DEVICE FOR COVERING A TOOTH PROFILE

Abstract

A device for covering a tooth profile during machined processing with a tool, including an appliance for applying cooling lubricant to at least one contact area between the tool and the tooth profile during machine processing of the tooth profile by means of the tool. The appliance includes a guiding means by means of which a front face of the tooth profile in an area that is facing towards the contact area and an environment of the tooth profile in front of the area can be at least partially covered. The appliance is formed with at least one conduit which, in the operational state of the guiding means in which the tooth profile is covered, is arranged so as to extend in front of the tooth profile in the area that is shielded by the guiding means, and via which cooling lubricant can be supplied to the contact area through the guiding means.

Claims

1. A device for covering a tooth profile during machine-processing with a tool, comprising an appliance for applying cooling lubricant to at least one contact area between the tool and the tooth profile during machined processing of the tooth profile by means of the tool, wherein the appliance has a guiding means with which a front face of the tooth profile in an area that is facing towards the contact area and an environment of the tooth profile in front of the area can be covered at least partially, wherein the appliance is embodied with at least one conduit, whichin the operative state of the guiding means in which it covers the tooth profileis arranged in the area that is shielded by the guiding means so as to extend in front of the tooth profile, and via which cooling lubricant can be supplied to the contact area through the guiding means.

2. The device according to claim 1, wherein, in its operative state in which it covers the tooth profile, the guiding means delimits at least one channel that is open towards the tool and that can be arranged so as to be at least partially aligned with a tooth intermediate space of the tooth profile.

3. The device according to claim 2, wherein, in the operative state of the guiding means in which it covers the tooth profile, the at least one conduit opens into the channel in an area of the channel that is facing towards the front face of the tooth profile.

4. The device according to claim 1, wherein, in an abutment area at the front face of the tooth profile, the guiding means has a shape that is at least approximately adjusted to the shape of the tooth profile.

5. The device according to claim 2, wherein the lateral walls of the guiding means that delimit the channel respectively have a profile in which the channel width is increased with growing distance from the front face of the tooth profile.

6. The device according to claim 5, wherein, in the abutment area at the front face of the tooth profile, the lateral walls of the guiding means have a height that corresponds to the tooth height between a tooth base and a tooth tip of the tooth profile, wherein the height of the lateral walls of the guiding means respectively decreases with increasing distance from the abutment area at the front face of the tooth profile at least in certain areas.

7. The device according to claim 2, wherein the orifice area of the conduit opening into the channel is embodied in such a manner that, in the operative state of the guiding means in which it covers the tooth profile, the cooling lubricant discharged from the conduit can be guided in the direction of the contact area between the tool and the tooth profile.

8. The device according to claim 2, wherein the appliance has at least two conduits, wherein respectively one orifice area of a conduit is provided in the area of one of the lateral surfaces of the guiding means that delimit the channel that can be assigned to the tooth intermediate space.

9. The device according to claim 8, wherein the conduits are connected to a common cooling lubricant supply area.

10. The device according to claim 1, wherein the direction in which the cooling lubricant can be guided from the conduit in the direction of the contact area between the tool and the tooth profile and a rotational direction of the tool in the contact area with the tooth profile correspond to each other.

11. The device according to claim 2, wherein the appliance has multiple guiding means, wherein respectively one guiding means can be assigned to respectively two teeth and a tooth intermediate space of the tooth profile that is delimited by them.

12. The device according to claim 9, wherein the appliance has a structural component that is connected to the guiding means and that can be brought into operative connection with a work piece holder, with the cooling lubricant supply area being provided in its area.

13. The device according to claim 1, wherein the appliance has a structural component that is connected to the guiding means and that is connected in a movable manner to the further structural component, which in turn can be brought in operative connection with a tool holder.

14. The device according to claim 13, wherein the cooling lubricant supply area comprises cooling lubricant conducting areas in the structural component as well as in the further structural component, wherein an interface between the structural component and the further structural component is sealed off against an environment by means of a seal.

15. The device according to claim 9, wherein the cooling lubricant supply area is embodied in such a manner that cooling lubricant from the cooling lubricant supply area can respectively only be supplied to that conduit that has an orifice area via which cooling lubricant can be applied to a contact area between the tooth profile and the tool.

Description

[0046] Further advantages and advantageous embodiments of the device according to the invention follow from the patent claims and from the exemplary embodiment that is described in principle in the following by referring to the drawing.

[0047] Herein:

[0048] FIG. 1 shows a simplified sectional view of an aircraft engine with a fan and with a low-pressure turbine, wherein the fan is connected to a low-pressure turbine via a gear;

[0049] FIG. 2 shows a longitudinal section view of a gear wheel and a grinding tool, wherein a device for covering the tooth profile of the gear wheel during the grinding process of the tooth profile with the grinding tool is arranged at a front face of the gear wheel; and

[0050] FIG. 3 shows an enlarged three-dimensional partial view of the device for covering according to FIG. 2.

[0051] FIG. 1 shows a turbomachine that is embodied as an aircraft engine 1 of an aircraft with a gear 5 that is embodied as a planetary gear. The aircraft engine 1 is a turbomachine with which the gear 5 can be advantageously combined. As will be clearly shown in the following, the gear 5 can also be used in differently embodied turbomachines, such as a propeller-type turbine air jet engine or a turboprop.

[0052] The aircraft engine 1 has a main rotational axis 2. Further, in the axial flow direction A, the aircraft engine 1 comprises an air intake 3, a fan 4, the gear 5, a low-pressure compressor 6, a high-pressure compressor 7, a combustion device 8, a high-pressure turbine 9, a low-pressure turbine 10 and an exhaust nozzle 11. An engine nacelle 12 surrounds the aircraft engine 1 and delimits the air intake 3.

[0053] The aircraft engine 1 operates in a conventional manner, wherein air entering the intake 3 is accelerated by the fan 4 to create two air flows. A first air flow flows into the intermediate-pressure compressor 6 and a second air flow is passed through a subsidiary flow channel 13 or bypass channel to provide a drive thrust. The intermediate-pressure compressor 6 compresses the air flow that is supplied to it, before the air is further compressed in the area of the high-pressure compressor 7.

[0054] The compressed air that is discharged from the high-pressure compressor 7 is introduced into the combustion appliance 8, where an intermixing with fuel occurs, and the fuel-air mixture is combusted. The resulting hot combustion products expand and in doing so drive the high-pressure turbine 9 and the low-pressure turbine 10 before they are discharged via the discharge nozzle 11 to provide additional drive thrust. The high-pressure turbine 9 and the low-pressure turbine 10 drive the high-pressure compressor 7 or the intermediate-pressure compressor 6 by means of a high-pressure shaft 14 or a low-pressure shaft 15. The low-pressure shaft 15 that couples the low-pressure turbine 10 with the intermediate-pressure compressor 6 is coupled to the fan 4 via gear 5 which represents a reduction gear. A drive torque that is applied via the low-pressure shaft 15 to the gear 5 is increased according to the stationary gear ratio of the gear 5 and is supplied to a fan shaft 16. If the fan 4 is driven by the low-pressure turbine 10, the rotational speed of the low-pressure shaft 15 is reduced according to the gear ratio of the gear 5 and the fan shaft 16 as well as the fan 4 are driven with this reduced rotational speed and with a torque that is increased as compared to the torque that is applied to the low-pressure shaft 15.

[0055] In the embodiment of the gear 5 shown in FIG. 1, a sun wheel of the gear 5 is connected in a torque-proof manner to the low-pressure shaft 15 and a planetary carrier of the gear 5 is connected in a torque-proof manner to the fan shaft 16. A hollow wheel of the gear 5 is fixedly attached at the housing. What is thus present is a so-called epicyclic embodiment of the gear 5. Independently of that, the gear 5 can also comprise other embodiments of a planetary gear.

[0056] In the following, an embodiment of a device 19 for covering a tooth profile 20 of a double helical spur gear or gear wheel 21, which is a planetary wheel of the gear 5, as it is shown in more detail in FIG. 2 and FIG. 3, is described in more detail based on a grinding process with a grinding tool 22 that is embodied as a grinding disc.

[0057] Independently of that, the device 19 can be used in other machined processing procedures, such as milling, punching, broaching, or the like to the extent as it is described below in order to introduce cooling lubricant into a processing gap between the tool that is respectively used for processing a gear wheel and the currently processed surface of the work piece, namely to such an extent that the known disadvantages due to inadmissibly high local structural component temperatures as they are caused by processing are avoided.

[0058] The device 19 is embodied with an appliance 23 for applying cooling lubricant to a contact area between the grinding tool 22 and the tooth profile 20 during the process of grinding the tooth profile 20 by means of the grinding tool 22.

[0059] Moreover, FIG. 3 shows an enlarged three-dimensional partial view of the gear wheel 21 and the device 19. As can be seen in a combined view of the renderings according to FIG. 2 and FIG. 3, the device 19 comprises a first hollow-cylindrical structural component 25 that is arranged radially inside a second structural component 26 that is also embodied to be hollow-cylindrical at least in certain areas. In the present case, the radially inner first structural component 25 is connected in a torque-proof manner (to an extent that is not shown here in any more detail) to a machine tool which is not shown in any more detail and which provides the drive for the grinding tool 22. The second structural component 26 is arranged and mounted on the first structural component 25 so as to be rotatable in the circumferential direction of the first structural component 25, and is also embodied with a cooling lubricant supply area 27 via which the cooling lubricant can be guided in the manner more closely described below through the first structural component 25 and through the second structural component 26 in the direction of the contact area 24.

[0060] The second structural component 26 comprises guiding means 28A to 28C, which in the present case are embodied in one piece with the first structural component 26 and which are distributed over the circumference of the device 19 in a manner corresponding to the tooth profile 20 of the gear wheel 21. The guiding means 28A to 28C abut a front face 29 of the tooth profile 20 or front faces 29 of the teeth 30 of the tooth profile 21, and thus cover the total tooth profile 20 of the gear wheel 21.

[0061] In the abutment area 31 at the front face 29 of the tooth profile 20, the guiding means 28A to 28C have an outer shape that corresponds to the tooth profile 20, so that a substantially stepless transition is present in the abutment area 31 between the outer sides 32 of the teeth 30 and the lateral walls or lateral surfaces 33 of the guiding means 28A to 28C. In the abutment area 13 at the front surface or the front face 29 of the tooth profile 20, a height of the lateral surfaces 33 of the guiding means 28A to 28C corresponds of a tooth height H between a tooth base 34 and a tooth tip 35. In addition, the height of the lateral surfaces 33 decreases with growing distance in the y-direction or in the axial direction of the gear wheel 21. The guiding means 28A to 28C delimit, to the extent shown in more detail in FIG. 2, a channel 36 that is open towards the grinding tool 22 and arranged so as to be aligned with a tooth intermediate space 37.

[0062] Two conduits 38, 39 or 40, 41 are respectively provided in the guiding means 28A to 28C in the manner shown in FIG. 3. In the present case, the conduits 38, 39 or 40, 41 extend from an interface 42 between the first structural component 25 and the second structural component 26 to the orifice areas 43 to 46 that are provided in the lateral surfaces 33 of the guiding means 28A 28C close to the abutment areas 31. Here, the conduits 39 and 40 open into the channel 36 that is arranged in congruence with the tooth intermediate space 37 between the two teeth 30 of the tooth profile 20 shown in FIG. 3.

[0063] In the abutment area, a width of the guiding means 28A to 28C corresponds 31 to the tooth base width and decreases to the shown extent with increasing distance from the abutment area 31 in the y-direction. Thus, the channel 36 has a profile that widens in y-direction starting at the abutment area 31, and that, during a supply of cooling lubricant to the gear wheel 21 from an additional machine tool-side supply device, can be guided into the tooth intermediate space 37 in a fluidically advantageous manner in addition to the supply via the conduits 39 and 40.

[0064] In the first structural component 25, the cooling lubricant supply area 27 is formed with a cooling lubricant chamber 47 to which cooling lubricant can be applied via a supply opening 48. Here, a length L of the cooling lubricant chamber 47 in the circumferential direction of the device 19 is dimensioned in such a manner that respectively two conduits 39 and 40 that are assigned to a tooth intermediate space 37 are in operative connection with the cooling lubricant supply area 27 which is currently being ground by means of the grinding tool 22, while cooling lubricant is not applied to the further conduits 38, 41 which are assigned to tooth intermediate spaces 37 that are currently not being ground. In continuous processing procedures, such as generation grinding with a threaded grinding wheel, the number of the supplied intermediate grinding spaces is increased corresponding to the number of the intermediate grinding spaces that are ground at the same time.

[0065] Among other things, the described constructional embodiments of the device 19 are based on the fact that in the course of the grinding process the grinding tool 22 is moved through the tooth intermediate space 37 only in the y-direction, and at the end of the grinding process is guided either in the y-direction or in the z-direction out of the meshing area with the tooth profile 20 and also out of the meshing area with the device 19. Subsequently, the gear wheel 21 is rotated together with the guiding means 28A to 28C and with the second structural component 26 in the circumferential direction or in the x-direction until the grinding tool 22 can be inserted into a further tooth intermediate space 19. Here, the first structural component 25 that is connected in a torque-proof manner to the machine tool remains in the position that is shown in FIG. 3, so that the conduits 39 and 40 are no longer connected to the cooling lubricant chamber 47. By twisting the gear wheel 21 and the second structural component 26, the further conduits that are assigned to the tooth intermediate space 37 that is now to be further processed by grinding enter into operative connection with the cooling lubricant chamber 47, and cooling lubricant can be introduced to the desired extent into the tooth intermediate space 37 to be processed.

[0066] Depending on the respectively present application case, there is also the possibility that, instead of the tooth profile of a gear wheel, a tooth profile of a gear rack or of a gear wheel segment is processed by grinding, wherein in that case the device 19 is not embodied in a hollow-cylindrical but likewise in a bar-like or merely segment-like manner.

[0067] If only one tooth flank of a tooth is processed in the course of the grinding procedure of a tooth profile, there is also the possibility of embodying the device with only one guiding means. Further there is also the possibility of designing the device with only two guiding means 28A and 28B, and of respectively twisting the gear wheel 21 with respect to the device 19 until the next teeth to be ground are congruent with the guiding means 28A and 28B.

[0068] The direction in which the cooling lubricant can be guided from the conduits 38 to 41 in the direction of the contact area 24 between the grinding tool 4 and the tooth profile 2 and a rotational direction D of the grinding tool 22 correspond to each other in the contact area 24. Thus, the cooling lubricant that is supplied in the tooth intermediate space 37 is conveyed by the grinding tool 22 to the desired extent into the contact area 24, and grinding burn is avoided to the desired extent.

PARTS LIST

[0069] 1 turbomachine; aircraft engine [0070] 2 main rotational axis [0071] 3 air intake [0072] 4 fan [0073] 5 gear [0074] 6 low-pressure compressor [0075] 7 high-pressure compressor [0076] 8 combustion device [0077] 9 high-pressure turbine [0078] 10 low-pressure turbine [0079] 11 exhaust nozzle [0080] 12 engine nacelle [0081] 13 bypass channel [0082] 14 high-pressure shaft [0083] 15 low-pressure shaft [0084] 16 fan shaft [0085] 19 device [0086] 20 tooth profile [0087] 21 spur gear [0088] 22 grinding tool [0089] 23 appliance [0090] 24 contact area [0091] 25 first structural component [0092] 26 second structural component [0093] 27 cooling lubricant supply area [0094] 28A to 28C guiding means [0095] 29 front face [0096] 30 teeth [0097] 31 abutment area [0098] 32 outer side [0099] 33 lateral surface [0100] 34 tooth base [0101] 35 tooth tip [0102] 36 channel [0103] 37 tooth intermediate space [0104] 38 to 41 conduit [0105] 42 interface between the structural components [0106] 43 to 46 orifice area [0107] 47 cooling lubricant chamber [0108] 48 supply opening [0109] D rotational direction of the grinding tool [0110] H tooth height [0111] L length of the cooling lubricant chamber