Cross hole punching of planetary gear bolts and planetary gear bolts with double-conical fluid conduction holes

Abstract

Method for producing a planetary gear pin (1), in which a planetary gear pin is created from a blank, wherein an opening (2) extending in the longitudinal direction from one end (7, 8) of the planetary gear pin (1) is introduced into the pin, characterized in that at least one fluid conducting through-opening (6) leading from the outer surface (4) defined by the outer contour to the opening (2) is introduced in a tool-falling manner, wherein the planetary gear pin (1) can be produced by cup extrusion with a hole oriented in the longitudinal direction as the opening (2), after which the planetary gear pin (1) is produced by extrusion.

Description

[0001] The invention relates to a method for manufacturing a planetary gear pin, in which a pin is created from a blank, preferably with a circular outer contour in cross-section, wherein an opening extending from one end of the pin in the longitudinal direction is introduced into the pin.

[0002] Planetary gear pins are already known from the prior art, for example from DE 7000388 A1. This discloses a planetary gear pin in a planetary gear that has an inlet tube oriented transversely to the longitudinal axis of the pin. The pin is arranged in a planetary gear such that the planetary gear is rotatably mounted relative to the pin. The pin itself is firmly inserted within a planetary gear support ring. Lubricant, such as oil, is fed from a tray adjacent to the planetary gear through the inlet tube into a through-opening aligned in the longitudinal direction of the pin, so that at a point spaced from the inlet tube, the lubricant can penetrate the pin again through another opening to reach between the planetary gear and the pin, where it acts as a lubricant.

[0003] The interaction of the individual components of a planetary gear is also described in WO 2009 / 100 202 A1.

[0004] DE 103 28 452 B3 also discloses a method for creating a hole on the outer circumference of a hollow profile. Furthermore, DE 10 2010 054 870 A1 also discloses a planetary gear assembly for a transmission. Among other things, DE 10 2005 207 114 A1 also discloses a planetary pin for lubricating planetary gear bearings.

[0005] DE 10 2009 024 027 A1 shows a machine element with at least one rotationally symmetrical hollow body-like section, in which at least the rotationally symmetrical section is formed from two cup-shaped elements which close the machine element at the end and thereby enclose at least one hollow space.

[0006] Furthermore, DE 10 2011 007 801 A1 discloses a bearing pin for a planetary gear, comprising a cylindrical base body, wherein the base body has a radial bore at one axial end. A locking element is provided there to secure the base body against rotation, which locking element is mounted in the radial bore with a radial projection. Such a bearing pin provides a secure fastening option for a bearing pin in a planetary gear that can be implemented with relatively low manufacturing effort. This publication also discloses a support assembly for a planetary gear with such a bearing pin.

[0007] A planetary pin for lubricating planetary gear bearings is also known from DE 10 2015 207 114 A1. In that document, such a planetary pin has a cylindrical body, a first end, an axial path extending from the first end, and a wall thickness between the axial path and an outer surface of the body. A cylindrical transverse path is formed through the wall thickness and axially offset from the first end such that it is in fluid communication with the axial path. A slot extending from the outer surface is formed in the first end such that it intersects the axial path. In that document, the planetary pin unit is described as using a planetary pin, wherein the slot in the first end of the pin cooperates with a planetary carrier to receive lubricant and direct it through the axial path to the transverse path.

[0008] A planetary pin for use in a planetary gear and a system comprising a planetary pin are also known from DE 10 2015 204 198 A1. A planetary pin presented therein provides a plurality of radial paths that are in fluid communication with an axial passage, thereby advantageously eliminating or significantly reducing the need for proper orientation of a planetary pin in a planetary gear.

[0009] Also noteworthy is DE 10 2006 004 720 B4, which discloses a bolt in a planetary drive with a chamfer sloping towards a front side of the bolt at at least one end of the bolt, wherein it is particularly emphasized that the front side of the bolt has at least one fracture point.

[0010] Planetary gear pins with laterally extending through holes or two blind holes containing transverse openings, i.e., radially aligned openings, are already known. Lubricant, such as oil, is collected in the lateral holes, i.e., the longitudinally aligned openings, or the longitudinally aligned opening, and then fed to the transversely aligned holes. These radially / transversely aligned holes are also typically used to conduct lubricant or insert locking pins so that the planetary gear pin can be installed precisely in a predefined position. Typically, however, the transverse holes, which represent fluid-conducting through holes, are created by machining, i.e., drilling. This is discussed, for example, in DE 10 2015 204 198 A1 and DE 10 2015 207 114 A1.The functions of these fluid conduction openings are also specifically described in DE 7000388 A1.

[0011] However, the conventional machining of the transverse holes is relatively costly and laborious. In particular, burrs protrude radially inward on the inside of the fluid passage opening, thus protruding into the longitudinal opening. These burrs then have to be laboriously removed before the planetary gear pin can be used. This is time-consuming and costly.

[0012] Furthermore, it is desirable to precisely align the planetary gear pins during installation. This is advantageous for force transmission, but also important for achieving lubricant flow, particularly by utilizing centripetal forces and / or by aligning different lubricant guide channels / fluid guide openings. WO 2009 / 100 202 A1, DE 10 2011 007 801 A1, and DE 10 2015 207 114 A1 are also active in this area.

[0013] However, it has not yet been possible to provide simple measures to simplify assembly. Typically, a large number of manufacturing steps are necessary to create assembly markings, which are then helpful during assembly, i.e., the alignment of the individual parts relative to one another. Creating assembly markings is complicated and costly. However, the object of the present invention is precisely to provide a remedy and, preferably, to mitigate or even completely eliminate the disadvantages of the prior art. In particular, costs should be reduced and the manufacturing process should be faster and easier to implement.

[0014] This problem is solved in a generic method by forming at least one fluid passage opening extending from the outer surface defined by the outer contour to the laterally aligned opening. In this way, a planetary gear pin of very high quality can be produced not only quickly but also cost-effectively.

[0015] Advantageous embodiments are claimed in the subclaims and are explained in more detail below.

[0016] It is therefore advantageous if the fluid passage opening is created without cutting. Non-cutting manufacturing processes have the potential to produce consistently high-quality planetary gear pins at low cost. This clever combination of both advantages is achieved here.

[0017] A particular embodiment is characterized in that the fluid conduction passage opening aligned transversely to the longitudinal axis of the bolt is punched inwards.

[0018] The invention also relates to a planetary gear pin for use in a planetary gear, such as a spur gear differential of a motor vehicle, between a planet carrier and a planet gear, having a first end and a second end, wherein an opening extends from at least one of the two ends into the pin in the longitudinal direction of the pin, wherein at least one fluid conducting through-opening extends from the outer circumferential surface into the (lateral) opening and runs from an inlet on the side of the (lateral) opening to an outlet in the outer circumferential surface (oriented obliquely / transversely to the longitudinal axis of the pin).

[0019] An inventive improvement of this generic planetary gear pin is achieved in that the fluid conduction passage opening has a cross-section that is smallest between the inlet and the outlet and at a distance from them. Thus, the cross-section changes from large to small to large, viewed from the inside to the outside.

[0020] It is advantageous if, in a particular embodiment, the fluid conducting passage opening in the region of the outlet has a configuration that narrows radially inwards in a funnel shape and / or widens radially inwards from the point of the smallest cross section in the direction of the inlet, preferably progressively.

[0021] In order to enable cost-efficient and fast production, it is advantageous if the fluid conduction opening is designed as a non-cutting transverse punch hole.

[0022] It is advisable for the longitudinally aligned opening to be designed as a blind hole or through hole. Of course, two blind holes are also possible. These blind holes are then separated from each other by a crosspiece.

[0023] It has also proven effective to design the fluid passage opening as a lubricant channel or, in a special modification, as a locking pin receiving hole. In the latter case, pre-adjusted locking pins can be inserted into the locking pin receiving hole to ensure optimal alignment of the individual parts.

[0024] It is also advantageous if the fluid conducting passage opening has a radially outer edge fracture region, i.e., a region in which it exhibits elasto-plastic deformation. Furthermore, the fluid conducting passage opening has a preferably (approximately) cylindrical smooth-cut region radially inwardly adjacent to the edge fracture region, and a residual fracture region / tear-out region radially inwardly adjacent to the smooth-cut region, which is approximately conically widening.

[0025] Finally, the invention also relates to a planetary gear for a drive train of a motor vehicle with a planet carrier into which a planetary gear pin according to the invention is inserted and which rotatably supports a planetary gear.

[0026] The invention also relates to a planetary gear pin for use in a planetary gear transmission, such as a spur gear differential of a motor vehicle, between a planet carrier and a planetary gear, having a first end and an opposite second end, wherein an opening extends from one end into the pin along the longitudinal axis of the pin, wherein an assembly mark in the manner of a recess is present at one or both ends. Such a planetary gear pin can be further developed in that the assembly mark is arranged at the end on the radial inside of the opening in the material of the flow-formed pin. This embodiment can also be pursued without the features of the independent patent claims, for example in a divisional application.

[0027] That embodiment can also be further developed in that the assembly marking is designed as an orientation feature in the manner of a plastic deformation mark.

[0028] It is therefore advantageous if a wall section of the bolt is provided radially outside the recess. In other words, the recess is embossed at one end on the inside of the wall section.

[0029] The invention also relates to a planetary gear for a drive train of a motor vehicle with a planet carrier in which such a planetary gear pin is inserted and which overlies a planetary gear.

[0030] In this context, a method should also be mentioned that implements a further concept of the invention. This concept concerns the production of a planetary gear pin of the type according to the invention, wherein the assembly marking is / is introduced into the pin without cutting during the extrusion of the pin. This makes production faster and more cost-effective.

[0031] In other words, the goal is to provide a manufacturing process for radial openings for planetary gear (gearbox) pins / planetary gear bearing pins with robust and cost-effective, process-ready series production. The radial openings, which function as lubricating oil holes or locking pin holes, are now created by cross-hole punching. Edge breaks or roundings on these fluid passage openings are also created by forming. In addition, the planetary gear pins can have orientation features, e.g. rivets, notches, or similar, which enable targeted alignment of the lubricating oil holes during assembly. The pin blanks to be punched can be produced by forming or machining. The planetary gear pins are used in transmissions. They serve as carriers for gears in planetary gears. The gears run on rolling elements, which in turn roll on the cylindrical surface of the planetary gear pin.

[0032] Planetary gear pin blanks for planetary gears are typically machined from metallic material, such as 100Cr6 or 16MnCr5. The flow-direction through holes are typically machined, as are the longitudinally aligned hole(s). Any orientation features are also machined and typically extend across the entire width of the planetary gear pin. It is desirable for the ratio of wall thickness to bore diameter to be on the order of 1, especially when using a through-hardening steel such as 100Cr6.

[0033] It is now proposed to convert the manufacturing process for the radial holes on the planetary gear pin from machining to forming. The goal of this change is to reduce costs in hole creation and deburring effort. The functionality of the holes for the lubricating oil supply and the mounting of a locking pin is nevertheless ensured.

[0034] A fluid passage opening is now being promoted by means of cross-hole punching and edge rounding. While previously, a cylindrical hole was created during machining, a different geometric design is now possible. Previously, a chamfer was usually created as an edge break at the transition to the outer diameter of the bolt. Unfortunately, large drill burrs typically occur at the transition to the inner diameter of the bolt, which require laborious removal. This is undesirable and is eliminated with the solution according to the invention.

[0035] The cross-cut punching process according to the invention creates a hole with a varying diameter. The hole diameter increases from the bolt's outer diameter to the bolt's inner diameter. The hole consists of a smooth-cut portion with a cylindrical shape and a residual fracture zone with a conical shape. At the transition to the bolt's outer diameter, an edge break in the form of a rounded portion or chamfer is stamped. The transition to the inner diameter is virtually burr-free. This results in savings in deburring.

[0036] The ratio of wall thickness to hole diameter, where the wall thickness is measured only on one side of the longitudinal axis, is usually between 0.7 and 1.5 for work-hardened materials such as 100Cr6 or 16MnCr5.

[0037] The tapered design of the oil lubrication hole plays only a minor role in functional performance, as it barely affects the oil flow rate. However, tapered locking pin holes must be considered when designing the pin connection.

[0038] Cross-hole punching now provides a cost-effective and robust alternative to machining the radial bore on planetary gear pins. With regard to the formation of burrs, a higher strength of the pin material, such as that resulting from work hardening during extrusion of the blank, is advantageous for punching.

[0039] The radial openings, i.e. the flow-guiding through-openings, can be attached to the planetary gear pin, where the axial opening / inner bore is designed as a through-bore / through-hole or as a blind hole / blind hole.

[0040] Any number of fluid passages for the lubricating oil supply can be arranged at various levels of the cylinder / planetary gear pin. Typically, one or two radially aligned fluid passages are located circumferentially distributed in the center plane of the cylinder / planetary gear pin.

[0041] The fluid passage opening for accommodating a locking pin is located on the outer diameter near the end face. Additional orientation features can be provided on the planetary gear pin, at least one of which enables precise alignment of the radial openings, i.e., the fluid passage openings, during assembly of the planetary gear pins.

[0042] The focus of the invention is therefore a method for producing fluid conduction through-holes / transverse holes in planetary gear pins by punching. The invention also focuses on a planetary gear pin with such transverse holes / fluid conduction through-holes created by punching. It has proven significant that, within the scope of the invention, a planetary gear pin with transverse holes / fluid conduction through-holes can also be produced, with each hole / fluid conduction through-hole having a constriction zone with a rough surface material. It should be noted that the planetary gear pin can be produced by cup extrusion with a longitudinally aligned (blind / through) hole / lateral (blind / through) hole, with the pin being produced by extrusion.

[0043] However, the invention also relates to a planetary gear pin, which is advantageously produced by extrusion and has an assembly mark on the inside or an edge, at an entrance on the inner cylindrical side of the through hole or blind hole aligned in the lateral direction / longitudinal direction in the manner of the opening already mentioned.

[0044] The invention is explained in more detail below with the aid of a drawing. Various embodiments are described, which may also be the subject of divisional applications. They show: Fig. 1 a longitudinal section through a first embodiment of a planetary gear pin according to the invention with a blind hole-like opening aligned in the longitudinal direction and two fluid through-openings, Fig. 2 an enlargement of area II from Fig. 1, Fig. 3 a second embodiment of a planetary gear pin according to the invention, with a first fluid conducting passage opening provided for the passage of lubricating oil and a further fluid conducting passage opening for receiving a locking pin. Fig. 4 shows a further embodiment of a planetary gear pin according to the invention in a longitudinal section corresponding to Fig. 1 and Fig. 3, but with two blind-hole-like openings extending in the longitudinal direction, Fig. 5 shows a further embodiment with an assembly marking in the form of a recess in a longitudinal section, and Fig. 6 an enlargement of area VI from Fig. 5.

[0045] The figures are merely schematic and serve only to clarify the invention. The same elements are provided with the same reference numerals. Features of the individual embodiments can be interchanged.

[0046] In Fig. Figure 1 shows a first embodiment of a planetary gear pin 1 according to the invention. The planetary gear pin 1 is made from a blank and has an opening 2 extending in the longitudinal direction. The longitudinal direction is defined by a rotation axis / axis of symmetry / longitudinal axis 3.

[0047] The planetary gear pin 1 has an outer surface 4 with a circular outer contour when viewed in cross-section. A fluid conducting through-hole 6 extends from the outer surface 4 through the wall 5. Specifically, two fluid conducting through-holes 6 are present in one and the same transverse plane. The fluid conducting through-holes 6 are oriented transversely, in particular orthogonally, to the rotational axis / axis of symmetry / longitudinal axis 3 of the planetary gear pin 1. The planetary gear pin 1 has a first end 7 and a second end 8. A recess 9 is present at the second end 8. The opening 2 extends to a transverse rib 10 adjacent to the recess 9.

[0048] The fluid passage openings 6 are formed without cutting, in particular by forming, specifically by punching, namely by cross-punching. They extend exactly in the radial direction. However, deviations of up to 5° are acceptable.

[0049] In Fig. 2 shows an enlargement of the wall 5 in the area of ​​a fluid conducting passage opening 6. The fluid conducting passage opening 6 extends from an inlet 11 on the radial inside of the wall 5 to an outlet 12 on the outer surface 4. In the narrowest area of ​​the fluid conducting passage opening 6, a diameter d is measured. The wall 5 has a thickness s. The ratio s to d is between 0.7 and 1.5. In the area of ​​the inlet 11, there is a residual fracture area 13. This residual fracture area 13 is followed by a smooth cut area 14, which in the Fig. 2 is almost zero. Further radially outward, this smooth cutting area 14 is followed by an edge break area 15.

[0050] In the Fig. 3 and Fig. 4 shows two further embodiments, wherein the fluid conduction opening 6 closer to the end is provided for receiving a locking pin. The two fluid conduction openings 6 in each of the two planetary gear pins 1 of the Fig. 3 and Fig. 4 are, however, identical.

[0051] In the Fig. 5 to 6, a special embodiment is shown with an assembly marking 16, wherein the assembly marking is designed in the manner of a recess 17, for example as a plastic deformation mark. List of reference symbols 1 planetary gear bolt 2 Opening 3 Rotation axis / symmetry axis / longitudinal axis 4 outer surface / outer surface / outer surface 5 Wall 6 Fluid conduction opening 7 first end of the bolt 8 second end of the bolt 9 Deepening 10 transverse ribs 11 Entrance of the fluid conduction opening 12 Outlet of the fluid passage opening 13 Residual fracture area 14 Smooth cutting area 15 Edge break area 16 Assembly marking 17 Recess

Claims

[1] Method for manufacturing a planetary gear pin (1), in which a planetary gear pin is created from a blank, wherein an opening (2) extending from one end (7, 8) of the planetary gear pin (1) in the longitudinal direction is introduced into the pin, characterized by that at least one fluid conducting through-opening (6) leading from the outer surface (4) defined by the outer contour to the opening (2) is introduced in a tool-like manner, wherein the planetary gear pin (1) can be produced by cup extrusion with a hole oriented in the longitudinal direction as the opening (2), after which the planetary gear pin (1) is produced by extrusion. [2] Method according to claim 1, characterized by that the fluid conduction opening (6) is introduced without cutting. [3] Method according to one of claims 1 or 2, characterized bythat the fluid conduction passage opening (6) aligned transversely to the longitudinal axis (3) of the planetary gear pin (1) is punched inwards. [4] Method according to one of claims 1 to 3, characterized by that several fluid conduction openings (6) are introduced in one work step. [5] Planetary gear pin (1) for use in a planetary gear between a planet carrier and a planet gear, with a first end (7) and a second end (8), wherein from at least one of the two ends (7, 8) an opening (2) extends into the planetary gear pin (1) in the longitudinal direction thereof, wherein from the outer circumferential surface (4) into the opening (2) at least one fluid conducting through-opening (6) extends from an inlet (11) on the side of the opening (2) to an outlet (12) in the outer circumferential surface (4), characterized bythat the fluid conducting passage opening (6) designed as a non-cutting transverse punched hole has a cross section which is smallest between the inlet (11) and the outlet (12) and at a distance from these. [6] Planetary gear bolt (1) according to claim 5, characterized by that the fluid conducting passage opening (6) in the region of the outlet (12) has a configuration which narrows radially inwards in a funnel shape and / or widens radially inwards from the point of the smallest cross-section in the direction of the inlet (11). [7] Planetary gear bolt (1) according to claim 5 or 6, characterized by that the fluid conduction passage opening (6) is designed as a non-cutting transverse punching hole. [8] Planetary gear bolt (1) according to one of claims 5 to 7, characterized by that the longitudinally oriented opening (2) is designed as a blind hole or through hole. [9] Planetary gear for a drive train of a motor vehicle, with a planet carrier into which a planetary gear pin (1) according to one of claims 5 to 8 is inserted and which rotatably supports a planetary gear.

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