Device and a System for Controlling the Turning of an Object

Abstract

A device and a system for controlling the turning of an object includes a shaft enclosing a first space, and a sleeve forming a second space between the shaft and the sleeve. Movement of the sleeve is transmitted to movement of the object. The device further comprises a housing comprising means for rotating the shaft and at least one inlet for a lubricant, and a lubricant collector. The shaft has a first through hole extending from the first space to the second space, and the sleeve has at least a second through hole for providing the second space in fluid communication with the lubricant collector. The housing is in fluid communication with the second space, and the first space is pressurizeable for causing the lubricant in the second space to be displaced through the second through hole and collected in the lubricant collector.

Claims

1. A device for controlling the turning of an object, said device comprising: a shaft having a hollow cylindrical shape with a central axis and a circumferential wall enclosing a first space; a sleeve having a hollow cylindrical shape with a circumferential wall, said sleeve being arranged so that at least a portion of its circumferential wall encloses said shaft along at least a portion of the axial extension of said shaft forming a second space between said shaft and said sleeve, said sleeve being axially displaceable and rotationally locked in relation to said shaft and axially and rotationally locked in relation to said object to be turned, whereby movement of the sleeve is transmitted to movement of the object; a housing comprising means for rotating the shaft about the central axis, said shaft being axially locked in relation to said housing, said housing further comprising at least one inlet for a lubricant; and a lubricant collector for collecting said lubricant; wherein: said circumferential wall of said shaft has at least a first through hole extending from said first space to said second space, and said circumferential wall of said sleeve has at least a second through hole for providing the second space in fluid communication with the lubricant collector; and said housing is in fluid communication with said second space so that the lubricant can flow from the housing to said second space, and wherein said first space is pressurizeable for causing the lubricant in said second space to be displaced through said second through hole and collected in said lubricant collector.

2. The device according to claim 1, wherein air enters said first space during axial displacement of said sleeve in relation to said shaft in a direction away from said housing.

3. The device according to claim 2, wherein air enters said second space through the first through hole during axial displacement of said sleeve in relation to said shaft in a direction towards said housing causing said lubricant to be pumped out through said second through hole.

4. The device according to claim 3, further comprising means for recirculating the lubricant that is collected in said lubricant collector so that it is returned to said housing through said at least one inlet.

5. The device according to claim 4, wherein said shaft has at least one projection extending radially outwards from the circumferential wall of said shaft, and wherein said sleeve has at least one groove extending radially inwards from the inside of the circumferential wall of said sleeve, said shaft and sleeve being arranged so that said projection is arranged at least partially in said groove.

6. The device according to claim 5, wherein said means for rotating the shaft about the central axis includes a worm wheel in engagement with at least one worm screw so that rotating the at least one worm screw causes said worm wheel to rotate, which causes said shaft to rotate about its central axis.

7. The device according to claim 6, wherein said means for rotating the shaft about the central axis includes at least one actuator.

8. The device according to claim 1, wherein air enters said second space through the first through hole during axial displacement of said sleeve in relation to said shaft in a direction towards said housing causing said lubricant to be pumped out through said second through hole.

9. The device according to claim 1, further comprising means for recirculating the lubricant that is collected in said lubricant collector so that it is returned to said housing through said at least one inlet.

10. The device according to claim 2, further comprising means for recirculating the lubricant that is collected in said lubricant collector so that it is returned to said housing through said at least one inlet.

11. The device according to claim 3, further comprising means for recirculating the lubricant that is collected in said lubricant collector so that it is returned to said housing through said at least one inlet.

12. The device according to claim 1, wherein said shaft has at least one projection extending radially outwards from the circumferential wall of said shaft, and wherein said sleeve has at least one groove extending radially inwards from the inside of the circumferential wall of said sleeve, said shaft and sleeve being arranged so that said projection is arranged at least partially in said groove.

13. The device according to claim 1, wherein said means for rotating the shaft about the central axis includes a worm wheel in engagement with at least one worm screw so that rotating the at least one worm screw causes said worm wheel to rotate, which causes said shaft to rotate about its central axis.

14. The device according to claim 13, wherein said means for rotating the shaft about the central axis includes a friction controlled hub arranged to release said shaft from said worm wheel if the friction between the shaft and the worm wheel reaches above a predetermined threshold.

15. The device according to claim 13, wherein said means for rotating the shaft about the central axis includes at least one actuator.

16. The device according to claim 1, wherein said means for rotating the shaft about the central axis includes at least one actuator.

17. A system comprising the device according to claim 1, said system further comprising: a telescoping cylinder device, comprising: a first cylinder having a cylindrical inner wall; a cylindrical outer wall; and a space between said inner and outer walls; a second cylinder comprising a cylindrical wall which is axially displaceable in said space in response to a pressure exerted by a pressure medium; and a central through hole extending axially through said first and second cylinders; wherein: said shaft is arranged at least partially inside said first cylindrical inner wall; said shaft is axially locked to said first cylinder; and said sleeve is axially locked to said second cylinder so that axial displacement of said second cylinder in relation to said first cylinder causes axial displacement of said sleeve in relation to said shaft.

18. The system according to claim 17, wherein said pressure medium and said lubricant are of the same fluid.

19. A system comprising the device according to claim 6, said system further comprising: a telescoping cylinder device, comprising: a first cylinder having a cylindrical inner wall; a cylindrical outer wall; and a space between said inner and outer walls; a second cylinder comprising a cylindrical wall which is axially displaceable in said space in response to a pressure exerted by a pressure medium; and a central through hole extending axially through said first and second cylinders; wherein: said shaft is arranged at least partially inside said first cylindrical inner wall; said shaft is axially locked to said first cylinder; and said sleeve is axially locked to said second cylinder so that axial displacement of said second cylinder in relation to said first cylinder causes axial displacement of said sleeve in relation to said shaft.

20. The system according to claim 19, wherein said pressure medium and said lubricant are of the same fluid.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] These and other aspects of the invention will now be described in more detail, with reference to the appended drawings illustrating the invention.

[0034] FIG. 1 shows a sectional view of exemplary embodiments of a system according to the second aspect of the invention, comprising a device according to the first aspect of the invention.

[0035] FIG. 2 shows a schematic sectional view of the system illustrated in FIG. 1, in a compressed position.

[0036] FIG. 3 shows a schematic sectional view of the system illustrated in FIG. 1, during expansion of the system.

[0037] FIG. 4 shows a schematic sectional view of the system illustrated in FIG. 1, during compression of the system.

DETAILED DESCRIPTION

[0038] In the following detailed description, embodiments of the invention are described. However, it is to be understood that features of the different embodiments are exchangeable between the embodiments and may be combined in different ways, unless anything else is specifically indicated. Even though in the following description, numerous specific details are set forth to provide a more thorough understanding of the invention, it will be apparent to one skilled in the art that the invention may be practiced without these specific details. In other instances, well known constructions or functions are not described in detail, so as not to obscure the invention.

[0039] FIG. 1 illustrates a sectional view of an exemplary embodiment of a system 1 according to the second aspect of the invention, comprising a device 2 according to the first aspect of the invention. The system further comprises a telescoping cylinder device 3 having a first cylinder 31 having a cylindrical inner wall 311, a cylindrical outer wall 312 and a first cylinder space 313 between the inner and outer walls. The telescoping cylinder device 3 further has a second cylinder 32 having a cylindrical inner wall 321, a cylindrical outer wall 322 and a second cylinder space 323 between the inner and outer walls. The second cylinder 32 is axially displaceable in the first cylinder space 313 in response to a pressure exerted by a pressure medium. The telescoping cylinder device 3 further comprises a third cylinder 33 having a wall 331 which is axially displaceable in the second cylinder space 323 in response to a pressure exerted by the pressure medium. The telescoping cylinder device 3 also comprises a central through hole 35 extending axially through the first, second and third cylinders 31, 32, 33.

[0040] The illustrated exemplary embodiment of a device 2 according to the invention comprises a shaft 21 having a hollow cylindrical shape with a central axis 20 and a circumferential wall 211 enclosing a first space 212. The device further comprises a sleeve 22 having a hollow cylindrical shape with a circumferential wall 221, the sleeve being arranged so that at least a portion of its circumferential wall 221 encloses the shaft 21 along at least a portion of the axial extension of the shaft, forming a second space 222 between the shaft 21 and the sleeve 22. The sleeve 22 is axially displaceable and rotationally locked in relation to the shaft 21, and axially and rotationally locked in relation to the object to be turned 10, whereby movement of the sleeve 22 is transmitted to movement of the object 10. The device 2 further comprises a housing 23 comprising means for rotating the shaft about the central axis 20, the shaft 21 being axially locked in relation to the housing 23. The housing 23 further comprises at least one inlet for a lubricant 232, and the device 2 further comprises a lubricant collector 24 for collecting the lubricant. In the illustrated embodiment, the housing 23 comprises two inlets for a lubricant 232.

[0041] The shaft 21 is arranged at least partially inside the cylindrical inner wall 311 of the first cylinder 31, and the shaft 21 is axially locked to the first cylinder 31. The sleeve 22 is axially locked to the third cylinder 33, so that axial displacement of the third cylinder 33 in relation to the first cylinder 31 causes axial displacement of the sleeve 22 in relation to the shaft 21.

[0042] The circumferential wall of the shaft 211 has at least a first through hole 51, extending from the first space 212 to the second space 222. The circumferential wall of the sleeve 221 has at least a second through hole 52, for providing the second space 222 in fluid communication with the lubricant collector 24. In the illustrated embodiment, there are at least four through holes 51 extending from the first space 212 to the second space 222, and at least two through holes 52 for providing the second space 222 in fluid communication with the lubricant collector 24.

[0043] The housing 23 is in fluid communication with the second space 222, so that the lubricant can flow from the housing 23 to the second space 222. The first space 212 is pressurizeable, for causing the lubricant in the second space 222 to be displaced through the second through hole 52, and collected in said lubricant collector 24. This will be described further in relation to FIG. 2-FIG. 4. From the lubricant collector 24, the lubricant may be led out through at least one opening 241, allowing the lubricant to be recirculated. The opening 241 may lead the lubricant to a tank where it may be filtered and/or reused.

[0044] To achieve rotational locking between the shaft 21 and the sleeve 22, the shaft 21 may have at least one projection (not shown) extending radially outwards from the circumferential wall of the shaft 211, and the sleeve 22 may have at least one groove (not shown) extending radially inwards from the inside of the circumferential wall 221 of the sleeve. The shaft 21 and the sleeve 22 may be arranged so that the projection is arranged at least partially in the groove. Although not shown in the figure, in the illustrated embodiment, the shaft 21 may be a splines shaft, and the sleeve 22 may be a splines sleeve.

[0045] In the illustrated exemplary embodiment, the means for rotating the shaft 21 about the central axis 20 includes a worm wheel 231 in engagement with at least one worm screw 233. In this embodiment, there are two worm screws 233. Rotating the worm screws 233 causes the worm wheel 231 to rotate, which causes the shaft 21 to rotate about its central axis 20. Since the sleeve 22 is rotationally locked to the shaft 21, and the object to be turned 10 is rotationally locked to the sleeve 22, the rotation of the shaft 21 may be transferred to turning of the object 10.

[0046] The means for rotating the shaft 21 about the central axis 20 may also include at least one actuator 234. In the illustrated exemplary embodiment, the device comprises two actuators 234, each of the actuators being connected to one of the worm screws 233 respectively, to allow the actuators to rotate the worm screws. The actuators 234 may for example be hydraulic or electric actuators. Further, the means for rotating the shaft 21 about the central axis 20 may include a friction controlled hub 235, arranged to release the shaft 21 from the worm wheel 231 if the friction between the shaft 21 and the worm wheel 231 reaches above a predetermined threshold. The purpose of this is to prevent the device from being damaged, if the object to be turned 10 gets stuck.

[0047] The illustrated embodiment further comprises a washer 41 arranged to releasably seal the first space 212 from the outside of the device. The function of the washer 41 will be further described in relation to FIG. 2-FIG. 4.

[0048] The exemplary embodiment illustrated in FIG. 1 further comprises a position gauge 43. The position gauge 43 may be arranged in the first space 212, and may comprise a first part 43a and a second part 43b. The first part 43a and the second 43b part may be axially displaceable in relation to each other. For instance, the first part 43a of the position gauge 43 may be axially locked to the housing 23, and the second part 43b may be axially locked to the third cylinder 33. When the position of the system changes, e.g. when the third cylinder 33 is axially displaced in relation to the housing 23, a sensor (not shown) may measure the relative positions of the first part 43a and the second part 43b of the position gauge 43, and the length of the device at the time can thus be determined. The parameter that is measured to determine this may for example be changes in voltage or a magnetic field.

[0049] The device may also comprise an electronic rotation gauge 42. The rotation gauge comprises at least two sensors, and is arranged on the shaft 21. Both of the two sensors are arranged to measure the rotation of the shaft 21, and by extension also the rotation of the object to be turned 10. If the two sensors get different results it is an indication that the object to be turned is stuck. In an application where the object to be turned is a wheel mounted on a vehicle, this may for example correspond to the vehicle driving into something. If this happens, the electronic rotation gauge 42 may send a signal to shut down the actuators 234, to prevent the device from getting damaged. The rotation gauge 42 may also have the possibility to remember the rotational position of the object 10 before it got stuck (e.g. by means of a connected computer or the like), and it may therefore be possible to automatically return the object 10 to this position once it has been released.

[0050] FIG. 1 shows the system in a compressed position. The term “compressed position” means that the second cylinder 32 is axially displaced as far as possible into the first cylinder space 313, and the third cylinder 33 is axially displaced as far as possible into the second cylinder space 323.

[0051] FIG. 2 shows a schematic sectional view of the system illustrated in FIG. 1, also in a compressed position. In this figure it is shown where in the device the lubricant may be present. As previously described, lubricant is entered into the housing 23 through two inlets 232. Preferably, the lubricant is sprayed over the two worm screws 233. In the housing, a lubricant bath 61 is built up. This lubricant bath 61 enables continuous lubrication of the worm screws 233 and the worm wheel 231.

[0052] As previously described, the housing 23 is in fluid communication with the second space 222, so that the lubricant can flow from the lubricant bath 61 in the housing 23 to the second space 222. In embodiments where the shaft 21 is a splines shaft, and the sleeve 22 is a splines sleeve, the lubricant may flow between the splines of the splines shaft and the grooves of the splines sleeve. Here the lubricant serves the purpose of allowing smooth axial displacement between the sleeve 22 and the shaft 21.

[0053] FIG. 3 shows a schematic sectional view of the system illustrated in FIG. 1, during expansion of the system. By expansion of the system is meant that the sleeve 22 is being axially displaced in relation to the shaft 21, in a direction away from the housing 23. This may either be achieved by axially displacing the third cylinder 33 away from the housing 23, or axially displacing both the second cylinder 32 and the third cylinder 33 away from the housing 23. During this axial displacement of the sleeve 22 in relation to the shaft 21, air may enter the first space 212. In the illustrated exemplary embodiment, this is possible due to the washer 41. As the sleeve is being displaced, the washer 41 is also slightly displaced, so that it does not seal the first space 212. As the first space 212 expands during displacement, air enters the first space 212.

[0054] During axial displacement of the sleeve 22 in relation to the shaft 21, in a direction away from the housing 23, the second space 222 also expands. This allows for more lubricant to flow down from the lubricant bath 61 into the second space 222. When the second space 222 is consecutively compressed, lubricant has to be pumped out, to prevent inertia and damage to the device due to an excess amount of lubricant being present in the second space 222. This is further described in relation to FIG. 4.

[0055] In both FIG. 3 and FIG. 4, dashed lines/arrows are used to illustrate air flow, and full lines/arrows are used to illustrate lubricant flow.

[0056] FIG. 4 shows a schematic sectional view of the system illustrated in FIG. 1, during compression of the system. The term “compression of the system” means that the sleeve 22 is being axially displaced in relation to the shaft 21, in a direction towards the housing 23. This may either be achieved by axially displacing the third cylinder 33 towards the housing 23, or axially displacing both the second cylinder 32 and the third cylinder 33 towards the housing 23. During axial displacement of the sleeve 22 in relation to the shaft 21, in a direction towards the housing 23, air may enter the second space 222 through the first through hole 51, causing the lubricant to be pumped out through the second through hole 52. In the illustrated exemplary embodiment, this is possible due to the washer 41. As the sleeve 21 is being displaced towards to housing 23, the washer 41 seals the first space 212 from the outside of the device 2. As the first space 212 is sealed and at the same time is being compressed, the first space 212 is pressurized. As the pressure in the first space 212 increases, air is forced out into the second space 222, through the first through hole 51. This causes an increased pressure in the second space 222, which results in lubricant being forced out through the second through hole 52, and collected in the lubricant collector 24. This flow of the lubricant allows for full lubrication of the second space, i.e. between the shaft 21 and the sleeve 22, no matter the position of the device.

[0057] In exemplary embodiments, the device may further comprise means for recirculating the lubricant that is collected in the lubricant collector 24, so that it is returned to the housing 23 through the at least one inlet 232. This may be achieved through at least one opening 241, which may for example be in fluid communication with a tank and/or a pump. This is however not shown in the illustrated example. The pressure medium which is used for displacing the second cylinder 32 in relation to the first cylinder 31, and the third cylinder 33 in relation to the second cylinder 32, may in some embodiments be of the same fluid as the lubricant. In that case, pressure medium which leaks out from between the cylinders may also be collected in the lubricant collector 24, and recirculated together with the lubricant.

[0058] The person skilled in the art realizes that the invention by no means is limited to the embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For example, the system may comprise only two cylinders, or more than three cylinders. The number of through holes in the sleeve and shaft may be varied, and it is also conceivable that the shaft and sleeve have a different shape than cylindrical.

[0059] In the claims, any reference signs placed between parentheses shall not be construed as limiting to the claim. The word “comprising” does not exclude the presence of other elements or steps than those listed in the claim. The word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements.