Connection system and connection arrangement

Abstract

The present invention relates to a connection system with a first element (20) and a second element (22), wherein the first element (20) and the second element (22) can be inserted into one another for connection to one another. The first element (20) has a cutting toothing (26) which, upon insertion, cuts a corresponding tooth profile (32) into the second element (22) in a cutting direction (34). The second element (22) has a chip removal groove (60) which, upon reaching an assembly position, causes chips to be removed from the second element (22) by the cutting toothing (26). The invention also relates to a connection arrangement.

Description

[0001] The present invention relates to a connection system with which two elements can be connected to each other with corresponding toothings, particularly for a bicycle. The invention also relates to a connection arrangement.

[0002] It is known to join two components together with a cutting tooth system. This involves pressing two components together, with one of the two components cutting a tooth system into the other component with a cutting tooth system. However, the resulting chips can counteract the pressing together. For example, a chip can prevent further pressing in even though the components have not yet reached their desired assembly position. Furthermore, a chip compressed by pressing can cause a spring effect, which pushes the pressed-in component out of the desired final position.

[0003] From DE 23 47 372 A1 a positive connection of two components is known, in which one of the two components has teeth with cutting surfaces which, when the two components are pressed together, cut a toothing in the other component.

[0004] DE 10 2007 000 659 A1 discloses a positive connection between two interlocking components equipped with a toothing. Guide surfaces are provided to center the two components relative to each other during the connection.

[0005] JP 2011-225 153 A relates to preventing a decrease in the fixing force between an outer coupling element and a hub by optimizing the contact area between the pin head and the pin receptacle. This is achieved by press-fitting the axial portion of the coupling outer ring into the bore of the hub, creating a toothing between the two parts that allows axial separation and is secured by pins.

[0006] JP 2011 - 131 641 A relates to preventing undue expansion of a hub circle and improving the adhesion of the gear teeth by precisely controlling the shape of the projection forming the gear teeth between the axial portion of the outer clutch element and the hub circle. This is achieved by pressing the axial portion of the clutch outer ring into the bore of the hub circle, creating a gear teeth that are secured by bolts and allow axial separation.

[0007] It is therefore an object of the present invention to propose a connection system that is improved over the prior art. This object is achieved by the subject matter having the features of the independent patent claims. Preferred developments are set forth in the subclaims.

[0008] A first aspect relates to a connection system with a first element and a second element. The two elements can, for example, be components of a drive train. For example, the first element can be a shaft and the second element can also be a shaft. The shafts can, for example, be designed as a motor shaft and a shaft of a transmission. For example, the first element can be a pedal crankshaft of a bicycle and the second element a rotating element of a planetary gear of the bicycle. For example, the two elements can form the pedal crankshaft of a bicycle after they have been connected to one another. One of the two elements can also be designed, for example, as a stationary component, such as a housing. The connection system can be designed to join the two elements together. The connection system can be designed to produce a defined press fit between the two elements.The two elements can also be connected with a transition fit or loose fit.

[0009] The first element and the second element can be inserted into one another for connection to one another. For example, the second element can have a recess into which the first element can be at least partially inserted. Conversely, the first element can also have a recess into which the second element can be at least partially inserted. The examples described below, in which the first element is inserted into the second element, also apply equally to embodiments in which the second element is inserted into the first element. The two elements can be moved relative to one another for insertion. The two elements can be permanently connected to one another by insertion. A connecting arrangement can be produced from the two elements by insertion. The connecting arrangement can be a two-part component. The two elements can be pressed together during insertion.The recess in one of the two elements for receiving the other of the two elements can be configured to correspond to an outer contour of an insertion section of the other of the two elements. The recess in one of the two elements for receiving the other of the two elements can, for example, be cylindrical.

[0010] The first element has cutting teeth. The cutting teeth can have teeth and a front-side cutting area for each tooth. The teeth of the cutting teeth can be arranged on a circumference of the first element. The cutting area can be designed, for example, as a cutting edge or cutting surface. A toothing area can adjoin the cutting area, via which a torque can be transmitted from the first component to the second component after they have been connected to one another. The cutting area cuts, for example, a material of the second element upon insertion, for example on a facing surface. The toothing area does not further cut the material of the second element upon insertion, for example. The torque can be transmitted, for example, via respective tooth flanks of the cutting teeth, such as the tooth flanks of the toothing area.The first element can, for example, be hardened in the cutting area. The first element can, for example, be made of a harder material than the second element. The cutting teeth extend axially, for example, only over a portion of the first element. The cutting teeth can, for example, protrude radially, for example, toward the second element after insertion.

[0011] The cutting teeth are designed to cut a corresponding tooth profile into the second element in a cutting direction during insertion. The cutting direction can, for example, correspond to a direction of insertion of the first element into the second element. The cutting direction can, for example, be a direction in which the material is cut from the second element during insertion. In the process, a chip is formed, for example per tooth of the cutting teeth. The chip is pushed in front of the cutting teeth, for example through the cutting area. The cutting direction can run from a point which is cut first during insertion to a point which is cut last during insertion. The cutting direction can be parallel to a longitudinal axis of the first component and, alternatively or additionally, of the second component.The cutting direction can be coaxial with a longitudinal axis of a recess of one of the two components. The tooth profile can have teeth in a corresponding number to the teeth of the cutting toothing of the first element. The teeth of the tooth profile can be arranged on a circumference of the second element. Torque can be transmitted between the first component and the second component via the tooth profile after they have been connected to one another. The torque can be transmitted, for example, via respective tooth flanks of the tooth profile. The tooth flanks of the tooth profile and the cutting toothing can abut one another after the two elements have been connected to one another. The first element and, alternatively or additionally, the second element can have a cylindrical basic shape in the region of the connecting arrangement, the cutting toothing and the tooth profile.The cutting teeth and the tooth profile can form a positive connection after connecting the first element to the second element.

[0012] The second element has a chip removal groove. When an assembly position is reached, the chip removal groove causes the cutting teeth to be separated from the second element. For example, the cutting area of ​​the cutting teeth can break into the chip removal groove with the chip pushed in front of it, thereby causing chip separation. For example, the cutting teeth can break through a wall of the chip removal groove and thus be pushed into the chip removal groove. Complete chip removal or at least partial chip removal can occur. All chips or at least just one chip can be separated from a tooth of the tooth profile of the second element. There can be one chip per tooth of the cutting teeth. If descriptions below refer to one chip, these can equally apply to multiple chips, where applicable. The chip removal groove can, for example, be designed as a circumferential groove.However, a separate chip removal groove can also be provided for each tooth of the cutting toothing. The assembly position can be a desired connection position between the two elements. The assembly position can be a final position when connecting the two elements. The assembly position can be defined, for example, by a stop.

[0013] Chip separation allows the chip to fall into a chip chamber. Chip separation prevents the chip from hindering the two elements from moving into their final assembly position, for example because the chip blocks the full insertion of the first element into the second element at the end face of the cutting toothing. In addition, compression of the chip in the assembly position, which can tension the chip like a spring, can be avoided. This tension of an uncut chip can cause a high force that pushes the two elements out of their assembly position. It has been recognized that even a chip that is not compressed in the final position can cause a spring effect during operation and thus push the two elements out of their assembly position. This effect can be prevented by separation.Accordingly, axial fixation, for example, using a fixing element, can be less effective because the potential chipping force of an uncut chip does not have to be resisted. This allows a fixing screw to have a smaller diameter. Furthermore, the overall clamping force required to hold the two elements together in the assembly position can be lower.

[0014] In addition, the chip removal groove can facilitate assembly. At the end of a press-in process, the press-in force may drop as the chip is removed. This allows a press report to show that the assembly position has been reached. Without chip removal, however, the force required for pressing may increase continuously upon reaching the assembly position without any intermediate drop. It may then be unclear whether the press is already being applied against a stop or simply against a jammed chip.

[0015] For the connection system, it is provided that a wall of the chip removal groove facing the cutting direction is steeper than a wall of the chip removal groove facing away from the cutting direction. The wall of the chip removal groove facing the cutting direction can, for example, be broken through by the cutting teeth when the assembly position is reached. The wall of the chip removal groove facing away from the cutting direction is, for example, not reached by the cutting teeth when the assembly position is reached. The steepness of a wall can be defined by an angle to the cutting direction. For example, the wall of the chip removal groove facing the cutting direction can extend orthogonal to the cutting direction. For example, the wall of the chip removal groove facing away from the cutting direction can extend at an angle of less than 90° to the cutting direction.The steeper the wall of the chip removal groove facing the cutting direction, the shorter the chip removal groove can be. This can also result in better chip removal. A flatter angle of the wall of the chip removal groove facing the cutting direction can simplify the production of the chip removal groove. Furthermore, the force gradient when breaking through this wall through the cutting toothing can be lower.

[0016] In a further embodiment of the connection system, it can be provided that the cutting toothing protrudes into the chip removal groove with its front end region in the cutting direction in the cutting direction in the assembly position. The chip removal groove can be arranged such that, for example, the cutting region and optionally also a part of the toothing region protrudes into the chip removal groove in the assembly position. This can ensure chip removal. For example, the chip removal grooves are arranged axially in the same area in the assembly position of the two elements. The cutting edge can thus be at least partially or completely spaced from the walls of the chip removal groove or even entirely from the second element.

[0017] In a further embodiment of the connection system, it can be provided that the chip removal groove extends further in a vertical direction than respective teeth of the cutting toothing. At least the front end region which projects into the chip removal groove can, for example, be less high than the chip removal groove. The vertical direction can, for example, be a radial direction. In the case of the teeth of the cutting toothing, the vertical direction can correspond to an extension from the bottom to the tooth tip. A tooth tip of a tooth of the cutting toothing can therefore be less high than the chip removal groove. This allows the chip to be separated particularly cleanly upon reaching the assembly position. The front end region of the cutting toothing can be accommodated in a free space without contact with the second element. The chip removal groove can enlarge a chip chamber for the chips created when cutting the tooth profile.This can, for example, make cutting an axially long gear considerably easier.

[0018] In a further embodiment of the connection system, it can be provided that the connection system has a fixing element. The connection system can be designed to fix the first element to the second element in the cutting direction by means of the fixing element. For example, the fixing element can block axial movement of the two elements relative to one another in the cutting direction. This can reliably prevent the two elements from becoming loose from one another, for example due to vibrations. The fixing element can be designed, for example, as a screw or dowel pin. For example, the second element can have a through-opening through which the fixing element is pushed and engages with an internal thread of the first element. The two elements can then be fixed to one another by tightening the screw. In addition, the fixing element can also be used to push the two elements into one another.For example, by tightening the screw, the first element can be pressed into the second element. By tightening the screw, the tooth profile can then be cut with the cutting teeth. This makes assembly particularly simple and requires only a few steps. The connection system can be designed to use the fixing element to pull the first element and the second element into one another in a cutting direction for connecting them to one another, cutting the tooth profile, and forming the press connection. Alternatively or additionally, a press can be provided for this purpose.

[0019] In a further embodiment of the connection system, it can be provided that the second element has a recess for inserting the first element. For example, the second element can have a cylindrical through-opening or a cylindrical blind hole into which a corresponding section of the first element with the cutting teeth can be inserted. The second element can have a radial recess at the end in the cutting direction, for example at the bottom. This radial recess can form a further groove, which, however, only simplifies the production of the recess and does not collect any chips in the connected state. The cutting teeth can be formed on an outer circumference of the first element. For example, the first element with the cutting teeth can thus cut the tooth profile on an inner circumference of the recess of the second element.The production of the cutting teeth on the outer circumference of the first element can be particularly simple and cost-effective. The chip removal groove can be formed on an inner circumference of the second element, which, for example, defines the recess. The chip removal groove can be spaced axially from an end region of the recess and the bottom-side radial recess, opposite to the cutting direction.

[0020] In a further embodiment of the connection system, it can be provided that the first element has a recess for the insertion of the second element. The cutting toothing can be formed on an inner circumference of the recess of the first element. The chip removal groove can be formed on an outer circumference of the second element. For example, the recess of the first element slides along this outer circumference during insertion. The design here can therefore be the opposite of the previously described embodiment. For example, the first element can have a cylindrical through-opening or a cylindrical blind hole into which a corresponding section of the second element can be inserted. The tooth profile can then be cut in this section of the second element. For example, the first element with the cutting toothing can thus cut the tooth profile on an outer circumference of the second element.The cutting teeth on the inner circumference of the first element can be well protected from damage before the two elements are joined together.

[0021] In a further embodiment of the connection system, it can be provided that the first element and the second element are designed to abut against one another in the cutting direction when connected to one another. This can specify a defined connection position or assembly position. For example, the first element can abut against a bottom of the blind hole when inserted into the recess in the second element, which is designed as a blind hole. A defined assembly position can then be reached. The abutment can also be formed, for example, by a protruding region of the first element, which abuts on the outside against a wall of the recess in the second element when inserted.

[0022] In a further embodiment of the connection system, it can be provided that the first element has a first fitting surface in front of the cutting teeth in the cutting direction. The first fitting surface can guide the first element and the second element during insertion. The first fitting surface can also absorb bending loads. The second element can have a first fitting surface corresponding to the first fitting surface of the first element. These two first fitting surfaces can be arranged adjacent to one another in the connected state, for example, abutting one another in the same axial region of the pedal crankshaft. The two first fitting surfaces can, for example, form a loose fit, transition fit, or interference fit. A fit in the region of the first fitting surfaces can be tighter than in the region of the teeth.For example, the first mating surface of the first element can be formed by a cylindrical section in front of the cutting teeth in the cutting direction. The first mating surface of the first element can, for example, ensure concentricity of the two elements when inserted into one another before starting a cutting process of the tooth profile. The first mating surface of the first element can be separated from the cutting teeth, for example, by a circumferential cutting relief groove. This can prevent the mating surface from interfering with the cutting process.

[0023] In a further embodiment of the connection system, it can be provided that the first element has a second fitting surface behind the cutting teeth in the cutting direction. The second fitting surface can also support bending loads. The second element can have a second fitting surface corresponding to the second fitting surface of the first element. These two second fitting surfaces can be arranged adjacent to one another in the connected state, for example, abutting one another in the same axial region of the pedal crankshaft. The two second fitting surfaces can, for example, form a loose fit, a transition fit, or an interference fit. A fit in the region of the second fitting surfaces can be tighter than in the region of the teeth. For example, the second fitting surface of the first element can be formed by a cylindrical section behind the cutting teeth in the cutting direction.The second mating surface can also be in contact with another crankshaft component or drivetrain component, for example, to support bending forces. For example, the second mating surface can be in contact with a bottom bracket. The second mating surface of the first element can be separated from the cutting teeth, for example, by an additional circumferential groove. This can facilitate manufacturing.

[0024] In a further embodiment of the connection system, it can be provided that the first element has a cutting relief groove in front of the cutting teeth in the cutting direction. The cutting relief groove can be arranged in the cutting direction between the cutting teeth and the fitting surface. The cutting relief groove can be designed as a circumferential groove. A separate cutting relief groove can also be provided for each tooth of the cutting teeth. The cutting relief groove allows the chip to escape in the cutting relief groove before reaching the assembly position during the cutting process, whereby joining forces can be low. In the assembly position, the cutting relief groove can form a chip chamber with the chip removal groove. Separated chips can be accommodated in the chip chamber. In the assembly position, the cutting relief groove can be arranged at least partially overlapping with the chip removal groove.The cutting relief groove can be connected to the chip removal groove in the mounting position.

[0025] In a further embodiment of the connection system, it can be provided that a toothing region of the cutting toothing has a constant cross-section. This can make the production of the cutting toothing cost-effective. Furthermore, this can create a continuous, uniform toothing between the two elements. For example, the cutting toothing can have a constant height and a constant width after the cutting edge. A cross-section can, for example, only change at respective axial ends of the cutting toothing, for example, to transition into the fitting surfaces and alternatively or additionally form the cutting edge.

[0026] A second aspect relates to a connecting arrangement having a first element and a second element. The connecting arrangement is formed from the connecting system according to the first aspect. Respective further features, embodiments, and advantages can be found in the descriptions of the first aspect. Conversely, features, embodiments, and advantages of the second aspect also represent features, embodiments, and advantages of the first aspect. The connecting arrangement can, for example, form a two-part crankshaft of a bicycle, such as a pedelec.

[0027] The first element of the connecting arrangement has a cutting toothing and the second element of the connecting arrangement has a corresponding tooth profile. The tooth profile was cut by the cutting toothing when the first element and the second element were inserted into one another. The cutting toothing and the tooth profile can form a press fit, transition fit or loose fit. The second element has a chip release groove which, for example, when the first element and the second element were inserted into one another and an assembly position was reached, caused a chip to be separated from the second element by the cutting toothing. The connecting arrangement can have the separated chip. The chip can be accommodated in the chip release groove and alternatively or additionally in a cutting relief groove.

[0028] A further aspect relates to a drive train of a bicycle having the connection arrangement according to the second aspect. Yet another aspect relates to a bicycle having such a drive train. Further features, embodiments, and advantages can be found in the descriptions of the second and first aspects. Conversely, features, embodiments, and advantages of the second and first aspects also represent features, embodiments, and advantages of the further aspects. Fig. 1 shows a schematic sectional view of a pedal crankshaft with a first element and a second element.

[0029] Fig. Figure 1 shows a schematic sectional view of a pedal crankshaft with a first element 20 and a second element 22. The two elements 20, 22 are designed as pedal crankshaft parts. The second element 22 has a cylindrical recess 24 into which the first element 20 has been inserted with a cylindrical end portion. Thus, the pedal crankshaft is formed from a connecting system with the two elements 20, 22.

[0030] The first element 20 has on its outer circumference in an axial partial area a cutting toothing 26, which is formed by radially outer teeth 28. To connect the two elements 20, 22 to one another, the first element 20 is inserted into the second element 22 along its axial extent in an insertion direction and thus cutting direction towards a bottom of the recess 24. The bottom of the recess forms a stop for the first pedal crankshaft part 20, thereby defining an assembly position. The cutting direction is in Fig.1 by arrow 34. At the bottom, the recess has a manufacturing-related recess. At a front end of the cutting toothing 26 in this cutting direction, each of the teeth 28 of the first pedal crankshaft part 20 has a cutting area 30. This cutting area 30 cuts into an inner circumference of the second pedal crankshaft part 22 in the recess 24 a tooth profile 32 corresponding to the cutting area of ​​the cutting toothing 26. In this case, a chip is cut from the second element 22 for each tooth 28 of the cutting toothing 26. The tooth profile 32 has a constant cross-section along its longitudinal extent in the cutting direction. The teeth of the tooth profile 32 of the second pedal crankshaft part 22 have a constant height and a constant width.

[0031] The second element 22 has a through-opening 36 at a bottom of the recess 24. A fixing element in the form of a screw 38 is arranged in the through-opening 36. The screw 38 fixes the first element 20 to the second element 22 in the cutting direction and thus axially. For this purpose, the screw 38 engages with an internal thread in a through-opening 42 of the first element 20.

[0032] By tightening the screw 38, the first element 20 can also be pulled into the recess 24 for connecting the two elements 20, 22 and thus pressed in. During this pulling and thus insertion of the first element 20 into the second element 22, the tooth profile 32 is also cut into the second crankshaft part 22. Alternatively, the pressing in can be performed using a press without using the screw 39.

[0033] The first element 20 has, at its end facing the bottom of the recess 24 and thus at the front in the cutting direction, in front of the cutting teeth 26 and the cutting area 30, a first cylindrical end piece 44 which forms a first fitting surface on its outer circumference. The first fitting surface guides the first crankshaft part 20 and the second crankshaft part 22 against each other during insertion and ensures concentricity of the two elements 20, 22 before cutting of the tooth profile 32 begins. Furthermore, in the connected state shown, the first fitting surface bears against a corresponding fitting surface of the second crankshaft part 22. The first fitting surfaces can thus support bending loads. The first fitting surface and the end piece 44 are axially separated from the cutting teeth 26 by a circumferential cutting relief groove 46 in the first crankshaft part 20.When cutting the tooth profile 32 into the second element 22, the respective chips are collected and carried along in the cutting relief groove 46. As a result, the resulting chips have less of an impact on the cutting of the tooth profile 32.

[0034] The first crankshaft part 20 has a second cylindrical end piece 50 facing away from the bottom of the recess 24 and thus behind the cutting teeth 26 and the cutting area 30 in the cutting direction. This second cylindrical end piece 50 forms a second fitting surface on its outer circumference. This second fitting surface rests against a bottom bracket in a section not shown and also absorbs bending loads.

[0035] The second element 22 has a circumferential chip removal groove 60 on the inner circumference, which delimits the recess for receiving the first element 20. When the assembly position is reached, a chip is separated from the second element 22 by the cutting toothing 26 through the chip removal groove 60. In the assembly position, the cutting toothing 26 projects with its front end region in the cutting direction 34 into the chip removal groove in the cutting direction, whereby a chip is separated. In the example shown, the cutting toothing 26 projects at least an average or maximum chip thickness into the chip removal groove 60 axially or in the cutting direction. In the example shown, this is 0.4 mm. As a result, the chip is cleanly separated by each tooth 28 of the cutting toothing 26 onto a wall of the chip removal groove 60 facing the cutting direction 34 as it breaks through the groove.The chip removal groove 60 extends in a vertical direction, which here is a radial direction, further than the respective teeth 28 of the cutting toothing 26. A tooth top of the teeth 28 of the cutting toothing 26 is thus exposed in the chip removal groove 60. The wall of the chip removal groove 60 facing the cutting direction 34 is steeper relative to the axial extension of the second element 22 and thus the cutting direction 34 than a wall of the chip removal groove 60 facing away from the cutting direction 34.

[0036] In the assembly position, the chip removal groove 60 and the cutting edge relief groove 46 are arranged overlapping in an axial region and thus connected to each other. The chip removal groove 60 and the cutting edge relief groove 46 together form a chip space in which separated chips are accommodated. The chip space has a size at least corresponding to the volume of the separated chips. Reference symbol 20 first element 22 second element 24 cylindrical recess 26 cutting teeth 28 teeth 30 cutting area 32 tooth profile 34 Arrow / Cutting direction 36 Through opening of the second element 38 Screw / fixing element 42 Passage opening of the first element 44 first end piece / fitting surface 46 Cutting relief groove 50 second end piece / fitting surface 60 chip removal groove

Claims

[1] A connection system comprising a first element (20) and a second element (22), wherein the first element (20) and the second element (22) can be inserted into one another for connection to one another, wherein the first element (20) has a cutting toothing (26) which, upon insertion, cuts a corresponding tooth profile (32) into the second element (22) in a cutting direction (34), wherein the second element (22) has a chip removal groove (60) which, upon reaching an assembly position, causes chips to be removed from the second element (22) by the cutting toothing (26), characterized by that a wall of the chip removal groove (60) facing the cutting direction (34) is steeper than a wall of the chip removal groove (60) facing away from the cutting direction (34). [2] Connection system according to claim 1, characterized bythat the cutting toothing (26) projects into the chip removal groove (60) with its front end region in the cutting direction (34) in the cutting direction (34) in the assembly position. [3] Connection system according to claim 1 or 2, characterized by that the chip removal groove (60) extends further in a vertical direction than the respective teeth (28) of the cutting toothing (26). [4] Connection system according to one of the preceding claims, characterized by that the connection system has a fixing element (38), wherein the connection system is designed for fixing the first element (20) to the second element (22) in the cutting direction (34) by means of the fixing element (38). [5] Connection system according to one of the preceding claims, characterized by that the second element (22) has a recess (24) for the insertion of the first element (20) and the cutting teeth (26) are formed on an outer circumference of the first element (20). [6] Connection system according to one of claims 1 to 4, characterized by that the first element (20) has a recess (24) for the insertion of the second element (22) and the cutting teeth (26) are formed on an inner circumference of the recess (24) of the first element (20). [7] Connection system according to one of the preceding claims, characterized by that the first element (20) and the second element (22) are designed to abut one another when connected to one another in the cutting direction (34). [8] Connection system according to one of the preceding claims, characterized by that the first element (20) has a first fitting surface (44) in front of the cutting teeth (26) in the cutting direction (34). [9] Connection system according to one of the preceding claims, characterized by that the first element (20) has a cutting relief groove (46) in front of the cutting teeth (26) in the cutting direction (34). [10] Connection arrangement characterized by a connection system according to one of the preceding claims, comprising a first element (20) and a second element (22) which are inserted into one another, wherein the first element (20) has a cutting toothing (26) and the second element (22) has a tooth profile (32) corresponding thereto, which was cut by the cutting toothing (26) when the first element (20) and the second element (22) were inserted into one another, wherein the second element (22) has a chip removal groove (60) which, when the first element (20) and the second element (22) were inserted into one another and an assembly position was reached, caused a chip removal from the second element (22). [11] Drivetrain for a bicycle characterized by a connecting arrangement according to claim 10.

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