Composite shaft with core insert

Abstract

Composite shaft (21), comprising: an elongated annular wave body (22) containing the following: an exterior surface (36); an interior surface that defines a cavity (34); at least one fluid passage (38) defined between the inner and outer surfaces (36); a core insert (32) which is arranged in the cavity (34) and contains the following: an exterior surface (56); an axial fluid conduit (50) which extends at least partially between a first end (46) and a second end (48) of the core insert (32); at least one radial fluid line (52, 54) which is connected to the axial fluid line (50) and the outer surface (56) and is aligned with at least one fluid passage (38), a pin (61) coupling the shaft body (22) to the core insert (32), wherein the pin (61) prevents a rotation of the core insert (32) relative to the shaft body (22), wherein the wave body (22) is made of a first material and the core insert (32) is made of a second material, wherein the density of the first material is greater than the density of the second material, characterized by the fact that the core insert (32) contains a longitudinal channel (58) formed in the outer surface (56) of the core insert (32) and the pin (61) has a first end (62) and a second end (64), wherein the first end (62) is arranged in a radial passage (44) formed in the shaft body (22) and the second end (64) is arranged in the longitudinal channel (58).

Description

[0001] Shafts, such as drive shafts or rotary shafts, are commonly used to transmit power from a rotational energy source, such as the output shaft of a vehicle transmission, to a rotatably driven mechanism, such as a differential. Often, when designing power transmission shafts, the material near the center of the shaft offers few advantages in terms of strength. In such cases, some shafts may be hollow to reduce weight or save on material costs. However, in many instances, it can be beneficial to incorporate channels within the shaft for conveying fluids such as cooling oil and lubricants. When this is the case, the shaft designer must typically leave a suitable amount of material in the center of the shaft to accommodate these channels.As a result, the costs and labor involved in machining the shaft material may be increased.

[0002] WO 2013 / 179591 A1 discloses a gearbox with a rotary shaft. Inside the rotary shaft is a main oil channel with an inlet at one end of the shaft, extending axially from the inlet. Furthermore, a plurality of secondary oil channels are provided, extending radially at axial positions corresponding to the parts requiring lubrication and communicating with an outer circumferential section of the rotary shaft and with the main oil channel. Lubricating oil is conveyed through a grooved section on the main oil channel by the rotation of the rotary shaft in a predetermined direction.

[0003] Furthermore, JP 2014 / 009 744 A discloses a rotating shaft that, by its own rotation, supplies sufficient oil to the depth of a main oil hole. For this purpose, a lubricant conduit structure is proposed in which a main oil hole is formed, extending in the axial direction and connected to radially oriented oil outlet holes. An oil supply pipe is integrated into the main oil hole and is connected to the oil outlet holes via communication holes. A spiral guide groove ensures that the oil is directed from one side of the main oil hole to the other by being moved in a tangential direction by an inertial force generated by the rotation of the shaft.

[0004] German patent application DE 10 2008 056 249 A1 discloses a shaft arrangement comprising a fluid transfer insert located within a bore of a shaft. The fluid transfer insert seals against the shaft and comprises at least one fluid channel connecting a plurality of fluid openings arranged in the shaft. The fluid channel is defined by an outer surface of the fluid transfer insert.

[0005] Furthermore, WO 2014 / 015 253 A1 discloses a bolt arrangement in a planetary gear unit, wherein the bolt arrangement comprises a bolt with a blind hole defined therein. The blind hole extends axially from an opening and terminates with an end face, the bolt comprising an inlet and outlet bore opening laterally into the blind hole. A pin is also provided, which is inserted into the blind hole and has a base and a cylindrical side wall extending from the base. An inlet recess and an outlet recess are formed on the side wall, which are aligned with the inlet bore and the outlet bore of the bolt, respectively, when the pin is inserted into the blind hole.

[0006] US Patent 5,597,370 A further discloses a lubrication device for use with a planetary gear unit. The lubrication device comprises a plug element in which a riser line is integrated. The plug element is inserted into a shaft opening to effectively direct oil to the bearings of a planetary shaft gear.

[0007] Another example is shown in DE 197 27 360 A1 with a hydrostatic-mechanical power-split transmission. The transmission includes a summing planetary gear set and two clutches. To ensure adequate lubrication, particularly for the planet gears of the summing planetary gear set, an oil guide device is provided. This device is designed such that a corresponding oil guide element is inserted into a central oil bore of a bearing pin for a planet gear to be lubricated, with the holder of this oil guide element preferably located in a central oil bore or in a transverse oil bore. The oil guide element forms a component intended for the lubrication of only one planet gear.

[0008] The goal of a gearbox design is usually to reduce mass and inertia to a minimum, so another problem with leaving material in the middle of the shaft is that the mass and therefore the inertia of the shaft cannot be reduced.

[0009] Therefore, there is a need for a way to provide a lightweight shaft design that allows for the accommodation of various lines for guiding fluids and reduces material and machining costs.

[0010] According to the present disclosure, a composite shaft is provided comprising an elongated annular shaft body with an outer surface, an inner surface defining a cavity, at least one fluid passage defined between the inner and outer surfaces, and a core insert arranged in the cavity. The core insert includes an outer surface, an axial fluid channel extending at least partially between a first end and a second end of the core insert, at least one radial fluid channel connected to the axial fluid channel and the outer surface and directed towards the at least one fluid passage, and a pin coupling the shaft body to the core insert, the pin preventing rotation of the core insert relative to the shaft body.The shaft body is made of a first material and the core insert of a second material, the density of the first material being greater than the density of the second material. The core insert includes a longitudinal channel formed in its outer surface, and the pin has a first end and a second end, the first end being arranged in a radial passage formed in the shaft body and the second end being arranged in the longitudinal channel.

[0011] Another aspect of the disclosure is a planetary gear arrangement for torque transmission. The planetary gear arrangement comprises a planet carrier supporting at least one planet gear and an elongated annular shaft body coupling the planet gear to the planet carrier. The shaft body includes an outer surface, an inner surface defining a cavity, at least one fluid passage defined between the inner and outer surfaces, and a core insert located in the cavity. The core insert includes an outer surface, an axial fluid channel extending at least partially between a first end and a second end of the core insert, and at least one radial fluid channel connected to the axial fluid channel and the outer surface and directed toward the at least one fluid passage.The shaft body is made of a first material and the core insert of a second material, the density of the first material being greater than the density of the second material. The core insert includes a longitudinal channel formed in its outer surface and comprises a pin having a first end and a second end, the first end being arranged in a radial passage formed in the shaft body and the second end being arranged in the longitudinal channel, and the pin preventing rotation of the core insert relative to the shaft body.

[0012] These and other aspects and advantages of the composite shaft arrangement disclosed herein will become more understandable upon consideration of the detailed description of the drawings. Fig. Figure 1 is a perspective view of an exemplary planetary gear assembly incorporating a compound shaft according to the present disclosure; Fig. 2 is a disassembled view of some of the components of the planetary gear assembly of Fig. 1; Fig. Figure 3 is a cross-sectional view of the planetary gear assembly along line 3-3 of Fig. 1; and Fig. Figure 4 is an enlarged partial cross-sectional view of the planetary gear assembly along arc 4-4 of Fig. 3, which shows the composite wave arrangement.

[0013] The following detailed description uses the same reference numbers to refer to the same parts from figure to figure.

[0014] As discussed above, in various situations it can be beneficial to provide a suitable device for transmitting power from a rotary drive source to other components in a mechanical arrangement. For example, it can be useful to transfer torque provided by a rotary shaft to a second shaft or gear, such as in a planetary gear arrangement. To improve shaft operation for transmitting rotary force, it can be beneficial to remove some of the material in the center of the shaft. Removing material from the center of the shaft can reduce its mass and improve its inertial characteristics. It can also be beneficial to provide one or more channels within the shaft to allow the passage of fluids, such as cooling oil and lubricants, that may be required during operation.If the shaft is hollow, it may not be possible to provide these fluid lines. Therefore, a shaft designer may have to choose between providing fluid lines and minimizing the shaft's mass. Furthermore, the machining steps required to provide the lines can be difficult with certain shaft materials. For example, machining a steel shaft may be more difficult than machining a less dense or lighter material. However, a heavier material, such as steel, may be necessary to meet specifications, such as the permissible axle load, for the shaft to function properly in a particular application. Various other problems can also arise as the size, complexity, or other specifications of the shaft change.

[0015] The use of the disclosed composite shaft with core insert can address these and other problems. For example, a composite shaft can be provided for the construction of a rotary shaft where it may be advantageous to both reduce mass and provide channels for guiding fluids. The composite shaft can have a hollow annular shaft body and a core insert housed concentrically within the shaft body. The shaft body can be made of a first material, such as steel, and the core insert can be made of a second material with a lower density, such as a polymer. Since the core insert can be less dense than the shaft body, a composite shaft according to the present disclosure can provide a reduction in the overall weight of the shaft compared to a solid, homogeneous shaft made of a single material.Furthermore, the core insert can be chosen for improved machinability compared to the material selected for the shaft body, in order to reduce manufacturing costs, for example.

[0016] One aspect of an exemplary composite shaft according to the present disclosure is that the composite shaft can be used in conjunction with a planetary gear assembly for a work vehicle. In this case, the composite shaft can support a planet gear in a planet carrier. However, any vehicle or other mechanical system can benefit from the use of a composite shaft instead of a solid or hollow shaft, and a planetary gear assembly may not be required to utilize a composite shaft according to the present disclosure. Furthermore, a composite shaft according to the present disclosure can be configured in any suitable shape and size to effectively transmit torque or support a rotating part.For example, it may be useful to specify a larger or smaller ratio for the radius of the insert to the overall radius of the composite shaft than that shown in the example. Similarly, although the length of the insert in the example drawings is shown as approximately equal to the length of the shaft body, the length of the core insert can vary relative to the overall length of the composite shaft. Furthermore, the cross-section of the core insert can differ from that of the shaft body, with suitable core insert cross-sections including circles, squares, triangles, hexagons, multi-pointed stars, and other regular polygons.

[0017] Multiple composite shafts or multilayer composite shafts can also be used. For example, two or more core inserts can be accommodated in a single shaft body. As an example, three concentric layers can constitute a composite shaft, with each layer being made of a different material. One embodiment of a three-layer composite shaft can comprise a steel shaft body with a first annular polymer insert positioned within the shaft body and a cylindrical insert made of a polymer or steel positioned within the first polymer insert. It is also possible for multiple core inserts to be arranged, for example, as parallel cylindrical inserts within a single shaft body that includes several parallel passages to accommodate the inserts.

[0018] In general, the present disclosure provides both stationary and rotating shafts. The disclosed core insert is shown and described as being fixed to the associated shaft body by means of a pin and thus capable of rotating with the shaft body. However, the core insert can be arranged to rotate independently of the shaft body to which it is attached. Likewise, the shaft body and / or the core insert can be arranged to rotate independently of any gear or other part connected to the composite shaft.

[0019] Now on Fig. 1 With reference to this, a schematic representation of an exemplary implementation of a composite shaft construction is shown. In particular, it shows Fig. Figure 1 shows a planetary gear assembly 10, in which various parts have been omitted for clarity. The planetary gear assembly 10 includes a planet carrier 12, which can support several planet gears 14. For clarity, however, only one planet gear 14 is shown. The planet carrier 12 has an axial cylindrical passage 16 with a radially inward splined toothing 20. An axle, drive shaft, or the like (not shown) can be received in the passage 16 and coupled to the splined toothing 20 to rotate the planetary gear assembly 10, as is understood in the engineering. Although this is not explicitly stated in Figure 10, it is understood that the planetary gear assembly 10 can be rotated in the planetary gear assembly 10. Fig. As shown in Figure 1, the planetary gear arrangement can further include additional components, such as a centrally positioned sun gear, a ring gear positioned around the circumference of the planet gears 14, and a varying number of planet gears 14, but are not limited to these. Although a planetary gear arrangement 10 is presented to provide context for the compound shaft of the present disclosure, any system or device containing a shaft can also benefit from the system and methods of the present disclosure. Each of the planet gears 14 can be driven by a compound shaft 21, which is characterized by a (in Fig. The central opening 24 of the planet gear 14 (shown) and openings 26 in opposite surfaces of the planet carrier 12 are coupled to the planet carrier 12. Fastening elements or snap rings 27 can couple the composite shaft 21 and therefore the planet gear 14 to the planet carrier 12.

[0020] Now to the Fig. Referring to 2 - 4, it can be seen that the planet gear 14 can be positioned coaxially to roller bearings 28 and washers 30 next to the composite shaft 21 and the snap rings 27. Fig. Figure 2 also shows that the composite shaft 21 can contain a hollow, annular shaft body 22 and a solid cylindrical core insert 32, which can be arranged in the inner bore or cavity 34 formed in the shaft body 22.

[0021] In particular, the shaft body 22 has a first end 40 and a second end 42. Radial fluid passages 38 can be formed through the shaft body 22 and can open into the surface 36 of the shaft body 22. The radial fluid passages 38 can allow a fluid, such as a lubricant or a coolant, to pass between the exterior of the shaft body 22 and the interior of the cavity 34. When the core insert 32 is positioned in the cavity 34, the radial fluid passages can allow the fluid to access the core insert 32 and any channels or passages contained therein. In the implementation of the system and in the methods of this disclosure, any suitable material can be used to form the shaft body 22.For example, the shaft body 22 can be machine-made, cast or otherwise formed from steel, aluminum, carbon fiber and the like, and alloys and composites thereof.

[0022] The second component of the composite shaft 21 according to the present disclosure is the core insert 32, which can be positioned in the shaft body 22 and can be dimensioned to occupy a substantial part of the cavity 34 or the entire cavity. In one aspect, the outer diameter of the core insert 32 can be substantially equal to the inner diameter of the cavity 34. The core insert 32 can have a first end 46 and a second end 48, corresponding to the first end 40 and the second end 42 of the shaft body 22, respectively. An axial conduit 50 extends from the first end 46 to a location near the second end 48 of the core insert 32 and can further connect with longitudinally spaced radial conduits 52 and 54, which extend radially outward from the axial conduit 50 and terminate in an outer surface 56 of the core insert 32.The core insert 32 can also have a longitudinal channel 58, which is formed in the outer surface 56 and extends from the first end 46 and opening therein to an intermediate point 60 near the second end 48 of the core insert 32. Fig. 3 and Fig. Figure 4 shows that the outer surface 56 of the insert 32 is generally in contact with the inner surface of the cavity 34 along most of the length of the shaft body 22. An exception may be that the inclusion of a channel 58, which accommodates a pin 61, may result in a portion of the core insert 32 not being in contact with the interior of the shaft body 22.

[0023] To achieve a composite shaft with reduced mass compared to a solid shaft, a lower-density material can be selected for the core insert 32. Alternatively, or additionally, a more easily machinable material can be chosen, allowing fluid lines or other passages to be formed more easily compared to shaft body materials such as steel. For example, the core insert 32 can be made from a suitable polymer, such as polyethylene, polypropylene, polystyrene, or copolymers and composites thereof. Furthermore, any suitable manufacturing process can be used to produce the core insert 32. For instance, the core insert 32 can be formed or cast into a cylindrical shape, which can then be machined to provide one or more lines or passages.In one aspect, the core insert 32 can be cast into the cavity 34 of the shaft body 22. In another example, the conduits are formed as part of the molding or casting process. In general, the assembled composite shaft 21 can contain a shaft body 22 with the core insert 32 positioned inside, the shaft body 22 being made of a material of greater density than the core insert 32.

[0024] In some embodiments, the composite shaft 21 can rotate freely about an axis, while in other embodiments the angular position of the composite shaft may be fixed. In one aspect, the position of the composite shaft 21 can be partially fixed by providing a passage 44 in the shaft body 22, as shown in the Fig. Figures 2-4 show the passage 44 opening into the surface 36 near the second end 42 of the shaft body 22. Before positioning the core insert 32 in the cavity 34 with the shaft body 22 positioned in the planet carrier 12, a pin 61 can be positioned in the passage 44. The pin 61 has a first end 62 and a second end 64. The first end 62, which may be chamfered, is guided through the passage 44 and can be received in a passage 66 in the planet carrier 12. The second end 64 of the pin 61 has an enlarged head dimensioned to fit into the channel 58 of the core insert 32. When the core insert 32 is positioned in the shaft body 22, the channel 58 can thus be aligned with the second end 64 of the pin 61, and the core insert 32 can be guided telescopically into the cavity 34.During the insertion process, the second end 64 moves along the length of the channel 58 until the pin 61 abuts the radial edge wall of the channel at position 60 near the second end 48 of the core insert 32.

[0025] The pin provides the functionality of fixing the angular position of the core insert 32 relative to both the shaft body 22 and the planet carrier 12. For example, the planet carrier 12 can be rotated about an axle, drive shaft, or the like, which is received in the passage 16 and coupled to the splined connection 20. After assembly with the pin 61, the composite shaft 21, which contains the core insert 32 and the shaft body 22, can be held in a fixed angular position relative to the planet carrier 12 while the planet carrier 12 is rotated. In particular, the composite shaft 21 may not be able to rotate in openings 26 in opposing faces of the planet carrier 12. Alternatively, the core insert 32 may not be able to rotate relative to the shaft body 22.However, the planet gear 14 can rotate around the composite shaft 21 and, in particular, the shaft body 22.

[0026] The pin 61 can also assist in the alignment of any fluid lines, passages, or through-passes included in the design of the composite shaft 21. As shown in the Fig. 3 and Fig. As shown in Figure 4, the alignment of the shaft body 22 with the planet carrier 12 and the core insert 32 further leads to the alignment of the lines 52 and 54 with the passages 38 and the passage 68. This alignment can, for example, enable a connection of a fluid source with the axial line 50, thereby providing lubrication and / or cooling for the components of the planetary gear assembly 10, such as the roller bearings 28.

[0027] In the illustrated configuration, the radial line 54 can be connected to the passage 68, which in turn can be connected to a fluid source, such as a coolant or lubricant. As a result, the fluid can be supplied from the source to the axial line 50 and the radial line 52. A closure or plug 70, which can be located at one end of the line 50 near the first end 46 of the core insert 32, can prevent fluid from escaping. The plug 70 prevents fluid from exiting the line 50 at the first end 46.

[0028] The Fig. 3 and Fig. Figure 4 also shows the position of the pin 61 relative to the planet carrier 12, shaft body 22, and core insert 32. In particular, it can be seen that the passage 66 in the carrier 12 can be aligned with the passage 44 in the shaft body 22 and the end of the channel 58 near the second end of the core insert 32 to accommodate the pin 61. As mentioned previously, the pin 61 prevents rotation of the composite shaft 21 relative to the planet carrier 12.

[0029] It should be noted that in certain embodiments, the pin 61 and channel 58 features may be omitted. For example, the core insert 32 may be fixed to the shaft body 22 by the use of an epoxy or other adhesive. Alternatively, various fasteners, such as screws, bolts, rivets, and the like, may be used to couple the core insert 32 to the shaft body 22, or a pressure-fit or other friction-based installation method may be employed.

[0030] Although in the Fig.Figures 1-4 show a conduit arrangement. Depending on the arrangement of the specific system or device, alternative conduit arrangements can be implemented. In one aspect, the core insert 32 may contain no conduits, while in another aspect, the core insert 32 may contain multiple conduits, both internal and in contact with the outer surface 56 of the core insert 32. Although the conduits shown are generally cylindrical, conduits with any suitable geometry and cross-section can also be used, such as conduits with a rectangular or other geometric or non-geometric cross-section.

[0031] Furthermore, both the geometry of the core insert 32 and that of the shaft body 22 can differ from the generally cylindrical shape shown in the figures. For example, the core insert 32 and the shaft body 22 can have a non-circular cross-section, such as a square or other geometric or non-geometric cross-section. The cross-section of the core insert 32 can also differ from that of the shaft body 22, and in yet another example, the cross-section of the shaft body 22 or the core insert 32 can differ in the longitudinal direction.

Claims

[1] Composite shaft (21), comprising: an elongated annular wave body (22) containing the following: an exterior surface (36); an interior surface that defines a cavity (34); at least one fluid passage (38) defined between the inner and outer surfaces (36); a core insert (32) which is arranged in the cavity (34) and contains the following: an exterior surface (56); an axial fluid conduit (50) which extends at least partially between a first end (46) and a second end (48) of the core insert (32); at least one radial fluid line (52, 54) which is connected to the axial fluid line (50) and the outer surface (56) and is aligned with at least one fluid passage (38), a pin (61) coupling the shaft body (22) to the core insert (32), wherein the pin (61) prevents rotation of the core insert (32) relative to the shaft body (22), wherein the wave body (22) is made of a first material and the core insert (32) is made of a second material, wherein the density of the first material is greater than the density of the second material, characterized by , that the core insert (32) contains a longitudinal channel (58) formed in the outer surface (56) of the core insert (32) and the pin (61) has a first end (62) and a second end (64), wherein the first end (62) is arranged in a radial passage (44) formed in the shaft body (22) and the second end (64) is arranged in the longitudinal channel (58). [2] Composite shaft (21) according to claim 1, wherein the shaft body (22) and the core insert (32) are coaxial. [3] Composite shaft (21) according to claim 1 or 2, wherein the first material is steel and wherein the second material is a polymer. [4] Composite shaft (21) according to one of claims 1 to 3, wherein the fluid passage (38) is in flow communication with a fluid source. [5] Composite shaft (21) according to any one of claims 1 to 4, wherein the fluid is a coolant or a lubricant. [6] Planetary gear arrangement (10) for torque transmission, comprising: a planet carrier (12) supporting at least one planet gear (14); an elongated annular wave body (22) that couples the planet gear (14) to the planet carrier (12), wherein the wave body (22) comprises the following: an exterior surface (36); an interior surface that defines a cavity (34); at least one fluid passage (38) defined between the inner and outer surfaces (36); a core insert (32) which is arranged in the cavity (34) and contains the following: an exterior surface (56); an axial fluid conduit (50) extending at least partially between a first end (46) and a second end (48) of the core insert (32); and at least one radial fluid line (52, 54) which is connected to the axial fluid line (50) and the outer surface (56) and is aligned with at least one fluid passage (38); wherein the wave body (22) is made of a first material and the core insert (32) is made of a second material, wherein the density of the first material is greater than the density of the second material, characterized by , that the core insert (32) contains a longitudinal channel (58) formed in the outer surface (56) of the core insert (32) and a pin (61) comprising a first end (62) and a second end (64), wherein the first end (62) is arranged in a radial passage (44) formed in the shaft body (22) and the second end (64) is arranged in the longitudinal channel (58), and wherein the pin (61) prevents rotation of the core insert (32) relative to the shaft body (22). [7] Planetary gear arrangement (10) according to claim 6, wherein the shaft body (22) and the core insert (32) are coaxial. [8] Planetary gear arrangement (10) according to claim 6 or 7, wherein the first material is steel and wherein the second material is a polymer. [9] Planetary gear arrangement (10) according to one of claims 6 to 8, wherein the fluid passage (38) is in flow communication with a lubricant source.

Images