Device for transmitting a torque with a device for measuring the transmitted torque, in particular for a transverse stabilizer

Abstract

Device (100) for transmitting a torque (M) with a device for measuring the transmitted torque (M), comprising a hollow shaft (10) and a measuring component (20), wherein the measuring component (20) is arranged in the interior of the hollow shaft (10) and is connected to the hollow shaft (10) in at least one connection area (I, II), characterized in that an indirect brazed connection (32) is formed in at least one connection area (II) between the measuring component (20) and the inner wall (12) of the hollow shaft (10), such that the measuring component (20) is arranged in a bearing bushing (60) or in an installation sleeve and the bearing bushing (60) or the installation sleeve is brazed to the inner wall (12) of the hollow shaft (10), wherein the brazed connection (32) is formed between an outer circumferential surface of the bearing bushing (60) or the installation sleeve and the inner wall (12) of the hollow shaft (10).

Description

[0001] The invention relates to a device for transmitting torque, comprising a device for measuring the transmitted torque. The invention further relates to a method for producing such a device, as well as to a transverse stabilizer, in particular for a motor vehicle, comprising at least one such device.

[0002] Methods and devices for measuring the torsion of a pipe are generally known in the prior art, in particular in DD 279 311 A1, US 4 972 725 A, and GB 1 045 467 A. AT 118 183 B proposes a fixed mounting for a torsion dynamometer. DE 10 2008 002 065 A1 also discloses an arrangement for detecting torque on a hollow shaft of a transmission, in which a detection device is arranged inside the hollow shaft. CH 266 678 A describes a measuring device with a torsion bar as a force-directing element. The torsion bar has a different cross-sectional shape between the attachment points than at the attachment points, in order to keep the torsional strength higher at the attachment points than in between.

[0003] A device for transmitting torque with a device for measuring the transmitted torque is known from EP 0 254 754 A1. The previously known device comprises a hollow shaft and a device inserted within the hollow shaft for measuring or detecting the torque transmitted by the hollow shaft. The device for measuring the transmitted torque comprises a measuring shaft (transmission tube) welded to the inner wall of the hollow shaft. However, such a welded connection is problematic because it can have a detrimental effect on the structure of the hollow shaft and because the production of such a welded connection requires accessibility to the weld point.

[0004] It is therefore an object of the present invention to provide a device for transmitting a torque with a device for measuring the transmitted torque, which does not require such a welded connection and which can be manufactured in particular with relatively low manufacturing costs.

[0005] This object is achieved by a device according to the invention having the features of claim 1.

[0006] With the first subordinate claim, the solution to the problem also extends to a method for producing the device according to the invention.

[0007] Preferred and / or advantageous embodiments and further developments are specified in the respective dependent claims. The features in the dependent claims, as well as the following explanations, apply analogously to both the device according to the invention and the claimed method for its production.

[0008] With the second independent claim, the solution to the problem also extends to a transverse stabilizer, preferably for the chassis of a motor vehicle and in particular for the chassis of a passenger car, which comprises at least one device according to the invention.

[0009] For a better understanding of the invention, reference is expressly made to the German patent application DE 10 2010 027 959 of the same applicant.

[0010] The device according to the invention comprises a hollow shaft and (at least) one measuring component, wherein the measuring component is (at least partially) arranged in the interior of the hollow shaft and is connected to the hollow shaft in at least one connection area, in particular connected in a rotationally fixed manner. It is provided that an indirect brazed connection is formed between the measuring component and the inner wall of the hollow shaft in at least one connection area.

[0011] The measuring component is arranged at least in sections in at least one bearing bush or in an installation sleeve, wherein the bearing bush or the installation sleeve is brazed to the inner wall of the hollow shaft. A bearing bush can, for example, accommodate measuring electronics. The measuring component can be partially and, in particular, completely (i.e., including all relevant components) accommodated in an installation sleeve, so that during production, for example, a pre-assembled assembly unit can be provided which can be inserted or introduced into the interior of the hollow shaft with little effort. For further explanation, reference is also made to DE 10 2010 027 959. The brazed connection is preferably formed between an outer peripheral surface of the bearing bush or the installation sleeve and the inner wall of the hollow shaft.The brazed joint essentially extends only in the peripheral areas of the contact area, whereby the solder used can be distributed selectively or over the entire surface.

[0012] It is preferably provided that the brazed connection in this connection area extends over the entire circumference of the inner wall of the hollow shaft.

[0013] A brazed joint is understood to be a soldered joint produced in a known manner using a suitable solder (hard solder) at a soldering temperature of more than 450°C. Such a brazed joint is a materially bonded connection. A brazed joint does not have the disadvantages mentioned above in connection with a welded joint, or only to a reduced extent. Furthermore, a brazed joint can be produced with a device according to the invention with relatively little effort, as explained in more detail below.

[0014] The hollow shaft has an axial longitudinal extension and any cross-section. Preferably, the hollow shaft is tubular with a circular cross-section (or a similar cross-section, such as an oval cross-section).

[0015] A measuring component is a component belonging to the device for measuring the transmitted torque, which performs or fulfils a mechanical function when measuring the torque transmitted by the hollow shaft. In particular, this is a measuring shaft. Such a measuring shaft also has an axial longitudinal extent with any cross-section. The measuring shaft can be designed as a hollow shaft or as a solid shaft. It is preferably provided that the hollow shaft and / or the measuring shaft have a cross-section that changes over their longitudinal extent. Both the hollow shaft and the measuring shaft (the same applies to a measuring component) can be designed as a single piece or in multiple pieces. However, a single-piece design is preferred in each case. A rotationally fixed connection in a connection area primarily serves to measure torques between the hollow shaft and the measuring component orthe measuring shaft, which enables the measurement of the torque transmitted by the hollow shaft, as explained in more detail below.

[0016] The proposed brazed joint between the measuring component and the hollow shaft can fulfill various functions. The brazed joint can, for example, serve to secure the measuring component's axial position within the hollow shaft. Furthermore, the brazed joint can serve to secure the axial position of the measuring component within the hollow shaft. Securing the axial position of the measuring component within the hollow shaft using a brazed joint can also be useful when a non-rotatable connection between the measuring component and the hollow shaft is essentially achieved through a positive connection (e.g., a splined shaft-like connection, screw connection, pin connection, or the like). Another function can be to seal the interior.

[0017] The hollow shaft and the measuring component arranged in the interior of the hollow shaft can be designed in at least one connection area such that a direct or immediate brazed connection can be formed between the measuring component and the inner wall of the hollow shaft. However, it is preferably provided that the measuring component is brazed to the inner wall of the hollow shaft in at least one connection area using at least one intermediate piece (or the like) or a bearing bush (or the like) (as explained in more detail below), which is referred to as an indirect or mediate brazed connection. Furthermore, both direct and indirect brazed connections can be provided between the measuring component and the hollow shaft on a hollow shaft according to the invention, which are then distributed across several connection areas.

[0018] Preferably, at least one intermediate piece can be arranged on the measuring component, which is brazed to the inner wall of the hollow shaft. This intermediate piece can be connected to the measuring component in a rotationally fixed manner (a one-piece design with the measuring component is also conceivable) and can create a connection (or bridging) between the measuring component and the inner wall of the hollow shaft in the connection area. Such an intermediate piece can, for example, be plate-shaped or disk-like. Preferably, such an intermediate piece is arranged at an end section of the measuring component (or the measuring shaft). In particular, it is provided that such intermediate pieces are arranged at both end sections of the measuring component (or the measuring shaft), both of which are brazed to the inner wall of the hollow shaft in different sections that are axially spaced from one another.It can be provided that such an intermediate piece is adapted with its outer contour to the inner contour of the hollow shaft (possibly positively connected). The brazed connection is preferably made between an outer peripheral surface of the intermediate piece and the inner wall of the hollow shaft. The brazed connection can extend essentially over the entire contact area between the outer peripheral surface of the intermediate piece and the inner wall of the hollow shaft or only over a portion of this contact area. The brazing material used can be distributed selectively in this contact area. However, a full-surface distribution of the brazing material in the contact area is preferred.

[0019] Preferably, the hollow shaft is made of a hardened steel material, as explained in more detail below. Furthermore, it is preferably provided that the hollow shaft is open at one axial end and, in particular, is formed with a widened portion or an increasing diameter at this axial end. This improves accessibility to the interior of the hollow shaft. Furthermore, the widened portion provides a larger flange surface, for example, for connection to an actuator (as explained in more detail below).

[0020] The method claimed in the first independent claim for producing a device according to the invention comprises (at least) the following steps: - Providing a hollow shaft, a measuring component and a bearing bush or in a mounting sleeve; - Equipping the hollow shaft by inserting the measuring component and the bearing bush or the installation sleeve into the interior of the hollow shaft and introducing solder into the connection area of ​​the bearing bush or the installation sleeve; - heating the assembled hollow shaft, whereby the solder liquefies and forms an indirect brazing connection between the measuring component and the inner wall of the hollow shaft in the connection area, such that the brazing connection is made between an outer circumferential surface of the bearing bush or the installation sleeve and the inner wall of the hollow shaft; and - optional subsequent insertion of measuring electronics (into the interior of the hollow shaft).

[0021] A stop can be formed in the hollow shaft, which can be used to specify an axial position for the measuring component within the hollow shaft. Heating the hollow shaft equipped with the measuring component and the solder can be carried out in a heating furnace. However, inductive heating is preferred. The claimed method can include further steps and / or intermediate steps that are not explained in detail here.

[0022] Preferably, the hollow shaft is hardened, for which purpose the hollow shaft equipped with the measuring component, the bearing bush or the installation sleeve and the solder is heated and then deliberately cooled, whereby the solder liquefies upon heating and forms the indirect brazed connection between the measuring component and the inner wall of the hollow shaft in the relevant connection area. In this way, the brazing process can be integrated into a hardening process, so to speak, whereby the manufacturing effort can be kept low, particularly if hardening of the hollow shaft is planned anyway. Furthermore, energy advantages result. Hardening is provided, for example, if the device according to the invention is to be used in a transverse stabilizer (as explained in more detail below).

[0023] To harden the hollow shaft, it must be made of a hardenable steel material. The heating temperature is in the range between 800°C and 1000°C, and the heated hollow shaft must be held at the heating temperature for a certain period of time (holding time) to allow the desired structural changes to occur and for the brazing material to liquefy. Heating can be carried out in a furnace and / or inductively. After heating and a defined holding time, targeted cooling is required. Given the relatively high temperatures involved in the hardening process, the integrated brazing process can be a so-called high-temperature brazing process (temperatures above 900°C).

[0024] The claimed method for producing a device according to the invention is particularly suitable for cases in which the interior of the provided hollow shaft is only accessible via one axial end. The one-sided accessibility of the interior in torque-transmitting hollow shafts is a frequently encountered circumstance in practice, which can particularly also occur when the device according to the invention is a component for a transverse stabilizer (as explained in more detail below). Even in the case of such one-sided or otherwise poor accessibility, the manufacture of the device according to the invention is possible by inserting the measuring component (and all associated components) into the interior of the hollow shaft from the accessible end and brazing it directly or indirectly to the inner wall of the hollow shaft for fastening in at least one connection area.Heat can be applied externally and / or inductively for brazing, especially since the interior of the hollow shaft is essentially no longer accessible after the measuring component has been inserted. The measuring electronics are only inserted into the interior via the accessible axial end after brazing and, if necessary, hardening.

[0025] With the second subordinate claim, the solution to the problem also extends to a transverse stabilizer, preferably for the chassis of a motor vehicle and in particular for the chassis of a passenger car, which comprises at least one device according to the invention. In particular, it is provided that this transverse stabilizer is an adjustable or adjustable transverse stabilizer. For this purpose, the transverse stabilizer is known to be split, with an actuator inserted at the split point, which rotates the connected stabilizer shafts (stabilizer halves) relative to each other depending on the situation in order to be able to influence or change, for example, the rolling behavior of the vehicle body when cornering (see relevant explanations in DE 10 2010 027 959). The stabilizer shafts connected to the actuator are preferably devices according to the invention.The torques measured on these devices can be used to control or regulate the actuator.

[0026] Further features and advantages of the invention will become apparent from the following explanations with reference to the figures. Fig. 1 shows a schematic sectional view of an embodiment of a device according to the invention for transmitting a torque with a device for measuring the transmitted torque. Fig. Figure 2a shows an enlarged schematic sectional view of a connection area on the device of Fig. 1 before a brazing process. Fig. Figure 2b shows the same joint area after a brazing process.

[0027] Fig. 1 shows a device 100 according to the invention for transmitting a torque with a device for measuring the transmitted torque. This device 100 is a component (stabilizer half) for a transverse stabilizer that is or can be installed in the chassis of a passenger car. The device 100 comprises a hollow-cylindrical hollow shaft 10, which has an expansion 11 with an increasing diameter at one axial end. Access E to the interior of the hollow shaft 10 is also located at this end. The device 100 can be connected to the expansion 11 with an actuator for dynamically influencing the stabilization properties (as explained above). The longitudinal axis is designated L. A torque that can be transmitted by the hollow shaft 20 is illustrated by the rotation arrow M.

[0028] The measurement of the torque M transmitted by the hollow shaft 10 is carried out in a fundamentally known manner, namely by measuring the elastic rotation or torsion of a second section of the hollow shaft 10 relative to a first section of the hollow shaft 10 resulting from the torque transmission. For this purpose, a measuring component in the form of a measuring shaft 20 is arranged in the interior of the hollow shaft 10, which is connected in a rotationally fixed manner at its first axial end in a first connection area I to the first section of the hollow shaft 10 and at its second axial end in a second connection area II to the second section of the hollow shaft 10.Due to the rotationally fixed connection in the two connection areas I and II, the torsion of the hollow shaft 10 (between the first section and the second section) is transmitted to the measuring shaft 20, so that the torque M transmitted between the first section of the hollow shaft 10 and the second section of the hollow shaft 10 can be determined from the torsion of the measuring shaft 20 between its first axial end and its second axial end. The measurement or detection of the torque M transmitted by the hollow shaft 10 also works when the second axial end of the measuring shaft 20 is not connected to the second section of the hollow shaft 10, by measuring or detecting the rotation of the second section of the hollow shaft 10 relative to the second axial end of the measuring shaft 20. By using such a measuring component or such a measuring shaft 20, further possibilities for measuring the torque M transmitted by the hollow shaft 10 are possible.

[0029] In the first connection area I, the rotationally fixed connection between the first end section of the measuring shaft 20 and the first section of the hollow shaft 10 is established by means of a plate-shaped intermediate piece 40, which is arranged in a rotationally fixed manner on the measuring shaft 20. The plate-shaped intermediate piece 40 can also be formed integrally with the measuring shaft 20. In the second connection area II, the rotationally fixed connection between the second end section of the measuring shaft 20 and the second section of the hollow shaft 10 is established by means of a cage 50 (or the like) and a bearing bush 60. The cage 50 can be formed integrally with the bearing bush 60. The plate-shaped intermediate piece 40 and the bearing bush 60 (together with the cage 50) function as a support for the measuring shaft 20.

[0030] In the cage 50, a measuring electronics unit (such as a rotary motion sensor or a torque sensor; see also the explanations in DE 10 2010 027 959) is arranged, which is not shown or explained in detail. This electronic unit measures the twisting of the measuring shaft 20 between its first end section and its second end section, from which the torque M transmitted between the first section of the hollow shaft 10 and the second section of the hollow shaft 10 can be determined, as explained above. Based on this measurement, for example, the actuator explained above can be regulated or controlled to dynamically influence the stabilization properties of the anti-roll bar.

[0031] According to the invention, an indirect brazed connection is provided between the measuring shaft 20 and the inner wall 12 of the hollow shaft 10 in both the first connection area I and the second connection area II. In the first connection area I, a brazed connection 31 is provided between the outer peripheral surface of the plate-shaped intermediate piece 40 and the inner wall 12 of the hollow shaft 10. This brazed connection 31 extends essentially over the entire contact area between the outer peripheral surface of the plate-shaped intermediate piece 40 and the inner wall 12 of the hollow shaft 10. In the second connection area II, a brazed connection 32 is provided between the outer peripheral surface of the bearing bush 60 and the inner wall 12 of the hollow shaft 10. This brazed connection 32 extends essentially only in the edge regions of the contact area between the outer peripheral surface of the bearing bush 60 and the inner wall 12 of the hollow shaft 10, as can be seen from Fig. 2b.

[0032] The bearing bush 60 is described below with reference to the Fig. 2a and Fig. 2b explains the brazed joint 32 between the outer peripheral surface of the bearing bush 60 and the inner wall 12 of the hollow shaft 10 and the production of such a brazed joint 32, wherein these explanations also apply analogously to the brazed joint 31 between the outer peripheral surface of the plate-shaped intermediate piece 40 and the inner wall 12 of the hollow shaft 10.

[0033] Fig. Figure 2a shows the second fastening area II in an enlarged view before the brazing process. The measuring shaft 20, the cage 50, and the bearing bush 60 are already located in the interior of the hollow shaft 10. In the contact area defined by the bearing bush 60 with the inner wall 12 of the hollow shaft 10, a gap 33 is formed between the outer peripheral surface of the bearing bush 60 and the inner wall 12 of the hollow shaft 10. A brazing agent 30 is applied to both axial edges of the bearing bush 60 (or possibly only to one edge of the bearing bush 60) in the form of several packages (inlays) distributed around the circumference or in the form of a closed ring. To secure its position and with a view to simple assembly, the brazing agent 30 can be attached, for example, to the annular end faces of the bearing bush 60. Additionally, a flux can be provided, with which, for example, the brazing agent 30 is coated or mixed.

[0034] In the Fig. In the state shown in Figure 2a, the hollow shaft 10 equipped with the measuring shaft 20 and the solder 30 is heated and maintained at this heating temperature (e.g., in the range between 800° C and 1000° C) for a defined period of time. This is indicated by the arrow labeled Q (heat) and t (time) between the Fig. 2a and Fig. 2b. Due to the heat effect, the solder 30 liquefies and, due to capillary action, penetrates from both sides into the gap 33 between the bearing bush 60 and the inner wall 12 of the hollow shaft 10. This results, after cooling, in a brazed joint which, depending on the amount and design of the gap 33, extends across the entire axial width of the bearing bush 60 or is formed only in the edge regions of the contact area between the bearing bush 60 and the inner wall 12 of the hollow shaft 10, as shown in Fig. 2b. The brazed joint 32 can extend selectively around the circumference or can extend completely around the entire circumference.

[0035] In the illustrated embodiment, the gap 33 between the bearing bush 60 and the inner wall 12 of the hollow shaft 10 is necessary due to the capillary action during the brazing process. After cooling, a press-fit-like condition can be created due to the brazing material located between the inner wall 12 of the hollow shaft 10 and the outer circumferential surface of the bearing bush 60. The gap 33 can be omitted under certain circumstances, for example, if a clever combination of materials succeeds in achieving different thermal expansion of the hollow shaft 10 and the bearing bush 60 during heating, so that a gap is formed during heating into which the brazing material 30 can penetrate. In addition to or as an alternative to a brazing material 30 applied to the axial edges of the bearing bush 60 (see Fig. 2a) it can be provided that the solder is introduced into recesses on the outer peripheral surface of the bearing bush 60 and melts out of these recesses when heated.

[0036] To achieve a good brazed joint 32, it is preferably provided that the hollow shaft 10 and the bearing bush 60 are formed from the same metal material, in particular from the same steel material, or at least from similar metal materials, in particular from similar steel materials. A composite material (e.g., a ceramic composite) may also be considered for the bearing bush 60.

[0037] Preferably, a combined hardening and soldering process is provided, wherein the heat applied to harden the hollow shaft 10 simultaneously leads to the melting or liquefaction of the solder 30, as explained above. This essentially combines two manufacturing steps into a single manufacturing step.

[0038] To prevent damage to the measuring electronics, they are inserted into the cage 50 only after the device 100 has been heated and cooled. However, it is not necessary for the measuring electronics to be inserted immediately after cooling. Further protection of the measuring electronics can be achieved, for example, by inserting them at a later point in time, for example, shortly before the device 100 is installed.

Claims

[1] Device (100) for transmitting a torque (M) with a device for measuring the transmitted torque (M), comprising a hollow shaft (10) and a measuring component (20), wherein the measuring component (20) is arranged in the interior of the hollow shaft (10) and is connected to the hollow shaft (10) in at least one connecting region (I, II), characterized by that in at least one connection area (II) an indirect brazed connection (32) is formed between the measuring component (20) and the inner wall (12) of the hollow shaft (10), such that the measuring component (20) is arranged in a bearing bush (60) or in a mounting sleeve and the bearing bush (60) or the mounting sleeve is brazed to the inner wall (12) of the hollow shaft (10), wherein the brazed connection (32) is formed between an outer circumferential surface of the bearing bush (60) or the mounting sleeve and the inner wall (12) of the hollow shaft (10). [2] Device (100) according to claim 1, characterized bythat the brazed connection (32) extends over the entire circumference of the inner wall (12) of the hollow shaft (10). [3] Device (100) according to one of the preceding claims, characterized by that the hollow shaft (10) is made of a hardened steel material. [4] Device (100) according to one of the preceding claims, characterized by that the hollow shaft (10) is open at one axial end (E) and is formed with an expansion (11). [5] A method for manufacturing a device (100) according to any one of the preceding claims, comprising the following steps: - Providing a hollow shaft (10), a measuring component (20) and a bearing bush (60) or an installation sleeve; - Equipping the hollow shaft (10) by inserting the measuring component (20) and the bearing bush (60) or the installation sleeve into the interior of the hollow shaft (10) and introducing solder (30) into the connection area (II) of the bearing bush (60) or the installation sleeve; - heating the assembled hollow shaft (10), whereby the solder (30) liquefies and forms an indirect brazed connection (32) between the measuring component (20) and the inner wall (12) of the hollow shaft (10) in the connection area (II), such that the brazed connection (32) is made between an outer circumferential surface of the bearing bush (60) or the installation sleeve and the inner wall (12) of the hollow shaft (10); and - subsequent insertion of measuring electronics. [6] Method according to claim 5, characterized bythat the hollow shaft (10) is hardened, for which purpose the hollow shaft (10) equipped with the measuring component (20), the bearing bush (60) or the installation sleeve and the solder (30) is heated and subsequently cooled in a targeted manner, wherein the solder (30) liquefies during heating and the indirect brazed connection (32) between the measuring component (20) and the inner wall (12) of the hollow shaft (10) is formed in the relevant connection area (II). [7] Method according to claims 5 and 6, characterized by that the interior of the provided hollow shaft (10) is only accessible via one axial end (E). [8] Transverse stabilizer, preferably for the chassis of a motor vehicle and in particular for the chassis of a passenger car, comprising at least one device (100) which is designed according to one of the preceding claims 1 to 4 and / or which is manufactured according to a method according to one of the preceding claims 5 to 7.

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