METHOD AND DRIVE FOR A DEVICE FOR ACCELERATING A GEAR TRAIN DRIVING ON A BLOCK

Description

[0001] The invention relates to a method and a drive for a device for accelerating a gear train of a braking, clamping, or gripping device that moves toward a stop. The device implementing the method has a drive that houses at least one electric motor and at least two gears in a housing. The electric motor has an output member that acts on a lifting carriage via the gears.

[0002] DE 10 2013 020 490 discloses a drive device for a gripping device in which at least one electric motor and several gears are arranged in a housing, with the output acting on a lifting carriage that connects the gripping elements. At least one spring-elastic component is arranged between two of the gears.

[0003] US 4,889,002 A discloses a linear drive in which an electric motor extends and retracts a telescopic rod via a multi-stage gear drive using a helical gear or a spindle / nut drive. The gear drive comprises a secondary shaft whose two gears are coupled to each other in such a way that an angular play is established between them. One gear engages curved slots in the other gear by means of bolts.

[0004] US Pat. No. 5,319,001 A discloses a motor coupling for a cassette changer with angular flexibility. The cassette changer has a pull-out hook that moves back and forth between two stops for hooking and unhooking the cassette to be changed (see US Pat. No. 5,184,260). As soon as the pull-out hook hits one of the stops, the drive motor is shut off by a current-limiting circuit. To form a motor coupling, the shaft ends of the motor and gearbox each have drivers with the cross-section of a circular segment, with the apex of the circular segment lying on the center line of the motor and gearbox shafts. Both circular segments have a central angle of 90 degrees each. During each coupling, the opposing flanks of the two drivers contact each other.

[0005] US 3,559,751 A discloses a motor-driven hammer device with a slider-crank drive. An inner sleeve sits spaced apart in an outer sleeve. A cylinder, closed at both ends, is slidably mounted in the inner sleeve. A floating, air-cushioned piston with a rod protruding from the cylinder is located within the cylinder. When the slider-crank drive is actuated, the inertia and gravity of the piston can cause impact, depending on the engine speed.

[0006] US 4,674,781 A discloses a device for manually and electrically locking and unlocking vehicle doors. During manual opening and closing, a connecting rod is moved relative to a slot in a rack to decouple the motor. After each motor actuation, the rack is moved to a neutral position between the end positions.

[0007] DE 101 14 471 A1 describes an electromechanically actuated vehicle brake. To initiate braking, an electric motor drives a brake mechanism via a clutch with backlash, a multi-stage gear train, and a helical gear. The input and output sides of the clutch each have a stop designed as a claw for rotational drive. Both claws are held at a maximum distance from each other by a spring element when the brake is not applied.

[0008] The present invention is based on the problem of developing a method and a device for accelerating a gear train of a braking, clamping or gripping device traveling on a block, which has a high dynamic response with low energy consumption while providing a high braking, clamping or gripping force, a small installation space requirement and a long service life without a compressed air drive.

[0009] This problem is solved by the features of patent claims 1 and 3. For this purpose, in the method according to patent claim 1, the part of the gear train close to the motor, which consists of the rotating part of a drive motor and the downstream acting on a lifting carriage

[0010] Gearboxes can be accelerated before the part of this gear train remote from the motor. The part of the gear train close to the motor is connected to the part of the gear train remote from the motor via a non-switchable shaft coupling based on a disc coupling and subject to backlash, consisting of a drive pulley and an output pulley, or a thrust coupling with longitudinal backlash. The backlash or longitudinal backlash is fully available during each engagement and release process in order to jerk the stationary gear parts into motion using the already accelerated gear parts. In the case of a shaft coupling with backlash, the coupling elements of the drive pulley and the coupling elements of the output pulley only make contact with each other via flat flanks after a coupling angle of at least 10 degrees during each change of direction of rotation.

[0011] According to patent claim 3, in which the electric motor has an output member that acts on a lifting carriage via the gearing, at least one shaft coupling based on a disk coupling, subject to backlash, or a thrust coupling subject to longitudinal backlash is arranged between the output member of the electric motor and the lifting carriage. The backlash or longitudinal backlash is fully available during each gripping and releasing process, allowing the already accelerated gear parts to jerk the stationary gear parts into motion. The shaft coupling consists of a drive disk and an output disk, with both disks having coupling elements that contact each other via flat flanks during each change of rotation direction only after a coupling angle of at least 10 degrees.

[0012] The drive provided for a device here comprises at least three gears connected in series. The first gear, e.g. an involute-toothed planetary or spur gear, is driven by a highly dynamic brushless DC motor. Its shaft drives, for example, the first gear directly. The gear output of the first gear is also the gear input of the second gear, which in this case is a helical gear whose gear output also represents a lifting carriage. By way of example only, a coupling subject to backlash is located between these gears. After each reversal of direction of rotation of the gear located near the motor in the gear train, this coupling only drives or engages the downstream gear remote from the motor, in this case the helical gear, after a predetermined coupling angle of 10 to 350 degrees.

[0013] In the illustrated example, a double-sliding wedge or double-wedge hook gear is arranged downstream of the helical gear, in which the lifting movement of the lifting carriage is redirected into a braking, clamping, gripping, or releasing movement, tilted by 90 degrees, for example. If the wedge angle of the double-sliding wedge gear is not equal to 45 degrees, a gear increase or decrease takes place in addition to the direction redirection. Instead of the double or multiple-sliding wedge gear, lever gears, slotted gears, eccentric gears, and the like can also be used. Gear combinations are also possible.

[0014] Furthermore, the number of brake, clamping or gripping jaws or slides is not limited to two.

[0015] The invention develops a method and an associated device with the aid of which braking, clamping, or gripping devices that have become jammed during operation can be released automatically. The cause of the device becoming jammed or blocked is of secondary importance. In clamping and gripping devices, jamming occurs, for example, when the corresponding gear trains move against their end stops. Gripping a workpiece that is too large or incorrect can also lead to the gripper jaws becoming jammed. In all cases, the device detects a fault via the position sensors in the gear unit and the speed and position monitoring sensors of the DC motor used in the drive, and reacts to this fault by controlling the motor accordingly.

[0016] In the simplest case, the sensors and the corresponding evaluation are not needed or only partially needed due to the non-switching clutch with backlash or the thrust clutch with longitudinal backlash. With the clutch with backlash, the starting electric motor has the option of initially starting up and gaining momentum with a reduced gear mass moment of inertia and reduced friction during normal operation by utilizing the clutch's backlash. After the backlash has been used up, it abruptly sets other components in motion. With a gripping device, this always occurs during the gripping and release processes. Ultimately, the clutch backlash is always used up when the device's own gripping jaws in the gear train reach their travel end points. This means that it is immediately available again in full for each countermovement.As a result, every time the already accelerating gear parts collide with the still-stationary gear parts, a jolt occurs, in which the inertial mass of the already rotating parts transfers its momentum to the still-stationary parts. This creates a tearing effect on the stationary parts.

[0017] It becomes more complex if this first jerk is not enough to set the entire gear train in motion. This is because the rotational backlash has already been used up due to the initial acceleration in the clutch. In this case, the part of the gear train close to the motor, or even just the rotor of the electric motor alone, must initiate a counter-rotation to restore the rotational backlash. Ideally, the clutch angle is only almost fully utilized in this process. Once the appropriate amount of clutch backlash has been created, the electric motor reverses its direction of rotation again and accelerates again to drive against the still blocked part of the gear train like a sledgehammer. This impact process can be repeated in quick succession, for example, 3 to 15 times, unless the sensor signal evaluation reports that the blockage has been released and aborts this process.

[0018] Further details of the invention emerge from the subclaims and the following description of schematically illustrated embodiments. Figure 1: Perspective view of a parallel gripper; Figure 2: Partial longitudinal section through the double wedge gear of the parallel gripper according to Figure 1 , but with gripping jaws. The right gripping jaw is open; Figure 3: Section through the parallel gripper; Figure 4: Cross-section through the planetary gear of the parallel gripper at the level of the planets; Figure 5: Cross-section through the planetary gear of the parallel gripper at the level of the shaft coupling; Figure 6: Partial section through the parallel gripper after Figure 3; Figure 7: Top view of the parallel gripper without cover; Figure 8: Side view of the parallel gripper, hanging; Figure 9: Perspective view of the gear train near the rotor; Figure 10: Perspective view of the gear train with backlash-affected shaft coupling; Figure 11: Schematic diagram of a backlash-affected shaft coupling, cross section, small angle of rotation; Figure 12: Longitudinal section of Figure 11 ; Figure 13: Schematic diagram of a shaft coupling with backlash, cross section, large angle of rotation; Figure 14: Longitudinal section of Figure 13; Figure 15: Schematic diagram of a thrust coupling with longitudinal play, longitudinal section; Figure 16: Perspective view of the slides, the guide seals and the double wedge from above; Figure 17: Perspective view of the slides, the guide seals and the double wedge from below; Figure 18: Partial cross-section through the guide groove seal transverse to the direction of the guide groove, enlarged; Figure 19: Partial view through the guide groove seal parallel to the direction of the guide groove, enlarged.

[0019] The Figures 1 and 2show a parallel gripping device with two gripping jaws (1, 2), each seated on a slide (100, 101). The slides (100, 101), which are movable in their longitudinal direction, are guided in a guide base body (10) in a guide groove (21), e.g., by sliding bearings. The guide base body (10), which accommodates the guide groove, forms a housing together with a drive base body (280), wherein the drive base body (280) accommodates a drive consisting of an electric motor (221) with, e.g., two downstream mechanical gears (230, 260), cf. Figure 3 The drive acts via a double sliding wedge gear (80) on the slides (100, 101) of the guide base body (10). Figure 1 the gripping device is mounted via its drive base body (280) on a machine or handling device part (6) carrying it.

[0020] The Figure 2represents the upper part of the parallel gripping device in longitudinal section with two screwed-on gripping jaws (1, 2) only theoretically. The gripping jaws are intended to grip a cylindrical workpiece (7), for example. The gripping jaw (1) on the left side of the device rests against the workpiece (7), while the gripping jaw (2) on the right side of the device is shown in the open position. In contrast to the illustration according to Figure 2 Due to the gearing, the gripping jaws (1, 2) always move synchronously towards or away from each other.

[0021] The essentially cuboid-shaped guide body (10) of the parallel gripping device is made, for example, from the aluminum alloy AlMgSi1. The length of the guide body (10) is, for example, twice as long as its width and height. In the exemplary embodiment, the guide body (10) measures, for example, 76 mm in the longitudinal direction—perpendicular to the main center line (3). With this size, the maximum stroke of each slide (100, 101) or gripper jaw (1, 2) is, for example, 6.2 mm. The total height of the housing (10, 280) is, for example, 100 mm.

[0022] The guide base body (10) centrally accommodates the guide groove (21), which is open at the top toward the gripping elements (1, 2). Its rectangular cross-section, for example, measures 17.5 mm wide and approximately 16 mm high. A rail guide groove (26) is machined into each of the flat side walls (23, 24) of the guide groove (21) for later accommodation of a guide rail (31, 32). The rail guide grooves (26) extend over the entire length of the guide base body (10).

[0023] Each guide rail (31, 32) is a substantially trapezoidal rod made of stainless steel, e.g., X90CrMoV18. Due to the high strength of such a guide rail (31, 32), the slides can transmit larger torques to the guide base body (10). Consequently, the gripping device can exert large gripping forces on the workpiece (7) to be picked up.

[0024] Each guide rail (31, 32) has a hexagonal cross-section and has two supporting flanks (33, 34) which are opposite each other in mirror symmetry, cf. Figure 8 , which enclose an angle of 30 degrees. The mirror plane bisects the guide rail (31, 32) along its horizontal longitudinal center plane. The supporting flanks (33, 34) cover at least 75 percent of the guide rail height, with the guide rail height being measured parallel to the center lines of the locating pins (42) positioning the guide rail (31, 32).

[0025] At least one of the guide rails (31, 32) has a transverse groove (36) in the middle, cf. Figure 7 This transverse groove (36) provides additional wear-resistant guidance for the double sliding wedge (81) used in the double sliding wedge gear (80). If necessary, the individual guide rails (31, 32) can also be constructed from two or more consecutively arranged sections.

[0026] In the exemplary embodiment, the guide rails (31, 32) are each fastened to the guide base body (10) with two countersunk screws (41), see. Figure 1 . The guide rails (31, 32) are each positioned on the guide base (10) using two locating pins (42). The locating pins are located between two screw connections.

[0027] In order to achieve a maximum guide play of less than 0.05 mm between the guide rails (31, 32) and the carriages (100, 101), the guide rails can be finely machined by hard metal milling or grinding after installation in the guide base body (10).

[0028] In the underside (13) of the guide base body (10) there is a central, continuous stepped bore (17), the individual steps of which range in diameter from 17 to 34 mm. The first step accommodates an axial thrust ring (271), see Fig. Figure 6The spindle nut (265), mounted between two axial needle bearings (272), rests on this in the second step. The third step of the stepped bore (17) serves to radially support a spindle nut (265) by means of a deep groove ball bearing (255). The fourth and smallest step represents the axial stop for the outer ring of the deep groove ball bearing (255). An axial bearing disk (273) is arranged between the deep groove ball bearing (255) and the upper axial needle bearing (272).

[0029] The stepped bore (17) opens into the guide groove (21). Figure 3 A dowel pin bore (20) is machined to the left of the stepped bore (17) in the vertical central longitudinal plane (8). Two transverse through-bores (16) with cylindrical counterbores are arranged in the long side walls of the guide base (10). These can be used, for example, to attach the device to a handling device (6).

[0030] The cuboid-shaped drive base body (280) is arranged centrally on the underside (13) of the guide base body (10). The centering is provided by a dowel pin (42) located in the dowel pin bore (287) and an axial thrust ring (271) arranged in the stepped bore (17), which simultaneously projects into the central, continuous stepped bore (283) of the drive base body (280). The drive base body (280) has a horizontal cross-section that is at least approximately comparable to that of the guide base body (10).

[0031] The upper part of the stepped bore (283) has only one step, which is visible from the top side (281) of the drive base body (280). This step is the ring gear seat bore (284), in which a ring gear (231), possibly equipped with 56 teeth, is fixedly seated, e.g., pressed or glued. The ring gear (231) of the planetary gear (230) is Figure 6The upper section is bored to create a seat for the deep groove ball bearing (256). The diameter of the bore is larger than the root diameter of the ring gear (231). The axial thrust ring (271), in which the outer ring of the deep groove ball bearing (256) is also supported, also has a similar bore.

[0032] Near the stepped bore (283) there are four through bores (288) with a 90° angular pitch, via which the guide and drive base bodies (10, 280) are connected by means of the screws (68), cf. Figures 4 to 5 . Next to each through-hole (288) there is a vertical fastening hole (289) of larger diameter, by means of which the device is fastened to the machine slide (6) in the embodiment example, cf. Figure 1Except for two diagonally opposite holes, all other mounting holes (15, 16) are provided with countersunk holes suitable for the respective mounting screws. The vertical mounting holes (289) also continue into the guide base body (10).

[0033] The underside (282) of the drive base body (280) has a cover recess (291), see. Figure 1 The cover recess extends from the front to the rear longitudinal side wall of the drive base body (280). A main bore (292) with a depth of 42 mm, for example, projects from the cover recess (291) into the drive base body (280) in the direction of the guide groove (21), see. Figure 3 . The main bore (292) in which the stator (229) of a brushless electric motor (221) is inserted, cf. Figure 5, has a circular cross-section whose diameter corresponds, for example, to 40 percent of the total length of the drive body. The through bore (286), in which the upper roller bearing (224) is located, opens into it (292) from above.

[0034] For example, the electric motor (221) has a rated power of 81 W and a rated speed of 9350 rpm. The torque delivered to its rotor shaft (222) is 0.09 Nm.

[0035] In the after Figure 3 A 21 mm deep recess (293) for accommodating electrical or electronic components is incorporated into the right-hand, narrow side wall. The recess (293) opens into the main bore (292) in the lower area of the drive base (280). The recess (293) can be closed with a rectangular side cover (297), which can be attached to the drive base (280) with four countersunk screws if necessary. The cover (297) carries an electrical connector and a control panel (340).

[0036] The cover (71) that closes the bottom of the drive housing (280) is screwed to the drive base body (280) using four cylinder head screws (68). To accommodate the screw heads of the cylinder head screws (68), the cover (71) has countersunk holes or milled recesses that extend into the area of the longitudinal side walls, see. Figure 1 .

[0037] The cover (71) has a diamond-shaped recess into which a separate bearing block (73) is precisely inserted. The bearing block (73) has a bearing bore (74) for accommodating a roller bearing (223) supporting the rotor shaft (222) at the bottom. It has at least one further recess for supporting various electronic components. Mounted in the recess is, among other things, a circuit board (299) with a combination of an angle sensor and a tachometer (see Fig. Figure 3 .

[0038] The stator (229) of the electric motor (221) is located in the main bore (292). The stator (229) is clamped or glued there, for example. It surrounds the rotor (225), which is non-rotatably mounted on the rotor shaft (222). The upper end of the rotor shaft (222) carries a sun gear (226) of the planetary gear (230), which is formed on it, for example. Below the sun gear (226), whose toothing has, for example, 28 teeth, the seat of the thin-section bearing (224) is located on the rotor shaft (222). The thin-section bearing (224) is axially secured there by means of a retaining ring.

[0039] The sun gear (226) belongs to the planetary gear (230), which is referred to as the first gear, see also Figure 4 It meshes with, for example, four planets (258), each with 14 straight teeth. The planets (258) are mounted, for example, on the web pins (242) of a disk-shaped gear web (235).

[0040] The outer shell of the gear carrier (235) is guided in the deep groove ball bearing (256), which in turn is supported by its inner ring in the ring gear (231). The planets (258) mesh with the stationary ring gear (231). According to the exemplary tooth count of the planetary gear (230), the speed of the sun gear is reduced, so that the gear carrier (235) makes only 0.333 revolutions per sun gear revolution. Depending on the gear design, the reduction ratio is between 1:2 and 1:7. The planetary gear can also be a compound gear or a two-stage gear.

[0041] After Figure 9The gear web (235), as part of a shaft coupling (50), has a non-cylindrical coupling recess (52) in its upper end face. The latter is also shown in Figure 5 in horizontal section. The coupling recess (52) consists of a superposition of a cylindrical bore (57) and two essentially square milled recesses (53). The corners of the square milled recesses (53) remote from the center are rounded. The milled recesses (53) have, in the Figure 5 shown section has an approximately trapezoidal cross-section, wherein the flanks (54, 55) opposite one another in the circumferential direction are planes which intersect at an angle of 30 degrees.

[0042] Coupling elements (62, 63) arranged on the spindle nut (265) engage in this coupling recess (52) with rotational play, making the spindle nut (235) another part of a shaft coupling (50). The coupling elements (62, 63) here represent a beam interrupted by a central bore, the flat, opposing flanks (64, 65) of which lie, for example, in one plane on each side of the beam. Depending on the direction of rotation of the electric motor (221), the coupling elements (62, 63) bear against the flanks (54, 55) on the recess side.

[0043] The Figures 11 and 12show a schematic diagram of such a shaft coupling (50) with backlash, which is based, among other things, on DIN 116 for disc couplings. The shaft coupling (50) consists of a drive disk (51) and an output disk (61). The drive disk (51), which here corresponds to the planetary gear web (235), is generally connected downstream of the drive (220) and, in the exemplary embodiment, has a profiled coupling recess (52) with two stop webs (56) and a centering bore (57). The output disk (61) has a driving beam (62) instead of the coupling recess (52). The latter projects into the coupling recess (52). A centering bolt (67) is located centrally on the driving beam (62) and is guided in the centering bore (57) of the drive disk (51).

[0044] In the Figures 11 and 13the drive pulley (51) is shown in two positions. The first position shows the respective drive pulley (51) before the rotational play has been used up, i.e. before the drive pulley (51) comes into contact with the drive beam (62). Here, the drive pulleys (51) and their hatching are shown in solid lines. The second position shows the respective drive pulley (51) after the rotational play has been used up. The drive pulley (51) now rests on the corresponding drive beam (62). The areas of the pivoted drive pulley (51) that are not congruent with the still unswivelled drive pulley (51) are shown in dashed lines, including their hatching.

[0045] Turns in Figure 11If the drive pulley (51) shown rotates clockwise, it contacts the drive beam (62) via the stop webs (56) after a rotation through a coupling angle (60) of 90 degrees. Before the coupling angle (60) is used up, the part of the gear train remote from the motor, i.e., the driven pulley (61) in this case, does not move.

[0046] The Figures 13 and 14 show a shaft coupling (50) with a particularly large backlash or coupling angle (60). For this purpose, a second stop bar (56) is omitted from the drive pulley (51). On the driven pulley (61), the drive bar (62) protrudes from the centering bolt (67) in only one arm.

[0047] This results in a coupling angle (60) of 270 degrees.

[0048] Due to the asymmetrical design and arrangement of the drive bar (62) and the stop bar (56), appropriate material can be added or removed from the drive and driven disks (51, 61) to prevent static and / or dynamic imbalance. Of course, the drive disk (51) and the driven disk (61) can exchange their geometric shapes, so that the drive disk (51) has the drive bar(s) (56) and the driven disk (61) has the coupling recess (52).

[0049] Alternatively, the Figure 15also only schematically, a thrust coupling (150) subject to longitudinal play, e.g. formed from predominantly rotationally symmetrical parts, for a drive acting in a longitudinal direction. The drive element (151) here is a piston (153) mounted on a piston rod (152). The output element (155) is a cylinder (156) on which an output rod (158) is arranged coaxially. The cylinder (156) has a central piston rod opening (157) on the left-hand side, which surrounds the piston rod (152). Both ends of the cylinder (156) each have, e.g., at least one vent hole (159). The piston (153) and the piston rod (152) are guided in a straight line in the cylinder (156).

[0050] If the drive pushes the combination of piston rod (152) and piston (153) to the right, see. Figure 15, the output element (155) only moves when the piston (153) rests against the cylinder base, which is free of piston rod penetrations. Before this rests, the longitudinal clearance, which depends, among other things, on the cylinder length, is used up.

[0051] The spindle nut (265), cf. Figure 6 , is essentially a tubular turned part with a central threaded bore (268) and an externally formed axial bearing flange (266) approximately centrally. The flat contact surfaces of the axial bearing flange (266), which are oriented perpendicular to the main center line (3), serve as running surfaces for two axial roller bearings (272) clamping it. If necessary, the axial roller bearings (272) can also be replaced by other axial bearing types, which, for example, have balls or tapered rollers as rolling elements. A plain bearing arrangement is also conceivable here.

[0052] After Figure 6The spindle nut (265) has a shaft shoulder above the axial bearing, which forms the seat of the deep groove ball bearing (255). Between the deep groove ball bearing (255) and the upper axial needle bearing (272) is the axial bearing disk (273), which is axially and radially seated in the stepped bore (17). The lower end face of the spindle nut (265) carries the almost cuboid-shaped coupling elements (62, 63) engaging in the coupling recess (52) of the planetary gear carrier (235), see also Figure 5 .

[0053] The axially clamped spindle nut (265) sits on a lifting carriage designed as a threaded spindle (261). The threaded spindle (261), which is integrally formed on the double sliding wedge (81), has a trapezoidal thread (262) DIN 103 TR 8 x 1.5 that fits into the threaded bore (268) of the spindle nut (265). An 8 x 2 trapezoidal thread is also conceivable.

[0054] The double sliding wedge (81), which is arranged in the guide groove (21) as part of a double sliding wedge gear (80), is essentially a square bar-like component with a square cross-section. In its central region, a vertically projecting support web (85, 86) is formed on each side, see Fig. Figures 16 and 17 The support web (85, 86), which extends parallel to the centerline (3) over the entire height of the double sliding wedge, is 2 mm wide. It protrudes 2.4 mm beyond its basic cuboid shape.

[0055] The double sliding wedge (81) has a beveled end face (83, 84) at each of its front ends. The sliding wedge angle is, for example, between 20 and 50 degrees relative to the gripping direction (9). In the illustrated embodiment, it is 50 degrees.

[0056] Parallel to the bevelled end faces (83, 84) there is a keyway (87) between each end face (83, 84) and a support web (85, 86) on each long side of the double sliding wedge (81), cf. Figure 17 The respective keyway (87) is oriented parallel to the nearest end face (83, 84). It has a rectangular cross-section. The double sliding wedge (81) thus has two keyways (87) per long side. Since it is constructed symmetrically to the vertical central longitudinal plane (8), each keyway (87) on a long side is opposite a second keyway. In this way, each end face of the double sliding wedge (81) forms a diagonally arranged T-shaped wedge web (91, 92) when viewed in cross-section.

[0057] Each wedge web (91, 92) of the double sliding wedge (81) engages positively with a slide (100, 101) mounted in the guide groove (21). Each slide is primarily a cuboid-shaped body with slide guide grooves (105) machined into both sides, with which the individual slide (100, 101) is mounted on the guide rails (31, 32).

[0058] The individual slide (100, 101), whose width is e.g. 0.2 mm smaller than the width of the guide groove (21), has in the end face (103) facing the double sliding wedge (81) an obliquely arranged T-groove (106), with which the slide (100, 101) engages the wedge web (91, 92) of the double sliding wedge (81) with a clearance of less than 0.1 mm. Figures 16 and 17Lubrication pockets (109) that can be filled with lubricant are machined into the base of the T-slot (106). On the end face facing away from the double sliding wedge (81), the individual carriage (100, 101) has a bore (115) whose center line lies on the central longitudinal plane (8). A screw (118) that fastens the guide groove seal (300) is inserted into this bore (115). The screw has a circumferential notch in the area of its free end. The tip of a threaded pin (119) that is positioned transversely to the bore (115) projects into this notch in order to place the screw (118) under tensile stress and to fix it together with the sealing body (301, 302), cf. Figure 6 .

[0059] On the upper side (102) of each slide (100, 101) there is a cuboid-shaped, e.g. 3.4 mm high adapter attachment (110) which, when the slide (100, 101) is mounted, protrudes e.g. 1.5 mm - over the top of the housing (12) - from the guide groove (21). At the same time, the adapter attachment (110) protrudes e.g. 1.8 mm over the outer end face facing away from the T-slot (106). The flat upper side (102) of the adapter attachment (110) has two threaded holes equipped with cylindrical countersinks to which the gripper jaws (1, 2) are detachably attached. Centering sleeves are inserted into the cylindrical countersinks for the precise, at least form-fitting positioning of the gripper jaws (1, 2) on the slide (100, 101). If necessary, the gripping jaws (1, 2) are also directly molded or permanently fixed there.

[0060] A stop slot (94) is machined into the underside of each slide (100, 101), Figures 17 and 2 . After Figure 2The locating pin (42) extends into the left-hand stop slot (94). When the slides (100, 101) move apart, the inner end of the stop slot (94) rests against the locating pin (42) to limit the slide stroke.

[0061] The slides (100, 101) are in the guide groove (21), see. Figure 2 , arranged one behind the other in such a way that, with a minimum distance between the gripping jaws, their mutually facing end faces (103) contact or at least almost touch.

[0062] The central area of the guide groove opening (21) is closed with a rectangular cover plate (18). The cover plate (18) is designed to be wide enough so that the two slides (100, 101) just barely touch the gripping jaws (1, 2) when they are in the closed position.

[0063] In order to protect the housing interior (5) and the guide rails (31, 32) from dirt or other wear-promoting contaminants, Figures 16 and 17Angular guide groove seals (300) are placed on the slide (100, 101) and screwed tight. In the illustrated embodiment, the individual guide groove seal (300) surrounds the adapter attachment (110) of the respective slide (100, 101).

[0064] The individual guide groove seal (300) consists of a sealing body (301, 302) for each slide (100, 101). The sealing body (301, 302) is made of thermoplastic elastomer (TPE), which, among other things, has rubber-elastic properties. It has a long leg (333) and a short leg (334). It can be glued to the respective slide (100, 101), at least in part.

[0065] The long leg (333) has a rectangular positioning recess (335) with which it surrounds the gripper jaw mounting base of the respective carriage (100, 101) when assembled. The short leg (334) has a mounting hole (336) approximately in the center and a groove (337) on each side. The mounting hole serves to pass the screw (118) that holds the guide groove seal (300) to the carriage. Each groove (337) surrounds a guide rail (31, 32) with some clearance.

[0066] The elastic sealing body (301, 302) seals the housing interior (5) enclosed by the guide groove (21) along the guide body top side (12) and along the front side (14) from the environment.

[0067] The individual sealing body (301, 302) rests against the guide groove walls (23, 24) and guide groove base with a double-lipped profile (303). The profile (303) has an upper, outer lip (305), which serves as the first barrier against dirt penetrating from the outside in the form of dust and / or moisture. Due to the material's own clamping force, the lip (305) is pushed slightly upwards after installation. A lip (306) of comparable size and geometric dimensions is inclined towards the housing interior (5). Its task, among other things, is to retain the lubricant of the double sliding wedge gear (80) in the housing interior (5). The lip (306) is designed at least almost symmetrically to the upper, outer lip (305), whereby the Figure 18 The axis (307) shown serves as a line of symmetry.

[0068] The two sealing lips (305, 306) enclose a channel-like cavity (308), e.g., at least 0.25 mm deep, which terminates at the inner end face (312) with a V-shaped opening (309). Along the inner end face (312), the outer side (311) of the sealing body (301, 302) has a third sealing lip (324) which slides along the underside of the housing cover (18) when the carriages (100, 101) are moved. The sealing lip (324), see Figure 19, has the shape of a wedge, the front edge (328) of which points in the direction of the base body center line (3).

[0069] During the release and / or gripping stroke, the sealing bodies (301, 302) move back and forth within the guide groove (21) together with the slides (100, 101). During the gripping stroke, the inner sealing lip (306) acts as a wiper, pushing the lubricant forward. During the release stroke, the outer sealing lip (305) acts as a wiper, cleaning the guide rail (31, 32) and the guide groove (21).

[0070] For the closing or gripping movement, the lifting carriage (261), see Figures 3 and 6, which is in its upper end position together with the double sliding wedge (81), is moved downwards from this position by means of the drive (220) consisting of the gears (230, 260) and the electric motor (221). For this purpose, the electric motor (221) is energized. As a result, the clockwise rotating sun gear (226) connected to the rotor shaft (222) drives the planet gears (258). These, in turn, are supported on the stationary ring gear (231), which inevitably causes the web (235) to rotate clockwise around the main center line (3). The web (235), as the drive disk (51) of the coupling (50), initially rotates almost without load, since the driving flanks (54) of the milled recesses (53) have not yet made contact with the corresponding mating flanks (64) of the coupling elements (62, 63). The web (235) only engages the spindle nut (265) when the rotor (225) of the electric motor (221) has already rotated a quarter turn around the main center line (3).Up to this point, only the rotating parts of the part of the gear train close to the motor have moved, these being the rotor shaft (222), the rotor (225), the sun gear (226), the gear web (235) and the four orbiting planets (258), see Figure 9. The joint moment of inertia of the components moving around the main center line (3) is 4.5 kgmm 2< in the exemplary embodiment.

[0071] When the driving flanks (54) of the milled recesses (53) now touch the mating flanks (64) of the coupling elements (62, 63), the 30 degrees of rotational play of the coupling (50) is exhausted. The spindle nut (265) now rotates as the driven disk (61) of the coupling (50). The mass moment of inertia of the entire gear train around the main center line (3) is now, for example, 7.6 kgmm².

[0072] Until the spindle nut (265) was engaged, the mass moment of inertia was more than 40 percent lower, requiring less electrical power for starting. Furthermore, the rolling friction of the roller bearings (255) and (272) does not have to be overcome during this phase. Static and sliding friction in the spindle thread (262, 268) of the helical gear (260) and in the working joints of the double sliding wedge gear (80) are also eliminated.

[0073] By driving the spindle nut (265) belonging to the second gear (260), the threaded spindle (261) or the lifting carriage is set into a lifting motion. The resulting downward movement of the double sliding wedge (81) pulls the carriages (100, 101) inward in the guide groove (21), toward the center. In this process, the lifting carriage (261) plunges deeper into the threaded bore (268) of the spindle nut (265).

[0074] The double sliding wedge (81) is additionally guided in the transverse grooves (36) of the guide rails (31, 32) via its support webs (85, 86). For this purpose, the support webs (85, 86) rest against the side flanks of the transverse grooves (36) with a clearance of less than 0.05 mm. The end faces of the support webs (85, 86) do not contact the respective groove bases of the transverse grooves (36).

[0075] During the closing movement, the wedge surfaces (108) come into contact with the double sliding wedge (81). As soon as the gripping jaws (1, 2) have contacted the workpiece (7), the load on the electric motor (221) increases abruptly due to the gear train moving towards the block. As a result of the gear train and thus also the rotor shaft (222) blocking, the motor current rises above a predetermined limit, which causes the electronic motor control to switch off the motor power. A backward rotating effect caused by the clamping force is eliminated in the second gear (260) because the helical gear (260) is designed to be self-locking at the selected spindle pitch. The helical gear (260) generates a stroke of 1.5 or 2 mm per revolution.

[0076] To release the workpiece (7), the electric motor (221) is energized so that the rotor shaft (222) of the exemplary embodiment begins to rotate counterclockwise. Here, too, the rotor shaft (222), the rotor (225), the sun gear (226), the gear carrier (235), and the four orbiting planets (258) can be accelerated without having to move the helical gear and the double-wedge gear (80). Only after the coupling angle (60) has been used up do the flanks (54) of the coupling recess (53) strike the corresponding counterflanks (64) of the driving elements (62, 63) to set the spindle nut (265) and the downstream movable device parts in motion. Due to the kinetic energy already stored in the rotating parts of the gear train close to the motor during start-up, the spindle nut (265) is set in motion abruptly - without the overcurrent of the motor that was often required previously - as a result of which the gripping jaws (1, 2) are released from the workpiece (7) without any problem.The gear web (235) or the drive pulley (51) acts like a percussion or jackhammer on the spindle nut (265) or the driven pulley (61).

[0077] The upwardly moving double sliding wedge (81) now pushes the slides (100, 101) and the gripping jaws (1, 2) apart via the two gears (230, 260) – while resting against the wedge surfaces (107) – until the end of the stop slot (94) rests against the dowel pin (42). The electric motor (221) is de-energized in the same way as during gripping.

[0078] For simplified handling of the device, an operating panel (340) is arranged on the drive base body (280), see. Figure 1 . After Figure 8 For example, it shows 10 LEDs (351-356) to display certain properties of the parallel gripper used here, as well as three control buttons (341-343).

[0079] The buttons (341-343) are used to teach the parallel gripper how to position the gripping jaws (1, 2) on a specific workpiece (7). To do this, the gripping jaws (1, 2) are moved toward the workpiece (7) by pressing the Forward button (342), e.g., after a targeted reduction of the motor current. The strength of the motor current then serves as a measure of the gripping force. Finally, the gripping position is permanently adopted using the Set button (341).

[0080] The LEDs (353-355) represent the respective gripper position, which is absolutely detected by a Hall sensor (345) located in the drive base body (280). The Hall sensor (345) is located in a recess (285) located in the drive base body (280) next to the deep groove ball bearing (255), see. Figure 6Opposite the Hall sensor (345), a small, disc-shaped permanent magnet (346) is located in a blind hole in the underside of the double sliding wedge (81). It is glued or clamped into place.

[0081] The five LEDs (356), for example, each represent a clamping force, which is indicated in increments between 20 and 100 percent. The upper LED represents a maximum clamping force of 100 percent. Here, too, the clamping force is a function of the motor current during the gripping stroke.

[0082] If the clamping force is to be measured directly in one of the gears, a force sensor can be mounted, for example, on the axial thrust ring (271), which can be used to directly measure the force acting on the spindle nut (265). If necessary, the force sensor is covered with an axial bearing washer for protection.

[0083] The signals provided by the displacement and force sensors are evaluated in the electronics located in the lateral recess (293) and are partly displayed on the control panel (340) by light signals and are also passed on as signals via the plug connection (360) to an external control system.

[0084] As an alternative to the previously described method for opening and closing the respective braking, clamping, or gripping device, it is also possible to query the travel signals of the Hall sensor (345) at short intervals during each motor start-up process in order to check whether, for example, the gripping jaws (1, 2) immediately release from the workpiece upon opening or whether the initial use of the coupling angle (60) is insufficient for this. In the latter case, the electric motor (221) is rotated back in the device's own control system - monitored by at least one sensor arranged on the circuit board (299) - by enough revolutions that the gear web (235) moves back by 75 to 95 percent of the respective coupling angle (60) - in this case by a clockwise rotation. The motor (221) then accelerates again by rotating counterclockwise. If the gripping jaws (1, 2) do not move apart this time either, the described process is repeated up to, for example, ten times in succession.This entire process takes less than three seconds and is only noticeable by a brief vibration of the device. If the gripper jaws (1, 2) still do not release, the motor current is briefly increased and the process starts again.

[0085] This method can also be used to close the gripping jaws (1, 2) if, for example, the device is to hold larger loads (7) for a short time or to generate larger clamping forces. List of reference symbols:

[0086] 1, 2Gripping elements, gripping jaws 3Center line to (10, 280, 221), main center line 5Housing interior, housing interior 6Machine slide, machine part, handling device part 7Workpiece, load 8Vertical center longitudinal plane 9Gripping direction 10Guide body, housing 12Top of body 13Bottom of body 14Front side of the body 15Mounting holes, vertical 16Cross-through holes 17Stepped hole 18Housing cover, cover plate 20Dowel pin hole, vertical 21Guide groove 23, 24Side walls, guide groove walls 26Rail guide groove 31, 32Guide rail, carriage guide rail 33, 34,Supporting flanks 36Cross groove 41Countersunk screws for (31, 32) 42Dowel pins 50Shaft coupling, subject to backlash; gear train part 51Non-switchable drive pulley, see (235) 52Coupling element, coupling recess 53Milled recesses 54, 55Flanks 56Stop webs 57Centering hole, bore 60Coupling angle, backlash angle 61Output disk, see (265) 62, 63Coupling element, driving beam 64, 65Flanks of (62, 63), counterflanks 67Centering bolt 68Socket screws for (10, 280, 71) 71Cover 73Bearing bracket 74Bearing bore 80Double sliding wedge gear 81Double sliding wedge element, double sliding wedge, gear component 83, 84End faces, end faces, inclined 85, 86Support webs 87Keyway 91, 92Key web, T-shaped 94Stop slot 100, 101Slide 102Top 103End face 105Slide guide grooves 106T-slot 107Wedge surfaces, opening system 108Wedge surfaces, closing system 109Lubrication pockets 110Adapter attachment 115Hole for (300) 118Screw for (300) 119Threaded pin with conical tip 150Sliding clutch 151Drive element 152Piston rod 153Piston 155 Output element 156 Cylinder 157 Piston rod opening 158 Output rod 159 Vent holes 220Drive 221Electric motor, brushless 222Rotor shaft, shaft, output member 223Rolling bearing, deep groove ball bearing, bottom 224Rolling bearing, thin-section bearing, top 225Rotor, magnetic body 226Sun gear, toothed component, output member, gear part 229Stator with winding 230Planetary gear, first gear; gear train part 231Ring gear, toothed component, gear part 235Web, disc-shaped; gear part; gear web 242Web pin 255, 256Rolling bearing, deep groove ball bearing; top, bottom 258Planet gears, toothed component, gear part 260Screw gear, second gear; gear train part 261Lifting carriage, threaded spindle, gear link 262Spindle thread, trapezoidal thread, gear link 265Spindle nut 266Axial bearing flange 268Threaded hole 271Thrust ring 272Thrust needle bearing, thrust bearing 273Thrust bearing washer 280Drive body, housing 281Top 282Bottom 283Stepped bore 284Hole for ring gear seat 285Recess for (345) 286Through bore 287Dowel pin bores 288Through bores for screw connection 289Mounting bores 291Cover recess 292Main bore 293Recesses, side 297Side cover 299Board with angle sensor and / or tachometer 300Guide groove seal 301, 302Seal body, elastomer body 303Profile, lateral 304Double lip 305Lip, outer, sealing lip 306Lip, inner, sealing lip 307Axis of symmetry, center line 308Cavity, channel-like 309Opening 311Outside 312End face 324Sealing lip, single lip 325Sealing flank 328Leading edge 333Length leg 334Short leg 335Positioning recess 336Mounting hole 337Grooves 340Control panel 341Set button, central 342Forward button 343Back button 345Hall sensor 346Permanent magnet 351LED for operating status 352LED for fault status 353LED for gripper position: open 354LED for gripper position: closed 355LED for workpiece gripping position 356LEDs for various clamping force settings 360 connector

Claims

1. A method for accelerating a gear train of a braking, clamping or gripping device with initially reduced mass moment of inertia, - wherein, out of the rotating part of a drive motor and the downstream gearings (230, 260) acting on a lifting slide (261), the part of the gear train close to the motor can be accelerated before the part of this gear train remote from the motor, - wherein the part of the gear train close to the motor is connected to the part of the gear train remote from the motor via a non-shiftable shaft coupling (50), which has rotational play, is based on a disc coupling and consists of an input disc (51) and an output disc (61), or via a thrust coupling (150) with longitudinal play, and - wherein the rotational play or the longitudinal play is fully available during every gripping and releasing process in order to set the stationary gearing parts in motion rapidly together with the already accelerated gearing parts, and - wherein, with a shaft coupling (50) with rotational play, on each change of direction, coupling elements (53) of the input disc (51) and coupling elements (62, 63) of the output disc (61) contact one another via flat flanks (54, 55) and (64, 65) only after a coupling angle (60) of at least 10 degrees.

2. The method according to Claim 1, characterised in that with a shaft coupling (50) with rotational play, the rotational play is between 10 and 350 degrees.

3. A drive for a braking, clamping or gripping device in which at least one electric motor (221) and at least two gearings (230, 260) are arranged in a housing (10, 280), wherein the electric motor (221) has an output member (222) that acts on a lifting slide (261) via the gearings (230, 260), - wherein at least one shaft coupling (50), which has rotational play and is based on a disc coupling, or a thrust coupling (150) with longitudinal play is arranged between the output member (222) of the electric motor (221) and the lifting slide (261) in order to set the stationary gearing parts in motion rapidly together with the already accelerated gearing parts, - wherein the rotational play or the longitudinal play is fully available during every gripping and releasing process, and - wherein the shaft coupling (50) consists of an input disc (51) and an output disc (61), wherein both discs (51, 61) have coupling elements (52, 62, 63) that, on each change of direction, contact one another via flat flanks (54, 55) and (64, 65) only after a coupling angle (60) of at least 10 degrees.

4. The drive according to Claim 3, characterised in that a second gearing (260) of two gearings (230, 260) is a helical gearing consisting of a spindle nut (265) and a lifting slide (261) having a spindle thread (262).

5. The drive according to Claim 4, characterised in that the spindle nut (265) as a part of the gear train is a part of the shaft coupling (50) that is a component of the part of the gear train remote from the motor.

6. The drive according to Claim 3, characterised in that a first gearing (230) is a planetary gearing in which the sun gear (226) is arranged on the shaft (222) of the electric motor (221), the planet carrier (235) is part of the coupling (50), and the ring gear (231) is fixed in the housing (10, 280).

7. The drive according to Claim 3, characterised in that the rotating parts of the part of the gear train close to the motor and consisting of the parts (222, 225, 226, 235, 258) have a mass moment of inertia around the main centre line (3) that is less than 60 per cent of the mass moment of inertia of the entire gear train consisting of the parts (222, 225, 226, 235, 258, 266).

8. The drive according to Claim 4, characterised in that the spindle nut (265) is clamped in the housing (10, 280) between two axial bearings (272).