Torque sensor having radially elastic material portion

Abstract

The present invention relates to a torque sensor (10) having an axially and circumferentially extending body (12) extending radially from an annular inner flange (18) having a first force introduction point (16), through a mechanically weak sensor section (20) equipped with a measurement sensor for generating an output signal, to an annular outer flange (32) having a second force introduction point (34), the second force introduction point being connected to the sensor section via a radially elastic material section (28). The radially elastic material section (28) is formed by a plurality of radially elastic bending strips (31) distributed around the entire circumference of the body and is connected to the mechanically weak sensor section (20) via a radially rigid annular decoupling area (27).

Description

[Technical field]

[0001] The present invention relates to a torque sensor having a body extending in the axial and circumferential directions and extending radially from an annular inner flange having a first force introduction point, via a mechanically weak sensor part with a measuring transducer for generating an output signal, to an annular outer flange having a second force introduction point, the second force introduction point being connected to the sensor part via a radially elastic material part. [Background technology]

[0002] Such a torque sensor is known from WO 2018 / 041948. With this known torque sensor, a large decoupling in the radial direction can be achieved, i.e. it is possible to prevent radially directed forces acting on the torque sensor from leading to measurement errors. Such radially directed forces can result, for example, from out-of-roundness at the second force introduction point caused by manufacturing tolerances. Such out-of-roundness can result in crosstalk of the measuring transducers. In order to avoid measurement errors that can be caused by radially acting forces, in the known torque sensor, the radially elastic material part is formed as a recess (thin-walled material part) extending in the axial direction of the body. Due to its thin-walled form, this radially elastic material part has a low stiffness against radial deformations, but is substantially stiff against torsional forces, i.e. has a high stiffness against torsional forces. However, the recess extending in the axial direction in the known torque sensor results in an increase in the axial dimension of the entire torque sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 041948 Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the invention is to provide a torque sensor which maintains the insensitivity of known torque sensors to mechanical interferences, in particular to radially acting forces, and which furthermore makes it possible to realize a more compact construction form. [Means for solving the problem]

[0005] The above object is achieved by a torque sensor of the aforementioned generic type, in which the radially elastic material portion is formed by a plurality of radially elastic bending strip portions (strip portions) distributed around the periphery of the body, the radially elastic material portion being connected to the mechanically weaker sensor portion via an annular radially stiff decoupling area (non-interference area).

[0006] The radially elastic bending strips can be easily designed so that they require less or at least no more installation space in the axial direction than the remaining area or part of the body. For example, the bending strips can be formed by a series of slots passing through the radially elastic material in the axial or radial direction. The slots preferably extend at least substantially in the circumferential direction, but embodiments are also possible in which the slots have a straight or straight-bent profile. Within the scope of the present disclosure, the term "slot" means in particular that the width of the opening formed by the slot is much smaller than the longitudinal extent of the opening.

[0007] The number of radially elastic bending strips can be selected relatively freely. In order to achieve a good decoupling (non-interference) with respect to radially acting forces, it is preferred that at least three bending strips are arranged in an orderly manner distributed over the entire circumference of the body. However, it is particularly preferred that more than three radially elastic bending strips are provided, for example four, five, six, seven or eight radially elastic bending strips. It is easily possible to provide a significantly higher number of radially elastic bending strips, for example even sixteen radially elastic bending strips. The number of radially elastic bending strips actually used can depend on the construction and size of the body, in particular on the space available in the body. In principle, a higher number of radially elastic bending strips allows for a uniform decoupling with respect to radially acting forces, but even three or four radially elastic bending strips are sufficient for a good decoupling with respect to radially acting forces.

[0008] By providing an annular radially stiff decoupling region between the weak sensor region and the radially elastomeric material, forces absorbed by the radially elastomeric material are prevented from affecting the weak sensor region, i.e., the annular radially stiff decoupling region is unaffected or substantially unaffected by the weak sensor region occurring in the radially elastomeric material region.

[0009] Overall, the use of radially elastic bending strips in the configuration of the radially elastic material section, in combination with the annular radially stiff decoupling area, allows the second force introduction point, the radially elastic material section, the annular decoupling area, the weak sensor section and the first force introduction point to have a common radial cross section. In such a configuration, when viewed from the radially inner side, the first force introduction point, the sensor section, the annular decoupling area, the radially elastic material section and the second force introduction point follow each other in the radial direction. In addition to such a radial extent, both the sensor section and the radially elastic material section, the annular decoupling area and the first and second force introduction points have an axial extent, which is necessary in all cases for reasons of stability. The first and second force introduction points, the annular decoupling region, the radially elastic material section and the sensor section may be entirely arranged within the same radial cross-section (where the thickness of this cross-section corresponds to the axial extent (range) of the first and second force introduction points, the axial extent of the annular decoupling region, the axial extent of the radially elastic material section and the axial extent of the sensor section), although there may be differences in degree (height) between the individual regions or sections. For example, for stability reasons, the axial extent of the second force introduction point may be greater than the axial extent of the radially elastic material section and / or the sensor section. Such a common radial cross-section offers the advantage of a reduced axial dimension of the torque sensor.

[0010] In a preferred embodiment of the torque sensor according to the invention, the radially elastic material comprises a series of continuous slots extending at least substantially in the circumferential direction and axially through the radially elastic material, i.e. extending axially through the radially elastic material. These at least substantially circumferentially extending slots extend over only a portion of the circumferential extent of the radially elastic material, so that when viewed radially, material connections remain and ensure the mechanical integrity of the torque sensor. The individual substantially circumferentially extending slots may be located at different radial distances from the centre of the body of the torque sensor.

[0011] The circumferential extent of each slot may, for example, range from 25° to 70°, and in a preferred exemplary embodiment is between about 35° to about 55°. The circumferential extent of each slot may be of equal magnitude, but it is equally possible to combine slots of different circumferential extents in a radially elastic material section. For example, if desired, the radial compliance of the radially elastic material section can be increased or decreased in a particular radial direction by appropriately arranging slots of different circumferential extents. The basic principle is that the greater the circumferential extent of a slot, the greater the radial compliance in the area in which such slot is located.

[0012] In one embodiment, the at least substantially circumferentially extending slots are each in the form of a partial circular ring. The circular ring segment shaped slots (shaped like a portion of a circular ring) can be arranged in a number of groups, regardless of the size of their circumferential extent. In one embodiment of the torque sensor according to the invention, the circular ring segment shaped slots are arranged in at least two groups, each group being at a different distance from the center of the body and the circular ring segment shaped slots can have the same or different circumferential extent.

[0013] According to a further development of the above-mentioned embodiment, the circular ring-shaped slots of one group are arranged circumferentially offset (i.e. displaced) with respect to the circular ring-shaped slots of the other groups. According to a further development of such an embodiment, the circular ring-shaped slots of all groups are arranged circumferentially offset with respect to one another. The circumferentially offset arrangement of the circular ring-shaped slots present in the radially elastic material parts with respect to the other circular ring-shaped slots facilitates the production of a torque sensor in which the radially elastic material parts have at least substantially the same radial compliance over their entirety when viewed in the circumferential direction.

[0014] In another preferred embodiment of the torque sensor according to the invention, the at least substantially circumferentially extending slot has a circumferential portion, the radial distance of which from the center of the body is different from the radial distance of the other circumferential portions of the at least substantially circumferentially extending slot from the center of the body. In particular, a slot can have circumferential portions, whereby the radial distance from the center of the body is different. By appropriately selecting the circumferential extent of the individual circumferential portions and the radial distance from the center of the body, the radial compliance (flexibility) of the radially elastic material portions can be adapted as desired and, in particular, can also be made uniform.

[0015] According to yet another preferred embodiment of the torque sensor according to the invention, the radial distance from the centre of the body for at least the substantially circumferentially extending slot varies continuously along the profile of the slot, which in such an embodiment may for example resemble the arrangement of turbine blades of a turbine impeller.

[0016] In a preferred embodiment of the torque sensor according to the invention, regardless of the fine morphology of the slots, at least some of them overlap in the circumferential direction, which makes the radially elastic bending strips structurally simple to manufacture.

[0017] It will be appreciated that many of the above-described embodiments can be combined with one another. Thus, for example, the arrangement of the slots in groups is not dependent on the circular ring segment shape of the slots. Furthermore, the slots can overlap in the circumferential direction regardless of their shape and whether they are arranged in groups. Furthermore, the above-described embodiments can be combined as long as they are not obviously inconsistent.

[0018] Regardless of the embodiment described above, the body of the torque sensor according to the invention is preferably in the form of a circular disk. Deviations from the circular disk shape may be required by special installation situations.

[0019] It is further preferred that the body of the torque sensor according to the invention is unitary, i.e. in one piece, whether the body is circular disc shaped or not. The slots in the radially elastic material may be manufactured, for example, by water jet cutting or laser cutting.

[0020] In a preferred embodiment of the torque sensor according to the invention, a strain gauge is used as measuring transducer, alternatively or in addition, measuring transducers with, for example, fiber Bragg gratings or piezoelectric elements can be used.

[0021] In the following, several exemplary embodiments of the torque sensor according to the invention will be explained in more detail with reference to the accompanying schematic drawings. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a plan view of a first embodiment of a torque sensor according to the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing section II-II of FIG. [Diagram 3] FIG. 1 is a diagram showing a first embodiment in a spatial display (three-dimensional display) from diagonally above. [Figure 4] FIG. 4 is a cutaway view of FIG. 3. [Diagram 5] FIG. 2 is a plan view of a second embodiment of a torque sensor according to the present invention; [Figure 6] FIG. 6 is a cross-sectional view showing the cross section VI-VI of FIG. 5. [Figure 7] FIG. 13 is a diagram showing the second embodiment in a spatial representation seen obliquely from above. [Figure 8] FIG. 8 is a cutaway view of FIG. [Figure 9] FIG. 11 is a plan view of a third embodiment of a torque sensor according to the present invention. [Figure 10] FIG. 10 is a cross-sectional view showing section XX in FIG. [Figure 11] FIG. 13 is a diagram showing the third embodiment in a spatial representation seen obliquely from above. [Figure 12] FIG. 12 is a cutaway view of FIG. [Figure 13] FIG. 11 is a plan view of a fourth embodiment of a torque sensor according to the present invention. [Figure 14] FIG. 14 is a cross-sectional view showing section XIV-XIV of FIG. [Figure 15] FIG. 13 is a diagram showing the fourth embodiment in a spatial representation seen obliquely from above. [Figure 16] FIG. 16 is a cutaway view of FIG. [Figure 17] FIG. 13 is a plan view of a fifth embodiment of a torque sensor according to the present invention. [Figure 18] FIG. 18 is a cross-sectional view showing section XVIII-XVIII of FIG. 17. [Figure 19] FIG. 13 is a diagram showing the fifth embodiment in a spatial representation seen obliquely from above. [Figure 20] FIG. 20 is a cutaway view of FIG. 19. [Figure 21] FIG. 13 is a plan view of a sixth embodiment of a torque sensor according to the present invention. [Figure 22] FIG. 22 is a cross-sectional view showing section XXII-XXII of FIG. 21. [Diagram 23] FIG. 13 is a diagram showing the sixth embodiment in a spatial representation seen obliquely from above. [Figure 24] FIG. 24 is a cutaway view of FIG. 23. [Diagram 25] FIG. 13 is a plan view of a seventh embodiment of a torque sensor according to the present invention. [Figure 26] FIG. 26 is a cross-sectional view showing section XXVI-XXVI of FIG. 25. [Figure 27] FIG. 13 is a diagram showing the seventh embodiment in a spatial representation seen obliquely from above. [Figure 28] FIG. 28 is a cutaway view of FIG. 27. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Figures 1 to 4 show in different views a first embodiment of a torque sensor 10 according to the invention. The torque sensor 10 has a circular disk-shaped body 12 having a central longitudinal axis A (see Figure 2) and a centre M (Figure 1), which is imaginary here. In the centre of the body 12 an opening 14 is provided which can serve for mounting the torque sensor 10 on, for example, an axle or shaft (not shown).

[0024] Around the central opening 14 of the body 12, a number of first force introduction points (here eight first force introduction points) 16 are arranged in a circular configuration, which together form an annular inner flange 18. In the illustrated exemplary embodiment, each first force introduction point is a hole extending axially through the body 12. Radially outwardly of the annular inner flange 18 are mechanically weakened sensor sections 20, which are also annular. The mechanical weakening of the sensor sections 20 is achieved by a series of window holes 22 arranged annularly in the body 12, each of which has the shape of a pie slice in the illustrated embodiment. The window holes 22 with rounded corners pass completely through the body 12 in the axial direction. Between the window holes 22, radially extending measurement spokes 24a and shunt spokes 24b are alternately formed when viewed in the circumferential direction. The measurement spokes 24a are of uniform width and carry measurement transducers 26 (only shown in Figures 1, 5 and 9) configured to generate electrical output signals. For example, the measurement transducers 26 may be strain gauges bonded to the measurement spokes 24a in a known manner. The width of the shunt spokes 24b decreases continuously from the radially inner to the radially outer side.

[0025] Adjacent radially outwardly to the mechanically weak sensor part 20 is a decoupling area 27 of the radially stiff body 12, here in the form of a circular ring. The decoupling area 27 serves to insulate the mechanically weak sensor part 20 against forces that may arise in the radially elastic material part 28 when radially directed forces act on the body 12. The radially elastic material part 28 will be described in more detail below.

[0026] The already mentioned radially elastic material section 28, here also in the shape of a circular ring, is provided radially outside the decoupling region 27 and ensures by its radial compliance that radially directed forces introduced into the body 12 do not falsify the measurement results. An exemplary embodiment of the radially elastic material section 28 is explained in detail below.

[0027] In a first exemplary embodiment shown in Figures 1 to 4, the radially elastic material 28 comprises a series of circumferentially extending slots 30a, 30b. The slots 30a, 30b extend completely axially through the radially elastic material 28, i.e., through the body 12. In the first embodiment, each of the slots 30a, 30b is in the shape of a circular ring segment, and the slots 30a, 30b are arranged in two groups, a first radially inner group of slots 30b and a second radially outer group of slots 30b. The slots 30a of the first radially inner group each have a circumferential extent (extension) of about 55°, whereas the slots 30b of the second radially outer group each have an extent of only about 45°. In other embodiments, the circumferential extent of the slots 30a and 30b can be smaller or larger, and the circumferential extent of the slots 30a, 30b can be the same size. The first group of radially inner slots 30a are all located at the same distance from the center M of the body 12. Similarly, the second group of radially outer slots 30b are all located at the same distance from the center M of the body 12, but this radial distance r2 is slightly greater than the radial distance r1 of the first group of slots 30a. As shown, the first group of slots 30a overlaps the second group of slots 30b when viewed in the circumferential direction, so that each overlapping area forms a radially elastic bending strip 31. Thus, in the first embodiment of the torque sensor 10 shown in Figures 1 to 4, the radially elastic material portion 28 has eight radially elastic bending strips 31, which provide the desired radial elasticity of the radially elastic material portion 28.

[0028] Radially outwardly of the radially elastic material section 28 there is provided an annular outer flange 32 with a number of second force introduction points 34, each in the form of a hole. The second force introduction points 34, like the first force introduction points 16, pass completely through the body 12 in the axial direction. In the illustrated exemplary embodiment, the annular outer flange 32 simultaneously forms the outer periphery of the body 12. However, this does not necessarily have to be the case. Instead, there may be further material areas (not shown) radially outwardly of the annular outer flange 32, depending on the intended application and field of use of the torque sensor 10. To facilitate accurate positioning of the torque sensor 10, a positioning opening 35 is formed in the outer flange 32 at a position between the two second force introduction points 34.

[0029] In all the illustrated embodiments, the body 12 of the torque sensor 10 is in one-piece, i.e. in one-piece form, and has a uniform axial thickness over the entire radial range. However, it is also possible for the body 12 to be in multi-piece form. Whether the body 12 is in multi-piece form or not, it is also possible for the axial thickness of individual parts of the body to differ from that of the other parts. Thus, for example, the area in which the annular outer flange 32 is provided can be designed to have a greater axial thickness than the radially elastic material part 28 and / or the sensor part 20 for stabilization reasons. The same applies to the area of ​​the annular inner flange 18 and / or the decoupling area 27. The body 12 can be made, for example, of aluminum or an aluminum alloy, but also of other materials, for example steel.

[0030] The radially elastic material 28, due to the presence of the radially elastic bending strips 31, has a radial elastic compliance (flexibility) and can therefore act as a radial compensation area, so that tilting moments acting on the torque sensor 10 about the axis A do not adversely affect the measuring spokes 24a on which the measuring transducers are mounted. Furthermore, deformations occurring at the outer flange 32, for example elliptical or arch-shaped deformations, do not adversely affect the measuring spokes 24a and therefore do not lead to a falsification of the output signal generated by the measuring transducer 26. Instead, such elliptical or arch-shaped deformations are effectively absorbed by the radially elastic material 28 and are isolated from the measuring spokes 24a by the decoupling area 31. The elastic bending strip sections 31, on the one hand, provide the desired radial elasticity due to their tendency to be easily deformed in the radial direction, but on the other hand, have a high resistance to deformation in the circumferential direction, so that, despite the presence of the radially elastic material sections 28, the torque sensor 10 has a high stiffness in the circumferential direction, thereby fulfilling excellent requirements for a good introduction and transmission of the torque to be measured to the measuring spokes 24a. This high stiffness in the circumferential direction makes it possible for the torque introduced into the torque sensor 10 to be accurately detected.

[0031] The second embodiment of the torque sensor 10 shown in Figures 5 to 8 differs from the first embodiment shown in Figures 1 to 4 only in the configuration of the radially elastic material portion 28. In the second embodiment, instead of the circular ring-shaped slots 30a and 30b of the first embodiment, there are slots 30c and 30d which also extend at least substantially in the circumferential direction, each slot 30c, 30d having at least one circumferential end 36a, 36b such that the radial distance of the circumferential end 36a, 36b from the center M of the body 12 is different from the radial distance of the other circumferential parts 38a, 38b of the same slot 30c, 30d from the center M of the body 12. As can be clearly seen from Figure 5, each slot 30c has two circumferential ends 36a located relatively radially inward and a central circumferential part 38a connected to the two circumferential ends 36a by a transition area 37, here in the form of a staircase (step), and located radially outward of the circumferential ends 36a. Similarly, each slot 30d has two circumferential ends 36b and a central circumferential portion 38b, where the circumferential ends 36b are located radially outward of the central circumferential portion 38b. As can also be clearly seen from Fig. 5, in the illustrated exemplary embodiment, the circumferential ends 36b of the slots 30d are located at a radial distance from the center M of the body 12 that corresponds to the radial distance from the center M of the body 12 of the central circumferential portion 38a of the slots 30c. In contrast, the central circumferential portion 38b of each slot 30d is located at a radial distance from the center M of the body 12 that is between the radial distances from the center M of the body 12 of the circumferential ends 36a and 36b.

[0032] Furthermore, it can be clearly seen from FIG. 5 that the slots 30c and 30d overlap in the circumferential direction in the region of their circumferential ends 36a and 36b, thereby again forming a total of eight radially elastic bending strip portions 31.

[0033] The advantages of the radially elastic material 28 described with respect to the first embodiment apply to the second embodiment as well.

[0034] 9 to 12 show a third embodiment of the torque sensor 10, which differs from the two previously described embodiments only in the configuration of the radially elastic material sections 28. In contrast to the first two embodiments, the third embodiment does not have two groups of slots 30a, 30b or 30c, 30d, but simply a number of slots 30e of uniform design extending at least substantially in the circumferential direction in accordance with the first two embodiments. Each slot 30e has a circumferential end 36a and a circumferential end 36b which are interconnected by a stepped transition area 37. The circumferential end 36a is located radially inwardly of the circumferential end 36b. In the region of their circumferential ends 36a, 36b, the slots 30e overlap in the circumferential direction, thereby forming a total of 16 elastic bending strip sections 31.

[0035] The advantages of the third embodiment correspond to those of the first two embodiments.

[0036] 13 to 16 show a fourth embodiment of the torque sensor 10, which is generally very similar to the first embodiment. As in the first embodiment, the radially elastic material portion 28 has two groups of circular ring-shaped slots, a radially inner group of slots 30a and a radially outer group of slots 30b. Unlike the first embodiment shown in FIGS. 1 to 4, in the fourth embodiment, the circumferential extent of each of the slots 30a, 30b is smaller than in the first embodiment, and each group has more slots than in the first embodiment. While in the first embodiment, the radially inner group and the radially outer group each contain four slots 30a or 30b, in the fourth embodiment, there are eight slots 30a in the radially inner group and eight slots 30b in the radially outer group. Thus, in the overlapping region of the slots 30a and 30b of the radially elastic material portion 28, a total of 16 radially elastic bending strips 31 are formed.

[0037] Otherwise, the structure of the fourth embodiment corresponds to the first embodiment, and the advantages explained in connection with the first embodiment also apply to the fourth embodiment.

[0038] 17 to 20 show a fifth embodiment of the torque sensor 10, the structure of which differs slightly from the previously described embodiments. In contrast to the previously described embodiments, in the fifth embodiment the annular outer flange 32 with the second force introduction point 34 is arranged in a cross-plane slightly offset with respect to the cross-plane in which the radially stiff decoupling area 27, the mechanically weak sensor part 20 and the annular inner flange 18 with the first force introduction point 16 are arranged. The radially elastic part 28 connecting the annular outer flange 32 to the annular decoupling area 27 starts in the plane of the annular decoupling area 27 and has a first group of circular ring-shaped slots 30f, here consisting of eight slots 30f. Each slot 30f passes completely through the body 12 in the axial direction, as in the previously described embodiments.

[0039] At the outer peripheral edge 40 of the first cross-section, in which the decoupling area 27, the sensor section 20 and the inner flange 18 are located, the radially elastic material section 28 is bent in an L-shape from the first cross-section and establishes a connection with the second cross-section, in which the annular outer flange 32 is located, by means of an axially extending circular ring-shaped peripheral wall 42. The annular outer flange 32 extends radially outward from the circular ring-shaped peripheral wall 42.

[0040] To form the radially elastic bending strips 31, the circular ring-shaped peripheral wall 42 is provided with a second group of circular ring-shaped slots 30g, which here also consists of eight slots 30g. Each slot 30g passes radially through the peripheral wall 42 and is arranged to overlap in the circumferential direction with two slots 30f of the first group. In the illustrated exemplary embodiment, the slots 30g of the peripheral wall 42 are arranged directly below the annular outer flange 32 and above the part of the body 12 that defines the first transverse section. However, it is equally conceivable to move the slots 30g axially closer to the slots 30f, although this would entail a greater expenditure from the point of view of production.

[0041] As a result of the circumferential overlap of the slots 30f and 30g, radially elastic bending strips 31 are formed in the radially elastic material portion 28, more specifically in the circular ring-shaped peripheral wall 42. The number of radially elastic bending strips 31 depends on the number of slots and the number of overlapping regions. In the illustrated exemplary embodiment, the radially elastic material portion 28 has a total of 16 radially elastic bending strips 31 as a result of the eight mutually overlapping slots 30f and 30g.

[0042] From a functionality point of view, the fifth embodiment behaves exactly like the first four embodiments described above.

[0043] 21 to 24 show a sixth embodiment of the torque sensor 10, the structure of which is similar to the fifth embodiment described above. However, unlike the fifth embodiment, the annular outer flange 32 extends radially inwardly from the circular ring-shaped peripheral wall 42, so that the second force introduction point 34 is also located radially inwardly compared to the fifth embodiment, while otherwise the dimensions of the torque sensor remain the same. The structure of the radially elastic material portion 28 corresponds to that of the fifth embodiment.

[0044] 25 to 28 show a seventh embodiment of the torque sensor 10, the structure of which is basically the same as that of the fourth embodiment. The body 12 of the seventh embodiment is disk-shaped and unitary, like the body 12 of the fourth embodiment, but has an octagonal outer shape. Thus, the outer flange 32 is annular, but not circular ring-shaped. This also applies to the shapes of the radially elastic material portion 28 and the radially rigid decoupling region 27.

[0045] The radially elastic material 28 also differs slightly in structure from the previously described embodiments. Consistent with the fourth embodiment, for example, there is a radially inner group of slots and a radially outer group of slots, which in the seventh embodiment is made up of eight radially inner slots 30h and eight radially outer slots 30i, but none of the slots 30h and 30i are in the form of a circular ring piece. Instead, each of the radially inner slots 30h is made up of two straight portions connected to each other at bends, each of which is located on a radial line segment that extends from the corner of the octagon to the center of the body 12. Each of the radially outer slots 30i extends completely straight and does not cross any of the radial lines that extend from the corner of the octagon to the center of the body 12. As shown, the slots 30h and 30i overlap in the circumferential direction, whereby radially elastic bent strips 31 are formed in the overlapping area, here a total of 16 bent strips 31.

[0046] Despite the slightly different shape of the slots 30h, 30i, the function of the radially elastic bending strips 31 formed thereby in the radially elastic material section 28 corresponds to that of the radially elastic bending strips 31 of the embodiment described above, and thus provides the same advantages.

[0047] It will be appreciated that the torque sensor 10 according to the invention is not limited to the embodiment shown and described. Rather, many more configurations of the slots in the radially compliant material 28 are possible that also provide the desired flexibility in the radial direction while at the same time providing high stiffness in the circumferential direction. Thus, for example, in the seventh embodiment, curved slots could be arranged radially outward and straight slots arranged inward, or both the radially inner and radially outer slots could have a curved configuration. Furthermore, the radially compliant material 28 could comprise a series of slots that run like turbine blades in the radially compliant material 28. Many more slot configurations and possible combinations will be obvious to one skilled in the art without departing from the basic concept of the invention.

Claims

1. A torque sensor (10) having an axially and circumferentially extending body (12) from an annular inner flange (18) having a first force introduction point (16), through a mechanically weak sensor part (20) with a measuring transducer for generating an output signal, to an annular outer flange (32) having a second force introduction point (34), said second force introduction point (34) being connected to said sensor part (20) through a radially elastic material part (28), - said radially elastic material portion (28) is formed by a plurality of radially elastic bending strips (31) distributed over the entire circumference of said body (12); - said radially elastic material part (28) is connected to said mechanically weak sensor part (20) via a radially stiff annular decoupling area (27); A torque sensor characterized by:

2. 2. A torque sensor according to claim 1, wherein the bent strip portion (31) is formed by a series of slots (30a, 30b; 30c, 30d; 30e) passing axially or radially through the radially elastic material portion (28).

3. 3. The torque sensor according to claim 2, wherein the slots (30a, 30b; 30c, 30d; 30e) extend at least substantially in the circumferential direction.

4. 4. A torque sensor according to claim 1, wherein at least three bent strips (31) are arranged distributed over the entire circumference of the body (12).

5. 4. The torque sensor according to claim 3, wherein the at least substantially circumferentially extending slots (30a, 30b) each have the shape of a circular ring segment.

6. 6. The torque sensor of claim 5, wherein the circular ring-shaped slots (30a, 30b) are arranged in at least two groups, each group being located at a different radial distance from the center of the body (12).

7. 7. The torque sensor according to claim 6, wherein the circular ring segment shaped slots (30a) of one group are arranged offset in the circumferential direction with respect to the circular ring segment shaped slots (30b) of the other group.

8. 7. The torque sensor according to claim 6, wherein the circular ring-shaped slots (30a, 30b) of all groups are arranged circumferentially offset from one another.

9. 4. The torque sensor according to claim 3, wherein the at least substantially circumferentially extending slots (30c, 30d; 30e) have circumferential portions (36a; 36b) such that the radial distance of the circumferential portions (36a; 36b) from the center (M) of the body (12) is different from the radial distance of other circumferential portions (38a; 38b) of the at least substantially circumferentially extending slots (30c, 30d; 30e) from the center (M) of the body (12).

10. 4. The torque sensor of claim 3, wherein the radial distance from the center (M) of the body (12) of the at least substantially circumferentially extending slot varies continuously along the slot contour.

11. A torque sensor according to any one of claims 2, 3 and 5 to 10, wherein at least some of the slots (30a, 30b; 30c, 30d; 30e) are circumferentially overlapping.

12. The torque sensor according to any one of the preceding claims, wherein the body (12) is circular disc shaped.

13. The torque sensor according to any one of the preceding claims, wherein the body (12) is unitary.

14. A torque sensor according to any one of the preceding claims, wherein the measuring transducer is a strain gauge (26).

15. 15. The torque sensor according to claim 1, wherein the second force introduction point (34), the radially elastic material portion (28), the annular decoupling area (27), the sensor portion (20) and the first force introduction point (16) have a common radial cross section.

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