A TUBE MOTOR

Abstract: A tube motor comprising an electric motor (7) which is placed in a tube (11) and the electric motor (7) is coupled to screw transmission comprising two screws with different pitches and a guide rod (2), whose driven screw (1) and the guide rod (2) are arranged in-line on the common axis and manufactured as single piece, placed in rotatable, axially immovable driven nut (6) and in an immovable guide profile (5) while an electric motor (7), a driving screw (3), a driving nut (4), the guide rod (2) and a guide profile (5) are placed in a tube (11) and the electric motor (7) and the guide profile (5) are fixed to the tube (11) and to the end of the tube (11) is rotatably coupled axially immovable driven nut (6) and to the driven nut (6) is coaxially fixed an output tube (13) and in the ouptut tube (13) is placed the driven screw (1). The pitch of the driven screw (1) is high enough that the screw transmission is self-locking with respect to an external torque. The driven screw (1) and guide rod (2) can be manufactured in single piece so that the twisted part of the guide rod (2) having at least triangular cross section or at least two grooves forms at the same time the driven screw (1).

Description: A Tube motor Technical Field The invention relates to the field of tube motors with velocity reducing screw- and-nut transmission. Background Art Tube motors with screw-and-nut transmission is described for instance in a German Patent DE 3121136. State of the art in tube motors and screw-and-nut transmissions is represented by following patents: GB 857,203, DE1957658, US 2,818,743 a US 4,723,453. Existing tube motors use screw transmission where both guide and driving nuts are manufactured by milling of both axial and helical groove on tube and both guide and driving nuts are coaxial. Disadvantage of such an arrangement is in that it cannot work at high specific torques, related to the cross-section of the transmission. Otherwise are usually used tube motors with planetary gearbox which, however, have the same disadvantage. Disclosure of Invention The present invention avoids mentioned disadvantages of the prior art. The invention is characterized in that a tube motor, including electric motor preferably with hollow axle placed in a tube and coupled to the screw transmission with two screws with different pitches which are placed in two rotatable axially immovable nuts and a guide mechanism, and comprising a driven screw with a guide mechanism arranged coaxially in-line as single piece and placed in rotatable, axially immovable driven nut and in an immovable guide profile while an electric motor, a driving screw, a driving nut, the guide mechanism and a guide profile are placed in a tube while the electric motor and the guide profile are fixed to the tube and to the end of the tube is rotatably coupled axially immovable driven nut and in the driven nut is placed the driven screw. The pitch of the driven screw is high enough that the screw transmission is self-locking with respect to an external torque. Arrangement of the motor and the screw transmission according to the invention enables to maximize the torque of the apparatus with at a given cross-section of the tube motor, because the guide and driven rod, the guide mechanism and the driven nut can be made just fill-in to the cross-section of the tube. The self- locking transmission protects the driving screw and the electric motor againstt external torque. The driven screw and the guide rod can be manufactured of a single piece of the same cross-section e.g. three- to octangular rod and/or of a rod with two- to eight grooves, while the screw can be manufactured on a part of the rod by hot or cold twisting. Manufacturing of driven screws by forming of a part of the guide rod is quick and easy. Use of standard profile rods, especially square, enables to use also standard tools for manufacturing of nuts. It reduces price substantially. The guide mechanism of the driven screw is at least triangular rod placed in the guide profile and/or, for reduction of friction, it is represented by at least two rotatable wheels placed on axles which are fixed at the end of the driving screw perpendicularly to the longitudinal axis of the driven screw, said wheels beeing placed in the guide profile which is manufactured in the tube coaxially with the longitudinal axis of the driven screw. The clutch tin the driven screw enables to compensate misalignment between the driven screw and the guide rod. It enables to increase manufacturing tolerances. Use of driving ball screws substantially increases mechanical efficiency of the apparatus. Use of the electric motor with a hollow axle reduces the design length of the apparatus. Use of the electric motor with gearbox enables to increase transmission ratio of the apparatus. Use of the auxiliary output tube on the driven nut enables easy attachment of driven loads. Brief Description of Drawings Figures schematically show examples only of the arrangement of the tube motor according to the invention. Figure 1. shows arrangement with guide mechanism composed of the square guide rod, with the drivig screw placed in the auxiliary tube and of the guide profile represented by the guide nut. Figure 2 shows arrangement of the apparatus with four-groove guide rod and with ball screw placed in the hollow axle of the electric motor. Figure 3 shows arrangement of the apparatus with square guide rod, with ball screw placed in the hollow axle of the electric motor and with guide mechanism with two rotatable wheels. Examples of Execution of the Invention Example 1 On Figure 1. the tube motor comprises electric motor 7, square guide rod 2, screw transmission with two screws and two nuts with different pitches and the driving screw 3 is placed in the auxiliary tube 8. The driven screw 1 and the guide rod 2 are made of single piece so that the twisted part of the guide rod 2 creates the driven screw 1. The driven screw 1 and the guide rod 2 are of the same cross- section and the driving screw 3 , the driven screw 1 and the guide rod 2 are placed in-line on a common axis and the drivig nut 4, guide profile 5, represented in this case jDy the sliding nut fixed to the tube IJ., and the driven nut 6 are also placed in-line on a common axis. Between the electric motor 7 and the driving screw 3 is placed the gearbox 9. The electric motor 7, driving nut 4, the driving screw 3 , guide mechanism 5, the guide rod 2 and the driven nut 6 are placed in the common tube IJ.. The driving screw 3 is provided by the clutch 12 for compensation of misalignment . The driven nut 6 is fixed to the output tube J3. The apparatus works as follows. The driving screw 3 driven by the electric motor 7 shifts, bv use of the driving nut. 4 the guide rod 2. The driven crew 1 is made on the part of the guide rod 2. As the driven screw 1 moves through the driven nut 6 the linear movement is transformed to the rotational movement. If the external toque is higher than the torque of the motor the self-locking transmission locks the apparatus. Range of rotation is approximately 360° in this arrangement. Example 2 On Figure 2. the tube motor comprises the four-groove guide rod 2 , the ball driving screw 3 placed in the hollow axle 8 of the electric motor 7 and the screw transmission with two screws and two nuts with different pitches. The driven screw 1 and the guide rod 2 are made of single piece so that the twisted part of the guide rod 2 creates the driven screw 1. The driven screw 1_ and the guide rod 2 are of the same cross-section and the driving screw 3 , the driven screw 1 and the guide rod 2 are placed in-line on a common axis and the drivig nut 4, the guide profile 5, and the driven nut 6 are also placed in-line on a common axis. The driven nut 6 is fixed to the output tube |3_. The apparatus works in the same way as the apparatus in example 1. The driving nut 4 driven by the electric motor 7 shifts, by use of the driving screw 3 the guide rod 2. The driven crew 1 is made on the part of the guide rod 2. As the driven screw 1 moves through the driven nut 6 the linear movement is transformed to the rotational movement. Example 3 On Figure 3. the tube motor comprises the guide mechanism including two rotatable wheels J4 e.g. ball bearings placed on the axle JO which is fixed by the end of the driving screw 1 perpendicularly to the longitudinal axis of the driven screw ±, the ball driving screw 3 placed in the hollow axle 8 of the electric motor 7 and the " screw transmission with two screws and two nuts with different pitches. The driven screw 1 and the guide mechanism are made of single piece and the driving screw 3, the guide mechanism and the driven screw 1 are placed in-line on a common axis and the drivig nut 4, the guide profile 5, and the driven nut 6 are also placed in-line on a common axis. The driven nut 6 is fixed to the output tube 13. The guide mechanism of the driven screw 1 is placed in the guide profile 5 which is manufactured and fixed in the tube IJ. coaxially with the longitudinal axis of the driven screw 1. The apparatus works the same way as the apparatus in example 2. The driving nut 4 driven by the electric motor 7 shifts, by use of the driving screw 3 the guide mechanism in the guide profile 5. The guide mechanism is fixed at the end of the driven crew ± . As the driven screw 1 moves through the driven nut 6 the linear movement is transformed to the rotational movement. Preceding description of the arrangement of the tube motor shows only some variants of the apparatus and does not represent all existing variants of the apparatus possible according to the invention. By the tube motor according to the invention it is possible, among other, to interchange the location of the guide nut and rod with driven nut and rod. At least one transmission nut and at least one transmission screw should be made of stainless steel and/or should be provided with sliding film based either on PTFE or on molybdenum disulfide and at least one screw should be provided with trapezoidal thread. Industrial Applicability The tube motor according to the invention is applicable in any equipment where high torque limited range movement is needed e.g. in solar trackers, rotators of antennas, door opening mechanisms etc.

Claims: Claims 1. A tube motor comprising an electric motor, which is placed in a tube and which is coupled to a screw transmission which includes two screws with different pitches which are placed in two rotatable axially immovable nuts and a guide mechanism characterized in that a driven screw (1 ) and guide mechanism of the driven screw (1) represented by a guide rod (2) are arranged in-line on the common axis and it is of single piece and are placed in rotatable axially immovable driven nut (6) and in an immovable guide profile (5) while an electric motor (7), a driving screw (3), a driving nut (4), the guide rod (2) and a guide profile (5) are placed in a tube (11 ) and the electric motor (7) and the guide profile (5) are fixed to the tube (11) and to the end of the tube (11) is rotatably coupled axially immovable driven nut (6) and in the driven nut (6) is placed the driven screw (1 ), while the pitch of the driven screw (1 ) is high enough that the screw transmission is self-locking with respect to an external torque. 2. The tube motor according to claim 1 characterized in that the guide mechanism of the driven screw (1 ) comprises at least two rotatable wheels (14) placed on an axle (10) which is fixed by the end of the driving screw (1) perpedicularly to the longitudinal axis of the driven screw (1 ) and wheels (14) are placed in the guide profile (5). 3. The tube motor according to claim 1 characterized in that the guide mechanism of the driven screw (1 ) is formed by a guide rod (2) of at least triangular cross-section placed in the guide profile (5) and the driven screw (1) is represented by a twisted part of the guide rod (2). 4. The tube motor according to claim 1 characterized in that the guide mechanism of the driven screw (1 ) is represented by guide rod (2) with at least two grooves and placed in the guide profile (5) and the driven screw (1 ) is represented by a twisted part of the guide rod (2). 5. The tube motor according to claims 1 to 4 characterized in that the electric motor (7), the driving nut (4), the driving screw (3), the driven nut (6) and the guide profile (5) are placed in the common tube (11). 6. The tube motor according to claims 1 to 5 characterized in that the driving screw (3) is provided by a clutch (12) between the driving screw (3) and the guide rod (2) 7. The tube motor according to claims 1 to 6 characterized in that the driving screw (3) is a ball screw. 8. The tube motor according to claims 1 to 7 characterized in that the driving screw (3) is placed in the tube (8) and to the tube (8) is fixed the driving nut (4). 9. The tube motor according to claims 1 to 8 characterized in that between the electric motor (7) and the driving screw (3) is placed a gearbox (9). 10.The tube motor according to claims 1 to 9 characterized in that to the driven nut (6) is coaxially fixed the output tube (13).

Inventors: POULEK VLADISLAV, POULEK, VLADISLAV
Applicants: POULEK VLADISLAV, POULEK, VLADISLAV
Application year: 1998
Main classification: F16H25
IPC codes: E05F15, E06B9, F16H25