Output group with planetary roller gear

Abstract

The invention relates to an output assembly with a planetary roller gear unit comprising an input shaft rotatably mounted in a drive housing and two gear nuts. The gear nuts are mounted to be rotationally fixed relative to the drive housing and displaceable in the translational direction. The drive housing or a gear spindle forms an output body of the output assembly. The output body is mounted to be rotationally fixed in the drive housing and is guided in the translational directions of movement within the drive housing. A rechargeable potential energy storage device is arranged in the power flow between each gear nut and the drive housing. When the output body is locked, the gear nut and the drive housing are brought closer together by rotation of the input shaft, charging the potential energy storage device associated with one of these gear nuts.This storage of potential energy supplies kinetic energy to an energy sink, at least temporarily. The present invention develops a drive unit with which a breakaway impulse can be applied in two drive directions.

Description

[0001] The invention relates to an output group with a planetary roller gear, which has an input shaft rotatably mounted in a drive housing and two gear nuts.

[0002] From DE 10 2017 124 386 A1, a planetary roller gear with a rotaryally driven gear housing in which two gear nuts are rotaryally mounted in rolling bearings is known. A threaded spindle is movable in the translational direction by means of the planetary roller gear.

[0003] The present invention is based on the problem of developing a drive unit with which a breakaway impulse can be applied in two drive directions.

[0004] This problem is solved by the features of the main claim. For this purpose, the gear nuts are mounted so as to be rotationally fixed relative to a gear housing and displaceable in the translational direction. The gear housing or a gear spindle forms an output body of the output assembly. The output body is mounted in the drive housing in a rotationally fixed manner and is guided in the translational directions of movement within the drive housing. A repeatedly chargeable and dischargeable potential energy storage device is arranged in the power flow between each gear nut and the gear housing. When the output body is locked, an approach of the gear nut and the gear housing relative to each other, caused by a rotation of the input shaft, charges the potential energy storage device associated with one of these gear nuts, which is located in the power flow. This potential energy storage device supplies kinetic energy to an energy sink, at least temporarily.

[0005] The drive unit has a rotatable input shaft, which is part of a planetary gear system. This non-self-locking planetary gear system, which can be driven in both directions of rotation, converts the input motion into a translational motion of the gear nuts. Each gear nut is associated with a potential energy storage device in the power flow. Energy is transferred to the output element via this potential energy storage device, such as a spring energy storage device, a pressure storage device, a nitrogen-filled gas spring, stored deformation energy, a lifting device, etc. In this case, the output element forms an energy sink, at least temporarily.

[0006] If the movement of the driven element is impeded, for example by a brake, a clamp, or a load acting against the direction of movement of the driven element, the potential energy storage is charged. For example, a spring energy storage device is compressed. If the input shaft rotates in the opposite direction, the impedance of the driven element can be released. The energy released from the potential energy storage device to the driven element can then be used as a breakaway impulse in addition to the drive energy.

[0007] Further details of the invention will become apparent from the dependent claims and the following description of schematically illustrated embodiments. Fig. 1: Gripper; Fig. 2: Cut of the Fig. 1; Fig. 3: Isometric section of the Fig. 1 with a cutting plane normal to the cutting plane of the Fig. 2; Fig. 4: Bottom view of the Fig. 1; Fig. 5: Drive motor, freewheel and input shaft; Fig. 6: Free run; Fig. 7: Cross-section of Fig. 7; Fig. 8: Ride-along ring; Fig. 9: Inner star; Fig. 10: Freewheel position; Fig. 11: Blocking position; Fig. 12: Planetary roller gear; Fig. 13: Cut of the Fig. 10; Fig. 14: Gear spindle; Fig. 15: Planetary role; Fig. 16: Gear nut; Fig. 17: Spindle housing; Fig. 18: Variant of the drive module; Fig. 19: Drive module with torsional compensation element.

[0008] The Fig. Figures 1-17 show a gripper (10) in the form of an electric gripper (10) in views, sections, and some individual parts. The gripper (10) has a drive module (20), a tool module (190), and an electronics module (200). The drive module (20) has a drive housing (21) in which a drive unit (22) is arranged. The tool module (190) has a tool housing (191) in which a tool unit (192) is arranged. The electronics module (200) has an electronics housing (201) in which an electronics unit (202) is arranged. The drive housing (21), the tool housing (191), and the electronics housing (201) are connected to each other, for example, by screws. Together they form a gripper housing (11). Plug connectors, for example, are provided for the electrical connections between the individual modules (20, 190, 200).

[0009] Inside the gripper housing (11), the drive unit (22) drives the tool unit (192). The electronic unit (202) controls this process. The electronic unit (202) has internal computing and storage modules. It also features data, signal, and power interfaces for communication with higher-level controllers.

[0010] In this embodiment, the tool module (190) is designed as a parallel gripping unit. It has two gripper slides (193) that are guided in a common guide groove (194) of the tool housing (191). A gripper element can be attached to each of the gripper slides (193). The two gripper slides (193) are coupled to a control element (195) by means of a wedge-hook mechanism (not shown). In this embodiment, the control element (195) is designed as a plunger (195). If the plunger (195) is shown in the illustration of the Fig. When the plunger (195) is moved upwards, the gripper slides (193) are displaced outwards along the guide groove (194). When the plunger (195) is lowered, the gripper slides (193) are pulled towards the center.

[0011] The tool module (190) can also be configured as a centric gripping unit. In a centric gripping unit, for example, three gripper slides (193) that can be moved radially are actuated by means of a common control element (195).

[0012] It is also conceivable to actuate the tool module (190) by means of a rotary control element (195). To transmit the movement from the rotary control element (195) to, for example, the linearly moving gripper slides (193), rack and pinion drives can be used. For example, the gripper slides (193) then carry rack segments that mesh with a control element designed as a gear.

[0013] Other embodiments of the tool module (190) are also conceivable.

[0014] The modules (20, 190, 200) are interchangeable. For example, a group consisting of a drive module (20) and an electronics module (200) can be combined with a different tool module (190). Replacing, for example, the drive module (20) is also possible if a more powerful drive module (20) is required for a specific application.

[0015] The drive unit (22) of the drive module (20) has a drive motor (23), a switchable freewheel (41), and an output assembly (80). In this embodiment, the drive motor (23) is an electric motor in the form of a brushed DC motor. However, it can also be a brushless DC motor, an external rotor motor, a stepper motor, etc. The drive motor (23) has two drive directions (24, 25) that are opposite to each other. These drive directions (24, 25) are referred to below as the first drive direction (24) and the second drive direction (25). The drive motor (23) is, for example, designed without a brake.

[0016] The rotatable motor shaft (26) of the drive motor (23) carries a drive pinion (27). This pinion is part of a drive transmission (28), which is designed as a pre-drive. The drive pinion (27) meshes with an intermediate gear (29), which in turn engages with an output gear (31). In this embodiment, all gears (27, 29, 31) are spur gears with straight teeth. The reduction ratio in this embodiment is 1:4. The pre-drive can also be designed with helical gears, as a transmission with intersecting or overlapping axes, as a traction drive, e.g., in the form of a toothed belt drive, etc. Optionally, the drive unit (22) can also be designed without a pre-drive.

[0017] The switchable freewheel (41) is a self-engaging, direction-switching clutch. It has a locked state and a freewheel state in each direction of rotation. In the exemplary embodiment, the switchable freewheel (41) is a sprag clutch. The locking elements (42) are designed as cylindrical rollers. The use of a sprag clutch, a toothed pulley freewheel, a slip clutch, etc., is also conceivable.

[0018] The one in the Fig. The freewheel (41) shown in Figures 6-11 has an outer ring (43), a drive ring (51), an inner star (61), for example six locking elements (42), compression springs (71), a support washer (72), and spring washers (73). The maximum pivot angle of the freewheel between the freewheel position (57) and the locked position (58) is, for example, less than 20 degrees. In the exemplary embodiment, it is 16 degrees.

[0019] The outer ring (43) is fastened to the drive housing (21) by means of fastening screws. These are arranged, for example, at a 45-degree angle to the plane of the cut. The outer ring (43) has a largely cylindrical outer ring (44) in which head bearings (45) for the fastening screws are formed. The inner surface (46) of the outer ring (44) is designed as a cylindrical running surface (46). A base plate (47) is integrally formed on the outer ring (44). This base plate (47) is oriented perpendicular to a longitudinal direction (35) of the drive module (20). It has a central opening (48) whose diameter is 65% of the diameter of the running surface (46) of the outer ring (44).

[0020] The Fig. Figure 8 shows an isometric view of a drive ring (51). The drive ring (51) has a drive pin (52). When the freewheel (41) is installed, the driven gear (31) is positively engaged with this drive pin (52). For example, the torque transmission from the driven gear (31) to the drive ring (51) is ensured by means of three dowel pins (33). These dowel pins (33) are located in dowel pin recesses (32) of the driven gear (31) and the drive ring (51). The drive ring (51) has a through bore (53) oriented in the longitudinal direction (35). Its diameter is, for example, 60% of the diameter of the drive ring (51).

[0021] On the side facing away from the output shaft (52), the drive ring (51) has three drive pins (54) oriented in the longitudinal direction (35). These are identical in construction and arranged on a common pitch circle. Each drive pin (54) covers a 45-degree segment. In the exemplary embodiment, its flanks (55) enclose an angle of 60 degrees. The thickness of each drive pin (54) is, in the exemplary embodiment, one-ninth of the diameter of the drive ring (51). The length of each drive pin (54) oriented in the longitudinal direction (35) is, for example, twice this thickness.

[0022] Between each pair of drive pins (54) a sliding pin (56) is arranged. Its length is, for example, one-ninth the length of the individual drive pin (54). In a projection normal to the longitudinal direction (35), it has a rectangular cross-sectional area. The radially oriented side length is one and a half times the circumferentially oriented side length.

[0023] In the Fig. Figure 9 shows an inner star (61). The inner star (61) has a circumcircle whose diameter is, for example, one-tenth of a millimeter smaller than the diameter of the drive ring (51). This circumcircle defines three radially oriented stop pins (62). The stop pins (62) are identical in construction and arranged on a common pitch circle. Each stop pin (62) projects from a central disk (63). Each stop pin (62) covers, for example, a segment of 22 degrees outside the central disk (63). Tangential to a circle coaxial with the circumcircle, each stop pin (62) has a receiving bore (64) designed as a through-hole. A compression spring (71) is located in each of these receiving bores (64) when the freewheel is installed. The longitudinal length (35) of each stop pin (62) is, for example, one-fifth of the diameter of the inner star (61).Each of the stop pins (62) is symmetrical to a radial plane of the inner star (61).

[0024] In the exemplary embodiment, the central disk (63) has a diameter of 76% of the circumference of the inner star (61). The length of the inner star (61) oriented in the longitudinal direction (35) corresponds to the length of the individual stop pin (62). The central disk (63) has a central opening (65) whose diameter is, for example, 40% of the diameter of the circumference of the inner star (61).

[0025] The lateral surface (66) of the central disk (63) is designed as a guide surface (66). The stop pins (62) project from this guide surface (66). Between the stop pins (62), the guide surface (66) is symmetrical about a radial plane of the inner star (61). The guide surface (66) has a circular segment (67) to which ramp segments (68) and transition segments (69) connect towards the stop pins (62).

[0026] The circular segment (67) has the diameter of the central disk (63) mentioned above. It covers, for example, a sector angle of 42 degrees. The ramp segments (68) enclose an angle of, for example, 23 degrees with a tangent to the circular segment (67). The maximum depth of each ramp segment (68) is, for example, 0.6 millimeters. In the exemplary embodiment, the transition segment (69) has a radius of 1.4 millimeters. This radius is, for example, 93% of the radius of the locking element (42) used in the exemplary embodiment. Areas of the receiving bores (64) are formed in the transition segments (69).

[0027] On the side of the inner star (61) facing away from the stop pin (62), a stop surface (75) is formed. This surface is oriented perpendicular to the longitudinal direction (35). Next to the stop surface (35), two drive blocks (76) project from the inner star (61) and are oriented perpendicular to the stop surface (35). The drive blocks (76) have drive surfaces (77) oriented parallel to each other.

[0028] The locking elements (42), designed as clamping elements (42), are six cylindrical rollers in the exemplary embodiment. All clamping elements (42) have identical dimensions. The length of each individual clamping element (42) is, for example, 5 millimeters. In the illustration of the Fig. In section 7, a clamping element (42) rests against a ramp section (68) of the inner star (61). In this illustration, the clamping elements (42) are, for example, slightly spaced apart from the running surface (46). Each compression spring (71) loads two clamping elements (42). These clamping elements (42) are arranged on both sides of a stop pin (62).

[0029] A spring washer (73) rests on the base disk (47) of the outer ring (43), and this spring washer supports a support disk (72). The inner star (61) with the clamping elements (42) rests on the support disk (72). The inner star (61) and the locking elements (42) are biased towards the drive ring (51) by means of the spring washer (73).

[0030] The freewheel (41) is attached to the output assembly (80). A support ring (34) serves this purpose, which extends through the drive ring (51). For example, the drive ring (51) is mounted on the support ring (34) in a sliding manner. The support ring (34) has a retaining collar (36) perpendicular to the longitudinal direction (35). This retaining collar (36) engages the drive ring (51) with clearance.

[0031] The output assembly (80) has an input shaft (81), an output body (151), and at least one potential energy storage device (141; 145). The potential energy storage device (141; 145) is located in the force flow between the input shaft (81) and the output body (151). The force driving the output body (151) is transmitted from the input shaft (81) via the potential energy storage device (141; 145) to the output body (151). The input shaft (81) is rotatably mounted in the drive housing (21) about its longitudinal axis, which is oriented in the longitudinal direction (35). The output body (151) has either one translational or one rotational degree of freedom.

[0032] With one translational degree of freedom of the output body (151), a bearing (181) arranged in the drive housing (21) limits the movement of the output body (151) to two oppositely oriented translational directions (182, 183). This bearing (181) is, for example, a translational bearing in the form of a sliding bearing, linear rolling bearing units such as recirculating ball shoes, etc. Rotation of the output body (151) is blocked by the translational bearing (181). The translational directions of movement (182, 183) are, for example, oriented in the longitudinal direction (35) of the drive module (20). However, the translational directions of movement (182, 183) can also be oriented obliquely or transversely to the longitudinal direction (35). The output group (80) can include a gear unit (83) that converts a rotary motion of the input shaft (81) into a translational motion of another gear unit.This transmission (83) can be a rack and pinion transmission, a screw transmission, a worm gear, a crankshaft transmission, etc. From this further transmission element, e.g., the transmission output, the kinetic energy is transferred to the output body (151) under load of the storage (141; 145) of potential energy.

[0033] With one rotational degree of freedom (184) of the output body (151), the output body (151) is rotatably mounted in the drive housing (21) in two opposite directions of rotation (184, 185), cf. Fig. 19. For this purpose, a bearing (153) in the form of a radial or axial bearing is used, for example. These directions of rotation (184, 185), the rotational degrees of freedom (184, 185), are oriented, for example, in a plane normal to the longitudinal direction (35). However, the output body (151) can also be rotatable about an axis of rotation that is not oriented in the direction of the longitudinal axis (35). The output assembly (80) used for this purpose can have a gear unit that converts a rotary motion into a rotary motion. This can be, for example, a rolling gear unit in the form of a spur gear unit, a bevel gear unit, a helical gear unit, etc.

[0034] The support ring (34) is attached to the end face of the input shaft (81) by means of a release screw (37). In the exemplary embodiment, this release screw (37) has an internal hexagon socket (38). A blocked input shaft (81) can be released by means of a tool engaging in the internal hexagon socket (38). The drive housing (21) has, for example, a mounting cover (39) for this purpose. Other designs of the freewheel emergency release device (37, 38) are also conceivable. For example, the input shaft (81) can have a hexagon that can be gripped with a tool. The design of a lever or handle for emergency release is also conceivable. It is also conceivable to design the freewheel emergency release device on one of the gears of the drive transmission (28). For example, a tool engagement for emergency release can be provided on the drive pinion (27).

[0035] The freewheel (41) is in contact with the drive blocks (76) of the inner star (61) on complementary drive surfaces (82) of the input shaft (81) for the transmission of the drive torques.

[0036] In the exemplary embodiment, the output assembly (80) has a transmission (83) that transmits a rotary motion of the input shaft (81) into a translational motion of a further transmission element. This transmission (83) is shown in the illustrations of the Fig. 2, 3 and 12-17 a planetary roller gear (90). The planetary roller gear (90) has a gear spindle (91), several planetary rollers (101) and two gear nuts (111, 131). In this embodiment, the gear nuts (111, 131) form the aforementioned additional gear element.

[0037] In this embodiment, the input shaft (81) is formed by the gear spindle (91), see the Fig. 12 and Fig. 14. The gear spindle (91) has, for example, a length of 53 millimeters and a maximum diameter of 25 millimeters. It is manufactured as a turned part. The threaded spindle (91) has a guide pin (92) on which the inner star (61) sits. A bearing flange (93) is attached to this. This bearing flange (93) is disk-shaped. It lies in a plane perpendicular to the longitudinal direction of the gear spindle (91). In the assembled state, a rolling bearing (94, 95) in the form of an axial bearing (94, 95) is arranged on each side of the bearing flange (93). The bearing in the Fig. The two upper rolling bearings (94) are supported in the drive housing (21). The lower rolling bearing (95) runs on a compensating washer (96), which is supported in the drive housing (21) by means of a spring washer (97).

[0038] At the end opposite the bearing flange (93), the gear spindle (91) has a threaded section (98). The length of the threaded section (98) is, for example, 40% of the total length of the gear spindle (91). The outer diameter of the threaded section (98) is, for example, 40% of the diameter of the bearing flange (93). The core diameter of the gear spindle (91) in the threaded section (98) is 90% of the outer diameter of the threaded section (98). The threaded section (98) has a pitch of, for example, one millimeter. The profile of the thread (99) of the threaded section (98) is, for example, trapezoidal.

[0039] The Fig. Figure 15 shows a planetary roller (101). The planetary roller gear (90), for example, has four planetary rollers (101) surrounding the gear spindle. The planetary rollers (101) are arranged on a common pitch circle. Their ends are held there in ring carrier disks (102).

[0040] The individual planetary roller (101), for example, has a length of 24.6 millimeters and a maximum diameter of 4.7 millimeters. It is manufactured, for example, on a lathe. The average surface roughness R z According to DIN 4768 Part 1, for example, it is greater than 4 micrometers. In its longitudinal direction, the individual planetary roller (101) has three profile sections (103 - 105). These are two outer profile sections (103, 104) and a middle profile section (105). The middle profile section (105) meshes with the gear spindle (91).

[0041] The two outer profile sections (103, 104) are identical in design. Their length is, for example, 21% of the total length of the planetary roller (101). The diameter of the outer profile sections (103, 104) is, for example, 72% of the maximum diameter of the planetary roller (101). The core diameter of the outer profile sections (103, 104) is, for example, 67% of the diameter of this area. The profiling of the outer profile sections (103, 104) consists of circumferential grooves (106). These have a V-shaped cross-section and a rounded groove base. The pitch of the profiling is, for example, one millimeter.

[0042] The central profile section (105) has a length of, for example, 29% of the length of the planetary roller (101). In this central profile section (105), the core diameter is 80% of the maximum diameter of the planetary roller (101). The profile of the central section (105) has circumferential grooves (107). The pitch of this profile corresponds to the pitch of the profile of the outer profile sections (103, 104).

[0043] The Fig. Figure 16 shows a gear nut (111; 131). The planetary roller gear (90) has two gear nuts (111, 131) that engage the gear spindle (91) and the planetary rollers (101). The gear nuts (111, 131) are identical in design.

[0044] The individual gear nut (111; 131) has a guide flange (112; 132), a transition section (113), and a tube section (114) integrally formed with these. The guide flange (112; 132) is disc-shaped. In the exemplary embodiment, it is oriented perpendicular to the longitudinal direction (35). On its circumferential surface (115), the guide flange (112; 132) has a guide recess (116). This continuous guide recess (116) has, for example, a rectangular cross-section. The end face (117) of the guide flange (112) has, for example, six spring receptacles (118) arranged on a common pitch circle. When the planetary gear set (90) is mounted, the guide flanges (112, 132) of the two gear nuts (111, 131) face each other. Compression springs (126) are located in the spring receptacles (118) of both gear nuts (111, 131), so that the gear nuts (111, 131) support each other in the longitudinal direction (35) and push apart.

[0045] The pipe section (114) has a cylindrical outer surface (119). Its length is, for example, half the length of the gear nut (111; 131). On its inner wall (121), the pipe section (114) has a profiled area (122). This area has a plurality of circumferential inner grooves (123) arranged side by side in the longitudinal direction (35). The spacing of these inner grooves (123) corresponds to the spacing of the outer profiled sections (103, 104) of the profile rollers (101). The length of the profiled area (122) corresponds, for example, to the length of one outer profiled section (103, 104) of a planetary roller (101). This profiled area (122) meshes with one outer profiled section (103; 104) of each planetary roller (101) for each gear nut (111; 131). The individual gear nut (111; 131) surrounds one of the ring carrier discs (102). This is secured in the gear nut (111; 131) by means of a retaining ring (125).

[0046] With the output assembly (80) mounted, a guide block (133) engages in the guide recesses (116) of both gear nuts (111, 131). The guide block (133) has, for example, the shape of a round-faced key according to DIN 6885 T2 Form A. In the exemplary embodiment, it has a length of 12 millimeters, a width of 4 millimeters, and a height of 4 millimeters. Both gear nuts (111, 121) are individually displaceable relative to the guide block (133) in the longitudinal direction (35).

[0047] The guide block (133) is positively fitted into a gearbox housing (161). The gearbox housing (161) has a guide block receptacle (166) for this purpose. In this embodiment, the gearbox housing (161) forms the output body (151) of the output assembly (80). The gearbox housing (161) is cup-shaped. It has an end wall (162) and a shell (163). The gearbox housing (161) has, for example, a length of 42 millimeters and a diameter of 37 millimeters. The gearbox housing (161) carries two sliding rings (164) on its shell surface. By means of these sliding rings (164), the gearbox housing (161) is slidably mounted in the drive housing (21) in the longitudinal direction (35). The maximum axial stroke of the gearbox housing (161) in the drive housing (21) is, for example, 12 millimeters. Two guide pins screwed into the end face of the gearbox housing (161), e.g. in guide pin threads (165), slide along guide pin grooves (171) of the gripper housing (11).This anti-rotation device (172) prevents the output body (151) from rotating relative to the drive housing (21). A connecting screw (173) is used to connect, for example, a tool module (190). A locking pin (174) inserted in a transverse bore prevents the connecting screw (173) from rotating relative to the gearbox housing (161).

[0048] On its inner wall (167), the gearbox housing (161) has three annular grooves (168, 169) for receiving retaining rings for bores. The distance between the two outermost annular grooves (168) is equal to the distance of the third annular groove (169) to the end wall (162).

[0049] Between the end wall (162) and the second gear nut (131) and between the outer retaining ring (175) and the first gear nut (111), a potential energy storage element (141; 145) is arranged. Each potential energy storage element (141; 145) is elastically deformable and self-recovering. The potential energy storage element (141; 145) is hereinafter also referred to as a compensating element (141; 145). In the exemplary embodiment, the individual compensating element (141; 145) is formed by a disc spring assembly (142). This disc spring assembly (142) is, for example, preloaded. The preload in the exemplary embodiment is between 250 and 600 Newtons. It is also conceivable to design the compensating element (141) as a helical compression spring, ring spring, leaf spring, etc. The residual deformation stroke of the individual disc spring assembly (142) during compression is, for example, 2.8 millimeters.

[0050] The illustrated disc spring assembly (142) has four disc springs (143). These are, for example, connected in series. In the exemplary embodiment, each individual disc spring (143) has an outer diameter of 31.75 millimeters, an inner diameter of 21.75 millimeters, and a height of 1.75 millimeters in its undeformed state. The individual disc spring assembly (142) sits on the tube section (114) of a gear nut (111; 131). A stepped washer (144) supports the disc spring assembly (142) against the gear nut (111; 131).

[0051] A measuring device (211) is arranged on the outside of the gripper housing (11). This device includes, for example, two magnetic field sensors (212). These magnetic field sensors (212) are adjustable along two parallel adjustment rails (213). In the illustration of the Fig. 1 The two magnetic field sensors (212) are arranged offset from each other in the longitudinal direction (35). The two magnetic field sensors (212) determine, for example, the position of the metallic plunger (195) of the tool unit (192).

[0052] As an alternative measuring device, the positions of the gripper jaws can be determined using force sensors or a displacement measuring system. Such a measuring device can be used, for example, to determine whether a workpiece has been gripped or not.

[0053] By means of a further alternative or additional measuring device, it can also be monitored whether the actual voltage of the disc spring assembly (142), i.e., the actual charge of the storage device (141; 145) of potential energy, is greater than the preload applied during assembly. For this purpose, for example, a displacement measuring system can be used in the gearbox housing (161) to determine the position of the gearbox nuts (111, 131). Two limit switches in the gearbox housing (161) are also conceivable.

[0054] The number of revolutions of the motor shaft (26) or the gear spindle (91) after reaching a gripper slide target position specific to the material being gripped can also be determined as a measure of the gripping force achieved. This is done, for example, using a rotary encoder. Instead of the gripper slide target position specific to the material being gripped, the gripper (10) can also be used as the starting point for such a determination. In this case, a stored tolerance can be taken into account.

[0055] Another alternative method for determining the actual charge of the storage (141; 145) of potential energy can be carried out using the time interval in which the motor current continues to increase after gripping a gripping object.

[0056] To move, for example, the gripper slides (193) of the tool module (190), the drive motor (23) is switched on. The drive motor (23) rotates the drive pinion (27), for example, in a first drive direction (24). The output gear (31), which is attached to the drive ring (51), is driven via the intermediate gear (29). In this embodiment, the direction of rotation of the drive ring (51) coincides with the drive direction (24) of the motor shaft (26).

[0057] The drive ring (51) moves the clamping elements (42) towards the stop pins (62). The inner star (61) is rotated around the central axis (49) of the freewheel (41) in the direction of rotation of the drive ring (51). This central axis (49) is oriented, for example, in the longitudinal direction (35). In doing so, the inner star (61) engages the positively coupled input shaft (81), for example, the gear spindle (91).

[0058] The planetary rollers (101) roll on the rotating threaded spindle (91), being displaced in the longitudinal direction (35). For example, the rotating planetary rollers (101) are displaced linearly opposite to the direction of the tool module (190). The planetary rollers (101) engage the gear nuts (111, 131) via the engagement of the circumferential grooves (106). The guide block (133) prevents the gear nuts from rotating relative to the output body (151). The two threaded nuts (111, 131) are forced apart by the compression springs (126) so that the outer flanks of the inner grooves (123) bear against the inner flanks of the circumferential grooves (106).

[0059] In this example, the translational movement of the threaded nuts (111; 131) is transferred to the output body (151) by means of the first compensating element (141; 145). The compensating element (141; 145) lies in the force path between the input shaft (81) and the output body (151). With low resistance and / or moment of inertia of the output body (151) and the tool module (190), the compensating element (141; 145) is only slightly deformed in addition to the preload. The exact position of the tool unit (192) of the tool module (190) can be determined using the measuring device (211).

[0060] In the described example, the tool module (190) is designed as an external gripping module whose gripping elements engage with the workpiece from the outside. When the gripping elements engage with the workpiece, the load-side resistance on the output body (151) increases, preventing further movement of the output body (151) in the translational direction (182; 183). During continued operation of the drive motor (23), the compensating element (141; 145) is compressed. The gripping force is maintained. The kinetic energy output by the drive motor (23) is converted into potential energy stored in the potential energy storage element (141; 145). The output body (151) is thus inhibited from further movement, for example, by the load on the workpiece side. Inhibition of the output body (151) is also conceivable by means of a brake or clamping device that restricts the movement of the output body (151). Such a brake or clamp can be operated manually or automatically.For example, it surrounds the gearbox housing (161) and, in the closed operating state, blocks the translational or rotational degree of freedom of the output body (151).

[0061] The drive motor (23) can now be switched off. The compensating element (141; 145) relaxes slightly. This causes the input shaft (81) to rotate in the opposite direction to the direction of rotation of the input shaft (81) caused by the aforementioned drive rotation (24; 25). In the exemplary embodiment, this movement is transmitted via the non-self-locking planetary gear (90). Even with a design using, for example, a differently configured non-self-locking gear (83), the input shaft (81) rotates in the opposite direction.

[0062] The input shaft (81) of the output assembly (80) engages the inner star (61) of the switchable freewheel (41). The inner star (61) moves the clamping elements (42) into the locking position (58) of the counter-rotation direction, which is opposite to the original rotation direction of the drive ring (51). The freewheel (41) thus forms an energy sink for the drive unit (22). The drive train of the output assembly (80) is blocked by the load acting on the output body (151) and the freewheel (41). The potential energy storage device (141; 145) is at least partially charged, with the charge level being higher than the preload applied during assembly. The input shaft (81) and the output body (151) can no longer move relative to each other or relative to the drive housing (21). An additional locking brake is not required for the output assembly (80).

[0063] For example, after the gripped item has been placed down, the gripper (10) should be opened again. For this purpose, the drive motor (23) is rotated in the second drive direction (25; 24). In the exemplary embodiment, the drive motor (23) drives the drive ring (51) in the aforementioned drive direction (25; 24) by means of the drive gearbox (28). The locked clamping elements (42) are released from the locked position (58) by means of the drive ring (51) and moved into the free-running position (57).

[0064] The input shaft (81) follows the inner star (61) of the freewheel (41). In this example, the planetary rollers (101) are displaced in the direction of the tool module (190) and also displace the gear nuts (111; 131) in this direction. The compensating elements (141; 145) deform themselves back to their original shape.

[0065] In this direction of movement, the gear nuts (111; 131) transmit their translational motion via the second compensating element (145; 141) to the output body (151). The high gear ratio of the drive gear (28) and the planetary roller gear (90) enables a high output torque. If necessary, the compensating element (145; 141) can be compressed to generate a breakaway torque. In the exemplary embodiment, the gripper slides (193) in the tool module (190) are moved outwards. The workpiece is released.

[0066] When the tool module (190) is used as an internal gripper, the compensating element (145; 141), referred to here as the second compensating element (145; 141), is compressed when the workpiece is gripped. The freewheel (41) is correspondingly blocked in the opposite direction. To release the internal gripper, the motor shaft (26) of the drive motor (23) is rotated in the first drive direction (24; 25).

[0067] The Fig. Figure 18 shows a drive unit with a differently constructed output assembly (80). The drive motor (23), the drive gearbox (28), and the freewheel (41) are designed, for example, as described in connection with the first embodiment. The drive motor (23) is, for example, attached to the drive housing (21). The inner star (61) of the freewheel (41) is positively connected to the input shaft (81) of the output assembly (80).

[0068] In the output assembly (80), the gearbox housing (161) forms the input shaft (81) and the gearbox spindle (91) forms the output body (151). The gearbox housing (161) is mounted on roller bearings in the drive housing (21). Fig. Figure 18 shows two rolling bearings (176) in the simplified form of deep groove ball bearings.

[0069] In this embodiment, the power flow from the input shaft (81) is direction-dependent and runs via one of the compensating elements (141; 145) to one of the gear nuts (111; 131). Both gear nuts (111; 131) are secured against rotation relative to the gearbox housing (161). Thus, the speed and direction of rotation of the gear nuts (111; 131) relative to the drive housing (21) correspond to the speed and direction of rotation of the gearbox housing (161) relative to the drive housing (21). In this embodiment, end pins (not shown) serve as the anti-rotation device for the gear nuts (111; 131) relative to the gearbox housing (161). However, the anti-rotation device can also be designed as described in connection with the first embodiment. In all cases, the anti-rotation device allows translational movement of the gear nuts (111; 131) relative to the gearbox housing (161).In this embodiment, the two gear nuts (111; 131) do not have compression springs (126) arranged between them.

[0070] In this embodiment, the compensating elements (141, 145) are constructed as described in connection with the first embodiment. They are each preloaded in the longitudinal direction (35) between the gearbox housing (161) and a gearbox nut (111; 131). Support or compensating washers can also be used here. The disc springs (143) surround the gearbox spindle (91), the planetary rollers (101), and the tube sections (114) of the gearbox nuts (111, 131).

[0071] The planetary rollers (101) roll on the gear nuts (111, 131). The planetary rollers (101) are mounted at their ends in ring carrier discs (102). The ring carrier discs (102) are held in the gear nuts (111, 131) to prevent rotation. In this embodiment, a retaining ring (175) limits the translational movement of the planetary rollers (101) and the ring carrier discs (102) relative to the respective gear nut (111; 131).

[0072] In this embodiment, the planetary rollers (101) are designed as described in connection with the first embodiment. They each have two outer profile sections (103, 104) with circumferential grooves (106) that engage in corresponding inner grooves (123) of the threaded nuts (111, 131). Between these outer profile sections (103, 104), each planetary roller (101) has a central profile section (105). This section meshes with the gear spindle (91).

[0073] The gear spindle (91) is mounted axially displaceably in the drive housing (21). It has a threaded section (98) with a thread (99). The thread (99) is designed, for example, as described in connection with the first embodiment.

[0074] The torque from the rotating motor shaft (26) of the drive motor (23) is transmitted via the freewheel (41) to the gearbox housing (161). The gearbox housing (161) transmits the rotational motion to the gear nuts (111, 131) and the planetary rollers (101) by means of the anti-rotation device. The rotating planetary rollers (101) roll against the gearbox spindle (91). In doing so, the planetary rollers (101) are supported longitudinally (35) by the gear nuts (111, 131) and the compensating elements (141, 145) on the gearbox housing (161). The rotating planetary rollers (101) move the gearbox spindle (91) in the translational direction of motion (182; 183). The feed of the gear spindle (91) is thus supported via the compensating elements (141, 145) on the gear housing (161).

[0075] For example, when gripping a workpiece by contact, the translational movement of the output element (151) is inhibited. The drive motor (23), which continues to be energized, increases the gripping pressure on the workpiece. The compensating element (141; 145) located in the force path is compressed.

[0076] When the drive motor (23) is switched off, the compressed compensating element (141; 145) is slightly relieved of its load. This displaces the associated gear nut (111; 131) relative to the gear housing (161) in a translational direction. In doing so, the planetary rollers (101) are engaged, which roll on the locked gear spindle (91). The planetary rollers (101), rotating around the gear spindle (91), engage the gear nuts (111, 131) and the gear housing (161) via the ring carrier discs (102). The gear housing (161) is rotated in the opposite direction to its original rotation, which is controlled by the drive direction (24; 25) of the drive motor (23). The inner star (61) of the freewheel (41) is rotated relative to the drive ring (51) such that the freewheel (41) locks.

[0077] The opening of the gripper, e.g. when placing the gripped item, takes place in the opposite direction.

[0078] In the Fig. Figure 19 schematically illustrates another embodiment. The drive motor (23) and the freewheel (41) are designed as described in connection with the previous embodiments. The output assembly (80) has an input shaft (81) which is supported in the drive housing (21) by means of rolling bearings (84). The input shaft (81) has only rotational degrees of freedom.

[0079] In this embodiment, the output body (151) is a rotatably mounted output shaft (152). The tool module (190) that can be connected to it can, for example, have a worm gear that drives two translationally movable gripper slides (193) in opposite directions. An axial displacement of the output shaft (152) is blocked by means of the output shaft bearing (153).

[0080] In this embodiment, a storage device (141; 145) of potential energy in the form of a torsion element (146) is arranged between the input shaft (81) and the output body (151). Instead of the one in the Fig. The torsion spring shown in Figure 19 (147) could be, for example, a torsion bar, a torsion disc, etc.

[0081] For example, when gripping a workpiece, the drive motor (23) rotates the input shaft (81) via the freewheel (41). This shaft, via the compensating element (141) located in the power transmission path, drives the output body (151). The output body (151) actuates the tool unit (192) of the tool module (190). Optionally, a measuring sensor can detect the angular position of the output body (151) relative to the input shaft (81). After the gripping elements are applied to the workpiece, the gripping force depends on the rotation angle of the output body (151) from that point onward. During this process, the compensating element (141) is elastically deformed. In this embodiment, it is twisted. The force applied to the workpiece by the gripping elements acts as an external load on the output body (151). This load is oriented opposite to the movement of the output body (151) generated by the drive motor (23).As soon as the drive motor (23) is switched off, the self-deforming compensating element (141) loads the input shaft (81). The freewheel (41) is switched into the locked position.

[0082] When the gripped item is placed down, the gripping elements are opened. For this purpose, the drive motor (23) is rotated in the opposite direction. The freewheel (41) is released and the compensating element (141) deforms back into its initial position.

[0083] When the drive module (20) is used with a tool module (190) designed as an external gripper, the compensating element (141) is twisted in the opposite direction when it is brought into contact with the workpiece. The freewheel (41) locks accordingly in the opposite direction. When the workpiece is released, the compensating element (141) deforms back to its original shape in this case as well.

[0084] It is conceivable to combine the individual implementation examples with each other. Reference symbol list: 10 grippers, electric grippers 11 Gripper housings 20 Drive module 21 Drive housings 22 Drive unit 23 Drive motor 24 Drive direction of rotation, first drive direction of rotation 25 Drive direction of rotation, second drive direction of rotation 26 Motor shaft 27 drive pinions 28 Drive gearboxes 29 Intermediate wheel 31 Output gear 32 dowel pin recesses 33 dowel pins 34 Support ring 35 Longitudinal direction 36 Security Alliance 37 Release screw, part of the freewheel emergency release device 38 Hex socket, part of the freewheel emergency release device 39 Mounting covers 41 Freewheel, switchable 42 Locking elements, clamping elements 43 Outer ring 44 mantle ring 45 headrests 46 Inside of (44), tread surface 47 Base plate 48 Breakthrough of (47) 49 Central axis of (41) 51 Carpool ring 52 Drive pins of (51) 53 Through hole 54 take-away cones 55 flanks of (54) 56 sliding pins 57 Freewheel position 58 Blocking position 61 Inner star 62 stop pins 63 Central disc 64 Mounting hole 65 Breakthrough of (63) 66 Surface area of ​​(63), guide surface 67th section of the circle 68 ramp sections 69 transition sections 71 compression springs 72 Support disc 73 spring washers 75 Stop surface 76 transport blocks 77 carry-on areas 80 Drive group 81 Input shaft 82 carry-on areas 83 gearboxes 84 rolling bearings 90 planetary roller gears 91 Gear spindle 92 guide pins 93 Bearing flange 94 rolling bearings, axial bearings 95 rolling bearings, axial bearings 96 shim 97 Spring washer 98 thread section 99 threads 101 Planetary Role 102 ring carrier discs 103 outer profile section 104 outer profile section 105 middle profile section 106 circumferential grooves of (103, 104) 107 circumferential grooves of (105) 111 Gear nut, gear part 112 Guide flange 113 Transition section 114 Pipe section 115 Circumferential area 116 Lead reduction 117 Front 118 spring mounts 119 Surface area of ​​(114) 121 Inner wall of (114) 122 Profile area 123 circumferential grooves, inner grooves 125 retaining ring 126 compression springs 131 Gear nut, gear part 132 Guide flange 133 Guide block 141 Storage of potential energy, balancing element 142 Disc spring assembly 143 Belleville washers 144 stepped disc 145 Storage of potential energy, balancing element 146 Torsion element 147 Torsion spring 151 Drive bodies 152 Output shaft 153 Output shaft bearing 161 Gearbox housing 162 Front wall 163 Coat 164 sliding rings 165 guide bolt threads 166 Guide block recording 167 Inner wall 168 ring grooves 169 Ring groove, middle ring groove 171 guide pin grooves in (11) 172 Anti-rotation device 173 Connecting screw 174 Safety pin 175 Retaining ring, outer retaining ring 176 rolling bearings 181 translational storage of (151) in (21) 182 translational direction of movement of (151) 183 translational direction of movement of (151) 184 rotational degrees of freedom, direction of rotation of (151) 185 rotational degrees of freedom, direction of rotation of (151) 190 tool module 191 Tool housings 192 tool unit 193 gripper slides 194 guide groove 195 Control element, plunger 200 electronic module 201 Electronic enclosures 202 Electronic unit 211 Measuring device 212 magnetic field sensors 213 adjustment rails QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2017 124 386 A1

[0002]

Claims

[1] Output group (80) with a planetary roller gear (90) comprising an input shaft (81) rotatably mounted in a drive housing (21) and two gear nuts (111; 131), characterized by , - that the gear nuts (111; 131) are mounted in a rotationally fixed manner relative to a gear housing (161) and are displaceable in the translational direction, - that the gearbox housing (161) or a gearbox spindle (91) forms an output body (151) of the output group (80), - that the output body (151) is mounted in the drive housing (21) in a rotationally secure manner and is guided in translational directions of movement (182, 183) in the drive housing (21), - that a repeatedly chargeable and dischargeable storage device (141; 145) of potential energy is arranged in the power flow between each gear nut (111; 131) and the gear housing (161), - that, in the case of a locked output body (151), an approximation of the gear nut (111; 131) and the gear housing (161) relative to each other, effected by a rotation of the input shaft (81), charges the storage device (141; 145) of potential energy associated with one of these gear nuts (111; 131) and located in the power flow and - that this storage (141; 145) of potential energy supplies kinetic energy to an at least temporary energy sink. [2] Drive group (80) according to claim 1, characterized by , that the input shaft (81) is a gear spindle (91) with a bearing flange (93) which is mounted in the drive housing (21) by means of two axial bearings (94, 95). [3] Drive group (80) according to claim 1, characterized by , that the gear spindle (91) penetrates two ring carrier disks (102) in which planetary rollers (101) of the planetary roller gear (90) are rotatably mounted. [4] Drive group (80) according to claim 3, characterized by, that the planetary rollers (101) are manufactured by means of a turning operation on a lathe, wherein the average roughness depth R z according to DIN 4768 Part 1 is larger than 4 micrometers. [5] Drive group (80) according to claim 1, characterized by , that the individual storage device (141; 145) of potential energy is a balancing element in the form of a disc spring pack (142). [6] Drive group (80) according to claim 5, characterized by , that both disc spring assemblies (142) are oriented in the longitudinal direction (35) of the output group (80). [7] Drive group (80) according to claim 1, characterized by , that the driven body (151) can be inhibited either by external forces or by internal forces. [8] Drive group (80) according to claim 1, characterized by , that a switchable freewheel (41) is connected upstream of the input shaft (81). [9] Drive group (80) according to claim 8, characterized by, that when the storage (141; 145) of potential energy is fully charged and the driven body (151) is inhibited, the switchable freewheel (41) forms an energy sink. [10] Drive group (80) according to claim 9, characterized by , that the switchable freewheel (41) has a locking position (58) and a freewheel position (57) for each direction of rotation.

Images