DE8714166U1 - Device for supplying oil or similar lubricant from a housing of a gear transmission containing an oil sump - Google Patents

Description

Device for supplying oil or similar lubricant from a housing of a gear transmission containing an oil sump

The invention relates to a device for supplying oil or similar lubricant from a housing of a gear transmission containing an oil sump to at least one component annularly surrounding a shaft set in rotation by the transmission, such as a shaft seal or a shaft bearing, by utilizing the counter-rotating orbital movement of two gears meshing with one another.

A device of this type has already become known, which is used in a Roots blower as a supercharger for a motor vehicle engine. The two rotary pistons of the Roots blower are attached to shafts arranged vertically one above the other, one of which is suitably driven as a drive shaft, while the other shaft is rotated synchronously with the drive shaft by two meshing gears at the shaft ends within the housing containing the oil sump. Since in the known arrangement the oil is only introduced into the gearbox housing in an amount corresponding to about a quarter of the volume of the gearbox, only part of the gear attached to the lower shaft is immersed in the oil sump during operation. The oil is shoveled to its upper apex by this lower gear, whereupon the upper gear takes over the conveying work in the same way and the oil demanded by the lower gear is in turn

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its circulation to the area of its upper apex. From here, part of the oil then reaches an upper %n lubricating bearing and sealing area. To achieve oil conveyance in this way, the gear housing is provided with guide devices facing the front sides of the gears, which ensure that the oil is clearly guided and are intended to prevent the oil conveyed upwards by the meshing gears from splashing in lateral directions.

With the help of the known oil supply device, it is possible to lubricate and/or cool components close to the transmission, such as shaft seals and shaft bearings, due to the oil carried along by the immersion of the lower gear in the turbulent oil sump. However, the splash oil pumped up in this way cannot be transported to bearing or sealing points far from the transmission, such as those provided at the shaft ends opposite the gear transmission, as it is not under pressure. In order to ensure sufficient lubrication and cooling of the shaft bearings and seals, forced lubricant circulation is generally required, in order to avoid overheating of the sealing elements, for example the O-rings in connection with mechanical seals. Such forced circulation is usually achieved by means of an oil pump, which, for example, takes oil from the oil sump of the transmission housing and supplies it to the components of the respective shaft that are to be cooled and/or lubricated. The heated oil then flows back into the gearbox housing via a return line. Such forced oil circulation is associated with a high level of construction effort, as it requires a separate oil pump with drive, which has a negative impact on the production and operating costs of the respective machine. This can involve a wide variety of types of machines, such as machine tools, the Roots blowers mentioned at the beginning, or rotary piston pumps for pumping liquids such as liquid manure.

The invention is therefore based on the object of creating an oil supply device of the type specified at the outset, with whose

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With the help of this, cooling and/or lubrication of components surrounding a shaft in a ring in areas remote from the gearbox can be achieved by forced circulation without the need for a separate oil pump with an associated drive.

This object is achieved according to the invention in that the two meshing gears in the area of one of the two gussets formed on both sides of their tooth engagement gap are assigned an encapsulation element that encapsulates this and is flooded with oil during operation. Through this, the two gears are designed in the manner of a gear pump in an area that includes the encapsulated gusset and the adjacent tooth engagement gap up to the zone of the plane of symmetry of the two gears, and that the encapsulation element is provided with a removal channel for oil pumped into the encapsulated gusset by the two gears.

In this way, the two gears meshing with each other in the gearbox housing, e.g. the synchronous gears of a rotary piston pump, themselves and additionally take on the function of an oil pump, with the help of which an oil circuit can be maintained that includes components of the shaft that are remote from the gearbox, such as seals and bearings. When the two meshing gears rotate in directions of rotation that converge towards the encapsulated gusset, the oil that is pumped into the encapsulated gusset in the manner of a gear pump is taken over on the pressure side by the extraction channel of the encapsulation device and fed at a pressure of about 1 bar via an oil line connected to the channel to the components that are remote from the gearbox, such as the bearing and sealing units arranged at the opposite end of the line, in order to be fed back into the oil sump of the gearbox housing after flowing through them via a suitable return line. This Forced lubricant circulation without a separate oil pump and external drive ■--.«! can also be set up when the direction of rotation of the two meshing gears is reversed, i.e. when they rotate in the direction of rotation away from the encapsulated gusset, since under these conditions negative pressures of up to about 0.9 bar are created in the encapsulated gusset. This allows oil to be pumped out of the encapsulated gusset with the help of the rotating gears.

the respective oil chamber of the component of the shaft to be cooled and/or lubricated, for example a mechanical seal on the upper shaft, whereby due to the fact that oil flows from the gear housing via the sump-side connecting line into the component to be cooled and/or lubricated, e.g. the mechanical seal on the lower shaft and then via an internal connecting channel into the upper ring component, a closed oil circuit is again achieved in this mode of operation.

Numerous other features and advantages of the invention emerge from the claims and the following description in conjunction with the drawing, in which several embodiments of the subject matter of the invention are illustrated. In the drawing:

Fig. 1 is a partially vertically sectioned side view of a rotary piston pump with an oil supply device according to the invention,

Fig. 2 is a section along the line II-II of Fig. 1, Fig. 3 is a section along the line III-III of Fig. 2, Fig. 4 is a representation of the device according to Fig.

1 to 3 used encapsulation element in a sectional view according to Fig. 2 or

the line IV-IV of Fig. 5,
Fig. 5 is a plan view of the encapsulation member according to Fig.

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Fig. 6 is a side view of the encapsulation element according to Fig. 5, Fig. 7 is a vertical section through the spindle bearing of a machine tool to illustrate a further embodiment of the oil supply device according to the invention,

Fig. 8 shows a section along the line VII-VIII of Fig. 7 and Fig. 9 shows a further embodiment of an oil supply device according to the invention in a sectional view corresponding to Fig. 8.

In Figs. 1 to 3, a rotary piston pump is shown with a pump chamber 1 in which a pair of rotary pistons 2 and 3

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in the manner of Roots rotors in opposite directions with a phase difference of 90° by means of two vertically arranged shafts 4 and 5, on which the rotary pistons 2 and 3 are each fixed for one revolution with the shafts 4 and 5. The shaft 4 is connected to an external drive means at its shaft end 6 on the right-hand side of Fig. 1 in a manner not shown in detail and is driven, for example, in the direction of rotation shown by the arrow 7. The upper shaft 4 in the example shown is thus the drive shaft, while the lower shaft 5 is rotated synchronously with the drive shaft 4 by two meshing gears 8 and 9 of a synchronous gear 10.

The pump chamber 1 is formed in a central housing part 11, which supports a roller bearing 13 for the rotatable mounting of the drive shaft 4 and a shaft seal 14 in the form of a mechanical seal in a housing part 12 of reduced diameter adjacent to the synchronous gear 10. A further roller bearing 15 and a further shaft seal 16, also in the form of a mechanical seal, are supported in the end region of the drive shaft 4 adjacent to the shaft end 6 for the rotatable mounting and sealing by a housing cover 17 which is flanged to the housing 11. In a corresponding manner, a rolling bearing 13 and a shaft seal 14 opposite to those of the shaft 4 and a rolling bearing 15 and a shaft seal 16 opposite to those of the shaft 4 are supported on the lower shaft 5 by means of the housing part 12 and the housing cover 17, these being provided with central support parts 18 and 19. The rolling bearing 15 and the shaft seal 16 of the lower shaft 5 are made visible in Fig. 1 and are designated 15* and ^16f respectively.

A housing cover 20 is also flanged to the housing part 12, which forms with the latter a gear housing 21 containing an oil sump in its lower area, in which the synchronous gear 10 is housed. The oil level in the gear housing 21 is so high that not only the lower gear 9, but also the upper gear 8, approximately up to the height of the shaft 4, are immersed in the oil sump when the synchronous gear rotates.

The turbulent oil circulation generated in this way within the gear housing 21 simultaneously cools and lubricates the rolling bearing 13 and the shaft seal 14 due to the connection along the shaft 4, due to their arrangement close to the gear unit, by spraying or throwing off oil.

Uli. In order to also achieve lubrication and cooling of the roller bearings 15, 15' and the shaft seals 16, 16' in the area of the shaft ends facing away from the synchronous gear 10, the synchronous gear 10 is designed in the manner of a gear pump in the area of the tooth engagement gap 22 of its meshing gears 8 and 9. For this purpose, an encapsulation element 25 is arranged in one of the two gussets 23 and 24 formed on both sides of the engagement gap 22 between the gears 8 and 9, in the example shown the gusset 24, which is provided with a removal channel 26 for oil conveyed into the encapsulated gusset 24 by the two gears 8 and 9.

The encapsulation element 25 is formed by a body preferably made of plastic or a sliding metal, which, as can be seen in particular from the individual representations according to Figs. 4 to 6, has a U-shaped basic configuration in plan view with an inner base part 27, an outer base part 28 and two outer side legs 29. The inner base part 27 is divided into a central web part 30, which comprises an opening 31 of the removal channel 26 opposite the engagement gap 22 between the gear wheels 8 and 9, and two arcuate areas 32.

The arcuate areas 32 adjoin the web part 30 on both sides and follow the tip circle 33 of the two gears 8 and 9, which is indicated in Fig. 4 with its radius R. H denotes the vertical center distance between the two gears 8 and 9, whereby the center distance also defines the plane of symmetry 34 of the two gears 0 and 9, shown in dash-dot lines. The arcuate areas 32 are each closely adapted to the tip circle 33 and the two side legs 29 with their inner sides are each closely adapted to the outer side of the two gears 8/9, so that

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the rotation of the gears 8, 9 is not impaired, but on the other hand oil leakage to the outside between the mentioned areas or surfaces of the encapsulation element 25 and the gears 8, 9 is prevented.

The middle web part 30 connects the two curved areas 32 of the inner base part 27 in such a way that its outer surface bridges the distance between the tip circles 33 of the two gears 8, 9. The diameter of the opening 31 of the removal channel 26 is essentially the same as the width or, based on the arrangement of the gears 8, 9 vertically one above the other, the height of the outer surface of the web part 30.

By appropriately dimensioning the dimension C (Fig. 4) of the encapsulation element 25, the arc length of the two arcuate areas 32 of the inner base part 27 is dimensioned such that in all operating positions of the gears 8, 9 at least one tooth tip of each gear 8, 9 is overlapped by the arcuate areas 32. This ensures that during the rotation of the gears 8, 9, in no gear position does a free flow connection occur between the discharge opening 31 and the outside of the encapsulation element 25.

In the present embodiment, the extraction channel 26 comprises an oil receiving bore 35 opening out at the mouth opening 31 in the encapsulated gusset 24 and a connecting bore 36 connected to it at right angles, the diameter d of which is at least equal to the diameter of the receiving bore 35. The outlet of the extraction channel 26 with the connecting bore 36 is provided in the outer base part 28, which also serves to fasten the encapsulation element 25 with the aid of screw connections 37 to a flange part 38, through which the connecting bore 36 of the extraction channel 26 is extended with a connecting sleeve 39 for connecting an oil delivery line 40.

The encapsulation of the gusset 24 is perfected by the fact that the side legs 29 of the encapsulation element 25 extend from the encapsulated gusset 24 at least up to the plane of symmetry

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34 of the two gears B, 9, whereby they exceed the symmetry plane 34 by a maximum of the dimension A of a pitch length of the gears 8* 9. The width B of the encapsulation element 25 is dimensioned such that the side legs 29, taking into account the dimension b determined by the axial gear thickness, have sufficient stability on the iron between the inner surfaces of the side legs 29 in relation to the pressure arising in the hollow side of the encapsulation element 25.

In this way, in the area of the encapsulated gusset 24, a section of a gear pump is formed, so to speak, so that when the drive shaft 4 is assumed to rotate in accordance with arrow 7, which is equivalent to a direction of rotation of the gears 8 and 9 in the direction of arrows 7a, oil is pumped in the manner known for gear pumps through the meshing gears 8 and 9 on the outside in the tooth gaps along the curved areas 32 into the gear area in front of the mouth opening 31 of the extraction channel 26. On the pressure side of the pump device thus created, the oil is removed at a pressure of approximately 1 bar and is pumped through the oil delivery line 40 via a connecting bore.

41 in the housing cover 17 to the oil chamber 42 between the roller bearing 15 and the shaft seal 16 at the end of the drive shaft 4 remote from the gearbox in order to cool and lubricate these components. From there, the oil flows through a further connecting hole 43 in the cover part 19 into the oil chamber

42 of the roller bearing 15' and the shaft seal 16' at the end of the lower shaft 5 remote from the gearbox, in order to finally be fed back into the oil sump of the gearbox housing 21 via a line 44 connected to the lower area of this oil chamber 42* This circuit is symbolized in Fig. 1 by the solid arrows 45.

When the direction of rotation of the drive shaft 4 is reversed according to arrow 46 (Fig. 1), the direction of rotation of the gears 8, 9 is also reversed correspondingly against the movement arrows 7a shown in Fig. 2. This is accompanied by a reversal of the delivery direction of the oil pump formed by the encapsulation element 25, whereby in the encapsulated gusset

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24 Negative pressures of up to 0.9 bar are created. Due to the existing pin flow connection, oil is sucked in from the oil chamber 42 in the area of the roller bearing 15 and the shaft seal 16 of the drive shaft 4 via the line 40. As a result of the fact that oil from the oil sump of the gear box 21 flows via the connecting line 44 opening out of its lower end area into the oil chamber 42 of the roller bearing 15' and the shaft seal 16' of the lower shaft 5 and from there via the connecting bore 43 into the oil chamber 42 of the roller bearing 15 and the shaft seal 16 of the upper drive shaft 4, the oil circuit is closed again. This circuit is symbolized in Fig. 1 by ^the flow arrows 47 shown in dashed lines.

Although the area-wise design of the meshing gears 8 and 9 with the aid of the encapsulation element 25 as an oil pump was explained above in the context of the preferred application within a rotary piston pump, in particular with rotary pistons designed as Roots rotors for conveying inhomogeneous liquids, such as liquid manure, it is understood that in principle a rotary piston design with the aid of the encapsulation element 25 can also be used in other machines with gear drives running in an oil sump.

For this purpose, reference is first made to the embodiment according to Figs. 7 and 8, in which the bearing of the shaft or spindle 48 of a machine tool is illustrated with roller bearings 49 and 50. Due to high speeds with high bearing loads, oil cooling of the roller bearings 49, 50 in the two end areas of the spindle 48 is necessary. In the embodiment according to Figs. 7 and 8, this is done with the help of two meshing gears 51 and 52, of which the gear 51 is attached to the driven spindle 48 and the gear 52 is attached to a shaft 53 for rotation with the latter. The encapsulation element 25 has the arrangement shown in Fig. 8 for encapsulating the gusset 24. The removal channel 26 in this example is formed by only a single bore opening out in the gusset 24, which at the other end is led through a connecting sleeve 54 through a housing wall 55 of the machine tool, to which the encapsulation element 25 is also attached. A conveying line is connected to the connecting sleeve 54.

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56 connected^ with which the pressure oil taken from the gusset 24 in the manner already described is fed directly to the rolling elements of the bearings 49 and 50 via connecting holes 57 and 58 in the two bearing housings 59 and 60. The oil, heated after passing through the bearings, reaches the oil sump formed within the bearing arrangement via return holes 61 and 62 in the bearing housings 59 and 60, into which the two meshing gears 51 and 52 are immersed and whose liquid level is at least high enough that the encapsulation element 25 is flooded with oil during operation.

While in the embodiment according to Figs. 1 to 6 the two meshing gears 8 and 9 are of the same size, the embodiment according to Figs. 7 and 8 illustrates the arrangement and design of the encapsulation element 25 in connection with two meshing gears of different sizes. A significant difference to be noted here is that the two arcuate areas 32 of the encapsulation element 25 have a different arc length to adapt to the different diameters of the two gears 51 and 52 and that the side legs 29 intersect the symmetrical drive plane 34 of the gears 51, 52 at an angle due to the lowered gear 52, and in the area of the engagement gap 22 the plane of symmetry 34 is again exceeded by a maximum of one pitch length. Otherwise, there is agreement with the embodiment according to Figs. 1 to 6, particularly with regard to the mode of operation.

If there is no gear pair running in an oil bath or immersed in it at least in the area of its engagement gap, but only a single gear, such as the gear 63 according to Fig. 9, is immersed in an oil sump, while the other gear 64 is arranged above the liquid level, the principle of oil extraction by means of the encapsulation element 25 can still be implemented in that, as illustrated by the embodiment according to Fig. 9, the encapsulation element 25 itself is provided with a free-running auxiliary

j gear 65 which meshes with gear 63 like gear 64, but unlike gear 64 is located below the

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The auxiliary gear 65 is mounted so that it can rotate freely on an axle 67 in a projection 66 of the side legs 29. Otherwise, the arrangement corresponds to the embodiment described with reference to Fig. 8, as is indicated by the use of the same reference numerals for the same or corresponding components.

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Claims (10)

Expectations: 1. Device for supplying oil or similar lubricant from a housing of a gear transmission containing an oil sump to at least one component, such as a shaft seal or a shaft bearing, which surrounds a shaft set in rotation by the transmission in a ring shape, by utilizing the counter-rotating movement of two gear wheels meshing with one another, characterized in that the two meshing gear wheels (8,9; 51, 52; 63, 65) are assigned an encapsulating element (25) in the region of one of the two gussets (24) formed on both sides of their meshing gap (22) which encapsulates the latter and is flooded with oil during operation, by means of which the two gear wheels (8,9; 51, 52; 63, 65) are designed in the manner of a gear pump in an area enclosing the encapsulated gusset (24) and the adjacent meshing gap (22) up to the zone of the plane of symmetry (34) of the two gear wheels. and that the encapsulation member (25) is provided with a removal channel (26) for oil conveyed into the encapsulated gusset (24) by the two gear wheels (8 _f 9;51,52;63,65). 2. Device according to claim 1, characterized in that the encapsulation member (25) has a U-shaped basic configuration in plan view with an inner base part (27) and two outer side legs (29) and that the inner base part (27) into a central web part (30) comprising an opening (31) of the extraction channel (26) and two adjacent web parts (30) on both sides, each following the tip circles (33) of the two gear wheels (8,9;51,52;63,65) and closely spaced from them. H Monthly * * #1 « *·4 adapted arcuate areas (32), while the two side legs (29) are closely adapted with their inner sides to the outer sides of the two gears. 3. Device according to claim 2, characterized in that the central web part (30) has an outer surface which is perpendicular to the longitudinal axis of the removal channel (26) and contains the outlet opening (31) thereof, the width of which is substantially equal to the diameter of the outlet opening (31). 4. Device according to claim 3, characterized in that the width of the outer surface of the central web part (30) essentially bridges the distance between the tip circles (33) of the two gear wheels (8,9;51,52;63&ldquor;65). 5. Device according to one of claims 2 to 4, characterized in that the length of the two arcuate regions (32) of the inner base part (27) is dimensioned such that in all operating positions of the gears (8,9; 51,52; 63,65) at least one tooth head of each gear is overlapped by the arcuate regions. 6. Device according to one of claims 1 to 5, characterized in that the removal channel (26) is formed by a -^ V/ickel (24) and a connecting bore (36) connected to this at an angle and having at least the same diameter for connection to an oil delivery line (40). 7. Device according to one of claims 2 to 6, characterized in that the outer base part (28) of the encapsulation member (25) opposite the inner base part (27) is designed as a fastening area which also contains the outlet of the extraction channel (26). 8* Device according to one of claims 2 ^l 5 to 7, characterized in that the side legs (29) of the encapsulation tit. ft ·&idigr; es ·* * - 3 organo (25) extend from the encapsulated yoke (24) at least to the plane of symmetry (34) of the two gears (8,9;51,52;63,65), but exceed this by no more than the amount of a pitch length of the gears. 9. Device according to one of claims 1 to 8, characterized in that one (65) of the two gears (63,6S) is driven by a free-running auxiliary gear attached to the encapsulation member (25). vt&si /v/vVvj 1 >3&lgr;4- 4 Mi- ^s«v_ ^m. Ji*^,~ a~± i &iacgr;_~.1 1 1 j Ofv &igr; -b -»J fee« ^aujsiuac tacf uua XU UClI DCX CCIISCIICimCXII \ ZSZ> J UBEi ÜJ.II«» encapsulation element (25) is freely rotatable. 10. Device according to one of claims 2 to 9, characterized in that the two arcuate regions (32) of the inner base part (27) are adapted in their length to the possibly different diameter of the two meshing gears (51, 52; 63, 65).