Stepping linear motor and bionic dexterous finger

Abstract

The utility model belongs to the technical field of manipulators, and discloses a stepping linear motor and a bionic dexterous finger. The stator is fixed on the inner wall of the outer shell; the driving nut is rotationally arranged in the outer shell, and the driving nut is arranged on the inner ring of the stator in a penetrating manner; the rotor is wound on the periphery of the driving nut; the lead screw is arranged on the outer shell in a sliding mode in the linear direction, one end of the lead screw extends out of the outer shell, the driving nut is in threaded connection with the lead screw, and the stator can drive the rotor and the driving nut to rotate together after being powered on so as to drive the lead screw to stretch out and draw back linearly relative to the outer shell; and the position detection piece is installed on the outer shell or the lead screw, and the position detection piece is used for detecting the rotation angle of the driving nut. The stepping linear motor has the self-locking performance, the transmission efficiency, the positioning precision and the position control precision are higher, the integration degree is high, and miniaturization design is facilitated.

Description

Technical Field

[0001] This utility model relates to the field of robotic arm technology, and in particular to stepper linear motors and bionic dexterous fingers. Background Technology

[0002] A bionic dexterous hand is a complex device that integrates multiple bionic dexterous fingers, designed to mimic the overall function and dexterity of the human hand. Through advanced control algorithms and sensing technology, the bionic dexterous hand can perform precise object manipulation and grasping in complex operating environments.

[0003] Currently, most bionic dexterous fingers achieve their grasping action by having motors drive the rotation of each finger joint via tendons. This driving method requires continuous power input to the motor to maintain the grasping posture, and it has low integration and insufficient position control precision.

[0004] Therefore, there is an urgent need for a stepper linear motor and a bionic dexterous finger to solve the above-mentioned technical problems. Utility Model Content

[0005] The purpose of this utility model is:

[0006] 1. A stepper linear motor is provided, which has self-locking performance, higher transmission efficiency, positioning accuracy and position control accuracy, and high integration, which is conducive to miniaturization design;

[0007] 2. A bionic dexterous finger is provided, which realizes the grasping action of the bionic dexterous finger through a stepper linear motor. The bending angle of the finger can be precisely adjusted and the bending position of the finger can be controlled. The outer shell of the stepper linear motor and the outer shell of the driving finger joint are integrated to improve space utilization and increase motor power.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, a stepper linear motor is provided, comprising:

[0010] outer shell;

[0011] The stator is fixed to the inner wall of the outer casing;

[0012] A drive nut is rotatably disposed within the housing, and the drive nut passes through the inner ring of the stator;

[0013] The rotor is wound around the outer periphery of the drive nut;

[0014] A lead screw is slidably disposed in the outer casing along a straight line, with one end of the lead screw extending out of the outer casing. A drive nut is threadedly connected to the lead screw. When the stator is energized, it can drive the rotor and the drive nut to rotate together, thereby causing the lead screw to extend and retract linearly relative to the outer casing.

[0015] A position detection component is installed on the housing or the lead screw, and the position detection component is used to detect the rotation angle of the drive nut.

[0016] As a preferred technical solution, the position detection component is embedded in the lead screw at the end opposite to the end extending from the outer casing; or

[0017] The position detection component is fixed to the end of the outer casing away from the end through which the lead screw protrudes.

[0018] As a preferred technical solution, the position detection device is a Hall sensor, a magnetic encoder, or a photoelectric encoder.

[0019] As a preferred technical solution, the stepper linear motor further includes a first bearing and a second bearing, and the drive nut or the rotor is rotatably mounted on the housing via the first bearing and the second bearing.

[0020] As a preferred technical solution, one of the first bearing and the second bearing is a radial bearing, and the other is a thrust bearing; or

[0021] Both the first bearing and the second bearing are angular contact bearings.

[0022] As a preferred technical solution, the first bearing is a radial bearing or an angular contact bearing. The first bearing is located at the end of the drive nut that is away from the lead screw. The first bearing has a first inner ring and a first outer ring. The first inner ring is tightly fitted around the outer periphery of the drive nut, and the first outer ring is fixed to the inner wall of the outer casing.

[0023] As a preferred technical solution, the stepper linear motor further includes a locking block, which is engaged with the outer casing and extends into the inner cavity of the outer casing. A limiting step is provided at the end of the drive nut that extends away from the lead screw. The locking block presses against the side of the first outer ring of the first bearing that extends away from the lead screw, and the side of the first inner ring of the first bearing that extends near the lead screw presses against the limiting step.

[0024] As a preferred technical solution, the second bearing is a thrust bearing, comprising a thrust bearing shaft and a thrust bearing seat spaced apart. A thrust step is provided at the end of the drive nut near the protruding end of the lead screw. An inner flange is provided on the outer casing corresponding to the opening of the protruding lead screw. The thrust bearing shaft abuts against the thrust step, and the thrust bearing seat abuts against the inner flange; or

[0025] The second bearing is an angular contact bearing. The second bearing is located at the end of the drive nut near the protruding end of the lead screw. The second bearing has a second inner ring and a second outer ring. The second inner ring is tightly fitted onto the outer periphery of the drive nut, and the second outer ring is fixed to the inner wall of the outer casing.

[0026] As a preferred technical solution, both the first bearing and the second bearing are angular contact bearings. The stepper linear motor also includes a locking ring. The two ends of the drive nut are respectively fitted with the locking ring. One locking ring presses the first inner ring against the limiting step, and the other locking ring presses the second inner ring against the thrust step.

[0027] Secondly, a bionic dexterous finger is provided, comprising a distal phalanx and a plurality of drive phalanges connected in sequence. The drive phalanges include a stepper linear motor as described above. One end of the lead screw extending out of the housing is connected to the adjacent drive phalange or the distal phalanx to drive the latter to rotate. The housing of the stepper linear motor is integrally formed with the housing of the drive phalanges.

[0028] The beneficial effects of this utility model are:

[0029] The stepper linear motor provided by this utility model converts rotational power into linear power by energizing the stator to drive the rotor and drive nut to rotate together. The drive nut then drives the threaded lead screw to slide relative to the outer casing. Firstly, the self-locking between the drive nut and the lead screw allows for maintaining the telescopic position without continuous power input. Furthermore, the drive nut's action on the lead screw provides higher rigidity, effectively improving transmission efficiency and positioning accuracy. Secondly, the position detection component can detect the rotation angle of the drive nut in real time, thereby detecting the extension length of the lead screw and achieving high-precision position control. Moreover, the drive nut acts as the rotation axis of the stepper linear motor, integrating the position detection component inside the motor, resulting in a highly integrated, compact structure that facilitates miniaturization design.

[0030] The bionic dexterous finger provided by this utility model realizes the grasping action of the bionic dexterous finger through a stepper linear motor. The drive nut and lead screw work together to realize the conversion of rotational power into linear power, and the position detection component detects the rotation angle of the drive nut in real time, which can accurately adjust the bending angle of the finger and control the bending position of the finger. The outer shell of the stepper linear motor is integrated with the outer shell of the drive finger joint, that is, the outer shell of the stepper linear motor serves as the outer shell structure of the bionic dexterous finger. The overall structure is more compact and improves space utilization. A stepper linear motor with greater output power can be set in a limited space, thereby increasing the output power and outputting a larger and more stable gripping force. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the bionic dexterous finger provided in Embodiment 1 of this utility model;

[0032] Figure 2 This is a schematic diagram of the structure of the stepper linear motor provided in Embodiment 1 of this utility model;

[0033] Figure 3 This is a schematic diagram of the structure of the stepper linear motor provided in Embodiment 2 of this utility model.

[0034] In the picture:

[0035] 10. Outer shell; 101. Inner flange;

[0036] 1. Drive nut; 11. Thrust step; 12. Limit step; 2. Lead screw; 3. Stator; 4. Rotor; 5. Position detection component;

[0037] 6. First bearing; 61. First inner ring; 62. First outer ring;

[0038] 7. Second bearing; 71. Thrust bearing plate; 72. Thrust bearing seat plate; 73. Second inner ring; 74. Second outer ring;

[0039] 8. Locking block; 9. Locking ring;

[0040] 100, driving knuckle; 200, distal knuckle. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0042] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0043] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0044] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0045] Example 1:

[0046] like Figure 1 As shown, this embodiment provides a bionic dexterous finger, which includes a distal phalanx 200 and a plurality of drive phalanxes 100 connected in sequence for rotation. Each drive phalanx 100 includes a stepper linear motor, which is connected to an adjacent drive phalanx 100 or distal phalanx 200 for driving the latter to rotate.

[0047] Furthermore, such as Figure 1 and Figure 2 As shown, the stepper linear motor includes a housing 10 and a stator 3, a rotor 4, a drive nut 1, a lead screw 2, and a position detection element 5 disposed within the housing 10. The stator 3 is fixed to the inner wall of the housing 10. The drive nut 1 is rotatably disposed within the housing 10 and passes through the inner ring of the stator 3. The rotor 4 is wound around the outer periphery of the drive nut 1. The lead screw 2 is slidably disposed within the housing 10 along a linear direction. One end of the lead screw 2 (i.e., Figure 2 The upper end of the lead screw 2 extends out of the outer casing 10 and is rotatably connected to the adjacent drive finger 100 or end finger 200 via a rotating shaft; the drive nut 1 is threadedly connected to the lead screw 2. After the stator 3 is energized, it can drive the rotor 4 and the drive nut 1 to rotate together, thereby causing the lead screw 2 to linearly extend and retract relative to the outer casing 10, thereby causing the drive finger 100 or end finger 200 connected to it to rotate. The position detection element 5 is installed on the outer casing 10 or the lead screw 2. The position detection element 5 is used to detect the rotation angle of the drive nut 1.

[0048] Specifically, the bionic dexterous finger provided in this embodiment achieves grasping motion through a stepper linear motor. The stepper linear motor drives the rotor 4 and drive nut 1 to rotate together by energizing the stator 3. The drive nut 1 then drives the threaded lead screw 2 to slide relative to the outer casing 10, thus converting rotational power into linear power. Firstly, the self-locking between the drive nut 1 and the lead screw 2 allows for maintaining the telescopic position without continuous power input. Furthermore, the drive nut 1's telescopic movement of the lead screw 2 provides higher rigidity, effectively improving transmission efficiency and positioning accuracy. Secondly, the position detection component 5 can detect the rotation angle of the drive nut 1 in real time, thereby detecting the extension length of the lead screw 2 and achieving high-precision position control. Moreover, the drive nut 1 acts as the rotation axis of the stepper linear motor, integrating the position detection component 5 inside the motor, resulting in a highly integrated, compact structure that is beneficial for miniaturization design. For bionic dexterous fingers, the cooperation between the drive nut 1 and the lead screw 2 can realize the conversion of rotational power to linear power. The position detection component 5 detects the rotation angle of the drive nut 1 in real time, which can accurately adjust the finger bending angle and control the finger bending position.

[0049] Furthermore, the outer housing 10 of the stepper linear motor is integrated with the outer shell of the drive finger joint 100. That is, the outer housing 10 of the stepper linear motor acts as the outer shell structure of the bionic dexterous finger. The overall structure is more compact, improving space utilization. A stepper linear motor with greater output power can be set in a limited space, thereby increasing the output power and outputting a larger and more stable gripping force.

[0050] For example, the position detection element 5 is embedded in the end of the lead screw 2 opposite to the end extending from the outer casing 10, that is, located at the tail of the stepper linear motor. Specifically, a first mounting groove is formed on the outer wall of the tail of the lead screw 2, and the position detection element 5 is embedded in the first mounting groove, with its detection end facing the inner ring of the drive nut 1. In some embodiments, the position detection element 5 can also be fixed to the end of the tail of the lead screw 2 to reduce processing costs.

[0051] For example, the position detection element 5 is a Hall sensor, a magnetic encoder, or a photoelectric encoder.

[0052] For example, the rotor 4 is made of magnet steel, and the rotor 4 and the outer periphery of the drive nut 1 are fastened together by adhesive; the stator 3 includes an iron core and a coil. The iron core is tightly fitted and fixed to the inner wall of the outer shell 10. The side of the iron core facing the outer shell 10 is provided with a winding groove, and the coil is wound in the winding groove. After the coil is supplied with alternating current, it drives the rotor 4 and the drive nut 1 to rotate together.

[0053] For example, the drive nut 1 can be made of high-molecular plastic materials such as polytetrafluoroethylene (PTFE) and polyurethane, which have excellent high-temperature resistance and wear resistance. The lead screw 2 is made of metal alloy materials such as S45C steel and SUJ2 steel, which have high strength, wear resistance, and high-temperature resistance. The material selection and matching of the drive nut 1 and the lead screw 2 can improve the transmission efficiency between them, reduce structural wear, and extend the service life of the stepper linear motor.

[0054] For example, such as Figure 2 As shown, the outer shell 10 is configured as a cylindrical structure, and the extension and retraction direction of the lead screw 2 is the same as the axial direction of the outer shell 10. The cylindrical structure of the outer shell 10 is adapted to the shape of the knuckles of a bionic dexterous finger.

[0055] For example, such as Figure 2 As shown, the drive nut 1 is rotatably mounted in the housing 10 via bearings. Specifically, the stepper linear motor also includes a first bearing 6 and a second bearing 7. The drive nut 1 or the drive rotor 4 is rotatably mounted in the housing 10 via the first bearing 6 and the second bearing 7. The first bearing 6 and the second bearing 7 are spaced apart and are respectively located at the two ends of the housing 10. The first bearing 6 and the second bearing 7 jointly bear the radial load and axial load of the drive nut 1 and the drive rotor 4.

[0056] In this embodiment, as Figure 2 As shown, the first bearing 6 is a radial bearing. The first bearing 6 is located at the end of the drive nut 1 that extends away from the lead screw 2. The first bearing 6 has a first inner ring 61 and a first outer ring 62. The first inner ring 61 is tightly fitted around the outer periphery of the drive nut 1, and the first outer ring 62 is fixed to the inner wall of the outer casing 10. The first bearing 6 can withstand the radial load of the drive nut 1 and the drive rotor 4 and provide radial support.

[0057] For example, such as Figure 2 As shown, the stepper linear motor also includes a locking block 8, which is locked onto the end of the housing 10 away from the lead screw 2. The locking block 8 extends inward into the inner cavity of the housing 10. A limiting step 12 is provided at the end of the drive nut 1 away from the lead screw 2. The locking block 8 presses against the side of the first outer ring 62 away from the lead screw 2, and the side of the first inner ring 61 near the lead screw 2 presses against the limiting step 12, thereby locking the first bearing 6 between the housing 10 and the drive nut 1. When maintenance and adjustment are required, the first bearing 6 can be removed by removing the locking block 8, which is simple and convenient.

[0058] In this embodiment, the first bearing 6 is a deep groove ball bearing. Of course, in other embodiments of this utility model, the first bearing 6 may also be a needle roller bearing or the like.

[0059] In this embodiment, as Figure 2As shown, the second bearing 7 is a thrust bearing. The second bearing 7 includes a thrust bearing plate 71 and a thrust bearing plate 72 spaced apart. A thrust step 11 is provided at the end of the drive nut 1 near the protruding end of the lead screw 2. An inner flange 101 is provided on the outer casing 10 corresponding to the opening where the lead screw 2 protrudes. The thrust bearing plate 71 abuts against the thrust step 11, and the thrust bearing plate 72 abuts against the inner flange 101. The second bearing 7 can withstand the axial load of the drive nut 1, providing axial support. Since the high-efficiency transmission stepper linear motor is used to drive the grasping action of the bionic dexterous finger, the lead screw 2 moves in the retraction direction during grasping. Therefore, the action resistance mainly exists in the retraction stage of the lead screw 2. Thus, the axial load applied by the lead screw 2 to the inner flange 101 of the outer casing 10 through the drive nut 1 is the largest. The second bearing 7, located here, is a thrust bearing, which can effectively bear the unidirectional axial force generated during grasping, improving the load-bearing capacity. The second bearing 7 cooperates with the first bearing 6 to achieve both guiding and load-bearing functions.

[0060] Furthermore, such as Figure 2 As shown, one side of the thrust step 11 abuts against the thrust shaft plate 71 of the second bearing 7, and the other side also serves as a shoulder structure to abut against the drive rotor 4, thereby defining the installation position of the drive rotor 4 and playing an auxiliary role in installation.

[0061] Furthermore, such as Figure 2 As shown, the inner diameter of the inner flange 101 is smaller than the inner diameter of the second bearing 7, and the inner flange 101 completely covers the second bearing 7 to completely protect the second bearing 7.

[0062] For example, the second bearing 7 is a thrust roller bearing or a thrust sliding bearing.

[0063] Example 2:

[0064] like Figure 3 As shown, based on Embodiment 1, this embodiment provides another stepper linear motor, which differs from Embodiment 1 in that:

[0065] The position detection element 5 is fixed to the end of the housing 10 away from the lead screw 2. Specifically, the position detection element 5 is indirectly fixed to the housing 10 through a locking block 8. The locking block 8 has a second mounting groove, and the position detection element 5 is embedded in the second mounting groove, with its detection end facing the outer ring of the drive nut 1. In some embodiments, the position detection element 5 can also be directly fixed to the side wall of the locking block 8 to reduce processing costs.

[0066] For example, another difference in the first embodiment of the stepper linear motor provided in this embodiment is that the first bearing 6 and the second bearing 7 are both angular contact bearings. The installation method of the first bearing 6 is the same as in the first embodiment. The second bearing 7 is located at the end of the drive nut 1 near the protruding end of the lead screw 2. The second bearing 7 has a second inner ring 73 and a second outer ring 74. The second inner ring 73 is tightly fitted around the outer periphery of the drive nut 1, and the second outer ring 74 is fixed to the inner wall of the outer casing 10.

[0067] Furthermore, the stepper linear motor also includes two locking rings 9. Locking rings 9 are respectively fitted on both ends of the drive nut 1. One locking ring 9 presses the first inner ring 61 against the limiting step 12, and the other locking ring 9 presses the second inner ring 73 against the thrust step 11 to help fix the first bearing 6 and the second bearing 7 and improve reliability.

[0068] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A stepper linear motor, characterized by The step straight motor comprises a shell (10), a stator (3) fixed to an inner wall of the shell (10), a drive nut (1) rotationally arranged in the shell (10), the drive nut (1) penetrating the inner ring of the stator (3), a rotor (4) arranged around the outer peripheral portion of the drive nut (1), a screw rod (2) linearly arranged in the shell (10), one end of the screw rod (2) extending out of the shell (10), the drive nut (1) being threadedly connected to the screw rod (2), the stator (3) being capable of driving the rotor (4) and the drive nut (1) to rotate together after being energized, so as to drive the screw rod (2) to linearly extend or retract relative to the shell (10), and a position detection member (5) mounted on the shell (10) or the screw rod (2), the position detection member (5) being used for detecting the rotation angle of the drive nut (1). The position detection member (5) is embedded on the screw rod (2) away from the end extending out of the shell (10); or The position detection member (5) is fixed to the shell (10) away from the end penetrating the screw rod (2). The position detection member (5) is a Hall sensor, a magnetic encoder or an optical encoder. The step straight motor further comprises a first bearing (6) and a second bearing (7), the drive nut (1) or the rotor (4) being rotationally mounted on the shell (10) through the first bearing (6) and the second bearing (7). One of the first bearing (6) and the second bearing (7) is a radial bearing, and the other is a thrust bearing; or Both the first bearing (6) and the second bearing (7) are angular contact bearings.

2. The stepper linear motor according to claim 1, characterized in that The first bearing (6) is a radial bearing or an angular contact bearing, the first bearing (6) being arranged at the end of the drive nut (1) away from the end extending out of the screw rod (2), the first bearing (6) having a first inner ring (61) and a first outer ring (62), the first inner ring (61) being tightly sleeved on the outer periphery of the drive nut (1), and the first outer ring (62) being fixed to the inner wall of the shell (10). The step straight motor further comprises a locking block (8), the locking block (8) being clamped on the shell (10) and extending into the inner cavity of the shell (10), the end of the drive nut (1) away from the end extending out of the screw rod (2) being provided with a limiting step (12), the locking block (8) being pressed against the side of the first outer ring (62) of the first bearing (6) away from the end extending out of the screw rod (2), and the side of the first inner ring (61) of the first bearing (6) close to the end extending out of the screw rod (2) being pressed against the limiting step (12).

3. The stepper linear motor of claim 1, wherein ​ 4. The stepper linear motor of claim 2, wherein ​ 5. A stepper linear motor according to claim 4, wherein ​ ​ 6. A stepper linear motor according to claim 5, wherein ​ 7. A stepper linear motor according to claim 6, characterised in that ​ 8. A stepper linear motor according to claim 7, characterised in that, The second bearing (7) is a thrust bearing, the second bearing (7) comprises thrust pads (71) and thrust seats (72) arranged at intervals, the drive nut (1) is provided with a thrust step (11) near one end of the lead screw (2) extending out, the outer shell (10) is provided with an inner flange (101) corresponding to the opening of the lead screw (2) extending out, the thrust pad (71) abuts against the thrust step (11), and the thrust seat (72) abuts against the inner flange (101); or The second bearing (7) is an angular contact bearing, the second bearing (7) is arranged on one end of the drive nut (1) near the lead screw (2) extending out, the second bearing (7) has a second inner ring (73) and a second outer ring (74), the second inner ring (73) is tightly sleeved on the outer periphery of the drive nut (1), and the second outer ring (74) is fixed to the inner wall of the outer shell (10).

9. A stepper linear motor according to claim 8, characterised in that, The first bearing (6) and the second bearing (7) are both angular contact bearings, the step straight motor further comprises locking rings (9), the drive nut (1) is sleeved with the locking rings (9) at both ends, one locking ring (9) presses the first inner ring (61) against the limiting step (12), and the other locking ring (9) presses the second inner ring (73) against the thrust step (11).

10. A biomimetic dexterous finger, characterized by The step straight motor comprises a terminal finger joint (200) and a plurality of drive finger joints (100) connected in sequence, the drive finger joint (100) comprises the step straight motor as claimed in any one of claims 1-9, one end of the lead screw (2) extending out of the outer shell (10) is drivingly connected with the adjacent drive finger joint (100) or the terminal finger joint (200) to drive the latter to rotate, and the outer shell (10) of the step straight motor is integrally arranged with the outer shell of the drive finger joint (100). The step straight motor comprises a terminal finger joint (200) and a plurality of drive finger joints (100) connected in sequence, the drive finger joint (100) comprises the step straight motor as claimed in any one of claims 1-9, one end of the lead screw (2) extending out of the outer shell (10) is drivingly connected with the adjacent drive finger joint (100) or the terminal finger joint (200) to drive the latter to rotate, and the outer shell (10) of the step straight motor is integrally arranged with the outer shell of the drive finger joint (100).

Images