DE1264958B - Gear pump or motor - Google Patents

Description

Gear pump or motor The invention relates to a gear pump or a gear motor with two gears rotating in a housing and meshing externally with one another, the shaft journals of which are mounted on each side of the gears in a common bearing body, with gaps between the bearing bodies and the corresponding inner walls of the housing in one the area of the gear wheels remote bearing body end face and in a region on the outer surface of each bearing body for sealingly pressing the same against the gear side face and are connected to influence the effective in the radial direction on the bearing body hy- draulic forces with the high pressure chamber.

The ones with their inner end faces on the side surfaces of the gears adjacent bearing bodies are dimensioned so that they have almost the same outer diameter how the gears have and closing on both sides of the gears in the recess of this enveloping housing fit. The bearing bodies should be in the axial direction be easily displaceable so that the forces that press them against the gear side surface and so the working spaces can be sealed axially and remain small.

In a known gear pump of this type, the bearing bodies thereby easily axially displaceable, that acting on them tilting moments through radially acting pressure fields acted upon by the delivery pressure on the circumferential surface of each Bearing body are compensated. In doing so, however, it is to avoid pressure losses necessary, the 'leading to the high delivery pressure pressure fields by proportionately to seal expensive O-rings or the bearing body very precisely in the housing recess to fit in.

It is also known to act on the bearing body in a similar pump an axial pressure with the help of a piston at the front end of the one bearing body and on each of the two bearing bodies a radially relieving force with the aid of one Apply pressure field that is effective on the outer surface of the bearing body. The bearing body must be guided completely tight in the housing. This sets a very high precision in machining and fitting ahead; in uncontrollable Wise penetrating pressure medium can cause high pressure on the outside of the surfaces Generate bearing bodies so that tilting moments and unforeseeable pressure forces arise, which disturb the axial mobility of the bearing body.

It is also known to keep the bearing bodies under low pressure as far as possible on their outside and to provide pressure fields under high pressure only where it is necessary to use forces. Although this leads to pumps that work very well, in which the load on the housing is low and the forces and moments acting on the bearing bodies are as good as balanced, their production is relatively expensive, among other things because the sealing of the various pressure fields is special Requires care. Off nützungserscheinungen at the seals but can lead to a sufficiently high pressure builds up in the pressure more fields and the bearing body does not bear more under all operating conditions on the high pressure side over time. The efficiency could deteriorate.

The invention is based on the object of an opposite principle to pursue, namely to put the bearing body almost completely under high pressure and to keep only a few, precisely measured areas under low pressure.

According to the invention, this object is achieved in that in a gear pump or a gear motor of the type mentioned in a manner known per se Gear wheels with full face width on their orbital path the inner wall of the housing only in a shorter angular range on the low pressure side, on one Touch wall part, sealing (almost) touching and that a delimited inner area the mentioned bearing body end face and a sealed in the axial direction, extending only over part of the axial length of the bearing body to which Subsequent low-pressure chamber, between the shaft journals, on the low-pressure side the lateral surface of the bearing body located area of this lateral surface for Low pressure chamber are relieved, while an axially adjacent to this area, up to the bearing body face extending pressure surface, the axial gap space on a frame-shaped outer Area of the bearing body face and above all the radial gap space on the adjacent the high pressure chamber located part of the lateral surface from the high pressure chamber are under high pressure, so that excess hydraulic forces acting in the radial direction press the bearing body against the inner walls of the housing in the area of the low-pressure side.

As a result, the elastic seals of the pressure chambers are largely replaced by wear-resistant metallic seals, which are created by the fact that the bearing body with certain zones of its outer surface form-fit on the inner wall of the housing is present. Fewer channels are also required in the bearing body than with the known ones Versions because the pressure medium passes through a gap between the housing and the bearing body flows directly into the areas (pressure fields) that are used to press the bearing bodies in serve radial direction or compensate for the tilting moments acting on the bearing body. The bearing body is easier to manufacture. Its external dimensions can be less be more accurate than in the known designs, as there is a different gap height between the inner walls of the housing and the circumferential surface of the bearing body are only insignificant the effective area of the pressure field changes, the size of which determines the pressure the bearing body against the housing inner walls of the low-pressure side is dependent on where the bearing bodies fit tightly.

To make the direction of rotation of a pump or a motor of the type mentioned reversible, according to a further proposal of the invention, the pump (the motor) is designed so that the gears with full tooth width on their orbital path, namely when rotating in both directions of rotation and Funding in one direction or the other, the inner wall of the housing in each case only (almost) touch sealingly in an angular area located on the respective low-pressure side, for which, in addition to the low-pressure chamber and next to the high-pressure chamber, corresponding wall parts are provided for this possibility of contact, and that a delimited inner The area of the bearing body end face remote from the gears and one of two similar areas which are opposite one another between the shaft journals on the outer surface of the bearing body and are open to the bearing body end face facing the gears and thus to the low-pressure or high-pressure chamber, relieved to the low-pressure side et are, while the other of these areas as well as on both sides of the bearing body axially next to the areas, these are sealed against them - and extending to the bearing body outer surface remote from the gears, - also a frame-shaped outer area of this bearing body end face and the rest of the Pressure side from accessible gaps or areas on the bearing body surface from the high pressure chamber are under high pressure, so that excess hydraulic forces acting in the radial direction press the bearing body against the housing inner wall in the area of the respective low pressure side. The advantage of this exemplary embodiment consists in particular in the completely symmetrical construction of the bearing body and housing, which considerably simplifies the manufacture of these parts, even for pumps and motors with two directions of rotation.

Further details and features of the invention are still in the subclaims contain.

In the following, exemplary embodiments of a pump or a motor with the features according to the invention are described and explained in more detail with reference to the drawing. It shows F i g. 1 shows a cross section through a first embodiment along the line I-1 in FIG. 2 with a partial section of a bearing body through the center of a stopper, FIG . 2 shows a longitudinal section along the line 11-11 in FIG. 1, FIG. 3 shows a side view of the suction side of a bearing body of the first embodiment with part of the same in section . F i g. 4 is a front view of a bearing body of the first embodiment, FIG . 5 shows a horizontal cross section through a second embodiment along the line VV in FIG. 6 with a partial section of a bearing body through the center of the stopper, FIG . 6 shows a longitudinal section along the line VI-VI in FIG. 5, Fig. 7 shows a partial section along the line VI-VI in FIG. 5 by a modification of the embodiment according to FIG. 6 with relief valves, F i g. 8 is a side view of the pressure side of a bearing body of a third embodiment, FIG . 9 shows a partial section along the line IX-IX in FIG. 8.

The housing 1 of the liquid displacement machine that can be used as a pump or motor is provided with a low-pressure channel 2 and a high-pressure channel 3 on the same axis opposite one another (FIG. 1). Both channels 2, 3 open into a cavity of the housing 1, which is formed by two recesses 4 and 5 merging into one another in the groove. In these recesses 4 and 5 , two gears 6 and 7 provided on both sides with shaft journals are inserted. The shaft journals are mounted in bores 8 and 9 of spectacle-shaped bearing bodies 10 and 11 , which fit exactly into the recesses 4 and 5 of the housing 1. A shaft journal of the lower gear 7 protrudes from the bearing body 11 and a housing cover closing the housing 1 with a cone and can be coupled to a drive device (not shown). In the cylindrical surfaces of the recesses 4 and 5 surrounding the gears, there are circumferential grooves 12 and 13 which extend from the high-pressure channel 3 to the vicinity of the low-pressure channel 2.

If the gear 7 is in the in F i g. 1 driven by the direction of rotation indicated by an arrow (operation as a pump), the gears 6 and 7 rotate in opposite directions. The pressure medium entering through the low pressure 'channel 2, for. B. oil is conveyed through the tooth chambers 14 into a high pressure chamber 30 , so that the gears are pushed because of the radial play between them and the recesses 4.5 by the pressure prevailing in the high pressure chamber to the low pressure side, so that on the wall parts 15, the so-called "contact wall parts", the inner wall of the housing between the circumferential grooves 12, 13 and the low pressure channel 2, at least one tooth head each glides past in a sealing manner and separates the high and low pressure sides from one another.

With the gear wheels, the correspondingly fitted bearing bodies 10, 11 are also pressed towards the low-pressure side. This creates radial gaps 16 on the high pressure side between the bearing bodies and the housing. There is also play between the two outer bearing body end faces 23 and the end walls of the housing. As a result of this axial play, the bearing bodies can be displaced in the axial direction so that they can be pressed against the side surfaces of the gears 6, 7. The resulting axial gap spaces 17 connect, when there is working pressure in the high pressure chamber 30 , via the radial gap spaces 16 the high pressure chamber with a recess or cutout on the low pressure side of the bearing body, which forms a pressure surface 18 , so that pressure oil from the high pressure chamber to the Bearing body around, to the pressure surface 18 can flow. The entire pressurized area of the bearing bodies 10, 11 is sealed off from the low-pressure side by means of elastic stopping plugs 19 inserted in bores 20 of the bearing bodies and a metallic form fit between the bearing bodies and the housing (FIG . 3). In order to clearly determine the relieved area, relief grooves 21 are milled into the casing surfaces of the bearing bodies in addition to the pressure surfaces 18 , which are connected directly to the low-pressure chamber 30 ' via areas 22 designed as milled recesses or recesses.

Remote on the gears and the outer bearing body end faces 23 are for the delimitation of Axialdruckfeldem endless seals 25 (0-rings) inserted into glasses-shaped grooves 26 (F i g. 4). The inner areas 27 on the bearing body end faces 23, which are enclosed by the seals 25 and also include the two bearing bores 8, 9, are connected to the low-pressure side of the machine by relief bores 28. The axial pressure fields thus arise on the frame-shaped outer regions 24 of the bearing body end faces 23 surrounding the inner regions 27. The outer regions 24 are designed so that the bearing bodies 10, 11 are pressed against the side surfaces of the gears 6, 7 by their axial pressure fields and seal axially there . During operation, hydraulic forces acting on the bearing body end faces create moments that can be compensated for by the corresponding dimensions of the pressure faces 18 and the milled areas 22. The recesses or bores 20 for the blocking plugs are connected by channels 29 to the diagonally opposite high-pressure chamber 30 . The high pressure chamber 30 is located directly in front of the engagement area of the gears 6, 7. It is the starting point for the high pressure channel 3. Directly behind this engagement area is the low pressure chamber 30 ', into which the low pressure channel 2 opens directly.

Pressure pockets 31 for relief and hydrostatic lubrication of the bearing are provided in the bearing bores 8, 9 (FIG. 1). Their position results from the direction of the bearing force. With the present construction - they come to lie in the vicinity of the locking plug 19; they are supplied with pressurized oil from the recess 20 via small bores 32.

In the reversible design of the gear pump or the motor ( FIGS. 5 to 7) , the circumferential grooves 40 are symmetrical to the plane through the two gear axles, so on neither side are milled through to the respective high pressure or low pressure channel 41, 42.

There are namely on both sides of the mentioned plane, so both on the low pressure channel 41 or on the low pressure chamber 30 a and on the high pressure channel 42 or on the high pressure chamber 30 b, which are interchanged with each other when the direction of rotation, two wall parts 15 a, 15 b of the Housing inner wall biw. of the housing bore walls surrounding the gearwheels are provided, on which the gearwheels can almost touch the inner wall of the housing in a sealing manner, the gearwheels around the bearing bodies 43, 44, but only on the respective low-pressure side contact wall parts 15 a or 15 b, these wall parts ( almost) touch. The circumferential grooves 40 are connected to the respective high pressure chamber 30 b or 30 a from the high pressure gaps around the bearing bodies 43, 44 and via the corresponding tooth gaps of the gears.

In contrast to the embodiment according to FIGS. 1 to 4, in which only one pressure surface 18, only one area 22 open to the low pressure side and only one locking plug 19 are provided, are provided on each bearing body in the embodiment according to FIGS . 5 to 7 two pressure surfaces 18 a, 18 b open to the axial gap 17 , two areas 22 a, 22 b, one of which then opens to the low-pressure side and the other to the high-pressure side, and two blocking plugs 19, 19 ' in two bores 20, 20 ' intended. These pressure surfaces, areas and bores are located on the bearing body symmetrically with respect to the plane through the two gear axles. But only the blocking plug 19 or 19 ' located on the respective low-pressure side part of the lateral surface of the bearing body is acted upon by a channel 29 or 29' on its underside with liquid under high pressure, so that it actually has a sealing effect. -In addition, in the execution according to the F i g. 5 to 7 , two pressure pockets 31, 31 'are also provided in each bearing bore of the bearing body 43, 44, especially for the execution as a motor.

The axial gaps 17 on the bearing body end faces 23 remote from the gears and the inner areas 27, which are delimited and sealed against the outer frame-shaped areas 24 by an endless seal 25 , correspond to the relevant parts in the embodiment according to FIGS. 1 to 4. But the relief channels 28 to the inner end face areas 27 are missing in the embodiment according to FIGS. 5 and 6. In this embodiment, the two inner areas 27 to be relieved are connected to the outer bearing body end faces 23 through a longitudinal bore 45 in one of the gearwheel shafts and connected to a leakage oil line 46 so that they are filled with Leek oil. In the modification according to FIG. 7 is performed per 48 for high-pressure and low-pressure channel 41, 42 is a drain line. A relief valve 47 is arranged in each of these leakage oil lines 48. One of these valves relieves the pressure on the respective low-pressure channel.

For cases in which particularly narrow bearing bodies are desired, the bearing body design according to FIGS . 8 and 9 thought. On the pressure-side part of the bearing body 10 a, an O-ring 51, which lies in a groove 52 of the bearing body which is connected to the high-pressure chamber 30 via the small bore 53 , is an area that is remote from the gears and more towards the outer bearing body face 54, which is relieved through the bore 55 towards the low-pressure chamber and can be referred to as "additional relief area". This shifts the point of application of the resultant of the hydraulic force on the high pressure side in the direction of the gears, so that the torque counteracting the tilting moment increases. Tilting moments can thus be compensated for even with narrow, spectacle-shaped bearing bodies.

Claims (2)

Claims: 1. Gear pump or motor with two gears rotating in a housing and meshing externally with one another, the shaft journals of which are mounted on each side of the gears in a common bearing body, with gaps between the bearing bodies and the corresponding inner walls of the housing in a region of the gears remote bearing body face and in an area on the outer surface of each bearing body for sealingly pressing it against the gear wheel side surfaces and for influencing the hydraulic forces acting in the radial direction on the bearing body are connected to the high pressure chamber, characterized in that the gear wheels (6, 7) with -full tooth width on its circumferential path the inner wall of the housing only in a shorter angular range located on the lowering side, on a contact wall part (15), sealingly (almost) touching and that a delimited inner area (27) of the mentioned bearing bodyst in the area (23) and an area sealed in the axial direction, extending only over part of the axial length of the bearing body (10, 11) , adjoining the low-pressure chamber (30 ') and located between the shaft journals on the low-pressure side of the outer surface of the bearing body ( 22) of this lateral surface to the low-pressure chamber (3W) are relieved, while a pressure surface (18) axially adjacent to this area (22) and extending to the bearing body end face (23 ), the axial gap space (17) on a frame-shaped outer area (24) of the bearing body end face (23) and above all the radial gap space (16) on the part of the lateral surface located next to the high pressure chamber (30) are under high pressure from the high pressure chamber, so that excess hydraulic forces acting in the radial direction affect the bearing body (10 or 11) press against the inner wall of the housing in the area of the low-pressure side. 2. Pump or motor according to claim 1, characterized in that, in a manner known per se, the inner region (27) connected to the low-pressure side on the bearing body end face (23) remote from the gears includes the bearing bores for the shaft journals and is provided with an endless seal ( 25) and is sealed against the frame-shaped outer area (24) of this end face. 3. Pump or motor according to claim 1 or 2, characterized in that the located on the low pressure side and relieved to the low pressure chamber area (22) on the outer surface of each bearing body (10, 11) in the axial direction by an elastic, by liquid under high pressure the blocking plug (19) pressed against the corresponding wall part of the inner wall of the housing is sealed against the high pressure gap chamber on the pressure surface (18) extending towards the end face of the bearing body. 4. Pump or motor according to claim 3, characterized in that the low-pressure chamber relieved area (22) and the bearing body end face (23) facing, high pressure pressure surface (18) on the low-pressure side part of the bearing body (10, 11) of flat Recesses of the same are formed, which are axially one behind the other on both sides of the locking plug (19) , and that this locking plug (19) is inserted into a corresponding recess or bore (20 ') of the bearing body connected to the high-pressure chamber of the machine by a channel (29) . 5. Pump or motor according to claim 1, characterized in that the located on the low pressure side, with the full tooth width of the teeth of the gears (6, 7) sealingly (almost) touched contact wall parts (15) of the housing inner wall. each extend directly next to the low-pressure chamber (30 ') over an angular area slightly projecting a tooth pitch, the remaining housing wall parts around the gearwheels each being provided with a circumferential groove (12, 13) and thus with the high-pressure chamber (30). stay in contact. 6. Pump or motor according to one of claims 1 to 5, characterized in that on the part of the lateral surface of each axially displaceable bearing body (z. B. 10a) located next to the high pressure cylinder, an additional relief area (54) remote from the gears is delimited and is connected to the opposite low-pressure side. 7. Gear pump or motor with two gears rotating in a housing and meshing with one another in external engagement, the shaft journals of which are mounted on each side of the gears in a common bearing body, with gaps between the bearing bodies and the corresponding inner walls of the housing in a region of the bearing body end faces remote from the gears and in an area on the lateral surface of each bearing body for sealingly pressing the same against the gear wheel side surfaces and for influencing the hydraulic forces acting in the radial direction on the bearing body with the high pressure chamber, characterized in that the gear wheels with full tooth width on their orbital path, namely at Circulation in both directions of rotation and conveying in one or the other direction, the inner wall of the housing only touching (almost) sealingly in an angular area on the respective low-pressure side, including next to the low-pressure chamber and next to the high-pressure chamber (30a, 30b) corresponding wall parts (15 a, 15 b) are provided for this possibility of contact, and that a delimited inner area (27) of the bearing body end face (23) remote from the gears and one of two similar areas (22 a, 22 b) , which each lie opposite one another between the shaft journals on the outer surface of the bearing body (43, 44) and are open to the bearing body end face facing the gears and thus to the low-pressure or high-pressure chamber, are relieved to the low-pressure side, while the other of these areas (22a or 22b) and on both sides of the bearing body (43, 44) in each case axially next to the areas (22a, 22 b) located, these opposite sealed and up to the gear wheels remote bearing body end face (23), check-extending pressure surfaces (18a, 18b), further a frame-shaped outer area (24) of this bearing body end face and remaining gaps or areas on the bearing body accessible from the pressure side shell surface are under high pressure from the high pressure chamber, so that excess hydraulic forces acting in the radial direction press the bearing body against the inner wall of the housing in the area of the respective low pressure side. 8. Pump or motor according to claim 7, characterized in that in a known manner the inner region (27) connected to the respective low-pressure side on the end face (23) of each bearing body (43, 44) remote from the gears, the bearing bores for the motor shafts includes, bounded by an endless seal (25) and sealed against the frame-shaped outer region (17) of this end face. 9. Pump or motor according to claim 7 or 8, characterized in that the area located on the respective low-pressure side (22 a or 22 b) on the outer surface of each bearing body (43, 44) by the housing (1) adjacent zones of the bearing body and in the axial direction by means of an elastic seal (19, 19 ') pressed by liquid under high pressure against the corresponding wall part of the inner walls of the housing against the pressure surface (18 a or 18 b) which is under high pressure and is open towards the bearing body end surface (23) remote from the gears is sealed. 10. Pump or motor according to claim 9, characterized in that the areas (22 a or 22 b) and the pressure surfaces (18 a, 18 b) of flat recesses of the bearing body (43, 44) are formed axially one behind the other on both sides of the than Plug formed seal (19, 19 ') are, and that each of these seals is inserted into a, corresponding recess or bore (20, 20') of the bearing body, which through channels (29, 29) in the bearing body each with the high pressure chamber or Low pressure chamber (30a, 30b) are connected to the opposite side. 11. Pump or motor according to claim 7, characterized in that the wall parts (15a, 15b), which of the gears (6, 7) with the full tooth width (almost) can be contacted in a sealing manner, each immediately next to the low-pressure and the high pressure chamber (30a or 30b) extend over an angular range slightly projecting a tooth pitch, and that between these wall parts (15 a, 15 b) circumferential grooves (40) are provided in the housing inner wall, these circumferential grooves (40) due to the radial play between each Bearing body (43, 44) and the inner wall of the housing, depending on the direction of rotation, are connected to the respective high-pressure chamber. 12. Pump or motor according to one of claims 1 to 11, characterized in that in each bearing bore (8, 9) at least one lubrication pocket (31) is provided which is connected to a high pressure area of the bearing body. Documents considered: German Auslegeschrift No. 1 006 722; Austrian Patent No. 207 254; British Patent No. 782,701; USA. Patent Nos. 2,728,301, 2,871,794.