Geared motor

Abstract: The geared motor comprising a speed reducer of the worm screw/helical gear type and a speed reducer-driving electric motor, is characterized in that its body consists of two separate pieces (A, B) which are matingly joined and fastened to each other along an ideal vertical plane containing the axis of the motor. Between the extended parts (A', B') of the said pieces the stator (S) of the electric motor is included and firmly clamped, and the said parts are so formed that ducts (45) for cooling air to flow therethrough, are provided around the said stator. The axial shiftment of the speed reducer helical gear (4) is checked by projecting members (21, 121) integrally formed with the two pieces (A, B) constituting the speed reducer body, whereby the assembly and disassembly of the slow speed-operated shaft (2) and of the members which are associated therewith, is thus simplified. When the geared motor is employed for making a capstan device, a box (44) is provided and fastened to the speed reducer body, and contains the terminal board to which the cables for feeding electric current to the electric motor (M), the electric fan (56), and the thermostat controlling the cooling of the motor are connected, by being led through the tubes (48, 148).

Description: The present invention relates to a geared motor, which is particularly adapted for use in a capstan device for lifts or elevators, but which may be used for any like application. The body of the geared motor according to the invention consists of two separate pieces between which also the stator of the electric motor is included and firmly clamped. The said two pieces forming the body are mutually joined like the valves of a shell and are matingly fastened to each other along an ideal vertical place containing the axis of rotation of the electric motor. Document DE-A-2 408 722 discloses a geared motor for use in a capstan device for lifts or elevators, which comprises a speed reducer of the worm screw and worm wheel type, an electric motor for driving the said worm screw, and a fan for supplying cooling air to longitudinal ducts arranged concentrically to the stator of the said electric motor. According to the present invention, it is proposed a geared motor of the above referred type, which further comprises, in combination, the following characterizing features: the speed reducer body is formed by two pieces which are matingly joined to each other along an ideal vertical plane containing the axis of the worm screw, the said pieces being integrally provided with opposed extensions which are also set in mating relation along the said ideal vertical plane and between which the stator of the electric motor is clamped; the longitudinal ducts for the cooling air are formed around the stator, the fan being mounted at the free end side of the said extensions, while grille openings for the outflow of the cooling air are provided in the lateral portions of the opposite end side of said extensions; the two pieces forming the body are provided integrally on their underside with coplanarly arranged connection members to be fastened to any suitable supporting frame. The construction of the geared motor body in two pieces which enclose both the speed reducer and the electric motor ensures the perfect alignment of the axes of the motor and of the speed reducer. Moreover, in consideration of the fact that the body is practically a single body enclosing both the motor and the speed reducer, the flow of the cooling air reaches from the motor also the speed reducer, thus favouring also the cooling of the lubricating oil, while the additional presence of the connection members, which are obtained integrally with the two pieces forming the body, for the fastening of the geared motor to any suitable supporting structure, simplify the construction and setting in place of the geared motor itself. The above and other features of the invention, and the advantages arising therefrom, will appear evident from the following description of one preferred embodiment, made by way of non-limiting example with reference to the attached drawings, in which: Figure 1 is a perspective view of a capstan device incorporating a geared motor according to the invention. Figure 2 is a sectional view of the capstan device according to Figure 1, taken through a vertical plane containing the axis of the speed-reducer-driving electric motor. Figures 3, 4, and 5 respectively are a side elevational view, a front elevational view, and a top plan view of the body of the capstan device according to the invention. Figure 6 is an elevational view showing the capstan device from its front side. Figures 7 and 8 are sectional views of the capstan device body according to Figure 3, respectively taken on lines VII-VII and VIII-VIII, and showing some details of the same. Figure 9 is an elevational sectional view taken on line IX-IX in Figure 4, showing one of the pieces constituting the capstan device body, from its inward side. Figure 10 is a sectional view of the capstan device, taken on line X-X in Figure 2. Figures 11 and 12 are sectional views respectively taken on line XI-XI in Figure 4 and on line XII-XII in Figure 9, and showing further constructional details of the capstan device body. Referring first of all to Figures 1 to 7, there appears that the casptan device body consists of two complementary separate pieces A and B arranged in a mating relation in an ideal vertical plane containing the axis of the high-speed operated shaft of the speed reducer forming part of the capstan device. The pieces A and B are provided at suitably thickened portions thereof with peripheral bores 1 through which the screws for mutually securing the said pieces, are threaded. The surfaces at which the pieces A and B are set in mutual contact, are planed by a tool machine, and a sealing agent, of the silicone type for example, is laid there-over, and these surfaces are then arranged in a mating relation the one against the other, and are mutually secured by means of the said screws threaded through the peripheral bores 1. The pieces A and B are provided under their part that defines the speed reducer body, with bored coplanar ears 100 for attaching the said body to a supporting frame consisting, for example, of a pair of parallel beams 200 which by the ends of their undersides are in turn mutually secured by means of lower crosspieces 300. As shown in Figure 10, the slow-speed operated shaft 2 of the capstan device comprises a greater diameter section 102, on which is fitted the hub 3 carrying the helical gear 4 that is co-axially fixed thereto, the said hub being keyed onto the said shaft by means of a feather 5. At the one side of hub 3 a spacer 6 is provided, and is caused to abut against the inward peripheral edge of the inner ring of bearing 7 which is seated in the housing 8 provided in the piece B of the capstan device body. A ring 9 is caused to bear against the outward peripheral edge of the inner ring of the said bearing 7, and in the inner peripheral edge of ring 9 a housing is formed, in which an annular packing 10 for tightly sealing the shaft 2, is seated. An annular packing 11 of a type on the market, is seated in housing 8, and by its inner peripheral edge is caused to tightly seal the ring 9, whereby to prevent any lubricant outflow. The hub 113 of pulley 13 is caused to bear on the outer peripheral edge of ring 9, the said hub 113 being keyed onto the shaft 2 by means of a feather 14, and being axially locked against the above described members by means of disk 15 and screw 16. At its opposite end, the shaft 2 is rotatably supported by the bearing 17 seated in housing 18, which is formed in the piece A of the capstan device body, and is closed by a cup-shaped member 19 provided with a seal 20. The shaft 2 and the members which are associated therewith, are prevented from being axially shifted by the opposite sides of the helical gear 4 being caused to cooperate with opposed projecting members 21, 121 which are preferably formed of one piece with the inward sides of the pieces A and B of the capstan device body. At the time the surfaces of pieces A and B, to be set in mutual contact, are machined by a tool machine, also the surfaces of the projecting members 21, 121 which are meant for cooperating with the helical gear 4, are accurately machined. The said members 21, 121 have to be set in a mutually spaced apart relation, at such a distance between them that should be slightly greater than the thickness of the said helical gear. Since no thickness results from the sealing agent laid between the surfaces of pieces A and B, by which these pieces are fastened together, it is then possible to assume these surfaces as the intermediate plane of the spacing that must be provided between the machined surfaces of the projecting members 21, 121. If the thickness of the helical gear 4 is known, the required surface-machining of the projecting members 21, 121 can be easily carried out. As seen in Figures 7, 9 and 10, the projecting members 21, 121 are caused to act upon the sides of that portion of the helical gear 4 which comes to be in mesh with the driving screw 25 (see hereinafter). In order to ensure that the surfaces of the projecting members 21, 121 which contact the helical gear 4, be sufficiently lubricated even with the geared motor being intermittently operated, a recess 400 is formed in the uppermost region of each projecting member 21, 121 (see Figure 9). The said recesses are closed by the helical gear 4, and some lubricating oil being transferred by the helical gear, is collected therein. When the geared motor is stopped, the oil contained in the recesses 400 slowly leaks out on the periphery of the helical gear 4, which is thus suitably lubricated at the time the geared motor will be subsequently re-actuated. It is apparent that by the disclosed embodiment the assembly and disassembly of the slow speed-operated shaft 2 and of the members being associated therewith, is considerably simplified. The housings 8 and 18 for the bearings (7, 17) rotatably supporting the shaft 2, may be even not formed at their inward sides with their abutment end members 108 and 118, in that it is the very shaft 2 that prevents the bearings from being undesirably displaced axially. In Figure 10, reference numeral 22 denotes the plug for closing the port for admitting lubricating oil into the capstan device body, and reference numeral 23 denotes the plug for closing the minimum lubricant level port. In Figure 2 there is shown that the high-speed operated shaft 24 of the capstan device comprises in its intermediate section a worm screw 25 which is caused to cooperate with the above disclosed helical gear 4. In the pieces A and B of the capstan device body two axially aligned housings- are defined, in which the bushings 26, 126 of a low friction material are seated, and rotatably support the said high-speed operated shaft 24. Referring also to Figures 8 and 9, there appears that the housings in which the said bushings are seated, have their intermediate portion formed with a respective annular recess 27, 127 which is set in communication with the interior of the speed reducer body, through a respective aperture 28, 128 in which one side end of small gutter-like members 29, 129 is respectively fitted, and is attached to the relative inward side of the said pieces A and B (see Figure 10), the said gutter-like members being provided for collecting the lubricant being transferred by a splashing action from the worm screw/helical gear unit into the said members, and for causing the lubricant to flow by gravity into the said recesses 27, 127. The bushings 26, 126 are formed with downward bores 30, 130 for allowing the lubricant to flow to the so-called scores provided in the inner surfaces of the said bushings, whereby the required lubrication is ensured of the bushing surfaces which are set in contact with shaft 24. Still in Figure 2 there is shown that the housings in which the bushings 26, 126 are seated, are respectively formed at their outward end section with a greater diameter portion, in which: at the side that is turned toward the electric motor, a cup-shaped member 31 is housed, which is provided with seals 32 and 33 respectively received in the peripheral outer edge of its greater diameter portion and in the peripheral inner edge of its smaller diameter portion. at the opposite side a cup-shaped member 131 is housed, which is secured by means of screws 34 (see also Figure 6) and is caused to surround the outer ring of a pair of thrust bearings 35 with their inner ring being axially locked by a locking nut 12 to a tapered section of shaft 24. Reference numeral 36 denotes an elastic compensator which is caused to act upon the said bearings, and reference numeral 37 denotes the seals provided in the cup-shaped member 131, and acting upon the shaft 24. A flywheel 38 is keyed onto that end of shaft 24 which lies outside of the cup-shaped member 131, and the said fly-wheel conventionally carries a drum 138 that is acted upon by a brake means comprising a pair of jaw-like members 39, 139 (see also Figures 6 and 10), which by their lower ends are pivotally connected at 40, 140 to a respective support provided in the pieces A and B of the geared motor body, the said jaw-like members being intermediately provided with braking shoes 41, 141, and being connected by their upper ends to the respective spring 42, 142 for engaging the said brake means, and to the respective electromagnet 43, 143 for releasing the same. According to a preferred embodiment of the invention, the electromagnets 43, 143 are fitted on a box 44 (see Figure 2), which is secured to the body of the speed reducer. The terminal board for the electric circuit to the stator of the electric motor M that is associated with the said speed reducer, and the terminal board for the electric fan for cooling the motor, are placed inside the said box, as will be disclosed later on. As shown in detail in Figure 7, the pieces A and B constituting the body of the capstan device speed reducer, are formed with opposed extended parts A' and B' which are also set in mating relation with each other in the same ideal vertical plane containing the said pieces A, B, and which are characterized by being caused to include and firmly clamp the stator S of the electric motor that drives the said capstan device, the end side of the said stator which is opposite to the speed reducer, being however left in an exposed condition. Still in Figure 7 there is shown that the inward sides of the extended parts A' and B' are formed with a succession of substantially concave portions; more particularly, the said concave portions are so formed that longitudinal ducts 45 are provided all around the stator, for the cooling air that is circulated by the electric fan as disclosed hereinafter, to flow therethrough and then thereout to the ambient atmosphere through the outlets 46 laterally provided in the extended parts A' and B' (see Figures 3, 5, and 9), the said outlets being each closed by a safety grille 47 (Figure 1). The electric cables for feeding the electric fan are also led through one of the said ducts 45, and together with the electric cables of the circuit to the stator of motor M, the former cables are led into the box 44, through bores provided in the closed end side of the extended parts A', B', and through cable-holding tubes 48, 148 (see Figures 1 and 2). In Figures 1, 2, 3, and 9, numeral 49 denotes an eye formed of one piece with the intermediate upper portion of at least one of the pieces A, A' and B, B' constituting the capstan device body. The rotor R of the electric motor M is shrinked on a suitably tapered section of shaft 24, as shown in Figure 2. A small pulley 50 is keyed onto that end of shaft 24 which protrudes from the rotor R, and by means of belts 51 the said pulley is connected to a speedometer dynamo 52 which by its own brackets is fixed in bores 53 suitably provided in the areas in which the extended parts A' and B' are fastened together. A collar 54 is fitted on the free end of parts A' and B', and a crosspiece 55 is diametrically attached thereon, and supports the electric fan 56 being arranged in a coaxial relation with shaft 24, and being protected by a bell 57 which is provided with a grid-like screen at its end side, and is secured by means of screws to the said collar 54. The electric fan is automatically controlled by a not shown thermostat that detects the temperature of the stator of the electric motor, the whole in such a manner that is conceivable and easily practicable by those skilled in the art. From the drawings to which reference is made, there appears that the pieces A, A' and B, B' are suitably formed with inner and outer ribs for mechanically strengthening and also for increasing the surface of said pieces which is in contact with air, and is cooled thereby.

Claims: A geared motor particularly adapted for use in a capstan device for lifts or elevators, comprising a speed reducer of the worm screw (25) and worm wheel (4) type, an electric motor for driving the said worm screw, and a fan (56) for supplying cooling air to longitudinal ducts (45) arranged concentrically to the stator (S) of the said electric motor characterized in that the speed reducer body is formed by two pieces (A, B) which are matingly joined to each other along an ideal vertical plane containing the axis of the worm screw (25), the said pieces being integrally provided with opposed extensions (A', B') which are also set in mating relation along the said ideal vertical plane and between which the stator (S) of the electric motor is clamped; the said longitudinal ducts (45) are formed around the said stator (S), the said fan (56) being mounted at the free end side of the said extensions (A',B'), while grille openings (46, 47) for the outflow of the cooling air are provided in the lateral portions of the opposite end side of said extensions; the said pieces (A, B) forming the body are provided integrally on their underside with coplanarly arranged connection members (100) to be fastened to any suitable supporting frame (200, 300). The geared motor according to claim 1, characterized in that the fan (56) is controlled by at least one thermostat that detects the temperature of the stator (S) of the electric motor (M) driving the speed reducer. The geared motor according to Claim 1, characterized in that when the geared motor is used in a capstan device, the electric cables for feeding the electric motor, and the electric cables connected to the thermostat/motor-cooling electric fan unit, are led out through bores in the upper portion of the closed end side of both of the extended parts (A', B') between which also the stator of the said electric motor is clamped, and are sheathed in tubes (48, 148) being caused to abut against a box (44) which is arranged in a fixed position on the top of the speed reducer body (A, B), and which preferably performs the function of support for the electromagnets (43, 143) that actuate the normally engaged brake means being caused to act upon the flywheel (38) keyed onto the high speed-operated shaft (24) which is fitted with the worm screw (25), and on which the rotor (R) of the said electric motor is preferably shrinked, the terminal boards for the said electromagnets, the electric motor, and the relative fittings to be fed with electric current, being housed in the said box (44). The geared motor according to Claim 1, characterized in that the two pieces (A, B) forming the body of the speed reducer, have their inward sides formed with preferably opposed projecting members (21, 121) of one piece therewith or inserted, which are properly planed relative to the edges of the said pieces, by which these pieces are matingly joined and fastened to each other, in such a manner that the helichelical gear being preferably axially locked to the slow-speed operated shaft (2) of the speed reducer, whereby the said shaft can be assembled even without the provision of axially retaining means, and the assembly and disassembly of this shaft and of the members being associated therewith, is thus simplified. The geared motor according to Claim 4, characterized in that the said opposed projecting members (21, 121) which are each caused to cooperate with the respective side of that portion of the helical gear (4) which comes to be in mesh with the relative worm screw (25), are each formed in their uppermost portion with a respective recess (400) for collection of the lubricating oil being transferred thereinto by the helical gear which closes the said recesses, this in order to ensure a sufficient lubrication of the said helical gear even when the same is again set in operation after a long time of rest. The geared motor according to Claim 4, characterized in that the hub (3) of the helical gear (4) is keyed onto the slow speed-operated shaft (2) of the speed reducer, and by one of its peripheral edges this hub is held in an abutting relation with a step formed in the said shaft, by a spacer (6) which is caused to bear against the inward peripheral edge of the inner ring of one (the 7) of the bearings supporting the said slow speed-operated shaft, the said inner ring being in turn caused to bear by its outward peripheral edge against a ring (9) which is fitted with an annular packing (10) for tightly sealing the shaft (2), and is sealed by an annular packing (11) provided in the housing (8) in which the said bearing (7) is seated, and the hub (113) of the drawing pulley (13) in the capstan device is caused to bear against the outer peripheral edge of said ring (9), the said hub being keyed onto the slow speed-operated shaft (2) and being axially held thereon by an external disk (15) and by an axially threaded hub-locking screw (16). The geared motor according to Claim 1, characterized in that the worm screw (25) is formed of one piece with the shaft (24) onto which the rotor of the electric motor is keyed, the said shaft being rotatably supported by a pair of bushings (26, 126) made of a low friction material, which are lubricated by gravity through gutter-like members (29, 129) into which some of the lubricant being transferred by a splashing action from the worm/screw/helical gear unit, is caused to flow, and which will deliver the oil having been collected therein, into the annular recesses (27, 127) encompassing the said bushings, which in turn are provided with bores (30, 130) for conveying oil into the scores formed in the bushing inner surfaces by which the said bushings are caused to cooperate with the said shaft, and this shaft is provided at its end on which the flywheel (38) is fitted, with a pair of thrust bearings (35) which are enclosed in a cup-shaped member (131) which by means of screws is secured to the speed reducer body (A, B).

Inventors: BIANCIARDI ETTORE, AULANKO, ESKO, BIANCIARDI, ETTORE, SARANSAARI, PERTTI, VENHO, OLA
Applicants: SABIEM SRL, SABIEM S.P.A.
Application year: 1991
Main classification: B66B11
IPC codes: F16H57, B66B11, H02K7