Tire test bench with a hexapod arrangement and a belt

Abstract

Tire test bench (1) with a frame (5), with a tire holder (7), with a hexapod arrangement (9) with six linear drive elements (21), each of the six linear drive elements (21) being attached with a first end (23) to the frame (5) and a second end (25) to the tire holder (7), wherein a tire (27) with a tread (29) can be attached to the tire holder (7) so as to be rotatable about its axis of rotation (31), with a belt (11) and with two rotatably mounted deflection rollers (13), wherein the deflection rollers (13) are partially wrapped by the belt (11), so that the belt (11) forms a flat belt section (33) between the deflection rollers (13), wherein, when the tire (27) is rotatably mounted on the tire holder (7), the tire (27) can be brought into a contact position by adjusting the linear drive elements (21) of the hexapod arrangement (9) in which the tread (29) of the tire (27) and the flat belt section (33) are in contact, and wherein when the tire (27) and the flat belt section (33) are in contact and the belt (11) is moved relative to the tire (27), the tire (27) rolls on the flat belt section (33).

Description

[0001] The present invention relates to a tire test bench.

[0002] Tire test stands are known from the prior art. These tire test stands typically comprise a frame and a tire holder. A tire with a tread can be mounted on the tire holder so that it can rotate around its axis of rotation. If the tire is mounted on the tire holder so that it can rotate, the tire can be moved into different positions relative to the frame.

[0003] In the tire test stands known from the prior art, a rolling surface unit is provided with a rolling surface that can be moved relative to the frame. The rolling surface of the rolling surface unit can also be referred to as a road substitute and is intended to approximately simulate the conditions on a road. The rolling surface unit can, for example, be formed by a rotatably mounted drum of the tire test stand, and the rolling surface can be formed by a circumferential outer surface of the drum.

[0004] When the tire is rotatably mounted on the tire holder, the tire can be moved into a contact position where the tire tread and the drum's outer peripheral surface are in contact. When the tire and the drum's outer peripheral surface are in contact and the drum's outer peripheral surface is moved relative to the tire, the tire can roll on the outer peripheral surface.

[0005] In general, it is desirable that a tire test bench can be used to particularly accurately simulate the tire's reaction to different tire load conditions and the chassis kinematics when driving on a road.

[0006] It is therefore an object of the present invention to particularly accurately simulate the reaction of the tire to different load conditions of the tire and the chassis kinematics when driving on a road.

[0007] According to the invention, the stated object is achieved by a tire test stand having the features of patent claim 1. The tire test stand has a frame. The tire test stand also has a tire holder. The tire test stand also has a hexapod arrangement with six linear drive elements. Each of the six linear drive elements is attached with a first end to the frame and a second end to the tire holder. A tire with a tread can be attached to the tire holder so that it can rotate about its axis of rotation. The tire test stand also has a belt. The tire test stand also has two rotatably mounted deflection pulleys. The belt partially wraps around the deflection pulleys, so that the belt forms a flat belt section between the deflection pulleys.Then, once the tire is rotatably mounted on the tire holder, the tire can be moved into a contact position by adjusting the linear drive elements of the hexapod assembly. In the contact position, the tire tread and the flat belt section are in contact. Furthermore, when the tire and the flat belt section are in contact and the belt is moved relative to the tire, the tire rolls on the flat belt section.

[0008] The tire test bench has a frame. Various components of the tire test bench can be attached to the frame, such as the first end of each of the six linear drive elements. Other components of the tire test bench that can be attached to the frame include the two rotatably mounted pulleys. Furthermore, an operating element for operating the tire test bench by a tire test bench operator can be attached to the frame of the tire test bench as one of the various components.

[0009] The tire test stand also features a tire holder. A tire can be mounted on the holder so it can rotate around its axis.

[0010] The tire test bench also features a hexapod arrangement with six linear drive elements. In particular, each of the six linear drive elements can be adjusted in length. The hexapod arrangement can be described as parallel kinematics. One advantage of the hexapod arrangement is that, compared to conventional adjustment units designed as serial kinematics, it can exhibit high rigidity while requiring comparatively little space. Furthermore, the hexapod arrangement offers the advantage of high positioning accuracy compared to conventional adjustment units designed as serial kinematics. In particular, the hexapod arrangement allows the tire to be moved into different positions, such as the contact position, with a high degree of precision compared to conventional adjustment units designed as serial kinematics.In connection with the present invention, it has surprisingly been found that the hexapod arrangement, in particular in combination with the flat belt section, can simulate the real chassis kinematics of a vehicle in a test environment better than the tire test benches known from the prior art.

[0011] Each of the six linear drive elements is attached with a first end to the frame and a second end to the tire holder. The six linear drive elements can be described as acting parallel to one another between the frame and the tire holder, so that the hexapod arrangement can be referred to as parallel kinematics. In particular, by adjusting the linear drive elements, the tire holder can be moved relative to the frame and brought into different positions. Preferably, each of the six linear drive elements is pivotally attached to the frame with the first end and pivotally attached to the tire holder with the second end, so that each linear drive element can assume different orientations by adjusting the linear drive elements and pivoting relative to the frame and the tire holder.

[0012] The tire can be mounted on the tire holder with its tread rotatable about its rotational axis. Thus, the tire holder can either have a tire attached to it or not. In particular, because the tire holder can be moved relative to the frame and placed in different positions by adjusting the linear drive elements, a tire attached to the tire holder can be moved relative to the frame and placed in different positions by adjusting the linear drive elements.

[0013] The tire test bench also includes the belt. The belt can also be referred to as an endless belt or strap. The belt is preferably designed to transmit tensile force. In particular, the belt is closed in its longitudinal direction, so that the ends of the belt arranged in the longitudinal direction of the belt are connected to one another or merge into one another.

[0014] The tire test stand also features two pivoting pulleys. The two pulleys can be pivoted on the frame.

[0015] The belt partially wraps around the pulleys, forming a flat belt section between the pulleys. The belt can form a first strand and a second strand. The first strand can be referred to as the working strand and can extend from a first pulley of the pulleys to a second pulley of the pulleys. The second strand can be referred to as the slack strand and can extend from the first pulley of the pulleys to the second pulley of the pulleys. The flat belt section can form a section of the first strand. In the region of the first strand, the belt can move in a straight line in the direction of belt rotation, forming the flat belt section. The flat belt section is flat.The flat belt section preferably extends along a tangential plane on the belt, in which a contact point between the tread and the flat belt section lies when the tire is rotatably mounted on the tire holder and the tread of the tire and the flat belt section are in contact. The flatness of the belt section ensures that the tire can roll on a flat rolling surface. A flat rolling surface formed by the flat belt section is particularly advantageous compared to a rolling surface curved by a circumferential outer surface of the drum, since the flat belt section can simulate a real road, in particular its flat shape, better than tire test stands known from the prior art, in particular those with a rolling surface formed by a circumferential outer surface of a drum.In particular, it was found that the tire's rolling resistance could be significantly reduced when rolling on the flat belt section compared to a curved rolling surface. Furthermore, the combination of belt and pulleys offers a space-saving rolling surface compared to a rolling surface on a drum designed to reduce curvature.

[0016] Then, when the tire is rotatably mounted on the tire holder, the tire can be brought into a contact position by adjusting the linear drive elements of the hexapod arrangement. As already described, a tire attached to the tire holder can be moved relative to the frame and brought into different positions by adjusting the linear drive elements. In particular, the tire can be brought into the contact position by adjusting the linear drive elements of the hexapod arrangement. In the contact position, the tread of the tire and the flat belt section are in contact.Preferably, by adjusting the linear drive elements of the hexapod arrangement, the tire can be moved into further contact positions in addition to the contact position, so that, for example, a camber of the tire, a skew of the tire, a tire load of the tire, in particular perpendicular to the tangential plane on the belt in which the contact point between the tread and the flat belt section lies, and / or the position of the tire relative to the flat belt section, in particular parallel to the tangential plane on the belt in which the contact point between the tread and the flat belt section lies, and perpendicular to the belt rotation direction in the region of the flat belt section and / or parallel to the belt rotation direction in the region of the flat belt section, can be adjusted.

[0017] Furthermore, when the tire and the flat belt section are in contact and the belt is moved relative to the tire, the tire rolls on the flat belt section. Preferably, the flat belt section forms a flat rolling surface on which the tire can roll. As already described, the tire can be moved to other contact positions in addition to the contact position by adjusting the linear drive elements of the hexapod arrangement. If the tire now rolls on the flat belt section, the tire can be moved to different loading states during rolling.For example, when the tire rolls on the flat belt section, the camber of the tire, the skew of the tire, the tire load of the tire, in particular perpendicular to the tangential plane on the belt in which the contact point between the tread and the flat belt section lies, and / or the position of the tire relative to the flat belt section, in particular parallel to the tangential plane on the belt in which the contact point between the tread and the flat belt section lies, and perpendicular to the belt rotation direction in the region of the flat belt section and / or parallel to the belt rotation direction in the region of the flat belt section, can be adjusted.

[0018] In the context of tire test benches, it has been found that a specialist would refrain from using a flat rolling surface from a technical perspective, for example, because the forces acting on the belt due to the different tire load conditions are extremely complex. For example, when the belt is moved, it risks slipping off the pulleys, particularly due to forces acting perpendicular to the belt's direction of rotation, unless technically complex and costly precautions are taken. Therefore, the tire test benches known from the prior art rely on drums with curved rolling surfaces.In the context of the present invention, however, it has been found that the combination of hexapod arrangement and flat belt section justifies the increased technical complexity and increased costs, since this combination can surprisingly simulate the real chassis kinematics when driving on a road particularly well.

[0019] Furthermore, in connection with tire test benches, it has been found that a person skilled in the art would refrain from using a hexapod arrangement from a technical point of view, since the hexapod arrangements known from the prior art, for example due to their symmetrical structure, have low rigidities in directions that are disadvantageous for testing tires that are subjected to different load conditions when rolling, so that when measuring the reaction forces of the tire in response to the different load conditions of the tire, the low rigidity and the disadvantageous deformation of the hexapod arrangement must be taken into account and, for example, calculated out.For example, due to the symmetrical structure of the hexapod arrangements known from the prior art, it is not possible to arrange the linear drive elements in such a way that at least three linear drive elements of the six linear drive elements are arranged in such a way that when a first linear drive element of the three linear drive elements exerts a force on the tire, the largest force component of this force is oriented in the direction of the first spatial direction of the three spatial directions, when a second linear drive element of the three linear drive elements exerts a force on the tire, the largest force component of this force is oriented in the direction of the second spatial direction of the three spatial directions, and when a third linear drive element of the three linear drive elements exerts a force on the tire, the largest force component of this force is oriented in the direction of the third spatial direction of the three spatial directions.Therefore, the tire test benches known from the prior art rely on serial kinematics, in which the directions of force exerted on the tire in all three spatial directions can be realized using comparatively simple technical means at comparatively low cost. However, in the context of the present invention, it has been found that the combination of a hexapod arrangement and a flat belt section justifies the increased technical complexity and increased costs, since this combination can surprisingly simulate the real chassis kinematics during road driving particularly well.

[0020] In connection with the present invention, it has surprisingly been found, when measuring the tire's reaction forces in response to the different loading conditions of the tire, that when the tire rolls on the flat belt section using a hexapod arrangement, the tire's reaction to the different loading conditions through the hexapod arrangement and the flat belt section corresponds better to the reaction of a tire when used on a real road than is the case with tire test benches known from the prior art. In particular, it has been found that the combination of the hexapod arrangement and the flat belt section allows the real chassis kinematics when driving on a road to be simulated particularly well.

[0021] In summary, it can be stated that the tire test bench can particularly well simulate the tire's reaction to different tire load conditions and the chassis kinematics when driving on a road.

[0022] In one embodiment, at least one of the linear drive elements of the hexapod arrangement is designed as a hydraulic cylinder. The design of at least one of the linear drive elements of the hexapod arrangement as a hydraulic cylinder ensures that comparatively high forces can be transmitted. Furthermore, the design of at least one of the linear drive elements of the hexapod arrangement as a hydraulic cylinder ensures uniform and precise adjustment movements. In particular, the design of at least one of the linear drive elements of the hexapod arrangement as a hydraulic cylinder can increase the adjustment accuracy of the hexapod arrangement. Particularly preferably, each of the linear drive elements of the hexapod arrangement is designed as a hydraulic cylinder. The advantages mentioned for the at least one linear drive element apply accordingly to each of the linear drive elements.

[0023] In one embodiment, at least one of the linear drive elements of the hexapod arrangement is designed as an electromechanical linear drive. The design of at least one of the linear drive elements of the hexapod arrangement as an electromechanical linear drive ensures comparatively high setting speeds and high setting accelerations for adjusting the linear drive elements. Furthermore, the design of at least one of the linear drive elements of the hexapod arrangement as an electromechanical linear drive ensures uniform and precise setting movements. In particular, the design of at least one of the linear drive elements of the hexapod arrangement as an electromechanical linear drive can increase the setting accuracy of the hexapod arrangement. Particularly preferably, each of the linear drive elements of the hexapod arrangement is designed as an electromechanical linear drive.The advantages mentioned for the at least one linear drive element apply accordingly to each of the linear drive elements.

[0024] In one embodiment, the tire test bench has a tire drive unit which, when the tire is rotatably mounted on the tire holder, can drive the tire in the direction of tire rotation. With the help of the tire drive unit, the tire can be driven in the direction of tire rotation and thus set into a rotational movement about its axis of rotation. Furthermore, with the help of the tire drive unit, the tire can be accelerated in the direction of tire rotation as it rolls on the flat belt section, so that the tire can be brought into a further load state. In the event that the tire test bench does not have a belt drive unit, the belt can be driven in the direction of tire rotation and contact between the tread and the flat belt section.

[0025] In one embodiment, the tire test bench has a tire braking unit which, when the tire is rotatably mounted on the tire holder, can brake the tire in the direction of tire rotation. Using the tire braking unit, the tire can be braked in the direction of tire rotation, thus slowing down the rotational movement around its axis of rotation. The tire's rotational speed can be reduced in the direction of tire rotation using the tire braking unit. Furthermore, using the tire braking unit, the tire can be braked in the direction of tire rotation while rolling on the flat belt section, allowing the tire to be placed into a further loading state.

[0026] In one embodiment, the tire test bench comprises a belt drive unit that can drive the belt in a belt rotation direction. Using the belt drive unit, the belt can be driven in the belt rotation direction. If the tire test bench does not comprise a tire drive unit, the tire can be driven in the tire rotation direction by driving the belt in the belt rotation direction and contact between the tread and the flat belt portion.

[0027] In one embodiment, the belt drive unit is coupled to a deflection pulley of the deflection pulleys in order to drive the belt via this deflection pulley in the belt's circumferential direction. Coupling the belt drive unit to a deflection pulley of the deflection pulleys in order to drive the belt via this deflection pulley in the belt's circumferential direction provides a technically simple and cost-effective drive of the belt, since additional components for coupling the belt drive unit to the belt can be dispensed with. Preferably, the belt drive unit is coupled to two deflection pulleys of the deflection pulleys in order to drive the belt via these deflection pulleys in the belt's circumferential direction.Coupling the belt drive unit with two deflection pulleys to drive the belt via these deflection pulleys in the belt's direction of rotation ensures that the force is introduced into the belt to drive it at several points and thus the mechanical load on the belt can be reduced.

[0028] Further features, advantages, and possible applications of the present invention will become apparent from the following description of the exemplary embodiments and the figures. All described and / or illustrated features, individually and in any combination, constitute the subject matter of the invention, regardless of their composition in the individual claims or their references. In the figures, the same reference numerals continue to represent the same or similar objects. Fig. 1 shows a schematic view of an embodiment of a tire test bench according to the invention.

[0029] In Fig. 1 is a schematic view of an embodiment of a tire test bench 1 according to the invention. Further shows Fig. 1 an operator 3 of the tire test bench 1.

[0030] The tire test bench 1 comprises a frame 5, a tire holder 7, a hexapod assembly 9, a belt 11, and two pulleys 13. Furthermore, the tire test bench 1 comprises a tire drive unit 15, a tire braking unit 17, and a belt drive unit 19.

[0031] The hexapod assembly 9 has six linear drive elements 21. Each of the six linear drive elements 21 has a first end 23 and a second end 25. Each of the six linear drive elements 21 is attached with the first end 23 to the frame 5 and with the second end 25 to the tire holder 7. A portion of the frame 5 extends into the rear part of the Fig. 1 and is from the Fig. 1 visible section of the frame 5. Three of the six linear drive elements 21 are connected with the first end 23 to the Fig. 1 visible section of the frame 5. Another three of the six linear drive elements 21 are connected with the first end 23 to the Fig. 1 concealed section of the frame 5. Each of the six linear drive elements 21 is enclosed by a bellows to protect the linear drive element 21 from contamination. In the Fig. In the embodiment of the tire test bench 1 according to the invention shown in Figure 1, each of the six linear drive elements 21 of the hexapod arrangement 9 is designed as an electromechanical linear drive. Alternatively, by conversion, each of the six linear drive elements 21 of the hexapod arrangement 9 can also be designed as a hydraulic cylinder.

[0032] Further on, Fig. 1 shows a tire 27 with a tread 29. The tire 27 is mounted on the tire holder 7 so as to be rotatable about its rotation axis 31. The tire drive unit 15 can drive the tire 27, which is rotatably mounted on the tire holder 7, in a tire rotation direction Re. The tire braking unit 17 can brake the tire 27, which is rotatably mounted on the tire holder 7, in the tire rotation direction Re, i.e., reduce the rotational speed of the tire 27 in the tire rotation direction Re.

[0033] As already mentioned, the tire test stand 1 comprises the belt 11 and the two deflection rollers 13. The two deflection rollers 13 are rotatably mounted. The belt 11 partially wraps around the deflection rollers 13, so that the belt 11 forms a flat belt section 33 between the deflection rollers 13. The tire 27, which is rotatably mounted on the tire holder 7, can be brought into a contact position by adjusting the linear drive elements 21 of the hexapod arrangement 9, which Fig. 1 and in which the tread 29 of the tire 27 and the flat belt portion 33 are in contact.

[0034] As already described, the tire test bench 1 has the belt drive unit 19. The belt drive unit 19 can drive the belt 11 in a belt rotation direction Ri. In the Fig. 1, the belt drive unit 19 is provided with the Fig. 1 is coupled to the deflection pulley 13 of the deflection pulleys 13 shown on the left in order to drive the belt 11 via this deflection pulley 13 in the belt rotation direction Ri. Now, when the tire 27 and the flat belt section 33 are in contact and the belt 11 is moved relative to the tire 27, the tire 27 rolls on the flat belt section 33.

[0035] In the Fig.1, the tire 27 can be positioned relative to the flat belt section 33 using the hexapod arrangement 9. In particular, by adjusting the linear drive elements 21 of the hexapod arrangement 9, the tire 27 can be brought into the contact position in which the tread 29 of the tire 27 is in contact with the flat belt section 33. Furthermore, by adjusting the linear drive elements 21 of the hexapod arrangement 9, the tire 27 can be brought into further contact positions in addition to the contact position, in which the tread 29 of the tire 27 is also in contact with the flat belt section 33. If the tire 27 now rolls on the flat belt section 33, the tire 27 is brought into different load states during rolling.By adjusting the linear drive elements 21 as the tire 27 rolls on the flat belt section 33, the camber of the tire 27, the skew of the tire 27, the tire load of the tire 27, and / or the position of the tire 27 relative to the flat belt section 33 can be adjusted. Furthermore, the tire 27 can be driven in the tire rotation direction Re using the tire drive unit 15 or decelerated in the tire rotation direction Re using the tire deceleration unit 17. This allows the tire 27 to be placed in different load states as it rolls.

[0036] In connection with the present invention, it has surprisingly been found, when measuring the reaction forces of the tire 27 in response to the different load conditions of the tire 27, that when the tire 27 rolls on the flat belt section 33 when using the hexapod arrangement 9, the reaction of the tire 27 to the different load conditions through the hexapod arrangement 9 and the flat belt section 33 corresponds better to the reaction of a tire when used on a real road than is the case with tire test benches known from the prior art. In particular, it has been found that the combination of the hexapod arrangement 9 and the flat belt section 33 allows the real chassis kinematics when driving on a road to be simulated particularly well.

[0037] Additionally, it should be noted that "comprising" does not exclude other elements or steps, and "a" or "an" does not exclude a plurality. Furthermore, it should be noted that features described with reference to one of the above embodiments may also be used in combination with other features of other embodiments described above. Reference signs in the claims are not to be considered as limitations. Reference symbol 1 tire test bench 3 operators 5 frames 7 tire holders 9 Hexapod arrangement 11 belts 13 pulley 15 Tire drive unit 17 Tire braking unit 19 Belt drive unit 21 Linear drive element 23 first end of a linear drive element 25 second end of a linear drive element 27 tires 29 Tread 31 axis of rotation 33 flat belt section Re tire rotation direction Ri Belt rotation direction

Claims

[1] Tire test bench (1) with a frame (5), with a tire holder (7), with a hexapod arrangement (9) with six linear drive elements (21), each of the six linear drive elements (21) being attached with a first end (23) to the frame (5) and a second end (25) to the tire holder (7), wherein a tire (27) with a tread (29) can be attached to the tire holder (7) so as to be rotatable about its axis of rotation (31), with a belt (11) and with two rotatably mounted deflection rollers (13), wherein the deflection rollers (13) are partially wrapped by the belt (11), so that the belt (11) forms a flat belt section (33) between the deflection rollers (13), wherein, when the tire (27) is rotatably mounted on the tire holder (7), the tire (27) can be brought into a contact position by adjusting the linear drive elements (21) of the hexapod arrangement (9) in which the tread (29) of the tire (27) and the flat belt section (33) are in contact, and wherein when the tire (27) and the flat belt section (33) are in contact and the belt (11) is moved relative to the tire (27), the tire (27) rolls on the flat belt section (33). [2] Tire test bench (1) according to the preceding claim, wherein at least one of the linear drive elements (21) of the hexapod arrangement (9) is designed as a hydraulic cylinder. [3] Tire test bench (1) according to claim 1, wherein at least one of the linear drive elements (21) of the hexapod arrangement (9) is designed as an electromechanical linear drive. [4] Tire test stand (1) according to one of the preceding claims, wherein the tire test stand has a tire drive unit (15) which, when the tire (27) is rotatably mounted on the tire holder (7), can drive the tire in a tire rotation direction (Re). [5] Tire test stand (1) according to one of the preceding claims, wherein the tire test stand has a tire braking unit (17) which, when the tire (27) is rotatably mounted on the tire holder (7), can brake the tire in a tire rotation direction (Re). [6] Tire test bench (1) according to one of the preceding claims, wherein the tire test bench (1) has a belt drive unit (19) which can drive the belt (11) in a belt rotation direction (Ri). [7] Tire test bench (1) according to claim 6, wherein the belt drive unit (19) is coupled to a deflection pulley (13) of the deflection pulleys (13) in order to drive the belt (11) via this deflection pulley (13) in the belt rotation direction.

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