in Fig. 5, one tooth meshes with the inner gear member with two teeth 26 of the outer gear element to form an intersection area between the pressure side and the drain pan side of the facility, while a second intersection area is formed by the surfaces the tips of a tooth 25 of the inner gear member and a tip of a tooth 26 of the outer gear member engage with each other. The kidney-shaped liquid passages 41 and 43 lie between these intersection areas.

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The diameter of the outer gear element 21 is smaller than that of the cylindrical Kanmer 12, so that there is a free space 45 between them. Thus, the linrichtung the Letriebseigenschaften a high Startdrehraonents and a radial balance during operation v / eist, liquid is supplied in the free space 45 to flow around to the outer gear element and flow away from the free space to the drain container. This is achieved in that a liquid inlet 46 is provided to the free space, which is formed by a groove in the housing plate or in the central part 11, which is in communication with a groove 47 on a surface of the central part 11 and extends to the upper and lower Extends valve bores 48 and 49, which are connected to the flow channels 4o and 42 to thereby form the connecting channels which connect the housing passages 3o and 31 with each other. A pair of pressure sensitive valves are disposed in the valve bores 48 and 49 and in particular contain a pair of check valves 50 and 51 which are spring loaded by springs 52 and 53, respectively, to rest against associated valve seats and to open in response to the fluid pressure. As from the schematic view of / Fig. 5, the shut-off valve 51 opens depending on the pressure at the housing passage 3o and in the flow channel Ίο to deliver pressurized fluid to the liquid inlet 46, while the associated shut-off valve 5o prevents the fluid inlet from being connected to the housing passage 31. With the pair of check valves 5o and 51 it is possible to operate the power transmission device in two directions, one of the housing passages 3o or 31 being connected to a pressurized fluid source in order to supply pressurized fluid to the fluid inlet 46 and thus to the free space 45.

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Liquid flows from free space 4 5 through a liquid outlet 60, which is designed as a hat in the central part 11 is and via a passage 61 with a space 62 in the housing block 15, which surrounds the shaft 22, connected is. This space communicates with the flow channels 40 and 42 via a pair of channels 63 and 64 (FIG. 2), each of which coupled to a pressure sensitive valve in the form of check valves 65 and 66; the check valves 65 and 66 are turned into one of their respective springs 67 and 6S Direction pressed that the connection of the space 62 with the flow channels 4o and 42 is closed. The backs of the Check valves 65 and 66 are exposed to flow channels 4o and 42, thereby eliminating the presence of pressurized liquid in one of these flow passages The associated shut-off valve remains closed. In the working direction that is assumed here, there is a Liquid pressure in the flow channel 4o, whereby the shut-off valve 66 is kept closed, while the pressure of the free space 45 flowing liquid is sufficient to lift the shut-off valve 65 from the valve seat and to enable that liquid flows to the flow channel 42 which is connected to the drainage container.

The hydrostatic and hydrodynamic pressures that occur when setting up ensure good starting properties and a To maintain radial equilibrium during operation are shown in the curves in Figures 3 and 4. In each of these Figures 3 and 4 is a full line pressure curve for operation at a relatively high pressure and a pressure curve shown in dashed line for operation at a lower pressure supply, with the dots along the abscissa of the illustration, which are designated by A to H, the circumferential locations identified in FIGS. 5 and 6 correspond. The hydrostatic pressures are

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Shown in Fig. and are at the time of delivery the liquid inlet 46 at the value shown at point Λ. The pressure drops progressively to point C and remains to a relatively low i; ert up to a point briefly before point H. The hydrostatic pressure arises from the fact that the negative pressure oil to the liquid inlet 46 and then flows to points C and G in both directions as indicated by the arrows in FIG. The amount this flow is a function of the clearance of the free space, the system pressure and the capacity. When the outer gear member 21 begins to rotate, it first climbs onto the wall of the cylindrical chamber in a direction opposite to the clockwise direction of rotation of FIGS. 5 and 6. This creates the free space or the clear Width limited on one side of the outer gear element, which results in a greater flow from Λ to G than from A to C. This differential flow rate causes the pressure gradient due to the flow differences between A and B is greater than between A and H, resulting in a balance of the outer Gear element leads.

When considering the hydrodynamic pressures is note that the forces resulting from the pressure acting in the fluid chambers of the device are fundamental act in the direction of arrow 7o in Fig. 6, but with changes in direction, as mentioned above. This force causes the outer gear element 21 to pivot, about a point 72 which is fixed with respect to the housing in all rotational positions of the gear element; this results in the outer gear element being urged against the VJand of the cylindrical chamber 12 in one direction, which is generally indicated in FIG. 6 by the arrow 74. The fluid inlet 46 to the free space is at

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Creation of a maximum storage area in both directions of rotation the device on a line, the pivot or pivot point 72 and the axis of rotation which includes Uelle 22, and sufficiently before the minimum free space between points B and C in FIG. 6 and generally in the region of arrow 74.

In the opposite direction of rotation, the minimum clear width or the minimum free space between points C and H. For the direction of rotation shown in Fig. 6 it can be seen from the diagram of Fig. 4, that between points B and C a pressure is built up, which counteracts the forces that try to to rotate outer gear member 21 against the wall of the cylindrical chamber. Hence the hydrodynamic pressure the outer gear element radially in balance or equilibrium, while the hydrostatic pressure is lower. It is inherent in the hydrodynamic sleeve bearing effect that the peak value of the pressure shown in the diagram of Fig. 4 between points B and C, along the circumference of the cylindrical chamber 12 changes when the position of the arrow 74, which indicates the direction of rotation, changes. Hence the hydrodynamic delivers Bearing effect inherently a radial balance, although the resultant force shown by arrow 7o according to a Changes in the nature of a device of the gerotor type. The karves of Fig. 4 change depending on the viscosity the liquid, the clearance and the speed of rotation of the device. The pressure peak shifts toward point C as the viscosity increases and the clear 'vieite is decreasing. When the speed is increased, the pressure peak is due to a greater flow through the free space resulting from fluid being carried around the outer gear member,

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- 11 when the outer gear element rotates, wider.

From the foregoing it should be clear that in the case that the housing passage 31 are connected to the pressure and the housing passage 3o with the drainage container, the Check valve 5o opens to deliver pressurized liquid to liquid inlet 46 while the check valve 51 is closed in order to block the connection with the housing passage 3o. The check valve 65 is held closed by the pressure in the flow channel 42, while the check valve 66 is opened to allow liquid from Liquid outlet 6o can flow to the housing passage 3o.

This structure becomes a bidirectional power transmission device created in which in each of the working directions liquid is supplied to the free space to a hydrostatic Pressure at standstill and when starting the device and a hydrodynamic pressure when operating at different To achieve speeds and loads, the point of maximum pressure depends on the displacement the forces acting on the outer gear element shifts.

The preceding description of the structure shown in FIGS. 1 to 6 referred to a Hotor having a shape represents a bidirectional power transmission device. The desire for a radial balance of the outer gear element is equally applicable to a gerotor-type pump. Basically, the term power transmission device in the description and claims include both motors and pumps. With a pump there is no opposing forces during starting operation as there is no initial load on the gearwheel elements / sin. During normal rotation

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however, the same reaction force on the outer gearwheel occurs as that of the hydrodynamic bearing effect is balanced.

Fig. 7 is a view similar to Fig. 5 schematically showing a power transmission device connected to valves for pump operation. In Fig. 7, parts which correspond to those in Fig. 5 are indicated by the same reference number and an apostrophe added. It can be seen that the direction of rotation of the unit is the same as in FIG. 5, the housing passage 3ο ^{1 being} connected to a liquid supply and the housing passage 31 'being connected to the pressure outlet passage. The position of the two pairs of shut-off valves is reversed, with the shut-off valves 5ο ¹ and 51 'acting in opposition to the pressure states at the housing passages 3o' and 31 '. In the working direction shown in Fig. 7, the shut-off valve 5o 'opens so that liquid flows to the hat 6ο ¹ , which now serves as a liquid inlet. In the other working direction than the pump, the shut-off valve 51 'opens so that there is a flow from the housing passage 3ο ¹ to the groove 6ο ¹ .

The second pair of check valves 65 'and 66' are used to a flow from the rage 46 'to the housing passage 3o' or 31 ', whichever is at the lower pressure.

Another possibility of adapting the disclosed structure to a bidirectional pumping operation would consist in a change the eccentricity of the outer gear member 21. With particular reference to Figure 2, point Π represents the center of rotation of the outer gear member within of the housing in the case of the ilotoroperlebs. In comparison with the disclosure in FIGS. 1 to 6, unchanged Valve arrangement could include the chamber 12 in the central part 11 of the

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Changed the housing so that the pump operation a center of rotation P for the outer gear member 21 results.

it

It should be noted that there are several different designs for a gerotor-type power transmission device. The particular embodiment disclosed related to cream ratio 6-7. Tooth ratios of 8-9 ₇ 10-11 and 12-13 are also known, and there are other possible variations. The basic principle that these designs have in common is the low relative speed between the cooperating surfaces of the inner and outer gear elements.

With respect to the inner and outer gear elements should structures dei ^ kxt are within the scope of the invention, such as they are shown in U.S. Patent 3,623,829, the inner gear member having outer teeth, which are in the form of spherical elements.

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Claims (9)

Claims: Bidirectional power transmission device, marked by: a: housing (1o) with a cylindrical chamber (12), partially meshing inner and outer gear elements (2o, 21) rotatably mounted in the chamber, a there is free space between a wall of the chamber and the outer periphery of the outer gear member (21), wherein the gear elements are in an eccentric relationship to form a series of fluid chambers and wherein the Teeth of the gear elements at two intersection areas are in interaction, in which a fluid connection between the liquid caramers on both sides of the crossing areas are blocked, a pair of kidney-shaped liquid passages (41, 43) in the Housing between the crossing areas, a pair of flow channels (4o, 42) with respective passages are connected, a pressurized fluid inlet (46) for the free space which is circumferentially between the fluid passages and connected to the flow channels, a pressure fluid outlet (6o), from the free space, the is diametrically opposite the pressure fluid inlet and is connected to the flow channels, and by valve means (5o, 51; 65, 66) around only one of the flow channels in connection with the pressure fluid inlet and to place the other of the flow channels in communication with the pressurized fluid outlet. 2) power transmission device according to claim 1, characterized in that that the valve devices (5o, 51; 65, 66) 15 - 60981 1/0227 are pressure dependent. 3) power transmission device according to claim 2, characterized in that that the valve means contain a first and a second pair of check valves (5o, 51; 65, 66), being a couple a river from the free scarcely (45) and between the flow channels (4o, 42), while the other pair allows a flow of free space between blocked the river channels. 4) Gerotor type bidirectional hydraulic motor, labeled by: a housing (1o), an inner gear member (2o) and an outer gear member (21) rotatably mounted in the housing, wherein the outer gear element is arranged eccentrically with respect to the inner gear element, so that a series of Liquid chambers formed between the gear elements and v / obei the teeth of the cogwheel elements interact at zv / ei intersection areas, creating a fluid connection is blocked between the fluid chambers on both sides of the crossing areas, a pair of kidney-shaped fluid passages (41, 43) between the intersection areas, a pair of river channels (4o, 42), one of which is connected to each one of the liquid passages is enclosed, and by means of the exterior of the outer gear element, where this is a minimum distance from the housing, subjecting the outer gear member to rotation relative to the housing will be carried, the devices having a single pressurized fluid inlet (46) and diametrically opposite a single liquid outlet (6o) outside the outer gear element βΟ9811 / 022? 16 - have to create a restricted fluid path, a flow in the direction of rotation of the outer gear member towards the liquid outlet and around the Exterior of the outer gear member is present extending, and wherein both the liquid inlet and the Liquid outlet are connected to the flow channels, and wherein the devices valve devices (5o, 51; 65, 66) included to the pressure fluid having flow channel rait the liquid inlet and the other flow channel to connect to the liquid outlet. 5) two-directional hydraulic motor according to claim 4, characterized in that that connecting channels containing the flow channels (4o, 42) pass through the housing between the housing passages, which can be connected to a pressure source and to a drainage container, and that the valve means a pair of pressure sensitive check valves (5o, 51) included on either side of the liquid inlet (46) are arranged in the connecting channels and respond to pressure, so that one of the housing passages Can supply hydraulic fluid and enables bidirectional operation. 6) bidirectional hydraulic motor according to claim 5, characterized in that that the valve means include a second pair of check valves (65, 66) to the liquid outlet (6o) to connect to the housing passage (3o, 31), which is connected to the drainage container. 7) Gerotor type bi-directional hydraulic motor, characterized by: - 17 - 6098 1 1/0227 a housing (1o) having a pair of passages (3o _f 31), an inner gear element (2o) and an outer gear element (21) rotatably mounted in the housing, the outer gear element being eccentric with respect to the inner gear element is, whereby a series of liquid chambers is formed between the gear elements and wherein the teeth of the gear elements interact at two intersection areas at which fluid communication between the liquid chambers on both sides of the intersection areas is blocked, a pair of kidney-shaped liquid passages (41, 43) between the intersection areas, and by means that the exterior of the outer gear member, v / o this has a minimal distance from the housing, a Expose fluid pressure to a radial balance of the outer To obtain gear member at startup and to free the outer gear member for rotation with respect to the housing and balanced during rotation, the means having a single pressurized fluid inlet (46) and a diametrically opposed single fluid outlet (6o) outside the outer gear member contained around a limited fluid path with flow in the direction of rotation of the outer gear member towards the fluid outlet to create a loop around the outside of the external gear from a point in front of your point at which the outer gear element is a minimum distance from the housing to v / e extends to a point beyond this point, and wherein the means include means for the pressurized fluid inlet connect with both housing passages, a flow connection being established only with the housing passage comes, which absorbs hydraulic fluid. 8) bidirectional hydraulic motor according to claim 7, characterized in that that the Ilittel a pair of shut-off valves (5o, 51) - 13 - 60981 1/0227 1 Q I O - contained in the flow path on both sides of the liquid inlet (46) are arranged. 9) Gerotor type bidirectional power transmission device, marked by: a housing (1o) with a cylindrical chamber (12), inner and outer gerotor elements (2o, 21), the inside dar chamber with a free space between the chamber wall and are located on the outer periphery of the outer gerotor element, a pair of housing passages (3o, 31) which can be connected to pressure or a drainage container, Connecting channels in the housing, which connect the housing passages to one another and contain flow channels (4o, 42) to fluid passages (41, 43) which connect the gerotor elements assigned, Means for supplying a flow of liquid to the free space in each of the two working directions, which contain a liquid inlet (46) for free space (45) and generally in line with a line through the axis of rotation of the inner gerotor element and the pivot axis of the outer gerotor element, which also contain a liquid outlet channel (6o) from the free space through the liquid flows therethrough and which is diametrically opposite the liquid inlet, both the liquid inlet and the liquid outlet to the connecting channels are connected, and Means for connecting the liquid inlet to that particular housing passage which aaftakes pressure liquid and the liquid outlet to the other housing passage. 60981 1/0227 Blank page